Process of combining water-insoluble additament with organic fibrous material

United States Patent Office _Patented

3,016,325

PROCESS OF COMBINING WATER-INSOLUBLE ADDITAMENT WITH ORGANIC FIBROUS MATERIAL

Donald K. Pattflloch, New York, N.Y., assignor io Electro-Chem Fiber Seal Corporation, New York, N.Y., a corporation of Delaware

No Drawing. Filed Nov. 1, 1955, Ser. No. 544,134

Claims. (CI. 162—164)

This invention relates to the affixation of organic and inorganic additaments to fibrous organic and inorganic materials in aqueous suspension, such as, individual fibers and filaments, both nitrogenous, such as wool, hair, and leather; and non-nitrogenous such as cellulose and cellulose derivatives, and also, various synthetic fibers.

The art of affixing additaments to fibrous materials is well established, being exemplified by the dyeing of cellulosic filaments and fibers, by the sizing of paper, both while the fibers constituting the paper are in liquid suspension, or by the impregnation of webs of paper, and by the deposition of various materials, either upon suspended cellulosic fibers, upon filaments made thereof, or upon webs made therefrom.

A quite common mode of affixing additaments to such fibers is by conjoint deposition from suspensions in a liquid, or by impregnation of webs or fabrics by solutions or suspensions of the added substances. However, when such substances are merely in the form of dispersions or solutions, it has been the practice to soak or saturate webs of the materials with such solutions, which invariably required the elimination of the solvent employed, or involved the employment of molten materials.

In the art of sizing suspended paper fibers, such as is practiced in the making of paper, paperboard and molded pulp articles, various substances have been added in the hope that they would attach themselves to the suspended fibers in adequate quantities, but in most cases the amount that could thus be added was quite small.

I have now discovered that the initial treatment of an aqueous mechanical suspension of fibrous materials, the dispersed fibers of which carry an electronegative surface charge, with a cationically reactive, colloidal system of a potentially chemically reactive material, having an electropositive charge, and further characterized by the particles of the dispersed phase containing nitrogen groups and chemically reactive groups, effectively activates the dispersed fibrous material to render it highly receptive thereafter to the affixation of organic or inorganic additament material, applied to the so-treated fibrous suspension in a subsequent processing step.

I have also discovered that the cationically reactive, chemically active, fiber-activating material that is capable of being adsorbed on electronegative surfaces, from its colloidal system, should be potentially reactive, after adsorption, with additament complexes containing such reactive groups as OH, NH₂, COOH, CONH₂, CH₂OH, CHO, and SO_aH, and that significant improvements in operation may be effected as such a type of material offers possibilities of both physical and chemical bonding, and thus provides an effective means for the production of unusual water laid cellulose-complex webs, that are not possible to make by any presently known methods of operations.

In order to condense the descriptive matter of this application, the term “colloidal system,” as it will be used throughout the following examples, is a true and generic term, definitive of a two-phase, solids-liquid system, including those referred to conventionally as colloidal solutions, colloidal dispersions and colloidal suspensions the particles of the dispersed phase of which range between the presently accepted limits of 1 micron and 1 millimicron in size.

In the practice of this invention, the colloidal particles of the dispersed phase must carry an electropositive surface charge, which generally originates from ionization of the particle surface, or, in some cases, by adsorption of ions from the dispersant.

Coincidentally, the dispersed phase of the colloidal system must be potentially chemically reactive, with complexes containing such groups as OH, NH₂, COOH, CONH₂, CH₂OH, CHO or SO_sH.

It is well known that, in any solid-liquid system, when any two phases are in contact, the submicroscopically thin region between them is called the interface. Earlier concepts of the interface were based upon the formation of a double layer of ions of atomic dimensions, at the contact of solid and liquid, but it is presently understood that the interface is a diffuse layer, with a thickness greater than atomic dimensions, and that the ions are distributed in an ionic atmosphere. Whatever the concept of the interface between solid and liquid, it is wellknown that, at the interface there is a potential drop across the layer of ions that is termed the zeta potential, and is expressed by the equation:

4τΓβ(Ζ ^Z=~D~ where

Z—zeta potential e=electric charge of the double layer rf=thickness of double layer

D=dielectric constant of the particle

The zeta potential of dispersed, cationically reactive, colloidal particles is generally in the range of up to 100 millivolts, and seldom exceeds this value. The zeta potential of dispersed cellulosic fibers will vary with the type of fibrous material, and the amount of beating and refining that the fiber has been subjected to, as will be hereafter described.

The zeta potential of both the dispersed fibers and dispersed colloidal particles is of importance in the practice of this invention, as it is representative of the electrostatic barrier that exists at the contact between the solid and liquid phases of the several systems, which must be appropriately changed to permit the optimum results of process operation. In the untreated aqueous mechanical suspension of fibrous material, electronegative repulsive forces predominate, which are appreciably increased in their effect as beating continues and the ratio of fiber surface to mass increases. Consequently, the fibers are normally prevented from adhering to each other, since the electrostatic forces are of longer range than the shorter Van der Waals forces. Conversely, in the cationically reactive colloidal system, the dispersed particles carry electropositive repulsive forces, and likewise, the particles of the system are prevented from adhering to each other. If, however, the zeta potential of both the dispersed fibers and the dispersed colloidal particles, are decreased, through adsorption on the electronegative fiber surface, the colloidal particles cross the interfacial barrier and come within range of the Van der Waals forces. The colloidal particles will then adhere to each

3,016,325 ώ

other and to the adsorbate. Similarly, with the coincident decrease in the electronegativity of the dispersed fibers in aqueous suspension, there will be a corresponding decrease in repulsive electrostatic forces, and forces of cohesion will become more effective, to bring the dispersed fibers into more intimate contact while in the wet state in the water-laid cellulose-complex webs, and thus result in a closer and better formed web than is normally the case. It has been noted, that, without exception, all of the cellulose-complex webs made by the process of this invention are noticeably closer and better formed than normally made webs, regardless of the nature of fiber used, or the type of web forming device employed.

The addition of the cationically reactive, chemically reactive, colloidal system of the fiber activating material should be in sufficient amount to decrease the electronegativity of the dispersed fibrous material, but not in sufficient amount to reverse the polarity of this electronegative surface charge. Correspondingly, the electropositive charge on the colloidal particles of the dispersed phase of the colloidal system of the fiber activator is reduced by adsorption, and, with the coincident decrease in the electrostatic charges of both the dispersed colloidal particles of the fiber activator system and the dispersed fibers of the aqueous fiber suspension, the activated fibers, on whose surfaces the colloidal activator particles have been adsorbed, are brought within the effective range of Van der Waals forces and hence, both the fibers and the colloidal particles of fiber activator material adhere strongly to each other, in at least a physical, and probably, both a physical and chemical bonding.

The net result of this reaction is the formation of a closer, better formed, denser, water-laid, cellulose-complex web on the machine forming wire, as has been the case, without exception, in the instance of every machine production run made.

In order to further condense the descriptive matter of this application, several suitable fiber activating materials, that will be referred to in following examples, are hereafter described, it being understood at the very outset, that the practice of this invention is not in any way limited to the sole use of these materials, there being a number of other fiber activating materials that have been used and that will be described in following examples. One such suitable type of fiber activating material is a complex polymer, a reaction product of a cyanamid derivative, namely, dicyandiamide and formaldehyde. The fiber-activating material is the dispersed phase of a cationically reactive, chemically reactive, colloidal system of about 30% active solids content. The exact chemical structure is not known, but it contains a large proportion of nitrogen and reactive methylol groups. The cationically reactive nitrogen groups, coupled with the chemically reactive groups, make possible both physical and chemical bonding, and offer the possibility of reaction of such activated fibers with additament complexes containing such reactive groups as OH, NH₂, COOH, CONH₂, CHO, or SO₃H.

This activator is stable to most dilute acids and alkalis, alkaline earth salts, and heavy metal salts, such as, aluminum sulfate, zinc sulfate, and copper sulfate. Its cationic properties give the material an affinity for many negatively charged materials, as for example, cellulosic and other fibrous materials, so that it can be absorbed from a colloidal system by such materials. The material in itself cannot be further polymerized readily to give a water-insoluble resin, but the chemically reactive groups present permit reaction with amino compounds and compounds containing such groups as heretofore described to give complex resin polymers that, under suitable conditions, are potentially capable of condensation or polymerization reactions to form water insoluble complex products. This material has a particle size of about 1000--1500 Angstrom units.

Another example of a fiber-activating material is the complex; tetramethylolacetylenediurea, the structural formula of which is detailed below:

H

HOH2C— N— C— N— CHjOH O=C I C=O hoh₂c—A—c—chsoh

H

This material is prepared by reacting one mol of hydrated glyoxal with two mols of urea, and then reacting this intermediate product with four mols of formaldehyde. The resultant product is in the form of a colloidal system and is highly reactive. A colloidal system of 10% active solids has a pH value of from 2.0 to 2.5. This material in solid form attracts anions, definitely establishing its cation active properties. The particles of the dispersed phase are approximately 1000 Angstrom units in size. The presence of the chemically reactive groupings, and its cation activity, coupled with the fact that this material is classified as a resin former, for reason of its structure and chemical reactivity, makes it a most useful fiber activator material, it being potentially reactive with both the fibrous material, and with additament complexes containing such reactive groupings as heretofore described.

Another effective fiber-activating material is polymerized ethylene imine. This material is supplied as a heavy, viscous liquid of about 50% polymerized ethylene imine solids, alkaline in reaction, and having an ammoniacal odor. Ethylene imine in its polymerized form has a molecular weight of between 30,000 and 40,000' and is represented by the formula— / NH \ \CH₂--CHs/n where N is between 700 and 800. Ethylene imine is a heterocyclic compound, highly reactive, particularly in the case of addition reactions which are generally accompanied by ring opening.

Polymerized ethylene imine reacts with cellulose fibers through available hydroxyl groups and thereby effects a partial dehydration of the fibrous material.

For reason of its alkaline nature and the reactivity of cellulose fibers that have been activated by its use, polymerized ethylene imine has been most effective in bonding a novel type of acrylonitrile-butadiene copolymer, containing a reactive carboxyl group, to the so-treated fibers as is described in a following example. In its unpolymerized form ethylene imine is a liquid having an ammoniacal smell, a boiling point of 116.5° C. and a melting point of 8.5° C.

An aqueous colloidal system of polymerized ethylene imine has a pH value in excess of 7.0 yet the dispersed phase is cationically reactive.

Fiber-activating materials containing the guanidine cation have been usefully employed in the practice of this invention. The guanidine cation is represented by the following formula:

NH2 H_!N+=C^//\hi and among such compounds are the reactive di-nitriles potassium dicyanoguanidine, and ammonium dicyanoguanidine, and also salts of guanylurea, as, for example, the sulfate, phosphate and nitrate salts. Guanylurea is represented by the following formula:

NH O II 11 H2NCNHCNH2

Other fiber-activating materials, having a nitrogen-containing cation in their structure have likewise been usefully employed in the practice of this invention, as, for example, such materials as polyfunctional reactive triazines, of which acetoguanamine is a representative type.

3,016,325

The structural formula of acetoguanamine is detailed below:

HaC—θ'⁷ 'C—N.H;

II I

N N ''c^

NHs

Cyanohydrin compounds, as, for example, acetaldehydecyanohydrin, represented by the formula below, has been usefully employed in the practice of this invention:

H

H₅C-0-C=N I OH

Other compounds, having a nitrogen containing cation in their structure are amenable to the processes of this invention, provided, however, that such compounds are not derivatives of fatty acids, as, for example, saturated, aliphatic fatty acids as propionic, butyric, valeric, lauric, myristic, caprylic and others; unsaturated fatty acids of the monoethenoid type, as decenoic, dodecenoic, tetradecenoic, octadecenoic, docosenoic and others; unsaturated fatty acids of the triethenoid type, as hiragonic, linolenic, elaeosteric, punicic and trichosanic acids; unsaturated fatty acids of the tetraethenoid type, as parinaric, arachidonic and other unsaturated polyethenoid acids, such as, chipanodonic, visinic and scoliodonic acids; substituted saturated fatty acids, as isovaleric, phthioic and phytomonic acids; substituted unsaturated hydroxy acids, such as ricinoleic, licenic and gorlic acids.

The treatment of an aqueous mechanical suspension of a fibrous material, having an electronegative surface charge, with a predetermined amount of a cationically reactive, chemically reactive, colloidal system of a fiber activating material, of the characteristics heretofore described, will result not only in a decrease of the electronegativity of the fibrous surfaces but also a decrease of the electrostatic charges on the solid phase of the colloidal system, and, in addition, affords the possibility of the development of a fibrous material that is potentially chemically reactive with additament complexes, containing amino groups and such reactive groups as OH, COOH, NH₂, C0NH₂, CH₂0H, CHO, or SO₃H.

There are, therefore, several general types of additament materials that can be employed in the practice of this invention, one class of which, comprises colloidal systems of chemically reactive additament materials; a second type comprises cationically reactive, chemically reactive, additament materails, and a third class comprises cationically reactive, dispersions or emulsions of essentially non-chemically reactive additament materials, such as, for example, fully saturated synthetic or natural waxes, oils, elastomers and resinous materials; filler materials, such as, clay, talc, diatomaceous earth and the like; subdivided or comminuted metals, such as, zinc, aluminum, copper, iron and others; pigment colors, such as, resinated pigments, normal pigment colors, and a wide variety of other materials which are hereafter described.

I have found as a result of several thousand evaluations, that unactivated fibers in aqueous suspension have high and low points of electronegative surface charge, or nodal points of charge, resulting in an uneven deposition of cationic reactive additament material that may be added thereto; a limited pick-up thereof, and a soft, mossy type of deposit that is easily rubbed off. On the other hand, the treatment of fibrous material in aqueous suspension, with a cationically reactive, chemically reactive, colloidal system of a fiber-activating material, appears to act to distribute the charge or to level off the high points of electronegative surface charge, to give a more or less uniformly charged surface. Thereafter, the subsequent treatment of such activated fiber with a cationically reactive system of an additament material, whether chemically reactive or not, results in a more uniform deposit, the capacity of the fiber to accept the deposit is increased, the deposit is more firmly consolidated, it is more firmly affixed, and lumps are not present to rub off. The relative permanence of the deposit in aqueous suspension of the fibrous material is due to the fact that it is well distributed and hugs the fibers so closely that it is not abraded off, and this more intimate association brings it within the range of short range forces and hence makes the effect of the Van der Waals forces appreciably greater. Thus, it is possible to make novel cellulose-complex webs containing substantial amounts of subdivided or comminuted metals, such as, aluminum, zinc, copper and the like, in combination with varying amounts of elastomeric or resinous additament materials. Similarly, substantial amounts of filler materials, pigment colors, and the like, may be effectively combined with cellulose-complex webs, as may waxes, oils, and a wide variety of other additament materials, either alone or in combinations as will be described in following examples.

On the other hand, the treatment of an aqueous mechanical fibrous suspension, the fibers of the dispersed phase having an electronegative surface charge, with a cationically reactive, chemically reactive, colloidal system of a fiber-activating material the dispersed particles of which contain in their structure both nitrogen groups and chemically reactive groups, as heretofore described, will, by adsorption, of the cationically, chemically reactive activator particles on the fibrous surfaces, impart to the fiber a potential chemical reactivity with reactive additament complexes, and thus afford a means of production of variety of cellulose-complex webs that are not obtainable by any presently known methods of production.

It is therefore one of the objects of the present invention to activate fibrous material, to permit the more complete realization of unusual properties that are highly desirable but heretofore have been generally unattainable.

For example, some of the unusual products that have been made by the practice of this invention are: cellulosechemical complex webs of improved dimensional stability, exhibiting a minimum of fiber hysteresis and a minimum of dimensional distortion when subjected to long and repeated alternate cycles of high and low relative humidities at predetermined and controlled temperatures and such products are of great utility value as chart, map, blueprint and record papers; cellulose-chemical complex webs having a high degree of porosity, and, at the same time, an unusual degree of water-repellency, so much so, that the web can be considered as being made up of an almost hydrophobic fibrous material; cellulose-chemical complex webs that are highly resistant to penetration by hot food liquids, such as coffee, tea, cocoa, milk, etc., thus permitting the production of a superior type of hot drink container; cellulose-chemical complex webs that, in addition to an increased dimensional stability under varying atmospheric conditions, have also an abnormally high wet strength, and elastomeric properties that permit their use as food packaging material, abrasive' backing sheets, backing sheets for waterproof, dimensionally stable sealing tapes, and a variety of other useful products; cellulose-chemical complex webs possessing high dielectric strength, in combination with an unusual structural strength and with an improved dimensional stability, that are of high utility value as replacement of existing materials used in the electrical insulating field, such as, vulcanized fiber, resin laminated dielectric board, etc.; cellulose-chemical complex webs that are made up of up to equal parts of subdivided metal, such as aluminum; an elastomeric or resinous material and a fibrous material, such as any activated type of fiber. Such unusual webs are of value as thermal insulating material, electrical shielding material, food packaging material, gasket ma3,016,325 terial, grease- and oil- and water-resistant material, and a variety of other end uses; cellulose-chemical complex webs made up of essentially hydrophobic fibrous material, having an unusually high degree of porosity, excellent structural strength and an improved dimensional stability and being of great value as saturating base webs, it having been shown that the use of such unusual webs in saturating procedures greatly diminishes, if not completely eliminating, the danger of “blistering,” “blows,” and “separation” of the end product, generally resulting from the time-temperature conversion of such resin-saturated webs, in either die-stamping, molding or laminating operations; cellulose-chemical complex webs that are ideally suited as a material for coating purposes, having a high degree of porosity, permitting the web “to breathe,” and coincidentally an abnormal resistance to penetration of the porous web by normal types of coating materials, such as, clays, starches, glues, pigments, metallic dispersions, etc. Many other unusual types of cellulosechemical complex water laid webs may be produced by the practice of this invention, as it will be apparent to those skilled in the art, that, with a wide range of potentially reactive additament materials and combinations thereof, a virtually unlimited range of unusual products may now be developed.

A further object of the present invention is to so treat the cellulosic fibers that additional cross-linkages between their macro-molecular chains will be developed and thus substantially decrease the fiber solubility in cuproammonium solution; generally increase their dimensional stability, and also impart to these so-treated fibers a greter structural strength and improved resistance to breakdown by organic food acids and the like.

Still a further object of this invention is to provide a means whereby synthetic fibers may be bonded together to form a fibrous web on any conventional paper or paperboard machine, and also to provide a means whereby synthetic fibers may be better bonded together in the production of unwoven fiber webs or fiber molded forms.

The invention is applicable to any cellulosic fibrous material that lends itself to the formation of cellulosic webs or forms from its aqueous suspension.

As the reactions of this process, insofar as papermaking is concerned, are centered on the available hydroxyl groups of the cellulose fiber, and the amount of cellulose surface exposed, it follows that the development of additional fibrous surface, and hence, an increased number of hydroxyl groups, makes possible added process effects.

I have also discovered that the presence of reactive groups, other than the hydroxyl groups, within the cellulose structure make for added process effects. Pentosan groups within the cellulose structure of a hard wood fiber, pulped and processed by the well-known sulfate cooking process, are of great value in their reaction with a suitable fiber activator, such as, for example, tetramethylolacetylenediurea, and under suitable processing conditions, chemical cross linkages are built up within the fiber structure, to result in the drastic modification of this cellulosic fiber, and an improvement in the dimensional stability of water laid webs made therefrom.

Other reactive groups within the cellulose structure may likewise contribute to the development of unusual fiber characteristics. Among such groups are the lignins, and lignin derivatives.

Generally speaking, the more potential chemical reactivity the fiber initially possesses, the greater the effect of the activating chemical, and the greater the overall process effects. However, much consideration must be given to the mechanical processing of the pulp, as a conventional means of developing an increase in the specific surface of the fiber, and hence, an increase in the surface electronegativity and also an increase in the number and availability of reactive hydroxyl groups.

The two-dimensional cellulose colloidal system, with its multiplicity of available, reactive, hydroxyl groups, be8 haves in chemical reaction like a simple alcohol. It is at once obvious that with the impurer grades of cellulosic fibers, as, for example, the unbleached fibers and the mechanical wood fibers and certain hardwood fibers, this 5 reaction potential will be substantially increased by the presence of lignin, pentosans, and other reactive groups in the unpurified fiber; but, whatever the fiber, the degree to which reactions may be carried is dependent upon the extent of area of exposed fiber surface, which governs the j₀ degree of negative electrical surface charge on the fiber, and the number and type of available reaction zones, which govern the extent of addition or substitution reactions or other chemical reactions that are possible.

The term additament, will be used in the present specifijg cation and claims as the broad and proper generic term for any water-dispersible, emulsifiable, water soluble, or water-water soluble solvent soluble substance that may, by the processes of the present invention, become affixed to, or combined with, the activated fibrous material, either 2q by physical bonding, chemical bonding, or both.

Among the types of condensation polymers that are useful as additaments in the practice of the present invention are the following: phenolformaldehyde resins, furfural-phenol condensation products, resorcinol formal25 dehyde condensation products, resorcinol-modified phenolformaldehyde condensation products, ureaformaldehyde resins, cresolformaldehyde resins, melamine formaldehyde resins, the condensation reaction product of cyclohexanol, adipamide, adipic acid and hexamethylenedi30 amine, the trade name of which is nylon; the condensation reaction product of phthalic anhydride, glycerol and linoleic acid, the trade name of which is “Glyptal”; the condensation reaction product of cyclopentadiene, maleic anhydride, glycerol and linoleic acid, or Carbic resin; the 35 condensation reaction product of a dibasic acid, maleic anhydride, glycerol and styrene, e.g., Laminac resin; the condensation reaction product of sebacic acid, recinoleic acid and glycerol, e.g., Paraplex resin; the condensation reaction product of sebacic acid and ethylene glycol, e.g., 40 Paracon resin; condensation-polymerization products of ethylene oxide, or “Carbowax” resins; the condensation reaction product of ethylene dichloride and sodium tetrasulfide, e.g., “Thiokol A” resin; and condensation-polymerization products of dimethyldichlorosilane or “sili45 cone” resins.

Also, several types of varnish resins, such as paratertiary-butylphenolformaldehyde resins, paratertiarybutylureaformaldehyde resins, and paratertiarybutylmelamineformaldehyde resins are within the scope of the present 50 invention.

Other types of polymers adaptable to the process operation may include the following: Polyethylene, polystyrene, polydichlorostyrene, “Piccolyte” resins, coumaroneindene resins, polyisobutylene resins, methylmethacrylate 55 resins, ethylmethacrylate resins, isobutylmethacrylate resins, butylmethacrylate resins, polyvinylacetate resins, polyvinylchloride, polyvinylbutylate, allylalcohol copolymers, polyvinylethylether, polyvinylformadehyde, e.g., “Formvar” resins, and others.

Copolymeric types of plastics may include vinylidene chloride plus acrylonitrile, e.g., “Saran,” vinylchloride plus acrylonitrile, e.g., “Vinyon,” vinylchloride plus vinylacetate plus maleic anhydride, e.g., “maleic modified polyvinylchloride-acetate resin,” vinylidene chloride plus 65 vinylchloride, e.g., “Plioflex,” styrene plus drying oil, e.g., “styrenated oil,” cyclopentadiene plus drying oil, e.g., “cyclo oil” and others.

Special technical resins that are applicable to process operation are various types of synthetic rubbers.

Synthetic rubbers may include the following: butadiene copolymerized with styrene, e.g. “GR-S latex”; butadiene copolymerized with acrylonitrile, e.g., “GR-A latex”; isoprene copolymerized with isobutylene, e.g., “GR-1 latex”; a chloroprene polymerized product, e.g., “GR-M 73 latex”; a dimethyldichlorosilane polymerized product, e.g.,

3,016,326 “silicone rubber”; chlorohydrin plus formaldehyde plus tetrasulfide, e.g., “organic polysulfide latex”; polyisobutylene, e.g., “butyl rubber.” Other resins may include a class of resins known as the hydrocarbon resins. Those are highly resinous materials of varying molecular weights and flow points, and have a high utility value. Also included may be various types of asphalts, pitches, tars and the like.

The alkyd resins lend themselves to process operation and offer interesting possibilities in the production of new and unusual types of cellulose-alkyd resin complexes. Among such resins finding application to combination with cellulosic fibers in aqueous suspension, by the methods of this invention, are: pure alkyds of the drying type, phenolated alkyds, styrenated alkyds, resin modified alkyds and phthalic free alkyds.

The drying oils generally used to modify alkyd resins are linseed, perilla, oiticica, fish and tung oils, and in some alkyd resins use is made of soya bean oil, dehydrated castor oil, sunflower oil and walnut oil. The drying type of alkyd resins have a high degree of unsaturation due to their unsaturated fatty acid content and due to the four double bonds in the case of fish oil fatty acids. Such alkyd resins may be combined in emulsified form with ureaformaldehyde, phenolformaldehyde, cresol formaldehyde and other types of resinous materials to give unusual products that impart a high utility value to the fibrous complexes that may be evolved by their use..

Cationic dispersions of prevulcanized rubber latices, chlorinated rubber latices and other materials that are derived by modification of synthetic rubbers, are readily adaptable to formulation into useful emulsions or dispersions for use in the present process.

Natural gums and synthetic gums are readily formulated into cationically reactive dispersions or emulsions and therefore are adaptable to process operation.

Plasticizing materials may be combined with many water insoluble materials, where a plasticizer is tolerated, and unusual filming properties thus added to the water insoluble materials which generally, in the instance of plasticization, is of the plastic, resin or elastomeric type of water insoluble material.

There are many filling and loading materials that are readily adaptable to the operation of the process, as without exception, they can be formulated into cationically reactive dispersions, and may include the following water insoluble materials; asbestine, clays, bentonite, diatomaceous earths, gypsum, talc, basic lead carbonate, whiting, titanium oxide, natural baryates, lithophone, silica and others.

The waxes are all adaptable to the operation of the process; the natural waxes, the petroleum waxes, and the synthetic waxes, in all their grades and types, as all are capable of being solvated and subsequently emulsified with a suitable emulsifier. Many of the waxes, having melting points lower than the boiling point of water, may be melted and thereafter dispersed in an aqueous system, using a suitable dispersing agent.

Oils are also amenable to the process, such as, natural oils, e.g. vegetable oils, the mineral oils, and the synthetic oils’ and are all capable of being solvated and subsequently emulsified with a suitable and operable emulsifying agent. Many of the oils may be dispersed in aqueous media, by use of a suitable dispersing agent, as for example, a cationically reactive aqueous dispersion of casein that has been reacted with hydroxyacetic acid. Such materials may serve to plasticize cellulose and to impart unusual characteristics to cellulosic webs and forms, and many new types of cellulose-oil-complexes may be evolved.

There are a number of cellulose derivatives and modified celluloses that are likewise adaptable to the present process, such as: ethyl-cellulose, carboxymethylcellulose, methyl cellulose, ethylenecellulose, butyralcellulose, cellulose acetate and others. Nitrocellulose, although highly combustible in nature, has useful potentials in the operation of the present process.

It is to be noted that a number of maleic anhydride derivatives are of high utility value in this process, such 5 as, the maleic anhydride adduct of abietic acid, the maleic anhydride adduct of stearyl abietate, mannitol-sorbitolmaleate polyesters, glycol maleate polyesters, the maleic anhydride adduct of methyl linoleate, maleic-alkydphenolic resins, the maleic anhydride adduct of polycyclic 10 dienecarboxylic acids, mono- and polyadducts of nonconjugated fatty esters, the maleic anhydride adducts of propenylphenylesters. Maleic acid, maleic anhydride and maleic esters react with numerous other hetero-substituted vinyl and ethylene compounds to yield a wide variety of 15 useful, copolymeric products.

Other water insoluble materials may prove to be of value in the production of a cellulose-chemical complex web or form, and if such materials are adaptable to formulation into cationically reactive dispersions or.emul20 sions, they may be included in the practically unlimited list of water insoluble materials adaptable to the present invention.

Other technical materials that may be included in process operation are: chlorinated paraffins, chlorinated rub25 bers, rubber hydrochloride and many others.

There are many inorganic, organic and resinated pigment colors that are completely adaptable to this process of operation and so offer many new possibilities of coloring cellulosic products. Generally, these materials can 30 be formulated into an operable aqueous dispersion by the use of a suitable and operable dispersant.

The following colors are suggested as representative of this class of materials: lead sulfochromate, lead chromate, zinc chromate, “Hansa yellow,” a primary aromatic ³⁵ amine coupled with aceto-acetanalid, basic lead chromate, lead chromemolybdate, lead chrome green, iron blue pigments, Prussian blue pigements, “Lithol Reds,” the pigment produced by diazotizing 2-naphthylamine-l-sulfomc acid, coupling with betanaphthol and salting out with 40 either barium or calcium salts, resinated barium lithol red, toluidene red, e.g., 2-nitro-4-toluene-azo-beta-naphthol pigment, para reds, e.g., similar to the. toluidene reds, red lakes, e.g., the varium salts of 1-naphthol-azo2-oxynaphthalene-3-6-disulfonic acid, phthalocyanine blue, 45 phthalo-cyanine green, “Targetoner red,” e.g. an azo coupling of orthochloro-paranitraniline to betanaphthol, and many others.

There are, of course, many other types of coloring materials that can be readily made into suitable cationically 50 reactive dispersions for use in the process, such as: bone black, carbon black, lamp black, ochre, umber, cobalt blue, mineral brown, red lead, iron yellow, cadmium red, Tuscan red, cadmium yellow, graphite, whiting, blanc fixe and others.

Subdivided or comminuted metals may also be used, such as, aluminum, copper, zinc, lead iron, arsenic and others. Generally, these subdivided metals are formulated in aqueous dispersions, using a suitable emulsifier that will produce a cationically reactive dispersion of the com60 minuted metals. The use of such materials provides a novel means of producing metallized papers and fabrics for packaging, decorative, insulating or shielding purposes.

There are many types of chemically reactive additament 65 complexes suitable for use in the practice of this invention and, in order to condense the descriptive matter of the following examples, a few of the more unusual types will be hereafter described, it being understood that the practice of this invention is no way limited to the use of these 70 materials, but that a wide variety of reactive additament complexes may be successfully employed, many others of which will be described in the following examples.

One example of a chemically reactive additament is an ethanol-water soluble resorcinol formaldehyde resin, 75 made by reacting one mol of resorcinol with less than one

3,016,325 mol of formaldehyde. This condensation reaction may be effected in the absence of a catalyst; by the use of an acid catalyst; or, by the use of an alkaline catalyst with no significant changes in the properties of the resinous product resulting therefrom. The resin solution, as supplied by the manufacturer, is from 50% to 55% solids content of a specific gravity of from 1.125 to 1.130, and with a pH value at 20° C. of from 5.5 to 7.4, dependent upon the type of catalyst used. The viscosity of the solution, as received, will range from 100 to 300 centipoises at 20° C. The color of the solution will vary from a light rose to a deep rose shade, dependent upon the pH of the solution, as resorcinol formaldehyde resin is an indicator type of resin. The molecular weight of the resin is approximately from 140-150.

Like all polyhydric phenols, this resin has an extremely high reactivity. This reactivity of resorcinal formaldehyde resin is attributable to the structure of resorcinol, and is probably due to the reinforcing position of the hydroxyl groups, both being attached to unsaturated carbon atoms with the initial substituent being in a position ortho to one hydroxyl and para to the other. The structural formula for resorcinol is detailed below:

on !

HC^Z \h I II

HC C—OH

V H

Another type of a chemically reactive additament material is an alkaline, catalyzed, condensation reaction product of phenol and formaldehyde, the condensation reaction being taken to its lowest possible stage. As a consequence, tills resin is highly reactive. All factors in processing have been eliminated that would tend to advance this A stage resin, and hence reduce its activity.

As received, the resin is in the form of a clear, light brown, colored, mobile aqueous colloidal system of about 50% resin solids content. The critical characteristics of this resin are detailed below:

Molecular weight------------------ 110 approximate.

Specific gravity_____________________ 1.138.

Centipoises viscosity_______________ 14.

pH of 10% aqueous system_________ 8.2.

N.V. solids at 135° C______________ 50.2%.

An unusual type of chemically reactive additament complex is an acrylonitrile-butadiene copolymer, characterized by a high acrylonitrile ratio, and by the presence of a reactive COOH group in the carbon chain, there being one such COOH group for every 100 carbon atoms. This material is made by an emulsion-polymerization process, and is in the form of a colloidal system, the particles of the dispersed phase averaging about 1200 Angstrom units in size. The active solids of the colloidal system are approximately 40%, the specific gravity is 1.00. The viscosity of the colloidal system is 12 centipoises, using a Brookfield #1 spindle at 60 r.p.m. The average surface tension is 34 dynes per square centimeter.

This complex elastomer, thermoplastic in its original properties, may be crosslinked by the addition of about 1 part of sodium aluminate solids per 100 parts of elastomer solids, the sodium aluminate being added to the colloidal system of the elastomer as a 2.00% solids content solution. Thereafter, the elastomer becomes a thermosetting type of material, after curing has taken place. Reacted in this way, the crosslinked elastomer will fully cure in from 2 to 3 days at room temperature and, when used, will produce films having tensile strengths of from 3,000 to 4,000 pounds per square inch.

Another novel type of reactive additament is an ammonia-rosin complex, containing reactive amide groups and probably also a reactive methylol 'group. Rosin, whether of the wood or gum type is a colophony resin, by far the most predominant constituent of which is the carboxylic acid of a diterpene having a molecular weight 5 of 302 and the generally accepted structural formula:

ch₃ COOH

<img file="US3016325A_D0001.tif" />

It contains two reactive conjugated double bonds in rings I and II, and has the probable formula of dimethylisopropyldecahydrophenanthrenecarboxylic acid, or the more common name of “abietic” acid. Other acids present in rosin react similarly to abietic acid in respect of the herein described reaction with ammonia.

This complex additament is prepared by first dissolving wood rosin or gum rosin in methanol, about 300 parts of methanol being used to dissolve 400 parts of rosin 25 solids. Therefater, the methanol solution of rosin, is reacted with about 300 parts of 26° C. aqueous ammonia at a temperature of approximately 90° C., and the mass digested with refluxing, for from 6 to 8 hours. The reaction produced at this temperature is a slightly viscous 3θ fluid a colloidal system, light brown in color, that rapidly forms a soft, dispersable gel as the temperature drops below 120° F.

It has been found that use of other water-soluble solvents for rosin, such for example as ethanol, denatured 35 ethanol and isopropanol do not result in production of an ammonia-rosin complex having the outstanding sizing values characteristic of the above-described material. Likewise, it has been found that the reaction of ammonia with an aqueous dispersion of finely divided rosin does 40 not result in production of a size at all comparable to that described above.

Because of the presence of the volatile ammonium ion in the above-described complex, and because of the total absence of the hydrophilic sodium ion normally found in 45 conventional rosin sizes, the above described complex, when used as a “straight” sizing material per se, enhances the hydrophobic nature of fibers treated therewith.

The above complex material is reactive with various types of resinous materials as, for example, resorcinol 50 formaldehyde, phenol formaldehyde, cresol formaldehyde, as well with complexes containing such groups as carbonyl groups and amino groups, as in its preparation some degree of ammonolysis has taken place, with the formation of reactive RC0NH₂ groups. This additament material 55 has been used extensively, with suitably activated fibers, either alone or in combination with other reactive additament materials, as will be described in the following examples.

A few examples of cationically reactive, essentially non60 chemically reactive additament materials are now described, it being understood that the practice of this invention is in no way limited to the use of these few materials, but that, on the contrary, any water insoluble material capable of being formulated into a cationically re65 active dispersion or emulsion may be employed in the practice of this invention.

One material of this type is an aqueous cationically reactive dispersion of a high molecular weight polyvinylethylether of the following basic formula:

(C₂H₅OGH=CH₂)_n—where n is 10 to 20

The resin dispersion is made with from 2% to 4% of a high molecular weight, aliphatic amine as the dispersing agent. This complex amine consists of approximately 75 25 parts octadecylamine; 70 pails octadecenylamine; and,

3,016,325 parts 9-12 octadecadienylamine, an unsaturated amine of the chemical formula:

CH₃ (CH₂) ₄CH=CHCH₂CH=CH (CH₂) ₈NH₂

The dispersing agent is water dispersible, with a molecular weight of 311. The mean molecular weight of the primary amine content is 264. The melting point is approximately 57° C. and, as received, is a red-yellow waxlike solid. This amine dispersing agent is reactive with carbonyl groups, and can condense with them in the presence of an acid catalyst.

The aqueous dispersion of the resin, as made, is white in color, of low viscosity, and with a resin solids content of 45%. It is readily dilutable to as low as 1% resin solids. At that concentration, it has excellent stability. The pH value of a 10% resin solids dispersion is 7.5 at 20° C. and the particle size is less than 1 mu.

Another useful material is a special type of pigment emulsion of 24% pigment solids, that is readily dispersed in water to as low as 5 % pigment solids dispersion, having excellent stability. The pigment used in this instance, although many others can be emulsified by the same procedure, was phthalocyanine green; the chlorinated, co» ordinated copper complex of tetra-azo-tetra-benzo-porphin. This emulsion is prepared by first wetting, and partially dispersing the pigment color in an approximate 2.25% solution of a nonionic, wetting agent, and dispersant of the following chemical formula:

RO

Z=o licFo (CiHiO-JnH which is an ester of phosphoric acid in which one of the hydrogen atoms is esterified with polyethylene glycol, and the other two hydrogen atoms are esterified with hydrophobic alcohols of medium chain length.

A 0.20% aqueous solution of this nonionic wetting agent has a surface tension of 28.8 dynes per sq. cm. at 29° C. As received from the manulfacturer, it is an amber liquid having a specific gravity of 1.121 at 28° C. a pH value of 7.00 at 20° C. and is nonfoaming in both acid and alkaline solutions. It has an excellent ability to carry dyestuffs and pigments, and provides uniform penetration. It is insoluble in naphtha, forms a milky solution in water, and a clear solution in alcohols and acetone.

The wetted-out pigment was then emulsified by the use of about 10% (on the pigment solids weight) of an aliphatic amine emulsifying agent, consisting of approximately 25 parts octadecylamine; 70 parts octadecenylamine; and, 5 parts octadecadienylamine, the aliphatic amine being readily dispersible in water.

The emulsification of the pigment color was in accordance with the following procedure: 24 parts pigment color were dispersed in 45 parts water, containing 1 part of the nonionic wetting agent, to which dispersed mixture was added with high speed agitation, an aqueous solution of the emulsifier consisting of 2.4 parts emulsifier solids, dissolved in 27.6 parts water. The resulting O/W type of emulsion contained 24.00% pigment solids. This pigment is highly resistant to light, acids, and alkalis, and has been successfully used in the production of light-fast, washable, shade, drapery, and similar materials made from cellulose-complex webs, as described in a following example.

Other types of pigments are readily processed into stable emulsions by the type of procedure used in the production of this additament, such as, phthalocyanine blue; unchlorinated tetra-azo-tetra-benzo-porphine; hansa yellow; a pigment resulting from the coupling of a primary aromatic amine with aceto-acetanilid; lithol red, a pigment produced by diazotizing 2-naphthyl-amine 1-sulfonic acid with betanaphthol and salting with barium; toluidine red, a 2-nitro-4-toluene-azo-beta-naphthol; madder lake, a calcium salt of alizarine precipitated on alumina hydrate; and numerous others. Dispersions of comminuted metals may also be prepared by this procedure, as well as suitable dispersions of the many filler materials, such as, clays, talc, bentonite, etc. Waxes and oils are also amenable to this type of emulsion formulation.

Another useful material is a cationioally reactive suspension of a polyamide resin, the resin being made by the condensation of dimerized linoleic acid and ethylene diamine in accordance with the following reaction

O o ¹⁰ sHO-C-R— C-OH+tsHjN-CHj-CHj-NHs---»

Dilinoleie acid Ethylene diamine / ° ° \

HO C—R— C—NH- GHz— CHj- NH/JI

Polyamide resin (where n=5 to 15)

The base resin produced by this condensation has a softening point of 105°-115° C. It is resistant to water, alkali mild acids, oils, greases, gasoline and aliphatic solvents. 20 The resin is amber colored with a specific gravity of 0.97 to 0.99, and an acid number of approximately 7. The molecular weight of the base resin is from 3000-6500. The resin suspension is of 35% resin solids content with a viscosity of 0.4-0.9 poises at 25° C. The color is 25 opaque white, the particle size averages less than 1 micron. The pH of the suspension is about 5.2 at 20° C. The acid number is from 3 to 5. The suspension has excellent mechanical stability, a very slow setting rate, is free from odor, and its weight is 8.4 pounds per gallon. 30 This material is reactive with epoxy type resins, for example, the chemical reaction taking place across the terminal end groups of the polyamide resin, the resultant product being a polyamide modified epoxy resin that is suitable for use in the production of dielectric materials, 35 as is described in the following examples.

A completely unique class of additament materials, of a polyfunctional nature is described hereafter. These materials, soluble in water-isopropanol solutions are both cationically and chemically reactive, and have the ability 40 to cross link polymers by reaction through double bonds. In addition, they may be usefully employed to adjust pH values of treated fibrous suspensions, coincidentally with a possible cross linking of the processed fibrous material. This unique class of polyfunctional additament 4- materials embraces the Werner complexes, coordinated chromium complexes, several types of which are hereafter described.

One such complex is one in which methacrylic acid is coordinated with chromium to form methacrylato chromic ₆₀ chloride. It is supplied by the manufacturer in an isopropanol-acetone-water solution of a dark green color, containing about 20% of methacrylato chromic chloride. This solution is dilutable with water in all proportions and possesses excellent stability. The specific gravity ₅₅ of the solution is 1.0263 at 20° C.; the boiling point is 180.3° F. (iso-propanol). The pH of the solution is 1.80 approximately.

A solution of methacrylato chromic chloride will polymerize to form Cr—O—Cr linkages on condensation, or ₆₀ dehydration. The Cr+++ cation of the complex is extremely reactive, and coupled with the residual unsaturation of the methacrylic acid component gives to methacrylato chromic chloride, the ability to cross link reactive polymers by reaction through the double bonds.

Methacrylato chromic chloride has the structural formula:

H₂C=C—CHs

C1₂C CrClz

<img file="US3016325A_D0002.tif" />

The molecluar weight is 347.89. Methylcrylato chromic

3,016,325

IS chloride is capable of forming both chemical covalent and polar bonds with complexes containing such groups as OH, NH₂, COOH, C0NH₂, CH₂0H, CHO, or SO₃H.

Another type of Werner complex is that in which 2furoic acid is coordinated W'ith chromium to form 2furato chromic chloride.

2-furoic acid is a highly reactive heterocyclic oxygen compound, having a carboxyl group attached to an unsaturated carbon atom, and has the chemical formula:

HC·---CH

II II

HC C—COOH o^Z

2-furato chromic chloride has the formula:

H C=CH ^X'C=CH

I

OhCr CrOh

V

H

It is supplied in an iso-propanol-water solution of about 30% solids content. Like other Werner complexes, 2furato chromic chloride forms Cr—O—Cr linkages on polymerization, brought about by condensation or dehydration. Not only is the chromium cation CR+++, extremely reactive; but, coupled with 2-furoic acid, the complex is capable of forming both chemical covalent and polar bonds with complexes containing OH, NH₂, COOH, C0NH₂, CH₂OH₂, CHO, or SO₃H groups, thereby being potentially capable of crosslinking reactive polymers.

This is still another type of Werner complex, in which alpha-resorcylic acid is coordinated with chromium to form alpha-resorcylato chromic chloride.

Alpha-resorcylic acid normally finds application in the synthesis of azo and oxazine dyes. It has the chemical formula:

Alpha-resorcylato chromic chloride has the chemical formula:

<img file="US3016325A_D0003.tif" />

It is supplied in an iso-propanol-water solution of about 30% solids content. A solution of alpha-resorcylato chromic chloride will polymerize to form Cr—O—Cr linkages upon condensation, or dehydration. The chromium cation, C+++, is extremely reactive; and coupled with alpha-resorcylic acid, the complex is capable of forming both chemical covalent and polar bonds with complexes containing such groups as OH, NH₂, COOH, CONH₂, CH₂OH, CHO or SO₃H groups, and thereby is capable of cross-linking reactive polymers.

Another type of Werner complex that has been found useful is that in which an amino-benzoic acid, anthranilic acid, is coordinated with chromium to form anthranilate chromic chloride. Anthranilic acid is the most important 5 of the amino-benzoic acids. It is used as the starting material in the preparation of indigo. It crystallizes from solutions in white leaflets, having a M.P. of 145° C. It is moderately soluble in water, and its aqueous solutions show a blue fluorescence. Anthranilic acid has the chem10 ical formula:

COOH I c '''c—nh₂I II

HC CH

H

Anthranilato chromic chloride has the chemical formula:

<img file="US3016325A_D0004.tif" />

³⁰ A number of chemical reagents may be advantageously used to adjust the pH value of the treated fibrous suspension, and, in order to condense the descriptive matter of the following examples of the practice of this invention, there will hereafter be described a number of the reagents ³³ used. It is to be understood, however, that the practice of this invention is not limited to· these reagents, as other reagents of similar functionality may be successfully employed.

Among these reagents are:

⁴⁰ An aqueous solution of aluminum formate of approximately the following composition:

Specific gravity------------------------- 1.11-1.12

Percent A1₂O₃-----------,---------------5.5 .- pH of 1% solution at 20° C.______________ pH 4.0 ° Formic acid____________________________13.5-14.0

Sulfates________________________percent .0000

Barium Trace

Calcium ______________________percent—0.1

Of the more commonly used pH adjusting chemical reagents, papermaker’s alum is generally used in the paper industry, both as a coagulant and acidifying reagent. It has the formula A1₂(SO₄)₃18H₂O. Other chemical reagents that have been used for this purpose include glacial 55 acetic acid which has been used in a number of examples as the pH adjusting chemical. It has the formula: CH₃COOH.

Formic acid has been used in several of the examples as a pH adjusting reagent. It has the advantage of a 00 low boiling point, and volatilizes at about 100.2° C. Accordingly, little, if any, unreacted formic acid is residual in the processed cellulose-chemical complex web.

Other organic acids, such as, lactic, hydroxy acetic, and others may be used for this purpose, and a wide variety 65 of water-soluble acid salts of polyvalent metallic ions are likewise found to be effective in the practice of this invention.

It is to be understood, however, that the practice of this invention is not limited to the above-described pH 70 adjusting reagents, but that any water-soluble reagent may be used that will effect a change in pH values of the aqueous suspension of treated fibrous material, provided, however, that the reagent selected for use does not detract from the potential effects to be developed in the fin75 ished cellulose-chemical complex web.

3,016,325

Although the present process was initially developed for use in the paper and paperboard industry, where cellulosic fibers are carried in aqueous mechanical suspension until the paper or paperboard is formed in a web on the conventional equipment used for such production, extended studies have been made in the application of these processes.

The processes are also equally adaptable to pulp molding operations and to the production of unwoven fabrics.

While many of the examples hereinafter to be recited deal with the art of pjper or paperboard making, it is to be understood that the invention is not limited thereby.

The examples which are hereinafter recited, are but a few of many hundreds of examples that have resulted from the evaluation of the processes of this invention. A number of them are in the form of records of actual production runs, m:de for the purpose of establishing the machine reproducibility of laboratory data, others are examples based on the results of carefully controlleu laboratory studies. All of them clearly show the significant improvements in the processing of fibrous materials over presently known methods of operation and establish the generic nature of this invention.

EXAMPLE 1

This example was conducted in a northern board mill using a relatively hard water supply.

This example was a large-scale run on a commercial four-cylinder board machine. The purpose of this run was to produce a superior packaging material, of abnormally high resistance to water and food acids, and with some degree of resistance to oils and greases.

Approximately 450 pounds of bleached kraft pulp, bone dry basis, were furnished to each of two mill beaters, one beater being of the standard Holland type, the other beater being a short cycle Umpherson beater. The pulp was well brushed and carefully beaten to defiber without excess cutting and to develop a long, partially hydrated fiber. The initial stock freeness was approximately 900 Schopper Riegel standard, and the percentage of shrinkage on drying was about 6.75%. The stock in the two beaters was reduced to 795 freeness Schopper Riegel standard, and to a shrinkage on drying that averaged 12.00%. At this point, exactly 0.15% on a solids basis of a complex cyanamid-aldehyde reaction product previously described as a fiber activator was added in the form of a 5% aqueous colloid solution, and the beater stock circulated with the rolls raised for about 20 minutes to complete the reaction.

Thereafter, exactly 3.00% of a maleic anhydride rosin adduct was added as a 10% solids content dispersion and the beaters circulated 10 minutes to effect a uniform mix and reaction. Subsequently, 0.50% on a solids basis of a cationic reactive dispersion of polyvinylethylether, prepared by the use of a cationic casein type of dispersant was added in the form of a 10% solids content dispersion, and after a short circulation of the beater stock, exactly 0.50% of a composite cationic reactive wax dispersion was added, consisting of 40 parts by weight of a high melting point paraffin wax, 50 parts by weight of a microcrystalline wax and 10 parts by weight of a refined beeswax, the composite waxes being melted, and dispersed in aqueous media again using a cationic dispersant casein glycollate as the dispersing agent. After a 10 minute beater circulation, a 10% solution of alum was added to adjust the pH value of the treated stock to about. 4.0 pH, approximately 6% of alum being used. Thereafter, the treated beaters were dumped to a common beater chest, equipped with agitators, and the stocks well blended before being pumped through the Jordans and to the machine stock chest. From there the stock was again pumped, this time to the machine stuff box, and thence to the mixing box, screens and cylinder head boxes, and thereafter formed into a cellulosic-chemical complex web as in normal paperboard manufacture.

¹⁸

No trouble was evidenced throughout the entire run. The pH of the cylinder vat white waters averaged 5.2 pH. No foaming occurred at any point in process flow, and there was no sticking tendency on the wires, felts, presses or dryers of the paperboard machine. The board was dried to a normal moisture content of about 5%, and after leaving the dryer train was run through a light, two-roll machine calender stack to give a smoother surface finish.

The resulting paperboard showed exceptional characteristics as detailed below. It is considered an unusual board product and is of high utility value as a packaging material of many potential end uses.

Average test data

Pounds per 100 square feet 8.00

Caliper_________________—________inches__0.01968

Density _________________________— 0.774

Bursting strength, #/sq. in. 172

Grams te r—machine direction--------------486

Grams tear—Cross machine___________ 715

Tensile strength #1 strip, M.D. 162

Tensile strength #1 strip, C.D. 52

Percent elongation, M.D.____________percent—3.75

Percent elongation, C.D.-------------do----10.00

Small containers made of this board were filled with various liquids to observe the time required to penetrate the board. During the time of test no penetration was evidenced—and from all indications the containers would hold the liquids for an indefinite period. The liquids tested were:

Water—no penetration of board in 56 days

Evaporated milk—no penetration of board in 30 days Motor oil SAE 10—no penetration of board in 42 days

As the board made has an average basis weight of. about 240# 24'' x 36—500, which is about the weight of standard milk container board, it can be seen that this board is a superior product for the packaging of milk, cream and other dairy products. It is obvious also that this board, with its high structural strength and resistance to penetration by a light motor oil, could be utilized iri the packaging of such, oils, as well as greases and fats of various types. As the board also has a high resistance to penetration by lactic acid, citric acid and the like, it would be of great value in the packaging of citrus fruits and citrus juices.

EXAMPLE 2

This example was carried out in an eastern specialty mill, using a Fourdrinier machine trimming 100 inches. The water supply used at the mill was extremely so't, averaging less than 20 p.p.m. total hardness. The pulp processing was initially done in a Hydrapulper, and the pulp finished in conventional type of Holland beaters of 2,400 pounds’ capacity. The Fourdrinier machine was equipped with two large Jordans in series, eight 4 Vortraps, a rotary screen, two primary presses and a smoothing press, and two dryer sections, the first consisting of 24 dryers, each 4 feet in diameter, and the second section consisting of 8 similar dryers; the steam pressure in both sections could be controlled over a relatively wide range. In addition, the paper machine had a tub size press, midway between the dryer sections and two 7-roll calender stacks, the first of which was equipped with water boxes, and steam showers, and the second of which was equipped with steam heated rolls for use in conjunction with the use of water boxes and/or the steam showers. The finished paper was slit and rewound in a two-drum rewinder, and thereafter made into smaller rolls or flat sheets, as desired, in a well-equipped finishing room.

The purpose of this machine run was to develop a recording chart paper of improved dimensional stability, when subjected to varying and drastic changes in rela8,016.325 .

tive humidity and temperature such as the paper might be subjected to in actual use.

Preceding this production run, over six hundred laboratory evaluations had been made to establish the basic factors that governed the production of such an unusual paper product.

, It is well known that any improvement in the dimensional stability factors of paper by chemical means can only result from an effective supplementary cross-linking of the macromolecular chains of the cellulose fibers. It is also known that sizing as such has no value in the improvement of dimensional stability. Also, it is known that the freeness of the stock used is an important factor in the improvement of dimensional stability, as generally the more hydrated the pulp, the less the dimensional stability. It is not known, however, and I have discovered that the best dimensionally stable sheets can be produced from cellulose fibers that are relatively mechanically inert, but chemically reactive. I have further discovered that, in the development of this type of paper product, there is a pronounced specificity as relates to the fiber activating chemical, and the subsequent resinous additaments, and that any radical departure from the basic types of these materials used will resu’t in the production of a sheet of poor dimensional stability. I have also discovered that the use of tub sizing materials for the purpose of increasing the ink repellancy of the paper, such as, fur examnle, silicone resin tub sizes, fluoro-chemical tub sizes, glue tub sizes, starch tub sizes, etc., will result in a measurable decrease in the dimensional stability of the paper so tub sized, a result that could not have been expected.

I have further found that the use of water boxes, or steam showers on the calender stack, for the dual purpose of imparting a higher finish to the paper end, at the same time, theoretically, at least, releasing some of the mechanical strain built into the paper, only serve to decrease the dimensional stability of the paper so treated. I have also discovered that, having formed the wet stage reaction mass of cellulose-chemical complex the water in this web can best be removed on the form'ng wire rather than by pressing action, as using drastic pressing action on such a processed web effects a marked reduction in dimensional stability.

Contrary to conventional concepts of the production of such a paper, I have found that mechanically inert, or hard-to-hydrate fibers such as hardwood su’fate pu’ps, that are more than normally chemically reactive for reason of the presence of non-fibrous materials, such as, for example, pentosan groups, are well suited to the production of such an unusual paper. Likewise, I have found a definite specificity of fiber activating material, it being obvious that the fiber activator must be potentially chemically reactive with such residual pentosan groups and/or primary alcoholic hydroxyl groups contained within the fiber. One type of a suitable fiber activator is the resin former, tetramethylolacetylenediurea, which is soluble in water, and can thus readily penetrate the channels and capillaries of the fibrous structure. Upon treatment of an aqueous suspension of a selected fibrous material, with an aqueous colloid solution of tetramethylo’acetylenediurea, a fiber activator potentially cationically reactive through its ring nitrogens, a reaction takes place, presumably between the available alcoholic hydroxyl groups, and the pentosan groups present, and it appears that the so-activated fiber is further reactive with an aqueous colloid solution of colloidal suspension of a cationic ureaformaldehyde condensation reaction product; this ureaformaldehyde condensation reaction product being made by condensing urea and formaldehyde to the lowest stage possible, to give a product of low molecular weight and high reactivity; and yet one that is capable of further condensation under suitable acid conditions to a hard, insoluble resinous product.

I have also discovered that, although a paper of improved dimensional stability can be made by the process of this invention, consisting of the initial activation of the fibrous material in aqueous suspension with an appropriate amount of an aqueous solution of tetramcthylolacetylenediurea and, after such activation cycle is com5 pleted, reacting the so-activated fibrous suspension with a suitable aqueous solution or colloidal suspension of a cationic condensation reaction product of urea and formaldehyde, then subsequently acidifying to a pH value of about 4.5 pH, with a suitable pH adjusting chem10 ical, for example, an aqueous solution of aluminum formate, thereafter forming the wet cellulose-chemical complex water laid web, and subsequently drying, yet such a paper product, although having excellent dimensional stability, is unsuited for use as recording chart paper, 15 map or blueprint paper, as it does not have satisfactory resistance to penetration by chart inks. Attempts to develop such a desirable ink resistance by means of tub sizing, with various types of tub sizing materials, as heretofore described, resulted in the production of a suitable 2o paper insofar as resitsance to ink penetration was concerned, but it was also found that the tub sizing operation, regardless of the nature of tub size used, seriously decreased the heretofore excellent dimensional stability factors of the processed paper.

I, then discovered that the use of a relatively small percentage of a special rosin additament, e.g., the ammonia-rosin complex heretofore described, subsequent to the reaction with the cationic colloid solution or colloidal suspension ureaformaldehyde and, prior to the adjustment 30 of pH values, not only produced a paper that was abnormally resistant to ink penetration, even to ethylene glycol types of ink, but that also the dimensional stability of the paper so made was noticeably enhanced.

EXAMPLE 3 35

A machine run was made for the specific purpose of producing a hot drink cup stock of greater than normal resistance to penetration by boiling coffee and having also a superior structural strength. Such a product, in vari₄₀ ous weights, should be of great value as a superior food packaging material.

The pulp furnish for this run was a mixture of 50% on a solids basis, of a bleached hardwood kraft pulp, and 50%, on a solids basis, of a bleached softwood kraft pulp. Tire pulps were blended and initially defibered in ⁴⁵ a hydropulper, the processing time being thirty minutes. Thereafter, the blended pulp furnish was pumped to each of two Holland type beaters, approximately 2,000 pounds of bone dry pulp being furnished to each beater. Beating wss continued for a period of 3 hours to reduce the furnish to about 490 Canadian Standard freeness. Thereafter, exactly 0.50%, on a solids basis, of a cyanoaldehyde condensaiton reaction product, a fiber activator previously described, was added to each beater, and reacted with the beater stock for one-half hour. Then, ⁵⁵ 4.0%, on a solids basis, of the special ammonia-rosin complex, previously described, was added to the activated beater stock, the material being added in the form of a 10% solids colloidal suspension. An immediate reaction took place between the activated stock and the addita⁶⁰ ment, the beater stock gradually assuming a light yellow color, the liquid phase of the beater becoming crystal clear. At the end of a 20-minute reaction cycle, the beater stock being between 95° F. and 100° F., the pH of the beater stock was adjusted to 4.2 pH, using a 10% ⁶⁵ solution of papermaker’s alum for this purpose, and, thereafter, the finished beater stock dumped to the beater chest.

From the beater chest, the treated stock was pumped to the Jordan head box, and thence through the Jordcns, 70 and by a light Jordanning action the freeness of the treated stock was reduced to about 475 Canadian Standard freeness. Thereafter, the stock was flowed through the Vortraps and rotary screen to the head box of the paper machine, which was operated at a speed of 75 410 f.p.m.

3,018,325

The cellulose-chemical complex web was subjected to heavy pressing action on the first and second presses, and the smoothing press of the machine was used.° Dryer temperatures were maintained in excess of 215° F. in the first dryer section, the highest dryer temperature being about 240° F. on the dryer face, of the last dryers of this section.

Tests made on hot drink cups produced from this paper showed no penetration of the boiling coffee to. the glue line, upon long standing, and hence no objectionable odor or taste was noticeable in the coffee. The cups filled with hot coffee did not soften nor distort as do the present-day hot drink cups, and the hot drink cup stock paper made is significantly improved over the paper that is made for this purpose today.

Further tests established the fact that this unusual hot drink cup stock is likewise highly resistant to penetration by boiling tea and chocolate, and its abnormal resistance to water penetration establishes it as a superior product to cold drink cups as made today, which are generally wax-coated to increase their resistance to water penetration. As in common with all other machine production runs made by the practice of this invention, the sheet formation was noticeably better and closer than similar types of sheets made by conventional procedures.

EXAMPLE 4

This example relates to the machine-production of an unusual food packaging material, having extremely high resistance to penetration by food acids, as lactic, citric, malic, and the like, and having also a greater structural strength and a closer formation than the present-day materials used for this purpose. This unusual material has such abnormally high resistance to penetration by food acids, that it may be used in an unwaxed or uncoated condition, as the base material from which liquid or solid food containers may be made, such as milk, cream cheese, ice cream containers, and the like.

The instrumentality used in this machine production was a conventional five-cylinder board machine in an eastern mill, having a hard water supply. The board machine was completely equipped, having three primary presses and, in addition, an extraction roll ahead of the first press, to facilitate the removal of the maximum amount of water from the formed web before the initial press roll action had taken place, and thus make possible the production of board products of high density.

The driers were four feet in diameter, and arranged in three vertical sections, six driers high, each section containing eighteen such driers. The machine was further equipped with a hot air recirculating system in the drier sections, which materially helped in the drying of heavy and high density board.

The machine was also equipped with two calender stacks, the wet stack containing five rolls and the dry stack containing seven rolls. The wet stack had two water boxes and the dry stack was equipped with five steam heated rolls which were used only when a water finish was applied.

All pulp was processed in Holland type beaters of 1,000 pound capacity, there being six such beaters available. From the beaters, the stock was dumped to the beater chest, pumped from there to the Jordan head box; thence to a large Imperial Jordan, and thereafter, the stock flowed through a bank of Vortraps in series with the flat screens of the five-cylinder machine, thence to the cylinder head boxes.

For the purpose of this machine run, two of the mill beaters, No. 1 and No. 6, were furnished with 1,000 pounds, on a bone dry basis, of a fully bleached sulfate pulp, made from northern spruce and having about a 92% alpha-cellulose content. The beating cycle had been predetermined to be such that the fibers were to be drawn out and actually hydrated, not cut, to develop an optimum shrinkage factor of about 12% on drying, coincident with a minimum reduction in measured freeness. The initial freeness of the stock was 875 Schopper, the initial shrinkage factor, 6.87%.

At the end of a seven-hour beating cycle, using a light 5 beater roll action for the first three hours, and gradually lowering the beater roll during the last four hours, the finished freeness was 755 Schopper and the fiber shrinkage 11.82%.

At this point exactly 0.50%, on a solids basis, of the 10 cyano-aldehyde condensation reaction product, heretofore described, was added to the beater directly ahead of the roll to insure a rapid mix, a 10% solids, colloid solution being used, and the activator was reacted with the beaten pulp for thirty minutes at 90° F., the beater roll 15 being raised throughout all fiber chemical processing cycles. Thereafter, exactly 3.00%, on a solids basis, of the special ammonia-rosin complex, previously described, was added as a 10% solids dispersion and, at 140° F., and reacted for 10 minutes with the activated stock. 20 Then, exactly 0.50%, on a solids basis, of a cationic wax dispersion, previously described, was added and, likewise reacted with the treated stock for 10 minutes, and finally exactly 0.50%, on a solids basis, of a cationic dispersion of polyvinylethylether, heretofore described, was added 25 and also reacted with the treated stock for 10 minutes. At this point, an examination of the beater stock showed a crystal clear liquid phase, with no evidence of any additament being present therein. The so-processed stock suspension was then adjusted to a pH value of approxi30 mately 4.3, using a 10% solution of papermaker’s alum for this purpose, about 5% alum solids being required.

The finished stock was then dumped to the beater chest, and thence pumped to the Jordan head box and thereafter, flowed through the Jordan, the Vortraps, and the 35 flat screens to the machine head boxes. A very light jordaning was given the stock, the freeness thereafter being 745 Schopper, and the shrinkage factor remaining unchanged at 11.82%.

The machine speed was 220 f.p.m.; the machine trim 40 was 64; the board made was an exceptional product, as is evidenced by the test data detailed below. Throughout the machine run, no operating difficulties were encountered, the sheet formed better than normal, and was much closer in formation, there were no cylinder blows, 45 ply adhesion was excellent, and there was a total absence of foam, retention of additament material was substantially complete.

Physical test data on board made

Basis weight 24 x 36—500 ________________ 222.25

Average caliper____________________inches— 0.018

Average density 12.34

Average bursting strength, sq. in. 241

Elmendorf tearing strength, MD 603

Elmendorf tearing strength, CD__________ 847

Total Elmendorf tearing strength 1450

Tensile strength 1 width, MD 218

Tensile strength 1 width, CD 45

Elongation, MD____________________percent—3.75

Elongation, CD______________________do 14.25

Additional test data on board made

Samples were obtained representing the best type of food packaging board available, as made by present-day 65 procedures. These samples were subjected to drastic breakdown tests in parallel with samples of the board made by the practice of this invention. The bursting strength in pounds per sq. in. of the normal board was 89#, as compared to the 241# bursting strength per sq. 70 in. of the board of this machine run. The total Elmendorf tearing strength of normal board averaged 850 grams tear, as compared to 1450 grams tear of the board of this machine run, but the differences of greatest significance were the almost unbelievable differences in the 75 ability of the two types of board to withstand penetration

3,016,325 to 20 tons per hour. From the beater chest, which was equipped with several horizontal type agitators, the stock was pumped to the Jordan head box, and, thereafter, passed through the Jordans—there being three Majestic Jordans connected in series—and discharged from the last Jordan to the machine chest flow box, where dilution water and chemicals were added, prior to dropping the stock to the machine chest, where the consistency averaged about 3.00%, the temperature approximately 124° F. and the time of contact from 15 to 20 minutes, dependent upon machine production. From the machine chest, likewise equipped with horizontal type agitators, the stock was pumped to the finishing Jordans, consisting of two Majestic Jordans connected in series, and after passing through these Jordans, the stock was discharged into a 30 line, dilution water added to reduce the consistency to between 0.50% and 0.70%, prior to the stock flow to a bank of fifty Vortraps, connected in parallel, and thence to the fan pump of the paper ma20 chine, on the suction side of which one or more chemicals could be added in either solution or dispersion form.

The fan pump, a 30 centrifugal pump, discharged directly to a Deculator unit of 15,000 gallons per minute flow capacity, which was used for the purpose of deaerating the stock. From the Deculator unit, the stock flowed under pressure to the high speed head box of the paper machine, the temperature in which maintained at about 132° F., the consistency averaging 0.66%. The processed stock then flowed to the 54 x 34 mesh forming wire on which the complex cellulose-chemical complex water laid web was made. The machine was equipped with a dandy roll having a steam shower, nine suction boxes, and a suction couch roll; three primary presses; and one smoothing press, the presses being electrically controlled and operated by means of hydraulic pressure to any desired roll pressure. The dryers were five feet in diameter and arranged in four horizontal sections, the first section consisting of 38 driers, the second section having 20 driers, the third section having 20 driers, and there being a fourth drier section between the first and second calender stacks, consisting of 4 calender driers. A tub size unit and press were located midway between the second and third drier sections, the press roll likewise being electrically controlled, and operated by means of hydraulic pressure.

The first calender stack consisted of seven rolls and was equipped with four water boxes, to impart a water finish to both sides of the sheet. Between the calender stacks, the paper passed over the 4 calender driers, thence to the finishing calender stack, consisting of 9 rolls, the middle 5 of which were steam heated to insure a complete drying of the tub sized and/or water finished paper. Directly over the calender drier section and finishing calender stack was an arched shaped hood made up of sectional units of Calrod type radiant heaters, which were thermostatically controlled to give any degree of radiant heat required to insure a uniform moisture content in the finished paper web passing thereunder. Thereafter, the conventional reels completed the equipment of the ma60 chine proper, the rewinding, slitting and sheeting of the paper being done in a completely equipped finishing room.

For the purpose of this machine run, two stainless steel tanks of 300 gallons’ capacity each, equipped with high speed lightning type mixers and interconnected through ⁵ pipe lines and valves through a 2 centrifugal pump, were used to prepare the 10% solids colloid solution of the fiber activator, a complex reaction product of a cyanamid derivative and formaldehyde previously described. This was added to the stock in the continuous beater by being pumped through al rotameter to a distributor header, i.e., a 116 pipe in which were drilled Vs” holes on 1 centers the entire length of the pipe, which spanned the distance between the beater side and the midfeather. The rotameter unit was calibrated in by a 20% lactic acid solution at 75° F., under varying hydrostatic heads, as detailed below.

For example, under , a hydrostatic head of 100 centimeters, the normal board resisted lactic acid penetration for from 3 to 5 seconds. Under the same hydrostatic 5 head, at 100 centimeters, the board made by the practice of this invention resisted lactic acid penetration for 48 minutes.

Under a hydrostatic head of 40 centimeters, normal board resisted lactic acid penetration for 6 minutes, and, io under the same conditions of test, the board of this machine run resisted penetration for 200 minutes.

Samples of the board of this machine run were subjected to further tests. Tests were made on a circular area of board, 1% inches in diameter. Throughout the 15 test period, the specimens were subjected to the pressure of a 100 centimeter column of milk. The temperature during the time of test was from 70° to 75° F. No precautions were taken to prevent the milk from souring, so the test area was subjected to the action of sweet milk for 1-2 days, and sour milk for the balance of the period.

At the end of seven days, under the test conditions as above described, there was no leakage nor seepage of the milk through any of the processed board samples, conclusively demonstrating that the board of this machine 25 run is completely resistant to penetration by milk, even when under pressure conditions considerably higher than would be encountered in practical usage.

Similar tests on this board were made using water at 75° F. in place of the milk. At the end of 60 days, there 30 was neither leakage nor seepage of water through the board, convincingly demonstrating that board made by the practice of this invention is abnormally resistant to penetration by water, even under pressure conditions much higher than would normally be encountered. 35

A number of attempts were made to determine the Cuprammonium viscosity of the processed fibers comprising the cellulose-chemical complex web of this board, but repeated experiments showed that the board was no longer soluble in Cuprammonium solutions. Obviously, 40 then, a significant modification of the cellulose fibers has been effected by the practice of this invention, and a truly remarkable cellulose-chemical complex web has been actually produced on a conventional paperboard machine. 45

EXAMPLE 5

This example relates to the paper machine production of a material suitable for hot drink containers and other food packaging or dispensing uses. It differs radically 50 from the preceding examples in that this production was effected in a continuous operation, the fibrous suspension being both mechanically treated and chemically processed while in a continuous flow from the slush pulp tanks in the pulp mill to the finished product at the dry end of 55 the paper machine.

The chief instrumentality used in the production of this cellulose-chemical complex web was a completely modern Fourdrinier machine, trimming 200 and ranging in speed from 400 to 800 f.p.m., dependent upon the weight and type of product made. The machine was electrically controlled throughout, as were all of the primary fiber processing units.

Slush stock from the pulp mill flowed to a continuous beater of about 2,500 pounds’ capacity, the pulp entering at the head of the midfeather and being discharged in back of the roll to the beater chest flow box, where dilution water was added, prior to dropping the stock to the beater chest. The slush stock temperature ranged from 160° F. to 120° F.; the consistency averaged about 70 6.00%. The stock was diluted to about 4.00% consistency at the beater chest flow box, the temperature being maintained at about 120° F., contact time in the beater chest varied from 30 to 40 minutes, dependent upon machine production, which normally ranged from 75

3,016,325 ²⁵ .

gallons flow per minute. The specific gravity of the 10% solution of fiber activator was 1.051 at 75° F.

This point of addition insured a good mixing of the fiber activator with the beater stock as the mixture passed under the roll, as well as further good mixing in the beater chest flow box, and added mixing in the agitator equipped beater chest. The time of reaction of 30 minutes minimum and the average temperature of 120° F. further insured a complete reaction.

The dispersion of the special ammonia rosin complex, previously described, was initially effected in a 500-gallon stainless steel tank equipped with a high speed lightning type mixer, and supplied with water at 160° F., through an Abernathy steam injector system, which was thermostatically controlled. The dispersion was initially made at 20% solids concentration at 160° F., and when a complete dispersion was effected, the tank contents were pumped through a 2 centrifugal pump to an 8,200 gallon storage tank, dilution water added at 160° F. to bring the finished dispersion to a 10% solids content. This large tank was filled by an almost continuous operation of the 500 gallon mixing tank unit, and having been filled, the tank contents were continuously cycled through the tank by means of a 2 centrifugal pump and suitable piping connections. From this large storage tank, the ammonia-rosin complex dispersion was pumped through a 2 centrifugal pump to a constant level flow box equipped with an overflow line back to the storage tank and a 2 discharge line from the side of the tank, to a 2 rotameter unit, calibrated directly in gallons flow per minute, and discharging into the machine chest flow box; where good mixing was secured, which was later supplemented by agitation in the machine chest. The minimum time of contact in the machine chest was 15 minutes, the temperature averaged 124° F. and the consistency was about 3.00%. These conditions insured the completion of the reaction of this phase of operation.

The papermaker’s alum solution used to adjust the pH value was made up on the basis of 5# of alum solids per one gallon of solution. This solution was made up in two 1,030-gallon stainless steel tanks equipped with high speed Lightning type mixers, from which tanks the alum solution was pumped through a 2 centrifugal pump to a constant level flow box, with an overflow line back to the alum tanks, and a discharge line from the side of the tank to a Wz rotameter unit, calibrated directly in gallons flow per minute; the rotameter discharging into the suction side of the 30 fan pump. Stock consistency at this point averaged about 0.66%, the temperature was about 130° F., and the time of contact for the pH adjusting phase was approximately one minute. This time was satisfactory, as the dilution water added ahead of the fan pump consisted largely of machine white water from the wire pit, at about the pH value desired in the machine head box. Having established these points of addition as described, and the methods of preparing and metering the reactants, the actual operation of the practice of this invention became relatively simple and fully automatic as detailed below.

Machine production was determined to be 32,000 pounds per hour, at a speed of 455 f.p.m., and with an approximate flow of stock to the machine head box of 15,000 gallons per minute.

The gallons flow per minute of the 10% solids fiber activator colloid solution was set at 3.3 g.p.m. to give an addition of 0.50% activator solids on fiber solids in the continuous beater, through the distribution header and metering system previously described. The power consumed by the beater roll during the run was 115 amperes at 440 volts.

The amount of ammonia-rosin complex solids added each hour was 1,280 pounds, giving a 4.00% solids addition on fiber solids. This was added through the rotam-. eter feed unit, as described, at the machine chest. flow box, the gallons flow per minute of the 10% solids dispersion being set at 26 g.p.m. throughout the run.

The amount of alum solids added each hour was set at 1,020 pounds, this being the amount that adjusted the 5 running pH of the wire pit water to 4.0. The alum feed rotameter was set at 3.4 gallons flow per minute to give this addition, which amounted to approximately 3.2% alum solids, on fiber solids.

No operating troubles were encountered during the 1θ machine run. Foam formation was noticeably less than in normal operation. Sheet formation was noticeably improved and closer than in regular production. The cellulose-chemical complex web dried more rapidly than normal paper, and, as a result, the running speed of the 15 machine could be increased by at least 10%. The pH level at the wire pit remained constant during the run. The sheet produced was markedly superior to normal production, in structural strength, formation and abnormal sizing values, as shown in the detailed test data 2θ below.

The most important operating factors of this machine run are detailed below:

2½ hours.

32,000 pounds per hour

455 f.p.m.

200.

210#—24 x 36—500.

0.0156.

13.0.

roll load__________ consistency________ temperature_______ chest consistency chest temperature

115 amperes

6.0%.

120° F.

4.0%.

120° F.

at 440 V.

Running time_______________

Production ________________

Machine speed______________

Machine trim______________

Average basis weight________

Average caliper____________

Average density____________

Activator feed to continuous beater 3.3 gallons/minute of a 10% solids solution equals 0.50% solids addition on fiber solids.

Beater Beater Beater Beater Beater

Contact time beater chest averaged at 35 minutes. Average Majestic Jordan loadings (discharge line from beater chest):

# 1 Jordan_____________ # 2 Jordan_____________ # 3 Jordan_____________

Rosin-ammonia complex added at machine chest flow box on basis of 1,280 pounds solids per hour required rotameter feed of 10% solids dispersion of 26 gallons per minute—4.0% solids addition on fiber solids. Stock consistency at machine chest flow box___________

Stock temperature at machine chest flow box____________

Contact time in machine chest averaged of 15 minutes.

Average Majestic Jordan loadings (discharge from machine chest):

# 4 Jordan______________ # 5 Jordan_____________

Power load on machine fan pump at 15,000 gallons/minute discharge to Deculator equals 300 amperes at 440 volts.

Average pH value of water in head box ________________

Average consistency at machine wire pit.__________________ amperes, amperes, amperes,

3.0%.

124° F.

amperes, amperes,

0.66%.

4.0.

440

440

440

440

440 volts, volts, volts.

volts, volts.

3,016,3^5

Average stock freeness at machine head box was 845 Schopper.

Alum feed to suction side fan pump based on alum solids per hour was 1,020 pounds, required a rotameter feed of alum solution of 3.4 gallons per minute, equals 3.2% alum solids addition on fiber solids.

Effective roll pressure on 1st press------------------- 680#.

Effective roll pressure on 2nd press 800#.

Effective roll pressure on 3rd press 750#.

Effective roll pressure on smoothing press______ 625#.

Steam pressure #1 drier section 60#.

Steam pressure #2 drier section ---------- 65#.

Steam pressure #3 drier section------------------85#.

Steam pressure calender drier section___________-. 35#.

The physical test data on the paper made is detailed below:

Basis weight 24 x 36—500________pounds.. 210

Average caliper----------------------inch— 0.0156

Density________________________.___________13.4-(Moisture -------------------------percent—6.5

Average bursting strength----pounds/sq. in... 108 35

Average porosity—100 cc. Gurley___.inches..102

Elmendorf tear strength, MD______________ 468

Elmendorf tear strength, CD______________ 540

Stiffness—Tabor, MD _163

Stiffness—Tabor, CD ___________________;______83

Vanceometer ______________;________________ 39

Printability ---------------------—______ Excellent

Brightness G.E. ____________________________75.7

Resistance to boiling coffee under 7 hydrostatic head -------------------------minutes__368

At the completion of this run of processed paper, production was continued in the normal manner in order to secure comparative data.

The test data on normal paper made one hour after the completion of the processed run is detailed below.

Basis weight 24 x 36—500 _______.pounds—202

Average ca’iper------———inch— 0.0157

Average density_______________ 13

Moisture-------1------------------percent— 5.355

Average bursting strength —pounds/sq. in— 86

Average porosity, 100 cc. Gurley______inches__80

Elmendorf tear strength, MD 448

Elmendorf tear strength, CD____ 492

Stiffness—Tabor, MD _________ 16060

Stiffness—Tabor, CD 80

Vanceometer________________I33

Printability Good

Brightness, G.E. 75.8

Resistance to boiling coffee under 7 hydrostatic65 head —_—----------:---------minutes__12

The paper made by the practice of this invention resisted penetration by boiling coffee for 6 hours and 8 minutes, under pressure conditions greater than would 70' be encountered in practical usage. On the other hand, the normal paper, under the same test conditions, resisted penetration by boiling coffee for only 12 minutes. The paper made by the practice of this invention is about 30 times as resistant to penetration by boiling cof- 75 fee as is the normally made product and is indeed an abnormal product, unequalled as a base material for the production of hot drink containers. The processed paper retains substantially all of its original stiffness, when a cup made of it is filled with boiling coffee, whereas, a cup made from the normal paper product, rapidly softens and becomes deformed under the same conditions. The processed paper has a substantially higher bursting strength in pounds per square inch than does the normal product, e.g., 108# as compared to 86#. This added bursting strength of the processed paper enhances the utility value of this material as a hot drink container, as is understandable. In all other respects, the structural properties of the processed paper were superior to those of the normal product, even though the normal product as made and tested is considered a satisfactory paper for this specific use.

EXAMPLE 6

A blended pulp furnish consisting of 75% of bleached hardwood kraft pulp and 25% of bleached softwood sulfate pulp was furnished to the laboratory dynopulper, and cycled therein for about thirty minutes.

Thereafter, the thoroughly blended and partially beaten furnish was transferred to the laboratory beater at 690 Canadian Standard freeness and an oven dry consistency of 2.52%. The beater roll was adjusted to a hard beating action and then, 3.0%, on a solids basis, of a 10% active solids content, cationically reactive, chemically reactive, colloidal system of tetramethylolacetylenediurea was added and the hard beating continued for 20 minutes. The Canadian Standard fineness was then checked and found to be 659.

At this point in processing, and with the beater roll still adjusted to a hard beating action, exactly 3.00%, on a solids basis, of a cationic reactive, colloidal system, of a condensation reaction product of urea and formaldehyde, having an amino substituent group in its structure, was added and reacted for 5 minutes, the beater roll remaining in the hard beating position.

Then, 5.00% of papermaker’s alum, on a solids basis was added in the form of a 10% solution, and hard beating continued for an additional 5 minutes.

Thereafter, exactly 1.50%, on a solids basis, of the ammonia rosin complex previously described, was added as an 8% solids dispersion and, with the position of the beater roll still unchanged, beating was continued for 5 minutes. Thereafter, the Canadian Standard freeness of the treated stock was determined to be 542; the oven dry consistency 2.58%; and the pH value of the treated fibrous suspension 4.18.

Hand sheets were then made, using a 60 mesh forming wire, a two-rbll rotary press, equipped with a standard mill type press felt, arid a drum dryer equipped with a dryer felt and operated at 25# steam pressure, the drying cycle being between 2 and 3 minutes.

The hand sheets so made had a noticeably close formation and were clear and free from either resin or fiber clots. The hand sheets made averaged 51.75# basis weight, 24 x 36—500, and the average Mullen being 60.1#, an unusually high strength value for this fiber furriish.

The sheets were distinctly novel, in that they were very porous, and yet abnormally hard sized, and, as such, would be an ideal coating base stock, as the sheet can breathe freely and yet is abnormally resistant to penetration by ink fluids at 120° F.

The Gurley densometer value for these sheets averaged 10.5 seconds per 100 cc. of air flow; yet the resistance to standard ink penetration at 120° F. averaged 9,300 seconds, as compared to about 200 seconds for a conventionally sized sheet of the same weight.

This example establishes the fact that drastic mechanical treatment of the fibrous material can be carried on coincidentally with chemical fiber processing, by the

3,016,325 practice of this invention, without undue loss of the unusual strength and barrier properties that are invariably characteristic of the cellulose-complex webs resulting from the fiber processing procedures of this invention.

EXAMPLE 7⁵

This example relates to the production of a food packaging board of greater than normal structural strength and of unusual barrier properties. Heretofore, in the production of such material, it has been customary to jq use a small percentage of paraffin wax in order to obtain a high resistance to lactic acid solutions of about 20% acid content. Generally, however, as the wax content was increased, the structural strength of the board decreased materially; the board stiffness was seriously af- 15 fected; and it became increasingly difficult to produce a well formed and uniform sheet. In this example, however, a large percentage of a novel type of wax is used and yet the board made has a greater structural strength and stiffness than a similar board, made from the same 20 but untreated fiber furnish.

The laboratory beater was furnished with 100% of Bleached Harmac kraft pulp and the stock reduced to a Canadian Standard freeness of 606, using a 120-minute beating cycle, the beater consistency being about 2.60%. 25 Thereafter, exactly 1.50% on a solids basis, of a complex reaction product of dicyandiamide and formaldehyde heretofore described was added, as a 10% solids content colloidal dispersion, and beating continued for 65 minutes, at the end of which time the Canadian Stand- 30 ard freeness had been reduced to 510, the consistency being unchanged.

Then, exactly 3.00% on a solids basis of the rosinammonia complex, previously described, was added to the activated beater stock and reacted therewith for 15 35 minutes, after which exactly 1.50% on a solids basis of a water-isopropanol dispersion of a high-melting point microcrystalline petroleum wax was added, and the beater circulated for an additional 10 minutes. Then, a 10% solution of papermaker’s alum was added to adjust the 40 pH value of the treated beater stock to 4.0, approximately 5.0% of alum solids being required. Hand sheets were then made using a 60 mesh forming wire. The sheets were dried on a rotary drum dryer, equipped with dryer felt and operating at 30# steam pressure. Thereafter, 45 the dried web was tested with the results hereafter detailed.

A set of control hand sheets having no chemical treatment, were also made, using the same pulp furnish, the same beating cycle and the beaten stock so prepared had 50 a finished Canadian Standard freeness of 505. The test data relative to these control sheets is likewise hereafter detailed.

Processed Control 55

Sheets Sheets

Basis Weic^t 24 x 36—500...................

Average Caliper-----------------——------——

Average Bursting Strength, #/sq. in----------Average Elmendorf Tear Strength------------Average Porosity Gnrley-secs./100 cc---------Tesist anse to Standard Test Ink @ 120° F----^esistanse to 20% Lactic Acid, minutes. .....

resistance to water @ 75° F------------------resistance to milk @ 75° F____________________

222 0.0172 300+ 1,072

185 (^{* 1})

1.650 (²) (²)

228 0.0175

200 960 188

0

0 ³⁰