Web printing paper having coldset suitability

The invention relates to a material suitable for printing with cold-set offset printing inks, Web printing paper coated according to the preamble of claim 1. The invention further relates to the use of such a paper.

Newspapers are now printed primarily in offset application, namely using so-called. Coldset inks, which are unlike heatset offset printing inks exposed to dry no heat, but dry only in that the emulsion water of the ink as well as the contained in it oil in the print medium, namely paper, chip off as quickly as possible, the color carrier of the ink will remain on the paper surface. In addition, here takes place oxidative drying.

Although the printing quality with increasing smoothness of the print carrier better and the ink consumption is lower, higher smoothness of a paper having a generally lower absorbency result, whereby the speed of setting the Farbemulgatoren is slowed down, which in turn causes smearing on the guide elements of the printing machine and for depositing leads copy stack. On the other hand, a too high absorbency an increased penetration of the inks into the paper, which means a bad point prior to and showthrough of the printed image resulting in faulty expression, on the back side. Standard newsprint satisfy the conditions for a sufficiently rapid drying coldset inks, known the quality of the printed image is limited to newsprint. Standard Excessive newsprint is an uncoated, so-called. Nature paper. Its pore volume is therefore not covered by a coating which could hinder the absorption of the Druckfarbenemulgatoren.

Rotary presses for newspaper printing are utilized usually only for a limited time of the day. It would therefore be useful to prove such expensive equipment while the available idle times with other print jobs, especially in the commercial sector. For such contracts, it was loose inserts or the like, in general, but in particular called for a higher quality of the printed image in multicolor printing, than is possible on a standard newsprint. There has been no shortage of attempts and considerations, so-called for the said purpose. To provide improved newsprint papers available that in the field of quality of SC paper (super calandered), namely hochsatinierter papers, such as those used for the heatset offset printing, or as coated papers, even in the field of LWC papers (low weight coated) penetrate. The experiments so far it has been, however, not destined to gain market acceptance.

EP-A-0377983 describes a coated newsprint whose coldset suitability is to be achieved in that the coating pigment contains a certain minimum percentage of needle-shaped pigments and total at least a specific oil absorption value. It is not known that such a paper has been found on the market entrance. Acicular pigments such as satin white, precipitated calcium carbonates and delaminated or structured kaolins, as proposed in the publication, are very expensive in general. In addition, they require a high binder demand, which increases the manufacturing costs in addition, because of their structure.

The invention has for its object to provide an economically producible, Web printing paper coated available, which is suitable for printing with coldset inks, optically settles from the normal newsprint and can also be processed with the print speeds as the offset newsprint or to the designated machines are common.

This object is basically achieved on the basis of the subject matter of EP-A-0377983 by a web printing paper with the characterizing features of claim 1.

In of the priority European patent application 196 01 245.7 a suitable for coldset offset printing Web printing paper coated was defined by the type of paint composition substantially, which in turn, determines to a certain level of water absorption capacity of the paper surface than the surface wettability, which for the printing suitability in coldset offset seems to be crucial. Another important property for coldset suitability is the ink absorption of the paper.

While limits on the water absorption capacity, has determined proven surface wettability or as immediate penetration substantially as generally valid for the marking of a coated web printing paper in the most essential types of printing machines, which operate on the coldset offset printing process, the ink absorption than partially proved depending on machine type. Example, it was noted in print Try that with certain types of machine such as a too slow Farbwegschlagen but just too fast Farbwegschlagen can not result in the surface of the paper to pigment deposits on a printing subsequent rolls. Now can the Farbwegschlagzeit affect, among other things through the structure and composition of the coating pigment in a way that on the other hand has only little effect on the water absorbency of the paper. A comprehensive characterization of coldset suitability of coated printing papers alone by the bar composition therefore encounters difficulties. In the present case the coldset suitability of a coated web printing paper is therefore primarily characterized by its water absorption capacity and in addition by the color lift.

To the offset method to be ever printability, a paper must additionally have conventionally a corresponding Oberflächenrupffestigkeit. For this purpose, there are certain test methods, but which have the disadvantage that the evaluation of the test results are generally only takes place after visually experience. By comparison, however, is objectively readily determined whether a questionable paper regarding the lifting test having this offset suitability or not. To determine the pick resistance is used, for example, the sample printing machine system Dr. Dürner who Prufbau Dr.-Ing. Herbert Dürner in Peissenberg. This unit processes the printing process to be imitated. When Trockenrupftest ink is transferred in a printing unit with increasing printing speed on a piece of paper. The pressure exerted on the paper surface forces increase with increasing printing speed. Therefore, it can be judged on the printed paper strip, at about which pressure speed, the surface of the sample strip will no longer be withstood the pressure drain. When Naßrupftest which mimics particularly the offset process, the test strip is wetted in a first pressure passage and printed in a second run at a constant printing speed. The printed image on the test strip can detect whether the surface binding of the paper is sufficient exposure to moisture during printing.

The immediate water absorption of a paper surface, determined as the surface wettability is with the device "FIBRO 1100 Dynamic Absorption Tester" the company FIBRO System AB, Stockholm, has been determined. In this measurement method, a liquid drop, here distilled water, brought to the sample surface and the edge angle of this drop is measured after certain times. In this specification, the contact angles are given by 2 sec. Brief details of the test method are attached as Exhibit A of this specification.

An introduced after the priority date, substantially the same paper property characterizing, but experience to date seem more reproducible test method to determine the direct water absorption of a paper sample is that the sample is immersed under defined conditions in water and the change of the ultrasonic transmission of this system measured becomes. In that regard, other parameters are held constant, indicates the change of the ultrasonic transmission a measure for the penetration of water into the paper sample from. The reproducibility is even better because in this test a larger sample area is detected.

For measuring the immediate water absorption or penetration of a paper sample by means of ultrasound transmission, the Dynamic Penetrationsmeßgerät DPM 31. The test method serves 27 of the company emco Electronic Measurement and Control GmbH in 04347 Leipzig, Gorkistraße underlies the equipment specifications and operating this company as of 03.13.1995 , is measured, the variation of the ultrasonic transmission value, on the basis of the measured value of the sample at the start of measurement, which is equal to 100%, versus time. Indicated is the respective time of measurement as a percentage of equal to 100% set the initial value. Basically This is a dynamic test in which a curve of transmission characteristics is plotted against time. This curve falls for consideration here only paper types steeply, then turns around and approaches for measuring times above 6 sec more or less asymptotically a specific transmission value. For the behavior of the paper substantially the affinity for water at the first moment is critical, which is why the measured values ​​after a time of 1 sec are given for the purpose of this description. have certain significance for the assessment but also the measured values ​​after 3 sec, a time at which the curve steep drop pivoted around approximately in the horizontal and this results in a certain saturation point. This test method is referred to as emco test and the values ​​are expressed as percentages (percent residual transmission, starting from 100%).

A prerequisite for coldset suitability of a coated web printing paper that the contact angle determination gives a value of <70 ° with the FIBRO test after 2 sec. Better results are achieved when the contact angle after this time is <55 °. Standard newsprint has after 2 sec, for example, to a value of only about 42 °. Such uncoated paper has a high wetting behavior that of a coated paper, however, usually can not be achieved. Measured by ultrasound transmission after emco test the suitability of a coldset paper is given if after 1 sec to a value of 85-25% is reached, but preferably a value in the narrow range of 70-30%.

After a measuring time of 3 sec papers according to the invention in emco test generally have values ​​in the range of 55-30% and in a narrower range of values ​​40-30%.

The angle of the boundary determining parameters after FIBRO test was taken as a coarser classification the key characteristic of the claims. In the ultrasonic transmission determination after the Emco test, although it is a formal another parameter, however, is so far discussed the task solution described herein, practically characterizes the same characteristics of the paper. There the claimed limits for the Emco test are therefore independent of the feature of the edge angle determination viewed solely as the invention constitutive for himself behind the FIBRO test.

The additional feature for identifying the paper of the invention, which, however, refers not only to the printability such as coldset but also on the processability of the paper in the corresponding press types, is its color lift. To determine the Farbwegschlages is a modified in the company of the applicant absorption test, also using the multi-purpose sample printing machine system Dr. Dürner who Prufbau Dr.-Ing. Herbert Dürner, Peissenberg, used. When absorption test, a test print with a standard printing color is generated under defined conditions, is brought, after a defined time under pressure with a counter paper in contact. The reprinted on the counter paper ink intensity is measured with a densitometer. Information in the following are the densitometer of the counter pressure after 30 sec. Brief details of the test method of this description are attached as Annex B.

The Farbwegschlagwerte of paper of the invention should be 1.1 to 0.25. With values ​​in the narrower range 0.8 to 0.3, very good results are generally achieved.

Fine-particle pigments in the coat composition generally accelerate the ink drying (reduction of absorption time, expressed by a lower densitometer value) and water absorption. The expert has therefore to influence it through the selection and mixing of the pigment particle size in hand, both dimensions according to the invention. Is it possible for a given printing press assembly to misprint a paper having very fast Farbwegschlagzeiten, is chosen as the binder for the coating color preferably highly active synthetic binder, preferably in combination with polyvinyl alcohol. Thus, the binder for such a coating composition from 4.5 to 5.5% synthetic binder and between 1 and 4% PVA, based on coating pigment, consist. If required a longer absorption time with the same water absorption capacity, this can be achieved by additional binder in the bar formulation, for example by addition of 0.5 to 1.5% carboxymethylcellulose (CMC), depending on the composition of the coating pigment. If the binder addition starch, added in the range of about 2-6 wt .-% for delaying Farbwegschlagzeit, this can also have an influence on the water absorption capacity. To obtain this, the fineness of the coating pigment must be adjusted if necessary. Another effective way to increase the water absorption capacity, is the addition of up to 25 wt .-% of a swellable pigment, preferably a sodium bentonite for coating pigment.

In total the binder content in the coating color 15 wt .-% should, based on the coating pigment, not exceed. The higher values ​​below this limit then come into question when used in addition to synthetic binders starch and / or CMC.

In the paper coating binder following types are generally used, their sequence indicating decreasing binding action: plastic dispersions (eg, styrene-butadiene, acrylate, styrene-acrylate), polyvinyl alcohol, protein or casein, starch. Highly active binders are the aforementioned plastic dispersions, also in combination with PVA. For certain binders, the addition of a crosslinking agent may be required. If you work in certain applications only with highly active, synthetic binders, can the total binder content below 11 wt .-%, based on coating pigment type preferably even below 9.5 wt .-%. PVA has in addition to its binding power nor the property, irreversibly smartly onto surfaces having a relatively inert reaction capacity, as is the case with the calcium carbonate used in the present invention. The binder proportions may be as follows:<tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Plastic binder</entry><entry namest="col2" nameend="col2" align="right">3-10 wt .-%</entry></row><row><entry namest="col1" nameend="col1" align="left">PVA</entry><entry namest="col2" nameend="col2" align="right">0 - 5. wt .-%</entry></row><row><entry namest="col1" nameend="col1" align="left">protein</entry><entry namest="col2" nameend="col2" align="right">0 - 5. wt .-%</entry></row><row><entry namest="col1" nameend="col1" align="left">Strength</entry><entry namest="col2" nameend="col2" align="right">0 - 5. wt .-%</entry></row><row><entry namest="col1" nameend="col1" align="left">CMC</entry><entry namest="col2" nameend="col2" align="right">0 - 2. wt .-%</entry></row></tbody></tgroup></table></tables>

The proportion of calcium carbonate in the coating pigment should be at least 50 wt .-%. Preferably, however, higher levels of at least 70 wt .-% are. It is quite possible that the entire coating pigment of calcium carbonate there. As extender pigments, however, also come up to about 20 wt .-% aluminum and up to max. 50 wt .-% of kaolin in question, as well as mixtures of these pigments. As already mentioned above, the properties of the coating color as well as the final stroke can be positively influenced if desired by the addition of an amount of a swellable layered silicate for coating pigment, in particular a sodium bentonite. Top however, the amounts of such pigments are limited, because through it the viscosity of the coating is greatly increased, a fact which can only be compensated by a lower solids content again so desired coating application volumes are no longer accessible. Practically useful therefore are additions of a sodium bentonite of up to 25 wt .-%.

With regard to the fineness of the coating pigment, so it will use for instruments for applications that allow a relatively fast Farbwegschlag, fine to medium fine coating pigments, while the pigment composition for paper, which should have a slower Farbwegschlag, may be on the rougher side. Overall, the proportion of pigment particles &lt;2 microns, should not go below 60 or 65 wt .-%. When a coating pigment contains a majority share of Calciumkarbonates whose fineness is only 60 wt .-% &lt;2 microns, an increase in the degree of fineness by adding finer extender pigments such as kaolin or aluminum hydroxide can be carried out. By default, can be used with a fineness of 70% &lt;2 microns, a calcium carbonate, which certain amounts of sodium bentonite or other waste pigment are added.

Incidentally, the coating colors used conventional additives such as up to 1.5 wt .-% melamine formaldehyde resin as a wet strength agent, up to 0.4% carboxymethylcellulose (CMC) as a solution, optical brighteners and / or chemicals for pH adjustment, such as NaOH contain.

Suitable for the invention and available on a large scale on the market, milled, natural calcium carbonates are, for example, the types C60 HS, C70 and C90 HS from ECC International. The quality C60 HS has a share of 63 ± 3 wt .-% &lt;2 microns, a maximum of 2 wt .-%&gt; 10 microns and a maximum of 0.01 wt .-%&gt; 45 microns. The quality C90 HS contains 90 ± 3 wt .-% &lt;2 microns, a maximum of 1 wt .-%&gt; 10 microns and a maximum of 0.01 wt .-%&gt; 45 microns. These qualities are delivered as slurries having a solids content of 78 ± 1 wt .-%. Another manufacturer is suitable Calciumcarbonatqualitäten Omya.

The coating colors according to the invention are processed in an aqueous slurry at a solids content of 30-65 wt .-% dry imaginary mass. As application processes both scraper coating processes such as Inverted Blade, Jet Flow and roller application devices such as the Massey coater and also film presses such as the film press Jagenberg, the speedsizer or metering size press of Beloit eligible. The paper according to the invention is therefore independent of the type of coating application process substantially, although one or the other application method can under certain conditions lead to a better result. As is known, the same doctor blade method, the paper surface and therefore lead to locally different thickness of coating applied, while roller coaters rather produce a uniform coating application, which for the Farbwegschlagverhalt can be positive s circumstances. Also of importance is a gentle coat drying can be, lest undesired binder migration phenomena impair the desired uniform microcapillarity of coating application.

In just coated papers are inventively dry imaginary line quantities with a basis weight of more than 4 g / m² and side applied to the base paper. Preferred surface-related masses of 7-12 g / m² and page, typically about 8 g / m² and side.

However, the invention is not limited to simply coated papers. It is also applicable to double-coated papers. Double bars are at a basis weight of at least 15 g / m² and side, typically 20 g / m² and side, wherein the coating composition is split about equally between the two line applications. Decisive for the inventive properties of the paper is obviously the top coat. When in this description of a coat application is mentioned, without this is referred to in more detail, it is meant for single-coated papers the sole coat application and double-coated papers usually the top coat. The precoat home double bar is always expressly stated in this description as such. The primer can have a different meaning from the topcoat composition.

It may be expedient, vorzuglätten the base paper before applying the single stroke or the primer coating, for example in a machine stack at the end of the paper machine, which can also be equipped with a so-called. Soft-nip.

The invention is not limited to the use of a specific base paper. So can be used with a significant proportion of recycled waste paper fibers, both wood-free as well as wood-containing base papers and such. So a woodfree base paper is suitable, for example, the entry for the paper production in dry imaginary shares about 78% cellulose, about 20% mineral filler, divided into 15% calcium carbonate, 2.5% kaolin and 2.5% talc, about 1% strength and about 1% other auxiliaries contains.

for reasons of cost alone, but wood-containing base papers are preferred which in addition contain a proportion of recycled waste paper fibers. Wood-containing base papers also report generally also printing advantages in, for example, a higher opacity. The fiber furnish for a wood and waste paper containing raw paper may, for example, based on dry imaginary total pulp from about 20% cellulose, 20% wood pulp and 60% waste paper pulp made. Based on the fiber material of the furnish may further comprise up to about 50% of mineral filler contained, which corresponds to a proportion of 1/3 of the material composition. As known, this filler in the production process is not fully in the paper, but comes partially in the process water.

When in this description of pulps as fibrous component is mentioned, it can involve all such materials that are commonly understood in paper technology with this expression, namely, for example, groundwood, thermomechanical pulp (TMP), chemo-thermo-mechanical pulp (CTMP), etc ..

Another important requirement for an acceptable printing result when printing a paper with cold-set inks in addition to a satisfactory drying of the ink, the dimensional stability of the paper. Since the absorption of the cold-set inks water also penetrates into the supporting base paper the line, this has an influence on the fiber bonding to each other and thus affect the dimensional stability of the paper. This influence is stronger compared to normal newsprint uncoated paper, as in a coated paper with a comparable mass per unit area of ​​the base paper as base paper for bar belongs only to a correspondingly lower mass fraction, ie, the base paper is thinner. The dimensional stability of a paper of moisture can be additives such as starch, improved. So it is common to a Rohpapiereintrag add about 0.5% starch. be prepared for papers, the so-called on open Fourdrinier paper machine or on. hybrid formers, in which an upper dewatering is brought together only after sheet formation on the wire thereto, and which have as a result of this manufacturing process a relatively favorable fiber orientation ratio, namely a transverse-to-longitudinal ratio of about 1: 2 up to 1: 2.5, the dimensional stability for their use in coldset printing method ranges from possibly already without the base paper at all starch is added. Because of the predominant fiber orientation in the direction of production, ie, the longitudinal direction of the paper, there are defects in the dimensional stability substantially in a transverse contraction, which is further increased by the paper pull in the processing machine.

Mass printing papers are economically produced nowadays only on very high-speed paper machines, called the current state of the art only. Use gap former in which the sheet formation is carried out in co-running gap of two screens. When produced on modern machines such papers, the transverse-to-longitudinal ratio of the fiber orientation is much worse and is in the range of about 1: 3 to 1: 4. This has a much smaller transverse stability such papers result. It has now been found in the invention that the dimensional stability can be affected positively by sufficiently produced in gap formers base papers when the Rohpapiereintrag more than 1%, up to about 2%, typically adding about 1.5% starch. The amazing thing is not the effect of starch on the paper, but in the fact that a paper with such a high intensity entry on a gap former can be produced at all, which was not previously thought possible. This has been achieved in the invention by a modified namely highly cationic starch. The surprising effect was that the addition of about 1.5% of starch to furnish about 1.4% were recover in the base paper, indicating a remarkably high retention of strength during sheet formation, without the higher starch addition amounts in the furnish remain without significant effect on the base paper and at best increase the waste water pollution and the cost. When you make trial run with highly cationic starch, the base paper was produced at about 1220 m / min without reducing the machine speed.

The question here papers of the invention, having the aforementioned characteristics, are particularly uncalendered or only very weakly calendered papers with Bekk smoothness values ​​between about 10 and 50 seconds. These are so-called. Slightly satin or matte grades. A high calendering the paper of the invention would reduce due to the relatively low binder proportion in line not only required for a printing aptitude pick resistance of the surface, it could be lost also demanded microcapillarity required for drying the cold-set inks.

In that regard, in this specification otherwise indicated, percentages, even if this is not expressly mentioned, always to be understood as percentages by weight. Furthermore, unless otherwise specifically indicated, the percentage as well as other quantities always refer to the dry imaginary component. In this context, the statement "oven" in an oven-dry state relates.

Following are embodiments of the invention.

example 1

On a high-speed paper machine with a twin (gap former) a base paper at a line speed of about 1200 m / min generated from the following furnish: <tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">Furnish raw paper</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">groundwood</entry><entry namest="col2" nameend="col2" align="right">12.3%</entry></row><row><entry namest="col1" nameend="col1" align="left">cellulose</entry><entry namest="col2" nameend="col2" align="right">13.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">wastepaper</entry><entry namest="col2" nameend="col2" align="right">40.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">filler</entry><entry namest="col2" nameend="col2" align="right">33.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">Highly cationic starch</entry><entry namest="col2" nameend="col2" align="right">1.5%</entry></row><row><entry namest="col1" nameend="col1" align="left">retention agents</entry><entry namest="col2" nameend="col2" align="right"><u>0.2%</u></entry></row><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="right">100%</entry></row></tbody></tgroup></table></tables><tables id="tabl0003" num="0003"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">Test data of the base paper</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">area based size</entry><entry namest="col2" nameend="col2" align="char" char=",">40.3 g / m²</entry></row><row><entry namest="col1" nameend="col1" align="left">filler</entry><entry namest="col2" nameend="col2" align="char" char=",">15.2%</entry></row><row><entry namest="col1" nameend="col1" align="left">Strenght closed</entry><entry namest="col2" nameend="col2" align="char" char=",">41.8 N</entry></row><row><entry namest="col1" nameend="col1" align="left">Breaking load crosswise</entry><entry namest="col2" nameend="col2" align="char" char=",">11.8 N</entry></row><row><entry namest="col1" nameend="col1" align="left">to fiber orientation along transversely</entry><entry namest="col2" nameend="col2" align="char" char=",">1: 3.5</entry></row><row><entry namest="col1" nameend="col1" align="left">brightness</entry><entry namest="col2" nameend="col2" align="char" char=",">73.5%</entry></row><row><entry namest="col1" nameend="col1" align="left">volume</entry><entry namest="col2" nameend="col2" align="char" char=",">1.538 cm³/G</entry></row></tbody></tgroup></table></tables>

example 2

The base paper according to Example 1 was coated with a coating application of the following composition: <tables id="tabl0004" num="0004"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="left">coating pigments</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">nat. CaC0₃ 95% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="right">80%</entry></row><row><entry namest="col1" nameend="col1" align="left">Al (OH)₃ 98% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="right"><u>20%</u></entry></row><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="right">100%</entry></row></tbody></tgroup></table></tables><tables id="tabl0005" num="0005"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="center">Binders and additives, based on the coating pigments</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Styrene-acrylate binder</entry><entry namest="col2" nameend="col2" align="char" char=",">10%</entry></row><row><entry namest="col1" nameend="col1" align="left">starch solution</entry><entry namest="col2" nameend="col2" align="char" char=",">3.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">CMC solution</entry><entry namest="col2" nameend="col2" align="char" char=",">0.25%</entry></row><row><entry namest="col1" nameend="col1" align="left">Melamine formaldehyde resin</entry><entry namest="col2" nameend="col2" align="char" char=",">0.8%</entry></row><row><entry namest="col1" nameend="col1" align="left">Optical brighteners</entry><entry namest="col2" nameend="col2" align="char" char=",">1.3%</entry></row></tbody></tgroup></table></tables>

The coating application had a basis weight of approximately 8 g / m² and side. On the finished paper the following measurement data showed:<tables id="tabl0006" num="0006"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">area based size</entry><entry namest="col2" nameend="col2" align="left">56.5 g / m²</entry></row><row><entry namest="col1" nameend="col1" align="left">Ashes after annealing at 600 ° C</entry><entry namest="col2" nameend="col2" align="left">35.3%</entry></row><row><entry namest="col1" nameend="col1" align="left">volume</entry><entry namest="col2" nameend="col2" align="left">1.18 cm³/G</entry></row><row><entry namest="col1" nameend="col1" align="left">Bekk smoothness top</entry><entry namest="col2" nameend="col2" align="left">22 seconds</entry></row><row><entry namest="col1" nameend="col1" align="left">Bekk smoothness bottom</entry><entry namest="col2" nameend="col2" align="left">15 seconds</entry></row><row><entry namest="col1" nameend="col1" align="left">FIBRO test contact angle after 2 sec.</entry><entry namest="col2" nameend="col2" align="left">58 °</entry></row><row><entry namest="col1" nameend="col1" align="left">Wegschlagwert at 30 sec.</entry><entry namest="col2" nameend="col2" align="left">0.42</entry></row></tbody></tgroup></table></tables>

The coldset qualifications, adequate ink drying of this paper in the practical test was satisfactory.

example 3

The base paper according to Example 1 was coated with a coating of the following composition: <tables id="tabl0007" num="0007"><table frame="all"><tgroup cols="2" colsep="1" rowsep="1"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="left">coating pigment</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">nat. CaC0₃ 90% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="right">100%</entry></row></tbody></tgroup></table></tables><tables id="tabl0008" num="0008"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="center">Binders and additives, based on coating pigment</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Butadiene-styrene binder</entry><entry namest="col2" nameend="col2" align="char" char=",">5.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">PVA solution</entry><entry namest="col2" nameend="col2" align="char" char=",">3.5%</entry></row><row><entry namest="col1" nameend="col1" align="left">Melamine formaldehyde resin</entry><entry namest="col2" nameend="col2" align="char" char=",">1.3%</entry></row><row><entry namest="col1" nameend="col1" align="left">Optical brightener</entry><entry namest="col2" nameend="col2" align="char" char=",">1.3%</entry></row></tbody></tgroup></table></tables>

The paper had the following surface properties: <tables id="tabl0009" num="0009"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">FIBRO test contact angle after 2 sec.</entry><entry namest="col2" nameend="col2" align="right">45 °</entry></row><row><entry namest="col1" nameend="col1" align="left">Wegschlagwert sec after 30th</entry><entry namest="col2" nameend="col2" align="right">0.50</entry></row></tbody></tgroup></table></tables>

The other test data corresponding to the paper of Example 2. The paper according to this example in the practical test an excellent coldset suitability pointed to a printing machine with an 8-printing tower.

example 4

The base paper according to Example 1 was coated with a coating color according to Example 3 only in differed from the coating slip that the coating pigment instead of a polyacrylate as a dispersant to a highly amine-containing cationic dispersing a cationic pigment slurry and a cationic plastic binder used for coating color preparation has been. For the final paper following Oberflächenmeßwerte revealed:<tables id="tabl0010" num="0010"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">FIBRO test contact angle after 2 sec.</entry><entry namest="col2" nameend="col2" align="right">50 °</entry></row><row><entry namest="col1" nameend="col1" align="left">Wegschlagwert sec after 30th</entry><entry namest="col2" nameend="col2" align="right">0.39 / 0.47</entry></row></tbody></tgroup></table></tables>

The printability of this paper also coldset was very good.

Example 5 (Comparative Example)

The base paper according to Example 1 was coated with a coating color of the following composition: <tables id="tabl0011" num="0011"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">nat. CaC0₃ 90% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="right">80%</entry></row><row><entry namest="col1" nameend="col1" align="left">Kaolin 80% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="right"><u>20%</u></entry></row><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="right">100%</entry></row></tbody></tgroup></table></tables><tables id="tabl0012" num="0012"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="center">Binders and auxiliaries, based on coating pigment</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Styrene-acrylate binder</entry><entry namest="col2" nameend="col2" align="char" char=",">9.5%</entry></row><row><entry namest="col1" nameend="col1" align="left">starch solution</entry><entry namest="col2" nameend="col2" align="char" char=",">7.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">CMC solution</entry><entry namest="col2" nameend="col2" align="char" char=",">0.25%</entry></row><row><entry namest="col1" nameend="col1" align="left">Melamine formaldehyde resin</entry><entry namest="col2" nameend="col2" align="char" char=",">0.8%</entry></row><row><entry namest="col1" nameend="col1" align="left">Optical brightener</entry><entry namest="col2" nameend="col2" align="char" char=",">1.3%</entry></row></tbody></tgroup></table></tables>

The substrate coated with the coating color paper had the following surface data: <tables id="tabl0013" num="0013"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">FIBRO test contact angle after 2 sec.</entry><entry namest="col2" nameend="col2" align="left">72 °</entry></row><row><entry namest="col1" nameend="col1" align="left">Wegschlagwert sec after 30th</entry><entry namest="col2" nameend="col2" align="left">1.11 / 1.19</entry></row></tbody></tgroup></table></tables>

The ink drying when printing with coldset color was wrong. This is already the surface properties expressed and was due to the high proportion of binder.

A similarly poor print result was also found in a paper whose coating application differed from the only way given above, that the coating pigment instead of 20% kaolin 20% Al (OH)₃ were used with 98% &lt;2 microns. Proportion and composition of binder were the same.

In particular, the test papers according to Examples 3 and 4 could be processed on coldset presses with 8-printing towers with normal production speeds, leading to a precise image reproduction with normal ink drying behavior. Simultaneously arose over newsprint a lesser ink consumption. The water flow was reduced. The higher compared with normal newsprint White led to a high-contrast print, which was comparable with the print quality of LWC matte qualities.

Here are four more embodiments. each a standardized base paper was used, as it is of the type according to the embodiment 1 for the test papers. This paper was coated with different coating colors. The coating applied was in each case 7 g / m² and side. The smoothness of the finished paper was about 15 seconds Bekk on the top and about 12 seconds Bekk on the bottom. All papers show both in the determination of the dry pick as well as in the determination de Wet Pick on top and bottom of the mark "1". They were therefore offset suitable in any case. Also in the following paper properties are given separately for the top and bottom of the paper. The relevant values ​​are separated by a slash, the value before the slash for the paper surface and the value after the slash for the paper base applies.

example 6

The base paper was coated in this example with a coating color, which had the following essential elements: <tables id="tabl0014" num="0014"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="left">coating color</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">nat. CaC0₃ 60% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="left">50%</entry></row><row><entry namest="col1" nameend="col1" align="left">nat. CaC0₃ 70% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="left">50%</entry></row><row><entry namest="col1" nameend="col1" align="left">Plastic binder</entry><entry namest="col2" nameend="col2" align="left">0%</entry></row><row><entry namest="col1" nameend="col1" align="left">PVA solution</entry><entry namest="col2" nameend="col2" align="left">2.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">Crosslinking agent (MF resin)</entry><entry namest="col2" nameend="col2" align="left">1.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">Water retention knob</entry><entry namest="col2" nameend="col2" align="left">0.4%</entry></row></tbody></tgroup></table></tables>

The finished paper had the following characteristics of interest here. <tables id="tabl0015" num="0015"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="left">paper properties</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">FIBRO test contact angle after 2 sec</entry><entry namest="col2" nameend="col2" align="left">64/67</entry></row><row><entry namest="col1" nameend="col1" align="left">Farbwegschlagzeit after 30 sec</entry><entry namest="col2" nameend="col2" align="left">0.30 / 0.35%</entry></row><row><entry namest="col1" nameend="col1" align="left">Penetration after emco test after 1 sec</entry><entry namest="col2" nameend="col2" align="left">67/73%</entry></row><row><entry namest="col1" nameend="col1" align="left">Penetration after emco test after 3 sec</entry><entry namest="col2" nameend="col2" align="left">30/35%</entry></row></tbody></tgroup></table></tables>

This paper was inclined while processing in a printing press with satellite printing units for the construction of the ink on the counter-pressure cylinder. The print result was acceptable otherwise. On an 8-printing unit tower machine, the paper was on the other hand also process satisfactorily.

example 7

An attempt was made to regulate the unsuitability for a printing press with satellite printing works by delaying the Farbwegschlages, without affecting thereby the water penetration much was. It was used in this sense, the following coating color:<tables id="tabl0016" num="0016"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="left">coating color</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">nat. CaC0₃ 60% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="left">50%</entry></row><row><entry namest="col1" nameend="col1" align="left">nat. CaCO₃ 70% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="left">50%</entry></row><row><entry namest="col1" nameend="col1" align="left">Plastic binder</entry><entry namest="col2" nameend="col2" align="left">4.5%</entry></row><row><entry namest="col1" nameend="col1" align="left">PVA solution</entry><entry namest="col2" nameend="col2" align="left">1.5%</entry></row><row><entry namest="col1" nameend="col1" align="left">CMC solution (low viscosity)</entry><entry namest="col2" nameend="col2" align="left">1.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">Crosslinking agent (MF resin)</entry><entry namest="col2" nameend="col2" align="left">1.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">Water retention knob</entry><entry namest="col2" nameend="col2" align="left">0.3%</entry></row></tbody></tgroup></table></tables><tables id="tabl0017" num="0017"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="left">paper properties</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">FIBRO test contact angle after 2 sec</entry><entry namest="col2" nameend="col2" align="left">66/69</entry></row><row><entry namest="col1" nameend="col1" align="left">Farbwegschlagzeit after 30 sec</entry><entry namest="col2" nameend="col2" align="left">0.50 / 0.55%</entry></row><row><entry namest="col1" nameend="col1" align="left">Penetration after emco test after 1 sec</entry><entry namest="col2" nameend="col2" align="left">70/75%</entry></row><row><entry namest="col1" nameend="col1" align="left">Penetration after emco test after 3 sec</entry><entry namest="col2" nameend="col2" align="left">31/37%</entry></row></tbody></tgroup></table></tables>

The show Papierprüfdaten that the intended aim could be achieved by some reduction of the plastic binder and for a 1% addition of CMC to the coating color. When printing of this paper on a machine with satellite printing units, only a small color composition showed.

Examples 8 and 9

These experiments were the evidence of rising strength of play in the binder of the coating color on absorption time and water penetration. To compensate for the influence of the total strength partially, a sodium bentonite was in coating pigment used in addition.<tables id="tabl0018" num="0018"><table frame="all"><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="left">coating color</entry><entry namest="col2" nameend="col2" align="center">example 8</entry><entry namest="col3" nameend="col3" align="center">example 9</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">nat. CaC0₃ 70% &lt;2 microns</entry><entry namest="col2" nameend="col2" align="left">80%</entry><entry namest="col3" nameend="col3" align="left">80%</entry></row><row><entry namest="col1" nameend="col1" align="left">sodium bentonite</entry><entry namest="col2" nameend="col2" align="left">20%</entry><entry namest="col3" nameend="col3" align="left">20%</entry></row><row><entry namest="col1" nameend="col1" align="left">Dispersing agent (sodium polyacrylate)</entry><entry namest="col2" nameend="col2" align="left">1.5%</entry><entry namest="col3" nameend="col3" align="left">1.5%</entry></row><row><entry namest="col1" nameend="col1" align="left">Plastic binder</entry><entry namest="col2" nameend="col2" align="left">4.5%</entry><entry namest="col3" nameend="col3" align="left">4%</entry></row><row><entry namest="col1" nameend="col1" align="left">PVA solution</entry><entry namest="col2" nameend="col2" align="left">1.5%</entry><entry namest="col3" nameend="col3" align="left">1.5%</entry></row><row><entry namest="col1" nameend="col1" align="left">starch solution</entry><entry namest="col2" nameend="col2" align="left">2.0%</entry><entry namest="col3" nameend="col3" align="left">6.0%</entry></row><row><entry namest="col1" nameend="col1" align="left">crosslinking agent</entry><entry namest="col2" nameend="col2" align="left">1.0%</entry><entry namest="col3" nameend="col3" align="left">1.0%</entry></row></tbody></tgroup></table></tables><tables id="tabl0019" num="0019"><table frame="all"><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="left">paper properties</entry><entry namest="col2" nameend="col2" align="center">example 8</entry><entry namest="col3" nameend="col3" align="center">example 9</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">FIBRO test contact angle after 2 sec</entry><entry namest="col2" nameend="col2" align="left">67</entry><entry namest="col3" nameend="col3" align="left">70</entry></row><row><entry namest="col1" nameend="col1" align="left">Farbwegschlagzeit after 30 sec</entry><entry namest="col2" nameend="col2" align="left">0.33%</entry><entry namest="col3" nameend="col3" align="left">0.8%</entry></row><row><entry namest="col1" nameend="col1" align="left">Penetration after emco test after 1 sec</entry><entry namest="col2" nameend="col2" align="left">73%</entry><entry namest="col3" nameend="col3" align="left">78%</entry></row><row><entry namest="col1" nameend="col1" align="left">Penetration after emco test after 3 sec</entry><entry namest="col2" nameend="col2" align="left">31%</entry><entry namest="col3" nameend="col3" align="left">37%</entry></row></tbody></tgroup></table></tables>

The show Papierprüfdaten that Farbwegschlagzeit can be significantly slowed by the greater strength of the addition in the coating color. Nevertheless, the penetration after emco test was maintained at a similar rate as in the past games by the addition of sodium bentonite as a pigment.

The paper according to Example 8 had similar characteristics to the paper according to Example 6. It was less suitable for misprinting on a machine with satellite printing units. The paper according to Example 9 showed the best loading and printability.

It should again be noted that the printability of paper is influenced partly jointly by the water absorption capacity and the ink absorption, these two properties can be compensated to some extent. It is therefore not necessary that there are at a paper showing very good treatment and processing properties, both characteristics respectively in the preferred ranges.

Exhibit A

Fibro DAT 1100 is the name of a device made by Fibro System from, Box 9081, S-12609 Stockholm, Sweden, from a detailed prospectus was related. The letters DAT stand for "Dynamic Absorption Tester". The device is used to measure the wetting behavior of surfaces of a paper property, which must be so accurately measured and adjusted for downstream operations, such as painting, printing. It works on the principle of contact angle measurement and is based on a method that was developed by the Swedish paper research institute.

From the prospectus can be seen that the device includes a medical metering and a CCD camera, the drop size from 0.1 to 9.9 .mu.l is adjustable and that the characteristic of the wetting behavior change of discarded on the paper sample drop by storable video images can be documented with a cycle time of 20 milliseconds. The time course of the contact angle can be recorded, so that the wetting behavior of different paper samples can be easily compared.

In the present case, distilled water was used for wetting and determines the wetting after 2 seconds.

Appendix B

When counter-pressure test, also called Abschmierversuch or absorption test, a defined amount of ink is applied on a strip of paper, which is then rolled over at predetermined time intervals in sections with a counter sample strips. The votes on the crosscheck stripe color quantities are determined optically and allow conclusions to the Color Sampler behavior and stacking of the sample strip.

Details of the experiment are a detailed description of the multi-purpose sample printing machine of the company prüfbau, Dr.-Ing. Herbert Dürner, Aich 17-23, D-82380 Peißenberg / Munich to take from 26.9.1972, in particular in point 10.5 and 14.2.

Thereafter, for coated papers, a color range of 0.3 cm³, A distribution time of 30 sec in the inking unit and 30 sec for the printing form recommended. The contact pressure when pressed and counterpressure should each be 200 N / cm, ie 800 N at a printing form width of 4 cm. It is the Wegschlagtestfarbe Nr. 52 0068 Farbensabricken Michael Huber, Munich, used. The counterpressure should be carried out after 30, 60, 120 and 240 sec. As printing speed 0.5 m / sec are recommended. As proof printing paper standard paper with the designation APCO II / II is Scheufelen used.

In the present case the tests at double printing speed have been carried out in the rest of the specified values. We analyzed particularly the color transfers to the cross-check strips, which are reached after 30 seconds when reverse printing.