Moulded articles

(74) Agent: Simonnot, Rinuy, Santarelli.

Process for producing an object in microporous elast omer material permeable to water vapour.

Invention of:

33) (32) (31

Convention priority: Patent application filed in the United States of America on December 1969, n. S84.571 in the name of Stanley Irving Hayes, Jr.

Sale of booklets to IIMPRIMERIE NATIONALE, 27, street of Convention - PARIS (15^e)

44854

-1207368Î

The present invention relates to the production of articles of clothing, such as shoes and gloves, and more particularly to the molding of a shoe upper or a preformed glove in one piece.

The manufacture of shoes and gloves has traditionally involved the attachment of a number of pieces of flat material such as leather or fabric. The shoes are then shaped by stretching the assembly over a last to give it a curved three-dimensional configuration. The process is long and costly and imposes conditions on the materials of the shoe upper which have no direct relationship to the behavior of the materials in the fi nished shoe. The tension imposed on the materials is acceptable for leather, since it is made up of fibers arranged in a three-dimensional arrangement which remains strongly engaged with each other during and after the traction. On the other hand, leather replacement products usually include a decorative outer layer_fwear-resistant, of an elastic polymeric material and one or more inner or backing layers of woven or non-woven fabric. When they are stretched, for example during assembly, the fibers of the fabric are rearranged in accordance with the new contour, but the outer layer is simply thinned, so that the appearance of its surface is altered. In many cases, the outer layer can no longer hide the texture of the fabric backing with which it is associated. Since the outer layer is elastic, there are internal tensions which promote cracking and the development of a notch.

In US Patent No. 2,904,838 it has been proposed to mold a preformed shoe upper of thermoplastic material. Molded rubber or plastic gloves are also known. However, a shoe or glove molded in this way is not permeable to air or water vapour. Also, thermoplastic materials are generally not sufficiently resistant to heat and to the attack of chemicals and solvents which may come into contact with a shoe or glove during their use.

the present invention relates in particular to:

-20073681

- To form a shoe upper or a glove of porous elastomeric material in one piece without it being necessary to assemble a certain number of parts and without it being necessary to stretch the material around a shape;

- to produce a shoe upper or a glove in microporous material which resists heat and the attack of chemicals and solvents.

For these purposes, and according to a characteristic of the present invention, a layer of solidifiable liquid material in the form of an elastomeric microporous body is formed against a molding surface complementary to the contour of the shoe upper or of the glove to be produced and is transformed in the solid microporous state, which gives it properties allowing it to be used as a shoe upper or a glove;

- a shoe upper or microporous glove made of at least partially cross-linked elastomeric material giving it resistance to heat and to damage by chemicals and solvents.

Other advantages and characteristics of the invention will become apparent from the description which follows, made with reference to the appended drawings and giving by way of explanation, but in no way limiting, an embodiment of the invention.

In these drawings:

Figure 1 is a perspective view, with parts broken away, showing a mold on the walls of which is a shoe upper partially formed with an additional solidifiable liquid material to complete the shoe upper;

Figure 2 is a perspective view of a shoe upper formed in the mold after cutting the ankle and bottom openings;

Figure 3 is a perspective view of a finished shoe including the molded shoe upper;

Figure 4 is a perspective elevation of the front portion of another form of shoe mold for making a shoe upper, the mold being partially cut away to show a shoe upper formed in the mold and to indicate the disposal of a . reinforcement intended to be combined with the shoe to form an integral part thereof during molding; and

-5073681 Figure 5 is a perspective view of a finished shoe including the molded upper of Figure 4, with a portion cut away to show the location of the reinforcement in the shoe.

the method of the present invention will be described with reference to the manufacture of shoes, but it is understood that the methods described can also be applied to the manufacture of other microporous molded articles such as gloves.

Shoes or shoe uppers and gloves are made according to the present invention by casting or molding a reactive liquid composition to form a unitary flexible and tenacious microporous body with the contour and surface conformation of a shoe, upper shoe or glove, the composition of the liquid and the casting or molding conditions are chosen so as to maintain fluidity during the introduction of the liquid material into the mold to allow it to conform to the smallest details and then to harden in the state retaining the shape in a short enough time to allow it to be removed from the mould.

the liquid composition intended to be molded into a shoe, shoe upper or glove is an emulsion containing controlled size droplets of a liquid dispersed in a continuous phase of a preferably reactive material polymer that can be transformed by reaction into a solid, flexible and tough material, the dispersed liquid is chosen so that its dissolving or swelling action on the polymer material is zero or very limited, when the continuous phase solidifies, the droplets are maintained in the dispersed state and are then eliminated, for example by evaporation, to leave pores or microporous passages.

the preferred reactive materials are those capable of forming reaction products of the polyurethane or polyurea type which are tough, flexible and of high mechanical strength, the reactive material can be a direct mixture of an organic compound having at least two active hydrogen atoms , such as a polymer polyol, for example a polyalkylene-ether-polyol and/or a polyester-polyol, with a reactive compound having at least two reactive '-K00 groups, for example a polyisocyanate or else

44854 This may be a prepolymer system in which a KCO-terminated reaction product of a polyol and excess polyisocyanate is combined with chain extenders which may be compounds polyhydroxylated and/or polyamines.

The reactive material must be either liquid or transformable into liquid.

Polyols which are useful in the direct blend or to form the reactive prepolymer include substantially linear or only moderately branched polyether polyols and substantially linear or moderately branched polyester polyols obtained by polymerization of lactones or by condensation of polyacids. for example adipic, sehacic, azelaic, dimerized linoleic acids, as well as other aliphatic and aromatic diacids with polyols such as hutane15 diol, ethylene glycol, propylene glycol, etc. Castor oil is also a suitable polyol for preparing a prepolymer. Polyols or polyacids having more than two reactive OH or -OOOH groups can be incorporated into the reactant compositions to form polyester-polyols to introduce moderate branching or crosslinking and thereby achieve greater heat resistance and to solvents. As little as 0.5% by weight of these polyols or polyacids having more than two reactive OH or -OOOH groups provides a marked improvement in these properties and an amount of up to 20% can be used.

The prepolymers are prepared by well-known procedures of reacting polyether polyols or polyester polyols with organic polyisocyanates including toluene diisocyanates, methylene diisocyanates, and the like.

A proportion of polyisocyanate having more than two isocyanate reactive groups can be incorporated to achieve the desired degree of crosslinking. When the polyol is difunctional, as little as 0.5% polyisocyanate having more than two NCO groups provides a marked improvement in heat and solvent resistance and up to 20% can be used. . when the polyol contains components having

- more than two active hydrogen atoms, the effects of cross-linking • seem to add up and the sum of the percentage of isocyanate

44854 -s- 2073681 having more than two -NCO groups and the percentage of compounds having more than two active hydrogen atoms, should normally not exceed about 20%.

The action of the non-dissolving pore-forming liquid is mainly physical, i.e. the liquid having no dissolving action is a space-filling filler which can be easily removed and which is present in the form of dispersed droplets until the coating solidifies at least partially around said droplets and which is subsequently removed to leave empty spaces and pores. Liquid removal is carried out without expansion of the solidified mass. Suitable liquids can be readily selected by a chemist based on the known physical properties of the liquids. Any liquid which has substantially no solubilizing effect on the polymeric material and which does not react with the latter, and which has suitable volatility characteristics, can be used. Normally liquid aliphatic hydrocarbons including petroleum moieties, particularly those commercially available, such as mineral spirits, petroleum naphtha and kerosene, which are substantially or entirely aliphatic in nature, are generally preferred because of their low price and their satisfactory behavior in the composition; but it is possible to use other substantially inert organic liquids such as liquid alkyl ethers, for example amyl ether or butyl ether, and liquid halogenated hydrocarbons, preferably halogenated aliphatic hydrocarbons such as as chlorodecane, tetrachloroethylene and tetrachlorodifluroethane. To avoid premature evaporation so that it can play its role of filling the spaces until solidification of the continuous phase, a pore-forming liquid is chosen having a boiling point higher than the reaction temperature chosen and it must advantageously have a boiling point of at least about 100° C. and preferably at least 130° C. in order to be able to use temperatures which provide the desired rate of reaction of the polymeric material. On the other hand, one chooses a liquid having a sufficiently low boiling point so that it can be eliminated without the heat having a detrimental effect on the solidified material.

44854 -62075681

Thus, the liquid usually should not contain significant amounts of high-boiling or low-volatility components and it is preferred that at least 90% of the liquid's components boil at a temperature below 232⁰^. It is understood that means other than evaporation, for example extraction, can be used to remove the high boiling point or low volatility liquid, - .c in this case, the upper limit of the point of boiling does not apply.

The dispersion of the droplets of the pore-forming liquid in the heated liquid mass of the reactive polymeric material, to form an emulsion in which the said polymeric material constitutes the continuous phase, is carried out by vigorous agitation during the addition of the pore-forming liquid to the mass of the material. polymer. Emulsifying agents are useful to promote dispersion of the liquid in the polymeric material and to stabilize the resulting emulsion.

A chemist versed in the art of forming emulsions can easily select suitable emulsifiers. Preferred emulsifiers contain anionic and nonionic surfactants such as commercially available silicone emulsifiers, partial esters of long chain fatty acids and polyoxyalkylene type derivatives of these esters, as well as sulfuric esters, alcohols long chain fatty, etc.

The dispersed amount of the pore-forming liquid varies depending on the desired porosity of the final product and can range from 25 parts liquid per 100 parts polymer to 300 parts liquid per 100 parts polymer material. It is desirable that the mechanical conditions of dispersion of the liquid and of the polymer be adjusted to form very small droplets, the greater part of which have a diameter comprised between approximately 0.001° and 0.03 mm.

The res.-tion of the polymeric material to make it a solid material with higher molecular poz / s is driven and determined by the conditions of time and temperature of the contacting of the reactive components and / or by the introduction of a catalyst. In the one-phase or direct process, in which a polymeric polyol such as a polyether-polyol or polyester-polyol, is reacted

448^4

-7with a polyisocyanate, the mixing and emulsification involves bringing these materials into contact with the liquid to be dispersed and a catalyst, such as stannous octoate or lead naphthenate, so as to control the rate of the reaction . It is understood that, when the reaction is so rapid that it is difficult to complete the emulsion before a significant increase in viscosity occurs or solidification of the polymeric material, the pore-forming liquid can be emulsified in the one of the reactants, usually the polyether- or polyester-polyol, before combining it with the polyisocyanate.

In the two-phase process, an HOO-terminated prepolymer, prepared from a polyol-polymer, such as a hydroxylated polyether or polyester, and from a polyisocyanate, the blowing liquid and the extenders Reacting with the prepolymer to give higher molecular weight materials are combined and emulsified with the prepolymer forming the continuous phase. Chain extenders, which have the effect of increasing the molecular weight of the prepolymer, are compounds with two or more active hydrogen atoms, such as ρ,ρ'-methylene-dianiline, 4,'4 '-methylene-bis(2-chloro-aniline), trimethylolpropane, m-phenylenediamine, 1,4-butane-diol and triethanolamine.

The reactive liquid emulsion can be cast in the form of a shoe upper by various processes including the processes resembling rotational molding, press molding and injection molding, molding or casting the reactive liquid emulsion of low viscosity does not require high temperatures or pressures and the molds can be made of any of a wide variety of materials including metals, rigid plastic materials such as reinforced epoxy resin, elastomers such as silicone rubber, polyurethane type elastomers, etc.; With many of these substances, it is desirable to use a release surface, such as silicones or fluorocarbons. It has also been found that a desirable characteristic of the surface, for example a color or a very shiny state, can be obtained by depositing a finishing material, for example by spraying, on the internal face of the mold before introducing the reactive emulsion. After solidification and curing of the reactive material, the final layer is

44854

-82073681 entirely part of the main mass of matter. This final layer can be formed by a pigmented solution, a dispersion or a resin latex with which the reactive material chemically combines or adheres strongly, the preferred materials are those which give a surface permeable to water vapour, preferably microporous , for example a dispersion of a pigment in a reactive emulsion analogous to that of the mass of molding material or solutions or latexes of hydrophilic resins or plastics such as copolymers of acrylic acid with a lower alkyl acrylate, or cellulose derivatives.

In the rotational molding process, a metal mold 10 is used, the interior of which has a shape complementary to the desired contour and the outer surface of a shoe upper (FIG. 1). the area of ​​the normal ankle opening is closed by a wall 12 covering portions 14 of the mold corresponding to the upper edge of the shoe upper, and a removable closure element 16 is used for an opening 18 formed in the mold in the part corresponding to the underside of the shoe. As shown in Fig. 1, lugs 20 formed along the edges of the closure member 16 are in coincident positions with the lugs 22 of the mold 10, when the closure member and the mold are assembled, and devices retainers, such as spring clips 24, are used to hold closure member 16 in sealing contact with the mold.

When the closure member 16 is removed and the mold 10 is placed so that the opening 18 corresponding to the bottom is in the raised position, a measured quantity of the liquid reactive emulsion is introduced into the mold, the closure member 16 in place and staples 24 are applied to hold the member in place. Then, the mold is slowly rotated around its longitudinal and transverse axes so that the liquid emulsion flows by gravity over the entire surface of the mold. This rotation can be carried out in a chamber whose temperature is regulated. The reaction of the reactive components of the emulsion increases the viscosity of the emulsion and forms a gelled layer 26 uniformly covering the internal walls of the mold 10. When the emulsion has gelled, the rotation can be interrupted and leave _9'7

3681 the reaction will continue to increase the strength of the layer enough to handle it. Final curing of the gel coat as a cast shoe upper 30 may be performed before or after its removal from the mold 10. The closure member 16 is removed and the cast upper 40 is pulled out of the mold 10. The material located in the parts corresponding to the opening 32 reserved for the ankle and to the opening 34 corresponding to the underside of the shoe of the shoe upper 30 is cut out, then the liquid of the dispersed droplets is eliminated, for example by evaporation to leaving microscopic holes or passages in the cast shoe upper.

As shown in Figure 2, the cutting of the material of the underside of the shoe leaves a marginal portion 25 intended to be fixed to a sole. The shoe is completed by attaching a sole 36 to the mounting margin 28, such as by a conventional bonding process or by molding or casting a sole directly to the shoe upper 30.

In another molding process, a liquid reactive emulsion is injected through a passage 38 into a split mold 40 which may have an internal surface comparable to that of the mold used in the first process, but which is in two parts 42 and 44 which are united to form a closed chamber_?as seen in Figure 4, which can be separated to remove a molded shoe. A core 46 having an outer surface corresponding to the injured inner surface of the shoe is mounted in the split mold 40, the surface of the core 46 being spaced from the inner surfaces of the mold 40 to leave a cavity having the desired thickness. In a preferred embodiment, the core 46 is sized and shaped such that the distance between its surface and the molding surface of the split mold 40 is greater in areas selected to impart greater thickness to the corresponding areas of the mold. the shoe upper in order to obtain greater mechanical resistance and/or rigidity. The core 46 is held in the desired position relative to the mold 40 by a centering pin 48. Der vents 50 connect the surface of the core to an orifice 52 to allow the escape of the air displaced when the liquid to be molded is introduced into the mold 40. One can

44854

-102073681 provide a means (not shown) to shorten the core 46 and facilitate the removal of the molded shoe. Also, heaters such as electric heaters (not shown) can be used in the core to promote evaporation of non-dissolving liquid from a shoe upper after mold parts 42 and 44 are separated.

Reinforcing elements 54 can be molded into a shoe upper 58 to reinforce points subjected to localized forces, such as the junction 60 between the tongue 62 and the upper 64 of the shoe. These reinforcement elements can be, for example, of tough woven or non-woven fabric and can be mounted on the core 46 as seen in Figure 4. Any suitable mounting member such as shrink rods (not shown) or low strength adhesive can be used to hold the reinforcing members in place during mold filling. The overall reinforcement can be achieved by placing on the core an element in the form of a slipper, which can be extensible, for example in knitted fabric. In this case, the engagement of the slipper-shaped element on the core can make the presence of an auxiliary mounting element unnecessary.

The solidifiable liquid to be molded in the form of a shoe is introduced into the molding space through the passage 38 passing through the wall of the split mold 40. Thanks to the low viscosity of the solidifiable liquid, a very low pressure is sufficient to fill the mold. For example, a gauge pressure of 0.14 bar has proven satisfactory.

After filling, the mold 40 is kept closed until the liquid has solidified. Parts 42 and 44 of mold 40 are then separated from the molded shoe upper, the core

46 is shortened if a shortening device is provided, and the molded shoe upper 58 is removed from the core 46. The liquid dissolving the dispersed droplets can be evaporated from the solidified material after separating the parts 42 and 44 from the molded upper either before or after removing the upper from the core 46, and the shoe is completed as in the first process described. , the reinforcement elements 54 are firmly connected to the molded microporous parts of the shoe, so

-112Q73681

44854 to be able to withstand the forces imposed during use of the shoe.

press molding is a process (not shown) in which liquid molding material is poured into a mold cavity and the mold core is pressed into the cavity to move the liquid up and down in the space between the core and the casting surface. In this case, the liquid emulsion is solidified, the surface of the molding is removed from the solidified material, the non-dissolving liquid of the dispersed droplets is removed and the shoe is completed as in the process involving injection of the reactive emulsion into a mussel. This process can be carried out because of the very low viscosity of the molding material and is particularly advantageous because it requires very little equipment for molding shoe-like shapes.

the following examples are given by way of illustration, but not limitation, of the invention.

Example 1

150 g of an NCO-terminated prepolymer prepared by reacting p,p'-diphenylmethane diisocyanate and hydroxylated polyhutylene adipate at a molar ratio of 2:1 are liquefied and degassed at 100° C., the prepolymer resultant having a molecular weight of 1540 and being solid at room temperature, and mixed with 4.5 g of a polyoxyalkylene ether having a hydroxyl value of 20, which is solid at 25°C, and gold brings The mixture at a temperature of 70⁰VS_oh 172 cm 3 of a mixture of liquid paraffinic hydrocarbons (boiling range 174 to 207° C.) are emulsified in the resulting hot mixture. Then, 9.23 g of 1,4-butanediol are added with stirring. 300 cm of the mixture are introduced into a metal mold having a configuration comparable to that shown in Figure 1, which has been brought to 70° C., the closure element is placed on the mold opening and the retaining clips put in place to hold the closure element. The mold is slowly rotated around its longitudinal and transverse axes to allow the liquid emulsion to flow over the entire surface of the mold. This rotation is continued for approximately 40 minutes and the mold is then maintained at 80°C for eighteen

-122073681 '4L hours. The mold is cooled, the closure element is removed and the cast upper is removed from the mold. The openings corresponding to the ankle and to the sole are cut, leaving a suitable assembly margin for bonding a sole to the upper. Gold: puts the upper on a last and we glue a synthetic rubber sole on the fitting margin by a classic process.

Example 2

An emulsion is prepared following the process described in Example 1 and the liquid is introduced into the molding space of a mold as shown in Figure 4 using a gauge pressure of 0.14 bar and preheating the mold at 70°C. After filling, the mold is maintained for seven hours at 80° C. and allowed to cool to room temperature for the next sixteen hours. At the end of this time, the separable parts of the mold are moved to allow the shoe upper to be removed from the core of the mold. The rod was held for eighteen hours at 90°C to evaporate dispersed liquid paraffinic hydrocarbons and finally matured at 105°C. A synthetic rubber sole is glued to the marginal parts of the underside of the upper and the shoe is dyed black and finished.

A molded sample of the reactive emulsion which had been processed, cured and dried under the same conditions used to mold the shoe upper was tested for permeability and found to exhibit vapor permeability of 1.4g / 30cm / 24 hour / 1.4mm water bottle.

Example 3

150 g of an -NCO-terminated prepolymer prepared as in Example 1 are liquefied and degassed at 100° C. and mixed with 4.5 g of a polyoxyalkylene ether having a hydroxyl value of which is solid at 25°C, and the mixture is brought to 70°0. 172 cm 3 of a mixture of liquid paraffinic hydrocarbons (boiling range 174°-207° 0) are emulsified into the resulting hot mixture. Then, 1 g of trimethylolpropane and 8.23 ​​g of 1,4-butanediol are added with stirring. 300 cm of mixture is introduced into a mold following the process of Example 2, it is solidified, the liquid hydrocarbons are evaporated and the object is aged.

\.s

46854

-132073681 molded as in Example 2. Next, a synthetic rubber sole is glued to the marginal portions of the underside of the upper and the shoe is colored and finished. A sample molded with the reactive emulsion which had been treated, cured and dried under the same conditions was tested for resistance to marking under pressure conditions comparable to those exerted by the butt rest in a welding press. soles and the results were compared with those of a molded sample of the reaction emulsion of Examples 1 and 2. It was found that the sample containing the tri-functional material, trimethylolpropane, has a resistance to marking approximately 10 times greater than that of the composition prepared according to Examples 1 and 2.

In another test, the material of this example was found to be insoluble in dimethyl formamide, while the material of Examples 1 and 2, which did not contain the trifunctional material, was substantially soluble in dimethyl formamide.

Naturally, the invention is not limited to the embodiment described and represented and is capable of receiving various variants falling within the scope and spirit of the invention.

4^854

-142073681