US2138909A - Process for the manufacture of waterproof shaped products - Google Patents

Description

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Patented Dec. 6, 1938 UNITED STATES PROCESS FOR THE MANUFACTURE OF WATERPROOF SHAPED PRODUCTS Egon Eliid, Karlsruhe, and Ernst Demme, Weinheim, Germany, assignors to firm Carl Freudenberg G. m. b. H., Weinheim, Germany, a society of Germany No Drawing. Application May 4, 1935, Serial No. 19,903. In Germany May 7, 1934 4 Claims.

This invention relates to the manufacture of waterproof shaped products consisting of animal fibrous material.

For the purpose of producing the shaped products one prior art procedure consists in converting animal skin or hide, hide parts, splits, leather scraps and the like by treatment with swelling agents and a mechanical teasing out or shredding treatment into products, which contain the fibres or fibre bundles in a liberated condition and converting the fibrous masses in their swollen state by procedures, such as extruding through nozzles, treating with pressure rollers or the like, into the desired shaped products, which may thereafter be solidified by drying or hardening, for example with the aid of tanning materials, fumigating liquids or fumigating gases. For swelling the skin or hide, use may be made of alkaline agents, for example milk of lime, or acid agents, for example, dilute hydrochloric acid, formic acid, acetic acid, sulphurous acid, or agents of both kinds successively. The resolving or teasing out treatment may be carried out in one or more stages. The fibrous material may be converted by mixing and kneading processes into homogeneous, for example pasty, swollen masses, whichmay then be further worked up, as described above, to the desired shaped products.

There may be incorporated with the fibrous masses, either during the course of their production or subsequent thereto, suitable additional materials, such as albumen-containing binders,

e. g., glue or size or gelatine, softening agents,

elasticizing agents, or agents having a weak tanning action, also different kinds of vegetable or animal fibres, e. g., cotton.

Shaped products consisting of fibrous hide material, such as may be obtained as hereinbefore described, are admirably adapted for many purposes of application. They possess the disadvantage, however, that they are not waterproof and that in a dry or air-moist condition they in-. ter alia assume a more or less non-elastic and occasionally crumpled condition.

Attempts by us to overcome these disadvanta'ges of prior art products by incorporating water-insoluble softening agents with the fibrous mass before converting the same into shaped products have not yielded satisfactory results. De-swelling of the fibrous mass took place, which counteracted uniform distribution of the waterinsoluble softening agents in the fibrous mass and unitform deposition of the same on the fibres.

The mechanical properties of the resulting.

shaped products were also impaired.

According to the present invention the aforesaid difiiculties are overcome and waterproof shaped products of excellent properties are ob tained, if water-insoluble softening agents, such as castor oil, paraffin oil, train oil etc. ormix- 5 tures of such substances are incorporated with the already formed shaped products before or after hardening.

This is effected by first converting the shaped products by treatment with swellingagents, if 10 necessary in the warm, into-a condition, in which they are adapted to take up the softening agents, and then introducing the softening agents into the shaped products preferably after more or less extensive removal of the swelling agent. The not yet hardened shaped products may, for example, be brought into a swollen condition by treatment with glycerine or glycerine-containing, non-aqueous liquids, for example mixtures of glycerine and organic solvents, such as methyl alcohol, and, after more or less extensive removal of the swelling agent-or swelling agent mixture has been effected, the softening agents be introduced into the shaped products by procedures, such as rubbing, pressing or squeezing in and the like. The swelling'of the shaped products may be promoted by carrying out the treatment of the same with glycerine and the like. substances in the warm. The shaped products are ,with advantage subjected to heating to moderate temperatures after the treatment with swelling agents.

An alternative procedure is, for example, first to cause the shaped products to swell by laying in water or aqueous liquids, then to effect removal, preferably extensive removal, of the water, and thereby to convert the products into a nonloosened, non-agglutinated condition accessible to the softening agents. The removal of the water may, for example, be effected by removing the main quantity of the water by procedures, such as expressing between felts or the like, care being taken to avoid complete de-swelling, and thereafter dehydrating the shaped products to the desired degree by treatment with water-displacing liquids, such as acetone, alcohol or mixtures of the same, which may, if desired, also contain other substances. The treatment of the shaped products with water-displacing liquids may, for example, comprise rinsing for some time, if desired in several stages, whereby the liquids miscible with water may, if desired, be caused to react with the shaped products in different degrees of concentration. The products'so treated may, if desired, also be subjected to a further 55 treatment, for example by laying in glycerine or a mixture of glycerine and methyl alcohol. This treatment may be followed by heating to moderate temperatures for example to about 45 C. The condition of swelling is to a certain extent fixed by this treatment. The softening agent or the mixture of softening agents may then be introduced, if desired after more or less extensive removal of the glycerine, for example by treating the products with methyl alcohol.

The loosening of already hardened shaped products is with advantage carried out by immersing the same, preferably with warming, in substantially non-aqueous, organic liquids having a swelling action. Glycerine containing a small quantity of water may, for example, be employed as swelling agent, if desired in admixture with alcohol. After complete softening of the layers, which may in certain circumstances take several hours, the swelling agent, for example glycerine, may be removed to the desired extent by suitable treatment, for example rinsing with alcohol, after which the incorporation of the softening agent is effected.

For many purposes of application it has proved to be advisable to subject unhardened'or untanned shaped fibrous hide products to a hardening or tanning treatment. According to the invention the treatment with hardening or tanning agents may take place during the treatment of the same, if desired in co-operation with one or other method of treatment or subsequent theretanning agents.

to, for example after incorporating the softening agents. In order to effect hardening or tanning the usual methods may be employed, for example treatment with formaldehyde or with the usual The process is in this case with advantage effected in non-aqueous media ormedia containing only a small quantity of water. Glycerine, containing alum in solution, or alcohol, containing chromium chloride in solution, may for example be employed for treating the shaped products. By using train oil, train oil tanning may be effected.

In the treatment of the shaped products, substances, which are adapted to influence the properties thereof, such as cellulose derivatives, cellulose lacquers and the like, may also be incorporated with the products, together with the agents as aforesaid. Such substances may, for example, be added to the water-insolublesoftening agents and the combined mixture be introduced into the shaped products.

The shaped products of this invention are resistant to water and permanently maintain their softness and elasticity. Even when subjected to the action of water and subsequent drying the shaped products remain soft and elastic.

Shaped products in the form of sheets or layers produced according to this invention may be joined together or with shaped products of other kinds, for example by cementing, the contact surfaces being, if necessary, previously roughened. The shaped products consisting of one or more layers, may be provided on one side or both sides with protective coatings, for example coatings of waterproof lacquers. The products may be embedded between widths of fabric, leather, artificial leather or the like or widths of fabric, leather, artificial leather or the like may be cemented between the individual fibrous hide sheets or layers. An alternative procedure is to apply on one side or both sides swollen, for example pasty, fibrous hide masses on to bases, for example layers of fabric, gummed or sized widths of fabric, layers of leather or artificial leather or other carriers, for example by pressing on, rolling on or the like and to introduce softening agents in accordance with the invention into the unhardened or hardened fibroushide sheets or layers.

Shaped products combined as aforesaid may also be further combined with other shaped products, for example by cementing with suitable adhesives, to form multi-layered shaped products and may be protected by coatings of lacquer or the like.

In many cases it has proved to be advantageous to work up shaped fibrous hide products, which contain certain quantities of decomposition products, such as glue or size, gelatine etc. These may be formed during the production of the fibrous masses from the skin or hide, for example by thermal treatment or may be added thereto.

The shaped products of thisinvention may be employed inter alia as membranes for gas meters or the like, as flexible tubes, for the production of waterproof clothing and outfit articles, for example raincoats, as waterproof, elastic packing materials, for ex mple for provisions, condiments and the like.

- Examples 1. -A sheet of unhardened fibrous hide material about 600 sq. cms. in size is laid for 5 minutes in 500 cos. of water, then pressed between felts and thereafter freed from water by rinsing with about 500 005. of high percent acetone or alcohol. The

sheet is then laid in 200 cos. of glycerine, in which 10 gms. of alum are dissolved, after two hours freed, for example by wiping, from the glycerine solution adhering to the surface and then heated for 2 hours to C. in a drying cupboard. By treating the sheet with liquids adapted to dissolve glycerine, for example by rinsing with alcohol, the glycerine can be more or less exten-' sively removed. The softening agents are then incorporated, for example by rubbing or pressing in.

The sheet may thereafter be protected on the surface, for example by coating the same with a cellulose lacquer.

2- A sheet ofhardened fibrous hide material about 600 sq. cms. in size is laid for one hour in a mixture of 180 cos. of anhydrous glycerine and 20 cos. of anhydrous methyl alcohol. Afterremoving the glycerine-alcohol mixture from the surface of the sheet, the latter is heated for two hours to 45 C. in a drying cupboard. After cool- I ing, the glycerine is removed with 500 cos. of 96% methyl alcohol and 2 gms. or more of castor oil are rubbed into the sheet so treated. The alcohol is evaporated by heating to 40 to C. The surface of the sheet may be protected by a thin lacquer coating.

What we claim is:

1. In a process of producing waterproof, permanently soft and elastic, shaped products, the steps comprising swelling substantially untanned fibrous animal substances by treatment with swelling agents, defibrating the swollen material, molding the resulting swollen defibered mass, then treating the molded article with solutions comprising non-aqueous glycerine whereby the article is converted into a loosened condition receptive to the absorption of softeners, substantially removing the glycerine containing solution from the article by extraction with organic solvents, and introducing water insoluble softening oils into the loosened article.

2. In a process of producing waterproof, permanently soft and elastic, shaped products, the steps comprising swelling substantially untanned fibrous animal substances by treatment with swelling agents, deflbrating the swollen material, molding the resulting swollen deflbered mass, then treating the molded article withsolutions comprising non-aqueous glycerinewhereby thearticle is converted into a loosened condition receptive to the absorption of softeners, substantially removing the glycerine containing solution from comprising non-aqueous glycerine whereby the article is converted into a loosened condition receptive to the absorption of softeners, substantially removing the glycerine containing solution from the article by extraction with organic, solvents, introducing water-insoluble softening oils into the loosened article, and forming a waterproof protective coating on the article.

4. In a process of producing waterproof, permanently soft and elastic, shaped products, the steps comprising swelling substantially untanned fibrous animal substances by treatment with swelling agents, deflbrating the swollen material, molding the resulting swollen deflbered mass, treating the same with tanning agents, whereby the molded article is hardened, then treating the molded andhardened article with solutions comprising non-aqueous glycerine whereby the article is converted into a loosened condition receptive to the absorption of softeners,substantially removing the glycerine containing solution from the article by extraction with organic solvents, and introducting water-insoluble softening go oils into the loosened article.

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