HU177543B - Process for preparing daub coat containing caoutchouc for artificial leathers - Google Patents

Abstract

1534763 Vulcanization paste BAYER AG 21 Jan 1976 [23 Jan 1975 (2)] 17035/77 Divided out of 1534762 Heading C3C A vulcanization paste comprises (i) zinc oxide, (2) sulphur, (3) a water-soluble vulcanization accelerator, (4) a water-insoluble vulcanization accelerator, (5) titanium dioxide, (6) a dispersing agent and (7) water. Examples are given in which (3) is sodium diisopropyl dithiocarbamate, (4) is zinc diethyl dithiocarbamate and (6) is a naphthalene sulphonic acid/formaldehyde condensate. The pastes are added to compositions comprising a latex of a copolymer of butadiene, acrylonitrile, and, optionally, methacrylic acid and the compounded latex is applied to synthetic fibre fleeces, gelled and vulcanized.

Description

The present invention relates to a process for the preformation of a synthetic leather base coat. wherein the fiber blend is impregnated with rubber kits in the presence of a heat-sensitive blowing agent, the mixture is coagulated. and then vulcanize. The artificial leather base layer of the present invention has a particularly favorable water vapor storage capacity. this is up to 70 80, of the natural leather water vapor storage image scgcnck.

The invention also relates to a vulcanizing paste used in the process.

The process of the present invention is carried out by: flies made from a known branch of the art are 100 parts by weight of dry matter of rubber with 10 100 parts by weight of accelerated vulcanization and accelerator. and the other components of lalex are insoluble and inert emulsifiable material, preferably containing a silicone-oil-coulomb, with a mixture of rubber and rubber, wherein 100 parts by weight of rubber solids are impregnated between 5 and 50 parts by weight. heat-coagulating in a known manner. then cured and dried in known manner

It is known from German Patent Publication No. I 570088 to be vapor-permeable. microporous. rubber-coated impregnated carrier-based flat surface products. Although these products are microporous, they have a certain water vapor permeability. however, they are not capable of storing from water vapor. The process proposed for their preparation for large-scale industrial production of large surfaces is practically unsuitable, since the Latcx mixture to be used is only stable for a short time and is therefore unsuitable for continuous impregnation. V

Therefore, there is a need to provide a synthetic leather backing. which, on the one hand, has a large capacity for storing water vapor and, on the other hand, can be easily produced in a non-product form. The design of the water vapor storage image scg * is particularly important as it is one of the most prominent properties of natural skins that has not been satisfactorily achieved in synthetic products so far

It is therefore an object of the present invention to provide a nonwoven rubber latex impregnated synthetic leather base material which has a water vapor storage capacity of 2 * wt based on the dry weight of the material. With a weight of 250 kg cm s / akitos / longitude νΓ ,, has tensile elongation

In the manufacture of a synthetic leather base layer, a fleece made of fibrous material consisting of natural fibers and / or synthetic fibers is used. use of flies made of polyester, polypropylene, viscose cellulose fibers.

For the impregnation of virtually any heat-sensitive natural or synthetic rubber latex, such as the following natural synthetic rubber latexck hutadicn acrylonitrile, butadicn sirole are suitable. chloroprene and butadiene acrylic acid mixed polymer. and isoprene and the corresponding blends with a polymer based carboxylate. and non-carboxylated Laixes Λ pob5 merizates may additionally contain acid amide and on-crosslinking groups such as N-metdolacrylamide.

According to the invention, for example, the following heat sensing agents may be used in polyvinylmethyl ether. polyethylene lene or polypropylene oxide adducts and / or mixtures thereof. polyalkyl or arylsiloxanes and ethylenediamine polyether adducts.

Suitable vulcanizing agents are, for example, dispersions of sulfur, zinc oxide and vulcanization accelerator. In the case of reactive polymerizates, which are generally cured without sulfur and without vulcanization accelerator, they are cured with melamine. condensation products of urea or phenol with formaldehyde or metal oxides are included.

However, it is preferred to use polymerizates which do not have crosslinking groups. For the crosslinking of these polymers according to the invention, the latex is preferably added in the form of a dispersion or paste suitable for vulcanization. This paste contains, in addition to water, a dispersant and known fillers, such as titanium dioxide, conventional vulcanizers, such as sulfur and zinc oxide, and, in addition to the water-insoluble, vulcanization accelerator according to the invention, a very rapid water-soluble vulcanization accelerator.

The presence of a fast acting vulcanization accelerator is very important. As such, various water-soluble sodium or ammonium salts of dithiocarbamic acid, preferably in combination with mercaptobenzene-thiazole salts, are preferably used. Suitable fast-acting water-soluble vulcanisation accelerators include, for example, dimethyl, diethyl, diisopropyl and dibutyldithiocarbamic acid, their alkali, alkaline earth metal and ammonium salts. The advantage of using a water-soluble vulcanisation accelerator over a water-insoluble accelerator is that it acts very quickly, which leads to the formation of a very favorable synthetic leather base coat.

Zinc salts of the dithiocarbamic acids listed above as water-insoluble vulcanization accelerators. mercaptobenzene diazole and its zinc salts, thiuram and derivatives thereof may be used. Suitable dispersants are, for example, naphthalene sulfonic acid and formaldehyde concentration products.

The vulcanizing paste of the present invention has the following composition:

0.5 to 10.0 parts by weight of zinc oxide, preferably about 5.0 parts by weight

0.2 to 10.0 parts by weight, preferably about 2.0 parts by weight of sulfur

0.2-3.0 parts by weight are known water-soluble accelerators, preferably about 1.0 parts by weight

2.0 to 3.0 parts by weight are known water-insoluble accelerators, preferably about 1.0 parts by weight

2.0 to 15.0 parts by weight, preferably about 5.0 parts by weight of titanium dioxide

0.1 to 5.0 parts by weight is preferably about 1.0 parts by weight dispersant

10.0 to 50.0 parts by weight is preferably about 25.0 parts by weight of water

The amount of paste to be used can vary over a wide range. Based on 100 parts by weight of dry rubber, conventionally, 10 to 100 parts by weight of vulcanizing paste, preferably 30 to 50 parts by weight, most preferably 40 parts by weight are used.

The vulcanizing paste is prepared by mixing water and a dispersant and a suitable aqueous solution of the dispersant and adding the usual components. The mixture and its ingredients are then stirred vigorously for 12-72 hours, preferably 24 hours, and ground, for example, in a ball mill. In this way, a ready-to-use vulcanizing paste is obtained which contains the ingredients in finely divided form.

According to the invention, the following insoluble and inert materials are suitable for use as a pore former:

1. long-chain aliphatic or alicyclic isocyanates,

2. N-Methylated Melamine. condensates of urea or cyclic urea with long chain fatty acids or their amides, lower alkanols and long chain amines,

3. perfluorinated long-chain aliphatic compounds

4. polyvinyl methyl ether

5. A mixture of epoxy resin and polyether siloxane

6. a mixture of polyethylene polyether siloxane

7. mixture of 1-6 products

By way of example, the following products are mentioned: stearyl isocyanate; condensate of hexamethylated melamine with an acid of formula C21H43COOH; perfluorinated stearic acid; Polyvinyl methyl ether having a molecular weight of 30,000 to 70,000; low molecular weight polyethylene with polyether siloxane.

Of the silicone oils, silicone oils having a viscosity of from 50 to 1000 cP, preferably in the form of an aqueous emulsion having a solids content of 10 to 50% and preferably containing nonionic emulsifiers, are particularly suitable for pore forming.

Generally, the rubber latex mixture will comprise 100 to 300, preferably 220 parts by weight of water, 100 parts by weight of rubber, 0.5 to 5, preferably 1 part by weight of heat sensitizing agent, 3 to 10, preferably 7 parts by weight of vulcanizing agent, 1-4, preferably 2 parts by weight. and 0.5 to 10, preferably 5 parts by weight of pore forming material.

This mixture is used to impregnate the fibrous flute in a conventional manner. 50 to 200% by weight of the fleece is taken from the mixture. The impregnated flute is then heated to a temperature of 25-80 ° C. Since the latex mixture contains a heat sensitizing agent, the latex mixture coagulates very rapidly above the specified temperature. Immediately after coagulation, the impregnated blister must be cured. It is very important for vulcanization to be carried out as quickly as possible. Therefore, vapor vulcanization is preferably employed at a temperature of 100 to 200 ° C. The vulcanization is carried out for 5 to 60 minutes. The vulcanized impregnated fluff is then dried in a conventional manner at 100-170 ° C under vacuum.

In this way, a synthetic leather base layer is obtained which has the most outstanding property of its water vapor storage capacity. This backing layer may be provided with a topcoat in a manner known per se, for example a microporous thin polyurethane layer. The artificial leather obtained in this way is very valuable and very close to the natural skin in its properties.

The invention is illustrated by the following examples:

Example 1

Stitched and ultimately shrunken fibrous fluff (composition: 60% polyamide staple fiber about 40mm, 1.5 den and 1.5% polyester staple fiber about 40 mm, about 40 mm, 1.5 denomination) impregnated with a mixture so that 100 g of the latex mixture is obtained per 100 g of fibrous material. The impregnated flute is then heated rapidly to 50 ° C, which causes the latex mixture to gel. It is then cured with steam at 105 ° C for 30 minutes and finally dried in hot air. The slab is then ruptured and the final product layer thickness is shown in Table 1. This gives a microporous synthetic leather base material with a water vapor storage capacity of 4.4% (the test method is

After Table 3). The latex mixture used has the following composition:

210.0 parts by weight 47 ° latex. consisting of 85.0% by weight of a copolymer of ¹¹ , butadiene and 5 15.0% by weight of acrylonitrile (= 100 parts by weight of dry matter),

10.0 parts by weight of a 50% silicone oil emulsion (100 to 1000 cP) dissolved in a solution of 214% in a condensation product of 1 mol of benzylphenylphenol with 20 mol of ethylene oxide,

1.0 part by weight of polyether siloxane

8.0 parts by weight of benzylphenylphenol

75.0 parts by weight of water

41.0 parts by weight of vulcanizing paste consisting of 2.0 parts by weight of colloidal sulfur, 5.0 parts by weight of zinc oxide, 1.0 parts by weight of zinc diethyldithiocarbamate, 5 parts by weight of titanium dioxide, 1 part by weight of diisopropyldithiocarbamic acid sodium and 27 parts by weight of naphthalene. is formed from a 5% aqueous solution of the condensation product of sulfonic acid with formaldehyde.

The latex mixture has a coagulation point of about 40 ° C.

1. Comparative experiment

The procedure of Example 1 was followed except that polyether siloxane and diisopropyl, carbamic acid sodium (very good accelerator) were not added to the mixture. In addition, vulcanization is carried out not in a vapor atmosphere, but in air at a temperature of 110 to 130 ° C. The material thus obtained has a water vapor storage capacity of 0.6%.

The results are summarized in Table 1. Corresponding values for split skin are also provided for comparison. 35

2-4. example

60% (approx. 40 mm, 1.5 den) polyamide staple fiber and 40% (approximately 40 mm, 1.5 den fineness) polyester 40 space staple with the latex mixture specified below impregnating so that 100 g of fibrous material is added to 100 g of solids from the latex mixture. The impregnated blister is then heated rapidly to 50 ° C, which causes the latex mixture to gel. It is then cured with steam at 105 ° C for 30 to 45 minutes and finally dried in hot air. The flea is then split; the thickness of the final product is shown in Table 2. This gives a microporous synthetic leather base material having a water vapor storage capacity of 4-5% (the test method is described after Table 3).

The latex mixture used has the following composition: 210.0 parts by weight of 47% latex, which is 60.0% by weight of butadiene and

It consists of 36,0% by weight of acrylonitrile and 4,0% by weight of a copolymer of 55 methacrylic acid (= 100% dry matter),

a) 15.0 parts by weight of stearyl isocyanate, 33% emulsion,

b) 15.0 parts by weight of a mixture of polyether siloxane and polyethylene 60% emulsion 33%,

c) 30.0 parts by weight of methylated myel in

C _2i H _4J formed COOH Calculated compound A condensation product, 16.5% emulsion 65

d) 30.0 parts by weight of approx. 50000 molecular weight polyvinyl methyl ether, 16.5% emulsion

1.0 part by weight of polyether siloxane

2.0 parts by weight of benzylphenylphenol

75.0 parts by weight water

41.0 parts by weight of vulcanizing paste consisting of 2.0 parts by weight of colloidal sulfur, 5.0 parts by weight of zinc oxide, 1.0 parts by weight of zinc diethyldithiocarbamate, 5 parts by weight of titanium dioxide, 1 part by weight of diisopropyldithiocarbamic acid sodium and 27 parts by weight of naphthalene sulphonic acid is a 5% aqueous solution of its condensation product.

The latex mixture has a coagulation point of about 40 ° C.

2, comparative experiment

Example 1 was followed. except that insoluble and inert substances in rubber and other latex constituents (including the pore forming agent) and diisopropyldithiocarbamic acid sodium (a very good accelerator) are not added. In addition, vulcanization is carried out not in a vapor atmosphere but in air at a temperature of 100-130 ° C. The material thus obtained has a water vapor storage capacity of 0.6%.

The results are summarized in Tables 2 and 3. Corresponding values for carcass skin are also given for comparison.

The results show that a comparative experiment in the known manner yields a base layer of synthetic leather with very low water vapor storage capacity. In contrast, water vapor storage capacity of the compositions of the present invention is significantly increased.

Table 3

Vízgőzfelvétel *

n. 4 o'clock SHE ' II n. 8 hours ° / n. 24 hours She Comparative experiment 0.6 0.6 0.6 Suede 5.3 6.2 6.9 2-4. Example a) Variation 1.4 2.1 3.9 2-4. Example b) Variation 1.7 2.2 4.4 2-4. Example c) Variation 1.5 2.7 4.4 2-4. Example d) Variation 1.7 2.2 4.8

* The water vapor storage capacity is determined by the following method:

The specimens are prepared at 50 x 20 mm / 24 h at 20 ° C in a 65% RH climate. It is then weighed to the nearest 0.0001 g and transferred to a climate chamber having a relative humidity of 86% at 20 ° C. After 4.8 and 24 hours of storage, weight gain was determined to the nearest 0.0001 g.

As a result, weight gain is expressed as a percentage of the weight after conditioning.

Measurement results are calculated as the average of 3 measurements.

The measurement results show that the artificial leather base layer produced by the present invention has a significantly more favorable property than the products obtained in the known manner.

1, Table

Direction Layer pull sections Weiter- fiery durable pressures thick- solid- dog elongation kind of tear bending other Stretching (2) width (mm) pany 7 / n tensile solid- solid- IUP4- kp / cm ^{1 2} (DIN solid- pany goodness (1) by (DIN 53 328) pany kp / cm IUP 20 53 328) kp / cm (DIN 1% 11% n.4 ^h n.8 ^h n.24 ^h (DIN 53 329) 7 7 7 53 329)

Comparative

experiment longitudinally 1.0 78 90 44 69 \ 3.6 25 11.5 0.6 0.6 0.6 cross 1.0 97 110 39 64 Example longitudinally 0.9 58 90 27 62 \ 25 10.3 4.4 cross 0.9 106 70 35 61 < 4.5 4.6 slit Skin longitudinally 1.5 198 50 48 140 \ 5.3 5.9 6.9 cross 1.5 203 50 52 130

(1) Bally flexometer, dry 200,000 bends (IUP 20) <meaning: damaged> means: not damaged (2) Stretch, measured by Bally tensometer (IUP 13) (3) according to the method given in Table 3

I = linear elongation = residual elongation

Table 2

lránx Thickness 1UP4 (mm) Tensile strength * kp / cm ² (DIN 53328) Tear * elongation 0 / o (DIN 53328) Weiter * tensile strength kp / cm (DIN 53329) Stitch * step strength kp / cm (DIN 53329) Bending strength (1) (IUP 20) Stretching (2) (IUP 13) Nyo · other  1% II% A comparison parative experiment longitudinal 1.0 78 90 44 69 X cross 1.0 97 110 39 64 X 3 b 25 11.5 Example 4 Longitudinal 1.1 58 90 27 62 cross 1.1 106 70 35 61 X. 3.2 25 10.3 slit skin longitudinal 1.4 198 50 48 140 cross 1.4 203 50 52 130 > - -----

(1) Measured with Bally's flexometer, dry 200,000 bends (IUP 20) <meaning: damaged> meaning: not damaged (2) Elongation, measured with Bally's strain gauge (IUP 13)

I - linear elongation = residual elongation * These values are almost identical to the values of the pore-forming material a) -d).

Claims (3)

CLAIMS 1. A method for producing a synthetic leather base layer 5 having a water vapor absorption capacity of 2 to 8% by weight and a tensile strength of 30 to 250 kg / cm ^{2, having a} tensile strength of 30 to 150% by impregnating a fibrous flute with a rubber mixture. the system is subsequently vulcanized, characterized in that the fibrous flute is comprised of 50 to 200% by weight of the rubber latex blend of 50 to 200% by weight of the known amount of the known thermal sensitiser, based on 100 parts by weight of rubber solids. , 10 to 100 parts by weight of vulcanizing paste - which 0.5 to 10 parts by weight of zinc oxide, 15 0.2 to 3 parts by weight of sulfur, 0.2 to 3 parts by weight of known fast acting water soluble vulcanization accelerators, 0.2 to 3 parts by weight of known water-insoluble vulcanization accelerators, 20 2 to 15 parts by weight of titanium dioxide, 0.1 to 50 parts by weight of water, It consists of 0.1 to 5 parts by weight of a dispersant and 0.5 to 10 parts by weight of a pore former insoluble in rubber and other latex components, preferably polyether siloxane, and other known additives, and then coagulates the latex mixture at a temperature of 25-80 ° C. It is vulcanized for 5 to 60 minutes at 100 to 200 ° C and then dried at 100 to 170 ° C in vacuo. 2. A process according to claim 1 wherein the water-soluble vulcanization accelerator is selected from the group consisting of an alkali metal, an alkaline earth metal or an ammonium salt of dimethyl, diethyl, diisopropyl or dibutyldithiocarbamic acid or a mixture thereof. 3. A process according to claim 1, wherein the water-insoluble vulcanization accelerator is dithiocarbamic acid zinc salt. mercaptobenzotriazole or its zinc salt or thiuram and derivatives thereof.