DE2601781B2 - Vulcanization paste and its use in the manufacture of synthetic leather base material - Google Patents

Description

10.0-50.0 wt.
0.1-5.0 wt.
2.0-15.0 wt.
0.5-10.0 wt.
0.2-10.0 wt.
0.2-3.0 wt.

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0.2-3.0 parts by weight

water

a disperser
Titanium dioxide
zinc oxide
sulfur

a water-insoluble one
Vulcanization accelerator and

a water soluble
Vulcanization accelerator.

3. Use of the vulcanization paste according to claim 1 and 2 for crosslinking polymer latices in the manufacture of synthetic leather base material.

The invention relates to a vulcanization paste and its use in the production of synthetic leather base material based on fiber fleeces impregnated with rubber latex. The synthetic leather base material according to the invention has a particularly high water vapor storage capacity, which is about 'JO to 80% of the storage capacity of natural. Leather achieved.

From DE-AS 15 70 088 are water vapor permeable, microporous fabrics based on with Rubber latices impregnated carrier materials are known. These products have microporosity and thus a certain permeability for water vapor, but not a storage capacity for water vapor. The manufacturing process specified for them is for the production of large areas and for industrial purposes Production practically unsuitable because the specified latex mixtures only last for a short period of time stable and therefore not suitable for continuous impregnation processes.

There is therefore a need to provide synthetic leather base material which, on the one hand, is a has a high storage capacity for water vapor and, on the other hand, is easily and reproducibly produced can be. The water vapor storage capacity is particularly important because it is one of the most excellent Properties of natural leather and in synthetic products are not yet sufficient Degree could be achieved. Such a synthetic leather base material is made with the inventive Vulcanization paste achieved.

The invention thus relates to a vulcanization paste made from (A) known fillers, (B) sulfur, (C) Zinc oxide and (D) vulcanization accelerator as well as (E) water and (F) a dispersant, characterized that the component (D) consists of a water-insoluble vulcanization accelerator and a very fast-acting, water-soluble vulcanization accelerator

This paste is based on a non-woven fabric impregnated with a rubber latex Synthetic leather base material creates this through a water vapor storage capacity of 2–8% by weight, based on the dry weight of the material, a

ίο a tensile strength of 30-250 kg / cm ² and an elongation at break of 30-150%

In the manufacture of this synthetic leather base material by impregnating a fiber fleece with a Rubber mixture, coagulation of the mixture and subsequent vulcanization is done in such a way that one a non-woven fabric with a heat-sensitizing agent, a fast-acting vulcanization accelerator and, as a pore-forming agent, a silicone oil emulsion or an inert and emulsifiable substance which is insoluble in the rubber and in the other components of the latex containing rubber latex mixture and preferred after heat coagulation of the latex mixture vulcanized in steam and then dried. The presence of a fast-acting vulcanization accelerator in the vulcanization paste is of particular importance mainly water-soluble sodium or ammonium salts of various derivatives of dithiocarbamic acid, possibly in combination with salts of the mercaptobes

JO zothiazols.

As a very fast-acting, water-soluble vulcanization accelerator the alkali, alkaline earth and ammonium salts of dimethyl, Diethyl, diisopropyl, and dibutyldithiocarbamic acids.

Water-insoluble vulcanization accelerators are, for example, the zinc salts of the above Dithiocarbamic acids, mercapto-benzothiazole and its zinc salts, thiuram and its derivatives. As a dispersant z. B. the condensation product of naphthalenesulfonic acid and formaldehyde is suitable.

The vulcanization paste according to the invention preferably has the following composition:

0.5-10 parts by weight
0.2-10.0 parts by weight
0.2-3.0 parts by weight

0.2-3.0 parts by weight

2.0-15.0 parts by weight

0.1-5.0 parts by weight

10.0-50.0 parts by weight

Zinc oxide, preferably about 5.0 parts by weight, preferably about 2.0 parts by weight, of sulfur water-soluble accelerator, preferably about 1 part by weight

water-insoluble accelerator, preferably about 1 part by weight

preferably about 5.0 parts by weight of titanium dioxide

preferably about 1.0 part by weight of dispersant

preferably about 25.0 parts by weight of water

The amount of vulcanization paste to be used can vary over a wide range. Usually 10-100 parts by weight, preferably 30-50 parts by weight, and particularly preferably 40 parts by weight are used Vulcanization paste to 100 parts by weight of dry rubber substance.

To produce the vulcanization paste, water and a dispersant or a corresponding one are used

aqueous solution of the dispersant and the other components! admitted.

The mixture and its components then become intense for 12-72 hours, preferably 24 hours mixed and crushed, e.g. B. in a ball mill. on In this way, a ready-to-use vulcanization paste is obtained, which finely divides the constituents Contains shape

The synthetic leather base material obtainable using the vulcanization paste according to the invention, whose excellent property is its water vapor storage capacity, can be known in itself Way to be provided with a top layer, e.g. B. by applying a thin, microporous polyurethane layer It can then be finished in a known manner. It then sets a special high-quality synthetic leather, the properties of which largely correspond to those of natural leather.

example 1

A needled and then shrunk tangled fiber fleece, consisting of 60% polyamide fiber (approx. 40 mm staple length and 1.5 denier), 40% polyester fiber (approx. 40 mm staple length, 1.5 denier) is mixed with an excess of a latex mixture of the composition given below impregnated so that per 100 g of fiber material 100 g of solid are taken up from the latex mixture. The impregnated fleece is then quickly heated to 50 ° C., whereby the latex mixture gels. Thereafter, it is ^{vulcanized with steam for 30 minutes at 105 °} C. and then the fleece is dried in hot air. The fleece is then split so that the end product has the layer thickness given in Table 1. A microporous synthetic leather base material is obtained. The fleece has a storage capacity of 4.4% (determined according to the method given below).

The latex mixture used has the following composition:

210.0 parts by weight of a 47% strength latex of the copolymer of 85% by weight butadiene
and 15 wt% acrylonitrile
(= 100 parts by weight dry substance)
10.0 parts by weight of a 50% by weight silicone oil emulsion (100-1000 cp) in
a 2% aqueous solution
of the condensation product of

1 mole of benzylphenylphenol and
20 moles of ethylene oxide,

1.0 part by weight of a polyether siloxane

8.0 parts by weight of benzylphenylphenol
75.0 parts by weight of water
41.0 parts by weight of a vulcanization paste

2 parts by weight of colloidal sulfur,
5 parts by weight of zinc oxide,

1 part by weight of zinc diethyl dithiocarbamate,

5 parts by weight of titanium dioxide,
1 part by weight of sodium diisopropyldithiocarbamic acid and
27 parts by weight of a 5% strength aqueous solution of a condensation product of naphthalenesulfonic acid with formaldehyde.

The coagulation point of this latex mixture is approx. 40 ° Γ.

Comparative experiment 1

This experiment is carried out in exactly the same way, only is the addition of Siliconöiemulsion and the diisopropyldithiocarbaminsaure sodium (very quick accelerator) dispensed, the vulcanization is also not performed in a steam atmosphere, but in hot air from 110 to 130 ^c C The material thus obtained has a water vapor storage capacity of 0.6%.

The results are summarized in Table 1. For comparison, the corresponding values for Split leather indicated.

Examples 2-4

A tangled fiber fleece consisting of 60% polyamide fiber (approx. 40 mm staple length, 1.5 denier), 40% polyester fiber (approx. 40 mm staple length, 1.5 denier) is impregnated with an excess of a latex formulation of the composition given below so that per 100 g of fiber material 100 g of solid are taken up from the latex mixture. The impregnated fleece is then quickly heated to 50 ° C, whereby the latex mixture gels After 30 minutes at 105 ⁰ C vulcanized with steam and then dried in hot air, the nonwoven. The fleece is then split so that the end product has the layer thickness given in Table 2. A microporous synthetic leather base material is obtained. The fleeces have a water vapor storage capacity of 4-5% (determined according to the method given below; see Table 3).

The latex mixture used has the following composition:

210.0 parts by weight of a 47% strength latex of the copolymer from

60.0% by weight butadiene and 36% by weight acrylonitrile and 4.0% by weight methacrylic acid

(= 100 parts by weight of dry substance),

a) 15 parts by weight of stearyl isocyanate, 33% emulsion, or

b) 15 parts by weight mixture of polyether siloxane with polyethylene,

33% emulsion, or

c) 30 parts by weight of condensation product of methylolated melamine with behenic acid, 16.5% emulsion or

d) 30 parts by weight of polyvinyl methyl ether, molecular weight approx. 50,000, emulsion 16.5%,

1.0 part by weight of a polyether siloxane, 2.0 parts by weight of benzylphenylphenol, 75.0 parts by weight of water
41.0 parts by weight of a vulcanization paste composed of 2 parts by weight of colloidal sulfur, 5 parts by weight of zinc oxide, 1 part by weight of zinc diethyldithio

carbamate,

5 parts by weight of titanium dioxide, 1 part by weight of diisopropyldithiocarbamic acid Sodium and

b5 27 parts by weight of a 5% strength

Solution of a condensation product of naphthalenesulfonic acid with formaldehyde.

The coagulation point of this latex mixture is approx. 40 ^° C

Comparative experiment 2

This experiment is carried out in exactly the same way, only the addition of the rubber and in the other components of the latex insoluble and inert substances and on the diisopropyldithio-

Table

carbamic sodium (very quick accelerator) dispensed, the vulcanization is also not in a steam atmosphere, but in hot air between 100 and 130 ⁰ C. The material thus obtained has a WasserdampfspeicLervermögen performed ϊ of 0.6%. The results are summarized in Tables 2 and 3. For comparison, the corresponding values for split leather are also given.

direction Table I (continued) duration
rigid
ability " Layer thickness
(mm)
according to IUD 4 1% tensile strenght
kp / cm ²
(DIN 53328) Il% Fracture d
tion, %
(DIN 53328) Tear on
strength
kp / cm
(DIN 53329) % Stab pull-out
strength,
kp / cm
(DIN 53329) η. 24 ^h Comparative experiment along
across IUD 20 1.0
1.0 25th 78
97 11.5 90
110 44
39 0.6 69
64 % example along
across < 0.9
0.9 25th 58
106 10.3 90
70 27
35 4.5 62
61 0.6 Split leather along
across Comparative experiment < 1.5
1.5 - 198
203 - 50
50 48
52 5.9 140
130 4.6 example > 6.9 Split leather Elongation ² ' Water vapor absorption
n. 4 " n. 8 ^h Pressure atü 0 / 3.6 0.6 3.2 4.4 - 5.3

Bally flexometer, dry 200,000 kinks (IUD 20) <means: damaged.

> means: not damaged.

Strain, Bally tensometer (IUD 13)

I = linear expansion.

II = permanent expansion.

According to the method described below.

Table 2 direction thickness train fracture Further Themselves- Bend Elongation ² ' In (IUD 13) IUD 4 firm strain, cracked AusrciU- firm
speed ¹ ) pressure 11% (mm) ability, "/» speed. rock wedge. (IUD 20) *: kp / cnr (DIN kp / cm kp / cm (ItU (DIN 53328) *) (DIN (DIN 53328) *) 53329) *) 53329) *) < 25th along 1.0 78 90 44 69 3.6 11.5 Comparison across 1.0 97 110 39 64 < 25th attempt along 1.1 58 90 27 62 3.2 10.3 example across 1.1 106 70 35 61 > - along 1.4 198 50 48 140 - - Split leather across 1.4 203 50 52 130

Bally-Flex "meter, dry 200,000 folds (IUP 20).

<means ¹ damaged.

> means ¹ not damaged

Verdehnu ⁿ g Bally Tcnsomelcr (IUP 13)

I linei'ie elongation.

II Leading distortion :.

This time is for those with the l'orcnem a) -d)

: ncn Synthcscicdcr-Malcrialicn approximately .dcntisch.

Table 3 26 01 after 4 hours 781 after 24 hours 7th 0.6 0.6 Water vapor absorption *) 5.3 6.9 1.4 after 8 hours 3.9 Comparison 1.7 0.6 4.4 attempt 1.5 4.4 Split leather 1.7 6.2 4.8 Example a) 2.1 Example b) 2.2 Example c) 2.7 Example d) 2.2

*) According to the method described below.

The water vapor storage capacity was determined as follows: storage of 4, 8 and 24 hours was recovered

determined: The test specimens (size 50 χ 20 mm) were measured and the weight increase accurate to 0.0001 g

the 24 hours at 2O ⁰ C in a climatic chamber with determined.

a relative humidity of 65%. The result of the measurement is the percentage weight increase

They were then weighed exactly (to the nearest 0.0001 g) and me, based on that after conditioning

then given in a climatic chamber with a relative j-, obtained weight. The measurement results are

Air humidity of 86% at 20 ° C. Based on an average of three individual results.

Claims (2)

Patent claims: 1. Vulcanization paste made from (A) known fillers, (B) sulfur, (C) zinc oxide and (D) vulcanization accelerator and (E) water and (F) a dispersant, characterized in that that the component (D) consists of a water-insoluble vulcanization accelerator and a very fast-acting, water-soluble vulcanization accelerator 2. Vulcanization paste according to claim 1, consisting of