Poromeric synthetic leathers

Details Poromeric synthetic leathers Poromeric synthetic leathers

1999-06-04

2001-05-15

Cameron, Erma (Department: 1762)

Coating processes

With post-treatment of coating or coating material

Chemical agent applied to treat coating

C427S342000, C427S353000, C427S354000, C427S389900, C428S423700, C521S061000, C521S063000, C521S092000, C521S093000, C521S094000, C521S097000, C524S591000, C524S839000, C524S840000, C525S123000, C525S129000, C525S130000, C525S131000, C525S453000, C525S460000, C528S071000, C528S488000, C528S489000, C528S492000

Reexamination Certificate

active

06231926

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing poromeric synthetic leather, which comprises:
I. producing an essentially nonporous impregnate by impregnating a textile sheet material with an aqueous polyurethane dispersion and drying, and
II. producing a poromeric synthetic leather from the impregnate by subjecting the impregnate to the action of an aqueous solution of a Brønsted base. The present invention further relates to these poromeric synthetic leathers themselves.
2. Description of the Background
Poromeric synthetic leathers should in their property spectrum come very close to that of high grade natural leather varieties, especially suede leather. This applies particularly to properties such as good water vapor permeability, a high tear strength and pleasant haptic properties.
The production of poromeric synthetic leather is common knowledge (cf. Kunststoffhandbuch, Carl Hanser Verlag, Munich, Vienna, vol. 7:
Polyurethane,
3rd edition 1993, chapter 10.2.1.4). Prior art processes all produce their synthetic leathers from solutions or dispersions of polyurethanes which contain organic solvents. For example, in the coagulation process, a textile sheet material is impregnated with an organic solution of a polyurethane, optionally in a mixture with a polyurethane dispersion and optionally a polyelectrolyte, and the sheet material thus pretreated is then passed successively through a plurality of baths comprising mixtures of dimethylformamide and water with decreasing dimethylformamide concentration.
One variant of this process, which leads to textile articles having a particularly pleasant, leatherlike hand, is described in JP 09/18 89 75. A polyester web is impregnated with a solution of a thermoplastic polyurethane in DMF/toluene and then treated with aqueous sodium hydroxide solution. The synthetic leather obtained possesses the flexibility of natural leather.
The disadvantage with these processes is that they produce large quantities of waste air or water which contain organic solvents and have to be worked up in a complicated manner.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide poromeric synthetic leathers which, with regard to their performance characteristics, differ as little as possible from natural leather varieties and are simpler to produce than prior art poromeric synthetic leathers.
We have found that this object is achieved by the poromeric synthetic leathers described at the beginning and by the processes for producing them.


REFERENCES:
patent: 53-028773 (1978-03-01), None
patent: 53-062804 (1978-06-01), None
patent: 54-101403 (1979-08-01), None
Chemical Abstract, Accession No. 127: 150058e, JP 09, 188, 975, Jul. 22, 1997.
Kunststoff Handbuch Band 7: Polyurethane, pp. 446-447. Carl Hanser Verlag München Wien, 3. Auflage 1993 (with partial English Translation).

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