SU1509382A1 - Polysterurethane compound for making microporous films - Google Patents

Abstract

The invention relates to polyetherurethane compositions and can be used in the field of producing microporous films, coatings of the front layers of synthetic leathers. The invention allows to obtain low-modulus microporous films with improved hygienic properties due to the use of polyetherurethane based on a mixture of polyoxypropylene glycol and polyoxymethylglycol with mol.m. 1000 at their molar ratio of 95: 5 or 90:10 or a mixture of polyoxypropylene glycol with mol.m. 2000 and polyoxymethylene glycol with mol.m. 1000 at a molar ratio of 90:10 using ethylene glycol (12-14 parts by weight) as the chain extender, dimethylformamide (77-79 parts by weight), powdered cellulose / 6-8 parts by weight / as filler and as an additive hydroxyethylene dimethylsiloxane block copolymer / 1-3 parts by weight /. 3 tab.

Description

The invention relates to compositions based on polyether urethanes and can be used in the field of producing microporous films, coatings for the front layer of synthetic leather.

The aim of the invention is to produce / low modulus (films with improved hygienic properties.

The basis of the composition is low modulus polyetherurethane (the initial modulus at tensile strength of 4.2-5.0 MPa) based on a mixture of polyoxypropylene glycol with mol.m. 1000-2000 with polioxytramethylene glycol mol.m. 1000 at their molar ratio of 95: 5 or 90:10, 4,4-diphenylmethane diisocyanate and ethylene glycol as a chain extender.

Polyetherurethane is prepared by a prepolymer method. The polyester is first reacted with an excess of 4,4-diphenylmethane diisocyanate in solution or without solvent at 50-80 ° C. This stage can also occur when using catalysts, sang

with

Od

00 to

3150

An example of organotin in an amount of 0.01-0.05 wt.%.

In the second stage of the process, a stoichiometric solution is added to the solution of the isocyanate-containing prepolymer. or with a small excess amount of low molecular weight glycol chain extender — ethylene glycol and 0.2 wt.% organotin catalyst. ra. After that, a portion of the diisocyanate-containing component is added to the solution of the resulting low molecular weight polyurethane, which can be used as the initial prepolymers or monomeric diisocyanates to obtain high molecular weight polyetherurethane.

The molecular weights of the polyesters used are from 1000 to 2000. associated with the fact that the use of polyoxypropylene glycol mol. masses less than 1000 sharply worsens the complex of physicomechanical, sanitary-hygienic and operational properties of polyetherurethane. The use of polyoxypropylene glycol mol.m. more than 2000 makes it difficult to synthesize polyetherurethane, since such oligomers have a high concentration of monofunctional impurities, which increase sharply with increasing molecular weight of the polyester, which does not allow to obtain high molecular weight polyetherurethanes on their basis.

The addition of 5–10 wt% polyoxide ramethylene glycol improves the performance characteristics of polyetherurethane, especially at lower temperatures. The molar ratio of polyester, ethylene glycol and 4,4 - diphenyl methane diisocyanate for polyoxypropylene glycol mol.m. 1000 is characterized by: a ratio of fcJCO: OH of 2-3: 1, and for polyoxypropylene glycol with mol.m. 2000 NCO: OH 2.5-3: 1. The softness of the obtained polyether urethanes is characterized by their modules, given in Table 1.

As a filler powder cellulose. characteristics of cellulose Content of the main substance,% - Average degree of polymerization Specific surface, cm / g

Bulk weight

pH of an aqueous solution of 5 + 1 As a modifier, hydroxyethylene dimethylsiloxane block copolymer of the general formula is used

CHj, -CH20 (CH CHzO} aH

g 5

0 5

five

0

0

45

50

55

800-3000 cP

7.5-10 6.0-8.0

1.04-1.05 0.9

where m 5-6, and 75-80, p 10-11, mol. m. 8500-10000, the receipt of which is described in a known source with the following properties:

Viscosity at

20 С, сП

The content of silicon,%

ph

Density at

25 C; g / cm3

The content of ON groups,%

The parameters of the structure of oxystilenedimethylsiloxane block copolymers are listed in Table 2.

The composition uses a block copolymer of structure A and B.

To obtain a ROM composition to /. a solution and a modifier are added to a solution of a high molecular weight polyetherurethane at room temperature.

The resulting composition is deaerated.

Microporous films are produced by the method of condensation structure-an. For this, glass with a layer of the composition obtained using a slit die (gap 1 mm) is placed in a precipitation bath. The sediment mixture is 30% dimethyl-fermmamide and 70% water, the precipitating mixture is 40 ° C, the duration of structure formation is 20 minutes. From the precipitating bath, the glass together with the wet microporous film is transferred to the washing bath. The process of washing the microporous films from the solvent is carried out with running water at room temperature for at least 2 hours. Then the film is dried in a free state at room temperature.

The determination of the vapor permeability of microporous films is carried out under isothermal conditions at 28 ° C. Determination of hygroscopicity and moisture recovery of microporous films is carried out according to GOST 8971-78.

Table 3 presents the dependence of the hygienic properties of microporous films on the composition of the composition.

Claims (1)

Invention Formula A polyetherurethane composition for the preparation of microporous films, including polyetherurethane based on polyoxypropylene glycol, 4,4-diphenyl methane diisocyanate and chain extender, Dimethylforma, filler and additive, characterized by In order to obtain low-modulus films with improved hygienic properties, it contains polyetherurethane based on a mixture of polyoxypropylene glycol and polyoxymethylene glycol with mol.m. as polyetherurethane. 1000 at their molar ratio of 95: 5 or 90:10, respectively, or a mixture of polyoxypropylene glycol with mol.m. 2000 and polyoxytetramethylene glycol mol.m. 1000 at a molar ratio of 90:10 using ethylene glycol as a chain extender, it contains powdered cellulose as a filler, and hydroxyethyl lendimethylsiloxane block copolymer of total fsmu 0 50 five wearing 95: 5 or 90:10, respectively, or mixtures of polyoxypropyl glycol with mol.m. 2000 and polyoxy-12-14 tetramethylene glycol mol.m. 1000 at a molar ratio of 90:10 using ethylene glycol as an extension chain. Dimethylformam D77-79 Powder Cellulose6-8 Hydroxyethylenemethylsiloxane block copolymer1-3 Table 1 sn, CHj-Si-O CH, SNG-SNGO (CHf SNG-0 L where ha 5-6, and 75-80, with the following ratios, mac.h. : Polyetherurethane based on a mixture of polyoxypropylene glycol and polyoxytetramethylene glycol, mol.m., 1000. at their molar ratio. B in in ki And X o X - " “G 7. &. 1 o g g 00 W: | "d-IS  S H T-SS.fSg with; 1 o X and P i § I i . sftfajie l .ft. in o d o in g "" Ioko- "Zyyo og" Mog41gs; „EtsoZyoFi“ In In Rtz-Khtochag HN1lo  F i 16 :; l t g 1st, t s 3 (in “about and with Igj & d and 3 k from 9 o