CS238296B1 - Light expanded polyurethan modification method - Google Patents

Abstract

Soft, lightweight polyurethane modified by addition of telechelic liquid rubbers based on butadiene, isoprene or copolymer isobutylene - 1,3 pentadiene having terminal reactive groups at the chain ends terminated with a hydroxyl group an average molecular weight of 800 to 8000 to be added in production to basic polyols in amounts of 5 to 50 parts by weight per base polyol. The addition of said telechelic polymers improvement of physical-mech. values in particular the compression resistance. For polyurethane foams that are used in the furniture industry and industry improvement is desirable those properties in your context with the shape and design of the padded part increases the utility value of this material.

Description

The invention solves a modification of soft polyurethane softening, which brings about an improvement of some of its physiologically mechanical values.

Briefly, polyurethane foams are prepared by reacting aromatic, aliphatic or cycloaliphatic isocyanates with a number of functional groups per molecule greater than 1, with compounds containing more than one active hydrogen per molecule, in the presence of a catalyst, blowing agent, stabilizer, emulsifiers and other additives. * Polyurethane foams can be prepared in a wide range of products »It is known that the physical-mechanical values can be influenced in several ways - for example by selecting the starting components, choosing a bulk weight and a whole range of additives which can shift its values in the viscoelastic properties of the foam. · There are several additives belonging to the second group * There are mainly various fillers of inorganic and organic origin · These fillers, as mentioned, increase the hardness characteristics, but mostly at the same time the reduction of other viscoelastic properties »It is precisely those properties of the foam, as manifested in their hysteresnítfh values are those characteristics which that, when the polyurethane foam applications Snoha prevail»

The invention solves the modification of polyurethane foams by adding telechelic liquid rubbers based on butadiene, isoprene or isobutylene-1,3 pentadiene copolymers having terminal reactive groups at both ends of the chain terminated with a hydroxyl group having an average molecular weight of 800 to 8000. into the polyol part of the recipe already in the production of polyurethane foam in quantities of 5 to 50 parts by weight »per basic polyol *

The main reason ^ is the improvement of some physico-mechanical values, especially compression resistance and hardness according to the added amount of telechelic teflon rubber by 20 to 50% while maintaining proportional viscoelastic values, especially tensile strength and ductility »At the same time, values after hydrolytic aging of foam

It is found that the improvement of the resistance to compression, assessed according to CSN 64 5441, can be increased, for example, at a dosage of 30 wt. d. telechelic liquid rubber, up to about 40%.

As already indicated, the technology for producing soft expanded polyurethane consists in accurately mixing to the desired temperature of the heated liquids. One of the reaction streams, commonly referred to as component A, comprises a polyol, a catalysate, a blowing agent, a stabilizer, an emulsifier, and other materials. The second reaction reaction contains a diisocyanate. Telechelic liquid rubber is added to reaction component A1; in such machinery where it is possible to lead the supply of telechelic liquid rubber directly to the polyol line or directly to the mixing head, this option is then preferred.

The choice of telechelic polymers is relatively wide; the most suitable types are those having a suitable microstructure, controllable functionality and a relatively narrow molecular weight distribution.

According to the proposed process, it is clear that for the production of modified polyurethane foams according to the invention, it is not necessary to substantially change the existing technology. Regarding the composition of the recipe, the amount of isocyanate must be determined with respect to the hydroxyl number of the telechelic polymer and then increased by 5 to 7%. In some processes, particularly in the case of loose-foamed polyurethane foams, but also in some molded foams, it is necessary to increase the feed rate of the crosslinking catalyst. It is possible that some other minor recipe modifications may occur with some types of polyurethane foams having specific conditions.

From the standpoint of evaluating the properties of the soft cellular materials, the soft spiked polyurethane prepared according to the present invention improves some physically-mechanical values to a level that is close to that of foam rubber.

In the case of soft polyurethane foam, which is used as a upholstery material in the furniture industry and in the transport vehicle industry, it is desirable to improve precisely these properties which, in the context of the shape and design of the upholstered part, increase the utility value of this material.

in x «3 w 238 296

Example. 1

For the preparation of the soft expanded polyurethane, 7% by weight of polyetherpolyol (OH number 49 mg KOH / g) were used.

3500), 3% by weight of telechelic polybutadiene rubber (rnolek · 3500, OH content 1.04%), 3.1% water, 0.1% triethylenediamine, 1.0% d · polysiloxane surfactant, 0.2% by weight of tin octoate at a dosage of toluene diisocyanate at an index value of 105 ·

A soft expanded polyurethane with a density of 30 kg / πΡ, compression resistance according to ČSN 64 5441 9.2 kPa, tensile strength and elongation according to ČSN 64 5431 0.14 MPa and 210%, permanent deformation according to ČSN 64 5442 3 were prepared, 2%.

Soft expanded polyurethane complies with the requirements laid on this foamed material.

Example 2!

For the preparation of soft expanded polyurethane, 80 wt.% Of polyetherpolyol (OH No. 35 mg KOH / g, mole.

4500, approx. 50% of primary OH groups), 20 wt. d »liquid telechelic polybutadiene rubber {rnolek · wt. 3500, OH groups content 1.04%), 2.6 wt.% Water, 1.0 wt. 0.2 wt.% triethylenediamine, 0.6 wt.% dimethylethanolamine, 1.0 wt. d · polysiloxane povtchově active agent, 0.15 wt »· d of dibutyltin dilaurate at a dosage of the mixture of diphenylmethane diisocyanate and toluylene diisocyanate in a 1: 1 ratio at an index of 105 · Byljí prepared soft expanded polyurethane with a density of 40 kg / nP, pressure resistance ¹ according to CSN 64 5441 at 40% 4.5 kPa, tensile and elongation strength according to ČSN 64 5431 0.19 MPa and 150%, permanent defoamation according to ČSN 64 5412 2.5

Soft expanded polyurethane complies with the requirements imposed on foam foamed in the form of the so-called cold method.

Example 3

To prepare the expanded polyurethane, 60 wt. d® polyetherpolyol (OH No. 35 mg KOH / g, MW 4800), 35 wt. d · telechelic isoprene rubber {rnolek · wt. 2100, OH groups content 1.01%), 5.0 wt. d. water, 0.7 wt. of detrotamethylbutadiamine, 5.0 wt

238 296 manofltrichloromethane at dosing of diphenylmethane diisyanate in index value 102. A lightweight polyurethane, generally characterized as semi-hard type with a density of 60 kg / nP, compression resistance according to ČSN 64 5441 3.1 kPa, permanent deformation according to ČSN 64 5442 4.7%.

This type meets the requirements for semi-rigid foam with high damping effects.

Example 4 70 wt.% Were used to prepare soft cellular integral polyurethane. d. polyether polyol (OH No. 28 mg KOH / g, molecular weight 6000), 30 wt. d. teleohelic isobutylene of 1.3 pentadiene rubber (mol. wt. 4000, OH content 1.01%), 1.0 wt. d. 33% triethylenediamine solution in propylene glycol, 12 wt. d. monofluorotrifluoromethane, 8.0 wt. d. Methyl chloride, 8.0 wt. d. black pigment paste when dosing a mixture of diphenylmethane diisocyanate with toluene diisocyanate in a ratio of 6; 4 in index value 102.

A soft integral lightweight polyurethane of 160 kg / nP, compression resistance according to ČSN 64 5441 28 kPa, and tensile strength according to dSN 64 5431 65 kPa were prepared.

Soft integral lightweight polyurethane meets the requirements for shaped upholstery with surface bark.

Claims (1)

SUBJECT OF THE INVENTION 238 296 Process for modifying soft expanded polyurethane prepared by reacting bifunctional or multifunctional isocyanates with polyether polyols and / or polyester polyols in the presence of catalysts, water, polysiloxane surfactant and other additives, characterized in that from 100 wt. d. a base polyol of polyetherpolyol and / or polyesterpolyol is replaced by a selected amount in the range of 5 to 50 wt. d. Telechelic liquid rubber based on butadiene, isoprene or hydroxyl-terminated isobutylene-1,3 pentadiene copolymers, having an average molecular weight of 800 to 8000 in an isocyanate index adjustment to hydroxyl content of 102 to 107;