JPH02263819A - Polyurethane elastomer - Google Patents

Abstract

PURPOSE:To obtain the title elastomer free from lowering of strength, hardness, modulus, abrasion resistance, etc., by using a high-molecular polyoxyalkylenepolyol reduced in an unsaturated group-containing by-product monool. CONSTITUTION:The aimed elastomer obtained by reacting (A) a polyoxyalkylenepolyol having 34-60 hydroxyl number and <=0.03meq/g total unsaturated degree and used as polyol with (B) a polyisocyanate compound (e.g. tolylene diisocyanate). Furthermore, the component A is preferably obtained by adding propylene oxide or ethylene oxide to an initiator such as propylene glycol using a catalyst such as iron chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyurethane elastomer, and is particularly characterized by the use of a high molecular weight polyoxyalkylene polyol with little by-product monool.

[Prior Art] It is widely practiced to produce polyurethane elastomers by reacting polyols with polyisocyanate compounds.

When polyoxyalkylene polyols are used as the bolyl in producing the above polyurethane elastomers, they are generally produced using an alkali metal hydroxide as a catalyst. In this case, a monool having an unsaturated group is produced as a by-product, and the amount of this produced increases with the molecular weight.

In the molecular weight range of hydroxyl value 60 or less, conventional technology
The total unsaturation degree is usually 0.1 oa+eq/g or more,
Since the amount of monol produced increases with molecular weight, it is virtually impossible to produce a polyol with an unsaturation degree of 0.03 meq/g or less.

[Problem to be solved by the invention] Polyoxyalkylene polyols, which have been conventionally used as raw materials for polyurethane elastomers, especially hydroxyl value 60
The following polyols contain unsaturated monools as by-products, and the urethane elastomers produced using them are:
This includes problems such as decreases in strength, elastic modulus, hardness, abrasion resistance, and curing properties.

In order to solve the above problems and improve the performance of elastomers, it is effective to use polyols with low by-products, and it is possible to synthesize polyoxyalkylene polyols with low by-products, which was previously impossible. It is desired to make this possible and to solve the above problems.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and includes a method for producing a polyurethane elastomer by reacting a polyol and a polyisocyanate compound. , total unsaturation 0.03meq/g
The present invention provides a novel polyurethane elastomer characterized in that it is used as an essential component of the following polyoxyalkylene polyol.

The polyoxyalkylene polyol used in the present invention has fewer by-product monools having unsaturated groups than conventional polyols, so it can solve the problems conventionally seen.

These polyoxyalkylene polyols are made by combining polyhydric alcohols, sugars, alkanolamines, polyhydric phenols, and other initiators with cyclic ethers, especially propylene oxide and ethylene oxide, diethylzinc, iron chloride, metal porphyrins, double metal cyanide complexes, etc. can be obtained by adding as a catalyst. The hydroxyl value of these polyoxyalkylene polyols is 34 to 60, and the total unsaturation degree is 0.0.
It is necessary that it is 3 meq/g or less, preferably 0.025 meq/g or less.

As the polyol used in the present invention, any polyoxyalkylene polyol can be used as long as it contains the above-mentioned polyoxyalkylene polyol. For example, polyoxyalkylene polyol alone, polyester polyol, polycarbonate polyol, hydroxyl group-containing polydiene polymer etc. can be used in combination.

In the present invention, only the above-mentioned polyol with a low hydroxyl value (i.e., high molecular weight) (excluding water) can be reacted with an isocyanate compound, but a polyfunctional compound capable of reacting with a low molecular weight isocyanate group can also be reacted with the isocyanate compound. It can be used with high molecular weight polyols.This polyfunctional compound has two or more isocyanate-reactive groups such as hydroxyl groups, primary amino groups, or secondary amino groups, and has a molecular weight per isocyanate-reactive group. is less than 60,0,
In particular, compounds with a molecular weight of 300 or less are suitable. Such compounds include compounds commonly called crosslinking agents or chain extenders. Such compounds include, for example, polyhydric alcohols, alkanolamines, polyamines, and low molecular weight compounds obtained by adding small amounts of alkylene oxide to polyhydric alcohols, alkanolamines, sugars, polyamines, monoamines, polyhydric phenols, etc. There are polyether polyols. Furthermore, low molecular weight polyester polyols can also be used. Preferably, polyhydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, and glycerin, alkanolamines such as jetanolamine and triethanolamine, and polyether polyols having a hydroxyl value of 200 or more are used. The amount of this polyfunctional compound used is not particularly limited, but the amount of high molecular weight polyol 100
The amount is preferably about 1 to 50 parts by weight; if the amount is more than this, the resulting elastomer becomes brittle.
If the amount is too low, the elongation will be high, but the strength will be low, which is not preferable.

Examples of the polyisocyanate compound include aromatic, alicyclic, or aliphatic polyisocyanates having two or more isocyanate groups, mixtures of two or more thereof, and modified polyisocyanates obtained by modifying them. Specifically, for example, tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylisocyanate (commonly known as crude MDI)
) Polyisocyanates such as xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate, as well as prepolymer-type modified products, nurate-modified products, urea-modified products, and carbodiimide-modified products thereof.

The polyurethane elastomer referred to in the present invention refers to a non-foamed elastomer, and when producing a non-foamed elastomer,
It can be obtained by reacting the polyol with the incyanate-reactive group-containing polyfunctional compound and the polyisocyanate compound, if necessary, in the presence of a catalyst.

As the catalyst, a metal compound catalyst such as an organic tin compound or a tertiary amine catalyst such as triethylenediamine is used, which promotes the reaction between the active hydrogen-containing group and the incyanate group.

Regarding the quantitative ratio of the reactants, it is suitably 80 to 130, particularly 95 to 110, expressed as a commonly used isocyanate index.

In the present invention, fillers, stabilizers, colorants,
It is also possible to use additives such as flame retardants. (Thus, the polyurethane elastomer used in the present invention is a polyoxyalkylene polyol with less by-product monools having unsaturated groups, compared to the polyurethane elastomer obtained from conventional polyoxyalkylene polyols with many by-product monools. It has excellent strength, elastic modulus, hardness, wear resistance, etc., and can be used for various purposes.

[Example] The following polyols were synthesized and evaluated as elastomers.

Polyol A: Polyoxypropylene diol with a hydroxyl value of 56 and degree of unsaturation of 0.010 mec+/g by reacting brobylene glycol with propylene oxide Polyol B: A polyoxypropylene diol with a hydroxyl value of 37 and degree of unsaturation by reacting propylene oxide with brobylene glycol 0.015 meq/g polyoxypropylene diol Polyol C: hydroxyl value 56 unsaturation 0.015 meq 7g polyoxypropylene triol made by reacting glycerin with propylene oxide [Example 1] 100 parts of polyol A (parts by weight: below) Similarly) 34 parts of diphenylmethane diisocyanate (MDI) at 80°C
1,4-Buta, diol (1,
4-BD) was added and defoamed, poured into a mold with a thickness of 0.5 mm, and cured at 130° C. for 10 hours.

The tensile strength of the obtained elastomer is 390 kg/cm"
.

Tensile stress at 850% elongation and 2100% elongation 35 kg/c
m”.

Shore A hardness 85. Taper wear test (wear wheel H-2
2 load 1000g, number of rotations 1000 times) wear amount is 16
It was rng.

[Example 2] After reacting 100 parts of polyol B and 72 parts of MEII at 80°C for 3 hours, 1.4-BD was reacted with 21.5 parts at 60°C.
After degassing, an elastomer was obtained in the same manner as in Example 1. Tensile strength 250kg/cm”, elongation 750%,
Tensile stress at 100% elongation: 120 kg/cm2. Shore D hardness 54. The amount of wear was 41 mg.

[Example 3] After reacting 100 parts of polyol C and 35.3 parts of MDI at 80°C for 3 hours, 1.4-BD was reacted with 7.5 parts at 60°C.
After adding 6 parts and defoaming, an elastomer was obtained in the same manner as in Example 1. Tensile strength 170kg/cm", elongation 320%
, the tensile window cuff at 100% elongation was 5 kg/cm'', the Shore A hardness was 87, and the amount of wear was 47B.

[Comparative Example 1] Polyoxypropylene triol, which had the same structure as polyol B and was synthesized by a conventional method, had a hydroxyl value of 37.
．． An elastomer was obtained in the same manner as in Example 2 using an unsaturation degree of 0.065. Tensile strength 120kg/cm", elongation 370%, tensile stress at LOG% elongation 87kg/cm
Rich, Shore D hardness 48. The amount of wear was 65a+g.

[Comparative Example 2] Polyoxypropylene triol, which had the same structure as polyol C and was synthesized by a conventional method, had a hydroxyl value of 37.
．． An elastomer was obtained in the same manner as in Example 3 using an unsaturation degree of 0.070. Tensile strength 140kg/cm", elongation 350%, tensile stress at 100% elongation 40kg/c++
+'', seam A hardness 73, wear amount 85 mg.

[Effects of the Invention] The present invention uses polyoxyalkylene polyols with lower by-product monools (lower degree of unsaturation) than conventional polyols to be used in polyurethane elastomers, thereby improving strength, which was a problem in the past. elastic modulus, hardness,
It has been found that it is possible to solve the problem of deterioration in wear resistance, etc.

Claims (1)

[Claims] 1. A method for producing a polyurethane elastomer by reacting a polyol and a polyisocyanate compound, wherein the hydroxyl value is 34 to 60 and the total unsaturation degree is 0.03 meq/
Polyurethane elastomer 2 characterized by using as an essential component a polyoxyalkylene polyol of not more than 30 g, a compound having two or more isocyanate-reactive groups that can react with isocyanate groups together with the polyol and a molecular weight per isocyanate-reactive group of 600 or less The polyurethane elastomer according to claim 1, which uses