JPH0446967B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an ultra-soft polyurethane elastomer, and more particularly to a method for producing an ultra-soft polyurethane elastomer with improved heat resistance. Polyurethane elastomer has superior mechanical strength and abrasion resistance compared to rubber, and has good weather resistance and chemical resistance, and can withstand long-term use. It has also been widely used in printing rolls, solid tires, etc. In particular, polyurethane elastomers have recently begun to be used in a wide range of applications, such as as vibration-proofing materials and shock-absorbing materials, by taking advantage of their flexibility. Polyurethane elastomers used for such purposes are required to have particularly flexible physical properties and must have extremely low hardness.

A conventionally known method for producing such an ultra-soft polyurethane elastomer is a method in which a high molecular weight polyether diol is used and an amount of polyisocyanate corresponding to 0.2 to 0.8 of the theoretical corresponding amount is reacted. In the ultra-soft polyurethane produced by such a method, polymer chains are not sufficiently formed due to the insufficient amount of isocyanate. Therefore, at room temperature, the elastomer retains its own shape and has vibration absorbing properties, but when used at high temperatures or when the temperature of the elastomer rises due to heat generation due to vibration, the load-bearing capacity decreases and the elastomer collapses. It was hot.

The inventors of the present invention have conducted various studies to improve this point and produce an ultra-soft polyurethane elastomer with heat resistance, and have found that if a polyurethane polymer chain with ultra-soft physical properties is formed by using a trifunctional or higher functional polyol, the objective can be achieved. The inventors have discovered that a product can be obtained and have arrived at the present invention.

That is, in the present invention, when producing a polyurethane elastomer by reacting a polyol and a polyisocyanate, a low molecular weight triol having an average molecular weight of 500 to 1500 or a sum of the low molecular weight triol and a low molecular weight diol having an average molecular weight of 500 to 1500 containing an aromatic ring is used. This is a method for producing an ultra-soft polyurethane elastomer, characterized in that the molar ratio between the amount of polyol and the high molecular weight polyol having an average molecular weight of 2,000 to 6,000 is from 35:65 to 70:30.

Among the polyols used in the present invention, low molecular weight triols include glycerin, hexanetriol,
Trihydric alcohols such as trimethylolpropane and triethanolamine, and in addition to these compounds, aminophenol, aminonaphthol, phenol formaldehyde condensate, phloroglucin, etc. are used as initiators, and one of ethylene oxide, propylene oxide, butylene oxide or Average molecular weight 500 obtained by addition polymerization of two or more types
~1500 polyether polyol. You can also add glycerin, hexanetriol, trimethylolpropane or a mixture of these to adipic acid,
It is a polyester triol with an average molecular weight of 500 to 1,500 obtained by condensation with a dibasic acid such as phthalic acid and a dihydric alcohol such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butylene glycol.

Furthermore, esters of ricinoleic acid and trihydric alcohols, such as castor oil, can also be used.

These low molecular weight triols may be used alone or in combination of two or more.

The low molecular weight diol containing an aromatic ring used in the present invention is divalent phenols such as dihydroxy diphenylpropane, dihydroxy diphenylmethane, dihydroxy diphenyl ether, dihydroxy biphenyl, hydroquinone, resorcinol, naphthalene diol, or aniline, naphthylamine. , monoprimary amines having an aromatic ring such as benzylamine, and one of ethylene oxide, propylene oxide, and butylene oxide.
Molecular weight 400 obtained by addition polymerization of a species or two or more species
1500 to 1500 polyether diol. Also usable are polyester diols having a molecular weight of 400 to 1500 obtained by condensing phthalic acid, isophthalic acid, or terephthalic acid with dihydric alcohols such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, and dipropylene glycol. Furthermore, a polymer polyol with a molecular weight of 400 to 1500 is obtained by graft polymerizing styrene to a polyether diol obtained by addition polymerizing one or more of ethylene oxide, propylene oxide, and butylene oxide to water, ethylene glycol, propylene glycol, etc. can also be used.

These low molecular weight diols may be used alone or in combination of two or more.

In the present invention, when a low molecular weight triol and the following high molecular weight polyol are used in combination,
There are cases where a combination of three types of low molecular weight triols, low molecular weight diols containing aromatic rings, and high molecular weight polyols are used. In either case, the total amount of low molecular weight triol or low molecular weight triol and low molecular weight diol containing an aromatic ring is 35 to 70 mol%, and the high molecular weight polyol is 65 to 30 mol%.
Mol% is preferred.

If it exceeds this range, the hardness of the polyurethane elastomer will increase and its ultra-softness will be lost. Further, below this range, the strength and heat resistance of the elastomer decreases, making it impossible to put it into practical use.

Among the high molecular weight polyols, those suitable for the present invention are di- to octa-functional polyether polyols or polyester polyols whose molecular weight is
2000 to 6000 is appropriate. Among these high molecular weight polyether polyols, those used in the present invention include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butylene glycol, dihydroxy diphenylpropane, glycerin, hexanetriol, trimethylolpropane, and pentaerythritol. , sorbitol, sucrose, dipropylene glycol, methyldiethanolamine, ethyldiisopropanolamine, triethanolamine, ethylenediamine, hexamethylenediamine, bis(p-aminocyclohexane), tolylenediamine, diphenylmethanediamine, naphthalenediamine, etc. with ethylene oxide. , propylene oxide, butylene oxide, styrene oxide, etc. (hereinafter simply referred to as alkylene oxide).

Examples of high molecular weight polyester polyols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1-3- or 1,4-butylene glycol, neopentyl glycol, 1,6-hexamethylene glycol, decamethylene Glycol, bisphenol A, bisphenol F, p-xylylene glycol, 1.
One or more of 4-cyclohexanediol, 1,4-cyclohexanedimethanol, glycerin, trimethylolpropane, hexanetriol, alkylene oxide adduct of pentaerythritol, malonic acid, maleic acid, succinic acid, adipine acids, glutaric acid, pimelic acid, sebacic acid, oxalic acid, phthalic acid, isophthalic acid,
Polyester polyols from one or more of terephthalic acid, hexahydrophthalic acid, etc., or propiolactone, butyrolactone,
Polyols produced by ring-opening polymerization of cyclic esters such as caprolactone; furthermore, polyester polyols produced from the above polyols and cyclic esters, and polyester polyols produced from the above polyols, dibasic acids, and three types of cyclic esters can be used.

As the high molecular weight polyol used in the present invention, 1,2-polybutadiene polyol, 1,4-
Polybutadiene polyol, polychloroprene polyol, butadiene-acrylonitrile copolymer polyol, polydimethylsiloxane dicarbinol, and the like can also be used.

In addition to the above, polytetramethylene ether glycol can also be used.

Furthermore, polymer polyols obtained by graft polymerizing ethylenically unsaturated compounds such as acrylonitrile, styrene, and methyl methacrylate to the above-mentioned polyether polyols or polyester polyols can also be used.

These high molecular weight polyols may be used alone or in combination of two or more.

The organic polyisocyanate used in the present invention is, for example, 2,4-tolylene diisocyanate, 2,6
-Tolylene diisocyanate and mixtures thereof (TDI), diphenylmethane-4,4'-diisocyanate (MDI), naphthalene-1,5-diisocyanate (NDI), 3,3'-dimethyl-4,4'-
Biphenylene diisocyanate (TODI), xylylene diisocyanate (XDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated
MDI), isophorone diisocyanate (IPDI),
Hexamethylene diisocyanate (HDI), hydrogenated xylylylene diisocyanate (HXDI), crude TDI, polymethylene polyphenyl isocyanate (crude MDI), and isocyanurate-modified products, carbodiimidation-modified products, biuret-modified products of these isocyanates, etc. It is.

The amount of organic polyisocyanate used is determined by the amount of NCO groups contained in it and the amount of OH contained in the polyol.
The ratio should be 0.4 to 1.4 equivalents, more preferably 0.5 to 1.2 equivalents, based on the total amount of groups. If it exceeds this range, the polyurethane elastomer will not lose its flexibility, and if it falls below this range, the physical properties of the polyurethane elastomer will deteriorate.

These isocyanates may be used alone or in combination of two or more. When using it, you can use it as is, or once it has been made into a prepolymer,
There are cases where it is used. In the case of prepolymerization, a portion of the NCO groups is reacted with the above-mentioned polyols to form a prepolymer, which is then used for molding. Since the prepolymer method forms polyurethane polymer chains in an orderly manner, it often has a positive effect on the physical properties of ultra-soft polyurethane.

Known urethanization catalysts can be used in carrying out the present invention. Among these catalysts, examples of tertiary amines include triethylamine, tripropylamine, triisopropanolamine, triptylamine, trioctylamine, hexadecyldimethylamine, N-methylmorpholine, N-ethylmorpholine, and N-ethylmorpholine. -octadecylmorpholine, monoethanolamine,
diethanolamine, triethanolamine, N
-Methyldiethanolamine, N,N-dimethylethanolamine, diethylenetriamine, N,
N,N',N'-tetramethylethylenediamine,
N,N,N',N'-tetramethylpropylenediamine, N,N,N',N'-tetramethylbutanediamine, N,N,N',N'-tetramethyl-1,
3-butanediamine, N,N,N',N'-tetramethylhexamethylenediamine, bis[2-(N,
N-dimethylamino)ethyl]ether, N,N
-dimethylbenzylamine, N,N-dimethylbenzylamine, N,N-dimethylcyclohexylamine, N,N,N',N'',N''-pentamethyldiethylenetriamine, triethylenediamine, formate and other salts of triethylenediamine , amino group oxyalkylene adducts of primary and secondary amines, azacyclic compounds such as N,N-dialkylpiperazines, various N,N',N''-trialkylaminoalkylhexahydrotriazines, Tokkosho These include the β-aminocarbonyl catalyst of No. 52-43517 and the β-aminonitrile catalyst of Japanese Patent Publication No. 53-14279.

Examples of organometallic urethanation catalysts include tin acetate, tin octoate, tin oleate, tin laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, lead octoate, and lead naphthenate.

A variety of organic and inorganic fillers and pigments can be used in the present invention.

Among these, examples of inorganic substances include calcium carbonate, talc, clay, mica, graphite, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, calcium sulfate, zinc oxide,
Examples include aluminum oxide, titanium oxide, iron oxide, silicic anhydride, glass flakes, carbon black, silica, and rock wool. These shapes are powder-like, scaly-like, and fibrous-like, and can be used as is, but the physical properties of ultra-soft polyurethane can be improved by subjecting the surface to titanium treatment, silicone treatment, etc. .

Organic materials include bitumen, pine resin, resin powder, wood flour, animal and plant fibers, and artificial fibers.

In addition to the above, minute hollow spheres such as silica balloons, glass balloons, phenolic resin balloons,
Vinylidene chloride resin balloon, Shirasu balloon,
Bar lights can also be used.

Plasticizers can be used in the present invention. These plasticizers include, for example, dibutyl phthalate, dioctyl phthalate, tricresyl phosphate, tris(2-chloroethyl) phosphate,
Tris (chloropropyl) phosphate, tris (2,3-dichloropropyl) phosphate, tris (2,3-dibromopropyl) phosphate, dioctyl adipate, dibutyl sebacate, and the like.

Furthermore, in the present invention, one or more of antioxidants, ultraviolet absorbers, and ultraviolet stabilizers may be used as stabilizers in order to increase the durability of the product.

Positionally hindered phenols are used as antioxidants, such as the trade names Irganox 1010, Irganox 1076 (manufactured by Ciba Geigy), and the trade names Yoshinox BHT, Yoshinox BB, Yoshinox GSY-930 (manufactured by Yoshitomi Pharmaceutical Co., Ltd.). Equivalent to.

As the ultraviolet absorber, for example, benzotriazoles such as Tinuvin P, Tinuvin 327, and Tinuvin 328 (manufactured by Ciba Geigy), or benzophenones such as Tomisorp 800 (manufactured by Yoshitomi Pharmaceutical Co., Ltd.) can be used.

Preferable examples of the UV stabilizer include positionally hindered amines such as Sanol LS770, Sanol LS744, and Tinuvin 144 (manufactured by Ciba Geigy), or Tinuvin 120 and Irgastab 2002 (manufactured by Ciba Geigy).

In addition to the various additives mentioned above, physical properties can be improved by adding silicone or titanium coupling agents to increase the affinity of the filler for urethane, and antifoaming agents, surface modifiers, etc. can be added. You can also do it.

To apply the present invention, a high molecular weight polyol, a low molecular weight triol, a low molecular weight diol containing an aromatic ring, a catalyst, a plasticizer, a filler, etc. are mixed with a roll to form a liquid A. This A solution is mixed with polyisocyanate, poured into a mold at room temperature to 70℃, and heated to 80 to 90℃.
After heating at ℃ for 10 to 30 minutes, the cured elastomer is removed from the mold.

Among the physical properties of the obtained ultra-soft polyurethane elastomer, hardness was measured using the C scale of an Asker hardness meter, and other mechanical strengths were measured according to JIS K-6301.

These elastomers are extremely flexible and have a hardness of C5
to C70, 100% modulus 0.5 to 10 Kg/cm ² .

The elastomer according to the present invention does not undergo dimensional changes even after being heated at 70°C or 90°C for several days to two weeks.
There is almost no change in hardness. Therefore, it is possible to exhibit excellent vibration absorption performance for a long period of time at high temperatures.

In contrast, in conventional methods that do not use a mixture of the triol or polyol of the present invention and a diol containing an aromatic ring, the elastomer deforms in a short time when heated to 90°C, as shown in Reference Example 1 below. Further, as shown in Reference Example 2, an elastomer having a composition intermediate between the conventional method and the method according to the present invention also undergoes deformation at 90°C.

The present invention will be explained in more detail with reference to Examples below.

Example 1 600 g (0.2 mol) of a glycerin-based trifunctional polyether polyol with a molecular weight of 3000, 200 g (0.29 mol) of a glycerin-based polyether triol with a molecular weight of 700, 100 g of dioctyl phthalate, 100 g of calcium carbonate, 2-ethyl After kneading 1 g of lead hexanoate with a roll, the mixture was further heated and stirred under reduced pressure, and the resulting mixture was designated as Liquid A-1.

This A-1 solution was mixed with 110 g of diphenylmethane-4,4'-diisocyanate prepolymer (NCO group content 2 x 8%) and poured into a mold heated to 60°C. After heating this at 90°C for 10 minutes, the cured elastomer was taken out from the mold.

In this example, the molar ratio of low molecular weight triol to high molecular weight polyol was 59:41, and NCO
The equivalent ratio of groups to OH groups was 0.5.

The obtained ultra-soft polyurethane elastomer has a hardness of C15, a 100% modulus of 2.5 Kg/cm ² , and a tensile strength of 20
Kg/cm ² and elongation was 500%.

This ultra-soft polyurethane elastomer block showed no dimensional change even after being left at 90 DEG C. for two weeks, and its hardness after heating was C-15.

Example 2 Molecular weight 2000 based on ethylene glycol
540 g (0.27 mol) of bifunctional polyether polyol, glycerin-based molecular weight 3,000
60g (0.02mol) of functional polyether polyol,
20 g (0.03 mol) of a polyether triol with a molecular weight of 700 based on glycerin, 180 g (0.45 mol) of a polyether diol with a molecular weight of 400 based on dihydroxyphenylpropane, 100 g of dioctyl phthalate, 100 g of calcium carbonate, 2-
1 g of lead ethylhexanoate was treated in the same manner as in Example 1 to obtain liquid A-2. This A-2 liquid and 160 g of diphenylmethane-4,4'-diisocyanate prepolymer used in Example 1 were treated in the same manner as in Example 1 to obtain an elastomer.

In this example, the molar ratio of the total amount of low molecular weight triol and low molecular weight diol containing an aromatic ring to the high molecular weight polyol was 62:38, and the
The equivalent ratio of OH groups was 0.7.

The obtained ultra-soft polyurethane elastomer has a hardness of C10, a 100% modulus of 2.0 Kg/cm ² , and a tensile strength of
It weighed 18Kgcm ² and had an elongation of 600%.

This ultra-soft polyurethane elastomer block showed no dimensional change even after being left at 90 DEG C. for two weeks, and its hardness after heating was C-12.

Example 3 2530 g (0.8 mol) of a trifunctional polyether polyol with a molecular weight of 3000 based on glycerin, 100 g (0.07 mol) of a trifunctional polyether polyol with a molecular weight of 1500 based on glycerin, 700 molecular weight based on glycerin 950 g (1.4 mol) of trifunctional polyether polyol, 3020 g of dioctyl phthalate, 3020 g of calcium carbonate, 2-
Lead ethylhexanoate 4g, carbon black 163
A mixture obtained by thoroughly kneading g with a roll and then heating and stirring it in a planetary mixer under reduced pressure.
- Three liquids were used. Take 1000g of this A-3 liquid, 2.
of 4- and 2,6-tolylene diisocyanate
It was mixed with 53.2 g of an 80:20 mixture, poured into a mold heated to 70°C, and heated at 80°C for 10 minutes to harden.

In this example, the molar ratio of low molecular weight triol and high molecular weight polyol was 65:35,
The equivalent ratio of NCO groups to OH groups was 0.9.

The obtained ultra-soft polyurethane elastomer has a hardness of C56 and a modulus of 100. 3Kg/cm ² , tensile strength
The weight was 23Kg/cm ² and the elongation was 420%.

This ultra-soft polyurethane elastomer block showed no dimensional change even after being left at 90 DEG C. for two weeks, and its hardness after heating was C-54.

Example 4 In Example 1, instead of the glycerin-based polyether polyol with a molecular weight of 700, 100 g (0.14 mol) of a triethanolamine-based polyether polyol with a molecular weight of 700 was used to prepare Liquid A-4.

Diphenylmethane-4,4'-diisocyanate prepolymer using this A-4 liquid in Example 1
After mixing with 109 g, an ultra-soft elastomer was prepared in the same manner as in Example 1.

In this example, the molar ratio of low molecular weight triol to high molecular weight polyol was 41:59, and NCO
The equivalent ratio of groups to OH groups was 0.7.

The resulting ultra-soft polyurethane elastomer has a hardness of C24, a 100% modulus of 2.8 Kg/cm ² , and a tensile strength of 20.
Kg/cm ² and elongation was 470%.

This ultra-soft polyurethane elastomer block showed no dimensional change even after being left in an air bath at 90°C for two weeks, and its hardness after being left was C-27.

Example 5 In Example 2, an ultra-soft polyurethane elastomer was obtained by using 180 g (0.45 mol) of an aniline-based polyether diol with a molecular weight of 400 instead of dihydroxydiphenylpropane.

This ultra-soft polyurethane elastomer has a hardness
C10, 100% modulus 1.8Kg/cm ² , tensile strength 18
Kg/cm ² and elongation was 650%.

This ultra-soft polyurethane elastomer block showed no dimensional change even after being left in an air bath at 90°C for two weeks, and its hardness after being left was C12.

Example 6 Liquid A-1 obtained in Example 1 was mixed with 197 g of isophorone diisocyanate, poured into a mold heated to 70°C, and removed from the mold after heating at 90°C for 30 minutes.

In this example, the molar ratio of low molecular weight triol to high molecular weight polyol was 59:41, and NCO
The equivalent ratio of groups to OH groups was 1.1. The obtained ultra-soft polyurethane elastomer has a hardness of C46, 100
% modulus 4.7Kg/cm ² , tensile strength 23Kg/cm ² ,
The growth was 370%.

This ultra-soft polyurethane elastomer block showed no dimensional change even after being left at 90 DEG C. for two weeks, and its hardness after heating was C-47.

Moreover, this ultra-soft polyurethane elastomer block did not change color even after being exposed to ultraviolet light for 500 hours using a fedometer.

Reference example 1 Molecular weight based on propylene glycol
2000 bifunctional polyether polyol 600g (0.3
mol), 200 g (0.5 mol) of polyether diol with a molecular weight of 400 based on propylene glycol, 1 g of lead 2-ethylhexanoate, 100 g of dioctyl phthalate, and 100 g of calcium carbonate were kneaded with a roll, and then heated and stirred under reduced pressure. The resulting mixture was designated as Liquid A-5. This A-5 solution was mixed with 210 g of diphenylmethane 4,4'-diisocyanate prepolymer (NCO group content 28%) and poured into a mold heated to 60°C.

After heating this at 90°C for 15 minutes, the cured elastomer was taken out from the mold.

In this reference example, no triol was used at all, and the equivalent ratio of NCO groups to OH groups was 0.9.

The obtained ultra-soft polyurethane elastomer has a softness of C10, a 100% modulus of 1.9 Kg/cm ² , and a tensile strength of
The weight was 16Kg/cm ² and the elongation was 640%. When this ultra-soft polyurethane elastomer block was left in an air bath at 90°C, it deformed to the point where it retained its original shape in 14 hours. Furthermore, when left in an air bath at 70°C, it softened in 100 hours, making hardness measurement impossible.

Reference example 2 Molecular weight based on propylene glycol
2000 bifunctional polyether polyol 450g
(0.225 mol), molecular weight based on glycerin
3000 trifunctional polyether polyol 150g
(0.05 mol), molecular weight based on glycerin
50 g (0.072 mol) of 700 polyether triol,
Molecular weight 400 based on propylene glycol
150 g (0.375 mol) of polyether diol, 2
- 1 g of lead ethylhexanoate, 100 g of dioctyl phthalate, and 100 g of calcium carbonate were treated in the same manner as in Reference Example 1 to obtain liquid A-6.

Diphenylmethane-4,4'-diisocyanate prepolymer using this A-6 liquid in Reference Example 1
After mixing with 185 g, the same treatment as in Reference Example 1 was carried out to obtain an ultra-soft polyurethane elastomer.

In this reference example, the molar ratio of low molecular weight triol to high molecular weight polyol is 26:74, and NCO
The equivalent ratio of groups to OH groups was 0.8.

The obtained ultra-soft polyurethane elastomer has a hardness of C11, a 100% modulus of 2.1 Kg/cm ² , and a tensile strength of 21.
Kg/cm ² and elongation was 560%.

When this ultra-soft polyurethane elastomer block was left in a heated air bath at 90°C, deformation occurred in 14 hours.

Claims (1)

[Claims] 1 When producing polyurethane elastomer by reacting polyol and polyisocyanate,
The molar ratio of the total amount of a low molecular weight triol with an average molecular weight of 500 to 1500 or a low molecular weight diol with an average molecular weight of 500 to 1500 containing an aromatic ring and a high molecular weight polyol with an average molecular weight of 2000 to 6000 is 35 to 65. A method for producing an ultra-soft polyurethane elastomer characterized by a ratio of 70 to 30.