JPH0519565B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION The present invention relates to polyurethane elastomers, particularly polyurethane elastomer compositions with increased flexibility using aliphatic or cycloaliphatic polyisocyanates. (Prior art) Polyurethane elastomers have good elasticity, excellent mechanical properties, abrasion resistance, and durability, so they are used in molded products, paints, coatings, sealants, adhesives, binders, printing inks, etc. It is widely used industrially. Among these, when aliphatic or alicyclic polyisocyanates are used as raw materials, their reactivity toward hydroxyl groups is low, so the polyisocyanate and polyol are first reacted by heating to form preforms with NCO groups at the ends. A polyurethane elastomer is produced by synthesizing a polymer and then reacting the prepolymer with a polyamine curing agent. (Problems to be solved by the invention) As a polyamine curing agent, 3,3'-dichloro-
4,4'-diaminodiphenylmethane (MOCA),
Isophorone diamine (IPDA) etc. are used, but
The properties of the polyurethane elastomer obtained are constant. If a polyurethane elastomer with even more flexible properties is required, the composition of the polyol in the prepolymer must be changed, but this is an extremely troublesome operation and difficult to carry out during molding and construction of the polyurethane. Another possible method is to increase the amount of the amine curing agent and lower the equivalent ratio of NCO groups to NH ₂ groups, but this is difficult to implement because the mechanical properties of the obtained polyurethane elastomer are completely deteriorated. (Means for Solving the Problems) The present inventors conducted various studies aimed at increasing the flexibility of the obtained polyurethane elastomer in the curing stage of the prepolymer without degrading the properties of the obtained polyurethane elastomer. , discovered that aminobenzylamine is effective, and arrived at the present invention. That is, the present invention has aliphatic or alicyclic NCO at the terminal.
When curing a prepolymer having groups o
A polyurethane composition with increased flexibility characterized by using one type or a mixture of two or more types of -, m-, p-aminobenzylamine. The benzylamine used in the present invention is o-aminobenzylamine, m-aminobenzylamine, p-aminobenzylamine,
-aminobenzylamine or a mixture of two or three thereof. Aminobenzylamine can be used in combination with other polyamines such as IPDA, MOCA, etc. Especially liquid P at room temperature.
- In addition to aminobenzylamine, a mixture of aminobenzylamines or a mixture of aminobenzylamine and other polyamines is liquid at room temperature, which is extremely advantageous because it can be mixed with a prepolymer at room temperature and immediately molded or constructed. . The organic polyisocyanates used in the production of the prepolymer in the present invention include, for example, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), methylcyclohexane diisocyanate (HTDI), xylylene diisocyanate (XDI), These include hydrogenated xylylene diisocyanate (HXDI), dimers, trimers, carbodiimide-modified products, Biuret-modified products, etc. These aliphatic or alicyclic polyisocyanates can be used alone or in a mixture of two or more, and aromatic polyisocyanates such as tolylene diisocyanate (TDI), crude tolylene diisocyanate, diphenylmethane diisocyanate (MDI) ), polymethylene polyphenyl polyisocyanate, etc. In the present invention, the polyol used to produce the prepolymer is water, polyhydric alcohol such as ethylene glycol, propylene glycol, glycerin, trimethylolpropane, and pentaerythritol, and one of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc.
Polyether polyol obtained by addition polymerization of one or more species, polytetramethylene ether glycol, polyester polyol obtained by reacting polycarboxylic acid such as adipic acid with low molecular weight polyol such as butanediol, and caprolactone. These are polyester polyols and higher fatty acid esters containing OH groups such as castor oil. Furthermore, polymer polyols obtained by graft polymerizing ethylenically unsaturated compounds such as acrylonitrile, styrene, and methyl methacrylate to the above-mentioned known polyether polyols or polyester polyols, and 1,2- or 1,4-
Polybutadiene polyols or hydrogenated versions thereof can also be used. The average molecular weight of these polyols is usually 200 to 10,000, particularly preferably 300 to 7,000. If necessary, a low-molecular polyhydric alcohol such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, hexanediol, glycerin, trimethylolpropane, hexanetriol, etc. may be mixed with the polyol. It can also be used. When producing a prepolymer, a polyisocyanate, a polyol, and, if necessary, a polyhydric alcohol are mixed and reacted at, for example, 30 to 120°C to form a prepolymer. At that time, in the polyisocyanate
NCO groups and OH in polyols and polyhydric alcohols
The appropriate equivalent ratio (NCO/OH) with the group is 1.3 to 10.
Free NCO groups contained in the prepolymer range from 0.5 to 15
Weight % (In the present invention, unless otherwise specified, % means weight %)
). Further, when producing the prepolymer, a plasticizer and a solvent described later may be added in order to adjust the viscosity. Examples of plasticizers used in the present invention if necessary include:
Dioctyl phthalate (DOP), dibutyl phthalate (DBP), dilauryl phthalate (DLP),
Butyl pendyl phthalate (BBP), dioctyl adipate (DOA), diisodecyl adipate (DIDA), trioctyl phosphate (TOP), trischloroethyl phosphate (TCEP), trisdichloropropyl phosphate (TDCPP), propylene glycol adipate Polyester, butylene glycol adipate polyester, epoxy alkyl stearate, epoxidized soybean oil, etc. are used alone or in combination. The amount used is preferably 5 to 100 parts per 100 parts by weight of the prepolymer (in the present invention, parts indicate parts by weight). If necessary, fillers used in the present invention include, for example, carbon black, calcium carbonate, talc, clay, zeolite, diatomaceous earth, perlite, vermiculite, titanium dioxide, etc., singly or in combination. The amount used is preferably 20-100 parts per 100 parts of prepolymer. Other auxiliary agents used as necessary in the present invention include solvents, catalysts, thixotropic agents, stabilizers, adhesion promoters, and the like. Examples of solvents include aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane, heptane, and octane; petroleum solvents ranging from gasoline to kerosene fraction; and esters such as ethyl acetate;
Ketones such as methyl ethyl ketone; ether esters such as cellosolve acetate are used. As the catalyst, any catalyst commonly used in the production of polyurethane can be used. For example, tertiary amines such as N-methylmorpholine, triethylamine, N,N,N′,N′-tetramethylpropanediamine, bis(2-dimethylaminoethyl)ether, and lead octoate,
Organometallic compounds such as lead naphthenate, tin octoate, and dibutyltin dilaurate are used alone or in combination. As the thixotropic agent, for example, colloidal silica, hydrogenated castor oil, organic bentonite, tribenzylidene sorbitol, surface-treated precipitated calcium carbonate, etc. are used. Examples of stabilizers include trade names Irganox 1010 and 1076 (manufactured by Ciba Geigy), Yoshinox BHT, BB, and GSY-930 (manufactured by Yoshitomi Pharmaceutical Co., Ltd.).
Positionally hindered phenols such as tinuvin P,
Benzotriazoles such as 327 and 328 (manufactured by Ciba Geigy); benzophenones such as Tomisorp 800 (manufactured by Yoshitomi Pharmaceutical); Sanol LS-770 and 744;
Positionally hindered amines such as Tinupin 144 (manufactured by Ciba Geigy) are used. In carrying out the present invention, aminobenzylamine is mixed with a solvent, a plasticizer, a filler, a catalyst, etc. as necessary to form a curing agent. After the curing agent is mixed with the prepolymer, it is injected into the mold. The mixing ratio of the prepolymer and the curing agent is such that the equivalent ratio of NCO groups in the prepolymer to NH ₂ groups in the curing agent is 0.9 to 1.1. After leaving the mold at room temperature or under heating, the cured polyurethane molded product is removed. It is also possible to use a spraying device to spray paint the object at the same time as mixing. Furthermore, a thermoplastic polyurethane solution can be prepared by reacting the prepolymer with aminobenzylamine and used as a binder, printing ink, etc. (Function) By using aminobenzylamine as a curing agent, the flexibility of the polyurethane elastomer can be increased. (Example) The present invention will be specifically explained with reference to Examples below. The flexibility of the cured polyurethane elastomer was compared by measuring the tensile modulus and hardness according to JIS K6301. Example 1 Polyester diol 364 with a molecular weight of 1000 obtained by reacting adipic acid and 1,4-butanediol
g isophorone diisocyanate (IPDI) 130.5
A prepolymer having an NCO group content of 3% was synthesized by reacting with g at 80°C for 2 hours. 18.3g of p-aminobenzylamine, 7.8g of isophoronediamine (IPDA) and methyl ethyl ketone
After dissolving in 520g, it was reacted with the prepolymer at 70°C for 1 hour. The physical properties of the film obtained by pouring the obtained polyurethane polymer solution onto a glass plate and evaporating the methyl ethyl ketone were as shown in Table 1. Comparative Example 1 29.7 g of isophorone diamine was dissolved in 520 g of methyl ethyl ketone, and 70 g of the prepolymer of Example 1 was dissolved.
The reaction was carried out at ℃ for 1 hour. This was treated in the same manner as in Example 1, and the physical properties of the film obtained were as shown in Table 1.

[Table] Example 2 527 g of polytetramethylene ether glycol with a molecular weight of 1000, 47 g of butanediol, 240 g of isophorone diisocyanate (IPDI), and 186 g of tolylene diisocyanate (TDI) were reacted at 80°C for 3 hours, resulting in an NCO group content of 8.8% and a viscosity of 61000cps/25
℃ prepolymer was obtained. Aminobenzylamine mixture 122 that is liquid at room temperature
g was mixed with 1000 g of the above prepolymer at room temperature, immediately poured into a mold, and heated and cured at 80° C. for 1 hour.
The physical properties of the polyurethane elastomer obtained by further post-curing at 80° C. for 24 hours after demolding were as shown in Table 2. Comparative Example 2 1000 g of the prepolymer obtained in Example 2 was heated to 80°C. Curing agent 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA) 266g at 120℃
It was heated and melted. Both were mixed, poured into a mold preheated to 80°C, and cured by heating at the same temperature for 1 hour. The physical properties of the polyurethane elastomer obtained by further post-curing at 80° C. for 24 hours after demolding were as shown in Table 2.

【table】

[Table] (Effect of the invention) As is clear from Table 1, the addition of p-aminobenzylamine lowers the 100% and 200% modulus, but there is no significant difference in tensile strength and elongation. Moreover, as is clear from Table 2, by using the aminobenzylamine mixture, the hardness can be increased to 100%.
and 200% modulus decrease, but tensile strength and elongation do not decrease. That is, the present invention makes it possible to increase the flexibility of polyurethane elastomers without deteriorating their mechanical properties.

Claims (1)

[Claims] 1 When curing a prepolymer having an aliphatic or alicyclic NCO group at the end, o-, m-,
A polyurethane elastomer composition with increased flexibility, characterized in that it uses one or a mixture of two or more p-aminobenzylamines.