JPH054410B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a method for producing reaction injection molded elastomers and a method for producing polyether polyamines used in carrying out the method. Prior Art The reaction injection molding method, which manufactures urethane bumpers for automobiles by reacting resin materials in a mold, has attracted attention, and U.S. Pat.
Various techniques have been proposed, such as No. 4216543, No. 4246363, and No. 4269945. In this field, a technology that is attracting attention as a technology that can provide reaction injection elastomer molded products with particularly excellent mechanical strength, heat resistance, and other physical properties is an amine-terminated polyether with an average molecular weight of 1500 or more and an amine-terminated chain extender. For example, there is a method described in JP-A-58-188643, in which a polyisocyanate and a polyisocyanate are reacted in a closed mold. However, in the conventional polyurea reaction injection molding method using polyoxyalkylene diamine with a molecular weight of up to about 3000, it has been pointed out that the curing shrinkage rate is large due to the reaction with isocyanate, which causes cracking in the mold during molding. Problems to be Solved by the Invention Therefore, a polyurea reaction injection molded elastomer which is excellent in terms of mechanical strength, heat resistance, etc.
There is a demand for manufacturing molded products that do not cause cracking in the mold, and it is an object of the present invention to meet this problem. Means for Solving the Problems According to the present invention, the above object can be achieved by formula

[expression] or (In the formula, n is an integer of 2 or more, R is an aliphatic or aromatic hydrocarbon or a heterocyclic compound residue) A polyfunctional epoxy compound with an average molecular weight of 270 to 1000 and the formula R'(NH ₂ ) ₂ (wherein R' is polyoxyalkylene) A polyoxyalkylene diamine with an average molecular weight of 240 to 3000 is blended so that the molar ratio of epoxy groups to amino groups is 1:2 to 1:6, and the reaction is carried out. Primary amine equivalent 200-3000, viscosity 200-7000cps
a step of producing a polyether polyamine;
And, it is achieved by a method for producing a reaction injection molded elastomer, which comprises a step of reacting the polyether polyamine, an amine-terminated chain extender, and a polyisocyanate in a closed mold. Instead of directly reacting polyoxyalkylene diamine with polyisocyanate, the present inventors previously reacted with a polyfunctional epoxy compound to form a polyether polyamine, and by using such polyether polyamine, the isocyanate and polyoxyalkylene diamine were reacted in advance. As a result of increasing the reacting primary amine equivalent and relatively decreasing the concentration of functional groups in the reaction system, it was possible to avoid cracking during molding of polyurea elastomer, leading to the completion of the present invention. Furthermore, in the method of using the polyether polyamine of the present invention, since it has an average of two more amino groups per molecule as an incidental effect, it forms a chemical network structure and obtains a polyurea elastomer with high Young's modulus and tensile strength. I can do it. As described above, the greatest feature of the present invention is that it is obtained by the reaction of a specific polyfunctional epoxy compound and polyoxyalkylene diamine. The polyfunctional epoxy compound used as a starting material in the present invention has the formula

[expression] or (In the formula, n is an integer of 2 or more; R is an aliphatic hydrocarbon, an aromatic hydrocarbon, or a heterocyclic compound residue) and has an average molecular weight of 270 to 1000.
Most of these compounds are known compounds and are readily available commercially, and can also be easily synthesized by those skilled in the art using epihalohydrin and the like. For example, the following are used as typical polyfunctional epoxy compounds.

[Table] (n) (-CH ₂ CH ₂ CH ₂ CH ₂ O)- _n CH ₂ CH ₂ CH ₂ CH
₂ − m〓17 2

[Table] Sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether,
pentaerythritol polyglycidyl ether,
Diglycerol polyglycidyl ether, triglycidyl tris(2-hydroxyethyl) isocyanurate, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, tris(2,3-epoxypropyl) isocyanurate, diphenylmethane, 4,4' diglycidyl Amines and the like are conveniently used, and their average molecular weight is preferably about 270 to 1000, taking into consideration the average molecular weight of the target polyether polyamine. In addition, the polyoxyalkylene diamine represented by the formula R′(NH ₂ ) ₂ (wherein R′ is polyoxyalkylene) is obtained by aminating the terminal hydroxyl group of a linear polyoxyalkylene diol with an average molecular weight of 244 to 3004. What is obtained is advantageously used in the present invention. Such compounds are bifunctional compounds obtained by addition-polymerizing one or more alkylene oxides such as ethylene oxide and propylene oxide in any order in the presence of a suitable initiator such as water, a low molecular weight diol, or a low molecular weight amine. It can be obtained by a known method of aminating the terminals of a polyether polyol having a molecular weight of 244 to 3004. Examples of low molecular weight polyols suitable as the above-mentioned initiators include ethylene glycol, propylene glycol, 1,4-butanediol, 1.
6 hexanediol, hydroquinone, 2.2-
Examples include bis(4-hydroxyphenyl)propane, and low molecular weight amines include methylamine, butylamine, and alkanolamines such as ethanolamine, diethanolamine, and triethanolamine. Among the above polyoxyalkylene polyols,
When the terminal hydroxyl group is aminated and used to synthesize the polyether polyol derivative having a terminal amino group of the present invention obtained from this, the molecular weight
244-3004 Divalent polyoxytetramethylene glycol, polyoxypropylene diol, polyoxypropylene polyoxyethylene diol, etc. are suitable. The polyether polyamine of the present invention is produced by a simple single-step synthesis method in which the divalent polyoxyalkylene diamine having a molecular weight of 240 to 3,000 is subjected to an addition reaction with the polyfunctional epoxy resin. The polyether polyamine of the present invention may be one in which all the epoxy groups of the n-valent polyfunctional epoxy resin are reacted with primary amino groups, but some of the epoxy groups may be reacted with primary amino groups. It may be a mixture in which a polyamine in which a secondary amino group and an epoxy group have reacted is present, or it may be a mixture in which an excess amount of polyoxyalkylene diamine is present. The degree of residual unreacted diamine can vary widely depending on the use of the obtained polyoxyalkylene diamine, for example, about 90 to 0.
% of unreacted polyoxyalkylene diamine. Therefore, the polyether polyamine of the present invention can be obtained by reacting preferably n to 10 n moles of polyoxyalkylene diamine with respect to 1 mole of an n-valent epoxy compound. The above-mentioned addition reaction of the present invention is accomplished by carrying out the addition reaction without a catalyst or in the presence of a known addition reaction-promoting catalyst while passing an inert gas such as nitrogen gas and heating to usually room temperature to 160°C. . When using a catalyst, alcohol, water, etc. are suitable. Moreover, an inert solvent can be used in the reaction. The reaction is continued until the characteristic absorption peak based on the epoxy group disappears by infrared absorption spectroscopy or ¹³ C-NMR, and then the pressure is reduced as necessary to completely remove the catalyst alcohol, water, or inert solvent used. Just leave it there. Purification may be performed, but is usually not necessary. The polyether polyamine having at least two terminal amino groups of the present invention can be obtained by the above method. In the present invention, by using such a polyether polyamine in combination with an amine-terminated chain extender and a polyisocyanate and reacting it in a closed mold, it has extremely good mechanical strength, heat resistance, etc., and is free from cracking. A reaction injection molded elastomer that does not generate any reaction can be manufactured with industrial advantage. The chain extender used in this case, polyisocyanate, is disclosed in, for example, JP-A-60-4516 and JP-A-Sho.
Conventionally known materials such as those described in No. 58-188643 can be conveniently used. That is, specific examples of chain extenders useful in the present invention include 1-methyl-3,5-diethyl-
2,4 diaminobenzene, 1-methyl-3,5-
diethyl-2,6-diaminobenzene (both are
Also, diethyltoluene diamine or DETDA), 1,3,5-triethyl-2,6-diaminobenzene, 3,5,3',5'-tetraethyl-4,4'-diaminodiphenylmethane, etc. include.
Particularly preferred aromatic diamine chain extenders include 1-methyl-3,5-diethyl-2,6-diaminobenzene and 1-methyl-3,5-diethyl-2,6-diaminobenzene.
4 diaminobenzene or a mixture of these compounds. U.S. Patent Nos. 4246363 and 4269945
Also included within the ideal scope of this invention are certain aliphatic chain extenders, such as those described in the US Pat. In addition, the polyisocyanate compound used in the present invention contains two or more isocyanate groups in the molecule and has an average molecular weight of 250 to 8,000, and can be any liquid organic polyisocyanate used in the production of normal polyurethane or polyurea, or This is a partially reacted prepolymer of organic polyisocyanate and polyether or polyamine, known as a pseudo-prepolymer. A wide variety of aromatic polyisocyanates may be used in the present invention. Typical aromatic polyisocyanates include p-phenylene diisocyanate, polymethylene polyphenyl isocyanate, 2,6-toluene diisocyanate, dianisidine diisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocyanate, bis(4- isocyanatophenyl)methane, bis(3-methyl-3-isocyanatophenyl)methane, bis(3-methyl-4
-isocyanatophenyl)methane and 4,
4'-diphenylpropane diisocyanate is mentioned. Other aromatic polyisocyanates used in the practice of this invention are methylene-crosslinked polyphenyl polyisocyanate mixtures having a functionality of 2 to 4. These latter isocyanate compounds are generally prepared by reacting formaldehyde with a primary aromatic amine (e.g. aniline) in the presence of hydrochloric acid and/or other acidic catalysts, such as the corresponding methylene-bridged polyphenylpolyamines. Manufactured by Known processes for the production of polyamines and the corresponding methylene-crosslinked polyphenyl polyisocyanates are well known not only in the literature but also in numerous patents (e.g. U.S. Pat.
No. 2683730, No. 2950263, No. 3012008, No.
3344162 and 3362979). Generally, methylene crosslinked polyphenyl polyisocyanate mixtures contain from 20 to 100% by weight of methylene diphenyl diisocyanate isomers (the remainder being polymethylene polyphenyl diisocyanates with higher functionality and higher molecular weight).
These typically contain 20-100% by weight of methylene diphenyl diisocyanate isomers (of which
20-95% by weight is the 4,4'-isomer), with the remainder having a higher molecular weight and an average functionality.
It is a polyphenyl polyisocyanate mixture containing 2.1 to 3.5 polymethylene polyphenyl polyisocyanate. These isocyanate mixtures are known and commercially available materials and are described in U.S. Pat.
Manufactured by the method described in No. 3362979. Particularly preferred aromatic polyisocyanates are methylene bis(4-phenyl isocyanate) in the form of pure MDI, or MDI, pseudo-prepolymers of MDI, modified pure MDI, and the like. These types of materials can be used to make suitable RIM elastomers. Pure
Since MDI is a solid and therefore often inconvenient to use, liquid products based on MDI are often used, which fall within the terminology used in this case: MDI, i.e. methylene bis(4-phenyl isocyanate). included. Examples of liquid MDI products are disclosed in US Pat. No. 3,394,164. More commonly uretonimine modification
MDI is also included in the above definition. This product is produced by heating pure distilled MDI in the presence of a catalyst. The liquid product is a mixture of pure MDI and modified MDI. Commercially available products of this type include Isocyanate 125M and 143L from Appdillon. In the present invention, the above-mentioned amine-terminated polyether (polyether polyamine), amine-terminated chain extender, and polyisocyanate are reacted in a closed mold, preferably in the presence of a catalyst. The polyisocyanate has an NCO equivalent equivalent ratio of 0.9 to the average active hydrogen equivalent of the mixture of the amine-terminated polyether and the amine-terminated chain extender.
-1.3, preferably 1.0-1.1. If a catalyst is used, an organotin compound is preferably used as the organometallic compound. Organotin compounds are stannous and stannous compounds of the following compounds: carboxylic acids, trialkyltin oxides, dialkyltin dihalides,
The organic group of the organic portion of the tin compound, such as dialkyltin oxide, is a hydrocarbon group containing 1 to 8 carbon atoms. For example, dibutyltin dilaurate, dibutyltin disetate, diethyltin diacetate, dihexyltin diacetate, di-2-ethylhexyltin oxide, dioctyltin dioxide, stannous octoate, stannous oleate, etc., or mixtures thereof. used. Other conventional formulation components include silicone oils or foam stabilizers known as emulsifiers. For example, a compound of the following formula is used: RSI[O-( _R2SiO )n-(oxyalkylene)
mR] ₃ (wherein R is an alkyl group containing 1 to 4 carbon atoms, n is an integer of 4 to 8, m is an integer of 20 to 40, and the oxyalkylene group is derived from propylene oxide and ethylene oxide. ). See US Pat. No. 3,194,773. Additionally, known toughening agents may be used if desired. For example, chopped or milled glass fibers, chopped or milled carbon fibers, and/or other mineral fibers may also be used. By the method of the present invention, a reaction injection molded elastomer which has excellent mechanical strength, heat resistance, etc. and is free from cracking can be provided with great industrial advantage. Furthermore, such elastomers are extremely excellent in terms of Young's modulus and tensile modulus. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1 Trimethylpropane polyglycidyl ether
488 g (1.68 mol) and 7000 g (3.36 mol) of polyoxyalkylene diamine were stirred and heated in a three-necked flask while passing dry nitrogen gas, and the temperature was raised to 130 mol.
After about 3 hours of maintaining the temperature at °C, the change in viscosity over time became smaller. After continuing the reaction for an additional hour, heating was stopped and the entire system was cooled to room temperature. The resulting reaction product was a pale yellow liquid with a viscosity of 3600 cps at 25°C. As a result of confirmation of residual epoxy groups by ¹³ C-NMR, no epoxy groups were observed in the reaction product. Also, potentiometric titration (J.Am Chem
Sco. 69, 2609-2614 (1947)), the primary amine equivalent was 2070, and the desired target product was obtained. When this product was analyzed by gel permeation chromatography, no free polyfunctional epoxy compound was detected. Therefore,
This means that all the terminal epoxy groups of EX-321 reacted with the amine active hydrogen groups. Examples 2 to 6 In the same manner as in Example 1, but using the raw materials listed in Table 1 below, polyether polyamines each having the characteristic values listed in Table 1 were obtained. Example 7 Polyether polyamine obtained in Example 1
Millionate as 71.9g and polyisocyanate
MTL was reacted in a closed mold. Tensile strength is 46MPa, elongation rate is 58%, Young's modulus is
The pressure was 1120 MPa, and no cracking occurred within the mold. Examples 8 to 13 and Comparative Example 1 Reaction injection molded plates having the characteristic values shown in Table 2 were obtained in the same manner as in Example 7, but using the raw materials shown in Table 2 below.

【table】

【table】

【table】

Claims (1)

[Claims] 1 formula [expression] or (In the formula, n is an integer of 2 or more, R is an aliphatic or aromatic hydrocarbon, or a heterocyclic compound residue)
A polyfunctional epoxy compound with an average molecular weight of 270 to 1,000 represented by the formula R′(NH ₂ ) ₂ (wherein R′ is polyoxyalkylene) and a polyoxyalkylene diamine with an average molecular weight of 240 to 3,000 are combined with an epoxy group. and amino groups in a molar ratio of 1:2 to 1:6 and reacted to obtain a primary amine equivalent of 200 to 3000 and a viscosity of 200 to 200.
A method for producing a reaction injection molded elastomer, comprising a step of producing a polyether polyamine of 7000 cps, and a step of reacting the polyether polyamine, an amine terminal chain extender, and a polyisocyanate in a closed mold. 2. A reaction injection molded product obtained by the method according to claim 1. 3 formulas [expression] or (In the formula, n is an integer of 2 or more, R is an aliphatic or aromatic hydrocarbon, or a heterocyclic compound residue) A polyfunctional epoxy compound with an average molecular weight of 270 to 1000 and the formula R' (NH ₂ ) A method for producing a polyether polyamine, which comprises reacting a polyoxyalkylene diamine having an average molecular weight of 240 to 3,000, represented by the formula ₂ (wherein R' is polyoxyalkylene).