JPS63135412A - Elastic polyurethaneurea molding - Google Patents

Abstract

PURPOSE:To make possible the formation of moldings which are improved in mold release characteristics, elasticity immediately after the mold release and suppressing voids and excellent in strength and heat resistance, by the reaction-injection molding of a mixture containing a liquid aromatic polyisocyanate, a long-chain molecule polyol, a specified aromatic polyamine as a chain-lengthening agent, a catalyst and other auxiliaries. CONSTITUTION:The title product is an elastic polyurethaneurea molding which is obtained by submitting a mixture containing the following ingredients a-e to a reaction-injection molding in a closed mold. (a) is an aromatic polyisocyanate which is liquid at room temperature, (b) is a long-chain molecule polyol having at least 50% of primary hydroxyl groups, (c) is an aromatic polyamine of formula 1 (where R is a methyl, ethyl, propyl or isopropyl group; X is an R or OR group; n is O or an integer of 1-3; and the molar ratio of R to OR is 5:95-60:40), (d) is a catalyst, and (e) includes a foaming agent, an internal mold release, a filler and other auxiliaries if necessary.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a polyurethane urea elastomer manufactured by reaction injection molding technology, and particularly relates to a polyurethane urea elastomer produced by reaction injection molding technology. It relates to an elastic molded article with a dense surface manufactured by reaction injection molding technology.

Polyurethane elastic molded products, which have a dense surface and excellent physical properties, moldability, and appearance, are widely used. Specific examples of reactions include a wide range of products such as automobile plate materials, sports and leisure goods, office equipment housings, furniture, and agricultural equipment. Among these, the most used are automobile bumpers, fascias, fenders, doors, side moldings and their R4Q parts. The present invention aims to provide a material that has such a very wide field of application and is of higher value in terms of performance and economy.

(Prior Art) It is known to mold non-foamed polyurethanes, their fiber-reinforced elastomers or microcellular polyurethane elastomers by reaction injection molding by polyaddition of isocyanates and isocyanate-reactive compounds. The raw materials for these polyurethanes are usually polyisocyanates, polyether polyols and polyester polyols with hydroxyl groups, chain extenders, catalysts and optionally blowing agents, auxiliaries, additives and fibrous inorganic compounds, reaction injection molding. Law is Reaction Injection
Molding (hereinafter referred to as RI?+) is a process in which isocyanate and an isocyanate-reactive component mixture are brought into a mixing injection machine and collided with each other under pressure (often under high pressure), and this mixture is filled into a mold and cured. This is a method for taking out molded products.

Among these raw materials used, the chain extender has a particularly significant influence on moldability and physical properties.Ethylene glycol or 1,4-butanediol has traditionally been used as the chain extender. However, neither of them necessarily provided sufficient performance in terms of moldability and physical properties.Specifically, for example, curing properties, void generation rate, mold releasability, heat resistance, tensile properties, etc. were not sufficient.

(Problem to be solved by the invention) Various improvements have been attempted to address these problems.

For example, in JP-A-56-109216, a relatively large amount of an aliphatic amine extender is used in combination with ethylene glycol to improve mechanical strength and heat resistance. However, since this method uses ethylene glycol as the main chain extender, significant improvements in mechanical strength and heat resistance cannot be achieved. Furthermore, the aliphatic amines that are most frequently used in the patent and have a relatively large molecular weight, which is defined as ``suitable'' and 1, do not themselves significantly improve curing properties and heat resistance.

Another method is, for example, as disclosed in JP-A-52-77200, in which a small amount of a polynuclear mixed polyamine synthesized as an aromatic polyamine by condensation of aniline and formalin is used in combination with ethylene glycol to improve heat resistance.

Aromatic polyamines have a very large effect on improving heat resistance. However, with this method, the high reactivity of the aromatic polyamine used reduces the ability to fill the mold during reaction injection molding, making it impossible to obtain a satisfactory molded product, which limits the amount used. . Furthermore, since alkanediol is used, a significant improvement in heat resistance cannot be expected.

Another method is to use halogen-containing diaminobenzene as a chain extender to improve heat resistance, as disclosed in JP-A-58-32626. In the second method, the reactivity of halogen-containing diaminobenzene is moderately fast, but
On the other hand, curing is slow and problems remain in molding.

As we have seen above, chain extenders greatly affect the performance of polymers, but most of them are not satisfactory in terms of physical properties and moldability. Furthermore, even with aromatic diamines that have satisfactory physical properties, the reaction is too fast, resulting in problems such as the need for a large injection molding machine (Means for Solving the Problems) The present inventors have In order to improve the curing properties, mold release properties, and heat resistance, which are the shortcomings of conventional urethane RIM using glycol curing, we issued a patent for using an aromatic polyamine obtained by condensing orthoanisidine and formalin as a chain extender.
1 (Japanese Patent Application No. 6O-248987).

Although the second aromatic polyamine is extremely effective as a countermeasure for the above-mentioned problems, it is necessary to improve the reactivity which is too high and the poor compatibility with long chain molecular polyols due to the high melting point. As a result of further intensive studies to improve this point, it was discovered that it is effective to add orthoalkylaniline when condensing orthoalkoxyaniline and formaldehyde, and the present invention was achieved.

That is, the present invention comprises (a) an aromatic polyisocyanate that is liquid at room temperature; (b)
The molecular weight is from 1000 to 12000, and at least 50
% or more of primary hydroxyl polyol (c) General formula [where R is a methyl group, ethyl group, propyl group or isopropyl group, X is an R or OR group, n is O or 1 to 3
represents an integer, and the molar ratio of R and OR is 5:95 to 60
: 40. ] A mixture containing an aromatic polyamine represented by (d) a catalyst, and optionally (e) a blowing agent, an internal mold release agent, a filler and other auxiliary agents is reaction injection molded in a closed mold. In the present invention, which is an elastic polyurethaneurea molded product, by mixing orthoalkylaniline with orthoalkoxyaniline, the crystallinity and melting point of the aromatic polyamine obtained by condensation with formaldehyde are lowered. the result,
Compatibility with long-chain molecular polyols is improved.

The aromatic polyamine used as component (c) in the present invention is produced by condensing orthoalkylaniline and orthoalkoxyaniline with formaldehyde.

Orthoalkylanilines are specifically orthotoluidine, orthoethylaniline, orthopropylaniline, and orthoisopropylaniline.

Specific examples of orthoalkoxyaniline include orthoanisidine, orthophenetidine, orthoalkylaniline, and orthoisopropoxyaniline, of which orthoanisidine is particularly preferred.

The molar ratio of orthoalkylaniline to orthoalkoxyaniline is preferably from 5:95 to 60:40, and particularly preferably from 10:90 to 50:50. The aromatic polyamine produced under these conditions contains 4
゜4°-di,amino-3-alkyl-3°-alkoxydiphenylmethane is present in the largest amount, and 4゜4
Contains '-diamino-3,3'-dialkoxydiphenylmethane and 4,4'-diamino-3,3'-dialkyldiphenylmethane.If the molar ratio of orthoalkoxyaniline is out of this range, compatibility will decrease. Smooth progress of the reaction is inhibited.

Aromatic polyamine can be represented by the following general formula.

In this formula, R represents a methyl group, ethyl group, propyl group or isopropyl group, X represents R or an OR group, and n represents O or an integer of 1 to 3.

The above amine preferably has a dinuclear (n=o):trinuclear or more (n=1 to 3) ratio of 90:10 to 40:60.
(wtX). This is because if there are many polynuclear bodies, the reactivity of some of the amino groups will decrease too much.

The aromatic polyamine of component (c) can be obtained, for example, by reacting orthoalkoxyaniline and orthoalkylaniline in an aqueous formalin hydrochloric acid solution, followed by rearrangement at high temperature and neutralization with alkali.

The aromatic polyamine is used in an amount of 10 to 70 parts by weight per 100 parts by weight of the long-chain molecular polyol.

Examples of the aromatic polyisocyanate used as component (a) in the present invention include 4,4°-diphenylmethane diisocyanate, 2,4- and
These include dolylene diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, dimers, trimers, carbodiimide modified products, allophanate modified products, biuret modified products, prepolymers, etc. of these isocyanates.

Among these aromatic polyisocyanates, a particularly preferred isocyanate compound for the present invention is the tam form of 4,4'-diphenylmethane diisocyanate, which is liquid at room temperature. Specific examples of this compound include: Urethane groups obtained by reacting 4,4'-diphenylmethane diisocyanate with low molecular weight diols or 1-liols (preferably polypropylene glycols having a molecular weight of less than 700). Containing polyisocyanate: 4,4°-diphenylmethane diisocyanate-based diisocyanate containing a carbodiimide group and/or urethane imine group, and examples of preferred polyisocyanates include the following: 2.4
A modified product prepared by modifying a mixture of '- and 484'-diphenylmethane diisocyanates as described above: 4,4'-diphenylmethane diisocyanate modified as described above and a small amount of diphenylmethane-based functionality higher than the difunctionality. mixture with polyisocyanate having a degree of

Examples of long chain molecular polyols used in the present invention include:
Ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1
, 3.6-hexanetriol, pentaerythritol, polyhydric alcohols such as sorbitol, and/or hydroxyl value 20 to 800 mg K obtained by addition polymerizing alkylene oxide to these polyhydroxy compounds.
OH/g polyether polyol. In addition, alkanolamines such as jetanolamine and triethanolamine, amines containing two or more active hydrogens such as ethylene diamine, diethylene triamine, ammonia, aniline, tolylene diamine, xylylene diamine, and diaminodiphenylmethane, ethylene oxide, propylene Hydroxyl value 20~ obtained by addition polymerization of oxide, butylene oxide, styrene oxide, etc.
800 mg K OH/g of polyether polyol and polytetramethylene ether glycol can also be used.

In addition to the above, there are also higher fatty acid ester polyols, polyester polyols obtained by reacting polycarboxylic acids with low molecular weight polyols, polyester polyols obtained by polymerizing caprolactone, and higher fatty acid esters containing OH groups such as castor oil and dehydrated castor oil. Can be used.

In addition, polymer polyols obtained by grafting an ethylenically unsolarized compound such as styrene, acrylonitrile, and methyl methacrylate onto the above-mentioned known polyether polyols or polyester polyols, and 1,2- or 1,4-polybutadiene polyols, or these. Hydrogenates can also be used. These polyols may be used alone or in combination of two or more.

When carrying out the present invention, the amount of each raw material used is such that the equivalent ratio of the NGO group contained in the aromatic polyisocyanate to the active hydrogen contained in the polyol and aromatic polyamine is 0.8 to 1.3. Adjust.

Catalysts used as component (d) in the present invention include organometallic catalysts such as dibutyl diacetate, dibutyltin dilaurate, tin oleate, tin octoate, triethylamine, N, N, N', N' tetramethyl -propanediamine, 1,4-diazabituruclo (2,2,
2) There are amine catalysts such as -octane and pentamethyldiethylenetriamine.

As a blowing agent, trichlorofluoromethane, CCLzF
, CGl□F2, methylene chloride, water, nitrogen gas, carbon dioxide gas, etc.

There are various types of internal mold release agents, such as silicone-based ones, fatty acid metal salts, fatty acid amide derivatives, and fatty acid ester diluent black bodies.

Fillers include glass fiber, flake glass, mica,
Other auxiliary agents include talc, inorganic compound whiskers, etc., pigments such as carbon, antioxidants, weathering stabilizers, etc.

(Function) In the present invention, the melting point of the aromatic polyamine decreases, the compatibility with the polyol increases, and the reaction rate decreases.

(Example) A mixed stock solution was prepared using the above raw materials, and R[M molding was performed in a mold using an injection molding machine for polyurethane.

Synthesis examples and examples of aromatic polyamines will be described below.

Synthesis Example 1 42.8 g of 〇-toluidine (0,
4 mol), 0-anisidine 197 g (1.6 mol)
, 197.8 g (1.3 mol) of 24% hydrochloric acid were added and mixed, and then 111 g (1.0 mol) of 37% formalin was added dropwise at 30° C. or below over a period of 1 hour. After the dropwise addition was completed, stirring was continued for another 30 minutes at the same temperature, and then the temperature was raised to 100°C over 1 hour and maintained at 100°C for 1 hour.

After the reaction, 116 g (1.3 mol) of 45% aqueous sodium hydroxide solution was added and stirred at 80° C. for 30 minutes. The precipitated oil is separated and washed three times with warm water at 80°C. This is 80
Dehydration was performed at °C to obtain 256 g of methylene-crosslinked aromatic polyamine. The yield is 94.8%. The product was a brown solid with a melting point of 70 to 90°C, a dinuclear content of 83.3%, a polynuclear content of 16.7%, and a methyl group content of 2 Jwt%.

This was designated as aromatic polyamine-1.

Synthesis Example 2 64.2 g of 0-toluidine (0,
6 mol), 0-anisidine 172 g (1.4 mol)
, 197.8 g (1.3 mol) of 24% hydrochloric acid were added and mixed, and then 111 g (1.0 mol) of 37% formalin was added dropwise at 30° C. or below over a period of 1 hour. After the dropwise addition was completed, stirring was continued for another 30 minutes at the same temperature, and then the temperature was raised to 100°C over 1 hour and maintained at 100°C for 1 hour.

After the reaction, 116 g (L3 moles) of 45% aqueous sodium hydroxide solution was added, and the mixture was stirred at 80° C. for 30 minutes. The precipitated oil is separated and washed three times with warm water at 80°C. This is 80℃
After dehydration, 251 g of methylene-crosslinked aromatic polyamine was obtained. The yield is 95.2%. The product is a brown solid with a melting point of 7.
0 to 90°C, dinuclear content 81.0%, polynuclear content 1
9.0%, and the methyl group content was 3.4%. This was designated as aromatic polyamine-2.

Polyol A: Polyoxyalkylene diol with a hydroxyl value of 28 mgK OH/g and a primary hydroxyl group content of 80%, obtained by addition polymerizing ethylene oxide and propylene oxide to propylene glycol.

Polyol B: A polyoxyalkylene triol having a hydroxyl value of 28 mgKOH/g and a primary hydroxyl group content of 75%, obtained by addition polymerizing ethylene oxide and propylene oxide to glycerin.

Isocyanate A...N obtained by reacting diphenylmethane diisocyanate and tripropylene glycol
Prepolymer Isocyanate B with a CO group content of 22%: A prepolymer with an NCO5 content of 26% obtained by reacting a mixture of diphenylmethane diisocyanate and its carbodiimide modified product with tripropylene glycol.

Examples 1 to 3 Polyol A and polyol B2 in the amounts shown in Table 1, aromatic polyamine-1 or -2, and dibutyltin dilauret (DBTDL) as a catalyst were mixed to prepare a resin liquid. Isocyanate A or Isocyanate B
I reacted.

The reaction injection molding machine is LRM- manufactured by Cincinnati Milacron.
L15 type was used. The mold is 900x 600x 2.
A 5twin sheet mold was heated to 75°C.

The temperature of the stock solution was adjusted to 30° C., and the flow rate ratio of the resin solution to the isocyanate component was adjusted as shown in Table 1. Dry nitrogen gas was mixed and dispersed in the resin liquid in an amount of 15% by volume, and the mixture was injected into the mold at an injection speed of 1000 g/see and an injection time of 2 seconds.

The molds were demolded 40 seconds after injection, and the quality of the mold releasability and the elasticity immediately after demolding were compared. Immediately after demolding, the molded product was bent 180 degrees and the time required for no cracking to occur was measured to determine the green strength. The surface condition of the molded product and the presence or absence of voids were also examined. Furthermore, test pieces were cut from the molded products and their tensile strength, elongation, notched Izont impact value, bending modulus, and heat resistance were measured. For the heat resistance test, a 2 x 150 m strip-shaped specimen was fixed horizontally at a position of 50 m from one end.
Leave it in a constant temperature bath at 20°C for 1 hour. After leaving it alone, the other end drooped! ! ! l (thermal sag) was measured and the heat resistance was compared. The results were as shown in Table 2.

Comparative Example 1 The same treatment as in Example was carried out except that ethylene glycol was used instead of the aromatic polyamine of the present invention, and the stock solution formulation was as shown in Table 1, and the obtained results were as shown in Table 2. became.

Comparative Example 2 A sample was treated in the same manner as in Example except that diethyltoluenediamine (DETDA) was used instead of the aromatic polyamine of the present invention. The formulations were as shown in Table 1, and the results obtained were as shown in Table 2.

(Effects) As is clear from Tables 1 and 2, as a result of adjusting the reaction rate according to the present invention, the filling property into the mold is improved, the mold releasability, the elasticity immediately after demolding, the voids are improved, and the strength is improved. , Amendment to Table 1, Table 2 procedure for obtaining a molded product with excellent heat resistance, etc. (voluntary) 2nd/7th, 1988

Claims (1)

[Claims] (a) an aromatic polyisocyanate that is liquid at room temperature; (b)
The molecular weight is from 1000 to 12000, and at least 50
% or more of primary hydroxyl groups (c) General formula ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ [However, R is a methyl group, ethyl group, propyl group, or isopropyl group, and X is R or OR group, n is 0 or 1-3
represents an integer, and the molar ratio of R and OR is 5:95 to 60:
It is 40. ] An elastic product obtained by reaction injection molding a mixture containing an aromatic polyamine represented by (d) a catalyst, and optionally (e) a blowing agent, an internal mold release agent, a filler, and other auxiliaries in a closed mold. Polyurethane urea molded product.