JPH0464602B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for molding a heat-resistant polyisocyanurate resin, and more specifically, a method for molding a heat-resistant polyisocyanurate resin using two-component reaction injection or an injection molding machine to obtain a molded polyisocyanurate resin with excellent heat resistance. Concerning a molding method. The present invention also relates to a method for efficiently molding a polyisocyanurate resin having excellent heat resistance using a two-component reaction injection or injection molding machine. Generally, polyisocyanurate resins obtained from organic polyisocyanates have good hardness,
It is fire resistant and can also be used at relatively high temperatures, e.g.
It is known to have mechanical resistance even at 180°C. On the other hand, compounds having ethylenically unsaturated bonds tend to polymerize simultaneously when the polyisocyanate trimerizes, and their polymerization is promoted by heating. Polyisocyanate and a compound containing ethylenically unsaturated bonds are copolymerized in the presence of a trimerization catalyst to form interpenetrating polymer networks (IPN).
to form mechanical properties, electrical properties, or
It is very important as an industrial material because it can be designed to have properties not found in polyisocyanurate homopolymers, such as chemical resistance. However, with conventional techniques, when such IPN is reaction-molded, it is difficult to obtain a perfect molded product because it tends to collapse when demolded. In addition, these materials do not have sufficient thermal stability at temperatures above 200°C, and begin to soften, deform, and decompose at these temperatures, causing cracking and foaming, and when exposed to flame in this state, they ignite and burn. As a result, the heat resistance and flame resistance were generally inferior. On the other hand, in order to efficiently mold the above-mentioned IPN using a two-component reaction injection or injection molding machine, the resin injected or injected into the mold immediately starts a polymerization reaction, and the polymerization reaction occurs inside the mold. It is important that the polymerization reaction proceed as quickly as possible and that the degree of completion of the polymerization reaction is as high as possible. By satisfying these conditions, the molding cycle is increased, and at the same time, the strength of the cured resin at the time of demolding is increased, and even complex molded products can be easily demolded. Furthermore, if the demolded molded product does not undergo cracking, softening deformation, or foaming during post-curing, and the IPN reaction progresses reliably during post-curing,
It is expected that a polyisocyanurate resin with high heat distortion temperature and excellent heat resistance will be obtained. In conventional polymerization reaction and molding processing techniques, there is an induction period before the polymerization reaction, the polymerization reaction rate during and after injection or injection is low, and
The molded product is brittle due to insufficient completion of the polymerization reaction.
Since it is easy to break during demolding, it has been difficult to obtain molded products with complex shapes. In addition, molded products can be heated to 110℃.
If heated above this temperature, cracking, softening deformation, or foaming will occur, so it is impossible to further advance the IPN reaction by post-curing, and as a result, the molded product is brittle and has poor heat resistance. It has little industrial value, and under the current circumstances, its range of applications is extremely limited. The present invention was made to solve the above problems, and has the following objects. (1) Providing a method for obtaining a polyisocyanurate resin molded product with extremely excellent heat resistance, which is made of polyisocyanate and IPN, an ethylenically unsaturated bond-containing compound; (2) Using a two-component reaction injection or injection molding machine. To provide a method for efficiently manufacturing polyisocyanurate resin molded products with excellent heat resistance; (3) to expand the field of industrial use of polyisocyanurate resin molded products. The present invention aims to achieve the above objects. This was achieved as a result of intensive research. That is, the present invention uses a liquid mixture of an organic polyisocyanate and/or an isocyanate group-containing prepolymer and an epoxy compound as the first component, and an ethylenic inorganic compound as the second component when molding with a two-component reaction injection or injection molding machine. Molding of a polyisocyanurate-based heat-resistant resin characterized in that after injection molding or injection molding using a liquid mixture of a saturated bond-containing compound, an aziridine compound, and a tertiary amine, the post-curing start temperature is set at 110 to 170°C. It is about the method. 2 that can be used to carry out the present invention
What is Component Reaction Injection or Injection Molding Machine?RIM
(Reaction Injection Molding) or LIM
(Liquid Injection Molding) is a type of molding equipment that introduces two types of component liquids simultaneously under pressure into a mixing chamber, mixes them, injects them into a closed mold, and reacts and cures them in the mold to obtain a molded product. It is. Also,
Equipment and molding equipment systems, such as two-component urethane foaming machines and other two-component compounding machines, that mix two types of liquids through a mixing chamber under normal or pressurized pressure and then discharge and inject them into an open mold under normal pressure. etc. can also be used. Of these, especially for efficient molding.
RIM devices are preferred. Examples of organic polyisocyanates that can be used in the present invention include aliphatic, cycloaliphatic, aromatic-substituted aliphatic, aromatic, or heterocyclic polyisocyanates, such as hexamethylene-1,6-
diisocyanate, 2,2,4- or 2,2,
6-trimethylhexamethylene-1,6-diisocyanate, 1-isocyanato, 3,3,5-trimethyl-5-isocyanatomethylcyclohexane, cis- or trans-cyclohexane-1,4
-Diisocyanate, dicyclohexylmethane-
4,4'-diisocyanate-ω,ω'-diisocyanatocyclohexane, isopropylidene dicyclohexyl-1,4-diisocyanate, tolylene-2,4- or -2,6-diisocyanate,
diphenylmethane-2,4'- or -4,4'-diisocyanate, naphthylene-1,5-diisocyanate, bitolylene diisocyanate, dianisidine diisocyanate, m- or p-phenylene diisocyanate, xylylene-1,3- or - Diisocyanates such as 1,4-diisocyanate, 4-isocyanatolumethyloctamethylene-1,8-diisocyanate, triphenylmethane-4,4′,4”-triisocyanate,
Tri- or higher functional polyisocyanates such as tris(4-isocyanatophenyl)thiophosphate, undecane-1,6,10-triisocyanate, diphenylmethane-3,3',4,4'-tetraisocyanate, and aniline are combined with formalin. Polyphenylpolymethylene polyisocyanates obtained by condensing polyfunctional amines and phosgenating them, and diphenylpolymethylene polyisocyanates that are liquid at room temperature and have carbodiimide or uretonimine groups as described in Japanese Patent Publication No. 38-4576. Examples include enylmethane diisocyanates, and the above-mentioned modified polyisocyanates containing urethane bonds, allophanate bonds, urea bonds, biuret bonds, oxazolidone bonds, isocyanurate ring structures, and uretidinedione ring structures. These organic polyisocyanates can be used alone or as a mixture of two or more. Among the above polyisocyanates, it is industrially easily available and has a low vapor pressure.
Particularly suitable are diphenylmethane diisocyanate-based liquid polyisocyanates, which have advantages in handling such as being liquid at room temperature. The isocyanate group-containing prepolymer that can be used in the present invention is one obtained by reacting an active hydrogen compound with an excess of organic polyisocyanate, such as ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, low molecular weight diols such as diethylene glycol, dipropylene glycol,
Low molecular weight trifunctional or higher functional polyols such as glycerin, trimethylolpropane and pentaerythritol, hydroxyl group-terminated polyethers obtained from alkylene oxide and low molecular weight polyols, hydroxyl group terminated from lactones and low molecular weight polyols. Polyesters, hydroxyl group-terminated polyesters obtained from polybasic acids such as adipic acid, phthalic acid, tricarballylic acid and low molecular weight polyols, and other hydroxyl group-containing oligomers used in the polyurethane industry, such as polycarbonate polyols, It is made by reacting one or more kinds of polyols with a relatively high molecular weight (molecular weight of about 500 to 8,000) such as polybutadiene polyol, polyolefin polyol, and castor oil polyol with an excess of organic polyisocyanate. be. The organic polyisocyanate or isocyanate group-containing prepolymer can be used alone or as a mixture in any mixing ratio. The isocyanate group content of these individual products or mixed products is:
It is preferably about 4 to 35% by weight. More preferred isocyanate group content is 10 to 30% by weight, particularly preferred is 15 to 25% by weight. When the isocyanurate group content is less than 4% by weight, there is too little isocyanurate ring structure introduced into the cured product, resulting in poor heat resistance, and when the isocyanate group content exceeds 35% by weight, The theoretical polyisocyanurate network density of the cured product becomes extremely large, and the network formation reaction cannot be completed sufficiently due to the effects of steric hindrance, making the cured product brittle and causing foaming and cracking when heated. . Epoxy compounds which can be used in the present invention are, for example, mono- or polyepoxy compounds such as allyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, p-butylphenyl glycidyl ether, butylene oxide, propylene oxide, octylene oxide,
Monoepoxy compounds such as styrene oxide, glycidol, glycidyl ether of versatile acid, diglycidyl ether of pisphenol A, butadiene diepoxide, 3,4-epoxycyclohexylmethyl (3,4-epoxy)-cyclohexanecarboxylate, bicyclohexene Dioxide, 4,4'-di(1,2-epoxyethyl) diphenyl ether, 4,4'-di(1,2
-epoxyethyl)biphenyl, 2,2-bis(3,4-epoxycyclohexyl)propane,
diglycidyl ether of resorcin, bis(2,
3-epoxycyclopentyl)ether, 2(3,
4-epoxy)cyclohexane-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, bis-(3,4-epoxy-6-methylcyclohexyl)azibate, N,N'-m-phenylenebis(4 , 5-epoxy 1,2-cyclohexanedicarboximide and other diepoxides,
Triglycidyl ether of para-aminophenol, polyallyl glycidyl ether, 1,3,5
--(1,2-epoxyethyl)benzene-2,
2',4,4'-tetraglycidoxybenzophenone, tetraglycidoxytetraphenylethane,
Epoxy compounds having trifunctionality or more are used, such as polyglycidyl ether of phenol formaldehyde novolak, triglycidyl ether of glycerin, and triglycidyl ether of trimethylolpropane. The above epoxy compounds may be used alone or as a mixture of two or more. Among these epoxy compounds, liquid monoepoxides with low vapor pressure are particularly preferred in terms of handling. The epoxy compound is used as a subsidiary component for the organic polyisocyanate, and the weight fraction of the epoxy compound is 0.1 to 30% by weight based on the total amount of the organic polyisocyanate and/or isocyanate group-terminated prepolymer and the epoxy compound. Particularly suitable is 0.5
~10% by weight. If the content of the epoxy compound is less than 0.1% by weight, the degree of reaction completion in the latter half of the polyisocyanurate formation reaction is insufficient, and demolding becomes difficult during molding with a two-component reaction injection or injection molding machine. Furthermore, if the content of the epoxy compound exceeds 30% by weight, the heat distortion temperature of the cured resin decreases, and the heat resistance accordingly decreases. The mixture of organic polyisocyanate and epoxy compound is preferably a liquid with low viscosity at room temperature, but mixtures that can be made liquid with low viscosity by heating or contain solid dispersions may also be used as the first component in a two-component reaction injection or injection molding machine. Any liquid may be used as long as it does not impair flowability, meterability, mixability, or injection or injection properties. However, for the sake of mixability, injection/injection properties, or simplification of the structure of the molding machine, it is particularly preferable that these mixtures be liquid at room temperature and have a viscosity of 50 boids or less. Ethylenically unsaturated bond-containing compounds that can be used in the present invention include (a) the following formula: (However, R ₁ is a hydrogen atom, an alkyl group with 1 to 5 carbon atoms, or a cycloalkyl group with 5 to 8 carbon atoms, and Z is the residue of an n-functional monoalcohol or polyol excluding the hydroxyl group. , n is 1 to 4
is the number of ), such as methyl acrylate,
Acrylic acid alkyl esters such as ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, tertiary butyl acrylate, amyl acrylate, hexyl acrylate, lauryl acrylate, stearyl acrylate, and these Acrylic acid cycloalkyl esters such as methacrylic acid alkyl esters, acrylic acid cyclohexyl esters, acrylic acid cycloalkyl esters such as cyclooctyl acrylates, and acrylic acid cycloalkyl esters corresponding to these methacrylic acid cycloalkyl esters, methoxyethyl acrylates, ethoxyethyl acrylates, etc. Esters and their corresponding alkoxyalkyl esters of methacrylic acid, ethylene glycol diacrylate, diethylene glycol diacrylate 1,4
-Butasidiol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol dimethacrylate, polypropylene glycol (molecular weight 200-2000) diacrylate, polyethylene glycol (molecular weight 200-2000) diacrylate triacrylate Acrylic esters of polyols such as methylolpropane triacrylate and corresponding methacrylic esters, or (b) the following formula (However, Y is the residue of m-functional carboxylic acid excluding the carboxyl group, and m is a number from 1 to 4.)
Allyl ester monomers represented by, for example, allyl benzoate, diallyl adibate,
diallyl phthalate, diallyl isophthalate,
diallyl chlorendate, triallyl trimellitate, tetraallyl pyromellitate, etc., or oligoesters from c(c) α,β-unsaturated dicarboxylic acids, such as maleic anhydride, fumaric acid, citraconic acid, (d) other ethylenically unsaturated bond-containing compounds;
For example, vinyl acetate, styrene, vinyltoluene, α-methylstyrene, divinylbenzene,
Triallyl cyanurate, diallylbenzene phosphonate, pentaerythritol diallyl ether, N-vinylpyrrolidone, maleimide, and the like can be used. These can be used singly or as a mixture of two or more, but those that are liquid, have low viscosity, and are easily copolymerized during trimerization of polyisocyanate are preferred; , 4-butanediol diacrylate, 1,6-hexanediol diacrylate, neobentyl glycol diacrylate, tetraethylene glycol dimethacrylate, diallyl phthalate, and the like are particularly preferred. The aziridine compound that can be used in the present invention is represented by (a) the following formula: (However, R ₂ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R ₃ is a hydrogen atom or a hydroxyl group, X is a hydrogen atom or an l-functional residue, and l is a
~6 numbers. ), for example,
2-(1-aziridinyl)ethyl methacrylate,
2-(1-aziridinyl)ethyl methacrylate,
2-(1-aziridinyl)ethyl acrylate,
ω-Methyl aziridinylpropionate, ethylene glycol bis(ω-aziridinylpropionate), trimethylolpropane tris(ω
-aziridinylpropionate), pentaerythritol tetra (ω-aziridinylpropionate), sorbitol hexa (ω-aziridinylpropionate), β-(2-methylaziridinyl)ethyl methacrylate, diethylene glycol Bis[ω-(2-methylaziridinyl)propionic acid ester], 1,3,6-
Aziridine compounds 1-(2-
hydroxyethyl)aziridine, 1-(2-hydroxyethyl)-2-methylaziridine, 1-(2
-hydroxyethyl)-2ethylaziridine, 1
-Aziridine compounds containing hydroxyl groups such as -(2-hydroxy-2-phenylethyl)aziridine, 1-(2-hydroxy-2-phenylethyl)-2-methylaziridine, 1-(2-cyanoethyl)aziridine, 1- Aziridine compounds containing a nitrile group such as (2-cyanoethyl)-2-methylaziridine, 1-(2-cyanoethyl)-2-ethylaziridine, ω-aziridinylpropionic acid, ω-(2-methylaziridine) )
Aziridinyl compounds containing a carboxyl group such as propionic acid, aziridine compounds containing an amide group such as ω-aziridinylpropionic acid amide, ω-(2-ethylaziridinyl)propionic acid amide, 1-(β -Aziridine compounds containing an ether bond such as -methoxyethyl)aziridine, 1-(β-methoxyethyl)-2-ethylaziridine, 1-ethylaziridine, 1-(β-phenylethyl)-2-methylaziridine, etc. compound, or (b) the following formula (However, R ₄ is a hydrogen atom or a lower alkyl group)
Examples of the triethylene melamine derivatives include triethylene melamine, tris (2-methylethylene) melamine, and tris (2-ethyl ethylene melamine). The above aziridine compounds can be used alone or as a mixture of two or more. Tertiary amines that can be used in the present invention include:
For example, aliphatic, alicyclic, aromatic substituted aliphatic, heterocyclic tertiary amines, such as triethylamine, tri-n-propylamine, tri-isopropylamine, tri-n-butylamine, tri- Isobutylamine, tri-tert-butylamine, triamylamine, trihexylamine, trihebutylamine, trioctylamine, trinonylamine, tridecylamine, triundecylamine, tridodecylamine, triotadecylamine, tetramethylethylenediamine, venta Methyldiethylenetriamine, hexamethyltriethylenetetramine, tetramethylbutanediamine, tetramethylhexanediamine, bis(N,
Aliphatic tertiary amines such as N-diethylaminoethyl) adipate, dimethylaminopropylamine, bis(N,N-dimethylaminoethyl)ether, N,N-dimethylcyclohexylamine,
Alicyclic tertiary amines such as N-methyldicyclohexylamine, tribenzylamine, 2,4,6
- Aromatic substituted aliphatic tertiary amines such as tris(dimethylaminomethyl)phenol, N-methylmorpholine, N-ethylmorpholine, N-dodecylmorpholine, N,N'-dimethylpiperazine,
1,8-diazabicyclo[5,4,0]undecene-7,N,N',N''-tris(dialkylaminoalkyl)hexahydrohydro-s-triazine, 1,4-diazabicyclo[2,2,2] Heterocyclic tertiary amines such as octane, 2-methyl-1,4-diazabicyclo[2,2,2,]octane, etc. One type or two or more types of these can be used. In the method for molding a polyisocyanurate-based heat-resistant resin of the invention, an epoxy compound blended into the first component system in order to simultaneously progress the conversion of polyisocyanate to polyisocyanurate and the polymerization of the ethylenically unsaturated bond-containing compound. The aziridine compound and tertiary amine added to the second component system each play an important role. (1) Aziridine compound: eliminates the induction period for IPN formation and enables simultaneous polymerization. , 0.1 for the total amount of the first and second components
~20% by weight, preferably 0.5-10% by weight. (2) Tertiary amine: Enables polymerization of polyisocyanate and a compound containing an ethylenically unsaturated bond. For this reason, 0.1 to 10% by weight, preferably 0.2% by weight, based on the total amount of the first component and the second component.
~5% by weight. (3) Epoxy compound: promotes the polymerization of polyisocyanate and compounds containing ethylenically unsaturated bonds,
Enables rapid curing. For this reason, the first
It is present in an amount of 0.1 to 20% by weight, preferably 1 to 10% by weight, based on the total amount of the component and the second component. In addition, in the present invention, the liquid ratio of the first component to the second component is approximately 1:1 to 5:1 by weight of the latter to the former, but one or both of the above components may contain pigments, foaming In this case, the above-mentioned compounding ratio is changed based on the additives, filling reinforcing agents, surfactants, stabilizers, or other compounding materials. Liquid reaction molding uses the above two-component system, and measures and mixes it with a two-component low-pressure blender or a two-component high-pressure blender,
This is carried out by pouring a predetermined amount into a mold with an open end treated with a release agent, or by injecting it into a closed mold through a runner. The molded product cured in the mold is removed from the mold or cured afterwards. Post-curing is performed at an appropriate temperature of 110 to 170° C. for a necessary period of time, and thereafter, if necessary, appropriate post-curing is performed within or outside this temperature. The initial post-cure time is 3-8 hours. According to the present invention, large, thin-walled molded products with complex shapes can be efficiently produced, and the molded products have excellent heat resistance, so they can become extremely useful industrial materials. These uses include, for example, television,
Main shells of VTRs or audio equipment, electrical equipment parts such as switch covers, printed circuit boards, lamp covers, household items such as frying pan handles, iron handles, oven plates, engine room bulkheads, engine-related parts, It is extremely important and useful in automotive parts such as lamp covers and structural members around heaters, and industrial materials such as solar thermal equipment and structural members for nuclear reactors. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to these examples. Examples 1 to 8, Comparative Examples 1 to 5 The first and second components shown in Table 1 were filled into each tank of Twin Flow VR (manufactured by Naka Seiki, normal pressure two-component blender), and heated at 25°C. After controlling the temperature, the liquid was pumped using a gear pump to achieve a predetermined mixing ratio, and the mixed liquid was mixed using a mechanical stirring device with a pin type rotor. was injected (open). After the resin in the mold had hardened, it was removed from the mold, and the molded product was cured for a predetermined period in a gear oven, and then its physical properties were measured. Table 1 shows the evaluation results of the molded products according to the present invention (Nos. 1 to 8) and the molded products of comparative examples (Nos. 1 to 5). Note that the first component and the second component were degassed for 1 hour under 10 Torr prior to injection molding.

【table】

【table】

[Table] In Table 1, the formulations are shown in parts by weight.
In addition, each measurement value is as follows. (1) Density (g/cm ³ ): Calculated from the dimensions and weight of the test piece. (2) Percoll hardness: GYZJ934− according to JISK6911
One type was measured. (3) Tensile strength (Kg/cm ³ ) and tensile modulus (Kg/cm 3 )
cm ³ ): Measured according to JISK7113. (4) Heat distortion temperature (℃): According to JISK7207, load
Measured under 18.6Kg/ ^cm3 . (5) Izotsu impact strength (Kg・cm/cm):
Measured according to JISK7110. Example 9 First component and second component shown below

【table】

Fill each tank of the TK-10RIM machine (polyurethane engineering two-component reaction injection molding machine) with [Table], adjust the temperature of each liquid to 30℃, and measure the liquid ratio of the first component/second component using a piston cylinder. were set to have a weight ratio of 121/33, and these were mixed using an impingement stirring method, and a fluororesin-based mold release agent was applied in advance, and the mixture was injected into a closed mold whose temperature was controlled at 50℃. . When the mold was opened 120 seconds later, the resin molding was sufficiently cured and could be easily removed from the mold without breaking. Next, 140℃ x 2h + 180℃ x 2h
After curing, the physical properties of the molded product were as follows. Appearance No cracks, blisters, etc. Heat deformation temperature >250℃ Density 1.32g/cm ^3Barcol hardness 56 Tensile strength 1350Kg/cm ^3Tensile modulus 55500Kg/cm ^3Izotsu impact strength, notched 2.1Kg・cm/ cm ³ Tensile strength retention rate after 3 months at 200°C 81% Flammability test UL94HB Self-extinguishing property As is clear from the above explanation, the following effects can be obtained by the present invention. (1) Polyisocyanurate-based resin molded products with better heat resistance than polyisocyanates and compounds containing ethylenically unsaturated bonds can be obtained. (2) Simultaneous polymerization of polyisocyanate and an ethylenically unsaturated bond-containing compound can be rapidly performed, and polyisocyanurate-based heat-resistant resin can be molded efficiently. (3) A heat-resistant polyisocyanurate resin whose main components are polyisocyanate and a compound containing an ethylenically unsaturated bond can be efficiently molded using a two-component reaction injection or injection molding machine.

Claims (1)

[Claims] 1 When molding with a two-component reaction injection or injection molding machine, the first component is a liquid mixture of an organic polyisocyanate and/or isocyanate group-containing prepolymer and an epoxy compound, the second component is an ethylenically unsaturated bond-containing compound, After injection molding or injection molding using a liquid mixture of an aziridine compound and a tertiary amine, the post-cure starting temperature is set at 110~110°C.
A method for molding polyisocyanurate-based heat-resistant resin, characterized by a temperature of 170°C.