JPS63230723A - Reaction injection molding - Google Patents

Abstract

PURPOSE:To produce a void-free molding excellent in elongation, etc., by performing reaction injection molding of a feed component containing a high-MW active hydrogen compound and a specified chain extender and another feed component containing a polyisocyanate compound. CONSTITUTION:A synthetic resin molding is produced by reaction injection molding of at least two components, i.e., a feed component containing a high-MW active hydrogen compound (e.g., polyether polyol) and a chain extender and, optionally, a catalyst and a blowing agent and another feed component containing a polyisocyanate compound (e.g., 4,4'-diphenylmethane diisocyanate), by using a chain extender comprising a compound obtained by performing addition reaction of a polyamine with a cyclic carbonate, a cyclic amide or a cyclic ester and having an MW <=500 (e.g., xylylenediamine/ethylene carbonate adduct) or a combination thereof with another chain extender. A molding having a void-free surface and excellent elongation, etc. can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a reaction injection molding method for molding polyurethane urea elastomer molded articles.

[Prior Art] The production of synthetic resin molded articles by the reaction injection molding method is well known and is widely used, in particular, for the production of polyurethane resin molded articles including polyurethane elastomers. Application to synthetic resins other than polyurethane resins is also known; for example, application to polyamide resins, epoxy resins, unsaturated polyester resins, etc. is being considered, and some of them have been put into practical use by zero-reaction injection. The molding method involves mixing at least two fluid raw materials that can rapidly react to form a synthetic resin when mixed, immediately before a mold, and immediately injecting the synthetic resin into the mold. This is a molding method that focuses on forming Mixing of fluid raw material components is usually carried out by impingement mixing, and in order to achieve more uniform mixing, it is also common to inject the mixture into a mold through an after-mixing mechanism. below,
A mixture of at least two fluid raw material components is referred to as a reactive mixture.Although the present invention will mainly be described below with regard to the production of polyurethane-based elastomer molded articles by reaction injection molding, other polyurethane-based synthetic resins may be used. (For example, semi-rigid foam) and polyurea resins.

By reaction injection molding using at least two components: a raw material component containing a high molecular weight active hydrogen compound such as a relatively high molecular weight polyol, a chain extender, and optionally a catalyst and a blowing agent, and a raw material component containing a polyisocyanate compound. Methods for producing polyurethane elastomers such as polyurethane elastomers and polyurethaneurea elastomers are known. Typical examples of high molecular weight active hydrogen compounds are relatively high molecular weight polyols, especially polyether polyols.

The chain extender is a relatively low molecular weight polyhydric alcohol or polyamine, which is also a type of active hydrogen-containing compound.

The use of a catalyst is usually essential and is usually added to the active hydrogen compound-containing raw material component, but it can also be added to the incyanate compound-containing raw material component. The use of a small amount of a blowing agent such as a halogenated hydrocarbon blowing agent to produce a microcellular polyurethane elastomer is a commonly used means for improving moldability. The density of the bucrocellular polyurethane-based elastobu obtained using this small amount of blowing agent is usually 0.
It is at least 8 g/cm3, particularly at least about 0.9 g/cm3. Especially large amounts of reinforcing fibers.

Unless flaky fillers or powder fillers are added, the upper limit is usually 1.2 g/cm3 or less, especially about 1.15 g.
/cm3 or less. The density of the non-foamed polyurethane elastomer is also typically within the above range. It is also known to perform reaction injection molding by dividing the active hydrogen-containing compound-containing raw material component into two or more parts and using three or more components in total, including the isocyanate compound-containing raw material component.

[Problems to be Solved by the Invention] Polyurethane elastomers do not have sufficient heat resistance, and improvement is desired. In general, the heat resistance of polyurethane elastomers can be improved by: l) increasing the amount of highly polar components such as incyanate components to increase hardness;

2) Increased hardness by adding filler.

3) A trifunctional or higher functional active hydrogen component or an incyanate component is blended to perform high-order crosslinking.

However, these methods all involve deterioration of elongation properties, and it is extremely difficult to achieve both heat resistance and elongation properties.

Furthermore, it is known that one of the problems in reaction injection molding is that defects such as voids are likely to occur in molded products. A void is a relatively large air bubble that exists inside a molded product.A molded product containing voids has extremely non-uniform physical properties and tends to form four-parts on the surface, which poses a problem in terms of appearance. Additionally, if voids exist on the surface of the molded product,
The appearance becomes extremely poor due to depressions and missing parts.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems. A method for producing a synthetic resin molded article by reaction injection molding using at least two components: a component and a raw material component containing a polyisocyanate compound, in which a cyclic carbonate, a cyclic amide, or a cyclic ester is added to the polyamine as a chain extender. The present invention provides a reaction injection molding method characterized by using a compound having a molecular weight of 500 or less obtained by adding the same or another chain extender.

The polyamines used in the present invention include aliphatic and alicyclic polyamines having two or more primary amino groups or seven secondary amino groups;
Alternatively, aromatic polyamines are used. Preferably, a polyamine having a molecular weight of 500 or less, especially 400 or less and having 2 to 3 primary amine 7 groups is used. Mononuclear or polynuclear aromatic polyamines are preferred, especially diaminobenzene, toluene diamine, xylylene diamine,
Diaminobenzene derivatives having at least one alkyl group or electron-withdrawing group are preferred. As an alkyl group,
An alkyl group having 1 to 6 carbon atoms is suitable, and the electron-withdrawing group is preferably a halogen atom such as a chlorine atom, a nitro group, a cyano group, an alkoxycarbonyl group, an N-alkyl-substituted carbamoyl group, an alkoxysulfonyl group, etc. Preferable examples include toluenediamine, xylylene diamine, inphorone diamine, hexamethylene diamine, diaminochlorobenzene, diaminonitrobenzene, and diaminocyanobenzene.

As the cyclic carbonate, alkylene carbonates such as ethylene carbonate and propylene carbonate are suitable. As a cyclic amide, ε-caprolactam,
Lactams and alkyl-substituted lactams such as γ-butyrolactam and γ-valerolactam are suitable. In addition, cyclic esters include ε-caprolactane, butyrolactane,
Lactones such as δ-valerolactane and alkyl-substituted lactones are suitable. An amide bond is generated by the reaction of the amide 7 group with a cyclic ester or a cyclic 7 amide.

The amount of the cyclic carbonate, cyclic ester, or cyclic amide added is preferably in the range of from about 1 to (the number of 7-mino groups of the polyamine) per mole of polyamine, particularly preferably from about 1 mole to 1 mole of polyamine. (The number of amine 7 groups in the polyamine - 1). This leaves unreacted 7 amino groups, and this amino group has a reactivity different from that of the hydroxyl group formed by addition. This is considered to be one of the reasons why the effects of the present invention are exhibited. The molecular weight of the product is preferably 700 or less, particularly preferably 500 or less.

The above chain extenders can be used in combination with other chain extenders. The other chain extenders are preferably polyamines and low molecular weight diols, which are the starting materials, but are not limited to these. (low molecular weight polyethers), polyamines other than those mentioned above, etc. For example, by reacting 1 mole of the polyamine with less than 1 mole of the cyclic carbonate, a mixture of the adduct and unreacted polyamine is obtained, which is used as a chain extender as it is or together with other chain extenders. be able to. Of course, the polyamine may be prepared separately from the adduct, the molecular weight of which is 400.
Below, 200 or less is particularly preferable.

In the present invention, polyamines which conventionally could not be used as chain extenders for reaction injection molding can be used in combination with the above-mentioned adduct.

Examples of such polyamines include polyamines whose reactivity is not suppressed or whose reactivity is hardly suppressed, such as toluene diamine, xylylene diamine, hexamethylene diamine, and inphoron diamine. Of course, conventionally used polyamines whose reactivity is suppressed (eg, diethyltoluenediamine, diaminochlorobenzene, etc.) can also be used as the polyamine.

Of course, conventionally used polyol chain extenders can also be used. Examples of polyol chain extenders include ethylene glycol and 1,4-butanediol. The amount of the specific chain extender in the present invention relative to the total amount of all chain extenders is required to be at least 5% by weight, preferably at least 20% by weight, most preferably a majority to 100% by weight. Ru.

As the high molecular weight active hydrogen compound, a high molecular weight polyol having two or more hydroxyl groups is suitable. However, the use of high molecular weight active hydrogen compounds having two or more amine groups or an amino group and a hydroxyl group is also known, such as those having an amine 7 group at the end as described in JP-A-58-103521. Polyoxyalkylene compounds (hereinafter referred to as aminated polyethers) can also be used. The average molecular weight per active hydrogen-containing group (i.e., hydroxyl group and/or amino group) of the high molecular weight active hydrogen compound is about 60
The number of active hydrogen-containing groups per molecule is preferably 0 to 4,000, particularly about 800 to 3,000, and the average number of active hydrogen-containing groups per molecule is preferably 2.0 to 4.0, particularly about 2.0 to 3.5. be. As the high molecular weight active hydrogen compound, polyether polyols, mixtures of polyether polyols as a main component with other high molecular weight polyols, and polymer polyols based on polyether polyols are most preferred.As polyether polyols, polyhydric initiators are most preferred. A polyether polyol obtained by adding a monoepoxide such as alkylene oxide or tetrahydrofuran to a polyvalent initiator is suitable, and a polyether polyol obtained by adding propylene oxide and/or butylene oxide together with ethylene oxide to a polyvalent initiator is particularly preferable. For application to zero-reaction injection molding, the presence of highly reactive hydroxyl groups, i.e. primary hydroxyl groups, is necessary, and in the case of polyether polyols using monoepoxides, usually at least about 5% by weight at the terminal positions of the polyether chain. The presence of an oxyethylene group is considered almost essential. The higher the proportion of terminal oxyethylene groups, the higher the proportion of primary hydroxyl groups and the higher the reactivity, but the higher the proportion of oxyethylene groups, the higher the hydrophilicity of the polyether polyol, which in turn increases the water absorption of the polyurethane elastomer. becomes high, causing a decrease in water absorption dimensional properties. Therefore, the upper limit of the amount of oxyethylene groups present in the polyether polyol is suitably about 35% by weight, and particularly preferably about 25% by weight. However, this is not the case when producing hydrophilic polyurethane. . It is almost essential that at least 5% by weight of oxyethylene groups be present at the ends of the polyether chains, but they may also be present inside the polyether chains. The polyether polyol may be a mixture of two or more polyether polyols having different numbers of hydroxyl groups and molecular weights, and in particular, a mixture of two or more polyether polyols containing polyether diol or polyether triol as the main component or with other polyether polyols. Mixtures are preferred.

The polybo polyol is preferably a polymer polyol based on the above-mentioned polyether polyol, particularly a polymer polyol obtained by polymerizing at least one of 7-acrylonitrile, styrene, and other vinyl monomers in a polyether polyol. . others,
Polymer polyols obtained by polymerizing vinyl monomers in polyether polyols containing unsaturated groups, polyols containing condensation polymers obtained by carrying out condensation polymerization in polyether polyols, and polyols containing other polymer components can also be used. . Other high molecular weight polyols that can be used in combination with polyether polyols include hydroxyl group-containing hydrocarbon polyols such as butadiene homopolymers and copolymers having two or more hydroxyl groups, and polyester polyols. The combined use of is effective in improving the water absorption dimensional properties of polyurethane elastomers.

The aminated polyether is a compound obtained by converting some or all of the hydroxyl groups of the above-mentioned polyether polyol or polyether polyol without an oxyethylene group at the end to 7-min, and it can be used alone or in a polyether polyether. It can be used in combination with ether polyol etc.

The amount of chain extender relative to the total of high molecular weight active hydrogen compound and chain extender should be at least 3% by weight. The larger the amount of chain extender, the harder the molded product will be obtained (if the high molecular weight active hydrogen compound is the same).In order to obtain a molded product with good heat resistance, it is necessary to In the present invention, the amount of chain extender is preferably 5 to 50%.
% by weight is preferred, in particular 10-45% by weight, and in order to obtain particularly hard molded products, 20-45% by weight is used.

Modified or unmodified aromatic polyisocyanates are suitable as the polyisocyanate compound, and in some cases, other polyisocyanate compounds may be used alone or in combination with aromatic polyisocyanates and the like. As the aromatic polyisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylisocyanate, tolylene diisocyanate, etc. are suitable, and diphenylmethane diisocyanate consisting of 4,4'-diphenylmethane diisocyanate and its isomers is particularly suitable. Although these can be used as unmodified products, it is common to use modified products for application to reaction injection molding methods. Modified products include, but are not limited to, prepolymer-type modified products and carbodiimide-type modified products.The amount of the polyisocyanate compound used is approximately 9 in inocyanate index.
0 to 120, especially about 95 to 110 are suitable.

The use of catalysts is usually essential in the production of polyurethane elastomers. As a catalyst, a tertiary amine catalyst or an organic tin compound is usually used, and a blowing agent is often used to improve the filling properties of the reactive mixture into a mold. Polyurethane elastomers obtained using relatively small amounts of blowing agents are microcellular (
Foaming agents called elastomers (polyurethane-based) include trichlorofluoroethane, methylene chloride, other halogen (If-based Kitamoto-based blowing agents) and water, and both are often used together, especially halogenated Hydrocarbon blowing agents are preferably used in amounts up to about 15 parts by weight, particularly from about 2 to 10 parts by weight, based on 100 parts by weight of high molecular weight active hydrogen compound.

Polyurethane elastomers can be produced by using any additives in addition to the above raw materials. Optional additives include fillers, colorants, ultraviolet absorbers,
These include light stabilizers, antioxidants, and flame retardants. Examples of the filler include inorganic fibers such as glass fiber and wollastonite, organic fibers such as synthetic fibers, calcium carbonate, other powder fillers, mica, and other tabular fillers.

The amount of these fillers to be filled is approximately 30% for all synthetic resin raw materials because the larger the filling amount, the more problems arise with the viscosity and operability of the raw material components.
These additives are preferably added to the active hydrogen compound-containing raw material component, but those that are non-reactive with incyanate groups are preferably added to the incyanate compound-containing raw material component. can also be blended.

The synthetic resin molded article obtained by the present invention, particularly the polyurethane elastomer molded article, can be used for various purposes.

It is particularly suitable for automobile exterior parts, such as bumper shells, fascias, fenders, and door panels. but.

The application is not limited to this, but it can also be used for other automotive parts, housings for electronics or electronic equipment, and other applications.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Examples The examples described below were conducted using the following raw material components and molding tests.

1) High molecular weight polyol A: Oxyethylene group content 25% by weight with an oxyethylene group at the end, hydroxyl value 28 using glycerin as an initiator
Uses polyoxypropylenoxysho tyrene triol.

2) Incyanate C The amount of the prepolymer-type modified diphenylmethane diisocyanate component having an incyanate content of 26.0% by weight is such that the equivalent ratio to the active hydrogen component is 1.05.

(Molding test) Using a reaction injection molding device (high pressure foaming machine), the discharge output was 15
0 kg/cm2, discharge rate 15 ± 5 kg/min, and the liquid temperature of each component was adjusted to 30 to 40°C, and reaction injection molding was performed.The mold cavity has a size of 350 mm x 35 hm, and a wall thickness of 31 mm. The temperature was adjusted to 60-70°C. The mold was removed 30 seconds after injection, and the density, tensile strength, and heat sag of the molded product were measured.

(Tensile test) 50% modulus (kg/cm2), tensile strength (kg
/c]2), elongation (%), No. 2 dumbbell, tensile speed 2
Measurement was performed at a speed of 50 mm/min.

(Heat sag (thermal sag)) A 25 x 125 x 3+ m sample was left at 120°C x thr with a 100 mm overhang.
After cooling for 30 minutes at room temperature, the sagging distance was measured.

Example 1 100 g of ethylene carbonate dissolved at 40° C. in 182 g of 2,5-diaminochlorobenzene was added dropwise and stirred. After standing at 40° C. for about 6 hours, 25 parts of the reactant was dissolved in 75 parts of high molecular weight polyol A, and 0.1 part of dibutyltin dilaurate was mixed thereinto to form an active hydrogen component.

The equivalent ratio of Incyanate C to this active hydrogen component is 1.0.
Molding was carried out using an amount of 5, and the temperature was 120°Clhr.
After heat treatment, 50% tensile modulus 135kg/cm2
, tensile strength was 305 kg/cm2, and E B was 320%. Also, heat sag! It was 5.1 mm.

Example 2 In a reaction vessel capable of pressurized reaction, 100 g of N-methyl-2-pyrrolidone and 124 g of 2,4-toluenediamine
After sealing, the reactor was heated to 120° C. and reacted with stirring day and night.

10 parts of this reactant is dissolved in 78 parts of high molecular weight polyol A, and 12 parts of ethylene glycol and 0.1 part of dibutyltin dilaurate are mixed thereinto to form an active hydrogen component.

The equivalent ratio of Incyanate C to this active hydrogen component is 1.0.
When molding was performed using the amount of 5, and the tensile strength was measured after heat treatment at 120℃lhr, the 50% tensile modulus was 135 kg/cm2, and the tensile strength was 295 kg/cm.
m2 and elongated to 305 pallets. Also, the heat sag is 19
It was a departmental level.

Example 3 In a reaction vessel capable of pressurized reaction, ε-caprolactone 10
0 g and 107 g of 2,4-toluenediamine were taken, and after the container was sealed, it was heated to 120° C., and the reaction was carried out with stirring day and night. 25 parts of this reactant are dissolved in 75 parts of high molecular weight polyol A, and 0.1 part of dibutyltin dilaure is mixed therewith to form an active hydrogen component.

The equivalent ratio of Incyanate C to this active hydrogen component is 1.0.
Molding was carried out using the amount of 5, 120°01hr
After the heat treatment, the tensile strength was measured and found that the 50% tensile modulus was 115 kg/c+s2 and the tensile strength was 289 kg.
/cm2, elongation 310L! : Natsuta, Maf=, heat sag was IE+sm.

Example 4 44 parts of ethylene carbonate dissolved at 40°C was added dropwise to 138 parts of l-xylylene diamine and stirred. - After standing for day and night, 25 parts of the reactant was dissolved in 75 parts of high molecular weight polyol A (dibutyltin dilaure).
0.1 part is mixed to form an active hydrogen component.

The equivalent ratio of isocyanate C to this active hydrogen component is 1.0.
At a ratio of 5, the cavity internal dimension is 350 x 120
Injected for 2.5 seconds into a 10mm x 10mm mold, 434
A molded product with no molding defects was obtained.

Comparative Example 1 16 parts of ethylene glycol, high molecular weight polyol A13
4 parts, 0.25 parts of triethylenediamine, and 0.07 parts of dibutyltin dilaurate were dissolved to form an active hydrogen component.

The equivalent ratio of this active hydrogen component and incyanato C is 1.
05, heat treated at 120°C for 1 hour, and measured for tensile strength. 50% modulus 142 kg
/cm2, tensile strength 248kg/cm2, elongation 247z
It became. In addition, the heat sag was 29 mm. Comparative Example 2 - 3 parts of xylylene diamine, 13 parts of ethylene glycol
parts, 84 parts of high molecular weight polyol A, 0.25 parts of triethylenediamine, and 0.0 parts of dibutyltin dilaurate.
7 parts were dissolved to form an active hydrogen component.

The equivalent ratio of this active hydrogen component and incyanato C is 1.
Using the amount of 05, the cavity inner dimension is 350
The method was tried by injecting into a 120 x 10 mm mold for 2.5 seconds, but resulted in a molding with about 20% unfilled area.

Claims (1)

[Scope of Claims] 1. Using at least two components: a raw material component containing a high molecular weight active hydrogen compound and a chain extender and optionally containing a catalyst and a blowing agent, and a raw material component containing a polyisocyanate compound, In a method for producing synthetic resin molded products by reaction injection molding, a compound with a molecular weight of 500 or less obtained by adding a cyclic carbonate, cyclic amide, or cyclic ester to a polyamine as a chain extender;
or a reaction injection molding process characterized by the use thereof and other chain extenders. 2. The method according to claim 1, wherein the polyamine is a diamine having a primary amino group. 3. The method according to claim 1, wherein the addition product is a compound having one unreacted amino group.