JPH0243776B2 - ASETAARUJUSHISOSEIBUTSU - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a modified acetal resin, and particularly aims to provide a glass-reinforced acetal resin having excellent mechanical strength and low mold shrinkage. Due to its excellent mechanical properties, abrasion resistance, and chemical resistance, acetal resin is molded into gears, gears, springs, and other shapes and is used in a wide range of applications. Even if reinforcing materials such as fibers and glass powder are mixed, it has the disadvantage that it is difficult to achieve a reinforcing effect compared to other resins such as nylon, polycarbonate, and polyethylene terephthalate. Several methods have been proposed to improve this point (Japanese Patent Laid-Open No. 46-6388, Japanese Patent Publication No. 46-25259, Japanese Patent Publication No. 55-18741), but the present inventors have By adding and blending polyfunctional cyanate esters or mixtures or pre-reactants of polyfunctional cyanate esters and polyfunctional maleimides, the reinforcing effect of glass fibers and powder on acetal resin can be greatly improved. The present invention was achieved by discovering that it is possible to do this. The polyfunctional cyanate esters used in the composition of the present invention are polycyanate ester compounds represented by the following general formula (1) having two or more cyanate ester groups in the molecule, formula R ₁ ( -O-C≡N)m...(1) (In the formula, R ₁ is an aromatic polyvalent organic group described later, and the cyanate ester group is directly bonded to the aromatic ring of the organic group R ₁ . m is an integer greater than or equal to 2, usually
Represents an integer less than or equal to 10. ) and oligomers (prepolymers) derived from this polycyanate ester compound. Here, the aromatic polyvalent organic group represented by R ₁ is (1) an aromatic hydrocarbon group having 6 to 16 carbon atoms, exemplified by benzene, naphthalene, anthracene, birene, etc.; 2) An organic group formed by directly bonding multiple benzene rings represented by biphenyl; (3) An aromatic group represented by the following general formula (3) in which multiple benzene rings are connected via a bridge. Ring-containing organic group; (In the formula, Y is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 14 carbon atoms; an aromatic hydrocarbon group represented by phenylene group and xylylene group; oxygen atom; sulfur atom; carbonyl group ;Sulfonyl group;
A sulfinyl group; a phosphonyl group; a phosphinyl group; a polyvalent bonding group exemplified by an imino group, an alkyleneoxyalkylene group, etc. ) (4) Refers to the residue of a benzene polynuclear body (generally, one having 10 or less nuclei is preferably used) obtained by reacting phenol and formaldehyde.
In these polyvalent organic groups, the aromatic ring may be substituted with an inert substituent such as an alkyl group or an alkoxy group. Examples of the aromatic ring-containing organic group include diphenylmethane, 2,2-diphenylpropane, diphenyl ether, diphenyl methylene ether, diphenylthioether, diphenyl ketone, diphenylamine, diphenyl sulfoxide, diphenyl sulfone, triphenyl phosphite, Examples include polyvalent organic groups derived from triphenyl phosphate and the like. Among them, diphenylalkanes, especially 2,2-
Diphenylpropane is the most commonly used. The polycyanate ester compound represented by the general formula (1) is generally prepared by a known method (for example, as taught in Japanese Patent Publication No. 1928-1973) in which a corresponding polyvalent phenol compound is reacted with cyanogen halide. prepared. Specific examples of polyfunctional cyanate esters include 1,3- or 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-, 1,4-, 1 ,6-,
1,8-, 2,6- or 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4'-dicyanatobiphenyl, bis(4-dicyanatophenyl) Methane, 2,2-
Bis(4-cyanatophenyl)propane, 2,
2-bis(3,5-dichloro-4-cyanatophenyl)propane, 2,2-bis(3,5-dibromo-4-cyanatophenyl)propane, bis(4-cyanatophenyl) ether, Screw (4
-cyanatophenyl)thioether, bis(4
-cyanatophenyl)sulfone, tris(4-
cyanatophenyl) phosphite, tris(4
- cyanatophenyl) phosphate, and benzene polynuclear polycyanate compounds obtained by the reaction of a phenolic resin and cyanogen halide (for example, as taught in Japanese Patent Publication Nos. 11712-1971 and 9433-55). can. Furthermore, the special public interest rates are as follows: 41-1928, 43-18468, 44-4791, 46
Cyanic acid esters described in JP-A-15516, 46-41112, and 47-26853, or Japanese Patent Application Laid-Open No. 51-63149 are also included in the category of polyfunctional cyanic esters used in the present invention. From the viewpoint of being easily available and imparting good properties to the final resin, it is preferable to use 2,2-bis(4'-hydroxyphenyl)propane (bisphenol A), which has a symmetrical structure and a bridged portion. 2 that does not have a fused ring
Divalent cyanate ester compounds derived from monovalent phenols are particularly preferably used. Also,
Polycyanate compounds obtained by reacting an initial condensate of phenol and formaldehyde with cyanogen halide are also useful. In the composition of the present invention, the above-mentioned polycyanate ester compound may be used alone, or an oligomer (prepolymer) derived from this polycyanate ester compound may be used alone, or a mixture of these may be used. The above prepolymer is obtained by polymerizing a polycyanate ester compound in the presence of a catalyst such as a mineral acid, a Lewis acid, a salt such as sodium carbonate or lithium chloride, or a phosphate ester such as tributylphosphine. These prepolymers are formed by trimerization of the cyano groups in the cyanate ester.
-It preferably has a triazine ring in its molecule and has an average molecular weight of 400-6000. For example, commercially available "cyanate ester resins" are mixtures of 2,2-bis(4'-cyanatophenyl)propane and its prepolymers obtained from bisphenol A and cyanogen halides. Such "cyanate ester resins" are preferably used in the present invention. The polyfunctional maleimide used in the composition of the present invention is a polymaleimide compound represented by the following general formula (2) having two or more maleimide groups in the molecule. (In the formula, R ₂ is an aromatic or aliphatic polyvalent organic group described below, X ₁ and X ₂ are hydrogen atoms,
It is a halogen atom or a lower alkyl group, and n represents an integer of 2 or more, usually 10 or less. ) and oligomers (prepolymers) derived from this polymaleimide compound. Here, the aromatic or aliphatic polyvalent organic group represented by R ₂ is (1) a chain or cyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms; (2) phenylene (3) An organic group formed by directly bonding multiple benzene rings represented by biphenyl; 4) an aromatic ring-containing organic group represented by the general formula (3) in which a plurality of benzene rings are connected via a bridge; (5) a melamine residue; (6) an organic group obtained by reacting aniline with formaldehyde; Refers to the residues of benzene polynuclear bodies (usually those having 10 or less nuclei are used). In these polyvalent organic groups, the chain aliphatic hydrocarbon group, aliphatic ring, or aromatic ring may be substituted with an inert substituent such as an alkyl group or an alkoxy group. Examples of the aromatic ring-containing organic groups include diphenylmethane, diphenylpropane, diphenyl ether, diphenyl dimethylene ether, diphenyl thioether, diphenyl ketone, diphenylamine, diphenyl sulfoxide, diphenyl sulfone, triphenyl phosphite, and triphenyl phosphite. Examples include polyvalent organic groups derived from ate and the like. Among them, diphenylmethane is the most commonly used. These polyfunctional maleimides or maleic anhydrides are reacted with a polyamine having two or more amino groups to prepare a polymaleamic acid, and then the polymaleamic acid is cyclodehydrated, which is a method known per se. be able to. In the composition of the present invention, the above polymaleimide compound or a prepolymer derived from this polymaleimide compound may be used alone, or a mixture thereof may be used. In the resin composition of the present invention, when the above-mentioned polyfunctional maleimide and polyfunctional cyanate ester are used together, they can be used in the form of a mixture, or they can be preliminarily reacted. It can also be used in the form of a prepolymer. Of course, a mixture of a prepolymer and a monomer may also be used. A prepolymer obtained by reacting a polyfunctional maleimide with a polyfunctional cyanate ester is a liquid product with surprisingly low viscosity, and by using such a prepolymer, the resin temperature of the present invention can be lowered. Not only is it extremely easy to prepare, but it also has many advantages in terms of handling and processability when using the resin composition for various purposes. Therefore, embodiments of the present invention using the above prepolymers are preferred in practice. The acetal resin used in the composition of the present invention is made from substantially only oxymethylene units produced from formaldehyde monomers or cyclic oligomers such as their trimers (trioxanes) or tetraoxanes (tetraoxanes). An oxymethylene homopolymer and an oxymethylene unit produced from the above raw materials and a cyclic ether such as ethylene oxide, propylene oxide, epichlorohydrin, 1,3-dioxolane, 1,3-dioxepane, glycol formal, diglycol formal, etc. Includes oxymethylene copolymers consisting of C ₂ or more oxyalkylene units. As the glass fiber or glass powder, untreated products or commercially available products treated with aminosilane treatment, epoxysilane treatment, etc. can be used. Glass powder also includes beads. The composition ratio of each component in the composition of the present invention is:
Acetal resin, 60 to 90 parts by weight, 0.1 to 10 parts by weight of polyfunctional cyanate esters or a mixture or preliminary reaction of polyfunctional cyanate esters and polyfunctional maleimides, glass fiber or powder 10
A ratio of ~40 parts by weight is suitable. Although it is not necessarily necessary to add a curing catalyst to the composition of the present invention, it is preferable to use it from the viewpoint of workability during molding, etc. Such curing catalysts include triethylenediamine, N,N-dimethylpenzylamine, Tertiary amines such as N-methylmorpholine and tri-n-butylamine, imidazoles such as 2-methylimidazole and 2-phenylimidazole, organic compounds such as zinc octylate, tin octylate, zinc naphthenate, and cobalt naphthenate. One or more combinations of metal salts or organic peroxides such as benzoyl peroxide, dicumyl peroxide, t-butyl hydroperoxide are suitable, and the use of tertiary amines is particularly preferred. When adding a curing catalyst, the appropriate amount is 0.01 to 0.2% by weight based on the mixture or preliminary reaction of polyfunctional cyanate esters or polyfunctional cyanate esters and polyfunctional maleimides. be. In addition to the above-mentioned compositions, the composition of the present invention includes:
Known heat stabilizers, light stabilizers, antioxidants, etc. can be added as necessary and within a range that does not impair the effects of the present invention. The method for producing the acetal resin composition of the present invention includes mixing all the components at once, or after pre-mixing two components (including a method of attaching one component to the surface of glass fiber or glass powder), together with the remaining components. A method of melting and kneading is suitable. General kneading machines such as various extruders, kneaders, Banbury mixers, and mixing rolls are used for melt-kneading, but each component is dry-blended before kneading and then supplied to these machines. is preferable. The appropriate melt-kneading temperature is 180 to 240°C. By curing the acetal resin composition of the present invention, the acetal resin composition has various physical properties such as mechanical properties, abrasion resistance, and chemical resistance that are inherent to the acetal resin without impairing them, and it also has glass fibers and glass powder. It is possible to obtain a resin that fully exhibits the reinforcing effect of the method, has particularly excellent mechanical strength, and has low mold shrinkage. Although the reason is not necessarily clear, polyfunctional cyanate esters, mixtures of polyfunctional cyanate esters and polyfunctional maleimides, and pre-reacted products generate gas, moisture, etc. when heated. It hardens without any damage to form a stable ring structure such as a triazine ring, triazine-imidazole ring, or oxadiazole ring, and is presumed to act to couple the acetal resin with the glass surface. Note that polyfunctional cyanate esters and polyfunctional maleimides have the characteristics of low toxicity and easy handling, and are therefore extremely advantageous in terms of workability during resin production. Example 1 An acetal copolymer with an MI value of 9.2 containing 2.5% by weight of comonomer units derived from ethylene oxide (manufactured by Mitsubishi Gas Chemical Co., Ltd., Iupital F20)
-01) 3.5Kg, 2,2'-bis(4-cyanatophenyl)propane 70g, triethylenediamine,
After mixing 0.36 g and 1.17 kg of glass fiber (chopped strand) in a tumbler type blender for 3 minutes, the mixture was fed to a 40 mm diameter single screw extruder and heated and extruded at a resin temperature of 225°C. The thus obtained glass fiber-containing acetal copolymer was heated at a resin temperature of 219°C and an injection pressure of 800Kg/cm ² .
Table 1 shows the results of injection molding at a mold temperature of 93° C. and measuring the tensile strength, elongation, and heat distortion temperature of the molded product. For comparison, the same procedure as in Example 1 was conducted except that 2,2'-bis(4-cyanatophenyl)propane was not used, and the results are shown in Table 1 as Comparative Example 1.

[Table] Example 2 Instead of 70 g of 2,2'-bis(4-cyanatophenyl)propane, 7 g of 2,2'-bis(4-cyanatophenyl)propane, maleic anhydride, and 4,4 Example 1 was carried out in exactly the same manner as in Example 1, except that a mixture with 63 g of bismaleimide obtained from '-bisaminophenylmethane as a raw material was used. As a result, the tensile strength was 1210 Kg/cm ² and the elongation was 3%. Example 3 60 g of 2,2'-bis(4-cyanatophenyl)propane was dissolved in acetone 2, 1.0 kg of glass fiber was immersed in this solution, and the acetone was evaporated at room temperature to dissolve 2,2'-bis(4-cyanatophenyl)propane. A glass fiber having surface adhesion of '-bis(4-cyanatophenyl)propane was obtained. This glass fiber was dry blended for 3 minutes with 3.0 kg of the same acetal copolymer used in Example 1, then heated and extruded and kneaded under the same conditions as in Example 1, and further injection molded. The tensile strength and elongation of the molded article thus obtained were 1280 Kg/cm ² and 4%, respectively. Examples 4, 5 and Comparative Example 2 3.5 kg of acetal copolymer was mixed with acetal homopolymer (manufactured by Asahi Kasei Corporation, Tenatsuku 5010),
The results were shown in Table 2 as Examples 4 and 5 and Comparative Example 2, which were carried out in exactly the same manner as in Examples 1 and 2 and Comparative Example 1, except that the weight was changed to 3.5 kg.

【table】

Claims (1)

[Scope of Claims] 1 (a) an acetal resin, (b) (1) a polyfunctional cyanate ester, (2) a mixture of a polyfunctional cyanate ester and a polyfunctional maleimide, or (3) a polyfunctional cyanate ester; An acetal resin composition prepared by adding a preliminary reaction product of a functional cyanate ester and a polyfunctional maleimide, and (c) glass fiber or glass powder. 2 Polyfunctional cyanate esters have the following general formula
The acetal resin composition according to claim 1, which is a polycyanate ester compound represented by (1) and/or a prepolymer thereof. Formula R ₁ (-O-C≡N)m...(1) (wherein, R ₁ is an aromatic polyvalent organic group,
The cyanate ester group is directly bonded to the aromatic ring of the organic group R ₁ , and m represents an integer of 2 or more. 3. The acetal resin composition according to claim 1, wherein the polyfunctional maleimide is a polymaleimide compound represented by the following general formula (2) and/or a prepolymer thereof. formula (In the formula, R ₂ is an aromatic or aliphatic polyvalent organic group, X ₁ and X ₂ are a hydrogen atom, a halogen atom, or a lower alkyl group, and n represents an integer of 2 or more. ) 4 The acetal resin is an oxymethylene homopolymer consisting essentially only of oxymethylene units or an oxymethylene copolymer consisting of oxymethylene units and _C2 or more oxyalkylene units. Acetal resin composition. 5. A patent claim in which the content ratios of (a), (b) and (c) are (a); 60 to 90 parts by weight, (b); 0.1 to 10 parts by weight, and (c); 10 to 40 parts by weight. Acetal resin composition according to scope 1. 6. The acetal resin composition according to claim 1, which contains tertiary amines, imidazoles, organic metal salts, or organic peroxides as a curing catalyst.