JP3102971B2 - Polyacetal resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a polyacetal resin obtained by blending a specific thermoplastic vinyl copolymer with a polyacetal resin, and further blending a polyisocyanate compound and a compound having a primary or secondary amine. An object of the present invention is to provide a composition in which the compatibility, dispersibility, and interfacial adhesion between the resin and the vinyl resin are improved, the respective disadvantages are compensated, and various properties are improved.

[0002]

2. Description of the Related Art Polyacetal resins are excellent in moldability and have well-balanced mechanical properties, electrical properties, heat resistance, chemical resistance, friction and wear characteristics, and the like. Because of its excellent fatigue resistance as a plastic material, it is used in a very wide field as a typical engineering resin. However, since polyacetal resin has high crystallinity, it has a large molding shrinkage, a high specific gravity, and a problem that needs to be improved depending on the purpose of use, such as poor weather resistance, acid resistance, and adhesiveness. On the other hand, vinyl resins are excellent in weather resistance, acid resistance, molding shrinkage, etc., and have a small specific gravity and light weight, but generally have a low softening point and have limited mechanical properties. In general, in modifying the physical properties of a thermoplastic resin, it is common practice to compensate for the disadvantage by blending another resin having a property to supplement the physical properties, and the purpose is often achieved. However, polyacetal resins are different from general thermoplastic resins, and when other thermoplastic resins are blended, the mutual compatibility and dispersibility between the resins are particularly poor, and the adhesion at the interface between the two phases is insufficient.
In addition, phase separation at the interface is apt to occur, and when a molded article is formed, the surface layer may be peeled off. In addition, there is a problem that the strong elongation at the weld portion is remarkably reduced. Is extremely difficult to modify. The blending with general vinyl resins is no exception, one component is present as coarse particles and the adhesion at the interface between the two phases is insufficient, phase separation occurs at the interface, and surface peeling occurs when molded products are formed. However, there is a problem in practical use due to deterioration of mechanical properties. An object of the present invention is to provide a resin composition having good compatibility, dispersibility, and interfacial adhesion to a polyacetal resin from such a viewpoint, and improved in various properties such as mechanical properties and surface state.

[0003]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that a combination of a polyacetal resin and a specific modified vinyl copolymer, and a combination of two specific compounds as a dispersion improver. It has been found that the dispersibility of both resins is remarkably improved by coexistence and melt kneading, and the present invention has been accomplished. That is, the present invention provides (A) 97 to 10% by weight of a polyacetal resin and (B) a glycidyl ester of an α, β-unsaturated acid by copolysynthesis.
Olefin and / or styrene copolymer
Coalesced, itself thermoplastic and melt processable
, Thermoplastic vinyl copolymer having an epoxy group
(C) 0.1 to 10 parts by weight of a polyisocyanate compound or a modified product thereof per 100 parts by weight of a thermoplastic resin comprising 90% by weight.
The present invention relates to a resin composition obtained by mixing and melt-kneading 0.01 to 3 parts by weight of a compound having a primary or secondary amine and (D) a primary or secondary amine.

Hereinafter, the components of the present invention will be described. The polyacetal resin (A) used in the present invention, and a polymer compound having an oxymethylene group (-CH ₂ O-) as the main constituent unit, a polyoxymethylene homopolymer or an oxymethylene group as the main repeating units, Other structural units, for example, ethylene oxide, 1,3-dioxolan, 1,4-butanediol, copolymer containing a small amount of a comonomer unit such as formal, may be any of terpolymer, block polymer, The molecule may have not only a linear shape but also a branched or crosslinked structure, or a known modified polyoxymethylene into which another organic group has been introduced. There is no particular limitation on the degree of polymerization, and those having melt processability (for example, 190 ° C., 2160
The melt flow value (MFR) under a g load may be 1.0 to 100).

[0005] Next, a thermoplastic vinyl copolymer having an epoxy group to be blended with the polyacetal resin (A) in the present invention.
(B) is a copolymer obtained by copolymerizing an α , β-unsaturated acid glycidyl ester as a copolymer component with another vinyl monomer. Here, the glycidyl ester of α, β-unsaturated acid as a copolymer component is represented by the general formula (1)

[0006]

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(Wherein R is a hydrogen atom or a lower alkyl group), specifically glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, and the like, with glycidyl methacrylate being preferred. used. One of the preferable ones belonging to the modified vinyl copolymer (B) is a modified olefin copolymer. Such modified olefin-based copolymers include ethylene, propylene, butene-1, 3-methylbutene-1,
A copolymer of one or more of ethylene and α-olefin-based monomers such as 4-methylpentene-1 and the glycidyl ester of the α, β-unsaturated acid, wherein ethylene and α-olefin are the main components. (That is, containing 50 mol% or more)
And glycidyl ester of the above α, β-unsaturated acid
The further vinyl esters such as vinyl acetate, acrylic acid, methacrylic acid and derivatives thereof (such as methyl acrylate, methyl methacrylate, dimethylaminoethyl acrylamide), maleic acid / maleic anhydride and their derivatives (e.g., dimethyl maleate , Diethyl malate, etc.), butadiene, isoprene and the like. Particularly preferably, a polyethylene system having ethylene as a main structural unit, a polypropylene system having propylene as a main structural unit, or a ethylene ester or propylene as a main structural unit, vinyl esters such as vinyl acetate, acrylic acid and methacrylic acid or esters thereof. And an olefin-based copolymer containing as a copolymer component. Further, another preferable one belonging to the modified vinyl copolymer (B) used in the present invention is a modified styrene copolymer comprising styrene and a glycidyl ester of an α, β-unsaturated acid as described above. is there. Such a modified styrene-based copolymer is generally obtained mainly by styrene, and is obtained by a radical polymerization reaction or an ionic polymerization reaction together with the monomer compound of the general formula (1), and is formed by bulk polymerization, solution polymerization, suspension polymerization,
Any of those obtained by emulsion polymerization or the like can be used.
The modified styrenic copolymer used in the present invention is mainly composed of styrene (that is, contains at least 50 mol%), and the above α, β
-Reactive monomers such as other vinyl compounds and diene compounds may be copolymerized with the glycidyl ester of an unsaturated acid, or a rubber component may be introduced. In particular, styrene, α-methylstyrene, or those mainly
(I.e., containing 50 mol% or more) of the above α, β-unsaturated acid
Copolymers of acrylic acid esters, methacrylic acid esters, acrylonitrile, butadiene, chlorinated ethylene, and the like are preferably used together with ricidyl esters . Such a modified vinyl copolymer (B) may have not only a linear molecule but also a somewhat branched structure, and the degree of polymerization is not particularly limited. It is necessary that the material has processability, and in order to uniformly and finely disperse during melt-kneading, a material having good fluidity is preferable. A multiphase structure that is difficult to perform is not preferable because it is difficult to be divided into pieces while maintaining the original shape, and the adhesiveness of the interface is not sufficient. Modified vinyl copolymer (B)
The amount of the epoxy group-containing monomer constituting is from 0.5 to
It is preferable to contain 50% by weight, preferably 2 to 40% by weight.

When the content of the epoxy group is too large, the characteristics (cost, physical properties, etc.) of the vinyl resin are lost, and when the content is too small, the effects such as compatibility, dispersibility, adhesion and the like with the polyacetal resin are obtained. Is not preferred. The amount of the modified vinyl copolymer (B) is 3 to 90% by weight of the resin component.
Preferably 5 to 85% by weight, more preferably 5 to 50% by weight
It is. If each of the components (A) and (B) is too small or too large, a sufficient reforming effect cannot be obtained, which is not preferable.

In the present invention, the polyacetal resin (A) and the thermoplastic vinyl copolymer (B) having an epoxy group (B) are blended with the polyisocyanate compound or its modified product (C) when melt-kneaded. A compound having two or more isocyanate groups or isothiocyanate groups therein or a modified product thereof, preferably a diisocyanate or diisothiocyanate compound, or a dimer or trimer thereof. For example, 4,4′-methylenebis (phenyl isocyanate), 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 1,5- Naphthalene diisocyanate or their corresponding diisothiocyanates and their dimers, trimers, and even compounds in which the isocyanate group (-NCO) is protected in some form, etc. are all effective. Various properties such as discoloration degree,
Or, in consideration of safety in handling, 4,4′-methylenebis (phenylisocyanate), isophorone diisocyanate, 1,5-naphthalenediisocyanate,
Particularly preferred are 6-hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and modified products (or derivatives) such as dimers and trimers. The compounding amount of the polyisocyanate compound or its modified product (C) is 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, based on 100 parts by weight of the resin component. If the compounding amount is too small, a sufficient reforming effect cannot be expected,
If it is too large, the viscosity may increase due to a crosslinking reaction or the like, and stable characteristics cannot be obtained, which is not preferable.

The compound (D) having a primary or secondary amine of the present invention is preferably a heat-resistant, non-volatile compound, and a particularly preferred group of substances is an amidine such as dicyandiamide or melamine or a derivative thereof. Compounds, specifically, besides dicyandiamide and melamine, benzoguanamine, guanamine, 2,4-diamino-6-
Methyltriazine, N-butylmelamine, N-phenylmelamine, N-methylolmelamine, 2,4-diamino-
Examples include 6-butyltriazine, 2,4-diamino-6-benzyloxytriazine, and 2,4-dioxy-6-aminotriazine. Another group of preferred substances include piperidine compounds, specifically acetoxy-2,
2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine,
-Methoxy-2,2,6,6-tetramethylpiperidine, 4-
Benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4- Benzyloxy-2,2,6,6-tetramethylpiperidine, 4- (phenylcarbamoioxy)
-2,2,6,6-tetramethylpiperidine, bis (2,2,6,6
-Tetramethyl-4-piperidyl) oxalate, bis (2,2,6,6-tetramethyl-4-piperidyl) malonate, bis (2,2,6,6-tetramethyl-4-piperidyl)
Adipate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and the like are exemplified.

Also useful are pyrrole, aniline or derivatives thereof, hydrazine compounds, long-chain aliphatic amines and the like. The compounding amount of the compound (D) having a primary or secondary amine used in the present invention is based on 100 parts by weight of the resin component.
It is 0.01 to 3 parts by weight, preferably 0.05 to 2 parts by weight. If the amount is less than 0.01 part by weight, no effect on the dispersibility is recognized, and if it exceeds 3 parts by weight, physical properties are impaired and problems such as coloring are unpreferably caused.

The resin composition of the present invention comprises the above (C) and (D)
By mixing and kneading the components in combination and melt-kneading, the compatibility between the polyacetal resin (A) and the modified vinyl copolymer (B) has the effect of significantly improving the dispersibility, and (A) or (B)
The components are uniformly dispersed as extremely fine particles, and the adhesion at the interface is improved. This can be confirmed by observing the fracture surface of the composition molded article with an electron microscope. That is,
When the components (C) and (D) are not used together, the surface of the molded article is easily peeled off, and when the fracture surface is observed with an electron microscope, the interface can be clearly identified, especially when the fracture surface is observed. (1 μm or more, generally 2 μm or more) or as a layered two-phase separation structure, and it is recognized that poor adhesion at the interface is a cause of fracture. or,
When immersed in a reagent in which one resin dissolves, the resin phase is eluted, and this is recognized from the fact that cavities are formed. On the other hand, the vinyl copolymer having an epoxy group of the present invention
In the resin composition obtained by using (B) and further combining the components (C) and (D), the interface between the two resins can be hardly distinguished or very fine particles (particle size) in the same observation or treatment. 0.5 μ
m) or less, which suggests that the interface is not the cause of breakage, indicating that the specific resin composition of the present invention is excellent in dispersibility and interfacial adhesion.

[0013] Further, the resin composition of the present invention is as described above.
The component (B) itself has good compatibility with the polyacetal resin, and due to the presence of the components (B), (C) and (D), the component (B) has poor compatibility and dispersibility with the polyacetal resin. Resin components, for example, a general vinyl-based resin or polyester-based resin, a polyamide resin, a polyurethane resin, and the like, there is an advantage of improving the compatibility and dispersibility of the resin component. It is expected that the possibility of resin blending will be expanded and that the possibility of modification will be increased. From this point of view, the composition of the present invention can further incorporate many other thermoplastic resins, such as polyethylene, polypropylene, ethylene propylene rubber, ethylene-vinyl acetate copolymer,
Ethylene-ethyl acrylate copolymer, propylene
Olefinic resins such as maleic anhydride copolymer, polyoxyalkylene glycols such as polyethylene glycol and polypropylene glycol, polystyrene, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-based resins such as ABS resin, polyurethane-based Resins, polyamide resins, polyester resins and the like are particularly preferred. The blending amount of these thermoplastic resins is 50% by weight or less in the resin component,
It is preferably at most 40% by weight.

Further, in order to impart desired properties to the resin composition of the present invention without impairing its purpose, conventionally known additives such as lubricants, lubricants, nucleating agents, dyes and pigments, release agents,
Additives such as an antistatic agent, an antioxidant, a heat stabilizer, a weather (light) stabilizer, a hydrolysis stabilizer, various other general reinforcing agents, and fillers can be added.

The composition of the present invention can be prepared by various known methods, but at least (A), (B), (C) and (D) 4
It is necessary to heat and melt in the coexistence of the components and knead the mixture for at least 20 seconds.Specifically, the above-mentioned components and other additives as necessary are homogenized in advance by a mixer such as a tumbler or a Henschel mixer. Is generally supplied to a single-screw or twin-screw extruder and melt-kneaded, and an open roll, a Banbury mixer, a kneader, or the like may be used. The resin composition kneaded by these methods may be pelletized and then subjected to molding, or may be directly molded. The treatment temperature is 5 ° C to 100 ° C higher than the temperature at which the resin component melts, and particularly preferably 10 ° C to 60 ° C higher than the melting point. If the temperature is too high, decomposition or abnormal reaction occurs, which is not preferable. The melt-kneading time is at least 20 seconds to 10 minutes, preferably 1 to 5 minutes.

[0016]

Industrial Applicability The resin composition of the present invention has excellent compatibility and dispersibility between resin components, has no trouble due to poor dispersion such as surface layer peeling of molded articles, has excellent mechanical properties, and has various other properties. Can be improved. In addition, this composition also has the effect of improving the compatibility and dispersibility of the third component resin, which is originally poorly compatible with the polyacetal resin, expanding the range of its modification, The use of is expected.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
The dispersibility and other characteristics of the resin composition were evaluated according to the following methods. [Confirmation of compatibility and interfacial adhesiveness] Observation of the fracture surface of the molded piece as it is or after immersion treatment in a solvent of vinyl copolymer (B) or a solvent of polyacetal (A), and then observe the fracture surface with an electron microscope And the clarity of the interface, the particle dispersion form (particle shape,
Size), dispersibility of each component, interfacial adhesion, etc. according to the condition of the fracture surface were determined. The dispersibility and interfacial adhesiveness were ranked as excellent, good, and poor by combining them. [Mechanical strength of molded piece] The tensile strength and elongation were measured in accordance with the method of ASTM D638. [Surface Peeling Test] An adhesive tape was attached to the surface of the tensile test piece, and this was instantaneously peeled off under a certain condition, and the presence or absence of surface peeling of the test piece was visually judged. [Weld elongation] A test piece was formed by molding with a two-point gate mold having gates at both ends so that a weld portion was formed at the center of the tensile test piece, and the test piece was measured in accordance with the method of ASTM D638. . [Specific gravity] Cut out the center part of the tensile test piece and use ASTM D792
Was measured by an underwater displacement method.

Examples 1 to 8 Polyacetal resin (Duracon, Polyplastics Co., Ltd.) (A) and ethylene-glycidyl methacrylate copolymer (glycidyl methacrylate 6) as component (B)
%) (B-1) or the same (glycidyl methacrylate 12%) (B-
2) and isophorone diisocyanate (C)
-1) and melamine (D-1) as components (D) were mixed in the proportions shown in Table 1, and if necessary, polyethylene (PE) was further added as another resin component. The mixture was melt-kneaded at a set temperature of 190 ° C. at a screw rotation speed of 80 rpm and pelletized. Next, the pellets were molded by an injection molding machine to prepare test pieces, and the above evaluation was performed. The results are shown in Table 1.

Comparative Examples 1 to 10 For comparison, (B), (C), (D)
For the case where at least one of the components is missing,
They were mixed at the ratios shown in Table 2 and molded and evaluated in the same manner as in the above Examples. The results are shown in Table 2.

Examples 9 to 12 In the above Examples, instead of isophorone diisocyanate (C-1) as the component (C), 4,4'-diphenylmethane diisocyanate (C-2) or isophorone diisocyanate trimer (C-3 ) And melamine (D-
Dicyandiamide (D-2) or bis (2,2,6,6)
Using (tetramethyl-4-piperidyl) sebacate (D-3), a molded piece was prepared and evaluated in the same manner as in the above example.
Table 3 shows the evaluation results.

Examples 13 to 18 Polyacetal resin (Duracon Co., Ltd.) Styrene-glycidyl methacrylate copolymer (5% glycidyl methacrylate) as components (A) and (B)
(B-3) or the same (glycidyl methacrylate 10%) (B-4)
, And (C) as components isophorone diisocyanate (C-
1) and melamine (D-1) as a component (D) are mixed in the proportions shown in Table 4, and A is optionally further used as another thermoplastic resin.
Similarly, a molded piece was prepared by adding an S resin or an ABS resin and evaluated. Table 4 shows the evaluation results.

COMPARATIVE EXAMPLES 11-17 For comparison, in the above example, at least one of the components (B), (C) and (D) was omitted, and the components were mixed at the ratio shown in Table 5 and molded in the same manner. Was evaluated. Table 5 shows the results
Shown in

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[Table 4]

[0027]

[Table 5]

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 18/00-18/87 C08G 59/00-59/72 C08L 63/00-63/10 CA (STN ) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. Copolysynthesis of (A) 97 to 10% by weight of a polyacetal resin and (B) a glycidyl ester of an α, β-unsaturated acid.
Olefin and / or styrene copolymer
Coalesced, itself thermoplastic and melt processable
, Thermoplastic vinyl copolymer having an epoxy group
(C) 0.1 to 10 parts by weight of a polyisocyanate compound or a modified product thereof per 100 parts by weight of a thermoplastic resin comprising 90% by weight.
A resin composition obtained by mixing and melt-kneading 0.01 to 3 parts by weight of a compound having 1 part by weight and (D) a compound having a primary or secondary amine. (B) a thermoplastic vinyl resin having an epoxy group
The copolymer contains 50 mol% or more of styrene or olefin.
Glycidyl esters of α, β-unsaturated acids, and
Use at least one of acrylonitrile and butadiene as monomer
The resin composition according to claim 1, which is a multicomponent copolymer as a component . 3. The polyisocyanate compound (C) or a modification thereof.
Is a diisocyanate or a dimer or trimer thereof
The resin composition according to claim 1, wherein 4. A compound having a primary or secondary amine (D).
Is an amidine compound, a piperidine compound or
The resin composition according to any one of claims 1 to 3, which is a derivative of 5. The method according to claim 1, further comprising another thermoplastic resin.
The resin composition according to any one of claims 4 to 4 .