JP3135408B2 - Polyacetal resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition obtained by blending a specific modified vinyl copolymer with a polyacetal resin and melt-kneading the resin, and has excellent compatibility, dispersibility and interfacial adhesion between the resins, and a polyacetal resin. It is intended to provide a composition in which various disadvantages are improved by compensating for the respective disadvantages caused by the vinyl resin alone.

[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 properties, 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, this resin also has problems that require improvement in weather resistance, acid resistance, molding shrinkage, adhesiveness, etc., depending on the purpose of use.
In addition, vinyl resins are excellent in weather resistance, acid resistance, molding shrinkage, etc., but generally have a low softening point, and generally have a limit in mechanical properties. It is common practice to compensate for the disadvantage by blending another resin having the property of compensating for 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, the adhesion between the two phases is insufficient, and the phase at the interface is poor. When separation occurs and it is a molded product,
In some cases, surface layer peeling may occur, and it is extremely difficult to modify such a resin by a compounding means. The blending with general vinyl resins is no exception, and the adhesion at the interface of both phases is insufficient.
Phase separation occurs at the interface, and when formed into a molded product, surface layer peeling occurs, which causes a reduction in mechanical properties, and thus poses a practical problem. From this viewpoint, the present invention searches for and examines a modified vinyl resin having good compatibility, dispersibility, and interfacial adhesiveness with the polyacetal resin, and by mixing the modified vinyl resin, keeps a uniform and good dispersion form, thereby maintaining mechanical properties. It is an object of the present invention to provide a molding resin composition in which various properties such as surface condition and the like are modified and improved.

[0003]

In order to achieve the above object, the present inventors have made intensive studies on the improvement of compatibility, dispersibility, and interfacial adhesion between a polyacetal resin and a vinyl resin, and as a result, a specific modified vinyl resin has been obtained. By discovering that the copolymer satisfies this property, blending this copolymer and melt-kneading it, the excellent properties inherent in both resins are maintained, and when both are used alone, Have been found to improve the disadvantages of the present invention, and have arrived at the present invention. That is, the present invention relates to (A) 97 to 5 parts by weight of a polyacetal resin and (B) 2 to 40 parts of a monomer compound represented by the following general formula (1).
3 to 95 parts by weight of modified vinyl copolymer introduced by weight

[0004]

Embedded image

[0005] A resin composition comprising

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. The degree of polymerization is not particularly limited, and it is sufficient that the polymer has moldability (for example, a melt flow value (MFR) at 190 ° C. under a load of 2160 g is 1.0 to 100).

Next, the modified vinyl copolymer (B) to be blended with the polyacetal resin (A) in the present invention is mainly composed of a vinyl structural unit and modified with a monomer represented by the general formula (1). It is a copolymer. The monomer compound represented by the general formula (1) constituting the modified vinyl copolymer (B) may constitute the main chain of the vinyl copolymer (B), and may be bonded to a side chain. It may be. The preparation of the modified olefin-based copolymer (B) is not particularly limited.Along with the vinyl-based polymer or monomer, at least one of the monomer compounds represented by the above general formula (1) may be prepared by using a suitable catalyst or polymerization initiator. By reacting with heat in the presence of Examples of the monomer compound of the general formula (1) used for modifying such a vinyl-based polymer include, for example, N
-Phenylmaleimide, N- (o-tolyl) maleimide, N- (m-tolyl) maleimide, N- (p-tolyl) maleimide, N- (o-bisphenyl) maleimide, N- (p-bisphenyl) maleimide , N- (o-
Chlorophenyl) maleimide, N- (p-chlorophenyl) maleimide, N- (o-hydroxyphenyl) maleimide, N- (p-hydroxyphenyl) maleimide,
N- (p-methoxyphenyl) maleimide, N- (p-
Ethoxyphenyl) maleimide, N- (p-carboxyphenyl) maleimide, N- (p-acetylphenyl)
Maleimide, N- (p-acetoxyphenyl) maleimide, N- (p-acetamidophenyl) maleimide,
N, N'-phenylene bismaleimide, N, N'-diphenylene methane bismaleimide and the like. Further, the maleimide group of the above compound may be methylmaleimide, dimethylmaleimide, phenylmaleimide, or diphenylmaleimide. Preferably N-phenylmaleimide, N
-(O-hydroxyphenyl) maleimide, N- (p-
(Hydroxyphenyl) maleimide, N- (p-methoxyphenyl) maleimide, N- (tolyl) maleimide, N
-(P-carboxyphenyl) maleimide, more preferably N-phenylmaleimide and N- (o-hydroxyphenyl) maleimide.

One of the preferred modified vinyl copolymers (B) used in the present invention is a modified styrene copolymer. 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).
Any of those obtained by suspension polymerization, emulsion polymerization and the like can be used. Further, the modified styrene-based copolymer of the present invention may be a copolymer mainly composed of styrene and copolymerized with a reactive monomer such as another vinyl compound or diene-based compound, or a rubber component is introduced. In particular, styrene, α-methylstyrene, or a copolymer containing these as a main component, such as acrylic acid ester, methacrylic acid ester, acrylonitrile, butadiene, chlorinated ethylene and the like are preferably used.
One of the preferred modified vinyl copolymers (B) used in the present invention is a modified acrylic copolymer. Such modified acrylic copolymers include acrylic acid and acrylic acid esters (for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, n-acrylic acid). Hexyl, n-octyl acrylate, etc.), methacrylic acid and methacrylic acid esters (for example, methyl methacrylate, ethyl methacrylate, methacrylic acid-n-
Propyl, isopropyl methacrylate, methacrylic acid
n-butyl, isobutyl methacrylate, methacrylic acid-
n-amyl, n-octyl methacrylate, etc.) and a monomer compound represented by the general formula (1). Other vinyl compounds such as styrene and acrylonitrile containing these acrylic monomers as main components, butadiene And a copolymer using a diene compound such as isoprene as a comonomer. Of these, a methyl methacrylate polymer or a copolymer containing methyl methacrylate as a main component and containing another acrylate or another methacrylate, acrylic acid, methacrylic acid, styrene, acrylonitrile, or the like is preferably used. Particularly preferred is a polymer containing, as a monomer, an ester of methacrylic acid and an aliphatic alcohol having 1 to 8 carbon atoms. The molecular weight is not particularly limited, but is preferably a low-viscosity linear one from the viewpoint of processability.
Further, one of the other preferable ones belonging to the modified vinyl copolymer (B) is a modified olefin copolymer. Such modified olefin copolymers are also ethylene, propylene, butene-1,3-methylbutene-1,4-methylpentene-
A copolymer of one or more ethylene and α-olefin monomers such as 1 and a monomer compound represented by the general formula (1). Esters, acrylic acid, methacrylic acid and derivatives thereof (eg, methyl acrylate, methyl methacrylate, dimethylaminoethyl acrylamide, etc.), maleic acid / maleic anhydride and derivatives thereof (eg, dimethyl maleate, diethyl maleate, etc.), butadiene And a copolymer containing a diene such as isoprene. 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.

The modified vinyl copolymer (B) used in the present invention
Is a vinyl monomer as described above and the general formula
Although it can be prepared by directly copolymerizing the monomer compound represented by the formula (1), a pre-polymerized vinyl polymer or copolymer and the monomer compound represented by the general formula (1) can be prepared by using a suitable catalyst. Alternatively, it can also be prepared by heat-melt kneading treatment in the presence of a polymerization initiator. Such a modified vinyl copolymer (B) may be any of a copolymer, a terpolymer and a block copolymer further containing a small amount of a crosslinking agent or another modifier, and the molecule has not only a linear but also a branched or crosslinked structure. The degree of polymerization is not particularly limited, and any thermoplastic resin having melt processability may be used. The amount of the compound of the formula (1) constituting the modified vinyl copolymer (B) is 2 to 40% by weight . If the content of the general formula (1) is too large, the characteristics (cost, physical properties, etc.) of the vinyl resin are lost, and if the content is too small, the effect of compatibility, dispersibility, adhesion, etc. with the polyacetal resin is obtained. Is not preferred. The compounding amount of the modified vinyl copolymer (B) is 3 to 95 parts by weight, preferably 5 to 9 parts by weight, based on 100 parts by weight in total with the polyacetal resin (A).
0 parts by weight. 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.

The resin composition of the present invention has good compatibility and dispersibility between the polyacetal resin (A) and the modified vinyl copolymer (B), and the component (A) or the component (B) is a very fine particle. It is evenly dispersed and the interface has improved adhesion. This can be confirmed by observing the fracture surface of the composition molded article with an electron microscope. That is, in the case of a molded article of a composition of a polyacetal resin and another general vinyl-based resin, 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. It was confirmed as large particles or as a layered two-phase separation structure, and it was recognized that poor adhesion at the interface caused the fracture. When immersed in a reagent in which one resin dissolves,
The resin phase is eluted and is recognized from the fact that cavities are formed. On the other hand, in the resin composition containing the specific modified vinyl copolymer (B) of the present invention, the interface between the two resins is hardly discernable or very fine in the same observation or treatment. It was confirmed that the particles were dispersed as particles, and it was suggested that the interface was not the cause of breakage, indicating that the specific resin composition of the present invention was excellent in dispersibility and interfacial adhesion.

Further, the modified vinyl copolymer used in the present invention
(B), as described above, not only the component (B) itself has good compatibility with the polyacetal resin, but also the third component (B) has poor compatibility and dispersibility with the polyacetal resin due to the presence of the component (B). The resin component (C), for example, also has an advantage of improving the compatibility and dispersibility of a general vinyl resin or polyester resin, polyamide resin, polyurethane resin, etc. It is expected that the possibility of resin blending with other resins will be expanded, and that the possibility of modification will be greatly enhanced. From this point of view, the composition of the present invention can further contain many other thermoplastic resins (C) as the third component, and as such a resin as the third component, for example, polyethylene, polypropylene, ethylene propylene rubber, ethylene -Vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, olefinic resin such as propylene-maleic anhydride copolymer, polyethylene glycol, polyoxyalkylene glycol such as polypropylene glycol, polystyrene, styrene-butadiene copolymer, Styrene-acrylonitrile copolymers, styrene resins such as ABS resins, polyurethane resins, polyamide resins, polyester resins and the like are particularly preferred. The blending amount of the thermoplastic resin (C) is 100 per 100 parts by weight of the total of the components (A) and (B).
It is at most 75 parts by weight, preferably at most 75 parts 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 antistatic agents, antioxidants, heat stabilizers, weather (light) stabilizers, hydrolysis stabilizers, reinforcing agents, fillers and the like can be added.

The composition of the present invention can be prepared by various known methods, but it is necessary to heat and melt the mixture in the presence of at least two components (A) and (B) and to knead it for 20 seconds or more. Yes, other components may be simultaneously used together, or may be added separately. Specifically, for example, after the polyacetal resin (A) and the modified vinyl copolymer (B) and other additives are uniformly mixed in advance by a mixer such as a tumbler or a Henschel mixer, if necessary, a uniaxial or A method of supplying the mixture to a twin-screw extruder and kneading the mixture is generally used, 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.

[0014]

The resin composition comprising the polyacetal resin (A) of the present invention and a specific modified vinyl copolymer (B) is blended.
Excellent compatibility and dispersibility between resin components, no problems due to poor dispersion such as surface layer peeling of molded products, excellent mechanical properties,
Various other properties can be improved. This composition also has the effect of improving the compatibility of the third component resin, which is inherently incompatible with the polyacetal resin, expanding the range of its modification, and is expected to find many uses.

[0015]

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 adhesion] The fracture surface of the molded piece was observed as it was or after immersion in the solvent of the copolymer (B) or the solvent of polyacetal. Then, the interfacial adhesion and the like of each component were determined according to the particle dispersion form (particle shape and size) and the state of the fracture surface. 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.

The modified vinyl copolymer (B) used in this example was prepared by the following method. [Preparation of Modified Olefin-Based Copolymer (B-1-6)] An olefin-based polymer represented by B-1 to B-6 and a monomer of the formula (1) are reacted with a radical polymerization initiator (2,5-dimethyl-2, Five
The mixture was heated, melted and kneaded in the presence of -ditertiary butyl peroxyhexine-3) and reacted to obtain a modified olefin-based copolymer (B-1 to 6). The copolymer composition of the resulting modified olefin copolymer (B) is as shown below. [Preparation of Modified Styrene-Based Copolymer (B-7 to 12)] Styrene, a monomer of the formula (1) shown below, and optionally other monomers are added in the presence of a radical catalyst (azobisisobutyronitrile). It was prepared by heat polymerization. The copolymer composition of the obtained styrenic copolymers B-7 to B-12 is as shown below. [Preparation of Modified Acrylic Copolymer (B-13)] Methyl methacrylate and a monomer represented by the following formula (1) were polymerized by heating in the presence of a radical catalyst (azobisisobutyronitrile). The obtained acrylic copolymer B-13
Is as shown below. B-1: polypropylene: N-phenylmaleimide = 9
5: 5 (% by weight) B-2; polypropylene: N-phenylmaleimide = 9
8: 2 (% by weight) B-3; polypropylene: N-phenylmaleimide = 7
0:30 (% by weight) B-4; Polypropylene: N- (p-hydroxyphenyl) maleimide = 95: 5 (% by weight) B-5; Polyethylene: N-phenylmaleimide = 95:
5-6 (weight%) B-6; ethylene-ethyl acrylate: N-phenylmaleimide = 95: 5 (weight%) B-7; styrene: N-phenylmaleimide = 95: 5
(Weight%) B-8; styrene: N-phenylmaleimide = 98: 2
(Weight%) B-9; styrene: N-phenylmaleimide = 70: 30
(Weight%) B-10; styrene: N-phenylmaleimide: acrylonitrile = 70: 5: 25 (weight%) B-11; styrene: N-phenylmaleimide: butadiene = 70: 5: 25 (weight%) B- 12; styrene: N-phenylmaleimide: butadiene: acrylonitrile = 55: 5: 20: 20 (% by weight) B-13; methyl methacrylate: N-phenylmaleimide = 95: 5 (% by weight) Examples 1 to 8 Polyacetal resin (Polyplastics Co., Ltd., Duracon) and the modified olefin copolymer (B-1)
6) were mixed at the ratios shown in Tables 1 and 2 and the screw rotation speed was 80 at a set temperature of 190 ° C. using a twin-screw extruder with an inner diameter of 30 mm.
The mixture was melt-kneaded at 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 Tables 1 and 2.

Comparative Examples 1 to 7 For comparison, a polyacetal resin alone, or a polyacetal resin and an olefinic thermoplastic resin (C) which does not belong to the modified olefinic copolymer (B) of the present invention were mixed in the proportions shown in the table. Then, it was molded and evaluated in the same manner as in the above examples.
The results are shown in Tables 1 and 2.

Examples 9 and 10 The polycetal resin and modified olefin copolymer (B
-3) and another olefin-based resin (C) were mixed at the ratio shown in Table 3, and a test piece was prepared and evaluated in the same manner as in the above example. The results are shown in Table 3.

Examples 11 to 18 The polyacetal resin and the modified styrenic copolymer (B-7 to 12) were mixed in the proportions shown in Tables 4 and 5, and molded and evaluated in the same manner as in the above examples. Did. Table 4 shows the results.
It is shown in FIG.

Comparative Examples 8 to 14 For comparison, the styrenic thermoplastic resin (C) which does not belong to the styrenic copolymer (B) of the present invention alone, the polyacetal resin and the styrenic thermoplastic resin (C) are shown in Table 1. And then molded and evaluated in the same manner as in the above examples.
The results are shown in Tables 4 and 5.

Examples 19 to 21 The polyacetal resin and a styrene copolymer (B-
9) and further another styrene resin (C) were mixed at the ratio shown in Table 6, and a test piece was prepared in the same manner and evaluated. The results are shown in Table 6.

Example 22 and Comparative Example 15 The polyacetal resin and the acrylic copolymer (B-13) were mixed at the ratio shown in Table 7, and molded and evaluated in the same manner as in Example 1. The results are shown in Table 7.

For comparison, polymethyl methacrylate (PMMA) (C) which does not belong to the acrylic (co) polymer (B) of the present invention was mixed at the ratio shown in Table 7, and
It was molded and evaluated in the same manner as in the above. The results are shown in Table 7. The modified vinyl copolymer (B-1 to B-1)
3) The melt index (MI; measured at 190 ° C)
It is as follows. B-1; 3.4 B-2 ; 4.5 B-3; 2.3 B-4; 9.6 B-5; 3.7 B-6; 12.4 B-7; 8.1 B -8; 7.9 B-9; 6.5 B-10; 3.3 B-11; 2.8 B-12; 3.4 B-13; 11.5 Also details of other resins used Is as follows. PP (polypropylene); Sumitomo Noblen (Sumitomo Chemical Co., Ltd.)
Manufactured work (Ltd.)) EEA (ethylene - ethyl acrylate copolymer (75-
NUC copolymer (Nihon Unicar Co., Ltd.)
Ltd.) PS (polystyrene); Styron (Asahi Chemical Industry Co., Ltd.
AS ) (styrene-acrylonitrile copolymer (75-25 wt.
%)); Sebian N (manufactured by Daicel Chemical Industries, Ltd.) SB (styrene-butadiene copolymer (80-20 wt. %)
%)); Asaflex (produced by Asahi Kasei Corporation) ABS (styrene-acrylonitrile-butadiene copolymer )
Coalescence (60-20-20wt% )); Sebian V (Daicel Chemical Co., Ltd. )
Industrial Co., Ltd.)

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

[0028]

[Table 5]

[0029]

[Table 6]

[0030]

[Table 7]

Claims (6)

(57) [Claims] 1. A monomer compound represented by (A) polyacetal resin 97-5 parts by weight (B) the following general formula (1) 2-40
3 to 95 parts by weight of a modified vinyl copolymer introduced by weight A resin composition comprising: 2. The resin composition according to claim 1, wherein both R ₁ and R ₂ of the monomer compound represented by the general formula (1) in the component (B) are hydrogen. 3. A modified vinyl copolymer (B) having the general formula
The resin composition according to claim 1, which is a copolymer of the monomer compound represented by (1) and at least one of styrene, olefin, and acrylic monomers. 4. A modified vinyl copolymer (B) comprising styrene or olefin as a main component, a monomer compound represented by the general formula (1), and acrylonitrile, butadiene, acrylic acid or methacrylic acid and their aliphatic acids. 3. A multi-component copolymer with at least one ester.
The resin composition as described in the above. 5. The modified vinyl copolymer (B) is a copolymer obtained by adding a monomer compound represented by the general formula (1) to a vinyl (co) polymer and subjecting it to a heat treatment. 3. The resin composition according to 1 or 2. 6. The resin composition according to claim 1, further comprising another thermoplastic resin (C).