JPH0711101A - Polyacetal resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition in which the polyacetal resin has improved affinity for ingredients including an aliphatic polyether and the ingredients have improved dispersibility in the resin and which gives a molding having excellent antistat properties and a good surface. CONSTITUTION:100 pts.wt. polyacetal resin is mixed with 0.5-30 pts.wt. aliphatic polyether, 0.5-30 pts.wt. phenolic polymer having a phenol group in the main chain or the side chain, 0-10 pts.wt. hydroxylated ester of a polyhydric alcohol with a fatty acid, and 0-100 pts.wt. (in)organic filler.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyacetal resin.
A polyacetal having a particularly excellent antistatic property, good dispersibility of both components, and good surface properties and moldability, which relates to a molding resin composition containing (A) an aliphatic polyether (B). It relates to a resin composition.

[0002]

2. Description of the Related Art Polyacetal resins have mechanical properties, thermal properties, electrical properties,
It has excellent properties such as slidability and moldability, and is widely used as structural materials and mechanical parts in electric and electronic equipment, automobile parts, precision machine parts, etc. However, since polyacetal resin has a high surface resistivity,
Depending on the application, static electricity noise, adhesion of foreign matter on the surface, etc.
Problems due to electrification are likely to occur and often cause a problem depending on the application. It has been proposed to incorporate various antistatic agents in order to deal with such electrostatic damage. However, an ionic antistatic substance is not preferable because it causes discoloration of polyacetal, deterioration of thermal stability, and the like. On the other hand, aliphatic polyethers such as polyethylene glycol and fatty acid esters of polyhydric alcohols having a hydroxyl group have moderate hygroscopicity, and it is known that when blended with a polyacetal resin, conductivity and antistatic property are improved. However, unlike general thermoplastic resins, polyacetal resin has high crystallinity, mutual compatibility and dispersibility are poor, stable and uniform antistatic property is difficult to obtain, and phase separation occurs at the interface, When it is made into a product, the surface layer peels off, which is a practical problem. In particular, when a relatively large amount of aliphatic polyether or the like is added to enhance the effect, this trouble is remarkable. The object of the present invention is to improve the affinity and dispersibility of the polyacetal resin with respect to the aliphatic polyether and the like, impart an excellent antistatic effect, and provide a resin composition having a good molded article surface. To do.

[0003]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a polyacetal resin and an aliphatic polyether resin are melt-kneaded together with a specific phenolic polymer compound. Thus, they have found that the dispersibility can be improved, the surface condition of the molded article is excellent, the peeling of the surface layer can be suppressed, and the polyacetal resin can be provided with an excellent antistatic effect, and the present invention has been completed. That is, the present invention provides (A) polyacetal resin 100
Parts by weight, (B) aliphatic polyether 0.5 to 30 parts by weight,
(C) 0.5 to 30 parts by weight of a phenolic polymer compound having a phenol group in the main chain or side chain, (D) a fatty acid ester of a polyhydric alcohol having a hydroxyl group 0 to 10 parts by weight, (E) an inorganic or organic filler The polyacetal resin composition comprises 0 to 100 parts by weight.

The components used in the present invention will be described below. The component (A) polyacetal resin in the present invention is a polymer compound having an oxymethylene unit- (OCH ₂ )-as a main constituent unit, a polyoxymethylene homopolymer, or an oxymethylene group as a main repeating unit,
In addition to this, other structural units such as ethylene oxide,
It may be any of copolymers, terpolymers and block polymers containing a small amount of comonomer units such as 1,3-dioxolane and 1,4-butanediolformal, and the molecule has not only a linear structure but also a branched or crosslinked structure. It may be one or a known modified polyacetal having various modified groups introduced therein. Also, there is no particular limitation on the degree of polymerization, and those having moldability (for example, 190
Melt flow value (MFR) under load of 2160g at 1.0 ℃
~ 100)

The aliphatic polyether as the component (B) used in the present invention is a polyether having an aliphatic ether group having 2 to 4 carbon atoms as a main repeating unit, and is a homopolymer. May be a copolymer. Further, the type of the terminal group is not particularly limited, regardless of the presence or absence of a side chain, but it is preferably an -OH terminal. Examples include polyethylene glycol, polypropylene glycol, polybutylene glycol, chlorohydrin rubber and the like. These can be used in a range from relatively low molecular weight to high molecular weight, but the degree of antistatic effect tends to decrease as the molecular weight increases.
Below, it is particularly preferable to be about 400 to 10,000. The amount of the aliphatic polyether (B) compounded is 0.5 to 30 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight of the polyacetal resin. If the compounding amount of the component (B) is too small, the effects such as the antistatic property, which are the object of the present invention, cannot be sufficiently obtained, and if it is too large, the original characteristics of the polyacetal resin are lost, and neither is preferable. .

Next, the composition of the present invention is not particularly required, but when a fatty acid ester of a polyhydric alcohol having a free hydroxyl group obtained from a fatty acid and a polyhydric alcohol is blended together as the component (D), the antistatic effect is further improved. Enhanced and preferred. The fatty acid ester of a polyhydric alcohol having such a hydroxyl group (D), lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, pehenic acid, montanic acid, citric acid, oleic acid, hydroxy stearic acid and the like , A fatty acid ester alcohol having at least one free hydroxyl group and at least one ester group obtained by reaction with a polyhydric alcohol such as glycerin, pentaerythritol, diglycerin, and sorbitol. The amount of the fatty acid ester (D) of the polyhydric alcohol having a hydroxyl group is set to the polyacetal resin (A) 10
It is 10 parts by weight or less, preferably 0.1 to 5 parts by weight, based on 0 parts by weight.

In order to improve the dispersibility of each of the above components, the present invention blends a phenolic polymer compound as component (C) with the above-mentioned polyacetal resin (A) and aliphatic polyether resin (B). However, it is characterized by melt-kneading. The phenolic polymer compound used in the present invention is a polymer compound having a phenolic —OH group containing a phenol group in its main chain or side chain. Examples of the polymer compound having a phenol group in the main chain include, but are not limited to, novolac resins, resole resins and their derivatives, copolymers and hydrogenated products thereof. Further, examples of the polymer compound having a phenol group on the side chain include polyvinylphenol and the like, and homo- and copolymers of ortho-, meta- and para-vinylphenol, and other vinyl compounds. It may be a copolymer of The phenol group of the component (C) may be directly bonded to an atom constituting the main chain, or may be bonded to the main chain via another divalent organic group.
Further, it may be a phenol group having various substituents other than -OH. Examples of the substituted phenol group include groups such as chlorophenol, hydroquinone, cresol, hydroxybenzoic acid, catechol, resorcinol, salicylic acid, and 3-methylphenol. In the present invention, the presence of the phenolic polymer compound (C) means that the polyacetal resin (A) is different from the aliphatic polyether resin (B), and further a fatty acid ester of a polyhydric alcohol.
It not only improves the dispersibility of (D), improves the surface peeling of molded products and improves the surface condition of molded products, but also significantly improves the mechanical properties and suppresses excessive exudation of component (D). It has the effect of This can be confirmed by a tape peeling test for the molded article of the composition. That is, in the case of a molded product in which the component (C) does not exist, the surface of the molded product easily peels off. On the other hand, the resin composition containing the component (C) of the present invention,
In the same tape peeling test, it was confirmed that even if a relatively large amount of component (B) was added, peeling did not occur, and a stable antistatic effect was obtained. The compounding amount of these phenolic polymer compounds (C) is 100% of the polyacetal resin (A).
0.5 to 30 parts by weight, preferably 1
~ 20 parts by weight. If the blending amount of the component (C) is too small, the dispersibility of the component (B) or the component (D), which is the object of the present invention, is poor,
If it is too large, the original properties of the polyacetal resin are lost, which is not preferable.

In the present invention, the filler of the component (E) is not always an essential component, but it is excellent in conductivity, antistatic property, mechanical strength, heat resistance and dimensional stability. It can be arbitrarily mixed to obtain a molded product.
For these, a fibrous, powdery, plate-like, or hollow filler is used depending on the purpose. In particular, the compounding of a conductive filler is preferable because the antistatic effect aimed at by the present invention is further improved. The conductive filler may be a conductive, carbon black, graphite, carbon fiber, or a fibrous, powdery, or plate-like substance made of metal such as stainless steel, titanium, copper, or brass, which has high conductivity. However, it is not particularly limited. The filler (D) may be a fibrous purifying agent other than the above-mentioned conductive filler, a powdery or granular filler, or a combination of both.
Examples of the fibrous filler include glass fiber, asbestos fiber, silicon fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber and potassium titanate fiber. A particularly representative fibrous filler is glass fiber. Incidentally, a high melting point organic fibrous substance such as an aromatic polyamide resin, a fluororesin or an acrylic resin can also be used. As the powdery and granular filler, silica, quartz powder, glass beads, glass powder, glass balloon, silas balloon, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite. , Iron oxide, titanium oxide, metal oxides such as alumina, metal sulfates such as calcium sulfate, barium sulfate, carbonates such as calcium carbonate, magnesium carbonate, dolomite, other silicon carbide, silicon nitride, boron nitride, various Metal powder etc. are mentioned. Examples of the plate-like filler include mica and glass flakes. The surface of these fillers is preferably surface-treated using organic silane, organic borane, organic titanate, urethane or the like. These fillers can be used alone or in combination of two or more. The combined use of a fibrous filler, especially glass fiber or carbon fiber, with a powdery or plate-like filler is a preferable combination particularly in terms of having both mechanical strength and dimensional accuracy. The amount of the filler (E) compounded is 100 parts by weight or less based on 100 parts by weight of the polyacetal resin (A),
If the amount added is too large, the molding processability and toughness are impaired, which is not preferable.

Further, the resin composition of the present invention may contain various known additives for imparting desired properties, such as antioxidants, heat stabilizers, light resistance (weathering) stabilizers, and hydrolysis stabilizers. Additives such as stabilizers, lubricants, lubricants, nucleating agents, colorants such as dyes and pigments, release agents, plasticizers, flame retardants and the like may be added. Further, another thermoplastic resin may be further compounded within the range where the object of the present invention is not lost.

The polyacetal resin composition of the present invention can be prepared by various known methods.
It is heated and melted in the coexistence of the three components (A), (B) and (C), and
It is necessary to perform a kneading treatment for not less than a second, and other components may be simultaneously used in combination or may be added separately. Specifically, for example, polyacetal resin (A) and aliphatic polyether (B) and phenolic polymer compound (C), and if necessary, other additives are preliminarily homogenized in a mixer such as a tumbler or a Henschel mixer. After mixing into 1 axis or 2
A method of supplying the mixture to an extruder of a shaft and melt-kneading is generally used, and an open roll, a Banbury mixer, a kneader or the like may be used. It is preferable to dry each component in advance before kneading. The resin composition kneaded by these methods may be pelletized and then directly molded. The processing temperature is 5 ° C to 100 ° C higher than the melting temperature of the resin component.
The temperature is higher by 0 ° C., particularly preferably by 10 ° C. to 60 ° C. higher than the melting temperature of both mixtures. If the temperature is too high, decomposition or abnormal reaction occurs, which is not preferable. The melt-kneading time is at least 20 seconds or more and 10 minutes or less, preferably 1 to 5
Minutes.

[0011]

EFFECTS OF THE INVENTION The resin composition of the present invention, in which the aliphatic polyether (B) and the phenolic polymer (C) are blended with the polyacetal resin (A), has good dispersibility of each component and peels off the surface layer of the molded product. There are no problems such as the above, the antistatic effect is excellent, various other properties can be improved, and many applications are expected.

[0012]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
The properties of the composition were evaluated by the following methods. [Surface layer peeling test] Stick a cellophane tape on the surface of the test piece,
After peeling under constant conditions, the peeling condition of the surface layer of the molded product was visually evaluated, and those that did not peel at all were rated as ◯, and those that peeled were rated as x. [Surface resistivity] Surface resistivity (Ω) according to JIS K 6911
Was measured.

Examples 1 to 5, Comparative Examples 1 to 5 (A) Polyacetal resin (Polyplastics Co., Ltd.,
Duracon), (B) Polyethylene glycol (PEG)
Alternatively, polypropylene glycol (PPG), (C) novolak (Hoechst, Alnovol PN430) or polyvinylphenol (Maruzen Petrochemical Co., Ltd., Marca Linker M) was blended in the proportions shown in Table 1, and the mixture was mixed using a twin-screw extruder. Melt kneading was performed at a cylinder temperature of 190 ° C. to obtain pellets. Then, the pellets were injection-molded to prepare a test piece, and the above evaluation was performed. Further, for comparison, the same test evaluation was carried out when the components (B) and / or (C) among the components (A), (B) and (C) were not blended. The results are shown in Table 1.

Examples 6 to 12, Comparative Examples 6 to 8 In addition to the above Examples and Comparative Examples, as shown in Table 2 and Table 3, (D) glycerin monostearate or glycerin monolaurate was added. Similarly tested and evaluated. The results are shown in Tables 2 and 3.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

Claims (1)

[Claims] 1. (A) 100 parts by weight of a polyacetal resin, (B) 0.5 to 30 parts by weight of an aliphatic polyether, (C) 0.5 to 30 parts by weight of a phenolic polymer compound having a phenol group in a main chain or a side chain. , (D) Fatty acid ester of polyhydric alcohol having hydroxyl group
A polyacetal resin composition comprising 0 to 10 parts by weight, (E) an inorganic or organic filler, and 0 to 100 parts by weight.