JPS5818383B2 - polyacetal polyacetal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyacetal resin composition reinforced with carbon fibers and a method for producing the same.

Carbon fibers are used as a mixture in many resins because, by adding them to the resin, they can improve the mechanical properties, heat resistance, electrical properties, sliding properties, etc. of the resin.

In particular, when added to polyacetal resin, its wear resistance, limit Pv value, thermal conductivity, and electrical conductivity are significantly improved, making it an extremely excellent material for applications such as bearings.

However, when polyacetal resin and carbon fiber are simply kneaded, the strength thereof is not improved compared to when polyacetal resin alone is used, and it cannot be said that the strength of the carbon fiber itself is effectively utilized.

The present inventors have considered forming some kind of chemical bond at the interface between the polyacetal resin and the carbon fibers in order to increase the strength of the composition made of the polyacetal resin and the carbon fibers.

However, in this case, even if the method used to bond polyolefin etc. and inorganic fillers is applied as is, satisfactory results are often not obtained because polyacetal resin itself has properties that make it difficult to undergo effective modification. I couldn't.

As a result of more detailed studies, the present inventors found that unsaturated polyester exhibits a very unique effect in bonding polyacetal resin and carbon fiber, and that a radical polymerization initiator is added together with unsaturated polyester. The present invention was completed based on the discovery that the effect can be further enhanced.

That is, the present invention relates to a carbon fiber-reinforced polyacetal resin composition comprising a polyacecool resin, carbon fibers and unsaturated polyester, and optionally containing a radical polymerization initiator, and a method for producing the same.

Furthermore, the manufacturing method is a method in which polyacetal resin, carbon fiber and unsaturated polyester, or a product to which a radical polymerization initiator is added as necessary, are kneaded substantially simultaneously at a temperature equal to or higher than the melting point of the polyacetal resin.

The polyacetal resin used in the present invention is an oxymethylene homopolymer or a copolymer with a cyclic ether or the like mainly containing an oxymethylene group, and the present invention exhibits excellent characteristics particularly when an oxymethylene homopolymer is used.

The carbon fiber used in the present invention is not particularly limited, and may be manufactured by any manufacturing method.

Although the amount added is not particularly limited, it is preferably added in an amount of 5 to 150 parts by weight per 100 parts by weight of the polyacetal resin from the viewpoint of reinforcing effect, moldability, etc.

Particularly preferred is 10 to 100 parts by weight.

Further, carbon fibers whose surfaces have been treated with an oxidizing agent or the like may be used.

The unsaturated polyester used in the present invention includes unsaturated dicarboxylic acid or a combination thereof with a saturated dicarboxylic acid, saturated or unsaturated monocarboxylic acid, and polyhydric alcohol or a combination thereof with a monohydric alcohol. A product obtained by esterification reaction of: whose degree of polymerization is 5 to 100, preferably 10
~50.

The optimum amount of unsaturated polyester added varies depending on the amount of carbon fiber added, but is preferably 0.1 to 20 parts by weight per 100 parts by weight of the polyacetal resin.

Particularly preferred is 0.5 to io parts by weight.

Although it is not necessary to use a radical polymerization initiator in the present invention, even better effects can be obtained by using it in combination with an unsaturated polyester.

Examples of radical polymerization initiators include organic peroxides, and azobisnitriles and the like may also be used.

The organic peroxide preferably has a relatively high decomposition temperature.

The amount added is 5 parts by weight or more per 100 parts by weight of the polyacetal resin.

The amount is preferably from 0.05 to 1 part by weight.

In the present invention, even more excellent effects can be expected by using the unsaturated polyester in combination with other reactive unsaturated compounds.

In particular, styrene, diallyl phthalate, etc., which are often added as crosslinking agents to unsaturated polyesters, acrylic esters, acrylic amide, methacrylic ester, methacrylic amide, fatty acid vinyl, vinyl silane, acrylic silane, divinylbenzene, Even better effects can be obtained by using in combination ethylenically unsaturated compounds such as acrylonitrile and dicyclopentadiene, or urea and maleimide.

The composition of the present invention may further contain various additives as required.

For example, stabilizers, lubricants, solid lubricants such as graphite or molybdenum disulfide, flame retardants, various fillers, and reinforcing agents may be added.

The composition of the present invention can be prepared by adding polyacecool resin, carbon fiber and unsaturated polyester, or adding a radical polymerization initiator to these, and furthermore, in some cases, using a reactive unsaturated compound together with a kneading machine such as an extruder or a kneader. It is preferable to knead them substantially simultaneously.

Here, "substantially simultaneously" means that the reaction occurs while the composition is kneaded and dispersed in a state in which the above-mentioned components are present simultaneously, or at the same time as the dispersion is completed.

Examples of the most preferred methods for obtaining the compositions of the present invention include the following methods.

i.e. polyacetal resin (powder or pellets)
, carbon fiber and unsaturated polyester, or a radical polymerization initiator is added thereto, thoroughly mixed at room temperature using a Henschel mixer or ribbon blender, etc., and then mixed using an extruder at a temperature higher than the melting point of the polyacetal resin. The composition of the present invention can be obtained by kneading at temperature and reacting simultaneously.

At this time, a kneader, intensive mixer, etc. may be used instead of an extruder, but it is preferable to use an extruder from the viewpoint of blocking oxygen.

The composition of the present invention can be molded by ordinary molding methods such as injection molding and extrusion molding, and can be used in applications other than those for which general polyacetal resins are used, such as high strength, high elasticity, sliding properties, electrical properties, etc. It can be used in fields where it is required.

Examples are shown below, but the present invention is not limited by the following examples.

Examples 1 to 9, Comparative Examples 1 to 2 Polyacetal resin, carbon fiber, and unsaturated polyester, or a product containing a radical polymerization initiator or other unsaturated compound added thereto, were mixed in the formulation shown in Table 1 using a Henschel mixer. Mix thoroughly at room temperature, and transfer the mixture to a single-screw vent type extruder (40 mm φ, L/D = 28, cylinder temperature 20 mm).
0° C.).

The obtained pellet was molded into a tensile test piece using an injection molding machine, and the tensile strength was measured according to the measurement method of ASTM D638.

The results are shown in Table 1. Also, as a comparative example,
Table 1 shows the tensile strengths of the polyacetal resin and carbon fibers kneaded in the same manner as above and the polyacetal resin alone.

The resins, carbon fibers, unsaturated polyesters, and others used in the examples are as follows.

Polyacetal resin nioxymethylene homopolymer, MI = 13 Carbon fiber 1: Average fiber length 3 mm Carbon fiber 2: Average fiber length 0.1 ml
) Unsaturated polyester 1: Unsaturated polyester consisting of phthalic anhydride, maleic anhydride and propylene glycol, average degree of polymerization approximately 25. Unsaturated polyester 2: Unsaturated polyester consisting of terephthalic acid, maleic anhydride and diethylene glycol, average degree of polymerization approximately 25. 20 Radical polymerization initiator 1: 2,5-dimethyl-2,5-di(t-butylperoxy)hexane Radical polymerization initiator 2 Dicumyl peroxide Styrene acrylamide Methyl methacrylate As shown above, the present invention Carbon fiber-reinforced polyacetal resin compositions have much higher strength than compositions in which carbon fibers are simply added to polyacetal resin, and conventional polyacetal resins alone or in compositions in which carbon fibers are added cannot be used. It is a resin composition that can be used in fields where it is not possible.

Claims (1)

[Claims] 1. 100 parts by weight of polyacetal resin, 5 to 1 part of carbon fiber
50 parts by weight, 0.1 to 20 parts by weight of unsaturated polyester,
and a carbon fiber reinforced polyacetal resin composition comprising 0 to 5 parts by weight of a radical polymerization initiator. 2 Ioo parts by weight of polyacetal resin, 5 to 1 parts of carbon fiber
50 parts by weight of an unsaturated polyester, 0.1 to 20 parts by weight of an unsaturated polyester, and 0 to 5 parts by weight of a radical polymerization initiator are substantially simultaneously kneaded at a temperature equal to or higher than the melting point of the polyacetal. Method of manufacturing the composition.