JP3086289B2 - Polyacetal resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyacetal resin obtained by blending a modified polyacetal copolymer having a functional group such as a nitrile group, a carboxyl group, a carboxylic ester group or an amide group in a side chain with a polyacetal resin. And a polyacetal resin composition having improved compatibility.

[0002]

2. Description of the Related Art As is well known, polyacetal is widely used as an engineering plastic having excellent mechanical properties, electrical properties, chemical resistance and heat resistance. However, on the other hand, polyacetal has a very low affinity for other substances. Therefore, various problems occur when attempting modification by blending with other materials, or painting, dyeing, and the like. For example, when blending an elastomer, etc. for the purpose of improving impact resistance, etc., satisfactory impact characteristics cannot be improved due to poor affinity and compatibility with the mating material, and surface peeling occurs, resulting in molded products. May significantly impair the appearance. or,
Further, additives such as stabilizers and lubricants added for the purpose of modification may exude. Further, in many cases, sufficient adhesion cannot be obtained with respect to painting, dyeing, bonding and the like. In order to overcome such drawbacks of polyacetal, it is considered effective to add a suitable compatibilizer thereto. However, heretofore, there have been few successful examples of compatibilizers for improving sufficient affinity and compatibility with polyacetal and other substances. An object of the present invention is to solve the drawbacks of such general polyacetal resins, and to provide a resin composition having improved affinity, compatibility, adhesion, and the like with other thermoplastic resins and other additives. I do.

[0003]

Means for Solving the Problems The present inventors have made extensive studies to achieve the above object, and as a result, have found that a polyacetal resin has a nitrile group, a carboxylic acid group, a carboxylic acid, an ester group, an amide group on a side chain. The purpose has been achieved by blending a modified polyacetal copolymer having a functional group consisting of groups. That is, the present invention relates to (A) 20 to 99% by weight of polyacetal resin (based on (A) + (B)) and (B) a unit represented by the following general formula (1) in the main chain.
80-1 modified polyacetal copolymer containing 0.1-50% by weight
The present invention relates to a polyacetal resin composition comprising% by weight (based on (A) + (B)).

[0004]

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Hereinafter, the components of the composition of the present invention will be described.

The polyacetal resin of the component (A) used in the present invention is a polymer compound having an oxymethylene group (—CH ₂ O—) as a main structural unit, and is a known polyoxymethylene homopolymer or oxymethylene. It may be any of copolymers, terpolymers, and block copolymers containing a small amount of other structural units other than the group, for example, an oxyethylene group (—CH ₂ CH ₂ O—). And the terminal is not particularly limited. The degree of polymerization, branching, and crosslinking are not particularly limited, and those having melt processability (for example, a melt flow value (MRF) under a load of 2160 g at 190 ° C. of 1.5
To 70) (however, (A) does not overlap with the following modified polyacetal copolymer (B)).

Next, the modified polyacetal copolymer of the component (B) of the present invention is a copolymer containing a unit of the formula (1) in the main chain, which is disclosed in another application filed by the present inventors (Japanese Patent Application No. 3-180947). )) Are produced by the following polymerization method as detailed in (A) 99.9 to 30% by weight of trioxane (b) 0.1 to 50% by weight of a cyclic ether or cyclic formal having a functional group represented by the following general formula (2)

[0008]

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(C) 0 to 20% by weight of a cyclic ether or cyclic formal represented by the following general formula (3):

[0010]

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It is obtained by copolymerizing a monomer component consisting of a cation-active catalyst.

The copolymerizable monomer having a functional group of the component (b) used herein has a structure of a ring moiety, a functional group (general formula)
X in (2)) and its bond (R ^{2 in} general formula (2)) can be divided into three parts.

Particularly preferred examples of the ring moiety include a 1,3-dioxolane ring (in the general formula (2), p =
1, i = 1, j = 0), 1,3-propylene glycol formal ring (same as above, p = 1, i + j = 2), 1,4-butanediol formal ring (same as above, p = 1, i + j = 3), 1,
3,5-dioxepane ring (p = 2, i = 1, j =
0), an ethylene oxide ring (same as above, p = 0, i = 1, j =
0) and the like. Examples of the functional group X include a nitrile group, a carboxylic acid group, a carboxylic acid ester group, and an amide group. Particularly, a nitrile group, a carboxylic acid group, and a methyl ester group and an ethyl ester group thereof are preferable. The bond (R ^{2 in the} general formula (2)) is a divalent ether group or an alkylene group having 1 to 20 carbon atoms, and a divalent ether group having an oxygen atom enhances the compatibility of the copolymer. Preferred above. Preferred examples of the divalent ether group having an oxygen atom include a 2-oxabutylene group and a 2-oxahexylene group.

As the comonomer having a functional group of component (b), those having a structure of any combination of these three parts can be used. The cyclic ether or cyclic formal of the component (c) is not necessarily required, but is preferably added. Specific examples of component (c) include ethylene oxide, 1,3-dioxolan, 1,3,5-dioxepane,
Preferred examples include 1,3-propylene glycol formal, 1,4-butanediol formal, diethylene glycol formal, and triethylene glycol formal. As the polymerization catalyst, a cationic active catalyst generally used as a polymerization catalyst for trioxane is used. In the copolymerization reaction, a chain transfer agent can be used in order to obtain a copolymer having a desired molecular weight. As such a chain transfer agent, a molecular weight regulator generally used for copolymerization of trioxane is effectively used, and examples thereof include low molecular weight acetal compounds such as methylal, alcohols, and acid anhydrides.

The modified polyacetal copolymer as the component (B) can be produced by the same equipment and method as in the conventionally known copolymerization of trioxane. That is, both a batch type and a continuous type are possible. The reaction system after completion of the polymerization was ammonia, triethylamine, or tri-n.
Amines such as -butylamine and triethanolamine,
Or an alkali metal, alkaline earth metal hydroxide,
Add or mix other known catalyst deactivators, or
It is preferable to neutralize and deactivate the polymerization catalyst by adding and treating a solution containing these deactivators. On this occasion,
In the case where the produced polymer is in a large lump, it is naturally preferable to pulverize it once after the polymerization and to treat it.

The modified polyacetal copolymer (B) thus obtained is preferably washed and dried, and then subjected to a stabilization treatment by a method according to a general trioxane copolymer. The modified polyacetal copolymer (B) having a functional group used in the present invention has a unit (1) having a functional group.
It is introduced by copolymerization of 0.1 to 50% by weight, and is preferably a copolymer containing 0.5 to 30% by weight of the unit of the formula (1). The remaining constituent units are oxymethylene group (-CH ₂ O-), also other component units, for example, oxyethylene group (-CH ₂ CH ₂ O-) and the like is a copolymer which is further introduced Is also good. The content of the unit (1) in the modified polyacetal copolymer (B) having such a constitution is as follows:
The monomers (a), (b),
It is adjusted by changing the ratio of (c) and copolymerizing. If the number of units of the formula (1) in the modified polyacetal copolymer (B) is too small, it is not possible to obtain an improvement in affinity with other substances of the polyacetal resin composition containing the same, which is the object of the present invention, and If it is excessively large, the affinity for the polyacetal resin (A) is rather deteriorated, and the physical properties of the polyacetal resin (A) are adversely affected.
Further, the modified polyacetal copolymer used in the present invention (B)
Has a molecular weight of 1,000 to 300,000, preferably 2,000.
~ 100,000.

The mixing ratio of the polyacetal resin (A) and the modified polyacetal copolymer (B) in the polyacetal resin composition of the present invention is such that (B) is 1 to 80% by weight based on (A) + (B). , Preferably 3 to 70% by weight. The blending amount of the component (B) is arbitrarily selected depending on the amount of the unit (1) introduced in the component (B), the physical properties of the target composition, and the like. If the amount is too small, the effect of improving the affinity of the polyacetal resin composition intended for the present invention with other substances is small, and if the amount is too large, the inherent characteristics of the polyacetal resin are lost, which is not preferable. In general, the blending amount of the modified polyacetal copolymer (B) is preferably relatively small when the content of the unit (1) in the component (B) is large, and the degree of polymerization (viscosity) may be low. . When the content of the unit of the formula (1) is small, it is preferable to add a large amount.

Further, the composition of the present invention may be blended with various known additives in order to improve its physical properties according to the intended use. Examples of additives include various stabilizers such as antioxidants, heat stabilizers, and weather (light) stabilizers, coloring agents,
Lubricants, mold release agents, nucleating agents, organic polymer modifiers, and fibrous, powdery, and plate-like fillers such as inorganic, organic, and metallic materials can be used, and one or more of these can be used in combination.

The composition of the present invention is prepared by melt-kneading the components (A) and (B). Such processing is generally suitable using a single or twin screw extruder. The kneading temperature is generally between 180 and 270 ° C. still,
Other substances to be added to the composition of the present invention include (A)
It may be added simultaneously with the preparation of the composition (B), or may be separately added. Further, the resin composition according to the present invention, extrusion molding, injection molding, compression molding, vacuum molding, blow molding,
It can be formed by any of foam molding.

[0020]

The composition of the present invention, in which a specific modified polyacetal copolymer is blended with a polyacetal resin, has improved affinity and compatibility with other substances as compared with a general polyacetal resin, and can be used with other resins. Polymer alloys and improved adhesiveness, paintability, etc., and are expected to be used in many applications.

[0021]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Production Example (Modified polyacetal copolymer (B)
As shown in Table 1, (a) trioxane, (b) the following Note-1
Was added to the copolymer monomer shown in (1) and, in some cases, dioxolane (c) at 80 ° C. with stirring, and boron trifluoride dibutyl etherate was added as a polymerization catalyst, and polymerization was carried out for a predetermined time. Next, the polymer was pulverized, the remaining polymerization catalyst was deactivated with a 0.1% aqueous solution of triethylamine, and then washed and dried to obtain a copolymer. The molecular weight is a weight average molecular weight measured by gel permeation chromatography using hexafluoroisopropanol as a solvent, the content of the functional group was measured by proton NMR,
It is shown by weight% of the unit of formula (1) in the polymer chain. Table 1 shows the properties of the modified polyacetal copolymers (B-1 to 7) thus obtained.

[0023]

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[0024]

[Table 1]

Examples 1 to 7 (A) Polyacetal copolymer (Duracon M90 manufactured by Polyplastics Co., Ltd.) and (B) prepared in the above-mentioned production example
The modified polyacetal copolymers (B-1 to B-7) were blended at the ratios shown in Table 2 and melt-kneaded at 210 ° C. with an extruder to prepare pellets. The pellet was molded to prepare a test piece, and the tensile strength and elongation were measured. During the preparation of the pellets, 0.5% by weight of a lubricant (alkyl amide wax) was added to the composition ((A) + (B)) and melt-kneaded. Heat aging was performed at 140 ° C. for 100 hours, and the state of seepage of the lubricant on the surface was visually observed, and evaluated in the following five grades. Comparative Example 1 The modified polyacetal copolymer (B) of the present invention was not added.
The same evaluation as in the above example was performed for only a commercially available polyacetal resin.

Table 2 also shows the results.

[0027]

[Table 2]

Examples 8 to 14, Comparative Example 2 20 parts by weight of polyurethane (adipate) based on 100 parts by weight of the composition pellets of Examples 1 to 7 and Comparative Example 1.
Was added and melt-kneaded at 210 ° C. to prepare a test piece, and the tensile strength and elongation and Izod impact strength were measured. Further, the surface of the test piece was carefully observed to examine unevenness due to poor dispersion and surface peeling state. Table 3 shows the results.

[0029]

[Table 3]

Claims (1)

(57) [Claims] (1) 20-99% by weight of polyacetal resin (based on (A) + (B)) and (B) a unit represented by the following general formula (1) in the main chain:
80-1 modified polyacetal copolymer containing 0.1-50% by weight
A polyacetal resin composition comprising% by weight (based on (A) + (B)). Embedded image