JPH02166120A - Production of polyacetal copolymer - Google Patents

Abstract

PURPOSE:To obtain the title copolymer useful as a nucleator used for molding a polyacetal resin by copolymerizing trioxan with a specified polyglycidyl ether in the absence of any cyclic ether. CONSTITUTION:Trioxan is copolymerized with at least one polyglycidyl ether reactive therewith having at least two epoxy rings in the molecule (e.g. 1,4- butanediol diglycidyl ether) in the absence of a cyclic ether, desirably in the presence of a polymerization catalyst (e.g. boron trifluoride/dibutyl etherate) and a chain transfer agent (e.g. methylal) and in the presence (absence) of an organic medium [an aliphatic or aromatic (halo)hydrocarbon].

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel method for producing a polyacecool copolymer and a structural nucleating agent for a polyacetal resin, mainly comprising the polyacetal copolymer.

More specifically, the present invention relates to the production of a polyacetal copolymer characterized by having a branched and/or crosslinked (reticulated) structure in the molecule, which is suitably used as a nucleating agent for polyacetal resin. The present invention mainly relates to a polyacetal resin structure nucleating agent including the method and the method.

(Prior Art) The polyacetal resin structure nucleating agent as used in the present invention refers to a polyacetal resin structure nucleating agent having a branched and ( or) refers to crosslinked (softened) polyoxymethylene, which has branches and is suitably used as a nucleating agent for polyacetal resin.
Or) As a method for producing crosslinked (m-shaped) polyoxymethylene, a ternary copolymerization technique using trioxane, at least one cyclic ether capable of reacting with trioxane, and at least one polyfunctional glycidyl ether capable of reacting with trioxane is used. Japanese Patent Publication No. 42-3955 discloses that it can be obtained by polymerization.

(Problem B to be solved by the invention) The branched and/or cross-linked (11-shaped) polyoxymethylene produced by the above-mentioned prior art is used as a nucleating agent during the molding process of polyacetal resin. However, its effect as a nucleating agent is not necessarily sufficient, and its improvement is desired.

For example, an example of the use of branched and/or crosslinked (reticulated) polyoxymethylene produced by the prior art is as a nucleating agent for polyoxymethylene films; Polyoxymethylene with branches and/or crosslinking (m-shaped) has insufficient surface roughness improvement based on the spherulite diameter. ) The development of crosslinked (Wii-shaped) polyoxymethylene is strongly desired.

An object of the present invention is to provide a method for producing a polyacetal copolymer which has a nucleating effect superior to that of conventional branched and/or crosslinked polyoxymethylene.

(Means for Solving the Problems) In order to further improve the nucleation effect of branched and/or crosslinked (reticulated) polyoxymethylene, the present inventors have proposed 4i! ! (
We focused on the need to increase the crystallinity of polyoxymethylene (reticulated) and conducted extensive studies.

In order to improve the crystallinity of branched and/or cross-linked (rope-shaped) polyoxymethylene, the present inventors have discovered that trioxane and at least one type of polyoxymethylene that reacts with trioxane contain at least two molecules per molecule. A branched and/or crosslinked (reticulated) polyacetal copolymer with a remarkable nucleating effect is obtained by copolymerizing a polyfunctional glycidyl ether having 1 or more epoxy rings in the absence of a cyclic ether. We have discovered a method for producing a copolymer and a structural nucleating agent mainly composed of a polyacetal resin, which is made of a polyacetal copolymer.

That is, the present invention provides a method of copolymerizing trioxane and at least one type of polyfunctional glycidyl ether having at least two or more epoxy rings in one molecule that can react with trioxane in the absence of a cyclic ether. The present invention relates to a method for producing a novel polyacetal copolymer with particularly excellent nucleation effect, and a nucleating agent for a polyacetal resin structure mainly made of the copolymer.

The copolymer of the present invention is produced by copolymerizing trioxane and a polyfunctional glycidyl ether in the presence of a cationic polymerization catalyst and in the absence of a cyclic ether.

There are the following three groups as polyfunctional glycidyl ether compounds used in the present invention.

First, the first group is - Formula; (In the formula, and R8 are each a hydrogen atom or a hydrocarbon group with or without a substituent, and R1 and R2 may be the same or different. Also, m is an integer of 2 to 10, and n is an integer of 2 to 200.

It is a polyfunctional glycidyl ether derived from a polyalkylene glycol represented by the formula, and examples of polyfunctional glycidyl ether that can be used include polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and polybutylene glycol diglycidyl ether. Of the first group, diglycidyl ethers having a molecular weight of 800 or less are particularly preferably used because of their ease of acquisition and purification.

The second group includes polyfunctional glycidyl ethers derived from polyhydric aliphatic alcohols; examples of such glycidyl ethers include ethylene glycol diglycidyl ether, bucobylene glycol diglycidyl ether, and 1,3-butane. Diol diglycidyl ether, 1,4-butanediol diglycidyl ether,
Trimethylolpropane triglycidyl ether, trimethylolpropane diglycidyl ether, 1゜6-hexanethiol diglycidyl ether, pentaerythritol tetraglycidyl ether, pentaerythritol triglycidyl ether, pentaerythritol diglycidyl ether, 1゜7-hebutanediol di Examples thereof include glycidyl ether, 1°8-octanediol diglycidyl ether, and the like. Among the second group, 1,4-butanediol diglycidyl ether is particularly preferred because of its ease of availability and purification, and the large nucleating effect of the resulting copolymer.

The third group includes polyfunctional glycidyl ethers derived from polyhydric aromatic alcohols; examples of such glycidyl ethers include hydroquinone diglycidyl ether, resorcinol diglycidyl ether,
Examples include catechol diglycidyl ether, pyrogallol triglycidyl ether, bisphenol A diglycidyl ether, epoxyphenol novolak resin, and epoxycresol novolak resin.

In producing the polyacetal copolymer of the present invention, it is preferable not to use a cyclic ether as a copolymerization component, that is, to carry out the process in the absence of a cyclic ether, in order to obtain a better nucleating effect by blending it with a polyacetal resin etc. It is necessary for

However, in addition to the above-mentioned copolymerization components, various commonly used known copolymerizable monomers may be used in combination in the production of the polyacecooled copolymer.

The weight ratio of trioxane and polyfunctional glycidyl ether to be copolymerized is 99°99 to 90% by weight of trioxane and 0.01 to 10% by weight of polyfunctional glycidyl ether.
When the amount of polyfunctional glycidyl ether is less than 0.01% by weight, the obtained copolymer has no nucleating effect and the amount of polyfunctional glycidyl ether is less than 10% by weight. When the range exceeds % by weight, the copolymer becomes excessively crosslinked and post-treatment becomes difficult.As the cationic polymerization catalyst used in the present invention, tin tetrachloride, tin tetrachloride,
Tin tetrabromide, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony trifluoride, boron trifluoride, boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, boron trifluoride So-called Friedel-Crafts type compounds such as acetic anhydrate, boron trifluoride coordination compounds such as boron trifluoride triethylamine complex; perchloric acid, acetyl perchlorate,
Inorganic and organic acids such as hydroxyacetic acid, trichloroacetic acid, and p-toluenesulfonic acid; complex salts such as triethyloxonium tetrachloroborate, triphenylmethylhexafluoroantimonate, allyldiazonium hexafluorophosphate, allyldiazonium tetrafluoroborate, etc. Compounds include alkyl metals such as diethylzinc, triethylaluminum, and diethylaluminum chloride.

These cationic polymerization catalysts are used in an amount of o,oos to 5 parts by weight based on 100 parts by weight of the starting material. Copolymerization is carried out without a solvent or in an organic medium.

Organic media that can be used in the present invention include:
Aliphatic hydrocarbons such as n-pentane, n-hexane, n-hebutane, n-octane, cyclohexane, cyclopentane; aromatic hydrocarbons such as benzene, toluene, xylene; methylene chloride, chloroform, carbon tetrachloride, chloride Examples include halogenated aliphatic hydrocarbons such as ethylene and trichloroethylene; and halogenated aromatic hydrocarbons such as chlorobenzene and 0-dichlorobenzene. These organic media may be used alone or in combination of two or more.

The concentration of the molecular weight regulator in the reaction system is as follows:
Molecular weight modifiers that can be used in the present invention include acetals, alcohols, carboxylic acids, carboxylic acid anhydrides, polyethers, etc. It is.

There is no particular restriction on the reaction time, but it can range from 1 second to 300
Set between minutes.

The reaction temperature is usually set between -20 and 230°C, more preferably between 20 and 210°C in the case of no solvent, and between -10 and 120°C in the case of using an organic medium. is more preferable.

After a predetermined period of time has elapsed, a polymerization terminator is added to the reaction system to complete the copolymerization. The obtained copolymer is stabilized by capping unstable terminal groups by a method such as esterification. Stabilizers and the like are added to the stabilized polyacecool copolymer before it is put into practical use.

The molecular weight of the copolymer obtained in the present invention can be determined by melt index measurement and liquid chromatography. Further, the number average molecular weight of only the oxymethylene polymer portion of the main chain can be determined by quantifying the terminal group using an optical analysis method using IR. Furthermore, the amount of polyfunctional glycidyl ether inserted into the molecule can be determined by hydrolyzing the obtained polymer in a dilute aqueous hydrochloric acid solution and quantifying the decomposed polyalcohol using gas chromatography and liquid chromatography. Can be done.

From these values, it is possible to calculate the number of crosslinks in one molecule and the crosslink density.

In general, a polyacecool copolymer with a high crosslink density can be expected to have a greater nucleation effect than a polyacetal copolymer with a low crosslink density.

The nucleating agent of the present invention uses the polyacetal copolymer obtained by the production method according to the present invention alone, or within the range that does not impede the nucleation effect of the polyacetal copolymer.
Small amounts of other known nucleating agents may also be included.

In addition, the nucleating agent of the present invention can be used not only for conventionally known l-shaped polyacetal resins, but also for any other materials that require improvement in physical properties such as transparency through (micro)crystallization, such as polyester, polyoxymethylene, and polypropylene. It is also applicable to thermoplastic resins.

The present invention will be specifically explained by the following examples, but these are not intended to limit the scope of the present invention (Examples) Examples of the present invention will be shown below.

Example 1 2000 g of purified trioxane and purified 1. 4.5 g of 4-butanediol diglycidyl ether was kept at 72°C and charged into a commercially available 31-volume batch-type Niguu that was purged with nitrogen gas, 0.84 g of methylal was added as a chain transfer agent, and fluoride was added as a polymerization catalyst. After adding 0.09 g of boron dibutyl etherate, polymerization was carried out by stirring for 20 minutes. The polymerization catalyst was deactivated by washing the obtained copolymer in an excess 1% triethylamine aqueous solution, the polymer was separated by filtration, and then thoroughly washed with acetone.
When dried at 0° C., 1450 g of a white polymer was obtained.

50g of the polyacecool copolymer thus obtained
was heated with 500 g of acetic anhydride and O1Ig of potassium acetate at 153° C. for 2 hours to obtain 49 g of a stable polyacetal copolymer.

This copolymer is made from a high viscosity polyacetal homopolymer (
1% by weight in Tenac@3010) manufactured by Asahi Kasei Corporation
and melt-kneaded using a 30 mm diameter extruder to prepare a polyacetal composition.

The spherulite diameter of this composition was measured using a light scattering method and was 1.5.
μm, and a significantly small spherulite diameter was obtained.

Examples 2 to 12 2000 g of purified trioxane was placed in the batch-type Nigu, which was kept at 72°C and replaced with nitrogen gas, as shown in Example 1.
The polyfunctional glycidyl ether shown in Table 1 was charged, and after adding 0.84 g of methylal and 0.09 g of boron fluoride dibutyl etherate, the mixture was stirred for 20 minutes to carry out polymerization. The obtained copolymer was subjected to deactivation of the polymerization catalyst, washing, drying, and terminal stabilization of the copolymer in the same manner as described in Example 1 to obtain a stable polyacetal copolymer.

1% by weight of the copolymer obtained in each example was added to the high viscosity polyacetal homopolymer used in Example 1,
Polyacecool compositions were prepared in the same manner as described in Example 1, and the spherulite diameters of each composition measured by light scattering method are shown in Table 1.

(Comparative Examples) Comparative Examples 1 to 6 2000 g of purified trioxane, 49 g of ethylene oxide, and polyfunctional glycidyl ether in the amounts shown in Table 2 were placed in a batch-type Ni-Goo that was kept at 72°C and replaced with nitrogen gas as shown in Example 1. , 0.84 g of Methicool, and 0.09 g of boron fluoride dibutyl etherate were charged, and the mixture was stirred for 20 minutes to carry out polymerization.

The obtained copolymer was subjected to deactivation of the polymerization catalyst, washing, drying, and terminal stabilization of the copolymer in the same manner as described in Example 1 to obtain a stable polyacetal copolymer.

A polyacetal composition was prepared in the same manner as described in Example 1 by adding 1% by weight of the copolymer obtained in each comparative example to the high viscosity polyacetal homopolymer used in Example 1.

Table 2 shows the spherulite diameters measured by light scattering for each composition. In these comparative examples, because ethylene oxide was copolymerized, sufficiently small spherulite diameters could not be obtained in any of them. .

Table 1 Table 2 (Effects of the Invention) As explained above, the polyacetal copolymer produced by the production method of the present invention has no amorphous portion based on the cyclic ether unit of the raw material comonomer in the molecule. Therefore, it is expected that the degree of crystallinity will be further improved, and when used as a structural nucleating agent for thermoplastic resins such as polyacetal resins, it will provide more excellent effects.

(1 other person)

Claims (2)

[Claims] (1) It is characterized by copolymerizing trioxane and at least one type of polyfunctional glycidyl ether having at least two or more epoxy rings in one molecule that can react with trioxane in the absence of a cyclic ether. Manufacturing method of polyacetal copolymer. (2) A structural nucleating agent consisting mainly of a polyacetal resin, comprising the polyacetal copolymer according to claim (1).