JPH05155958A - Production of acetal polymer and copolymer - Google Patents

Abstract

PURPOSE:To produce an acetal (co)polymer at a high yield by (co)polymerizing trioxane in the presence of a cation-active catalyst contg. a specified amt. of a phenol compd. CONSTITUTION:Trioxane is polymerized or copolymerized with a copolymerizable monomer (e.g. epichlorohydrin or methyl glycidyl formal) in the presence of a cation-active catalyst (e.g. BF3) contg. at least one compd. selected from the group consisting of phenol, a phenol deriv. (e.g. trimethylphenol), and a sterically hindered phenol {e.g. tetrakis[methylene(3,5-di-t- butyl-4-hydroxyhydrocinnamate)]methane} in an amt. of 1-100ppm based on the total amt. of the monomer or monomers, enabling prolonged stable production of an acetal polymer or copolymer at a high yield heretofore unattainable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an acetal polymer or copolymer obtained by polymerizing trioxane or copolymerizing a comonomer copolymerizable with trioxane.

[0002]

Polymers with homo- and copolymers of formaldehyde or its cyclic oligomers, such as trioxane or tetraoxane, and with homo- and copolymers of cyclic acetals or ketals, such as 1,3-dioxolane, using cationically active catalysts. And a method for producing the copolymer are known and widely used industrially.

However, most of these cationically active catalysts are not sufficient in terms of polymerization activity, and a certain amount of catalyst is required to satisfy the polymerization yield. Therefore, not only the post-treatment such as deactivation and washing becomes complicated, but also the thermal stability of the product is affected. When an organic solvent solution of a Lewis acid catalyst, which is generally used as a cationically active polymerization catalyst, is continuously used for a long time, generation of tar-like precipitates is observed in a pipe to which the catalyst solution is added,
It becomes a problem in continuous operation. Japanese Examined Patent Publication (Kokoku) No. 3-63965 discloses that, prior to polymerization, sterically hindered phenols are added to the monomer in an amount of 0.001-2.
A polymerization method is described which comprises adding 0% by weight.
However, the improvement of the polymerization yield is not satisfactory, and there is no description regarding prevention of the formation of tar-like precipitates.
Japanese Examined Patent Publication No. 55-18443 discloses trioxane 1000 containing a phenol or a phenol-substituted compound as a chain transfer agent.
It describes a polymerization method comprising adding about 0.1 to 5.0 moles relative to the moles, but there is no description relating to improvement of polymerization yield and prevention of formation of tar-like precipitates.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides an acetal polymer or copolymer for obtaining a high polymerization yield and stable operation for a long time, which cannot be achieved by the conventional method for producing an acetal polymer or copolymer. The present invention relates to a method for manufacturing a united body.

[0005]

Means for Solving the Problems As a result of intensive studies to solve this problem, the present inventors have found that a high polymerization yield and stable operation for a long time can be obtained in the production method of the present invention. They have found the present invention. That is, the present invention, in the presence of a cationically active catalyst, when carrying out the polymerization of trioxane or copolymerization with a comonomer copolymerizable with trioxane, in advance the cationically active catalyst, phenol, phenol substitution product and sterically hindered phenols. A method for producing an acetal polymer and a copolymer, wherein at least one selected from the above is mixed in an amount of 1 to 100 PPM with respect to the total amount of monomers.

The present invention will be described in detail below. The phenol or phenol substitution product used in the present invention is represented by the following general formula (I).

[0007]

[Chemical 1]

(Wherein R ₁ and R ₅ are each a hydrogen atom, a halogen atom or an alkyl group, and R ₂ and
R ₃ and R ₄ are each a hydrogen atom, a halogen atom, an alkyl group, a nitro group, an alkoxy group or an aryl group. ) As a phenol or a phenol substitution product, for example,
Phenol, cresol, xylenol, trimethylphenol, tetramethylphenol, pentamethylphenol, ethylphenol, propylphenol, o-
Examples include chlorophenol, 3,5-dichlorophenol and the like.

Further, the sterically hindered phenols used in the present invention are antioxidants or free radical scavengers generally used in the plastics field. Specifically, 2-2'-methylenebis (4methyl-6-t-butylphenol), hexamethyleneglycol-bis (3,5-di-t-butyl-4hydroxyhydrocinnamate), tetrakis [methylene ( Three
5-di-t-butyl-4-hydroxyhydrocinnamate)] methane, triethylene glycol-bis-3-
(3-t-butyl-4-hydroxy-5-methylphenyl) propionate, 1,3,5-trimethyl-2,
4,6-Tris (3,5-di-t-butyl-4-hydroxy-benzyl) benzene, 4,4'methylenebis (2,6-di-t-butylphenol, octadecyl-
3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, distearyl-3.5-di-t
-Butyl-4-hydroxybenzylphosphonate, 2-
t-butyl-6- (3-t-butyl-5-methyl-2-
Examples thereof include hydroxybenzyl) -4-methylphenyl acrylate.

In the present invention, two or more kinds of phenols, phenol substitution products or sterically hindered phenols may be used. An important point in the present invention is to use these phenols, phenol-substituted compounds or sterically hindered phenols (hereinafter referred to as phenols) in advance with a cationically active catalyst. Examples of the cationically active catalyst include Lewis acid catalysts generally used for polymerization of trioxane and the like, protonic acids, and catalysts of their esters or anhydrides. Examples of Lewis acid catalysts include halides of boron, tin, titanium, phosphorus, arsenic and antimony, and specific examples include boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentafluoride, phosphorus pentachloride. , Arsenic pentafluoride, antimony pentafluoride and complex compounds or salts thereof. Further, specific examples of the protic acid, its ester or anhydride include:
Examples thereof include perchloric acid, trifluoromethanesulfonic acid, perchloric acid-t-butyl ester, acetyl perchlorate and trimethyloxonium hexafluorophosphate. The present invention is particularly effective for Lewis acid catalysts among these catalysts, and is particularly effective for boron trifluoride and its complex compounds or salts thereof. These catalysts are usually supplied to a polymerization apparatus as an organic solvent solution, and at least one of phenols is added and mixed in this solution. By using an organic solvent solution containing at least one of the above catalysts and phenols, it is possible to prevent the generation of tar-like precipitates and obtain a high polymerization yield.

The amount of the phenols added in the present invention is 1 to 100 PPM, preferably 1 to 10 PPM, based on the total amount of the monomers. If the addition amount is 1 PPM or less, a satisfactory polymerization yield cannot be obtained. Also, the addition amount is 100P
When it is more than PM, it is economically disadvantageous and is not preferable. The method of the present invention is effective in the polymerization of trioxane alone and the copolymerization of trioxane with at least one comonomer capable of being polymerized.

In the case of copolymerization, not only the copolymerization with at least one comonomer copolymerizable with the main monomer,
It is also effective in multi-component copolymerization of two or more kinds. This also includes comonomers that produce polymers with branched or pendant structures in the molecule. As the comonomer, a cyclic ether represented by the following general formula (II)

[0013]

[Chemical 2]

(Where R₁, R₂, R₃Or R_FourIs it
Each substituted by hydrogen atom, alkyl group or halogen
R means a methylene group or an oxymethylene group, and R_FiveIs
Methylene group or oxymethylene group or respectively alkyl group
Methyl group substituted with a vinyl group or a halogenated alkyl group
Group or oxymethylene group (wherein p is 0 to 3)
Represents an integer. ) Or formula- (CH₂)_q-OCH₂-
Or- (OCH₂CH ₂)_q-OCH₂2 indicated by-
Valent group (in this case, p represents 1 and q represents an integer of 1 to 4)
You ) Means. The alkyl group has a carbon number of 1 to 5
However, 1 to 3 hydrogens are replaced with halogen atoms, especially chlorine atoms.
May be done. ) For example epichlorohydrin, ethylene
Oxide, 1,3-dioxolane, diethylene glycol
Le formal, 1,4-butanediol formal,
1,3-dioxane, propylene oxide and the like can be mentioned.
It

Furthermore, cyclic esters such as β-propiolactone and vinyl compounds such as styrene or acrylonitrile are also used. Further, as a comonomer for forming a branched or linear molecular structure, alkyl-mono (or di) -glycidyl ether (or formal), for example, methyl glycidyl formal, ethyl glycidyl formal, propyl glycidyl formal, butyl glycidyl formal, ethylene glycol diglycidyl ether. , Triethylene glycol diglycidyl ether and bis (1,2,6-hexanetriol) triformal.

The polymerization or copolymerization of the present invention is carried out, for example, by bulk polymerization. The bulk polymerization can be carried out batchwise or continuously, and a method is generally used in which a monomer in a molten state is used to obtain a solid powdery polymer as the polymerization proceeds. As the polymerization apparatus used in the present invention, a reaction vessel with a stirrer which is generally used in a batch system can be used, and as a continuous system, a cokneader, a twin screw type continuous extrusion mixer, a twin screw paddle type continuous mixing machine is used. A continuous polymerization device such as a polymerization machine can be used, and two or more types of polymerization machines can be used in combination.

The polymerization temperature is preferably 60 to 200 ° C.,
More preferably, it is in the temperature range of 60 to 140 ° C. The polymerization time is related to the amount of the catalyst and is not particularly limited, but generally a polymerization time of 15 seconds or more and 20 minutes or less is selected. The polymer taken out from the outlet of the polymerization machine after a predetermined time has passed is usually a lump or powder, and a part or all of the unreacted monomer is separated and supplied to the next step. The reaction system after the polymerization is preferably mixed with ammonia, amines such as triethylamine and tri-n-butylamine, hydroxides of alkali metals and alkaline earth metals, and other known catalyst deactivators. Alternatively, it is preferable to neutralize and deactivate the polymerization catalyst by adding and treating a solution containing these deactivators. In this case, when the produced polymer is in the form of a large lump, it is, of course, preferable that the polymer is once pulverized and then treated.

The polymer thus obtained is further subjected to a stabilizing treatment. Stabilization treatment is oxymethylene homopolymer, the end is blocked by esterification or etherification, urethanization, etc. If it is a copolymer, it is heat-melted or heated in an insoluble or soluble liquid medium, This is achieved by selectively decomposing and removing unstable portions.

[0019]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto.

[0020]

Example 1 A 5 liter kneader having two stirring blades with a jacket capable of passing a heat medium was heated to 80 ° C.
2 kg of trioxane, 1.14 ml of methylal as a molecular weight regulator, and 45 gr of ethylene oxide as a comonomer were added. In addition to this, boron trifluoride diethyl ether and tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)]
Cyclohexane solution containing methane (Irganox 1010 manufactured by Ciba-Geigy) (boron trifluoride and tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane per weight of trioxane and ethylene oxide] methane Concentration of 30PPM and 5 respectively
PPM) was added to initiate the polymerization. Then, after 20 minutes, 2 liters of a 0.1% aqueous solution of tributylamine was added to the kneader to stop the reaction, and the contents were taken out. The contents were washed with acetone and dried, and the result of measuring the polymerization yield was
The polymerization yield was 91%. On the other hand, when the cyclohexane solution was allowed to stand for 1 week, no change was observed and no tar-like precipitate was observed.

[0021]

Example 2 The same operation as in Example 1 was carried out except that ethylene oxide was not added. The polymerization yield was 94%.

[0022]

Comparative Example 1 The same operation as in Example 1 was carried out except that a cyclohexane solution containing only boron trifluoride diethyl ether was added. Polymerization yield is 80
%, And the cyclohexane solution generated tar-like precipitates after 4 days.

[0023]

Comparative Example 2 The same operation as in Example 2 was carried out except that the cyclohexane solution containing only boron trifluoride diethyl ether was added. As a result, the polymerization yield was 81%, and in a cyclohexane solution containing boron trifluoride diethyl ether, tar-like precipitates were observed after 3 days.

[0024]

Example 3 The same operation as in Example 1 was performed except that tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane was replaced with phenol in Example 1. went. The polymerization yield was 93%. A cyclohexane solution containing boron trifluoride diethyl ether and phenol was allowed to stand for 1 week, but no change was observed and no tar-like precipitate was observed.

[0025]

Example 4 The same operation as in Example 1 except that tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane was changed to trimethylphenol. I went. The polymerization yield was 94%, and the cyclohexane solution containing boron trifluoride diethyl ether and trimethylphenol did not generate tar-like deposits even after standing for 10 days.

[0026]

According to the present invention, a high polymerization yield can be obtained,
Further, it is possible to prevent tar-like deposits from being generated in the catalyst solution.

Claims (1)

[Claims] 1. When conducting polymerization of trioxane or copolymerization with a comonomer copolymerizable with trioxane in the presence of a cationically active catalyst, the cationically active catalyst is previously mixed with a phenol, a phenol substitution product and a sterically hindering property. A method for producing an acetal polymer and a copolymer, wherein at least one selected from phenols is mixed in an amount of 1 to 100 PPM with respect to the total amount of monomers.