JPS62267311A - Termination of polymerization reaction - Google Patents

Abstract

PURPOSE:To obtain a polymer having good thermal stability without removing a catalyst, by polymerizing trioxane or a mixture thereof with a cyclic ether, etc., in the presence of a catalyst, e.g. boron trifluoride, etc., and adding a specific hindered amine compound to terminate the polymerization reaction. CONSTITUTION:Trioxane or a mixture thereof with a cyclic ether and/or cyclic acetal, e.g. 1,3-dioxolane, etc., is solution or suspension polymerized in the presence of a polymerization catalyst, e.g. boron trifluoride, hydrate thereof and a coordination compound of the boron trifluoride with an organic compound containing oxygen or sulfur atom, e.g. diethyl ether, etc. A hindered amine compound expressed by the formula (R<1> is H or 1-30C monofunctional organic residue; R<2>-R<5> are 1-5C alkyl; n is an integer of >=1: R<6> is n-functional organic residue) is added to the formed polymer solution or suspension to terminate the polymerization reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention provides a method for deactivating a polymerization reaction catalyst such as trioxane using a novel polymerization terminator to terminate the polymerization reaction.

More specifically, when producing oxymethylene homopolymer or yokopolymer by solution polymerization or suspension polymerization of trioxane etc. using boron trifluoride-based catalyst 5X, a hindered amine compound ￥M is added to stop the polymerization reaction. This is an intermediate method.

<Prior art> It is disclosed in, for example, Japanese Patent Publication No. 36-14640 that an oxymethylene homopolymer or copolymer can be obtained by solution polymerization or g3 polymerization of trioxane alone or yotrioxane and a cyclic ether and/or a cyclic acetal. It is publicly known. Polymers obtained by solution polymerization or suspension polymerization are thermally unstable as they are, so in the case of homopolymers, the terminal groups are blocked by esterification etc.
In the case of copolymers, they are stabilized by decomposing and removing unstable end groups, but it is necessary to deactivate the catalyst and stop the polymerization reaction prior to this.

In other words, oxymethylene homopolymers and copolymers obtained by cationic polymerization of trioxane, etc., will gradually depolymerize if the catalyst remaining therein is not deactivated, leading to a significant decrease in molecular weight and thermal damage. This results in an extremely unstable polymer.

To deactivate a boron trifluoride polymerization catalyst, US Pat. No. 2,989,509 proposes the use of an aliphatic amine or a heterocyclic amine. It is stated that if these are removed by washing after activation, the polymer will be stabilized, and no decrease in molecular weight will be observed even if it is stored as is for a long period of time.

<Problems to be solved by the invention> However, even if the catalyst is deactivated with a normal amine compound, if the catalyst is not removed from the polymer by washing, when the polymer is dissolved or melted, M Polymerization occurs and a decrease in molecular weight is observed.

Therefore, after deactivating the catalyst with an amine compound, it was essential to remove the catalyst from the polymer by a thorough washing operation.

Therefore, the present inventors solved the above-mentioned problem of the prior art by T.
In order to achieve this goal, the present invention was arrived at as a result of intensive studies on deactivation of the borax trifluoride catalyst and termination of the polymerization reaction.

Means for Solving the Problems> That is, the present invention uses trioxane or a mixture of trioxane and a cyclic ether and/or a cyclic acetal to combine boron trifluoride, boron trifluoride hydrate, and boron trifluoride with A polymer solution or a polymer suspension obtained by solution polymerization or suspension polymerization in the presence of at least one polymerization catalyst selected from group 'b) consisting of coordination compounds with atoms or bound compounds containing sulfur atoms. The present invention provides a method for terminating a polymerization reaction, which comprises adding a hindered amine compound represented by the following general formula (I) to a suspension.

(However, in the formula, R1 represents a hydrogen atom or a monovalent organic residue with 1 to 30 carbon atoms, and R2 to R5 represent an alkyl group with 1 to 5 carbon atoms, and even if they are the same, they may be different from each other.) n represents an integer of 1 or more, and R6 represents an n-valent organic residue) The method for terminating the polymerization reaction of the present invention can be performed using trioxane alone or trioxane and a cyclic ether and/or (
The cyclic ether or cyclic acetal used in the present invention, which is carried out during solution polymerization or suspension polymerization of a mixture of cyclic acetals, means a compound represented by the following general formula (I1).

I Y 3-C-(X ) m (However, in the formula, Y1 to Y4: y, hydrogen atom, carbon number 1 to
6 alkyl group, carbon number] to 6 halogen-substituted alkyl group, which may be the same or different. Further, X represents a methylene or oxymethylene group, which may be substituted with an alkyl group or a halogen-substituted alkyl group, and m represents an integer of O to 3; i
(CH+)p-0-CH2- or -○-CH)
(CH2) may be -OC''H2-, in which case m = 1, and p is an integer of 1 to 3) Cyclic ether or cyclic ether represented by the above general formula (I1) Among acecool, particularly preferred compounds include niterene oxide, propylene oxide, 1,3-dioxolane, 1-53-dioxane, 1°3-dioxolane, 1,
3.5-) Lioxeban, 1,3,6-triochumcane, epichlorohydrin, etc. may be mentioned.

In the polymerization catalyst of the present invention, one or more compounds selected from the group of boron trifluoride, boron trifluoride hydrate, and coordination compounds of an organic compound having an oxygen or sulfur atom and borax trifluoride, It may be used in gaseous, liquid form or as a solution in a suitable organic solvent.

Examples of organic compounds having an M element or a sulfur atom that form a coordination compound \pJ with trifluoroboron include alcohols, ethers, phenols, sulfides, and the like.

Among these catalysts, coordination compounds of boron trifluoride are particularly preferred, and boron trifluoride/dinite etherate and boron trifluoride/dibutyl nitrate are particularly preferably used.

Examples of the solvent for the polymerization catalyst of the present invention include aromatic hydrocarbons such as benzene, toluene, and xylene, n-hexane,
Aliphatic hydrocarbons such as n-hebutane and cyclohexane, alcohols such as methanol and ethanol, halogenated hydrocarbons such as chloroform, dichloromethane and 1,2-dichloroethane, and ketones such as acetone and methyl ethyl ketone are used. Ru.

The amount of polymerization catalyst added is 5 to 1 mole of triokyfune.
It is in the range of ×10 to 1 × 10 mol, particularly preferably in the range of 1 × 10 to 1 × 10 mol.

The solvent used in the solution polymerization or suspension polymerization of the present invention may be inert to trioxane, cyclic ether or cyclic acetal, and the catalyst, such as n-hexane,
n-hebutane, aliphatic hydrocarbons such as cyclohexane, chloroform, halogenated hydrocarbons such as 1,2-dichloroethane, benzene1. Aromatic hydrocarbons such as toluene and xylene, and esters such as dimethyl adipate and dimethyl glutarate can be used, but n-hexane and cyclohexane are preferably used because they are particularly easy to produce polymers.

The polymerization reaction temperature for solution polymerization or bulk polymerization of the present invention is in the range of 0 to 100°C, preferably 20 to 80°C.
It is carried out over a temperature range of

Further, the polymerization reaction is preferably carried out under a dry inert atmosphere, for example under a nitrous gas or carbon dioxide gas atmosphere, and is usually carried out under normal pressure, but it can also be carried out under high pressure.

Examples of the hindered amine compound used in the invention include compounds having the following structural formula, but a tertiary amine type hindered amine compound is preferably used in view of the color tone of the obtained polymer.

The following margin is BTC: Yes 8!! Solvents include aromatic hydrocarbons such as benzene, toluene, and xylene, n-hexane, and n-hexane.
- Aliphatic hydrocarbons such as hebutane and cyclohexane, alcohols such as methanol and ethanol, halogenated hydrocarbons such as chloroform, dichloromethane and 1,2-dichloroethane, and ketones such as acetone and methyl ethyl ketone. .

The amount of the terminator of the present invention to be added is such that the number of nitrogen atoms having a hindered amine structure is preferably equal to or greater than the number of boron atoms in the boron trifluoride catalyst of the polymerization catalyst used. Even if the number of nitrogen atoms is less than the number of boron atoms, the catalyst deactivation effect can be seen, but the heat resistance stability of the obtained polymer will decrease slightly, so adjust the amount of addition m according to the desired degree of heat resistance stability. There is a need.

<Examples> Next, the present invention will be described with reference to Examples and Comparative Examples. Note that the intrinsic viscosity [η:l] shown in Examples and Comparative Examples
mi and thermal decomposition rate are measured as follows.

[η] l Tl In 100 ml of p-chlorophenol containing 112% α-pinene, 0.5 g of the polymer was dissolved and measured at 60°C.

Thermal decomposition rate at Kx X’C Using a sample of 10 mg of target, Under an air atmosphere using a thermobalance, The decomposition rate after a certain period of time was determined.

o-wt Kx=　　　　　　X100　　(%)WO WO: Sample weight before heating Wl: Sample weight after heating The thermobalance is a DuPont thermal analyzer. Measured using 1090/1091.

Example 1 2 equipped with a thermometer, stirrer, condenser and nitrogen inlet tube
The little round bottom flask was heated under reduced pressure and then cooled with a stream of dry nitrogen. In this flask, add 800 g of trioxane, 540 g of cycloxane, 20 g of 1,
3-dioxolane was charged. At this time, the water content of this reaction mixture was measured using a Karl-Fischer oven and was found to be 90 ppm.

The reaction mixture was then gradually heated in an oil bath while stirring. When the temperature of the contents reaches 60℃,
0.16 g (200 ppm relative to I"lioxane) of boron trifluoride diethyl etherate was added. After addition, exotherm started about 1 minute later, and the internal temperature rose to about 70°C. The material became cloudy and became a slurry. 15 minutes after adding boron trifluoride diethyl etherate as a catalyst, 5ano 1Ls765 (Ci ba
- 2.9 g (5 moles relative to the catalyst) of the hindered amine compound manufactured by Geigy, the above-mentioned compound of structural formula 0-2, was dissolved in 100 ml of benzene, and the mixture was stirred for 5 minutes. The contents were passed through a suction port, and the produced polymer was taken out and dried under reduced pressure.

[η]]Tlh of the obtained polymer, 222 and a
was measured, and the results are shown in Table 1 below.

Examples 2-4 Sano ILS765 0.14g, 0.57g, 2
A polymer was produced in the same manner as in Example 1, except that 9.0 g was used, and [η)nnh, Kw, and %Q were measured.

The results are shown in Table 1 below.

Example 5 A polymer was produced in the same manner as in Example 1 except that 27 g of 1,3-dioxolane was used instead of 1,3-dioxolane.

[η]ITlh, 222 and Q of the obtained polymer
was measured, and the results are shown in Table 1 below.

Comparative Example 11 A polymer was produced in the same manner as in Example 1, except that 0.57 g (5 times the mole relative to the catalyst) of triethylamine was used instead of Sano 1Ls765.

[η] 1nh, 222 and 222 of the obtained polymer were measured, and the results are shown in Table 1 below.

Comparative Example 2 A polymer was produced in the same manner as in Example 1, except that 1.05 g (5 times the mole relative to the catalyst) of tri(n-butyl)amine was used instead of Sanol LS765.

[η]+r+'n-, of the obtained polymer, 7z2 and K
m was measured and the results are shown in Table 1 below.

Comparative Example 3 The polymer of Comparative Example 1 was added to 2 liters of a 2% aqueous ammonia solution and stirred for 30 minutes. The polymer was removed from the suction port, washed twice with 1 liter of water, and then dried under reduced pressure.

[η) Inn' K722 and A of the obtained polymer were measured, and the results are shown in Table 1 below.

From Table 1 below, it can be seen that the hindered amine compound of the present invention has a greater catalyst deactivation effect than ordinary amine compounds, and that this effect is not affected by the copolymer components, and that it does not require removing the catalyst by washing etc. It is clear that it has excellent heat resistance stability.

<Effects of the Invention> The method for terminating a polymerization reaction according to the present invention does not require removal of the catalyst by washing, and by using the method for terminating a polymerization reaction, the production process of an oxymethylene polymer can be simplified.

Claims (1)

[Claims] Trioxane or a mixture of trioxane and a cyclic ether and/or cyclic acetal is combined with boron trifluoride, boron trifluoride hydrate, and boron trifluoride with an organic compound containing an oxygen atom or a sulfur atom. A polymer solution or suspension obtained by solution polymerization or suspension polymerization in the presence of at least one polymerization catalyst selected from the group consisting of coordination compounds is expressed by the following general formula (I). A method for stopping a polymerization reaction, which comprises adding a hindered amine compound. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (However, in the formula, R1 represents a hydrogen atom or a monovalent organic residue with 1 to 30 carbon atoms, and R2 to R5 are alkyl with 1 to 5 carbon atoms. (n represents an integer of 1 or more, and R6 represents an n-valent organic residue).