JPS62257922A - Termination of polymerization reaction - Google Patents

Abstract

PURPOSE:To obtain a polymer having remarkably high thermal stability without necessitating the removal of catalyst after polymerization, by adding a specific hindered amine compound as a polymerization terminator in the polymerization of trioxane, etc., using a boron trifluoride catalyst. CONSTITUTION:Trioxane or a mixture of trioxane and a cyclic ether and/or cyclic acetal is subjected to bulk polymerization in the presence of a catalyst selected from boron trifluoride, hydrated boron trifluoride and a coordination compound of boron trifluoride and an organic compound containing oxygen atom and sulfur atom, preferably at 60-95 deg.C under vigorous agitation. The obtained polymer is preferably pulverized to fine powder as far as possible and made to react with a polymerization terminator consisting of a hindered amine compound of formula I (R<1> is H or 1-30C univalent organic residue; R<2>-R<5> are 1-5C alkyl; R<6> is n-valent organic residue; n>=1) (e.g. the compound of formula II) preferably at 0-100 deg.C to obtain the objective polymer.

Description

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

More specifically, the present invention relates to a method of bulk polymerizing trioxane or the like using a boron trifluoride catalyst to produce an oxymethylene homopolymer or copolymer, and adding a hindered amine compound to stop the polymerization reaction.

<Prior art> To obtain a polyacetal homopolymer or copolymer by combining trioxane alone or trioxane with a cyclic ether and/or a cyclic acetal in bulk, it is known from the Japanese Patent Publication No. 1973-1999! This method is known from Japanese Patent No. 5234 and the like.

Polymers obtained by bulk polymerization are thermally unstable as they are, so in the case of homopolymers, the terminal groups are blocked with esters, etc., and in the case of copolymers, unstable terminal groups are blocked. Although it is stabilized by decomposition and removal, it is necessary to deactivate the catalyst and stop the polymerization reaction prior to this.

That is, the acetal homobolymer or copolymer obtained by cationic polymerization of trioxane etc. will gradually depolymerize unless the catalyst remaining therein is deactivated.
This may cause a significant decrease in molecular weight or result in a polymer that is extremely thermally unstable.

Regarding the deactivation of boron trifluoride polymerization catalysts, US Pat. No. 2,989,509 proposes the use of aliphatic amines or petrocyclic amines. It is stated that if these are removed by doing so, the polymer becomes stable and no decrease in molecular weight is observed even if it remains as it 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, depolymerization will still occur when the polymer is dissolved or melted. 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, in order to solve the problems of the above-mentioned conventional techniques, the present inventors conducted intensive studies on deactivation of the boron trifluoride catalyst and termination of the polymerization reaction, and as a result, they arrived at the present invention.

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 trioxane or a mixture of trioxane with a cyclic ether and/or a cyclic acetal. For a polymer obtained by bulk polymerization in the presence of at least one polymerization catalyst selected from the group consisting of coordination compounds with organic compounds containing oxygen atoms or sulfur atoms,
The present invention provides a method for terminating a polymerization reaction, which is characterized by adding a hindered amine compound represented by the following general formula (I).

(However, in the formula, R1 represents a hydrogen atom or a monovalent organic residue having 1 to 30 carbon atoms, and R2 to R5 represent 1J11 to 5 carbon atoms.
represents an alkyl group, which may be the same or different from each other. n represents an integer of 1 or more, and R6 is n
The polymerization reaction termination method of the present invention (representing a valent organic residue) uses trioxane alone or trioxane and a cyclic ether and/or
Alternatively, the term cyclic acetal used in the present invention refers to a compound represented by the following general formula (1), which is carried out when bulk polymerizing a mixture of cyclic acetals.

l (However, in the formula, Yl-Y4 is a hydrogen atom, carbon number 1-6
represents an alkyl group and a halogen-substituted alkyl group having 1 to 6 carbon atoms, 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 0 to 3. Alternatively, X is -(CH
2) p-〇-CH, - or -〇-CH2-(CH2)p
-〇-CH,-, in which case m = 1 and p is an integer of 1 to 3) In the cyclic ether or cyclic acetal represented by the above general formula (2) , particularly preferred compounds include ethylene oxide, propylene oxide, 1,3-dioxolane,
1.3-dioxane, 1°3-dioxolane, 1.3.
Examples include 5-) oxepane, 1.3.6-trioquinquan, and epichlorohydrin.

The polymerization catalyst of the present invention is characterized in that one or more compounds selected from the group of boron trifluoride, boron trifluoride hydrate, and coordination compounds of boron trifluoride and organic compounds having oxygen or sulfur atoms are It can be used in solid, liquid or solution form in a suitable solvent.

Examples of the organic compound having an oxygen or sulfur atom that forms a coordination compound with boron trifluoride include alcohol, ether, phenol, sulfite, and the like.

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

As the solvent for the polymerization catalyst of the present invention, aromatic carbons such as Hensen, toluene, and xylene (hydrogen, n-hexane,
Aliphatic hydrocarbons such as n-hebutane and cyclohexane, alcohols such as methanol and ethanol, halogenated carbide ice packs such as chloroform, dichloromethane and 1,2-dichloroethane, and ketones such as acetone and methyl ethyl ketone are used. Ru.

The amount of catalyst added is 5% per mole of trioxane.
The range is from ×10 to 1×10 mol, particularly preferably from 1X10 to 1×10 mol.

Various apparatuses are known for polymerizing trioxane alone or trioxane and cyclic ether and/or cyclic acetal in bulk, but the method for stopping the polymerization reaction of the present invention is not particularly limited by the apparatus, and On the other hand, if it is less than 10% by weight, it can be applied to polymerization reactions carried out in the presence of an organic solvent such as cyclohexane.

In bulk polymerization, since rapid solidification and heat generation occur during polymerization, an apparatus having strong stirring ability and capable of controlling the reaction temperature is particularly preferably used.

The bulk polymerization apparatus of the present invention having such performance uses a Nissin barrel as the kneader 1 reaction zone having a sigma-type stirring blade, and is equipped with a coaxial screw having a large number of interrupted threads in the barrel. , a mixer that operates so that this interruption meshes with teeth protruding from the inner surface of the barrel, and two conventional screw extruders that have a pair of mutually meshing parallel screws in a long case with a jacket for heating or cooling. A self-cleaning mixer, etc. that has a large number of paddles on a horizontal stirring shaft, and when the shafts are rotated simultaneously in the same direction, a slight clearance is maintained between each paddle surface and the inner surface of the case. Can you name it?

In addition, in bulk polymerization, strong stirring capacity is required because the polymerization solidifies rapidly in the initial stage of the polymerization reaction, but once the polymerization is pulverized, large stirring capacity is not required, so the bulk polymerization process can be repeated. It may be divided into stages.

The bulk polymerization reaction temperature is preferably in the temperature range from near the melting point to near the boiling point of trioxane, that is, in the range of 60 to 110°C, particularly preferably in the range of 60 to 95°C.

In the early stages of polymerization, the temperature inside the polymerization reactor tends to rise due to reaction heat and frictional heat from solidification, so it is desirable to control the reaction temperature by passing cooling water through the jacket, etc. .

The terminator used in the present invention, which deactivates the boron trifluoride catalyst and stops the polymerization reaction, may be added as it is or as a solution in an organic solvent and mixed.

When adding a terminator, the temperature is preferably controlled within the range of 0 to 100°C so that depolymerization does not proceed.

In addition, in order to cause the reaction between the terminator and the polymerization catalyst to occur sufficiently, it is preferable that the polymer be as thin as possible71), so before adding the terminator, the polymer should be pulverized using a pulverizer. Among these hindered amine compounds, tertiary amine type hindered amine compounds are particularly preferably used because the resulting polymer has an excellent color tone.

The terminator of the present invention may be added as is, but
In order to promote contact with the polymerization catalyst, it may be added as a solution overnight in an organic solvent. The organic solvent used in this case is aromatic hydrocarbons such as benzene, toluene, xylene, etc.
Aliphatic hydrocarbons such as n-'\xane, n-hebutane, and cyclohexane, alcohols such as methanol and ethanol, halogenated hydrocarbons such as chloroform, dichloromethane, and 1,2-dichloroethane, acetone,
Examples include ketones such as 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. Although the catalyst deactivation effect can be seen even if the number of nitrogen atoms is less than the number of boron atoms, the heat resistance stability of the obtained polymer will decrease slightly, so the amount added should be adjusted 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. In addition, the intrinsic viscosity [η)' shown in Examples and Comparative Examples
The inn and thermal decomposition rate are determined as follows.

(η) +nh p- containing 2% α-pinene
0.5 g of polymer was dissolved in 100 ml of chlorophenol and measured at 60°C.

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

~VO-WI Kx=
Measured using 91.

1 juice - 3000cc kneader with 2 Σ type stirring blades at 60℃
3000 g of trioxane, 75 g of 1,3-dioxolane, and 200 pp of boron trifluoride/diethyl etherate as a catalyst based on the weight of trioxane.
m was added as a 10% Hensen's solution and stirred at about 30 rpm.

The contents solidified within a few minutes and the temperature inside the system rose due to reaction heat and frictional heat, so we cooled it by passing compressed air inside the Σ-type stirrer, further lowered the rotation speed, and brought the maximum temperature to 80°C.
controlled until now.

60 minutes after the addition of the catalyst, the temperature was lowered to 40°C and a hindered amine compound (Ci
5anol Ls-765) 1 manufactured by ba-Gaigy
After adding 1.4 g as a 20% solution and stirring for an additional 12 minutes, the polymer was taken out. The obtained polymer was a white powder with an intrinsic viscosity [η) and nh=1.
It was 44.

Example 11 The same procedure as in Example 1 was carried out except that 2.14 g of triethylamine was used instead of the compound (G-2) as the soil catalyst deactivator. The obtained polymer was a white powder.

Moreover, the intrinsic viscosity [η) and pi+ were 1.21.

The thermal decomposition rates of the samples of Example 1 and Comparative Example were measured for changes over time, and the results are shown in Table 1.

Table 1. Polymer decomposition rate at 222° C. From Table 1, it is clear that the use of the hindered amine compound of the present invention provides superior thermal stability of the polymer.

Instead of the hindered amine compound (G-2), (K-2), (K-1) is used as a catalyst deactivator.
, (T-2), (T-1) and (U-]n each
The same procedure as in Example 1 was carried out except that 0.0 g was added. The resulting polymer was measured for its visual color, [η]ITlh, and decomposition rate when kept at 222°C for 30 minutes.

The results are shown in Table 2.

Table 2 From Table 2, it is clear that the thermal stability of polymers using hindered amine compounds is excellent. 0.57g, 1.14g for catalyst
, 11.4 g, and 114 g were polymerized in the same manner as in Example 1, except that 0.5% by weight of Irganox 1010 (hindered phenol heat resistant agent Ci ba-Ge i) was added to these polymers as a benzene solution. gy), added 0.1% by weight of hydrated calcium and heated at 210°C.
The mixture was melted and mixed for 20 minutes at /30 rpm.

2. Add triethylamine to the catalyst as a catalyst deactivator.
Polymers were produced in the same manner as in Examples 3 to 6, except that 14 g was used.

Table 3 shows the thermal decomposition rates and Km of [η] Yuzu in Examples 3 to 6 and Comparative Example 2.

Table 3 As is clear from Table 3, when the catalyst is deactivated by the hindered amine compound, it has very high thermal stability even without removing the catalyst by washing or the like. On the other hand, when the catalyst is deactivated with triethylamine,
The produced polymer also has low [η] and extremely poor heat stability.

A polymer was produced in the same manner as in Example 1, except that 42 g of ethylene oxide was used in place of 1,3-dioxolane. [η]1ph of this polymer is 1.3
6, Kz (30 minutes) was 10%, showing good heat resistance.

<Effects of the Invention> Since the polymer exuded from the polymerization reaction according to the present invention does not require removal of the catalyst, it is not only possible to significantly shorten the production process, but also to obtain a polymer with significantly improved heat resistance stability. You can do it.

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. The following general formula ( I
) A method for terminating a polymerization reaction, which comprises adding a hindered amine compound represented by: ▲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).