JPS62285909A - Production of oxymethylene copolymer - Google Patents

Abstract

PURPOSE:To obtain the title stable copolymer, by mixing trioxane with a cyclic ether and/or a cyclic acetal, bulk-polymerizing the mixture in the presence of a specified polymerization catalyst, adding a metal sulfite and a stabilizer to the reaction system and heating the mixture. CONSTITUTION:Trioxane is mixed with a cyclic ether and/or a cyclic acetal (e.g., 1,3-dioxolane). This mixture is bulk-polymerized in the presence of a polym erization catalyst selected from boron trifluoride (hydrate) and a coordination compound of boron trifluoride with an oxygen- or sulfur-containing organic compound (e.g. boron trifluoride diethyl etherate). A stable oxymethylene copoly mer containing oxymethylene units and oxyalkylene units is obtained by remov ing unstable end groups by decomposition by adding a metal sulfite and a stabi lizer (e.g., triphenylphosphine oxide) to the polymerization mixture after polymeri zation and heating the mixture to a temperature of 100-260 deg.C.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention involves copolymerizing trioxane and a cyclic ether and/or a cyclic acetal in bulk in the presence of a catalyst, and then copolymerizing sulfite. This invention relates to a method for obtaining a stable oxymethylene copolymer by removing unstable ends by adding a metal salt and a stabilizer and heating.

<Prior Art> Obtaining a polyoxymethylene homopolymer or copolymer by bulk polymerizing trioxane alone or trioxane and a cyclic ether and/or a cyclic acetal in the presence of a catalyst has been described, for example, in Japanese Patent Publication No. 5234/1983. It is publicly known. The obtained polymer is thermally unstable as it is, so in the case of a homopolymer (in the case of a homopolymer, it is terminal-blocked by esterification, etc.), and in the case of a copolymer, [
This is stabilized by decomposing and removing unstable terminals, but prior to this, it is necessary to stop the expansion by deactivating the catalyst. In other words, polyacetal homopolymers or copolymers obtained by cationic polymerization of trioxane, etc., will gradually depolymerize if the remaining catalyst is not deactivated, leading to a significant decrease in molecular weight and thermal damage. becomes extremely unstable.

Regarding the deactivation of boron trifluoride-based polymerization catalysts, US Pat. No. 2,989,509 proposes the use of aliphatic amines and heterocyclic amines. By removing these, the polymer is stabilized and no decrease in molecular weight is observed even if it is stored 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 melted or dissolved, resulting in a decrease in molecular weight. A decline is seen. Therefore, after deactivating the catalyst with amine t, it was essential to remove the catalyst from the polymer by thorough washing operations. For example, the special public
Methods for stabilizing the terminals of oxymethylene copolymers are described in Japanese Patent Publication No. 071 and Japanese Patent Publication No. 43-1875, but in these methods as well, the polymerization catalyst is quenched with an amine before stabilizing the terminals. It is removed by cleaning.

Means for Solving Problems〉 The present inventors overcame the shortcomings of conventional manufacturing methods and studied a method for manufacturing oxymethylene copolymers with excellent thermal stability based on iron content. If a metal sulfite or a metal sulfite and phosphine oxides are used instead of the amine in
It was found that this is stable. The present invention is based on these findings.

That is, the present invention provides a combination of a mixture of trioxane and a cyclic ether and/or a cyclic acetal with boron trifluoride, boron trifluoride hydrate, and a coordination compound of boron trifluoride and an organic compound containing an oxygen atom or a sulfur atom. Producing an oxymethylene copolymer containing oxymethylene units and oxyalkylene units by bulk polymerization in the presence of at least one polymerization catalyst selected from the group consisting of (
At this time, a method for producing an oxymethylene copolymer is characterized in that a metal sulfite and a stabilizer are added after polymerization, and then heated as is in a temperature range of 100 to 260 ° C. to obtain a stable oxymethylene copolymer. Preferably, a sulfite metal salt and a phosphine compound represented by the following formula (2)-
This is a method for producing the above-mentioned oxymethylene copolymer using Cytos in combination.

(However, R1, R2, R3 are each an alkyl group, a cycloalkyl group, an aryl group, a halogenated alkyl group,
(R-substituted aryl group, alkoxy group, aryloxy group, which may be the same or different) According to the present invention, when the degree of polymerization is completed, sulfite metal salt and stabilizer or sulfite metal salt, phosphine oxyto This is a very innovative production method because it can stabilize the terminals without going through a washing process by simply adding a stabilizer and a stabilizer.

The cyclic ether or cyclic acetal used in the present invention means a compound represented by the general formula IB+.

(However, in the formula, yl~Y4 is a hydrogen linkage, carbon number 1~6
represents an alkyl group or a halogenated alkyl group having 1 to 6 carbon atoms, and may be the same or A.

Moreover, X represents a methylene group or an oxymethylene group,
It may be substituted with an alkyl group or a halogenated alkyl group, and m represents an integer of O to 3. Or X is just CH
2bOCH2- or -OCH2beCH2-roCH, -0-, in which case m=l and p is an integer from 1 to 3).

Specific examples of cyclic ethers or cyclic acecules include ethylene oxide, propylene oxide, 1.
3-dioxolane, 1.3-dioxane, 1.3-dioxolane, 1,3.5-trioxepane, 1,3.5-
Trioxocane, 1.3.6-1-lioxocane and epichlorohydrin are preferred.

The polymerization catalyst is one or more selected from the group of boron trifluoride, boron trifluoride hydrate, and coordination compounds of boron trifluoride and organic compounds having oxygen or sulfur atoms in gaseous, liquid, or suitable form. It is used as a solution in an organic solvent. = Alcohol as a coordination compound with boron fluoride,
Examples include ether, phenol, sulfide, etc. As the catalyst, coordination compounds of boron trifluoride are particularly preferred, and boron trifluoride diethyl etherate and boron trifluoride dibutyl etherate are particularly preferred.

Examples of organic solvents include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as n-hexane, n-hebutane, and cyclohexane, and methanol.
・Alcohols such as alcohol, ethanol, chloroform,
Halogenated hydrocarbons such as dichloromethane and 1,2-dichloroethane! , acetone, and ketones such as methyl ethyl ketone.

The polymerization catalyst is 5 x 10-6 to 1 mole of trioxane.
It is sufficient to use I X I O-1 mol, preferably L<it
I X l O-' ~ l X 10-2 mo # [al.

The polymerization reaction apparatus used in the production method of the present invention includes:
A kneader equipped with a Σ-type stirring blade and a cylindrical barrel are used as the reaction zone, and the barrel is equipped with a screw that is coaxial with the barrel and has a large number of interrupted parts. A mixer that meshes with each other,
It has a case equipped with a pair of parallel stirring shafts equipped with numerous paddles and a jacket for heating and cooling the surrounding parts. A self-cleaning stirring device that rotates while maintaining a slight tolerance is used.

In the production method of the present invention, the reaction heat during the initial stage of polymerization, the frictional heat caused by solidification of the contents, etc. As a result, the temperature of the dielectric system tends to rise, so a device that can control the temperature is preferable.

In addition, since the contents tend to solidify and apply a large amount of torque in the early stages of polymerization, a strong stirring ability is required. It may be divided into stages.

The degree of polymerization is preferably carried out at a temperature ranging from near the melting point of trioxane to near the boiling point of trioxane, that is, about 0°C to about 115°C. Particularly preferred is a temperature range of .

Examples of the sulfite metal salt used in the present invention include sodium sulfite, potassium sulfite, calcium sulfite, barium sulfite, and the like.

Further, the phosphine oxides that can be used in the present invention are represented by the general formula (2), and (R', R2, R3
each represents an alkyl group, a cycloalkyl group, an aryl group, a halogenated alkyl group, a substituted aryl group, an alkoxy group, or an aryloxy group, and may be the same or different. dicyclohexylphenylphosphine oxyto, tri(n-
Examples thereof include (butyl)phosphine oxide, (n-butyl)phenylphosphine oxide, and triphenylphosphate, with triphenylphosphine oxide being particularly preferred.

The amount of metal sulfite added may be at least the equivalent molar amount of the catalyst used. Even if the amount added is smaller than that, the catalyst deactivation effect will appear, but the heat resistance stability of the final polymer will be slightly lowered.

Stabilizers used in the present invention include oxidative stabilizers and thermal stabilizers, but a combination of both is particularly preferred.

As the oxidation stabilizer, hindered phenol-based oxidation stabilizers are preferred, but phosphorus-based or sulfur-based oxidation stabilizers may also be used.

Specifically, Sumilizer MDP-S, Irganox 1010, Irganox 259, Irganox 24
5. Irganox 1098, Irganox 1035
．． Irganox 565, Irganox 1076, Irganox 108k, Irganox 1222. Irganox 1330, Irganox MD 1024,
Irgafuos P-EPQFF, Tinuvin 234, Tinuvin 320, Tinuvin 326, Tinuvin 327, Tinuvin 328, Sanol LS2626, Mark AO-20,
Mark AO-30, Mark AO-40, Marri AO-5
0,? -ri AO-60, Mark PEP-8, Mark PE
P-4, mark 2L12, mark 1500, mark 522A.

Mark 260, Mark AO-23, Mark AO-412
S, Mark AO-503A, Mark LA-36, (all product names), and the like.

As a heat stabilizer, carboxylic acid polyamide, polyurethane, polyurea, polyvinylpyrrolidone, urea derivative,
Hydrazine derivatives, hydrazone derivatives, amylin compounds, etc. can be used.

In the present invention, after polymerization, a metal sulfite salt and a stabilizer, or a metal sulfite salt, a phosphine oxytate, and a stabilizer are added, and unstable terminals are decomposed and removed by heating without removing the catalyst by washing or the like. . Heating temperature is 100-26
The temperature is 0°C, preferably higher than the melting point of Po117.

Example The present invention will be explained below with reference to Examples and Comparative Examples.

Note that the intrinsic viscosity [η) inh and thermal decomposition rate KX (thermal decomposition rate at X° C.) in the examples are defined as follows.

(77) inh p containing 2% a-pinene
- Solution viscosity measured by dissolving 0.5 g of polymer in 100 ml of chlorophenol and troweling at 60°C.

KX Thermal decomposition rate measured in air at X℃ and tomato temperature.

W.O. WO: initial sample weight W Sample weight after a certain period of time KX is DuPont's thermal analyzer using 1090/1091 It was measured.

Example 1 A 31 kneader with two Σ-type stirring blades was used. 3000 g of trioxane, 75 ml of 1,3-dioxolane, and 200 ppm of BFs relative to trioxane (12 X l O-' mol per 1 mol of trioxane)・Et2
0 was added as a benzene solution and stirred at 60 to 80°C for 60 minutes. A molar amount of sodium sulfite (particle size of 200 μm or less) was added to the produced polymer in an amount 5 times the molar amount of the catalyst.
0.5% by weight of iba-(YeigY) and 0.5% by weight of dicyandiamide were added, and the mixture was heated and kneaded at 210°C for 20 minutes.

Example 2.3 A polymer was produced in the same manner as in Example 1, except that 50 times the molar amount of sodium sulfite was used.

Example 4.5 A polymer was produced in the same manner as in Example 1, except that in addition to 5 times the molar amount of sodium sulfite, triphenylphosphine oxide was added in an amount of 0.1.5 times the molar amount of the catalyst.

Example 6 3000 g of trioxane, 02 ml of 1,3-dioxepane, and 200 ppm of BF3/Et20 (4 moles of L2XIO to 1 mole of trioxane) were added to benzene in a 31 Nigu having two Σ-type stirring blades. It was added as a solution and stirred at 60-80°C for 60 minutes. Polymer produced? In contrast, sodium sulfite (particle size of 200 μm or less) and 5 times the molar amount of the catalyst were added.
Add twice the molar amount of triphenylphosphine oxyto,
In addition, Irganox 245 (CibaGe i
g) 0.5% by weight (g), and 5% by weight were added, and the mixture was heated and kneaded at 210° C. for 20 minutes.

Comparative Example 1 A polymer was produced in the same manner as in Example 1 except that tri(n-butyl)amine was used in place of sodium sulfite in an amount five times the molar amount of the catalyst.

Comparative Example 2 After polymerization was carried out in the same manner as in Example 1, the polymer was poured into an aqueous triethylamine solution of 596, stirred for 30 minutes, and filtered to obtain ffff1 of the polymer. Wash this polymer with water,
After drying, 0.5% by weight of Irganox 1010.
Add 0.5% by weight of dicyandiamide and heat at 210°C for 2 hours.
The mixture was heated and kneaded for 0 minutes.

Comparative Example 3 A polymer was produced in the same manner as in Example 1 except that triphenylphosphine oxyto was used in an amount 5 times the molar amount of the catalyst in place of sodium sulfite.

Table 1 shows the physical properties of the polymers obtained in Examples 1 to 6 and Comparative Examples 1 to 3.

From Example I and Comparative Example 1, it can be seen that the catalyst deactivation effect of sodium sulfite is significantly higher than that of ordinary amines, and the heat resistance stability of the obtained polymer is significantly high.

Furthermore, from Example 1 and Comparative Example 2, kneading with the addition of sodium sulfite has a greater catalyst deactivation effect than washing with a normal amine aqueous solution, and the heat stability of the obtained polymer is significantly higher. I understand that.

Examples 1 to 3 show that when the number of moles of sodium sulfite is smaller than the number of moles of the catalyst used, the heat resistance stability of the obtained polymer decreases. Moreover, the heat resistance stability is not affected by the large amount added.

From Example 1.4.5 and Comparative Example 3, it is clear that when sodium sulfite and triphenylphosphine oxide are used in combination, the heat resistance stability of the obtained polymer is better than when sodium sulfite is used alone, but when triphenylphosphine oxyto It can be seen that there is no MK deactivation effect when used alone.

In Example 6, 1,3-dioxolane was used as a copolymerization component, but the heat resistance stability of the obtained polymer was 1.3.
- Equivalent to Example 5 using dioxolane.

Table 2 shows the physical properties of the molded product of Example 1.6.

Table 2 <Effects of the Invention> As shown in the examples, by using the production method according to the present invention, oxymethylene with excellent heat resistance stability can be produced in an extremely simple process without removing the catalyst by washing. 11 copolymers can be used.

Claims (1)

[Claims] (1) A mixture of trioxane and a cyclic ether and/or a cyclic acetal consisting of boron trifluoride, boron trifluoride hydrate, and a coordination compound of boron trifluoride and an organic compound containing an oxygen atom or a sulfur atom. When producing an oxymethylene copolymer containing oxymethylene units and oxyalkylene units by bulk polymerization in the presence of at least one polymerization catalyst selected from the group, metal sulfite and a stabilizer are added after polymerization, and as it is 100 to 26
A method for producing an oxymethylene copolymer, which comprises heating in a temperature range of 0°C to obtain a stable oxymethylene copolymer.