JPH051125A - Method for producing oxymethylene copolymer - Google Patents

Abstract

(57) [Summary] [Structure] When a trioxane and a cyclic ether are polymerized in the presence of a catalyst to produce an oxymethylene copolymer, a hindered amine compound is added after the polymerization is completed to deactivate the catalyst, and then a stabilizer is added. Add water to 100-2
A method for producing an oxymethylene copolymer, which comprises heating at 60 ° C. [Effect] The oxymethylene copolymer obtained by the present invention is excellent in thermal stability and mechanical properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the production of an oxymethylene copolymer by polymerizing trioxane and a cyclic ether in the presence of a catalyst. After the polymerization is completed, a hindered amine compound is added to deactivate the catalyst, and then a stabilizer is added. And a method for producing an oxymethylene copolymer having excellent thermal stability and mechanical properties by adding water and heating.

[0002]

2. Description of the Prior Art To obtain an oxymethylene homopolymer or copolymer by bulk polymerization of trioxane alone or trioxane and a cyclic ether is described, for example, in JP-B-44-
It is described in Japanese Patent No. 5234.

Since the obtained polymer is thermally unstable as it is, in the case of a homopolymer, the terminal group is blocked by esterification or the like, and in the case of a copolymer, the unstable terminal portion is decomposed. Although it has been removed and stabilized, it is necessary to deactivate the catalyst and terminate the polymerization reaction before that.

That is, an oxymethylene homopolymer or copolymer obtained by cationically polymerizing trioxane or the like gradually undergoes depolymerization unless the catalyst remaining therein is deactivated, resulting in a remarkable decrease in molecular weight. , Becomes a polymer that is extremely thermally unstable.

Regarding the deactivation of the boron trifluoride catalyst, Japanese Patent Publication No. 48-8342 discloses that a compound that forms a complex compound with a catalyst such as an alkali metal fluoride or a basic substance such as alkali carbonate is added. Later 0.01-10
A method of moistening with% water is described. Also,
A method is also known in which, after bulk polymerization of trioxane or the like with a boron trifluoride catalyst, a hindered amine compound or a metal sulfite is added to deactivate the catalyst (Japanese Patent Laid-Open No. Sho 63-63).
-12617, JP-A-63-12631).

[0006]

[Problems to be Solved by the Invention] However, Japanese Patent Publication No. 4
In the basic substance disclosed in JP-A-8-8342, the deactivation effect of the catalyst is insufficient, so that the thermal stability of the polymer is poor.
Further, the polymer in which the catalyst is deactivated by the hindered amine compound disclosed in JP-A-63-12617 and the metal sulfite disclosed in JP-A-63-12631 is
It has high thermal stability, but in recent years, good flowability has been required as the thickness of molded products has become thinner, and as a result, thermal stability to withstand even higher molding temperatures has become necessary. It is becoming less than satisfactory.

An object of the present invention is to solve the above problems and to produce an oxymethylene copolymer having excellent thermal stability.

[0008]

That is, the present invention provides a mixture of trioxane and a cyclic ether with boron trifluoride, boron trifluoride hydrate and an organic compound containing boron trifluoride and an oxygen atom or a sulfur atom. In producing an oxymethylene copolymer containing an oxymethylene unit and another oxyalkylene unit by polymerizing in the presence of at least one polymerization catalyst selected from the group consisting of coordination compounds,
After completion of polymerization, the following general formula

[0009]

[Chemical 2]

(Wherein R ¹ represents a hydrogen atom or a monovalent organic residue having 1 to 30 carbon atoms, and R ^{2 to} R ⁵ represent an alkyl group having 1 to ⁵ carbon atoms, which are the same as each other. May be present or different from each other, n represents an integer of 1 or more, and R ⁶ represents an n-valent organic residue) to deactivate the boron trifluoride catalyst by adding a hindered amine compound. After that, water is added together with a stabilizer, and the temperature is 100 ° C to 260 ° C.
A method for producing an oxymethylene copolymer is characterized by heating in a temperature range of ° C.

In the present invention, it is important to deactivate the catalyst with a hindered amine compound after the polymerization of the oxymethylene copolymer, add a stabilizer and water, and heat at a specific temperature range. It is possible to produce an oxymethylene copolymer having excellent stability and mechanical properties.

Among the cyclic ethers used in the present invention, preferred compounds include ethylene oxide, propylene oxide, 1,3-dioxolane, 1,3-dioxane,
1,3-dioxepane, 1,3,6-trioxocane,
Examples thereof include epichlorohydrin and phenylglycidyl ether, with ethylene oxide, 1,3-dioxolane and 1,3-dioxepane being particularly preferred. The copolymerization amount is usually 0.1 to 10 with respect to the oxymethylene unit.
It is in the range of mol%, preferably in the range of 0.2 to 6 mol%. If it is too small, the thermal stability of the obtained polymer will be low, and if it is too large, the mechanical strength and moldability will be poor, such being undesirable.

The polymerization catalyst of the present invention is one or more selected from the group consisting of boron trifluoride, boron trifluoride hydrate and a coordination compound of boron trifluoride with an organic compound containing an oxygen atom or a sulfur atom. The compounds are used in the form of a gas, liquid or a suitable organic solvent.

Among these catalysts, a coordination compound of boron trifluoride is particularly preferable, and boron trifluoride.
Diethyl etherate and boron trifluoride / dibutyl etherate are preferably used.

The addition amount of the polymerization catalyst is preferably in the range of 0.001 to 0.1 part by weight, and particularly preferably in the range of 0.005 to 0.05 part by weight, relative to 100 parts by weight of trioxane.

Various devices for polymerizing trioxane alone or trioxane and a cyclic ether in bulk are known, but the polymerization of the present invention is not particularly limited by the device, and bulk polymerization or an organic solvent such as cyclohexane is known. It can also be applied to a polymerization reaction carried out in the presence of

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

As the bulk polymerization apparatus of the present invention having such performances, a kneader having a sigma type stirring blade, a cylindrical parel as a reaction zone, and a screw having a large number of suspended peaks coaxially are used in the parel. A mixer that operates so that the interrupted portion and teeth protruding from the inner surface of the parell mesh with each other; a normal screw extruder having a pair of mutually parallel parallel screws in a long case having a jacket for heating or cooling; Self-cleaning mixer with multiple paddles on a horizontal stirring shaft of a book, and when the shafts are simultaneously rotated in the same direction, they rotate with a slight clearance between the paddle surface and the inner surface of the case. And so on.

Further, in the bulk polymerization, a strong stirring ability is required because it solidifies rapidly in the initial stage of the polymerization reaction, but once it is pulverized, a large stirring ability is not required thereafter, so the bulk polymerization is not required. The process may be divided into two steps.

The bulk polymerization reaction temperature is preferably in the range of 30 to 120 ° C, particularly preferably in the range of 60 to 90 ° C.

At the initial stage of polymerization, the temperature in the polymerization reactor tends to rise due to reaction heat and frictional heat caused by solidification. Therefore, control the reaction temperature by passing cooling water through the jacket. Is desirable.

The hindered amine compound which deactivates the boron trifluoride-based catalyst used in the present invention and terminates the polymerization reaction is represented by the above-mentioned general formula, and bis (2, 2, 6, 6) is typical. 6-tetramethyl-4-piperidinyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 1,2,3
4-Butanetetracarboxylic acid tetrakis (2,2,6
6-tetramethyl-4-piperidinyl) ester, poly [[6- (1,1,3,3-tetramethylenebutyl) imino-1,3,5-triazine-2,4-diyl]
[(2,2,6,6-Tetramethyl-4-piperidinyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidinyl) imino]], 1,2,
2,6,6-pentamethylpiperidine, dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate,
And N, N'-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,
2,6,6-Pentamethyl-4-piperidyl) amino]
-1,3,5-triazine condensate is mentioned, especially bis (2,2,6,6-tetramethyl-4-piperidinyl)
Sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, dimethyl succinate
1- (2-hydroxyethyl) -4-hydroxy-2,
2,6,6-tetramethylpiperidine polycondensate, N,
N'-bis (3-aminopropyl) ethylenediamine
2,4-bis [N-butyl-N- (1,2,2,6,6
-Pentamethyl-4-piperidyl) amino] -1,3,
The 5-triazine condensate is preferred.

The addition amount is oxymethylene copolymer 1
It is usually 0.001 to 5 parts by weight, preferably 0.01 to 3 parts by weight, relative to 00 parts by weight. When the amount is too small, the effect of improving the thermal stability of the oxymethylene copolymer is small, and when the amount is too large, the bleeding phenomenon is exhibited or the mechanical properties are deteriorated, which is not preferable.

The amount of water used in the present invention is usually 0.01 to 1 with respect to 100 parts by weight of oxymethylene copolymer.
It is 00 parts by weight. It is preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight. If the amount is too small, the effect of improving the thermal stability of the oxymethylene copolymer is small, and if the amount is too large, the production becomes difficult, which is not preferable.

The stabilizer used in the present invention is preferably a hindered phenol compound, specifically, 2,6
-Di-t-butyl-4-methylphenol, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,
6-hexanediol-bis [3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate],
Pentaerythrityl-tetrakis [3- (3,5-di-
t-Butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-t
-Butyl-4-hydroxyhydrocinnamamide), 2-
t-butyl-6- (3'-t-butyl-5'-methyl-
2'-hydroxybenzyl) -4-methylphenyl acrylate, 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl ] -2, 4, 8, 1
Examples thereof include 0-tetraoxaspiro [5,5] undecane. Among them, triethylene glycol-bis [3- (3-t-butyl-), which is a compound having a molecular weight of 400 or more,
5-methyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate] is particularly preferred. The amount added is usually 0.001 to 5 parts by weight, preferably 0.01 to 3 parts by weight, based on 100 parts by weight of the oxymethylene copolymer. If it is too small, the effect of improving the thermal stability of the oxymethylene copolymer is small, and if it is too large, the bleeding phenomenon is observed, which is not preferable.

In addition, when the oxymethylene copolymer of the present invention is added and blended with other heat stabilizer, the heat stability may be further improved. Such compounds include urethane compounds, pyridine derivatives, pyrrolidone derivatives, urea derivatives, triazine derivatives, hydrazine derivatives, amidine compounds, polyamide and polyamide copolymers, ethylene / vinyl alcohol copolymers, fatty acid metal salts, alkali metal water. Examples thereof include oxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkali metal carbonates. Specific examples include melamine, benzoguanamine, acetoguanamine, N-methylolmelamine, and N, N'-dimethylol. Melamine, N, N ′, N ″ -trimethylolmelamine, dicyandiamide, nylon 6, nylon 6/12
Copolymer, nylon 6/66/610 ternary copolymer, nylon 6/66/610/12 quaternary copolymer, calcium stearate, calcium 12-hydroxystearate, calcium hydroxide, magnesium hydroxide, sodium carbonate, etc. Is preferred. The amount of these heat stabilizers added is usually 0.
001 to 5 parts by weight, preferably 0.01 to 3 parts by weight. If it is too small, the effect of addition does not appear, and if it is too large, the bleeding phenomenon is observed, which is not preferable.

In addition, the composition of the present invention contains calcium carbonate, barium sulfate, clay, titanium oxide, silicon oxide, mica powder, fillers such as glass beads, carbon fiber, and glass as long as the effects of the present invention are not impaired. Reinforcing agents such as fibers, ceramic fibers, aramid fibers, potassium titanate fibers,
Colorants (pigments, dyes), nucleating agents, plasticizers, release agents such as ethylene bis-stearamide, polyethylene wax,
Conductive agents such as carbon black, benzophenone compounds, light stabilizers such as benzotriazole compounds,
Additives such as a pressure-sensitive adhesive, a lubricant, a hydrolysis resistance improver, and an adhesion aid can be optionally contained.

In the present invention, the temperature at which water is added together with the stabilizer and heated is required to be 100 ° C to 260 ° C, preferably 170 ° C to 260 ° C.

Examples will be described below, but the present invention is not limited thereto.

[0030]

The present invention will be described below with reference to examples. All percentages and parts in the examples are by weight.

The MI value, thermal decomposition rate K250, polymer melting point Tm, crystallization temperature Tc, and mechanical properties of the molded products shown in the examples and comparative examples were measured as follows.

Molding: Using an injection molding machine having a mold clamping pressure of 60 tons, a cylinder temperature of 190 ° C. and a mold temperature of 65.
The ASTM No. 1 dumbbell test piece and the Izod impact test piece were injection-molded at a setting temperature of 50 ° C. and a molding cycle of 50 seconds.

MI value: Using pellets dried in a hot air oven at 80 ° C. for 3 hours, the temperature was measured at 190 ° C. at a load of 2160 grams according to the ASTM D-1238 method.

Mechanical properties: AS obtained by the above injection molding
Using the TM1 dumbbell test piece, ASTM D-638
The tensile strength was measured according to the method, and the impact strength was measured according to the ASTM D-256 method using an Izod impact test piece.

Heat decomposition rate K250: K250 is 250 ° C
Means the decomposition rate when left to stand for a certain period of time. Using a thermobalance device, a sample of about 10 mg was placed under a nitrogen atmosphere.
It was left at 250 ° C. and measured. As the thermobalance device, TG / DTA200 manufactured by Seiko Instruments Inc. was used.

Polymer melting point Tm, crystallization temperature Tc: Using a differential scanning calorimeter, the temperature is raised at a heating rate of 10 ° C./min in a nitrogen atmosphere, and after measuring the polymer melting point Tm, 10 ° C. / The temperature was lowered in minutes, and the crystallization temperature Tc was measured.

In Examples and Comparative Examples, oxymethylene crude polymer (POM-1) produced by the following method was used.

.Oxymethylene crude polymer (POM-1)
Production of Biaxial extruder type polymerization machine (100 mmφ, cylinder length (L) / cylinder diameter (D) = 10.2) with trioxane (22.5 kg / h) and 1,3-dioxolane (70
0 g / h), and 100 ppm of boron trifluoride diethyl etherate (2.5% benzene solution) and 500 ppm of methylal were respectively fed to trioxane to carry out continuous polymerization. Polymerization was performed by controlling the outer jacket temperature to 60 ° C. and rotating at 100 rpm. Methylal as a molecular weight regulator was dissolved in trioxane. Further, a premixing zone was provided so that the 1,3-dioxolane and the catalyst solution were premixed immediately before being supplied to the kneader. Polymer as white fine powder 2
Obtained at 2.3 kg / h.

Examples 1 to 5 and Comparative Examples 1 and 2 To 5 kg of oxymethylene crude polymer (POM-1), various hindered amine compounds were added as a 15 to 20% benzene solution at a ratio shown in Table 1. The catalyst was deactivated by stirring in a Henschel mixer for 10 minutes. Water is added to this together with the stabilizer, and the Ikegai Iron Works with vent 2
Using a shaft 45 mmφ extruder, melt extrusion kneading was performed at a temperature of 220 ° C. and a vacuum degree of 10 mm torr at the vent portion. For comparison, deactivated with a polymer using alkali carbonate instead of hindered amine and hindered amine,
A polymer with no added water was prepared otherwise in a similar manner. The resulting polymer was extruded as strands and pelletized by a cutter. After drying the pellets at 80 ° C. for 5 hours in a hot air circulation oven, MI measurement,
The thermal decomposition rate was measured and molding was performed to measure the mechanical properties. The results are summarized in Table 2.

[0040]

[Table 1]

A-1: "Sanol" LS765 [manufactured by Sankyo Co., Ltd., bis (1,2,2,6,6-pentamethyl-
4-piperidinyl) sebacate] A-2: "Tinuvin" 622LD (manufactured by Ciba Geigy,
Dimethyl succinate 1- (2-hydroxyethyl) -4
-Hydroxy-2,2,6,6-tetramethylpiperidine polycondensate] A-3: "Chimasorb" 119FL [manufactured by Ciba-Geigy, N, N-bis (3-aminopropyl) ethylenediamine-2,4-bis] [N-butyl-N- (1,2,
2,6,6-Pentamethyl-4-piperidyl) amino]
-6-Chloro-1,3,5-triazine condensate] B-1: Sodium carbonate IR-245: [manufactured by Ciba Geigy, (triethylene glycol-bis [3- (3-t-butyl-5-methyl-
4-Hydroxyphenyl) propionate]]

[0042]

[Table 2]

It is clear from Table 2 that the polymer deactivated by using the hindered amine compound and the polymer added with the stabilizer and water is the one obtained by only deactivating the catalyst by using the hindered amine compound, and the alkali carbonate is used instead of the hindered amine compound. It is superior in thermal stability and mechanical properties to the existing ones. Further, the more the added amount of the hindered amine compound is, the more excellent the thermal stability is, and the thermal stability of the obtained polymer does not change even if the kind of the hindered amine is changed.

Examples 6 to 10 and Comparative Examples 3 and 4 In the same manner as in Example 1 except that the amount of water added, the type of stabilizer, and the temperature at the time of adding water together with the stabilizer were changed. Polymers were prepared and evaluated. The manufacturing conditions are shown in Table 3 and the evaluation results are shown in Table 4.

[0045]

[Table 3]

A-1: "Sanol" LS765 [manufactured by Sankyo Co., Ltd., bis (1,2,2,6,6-pentamethyl-
4-piperidinyl) sebacate] IR-245: [manufactured by Ciba Geigy, (triethylene glycol-bis [3- (3-t-butyl-5-methyl-
4-Hydroxyphenyl) propionate]] IR-1010: [Ciba Geigy, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4]
-Hydroxyphenyl) propionate]]

[0047]

[Table 4]

It is clear from Table 4 that the polymer obtained by the production method of the present invention has excellent thermal stability and mechanical properties.

[0049]

By using the production method of the present invention, it is possible to produce an oxymethylene copolymer having excellent thermal stability and mechanical properties.

Claims (2)

[Claims] 1. A mixture of trioxane and a cyclic ether is selected from the group 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 an oxymethylene copolymer containing an oxymethylene unit and another oxyalkylene unit is produced by polymerizing in the presence of at least one polymerization catalyst, the following general formula: (In the formula, R ¹ represents a hydrogen atom or a monovalent organic residue having 1 to 30 carbon atoms, and R ^{2 to} R ⁵ represent an alkyl group having 1 to ⁵ carbon atoms, and even if they are the same, N may be different from each other, n is an integer of 1 or more, and R ⁶ is an n-valent organic residue) to deactivate the boron trifluoride catalyst and then stabilize. A method for producing an oxymethylene copolymer, which comprises adding water together with an agent and heating the mixture in a temperature range of 100 ° C to 260 ° C. 2. The method for producing an oxymethylene copolymer according to claim 1, wherein a hindered phenol compound is used as a stabilizer.