JPH059249A - Production of oxymethylene copolymer - Google Patents

Abstract

PURPOSE:To produce the title copolymer excellent in thermal stability. etc., by copolymerizing trioxane with a cyclic ether in the presence of a catalyst, deactivating the catalyst with a hindered amine, adding a stabilizer, water, etc., to the polymn. system, and thermally treating the system. CONSTITUTION:Trioxane is copolymerized with a cyclic ether (e.g. ethylene oxide) in the presence of a polymn. catalyst selected from the group consisting of boron trifluoride and a coordination compd. of boron trifluoride with an organic oxygen or sulfur compd. (e. g. boron trifluride diethyl etherate), thereby giving a copolymer comprising oxymethylene units and other oxyalkylene units. After the completion of copolymn., a hindered amine of the formula (wherein R<1> is H or a 1-30C monovalent org. group; R<2> to R<5> are each 1-5C alkyl; n is 1 or higher; and R<6> is an n-valent org. group) is added to the copolymn. system to deactivate the catalyst, then a stabilizer, water, and an alkali or alkaline earth metal salt are added to the system, and the system is thermally treated at 100-260 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of producing a oxymethylene copolymer by polymerizing trioxane and a cyclic ether in the presence of a catalyst, adding a hindered amine compound after the completion of the polymerization to deactivate the catalyst, and then adding a stabilizer. A method for producing an oxymethylene copolymer which is excellent in thermal stability and mechanical properties by adding water together with an alkali metal salt or an alkaline earth metal salt and heating the mixture and which has little odor during melt molding Is.

[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.

It is an object of the present inventors to solve the above problems and 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. N may be an integer of 1 or more and R ⁶ represents an n-valent organic residue) to deactivate the polymerization catalyst by adding a hindered amine compound represented by
Water is added together with a stabilizer, and then an alkali metal salt or an alkaline earth metal salt is added, 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.

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 needs to be in the range of 0.1 to 10 mol%, preferably 0.2 to 6 mol% based on the oxymethylene unit, and if it is too small, the thermal stability of the obtained polymer is low. ,
On the other hand, if the amount is too large, the mechanical strength and the moldability are deteriorated, which is not preferable.

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.

Although various apparatuses for polymerizing trioxane alone or trioxane and a cyclic ether in a bulk are known, the polymerization of the present invention is not particularly limited by the apparatus, 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 bulk polymerization, an apparatus having a strong stirring ability and controllable reaction temperature is preferably used because rapid solidification and heat generation during polymerization occur.

As the bulk polymerization apparatus of the present invention having such performance, a kneader having a sigma type stirring blade, a cylindrical parel as a reaction zone, and a screw having a large number of interrupted ridges coaxially in the parel are used. A mixer that operates so that the interrupted portion and teeth protruding from the inner surface of the parell mesh with each other; a conventional 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 beginning of the polymerization, the temperature in the polymerization reaction device tends to rise due to the reaction heat or the frictional heat caused by solidification. Therefore, control the reaction temperature by passing cooling water through the jacket. Is desirable.

The hindered amine compound that 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 is representatively represented by bis (2,2,6). 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 should be 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 must be 0.01 to 100 parts by weight based on 100 parts by weight of oxymethylene copolymer. 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 alkali metal salts or alkaline earth metal salts used in the present invention include alkali metal or alkaline earth metal hydroxides, carbonates, bicarbonates, phosphates, borates, silicates and the like. Inorganic acid salts, acetates, oxalates, formates, benzoates, terephthalates, isophthalates, phthalates, organic salts such as fatty acid salts, methoxides, ethoxides, n-butoxides, sec-butoxides Examples thereof include alkoxides such as tert-butoxide, and phenoxides. Among them, hydroxides, carbonates, acetates, and fatty acid salts are preferably used.

Examples of the alkali metal or alkaline earth metal include lithium, sodium, potassium, cesium, magnesium, calcium, strontium, barium and the like, among which lithium, sodium, potassium, magnesium and calcium are preferably used.

Specifically, calcium hydroxide, magnesium hydroxide, sodium carbonate, calcium acetate, calcium stearate, 12-hydroxy calcium stearate and the like are particularly preferable.

In the present invention, one or more of the above-mentioned alkali metal salts and alkaline earth metal salts are added. The addition amount is usually 0.001 to 5 parts by weight with respect to 100 parts by weight of oxymethylene copolymer, and 0.005 to
2 parts by weight is preferred. 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 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
0-tetraoxaspiro [5,5] undecane and the like can be mentioned. 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.

Further, the thermal stability may be further improved by adding / blending other thermal stabilizer to the polyoxymethylene copolymer of the present invention. Such compounds include:
Urethane compound, pyridine derivative, pyrrolidone derivative,
Examples thereof include urea derivatives, triazine derivatives, hydrazine derivatives, amidine compounds, polyamides and polyamide copolymers, ethylene / vinyl alcohol copolymers, and specifically, melamine, benzoguanamine, acetoguanamine, N-methylolmelamine, N, N. '-Dimethylol melamine, N, N', N ''-trimethylol melamine, dicyandiamide, nylon 6, nylon 6/12
Copolymers, nylon 6/66/610 ternary copolymers, nylon 6/66/610/12 quaternary copolymers and the like are preferred. The amount of these heat stabilizers added is usually 0.001 to 5 parts by weight per 100 parts by weight of oxymethylene copolymer,
It is preferably 0.01 to 3 parts by weight. If the amount 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.

Further, 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 the stabilizer, water and the alkali metal salt or alkaline earth metal salt are added and heated is required to be 100 ° C to 260 ° C, preferably 170 ° C to 260 ° C. It is a range.

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

[0033]

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 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. At this time, the odor of the molded product was evaluated in three grades of ◯: almost no, Δ: moderately strong, and x: strong.

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

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.

Thermal 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 11, Comparative Examples 1 and 2 Various types of hindered amine compounds were added as benzene solutions of 15 to 20% to 5 kg of oxymethylene crude polymer (POM-1) at the ratios shown in Table 1. The catalyst was deactivated by stirring in a Henschel mixer for 10 minutes. Water and various alkali metal salts or alkaline earth metal salts are added to this together with a stabilizer, and the mixture is melted at a temperature of 220 ° C. and a vacuum degree of 10 mm torr at a vent part using a biaxial 45 mmφ extruder with a vent manufactured by Ikegai Iron Works. Extruded and kneaded. For comparison, a polymer using alkali carbonate instead of hindered amine and a polymer deactivated with hindered amine but not added with water and an alkali metal salt or an alkaline earth metal salt were produced by the same method. The resulting polymer was extruded as strands and pelletized by a cutter. After drying the pellets in a hot air circulation oven at 80 ° C. for 5 hours, MI measurement, thermal decomposition rate measurement, and molding were performed to measure mechanical properties. The results are summarized in Table 2.

[0043]

[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: calcium stearate B-2: 12-calcium hydroxystearate B-3: sodium carbonate B-4: calcium hydroxide B-5: magnesium hydroxide IR-245: [manufactured by Ciba Geigy, (triethylene glycol-bis [3- (3-t-butyl-5-methyl-
4-Hydroxyphenyl) propionate]]

[0045]

[Table 2]

Odor at the time of molding ◯: Almost none Δ: Slightly strong ×: Strong It is clear from Table 2 that the polymer deactivated by using the hindered amine compound and added with water and an alkali metal salt or an alkaline earth metal salt is It is superior in thermal stability and mechanical properties, and has less odor during melt-molding, as compared with those obtained by only deactivating the catalyst with a hindered amine compound and those obtained by using an alkali carbonate in place of the hindered amine compound. 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. Further, the larger the amount of the alkali metal salt or alkaline earth metal salt added, the more excellent the thermal stability is, and the thermal stability of the obtained polymer does not change even if the kind thereof is changed.

Examples 12 to 16 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 when water was added 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.

[0048]

[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]] B-1: calcium stearate

[0050]

[Table 4]

Odor during molding ○: Almost none △: Slightly strong ×: Strong From Table 4, it is clear that the polymer obtained by the production method of the present invention has excellent thermal stability and mechanical properties, and has little odor during molding. Is clear.

[0052]

EFFECTS OF THE INVENTION By using the production method of the present invention, it is possible to produce an oxymethylene copolymer which is excellent in thermal stability and mechanical properties and has little odor during molding.

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 an integer of 1 or more, R ⁶ is an n-valent organic residue) to deactivate the polymerization catalyst, and then water is added together with the stabilizer. Is further added, and an alkali metal salt or an alkaline earth metal salt is further added, and the mixture is heated in a temperature range of 100 ° C. to 260 ° C. for producing an oxymethylene copolymer. 2. The method for producing an oxymethylene copolymer according to claim 1, wherein a hindered phenol compound is used as a stabilizer.