JP3130469B2 - Method for producing polyacetal copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyacetal copolymer. Specifically, in a copolymerization with trioxane as a main monomer and a co-monomer that can be copolymerized with trioxane, a specific non-volatile protonic acid is used as a polymerization catalyst, polymerization is carried out to a specific polymerization rate, and then trifluorine is further added. By adding boron halide or its coordination compound and continuing the polymerization reaction, a simple process, in a high yield, and producing a polyacetal polymer or copolymer excellent in quality such as thermal stability. It is about the method.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a polyacetal copolymer, a cationic copolymerization using trioxane or trioxane as a main monomer and a cyclic ether or cyclic formal having two or more adjacent carbon atoms as a comonomer has been known. The cationic active catalyst used in these copolymers, Lewis acids, especially boron, tin, titanium,
Phosphorus, arsenic and antimony halides, such as boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentachloride, phosphorus pentafluoride, arsenic pentafluoride and antimony pentafluoride, and complex compounds or salts thereof Compounds or protic acids such as perfluoroalkylsulfonic acid, perchloric acid, or esters of these protic acids, especially esters of perchloric acid with lower aliphatic alcohols, such as perchloric acid-tertiary butyl ester, anhydrides of protic acids Mixed anhydrides of perchloric acid and lower aliphatic carboxylic acids, in particular acetyl perchlorate, or also trimethyloxonium hexafluorophosphate, triphenylmethylhexafluoroarsenate, acetyltetrafluoroborate, acetylhexayl Fluorophosphate and acetylhexaf Ol ARUZE diisocyanate and the like have been proposed. Above all, boron trifluoride or a coordination compound of boron trifluoride and an organic compound, for example, ethers, is the most common polymerization catalyst containing trioxane as a main monomer, and is widely used industrially. However, conventionally used polymerization catalysts such as boron trifluoride-based compounds have both an extremely high polymerization yield and high quality such as thermal stability and molecular weight based on the formation of unstable portions of the resulting crude polymer. It was very difficult to satisfy both. That is, in the case of a conventionally used polymerization catalyst such as a boron trifluoride compound, the polymerization rate is increased by using a large amount thereof, and a relatively high polymerization yield can be obtained in a short time. The quality of the resulting crude polymer is not satisfactory, and a complicated stabilization step is required in the subsequent step, which is not economically preferable. If the amount of the catalyst is reduced, the above quality is improved, but it takes an extremely long time to obtain a high yield, which is not preferable in terms of production efficiency. On the other hand, protonic acid generally has a high polymerization activity, the polymerization rate is high even in a very small amount, a fixed polymerization yield is quickly reached, and a stable polyacetal copolymer is formed. Possibly due to insufficient action on the volatilizing monomer or at the end of polymerization, for example 90
% Or more, especially 95% or more, the polymerization rate sharply decreases, and it is very difficult to obtain a polymerization yield close to 100% in a short time.

[0003]

In view of the above situation, the present inventors have obtained an extremely high polymerization yield in a relatively short time and obtained a high-quality crude polymer having few unstable parts, It is an object of the present invention to produce a polyacetal copolymer which is extremely stable thermally even by a simple process.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a polymerization catalyst and a method of adding the same in order to achieve the above object, and as a result, using a specific non-volatile protonic acid as a catalyst to a specific polymerization rate. After the addition, a volatile cation-active catalyst such as boron trifluoride or a coordination compound thereof is further added to carry out copolymerization, thereby promoting the late or final stage of the polymerization reaction, and With high polymerization yield,
In addition, they have found that a high quality crude polymer can be obtained and that the above object can be achieved, and the present invention has been completed. That is, the present invention is based on trioxane as a main monomer, when producing a polyacetal copolymer by copolymerization with a cyclic ether or cyclic formal having at least one carbon bond as a comonomer, a heteropolyacid or an acid salt thereof as a polymerization catalyst , At least one non-volatile proton acid catalyst selected from isopoly acids or acid salts thereof (A)
After performing polymerization until the polymerization rate reaches 60 to 90% (based on the total supplied monomers), as a second polymerization catalyst,
This is a method for producing a polyacetal copolymer, which comprises adding boron trifluoride or its coordination compound (B) to carry out polymerization, and then adding a catalyst deactivator to deactivate the resultant.

That is, the feature of the present invention is that the specific (A),
(B) The two types of polymerization catalysts are used separately and added separately. By performing the initial polymerization reaction (up to a polymerization rate of 60 to 90%) using a specific protonic acid catalyst (A), Due to the extremely high polymerization activity peculiar to the catalyst (A), it is possible to reach a certain degree of polymerization in a very small amount in a short period of time and to suppress undesired side reactions such as a decomposition reaction during that time. By adding the catalyst (B) and continuing the polymerization reaction, by compensating for a rapid decrease in the polymerization rate in the latter or final stage of the polymerization, and by balancing the polymerization rate throughout the entire polymerization process, a short time is obtained. At 100%
In this method, the amount of the catalyst (B) to be added in the latter stage is extremely small.
In particular, the decomposition at the late or late stage of the polymerization, in which the decomposition reaction becomes relatively dominant, can be kept small, and as a whole the polymerization reaction,
A high-polymerization yield close to 100% is obtained in a short time, and a high-quality crude polymer with a high molecular weight and few unstable parts is obtained. The post-treatment step can be extremely simplified without the need for a post-step, and a high quality polymer can be obtained economically.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below. First, in the present invention, the non-volatile proton acid catalyst (A) to be added and used at the beginning of the polymerization reaction is at least one or more selected from heteropoly acids or acid salts thereof, isopoly acids or acid salts thereof. The heteropolyacid of the polymerization catalyst (A) is a general term for polyacids formed by the dehydration condensation of different oxyacids, where a specific heterogeneous element is present at the center and the condensed acid group condenses by sharing an oxygen atom. It has a mononuclear or polynuclear complex ion. Such a heteronuclear condensed acid can be generally represented by the general formula (1).

[0007]

Embedded image

The heteropolyacid particularly effective as the polymerization catalyst (A) of the present invention is such that the central element (M) in the above composition formula is composed of at least one element selected from P and Si,
Further, this is the case where the coordinating element (M ') is composed of at least one element selected from W, Mo and V (particularly preferably W and Mo). Further, an acidic salt in which Hx in the formula (1) is partially replaced with various metals can also be used as the catalyst (A) of the present invention. Specific examples of these heteropolyacids include phosphomolybdic acid, phosphotungstic acid, phosphomolybdotungstic acid, phosphomolybdovanadic acid, phosphomolybdung tungstovanadic acid, phosphorus tungstovanadic acid, silicotungstic acid, silicomolybdic acid, silicic acid Molybdung tungstic acid, silico-molybdung tovanadic acid, and the like. Among them, preferred are silicomolybdic acid, silicotungstic acid, phosphomolybdic acid, phosphotungstic acid and the like. Further, the heteropoly acid is generally α
₀ type, beta _II type, but beta _IV type are known, the point at alpha ₀ type polymerization activity, beta _IV type are preferable, particularly preferably alpha ₀ type.

The isopolyacid of the polymerization catalyst (A) is also called isopolyacid, homonuclear condensed acid or homopolyacid, and is a single metal represented by the following general formula (2) or (3). It is a high molecular weight inorganic oxyacid comprising a condensate of the inorganic oxyacid. ^{_{xM I 2 O · pM V 2}} O 5 · yH 2 O (2) xM I 2 O · pM VI O 3 · yH 2 O (3) [where, M ^I is hydrogen, M ^V periodic table group V V, Nb or
Ta and M ^VI are Cr, Mo, W or U in the group ^VI of the periodic table, p is an integer of 1 or more, x is an integer of 1 or more, and y is a number of 0 to 50. The isopoly acid is obtained by treating a salt solution of an isopoly acid salt corresponding to the above formulas (2) and (3), for example, isopolymolybdate, isopolytungstate, isopolyvanadate with an ion exchange resin. It is a protonic acid prepared by various methods such as a method and a method of adding a mineral acid to a concentrated solution and extracting with ether. Further, acidic salts in which protons (M ^I ; hydrogen) of these acids are partially replaced by various metals can also be used for the catalyst of the present invention. Especially (3)
Preferred are the isopoly acids of the formula or acid salts thereof. Specific examples of these isopoly acids include, for example, paratungstic acid,
Isopolytungstic acid such as metatungstic acid,
Isopolymolybdic acid such as paramolybdic acid, metamolybdic acid and the like, isopolyvanadate, and the like.
Among them, isopolytungstic acid is preferable.

The above-mentioned protonic acid catalyst (A) is preferably diluted with a solvent which does not adversely affect the polymerization and added to the monomer, and used for uniform reaction. An inert organic solvent in which (A) is soluble, for example, ethers (eg, n-butyl ether) can be used, but is not limited thereto, and may be used as a chain transfer agent for controlling the molecular weight as described below. The used linear acetal (eg, methylal) and alcohol (eg, methanol) can also be used as a diluent. These diluents can be used without much trouble since their usage is extremely small relative to the monomer. . It is also possible to dissolve in part or all of the comonomer as described below and add it together with the comonomer, which is preferable in that no other solvent is mixed, but in this case, until the comonomer is added to the polymerization system and mixed. In order to prevent homopolymerization, it is desirable to cool sufficiently and keep the temperature as low as possible, at least below room temperature, just before adding to the polymerization system.
The protonic acid catalyst (A) used as a polymerization catalyst in the early stage of the polymerization has a very high polymerization activity, so that only a small amount is sufficient, and generally the amount of the monomer is to be polymerized.
0.1 to 50 ppm, preferably 0.5 to 20 ppm,
Particularly preferably, it is 0.5 to 10 ppm.

In the present invention, the catalyst (B) is added when the rate of polymerization in the former stage by the catalyst (A) decreases. Catalyst (B)
The timing of the addition of
0-90%, preferably 65-85%, particularly preferably 70-85
%, And may be appropriately selected within the range, and the standard is easily selected by preliminary experiments. The polymerization catalyst (B) added in the latter stage is boron trifluoride or its coordination compound, and is used as a gaseous, liquid or solution of a suitable organic solvent. Particularly preferred is boron trifluoride. As the organic compound forming the coordination compound,
Alcohol, ether, sulfide and the like can be mentioned. Among them, the coordination compound is preferably a complex with an ether such as a boron trifluoride diethyl ether complex and a boron trifluoride di (n-butyl) ether complex. In the case of a coordination compound, it is preferable to add the compound after diluting it with an organic solvent for dilution, for example, cyclohexane, aliphatic hydrocarbons such as n-hexane, bemben, aromatic hydrocarbons such as toluene, dichloromethane, 1,1, and the like. Halogenated hydrocarbons such as 2-dichloroethane are commonly used. A relatively small amount of boron trifluoride or its coordination compound (B) to be added and used in the latter stage of the above polymerization reaction is sufficient, and 3 to 50 ppm (as boron trifluoride) based on the total amount of the monomers used. Weight basis), preferably 5 to 40 ppm, particularly preferably 5 to 30 ppm. Further, when the catalyst (B) is added and the process proceeds to the subsequent polymerization reaction, a comonomer as described later may be added in order to adjust the copolymerization component distribution of the produced copolymer.

As the main monomer of the present invention, trioxane which is a cyclic trimer of formaldehyde is used.
The comonomer used in the present invention is a cyclic ether or cyclic formal having at least one adjacent carbon-carbon bond, and any known comonomer used for copolymerization with conventional trioxane can be used. Examples of such a cyclic ether or cyclic formal include 1,3-dioxolan, diethylene glycol formal, 1,4-
Cyclic compounds such as butanediol formal, 1,3-dioxane, ethylene oxide, propylene oxide, and epichlorohydrin. Further, a cyclic ether or cyclic formal having an unsaturated bonding group is also used. Furthermore, as a comonomer for the copolymer to form a branched or crosslinked molecular structure, a compound having two or more cyclic ether groups or cyclic formal groups, for example, butanediol diglycidyl ether, butanediol dimethylidene glyceryl Alkylene-diglycidyl ethers such as ethers or diformals can also be used. These comonomers may be used in combination of two or more depending on the purpose. Particularly preferred comonomers include cyclic ethers and cyclic formals such as 1,3-dioxolan, diethylene glycol formal, 1,4-butanediol formal and ethylene oxide. The amount of the comonomer used in the present invention is from 0.1 to 20 mol%, preferably from 0.2 to 10 mol%, based on trioxane. If the amount of the comonomer is too small, the unstable terminal portion increases and the stability deteriorates. If the amount is too large, the produced copolymer becomes soft and the melting point is lowered, which is not preferable. As described above, a part or all of the comonomer may be used also as a diluent for the protonic acid catalyst (A).

In the polymerization method of the present invention, a known chain transfer agent, for example, a low-molecular-weight linear acetal such as methylal, an alcohol, an ester, etc., may be added to adjust the degree of polymerization according to the purpose. It is. This may also be used as a diluent for the catalyst (A). The polymerization reaction system is desirably substantially free of impurities having active hydrogen, for example, formic acid, water, and the like. For example, each is preferably at most 30 ppm, more preferably at most 20 ppm, particularly preferably at most 10 ppm.

The polymerization method of the present invention can be carried out with the same equipment and method as in the conventionally known trioxane copolymerization.
That is, any of a batch type and a continuous type is possible, and a method of using a liquid monomer and obtaining a polymer in the form of a solid powder as the polymerization proceeds is general. As the polymerization apparatus used in the present invention, a batch-type reaction vessel with a commonly used temperature-controllable stirrer can be used.
A co-kneader, a twin-screw type continuous extrusion mixer, a twin-screw paddle type continuous mixer, and other continuous polymerization devices such as trioxane proposed so far can be used, but the polymerization is completed with a single device. For this purpose, it is necessary to provide a catalyst (B) addition hole at an appropriate position. In order to carry out the present invention, a preferred embodiment of a continuous polymerization apparatus is to use at least two or more polymerization apparatuses and to conduct polymerization up to a polymerization rate of 60 to 90% using a proton acid catalyst (A) in a preceding polymerization apparatus. This is a method in which the polymerization is transferred to the subsequent polymerization apparatus, where the polymerization catalyst (B) is added, and the polymerization is further continued. In this case, each polymerization apparatus to be used may be appropriately selected. That is, the polymerization apparatus described above may be connected in two stages. However, in the previous stage of polymerization, since the liquid monomer rapidly becomes a powdery solid, a self-cleaning continuous type having a temperature control and a stirring / pulverizing function is provided. It is preferable to use a combination of a polymerization machine and a polymerization apparatus provided at the subsequent stage, which is equipped with a temperature control mechanism and a surface renewal and stirring function of the powdery mass, and uses a device that slowly advances. still,
It is also a preferable embodiment to pulverize once through a suitable pulverizer between the front and rear reactors and then transfer to the subsequent reactor.
The polymerization is carried out at a temperature in the range of 60 to 120 ° C, preferably 65 to 110 ° C, throughout the preceding and subsequent stages.

Next, in the present invention, a catalyst deactivator is added to the copolymerization reaction product to deactivate the catalyst. Regarding the method of catalyst deactivation, of course, a method using a known relatively large amount of a basic solution is also possible, and the effects of the present invention are exhibited, and a high-quality crude polymer can be obtained with a high polymerization yield. But,
In the present invention, the conversion of the monomer is extremely high in a relatively short polymerization time, so that the amount of the unreacted monomer can be reduced to at least 5% by weight, generally 3% by weight or less, further 2% by weight or less. Since the amount of unstable portions of the resulting crude copolymer is small, the catalyst is deactivated with a small amount of deactivator as described below without washing and monomer recovery of the produced crude polymer, and then heated and melted as it is. By performing the treatment, a polyacetal copolymer having high heat stability can be easily obtained. That is, the deactivation treatment of the catalyst of the present invention may be carried out by contacting the polymerization product with a basic gas or by adding a small amount (for example, 7% by weight or less, further 5% by weight or less based on the produced polymer) containing a basic compound. Is achieved by adding and mixing.

Examples of the basic gas used in the deactivation treatment of the present invention include ammonia and / or an amine compound, and a mixed gas of both is also preferably used. In this case, the amine compound is preferably a compound having a low molecular weight and a low boiling point, and preferably having a boiling point of 150 ° C. or lower, in order to contact the resulting crude polymer in a gaseous state. That is, the general formula R ₁ NH ₂ , R ₁ R ₂
Compounds represented by NH and R ₁ R ₂ R ₃ N (wherein R ₁ , R ₂ , R ₃ are an alkyl group or an alcohol group having 4 or less carbon atoms, preferably 2 or less carbon atoms) are preferable, and as described below. By diluting with a carrier gas, it is possible to make gaseous contact even with amines having a relatively high boiling point. Specific examples of such amine compounds include, for example, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, butylamine, dibutylamine, tributylamine, and the corresponding alcohol amines (such as trimethanolamine). Among them, methylamine, dimethylamine and trimethylamine are particularly preferred. The basic gas may be used as it is in a gaseous state, or may be brought into contact with the produced polymer using a mixed gas diluted with another carrier gas. The carrier gas is not particularly limited, but is preferably an inert gas, such as a nitrogen gas or another organic gas. The method of contacting the basic gas with the produced crude polymer is not particularly limited as long as the basic gas is in sufficient contact with the produced copolymer particles. For example, a method of stirring and mixing a crude polymer well in an atmosphere of a basic gas, or a method of blowing a basic gas in opposition to a flow of a crude copolymer, a method of circulating and flowing between particles of a crude polymer layer, Either can be applied. The amount of the basic gas in the present invention may be an amount sufficient to neutralize and deactivate the catalyst, and is preferably at least 10 times the molar amount of the normally used catalyst.

In the present invention, it is also possible to use a small amount of a solution or dispersion containing various basic compounds as a deactivator. The amount of the basic compound may be an amount sufficient to neutralize and deactivate the catalyst, and it is preferable to add the deactivator as a deactivator solution dissolved or dispersed in water or an organic solvent. In this case, the amount of the quencher solution added is
0.3 to 7% by weight, preferably 0.5 to 7% by weight based on the produced crude polymer
5% by weight. Even in such a small amount, the catalyst can be sufficiently deactivated by being sufficiently stirred and mixed with the crude polymer in combination with the characteristics of the polymerization catalyst used in the present invention.
As the quenching agent used in this method, any known basic substance is effective, and examples thereof include ammonia, various amine compounds, or oxides, hydroxides, organic acid salts of alkali or alkaline earth metals, or organic acid salts. Inorganic acid salts, trivalent phosphorus compounds, and the like can be mentioned, and it is also a preferable method to use two or more of these. As amine compounds, primary, secondary,
Tertiary aliphatic amines and aromatic amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, butylamine, dibutylamine, tributylamine and the corresponding alcohol amines (such as triethanolamine); Examples include aniline, diphenylamine, heterocyclic amine, and hindered amine (various piperidine derivatives). Further, as the alkali or alkaline earth metal compound, an alkali or alkaline earth metal oxide,
Inorganic weak acid salts such as hydroxides, carbonates, bicarbonates, phosphates, borates, silicates, acetates, oxalates, formates, benzoates, terephthalates, isophthalates, Phthalates, organic acid salts such as fatty acid salts, methoxide, ethoxide, n-butoxide, sec-butoxide, alkoxides such as tert-butoxide, phenoxide and the like, among which hydroxides, carbonates, fatty acid salts. It is preferably used. Here, examples of the alkali or alkaline earth metal component include lithium, sodium, potassium, cesium, magnesium, calcium, strontium, barium and the like, and among them, lithium, sodium, potassium, magnesium and calcium are preferably used. Specifically, calcium hydroxide, magnesium hydroxide, sodium carbonate, calcium acetate, calcium stearate, calcium hydroxystearate and the like are particularly preferred. Water or an organic solvent is used as a solvent for preparing the quenching agent. Methanol as an organic solvent,
Examples thereof include alcohols such as ethanol, ketones such as ethyl ketone and acetone, aromatic compounds such as benzene, toluene and xylene, and saturated hydrocarbons such as cyclohexane, n-hexane and n-heptane. Particularly preferred is an aqueous solution. The method of adding the deactivator solution to the crude polymer is not particularly limited, but it is preferable to spray the solution onto the crude polymer or to mix well with the solution after the addition of the solution in order to effect the dispersion contact effectively.

As described above, when a small amount of a solution containing a basic gas or a basic compound is used as a catalyst deactivator, and this is added to the resulting crude polymer to deactivate the catalyst, the coarse polymer becomes fine. It is preferable that the reaction product has a function of sufficiently pulverizing a bulk polymer, and that the polymerization reaction product is deactivated after the reaction product after polymerization is separately pulverized using a pulverizer. An agent may be added, and pulverization and stirring may be performed simultaneously in the presence of a quencher. The particle size of the crude polymer in the deactivation treatment is 3 mm at least 90% or more.
The particle size is preferably 2 mm or less, more preferably 1 mm or less. Deactivation treatment temperature is 0 to 140 ° C
And preferably 20 to 120 ° C.

In the present invention, the crude polymer to which a catalyst deactivator has been added can be subjected to heat melting treatment as it is.
The heat melting treatment is preferably performed in the presence of a stabilizer.
The stabilizer may be added and mixed at any time after the polymerization and before the heating and melting treatment, and may be added simultaneously with the deactivator, or may be added during the heating and melting treatment. In a preferred embodiment, the heat-melting treatment is carried out by adding a small amount (for example, 0.1 to 7% by weight) of water. As a stabilizer, it is important to add a substance known as a stabilizer of a conventional polyacetal resin, for example, various hindered phenolic antioxidants, etc., and various nitrogen-containing compounds, metal oxides and fatty acid salts. And the like are preferably used in combination.

For example, hindered phenolic antioxidants include 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], tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, N, N'-hexamethylene Bis (3,5-di-tert-butyl-4-hydroxyhydrocinnamide), 2-tert-butyl-6- (3'-tert-butyl-5'-methyl-2'-hydroxybenzyl) -4- Methylphenyl acrylate, 3,9 −
Bis [2-{(3-t-butyl-4-hydroxy-5-
Methylphenyl) propionyloxy {-1,1'-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] -undecane. Examples of the nitrogen-containing compound include dicyandiamide, melamine or a derivative thereof, urea or a derivative thereof, a benzotriazole-based compound, a piperidine-based compound (hindered amine), various polyamides or copolymers thereof (for example, nylon 6, 12, 6 / 12,
6/66/610, 6/66/610/12).
The metal oxide is preferably an oxide of an alkaline earth metal, and the metal fatty acid salt is, for example, a calcium salt or a magnesium salt of a higher fatty acid. Since these stabilizers have different functions, it is preferable to appropriately select and use two or more of them in accordance with the purpose. Further, at this stage, if necessary, various other additives such as a filler such as glass fiber, a crystallization accelerator (nucleating agent), and a release agent may be added and blended.

The heating and melting treatment in the present invention is preferably carried out in a temperature range from the melting point of the produced copolymer to 250 ° C., and particularly preferably in a temperature range from the melting point to 230 ° C. 250
If the temperature is higher than ℃, the polymer is decomposed and deteriorated, which is not preferable. Although there is no particular limitation on the heating and melting treatment apparatus, it is necessary to have a function of kneading the molten polymer and a function of venting, for example, a uniaxial or multiaxial continuous having at least one vent hole. Extrusion kneaders, co-kneaders and the like can be mentioned.

In the present invention, the melt-kneading treatment further deactivates the polymerization catalyst completely, and the mixed deactivator promotes the decomposition and elimination of the unstable terminal portion of the crude copolymer. And is removed from the vent together with other volatile substances,
Stable pellets of the polyacetal copolymer can be obtained. For this purpose, it is natural that it is preferable to reduce the pressure in the vent hole and to perform suction.

[0023]

EXAMPLES Examples of the present invention will be described below, but it is needless to say that the present invention is not limited to these examples. The terms and measuring methods in Examples and Comparative Examples are as follows. % Or ppm: All are expressed by weight. Polymerization rate: A part of the obtained product after the polymerization reaction is collected, washed with a deactivator solution, dried, and shown as a percentage of the obtained product of the polymer. Melt index (MI): Shows the melt index (g / 10min) measured at 190 ° C. This was evaluated as a characteristic value corresponding to the molecular weight. That is, the lower the MI, the higher the molecular weight. However, a stabilizer was mixed for the crude polymer in the above conversion measurement, and a pellet after melt extrusion was measured as it was. -Decomposition rate of alkali (existence of unstable part): 1 g of ground flakes of copolymer flakes or copolymer pellets is 100 ml of 50% methanol aqueous solution containing 0.5% ammonium hydroxide
After heating at 180 ° C. for 45 minutes in a closed container, the amount of formaldehyde decomposed and eluted in the solution is quantitatively analyzed, and the result is shown as% of the polymer. Heating weight loss rate: 5 g of copolymer flakes (mixed with stabilizer powder) or copolymer pellets at 230 ° C. in air
The weight loss rate when heated for 45 minutes is shown.

Examples 1 to 7 and Comparative Examples 1 to 3 A barrel having a jacket in which two circles partially overlap each other and through which a heat (cooling) medium is passed, and a plurality of stirring and propulsion barrels inside the jacket. Using a continuous mixing reactor provided with two rotating shafts with paddles in the longitudinal direction, hot water of 70 ° C. was passed through the jacket, and the two rotating shafts were rotated at a constant speed. Trioxane containing 2.5% of the comonomer shown in Table 1 and 700 ppm of methylal as a chain transfer agent was continuously supplied, and at the same time, the heteropolyacid or isopolyacid catalyst (A) shown in Table 1 was added to Table 1 for all monomers. Copolymerization was carried out by continuous addition to the indicated amount (average residence time: about 5 minutes). The catalyst (A) was previously dissolved in a comonomer (about 1% based on trioxane) and added as a solution kept at about 0 ° C. Next, the reaction product discharged from the polymerization machine discharge port (the intermediate polymerization rate is shown in Table 1) was introduced into a continuous mixing reaction apparatus having a second stirring, propelling, and scraping function, and at the same time, BF was added. ₃ as shown in Table 1
The reaction was continued at 80 ° C. for 25 minutes to determine the degree of polymerization of the product,
Further, the melt index, alkali decomposition rate, and heating weight reduction rate of the crude polymer were determined. Table 1 shows the results. For comparison, polymerization was carried out in the same manner when the catalyst addition conditions were changed as shown in Table 1. The results are shown in Table 1 (Comparative Examples 1 to 3). On the other hand, when the reaction product (Example 2, Example 5, and Comparative Examples 1 to 3) discharged from the second-stage reaction apparatus is pulverized through a pulverizer (90% or more has a particle size of 2 mm or less). At the same time, a basic gas or a basic compound solution shown in Table 2 was added as a deactivator, and the mixture was stirred at 80 ° C. for 30 minutes. Then, tetrakis- [methylene-3- (3,5-di-tert-butyl-4-) was used as a stabilizer.
[Hydroxyphenyl) propionate] 0.5% methane and 0.2% melamine are added and mixed in a Henschel mixer.
After stirring and mixing for about 1 minute, the mixture was melt-kneaded using a vented twin-screw extruder at a temperature of 210 ° C. and a degree of vacuum of 5 mmHg at the vent, and extruded to produce pellets. After drying the pellets, the properties of the polymer were measured. Table 2 shows the results. The catalyst (A) used is as follows. Heteropolyacid (HPA) HPA-1; phosphomolybdic acid HPA-2; silicotungstic acid HPA-3; phosphotungstic acid isopolyacid (IPA) IPA-1; paratungstic acid IPA-2; metatungstic acid

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

As is clear from the above description and the examples, according to the manufacturing method of the present invention, compared with the conventional method,
By a simple process, a high-yield polyacetal copolymer excellent in quality such as thermal stability can be produced.

──────────────────────────────────────────────────続 き Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 2/00-2/18

Claims (16)

(57) [Claims] 1. A method for producing a polyacetal copolymer by using trioxane as a main monomer and copolymerizing with a cyclic ether or cyclic formal having at least one carbon-carbon bond as a comonomer,
Using at least one kind of non-volatile proton acid catalyst (A) selected from heteropoly acids or their acid salts, isopoly acids or their acid salts, until the polymerization rate reaches 60 to 90% (based on the total monomers fed). After the polymerization, boron trifluoride or its coordination compound (B) is added as a second polymerization catalyst to carry out further polymerization, and then a catalyst deactivator is added for deactivation treatment. A method for producing a polyacetal copolymer. 2. The method for producing a polyacetal copolymer according to claim 1, wherein the heteropolyacid of the nonvolatile proton acid catalyst (A) or an acidic salt thereof is represented by the following general formula (1). Embedded image 3. The heteropolyacid or an acid salt thereof is phosphomolybdic acid, phosphotungstic acid, phosphomolybdungstic acid, phosphomolybdovanadic acid, phosphomolybdung tungstovanadic acid, phosphorus tungstovanadic acid, silicotungstic acid, or silicic acid. 3. The method for producing a polyacetal copolymer according to claim 1, wherein the polyacetal copolymer is at least one compound selected from molybdic acid, silicomolybdungstic acid, silicomolybdung tungstovanadic acid, and an acidic salt thereof. 4. The method for producing a polyacetal copolymer according to claim 1, wherein the non-volatile protonic acid catalyst (A) has an isopolyacid or an acidic salt thereof represented by the following general formula (2) or (3). xM ^I ₂ O ・ pM ^V ₂ O ₅・ yH ₂ O (2) xM ^I ₂ O ・ pM ^VI O ₃・ yH ₂ O (3) (However, M ^I is hydrogen or a part thereof is substituted by metal. M ^V may be V, Nb or Ta of the group ^V of the periodic table, M ^VI
Represents Cr, Mo, W or U in the Periodic Table VI, p represents an integer of 1 or more, x represents an integer of 1 or more, and y represents a number of 0 to 50. ] 5. An isopolyacid or an acid salt thereof, wherein the parapolytungstic acid, metatungstic acid, paramolybdic acid,
The method for producing a polyacetal copolymer according to claim 1 or 4, which is metamolybdic acid, paravanadate, metavanadate or an acid salt thereof. 6. A non-volatile proton acid catalyst (A) of 0.1 to 50 ppm (weight basis) and boron trifluoride or its coordination compound (B) of 3 to 50 ppm (boron trifluoride) based on all monomers. The method for producing a polyacetal copolymer according to any one of claims 1 to 5, wherein the polyacetal copolymer is used within a range of (weight basis). 7. The polyacetal copolymer according to claim 1, wherein the comonomer is at least one selected from 1,3-dioxolane, diethylene glycol formal, 1,4-butanediol formal, and ethylene oxide. Manufacturing method of coalescence. 8. A polymerization apparatus having at least two or more stages,
In the former polymerization unit, the copolymerization was carried out using the protonic acid polymerization catalyst (A) until the polymerization rate reached 60-90% (based on the total monomers supplied).
2. The polymerization according to claim 1, wherein the polymerization is continued by adding (B).
A method for producing a polyacetal copolymer according to any one of claims 1 to 7. 9. The process for producing a polyacetal copolymer according to claim 1, wherein a final polymerization yield (acquisition rate of the polymer based on all monomers supplied) is 95% or more. 10. After polymerization by the method according to any one of claims 1 to 9, a basic gas is brought into contact with the crude polymer as a catalyst deactivator or a solution containing a basic compound is produced. A method for producing a polyacetal copolymer, which comprises adding to a coalesced catalyst to deactivate a catalyst. 11. A basic gas as a catalyst deactivator,
The method for producing a polyacetal copolymer according to claim 10, which is ammonia and / or an amine compound having a boiling point of 150 ° C or lower. 12. A solution containing a basic compound as a catalyst deactivator, comprising ammonia, an amine compound, or an oxide or hydroxide of an alkali metal or alkaline earth metal,
The method for producing a polyacetal copolymer according to claim 10, which is an aqueous solution or an organic solvent solution containing at least one or two or more basic compounds selected from inorganic salts and organic acid salts. 13. The polyacetal copolymer according to any one of claims 1 to 12, wherein the crude polymer after polymerization is subjected to a catalyst deactivation treatment in a pulverized state containing at least 90% or more of a particle size of 3 mm or less. A method for producing a polymer. 14. The polyacetal copolymer according to any one of claims 10 to 13, wherein after the catalyst deactivator is added, the crude polymer is heated and melted without washing. Production method. 15. The method for producing a polyacetal copolymer according to claim 14, wherein the heat melting treatment is performed in the presence of a stabilizer. 16. The heat-melting treatment is carried out for 0.1 to 0.1% of the copolymer.
The method for producing a polyacetal copolymer according to any one of claims 14 to 15, which is carried out in the presence of water of up to 7% by weight.