JPS6212804B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing thermally stable polyacetal polymers. More specifically, polyoxymethylene having a number average molecular weight of 10,000 or more, an alkylene oxide, a cyclic formal,
The present invention relates to a method for producing a polyacetal polymer having excellent thermal stability and base stability by reacting it using a Lewis acid catalyst in the coexistence of a polyether. Japanese Patent Publication No. 43-26872 describes a method of reacting polyoxymethylene with 1,3-dioxolane, and Japanese Patent Publication No. 48-3711 describes a method of reacting polyoxymethylene with 1,3,6-trioxokene. A method is described. In these methods, side reactions frequently occur and the main chain of polyoxymethylene is cleaved, making it difficult to obtain stabilized polyoxymethylene with a constant molecular weight. Further, Japanese Patent Publication No. 52-9230 describes that polyoxymethylene is reacted with ethylene glycol or diethylene glycol. In this method, the reaction produces a large amount of water. The water produced acts as a chain transfer agent before being removed from the system.
Lowers the molecular weight of the polymer. In addition, this method also makes it difficult to control the reaction. Japanese Patent Publication No. 44-27667 discloses a method of reacting polyoxymethylene and a cyclic ether in an acidic reaction medium. This method also causes scission of the polyoxymethylene main chain, and a decrease in molecular weight is unavoidable. As a result of extensive studies on the stabilization reaction of polyoxymethylene, the present inventors found that when polyoxymethylene is reacted with an alkylene oxide and a cyclic formal in the coexistence of polyether, good physical properties and a desired molecular weight can be achieved. The present inventors have discovered that a stabilized polyacetal polymer having both of the following properties can be obtained in high yield, and have completed the present invention. That is, the first object of the present invention is to provide a method for producing a stabilized polyacetal polymer with excellent thermal stability and base stability by inserting an oxyalkylene bond into the polyoxymethylene main chain. . The second object of the present invention is to
It is an object of the present invention to provide a production method in which the molecular weight decreases little during the reaction, and a third object of the present invention is to provide a method for controlling the molecular weight. The present invention will be specifically explained below. The polyoxymethylene used in the present invention is a polymer having repeating oxymethylene units (-CH ₂ O-), and is a polymer in which both ends of the polymer are hydroxyl groups, or one or both ends of the polymer are This is a polymer blocked using a known method. Esterification methods, urethanization methods, etherification methods, and the like are known as methods for blocking polymer terminals. In addition, the molecular weight (number average molecular weight) of polyoxymethylene used as a starting material is at least
It is necessary that it is 10,000 or more, but from the practical performance of the stabilized polyacetal polymer, it is 30,000 or more.
It is more preferable that it is above. The upper limit of the molecular weight is mainly determined by the molecular weight of the desired stabilized polyacetal polymer and, if a molecular weight regulator is used, the amount of the molecular weight regulator used, but it is more preferably 500,000 or less. Examples of alkylene oxides that can be used in the present invention include ethylene oxide, propylene oxide, butylene oxide, trans-2.3-
Epoxybutane, cis-2・3-epoxybutane, isobutylene oxide, oxetane, 3・3
-bis(chloromethyl)oxetane, tetrahydrofuran, 2-methyltetrahydrofuran, oxepane, styrene oxide, p-chlorostyrene oxide, epichlorohydrin, cyclohexene oxide, and the like. Among these alkylene oxides, ethylene oxide, propylene oxide, butylene oxide, styrene oxide and cyclohexene oxide are particularly preferred. In addition, the first cyclic formal used in the present invention
The group is formal compounds of α・ω-alkylene glycol, such as ethylene glycol formal, propylene glycol formal, butylene glycol formal, 1,3-propanediol formal, 1,4-butanediol formal, 1,5-pentane Diol formal, 1,6-hexanediol formal,
Examples include 1,10-decanediol formal. The second group of cyclic formals is formal compounds of polyalkylene glycol, such as diethylene glycol formal, triethylene glycol formal, tetraethylene glycol formal, polyethylene glycol-200 formal, dipropylene glycol formal, polypropylene glycol-100 formal, Examples include polytetrabutylene glycol-200 formal. Among these cyclic formals, ethylene glycol formal, 1,4-butanediol formal, and diethylene glycol formal are particularly preferred from the viewpoint of reactivity and easy availability. In the present invention, a Lewis acid can be used as a catalyst. The first group of Lewis acids includes tin tetrachloride, tin tetrabromide, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, phosphorus pentafluoride, antimony trichloride, antimony pentafluoride, and trifluoride. Examples include Friedel-Crafts type compounds such as bromine, boron trifluoride, boron trifluoride diethyl etherate, boron trifluoride triethylamine acetate, and boron trifluoride polyethylene glycol coordination compounds. The second group of Lewis acids includes perchloric acid, acetyl perchlorate, t-butyl perchlorate, hydroxyacetic acid, trichloroacetic acid,
There are inorganic acids and organic acids such as trifluoromethanesulfonic acid and p-toluenesulfonic acid. The third group of Lewis acids includes complex salt compounds such as triphenylmethylhexafluoroantimonate, allyldiazonium hexachlorophosphate, and triethyloxonium tetrafluoroborate. A fourth group of Lewis acids includes organometallic compounds such as triethylaluminum, diethylaluminum chloride, aluminum isopropoxide, diethylzinc, and triethoxyboron. In addition to these four groups, molybdenum oxide acetylacetonate and the like can also be used as Lewis acids. Among these Lewis acids, Friedel-Crafts type compounds and complex salt compounds are more preferred in terms of activity, but Friedel-Crafts type compounds can also be formed by increasing the amount of inorganic acids, organic acids, and organometallic compounds. And it can bring about the same effect as a complex salt compound. In the present invention, as polyether, the general formula

[Formula] (R = selected from hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group, each of which may be the same or different. m = 2 to 6, n = 3 ~20000) can be used. Polyethers are usually obtained by ring-opening polymerization of the corresponding alkylene oxides. As ring-opening polymerization catalysts, cationic polymerization catalysts, anionic polymerization catalysts, coordination anionic polymerization catalysts, and the like are known. The first group of polyethers includes polyethylene oxide, which is a ring-opened polymer of ethylene oxide, and polyethylene oxide derivatives. For example, polyethylene glycol (average molecular weight
1500), polyethylene glycol diacetate (average molecular weight 10,000), polyethylene glycol dimethyl ether (average molecular weight 15,000), polyethylene glycol distearyl ether (average molecular weight
2150), polyethylene glycol p-nonylphenyl ether (average molecular weight 2350), glycerin ethylene oxide adduct (average molecular weight 5200), trimethylolpropane ethylene oxide adduct (average molecular weight 920), sorbitan monolaurate ethylene oxide adduct (average molecular weight 2350) ), pentaerythritol ethylene oxide adduct (average molecular weight 3400), polyethylene oxide (PEO, average molecular weight 50000), polyethylene oxide (PEO, average molecular weight 400000), etc. are included in this group. A second group of polyethers includes polypropylene oxide and polypropylene oxide derivatives, which are ring-opened polymers of propylene oxide. For example, polypropylene glycol (average molecular weight 7500), polypropylene glycol monolaurate (average molecular weight 15000), polypropylene glycol dimethyl ether (average molecular weight 6000),
Trimethylolpropane propylene oxide adduct (average molecular weight 7150), pentaerythritol propylene oxide adduct (average molecular weight 1150), polypropylene oxide (PPO, average molecular weight
100000) etc. are included in this group. A third group of polyethers includes polybutylene oxide and polybutylene oxide derivatives, which are ring-opened polymers of butylene oxide. For example, polybutylene glycol (average molecular weight
2000), polybutylene glycol dipropionate (average molecular weight 4300), polybutylene glycol dimethyl ether (average molecular weight 1000), etc. are included in this group.The fourth group of polyethers includes oxetane, ring-opening polymers of substituted oxetanes. For example, ring-opening polymers of trimethylene glycol (average molecular weight 450), trimethylene glycol dimethyl ether (average molecular weight 610), and 3,3-bis(chloromethyl)oxetane are The fifth group of polyethers includes tetrahydrofuran, polytetramethylene oxide, which is a ring-opening polymer of substituted tetrahydrofuran. For example, polytetramethylene glycol (average molecular weight 1250), polytetramethylene glycol dimethyl ether ( The sixth group of polyethers includes polyhexamethylene oxide, which is a ring-opening polymer of oxepane and substituted oxepane.For example, polyhexamethylene glycol (average molecular weight 850) is included in this group. , polyhexamethylene glycol dimethyl ether (average molecular weight 650), etc. are included in this group.The seventh group of polyethers includes styrene oxide, polystyrene oxide, which is a ring-opening polymer of substituted styrene oxide, and polystyrene oxide derivatives. For example, polystyrene glycol (average molecular weight 1850), polystyrene glycol dimethyl ether (average molecular weight 4500), poly p-chlorostyrene glycol (average molecular weight
2750) etc. are included in this group. In addition to the above seven groups, polyethers obtained by ring-opening polymerization of alkylene oxides other than the above-mentioned compounds are also effective. For example, a polymer obtained by ring-opening polymerization of epichlorohydrin, trans-
Polymers obtained by ring-opening polymerization of 2,3-epoxybutane can also be used in the present invention. Among these polyethers, polyethylene oxide, polyethylene oxide derivatives, polypropylene oxide, polypropylene oxide derivatives and polytetramethylene oxide are particularly preferred. In addition, the average degree of polymerization (n) of polyether is 3 to
It is necessary that the average degree of polymerization is between 20,000 and 10 or more, but the lower limit of the average degree of polymerization is more preferably 10 or more from the viewpoint of avoiding chain transfer reactions during reaction as much as possible, and the upper limit of the average degree of polymerization is determined by the ease of synthesis. From this point of view, it is more preferable that it is 10,000 or less. For example, glycerin ethylene oxide adduct When one molecule contains multiple polyether chains, the average degree of polymerization of each polyether chain (n ₁ , n ₂ , n ₃ ... It is necessary, and more preferably between 10 and 10,000. In addition to these polyethers, poly-2/6-
Dimethyl-p-phenylene oxide and the like can also be used as polyethers. In the present invention, the molecular weight of the stabilized polyacetal polymer can also be arbitrarily adjusted using a molecular weight regulator. Molecular weight regulators that can be used in the present invention include acetal compounds, orthoformates, alcohols, carboxylic acids, carboxylic anhydrides, and water. The first group of acetal compounds are:
There are formal compounds and hemiformal compounds represented by ROCH ₂ OR and HOCH ₂ OR. Here R
is a C ₁ to C ₈ straight chain or branched alkyl group. Specifically, methylal, diethoxymethane,
Examples include di-iso-propoxymethane, di-n-butoxymethane, butoxyhydroxymethane, and the like. The second group of acetal compounds are:
There is a polyacetal compound represented by RO(CH ₂ O)nR. Here, R is a _C1 - _C8 straight chain or branched alkyl group, and n is an integer of 2-20. Specifically, dioxymethylene dimethoxide,
Examples include tetraoxymethylene dioctoxide, decaoxymethylene diisopropoxide, dioxymethylene diethoxide, and the like. These compounds are often difficult to isolate as single substances and are usually used as a mixture. The degree of polymerization (n) of these compounds can be determined by nuclear magnetic resonance spectroscopy,
It can be determined using means such as gas chromatography and liquid chromatography. The third group of acetal compounds is

There is an acetal compound represented by the formula: Here, R is a C ₁ to C ₈ linear or branched alkyl group. Specific examples include dimethyl acetal, diethyl acetal, di-iso-propyl acetal, di-t-butyl acetal, dihexyl acetal, and dioctyl acetal. The orthoformic acid ester is a compound represented by HC(OR) ₃ , where R is a group selected from a C ₁ to _{C 4} linear alkyl group and a phenyl group. Specifically, methyl orthoformate, ethyl orthoformate,
Examples include diethylpropyl orthoformate, propyl orthoformate, and phenyl orthoformate. Alcohol is a compound represented by ROH, and R is a group selected from _C1 to _C20 linear or branched alkyl groups and aryl groups. Specifically, there are aliphatic alcohols such as methanol, ethanol, n-propanol, iso-butanol, lauryl alcohol and stearyl alcohol, and aromatic alcohols such as benzyl alcohol and 2-phenylethanol. Carboxylic acid is a compound represented by RCOOH, where R is a group selected from hydrogen, a C ₁ to _{C 20} linear or branched alkyl group, and an aryl group. Specifically, there are aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, lauric acid, and stearic acid, and aromatic carboxylic acids such as benzoic acid and iso-phthalic acid. Carboxylic acid anhydride is

【formula】 【formula】

【formula】

It is a compound represented by the formula: Here, R ₁ is a C ₁ to C ₂₀ linear alkyl group, R ₂ is hydrogen or a C ₁ to C ₂₀ linear alkyl group, and R ₃ is hydrogen or a C ₁ to _{C 3} linear or branched group. It is an alkyl group with a shape. Specifically, aliphatic carboxylic anhydrides such as acetic anhydride, propionic anhydride, stearic anhydride, succinic anhydride, dodecenylsuccinic anhydride, and maleic anhydride; aromatic carboxylic anhydrides such as phthalic anhydride and 4-methylphthalic anhydride; There are acid anhydrides. Among these molecular weight modifiers, from the viewpoint of thermal stability and base stability of the polymer, formal compounds represented by ROCH ₂ OR, polyacetal compounds represented by RO(CH ₂ O) nR, and

An acetal compound represented by the formula is preferable, and methylal and diethyl acetal are particularly preferable from the viewpoint of ease of purification and availability. polyoxymethylene and alkylene oxide,
The reaction with the cyclic formal is carried out without a solvent or in an organic medium. The reaction without a solvent is usually carried out by adding a Lewis acid to a mixture of polyoxymethylene, an alkylene oxide, and a cyclic formal, with the polyoxymethylene as a raw material in a solid powder state or in a molten state. In addition, the reaction in an organic medium is
This is usually carried out by adding a Lewis acid to an organic medium containing raw materials polyoxymethylene, alkylene oxide, and cyclic formal. Organic media that can be used in the present invention include aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, and cyclopentane, benzene, toluene,
Examples include aromatic hydrocarbons such as xylene, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, ethylene chloride, and trichloroethylene, and halogenated aromatic hydrocarbons such as chlorobenzene and o-dichlorobenzene. These organic media may be used alone or in combination of two or more. When using a molecular weight regulator, the molecular weight regulator is uniformly dissolved or dispersed in the reaction system. The concentration of the molecular weight regulator in the system is
Depending on the requirements, the molecular weight of the desired stabilized polyacetal polymer can be easily determined by experiment. The amount of alkylene oxide and cyclic formal is 0.01 to 200 parts by weight per 100 parts by weight of raw material polyoxymethylene.
It is used in an amount of 0.1 to 100 parts by weight, preferably 0.1 to 100 parts by weight. Polyether is raw material polyoxymethylene 100
It is used in an amount of 0.001 to 50 parts by weight, more preferably 0.01 to 5 parts by weight. The Lewis acid is used in an amount of 0.0005 to 2.0 parts by weight per 100 parts by weight of raw material polyoxymethylene in the case of no solvent, and in an amount of 1×10 ^-7 to 1× in the case of using an organic medium.
Used at a concentration of 10 ^-1 mol/- organic medium. The reaction temperature is usually set between -20 and 230°C, but preferably between 20 and 210°C in the case of no solvent, and more preferably between 0 and 120°C when using an organic medium. . There is no particular limit to the reaction time, but from 5 seconds
Set between 300 minutes. In the case of no solvent, a basic substance such as sodium hydroxide, ammonia, amine, or quaternary ammonium salt is added to the system after a predetermined period of time has passed, and the reaction is completed. It is also possible to add stabilizers, etc. to the stabilized polyacetal polymer and put it into practical use.
Furthermore, after heating the stabilized polyacetal polymer with water, alcohol, etc., a stabilizer etc. can be added to the polymer for practical use. When an organic medium is used, the polymer is separated from the organic medium after a predetermined period of time, and a basic substance such as sodium hydroxide, ammonia, amine, or quaternary ammonium salt is added to complete the reaction. It is also possible to add a stabilizer to the stabilized polyacetal polymer as it is for practical use. Alternatively, after heating the stabilized polyacetal polymer with water, alcohol, etc., a stabilizer etc. can be added to it for practical use. By using the method of the present invention described in detail above, it has become possible to obtain a good stabilized polyacetal polymer. The features of the present invention are listed as follows:
It is as follows. (1) It is possible to produce a stabilized polyacetal polymer with excellent thermal stability and base stability. (2) Almost no decrease in molecular weight occurs during the stabilization reaction. (3) By using a molecular weight regulator, the molecular weight of the stabilized polyacetal polymer can be adjusted as desired. (4) By using a specific molecular weight regulator, it is possible to simultaneously control the molecular weight and improve thermal stability and base stability. Measured values in the following examples are based on the following measurement method. Molecular weight (number average molecular weight): Based on terminal group determination method. That is, the terminal alkoxy group was quantified using the modified Zeisel method. The terminal hydroxyl group (-OH) was converted to an acetyl group (-OCOCH ₃ ) using acetic anhydride, and then quantified using infrared absorption spectroscopy. The terminal carboxyl group (-OCOR, R: hydrogen, alkyl group) was also quantified using infrared absorption spectroscopy. Reduced viscosity: 0.5gr./in p-chlorophenol-tetrachlorethylene (1:1 weight ratio) solution
Polymer concentration of dl, measured at 60℃. Base stability yield: at 5% polymer concentration in benzyl alcohol containing 1% tributylamine
Polymer recovery rate when heat treated at 150℃ for 60 minutes. It is a measure of base stability. Rv222: The amount of polymer remaining after heating at 222°C under vacuum for 50 minutes. It is a measure of thermal stability. The present invention will be explained below with reference to some examples.
The present invention is not limited to these examples. Example 1 50 gr. of polyoxymethylene dihydroxide sufficiently dried under reduced pressure with a number average molecular weight of 59500 and a reduced viscosity of 2.95, 0.3 gr. of polyethylene glycol (average molecular weight 6000) as a polyether, 4 mg of methylal as a molecular weight regulator, propylene oxide
3.8 gr. and 500 ml of anhydrous toluene were charged to the flask. After preparation, the contents of the flask were heated to 50°C.
The temperature was raised to . Add 10 mg of anhydrous tin tetrachloride to this solution.
was added to start the reaction. Contents of flask 50
After maintaining the temperature at °C for 60 minutes, 1 ml of tributylamine was added to stop the reaction. After separating the polymer, it was washed 5 times with methanol and vacuum dried at 60°C for 5 hours to obtain 50g of polymer. This polymer had a desired molecular weight, with a molecular weight of 34,200 and a reduced viscosity of 1.76. Furthermore, the base-stabilized yield of this polymer was 93%, and the Rv of the base-stabilized polymer was 98.6%, indicating that it had good thermal stability and base stability. Example 2 A flask was charged with 200 gr. of polyoxymethylene diacetate with a molecular weight of 65500 and a reduced viscosity of 3.26, 1.4 gr. of polytetramethylene glycol (average molecular weight 4500), 14 gr. of styrene oxide, and 1000 ml of cyclohexane, and the contents of the flask were heated to 75°C. The temperature was raised to . The reaction was then started by adding 12 mg of boron trifluoride dibutyl ether to the flask. After maintaining the contents of the flask at 75 °C for 35 minutes,
The reaction was stopped by adding 10 ml of 1NKOH ethanol solution. Separately, washing and drying were performed to obtain 196 gr. of polymer. The molecular weight of this polymer is 59400, and the reduced viscosity is
2.92, the base-stabilized yield was 93%, the Rv of the polymer after base-stabilization was 98.0%, and a stabilized polyacetal polymer with good properties was obtained. Examples 3 to 13 Polyoxymethylene with a molecular weight of 52,700 and a reduced viscosity of 2.45 (53% of all terminals are capped with acetyl groups and 47% with methoxy groups) 200 gr., alkylene oxide or cyclic formal, polyether shown in Table 1 When a molecular weight regulator was used, the molecular weight regulator and 1000 ml of toluene were charged into a flask.
The reaction was initiated by adding the Lewis acids listed in Table 1 to the flask. After maintaining the contents of the flask at 60 °C for 45 minutes,
The reaction was stopped by adding 15 ml of a 10 ml ammonia aqueous solution. The sample was then separated, washed and dried, and the results shown in Table 1 were obtained. In all Examples, stabilized polyacetal polymers having the desired molecular weight and excellent thermal stability and base stability were obtained. Comparative Example 1 All operations were performed in the same manner as in Example 1, except that the use of polyethylene glycol used in Example 1 was stopped.
The obtained results are also shown in Table 1. A decrease in the molecular weight of the polymer was observed during the reaction. Comparative Example 2 All operations were performed in the same manner as in Example 4, except that the use of polytetramethylene glycol used in Example 4 was discontinued, and the obtained results are also shown in Table 1. In the reaction, the molecular weight was significantly reduced and only a low viscosity polymer was recovered. Example 14 Polyoxymethylene diacetate with a molecular weight of 40,100 and a reduced viscosity of 1.91 with both ends capped with acetic anhydride.
350 gr., polyethylene glycol monolauryl ether (average molecular weight 1950) 1.0 gr., and propylene oxide 15 gr. were placed in an autoclave. The contents were then stirred at high speed and heated to 100°C. 5 ml of methylene chloride containing 12 mg of acetyl perchlorate synthesized from acetyl chloride and silver perchlorate was added to the autoclave using a pressure injection device to initiate the reaction. After 12 minutes, 6 ml of dioctylamine was added using a metering pump to stop the reaction.
After washing the polymer with acetone, it was dried to recover 340 gr. of polymer. The molecular weight of this polymer is 37600,
The reduced viscosity was 1.80, and the decrease in molecular weight was surprisingly small. Cyanoguanidine is added to 100 parts of this polymer.
0.5 parts, 2,2-methylene-bis(4-methyl-
When 0.15 part of 6-t-butylphenol was added to the mixture and subjected to molding, a molded product with strong physical properties was obtained. Example 15 Polyoxymethylene with molecular weight 65000 and reduced viscosity 3.36 (42% of all terminals are capped with methoxy groups, 58% hydroxyl groups) 1500gr., polyethylene glycol dimethyl ether (average molecular weight 1000) 1.2gr., diethylene glycol formal 35gr. After mixing 75 mg of diethyl acetal inside a sufficiently dried hopper, it was extruded using a 30 mmφ extruder with L/D=35 equipped with a vent port. The time required for extrusion was 28 minutes, and the temperature of the molten resin at the die exit was 190°C. 120 mg of boron trifluoride was added to 100 ml of toluene to prepare a catalyst solution. This catalyst solution was forcibly added through the vent port using a metering pump at a rate of 2 ml per minute over the 28 minutes required for extrusion. The average residence time of the resin from the vent port to the die exit is 30
It was hot in seconds. 1.1% of the molten resin coming out of the die
lead into KOH aqueous solution and total as strands
1470 gr. of polymer was recovered. This polymer had a desired molecular weight, with a molecular weight of 34,400 and a ring viscosity of 1.78.

【table】

【table】

Claims (1)

[Scope of Claims] 1. Polyoxymethylene having a number average molecular weight of 10,000 or more and the general formula (R is selected from hydrogen, an alkyl group, a substituted alkyl group, an aryl group, and a substituted aryl group, each of which may be the same or different, m = 2 to 6) and the alkylene oxide represented by the general formula (R' is selected from hydrogen, an alkyl group, a substituted alkyl group, an aryl group, and a substituted aryl group, each of which may be the same or different, m' = 2 to 6,
When reacting a compound selected from the group consisting of cyclic formals represented by n' = 1 to 4, l' = 1 to 2) using a Lewis acid as a catalyst, the general formula (R″ is selected from hydrogen, an alkyl group, a substituted alkyl group, an aryl group, and a substituted aryl group, and each may be the same or different, m″=2 to 6,
A method for producing a stabilized polyacetal polymer characterized by coexisting a polyether represented by n″=3 to 20000).