JPS6212926B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel acetal polymer, and more particularly to an acetal polymer having a novel structure with unprecedented lubricity and a method for producing the same. Polyacetal is usually obtained by homopolymerizing formaldehyde or trioxane, or by copolymerizing formaldehyde or trioxane with a cyclic ether. Polyacetal obtained by homopolymerization has a hydroxyl group at the end and is unstable, and after converting the terminal hydroxyl group into a stable group by a method such as esterification, etherification, or urethanization, it cannot be used for practical use. served. On the other hand, polyacetal obtained by copolymerization has an unstable part consisting of repeating oxymethylene units at the end of the polymer, and the unstable part can be hydrated in the presence of a basic substance. After being disassembled, it is put into practical use. Japanese Patent Publication No. 35-9435 states that the molecular weight of a formaldehyde polymer is determined by the amounts of trace amounts of water, methanol, and formic acid present in the polymerization system. Further, US Pat. No. 3,017,389 describes that formaldehyde is polymerized in the coexistence of a chain transfer agent such as an alcohol, ester, acid anhydride, amide, or imide. Japanese Patent Publication No. 41-21638 discloses the addition of methylal, acetal, formic acid, etc. as a chain transfer agent during the copolymerization reaction of trioxane. Furthermore, JP-A-48-29843 describes copolymerization of trioxane in the presence of polyether. Further, Japanese Patent Publication No. 56-42611 discloses that the terminal hydroxyl group of a formaldehyde polymer is reacted with triorganohydroxysilane to stabilize the polymer. The present inventors have extensively studied molecular weight regulators to be used during polymerization and have found that a certain specific compound functions as a good molecular weight regulator. Furthermore, as a result, we have discovered a new acetal polymer that has extremely excellent lubricity that has not been found in conventional acetal polymers. That is, the present invention provides (1) a linear block copolymer of ABA or AB type (where A represents an acetal polymer unit and B represents a polysiloxane unit), which has a hydroxyl group at both ends;
It is blocked with an ether group, an ester group, or a urethane group, and has a number average molecular weight between 10,000 and 500,000, and the polysiloxane unit has the general formula (R ₁ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, n
= 2 to 2000), and the acetal polymer unit is a polyoxymethylene unit represented by repeating the general formula (-CH ₂ O)- or a unit represented by the general formula (-CH ₂ O)- oxymethylene unit
For 100 moles, the general formula (R ₀ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, m
= oxyalkylene unit represented by 2 to 6)
(2) A linear block of ABA or AB type (where A represents an acetal polymer unit and B represents a polysiloxane unit) A copolymer with hydroxyl groups at both ends,
It is blocked with an ether group, an ester group, or a urethane group, and has a number average molecular weight between 10,000 and 500,000, and the polysiloxane unit has the general formula (R ₁ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, n
= 2 to 2000), and the acetal polymer unit is a polyoxymethylene unit represented by repeating the general formula (-CH ₂ O)- or a unit represented by the general formula (-CH ₂ O)- oxymethylene unit
For 100 moles, the general formula (R ₀ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, m
= oxyalkylene unit represented by 2 to 6)
0.05 to 50 moles of random copolymer units, comprising homopolymerization of formaldehyde or trioxane, or formaldehyde, trioxane, or polyoxymethylene with the general formula (R ₀ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, m
= 2-6, n = 1-4, l = 1-2) using an anionic polymerization catalyst or a cationic polymerization catalyst. (R ₁ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, n
A novel method characterized in that it has a polysiloxane structure represented by 2 to 2000), the terminal is blocked with a hydroxyl group, an ether group, an ester group, or a urethane group, and is produced using a compound as a molecular weight regulator. The present invention relates to a method for producing an acetal polymer. The acetal polymer of the present invention has a friction coefficient of 0.16 to
With a value of 0.32, it is a thermally stable polymer with unprecedented lubricity. Excellent lubricity
It is based on the block structure of the acetal polymer, and at the same time the block structure of the acetal polymer is based on a molecular weight regulator having a molecular weight regulating function. Therefore, it goes without saying that the acetal polymer of the present invention has a desired molecular weight. Acetal polymers have been increasingly in demand as engineering resins in recent years, and improving the lubricity of acetal polymers has great industrial significance. Next, the acetal polymer of the present invention will be specifically explained. The acetal polymer of the present invention is a linear block copolymer of ABA or AB type (where A represents an acetal polymer unit and B represents a polysiloxane unit), and both ends thereof have a hydroxyl group, an ether group, or an ester group. , a urethane group, and the acetal polymer units include acetal homopolymer units and acetal copolymer units. An acetal homopolymer is a polymer consisting of repeating oxymethylene units [-CH ₂ O]-, and an acetal copolymer is a polymer consisting of oxyalkylene units in a chain consisting of oxymethylene units.

[Formula] A polymer having a structure in which (R ₀ : selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, m = 2 to 6) is randomly inserted. be. The insertion rate of oxyalkylene units in the acetal copolymer is 0.05 to 50 mol, more preferably 0.1 to 20 mol, per 100 mol of oxymethylene units. The structural formula of the acetal polymer of the present invention is as follows. ( _R2 : selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different. a, a', b, and b' are positive numbers representing a chain. This indicates that b oxyalkylene units are inserted into a oxymethylene units, and does not specify the distribution of oxyalkylene units in the polymer. ) Among the structural formulas shown above, when R ₂ is hydrogen, the acetal polymers represented by (1), (2), (5), and (6) have a hydroxyl group at the end and are unformed. It is stable. Among these, acetal homopolymer (1) and
(5) is put into practical use after converting the terminal hydroxy group into a stable group using a known method such as esterification, etherification, or urethanization. In addition, acetal copolymers (2) and (6) can be treated in the same manner as acetal homopolymers, or after removing unstable terminal parts by hydrolysis,
For practical use. The structure of the acetal polymer of the present invention is confirmed by the following method. That is, when an acetal polymer is hydrolyzed in an acidic aqueous solution, the portion consisting of repeating oxymethylene units becomes formaldehyde, and the portion of oxyalkylene units inserted into the acetal copolymer becomes alkylene glycol. becomes. Formaldehyde and alkylene glycol are analyzed and quantified using means such as gas chromatography and liquid chromatography. Also inserted into the linear polymer Also usually undergoes a hydrolysis reaction, resulting in a mixture of a cyclic siloxane oligomer and a linear polysiloxane. These compounds are also analyzed and quantified by gas chromatography, liquid chromatography, etc. The number average molecular weight of the acetal polymer of the present invention is
It is the same as that of ordinary high molecular weight polyacetal, but is generally between 10,000 and 500,000. The lower limit of the number average molecular weight is restricted by the physical properties of the acetal polymer, and the upper limit is restricted by the moldability of the acetal polymer. The number average molecular weight of the acetal polymer is determined by the following method. That is, when the number average molecular weight is 100,000 or less, osmotic pressure method,
Using the end group determination method, the number average molecular weight was
If it is 100,000 or more, the number average molecular weight is determined by combining the weight average molecular weight determined by the light scattering method and the elution curve determined by the gel permeation chromatography method (GPC method). Ru. Acetal polymer units of the present invention include acetal homopolymers and acetal copolymers. In acetal copolymers, the oxyalkylene units to be inserted into the polymer consisting primarily of repeating oxymethylene units have the general formula

[Formula] (R ₀ : is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, m=2 to 6). For example, oxymethylene unit [-(CH ₂ ) ₂ O]-, oxypropylene unit

[Formula] Oxytrimethylene unit [-(CH ₂ ) ₃ O]-, oxytetramethylene unit [-(CH ₂ ) ₄ O]-, oxybutylene unit

[Formula] Oxyhexamethylene unit [- (CH ₂ ) ₆ O] -, oxyphenylethylene unit

There is a [formula]. Among these oxyalkylene units, oxyethylene units and oxytetramethylene units are particularly preferred from the viewpoint of improving the physical properties of the acetal polymer. The polysiloxane unit forming the block segment of the acetal polymer of the present invention has the general formula It is expressed as Here R ₁ is hydrogen,
They are selected from alkyl groups and aryl groups, and may be the same or different. Specific examples of polysiloxane units include polymonomethylsiloxane, polydimethylsiloxane, polydiethylsiloxane, polydibutylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, and the like. Among these polysiloxane units, polydimethylsiloxane, polymethylphenylsiloxane, and polydiphenylsiloxane are particularly preferred because of their good stability and easy availability. The degree of polymerization (n) of polysiloxane is from 2 to 2000
It is necessary to be within the range of . In order to improve the lubricity of the polyacetal polymer, it is preferable that n be large. On the other hand, in order to maintain the mechanical properties of the acetal polymer, it is preferable that n be smaller. Considering both of these constraints, the most preferable range for n is between 3 and 500. The degree of polymerization (n) of polysiloxane can be determined using means such as liquid chromatography, viscosity measurement, and terminal group determination. Next, a method for producing the acetal polymer of the present invention will be described. The acetal polymer of the present invention has the general formula (R ₁ : selected from hydrogen, alkyl group, and aryl group, each of which may be the same or different. n
= 2 to 2000) as a molecular weight regulator, formaldehyde and trioxane are homopolymerized, or a compound selected from the group consisting of formaldehyde, trioxane, and polyoxymethylene is combined with a cyclic ether. It can be obtained by copolymerizing. The compound used as a molecular weight regulator in the present invention has the general formula It has a polysiloxane structure represented by: The degree of polymerization (n) of polysiloxane is 2
It is necessary to be in the range of 2000 and 3
It is preferable that it be in the range of 500 to 500. An example of the structural formula is shown below. (R ₂ ′, R ₃ ′: selected from hydrogen, alkyl group, and aryl group, each of which may be the same or different. R ₄ : alkyl group, aryl group) These molecular weight regulators are It is desirable that the product be purified by methods such as distillation, adsorption, and drying before being used. Moreover, these molecular weight regulators can be used alone, or two or more kinds can be mixed and subjected to polymerization. In the homopolymerization of the present invention, sufficiently purified formaldehyde or trioxane is used as a starting material. Anionic polymerization catalysts are mainly used for homopolymerization of formaldehyde, and cationic polymerization catalysts are used for homopolymerization of trioxane. In the copolymerization of the present invention, sufficiently purified formaldehyde, trioxane, and polyoxymethylene are used as starting materials. These starting materials are copolymerized with a cyclic ether using a cationic polymerization catalyst. The first group of cyclic ethers to be copolymerized with these starting materials include the general formula

There is an alkylene oxide represented by the formula: (R ₀ : hydrogen, alkyl group, aryl group, each of which may be the same or different; m=2 to 6). For example, ethylene oxide,
Propylene oxide, butylene oxide, epichlorohydrin, styrene oxide, oxetane,
Examples include 3,3-bis(chloromethyl)oxetane, tetrahydrofuran, and oxepane. Among these alkylene oxides, ethylene oxide is particularly preferred. The second group of cyclic ethers has the general formula

There is a cyclic formal represented by the formula. For example, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal,
1,5-pentanediol formal, 1,6-
There is hexanediol formal. Among these cyclic formals, ethylene glycol formal, diethylene glycol formal and 1,4-butanediol formal are particularly preferred. Cyclic ether per 100 parts by weight of starting materials
0.03 to 100 parts by weight, more preferably 0.1 to 50 parts by weight are used. The anionic polymerization catalyst and cationic polymerization catalyst used in the homopolymerization and copolymerization of the present invention are the following compounds. Typical groups of anionic polymerization catalysts include alkali metals such as sodium and potassium, alkali metal complexes such as sodium-naphthalene and potassium-anthracene, alkali metal hydrides such as sodium hydroxide, and alkaline earths such as calcium hydroxide. metal hydrides, alkali metal alkoxides such as sodium methoxide and potassium t-butoxide, alkali metal carboxylates such as sodium caproate and potassium stearate, alkaline earth metal carboxylates such as magnesium caproate and calcium stearate, Amines such as n-butylamine, diethylamine, trioctylamine, pyridine, ammonium stearate,
Quaternary ammonium salts such as tetrabutylammonium methoxide and dimethyldistearylammonium acetate; phosphonium salts such as tetramethylphosphonium propionate and trimethylbenzylphosphonium ethoxide; quaternary ammonium salts such as tributyltin chloride, diethyltin dilaurate, and dibutyltin dimethoxide Examples include valent organic tin compounds, alkyl metals such as n-butyllithium, and ethylmagnesium chloride. Cationic polymerization catalysts include tin tetrachloride, tin tetrabromide, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony pentafluoride, boron trifluoride, boron trifluoride diethyl etherate,
So-called Friedel-Crafts type compounds such as boron trifluoride coordination compounds such as boron trifluoride acetic anhydrate and boron trifluoride triethylamine complex compounds, perchloric acid, acetyl perchlorate, hydroxyacetic acid, trichloroacetic acid, Inorganic and organic acids such as p-toluenesulfonic acid, complex salt compounds such as triethyloxonium tetrafluoroborate, triphenylmethylhexafluoroantimonate, allyldiazonium hexafluorophosphate, allyldiazonium tetrafluoroborate, diethylzinc, triethyl aluminum,
Examples include alkali metals such as diethylaluminum chloride. These anionic polymerization catalysts and cationic polymerization catalysts are used in an amount of 0.0005 to 5 parts by weight based on 100 parts by weight of the starting material. Homopolymerization or copolymerization is carried out without solvent or in an organic medium. 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. The molecular weight regulator is used after being uniformly dissolved or dispersed in the reaction system. The concentration of the molecular weight regulator in the system can be easily determined by experiment, depending on the molecular weight requirements of the desired acetal polymer. The reaction temperature is set between -20 and 230℃,
In the case of no solvent, the temperature is more preferably between 20 and 210°C, and when an organic solvent is used, the temperature is more preferably between -10 and 120°C. There is no particular limit to the reaction time, but from 5 seconds
Set between 300 minutes. After a predetermined time has elapsed, a polymerization terminator is added to the reaction system to complete the homopolymerization or copolymerization. The resulting polymer is stabilized by removing unstable ends by hydrolysis or blocking unstable ends by a method such as esterification. The stabilized acetal polymer is put into practical use with the addition of a stabilizer and the like. The features of the acetal polymer of the present invention and its production method which have been described in detail above are listed below. (1) The acetal polymer has extremely excellent lubricity. (2) By using a specific compound, it is possible to impart excellent lubricity to the acetal polymer, and at the same time
Ability to arbitrarily control the molecular weight of the polymer. Measurement items in the following examples are as follows. Reduced viscosity: Value measured at 60°C in a p-chlorophenol/tetrachloroethane (1/1 weight ratio) solution at a polymer concentration of 0.5 g/dl. Reduced viscosity is an indicator of molecular weight. Friction coefficient: 0.25 parts of 2,2-methylene-bis(4-methyl-6-tert-butylphenol), polycaprolactam/polyhexamethyleneazibamide to 100 parts of polymer that has been terminally stabilized using acetic anhydride. / Added 0.75 parts of polyhexamethylene sebamide terpolymer, 50mmφ
Mixed and molded using an extruder, measured using a thrust type friction and wear tester, Compatible material: Metal (S45C) Load: 10Kg/cm ² , Linear speed: 12cm/sec The coefficient of friction is an index of lubricity. . Example 1 (1) Method for producing acetal polymer Formaldehyde gas with a purity of 99.9% was added at a rate of 100 parts (hereinafter, parts by weight) per hour, and 8.25 g/molecular weight regulator was added. (Polydimethylsiloxane dihydroxide,
As a polymerization catalyst (average degree of polymerization 20, hereinafter abbreviated as DMH-20), it was continuously fed for 3 hours into 500 parts of toluene containing 30 x 10 ^-4 mol./tetrabutylammonium laurate. Toluene containing DMH-20 and polymerization catalyst at the above concentrations also contains 500%
parts/hr for 3 hours, and the polymerization temperature was maintained at 65° C. during this period. The polymer was separated from toluene, then washed and dried to obtain 2.89 parts of polymer. (2) Confirmation of structure of acetal polymer 5 parts of the acetal polymer obtained in (1) were dispersed in 95 parts of 1N aqueous hydrochloric acid solution and heated at 92°C for 6 hours. Through this hydrolysis operation, the portion consisting of oxymethylene units returned to formaldehyde. Next, this solution was neutralized with a 0.5N aqueous caustic soda solution, and then analyzed using gas chromatography, and a large number of cyclic polydimethylsiloxanes were detected. When this solution was subjected to atomic absorption spectrometry to determine the Si content, 130 ppm of Si was detected relative to the polymer. Further, when this solution was dried to dryness under normal pressure and extracted with tetrahydrofuran, several types of linear polydimethylsiloxanes were detected in addition to the above-mentioned cyclic polydimethylsiloxane. On the other hand, 5 parts of the polymer obtained in (1) were dispersed in 100 parts of tetrahydrofuran, and after performing an extraction operation at 65°C for 24 hours, this solution was analyzed using gas chromatography and liquid chromatography. However, no polydimethylsiloxane derivatives were detected. From these two facts,
It is clear that DMH-20 is bonded to oxymethylene chains in the main chain of the polymer. Add 50 parts of the polymer obtained in (1) to 500 parts of acetic anhydride and sodium acetate.
0.1 part of the polymer was heated at 135°C for 3 hours to effect terminal acetylation, and 49 parts of the polymer was recovered. Next, the terminal acetyl group of this polymer was analyzed using infrared absorption spectroscopy, and it was found that 1.60×
10 ⁻³ moles of terminal acetyl groups were detected. This terminal acetyl group corresponds to the terminal hydroxy group of the polymer obtained in (1). In addition, the number average molecular weight of the polymer obtained in (1) (
n) was determined to be 41,000 by osmometry using a mixed solvent of p-chlorophenol/tetrachloroethane (1/1 weight ratio). From the above analysis results, the polymer obtained in (1) is a mixture of the following two types of polymers. Of the above two types of polymers, (A) is a polymer based on DMH-20 added as a molecular weight regulator, and (B) is a polymer based on a trace amount of water present in the polymerization system. Measurement of Physical Properties of Acetal Polymer The reduced viscosity of the acetal polymer obtained in (1) was 1.92, which was a desired value. After terminal stabilization using acetic anhydride,
When molded with the addition of a stabilizer, we were able to obtain a very strong molded product. Furthermore, the coefficient of friction of this molded article was 0.24, indicating excellent lubrication performance. Example 2 Method for producing acetal polymer 500 parts of sufficiently purified trioxane, 10 parts of ethylene oxide, and a molecular weight regulator were placed in a kneader having two Σ-type stirring blades. (Polydiphenylsiloxane dihydroxide, average degree of polymerization 50, hereinafter abbreviated as DPH-50) 130
and heated to 70°C. Next, boron trifluoride dibutyl etherate was added to this kneader.
0.25 part was added and stirred for 35 minutes. Immediately thereafter, 10 parts of tributylamine was added to stop the polymerization. The contents were taken out from the kneader and washed with acetone to obtain 598 parts of acetal polymer. (5) Confirmation of the structure of the acetal polymer By hydrolyzing the acetal polymer obtained in (4), the insertion rate of oxyethylene units in this polymer was determined to be 1.5 mol/100 mol oxymethylene units. The results were obtained. Further, Si in this polymer was 294 ppm. When quantified by acetylating the terminal hydroxyl group of the polymer obtained in (4), it was found to be 1.61×
A result of 10 ⁻³ mol/1 mol formaldehyde was obtained. Also, the number average molecular weight of this polymer is 47600
It was hot. From the above analytical values, the polymer obtained in (4) is
It is a mixture of the following two types of polymers. (d=0~1240, e=0~19 Structural formula〓〓CH ₂ O〓〓〓〓CH ₂ CH ₂ O〓〓H
indicates that 19 oxyethylene units are inserted into 1240 oxymethylene units, and does not specify the distribution of oxyethylene units in the polymer chain. ) Among the above two types of polymers, (C) is a polymer based on DPH-50 added as a molecular weight regulator, and (D) is a polymer based on a trace amount of water present in the polymerization system. (6) Measurement of physical properties of acetal polymer The measured physical properties of the acetal polymer obtained in (4) are as follows. Reduced viscosity 2.36 Coefficient of friction 0.23 This polymer has the desired molecular weight and also has excellent lubricity. Good lubricity is based on the polymer represented by (C). Example 3 (7) Production method of acetal polymer 150 parts of dehydrated and dried polyomethylene dimethoxide having a number average molecular weight of 1.5×10 ⁵ , 15.2 parts of 1,4-butanediol formal, molecular weight modifier An autoclave containing 15.3 parts of polydimethylsiloxane dimethoxide (average degree of polymerization 35, hereinafter abbreviated as DMM-35) and 500 parts of hexane was heated to 68°C by passing hot water through the jacket.
Next, 0.10 part of boron trifluoride dibutyl etherate was added to the autoclave and stirred for 25 minutes. After adding 10 parts of tributylamine to the autoclave, the contents were taken out, washed and dried to recover 166 parts of polymer. (8) Confirmation of structure of acetal polymer By hydrolyzing the polymer obtained in (7), the following results were obtained. The insertion rate of oxytetramethylene units is 2.93 moles/100 moles of oxymethylene units, the Si content in the polymer is 237 ppm, the hydroxyl group at the end of the polymer is below the detection limit, and the number average molecular weight is
It was 41400. From the above results, it was revealed that the polymer obtained in (7) was a mixture of the following two types of polymers. (f=0~1230, g=0~36, Structural formula = CH ₂ O = _{CH 2} ) ₄ O =
This shows that 36 oxytetramethylene units are inserted into 1230 oxymethylene units. ) Among the above two types of polymers, (E) is a polymer based on DMM-35 added as a molecular weight regulator, and (F) is a polymer based on the terminal methoxy group of the starting material polyoxymethylene. . (9) Measurement of physical properties of acetal polymer The polymer obtained in (7) had the desired molecular weight and a good coefficient of friction of 0.26. Good lubricity is
This is due to the polymer represented by (E). Comparative Example 1 (10) Method for producing polyacetal All the operations were performed in the same manner as in Example 1 except that 0.015 parts of water was added in place of DMH-20 among the reagents used in Example 1, and 287 parts of the polymer was Obtained. (11) Confirmation of the structure of polyacetal By acetylating the polymer obtained in (10),
A value of 14.7×10 ⁻⁴ mol of terminal acetyl group/1 mol formaldehyde was obtained. Therefore, the number average molecular weight of this polymer is 40,800, and it has a structure of 100% by weight of HO(CH ₂ O) ₁₃₆₁ H. (12) Measurement of physical properties of polyacetal The measured physical properties of the polymer obtained in (10) are as follows. The lubrication performance of the polymer obtained with reduced viscosity 2.08 and friction coefficient 0.37 (10) is poor. Examples 4 to 11 and Comparative Examples 2 to 3 The acetal polymers shown in Table 1 were produced using the starting materials, cyclic ethers, and molecular weight regulators shown in Table 1. Table 1 also shows the reduced viscosity and friction coefficient of the acetal polymer. In all Examples, the acetal polymer has good lubricating performance. On the other hand, in the comparative example, the lubrication performance was poor.

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Claims (1)

[Scope of Claims] 1. A linear block copolymer of ABA or AB type (where A represents an acetal polymer unit and B represents a polysiloxane unit), with both terminals having a hydroxyl group, an ether group, an ester group, is blocked by any of the urethane groups, has a number average molecular weight between 10,000 and 500,000, and the polysiloxane unit has the general formula (R ₁ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, n = 2
~2000), and the acetal polymer unit is a polyoxymethylene unit represented by repeating the general formula ( _-CH2O )- or a unit represented by the general formula ( _-CH2O )-.
)- for 100 moles of oxymethylene units represented by the general formula (R ₀ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, m = 2
0.05 to 50 oxyalkylene units represented by ~6)
A novel acetal polymer, which is a random copolymer unit with moles. 2 A linear block copolymer of ABA or AB type (where A represents an acetal polymer unit and B represents a polysiloxane unit), with either a hydroxyl group, ether group, ester group, or urethane group at both ends. blockade, the number average molecular weight is between 10,000 and 500,000, and the polysiloxane unit has the general formula (R ₁ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, n = 2
~2000), and the acetal polymer unit is a polyoxymethylene unit represented by repeating the general formula ( _-CH2O )- or a unit represented by the general formula ( _-CH2O )-.
)- for 100 moles of oxymethylene units represented by the general formula (R ₀ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, m = 2
0.05 to 50 oxyalkylene units represented by ~6)
In the method for producing a novel acetal polymer, which is a random copolymer unit with molar homopolymerization of formaldehyde or trioxane, or formaldehyde, trioxane,
Or polyoxymethylene and general formula (R ₀ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, m = 2
-6, n=1-4, l=1-2) using an anionic polymerization catalyst or a cationic polymerization catalyst, the general formula (R ₁ is selected from hydrogen, an alkyl group, and an aryl group, each of which may be the same or different, n = 2
~2000) has a polysiloxane structure represented by
1. A novel method for producing an acetal polymer, which is carried out using a compound whose terminal end is blocked with a hydroxyl group, an ether group, an ester group, or a urethane group as a molecular weight regulator.