JPS6213970B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel polyacetal polymer having a desired molecular weight and excellent thermal stability, lubricity, and antistatic properties, and a method for producing the same. More specifically, it relates to a new polyacetal polymer with excellent thermal stability, lubricity, and antistatic properties obtained by polymerizing formaldehyde using an alkylene oxide adduct to carboxylic acid as a molecular weight regulator. be. 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 presence of a chain transfer agent such as an alcohol, ester, acid anhydride, amide, imide, etc. and an initiator. Among the chain transfer agents found in these disclosures, compounds having so-called active hydrogen serve as good chain transfer agents, but have the disadvantage that the thermal stability of the resulting polymers is not necessarily good. In addition, compounds such as esters, acid anhydrides, amides, imides, etc.
The disadvantage is that the molecular weight is not sufficiently controlled and it is difficult to control the molecular weight. Furthermore, the lubricity and antistatic properties of polymers produced using these chain transfer agents are poor, and they cannot be used in applications that particularly require lubrication and antistatic properties. As a result of extensive studies on methods for controlling the molecular weight of polyacetal polymers, the present inventors have found that alkylene oxide adducts to carboxylic acids function as good molecular weight control agents, and the resulting new polymers exhibit excellent thermal stability and
It was discovered that the lubricity and antistatic properties were also good, leading to the completion of the present invention. That is, the present invention provides an oxymethylene unit (-
One end of the linear polymer consisting of repeating OCH ₂ ―) has the general formula

[Formula] (R ₁ : hydrogen, alkyl group, substituted alkyl group, aryl group,
They are selected from substituted aryl groups and may be the same or different. R ₂ : selected from 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 or 4, n = 2 to 250), which is capped with an alkylene oxide adduct to a carboxylic acid, and has a number average molecular weight of 10,000 to 10,000, excluding the terminal group.
General formula using a new polyacetal polymer between 500,000 and any of anionic polymerization catalyst, coordination anionic polymerization catalyst, and cationic polymerization catalyst

[Formula] (R ₁ : selected from hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group, each of which may be the same or different. R ₂ : alkyl group, substituted alkyl group,
They are selected from aryl groups and substituted aryl groups and may be the same or different. An object of the present invention is to provide a method for producing a novel polyacetal polymer, which is characterized in that formaldehyde is polymerized in the presence of an alkylene oxide adduct to a carboxylic acid represented by m=2 or 4, n=2 to 250. The novel polyacetal polymer obtained by the method of the present invention has excellent thermal stability, lubricity, and antistatic properties, and is suitable for lubrication and antistatic applications. Furthermore, in the method of the present invention, the molecular weight of the polyacetal polymer can be easily controlled, and a polyacetal polymer having a desired molecular weight can be obtained. The present invention will be specifically explained below. The new polyacetal polymer referred to in the present invention is
It is a linear polymer consisting of repeating oxymethylene units (-OCH ₂ -), and one end of the polymer is

It is a polymer blocked by the formula. When the alkylene oxide adduct to carboxylic acid functions as a molecular weight regulator, one end of the resulting linear polymer is

[Formula] The other end becomes a hydroxyl group (-OH). The hydroxyl group at the end of the polymer is unstable;
Usually, it can be converted into a stable group using known methods such as esterification, etherification, and urethanization. at the end

The polymer of the present invention having the group [Formula] is confirmed by the following method. That is, an IN HCl solution containing a polyacetal polymer at a concentration of 5% by weight is heated at 90° C. for at least 3 hours to completely hydrolyze the polyacetal polymer. Next, after neutralizing the aqueous solution, the liquid is evaporated to dryness, and then a solvent such as tetrahydrofuran is added to extract soluble substances. The extract is analyzed by gas chromatography, liquid chromatography, or the like. According to this method, the end of the polymer

[Formula] The group is

[Formula] and

Detected and quantified as [Formula]. The number average molecular weight of the portion consisting of repeating oxymethylene units (-OCH ₂ -) excluding the terminal group of the polyacetal polymer of the present invention is from 10,000 to 10,000.
It must be between 500,000 and 500,000. The lower limit of the number average molecular weight is restricted by the physical properties of the polyacetal polymer, and the upper limit is restricted by the moldability of the polyacetal polymer. The number average molecular weight of a polyacetal polymer is determined by the following method. That is, the number average molecular weight is
If it is less than 100,000, it is determined using an osmotic pressure method or an end group determination method. Also, the number average molecular weight is 100000
In the above cases, combine the weight average molecular weight determined by the light scattering method and the elution curve determined by the gel permeation chromatography method (GPC method).
The number average molecular weight is determined. Next, the molecular weight regulator that can be used in the present invention will be explained. In the present invention, a carboxylic acid represented by the general formula R ₂ COOH is used as a starting material for synthesizing an alkylene oxide adduct. Here, R ₂ is selected from an alkyl group, a substituted alkyl group, an aryl group, and a substituted aryl group. For example, acetic acid, propionic acid, caproic acid, 2-ethylhexanoic acid, lauric acid, palmitic acid, stearic acid, behenic acid, oleic acid, linoleic acid, ricinoleic acid, phenylacetic acid, cinnamic acid, benzoic acid, p-octylbenzoic acid. , α-naphthalic acid, etc. Among these carboxylic acids, from the viewpoint of improving the lubrication performance of the polyacetal polymer, long-chain aliphatic carboxylic acids having 8 or more carbon atoms are preferred, and from the viewpoint of easy availability, lauric acid, stearic acid, and oleic acid are preferred. and ricinoleic acid are particularly preferred. In the present invention, the alkylene oxide that can be added to the above alcohol has the general formula

A compound represented by the formula can be used. Here, R ₁ 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.
Moreover, m=2-6. For example, ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, styrene oxide, oxetane, 3,3-bis(chloromethyl)oxetane,
Examples include tetrahydrofuran, 2-methyltetrahydrofuran, and oxepane. Among these medium alkylene oxides, from the viewpoint of antistatic performance,
Ethylene oxide is particularly preferred, and from the viewpoint of easy availability, ethylene oxide and propylene oxide are particularly preferred. These alkylene oxides can be used alone or in combination of two or more. Alternatively, for example, propylene oxide can be added to the carboxylic acid first, then ethylene oxide can be added thereto, and then propylene oxide can be added thereto. The number of moles (n) of alkylene oxide added per mole of carboxylic acid must be in the range of 1 to 1000. Lubricating performance of polyacetal polymer,
In order to improve the antistatic performance, it is preferable that n be large, while from the viewpoint of ease of production and purification, it is preferable that n be small. Considering both of these constraints, the most preferable range for n is between 2 and 250. Synthesis of alkylene oxide adducts to carboxylic acids is usually carried out using anionic or cationic catalysts. Alternatively, it can be synthesized by esterifying one end of polyalkylene glycol with a carboxylic acid or carboxylic acid anhydride. In this case, it is preferable to proceed with the esterification reaction under conditions that can suppress the production of polyalkylene glycol diester compounds as much as possible. Also carboxylic acid 1
The number of moles (n) of alkylene oxide added per mole can be easily determined by quantifying the hydroxyl group at one end of the adduct produced. Prior to polymerization, the alkylene oxide adduct to carboxylic acid is preferably purified by methods such as distillation, adsorption, and drying. Further, these compounds can be used alone, or two or more kinds can be mixed and subjected to polymerization. In the present invention, catalysts generally known as anionic polymerization catalysts, coordination anionic polymerization catalysts, and cationic polymerization catalysts can be used for formaldehyde polymerization. Typical groups of anionic polymerization catalysts and coordination 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 hydride, hydrogen Alkaline earth metal hydrides such as calcium oxide, alkali metal alkoxides such as sodium methoxide and potassium t-butoxide, alkali metal carboxylates such as sodium caproate and potassium stearate, magnesium caproate,
Carboxylic acid alkaline earth metal salts such as calcium stearate, amines such as n-butylamine, diethylamine, trioctylamine, pyridine,
Quaternary ammonium salts such as ammonium stearate, tetrabutylammonium methoxide, dimethyl distearyl ammonium acetate, phosphonium salts such as tetramethylphosnium propionate, trimethylbenzylphosphonium ethoxide, tributyltin chloride, diethyltin dilaurate, dibutyl Examples include tetravalent organic tin compounds such as tin dimethoxide, 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 alkyl metals such as diethylaluminum chloride. Further, in the present invention, polymerization is usually carried out in an organic medium. Organic media that can be used in the present invention include aliphatic hydrocarbons such as n-hexane, n-heptane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, and halogens such as methylene chloride, chloroform, and trichloroethylene. These include halogenated aliphatic hydrocarbons and halogenated aromatic hydrocarbons such as chlorobenzene. These organic media may be used alone or in combination of two or more. The formaldehyde used in the present invention must be substantially anhydrous and must be purified using a known method such as a cold trap method or a solvent washing method. For producing the polyacetal polymer of the present invention, conventionally known methods such as blow polymerization and solution polymerization can be used. The blow polymerization method is a method in which formaldehyde gas is directly blown into an organic medium containing a polymerization catalyst and an alkylene oxide adduct to carboxylic acid as a molecular weight regulator, and the solution polymerization method is a method in which formaldehyde gas is directly blown into an organic medium containing a polymerization catalyst and an alkylene oxide adduct to a carboxylic acid as a molecular weight regulator. In this method, an organic medium is cooled, formaldehyde gas is absorbed into the solution, and then a polymerization catalyst is added to initiate polymerization. The molecular weight regulator is used after being uniformly dissolved or dispersed in an organic medium. The concentration of the molecular weight modifier in the organic medium can be easily determined experimentally depending on the molecular weight requirements of the desired polyacetal polymer. The polymerization catalyst is used in a concentration of 1.times.10.sup. ^-2 to 1.times.10.sup. ^-6 mol/l of organic medium. The polymerization temperature is often set between -50 to 118°C in the case of the blow polymerization method and between -70 to 50°C in the case of the solution polymerization method. In addition, there is no particular restriction on the polymerization time, but
It is set between 5 seconds and 300 minutes. After the polymerization has been completed, the polymer is separated from the organic medium, the terminal unstable portions are blocked using, for example, acetic anhydride, and then a stabilizer and the like are added, and the polymer is put into practical use. By using the production method of the present invention described in detail above, it has become possible to obtain a novel polyacetal polymer having both a desired molecular weight and excellent performance. Here, the features of the present invention are listed as follows. (1) It is possible to arbitrarily control the molecular weight of the polyacetal polymer. (2) It is possible to control the molecular weight and at the same time impart excellent thermal stability, lubricating properties, and antistatic properties to polyacetal polymers. The measurement items in the following implementation are as follows. Reduced viscosity: Value measured at 60°C in a p-chlorophenol-tetrachloroethylene (1:1 weight ratio) solution at a polymer concentration of 0.5 gr./dl. Rv222: This is the amount of heat remaining when a polymer that has been terminally stabilized with acetic anhydride is heated at 222°C under vacuum for 60 minutes, and is an indicator of the thermal stability of the polymer. Friction coefficient: 2,2-methylene-bis(4-methyl-6-tert-butylphenol) is added to 100 parts of a polymer that has been terminally stabilized using acetic anhydride.
0.25 parts of polycaprolactam/polyhexamethylene adipamide/polyhexamethylene sebamide terpolymer 0.75 parts were added, mixed and molded using a 50 mmφ extruder, and measured using a thrust type friction and wear tester. Mating material: Metal (S45℃) Load: 10Kg/cm ² , Linear speed: 12cm/sec The coefficient of friction is an index of lubricity. Surface electrical resistance: The surface electrical resistance of the same polymer as 20
Measured at ℃ and 50%RH, and is an indicator of antistatic properties. Example 1 (1) Production of new polyacetal polymer Thoroughly dehydrated and dried paraformaldehyde was
By thermally decomposing it at 150°C and passing it through a cooling trap several times, formaldehyde gas with a purity of 99.9% was obtained. 100 parts (hereinafter, parts are by weight) of formaldehyde gas per hour to 1×10 ^-4 mol.
/ dibutyltin dilaurate and 3.5×10 ^-3 mol./ as a molecular weight regulator.

[Formula] (ethylene oxide adduct to stearic acid, average number of added moles of ethylene oxide 20, hereinafter abbreviated as ST-20) was introduced into 500 parts of toluene. At the same time as formaldehyde gas was supplied, 1.0×10 ^-4 mol./dibutyltin dilaurate, 3.5×10 ^-3 mol./
Toluene containing ST-20 was continuously supplied for 5 hours at a rate of 500 parts per hour. Formaldehyde gas was also continuously supplied at a rate of 100 parts per hour for 5 hours, during which time the polymerization temperature was maintained at 60°C. Toluene containing the polymer was continuously extracted in proportion to the amount supplied, and the polymer was separated by filtration. After thoroughly washing the polymer with acetone, it was vacuum dried at 60°C to obtain 475 parts of a white polymer. (2) Confirmation of structure of new polyacetal polymer 5 parts of the polyacetal polymer obtained in (1) were dispersed in 95 parts of 1N aqueous hydrochloric acid solution and heated at 90°C for 5 hours. By this heating operation, the portion consisting of repeating oxymethylene units was completely hydrolyzed and returned to formaldehyde (CH ₂ O). Next, this solution was neutralized with 0.5N caustic soda aqueous solution, the liquid was evaporated at normal pressure, and then tetrahydrofuran 50
of the solution was added, and the extraction operation was performed. When the extract is quantified using liquid chromatography, HO
(CH ₂ CH ₂ O) ₂₀ H was detected in an amount of 7.1×10 ⁻⁴ mol with respect to 1 mol of formaldehyde, and C ₁₇ H ₃₅ COOH was detected in an amount of 7.1×10 ⁻⁴ mol with respect to ₁ mol of formaldehyde. Further, when the polymer obtained in (1) was subjected to infrared absorption spectrum analysis, 7.1×10 ^-4 moles of carbonyl groups were detected per mole of formaldehyde. 50 parts of the polymer obtained in (1) was heated with 500 parts of acetic anhydride and 0.1 part of sodium acetate at 139°C for 3 hours to effect terminal acetylation, and then 49 parts of the polymer were recovered. Next, the carbonyl group of this polymer was analyzed and found to be 15.0 per mole of formaldehyde.
×10 ^-4 mol was detected. That is, the number of carbonyl groups increased by 7.9 moles due to acetylation. This increased carbonyl group corresponds to the terminal hydroxyl group (-OH) of the polymer obtained in (1). From the above analysis, the total terminal group of the polymer obtained in (1) is 15.0 × 10 ^-4 mol, and the number average molecular weight is:
It is determined to be 40,000 according to n=60/total end groups (mol/mol of formaldehyde). The structure and composition of the polymer obtained in (1) are as follows. Of the above two types of polymers, (A) is a polymer based on ST-20 added as a molecular weight regulator, and (B) is a polymer based on water that was present in a small amount in the polymerization system. (3) Measurement of physical properties of polyacetal polymer The reduced viscosity of the polyacetal polymer obtained in (1) is
It was 2.02, which was the desired value. Also, R _v is 98
% and had excellent thermal stability. When a stabilizer was then added to the terminal-stabilized polymer and molded, a very strong molded product was obtained. Furthermore, this molded article had a friction coefficient of 0.19 and a surface electrical resistance of 6×10 ¹¹ Ω, and had excellent lubrication performance and antistatic performance. Example 2 Formaldehyde gas with a purity of 99.9% was mixed at a rate of 100 parts per hour with 1×10 ^-4 mol./tetrabutylammonium acetate and 4.0×10 ^-3 mol./as a molecular weight regulator.

[Formula] (ethylene oxide adduct to 2-ethylhexanoic acid, average number of added moles of ethylene oxide 40, hereinafter abbreviated as OC-40)
was continuously fed for 3 hours into 500 parts of cyclohexane containing . Cyclohexane containing tetrabutylammonium acetate, OC-40 at the above concentration was also continuously fed at a rate of 500 parts/hr for 3 hours, during which time the polymerization temperature was maintained at 45°C. The polymer was separated from cyclohexane, washed and dried to obtain 286 parts of polymer. Infrared absorption spectrum analysis of this polymer was performed, and the terminal carbonyl group was 7.5×10 ^-4 mol./mol.CH ₂ O.
obtained the value of In addition, by acid hydrolysis of this polymer, 7.5×10 ^-4 mol./mol.CH ₂ O, HO
(CH ₂ CH ₂ O) ₄₀ H and C ₇ H ₁₅ COOH were detected. After acetylating this polymer with acetic anhydride, the number of unterminated carbonyl groups was measured to be 1.60×10 ^-3 mol./
It was mol.CH ₂ O. From the above results, it was confirmed that the following polymer with a number average molecular weight of 37,500 was produced. This polymer had the desired molecular weight and reduced viscosity of 1.83, which was as expected. Also Rv98
%, friction coefficient of 0.20, and surface electrical resistance of 4×10 ¹¹ Ω, all of which were good. Example 3 Of the reagents used in Example 2, 1×10 ^-3 mol./in place of tetrabutylammonium acetate.
using boron trifluoride dibutyl etherate,
All operations were conducted in the same manner as in Example 2, except that the polymerization temperature was -8°C, to obtain 265 parts of a polymer. The molecular weight and composition of this polymer were analyzed and the following results were obtained. The reduced viscosity of the polymer obtained using a cationic polymerization catalyst is 1.58, and the

[Formula] - In addition to OH - OCH ₃ (analyzed using the modified Zeisel method) and

The presence of [Formula] (analyzed using infrared absorption spectroscopy) was observed. This polymer has excellent lubricating and antistatic properties with an Rv of 98%, a coefficient of friction of 0.20, and a surface electrical resistance of 5×10 ¹¹ Ω.It is a polyacetal polymer that has good performance even when using a cationic polymerization catalyst. It was possible to obtain it. Examples 4 to 10 Among the reagents used in Example 1, all operations were performed in the same manner as in Example 1 except that the molecular weight regulator shown in Table 1 was used in place of ST-20, and the results obtained were are shown in Table 1. In all Examples, polyacetal polymers having good lubrication performance and antistatic performance were obtained. Examples 11 and 12 Among the reagents used in Example 1, 1.5×10 ^-3 mol./tin tetrachloride was used in place of dibutyltin dilaurate, and the reagents shown in Table 1 were used in place of ST-20. All operations were carried out in the same manner as in Example 1, except that a molecular weight regulator was used and the polymerization was carried out at 0°C, and the results obtained are shown in Table 1. It is clear that a polymer with good physical properties was obtained. Comparative Example 1 All of the reagents used in Example 1 were operated in the same manner as in Example 1, except that hexanol was used as a molecular weight regulator instead of ST-20, and the results are shown in Table 1. Although it is possible to control the molecular weight by using hexanol, the lubricity and antistatic properties were poor. Comparative Example 2 Among the reagents used in Example 1, all operations were performed in the same manner as in Example 1, except that octyl propionate was used as a molecular weight regulator instead of ST-20, and the results are shown in Table 1. Indicated. In the case of n-octylpropionate, the molecular weight control of the polymer was incomplete, and at the same time, the lubricity and antistatic properties were also poor.

【table】

【table】

Claims (1)

[Claims] 1 One end of a linear polymer consisting of repeating oxymethylene units (-OCH ₂ -) has the general formula [Formula] (R ₁ : hydrogen, alkyl group, substituted alkyl group, aryl group, substituted selected from aryl groups, which may be the same or different. R ₂ : alkyl group, substituted alkyl group,
They are selected from aryl groups and substituted aryl groups and may be the same or different. A novel polyacetal polymer capped with an alkylene oxide adduct to a carboxylic acid represented by m=2 or 4, n=2 to 250) and having a number average molecular weight excluding terminal groups of between 10,000 and 500,000. 2 anionic polymerization catalyst, coordination anionic polymerization catalyst,
and a cationic polymerization catalyst using the general formula [Formula] (R ₁ : hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group, each of which may be the same or different). _Good.R2 : alkyl group, substituted alkyl group,
They are selected from aryl groups and substituted aryl groups and may be the same or different. 1. A method for producing a novel polyacetal polymer, which comprises polymerizing formaldehyde in the presence of an alkylene oxide adduct to a carboxylic acid (m=2 or 4, n=2-250).