JPS5915332B2 - polyacetal polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel polyacetal polymer, and particularly to a polyacetal polymer having a novel terminal structure that has unprecedented thermal stability, lubricity, and anti-static properties. It is.

Oxymethylene units obtained by polymerizing high-purity formaldehyde using a polymerization catalyst such as an amine or an onium salt (
-OCH.

Polyacetal, which is a highly polymerized polymer consisting of repeats of -), has its terminal hydroxyl group blocked by a method such as esterification, etherification, or urethanization.
Widely used as a strong engineering plastic. o In the polymerization of formaldehyde, water, methanol, formic acid, etc. are used as molecular weight regulators of the polymer, as disclosed in, for example, Japanese Patent Publication No. 35-9435.

As a result of extensive studies on molecular weight regulators, the present inventors found that a certain specific compound not only functions as a good molecular weight regulator, but also plays the role of end-capping, and as a result, it has been found that a certain compound functions as a good molecular weight regulator and also plays the role of terminal blocking. We have discovered a new polyacetal polymer that has extremely excellent thermal stability, lubricity, and antistatic properties that have never been seen before. That is, the present invention provides a linear polyacetal polymer consisting of repeating oxymethylene units (-0CH2-), in which one end has the general formula F
(R1: 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.

R2: The main component is a polymer capped with an alkylene oxide adduct to an alcohol represented by an alkyl group, substituted alkyl group, aryl group, substituted aryl group, m = 2 to 6, n = 1 to 1,000). This invention relates to a high molecular weight polyacetal polymer characterized by: The high molecular weight polyacetal polymer of the present invention has an Rv of 96 to 100.
%, friction coefficient 0.14-0.30, surface electrical resistance 1×1
It is a thermally stable polymer having a value of 011 to 1 x 1016 Ω, and has unprecedentedly excellent lubricity and antistatic properties. Such excellent performance is based on the terminal structure of the polyacetal polymer, and at the same time, the terminal structure of the polyacetal polymer is based on a molecular weight regulator having an extremely excellent molecular weight regulating function. Therefore, it goes without saying that the polyacetal polymer of the present invention has a desired molecular weight. Demand for polyacetal as an engineering resin has been increasing in recent years.
Improvements in the lubricating performance and antistatic performance of polyacetal have great industrial significance.

Next, the polyacetal polymer of the present invention will be specifically explained.

The polyacetal polymer referred to in the present invention is a linear polymer consisting of repeating oxymethylene units, and one end of the polymer is blocked with.

An example of the structural formula is as follows. (1: average degree of polymerization, R3: hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group) The polyacetal polymer represented by the structural formula (1) has a hydroxyl group at the terminal and is not It is stable.

The hydroxyl group at the end of the polymer is unstable and is usually converted into a stable group using known methods such as esterification, etherification, and urethanization. The polymer represented by the structural formula (2) has both ends blocked and is stable, and can be put to practical use as is. The structure of the polyacetal polymer of the present invention is confirmed by the following method. That is, when a polyacetal polymer is hydrolyzed in an acidic aqueous solution, the portion consisting of repeating oxymethylene units returns to formaldehyde (CH2O). Another terminal J! V1 - Sulfuric acid, analyzed and quantified by gas chromatography, liquid chromatography, etc.

The number average molecular weight of the portion consisting of repeating oxymethylene units excluding the terminal groups of the polyacetal polymer of the present invention is the same as that of ordinary high molecular weight polyacetals, but generally ranges from 10,000 to 500,000. Adopted.

The lower limit of the number average molecular weight is restricted by the physical properties of the polyacetal polymer, and the E 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 10
If the number average molecular weight is 0,000 or less, use the osmotic pressure method or end group determination method, and if the number average molecular weight is 100,000 or more, use the weight average molecular weight determined by the light scattering method and the gel permission method. The number average molecular weight is determined by combining it with the elution curve determined by chromatography (G.P.C. method). The alkylene oxide adduct to the alcohol forming one end of the polyacetal polymer of the present invention has the general formula R2OL
(size) It is a compound having a structure represented by MOIfn, and is usually an alcohol represented by the general formula R2OH (R2: alkyl group, substituted alkyl group, aryl group, substituted aryl group), and a general formula (R1: hydrogen, alkyl group). group, substituted alkyl group, aryl group, substituted aryl group,
They may be the same or different.

It is a compound to which an alkylene oxide represented by m=2 to 6) is added. Examples of the alcohol include methyl alcohol, ethyl alcohol, Sec-butyl alcohol, hexyl alcohol, cyclohexyl alcohol, octyl alcohol, decyl alcohol, lauryl alcohol, cetyl alcohol, stearyl alcohol,
Examples include eicosanol, ceryl alcohol, myricyl alcohol, oleyl alcohol, 3-ethyl-6-undecanol, phenol, p-butylphenol, p-octylphenol, p-nonylphenol, benzyl alcohol, and p-butylbenzyl alcohol.

Among these alcohols, from the viewpoint of improving the lubricating performance of the polyacetal polymer, long-chain aliphatic alcohols having 8 or more carbon atoms and p-alkyl substituted phenols are preferable, and from the viewpoint of easy availability, lauryl alcohol, stearyl Particularly preferred are alcohols, eicosanol, p-octylphenol and p-nonylphenol.

Examples of alkylene oxide include ethylene oxide, propylene oxide, butylene oxide,
Fluhydrin, styrene oxide, oxetane, 3,3
-bis(chloromethyl)oxetane, tetrahydrofuran, 2-methyltetrahydrofuran, oxepane, etc. Among these alkylene oxides, ethylene oxide is particularly preferred from the viewpoint of antistatic performance, and ethylene oxide and propylene oxide are particularly preferred from the viewpoint of easy availability. These alkylene oxides can be used alone or in combination of two or more.

Alternatively, for example, propylene oxide is first added to the alcohol, and then ethylene oxide is added thereto,
Furthermore, propylene oxide can also be added. Number of moles of alkylene oxide added per mole of alcohol (
n) must be in the range of 1 to 1,000.

In order to improve the lubricating performance and antistatic performance of the polyacetal polymer, it is preferable that n be large, while from the viewpoint of ease of production and purification, it is preferable that n be small. Based on both of these constraints, the most preferable range of n is 2 to
It is between 250. Further, the number of moles (n) of alkylene oxide added per mole of alcohol can be easily determined by quantifying the hydroxyl group at one end of the produced adduct.

Next, a method for producing the polyacetal polymer of the present invention will be described.

The polyacetal polymer of the present invention has the general formula Tl? ，
1:? ．． (R1:
It 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.

R2: alkyl group, substituted alkyl group, aryl group, substituted aryl group, R3: hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group, m=2-6, n=1-
It can be obtained by polymerizing formaldehyde in the coexistence of a compound selected from alkylene oxide adducts to alcohols represented by 1,000) and ester compounds of the same adducts. As alkylene oxide adducts to alcohols, the compounds already described in detail can be used.

In addition to alkylene oxide adducts to alcohols, general formulas R3COOH, R3qO5R3 (R3: hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group)
Using carboxylic acid and carboxylic acid anhydride represented by
An ester compound obtained by esterifying the terminal hydroxyl group of an alkylene oxide adduct to an alcohol can also be used in the present invention. Examples of carboxylic acids and carboxylic acid anhydrides include formic acid, acetic acid, propionic acid, caproic acid, 2-ethylhexanoic acid, lauric acid, stearic acid, atarylic acid, methyl methacrylic acid, benzoic acid, mandelic acid, and acetic anhydride. , propionic anhydride, caproic anhydride, benzoic anhydride, and the like. Among these carboxylic acids and carboxylic acid anhydrides, acetic acid and acetic anhydride are particularly preferred from the viewpoint of ease of esterification reaction. It is desirable that alkylene oxide adducts to alcohols and ester compounds of the same adducts be purified by methods such as distillation, adsorption, drying, etc. prior to polymerization.

Further, these compounds can be used alone, or two or more kinds can be mixed and subjected to polymerization. In the present invention, for formaldehyde polymerization, catalysts generally known as anionic polymerization catalysts, coordination anionic polymerization catalysts, and cationic polymerization catalysts can be used.

Representative groups of anionic polymerization catalysts and coordination anionic polymerization catalysts include alkali metals such as sodium and potassium, alkali metal complex compounds such as sodium-naphthalene and potassium-anthracene, alkali metal hydrides such as sodium hydride, hydrogen Alkaline earth metal hydrides such as calcium chloride, alkali metal alkoxides such as sodium methoxide and potassium t-butoxide, alkali metal carboxylates such as sodium caproate and potassium stearate, and carboxylic acids such as magnesium caproate and calcium stearate. Alkaline earth metal salts, amines such as n-butylamine, diethylamine, trioctylamine, pyridine, quaternary ammonium salts such as ammonium stearate, tetrabutylammonium methoxide, dimethyldistearylammonium acetate, tetramethylphosphonium propionate , phosphonium salts such as trimethylbenzylphosphonium ethoxide, tetravalent organotin compounds such as tributyltin chloride, diethyltin dilaurate, dibutyltin dimethoxide, and alkyl metals such as n-butyllithium and ethylmagnesium chloride.

Examples of cationic polymerization catalysts include tin tetrachloride, tin tetrabromide, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony pentafluoride, boron trifluoride, boron trifluoride diethyl etherate, and trifluoride. So-called Friedel compounds such as boron trifluoride coordination compounds such as boron acetate anhydrate and boron trifluoride triethylamine complex compounds
Kraft-type compounds, inorganic and organic acids such as perchloric acid, acetyl perchlorate, hydroxyacetic acid, trichloroacetic acid, p-toluenesulfonic acid, triethyloxonium tetrafluoroborate, triphenylmethylhexafluoroantimonate, allyldiazonium hexafluoro Examples include complex salt compounds such as phosphate and allyldiazonium tetrafluoroborate, and alkyl metals such as diethylzinc, triethylaluminum, and diethylaluminum chloride.

Further, in the present invention, polymerization is usually carried out in an organic medium.

Examples of 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. Examples 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, a molecular weight regulator selected from an alkylene oxide adduct to alcohol, and an ester compound of the same adduct. The legal method is a method in which an organic medium containing a molecular weight regulator is cooled, formaldehyde gas is absorbed into this 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 1×10−
A concentration of 2 to 1.times.10@-6 mol/l of organic medium is used.

The polymerization temperature is -50 to 118°C in the case of the blow polymerization method.
In the case of solution polymerization, it is often set between -70 and 5'C.

There is no particular restriction on the polymerization time, but it is between 5 seconds and 30 seconds.
Set between 0 minutes.

After the completed polymerization is separated from the organic medium,
The terminal unstable portion is blocked using, for example, acetic anhydride, and then a stabilizer and the like are added, and the product is put into practical use.

The features of the polyacetal polymer of the present invention and its production method which have been described in detail above are listed below.

(1) The polyacetal polymer has extremely excellent thermal stability, lubricity, and antistatic properties.

(2) By using a specific compound, excellent performance can be imparted to polyacetal polymers, and at the same time, the molecular weight of the polymers can be controlled arbitrarily.

Measurement items in the following examples are as follows.

Reduced viscosity: Polymer concentration 0.5 gr/in p-chlorophenol-tetrachlorethylene (1:1 weight ratio) solution
Measured value at 60°C with D2.

R222: This is the amount remaining after heating a polymer that has been terminally stabilized using acetic anhydride at 222°C for 60 minutes under vacuum, and is an index of the thermal stability of the polymer.

Friction coefficient: 2,2-methylene-bis(4-methyl-
Add 0.25 parts of 6-tert-butylphenol) and 0.75 parts of polycaprolactam/polyhexamethylene adipamide/polyhexamethylene sebacamide terpolymer, mix using a 50 mmφ extruder, and then mix using a thrust type extruder. Measured using a friction and wear tester, mating material: metal (S45C), load: 10KV, linear speed: 12-/? C friction coefficient is an index of lubricity.

Surface electrical resistance: The surface electrical resistance of the same polymer at 20℃,
50%R. H. Measured below, it is an indicator of antistatic properties.

Example 1 (1) Production of polyacetal polymer Thoroughly dehydrated and dried paraformaldehyde was heated at 150°C.
By thermally decomposing the product and passing it through a cooling trap several times, formaldehyde gas with a purity of 99.9% was obtained.

110 parts per hour (the following parts indicate parts by weight).

) formaldehyde gas at 1.0×10-4 m01
/l of tetrabutylammonium acetate, as molecular weight regulator, 5.

0×10-3m01/l (7) Cl8H37O(Cl-
L! It was introduced into 500 parts of toluene containing C[-120)40H (ethylene oxide adduct to stearyl alcohol, average number of moles of ethylene oxide added: 40, hereinafter abbreviated as S-40).

At the same time as formaldehyde gas supply, 1.0×10-
4m01/l of tetrabutylammonium acetate,
5.0 x 10-3 m01/l<S7) Toluene containing S-40 was continuously supplied at a rate of 500 parts per hour for 3 hours. Formaldehyde gas was also continuously supplied at a rate of 110 parts per hour for 3 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. The polymer was thoroughly washed with acetone and then dried under vacuum at 60°C to obtain 289 parts of a white polymer. 2) Confirmation of structure of polyacetal polymer 5 parts of the polyacetal polymer obtained in (1) were dispersed in 95 parts of 1N hydrochloric acid aqueous solution and heated at 90° C. for 5 hours.

By this heating operation, the part consisting of repeating oxymethylene units is completely hydrolyzed and formaldehyde (
CH2O). On the other hand, under these conditions, alkylene oxide adducts to alcohols do not undergo hydrolysis. Next, this solution was neutralized with 0.5N aqueous sodium hydroxide solution, the liquid was evaporated at normal pressure, and then 50% of tetrahydrofuran was added.
The extraction operation was carried out by adding a portion of the solution. When the extract was quantified using liquid chromatography, it was determined that Cl8Fl37O (CH
2Cl-]20) 7.5 x 10-4 mol of 40H was detected per 1 mol of formaldehyde. 50 parts of the polyacetal polymer obtained in (1) was heated at 139° C. for 3 hours with 500 parts of acetic anhydride and 0.1 part of sodium acetate, and 49 parts of the polymer were recovered. Next, this polymer was subjected to infrared absorption spectrum analysis, and the terminal acetyl group (-0CZH3
), the terminal acetyl group was detected in an amount of 8.5 x 104 moles per mole of formaldehyde.
The terminal groups quantified as terminal acetyl groups in this analysis are:
The terminal human xyl group (-0H) of the polymer obtained in (1)
). Calculation of number average molecular weight is based on Mn
= 6 tentative total terminal groups (mol/mol formaldehyde) and obtained a value of Mn = 37,500. From the above results, the structure and composition of the polyacetal polymer obtained in (1) are as follows. Among the above two types of polymers, (A)
(B) is a polymer based on S-40 added as a molecular weight regulator, and (B) is a polymer based on a trace amount of water present in the polymerization system.

(3) Measurement of physical properties of polyacetal polymer The reduced viscosity of the polyacetal polymer obtained in (1) is 2.
05, which was the desired value.

Moreover, Rv had excellent thermal stability of 99%. When a stabilizer was then added to the terminal-stabilized polymer and molded, a very strong molded product was obtained.
The molded product had a friction coefficient of 0.16 and a surface electrical resistance of 4×10 11 Ω, and had excellent lubrication performance and antistatic performance. Example 2 99.9% pure formaldehyde gas per hour
1 x 10-4 m01/l dibutyltin dilaurate in the proportion of 10 parts, 16.0 x 10-3 as molecular weight regulator
m01/l(7)QHl7O(CH2CNf))20α
continuously for 3 hours in 500 parts of cyclohexane containing ℃r (an ester compound obtained by acetylating an ethylene oxide adduct to octyl alcohol, the average number of added moles of engineered ethylene oxide is 20, hereinafter abbreviated as 0-20). supplied.

Cyclohexane containing dibutyltin dilaurate O-20 at the above concentration was also continuously fed at a rate of 500 parts/Hr for 3 hours, and the polymerization temperature was maintained at 45° C. during this period. The polymer was separated from citalohexane, washed and dried to obtain 288 parts of polymer. Infrared absorption spectrum analysis of this polymer was conducted, and it was found that the terminal acetyl group was 9.5 x 10-4.
The value of rn01/tomi01CH20 was obtained.

Furthermore, by acid hydrolysis of this polymer, 9.5
×1I4m01/Tsuma01CH20C8Hl,O-(C
H, CH, O)20H was quantified. After this polymer was acetylated using acetic anhydride, the terminal acetyl group was measured and found to be 1.10 x 10-3 m0Vm01C[-120. From the above results, the following number average molecular weight 29,30
It was confirmed that 0 polymer was produced. This polymer had the desired molecular weight and reduced viscosity of 1.63, as expected.

Also, Rv98%, friction coefficient 0.22, surface electrical resistance 8×
1111 and all were good. Example 3 Of the reagents used in Example 1, boron trifluoride dibutyl etherate of 1 x 10-3 m0V1 was used in place of tetrabutylammonium acetate, and the polymerization temperature was set at -8°C.
All other operations were carried out in the same manner as in Example 1 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 was 1.58, and the terminal group was C,8H3TO (C
In addition to H2{H2O+40, -0H, the presence of -0CH3 (analyzed using modified Zeisel method) and -09H (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 0.17, and a surface electrical resistance of 5 x 1011 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, the first
All operations were performed in the same manner as in Example 1 except that the molecular weight regulator shown in the table was used. The results 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, 1.5×10−3rr101Δ was used instead of tetrabutylammonium acetate.
The procedure was repeated in the same manner as in Example 1, except that the polymerization was carried out at 0°C using tin tetrachloride shown in Table 1 in place of S-40, and the molecular weight regulator shown in Table 1 was used. The results are shown in Table 1.

It is clear that a polymer with good physical properties was obtained. Comparative Example 1 Among the reagents used in Example 1, all the reagents were the same as in Example 1, except that hexanol was used as a molecular weight regulator instead of S-40.
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 otatyl propionate was used as a molecular weight regulator in place of S-40, and the results are shown in Table 1. Indicated.

Claims (1)

[Claims] 1 One end of a linear polymer consisting of repeating oxymethylene units has a general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (R_1: hydrogen, alkyl group, substituted alkyl group, aryl group, selected from substituted aryl groups, each of which may be the same or different. R_2: alkyl group, substituted alkyl group, aryl group, substituted aryl group, m = 2 to 6, n = 1,000); capped with an alkylene oxide adduct to the represented alcohol, with a number average molecular weight excluding end groups of 10,000 to 5
00,000 polyacetal polymer. 2. The polymer according to claim 1, wherein the alcohol is a long-chain aliphatic alcohol having 8 or more carbon atoms. 3. The polymer according to claim 2, wherein the alcohol is lauryl alcohol, stearyl alcohol, or eicosanol. 4. The polymer according to claim 1, wherein the alcohol is a p-alkyl substituted phenol. 5. The polymer according to claim 4, wherein the alcohol is p-octylphenol or p-nonylphenol. 6. The polymer according to claim 1, wherein the alkylene oxide is ethylene oxide. 7. The polymer according to claim 1, wherein the alkylene oxide is propylene oxide. 8. The polymer according to any one of claims 1 to 7, wherein the number of moles (n) of alkylene oxide added per mole of alcohol is in the range of 2 to 250.