JPH059363A - Slidable oxymethylene polymer composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having excellent initial lubricating characteristics and long-term characteristics by adding a specific olefin polymer to a specific oxymethylene polymer. CONSTITUTION:(B) An olefin compound composed of an olefin unit shown by formula III [R3 and R3' are H, (substituted) alkyl, (substituted) aryl or ether; k is 10-500] is added to (A) an oxymethylene polymer wherein one end of a linear polymer consisting of repetition of oxymethylene unit is blocked with a residue of an adduct of an alcohol with an alkylene oxide and/or a residue of an adduct of a carboxylic acid with an alkylene oxide shown by formula I and/or formula II [R1 and R1' are H, (substituted) alkyl or (substituted) aryl; R2 is (substituted) alkyl or (substituted) aryl; m is 2-6; n is 1-1,000] and the number-average molecular weight except the end groups is 10,000-500,000 to give the objective composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slidable oxymethylene polymer composition having excellent initial lubricating properties and long-term lubricating properties.

[0002]

2. Description of the Related Art Polyoxymethylene is widely used as an engineering resin in gears, bearings, other mechanical parts and electric parts because of its excellent mechanical strength, fatigue resistance and electric characteristics. In addition, polyoxymethylene is quite excellent in self-lubricating property, and there are many applications in which its characteristics are utilized.

However, in order to improve the functions and diversification of polyoxymethylene, the self-lubricating property inherent in polyoxymethylene and the addition of various lubricants to polyoxymethylene are used to remove polyoxymethylene compositions. The kinematics are not always sufficient, and the slidability needs to be further improved. Conventionally, as a method for improving the slidability of polyoxymethylene, for example, (1) adding a solid lubricant such as molybdenum disulfide, (2) adding powder or fiber such as polyethylene or polytetrafluoroethylene. how to,
(3) A method of adding a liquid such as petroleum-based lubricating oil or synthetic lubricating oil, or a solid lubricant is well known.

Above all, adding an olefinic lubricant such as polyethylene or liquid paraffin is a very useful method from the viewpoint of improving the slidability of polyoxymethylene. However, these olefin-based lubricants have a drawback that they have essentially low compatibility with polyoxymethylene as well as other lubricants, and excellent sliding properties cannot be maintained for a long period of time.

That is, when a molded product obtained from the composition is used as a sliding part, it exhibits excellent slidability while the lubricant bleeding out on the surface of the molded product is present at the sliding interface. However, if it scatters from the sliding interface, the slidability of the molded product is greatly reduced, and the slidability excellent in the long-term lubrication characteristics referred to in the present invention cannot be obtained. This is due to the low compatibility of the lubricant with polyoxymethylene.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a slidable oxymethylene polymer composition having excellent initial lubricating properties and long-term lubricating properties. More specifically, the object of the present invention is to obtain a molded article obtained from the composition of the present invention in a sliding part, which has a low coefficient of friction immediately after use (initial lubrication property), and has a long-term low friction coefficient. An object of the present invention is to provide a high sliding material that maintains a friction coefficient and has an extremely small amount of wear (long-term lubrication characteristics).

[0007]

As a result of intensive studies, the present inventors have found that a composition obtained by adding a specific olefin compound to a specific oxymethylene polymer has slidability, particularly initial lubrication. It was found that it has excellent characteristics and long-term lubrication characteristics. That is, in the present invention, one end of a linear polymer composed of repeating (1) (A) oxymethylene units has the general formula

[0008]

[Chemical 3]

(R ₁ and R ₁ ′ are selected from hydrogen, an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group, and they may be the same or different, and are bonded to different carbon atoms. R ₁ and R ₁ ′ may be the same or different, and R ₂ is selected from an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group.
= 2 to 6, n = 1 to 1,000), an end group capped with a compound selected from the group consisting of an alkylene oxide adduct residue to an alcohol and an alkylene oxide adduct residue to a carboxylic acid. Oxymethylene polymer (B) general formula having a number average molecular weight excluding 10,000 to 500,000

[0010]

[Chemical 4]

(R ₃ and R ₃ ′ are selected from hydrogen, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group and an ether group, and they may be the same or different. K = 10 To 500), and a slidable oxymethylene polymer composition (2) polyoxymethylene comprising an olefin compound composed of at least one olefin unit, and the above (1). Is a slidable polyoxymethylene composition.

In the following description of the present invention, all alkyl groups or aryl groups also include substituted alkyl groups or substituted aryl groups, respectively. The oxymethylene polymer composition of the present invention will be specifically described. The oxymethylene polymer referred to in the present invention is a linear polymer composed of repeating oxymethylene units, and one end of the polymer is

[0013]

[Chemical 5]

It is a polymer represented by An example of the structural formula is as follows.

[0015]

[Chemical 6]

The oxymethylene polymer represented by the above structural formula has a hydroxyl group at the terminal and is unstable, and is usually a stable group using a known method such as esterification, etherification and urethanization. Is converted to. The number average molecular weight of the portion formed by repeating the oxymethylene unit excluding the terminal group of the oxymethylene polymer is the same as that of a normal high molecular weight polyoxymethylene, but is about 10,000.
A range of 0 to 500,000 is adopted. The lower limit of the number average molecular weight is restricted by the physical properties of the oxymethylene polymer, and the upper limit is restricted by the moldability of the oxymethylene polymer.

In the present invention, the residue of the alkylene oxide adduct to the alcohol or carboxylic acid forming one end of the oxymethylene polymer is represented by the general formula

[0018]

[Chemical 7]

It is represented by A compound having a structure, and these residues are usually represented by the general formula R ₂ OH (R ₂ : alkyl group, aryl group) or

[0020]

[Chemical 8]

Alcohols or carboxylic acids represented by (R ₂ : alkyl group, aryl group) have the general formula

[0022]

[Chemical 9]

(R ₁ , R ₁ ′: selected from hydrogen, an alkyl group and an aryl group, which may be the same or different, and R ₁ and R ₁ ′ bonded to different carbon atoms may also be used. They may be the same or different, m = 2 to 6).
It is a residue consisting of a compound to which an alkylene oxide represented by 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, eicosanol, ceryl alcohol, myricyl alcohol, oleyl alcohol, triterpene. Alcohol, 3-ethyl-6-undecanol, phenol, p
-Butylphenol, p-octylphenol, p-nonylphenol, benzyl alcohol, p-butylbenzyl alcohol and the like.

Among these alcohols, from the viewpoint of improving the slidability of the oxymethylene polymer, long-chain aliphatic alcohols having 8 or more carbon atoms and p-alkyl-substituted phenols are preferable, and lauryl alcohol and stearyl are more preferable. Alcohol, eicosanol, p-octylphenol and p-nonylphenol are particularly preferred. Examples of the carboxylic acid include 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,
Examples include p-octylbenzoic acid and α-naphthalic acid. Among these carboxylic acids, from the viewpoint of improving the slidability of the oxymethylene polymer, a long-chain aliphatic carboxylic acid having 8 or more carbon atoms is preferable, and further, lauric acid, stearic acid, oleic acid and ricinol. Acids are particularly preferred.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, styrene oxide, oxetane, 3,3-bis (chloromethyl) oxetane, tetrahydrofuran, 2-methyltetrahydrofuran and oxeban. Among these alkylene oxides,
From the viewpoints of affinity with polyoxymethylene and easy availability, ethylene oxide and propylene oxide are particularly preferable.

Further, propylene oxide is particularly preferable from the viewpoint of affinity with the olefin compound. These alkylene oxides can be used alone or in combination of two or more. Alternatively, for example, it is possible to first add propylene oxide to alcohol, then add ethylene oxide thereto, and further add propylene oxide.

It is also possible to add propylene oxide and ethylene oxide simultaneously. Number of moles of alkylene oxide added per mole of alcohol or carboxylic acid (n)
Needs to be in the range of 1 to 1,000. In order to improve the lubrication performance of the oxymethylene polymer, n is preferably large, while from the viewpoint of ease of production and purification of an alkylene oxide adduct of alcohol or carboxylic acid, n is preferably small. . With both of these constraints, the most preferred range for n is between 1 and 250.

The number of moles (n) of alkylene oxide added per mole of alcohol or carboxylic acid can be easily measured by quantifying the hydroxyl group at one end of the produced adduct. Next, a method for producing an oxymethylene polymer will be described. The oxymethylene polymer has the general formula

[0029]

[Chemical 10]

(R ₁ , R ₁ ′: selected from hydrogen, an alkyl group and an aryl group, which may be the same or different, and R ₁ and R ₁ ′ bonded to different carbon atoms may also be used. each optionally be the same or different .R _2: an alkyl group, .m = 2 to 6 selected from aryl group, n =. 1 to
Using an alkylene oxide adduct of alcohol or carboxylic acid represented by 1,000) as a chain transfer agent,
Obtained by polymerizing formaldehyde.

The alkyl group represented by R ₁ and R ₁ ′ includes, for example, a methyl group, an ethyl group and a propyl group, and the aryl group represented by R ₁ and R ₁ ′ includes, for example, a phenyl group and a tolyl group. , Xylyl group, etc., and part of the alkyl group or aryl group may be replaced with a halogen compound such as chlorine or fluorine. Examples of the alkyl group represented by R ₂ include a methyl group, an ethyl group, a sec-butyl group, a hexyl group, an octyl group, a decyl group, a lauryl group, a cetyl group and a stearyl group,
Examples of the aryl group represented by R ₂ include a phenyl group, a p-butylphenyl group, a p-octylphenyl group,
There are p-nonylphenyl group, benzyl group, p-butylbenzyl group and the like, and a part of the alkyl group or aryl group may be replaced with a halogen compound such as chlorine or fluorine. The alkylene oxide adduct of alcohol or carboxylic acid is preferably purified by a technique such as distillation, adsorption or drying prior to the polymerization. Further, these compounds can be used alone, or two or more kinds thereof can be mixed and used for polymerization.

For the polymerization of formaldehyde, catalysts generally known as anionic polymerization catalysts, coordinated anionic polymerization catalysts and cationic polymerization catalysts can be used. Typical groups of anionic polymerization catalysts and coordination anionic polymerization catalysts include alkali metals such as sodium and potassium, sodium-naphthalene, alkali metal complex compounds such as potassium-anthracene, alkali metal hydrides such as sodium hydride, and hydrogen. Alkaline earth metal hydrides such as calcium fluoride, sodium methoxide, alkali metal alkoxides such as potassium t-butoxide, sodium caproate,
Carboxylic acid alkali metal salts such as potassium stearate,
Alkaline earth metal salts of carboxylic acids such as magnesium caproate and calcium stearate.

Amines such as n-butylamine, diethylamine, trioctylamine and pyridine, ammonium stearate, quaternary ammonium salts such as tetrabutylammonium methoxide and dimethyl distearyl ammonium acetate, tetramethylphosphonium propionate and trimethylbenzyl. Examples thereof include phosphonium salts such as phosphonium ethoxide, tetravalent organotin compounds such as tributyltin chloride, diethyltin dilaurate and dibutyltin dimethoxide, and 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 acetic anhydrate, boron trifluoride triethylamine complex compounds and other boron trifluoride coordination compounds, perchloric acid, acetyl perchlorate, hydroxyacetic acid, trichloroacetic acid .

Inorganic and organic acids such as p-toluenesulfonic acid, triethyloxonium tetrafluoroborate,
Compound salt compounds such as triphenylmethyl hexafluoroantimonate, aryldiazonium hexafluorophosphate, aryldiazonium tetrafluoroborate,
Examples thereof include alkyl metals such as diethyl zinc, triethyl aluminum and diethyl aluminum chloride.

The oxymethylene polymer is usually polymerized in an organic medium. Examples of the organic medium that can be used for the polymerization include aliphatic hydrocarbons such as n-hexane, n-heptane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated methylene chloride, chloroform and trichloroethylene. Examples include aliphatic hydrocarbons and halogenated aromatic hydrocarbons such as chlorobenzene. These organic media may be used alone or 2
It does not matter if more than one kind is polymerized and used.

The formaldehyde used in the polymerization needs to be substantially anhydrous.
For example, it is necessary to purify using a cold trap method, a solvent washing method, or the like. For the polymerization of oxymethylene polymer,
A conventionally known method such as a blow polymerization method or a solution polymerization method can be used.

The alcohol functioning as a chain transfer agent and the alkylene oxide adduct of carboxylic acid are used by being uniformly dissolved or dispersed in an organic medium. The concentration of the chain transfer agent in the organic medium can be easily determined by experiments depending on the desired molecular weight of the polyacetal polymer. After the polymerization is completed, the polymer is separated from the organic medium, the terminal unstable portion is blocked with, for example, acetic anhydride, and then a stabilizer or the like is added and used as an oxymethylene polymer.

Next, the olefin compound used as the lubricant will be described in detail. The olefin compound that can be used in the present invention is

[0040]

[Chemical 11]

(R ₃ and R ₃ ′ are selected from hydrogen, an alkyl group, an aryl group and an ether group, and they may be the same or different, k = 10 to 500). Is an olefin compound composed of olefin units of Examples of the alkyl group include ethyl group, propyl group, butyl group, hexyl group, octyl group, decyl group, lauryl group, cetyl group and stearyl group, and examples of the aryl group include phenyl group, p-
There are butylphenyl group, p-octylphenyl group, p-nonylphenyl group, benzyl group, p-butylbenzyl group, tolyl group, xylyl group and the like. Further, examples of the ether group include an ethyl ether group, a propyl ether group, a butyl ether group and the like.

From the viewpoint of improving the slidability of the present oxymethylene polymer composition, preferable olefin units include the following.

[0043]

[Chemical 12]

The olefin compound used in the present invention may be a compound composed of one olefin unit or a compound composed of two or more different olefin units. That is, for example, an olefin compound having a block structure or a graft structure composed of a polyethylene unit and a polypropylene unit is also included in the olefin compound of the present invention.

From the viewpoint of improving the slidability of the oxymethylene polymer composition of the present invention, the structure of the olefin compound is preferably a linear structure as compared with the graft structure. Examples of the monomer constituting the olefin compound include ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2- Methyl-2-butene, 1-hexene, 2,3-dimethyl-2-butene, 1
An olefinic monomer represented by heptene, 1-octene, 1-nonene, 1-decene, or allene;
There are diolefin-based monomers represented by 1,2-butadiene, 1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, 1,5-hexadiene, cyclopentadiene and the like.

The olefin compound used in the present invention may be a compound obtained by copolymerizing two or more kinds of these olefinic monomers and diolefinic monomers. When the olefin compound is a compound obtained by polymerizing a diolefin-based monomer, from the viewpoint of improving the thermal stability of the present oxymethylene polymer composition, a carbon-carbon unsaturated bond is formed by using a conventional hydrogenation method. It is preferable to use an olefin compound in which the amount is minimized.

The average degree of polymerization k of the olefin units constituting the olefin compound must be between 10 and 500. When the average degree of polymerization k is less than 10, the long-term lubrication properties of the oxymethylene polymer composition are deteriorated, and the moldability of the mold is also adversely affected. If k is greater than 500, the initial lubricating properties of the present oxymethylene polymer composition will be significantly reduced.

The average degree of polymerization k of the olefin unit is 15 to 15.
It is preferably between 300, and further 20 to 10
It is more preferably between 0. Further, as a preferable olefin compound, an olefin compound modified with an ether group can be used. What is an ether group

[0049]

[Chemical 13]

(R ₄ and R ₄ ′ are selected from hydrogen, an alkyl group and an aryl group, and may be the same or different, and R ₄ and R ₄ ′ bonded to different carbon atoms.
May be the same or different. x = 2
6, y = 1 to 1,000). From the viewpoint of improving the slidability of the oxymethylene polymer composition of the present invention, the polyalkylene oxide unit constituting the ether group is a polyalkylene oxide unit constituting one end of the oxymethylene polymer.

[0051]

[Chemical 14]

More preferably, it is the same as The amount of the olefin compound added to the oxymethylene polymer is
0.3-30 with respect to 100 parts of oxymethylene polymer
It is preferably within the range of parts. If the addition amount is less than 0.3 part, the effect of improving the slidability of the composition is small.
When it is more than 0 part, the moldability and mechanical properties of the composition are remarkably deteriorated. The addition amount of the olefin compound is further preferably 0.5 to 20 parts, and further preferably 2 to 10 parts. These olefin compounds may be used in combination of two or more kinds.

The composition of the present invention may be added with known additives such as a heat stabilizer, a lubricant, a nucleating agent, a release agent, an antistatic agent, in order to impart necessary properties depending on its use and purpose. Surfactants, inorganic fillers and the like can be added within a range that does not impair the object of the present invention. In particular, the addition of the nucleating agent thins the amorphous part near the surface of the molded article obtained from the composition,
It is also very useful for imparting excellent slidability to this molded product.

As the nucleating agent, inorganic nucleating agents such as boron nitride, talc, and pyrophyllite, and organic nucleating agents such as polyoxymethylene having a three-dimensional crosslinked structure can be used. Further, in the oxymethylene polymer composition of the present invention,
A known polyoxymethylene may be added for use.

The polyoxymethylene referred to herein is an oxymethylene unit.

[0056]

[Chemical 15]

A homopolymer consisting of repeating units of the above, a copolymer having a comonomer such as ethylene oxide and propylene oxide inserted into a homopolymer consisting of repeating oxymethylene units, and a copolymer having a three-dimensional crosslinked structure. Is stabilized by a known method against decomposition from the polymer terminal. The addition of polyoxymethylene to the oxymethylene polymer composition of the present invention is a very useful method also from the viewpoint of improving mechanical properties such as flexural modulus and elongation of the resulting composition. .

The oxymethylene polymer composition of the present invention comprises
10 to 1,000 parts are preferable with respect to 100 parts of polyoxymethylene, and further 30 to 300 parts are more preferable.

[0059]

EXAMPLES The present invention will be described below with reference to examples.

[0060]

Example 1 (1) Structure of Oxymethylene Polymer Paraformaldehyde that had been thoroughly dehydrated and dried was heated to 150 ° C.
Then, it was thermally decomposed, and passed through a cooling trap several times to obtain formaldehyde gas having a purity of 99.9%. 110 parts (parts by weight below) of formaldehyde gas per hour, 1.0 × 10 ⁻⁴ mol / l tetrabutylammonium acetate, 5.0 × 10 ⁻³ mol / 1 C
_It was introduced into 500 parts of toluene containing ₁₈ H ₃₇ O (CH ₂ CH ₂ O) ₇₀ H (ethylene oxide adduct to stearyl alcohol, average number of moles of ethylene oxide added: 70, hereinafter abbreviated as S-70).

Simultaneously with the supply of formaldehyde gas
Toluene containing 0 × 10 ⁻⁴ mol / l of tetrabutylammonium acetate and 5.0 × 10 ⁻³ mol / 1 of S-70 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 the polymerization temperature was maintained at 60 ° C. Toluene containing the polymer was continuously withdrawn in accordance with the supply amount, and the polymer was separated by filtration. The polymer was thoroughly washed with acetone and vacuum dried at 60 ° C. to obtain 289 parts of a white polymer. 50 parts of the polyacetal polymer thus obtained was heated with 500 parts of acetic anhydride and 0.1 part of sodium acetate at 139 ° C. for 3 hours, cooled, similarly washed and dried, and 49 parts of the polymer was recovered. (2) Production of composition 100 parts of the above oxymethylene polymer, 0.25 part of 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol) (hereinafter abbreviated as 2246), polycaprolactam / 0.5 parts of a terpolymer of polyhexamethylene adipamide / polyhexamethylene sebacamide (hereinafter abbreviated as PA) and the following olefin compound as a lubricant

[0062]

[Chemical 16]

After adding 3 parts and mixing with a Henschel mixer, the mixture was granulated using a 30 mmφ twin-screw extruder. (3) Further, a molded article for evaluating slidability was molded, and slidability was evaluated by the following method. Sliding property evaluation: The friction coefficient and the wear amount were measured under the following conditions using a Suzuki type friction and wear tester.

Surface pressure: 4 kgf / cm ² (contact area 2 cm ² ) Linear velocity: 6 cm / sec Counterpart material: polyoxymethylene (manufactured by Asahi Chemical Industry Co., Ltd., Tenac <registered trademark> -C4520) 1) Initial lubrication property measurement It is the coefficient of friction immediately after the start (hereinafter abbreviated as μ), and the smaller the value of μ, the better the initial lubrication characteristics.

2) Long-term lubrication property μ after 24 hours of continuous running and wear amount, and the smaller the value of μ and wear amount, the better the long-term lubrication property. The evaluation results are shown in Table 1. Immediately after the start of measurement and after 24 hours, μ was low and the amount of wear was extremely small, and the initial lubrication properties and long-term lubrication properties referred to in the present invention were excellent.

There was no problem with the moldability of this composition, and no rubbing noises, squeaking noises, etc. were generated during the evaluation of slidability.

[0067]

Examples 2 to 14 The same operation and evaluation as in Example 1 were carried out except that the kind and amount of the olefin compound as the lubricant was changed. Tables 1 to 4 collectively show the composition of olefin compounds and the evaluation results. In each of the examples, excellent initial lubrication characteristics and long-term lubrication characteristics were obtained.

[0068]

Examples 15 to 34 S-70 used in the production of the oxymethylene polymer in Example 1 was

[0069]

[Chemical 17]

(Propylene oxide addition product to stearyl alcohol, average addition mole number of propylene oxide: 4
0, hereinafter referred to as S-40)
An oxymethylene polymer was obtained in the same manner as in. Furthermore,
The slidability was evaluated using various olefin compounds as shown in Tables 5-8. In all of the examples, good results were obtained with excellent initial lubrication characteristics and long-term lubrication characteristics.

[0071]

Comparative Example 1 P used as a lubricant in Example 1
Evaluation was carried out in the same manner as in Example 1 except that O-1 was not used. The evaluation results are shown in Table 9. In this comparative example, the performance of the present invention, which has both excellent initial lubrication characteristics and long-term lubrication characteristics, is not obtained.

[0072]

Comparative Example 2 Example 1 was repeated except that the oxymethylene polymer used in Example 1 was replaced with polyoxymethylene homopolymer (Tenac <registered trademark> 5010 manufactured by Asahi Kasei Corporation). It operated similarly and evaluated. The evaluation results are shown in Table 9.

It can be seen that the composition of the present invention has excellent initial lubrication properties, but does not have the excellent long-term lubrication properties referred to in the present invention.

[0074]

Comparative Examples 3 and 4 The procedure of Example 1 was repeated except that the olefin compound (PO-1) used in Example 1 was changed to the olefin compound shown in Table 3. The evaluation results are summarized in Table 9. When the average degree of polymerization k of the olefin unit constituting the olefin compound is less than 10 or more than 500, it is not possible to obtain a composition excellent in initial lubrication properties and long-term lubrication properties according to the present invention.

[0075]

Examples 35 and 36 Polyoxymethylene homopolymer (commercially available from Asahi Kasei Kogyo Co., Ltd.,
Tenac (registered trademark) 5010) was mixed with the composition shown in Table 5 and granulated and molded, and then the slidability and bending characteristics were evaluated. The results of slidability evaluation are summarized in Table 10. Initial lubrication characteristics and long-term lubrication characteristics almost equivalent to those of Example 1 were obtained.

For bending properties, see ASTM D-79.
It measured according to 0. The results are shown in Table 11. Example 3
5 and 36 are those of Example 1 (bending strength 830 kgf / cm ² ,
Bending elastic modulus of 22,000 kgf / cm ² )
It has high bending strength and elastic modulus, and has excellent mechanical properties.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

[Table 3]

[0080]

[Table 4]

[0081]

[Table 5]

[0082]

[Table 6]

[0083]

[Table 7]

[0084]

[Table 8]

[0085]

[Table 9]

[0086]

[Table 10]

[0087]

[Table 11]

[0088]

The composition of the present invention maintains a low coefficient of friction immediately after use for a long period of time, has an extremely small amount of wear, and has excellent slidability which cannot be obtained by conventional polyoxymethylene.

Claims (2)

[Claims] 1. One end of a linear polymer composed of repeating oxymethylene units (A) has the general formula: (R ₁ and R ₁ ′ are selected from hydrogen, an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group and may be the same or different. Also, R ₁ and R ₁ bonded to different carbon atoms may be selected. , R ₁ ′ may be the same or different, and R ₂ is selected from an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group, m = 2 to 6, n
= 1 to 1,000), the number average molecular weight excluding the end groups, which is blocked with a compound selected from the group consisting of an alkylene oxide adduct residue to an alcohol residue and an alkylene oxide adduct residue to a carboxylic acid is 10 1,000
An oxymethylene polymer (B) having the general formula: (R ₃ and R ₃ ′ are selected from hydrogen, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group and an ether group, and they may be the same or different. K =
10-500) and an olefin compound composed of at least one olefin unit. 2. A sliding polyoxymethylene composition comprising polyoxymethylene and the oxymethylene polymer composition according to claim 1.