JP3500453B2 - Polyoxymethylene resin composition having excellent vibration damping properties and molded article thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a resin composition in which a polyoxymethylene resin is simultaneously provided with excellent friction and wear characteristics and extremely high vibration damping performance. The resin composition material is preferably used for applications such as precision equipment, OA equipment, and vibration-proof sliding component materials in the automobile field. The damping property referred to here is, for example, a thickness of 3.0 m.
A dumbbell molded product of m × width 13 mm × length 175 mm was used, one end was fixed, and the radiated sound when the base of the fixed end was hit with an impulse hammer was measured. The frequency response function of the signal and the sound pressure signal of the microphone is obtained. It can be said that the smaller the difference in sound pressure level between the resonance peak and the anti-resonance peak, the better the damping characteristics. The shape of the molded product is not particularly limited, and those having a substantially vibration damping function are included in the molded product according to the present invention. Further, in the present specification, the vibration damping property is defined as the sound pressure peak difference in the evaluation method as described above.

[0002]

2. Description of the Related Art Conventionally, polyoxymethylene resin has been widely used as an engineering resin excellent in mechanical properties and heat resistance for various mechanical parts and OA equipment. In particular, it has been suitably used as a material for gears such as printers because of its excellent friction and wear characteristics. However, with the recent increase in precision and functionality of equipment,
The reduction of vibration and noise generated by equipment is an important issue,
As a material resin, higher vibration damping performance has been required. Generally, as the damping material, a rubber-based or thermoplastic elastomer-based material, or a material in which a resin-based or rubber-based material is sandwiched between metal plates has been used. However, in the former, there is a problem in the heat resistance of the component under high temperature conditions due to heat generation, or the friction and wear characteristics with respect to metal and resin, or the chemical resistance against contact with drugs such as ink, and the like. In the latter, there is a problem in molding.

Further, in JP-A-8-165405, a polymer composition obtained by polymerizing formaldehyde in the presence of a block copolymer of a specific vinyl aromatic compound is disclosed in JP-A-10-60224. Discloses a mixture of a polyoxymethylene resin and a styrenic resin having a functional group, but any of the conventional techniques is intended to improve impact resistance and does not suggest the present invention. .

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances of the prior art, and has a very high vibration damping performance without impairing the excellent friction and wear characteristics of the polyoxymethylene resin. And a polyoxymethylene resin molded part obtained by molding the composition, particularly a gear, a cam, a slider,
It provides mechanical parts such as levers, arms, clutches, joints, shafts, bearings, key stems, key tops, shutters and reels.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have solved the above problems without sacrificing the original properties of polyoxymethylene resins as much as possible, and are polyoxymethylene resins that can satisfy vibration damping performance. As a result of extensive studies to provide a composition, a composition in which a specific thermoplastic elastomer and, if necessary, a lubricant are added to a polyoxymethylene resin has been found to have good friction and wear characteristics and high They have found that they have vibration damping performance and have completed the present invention.

That is, in the present invention, (B) -30 ° C to + 50 ° C per 100 parts by weight of (A) polyoxymethylene resin.
Having a temperature of the main dispersion peak of tan δ obtained by viscoelasticity measurement and having a number average molecular weight of 10,000 to 500,000
1 to 100 parts by weight of the thermoplastic elastomer, which is (C)
A polyoxymethylene resin composition comprising 0 to 10 parts by weight of a lubricant, and a molded article formed by molding the resin composition and having high vibration damping performance, particularly gears, cams and sliders. , Levers, arms, clutches, joints, shafts, bearings, key stems, key tops, shutters, reels and the like.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A detailed description will be given below. The polyoxymethylene resin used as the component (A) in the present invention is obtained by polymerizing a cyclic oligomer such as formaldehyde, its trimer trioxane or tetramer tetraoxane, and containing 100 to 80 mol% of oxymethylene units. And other components of 0 to 20 mol% include ethylene oxide, propylene oxide,
A polymer having a cyclic ether such as 1,3-dioxolane, glycol formal, or diglycol formal, and / or a hydroxyl group, a carboxyl group, an amino group, an ester group, or an alkoxy group, and copolymerizing and / or blocking them. It is a polyoxymethylene copolymer obtained by copolymerization. There are various methods for controlling the molecular weight of the polyoxymethylene copolymer. For example, water, alcohol (for example, methanol), acid (for example, formic acid) or the like may be chain-transferred, hydroxyl group,
A polymer including a carboxyl group, an amino group, an ester group and an alkoxy group may be chain-transferred. If necessary, formal such as methylal may be added at the same time.

A preferred polyoxymethylene resin has an oxymethylene group as a main repeating unit and an oxyalkylene group having 2 or more carbon atoms with respect to the oxymethylene unit in an amount of 0.1 to 5 mol%, more preferably 0.2.
It is a polyoxymethylene copolymer containing ˜3 mol%. Among them, a particularly preferable polyoxymethylene resin is a number average molecular weight of 10,000 represented by the following [Formula 1].
Is a polyoxymethylene block copolymer having a molecular weight of up to 500,000.

[0009]

[Chemical 3] (In the formula, m = 2 except for A (hereinafter referred to as B block)
98 mol%, n = 2 to 98 mol%, m + n = 100 mol%, m is present randomly or in a block with respect to n, and both ends having a number average molecular weight of 500 to 10,000 are hydroxyalkylated. Hydrogenated liquid polybutadiene residue. However, the B block has an iodine value of 20 g-I _2.
It may have an unsaturated bond of 100 g or less. k = an integer selected from 2 to 6, and two k's may be the same or different. R is 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. A
Is a polyoxymethylene copolymer residue represented by the following [Formula 2].

[0010]

[Chemical 4] (R ¹ is 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. J is an integer selected from 2 to 6.
x = 95 to 99.9 mol%, y = 5 to 0.1 mol%, x
+ Y = 100 mol%, y exists randomly with respect to x. ) In [Formula 1], the average number average molecular weight of two A blocks is 5,000 to 250,000. )

The polymerization catalyst is preferably a cationic active catalyst such as Lewis acid, protic acid and its ester or anhydride. Examples of the Lewis acid include boric acid, tin, titanium, phosphorus, arsenic, and antimony halides, and specifically, boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentafluoride, pentachloride. Examples thereof include phosphorus, antimony pentafluoride, and complex compounds or salts thereof. Further, specific examples of the protonic acid, its ester or anhydride include perchloric acid, trifluoromethanesulfonic acid, perchloric acid-tertiary butyl ester, acetyl perchlorate,
Trimethyloxonium hexafluorophosphate and the like can be mentioned. Among them, boron trifluoride; boron trifluoride hydrate; and a coordination complex compound of an organic compound containing an oxygen atom or a sulfur atom and boron trifluoride are preferable, and specifically, boron trifluoride diethyl ether. , Boron trifluoride di-n-butyl ether can be mentioned as a preferred example. The amount of these polymerization catalysts used is 1 × 10 ⁻⁶ mol to 1 mol per 1 mol of the total amount of trioxane and cyclic ether and / or cyclic formal. × 10 ^-3 mol is preferable, 5 × 1
More preferably, it is 0 ⁻⁶ mol to 1 × 10 ⁻⁴ mol.

The polymerization method is not particularly limited, but for example, bulk polymerization can be mentioned, and this bulk polymerization may be either batch type or continuous type. In this bulk polymerization, it is general to use a monomer in a molten state and obtain a solid bulk polymer as the polymerization proceeds.

The deactivation of the polymerization catalyst in the polymerized polyoxymethylene copolymer is carried out by using the polyoxymethylene copolymer obtained by the above-mentioned polymerization reaction with amines such as ammonia, triethylamine and tri-n-butylamine. , Or an alkali metal or alkaline earth metal hydroxide, inorganic acid salt, an organic acid salt or the like is added to an aqueous solution or an organic solvent solution containing at least one catalyst neutralizing deactivator, and generally in a slurry state. Is performed by stirring for several minutes to several hours. The slurry after catalyst neutralization and deactivation is filtered and washed to remove unreacted monomer, catalyst neutralization and deactivator, and catalyst neutralization and deactivation salt, and then dried.

Further, a method of deactivating the polymerization catalyst by contacting vapor of ammonia, triethylamine or the like with the polyoxymethylene copolymer, or a method of deactivating the polymerization catalyst, at least one of hindered amines, triphenylphosphine, calcium hydroxide and the like A method of deactivating the catalyst by bringing the oxymethylene copolymer into contact with a mixer can also be used.

Next, the terminal stabilization treatment of the polyoxymethylene copolymer after deactivation of the polymerization catalyst will be described. As a method for decomposing and removing the unstable terminal portion, for example, a single-screw extruder with a vent, a twin-screw extruder with a vent, or the like is used, and ammonia, an aliphatic amine such as triethylamine, tributylamine, or hydroxylation is used. Polyoxymethylene copolymer in the presence of a basic substance capable of decomposing unstable terminal portions such as alkali metal or alkaline earth metal hydroxides represented by calcium, weak inorganic salts, weak organic salts, etc. Can be melted, and the unstable end portion can be decomposed and removed. Among them, particularly preferable one is the following [formula 3].
Is a method of treating a thermally unstable terminal with at least one quaternary ammonium compound represented by
In the polyoxymethylene copolymer stabilized by the above method, almost no unstable terminal portion remains.

[Formula 3] [R ² R ³ R ⁴ R ⁵ N ⁺ ] _n X ^n- (wherein R ² , R ³ , R ⁴ and R ⁵ each independently have 1 to 30 carbon atoms). An unsubstituted alkyl group or a substituted alkyl group; an aryl group having 6 to 20 carbon atoms; an unsubstituted alkyl group or a substituted alkyl group having 1 to 30 carbon atoms is substituted with at least one aryl group having 6 to 20 carbon atoms An aralkyl group; or an alkylaryl group in which an aryl group having 6 to 20 carbon atoms is substituted with at least one unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group, and the unsubstituted alkyl group or the substituted alkyl group is A straight-chain, branched, or cyclic hydrogen atom may be substituted with halogen in the above-mentioned unsubstituted alkyl group, aryl group, aralkyl group, and alkylaryl group, and n represents an integer of 1 to 3. X Is a hydroxyl group or 1 carbon atom Represents an acid residue of a carboxylic acid of ˜20, a hydrogen acid, an oxo acid, an inorganic thio acid, or an organic thio acid of 1 to 20 carbon atoms.

Specific examples of the quaternary ammonium salt compound include tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetra-n-butylammonium, cetyltrimethylammonium, tetradecyltrimethylammonium, 1,
6-hexamethylenebis (trimethylammonium),
Decamethylene-bis- (trimethylammonium), trimethyl-3-chloro-2-hydroxypropylammonium, trimethyl (2-hydroxyethyl) ammonium, triethyl (2-hydroxyethyl) ammonium, tripropyl (2-hydroxyethyl) ammonium, tri -N-butyl (2-hydroxyethyl) ammonium, trimethylbenzylammonium, triethylbenzylammonium, tripropylbenzylammonium, tri-n-butylbenzylammonium, trimethylphenylammonium, triethylphenylammonium, trimethyl-2-oxyethylammonium,
Hydroxides such as monomethyltrihydroxyethylammonium, monoethyltrihydroxyethylammonium, octadecyltri (2-hydroxyethyl) ammonium, tetrakis (hydroxyethyl) ammonium;
Hydrohalides other than halogenated such as hydrogen azide; sulfuric acid, nitric acid, phosphoric acid, carbonic acid, boric acid, chloric acid, iodic acid, silicic acid, perchloric acid, chlorous acid, hypochlorous acid, chlorosulfuric acid, amide Oxo acid salts such as sulfuric acid, disulfuric acid and tripolyphosphoric acid; thio acid salts such as thiosulfuric acid; formic acid, acetic acid, propionic acid, butanoic acid, isobutyric acid, pentanoic acid, caproic acid, caprylic acid,
Examples thereof include carboxylic acid salts such as capric acid, benzoic acid and oxalic acid. Among them, the hydroxide (OH ^-), sulfuric acid (H
_{^{SO 4 -, SO 4 2-)}} , carbonate (HCO ₃ ^-, C
Salts of O ₃ ²⁻ ), boric acid (B (OH) ₄ ⁻ ) and carboxylic acid are preferable. Of the carboxylic acids, formic acid, acetic acid, and propionic acid are particularly preferable. These quaternary ammonium compounds may be used alone or in combination of two or more. The amount of the quaternary ammonium compound added is 0.05 to 50 ppm by weight in terms of the amount of nitrogen derived from the quaternary ammonium compound represented by the following formula (4) with respect to the polyoxymethylene copolymer. Is.

P × 14 / Q (4) (In the formula, P represents the concentration (weight ppm) of the quaternary ammonium compound relative to the polyoxymethylene copolymer,
14 is the atomic weight of nitrogen, and Q is the molecular weight of the quaternary ammonium compound. Next, the thermoplastic elastomer which is the component (B) will be described. The thermoplastic elastomer referred to in the present invention is one or more selected from polyolefin elastomers, styrene elastomers, polyester elastomers, polyamide elastomers, and polyurethane elastomers, and is used for copolymerization of random, block, graft, etc. Although there is no particular limitation such as morphology, presence or absence of side chains or branches and their degree, proportion of copolymerization composition, presence or absence of hydrogenation, the temperature of the main dispersion peak of tan δ obtained by viscoelasticity measurement is −30 ° C. to + 50 ° C., More preferably -20 to + 40 ° C
It must be: Even if the temperature of the main dispersion peak of tan δ is less than −30 ° C. or exceeds + 50 ° C., sufficient vibration damping performance cannot be obtained. Further, regarding the molecular weight of the thermoplastic elastomer, a number average molecular weight of 10,000 to 500,000 is required, and if it is out of the above range, high vibration damping performance cannot be obtained. Particularly preferable is that the value of tan δ at room temperature of 23 ° C. is 0.2 or more at the same time. More preferably, when the weight loss due to thermal decomposition using a thermobalance was measured at a heating rate of 10 ° C./min in a nitrogen stream, it was 75% at 350 ° C.
It has the above weight retention rate. Further, among the thermoplastic elastomers, a preferable one is a copolymer of a styrene-based monomer shown below and a monomer copolymerizable with the styrene-based monomer. Examples of the styrene-based monomer include styrene, α-methylstyrene, 2,4-dimethylstyrene, p-methylstyrene, t-butylstyrene,
It contains an aromatic vinyl monomer such as chloromethylstyrene and ethylstyrene, and styrene is preferable among them. Further, the monomer copolymerizable with the styrene-based monomer includes not only a copolymerizable unsaturated monomer but also an elastomer and the like, and examples of the copolymerizable monomer include (meth) acrylonitrile. , (Meth) acrylic acid ester, maleimide-based monomer, diene monomer (eg, butadiene, isoprene, etc.), olefin (eg, ethylene, propylene, butene, etc.) and the like. Examples of the elastomer include polybutadiene, polyisoprene, ethylene-propylene rubber, acrylic rubber, halogenated polyolefin such as chlorinated polyethylene, and the like,
It may be a hydrogenated substance.

Particularly preferred as the thermoplastic elastomer is a block (a) made of a vinyl aromatic monomer having a number average molecular weight of 2500 or more and isoprene or isoprene-butadiene, and vinyl having 3,4 bonds and 1,2 bonds. A styrene elastomer composed of the block (b) having a bond content of 20% or more, preferably 40% or more, and further preferably a styrene elastomer composed of two or more components (a).
The thermoplastic elastomer is 1 to 100 parts by weight, preferably 5 to 80 parts by weight, and more preferably 10 to 100 parts by weight of the polyoxymethylene resin as the component (A).
By adding 60 parts by weight, the desired performance can be exhibited. If it is less than 1 part by weight or more than 100 parts by weight, both good friction and wear characteristics and vibration damping performance cannot be satisfied at the same time.

As a component other than (A) and (B), a polyolefin resin is simultaneously added to 0.1 to 100 parts by weight, preferably 1 to 100 parts by weight based on 100 parts by weight of the components (A) and (B). 60 parts by weight, more preferably 5 to 50 parts by weight may be used in combination. Examples of the polyolefin resin include homopolymers of olefin monomers such as polyethylene, polypropylene, polybutylene, and polyisobutylene, and ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-octene copolymers, and the like.
-Olefin-based polymers may be mentioned, and they may be modified with an unsaturated carboxylic acid such as maleic acid or nadic acid or an acid anhydride thereof.

Next, additives that can be further added to the polyoxymethylene resin composition of the present invention will be described. In the range of 0.01 to 0.2 parts by weight, two or more kinds selected from calcium difatty acids having 12 to 22 carbon atoms are further added to the total 100 parts by weight of the components (A) and (B). Then, a composition more suitable for the requirements of the present application is obtained. Additives other than the above may be added as desired. For example, antioxidants, hindered amines, polyamides, melamine, melamine derivatives, poly-β-alanine copolymers, ultraviolet absorbers, glass fibers, talc, wollastonite, inorganic fillers such as hydrotalcite, conductive carbon black, pigments, Crystal nucleating agents, lubricants, release agents, antistatic agents, etc. Particularly, regarding the antioxidant, it is preferable to add triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] within the range of 0.1 to 1.0 part by weight.

The lubricant as the component (C) has a silicone compound and / or a number average molecular weight of 100 to 50.
No. 00 alkylene glycol-based copolymer and liquid ethylene-α-olefin random copolymer, and the addition amount thereof is 0 to 10 parts by weight, preferably 0.1 to 10 parts by weight. Parts by weight, more preferably 1 to 5 parts by weight.

[0023]

EXAMPLES The present invention will be described in detail below with reference to examples. In addition, each measured value in an Example was calculated | required by the following method. The temperature and numerical value of the main dispersion peak of tan δ obtained by viscoelasticity measurement were determined by measuring the viscoelasticity spectrum with Rheovibron (manufactured by Orientec Co., Ltd.). The microstructure was measured by NMR spectrum, 4.
From the ratio of the peaks of 3.4 bond and 1.2 bond at 8 ppm and 5.8 ppm and the peak of 1.4 bond at 5.3 ppm,
The contents of 3.4 bonds and 1.2 bonds were calculated.

Regarding the damping property, a dumbbell injection molded product having a thickness of 3.0 mm, a width of 13 mm and a length of 175 mm was used in an anechoic chamber, one end was fixed, and the root of the fixed end was fixed. It is a measurement of the radiated sound when hit with an impulse hammer, and the acoustic analysis system manufactured by Ono Sokki Co., Ltd. is used to obtain the frequency response function of the exciting force signal of the hammer and the sound pressure signal of the microphone. . The difference in sound pressure level between the second resonance peak and the second anti-resonance peak was measured, and it can be said that the smaller the value, the better the damping characteristics.

For friction and wear characteristics, pitch circle diameter 6
After molding a 0 mm gear and leaving it at 23 ° C. and 50% RH for 24 hours, set a gear made of Tenac-C4520, which is a commercially available general polyacetal resin copolymer, on the drive side using a gear durability tester manufactured by Toshiba Corporation. Then, set the evaluation sample on the driven side and set the rotation speed on the pitch circle to 0.5 m.
/ S, torque was set to 4.5 kgf-cm, and continuous operation was performed in a 23 ° C., 50% RH atmosphere for 96 hours. The weight loss (mg) of both the driving side gear and the driven side gear at this time was taken as the amount of wear, and the frictional wear characteristics were taken. The lower this value, the better the friction and wear characteristics. Regarding the shape of the gear, the pitch circle diameter is 60 mm, the module 1, the number of teeth is 60, and the pressure angle is 2.
0 degree, tooth width 5 mm, web thickness 2 mm, helix angle 0
A spur gear with a weight of about 10g.

[Contents of ingredients used] A. Polyoxymethylene resin A-1: 6 5 liter jacket type polymerization tank with stirring blade
The temperature was adjusted to 0 ° C., 1.0 × 10 ⁻⁴ mol / L tetrabutylammonium acetate was used as a polymerization catalyst, and 5.0 × 10 ⁻³ mol / L C ₁₈ H ₃₇ O (CH ₂ C) was used as a chain transfer agent.
H ₂ O) ₄₀ H (ethylene oxide adduct to stearyl alcohol) containing toluene was fed at 5 L / hr, and virtually anhydrous formaldehyde at 35 mol / h.
Polymerization is carried out by continuously supplying at r. After the obtained polymer is filtered, acetic anhydride is supplied so that the slurry concentration becomes 25 wt% and esterification is performed at 145 ° C. for 2 hours. This was filtered, washed with acetone, and then dried at 120 ° C. to obtain a polyoxymethylene block polymer. To 100 parts by weight of this block polymer, 0.2 of 2,2'-methylene-bis- (4-methyl-6-t-butylphenol) was added.
After adding 5 parts by weight, the mixture was supplied to a twin screw type extruder with a vent. After melt-kneading with an extruder, it was extruded as a strand from an extruder die part and pelletized.

A-2: A biaxial paddle type continuous polymerization machine with a jacket capable of passing a heat medium was adjusted to 80 ° C., and 40 mol / hr of trioxane containing water and formic acid = 4 ppm was adjusted.
At the same time, 1,3-dioxolane as a cyclic formal was supplied to the polymerization machine at 0.7 mol / hr, and boron trifluoride di-n-butyl etherate dissolved in cyclohexane as a polymerization catalyst was added to 5 mol per 1 mol of trioxane. × 10
^-5 so that the mole, also was methylal _{[(CH 3 O) 2 CH} 2] trioxane 1 mol 2 × and ^10-3 continuously fed so that the mole polymerization as chain transfer agents. The polymer discharged from the polymerization machine was put into a 1% aqueous solution of triethylamine to completely deactivate the polymerization catalyst, and then the polymer was filtered and washed, and 1 part by weight of a crude polyoxymethylene copolymer after filtration and washing On the other hand, as the quaternary ammonium compound, triethyl (2-hydroxyethyl) ammonium formate was added using the above formula (4) so as to be 20 ppm by weight in terms of nitrogen amount and mixed uniformly. After that, it was dried at 120 ° C.

Next, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] as an antioxidant was added to 100 parts by weight of the dried crude polyoxymethylene copolymer in an amount of 0.1.
3 parts by weight, 0.02 part by weight of calcium stearate and 0.02 part by weight of calcium behenate were added and supplied to a twin screw type extruder with a vent. If necessary, water and / or triethylamine are added to the molten polyoxymethylene copolymer in the extruder, and the unstable terminal portion is decomposed at a preset temperature of the extruder of 200 ° C. and a residence time of 5 minutes in the extruder. I went. The decomposed polyoxymethylene copolymer at the unstable terminal portion was devolatilized under the conditions of a vent vacuum degree of 20 Torr, extruded as a strand from the extruder die portion, and pelletized.

A-3: A jacketed twin-screw paddle type continuous polymerization machine capable of passing a heat medium was adjusted to 80 ° C., and 40 mol / hr of trioxane containing water and formic acid = 4 ppm was adjusted.
At the same time, 1,3-dioxolane as a cyclic formal was supplied to the polymerization machine at 2 mol / hr, and boron trifluoride di-n-butyl etherate dissolved in cyclohexane as a polymerization catalyst was dissolved in 5 × 10 5 to 1 mol of trioxane. ^{ー 5}
In a molar amount and as a chain transfer agent, 1 × 1 of hydrogenated polybutadiene having hydroxyl groups at both ends represented by the following formula (5) (Mn = 2330) was added to 1 mol of trioxane.
Polymerization was carried out by continuously feeding so that the amount became 0 to ³ mol. Other than the above, the same operation as in Example 1 was carried out to obtain a polyoxymethylene copolymer.

[0030]

[Chemical 5] B. Thermoplastic Elastomer B-1: Styrene-Vinyl Polyisoprene-Styrene Copolymer (trade name "HYBLER VS-1", Kuraray Co., Ltd.
Made by the company. tan δ peak temperature = 20 ° C.) B-2: Styrene-hydrogenated vinyl polyisoprene-styrene copolymer (trade name “HIBLER HVS-3”, manufactured by Kuraray Co., Ltd. tan δ peak temperature = −5 ° C.) B-3 : Styrene-polyethylene / butylene-styrene copolymer (trade name "Tuftec H1041", manufactured by Asahi Kasei Co., Ltd. tanδ peak temperature = -50 ° C) B-4: polystyrene (trade name "G8702", Asahi Kasei Kogyo ( Co., Ltd. tan δ peak temperature = 100 ° C)

[0031]

Example 1 A-1 was used as a polyoxymethylene resin.
00 parts by weight, 20 B-1 as a thermoplastic elastomer
Parts by weight were blended with a Henschel mixer and extruded with a vented twin-screw extruder for kneading. The extruded resin was made into pellets with a strand cutter.
The pellets were dried at 80 ° C. for 3 hours and then molded into a desired shape using an injection molding machine, and the vibration damping property and the friction and wear characteristics were measured. The results are shown in Table 1.

[0032]

[Examples 2 to 8] Polyoxymethylene resin and a thermoplastic elastomer were blended under the conditions shown in Table 1, blended with a Henschel mixer, and then the same operation as in Examples was carried out to measure the vibration damping property and the friction and wear characteristics. did. The results are shown in Table 1.

[Comparative Examples 1 to 3] Under the conditions shown in Table 2, after blending a polyoxymethylene resin and a thermoplastic elastomer and blending them with a Henschel mixer, the same operation as in the example is carried out to measure the vibration damping property and the friction and wear characteristics. did. The results are shown in Table 2.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

The composition of the present invention, which is characterized in that a specific thermoplastic elastomer in a polyoxymethylene copolymer and, if necessary, a lubricant are used in combination, has good friction and wear properties and high It can satisfy vibration damping performance at the same time and can be used especially as a material for anti-vibration sliding parts, and is particularly effective as a material for gears in precision instruments, office automation equipment, automobile fields and the like.

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Claims (12)

(57) [Claims] 1. A temperature of the main dispersion peak of tan δ obtained by viscoelasticity measurement at (B) -30 ° C. to + 50 ° C. with respect to 100 parts by weight of (A) polyoxymethylene resin.
1 to 100 parts by weight of a thermoplastic elastomer having a number average molecular weight of 10,000 to 500,000 and (C) a lubricant of 0 to 1
A polyoxymethylene resin composition comprising 0 part by weight of the polyoxymethylene resin composition. 2. The tan obtained by the viscoelasticity measurement at 23 ° C. of the thermoplastic elastomer according to claim 1.
2. The numerical value of δ is 0.2 or more.
The polyoxymethylene resin composition described. 3. The polyoxymethylene resin of (A) according to claim 1, wherein the oxymethylene group is a main repeating unit, and the oxyalkylene group having 2 or more carbon atoms is contained in an amount of 0.1 to 5 with respect to the oxymethylene unit. The polyoxymethylene resin composition according to claim 1 or 2, which is a polyoxymethylene copolymer containing mol%. 4. The polyoxymethylene resin composition according to claim 1, wherein the thermoplastic elastomer (B) according to claim 1 is a styrene elastomer. 5. The styrene elastomer according to claim 4, which comprises a block (a) made of a vinyl aromatic monomer having a number average molecular weight of 2500 or more and isoprene or isoprene-butadiene, and has 3,4 bonds and 1,2 bonds. The polyoxymethylene resin composition according to claim 4, which is composed of the block (b) having a content of 20% or more. 6. The polyoxymethylene resin composition according to claim 5, wherein the styrene elastomer according to claim 5 is composed of two or more block (a) components. 7. The polyoxymethylene resin according to claim 1, wherein the polyoxymethylene resin has at least one hydroxyl group, carboxyl group, amino group, ester group or alkoxy group and has a number average molecular weight of 400 or more. 7. A polyoxymethylene resin composition according to any one of claims 1 to 6, which is a polyoxymethylene block copolymer obtained by chain transfer of the polymer of claim 1. 8. The polyoxymethylene block copolymer according to claim 7, which is a polyoxymethylene block copolymer represented by the following [formula 1] and having a number average molecular weight of 10,000 to 500,000. Item 7. A polyoxymethylene resin composition according to item 7. [Chemical 1] (In the formula, m = 2 except for A (hereinafter referred to as B block)
98 mol%, n = 2 to 98 mol%, m + n = 100 mol%, m is present randomly or in a block with respect to n, and both ends having a number average molecular weight of 500 to 10,000 are hydroxyalkylated. Hydrogenated liquid polybutadiene residue. However, the B block has an iodine value of 20 g-I _2.
It may have an unsaturated bond of 100 g or less. k = an integer selected from 2 to 6, and two k's may be the same or different. R is 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. A
Is a polyoxymethylene copolymer residue represented by the following [Formula 2]. [Chemical 2] (R ¹ is 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. J is an integer selected from 2 to 6.
x = 95 to 99.9 mol%, y = 5 to 0.1 mol%, x
+ Y = 100 mol%, y exists randomly with respect to x. ) In [Formula 1], the average number average molecular weight of two A blocks is 5,000 to 250,000. ) 9. The (A) polyoxymethylene resin according to claim 1, wherein at least one quaternary ammonium compound represented by the following [formula 3] is used to treat the thermally unstable terminal. The polyoxymethylene resin composition according to claim 1, wherein the polyoxymethylene resin composition is stabilized. [Formula 3] [R ² R ³ R ⁴ R ⁵ N ⁺ ] _n X ^n- (In the formula, R ² , R ³ , R ⁴ , and R ⁵ are each independently an unsubstituted group having 1 to 30 carbon atoms. An alkyl group or a substituted alkyl group; an aryl group having 6 to 20 carbon atoms; an aralkyl group in which an unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group is substituted with at least one aryl group having 6 to 20 carbon atoms; Or an alkylaryl group in which an aryl group having 6 to 20 carbon atoms is substituted with at least one unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group, and the unsubstituted alkyl group or the substituted alkyl group is a straight chain In the above-mentioned unsubstituted alkyl group, aryl group, aralkyl group and alkylaryl group, a hydrogen atom may be replaced by halogen, n represents an integer of 1 to 3, X represents a hydroxyl group, Or cal having 1 to 20 carbon atoms It represents an acid residue of boric acid, hydrogen acid, oxo acid, inorganic thio acid, or organic thio acid having 1 to 20 carbon atoms.) 10. A component obtained by subjecting the resin composition according to any one of claims 1 to 9 to injection molding or extrusion molding, and cutting if necessary. 11. The polyoxymethylene resin composition according to claim 10, wherein the component according to claim 10 is at least one selected from the group consisting of a mechanical component, an outsert-molded resin component, a chassis, a tray, a side plate and the like. Parts of things. 12. The mechanical component according to claim 11 is a gear,
Cam, slider, lever, arm, clutch, joint,
The component of the polyoxymethylene resin composition according to claim 11, which is at least one selected from the group consisting of shafts, bearings, key stems, key tops, shutters, reels and the like.