JP2002138186A - Polyacetal resin composition and molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyacetal resin having high strength and excellent sliding property, especially keeping very low level of sliding noise such as creaky noise, and having excellent dimensional stability. SOLUTION: This polyacetal resin composition comprises 0.05 to 20 pts.wt. of a mixture of (1) acrylic modified polyorganosiloxane obtained by graft copolymerising acrylic acid ester and/or methacrylic acid ester and if necessary a monomer copolymerizable with these to a polyorganosiloxane, and (2) unmodified polyorganosiloxane having dynamic viscosity of 100,000 cSt to 10,000,000 cSt, added to 100 pts.wt. of a polyoxymethylene copolymer having oxymethylene group as the principal repeating unit and an oxyalkylene group having 2 or more carbons.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyacetal resin composition having high strength, excellent slidability, and reduced noise generated during sliding, and a molded article. The composition comprises:
OA equipment parts, information equipment parts, home appliance parts, automobile parts,
It is formed into resin gears, mechanical parts, etc., which are applied to clothing, stationery, sundries, building materials, and the like.

[0002]

2. Description of the Related Art Polyacetal resins are engineering plastics having excellent mechanical strength, fatigue resistance, slidability, chemical resistance, etc., and include OA equipment parts, information equipment parts, home appliance parts, automobile parts, clothing, It is widely used as a material for resin gears, mechanical parts, and the like, which is applied to stationery, miscellaneous goods, building materials, and the like. Among them, in addition to the above characteristics, mass production is possible at low cost and the like, so that they are widely used as gear materials. In recent years, main performances required for gear materials include high strength, low noise, low wear, and high accuracy. The high strength required for the resin gear means that the torque transmission capability is high, and relates to the mechanical strength of the gear material. For example, it is conceivable to improve the mechanical strength by blending a reinforcing filler such as an inorganic filler such as glass fiber, carbon fiber, potassium titanate whisker, calcium carbonate, and talc into a polyacetal resin. In addition, since the reinforcing filler is harder than the polyacetal resin, the reinforcing filler scrapes the polyacetal resin during sliding, resulting in a large amount of wear. Also,
Homopolymers and copolymers exist in polyacetal resins.Polyacetal homopolymers have higher mechanical strength than polyacetal copolymers, but have large post-shrinkage due to the progress of crystallization, resulting in poor dimensional stability and high precision. Not suitable for gears.

[0003] Next, regarding the low noise performance required for resin gears, usually, sliding between polyacetal resins involves the following.
There is a problem that sliding noise such as squeaking noise is loud. In order to improve this, and also to improve wear resistance,
It is conceivable to mix a slidability improver such as a lubricant, a lubricant, and a release agent with the polyacetal resin, but generally, when these slidability improvers are added, the physical properties of the material are reduced,
It is not appropriate because it causes a decrease in the tooth root strength. Some types of the slidability improver adversely affect the dimensional stability. Furthermore, depending on the type and the amount of these slidability improvers, the surface of the molded product is peeled off, or the slidability improver bleeds out during molding, and the mold deposit adhered to the mold increases. There is a problem.

In order to solve the above problems, Japanese Patent Laid-Open No.
JP-A-93168 discloses that a polyorganosiloxane contains an acrylate and / or a methacrylate (hereinafter may be abbreviated as “(meth) acrylate”) and a monomer copolymerizable therewith. It has been proposed that an acrylic-modified polyorganosiloxane obtained by graft copolymerizing the above mixture is blended in a specific range. However, when added in large amounts, the strength decreases,
When the amount is small, there is a disadvantage that the slidability is not sufficiently exhibited.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyacetal resin which has high strength and excellent slidability, and in particular, has very little sliding noise such as squeaking noise.

[0006]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies and as a result, have found that a polyoxymethylene copolymer containing an oxymethylene group as a main repeating unit and containing an oxyalkylene group having 2 or more carbon atoms. The above-mentioned polyacetal is obtained by blending an appropriate amount of a mixture of an acrylic-modified polyorganosiloxane and a specific unmodified polyorganosiloxane, which has good compatibility and has a large effect of improving slidability even when added in a small amount. It has been found that there is little decrease in the mechanical properties of the resin, high strength and excellent slidability, especially very little sliding noise such as squeaking noise, excellent dimensional stability, and good appearance of the molded product. . In the present invention, it is more preferably effective that the polyacetal resin is a polyoxymethylene copolymer containing 0.5 to 3.0% by weight of an oxyalkylene group having 2 or more carbon atoms.

Hereinafter, the present invention will be described in detail. Polyacetal resin The polyacetal resin used in the present invention is a resin mainly composed of a polyoxymethylene copolymer. Such a polyoxymethylene copolymer has an oxymethylene group as a main repeating unit and has an oxyalkylene having 2 or more carbon atoms. It is a copolymer containing a oxyalkylene group, preferably a copolymer containing 0.5 to 3.0% by weight of the oxyalkylene group. Specifically, formaldehyde or trioxane which is a cyclic oligomer thereof is used as a main monomer, and ethylene oxide, propylene oxide, 1,3-
Dioxolan, 1,3,5-trioxepane, 1,4-
Butanediol formal, as at least one comonomer one or more selected from among cyclic ethers and / or cyclic acetal with a carbon-carbon bond, such as diethylene recall formal, obtained by copolymerizing in the presence of a cationic catalyst It is something that can be done. In order to obtain good comonomer dispersibility, it is particularly preferable to use 1,3-dioxolane and / or 1,3,5-trioxepane which does not cause chain transfer in the polymer. The polyoxymethylene copolymer used in the present invention contains an oxyalkylene group, and preferably has an oxyalkylene group unit introduced into the copolymer of preferably 0.5 to 3.0.
%, More preferably 0.6 to 2.0% by weight, most preferably 0.7 to 1.6% by weight. If the comonomer content is too low, the copolymer will be insufficiently stable against heat or chemicals and the long-term durability of various properties such as gear strength and precision will be poor.If it is excessive, the strength and rigidity will decrease. In any case, the object of the present invention cannot be satisfied, which is not preferable.

In order to control the molecular weight of the polyoxymethylene copolymer in the present invention, a chain transfer agent is added if necessary. Examples of such a chain transfer agent include methylal, ethylal, butyral, and the like. The amount of the chain transfer agent to be added is adjusted in the range of 0 to 1000 ppm according to the required molecular weight.

As the polymerization catalyst for producing the polyoxymethylene copolymer used in the present invention, a general cation-active catalyst is used. Such cationically active catalysts include Lewis acids, especially boron, tin, titanium, phosphorus, halides such as arsenic and antimony, for example, boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentachloride,
Compounds such as phosphorus pentafluoride, arsenic pentafluoride and antimony pentafluoride and their complex compounds or salts, protonic acids,
For example, trifluoromethanesulfonic acid, perchloric acid,
Esters of protic acids, especially esters of perchloric acid with lower aliphatic alcohols (eg tertiary butyl ester of perchloric acid), anhydrides of protic acids, especially mixed anhydrides of perchloric acid with lower aliphatic carboxylic acids (especially Acetyl perchlorite), or isopoly acid, heteropoly acid,
(For example, phosphomolybdic acid), or triethyloxonium hexafluorophosphate, triphenylmethylhexafluoroarsenate, acetylhexafluoroborate and the like. Among them, boron trifluoride and a coordination compound of boron trifluoride and an organic compound (for example, ethers) are the most common and suitable. These catalysts are generally used in an amount of 10 to 10
300 ppm is used.

The production of the polyoxymethylene copolymer used in the present invention can be carried out by the same equipment and method as the conventionally known trioxane copolymerization method. That is, a batch type, a continuous type, any method is also possible, and may be any of melt polymerization, solution bulk polymerization, etc., using a liquid monomer,
A continuous bulk polymerization method for obtaining a polymer in the form of a solid powder as the polymerization proceeds is industrially common and desirable. In this case, if necessary, an inert liquid catalyst may coexist. As a polymerization apparatus, a co-kneader, a twin-screw continuous extrusion mixer, a twin-screw paddle-type continuous mixer, or a continuous polymerization apparatus for trioxane specified by this can be used. It may be divided into. In particular, those having a pulverizing function such that a solid polymer produced by a polymerization reaction can be obtained in a fine form are preferable. The polymerization temperature is generally in the temperature range of 64-120C. In particular, it is preferable that the polymerization is performed at a relatively low temperature in such a temperature range. Further, the polymerization time is related to the amount of the catalyst, and is not particularly limited.
Is selected. After a predetermined time, the crude polymer discharged from the polymerization machine must be immediately mixed and contacted with a deactivator to deactivate the polymerization catalyst. Examples of the deactivator include a solution in which amines such as triethylamine and triethanolamine and inorganic alkaline substances such as sodium fluoride and potassium fluoride are mixed. As the solution, an aqueous solution is particularly preferable. The copolymer in which the polymerization catalyst has been deactivated is subjected to a terminal stabilization step through washing, separation and recovery of unreacted monomers, drying if necessary, or, if necessary, further decomposition and removal of unstable terminals. Through,
In addition, additives such as various stabilizers are added and melt-kneaded into pellets to obtain products.

The polyoxymethylene copolymer used in the present invention may contain various stabilizers and, if desired, a processability improver. Organic compounds used as stabilizers and / or processability improvers include, for example, 2,2′-methylenebis (4-methyl-
6-t-butylphenol), 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-di- t-butyl-4-hydroxyphenyl) propionate], triethylene glycol bis [3- (3-t-butyl-5-methyl-4)
-Hydroxyphenyl) propionate], 1,3,5
-Trimethyl-2,4,6-tris (3,5-di-t-
Butyl-4-hydroxybenzyl) benzene, n-octadecyl-3- (4'-hydroxy-3 ', 5'-di-
t-butylphenyl) propionate, 4,4′-methylenebis (2,6-di-t-butylphenol), 4,
4'-butylidenebis- (6-t-butyl-3-methylphenol), 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1 , 1-dimethylethyl 2,4,8,
10-tetraoxaspiro [5,5] undecane, di-
Stearyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, 2-t-butyl-6- (3-t
-Butyl-5-methyl-2-hydroxybenzyl) -4
-Methylphenyl acrylate, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-
Antioxidants represented by hindered phenols such as hydrocinnamamide), nylon 6,10, nylon 6,
66,610, polyamides such as polyacrylamide, nitrogen-containing compounds typified by polycondensates with melamine, dicyandiamide and the like, higher fatty acids such as stearic acid such as sodium, potassium, magnesium, calcium and barium, and hydroxyl groups. Heat-resistant stabilizers represented by metal-containing compounds such as salts of substituted higher fatty acids having a substituent, 2- [2-hydroxy-3,5-bis-
(Α, α′-dimethylbenzyl) phenyl] benzotriazole and the like, 2-hydroxy-
UV absorbers represented by benzophenones such as 4-methoxybenzophenone, and 4-acetoxy-2,
2,6,6-tetramethylpiperidine, bis (2,2,
Light stabilizers represented by hindered amines such as 6,6-tetramethyl-4-piperidyl) adipate; higher fatty acid esters such as glycerin monostearate and pentaerythritol tristearate; and higher such as ethylenebis (stearylamide) It is at least one selected from lubricants represented by fatty acid amides, plasticizers such as polyethylene glycol and polyoxyethylene polypropylene copolymer. Among them, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4) is used as an antioxidant.
-Hydroxyphenyl) propionate], triethylene glycol bis [3- (3,5-di-t-butyl-4)
-Hydroxyphenyl) propionate], 3,9-bis- {2- [3- (3-t-butyl-4-hydroxy-
5-methylphenyl) flopionyloxy-] 1,1-
Hindered phenols such as dimethylethyl {-2,4,8,10-tetraoxaspiro [5,5] undecane; polycondensation with melamine, dicyandiamide and the like as nitrogen-containing compounds and formaldehyde; magnesium as a metal-containing compound , Calcium higher fatty acids and salts of substituted higher fatty acids are preferred compounds. The total amount of the compound added as a stabilizer to the resin material mainly comprising polyoxymethylene copolymer used in the present invention is preferably 0.1 to 2.0% by weight, particularly preferably 0.1 to 2.0% by weight in the resin material. 1 to 1.0% by weight.

Slidability improving agent In the present invention, the slidability improving agent blended with the above-mentioned polyacetal resin comprises two components of an acrylic-modified polyorganosiloxane and an unmodified polyorganosiloxane. The acrylic-modified polyorganosiloxane, which is the first slidability improver component, is obtained by graft copolymerizing an acrylic ester and / or a methacrylic ester and, if necessary, a monomer copolymerizable therewith with the polyorganosiloxane. Selected from acrylic-modified polyorganosiloxane
In addition, the kinematic viscosity of the polyorganosiloxane component of the acrylic-modified polyorganosiloxane is 100,000 cSt to 1
Those of 10 million cSt are preferred.

In the present invention, as the acryl-modified polyorganosiloxane, a commercially available product can be used, but an acrylate ester and / or a methacrylate ester and, if necessary, a copolymer thereof are added to an unmodified polyorganosiloxane component. It can also be prepared by graft copolymerization of possible monomers. Specific examples of the acrylate and / or methacrylate include methyl ester, ethyl ester, propyl ester, butyl ester, hexyl ester, octyl ester, lauryl ester of acrylic acid and / or methacrylic acid.
Examples thereof include alkyl esters such as stearyl ester, alkoxyalkyl esters such as methoxyethyl ester and butoxyethyl ester, cycloalkyl esters such as cyclohexyl ester, and aryl esters such as phenyl ester. Specific examples of monomers that can be used as needed, which are copolymerizable with acrylic esters and / or methacrylic esters, include simple monomers such as ethylene, styrene and acrylonitrile. Functional ethylenically unsaturated monomers, acryl and / or methacryl (hereinafter, “(meth) acryl”
Amide group-containing monomers such as amide, N-methylol (meth) acrylamide, etc., glycidyl acrylate and / or methacrylate (hereinafter abbreviated as "(meth) acrylate"), and oxirane group-containing glycidyl allyl ether and the like. Examples include monomers, monomers containing a hydroxy group such as 2-hydroxy (meth) acrylate, and polyfunctional ethylenically unsaturated monomers such as divinylbenzene.

The method of graft copolymerization is not particularly limited. For example, unmodified polyorganosiloxane,
The acrylic acid ester and / or methacrylic acid ester and, if necessary, a monomer copolymerizable therewith may be formed into an aqueous emulsion and polymerized in the presence of a polymerization initiator. The emulsifier and the polymerization initiator used here are also not particularly limited. After the polymerization, an acryl-modified polyorganosiloxane which is a graft copolymer is obtained by salting out, separation, washing with water and drying.

The unmodified polyorganosiloxane, which is the second slidability improving component, has a kinematic viscosity of 100,000 cSt to 10
It is selected from polyorganosiloxanes in the range of 100,000 cSt. Outside this range, the dispersion in the polyacetal resin becomes insufficient, and the effect cannot be obtained or bleed out occurs, which is not preferable.

In the present invention, the unmodified polyorganosiloxane as the second slidability improving component or the unmodified polyorganosiloxane as the raw material of the first slidability improving component may be a commercially available product. Can be used, but
It can also be prepared by polymerization. For example, a cyclic (or linear) oligomer of an organosiloxane obtained by hydrolyzing chlorosilane is subjected to ring-opening polymerization in the presence of an alkali catalyst or the like, and if necessary, a predetermined kinematic viscosity is obtained by appropriately using a terminal stopper. To prepare a polyorganosiloxane having the formula:

Polyacetal Resin Composition In the polyacetal resin composition of the present invention, it is necessary that a predetermined amount of the above two-component slidability improver mixture is blended with a predetermined polyacetal resin. Further, it is preferable that the two-component slidability improving agent is blended in a predetermined ratio. That is, the compounding amount of the mixture of (1) the acrylic-modified polyorganosiloxane and (2) the unmodified polyorganosiloxane is as follows.
The amount is 0.05 to 20 parts by weight, preferably 0.1 to 10 parts by weight, particularly preferably 0.3 to 5 parts by weight based on 00 parts by weight. When the compounding amount is small, the mechanical properties are less likely to decrease and the appearance is good, but the slidability is not sufficiently improved. On the other hand, when the blending amount is large, the slidability becomes good and the squeak noise is reduced, but the mechanical properties and appearance are reduced,
Exceeding 0 parts by weight is not preferred because the mechanical properties are greatly reduced and the appearance deteriorates. The ratio of (1) the acrylic-modified polyorganosiloxane to the (2) unmodified polyorganosiloxane is 85 / (weight ratio of (1) acrylic-modified polyorganosiloxane / (2) unmodified polyorganosiloxane). 15 to 1/99, preferably 5
0 / 50-1 / 99, particularly preferably 35 / 65-1 /
It is preferably 99. This ratio is 85/15 to 1
In the case of 00/0, the improvement of the slidability tends to be insufficient,
When the ratio is 1/99 to 0/100, the appearance of a molded product, for example, a gear, tends to be poor. The flexural modulus of the polyacetal resin composition is not less than 90% of the flexural modulus of the raw polyacetal resin when the mixture of (1) the acrylic-modified polyorganosiloxane and (2) the unmodified polyorganosiloxane is not blended. Is preferred in terms of mechanical strength.

The method for preparing the composition of the present invention is not particularly limited as long as a predetermined amount of the above-mentioned two kinds of the above-mentioned slidability improver components can be blended with a predetermined polyacetal resin.
Any method generally used for preparing a resin composition can be selected. For example, the polyoxymethylene copolymer and the two-slidability improver component, directly or after previously mixing the polyoxymethylene copolymer with each of the slidability improver components,
The mixture is kneaded with a single-screw or twin-screw extruder and pelletized to prepare a polyacetal resin composition. Further, in order to obtain a molded product, a method of molding a pellet prepared to an intended composition is usually performed. If desired, pellets having a different composition are once mixed (diluted) in a predetermined amount and subjected to molding. A method of obtaining a molded article having a desired composition after molding can also be performed. In the preparation of such a pellet material, pulverizing a part or all of the polyoxymethylene copolymer as a substrate is a preferable method for improving the dispersibility of components to be blended therewith.

[0019]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Examples 1 to 10 and Comparative Examples 1 to 6 Polyacetal resin composition 1) Material [Polyacetal resin] Trioxane and a small amount of 1,3-
The mixture with dioxolane (comonomer) is polymerized in the presence of boron trifluoride etherate (catalyst) to give three oxyethylene groups of 0.75% by weight, 1.00% by weight and 1.50% by weight. A copolymer was prepared. After the polymerization, the catalyst was deactivated by triethylamine (deactivator), and pelletized through a terminal stabilization step.

[Slidability improving agent] Two types of acrylic-modified polyorganosiloxane (A) and (B) and two types of unmodified polyorganosiloxane (C) and (D) were prepared. (A) Methyl methacryl-modified polyorganosiloxane (* Kinematic viscosity of polyorganosiloxane component: 6,000,000 c
St) (B) Ethylene methyl methacryl-modified polyorganosiloxane (* kinematic viscosity of polyorganosiloxane component: 6)
(Million cSt) (C) Polyorganosiloxane (Kinematic viscosity: 6,000,000 c
St) (D) Polyorganosiloxane (kinematic viscosity: 10,000 cS)
t)

2) Combination Polyacetal resin 1 having a comonomer content shown in Table 1
To 100 parts by weight, the types and amounts of the sliding agents shown in Table 1 were blended, kneaded with a PCM-30 extruder manufactured by Ikegai Iron Works, and then pelletized, and the polyacetal resin of each of the examples and comparative examples. A composition was obtained.

3) Molding The obtained polyacetal resin composition was injection-molded under ordinary conditions to perform various evaluation tests, and used as test specimens. The specifications of gears molded for evaluation of gear characteristics are as follows:
It was as follows. Gear specifications: module 1.0, number of teeth 50, tooth width 5 mm,
Standard involute tooth profile, spur gear

Evaluation Tests The polyacetal resin compositions and molded products of the respective examples and comparative examples were subjected to evaluation tests of sliding characteristics and gear characteristics, respectively. The test method is as follows. Table 1 shows the evaluation results. 1) Flexural modulus Measured according to ASTM D790. 2) Sliding characteristics Diameter: 25 mm, inner diameter: 20 mm, height: 15 m, based on JIS K 7218, using a Suzuki friction and wear tester
Using a ring-shaped molded product of m, the dynamic friction coefficient and the sliding noise (squeaking noise) were evaluated. Linear velocity: 10 cm / sec, surface pressure:
Each item was evaluated under the condition of 0.49 MPa.

3) Gear Characteristics (Gear Meshing Noise and Breaking Life) [Gear Meshing Noise] The above-mentioned gear molded products are engaged with each other, and the load torque is 0.2 N · m and the rotation speed is 200 r.
pm, 400 rpm, and 800 rpm.
The sound was measured for equivalent noise level using a sound level meter. [Gear breakage life] The gear molded products of the above specifications were engaged with each other, operated at a load torque of 2.0 N · m and a rotation speed of 800 rpm, and the integrated rotation speed at which the teeth were broken and the rotation was no longer transmitted was measured. .

[0026]

[Table 1]

From the evaluation results in Table 1 above, 1) As shown in Comparative Examples 1 to 3, even if the oxymethylene-oxyalkylene copolymer is used without using a sliding agent at all, the friction coefficient is increased. It is not only inevitable that the generation of squeak noise is inevitable, but also in particular, when molded into gears, the meshing noise is large and the break life is short, as apparent from comparison with Examples 1, 4, and 5. 2) As shown in Comparative Example 4, even if a polyorganosiloxane sliding agent was used, a kinematic viscosity of about 10,000 cSt was selected. It is clear from the comparison with Examples 2 and 3 that the breakage life is 1/30 and that the meshing noise tends to increase, especially when molded into 3mm. 3) As shown in Comparative Examples 5 and 6, Full of kinematic viscosity Even in the case of a high-sliding agent, if one of the acrylic-modified polyorganosiloxane and the unmodified polyorganosiloxane is used alone, the coefficient of friction is rather large, as in the case where no sliding agent is used. In addition to the inevitable generation of squeak noise, when formed into a gear, it is clear from the comparison with Example 1 that the meshing noise is large and the break life is short. 4) On the other hand, in Examples 1 to 10, the use of a mixture of the two-component slidability improver in various amounts, components, and ratios prevents the occurrence of squeak noise, and is used as a gear. In addition, the mesh noise has been reduced, and the break life has been extended.

[0028]

The resin composition of the present invention has high strength and excellent sliding properties as compared with the conventional polyacetal resin, and provides a molded article having an excellent appearance, particularly having very little sliding noise such as squeaking noise. Can be. Since the resin composition of the present invention has the above-mentioned excellent characteristics, it is suitable for resin gears, mechanical parts, and the like.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Susumu Matsumoto 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa F-term in Technical Center, Mitsubishi Engineering-Plastics Co., Ltd. 4F071 AA33X AA40 AA67 AA67X AA77 AA88 AF20 AF28 BA01 BB05 BC03 4J002 BN17X CB00W CP03Y GC00 GL00 GM00 GN00 GQ00

Claims (6)

[Claims] 1. An acrylic ester and / or (1) polyorganosiloxane, based on 100 parts by weight of a polyoxymethylene copolymer having an oxymethylene group as a main repeating unit and having an oxyalkylene group having 2 or more carbon atoms. Methacrylic acid ester and, if necessary, an acrylic-modified polyorganosiloxane obtained by graft copolymerizing a monomer copolymerizable therewith, and (2) a kinematic viscosity of 100,000 cSt
A polyacetal resin composition comprising 0.05 to 20 parts by weight of a mixture of an unmodified polyorganosiloxane having a content of 10,000,000 cSt or less. 2. The weight ratio of (1) acrylic-modified polyorganosiloxane / (2) unmodified polyorganosiloxane is as follows:
The ratio is from 85/15 to 1/99.
3. The polyacetal resin composition according to item 1. 3. The kinematic viscosity of the polyorganosiloxane component of the acrylic-modified polyorganosiloxane is 100,000 cSt.
The polyacetal resin composition according to claim 1, wherein the composition is not less than 10,000,000 cSt. 4. The polyoxymethylene copolymer has 2 carbon atoms.
The polyacetal resin composition according to any one of claims 1 to 3, comprising 0.5 to 3.0% by weight of the above oxyalkylene group. 5. The resin composition according to claim 1, wherein the flexural modulus of the resin composition is 90% or more of the case where no acrylic-modified polyorganosiloxane and unmodified polyorganosiloxane are added. 3. The polyacetal resin composition according to item 1. 6. A molded article obtained by molding the polyacetal resin composition according to any one of claims 1 to 5.