JPS60127346A - Acetal resin composition - Google Patents

Abstract

PURPOSE:The titled composition, obtained by incorporating an acetal resin with a fibrous reduced potassium titanate, a polycarbonate compound, an amine- substituted triazine compound and a cyanoguanidine compound, and having improved antistatic property, electric conductivity and impact and heat resistance. CONSTITUTION:An acetal resin composition obtained by incorporating an acetal resin with a fibrous reduced potassium titanate, a low-molecular weight polycarbonate compound having <=0.3dl/g intrinsic viscosity in methylene chloride at 25 deg.C and an amino-substituted triazine compound and/or a cyanoguanidine compound. The above-mentioned potassium titanate to be used has <=2mum average fiber diameter and 5-100mum average fiber length at >=10 aspect ratio. A polycarbonate compound, derived from 2,2'-bis(4-hydroxyphenyl)propane, and having terminals blocked with phenol, etc. is used as the polycarbonate compound.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acetal resin composition that has excellent antistatic ability and conductivity, and provides a molding material with excellent impact resistance, heat resistance, etc.

Due to its excellent mechanical strength, hardness, sliding properties, heat resistance, chemical resistance, and fatigue resistance, acetal resin is used for internal structural parts such as gears, bearings, cams, sleeves, and shafts. It is used. However, when used as a sliding part, there are problems due to the generation of static electricity due to friction, and especially when used as an electrical part, it causes problems such as the adhesion of flakes and the generation of electrical noise.

Conventionally, one method for imparting antistatic properties to acetal resins is to use compounds with hydrophilic groups such as polyhydric alfurs, fatty acid esters of polyhydric alcohols, polyalkylene glycols, polyoxyalkylene-substituted triazines, and alkylamine compounds. There is a way to add. However, this method has the drawback that the surface resistivity of the acetal resin molded product can only be reduced to about 10''Ω at most, and the resistance value changes significantly depending on humidity.Another method is to use conductive carbon black. There is a method of blending carbon black into acetal resin, but carbon black causes a significant deterioration of the thermal stability of acetal resin, has a small bulk specific gravity, and is extremely difficult to handle when compounding, and is also susceptible to thermal decomposition during molding. , silver streaks occur in the resulting molded product, and the mold is contaminated.Also, there are many drawbacks such as a significant drop in impact strength.Also, there is a method of blending carbon fiber, but carbon fiber is Currently, it is expensive and is not used for anything other than special purposes.

In view of the above circumstances, the inventors of the present invention have developed a method for applying acetal resin. As a result of extensive research in order to obtain an acetal resin molding material that has preventive properties and conductivity, as well as excellent impact resistance and heat resistance, we found that by adding fibrous reduced potassium titanate, we could improve the excellent properties of 7-cetal resin. It has been found that antistatic properties and conductivity can be imparted without sacrificing performance, leading to the present invention.

That is, the present invention uses an acetal resin containing fibrous reduced potassium titanate, which has an intrinsic viscosity of 0 at 25°C in methylene chloride.
, 5 d4/g or less and a low molecular weight polycarbonate compound and an amine-substituted triazine compound and/or a cyanoguanidine compound.

The fibrous reduced potassium titanate (hereinafter referred to as reduced PTW) used in the present invention is a single crystal fiber having a composition represented by the following general formula (υ), with an average fiber diameter of 2 μm or less and an average fiber length of 5 to 100 μm. and the average fiber length/average fiber diameter (7 spectral ratio) is 10 or more.

KzO・n(Ti02- x) <1) (wherein, n is 2
An integer of ~8, X represents a real number of 2 or less. ) This reduced PTW is produced by mixing potassium titanate whiskers with a composition of KzO・n(Ti02) (in the formula, n represents an integer from 2 to B) with a carbon material, and then reducing or inactivating the mixture under a surrounding atmosphere. Obtained by heat treatment at 500 to 1500°C.

Examples of the carbon material used here include carbon black, graphite, pukes, petroleum pitch, and the like. In addition, the mixing ratio of potassium titanate whiskers and carbon material depends on the size and material of the reduction furnace, or the desired reduction PT.
Depending on the conductivity of W, the carbon material is typically 1 to 50% by weight relative to the potassium titanate whiskers.

Compared to conductive carbon black, this reduced PTW has extremely high dispersibility when blended with acetal resin. However, by relatively gentle kneading, it is possible to easily and sufficiently disperse the components.

Furthermore, in the present invention, a low molecular weight polycarbonate compound and an amine-substituted triazine compound and/or a cyanoguanidine compound having an intrinsic viscosity of 0.5 d4/g or less at 25° C. in methylene chloride are added.

These additives have the effect of improving wetting between the acetal resin and reduced PTW, increasing the interfacial adhesive strength, increasing mechanical strength, and increasing heat resistance.

The low molecular weight polycarbonate compound used in the present invention generally has a melting point of 240°C or lower, and melts at a temperature of 180 to 240°C, which is the molding temperature of a normal 7-cetal resin. This is an important property in increasing the adhesive strength between the reduced PTW and the acetal resin, and in increasing the mechanical strength and heat resistance of the molded product. The low molecular weight polycarbonate compound has an intrinsic viscosity of 0.56137 g or less at 25° C. in methylene chloride.

The low molecular weight polycarbonate compound has the following general formula (
1) (In the formula, R1-R8 are each hydrogen, an alkyl group,...al
l group, substituted furkyl group, alkoxy group, X has 1 carbon number
~10 alkyl groups, substituted alkyl groups, acids, sulfur
502) or is a polycarbonate compound derived from a dihydric phenol represented by the formula is a furkyl group having 1 to 10 carbon atoms, a substituted furkyl group, oxygen, sulfur, SO2), or is a polycarbonate compound derived from an alicyclic hydrocarbon having two hydroxyl groups in the molecule, or is a polycarbonate compound derived from an alicyclic hydrocarbon having two hydroxyl groups in the molecule; )
(It is a polycarbonate compound derived from a mixture of 23.

Specifically, 2.2'-bis(4-hydroxyphenyl)furopane, 2.2'-bis(4-human+--1-cy5.5-dibromphenyl)furopane, 2.2'- Bis(4-hydroxyphenyl)butane, 2,2'-bis(
6-bromo-4-hydroxyphenyl)propane, 2.
"Aromatic dihydric phenols and , 2.2'-bis(4-humanoxycyclohexyl)propane, 2.2'-bis(4-hydroxy-5.
5-dibromocyclohexyl)propane, 2.2'-bis(4-hydroxy-3.5-dimethylcyclohexyl)propane, 21τ-bis(4-hydroxycyclohexyl)butane, 4.4'-dihydroxydicyclohexyl ether, 4. Examples include alicyclic hydrocarbons having two hydroxyl groups on each side, such as 4'-dihydroxydicyclohexyl sulfone and 4,4'-dihydroxydicyclohexyl sulfide.

Another specific example is 1,3-propanediol, 1.
Examples include chain-axe hydrocarbons having two hydroxyl groups such as 4-butanediol and 1,6-hexanediol.

Polycarbonate compounds are synthesized by reacting these compounds with phosgene or carbonic diester.

For the reaction, an interfacial polymerization method using phosgene and a transesterification method with a carbonic acid diester can be adopted according to a known method.

Among the polycarbonated metal products used in the present invention, 2,2'-bis(4-hydroxif22k)
A polycarbonate compound derived from pan and whose terminal end is capped with phenol and/or furkyl-substituted phenol, a polycarbonate derived from 2,2'-bis(4-hydroxy 5,5 sif'a muphenyl)furopane. 2,21-bis(4
Preferred are polycarbonated metals derived from -hydroxyschiff-hexyl)propane.

The amine-substituted triazine used in the present invention is represented by the formula (3) (where R1, R2 and Rs are a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an alkoxy group, an aryl group, a hydrogenated aryl group, an amino group or a methylol group). (meaning an amino group, at least one of which is an ami7 group or a methyl p-ylamino group). Specifically, guanamine (
2,4-diamino-83τm-) lyazine), melamine (2,4.6-)su7mino-sym-) lyazine),
N-butylmelamine, N-phenylmelamine, N,N-
diphenylmelamine, N, N-diallylmelamine, N,
M,N'-)liphenylmelamine, N-monomethylolmelamine, N,N-dimethylol 1547, N,N,N
'-trimethylolmelamine, benzoguanamine (2,
4-diamino-6-phenylene (sym-triazine)
, 2,4-diamino-6-methyl-sym-) riazine, 2,4-diamino-6-butyl-sym-) riazine, 2,4-diamino-6-benzyloxy-sym -
) riazine, 2,4-dioxy-6-amino-sym-
)Ryazine (Ameride), 2-oxy-4,6-diamitsusym-)Ryazine (7Melin), N.

Examples include N,N,N-tetracy7noethylbenzoguanamizo and the like. Among them, melamine, guanamine, benzoguanamine, N-monomethylolmelamine, N
, If-dimethylolmelamine, N,N,N'-)dimethylolmelamine can be particularly preferably used.

Furthermore, the cyanoguanidine compound used in the present invention is a compound represented by formula (4) (wherein Rt and R2 are a hydrogen atom, an alkyl group ζ-substituted alkyl group, an alkoxy group, or a substituted alkoxy group). , specifically, cyanoguanidine itself, 1-cyano-5-methylguanidine, 1
-Cyano-6-nitylguanidine, 1-cyano-3-isopropylguanidine, 1-cyano6,6-dipheny!
Examples include leganidine, 1-cyano-3-oxymethylguanidine, 1-cyano-5-(2-oxyethyl)guanidine, and the like. Cyanoguanidine is most preferred because it is easily available.

The blending ratio of each component constituting the resin composition of the present invention is generally 7 cetal resin 58 to 96 parts by weight 9 opposing parts reduced P
TW 5 to 40 parts by weight, low molecular weight polycarbonate compound 0.1 to 5 parts by weight, and amine-substituted triazine compound and/or cyanoguanidine compound 0.01 to 5 parts by weight. Reduced P is used to increase the conductivity of molded products.
It is preferable to use a large amount of TW within the above range; for example, in order to reduce the surface resistivity to 10 Ω or less, it is preferable to add 15 parts by weight or more of reduced PTW;
To make the surface resistivity value 101 to 10-10, reduce P
It is preferable to add about 25 parts by weight or more of TW.

However, if the amount of reduced PTW exceeds 40 parts by weight, the fluidity during molding will decrease and jetting, flow marks, etc. may occur, which is undesirable.

Furthermore, the amount of the low molecular weight polycarbonate compound, amine-substituted triazine compound and/or cyanoguanidine compound can be varied within the above range depending on the blending amount of the reduced PTW. Generally, as the amount of reduced PTW increases, a correspondingly large amount is used.

The acetal resin used in the resin composition of the present invention is
An oxymethylene homopolymer consisting essentially only of oxymethylene units produced from formaldehyde monomer or a cyclic oligomer such as its hexamer (trioxane) or its tetramer (tetraoxane), and the above raw materials, ethylene oxide, and propylene. oxide,
Epichlorohydrin, 1,6-dioxolane, 116-
Includes an oxymethylene fuborimer consisting of an oxymethylene unit produced from a cyclic ether such as sioxeban, formal of glycol, formal of diglycol, etc. and an oxyalkylene unit of 02 or more.

The resin composition of the present invention may further contain heat stabilizers, light stabilizers, antioxidants, and lubricants that are known per se, as necessary and within a range that does not impair the effects of the present invention. be.

The most common method for producing the 7-cetal resin composition of the present invention is to tri-blend all the components and extrude and knead them at once.
It is also possible to adopt a method in which two or three components are mixed in advance and then melt-kneaded with the remaining components. In particular, one preferred embodiment is to melt-knead the polyacetal resin with the low molecular weight polycarbonate compound and/or amine-substituted triazine compound and/or cyanoguanisine compound according to the present invention, and then supply reduced PTW thereto.

As a device for melt-kneading, it is preferable to use a single-screw extruder for thorough kneading, but in some cases, a twin-screw extruder rotating in the same direction or in different directions may also be used. As other devices, batch-type kneaders such as a kneader, Banbury mixer, and mixing rule can also be used.

Next, the content of the present invention will be specifically explained using Examples and Comparative Examples.

Reference example (manufacture of reduced PTW) Potassium titanate whisker (Tismop manufactured by Otsuka Chemical ■) represented by KzO-n(Ti02) (in the formula, n has a distribution of 4 to 8 and is 6 on average) 10 9 and carbon black 1 were mixed and placed in an electric furnace made of high-purity alumina, and the inside of the furnace was purged with nitrogen gas. The inside of the furnace was heated, and after reaching 1200°C, it was held for 20 minutes. While maintaining the nitrogen atmosphere inside the furnace, cool it to room temperature and reduce the reduced P.
I took out TW. This one is K26・n (Ti02
-x) In formula C, n has a distribution of 4 to 8 and has an average of 6. X is 0.01 to 1.0), and this material is placed in a hard lath cell with an inner diameter of 0.4 cIL, and then pressed with a stainless steel push rod of 0.696 in outer diameter.
6 and measured the resistance value between the upper and lower surfaces using a tester, the specific resistance value was 1×10 Ωα.

Example 1 7-cetal copolymer with an Ml value of 27.5 containing 2.8% by weight of fumonomer units derived from ethylene oxide (Evital F2O-01 manufactured by Mitsubishi Gas Chemical Co., Ltd.)
The pellets were heated at 25°C with a polycarbonate compound containing the reduced PTW obtained in the reference example and bisphefur A as starting materials.
Intrinsic viscosity in methylene chloride is o, 15 d137
A low molecular weight polycarbonate compound with a g-average degree of polymerization of 7 and melamine were triblended in the proportions shown in Table 1. This mixture was heated and kneaded using a 50 m/m diameter full-flight screw single screw extruder 111 (L/D=50 with a vent) at a resin temperature of 220''G to pelletize.

The resin composition thus obtained was injection molded at a resin temperature of 205° C. and an injection pressure of 800 to a thickness of 5 mm and 2 ms 1.
134 cm square plate and tensile impact test piece (thickness 1.6
aI S type) and a tensile test piece (thickness !1.2. dumbbell type) were obtained. The electrical properties and mechanical strength of these molded products were measured.

Comparative Example 1 was produced in the same manner without using the low molecular weight polycarbonate compound produced by the present invention.

Their compositions and physical properties are shown in Table 1.

Table 1 In the table, the formulation composition is expressed in parts by weight, with the total composition being 100.

Example 2 and Comparative Example 2 Reduced PTW produced in Reference Example was added to Tenac 7010 pellets manufactured by Asahi Kasei Corporation, which is an acetal homopolymer.
and 2,2'-bis(4-hydroxycyclohexyl)
Intrinsic viscosity in methylene chloride at 25°C of a polycarbonate compound prepared from fluoropane: 0, 10 d
A low molecular weight polycarbonate compound having an i1g number average degree of polymerization of 9 and cyanoguanidine were triblended in the proportions shown in Table 2 and melt kneaded in the same manner as in Example 1 to obtain a molding material.

As a comparative example, conductive carbon black (AK Z
Ketjenblack E, C) manufactured by Company O and low density polyethylene were mixed and extruded in the same manner. The blending ratios and physical properties of these compositions are shown in Table 2.

Table 2 shows that the conductive resin composition of the present invention has excellent conductivity and high impact strength.

Note that even if a normal twin-screw extruder is used, the acetal resin
It is difficult to melt and knead Ketjen black in an amount of 0 parts by weight or more, and in a single screw extruder, it is practical to mix Ketjen black in an amount of at most 5 parts by weight or less.

Table-2

Claims (1)

[Claims] An acetal obtained by adding fibrous reduced potassium titanate, a low molecular weight polycarbonate compound with an intrinsic viscosity of 0.5 d4/g or less in methylene chloride at 25°C, and an amine-substituted triazine compound and/or a cyanoguanidine compound to an acetal resin. resin composition