JPS63210161A - Polyoxymethylene resin composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. which has excellent thermal stability and mechanical properties and is antistatic, by blending a polyoxymethylene resin with specified electrically conductive carbon black and an epoxy compd. CONSTITUTION:A polyoxymethylene resin (A) is blended with 0.5-30wt.% electrically conductive carbon black (B) having a dibutyl phthalate absorption of 200ml/100g or higher, 0.05-10wt.% epoxy compd. (C) (pref. a mono- or polyfunctional glycidyl derivative) and optionally, 0.1-10wt.% additive (D) for curing said epoxy compd., selected from the group consisting of substd. imidazole compds. of formula I [wherein R1 is a (substd.) alkyl, an aryl, allyl or vinyl; R2, R3 and R4 are each H or R1], tert. amine compds. of formula II [wherein R5 is a (substd.) 3C or higher alkyl or an aryl; R6 and R7 are each a (substd.) alkyl or an aryl], morpholine compds. of formula III (wherein R8 is R5) and dicyandiamide derivatives of formula IV [wherein R9 is a residue of a random or block copolymer of formula V (wherein x+y=1-20, x=0-20, y=0-20)].

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to novel polyoxymethylene compositions. More specifically, the present invention relates to an antistatic polyoxymethylene composition having extremely excellent thermal stability and mechanical properties.

BACKGROUND OF THE INVENTION Polyoxymethylene resins have excellent mechanical strength, creep properties, lubricating properties, and electrical properties, and are therefore widely used in, for example, automobile parts, electronic/electrical equipment parts, and audio equipment parts. However, when used as a sliding member, there are often problems in use due to the generation of static electricity due to friction, so a desired amount of carbon black is added to the material. However, simply adding carbon black to polyoxymethylene resin inevitably leads to a decrease in thermal stability, fluidity, and mechanical properties, making it impossible to obtain a fully satisfactory polyoxymethylene resin composition. The problem arises.

In order to solve this problem, an attempt has been made to add low density polyethylene together with conductive carbon black (Japanese Patent Application Laid-open No. 111348/1983), but this method requires a large amount of low density polyethylene. If it is not added, sufficient effects cannot be obtained, which has the disadvantage that the inherent mechanical properties of the polyoxymethylene resin are greatly impaired. It has also been proposed to add an ethylene oxide adduct of amidated τ together with conductive carbon black (Japanese Patent Publication No. 31736/1983), but this method does not provide a sufficiently satisfactory effect.

Problems to be Solved by the Invention Under these circumstances, the present invention provides a polyoxymethylene resin composition that has antistatic properties and also has good thermal stability and mechanical properties. It was done for the purpose of

Means for Solving the Problems The present inventors have conducted intensive research to develop a polyoxymethylene resin composition having the above-mentioned excellent characteristics. By adding an epoxy compound and, if desired, an epoxy resin curing additive to a methylene resin in a predetermined ratio,
We have found a way to achieve this objective, and based on this knowledge, we have completed the present invention.

That is, the present invention provides (A) a polyoxymethylene resin,
(B) Dibutyl phthalate oil absorption 200 mA71009
It consists of the above conductive carbon black, (C) an epoxy compound, and optionally (D) an epoxy resin curable additive, and the component (B) is 0.5 to 0.5% based on the total composition weight.
30% by weight, component (C) (0.05-105-10% by weight) is in the range of 0.1-10% by weight. be.

The polyoxymethylene resin used as component (A) in the present invention may be any commonly used polyoxymethylene and is not particularly limited.

In addition, the conductive carbon black to be blended as component (B) is preferably one with a small particle size or a large surface area and a developed chain structure, but dibutyl heptalate (hereinafter abbreviated as DBP) is an oil-absorbing carbon black. The amount is 200 mA/100
It is necessary that the value be greater than or equal to f. This DBP oil absorption is a measure of the degree of development of carbon black stractures, and as the stractures develop,
．． -a The higher the DBP oil absorption, the higher the electrical conductivity. The DBP oil absorption (ml/100 f) can be determined by titrating a certain amount of carbon black stirred in a kneader mixer with DBP using an automatic burette.

In this titration, the powder that was freely flowing when the DBP of carbon black is at its maximum (filling of voids) changes to semi-plastic properties, and the torque of the kneader increases rapidly. Required DBP amount per hit (
-) is DBP oil absorption, ASTM D 2415-
It is recognized as a stracture index of 65T.

Like this, the BP oil absorption amount is 200ff17!7100
Carbon black with a carbon black of less than A significant decrease in physical properties is inevitable.

In the composition of the present invention, examples of conductive carbon black that can be used include Toka Black $4500 [
Oil absorption amount i 230d/100, manufactured by Tokai Carbon ■],
#3750 [Oil absorption; 245 td/100 f
.

Made by Mitsubishi Kasei ■], Ketjen Black EC [Oil absorption i
350 rnl/100 f, manufactured by Lion Axie]
, Ketjenblack EOD, T-600 [I oil absorption: 480rd/1009, manufactured by Lion Axie], Purinki Tsux xwzc oil absorption: 370 d/100
F, manufactured by Degussa), but is not particularly limited to these.

The amount of these conductive carbon blacks must be selected in the range of 0.5 to 30% by weight based on the weight of the composition, and if this amount is less than 0.5% by weight, the antistatic ability will not be fully exhibited. On the other hand, if it exceeds 30% by weight, the impact resistance will be significantly reduced. The preferred amount is selected within the range of 2 to 20% by weight.

In the composition of the present invention, the epoxy compound blended as component (C) is preferably a mono- or polyfunctional glycidyl derivative, such as 2-ethylhexyl glycidyl ether, 2-methyloctyl glycidyl ether, lauryl Glycidyl ether, stearyl glycidyl ether, behenyl glycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether (units of ethylene oxide; 2 to 30), 7'lopylene glycol diglycidyl ether, polypropylene glycol 8 to diglycidyl ether (Units of propylene oxide; 2 to 30),, i, Opentyl glycol diglycidyl ether, 1,6-hexanesiol diglycidyl ether, Glycerin diglycidyl ether, Glycerin triglycidyl ether, Trimethylolpropane diglycidyl ether, Methylolpropane triglycidyl ether, bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether,
Sorbitan monoester diglycidyl ether, sorbitan monoester triglycidyl ether, pentaerythritol triglycidyl ether, pentaerythritol tetraglycidyl ether, diglycerin triglycidyl ether, diglycerin tetraglycidyl ether, cresol novo, condensate of lac and epichlorohydrin (epoxy Equivalent weight: 100-400, Softening point: 20
~150°C), but is not particularly limited thereto.

These epoxy compounds may be used alone or in combination of two or more, and the blending amount is from 0.05 to 0.0% by weight, preferably 0.05% by weight, based on the weight of the composition. .5 to 7% by weight. If this amount is less than 0.05 weight ratio, the effect as a thermal stabilizer will hardly be exhibited, while if it exceeds 10 weight ratio, the mechanical properties will be significantly reduced. The optimum blending amount is appropriately selected depending on the type and amount of conductive carbon black used.

In the composition of the present invention, if desired, further components (or components) may be used.
As the epoxy resin curing additive, a commonly used epoxy resin curing agent or a substance that accelerates the curing of epoxy resin can be used.

As the former epoxy resin curing agent, aliphatic and modified polyamines, modified aromatic amines, acids and acid anhydrides are mainly used. Examples of these epoxy resin curing agents include diethylenetriamine (DTA), triethylenetetramine (TTA), diethylaminopropylamine (DEPA), N-aminoethylpiperazine (N-A
RP), benzyldimethylamine (BDMA), metaphenylenediamine/(MPD), diaminodiphenylmethane (DDM), diaminodiphenylsulfone (DD
S), dicyandiamide, boron trifluoride monoethylamine (BF3・MEA), menthanediamine, xylylene diamine, bisaminopropyltetraoxaspiroundecane adduct (EATUA), imidazole, 2-ethyl-4-methylimidazole (KM Engineering) ), phthalic anhydride (FA), maleic anhydride (MA), dodecylsuccinic anhydride (DDSA), hexahydrophthalic anhydride (HHPA), methylnadic anhydride (MNA)
, pyromellitic anhydride (PMDA), benzophenonetetracarboxylic anhydride (BTDA), etc.
It is not particularly limited to these. These curing agents may be used alone or in combination of two or more.

On the other hand, substances that accelerate the curing of epoxy resins include, for example, the general formula (wherein R1 is an alkyl group, an aryl group, an allyl group, or a vinyl group, with or without a substituent, R2, R
3 and R4 are each a hydrogen atom, or an alkyl group, an aryl group, an allyl group, or a vinyl group with or without a substituent, and they may be the same or different.) A substituted imidazole compound represented by the general formula (wherein R5 is an alkyl group or aryl group having 8 or more carbon atoms with or without a substituent, R6 and R7 are an alkyl group or an aryl group with or without a substituent, respectively) A tertiary amine compound represented by the general formula (R8 in the formula may be the same or different)
is an alkyl group or aryl group having 8 or more carbon atoms, with or without a substituent), and a morpholine compound represented by the general formula [in the formula, R9, R10, R11 and R12 are each ÷02H40+-+03HBO-]
-H---(V)
dicyandiamide, which is a residue of a random copolymer or a block copolymer represented by (a number that satisfies the relationship of 0), which may be the same or different from each other. Examples include derivatives.

In these compounds, R1, R2, R3, R4, R
When 6 and R7 are alkyl groups, the number of carbon atoms is preferably in the range of 1 to 30, and R5 and R
When 8 is an alkyl group, the number of carbon atoms is 8 to 30
Preferably, it falls within this range.

Examples of the substituted imidazole compound represented by the general formula (I) include 1-hydroxyethyl-2-methylimidazole, 1-cyanoethyl-2-heptadecyl imidazole, 1-vinyl-2-phenylimidazole, 1
-Lauryl-2-undecyl imidazole, 1-allyl-2-inzolobyl imitasol, 1-benzyl-2-
Ethylimidazole 1-stearyl, -2-methyl-4-ethylimidazole, 1-ethyl-5-laurylimidazole, 1-phenyl-4-ethylimidazole, 1-tolyl-2-heptadecylimidazole, 1-triphenylmethyl Examples include, but are not limited to, imidazole, 1-(behenylbenzyl)-2-methylimidazole, 2-(behenylbenzyl)imidazole, 4-(behenylbenzyl)imidazole, 5-(behenylbenzyl)imidazole, etc. There isn't.

Examples of the tertiary amine compound represented by the general formula (It) include octyldimethylamine, octyldiethylamine, dioctylmethylamine, trioctylamine, stearyldimethylamine, stearyldiethylamine, distearylmethylamine, distearylpropylamine, Tristearylamine, behenylstearylmethylamine, behenyldimethylamine, behenyldiethylamine, dioctylmethylamine, sibehenylisozorobylamine, tribehenylamine, trilaurylamine, octyldihydroxydiethylamine, benzyldimethylamine, benzyldibutylamine, benzylstearylmethyl Amine, p-octylphenyldimethylamine, trisdimethylaminobenzene, trisdimethylaminophenol, trisdimethylaminotoluene,
Examples include, but are not limited to, tris(dimethylaminomethyl)phenol, triphenylamine, tritolylamine, diphenyltolylamine, (behenylbenzyl)dimethylamine, and cy(behenylbenzyl)methylamine.

Examples of the morpholine compound represented by the general formula @) include octylmorpholine, laurylmorpholine, cetylmorpholine, stearylmorpholine, behenylmorpholine, phenylmorpholine, p-laurylphenylmorpholine, tolylmorpholine, benzylmorpholine, p-
Examples include, but are not limited to, -methylbenzylmorpholine and behenylbenzylmorpholine.

The dicyandiamide derivative represented by the general formula (goods) is obtained by adding ethylene oxide or propylene oxide or both to dicyandiamide,
These include, for example, 4 molar EO adduct to dicyandiamide, 4 molar PO adduct to dicyandiamide, 10 molar EO adduct to dicyandiamide, 10 molar PO adduct to dicyandiamide, 20 molar PO adduct to dicyandiamide, Mol KO adduct, 20 to dicyandiamide
Molar PO adduct, 40 molar FiO to dicyandiamide
adduct, 40 molar PO adduct to dicyandiamide, 60 molar KO adduct to dicyandiamide, 60 molar PO adduct to dicyandiamide, 8 to dicyandiamide
0 mol FiO adduct, 80 mol K to dicyandiamide
O adduct, 4 mol KO and 7 mol P to dicyandiamide
O copolymerization adduct, 4 mol EO.2 to dicyandiamide
0 mol Po copolymerization adduct, 4 mol EO/40 mol Po copolymerization adduct to dicyandiamide, 4 mol E0/60 mol Po copolymerization adduct to dicyandiamide, 4 mol EO/70 mol Po copolymerization adduct to dicyandiamide Adduct, 10 mol EO/7 mol PO copolymer adduct to dicyandiamide, 10 mol EO/20 mol P to dicyandiamide
o copolymerization adduct, 10 mol Fi0 to dicyandiamide
・30 mol Po copolymer adduct (However, 1 mol or more of KO or PO is added to all four active hydrogens of dicyandiamide, and KO added to one active hydrogen)
, one in which the total number of moles of PO added does not exceed 20 moles), but is not particularly limited to these.

These epoxy resin curing accelerators may be used alone or in combination of two or more.

Furthermore, in the present invention, the above-mentioned epoxy resin curing agent 1
It is also possible to use one or more types of epoxy resin curing accelerator together with one or more types of epoxy resin curing accelerator.

In the composition of the present invention, the amount of the epoxy resin curable additive blended as component (D) is 0.1 to 10% by weight, preferably 0.5 to 7% by weight, based on the weight of the composition. selected. This amount is 0. If the Li content is less than 10%, the effect of the epoxy compound as a heat stabilizer cannot be sufficiently improved, while if it exceeds 10% by weight, the mechanical properties will be significantly reduced. The optimal blending amount of this component (D) is appropriately selected depending on the type and amount of the conductive carbon black and epoxy compound used.

The polyoxymethylene resin in the composition of the present invention may be a polyoxymethylene homopolymer or a polyoxymethylene copolymer or terpolymer consisting mostly of oxymethylene chains, such as formaldehyde or a cyclic oligomer of formaldehyde such as trioxane or tetraxane. Polymers obtained by polymerizing or copolymerizing them alone or with comonomers that can be copolymerized with them are stabilized against decomposition from the terminal, and stabilizers and antioxidants are usually added. is used.

The composition of the present invention can be prepared by melt-kneading each component using a known device, such as a kneader, roll mill, or extrusion machine, which is commonly used for mixing resin melts.

As a melt-kneading device, an extruder is most suitable from the viewpoints of blocking oxygen and working environment. Types of extruders include single-screw, twin-screw, vented, non-vented, and the like, and the composition of the present invention can be prepared using any of these extruders. The mixing temperature must be higher than the melting point of the polyoxymethylene resin used, and sufficient extrusion is possible at temperatures within the usual range of 180 to 230°C. The time required for kneading is approximately the same as the time required for extruding the polyoxymethylene resin alone.

The kneading conditions for preparing the composition of the present invention have been shown above, but the kneading method and conditions are not limited to the above, and may be any known method or method used to prepare a polyoxymethylene composition. Any conditions can be used.

The composition of the present invention may optionally contain various additives commonly used in ordinary polyoxymethylene compositions, such as pigments,
Fillers, lubricants, etc. can be added.

Effects of the Invention The polyoxymethylene composition of the present invention includes a polyoxymethylene resin containing an epoxy compound together with conductive carbon black, or an epoxy compound and an epoxy resin curing agent or curing accelerator together with conductive carbon black. This is a composition that retains the antistatic properties of conductive carbon black, greatly improves the decrease in thermal stability of polyoxymethylene resin caused by conductive carbon black, and maintains the mechanical properties of polyoxymethylene resin. .

The epoxy resin curable additive used in the composition of the present invention has the effect of enhancing the effect of the epoxy compound added as component (C) as a heat stabilizer. Combinations of only resin curing agents and curing accelerators do not exhibit much of the effect of their addition.

Further, the effects of the present invention are particularly greatly exhibited when a substance that accelerates the curing of the epoxy resin represented by the general formulas (I) to (B) is blended.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

In addition, each characteristic of the composition was determined as follows.

(1) Injection molding machine with ST value cylinder temperature 230℃ [ArburgA
12X3X by retaining the resin composition in a llrounder 100 manufactured by Western Trading ■
When molding a molded piece of 12011, 2 on the surface of the molded piece
The critical residence time (minutes) at which silver streaks occur at 1/3 was defined as the ET value.

(2) Ra value The weight residual rate (%) when the composition was heated in air at 230° C. for 120 minutes was taken as the Ra value.

(3) The surface electrical resistance composition was molded using the injection molding machine to a size of 130 x 110 x 3.
rsm molded piece, and measured using the molded piece and an insulation resistance measurement sample box TR-42 (manufactured by Takeda Riken).

Examples 1 to 36 Polyoxymethylene copolymer [Tenac-07510
(Melt index 30 r/10 minutes); Asahi Kasei ■Registered trademark] The pulverized product, conductive carbon black, epoxy compound, and epoxy resin curing additive were mixed using a Henschel mixer in the proportions shown in Tables 1 to 9. After blending, the mixture was kneaded into pellets using a 30mm diameter twin-screw extruder with a cylinder temperature set at 190° C. and a screw rotation speed of 15 rpm. The EIT value and Ra value of this pellet were measured, and a test piece was molded using a molding machine, and its flexural modulus and surface electrical resistance were measured. The results are shown in Tables 1 to 9.

Comparative Examples 1 to 9 Polyoxymethylene resin [Tenatsuku C! 7510(
copolymer, melt index 30f710min), or Tenac 7010 (homopolymer, melt index 309710min); non-chemical registered trademark] crushed product, conductive carbon black, stearic acid jetanolamide, low density polyethylene, epoxy compound, epoxy resin After mixing the curable additives in the proportions shown in Tables 10 and 11 using a Henschel mixer, the cylinder temperature was
i The mixture was kneaded and pelletized using a 30 g 1φ twin-screw extruder set at 190° C. at a screw rotation speed of 15 Orpm. The ST value and Ra value (described above) of this pellet were measured, and a test piece was molded using a molding machine, and its flexural modulus and surface electrical resistance were measured. The results are shown in Tables 10 and 11.

Examples 37-48 Polyoxymethylene homopolymer [Tenac 7010 (
Melt index 30 r/10 minutes); Non-chemical registered trademark] Pulverized product, conductive carbon black, epoxy compound, epoxy resin curing additive, mixed using a Henschel mixer at the compounding ratios shown in Tables 12 to 14. The mixture was kneaded and pelletized using a 30 mmφ twin-screw extruder with a cylinder temperature of 190° C. and a screw rotation speed of 15 rpm. ST value and Ra value (above) of this pellet
f, the bending elastic modulus was measured and the entire test piece was molded using a molding machine;
Surface electrical resistance was measured. The results are shown in Tables 12-14.

Claims (1)

[Scope of Claims] 1 Consisting of (A) polyoxymethylene resin, (B) conductive carbon black with dibutyl phthalate oil absorption of 200 ml/100 g or more, and (C) epoxy compound, and based on the total composition weight, the components (B) is 0.5 to 30% by weight
, an antistatic polyoxymethylene resin composition characterized in that component (C) is in the range of 0.05 to 10% by weight. 2 Consisting of (A) polyoxymethylene resin, (B) conductive carbon black with dibutyl phthalate oil absorption of 200 ml/100 g or more, (C) epoxy compound, and (D) epoxy resin curing additive, and total composition weight Based on the formula, component (B) is 0.5 to 30% by weight and component (C) is 0.5% to 30% by weight.
An antistatic polyoxymethylene resin composition characterized in that the content of component (D) is within the range of 0.05 to 10% by weight and 0.1 to 10% by weight. 3 The epoxy resin curing additive has a general formula ▲ mathematical formula, chemical formula, table, etc.
, R_3 and R_4 are each a hydrogen atom, or an alkyl group, aryl group, allyl group, or vinyl group with or without a substituent, and they may be the same or different.) A substituted imidazole compound represented by the general formula ▲ mathematical formula,
There are chemical formulas, tables, etc. ▼ (R_5 in the formula is an alkyl group or aryl group with 8 or more carbon atoms, with or without a substituent, R_6 and R
_7 is an alkyl group or an aryl group, each with or without a substituent, and they may be the same or different from each other), a tertiary amine compound represented by the general formula ▲ mathematical formula , chemical formulas, tables, etc. ▼ (R_8 in the formula is an alkyl group or aryl group with 8 or more carbon atoms, with or without a substituent) and the general formula ▲ Numerical formulas, chemical formulas, tables, etc. etc. ▼ [R_9, R_1_0, R_1_1 and R_1_ in the formula
2 is -(C_2H_4O)-_x-(C_3H
A random copolymer or block copolymer represented by _8O)-_yH (where x and y are numbers that satisfy the following relationships: x+y=1 to 20, x=0 to 20, and y=0 to 20) , which may be the same or different from each other.
Compositions as described in Section.