JP3252527B2 - Polyoxymethylene resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyoxymethylene resin composition having excellent initial color tone, color tone stability during heat aging, and heat stability.

[0002]

2. Description of the Related Art Polyoxymethylene resins are known as engineering plastics having a good balance between mechanical strength and impact resistance, and are used in a wide range of fields as electronic equipment and automobile parts. In recent years, polyoxymethylene resins are increasingly used for parts used under severe conditions such as outdoors and under high temperatures. However, polyoxymethylene resin has poor thermal stability due to its structure.Therefore, various antioxidants such as hindered phenols and formaldehyde scavengers that trap formaldehyde generated by decomposition have been used to provide thermal stability. Formulations of various heat stabilizers have been studied.

For example, as a method for improving the thermal stability of a polyacetal resin, Japanese Patent Publication No. 34-5440 discloses a polyoxymethylene resin composition containing a polyamide resin. Further, Japanese Patent Publication No. 40-21148 and Japanese Patent Application Laid-Open No. 4-81449 disclose a polyoxymethylene resin composition containing a compound of cyanoguanidine, benzoguanamine, melamine or the like.

[0004]

[Problems to be solved by the invention]
The polyoxymethylene resin composition containing the polyamide resin disclosed in Japanese Patent Application Laid-Open No. 4-5440 has excellent thermal stability at high temperatures and for a long time, but is affected by the action of formaldehyde generated and the action of oxygen. There is a problem that the color is changed to yellow-brown or a red-brown foreign substance is generated during molding, resulting in a large number of defective moldings. In addition, Tokiko Sho 40-2
The methods disclosed in JP-A No. 1148 and JP-A-4-81449 have a problem that the effect of improving the thermal stability is small and the additive bleeds out when left at a high temperature for a long time.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a polyoxymethylene resin composition containing a specific triazine compound with respect to the polyoxymethylene resin has been developed. The inventors have found that the color tone and the color tone stability during heat aging and the thermal stability are excellent, and have reached the present invention.

That is, the present invention relates to (A) 100 parts by weight of polyoxymethylene resin and (B)

Embedded image (However, in the formula, R _{1 to} R ₄ represent a hydrogen atom or an organic residue, which may be the same or different, and at least one of R _{1 to} R ₄ represents a hydrogen atom.) 0.001 to 1 of the represented triazine compound
It is a polyoxymethylene resin composition containing 0 parts by weight.

[0007] (A) polyoxymethylene resins used in the present invention, oxymethylene homopolymer, and mainly consists of oxymethylene units, oxy least one C2-8 in the polymer backbone Contains alkylene units
Is oxymethylene copolymer ing to.

As the oxymethylene homopolymer, an oxymethylene homopolymer stabilized by substituting an unstable hydroxyl group at a terminal with an ester group or an ether group is preferably used. For example, anhydrous formaldehyde is introduced into an organic solvent containing a basic polymerization catalyst such as an organic amine, an organic or inorganic tin compound, or a metal hydroxide, polymerized, and the polymer is separated by filtration. And oxymethylene homopolymer obtained by heating in the presence of sodium acetate to acetylate the terminal.

As the oxymethylene copolymer, for example, anhydrous trioxane or a cyclic oligomer of formaldehyde such as tetraoxane and at least one cyclic ether or cyclic formal as a copolymerization component are combined with cyclohexane or benzene. After dissolution or suspension in an organic solvent, a polymer produced by adding a Lewis acid catalyst such as boron trifluoride / diethyl etherate, polymerizing, and decomposing and removing unstable terminals can be used. Alternatively, one obtained by introducing a pre-mixture of trioxane and a copolymerization component / catalyst into a self-cleaning type stirrer without using any solvent and performing bulk polymerization may be used. If desired, after removing the catalyst from the polymer by washing, or after deactivating the catalyst with a deactivator,
It is produced by decomposing and removing unstable terminals. It is particularly preferred that trioxane and cyclic ether or cyclic formal are subjected to bulk polymerization in the presence of a Lewis acid catalyst such as boron trifluoride / diethyl etherate, and then the polymerization reaction is stopped by adding a hindered amine compound. And an oxymethylene copolymer obtained by decomposing and removing unstable terminals.

The triazine compound (B) used in the present invention is represented by the following general formula.

[0011]

Embedded image (In the formula, R _{1 to} R ₄ represent a hydrogen atom or an organic residue, which may be the same or different from each other, and at least one of R _{1 to} R ₄ represents a hydrogen atom.) Specifically, 2,4-diamino-6-vinyltriazine, 2,4-di (N-methylamino) -6-vinyltriazine, 2,4-di (N-ethylamino) -6-vinyltriazine, , 4-di (N-isopropylamino) -6-vinyltriazine, 2,4-di [N- (n-
Propyl)]-6-vinyltriazine, 2,4-di (N
-Hydroxymethylamino) -6-vinyltriazine,
2-amino-4- (N-methylamino) -6-vinyltriazine, 2-amino-4- (N-ethylamino) -6
-Vinyltriazine, 2-amino-4- [N- (n-propylamino)]-6-vinyltriazine, 2-amino-4- (N-isopropylamino) -6-vinyltriazine, 2-amino-4- (N-hydroxymethylamino) -6-vinyltriazine and the like. Also,
The addition amount is 0.001 to 10 parts by weight based on 100 parts by weight of the polyoxymethylene resin. If the amount of the triazine compound is less than 0.001, the effect of the addition is small. On the other hand, when the amount is more than 10 parts by weight, bleeding of the additive is observed, which is not preferable.

When the hindered phenol compound (C) is used, those having a molecular weight of 400 or more can be used. Specifically, triethylene glycol-bis [3- (3-t
-Butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate], pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N'-hexamethylenebis (3,5-di-t-butyl-4) -Hydroxyhydrocinnamamide), 2-t-butyl-6- (3'-t-butyl-5'-methyl-2'-hydroxybenzyl) -4-
Methylphenyl acrylate, 3,9-bis [2- {3
-(3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,
5] Undecane and the like. Among them, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,
6-hexanediol-bis [3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate],
Pentaerythrityl-tetrakis [3- (3,5-di-
t-butyl-4-hydroxyphenyl) propionate] is particularly preferred. If the molecular weight is less than 400, the bleeding phenomenon is remarkable, and the appearance of the polyoxymethylene resin composition is impaired and the thermal stability is undesirably reduced.

The amount of polyoxymethylene resin 1
0.01 to 10 parts by weight, preferably 0.05 to 3.0 parts by weight, per 100 parts by weight. 0.0
When the amount is less than 1 part by weight, the thermal stability of the polyoxymethylene resin composition is not sufficient, and when the amount is more than 10 parts by weight, a change in color tone is large and a bleeding phenomenon is observed.

(D) When a hindered amine compound is used, a compound having a molecular weight of 400 or more can be used. Specifically, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1 , 2,2,6,6-pentamethyl-4-piperidyl) sebacate, dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-
2,2,6,6-tetramethylpiperidine polycondensate,
N, N'-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,2,2,
6,6-pentamethyl-4-piperidyl) amino] -6
-Chloro-1,3,5-triazine condensate, poly [$ 6
-(1,1,3,3-tetramethylbutyl) amino-
1,3,5-triazine-2,4-diyl {(2,
2,6,6-tetramethyl-4-piperidyl) imino}
Hexamethylene ｛(2,2,6,6-tetramethyl-4
-Piperidyl) imino｝] and the like. Among them, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethyl Piperidine polycondensate, N, N'-bis (3-
Aminopropyl) ethylenediamine 2,4-bis [N
-Butyl-N- (1,2,2,6,6-pentamethyl-
4-piperidyl) amino] -6-chloro-1,3,5-
Triazine condensate, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-
2,4-diyl {(2,2,6,6-tetramethyl-
4-piperidyl) imino {hexamethylene} (2,2
6,6-tetramethyl-4-piperidyl) imino}] is particularly preferred. If the molecular weight is less than 400, the bleeding phenomenon is remarkable, and the appearance of the polyoxymethylene resin composition is impaired and the thermal stability is undesirably reduced.

The amount of polyoxymethylene resin 1
0.01 to 10 parts by weight, preferably 0.01 to 3.0 parts by weight, per 100 parts by weight. 0.0
If the amount is less than 1 part by weight, the thermal stability of the polyoxymethylene resin composition is not sufficient, and if it is more than 10 parts by weight, coloring by heat is severe, which is not preferable. As a method for producing the polyoxymethylene resin composition of the present invention, a generally known method can be employed. For example, a method of adding the stabilizer used in the present invention in the polymerization or stabilization step of the polyoxymethylene resin, mixing the polyoxymethylene resin and the stabilizer used in the present invention in the form of pellets, powder, or granules, Although melt processing may be performed as it is, a method of melt mixing using a Banbury mixer, a roll, an extruder, or the like can also be employed. Further, a method in which the stabilizer used in the present invention is melt-kneaded with a commercially available polyoxymethylene resin in the same manner as described above can also be employed. Particularly, a method of melt-mixing at a temperature of 150 to 250 ° C. using a single-screw or twin-screw extruder is preferred.

The resin composition of the present invention contains fillers such as calcium carbonate, calcium stearate, barium sulfate, clay, titanium oxide, silicon oxide, mica powder, and glass beads as long as the effects of the present invention are not impaired. Reinforcing agents such as carbon fiber, glass fiber, ceramic fiber, aramid fiber, potassium titanate fiber, coloring agents (pigments, dyes),
Nucleating agent, plasticizer, release agent such as ethylene bis stearamide, polyethylene wax, conductive agent such as carbon black, antioxidant such as thioether compound, phosphite compound, benzophenone compound, benzotriazole Additives such as light stabilizers such as system compounds, pressure-sensitive adhesives, lubricants such as metal soaps, hydrolysis resistance improvers, and adhesion aids can be arbitrarily contained. The polyoxymethylene resin obtained according to the present invention comprises a sensor, L
ED lamp, connector, socket, resistor, relay case, switch, coil hobbin, condenser, variable condenser case, optical pickup, oscillator, various terminal boards, transformer, plug, printed board, tuner, speaker,
Microphone, headphone, small motor, magnetic head base, power module, semiconductor, liquid crystal, FDD
Carriage, FDD chassis, magnetic tape cassette reel, motor brush holder, parabolic antenna,
It is suitably used for electric and electronic parts such as computer-related parts, but other uses such as VTR parts, VTR camera parts, TV parts, irons, hair dryers, shavers, electric fans, juicers, rice cooker parts, and electronic parts Home and office electrical products, such as range components, headphone stereos, radio cassettes, audio / laser discs, compact discs, and other audio equipment components, lighting components, refrigerator components, air conditioner components, typewriter components, calculators, word processor components, etc. Office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, cleaning jigs, motor parts, machine-related parts represented by lighters, typewriters, etc., microscopes, binoculars, cameras, watches, etc. Optical equipment, precision equipment Related parts, alternator terminal, alternator connector, IC regulators,
Potentiometer base for light drier, various valves such as exhaust gas valve, various pipes related to fuel, exhaust system, intake system, air intake nozzle snorkel, intake manifold, fuel pump, engine cooling water joint, carburetor main body, carburetor spacer, Exhaust gas sensor, cooling water sensor, hot water temperature sensor, brake pad wear sensor, throttle position sensor, crankshaft position sensor,
Air flow meter, brake pad wear sensor,
Thermostat base for air conditioner, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, dust distributor, starter switch, starter relay, transmission wire harness, air conditioner panel switch base, Fuel-related electromagnetic valve coil, fuse connector, horn terminal, electrical component insulation board, step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, solenoid hobbin, engine oil filter, radiator drain cock, in-tank fuel pump , Diaphragm valve, auto antenna gear case, door lock, turn signal switch, wiper gear , Wiper pivot bearing, speedometer gear, parts, housing, window glass bottom channel, seat belt housing, seat belt retractor parts, heater control lever, inside door handle, regulator handle, outer door handle, sun visor bracket, collapse lumps Mirror stays, seat hooks, fender mirror cases, fuel caps, window washer nozzles, ignition and other automotive and vehicle-related parts, bicycles, lawnmowers, partition corner pieces, curtain liners, blind gears, door wheels, office furniture parts, various fasteners , Plumbing systems, hose joints, valves, bindings, adjustments, various fasteners, meters, shoe parts, toys, orgos Le,
Beauty parts such as combs, caster brackets, rollers,
It can also be used for caps, major parts, aerosol bottles, sports equipment, and various other general equipment parts.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

[0018]

The present invention will be described below with reference to examples. All percentages and parts in the examples are on a weight basis.

Further, the mechanical properties, thermal stability test and heat aging resistance test of the molded articles shown in Examples and Comparative Examples were conducted as follows.

Molding: Using an injection molding machine having an injection capacity of 5 ounces, cylinder temperature 190 ° C., mold temperature 80
C. and a molding cycle of 30 seconds, an ASTM No. 1 dumbbell test piece was injection molded.

Thermal decomposition rate of oxymethylene copolymer:
Kx means the decomposition rate when left for a certain time at x ° C.
About 10 mg of the sample was allowed to stand at x ° C. in a nitrogen atmosphere using a thermobalance device, and was determined by the following equation.

Kx = (W ₀ −W ₁ ) / W ₀ × 100% W ₀ : Weight of sample before heating W ₁ : Weight of sample after heating Initial color tone: YI of ASTM No. 1 dumbbell specimen obtained by injection molding. (Yellow index) value is SM
It was measured by a color computer (Suga Test Machine).

Mechanical properties: AS obtained by the above injection molding
ASTM D-638 using a TM1 dumbbell specimen
The tensile strength was measured according to the method.

Heat aging resistance test: The ASTM No. 1 dumbbell test piece obtained by the above injection molding was aged in a gear oven heated to 150 ° C. for 50 days,
The tensile strength and the color tone of the dumbbell were measured.

In the examples and comparative examples, the oxymethylene copolymer (P-1) produced by the following method was used as the polyoxymethylene resin (A).

Method for producing oxymethylene copolymer (P-1) Trioxane (25 kg / h) was placed in a twin-screw extruder type polymerization machine (100 mmφ, cylinder length (L) / cylinder diameter (D) = 10.2). , 1,3-dioxolane (810g
/ H), and as a catalyst for trioxane, 110
ppm of boron trifluoride / diethyl etherate (2.
5% benzene solution), 700 ppm as molecular weight regulator
Was supplied, and continuous polymerization was carried out. The polymerization was performed by controlling the outer jacket at 60 ° C. and rotating at 50 rpm. Methylal dissolved in trioxane. Further, a premixing zone was provided so that 1,3-dioxolane and the catalyst solution were premixed immediately before being supplied to the polymerization machine. 23.0 kg of polymer as white fine powder
/ H.

The following (B) the triazine compound represented by the general formula (1), (C) the hindered phenol compound, and (D) the hindered amine compound used in Examples and Comparative Examples are as follows.

(B) Triazine compound represented by formula (1): B-1: 2,4-diamino-6-vinyltriazine B-2: 2,4-di (N-methylamino) -6 -Vinyl triazine.

(C) Hindered phenol compound AO-1: triethylene glycol-bis [3- (3
-T-butyl-5-methyl-4-hydroxyphenyl)
Propionate] (Ciba Geigy “Irganox” 2
45) AO-2: 1,6-hexanediol-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate] (Ciba Geigy “Irganox” 2
59) AO-3: pentaerythrityl-tetrakis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate] (Ciba Geigy “Irganox” 1
010).

(D) Hindered amine compound HA-1: bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (Sankyo "Sanol" LS)
765) HA-2: Dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate (Ciba Geigy “Tinuvin” 6)
HA-3: N, N'-bis (3-aminopropyl) ethylenediamine 2,4-bis [N-butyl-N-
(1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate (Ciba Geigy "Chimassorb" 119FL).

Examples 1 to 9 and Comparative Examples 1 to 4 With respect to 5 kg of polyoxymethylene resin (P-1), (B) a triazine compound, (C) a hindered phenol compound, (D) The hindered amine compound was added, the mixture was stirred in a Henschel mixer for 3 minutes, and melt-extruded and kneaded at 200 to 210 ° C./10 mm torr using a biaxial 45 mmφ extruder with a vent manufactured by Ikegai Iron Works. In Comparative Example 3, (B) melamine (B-) was used in place of the triazine compound represented by the general formula (1).
3) was compared with alkoxymethylmelamine (B-
4) was used.

[0032]

[Table 1]

The resulting composition was extruded as strands and pelletized by a cutter. After drying the pellets at 80 ° C. for 3 hours in a hot air circulating oven,
Molding was performed and used for measurement of mechanical properties. Also molded A
Gears with STM No. 1 dumbbell specimen heated to 150 ° C
After aging in an oven for 50 days, the tensile strength and the color of the dumbbell were measured.

Table 2 summarizes the results.

[0035]

[Table 2]

From these results, it is clear that the polyoxymethylene resin composition of the present invention is excellent in initial color tone, color tone stability during heat aging, and heat stability.

[0037]

The polyoxymethylene resin composition of the present invention is excellent in initial color tone, color tone stability during heat aging, and heat stability. Therefore, it is easy to mold because of its excellent initial color tone, color tone stability during heat aging, and thermal stability, and it can be widely used as a mechanical mechanism part in the electric / electronic field, automobile field, etc. it can.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 59/00-59/04

Claims (5)

(57) [Claims] (A) 100 parts by weight of a polyoxymethylene resin, (B) the following general formula: (However, in the formula, R _{1 to} R ₄ represent a hydrogen atom or an organic residue, and may be the same or different, provided that at least one of R _{1 to} R ₄ represents a hydrogen atom.) The triazine compound represented by
A polyoxymethylene resin composition containing 10 parts by weight. 2. (A) 100 parts by weight of a polyoxymethylene resin, (B) the following general formula: (However, in the formula, R _{1 to} R ₄ represent a hydrogen atom or an organic residue, which may be the same or different, and at least one of R _{1 to} R ₄ represents a hydrogen atom.) 0.001 to 1 of the represented triazine compound
0 parts by weight, (C) 0.01 to 10 parts by weight of a hindered phenol compound having a molecular weight of 400 or more, (D) molecular weight of 40
A polyoxymethylene resin composition containing 0.01 to 10 parts by weight of a hindered amine compound of 0 or more. 3. The method of claim 2, wherein (B) the triazine compound is 2,4-diamino-6-vinyltriazine, 2,4-di (N-methylamino) -6-vinyltriazine, or 2,4-di (N-ethylamino). -6-vinyltriazine, 2,4-di (N
-Isopropylamino) -6-vinyltriazine, 2,
4-di [N- (n-propyl)]-6-vinyltriazine, 2,4-di (N-hydroxymethylamino) -6
Vinyltriazine, 2-amino-4- (N-methylamino) -6-vinyltriazine, 2-amino-4- (N-
Ethylamino) -6-vinyltriazine, 2-amino-
4- [N- (n-propylamino)]-6-vinyltriazine, 2-amino-4- (N-isopropylamino)
The polyoxymethylene resin composition according to claim 1 or 2, which is at least one compound selected from -6-vinyltriazine and 2-amino-4- (N-hydroxymethylamino) -6-vinyltriazine. 4. The (C) hindered phenol compound having a molecular weight of 400 or more is triethylene glycol-bis [3
-(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-
From bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] 3. The polyoxymethylene resin composition according to claim 2, which is one or more selected compounds. 5. The method according to claim 1, wherein (D) the hindered amine compound having a molecular weight of 400 or more is bis (2,2,6,6-tetramethyl-
4-piperidyl) sebacate, bis (1,2,2,6)
6-pentamethyl-4-piperidyl) sebacate, dimethyl succinate / 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, N, N′-bis (3 -Aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,
2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, poly [{6- (1,1,3,3-tetramethylbutyl) amino] -1,3,5-Triazine-2,4-diyl
｛(2,2,6,6-tetramethyl-4-piperidyl)
The polyoxymethylene resin composition according to claim 2, which is at least one compound selected from imino {hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}.