JPH02261854A - Oxymethylene polymer composition - Google Patents

Abstract

PURPOSE:To improve the light resistance by compounding an oxymethylene polymer with an ultraviolet absorber, two specific light stabilizers, and polyethylene glycol. CONSTITUTION:100 pts.wt. oxymethylene polymer is compounded with 0.01 to 5 pts.wt. benzotriazole and/or oxalic anilide ultraviolet absorber {e.g. 2-[2'- hydroxy-3',5'-bis(alpha,alpha-dimethylbenzyl)phenyl]benzotriazole}, 0.01 to 3 pts.wt. hindered amine light stabilizer of formula I (wherein R is a piperdiene deriv. of formula II; Y is H, OH, alkyl or acyl; X is formula III; (m) is 1-4; and (n) is 1 to 10), 0.01 to 3 pts.wt. hindered amine light stabilizer of formula IV [wherein R1 and R2 are each alkyl; (l) is 1 to 3; when (l) is 1, R3 is a monovalent acyl, (cyclo)alkyl, aryl, aralkyl, etc.; when (l) is 2, R3 is diacyl, dicarbamoyl, carbonyl, etc.; and when (l) is 3, R3 is triacyl or alkanetoluoyl], and 0.01 to 10 pts.wt. polyethylene glycol.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a novel oxymethylene polymer composition with excellent weather resistance.

More particularly, the present invention relates to oxymethylene polymer compositions that have superior resistance to outdoor exposure and irradiation with sunlight and ultraviolet light compared to conventional oxymethylene polymer compositions.

(Conventional technology) Oxymethylene polymers have excellent mechanical properties, friction resistance and
Because it has wear characteristics, fatigue resistance characteristics, electrical characteristics, thermal characteristics, chemical resistance, etc., it is widely used as an engineering resin for mechanical parts in automobiles, electrical and electronic fields, etc.

However, this oxymethylene polymer itself has drawbacks such as cracks occurring on the surface of molded products due to light energy such as sunlight and ultraviolet rays, causing a decrease in strength, and discoloration and fading in the case of colored molded products. are doing. Therefore, when using oxymethylene polymers in parts that are exposed to sunlight, it is necessary to use compositions containing various weathering agents, and various weathering agents have been proposed so far.

For example, the combined use of a hindered amine light stabilizer and an oxalic acid anilide ultraviolet absorber (Japanese Unexamined Patent Publication No. 5798545), the combined use of a hindered amine light stabilizer and a benzophenone ultraviolet absorber (Japanese Patent Application Laid-Open No. 59-133245) , JP-A-61-113649), combined use of benzotriazole-based ultraviolet absorbers and hindered amine-based light stabilizers (JP-A-60-195155, JP-A-61)
-36339), a combination of various ultraviolet absorbers, aliphatic esters, and hindered amine light stabilizers (JP-A-6
1-47744) and the like have been proposed. Also,
Polymer material composition containing ultraviolet absorber
-7292, etc.), polymeric material compositions containing hindered amine light stabilizers (Japanese Patent Application Laid-open No. 61-1.677)
Publication No. 5, etc.) have been disclosed.

However, although the weather resistance of oxymethylene polymer compositions containing weathering agents such as ultraviolet absorbers and light stabilizers is certainly improved compared to those without them,
I still can't say it's enough.

Furthermore, even if an increased amount of weathering agent is added in the hope of improving weather resistance, the thermal stability of the composition will be significantly reduced, silver streaks will appear on the molded product due to decomposition gas, and the appearance of the molded product will deteriorate significantly. . In this way, many practical problems arise.

(Problems to be Solved by the Invention) The present invention overcomes the drawbacks of conventional oxymethylene polymer compositions, and enables molded products to withstand long-term exposure to outdoor exposure, sunlight, and ultraviolet rays. The purpose of this invention is to provide an oxymethylene polymer composition with excellent weather resistance, which has extremely few cranks on the surface, significantly suppresses discoloration and fading, and has no decrease in thermal stability.

(Means for Solving the Problems) The present inventors have conducted intensive research to develop an oxymethylene polymer composition that has even higher weather resistance and does not reduce thermal stability. In the methylene polymer, at least one UV absorber selected from benzotriazole-based and oxalic acid anilide-based UV absorbers, two types of hindered amine light stabilizers with specific structures, and polyethylene glycol were identified as weathering agents. It has been discovered that the above object can be achieved by mixing the ingredients in proportion, and based on this knowledge, the present invention has been completed.

That is, the present invention provides: (A) With respect to 100 parts by weight of the oxymethylene polymer, (B) at least one ultraviolet absorber 1 (1,01
~5 parts by weight, a piperidine derivative represented by (Y in the formula represents a hydrogen atom, oxyl, alkyl group or acyl group), X is (cHcoo+).

CHICOO-, m represents 1-4, and n represents 1-10. ] 0.01 to 3 parts by weight of a hindered amine light stabilizer represented by (D) General formula: [In the formula, R is the general formula: [In the formula, R1 and R2 are the same or different alkyl groups, , 2 is l, 2 or 3, and R5 is ! When =1, -valent acyl group, alkyl group, cycloalkyl group, aryl group, aralkyl group, N-tlftAlft
or a piperidine derivative represented by the general formula: (in which Ro and R1 are the same or different alkyl groups), and when f=2, a diacyl group, dicarbamoyl group, carbonyl group , represents an alkylene group, arylene group or arylene dialkylene group, and when f=3 represents a triazyl group or an alkantolyl group. 0.01 to 3 parts by weight of a hindered amine light stabilizer represented by ] and (E) 0.01 to 10 parts by weight of polyethylene glycol, to provide an oxymethylene polymer composition with excellent weather resistance. It is something to do.

The present invention will be explained in detail below.

In the composition of the present invention, the oxymethylene polymer used as component (A) may be an oxymethylene homopolymer or a copolymer in which oxymethylene chains occupy the majority.

Further, there is no particular restriction on the degree of polymerization, but it is preferable that it can withstand normal molding processes and exhibit the inherent mechanical strength of oxymethylene polymers.

In the composition of the present invention, the ultraviolet absorber used as component (B) is selected from benzotriazole-based and oxalic acid anilide-based ultraviolet absorbers.

Examples of benzotriazole ultraviolet absorbers include:
2-(2°-hydroxy-5°-methylphenyl)benzotriazole, 2-(2°-hydroxy-3°,5″-
di-t-butyl-phenyl)benzotriazole, 2-
(2″-hydroxy-3°, 5″-di-isoamyl-
phenyl)benzotriazole, 2-(2°-hydroxy-3′5°-bis-(α,α-dimethylbenzyl)phenyl]benzotriazole, 2-(2hydroxy-4′-octoxyphenyl)benzotriazole, etc. Can be mentioned.

On the other hand, examples of the chelate anilide ultraviolet absorber include 2-ethoxy-2°-ethyl oxalic acid bisanilide, 2-ethoxy-5-t-butyl-2°-
Examples include ethyl oxalic acid bisanilide, 2-ethoxy-3°-dodecyl oxalic acid bisanilide, and the like.

Among these, 2-[2°-hydroxy-3°5”-bis(α,α-dimethylbenzyl)phenyl]benzotriazole is preferred. Each of these ultraviolet absorbers may be used alone, or You may use two or more types in combination.

The amount of the benzotriazole UV absorber as component (B) in the composition of the present invention is 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the oxymethylene polymer. parts, more preferably from 0.1 to
The amount is selected within the range of 1.5 parts by weight. This amount is 0.01
If it is less than 5 parts by weight, sufficient weather resistance will not be obtained, and if it exceeds 5 parts by weight, thermal stability will decrease and silver streaks or retained coloration will tend to occur during molding, which is undesirable. .

In the composition of the present invention, the hindered amine light stabilizer used as component (C) is -maximum: [in the formula, R is
- Maximum: (Y in the formula represents hydrogen, atom, hydroxyl group, alkyl group or acyl group)
O- is a veridine derivative, and X is (cucoosu).

CHICOO-, m is 1 to 4, and n is 1 to 10.

In the above -maximum (1), R is an N-substituted 2゜2,6.6-titramethylbiveridine residue represented by -maximum: and is introduced via an ester bond. The number of R contained in one molecule is determined by m and n,
The minimum is 4 when m and n are l, respectively, and the maximum is 46 when m and n are 4 and 10, respectively. In this way, the hindered amine photostabilizer represented by -maximum (1) has a large number of N-substituted 2,2,6,6-titramethylpiveridine residues in its molecule, which makes it photostable. Demonstrates excellent effects as an agent.

Y in the above-mentioned maximum (n) is a hydrogen atom, a hydroxyl group, an alkyl group, or an acyl group, which may have a substituent group.

Examples of the alkyl group include a methyl group, a methyl group,
Propyl group, isopropyl group, butyl group, amyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, octadecyl group, benzyl group, phenylethyl group, 2-hydroxyethyl group, 2
-Hydroxypropyl group, 2-hydroxybutyl group, 2
, 3-epoxyprobyl group, and the like.

Examples of the acyl group include an acetyl group, a propionyl group, a butyroyl group, an acryloyl group, a methacryloyl group, an octanoyl group, and a benzoyl group.

X in the above -maximum (1) is -maximum:cozcoo
- (CHCOO-h ・ ・ ・ ・ (V)
It is a polyvalent acyloxy group represented by cn, coo ~ (m in the formula is 1 to 4). This polyvalent acyloxy group has the general formula: CHtCOOH "(CHCOO)I), . . . .
(Vl) cutcoon (in the formula, n is 1 to 4). Examples of such polycarboxylic acids include propane-1,2,3
-1-licarboxylic acid, butane-1,2゜3.4-tetracarboxylic acid, pentane-1,2゜3.4.5-pentacarboxylic acid, hexane-1゜2.3,4,5.6- Hexacarboxylic acids may be mentioned, but propane-1,2,3-tricarboxylic acid and butane-1,2,3,4-tetracarboxylic acid are preferred.

In the composition of the present invention, one type of the hindered amine light stabilizer may be used, or two or more types may be used in combination, and the blending amount is 0.01 to 3 parts by weight per 100 parts by weight of the polyacetal resin. parts by weight, preferably 0.05
-1.5 parts by weight. This amount is 0.0
If it is less than 1 part by weight, sufficient weather resistance will not be obtained, and if it exceeds 3 parts by weight, thermal stability will decrease.

In the composition of the present invention, the hindered amine light stabilizer used as component (D) is -a2: [in the formula, R1 and R2 are the same or different alkyl groups, and 2.2 is 1.2 or 3; , R1 is a -valent acyl group, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an N-substituted rubamoyl group, or - when l=1.
Maximum; represents a piperidine derivative represented by (in the formula, R1 and R1 represent the same or different alkyl groups), and ! When =2, it represents a diacyl group, dicarbamoyl group, carbonyl group, alkylene group, arylene group, or arylene dialkylene group, and when j2 = 3, it represents a triazyl group and an alkantolyl group. have.

In the above-mentioned maximum (I[[), R1 and R8 are the same or different alkyl groups, such as methyl group, ethyl group, isopropyl group, dodecyl group, etc., and R
1 and R3 may be bonded through a carbon atom to form a ring.

R1 is! When it is -1, it is a -valent acyl group, alkyl group, cycloalkyl group, aryl group, aralkyl group or N-substituted rubamoyl group. Examples of these include acetyl group, propionyl group, butyryl group, stearoyl group, acryloyl group, benzoyl group, phenoxyacetyl group, cyclohexanoyl group, α-naphthoyl group,
Ethylcarbamoyl group, n-butylcarbamoyl group, methyl group, ethyl group, n-butyl group, octyl group, styryl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, benzyl group, phenethyl group, phenyl group, tolyl group, naphthyl group Examples include groups.

Also <R+ is! When =2, it is a diacyl group, dicarbamoyl group, carbonyl group, alkylene group, arylene group, or arylene dialkylene group.

Examples of these include carbonyl group, oxalyl group, malonyl group, adipyl group, sepatyl group, fumaryl group, terephthalyl group, methylene group, ethylene group, propylene group, hexamethylene group, O-phenylene group, p-xylylene group,
Examples include tolylene-2,4-dicarbamoyl group, hexamethylene-1,6-dicarbamoyl group, and R4.

Further, when 2=3, R1 is a triazyl group or an alkantriyl group, and for example, benzene-1,3
, 5-tricarbonyl group, benzene-1,3,4-)licarbonyl group, cyclohexane-1,3,5-)licarbonyl group, propan-1,2,3-yl group, hexane-
Examples include 1,3,6-yl group.

Specific examples of the hindered amine light stabilizer of component (D) include 4-acetoxy-2,2,6°6-titramethylbiveridine, 4-stearoyloxy-2,2,6
, 6-titramethylbiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(phenylacetoxy)-2,2,6,6-titramethylbiperidine, 4- Benzoyloxy-2,2,6,6-titramethylbiperidine, 4-methoxy-2,266-titramethylpiperidine, 4-stearyloxy-2,2
, 6,6-titramethylpiperidine, 4-cyclohexyloxy-2,2,6゜6-titramethylbiperidine,
4-benzyloxy-2,2,6,6-titramethylbiperidine, 4-phenoxy-2,2,6,6-titramethylpiperidine, 4-(ethylcarbamoyloxy)-
2,2,6,6-titramethylpiperidine, 4-(cyclohexylcarbamoyloxy)-2゜2.6.6-titramethylpiperidine, 4-(phenylcarbamoyloxy)-2,2,6,6- Titramethylbiperidine, bis(2,2,6゜6-tetramethyl-4-piperidyl)
-carbonate, bis(2,2,6,6-tetramethyl4-piperidyl)-oxalate, bis(2,2°6.
6-tetramethyl-4-piperidyl)-malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)-
Adipate, bis(2,26,6-tetramethyl-4-
piperidyl) sebacate, bis(2,2,6,6-tetramethyl4-piperidyl)-terephthalate, 1.2-
Bis(2,2,6,6-tetramethyl-4-piperidyloxy)-ethane, α, α°-bis(2,2°6.6-
tetramethyl-4-piperidyloxy) p-xylene,
Bis(2,2,6,6-tetramethyl-4-piperidyl)tolylene-2,4-dicarbamate, bis(2,2,
6,6-tetramethyl-4-piperidyl)-hexamethylene-16-dicarbamate, tris(2,2,6,6
-tetramethyl-4-piperidyl)-benzene-1゜3
．． 5-tricarboxylate, tris(2,2°6.6
-tetramethyl-4-piperidyl)-benzene-1,3
, 4-tricarboxylate, etc. Among these, bis(2,2,6゜6-tetramethyl-4-
piperidyl)-sebacate, bis(2,2,6,6-
Tetramethyl-4-biveridyl)-adipate, 4-benzoyloxy-2,2,6,6-titramethylpiveridine, 4-(phenylcarbamoyloxy)-2,26
, 6-titramethylbiveridine and the like are preferred.

These hindered amine light stabilizers may be used alone or in combination of two or more.

The amount of the hindered amine stabilizer as component (D) in the composition of the present invention is 100 f of oxymethylene weight.
0.01 to 3 parts by weight, preferably 0.0 parts by weight per part of E
Selected in the range of 5 to 1.5!11 parts. This amount is o
If it is less than 3 parts by weight, sufficient weather resistance cannot be obtained, and if it exceeds 3 parts by weight, thermal stability will decrease and silver streaks will occur due to decomposed gas during molding, resulting in poor appearance of the molded product. becomes significantly worse, which is not desirable.

In the composition of the present invention, polyethylene glycol is used as component (E). This polyethylene glycol has an average molecular weight in the range of 600 to 20,000, preferably 3,000 to 10,000.
belongs to.

The amount of the polyethylene glycol as the component (E) in the composition of the present invention is 0.01 to 10 parts by weight, preferably 0.1 parts by weight, based on 100 parts by weight of the oxymethylene polymer.
-5 parts by weight. If the amount is less than 0.01 part by weight, no dramatic improvement in weather resistance will be achieved, and if it exceeds 10 parts by weight, the thermal stability will decrease, and furthermore, the original strength of the oxymethylene polymer will decrease significantly. .

The compositions of the present invention may further contain additives commonly used in oxymethylene polymer compositions, such as polyamides, heat stabilizers such as melamine, 2,2"-methylene-bis(4-methyl-6-t-butylphenyl), /-/L, ),) lyethylene glycol bis[3(3-L-butyl-5-methyl-4
-hydroxyphenyl)propionate], antioxidants such as pentaerythrityl-tetrakis (3-(3,5-di-butyl=4-hydroxyphenyl)propionate), antistatic agents, lubricants, glass fibers, carbon fibers,
Reinforcing agents such as potassium titanate fibers and organic fibers, glass pieces, talc, inorganic fillers such as calcium carbonate, nucleating agents, mold release agents, carbon black, pigments, and the like can be blended as desired.

The method for producing the composition of the present invention is not particularly limited, and a method of kneading the above-mentioned components into a molten oxymethylene polymer is generally used.

(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.

Further, in Examples and Comparative Examples, each property was evaluated using a red colored product of each composition.

This is because color changes due to weather resistance evaluation include color changes due to cranking, color changes due to precipitation of additives and decomposed products of oxymethylene polymers on the surface of molded products, and color changes due to deterioration of pigments. This is because it is practically meaningless to evaluate these individually, and it is important for practical use to evaluate them comprehensively.

In addition, each characteristic of the composition in an Example and a comparative example was calculated|required as follows.

■Weather resistance evaluation: The pellet was molded into a 67 x 13 x 3 mm test piece using an injection molding machine, and the test piece was placed in a fade meter (WEL-3UN-HC-B-EM model manufactured by Suga Test Instruments Co., Ltd.), and the black panel temperature was 83 It was exposed under conditions of approximately 50% iW degree and °C. After exposure for 400, 600°, 800°, 1,000, and 1,200 hours, the color difference and degree of cranking were determined under the following conditions.

(A) Color difference: The light irradiated surface of the test piece was measured using a color difference meter (Handy Color Tester HC-T manufactured by Suga Test Instruments) to determine the E value (JIS
Z-8730) was determined.

The smaller the value, the less the color change.

(B) Degree of cranking: The light-irradiated surface of the test piece was observed under a microscope with a magnification of 100 times, and the degree of cranking was evaluated according to the following criteria.

Judgment criteria: 0: No cracks.

1: There are slight cracks.

2: The crack is long and clear.

3: Cracks are long and there are 20 or more cracks in the visual field.

4: Cracks occur across the front surface.

■Thermal stability evaluation: After staying in an injection molding machine for 30 minutes at a material temperature of 230°C, a tanzak piece with a test piece shape of 120 x 12 x 3 m was molded, and the degree of silver streaks on the molded product was observed. Evaluation was made according to the criteria.

Judgment criteria; O: No silver streaks were observed on the surface of the molded product.

Δ: Silver streaks are partially observed on the surface of the molded product.

×: Silver stripes are observed on more than half of the surface of the molded product.

In addition, the symbols in the table indicate the following.

A J benzoazole B-172-(2″-hydroxy-3゛, 5゜t-butylphenyl)benzotriazole B-2: 2-(2°-hydroxy-3″, 5″bis-(α,α- dimethylbenzyl)phenyl)benzotriazole, B-3: 2-(2°-hydroxy-5′-methylbuenyl)benzotriazole, B-4! 2-ethoxy-2′-ethyloxalic acid bisanilide, Ruhinaku : Table 1 D-1: Bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, D-2: Bis(2,2,6,6-tetramethyl-4-piperidyl) adipate , D-3: 4-benzoyloxy-2,2,6,6-titramethylpiperidine, nibo-1 ethylenecol: E-1: Polyethylene glycol with an average molecular weight of about 3000, E-2: Polyethylene glycol with an average molecular weight of about 6000 Polyethylene glycol, Examples 1 to 20 and Comparative Examples 1 to 8 Oxymethylene homopolymer (melt index 1
5 g/10 minutes), 0.3 parts by weight of poly-β-alanine as a heat stabilizer and the composition of the weathering agent shown in Table 2 were mixed homogeneously using a Henschel mixer, and this mixture was The extruded strands were melt-mixed using a twin-screw extruder, and the extruded strands were immediately pelletized and dried. next,
0.2 parts by weight of a pigment (quinacridone red pigment) was blended with 100 parts by weight of the dried pellets, and the mixture was melt-mixed again using a -screw extruder. The colored pellets obtained were dried and used for each evaluation.

The results are shown in Table 2.

Examples 21 to 40 and Comparative Examples 9 to 16 Oxymethylene copolymer obtained by copolymerizing trioxane and 3 mo 1% ethylene oxide (melt index 9 g
1 Io min), 0.10 parts by weight of poly-β-alanine, 0.3 parts by weight of melamine, and the composition of the weathering agent shown in Table 3 were mixed homogeneously using a Henschel mixer, and this mixture was The extruded strands were melt-kneaded using a twin-screw extruder, and the extruded strands were immediately made into pellets.
The mixture was melt-kneaded again using a screw extruder, and the resulting colored pellets were dried and used for each evaluation.

The results are shown in Table 3.

(Effects of the Invention) The oxymethylene polymer with excellent weather resistance of the present invention is produced by combining a specific ultraviolet absorber, two types of hindered amine light stabilizers with specific structures, and polyethylene glycol as weathering agents. Compared to conventional compositions, it causes less cracking than conventional compositions and is extremely resistant to discoloration and fading of colored products when exposed outdoors or under conditions of long-term irradiation with light energy such as sunlight and ultraviolet rays. It is an excellent composition that is small in size (and also has no deterioration in thermal stability during molding).

Therefore, the composition of the present invention is an effective material for parts that require durability against light energy in the automobile, electrical and electronic fields, and the like.

(1 other person)

Claims (1)

Scope of Claims: (A) 0.01 to 5 parts by weight of at least one ultraviolet absorber selected from benzotriazole and oxalic acid anilide based on 100 parts by weight of the oxymethylene polymer (B)
Parts by weight, (C) General formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [R in the formula is the general formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(II) (In the formula Y is a hydrogen atom, a hydroxyl group, an alkyl group, or an acyl group. indicates 1 to 10. ] 0.01 to 3 parts by weight of a hindered amine light stabilizer represented by (D) General formula: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ... (III) [R_1 and R_2 in the formula are , are the same or different alkyl groups, l is 1, 2 or 3, and when R_3 is l = 1, a monovalent acyl group, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an N-substituted carbamoyl group, Or general formula: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ... (IV) Indicates a piperidine derivative represented by (R_4 and R_5 in the formula represent the same or different alkyl groups), l When =2, it represents a diacyl group, dicarbamoyl group, carbonyl group, alkylene group, arylene group, or arylene dialkylene group, and when l = 3, it represents a triacyl group and an alkantolyl group. An oxymethylene polymer composition comprising: 0.01 to 3 parts by weight of a hindered amine light stabilizer represented by the following formula; and 0.01 to 10 parts by weight of polyethylene glycol (E).