JPH06184402A - Weather-resistant polyacetal resin composition - Google Patents

Abstract

PURPOSE:To obtain a polyacetal resin composition suitable for a material used for components of various kinds of apparatuses requiring durability under exposure to light or the air or under exposure to relatively high-energy light rays such as fluorescent lighting. CONSTITUTION:A weather-resistant polyacetal resin composition prepared by admixing (A) one or two or more kinds of weather(light)resistant agents selected from a benzotriazole-based substance, a benzophenone-based substance, an aromatic benzoate-based substance, a cyanoacrylate-based substance and an oxalic acid anilide-based substance, (B) one or two or more compounds of fatty acid esters and (C) one or two or more kinds of compounds of hindered amine-based substances with a polyacetal resin.

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 excellent weather resistance, and is used in various fields such as electric equipment, automobiles, textile machines, cameras, computers, various office equipment, and miscellaneous goods. Polyacetal resin suitable for use as equipment parts, especially for various equipment parts required to have durability under conditions of contact with sunlight or air, or conditions of contact with relatively high-energy rays such as fluorescent lights. A composition is provided.

[0002]

2. Description of the Related Art As is well known, polyacetal resins have recently been used in an extremely wide range of fields as engineering resins having excellent physical properties such as mechanical properties and electrical properties, or chemical properties such as chemical resistance and heat resistance. It's being used. However, with the expansion of fields in which polyacetal resins are used, the properties of the materials are required to be more peculiar. As one of such peculiarities, further improvement in weather resistance may be required. In other words, exterior parts such as automobiles and parts such as electric equipment and office equipment change color or lose surface smoothness due to the atmosphere used, such as sunlight, fluorescent lights, and other atmospheric contact, and lose their luster. May occur, resulting in inconvenience such as deterioration of mechanical properties. In order to prevent these drawbacks, it has been proposed to improve the weather resistance (light) of the polyacetal resin by adding various weather resistance (light) stabilizers to the polyacetal resin.

[0003]

As a weathering (light) stabilizer for a thermoplastic resin that has been proposed hitherto, benzotriazole-based substances, benzophenone-based substances, aromatic benzoate-based substances, hindered amine-based substances, oxalic anilide-based substances are used. There are substances, etc., and these weathering stabilizers are known to have a considerable effect even when applied to polyacetal, but depending on the purpose of use, the surface condition and mechanical properties of the molded product are not always satisfactory. However, there is a case where a material having further excellent weather resistance (light) stability is required. However, even if the amount of the weather resistance (light) stabilizer is simply increased to satisfy such a requirement, there is a limit to the improvement of the weather resistance, and since other characteristic values are hindered, it is often not preferable, and it is economical. I can't avoid the disadvantages.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to further improve weather resistance (light) stability without impairing the excellent physical and chemical properties originally possessed by polyacetal resins. The present invention has been completed.
That is, the present invention, the polyacetal resin (A) a benzotriazole-based substance, a benzophenone-based substance, an aromatic benzoate-based substance, a cyanoacrylate-based substance and one or more kinds of weather resistance selected from the group consisting of anilic acid anilide-based substance ( The present invention relates to a weather-resistant polyacetal resin composition obtained by adding and coexisting (light) stabilizer, one or more kinds of (B) fatty acid ester, and one or more kinds of (C) hindered amine-based substance.

The polyacetal resin used in the present invention may be a polyoxymethylene homopolymer, or a polyacetal copolymer or terpolymer in which most of the main chain is a polyoxymethylene chain. Further, there is no particular limitation on the degree of polymerization or the like.

Next, the weathering (light) stabilizer of the group (A) used in the present invention is selected from benzotriazole type substances, benzophenone type substances, aromatic benzoate type substances, cyanoacrylate type substances and oxalic acid anilide type substances. At least one substance. The amount of these substances added (relative to the total composition) is usually 0.01 to 5% by weight, preferably 0.05 to 2% by weight. Examples of these substances include the following. That is, 2- (2'-hydroxy-5'-methyl-
Phenyl) 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- (2'-hydroxy-4'
-Octoxyphenyl) benzotriazole, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy -4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5
Sulfobenzophenone, 2-hydroxy-4-oxybenzylbenzophenone, pt-butylphenyl salicylate, p-octylphenyl salicylate, 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate, ethyl-2-cyano -3,3'-diphenyl acrylate, N- (2-ethyl-phenyl) -N '-(2-ethoxy-5-t-butylphenyl) oxalic acid diamide, N- (2
-Ethyl-phenyl) -N '-(2-ethoxy-phenyl) oxalic acid diamide and the like.

Next, the fatty acid ester used in the present invention will be described. As is well known, a fatty acid ester is an ester formed from a fatty acid component and an alcohol component. Here, the fatty acid is generally defined as a general term for a carboxylic acid having one carboxyl group (RCOOH) having a chain structure, and includes a straight chain structure and a side chain structure. There are saturated fatty acids and unsaturated fatty acids. Further, those in which a part of the hydrogen is substituted with a substituent having a hydroxyl group degree are also generally defined as included in fatty acids. The fatty acid which is a constituent component of the fatty acid ester used in the present invention also has two or more carbon atoms which meet the above definition, and examples of such fatty acid include acetic acid, propionic acid, butyric acid, Caproic acid, capric acid, undecyl acid, pivalic acid, caprylic acid, lauric acid, tridecyl acid, myristic acid,
Pentadecylic acid, palmitic acid, heptadecyl acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, heptacosanoic acid, montanic acid, melissic acid, laxeric acid, oleic acid, elaidic acid, linoleic acid, linolenic acid , Arachidonic acid, cetoleic acid, erucic acid, etc. It is preferably a fatty acid having 12 or more carbon atoms. The alcohol that is another component used in the preparation of the fatty acid ester is not particularly limited, but it is generally preferable to use a polyhydric alcohol, and as the polyhydric alcohol, ethylene glycol, diethylene glycol, propylene glycol is used. , Glycerin, polyglycerin, trimethylolpropane,
At least one selected from pentaerythritol, sorbitan, or homopolymers and copolymers of polyalkylene glycols such as polyethylene glycol and polypropylene glycol is used. And examples of fatty acid esters obtained from these include ethylene glycol distearate, glycerin monocaprate, glycerin monostearate, glycerin tripalmitate, polyglyceryl tristearate, trimethylolpropane monopalmitate. Ester, pentaerythritol monoundecylate, sorbitan monostearate, polyalkylene glycol monolaurate such as polyethylene glycol, polypropylene glycol, monopalmitate, monostearate or dilaurate, dipalmitate, distearate, dibehenate, dimontanate, dioleate. , And dilinoleate. Among them, an estester of a polyalkylene glycol having an average polymerization degree of 16 or more and a fatty acid having a carbon number of 12 or more is preferable, and an average polymerization degree of 20 to 2 is particularly preferable due to the surface condition of the molded product.
Esters of polyalkylene glycols of 00 are most suitable for use. The amount of the fatty acid ester used in the present invention added to the polyacetal resin is 0.01% by weight based on the total composition.
~ 30% by weight. The preferable addition amount is 0.05 to 10% by weight. If the amount is smaller than this, sufficient weather resistance cannot be obtained, and if the amount is larger than that, extrusion moldability and mechanical properties may be deteriorated, so the range of 0.1 to 5% by weight is preferred. Is preferred.

In the present invention, the weather resistance (light) of the above group (A)
In addition to the stabilizer and the fatty acid ester of (B), one or more of the (C) hindered amine-based substance is mixed and used in combination. The (C) hindered amine-based substance used here is a piperidine derivative having a sterically hindering group, and examples thereof include 4-acetoxy-2,2,6,6-tetramethylpiperidine and 4-stearoyloxy- 2, 2,
6,6-Tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-
Methoxy-2,2,6,6-tetramethylpiperidine,
4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6
6-tetramethylpiperidine, 4-phenoxy-2,
2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-
(Phenylcarbamoyoxy) -2,2,6,6-tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2,2,2
6,6-tetramethyl-4-piperidyl) malonate,
Bis (2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,2)
6,6-Pentamethyl-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) terephthalate, 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) ) Ethane, bis (2,
2,6,6-Tetramethyl-4-piperidyl) hexamethylene-1,6-dicarbamate, bis (1-methyl-)
2,2,6,6-Tetramethyl-4-piperidyl) adipate, Tris (2,2,6,6-tetramethyl-4-)
Piperidyl) benzene-1,3,5-tricarboxylate and the like. Further, a high molecular weight piperidine derivative polycondensate such as dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate is also effective. The amount of the hindered amine-based substance used in the present invention added to the polyacetal resin is 0.05% to 5% by weight based on the total composition. If the amount is smaller than this, sufficient weather resistance cannot be obtained, and if the amount is larger than that, extrusion moldability and mechanical properties may be deteriorated.
A weight% range is preferred.

[0009]

ACTION AND EFFECTS OF THE INVENTION The present invention comprises a polyacetal resin, a weather resistance (light) stabilizer of group (A) and a fatty acid ester (B)
Further, it relates to a composition in which (C) a hindered amine-based substance is added and coexisted. (A) weathering stabilizer and (C) even if a fatty acid ester is added to a system in which no hindered amine-based substance is present,
The weather resistance is not improved, but rather reduces the weather resistance,
Surprisingly, the composition in which (A) the weathering stabilizer and (C) the hindered amine-based substance and (B) the fatty acid ester coexist exhibit a very remarkable synergistic effect, and the (A) weathering stabilizer and (C) It has more remarkable weather resistance (light) stability as compared with the polyacetal resin composition in which only the hindered amine-based substance is added, and has little adverse effect on physical properties, mechanical properties, thermal stability, etc. It was recognized that deterioration of the surface properties of the molded product after exposure to the like, for example, changes in hue, gloss, etc., occurrence of cracks, deterioration of mechanical properties, etc. was observed. Among the fatty acid esters used in the present invention, fatty acid esters of polyhydric alcohols are preferable, and among them, esters of polyalkylene glycol having an average degree of polymerization of 16 or more and fatty acids having 12 or more carbon atoms are preferable from the surface condition of the molded article, and particularly molding An ester of polyalkylene glycol having an average degree of polymerization of 20 to 200 is most suitable for use from the surface condition of the product. Since these fatty acid esters have a higher molecular weight of polyalkylene glycol than others, they are excellent in thermal stability and help disperse weather-resistant stabilizers and hindered amine-based substances, while also allowing appropriate bleeding to cause weather-resistant stabilizers and hindered amines. It is considered that the deterioration of the resin is suppressed by moving the system material to the surface of the molded product, and the deterioration of the surface gloss and the occurrence of cracks on the surface of the molded product are prevented, and it is left under conditions of high temperature and high humidity. However, it has been confirmed that there is no disadvantage that the surface of the molded article is excessively exuded at an accelerated rate and the appearance and function are impaired. The composition of the present invention is based on a polyacetal resin as a base, and it is desirable to add various stabilizers to reinforce the thermal stability.
For this purpose, known antioxidants (for example, hindered phenols), nitrogen-containing compounds (for example, melamine, urea, polyamides, etc.), alkali or alkaline earth metal compounds, etc. may be used alone or in combination of two or more. Is desirable. Further, the composition of the present invention can be colored in any color by appropriately adding various carbon blacks and various dyes and pigments. The combination of the weather resistance stabilizer according to the present invention is not only effective for imparting weather resistance to the resin material itself, but also extremely effective for fading and discoloration of various dyes and pigments added to the resin. It is extremely effective in maintaining the appearance quality of colored products. The combined use with carbon black has the effect of further improving weather resistance (light) stability. In order to impart desired properties to the composition of the present invention depending on its purpose, conventionally known additives such as lubricants,
It is also possible to add one or more kinds of nucleating agents, releasing agents, antistatic agents and other surfactants, or organic polymer materials, inorganic or organic fibrous, powdery or tabular fillers. Is. The composition of the present invention can be easily prepared by a known method generally used as a conventional resin composition preparation method. For example, after mixing the components, kneading and extruding with an extruder to prepare pellets, followed by a method of molding, once preparing pellets having a different composition, mixing a predetermined amount of the pellets and subjecting to molding Any method such as a method of obtaining a molded article having a composition or a method of directly charging one or more of each component into a molding machine can be used. It should be noted that each of these components can be added after being retained in an organic polymer or an inorganic substance, which is the retainer.

[0010]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. still,
The methods used to evaluate characteristic values such as weather resistance in the examples are as follows. 1) Crack generation time Test piece was measured with a weather meter [Suga Test Instruments Co., Ltd., WBL
-SUN-HCH type] after irradiation under a fade condition of 83 ° C., the presence or absence of cracks on the surface of the test piece was observed with a 10 times magnifying glass, and the time at which the cracks first occurred was defined as the time at which cracks occurred. The larger the value, the better the weather resistance. 2) Tensile Strength and Elongation Tensile strength and elongation were measured by a conventional method (ASTM-D638) for the test piece before irradiation with the above weather meter and after irradiation for a certain period of time. "Measurement impossible" means that the degree of deterioration of the test piece was remarkable and normal measurement could not be performed. 3) Changes in surface condition Changes in hue and gloss before and after irradiation were observed, and the degree of change was evaluated on a five-point scale. The smaller the number, the smaller the change, that is, the less gloss and the less discoloration. Examples 1 to 10 and Comparative Examples 1 to 23 Polyacetal resin [manufactured by Polyplastics Co., Ltd., trade name "DURACON (M90)"] was prepared by adding the weather resistance (light) stabilizer, fatty acid ester and hindered amine-based substance shown in Table 1. After adding and mixing with a Henschel mixer, it melt-kneaded using a 40 mm single screw extruder, and the pellet-shaped composition was prepared. Then, a test piece was molded from the pellet using an injection molding machine, and the weather resistance and other characteristics were measured and evaluated.
For comparison, as shown in Tables 2 and 3, the same preparation and evaluation were carried out in the case where the weather resistance stabilizer, the fatty acid ester and the hindered amine-based substance were not added, or in the case of any one component or only two components. These results are shown in Table 1, Table 2,
It shows in Table 3. As is clear from this result, the coexistence system of the weather resistance stabilizer, the fatty acid ester, and the hindered amine-based substance is
It can be seen that, as compared with a system in which these substances do not coexist or a system in which they do not exist, they have remarkable effects on crack generation time, reduction in tensile strength, surface state and the like.

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

[Table 3]

Note) Weather resistance stabilizer substance name A-12- [2'-hydroxy-3 ', 5'-di-t-
Amylphenyl] benzotriazole A-2 2-Hydroxy-4-oxybenzylbenzophenone fatty acid ester B-1 Polyethylene glycol monostearate ester, manufactured by NOF CORPORATION, Nonion S-40 (average degree of polymerization of polyethylene glycol 90) B- 2 Glycerin monostearate B-3 Ethylene glycol distearate B-4 Polyethylene glycol monostearate, NONION S-15.4 (average degree of polymerization of polyethylene glycol 35) manufactured by NOF CORPORATION B-5 Polyethylene glycol monostearate Acid ester, Nonion S-4 (average degree of polymerization of polyethylene glycol 9) manufactured by NOF CORPORATION Stabilizer C-1 bis (2,2,6,6-tetramethyl-4-piperidyl) adipate

Claims (5)

[Claims] 1. A polyacetal resin containing one or more weatherproof substances selected from the group consisting of (A) a benzotriazole-based substance, a benzophenone-based substance, an aromatic benzoate-based substance, a cyanoacrylate-based substance, and an oxalic acid anilide-based substance. A weather-resistant polyacetal resin composition comprising a light) stabilizer, (B) one or more fatty acid esters, and (C) one or more hindered amine substances. 2. The polyacetal resin composition according to claim 1, wherein the weather resistance (light) stabilizer is a benzotriazole-based substance. 3. The polyacetal resin composition according to claim 1, wherein the fatty acid ester is a fatty acid ester composed of a fatty acid having two or more carbon atoms and a polyhydric alcohol. 4. The polyacetal resin composition according to claim 1 or 2, wherein the fatty acid ester is a fatty acid ester comprising a fatty acid containing 2 or more carbon atoms and a polyalkylene glycol having an average degree of polymerization of 2 or more. 5. The polyacetal resin composition according to claim 1, wherein the fatty acid ester is a fatty acid ester comprising a fatty acid containing 12 or more carbon atoms and a polyalkylene glycol having an average degree of polymerization of 16 or more.