JP2009046549A - Polyacetal resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyacetal resin composition which can obtain a molded article such as a film and a fiber having excellent productivity and the inherent rigidity of polyacetal without utilizing alloying. <P>SOLUTION: The polyacetal resin composition comprises 100 pts.wt. polyacetal resin, 0.002-2.0 pts.wt. alkyl substituted triazine compound, and 0.01-5.0 pts.wt. hindered phenol compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a polyacetal resin comprising a polyacetal resin blended with an alkyl-substituted triazine compound and a hindered phenol compound, which has an excellent balance of mechanical properties, chemical resistance, slidability and the like, and is easy to process. It relates to a composition.

  Polyacetal resin has excellent balance of mechanical properties, chemical resistance, slidability, etc. and is easy to process, so it is a typical engineering plastic for electrical / electronic parts, automotive parts and other various machine parts. It is widely used as an injection molded product. However, since the crystallization speed is high, it is difficult to process into a film or fiber, and its use is limited.

  As a means for solving the above problems, alloying in which two or more kinds of polymers are mixed is performed. However, physical properties are often not improved by phase separation. In addition, even if film formation can be achieved by alloying, a large amount of the partner resin mixed with the polyacetal resin must be used, and the original mechanical properties of the polyacetal resin are impaired, resulting in a composition that takes advantage of the properties of the polyacetal resin. In that case, it is not practically preferable (see Patent Document 1).

JP 2003-113298 A

The present invention provides a polyacetal resin composition that solves the problems as described above, has excellent productivity, and can obtain a molded product such as a film or fiber that retains the original rigidity of polyacetal without using alloying. There is.

As a result of intensive studies to achieve the above object, the present inventors have found that the crystallization rate of the polyacetal resin is delayed by blending the alkyl-substituted triazine compound and the hindered phenol compound into the polyacetal resin. .

That is, this invention relates to the polyacetal resin composition which mix | blended 0.002-2.0 weight part of alkyl substituted triazine compounds, and 0.01-5.0 weight part of hindered phenolic compounds with respect to 100 weight part of polyacetal resin. Is.

According to the polyacetal resin composition of the present invention, it is possible to obtain molded articles such as films and fibers that have excellent productivity and retain the original rigidity of polyacetal without using alloying.

Hereinafter, the present invention will be described in detail.

The alkyl-substituted triazine compound used in the present invention is preferably an alkylated melamine compound represented by the following general formula (1) in which part or all of the amino group of melamine is alkylated. The amount of such an alkylated melamine compound is 0.002 to 2.0 parts by weight, preferably 0.003 to 1.5 parts by weight, more preferably 0.005 to 1.0 parts by weight, based on the polyacetal resin. It is. When the compounding amount of the alkylated melamine compound is less than 0.002 parts by weight, the thermal stability is deteriorated. Conversely, when the amount of the alkylated melamine compound added is more than 2.0 parts by weight, the crystallization rate is reversed. In addition to being faster, it also causes mold contamination problems in films, fiber surface appearance and injection molded products.

（式中、Ｒ^１〜Ｒ^６は各々独立にＨ,炭素数１〜４のアルキル基又は−ＣＨ_２ＯＲ^７であり、Ｒ^７はＨ, 炭素数１〜４のアルキル基又は−Ｒ^８ＣＯＯＲ^９であり、Ｒ^８は−（ＣＨ₂）ｎ−（ｎ＝１〜４の整数）であり、Ｒ^９はで炭素数１〜４のアルキル基である）

(Wherein R ^{1 to} R ⁶ are each independently H, an alkyl group having 1 to 4 carbon atoms, or —CH ₂ OR ⁷ , and R ⁷ is H, an alkyl group having 1 to 4 carbon atoms, or —R ⁸ COOR ⁹ and R ⁸ is — (CH ₂ ) n — (n is an integer of 1 to 4), and R ⁹ is an alkyl group having 1 to 4 carbon atoms.

The alkylated melamine compound used in the present invention includes, for example, R ^{1 to} R ⁶ = —CH ₂ OCH ₃ (complete alkyl group type), R ¹ , R ³ , R ⁵ = —CH ₂ OCH ₃ in the general formula (1), ^{R 2, R 4, R 6} = H ( imino group ^{type), R 1, R 3,} R 5 = -CH 2 OCH 3, R 2, R 4, R 6 = -CH 2 OH ( methylol group-type), The complete alkyl group type and the imino group type are preferable, and the complete alkyl group type hexamethoxymethylmelamine is most preferable.

  Examples of the hindered phenol compound used in the present invention include 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis-3- ( 3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, pentaerythrityl-tetrakis-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis ( 6-t-butyl-4-methylphenol), 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl] propionyloxy) -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane, N, N'-hexane-1,6-diylbis [3- (3,5-di- - butyl-4-hydroxyphenyl) propionamide], 3,5-bis (1,1-dimethylethyl) -4-hindered phenols such as hydroxy benzenepropanoic acid 1,6-hexanediyl ester. These may be used alone or in combination of two or more.

The amount of these hindered phenol compounds is preferably 0.01 to 5.0 parts by weight, more preferably 0.02 to 2.0 parts by weight, and still more preferably 0.1 to 100 parts by weight of the polyacetal resin. 1.0 part by weight.

The polyacetal resin in the present invention may be a so-called polyacetal homopolymer obtained by homopolymerization of formaldehyde or a polyacetal copolymer obtained by polymerization of trioxane and a cyclic ether and / or a cyclic formal compound.

Examples of the cyclic ether and / or cyclic formal compound copolymerizable with trioxane used in the present invention include 1,3-dioxolane, 2-ethyl-1,3-dioxolane, 2-propyl-1,3-dioxolane, 2- Butyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 2-phenyl-2-methyl-1,3-dioxolane, 4-methyl-1,3-dioxolane, 2,4-dimethyl- 1,3-dioxolane, 2-ethyl-4-methyl-1,3-dioxolane, 4,4-dimethyl-1,3-dioxolane, 4,5-dimethyl-1,3-dioxolane, 2,2,4- Trimethyl-1,3-dioxolane, 4-hydroxymethyl-1,3-dioxolane, 4-butyloxymethyl-1,3-dioxolane, 4-phenoxymethyl- , 3-dioxolane, 4-chloromethyl-1,3-dioxolane, 1,3 Jiokikabishikuro [3,4,0] nonane and the like, also 1,3-dioxolane are preferred among these.

The cyclic ether and / or cyclic formal compound copolymerizable with trioxane used in the present invention is 0.5 to 30 parts by weight, preferably 0.75 to 0.25 parts by weight, more preferably, per 1 mole of trioxane. Is 1.0 to 20 parts by weight. When the amount of the cyclic ether and / or cyclic formal compound used is larger than this, the polymerization yield is lowered, and when it is small, the effects on the thermal stability, toughness and impact resistance are remarkably lowered.

As the polymerization catalyst of the present invention, a general cationically active catalyst is used. Such cationically active catalysts include Lewis acids, especially halides such as boron, tin, titanium, phosphorus, arsenic and antimony such as boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentachloride, pentafluoride. Compounds such as phosphorus phosphide, arsenic pentafluoride and antimony pentafluoride, and complex compounds or salts thereof, protic acids such as trifluoromethanesulfonic acid, perchloric acid, esters of protic acids, especially perchloric acid and lower aliphatic alcohols Esters, protonic acid anhydrides, especially mixed anhydrides of perchloric acid and lower aliphatic carboxylic acids, or triethyloxonium hexafluorophosphate, triphenylmethylhexafluoroarsenate, acetylhexafluoroborate, heteropolyacid Or its acid salt, isopolyacid or its Such as gender salts. In particular, a compound containing boron trifluoride, or boron trifluoride hydrate and a coordination complex compound are suitable, and boron trifluoride diethyl etherate, trifluoride which is a coordination complex with ethers. Boron dibutyl etherate is particularly preferred.

The amount of the catalyst used is 1 × 10 ⁻⁷ to 1 × 10 ⁻³ mol, preferably 1 × 10 ⁻⁷ to 1 × 10 ⁻⁴ mol, relative to 1 mol of trioxane. In the present invention, usually, when the polymerization yield reaches 90% or more, preferably 95% or more, more preferably 97% or more, the catalyst is deactivated and the polymerization is stopped.

The polymerization method of the polyacetal resin can be performed by the same equipment and method as those of conventionally known trioxane copolymerization. That is, it can be either batch type or continuous type, and can also be applied to bulk polymerization and polymerization methods performed in the presence of an organic solvent such as cyclohexane. A batch type reactor can be used with a stirrer, and in continuous bulk polymerization, rapid solidification during polymerization, powerful stirring ability to cope with heat generation, precise temperature control, and prevention of scale adhesion Such devices as a kneader equipped with a self-cleaning function, a twin-screw continuous extrusion kneader, and a twin-screw paddle type continuous mixer are preferably used.

In the polymerization, a low molecular weight acetal compound is generally used to adjust the molecular weight. Examples of the acetal compound include, but are not limited to, methylal, methoxymethylal, dimethoxymethylal, trimethoxymethylal, oxymethylene di-n-butyl ether, and the like. Usually, methylal is preferably used. In general, such an acetal compound is used by adjusting the addition amount in the range of 0 to 1% by weight with respect to the monomer according to the target molecular weight.

The polyacetal copolymer obtained by the polymerization reaction uses a trivalent organic phosphorus compound, an amine compound, a quencher such as an alkali metal or alkaline earth metal hydroxide alone or in the form of an aqueous solution or an organic solution. The catalyst is deactivated and removed by a known method. Of these, trivalent organic phosphorus compounds, tertiary amines, and hindered amines are particularly preferable.

In order to give the polyacetal copolymer of the present invention desired properties according to its purpose, various conventionally known heat stabilizers, weather resistance (light stabilizers), coloring agents such as lubricants, dyes and pigments, and release agents described later. It is preferable to add additives such as an agent, an antistatic agent, a flame retardant, a fluorescent brightening agent, and a filler.

Heat stabilizers include alkylated triazines as well as melamine, guanamine, benzoguanamine, cyanoguanidine, N, N-diarylmelamine, melamine-formaldehyde condensate, urea, heated heat condensate synthesized from urea, polyacrylamine Further, nitrogen-containing compounds such as polyethyleneimine, polyacrylamide, polyamide, urethane compound and pyridine compound may be used in combination. Among these, melamine and melamine-formaldehyde condensates are more preferable.

The addition amount of these nitrogen-containing compounds is preferably 5 to 30% by weight and more preferably 10 to 20% by weight with respect to 100% by weight of the alkylated melamine compound.

In addition, it is preferable to mix a metal-containing compound represented by a group consisting of an alkali metal or alkaline earth metal hydroxide, an inorganic acid salt, or an alkoxide as a heat stabilizer, such as sodium, potassium, calcium, magnesium, barium. And hydroxides, inorganic acid salts, alkoxides, and the like. Among these, calcium hydroxide, magnesium hydroxide, potassium hydroxide, calcium carbonate, and magnesium carbonate are most preferable. These may be used alone or in combination of two or more.

The amount of the metal-containing compound represented by the group consisting of the alkali metal or alkaline earth metal hydroxide, inorganic acid salt, or alkoxide is 0.001 to 5 with respect to 100% by weight of the polyacetal polymer. 0.0 wt% is preferable, and 0.001 to 1.0 wt% is more preferable.

In the present invention, hindered amine compounds, benzophenone compounds, benzotriazole compounds, aromatic benzoate compounds, cyanoacrylate compounds, oxalic acid anilide compounds, and the like may be added as weathering (light stabilizer) agents. The addition amount of these weathering agents is preferably 0.01 to 5% by weight and more preferably 0.01 to 3% by weight with respect to 100% by weight of the polyacetal copolymer.

A metal salt of a higher fatty acid may be added to the polyacetal copolymer of the present invention as a lubricant and a heat stabilizer. Although the metal salt of a higher fatty acid is not particularly limited, magnesium salts, calcium salts, barium salts, and the like of higher fatty acids such as lauric acid, palmitic acid, stearic acid, behenic acid, and 12-hydroxystearic acid are preferable.
Moreover, 0.0001-5 weight% is preferable with respect to a polyacetal polymer, and, as for the addition amount of the metal salt of these higher fatty acids, 0.0001-3 weight% is more preferable.

Moreover, it is preferable to mix | blend the higher fatty acid amide which has a C10 or more long chain, the fatty acid ester of a polyhydric alcohol, and paraffin wax as a mold release agent. The higher fatty acid amide having a long chain having 10 or more carbon atoms is not particularly limited, but examples thereof include stearic acid amide, ethylene bisstearamide, methylene bisstearamide, methylene bislauramide, palmitic acid amide, and oleic acid amide. be able to. Among these, ethylene bisstearamide, methylene bisstearamide, and methylene bislauramide are more preferable. Specific examples of fatty acid esters of polyhydric alcohols include polyhydric alcohols such as glycerin, diglycerin, pentaerythritol, sorbitan, ethylene glycol, diethylene glycol, trimethylolmethane, trimethylolethane, behenic acid, serotic acid, and montanic acid. And fatty acid esters such as laccellic acid and the like, and paraffin wax having a molecular weight of 1,000 to 2,000,000 is preferable. These may be used alone or in combination of two or more.

The addition amount of the paraffin wax, the higher fatty acid amide having a long chain having 10 or more carbon atoms and the fatty acid ester of polyhydric alcohol is preferably 0.01 to 5% by weight with respect to 100% by weight of the polyacetal polymer. -3 wt% is more preferred.

You may add a coumarin type | system | group fluorescent whitening agent and a benzoxazole type | system | group fluorescent whitening agent as a fluorescent whitening agent with respect to the polyacetal copolymer of this invention. The coumarin fluorescent whitening agent and the benzoxazole fluorescent whitening agent are not particularly limited, but 3- (4′-acetylaminophenyl) -7-acetylaminocoumarin, 3- (4′-carboxyphenyl) -4-methyl. -7-diethylaminocoumarin, 2,5-bis (5′-t-butylbenzoxazol-2′-yl) thiophene, 2,5-bis [5′-t-butylbenzoxazolyl (2)] Thiophene is preferred. The addition amount of these coumarin fluorescent brighteners and benzoxazole fluorescent brighteners is preferably 0.001 to 500 ppm, more preferably 0.01 to 100 ppm, based on the polyacetal polymer.

  Glass beads, mica, kaolin, silicon dioxide, clay, asbestos, silica, diatomaceous earth, graphite, molybdenum disulfide, carbon black, titanium oxide, glass fiber, milled fiber, potassium titanate fiber, boron fiber as fillers Carbon fiber, aramid fiber or the like may be added. The amount of these fillers is preferably 0.01 to 200% by weight and more preferably 0.1 to 100% by weight with respect to 100% by weight of the polyacetal polymer.

The melt flow index (MI) value (190 ° C., load 2,160 g) of the polyacetal copolymer according to the present invention is usually 0.5 to 100 g / 10 min, preferably 1.0 to 70 g / 10 min.

The polyacetal copolymer which has deactivated the polymerization catalyst can be sent to the subsequent stabilization step as it is, but if further purification is required, washing, separation and recovery of unreacted monomers, drying, etc. Can pass.

In the present invention, these various stabilizers and additives are mixed with the polyacetal polymer in which the polymerization catalyst has been deactivated, and heated and melt-kneaded by a single-screw or twin-screw extruder, a twin-screw paddle type continuous mixer, or the like. Heat-stabilized. At this time, some of these various stabilizers or additives may be added separately after the thermal stabilization treatment, and water, alcohol, amine, etc. may be added during the thermal stabilization. .

The method of blending and mixing these various stabilizers and additives with the polyacetal polymer that has deactivated the polymerization catalyst is not particularly limited, and any method that can be used industrially may be used. For example, after mixing each component with a blender such as a turnbull mixer or a Henschel mixer, a method of kneading with a single screw or twin screw extruder, a twin screw paddle type continuous mixer, a bumper mixer, a roll or the like is appropriately selected. . Each component is preferably dried before kneading.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this method is not limited to this. The evaluation was performed by the following method.
[Crystallizing time]
The polyacetal resin composition pellets sandwiched between cover glasses (18 mm × 18 mm × 0.12 to 0.17 mm) were melted with a hot plate at 200 ° C. and formed into a film (thickness: 0.1 to 0.2 mm) while being crushed with tweezers. This was put into a 200 ° C. air bath using a polymer crystallization rate measuring apparatus (MK-701, manufactured by Kotaki Seisakusho Co., Ltd.) to melt the film-like polyacetal resin composition. After 3 minutes, the melted polyacetal resin composition was dropped together with the cover glass onto a measurement optical path in an oil bath at 150 ° C. (After this, the amount of light after transmission decreased as the polyacetal resin composition crystallized. The brightness of the light source lamp increases to keep the light intensity constant). The recorder started when the polyacetal resin composition film was dropped, and then the increasing luminance was converted into a voltage and increased similarly, and converged when crystallization was completed. The time from when the sample was put into the oil bath to ½ of the amount of voltage change until crystallization was completed was calculated and defined as ½ crystallization time.
[Film appearance]
A polyacetal film was obtained using a T-die film molding machine in which a T-die was installed in the head of a single-screw extruder using the resin compositions obtained in Examples or Comparative Examples as materials. T-die cast film molding was performed under the following conditions.
Extruder: Ikegai FS40-25
Screw diameter: 40mmφ, L / D = 25
Screw shape: Full flight screw Screw rotation speed: 80rpm
Compression ratio: 3.5, 6 crest compression type
T die: 600 mm wide coat hanger die made by Musashino Machine Co., Ltd. Die lip opening = 0.4 mm
Cylinder temperature: 190-220 ° C
Die temperature: 190 ° C
Cast roll temperature: 100 ° C
The film thickness of the film molded product obtained by the above method is 80 μm, and the film appearance is described in the examples based on the following criteria.

<Example 1>
100 parts by weight of trioxane and 13 parts by weight of 1,3-dioxolane and benzene solution of boron trifluoride diethyl etherate as a catalyst in a biaxial continuous polymerization machine having a self-cleaning paddle with a jacket set at a temperature of 65 ° C. Was continuously added so that 0.06 mmol per 1 mol of all monomers and methylal as a molecular weight regulator were 200 ppm as benzene solution with respect to all monomers, and the residence time was 25 minutes. .
Triphenylphosphine is added to the resulting polymer as a benzene solution so as to be 2 mol with respect to 1 mol of boron trifluoride diethyl etherate used. After deactivation of the catalyst, it is pulverized to obtain a polyacetal polymer. Obtained. The polymer yield was 95% and the melt index (MI) was 8.5 g / 10 min.
Next, 100 parts by weight of the obtained polyacetal polymer, 0.3 parts by weight of triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], fully alkylated melamine CYMEL 303 (Compound which is R ^{1 to} R ⁶ = —CH ₂ OCH ₃ in the general formula (1) manufactured by CYTEC) After stirring 0.05 parts by weight with a Henschel mixer for 3 minutes, the same-direction twin-screw extruder (Nippon Steel Works) Manufactured at an inner diameter of 69 mm, L / D = 31.5) at a rate of 60 kg / hour, melted at 220 ° C. as a reduced pressure of 20 kPa at the vent, and continuously biaxial surface renewal type horizontal kneader (effective internal volume) 60L: the volume of the total internal volume excluding the volume occupied by the stirring blade). Adjusting the liquid level so that the residence time of the biaxial surface renewal type horizontal kneader is 25 minutes, and performing the vacuum devolatilization at 220 ° C. under a reduced pressure of 20 kPa, the polyacetal resin composition is continuously extracted with a gear pump. I got a thing.

<Examples 2-5, Comparative Examples 1-3>
A polyacetal resin composition having the composition shown in Table 1 was obtained according to the above method.

Claims (6)

A polyacetal resin composition comprising 0.002 to 2.0 parts by weight of an alkyl-substituted triazine compound and 0.01 to 5.0 parts by weight of a hindered phenol compound based on 100 parts by weight of a polyacetal resin. The polyacetal resin composition according to claim 1, wherein the alkyl-substituted triazine compound is an alkylated melamine compound. The polyacetal resin composition according to claim 1, wherein the alkyl-substituted triazine compound is hexamethoxymethylmelamine. The polyacetal resin composition according to any one of claims 1 to 3, wherein the hindered phenol compound is triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate]. The fiber manufactured from the polyacetal resin composition in any one of Claims 1-4. The film manufactured from the polyacetal resin composition in any one of Claims 1-4.