JP5008256B2 - Method for producing polyoxymethylene resin composition - Google Patents

Description

The present invention relates to a method for producing a polyoxymethylene resin composition excellent in formaldehyde odor or mold deposit is extremely small thermal stability during molding, and a process for producing a superior polyoxymethylene resin composition color .

  Polyoxymethylene resins are known as engineering plastics that balance mechanical strength and impact resistance, and are used in a wide range of fields as electronic device parts and automobile parts. However, polyoxymethylene resins are structurally poor in thermal stability, and formaldehyde gas is generated during molding, deteriorating the working environment, and adhesion of oligomers generated on molds commonly referred to as mold deposits. There are several points that should be improved, such as deteriorating the appearance.

  In order to meet such demands, various stabilizer formulations have been conventionally devised as methods for improving the defects of polyoxymethylene resins. For example, the following six examples are known.

(1) Stable against oxidation and thermal decomposition by including polyoxymethylene resin with sterically hindered phenol and alkaline earth metal salt of C10-20 fatty acid and / or hydroxide of alkaline earth metal Polyoxymethylene resin composition (see, for example, Patent Document 1).
(2) A polyoxymethylene resin containing a sterically hindered phenol and an alkaline earth metal salt of a fatty acid having 22 to 36 carbon atoms, which is stabilized against oxidation and thermal decomposition, and whose discoloration is remarkably suppressed. An oxymethylene resin composition (see, for example, Patent Document 2).
(3) The group consisting of polyoxymethylene resin, polyamide, fatty acid having 12 to 35 carbon atoms, calcium salt of fatty acid having 12 to 35 carbon atoms, calcium of aliphatic alcohol having 12 to 36 carbon atoms, or magnesium salt By containing at least one, a polyoxymethylene resin composition having very little precipitate on the mold during molding and excellent thermal stability (for example, see Patent Document 3).
(4) Extremely high thermal stability can be achieved by including polyoxymethylene resin with amine-substituted triazine compound, sterically hindered phenol, alkali metal or alkaline earth metal hydroxide, inorganic acid salt, carboxylate or alkoxide. A polyoxymethylene resin composition (see, for example, Patent Document 4).
(5) A polyoxymethylene resin comprising a fatty acid ester of a polyhydric alcohol derived from a polyhydric alcohol having 2 to 10 carbon atoms and a higher fatty acid having 22 to 32 carbon atoms, and a fatty acid having 12 to 35 carbon atoms. A polyoxymethylene resin composition that is excellent in thermal stability by containing an alkaline earth metal salt, has little discoloration during molding, and has very little deposit on the mold (see, for example, Patent Document 5).
(6) A polyoxymethylene resin, a sterically hindered phenol, an amine-substituted triazine compound, a metal-containing compound represented by the group consisting of an alkali metal or alkaline earth metal hydroxide, an inorganic acid salt, and an alkoxide, and carbon. A fatty acid ester of a polyhydric alcohol derived from an alkali metal salt or alkaline earth metal salt of a fatty acid of several 10 to 36, a polyhydric alcohol having 2 to 10 carbon atoms and a higher fatty acid having 10 to 32 carbon atoms; Including a higher fatty acid amide having a long chain having 10 or more carbon atoms, it exhibits thermal stability not achieved by conventional combinations, and is particularly excellent when blended with color pigments typified by carbon black and titanium oxide. A polyoxymethylene resin composition exhibiting thermal stability (see, for example, Patent Document 6).

  However, in any of the above publications, reduction of formaldehyde odor and mold deposit at the time of molding is still not sufficient, and thermal stability is also insufficient. According to the study by the present inventors, a metal compound such as a fatty acid metal salt reacts with formic acid in the polyoxymethylene resin to produce a formic acid metal salt. It was found that by-product fatty acids may impair the thermal stability of the polyoxymethylene resin.

  Moreover, the following example is known as an improvement technique by mix | blending the carboxylic acid compound characterized by having a hydroxyl group with polyoxymethylene resin.

  By incorporating 0.001 to 3 parts by weight of a carboxylic acid compound having 3 to 200 parts by weight of a glass-based inorganic filler and a hydroxyl group with respect to 100 parts by weight of the polyoxymethylene resin, the glass-based inorganic A polyoxymethylene resin composition that further improves the mechanical properties of a polyoxymethylene resin material containing a filler (see, for example, Patent Document 7).

  However, the resin composition described in Patent Document 7 has excellent mechanical properties by preparing a composition by melting and kneading a carboxylic acid compound having a hydroxyl group together with a polyoxymethylene resin and a glass-based inorganic filler. The purpose is to obtain a reinforced polyoxymethylene resin composition, and the document does not mention any formaldehyde odor, mold deposit and thermal stability at the time of molding. Patent Document 7 only discloses a carboxylic acid having a hydroxyl group, and even when such a compound is added to the polyoxymethylene resin, the thermal stability cannot be improved.

Japanese Patent Publication No.55-22508 Japanese Patent Publication No. 60-56748 Japanese Patent Publication No.62-4422 Japanese Examined Patent Publication No. 62-58387 JP-A-4-63857 JP 7-173368 A JP 2002-371168 A

An object of the present invention is to provide a method for producing a polyoxymethylene resin composition having excellent thermal stability and color tone that can withstand high temperature and long-term continuous molding.

（ただし、式中Ｒ ³ は水素原子または炭素数１〜３０の１価の有機残基を表わす。Ｒ ⁴ 〜Ｒ ⁷ はそれぞれ炭素数１〜５のアルキル基を表わし、それぞれ同一であっても異なっていてもよい。ｐは１以上の整数を表わし、Ｒ ⁸ はｐ価の有機残基を表わす。） The process for producing a polyoxymethylene resin composition of the present invention that achieves the above object comprises a mixture of trioxane and a cyclic ether, boron trifluoride, boron trifluoride hydrate, boron trifluoride and oxygen atom or sulfur atom. In the production of an oxymethylene homopolymer by homopolymerizing an oxymethylene unit in the presence of at least one polymerization catalyst selected from the group consisting of coordination compounds with organic compounds containing When an oxymethylene copolymer is produced by copolymerizing the oxyalkylene unit, the polymerization catalyst is used as a hindered amine compound (L) having a molecular weight of 400 or more represented by the following general formula (II) after completion of the polymerization. by adding 0.01 to 10 parts by weight of the crude polymer 100 parts by weight of the polyoxymethylene resin (a), the The crude polymer 100 parts by weight of the polyoxymethylene resin obtained by active (A), tripotassium citrate (B) was added 0.001 parts by weight of a mixture obtained by mixing with water, 100 to 260 ° C. It is characterized by heating in the temperature range.

(However, in the formula, R ³ represents a hydrogen atom or a monovalent organic residue having 1 to 30 carbon atoms. R ^{4 to} R ⁷ each represents an alkyl group having 1 to 5 carbon atoms. ( P represents an integer of 1 or more, and R ⁸ represents a p-valent organic residue.)

Method for producing a polyoxymethylene resin composition of the present invention, by adding various compounding agents as required, mixing is for kneading.

According to the production method of the present invention, as described below, it is possible to prevent a decrease in thermal stability of the polyoxymethylene resin, which is excellent in thermal stability in a high-temperature molten state, and formaldehyde odor during long-term continuous molding. And a polyoxymethylene resin composition having excellent mechanical strength and color tone can be obtained.

The polyoxymethylene resin (A) used in the production method of the present invention comprises an oxymethylene homopolymer and / or mainly an oxymethylene unit, and at least one oxymethylene having 2 to 8 carbon atoms in the polymer main chain. It is an oxymethylene copolymer containing an alkylene unit. The polyoxymethylene resin (A) is preferably an oxymethylene copolymer from the viewpoint of a balance between heat resistance, mechanical strength, and impact characteristics.

  The oxymethylene homopolymer is a polymer composed of oxymethylene units and having both ends of the polymer blocked with ester or ether groups. For example, a substantially 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 filtered off. An oxymethylene homopolymer can be prepared by heating in the presence of sodium acetate in acetic anhydride to acetylate the terminal.

An oxymethylene-based copolymer is a polymer in which oxyalkylene monomer units are randomly inserted into a polymer chain composed of oxymethylene monomer units and both ends of the polymer are blocked with ester or ether groups. For example, a substantially anhydrous trioxane or a cyclic oligomer of formaldehyde such as tetraoxane and ethylene oxide, propylene oxide, 1,3-dioxolane, 1,3-propanediol formal, 1,4-butanediol formal, 1,5 A cyclic ether having an oxyalkylene unit having 2 or more carbon atoms in the molecule such as pentanediol formal, 1,6-hexanediol formal, diethylene glycol formal, 1,3,5-trioxepane, 1,3,6-trioxocane By dissolving or suspending in an organic solvent such as cyclohexane or benzene, polymerizing by adding a Lewis acid catalyst such as boron trifluoride or diethyl etherate, and decomposing and removing unstable terminals Stabilize (stabilization process) It can be prepared oxymethylene copolymer. Alternatively, an oxymethylene copolymer can be prepared by introducing bulk polymerization into a self-cleaning stirrer without introducing any solvent and introducing a premixed mixture of a copolymer component and a catalyst. . If desired, the polymerized catalyst can be removed from the polymer by washing, or the polymerized catalyst can be deactivated with a deactivator, and then the unstable terminal can be decomposed and removed for stabilization. The deactivator of the polymerization catalyst is added hindered amine compound represented by the molecular weight of 400 or more single general formula (II). Bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate is particularly preferable.

  The content of the oxyalkylene comonomer unit in the oxymethylene-based copolymer is 0.1 to 10 mol, preferably 0.1 to 7 mol, more preferably 0.1 to 5 mol, per 100 mol of the oxymethylene monomer unit. Selected by range. From the viewpoint of thermal stability of the oxymethylene-based copolymer and suppression of deterioration in appearance due to deterioration during molding, the content of the oxyalkylene comonomer unit is preferably not less than the above lower limit, which improves the crystallinity during molding. From the viewpoint, the content of the oxyalkylene comonomer unit is preferably not more than the above upper limit.

  A particularly preferred polyoxymethylene resin (A) is a method described in JP-A No. 62-257922, for example, trioxane and a cyclic ether or a cyclic formal, and a Lewis acid catalyst such as boron trifluoride / diethyl etherate. In the presence of bulk polymerization, the polymer is stabilized by adding a hindered amine compound represented by the general formula (II) to stop the polymerization reaction and further decomposing and removing unstable terminals.

（ただし、式中Ｒ^３は水素原子または炭素数１〜３０の１価の有機残基を表わす。Ｒ^４〜Ｒ^７はそれぞれ炭素数１〜５のアルキル基を表わし、それぞれ同一であっても異なっていてもよい。ｐは１以上の整数を表わし、Ｒ^８はｐ価の有機残基を表わす。）

(In the formula, R ³ represents a hydrogen atom or a monovalent organic residue having 1 to 30 carbon atoms. R ^{4 to} R ⁷ each represents an alkyl group having 1 to 5 carbon atoms, and each may be the same) (P represents an integer of 1 or more, and R ⁸ represents a p-valent organic residue.)

The composition of the resin composition produced in the present invention represents the amount of other components added in parts by weight with respect to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). The polyoxymethylene resin (A) is a crude polymer of a polyoxymethylene polymer that has been polymerized by the above-described polymerization method and has been subjected to catalyst deactivation treatment and / or stabilization treatment.

The method for producing the resin composition of the present invention is a metal salt of carboxylic acid with respect to 100 parts by weight of the crude polymer of polyoxymethylene resin (A) , and reacts with formic acid to form carboxylic acid, By adding 0.001 to 10 parts by weight of tripotassium citrate (B), the carboxylic acid has the property of (i) condensation polymerization and / or (ii) self-condensation to cyclize, the thermal stability This is a significant improvement.

For stabilization of polyoxymethylene resin, when metal salt of carboxylic acid such as fatty acid metal salt is added, formic acid in polyoxymethylene resin reacts to form formic acid metal salt, resulting in deterioration of physical properties due to formic acid. Is suppressed. However, it became clear that the carboxylic acid by-produced at the same time may impair the thermal stability of the polyoxymethylene resin. Therefore, when the carboxylic acid is by-produced, the carboxylic acid acts on the polyoxymethylene resin by giving the carboxylic acid the property of (i) polycondensation and / or (ii) self-condensation and cyclization. It was clarified that the thermal stability is prevented from being lowered. Lipoic Rio Kishime Chin Ren resin composition by the this, the thermal stability is remarkably improved, the color tone is good, and those formaldehyde odor and mold deposit of generation during continuous molding has a very little superior characteristics is there.

Tripotassium citrate (B) is used in the method for producing the polyoxymethylene resin composition of the present invention . Citric acid constituting tripotassium citrate (B 2 ) tends to exhibit the property of polycondensation or self-condensation and cyclization.

Oite the method for producing the resin composition of the present invention, the use of citric acid tripotassium can decrease the mechanical properties without obtaining excellent polyoxymethylene resin color and thermal stability.

In the present invention, the amount of tripotassium citrate (B) added is 0.001 to 10 parts by weight, preferably 0.01 to 2 parts by weight, based on 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). Particularly preferred is 0.03 to 1 part by weight. If it is less than 0.001 part by weight, the improvement of the thermal stability is insufficient, and if it exceeds 10 parts by weight, the polyoxymethylene resin is decomposed and foamed, and the stability is impaired.

In the production method of the present invention, 0.1 to 20 parts by weight of the slidability improver (C) may be added to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A).

Sliding property improving agent used in this onset bright (C), if a polymer which can impart slidability to the polyoxymethylene resin composition is not particularly limited, polyethylene, polypropylene, ethylene / alpha- Olefin copolymers, and olefin polymers such as graft modified products thereof, silicone polymers such as polydimethylsiloxane, fluorine polymers such as polytetrafluoroethylene and polyvinylidene fluoride, polyethylene glycol, polypropylene glycol, etc. It can preferably be selected from ether polymers. Here, the polymer preferably has a number average molecular weight of 1000 or more, more preferably 5000 or more, in order to suppress mechanical properties and bleed out.

  Preferable examples of the slidability improver (C) include olefin polymers. Olefin polymers include olefin homopolymers, olefin copolymers, vinyl or ether polymer graft copolymers based on these, olefin monomers, acrylic monomers, and the like. And a copolymer with a monomer or a methacrylic monomer.

  Specific examples of the olefin homopolymer include high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polybutene, and the like.

  Examples of olefin copolymers include ethylene / propylene copolymers, ethylene / butene copolymers, ethylene / octene copolymers, and the like. These olefin polymers can be polymerized by a multi-site catalyst represented by a known Ziegler catalyst and a single site catalyst represented by a metallocene catalyst. Ultra high molecular weight polyethylene, crosslinked polyolefin particles, and the like can also be used.

  As the olefin-based graft copolymer, a graft copolymer in which one or two or more of an olefin-based polymer and a vinyl-based polymer or an ether-based polymer are chemically bonded in a branched or crosslinked structure is preferably used. Can do. This graft copolymer has the olefin polymer as a main chain component and is grafted with one or more of the following vinyl or ether polymers. For example, as a vinyl polymer, polymethyl methacrylate, polyethyl acrylate, polybutyl acrylate, 2-ethylhexyl polyacrylate, polystyrene, polyacrylonitrile, acrylonitrile / styrene copolymer, butyl acrylate / methyl methacrylate copolymer And a butyl acrylate / styrene copolymer. Examples of the ether polymer include polyethylene glycol and its alkyl ether or ester, polytrimethylene glycol, polypropylene glycol, polytetramethylene glycol and the like. Specific examples of the graft copolymer preferably used in the present invention include polyethylene-g-acrylonitrile styrene copolymer (“-g-” represents graft copolymerization), polyethylene-g-polymethyl methacrylate, and the like. It is done.

  The method for producing the graft copolymer is not particularly limited, but can be prepared by a generally well-known radical reaction. For example, a method of adding a radical catalyst to a monomer of an olefin polymer and a vinyl or ether polymer and melt-kneading and grafting, or an olefin polymer, a vinyl polymer or an ether polymer may be used. Examples include a method of adding an oxide or the like to generate free radicals and melt-kneading them with other components.

  The olefin copolymer is also preferably a copolymer of an olefin monomer and one or more of acrylic monomers or methacrylic monomers. Acrylic monomers include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc., and methacrylic monomers include methacrylic acid, methyl methacrylate, ethyl methacrylate. , Butyl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate and the like. Examples of preferred copolymers include ethylene / ethyl acrylate copolymers, ethylene / glycidyl methacrylate copolymers, ethylene / methacrylic acid / glycidyl methacrylate copolymers, and the like.

Another preferred example of the slidability improver (C) used in the method for producing the resin composition of the present invention is one or two selected from a silicone polymer and a fluorine polymer. Examples of the silicone polymer include polyorganosiloxanes such as polydimethylsiloxane and polydiethylsiloxane, and modified polyorganosiloxanes obtained by modifying them with an acrylic polymer or a methacrylic polymer can also be used. Examples of the fluoropolymer include polytetrafluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride.

The slidability improver (C) used in the present invention is preferably 0.1 to 20 parts by weight, more preferably 1 to 15 parts by weight with respect to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). Added. If the added amount is less than 0.1 parts by weight, the effect of improving the friction and wear characteristics by the slidability improver (C) is not sufficient, and if it is more than 20 parts by weight, the effect of improving the friction and wear characteristics decreases, and mechanical characteristics are reduced. In particular, it tends to cause deterioration of the surface appearance which is mechanical strength at high temperature and molding processability.

Furthermore, in the method for producing the resin composition of the present invention, 1 to 10 parts by weight of conductive carbon black (D) may be added to 100 parts by weight of the crude polymer of polyoxymethylene resin (A).

The conductive carbon black (D) preferably used in the production method of the present invention has a dibutyl phthalate oil absorption (hereinafter abbreviated as DBP oil absorption) of preferably 130 ml / 100 g or more, more preferably 150 ml / 100 g or more, It is preferably 200 ml / 100 g or more, particularly preferably 300 ml / 100 g or more. Although there is no restriction | limiting in particular in the upper limit of DBP oil absorption, The higher is better, but the conductive carbon black which can be obtained from a normal market is about 750 ml / 100g or less.

  The DBP oil absorption amount is a scale indicating the degree of carbon black structure development, and the DBP oil absorption amount increases and the conductivity increases as the structure develops. The DBP oil absorption can be determined by titration according to the structure index of ASTM D2415-65T.

  As the conductive carbon black (D), one having a preferable DBP oil absorption amount can be appropriately selected from commercially available ones. Examples of such commercially available products include “Ketjen Black” EC (DBP oil absorption 380 ml / 100 g, manufactured by Lion Akzo), “Ketjen Black” EC600DJ (DBP oil absorption 495 ml / 100 g, manufactured by Lion Akzo) ), “Blintex” XE2 (DBP oil absorption 370 ml / 100 g, manufactured by Degussa), “Mitsubishi Carbon Black” # 3050 (DBP oil absorption 175 ml / 100 g, manufactured by Mitsubishi Chemical), and the like.

The amount of conductive carbon black (D) used in the present invention is preferably 1 to 10 parts by weight, more preferably 3 to 7 parts per 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). Parts by weight. When the amount of the conductive carbon black (D) added is less than 1 part by weight, sufficient conductivity is not exhibited, and when it is more than 10 parts by weight, the fluidity of the resin composition is remarkably lowered, which is not preferable.

In the method for producing a polyoxymethylene resin composition of the present invention, carbon fiber (E) and / or polyamide elastomer (F) may be further added. In addition it is possible to express a higher conductivity by the addition of carbon fibers (E) and / or polyamide elastomer (F) a conductive carbon black (D), the thermal stability of Po Li oxymethylene resin composition It is more preferable because high conductivity can be expressed without impairing the resistance.

The carbon fiber (E) used in the production method of the present invention is preferably a PAN-based, pitch-based or rayon-based carbon fiber, and more preferably a PAN-based carbon fiber having an excellent balance of strength, elastic modulus, price and the like. It is also possible to use metal-coated carbon fibers obtained by coating carbon fibers with metals such as nickel and copper.

  The carbon fiber (E) has a crystal size (hereinafter referred to as Lc) measured by a wide-angle X-ray diffraction method, preferably 1 nm or more, more preferably 1.3 to 4 nm, and even more preferably 1 It is preferably 6 to 3 nm, particularly preferably in the range of 1.8 to 2.5 nm. When Lc is less than 1 nm, carbon fiber is not sufficiently carbonized or graphitized, and the conductivity of carbon fiber itself tends to be low, which is not preferable. In addition, the measurement of Lc by a wide angle X-ray diffraction method can be performed by the method described in Japan Society for the Promotion of Science 117th Committee, carbon, 36, p25 (1963). Carbon fibers having such a crystal size can be appropriately selected from commercially available products.

The carbon fiber (E) used in the production method of the present invention preferably has a tensile elongation at break of 1.5% or more. When the tensile elongation at break is 1.5% or more, the carbon fiber is rarely cut in the resin composition manufacturing process and molding process, and the length of the carbon fiber in the resin composition and its molded product is kept long. It is possible to improve the mechanical strength as well as further conductivity. Carbon fibers having such tensile elongation at break can be obtained by appropriately selecting from commercially available products.

  As the carbon fiber having such a crystal size and tensile elongation at break, “Torayca” T300 manufactured by Toray is preferably exemplified.

Carbon fiber used in the present onset bright (E) is previously epoxy resins the surface is treated with a urethane resin and oligomers thereof, it is particularly preferred to use cut into about 3 to 10 mm. Moreover, the diameter of carbon fiber is 3-13 micrometers normally, Preferably the thing of 5-10 micrometers is used suitably.

The amount of carbon fiber (E) used in the production method of the present invention is preferably 5 to 35 parts by weight, more preferably 10 to 10 parts by weight based on 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). 25 parts by weight. When the amount of carbon fiber (E) added is within the above range, it is preferable in that it can be expected to improve mechanical strength as well as further conductivity.

The polyamide elastomer (F) preferably used in the production method of the present invention is a polyamide elastomer containing polyether ester units or polyether units. In particular, when polyamide elastomer (F) is used in combination with conductive carbon black (D) or carbon fiber (E), it not only gives stable conductivity to the polyoxymethylene resin composition but also conductive carbon. The amount of black (D) or carbon fiber (E) added can be reduced.

  The polyamide elastomer (F) contains a polyether ester unit or a polyether unit, and is a block or graft copolymer obtained from a reaction between a polyamide-forming component (x) and a poly (alkylene oxide) glycol (y). . Such a block or graft copolymer may be obtained by further reacting the component (x) and the component (y) with the dicarboxylic acid component (z). Specific examples of the polyamide-forming component (x) include ω-aminocaproic acid, ω-aminoenanthic acid, ω-aminocaprylic acid, ω-aminopergonic acid, ω-aminocapric acid and 11-aminoundecanoic acid, 12-aminododecane. Aminocarboxylic acids such as acids or lactams such as caprolactam, enanthractam, capryllactam and laurolactam and diamine-dicarboxylic acids such as hexamethylenediamine-adipate, hexamethylenediamine-sebacate and hexamethylenediamine-isophthalate In particular, caprolactam, 12-aminododecanoic acid, and hexamethylenediamine-adipate are preferably used.

  Examples of poly (alkylene oxide) glycol (y) include poly (ethylene oxide) glycol, poly (1,2-propylene oxide) glycol, poly (1,3-propylene oxide) glycol, poly (tetramethylene oxide) glycol, Poly (hexamethylene oxide) glycol, a block or random copolymer of ethylene oxide and propylene oxide, a block or random copolymer of ethylene oxide and tetrahydrofuran, and the like are used. Among these, poly (ethylene oxide) glycol is particularly preferably used. The number average molecular weight of the poly (alkylene oxide) glycol (y) is preferably 200 to 6000, particularly preferably 400 to 4000. In addition, α, ω-diaminopoly (alkylene oxide) can be used as well as poly (alkylene oxide) glycol.

  Examples of the dicarboxylic acid component (z) include oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, bis ( p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid and the like are preferable, and in particular, adipic acid, sebacic acid, azelaic acid, dodecane Dionic acid, terephthalic acid and isophthalic acid are preferably used.

  The content of polyether ester units or polyether units in the polyamide elastomer (F) is preferably 20 to 95% by weight, particularly preferably 40 to 80% by weight.

The amount of the polyamide elastomer (F) added in the present invention is preferably 5 to 20 parts by weight, particularly 7 to 15 parts by weight, based on 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). preferable. Further, it is particularly preferable to use polyamide elastomer (F) together with conductive carbon black and carbon fiber.

In the production method of the present invention, an antistatic agent (G) may be further added.

  Preferred examples of the antistatic agent (G) include (1) aliphatic polyether (except for compounds having a terminal fatty acid ester), (2) an aliphatic polyether having a terminal fatty acid ester, ( 3) Fatty acid ester of polyhydric alcohol having free hydroxyl group obtained from fatty acid and polyhydric alcohol, (4) Boric acid ester of glycerin monofatty acid ester, (5) Ethylene oxide adduct of amine compound, (6) Basic carbonic acid Examples thereof include an antistatic agent in which a salt or an anion exchanger thereof is used as a base and a polyalkylene polyol or an alkali metal salt-dissolved polyalkylene polyol is included therein.

  (1) The aliphatic polyether is preferably a polyether having an aliphatic ether group having 2 to 4 carbon atoms as a main repeating unit, and may be a homopolymer or a copolymer. Further, regardless of the presence or absence of a side chain, the type of terminal group is not particularly limited except for the fatty acid ester described later, but is preferably an -OH terminal, and an alkoxy group (aliphatic ether) is at the -OH terminal. Accordingly, it is preferable. Examples of the aliphatic ether include methyl ether, ethyl ether, propyl ether, butyl ether, lauryl ether, stearyl ether and the like. Examples of the aliphatic polyether include polyethylene glycol, polypropylene glycol, polybutylene glycol, chlorohydrin rubber, polyethylene glycol monolauryl ether, polyethylene glycol dilauryl ether, polytetramethylene glycol and the like.

  (2) The aliphatic polyether compound whose terminal is a fatty acid ester is substituted with a saturated or unsaturated fatty acid having 10 to 37 carbon atoms and one hydroxyl group represented by the following general formulas (III) and (IV) It is preferable that the fatty acid diester compound and the fatty acid monoester compound obtained from the fatty acid being used and the alkylene glycol having 2 to 6 carbon atoms.

（ただし、式中Ｒ^９、Ｒ^１０は炭素数９〜３６のアルキル基もしくはアルケニル基および１つの水酸基で置換されている該アルキル基もしくはアルケニル基で、Ｒ^９とＲ^１０は同一であっても異なっていても良く、Ｒ^１１Ｏは炭素数２〜６のアルキレングリコールユニットを表す。また、ｑは１〜７０の整数を表す。）

(In the formula, R ⁹ and R ¹⁰ are an alkyl group or alkenyl group having ^{9 to} 36 carbon atoms and an alkyl group or alkenyl group substituted with one hydroxyl group, and R ⁹ and R ¹⁰ may be the same. R ¹¹ O represents an alkylene glycol unit having 2 to 6 carbon atoms, and q represents an integer of 1 to 70.

（ただし、式中Ｒ^１２は、炭素数９〜３６のアルキル基もしくはアルケニル基および１つの水酸基で置換されている該アルキル基もしくはアルケニル基で、Ｒ^１３Ｏは炭素数２〜６のアルキレングリコールユニットを表す。また、ｒは１〜７０の整数を表す。）

Wherein R ¹² is an alkyl group or alkenyl group having 9 to 36 carbon atoms and an alkyl group or alkenyl group substituted with one hydroxyl group, and R ¹³ O is an alkylene glycol unit having 2 to 6 carbon atoms. Moreover, r represents an integer of 1 to 70.)

  Fatty acid diester compounds and fatty acid monoester compounds are capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid and other alkylene glycols having 1 to 70 addition moles. It is preferable that it is an ester compound obtained by reaction with.

  Among them, preferably, the fatty acid is myristic acid, palmitic acid, and stearic acid, and the alkylene glycol is a fatty acid diester compound and a fatty acid monoester compound that are (poly) ethylene glycol, and the number of moles of ethylene glycol added is 1 to 10. It is. The number of moles of ethylene glycol added is more preferably 1-5. Examples of the aliphatic polyether compound having a terminal fatty acid ester include polyethylene glycol dilaurate, polyethylene glycol monostearate, polypropylene glycol distearate, polytetramethylene monostearate and the like.

  (3) Fatty acid ester of polyhydric alcohol having free hydroxyl group obtained from fatty acid and polyhydric alcohol is lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, montanic acid, citric acid, oleic acid, It is preferably a fatty acid ester alcohol having at least one free hydroxyl group and at least one ester group obtained by reacting a fatty acid such as hydroxystearic acid with a polyhydric alcohol such as glycerin, pentaerythritol, diglycerin or sorbitol. . Examples of fatty acid esters of polyhydric alcohols having free hydroxyl groups obtained from fatty acids and polyhydric alcohols include glycerin monostearate, glycerin distearate, pentaerythritol monostearate, pentaerythritol dilaurate, dipentaerythritol distearate, etc. Is preferred.

  (4) The boric acid ester of glycerin monofatty acid ester is a reaction of fatty acid such as glycerin and lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, montanic acid, citric acid, oleic acid, hydroxystearic acid, etc. Preferred is a borate ester of a diol ester obtained by

  (5) The ethylene oxide adduct of an amine compound is preferably an ethylene oxide adduct of an amine compound represented by the general formula (V).

（ただし、式中Ｒ^１４は、炭素数１０〜２２のアルキルまたはアルケニル基であり、ｓおよびｔはいずれも１〜１０の整数を示す。）
若しくは、一般式（ＶＩ）で表されるアミド化合物が挙げられる。

(In the formula, R ¹⁴ is an alkyl or alkenyl group having 10 to 22 carbon atoms, and s and t each represent an integer of 1 to 10)
Or the amide compound represented by general formula (VI) is mentioned.

（ただし、式中Ｒ^１５はカルボン酸残基、ｕ、ｖはそれぞれ０または１以上の整数を示す。）

(In the formula, R ¹⁵ represents a carboxylic acid residue, and u and v each represents 0 or an integer of 1 or more.)

  (6) An antistatic agent in which a basic carbonate or an anion exchanger thereof is used as a base and a polyalkylene polyol or an alkali metal salt-dissolved polyalkylene polyol is included is aluminum, lithium, hydroxy carbonate or aluminum. -What included polyalkylene glycol, such as polyethyleneglycol, or its derivative | guide_body in sodium hydroxy carbonate etc. is mentioned preferably.

The amount of antistatic agent (G) used in the production method of the present invention varies depending on the type of antistatic agent to be added and the required antistatic performance, and is not generally determined. It is preferable that it is 0.01-10 weight part with respect to 100 weight part of crude polymers of (A). If the addition amount of the antistatic agent (G) is less than 0.01 parts by weight, sufficient antistatic performance cannot be obtained, and if it is more than 10 parts by weight, the mechanical properties are greatly impaired.

In the method for producing the resin composition of the present invention, a colorant (H) may be further added.

This onset facie preferably used colorant (H) are inorganic and organic pigments. The inorganic pigment is not particularly limited as long as it is an inorganic pigment used for resin coloring. For example, titanium oxide, titanium yellow, white lead, red lead, yellow lead, complex oxide pigment, zinc sulfide, zinc oxide, sulfide Barium, iron oxide, ultramarine blue, bitumen, cobalt blue, calcined pigment, carbonate, phosphate, acetate, carbon black, titanium black, acetylene black, lamp black, and the like can be used. The organic pigment is not particularly limited as long as it is an inorganic pigment used for coloring a resin, and is condensed azo, disazo, monoazo, diketopyrrolopyrrole, isoindolinone, anthraquinone, heterocyclic, quinacridone. Pigments such as pigments, thioindico, perinone, perylene, dioxazine, and phthalocyanine. The colorant (H) is particularly preferably carbon black or titanium oxide in that the color change is particularly small. These colorants can be used alone or in combination of two or more.

The addition amount of the colorant (H) in the production method of the present invention varies depending on the required color tone and is not generally determined, but is 0 with respect to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). It is preferable that it is 0.01-3 weight part.

  Moreover, when using a coloring agent (H) as a masterbatch, the addition amount of a masterbatch changes with dilution rate or a color tone, and although it is not decided unconditionally, Preferably it is 1 to 100 weight part of compositions. It is preferably 70 parts by weight, more preferably 20 to 30 parts by weight, and it is preferable that the same amount of colorant as that of the kneaded colored product is added to the final product.

In the production method of the present invention, it is further preferable to use an amide wax, a polyolefin wax or the like as a dispersant for the colorant.

In the method for producing the resin composition of the present invention, the heat stabilizer (I) may be added.

This onset facie preferably heat stabilizer used (I) is, urethane compounds, pyridine derivatives, pyrrolidone derivatives, urea derivatives, triazine derivatives, hydrazine derivatives, amidine compounds, polyamides and polyamide copolymers, polyacrylamide and polyacrylamide copolymerization Examples include melamine, benzoguanamine, acetoguanamine, N-methylol melamine, N, N′-dimethylol melamine, N, N ′, N ″ -tri, and the like. Preferred are methylolmelamine, dicyandiamide, nylon 6, nylon 6/12 copolymer, nylon 6/66/610 terpolymer, nylon 6/66/610/12 quaternary copolymer, polyacrylamide, among others Melamine is particularly preferred.

The amount of these heat stabilizers (I) added is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 0. 0, with respect to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). 5 parts by weight. If the addition amount of the heat stabilizer (I) is less than 0.01 parts by weight, the effect of addition of heat stability does not appear, and if it is more than 10 parts by weight, coloring or bleeding phenomenon is observed, which is not preferable.

In the method for producing the polyoxymethylene resin composition of the present invention, a lubricant (J) may be further added. Suitable examples of lubricants include mineral oil, liquid paraffin, paraffin wax, fatty acids, aliphatic alcohols, alcohols such as trihydric or higher polyhydric alcohols, aliphatic amides, fatty acid metal salts, fatty acid esters, and the above alcohols. Examples include esters with fatty acids, esters of polycarboxylic acids and aliphatic alcohols, glycols, adducts of alkylene oxides to alcohols, adducts of alkylene oxides to fatty acids, and the like. In addition, polyolefin wax, silicone oil, polyalkylene glycol and the like having a number average molecular weight of less than 1000 can be used.

  Specifically, fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and montanic acid; aliphatic alcohols such as hexyl alcohol, octyl alcohol, cetyl alcohol, stearyl alcohol, and behenyl alcohol; ethylene glycol , Glycols such as propylene glycol, butylene glycol and 1,4-butanediol; trihydric or higher polyhydric alcohols such as glycerin, polyglycerin, pentaerythritol and polytetrahydroxyfuran; esters of the fatty acids and alcohols; the alcohols Oxide oxide adducts to fatty acids; fatty acid amides such as stearylamide, palmitylamide, oleylamide, methylenebisstearylamide, ethylenebisstearylamide; Um, zinc stearate, fatty acid metal salts such as magnesium stearate is preferably exemplified.

The lubricant (J) can be added in an amount of preferably 0.01 to 15 parts by weight, more preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). When the addition amount of the lubricating oil is less than 0.01 parts by weight, a sufficient addition effect cannot be obtained, and when it is more than 15 parts by weight, the mechanical properties are deteriorated.

Furthermore, the inorganic filler (K) may be added to the method for producing the polyoxymethylene resin composition of the present invention. The inorganic filler (K) is in the form of a fiber, particle, plate or the like. As the fibrous filler, glass fiber, silicon fiber, silica / alumina fiber, fibrous boehmite, ceramic fiber, potassium titanate whisker, fibrous zonotolite, acicular wollastonite, metal oxide whisker, boron fiber and the like are preferable. Can be mentioned. Preferred examples of the particulate filler include calcium carbonate, magnesium carbonate, talc, silica, clay, bentonite, kaolin, diatomaceous earth, perlite, feldspar, carbon black, white carbon, glass beads, barium sulfate, and hydroxyapatite. Preferable examples of the plate-like filler include mica, glass flakes, and graphite. These inorganic fillers (K) can also be surface-treated. As the surface treatment agent, a known coupling agent such as silane or titanate can be used.

The inorganic filler (K) can be added in an amount of preferably 0.1 to 100 parts by weight, more preferably 0.5 to 50 parts by weight, based on 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). . If the addition amount of the inorganic filler is less than 0.1 parts by weight, a sufficient addition effect cannot be obtained, and if it is more than 100 parts by weight, the moldability is lowered, which is not preferable.

Further, the production method of the resin composition of the present invention, it added molecular weight of 400 or more hindered amine compound (L). As the hindered amine compound (L), a hindered amine compound described as a deactivator of polyoxymethylene resin in JP-A No. 62-257922 can be used. A tertiary amine type hindered amine compound having a molecular weight of 400 or more can be used. To compound . By molecular weight used as the 400 or more, bleeding phenomenon is extremely suppressed, appearance, outstanding polyoxymethylene resin composition heat stability Ru obtained.

  Hindered amine compounds (L) having a molecular weight of 400 or more are bis (1,2,2,6,6-pentamethyl-4-piperidinyl) 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-piperidinyl) 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-piperidinyl} imino] hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}]], Screw (2 Such as 2,6,6-tetramethyl-4-piperidyl) sebacate may preferably be mentioned. Of these, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate are more preferred. It is preferable to use at least one hindered amine compound selected from these. Among them, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate is particularly preferable, and as such a compound, a commercially available product as Sankyo “Sanol” LS765 can be used.

The amount of molecular weight 400 or more hindered amine compound (L) is to the crude polymer 100 parts by weight of polyoxymethylene resin (A) 0. 01 to 10 parts by weight . Good Mashiku is 0.01 to 3 parts by weight. From the viewpoint of thermal stability of the resin composition, it is preferably at least the above lower limit, and from the viewpoint of coloring by heat, it is preferably at most the above upper limit.

As described above, the hindered amine compound (L) can be contained in the polyoxymethylene resin (A) as a quencher, and the hindered amine compound (L) is added to the polyoxymethylene resin (A). The catalyst may be deactivated by a method other than that described above and then added to the polyoxymethylene resin (A) to be contained, or these may be used in combination. In the method for producing a resin composition of the present invention, in order to exert the above-described effects remarkably, it is preferable to use the hindered amine compound (L) as at least a deactivator and to contain it in the polyoxymethylene resin (A).

In the method for producing the resin composition of the present invention, a hindered phenol compound (M) having a molecular weight of 400 or more can be further added. The hindered phenol compound (M) preferably has a molecular weight of 400 or more. By using a hindered phenol compound (M) having a molecular weight of 400 or more, a bleed phenomenon is extremely suppressed, and a polyoxymethylene resin composition having excellent appearance and thermal stability is obtained. Furthermore, by using a hindered amine compound (L) and a hindered phenol compound (M) in combination, a polyoxymethylene resin composition having better thermal stability can be obtained.

  Preferred examples of the hindered phenol compound (M) include triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5-di-tert-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-tert-butyl-4-hydroxy-5-methylphenyl) propionyl Carboxymethyl} -1,1-dimethylethyl] -2,4,8,10-spiro [5,5] undecane. 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] are particularly preferred. It is preferable to use at least one hindered phenolic compound (M) selected from these as an antioxidant for the polyoxymethylene resin composition.

The amount of the hindered phenol compound (M) added is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 3 parts per 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). From the viewpoint of thermal stability of the polyoxymethylene resin composition, it is preferably at least the above lower limit, and from the viewpoint of the bleeding phenomenon of the additive, it is preferably at most the above upper limit.

In addition, the method for producing the resin composition of the present invention includes an aramid fiber, an organic reinforcing agent, a nucleating agent, a plasticizer, a release agent such as polyethylene wax, a thioether compound, and a phosphite within a range not impairing the effects of the present invention. Addition of antioxidants such as compounds, light stabilizers such as benzophenone compounds and benzotriazole compounds, adhesives, lubricants such as metal soap, hydrolysis resistance improvers, adhesion aids, formic acid scavengers, etc. An agent can be optionally contained.

In the method for producing a polyoxymethylene resin composition of the present invention, a mixture of trioxane and a cyclic ether is mixed with boron trifluoride, boron trifluoride hydrate, and an organic compound containing boron trifluoride and an oxygen atom or a sulfur atom. In the presence of at least one polymerization catalyst selected from the group consisting of the above coordination compounds to produce an oxymethylene homopolymer by homopolymerizing an oxymethylene unit, or an oxymethylene unit and another oxyalkylene unit. When producing an oxymethylene copolymer by copolymerization, tripotassium citrate (100 parts by weight of the crude polymer of the polyoxymethylene resin (A) obtained by deactivating the polymerization catalyst after completion of the polymerization ( B) is added in an amount of 0.001 to 10 parts by weight and heated in a temperature range of 100 to 260 ° C. After the addition of tripotassium citrate (B), heating in a temperature range of 100 to 260 ° C. is highly effective in reducing the amount of formaldehyde generated during actual use and / or molding.

When tripotassium citrate (B) is added to a crude polymer of oxymethylene homopolymer or oxymethylene copolymer, after mixing at a temperature below the melting point of the crude polymer using a mixer, 100 to 260 More preferably, it is used for heating in a temperature range of ° C. Mixing at a temperature below the melting point of the crude polymer using a mixer is preferable because tripotassium citrate (B) can be uniformly dispersed in the crude polymer of the polyoxymethylene polymer.

Tripotassium citrate (B) is added to the polyoxymethylene polymer crude polymer, mixed using a mixer, and then heated and kneaded in a temperature range of 170 to 260 ° C. using a vented twin screw extruder. More preferably. When heated and kneaded in a temperature range of 170 to 260 ° C. using a vented twin screw extruder, tripotassium citrate (B) is uniformly dispersed in the polyoxymethylene resin, and a metal formate, a by-product carboxylic acid, The condensate, self-condensate, solvent and other volatile impurities are preferably removed from the polyoxymethylene resin.

Furthermore, the manufacturing method of the polyoxymethylene resin composition, in order to improve the dispersibility of tripotassium citrate (B), it added tripotassium citrate and (B) a mixture mixed with a solvent. The solvent used is water . In addition, the compounding quantity of water becomes like this. Preferably it is 0.01-10 weight part with respect to 100 weight part of crude polymers of a polyoxymethylene resin (A), More preferably, it is 0.05-3 weight part. The blending amount of water is preferably not less than the above lower limit from the viewpoint of dispersibility of tripotassium citrate (B), and is preferably not more than the above upper limit from the viewpoint of temperature control during heating.

The method for producing a polyoxymethylene resin composition comprises a hindered amine compound (L) and / or a polymerization catalyst deactivator for the polyoxymethylene resin (A) at the final stage of the polymerization step or after the completion of the polymerization. It can also be added as a heat stabilizer. Furthermore, a hindered phenol compound (M) or tripotassium citrate (B) can be added in either the polymerization step or the stabilization step. Alternatively, the polyoxymethylene resin (A), tripotassium citrate (B), hindered amine compound (L) and hindered phenol compound (M) as optional components are mixed in the form of pellets, powders, or granules, and left as they are. It may be melt processed. As a preferable melt processing method, a melt kneading method using a Banbury mixer, a roll, an extruder or the like can be adopted.

  The polyoxymethylene resin composition obtained by the present invention is a resin composition with greatly improved thermal stability in a high-temperature molten state without impairing the excellent properties inherent in the polyoxymethylene resin. Since the generation of formaldehyde from the oxymethylene resin composition is suppressed, it is possible to obtain a molded product with extremely low color tone and generation of formaldehyde odor and mold deposit during continuous molding.

Specifically, the polyoxymethylene resin composition obtained by the present invention hardly shows formaldehyde odor even when 10,000 shots of test pieces are continuously injection molded. Further, even when the polyoxymethylene resin composition obtained by the present invention is subjected to heat treatment at 240 ° C. for 15 minutes, the amount of formaldehyde generated is almost 500 ppm or less, at most 900 ppm or less, and mold deposits are extremely generated. Less was found.

  Therefore, since there is almost no formaldehyde odor during injection molding and the amount of formaldehyde generated during heating and melting is greatly reduced, continuous production of tens of thousands to hundreds of thousands of shots is possible in actual production lines. It is. Thereby, the operation of the molding machine is stopped, and the work of purifying the mold and the work of disassembling and cleaning can be greatly reduced. Furthermore, it can be expected to contribute to the improvement of work environment and production efficiency.

Thus obtained Lupo Li oxymethylene resin composition typically known injection molding, extrusion molding, press molding, hot pressing, it is possible to mold in the process of stamping or the like.

The polyoxymethylene resin composition obtained by the present invention enables long-term continuous production of molded articles, and can be used in a wide range as mechanical mechanism parts in the electric / electronic field, the automobile field, and the like.

Molded articles to which the polyoxymethylene resin composition obtained by the present invention is applied include sensors, LED lamps, connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, and various types. Terminal board, transformer, plug, printed circuit board, tuner, speaker, microphone, headphones, small motor, magnetic head case, power module, semiconductor, liquid crystal, FDD carriage, FDD chassis, magnetic tape cassette reel, motor brush holder, parabolic antenna It is suitably used for electrical and electronic parts such as computer-related parts, but other uses, ie VTR parts, VTR camera parts, TV parts, irons, hair dryers, shavers, electric fans. Typical examples include juicers, rice cooker parts, microwave oven parts, audio equipment parts such as headphones, stereo cassettes, audio, laser discs, compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, calculators, word processor parts, etc. Household, office electrical product parts, office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, cleaning jigs, motor parts, lighters, typewriters and other machine-related parts, microscopes, binoculars, Optical devices such as cameras and watches, precision machine parts, alternator terminals, alternator connectors, IC regulators, light meter potentiometer bases, various valves such as exhaust gas valves, fuel and exhaust systems Various intake system pipes, air intake nozzle snorkel, intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil temperature sensor, brake pad wear sensor, throttle position sensor, crank Shaft 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, distributor, starter switch, Starter relay, wire harness for transmission, air conditioner panel switch board, Fuel related electromagnetic valve coil, fuse connector, horn terminal, electrical component insulation plate, step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, solenoid bobbin, engine oil filter, ignition device case, 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, collapsible Bullroom mirror stays, seat hooks, fender mirror cases, fuel cups, window washer nozzles, various parts such as valves, bicycles, lawn mowers, partition corner pieces, curtain runners, blind gears, doors, bindings, offices Furniture parts, various fasteners, piping systems, hose joints, valves, fasteners, adjustments, meters, shoe parts, sports equipment, toys, music boxes, combs and other beauty products, caster brackets, rollers, caps, measure parts, aerosol hoses, etc. It can also be used for various other general equipment parts.

  Examples are described below, but the present invention is not limited to these examples.

The following examples illustrate the invention. In addition, all the parts of each composition component in an Example and a comparative example are a basis of weight, and let the compounding quantity of the rough polymer of a polyoxymethylene resin (A) be 100 weight part. Further, the mechanical properties, color tone, formaldehyde odor generation state during continuous molding, formaldehyde amount during heating, and MI value of the molded products shown in Examples and Comparative Examples were measured or observed as follows.

Molding: An ASTM No. 1 dumbbell test piece was injection molded using an injection molding machine having an injection capacity of 5 ounces, with a cylinder temperature of 190 ° C., a mold temperature of 65 ° C., and a molding cycle of 50 seconds.

Mechanical properties: Tensile strength (unit: MPa) was measured according to ASTM D-638 method using ASTM No. 1 dumbbell test piece obtained by the above injection molding.

-Color tone: Color tone (YI value; JIS K-7103 method) using SM color computer (SM-5-1S-2B) of Suga Test Instruments Co., Ltd. using ASTM No. 1 dumbbell test piece obtained by the above injection molding Compliant).

-Generation status of formaldehyde odor during continuous molding: 10,000 shots were continuously molded under the above-mentioned molding conditions, and the generation status of formaldehyde odor at that time was evaluated as follows.
○: Almost no formaldehyde odor.
Δ: Slightly formaldehyde odor
X: Formaldehyde gas is considerably generated, and eyes and throat become sore when in the place, or formaldehyde gas is generated so much that the person cannot stay there.

-Amount of formaldehyde generated during heating: About 1 g of pellets dried for 3 hours in a hot air oven at 80 ° C was used for 15 minutes at 240 ° C in a nitrogen atmosphere, and the generated formaldehyde was trapped in a methanol aqueous solution. The amount of formaldehyde in the methanol aqueous solution was quantified by oxidation-reduction titration, and the amount of formaldehyde generated during heating (unit: ppm) was measured.

MI value: MI value (unit: g / 10 min) was measured under the conditions of a temperature of 190 ° C. and a load of 2160 grams according to ASTM D-1238 method using pellets dried for 3 hours in a hot air oven at 80 ° C.

The contents of the polyoxymethylene resin (A), tripotassium citrate (B) and other raw materials used in the examples and comparative examples are shown below.

-Oxymethylene copolymer (A-1): Triaxial (22.5 kg / h) in a twin-screw extruder type polymerizer (100 mm diameter, cylinder length (L) / cylinder diameter (D) = 10.2), 1,3-dioxolane (700 g / h), 100 ppm boron trifluoride / diethyl etherate (2.5% benzene solution) as a catalyst for trioxane, and 600 ppm methylal as a molecular weight regulator, Continuous polymerization was performed. The polymerization was performed by controlling the outer jacket at 60 ° C. and rotating at 100 rpm. Methylal was 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. The crude polymer of the oxymethylene copolymer was obtained as a white fine powder at 22.4 kg / h.

9.0 g of “Sanol” LS765 [Sankyo Pharmaceutical Co., Ltd., bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate for 5 kg of the fine powder of the obtained oxymethylene copolymer crude polymer The tertiary amine type hindered amine compound] dissolved in 50 ml of benzene was added, and the mixture was stirred for 3 minutes in a Henschel mixer to deactivate the catalyst to obtain an oxymethylene copolymer (A-1). It was .

Sodium malate (B-7), potassium malate (B-8), trisodium citrate (B-10), tripotassium citrate (B-11) , and sodium tartrate (B-14): Kanto respectively The thing by a chemical company was used.

Calcium 12-hydroxystearate (B-16): Daiichi Chemical “Diewax OHC” was used.

Calcium hydroxide (B-17): A product manufactured by Kanto Chemical Co., Inc. was used.
Low density polyethylene 1 (C-1): Mitsui Chemicals “Ultzex” 20200J was used.

Low density polyethylene 2 (C-2): Mitsui Chemicals “Evolue” SP0540 was used.

-Ethylene / glycidyl methacrylate copolymer (C-3): Sumitomo Chemical "Bond First" E was used.

-Ethylene / ethyl acrylate copolymer (C-4): Mitsui DuPont polychemical "Evaflex" A709 was used.

Polyethylene-g-acrylonitrile styrene copolymer (C-5): Nippon Oil & Fats “Modiper” A1401 (graft copolymer of low density polyethylene and acrylonitrile styrene copolymer) was used).

Polyethylene-g-polymethyl methacrylate (C-6): Nippon Oil & Fats “Modiper” A1201 (graft copolymer of low density polyethylene and polymethyl methacrylate) was used.

Silicone polymer (C-7): Toray Dow Corning silicone polydimethylsiloxane SH200 (viscosity 5000 cs) was used.

Fluoropolymer (C-8): Kureha Chemical Industry “KF polymer” # 850 was used.
-Polyether polymer (C-9): Polyethylene glycol having an average molecular weight of 6000 manufactured by Kanto Chemical Co., Inc. was used.

Conductive carbon black 1 (D-1): “Ketjen Black EC600DJ” manufactured by Lion Akzo was used.

Conductive carbon black 2 (D-2): “# 3050” manufactured by Mitsubishi Chemical was used.
Conductive carbon black 3 (D-3): “Toka Black # 4500” manufactured by Tokai Carbon Co., Ltd. was used.

Carbon fiber (E-1): A PAN-based carbon fiber (Torayca “T300” manufactured by Toray) having a diameter of 7 μm was used.

Polyamide elastomer (F-1): 50 parts by weight of caprolactam, 44.2 parts by weight of polyethylene glycol having a number average molecular weight of 1000 and 7.8 parts by weight of terephthalic acid, 0.3 parts by weight of “Irganox” 1098 (antioxidant) And 0.1 part by weight of an antimony trioxide catalyst were charged into a reactor equipped with a helical ribbon stirring blade, purged with nitrogen, heated and stirred at 260 ° C. for 60 minutes to obtain a transparent homogeneous solution, and then 260 ° C., 70 Pa Polymerization was performed for 3 hours and 30 minutes under the following conditions to obtain a viscous and transparent polymer. The polymer was discharged onto a cooling belt in the form of a gut and pelletized to prepare a pellet-like polyamide elastomer.

Polyethylene glycol (G-1): Polyethylene glycol having an average molecular weight of 6000 manufactured by Kanto Chemical Co., Inc. was used.

Polyethylene glycol monostearate (G-2): Kao “Emanon” 3199 was used.

Glycerin monostearate (G-3): Kao “Excel” T-95 was used.
· NOF Nymeen _{L202 (G-4): C} 12 H 25 -N [(CH 2 CH 2 O) n H] 2

Polyethylene glycol adduct of aluminum / lithium / hydroxy carbonate (G-5): 50.0 g of sodium hydroxide and 14.9 g of sodium carbonate were added to 4.0 liters of water with stirring and heated to 40 ° C. . Next, 18.66 g of lithium carbonate and 99.56 g of aluminum chloride were dissolved in 0.8 liter of water so that the molar ratio of CO ₃ / Li was 2.0 and the molar ratio of Al / Li was 1.5. The slurry was gradually poured to obtain a slurry with pH = 10.7. Next, aging is carried out at a temperature of 80 to 100 ° C. for about 10 to 18 hours with stirring, after which 1.1 g of stearic acid is added, surface treatment is performed with stirring, filtration, washing with water and drying at 70 ° C. An anion exchanger was obtained by pulverizing with a sample mill. Next, based on 100 parts by weight of this anion exchanger, 80 parts by weight of polyethylene glycol having a molecular weight of 2000 in which 2 parts by weight of LiClO ₄ was dissolved was melted in a boiling water bath, mixed and cooled in a mixer, and then mixed with aluminum, lithium, A polyethylene glycol adduct of hydroxy carbonate was obtained.

Titanium oxide (H-1): Ipehara Sangyo's Typeke CR-63 was used.
Carbon black (H-2): Mitsubishi Chemical # 650 was used.

Melamine (I-1): A product manufactured by Kanto Chemical Co., Inc. was used.
Polyamide 6/66/610/12 quaternary copolymer (I-2): A copolymer having a copolymer composition of 6/66/610/12 = 22/16/12/50 (wt%) was used.

Polyacrylamide (I-3): Sumitomo Chemical “polyacrylamide” was used.
Glycerol monostearate (J-1): Kao “Excel” T-95 was used.

Calcium stearate (J-2): Japanese fat and oil “Calcium stearate” was used.

Ethylene bisstearylamide (J-3): Lion “Armowax” EBS was used.

-Talc (K-1): Fuji Talc LMS-300 was used.
Calcium carbonate (K-2): Dowa Kasei “Ace” 25 was used.

[ Reference Example 1-1 ]
<Preparation of polyoxymethylene resin composition>
With respect to 5 kg of polyoxymethylene copolymer (A-1) after deactivation of the catalyst (this is defined as 100 parts by weight), “Irganox” 245 [Ciba Geigy, triethylene glycol-bis {3- (3 -T-butyl-5-methyl-4-hydroxyphenyl) propionate}, hindered phenol compound] 25 g, tripotassium citrate (B) in advance at room temperature in the proportions shown in Table 1, The mixture was melt-kneaded for 5 minutes under reduced pressure at a cylinder temperature of 210 ° C. and 10 Torr with a 2-shaft 30 mm diameter extruder with a vent.

  The obtained resin composition was extruded as a strand and pelletized with a cutter.

<Molding and evaluation>
The pellets were dried in a hot air circulating oven at 80 ° C. for 3 hours, and the amount of formaldehyde generated during heating and the MI value were evaluated. These results are summarized in Table 1 .

  Next, an ASTM No. 1 dumbbell test piece was injection molded using the dried pellets, and mechanical properties and color tone were measured. Furthermore, the occurrence of formaldehyde odor during continuous molding was evaluated.

[Examples 9-1 to 9-5, Comparative examples 9-1 to 9-4]
A polyoxymethylene resin composition was obtained in the same manner as in Reference Example 1-1 except that tripotassium citrate (B) was added as a mixture mixed at a ratio shown in Table 9 using water as a solvent. It was. The obtained resin composition was molded and evaluated in the same manner as in Reference Example 1-1, and the results are shown in Table 1 .

From the results in Table 1, the following matters are clear.

(1) By adding 0.001 to 10 parts by weight of tripotassium citrate (B) to 100 parts by weight of polyoxymethylene resin (A), there is very little formaldehyde odor and mold deposit at the time of molding and heat stability. excellent sex, and polyoxymethylene resin composition excellent in color tone is Ru obtained.

( 2 ) Even when tripotassium citrate (B) is added as a mixture mixed with a solvent, excellent characteristics equivalent to or higher than those of Example 1-1 are exhibited. (Examples 9-1 to 9-5)

( 3 ) If the tripotassium citrate (B) is less than 0.001 part by weight and more than 10 parts by weight, the formaldehyde odor and mold deposit at the time of molding deteriorate and the thermal stability becomes insufficient. And / or the color tone deteriorates. (Comparative Examples 9-1 to 9-4)

Claims (19)

A mixture of trioxane and cyclic ether is selected from the group consisting of boron trifluoride, boron trifluoride hydrate, and a coordination compound of boron trifluoride and an organic compound containing an oxygen atom or a sulfur atom. An oxymethylene copolymer is produced by homopolymerizing an oxymethylene unit in the presence of a polymerization catalyst to produce an oxymethylene homopolymer, or by copolymerizing an oxymethylene unit with another oxyalkylene unit. In this case, after the completion of the polymerization, the polymerization catalyst is added to a hindered amine compound (L) having a molecular weight of 400 or more represented by the following general formula (II) with respect to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). by adding .01～10 parts, crude polymer 100 parts by weight of the polyoxymethylene resin obtained by deactivating (a) In contrast, tripotassium citrate (B) was added 0.001 parts by weight of a mixture obtained by mixing with water, producing a polyoxymethylene resin composition characterized by heating at a temperature range of 100 to 260 ° C. Method.

(However, in the formula, R ³ represents a hydrogen atom or a monovalent organic residue having 1 to 30 carbon atoms. R ^{4 to} R ⁷ each represents an alkyl group having 1 to 5 carbon atoms. ( P represents an integer of 1 or more, and R ⁸ represents a p-valent organic residue.)   The tripotassium citrate (B) is added to the crude polymer, mixed at a temperature below the melting point of the crude polymer using a mixer, and then heated in a temperature range of 100 to 260 ° C. The manufacturing method of the polyoxymethylene resin composition of Claim 1 characterized by the above-mentioned.   The tripotassium citrate (B) is added to the crude polymer, mixed using a mixer, and then heated and kneaded in a temperature range of 170 to 260 ° C. using a twin screw extruder with a vent. The manufacturing method of the polyoxymethylene resin composition of Claim 2 characterized by the above-mentioned. Wherein the crude polymer 100 parts by weight of polyoxymethylene resin (A), the further any one of the sliding property improving agent (C) obtained by adding 0.1 to 20 parts by weight according to claim 1 to 3, wherein The manufacturing method of the polyoxymethylene resin composition as described in 2. The method for producing a polyoxymethylene resin composition according to claim 4 , wherein the slidability improver (C) contains an olefin polymer. The sliding property improving agent (C) is an olefin-based polymer, according to claim 4 are those containing olefinic graft copolymer of one or more of the vinyl polymer or ether polymer The manufacturing method of the polyoxymethylene resin composition as described in 2. The slidability improver (C) contains an olefin copolymer of an olefin monomer and one or more of an acrylic monomer or a methacrylic monomer. Item 5. A method for producing a polyoxymethylene resin composition according to Item 4 . The method for producing a polyoxymethylene resin composition according to claim 4 , wherein the slidability improver (C) contains one or two selected from a silicone polymer and a fluorine polymer. Poly according to any one of the the crude polymer 100 parts by weight of polyoxymethylene resin (A), the claim 1-8 comprising adding further 1 to 10 parts by weight of conductive carbon black (D) A method for producing an oxymethylene resin composition. Furthermore, the manufacturing method of the polyoxymethylene resin composition of Claim 9 formed by adding carbon fiber (E). Furthermore, the manufacturing method of the polyoxymethylene resin composition of Claim 9 or 10 formed by adding the polyamide elastomer (F) containing a polyether ester unit or a polyether unit. The polyoxyethylene according to any one of claims 1 to 11 , wherein 0.01 to 10 parts by weight of an antistatic agent (G) is added to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). A method for producing an oxymethylene resin composition. The polyoxy of any one of claims 1 to 12 , wherein 0.01 to 3 parts by weight of a colorant (H) is added to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). A method for producing a methylene resin composition. The method for producing a polyoxymethylene resin composition according to claim 13 , wherein the colorant (H) is titanium oxide and / or carbon black. The poly (ethylene) according to any one of claims 1 to 14 , wherein 0.01 to 10 parts by weight of a heat stabilizer (I) is added to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). A method for producing an oxymethylene resin composition. The method for producing a polyoxymethylene resin composition according to claim 15 , wherein the heat stabilizer (I) is melamine. The polyoxy of any one of claims 1 to 16 , wherein 0.01 to 15 parts by weight of a lubricant (J) is added to 100 parts by weight of the crude polymer of the polyoxymethylene resin (A). A method for producing a methylene resin composition. Poly according to any one of the the crude polymer 100 parts by weight of polyoxymethylene resin (A), the inorganic filler claim (K) and obtained by adding 0.1 to 100 parts by weight of 1 to 17 A method for producing an oxymethylene resin composition. The crude polymer 100 parts by weight of the polyoxymethylene resin (A), the claim 1-18 for molecular weight of 400 or more hindered phenol compound (M) obtained by adding 0.01 to 10 parts by weight A method for producing the polyoxymethylene resin composition according to item 1.