WO2006043378A1 - Polyacetal resin composition and molded article - Google Patents

Abstract

Disclosed is a polyacetal resin composition which contains a polyacetal resin (a) and a polyester resin (b) and satisfies the following condition (I) or (II). (I) A polyester resin (b), wherein ethylene succinate units or butylene succinate units account for 70-100 mol% of the main chain, is contained in an amount of 0.5-100 parts by weight per 100 parts by weight of a polyacetal resin (a). (II) A polyglycolic acid polyester resin (b'), wherein glycolic acid units account for 70-100 mol% of the main chain, is contained in an amount of 100 parts by weight per not less than 0.5 parts by weight but less than 100 parts by weight of a polyacetal resin (a).

Description

Polyacetal resin composition and molded article Technical Field

 The present invention relates to a polyacetal resin composition and a molded article thereof. Prior art

 Polyacetal resin has been used in a very wide range of fields in recent years as a typical engineering resin with excellent physical properties such as mechanical properties and electrical properties, and chemical properties such as chemical resistance and heat resistance. With the expansion of the field of use, further improvements in the properties as materials have been required.

 One such required characteristic is dimensional stability. In other words, polyacetal resin is generally molded by injection molding, extrusion molding, etc., and is used for industrial use as a molded product. With the recent increase in the accuracy of industrial products, polyacetal resin has been developed. There is a case where a high degree of dimensional stability is required even for a molded product. In addition, there are many requests from the market to improve the impact resistance of polyacetal resins. Conventionally, regarding the improvement of dimensional stability of polyacetal resin, for example, polyacetal resin molding material GP-A 6-207080 having a specific crystallization time blended with additives and polyolefin, polylactic acid resin, polyacetal resin and others A resin composition UP-A 2003-342460) containing a thermoplastic resin is proposed. However, these resin compositions tend to vary in effect, and the reproducibility of the effect may be insufficient.

On the other hand, as a method to improve the impact resistance of polyacetal resin, addition of ionomer (JP-B 45-8023), addition of ethylene monoacrylic acid copolymer (JP-B) 45-26231), addition of aliphatic polyether () P-B 50-33095), addition of thermoplastic polyurethane UP-A 59-145243 and JP-A 61- 1 9 652), addition of polyester elastomer ( JP-A 5 1-64560) has been proposed. However, although the compositions according to these proposals show some improvement in impact resistance properties, they are not always sufficient, and all of them are poorly compatible and dispersible with respect to polyacetal resin, and this is the surface of the molded product. It also affects the condition and often causes a surface peeling phenomenon that significantly impairs its appearance. These disadvantages are largely due to the low affinity between the polyacetyl resin and the added filler material, and further improvements are eagerly desired.

 Polyglycolic acid is one of the aliphatic polyesters that has a very high density, high melting point, excellent mechanical properties, and has recently been attracting attention as an environmentally low impact plastic with natural disintegration. -72529). The crystallization rate of polydalicolic acid is faster than other aliphatic polyesters such as polylactic acid, and a wide range of uses such as molded products by injection molding, sheets and films are expected in the future, but the crystallization rate is even faster. Materials are also expected to meet the needs of a wide range of customers in the future.

 On the other hand, there are few studies on improving the crystallization rate of aliphatic polyester, and generally, improvement is mainly made with inorganic fillers, and almost no improvement has been seen with resin compositions. In particular, there are almost no known examples for improving the crystallization rate by the resin composition with respect to polydaricholic acid. Disclosure of the invention

 The present invention provides a polyacetal resin composition comprising a polyacetal resin (a) and a polyester resin (b) and satisfying the following requirements (I) or (I I):

(I) Polyacetal resin (a) Polyester resin in which ethylene succinate unit or butylene succinate unit occupies 70 to 100 mol% of the main chain with respect to 100 parts by weight Fat (b) including 0.5 to 100 parts by weight,

 (II) Polyacetal resin (a) Polyglycolic acid-based polyester resin (b ') containing 100 parts by weight of darlicolic acid units occupying 70 to 100 mol% of the main chain with respect to 0.5 to 100 parts by weight Including. Detailed Description of the Invention

 Hereinafter, the present invention will be described as the invention (I) or (I I) according to the requirement (I) or (I I).

Invention (I)

 In view of the actual situation, an object of the present invention is to provide a polyacetal resin composition and a molded product excellent in dimensional stability and impact resistance.

 As a result of diligent research to achieve the above object, the present inventors have found that the above-mentioned problems can be solved by a resin composition and a molded product obtained by blending a specific polyester resin with a polyacetal resin, and completed the present invention. It came to do.

 That is, the present invention is based on 100 parts by weight of the polyacetal resin (a), and 0.1 to 100 parts by weight of the polyester resin (b) in which the ethylene succinate unit or the butylene succinate unit occupies 70 to 100 mol% of the main chain. A polyacetal resin composition, and

 The present invention relates to a molded article formed by molding the polyacetal resin composition, particularly a molded article in which the polyester resin (b) is dispersed with an equivalent circle diameter of 1,0 m or less.

 According to the present invention, it becomes possible to provide a resin composition and a molded product excellent in dimensional stability and impact resistance characteristics, and it is possible to further improve the quality of the polyacetal resin.

Hereinafter, the present invention will be described in detail. The polyacetal resin (a) used in the present invention is a polymer compound having an oxymethylene group (one CH ₂ 0—) as a main structural unit. It may be any one of oxymethylene homopolymers, copolymers containing other structural units in addition to oxymethylene groups (including block copolymers), etc., and the molecule has not only a linear structure but also a branched or crosslinked structure. May be.

 In general, homopolymers are produced by polymerization of anhydrous formaldehyde or trioxane, a cyclic trimer of formaldehyde. It is usually stabilized against thermal decomposition by terminal cap.

The copolymer is generally formaldehyde or a cyclic oligomer of formaldehyde represented by the general formula ((: ()) _n (where n is an integer of 3 or more), for example, trioxane, cyclic ether and / or cyclic formal. In general, the polyacetal resin (a) used in the present invention is stabilized against thermal decomposition by removing the unstable portion at the end by hydrolysis. From the viewpoint of the stability of the hue of the resin composition to be prepared and the molded product thereof, a polyacetal resin copolymer is particularly preferable.

 The trioxane used as the main raw material for the polyacetyl resin copolymer is generally obtained by reacting an aqueous formaldehyde solution in the presence of an acidic catalyst, and is purified by a method such as distillation. The trioxane used for polymerization is preferably one containing as little impurities as possible, such as water, methanol and formic acid.

In the production of the polyacetal resin copolymer, cyclic ethers and Z or cyclic formal compounds used as comonomers include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, oxetane, tetrahydrofuran, trioxepane, 1,3-dioxolane, ethylene Examples include glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal, 1,5-pentanediol formal, 1,6-hexanediol formal, and the like. Among them, ethylene oxide, 1,3-dioxolane, 1,4-bub One type or two or more types selected from the group consisting of tandiol formal and jetylene glycol formal are preferable, and 1,3-dioxolan is particularly preferable. The particularly preferred copolymerization ratio of these cyclic ethers and / or cyclic formal compounds is 0.5 to 20% by weight.

 The polyacetal resin copolymer is generally obtained by a method in which an appropriate amount of molecular weight modifier is further added and cationic polymerization is performed using a cationic polymerization catalyst. Examples of the molecular weight regulator include low molecular weight acetal compounds having an alkoxy group such as methylal, methoxymethylal, dimethoxymethylal, trimethoxymethylal, oxymethylenedi-n-butyl ether, methanol, ethanol, butanol, etc. Alcohols, ester compounds, acid compounds, water and the like. Among them, a low molecular weight acetal compound having an alkoxy group is particularly preferable.

Cationic polymerization catalysts used in the production of the polyacetal resin copolymer include lead tetrachloride, tin tetrachloride, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony trichloride, phosphorus pentafluoride, pentafluoride. Trifluoride such as antimony trifluoride, boron trifluoride, boron trifluoride jetyl etherate, boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride atomic anhydrate, boron trifluoride triethylamine complex Boron coordination compounds, Perchloric acid, Acetyl perchlorate, t-Butyl monochloroate, Hydroxyacetic acid, Trichlorodiacetic acid, Trifluoroacetic acid, Trifluoromethanesulfonic acid, p-toluenesulfonic acid, and other inorganic and organic acids, Triethyloxy Umte Complex salt compounds such as rough mouth roborate, triphenylmethylhexafluoroantimonate, allyldiazonium hexafluorophosphine, allyldiazoniumtetrafolate, etc., jetylzinc, triethylaluminum, jetylalum And alkyl metal salts such as heteroboric acid and isopolyacid. Among them, especially boron trifluoride, boron trifluoride Jetle Teller, Boron trifluoride coordination compounds such as boron trifluoride dibutyl etherer, boron trifluoride dioxanate, boron fluoride acetane hydrate, and boron trifluoride triethylamine complex are preferred. These catalysts can also be used after diluting with an organic solvent or the like.

 In the production of the polyacetal resin copolymer, the polymerization apparatus is not particularly limited, and a known apparatus is used, and a continuous polymerization apparatus with a biaxial paddle or the like is particularly preferably used. The polymerization temperature is preferably kept at 65 to 135. The deactivation after the polymerization is performed by adding a basic compound or an aqueous solution thereof to the product reaction product discharged from the polymerization machine after the polymerization reaction, or the reaction product in the polymerization machine. Basic compounds for neutralizing and deactivating the polymerization catalyst include ammonia, amines such as trytylamine, tryptylamine, triethanolamine, tributylamine, or aluminum, metal, and alkaline earth. Metal hydroxide salts and other known catalyst deactivators are used. Further, after the polymerization reaction, it is preferable to quickly add these aqueous solutions to the product to deactivate them. After the polymerization method and the deactivation method, washing, separation and recovery of unreacted monomers, drying, and the like are further performed by a conventionally known method as necessary.

 The melt index of the polyacetal resin (a) of the present invention is preferably in the range of 0.01 to 500 g / lOmin, particularly preferably in the range of 0.1 to 100 g / 10 min.

Next, as a method for producing a polyester resin (b) in which the ethylene succinate unit or butylene succinate unit used in the present invention occupies 70 to 100 mol% of the main chain, succinic acid or a derivative thereof (dimethyl succinate) Succinic acid esters such as succinic acid succinic acid, succinic anhydride) and ethylene glycol or 1,4-butanediol, (ii) ring-opening polymerization with succinic anhydride and ethylene oxide, etc. Is exemplified. The polyester resin (b) used in the present invention may contain an ethylene succinate unit or a unit other than a butylene succinate unit in a range not exceeding 30 mol%, and the production of the above (i) In the method of (ii), polycondensation using a dicarboxylic acid component other than succinic acid or its derivative, or a diol component other than ethylene glycol or 1,4-butanediol, It can be obtained by a ring-opening polymerization method using a part of an acid anhydride other than succinic anhydride or a cyclic ether component other than ethylene oxide.

 In (1), dicarboxylic acid components other than succinic acid or its derivatives include oxalic acid, malonic acid, dartaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, tun Aliphatic dicarboxylic acids having a linear or branched alkylene group such as decanedicarboxylic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, 3,3-dimethylpentanedicarboxylic acid, dimer acid, maleic acid, Aliphatic dicarboxylic acids with unsaturated bonds such as itaconic acid and citraconic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, fuuric acid, isofuric acid, telelatalic acid, 2,6-naphthalene range Naphthenic dicarboxylic acids such as carboxylic acids, 4,4'-diphenyldicarboxylic acid, 4,4, -diphenyloxy Rujikarubon acid, 4, 4 '- diphenylmethane dicarboxylic acid, 4, 4' aromatic dicarboxylic acids such as Jifue two Le ketone dicarboxylic acid, and these Cal Bonn acid esters, acid anhydrides and the like. Among these, adipic acid, terephthalic acid, and carboxylic acid esters and acid anhydrides thereof are preferable. These dicarboxylic acid components can be used alone or in combination of two or more, and the amount used is 0 to 30 mol% of the whole dicarboxylic acid component.

In (i), the diol component other than ethylene glycol or 1,4 monobutanediol includes, for example, ethylene glycol (when 1,4-butanediol is the main composition), 1,4 monobutanediol (ethylene Glycol is the main composition), 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,2-pentanediol 2,4-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,2-hexanediol, neopentyldaricol , Fatty acids having linear or branched alkylene groups such as 3-methyl-1,5-pentanediol, 2,2-jetyl-1,3-propanediol, diethylene glycol, triethylene glycol, dipropylene glycol, etc. Long-chain aliphatic diols such as polyethylene diols, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. To Cyclohexanedicarboxylic alicyclic Jio le such as methanol and the like. These diol components can be used alone or in combination of two or more, and the amount used is 0 to 30 mol% of the whole diol component.

In addition to the above compounds, oxycarboxylic acids, cyclic esters, carbonic acid ester compounds and the like can also be used as a part thereof. Specific examples of oxycarboxylic acids include lactic acid, glycolic acid, 2-methyllactic acid, 3-hydroxypropionic acid, 3-hydroxy-1,2-dimethylpropionic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxy Butyric acid, 2-hydroxy-1-3-methylbutyric acid, 3-hydroxy-3-methyl-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6- Examples include hydroxycaproic acid, 2-hydroxyisocabronic acid, lactone ring-opened products, and carboxylic acid esters thereof. Specific examples of cyclic esters include glycolide, lactide, / 3-propiolactone, i3-ptyrolactone, pivalolactone,) 3-methyl-1-] 3-propiolactone,] 3-methyl-δ-valerolactone, <5 _ Valerolacton, ε-force prolactone, etc. Specific examples of carbonate compounds Examples thereof include dimethyl carbonate, jetyl carbonate, dibutyl carbonate, diphenyl carbonate, and ethylene carbonate. These oxycarboxylic acid, cyclic ester, and carbonate ester compound components can be used alone or in combination of two or more thereof, and the amount used is 0 to 30 mol% of the total amount of ester or carbonate 卜 units. .

 It is also possible to use a small amount of an oxycarboxylic acid having at least three hydroxyl groups and carboxyl groups, such as malic acid, citrate, and tartaric acid, and alkyl esters thereof. It is also possible to use a small amount of trihydric or higher alcohols such as trimethylolpropane and pen erythritol.

 Furthermore, when an optical isomer exists in the above compound, any of D-form, L-form, and racemate may be used.

In (ii), examples of the cyclic ether component other than ethylene oxide include propylene oxide, cyclohexene oxide, styrene oxide, epichlorohydrin, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ester. 1 ter, phenyldaricidyl ether, tetrahydrofuran, oxetane and the like. These cyclic ether components can be used alone or in combination of two or more, and the amount used is 0 to 3 mol% of the entire cyclic ether component. Further, in (ii), an acid anhydride other than succinic anhydride, a dicarboxylic acid, a diol, an aliphatic oxycarboxylic acid, a cyclic ester, a carbonic acid ester compound, etc. may be used as a part thereof. The polymerization of the polyester resin (b) in which the ethylene succinate unit or butylene succinate unit of the present invention occupies 70 to 100 mol% of the main chain is usually carried out in the presence of a catalyst. The catalysts can be used alone or in combination of two or more. The polymerization catalyst is not particularly limited. Titanium, zirconium, hafnium, vanadium, manganone, iron, cobalt, nickel, zinc, aluminum, gallium, iridium, gem Rumanium, tin, antimony, lithium, sodium, cesium, magnesium, .compounds containing elements such as calcium, barium, lanthanum, samarium, for example, organic acid salts, metal alkoxides, metal complexes (such as acetyl chloride toner) Organometallic compounds such as metal oxides, metal hydroxides, carbonates, phosphates, sulfates, nitrates, chlorides and other inorganic metal compounds, triarylamine, triethylamine, tri-n-octylamine, benzyldimethylamine Tertiary amines such as phosphoric acid, phosphomolybdic acid, heteropolyacids such as key tungstic acid and their alkali metal salts, sulfuric acid, p_toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, 1-propanesulfone Acid, benzenesulfonic acid, p-black Zen sulfonic acid, m- xylene - protonic acid or a derivative thereof such as 4-sulfonic acid.

 An organic or inorganic phosphorus compound can be used in combination with the metal compound catalyst. Specific examples include phosphoric acid, phosphoric anhydride, polyphosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, hypophosphorous acid, tripolyphosphoric acid and their metal salts, ammonium salts, chlorides. , Esterified products, alkyl or aryl acid phosphates, methylphosphonic acid, ethylphosphonic acid, phenylphosphonic acid, naphthylphosphonic acid, dibutylbutylphosphonate, dibutylhydrogen phosphite, tridecylphosphite, triphenylphosphite, diphenylisodecylphosphite, And trisisodecyl phosphite.

Furthermore, after ring-opening polymerization with succinic anhydride and ethylene oxide, the molecular weight is increased in the molten state under reduced pressure.〗 P-A 8— 3 4 8 4 3, JP-A 1 1- JP 1-A 4-1 8 9 8 2 2, JP-A 4— 1 8 9 8 2 3, JP-A 6— 4 1 2 8 8, JP-A 6— 2 9 8 9 2 0, JP-A 7— 5 3 7 0 0, JP-A 7— 7 0 2 9 6, JP-A 7— 9 0 0 4 3 Increase molecular weight with isocyanate compounds such as hexamethylene diisocyanate Or a method for increasing the molecular weight with an epoxy compound, an aziridine compound, an oxazoline compound, a polyvalent metal compound, a phosphate ester, a phosphite ester, a polyvalent carboxylic acid, a polyvalent acid anhydride, etc., US-A It is also possible to carry out a dehydration condensation reaction using an organic solvent, such as 5, 401, 796. It is also possible to carry out a transesterification reaction with other polymers under heating.

 The weight average molecular weight (Mw) of the polyester resin (b) in which the ethylene succinate unit or the butylene succinate unit of the present invention occupies 70 to 100 mol% of the main chain is from 10,000 to 1,000,000. The range is preferable, and the range of 20,000 to 500,000 is particularly preferable. The weight average molecular weight (Mw) is a value calculated by using a polymethyl methacrylate as a standard, which was determined by a GPC measuring device as described later in Examples.

 In the present invention, a resin composition is prepared using the polyacetal resin (a) and a polyester resin (b) in which the ethylene succinate unit or the butylene succinate unit occupies 70 to 100 mol% of the main chain. The composition ratio of (a) and (b) is as follows: Polyacetal resin (a) Polyester resin (b) in which ethylene succinate units or butylene succinate units account for 70 to 100 mol% of the main chain with respect to 100 parts by weight It must be ~ 100 parts by weight. Polyacetal resin (a) When 100 parts by weight is less than 0.5 parts by weight of polyester resin (b), where ethylene succinate units or butylene succinate units occupy 70 to 100 mol% of the main chain Sufficient improvement in resistance and impact resistance cannot be obtained.

The composition preparation method of the present invention is not particularly limited. Basically, the polyacetal resin (a) and a polyester resin in which ethylene succinate units or butylene succinate units occupy 70 to 100 mol% of the main chain ( b) is prepared by melt kneading. It is desirable that the processing conditions are kneading at a temperature of not less than the melting points of (a) and (b), preferably 175T: not less than 250 ° C and not less than 30 seconds. Preparation method There is no particular limitation on the specific state, and in general, it can be prepared by a known equipment and method as a method for preparing a synthetic resin composition. That is, mix the necessary ingredients,

A kneading method using a single-screw or twin-screw extruder or other melt-kneading apparatus is common. In addition, in order to improve the dispersion and mixing of each component, a part or all of the resin component is finely pulverized, mixed and melt-extruded, and then a pellet is formed, or a part of the components constituting the composition is previously added. It is also possible to use a method of melt kneading (master batch) and further kneading this with the remaining other components to obtain a composition of a predetermined component or a molded product. In addition, the composition of the present invention exhibits excellent dimensional stability as it is, but it can be stabilized by heat treatment at an appropriate temperature after the composition is prepared.

The resin composition of the present invention can further contain various known stabilizers. Examples of the antioxidant used in the composition of the present invention include phenolic (such as hindered phenols), amines (such as hindered amines), phosphorus, rhodium, hydroquinone, and quinoline antioxidants. Agents and the like.

 Examples of phenolic antioxidants include hindered phenols such as 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-methylenbis (2,6-di-t_butyl). Phenol, 4, 4, -butylidenebis (3 monomethyl _ 6- t -butylphenol), 2, 6-di- t -butyl- p-cresol, 1, 3, 5-trimethyl-2, 4, 6-tris (3,5-di-t-butyl-l-hydroxybenzyl) benzene, 1,6-hexanediol-bis [3—

(3,5-di-t-butyl-1-hydroxyphenyl) propionate], Pen Eris! ^ 1-tetrakis [3— (3, 5-di-t —butyl-4-hydroxyphenyl) propionate], triethylene glycol monobis [3— (3-t-butyl 1-methyl-4-hydroxyphenyl) propionate ], N-octadecyl-3— (4,, 5′-di-t_butylphenol) propionate, n— Octadecyl 3- (4'-hydroxy-3,, 5'-di-tert-butylphenol) propionate, stearyl-2 ((3,5-di-t-petite 4-hydroxyphenol) propionate, distearyl-3, 5 —Di—t-butyl—4 —hydroxybenzylphosphonate, 2— t _butyl— 6_ (3— t-butyl

5-methyl-2-hydroxybenzyl) _4_methylphenyl acrylate, N, N '—hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-monohydrocinnamamide), 3,9-bis {2— [ 3- (3-t-butyl-4-hydroxy-1-5-methylphenyl) propionyloxy] 1,1,1-dimethylethyl} 1,2,4,8,10 0-tetraoxaspiro [5,5] undecane, 4, 4 '—Chobis

(3-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenol) butane.

 Examples of amine-based antioxidants include hindered amines such as tri- or tetra-C 1-3 alkylpiperidine or derivatives thereof [eg, 4-methoxy-2, 2, 6,

6-tetramethylpiperidine, 4-benzoyloxy-2, 2, 6, 6-tetramethylbiperidine, 4-phenoxy-1,2,2,6,6-tetramethylpiperidine, etc.], bis (tri, tetra or pen Alkyl piperidine) C 2-20 alkylene dicarboxylic acid ester [for example, bis (2, 2, 6, 6-tetramethyl-4-piperidyl) ogisalate, bis (2, 2, 6, 6-tetramethyl-4-piperidyl) ) Malonate, bis (2, 2, 6, 6-tetramethyl-4-piperidyl) adipate, bis (2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate, bis (1, 2, 2, 6, 6-Pen evening methyl 4-piperidyl) Sebacate, bis (2, 2, 6, 6-tetramethyl 4-piperidyl) terephthalate], 1, 2_bis (2, 2, 6, 6 —Tetramethyl-4-piperidyloxy) ethane, Phenyl- 1 naphthylamine, phenyl-2 naphthylamine, N, N '— Diphenyl-1, 4-phenyldiamine, N-phenylil N' — cyclohexyl 1, 4 1 and 2 range amines.

 Phosphorus antioxidants include, for example, triisodecyl phosphite, trisnonyl phenyl phosphite, diphenyl isodecyl phosphite, phenyl sodecyl phosphite, 2,2-methylene bis 1-butylphenyl) octyl phosphite, 4, 4, —butylidenebis (3-methyl-6-t-butylphenyl) ditridecyl phosphite, 卜 ris (branched C3-6 alkylphenyl) phosphite [eg, tris (2, 4-di-t-butylphenyl) phosphite, tris (2-tert-butyl-4 monomethylphenyl) phosphite, tris (2,4-di-t-amylphenyl) phosphite, tris (2-tert-butylphenyl) Phosphite, Tris [2— (1,1-Dimethylpropyl) monophenyl] Phosphite, Tris [2, 4 -(1, 1-dimethylpropyl) -phenyl] phosphite, etc.], bis (2-t_butylphenyl) phenyl phosphite, tris (2-cyclohexylphenyl) phosphite, tris (2-t_butyl- 4-phenylphenyl) phosphite, bis (C3-9 alkylaryl) pen erythritol diphosphite [eg, bis (2,4-di-t-butyl_4 monomethylphenyl) pen erythritol diphosphite, bis (2 6-Gee t-Butyl-4-methylphenyl) Pentaerythri! ^ One Rudiphosphite, Bis

(Nonylphenyl) pen erythritol diphosphite, bis (nonylphenyl) pen erythritol diphosphite, etc.], triphenyl phosphate stabilizers (for example, 4-phenoxy-9-one (4-hydroxyphenyl) ) _P_ cumenyloxy 3, 5, 8, 10—tetraoxa-1,9-diphosphapyro [5,5] undecane, tris (2,4-di-tert-butylphenyl) phosphate, etc.), diphosphonite stabilizers (eg tetrakis (2, 4_G t 1 ptyl) 1, 4, 4'-biphenyl dirange phosphonite, etc.).

Examples of hydroquinone antioxidants include 2, 5 Examples include quinoline antioxidants such as 6-ethoxy 2,2,4, -trimethyl-1,2-dihydroquinoline, and thio antioxidants. Examples thereof include dilauryl thiodipropionate and distearyl thiodipropionate.

 These antioxidants can be used alone or in combination of two or more. The content of the antioxidant is, for example, from 0.1 to 5 parts by weight, preferably from 0.05 to 2.5 parts by weight, particularly from 0.1 to 0.1 parts by weight based on 100 parts by weight of the resin composition. It can be selected from a range of about 1 part by weight.

 Examples of the heat stabilizer used in the resin composition of the present invention include metal hydroxides and inorganic salts, fatty acid metal salts, nitrogen-containing compounds such as amidine compounds and amide compounds, and the like. In general, benzotriazole substances, benzophenone substances, aromatic benzoate substances, hindered amine substances (piperidine derivatives having a sterically hindered group) and the like are generally used.

 Furthermore, various known additives can be blended in the composition of the present invention in order to improve its physical properties according to the intended use. Examples of additives include various colorants, lubricants, mold release agents, nucleating agents, surfactants, heterogeneous polymers, organic polymer modifiers and inorganic, organic, metallic and other fibrous materials, powders, boards These fillers can be used, and one or more of these can be used in combination.

 In addition, the above-mentioned stabilizer, additive, etc. can be blended at any desired level, for example, once added to the polyacetal resin (a), the ethylene succinate unit or butylene succinate unit is 70 to 100 mol% of the main chain. Once added to the polyester resin (b), or the resin composition

It can be added at the time of adjustment, and can be added and mixed immediately before obtaining the final molded product.

The resin composition of the present invention obtained by the above method comprises an injection molding method, a gas assist gun It is formed into a molded product by applying conventionally known molding methods such as extrusion molding, extrusion molding, blow molding, sheet molding, and film molding.

A molded article using the composition of the present invention comprises a polyacetal resin (a) and a polyester resin in which the ethylene succinate unit or the butylene succinate unit occupies 70 to 100 mol% of the main chain (b) ). In this case, the polyester resin (b) is preferably dispersed with the following equivalent circle diameter, and particularly preferably 0.5 m or less. Here, the equivalent circle diameter is evaluated by the method described later in Examples. When the polyester resin (b) is dispersed with an equivalent circle diameter exceeding l.O / ^ m, the improvement effect on the dimensional stability and impact resistance is small, which is not preferable.

 A molded article using the resin composition of the present invention obtained as described above is excellent in dimensional stability and impact resistance, and can further improve the quality of the polyacetyl resin. The mechanism is not clear, but an ethylene succinate resin or a butylene succinate resin that is well finely dispersed and highly compatible with polyacetylene resin works well. It is guessed. (Invention U I)

 Invention (II) includes a polyacetal resin (a) and a polyester resin (b ′), wherein the glycolic acid unit is a main chain with respect to the polyacetal resin (a) 0.5 parts by weight or more and less than 100 parts by weight. It is a polyacetal resin composition containing 100 parts by weight of a polyglycolic acid-based polyester resin (b ′) occupying 70 to 100 mol%. In other words, it is a polyglycolic acid polyester resin composition containing the above (a) and (b ′). In view of the actual situation, an object of the present invention is to provide a polydaricholic acid-based polyester resin composition having an improved crystallization rate.

As a result of intensive studies to achieve the above object, the present inventors have found that a specific resin composition can solve the above-mentioned problems, and have completed the present invention. That is, the present invention provides a polyacetal resin (a) 0.5 parts by weight or more and 100 parts by weight with respect to 100 parts by weight of a poly (dallycolic acid) polyester resin (b ′) in which glycolic acid units occupy 70 to 100 mol% of the main chain. It is related with the polyester resin composition formed by mix | blending less. According to the present invention, it is possible to provide a resin composition having an improved crystallization rate and improved quality of a polyglycolic acid polyester resin.

 Hereinafter, the present invention will be described in detail. The production method of the polyglycolic acid-based polyester resin (b ′) in which the glycolic acid unit used in the present invention occupies 70 to 100 mol% of the main chain includes (i) glycolide which is a cyclic dimer ester of glycolic acid. And a method by polycondensation of glycolic acid and / or a carboxylic acid ester thereof, and the like. The glycolide used in the above (i) can be obtained by a sublimation depolymerization method or a solution phase depolymerization method of a glycolic acid oligomer, and it is particularly preferable to use glycolide having a high purity.

Here, the glycolic acid unit is represented by _O 1 CH ₂ —CO— and can also be referred to as an oxymethylene force sulfonyl unit.

 The polyester resin (b ′) used in the present invention may contain units other than glycolic acid units in a range not exceeding 30 mol%, and in the production method (i) above, other than darlicolide. Components other than glycolic acid and / or its carboxylic acid ester may be used as part of the reaction component in the production method of i). Examples of other components mentioned here include a dicarboxylic acid component, a diol component, an oxycarboxylic acid component, a cyclic ester component, and a carbonate ester compound component. These components may be used alone or in combination of two or more. it can.

Examples of the dicarboxylic acid component include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid , Ok Unsaturated bonds such as aliphatic dicarboxylic acid having a linear or branched alkylene group such as dicarboxylic acid, 3,3-dimethylpentanedicarboxylic acid, dimer acid, maleic acid, itaconic acid, citraconic acid Aliphatic dicarboxylic acid having a cycloaliphatic acid, alicyclic dicarboxylic acid such as cyclohexane dicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid such as 2,6-naphthalenedicarboxylic acid, 4, 4'- Diphenyl dicarboxylic acids, 4,4'-diphenoxyether dicarboxylic acids, 4,4'-diphenylmethane dicarboxylic acids, aromatic dicarboxylic acids such as 4,4'-diphenyl ketone dicarboxylic acids, and their carboxylic acids Examples include acid esters and acid anhydrides.

 Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 2,3— Butanediol, 1,5_pentanediol, 1,2-pentanediol, 2,4-pentanediol, 1,6-hexanediol, 1,7_heptanediol, 1,8-octanediol, 1, 9-nonanediol, 1,2-hexanediol, neopentyldarlicol, 3 monomethyl-1,5, -pentanediol, 2,2-jetyl-1,3-propanediol, diethylene glycol, triethylene glycol, di Aliphatic diols having a linear or branched alkylene group such as propylene glycol, polyethylene glycol, polypropylene glycol , Long-chain aliphatic diols of polytetramethylene glycol, 1, 4 Shikuro Cyclohexanedicarboxylic methanol alicyclic di-ols such like to.

Specific examples of the oxycarboxylic acid component include lactic acid, 2-methyllactic acid, 3-hydroxypropionic acid, 3-hydroxy-1,2-dimethylpropionic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, and 4-hydroxybutyric acid. 2-hydroxy-3-methylbutyric acid, 3-hydroxy-3-methylbutyric acid, 2-hydroxy-3, 3-dimethyl Examples include butyl butyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycabronic acid, 2-hydroxyisocabronic acid, lactone ring-opened products, and carboxylic acid esters thereof. .

 Specific examples of the cyclic ester component include lactide, 3-propiolactone, β-ptyrolactone, pivalolactone, / 3-methyl-] 3-propiolactone, / 3-methylone <5-valerolactone, δ-valerolactone , Ε-force prolactone and the like. Specific examples of the carbonate compound include dimethyl carbonate, dimethyl carbonate, dibutyl carbonate, diphenyl carbonate, and ethylene carbonate.

 It is also possible to use a small amount of an oxycarboxylic acid having at least three or more hydroxyl groups and carboxyl groups, such as malic acid, citrate, and tartaric acid, and alkyl esters thereof. Also, trimethylolpropane, pen evening erisuri! It is also possible to use a small amount of trihydric or higher alcohol such as one.

 Furthermore, when an optical isomer exists in the above compound, any of D-form, L-form, and racemate may be used.

The polymerization of the poly (dalycolic acid) polyester resin (b ′) in which the glycolic acid unit used in the present invention accounts for 70 to 100 mol% of the main chain is usually carried out in the presence of a catalyst. The catalysts can be used alone or in combination of two or more. The polymerization catalyst is not particularly limited. Titanium, zirconium, hafnium, vanadium, manganese, iron, cobalt, nickel, zinc, aluminum, gallium, iridium, germanium, tin, antimony, lithium, sodium, cesium, magnesium, Compounds containing elements such as calcium, barium, lanthanum, samarium, for example, organic metal compounds such as organic acid salts, metal alkoxides, metal complexes (acetylacetate, etc.), metal oxides, metal hydroxides, carbonic acid Inorganic metal compounds such as salts, phosphates, sulfates, nitrates, chlorides, triarylamine, triethylamine, tri-n-octylami , Tertiary amines such as benzyldimethylamine, phosphotungstic acid, phosphomolybdenic acid, heteropolyacids such as key tungstic acid and their alkali metal salts, sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, Examples thereof include protonic acids such as 1-propane sulfonic acid, benzene sulfonic acid, p-chloro benzene sulfonic acid, m_xylene-4-sulfonic acid, and derivatives thereof. An organic or inorganic phosphorus compound can be used in combination with the above metal compound catalyst. Specific examples include phosphoric acid, anhydrous phosphoric acid, polyphosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, hypophosphorous acid, tripolyphosphoric acid and their metal salts, ammonium salts, chlorides. , Esterified products, alkyl or aryl acid phosphates, methylphosphonic acid, ethylphosphonic acid, phenylphosphonic acid, naphthylphosphonic acid, dibutylbutylphosphonate, dibutylhydrogen phosphite, tridecylphosphite, triphenylphosphite, diphenylisodecylphosphite, And trisisodecyl phosphite.

 Furthermore, JP-A 4— 1 8 9 8 2, JP-A 4— 1 8 9 8 2, JP-A 4— 1 8 9 8 2 2, JP-A 4— 1 8 9 8 2 3, J PA 6-4 1 2 8 8, JP-A 6— 2 9 8 9 2 0, JP-A 7— 5 3 7 0 0, JP-A 7 1 7 0 2 9 6, JP-A 7-9 0 0 4 3, a method for increasing the molecular weight with an isocyanate compound such as hexamethylene diisocyanate, or an epoxy compound or an aziridin compound , An oxazoline compound, a polyvalent metal compound, a phosphoric acid ester, a phosphorous acid ester, a polyvalent carboxylic acid, a polyhydric acid anhydride, etc., a method for increasing the molecular weight, such as US-A 5 4 0 1 7 9 6, organic It is also possible to perform a dehydration condensation reaction using a solvent. It is also possible to carry out a transesterification reaction with other polymers under heating.

The weight average molecular weight (Mw) of the polyglycolic acid polyester resin (b ′) in which the glycolic acid unit used in the present invention occupies 70 to 100 mol% of the main chain is 10,000 to 1,0. Those in the range of 00,000 are preferred, and those in the range of 20,000 to 500,000 are particularly preferred. The weight average molecular weight (Mw) is a value calculated by using a polymethyl methacrylate as a standard, which was determined by a GPC measuring device as described later in Examples.

The polyacetal resin (a) used in the present invention is as described in the above invention (I). However, as the cyclic ether and / or cyclic formal compound used in the production of the polyacetal resin copolymer, ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epiphine mohydrin, styrene oxide, oxetane, 3, 3-bis (chloromethyl) oxetane, tetrahydrofuran, trioxepane, 1,3-dioxolan, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4 dibutanediol formal, 1,5-pentanediol Formal, 1, 6-hexanediol formal and the like. Among these, one or more selected from the group consisting of ethylene oxide, 1,3-dioxolan, 1,4-butanediol formal, and diethylene glycol formal are preferable, and 1,3-dioxolane is particularly preferable. A particularly preferred copolymer composition of these cyclic ethers and / or cyclic formal compounds is 0.5 to 20% by weight.

 In the present invention, a resin composition is prepared using the polyglycolic acid-based polyester resin (b ′) in which the glycolic acid unit occupies 70 to 100 mol% of the main chain and the polyacetal resin (a). The composition ratio of (a) and (b ′) is such that the polyacetal resin (a) is 0.5 parts by weight or more and less than 100 parts by weight with respect to 100 parts by weight of the polyester resin (b). In particular, the polyacetal resin (a) is preferably 1 to 50 parts by weight. When the amount of the polyacetal resin (a) is less than 0.5 parts by weight with respect to 100 parts by weight of the polyester resin (b ′), the improvement of the crystallization rate is small.

The method for preparing the composition of the present invention is not particularly limited, but is basically polyester. The resin (b ′) and the polyacetal resin (a) are prepared by melt-kneading the components. The treatment conditions are preferably kneaded for at least 30 seconds at a temperature not less than the melting points of (b ') and (a), preferably not less than 210 and not more than 250 ° C. The specific embodiment of the preparation method is not particularly limited, and can be generally prepared by a known equipment and method as a preparation method of the synthetic resin composition. That is, a general method is to mix necessary components and knead them using a single or twin screw extruder or other melt kneading apparatus. In addition, in order to improve the dispersion and mixing of each component, a part or all of the resin component is finely pulverized, mixed and melt-extruded, and then a method of forming the pellet, or a part of the components constituting the composition is previously prepared. It is also possible to use a method of melt-kneading (master batch) and further kneading this with the remaining other components to obtain a composition of a predetermined component or a molded product.

 The resin composition of the present invention can further contain various known stabilizers. In particular, it is particularly preferable to add an antioxidant from the viewpoint of the stability of the hue of the resin composition pellets and Z or the molded product. Examples of the antioxidant used in the composition of the present invention include phenol-based (such as hindered phenols), amine-based (such as hindered amines), phosphorus-based, xio-based, hydroquinone-based, quinoline-based antioxidants. Etc. Specific examples thereof are the same as those in the invention (I). In addition, the above-mentioned stabilizers, additives and the like can be added at any stage, for example, once added to the polyester resin (b ′), once added to the polyacetal resin (a), or the resin composition. It may be added at the time of preparation, or may be added and mixed immediately before obtaining the final molded product.

 The polyglycolic acid-based polyester resin composition of the present invention obtained as described above has an improved crystallization speed and can further improve the quality.

In particular, the polyester resin composition preferably has a temperature difference (Tm−T c) between its melting point (Tm) and crystallization temperature (T c) of 35 t: or less. Where Tm, T c Is the melting point and crystallization temperature measured by DSC (differential scanning calorimetry), as will be described later in the examples. The smaller (Tm-T c), the faster the crystallization rate of the resin composition. .

 The resin composition of the present invention can be applied to conventionally known molding methods in various fields such as injection molding, extrusion molding, blow molding, sheet molding, film molding, and fiber molding. . Brief Description of Drawings

 FIG. 1 is an SEM observation photograph of the resin composition of Example 3. Example

 EXAMPLES Hereinafter, the present invention U) and (I I) will be specifically described by way of examples, but the present invention is not limited thereto. Invention (I)

Production Example 1 Preparation of polyacetal resin copolymer (a-1)

A jacket that passes a heat (cold) medium on the outside, a cross-section of a barrel that has a shape that partially overlaps two circles, and a continuous mixing reactor consisting of a rotating shaft with a paddle, and a paddle attached 2 While rotating the rotating shafts of each at 150 rpni, 100 parts by weight of trioxane, 3.2 parts by weight of 1,3-dioxolane, and 0.1 part by weight of methyl as a molecular weight regulator were continuously added at a predetermined ratio. In addition, bulk polymerization was carried out by continuously adding 0.002 part by weight of boron trifluoride as a catalyst. The reaction product discharged from the polymerizer was passed through a crusher quickly, and added to a 60 ° C aqueous solution containing 0.05% by weight of triethylamine to deactivate the catalyst. Furthermore, crude polyacetal resin was obtained after separation, washing and drying. Next, 3 parts by weight of a 5% by weight aqueous solution of triethylamine per 100 parts by weight of the crude polyacetal resin, and the stabilizer penicillary erythrityl-tetrakis [3- (3,5-di-tert-petite 4-hydroxyphenol] Enil) propionate] was added in an amount of 0.3 part by weight, and the kneaded mixture was melt-kneaded at 210 in a twin-screw extruder at 210 to remove the unstable part, thereby obtaining a pellet-like polyacetal resin copolymer (a-1). The obtained polymer had a melt index (measured at 190 ° C under a load of 2160 g in accordance with AS TM D- 1 2 3 8) of 9.5 gZ10 min. The copolymer composition was confirmed to be 3.4% by weight by proton NMR measurement using hexafluoroisopropanol d 2 as a solvent.

Production Example 2 Preparation of polyacetal resin homopolymer (a _ 2)

 Using the same continuous mixing reactor as in Production Example 1, while rotating two rotating shafts with paddles at 150 rpm each, trioxane 100 parts by weight and methylal as a molecular weight regulator 0.1 weight Part was continuously added at a predetermined ratio, and 0.002 part by weight of boron trifluoride as a catalyst was continuously added and fed to perform bulk polymerization. The reaction product discharged from the polymerizer was quickly passed through a crusher, and added to 60 aqueous solution containing 0.05% by weight of ligethylamine to deactivate the catalyst. Further, after separation, washing, and drying, a crude polyacetal resin was obtained.

 Then, using cyclohexane as a solvent and sodium acetate as a catalyst, this crude polyacetal and acetic anhydride were reacted at a temperature of 145 ° C. for 1 hour to stabilize the ends. Subsequently, for 100 parts by weight of the obtained polyacetal resin, 0.3 wt. Of penyu erythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] is used as a stabilizer. Partly added and melt-kneaded at 210 ° C. with a twin-screw extruder to obtain a pellet-like polyacetal resin homopolymer (a-2). The resulting polymer had a melt index (measured according to A S TM D — 1 2 3 8) of 12.2 gZ10 min.

Production Example 3 Preparation of polyethylene succinate resin (b-1) Nitrogen substitution was performed by adding 50.0 parts by weight of succinic anhydride and zirconyl succinate to the autoclave. Next, with stirring, the autoclave was gradually heated to 130 ° C to melt the succinic anhydride, and at the same temperature, 23.1 parts by weight of ethylene oxide was maintained while maintaining the pressure in the autoclave at about 5 kgi / cm ^2. Was introduced continuously over 5 hours. After introduction of ethylene oxide, the reaction was further carried out at 13 (T for 1 hour. The reaction product was cooled in a water bath and cut with a cutlet to obtain a pelleted polyethylene succinate resin (b-1). The weight average molecular weight of the obtained polymer was 41,000. The weight average molecular weight was measured by the following method.

 [Weight average molecular weight]

 Measurement was carried out at 40 ° C. by using a GPC measurement apparatus and using HFIP (hexafluoroisopropanol) ZlOmM sodium trifluoroacetate as an eluent. Polymethyl methacrylate was used as a standard sample.

Production Example 4 Preparation of polyethylene succinate resin (b-2)

 In a nitrogen atmosphere, a batch stirrer is charged with 32.3 parts by weight of ethylene glycol, 47.2 parts by weight of succinic acid, and manganese (II) acetate tetrahydrate as a catalyst. Under normal pressure, 145 to 220 The mixture was stirred at a temperature of ° C to conduct an esterification reaction. Subsequently, the reaction solution was transferred to a batch type stirring apparatus equipped with a double helical blade, tetra-n-butyl titanate and polyphosphoric acid were added as catalysts, and the reaction solution was stirred at a temperature of 220 ° C. under reduced pressure. The polycondensation reaction was carried out with stirring for 2 hours. The reaction product was discharged, cooled in a water bath, and cut with a cutter to obtain a pellet-shaped polyethylene succinate resin (b — 2). The weight average molecular weight of the obtained polymer was 54,000.

Production Example 5 Preparation of polybutylene succinate resin (b-3)

In a nitrogen atmosphere, a batch stirrer is charged with 36.25 parts by weight of 1,4-monobutanediol, 43.18 parts by weight of succinic acid, and tetraisopropyl titanate as a catalyst. Under normal pressure, 90 to 215 ° C The esterification reaction was carried out at a temperature of continue, The reaction solution was transferred to a batch stirrer equipped with a double helical blade, and the reaction solution was stirred at a temperature of 225 and stirred for 6 hours under reduced pressure to carry out a polycondensation reaction. The reaction product was discharged, cooled in a water bath, and cut with a cutter to obtain a pellet-shaped polybutylene succinate resin (b-3). The weight average molecular weight of the obtained polymer was 68,000.

Production Example 6 Preparation of polybutylene succinate-adipate copolymer resin (b-4) Under a nitrogen atmosphere, a batch stirrer similar to Production Example 3 was charged with 1,4 1-butanediol 34.8 parts by weight, succinic acid 34 6 parts by weight, 10.8 parts by weight of adipic acid (molar ratio of succinic acid to adipic acid 80:20), and tetraisopropyl titanate and phenylphosphonic acid as a catalyst were charged at 90 to 215 under normal pressure. The mixture was stirred at a temperature to conduct an esterification reaction. Subsequently, the reaction solution was transferred to a batch stirrer equipped with a double helical blade, and the reaction solution was stirred at a temperature of 220 ° C. and stirred under reduced pressure for 6 hours to carry out a polycondensation reaction. The reaction product was discharged, cooled in a water bath, and cut with a cutter to obtain pellets of polybutylene succinate and adipate copolymer resin (b-4). The weight average molecular weight of the obtained polymer was 47,000. The copolymer composition of adipic acid was confirmed to be 20 mol% based on the total acid by proton NMR measurement using hexafluoroisopropanol d2 as a solvent.

Production Example 7 Preparation of high molecular weight polybutylene succinate resin (b-5)

 Polybutylene succinate resin (b-3) obtained in Production Example 5 10.1 parts by weight of hexamethylene diisocyanate was added to 16.5 parts by weight, and 180-200 ° C for 1 hour. A high molecular weight reaction was performed. The reaction product was discharged, cooled in a water bath, and cut with a cutter to obtain a pellet-like high molecular weight polybutylene succinate resin (b-5). The weight average molecular weight of the obtained polymer was 144,000.

Examples 1-1 1 and Comparative Examples 1-4

As shown in Table 1, polyacetal resin (a-1, a-2) and polyester The resin (b-l to b-5) is mixed in advance, and then melted and kneaded at a resin temperature of 21 (T to prepare a pellet-like composition using a twin-screw extruder, followed by injection molding. ISO test specimens were molded using a machine, and the equivalent circle diameter, dimensional stability, and impact resistance characteristics of the dispersed particles were evaluated, and the results are shown in Table 1. For comparison, polyacetal resin (a-1) The same evaluation was performed for the case of using only No. 1. The results are also shown in Table 1.

 Each evaluation was carried out by the following method.

 [Evaluation of equivalent circle diameter of dispersed particles]

 An I S O tensile test piece was molded, and the central portion (surface perpendicular to the resin flow direction) of the test piece was cut with a diamond microtome. Subsequently, in order to remove the dispersed particles of the polyester resin, the cut surface was immersed in black mouth form at room temperature for 5 minutes, washed and dried, and then the observation surface was subjected to a sputtering process. The phase structure of the sample was observed with a scanning electron microscope (S E M), and the equivalent circle diameter (average value) of the dispersed particles was measured using an image processing device based on the observed image. For reference, an observation photograph by SEM of the resin composition of Example 3 is shown in FIG.

 [Evaluation of dimensional stability]

 I S O tensile test specimens were molded, and the specimens were left in an air-conditioned room at a temperature of 23 and a humidity of 50% for 24 hours, and then the dimensions (length in the longitudinal direction) of the specimens were measured accurately. Thereafter, the test piece was treated under the conditions of 70 ° C. × 2 hours, left again in the air-conditioned room for 24 hours, and the dimensions were measured. Based on the difference (absolute value) between the dimension after processing and the initial dimension, the dimensional stability was indicated by the following index.

 ◎ (very good): Dimensional change 0 mm or more ~ 0.

 ○ (Good): Dimensional change 0.0 3 or more ~ less than 0.05 mm

 △ (Slightly good): Dimensional change 0.05 to 匪-less than 0.1 删

 X (Inferior): Dimensional change 0.10 mm or more

[Evaluation of impact resistance] Charpy impact strength (notched) was measured based on I SOI 79/1 e A. Example:! To 14, Comparative Examples 1 to 4

As shown in Table 1, after mixing the polyacetal resin (a-1) and the polyester resin (b 1:! ~ 3) in advance, it was melt kneaded at a resin temperature of 170 ° C using a twin screw extruder. Then, a pellet-shaped composition was prepared, and then an ISO test piece was molded with an injection molding machine, and the equivalent-circle diameter, dimensional stability, and impact resistance of the dispersed particles were evaluated. The results are shown in Table 1.

Comparative Example 5

As shown in Table 1, after mixing polyacetal resin — 1) and polylactic acid resin (Lacia H-100J manufactured by Mitsui Chemicals), melt kneading at a resin temperature of 2 10 ° C using a twin screw extruder After processing, a pellet-like composition was prepared, and then an ISO test piece was molded by an injection molding machine, and the equivalent-circle diameter, dimensional stability, and impact resistance of the dispersed particles were evaluated. The results are shown in Table 1.

table 1

* Some hue change is seen in resin composition pellets and molded products.

Invention (I I)

Production Example 8 Preparation of polyglycolic acid resin (b-6)

Under a nitrogen atmosphere, the batch stirrer, glycolide 100 parts by weight, and, as a catalyst, were charged SnC · 6. 5Η ₂ 0, stirred for 2 hours to polycondensation reaction at a temperature of 1 75 ° C It was. The reaction product was discharged, cooled in a water bath, cut into a pellet by a cutter, and further dried under reduced pressure at 150 to obtain a polyglycolic acid resin (b-6). The weight average molecular weight of the obtained polymer was 55,000. The weight average molecular weight was measured by the following method.

 [Weight average molecular weight]

 Using a GPC measuring device, measurement was performed at 40 ° C. by using HF I P (hexafluoroisopropanol) / 1 OmM sodium trifluoroacetate as an eluent. Polymethyl methacrylate was used as a standard sample.

Production Example 9 Preparation of high molecular weight polyglycolic acid resin (b-7)

 The polymer obtained in Production Example 8 was subjected to solid phase polymerization at 210 ° C. under a reduced pressure of 0.1 lmbar for 25 hours to obtain a high molecular weight polyglycolic acid resin (b-7). The obtained polymer had a weight average molecular weight of 120,000.

Examples 15-18, Comparative Examples 6-8

 As shown in Table 2, polyester resin (b'-6, b'-7) and polyacetylene resin (a-1, a-2) were mixed in advance, and then, using a twin screw extruder, A melt-kneading treatment was carried out at a resin temperature of 225 ° C. to prepare a pellet-like composition, and then an ISO test piece was molded with an injection molding machine to evaluate the crystallization speed. The results are shown in Table 2. For comparison, the same evaluation was performed when only the polyester resin (b'-6) was used. The results are also shown in Table 2.

The crystallization rate was evaluated by the following method.

[Evaluation of crystallization rate] Samples of 1 Omg each were cut from each of the ISO tensile test pieces, and the DSC (Differential Scanning Calorimetry) was used to measure the temperature rise rate at 10T: / min · Cooling rate minus 10 at 10 min. ] (° C) and Tc [peak temperature of crystallization temperature] were measured, and Tm_Tc C) was calculated. still. When multiple Tm and Tc existed, the value on the high temperature side was used. The higher the Tc and the smaller the Tm-Tc, the faster the crystallization rate.

 Example 19

 As shown in Table 2, polyester resin (b'-1) and erythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] are not added. Polyacetal resin prepared as in Example 1

(a-1 ′) is mixed in advance, and then melt-kneaded at a resin temperature of 225 using a twin-screw extruder to prepare a pellet-like composition, followed by I SO using an injection molding machine. A test piece was molded and the crystallization rate was evaluated. The results are shown in Table 2. Table 2

 * Some hue change is seen in resin composition pellets and molded products.

Claims

The scope of the claims

1. A polyacetal resin composition comprising a polyacetal resin (a) and a polyester resin (b) that satisfies the following requirements (I) or (I I):

 (I) Polyacetal resin (a) Polyester resin in which ethylene succinate unit or butylene succinate unit occupies 70 to 100 mol% of the main chain with respect to 100 parts by weight (b) 0.5 to 100 parts by weight

-(I I) Polyacetal resin (a) 100 parts by weight of polydalicolate-based polyester resin (b ′) in which glycolic acid units occupy 70 to 100 mol% of the main chain with respect to 0.5 parts by weight or more and less than 100 parts by weight.

2. Polyacetal resin (a) Force Formaldehyde or general formula (CH ₂ 0) _n (where n is an integer of 3 or more) is copolymerized with cyclic oligomer of formaldehyde and cyclic ether and cyclic or cyclic formal. 2. The polyacetal resin composition according to claim 1, which is a polyacetal resin copolymer obtained as described above.

 3. Polyacetal resin (a) Strength The polyacetal resin composition according to claim 2, which is a polyacetal resin copolymer obtained by copolymerizing cyclic ether and Z or cyclic formal compound in a proportion of 0.5 to 20% by weight.

 4. Polyacetal resin (a) Strength The polyacetal resin composition according to claim 2, which is a polyacetal resin copolymer obtained by copolymerizing trioxane, which is a cyclic oligomer of formaldehyde, and 1,3-dioxolane, which is cyclic formal.

5. A molded article obtained by molding the polyacetal resin composition according to any one of claims 1 to 4, wherein the polyester resin (b) is dispersed in an equivalent circle diameter of 1. O ^ iii or less. Furthermore, at least one antioxidant selected from phenolic antioxidants, amine antioxidants, phosphorus antioxidants, thio antioxidants ij, hydroquinone antioxidants, quinoline antioxidants, The polyester resin composition according to claim 1, wherein 0.01 to 5 parts by weight of the polyester resin (a) is mixed with 100 parts by weight. The polyester resin composition according to claim 1, wherein the polyester resin composition satisfies the requirement (II) and the temperature difference between the melting point and the crystallization temperature of the polyester resin composition is 35 ° C or less.