JPH0329105B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel acetal polymer composition, and particularly to an acetal polymer composition having unprecedentedly excellent impact properties and a method for producing the same. Many attempts have been made to improve the impact properties of acetal polymers. For example, special public service in 1977-
In Japanese Patent Publication No. 18023, the addition of a so-called ionomer was added, and in Japanese Patent Publication No. 45-26231, the addition of an ethylene-acrylic acid copolymer was added.
-33095 proposes the addition of aliphatic polyether. The acetal polymer, which is a crystalline polymer, and the amorphous polymer proposed in these publications do not mix or dissolve easily, and it is extremely difficult to create a uniform composition of the two. . For this reason, the compositions proposed in these publications do not sufficiently improve impact properties, and the appearance of molded products is also poor. To improve non-uniform mixing and dissolution
Publication No. 19425 describes the reaction of a trioxane copolymer containing free amino groups with a polyether containing isocyanate groups. This method requires reducing the nitro groups in the trioxane copolymer to amino groups, and the polymer has the defect of violently decomposing during the reduction operation. Furthermore, JP-A-54-155248 proposes adding an elastomer and processing aids such as segmented polyester and polyurethane to polyoxymethylene. By adopting this method, although the impact value is improved, the appearance of the molded product is still poor. This is due to the fact that uniform mixing and dissolution of the elastomer and polyoxymethylene is insufficient even when segmented polyester and polyurethane are used as processing aids. Furthermore, the strength and rigidity of molded articles based on this composition are greatly reduced due to the addition of segmented polyester and polyurethane. The decrease in strength and rigidity will become clear in the comparative examples later. Acetal polymers are useful as engineering plastics due to their well-balanced physical properties. Attempts to improve impact properties even at the expense of strength and rigidity, such as the composition of the present invention, cannot necessarily be said to be an advantageous direction. As a result of extensive research into ways to improve the impact properties of acetal polymers, the present inventors found that
It has been discovered that a certain low molecular weight compound and a certain elastomer function as good molecular weight regulators. Furthermore, as a result, they discovered an acetal polymer composition that has outstanding impact properties not found in conventional acetal polymer compositions, and completed the present invention. Moreover, this composition maintains high strength and stiffness, and this composition can be appropriately called a highly balanced composition. That is, the present invention is composed of (A) 1.5 to 80% by weight of polyacetal, (B) a polyacetal portion, and an elastomer portion having a soft segment and a hard segment and having a secondary transition temperature of -120 to +40°C, The present invention relates to an acetal polymer composition having excellent impact properties and comprising two components of 98.5 to 20% by weight of an acetal copolymer having a number average molecular weight between 10,000 and 500,000. Furthermore, the present invention provides water having a number average molecular weight of 500 or less,
It has a low molecular weight compound selected from the group consisting of alcohol, carboxylic acid, carboxylic acid anhydride, amide, ester, and ether, and has a soft segment and a hard segment, and also has a hydroxyl group, a carboxyl group, a carboxylic acid anhydride group, and an amino group. formaldehyde in the coexistence of at least one thermoplastic elastomer having at least one functional group selected from the group consisting of , relates to a method for producing an acetal polymer composition with excellent impact properties, characterized by homopolymerizing trioxane or copolymerizing a cyclic ether with a compound selected from the group consisting of formaldehyde, trioxane and polyoxymethylene. be. The acetal polymer composition of the present invention has, for example, an Izot impact value (notched) of 8 to 100 Kg·cm/
cm, and has unprecedented impact properties. Demand for acetal polymers as engineering plastics has been increasing in recent years, and improving the impact properties of acetal polymers has great industrial significance. Next, the acetal polymer composition of the present invention will be explained in detail. In the present invention, the polyacetal of component A or the polyacetal segment of component B
contains a polyacetal homopolymer and a polyacetal copolymer. A polyacetal homopolymer is a polymer consisting of repeating oxymethylene units (-CH ₂ O)-, and is obtained by homopolymerizing formaldehyde and trioxane. Polyacetal copolymer has oxyalkylene units in the chain consisting of oxymethylene units. (R ₀ : selected from hydrogen, alkyl group, and phenyl group, each of which may be the same or different. m
= 2 to 6) are randomly inserted. The insertion rate of oxyalkylene units in the polyacetal copolymer is 0.05 to 50 mol, more preferably 0.1 to 20 mol, per 100 mol of oxymethylene units. Examples of oxyalkylene units include oxyethylene units, oxypropylene units, oxytrimethylene units, oxytetramethylene units, oxybutylene units, oxyphenylethylene units, and the like. Among these oxyalkylene units, from the viewpoint of improving the physical properties of the acetal polymer composition, oxyethylene units [-(CH ₂ ) ₂ O]- and oxytetramethylene units [-(CH ₂ ) ₄ O]- are used. Particularly preferred. Next, in the present invention, the acetal copolymer used as component B has a polyacetal portion (segment), a soft segment, and a hard segment, and has a second-order transition temperature (Tg,
It is a block copolymer or graft copolymer composed of a thermoplastic elastomer segment having a glass transition temperature) and having a number average molecular weight of between 10,000 and 500,000. Here, the block copolymer is A composed of a polyacetal part (A) and an elastomer part (B).
-B type diblock copolymer or A-B-A
It is a type of triblock copolymer. In addition, a graft copolymer is a polymer in which the elastomer portion is a trunk polymer and the polyacetal portion is a branch polymer. The elastomer part is a thermoplastic polymer, consisting of an amorphous segment with a low secondary transition temperature (soft segment) and a thermoreversible crosslinking and
It is a copolymer with segments (hard segments) that create a bonding structure. The number average molecular weight of the acetal copolymer is 10,000
It needs to be between ~500000. When the number average molecular weight is 10,000 or more, the impact properties of the composition are significantly improved, while when the number average molecular weight is 500,000 or less, it is easy to mix and melt uniformly with the other component, polyacetal. becomes. In the present invention, the elastomer portion that is a component of the acetal copolymer is selected from the group consisting of polyolefin elastomers, polystyrene elastomers, polyester elastomers, polyamide elastomers, and polyurethane elastomers. The first group of elastomers, polyolefin-based elastomers, include modified ethylene-propylene copolymers and modified ethylene-propylene-diene terpolymers. Here ethylene,
Dienes to be copolymerized with propylene as termonomers include dicyclopentadiene, ethylidene norbornene, methylene norbornene, 1,4
-Hexadiene, etc. Ethylene-propylene copolymers (EPM), ethylene-propylene-diene terpolymers (EPDM) are made of acrylic anhydride, acrylic acid, methacrylic acid, acrylic methyl acid in the presence or absence of peroxides. acid ester, methyl methacrylate, methacrylic acid 2
-Modified with unsaturated compounds such as methacrylic esters such as hydroxyethyl and allyl alcohol. In the present invention, ethylene-propylene copolymers and ethylene-propylene-diene terpolymers modified with unsaturated compounds are used. The second group of elastomer moieties are polystyrene-based elastomers, with polystyrene as the hard segment. Soft segments to be combined with polystyrene include diene systems such as polybutadiene and polyisoprene, and hydrogenated diene systems such as hydrogenated polybutadiene and hydrogenated polyisoprene. Among these polystyrene-based elastomers, polystyrene-
Polybutadiene block copolymers and hydrogenated polystyrene-polybutadiene block copolymers are preferred. In addition, modified polymers such as modified polystyrene-polybutadiene block copolymers can also be used in the present invention. The third group of elastomer parts are polyester elastomers, which have hard segments of polyester such as polyethylene terephthalate, polybutylene terephthalate, modified polyethylene terephthalate, and polyethylene-butylene terephthalate. Soft segments to be combined with polyesters include polyethers such as polypropylene glycol, polytetramethylene glycol, and the like. Among these polyester elastomers, polybutylene terephthalate-polytetramethylene glycol block copolymer and polyethylene-butylene terephthalate-polytetramethylene glycol block copolymer are particularly preferred. The fourth group of elastomer portions are polyamide-based elastomers, in which polyamides such as nylon 6, nylon 66, nylon 610, nylon 11, and nylon 12 are used as hard segments. Soft segments to be combined with polyamides include polyethers such as polypropylene glycol, polytetramethylene glycol, and polyesters such as polyethylene adipate and polybutylene succinate. Among these polyamide elastomers, nylon 6-polypropylene glycol block copolymer and nylon 6-polytetramethylene glycol block copolymer are particularly preferred. The fifth group of elastomer portions are polyurethane elastomers, with urethane as the hard segment. The urethane can be obtained by reacting a diisocyanate such as 4,4'-diphenylmethane diisocyanate or 4,4'-dicyclohexylmethane diisocyanate with a glycol such as ethylene glycol or tetramethylene glycol. Soft segments to be combined with urethane include polyester diols such as polyethylene adipate and polybutylene adipate, and polyether diols such as polypropylene glycol and polytetramethylene glycol. Among these polyurethane elastomers, polyurethanes synthesized from 4,4'-diphenylmethane diisocyanate, tetramethylene glycol and polytetramethylene glycol are particularly preferred. Specific examples of the acetal copolymer are shown below. (1) Diblock copolymer (A-B type) Polyacetal polystyrene-polybutadiene block copolymer, polyacetal polyethylene, butylene terephthalate-polytetramethylene glycol block copolymer,
Polyacetal/nylon 6-polypropylene glycol block copolymer (adipic acid linkage) (2) Triblock copolymer (A-B-A type) Polyacetal/hydrogenated polystyrene-polybutadiene block copolymer, polyacetal/polybutylene terephthalate-polytetramethylene glycol block Copolymer, polyacetal/nylon 6-polytetramethylene glycol block copolymer (succinic acid linkage), polyacetal/polyurethane (4,
(3) Graft copolymer Polyacetal/maleic anhydride modified ethylene-propylene copolymer (maleic anhydride modified ethylene-propylene copolymer) Polymer with copolymer as the trunk polymer and polyacetal as the branch polymer), polyacetal/methacrylic acid 2-
Hydroxyethyl (HEMA) modified ethylene-
Propylene-ethylidene norbornene terpolymer (abbreviated as HEMA-EPDM, HEMA-
Polymers having EPDM as a trunk polymer and polyacetal as a branch polymer) Here, the elastomer content of these acetal copolymers must be in the range of 1.0 to 60% by weight. If the content of the elastomer portion is too low, no improvement in the impact properties of the composition will be observed, while if it is too high, the strength and rigidity of the composition will be reduced. In the composition of the present invention, the composition ratio of the polyacetal as component (A) is in the range of 1.5 to 80% by weight,
In addition, the composition ratio of the acetal copolymer of component (B) is 98.5
It is necessary that the content be in the range of ~20% by weight. When the composition ratio of the acetal copolymer is 20% by weight or more, the impact properties of the acetal polymer composition are significantly improved. On the other hand, the composition ratio of acetal copolymer
It is extremely easy to produce an acetal polymer composition of 98.5% by weight or less in terms of polymerization technology. Therefore, based on these two constraints, the composition ratio of the acetal copolymer is set between 98.5 and 20% by weight. In order to further improve the impact properties and fatigue resistance of the acetal polymer composition, the composition ratio of the polyacetal as component (A) is in the range of 3.0 to 70% by weight,
The composition ratio of the acetal copolymer of component (B) is 97.0~
More preferably, the content is in the range of 30% by weight. The composition ratio of the two types of polymers constituting the composition of the present invention can be easily determined by terminal analysis of the composition and elastomer partial content analysis mainly based on hydrolyzing the polymer. . Next, a method for producing the acetal polymer composition of the present invention will be described. The acetal polymer composition of the present invention has a number average molecular weight of 500 or less, including water, alcohol, carboxylic acid,
A low molecular weight compound selected from the group consisting of carboxylic acid anhydride, amide, ester and ether, and a soft segment and a hard segment, and selected from the group consisting of hydroxyl group, carboxyl group, carboxylic acid anhydride group and amino group. The polymer has at least one functional group with a secondary transition temperature of -120
Homopolymerization of formaldehyde trioxane or cyclic ether with a compound selected from the group consisting of formaldehyde, trioxane and polyoxymethylene in the coexistence of at least one thermoplastic elastomer between ~+40°C. Obtained by copolymerization. In the present invention, a low molecular compound and an elastomer are used together as a molecular weight regulator. The elastomer functions as a molecular weight regulator during polymerization, adjusting the molecular weight of the polymer, and at the same time is inserted into the polymer as a blocking macromer. The low-molecular compound that can be used in the present invention has a number average molecular weight of 500 or less, and is selected from the group consisting of water, alcohol, carboxylic acid, carboxylic acid anhydride, amide, ester, and ether. Here, the alcohol includes aliphatic alcohols such as methanol, ethanol, octanol, lauryl alcohol and stearyl alcohol, and aromatic alcohols such as benzyl alcohol. Carboxylic acids include formic acid, acetic acid, propionic acid,
These include aliphatic carboxylic acids such as lauric acid and stearic acid, and aromatic carboxylic acids such as benzoic acid and m-nitrobenzoic acid. Examples of carboxylic anhydrides include aliphatic carboxylic anhydrides such as acetic anhydride, propionic anhydride, and caproic anhydride, and aromatic carboxylic anhydrides such as benzoic anhydride. Amides include aliphatic amides such as formamide, dimethylformamide, acetamide, and propionamide, and aromatic amides such as benzamide. Esters include aliphatic esters such as methyl formate, methyl acetate, butyl caproate, and methyl laurate, and aromatic esters such as methyl benzoate and ethyl benzoate. Ether contains methylal,
These include formal compounds such as acetal, diethoxymethane, and dipropoxymethane. These low molecular weight compounds may be used alone or in combination of two or more. Next, the elastomer that can be used in the present invention has at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, a carboxylic anhydride group, and an amino group, and has a molecular weight of -120 to +40.
It is a thermoplastic polymer consisting of soft segments and hard segments and has a second-order transition temperature (Tg, glass transition temperature) of °C. When an elastomer having one functional group is used as a molecular weight modifier, an AB type diblock copolymer is produced. When an elastomer having two functional groups is used, an ABA type triblock copolymer is produced. Further, when an elastomer having three or more functional groups is used, a graft copolymer is produced in which the elastomer portion is the trunk polymer and the polyacetal portion is the branch polymer. Elastomers that can be used in the present invention can be classified into the following five groups. The first group of elastomers are polyolefin elastomers, such as maleic anhydride-modified ethylene-propylene copolymers (containing 5 carboxylic anhydride groups) and 2-hydroxyethyl methacrylate-modified ethylene-propylene copolymers (containing 10 hydroxyl groups). , allyl alcohol-modified ethylene-propylene-ethylidene norbornene terpolymer (containing 15 hydroxyl groups), and the like. The second group of elastomers are polystyrene-based elastomers, such as polystyrene-polybutadiene block copolymers (containing 2 hydroxyl groups), maleic anhydride-modified hydrogenated polystyrene-polybutadiene block copolymers (containing 6 carboxylic anhydride groups), and hydrogenated polystyrene. -Polyisoprene block copolymers (containing two hydroxyl groups), etc. The third group of elastomers are polyester elastomers, including polybutylene terephthalate-polytetramethylene glycol block copolymer (containing one hydroxyl group and one carboxyl group), polyethylene-butylene terephthalate-
Examples include polytetramethylene glycol block copolymers (containing two hydroxyl groups). The fourth group of elastomers are polyamide elastomers, such as nylon 6-polypropylene glycol block copolymer (containing one hydroxyl group and one amino group), nylon 6-polytetramethylene glycol block copolymer (containing two hydroxyl groups), etc. be. The fifth group of elastomers are polyurethane elastomers, such as polyurethanes synthesized from 4,4'-diphenylmethane diisocyanate, tetramethylene glycol, and polytetramethylene glycol. These elastomers may be used alone or in a mixture of two or more. In the polymerization of the present invention, sufficiently purified formaldehyde, trioxane, polyoxymethylene and cyclic ether are used as starting materials for polyacetals and acetal copolymers. Here, polyoxymethylene is generally a homopolymer of formaldehyde or trioxane, and has, for example, a number average molecular weight of 10,000 to 500,000, preferably 30,000 to 150,000. The first group of cyclic ethers has the general formula (R ₀ ; selected from hydrogen, alkyl group, and phenyl group, each of which may be the same or different. m
There are alkylene oxides represented by =2 to 6). For example, ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin,
Examples include styrene oxide, oxetane, 3,3-bis(chloromethyl)oxetane, tetrahydrofuran, oxepane, and the like. Among these alkylene oxides, ethylene oxide is particularly preferred. The second group of cyclic ethers has the general formula There is a cyclic formal represented by For example, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4
-butanediol formal, 1,5-pentanediol formal, and 1,6-hexanediol formal. Among these cyclic formals, ethylene glycol formal, diethylene glycol formal and 1,4-butanediol formal are particularly preferred. Cyclic ether per 100 parts by weight of starting materials
0.03 to 100 parts by weight, more preferably 0.1 to 50 parts by weight are used. Anionic polymerization catalyst used in the polymerization of the present invention,
Cationic polymerization catalysts are the following compounds. Typical groups of anionic polymerization catalysts include alkali metals such as sodium and potassium, alkali metal complexes such as sodium-naphthalene and potassium-anthracene, alkali metal hydrides such as sodium hydride, and alkaline earths such as calcium hydride. metal hydrides, alkali metal alkoxides such as sodium methoxide and potassium t-butoxide, alkali metal carboxylates such as sodium caproate and potassium stearate, alkaline earth metal carboxylates such as magnesium caproate and calcium stearate, Amines such as n-butylamine, diethylamine, trioctylamine, pyridine, ammonium stearate,
Quaternary ammonium salts such as tetrabutylammonium methoxide and dimethyldistearylammonium acetate; phosphonium salts such as tetramethylphosphonium propionate and trimethylbenzylphosphonium ethoxide; quaternary ammonium salts such as tributyltin chloride, diethyltin dilaurate, and dibutyltin dimethoxide Examples include valent organic tin compounds, alkyl metals such as n-butyllithium, and ethylmagnesium chloride. Cationic polymerization catalysts include tin tetrachloride, tin tetrabromide, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony pentafluoride, boron trifluoride, boron trifluoride diethyl etherate,
So-called Friedel-Crafts type compounds such as boron trifluoride coordination compounds such as boron trifluoride acetic anhydrate and boron trifluoride triethylamine complex compounds, perchloric acid, acetyl perchlorate, hydroxyacetic acid, trichloroacetic acid, Inorganic and organic acids such as p-toluenesulfonic acid, complex salt compounds such as triethyloxonium tetrafluoroborate, triphenylmethylhexafluoroantimonate, allyldiazonium hexafluorophosphate, allyldiazonium tetrafluoroborate, diethylzinc, triethyl aluminum,
Examples include alkyl metals such as diethylaluminium chloride. These anionic polymerization catalysts and cationic polymerization catalysts are used in an amount of 0.0005 to 5 parts by weight based on 100 parts by weight of the starting material. Polymerization is carried out without a solvent or in an organic medium. Organic media that can be used in the present invention include aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, and cyclopentane, benzene, toluene,
Examples include aromatic hydrocarbons such as xylene, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, ethylene chloride, and trichloroethylene, and halogenated aromatic hydrocarbons such as chlorobenzene and o-dichlorobenzene. These organic media may be used alone or in combination of two or more. The low molecular weight compound and elastomer which are molecular weight modifiers are used after being uniformly dissolved or dispersed in the reaction system. The polymerization temperature is usually set between -20 and 230°C, but preferably between 20 and 210°C in the case of no solvent, and -10 to 120°C in the case of using an organic medium.
It is more preferable. There are no particular restrictions on polymerization time, but from 5 seconds to
Set between 300 minutes. After a predetermined period of time has elapsed, a terminator is added to the reaction system to complete the polymerization. The obtained polymer is stabilized by removing unstable ends by hydrolysis or blocking unstable ends by a method such as esterification. It is also possible to further add a conventionally known compound as a stabilizer for polyacetal to the composition of the present invention comprising a stabilized polyacetal and an acetal copolymer. The first known stabilizer
is a heat stabilizer and is used for amide compounds, polyamides,
Examples include amidine compounds, melamine, polyvinylpyrrolidone, carboxylic acid metal salts, etc. A second type of known stabilizer is an antioxidant, such as a hindered phenol compound. Further, the third known stabilizer is a light stabilizer,
Examples include benzotriazole compounds and hydroxybenzophenone compounds. These stabilizers are usually added in an amount of 0.05 to 10 parts by weight, more preferably 0.08 to 3 parts by weight, per 100 parts by weight of the acetal polymer composition. The features of the acetal polymer composition of the present invention and its production method which have been described in detail above are listed below. (1) The acetal polymer composition has extremely excellent impact properties, and at the same time has good strength and rigidity. (2) Excellent performance can be imparted to acetal polymer compositions by using specific elastomers. (3) The molecular weight of polyacetals and acetal copolymers can be controlled arbitrarily by using a specific low-molecular compound and a specific elastomer as molecular weight regulators. Hereinafter, the present invention will be specifically explained with reference to Examples. The measurement items in the examples are as follows. MI: 2,2-methylene-bis(4-
methyl-6-tert-butylphenol) 0.25 parts,
0.50 parts of nylon 66 was added and pelletized using a 50 mmφ extruder. The MI of this pellet is
Measured according to ASTM-D 1238-57T. MI is a measure of molecular weight. Izot impact value (notched): The above pellet was molded into a flat plate using an injection molding machine. A test piece was cut from this flat plate and measured according to ASTM-D256. The larger the Izot impact value, the better the impact properties. Vibration fatigue characteristics: Cut a test piece from a flat plate,
Measured at 20°C and repeated vibration cycles of 1800 times/min in accordance with ASTM-D671. 10 Maximum stress that does not cause the test piece to break when subjected to repeated vibrations ⁶ times =
Fatigue strength is used as an index of fatigue resistance. The higher the fatigue strength, the better the fatigue resistance. Tensile strength: Cut a test piece from a flat plate, ASTM-
Measured according to D638. The higher the tensile strength, the better the strength and rigidity. Example 1 (1) Manufacturing method of acetal polymer composition Formaldehyde gas with a purity of 99.9% was mixed at a rate of 100 parts per hour (hereinafter, parts indicate parts by weight), and 0.065 gr/methanol and 0.065 gr/methanol as a molecular weight regulator. 50.0gr/polybutylene terephthalate-polytetramethylene glycol block copolymer (hereinafter abbreviated as PBT-PTG),
As a polymerization catalyst, 500 parts of toluene containing 3.0×10 ⁻⁴ mol/dimethyl distearyl ammonium acetate was continuously supplied for 3 hours. PBT- used here as a molecular weight regulator
PTG is an elastomer having a number average molecular weight of 2.1×10 ⁴ and two hydroxyl group terminals, synthesized from the following raw materials. Dimethyltetramethylene glycol terephthalate polytetramethylene glycol (n 1250) Toluene containing methanol, PBT-PTG, and polymerization catalyst at the above concentrations was also continuously supplied at a rate of 500 parts/hr for 3 hours, and the polymerization temperature was maintained at a constant temperature during this period.
It was maintained at 62°C. The polymer was separated from toluene, then washed and dried to obtain 432 parts of polymer. After acetylating this polymer, it was extracted in benzyl alcohol at 160°C for 5 hours, but unreacted PBT-PTG was not extracted at all. From this, it became clear that all PBT-PTG was inserted into the polymer. (2) Confirmation of composition After acetylating the polymer obtained in (1), the terminal groups of the polymer were analyzed and quantified using infrared absorption spectroscopy and Zeisel method. As a result, it became clear that the polymer obtained in (1) was composed of the following two types of polymers. Polymer 1 (polyacetal) CH ₃ O (-CH ₂ O) - ₁₃₀₀ H 36% by weight Polymer 2 (acetal copolymer) HO (-CH ₂ O) - _1300-c X ₁ (-CH ₂ O) - _c H 64% by weight (Here, X ₁ is PBT-PTG, which is composed of the following soft segments and hard segments. Moreover, c represents 1 to 1299. ) Among the above two types of polymers, Polymer 1 is a polymer based on methanol added as a molecular weight regulator, and Polymer 2 is a polymer based on an elastomer (PBT-PTG) added as a molecular weight regulator. . Further, the content of the elastomer portion in the acetal copolymer of Polymer 2 is 35% by weight. (3) Measurement of physical properties of acetal polymer composition When a stabilizer was added to a polymer that had been terminally stabilized using acetic anhydride and molded, a very tough molded product could be obtained. The physical properties of this molded article are as follows. MI 12.6 (gr/10 min) Izot impact value 38.5 (Kg cm/cm) Fatigue strength 275 (Kg/cm ² ) Tensile strength 610 (Kg/cm ² ) Thus, this composition has the desired molecular weight. ,
It has excellent impact properties. Example 2 (4) Preparation of acetal polymer composition Formaldehyde at a ratio of 100 parts/hr, ethylene oxide at a ratio of 2.2 parts/hr, 0.014 gr/hr of water and 36.6 gr/hr of nylon 6-polypropylene glycol block as molecular weight modifiers. The mixture was continuously fed into 500 parts of toluene containing a copolymer (hereinafter abbreviated as NY-PPG) for 5 hours. The elastomer used here as a molecular weight regulator was synthesized from the following raw materials, and is a polymer having a number average molecular weight of 8.5×10 ³ and a carboxyl group terminal, with the amino group end blocked with acetic acid. Prepolymer made by reacting polypropylene glycol and adipic acid (n1550) ε-caprolactam polymer (nylon 6,
n1170) Water and toluene containing NY-PPG at the above concentrations were also continuously supplied at a rate of 500 parts/hr for 5 hours. Additionally, as polymerization catalysts, tetrabutylammonium acetate and boron trifluoride dibutyl etherate were continuously supplied through separate conduits at a rate of 0.03 parts/hr and 0.08 parts/hr, respectively, for 5 hours, and the polymerization temperature was maintained at 60°C during this time. did. The polymer was separated from toluene, then washed and dried to obtain 596 parts of polymer. After acetylating this polymer, it was extracted in benzyl alcohol at 160°C for 5 hours.
No unreacted NY-PPG was extracted. (5) Confirmation of composition After acetylating the polymer obtained in (4), ethylene oxide insertion rate analysis, terminal group analysis, and elastomer portion content analysis were conducted. As a result, it became clear that the polymer obtained in (4) was composed of the following two types of polymers. Polymer 3 (polyacetal) HO {(-CH ₂ O)- ₁₃₀₀ (-CH ₂ CH ₂ O)- ₂₀ }-H
15% by weight Polymer 4 (acetal copolymer) X ₂ {(-CH ₂ O)- ₁₃₀₀ (-CH ₂ CH ₂ O)- ₂₀ }-H
85% by weight (where {(-CH ₂ O)- ₁₃₀₀ (-CH ₂ CH ₂ O)- ₂₀ }- is
It shows that 20 oxyethylene groups are randomly inserted into 1300 oxymethylene chains. Also, X ₂ is NY-PPG, which is composed of the following soft segment and hard segment. Of the two types of polymers mentioned above, Polymer 3 is a polymer based on water added as a molecular weight regulator, and Polymer 4 is a polymer based on an elastomer (NY-PPG) added as a molecular weight regulator. Further, the content of the elastomer portion in the acetal copolymer of Polymer 4 is 18% by weight. (6) Measurement of physical properties of acetal polymer composition The composition obtained in (4) has the following physical property values. MI 14.6 (gr/10 min) Izot impact value 23.2 (Kg/cm/cm) Fatigue strength 265 (Kg/cm ² ) Tensile strength 575 (Kg/cm ² ) This composition also has the desired molecular weight and impact properties. Excellent. Example 3 (7) Manufacturing method of acetal polymer composition 5.02 kg of polyoxymethylene sufficiently dried under reduced pressure, ethylene glycol formal
420gr, acetic acid 2.1gr as a molecular weight regulator, maleic anhydride modified hydrogenated polystyrene-polybutadiene block copolymer (MPS-PBG)
(abbreviated as) 3.25Kg and 50Kg of cyclohexane were charged into the reaction tank. Here, it was used as a molecular weight regulator.
MPS-PBG is a polystyrene-polybutadiene block copolymer synthesized by a living polymerization method, which is hydrogenated and then modified with maleic anhydride in an extruder, and has three carboxylic anhydride groups in the polymer. It is something. After charging, the contents of the reaction tank were heated to 70°C. The reaction was started by adding 1.25g of boron trifluoride dibutyl etherate to the reaction tank. After maintaining the internal temperature of the reaction vessel at 70° C. for 30 minutes, 570 gr of cyclohexane containing 150 gr of tributylamine was added to stop the reaction. After the polymer was filtered off, it was washed five times with a large amount of toluene, and 8.18 kg of polymer was recovered. (8) Confirmation of composition The end group analysis of the polymer revealed that the polymer obtained in (7) was composed of the following two types of polymers. Polymer 5 (polyacetal) Polymer 6 (acetal copolymer) Maleic anhydride modified hydrogenated polystyrene
75% by weight graft copolymer with polybutadiene block copolymer as the backbone polymer and {(-CH ₂ O)- ₈₁₀ (-CH ₂ CH ₂ O)- ₂₆ }-H as the branch polymer.
(Here, {(-CH ₂ O)- ₈₁₀ (-CH ₂ CH ₂ O)- ₂₆ }- is
It shows that 26 oxyethylene groups are randomly inserted into 810 oxymethylene chains. ) Among the above two types of polymers, Polymer 5 is a polymer based on acetic acid added as a molecular weight regulator, and Polymer 6 is a polymer based on an elastomer (MPS-PBD) added as a molecular weight regulator. . Further, the content of the elastomer portion in the acetal copolymer of Polymer 6 is 46% by weight. (9) Measurement of physical properties of acetal polymer composition As shown below, the composition obtained in (8) has a desired molecular weight and excellent impact properties. MI 2.8 (g/10 minutes) Izot impact value 31.5 (Kg cm/cm) Fatigue strength 263 (Kg/cm ² ) Tensile strength 570 (Kg/cm ² ) Examples 4 to 35 Starting materials shown in Table 1 and Using a molecular weight regulator (low molecular weight compound, elastomer), acetal polymer compositions shown in Table 1 were obtained. The physical properties of the acetal polymer composition are also shown in Table 1. In all Examples, compositions with desired molecular weights and excellent impact properties were obtained.

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[Table] Comparative Examples 1 to 6 Polyacetals having the physical properties shown in Table 2 were obtained using the starting materials shown in Table 2 and simple polymers. In all comparative examples, the impact properties of the resulting polyacetals were poor.

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Claims (1)

[Claims] 1. (A) 1.5 to 80% by weight of polyacetal (B) A polyacetal portion, a thermoplastic elastomer portion having a soft segment and a hard segment, and having a secondary transition temperature of -120 to +40°C. The number average molecular weight is 10,000 to 500,000.
An acetal polymer composition comprising 98.5 to 20% by weight of an acetal copolymer between 2 The polyacetal of component (A) or the polyacetal part of component B has an oxymethylene unit (-
The composition according to claim 1, which is a polyacetal homopolymer consisting of repeating _CH2O )-. 3. An oxyalkylene unit in a polymer in which the polyacetal of component A or the polyacetal part of component B consists of repeating oxymethylene units. (R ₀ ; selected from hydrogen, alkyl group, and phenyl group, each of which may be the same or different. m
2. The composition according to claim 1, which is a polyacetal copolymer having a structure in which 2 to 6) are randomly inserted. 4. The composition according to claim 1 or 3, wherein the oxyalkylene unit is an oxyethylene unit [-(CH ₂ ) ₂ O]-. 5. The composition according to claim 1 or 3, wherein the oxyalkylene unit is an oxytetramethylene unit [-( _CH2 ) _4O ]-. 6. The composition according to claim 1, wherein the elastomer portion of component B is an elastomer selected from the group consisting of polyolefin elastomers, polystyrene elastomers, polyester elastomers, polyamide elastomers, and polyurethane elastomers. 7. The composition according to claim 1 or 6, wherein the polyolefin elastomer is a modified ethylene-propylene copolymer or a modified ethylene-propylene-diene terpolymer. 8. The composition according to claim 1 or 6, wherein the polystyrene elastomer is an elastomer selected from the group consisting of polystyrene-polybutadiene block copolymer, hydrogenated polystyrene-polybutadiene block copolymer, and modified polystyrene-polybutadiene block copolymer. . 9. The composition according to claim 1 or 6, wherein the polyester elastomer is a polybutylene terephthalate-polytetramethylene glycol block copolymer or a polyethylene-butylene terephthalate-polytetramethylene glycol block copolymer. 10 Polyamide elastomer is nylon-
7. The composition according to claim 1 or 6, which is a 6-polypropylene glycol block copolymer or a nylon-6-polytetramethylene glycol block copolymer. 11 Polyurethane elastomer is 4,4′-
7. The composition according to claim 1 or 6, which is a polyurethane synthesized from diphenylmethane diisocyanate, tetramethylene glycol, and polytetramethylene glycol. 12. The composition according to claim 1, wherein the elastomer content of the acetal copolymer of component B is in the range of 1.6 to 60% by weight. 13 Water, alcohol, with a number average molecular weight of 500 or less,
It has at least one low molecular weight compound selected from the group consisting of carboxylic acid, carboxylic acid anhydride, amide, ester and ether, a soft segment and a hard segment, and has a hydroxyl group, a carboxyl group, a carboxylic acid anhydride group and In coexistence with at least one thermoplastic elastomer having at least one functional group selected from the group consisting of amino groups and having a secondary transition temperature between -120 and +40°C,
A method for producing an acetal polymer composition comprising a polyacetal and an acetal copolymer, characterized by homopolymerizing formaldehyde or trioxane. 14 Water, alcohol, with a number average molecular weight of 500 or less,
It has a low molecular compound selected from the group consisting of carboxylic acid, carboxylic acid anhydride, amide, ester, and ether, and has a soft segment and a hard segment, and is composed of a hydroxyl group, a carboxyl group, a carboxylic acid anhydride group, and an amino group. Formaldehyde, trioxane and A method for producing an acetal polymer composition comprising a polyacetal and an acetal copolymer, characterized by copolymerizing a compound selected from the group consisting of polyoxymethylene and a cyclic ether. 15. The production method according to claim 14, wherein the cyclic ether is ethylene oxide. 16 Cyclic ether is ethylene glycol formal, diethylene glycol formal and 1,
15. The method according to claim 14, wherein the compound is selected from the group consisting of 4-butanediol formal.