JP5673991B2 - Dispersibility improver, thermoplastic resin composition, and molded article - Google Patents

Description

  The present invention relates to a dispersibility improver for a polytetrafluoroethylene-containing modifier, the dispersibility improver, a thermoplastic resin composition containing the polytetrafluoroethylene-containing modifier and a thermoplastic resin, and the thermoplastic resin composition. The present invention relates to a molded body obtained by molding a product.

  Polytetrafluoroethylene has high crystallinity and low intermolecular force, so it has the property of fiberizing with a slight stress. When blended into a thermoplastic resin and kneaded, it can be used for fiberizing polytetrafluoroethylene. Along with this, it is known that molding processability and mechanical properties are improved.

For example, Patent Document 1 proposes a thermoplastic resin composition in which polytetrafluoroethylene is blended with a thermoplastic resin. However, since polytetrafluoroethylene is blended directly into the thermoplastic resin, the dispersibility of polytetrafluoroethylene is low and the appearance of the molded article is poor.
In order to solve the above problem, Patent Document 2 proposes a thermoplastic resin composition in which acrylic-modified polytetrafluoroethylene is blended with a thermoplastic resin. Although the appearance of the molded body was improved as compared with the case where unmodified polytetrafluoroethylene was used, it was insufficient to meet the demand for more sophisticated molded appearance.

JP-A-6-306212 Japanese Patent Laid-Open No. 11-124478

  The object of the present invention is to improve the dispersibility of the polytetrafluoroethylene component in the molded body while maintaining the molding processability of the thermoplastic resin composition, which is the original performance of the polytetrafluoroethylene-containing modifier, Another object of the present invention is to provide a dispersibility improver for a polytetrafluoroethylene-containing modifier that gives the appearance of a molded article.

  The present invention is a dispersibility improver for a polytetrafluoroethylene-containing modifier containing an alkyl methacrylate polymer (A) whose main component is an alkyl methacrylate (a1) unit having an alkyl group having 2 or more carbon atoms. .

Moreover, this invention is a thermoplastic resin composition containing the said dispersibility improvement agent, a polytetrafluoroethylene containing modifier, and a thermoplastic resin.
Moreover, this invention is a manufacturing method of the thermoplastic resin composition which mix | blends the said dispersibility improvement agent, a polytetrafluoroethylene containing modifier, and a thermoplastic resin.
Furthermore, this invention is a molded object obtained by shape | molding the said thermoplastic resin composition.

  By using the dispersibility improver of the polytetrafluoroethylene-containing modifier of the present invention, molding is performed while maintaining the moldability of the thermoplastic resin composition, which is the original performance of the polytetrafluoroethylene-containing modifier. The dispersibility of the polytetrafluoroethylene component in the body is increased, and an excellent appearance of the molded body is given.

The alkyl methacrylate polymer (A) of the present invention contains an alkyl methacrylate (a1) unit having an alkyl group having 2 or more carbon atoms as a main component.
In the alkyl methacrylate polymer (A), the content of the alkyl methacrylate (a1) unit having an alkyl group having 2 or more carbon atoms in 100% by mass of all monomer units is 50% by mass or more, and 70% by mass. The above is preferable, and it is more preferably 85% by mass or more.
When the content of the alkyl methacrylate (a1) unit having an alkyl group having 2 or more carbon atoms is 50% by mass or more, the dispersibility of polytetrafluoroethylene in the thermoplastic resin is excellent.

  The alkyl methacrylate polymer (A) of the present invention can be obtained by polymerizing the monomer component (a) whose main component is an alkyl methacrylate (a1) having an alkyl group having 2 or more carbon atoms.

Examples of the alkyl methacrylate (a1) having an alkyl group having 2 or more carbon atoms include ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, sec-butyl methacrylate, t- Examples include butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, and stearyl methacrylate. These alkyl methacrylates (a1) having an alkyl group having 2 or more carbon atoms may be used alone or in combination of two or more.
Among these alkyl methacrylates (a1) having an alkyl group having 2 or more carbon atoms, the dispersibility improver is excellent in powder handling properties and dispersibility of polytetrafluoroethylene in a thermoplastic resin. Alkyl methacrylate having 2 to 6 alkyl groups is preferable, alkyl methacrylate having 4 carbon atoms is more preferable, and i-butyl methacrylate is more preferable.

The monomer component (a) may contain other monomer (a2) that can be copolymerized in addition to the alkyl methacrylate (a1) having 2 or more carbon atoms, if necessary. Examples of these other monomers (a2) include methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, sec-butyl acrylate, and t-butyl acrylate. , N-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, stearyl acrylate and other acrylates; methyl methacrylate; styrene, α-methyl styrene, chlorostyrene and other aromatic vinyl monomers; (Meth) acrylic acid; vinyl cyanide monomers such as (meth) acrylonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; vinyl acetate, vinyl butyrate, etc. Carboxylic acid vinyl monomers, ethylene, propylene, and olefin monomers of butylene and the like. These other monomers (a2) may be used alone or in combination of two or more.
Among these other monomers (a2), the copolymer has good copolymerizability with an alkyl methacrylate (a1) having 2 or more carbon atoms and suppresses the thermal decomposition of the alkyl methacrylate polymer (A). Is preferred. When the monomer component (a) contains an acrylate, the acrylate content is preferably 0.1 to 15% by mass in 100% by mass of the monomer component (a).

As a composition ratio of the monomer component (a), the carbon number is 2 or more in a total of 100% by mass of the alkyl methacrylate (a1) having an alkyl group having 2 or more carbon atoms and the other monomer (a2). The alkyl methacrylate (a1) having an alkyl group is preferably 50% by mass or more and the other monomer (a2) is preferably 50% by mass or less, and the alkyl methacrylate (a1) having an alkyl group having 2 or more carbon atoms is preferably used. More preferably, 70% by mass or more, and other monomer (a2) is 30% by mass or less, and alkyl methacrylate (a1) having an alkyl group having 2 or more carbon atoms is 85% by mass or more, and other single amount. The body (a2) is more preferably 15% by mass or less.
When the alkyl methacrylate (a1) having an alkyl group having 2 or more carbon atoms is 50% by mass or more, the dispersibility of polytetrafluoroethylene in the thermoplastic resin is excellent.
When the other monomer (a2) is 50% by mass or less, the dispersibility of polytetrafluoroethylene in the thermoplastic resin is excellent.

Examples of the polymerization method of the alkyl methacrylate polymer (A) of the present invention include known polymerization methods such as emulsion polymerization, soap-free emulsion polymerization, fine suspension polymerization, suspension polymerization, bulk polymerization, and solution polymerization. .
Among these polymerization methods, emulsion polymerization and soap-free emulsion polymerization are preferable because emulsion compounding and soap-free emulsion polymerization are more preferable because the dispersibility improver and the polytetrafluoroethylene-containing modifier are easy to mix. preferable.

  The particle structure in the case of polymerizing the alkyl methacrylate polymer (A) of the present invention using a polymerization method capable of obtaining a particle structure such as emulsion polymerization and soap-free emulsion polymerization may be a single layer structure. A multilayer structure may be used. When the particle structure is a multilayer structure particle, the structure is preferably a three-layer structure or less from the viewpoint of reducing the production cost.

  As the emulsifier when the alkyl methacrylate polymer (A) of the present invention is obtained by emulsion polymerization, known emulsifiers can be used, for example, anionic emulsifier, nonionic emulsifier, polymer emulsifier, radical polymerization in the molecule. Reactive emulsifiers with possible unsaturated double bonds are mentioned.

Examples of the anionic emulsifier include “New Coal 560 SF”, “Same 562 SF”, “Same 707 SF”, “Same 707 SN”, “Same 714 SF”, “Same 723 SF”, “Same 740 SF”, “Same 2308 SF”, “ 2320SN ”,“ 1305SN ”,“ 271A ”,“ 271NH ”,“ 210 ”,“ 220 ”,“ RA331 ”,“ RA332 ”(trade name, manufactured by Nippon Emulsifier Co., Ltd.), “Latemul B-118E”, “Lebenol WZ”, “Neopelex G15” (trade name, manufactured by Kao Corporation), “Haitenol N08” (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).
Examples of the nonionic emulsifier include “Nonipol 200” and “New Pole PE-68” (trade names, manufactured by Sanyo Chemical Industries, Ltd.).
Examples of the polymer emulsifier include polyvinyl alcohol, polyhydroxyethyl (meth) acrylate, polyhydroxypropyl (meth) acrylate, and polyvinylpyrrolidone.
Examples of reactive emulsifiers include “Antox MS-60”, “Same MS-2N” (trade name, manufactured by Nippon Emulsifier Co., Ltd.), and “Eleminol JS-2” (trade name, manufactured by Sanyo Chemical Industries, Ltd.). ), “Latemul S-120”, “S-180”, “S-180A”, “PD-104” (manufactured by Kao Corporation), “Adekalia Soap SR-10”, “SE- 10 "(trade name, manufactured by ADEKA Corporation)," Aqualon KH-05 "," Same KH-10 "," Same HS-10 "(trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Anionic emulsifiers; “Adekaria soap NE-10”, “same ER-10”, “same NE-20”, “same ER-20”, “same NE-30”, “same ER-30”, “same NE” -40 "," same ER-40 "(trade name, manufactured by ADEKA Corporation)," AQUALON RN-1 Reactive nonionic emulsifiers such as “0”, “RN-20”, “RN-30”, “RN-50” (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).
These emulsifiers may be used individually by 1 type, and may use 2 or more types together.

  A known radical polymerization initiator can be used as the polymerization initiator for obtaining the alkyl methacrylate polymer (A) of the present invention.

Examples of the radical polymerization initiator include persulfate compounds such as potassium persulfate, sodium persulfate, and ammonium persulfate; azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2 , 2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile Oil-soluble azo compounds such as 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, 2,2′-azobis {2- Methyl-N- [2- (1-hydroxyethyl)] propionamide}, 2,2′-azobis {2-methyl-N- [2- (1-hydroxybutyl)] propion Mido}, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] and its salts, 2,2′-azobis [2- (2-imidazolin-2-yl) propane And its salts, 2,2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] and its salts, 2,2′-azobis {2- [1- (2 -Hydroxyethyl) -2-imidazolin-2-yl] propane} and salts thereof, 2,2′-azobis (2-methylpropionamidine) and salts thereof, 2,2′-azobis (2-methylpropyneamidine) And its salts, water-soluble azo compounds such as 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] and its salts; benzoyl peroxide, cumene hydroperoxide, t- Chill hydroperoxide, t- butyl peroxy-2-ethylhexanoate, an organic peroxide such as t-butyl peroxy isobutyrate and the like.
These radical polymerization initiators may be used alone or in combination of two or more. Moreover, when superposing | polymerizing by an emulsion polymerization method, reducing agents, such as sodium bisulfite, ferrous sulfate, ascorbate, can also be used in combination with the said radical polymerization initiator.

The method for recovering the alkyl methacrylate polymer (A) of the present invention is not particularly limited, and can be appropriately selected depending on the polymerization method. For example, as a method for recovering the latex of the alkyl methacrylate polymer (A) when the alkyl methacrylate polymer (A) is obtained by emulsion polymerization, for example, a coagulation method, spray drying method, centrifugal separation method, freeze drying method Is mentioned.
Among these recovery methods, a coagulation method and a spray drying method are preferable from the viewpoint of uniformity of the obtained alkyl methacrylate polymer (A) powder.

  When the powder of the alkyl methacrylate polymer (A) is recovered using the coagulation method, the latex of the alkyl methacrylate polymer (A) is brought into contact with the coagulant at 30 to 90 ° C. and coagulated while stirring. The slurry is made into a slurry and dehydrated and dried to recover the alkyl methacrylate polymer (A) powder. Examples of the coagulant used in the coagulation method include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid; organic acids such as formic acid and acetic acid; inorganic salts such as aluminum sulfate, magnesium sulfate and calcium sulfate; organics such as calcium acetate Examples include salts.

When powder recovery of the alkyl methacrylate polymer (A) is performed using a spray drying method, the latex of the alkyl methacrylate polymer (A) is subjected to conditions of an inlet temperature of 120 to 220 ° C and an outlet temperature of 40 to 90 ° C. The powder of the alkyl methacrylate polymer (A) can be recovered by spray drying with a spray dryer.
The outlet temperature in the spray drying method is preferably 40 to 80 ° C., and preferably 40 to 70 ° C., because the powder of the alkyl methacrylate polymer (A) is excellent in pulverization into primary particles. More preferably.

  As the alkyl methacrylate polymer (A) of the present invention, the same polymer may be used alone, or two or more polymers having different compositions, molecular weights, particle diameters and the like may be used in combination.

The mass average molecular weight of the alkyl methacrylate polymer (A) of the present invention is preferably 1,000 to 3,000,000, more preferably 3,000 to 500,000, and a thermoplastic resin. From the viewpoint of the dispersibility of polytetrafluoroethylene, it is more preferably 5,000 to 100,000, and most preferably 10,000 to 50,000.
When the mass molecular weight of the alkyl methacrylate polymer (A) is 1,000 or more, the dispersibility improver is excellent in powder handleability. Moreover, when the mass molecular weight of the alkyl methacrylate polymer (A) is 3,000,000 or less, the dispersibility of polytetrafluoroethylene in the thermoplastic resin is excellent.

  The method for adjusting the mass average molecular weight is not particularly limited, and examples thereof include a method for adjusting the initiator amount and a method for adjusting the chain transfer agent amount.

Examples of the chain transfer agent include mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, n-hexyl mercaptan, n-butyl mercaptan; carbon tetrachloride, ethylene bromide And halogen compounds such as α-methylstyrene dimer.
These chain transfer agents may be used individually by 1 type, and may use 2 or more types together.

  The amount of the chain transfer agent used can be appropriately adjusted according to the weight average molecular weight of the alkyl methacrylate polymer (A), the type of chain transfer agent used, the composition ratio of the monomers, and the like.

The dispersibility improver of the present invention contains the alkyl methacrylate polymer (A) of the present invention. The dispersibility improver of the present invention plays a role of increasing the dispersibility of the polytetrafluoroethylene component when the polytetrafluoroethylene-containing modifier is mixed with the thermoplastic resin.
The dispersibility improver of the present invention may further contain additives such as a filler, a flame retardant, a stabilizer, a lubricant, and a foaming agent, as necessary. As an additive, the thing similar to the additive mix | blended with the thermoplastic resin composition of this invention mentioned later can be used.

  The polytetrafluoroethylene-containing modifier contains polytetrafluoroethylene, and the content, molecular weight, form, and the like of polytetrafluoroethylene are not particularly limited. A polytetrafluoroethylene-containing modifier is a modifier that is added for the purpose of improving the molding processability of a thermoplastic resin, imparting a drip-preventing ability during combustion, and the like.

Examples of the polytetrafluoroethylene-containing modifier include, for example, “methabrene A-3000”, “same A-3700”, “same A-3750”, “same A-3800” (trade name, manufactured by Mitsubishi Rayon Co., Ltd.). And modified polytetrafluoroethylene such as “Brendex 449” (trade name, manufactured by Chemtura).
Among these polytetrafluoroethylene-containing modifiers, from the viewpoint of dispersibility of polytetrafluoroethylene, “methabrene A-3000”, “same A-3700”, “same A-3750”, “same A-3800” An acrylic modified polytetrafluoroethylene such as “trade name, manufactured by Mitsubishi Rayon Co., Ltd.” is preferable.

  The thermoplastic resin composition of the present invention includes the dispersibility improver of the present invention, a polytetrafluoroethylene-containing modifier, and a thermoplastic resin.

Examples of the thermoplastic resin include polyolefin resin, polyvinyl chloride resin, polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, and polyamide resin.
Among these thermoplastic resins, a polyolefin resin is preferable because it is excellent in appearance of a molded product obtained by a remarkable effect of improving moldability and high dispersibility.

  The polyolefin resin refers to a homopolymer of an olefin monomer or a copolymer having an olefin monomer as a main component. Examples of the olefin monomer include ethylene, propylene, 1-butene, 1-hexene, 1-decene, 1-octene, and 4-methyl-1-pentene. Specific examples of homopolymers of olefin monomers or copolymers mainly composed of olefin monomers include, for example, low density polyethylene, high density polyethylene, polypropylene, ethylene / propylene copolymer, polymethyl Examples include pentene, polybutene, and mixed resins thereof.

The content of the dispersibility improver in the thermoplastic resin composition of the present invention is 0.01 to 20 parts by mass with respect to 100 parts by mass in total of the thermoplastic resin and the polytetrafluoroethylene-containing modifier. Preferably, it is 0.1-10 mass parts, More preferably, it is 0.2-5 mass parts.
When the content of the dispersibility improver is 0.01 parts by mass or more, the dispersibility of polytetrafluoroethylene in the thermoplastic resin is excellent. Moreover, the dispersibility of polytetrafluoroethylene can be improved, without changing the basic characteristic of a thermoplastic resin as content of a dispersibility improvement agent is 20 mass parts or less.

As a composition ratio of the thermoplastic resin and the polytetrafluoroethylene-containing modifier in the thermoplastic resin composition of the present invention, the thermoplastic resin is 100% by mass in total of the thermoplastic resin and the polytetrafluoroethylene-containing modifier. 70 to 99.95% by mass, polytetrafluoroethylene-containing modifier is preferably 0.05 to 30% by mass, thermoplastic resin is 80 to 99.9% by mass, polytetrafluoroethylene-containing modifier Is more preferably 0.1 to 20% by mass.
When the thermoplastic resin is 70% by mass or more, the dispersibility of polytetrafluoroethylene in the thermoplastic resin is excellent. Moreover, the moldability of a thermoplastic resin composition will improve that a thermoplastic resin is 99.95 mass% or less.
When the polytetrafluoroethylene-containing modifier is 0.05% by mass or more, the moldability of the thermoplastic resin composition is improved. Further, when the polytetrafluoroethylene-containing modifier is 30% by mass or less, the dispersibility of polytetrafluoroethylene in the thermoplastic resin is excellent.

As a blending method of the thermoplastic resin composition of the present invention, known melt kneading such as extrusion kneading and roll kneading can be used.
The melt kneading method is not particularly limited, and the dispersibility improver of the present invention may be simultaneously melt kneaded with the dispersibility improver of the present invention, the polytetrafluoroethylene-containing modifier and the thermoplastic resin. In addition, a polytetrafluoroethylene-containing modifier may be blended and melt-kneaded in a resin composition obtained by previously melt-kneading a thermoplastic resin.
The melt kneading temperature can be appropriately set according to the type of the thermoplastic resin. When the thermoplastic resin is a polyolefin resin, the melt kneading temperature is preferably 160 to 280 ° C, and more preferably 180 to 240 ° C.

  The thermoplastic resin composition of the present invention may further contain additives such as a filler, a flame retardant, a stabilizer, a lubricant, and a foaming agent, if necessary.

Examples of the filler include calcium carbonate, talc, glass fiber, carbon fiber, magnesium carbonate, mica, kaolin, calcium sulfate, barium sulfate, titanium white, white carbon, carbon black, magnesium hydroxide, and aluminum hydroxide. .
These fillers may be used individually by 1 type, and may use 2 or more types together.

Flame retardants include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, cresyl phenyl phosphate, octyl diphenyl phosphate, diisopropylphenyl phosphate, tris (chloroethyl) phosphate , Alkoxy-substituted bisphenol A bisphosphate, hydroquinone bisphosphate, resorcin bisphosphate, trioxybenzene triphosphate, "CR-733S", "CR-741", "PX-200" (trade name, Daihachi Chemical Industry Co., Ltd.) Phosphate compounds such as tetrabromobisphenol A, decabromodiphenyl oxide, hexabromocyclo Decane, octabromodiphenyl ether, bistribromophenoxyethane, ethylenebistetrabromophthalimide, tribromophenol, halogenated epoxy oligomer obtained by reaction of halogenated bisphenol A and epihalohydrin, carbonate containing halogenated bisphenol A as a constituent Halogen-containing compounds such as oligomers, halogenated polystyrenes, chlorinated polyolefins, and polyvinyl chloride; metal hydroxides; metal oxides; sulfamic acid compounds.
These flame retardants may be used alone or in combination of two or more.

Stabilizers include pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5- Phenolic antioxidants such as methyl-4-hydroxyphenyl) propionate]; Phosphorous antioxidants such as tris (monononylphenyl) phosphite and tris (2,4-di-t-butylphenyl) phosphite; Sulfur-based antioxidants such as lauryl thiodipropionate; hindered amines such as “Tinuvin-770” (trade name, manufactured by Ciba Japan Co., Ltd.), “Adeka Stub LA-57” (trade name, manufactured by ADEKA Corp.) Light stabilizer, “Tinubin 1577FF” (trade name, manufactured by Ciba Japan Co., Ltd.), “ADEKA STAB LA-32” (product) Include ultraviolet absorbers such as (Ltd.) ADEKA Corporation).
These stabilizers may be used individually by 1 type, and may use 2 or more types together.

Examples of the lubricant include sodium, calcium or magnesium salts of lauric acid, palmitic acid, oleic acid or stearic acid.
These lubricants may be used individually by 1 type, and may use 2 or more types together.

As the foaming agent, known foaming agents such as inorganic foaming agents, volatile foaming agents, and decomposable foaming agents can be used.
Examples of the inorganic foaming agent include carbon dioxide, air, and nitrogen.
Examples of volatile blowing agents include aliphatic hydrocarbons such as propane, n-butane, i-butane, pentane and hexane; cyclic aliphatic hydrocarbons such as cyclobutane and cyclopentane; trichlorofluoromethane and dichlorodifluoromethane. Halogenated hydrocarbons such as dichlorotetrafluoroethane, methyl chloride, ethyl chloride, and methylene chloride.
Examples of the decomposable foaming agent include azodicarbonamide, dinitrosopentamethylenetetramine, azobisisobutyronitrile, and sodium bicarbonate.
The addition amount of the foaming agent is preferably 0.1 to 25 parts by mass with respect to 100 parts by mass of the thermoplastic resin composition, although it depends on the type of the foaming agent.
These foaming agents may be used individually by 1 type, and may use 2 or more types together.

  The molded article of the present invention is obtained by molding the thermoplastic resin composition of the present invention.

  As a molding method of the molded body of the present invention, a known molding method can be used, and examples thereof include extrusion molding, injection molding, calendar molding, blow molding, thermoforming, foam molding, and melt spinning.

  The molded body of the present invention is suitable for a sheet material such as an optical sheet, a film material such as a food film, an automobile member, a household appliance member, a medical member, and a building member.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
In the examples, “parts” and “%” indicate “parts by mass” and “% by mass”.

(1) Mass average molecular weight Gel permeation chromatography (model name “HLC-8220”, manufactured by Tosoh Corp.), column (trade name “TSK”) using the tetrahydrofuran-soluble content of the alkyl methacrylate polymer (A) as a sample. -GEL SUPER HZM-M "(manufactured by Tosoh Corporation) was used under the conditions of eluent tetrahydrofuran and measurement temperature 40 ° C.
The mass average molecular weight was determined from a calibration curve using standard polystyrene.

(2) Powder handling property The dispersibility improver was passed through an 8-mesh sieve, the amount of the sample passed was determined, and the powder handling property was evaluated according to the following criteria.
○: A sieve passing amount is 80% or more Δ: A sieve passing amount is 50% or more and less than 80% ×: A sieve passing amount is less than 50%

(3) Melt tension (moldability)
Using a thermoplastic rheometer (model name “Twin Capillary Rheometer RH-7”, manufactured by ROSAND), the die is φ1 mm, L / D = 16, temperature 190 ° C. A certain amount (0.54 cm ³ / min) was extruded, and the strand was taken up at a constant speed (3 m / min).
The melt tension of the thermoplastic resin composition is one of the indicators for determining molding processability such as thermoformability, blow moldability, and foam moldability, and improvement in melt tension can be regarded as improvement in moldability.

(4) Number of surface irregularities (appearance)
The number of foreign substances present in the molded body (film) was evaluated. The evaluation procedure is to visually mark the irregularities seen on the surface of the film 10m, observe the marked irregularities using a stereomicroscope, and count only the irregularities derived from the aggregates of polytetrafluoroethylene. The average value of the number of foreign matters per meter was obtained.
In addition, it can be confirmed by an infrared absorption spectrum measurement whether an unevenness | corrugation originates in the aggregate of polytetrafluoroethylene.
The number of surface irregularities of the molded body is one of the indicators for judging the dispersibility of polytetrafluoroethylene in the thermoplastic resin and the surface appearance of the molded body. The smaller the number of surface irregularities of the molded body, the more the polytetrafluoroethylene Excellent dispersibility and surface appearance of the molded product.

[Production Example 1] Synthesis of polytetrafluoroethylene-containing modifier (Z) A separable flask equipped with a thermometer, a nitrogen introduction tube, a cooling tube and a stirrer was charged with 230 parts of ion exchange water as a dispersion medium and dodecyl as an emulsifier 2.5 parts of sodium benzenesulfonate, 0.0002 part of ferrous sulfate, 0.0006 part of disodium ethylenediaminetetraacetate and 0.48 part of ascorbic acid were charged, and the inside of the container was purged with nitrogen. Next, the internal temperature was raised to 73 ° C., and 0.2 parts of cumene hydroperoxide as a polymerization catalyst, 1 part of n-octyl mercaptan, 98 parts of i-butyl methacrylate and 2 parts of n-butyl acrylate as a chain transfer agent were used. The monomer mixture was added dropwise over 1 hour and held at the same temperature for 1 hour to obtain an alkyl methacrylate polymer latex.
Subsequently, 165 parts of polytetrafluoroethylene latex (trade name “Fluon AD 939L”, manufactured by Asahi Glass Co., Ltd., solid content: 60% by mass) was added dropwise and stirred for 1 hour. The obtained latex was cooled to 25 ° C., dropped in 750 parts of 80 ° C. hot water containing 0.35 part of aluminum sulfate, and then heated to 90 ° C. for coagulation. The obtained coagulated product was separated and washed, and then dried at 60 ° C. for 12 hours to obtain a polytetrafluoroethylene-containing modifier (Z).

[Example 1]
In a separable flask equipped with a thermometer, a nitrogen introduction tube, a cooling tube and a stirring device, 225 parts of ion-exchanged water as a dispersion medium, 2.5 parts of sodium dodecylbenzenesulfonate as an emulsifier, 0.0002 part of ferrous sulfate, 0.0006 part of ethylenediaminetetraacetic acid disodium and 0.48 part of ascorbic acid were charged, and the inside of the container was replaced with nitrogen. Next, the internal temperature was raised to 73 ° C., and 0.2 parts of cumene hydroperoxide as a polymerization catalyst, 1 part of n-octyl mercaptan, 98 parts of i-butyl methacrylate and 2 parts of n-butyl acrylate as a chain transfer agent were used. The monomer mixture was added dropwise over 1 hour, and further maintained at the same temperature for 1 hour to obtain an alkyl methacrylate polymer (A1) latex.
The obtained latex was cooled to 25 ° C., dropped in 500 parts of 70 ° C. hot water containing 5 parts of calcium acetate, and then heated to 90 ° C. for coagulation. The obtained coagulated product was separated and washed, and then dried at 60 ° C. for 12 hours to obtain an alkyl methacrylate polymer (A1). The obtained alkyl methacrylate polymer (A1) was used as a dispersibility improver (1).

[Examples 2 to 5, Comparative Example 1]
Except for changing the monomer mixture and the amount of chain transfer agent to the composition shown in Table 1, polymerization and recovery were carried out in the same manner as in Example 1 to obtain alkyl methacrylate polymers (A2) to (A5), (A7). ) The obtained alkyl methacrylate polymers (A2) to (A5) and (A7) were designated as dispersibility improvers (2) to (5) and (7).

[Example 6]
225 parts of deionized water as a dispersion medium, 2.5 parts of sodium dodecylbenzenesulfonate as an emulsifier, 80 parts of 2-ethylhexyl methacrylate, 18 parts of methyl methacrylate and 2 parts of n-butyl acrylate in a homomixer at 10,000 rpm Then, the mixture was passed through a homogenizer twice at a pressure of 30 MPa to obtain a preliminary dispersion. After adding 0.2 parts of cumene hydroperoxide as a polymerization catalyst and 1 part of n-octyl mercaptan as a chain transfer agent to this preliminary dispersion and stirring sufficiently, a thermometer, a nitrogen introduction pipe, a cooling pipe and a stirring device were added. The prepared separable flask was charged and heated to 60 ° C. When the temperature reached 60 ° C., a solution in which 0.0002 part of ferrous sulfate, 0.0006 part of disodium ethylenediaminetetraacetate and 0.48 part of ascorbic acid was dissolved in 2 parts of ion-exchanged water was added, and polymerization was performed. It was started and held at 60 ° C. for 2 hours to obtain an alkyl methacrylate polymer (A6) latex.
The obtained latex was cooled to 25 ° C., dropped in 500 parts of 70 ° C. hot water containing 5 parts of calcium acetate, and then heated to 90 ° C. for coagulation. The obtained coagulated product was separated and washed, and then dried at 60 ° C. for 12 hours to obtain an alkyl methacrylate polymer (A6). The obtained alkyl methacrylate polymer (A6) was used as a dispersibility improver (6).

  Table 1 shows the weight average molecular weights of the alkyl methacrylate polymers (A1) to (A7) and the powder handling properties of the dispersibility improvers (1) to (7).

尚、表中の略号は、以下の化合物を示す。
ｉ−ＢＭＡ：ｉ−ブチルメタクリレート
ｎ−ＢＭＡ：ｎ−ブチルメタクリレート
ＥＨＭＡ ：２−エチルヘキシルメタクリレート
ＭＭＡ ：メチルメタクリレート
ｎ−ＢＡ ：ｎ−ブチルアクリレート
ｎ−ＯＭ ：ｎ−オクチルメルカプタン
ＤＢＳＮａ：ドデシルベンゼンスルホン酸ナトリウム

In addition, the symbol in a table | surface shows the following compounds.
i-BMA: i-butyl methacrylate n-BMA: n-butyl methacrylate EHMA: 2-ethylhexyl methacrylate MMA: methyl methacrylate n-BA: n-butyl acrylate n-OM: n-octyl mercaptan DBSNa: sodium dodecylbenzenesulfonate

[Example 7]
99.5 parts of a polypropylene resin “NOVATEC-PP FY-4” (trade name, manufactured by Nippon Polypro Co., Ltd., melt flow rate: 5 g / 10 min) as a thermoplastic resin, and “polytetrafluoroethylene-containing modifier” 0.5 parts of METABLEN A-3000 "(trade name, manufactured by Mitsubishi Rayon Co., Ltd.) and 1 part of the dispersibility improver (1) were blended and mixed by hand blending. Then, extrusion molding was performed with a screw rotation speed of 200 rpm and a cylinder temperature of 200 ° C. in a φ30 mm same-direction twin screw extruder (model name “BT-30”, manufactured by Plastic Engineering Laboratory Co., Ltd., L / D = 30). Thus, a thermoplastic resin composition was obtained. The melt tension of the thermoplastic resin composition thus obtained was measured by the above method.
The obtained thermoplastic resin composition was dried at 80 ° C. for 12 hours, and a single-screw extruder (model name “GM-30”, manufactured by GM Engineering, L / D = 30) attached with a T-die. The film was formed to a film thickness of 500 μm and a film width of 10 cm under the conditions of a screw rotation speed of 20 rpm, a cylinder temperature of 200 ° C., and a T die temperature of 210 ° C. to obtain a molded body (film).

[Examples 8 to 19, Comparative Examples 2 to 8, Reference Example 1]
Except having changed the composition into the compositions shown in Tables 2 to 4, molding and film formation were performed in the same manner as in Example 7 to obtain a molded body.

  Tables 2 to 4 show the melt tension of the thermoplastic resin compositions obtained in Examples 8 to 19, Comparative Examples 2 to 8, and Reference Example 1 and the number of surface irregularities of the molded body.

In addition, the symbol in a table | surface shows the following compounds and goods.
PTFE: Polytetrafluoroethylene (X): Metabrene A-3000 (trade name, manufactured by Mitsubishi Rayon Co., Ltd.)
(Y): Metablen A-3800 (trade name, manufactured by Mitsubishi Rayon Co., Ltd.)
(Z): Polytetrafluoroethylene-containing modifier synthesized in Production Example 1 (Z)

As is apparent from Tables 2 to 4, in Examples 7 to 19 in which the dispersibility improvers (1) to (6) containing the alkyl methacrylate polymers (A1) to (A6) of the present invention were blended, obtained. The melt tension of the thermoplastic resin composition and the appearance of the resulting molded product were excellent.
On the other hand, in Comparative Examples 3, 6, and 8 that did not contain the dispersibility improver of the present invention, the appearance of the obtained molded article was inferior. In Comparative Examples 2, 5, and 7, in which a dispersibility improver (7) containing an alkyl methacrylate-based polymer (A7) containing methyl methacrylate as a main component whose carbon number of the alkyl group is outside the scope of the present invention is blended. The appearance of the resulting molded product was inferior. Further, in Comparative Example 4 not containing the polytetrafluoroethylene-containing modifier and the dispersibility improver of the present invention, and in Reference Example 1 not containing the polytetrafluoroethylene-containing modifier, melting of the resulting thermoplastic resin composition Inferior in tension.

  The molded body of the present invention is suitable for a sheet material such as an optical sheet, a film material such as a food film, an automobile member, a household appliance member, a medical member, and a building member.

Claims (4)

The content of the alkyl methacrylate (a1) unit having an alkyl group having 2 or more carbon atoms, which increases the dispersibility of the polytetrafluoroethylene-containing modifier, which is an acrylic-modified polytetrafluoroethylene, in the polyolefin-based resin is 50% by mass. A dispersibility improver comprising the alkyl methacrylate polymer (A) as described above (however, the modifier is not included).   The dispersibility improver according to claim 1, wherein the alkyl methacrylate (a1) unit having an alkyl group having 2 or more carbon atoms is an i-butyl methacrylate unit.   The dispersibility improver according to claim 1 or 2, wherein the alkyl methacrylate polymer (A) has a mass average molecular weight of 5,000 to 100,000.   The manufacturing method of the polyolefin resin composition which melt-kneads the dispersibility improving agent of Claims 1-3, a polytetrafluoroethylene containing modifier, and polyolefin resin.