JPH11209549A - Mixed powder including polytetrafluoroethylene, thermoplastic resin composition containing the same and molding product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mixed powder including a polytetrafluoroethylene effective for improvement of the molding processability of a thermoplastic resin and having a good dispersibility of the polytetrafluoroethylene in a thermoplastic resin. SOLUTION: This mixed powder including a polytetrafluoroethylene comprises (A) polytetrafluoroethylene particles having <=10 μm particle diameters and (B) an organic polymer particles and is characterized by having substantially two or more loss tangent (tanδ) peaks of the organic polymer particles B in a dynamic viscoelasticity measurement of the mixed powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polytetrafluoroethylene-containing mixed powder excellent in dispersibility for significantly improving the moldability of a thermoplastic resin, a thermoplastic resin composition containing the same, and a thermoplastic resin composition obtained therefrom. Related to molded articles.

[0002]

2. Description of the Related Art Polytetrafluoroethylene (PTF)
E) is widely used as a coating agent because it has excellent heat resistance, chemical resistance, and electrical insulation, and has unique surface characteristics such as water / oil repellency, non-adhesion, and self-lubricating property. In addition, because of its high crystallinity and small intermolecular force, it has the property of forming fibers with slight stress.When blended with thermoplastic resin, its moldability, mechanical properties, etc. are improved, making it suitable for thermoplastic resins. It is also used as an additive.

For example, JP-A-5-214184 and JP-A-6-306212 disclose resin compositions obtained by blending polytetrafluoroethylene with polyolefin. JP-A-7-324147 discloses a method for producing a polyolefin-based resin composition in which polytetrafluoroethylene and a dispersion medium powder are mixed under high shear, polytetrafluoroethylene is preliminarily fiberized, and then mixed with polyolefin. It has been disclosed.

[0004]

However, polytetrafluoroethylene has poor dispersibility with respect to a general thermoplastic resin containing no halogen atom.
The simple blends described in JP-A-214184 and JP-A-6-306212 do not uniformly disperse, and have the disadvantage that the surface appearance of the obtained molded article is significantly reduced.

Also, it is difficult to fiberize all polytetrafluoroethylene by shearing force even by a method as described in JP-A-7-324147.
The fiberized polytetrafluoroethylene also aggregates in the matrix resin, and a uniform composition cannot be obtained.

That is, all of these methods have a problem in dispersibility of polytetrafluoroethylene in a thermoplastic resin, and a large amount of polytetrafluoroethylene is required to exhibit the above-mentioned useful properties. There was a disadvantage.

An object of the present invention is to provide a polytetrafluoroethylene-containing mixed powder which is effective for improving the moldability of a thermoplastic resin and has good dispersibility of polytetrafluoroethylene in the thermoplastic resin. It is in.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that polytetrafluoroethylene comprising polytetrafluoroethylene particles (A) having a particle diameter of 10 μm or less and organic polymer particles (B). An ethylene-containing mixed powder, wherein the dynamic viscoelasticity measurement of the mixed powder has substantially two loss tangent (tan δ) peaks of the organic polymer particles (B). By adding the mixed powder to the thermoplastic resin, the tetrafluoroethylene-containing mixed powder is found to have good moldability and excellent dispersibility of polytetrafluoroethylene in the thermoplastic resin. Reached the present invention.

That is, the gist of the present invention is that the particle diameter is 10 μm.
A polytetrafluoroethylene-containing mixed powder composed of the following polytetrafluoroethylene particles (A) and organic polymer particles (B), and in the dynamic viscoelasticity measurement of the mixed powder, Loss tangent (tan) of particle (B)
δ) Polytetrafluoroethylene-containing mixed powder characterized by having substantially two peaks, a thermoplastic resin composition containing the same, and a molded article obtained therefrom.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polytetrafluoroethylene (A) used in the present invention must have a particle size not exceeding 10 μm and should not be formed into an aggregate.
The particles are preferably 0 μm particles. Such polytetrafluoroethylene particles are dispersed in water containing an emulsifier and the like, and this aqueous dispersion of polytetrafluoroethylene particles is prepared by emulsifying a tetrafluoroethylene monomer by emulsion polymerization using a fluorinated surfactant. Obtained by polymerization.

In the emulsion polymerization of polytetrafluoroethylene particles, copolymer components such as hexafluoropropylene, chlorotrifluoroethylene, fluoroalkylethylene, and perfluoroalkylvinyl ether are contained as long as the properties of polytetrafluoroethylene are not impaired. Fluorinated olefins and fluorinated alkyl (meth) acrylates such as perfluoroalkyl (meth) acrylate can be used. The content of the copolymer component is preferably 10% by weight or less based on polytetrafluoroethylene.

Commercially available raw materials for the polytetrafluoroethylene particle dispersion include Fluon AD-1, AD-936, CD-123 manufactured by Asahi ICI Fluoropolymers, and Polyflon D-1, D-2 manufactured by Daikin Industries, Ltd. Teflon 30J manufactured by Du Pont-Mitsui Fluorochemicals Co., Ltd. can be cited as a typical example.

The organic polymer particles (B) used in the present invention
Is preferably composed of two or more polymers or copolymers. The polymer or copolymer is obtained by emulsion polymerization, in particular, by polymerizing a monomer or monomer mixture that can be emulsion-polymerized by a radical method. The two or more polymers or copolymers to be used are those having a relatively high glass transition temperature from the viewpoint of storage and handleability of the polytetrafluoroethylene-containing mixed powder and those which are blended with the thermoplastic resin (C). It is preferable to include those having an affinity for the thermoplastic resin (C) from the viewpoint of dispersibility of the polytetrafluoroethylene. Particle (B) must have substantially two or more loss tangent (tan δ) peaks.

This is because the thermoplastic resin (C)
A polymer or copolymer having an affinity for, and a polymer or copolymer that improves the storage and handling properties of the polytetrafluoroethylene-containing mixed powder are present separately. Accordingly, the object of providing a polytetrafluoroethylene-containing mixed powder which is excellent in dispersibility of polytetrafluoroethylene in the thermoplastic resin (C) and is effective for improving molding processability of the thermoplastic resin is achieved. .

At least one of the two or more polymers or copolymers used in the present invention is a thermoplastic resin (C) blended with a polytetrafluoroethylene-containing mixed powder.
The other is selected from the viewpoint of improving the storage and handling properties of the polytetrafluoroethylene-containing mixed powder.

Specific examples of the monomer for producing the organic polymer particles (B) include styrene, p-methylstyrene, o-methylstyrene, p-chlorostyrene, o-chlorostyrene, and p-methoxy. Styrene, o-methoxystyrene, 2,4-dimethylstyrene, styrene monomers such as α-methylstyrene, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate,
Butyl acrylate, butyl methacrylate, acrylic acid-
(Meth) acrylic esters such as 2-ethylhexyl, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridodecyl acrylate, tridodecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate Monomers, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether, vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate, and ethylene Olefin monomers such as propylene, isobutylene and the like, and diene monomers such as butadiene, isoprene and dimethylbutadiene, but are not limited thereto.
Preferably, organic polymer particles (B) can be obtained by using two or more kinds of polymers or copolymers of these monomers.

When the thermoplastic resin (C) in which the polytetrafluoroethylene-containing mixed powder of the present invention is blended is a polyolefin, styrene-based monomers are preferred among these monomers from the viewpoint of affinity. And (meth) acrylate monomers and olefin monomers. Particularly preferred are long-chain alkyl (meth) acrylate monomers having 12 or more carbon atoms. The organic polymer particles (B) preferably contain these monomers in an amount of 20% by weight or more.

When the thermoplastic resin (C) in which the polytetrafluoroethylene-containing mixed powder of the present invention is blended is polymethyl methacrylate, (meth) is preferred among these monomers from the viewpoint of affinity. Acrylic ester monomers can be mentioned, and it is preferable that these monomers are contained in the organic polymer particles (B) in an amount of 20% by weight or more.

When the thermoplastic resin (C) in which the polytetrafluoroethylene-containing mixed powder of the present invention is blended is a polyester, a styrene-based monomer is preferred among these monomers from the viewpoint of affinity. And (meth) acrylate-based monomers, and the organic polymer particles (B) preferably contain 20% by weight or more of these monomers. It is particularly preferred that the organic polymer particles (B) contain 1% by weight or more of a (meth) acrylate monomer having an epoxy group.

On the other hand, from the viewpoint of improving the storage and handleability of the polytetrafluoroethylene-containing mixed powder of the present invention, styrene, p-methylstyrene, o-methyl Styrene, p-chlorostyrene, o-chlorostyrene, p
-Methoxystyrene, 2,4-dimethylstyrene, α-
Styrene monomers such as methylstyrene, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate,
2-ethylhexyl acrylate, methacrylic acid-2-
Acrylic ester monomers such as ethylhexyl, dodecyl acrylate, dodecyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; vinyl methyl ether; vinyl ethyl ether; Vinyl ether monomers, vinyl acetate, vinyl carboxylate monomers such as vinyl butyrate, ethylene, propylene,
It can be selected from olefin monomers such as isobutylene and diene monomers such as butadiene, isoprene and dimethylbutadiene. These monomers can be used alone or in combination of two or more.

In the present invention, a monomer selected from the viewpoint of affinity with the thermoplastic resin (C) and a monomer selected from the viewpoint of storage and handling of the mixed powder are simultaneously polymerized to obtain polytetrafluoroethylene. The polytetrafluoroethylene particle dispersion may be mixed with the fluoroethylene particle dispersion or a polymer or copolymer containing a monomer selected in advance from the viewpoint of affinity with the thermoplastic resin (C). In the dispersion thus prepared, a monomer for improving the storage and handling of the mixed powder may be polymerized. Dispersibility of polytetrafluoroethylene and
The latter is preferred from the viewpoint of storage and handling of the mixed powder.

The method for producing the aqueous dispersion of the organic polymer particles (B) used in the present invention is not particularly limited, but examples thereof include an emulsion polymerization method using an ionic emulsifier, and an ionic polymerization initiator. The soap-free emulsion polymerization method used can be exemplified.

As the ionic emulsifier, any of an anionic emulsifier, a cationic emulsifier and an amphoteric ionic emulsifier may be used. If desired, a nonionic emulsifier may be used in combination with these ionic emulsifiers.

Specific examples of anionic emulsifiers include fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, sulfates of aliphatic amines and amides, aliphatic alcohol phosphates, and dibasic acid salts. Examples include fatty acid ester sulfonates, alkylallyl sulfonates, and formalin condensate naphthalene sulfonates.

Specific examples of the cationic emulsifier include aliphatic amine salts, quaternary ammonium salts, and alkylpyridium salts.

Specific examples of the amphoteric emulsifier include alkyl betaine.

Examples of the ionic polymerization initiator include persulfates (for example, potassium persulfate and ammonium persulfate), azobis (isobutyronitrile sulfonate), 4,4'-
Anionic polymerization initiators such as azobis (4-cyanovaleric acid), dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride,
Cationic polymerization initiators such as 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride and 2,2′-azobisisobutylamide dihydrate can be exemplified. .

The particle size d of the organic polymer particles (B) used in the present invention is not particularly limited, but from the viewpoint of the stability of the state of aggregation with the polytetrafluoroethylene particles (A), Tetrafluoroethylene particles (A)
Is preferably in the range of the following formula.

0.1D <d <10D The polytetrafluoroethylene-containing mixed powder of the present invention
The aqueous dispersion can be poured into hot water in which a metal salt such as calcium chloride or magnesium sulfate is dissolved, salted out and coagulated, and then dried or powdered by spray drying. The polytetrafluoroethylene-containing mixed powder is composed of particles in which polytetrafluoroethylene particles (A) and organic polymer particles (B) are aggregated due to a difference in surface charge, and each single particle remaining without aggregation. Including. The agglomerated particles have a structure in which the polytetrafluoroethylene particles (A) and the organic polymer particles (B) are integrated, and the morphology varies depending on the mixing ratio and the particle diameter of the two particles. There can be. That is, there is a form in which the organic polymer particles (B) entirely or partially surround the polytetrafluoroethylene particles (A). At this time, if only the polytetrafluoroethylene particles (A) aggregate to form an aggregate of 10 μm or more, it is not preferable from the viewpoint of dispersibility in the thermoplastic resin (C).

The content of polytetrafluoroethylene in the polytetrafluoroethylene-containing mixed powder of the present invention is preferably 0.1% by weight to 90% by weight.

The thermoplastic resin (C) used in the present invention includes polyolefin resins such as polyethylene, polypropylene and ethylene-propylene copolymer, polyethylene terephthalate (PET), polyethylene naphthalate, and the like.
Polyester resin such as polycyclohexane terephthalate, polybutylene terephthalate (PBT), polybutylene naphthalate, polycarbonate (PC), butadiene rubber graft copolymer (for example, ABS resin), acrylic rubber graft copolymer, silicone-acryl composite rubber graft Copolymer, ethylene propylene rubber graft copolymer, styrene resin such as HIPS, AS, vinyl chloride resin, polyacetal resin, polyphenylene sulfide resin, polyphenylene ether resin (PP
E), polyamide resin (PA) such as nylon 6, nylon 66, acrylic resin such as PMMA, PET / PB
T, PC / PBT, PBT / ABS, PC / ABS, P
A / ABS, PPE / PBT, PPE / HIPS, PP
E / PA and the like, and particularly, polyolefin resin,
Further, a polypropylene resin is preferred.

The polytetrafluoroethylene-containing mixed powder of the present invention is excellent in the dispersibility of polytetrafluoroethylene in the thermoplastic resin (C), and the polytetrafluoroethylene-containing mixed powder can be mixed with the thermoplastic resin (C). In the processing of the thermoplastic resin composition, the tension at the time of melting increases, the take-up property at the time of calendering, the drawdown of the molten resin at the time of thermoforming or blow molding, and the connection of the cells at the time of foam molding. Foaming and the like are improved, and the processability of calendering, thermoforming, blow molding, and foam molding is improved. In addition, the discharge amount during extrusion molding and the surface condition of extruded products such as sheets and films are improved, and the extrudability is improved.

In the present invention, the blending amount of the polytetrafluoroethylene-containing mixed powder is selected from thermoplastic resin (C)
The range is preferably 0.001 to 50 parts by weight based on 100 parts by weight. The amount of polytetrafluoroethylene is preferably in the range of 0.0001 to 40 parts by weight based on 100 parts by weight of the thermoplastic resin (C).

The thermoplastic resin composition of the present invention is obtained by mixing the thermoplastic resin (C) with a mixed powder containing polytetrafluoroethylene. As a mixing method, an appropriate method such as a screw-type extruder in which the mixture is simultaneously subjected to shear compression or kneading between heating rolls may be used. Also, after the master batch is prepared, multi-stage mixing such as further adding and mixing the remaining thermoplastic resin (C) is also possible.

Further, a filler can be added to the thermoplastic resin composition of the present invention. The amount of the filler is 0.1 parts by weight based on 100 parts by weight of the thermoplastic resin (C).
４００400 parts by weight, rigidity and heat resistance are improved by the addition of this filler, and processability such as prevention of adhesion to a roll surface in calendering is improved.
Further, cost reduction can be achieved. If the amount is less than 0.1 part by weight, the effect of improving the rigidity is not sufficient, and if it exceeds 400 parts by weight, the surface properties tend to decrease. This range is more preferably from 1 to 350 parts by weight, even more preferably from 1 to 3 parts by weight.
00 parts by weight.

The filler used in the present invention includes calcium carbonate, talc, glass fiber, carbon fiber, magnesium carbonate, mica, kaolin, calcium sulfate, barium sulfate, titanium white, white carbon, carbon black, ammonium hydroxide, water Representative examples include magnesium oxide and aluminum hydroxide. Calcium carbonate, talc and the like are preferred.

The thermoplastic resin composition of the present invention may further contain additives such as stabilizers, lubricants and flame retardants, if necessary. As the stabilizer, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4)
-Hydroxyphenyl) propionate], phenolic stabilizers such as triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], tris (monononylphenyl) phosphite, tris Phosphorus stabilizers such as (2,4-di-t-butylphenyl) phosphite, sulfur stabilizers such as dilauryl thiodipropionate, and lubricants include lauric acid, palmitic acid, oleic acid and stearic acid. Sodium, calcium or magnesium salts and flame retardants include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, Phosphate compounds such as polyphosphates such as phenyl phosphate, octyl diphenyl phosphate, diisopropylphenyl phosphate, tris (chloroethyl) phosphate, alkoxy-substituted bisphenol A bisphosphate, hydroquinone bisphosphate, resorcin bisphosphate, and trioxybenzene triphosphate; tetrabromo Bisphenol A, decabromodiphenyl oxide, hexabromocyclododecane, octabromodiphenyl ether, bistribromophenoxyethane, ethylene bistetrabromophytylimide, tribromophenol, various halogenated epoxies obtained by the reaction of halogenated bisphenol A with epihalohydrin Construct oligomer, halogenated bisphenol A Min to carbonate oligomers, halogenated polystyrenes, chlorinated polyolefins and halogen-containing compounds such as polyvinyl chloride, metal hydroxides, metal oxides, sulfamic acid compounds, and the like as typical examples respectively.

Since the thermoplastic resin composition of the present invention has excellent dispersibility of polytetrafluoroethylene, its processability, rigidity, surface appearance, etc. are greatly improved, and molded articles are produced by various processing methods. And a useful molded article can be obtained.

Examples of the processing method of the thermoplastic resin composition of the present invention include calender molding, extrusion molding, thermoforming, blow molding, injection molding, foam molding, and melt spinning.

Useful molded articles obtained by using the thermoplastic resin composition of the present invention include sheets, films,
Thermoformed articles, hollow molded articles, injection molded articles, foam molded articles, fibers and the like can be mentioned.

[0041]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

In each description, "parts" indicates parts by weight.

The methods for measuring various physical properties used in the examples are as follows.

(1) Measurement of dynamic viscoelasticity DMS110 manufactured by Seiko Denshi Kogyo KK was used. The measurement conditions were as follows: measurement temperature: -100 to 200 ° C., measurement frequency:
At 10 Hz, the heating rate was 2 ° C./min. The polytetrafluoroethylene mixed powder is heated at a mold temperature of 160 ° C.
A sample piece heat-molded under the conditions of MPa was measured.

(2) Melt tension The pellets of the resin composition were used with a drop-type flow tester, Capillograph, manufactured by Toyo Seiki. The measurement conditions were as follows: piston descending speed: 20 mm / min, die L / D: 10 m
m / φ2mm, Strand take-off speed: 1m / min
The melt tension was measured.

(3) Melt flow rate Using pellets of the resin composition, ASTM D123
According to No. 8, the measurement was performed at 230 ° C. and 2.16 kg.

(4) Dispersibility in thermoplastic resin 95 parts of the thermoplastic resin powder and 5 parts of the mixed powder containing polytetrafluoroethylene were hand-blended, and then a parallel plate type dynamic viscoelasticity measuring apparatus was used. After heating and melting, shear is applied to disperse the polytetrafluoroethylene-containing mixed powder in the thermoplastic resin, and the dispersion state of the polytetrafluoroethylene-containing mixed powder in the thermoplastic resin is evaluated by a cloud value. did. The parallel plate type dynamic viscoelasticity measuring device uses RDA-700 manufactured by Rheometric Scientific FEI Co., Ltd., temperature: 200 ° C., frequency: 10 rad / sec, strain: 600%, sample thickness: 1
A sample in which the polytetrafluoroethylene-containing mixed powder was dispersed in a thermoplastic resin under the conditions of mm, time: 5 and 30 minutes was cooled and collected. The haze was measured with a direct reading haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd.

(5) Weight-average particle diameter The particle dispersion was diluted with water and used as a sample liquid, which was measured by a dynamic light scattering method (ELS800 manufactured by Otsuka Electronics Co., Ltd., temperature 25 ° C., scattering angle 90 °). .

Example 1 As a polytetrafluoroethylene-based particle dispersion, Fluon AD936 manufactured by Asahi ICI Fluoropolymers Co., Ltd. having a weight average particle diameter of 290 nm was used. The solid concentration of AD936 is 63.0% by weight,
Contains 5% by weight of polyoxyethylene nonylphenyl ether based on polytetrafluoroethylene. 83.
116.7 parts of distilled water was added to 3 parts of AD936 to obtain a polytetrafluoroethylene particle dispersion (F-1).

In 70 parts of dodecyl methacrylate and 30 parts of methyl methacrylate, 0.1 part of azobisdimethylvaleronitrile was dissolved, and a mixed solution of 2.0 parts of sodium dodecylbenzenesulfonate and 300 parts of distilled water was added. After stirring at 10000 rpm for 2 minutes with a homomixer, the mixture was passed through a homogenizer twice at a pressure of 30 MPa to obtain a stable pre-dispersion liquid of lauryl methacrylate.
This was charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet, the internal temperature was raised to 80 ° C. under a nitrogen stream, and the mixture was stirred for 3 hours to perform radical polymerization. A dispersion (P-1) was obtained.

160 parts of F-1 and 119.0 parts of P-1
Was charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple and a nitrogen inlet, and 82.9 parts of distilled water was added thereto, followed by stirring at room temperature for 1 hour under a nitrogen stream. Thereafter, the temperature in the system was raised to 80 ° C., and a mixed solution of 0.001 part of iron (II) sulfate, 0.003 part of sodium ethylenediaminetetraacetate, 0.24 part of Rongalite salt, and 10 parts of distilled water was added. A mixture of 30 parts of methacrylate and 0.6 part of tertiary butyl peroxide was added dropwise over 1 hour, and after completion of the addition, the internal temperature was maintained at 80 ° C. for 1 hour to complete the radical polymerization. 1) was obtained.

TEM observation of the particle dispersion (L-1) confirmed that polytetrafluoroethylene particles having a particle diameter of about 300 nm had a morphology encapsulated by organic polymer particles.

400 parts of this particle dispersion (L-1) is poured into 800 parts of 70 ° C. hot water containing 10 parts of calcium chloride, the solid is separated, filtered and dried to obtain a mixed powder containing polytetrafluoroethylene. A body (M-1) was obtained.

The dried M-1 was shaped into a strip by press molding at 160 ° C., and dynamic viscoelasticity was measured. The result is shown in FIG. As a result, it was confirmed that the organic polymer particles had two distinct loss tangent peaks.

Comparative Example 1 Dodecyl methacrylate 50
0.1 part of azobisdimethylvaleronitrile was dissolved in 50 parts of methyl methacrylate and 50 parts of methyl methacrylate, and a mixed solution of 2.0 parts of sodium dodecylbenzenesulfonate and 300 parts of distilled water was added thereto.
And then passed through a homogenizer twice at a pressure of 30 MPa to obtain a stable lauryl methacrylate preliminary dispersion. This was charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet, the internal temperature was raised to 80 ° C. under a nitrogen stream, and the mixture was stirred for 3 hours to perform radical polymerization. A dispersion (P-2) was obtained.

160 parts of F-1 used in Example 1 and 11 parts
9.0 parts of P-2 and stirring blade, condenser, thermocouple,
The mixture was charged into a separable flask equipped with a nitrogen inlet, 82.9 parts of distilled water was added, and the mixture was stirred at room temperature for 1 hour under a nitrogen stream. Thereafter, the temperature inside the system was raised to 80 ° C., and iron (II) sulfate 0.1.
001 parts, sodium ethylenediaminetetraacetate 0.00
After adding a mixture of 3 parts, 0.24 part of Rongalite salt and 10 parts of distilled water, a mixture of 30 parts of methyl methacrylate and 0.6 part of tertiary butyl peroxide was added dropwise over 1 hour. The internal temperature was maintained at 80 ° C. for 1 hour to complete the radical polymerization, and a particle dispersion was obtained.

400 parts of the particle dispersion is poured into 800 parts of 70 ° C. hot water containing 10 parts of calcium chloride, the solid is separated, filtered and dried to obtain a mixed powder containing polytetrafluoroethylene (M-2). ) Got.

The dried M-2 was shaped into a strip by press molding at 160 ° C., and dynamic viscoelasticity was measured. The result is shown in FIG. This confirmed that the organic polymer particles had only one clear loss tangent peak.

Example 2 Using 95 parts of powdery polypropylene (melt flow rate: 5.0 g / 10 minutes) and 5 parts of the polytetrafluoroethylene-containing mixed powder M-1 obtained in Example 1 were used. And the dispersibility was evaluated. Table 1 shows the results
Shown in

Comparative Example 2 Using 95 parts of powdery polypropylene (melt flow rate 5.0 g / 10 min) and 5 parts of the polytetrafluoroethylene-containing mixed powder M-2 obtained in Comparative Example 1 And the dispersibility was evaluated. Table 1 shows the results
Shown in M-1 having two loss tangent peaks is
It shows a low haze value and excellent dispersibility.

(Examples 3 and 4) As a thermoplastic resin, homopolypropylene pellets (melt flow rate 5.0
g / 10 min), and hand-blending this with the polytetrafluoroethylene-containing mixed powder M-1 obtained in Example 1 at the ratio shown in Table 2, and then using a twin-screw extruder (WE
RNER &PFLEIDERER's ZSK30), barrel temperature 200 ° C, screw rotation speed 200r
The mixture was melt-kneaded at pm and formed into pellets. Table 2 shows the results of measuring various physical properties using the obtained pellets.

Comparative Examples 3 and 4 Homopolypropylene pellets (melt flow rate 5.0) were used as thermoplastic resins.
g / 10 minutes), and after hand-blending the mixture and the polytetrafluoroethylene-containing mixed powder M-2 obtained in Comparative Example 1 at a ratio shown in Table 2, a twin-screw extruder (WE
RNER &PFLEIDERER's ZSK30), barrel temperature 200 ° C, screw rotation speed 200r
The mixture was melt-kneaded at pm and formed into pellets. Table 2 shows the results of measuring various physical properties using the obtained pellets.

(Comparative Examples 5 to 7) For comparison, a polyolefin alone was extruded into pellets under the same conditions as in Example 3 (Comparative Example 5), and powdered polyolefin was mixed with powdered polytetrafluoroethylene. After mixing and stirring at a high speed at room temperature with a Henschel mixer, mixing and simultaneously applying a shearing force to fibrillate polytetrafluoroethylene, extruded and pelletized under the same conditions as in Example 3 (Comparative Examples 6 to 7). Was evaluated in the same manner as in Example 3. Table 2 shows the results.

As the polyolefin, homopolypropylene pellets (Comparative Example 5) or powdered polypropylene (Comparative Examples 6 to 7) (both having a melt flow rate of 5.0 g / 10 minutes) were used. Used Fluon CD123 manufactured by Asahi ICI Fluoropolymers. CD123 has a particle size of 0.2
Polytetrafluoroethylene primary particles of about 0.3 μm are aggregated to form an aggregate of several hundred μm.

From Tables 1 and 2, the polytetrafluoroethylene-containing mixed powder M-2 having two loss tangent peaks obtained in Example 1 has only one loss tangent peak obtained in Comparative Example 1. As compared with the polytetrafluoroethylene-containing mixed powder M-2, when added to a thermoplastic resin,
The improvement of the moldability of the thermoplastic resin was equivalent, but it was found that the dispersibility of polytetrafluoroethylene in the thermoplastic resin was good. Furthermore, as compared with Comparative Examples 6 to 10, the value of the melt tension is remarkably large, and has good moldability.

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

The polytetrafluoroethylene-containing mixed powder of the present invention has an extremely good dispersibility in a thermoplastic resin, and the thermoplastic resin composition containing the mixed powder has a high melting tension and a calendering property. It has excellent moldability such as take-up property during processing, thermoformability, blow moldability, and foam moldability. Further, when the composition of the present invention is used, extrudability of a sheet, a film and the like is good.

[Brief description of the drawings]

FIG. 1 is a graph showing the temperature dependence of the loss tangent (tan δ) of Example 1 and Comparative Example 1.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 27:18)

Claims (5)

[Claims] 1. A polytetrafluoroethylene-containing mixed powder comprising polytetrafluoroethylene particles (A) having a particle diameter of 10 μm or less and organic polymer particles (B), and the mixed powder A polytetrafluoroethylene-containing mixed powder, which has substantially two or more loss tangent (tan δ) peaks of the organic polymer particles (B) in dynamic viscoelasticity measurement. 2. A thermoplastic resin composition obtained by blending the polytetrafluoroethylene-containing mixed powder according to claim 1 with a thermoplastic resin (C). 3. A foam comprising the thermoplastic resin composition according to claim 2. 4. A thermoformed sheet comprising the thermoplastic resin composition according to claim 2. 5. A fiber comprising the thermoplastic resin composition according to claim 2.