JP2006063176A - Polytetrafluoroethylene-containing powder composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PTFE (polytetrafluoroethylene)-containing powder composition without causing a blocking phenomenon, a bridging phenomenon and a clogging phenomenon in a transport line even when the content of the PTFE is increased and to provide a method for producing the composition. <P>SOLUTION: The PTFE-containing powder composition contains particles of a polymer (A) composed of 40-90 mass% of the PTFE and 60-10 mass% of an organic polymer and particle of an organic polymer (B) having 80-170°C glass transition temperature in an amount of 0.1-10 pts. mass based on 100 pts. mass of the particles of the polymer (A). The particles of the organic polymer (B) stick to the surfaces of the particles of the polymer (A). The method for producing the PTFE-containing powder composition comprises adding a latex containing 0.1-10 pts. mass of the organic polymer (B) to a slurry prepared by coagulating a latex containing 100 pts. mass of the polymer (A) and passing the resultant mixture through a dehydrating and a drying steps. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polytetrafluoroethylene-containing powder composition and a method for producing the same.

  In recent years, with the automation of powder measurement and the increase in the size of the transportation system, labor saving in the process of handling powder has been promoted, and the problem of handling the powder itself has been highlighted. That is, blocking resistance, fluidity and bulk specific gravity against troubles such as blocking phenomenon that powders solidify during storage, bridging phenomenon that powders stop in hopper, clogging of transportation line due to insufficient fluidity, etc. There is a strong demand for improvement in powder characteristics represented by

  Polytetrafluoroethylene used as a modifier for preventing dripping of a thermoplastic resin or the like has a fibril forming ability, so that a blocking phenomenon and a bridging phenomenon are likely to occur. Various methods for improving the powder characteristics have been studied so far.

  For example, there is a method of completely or partially encapsulating polytetrafluoroethylene by polymerizing monomers in the presence of polytetrafluoroethylene (Patent Document 1). However, in this method, the larger the polytetrafluoroethylene content, the larger the particle size of the obtained powder and the lower the fluidity of the powder. That is, in this method, the handleability tends to decrease as the polytetrafluoroethylene content increases.

  Also, there is a method of forming a powdery polymer mixture by mixing and coagulating an organic thermoplastic polymer and polytetrafluoroethylene latex (Patent Document 2). However, in this method, the polytetrafluoroethylene content increases and the polytetrafluoroethylene tends to appear on the surface layer, and the handleability tends to decrease as the polytetrafluoroethylene content increases.

  Furthermore, the polytetrafluoroethylene containing modifier using the (meth) acrylic-acid alkylester type polymer which contains 70 mass% or more of structural units which consist of a (meth) acrylic-acid alkylester which has a C1-C4 alkyl group is provided. Patent Document 3 discloses this. Although this document discloses a polytetrafluoroethylene content up to 70% by mass, as the polytetrafluoroethylene content increases, the powder flowability and storage stability tend to decrease. It is not easy to reproduce the example.

As products using these technologies, “Metabrene A3800 (manufactured by Mitsubishi Rayon Co., Ltd.)” and “Blendex 449 (manufactured by Crompton)” are commercially available. However, the content of polytetrafluoroethylene contained in these is about 50% by mass, and there has been a demand for a resin additive having higher polytetrafluoroethylene content and good powder characteristics and dispersibility.
Japanese Patent No. 3469391 JP 60-258263 A International Publication No. 02/090440 Pamphlet

  Therefore, even if the polytetrafluoroethylene content is increased, the object of the present invention is that there is no blocking phenomenon, bridging phenomenon, clogging phenomenon in the transportation line, etc. It is an object of the present invention to provide a polytetrafluoroethylene-containing powder composition capable of saving labor and the like and a method for producing the same.

  As a result of intensive studies in view of the present situation, the present inventors have determined that a part or all of the surface of the polymer (A) particles composed of polytetrafluoroethylene and an organic polymer is subjected to organic weight having a glass transition temperature of 80 to 170 ° C. It discovered that the said subject was solved by coat | covering with a unification | combination (B), and reached | attained this invention.

  That is, the polytetrafluoroethylene-containing powder composition of the present invention comprises polymer (A) particles composed of 40 to 90% by mass of polytetrafluoroethylene and 60 to 10% by mass of an organic polymer, and the polymer (A) particles 100. It contains 0.1 to 10 parts by mass of organic polymer (B) particles having a glass transition temperature of 80 to 170 ° C. with respect to parts by mass, and at least a part of the organic polymer (B) particles are polymer (A) particles. It adheres to the surface of this.

  Moreover, the manufacturing method of the polytetrafluoroethylene containing powder composition of this invention is latex containing 100 mass parts of polymers (A) which consist of 40-90 mass% of polytetrafluoroethylene and 60-10 mass% of organic polymers. After adding a latex containing 0.1 to 10 parts by mass of the organic polymer (B) to the slurry obtained by coagulation, through a dehydration and drying step, at least a part of the organic polymer (B) particles are polymer ( A) A powder composition adhered to the surface of the particles is obtained.

  The polytetrafluoroethylene-containing powder composition of the present invention has no blocking phenomenon, bridging phenomenon, clogging phenomenon in the transportation line, etc. even if the polytetrafluoroethylene content is increased, and as a result, automatic powder measurement This makes it possible to save labor, such as increasing the size of the transportation system. Moreover, according to the manufacturing method of the polytetrafluoroethylene containing powder composition of this invention, such a polytetrafluoroethylene containing powder composition can be obtained easily.

<Polymer (A)>
The polymer (A) in the present invention (hereinafter also referred to as the component (A)) is polytetrafluoroethylene 40 to 90% by mass, preferably 60 to 80% by mass, and organic polymer 60 to 10% by mass, preferably 40 It consists of ˜20% by mass [total 100% by mass of polytetrafluoroethylene and organic polymer].
When the content of polytetrafluoroethylene in the component (A) is small, the component (A) itself often has sufficient powder characteristics by known techniques, and the composition of the powder composition of the present invention do not have to. On the other hand, if it exceeds 90% by mass, it is difficult to obtain a powder composition having sufficient powder characteristics even when an organic polymer (B) described later is added.

(Polytetrafluoroethylene)
The polytetrafluoroethylene in the present invention is obtained by homopolymerizing a tetrafluoroethylene monomer or copolymerizing a tetrafluoroethylene monomer and a copolymer component. As a copolymerization component, a fluorine-containing olefin such as hexafluoropropylene, chlorotrifluoroethylene, fluoroalkylethylene, and perfluoroalkyl vinyl ether; a perfluoroalkyl (meth) acrylate, etc. as long as the properties of polytetrafluoroethylene are not impaired. Fluorine-containing alkyl (meth) acrylate and the like can be used. The content of the copolymer component is preferably 10% by mass or less with respect to tetrafluoroethylene. Polytetrafluoroethylene is available as an aqueous dispersion, and as such an aqueous dispersion, Asahi Glass Fluoropolymers' full-on AD-1, AD-936, Daikin Industries, Ltd. polyflon D-1, D -2, Teflon (registered trademark) 30J manufactured by Mitsui DuPont Fluorochemical Co., Ltd. can be given as a representative example.

(Organic polymer)
The organic polymer in the present invention includes a polymer obtained by polymerizing a vinyl monomer and a polymer obtained by polycondensation.
Examples of vinyl monomers include aromatic vinyl compounds, vinyl cyanide compounds, (meth) acrylic acid esters, and other copolymerizable monomers.

  Examples of the aromatic vinyl compound include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethylstyrene, N, N-diethyl-p-aminoethylstyrene, vinylpyridine, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, fluorostyrene, ethylstyrene, vinylnaphthalene and the like can be mentioned. These are used alone or in combination of two or more. As the aromatic vinyl compound, styrene and α-methylstyrene are particularly preferable.

  Examples of the cyanated vinyl compound include acrylonitrile and methacrylonitrile. These are used alone or in combination of two or more. As the vinyl cyanide compound, acrylonitrile is particularly preferable.

  Examples of (meth) acrylic acid esters include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, dodecyl acrylate, octadecyl acrylate, phenyl acrylate, and benzyl. Acrylic esters such as acrylates; methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, phenyl methacrylate, Methacrylic acid esters such as emissions Jill methacrylate. These are used alone or in combination of two or more. As the (meth) acrylic acid ester, methyl methacrylate is particularly preferable.

Examples of other copolymerizable monomers include unsaturated acid anhydrides such as maleic anhydride, itaconic anhydride and citraconic anhydride; unsaturated acids such as acrylic acid and methacrylic acid; maleimide and N-methylmaleimide , N-butylmaleimide, N- (p-methylphenyl) maleimide, N-phenylmaleimide, N-cyclohexylmaleimide and other maleimide compounds; glycidyl methacrylate and other epoxy compounds. The maleimide compound includes, for example, a copolymer obtained by copolymerizing maleic anhydride and imidizing it with aniline or the like.
The above vinyl monomers can be used singly or in combination of two or more.

(Production of polymer (A))
The polymer (A) is obtained by polymerizing a vinyl monomer constituting an organic polymer in the presence of polytetrafluoroethylene, or by mixing a polytetrafluoroethylene latex and an organic polymer latex. It is done. The method of polymerizing the vinyl monomer in the presence of polytetrafluoroethylene is preferably emulsion polymerization. In the method of mixing the latex of polytetrafluoroethylene and the latex of the organic polymer, as a method for obtaining the latex of the organic polymer, a method by emulsion polymerization or a polymer obtained by solution polymerization or bulk polymerization is known. The method of emulsifying by a method is used.

Specifically, the emulsion polymerization of a vinyl monomer is usually heated to 5 to 98 ° C. while stirring a vinyl monomer added with a polymerization initiator, a chain transfer agent, an emulsifier and the like. Done.
As a polymerization initiator, redox is a combination of organic hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, and reducing agents such as sugar-containing pyrophosphate prescription and sulfoxylate prescription. System polymerization initiators or peroxides such as persulfate, azobisisobutyronitrile, benzoyl peroxide are used.

  Chain transfer agents include mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-stearyl mercaptan; chloroform, bromoform, carbon tetrachloride, tetraodor Hydrocarbons such as carbonized carbon; xanthogens such as dimethylxanthogen disulfide and diisopropylxanthogen disulfide; α-methylstyrene dimer, 9,10-dihydroanthracene, 1,4-cyclohexadiene, 1,4-hexadiene, 2, 5-dihydrofuran etc. are mentioned.

As the emulsifier, commonly used emulsifiers can be used. Sodium or potassium salts of fatty acids such as rosin acid, oleic acid, lauric acid, stearic acid, alkenyl succinic acid, alkylallyl sulfonates such as sodium dodecylbenzene sulfonate, Anionic surfactants such as dialkylsulfosuccinic acid are preferred. From the viewpoint of coagulation properties, fatty acid salts are particularly preferred.
As the emulsion polymerization method, generally known emulsion polymerization methods such as batch addition polymerization of monomers, continuous addition polymerization of monomers, and multistage polymerization can be employed. Can be added.

<Organic polymer (B)>
The organic polymer (B) in the present invention (hereinafter also referred to as the component (B)) is a polymer obtained by polymerizing a vinyl monomer, a polymer obtained by polycondensation, or the like. As a vinyl-type monomer, the thing similar to the vinyl-type monomer which comprises a polymer (A) can be used.

The glass transition temperature of the organic polymer (B) is 80 to 170 ° C, preferably 90 to 120 ° C. If the glass transition temperature of the organic polymer (B) is too low, sufficient powder properties cannot be obtained. On the other hand, if the glass transition temperature of the organic polymer (B) exceeds 170 ° C., solidification becomes difficult and ultrafine powder is obtained. May occur in large quantities, or coagulation may be insufficient. The glass transition temperature of the organic polymer (B) can be easily adjusted by appropriately selecting the type and amount of the vinyl monomer used.
Here, the glass transition temperature of the organic polymer (B) can be measured by, for example, a DSC measuring apparatus (Seiko Electronics Co., Ltd., DSC6200, etc.).

  The mass average molecular weight of the organic polymer (B) is preferably 1,000,000 or less, more preferably 3 to 900,000. If the mass average molecular weight of the organic polymer (B) exceeds 1,000,000, it is not preferable because when a thermoplastic resin composition containing the obtained powder composition is molded, fish eyes may be formed in the molded product. . The adjustment of the mass average molecular weight can be easily achieved by adjusting the amount of chain transfer agent or polymerization initiator. Here, the mass average molecular weight is, for example, converted to PMMA using a column (manufactured by Showa Denko KK, K-806L) in gel permeation chromatography (manufactured by Shimadzu Corporation, LC-10A system). This is the value obtained in.

  Examples of the method for producing the organic polymer (B) include an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, and a method of emulsifying a polymer obtained by solution polymerization or bulk polymerization by a known method. . Among these, a method of polymerizing a vinyl monomer by an emulsion polymerization method is preferable. The emulsion polymerization method for producing the component (B) is the same as the emulsion polymerization method for preparing the component (A).

<Polytetrafluoroethylene-containing powder composition>
The polytetrafluoroethylene-containing powder composition of the present invention contains polymer (A) particles and organic polymer (B) particles, and part or all of the organic polymer (B) particles are polymer (A) particles. It is attached to the surface.

  Content of an organic polymer (B) is 0.1-10 mass parts with respect to 100 mass parts of (A) component, Preferably it is 1-7 mass parts, More preferably, it is 2-5 mass parts. is there. If the content of the organic polymer (B) is too small, sufficient powder characteristics cannot be obtained, and if the content of the organic polymer (B) is too large, the mechanical properties are deteriorated.

  The mass average particle diameter of the polymer (A) particles is preferably 50 to 1000 μm, more preferably 100 to 800 μm, and particularly preferably 200 to 600 μm. When the mass average particle diameter of the polymer (A) particles is in the above range, a powder composition having much more excellent powder characteristics can be obtained. Here, the mass average particle size is a value obtained by shaking 20 g of powder for 5 minutes to classify and obtaining the average particle size by a standard sieve.

  The mass average particle diameter of the organic polymer (B) particles is preferably 30 to 1000 nm, more preferably 50 to 800 nm, and particularly preferably 80 to 500 nm. When the mass average particle diameter of the organic polymer (B) particles is too small, it is not preferable because a large amount of an emulsifier is required, and when it is too large, it is not preferable because it is difficult to coat the polymer (A) particles. .

<Method for Producing Polytetrafluoroethylene-Containing Powder Composition>
Although the manufacturing method of the polytetrafluoroethylene containing powder composition of this invention is not specifically limited, For example, it can manufacture easily by any one method of following (i)-(iii).

(I) Addition and mixing of 0.1 to 10 parts by mass (solid content conversion) latex of organic polymer (B) to slurry obtained by coagulating 100 parts by mass (solid content conversion) latex of polymer (A) Then, a method of obtaining a powder composition through dehydration and drying steps.
(Ii) 0.1 to 10 parts by mass (in terms of solid content) of the organic polymer (B) can be coagulated in a slurry obtained by coagulating 100 parts by mass (in terms of solid content) of latex of the polymer (A). The slurry obtained and / or the powder after drying of the slurry is added and mixed, and then a dehydration and drying process is performed to obtain a powder composition.
(iii) A method in which 0.1 to 10 parts by mass of the powder of the organic polymer (B) is added to and mixed with 100 parts by mass of the powder of the polymer (A) to obtain a powder composition.

Among these production methods, the preferred method is the method (i). According to this method, since the particle size of the component (B) is small, the powder composition that the component (B) covers the component (A) with a higher probability and the powder characteristics are more excellent.
As a coagulant for coagulating the latex of the polymer (A) and the latex of the organic polymer (B), inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid and nitric acid; organic acids such as acetic acid; so-called sodium and potassium Alkali metal halides; alkali metal salts with inorganic acids; alkali metal salts with organic acids and the like are used. These coagulants are used alone or in combination of two or more. These coagulants are used as an aqueous solution, and the addition amount is not particularly limited, but an amount capable of sufficiently coagulating the latex is used.

<Modifier>
The polytetrafluoroethylene-containing powder composition of the present invention can be used, for example, as an additive for thermoplastic resins, specifically as a modifier for preventing dripping of thermoplastic resins.

  In the polytetrafluoroethylene-containing powder composition of the present invention described above, the polymer (A) containing polytetrafluoroethylene contains a specific amount of an organic polymer, and the polymer (A) By attaching an organic polymer (B) having a glass transition temperature of 80 to 170 ° C. to the surface and coating part or all of the surface of the polymer (A) particles with the organic polymer (B), polytetrafluoro Ethylene becomes difficult to form fibrils, and powder characteristics are improved. As a result, there is no blocking phenomenon, bridging phenomenon, clogging phenomenon in the transportation line, etc. As a result, it is possible to save labor such as automation of powder measurement and enlargement of the transportation system.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
In the examples, parts and% are based on mass unless otherwise specified. Various measurements in the examples were based on the following methods.

(1) Mass average molecular weight measurement:
In gel permeation chromatography (manufactured by Shimadzu Corporation, LC-10A system), measurement was performed using a column (manufactured by Showa Denko KK, K-806L).
(2) Mass average particle size measurement:
The particle dispersion was diluted with distilled water and measured using a CHDF2000 particle size distribution meter manufactured by MATEC USA. The measurement conditions were standard conditions recommended by MATEC. That is, using a dedicated cartridge cartridge for particle separation and carrier liquid, the liquidity is almost neutral, the flow rate is 1.4 ml / min, the pressure is about 4000 psi (2600 KPa), and the temperature is kept at 35 ° C., the concentration is about 3%. A 0.1 ml diluted latex sample was used for the measurement. As the standard particle size substance, a total of 12 monodisperse polystyrenes having a known particle size manufactured by DUKE in the United States were used in the range of 0.02 μm to 0.8 μm.

(3) Measurement of powder fluidity:
The measurement was performed using a bulk specific gravity meter (manufactured by Tsutsui Rika Kikai Co., Ltd.) in accordance with JIS K6721. In this measurement, after filling the funnel of the bulk density meter with the powder, the powder was allowed to flow through the funnel for 10 seconds, the powder that flowed out was weighed, and an index of powder fluidity (g / 10 sec) did. The larger the amount of powder that flows out in 10 seconds, the better the flowability of the powder. In actual work, it means that a powder with good fluidity also has good handleability.

(4) Storage stability measurement of powder:
An acrylic resin container is filled with 20 g of powder, and a 5 kg weight is placed on the container, and the oven is placed in a gear oven (GHPS-222, manufactured by Tabai Co., Ltd.) at 50 ° C. 6 The mixture was left for a period of time and then taken out and cooled at room temperature to prepare a powder block. This powder block is placed on a sieve with a mesh of 12 mesh, and is crushed with a vibration sieve machine (Micro-type electromagnetic vibration sieve machine M-2, manufactured by Tsutsui Rika Kikai Co., Ltd.). The time at the point of time was defined as the storage stability of the powder. This means that the shorter the amount of time this crushed amount reaches 60%, the harder the powder will be when the powder is actually stored, and the easier it will be to break up the lump of the powder even when it is solidified. .

(5) Flame retardancy test:
A vertical combustion test was performed in accordance with the UL94 standard. A test piece having a thickness of 1.6 mm was used.
(6) Dispersibility:
The presence or absence of aggregates in the injection-molded test piece was visually observed and judged according to the following criteria.
(Double-circle): There is no aggregate in a test piece.
○: There is an aggregate of 0.5 mm or less in the specimen.
X: There exists an aggregate of 0.5 mm or more in the specimen.

[Preparation of Organic Polymer (B-1) Latex]
290 parts of distilled water, 1.0 part of dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”) as an emulsifier, 98 parts of methyl methacrylate, 2 parts of ethyl acrylate, 0.003 part of n-octanethiol, stirring blade , Charged to a separable flask equipped with a condenser, thermocouple, and nitrogen inlet, and heated to 60 ° C. under a nitrogen stream. Subsequently, what melt | dissolved 0.2 part of potassium persulfate in 10 parts of distilled water was added, and radical polymerization was started. After the heat generation was completed, the temperature in the system was maintained at 60 ° C. for 1 hour to obtain an organic polymer (B-1) latex. The latex had a solid content concentration of 26%, the organic polymer (B-1) had a mass average particle size of 100 nm, and a mass average molecular weight of 800,000. The glass transition temperature of the organic polymer (B-1) measured by DSC is 101 ° C.

[Example 1: Preparation of powder composition (X-1)]
145 parts of distilled water, 1.0 part of dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”) as an emulsifier, 40 parts of methyl methacrylate, 10 parts of butyl acrylate, stirring blade, condenser, thermocouple, nitrogen inlet The mixture was charged into a separable flask equipped with a temperature of 60 ° C. under a nitrogen stream. Next, a solution obtained by dissolving 0.1 part of potassium persulfate in 5 parts of distilled water was added to initiate radical polymerization. After the heat generation was completed, the temperature in the system was maintained at 60 ° C. for 1 hour to obtain an organic polymer latex.
This latex contains a polytetrafluoroethylene (hereinafter abbreviated as PTFE) particle dispersion "Fluon XAD938" manufactured by Asahi Fluoropolymers Co., Ltd. (solid content concentration 63.0%, PTFE containing 5% surfactant) ) 83.3 parts (50 parts as PTFE) and 16.7 parts of distilled water were added to obtain a polymer (A-1) latex.

400 parts of 1% calcium acetate aqueous solution is heated and stirred at 80 ° C., and while maintaining the temperature, 300 parts of the polymer (A-1) latex (100 parts as a polymer component) is gradually added dropwise to solidify and precipitate the solid. It was. Furthermore, 8 parts of organic polymer (B-1) latex (2 parts as a polymer component) was added to the slurry, and stirring was continued for 5 minutes. Then, the temperature of the slurry was raised to 95 ° C. and solidified.
Finally, this precipitate was separated, filtered and dried to obtain a powder composition (X-1) of the present invention.

[Example 2: Preparation of powder composition (X-2)]
85 parts of distilled water, 0.6 parts of dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”) as an emulsifier, 24 parts of methyl methacrylate, 6 parts of butyl acrylate, stirring blade, condenser, thermocouple, nitrogen inlet The mixture was charged into a separable flask equipped with a temperature of 60 ° C. under a nitrogen stream. Subsequently, what dissolved 0.06 part of potassium persulfate in 5 parts of distilled water was added, and radical polymerization was started. After the heat generation was completed, the temperature in the system was maintained at 60 ° C. for 1 hour to obtain an organic polymer latex.
To this latex, 116.7 parts (70% PTFE content) of PTFE particle dispersion "Fluon XAD938" manufactured by Asahi Fluoropolymers Co., Ltd. (containing 63.0% solid content and 5% surfactant with respect to PTFE). Part) and 63.3 parts of distilled water were added to obtain a polymer (A-2) latex.

400 parts of 1% calcium acetate aqueous solution is heated and stirred at 80 ° C., and while maintaining the temperature, 300 parts of the polymer (A-2) latex (100 parts as the polymer) is gradually added dropwise to solidify and precipitate the solid matter. It was. Furthermore, 8 parts of organic polymer (B-1) latex (2 parts as a polymer component) was added to the slurry, and stirring was continued for 5 minutes. Then, the temperature of the slurry was raised to 95 ° C. and solidified.
Finally, this precipitate was separated, filtered and dried to obtain a powder composition (X-2) of the present invention.

[Example 3: Preparation of powder composition (X-3)]
Distilled water 55 parts, emulsifier dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”) 0.4 part, methyl methacrylate 16 parts, butyl acrylate 4 parts, stirring blade, condenser, thermocouple, nitrogen inlet The mixture was charged into a separable flask equipped with a temperature of 60 ° C. under a nitrogen stream. Subsequently, what dissolved 0.04 part of potassium persulfate in 5 parts of distilled water was added, and radical polymerization was started. After the heat generation was completed, the temperature in the system was maintained at 60 ° C. for 1 hour to obtain an organic polymer latex.
To this latex, 133.3 parts of PTFE particle dispersion “Fluon XAD938” manufactured by Asahi Fluoropolymers Co., Ltd. (containing 63.0% solid content and 5% surfactant with respect to PTFE) (80% PTFE content) Part) and 86.7 parts of distilled water were added to obtain a polymer (A-3) latex.

400 parts of 1% calcium acetate aqueous solution is heated and stirred at 80 ° C., and while maintaining the temperature, 300 parts of the polymer (A-3) latex (100 parts as the polymer) is gradually added dropwise to solidify and precipitate the solid. It was. Furthermore, 8 parts of organic polymer (B-1) latex (2 parts as a polymer component) was added to the slurry, and stirring was continued for 5 minutes. Then, the temperature of the slurry was raised to 95 ° C. and solidified.
Finally, this precipitate was separated, filtered and dried to obtain a powder composition (X-3) of the present invention.

[Example 4: Preparation of powder composition (X-4)]
PTFE particle dispersion "Fluon XAD938" manufactured by Asahi Fluoropolymers Co., Ltd. (solid content concentration 63.0%, containing 5% surfactant with respect to PTFE) 83.3 parts (50 parts as PTFE content), distillation 161.7 parts of water, 1.0 part of dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”) as an emulsifier, 40 parts of methyl methacrylate, 10 parts of butyl acrylate, stirring blade, condenser, thermocouple, nitrogen introduction The mixture was placed in a separable flask equipped with a mouth and heated to 60 ° C. under a nitrogen stream. Next, a solution obtained by dissolving 0.1 part of potassium persulfate in 5 parts of distilled water was added to initiate radical polymerization. After the heat generation was completed, the temperature in the system was maintained at 60 ° C. for 1 hour to obtain a polymer (A-4) latex.

400 parts of 1% calcium acetate aqueous solution is heated and stirred at 80 ° C., and while maintaining the temperature, 300 parts of the polymer (A-4) latex (100 parts as the polymer) is gradually added dropwise to solidify and precipitate the solid. It was. Furthermore, 8 parts of organic polymer (B-1) latex (2 parts as a polymer component) was added to the slurry, and stirring was continued for 5 minutes. Then, the temperature of the slurry was raised to 95 ° C. and solidified.
Finally, this precipitate was separated, filtered and dried to obtain a powder composition (X-4) of the present invention.

[Example 5: Preparation of powder composition (X-5)]
PTFE particle dispersion "Fluon XAD938" manufactured by Asahi Fluoropolymers Co., Ltd. (solid content concentration 63.0%, containing 5% surfactant with respect to PTFE) 83.3 parts (50 parts as PTFE content), distillation 161.7 parts of water, 1.0 part of dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”) as an emulsifier, 40 parts of styrene, 10 parts of acrylonitrile, stirring blade, condenser, thermocouple, nitrogen inlet The prepared separable flask was charged and heated to 60 ° C. under a nitrogen stream. Next, a solution obtained by dissolving 0.1 part of potassium persulfate in 5 parts of distilled water was added to initiate radical polymerization. After the heat generation was completed, the temperature in the system was maintained at 60 ° C. for 1 hour to obtain a polymer (A-5) latex.

400 parts of a 1% calcium acetate aqueous solution is heated and stirred at 80 ° C., and while maintaining the temperature, 300 parts of polymer (A-5) latex (100 parts as a polymer) is gradually added dropwise to solidify and precipitate the solid matter. It was. Furthermore, 8 parts of organic polymer (B-1) latex (2 parts as a polymer component) was added to the slurry, and stirring was continued for 5 minutes. Then, the temperature of the slurry was raised to 95 ° C. and solidified.
Finally, this precipitate was separated, filtered and dried to obtain a powder composition (X-5) of the present invention.

[Example 6: Preparation of powder composition (X-6)]
A mixture of 140 parts of distilled water, 1.0 part of dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”), 30 parts of 2-ethylhexyl acrylate, and 10 parts of methyl methacrylate as an emulsifier was mixed with a homomixer. Pre-dispersion was performed by stirring at 000 rpm for 5 minutes. Then, this dispersion was performed by passing twice through a homogenizer at a pressure of 20 MPa. This was charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet, and heated to 60 ° C. under a nitrogen stream. Next, 0.4 part of cumene hydroperoxide was added, and a mixed solution of 0.0005 part of iron (II) sulfate, 0.0015 part of disodium ethylenediaminetetraacetate, 0.12 part of Rongalite salt and 5 parts of distilled water was then added. The radical polymerization was started. After the end of heat generation, the temperature inside the system was kept at 60 ° C. for 1 hour.

Thereafter, the temperature inside the system was raised to 80 ° C., and a mixed solution of 0.0005 part of iron (II) sulfate, 0.0015 part of disodium ethylenediaminetetraacetate, 0.12 part of Rongalite salt and 5 parts of distilled water was added. While maintaining the same temperature, a mixed solution of 8 parts of methyl methacrylate, 2 parts of butyl acrylate and 0.1 part of tertiary butyl hydroperoxide was added dropwise over 30 minutes to carry out the second stage polymerization. After the heat generation was completed, the temperature in the system was maintained at 80 ° C. for 1 hour to obtain an organic polymer latex.
To this organic polymer latex, 83.3 parts of PTFE particle dispersion "Fluon XAD938" (solid content concentration 63.0%, containing 5% surfactant with respect to PTFE) manufactured by Asahi Fluoropolymers Co., Ltd. and distilled 116.7 parts of water was added to obtain 400 parts of polymer (A-6) latex.

400 parts of 1% calcium acetate aqueous solution is heated and stirred at 80 ° C., and while maintaining the temperature, 400 parts of polymer (A-6) latex (100 parts as a polymer) is gradually added dropwise to solidify and precipitate the solid matter. It was. Furthermore, 8 parts of organic polymer (B-1) latex (2 parts as a polymer component) was added to the slurry, and stirring was continued for 5 minutes. Then, the temperature of the slurry was raised to 95 ° C. and solidified.
Finally, this precipitate was separated, filtered and dried to obtain a powder composition (X-6) of the present invention.

[Example 7: Preparation of powder composition (X-7)]
The powder of the present invention was prepared in the same manner as in Example 2 (powder composition (X-2)) except that the amount of the organic polymer (B-1) latex was 20 parts (5 parts as the polymer content). A body composition (X-7) was obtained.

[Preparation of organic polymer (B-2) latex]
390 parts of distilled water, 98 parts of methyl methacrylate, and 2 parts of ethyl acrylate were charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet, and the temperature was raised to 70 ° C. under a nitrogen stream. Then, 1 part of 2,2′-azobis (2-methylpropionamidine) dihydrochloride (manufactured by Wako Pure Chemical Industries, V-50) dissolved in 10 parts of distilled water was added to initiate radical polymerization. After the heat generation was completed, the temperature in the system was maintained at 70 ° C. for 1 hour to obtain an organic polymer (B-2) latex. The latex had a solid content concentration of 20%, the organic polymer (B-2) had a mass average particle diameter of 300 nm, and a mass average molecular weight of 300,000. Moreover, the glass transition temperature of the organic polymer (B-2) calculated by the formula of Fox is 101 degreeC.

[Example 8: Preparation of modifier (X-8)]
Except for using the organic polymer (B-2) latex instead of the organic polymer (B-1) latex (B-1), the same procedure as in Example 2 (powder composition (X-2)) was performed. A powder composition (X-8) of the present invention was obtained.

[Preparation of organic polymer (B-3) latex]
290 parts of distilled water, 1.0 part of dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”), 0.0005 part of iron (II) sulfate, 0.0015 part of disodium ethylenediaminetetraacetate, Rongalite salt 0.12 part was charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet, and heated to 60 ° C. under a nitrogen stream. Then, a mixture of 80 parts of styrene, 20 parts of acrylonitrile, and 0.4 parts of cumene hydroperoxide was slowly added dropwise over 2 hours to perform radical polymerization. After the heat generation was completed, the temperature in the system was maintained at 60 ° C. for 1 hour to obtain an organic polymer (B-3) latex. The latex had a solid content concentration of 26%, the organic polymer (B-3) had a mass average particle diameter of 100 nm, and a mass average molecular weight of 800,000. Moreover, the glass transition temperature of the organic polymer (B-3) measured by DSC is 100 ° C.

[Example 9: Preparation of powder composition (X-9)]
90 parts of distilled water, 0.6 parts of dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”), 0.0005 parts of iron (II) sulfate, 0.0015 parts of disodium ethylenediaminetetraacetate, Rongalite salt 0.12 part was charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet, and heated to 60 ° C. under a nitrogen stream. Next, a mixture of 19.2 parts of styrene, 4.8 parts of acrylonitrile, 6 parts of butyl acrylate, and 0.4 parts of cumene hydroperoxide was dropped over 2 hours to perform radical polymerization. After the heat generation was completed, the temperature in the system was maintained at 60 ° C. for 1 hour to obtain an organic polymer latex.
To this latex, 116.7 parts (70% PTFE content) of PTFE particle dispersion "Fluon XAD938" manufactured by Asahi Fluoropolymers Co., Ltd. (containing 63.0% solid content and 5% surfactant with respect to PTFE). Part) and 63.3 parts of distilled water were added to obtain a polymer (A-9) latex.

400 parts of 1% calcium acetate aqueous solution is heated and stirred at 80 ° C., and while maintaining the temperature, 300 parts of the polymer (A-9) latex (100 parts as the polymer) is gradually added dropwise to solidify and precipitate the solids. It was. Furthermore, 8 parts of organic polymer (B-3) latex (2 parts as a polymer component) was added to the slurry, and stirring was continued for 5 minutes. Then, the temperature of the slurry was raised to 95 ° C. and solidified.
Finally, the precipitate was separated, filtered and dried to obtain a powder composition (X-9) of the present invention.

[Preparation of organic polymer (B-4) latex]
An organic polymer (B-4) latex was obtained in the same manner as in the preparation of the organic polymer (B-3) latex, except that 80 parts of styrene and 20 parts of acrylonitrile were changed to 100 parts of styrene. The latex had a solid content concentration of 26%, the organic polymer (B-4) had a mass average particle diameter of 100 nm, and a mass average molecular weight of 800,000. Moreover, the glass transition temperature of the organic polymer (B-4) measured by DSC is 100 ° C.

[Example 10: Preparation of powder composition (X-10)]
90 parts of distilled water, 0.6 parts of dipotassium alkenyl succinate (manufactured by Kao Corporation, “Latemul ASK”), 0.0005 parts of iron (II) sulfate, 0.0015 parts of disodium ethylenediaminetetraacetate, Rongalite salt 0.12 part was charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet, and heated to 60 ° C. under a nitrogen stream. Next, a mixture of 24 parts of styrene, 6 parts of butyl acrylate and 0.4 part of cumene hydroperoxide was dropped over 2 hours to perform radical polymerization. After the heat generation was completed, the temperature in the system was maintained at 60 ° C. for 1 hour to obtain an organic polymer latex.
To this latex, 116.7 parts (70% PTFE content) of PTFE particle dispersion "Fluon XAD938" manufactured by Asahi Fluoropolymers Co., Ltd. (containing 63.0% solid content and 5% surfactant with respect to PTFE). Part) and 63.3 parts of distilled water were added to obtain a polymer (A-10) latex.

400 parts of a 1% calcium acetate aqueous solution is heated and stirred at 80 ° C., and while maintaining the temperature, 300 parts of polymer (A-10) latex (100 parts as a polymer) is gradually added dropwise to solidify and precipitate the solid. It was. Furthermore, 8 parts of organic polymer (B-4) latex (2 parts as a polymer content) was added to the slurry, and stirring was continued for 5 minutes. Then, the temperature of the slurry was raised to 95 ° C. and solidified.
Finally, this precipitate was separated, filtered and dried to obtain a powder composition (X-10) of the present invention.

[Preparation of Organic Polymer (B-5) Latex]
An organic polymer (B-5) latex was obtained in the same manner as in the preparation of the organic polymer (B-1) latex except that 80 parts of methyl methacrylate and 20 parts of ethyl acrylate were used. The latex had a solid content concentration of 26%, the organic polymer (B-5) had a mass average particle diameter of 100 nm, and a mass average molecular weight of 800,000. The glass transition temperature of the organic polymer (B-5) measured by DSC is 71 ° C.

[Comparative Example 1: Preparation of powder composition (Y-1)]
The same procedure as in Example 1 (powder composition (X-1)) was conducted except that the organic polymer (B-5) latex was used instead of the organic polymer (B-1) latex. Y-1) was obtained.

[Comparative Example 2: Preparation of powder composition (Y-2)]
The same procedure as in Example 2 (powder composition (X-2)) was conducted except that the organic polymer (B-5) latex was used instead of the organic polymer (B-1) latex, and the powder composition ( Y-2) was obtained.

[Comparative Example 3: Preparation of powder composition (Y-3)]
The same procedure as in Example 3 (powder composition (X-3)) was performed except that the organic polymer (B-5) latex was used instead of the organic polymer (B-1) latex, and the powder composition ( Y-3) was obtained.

[Comparative Example 4: Preparation of powder composition (Y-4)]
The same procedure as in Example 4 (powder composition (X-4)) was conducted except that the organic polymer (B-5) latex was used instead of the organic polymer (B-1) latex, and the powder composition ( Y-4) was obtained.

[Comparative Example 5: Preparation of powder composition (Y-5)]
The same procedure as in Example 5 (powder composition (X-5)) was conducted except that the organic polymer (B-5) latex was used instead of the organic polymer (B-1) latex, and the powder composition ( Y-5) was obtained.

[Comparative Example 6: Preparation of powder composition (Y-6)]
The same procedure as in Example 6 (powder composition (X-6)) was conducted except that the organic polymer (B-5) latex was used instead of the organic polymer (B-1) latex. Y-6) was obtained.

[Comparative Example 7: Preparation of powder composition (Y-7)]
The same procedure as in Example 7 (powder composition (X-7)) was conducted except that the organic polymer (B-5) latex was used instead of the organic polymer (B-1) latex. Y-7) was obtained.

[Comparative Example 8: Preparation of powder composition (Y-8)]
Except not using an organic polymer (B-1) latex, it carried out similarly to Example 2 (powder composition (X-2)), and obtained the powder composition (Y-8).

[Comparative Example 9: Preparation of powder composition (Y-9)]
Except not using an organic polymer (B-3) latex, it carried out similarly to Example 9 (powder composition (X-9)), and obtained the powder composition (Y-9).

[Comparative Example 10: Preparation of powder composition (Y-10)]
Except not using an organic polymer (B-4) latex, it carried out similarly to Example 10 (powder composition (X-10)), and obtained the powder composition (Y-10).

[Comparative Example 11: PTFE powder]
As PTFE (100%) powder, Asahi Glass Co., Ltd. product name: Aflon PTFE CD-1 was used.

About the powder composition of Examples 1-10 and Comparative Examples 1-11, fluidity | liquidity and storage stability were evaluated. The results are shown in Table 1.
As is apparent from Table 1, the powder composition of the present invention has better powder properties than the comparative example.

[Examples 11 to 28, Comparative Examples 12 to 31: Evaluation as a modifier (I)]
The powder compositions (X-1) to (X-10), the powder compositions (Y-1) to (Y-10), and the PTFE (100%) powder are used as thermoplastic resin modifiers. The flame retardancy of the obtained thermoplastic resin composition was evaluated.

In addition, the following components were used as components other than the modifier.
“PC” polycarbonate resin, manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: Iupilon S-2000F.
“Graft copolymer” Graft copolymer obtained by graft polymerization of acrylonitrile / styrene with a butyl acrylate-butadiene rubber polymer, manufactured by Mitsubishi Rayon Co., Ltd., trade name: MUX-30.
“Vinyl copolymer” acrylonitrile-styrene copolymer, manufactured by Mitsubishi Rayon Co., Ltd., trade name: AP-20.
"Flame retardant" triphenyl phosphate, manufactured by Daihachi Chemical Industry Co., Ltd., trade name: TPP.

Each component shown in Table 2 was mixed at each ratio (mass ratio), and shaped with a unidirectional twin-screw extruder (TEX-30α, manufactured by JSW) set at a cylinder temperature of 260 ° C. to produce pellets. Next, by using this pellet, injection molding was performed by an injection molding machine (SAV-60, manufactured by Yamashiro Seiki Seisakusho) set to a cylinder temperature of 260 ° C. and a mold temperature of 60 ° C. to obtain a combustion test piece. Table 2 shows the results of the combustion test.
As is apparent from Table 2, the modifier comprising the powder composition of the present invention exhibits flame retardancy equivalent to that of the comparative example.

[Examples 29 to 37, Comparative Examples 32 to 41: Evaluation as a modifier (II)]
The powder compositions (X-1) to (X-10), the powder compositions (Y-1) to (Y-10), and the PTFE (100%) powder are used as thermoplastic resin modifiers. The dispersibility of the obtained thermoplastic resin composition was evaluated.

Each component shown in Table 3 was mixed at each ratio (mass ratio) and shaped with a 25φ single-screw extruder set at a cylinder temperature of 280 ° C. to produce pellets. Next, using this pellet, an injection molding machine (SAV-60) set at a cylinder temperature of 280 ° C. and a mold temperature of 80 ° C. is used to perform injection molding using the same mold as the combustion test piece, and a test for dispersibility evaluation I got a piece. Table 3 shows the results of evaluation of dispersibility.
As is apparent from Table 3, the modifier comprising the powder composition of the present invention exhibits dispersibility equivalent to that of the comparative example.

  As is apparent from the above, the powder composition of the present invention exhibits dispersibility equivalent to that of a conventionally used PTFE-containing modifier and flame retardancy imparting effect derived from the anti-drip property of PTFE. The powder properties have been significantly improved.

The polytetrafluoroethylene-containing powder composition of the present invention can be used as a modifier for a thermoplastic resin composition that can cope with automation of powder measurement and an increase in the size of a transport system, and has improved handling properties.

Claims (2)

Polymer (A) particles comprising 40 to 90% by weight of polytetrafluoroethylene and 60 to 10% by weight of an organic polymer;
Containing 100 to 10 parts by mass of the polymer (A) particles, 0.1 to 10 parts by mass of organic polymer (B) particles having a glass transition temperature of 80 to 170 ° C.,
A polytetrafluoroethylene-containing powder composition, wherein at least a part of the organic polymer (B) particles are attached to the surface of the polymer (A) particles. To a slurry obtained by coagulating latex containing 100 parts by mass of polymer (A) composed of 40 to 90% by mass of polytetrafluoroethylene and 60 to 10% by mass of organic polymer, 0.1 to 10 of organic polymer (B) is obtained. After adding latex containing part by mass, a powder composition in which at least a part of the organic polymer (B) particles adhere to the surface of the polymer (A) particles is obtained through dehydration and drying steps. A method for producing a polytetrafluoroethylene-containing powder composition.