CN109689773B

CN109689773B - Coated fluoropolymer particles and polymer blends and polymer compositions comprising same

Info

Publication number: CN109689773B
Application number: CN201780040806.5A
Authority: CN
Inventors: 王胜广
Original assignee: Zhejiang Xinan Chemical Industrial Group Co Ltd
Current assignee: Zhejiang Xinan Chemical Industrial Group Co Ltd
Priority date: 2016-07-01
Filing date: 2017-05-31
Publication date: 2021-09-03
Anticipated expiration: 2037-05-31
Also published as: WO2018001028A1; CN112876790B; CN112876790A; CN112852080B; CN112852080A; CN112876791A; CN109689773A; CN112876791B

Abstract

The present invention relates to coated fluoropolymer particles, polymer blends and polymer compositions comprising the same, and methods of making the same. The coated fluoropolymer particles are free-flowing and consist of a fluoropolymer whose surface is completely or partially coated with a silicone polymer. The coated fluoropolymer particles have good dispersibility, thermal stability and flame-retardant char formation, and can be widely used in the fields of chemical industry, petroleum, textile, electronics and electrics, medical treatment, machinery and the like.

Description

Coated fluoropolymer particles and polymer blends and polymer compositions comprising same

Technical Field

The present invention relates generally to the field of polymer processing. In particular, the present invention relates to coated fluoropolymer particles, polymer blends and polymer compositions comprising the same, and methods of making the same.

Background

At present, fluoropolymers represented by tetrafluoroethylene derivative-based polymers (hereinafter referred to as tetrafluoroethylene polymers) generally have excellent high and low temperature resistance, non-stick properties, corrosion resistance, flame retardancy, and the like, and have been widely used in the fields of chemical industry, textile, electronics, electrical, medical, machinery, and the like. Tetrafluoroethylene polymers have been used as additives for anti-wear lubricants and anti-dripping agents in polymer materials, but there are several problems associated with the use of these polymers, especially tetrafluoroethylene polymers as anti-dripping agents in flame retardant polymer compositions, which result in poor appearance of extruded, injection molded, blow molded products and the like, and a serious decrease in mechanical properties of the products, apparently due to poor dispersion of the tetrafluoroethylene polymers in the polymer composition.

To compensate for the above-mentioned disadvantages and to improve the dispersibility of tetrafluoroethylene polymers in polymer compositions, a great deal of research and technical improvements have been made on tetrafluoroethylene polymers.

The patent EP-A-D,166,187 describes acrylonitrile-butadiene-styrene modified polytetrafluoroethylene powders obtained by coprecipitation, which have the disadvantage of high self-adhesion, poor free-flowing properties of the powder when the polytetrafluoroethylene content reaches 25% by weight, and no improvement in the dispersibility in polymer compositions.

Patent CN1,147,269A discloses an anti-dripping agent excellent in anti-dripping property, workability and mold release property. The core part of the antidrip agent is fibril forming high molecular weight polytetrafluoroethylene, and the shell part is non-fibril forming low molecular weight polytetrafluoroethylene, but the preparation process of the coated polytetrafluoroethylene is complicated, the shell part is softer, easy to bond under the action of external force, and poor in free flowability, and the dispersibility in the polymer composition is not improved completely.

Patent CN1,125,096C discloses a novel encapsulated tetrafluoroethylene polymer particle prepared by free radical emulsion polymerization. The coating material is selected from: polystyrene, poly-alpha-methylstyrene, styrene-acrylonitrile copolymers, alpha-methylstyrene-acrylonitrile copolymers, acrylonitrile-butadiene-styrene copolymers and mixtures thereof, the coated tetrafluoroethylene polymer particles being the type of products which are widely used on the market today in addition to pure tetrafluoroethylene polymer powder. However, in the case of a relatively high addition amount, the dispersibility thereof in the polymer composition becomes poor, the mechanical properties of the polymer composition are seriously deteriorated, and the surface of the molded article is defective. In addition, the coating material used has poor thermal stability and flame retardant char formation.

Patent CN102286157A uses acid alone as catalyst, and needs to be extracted and washed repeatedly with organic solvent such as toluene and xylene, and finally distilled to remove the solvent. The process is complex, the time consumption is long, the post-treatment is complicated and uneconomical, and because the content of Q chain links in the MQ silicon resin used for the coating material is low, super particle aggregates are easy to form, the heat resistance is poor, and when the adding amount is high, the dispersibility of the MQ silicon resin in the polymer composition is poor, and a formed product has defects.

Patent CN103849092A uses fluoropolymer powder or its condensed powder as raw material to mix with silane, so that silane permeates into the gaps of fluoropolymer, to make silane undergo in-situ polymerization reaction for 4-16 hours, and finally, the temperature is raised to boiling for removing water, and the mixture is sieved, dried at high temperature, and pulverized by air flow to obtain composite micropowder with particle size of 0.1-15 μm for high-grade coating. The product obtained by the method contains more super particle aggregates, cannot be directly used, the composite micro powder with the particle size can be obtained only by forced depolymerization through air flow crushing, and when the fluorine-containing polymer is the fluorine-containing polymer with strong fiber forming capability, the fluorine-containing polymer is fiberized in advance due to the treatment method of forced depolymerization through air flow crushing, so that the dispersibility of the fluorine-containing polymer anti-dripping agent in the polymer composition cannot be solved.

There is still a need in the art for fluoropolymer particles that are thermally stable and flame retardant char-forming, particularly with good dispersibility.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art in thermal stability, flame retardance and carbon formation, particularly dispersibility of the fluoropolymer particles.

The technical problem to be solved by the invention is solved by the following technical scheme:

according to a first aspect of the present invention, there is provided an encapsulated fluoropolymer particle, which is free-flowing and consists of a fluoropolymer whose surface is completely or partially encapsulated by a silicone polymer, prepared by a process selected from (i), (ii), (iii), (iv):

(i) emulsion hydrolysis-condensation polymerization: emulsion-hydrolyzing-condensing a silicon compound selected from the group consisting of a compound having a hydrolyzable group bonded to a silicon atom, a hydrolyzate thereof, a partial hydrolysis-condensation product thereof and a mixture thereof, in the presence of a fluoropolymer in the presence of water or a water-organic solvent as a dispersion medium and a basic compound as a catalyst, and then performing solid-liquid separation and drying;

(ii) precipitation hydrolysis-condensation polymerization method: precipitating a hydrolysis-condensation polymerization silicon compound in the presence of a fluoropolymer with an aqueous-organic solvent as a dispersion medium and a basic compound as a catalyst, followed by solid-liquid separation and drying, wherein the silicon compound is selected from the group consisting of a compound having a hydrolyzable group bonded to a silicon atom, a hydrolysate, a partial hydrolysis-condensate thereof, and a mixture thereof;

(iii) emulsion condensation polymerization: emulsifying a polysiloxane having at least two Si-OH groups in one molecule with a silicon compound having at least three hydrolyzable groups bonded to silicon atoms in one molecule, a hydrolyzate, a partial hydrolysis-condensation product, and a mixture thereof, or an organohydrido (poly) siloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule as a crosslinking agent, adding a condensation catalyst in the presence of a fluoropolymer to crosslink and cure the polysiloxane and the crosslinking agent, and then performing solid-liquid separation and drying; or

(iv) Hydrosilylation method: emulsifying an organo (poly) siloxane having at least 2 monovalent olefinically unsaturated groups in a molecule and an organohydrido (poly) siloxane having at least 2 hydrogen atoms bonded to silicon atoms in a molecule (Si-H group for short), adding a hydrosilylation catalyst in the presence of a fluoropolymer to crosslink and cure the organo (poly) siloxane and the organohydrido (poly) siloxane, and then performing solid-liquid separation and drying, wherein at least 3 monovalent olefinically unsaturated groups and at least one of the hydrogen atoms bonded to silicon atoms exist in the molecule,

the organic silicon polymer is a polymer with a cross-linking structure,

the weight ratio of the fluoropolymer to the organosilicon polymer in the coated fluoropolymer particles is 95:5 to 5: 95.

According to a second aspect of the present invention there is provided a polymer blend which is a free-flowing powder comprising the above-described encapsulated fluoropolymer particles and silicone polymer particles.

According to a third aspect of the present invention there is provided a process for preparing the above polymer blend, which comprises:

(1) (iv) performing a step selected from (i), (ii), (iii), (iv):

(i) emulsion hydrolysis-condensation polymerizing a silicon compound in the presence of a fluoropolymer with water or a water-organic solvent as a dispersion medium and a basic compound as a catalyst, wherein the silicon compound is selected from the group consisting of a compound having a hydrolyzable group bonded to a silicon atom, a hydrolyzate, a partial hydrolysis-condensate thereof, and a mixture thereof;

(ii) precipitating a hydrolysis-condensation polymeric silicon compound in the presence of a fluoropolymer with an aqueous-organic solvent as a dispersing medium and a basic compound as a catalyst, wherein the silicon compound is selected from the group consisting of compounds having a hydrolyzable group bonded to a silicon atom, hydrolyzates, partial hydrolysis-condensates thereof, and mixtures thereof;

(iii) emulsifying a polysiloxane having at least two Si-OH groups in one molecule with a silicon compound having at least three hydrolyzable groups bonded to silicon atoms in one molecule, a hydrolyzate, a partial hydrolysis-condensation product, and a mixture thereof, or an organohydrido (poly) siloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule as a crosslinking agent, and then adding a condensation catalyst in the presence of a fluoropolymer to condensation-crosslink-cure the polysiloxane and the crosslinking agent; or

(iv) Emulsifying an organic (poly) siloxane having at least 2 monovalent olefinic unsaturated groups in a molecule and an organohydrido (poly) siloxane having at least 2 hydrogen atoms bonded to silicon atoms in a molecule (Si-H groups for short), adding a hydrosilylation catalyst in the presence of a fluoropolymer, and crosslinking and curing the organic (poly) siloxane and the organohydrido (poly) siloxane, wherein at least 3 monovalent olefinic unsaturated groups and at least one of the hydrogen atoms bonded to silicon atoms exist in the molecule; and

(2) drying by solid-liquid separation to obtain the polymer blend in the form of free-flowing powder.

According to a fourth aspect of the present invention there is provided an article obtained by extrusion, injection or blow moulding or the like of said polymer blend.

According to a fifth aspect of the present invention there is provided a polymer composition comprising a polymer matrix having dispersed therein the above-described encapsulated fluoropolymer particles or polymer blend.

According to a sixth aspect of the present invention, there is provided an article obtained by extrusion, injection molding, blow molding or the like of the polymer composition.

The coated fluoropolymer particles and the polymer blend have good dispersibility, thermal stability and flame retardant char formation, and when the coated fluoropolymer particles and the polymer blend are added into a polymer as an additive to form a polymer composition, the mechanical property of the polymer composition is not obviously reduced.

Drawings

The invention is described below with reference to the accompanying drawings, in which:

FIG. 1 is a scanning electron microscope of a sample of the polymer blend prepared in example 1 of the present invention.

FIG. 2 is a scanning electron microscope of a sample of the polymer blend prepared in example 2 of the present invention.

FIG. 3 is a scanning electron microscope of a sample of the polymer blend prepared in example 4 of the present invention.

FIG. 4 is a scanning electron microscope of a sample of the polymer blend prepared in example 5 of the present invention.

FIG. 5 is a scanning electron microscope of a sample of the polymer blend prepared in example 6 of the present invention.

FIG. 6 is a scanning electron microscope showing the dispersion of polytetrafluoroethylene used in examples 1, 2, 3 and 6 of the present invention.

Detailed description of the preferred embodiments

The technical solution of the present invention is described in detail below.

Coated fluoropolymer particles

The coated fluoropolymer particles of the present invention are free-flowing and consist of a fluoropolymer whose surface is completely or partially coated with a silicone polymer.

Suitable fluoropolymers include homopolymers and copolymers comprising repeat units derived from one or more fluorinated alpha-olefin monomers.

The fluorinated alpha-olefin monomer, i.e., an alpha-olefin monomer containing at least one fluorine atom substituent. Suitable fluorinated alpha-olefin monomers are: for example CF₂＝CF₂、CHF＝CF₂、CH₂＝CF₂、CH₂＝CHF、CClF＝CF₂、CCl₂＝CF₂、CClF＝CClF、CHF＝CCl₂、CH₂CClF and CCl₂Fluoroethylenes such as ═ CClF, e.g. CF₃CF＝CF₂、CF₃CF＝CHF、CF₃CH＝CF₂、CF₃CH＝CH₂、CF₃CF＝CHF、CHF₂CHF and CF₃CH＝CH₂And the like fluoropropenes. Suitable fluoropolymers and methods for making these fluoropolymers are well known, see, for example, U.S. Pat. No. 3,671,487, U.S. Pat. No. 3,723,373, U.S. Pat. No. 3,383,092.

Suitable fluorinated alpha-olefin homopolymers include, for example, polytetrafluoroethylene, polyhexafluoropropylene, polyvinylidene fluoride, polyvinyl fluoride, polychlorotrifluoroethylene.

Suitable fluorinated alpha-olefin copolymers include copolymers containing repeat units derived from two or more fluorinated alpha-olefin copolymers, such as tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-vinylidene fluoride copolymers, and copolymers containing repeat units derived from one or more fluorinated monomers and repeat units derived from one or more non-fluorinated ethylenically unsaturated monomers copolymerizable with the fluorinated monomers, such as tetrafluoroethylene-ethylene copolymers, tetrafluoroethylene-ethylene-propylene copolymers. Suitable non-fluorinated ethylenically unsaturated monomers include, but are not limited to: for example, α -olefin monomers such as ethylene and propylene, (meth) acrylic monomers such as methyl methacrylate and butyl acrylate, vinyl ethers such as cyclohexyl vinyl ether, ethyl vinyl ether and n-butyl vinyl ether, and vinyl esters such as vinyl acetate and vinyl versatate.

Suitable fluoropolymers may or may not be fibrillatable, preferably fibrillatable in accordance with the present invention.

The fluoropolymer is preferably a tetrafluoroethylene polymer. Tetrafluoroethylene polymers which can be used are: polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-vinylidene fluoride copolymers, tetrafluoroethylene-vinyl fluoride copolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, and copolymers of tetrafluoroethylene with other copolymerizable ethylenically unsaturated monomers. These polymers are well known and are described in "Vinyl and related polymers" by Schildknecht (John Wiley & Sons, Inc., New York, 1952, p. 484-494) and "Fluoropolymers" by Woll (Wiley-Interscience, JonyWiley & Sons, Inc., New York, 1972).

The fluoropolymer is preferably Polytetrafluoroethylene (PTFE).

The Standard Specific Gravity (SSG) of polytetrafluoroethylene is not limited at all, and is usually not more than 2.230, preferably 2.130 to 2.220, more preferably 2.140 to 2.200, and smaller Standard Specific Gravity means higher molecular weight. The number average molecular weight of the above PTFE having a standard specific gravity of 2.140 to 2.200 is expressed by the formula "log₁₀(number average molecular weight) 31.83 to 11.58 × (standard specific gravity)) "approximately 2 × 10 was calculated⁶-1×10⁷。

In the present invention, the primary particles and/or secondary particle aggregates of the fluoropolymer can be selected to have an appropriate particle diameter depending on various reaction conditions, the kind of the silicon compound used, the production method, and the like. The weight ratio of fluoropolymer to silicone polymer in the coated fluoropolymer particles is preferably 95:5 to 5:95, more preferably 80: 20 to 20: 80, and most preferably 60: 40 to 60: 40.

The organic silicon polymer is a polymer with a cross-linked structure, and can be a homopolymer, a copolymer and a mixture thereof, and can also be, for example: silicone resins, condensation-type silicone rubbers and addition-type silicone rubbers and mixtures thereof.

The silicone polymer may be a first type of silicone polymer prepared by an emulsion hydrolysis-condensation or precipitation hydrolysis-condensation polymerization process having the following characteristics: containing backbone Si-O segments and T-structural units with branched structure, in which the tetrafunctional segments SiO are relative to the backbone₂(Q), trifunctional mer RSiO_3/2(T), difunctional units R₂SiO (D), monofunctional chain segment R₃SiO_1/2The ratio of (M) is preferably:

SiO₂(Q): from 0 to 70% mol, more preferably from 0 to 20% mol,

RSiO_3/2(T): from 0.1 to 100% mol, more preferably from 50 to 100% mol,

R₂SiO (D): from 0 to 30% mol, more preferably from 0 to 10% mol,

R₃SiO_1/2(M): from 0 to 30% mol, more preferably from 0 to 10% mol,

wherein, SiO₂(Q) and RSiO_3/2The proportion of the sum of the (T) units is 70 to 100 mol%, and RSiO is more preferable_3/2The chain link of (T) is 70-100% mol. Furthermore, R₂SiO (D) and R₃SiO_1/2The sum of (M) is preferably not more than 30% mol, further preferably not more than 20% mol, most preferably not more than 10% mol, and SiO is preferred₂(Q)、R₂SiO (D) and R₃SiO_1/2The sum of (M) is not more than 30% mol, more preferably not more than 20% mol. Each R is independently a monovalent organic group.

Preferably, each R is independently of the other a substituted or unsubstituted monovalent hydrocarbon group having a carbon number of 1 to 30, such as a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms; a straight or branched alkenyl group having 2 to 10 carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms; aryl optionally substituted with the above alkyl such as phenyl, naphthyl; the above alkyl group optionally substituted with an aryl group such as phenyl; some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms (fluorine, chlorine, bromine, iodine) and/or acryloxy, methacryloxy, epoxy, glycidyloxy, carboxyl, hydroxyl, mercapto, amino, sulfonic acid, nitro, amine groups, including but not limited to: alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl, aryl groups such as phenyl, tolyl, xylyl, and naphthyl, aralkyl groups such as benzyl and phenethyl, alkenyl groups such as vinyl, allyl, propenyl, butenyl, hexenyl, and heptenyl, and cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl. In R, preferably 50% or more of methyl, phenyl and vinyl groups are used, more preferably 50% or more of methyl and phenyl groups are used, and most preferably 50% or more of methyl groups are used.

In the present invention, various functional coating silicone polymers can be prepared according to the difference of R groups, such as: and a functional group such as phenyl, amino, epoxy, mercapto, sulfonic acid, alkenyl, propenyloxy, and the like.

Silicone polymers of the first type which may be mentioned are: silicone polymers and mixtures thereof consisting of basic units such as T, TQ, TQD, TQM, TD, TM, TDM or QTDM can form homopolymers from T units, copolymers from basic units such as TQ, TD, TM, TQD, TQM, TDM and TQDM, examples include but are not limited to: polymethylsiloxane, polyethyl siloxane, polyphenylsiloxane, polyvinylsiloxane, polychloromethylsiloxane, polychloroethylsiloxane, polymethylethylsiloxane, polymethylphenylsiloxane, polymethylvinylsiloxane, polyphenylvinylsiloxane, polyethylphenylsiloxane, polyethylvinylsiloxane, polymethylphenyl (vinyl) siloxane, polymethylethyl (phenyl) (vinyl) siloxane, polychloromethyl (ethyl) (phenyl) siloxane, polymethylaminopropylsiloxane, polymethylphenyl (aminopropyl) siloxane, polymethylmercaptopropyl siloxane, polymethylphenyl (mercaptopropyl) siloxane, polymethylglycidoxypropylsiloxane, polymethylphenyl (glycidoxypropyl) siloxane, polymethylacryloxypropyl siloxane, polymethylphenyl (acryloxypropyl) siloxane and the like.

In addition, other metal or nonmetal atom substitution can be made for the silicon atom in the basic skeleton of the above-mentioned silicone polymer, constituting modification of the silicone polymer, and the modification is any compound that can be co-hydrolyzed-condensed with the aforementioned silicon compound, including but not limited to: titanic acid, metal titanate, titanium chloride, titanium alkoxide, borate, and the like. The proportion of the other metal or nonmetal atom is preferably not more than 30% by mol, more preferably not more than 10% by mol, and most preferably not more than 5% by mol.

The silicone polymer may also be a silicone polymer prepared by an emulsion condensation polymerization process, the silicon compound used comprising: the organopolysiloxane (A) and the cross-linking agent (B) are obtained by emulsifying the polysiloxane (A) and the cross-linking agent (B), adding a condensation catalyst (C) in the presence of a fluoropolymer, crosslinking and curing, and then carrying out solid-liquid separation and drying.

The organopolysiloxane (a) comprises: at least two Si-OH groups are contained in one molecule. The crosslinking agent (B) is selected from: a silicon compound having at least three hydrolyzable groups bonded to silicon atoms in one molecule, or a hydrolysate, partial hydrolysis-condensate thereof, and an organohydrido (poly) siloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule. The condensation catalyst (C) is used for accelerating the crosslinking and curing of the organopolysiloxane (A) and the crosslinking agent (B) to obtain the coated fluoropolymer particles.

The silicone polymer may also be a silicone polymer having the following characteristics: has a crosslinked structure formed by a hydrosilylation reaction (may also be referred to as a hydrosilylation reaction) of a monovalent aliphatic unsaturated group bonded to a silicon atom and a hydrogen atom bonded to a silicon atom and has a structure containing the formula — (R)¹ ₂SiO_2/2)_nA cured product of a linear organosiloxane block represented by the formula, wherein n is a positive integer, which is not particularly limited, preferably 5 to EA positive integer of 5,000, each R¹Are monovalent organic radicals which are independent of one another, R here¹Have the same definitions as previously described for R.

Silicon compounds used in the preparation of silicone polymers by a hydrosilylation process (which may also be referred to as an emulsion hydrosilylation process) comprising an organo (poly) siloxane and an organohydrido (poly) siloxane, i.e. comprising: an organo (poly) siloxane having at least 2 monovalent ethylenically unsaturated groups in one molecule and an organohydrido (poly) siloxane having at least 2 hydrogen atoms bonded to silicon atoms (abbreviated as Si-H groups) in one molecule, and it is preferable that at least one of the monovalent ethylenically unsaturated groups and the hydrogen atoms bonded to silicon atoms has at least 3 monovalent ethylenically unsaturated groups in the molecule.

In the present invention, the particle diameter and morphology of the coated fluoropolymer particles are not particularly limited, and generally the volume average particle diameter is from 0.01 μm to 700. mu.m, preferably from 0.1 μm to 300. mu.m, further preferably from 0.1 μm to 100. mu.m, and most preferably from 0.1 μm to 50 μm, and it may be primary particles having a volume average particle diameter of from 0.01 μm to 100. mu.m, or secondary particle aggregates formed by aggregation of the primary particles having a volume average particle diameter of from 0.1 μm to 700. mu.m, and a detailed production method thereof will be described later.

Polymer blends

The polymer blend of the present invention is a free-flowing powder comprising the encapsulated fluoropolymer particles of the present invention and silicone polymer particles.

The proportion of fluoropolymer in the polymer blend may vary widely and is generally from 0.01% to 95% by weight, preferably from 1% to 80% by weight, more preferably from 10% to 70% by weight, most preferably from 30% to 70% by weight, based on the total weight of the polymer blend.

In one embodiment, the polymer blend consists of coated fluoropolymer particles and silicone polymer particles, wherein the fluoropolymer is present in an amount of 0.01% to 95% by weight, preferably 1% to 80% by weight, more preferably 10% to 70% by weight, most preferably 30% to 70% by weight, based on the total weight of the polymer blend. A portion of the silicone polymer is present as a coating of the fluoropolymer particles, and the remainder is present as free silicone polymer particles. The silicone polymer, which has a crosslinked structure, may be a homopolymer, a copolymer, and a mixture thereof, and may be, for example: silicone resins, condensation type silicone rubbers, addition type silicone rubbers, and mixtures thereof.

In developing the functional silicone polymer, the inventor finds that when the fluorine polymer is introduced, the silicone polymer can well coat the fluorine polymer, and can endow the fluorine polymer with more functions, such as thermal stability, toughening performance and flame retardant char formation, and particularly greatly improves the dispersion performance of the fluorine polymer in a polymer composition.

In the present invention, there is no particular limitation on the particle size and morphology of the polymer blend. The free organosilicon polymer particles may be irregular shapes such as spheres or sheets, preferably spheres, and the volume average particle diameter is preferably 0.01 μm to 100 μm, more preferably 0.1 μm to 50 μm, and most preferably 0.1 μm to 30 μm.

Process for preparing polymer blends

The process of the present invention for preparing the polymer blend may comprise subjecting the silicon compound to emulsion polymerization (herein referred to as emulsion hydrolysis-condensation polymerization) in the presence of a fluoropolymer, in particular a water-soluble basic catalyst, in the presence of water or a water-organic solvent, in particular a water-alcohol system, as the dispersing medium to obtain a precipitate, gel or dispersion (also referred to as emulsion, suspoemulsion or suspension, the same applies hereinafter) of the polymer blend, followed by solid-liquid separation and drying to obtain the polymer blend in the form of a free-flowing powder.

The process of the present invention for preparing the polymer blend may also comprise subjecting the silicon compound to precipitation polymerization (herein referred to as precipitation hydrolysis-condensation polymerization) in the presence of a basic catalyst, especially a water-soluble basic catalyst, in a water-organic solvent, especially water-alcohol, as a dispersion medium in the presence of a fluoropolymer to obtain a precipitate, gel or dispersion of the polymer blend, and drying the precipitate, gel or dispersion by solid-liquid separation to obtain the polymer blend in the form of a free-flowing powder.

The process for preparing a polymer blend according to the present invention may comprise emulsifying a polysiloxane having at least two Si-OH groups in one molecule with a compound having at least three hydrolyzable groups bonded to silicon atoms in one molecule, a hydrolyzate, a partial hydrolysis-condensation product thereof, and a mixture thereof, or an organohydrido (poly) siloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule as a crosslinking agent, adding a condensation catalyst in the presence of a fluoropolymer to crosslink-cure the polysiloxane and the crosslinking agent to obtain a dispersion of the polymer blend, and drying the dispersion by solid-liquid separation to obtain a polymer blend in the form of a powder capable of free-flowing.

The method of producing a polymer blend according to the present invention may comprise emulsifying an organo (poly) siloxane having at least 2 monovalent ethylenically unsaturated groups in one molecule and an organohydrido (poly) siloxane having at least 2 silicon-bonded hydrogen atoms (abbreviated as Si-H group) in one molecule, and then crosslinking and curing the organo (poly) siloxane and the organohydrido (poly) siloxane by adding a hydrosilylation catalyst in the presence of a fluoropolymer, wherein at least 3 of one of the monovalent ethylenically unsaturated groups and the silicon-bonded hydrogen atoms are present in the molecule to obtain a dispersion of the polymer blend, and drying the dispersion by solid-liquid separation to obtain the polymer blend in the form of a powder capable of flowing freely.

The coated fluoropolymer particles described above can be further isolated from the polymer blend.

In the present invention, there is no limitation on the form of the fluoropolymer (referred to herein as the fluoropolymer before use in the preparation of the encapsulated fluoropolymer particles of the present invention).

The fluoropolymer may be a single type of fluoropolymer fine powder particles and dispersions thereof, or may be fine powder particles of a blend of two or more fluoropolymers and dispersions thereof. The fine powder particles of the single type of fluoropolymer are known fluoropolymers, and the dispersion may be a commercially available dispersion having a certain solid content (the dispersion generally contains 2 to 10% by weight of a surfactant and a certain amount of ammonia water), and the solid content is not particularly limited, such as 30%, 50%, 60% or the like, or may be a fluoropolymer polymerization dispersion obtained by aqueous phase polymerization, and the polymerization dispersion may not need to be subjected to a concentration step, such as concentration to a solid content of 30%, 50%, 60% or the like. The fine powder particles of the blend of fluoropolymers or the dispersion thereof may be obtained by mixing a single type of fluoropolymer fine powder particles or dispersion thereof.

The fluoropolymer may also be known coated fluoropolymer fine powder particles, and the dispersion liquid may be a dispersion liquid of the fluoropolymer in water and/or an organic solvent in advance, or may be a suspension emulsion of the coated fluoropolymer in the preparation process.

The fluoropolymer is preferably mixed type fluoropolymer fine powder particles and a dispersion thereof, more preferably single type fluoropolymer particles and a dispersion thereof, more preferably polytetrafluoroethylene particles and a dispersion thereof, and most preferably polytetrafluoroethylene particles capable of fibrillation and a dispersion thereof.

The morphology, particle size and molecular weight of the fluoropolymer used can be readily determined by those skilled in the art according to the final requirements.

The polymer blends of the invention are prepared by emulsion or precipitation hydrolysis-condensation polymerization of silicon compounds, for example simply by emulsion or precipitation hydrolysis-condensation polymerization of silicon compounds in the presence of fluoropolymers in the presence of basic catalysts, using water or water-organic solvents, in particular water-alcohol systems, as dispersion medium. Emulsion hydrolysis-condensation polymerization or precipitation hydrolysis-condensation polymerization of various silicon compounds can be used to prepare the encapsulated fluoropolymer, for example, batch, semi-continuous or continuous polymerization. The fluoropolymer may be added to the reaction medium at the beginning, i.e., before any emulsion hydrolysis-condensation polymerization or precipitation hydrolysis-condensation polymerization has begun, or during the reaction, typically before 90% by weight or more of the silicon compound has been hydrolyzed-condensed.

The silicon compound used in the emulsion hydrolysis-condensation polymerization method or the precipitation hydrolysis-condensation polymerization method is any compound having a hydrolyzable group bonded to a silicon atom, a hydrolysis product thereof, a partial hydrolysis-condensation product thereof, or a mixture thereof, wherein the hydrolyzable group bonded to Si may be exemplified by, but not limited to: alkoxy, acyloxy, silyloxy, silazoxy, ketoximino, silahalo, and the like, with alkoxy having 1 to 6 carbon atoms, silyloxy, and silahalo being preferred, alkoxy being more preferred, and methoxy and ethoxy being most preferred. There is no limitation in the components, structure, and the like of the silicon compound, and the silicon compound may be exemplified by, but not limited to: methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, silicon tetrachloride, chloropropyltrichlorosilane, chloropropyltrimethoxysilane, chloropropylmethyldichlorosilane, chloropropylmethyldimethoxysilane, chloromethyltrichlorosilane, chloromethyltrimethoxysilane, chloromethylmethyldichlorosilane, chloromethyldimethylchlorosilane, dichloromethyltrichlorosilane, triethylchlorosilane, n-dodecyltrichlorosilane, octylmethyldichlorosilane, vinyltrichlorosilane, vinyldimethylchlorosilane, vinylmethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, triphenylchlorosilane, methyldiphenylchlorosilane, trimethylfluorosilane, (3, 3, 3-trifluoropropyl) methyldichlorosilane, trimethylbromosilane, trimethyliodosilane and similar halogen-containing silanes (halogen is fluorine, chlorine, bromine, iodine, preferably chlorine), tetramethoxysilane, tetraethoxysilane and similar silicates, sodium silicate and similar metal silicates, triethoxysilane, methyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, trimethylmethoxysilane and similar alkoxysilanes, methyltributanonoximosilane, vinyltributonoximosilane, methylvinyldibutonoximosilane and similar ketoximosilanes, methyltriacetoxysilane, vinyltriacetoxysilane, ethyltriacetoxysilane and similar acetoxysilanes, trimethoxysilane, trimethylsilane, methyldimethoxysilane, dimethylmethoxysilane and similar Si-H containing silanes, silicon-oxygen containing silanes, 2, 4, 6, 8-tetramethylcyclotetrasiloxane, 1, 3, 3-tetramethyldisiloxane, trimethylsilane-terminated polymethylhydrosiloxane, trimethylsilane-terminated dimethylsiloxane-methylhydrosiloxane copolymers and the like containing Si-H siloxane, hexamethyldisilazane and the like, 3-aminopropyltrimethoxysilane, bis (trimethoxysilylpropyl) amine, 3-aminopropylmethyldiethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, divinyltriaminopropyltrimethoxysilane, divinyltriaminopropylmethyldimethoxysilane, anilinomethyltrimethoxysilane, cyclohexylaminopropyltrimethoxysilane, diethylaminomethyltriethoxysilane and the like, mercaptopropyltrimethoxysilane, 1-tetramethyldisiloxane, trimethylsilane-terminated polymethylhydrosiloxane, trimethylsilane-terminated dimethylsiloxane-terminated polymethylhydrosiloxane copolymer and the like, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, divinyltriaminopropyltrimethoxysilane, Mercaptopropylmethyldimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, bis (triethoxysilylpropyl) disulfide and similar sulfur-containing silanes, 3-thiocyanatopropyltriethoxysilane and similar thiocyanosilane, 3-ureidopropyltrimethoxysilane and similar ureidosilanes, 3-isocyanatopropyltrimethoxysilane and similar isocyanatosilanes, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3, 4-epoxycyclohexane) ethyltrimethoxysilane and similar epoxysilanes, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane and similar acryloxysilane, sulfur-containing compounds, 3-glycidoxypropyltrimethoxysilane, 3-glycidyl-3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2-3-4-2- (3-4-epoxycyclohexane) ethyl-2- (3-4-epoxycyclohexane) ethyl-2-epoxycyclohexane) ethyl-2-epoxycyclohexane) ethyl-2-epoxycyclohexane) ethyl-3-epoxycyclohexane) ethyl trimethoxysilane and similar epoxycyclohexane) ethyl-3, Phenyltriethoxysilane, diphenyldimethoxysilane, methylphenyldiethoxysilane and the like phenylsilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane and the like vinylsilane, and hydrolysis products, partial hydrolysis-condensates thereof and mixtures thereof.

The polymer blends of the present invention are preferably prepared using a silane mixture, which preferably comprises:

SiX₄(Q): from 0 to 70% mol, more preferably from 0 to 20% mol,

RSiX₃(T): from 0.1 to 100% mol, more preferably from 50 to 100% mol,

R₂SiX₂(D) the method comprises the following steps From 0 to 30% mol, more preferably from 0 to 10% mol,

R₃SiX₁(M): from 0 to 30% mol, more preferably from 0 to 10% mol,

wherein RSiX must be contained₃(T) from RSiX₃(T) or RSiX₃(T) and SiX₄(Q) provides a crosslinked structure, and preferably RSiX₃(T) and SiX₄The total proportion of (Q) is 70 to 100% mol, and RSiX is more preferable₃(T) is 70-100% mol. Furthermore, R₂SiX₂(D) And R₃SiX₁The sum of (M) is preferably not more than 30% mol, more preferably not more than 20% mol, most preferably not more than 10% mol, and SiX is preferred₄(Q)、R₂SiX₂(D) And R₃SiX₁The sum of (M) is not more than 30% mol, more preferably not more than 20% mol.

R is as defined above, and preferably 50% or more by mol, more preferably 50% or more by mol, and most preferably 50% or more by mol, of R is methyl, phenyl or vinyl.

X represents a halogen atom such as chlorine, or represents a hydrolyzable group such as an alkoxy group, acyloxy group or the like, further preferably an alkoxy group.

The above mole percentages are based on the total moles of the silane mixture (the content of individual mer in the product can be estimated by testing the amount of monomer remaining in the mixture, such as by gas phase, liquid chromatography, mass spectrometry, nuclear magnetism, etc., and also by assuming complete hydrolysis-condensation of the silane compound).

It should be noted that when SiX₄The higher the (Q) content is, the more the coating material of the resulting fluoropolymer is biased toward the inorganic compound (SiO)₂) The polymer blend also has higher thermal stability and carbon forming performance. In general, when SiX₄When the content of (Q) is relatively high, for example, more than 50% by mol, it is necessary to use a water-organic solvent as a dispersion medium, preferably a water-alcohol as a dispersion medium, otherwise SiX is contained₄(Q) is very susceptible to hydrolysis, resulting in more free hydrolysates and partial hydrolysis-condensates, which affect the coating of the fluoropolymer. R₃SiX₁The amount of the compound (M) added should not be too high, otherwise it is liable to formA super particle agglomerate. Furthermore, R₂SiX₂(D) The compounds provide linear structures, can be widely used for controlling the particle size, structural properties and the like of the polymer blend of the invention, and the content thereof cannot be too high, which otherwise easily causes the reduction of product yield and the generation of super particle aggregates.

In addition, unhydrolyzed and/or uncondensed groups containing moieties bonded to silicon are allowed to exist in the polymer blend prepared by the emulsion hydrolysis-condensation polymerization method or the precipitation hydrolysis-condensation polymerization method, and examples thereof include, but are not limited to: alkoxy, acyloxy, hydrosilyl, silazoyl, silahalo, silahydroxy, and the like, preferably in amounts that do not interfere with the free-flowing properties of the polymer blend.

The polymer blend containing the coated fluoropolymer particles prepared by the emulsion hydrolysis-condensation polymerization method or the precipitation hydrolysis-condensation polymerization method of the present invention is not particularly limited, and the reaction temperature is preferably 0 to 95 ℃, more preferably 5 to 80 ℃, and still more preferably 10 to 70 ℃. Meanwhile, the reaction time including the addition time is also not particularly limited, and may be several minutes, several hours, or several days, preferably 1 to 10 hours.

The emulsion hydrolysis-condensation polymerization process or the precipitation hydrolysis-condensation polymerization process for preparing the polymer blend comprising the encapsulated fluoropolymer particles must be carried out in the presence of water in a minimum amount sufficient to satisfy the amount of silicon compound required during the emulsion hydrolysis-condensation polymerization or the precipitation hydrolysis-condensation polymerization, preferably in excess of water.

The invention uses water or water-organic solvent as reaction medium. The present invention is defined as emulsion hydrolysis-condensation polymerization and precipitation hydrolysis-condensation polymerization, respectively, depending on the reaction medium and the ratio of the reaction medium, the morphology of the fluoropolymer raw material used, and whether a surfactant is used.

The present invention is defined as emulsion hydrolysis-condensation polymerization when water is used as the dispersing medium and a fluoropolymer dispersion (usually containing a surfactant, e.g., 2-10% by weight, and commercially available fluoropolymers are usually in the range of 4-8% by weight) is used as the starting material; when water is used as a dispersion medium and powder particles containing a fluoropolymer and a surfactant are used as raw materials, the method is defined as emulsion hydrolysis-condensation polymerization; the present invention is defined as emulsion hydrolysis-condensation polymerization, wherein water is used as a dispersing medium, powder particles containing fluoropolymer are used as a raw material, and the water and the powder particles containing fluoropolymer are divided into two phases under the condition of not adding a surfactant, but the added silicon compound is rapidly combined with hydrophobic powder particles containing fluoropolymer to generate hydrolysis reaction to generate hydrophilic groups to play a role similar to the surfactant so as to disperse the powder particles containing fluoropolymer in an aqueous dispersing medium.

The water-organic solvent is used as the dispersion medium, and the water-soluble organic solvent is preferably used as the dispersion medium in the invention, because the proportion of the water and the organic solvent can be changed in a wide range. When the ratio of water to organic solvent is such that the silicon compound is completely dissolved in the dispersion medium, the silicon compound undergoes hydrolysis-condensation reaction in the presence of the fluoropolymer to produce a highly crosslinked silicone polymer which precipitates to form a precipitate, gel or dispersion, which is defined herein as precipitation hydrolysis-condensation polymerization (which is a special case of precipitation polymerization when a surfactant is present, and is conventionally referred to as dispersion polymerization), as described above, the silicon compound, after hydrolysis reaction, produces hydrophilic groups to function like a surfactant, and the precipitation hydrolysis-condensation polymerization of the present invention, and may further be dispersion hydrolysis-condensation polymerization; when the ratio of water to the organic solvent is such that the silicon compound is not completely soluble in the dispersion medium, i.e., water is used as the main dispersion medium, the polymerization method is the same as the emulsion hydrolysis-condensation polymerization described above, and the present invention is defined as the emulsion hydrolysis-condensation polymerization.

The present invention is not limited to the kind of water, and may be deionized water. Mineral water, tap water, etc., preferably water having an electric conductivity of not more than 1000. mu.S/m, more preferably water having an electric conductivity of not more than 200. mu.S/m, and most preferably water having an electric conductivity of not more than 100. mu.S/m. The organic solvent is not particularly limited, and may be optionally added or not added depending on the reaction system, and if added, a water-soluble organic solvent is preferred, and examples thereof include, but are not limited to: methanol, ethanol, isopropanol, n-butanol, acetone, etc., and more preferably the organic solvent is an alcohol organic solvent, and particularly when alkoxysilane is used as a raw material, the hydrolysate thereof is an alcohol organic solvent which is a by-product of the reaction process and a good solvent for the silicon compound. The water-insoluble organic solvent may be selected instead of the water-soluble organic solvent, such as benzene, toluene, xylene, methylene chloride, etc., depending on the purpose, such as controlling the particle size of the final product, controlling the reaction rate, etc. It should be noted that when the fluoropolymer dispersion is selected for addition in the preparation of polymer blends by the precipitation hydrolysis-condensation polymerization method, the viscosity of the system may suddenly increase due to the high proportion of organic solvent, and occasionally agglomeration may occur, but as the hydrolysis-condensation reaction of the silicon compound proceeds, the viscosity of the system may gradually decrease, and finally a precipitate, gel or dispersion of the polymer blend may be formed.

In the present invention, when water is used as the dispersion medium, it is sufficient in principle to suspend the fluoropolymer, and it is preferable that the weight ratio of the fluoropolymer to water is in the range of 1.66 to 0.001, more preferably 0.50 to 0.01, most preferably 0.30: 0.05, and if the ratio is too high, the fluoropolymer cannot be suspended, so that super particle aggregates are easily formed, and if the ratio is too low, the defects such as prolonged reaction time, reduced product yield, and reduced product performance are likely to occur; when an aqueous-organic solvent is used as the dispersion medium, it is sufficient in principle to suspend the fluoropolymer, and it is preferable that the weight ratio of the fluoropolymer to the aqueous-organic solvent is in the range of 1.66 to 0.001, more preferably 0.50 to 0.01, most preferably 0.30: 0.05, and if the ratio is too high, the fluoropolymer cannot be suspended, and the super particle aggregate is easily formed, and if the ratio is too low, the disadvantages of prolonged reaction time, reduced product yield, reduced product performance, etc. are liable to occur, and wherein the ratio of the aqueous-organic solvent is not particularly limited, and the ratio of the two may vary within a wide range, and in principle, the amount of water is sufficient to satisfy the amount required for the silicon compound in the emulsion hydrolysis-condensation polymerization or precipitation hydrolysis-condensation polymerization, and it is preferable that the amount of water is excessive.

The polymer blend containing the coated fluoropolymer particles is prepared by an emulsion hydrolysis-condensation polymerization method or a precipitation hydrolysis-condensation polymerization method, and a surfactant may be added or not, preferably a surfactant is added, as required, and the surfactant used is not particularly limited, and is preferably used in an amount of 0.01 to 20% by weight (relative to the total weight of the dispersion), more preferably 0.1 to 10% by weight. The kind of the surfactant is not particularly limited, and may be an anionic surfactant, a cationic surfactant, a zwitterionic surfactant and a nonionic surfactant, and suitable kinds of surfactants may be selected depending on the kinds of the dispersion medium, the silicon compound and the like, and may be used alone or in combination, and nonionic and anionic surfactants are preferable, for example: dodecyl trimethyl ammonium bromide, dodecyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium chloride, dodecyl dimethyl benzyl ammonium bromide, alkylphenol ethoxylates (OP) series including OP-6, OP-7, OP-8, OP-9, OP-10, OP-13, OP-15, OP-18, OP-20, etc., polyoxyethylene sorbitan (TW) series including TW-20, TW-21, TW-40, TW-80, TW-85, etc., fatty alcohol polyoxyethylene ether (O) series including AEO-8, AEO-10, AEO-15, AEO-30, etc., and mixtures thereof, further preferably nonionic surfactants.

In order to accelerate and accelerate the hydrolysis-condensation reaction of the silicon compound, a hydrolysis-condensation catalyst, for example, a hydrolysis-condensation catalyst using an acid or a base as a silicon compound, is added. Examples of the acidic catalyst include sulfuric acid, alkylsulfonic acid, hydrochloric acid, nitric acid, phosphoric acid, pyrophosphoric acid, boric acid, and chlorosilane. As the basic catalyst, there may be mentioned: alkali metals, hydroxides, alkali metal alkoxides, silanolates, quaternary ammonium bases, quaternary phosphonium bases, silanolate quaternary ammonium salts, silanolate quaternary phosphonium salts, alkali metal organic compounds, ammonia water, organic amines, carbonates, bicarbonates, and the like.

It has been found that when an acid alone is used as a hydrolysis-condensation catalyst for a silane compound, a polysiloxane resin having a low degree of crosslinking is generally obtained, which contains a large amount of incompletely condensed groups, and the degree of crosslinking needs to be increased by heating, adding a curing agent, or the like, and in the presence of a fluoropolymer, a super particle aggregate (usually several hundred micrometers to several millimeters) is easily formed.

One object of the present invention is: the silicon compound is made to form a highly crosslinked three-dimensional network organosilicon polymer coating material in the presence of the fluorine polymer relatively quickly, thereby forming a precipitate, gel or dispersion together with the fluorine polymer and reducing the binding reaction between the coating materials as much as possible, and the particle size of the primary particles of the coated fluorine polymer and the agglomerates thereof is controlled to a level that can be widely used in the market, such as the agglomerate particle size of not more than 500 μm, preferably not more than 100 μm, more preferably not more than 50 μm, most preferably not more than 30 μm. This object is achieved by the method of the invention.

In the present invention, the basic compound is selected as a catalyst for the emulsion hydrolysis-condensation polymerization and precipitation hydrolysis-condensation polymerization, and more preferably a water-soluble basic catalyst, to alkalify the water or water-organic solvent dispersion medium, such as: alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide, alkali metal carbonates such as potassium carbonate and sodium carbonate, amine compounds such as ethylamine, propylamine, butylamine, dimethylamine, trimethylamine and triethylamine, silicon alkoxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, quaternary ammonium silanol salt, quaternary phosphonium silanol salt, alkali metal organic compounds, and amines. Ammonia is preferred in the present invention because it is soluble in water, highly catalytically active and volatile, and easily removed from the product, more preferably aqueous ammonia, and most preferably aqueous ammonia containing 25 to 30% by weight of ammonia. The alkaline pH of the emulsion hydrolysis-condensation polymerization and precipitation hydrolysis-condensation polymerization reaction system is not particularly limited, but is preferably 9 to 13, more preferably 10 to 12. The reaction system is too weak in alkalinity, so that the hydrolysis and condensation time of the silicon compound and the product yield are prolonged, and the prolongation of the reaction time sometimes causes the adhesion between hydrolyzates and partial hydrolysis-condensation products of the silicon compound in different fluoropolymer coating layers to generate a super-particle polymer blend condensate; too strong basicity tends to make the coated fluoropolymer non-uniform, to form a large number of free particles not used for coating the fluoropolymer, and to generate amorphous aggregates.

As previously mentioned, hydrolysates, partial hydrolysis-condensates of silicon compounds and mixtures thereof can be used to prepare the polymer blends of the invention, for example: the silicon compound is first subjected to hydrolysis and partial hydrolysis-condensation under acidic conditions (the extent of condensation is preferably such that it does not affect the dispersion properties of the final polymer blend, as can be determined by routine experimentation), and then added to the above-mentioned basic dispersion medium containing the fluoropolymer to carry out the hydrolysis-condensation. In the present invention, whether the condensation reaction of the silicon compound is complete directly affects the free-flowing properties of the polymer blend, and any means capable of increasing the condensation reaction of the silicon compound, such as adjusting the pH, increasing the temperature, etc., may be used.

In the present invention, the polymer blend containing the coated fluoropolymer particles is prepared by the emulsion hydrolysis-condensation polymerization method and the precipitation hydrolysis-condensation polymerization method, and the addition order and the addition manner of the raw materials are not limited at all, and can be prepared simply by using, for example: mixing fluoropolymer, surfactant, water, organic solvent and catalyst together, adding silicon compound under stirring to make the silicon compound undergo the emulsion hydrolysis-condensation or precipitation hydrolysis-condensation reaction in the presence of fluoropolymer to obtain polymer blend precipitate, gel or dispersion containing fluoropolymer fully or partially coated with organosilicon polymer, making solid-liquid separation treatment, such as filtration treatment, and drying to obtain the free-flowing powder.

The emulsion condensation polymerization process of the present invention can be carried out simply by: in the presence of a fluoropolymer, a polysiloxane (A) and a crosslinking agent (B) are emulsified by a surfactant and water, then a condensation catalyst (C) is added, and crosslinking and curing are carried out to obtain a dispersion of a fluoropolymer-containing polymer blend, and after solid-liquid separation and drying, a free-flowing powder is obtained.

The polysiloxane (a) contains at least two Si — OH groups in one molecule, and the position thereof is not particularly limited, but is preferably an organic group bonded to an Si atom at the terminal of the molecular chain, which may be a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms as described for R. The molecular structure of the organopolysiloxane (a) is not particularly limited, and may be a linear structure, a linear structure with partial branching, a branched structure, or a network structure. The viscosity (25 ℃) of the organopolysiloxane (A) is not particularly limited, but is preferably 5 to 1,000,000 mPas, more preferably 5 to 50,000 mPas, most preferably 5 to 1,000 mPas, and the viscosity cannot be too high, otherwise emulsification in water is difficult.

The crosslinking agent (B) crosslinks and cures the organopolysiloxane (A) by condensation with Si-OH groups. Suitable crosslinking agents (B) include: silane compounds having at least three hydrolyzable groups bonded to silicon atoms in one molecule or their hydrolyzates, partial hydrolysis-condensates, and organohydrido (poly) siloxanes having at least three hydrogen atoms bonded to silicon atoms in one molecule, and mixtures thereof. Wherein the hydrolyzable group bonded to the silicon atom in the silane compound used as the crosslinking agent (B) contains: alkoxy, ketoximino, acyloxy, hydrosilyl, etc., and the silicon atom in the crosslinking agent (B) may be bonded with an organic group which may be a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms as described for R.

In the present invention, examples of the crosslinking agent (B) include: alkoxysilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, trimethoxysilane, tetramethoxysilane and tetraethoxysilane, and arylalkoxysilanes such as phenyltrimethoxysilane; alkenylalkoxysilanes such as vinyltrimethoxysilane; aminoalkoxysilanes such as 3-aminopropyltrimethoxysilane, bis (trimethoxysilylpropyl) amine, 3- (2-aminoethylamino) propyltrimethoxysilane, diethylenetriaminopropyltrimethoxysilane, anilinomethyltrimethoxysilane, cyclohexylaminopropyltrimethoxysilane and diethylaminomethyltriethoxysilane; sulfur-containing alkoxysilanes such as mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, and bis (triethoxysilylpropyl) disulfide; halogenated alkylalkoxysilanes such as chloromethyltrimethoxysilane and 3-chloropropyltrimethoxysilane; ketoximosilanes such as methyltributanoxime silane, vinyltributoxime silane and tetrabutoximosilane; t-and Q-type silane compounds such as acetoxysilanes including methyltriacetoxysilane, vinyltriacetoxysilane, ethyltriacetoxysilane and tetraacetoxysilane, and hydrolysates, partial hydrolysis-condensates and mixtures thereof. The alkoxysilane compound and the partial hydrolysis-condensation product of the silane compound are preferable, and a mixture of the silane compound and the partial hydrolysis-condensation product of the silane compound is most preferable as the crosslinking agent (B).

The molecular structure of the crosslinking agent (B) is not particularly limited, and may be a linear structure, a linear structure with partial branching, a branched structure, a network structure, a cyclic structure, or the like. Mention may be made, among others, of: trimethylsiloxy-terminated methylhydrogenpolysiloxane, trimethylsiloxy-terminated dimethylsiloxane-methylhydrogensiloxane copolymer, dimethylhydrogensiloxy-terminated dimethylsiloxane-methylhydrogensiloxane copolymer, cyclic methylhydrogensiloxane and organopolysiloxane in which part or all of the methyl groups are substituted by alkyl groups such as ethyl and propyl, aryl groups such as phenyl or alkenyl groups such as vinyl.

The amount of the crosslinking agent (B) is not particularly limited, and is generally: 0.1 to 60% by weight, preferably 0.1 to 30% by weight, and more preferably 1 to 20% by weight, relative to the organopolysiloxane (A). Too small an amount will not be sufficient to crosslink the cured organopolysiloxane (A), and too large an amount will be prepared by the emulsion hydrolysis-condensation or precipitation hydrolysis-condensation methods described hereinbefore in the present invention.

Other components, sometimes for the purpose of controlling the crosslinking curing reaction, controlling the structural properties of the product, etc., may be optionally added, such as: r₂SiO (D) and R₃SiO_1/2Examples of the silane compound having the structure (M) include, but are not limited to: dimethylmethoxysilane, methylphenyldimethoxysilane, methylvinyldimethoxysilane, trimethylmethoxysilane, vinyldimethylmethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyldimethylmethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, etc., andtheir hydrolyzates, partial hydrolysis-condensates. The amount of the crosslinking agent is not limited, and may be added or not added as needed in order to ensure proper curing of the organopolysiloxane (a) and the crosslinking agent (B), and is preferably not more than 10% by weight, more preferably not more than 5% by weight, based on the organopolysiloxane (a).

In the present invention, the emulsification conditions are not particularly limited, but emulsification by an emulsification dispersion machine is preferable, and examples thereof include, but are not limited to: a homomixer or a similar high-speed rotary centrifugal radial mixer, a homomixer or a similar high-speed rotary shear mixer, a homomixer or a similar high-pressure jet type emulsifying disperser, a colloid mill, an ultrasonic emulsifier, etc.

In the present invention, there is no particular limitation on the type of surfactant used, such as cationic, anionic, nonionic and amphiphilic surfactants, and further preferably anionic and nonionic surfactants, which have been described above in connection with surfactants and are not described again. The amount of the surfactant to be added is not particularly limited, but is preferably from 0.01 to 20% by weight (relative to the whole emulsion system), and more preferably from 0.1 to 10% by weight, and if the amount is too small, the requirement on the production process is high, the amount is too large, the post-treatment is troublesome, and the product performance is affected.

In the present invention, it is necessary to add a condensation catalyst (C) to accelerate the condensation crosslinking curing of the organopolysiloxane (A) and the crosslinking agent (B) to obtain a fluoropolymer-containing polymer blend. The condensation catalyst (C) used comprises: metal salts of organic acids such as stannous octoate, tin oleate, zirconium octoate, magnesium octoate, and tin octoate; titanic acid esters such as ethyl titanate, isopropyl titanate, n-butyl titanate, tert-butyl titanate, polyalkoxy titanate and the like and chelate compounds thereof; the dicarboxylic acid salt of dialkyltin such as dibutyltin dilaurate or di-n-octyltin dilaurate is preferably a metal salt of an organic acid, and more preferably a tin salt of an organic acid having not more than 10 carbon atoms. The addition method and order are not limited, but the organopolysiloxane (a), the crosslinking agent (B), the fluoropolymer, the surfactant, and water are preferably emulsified and added. The form of addition is not limited, but the condensation catalyst (C) emulsified with a surfactant and water is preferable, and the average particle diameter of the condensation catalyst (C) in the emulsion is more preferably not more than 30 μm, most preferably not more than 10 μm. The surfactants described hereinbefore can be used for the emulsification of the condensation catalyst, preferably in amounts of from 0.01 to 1000% by weight (relative to the weight of the condensation catalyst (C)). The organic solvent for dilution may be an alcohol, such as: methanol, ethanol, isopropanol, n-butanol, etc.; it may be a ketone solvent such as acetone, etc., preferably a lower alcohol having not more than 4 carbon atoms. The amount of the condensation catalyst (C) is not particularly limited, and is sufficient for the condensation crosslinking curing of the organopolysiloxane (A) and the crosslinking agent (B), preferably 0.01 to 30% by weight (relative to the total weight of the organopolysiloxane (A) and the crosslinking agent (B)), and further preferably 0.1 to 10% by weight, and is insufficient for the crosslinking curing of the organopolysiloxane (A) and the crosslinking agent (B), and the product has stickiness, which affects the free flowability of the fluoropolymer-containing polymer blend; the use amount is too much, the reaction is not easy to control, and the product performance is influenced.

In the present invention, the fluoropolymer is added in a manner not subject to any limitation, and may be added to the reaction medium at the beginning, i.e., before any condensation crosslinking curing reaction has started, or during the reaction, usually before 90% by weight or more of the silicon compound condensation crosslinking curing reaction. Which can be emulsified together with the organopolysiloxane (A) and the crosslinking agent (B); the organopolysiloxane (A) and the crosslinking agent (B) may be emulsified and then added. The reaction temperature is not particularly limited, but is preferably 1 to 80 ℃ and more preferably 4 to 70 ℃.

The condensation crosslinking solidified organic silicon polymer prepared by the method has a part used for coating the fluorine polymer and a part used as the particles of the discrete organic silicon polymer (generally, the particle size is from hundreds of nanometers to tens of micrometers, etc.), and the condensation crosslinking solidified organic silicon polymer can improve the impact property of the organic resin and can also improve the anti-adhesion property, the smoothness, the flame retardant property, etc. in the organic resin.

Another method for preparing the polymer blends of the invention is the hydrosilylation process (also known as hydrosilylation) of silicon compounds, in particular of organosilicon compounds, i.e.organosilicon polymers having a crosslinked structure are obtained by addition reaction of hydrogen atoms bonded to silicon atoms with monovalent aliphatic unsaturated groups bonded to silicon atoms.

The silicone polymer produced by the hydrosilylation method (may also be referred to as emulsion hydrosilylation method) of the silicone compound preferably contains a cured product having the formula — (R)¹ ₂SiO_2/2)_n-the linear organosiloxane blocks represented. Wherein n is a positive integer, which is not particularly limited, and is preferably a positive integer of 5 to 5,000, and each R¹The monovalent organic group is preferably a substituted or unsubstituted monovalent hydrocarbon group having a carbon number of 1 to 30 as described above for R, independently of one another.

Organosilicon compounds used in the preparation of organosilicon polymers by hydrosilylation processes comprise organo (poly) siloxanes and organohydrido (poly) siloxanes, i.e. comprise: average composition R² _aSiO_(4-a)/2An organic (poly) siloxane having at least 2 monovalent olefinic unsaturated groups in one molecule and an average composition R³ _bSiO_(4-b)/2The organohydrido (poly) siloxanes represented have at least 2 hydrogen atoms bonded to silicon atoms (abbreviated as Si-H groups) in one molecule, but it is preferred that at least one of the monovalent olefinically unsaturated groups and the hydrogen atoms bonded to silicon atoms is present in at least 3 in the molecule. In addition, in the organic (poly) siloxane and the organohydrido (poly) siloxane, the ratio of the number of moles of Si-H groups to the number of moles of monovalent olefinically unsaturated groups bonded to silicon atoms is preferably 0.01: 1 to 50: 1, more preferably 0.1: 1 to 20: 1, and still more preferably 0.5: 1 to 10: 1.

R2 is the substituted or unsubstituted C1-30 monovalent hydrocarbon group described above for R. The subscript a is a positive number satisfying 0 < a.ltoreq.3, preferably a positive number satisfying 0.01. ltoreq. a.ltoreq.3, more preferably a positive number satisfying 0.1. ltoreq. a.ltoreq.2.5, and the average formula is R² _aSiO_(4-a)/2Must have at least 2 silicon-bonded monovalent olefinically unsaturated groups per molecule and also have R²Substituted or unsubstituted other than olefinically unsaturated groups as defined in (1)Examples of the monovalent hydrocarbon group having 1 to 30 carbon atoms and the monovalent olefinically unsaturated group include, but are not limited to: vinyl, allyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, and the like, with vinyl being industrially preferred. Further, the position of the monovalent ethylenically unsaturated group in the organo (poly) siloxane is not particularly limited, and it may be bonded at a pendant position, at a terminal position, or at both positions.

The R is³Selected from H, substituted or unsubstituted monovalent hydrocarbon groups having a carbon number of 1 to 30, such as straight, branched or cyclic alkyl groups having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms; aryl optionally substituted with the above alkyl such as phenyl, naphthyl; the above alkyl group optionally substituted with an aryl group such as phenyl; some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms (fluorine, chlorine, bromine, iodine) and/or acryloxy, methacryloxy, epoxy, glycidyloxy, carboxyl, hydroxyl, mercapto, amino, sulfonic acid, nitro, amino groups, including but not limited to: alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl, aryl groups such as phenyl, tolyl, xylyl, and naphthyl, aralkyl groups such as benzyl and phenethyl, and cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl. The subscript b is a positive number satisfying 0 < b.ltoreq.3, preferably a positive number satisfying 0.01. ltoreq. b.ltoreq.3, more preferably a positive number satisfying 0.1. ltoreq. b.ltoreq.2.5, and the average formula is R³ _bSiO_(4-b)/2Must have at least 2 Si-H groups per molecule and also have R³The substituted or unsubstituted monovalent hydrocarbon group having a carbon number of 1 to 30 other than H. The position of the Si-H group in the organohydrido (poly) siloxane is not particularly limited and may be bonded at a pendant position, at a terminal position, or at both positions. In addition, it is preferable that 50 mol% or more of the substituted or unsubstituted monovalent hydrocarbon groups having 1 to 30 carbon atoms in R3 be methyl groups.

Of the organosilicon compounds composed of an organo (poly) siloxane and an organohydrido (poly) siloxane, it is preferable that at least one of the silicon-bonded monovalent ethylenically unsaturated group in the organo (poly) siloxane and the Si-H group in the organohydrido (poly) siloxane has at least 3 in its molecule, and if at least 3 are not present in any of its molecules, the resulting polymer blend becomes tacky and its dispersibility in the polymer composition is reduced.

In the present invention, the molecular weights of the organo (poly) siloxane and the organohydrido (poly) siloxane are not particularly limited, but are recommended to have a molecular weight of 100,000mm at 25 ℃²Kinematic viscosity of less than/s, more preferably 50,000mm²Kinematic viscosity below/s. The structure of the organo (poly) siloxane and the organohydrido (poly) siloxane is not particularly limited, and may be linear, cyclic, branched, or three-dimensional, and is preferably linear.

In the present invention, the preparation of polymer blends in which the fluoropolymer is wholly or partially coated with the silicone polymer by hydrosilylation of the organosilicon compound can be obtained, for example, simply by: emulsifying organic (poly) siloxane, organic hydrogenated (poly) siloxane, fluoropolymer, surfactant and water to obtain mixed emulsion, mixing with hydrosilylation catalyst, maintaining at certain temperature for certain time, addition and vulcanization to obtain polymer blend emulsion, and solid-liquid separation and drying to obtain polymer blend powder.

In the present invention, the hydrosilylation catalyst used is mainly for accelerating the curing of the organo (poly) siloxane and the mixture of organo (poly) siloxanes, and may be any of the well-known hydrosilylation catalysts, for example, platinum-based catalysts, rhodium-based catalysts, iridium-based catalysts, palladium-based catalysts, or ruthenium-based catalysts, preferably platinum-based catalysts, such as: platinum fine powder, platinum black, platinum chloride, chloroplatinic acid and chloroplatinic acid salts, alcohol-modified chloroplatinic acid, platinum-olefin complexes, platinum-alkenylsiloxane complexes, platinum-carbonyl complexes, and the like.

Furthermore, there is no limitation in the manner of addition of the hydrosilylation catalyst, which may be added to the organo (poly) siloxanes and organo hydro (poly) siloxane mixtures and fluoropolymer emulsions; or may be dissolved in a mixture of the organo (poly) siloxane and the organohydrido (poly) siloxane in advance; or may be dissolved in a solvent in advance and then added to the above emulsion or mixture; before the hydrosilylation catalyst is added to the organic (poly) siloxane and the mixture of organic (poly) siloxanes, it is preferable that the hydrosilylation reaction does not occur until the emulsification step is completed, and for example, the mixture is cooled to a low temperature of, for example, 5 ℃ or lower, and an appropriate amount of the hydrosilylation catalyst inhibitor is added to reduce the probability of the hydrosilylation reaction. The hydrosilylation reaction of the organo (poly) siloxanes and mixtures of organo (poly) siloxanes can be carried out at normal temperature, either without completion of the reaction or with heating below 100 ℃.

In the present invention, the amount of the hydrosilylation catalyst to be added is not particularly limited, provided that this amount ensures that a mixture composed of the organo (poly) siloxane and the organohydrido (poly) siloxane is suitably cured, and the hydrosilylation catalyst may be added to the reaction system of the present invention in an amount of as small as 0.001 parts by weight of the elemental platinum group metal per one million parts (ppm) of the above-mentioned mixture composed of the organo (poly) siloxane and the organohydrido (poly) siloxane, preferably 0.1ppm to 1000ppm, further preferably 0.5ppm to 100ppm, more preferably 1ppm to 50 ppm. Furthermore, for better control of the hydrosilylation reaction, any suitable hydrosilylation catalyst inhibitor may be added, which may be a well known hydrosilylation catalyst inhibitor, such as, but not limited to: acetylenic inhibitors such as 2-methyl-3-butyn-2-ol, 1-ethynyl-2-cyclohexanol (see U.S. Pat. No. 3,445,420); olefinic siloxanes (see US3,989,667), and the like.

In the present invention, in the preparation of the polymer blend by the hydrosilylation method of the organosilicon compound, the surfactant to be used is not particularly limited, and may be optionally added or not added depending on the specific preparation process. The surfactant can be anionic, cationic, zwitterionic or nonionic surfactant, the addition of the surfactant can improve the stability of the dispersed emulsion of the reaction system and is helpful for improving the regularity of the polymer blend particles, and the nonionic surfactant is further preferred, which has been described previously and is not repeated. The amount of the surfactant to be used is not particularly limited, and is preferably 0.01 to 20% by weight (relative to the total weight of the dispersion), and more preferably 0.1 to 10% by weight.

In the preparation of the polymer blend by the hydrosilylation method of the organosilicon compound according to the present invention, there is no particular limitation on the emulsification conditions, and the emulsification is preferably carried out by an emulsification disperser, which has been described above and will not be described in detail. Furthermore, the fluoropolymer may be added in any manner without limitation, and may be added to the reaction medium at the beginning, i.e., before any hydrosilylation reaction has begun, or during the reaction, typically before 90% by weight or more of the silicon compound is hydrosilylated.

In some embodiments of the present invention, any component in the form of a filler, either an inorganic filler or an organic filler, may be incorporated, sometimes for the purpose of improving certain properties of the polymer blend, such as further improving its dispersion properties, enhancing mechanical properties, improving the manufacturing process, etc. The amount to be added is not subject to any restriction and can be determined by routine experiments as required. Sometimes, to further improve the dispersion properties of polymer blends comprising encapsulated fluoropolymers in polymer compositions, the polymer compositions are recoated with metal oxide powders or silicone powders. For example, a sol of a metal oxide or a silane compound capable of hydrolysis-condensation reaction is added to a dispersion of a polymer blend containing a fluoropolymer to coat the polymer blend; the polymer blend may also be coated with metal oxide powders or condensation products of hydrolyzable silane compounds by manual or mechanical means.

According to the invention, after the hydrolysis-condensation polymerization, precipitation hydrolysis-condensation polymerization, emulsion condensation polymerization, hydrosilylation reaction, a precipitate, gel or dispersion of the polymer blend is obtained, followed by solid-liquid separation and drying, in order to obtain a polymer blend comprising fluoropolymer particles whose surface is completely or partially coated with the silicone polymer. Thus, the polymer blend powder particles can be obtained by removing moisture, organic solvents, etc. from the precipitate, gel or dispersion, or can be obtained by using heat, centrifugation, filtration, decantation or other methods, followed by washing if necessary, such as acid, alkali, surfactant, etc., and then subjecting to heat drying under normal or reduced pressure, spraying the dispersion into a hot air stream, or by using a heating medium to obtain the polymer blend powder particles of the present invention, if the fluoropolymer used is fibrillatable, the dried polymer blend is not suitable for being treated by forced pulverization such as grinding, air-jet milling, etc., which would otherwise cause premature fibrillation of the fluoropolymer.

Experimental research shows that the polymer blend prepared by the invention can contain a large amount of small-particle-size primary particles and medium-particle-size secondary particle aggregates, and can also be polymer blend aggregates with the particle size of less than 100 micrometers, even polymer blend aggregates with the particle size of less than 20 micrometers, and powder type fluoropolymers and coated fluoropolymer anti-dripping agents sold in the market generally exist in the form of aggregates, and the particle size is generally more than 300 micrometers, and generally about 500 micrometers, which is a direct reason for the fact that the addition amount of the polymer blend is not too high and the dispersing capacity is not good. In addition, when the amount of the commercially available coated fluoropolymer added is high, for example, more than 0.5% by weight, the dispersion property is seriously degraded, and the mechanical properties and flame retardancy of the polymer composition substrate are seriously affected.

The organosilicon polymer used in the polymer blend of the invention is partially present as a coating material of the fluoropolymer and partially present in a free form, and the free organosilicon polymer and the coating organosilicon polymer can be used as a polymer composition processing aid in practical application, such as an anti-wear agent, an opening agent, a toughening agent and the like. The polymer blend of the present invention can exhibit better flame retardancy and mechanical properties, especially better dispersibility, even when the particle size of the aggregate is close to that of a commercially available coated fluoropolymer, due to the presence of free silicone polymer.

Article of manufacture

The articles of the invention may be obtained by direct extrusion, injection molding, blow molding or compression molding of the polymer blends of the invention.

Extrusion, injection molding, blow molding or compression molding processes for preparing articles are well known in the art, and those skilled in the art can readily determine the specific molding process and process parameters based on the various criteria of the polymer blend and the intended use of the article, and will not be described in detail herein.

The article may be, for example: sheet, sleeve, rod, plate, gasket, component.

Polymer composition

The polymer composition of the present invention comprises a polymer matrix in which the encapsulated fluoropolymer particles or polymer blend of the present invention are dispersed.

Mention may be made, as said polymer matrix, of: vinyl polymers such as polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyalkenes such as polyethylene, polypropylene, polyalkylene terephthalates such as polybutylene terephthalate, polyethylene terephthalate, polyacrylates such as polymethyl acrylate, polymethacrylates such as polymethyl methacrylate, polyphenylene ethers, polysulfones, polycarbonates, polystyrenes, in particular high-impact polystyrene, polyamides such as nylon 6, nylon 66, polyimides, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, acrylonitrile-butadiene-styrene copolymer/polycarbonate blends, polystyrene/polyphenylene ether blends, thermoplastic polyester/polycarbonate blends such as butylene terephthalate/polycarbonate blends, silicone rubber, and mixtures thereof.

The polymer composition of the present invention preferably also contains a flame retardant, i.e. a polymer composition which is preferably flame retardant. There is no particular limitation on the flame retardant, and any known flame retardant system for polymer compositions may be used. The flame retardants used in the polymer compositions can be used singly or in combination, for example, halogenated aromatic compounds, especially brominated compounds, and antimony oxide, which have a synergistic flame retardant effect.

According to the invention, any conventional additive may be added to the polymer composition, such as: pigment, UV stabilizer, antioxidant, heat stabilizer, reinforcing filler, chain extender, colorant, toughening agent and the like.

The polymer composition may be prepared by mixing the components by any known method. Generally, there are two distinct mixing steps: premixing and melt mixing. In this step of premixing, the dry components are mixed together. The premixing is generally carried out using a tumbler mixer or ribbon blender, and a high shear mixer may also be used to prepare the premix, if desired. After premixing, it is usually melt mixed. Further, the components of the raw materials may be added directly to the feed portion of the melt mixing device without a premixing step. In melt mixing, the polymer composition components are typically melt blended in a single or twin screw extruder, extruded and cut into moldings, such as conventional pellets, granules, and the like, using standard techniques. The composition is then molded in any equipment conventionally used for molding, such as an injection molding machine of the Newbury type, an injection molding machine of the Van Dorn type.

Fluoropolymers have been used as anti-drip agents, anti-abrasion agents, etc. in flame retardant polymer compositions, and the coated fluoropolymer particles, polymer blends of the present invention have proven to be particularly useful for increasing the flame retardancy of polymer compositions, especially flame retardant polymer compositions.

The polymer composition of the present invention is preferably a flame retardant polymer composition. The flame retardant polymer composition has improved processability, dispersibility, flame retardancy and mechanical properties.

The coated fluoropolymer particles and the polymer blend not only can improve the processing and dispersing performance, the mechanical property and the apparent performance of a formed product of the fluoropolymer in a polymer composition, but also have good flame-retardant char formation property due to the existence of a large number of Si atoms in the organic silicon polymer. Even at higher fluoropolymer content in the polymer composition, the encapsulated fluoropolymer, polymer blend of the present invention readily disperses in the polymer matrix, resulting in a defect-free article surface while maintaining other excellent properties of the polymer composition.

In the polymer composition of the present invention, the amount of the coated fluoropolymer particles and the polymer blend is such that the weight content of the fluoropolymer in the polymer composition is preferably 0.01 to 30%, more preferably 0.1 to 10%, and still more preferably 0.1 to 6%.

Examples

The present invention will now be described in detail with reference to the following specific examples. However, it will be understood by those skilled in the art that the embodiments herein are for illustrative purposes only and the scope of the present invention is not limited thereto.

In the present invention, the particle size of the product is measured by a laser diffraction type particle size analyzer (Shimadzu SALD-2300) and a scanning electron microscope (ZEISS EVO18, sampling number is not less than 100), the melt index test is performed according to ASTM D1238, the izod notched impact strength test is performed according to ASTM D256, the tensile strength and elongation at break test is performed according to ASTM D638, the flexural strength test is performed according to ASTM D790, and the combustion test is performed according to the method specified in UL 94.

Example 1

Adding 800g of water, 4g of OP-10, 20g of 28% ammonia water and 100g of 60% solid content polytetrafluoroethylene dispersion (primary particle size is 0.2 mu m, SSG is 2.175) into a reaction vessel, stirring uniformly at room temperature, dropwise adding 121.6g of methyltrimethoxysilane into the reaction vessel, after about 30min, dropwise adding, increasing the system viscosity and generating solid suspended matters, continuously stirring at constant temperature for 30min, heating to 50 ℃, stirring for 2h, ending the reaction, washing, filtering, and drying in a 105 ℃ thermal cycle forced air drying oven to obtain 120g of white powder of a polymer blend with the polytetrafluoroethylene content of about 50% and the water content of less than 0.3 wt%. Sampling, and performing laser diffraction type particle size analyzer and scanning electron microscope test, wherein the polymer blend is composed of primary particle and secondary particle aggregates with average particle diameters of 0.23 μm and 13 μm, respectively, as shown in FIG. 1.

Example 2

Adding a mixture solution consisting of 150g of ethanol, 1gOP-10 g of water and 50g of methyltrimethoxysilane into a reaction container, stirring uniformly at room temperature, adding 50g of polytetrafluoroethylene dispersion liquid (the primary particle size is 0.2 mu m, the SSG is 2.175) with the solid content of 60% and 12.5g of ammonia water with the concentration of 28%, starting to generate solid suspended matters after about 1min, continuing to stir at room temperature for 15min, raising the temperature to 50 ℃, keeping the temperature for 2h, finishing the reaction, washing, filtering, and drying in a thermal cycle air blast drying oven at 105 ℃ to obtain 60g of white polymer blend powder with the polytetrafluoroethylene content of about 50% and the water content of less than 0.3 wt%. Sampling and carrying out laser diffraction type particle size analyzer and scanning electron microscope tests, wherein the obtained polymer blend mainly consists of secondary particle aggregates and has an average particle size of 61 μm as shown in figure 2.

Example 3

Adding a mixed solution consisting of 75g of ethanol, 25g of water and 61g of methyltrimethoxysilane into a reaction vessel, adding acetic acid to adjust pH to 4, stirring at room temperature for 3 hr to obtain mixed solution containing hydrolysis product and partial hydrolysis-condensation product of methyltrimethoxysilane, adding the above solution into mixed dispersion composed of 50g of polytetrafluoroethylene dispersion with solid content of 60% (primary particle diameter of 0.2 μm, SSG of 2.175), 1gOP-10, 150g of water and 25g of ammonia water, after about 1min, the system appears similar solid suspended matter, the temperature is raised to 50 ℃ after the system is continuously stirred for 15min at room temperature, the reaction is finished after the constant temperature is kept for 2h, and after washing and filtering, drying was carried out in a hot-circulation forced air drying oven at 105 ℃ to obtain 60g of a white powder of a polymer blend having a polytetrafluoroethylene content of about 50% by weight within 0.3% by weight of water content. Sampling, and performing laser diffraction type particle size analysis and measurement by a scanning electron microscope, wherein the obtained polymer blend mainly comprises secondary particle aggregates, and the average particle size of the polymer blend is 66 mu m.

Example 4

423g of a hydroxyl-terminated polydimethylsiloxane (hydroxyl content 9% by weight) and 53g of a compound of the formula (C)₂H₅O)₁₂Si₅O₄After mixing the partial hydrolysis-condensation product of ethyl orthosilicate and 25g of methacryloxypropyltrimethoxysilane, the mixture was thoroughly mixed in 150g of water containing 5g of a composite surfactant (OP-10 and sodium dodecylbenzenesulfonate in a weight ratio of 3: 2) by using a homogenizerHomogenizing and emulsifying, adding 440g polytetrafluoroethylene powder (fibrillatable, average primary and aggregate particle diameters of 0.2 μm, 350 μm, SSG of 2.175) and 300g water containing 10g of the above composite surfactant, homogenizing and emulsifying, adding 5g stannous octoate, 3g of the above composite surfactant and 100g water, emulsifying to obtain emulsion with particle diameter of about 5 μm, homogenizing, adding 800g water for dilution, transferring to a reaction vessel equipped with a stirrer, stirring at room temperature for one day to complete the reaction, stirring, washing and filtering, and spray drying to obtain 881g polymer blend free-flowing powder with water content of about 50 wt% and containing polytetrafluoroethylene with water content of 0.5 wt%. Sampling, and performing laser diffraction type particle size analyzer and scanning electron microscope test, wherein the polymer blend comprises primary particle and secondary particle aggregates with average particle diameter of 3 μm (mainly free organosilicon polymer) and 388 μm, respectively, as shown in FIG. 3.

Example 5

22.72g of a polymer having a viscosity of 30mm was added²Trimethylsiloxy-terminated dimethylsiloxane-methylhydrogensiloxane copolymer (Si-H content 0.34% by weight) in an amount of 450g with a viscosity of 600mm²Dimethylvinylsiloxy-terminated dimethylpolysiloxane (vinyl content 0.4% by weight) was introduced into a glass beaker (Si-H/vinyl molar ratio 1.16) and mixed homogeneously in a homomixer. Then 1g of OP-10 and 120g of water were added, after emulsification with a homogenizer, 350g of water was added to obtain an O/W type white emulsion, further homogeneous emulsification was carried out, 9g of the above surfactant, 850g of water and 472.72g of polytetrafluoroethylene powder (fibrillatable, average primary and aggregate particle diameters of 0.2 μm, 350 μm, SSG of 2.175 respectively) were added, after confirming uniform mixing, the obtained mixed emulsion was transferred to a reaction vessel containing 4g of the above surfactant and 780g of water, the temperature was controlled to 25 ℃ with stirring, and a mixed dissolved product composed of 1.2g of a toluene solution (platinum metal content of 0.8% by weight) of platinum-divinyltetramethyldisiloxane (Karstedt type catalyst) and 1g of the above surfactant was added, then the temperature was raised to 70 ℃, further stirring was carried out for 6 hours to obtain a suspended dispersion, while stirring and filtration and washing were carried out, finally useThe resulting dispersion was subjected to solid-liquid separation and drying in a spray dryer to obtain 943.80g (moisture content: within 0.5% by weight) of a polymer blend powder having a polytetrafluoroethylene content of about 50% by weight. The sample was sampled and subjected to a laser diffraction type granulometer test and a scanning electron microscope test, as shown in FIG. 4, and the obtained polymer blend powder had a primary average particle size of 12 μm (mainly free silicone polymer) and a secondary agglomerate average particle size of 398 μm.

The particle size of the aggregate of the fluoropolymer-containing polymer blend prepared by the emulsion hydrolysis-condensation polymerization, the precipitation hydrolysis-condensation polymerization, the emulsion condensation polymerization and the hydrosilylation method can be controlled within 500 microns, can also reach within 100 microns, even within 20 microns, and the aggregate is prepared at one time without any forced depolymerization of the polymer blend, such as grinding, air flow crushing and the like. In addition, as can be seen from scanning electron micrographs (see fig. 1-5), the polymer blend of the present invention contains substantially no fiber filaments, i.e., the product is not fibrillated in advance, and has a core-shell structure.

Example 6

Adding 360g of deionized water, 40g of absolute ethyl alcohol, 10g of 28% ammonia water, 1g of OP-10 and 60g of 60% solid content polytetrafluoroethylene dispersion (primary particle size of 0.2 μm and SSG of 2.175) into a reaction vessel, adjusting the temperature of the system to 20 ℃ and the pH value to 11.8, a mixture of 64.8g methyltrimethoxysilane, 3.1g phenyltrimethoxysilane and 4g aminopropyltriethoxysilane was added dropwise to the reaction vessel with stirring, the addition is completed within 30min, the viscosity of the reaction system is increased at the moment, solid suspended matters begin to appear, the stirring is continued for 30min, the temperature is raised to 50 ℃, after further stirring for 2h, the resulting dispersion of the polymer blend was washed, filtered under reduced pressure and then dried in a hot circulating forced air drying oven at 105 ℃ to give 72.1g of a white powder of the polymer blend having a polytetrafluoroethylene content of about 50% by weight within 0.3% by weight of water content. Sampling and carrying out laser diffraction type particle size analyzer and scanning electron microscope tests, wherein the obtained polymer blend consists of primary particle agglomerates and secondary particle agglomerates, and the average particle diameters of the polymer blend are respectively 0.26 μm and 11 μm, as shown in FIG. 5.

Example 7

The procedure was as in example 6 except that the amount of the polytetrafluoroethylene dispersion having a solid content of 60% by weight was changed to 60g, and 90.2g of a white powder of a polymer blend having a polytetrafluoroethylene content of about 60% by weight within 0.3% by weight of water content was obtained. Sampling, and performing laser diffraction type particle size analysis and measurement by a scanning electron microscope, wherein the obtained polymer blend consists of primary particle agglomerates and secondary particle agglomerates, and the average particle sizes of the polymer blend are 0.25 mu m and 13 mu m respectively.

Example 8

The procedure of example 6 was repeated except that 60g of the polytetrafluoroethylene dispersion having a solid content of 60% by weight was replaced with 40g, to obtain 60.2g of a white powder of a polymer blend having a polytetrafluoroethylene content of about 40% by weight within 0.3% by weight of water content. Sampling, and performing laser diffraction type particle size analysis and measurement by a scanning electron microscope, wherein the obtained polymer blend consists of primary particle aggregates and secondary particle aggregates, and the average particle sizes of the aggregates are 0.3 mu m and 9 mu m respectively.

By way of examples 6-8, polymer blends containing functional groups such as phenyl, amino, etc. were prepared for varying fluoropolymer content.

Comparative example 1

The preparation was carried out in the same manner as in example 1 except that the polytetrafluoroethylene dispersion having a solid content of 60% by weight was removed, to finally obtain 60g of a silicone polymer having a water content of not more than 0.3% by weight.

Comparative example 2

The procedure of example 4 was repeated except that no polytetrafluoroethylene powder was added to give 443g of a silicone polymer having a water content of 0.5% by weight or less.

Comparative example 3

The procedure of example 5 was repeated except that no polytetrafluoroethylene powder was added to give 469g of a silicone polymer having a water content of 0.5% by weight or less.

Comparative example 4

Adding 800g of water and 100g of polytetrafluoroethylene dispersion liquid (primary particle size is 0.2 μm, SSG is 2.175) with solid content of 60%, stirring uniformly at room temperature, adding dilute hydrochloric acid to adjust the pH to 3, dropwise adding 121.6g of methyltrimethoxysilane into the reaction vessel, after about 30min, dropwise adding, continuously stirring at constant temperature for 30min, heating to 50 ℃, stirring for 2h, wherein the viscosity of the system is unchanged and is still a stable emulsion system, no solid suspended matter is generated, after stirring for 6h, the system is still a stable emulsion system, heating to boiling, generating particles and viscosity, quickly condensing into irregular-shaped super particle aggregates, collecting the solid components, drying in a 105 ℃ thermal cycle air blast drying oven to obtain 119.5g of polymer mixture containing about 50% by weight of polytetrafluoroethylene and containing a large amount of hard particle super aggregates, after jet milling, the product was in the form of a powder, and some of the product had previously been fibrillated (as judged by the naked eye).

Comparative example 5

A250 ml three-necked flask equipped with a thermometer, reflux unit and stirring unit was charged with a mixture of 7.4g of 1, 3-divinyl-1, 1, 3, 3-tetramethyldisiloxane, 0.3ml of concentrated hydrochloric acid, 3ml of deionized water and 6ml of ethanol, followed by stirring, and then 50g of a concentrated dispersion of polytetrafluoroethylene (Teflon 30J, DuPont USA, 60% solids) was added dropwise over 1 hour. Then 16g of methyl orthosilicate is rapidly added for hydrolytic condensation, after 1 hour of hydrolysis, 50ml of toluene is added for extraction, after 1 hour of hydrolysis, the reaction solution is introduced into a separating funnel for layering, the water layer is divided into regions, the oil layer is washed to be neutral, and 49.7g of white powdery solid is obtained after distillation and drying to remove the toluene, wherein the polytetrafluoroethylene content is 60 percent, the white powdery solid is white microspheres of aggregates, the average particle size is 0.42mm, and the M/Q ratio in the obtained MQ silicon resin is 0.61.

Comparative example 6

1000g of polytetrafluoroethylene powder (fibrillatable, average primary and agglomerate particle diameters of 0.2 μm and 350 μm, respectively, and SSG of 2.175) was charged into a reaction vessel, 1400g of methyltrimethoxysilane was added and stirred uniformly, 0.003g of hydrochloric acid was added as a catalyst and mixed uniformly, and finally 550g of water was added and the reaction temperature was controlled not to exceed 45 ℃ for 16 hours. Heating the mixed solution to boil to remove water, filtering with 100 mesh filter cloth to obtain wet powder, drying the wet powder at 250 deg.C for 2 hr to obtain dried powder 1667g, the polytetrafluoroethylene content in the polymer blend is about 60 wt%, and the polymer blend contains a large amount of hard super particle aggregates. After the super particle aggregates are forcedly depolymerized by jet milling, the super particle aggregates are crushed into powder fiber, and part of products are previously fiberized (can be judged by naked eyes).

Example 9

10g of each of the samples of examples 1, 2, 3,4, 5, 6, 7 and 8 is put into a muffle furnace to be burnt at 300 ℃ for 5 minutes, so that almost no weight loss, no color change and no odor exist; 10g of coated PTFE product widely used in the market, namely PTFE powder (the weight ratio of PTFE/AS is 50/50) coated by AS (styrene-acrylonitrile copolymer) is put into a muffle furnace to be burnt for 5 minutes at 300 ℃, so that the coated PTFE powder has weightlessness, serious discoloration and decomposed odor; 10g of each of the samples of comparative examples 4, 5 and 6 are put into a muffle furnace to be burnt at 300 ℃ for 5 minutes, the comparative examples 4 and 6 have almost no weight loss, no color change and no odor, and the comparative example 5 has more weight loss. It can be seen that the polymer blends of the present invention comprising tetrafluoroethylene polymer have better thermal stability properties than comparative examples 4, 6 than AS-coated PTFE and MQ silicone-coated PTFE.

Examples 10 to 14 and comparative examples 7 to 13

Polymer compositions of PC (from SABIC) and polymer blends of the present invention, silicone polymer, PTFE pure powder (fibrillatable, primary particle size of 0.2 μm, agglomerate particle size of 350 μm, SSG of 2.175), free-radically polymerized coated PTFE (F449 from SABIC IP, PTFE/AS (styrene-acrylonitrile copolymer) ═ 50/50 (weight ratio)), polymer blends obtained by emulsion hydrolysis-condensation polymerization using acid alone AS a catalyst, MQ silicone resin coated PTFE, or composite micropowder obtained by polymerizing silane using acid AS a catalyst) were prepared AS shown in examples 10 to 14 and comparative examples 7 to 13 in table 1. And (3) mixing the corresponding components by a mixer, observing the mixing condition, confirming the uniform mixing, extruding and granulating by using a double-screw extruder, injecting the obtained granules into a required standard sample strip by using an injection molding machine, and finally carrying out related standard test. The polymer blend was added in an amount such that the amount of PTFE in the total amount of the composition system components was 0.4% by weight. The length-diameter ratio of the used double-screw extruder is 40, and the double-screw extruder is provided with accurate temperature control and vacuum exhaust equipment, the rotating speed of the screw is 100-700 r/min, and the extrusion working temperature is as follows: the first zone is 230-260 ℃, the second zone is 230-270 ℃, the third zone is 230-270 ℃, the fourth zone is 240-280 ℃, and the retention time is 1-2 minutes.

The dispersibility, mechanical properties and flame retardant properties of the prepared polymer compositions were characterized and the results are shown in table 1.

TABLE 1

Note: OSP stands for silicone polymer. Defects indicate more obvious spots, irregularities or fiber spots, etc

As can be seen from the test results in Table 1, the introduction of the silicone polymer coating material greatly improves the dispersion properties of the fluoropolymer in the polymer composition. However, the organosilicon polymer coated fluoropolymer prepared by polymerizing silane by using acid alone as a catalyst has no dispersion property, processability or flame retardant property in the polymer composition, which is inferior to the polymer mixture of the invention. In addition, the aggregate particle size of the polymer blend and the advanced fiberization of the fluoropolymer in the polymer blend have a significant impact on the dispersion and processability of the fluoropolymer in the polymer composition, and ultimately on the flame retardancy and mechanical properties of the polymer composition. Obviously, the polymer blend of the invention has better dispersion and processing performance in the polymer composition, and the obtained polymer composition has better mechanical property and flame retardant property.

Examples 15 to 20 and comparative examples 14 to 18

Polymer compositions of PC (polycarbonate from SABIC) and polymer blends with phenyl, amino groups of the present invention, pure PTFE powder (fibrillatable, primary particle size of 0.2 μm, agglomerate particle size of 350 μm, SSG of 2.175), free-radically polymerized coated PTFE (F449 from SABIC IP, PTFE/AS (styrene-acrylonitrile copolymer) ═ 50/50 (weight ratio)), polymer blends obtained by emulsion hydrolysis-condensation polymerization using acid alone AS a catalyst, MQ silicone resin coated PTFE, composite fine powders obtained by polymerizing silane using acid AS a catalyst) of different weight average molecular weights AS shown in table 2 were prepared in examples 15 to 20 and comparative examples 14 to 18.

TABLE 2

In the table "-" indicates not tested; defects indicate more obvious spots, irregularities or fiber spots, etc

As can be seen from the test results in Table 2, the increase in the molecular weight of the polycarbonate significantly improves the mechanical properties and flame retardant properties of the polymer composition. In addition, the flame retardant property of the polymer composition can be obviously improved by increasing the adding amount of the polymer blend, so that the polymer composition still has better apparent appearance and mechanical properties.

Although a few aspects of the present invention have been shown and discussed, it would be appreciated by those skilled in the art that changes may be made in this aspect without departing from the principles and spirit of the invention, the scope of which is therefore defined in the claims and their equivalents.

Claims

1. Coated fluoropolymer particles, characterized in that they are free-flowing and consist of a fluoropolymer whose surface is completely or partially coated with a silicone polymer, prepared by emulsion hydrolysis-condensation polymerization: emulsion-hydrolyzing-condensing a silicon compound selected from the group consisting of a compound having a hydrolyzable group bonded to a silicon atom, a hydrolyzate thereof, a partial hydrolysis-condensation product thereof and a mixture thereof, in the presence of a fluoropolymer in the presence of water or a water-organic solvent as a dispersion medium and a basic compound as a catalyst, and then performing solid-liquid separation and drying;

the organic silicon polymer is a polymer with a cross-linking structure,

the organic silicon polymer in the coated fluorine polymer particles contains main chain Si-O chain links and branched chain structure RSiO_3/2(T) structural units in which the tetrafunctional mer SiO is present relative to the main chain₂(Q), trifunctional mer RSiO_3/2(T), difunctional units R₂SiO (D), monofunctional chain segment R₃SiO_1/2The proportion of (M) is as follows:

SiO₂(Q)：0-70%mol，

RSiO_3/2(T)：0.1-100%mol，

R₂SiO(D)：0-30%mol，

R₃SiO_1/2(M)：0-30%mol，

wherein, SiO₂(Q) and RSiO_3/2(T) the sum of the units is 70 to 100 mol%, each R is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms,

the weight ratio of the fluoropolymer to the organosilicon polymer in the coated fluoropolymer particles is 95:5-5: 95.

2. The coated fluoropolymer particle of claim 1, wherein the silicone polymer in the coated fluoropolymer particle comprises backbone Si-O segments and has a branched structure RSiO_3/2(T) structural units in which the tetrafunctional mer SiO is present relative to the main chain₂(Q), trifunctional mer RSiO_3/2(T), difunctional units R₂SiO (D), monofunctional chain segment R₃SiO_1/2The proportion of (M) is as follows:

SiO₂(Q)： 0-20%mol，

RSiO_3/2(T)：50-100%mol，

R₂SiO(D)：0-10%mol，

R₃SiO_1/2(M)：0-10%mol，

wherein, SiO₂(Q) and RSiO_3/2The sum of the units (T) accounts for 70 to 100 mol%, and each R is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms.

3. The coated fluoropolymer particle of claim 1 or 2, wherein the fluoropolymer is selected from a homopolymer, a copolymer or a mixture thereof comprising repeating units derived from one or more fluorinated alpha-olefin monomers.

4. The coated fluoropolymer particle of claim 1 or 2, wherein the fluoropolymer is selected from fibrillated fluoropolymers.

5. The coated fluoropolymer particle of claim 1 or 2, wherein the coated fluoropolymer particle has a volume average particle size of 0.01 μm to 700 μm.

6. The coated fluoropolymer particle according to claim 1 or 2, wherein the fluoropolymer is selected from: polytetrafluoroethylene, polyhexafluoropropylene, polyvinylidene fluoride, polyvinyl fluoride, polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-vinylidene fluoride copolymers, tetrafluoroethylene-vinyl fluoride copolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers and copolymers of tetrafluoroethylene with other copolymerizable ethylenically unsaturated monomers, or mixtures thereof.

7. A polymer blend which is a free-flowing powder characterized in that it comprises the encapsulated fluoropolymer particles of any one of claims 1-6 and silicone polymer particles.

8. The polymer blend according to claim 7, wherein the fluoropolymer is present in an amount of 0.01 to 95% by weight based on the total weight of the polymer blend.

9. Process for preparing a polymer blend according to claim 7 or 8, characterized in that it comprises:

(1) the following steps are carried out: emulsion hydrolysis-condensation polymerizing a silicon compound in the presence of a fluoropolymer with water or a water-organic solvent as a dispersion medium and a basic compound as a catalyst, wherein the silicon compound is selected from the group consisting of a compound having a hydrolyzable group bonded to a silicon atom, a hydrolyzate, a partial hydrolysis-condensate thereof, and a mixture thereof; and

10. A polymer composition comprising a polymer matrix in which the coated fluoropolymer particles of any one of claims 1-6 or the polymer blend of any one of claims 7-8 are dispersed.

11. The polymer composition according to claim 10, wherein the polymer matrix is selected from the group consisting of: polycarbonates, polyphenylene ethers, polyalkylene terephthalates, vinyl polymers, polyalkenes, polyacrylates, polymethacrylates, polystyrenes, high impact polystyrene, polysulfones, polyamides, polyimides, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, acrylonitrile-butadiene-styrene copolymers, silicone rubbers and blends thereof.

12. A polymer composition according to claim 10 or 11, wherein the amount of the coated fluoropolymer particles or polymer blend is such that the fluoropolymer is present in the polymer composition in an amount of 0.01-30% by weight.