阅读说明：本技术 一种含氟热塑性弹性体、其制备方法及应用 (Fluorine-containing thermoplastic elastomer, preparation method and application thereof ) 是由 陈科 宋健 赵柯 孙斌 张万里 高自宏 于 2018-06-22 设计创作，主要内容包括：本发明公开了一种具有核壳结构的氟树脂/氟橡胶热塑性弹性体,其在破乳前为呈核层和壳层两层结构的乳胶粒子,所述核层包括10～95％的氟树脂,所述壳层包括90～5％的氟橡胶。本发明还提供了所述具有核壳结构的氟树脂/氟橡胶热塑性弹性体的制备方法。本发明提供的具有核壳结构的氟树脂/氟橡胶热塑性弹性体适合用于聚碳酸酯阻燃。(The invention discloses a core-shell structure fluororesin/fluororubber thermoplastic elastomer which is latex particles with a core layer and a shell layer structure before demulsification, wherein the core layer comprises 10-95% of fluororesin, and the shell layer comprises 90-5% of fluororubber. The invention also provides a preparation method of the fluorine resin/fluorine rubber thermoplastic elastomer with the core-shell structure. The fluororesin/fluororubber thermoplastic elastomer with the core-shell structure provided by the invention is suitable for polycarbonate flame retardance.)

1. A fluorine resin/fluorine rubber thermoplastic elastomer with a core-shell structure is characterized in that the elastomer is latex particles before demulsification, the latex particles are of a two-layer structure and comprise a core layer and a shell layer, wherein the core layer comprises fluorine resin, and the shell layer comprises fluorine rubber;

the fluororesin is at least one selected from polychlorotrifluoroethylene resin, ethylene-chlorotrifluoroethylene resin and vinylidene fluoride-chlorotrifluoroethylene resin;

the fluororubber is at least one of vinylidene fluoride-chlorotrifluoroethylene rubber, vinylidene fluoride-chlorotrifluoroethylene-hexafluoropropylene rubber and chlorotrifluoroethylene-hexafluoropropylene rubber;

in the latex particles, the mass percentage of the fluororesin is 10-95%, and the mass percentage of the fluororubber is 90-5%.

2. The fluororesin/fluororubber thermoplastic elastomer having a core-shell structure according to claim 1, characterized in that:

(1) in the core layer fluororesin:

the ethylene-chlorotrifluoroethylene resin comprises copolymerization units, by mass, of 1-35% of ethylene and 99-65% of chlorotrifluoroethylene;

the copolymerization unit of the vinylidene fluoride-chlorotrifluoroethylene resin comprises 0.1-30% of vinylidene fluoride and 99.9-70% of chlorotrifluoroethylene in percentage by mass;

(2) among the shell layer fluororubber:

the copolymerization unit of the vinylidene fluoride-chlorotrifluoroethylene rubber contains 70-30% of vinylidene fluoride and 30-70% of chlorotrifluoroethylene in percentage by mass;

the vinylidene fluoride-chlorotrifluoroethylene-hexafluoropropylene rubber comprises copolymerized units, by mass, of 79.9-35% of vinylidene fluoride, 0.1-15% of chlorotrifluoroethylene and 20-50% of hexafluoropropylene;

the chlorotrifluoroethylene-hexafluoropropylene rubber contains, in terms of mass percentage, 80-50% of chlorotrifluoroethylene and 20-50% of hexafluoropropylene in copolymerized units.

3. The fluororesin/fluororubber thermoplastic elastomer having a core-shell structure according to claim 2, characterized in that:

(1) in the core layer fluororesin:

the ethylene-chlorotrifluoroethylene resin comprises copolymerization units, by mass, of 5-20% of ethylene and 95-80% of chlorotrifluoroethylene;

the copolymerization unit of the vinylidene fluoride-chlorotrifluoroethylene resin comprises 0.5-15% of vinylidene fluoride and 99.5-85% of chlorotrifluoroethylene in percentage by mass;

(2) among the shell layer fluororubber:

the copolymerization unit of the vinylidene fluoride-chlorotrifluoroethylene rubber contains 55-35% of vinylidene fluoride and 45-65% of chlorotrifluoroethylene in percentage by mass;

the vinylidene fluoride-chlorotrifluoroethylene-hexafluoropropylene rubber comprises a copolymerization unit comprising 74-55% of vinylidene fluoride, 1-8% of chlorotrifluoroethylene and 25-35% of hexafluoropropylene in percentage by mass;

the chlorotrifluoroethylene-hexafluoropropylene rubber contains, in terms of mass percentage, 75-55% of chlorotrifluoroethylene and 25-45% of hexafluoropropylene in copolymerized units.

4. The fluororesin/fluororubber thermoplastic elastomer having a core-shell structure according to claim 3, characterized in that:

(1) in the core layer fluororesin:

the ethylene-chlorotrifluoroethylene resin comprises copolymerization units, by mass, of 10-15% of ethylene and 90-85% of chlorotrifluoroethylene;

the copolymerization unit of the vinylidene fluoride-chlorotrifluoroethylene resin comprises 1-5% of vinylidene fluoride and 99-95% of chlorotrifluoroethylene in percentage by mass;

(2) among the shell layer fluororubber:

the copolymerization unit of the vinylidene fluoride-chlorotrifluoroethylene rubber contains 45-40% of vinylidene fluoride and 55-60% of chlorotrifluoroethylene in percentage by mass;

the vinylidene fluoride-chlorotrifluoroethylene-hexafluoropropylene rubber comprises copolymerization units, by mass percentage, of 75-65% of vinylidene fluoride, 2-5% of chlorotrifluoroethylene and 23-30% of hexafluoropropylene;

the chlorotrifluoroethylene-hexafluoropropylene rubber contains, in terms of mass percentage, 70-65% of chlorotrifluoroethylene and 30-35% of hexafluoropropylene in copolymerized units.

5. The fluororesin/fluororubber thermoplastic elastomer having a core-shell structure according to claim 1, wherein the latex particles contain 30 to 80% by mass of the fluororesin and 70 to 20% by mass of the fluororubber.

6. The fluororesin/fluororubber thermoplastic elastomer having a core-shell structure according to claim 1, characterized in that the elastomer is produced by a method comprising:

(1) adding high-purity water, an emulsifier and a pH regulator into a reaction kettle, heating the reaction kettle to 10-90 ℃, adding reaction monomer gas required by fluororesin synthesis into the reaction kettle until the pressure in the reaction kettle is 0.2-5 MPa, adding an initiator to initiate polymerization, and continuously adding the reaction monomer gas required by fluororesin synthesis into the reaction kettle;

(2) when reaction monomer gas required by fluororesin synthesis is added into a reaction kettle, carrying out vacuum nitrogen replacement on the reaction kettle, so that the residual reaction monomer gas required by the fluororesin synthesis in the reaction kettle is replaced by nitrogen, wherein the mass of the reaction monomer gas required by the fluororesin synthesis is 30-80% of the total mass of the reaction monomers;

(3) heating a reaction kettle to 20-120 ℃, adding reaction monomer gas required for synthesizing fluororubber into the reaction kettle until the pressure in the reaction kettle is 0.5-8 MPa, adding a chain transfer agent, continuously adding reaction monomer gas required for synthesizing the fluororubber into the reaction kettle, and maintaining the temperature and the pressure in the kettle constant until all the reaction monomer gas required for synthesizing the fluororubber is added, wherein the mass of the reaction monomer gas required for synthesizing the fluororubber is 20-70% of the total mass of the reaction monomers;

(4) and after the polymerization reaction is finished, demulsifying, washing and drying the polymerization emulsion to obtain the fluorine resin/fluorine rubber thermoplastic elastomer with the core-shell structure.

7. The fluororesin/fluororubber thermoplastic elastomer having a core-shell structure according to claim 6, characterized in that:

the emulsifier is at least one of perfluoro caprylic acid, perfluoro ammonium caprylate alkali metal salt, hexafluoropropylene oxide oligomer carboxylic acid ammonium salt and hexafluoropropylene oxide oligomer alkali metal salt;

the pH regulator is selected from at least one of sodium dihydrogen phosphate, potassium dihydrogen phosphate and sodium tetraborate;

the initiator is selected from at least one of potassium persulfate, ammonium persulfate, sodium persulfate, potassium persulfate-sodium bisulfite, ammonium persulfate-sodium bisulfite and diisopropyl peroxydicarbonate;

the chain transfer agent is at least one selected from carbon tetrachloride, chloroform, ethylene glycol, diethyl malonate, isopentane, monofluoromethane and monofluoroethane.

8. The fluororesin/fluororubber thermoplastic elastomer having a core-shell structure according to claim 6, characterized in that:

in the step (1), the reaction temperature is 20-70 ℃, and the reaction pressure is 0.8-3 Mpa;

in the step (3), the reaction temperature is 30-90 ℃ and the reaction pressure is 1.0-5 MPa.

9. Use of the fluororesin/fluororubber thermoplastic elastomer having a core-shell structure according to claim 1, characterized in that the elastomer is used for polycarbonate flame retardancy.

10. A thermoplastic elastomer flame-retardant polycarbonate composite material, characterized in that the composite material contains 2-10% by mass of the fluorine-containing thermoplastic elastomer with a core-shell structure according to claim 1.

11. Use of a thermoplastic elastomer flame retardant polycarbonate composite according to claim 10, characterized in that the composite is used for the preparation of hot press or injection moulded shaped bodies.

12. A computer component comprising the fluorothermoplastic elastomer having a core-shell structure according to claim 1.

13. A television part comprising the fluorothermoplastic elastomer having a core-shell structure according to claim 1.

14. A component part for an electric power tool, comprising the fluorothermoplastic elastomer having a core-shell structure according to claim 1.

15. A vacuum cleaner component comprising the fluorothermoplastic elastomer having a core-shell structure according to claim 1.

Technical Field

The invention relates to a thermoplastic elastomer, in particular to a fluorine-containing thermoplastic elastomer with a flame retardant function.

Background

Since polyurethane thermoplastic elastomers were developed by bayer corporation in 1958, thermoplastic elastomers have been widely used in the fields of automobile parts, electric wires and cables, mechanical equipment, and the like because of their excellent processability and usability. With the rapid development of scientific technology in recent years, the demand for high-performance and special materials is increasing. Fluoropolymers have been the focus of research for modifying thermoplastic elastomeric materials due to their excellent properties.

With regard to the modification of thermoplastic elastomers with fluoropolymers, the prior art has made the following efforts:

(1) chinese patent CN200580040551 discloses a thermoplastic polymer composition containing fluororesin and crosslinked fluororubber, which is obtained by melt-kneading fluororesin, fluororubber and crosslinking agent together in an extruder, and dynamically crosslinking the fluororesin and fluororubber to obtain a modified thermoplastic polymer. Although the polymer prepared by the method has good heat resistance, chemical resistance, oil resistance, flexibility and molding processability, the melt mixing mode has certain limitation and is difficult to meet the problem of mixing uniformity of various fluororesins and a rubber matrix, for example, the method is only suitable for modifying vinylidene fluoride/hexafluoropropylene copolymer or vinylidene fluoride/hexafluoropropylene/tetrafluoroethylene copolymer fluororubber by using a copolymer of tetrafluoroethylene and ethylene with a melting point of 120-330 ℃;

(2) chinese patent CN201510011834 discloses a fluorosilicone thermoplastic elastomer with a rubber phase having a core-shell structure, in which the rubber phase is prepared by dispersing core-shell crosslinked rubber particles with silicone rubber as a core and fluororubber as a shell in a fluororesin matrix and mechanically mixing the components. The preparation method adjusts and controls the crosslinking degree and the crosslinking degree of the core and the shell in the core-shell particles by a mechanical mixing mode and by controlling the dosage of the crosslinking agent, and has insufficient universality;

(3) chinese patent CN201210448756 discloses a preparation method of a core-shell type double-activity acrylate elastomer, which is characterized in that acrylate containing active groups is added to modify the acrylate elastomer, and the core-shell type double-activity acrylate elastomer is prepared by an emulsion polymerization method. The core-shell type double-activity acrylate elastomer prepared by the method has good adhesive film comprehensive performance and can be used as the fluororubber for sealing, but only improves the tear resistance of the fluororubber product for sealing, and cannot simultaneously improve other properties.

For the preparation of core-shell fluorothermoplastic elastomers, the usual preparation methods mostly use physical-mechanical mixing to prepare the core-shell structure. However, it is difficult to obtain a core-shell structure thermoplastic elastomer with good controllability and high stability and repeatability by using the preparation method. In the prior art, no report is found about the preparation of core-shell structure fluororesin/fluororubber thermoplastic elastomer by using emulsion polymerization, and the improvement of the flame retardant property of the material by using the fluoroelastomer.

Disclosure of Invention

The invention aims to provide a fluororesin/fluororubber thermoplastic elastomer with a core-shell structure, which has good flame retardant property and mechanical property.

The invention provides a fluororesin/fluororubber thermoplastic elastomer with a core-shell structure, which is latex particles before demulsification, wherein the latex particles are of a two-layer structure and comprise a core layer and a shell layer, the core layer comprises fluororesin, and the shell layer comprises fluororubber;

the fluororesin is at least one selected from polychlorotrifluoroethylene resin, ethylene-chlorotrifluoroethylene resin and vinylidene fluoride-chlorotrifluoroethylene resin;

the fluororubber is at least one of vinylidene fluoride-chlorotrifluoroethylene rubber, vinylidene fluoride-chlorotrifluoroethylene-hexafluoropropylene rubber and chlorotrifluoroethylene-hexafluoropropylene rubber;

in the latex particles, the mass percentage of the fluororesin is 10-95%, and the mass percentage of the fluororubber is 90-5%.

When the core layer fluororesin comprises ethylene-chlorotrifluoroethylene resin, the ethylene-chlorotrifluoroethylene resin preferably contains 1 to 35 mass percent of copolymerized units of ethylene and 99 to 65 mass percent of chlorotrifluoroethylene.

More preferably, the copolymerized units contain 5 to 20% by mass of ethylene and 95 to 80% by mass of chlorotrifluoroethylene.

More preferably, the copolymerized units contain 10 to 15% by mass of ethylene and 90 to 85% by mass of chlorotrifluoroethylene.

When the core layer fluororesin comprises vinylidene fluoride-chlorotrifluoroethylene resin, the preferable vinylidene fluoride-chlorotrifluoroethylene resin contains 0.1-30% of vinylidene fluoride and 99.9-70% of chlorotrifluoroethylene in a copolymerization unit by mass percentage.

More preferably, the copolymerized units contain, in mass%, 0.5 to 15% of vinylidene fluoride and 99.5 to 85% of chlorotrifluoroethylene.

More preferably, the vinylidene fluoride-chlorotrifluoroethylene resin has copolymerized units including, by mass%, 1 to 5% of vinylidene fluoride and 99 to 95% of chlorotrifluoroethylene.

When the shell layer fluororubber comprises vinylidene fluoride-chlorotrifluoroethylene rubber, the preferable fluororubber/fluororubber thermoplastic elastomer with the core-shell structure contains 70-30% of vinylidene fluoride and 30-70% of chlorotrifluoroethylene by mass percentage in copolymerized units.

More preferably, the copolymerized units contain, in mass%, 55 to 35% of vinylidene fluoride and 45 to 65% of chlorotrifluoroethylene.

More preferably, the copolymerized units contain, in mass%, 45 to 40% of vinylidene fluoride and 55 to 60% of chlorotrifluoroethylene.

When the shell layer fluororubber comprises vinylidene fluoride-chlorotrifluoroethylene-hexafluoropropylene rubber, the preferable fluororubber/fluororubber thermoplastic elastomer with the core-shell structure contains the vinylidene fluoride, the chlorotrifluoroethylene and the hexafluoropropylene rubber, and the copolymerized units of the vinylidene fluoride-chlorotrifluoroethylene-hexafluoropropylene rubber contain 79.9-35% of vinylidene fluoride, 0.1-15% of chlorotrifluoroethylene and 20-50% of hexafluoropropylene in percentage by mass.

More preferably, the copolymerized units contain, in mass%, 74 to 55% of vinylidene fluoride, 1 to 8% of chlorotrifluoroethylene, and 25 to 35% of hexafluoropropylene.

More preferably, the copolymerized units contain, in mass%, 75 to 65% of vinylidene fluoride, 2 to 5% of chlorotrifluoroethylene, and 23 to 30% of hexafluoropropylene.

When the shell layer fluororubber comprises chlorotrifluoroethylene-hexafluoropropylene rubber, the chlorotrifluoroethylene-hexafluoropropylene rubber preferably contains copolymerization units of 80-50% of chlorotrifluoroethylene and 20-50% of hexafluoropropylene in percentage by mass.

More preferably, the copolymerized units contain, in mass%, 75 to 55% of chlorotrifluoroethylene and 25 to 45% of hexafluoropropylene.

More preferably, the copolymerized units contain, in mass%, 70 to 65% of chlorotrifluoroethylene and 30 to 35% of hexafluoropropylene.

The invention provides a fluororesin/fluororubber thermoplastic elastomer with a core-shell structure, which is latex particles before demulsification, wherein the latex particles are of a two-layer structure and comprise a core layer and a shell layer, wherein the core layer comprises fluororesin, and the shell layer comprises fluororubber. When the latex particles contain a fluororesin and a fluororubber, it is preferable that the mass percentage of the fluororesin and the mass percentage of the fluororubber in the latex particles are 10 to 95% and 90 to 5%, respectively.

More preferably, in the latex particles, the mass percentage of the fluororesin is 30 to 80%, and the mass percentage of the fluororubber is 70 to 20%.

The invention also provides a preparation method of the fluorine resin/fluorine rubber thermoplastic elastomer with the core-shell structure, which comprises the following steps:

(1) adding high-purity water, an emulsifier and a pH regulator into a reaction kettle, heating the reaction kettle to 10-90 ℃, adding reaction monomer gas required by fluororesin synthesis into the reaction kettle until the pressure in the reaction kettle is 0.2-5 MPa, adding an initiator to initiate polymerization, and continuously adding the reaction monomer gas required by fluororesin synthesis into the reaction kettle;

(2) when reaction monomer gas required by fluororesin synthesis is added into a reaction kettle, carrying out vacuum nitrogen replacement on the reaction kettle, so that the residual reaction monomer gas required by the fluororesin synthesis in the reaction kettle is replaced by nitrogen, wherein the mass of the reaction monomer gas required by the fluororesin synthesis is 30-80% of the total mass of the reaction monomers;

(3) heating a reaction kettle to 20-120 ℃, adding reaction monomer gas required for synthesizing fluororubber into the reaction kettle until the pressure in the reaction kettle is 0.5-8 MPa, adding a chain transfer agent, continuously adding reaction monomer gas required for synthesizing the fluororubber into the reaction kettle, and maintaining the temperature and the pressure in the kettle constant until all the reaction monomer gas required for synthesizing the fluororubber is added, wherein the mass of the reaction monomer gas required for synthesizing the fluororubber is 20-70% of the total mass of the reaction monomers;

(4) and after the polymerization reaction is finished, demulsifying, washing and drying the polymerization emulsion to obtain the fluorine resin/fluorine rubber thermoplastic elastomer with the core-shell structure.

In the above production method, the total mass of the reactive monomers in the steps (2) and (3) is the sum of the mass of the reactive monomer gas required for synthesizing the fluororesin and the mass of the reactive monomer gas required for synthesizing the fluororubber.

According to the preparation method provided by the invention, the used emulsifier can be an initiator commonly used in the field. Preferably, the emulsifier is selected from at least one of perfluorooctanoic acid, ammonium perfluorooctanoate, ammonium alkali metal perfluorooctanoate, ammonium carboxylate salt of hexafluoropropylene oxide oligomer, and alkali metal hexafluoropropylene oxide oligomer.

According to the preparation method provided by the invention, the pH regulator used can be a pH regulator commonly used in the field. Preferably, the pH adjuster is at least one selected from the group consisting of sodium dihydrogen phosphate, potassium dihydrogen phosphate, and sodium tetraborate.

According to the preparation method provided by the invention, the initiator used can be an initiator commonly used in the field. Preferably, the initiator is at least one selected from the group consisting of potassium persulfate, ammonium persulfate, sodium persulfate, potassium persulfate-sodium bisulfite, ammonium persulfate-sodium bisulfite, and diisopropyl peroxydicarbonate.

According to the preparation method provided by the invention, the chain transfer agent used can be a chain transfer agent commonly used in the field. Preferably, the chain transfer agent is selected from at least one of carbon tetrachloride, chloroform, ethylene glycol, diethyl malonate, isopentane, monofluoromethane and monofluoroethane.

According to the preparation method provided by the invention, in the step (1), the polymerization reaction temperature is 10-90 ℃. Preferably, the polymerization reaction temperature is 20-70 ℃.

According to the preparation method provided by the invention, in the step (1), the polymerization reaction pressure is 0.2-5 MPa. Preferably, the polymerization pressure is 0.8 to 3 Mpa.

According to the preparation method provided by the invention, in the step (3), the polymerization reaction temperature is 20-120 ℃. Preferably, the polymerization reaction temperature is 30 to 90 ℃.

According to the preparation method provided by the invention, in the step (3), the polymerization reaction pressure is 0.5-8 MPa. Preferably, the polymerization pressure is 1.0 to 5 MPa.

The fluororesin/fluororubber thermoplastic elastomer with the core-shell structure, which is prepared by the invention, is observed by using a transmission electron microscope, and the polymer emulsion is dyed by phosphotungstic acid and then dried at room temperature, so that the emulsion particle microspheres are observed to be in a two-layer core-shell structure.

The fluororesin/fluororubber thermoplastic elastomer with the core-shell structure is suitable for polycarbonate flame retardance.

The invention also provides a preparation method of the thermoplastic elastomer flame-retardant polycarbonate composite material, which comprises the following steps: the fluororesin/fluororubber thermoplastic elastomer with the core-shell structure and the polycarbonate are added into a high-speed mixer according to a certain proportion and mixed for 10 minutes at a high speed, then the mixture is added into a double-screw extruder and extruded and molded at 250 ℃ to obtain the thermoplastic elastomer flame-retardant polycarbonate composite material.

When the fluororesin/fluororubber thermoplastic elastomer with the core-shell structure is used for preparing the thermoplastic elastomer flame-retardant polycarbonate composite material, as a preferable mode, the mass percentage of the fluororesin/fluororubber thermoplastic elastomer with the core-shell structure in the composite material is 2-10%. When the mass percentage of the fluororesin/fluororubber thermoplastic elastomer with the core-shell structure in the composite material is 2-10%, the UL94 flame retardant grade of the composite material can reach V0 grade, and the composite material has good mechanical property and high transparency.

The thermoplastic elastomer flame-retardant polycarbonate composite material prepared by the invention is suitable for preparing a formed body formed by hot pressing or injection molding.

The invention also provides a computer part which contains the fluorine resin/fluorine rubber thermoplastic elastomer with the core-shell structure.

The invention also provides a television part which contains the fluorine resin/fluorine rubber thermoplastic elastomer with the core-shell structure.

The invention also provides a part of an electric tool, which contains the fluorine resin/fluorine rubber thermoplastic elastomer with the core-shell structure.

The invention also provides a vacuum cleaner part which contains the fluorine resin/fluorine rubber thermoplastic elastomer with the core-shell structure.

Compared with the prior art, the fluorine-containing thermoplastic elastomer provided by the invention has the following advantages:

(1) the fluorine-containing thermoplastic elastomer with the core-shell structure is prepared by adopting a continuous emulsion polymerization method for the first time, and the fluorine-containing thermoplastic elastomer with the core-shell structure, which has controllable components and uniform granularity, can be directly obtained by the chemical reaction method. The preparation method is simple to operate and easy to control, the proportion of reaction monomers is controllable, and the contents of the nuclear layer and the shell layer are adjustable;

(2) the fluorine resin/fluorine rubber thermoplastic elastomer is prepared by controlling the monomer ratio and the core-shell ratio for the first time. The fluorine-containing thermoplastic elastomer with the core-shell structure has excellent performance in the field of polycarbonate flame retardance.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to limit the invention to these embodiments. It will be appreciated by those skilled in the art that the present invention encompasses all alternatives, modifications and equivalents as may be included within the scope of the claims.