JPH0428747B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application] The present invention relates to a fluoropolymer alloy made from a melt-processable ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer and one or more other polymers; Concerning their manufacture and use. BACKGROUND OF THE INVENTION Fluoropolymer alloys are new materials that have different properties than the parent polymers from which they are made. The advantages of using commercially available polymers, simple processes, and easy formulation make their preparation an important method for producing new materials with a wide variety of useful properties. Recently, interest has been gathering in Takaomi Satokawa, Plastics, 32, 69 (1981). Reported fluoropolymer alloys include blend polymers whose main component is polyvinylidene fluoride, as well as polytetrafluoroethylene (PTFE) dispersions and tetrafluoroethylene-hexafluoropropylene copolymers (FEP).
Limited to blend polymers whose main component is a dispersion (British Patent No. 935706 (1960),
No. 37-12521). Polytetrafluoroethylene (PTFE), commonly referred to as the "king of plastics", has excellent comprehensive properties. It also has excellent thermal and chemical stability, as well as remarkable electrical insulation and non-stick properties. However, it can only be formed by cold compression and subsequent sintering. Also, its creep resistance is low. Therefore, its use is limited. Tetrafluoroethylene-hexafluoropropylene copolymer (FEP) is a copolymer of tetrafluoroethylene and hexafluoropropylene that has good creep resistance, and the presence of trifluoromethyl in the copolymer chain makes it difficult to melt. Can be molded. The chemical inertness and remarkable electrical insulation properties of the copolymer are similar to polytetrafluoroethylene, but its thermal stability is not as good as PTFE and can only withstand temperatures up to 200℃. and its price is higher than PTFE. [Problem to be Solved by the Invention] The purpose of the present invention is to produce a fluorine-containing polymer alloy with more complete properties through a blend of PTFE and FEP. The method for producing polymer alloys made from PTFE and FEP is described in British Patent No. 935706 (1960) and Japanese Patent Publication No. 935706 (1960)
No. 37-12521, which utilizes co-precipitation of these two fluoropolymer dispersions. However, the process is time consuming and costly. Also, the mechanical properties of fluoropolymer alloys are poor compared to those of PTFE and FEP, for example their tensile strength is much lower than that of the two parent polymers and only slightly lower at room temperature.
It is 142-213Kg/ ^cm2 . One of the important issues is to match PTFE and FEP in order to obtain a good fluoropolymer alloy made from PTFE and FEP. These two raw fluoropolymers have different processing temperatures and different thermal stabilities. The melt compression molding temperature of FEP is approximately 310°C, while the sintering temperature of PTFE after cold compression is approximately 380°C. The decomposition rate of FEP at such temperatures is high. In particular, when FEP resins with carboxyl end groups are produced by copolymerization using persulfates as initiators, they must be sintered at 380° C. to stabilize the end groups. However, FEP resin develops "surface wrinkles" after sintering and cannot be blended with PTFE powder. Another important issue is the blending process of producing polymer alloys made from PTFE and FEP. Generally, polymers are blended by a solution blending method, a melt blending method, or a dispersion coprecipitation blending method. Solvents have not yet been found for PTFE and FEP, so these cannot be done by solution blending. Similarly, PTFE cannot be melt processed and therefore cannot be melt blended. Dispersion co-precipitation blends are therefore the only solution, as described in British Patent No.
Although it is adopted in Japanese Patent Publication No. 935706 and Japanese Patent Publication No. 37-12521, the cost of the polymer alloy increases because an expensive fluorine-containing emulsifier is used to prepare a dispersion of PTFE and FEP. In addition, the coprecipitation blending method has the disadvantage of being relatively time consuming. One object of the present invention is to provide a fluoropolymer alloy made from ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer (abbreviated as EHMW-FEP) as its main component. EHMW-FEP is characterized by having melt processing properties and being compatible with PTFE. A second object of the present invention is the dry powder co-milling for producing fluoropolymer alloys.
powder co-mill) or wetted powder co-mill
The objective is to provide a blending method for powder co-mill. A third object of the present invention is to have melt forming processing properties like FEP and cold compression and sintering properties like PTFE, and is characterized by having excellent properties that both PTFE and FEP have. The object of the present invention is to provide a fluoropolymer alloy that can be used as a fluoropolymer. A fourth object of the present invention is to provide a series of fluoropolymer alloys made from EHMW-FEP as their main component and at least one other polymer, including fluorine-containing polymers or conventional polymers. It is about providing. [Means for Solving the Problems] According to the present invention, (A) a weight average molecular weight of 2×10 ⁵ or more, a melt viscosity of 1×10 ⁶ poise or more, and a melt flow index of 0.8 g/10 min or less; A melt-processable ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer having a hexafluoropropylene content of 12 to 30% by weight.
0.1 to 99.9% by weight; (B) polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-ethylene copolymer, polysulfone, polyethylene, polypropylene, polyimide, polycarbonate, polyphenylene oxide, and polyphenylene oxide; At least one polymer selected from the group consisting of enylene sulfide 99.9 to 0.1
% by weight and is characterized in that it is a powder blend made by co-milling a dry powder and a wet powder. Furthermore, according to the present invention, the above EHMW-FEP(A)
and another polymer (B) are separately pulverized, and then the polymers are mixed at a predetermined weight ratio while being pulverized homogeneously until they pass through a 40-mesh sieve. A manufacturing method by co-pulverizing dry powder, and moistening EHMW-FEP (A) and another polymer (B) with water, ethyl alcohol, ethyl acetate, or a mixed solvent thereof,
There is provided a method for producing a fluoropolymer alloy by wet powder co-milling, which is then milled to homogeneity, filtered and dried to obtain a final product that passes through a 40 mesh sieve. [Operation and embodiments of the invention] The ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer (EHMW-FEP) used in the present invention is a molding powder that can be melt-molded, and has a melt viscosity of 1×10 ⁶ poise or more and 0.8 g/
Melt flow index less than 10 minutes, hexafluoropropylene content of 12-30% by weight, 2 x ¹⁰⁵
It has a weight average molecular weight of 272 Kg/cm ² or more at room temperature. EHMW-FEP having such properties has good compatibility (miscibility) with polytetrafluoroethylene in the fluoropolymer alloy.
For example, a fluoropolymer alloy consisting of 10% EHMW-FEP and 90% PTFE has almost only one melting peak and one melting peak in its DSC spectrum.
It has two crystallization peaks. Therefore, a fluoropolymer alloy can be easily produced by the dry powder co-pulverization method or the wet powder co-pulverization method without using the conventional dispersion coprecipitation method which requires time and cost. The manufacturing method of EHMW-FEP that can be melt processed is as follows:
It is a solution precipitation polymerization using liquid hexafluoropropylene as the solvent, increasing the monomer concentration in the reaction zone over the entire period by increasing the amount of monomer in the autoclave, and also increasing the monomer concentration in the reaction zone during the entire period by increasing the amount of monomer in the autoclave. By increasing the amount of tetrafluoroethylene in the initial monomer mixture of Including reducing the possibility of polymer chain termination. All of these conditions are
It is advantageous for growing copolymer chains and producing higher molecular weight copolymers. The polymerization conditions are as follows: 1) A mixture of tetrafluoroethylene and hexafluoropropylene is charged into an autoclave at a rate of 0.2-0.5 g/ml. 2) The weight ratio of tetrafluoroethylene in the initial monomer mixture of tetrafluoroethylene and hexafluoropropylene is between 11 and 50%. 3) The initiator diisopropyl percarbonate (IPP) is 0.001-0.05% based on monomer. 4) The weight ratio of water and monomer is 3:1 to 1:1,
The polymerization temperature is 40 to 80°C, the polymerization pressure is 20 to 30 kg/cm ² , and the polymerization time is 1 to 5 hours per batch. According to the invention, the PTFE used is a commercially available resin that includes a resin produced by suspension polymerization or dispersion polymerization and has a tensile strength of 270 Kg/cm ² or more at room temperature. According to the invention, other commercial resins such as polychlorotrifluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-ethylene copolymer, polyethylene, polypropylene, polysulfone, polyimide, polycarbonate, polyphenylene oxide, polyphenylene sulfate, etc. can be used to produce fluoropolymer alloys with EHMW-FEP. The EHMW-FEP and one or more other polymers, as described above, are separately ground in a mill and then milled and mixed until thoroughly mixed. The mixed powder passes through 40-80 meshes,
This completes the processing preparation. The milling and mixing process of two or more polymers is carried out either in dry powder form or in wet powder form. During wet mill mixing, the polymer is moistened with water, ethyl alcohol, ethyl acetate or a mixture of these solvents. When mixing is complete, the polymer mixture is dried and sieved. In a fluoropolymer alloy made from EHMW-FEP and PTFE, the weight of EHMW-FEP is 0.1-99.9% and the weight of PTFE is 99.9-0.1%. In a preferred embodiment, the fluoropolymer alloy comprises 0.1-60% EHMW-FEP and 40-60% PTFE.
Contains 99.9%. EHMW-Fluoropolymer alloy made from FEP and PTFE can be heated at 300-353℃ like FEP.
It can be melted and compressed into products at a temperature of 50~200Kg/cm2 and a pressure of 50~200Kg/ ^cm2 . These are also 50~ like PTFE
Cold compressed under pressure of 200Kg/ ^cm2 , then 300~
Can be sintered at a temperature of 390℃. The temperature at which the fluoropolymer alloy is melt-pressed or sintered depends on the PTFE content.
The higher the PTFE content, the higher the processing temperature. The fluoropolymer alloy made from EHMW-FEP and PTFE of the present invention not only has creep resistance similar to FEP, but also high tensile strength at high temperatures similar to PTFE. this is,
Tensile strength of 200-400Kg/ ^cm2 and 300-700% at room temperature
elongation and tensile strength of 50-200Kg/ ^cm2 at 200℃
It has an elongation of 300-700%. The above fluoropolymer alloy includes glass fiber,
It can be reinforced and modified by adding graphite, molybdenum disulfide, carbon, and various metal powders. [Effects of the Invention] EHMW-FEP used in the present invention can be melt-molded and has good compatibility (miscibility) with other polymers such as polytetrafluoroethylene in the fluoropolymer alloy. Therefore,
A series of fluoropolymer alloys can be readily obtained from EHMW-FEP and at least one other polymer (fluorine-containing polymer or conventional polymer) by powder blending methods, such as the EHMW-FEP of the present invention.
Fluoropolymer alloys consisting of FEP and PTFE are materials with excellent thermal stability, chemical inertness and remarkable electrical insulation properties. This type of fluoropolymer alloy is used for various diaphragms, seals, lined valves, lined pipes,
It can be processed into various parts of pumps such as lining pumps, bodies, and impellers, as well as wound and coated wires. Products made from fluoropolymer alloys have better creep resistance than those made from PTFE and therefore have a relatively long operating life. The above fluoropolymer alloy can be used for powder coating by electrostatic method or fluidized bed method,
It can also be processed into complex products by employing ram extrusion of a paste consisting of a fluoropolymer alloy and petroleum ether or kerosene as a wetting agent. [Example] Hereinafter, the present invention will be specifically described with reference to Examples. However, it goes without saying that the present invention is not limited to these Examples in any way. In each example, "parts" and "%" are based on weight unless otherwise specified. Example 1 Melt flow index 0g/10min
Wet 20 g of EHMW-FEP and 180 g of PTFE with a mixture of ethyl alcohol and ethyl acetate,
It was subsequently ground, filtered, dried and passed through a 40 mesh sieve. The resulting powder was cold pressed into a 2 mm thick sheet under a pressure of 80 Kg/cm ² and sintered at 350° C. for 1 hour. After cooling, the tensile strength of the sheet obtained was 277 Kg/cm ² at room temperature. Example 2 EHMW-FEP and PTFE were mixed at a weight ratio of 1/9, 1/3, 1/1, 3/1, and 9/1, respectively, and the resulting mixture was passed through a 40-mesh sieve. It was ground, cold pressed at 80Kg/cm ² and sintered. Table 1 shows the properties of the obtained fluoropolymer alloy.

[Table] Example 3 EHMW-FEP and tetrafluoroethylene-ethylene copolymer (F40) were mixed in the weight ratio shown in Table 2 by blending the dry powder with the wet powder, and the resulting fluoropolymer alloy was 150Kg/ ^cm2
By cold pressing and then sintering under a pressure of
Or molded by melt compression.

[Table] Example 4 A mixture of 40 g of EHMW-FEP, 40 g of PTFE, and 10 g of polysulfone was moistened with acetone, mixed homogeneously with a high-speed stirrer, ground, dried, sieved through a 40-mesh sieve, and cooled at 80 kg/cm ² . compress, then
It was sintered at 320°C for 1 hour. The hardness (Rockwell) of the obtained fluoropolymer alloy was D50. Example 5 EHMW-FEP and polychlorotrifluoroethylene (CTFE) were mixed by dry powder or wet powder blending in the weight ratios shown in Table 3, and the resulting fluoropolymer alloy was mixed at a weight ratio of 70 to 150 Kg/ ^cm2 . By cold pressing under pressure and then sintering,
Or molded by melt compression.

[Table] Example 6 EHMW-FEP and polyvinylidene fluoride (PVDF) were mixed by blending dry powder or wet powder (diisobutylacetone was used as a wetting agent) in the weight ratio shown in Table 4, and the resulting fluorocarbon The polymer alloys were processed by cold pressing and sintering under pressures of 70-150 Kg/cm ² or by melt pressing.

[Table] Example 7 EHMW-FEP and polysulfone (PS) were mixed by blending dry powder or wet powder (chloroform was used as a solvent) in the weight ratio shown in Table-5, and the resulting fluoropolymer alloy was ~
Molding was carried out by melt compression under a pressure of 150 Kg/cm ² .

[Table] Example 8 EHMW-FEP and polyethylene (PE) were mixed by blending dry powder or wet powder (xylene was used as a solvent) in the weight ratio shown in Table 6, and the resulting fluoropolymer alloy was ~150
Molding was carried out by melt compression under a pressure of Kg/cm ² .

[Table] Example 9 EHMW-FEP and polypropylene (PP) were mixed by blending dry powder or wet powder (decalin was used as a solvent) in the weight ratio shown in Table-7, and the resulting fluoropolymer alloy was ~
Molding was carried out by melt compression under a pressure of 150 Kg/cm ² .

[Table] Example 10 EHMW-FEP was mixed with polycarbonate (PC) by blending dry powder or wet powder (chloroform was used as a solvent) in the weight ratio shown in Table-8, and the resulting fluoropolymer alloy was mixed with polycarbonate (PC) in the weight ratio shown in Table-8.
Molding was carried out by melt compression under a pressure of 70-150 Kg/ ^cm2 .

[Table] Example 11 Fluoropolymer obtained by mixing EHMW-FEP and polyphenylene oxide (PPO) in the weight ratio shown in Table 9 by blending dry powder or wet powder (chloroform was used as a solvent). The alloy was processed by melt compression under a pressure of 70-150 Kg/ ^cm2 .

[Table] Example 12 EHMW-FEP and polyphenylene sulfide (PPS) were mixed in the weight ratio shown in Table 10 using a blend of dry powder or wet powder, and the resulting fluoropolymer alloy was mixed at a weight ratio of 70 to 150 kg/cm. Molding was performed by melt compression under a pressure of ² .

[Table] Example 13 EHMW-FEP and polyimide (PI) were mixed by dry powder or wet powder blending in the weight ratio shown in Table-11, and the resulting fluoropolymer alloy was heated at a pressure of 70 to 150 Kg/cm ² Melt compression under or
The molding process was performed by cold pressing and sintering under a pressure of 70-150 Kg/ ^cm2 .

[Table] Example 14 10 g of EHMW-FEP and 90 g of molded powder or dispersed powder of PTFE were mixed, and the resulting mixture was then ground and sieved through 40 meshes. The resulting dry powder of fluoropolymer alloy was moistened with 200% gasoline, cold pressed, and sintered. This fluoropolymer alloy product can be used for lining valves and tubing. Example 15 40 g of fluoropolymer alloy made from EHMW-FEP and PTFE, 10% by weight each, 20
% and 30% by weight of glass fiber were mixed. The resulting mixtures were separately cold-pressed under a pressure of 80 Kg/cm ² and sintered at 320° C. for 2 hours. The tensile strengths of these reinforced fluoropolymer alloys at room temperature were 250, 220, and 150 Kg/cm ² , respectively. Example 16 A fluoropolymer alloy made from 50 g of EHMW-FEP and 50 g of PTFE was mixed with 20% by weight of glass fiber and also 30% by weight of graphite, and the resulting mixture was ground to pass through a 40 mesh sieve. , cold compressed under a pressure of 80Kg/ ^cm2 , then
Sintering was performed at 320°C for 2 hours. The tensile strength, elongation and hardness (Rockwell) of the reinforced fluoropolymer alloy were 150 Kg/cm ² , 220% and 58, respectively. Synthesis Example An example of a method for producing an ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer will be shown. A stainless steel autoclave with a capacity of 130 kg was charged with 45 kg of starting monomer containing 60 kg of deionized water and 86.6% by weight of hexafluoropropylene. 55-57 under the pressure of 22.0Kg/ ^cm2
℃, then 25 ml of diisopropyl percarbonate was added and copolymerization was carried out for 3 hours. Contains 14.5% by weight of hexafluoropropylene, 1.8
Dry copolymer powder with melt viscosity of ×10 ⁶ poise and melt flow index of 0.3 g/10 min
7.5Kg was obtained. 310 samples of copolymer powder
It was molded into a 2 mm thick sheet at ℃. This sheet is
Tensile strength 290Kg/cm ² , elongation 320%, 2x at room temperature
It showed a flexural fatigue life of more than 10 ⁵ cycles.

Claims (1)

[Claims] 1 (A) Weight average molecular weight of 2×10 ⁵ or more, 1×10 ⁶
A melt-processable ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer having a melt viscosity of ≥0.8 g/10 min, a melt flow index of ≤0.8 g/10 min, and a hexafluoropropylene content of 12 to 30% by weight. 0.1～
99.9% by weight, (B) polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride,
Tetrafluoroethylene-ethylene copolymer,
Co-pulverization of dry powder and wet powder comprising 99.9 to 0.1% by weight of at least one polymer selected from the group consisting of polysulfone, polyethylene, polypropylene, polyimide, polycarbonate, polyphenylene oxide and polyphenylene sulfide. A fluoropolymer alloy characterized in that it is a powder blend manufactured by. 2. The fluoropolymer alloy according to claim 1, comprising an ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer and polytetrafluoroethylene. 3 0.1 to 60% by weight of ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer and
99.9 to 40% by weight of polytetrafluoroethylene. 4. The fluoropolymer alloy according to any one of claims 1 to 3, to which glass fiber, graphite, molybdenum disulfide, carbon, or metal powder is added. 5. The fluoropolymer alloy according to claim 1, which is a co-milled product of either a dry powder or a wet powder. 6. Claims 1 or 5 processed by melt pressing, cold pressing and sintering, powder coating, fluidized bed powder coating, or ram extrusion of a paste consisting of dry powder and a wetting agent. The fluoropolymer alloy described. 7. The fluoropolymer alloy according to claim 6, which is melt-compressed at a temperature of 300 to 350°C and a pressure of 50 to 200 Kg/cm ² . 8 Cold compressed under pressure of 50~200Kg/ ^cm2 , 300~
The fluoropolymer alloy according to claim 6, which is sintered at a temperature of 390 degrees. 9. Fluoropolymer alloy according to claim 6, in which petroleum ether or kerosene is used as a wetting agent during ram extrusion of a paste consisting of a dry powder and a wetting agent. 10 Various diaphragms, various sealing materials, various lined valves, various lined pipes, various lined pumps,
Claims 1 to 4 can be processed into various products exhibiting excellent thermal stability, chemical inertness, and remarkable electrical insulation properties, including corrosion-resistant pump bodies and impellers, and wound and coated wires. The fluoropolymer alloy according to any one of the above. 11 (A) Weight average molecular weight of 2×10 ⁵ or more, 1×
10 Melt processable ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer having a melt viscosity of ⁶ poise or more, a melt flow index of 0.8 grams/10 minutes or less, and a hexafluoropropylene content of 12 to 30% by weight. a polymer; (B) polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride;
Tetrafluoroethylene-ethylene copolymer,
At least one polymer selected from the group consisting of polyethylene, polypropylene, polysulfone, polyimide, polycarbonate, polyphenylene oxide, and polyphenylene sulfide is separately ground, and then the polymers are mixed in a predetermined weight ratio of 40 A method for producing a fluoropolymer alloy by co-pulverization of dry powder, characterized by mixing the fluoropolymer alloy while pulverizing it homogeneously until it passes through a mesh sieve. 12 (A) Weight average molecular weight of 2×10 ⁵ or more, 1×
10 Melt processable ultra-high molecular weight tetrafluoroethylene-hexafluoropropylene copolymer having a melt viscosity of ⁶ poise or more, a melt flow index of 0.8 grams/10 minutes or less, and a hexafluoropropylene content of 12 to 30% by weight. a polymer; (B) polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride;
Tetrafluoroethylene-ethylene copolymer,
At least one polymer selected from the group consisting of polyethylene, polypropylene, polysulfone, polyimide, polycarbonate, polyphenylene oxide, and polyphenylene sulfide is moistened with water, ethyl alcohol, ethyl acetate, or a mixed solvent thereof. A method for producing a fluoropolymer alloy by wet powder co-pulverization, characterized in that the fluoropolymer alloy is then ground until homogeneous, filtered, and dried to obtain a product that can finally pass through a 40-mesh sieve.