TWI748469B - A mixed aqueous dispersion for heat-resistant impregnation agent, coating agent or paint being formed by polyimide-fluorine resin, a mixed powder for molding material being formed by polyimide-fluorine resin, and a method for producing thereof - Google Patents

Abstract

The invention provides a polyimide-fluorine resin mixed aqueous dispersion and a mixed powder, and a method for producing thereof, that has excellent handling properties (safety, environmental load, equipment costs, etc.) and excellent adhesion and heat resistance performance, even without using an organic solvent. The polyimide-fluorine resin mixed aqueous dispersion and the polyimide-fluorine resin mixed powder according to the present invention contain a polyimide, a fluorine containing resin, an alumina, and a potassium persulfate.

Description

Mixed aqueous dispersion for heat-resistant impregnant, coating agent or paint composed of fluorine-containing polyimide resin, mixed powder for molding material composed of fluorine-containing polyimide resin, and manufacturing method thereof

The present invention relates to a fluorine-containing polyimide resin mixed aqueous dispersion and mixed powder and a manufacturing method thereof. In more detail, the present invention relates to a fluorine-containing polyimide resin blend that has excellent operability (safety, environmental load, equipment cost, etc.), excellent adhesion and heat resistance even without the use of organic solvents Aqueous dispersion liquid and mixed powder produced by the dispersion liquid and its production method.

In the prior art, a mixture of polyimide and PTFE (polytetrafluoroethylene) and other fluorine-containing resins is known; because the mixture has a low coefficient of friction, it has excellent properties such as non-adhesion, chemical resistance, and heat resistance. It is widely used in the surface processing of food industry products, kitchen appliances such as pans or pots, irons and other household products, electrical industry products, and machinery industry products.

For example, Patent Document 1 discloses a polyimide precursor solution composition in which the dispersion state of a fluorine-containing resin is uniformly controlled, and lists the heat resistance, mechanical properties, and low dielectric constant obtained from the composition. , Polyimide and polyimide film with excellent electronic material properties and processability such as low dielectric loss tangent, and manufacturing method thereof, and circuit board and cover film using the polyimide film.

More specifically, the characteristics of the polyimide precursor solution composition of the fluorine-containing resin are disclosed, which are characterized in that at least the non-aqueous dispersion of the fluorine-containing resin, the polyimide precursor solution, and the non-aqueous dispersion of the fluorine-containing resin are disclosed. The aqueous dispersion contains ultrafine powder of fluorine-containing resin and fluorine-based additives containing at least fluorine-containing groups and lipophilic groups. The water content of the non-aqueous dispersion of fluorine-containing resin measured by Karl Fischer method is below 5000ppm .

According to Patent Document 1, a polyimide precursor solution composition in which the dispersion state of a fluorine-containing resin is uniformly controlled, and the heat resistance, mechanical properties, sliding properties, insulation properties, and low dielectric constant obtained from the composition are provided Polyimide and polyimide film with excellent processability, such as electronic material characteristics such as low dielectric loss tangent, and excellent processability, and their production methods, as well as circuit boards using the polyimide and polyimide film, Covering films, insulating films, related insulating films for wiring boards, surface protective layers, sliding layers, peeling layers, fibers, filter materials, wire covering materials, bearings, paints, insulation shafts, trays, seamless belts, etc. Various belts, belts, catheters, etc.

[Patent Document 1] Japanese Patent Publication No. 2016-210886

As described above, in the past, a mixture of polyimide and fluorine-containing resin has been used for various applications such as coating agents. However, the conventional mixture, as described in Patent Document 1, for example, uses an organic solvent as a solvent in order to uniformly disperse the mixture of polyimide and fluorine-containing resin. Because of the use of organic solvents, there are problems with the operability (safety, environmental load, equipment cost) of the mixture. Therefore, there is a need for a mixed aqueous dispersion of polyimide and fluorine-containing resin that does not use an organic solvent and is excellent in operability.

The present invention was completed in order to solve the above-mentioned problems of the prior art. It provides an aqueous fluorine-containing polyimide resin mixed dispersion that has excellent bonding performance and heat resistance even without the use of organic solvents, and is manufactured from the dispersion Of mixed powders, and their manufacturing methods.

The present invention relates to a fluorine-containing polyimide resin mixed aqueous dispersion as described in claim 1, which is characterized by comprising: polyimide, fluorine-containing resin, alumina, and potassium persulfate.

The present invention relates to the mixed aqueous dispersion according to claim 1 described in claim 2, characterized in that it further contains PVA (polyvinyl alcohol).

The present invention relates to the mixed aqueous dispersion according to claim 1 or 2 described in claim 3, which is characterized in that it further contains phosphoric acid.

The present invention relates to a mixed aqueous dispersion according to any one of claims 1 to 3 described in claim 4, wherein the fluorine-containing resin is a polymer of monomers selected from the following materials Or fluorine-containing resin particles composed of copolymers: tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro(alkyl vinyl ether), vinylidene fluoride, vinyl fluoride.

The present invention relates to a fluorine-containing polyimide resin mixed powder as described in claim 5, which is characterized by comprising: polyimide, fluorine-containing resin, alumina, and potassium persulfate.

The present invention relates to the mixed powder according to claim 5 described in claim 6, characterized in that it further contains PVA (polyvinyl alcohol).

The present invention relates to the mixed powder according to claim 5 or 6 described in claim 7, which is characterized in that it further contains phosphoric acid.

The present invention relates to the mixed powder according to any one of claims 5 to 7 described in claim 8, wherein the fluorine-containing resin is a polymer or copolymer of monomers selected from the following materials: Fluorine-containing resin particles composed of materials: tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride, vinyl fluoride.

The present invention relates to a method for producing a fluorine-containing polyimide resin mixed aqueous dispersion as described in claim 9, and is characterized in that it includes the step of adding potassium persulfate to water to prepare a potassium persulfate aqueous solution; And the step of mixing polyimide, fluorine-containing resin, alumina and the aforementioned potassium persulfate aqueous solution.

The present invention relates to the manufacturing method according to claim 9 described in claim 10, wherein the polyimide is a polyimide-phosphoric acid powder that is dried after being mixed with a phosphoric acid ethanol solution. Mix the powder.

The present invention relates to the manufacturing method according to claim 9 or 10 as described in claim 11, characterized in that the fluorine-containing resin is composed of a polymer or copolymer of monomers selected from the following substances The fluorine-containing resin particles: tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride, vinyl fluoride.

The present invention relates to a method for producing a fluorine-containing polyimide resin mixed powder as described in claim 12, which is characterized in that it includes: The polyimide resin is mixed with an aqueous dispersion and dried.

According to claim 1, since the fluorine-containing polyimide resin mixed aqueous dispersion of the present invention contains polyimide, fluorine-containing resin, alumina and potassium persulfate, it can provide polyimide and fluorine-containing resin uniformly Dispersed aqueous mixed dispersion. In addition, due to the fluorine-containing polyimide The resin mixed aqueous dispersion contains alumina and potassium persulfate, so that a dispersion with excellent adhesion and heat resistance can be obtained. Therefore, even without using an organic solvent, a fluorine-containing polyimide resin mixed aqueous dispersion with excellent coating characteristics can be obtained. Furthermore, since the fluorine-containing polyimide resin mixed aqueous dispersion does not contain an organic solvent, it has excellent operability (safety, environmental load, equipment cost, etc.).

According to claim 2, since the fluorinated polyimide resin mixed aqueous dispersion of the present invention further contains PVA (polyvinyl alcohol), a fluorinated polyimide resin mixed aqueous dispersion having more excellent coating properties can be obtained.

According to claim 3, since the fluorinated polyimide resin mixed aqueous dispersion of the present invention further contains phosphoric acid, it is possible to obtain a fluorinated polyimide resin mixed aqueous dispersion with better dispersibility and coating characteristics.

According to claim 4, the fluorine-containing resin of the present invention is a fluorine-containing resin particle composed of a polymer or copolymer of a monomer selected from the following substances: tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene , Perfluoro (alkyl vinyl ether), vinylidene fluoride, vinyl fluoride, so that a fluorine-containing polyimide resin mixed aqueous dispersion with better coating characteristics can be obtained.

According to claim 5, since the fluorine-containing polyimide resin mixed powder of the present invention contains polyimide, fluorine-containing resin, alumina and potassium persulfate, it is possible to provide a uniformly mixed polyimide and fluorine-containing resin , And can be used as a molding material for a variety of products such as high heat-resistant products. In addition, since the fluorine-containing polyimide resin mixed powder contains alumina and potassium persulfate, a mixed powder with excellent heat resistance, processability, and moldability can be obtained.

According to claim 6, since the fluorine-containing polyimide resin mixed powder of the present invention further contains PVA, it is possible to obtain a mixed powder with more excellent processability and moldability.

According to claim 7, since the fluorine-containing polyimide resin mixed powder of the present invention further contains phosphoric acid, it is possible to obtain a mixed powder that is more uniformly mixed and has more excellent processability and moldability.

According to claim 8, because the fluorine-containing resin of the present invention is a fluorine-containing resin particle composed of a polymer or copolymer of a monomer selected from the following substances: tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene , Perfluoro (alkyl vinyl ether), vinylidene fluoride, vinyl fluoride, so you can get a mixed powder with more excellent heat resistance, processability and moldability.

According to claim 9, the method for producing a fluorine-containing polyimide resin mixed aqueous dispersion of the present invention includes: adding potassium persulfate to water to prepare a potassium persulfate aqueous solution, and adding polyimide, fluorine The resin, alumina, and the aforementioned potassium persulfate aqueous solution are mixed to produce an aqueous mixed dispersion in which the polyimide and the fluorine-containing resin are uniformly dispersed. In addition, in addition to polyimide and fluorine-containing resin, it also includes a step of mixing alumina and potassium persulfate, so that a dispersion with excellent adhesion and heat resistance can be manufactured. Therefore, even without using an organic solvent, it is possible to produce a fluorine-containing polyimide resin mixed aqueous dispersion with excellent coating characteristics and excellent operability.

According to claim 10, since the polyimide of the present invention is a polyimide-phosphoric acid mixed powder that is dried to form a powder after being mixed with a phosphoric acid ethanol solution, the dispersibility to an aqueous solution containing no organic solvent can be improved , And can produce a fluorine-containing polyimide resin mixed aqueous dispersion with better dispersibility and better coating characteristics.

According to claim 11, because the fluorine-containing resin of the present invention is a fluorine-containing resin particle composed of a polymer or copolymer of a monomer selected from the following substances: tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene , Perfluoro (alkyl vinyl ether), vinylidene fluoride, vinyl fluoride, so it is possible to produce a fluorine-containing polyimide resin mixed aqueous dispersion with better coating characteristics.

According to claim 12, the method for producing the fluorine-containing polyimide resin mixed powder of the present invention includes: mixing the fluorine-containing polyimide resin produced by the manufacturing method described in any one of claims 9 to 11 with an aqueous dispersion The liquid is dried, so that the polyimide and the fluorine-containing resin are uniformly mixed and can be used as a molding material for a variety of products such as high heat-resistant products.

Fig. 1 is a graph showing the results of a checkerboard test of the fluorine-containing polyimide resin mixed with an aqueous dispersion of the present invention.

Fig. 2 is a graph showing the results of a checkerboard test using a fluorine-containing polyimide resin mixed with an aqueous dispersion liquid of a comparative example.

The following describes a suitable embodiment of the fluorine-containing polyimide resin mixed aqueous dispersion of the present invention (hereinafter, simply referred to as mixed aqueous dispersion).

The mixed aqueous dispersion contains polyimide, fluorine-containing resin, alumina, and potassium persulfate. In addition, the mixed aqueous dispersion may further contain PVA and/or phosphoric acid.

Polyimine (PI) is a resin composed of a polymer having an imine bond in its molecular structure. The polyimide used in the mixed aqueous dispersion is not particularly limited. For example, resins composed of high-molecular-weight polymers obtained by the reaction of aromatic tetravalent acid anhydrides such as pyromellitic anhydride can also be used. Any polyimide known to those skilled in the art. In addition, the polyimide used in the mixed aqueous dispersion may be crushed and recovered from the used polyimide, or it may be unused. The shape of the polyimide is not particularly limited, but from the viewpoint that it is easy to maintain a floating and dispersed state in the mixed aqueous dispersion for a long time, it is suitable for fine particles with a particle size in the range of 1 μm to 100 μm. The polyimide is relative to the mixed water The content of the dispersion is suitably 10% by weight to 40% by weight, and 15% by weight to 30% by weight is more suitable.

The fluorine-containing resin used in the mixed aqueous dispersion is not particularly limited. For example, fluorine-containing resin particles composed of polymers or copolymers selected from the following materials: tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoroethylene (Alkyl vinyl ether), vinylidene fluoride, vinyl fluoride. The above-mentioned substances are dispersed in water for the preparation of mixed aqueous dispersions. The shape of the fluorine-containing resin is not particularly limited, but from the viewpoint that it is easy to maintain a floating and dispersed state in the mixed aqueous dispersion for a long time, it is a fine particle with an average molecular weight in the range of 1×10 ⁴ to 1×10 ⁷ . The size is suitable in the range of 100~500nm. The content of the fluorine-containing resin (solid content of the fluorine-containing resin) relative to the mixed aqueous dispersion is suitably 20% by weight to 60% by weight, and more suitably 30% by weight to 50% by weight.

As mentioned above, the fluorine-containing resin used in the mixed aqueous dispersion is not particularly limited. For example, it can be used, A-1: POLYFLON (registered trademark of Daikin) D-111 (PTFE solid content: 60 Weight %, average molecular weight: 2×10 ⁴ to 1×10 ⁷ , particle size: 0.25 μm, pH: 9.7); A-2: manufactured by Asahi Glass Co., Ltd., AD911E (PTFE solid content: 60% by weight, average molecular weight: 2×10 ⁴ ~1×10 ⁷ , particle size: 0.25 μm, pH: 10); A-3: manufactured by Mitsui Fluorochemical Co., 31-JR (PTFE solid content: 60% by weight, average molecular weight: 2× 10 ⁴ ~1×10 ⁷ , particle size: 0.25 μm, pH: 10.5), etc. In addition, the particle size refers to the average particle diameter of the PTFE primary particles.

The mixed aqueous dispersion contains alumina. The alumina in the present invention includes: alumina [composition formula: Al ₂ O ₃ ], amorphous aluminum hydroxide, gibbsite, bay gibbsite [composition formula: Al(OH) ₃ ], and/or Aluminum oxide particles of boehmite and diaspore [composition formula: AlOOH]. From the viewpoint that it is easy to maintain the floating dispersion state for a long time in the mixed aqueous dispersion, the particle size of the alumina particles is preferably in the range of 5 to 4500 nm. The content of alumina relative to the mixed aqueous dispersion is preferably 1% by weight to 10% by weight, and more preferably 3% by weight to 7% by weight. This is because if the content of alumina is less than 1% by weight, the adhesive and heat resistance properties that should be produced by alumina cannot be sufficiently brought to the mixed aqueous dispersion, but more than 10% by weight cannot be expected. The effect is better than the effect of the above content. By including alumina in the mixed aqueous dispersion, a mixed aqueous dispersion with excellent adhesion and heat resistance can be obtained.

In addition, the shape of the alumina of the alumina sol is not particularly limited, and may be any shape such as a plate shape, a columnar shape, a fiber shape, and a hexagonal plate shape. When the alumina sol is fibrous, it will exhibit fibrous crystals of alumina. More specifically, alumina fibers formed from anhydrous alumina, hydrated alumina fibers formed from alumina containing hydrates, and the like can be cited.

The alumina used for mixing the aqueous dispersion is not particularly limited. Alumina sol-10A (Al ₂ O ₃ converted weight %: 9.8~10.2, particle size nm: 5~15, viscosity 25°C, mPa/s ：<50, pH: 3.4~4.2, manufactured by Chuanyan Fine Chemicals Co., Ltd.); Alumina sol-A2 (Al ₂ O ₃ conversion weight %: 9.8~10.2, particle size nm: 10~20, viscosity 25°C, MPa /s: <200, pH: 3.4~4.2, manufactured by Chuanyan Fine Chemicals Co., Ltd.); alumina sol-CSA-110AD (Al ₂ O ₃ conversion weight %: 6.0~6.4, particle size nm: 5~15, Viscosity 25°C, mPa/s: <50, pH: 3.8~4.5, manufactured by Chuanyan Fine Chemicals Co., Ltd.; Alumina sol-F1000 (Al ₂ O ₃ conversion weight %: 4.8~5.2, particle size nm: 1400 , Viscosity 25℃, mPa/s: <1000, pH: 2.9~3.3, manufactured by Chuanyan Fine Chemicals Co., Ltd.; Alumina sol-F3000 (Al ₂ O ₃ conversion weight %: 4.8~5.2, particle size nm: 2000 ~4500, viscosity 25°C, mPa/s: <1000, pH: 2.7~3.3, manufactured by Chuanyan Fine Chemicals Co., Ltd., etc. Any alumina sol known to those skilled in the art can be used.

As described above, the alumina used for mixing the aqueous dispersion is not particularly limited, but it is suitable to use fine particles of alumina having a hydroxyl group (OH group). By using an OH group Alumina, the chemical bonding force (bonding force) generated by the OH group of alumina will increase, so it can bring more excellent bonding performance to the mixed aqueous dispersion.

In addition, as an alternative to or in addition to alumina, other metal oxide particles may be added. Other metal oxide fine particles are not particularly limited, and titanium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide, tin oxide, or the like can be used. By adding these metal oxide fine particles as an alternative to alumina or in addition to alumina, a polyimide fluorine-containing resin mixed aqueous dispersion can be produced having coating characteristics different from the case where only alumina is added.

The mixed aqueous dispersion contains potassium persulfate. Since potassium persulfate is a compound containing OH groups, it can increase the number of OH groups contained in the mixed aqueous dispersion, and the chemical binding force (adhesive force) generated by the OH groups will also increase, so it can be mixed Aqueous dispersion brings excellent adhesion. The content of potassium persulfate relative to the mixed aqueous dispersion is suitably 0.1% by weight to 5% by weight, and more suitably 1% by weight to 3% by weight. This is because if the potassium persulfate content is less than 0.1% by weight, the mixed aqueous dispersion cannot sufficiently bring about the cohesiveness that should be produced by potassium sulfate, but it cannot be expected to bring more than the above-mentioned effect if it exceeds 5% by weight. The effect of the content is better.

In addition, as an alternative to potassium persulfate or in addition to potassium sulfate, other compounds containing OH groups can be added. Other OH group-containing compounds are not particularly limited, and acetic acid, benzoic acid, phenylphosphonic acid, benzoic acid, or the like can be used.

The mixed aqueous dispersion may further contain PVA (polyvinyl alcohol). PVA has the structural formula shown below and contains many OH groups. Therefore, the number of OH groups contained in the mixed aqueous dispersion can be increased, and the chemical bonding force (adhesive force) generated by the OH groups can also be increased, so that the mixed aqueous dispersion can bring excellent adhesion to the mixed aqueous dispersion. In addition, even if PVA is mixed into the mixed aqueous dispersion, it still exists stably in the mixed aqueous dispersion, and there is almost no possibility of reducing its adhesiveness. Therefore, the excellent adhesion performance of the mixed aqueous dispersion can be stably maintained for a long period of time. The content of the PVA with respect to the mixed aqueous dispersion is suitably 0.5% by weight to 10% by weight, and 3% by weight to 6% by weight is more suitable. This is because if the content of PVA is less than 0.5%, it will not be able to sufficiently bring about the adhesion properties that should be produced by PVA to the mixed aqueous dispersion, but more than 10% by weight cannot be expected to bring more effects than the above content. Better results.

The mixed aqueous dispersion may further contain phosphoric acid. Since phosphoric acid is a compound containing OH groups, it can increase the number of OH groups contained in the mixed aqueous dispersion, and the chemical binding force (bonding force) generated by the OH groups will also increase, so it can be a mixed aqueous dispersion Brings excellent adhesion. The content of phosphoric acid relative to the mixed aqueous dispersion is preferably 0.1% by weight to 5% by weight, and more preferably 1% by weight to 3% by weight. This is because if the content of phosphoric acid is less than 0.1% by weight, the mixed aqueous dispersion cannot sufficiently bring about the adhesion properties that should be produced by phosphoric acid, but it cannot be expected to bring more than the above-mentioned content if it exceeds 5% by weight. The effect is better.

Phosphoric acid can also be used for the pretreatment of polyimide before it is added to the mixed aqueous dispersion. By adding polyimine to phosphoric acid-containing phosphoethanol and mixing, and then evaporating the ethanol, a polyimine-phosphoric acid mixed powder can be obtained. Compared with polyimide monomers, polyimine-phosphoric acid mixed powder can be dispersed in an aqueous solvent more easily.

In addition, in addition to the above-mentioned constituent elements, the mixed aqueous dispersion may also contain other additives and the like to change the properties of the mixed aqueous dispersion. As an additive, for example, Solvents, binder boiling water, plasticizers, hardeners, crosslinking agents, diluents, fillers, thickeners, pigments, etc., but not limited to these, they are usually used to change the properties of mixed aqueous dispersions and are useful to those skilled in the art. Any additives known to the personnel can be used.

Hereinafter, the manufacturing method of the mixed aqueous dispersion liquid is demonstrated.

The manufacturing method of the mixed aqueous dispersion includes the following steps: adding potassium persulfate to water to prepare a potassium persulfate aqueous solution; mixing polyimide, fluorine-containing resin, alumina, and the above potassium persulfate aqueous solution. The manufacturing method of the mixed aqueous dispersion may further include a pretreatment step, including: mixing the polyimide and the phosphoric acid ethanol solution, and then drying it to prepare the polyimide-phosphoric acid mixed powder. In addition, in these steps, the mixing method, mixing temperature, and mixing time are not particularly limited, and any conventionally used mixing method capable of producing a mixed aqueous dispersion can be used.

The potassium persulfate aqueous solution is prepared by adding potassium persulfate to water. More specifically, potassium persulfate is added to water so that the amount of potassium persulfate in the water is 1% by weight, and then the potassium persulfate is dissolved by heating to the extent that the water does not boil to prepare a potassium persulfate aqueous solution.

Polyimine is difficult to dissolve in aqueous solvents. Therefore, in order to improve the water dispersibility of the polyimide, it is more appropriate to pretreat the polyimide before preparing the mixed aqueous dispersion. The pretreatment step includes: mixing the polyimide and the phosphoric acid ethanol solution, and then drying the mixed solution and evaporating the water, thereby manufacturing the polyimide-phosphoric acid mixed powder. Compared with the case of using polyimide monomers, the use of polyimine-phosphoric acid mixed powder can greatly improve the water dispersibility of polyimine, making it easier to manufacture the mixed aqueous dispersion of the present invention. . In addition, even if the aforementioned pretreatment is not performed, the mixed aqueous dispersion related to the present invention can still be produced.

The prepared mixed aqueous dispersion liquid can obtain fluorine-containing polyimide resin mixed powder by evaporating water. Fluorine-containing polyimide resin mixed powder, polyimide and fluorine-containing resin It is uniformly mixed, and because it contains alumina and potassium persulfate that can bring excellent adhesion and heat resistance, it can be used as an excellent forming material for a wide range of products such as high heat resistance products.

The fluorine-containing polyimide resin mixed powder is produced by mixing the fluorine-containing polyimide resin of the present invention with an aqueous dispersion, drying, and evaporating water. In addition, the drying method for preparing the fluorine-containing polyimide resin mixed powder is not particularly limited, and any method that can evaporate the water of the fluorine-containing polyimide resin mixed aqueous dispersion of the present invention to obtain a powder can be used.

[Example]

Hereinafter, the present invention will be explained in more detail through examples, but the present invention is not limited to the listed examples.

<Checkerboard Test>

The performance of the aqueous dispersion of the present invention as a coating agent was confirmed by a checkerboard test. The structure and manufacturing method of the Example and the comparative example are as follows.

(Example)

The composition of the example is as follows. Polyimide powder (KAPTON (registered trademark) H type (manufactured by Toray-DuPont)): 20% by weight. PTFE dispersion (PTFE-D; manufactured by Daikin Industrial Co., Ltd.): 73.5% by weight. Alumina sol (Al-L7; manufactured by Taki Chemical Industry Co., Ltd.): 5 wt%. Potassium persulfate: 1% by weight. Phosphoric acid: 0.5% by weight.

The preparation of the examples is as follows.

1. Add polyimide powder powder to a 1% phosphoric acid ethanol solution (pH 5) and mix, and then evaporate water through an evaporator to prepare polyimide-phosphoric acid mixed powder.

2. Add potassium sulfate to pure water so that the amount of potassium persulfate is 1% by weight, and heat and dissolve potassium persulfate at 95° C. to prepare a potassium persulfate aqueous solution.

3. Mix the polyimide-phosphoric acid mixed powder, PTFE dispersion, alumina sol, and potassium persulfate aqueous solution to prepare an example (a fluorine-containing polyimide resin mixed aqueous dispersion).

(Comparative example)

The composition of the comparative example is as follows. Polyimide powder (KAPTON (registered trademark) H type (manufactured by Toray DuPont)): 20% by weight. PTFE dispersion (PTFE-D; manufactured by Daikin Industry Co., Ltd.): 75% by weight. Alumina sol (Al-L7; manufactured by Taki Chemical Industry Co., Ltd.): 5 wt%.

The preparation of the comparative example is as follows.

1. Mix polyimide powder, PTFE dispersion and alumina sol to make a comparative example.

(experiment method)

The checkerboard test is performed as follows.

1. Use a constant temperature shaker to stir the Examples and Comparative Examples at 60°C for 2 hours.

2. Use a coating bar to coat the stirred Examples and Comparative Examples on a 2mm×2mm aluminum plate (n=2, respectively) to prepare samples.

3. The samples were fired in the order of 30 minutes at 80°C, 30 minutes at 150°C, 60 minutes at 250°C, and 60 minutes at 350°C.

4. Using the fired sample, perform the checkerboard test (cross-cut method) specified in JIS K5600 5-6.

(test results)

Figures 1 to 2 show the results of the checkerboard test. Fig. 1 is a graph showing the result of a checkerboard test using the fluorine-containing polyimide resin of the present invention to mix an aqueous dispersion (Example). Fig. 2 is a graph showing the result of a checkerboard test using a fluorine-containing polyimide resin mixed with an aqueous dispersion liquid of a comparative example. As shown in Fig. 1, it can be seen that in the embodiment coated on the aluminum plate, the coating condition is good, and the coating film peels less, and has excellent adhesion. On the other hand, as shown in Fig. 2, it can be seen that the comparative example coated on the aluminum plate has a good coating condition, but most of the coating film on the aluminum plate will gradually peel off and the adhesion is low.

From the result of the checkerboard test, it can be known that the adhesion performance of the comparative example containing only polyimide, PTFE and alumina sol is very low, which is not practical. On the other hand, it can be seen that the examples containing polyimide, PTFE, alumina soluble, potassium persulfate and phosphoric acid have excellent adhesion properties. This is because potassium persulfate and phosphoric acid (especially potassium persulfate) increase the adhesion performance of the fluorine-containing polyimide resin mixed aqueous dispersion due to the effect of their OH groups.

〔Possibility of industrial use〕

Through the fluorine-containing polyimide resin mixed aqueous dispersion of the present invention, since the fluorine-containing polyimine resin mixed aqueous dispersion contains polyimide, fluorine-containing resin, alumina and potassium persulfate, it can provide polyimide Aqueous mixed dispersion in which imine and fluorine-containing resin are uniformly dispersed. In addition, since the fluorine-containing polyimide resin mixed aqueous dispersion contains alumina and potassium persulfate, a dispersion with excellent adhesion and heat resistance can be obtained. Therefore, even without using an organic solvent, a fluorine-containing polyimide resin mixed aqueous dispersion with excellent coating performance can be obtained. Furthermore, since the fluorine-containing polyimide resin mixed aqueous dispersion does not contain an organic solvent, it has excellent operability (safety, environmental load, equipment cost, etc.). Therefore, the fluorine-containing polyimide resin mixed aqueous dispersion of the present invention is suitable for use as heat-resistant coatings for pans, casseroles, frying pans, etc., knitwear, textiles, glass fiber cloth, carbon fiber, carbonized fiber, etc. The heat-resistant impregnation agent, as well as the coating agent or paint of various other products.

In addition, through the fluorine-containing polyimide resin mixed powder related to the present invention, since the fluorine-containing polyimide resin mixed powder contains polyimide, fluorine-containing resin, alumina and potassium persulfate, it is possible to provide polyimide Amine and fluorine-containing resin are uniformly mixed, and it is a molding material that can be widely used in products such as high heat-resistant products. In addition, since the fluorine-containing polyimide resin mixed powder contains alumina and potassium persulfate, a mixed powder with excellent heat resistance, processability, and moldability can be obtained. Therefore, the fluorine-containing polyimide resin mixed powder related to the present invention is suitable for use as a plastic film powder for bearings, friction materials, sliding bearings, anti-corrosion materials, insulating materials, etc., as well as various other high heat-resistant products.

Claims (7)

A mixed aqueous dispersion for heat-resistant impregnating agent, coating agent or paint composed of fluorine-containing polyimide resin, characterized in that it contains: polyimide, fluorine-containing resin, alumina, potassium persulfate, and Phosphoric acid. The mixed aqueous dispersion as described in claim 1, wherein the aforementioned fluorine-containing resin is fluorine-containing resin particles composed of a polymer or copolymer of a monomer selected from the following: tetrafluoroethylene, hexafluoropropylene , Trifluorochloroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride, vinyl fluoride. A mixed powder for molding materials composed of fluorine-containing polyimide resin, which is characterized by comprising: polyimide, fluorine-containing resin, alumina, potassium persulfate, and phosphoric acid. The mixed powder described in claim 3, wherein the aforementioned fluorine-containing resin is a fluorine-containing resin particle composed of a polymer or copolymer of a monomer selected from the following: tetrafluoroethylene, hexafluoropropylene, trifluoroethylene Chlorofluoroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride, vinyl fluoride. A method for manufacturing a heat-resistant impregnant, coating agent or a mixed aqueous dispersion for paint composed of fluorine-containing polyimide resin, which includes the step of adding potassium persulfate to water to prepare a potassium persulfate aqueous solution; And the step of mixing polyimide, fluorine-containing resin, aluminum oxide and the aforementioned potassium persulfate aqueous solution; wherein the aforementioned polyimine is: polyimide that is dried to form a powder after being mixed with a phosphoric acid ethanol solution- Phosphoric acid mixed powder. The manufacturing method described in claim 5, wherein the aforementioned fluorine-containing resin is a fluorine-containing resin particle composed of a polymer or copolymer of a monomer selected from the following: tetrafluoroethylene Ethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro(alkyl vinyl ether), vinylidene fluoride, vinyl fluoride. A method for producing a mixed powder for molding materials composed of a fluorine-containing polyimide resin, characterized in that it comprises a fluorine-containing polyimide resin produced by the method described in claim 5 or 6 The heat-resistant impregnant, coating agent, or mixed aqueous dispersion for coating is dried.

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