CN114274640A - Rapid-curing high-flame-retardant mica prepreg, mica plate and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of fireproof materials. The invention provides a fast-curing high-flame-retardant mica prepreg which comprises the following components in percentage by mass of 50-80: 10-30: 10-40 parts of mica paper, an epoxy resin composition and a reinforcing material; the epoxy resin composition comprises the following components in a mass ratio of 100: 2-18: 12-40 of epoxy resin, a curing agent and an additive. The invention also provides a preparation method of the fast curing high-flame-retardant mica prepreg and a method for preparing a mica plate by using the prepreg. The prepreg is quickly cured at 150 ℃, and the curing time is 3-5 min; the glass transition temperature of the mica plate reaches above 130 ℃, the flame retardant property can reach the V0 level of vertical burning, the tensile strength reaches above 160MPa, the bending strength reaches above 180MPa, and after burning for 3min at 1500 ℃, the retention rate of the tensile strength reaches above 45%.

Description

A kind of fast curing high flame retardant mica prepreg and its mica board and preparation method

technical field

The invention relates to the technical field of fireproof materials, in particular to a fast-curing high-flame-retardant mica prepreg, a mica board and a preparation method thereof.

Background technique

Mica material has the advantages of non-toxic, tasteless, high temperature resistance, high pressure resistance, aging resistance, corrosion resistance, good insulation performance, etc. It is widely used in household appliances, wires and cables and new energy vehicle battery packs. The mica material used in the field of new energy vehicles is to impregnate the mica paper with a silicone-based adhesive, mold the mica board at high temperature, and assemble it between the battery core and the battery upper cover to realize the fireproof function. Although this mica board has good fire resistance, the silicone adhesive used in this process needs to be cured at a temperature above 200 ° C for 20 to 30 minutes. The curing temperature is high, the curing time is long, the production efficiency is low, and the energy consumption is low. At the same time, because the mica plate is assembled between the cell and the upper cover of the battery, it occupies a large space and the assembly cost is high.

The prior art discloses a resin composite insulating mica paper and a preparation method thereof. The mica paper also uses an epoxy resin adhesive, but this resin does not have flame retardant properties, and needs to be kept at a temperature of 120-130° C. Curing 30 ~ 45min, can not be cured quickly. The prior art also discloses a high temperature resistant and flame retardant mica tape. The adhesive used in the mica tape is Y-type high-temperature adhesive or SAR-8 methyl silicone resin, which can be used for a long time at 400° C. It does not burn and only emits smoke, but the resin needs to be cured at a temperature above 200 ° C, and the curing time is not less than 20 minutes. It also has the defects of high curing temperature and long curing time.

Therefore, it is of great value and significance to research and develop a mica prepreg with low curing temperature and short curing time for the preparation of mica boards with excellent fire-retardant properties, mechanical strength and modulus.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of fast curing high flame retardant mica prepreg and its mica plate and preparation method aiming at the deficiencies of the prior art.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides a fast-curing high flame-retardant mica prepreg, comprising the following preparation raw materials: mica paper, an epoxy resin composition and a reinforcing material;

The mass ratio of the mica paper, the epoxy resin composition and the reinforcing material is 50-80:10-30:10-40;

The epoxy resin composition comprises epoxy resin, curing agent and additives; the mass ratio of the epoxy resin, curing agent and additives is 100:2-18:12-40.

Preferably, the mica paper includes one or more of phlogopite mica paper, muscovite paper, calcined mica paper and synthetic mica paper; the mica paper has a grammage of 100-300 g/m ² ; the reinforcing material Contains one or more of carbon fiber fabrics, carbon fiber mats, glass fiber fabrics and glass fiber mats.

Preferably, the epoxy resin comprises one or more of flame-retardant brominated epoxy resin, bisphenol A epoxy resin, novolac epoxy resin and bisphenol F epoxy resin; the curing agent Contains one or more of dicyandiamide curing agent, modified imidazole curing agent and modified urea curing agent; the additive includes one or more of carbon black paste, internal mold release agent and inorganic flame retardant several.

Preferably, the inorganic flame retardant comprises one or more of aluminum hydroxide, magnesium hydroxide, zinc borate, antimony oxide and molybdenum oxide.

Preferably, when the curing agent comprises a dicyandiamide curing agent, a modified imidazole curing agent and a modified urea curing agent, the dicyandiamide curing agent, the modified imidazole curing agent and the modified urea curing agent are cured The mass ratio of the additive is 1-5:1-5:1-5; when the additive comprises carbon black paste, internal mold release agent and inorganic flame retardant, the carbon black paste, internal mold release agent and inorganic flame retardant The mass ratio of the fuel is 1-3:0.5-2.5:15-30.

Preferably, the carbon black paste comprises bisphenol F epoxy resin, carbon black and a dispersant; the mass ratio of the bisphenol F epoxy resin, carbon black and dispersant is 100:12～25:3～ 10; the particle size of the carbon black slurry is less than or equal to 5 μm.

Preferably, the structure of the prepreg from top to bottom is a reinforcing material layer, an epoxy resin film, a mica layer, an epoxy resin film, and a reinforcing material layer.

The present invention also provides a method for preparing the fast-curing high-flame-retardant mica prepreg, comprising the following steps:

1) coating the epoxy resin composition to obtain an epoxy resin film;

2) impregnating the epoxy resin film and mica paper to obtain a composite layer;

3) compounding the composite layer and the reinforcing fiber to obtain a fast curing high flame retardant mica prepreg;

Step 1) the coating temperature is 65～85℃, and the line speed is 9～15m/min;

Step 2) The temperature of the impregnation is 95-125° C., and the line speed is 3-7 m/min.

The invention also provides a method for preparing a mica board from the fast-curing high-flame-retardant mica prepreg.

The curing temperature is 140-160° C., the pressure is 0.55-0.85 MPa, and the time is 3-5 minutes.

The present invention also provides a mica plate obtained by the preparation method.

The beneficial effects of the present invention include the following points:

1) The fast-curing and high-flame-retardant mica prepreg of the present invention is rapidly cured at 150° C., and the curing time is 3 to 5 minutes.

2) The glass transition temperature of the mica board prepared by the fast-curing and highly flame-retardant mica prepreg of the present invention reaches above 130° C., the flame retardant performance can reach the V0 level of vertical combustion, the tensile strength can reach above 160 MPa, and the bending strength can reach above 180 MPa , the compressive strength reaches more than 125MPa, and the tensile strength retention rate reaches more than 45% after burning at 1500 ℃ for 3 minutes.

3) The epoxy resin composition of the present invention has good flame retardant properties, can be rapidly cured at medium temperature, and can be co-cured with the epoxy resin prepreg for the upper cover of the battery box molded by molding. The preparation of the battery box cover with the fire-resistant mica layer can not only reduce the manufacturing cost, but also release more space for the battery core material, thereby effectively improving the energy volume density of the battery pack.

Detailed ways

The invention provides a fast-curing high flame-retardant mica prepreg, comprising the following preparation raw materials: mica paper, an epoxy resin composition and a reinforcing material;

The mass ratio of the mica paper, the epoxy resin composition and the reinforcing material is 50-80:10-30:10-40;

The epoxy resin composition comprises epoxy resin, curing agent and additives; the mass ratio of the epoxy resin, curing agent and additives is 100:2-18:12-40.

The mass ratio of the mica paper, the epoxy resin composition and the reinforcing material in the present invention is preferably 55-75: 15-25: 15-35, more preferably 60-70: 18-22: 20-30, more preferably 63-66:20:23-25.

The mica paper of the present invention preferably comprises one or more of phlogopite mica paper, muscovite paper, calcined mica paper and synthetic mica paper; more preferably phlogopite mica paper; when the mica paper contains several components at the same time, each The components are preferably combined in an equal mass ratio; the grammage of the mica paper is preferably 100-300 g/m ² , more preferably 150-230 g/m ² , more preferably 180-200 g/m ² .

The mica paper of the invention does not contain any binder, does not affect the curing speed of the epoxy resin, has good temperature resistance and high gram weight, and can meet the strength requirements of the impregnation process in the production process of the prepreg.

The mica prepreg of the invention has high mica content and low epoxy resin content, and effectively improves the temperature resistance of the mica prepreg.

The reinforcing material of the present invention preferably comprises one or more of carbon fiber fabrics, carbon fiber mats, glass fiber fabrics and glass fiber mats; when the reinforcing material contains several components at the same time, each component is preferably mixed in an equal mass ratio .

The epoxy resin composition of the present invention preferably comprises an epoxy resin, a curing agent and an additive; the mass ratio of the epoxy resin, the curing agent and the additive is preferably 100:3.5-15:16.5-35, more preferably 100: 5 to 12: 18 to 30, more preferably 100: 7 to 10: 20 to 25.

The epoxy resin of the present invention preferably comprises one or more of flame-retardant brominated epoxy resin, bisphenol A epoxy resin, novolac epoxy resin and bisphenol F epoxy resin; When several components are included at the same time, each component is preferably mixed in an equal mass ratio.

The curing agent of the present invention preferably includes one or more of a dicyandiamide curing agent, a modified imidazole curing agent and a modified urea curing agent; when the curing agent simultaneously includes a dicyandiamide curing agent, a modified imidazole curing agent In the case of a curing agent and a modified urea curing agent, the mass ratio of the dicyandiamide curing agent, the modified imidazole curing agent and the modified urea curing agent is preferably 1-5:1-5:1-5, and further It is preferably 2 to 4:2 to 4:2 to 4; when the curing agent contains two components at the same time, they are preferably mixed in an equal mass ratio.

The modified imidazole curing agent of the present invention preferably comprises 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methyl One or more of base imidazole and 1-cyanoethyl-2-isopropylimidazole; the modified urea curing agent preferably includes one or more of DyhardUR200, DyhardUR300 and DyhardUR500.

The additive of the present invention preferably comprises one or more of carbon black paste, internal mold release agent and inorganic flame retardant; when the additive contains carbon black paste, internal mold release agent and inorganic flame retardant at the same time, the carbon black paste, internal mold release agent and inorganic flame retardant The mass ratio of black paste, internal mold release agent and inorganic flame retardant is preferably 1-3:0.5-2.5:15-30, more preferably 1.5-2.5:1-2:18-25, more preferably 2:1.5 : 20 to 22; when the additive contains two components at the same time, it is preferable to mix them in an equal mass ratio.

The inorganic flame retardant of the present invention preferably contains one or more of aluminum hydroxide, magnesium hydroxide, zinc borate, antimony oxide and molybdenum oxide; when the inorganic flame retardant contains several components at the same time, each component The mixing is preferably carried out in an equal mass ratio.

The carbon black paste of the present invention preferably comprises bisphenol F type epoxy resin, carbon black and dispersant; the mass ratio of the bisphenol F type epoxy resin, carbon black and dispersant is preferably 100:12～25:3 ~10, more preferably 100:16~22:5~8, more preferably 100:18~20:6~7; the particle size of the carbon black slurry is preferably ≤5μm, more preferably 2.5~4.5μm, more preferably 3～4μm.

The dispersant of the present invention is preferably BYK-W980, BYK-9076, DISPERBYK-2013 or DISPERBYK-2150.

The carbon black slurry of the present invention is preferably ground and dispersed uniformly by a three-roll mill or a high-speed dispersant.

The internal mold release agent of the present invention is preferably a mixed solution containing synthetic resin, glycerides, organic acid derivatives and organic phosphate copolymers, more preferably internal mold release agent INT-1890.

The structure of the prepreg of the present invention is, from top to bottom, a reinforcing material layer, an epoxy resin film, a mica layer, an epoxy resin film, and a reinforcing material layer.

The present invention also provides a method for preparing the fast-curing high-flame-retardant mica prepreg, comprising the following steps:

1) coating the epoxy resin composition to obtain an epoxy resin film;

2) impregnating the epoxy resin film and mica paper to obtain a composite layer;

3) compounding the composite layer and the reinforcing fiber to obtain a fast curing high flame retardant mica prepreg;

Step 1) the coating temperature is 65～85℃, and the line speed is 9～15m/min;

Step 2) The temperature of the impregnation is 95-125° C., and the line speed is 3-7 m/min.

The temperature of the coating in step 1) of the present invention is preferably 70-80°C, more preferably 73-77°C, more preferably 75°C; the linear speed of the coating is preferably 10-14m/min, more preferably 11 to 13 m/min, more preferably 12 m/min.

The coating in step 1) of the present invention is preferably carried out on release paper; the release paper is used as a protective material.

The temperature of the impregnation in step 2) of the present invention is preferably 100-120°C, more preferably 105-115°C, and more preferably 110°C; the line speed of the impregnation is preferably 4-6 m/min, more preferably 4.5- 5.5 m/min, more preferably 5 m/min.

The impregnation process of the fast-curing high flame-retardant mica prepreg of the present invention includes coating film and impregnation, and is a two-step hot-melt impregnation process. The fast-curing and high-flame-retardant mica prepreg of the present invention is preferably wrapped with a polyethylene film, and rolled and packaged; the polyethylene film is used as a protective material.

The invention also provides a method for preparing a mica board from the fast-curing high-flame-retardant mica prepreg.

The curing temperature is 140-160° C., the pressure is 0.55-0.85 MPa, and the time is 3-5 minutes.

The curing temperature of the present invention is preferably 145-155°C, more preferably 147-152°C, more preferably 149-150°C; the curing pressure is preferably 0.6-0.8MPa, more preferably 0.65-0.75 MPa, more preferably 0.7MPa; the curing time is preferably 3.5-4.5min, more preferably 4min.

The present invention also provides a mica plate obtained by the preparation method.

The technical solutions provided by the present invention will be described in detail below with reference to the examples, but they should not be construed as limiting the protection scope of the present invention.

Example 1

Epoxy resin, curing agent and additives with a mass ratio of 100:3:15 were formulated into an epoxy resin composition. The epoxy resin includes flame-retardant brominated epoxy resin, bisphenol A epoxy resin and phenolic epoxy resin with a mass ratio of 30:22.6:27.4. The curing agent includes dicyandiamide curing agent, 1-benzyl-2-methylimidazole curing agent and DyhardUR200 curing agent in a mass ratio of 1.2:1.0:0.8. The additives included carbon black paste (4 μm in particle size) with a mass ratio of 1.2:0.8:15, internal mold release agent INT-1890 and zinc borate. The carbon black paste contains bisphenol F-type epoxy resin, carbon black and dispersant BYK-W980 in a mass ratio of 100:18:6.

The epoxy resin composition was heated to 70°C on a film coating machine, and the film was coated on release paper at a line speed of 10 m/min to obtain an epoxy resin film.

210g muscovite paper (gram weight is 210g/m ² ) and 36g epoxy resin film are impregnated, the temperature of impregnation is 100°C, and the line speed is 4m/min to obtain a mica layer in the middle and epoxy resin on the upper and lower sides. Composite layers of membranes. The carbon fiber felt is compounded on the upper and lower sides of the composite layer, and the carbon fiber felt has a gram weight of 54 g to obtain a fast-curing high flame-retardant mica prepreg. Finally, the polyethylene film is coated on the fast curing high flame retardant mica prepreg, and it is rolled and packaged.

Example 2

Epoxy resin, curing agent and additives in a mass ratio of 100:12:30 were formulated into an epoxy resin composition. Wherein, the epoxy resin includes bisphenol A type epoxy resin, bisphenol F type epoxy resin and novolac epoxy resin with a mass ratio of 30:25:50. The curing agent includes a dicyandiamide curing agent and a 1-cyanoethyl-2-methylimidazole curing agent in a mass ratio of 2:1. The additives included carbon black paste (4.5 μm particle size), aluminum hydroxide and antimony oxide in a mass ratio of 2:13:13. The carbon black paste contains bisphenol F-type epoxy resin, carbon black and dispersant BYK-9076 in a mass ratio of 100:23:8.

The epoxy resin composition was heated to 82° C. on a film coating machine, and the film was coated on release paper at a line speed of 14 m/min to obtain an epoxy resin film.

Compound impregnation of 180g of phlogopite paper (weight 180g/m ² ) and 45g of epoxy resin film, the impregnation temperature is 120°C, and the line speed is 6m/min, to obtain a mica layer in the middle and epoxy resin on the upper and lower sides. Composite layers of membranes. The carbon fiber felt is compounded on the upper and lower sides of the composite layer, and the carbon fiber felt has a gram weight of 45 g to obtain a fast-curing high flame-retardant mica prepreg. Finally, the polyethylene film is coated on the fast curing high flame retardant mica prepreg, and it is rolled and packaged.

Example 3

Epoxy resin, curing agent and additives with a mass ratio of 100:9:23 were formulated into an epoxy resin composition. The epoxy resin includes flame-retardant brominated epoxy resin and bisphenol F-type epoxy resin with a mass ratio of 40:25. The curing agent includes dicyandiamide curing agent, 1-cyanoethyl-2-ethyl-4-methylimidazole curing agent and DyhardUR500 curing agent in a mass ratio of 1:1:1. The additives include carbon black paste (particle size is 3.5μm) with a mass ratio of 2:1:18, internal mold release agent INT-1890 and inorganic flame retardant (inorganic flame retardant is composed of equal mass of magnesium hydroxide and zinc borate) ). The carbon black paste contains bisphenol F-type epoxy resin, carbon black and dispersant DISPERBYK-2150 in a mass ratio of 100:20:6.

The epoxy resin composition was heated to 75° C. on a film coating machine, and the film was coated on release paper at a line speed of 12 m/min to obtain an epoxy resin film.

Compound impregnation of 195g of phlogopite paper (weight 195g/m ² ) and 30g of epoxy resin film, the impregnation temperature is 110°C, and the line speed is 5m/min, to obtain a mica layer in the middle and epoxy resin on the upper and lower sides. Composite layers of membranes. The upper and lower sides of the composite layer are compounded with glass fiber mats, and the mass of the glass fiber mats is 45 g to obtain a fast curing high flame retardant mica prepreg. Finally, the polyethylene film is coated on the fast curing high flame retardant mica prepreg, and it is rolled and packaged.

The resin contents of the fast-curing and high-flame-retardant mica prepregs of Examples 1 to 3 are 20.4%, 25.0%, and 17.4%, respectively.

The fast-curing and high-flame-retardant mica prepreg of Example 1 was laid together, and was cured and molded in a hot press. The curing and molding temperature was 150° C., the pressure was 0.7 MPa, and the time was 4 minutes to obtain a mica board.

Using the same curing conditions as in Example 1, the fast-curing and highly flame-retardant mica prepregs of Example 2 and Example 3 were respectively cured and molded to obtain mica boards.

The performance test results of the mica boards of Examples 1-3 are shown in Table 1, wherein the test method of fire resistance is to test the tensile strength retention rate of the mica boards after burning at 1500° C. for 3 minutes.

Table 1 The performance test results of mica boards of Examples 1-3

As can be seen from Table 1, the mica prepreg of the present invention has excellent fire resistance and flame retardant properties, and can be rapidly cured, and the mica plate obtained after curing and molding has excellent tensile strength, bending strength and compressive strength. High, tensile modulus, flexural modulus and compression modulus are high.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. a fast curing high flame retardant mica prepreg, is characterized in that, comprises following preparation raw material: mica paper, epoxy resin composition and reinforcing material; The mass ratio of the mica paper, the epoxy resin composition and the reinforcing material is 50-80:10-30:10-40; The epoxy resin composition comprises epoxy resin, curing agent and additives; the mass ratio of the epoxy resin, curing agent and additives is 100:2-18:12-40. 2. prepreg material according to claim 1, is characterized in that, described mica paper comprises one or more in phlogopite mica paper, muscovite paper, calcined mica paper and synthetic mica paper; The grammage is 100-300 g/m ² ; the reinforcing material includes one or more of carbon fiber fabrics, carbon fiber mats, glass fiber fabrics and glass fiber mats. 3. The prepreg according to claim 1 or 2, wherein the epoxy resin comprises flame retardant brominated epoxy resin, bisphenol A epoxy resin, novolac epoxy resin and bisphenol F One or more of epoxy resins; the curing agent includes one or more of dicyandiamide curing agent, modified imidazole curing agent and modified urea curing agent; the additive includes carbon black One or more of slurry, internal mold release agent and inorganic flame retardant. 4. The prepreg according to claim 3, wherein the inorganic flame retardant comprises one or more of aluminum hydroxide, magnesium hydroxide, zinc borate, antimony oxide and molybdenum oxide. 5. The prepreg according to claim 3, wherein when the curing agent comprises a dicyandiamide curing agent, a modified imidazole curing agent and a modified urea curing agent, the dicyandiamide curing agent The mass ratio of the agent, the modified imidazole curing agent and the modified urea curing agent is 1-5:1-5:1-5; when the additives include carbon black paste, internal mold release agent and inorganic flame retardant and the mass ratio of the carbon black slurry, the internal mold release agent and the inorganic flame retardant is 1-3:0.5-2.5:15-30. 6. The prepreg according to claim 4 or 5, wherein the carbon black paste comprises bisphenol F type epoxy resin, carbon black and a dispersant; the bisphenol F type epoxy resin, carbon black The mass ratio of black and dispersant is 100:12-25:3-10; the particle size of the carbon black slurry is less than or equal to 5 μm. 7 . The prepreg according to claim 6 , wherein the structure of the prepreg from top to bottom is a reinforcing material layer, an epoxy resin film, a mica layer, an epoxy resin film, and a reinforcing material layer. 8 . 8. The preparation method of the fast-curing high flame-retardant mica prepreg according to any one of claims 1 to 7, characterized in that, comprising the following steps: 1) coating the epoxy resin composition to obtain an epoxy resin film; 2) impregnating the epoxy resin film and mica paper to obtain a composite layer; 3) compounding the composite layer and the reinforcing fiber to obtain a fast curing high flame retardant mica prepreg; Step 1) the coating temperature is 65～85℃, and the line speed is 9～15m/min; Step 2) The temperature of the impregnation is 95-125° C., and the line speed is 3-7 m/min. 9. The method for preparing a mica board using the fast-curing high-flame-retardant mica prepreg described in any one of claims 1 to 7, wherein the fast-curing high-flame-retardant mica prepreg is cured and molded to obtain a mica board ; The curing temperature is 140-160° C., the pressure is 0.55-0.85 MPa, and the time is 3-5 minutes. 10. The mica plate obtained by the preparation method of claim 9.