A low-gum mica tape and a method for manufacturing the same

Abstract

The application discloses a little-gum mica tape which is composed of a reinforcing material layer, a first adhesive layer, a mica paper layer and a second adhesive layer arranged in sequence, and a preparation method thereof. The reinforcing material is pulled through a mica tape machine, the first adhesive is coated on the surface of the reinforcing material, the mica paper is wound and combined with the reinforcing material after pre-baking, the combined material is baked in an oven, then the second adhesive is coated or sprayed on the surface of the mica paper to obtain a semi-finished product, and the semi-finished product is formed after baking in the oven, and the little-gum mica tape is prepared by winding and cutting. The application adds LNBR-820 to improve the poor adhesion between the mica tape layers and the problem that the mica paper and the reinforcing material are prone to delamination. The surface treatment is performed on the side of the mica paper which is not reinforced to solve the problem that the mica paper is prone to flying powder and falling off during the production and use, and the processability of the little-gum mica tape is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of insulating materials, and particularly relates to a little-gum mica tape and a preparation method thereof. BACKGROUND

[0002] With the increase of the single-machine capacity of the generator and the increase of the rated voltage, higher requirements are continuously put forward for the mica tape insulating material in the insulating industry. The little-gum mica tape has better compatibility with the insulating impregnated resin, higher electrical insulation performance, and obvious overall performance advantages, and gradually becomes the future development trend of mica insulating materials. The insulating structure taking the little-gum mica tape as the main body and using the VPI continuous insulating technology can provide good insulating performance for the motor.

[0003] Due to the low gum content of the little-gum mica tape, less adhesive is left between the reinforcing material and the mica paper, which leads to poor adhesion between the mica tape layers and easily causes the delamination of the mica paper and the reinforcing material, which will result in poor wrapping process performance, and affect the insulating performance and use effect.

[0004] And the mica paper flake made by the mechanical method with the white mica which has not been calcined as the raw material has large flake and the flake is not tightly combined with each other, so it is easy to fly off and fall off in the production and use of the mica tape. SUMMARY

[0005] One of the purposes of the present application is to overcome the deficiencies of the little-gum mica tape described in the background art. A little-gum mica tape is provided, which adds an appropriate amount of LNBR-820 to the base resin of the first adhesive, and simultaneously uses the second adhesive to treat the surface of the mica paper to solve the above problems.

[0006] The technical scheme adopted by the present application to solve its technical problems is: a little-gum mica tape, which is composed of a reinforcing material layer, a first adhesive layer, a mica paper layer, and a second adhesive layer arranged in sequence; the adhesive formula of the first adhesive layer (referred to as the first adhesive) includes heat-resistant solid phenolic epoxy resin, liquid heat-resistant bisphenol A type epoxy resin, amino resin, LNBR-820, and latent curing agent in a mass ratio of 12:8:2:1-2.4:0.2; the adhesive formula of the second adhesive layer (referred to as the second adhesive) includes heat-resistant solid phenolic epoxy resin, amino resin, and latent curing agent in a mass ratio of 10:10:0.1.

[0007] The little-gum mica tape uses one or more of toluene, xylene, and acetone as the solvent in the first adhesive, and uses methylal as the solvent in the second adhesive.

[0008] The little-gum mica tape uses polyester film with a thickness of 0.025 mm±0.0025 mm as the reinforcing material, and the quantitative polyester film is 35 g / m2 ±3g / m 2 .

[0009] The mica paper of the low-glue mica tape is made of uncalcined muscovite pulped by mechanical method, and the basis weight of the mica paper is 160g / m 2 ±3g / m 2 , thickness is 0.105mm±0.008mm.

[0010] The low-glue mica tape has a first adhesive layer with an adhesive content of 3% to 7%, and a second adhesive layer with an adhesive content of 1% to 3%.

[0011] The LNBR-820 of the low-rubber mica tape is a commercially available liquid nitrile rubber.

[0012] The amino resin of the low-resistance mica tape is 625 resin.

[0013] The second object of the present invention is to provide a method for preparing a low-glue mica tape, which comprises the following steps: (1) pulling a reinforcing material through a mica tape machine and applying a first adhesive to the surface of the reinforcing material; (2) compounding the unwound mica paper with the reinforcing material after pre-baking; (3) baking the compounded material in a first stage oven; (4) then coating or spraying a second adhesive on the surface of the mica paper to obtain a semi-finished product; (5) baking the surface-treated semi-finished product in two stages of ovens and then forming the semi-finished product; and (6) winding and slitting the semi-finished product to obtain a finished product.

[0014] In the method for preparing a low-resistance mica tape, the pre-baking temperature in step (2) is 80°C±3°C.

[0015] In the method for preparing a low-glue mica tape, in step (3), the mica paper and the reinforcing material are compounded and then baked in an oven at a temperature of 60°C±3°C.

[0016] In the method for preparing a low-resistance mica tape, in step (5), the surface-treated semi-finished product is baked in two ovens at temperatures of 60°C ± 3°C and 50°C ± 3°C, respectively, and then formed.

[0017] In the method for preparing the low-resistance mica tape, the baking time during the production process is 5 minutes to 10 minutes.

[0018] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0019] The present application enhances the interlayer adhesion of the mica tape, improves the delamination of the mica paper and the reinforcing material, and improves the process of the low-gum mica tape wrapping by adding appropriate LNBR-820 to the base resin of the first adhesive of the low-gum mica tape. In addition, the present application uses the adhesive to perform surface treatment on the mica paper, so that the mica tape does not fly powder and does not fall off during the production process and the wrapping process. Embodiment

[0020] The present application will be described more fully with the following specific examples. The following examples are only used to illustrate the basic situation and experimental process of the present application, and do not represent that the present application is limited by the experimental conditions of the following examples, and the experimental conditions in all examples can be adjusted according to different use requirements.

[0021] The reinforcing material, adhesive raw material, mica paper and production equipment involved in the present application can be purchased. Example 1

[0022] The preparation method of the low-gum mica tape in this embodiment is as follows.

[0023] The reinforcing material is pulled through the mica tape machine, and the first adhesive is coated on the surface of the reinforcing material. After pre-baking, the unwound mica paper is compounded with the reinforcing material. The compounded material is baked through a section of oven. Then the second adhesive is coated or sprayed on the surface of the mica paper to obtain a semi-finished product. The surface-treated semi-finished product is further baked through two sections of oven to form a finished product. The finished product is obtained by winding and cutting. The pre-baking temperature is 80℃±3℃, the baking temperature of the mica paper after compounding with the reinforcing material is 60℃±3℃, the baking temperature of the mica paper after surface treatment is 60℃±3℃ and 50℃±3℃ respectively, and the baking time during production is 5min-10min.

[0024] In this embodiment, the polyester film has a basis weight of 35g / m 2 ±3g / m 2 , a thickness of 0.025mm±0.0025mm, and a first adhesive layer content of 5%; the mica paper has a basis weight of 160g / m 2 ±3g / m 2 , a thickness of 0.105mm±0.008mm, and a second adhesive layer content of 2%.

[0025] The formula of the first adhesive includes heat-resistant solid phenolic epoxy resin, liquid heat-resistant bisphenol A type epoxy resin, amino resin, LNBR-820 and latent curing agent in a mass ratio of 12:8:2:1:0.2. The solvent used in the first adhesive is one or more of toluene, xylene and acetone.

[0026] The second adhesive is formulated with heat-resistant solid phenolic epoxy resin, amino resin and latent curing agent in a mass ratio of 10:10:0.1. The solvent used in the second adhesive is methylal.

[0027] The above low-gum mica tape, due to the good adhesion and good compatibility of LNBR-820 with the epoxy resin, the adhesive compounded with the epoxy resin has stronger bonding force than the existing adhesive with only epoxy resin as the base resin. By adding an appropriate amount of LNBR-820 to the base resin of the adhesive (referred to as the first adhesive) of the first adhesive layer of the low-gum mica tape, the interlayer bonding force of the mica tape is enhanced, and the poor adhesion between the mica tape layers and the easy delamination of the mica paper and the reinforcing material due to the low gum content of the low-gum mica tape and the small amount of adhesive left between the reinforcing material and the mica paper are improved. The second adhesive layer (referred to as the second adhesive) is used to treat the surface of the side of the mica paper that is not reinforced, to solve the problem of easy powder flying and falling off during production and use, and to improve the processability of the low-gum mica tape. Example 2

[0028] The low-gum mica tape is prepared by the same preparation process as in Example 1, except that the first adhesive is formulated with heat-resistant solid phenolic epoxy resin, liquid heat-resistant bisphenol A type epoxy resin, 625 resin, LNBR-820 and latent curing agent in a mass ratio of 12:8:2:1.2:0.2. Example 3

[0029] The low-gum mica tape is prepared by the same preparation process as in Example 1, except that the first adhesive is formulated with heat-resistant solid phenolic epoxy resin, liquid heat-resistant bisphenol A type epoxy resin, 625 resin, LNBR-820 and latent curing agent in a mass ratio of 12:8:2:1.4:0.2. Example 4

[0030] The low-gum mica tape is prepared by the same preparation process as in Example 1, except that the first adhesive is formulated with heat-resistant solid phenolic epoxy resin, liquid heat-resistant bisphenol A type epoxy resin, 625 resin, LNBR-820 and latent curing agent in a mass ratio of 12:8:2:1.6:0.2. Example 5

[0031] The low-gum mica tape is prepared by the same preparation process as in Example 1, except that the first adhesive is formulated with heat-resistant solid phenolic epoxy resin, liquid heat-resistant bisphenol A type epoxy resin, 625 resin, LNBR-820 and latent curing agent in a mass ratio of 12:8:2:1.8:0.2. Example 6

[0032] A low-gum mica tape was prepared in the same preparation process as Example 1, except that the formulation of the first adhesive layer included a heat-resistant solid phenolic epoxy resin, a liquid heat-resistant bisphenol A type epoxy resin, 625 resin, LNBR-820, and a latent curing agent in a mass ratio of 12:8:2:2:0.2. Example 7

[0033] A low-gum mica tape was prepared in the same preparation process as Example 1, except that the formulation of the first adhesive layer included a heat-resistant solid phenolic epoxy resin, a liquid heat-resistant bisphenol A type epoxy resin, 625 resin, LNBR-820, and a latent curing agent in a mass ratio of 12:8:2:2.2:0.2. Example 8

[0034] A low-gum mica tape was prepared in the same preparation process as Example 1, except that the formulation of the first adhesive layer included a heat-resistant solid phenolic epoxy resin, a liquid heat-resistant bisphenol A type epoxy resin, 625 resin, LNBR-820, and a latent curing agent in a mass ratio of 12:8:2:2.4:0.2. Example 9

[0035] A low-gum mica tape was prepared in the same preparation process as Example 1, except that the first adhesive layer had a gum content of 3% and the second adhesive layer had a gum content of 1%. Example 10

[0036] A low-gum mica tape was prepared in the same preparation process as Example 1, except that the first adhesive layer had a gum content of 7% and the second adhesive layer had a gum content of 3%.

[0037] Comparative Example 1

[0038] A low-gum mica tape was prepared in the same preparation process as Example 1, except that:

[0039] The formulation of the first adhesive layer included a heat-resistant solid phenolic epoxy resin, a liquid heat-resistant bisphenol A type epoxy resin, 625 resin, and a latent curing agent in a mass ratio of 12:8:2:0.2.

[0040] Comparative Example 2

[0041] A low-gum mica tape was prepared in the same preparation process as Example 1, except that:

[0042] The surface of the mica paper, which was not reinforced, was not treated with an adhesive.

[0043] The few-gum mica tapes prepared from Examples 1-10 and Comparative Example 1 were subjected to interlayer bonding strength test and comparison; the appearance of the un-reinforced side of the few-gum mica tapes prepared from Examples 1-10 and Comparative Examples 1 and 2 was observed, and the results are shown in the following table:

[0044]

[0045] From the above table, it can be seen from the interlayer bonding strength test results of the few-gum mica tapes prepared according to Examples 1-8 and Comparative Example 1 that, when the same preparation process as Example 1 is used to prepare the few-gum mica tape, and the formulation of the first adhesive is changed to include heat-resistant solid phenolic epoxy resin, liquid heat-resistant bisphenol A type epoxy resin, 625 resin, LNBR-820, and latent curing agent in a mass ratio of 12:8:2:2:0.2, the interlayer bonding strength of the few-gum mica tape is the largest, and the adhesion effect of the reinforcing material to the mica paper is better than that of other examples. From the interlayer bonding strength test results of the few-gum mica tapes prepared according to Example 6 and Examples 9 and 10, it can be seen that the adhesive content of the few-gum mica tape also affects the adhesion effect between the reinforcing material and the mica paper, and the greater the adhesive content, the better the adhesion effect.

[0046] From the observation of the appearance of the un-reinforced side of the few-gum mica tapes prepared according to any one of Examples 1-10 and Comparative Example 2, it can be seen that the mica paper surface of the examples subjected to surface treatment by the adhesive does not fly powder or fall off.

[0047] The above examples only exemplarily illustrate the principles and effects of the present application, and part of the employed examples, and those skilled in the art can make several modifications and improvements without departing from the inventive concept, which are all within the protection scope of the present application.

Claims

1. A low-resistance mica tape, characterized by: The invention is composed of a reinforcing material layer, a first adhesive layer, a mica paper layer, and a second adhesive layer arranged in sequence; the adhesive formula of the first adhesive layer includes heat-resistant solid phenolic epoxy resin, liquid heat-resistant bisphenol A epoxy resin, amino resin, LNBR-820 and latent curing agent in a mass ratio of 12:8:2:1 to 2.4:0.2; the adhesive formula of the second adhesive layer includes heat-resistant solid phenolic epoxy resin, liquid heat-resistant bisphenol A epoxy resin, amino resin, LNBR-820 and latent curing agent in a mass ratio of 10: 10:0.1 heat-resistant solid phenolic epoxy resin, amino resin and latent curing agent.

2. The low-resistance mica tape according to claim 1, characterized in that: The solvent used in the first adhesive is one or more of toluene, xylene, and acetone, and the solvent used in the second adhesive is methylal.

3. The low-resistance mica tape according to claim 1, characterized in that: The reinforcing material is a polyester film with a thickness of 0.025mm±0.0025mm, and the basis weight of the polyester film is 35 / m 2 ±3g / m 2 .

4. The low-resistance mica tape according to claim 1, characterized in that: The mica paper is made of uncalcined muscovite pulped by mechanical method, and the basis weight of the mica paper is 160g / m 2 ±3g / m 2 , thickness is 0.105mm±0.008mm.

5. The low-resistance mica tape according to claim 1, characterized in that: The adhesive content of the first adhesive layer is 3% to 7%, and the adhesive content of the second adhesive layer is 1% to 3%.

6. The low-resistance mica tape according to claim 1, characterized in that: The LNBR-820 is liquid nitrile rubber.

7. The low-resistance mica tape according to claim 1, characterized in that: The amino resin is 625 resin.

8. A method for preparing the low-resistance mica tape as claimed in claim 1, characterized in that: The steps are: (1) Pull the reinforcing material onto the mica tape machine and apply the first adhesive to the surface of the reinforcing material; (2) After pre-baking, the unrolled mica paper is compounded with the reinforcing material; (3) The composite material is baked in an oven; (4) Then, the second adhesive is coated or sprayed on the surface of the mica paper to obtain a semi-finished product; (5) The semi-finished product after surface treatment is baked in two stages of oven and then formed; (6) Rolling and cutting to make finished products.

9. The method for preparing a low-resistance mica tape according to claim 8, characterized in that: The pre-baking temperature in step (2) is 80°C ± 3°C.

10. The method for preparing a low-resistance mica tape according to claim 8, characterized in that: In the step (3), the mica paper and the reinforcing material are compounded and then baked in an oven at a temperature of 60°C ± 3°C.

11. The method for preparing a low-resistance mica tape according to claim 8, characterized in that: In the step (5), the surface-treated semi-finished product is baked in two ovens at temperatures of 60°C ± 3°C and 50°C ± 3°C respectively and then formed.

12. The method for preparing a low-resistance mica tape according to claim 8, characterized in that: The baking time in the production process is 5 minutes to 10 minutes.

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