Composite insulation laminated board with high vertical layer direction bearing capacity and preparation method of composite insulation laminated board

Abstract

The invention provides a composite insulation laminated board with high vertical layer bearing capacity and a preparation method thereof, the composite insulation laminated board comprises an upper layer, a middle layer and a lower layer, the upper layer and the lower layer are respectively provided with 4-7 UPGM203 layers, the middle layer is formed by alternately overlapping one EPGC201 layer and 1-3 UPGM203 layers, and the total thickness of the laminated board is 130 + / -2mm. By optimizing the ratio of the resin paste, the fluidity and cohesiveness of the resin paste meet the lamination requirements; the EPGC201 prepreg with higher mechanical property and adhesive property is added and is staggered and overlapped with the UPGM203 prepreg for use, so that the vertical layer bearing capacity of the board is far greater than 10KN and reaches up to 2110KN; through the open type laminating equipment, under the condition of low initial temperature, high pressure is kept, pressure relief treatment is carried out under the condition of temperature rise, and finally high-temperature and high-pressure laminating is carried out, so that the phenomena of fiber extrusion and plate sliding of the plate are avoided; and finally, the 130 * 1000 * 1200 mm large-size composite laminated board is prepared, and the preparation method meets the batch production requirement.

Description

Technical Field

[0001] The present application belongs to the technical field of composite materials, and in particular relates to a composite insulating laminate with high vertical layer bearing capacity and a preparation method thereof. Background Art

[0002] UPGM 203 (GPO3) insulation board is made of unsaturated resin paste impregnated with alkali-free short-cut fiber mat to form a prepreg, and then the prepregs are stacked and hot-pressed by equipment to form a board. The existing laminate uses UPGM 203 parts with a size of 70*120*280mm, which is made by stacking prepregs to a thickness of 70mm and then processing them vertically; but due to the special use environment, under high-voltage electric fields, the copper bars installed on them have mutual repulsion, and the bearing force of the parts is parallel to the film layer, which will cause cracks and disconnections in the laminate. Summary of the invention

[0003] The present application is made in view of the above-mentioned problems, and its purpose is to provide a composite insulating laminate with high vertical layer bearing capacity and a preparation method thereof.

[0004] The first aspect of the present application provides a composite insulating laminate with high vertical layer bearing capacity, comprising an upper layer, a middle layer and a lower layer, wherein the upper layer and the lower layer are respectively provided with 4-7 UPGM203 layers, and the middle layer is formed by alternating 1 EPGC201 layer and 1-3 UPGM203 layers, and the total thickness of the laminate is 130±2mm.

[0005] In any embodiment, the single-piece specification of the UPGM203 layer is 2.0kg / pcs*1040*1250mm, and the single-piece specification of the EPGC201 layer is 0.56kg / pcs*1050*1260mm.

[0006] In any embodiment, the total weight of the laminate is 348 kg.

[0007] Under the process conditions of this application, the density fluctuation is small, and precise control of thickness can be achieved by controlling the weight.

[0008] The second aspect of the present application also provides a method for preparing a composite insulating laminate with high vertical layer bearing capacity, comprising the following steps:

[0009] First, 95-105 parts by weight of resin, 135-145 parts by weight of aluminum hydroxide filler, 4.5-5.5 parts by weight of polyethylene powder, 1.5-2.5 parts by weight of color paste, 1.1-1.5 parts by weight of release agent, 1.1-1.5 parts by weight of curing agent, 4.5-5.5 parts by weight of styrene (diluent), and 1.3-1.7 parts by weight of slow-release thickener are stirred in a reaction kettle to obtain a resin paste;

[0010] Secondly, the coiled alkali-free chopped fiber mat is impregnated with resin paste to make a prepreg, which is then cut into single prepregs of 1040*1250mm after thickening;

[0011] Furthermore, the prepreg is weighed and stacked to the required thickness in the form of 4-7 UPGM203 layers on the bottom layer, 1 EPGC201 layer and 1-3 UPGM203 layers on the middle layer, and 4-7 UPGM203 layers on the bottom layer;

[0012] Finally, the laminate is put through a laminator to control the temperature and pressure for hot pressing to obtain a laminate with a predetermined thickness.

[0013] In any embodiment, the impregnation amount of the coil is 650-750 g / ㎡.

[0014] The impregnation amount is the specification of the glass fiber substrate. This specification is used mainly to better control the fluidity and fiber content ratio. If the substrate weight is too high, the fibers in the middle of the substrate will not be fully impregnated, affecting the strength of the board. If the substrate weight is too low, the resin layer will be thinner under the same fiber content ratio, and the thickness of the resin layer is difficult to control, which will lead to deviation in the fiber content ratio.

[0015] In any embodiment, the temperature and pressure of the laminator are controlled as follows: the initial temperature is 25-35°C and the pressure is 160-240 bar; then the temperature is increased to 35-45°C, the pressure is 80-120 bar, and the heating rate is 1-2°C / min; the temperature is further increased to 140-150°C, the pressure is 220-240 bar, and the heating rate is 1-2°C / min.

[0016] The starting temperature is 25-35℃ and the pressure is 160-240bar to compact the material in advance so that the temperature at which the material is more fluid can be appropriately lowered to avoid sliding. The temperature rises later because the material begins to soften and its fluidity increases after heating. To avoid excessive glue flow, the pressure is reduced. As the material continues to heat up slowly, the pressure slowly increases to allow the layered structure to fully bond when it solidifies.

[0017] In any embodiment, the temperature and pressure of the laminator are controlled as follows: the starting temperature is 25-35°C, the pressure is maintained at 160-240 bar, when the temperature rises by 8-12°C, the pressure is released to 80-120 bar, and then the pressure is gradually increased to 230 bar. When the temperature of the surface material reaches 140-150°C, the intermediate temperature is 125-135°C, and heating is stopped.

[0018] After stopping heating, cool naturally while maintaining a pressure of 230 bar. After cooling to room temperature, remove the mold.

[0019] In any embodiment, the particle size of the aluminum hydroxide filler is 24 to 26 um.

[0020] The beneficial effects of the present invention are as follows: the present application optimizes the ratio of the resin paste so that its fluidity and adhesion meet the lamination requirements; and by adding EPGC201 semi-cured sheets with higher mechanical properties and adhesive properties, and staggeredly overlapping them with UPGM203 semi-cured sheets, the vertical layer bearing capacity of the board is much greater than 10KN, up to 23KN; the present application uses open lamination equipment to maintain a higher pressure under a lower starting temperature, and performs pressure relief treatment under heating, and finally performs high-temperature and high-pressure pressing, so that the board does not have fiber extrusion and sliding plate phenomena; finally, the preparation of large-size composite laminates of 130*1000*1200mm is achieved, and the preparation method meets the requirements of mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A physical picture of the product obtained by the method for preparing a composite insulating laminate with high vertical layer bearing capacity according to the present application.

[0022] Figure 2 A resin paste viscosity test chart obtained by a method for preparing a composite insulating laminate with high vertical layer bearing capacity in this application.

[0023] Figure 3 This is a bearing capacity test diagram of a composite insulating laminate with high vertical layer bearing capacity in this application. DETAILED DESCRIPTION

[0024] Hereinafter, the embodiments of the composite insulating laminate with high vertical layer bearing capacity and the method for preparing the same are specifically disclosed with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0025] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0026] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0027] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0028] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0029] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0030] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0031] The existing laminate uses UPGM 203 parts with a size of 70*120*280mm. It is made by stacking semi-cured sheets to a thickness of 70mm and then processing them vertically. When in use, the copper busbars are installed on the laminate. Under the condition of a high-voltage electric field, the copper busbars installed on it have a mutual repulsive effect, and the bearing force generated by the parts is parallel to the film layer, which will cause cracks and disconnection in the laminate.

[0032] In order to solve the above problems, the present application changes the processing direction of the plate, changing the vertical layer processing to parallel layer processing, so that the bearing force of the parts is perpendicular to the film layer, thereby improving the bearing force. However, the existing 70mm thick laminate cannot meet the processing requirements, and the thickness and size of the plate need to be increased for processing. The present application increases the size of the composite insulating laminate to 130*1000*1200mm and the thickness to 130±2mm. And through the optimization of the structural layer and process, the amount of glue discharge during the processing is reduced, the squeezing of the fiber slide plate is avoided, and the vertical layer bearing force and arc resistance are improved.

[0033] A composite insulating laminate with high vertical layer bearing capacity comprises an upper layer, a middle layer and a lower layer, wherein the upper layer and the lower layer are respectively provided with 4-7 UPGM203 layers, the middle layer is formed by alternatingly stacking 1 EPGC201 layer and 1-3 UPGM203 layers, and the total thickness of the laminate is 130±2mm.

[0034] In some embodiments, the single-piece specification of the UPGM203 layer is 2.0kg / pcs*1040*1250mm, and the single-piece specification of the EPGC201 layer is 0.56kg / pcs*1050*1260mm.

[0035] In some embodiments, the total weight of the laminate is 348 kg.

[0036] The second aspect of the present application also provides a method for preparing a composite insulating laminate with high vertical layer bearing capacity, comprising the following steps:

[0037] First, 95-105 parts by weight of resin, 135-145 parts by weight of aluminum hydroxide filler, 4.5-5.5 parts by weight of polyethylene powder, 1.5-2.5 parts by weight of color paste, 1.1-1.5 parts by weight of release agent, 1.1-1.5 parts by weight of curing agent, 4.5-5.5 parts by weight of styrene (diluent), and 1.3-1.7 parts by weight of slow-release thickener are stirred in a reaction kettle to obtain a resin paste;

[0038] The resin may be an unsaturated polyester resin, the color paste may be a monoazo type, the release agent may be a polyol phosphate, the curing agent may be tert-butyl peroxide, and the slow-release thickener may be magnesium oxide.

[0039] Secondly, the alkali-free chopped fiber mat in coil is impregnated with resin paste to make UPGM203 prepreg, which is then cut into single pressable prepregs of 1040*1250mm after thickening.

[0040] Furthermore, the prepreg is weighed and stacked to the required thickness in the form of 4-7 UPGM203 layers on the bottom layer, 1 EPGC201 layer and 1-3 UPGM203 layers on the middle layer, and 4-7 UPGM203 layers on the bottom layer;

[0041] Finally, the laminate is put through a laminator to control the temperature and pressure for hot pressing to obtain a laminate with a predetermined thickness.

[0042] In some embodiments, the impregnation amount of the coiled material is 650-750 g / ㎡.

[0043] In some embodiments, the temperature and pressure of the laminator are controlled as follows: the initial temperature is 25-35°C, the pressure is 160-240 bar; then it is increased to 35-45°C, the pressure is 80-120 bar, and the heating rate is 1-2°C / min; the temperature is continued to be increased to 140-150°C, the pressure is 220-240 bar, and the heating rate is 1-2°C / min.

[0044] In some embodiments, the temperature and pressure of the laminator are controlled as follows: the starting temperature is 25-35°C, the pressure is maintained at 160-240 bar, when the temperature rises by 8-12°C, the pressure is released to 80-120 bar, and then the pressure is gradually increased to 230 bar. When the temperature of the surface material reaches 140-150°C, the intermediate temperature is 125-135°C, and heating is stopped.

[0045] In some embodiments, the particle size of the aluminum hydroxide filler is 24 to 26 um.

[0046] Example

[0047] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0048] Example 1

[0049] A method for preparing a composite insulating laminate with high vertical layer bearing capacity comprises the following steps:

[0050] ① Preparation of resin paste: prepare the resin paste in a reaction kettle according to the following weight parts.

[0051] Raw material name Addition amount / kg / portion Resin 100 Alumina filler (H-WF-25) 140 Polyethylene powder 5.0 Color paste 2.0 Release agent 1.3 Curing agent 1.3 Styrene (diluent) 5.0 Slow-release thickener 1.5

[0052] ②Glass fiber impregnation

[0053] UPGM203 prepreg is made by impregnating 700g / ㎡*1040mm alkali-free chopped fiber felt in rolls, and then cut into single prepregs of 1040*1250mm after thickening. The weight of a single prepreg is about 2.0kg.

[0054] ③Weigh the overlapping materials

[0055] The UPGM203 prepreg (A) with a specification of 2.0kg / pcs*1040*1250mm and the EPGC201 prepreg (B) with a specification of 0.56kg / pcs*1050*1260mm are stacked in the form of 6 UPGM203 prepregs on the upper layer, 1 UPGM203 prepreg with 1 EPGC201 prepreg in the middle, and 6 UPGM203 prepregs on the lower layer, that is, the stacking method of 6A+AB*125+7A, with 138 A sheets and 125 B sheets, with a total weight of 348kg.

[0056] ④Hot pressing

[0057] In the laminator, hot pressing is completed in the following manner: the starting temperature is 30°C, the starting pressure is 200 bar, the heating temperature is 40°C, the heating pressure is 100 bar, the maximum temperature is 145°C, and the maximum pressure is 230 bar. That is, 200 bar is used to maintain the pressure in the initial stage, and when the temperature rises to 40°C, the pressure is released and exhausted, and then the pressure is gradually increased to 230 bar. When the temperature of the surface material reaches 145°C, the middle temperature is 130°C, and the heating is stopped.

[0058] Example 2

[0059] The difference from Example 1 is step 3. In Comparative Example 4, the overlapping method of the pressed plates is 6A+(1B3A)*50+4A, and the other steps and operations are the same as Example 1.

[0060] Comparative Example 1

[0061] The difference from Example 1 is that in step 1, the amount of alumina filler added in Comparative Example 1 is 120 parts by weight, and the other steps and operations are the same as Example 1.

[0062] Comparative Example 2

[0063] The difference from Example 1 is that in step 1, the amount of alumina filler added in Comparative Example 2 is 130 parts by weight, and the other steps and operations are the same as Example 1.

[0064] Comparative Example 3

[0065] The difference from Example 1 is that in step 1, the amount of alumina filler added in Comparative Example 3 is 150 parts by weight, and the other steps and operations are the same as Example 1.

[0066] The obtained laminate was tested, and the test results are shown in Table 1:

[0067] Table 1

[0068] Solution No. Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Viscosity / mPa.s 25050 14962 21270 30096 Is the film damaged? No No No have Extruded fiber skateboard Fiber extrusion Dislocation skateboard Severe fiber compression Slightly squeezed fibers

[0069] From the data in the above table, we know that in comparative example 3, there is less debonding during hot pressing, and the fiber extrusion is relatively mild, but the viscosity is high, and when preparing the semi-cured sheet during the impregnation process, the film is damaged and the production is not smooth. The films of Example 1 and Comparative Examples 1 and 2 are intact during the impregnation process and can smoothly prepare the semi-cured sheet, but the viscosity of the resin paste in Comparative Examples 1 and 2 is too low and the fluidity is high, resulting in a large amount of debonding of the board, with obvious fiber extrusion and sliding plate; although the board of Example 1 also has a large amount of debonding, the fiber extrusion is relatively mild, and there is no sliding plate.

[0070] Comparative Example 4

[0071] The difference from Example 1 is step 3. In Comparative Example 4, the overlapping method of the pressed plates is 4A+(1B6A)*26+6A, and the other steps and operations are the same as Example 1.

[0072] The obtained laminate was tested, and the test results are shown in Table 2:

[0073] Table 2

[0074] Solution No. Example 1 Example 2 Comparative Example 4 Extruded fiber skateboard No No Slightly squeezed fibers Vertical layer bearing capacity / KN 23 13 9 Arc resistance / S 203 189 196

[0075] Since the glass cloth of EPGC201 is a twisted textile thread, divided into warp and weft, arranged perpendicularly to each other, it has stronger mechanical properties; while the fiber mat of UPGM203 is just a uniformly scattered fiber; epoxy resin has better bonding properties than unsaturated resin. Comparative Example 4 adds EPGC201 prepreg and uses it in a mixed manner, and the fiber extrusion is significantly reduced; when more sheets are added to Example 1 and Example 2, there is no fiber extrusion and slide plate, and the vertical layer bearing capacity has a doubling effect. The bearing capacity of Example 1 and Example 2 exceeds 10KN, but the amount of EPGC201 prepreg is large and the cost is high.

[0076] Comparative Example 5

[0077] The difference from Example 1 is step 4. In Example 4, the starting temperature is 30°C, the starting pressure is 50 bar, the heating temperature is 40°C, the heating pressure is 70 bar, the maximum temperature is 145°C, and the maximum pressure is 230 bar. The other steps are the same as those of Example 1.

[0078] Comparative Example 6

[0079] The difference from Example 1 is step 4. In Example 4, the starting temperature is 30°C, the starting pressure is 50 bar, the heating temperature is 40°C, the heating pressure is 100 bar, the maximum temperature is 145°C, and the maximum pressure is 230 bar. The other steps are the same as other operations are the same as Example 1.

[0080] Comparative Example 7

[0081] The difference from Example 1 is step 4. In Example 4, the starting temperature is 30°C, the starting pressure is 200 bar, the heating temperature is 40°C, the heating pressure is 100 bar, the maximum temperature is 120°C, and the maximum pressure is 150 bar. The other steps are the same as those in Example 1.

[0082] The obtained laminate was tested, and the test results are shown in Table 3:

[0083] Table 3

[0084]

[0085] From the data in the table, we know that the sheet thickness of all solutions meets the requirement of 130±2mm. For Example 5, the pressure is small, and the sheet does not have a fiber extrusion slide plate. There are small pores inside the sheet and it is not dense. The bearing capacity is smaller than other solutions, and the vertical layer bearing capacity and arc resistance are the worst. For Example 6, the pressure is high. There is no high pressure maintenance when the temperature is not raised in the initial stage. After the temperature is raised, the resin paste has high fluidity, and the high pressure causes fiber extrusion. For Example 7, there is high pressure maintenance in the initial stage, and the pressure is released after the temperature is raised, and then the pressure is gradually increased. The sheet does not have fiber extrusion, but because the heating is stopped when the highest temperature of the surface is 120°C, the middle temperature does not reach the curing temperature, the sheet is not cured in the middle, and the measured performance is poor. In the initial stage of Example 1, the pressure is maintained at 200 bar. When the temperature rises to 40°C, the pressure is released and the air is exhausted. The pressure is then gradually increased to 230 bar. When the surface material temperature reaches 145°C and the middle temperature is 130°C, the heating is stopped. The composite board of 130 mm is fully cured, and the vertical layer bearing capacity and arc resistance are the best. The thickness and bearing capacity also meet the requirements.

[0086] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A composite insulating laminate with high vertical layer bearing capacity, characterized in that: It comprises an upper layer, a middle layer and a lower layer, wherein the upper layer and the lower layer are provided with 4-7 UPGM203 layers respectively, and the middle layer is formed by alternatingly stacking 1 EPGC201 layer and 1-3 UPGM203 layers, and the total thickness of the laminate is 130±2mm.

2. A composite insulating laminate with high vertical layer bearing capacity according to claim 1, characterized in that: The single piece specification of the UPGM203 layer is 2.0kg / pcs*1040*1250mm, and the single piece specification of the EPGC201 layer is 0.56kg / pcs*1050*1260mm.

3. A composite insulating laminate with high vertical layer bearing capacity according to claim 1 or 2, characterized in that: The total weight of the laminate was 348 kg.

4. A method for preparing a composite insulating laminate with high vertical layer bearing capacity, comprising the following steps: First, 95-105 parts by weight of resin, 135-145 parts by weight of aluminum hydroxide filler, 4.5-5.5 parts by weight of polyethylene powder, 1.5-2.5 parts by weight of color paste, 1.1-1.5 parts by weight of release agent, 1.1-1.5 parts by weight of curing agent, 4.5-5.5 parts by weight of styrene, and 1.3-1.7 parts by weight of slow-release thickener are stirred in a reaction kettle to obtain a resin paste; Secondly, the coiled alkali-free chopped fiber mat is impregnated with resin paste to make a prepreg, which is then cut into single prepregs of 1040*1250mm after thickening; Furthermore, the prepreg is weighed and stacked to the required thickness in the form of 4-7 UPGM203 layers on the bottom layer, 1 EPGC201 layer and 1-3 UPGM203 layers on the middle layer, and 4-7 UPGM203 layers on the bottom layer; Finally, the laminate is put through a laminator to control the temperature and pressure for hot pressing to obtain a laminate with a predetermined thickness.

5. The method for preparing a composite insulating laminate with high vertical layer bearing capacity according to claim 4, characterized in that: The impregnation content of the coil material is 650-750g / ㎡.

6. The method for preparing a composite insulating laminate with high vertical layer bearing capacity according to claim 4, characterized in that: The temperature and pressure of the laminator are controlled as follows: the initial temperature is 25-35°C and the pressure is 160-240 bar; then the temperature is increased to 35-45°C, the pressure is 80-120 bar, and the heating rate is 1-2°C / min; the temperature is further increased to 140-150°C, the pressure is 220-240 bar, and the heating rate is 1-2°C / min.

7. The method for preparing a composite insulating laminate with high vertical layer bearing capacity according to claim 4 or 6, characterized in that: The temperature and pressure control of the laminator are as follows: the starting temperature is 25-35°C, the pressure is maintained at 160-240 bar, when the temperature rises by 8-12°C, the pressure is released to 80-120 bar, and then the pressure is gradually increased to 230 bar. When the temperature of the surface material reaches 140-150°C, the intermediate temperature is 125-135°C, and the heating is stopped.

8. The method for preparing a composite insulating laminate with high vertical layer bearing capacity according to claim 4, characterized in that: The particle size of the aluminum hydroxide filler is 24-26 um.

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