WO2018072137A1 - Structural adhesive paper and preparation method therefor - Google Patents

Abstract

Provided in the present invention are a structural adhesive paper and a preparation method therefor. The structural adhesive paper comprises: a first adhesive layer, attached on a release film; a substrate, located on a side of the first adhesive layer that is far from the release film; and a second adhesive layer, which is located between the first adhesive layer and the substrate and which comprises a second adhesive. The first adhesive layer comprises: a first adhesive, as well as foaming agent particles, distributed on the first adhesive. The surface of the first adhesive layer that is far from the release film is a first surface, and a surface of the first adhesive layer that is close to the release film is a second surface. Some of the foaming agent particles are exposed from the first surface and embedded in the second adhesive layer, and the second surface of the first adhesive layer is attached to the release film. The structural adhesive paper has the advantages of a flat surface, consistent thickness and easy adhesion on objects to be adhered. The structural adhesive paper has high adhesive consistency to the objects to be adhered, and is easily mass-produced.

Description

Structural adhesive paper and preparation method thereof Technical field

The invention relates to the field of adhesive tape, in particular to a structural adhesive tape and a preparation method thereof.

Background technique

The prior art adhesive tape is generally foamed by using a PET substrate and an acrylate-based pressure-sensitive adhesive plus a foaming agent particle to cause peeling with a blank current collector (a current collector of the uncoated electrode slurry) to A tab slot is reserved on the blank current collector. Referring to FIGS. 8A and 8B, when the residual solvent amount of the adhesive layer 2' is excessively large (>10%), the blowing agent particles 21' are completely coated in the adhesive even if the blowing agent particles 21' After expansion after foaming, it is also impossible to effectively reduce the contact area between the adhesive and the blank current collector, which makes the adhesive paper difficult to peel off, and it is impossible to reserve a ferrule on the blank current collector. Referring to FIGS. 9A and 9B, when the amount of residual solvent of the adhesive layer 2' is relatively suitable (5% to 10%), part of the blowing agent particles 21' are placed at the interface between the adhesive and the blank current collector, After the foaming agent particles 21' are foamed, the contact area between the adhesive and the blank current collector can be effectively reduced, and the adhesive paper can be peeled off normally, but the process is demanding and the qualification rate is low, which cannot meet the demand for mass production. Referring to FIGS. 10A and 10B, when the residual solvent amount of the adhesive layer 2' is too low (<5%), most of the blowing agent particles 21' have been exposed outside the adhesive, and the blowing agent particles 21' After foaming, the adhesive almost lost its bond with the blank current collector, causing the adhesive paper to become tacky and contaminate the oven.

In addition, since the foaming agent particles in the adhesive layer are exposed, the bonding interface between the adhesive layer and the blank current collector is not flat, and the thickness of the adhesive layer is usually required to be small, and the precision of the coating process is conventional. Unable to meet the requirements, thickness fluctuations lead to a large number of products scrapped.

Summary of the invention

In view of the problems in the prior art, it is an object of the present invention to provide a structural adhesive tape having a smooth surface, a uniform thickness, and easy to be attached to an object to be bonded.

Another object of the present invention is to provide a structural adhesive tape and a preparation method thereof, the structural adhesive tape The viscosity consistency with the object to be bonded is extremely high, and it is easy to carry out batch production, and solves the problem that the viscosity of the foaming agent particles in the conventional adhesive tape is severe after foaming.

Another object of the present invention is to provide a structural adhesive tape and a preparation method thereof, which can improve the utilization rate of the active material of the battery, avoid waste of the active material, and improve the energy density and fast-release performance of the battery. And heat dissipation.

In order to achieve the above object, in one aspect of the invention, the present invention provides a structural adhesive tape comprising: a first adhesive layer attached to a release film; and a substrate disposed on the first adhesive layer a side away from the release film; and a second adhesive layer between the first adhesive layer and the substrate and including a second adhesive. The first adhesive layer comprises: a first adhesive; and a foaming agent particle distributed on the first adhesive, and the quality of the foaming agent particles is the sum of the masses of the first adhesive and the foaming agent particles 20% to 70%. The surface of the first adhesive layer away from the release film is a first surface, and the surface of the first adhesive layer adjacent to the release film is a second surface. Part of the blowing agent particles are exposed on the first surface and embedded in the second adhesive layer, and the second surface of the first adhesive layer is attached to the release film.

In another aspect of the invention, the invention provides a method for preparing a structural adhesive paper for preparing the structural adhesive paper according to one aspect of the invention, comprising the steps of: first adhesive, foaming agent particles And the first solvent is stirred to form a slurry of the first adhesive layer, and the slurry of the first adhesive layer is coated on the release film, wherein the surface of the first adhesive layer away from the release film a first surface, the surface of the first adhesive layer adjacent to the release film is a second surface, heated to a first temperature for drying to remove the first solvent, and a portion of the blowing agent particles are exposed to the first adhesive The first layer of the first adhesive layer is adjacent to the first surface of the release film, and the second surface of the first adhesive layer is adjacent to the release film, wherein the first temperature is lower than the release of the foaming agent particles. The bubble temperature, the mass of the foaming agent particles is 20% to 70% of the sum of the masses of the first adhesive and the foaming agent particles; and the second adhesive and the second solvent are stirred to form the second adhesive layer Slurry, coating the slurry of the second adhesive layer on the substrate, heating to a second temperature for drying to remove the first a solvent; curing the first surface of the first adhesive layer away from the release film and the surface of the second adhesive layer away from the substrate and heating to a third temperature for curing, the third temperature is low At the foaming temperature of the foaming agent particles, the preparation of the structural adhesive paper is completed.

Compared with the prior art, the beneficial effects of the present invention are:

The structural adhesive paper of the present invention has a flat surface, a good thickness consistency, and is easy to be attached to the object to be bonded.

The structural adhesive tape of the invention has extremely high viscosity consistency with the object to be bonded, and is easy to be mass-produced. The production solves the problem that the viscosity of the foaming agent particles in the conventional adhesive tape is severe after foaming.

The structural adhesive tape of the invention can improve the utilization rate of the active material of the battery, avoid the waste of the active material, and at the same time improve the energy density, fast-release performance and heat dissipation performance of the battery.

DRAWINGS

1 is a perspective view of a current collector of a bonded object applied to a structural adhesive tape of the present invention;

2 is a perspective view of the structural adhesive tape of the present invention adhered to a current collector of the object to be bonded, wherein the release film of the structural adhesive tape is peeled off;

3 is a perspective view of the structural adhesive paper-coated electrode slurry of the present invention, wherein the release film of the structural adhesive paper is peeled off;

Figure 4 is a perspective view of the structural adhesive tape of the present invention after peeling off;

Figure 5 is a perspective view of the structural adhesive tape of the present invention;

Figure 6 is a front view of Figure 5;

Figure 7 is a schematic view showing the pressure composite of the structural adhesive tape of the present invention;

8A to 8B are schematic views of an embodiment of a prior art adhesive tape, wherein FIG. 8A shows a schematic view of the foaming agent particles before foaming, and FIG. 8B shows a schematic view of the foaming agent particles after foaming;

9A to 9B are schematic views showing another embodiment of the prior art adhesive tape, wherein FIG. 9A shows a schematic view of the foaming agent particles before foaming, and FIG. 9B shows a schematic view of the foaming agent particles after foaming;

10A to 10B are schematic views showing still another embodiment of the prior art adhesive tape, wherein Fig. 10A shows a schematic view of the foaming agent particles before foaming, and Fig. 10B shows a schematic view of the foaming agent particles after foaming.

Among them, the reference numerals are as follows:

1 structural adhesive tape

11 first adhesive layer

111 blowing agent particles

11S1 first surface

11S2 second surface

12 second adhesive layer

13 substrate

M release film

2 current collector

21 reserved area

3 electrode paste

W width direction

L length direction

T thickness direction

1' substrate

2' adhesive layer

21' foaming agent granule

detailed description

The structural adhesive paper according to the present invention and a method for producing the same are explained in detail below.

First, the structural adhesive tape according to the first aspect of the invention will be explained.

Referring to FIG. 3, FIG. 5 to FIG. 6, the structural adhesive tape 1 according to the first aspect of the present invention comprises: a first adhesive layer 11 attached to the release film M; and a substrate 13 located at the first adhesive. a side of the layer 11 remote from the release film M; and a second adhesive layer 12 between the first adhesive layer 11 and the substrate 13 and including a second adhesive. The first adhesive layer 11 includes: a first adhesive; and foaming agent particles 111 distributed on the first adhesive, and the mass of the blowing agent particles 111 is the first adhesive and the blowing agent particles 111 20% to 70% of the sum of the quality. The surface of the first adhesive layer 11 remote from the release film is the first surface 11S1, and the surface of the first adhesive layer 11 near the release film is the second surface 11S2. Part of the blowing agent particles 111 are exposed on the first surface 11S1 and embedded in the second adhesive layer 12, and the second surface 11S2 of the first adhesive layer 11 is attached to the release film M.

In the structural adhesive sheet 1 according to the first aspect of the invention, the mass of the blowing agent particles 111 is 20% to 70% of the sum of the masses of the first adhesive agent and the blowing agent particles 111, and the blowing agent particles The mass percentage of 111 is too high, which tends to cause early loss of adhesion of the structural adhesive tape, and the mass percentage of the foaming agent particles 111 is too low, which is likely to cause poor foaming. Wherein, the lower limit value of the mass percentage of the blowing agent particles 111 may be 20%, 25%, 30%, and the lower limit value of the mass percentage of the blowing agent particles 111 may be 30%, 35%, 40 %, 45%, 50%, 55%, 60%, 65%, 70%. Preferably, the mass of the blowing agent particles 111 is the sum of the masses of the first adhesive and the blowing agent particles 111. 25% to 35%.

In the structural adhesive sheet 1 according to the first aspect of the invention, the second adhesive layer 12 contains no blowing agent particles.

In the structural adhesive sheet 1 according to the first aspect of the invention, the first adhesive layer 11 has a thickness of 40 μm to 50 μm.

In the structural adhesive sheet 1 according to the first aspect of the invention, the second adhesive layer 12 has a thickness of 4 μm to 10 μm.

In the structural adhesive sheet 1 according to the first aspect of the invention, the first adhesive is one or more selected from the group consisting of an acrylate type adhesive and a urethane adhesive.

In the structural adhesive sheet 1 according to the first aspect of the invention, the second adhesive is one or more selected from the group consisting of an acrylate type adhesive and a urethane adhesive.

In the structural adhesive sheet 1 according to the first aspect of the invention, the material of the first adhesive and the second adhesive may be different.

In the structural adhesive sheet 1 according to the first aspect of the invention, the substrate 13 has a thickness of 15 μm to 36 μm.

In the structural adhesive sheet 1 according to the first aspect of the invention, the substrate 13 is selected from the group consisting of polyethylene terephthalate (PET).

In the structural adhesive sheet 1 according to the first aspect of the invention, the particle size of the blowing agent particles 111 is from 5 μm to 30 μm.

In the structural adhesive sheet 1 according to the first aspect of the invention, the blowing agent particles 111 are physical blowing agents and/or chemical blowing agents. The physical foaming agent is an alkane long chain series foaming agent. Preferably, the physical blowing agent is selected from one or more of an isopentane blowing agent, an isobutane blowing agent, and a cyclopentane blowing agent. The chemical blowing agent is selected from the group consisting of azodicarbonamide, azobisisobutyronitrile, N,N-dinitrosopentamethylenetetramine, 4,4'-oxobisbenzenesulfonyl hydrazide, One or more of tosylhydrazide.

In the structural adhesive sheet 1 according to the first aspect of the invention, the first adhesive layer 11 and/or the second adhesive layer 12 further includes a curing agent. The curing agent in the first adhesive layer 11 may be the same as or different from the curing agent in the second adhesive layer 12.

In the structural adhesive sheet 1 according to the first aspect of the invention, the curing agent may be a room temperature curing agent. Preferably, the curing agent is selected from one or more of an aliphatic polyamine, an alicyclic polyamine, a polyamide (preferably a low molecular weight polyamide), a modified aromatic amine, and an isocyanate.

In the structural adhesive sheet 1 according to the first aspect of the invention, preferably, the release film M may be a silicone oil-coated PET film.

In the structural adhesive sheet 1 according to the first aspect of the present invention, when the structural adhesive sheet 1 is used, the release film M in the structural adhesive sheet 1 is peeled off, and the exposed first adhesive layer 11 is used for being pasted. Bonded to the object.

Referring to FIGS. 1 to 4, in the structural adhesive sheet 1 according to the first aspect of the present invention, the object to be bonded may be a blank current collector 2, and the structure is applied before the electrode paste 3 is applied on the blank current collector 2. The release film M in the adhesive tape 1 is peeled off, and the first adhesive layer 11 of the structural adhesive tape 1 is pasted on the reserved region 21 of the blank current collector 2 forming the tabs, when coated on the blank current collector 2 After the electrode paste 3 is discharged, the electrode paste 3 is dried. After the drying is completed, the structural adhesive tape 1 is peeled off to form a reserved area 21 of the tab.

Next, a method of preparing a structural adhesive tape according to the second aspect of the present invention will be described.

Referring to Figure 7, a method for preparing a structural adhesive paper according to a second aspect of the present invention is for use in the preparation of the structural adhesive paper 1 of the first aspect of the present invention, comprising the steps of: first adhesive, foaming agent particles 111, and The slurry of the first adhesive layer 11 is stirred by a solvent, and the slurry of the first adhesive layer 11 is coated on the release film M, wherein the first adhesive layer 11 is away from the release film. The surface of M is the first surface 11S1, and the surface of the first adhesive layer 11 close to the release film M is the second surface 11S2, heated to a first temperature for drying to remove the first solvent, and a partial foaming agent The particle 111 is exposed on the first surface 11S1 of the first adhesive layer 11 away from the release film M, and the second surface 11S2 of the first adhesive layer 11 near the release film M remains adhered to the release film M. Wherein the first temperature is lower than the foaming temperature of the blowing agent particles 111, and the mass of the blowing agent particles 111 is 20% to 70% of the sum of the masses of the first adhesive agent and the blowing agent particles 111; The second adhesive and the second solvent are stirred to form a slurry of the second adhesive layer 12, and the slurry of the second adhesive layer 12 is coated on the substrate 13. Heating to a second temperature for drying to remove the second solvent; pressing the first surface 11S1 of the first adhesive layer 11 away from the release film M and the surface of the second adhesive layer 12 away from the substrate 13 The composite is heated and heated to a third temperature for curing, which is lower than the foaming temperature of the blowing agent particles 111, that is, the preparation of the structural adhesive paper 1 is completed.

In the method of producing the structural adhesive sheet 1 according to the second aspect of the present invention, the partial blowing agent particles 111 are exposed to the first adhesive layer 11 when heated to a first temperature for drying to remove the first solvent. Along from the first surface 11S1 of the release film M, the second surface 11S2 of the first adhesive layer 11 close to the release film M is adhered to the release film M, so when the release film M is peeled off, The second surface 11S2 of the adhesive layer 11 is kept flat, so that the structural adhesive paper 1 has a uniform thickness and is easily attached to the object to be bonded. At the same time, since the partial foaming agent particles 111 in the vicinity of the first surface 11S1 are exposed due to the drying, although the blowing agent particles 111 in the vicinity of the second surface 11S2 are not exposed due to the presence of the release film M, the structural adhesive paper 1 is During use (release film M is peeled off, exposed first adhesive layer 11 is applied to the object to be bonded, such as stuck on the current collector 2 of FIG. 1), and the foaming agent particles 111 are foamed. It is easy to break through the second surface 11S2 of the first adhesive layer 11, and the structural adhesive paper 1 is neither completely detached from the object to be bonded nor completely attached, so that the structural adhesive tape 1 is easily peeled off from the bonded object. The post-foam structure adhesive paper 1 has good consistency of adhesion, and does not cause poor foaming and residual glue.

In the method for producing the structural adhesive sheet 1 according to the second aspect of the present invention, after the first temperature is removed by heating to the first temperature, the residual amount of the first solvent accounts for the slurry of the first adhesive layer 11. The ratio of the total weight is not more than 1%.

In the method for producing the structural adhesive sheet 1 according to the second aspect of the present invention, after the second temperature is removed by heating to the second temperature, the residual amount of the second solvent accounts for the slurry of the second adhesive layer 12. The ratio of the total weight is not more than 1%.

In the method of producing the structural adhesive sheet 1 according to the second aspect of the present invention, the first temperature is from 75 ° C to 85 ° C, and the baking time is not less than 2 min.

In the method of producing the structural adhesive sheet 1 according to the second aspect of the present invention, the second temperature is from 75 ° C to 85 ° C, and the baking time is not less than 1 min.

In the method for producing the structural adhesive sheet 1 according to the second aspect of the present invention, the third temperature is 40 ° C to 45 ° C, and the curing time is 48 h to 72 h.

In the method of producing the structural adhesive sheet 1 according to the second aspect of the present invention, the coating of the slurry of the first adhesive layer 11 is selected from extrusion coating, blade coating, spray coating or transfer coating.

In the method of producing the structural adhesive sheet 1 according to the second aspect of the present invention, the coating of the slurry of the second adhesive layer 12 is selected from extrusion coating, blade coating, spray coating or transfer coating.

In the method for preparing the structural adhesive tape 1 according to the second aspect of the present invention, the first adhesive layer 11 of the first adhesive layer 11 away from the release film M and the second adhesive layer 12 are away from the substrate. The surface of 13 is compounded under a pressure of 5 kg to 12 kg.

In the method of manufacturing the structural adhesive sheet 1 according to the second aspect of the present invention, the first surface 11S1 of the first adhesive layer 11 away from the release film M and the second adhesive layer 12 may be away from the base. The surface of the material 13 is first pressure-composited, and then heated to a third temperature for curing; or the first surface 11S1 of the first adhesive layer 11 away from the release film M and the second adhesive layer 12 may be away from the base. The surface of the material 13 is heated to a third temperature while being pressed and composited to be aged.

The present application is further illustrated below in conjunction with the embodiments. It is to be understood that the examples are not intended to limit the scope of the application.

Example 1

At room temperature, the first adhesive acrylate adhesive, foaming agent particles cyclopentane (filtered through a 150 mesh sieve, foaming temperature of 120 ° C ~ 130 ° C) and ethyl acetate at 40 rpm ~ 60 rpm The slurry of the first adhesive layer was prepared by stirring for 30 minutes, wherein the mass of the blowing agent particles was 25% of the sum of the masses of the first adhesive and the blowing agent particles. The slurry of the first adhesive layer is coated on the release film by a doctor blade to form a roll I, and the roll I is heated to an oven temperature of 75 ° C for 2 min to remove ethyl acetate (the residual amount is not more than 1%) The speed of the coil I is 10m/min~12m/min, the thickness of the slurry coating is 40μm, and the part of the blowing agent particle cyclopentane is exposed to the first layer of the first adhesive layer away from the release film. The surface, the second surface of the first adhesive layer adjacent to the release film remains attached to the release film.

A slurry of the second adhesive layer was prepared by stirring the second adhesive acrylate type adhesive and toluene at a rotation speed of 40 rpm to 60 rpm for 30 minutes. The slurry of the second adhesive layer is coated on the substrate PET (thickness 15 μm) by a doctor blade to form a roll II, and the roll II is heated to an oven temperature of 75 ° C for 2 min to remove toluene (the residual amount is not More than 1%), the winding speed of the coil II is 10 m/min to 12 m/min, and the thickness of the slurry coating is 5 μm.

The first surface of the first adhesive layer in the roll I away from the release film and the surface of the second adhesive layer in the roll II away from the substrate are combined under a pressure of 6 kg, and the recombination speed is 5 m/min~ 45 m / min, after heating to 45 ° C for 60 h, the completion of the preparation of structural adhesive tape.

The release film is peeled off, the first adhesive layer of the structural adhesive tape is pasted on the blank current collector aluminum foil, the positive electrode slurry is coated on the current collector, and then placed in an oven to heat the foaming agent particles cyclopentane. The structural adhesive tape is curled. After the positive electrode slurry layer is completely dried, the current collector is removed from the oven and passed through the mechanical hair. The brush peels off the structural adhesive tape, which forms a reserved area for the tabs.

Table 1 gives the test results of the parallel test, and the structural adhesive tape is pasted on the current collector to make the patch flat, without the appearance of oblique rubber or wrinkles.

Table 1 Thickness of the structural adhesive tape of Example 1 and viscosity results after foaming

Example 2

At room temperature, the first adhesive acrylate adhesive, foaming agent particles cyclopentane (filtered through a 150 mesh sieve, foaming temperature of 120 ° C ~ 130 ° C) and ethyl acetate at 40 rpm ~ 60 rpm The slurry of the first adhesive layer was prepared by stirring for 30 minutes, wherein the mass of the blowing agent particles was 60% of the sum of the masses of the first adhesive and the blowing agent particles. The slurry of the first adhesive layer is coated on the release film by a doctor blade to form a roll I, and the roll I is heated to an oven temperature of 75 ° C for 2 min to remove ethyl acetate (the residual amount is not more than 1%) The speed of the coil I is 10m/min~12m/min, the thickness of the slurry coating is 50μm, and the part of the blowing agent particle cyclopentane is exposed to the first layer of the first adhesive layer away from the release film. The surface, the second surface of the first adhesive layer adjacent to the release film remains attached to the release film.

A slurry of the second adhesive layer was prepared by stirring the second adhesive acrylate type adhesive and toluene at a rotation speed of 40 rpm to 60 rpm for 30 minutes. The slurry of the second adhesive layer is coated on the substrate PET (thickness 15 μm) by a doctor blade to form a roll II, and the roll II is heated to an oven temperature of 75 ° C for 2 min to remove toluene (the residual amount is not More than 1%), the winding speed of the coil II is 10 m/min to 12 m/min, and the thickness of the slurry coating is 5 μm.

The first surface of the first adhesive layer in the roll I away from the release film and the surface of the second adhesive layer in the roll II away from the substrate are combined under a pressure of 6 kg, and the recombination speed is 5 m/min~ 45 m / min, after heating to 45 ° C for 60 h, the completion of the preparation of structural adhesive tape.

The release film is peeled off, the first adhesive layer of the structural adhesive tape is pasted on the blank current collector aluminum foil, the positive electrode slurry is coated on the current collector, and then placed in an oven to heat the foaming agent particles cyclopentane. Knot The adhesive paper is curled. After the positive slurry layer is completely dried, the current collector is removed from the oven, and the structural adhesive paper is peeled off by a mechanical brush to form a reserved area of the tab.

Table 2 gives the test results of the parallel test, and the structural adhesive tape is pasted on the current collector to make the patch flat, without the appearance of oblique rubber or wrinkle.

Table 2 Thickness of the structural adhesive tape of Example 2 and viscosity results after foaming

Comparative example 1

At room temperature, the adhesive acrylate adhesive, foaming agent particles cyclopentane (filtered through a 150 mesh sieve, foaming temperature of 120 ° C ~ 130 ° C) and ethyl acetate stirred at 40 rpm ~ 60 rpm for 30 min A slurry is prepared in which the mass of the blowing agent particles is 25% of the sum of the masses of the binder and the blowing agent particles. The slurry was coated on a substrate PET (thickness 15 μm) by a doctor blade to form a roll, and the roll was heated to an oven temperature of 75 ° C for 2 min to remove ethyl acetate, and the roll speed was 10 m/min to 12 m. /min, the slurry coating thickness was 50 μm. After heating to 45 ° C for 60 h, the preparation of the structural adhesive tape is completed.

The adhesive layer of the structural adhesive tape is pasted on the blank current collector aluminum foil, the positive electrode slurry is coated on the current collector, and then placed in an oven to heat the foaming agent particles cyclopentane, and the structural adhesive paper is curled. After the positive slurry layer is completely dried, the current collector is removed from the oven, and the structural adhesive tape is peeled off by a mechanical brush to form a reserved area of the tab.

Table 3 gives the test results of the parallel test, and the result of the structural adhesive tape sticking to the current collector is as follows: 10% of the structural adhesive paper is unevenly attached, wherein the ratio of the oblique rubber is 3%, and the ratio of the wrinkles is 7%.

Table 3 Thickness of structural adhesive paper of Comparative Example 1 and viscosity results after foaming

Comparative example 2

The slurry of the first adhesive layer was prepared by stirring the first adhesive acrylate type adhesive and toluene at a rotation speed of 40 rpm to 60 rpm for 30 minutes at room temperature. The blowing agent particles cyclopentane (foaming temperature is 120 ° C ~ 130 ° C) are filtered through a 150 mesh sieve, and then stirred with a second adhesive acrylate adhesive, ethyl acetate at a speed of 40 rpm to 60 rpm. A slurry of the second adhesive layer was prepared for 30 minutes, wherein the mass of the blowing agent particles was 25% of the sum of the masses of the second adhesive and the blowing agent particles.

The slurry of the second adhesive layer was coated on a substrate PET (thickness: 15 μm) by a doctor blade to form a roll I, and the roll I was heated to an oven temperature of 75 ° C for 2 min to remove ethyl acetate. The roll I has a running speed of 10 m/min to 12 m/min, the slurry coating thickness is 40 μm, and a part of the blowing agent particles cyclopentane is exposed on the surface of the second adhesive layer away from the substrate PET.

Then, the slurry forming material roll II of the first adhesive layer is disposed on the second adhesive layer of the roll I by gravure coating, and the roll II is heated to an oven temperature of 75 ° C for 2 min to remove Toluene, the roll speed of the roll II is from 10 m/min to 12 m/min, and the thickness of the slurry coating is 5 μm, so that the above-mentioned foaming agent particles cyclopentane exposed on the surface of the second adhesive layer are embedded in the first adhesive. The layer remains unexposed to the surface of the first adhesive layer away from the substrate PET.

The mixture was aged to 45 ° C for 60 h to complete the preparation of structural adhesive tape.

The first adhesive layer of the structural adhesive tape is pasted on the blank current collector aluminum foil, the positive electrode slurry is coated on the current collector, and then heated in an oven to foam the foaming agent particles cyclopentane, and the structural adhesive paper is curled. After the positive electrode slurry layer is completely dried, the current collector is removed from the oven, and the structural adhesive tape is peeled off by a mechanical brush to form a reserved area of the tab.

Table 4 gives the test results of the parallel test, and the result of the structural adhesive tape sticking on the current collector is that the 5% structural adhesive paper is unevenly attached, wherein the ratio of the oblique rubber is 1%, and the ratio of the wrinkles is 4%.

Table 4 Thickness of structural adhesive paper of Comparative Example 2 and viscosity results after foaming

Compared with Example 1-2, the structural adhesive paper of Comparative Example 1 was inferior in thickness consistency, and the adhesive consistency of the structural adhesive paper after foaming was also poor. The thickness consistency of the structural adhesive paper in Comparative Example 2 was also poor, because in Comparative Example 2, the first adhesive layer bonded to the blank current collector was relatively thin, only 5 μm, and usually the blowing agent particles. The particle size distribution itself is 5 μm to 30 μm, and since part of the foaming agent particles exposes the surface of the second adhesive layer away from the surface of the substrate PET, it is impossible to continue coating the slurry of the first adhesive layer thereon. The flatness of the first adhesive layer is ensured, and thus the bonding surface of the structural adhesive tape cannot be ensured, and the consistency of the thickness of the structural adhesive tape is not guaranteed. If the thickness of the first adhesive layer is increased, the foaming agent particles are not exposed after being foamed, which tends to cause the structural adhesive tape to be easily peeled off, and a residual glue is formed on the current collector.

Claims (22)

A structural adhesive tape (1), characterized in that it comprises: The first adhesive layer (11) is attached to the release film (M) and includes: First adhesive; The blowing agent particles (111) are distributed on the first adhesive, and the mass of the blowing agent particles (111) is 20% to 70% of the sum of the masses of the first adhesive and the blowing agent particles (111). ; a substrate (13) on a side of the first adhesive layer (11) remote from the release film (M); a second adhesive layer (12) between the first adhesive layer (11) and the substrate (13) and comprising a second adhesive; The surface of the first adhesive layer (11) away from the release film (M) is the first surface (11S1), and the surface of the first adhesive layer (11) near the release film (M) is the second surface. (11S2), a portion of the blowing agent particles (111) are exposed on the first surface (11S1) and embedded in the second adhesive layer (12), and the second surface (11S2) of the first adhesive layer (11) Attached to the release film (M). The structural adhesive paper (1) according to claim 1, wherein the mass of the blowing agent particles (111) is 25% to 35 of the sum of the masses of the first adhesive and the blowing agent particles (111). %. The structural adhesive tape (1) according to claim 1, wherein the first adhesive layer (11) has a thickness of from 40 μm to 50 μm. The structural adhesive tape (1) according to claim 1, wherein the second adhesive layer (12) has a thickness of from 4 μm to 10 μm. The structural adhesive tape (1) according to claim 1, wherein the first adhesive is one or more selected from the group consisting of an acrylate type adhesive and a urethane adhesive; The adhesive is selected from one or more of an acrylate type adhesive and a urethane adhesive. The structural adhesive tape (1) according to claim 1, wherein the first adhesive and the first adhesive The material of the second adhesive is different. The structural adhesive tape (1) according to claim 1, wherein the substrate (13) has a thickness of from 15 μm to 36 μm. A structural adhesive paper (1) according to claim 1, characterized in that the substrate (13) is selected from the group consisting of polyethylene terephthalate. The structural adhesive paper (1) according to claim 1, wherein the foaming agent particles (111) have a particle diameter of from 5 μm to 30 μm. A structural adhesive paper (1) according to claim 9, characterized in that the blowing agent particles (111) are physical blowing agents and/or chemical blowing agents. The structural adhesive tape (1) according to claim 10, characterized in that The physical blowing agent is selected from one or more of an isopentane blowing agent, an isobutane blowing agent, and a cyclopentane blowing agent; The chemical blowing agent is selected from the group consisting of azodicarbonamide, azobisisobutyronitrile, N,N-dinitrosopentamethylenetetramine, 4,4'-oxobisbenzenesulfonyl hydrazide, One or more of tosylhydrazide. The structural adhesive tape (1) according to claim 1, characterized in that the first adhesive layer (11) and/or the second adhesive layer (12) further comprise a curing agent. The structural adhesive paper (1) according to claim 12, wherein the curing agent is one or more selected from the group consisting of an aliphatic polyamine, an alicyclic polyamine, a polyamide, a modified aromatic amine, and an isocyanate. Kind. A method for preparing a structural adhesive paper (1) for preparing the structural adhesive paper (1) according to any one of claims 1 to 13, comprising the steps of: The first adhesive, the blowing agent particles (111) and the first solvent are stirred to form a slurry of the first adhesive layer (11), and the slurry of the first adhesive layer (11) is coated on the slurry. Release film (M), which The surface of the first adhesive layer (11) away from the release film (M) is a first surface (11S1), and the surface of the first adhesive layer (11) close to the release film (M) is Two surfaces (11S2), heated to a first temperature for drying to remove the first solvent, and exposing part of the blowing agent particles (111) to the first adhesive layer (11) away from the release film (M) a first surface (11S1), a second surface (11S2) of the first adhesive layer (11) adjacent to the release film (M) remains attached to the release film (M), wherein the first temperature is low The foaming agent particles (111) have a foaming temperature of 20% to 70% of the sum of the masses of the first binder and the foaming agent particles (111); The second adhesive and the second solvent are stirred to form a slurry of the second adhesive layer (12), and the slurry of the second adhesive layer (12) is coated on the substrate (13), and heated. Drying to a second temperature to remove the second solvent; Pressing the first surface (11S1) of the first adhesive layer (11) away from the release film (M) and the surface of the second adhesive layer (12) away from the substrate (13) by pressure and heating to The third temperature is aged, and the third temperature is lower than the foaming temperature of the blowing agent particles (111), that is, the preparation of the structural adhesive paper (1) is completed. The method for preparing a structural adhesive tape (1) according to claim 14, wherein after the first temperature is removed by heating to the first temperature, the residual amount of the first solvent occupies the first adhesive layer (11). The ratio of the total weight of the slurry is not more than 1%. The method for preparing a structural adhesive tape (1) according to claim 14, wherein after the second temperature is removed by heating to a second temperature, the residual amount of the second solvent occupies the second adhesive layer (12). The ratio of the total weight of the slurry is not more than 1%. The method of producing a structural adhesive sheet (1) according to claim 14, wherein the first temperature is from 75 ° C to 85 ° C. The method of producing a structural adhesive sheet (1) according to claim 14, wherein the second temperature is from 75 ° C to 85 ° C. The method for preparing a structural adhesive sheet (1) according to claim 14, wherein The three temperatures are from 40 ° C to 45 ° C. The method for preparing a structural adhesive tape (1) according to claim 14, wherein the slurry of the first adhesive layer (11) is applied by extrusion coating, blade coating, spraying or Transfer coating. The method for preparing a structural adhesive tape (1) according to claim 14, wherein the slurry of the second adhesive layer (12) is applied by extrusion coating, blade coating, spraying or Transfer coating. The method for preparing a structural adhesive tape (1) according to claim 14, characterized in that the first surface (11S1) of the first adhesive layer (11) away from the release film (M) and the second adhesive The surface of the adhesive layer (12) remote from the substrate (13) is compounded under a pressure of 5 kg to 12 kg.

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