WO2018072161A1

WO2018072161A1 - Heat-expandable removable pressure-sensitive adhesive tape and manufacturing method thereof

Info

Publication number: WO2018072161A1
Application number: PCT/CN2016/102663
Authority: WO
Inventors: 姚海瑞; 覃国飞; 陆金亮; 王宜金; 尹嘉菲
Original assignee: 东莞市澳中电子材料有限公司
Priority date: 2016-10-20
Filing date: 2016-10-20
Publication date: 2018-04-26

Abstract

A heat-expandable removable pressure-sensitive adhesive tape and a manufacturing method thereof. The adhesive tape is made of the following components in the following percentages by mass: 1) 40.4%-66% of a pressure-sensitive adhesive, 2) 15.5%-33.5% of a heat-sensitive expandable macromolecular material; 3) 0.8%-1.6% of a cross-linking agent; 4) 2.7%-4.5% of an inorganic filler; and 5) 15%-20% of an organic solvent. The heat-expandable removable pressure-sensitive adhesive tape as described in the application has a stable adhesiveness at room temperature and shows a reduced adhesiveness after heated under high temperatures, leaving no residual adhesive and causing no contamination while easily removed from an adherend. The adhesive tape is made by a die cutting process and achieves a consistent and regular curling direction after heat expansion of the tape, and is used for continuous coating of lithium battery positive and negative electrode slurries so as to significantly improve production efficiency, increase lithium battery capacity, and reduce battery size.

Description

Heat expansion and expansion loss-sensitive pressure-sensitive adhesive tape and preparation method thereof

Technical field

The application of the invention relates to an adhesive tape, in particular to a heat-expanding, loss-adhesive pressure-sensitive adhesive tape and a preparation method thereof.

Background technique

With the development of science and technology, the degree of automation is getting higher and higher, and the continuous and simple production process is the main means to improve the competitiveness of enterprises. At present, high-end electronic products need to carry out electronic products to ensure the continuity and simplicity of the production process. Certain protective measures.

At present, the main protective measures are as follows: one is to apply a low-adhesive protective film pressure-sensitive adhesive tape, and the other is to use a UV-type pressure-sensitive adhesive tape. These two protective measures have certain drawbacks. The low-adhesive protective film pressure-sensitive adhesive tape has low adhesion and is difficult to bond rough surface objects. If it is used in high-end electronic products, the protective film After bonding, the adhesive force will increase with time, temperature and pressure, which will cause the appearance of electronic products to be destroyed when the final removal, and even the electronic products will be completely damaged. UV pressure-sensitive adhesive tape is currently the most popular adhesive tape for wafer, glass and other products. However, because UV pressure-sensitive adhesive contains low molecular weight photoinitiator, it will be low after passing harsh conditions such as temperature. Molecular weight chemical substances remain in the electronic device, which poses a certain safety hazard to the stability of the product. At the same time, the above two kinds of adhesive tapes have disadvantages for some special purposes. For example, in the coating industry, the coating shape cannot be arbitrarily changed due to coating, for example, the coating of the pole piece of the lithium battery industry needs to be coated with the slurry. There is a small blank area where the slurry cannot be applied. This blank area is mainly used to weld the tabs. If a protective film or UV tape is used, this problem cannot be solved.

In the prior art, a heat-peelable acrylate pressure-sensitive adhesive tape for coating, printing and spraying is mentioned; 100 parts of acrylate polymer and 15-40 parts of expandable microspheres are selected, and evenly mixed. Adding 0.01-2 parts of isocyanate cross-linking agent, coating on the substrate, coating dry glue thickness of 30-60um, Then, the heat-peelable pressure-sensitive adhesive tape is dried at 60-90 ° C, and the prepared heat-peelable pressure-sensitive adhesive tape is attached to a release film of 25-75 um to prepare a heat-peelable acrylate pressure-sensitive adhesive. Adhesive tape. The coated substrate has a single-sided surface energy of not less than 36 dynes. Another prior art mentions a thermally expandable, releasable acrylic pressure sensitive adhesive tape and adhesive sheet which is a highly exfoliated thermally expandable adhesive tape suitable for temporary protection of electronic product manufacturing processes.

From the current technology of expanding the adhesive tape, the expansion temperature requirement is higher, higher than 100 ° C, which is not suitable for some products produced at a lower temperature, and the use range of the expansion adhesive tape is narrow.

Summary of the invention

In view of the deficiencies in the use of the above various adhesive tapes, the present invention provides a thermal expansion loss-sensitive pressure-sensitive adhesive tape for use in die-cutting, product processing, and can be applied in the coating industry. The coating shape and the die-cut design of a certain specification form a special-purpose adhesive sheet.

The main problems to be solved by the application of the present invention are:

(1) Providing an adhesive tape which is capable of expanding and losing viscosity or having a small amount of tackiness above 50 ° C, so that the expanded adhesive tape is suitable for a wider field;

(2) Providing an adhesive sheet suitable for coating with a lithium battery, the adhesive sheet is required to expand only at a specific temperature, and the film can be more regularly curled after being expanded, and the degree of curl and expansion can completely push up the lithium. The battery pole piece coated slurry, and the slurry can not be destroyed around; while the expanded adhesive sheet needs to be slightly sticky and cannot be blown away by the wind of the oven air duct, resulting in contamination of the pole piece slurry.

In particular, the present application provides a heat-expandable, debonded pressure-sensitive adhesive tape made of the following mass percent components:

1) Pressure sensitive adhesive 40.4% ~ 66%;

2) Thermosensitive expansion type polymer material 15.5% to 33.5%;

3) Crosslinking agent 0.8% to 1.6%;

4) inorganic filler 2.7% to 4.5%;

5) Organic solvent 15% to 20%.

Further, the heat expansion and debonding pressure-sensitive adhesive tape has a solid percentage of 25% to 45%, wherein the heat-sensitive expansion polymer material and the inorganic filler are solid; the pressure-sensitive adhesive and the crosslinking agent are contained. A liquid substance having a solvent solid content of less than 100%. The percentage of solids in the range of 25-45% refers to the content of all the solids except the final removal of the organic solvent, and the pressure sensitive adhesive and the cross-linking agent themselves also have a solid substance after removing the solvent, together with the heat-sensitive swelling material and the inorganic filler. Solid ingredients.

Further, the base film for heating and expanding the loss-sensitive pressure-sensitive adhesive tape has a thickness of 6 to 36 um, and the base film is a polyester, polyimide or polyolefin film, and the expansion temperature is low (temperature range) In the adhesive tape at 70-95 ° C), the base film is a uniaxially stretched film including PET or PP. All of the above are commercially available.

Further, the pressure sensitive adhesive has a thickness of 15 to 70 um.

Further, the pressure sensitive adhesive is an acrylic pressure sensitive adhesive or a rubber type pressure sensitive adhesive, and includes a polyurethane pressure sensitive adhesive, an epoxy pressure sensitive adhesive or a saturated polyester pressure sensitive adhesive. All of the above are commercially available.

Further, the inorganic filler is a mixture of one or two of titanium dioxide, fumed silica, titanium cyan, carbon black, cobalt blue, cobalt green or graphite, and the ratio of any two mixing ranges is 0.5 to 1:1. All of the above are commercially available.

Further, the heat-sensitive expansion type polymer material is a mixture of one or both of a physical expansion microsphere, an azo compound, a nitroso compound, a sulfonyl hydrazide compound or a carbonate compound, The ratio of any two blends ranges from 1 to 0.2:1. The physical swelling microspheres are core-nuclear structures, the azo compound is azodicarbonamide, and the nitroso compound is N,N-dinitropentaethylenetetramine. (DPT), benzenesulfonyl hydrazide, sodium hydrogencarbonate, and the like. All of the above are commercially available.

Further, the organic solvent is a mixture of one or both of ethyl acetate, butyl acetate and toluene, and the ratio of mixing the two is in the range of 0.5 to 2:1. All of the above are commercially available.

Further, the crosslinking agent is a mixture of one or both of an isocyanate curing agent, an amine curing agent, an amino resin curing agent, and an aziridine curing agent, and the ratio of any two mixing ranges is 0.5. ~1:1. All of the above are commercially available.

Another object of the present invention is to provide a method for fabricating the above-described heat-expanding and loss-sensitive pressure-sensitive adhesive tape, comprising the following steps:

A. The pressure sensitive adhesive, the heat-sensitive expansion polymer material, the crosslinking agent, the inorganic filler, and the organic solvent are mixed according to the above ratio, and stirred at a speed of 600 to 1500 r/min under a high speed mixer for 15 to 40 minutes to obtain an adhesive. Agent

B, the oven or knife coater oven temperature is set between 60 ~ 120 ° C;

C. The evenly mixed adhesive is coated on the base film corona surface by a coating machine at a coating speed of 5 to 30 m/min, a coating thickness of 15 to 70 um, and dried by an oven, and the baking time is 1 to 3 minutes. , the temperature is 60-120 ° C;

D. The dried adhesive is applied to the release surface of the 16-50 um PET release film at the bonding device of the coater, and other release films such as OPP and PP;

E. Winding the bonded adhesive tape;

F. The film is placed at a temperature of 30 to 70 ° C for 24-48 hours to obtain a heat-expandable and loss-sensitive pressure-sensitive adhesive tape.

Further, in the manufacturing method, the tape is heated and expanded by a die-cutting heat, and the die-cut pattern is one of a rectangle, a square, an (elliptical) circle, a triangle, or a diamond. Die cutting is in After the tape coating is matured, it is taken as required by the specifications of the material to be protected. Die-cutting into different shapes is beneficial to improve the accuracy of the material to be protected, improve the subsequent production process and efficiency; and at the same time, according to different shapes of the tape, it is more convenient to clean and release after heating and expansion.

Further, in the manufacturing method, the die-cut pattern of the tape is rectangular (including chamfering), and the inner die of the film is creased; the crease is parallel to the short side or the long side, and the crease size is the same specification. Or different specifications parallel to each other, and the crease size is smaller than the side parallel to it. The advantages of the shape are as follows: firstly, the shape of the pole piece of the lithium battery is similar, and the shape is rectangular, so that the position of the welded pole piece is reserved; secondly, the length and width of the rectangle are inferior, and the long side deformation of the tape during the baking expansion is large, and the deformation is large. The curl is made larger; again, the tape will release a large stress during the heating and expansion process, and the die-cut crease is favorable for decomposing part of the stress, so that the curling rule is better.

The heat-expanding and loss-insensitive pressure-sensitive adhesive tape has a room temperature peeling force of 20 to 800 gf/inch for a steel plate, an aluminum foil, a copper foil and other metal sheets, and a low peeling force after baking at 90 to 130 ° C for 3 to 120 seconds. At 10gf/inch. The expanded and loss-sensitive pressure-sensitive adhesive tape is used for continuous coating of positive and negative electrodes of a lithium battery, and the materials are respectively aluminum foil and copper foil; if other protective materials are attached, there may be metal sheets such as steel plates, nickel sheets and zinc sheets; It must be sticky and retain the force with the object before it is foamed.

In the manufacturing method, the adhesive tape is attached with a release film or a release paper, and the die release film or the release paper is intact after die cutting, and the width is not less than the width of the film. The expanded adhesive sheet is formed by die-cutting of the produced expanded adhesive tape. The specific specifications are uncertain, and can be die-cut according to customer requirements. The dimensions of the underlying film of the expanded adhesive sheet for coating the lithium battery pole piece slurry are: long (100-500 m), wide (20-100 mm); the size of the adhesive sheet is: long (10-50 mm), Width (10 ~ 50mm), the size of the die cutter in the adhesive sheet is: long (2 ~ 45mm), the distance between the knife mark and the knife mark (1 ~ 20mm); the chamfer radius of the adhesive sheet R = 0 ~ 5mm .

The heat expansion and loss-loss type pressure-sensitive adhesive tape provided by the invention has the following advantages:

(1) It has stable viscosity at normal temperature, and the viscosity is reduced after baking at high temperature, and there is no pollution to the adherend without residue, which is easy to remove;

(2) Solving the consistency and regularity of the curling direction after heating and expansion of the tape, for the position protection of the positive and negative pole pieces of the lithium battery to achieve continuous coating of the slurry, greatly improving the production efficiency and increasing the capacitance of the lithium battery, reducing Battery space.

DRAWINGS

1 is a flow chart showing a manufacturing process of the heat-expanding and loss-sensitive pressure-sensitive adhesive tape according to the application of the present invention;

2 is a schematic view showing a roll shape of a heat-expanding and loss-sensitive pressure-sensitive adhesive tape film base film according to the application of the present invention;

Wherein, 1 is a rubber compounding area, 2 is a transfer type knife coating machine, 3 is a film unwinding area to be coated, 4 is a baking oven area, 5 is a bonding bottom film unwinding area, and 6 is a base film and The tape bonding roller area, 7 is a semi-finished winding area after the base film is attached, 8 is a film curing area, 9 is a base film, and 10 is a film.

detailed description

The technical solutions described in the present application are described below in conjunction with the specific embodiments, and the purpose is to better understand the technical solutions in the public, and not to limit them.

Embodiment 1

The application of the invention provides a heat-expanding, loss-adhesive pressure-sensitive adhesive tape which is made of the following mass percentage components:

1) polyurethane pressure sensitive adhesive 40.4%;

2) azo compounds 33.5%;

3) isocyanate curing agent 1.6%;

4) Titanium blue 4.5%;

5) Ethyl acetate 20%.

The pressure sensitive adhesive tape is suitable for a base film having a thickness of 6 um, a base film of polyester, a polyurethane pressure sensitive adhesive, and a thickness of 15 um.

As shown in FIG. 1 , the method for manufacturing the heat-expanding and loss-sensitive pressure-sensitive adhesive tape described in the present application sequentially passes through a rubber compounding zone 1 , a transfer blade coating machine 2 , and a film unwinding zone to be coated 3 . The baking oven area 4, the bonding bottom film unwinding area 5, the bottom film and the tape bonding roll area 6, the semi-finished winding area 7 after the bottom film is attached, and the film curing area 8 include the following steps:

A, a polyurethane pressure sensitive adhesive, an azo compound, an isocyanate curing agent, titanium cyan, ethyl acetate mixed in the above ratio, and stirred at a speed of 600r / min under a high speed mixer for 15min, to obtain an adhesive;

B, the coater oven temperature is set at 60 ° C;

C, the evenly mixed adhesive is coated on the base film corona surface by a coater, the coating speed is 5 m / min, the coating thickness is 15 um, dried by an oven, the baking time is 3 min, and the temperature is 60 ° C;

D. The dried adhesive is attached to the release surface of the 16 um PET release film at the bonding device of the coater;

E. Winding the bonded adhesive tape;

F. The expansive adhesive tape is obtained by placing the collected film at a temperature of 50 ° C for 48 hours.

As shown in FIG. 2, in the application of the present invention, the heat-expanding and loss-sensitive pressure-sensitive adhesive tape film is attached to the bottom film, and the cut release film 10 is attached to the base film 9.

Embodiment 2

1) Epoxy pressure sensitive adhesive 66%;

2) benzenesulfonyl hydrazide 15%;

3) amino resin curing agent 1%;

4) titanium dioxide 3%;

5) Butyl acetate 15%.

The base film of the heat expansion and loss-insensitive pressure-sensitive adhesive tape is 36 μm thick, and the base film is a polyimide film with a thickness of 50 μm.

The method for manufacturing the above-mentioned heated expansion and loss-loss type pressure-sensitive adhesive tape comprises the following steps:

A. The epoxy pressure sensitive adhesive, the benzenesulfonyl hydrazide, the amino resin curing agent, the titanium dioxide and the butyl acetate are mixed according to the above ratio, and stirred at a speed of 1500 r/min for 15 min under a high speed mixer to obtain an adhesive. ;

B, the coater oven temperature is set at 100 ° C;

C, the evenly mixed adhesive is coated on the base film corona surface by a coater, the coating speed is 30 m / min, the coating thickness is 70 um, dried by an oven, the baking time is 1 min, and the temperature is 120 ° C;

D. attaching the dried adhesive to the release surface of the 50 um OPP release film at the bonding device of the coater;

E. Winding the bonded adhesive tape;

F. The film is placed at a temperature of 50 ° C for 24 hours to obtain a heat-expandable and loss-sensitive pressure-sensitive adhesive tape.

Embodiment 3

1) polyester pressure sensitive adhesive 50%;

2) carbonate compound 30%;

3) Aziridine curing agent 1%;

4) cobalt green 3%;

5) Toluene 16%.

Further, the base film suitable for the heat expansion and lossless pressure-sensitive adhesive tape is a polyolefin film having a thickness of 20 μm and a thickness of 30 μm.

A, the polyester pressure sensitive adhesive, carbonate compound, aziridine curing agent, cobalt green and toluene were mixed according to the above ratio, and stirred at a speed of 800 r / min under a high speed mixer for 30 min to obtain an adhesive;

B, the coater oven temperature is set at 90 ° C;

C, the evenly mixed adhesive is coated on the base film corona surface by a coater, the coating speed is 20 m / min, the coating thickness is 40 um, dried by an oven, the baking time is 2 min, and the temperature is 60 ° C;

D. The dried adhesive is attached to the release surface of the 30 um PET release film at the bonding device of the coater;

E. Winding the bonded adhesive tape;

F. The film is placed at a temperature of 40 ° C for 36 hours to obtain a heat-expandable and loss-sensitive pressure-sensitive adhesive tape.

The heat expansion and debonding pressure-sensitive adhesive tape described in the application of the invention has stable viscosity at normal temperature, and has low viscosity after baking at high temperature, no residue on the adherend without residue, easy to remove, and solves the heating and expansion of the tape. The consistency and regularity of the rear curl direction greatly improve the production efficiency and increase the capacitance of the lithium battery Quantity, reduce battery space.

It should be understood that the above is not a limitation of the technical solution. In fact, the improvements, equivalent changes and modifications of the technical solutions under the same or similar principles are still claimed in the application of the present application. Technical solution.

Claims

A heat-expanding, loss-adhesive pressure-sensitive adhesive tape characterized by being made of the following mass percentage components:

1) pressure sensitive adhesive 40.4% ~ 66%;

2) The heat-expandable polymer material is 15.5% to 33.5%;

3) cross-linking agent 0.8% to 1.6%;

4) inorganic fillers 2.7% to 4.5%;

5) The organic solvent is 15% to 20%.
The heat-expandable, loss-adhesive pressure-sensitive adhesive tape according to claim 1, wherein said pressure-sensitive adhesive has a thickness of 15 to 70 μm.
The heat-expandable, loss-adhesive pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive or a rubber-type pressure-sensitive adhesive.
The heat expansion and debonding pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the inorganic filler is titanium dioxide, fumed silica, titanium cyan, carbon black, cobalt blue. , a mixture of one or two of cobalt green or graphite.
The heat-expandable, loss-insensitive pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the heat-swellable polymer material is a physical expansion microsphere, an azo compound, or a sub A mixture of one or both of a nitro compound, a sulfonyl hydrazide compound or a carbonate compound.
The heat-expandable, loss-adhesive pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the organic solvent is one or both of ethyl acetate, butyl acetate and toluene. mixing.
The heat-expandable, loss-adhesive pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the crosslinking agent is an isocyanate curing agent, an amine curing agent, an amino resin curing agent, and nitrogen. A mixture of one or both of the propidium curing agents.
A method of manufacturing a heat-expandable, loss-adhesive pressure-sensitive adhesive tape according to claim 1, comprising the steps of:

A. The pressure sensitive adhesive, the heat-sensitive expansion polymer material, the crosslinking agent, the inorganic filler, and the organic solvent are mixed according to the above ratio, and stirred at a speed of 600 to 1500 r/min under a high speed mixer for 15 to 40 minutes to obtain an adhesive. Agent

B, the oven or knife coater oven temperature is set between 60 ~ 120 ° C;

C. The evenly mixed adhesive is coated on the base film corona surface by a coating machine at a coating speed of 5 to 30 m/min, a coating thickness of 15 to 70 um, and dried by an oven, and the baking time is 1 to 3 minutes. , the temperature is 60-120 ° C;

D. The dried adhesive is applied to the release surface of the 16-50 um PET release film at the bonding device of the coater, and other release films such as OPP and PP;

E. Winding the bonded adhesive tape;

F. The film is placed at a temperature of 30 to 70 ° C for 24-48 hours to obtain a heat-expandable and loss-sensitive pressure-sensitive adhesive tape.