KR20220122266A - Manufacturing method of Flexible Flat Cable or Flexible Printed Circuit capable of spontaneous double side etching and composition of double sided tape for double side etching - Google Patents

Abstract

The present invention relates to a manufacturing method of a flexible flat cable (FFC) or a flexible printed circuit (FPC) capable of spontaneous double side etching and a composition of a double-sided adhesive tape for double side etching for implementing the same. More specifically, the method comprises: a step of laminating a soft copper laminate on both sides of the double-sided adhesive tape; a step of manufacturing the FFC or the FPC by using the soft copper laminate through a common manufacturing process; and a step of removing the double-sided adhesive tape. A plurality of FFCs or FPCs can be manufactured at the same time.

Description

Manufacturing method of flexible flat cable or flexible printed circuit capable of double-sided simultaneous etching, and double-sided adhesive tape composition for realizing the same for double side etching}

The present invention relates to a method for manufacturing a flexible flat cable (FFC) or flexible printed circuit (FPC) capable of double-sided simultaneous etching and a double-sided adhesive tape composition for double-sided etching for realizing the same, improving productivity For this purpose, double-sided adhesive tape for double-sided etching is interposed between copper foils so that both sides can be etched at the same time.

In the recent electronics industry, with the development of circuit integration, miniaturization of parts (chip parts), and the development of surface mount technology to mount them, flexible printed circuits that can be easily embedded in a narrow space and these surface-mounted flexible printed circuits are mutually exclusive. A flexible flat cable that connects has been developed and is being widely used throughout the electronics industry, such as portable terminals and various displays. In general, the process of manufacturing a flexible printed circuit and a flexible flat cable is as follows.

Flexible Copper Clad Laminate (FCCL), which is a basic material, and films such as Polyimide (PI), Polycyclohexylenedimethylene terephthalate (PCT), and Polyethylene naphthalate (PEN) used as insulating layers are laminated on top of the flexible copper laminate. It is formed by plating a copper thin film layer on the As shown in FIG. 1 as a pretreatment process, the lamination process is a rate-limiting process.

After attaching a dry film, which is a photoreceptor, to exposure by covering a mask printed with circuitry, an etchant is sprayed to corrode and remove unnecessary parts to form a circuit, and then remove the dry film, wash and dry the etching process to finish

Thereafter, a flexible printed circuit or flexible flat cable may be manufactured by laminating an insulating film having a material such as polyimide (PI), polycyclohexylenedimethylene terephthalate (PCT), or polyethylene naphthalate (PEN) as described above. As shown in FIG. 1 as a finishing process, the lamination process is a rate-limiting process.

However, as can be seen through the manufacturing process, productivity is reduced by consuming most of the manufacturing time in the lamination process performed in the pre-treatment and finishing steps rather than the process of manufacturing the actual circuit by printing, and such a lamination process There is a problem in that over-investment of equipment to reduce the bottleneck of the following process occurs.

Republic of Korea Patent No. 1831298

The present invention has been devised in order to solve the problems of the prior art as described above, and the present invention is made by interposing a double-sided adhesive tape that is resistant to etching solution and can be easily peeled off by physical treatment after manufacturing between the flexible copper laminates. can omit the pretreatment process (insulation film lamination process) of The purpose of the present invention is to provide a process capable of manufacturing a flexible printed circuit or flexible flat cable capable of dividing the rate-limiting process time in half by simultaneously laminating them.

Another object of the present invention is to provide a composition of a double-sided tape that is resistant to the etching solution and can be easily peeled off by physical treatment.

The present invention comprises the steps of laminating a flexible copper laminate on both sides of a double-sided adhesive tape in order to achieve the above object; manufacturing a flexible flat cable or a flexible printed circuit through a conventional manufacturing process using the flexible copper laminate; and peeling off the double-sided adhesive tape. It provides a method of manufacturing a flexible flat cable or flexible printed circuit, characterized in that it is possible to simultaneously manufacture a plurality of the flexible flat cable or flexible printed circuit.

The step of peeling the double-sided adhesive tape is preferably performed by foaming the double-sided adhesive tape.

During the foaming, heating is performed, and the foaming temperature by heating is preferably in the range of 80 to 180°C.

During the foaming, heating is performed, and the foaming time by heating is preferably in the range of 20 seconds to 30 minutes.

In addition, the present invention provides a composition for a double-sided adhesive tape for manufacturing a flexible flat cable or flexible printed circuit, comprising: a polymer obtained by mixing at least one type of acrylic monomer and at least one type of saturated or unsaturated hydrocarbon monomer or oligomer; and at least one physical, organic or inorganic foaming agent; provides a composition for a double-sided adhesive tape comprising a.

It is preferable that the said acrylic monomer has a structure of following formula (1).

[Formula 1]

Here, R ₁ is hydrogen (H) or a methyl group (-CH ₃ ), R ₂ and R ₃ are each hydrogen (H) or a hydrocarbon having 1 to 12 carbon atoms, and R ₄ is a hydrocarbon having 1 to 18 carbon atoms.

The content of the acrylic monomer is preferably 1 to 40% by weight based on the total weight of the composition.

The unsaturated hydrocarbon is preferably at least one selected from butadiene and isoprene.

The content of the unsaturated hydrocarbon is preferably greater than 0 and 30% by weight or less based on the total weight of the composition.

The saturated or unsaturated hydrocarbon oligomer is preferably at least one selected from aromatic or aliphatic petroleum resins.

The saturated or unsaturated hydrocarbon oligomer is preferably greater than 0 and 10 wt% or less based on the total weight of the composition.

The physical foaming agent has a spherical core-shell structure composed of a polymer wall material and an inner core filled with a volatile foaming agent, and preferably includes at least one different particle size or foaming temperature.

The organic blowing agent is benzenesulfonylhydrazide (Benesulfonylhydrazide), para-toluenesulfonylhydrazide (p-Toluenesufonylhydrazide) or para, para-oxybis (benzenesulfonylhydrazide) (p,p'-oxybis (benzenesulfonylhydrazide)) in It is preferable that it is at least 1 sort(s) chosen.

The inorganic foaming agent is preferably at least one selected from sodium bicarbonate (NaHCO ₃ ) or potassium bicarbonate (KHCO ₃ ).

It is preferable that at least one of the physical, organic and inorganic foaming agents is alone or in a combined weight of 5 to 30% by weight based on the total weight of the composition.

According to the present invention as described above, the printed circuit is manufactured on both sides by performing double-sided etching after interposing a foamable double-sided adhesive tape between two flexible copper laminates, and at the same time by peeling the double-sided adhesive tape by foaming, the printed circuit Two sheets can be produced, and the production time can be divided in half by simultaneously performing the lamination process of the film used as the insulating layer on both sides, thereby improving the productivity by about 4 times.

1 is a comparative view of a laminating process for manufacturing a conventional flexible printed circuit or flexible flat cable and a laminating process according to the present invention.
2 is an enlarged photograph of the surface after the etch resistance test for Example 1 of the present invention.
3 is an enlarged photograph of the surface after an etch resistance test for a comparative example.
4 is a photograph of 10 seconds, 30 seconds, and 60 seconds of the etching resistance test for Example 1 of the present invention, respectively.
5 is a photograph of 10 seconds, 30 seconds, and 60 seconds of the etching resistance test for Example 2 of the present invention, respectively.
6 is a photograph of 10 seconds, 30 seconds, and 60 seconds of the etching resistance test for Example 3 of the present invention, respectively.
7 is a photograph of 10 seconds, 30 seconds, and 60 seconds of the etch resistance test for Comparative Example 3, respectively.
8 is a photograph in which the etch resistance test for Example 4 of the present invention was performed for 10 seconds, 30 seconds, and 60 seconds, respectively.
9 is a photograph in which the etch resistance test for Example 5 of the present invention was performed for 10 seconds, 30 seconds, and 60 seconds, respectively.
10 is a photograph in which the etch resistance test for Example 6 of the present invention was performed for 10 seconds, 30 seconds, and 60 seconds, respectively.

Hereinafter, the present invention will be described in more detail based on the accompanying drawings and preferred embodiments.

The present invention is a step of laminating a flexible copper laminate on both sides of a double-sided adhesive tape, manufacturing a printed circuit through a conventional series of manufacturing processes, and peeling the printed circuit formed on both sides of the double-sided adhesive tape by a physical method in the peeling process It provides a method of manufacturing a flexible flat cable or flexible printed circuit, characterized in that it is possible to simultaneously manufacture a plurality of printed circuits including the step, for example, two. This is as shown in the lower part of FIG. 1 .

In addition, the double-sided adhesive tape is a polymer polymerized from a mixture containing at least one kind of acrylic monomer, at least one kind of saturated or unsaturated hydrocarbon monomer or oligomer, and at least one kind of physical, organic or inorganic foaming agent is added. It provides a double-sided adhesive tape composition characterized in that it becomes.

As mentioned in the background art, the above series of manufacturing processes refers to the processes of flexible flat cables or flexible printed circuits currently mass-produced, and the physical method in the peeling process is manufactured by reducing the contact area by foaming at a certain temperature It refers to the method of peeling the printed circuit without deformation or damage.

The foaming process is performed in a heated environment, and it is preferable that the temperature during heating is 80 ° C or more and 180 ° C or less, where the foaming temperature is 80 ° C or less, the foaming agent is pre-foamed in the etching process, and the above object cannot be achieved, and 180 ° C. When foaming at an abnormally high temperature, the performance of the circuit formed by the oxidation of copper deteriorates, so the foaming temperature has a critical significance in the above range.

In addition, the foaming time is preferably 20 seconds or more and 30 minutes or less, and if it is 20 seconds or less, the contact area is not sufficiently small due to insufficient foaming, so there is little decrease in adhesive strength. In the case of abnormality, since the foamed double-sided tape reflows over time at high temperature and the adhesive strength increases again by increasing the contact area, this may also be deformed when the printed circuit formed on both sides is removed. There is a critical significance in the above range.

On the other hand, in order to manufacture a flexible flat cable or flexible printed circuit through the above manufacturing process, there should be no inflow of etching solution through the interface between the double-sided adhesive tape and the flexible copper laminate. If the etchant flows into the interface, not only the rear surface is oxidized, but the side surface is overetched, which may cause product defects.

Therefore, in order to solve the above problems, a method of increasing the wettability of the interface by lowering the secondary transition temperature (glass transition temperature, Tg) of the pressure-sensitive adhesive or improving the adhesion with the flexible copper laminate can be considered, but both methods are excessive. Since the decrease in adhesive strength is small even after foaming due to the initial adhesive strength, it is impossible to avoid deformation of the printed circuit formed on both sides during peeling, the problem still exists.

Accordingly, the present inventors have achieved the above object by including at least one acrylic monomer having a structure of the following formula (1) in the polymer, paying attention to that the basic material can effectively block the acidic etchant.

[Formula 1]

Here, R ₁ is hydrogen (H) or a methyl group (-CH ₃ ), R ₂ and R ₃ are each hydrogen (H) or a hydrocarbon having 1 to 12 carbon atoms, and R ₄ is a hydrocarbon having 1 to 18 carbon atoms.

The content of the acrylic monomer having the structure of Formula 1 is preferably 1 wt% or more and 40 wt% or less based on the total weight of the composition. The above weight % range has a critical significance because it cannot be used as an adhesive by coagulating with each other due to the difference.

The unsaturated hydrocarbon contained in the polymer may be used individually or in combination with butadiene or isoprene, and the unsaturated hydrocarbon is preferably used in an amount of 30% by weight or less based on the total weight of the composition in order to control the secondary transition temperature, and use more Since phase separation is caused due to the polarity difference with the compound of Formula 1, the above numerical value has critical significance.

In addition, in the composition, the saturated or unsaturated hydrocarbon oligomer used to adjust the adhesive force of the pressure-sensitive adhesive may be added by selecting at least one selected from aromatic or aliphatic petroleum resins, and the content is preferably 10% by weight or less and more than that. Excessive adhesive force makes it impossible to achieve the above object. Therefore, the above figure has critical significance.

In the composition, the physical foaming agent has a spherical core-shell structure consisting of a polymer wall material and a core filled with a volatile foaming agent, and at least one physical foaming agent having a different particle size or foaming temperature. includes In the composition, the organic foaming agent includes benzenesulfonylhydrazide, p-Toluenesufonylhydrazide, or para, para-oxybis (benzenesulfonylhydrazide) (p,p'-oxybis(p,p'-oxybis( Among benzenesulfonylhydrazide)), at least one organic foaming agent having a different particle size or foaming temperature may be included. In the composition, the inorganic foaming agent may include at least one inorganic foaming agent having a different particle size or foaming temperature among sodium bicarbonate (NaHCO ₃ ) or potassium bicarbonate (KHCO ₃ ).

The above foaming agents may be used alone or in an amount of 5% by weight or more and 30% by weight or less based on the total weight of the composition by using at least one physical, organic, and inorganic foaming agent alone or in combination. When used in excess of 30% by weight, deformation of the printed circuit and reflow of the pressure-sensitive adhesive due to over-foaming can not be expected, so the desired reduction in adhesive strength cannot be expected.

Hereinafter, the present invention will be described in detail based on the accompanying drawings and embodiments. The present invention may be implemented in several different forms and is not limited to the embodiments described herein.

Example 1.

(1) In a 500ml flask, put 90g of 2-EHA (2-ethylhexyl acrylate), 6g of 2-HEA (2-hydroxyethyl acrylate), 24g of DMA (N,N'-dimethyl acrylamide) and 180g of EA (Ethylacetate) as a solvent. After stirring for 30 minutes while evacuating with nitrogen, 0.01 g of AIBN (Azobisisobutyronitrile) and 0.1 g of 1-dodecanethiol were added, and reacted at 60° C. for 8 hours (solid content 43%, conversion rate 97%).

(2) In 100 g of the polymerization solution, 6.45 g of physical foaming agent (average particle diameter: 16㎛, foaming temperature: 100~140℃) (15% of solid content) and 0.622g of curing agent (HDI, Hexamethylene Diisocyanate) (40 mol% of HEA) was added and stirred to prepare a solution for preparing a double-sided adhesive tape.

(3) The liquid was coated on both sides to a thickness of 50 μm on a 50 μm PET film, and then aged at 50° C. for 72 hours to prepare a double-sided adhesive tape.

(4) A flexible copper laminate sample for double-sided etching was prepared by laminating a 35 μm thick flexible copper laminate on both sides of the double-sided adhesive tape prepared in (3).

(5) Afterwards, the process was performed as follows to compare productivity.

1) A typical etching process was performed to compare the total manufacturing time.

2) The etch resistance was compared to the degree of deposition by washing and drying the flexible copper laminate for 10 seconds, 30 seconds, and 60 seconds in the etching solution.

Thereafter, the solid content of the compound was in the range of 40 to 43 wt%, and the conversion rate was in the range of 95 to 99%, and the quantitative additive was calculated based on the solid content and the conversion rate.

Comparative Example 1.

(1) A PEN film was laminated on the flexible copper laminate as an insulating layer and thermocompression-bonded at 150° C. for 1.5 hours to prepare a sample for etching.

(2) The effect of the present invention was compared by comparing the total manufacturing time by performing a conventional etching process on the prepared sample.

Comparative Example 2.

(1) Put 90 g of 2-EHA (2-ethylhexyl acrylate), 6 g of 2-HEA (2-hydroxyethyl acrylate), 24 g of MA (Methyl acrylate) and 180 g of EA (Ethylacetate) as a solvent in a 500 ml flask and evacuate with nitrogen 30 After stirring for minutes, 0.01 g of AIBN (Azobisisobutyronitrile) and 0.1 g of 1-dodecanethiol were added, followed by reaction at 60° C. for 8 hours. (solids 42%, conversion 98%)

(2) 6.3 g of physical foaming agent (average particle size: 16㎛, foaming temperature: 100~160℃) (15% of solid content) and 0.608g of curing agent (HDI, Hexamethylene Diisocyanate) (40 mol% of HEA) in 100 g of the polymerization solution was added and stirred to prepare a double-sided adhesive tape solution.

(3) The liquid was coated on both sides to a thickness of 50 μm on a 50 μm PET film, and then aged at 50° C. for 72 hours to prepare a double-sided adhesive tape.

(4) A flexible copper laminate sample for double-sided etching was prepared by laminating a 35 μm thick flexible copper laminate on both sides of the double-sided adhesive tape prepared in (3).

(5) After that, the soft copper laminate was immersed in the etching solution for 10 seconds, 30 seconds, and 60 seconds, washed and dried, and the etch resistance was compared to the degree of deposition.

Example 2

Mostly the same as in Example 1, except that the polymerization was performed using AN (Acrylonitrile) instead of DMA. The etch resistance was compared to the degree of deposition.

Example 3

Mostly the same as in Example 1, except that DAEA (N,N-dimethylaminoethyl acrylate) was used instead of DMA for polymerization, and the flexible copper laminate was immersed in an etchant for 10 seconds, 30 seconds, or 60 seconds, washed, dried and deposited The etch resistance was compared.

Comparative Example 3.

Mostly the same as in Example 1, except that 1% by weight of DMA was used and the remainder was polymerized using MA (Methyl acrylate), and the flexible copper laminate was immersed in the etching solution for 10 seconds, 30 seconds, and 60 seconds, followed by washing, The etch resistance was compared to the extent to which it was dried and deposited.

Example 4

Mostly the same as in Example 1, except that 10% by weight of DMA was used and the remainder was polymerized using MA (Methyl acrylate), and the flexible copper laminate was immersed in the etching solution for 10 seconds, 30 seconds, and 60 seconds, followed by washing, The etch resistance was compared to the extent to which it was dried and deposited.

Example 5.

Most of the same as in Example 1, but using 30% by weight of DMA and deducting the increased amount (10% by weight) from 2-HEA, polymerization was performed, and the flexible copper laminate was immersed in the etching solution for 10 seconds, 30 seconds, and 60 seconds. After washing and drying, the etch resistance was compared to the degree of deposition.

Example 6.

Mostly the same as in Example 1, but using 40% by weight of DMA and subtracting the increased amount (20% by weight) from 2-HEA to polymerize. After immersing the flexible copper laminate in the etching solution for 10 seconds, 30 seconds, and 60 seconds The etch resistance was compared to the degree of deposition after washing and drying.

Comparative Example 4.

It is the same as in Example 1 except that the amount of the foaming agent was added at 5% by weight relative to the solid content, and the etch resistance was compared to the extent that the soft copper laminate was immersed in the etchant for 10 seconds, 30 seconds, or 60 seconds, washed and dried, and deposited did.

Example 7.

The same as in Example 1 except that the amount of the foaming agent was added at 30% by weight relative to the solid content, and the etch resistance was compared to the extent that the flexible copper laminate was immersed in the etching solution for 10 seconds, 30 seconds, or 60 seconds, washed and dried. did.

As can be seen from the test result 1 below, the manufacturing time of the flexible flat cable or flexible printed circuit manufactured by the present invention is 61.5 minutes per sheet, and the manufacturing time of the product manufactured by the conventional method is 212 minutes per sheet, the present invention In the case of , a productivity improvement of about 3.5 times can be expected.

test result 1 division Example 1 Comparative Example 1 note pretreatment time 2 minutes 91 minutes Example: 1 minute each on both sides Comparative Example: 1 minute on one side + 90 minutes of thermocompression bonding Etching time 30 minutes 30 minutes Post-processing time 91 minutes 91 minutes Total Time 123 minutes 212 minutes number of production 2 sheets 1 sheet production time per sheet 61.5 minutes 212 minutes about 3.5 times

As can be seen from the test result 2 below, when a general double-sided adhesive is used, the etching solution seeps into the interface between the double-sided adhesive tape and the flexible copper laminate and corrodes the back of the flexible copper laminate, resulting in a short circuit or crushing of the printed circuit ( 3) the etch resistance is remarkably lowered, and therefore it must contain a basic compound.

test result 2 division Example 1 Comparative Example 2 note etch resistance 10 seconds ◎ X 30 seconds ◎ X 60 seconds ◎ X Photo Figure 2 Fig. 3

Very good ◎ / Excellent ○ / Average △ / Bad X

Looking at the test result 3 below, the basic compound is not limited in type, and as can be seen from the test result 4 below, if the content of the basic compound is below the critical value, the etchant acts as an interface between the double-sided adhesive tape and the flexible copper laminate. It permeates and corrodes the back surface of the flexible copper laminate, so it can be seen that the amount has a critical value.

test result 3 division Example 1 Example 2 Example 3 etch resistance 10 seconds ◎ ◎ ◎ 30 seconds ◎ ○ ◎ 60 seconds ◎ ○ ◎ Photo Fig. 4 Fig. 5 Fig. 6

Very good ◎ / Excellent ○ / Average △ / Bad X

test result 4 division etch resistance Photo 10 seconds 30 seconds 60 seconds Comparative Example 3 △ △ X Fig. 7 Example 4 ○ ○ △ Fig. 8 Example 1 ◎ ◎ ◎ Fig. 4 Example 5 ◎ ◎ ◎ Fig. 9 Example 6 ○ ○ ○ Fig. 10

Very good ◎ / Excellent ○ / Average △ / Bad X

As can be seen from Test Result 5 below, the amount of the foaming agent affects the peel strength after etching, and it is desirable that the peel strength be low.

test result 5 division Comparative Example 4 Example 1 Example 7 adhesiveness
(gf/in) before firing 1,291 327 80 after firing 258 0 0

Although the present invention has been described in more detail with reference to Examples above, the present invention is not necessarily limited to these Examples and various modifications may be made within the scope without departing from the spirit of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (15)

Laminating a flexible copper laminate on both sides of the double-sided adhesive tape;
manufacturing a flexible flat cable or a flexible printed circuit through a conventional manufacturing process using the flexible copper laminate; and
peeling the double-sided adhesive tape;
A method of manufacturing a flexible flat cable or flexible printed circuit, characterized in that it is possible to simultaneously manufacture a plurality of the flexible flat cable or flexible printed circuit. According to claim 1,
The step of peeling the double-sided adhesive tape; is a method of manufacturing a flexible flat cable or flexible printed circuit, characterized in that performed by foaming the double-sided adhesive tape. 3. The method of claim 2,
Heating is performed during the foaming, and the foaming temperature by heating is in the range of 80 to 180°C. 4. The method of claim 3,
During the foaming, heating is performed, and the foaming time by heating is in the range of 20 seconds to 30 minutes. A composition for double-sided adhesive tape for manufacturing flexible flat cables or flexible printed circuits,
a polymer obtained by mixing at least one acrylic monomer and at least one saturated or unsaturated hydrocarbon monomer or oligomer; and
at least one physical, organic or inorganic blowing agent;
A composition for double-sided adhesive tape comprising a. 6. The method of claim 5,
The acrylic monomer is a composition for a double-sided adhesive tape, characterized in that it has a structure of the following formula (1).
[Formula 1]

Here, R ₁ is hydrogen (H) or a methyl group (-CH ₃ ), R ₂ and R ₃ are each hydrogen (H) or a hydrocarbon having 1 to 12 carbon atoms, and R ₄ is a hydrocarbon having 1 to 18 carbon atoms. 7. The method of claim 5 or 6,
The composition for double-sided adhesive tape, characterized in that the content of the acrylic monomer is 1 to 40% by weight based on the total weight of the composition. 7. The method of claim 5 or 6,
The unsaturated hydrocarbon is a composition for a double-sided adhesive tape, characterized in that at least one selected from butadiene and isoprene. 9. The method of claim 8,
The composition for double-sided adhesive tape, characterized in that the content of the unsaturated hydrocarbon is more than 0 and 30% by weight or less based on the total weight of the composition. 7. The method of claim 5 or 6,
The saturated or unsaturated hydrocarbon oligomer is a composition for double-sided adhesive tape, characterized in that at least one selected from aromatic or aliphatic petroleum resin. 11. The method of claim 10,
The composition for double-sided adhesive tape, characterized in that the saturated or unsaturated hydrocarbon oligomer is more than 0 and 10% by weight or less based on the total weight of the composition. 7. The method of claim 5 or 6,
The physical foaming agent has a spherical core-shell structure consisting of a polymer wall material and a core filled with a volatile foaming agent, and comprises at least one type having a different particle size or foaming temperature. Composition for double-sided adhesive tape. 7. The method of claim 5 or 6,
The organic foaming agent is benzenesulfonylhydrazide (Benenesulfonylhydrazide), paratoluenesulfonylhydrazide (p-Toluenesufonylhydrazide) or para, para-oxybis (benzenesulfonylhydrazide) (p,p'-oxybis (benzenesulfonylhydrazide)) A composition for double-sided adhesive tape, characterized in that at least one selected. 7. The method of claim 5 or 6,
The inorganic foaming agent is sodium bicarbonate (NaHCO ₃ ) or potassium bicarbonate (Potassium bicarbonate: KHCO ₃ ) A composition for double-sided adhesive tape, characterized in that at least one selected from the group consisting of. 7. The method of claim 5 or 6,
At least one of the physical, organic and inorganic foaming agents is a composition for a double-sided adhesive tape, characterized in that the weight alone or the combined weight is 5 to 30% by weight based on the total weight of the composition.

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