TW202115211A - Thermal strippable pressure-sensitive adhesive sheet for wet and high temperature process which includes a polyimide base material, and a thermal expandable pressure-sensitive adhesive layer containing a heat-resistant adhesive and a thermal expandable sphere distributed in the heat-resistant adhesive - Google Patents

Abstract

The present invention relates to a thermal strippable pressure-sensitive adhesive sheet for wet and high temperature process, in particular to an adhesive sheet used for sticking to an adherend that requires wet and high temperature process, and includes: a polyimide base material, and a thermal expandable pressure-sensitive adhesive layer which is coated on at least one side of the polyimide base material, wherein the thermal expandable pressure-sensitive adhesive layer contains a heat-resistant adhesive and a thermal expandable sphere distributed in the heat-resistant adhesive. The total volume of the thermal expandable sphere accounts for 5-10 vol% of the adhesive layer, and the thickness of the thermal expandable pressure-sensitive adhesive layer needs to be greater than or equal to the diameter of the thermal expandable sphere, so that after the thermal strippable pressure-sensitive adhesive sheet is subjected to a wet and high temperature process, the adhesive force between the adherend and the thermal strippable pressure-sensitive adhesive layer is less than 0.1 gf/inch.

Description

Heat-peelable pressure-sensitive adhesive sheet for wet, high-temperature manufacturing process

The present invention relates to a heat-peelable pressure-sensitive adhesive sheet used in wet, high-temperature manufacturing processes, and particularly refers to a heat-peelable pressure-sensitive adhesive sheet that can be easily peeled from the adherend by short-term heating, and it will not be used in the wet process after the wet process. Liquid infiltration causes pollution and premature peeling of adherends.

In the prior art, high temperature resistant adhesive materials such as high temperature resistant adhesive sheets have been widely used in the production process of various fields (for example, semiconductors, semiconductor packages, LEDs, flexible, rigid, or rigid-flex circuit boards). For example, as an adhesive sheet for LED die CSP (chip size level packaging), by using an adhesive sheet to assist high-temperature (150°C~180°C) CSP packaging, the adhesive strength of the adhesive sheet during the LED packaging work It must be sufficient to fix the LED die to each other without being separated from the LED die, that is, no peeling occurs. In addition, after the LED die is packaged, in the step of removing it, it is necessary to separate the adhesive sheet from the LED die. Therefore, the adhesive sheet used in the production process of the LED die CSP needs to have both good adhesion and easy peeling characteristics after processing.

In the existing adhesive sheet products, for example, in the LED application field, after the required manufacturing process, such as high-temperature molding process, the adhesive force between the adhesive sheet and the object to be adhered will increase. In order to solve this problem, the conventional technology uses a heat-peelable pressure-sensitive adhesive sheet to overcome the problem of difficult removal. In order to increase the extraction efficiency of the LED light, the LED After epitaxy, a wet chemical etching process is introduced. Generally, a heat-peelable pressure-sensitive adhesive sheet is used. If the heat-expandable sphere is in the glue Improper control of the amount of addition may cause problems such as poor adhesion during the wet process, causing the liquid used in the wet process to penetrate between the adhesive sheet and the object to be attached, contaminating the product or causing the adhesive sheet to fall off.

Therefore, in the prior art, there is still room for improvement in adhesive sheets used in high-temperature, wet processes.

The heat-peelable pressure-sensitive adhesive sheet of the present invention used in wet and high-temperature manufacturing processes is used to adhere to an adherend that requires wet and high-temperature manufacturing processes, and includes: a polyimide substrate; And a heat-expandable pressure-sensitive adhesive layer, which is coated on at least one side of the polyimide substrate, and includes heat-resistant glue and heat-expandable spheres distributed in the heat-resistant glue, the total volume of the heat-expandable sphere It occupies 5-10 vol% of the adhesive layer, and the thickness of the heat-expandable pressure-sensitive adhesive layer must be greater than or equal to the diameter of the heat-expandable microsphere, so that the peelable pressure-sensitive adhesive sheet undergoes a wet, high-temperature manufacturing process. The adhesive force with the heat-expandable pressure-sensitive adhesive layer is less than 0.1gf/inch.

If so, the heat-peelable pressure-sensitive adhesive sheet of the present invention used in wet and high-temperature processes can be easily peeled from the adherend by short-term heating, and there will be no wet-type liquid infiltration to cause pollution and pollution through the wet process. The adherent is stripped early.

10‧‧‧Adhesive

12‧‧‧Polyimide substrate

14‧‧‧Heat-expandable pressure-sensitive adhesive layer

16‧‧‧Pressure Sensitive Adhesive

18‧‧‧Thermally expandable sphere

Figure 1 is a schematic diagram of the heat-peelable pressure-sensitive adhesive sheet used in the wet, high-temperature process of the present invention.

Figure 2 is the first schematic diagram of the use state of the heat-peelable pressure-sensitive adhesive sheet used in the wet, high-temperature process of the present invention.

Fig. 3 is a second schematic diagram of the use state of the heat-peelable pressure-sensitive adhesive sheet used in the wet, high-temperature process of the present invention.

Please refer to Figures 1 to 3, the present invention is a heat-peelable pressure-sensitive adhesive sheet for wet, high-temperature processing, which is used to adhere to an adherend 10 that requires wet, high-temperature processing , Which includes a polyimide substrate 12 and a heat-expandable pressure-sensitive adhesive layer 14.

The heat-expandable pressure-sensitive adhesive layer 14 is coated on at least one side of the polyimide substrate 12, and includes a pressure-sensitive adhesive 16 and heat-expandable spheres 18 distributed in the pressure-sensitive adhesive 16. The total volume of the heat-expandable sphere 18 occupies 5-10 vol of the pressure-sensitive adhesive 16, and the thickness of the heat-expandable pressure-sensitive adhesive layer 14 must be greater than or equal to the diameter of the heat-expandable sphere 18, so that the heat-expandable pressure-sensitive adhesive layer 14 can be effectively adhered to On the adherend 10, after the peelable pressure-sensitive adhesive sheet undergoes a wet, high-temperature process, the adhesive force between the adherend 10 and the heat-expandable pressure-sensitive adhesive layer 14 is less than 0.1gf/inch, so that it can be easily peeled off without liquid leakage phenomenon.

The composition of the pressure-sensitive adhesive 16 can be selected from traditional pressure-sensitive adhesive systems with relatively heat-resistant formulations, such as rubber-based pressure-sensitive adhesive sheets, acrylic-based pressure-sensitive adhesive sheets, and vinyl-alkyl ether-based pressure-sensitive adhesive sheets , Polysiloxane pressure sensitive adhesive sheet, polyester pressure sensitive adhesive sheet, polyamide pressure sensitive adhesive sheet, urethane pressure sensitive adhesive sheet, polystyrene/diene copolymer pressure sensitive adhesive sheet.

The thermally expandable sphere 18 can be manufactured using a conventional method, for example, agglomeration or interfacial polymerization. The heat-expandable microspheres also include commercially available heat-expandable microspheres, for example, MICROSPHRERE ^TM (manufactured by Matsumoto Yushi Seiyaku KK), which can be easily heated to vaporize and expand. .

When the heat-peelable pressure-sensitive adhesive sheet is adhered to the adherend 10 and subjected to a wet and heating process, there will be no seepage between the peelable pressure-sensitive adhesive sheet and the adherend 10, causing pollution and early peeling of the adherend This phenomenon, and the adhesive force between the adherend 10 and the heat-expandable pressure-sensitive adhesive layer 14 is less than 0.1 gf/inch, so that the adherend 10 can be easily peeled off.

Description of Examples and Comparative Examples

Example 1

Take a container of 250ml, pour a heat-resistant acrylic adhesive such as HT-6555-1 50g (purchased from Taiwan Xinzong Industrial Co., Ltd.), and add crosslinking agent N 0.1g (from Taiwan Xinzong Industrial Co., Ltd.) Co., Ltd.) stir uniformly for 10 minutes, add 0.64g of heat-expandable sphere (model: FN-190SSD, purchased from Matsumoto Oils and Fats, Japan) for 20 minutes, then use a spatula to coat a polyimide substrate (model : TL-025, obtained from Taiwan Damai Technology), placed in an oven at 100℃/30min to remove the solvent, take out the sample to cover the release film and then mature at 50℃/24hr.

Example 2

Same as Example 1, but the added heat-expandable sphere is changed to 0.896g.

Example 3

Same as Example 1, but adding heat-expandable spheres to 1.28g.

Comparative example 1

Same as Example 1, but without adding thermally expandable spheres.

In Comparative Example 2, the addition of thermally expandable spheres was changed to 0.512 g.

In Comparative Example 3, the addition of thermally expandable spheres was changed to 1.536 g.

Same as Example 1, but adding heat-expandable spheres to 1.34g.

Result evaluation method

Adhesion test method

Cut the above-mentioned adhesive sheet into a width of 1 inch (inch) and a length of 150 millimeters (mm), and use a 2 kilogram (kg) roller to attach it to a mirror-finished steel plate at 23°C (at room temperature) on. The polished steel plate is cleaned with a dust-free cloth moistened with alcohol and acetone and left for 1 hour before use. Select the appropriate temperature, heat source and time to heat to cause the heat-expandable sphere in the heat-expandable pressure-sensitive adhesive layer 2 to expand (for example: in the embodiment, the heat-expandable sphere is selected. Model: FN-190SSD. For temperature selection, please refer to Japan Matsumoto Grease Type The recorded maximum expansion temperature was heated with a hot plate for 300 seconds); after that, the adhesive sheet attached to the polished steel plate was peeled at a peeling speed of 300mm/min and a peeling angle of 180 degrees, and the adhesive force was measured (unit: gf) /1inch).

Red ink test method

The prepared adhesive sheet was cut into an area of 25 cm ² , and it was attached to the glass at 23° C. (at room temperature) with a 2 kilogram (kg) roller. The glass is a brand-new product that has just been opened, cleaned with a dust-free cloth moistened with alcohol and acetone and left for 1 hour before use.

Subsequent to soak the whole in the red potion, and then put it in an Ultrasonic cleaner (Ultrasonic cleaner) to shake for a period of time, so that the red potion can evenly penetrate into the depths of all the gaps, and then take it out and bake at 100℃/1hr. Bake, and then clamp the sample to be tested in the jig, and then use a general high-power optical microscope to observe the degree of staining.

Table Description of Examples and Comparative Examples

The content of the above specific embodiments is to describe the present invention in detail. However, these embodiments are for illustration only and are not intended to limit the present invention. Those who are familiar with the art in the field can understand that the present invention is directed to the present invention without departing from the scope defined by the appended patent application. Various changes or modifications made fall into a part of the present invention.

10‧‧‧Adhesive

12‧‧‧Polyimide substrate

14‧‧‧Heat-expandable pressure-sensitive adhesive layer

16‧‧‧Pressure Sensitive Adhesive

18‧‧‧Thermally expandable sphere

Claims (3)

A heat-peelable pressure-sensitive adhesive sheet used in wet and high-temperature manufacturing processes, which is used to adhere to an adherend that requires wet and high-temperature manufacturing processes, and includes; a polyimide substrate; and A heat-expandable pressure-sensitive adhesive layer, which is coated on at least one side of the polyimide substrate, and includes a pressure-sensitive adhesive and heat-expandable spheres distributed in the pressure-sensitive adhesive. The total volume of the heat-expandable sphere occupies 5-10 vol% of the adhesive layer, and the thickness of the heat-expandable pressure-sensitive adhesive layer must be greater than or equal to the diameter of the heat-expandable sphere, so that the peelable pressure-sensitive adhesive sheet is subjected to wet and high-temperature processes. The adhesion between the adherend and the heat-expandable pressure-sensitive adhesive layer is less than 0.1 gf/inch. The heat-peelable pressure-sensitive adhesive sheet for wet and high-temperature processes as described in claim 1, wherein the pressure-sensitive adhesive can be selected from rubber-based pressure-sensitive adhesive sheets, acrylic-based pressure-sensitive adhesive sheets, vinyl Base-alkyl ether-based pressure-sensitive adhesive sheet, silicone-based pressure-sensitive adhesive sheet, polyester-based pressure-sensitive adhesive sheet, polyamide-based pressure-sensitive adhesive sheet, urethane-based pressure-sensitive adhesive sheet, polyphenylene Ethylene/diene copolymer series pressure sensitive adhesive sheet. The heat-peelable pressure-sensitive adhesive sheet for wet, high-temperature manufacturing processes as described in claim 1, wherein the heat-expandable microsphere system is one that can be easily heated to vaporize and expand.

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