Release soft substrate and manufacturing method thereof

[0031] Example 1

[0032] The releasable flexible substrate of the present invention is prepared and the manufacturing method thereof.

[0033]

[0034] Preparation of the first polyamic acid solution

[0035] Put 52.63 grams of ODA and 440 grams of DMAc as a solvent into a three-necked flask, and after stirring it to completely dissolve, add 57.4 grams of PMDA, wherein the monomer accounts for 20 wt% of the total weight of the reaction solution. Then, continue stirring and react for 25 hours at 25° C., after the reaction is completed, 2 wt% of the silane compound and 20 wt% of the fluorine-containing filler are added to obtain the first polyamic acid solution.

[0036] Preparation of the second polyamic acid solution

[0037] 71.67 grams of TFMB and 412.5 grams of solvent DMAc were put into a three-necked flask, and after stirring them until they were completely dissolved, 65.84 grams of BPDA was added, in which monomers accounted for 25% by weight of the total weight of the reaction solution. Then, continue to stir and react for 25 hours at 25° C. to obtain the second polyamic acid solution.

[0038] Polyimide layer preparation

[0039] The obtained first polyamic acid solution was coated on a glass substrate, and heated in an oven at 80°C for about 30 minutes to remove most of the solvent, and then the above-mentioned first polyamic acid solution coated The glass substrate is placed in an oven at 170°C to 370°C and heated for about 4 hours to form a release layer. Coat the second polyamic acid solution on the release layer and put it in an oven at 80°C for heating for about 30 minutes, and then put the glass substrate coated with the second polyamic acid solution in an oven at 170°C to 370°C Inside, heating for about 4 hours to dry the polyamic acid solution into a polyimide layer. The peel strength between the polyimide layer and the release layer is less than 0.1 kgf/cm, and the polyimide layer 14 can be peeled from the release layer 12. The adhesion strength test between the release layer 12 and the glass substrate 10 was 5B.

[0040] Then the strength test

[0041] Use a hundred-grid knife to test the bonding strength. The test method is as follows. Prepare a polyimide film with a length of 5cm and a width of 5cm. Use a 100-grid squeegee and the tip of the knife to cut out a cross grid pattern on the coating surface, cut to the base material, and form 100 small grids in the middle, each grid 1mm long. 1mm wide. Then use a brush to brush the painted surface five times in a diagonal direction to gently clean the painted surface and the concave surface. Finally, use standard tape (3M Transparent Tape 600 or 610) to stick to the surface of 100 cells. Use one end of an eraser (for example, use a pencil with an eraser at one end) to press the surface to make the tape completely fit and flat, and instantly move 180° Tear the tape. The judgment method uses ASTM D3359-95, 5B: the edge of the cut is completely smooth, and there is no peeling on the edge of the grid. 4B: There is a small piece of peeling at the intersection of the cuts, and the actual damage in the grid area is ≤5%. 3B: The edges and/or intersections of the cuts are peeled off, and the area is greater than 5% to 15%. 2B: A part or a large piece of peeling off along the edge of the cut, or a part of the grid is peeled off entirely. The peeling area exceeds 15% to 35%. 1B: Large pieces of peeling off the edge of the cut/or partial or complete peeling of some squares, with an area larger than 35% to 65% of the grid area. 0B: There are pieces of paint peeling off at the edges and intersections of the scribe lines, and the total peeling area is greater than 65%. In the present invention, 5B is defined as the basic requirement of bonding strength.

[0042] Example 2

[0043] The steps of Example 1 are repeated, but the components of the first polyamic acid solution are changed to 5 wt% silane compound and 20 wt% fluorine-containing filler.

[0044] Example 3

[0045] The steps of Example 1 are repeated, but the components of the first polyamic acid solution are changed to 5 wt% silane compound and 5 wt% fluorine-containing filler.