METHOD FOR MANUFACTURING POLYIMIDE FILM WITH REDUCED GLOSS

Abstract

The present invention provides a method for manufacturing a polyimide film with a reduced gloss, which comprises providing a diamine and a diacid anhydride for polymerization in a solvent to form a polyimide precursor solution; adding 2-5 equivalents of a dehydrating agent and a catalyst into the polyimide precursor solution and then coating a carrier with the polyimide precursor solution to form a polyimide gel film; providing an embossing wheel to roll the polyimide gel film peeled from the carrier at a temperature of 140-200 C. and a pressure of 3-10 Kgf/cm.sup.2 to form a concave and convex shape on a surface of the polyimide gel film; and baking the polyimide gel film to form a polyimide film with a 60 gloss of less than 100 GUs.

Claims

1. A method for manufacturing a polyimide film with a reduced gloss, comprising: providing a diamine and a diacid anhydride for polymerization in a solvent to form a polyimide precursor solution, wherein the diamine includes 10-45 mol % of 4,4-diaminodiphenyl ether (4,4-ODA) and 90-55 mol % of p-phenylenediamine (p-PDA) based on a total amount of the diamine, the diacid anhydride includes 10-50 mol % of pyromellitic dianhydride (PMDA) and 90-50 mol % of 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA) based on a total amount of the diacid anhydride; adding 2-5 equivalents of a dehydrating agent and a catalyst into the polyimide precursor solution and then coating a carrier with the polyimide precursor solution to form a polyimide gel film, which has a Young's modulus of 230-350 Kgf/mm.sup.2, wherein the dehydrating agent is an aliphatic acid anhydride and/or an aromatic acid anhydride; providing an embossing wheel to roll the polyimide gel film peeled from the carrier at a temperature of 140-200 C. and a pressure of 3-10 Kgf/cm.sup.2 to form a concave and convex shape on a surface of the polyimide gel film; and baking the polyimide gel film to form a polyimide film with a 60 gloss of less than 100 GUs.

2. The method of claim 1, wherein a content of the solvent in the polyimide gel film is between 20 wt % and 40 wt %.

3. The method of claim 1, wherein a roller speed of the embossing wheel is between 1 m/min and 4 m/min.

4. The method of claim 1, wherein the embossing wheel is operated at a temperature of 140-180 C. and a pressure of 3-8 Kgf/cm.sup.2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a step diagram of a method for manufacturing a polyimide film with a reduced gloss according to the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0010] With reference to FIG. 1, which shows a method for manufacturing a polyimide film with a reduced gloss according to the present disclosure and includes the following steps.

[0011] A diamine and a diacid anhydride are provided for polymerization in a solvent to form a polyimide precursor solution (S1). Based on a total amount of the diamine, the diamine includes 10-45 mol % of 4,4-diaminodiphenyl ether (4,4-ODA) and 90-55 mol % of p-phenylenediamine (p-PDA). Based on a total amount of the diacid anhydride, the diacid anhydride includes 10-50 mol % of pyromellitic dianhydride (PMDA) and 90-50 mol % of 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA).

[0012] A dehydrating agent and a catalyst are added into the polyimide precursor solution. There are 2-5 equivalents of the dehydrating agent. The polyimide precursor solution is coated on a carrier to form a gel film (S2), which has a Young's modulus of 230-350 Kgf/mm2. A content of the solvent in the polyimide gel film is preferably 20-40 wt %.

[0013] Further, when the Young's modulus of the gel film is greater than 350 kgf/mm.sup.2, the surface of the gel film is relatively rigid. Under the same conditions, the concave and convex shape of the embossing wheel surface is not easily transferred to the gel film, and it is necessary to increase the pressure or temperature for smooth transfer. However, if the pressure or temperature during transfer is increased, the gel film will easily wrinkle and reduce production efficiency.

[0014] On the other hand, when the Young's modulus of the gel film is less than 230 kgf/mm.sup.2, the gel film is in a soft state. At this time, the support of the gel film itself is insufficient, and it is easy to stick to the embossing wheel and cause the film to rupture, resulting in the inability to produce.

[0015] After the gel film is peeled from the carrier, it is rolled through an embossing wheel with concave and convex shapes and totems at a temperature of 140-200 C. and a pressure of 310 Kgf/cm.sup.2 (S3), so that a surface of the gel film is formed into a concave and convex shape.

[0016] The gel film is baked to 350500 C. to form a polyimide film with a 60 gloss of less than 100 Gus (S4).

[0017] The solvent can be an aprotic polar solvent, such as dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), etc. In the embodiments of the present disclosure, dimethylacetamide is used as a solvent.

[0018] The dehydrating agent can be an aliphatic acid anhydride (such as acetic anhydride and propionic anhydride), an aromatic acid anhydride (such as phenylic anhydride and phthalic anhydride), etc. In the embodiment of the present disclosure, acetic anhydride is used as the dehydrating agent.

[0019] The catalyst can be a heterocyclic tertiary amine (for example, picoline, pyridine, etc.), an aliphatic tertiary amine (for example, triethylamine (TEA), etc.), an aromatic tertiary amine (for example, dimethylaniline, etc.) etc. In the embodiment of the present disclosure, picoline is used as catalyst.

[0020] The following examples describe the present disclosure in detail.

Preparation of Polyimide Precursor Solution

[0021] The diamine monomer and the dianhydride monomer are polymerized in a solvent to form a polyimide precursor solution.

[0022] Preparation of polyimide precursor solution A:

[0023] The diamine monomers, 4.82 g (0.0446 mol) of PDA and 0.99 g (0.0050 mol) of ODA, and the diacid anhydride monomers, 1.08 g (0.0050 mol) of PMDA and 13.11 g (0.0446 mol) of BPDA, are stirred and dissolved in 80.00 g of DMAc solvent to form a polyimide precursor solution A with a solid content of 20 wt %.

[0024] Preparation of polyimide precursor solution B:

[0025] The diamine monomers, 2.93 g (0.0271 mol) of PDA and 4.44 g (0.0222 mol) of ODA, and the diacid anhydride monomers, 5.38 g (0.0246 mol) of PMDA and 7.25 g (0.0246 mol) of BPDA, are stirred and dissolved in 80.00 g of DMAc solvent to form a polyimide precursor solution B with a solid content of 20 wt %.

Example 1

[0026] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution A, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 7.02 ml (2 equivalents) of acetic anhydride and 3.61 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 20 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 140 C., the pressure of the embossing roller was 3 Kgf/cm.sup.2, and the speed of the embossing roller was 1 m/min. After being baked at 350 C. for 1 hour, a polyimide film with a 60 gloss of 89 gloss units (GUs) was formed.

Example 2

[0027] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution A, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 7.02 ml (2 equivalents) of acetic anhydride and 3.61 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 20 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 200 C., the pressure of the embossing roller was 10 Kgf/cm.sup.2, and the speed of the embossing roller was 1 m/min. After being baked at 350 C. for 1 hour, a polyimide film with a 60 gloss of 76 GUs was formed.

Example 3

[0028] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution B, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 6.99 ml (2 equivalents) of acetic anhydride and 3.60 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 20 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 140 C., the pressure of the embossing roller was 3 Kgf/cm.sup.2, and the speed of the embossing roller was 1 m/min. After being baked at 350 C. for 1 hour, a polyimide film with a 60 gloss of 95 GUs was formed.

Example 4

[0029] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution B, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 6.99 ml (2 equivalents) of acetic anhydride and 3.60 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 20 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 200 C., the pressure of the embossing roller was 10 Kgf/cm.sup.2, and the speed of the embossing roller was 4 m/min. After being baked at 350 C. for 1 hour, a polyimide film with a 60 gloss of 82 GUs was formed.

Example 5

[0030] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution A, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 17.55 ml (5 equivalents) of acetic anhydride and 3.61 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 15 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 140 C., the pressure of the embossing roller was 3 Kgf/cm.sup.2, and the speed of the embossing roller was 4 m/min. After being baked at 350 C. for 1 hour, a polyimide film with a 60 gloss of 65 GUs was formed.

Example 6

[0031] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution A, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 17.55 ml (5 equivalents) of acetic anhydride and 3.61 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 15 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 200 C., the pressure of the embossing roller was 10 Kgf/cm.sup.2, and the speed of the embossing roller was 4 m/min. After being baked at 350 C. for 1 hour, a polyimide film with a 60 gloss of 59 GUs was formed.

Example 7

[0032] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution B, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 17.47 ml (5 equivalents) of acetic anhydride and 3.60 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 15 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 140 C., the pressure of the embossing roller was 3 Kgf/cm.sup.2, and the speed of the embossing roller was 4 m/min. After being baked at 350 C. for 1 hour, a polyimide film with a 60 gloss of 72 GUs was formed.

Example 8

[0033] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution B, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 17.47 ml (5 equivalents) of acetic anhydride and 3.60 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 15 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 200 C., the pressure of the embossing roller was 10 Kgf/cm.sup.2, and the speed of the embossing roller was 4 m/min. After being baked at 350 C. for 1 hour, a polyimide film with a 60 gloss of 63 GUs was formed.

Comparative Example 1

[0034] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution A, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 7.02 ml (2 equivalents) of acetic anhydride and 3.61 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 20 minutes to form a polyimide gel film, which was then peeled from the carrier or steel belt. After being baked at 350 C. for 1 hour, a polyimide film with a 60 gloss of 166 GUs was formed.

Comparative Example 2

[0035] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution A, which were then stirred and diluted to obtain a mixture having a solid content of 15 wt %. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 30 minutes to form a polyimide gel film, which was then peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 200 C., the pressure of the embossing roller was 10 Kgf/cm.sup.2, and the speed of the embossing roller was 1 m/min, but the film cannot be formed.

Comparative Example 3

[0036] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution A, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 3.51 ml (1 equivalent) of acetic anhydride and 3.61 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 20 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 200 C., the pressure of the embossing roller was 10 Kgf/cm.sup.2, and the speed of the embossing roller was 1 m/min, but the film cannot be formed.

Comparative Example 4

[0037] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution B, which were then stirred and diluted to obtain a mixture having a solid content of 15 wt %. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 30 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 200 C., the pressure of the embossing roller was 10 Kgf/cm.sup.2, and the speed of the embossing roller was 1 m/min, but the film cannot be formed.

Comparative Example 5

[0038] 25 g of DMAc solvent were added into 75 g of polyimide precursor solution B, which were then stirred and diluted to obtain a solid content of 15 wt %, followed by addition of 3.49 ml (1 equivalent) of acetic anhydride and 3.61 ml (1 equivalent) of methylpyridine to form a mixture. The mixture was coated on a carrier or steel belt, and then baked at 80 C. for 20 minutes to form a polyimide gel film, which was peeled from the carrier or steel belt and then rolled by an embossing roller with a concave and convex surface. The temperature of the embossing roller was 200 C., the pressure of the embossing roller was 10 Kgf/cm.sup.2, and the speed of the embossing roller was 1 m/min, but the film cannot be formed.

[0039] As in the above-mentioned Examples and Comparative Examples, the present disclosure is preferably operated at a temperature of 140-200 C. and a pressure of 3-8 Kgf/cm.sup.2.

60 Gloss Value Test

[0040] In accordance with ASTM D523 specifications, a handheld gloss meter (model: Micro Tri GlossBYK Gardner) was used for testing, and an average value of 3 independent measurement values was taken.

Young's Modulus Test of Gel Films

[0041] After the polyimide gel film was peeled from the carrier or steel belt, the solvent content was 30 wt %. According to the ASTM D882 specification, a universal tensile testing machine (model: Tinius Olsen 10ST) was used for testing, and an average value of 5 independent measurement values was taken.

TABLE-US-00001 TABLE 1 surface Diacid Gel film temperature 60 Acetic Methyl- Diamine anhydride Young's of embossing gloss anhydride pyridine ratio ratio modulus wheel pressure value Item Eq. Eq. PDA ODA PMDA BPDA Kgf/mm.sup.2 C. Kgf/cm.sup.2 GU Example 1 2 1 90 10 10 90 312 140 3 89 Example 2 2 1 90 10 10 90 312 200 10 76 Example 3 2 1 55 45 50 50 235 140 3 95 Example 4 2 1 55 45 50 50 235 200 10 82 Example 5 5 1 90 10 10 90 347 140 3 65 Example 6 5 1 90 10 10 90 347 200 10 59 Example 7 5 1 55 45 50 50 258 140 3 72 Example 8 5 1 55 45 50 50 258 200 10 63 Comparative 2 1 90 10 10 90 166 Example 1 Comparative 90 10 10 90 185 200 10 Example 2 Comparative 1 1 90 10 10 90 205 200 10 Example 3 Comparative 55 45 50 50 178 200 10 Example 4 Comparative 1 1 55 45 50 50 214 200 10 Example 5

[0042] Referring to the above Table 1, the differences between Comparative Examples and Examples are explained as follows.

[0043] First, the difference between Comparative Example 1 and Examples 12 and 56 lies in that Comparative Example 1 is not rolled after film formation. Further, as can be seen from Table 1, the 60 glosses of Examples 12 and 56 are all less than 100 Gus, but the 60 gloss of Comparative Example 1 is 166 GUs, which is not good.

[0044] Secondly, the difference between Comparative Example 2 and Examples 12 and 56 lies in that Comparative Example 2 is reacted under thermal closed loop conditions, no dehydrating agent and catalyst are added, and the Young's modulus of the gel film is less than 230 Kgf/mm.sup.2, such that Comparative Example 2 does not form a film after rolling, so it is not good.

[0045] Furthermore, the difference between Comparative Example 3 and Examples 12 and 56 lies in that Comparative Example 3 reacts under conditions where the equivalent number of the dehydrating agent is insufficient, and the Young's modulus of the gel film is less than 230 Kgf/mm.sup.2, such that Comparative Example 3 does not form a film after rolling, so it is not good.

[0046] Next, the difference between Comparative Example 4 and Examples 34 and 78 lies in that Comparative Example 4 is reacted under thermal closed loop conditions, no dehydrating agent and catalyst are added, and the Young's modulus of the gel film is less than 230 Kgf/mm.sup.2, such that Comparative Example 4 does not form a film after rolling, so it is not good.

[0047] Finally, the difference between Comparative Example 5 and Examples 34and 78 lies in that Comparative Example 5 reacts under conditions where the equivalent number of the dehydrating agent is insufficient, and the Young's modulus of the gel film is less than 230 Kgf/mm.sup.2, such that Comparative Example 5 does not form a film after rolling, so it is not good.

[0048] The content of the above specific embodiments is to illustrate the present invention in detail. However, these embodiments are only for illustration and are not intended to limit the present invention. Those skilled in the art will understand that various changes or modifications made to the present invention without departing from the scope defined in the appended claims are part of the present invention.

[0049] While the present disclosure has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the present disclosure set forth in the claims.