TWI656973B - Low-glass doubl polyimide film and method for manufacturing the same - Google Patents

Abstract

A low-gloss double-layer polyimide film and a method for producing the same, comprising: a lower layer polyimide film; and an upper layer polyimide film, wherein the compound component is the same as the lower layer polyimide film Located on one surface of the lower polyimide film, which is mixed with a black pigment and has a plurality of concave portions formed in the film thickness direction and a hole formed in the mold, the concave portion having a depth of 0-5 μm And the concave portion and the hole volume account for 30-70% of the total volume of the mold.

Therefore, a two-layer polyimide film having both high light-shielding property, low glossiness, and no warpage can be obtained, and the production cost thereof is relatively low.

Description

Low-gloss double-layer polyimide film and method for producing same

The present invention relates to a low-gloss double-layer polyimide film and a method for producing the same, and in particular to a two-layer polyimide film having high light-shielding property and no warpage.

Flexible copper clad laminate (FCCL) is widely used in the electronics industry as a circuit board (PCB). In addition to its advantages of lightness, thinness and flexibility, FCCL also has a polyimide film. In addition to the excellent electrical and thermal properties, its low dielectric constant (Dk) makes the electrical signal transfer quickly, good thermal performance, easy to cool components, high glass transition temperature (Tg) , the module can run well at higher temperatures.

However, polyimide films generally have a high surface flatness such that most of the incident light is reflected to produce a high gloss. Also, a high-gloss film surface may cause visual discomfort or eye fatigue when viewed for a long time. In particular, a high-gloss polyimide film having a color, for example, a polyimide film such as black, white, blue, or red, is visually more conspicuous in a large amount of reflected light generated by irradiation on the surface thereof. In addition, low light transmittance and low gloss PI films are commonly used for substrates and coverlays of flexible printed circuit boards, and low light transmittance is used to cover circuit design on the circuit board to prevent The circuits on the board are copied. These flexible boards are widely used in 3C products, optical lens modules, and LCD modules. Low gloss gives the component a more textured and aesthetic appearance.

Studies have shown that the optical interference principle can be used to increase the roughness of the surface of the film by adding a matting agent to the polyimide film to reduce the gloss of the incident light. However, conventionally used matting agents reduce the gloss by utilizing the surface roughness of the protrusions, such as inorganic particles such as cerium oxide, aluminum oxide, calcium carbonate, barium sulfate, and titanium oxide, and organic particles such as polyimine. However, since the inorganic particles have a high dielectric constant, the dielectric constant of the polyimide film may be increased, and the electrical insulation of the polyimide film may be lowered. In addition, the addition of polyimine organic particles as a matting agent has the problem of increasing the material cost. Adding a large amount of matting agent causes the polyimine film itself to be easily brittle, in order to reduce the cost and increase the polyimine. The mechanical strength of the film itself and the reduction of its gloss can be achieved by using a two-layer polyimide film with a large amount of polyamidene particles added to the surface layer, but it is found that the double-layered polyimide film has a warping tension. The problem of unevenness. This suspicion of uneven tension is plagued by the use of the flexible circuit board industry. In view of this, there is a need in the industry for a low-cost matting method for producing a two-layer polyimide film having high light-shielding properties, low gloss, and no warpage.

The present invention is a low-gloss two-layer polyimide film comprising a lower polyimide film; and an upper polyimide film having the same compound composition as the lower polyimide film. a surface of one of the lower polyimide films is mixed with a black pigment and has a plurality of concave portions formed in the film in the thickness direction of the film and a hole formed in the mold, the concave portion having a depth of 0-5 μm . And the concave portion and the hole volume account for 30-70% of the total volume of the mold.

Therefore, a two-layer polyimide film having both high light-shielding property, low glossiness, and no warpage can be obtained, and the production cost thereof is relatively low.

10‧‧‧Lower Polyimine Film

12‧‧‧Upper layer of polyimide film

14‧‧‧Organic materials

16‧‧‧ recessed hole

The first figure is a schematic diagram of the low gloss double-layer polyimine film of the present invention.

The second figure is a schematic diagram of the cost of the low gloss double-layer polyimide film of the present invention.

The third figure is a flow chart of the first manufacturing method of the present invention.

Referring to the first figure, the low-gloss double-layer polyimide film of the present invention comprises a lower layer polyimide film 10 and a compound layer of the same composition as the lower layer polyimide film 10. The polyimine film 12, the upper and lower layers of the polyimide polymer can be obtained by condensation reaction of a diamine compound and a dianhydride compound. In the examples or comparative examples, the diamine is selected from the group consisting of 4,4'-oxydiamine (4,4'-ODA) and phenylenediamine (p). -PDA), 1,3-bis(4'-aminophenoxy)(1,3-bis(4-aminophenoxy)benzene(TPER), 1,4-bis(4-aminophenoxy) Benzene (1,4-bis(4-aminophenoxy)benzene (TPEQ)), 4,4'-diamino-2,2'-dimethyl-1,1'-linked (2,2'-dimethyl[ 1,1'-biphenyl]-4,4'-diamine(m-TB-HG)), 1,3-bis(3-aminophenoxy)benzene (1,3'-Bis(3-aminophenoxy) Benzene (APBN)), 3,5-DiaminoNoben zotrifluoride (DABTF), 2,2'-bis(trifluoromethyl)benzidine (2,2'-Bis ( Trifluoromethyl)benzidine(TFMB)), 2,2'-bis[4-(4-aminophenoxyphenyl)]propane (2,2'-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) )), 6-amino-2-(4-aminophenyl)benzoxazole (6PBOA), 5-amino-2-(4) -Amino-2-(4-aminopenyl)benzoxazole (5PBOA), etc., may be used singly or in combination.

In the bilayered polyimide layer, in the examples or comparative examples, the dianhydride is selected from the group consisting of pyromellitic dianhydride (PMDA), 3,3', 4,4'-biphenyl. Tetracarboxylic acid Diacid anhydride (3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA)), 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (2,2- Bis[4-(3,4dicarboxyphenoxy)phenyl]propane dianhydride(BPADA)), 4,4'-Bis-(3,4-Dicarboxyphenyl)hexafluoropropane dianhydride(2,2'-Bis-(3,4-Dicarboxyphenyl)hexafluoropropane dianhydride 6FDA)), 4,4-Oxydiphthalic anhydride (ODPA), Benzophenonetetracarboxylic dianhydride (BTDA), 3,3',4,4'-bicyclic Hexanetetracarboxylic acid dianhydride (3,3',4,4'-dicyclohexyltetracarboxylic acid dianhydride (HBPDA), etc., may be used singly or in combination.

In order that the appearance of the bilayered polyimide film is not curled, the diamine and dianhydride compounds selected for the upper and lower polyimine layers 10, 12 are identical, for example, the first polyimide layer The high molecular polymer is formed by condensation reaction of a diamine compound (4,4'-ODA) and a dianhydride compound (PMDA); the polymer of the second polyimine layer must also be selected from a diamine compound (4) , 4'-ODA) and a dianhydride compound (PMDA) are formed by condensation reaction.

The upper polyimine film 12 is doped with a thermally decomposable organic material 14, and in the present embodiment, the thermally decomposable organic material 14 is a crosslinked methyl methacrylate particle (crosslinked PMMA) and Polystyrene particles or the like may be used singly or in combination, wherein the polyimine film 12 has a density of 1.49 g/cm 3 and the crosslinked methyl methacrylate particles (crosslinked PMMA) have a density of 1.18 g/cm 3 . The density of the polystyrene particles is g/cm3.

If the average particle diameter of the thermally decomposable organic material particles 14 is about 1 to 2 μm , the thermally decomposable organic material particles 14 may occupy about 40 to 60% by weight of the upper polyimine layer 12; Yttrium layer thickness The average particle diameter of the thermally decomposable organic material particles is, for example, the amount of the thermally decomposable organic material particles added is 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt% or a value between any two of the foregoing; And the thickness is 1 μ m, 1.5 μ m, 2 μ m or a value between any two of the foregoing. If the average particle diameter of the thermally decomposable organic material particles is about 4 to 5 μm , the thermally decomposable organic material particles may comprise about 35 to 65 wt% of the upper polythenimine layer; and the upper layer of polyfluorene Amine layer thickness The average particle diameter of the thermally decomposable organic material particles is, for example, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt% or a value between any two of the foregoing; and a thickness of 1 μ m, 1.5 μ m, 2 μ m, 3 μ m, 4 μ m, 4.5 μm , 5 μ m or a value between any two of the foregoing.

The black pigment is blended in the double-layered polyimide film 10 and 12, and the type of the black pigment is not particularly limited, and may be carbon microparticles, chromium or titanium black pigment. Specifically, the black pigment may be carbon black, titanium black, bone black, cyanine black, acetylene black, lamp black, graphite, iron black, nigrosine or cyanine black, but not This is limited. For the consideration of the light blocking rate, carbon black or titanium black can be used. In addition, the above black pigment may also be used in combination; and if the black pigment blended accounts for 4.5% by weight of the layer, the thickness of the lower polyimide film 10 is required. 8 μm , for example, a thickness of 8 μm , 9 μm , 10 μm , 20 μm , 40 μm , 80 μm , 100 μm or a value between any two of the foregoing.

Referring to the third drawing, a flow chart of an embodiment of the present invention provides a layer of polyimide film 10 (step S1), which provides a layer of the same compound as the lower layer of polyimide film 10 The body solution (step S2) is subjected to thermal decomposition of the organic material material 14 on the surface of one of the lower polyimide film 10 (step S3), and the upper layer polyimide precursor solution hardening operation (step S4) is performed to make the lower layer polymerize. An upper polyimide film 12 (S5) is formed on the surface of the imine film 10. As shown in the second figure, since the organic particles 14 on the surface of the upper polyimide film 12 have been thermally decomposed, the upper layer of polyimide The 12 skin layer can be formed to have a plurality of recessed holes 16 as shown in Table 2.

When the plurality of concave holes 16 are formed in the surface layer of the upper polyimide film 12 by the above-described production method, a low-cost matting method can be used to prepare a double layer having high light-shielding property, low gloss, and no warpage. Polyimine film. The 60 degree angle gloss of the upper layer of the polyimide film 12 is less than about 20, such as 19.7, 18.2, 15.4, 10.3, 1.2, etc., or a value between any two of the foregoing. Its light transmittance (TT) is less than about 0.2, such as 0.17, 0.14, 0.09, 0.02, 0.01, etc., or a value between any two of the foregoing.

60 degree angle gloss measurement (gloss)

The 60 degree angle gloss measurement was measured with a hand-held gloss meter (Model: Micro Tri Gloss-BYK Gardner).

Light transmittance measurement (TT)

The penetration of the polyimide film was measured by Nippon Denshoku NDH 2000 Haze Meter (%)

Example

Preparation of carbon black slurry

500 g of carbon black (Regal-R400, purchased from CABOT Co., Ltd.) was mixed with 4000 g of DMAc for 15 minutes, and then ground by a grinder.

Preparation of polyaminic acid solution

52.63 grams of 4,4'-ODA and 440 grams of DMAc were placed in a three-necked flask. After stirring at 30 ° C until complete dissolution, 56.51 g of PMDA (20 wt% of the total weight of the 4,4'-ODA and PMDA monomers) was added. Subsequently, the stirring was continued and the reaction was continued at 25 ° C for 20 hours to obtain a polyaminic acid solution having a rotational viscosity of 140,000 cps at 25 ° C.

Preparation of black polyaminic acid solution

42.39 g of carbon black slurry was prepared by copolymerizing 500 g of polyamic acid solution (20 wt%, 4,4'-ODA, para-phenylenediamine (p-PDA) and PMDA, The viscosity was about 140,000 cps) and 129 g of DMAc solvent was stirred and mixed to obtain a black polyaminic acid solution (carbon black powder having a total weight of 4.5 wt%) of 15 wt% and a weight of about 671.39 g.

<Example 1>

Take 50 grams of the obtained black polyaminic acid solution, stir evenly, and then add appropriate amount of acetic anhydride and methylpyridine catalyst (the ratio of addition is polyacetic acid solution: acetic anhydride: methylpyridine molar ratio is about 1 : 2:1), after defoaming, a doctor blade having a coating gap of 600 μm was applied to the glass plate, and heated in an oven at 80 ° C for about 30 minutes to remove most of the solvent. Next, the above-mentioned glass plate coated with the black polyaminic acid solution was placed in an oven at 170 ° C to 350 ° C and heated for about 4 hours to allow the polyamic acid solution to be baked to form a film. The resulting lower polyimide film thickness was 25 μm . Next, the same operation method as the lower polyimide film was obtained, but 5 g of the crosslinked PMMA powder was added to 50 g of the black polyaminic acid solution (the average particle size of the crosslinked PMMA powder was 1 to 2 μm , And the total weight of the monomer is 40% by weight), a doctor blade having a coating gap of 30 μm is selected, and the obtained black polyaminic acid solution containing the crosslinked PMMA powder is coated on the obtained lower polyimide film. The upper layer of the polyimide film was obtained to have a thickness of 1 μm .

<Example 2>

The same as Example 1, except that the amount of the crosslinked PMMA powder added in the upper polyimide film was changed to 7.5 g (the crosslinked PMMA powder was 50% by weight based on the total weight of the monomers).

<Example 3>

Same as Example 1, except that the amount of the crosslinked PMMA powder added in the upper polyimide film was changed to 11.25 g (the crosslinked PMMA powder was 60% by weight based on the total weight of the monomers).

<Example 4>

Same as in Example 1, except that the average particle diameter of the crosslinked PMMA powder in the upper polyimine film was changed to 4 to 5 μm, and the addition amount was changed to 4 g (crosslinked PMMA powder accounted for 60 wt% of the total monomer weight) %).

<Example 5>

Same as in Example 1, except that the average particle diameter of the crosslinked PMMA powder in the upper polyimine film was changed to 4 to 5 μm, and the addition amount was changed to 7.5 g (crosslinked PMMA powder accounted for 50 wt% of the total monomer weight) %).

<Example 6>

Same as in Example 1, except that the average particle diameter of the crosslinked PMMA powder in the upper polyimine film was changed to 4 to 5 μm, and the addition amount was changed to 13.93 g (the crosslinked PMMA powder accounted for 65 wt% of the total monomer weight) %).

<Example 7>

The same as in Example 2, except that the gap of the coating blade of the upper polyimide film was changed to a 40 μm doctor blade.

<Example 8>

The same as in Example 5, except that the gap of the coating blade of the upper polyimide film was changed to a doctor blade of 80 μm.

<Example 9>

The same as in Example 2, except that the gap of the coating blade of the lower polyimide film was changed to a doctor blade of 120 μm.

<Example 10>

The same as in Example 2, except that the gap of the coating blade for the lower polyimide film was changed to a doctor blade of 1500 μm.

<Example 11>

The same as in Example 5, except that the gap of the coating blade of the first polyimide film was changed to a doctor blade of 120 μm.

<Example 12>

The same as in Example 5, except that the gap of the coating blade of the first polyimide film was changed to a doctor blade of 1500 μm.

Comparative example

Preparation of polyimine powder

14.35 g of 4,4'-diaminodiphenyl ether (4,4'-oxydianiline, 4,4'-ODA), 15.65 g of pyromellitic dianhydride (PMDA) and 570 g of dimethyl b The dimethyl acetamide (DMAc) was placed in a three-necked flask (5 wt% of the total weight of the 4,4'-ODA and PMDA monomers), and after stirring until completely dissolved, 3.35 g of 3-methylpyridine was added. Subsequently, the mixture was stirred and heated at 165 ° C for 18 hours to obtain a polyamidene precipitate. Subsequently, the polyimine precipitates were washed with water and ethanol, and the precipitate was collected by vacuum filtration. Finally, the polyimine precipitates were placed in an oven at 160 ° C for 1 hour to obtain a polystyrene powder (PI powder) having an average particle diameter of 1 to 2 μm and 26.7 g. By repeating the above method, if the above solvent DMAc is changed to 470 g, that is, the total weight percentage of 4,4'-ODA and PMDA monomers is 6 wt%, a PI powder having an average particle diameter of 4 to 5 μm and 32.3 g can be obtained. .

<Comparative Example 1>

Same as Example 1, but adding the crosslinked PMMA powder in the upper polyimine film The addition amount was changed to 4 g (the crosslinked PMMA powder accounted for 35 wt% of the total monomer weight).

<Comparative Example 2>

The same as Example 1, except that the amount of the crosslinked PMMA powder added in the upper polyimide film was changed to 13.93 g (the crosslinked PMMA powder accounted for 65 wt% of the total monomer weight).

<Comparative Example 3>

In the same manner as in Example 4, the amount of the crosslinked PMMA powder added in the upper polyimide film was changed to 3.21 g (the crosslinked PMMA powder was 30% by weight based on the total weight of the monomers).

<Comparative Example 4>

In the same manner as in Example 4, the amount of the crosslinked PMMA powder added in the upper polyimide film was changed to 17.5 g (the crosslinked PMMA powder was 70% by weight based on the total weight of the monomers).

<Comparative Example 5>

The same as in Example 2, except that the gap of the coating blade of the upper polyimide film was changed to a blade of 45 μm.

<Comparative Example 6>

The same as in Example 5, except that the gap of the coating blade of the upper polyimide film was changed to a blade of 90 μm.

<Comparative Example 7>

The same as in Example 2, except that the gap of the coating blade of the lower polyimide film was changed to a blade of 95 μm.

<Comparative Example 8>

The same as in Example 5, except that the gap of the coating blade of the lower polyimide film was changed to a blade of 95 μm.

<Comparative Example 9>

In the same manner as in Example 2, the crosslinked PMMA powder of the upper polyimine film was changed to a PI powder having an average particle diameter of 1 to 2 μm.

<Comparative Example 10>

In the same manner as in Example 5, the crosslinked PMMA powder of the upper polyimine film was changed to a PI powder having an average particle diameter of 4 to 5 μm.

The test results are as follows: Table 1

Claims (13)

A gloss double-layer polyimide film comprising: a lower polyimide film; and an upper polyimide film having the same compound composition as the lower polyimide film in the lower layer a surface of one of the polyimide films, which is mixed with a black pigment and has a plurality of concave portions formed in the film in the thickness direction of the film and a hole formed in the mold, the concave portion having a depth of 0-5 μm , and The volume of the recess and the hole accounts for 30-70% of the total volume of the mold. The polyimine film according to claim 1, wherein the lower polyimine film consists of a diamine and a dianhydride. The polyimine film according to claim 1, wherein the lower polyimide film further comprises a black pigment. The polyimine film according to claim 1 or 3, wherein the black pigment is carbon black, titanium black, bone char or a mixture thereof. The polyimine film according to claim 3, wherein the black pigment accounts for 4.5% of the total amount of the film, and the film has a thickness of 8 μm . The polyimine film according to claim 1, wherein the upper polyimide film has a thickness of 1-2 μm , and the concave portion and the pore volume account for 40-60% of the total volume of the mold. A method for producing a low-gloss double-layer polyimide film, comprising the steps of: providing a solution of a lower polyimine precursor composed of a diamine and a dianhydride compound; providing a layer with the lower layer The upper layer of the same compound of the amine precursor solution is a polyimine precursor solution, the upper layer of the polyimide precursor solution contains a thermally decomposable organic material, and the volatilization temperature of the organic material is lower than the temperature of the polyimidization So that the thermally decomposable organic material has volatilized before the upper and lower layers of the polyimide film, so that a plurality of concave portions are formed on the surface of the upper polyimide film, and the depth of the concave portion is 0-5 μm . And the concave portion and the hole volume account for 30-70% of the total volume of the mold. The method of claim 7, wherein the lower polyimide film comprises a black pigment which is carbon black, titanium black, bone char or a mixture thereof. The method of claim 7, wherein the upper polyimide film comprises a black pigment, and the black pigment is carbon black, titanium black, bone char or a mixture thereof. The method of claim 7, wherein the lower polyimide film comprises a black pigment, the black pigment accounting for 4.5% of the total amount of the film, and the film having a thickness of 8 μm . The method of claim 7, wherein the upper layer of the polyimide film has a thickness of 1-2 μm , and the recess and the pore volume account for 40-60% of the total volume of the mold. The method of claim 7, wherein the organic material is crosslinked methyl methacrylate particles (PMMA) powder or polystyrene particles. The method of claim 7, wherein the upper layer of the polyimide precursor solution is coated on the lower layer of the polyimide film, and the organic material which is thermally decomposable is volatilized by heating to become a double layer. Imine film.