KR100969705B1 - Complex film for manufacturing fpcb and manufacturing method of fpcb using the same - Google Patents

Abstract

The present invention relates to a composite film for manufacturing a flexible printed circuit board (FPCB) and a method for manufacturing a flexible printed circuit board using the same, wherein the composite film comprises HIPP (High Isotactic Poly Propylene) and is spaced apart from each other A layer and a second release layer; It includes a nylon (Polyamide) and is disposed between the first release layer and the second release layer includes a cushion layer provided integrally with the first release layer and the second release layer. Thereby, the releasability can be improved in the hot press process at high temperature and high pressure. In addition, productivity can be improved by reducing the number of manufacturing steps of the flexible printed circuit board.

Flexible Printed Circuit Board, Deformed, HIPP

Description

COMPLEX FILMS FOR MANUFACTURING FPCB AND MANUFACTURING METHOD OF FPCB USING THE SAME

The present invention relates to a composite film for manufacturing a flexible printed circuit board (FPCB) and a method for manufacturing a flexible printed circuit board using the same, and more particularly, to improve the releasability in the hot press process of the flexible printed circuit board manufacturing process, The present invention relates to a flexible film for manufacturing a flexible printed circuit board (FPCB) capable of improving productivity by reducing the productivity, and a method for manufacturing a flexible printed circuit board using the same.

Generally, printed circuit boards (PCBs) are widely used in various electronic products such as TVs, computers, mobile phones, displays, communication networks, and semiconductor modules. As a kind of such PCB, in particular, a flexible printed circuit board (FPCB) having flexible characteristics has been widely used in recent years.

In the manufacturing process of the FPCB, there is a hot press process for thermally compressing an insulating film (Cover-Layer) of a polyimide-based material to the base film. The hot press process is a process of laminating the cover layer on the base film by placing the cover layer on the main body of the FPCB, that is, the base film on which the conductive layer is formed, and pressing the cover layer with the press unit to thermo-compress the cover layer on the base film.

At this time, the release film is interposed between the press part and the cover layer to prevent adhesion between the press part and the cover layer and to smoothly separate the press part and the cover layer after the press work is completed. In general, as a release film, a film coated with silicone to a polyethylene terephthalate (PET) stretched film, which is a kind of cyclic olefin copolymer, is used to impart releasability.

However, a conventional product coated with a silicone coating on PET is used as a release film, which often causes poor release properties in a hot press process at a high temperature and high pressure when the coating is not uniform.

In addition, in the related art, the cover layer is interposed between the press part and the release film so as to adhere well without being lifted up to the base film, and a further release film is laminated between the buffer film and the press part.

However, in the conventional hot press process, since a plurality of films are laminated separately and subjected to a multi-step process to be thermocompressed by a press, there is a problem in that productivity is lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite film for manufacturing a flexible printed circuit board which can improve releasability in a hot press process and reduce the number of working steps in the flexible printed circuit board manufacturing process.

On the other hand, another object of the present invention is to provide a method of manufacturing a flexible printed circuit board that can improve the releasability in the hot press process of the flexible printed circuit board manufacturing process, reduce the number of working steps to improve productivity.

According to the present invention, in the composite film for manufacturing a flexible printed circuit board (FPCB), the first release layer and the second release layer including HIPP (High Isotactic Poly Propylene), and spaced apart from each other; It is achieved by including a nylon (Polyamide), the cushion layer disposed between the first release layer and the second release layer and integrally provided with the first release layer and the second release layer.

Meanwhile, another object of the present invention is to provide a method of manufacturing a flexible printed circuit board (FPCB), comprising: disposing an insulating film on a base film on which a conductive layer is formed; A first release layer and a second release layer including HIPP (High Isotactic Poly Propylene) and spaced apart from each other, and nylon (Polyamide) and disposed between the first release layer and the second release layer, Disposing a composite film on the insulating film, the composite film including a cushioning layer provided integrally with a release layer and a second release layer; Bonding the insulating film to the base film by thermally compressing the composite film and the base film; By separating the composite film from the insulating film.

Melt index of the HIPP (Melt Index) is preferably 0.5 ~ 25g / 10min (230 ℃).

The first release layer and the second release layer each contain 70 wt% or more of the HIPP component; The HIPP isotactic index (Isotactic Index) is preferably 96% or more.

The cushion layer preferably contains at least 50 wt% of a nylon component.

The cushion layer further comprises an acrylate rubber; The total content of the nylon and the acrylate rubber is more preferably 50 wt% or more of the cushion layer.

An adhesive layer may be further provided between the first release layer and the cushion layer and between the second release layer and the cushion layer.

The thickness of the first release layer and the second release layer is in the range of 5㎛ to 500㎛, respectively, and the thickness of the cushion layer may be provided in the range of 20㎛ to 3000㎛, the first release layer and the second release It is preferable that the thickness of a layer is 5 micrometers-30 micrometers, respectively, and the thickness of the said cushion layer is 20 micrometers-250 micrometers.

Preferably, the method further comprises disposing a buffer film on the composite film before the composite film and the base film are mutually thermally compressed.

The step of bonding the insulating film to the base film is preferably thermocompression bonding for less than 150 minutes at a pressure of less than 100kg / cm ² and a temperature of less than 190 ℃.

According to the present invention, a flexible printed circuit board which improves the release property in the hot press process of the flexible printed circuit board manufacturing process, improves the productivity by reducing the number of working steps, and improves the working environment by using a product that is harmless to human body. It is possible to provide a composite film for manufacturing (FPCB) and a method of manufacturing a flexible printed circuit board using the same.

Hereinafter, with reference to the accompanying drawings will be described in detail a composite film 30 for manufacturing a flexible printed circuit board according to the present invention.

The composite film 30 for manufacturing a flexible printed circuit board according to the present invention is used in a hot press process during the manufacturing process of the flexible printed circuit board, as shown in FIG. 1. The composite film 30 for manufacturing a flexible printed circuit board according to the present invention may include a first release layer 31 and a second release layer 35 spaced apart from each other, a first release layer 31, and a second release layer ( The cushion layer 33 is disposed between the first release layer 31 and the second release layer 35. That is, the first release layer 31, the cushion layer 33, and the second release layer 35 are stacked in the upper to lower direction. Here, the first release layer 31, the cushion layer 33, and the second release layer 35 are integrally provided not as a film in which the composite film 30 is stacked in multiple layers, but as one film. It is designed to be handled.

The first release layer 31 and the second release layer 35 include HIPP (High Isotactic Poly Propylene). HIPP is a resin that improves the stereoregularity (Isotacticity) of the polypropylene (PP) by the new catalyst technology, and is a PP that has improved rigidity, heat resistance, and scratch resistance than general PP. The melting temperature of general PP is about 158 ° C, whereas the melting temperature of HIPP is 167 ° C, so the heat resistance of HIPP is superior to that of general PP. The Isotactic Index of HIPP included in the first release layer 31 and the second release layer 35 is 96 or more and 100 or less.

Melt Index (HILT Index) of HIPP is preferably 0.5g / 10min to 25g / 10min (230 ℃). If the melt index is less than 0.5g / 10min (230 ℃), the processing load is high during the extrusion process of the composite film 30 is difficult to work. On the other hand, when the melt index is more than 25g / 10min (230 ℃) is difficult to use because the mechanical properties of the composite film 30 is reduced after extrusion processing.

It is preferable that the first release layer 31 and the second release layer 35 each contain 70 wt% or more of the HIPP component. If the HIPP component is less than 70wt%, the heat resistance is weak so that it melts in the hot press process and poor releasability. Here, the remaining components may be prepared in general PP, PET or PBT.

The composite film 30 having the first release layer 31 and the second release layer 35 is not only excellent in releasability when peeled at room temperature after contact with the insulating film 20 under conditions of high temperature and high pressure in a hot press process. The residue prevents any transition to the insulating film 20.

Meanwhile, although the first release layer 31 and the second release layer 35 have been described and illustrated as having the same composition and thickness, the present invention is not limited thereto and the composition and thickness may be provided differently.

The cushion layer 33 includes nylon (Polyamide). Nylon is at least one selected from the group consisting of nylon 66 (Polyamide 66, melting temperature 243 ℃), nylon 6 (Polyamide 6, melting temperature 215 ℃), nylon 12 (Polyamide 12, melting temperature 195 ℃) and nylon 11 (Polyamide 11) Include. It can be seen that nylon has excellent heat resistance because the melting temperature is higher than that of PVC, which is a component of the conventional buffer film.

It is preferable that the cushion layer 33 contains 50 wt% or more of a nylon component. If the nylon component is less than 50wt%, the heat resistance and the buffer resistance is lowered to prevent the function of the buffer film. The cushion layer 33 may include up to 100 wt% of a nylon component.

Meanwhile, the cushion layer 33 may further include an acrylate rubber. In this case, the total content of nylon and acrylate rubber is preferably 50wt% or more of the cushion layer. The cushion layer 33 may include up to 100 wt% of the total content of nylon and acrylate rubber.

In addition, the cushion layer 33 may further include polybutylene terephthalate (PBT) as a matter of course (see Experiment 1). Also in this case, the cushion layer 33 provides a total content of nylon and polybutylene terephthalate (PBT) in a range of 50 wt% to 100 wt%.

<Table 1> Tensile modulus according to the components of the cushion layer (unit: kgf / mm ² , film thickness: 15㎛, measuring method: ASTM D882)

Here, at the time of film processing, a horizontal direction is called TD and a vertical direction is called MD. On the other hand, the tension modulus of the film (Tensile Modulus) indirectly know the cushion function, the smaller the tensile modulus value, the better the cushion function. As disclosed in Table 1, the cushioning function of the cushion layer 33 can be seen that the best in order of nylon 12, nylon 6, nylon 66. In addition, it can be seen that the cushion function is improved when the cushion layer 33 includes acrylate rubber in nylon 66 as compared with the case in which only nylon 66 is included.

Meanwhile, in the composite film 30 according to the present invention, as shown in FIG. 3, between the first release layer 31 and the cushion layer 33, and between the second release layer 35 and the cushion layer 33. The adhesive layer 37 may further include a tie-layer. The adhesive layer 37 makes it possible to easily adhere the first release layer 31 and the second release layer 35 to the cushion layer 33.

The composite film 30 may be used only as a release film depending on the thickness of the first release layer 31, the second release layer 35, and the cushion layer 33, and may be used as a release film and a buffer film. Sometimes. That is, when the thickness of the composite film 30 is provided thinly, it is used only for the use of a release film, and when the thickness of the composite film 30 is thickly used, it is used as a composite use that simultaneously functions as a release film and a buffer film. do.

Hereinafter, the present invention will be described in detail through experimental results.

Experiment 1 observed the performance when the composite film 30 according to the present invention is used only for the use of the release film in the hot press process of the flexible printed circuit board manufacturing process, Experiment 2 is a composite film (30) ) Was observed to be used for the combination of release film and buffer film in the hot press process of the flexible printed circuit board manufacturing process. 5kg / cm ² hot press process To 100kg / cm ² Thermocompression is performed at a pressure in the range of 110 ° C. to 190 ° C. for a time ranging from 30 minutes to 150 minutes.

The composite film was processed by co-extrusion using a T-DIES extruder, and the ratio (L / D) of the length (L) and the screw diameter (D) of the screw flight portion of the T-die extruder was 20-26. Used. And, the processing temperature of the composite film is 160 ℃ to 260 ℃ based on the cylinder temperature.

HIPP of the first release layer 31 and the second release layer 35 has an isotactic index of 97 or more, and a melt index of 0.5 g / 10 min to 25 g / 10 min (230 ° C.). Phosphorus product was used.

In addition, nylon 66 and nylon 6 of the cushion layer 33 have a viscosity of 3.5 to 3.6, and a product having a density of 1.128 g / cm ³ was used.

Herein, the melt index was measured based on ASTM D1238, the density was measured based on ASTM D1505, and the melting temperature was measured according to ASTM D3418 DSC (Thermal Analyser).

In the following examples, the thicknesses of the first release layer 31 and the second release layer 35 are 12 μm to 13 μm. Note that the size of the printed circuit board and the user's choice are variable.

In the following embodiments, the thickness of the cushion layer 33 is provided to 35 μm to 100 μm, but the thickness of the flexible printed circuit board is not limited to the numerical value, but is within the range of 20 μm to 3000 μm. Note that the thickness of the layer 31 and the second release layer 35 can be varied according to the user's choice.

<Experiment 1: Performance observation when the composite film is used only for the release film>

As disclosed in Table 2 below, in Examples 1 to 3, HIPP having a thickness of 12 μm was provided as the first release layer 31 and the second release layer 35, and the cushion layer 33 had a thickness of 35 μm. Nylon 6, nylon 66, nylon 66 70wt% + PBT 30wt%, respectively. And 150-160 micrometers PVC film was used as a buffer film. In the case of Examples 1 to 3 it is possible to perform the function of a good release film even in a hot press process of high temperature and high pressure.

Meanwhile, in Comparative Examples 1 and 2, the conditions of the first release layer 31 and the second release layer 35 were the same as those of Examples 1 to 3, and the material of the cushion layer 33 was LDPE or PET as in the prior art. Was used. However, in Comparative Example 1, the resin forming the cushion layer 33 melted at high temperature (155 ° C or higher) and high pressure (50 kg / cm ² ) during the hot press process, resulting in poor releasability and a problem in that sliding occurred. In Comparative Example 2, the degree of contamination of the adhesive was poor, and the lifting phenomenon occurred.

In Comparative Examples 3 and 4, the composite film 30 was not multi-layered, and a release film used in the related art was prepared and tested. However, in both cases, the lifting phenomenon occurred, and thus, the function of the release film was not faithfully performed.

TABLE 2

1) Glue contamination measurement standard: The value measured by the adhesive applied to bond the PI film and the copper circuit to the surrounding area through hot press process (good: within 40㎛, usually: 40㎛ ~ 60㎛, Poor: 60 ㎛ or more)

2) Delamination: Circuit defects on the flexible printed circuit board after the work under the working conditions (temperature: 165 ℃, pressure: 50kg / cm ² , time: 80min) of the hot press process result in poor adhesion on the PI substrate. It is a percentage of the number.

On the other hand, sliding (sliding) refers to a phenomenon in which the multilayer flexible circuit boards laminated due to the weakness of the material of the release layer or the buffer pad are melted and melted in the hot press process at high temperature and high pressure to cause defects.

Experiment 2: Observation of Performance when Composite Film is Used in Combination of Release Film and Buffer Film

As disclosed in Table 3 below, in Examples 4 to 6, HIPP having a thickness of 13 μm was provided as the first release layer 31 and the second release layer 35, and 100 μm as the cushion layer 33. Nylon 6, nylon 6 + 10 wt% of acrylate rubber (ACM) and nylon 12 were prepared, respectively. And, no separate buffer film was used. In the case of Examples 4 to 6 it is possible to perform a composite function of a good release film and a buffer film even in a hot press process of high temperature and high pressure.

Here, comparing Examples 4 and 5, it can be seen that the buffering properties are improved when the nylon and the acrylate rubber are used together as compared to using only nylon as the cushion layer 33.

In Comparative Examples 5 to 7, the conditions of the first release layer 31 and the second release layer 35 were the same as those of Examples 4 to 6, and the experiment was performed by changing the material of the cushion layer 33.

However, in Comparative Example 5, the resin forming the cushion layer 33 melts at a high temperature (165 ° C.) or high pressure (50 kg / cm ² ) during the hot press process, resulting in poor releasability, and wrinkles in the surface layer of the flexible printed circuit board. There was a problem that occurred. In Comparative Example 6, the resin forming the cushion layer 33 melts at a high temperature (over 145 ° C.) and a high pressure (50 kg / cm ² ) during the hot press process, resulting in poor releasability, sliding, and a flexible printed circuit board. A problem occurs that wrinkles occur in the surface layer of the. In addition, in Comparative Example 7, there was a problem in that the lifting phenomenon occurred and wrinkles occurred in the surface layer of the flexible printed circuit board.

TABLE 3

In the present embodiments, the composite film 30 was processed in a coextrusion format using a T-DIES extruder, but other composite multilayer films such as coextrusion blown film processing and lamination processing were processed to have natural It can be processed by any processing method in which peeling does not occur.

Hereinafter, a method of manufacturing a flexible printed circuit board (FPCB) using the composite film 30 according to the present invention will be described with reference to FIGS. 2A to 2C.

In the method of manufacturing a flexible printed circuit board (FPCB) according to the present invention, the insulating film 20 is disposed on the base film 10 on which the conductive layer 15 is formed, and the composite film 30 according to the present invention is disposed. A step (see FIG. 2A) disposed on the insulating film 20 and a hot press process of bonding the insulating film 20 to the base film 10 by thermally compressing the composite film 30 and the base film 10 together. Step (see FIG. 2B), and separating the composite film 30 from the insulating film 20 (see FIG. 2C).

As in Experiment 1 described above, when the composite film 30 is provided to function only as a release film, a separate buffer film (not shown) is composited before the composite film 30 and the base film 10 are thermally compressed. The method may further include disposing on the film 30.

As described above, the first release layer 31 and the second release layer 35 including HIPP (High Isotactic Poly Propylene) and spaced apart from each other, and nylon (Polyamide), the first release layer ( 31) and the composite film 30 including the cushion layer 33 disposed between the second release layer 35 and integrally provided with the first release layer 31 and the second release layer 35. In order to withstand the working conditions of high temperature and high pressure, the releasability may be improved, and the buffering property may be improved, so that the insulating film 20 may be adhered to the base film 10 without lifting.

In addition, as in Experiment 2, the thickness of the cushion layer 33 is thicker than in Experiment 1 to provide the composite film 30 to have a composite function of the release film and the buffer film, thereby reducing the number of work steps to reduce productivity. It can improve and solve the environmental problems (chlorine group (Cl ^- generated at high temperature and high pressure)) that can occur by using a buffer film of a separate PVC material. Thus, the working environment can be improved.

1 is a cross-sectional view showing an embodiment of a composite film for manufacturing a flexible printed circuit board according to the present invention;

2a to 2c are views illustrating a manufacturing process of a flexible printed circuit board using a composite film for manufacturing a flexible printed circuit board according to the present invention;

3 is a cross-sectional view showing another embodiment of a composite film for manufacturing a flexible printed circuit board according to the present invention.

Explanation of symbols on the main parts of the drawings

10: base film 20: insulating film

30: composite film 31: the first release layer

33: cushion layer 35: second release layer

37: adhesive layer

Claims (14)

In the composite film for manufacturing a flexible printed circuit board (FPCB), A first release layer and a second release layer including HIPP (High Isotactic Poly Propylene) and spaced apart from each other; A flexible printed circuit board comprising nylon and comprising a cushion layer disposed between the first release layer and the second release layer and integrally provided with the first release layer and the second release layer. Composite film for manufacturing. The method of claim 1, The HIPP has a melt index of 0.5 g / 10 min to 25 g / 10 min (230 ° C.). The method of claim 2, The first release layer and the second release layer each contain 70 wt% or more of the HIPP component; The HIPP isotactic index (Isotactic Index) is a composite film for manufacturing a flexible printed circuit board, characterized in that more than 96%. The method according to any one of claims 1 to 3, The cushion layer is a composite film for manufacturing a flexible printed circuit board, characterized in that it comprises at least 50wt% nylon component. The method according to any one of claims 1 to 3, The cushion layer further comprises an acrylate rubber; The total content of the nylon and the acrylate rubber is a composite film for manufacturing a flexible printed circuit board, characterized in that more than 50wt% of the cushion layer. The method of claim 1, The composite film for manufacturing a flexible printed circuit board further comprises an adhesive layer provided between the first release layer and the cushion layer and between the second release layer and the cushion layer. The method of claim 1, The thickness of the first release layer and the second release layer is 5㎛ to 500㎛, respectively, the thickness of the cushion layer is a composite film for manufacturing a flexible printed circuit board, characterized in that the 20㎛. In the method of manufacturing a flexible printed circuit board (FPCB), Disposing an insulating film on the base film on which the conductive layer is formed; A first release layer and a second release layer including HIPP (High Isotactic Poly Propylene) and spaced apart from each other, and nylon (Polyamide) and disposed between the first release layer and the second release layer, Disposing a composite film on the insulating film, the composite film including a cushioning layer provided integrally with a release layer and a second release layer; Bonding the insulating film to the base film by thermally compressing the composite film and the base film; The method of manufacturing a flexible printed circuit board comprising the step of separating the composite film from the insulating film. The method of claim 8, The first release layer and the second release layer each contain 70 wt% or more of the HIPP component; The HIPP has a stereoregular index (Isotactic Index) of 96% or more, the melt index (Melt Index) of 0.5g / 10min to 25g / 10min (230 ℃) characterized in that the manufacturing method of the flexible printed circuit board. 10. The method of claim 9, The cushion layer is a method of manufacturing a flexible printed circuit board, characterized in that it comprises at least 50wt% nylon component. 10. The method of claim 9, The cushion layer further comprises an acrylate rubber; The total content of the nylon and the acrylate rubber is a manufacturing method of a flexible printed circuit board, characterized in that more than 50wt% of the cushion layer. The method of claim 8, The thickness of the first release layer and the second release layer is 5㎛ to 500㎛ respectively, the thickness of the cushion layer is a manufacturing method of a flexible printed circuit board, characterized in that 20㎛ to 3000㎛. The method of claim 12, And arranging a buffer film on the composite film before thermally compressing the composite film and the base film. The method of claim 8, Bonding the insulating film to the base film is a method of manufacturing a flexible printed circuit board, characterized in that the thermocompression bonding for less than 150 minutes at a pressure of less than 100kg / cm ² and a temperature of less than 190 ℃.

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