JP2701924B2 - Release film made of poly-4-methyl-1-pentene having both surfaces roughened and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to poly-4-methyl-1-pentene (hereinafter referred to as PM
P) and a method for producing the same. More particularly, the present invention relates to a PMP obtained by uniaxially stretching a melt-extruded PMP film and performing roughening on both surfaces of the film by embossing rolls. And a method for producing the same.

(Prior art) In recent years, as the degree of integration of ICs has increased with the rapid progress of electronic equipment, printed wiring boards have been diversified to meet the demands for higher precision, higher density, and higher reliability. It is well known that this has been done. As this printed wiring board, there are a single-sided printed wiring board, a double-sided printed wiring board, a multilayer printed wiring board, and a flexible printed wiring board, but among them, an insulating layer is integrated in the middle of three or more conductors, and integrated. The application field of the multilayer printed wiring board has been widened in that any conductor layers can be connected to each other and the leads of the electronic component to be mounted can be connected to any conductor layer.

This multilayer printed wiring board has a pair of one side or both sides sealed with an outer layer board, and alternately stacked on the inside thereof through one or more inner layer circuit boards or a prepreg such as epoxy resin or unsaturated polyester resin, While holding these with a jig, it is manufactured by curing and integrating the prepreg with a press hot plate via a cushion material, but when manufacturing this multilayer printed wiring board using an outer layer board, The adhesive strength between the outer layer plate and the adhesive prepreg becomes poor, and there are many cases where delamination occurs, in order to enhance the adhesive force, in the manufacturing process of the outer layer plate,
The resin surface is roughened by pressing a steel press pan with a roughened surface on the resin surface, or by pressing a film or sheet with a roughened surface in contact with the resin surface, increasing the bonding surface area. A way to make it happen.

The present inventors have obtained a finding that a film or sheet having a roughened surface made of PMP can be suitably used as a sheet for forming a rough surface on the resin surface of the outer layer plate, and has already applied for a patent ( JP-A-62-32031).

The surface-roughened film or sheet made of PMP has excellent heat resistance and rigidity, and is further pressed by a hot press to form a rough surface, and after forming a rough surface on the resin surface of the laminate. Since it has excellent releasability from the resin surface, it is suitably used as a release film for forming a rough surface of a multilayer board at the time of manufacturing the multilayer printed wiring board.

While the present inventors have continued the research for obtaining a release film with higher rigidity while repeating the above-mentioned invention, it has been conventionally difficult to perform embossing after uniaxial stretching. After uniaxially stretching the PMP film that had been obtained, by performing ensing under a specific temperature and pressure, it was found that a suitable rough surface could be formed on the surface of the film, and the present invention was completed. Reached.

(Object of the Invention) Accordingly, an object of the present invention is to provide a PMP release film which is more rigid than conventionally known PMP release films, and a method for producing the same.

(Means for Solving the Problems) According to the present invention, after a melt-extruded PMP film is uniaxially stretched, the film is heated at a high temperature of 100 to 220 ° C. and 50 to 200 kg / mm ² under high pressure. By embossing both sides, a release film with excellent rigidity and hence a strong stiffness can be obtained. This release film has a high heat resistance in recent years to increase the wiring speed and improve reliability. Even when heated and pressed by high temperature during the production of a multilayer printed wiring board, which tends to be required, sufficient shape retention can be maintained, and because of this stiffness, the prepreg surface The release can be easily performed, and a product having a stable shape can be produced due to excellent transferability without wrinkling of the film at all.

(Description of Preferred Embodiments) PMP in the present invention is a homopolymer of 4-methyl-1-pentene, or 4-methyl-1-pentene and another α-olefin, for example, ethylene, propylene, 1-olefin.
Butene, 1-hexene, 1-octene, 1-decene, 1
-C2-C20 such as tetradecene, 1-octadecene, etc.
Is a copolymer with α-olefin, usually 4-methyl-1
-Refers to a polymer mainly composed of 4-methyl-1-pentene containing 85 mol% or more of pentene. Melt flow rate of poly-4-methyl-1-pentene (load: 5kg, temperature: 260 ° C)
Is preferably in the range of 0.5 to 250 g / 10 min.
A melt flow rate of less than 0.5 / 10 min has a high melting point and poor moldability, and a melt flow rate of more than 250 g / 10 min has low melt viscosity and poor moldability and low mechanical strength.

In addition, PMP impairs the purpose of the present invention with various additives known to be used in polyolefins such as heat stabilizers, weather stabilizers, rust inhibitors, copper damage stabilizers, and antistatic agents. It can be blended in a range that is not
A small amount of silicone oil can be blended to further improve the releasability of the PMP film.

FIG. 1 shows an example of a process in which a melt-extruded PMP film is subjected to embossing under a high temperature and a high pressure after uniaxial stretching, and FIG. 1 shows a PMP melt-extruded from an extruder 1 through a T-die.
The film is first cooled at about 60 ° C. by the cooling roll 2 and then heated to about 150 ° C.
The film is heated at 3 'and subsequently uniaxially stretched by stretching rolls 4, 4' at a stretching ratio of 2.5 to 6 times, preferably 4 to 5 times. The rigidity of the PMP film uniaxially stretched at such a magnification is improved, and the PMP film cannot be subjected to a surface roughening treatment using an emboss roll as it is. Therefore, in the present invention, the PMP film after the uniaxial stretching is subjected to 150 to 150
After heating to 220 ° C., preferably 170 to 190 ° C., it is fed into the embossing roll 6. The high-temperature heating by the second heating roll 5 preferably uses two or three heating rolls in order to sufficiently raise the temperature of the PMP film. The surface roughening treatment by the embossing roll 6 can be performed on both surfaces simultaneously. However, after performing one surface, the surface is heated again by the third heating roll 7 at a high temperature, and then the surface roughening treatment on the other surface is performed. The preferred surface roughening treatment can be achieved. At this time, the pressure between the embossing roll 6 and the pressure roll 8 is
It is carried out at 50 to 200 kg / mm ² , preferably at 75 to 100 kg / mm ² . When the heating and pressing conditions of the PMP film after the uniaxial stretching are below the above-mentioned ranges, the PMP film cannot be sufficiently subjected to the surface roughening treatment by the embossing roll.

The PMP film is usually obtained by melt extrusion in a thickness of 20 μ or more, but the release film in the present invention includes a film generally recognized as a sheet such as 20 to 300 μ, particularly embossed. From the viewpoint of easy processing and economy, 30 to 50 μm is preferably used.

The surface of the release film in the present invention has an average roughness of 0.
It is preferably 5 to 10 μm. When the average roughness is 0.5μ or less, it is close to a smooth state, which is insufficient for the purpose of increasing the surface area, and does not significantly improve the adhesive strength between the cured resin and the prepreg. On the other hand, if it exceeds 10 μm, there is a tendency that peeling of the cured resin from the release film does not proceed smoothly.

As the emboss roll, a roll obtained by roughening the surface of a metal roll is used because the rigidity of the PMP film is large.

A method for manufacturing a multilayer printed wiring board using the PMP release film thus obtained will be described.

In FIGS. 2 to 4 showing the manufacturing process of the multilayer printed wiring board, FIG. 2 shows an arrangement of each layer before pressing at the time of manufacturing the outer layer board.

A copper foil 14 'is placed on the press heating 11' via a cushion material 12 'and a jig 13', and the copper foil 14 'is integrated with the copper foil 14 by heat curing to adhere to the inner layer circuit board. Prepreg 15 'is placed. On the pre-breg 15 ′, the pre-breg 15 and the copper foil 14 are placed via the release sheet 16, in a manner opposite to the above-mentioned layer configuration, and the jig 15 and the cushion material 16 are used to press the hot plate. By heating and pressing of 11, 11 ', two outer plates in which the copper foil and the pre-breg are integrated are formed. FIG. 3 shows a state in which the formed outer layer plate and the release film have been peeled off.

FIG. 4 shows a structure when a multilayer printed wiring board is manufactured using the outer plates 17, 17 'obtained by roughening the surface of the cured resin thus obtained, and the outer layer is the same as the cured resin. It is integrated by heating and pressing through a synthetic resin pre-breg 15 ″. FIG. 4 shows this state, and the outer layer plate is shown.
By roughening the surface of the cured resin of 17, 17 ', it is possible to obtain a multilayer printed wiring board having excellent adhesive strength with Prebleg 15 ".

Heating when forming the outer layer board and the multilayer printed wiring board,
Both are usually performed at about 130 to 180 ° C, and the pressure is 5 kg / mm
After heating pre 30 to 60 minutes at ² G, but performs a pressing 30kg / mm 30 to 60 minutes at ² G, the release film of the present invention is up to 180 ° C., and 50 kg / mm ² approximately G It can withstand heat and pressure.

As described above, the release film of the present invention is roughened on both the front and back surfaces, so that the release film contact surface of the pre-blegg is roughened upon curing, and the outer layer plate is formed with an increased surface area. Is done.

The biggest feature of the release film of the present invention is that it is uniaxially stretched.
The point is that the PMP film has been roughened. The use of PMP uniaxially stretched as a release film, the stiffness of the film becomes what was remarkably improved, the effect is not yet the rigidity of the stretched PMP film at 250 kg / mm ² approximately at break strength in the machine direction On the other hand, the rigidity of the uniaxially stretched PMP film is apparent from the fact that it reaches 660 to 740 kg / mm ² .

The PMP film of the present invention has such a very high rigidity that even during severe heating and pressurization during press molding, the film surface does not wrinkle and the rough surface formed on the film surface does not disappear. In addition, because of its excellent transferability, the production of multilayer printed wiring boards obtained by heating and pressurizing at high temperatures, for which high heat resistance has recently been required to increase wiring speed and improve reliability, has been required. It has an excellent feature that it can be performed stably.

(Examples) Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

The film properties in Table 1 were measured by the following methods.

1.YS.TS.EL. ‥‥ ASTM D 638 2.Gloss ‥‥ JIS Z 8741 3.Surface roughness ‥‥ DIN 4768 4.Heating collection rate を Predetermined film sample with a mark line with a gap of about 10cm After leaving in a temperature atmosphere for 30 minutes, take out, 23 ℃, 50%
The dimensions were measured after being left for 30 minutes in an atmosphere of RH, and the shrinkage was calculated by the following formula. l ₀ : Length between marked lines l ₁ : Length between marked lines after heating Example 1. Main component is 4-methyl-1-pentene obtained by copolymerizing 6% by weight of n-octadecene- Melt flow of pelletized crystalline copolymer measured at 260 ° C and 5 kg load
Using a polymer having a rate of 25 as a raw material, a polymethylpentene polymer film was extruded with a 90 mmφ-screw extruder having a cast die. The temperature condition of the extruder is
A film of about 0.20 mm was extruded at a cylinder temperature of 300 ° C and a die temperature of 280 ° C. The roll speed at this time is 3.5m / min
Met. The extruded film is cooled and solidified by a chill roll at 85 ° C, and then preheated by two preheating rolls at 155 ° C and 190 ° C. The preheated film has a take-off speed of 14m /
The film was stretched four times by a min stretching roll. Next, the stretched film was preheated by a preheating roll at 150 ° C., and then embossed on one side by a metal embossing roll having a pressing pressure of 100 kg / mm ² . The temperature of the embossing roll used at this time was 150 ° C., and the one subjected to liquid honing was used. Next, the other side was embossed with another embossing roll. The roll temperature and the pressing pressure were the same as those used for embossing the first surface. Using the mat film thus formed, a 30 .mu.m copper foil and a 0.8 mm glass fiber-filled epoxy prepreg (resin content = 52 wt%) were press-formed in the configuration shown in FIG.

Press molding, at 130 ° C. in the first pressing pressure 15 kg / mm ² 45
After heating for 1 minute and then at 180 ° C. for 1 hour under a pressure of 40 kg / mm ² , the epoxy prepreg was completely carried. This molded product is cooled to room temperature, the molded product is peeled off,
The peelability was evaluated.

 As a result, the releasability after pressing was good.

Example 2 Evaluation was made in the same manner as in Example 1 except that a crystalline 4-methyl-1-pentene copolymer containing 5% by weight of n-dodecene-1 was used. As a result, the releasability of the film was good. Met.

Comparative Example 1. The raw material of Example 1 was used to prepare a 90 having a cast die.
A polymethylpentene polymer film was extruded with an mmφ-screw extruder. The temperature conditions of the extruder were such that a 50 μm T-die film was formed at a cylinder temperature of 300 ° C. and a die temperature of 280 ° C. The extruded film was cooled and solidified by a chill roll at 85 ° C., and then this film was preheated by a preheating roll at 150 ° C., and then embossed on one side by an embossing roll at a pressing pressure of 100 kg / mm ² . . The temperature of the embossing roll used at this time was 150 ° C., and the one subjected to liquid honing was used. Next, another emboss
The opposite side was embossed with a roll. The roll temperature and the pressing pressure were the same as those used for embossing the first surface. Using the thus formed mat film, press molding was performed in the same manner as in Example 1, and the releasability was evaluated.

As a result, the film was torn when peeled from the epoxy resin, and the releasability was poor.

Table 1 shows the physical properties of the films obtained in Examples 1 and 2 and Comparative Example 1.

[Brief description of the drawings]

The first is a perspective view showing an example of the apparatus for producing a roughened film of the present invention, FIGS. 2 and 3 are cross-sectional views showing steps of producing an outer layer board of a multilayer printed wiring board, and FIG. It is sectional drawing which shows an example of the process of manufacturing a multilayer printed wiring board using the said outer layer board. 1. Extruder, 2. Cooling roll, 3, 3 '... First heating roll, 4, 4' ... Stretching roll, 5 ... Second heating roll, 6 ... Embossing roll, 7 ... 3 heating rolls, 8
… Pressurized roll, 11,11 ′… Pressed heating plate, 12,12 ′…
... Cushion material, 13,13 '... Jig, 14,14' ... Copper foil,
15,15 '…… prepreg, 15 ″… adhesive prepreg, 1
6 ... Roughened release film, 17,17 '... Outer plate, 18 ... Inner plate with copper circuit.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29K 105: 06 B29L 31:34

Claims (5)

(57) [Claims] 1. A release film made of poly-4-methyl-1-pentene, wherein roughened surfaces are formed on both sides of a uniaxially stretched poly-4-methyl-1-pentene film by embossing. 2. The release film according to claim 1, wherein the average roughness of the film surface is 0.5 to 10 μm. 3. Poly-4, characterized in that a poly-4-methyl-1-pentene film melt-extruded from an extruder is uniaxially stretched, and both surfaces of the film are roughened by embossing rolls under high temperature and high pressure. A method for producing a release film made of methyl-1-pentene. 4. The method according to claim 1, wherein the embossing is performed at 100 to 220.degree.
200 kg / mm ² hot, claim (3) are intended to be carried out under high pressure process according. 5. The method according to claim 3, wherein the uniaxial stretching is performed at a stretching ratio of 2.5 to 6 times.