JPH0361011A - Mold release film and manufacture thereof - Google Patents

Abstract

PURPOSE:To stably manufacture a multi-layer printed wiring board for which high heat resistance is required, by a method wherein a uniaxially stretched 3MB film to which surface-roughening treatment is performed is used as a mold release film. CONSTITUTION:After 3MB film raw fabric, which is melted and extruded through a T die from an extruding machine 1 is cooled down to 60 deg.C with a roll 2, the same is reheated by the first heating rolls 3, 3 heated to 180 deg.C and uniaxially stretched at 1-8 magnifications by passing through stretching rolls 4, 4'. The 3MB film after biaxial stretching is reheated at 100-290 deg.C by the second heating roll 5 and then sent into an embossing roll 6. In this instance, pressure between the embossing roll 6 and a pressing roll 8 is set up ordinarily so as to fall within a range of 20-400kg/mm<2>. The film melted, extruded and made of 3MB (3-methyl-1-butane) becomes a mold release film which is superior in rigidity and stiff by performing embossing processing after uniaxial stretching and the film endures sufficiently harsh conditions at the time of manufacturing of a multi-layer printed wiring board.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to poly-3-methyl-1-butene (hereinafter referred to as 3MB
) and a method for producing the same.

More specifically, the present invention relates to a release film made from 3MB in which a melt-extruded film made from 3MB is uniaxially stretched and then roughened on both sides of the film using an embossing roll, and a method for producing the same.

BACKGROUND OF THE INVENTION In recent years, with the rapid advancement of electronic devices, integrated circuits (ICs) with increasingly higher degrees of integration are being developed. It is well known that various types of printed wiring boards have been used to meet the demands for higher precision, higher density, and higher reliability of integrated circuits. As this printed wiring board,
There are single-sided printed wiring boards, double-sided printed wiring boards, multilayer printed wiring boards, and flexible printed wiring boards. Among them, multilayer printed wiring boards have a structure in which three or more layers of conductors are laminated with an insulating layer interposed between them. It has the advantage that it is possible to connect between any conductor layers, and also to connect the leads of other mounted electronic components to any conductor layer. Taking advantage of these advantages, multilayer printing The application fields of wiring boards are expanding.

This multilayer printed wiring board is produced by, for example, alternately laminating two or more internal circuit boards through prepregs such as epoxy resin or unsaturated polyester resin, and then using a jig to pass the laminate through a cushion fence. It is manufactured by clamping the prepreg together, curing the prepreg with a press hot plate, and then sealing one or both sides of this laminate with an outer layer plate.

In such a method, the adhesive strength between the multilayer printed wiring board and the adhesive prepreg is likely to be poor, and in this case, delamination often occurs.

Therefore, in order to strengthen these adhesive forces, in the manufacturing process of the outer layer board, a steel press pan with a roughened surface is applied to the resin surface, or a film or sheet with a roughened surface is applied to the resin surface. By pressing with
A method of roughening the resin surface to increase its adhesion surface area has been used.

The present inventors have found that a film or sheet made of poly4-methyl-1-pentene with a roughened surface can be suitably used as a sheet for forming a roughened surface on the resin surface of the outer layer board. and has already applied for a patent (Japanese Patent Laid-Open No. 1982-
(See No. 32031).

The surface-roughened film or sheet made of poly-4-methyl-1-pentene has excellent heat resistance and rigidity, and is further pressed using a heat press to roughen the laminated surface that is in contact with the roughened sheet. It has excellent mold releasability from the resin surface after forming a rough surface on the resin surface of the laminate.
It is also suitably used as a release film for forming a rough surface of an outer layer board when producing the multilayer printed wiring board.

The inventors of the present invention continued their research to obtain a release film with even better rigidity while retesting the above-mentioned invention, and discovered that it was conventionally difficult to perform embossing after uniaxial stretching. The present invention was completed based on the knowledge that it is possible to form a suitable rough surface on the surface of the Tita 3MB film by performing embossing under a specific temperature and pressure after uniaxially stretching the film. I ended up doing it.

OBJECT OF THE INVENTION The object of the present invention is to provide a 3M release film that is even more rigid than the conventional release film made of poly(4-methylpentene).
An object of the present invention is to provide a release film manufactured by B and a method for manufacturing the same.

Summary of the Invention The release film of the present invention is made of a stretched polyester film having at least one surface roughened by embossing.
It is characterized by being made of methyl-1-butene film.

Further, the method for producing a release film of the present invention includes uniaxially stretching a poly-3-methyl-1-butene film melt-extruded from an extruder, and then applying the uniaxially stretched film to an embossing roll while heating under pressure. A feature of the film is that at least one surface of the film is roughened.

Since the release film of the present invention is a uniaxially stretched poly-3-methyl-1-butene film that is embossed, it exhibits excellent properties such as heat resistance and good release properties.

That is, according to the present invention, after uniaxially stretching a melt-extruded 3MB film, for example, 60-310
By embossing at least one surface, preferably both surfaces, of the film at a high temperature of 400 kg/nun2 at 2 Cl-400 kg/nun2, a release film with excellent rigidity and firmness can be obtained.

In recent years, there has been a tendency for such release films to have a high degree of heat resistance in order to increase wiring speed and improve reliability. The release film can withstand harsh conditions when manufacturing multilayer printed wiring boards, and does not lose its shape retention even when heated or pressurized during wiring board formation. Because of such heat resistance, that is, stiffness, after the prepreg is formed, it can be easily released from the prepreg surface, and the film does not wrinkle, and has excellent transferability.

Therefore, by using the release film of the present invention,
It becomes possible to easily manufacture a wiring board with a stable shape.

Detailed Description of the Invention Next, the release film of the present invention and the method for producing the release film will be specifically described.

The 3MB used in the present invention is 3 methyl-
In addition to homopolymers of 1-butene, 3-methyl-1-butene and other α-olefins, such as ethylene, propylene,
(-Brene, (-hexene, 1-octene, 1-decene, 1-tetradecene, tooctadecene, etc. with 2 to 2 carbon atoms)
Copolymers with 0 α-olefins can be used. In this case, it is preferable to use a 3-methyl-1-butene copolymer containing 60 mol% or more of repeating units derived from 3-methyl-1-butene.

Then, the melt flow rate of poly-3-methyl-1-butene used in the present invention (load + 5 kg).

temperature. 320°C) is preferably in the range of 0.1 to 500 sr/10 minutes. Melt flow rate is 0
．． If the time is less than 10/10 minutes, the melting point will be high, so
It may become difficult to mold. In addition, the melt flow rate and melt viscosity are low, making it difficult to mold, and the mechanical strength of films obtained using such polymers may also be low.

In the present invention, as 3MB, it is also possible to use modified 3MB in which part or all of it has been modified with an unsaturated carboxylic acid such as maleic anhydride.

In this case, modified 3MB can also be used in combination with unmodified 3MB.

In addition, 3MB used in the present invention contains various additives known to be added to polyolefins, such as heat-resistant stabilizers, weather-resistant stabilizers, rust inhibitors, copper damage-resistant stabilizers, and antistatic agents. may be blended within a range that does not impair the purpose of the present invention. Furthermore, in order to improve the mold releasability of the 3MB film, a small amount of mold releasability imparting agent such as silicone oil can be added to 3MB.

FIG. 1 does not schematically show an example of the process of manufacturing the release film of the present invention using 3MB as described above.

In FIG.
The original 3MB film melt-extruded through a T-die was once cooled to about 60°C by roll 2, and then heated to about 180°C by first heating roll 3.3'.
The stretching rolls 4, 4 are heated again while tension is applied between the first heating rolls 3, 3' and the stretching rolls 4, 4'.
4', the film is uniaxially stretched at a stretching ratio of usually 1 to 8 times, preferably 3 to 6 times. A 3MB film uniaxially stretched at such a magnification has improved rigidity, and cannot be subjected to surface roughening treatment using an embossing roll as it is. Therefore, in the present invention, 3MB after uniaxial stretching
The film is heated again to 100 to 290 with the second heating roll 5.
After heating to 160 to 260°C, it is fed into an embossing roll 6. In the present invention, it is preferable to arrange two to three second heating rolls 5 in order to sufficiently heat the 3MB film before it is embossed. By doing so, the 3MB film can be uniformly heated to a desired temperature.

The 3MB film heated as described above can also be embossed on both sides of the film at the same time by placing two embossing rolls in contact with both sides of the film. However, as shown in Fig. 1, after one side of the film is embossed, the film is heated again with the heating roll 7 of Node 3, and then the unembossed side is heated with another embossing roll. It is preferable to roughen the surface.

At this time, the pressure between the embossing roll 6 and the pressure roll 8 is usually set within the range of 20 to 400 kg/mm2, preferably 75 to 250 kg/mm2.

If the heating and pressing conditions of the 3MB film after uniaxial stretching are below the above range, the 3MB film may not be sufficiently roughened by the embossing roll.

By melting 3MB and extruding it into 111I as described above, a film having a thickness of 20 μm or more can usually be obtained. In the present invention, a film or sheet having a thickness within the range of 20 to 300 μm is easily used as the release film. Therefore, the release film of the present invention includes one having a thickness that is generally recognized as a sheet. In particular, a film of 30 to 50 μm is preferably used in view of ease of embossing and economic efficiency.

For example, the release film of the present invention produced by the method described above usually has an average surface roughness of 0.1 to 0.1.
It is within the range of 20 μm. If the average roughness is 0.1 μm or less, it is close to a smooth state, so the surface roughening treatment is insufficient for the purpose of a release film to increase the surface area, and the adhesive strength between the resin and prepreg after curing is poor. On the other hand, if it exceeds 20 μm,
1. Since the contact area between the cured resin and the release film increases more than necessary, the release film tends not to peel off smoothly.

Although there is no particular restriction on the material of the embossing roll used in the method of the present invention, since the 3MB film has high rigidity, it is preferable to use a metal roll, and the surface of such a metal roll is usually A film whose surface is roughened so that the surface roughness of the obtained film falls within the above range is preferably used.

A method for manufacturing a multilayer printed wiring board using the 3MB release film obtained in this manner will be described.

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

A copper foil 14' is placed on the press heating plate 11' via a cushion 12' and a jig 13'. Then, on this copper foil, a prepreg 15' is placed which is integrated with the copper foil by heat curing and is bonded to the inner layer circuit board. A release sheet] 6 is placed on top of this prepreg 15'. and,
With this release sheet 16 as the target surface, the prepreg] 5, copper foil 14, jig] 5, and Goongyong jade 16 were similarly placed on this release sheet roller in this order, and this laminate was further pressurized. , a press heating plate] is placed so that it can be heated.

Next, the above-mentioned laminate is heated and pressed using a press heating plate 1° 1.11', thereby forming two outer layer plates in which the copper foil and the prepreg are integrated.

Figure 3 shows the copper foil formed as described above]4゜14'
and prepreg 15.15'
FIG. 7 is a sectional view showing a state where the release film] 6 is peeled off from the mold release film 7'.

Figure 4 shows the configuration for producing a multilayer printed wiring board using the thus obtained outer layer board 17,17' with a roughened surface.The outer layer board is made of the same material as the cured resin. They are integrated by heating and pressurizing via a prepreg 15' made of resin. Figure 34 shows this state, and the surface of the cured resin of the outer layer board 1717' is roughened, so that a multilayer printed wiring board with excellent adhesive strength with prepreg 15# can be obtained. It is.

Heating when forming the outer layer board and multilayer printed wiring board is usually carried out at about 130 to 250°C, and the pressure is applied, for example, after preheating at 5 kg/mm2G for 30 to 60 minutes, and then at 30 kg/mm2G. It is preferable to press for 30 to 60 minutes. The release film of the present invention can be produced under the above-mentioned conditions, namely, heating temperature 270°C and pressure 80k.
It can withstand heating and pressure up to about g/mm2G.

As mentioned above, the release film of the present invention has roughened surfaces on both the front and back surfaces, so the contact surface of the release film of the prepreg is roughened during curing, and the outer layer plate is molded with an increased surface area. be done.

Effects of the Invention The release film of the present invention is a film obtained by roughening a uniaxially stretched 3MB film.

By using the uniaxially stretched 3MB as a release film, the rigidity of the film is significantly improved, and as a result, the rigidity of the unstretched 3MB film is 290 kg/ The stiffness of the uniaxially stretched 3MB film is 700mm.
This becomes clear from the fact that it reaches -1100 kg/n++++2.

Because the release film made of 3MB of the present invention has extremely high rigidity, the film surface does not wrinkle even when subjected to severe heating and pressure during press molding, and the rough surface formed on the film surface remains intact. It does not disappear and has an excellent transfer ratio. Therefore, by using the release film of the present invention, multilayer printing can be achieved by heating and pressurizing at high temperatures, which has recently required a high degree of heat resistance to increase wiring speed and improve reliability. Wiring boards can be manufactured stably.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples and Comparative Examples.
It shouldn't be measured.

5 The physical properties of the film in Table 1 were measured by the following method.

1, YS, TS, El, ... ASTM D 63
82, Gloss-IIs Z 87413, Surface roughness...T)IN 47B [14, Heat shrinkage rate A film sample having a marked line with a gap of about 10 cm was left in an atmosphere at a predetermined temperature for 30 minutes, then taken out and heated to 23°C.
The dimensions were measured after being left in an atmosphere of 50% RH for 30 minutes, and the shrinkage rate was calculated using the following formula.

ρ. -Dl Shrinkage rate = X100 (%) O D: Initial length between marked lines g: Length between marked lines after heating Example I 3-methyl-1- copolymerized with 4% by weight of L-decene Pelletized crystalline copolymer mainly composed of butene, 3
A polymethylbutene polymer film was extruded using a 90 mmφ extruder equipped with a cast die using a polymer having a melt flat rate of 25 as measured at 20° C. and a load of 5 kg. The temperature conditions of the extruder are cylinder temperature 300℃, die temperature 280℃.
A film of about 0.20 mm was extruded with 'C. The speed of the roll at this time was 3.6 m/min. After the extruded film was cooled and solidified with a chill roll at 85°C, it was then preheated with two preheating rolls at temperatures of 155°C and 220°C.

The preheated film was stretched 4 times by a stretching roll at a take-up speed of 14 ml for 1 minute. Next, this stretched film was preheated with a 160°C preheating roll, and then embossed on one side with a metal embossing roll with a press pressure of 150 kg/mm.The temperature of the embossing roll used at this time was 160°C. ℃, and this embossing roll is liquid honed.

Next, the other side of the film was embossed using another embossing roll. The roll temperature and press pressure were the same as those for embossing on the first surface]. Using the thus formed matte film, epoxy prepreg containing 30 μm copper foil and 0.8 mm glass fiber (resin content -52% by weight) was prepared.
Press molding was performed using the configuration shown in FIG.

For press forming, the initial press pressure was 15 kg/mm2.
Heated at 130℃ for 45 minutes, then pressed at a pressure of 40kg.
/nun2 for 1 hour at 180° C. to complete curing of the epoxy prepreg. This molded article was cooled to room temperature, peeled off, and peelability was evaluated.

As a result, the mold releasability after pressing was good.

Example 2 Crystalline 3-methyl-i- containing 7% by weight of 1-decene
The film was evaluated in the same manner as in Example 1 except that a butene copolymer was used, and as a result, the mold release properties of the film were good.

Comparative Example 1 3-Methyl 1- copolymerized with 6% by weight of n-octadecene
Using a crystalline copolymer mainly composed of pentene, which had a melt flow rate of 26 measured at 260°C and a load of 5 kg, extrusion was carried out using a cast die to a diameter of 90+ nmφ. A polymethylpentene polymer film was dispensed using a machine. The temperature conditions of the extruder are: 300°C in cylinder temperature, 2 in die temperature.
50 at 80°C. A czm T-die film was formed. The extruded film was cooled and solidified with a chill roll at 85 °C, and then the film was preheated with a preheat roll at 150 °C, followed by a pressing pressure of 100 kg/mm.
Embossing was performed on one side using a No. 2 embossing roll. The temperature of the embossing roll used at this time was 150℃
The surface of this embossing roll is corrugated and honed. Next, the other side was embossed using another embossing roll. The roll temperature and press pressure were the same as those used for embossing on the first side. Using the pine 1~ film formed in this way,
The same press bottom shape as in Example 1 was performed to evaluate the mold releasability.

As a result, the film can be peeled from the epoxy resin by The film was torn when released, and the mold releasability was poor.

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

0

[Brief explanation of drawings]

The first is a perspective view showing an example of a manufacturing apparatus for a surface roughened film of the present invention; FIGS. 1 to 3 are cross-sectional views showing the manufacturing process of an outer layer board of a multilayer printed wiring board; FIG. FIG. 3 is a cross-sectional view showing an example of a process of manufacturing a multilayer printed circuit board using the outer layer board. 1... Stretching machine, 2... Cooling roll, 3.3'... First heating roll, 4.4' - Stretching roll, 5... Second heating roll, 6... Embossing roll, 7...Third heating roll, 8...Pressure roll, 11,. 11. '・Press heating plate, 12.12'...Cushion month, 13.13'...Jig, 14, 14'...Copper foil, 2 15.15'...Briburek, 15"・Prepreg for adhesion , 16... Roughened release film, 17.17'
...Outer layer board, ]8...Inner layer board agent with copper circuit

Claims (5)

[Claims] (1) A release film made of a uniaxially stretched poly-3-methyl-1-butene film, at least one surface of which has been roughened by embossing. (2) The release film according to claim 1, wherein the average roughness of the film surface is 0.1 to 20 μm. (3) Poly 3-methyl-1- melt extruded from an extruder
A method for producing a release film, which comprises uniaxially stretching a butene film, and then roughening at least one surface of the film using an embossing roll while heating the uniaxially stretched film under pressure. (4) The manufacturing method according to claim 3, wherein the embossing is performed at a temperature of 60 to 310°C and a pressure of 20 to 400 kg/mm^2. (5) The manufacturing method according to claim 3, wherein the stretching ratio of the uniaxial stretching is within a range of 1 to 8 times.