JP3089536B2 - Molding cushion material, and method of molding a laminate using the molding cushion material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding cushion material used for molding a laminate, and a method of molding a laminate using the molding cushion material.

[0002]

2. Description of the Related Art A laminated board for a printed wiring board used for electronic equipment and electric equipment is prepared by, for example, arranging a metal foil such as a copper foil on the outside of a stacked prepreg to produce a laminate. Is sandwiched between molding plates to form a pressure-receiving body, and is formed by being heated and pressed between upper and lower heating plates. In this molding, a cushion material having flexibility is used for preventing damage to the molding plate and the hot plate and transmitting uniform pressure.

Conventionally, kraft paper or felt has been used as the cushion material. As a commercial product,
Specifically, the above kraft paper is 190 g / m ² type (manufactured by Tomagawa Seisakusho Co., Ltd .: storage elastic modulus 28 × 10 ⁷ d)
yn / cm ² (170 ° C.)), KG as the above felt
355ET (manufactured by Ichikawa Kaori Corporation: storage elastic modulus 17.2)
× 10 ⁷ dyn / cm ² (170 ° C.)).

However, in recent years, it has been required to form a large number of laminated plates between hot plates in order to improve productivity. When a large number of laminated plates are formed between hot plates using the above cushioning material, the laminated plate formed closest to the hot plate where the rate of temperature change during molding is large has cracks inside and Occur. This measling receives a remarkable temperature change from the hot platen,
It is caused by distortion due to a rapid temperature change, such as when shifting from a high temperature to a rapid cooling stage. This distortion is caused by the curing shrinkage, in which the resin of the prepreg heated under pressure is melted and further hardened, and the stress generated by the cooling shrinkage, in which the resin shrinks further in the cooling stage, and the temperature changes during heating and cooling. The stress is small where the ratio is small, and the stress becomes large and the buffer cannot be buffered where the rate of temperature change is large. In other words, due to the resin curing shrinkage during molding and the shrinkage due to cooling, the laminate formed closest to the hot plate will peel off at the intersection of the warp and weft constituting the base material, cracking will occur, and Occurs.

[0005]

As a solution to this problem,
The inventor of the present application disclosed in Japanese Patent Application No. 7-32755 that the cushion material had a storage elastic modulus of 1 × 10 ⁷ dyn / cm ² or more.
It has been proposed to use a fluororubber of not more than × 10 ⁷ dyn / cm 2.

In recent years, effective utilization of resources has been desired, and it has been demanded that the cushion material can be used a plurality of times. The use of the fluororubber in the above range can prevent the occurrence of the measling, but when used many times, for example, ten times or more, a residue of bubbles called a void is easily generated in the formed laminate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a cushioning material having good durability and a cushioning material for molding many times when forming a laminate. It is an object of the present invention to provide a method of forming a laminated board that does not generate voids even when used.

Further, in addition to the above objects, it is another object of the present invention to provide a molding cushion material that does not cause measling, and a method of molding a laminated board.

[0009]

According to a first aspect of the present invention, there is provided a molding cushion material comprising: a core layer (1) containing fluorine rubber as a main component; and an impact-resistant material on both sides of the core layer (1). in tabular molding cushioning material comprising a surface layer (2) having a
There is an aramid nonwoven fabric on both sides of this core layer (1).
Intermediate layer (2a), and on both sides of the intermediate layer (2a)
Surface layer made of glass substrate containing fluororubber (2)
Characterized in that it comprises a.

According to a second aspect of the present invention, there is provided the molding cushion material according to the first aspect, wherein the core layer 2 has a storage elastic modulus of 1 × 10 ⁷ d at a molding temperature.
It is in the range of yn / cm ² or more and 3 × 10 ⁷ dyn / cm ² or less.

According to a third aspect of the present invention, there is provided a method of forming a laminated plate, comprising: a laminated body having a metal foil disposed outside a laminated prepreg; and body 7, further the first aspect outside the the pressure-receiving member 7
Alternatively, the molding cushion material 8 according to the second aspect is provided, and is heated and pressed between the hot plates 9 and 9.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional perspective view of a molding cushion material according to a reference embodiment, and FIG. 2 is a sectional perspective view of a molding cushion material according to an embodiment of the present invention. FIG. 3 is an exploded cross-sectional view showing the configuration inside the hot platens for each layer when the method for forming a laminated plate of the present invention is performed.

The molding cushion material of the present invention will be described. The cushioning material for molding is used when molding a laminate, and has a flat plate shape. Shown to forming <br/> form cushion material 1 is the core layer 1, and, a layer structure of three layers comprising a surface layer 2 on both sides of the core layer 1.

The core layer 1 is mainly formed of fluoro rubber as a constituent material. The necessary flexibility can be imparted to the cushion material 8 for molding by the fluororubber.
In particular, the storage elastic modulus at the molding temperature of the core layer 1 is 1 × 10
It is preferably in the range of ⁷ dyn / cm ² or more and 3 × 10 ⁷ dyn / cm ² or less. Storage modulus is 1 × 10 ⁷
If it is not more than dyn / cm 2, the flexibility of the molding cushion material 8 is reduced, and the absorption of distortion generated during molding is reduced. When the storage elastic modulus is 3 × 10 ⁷ dyn / cm ² or more, the transmission of pressure during molding tends to be uneven.
Note that the storage elastic modulus is a value indicating an elastic modulus when intermittently pulled, and is measured using a viscoelasticity measuring device with an initial load of 100 g and a cycle of a frequency of 1 Hz. is there.

The surface layer 2 has impact resistance, and can impart strength to the molding cushion material 8. Examples of the constituent material of the surface layer 2 include a glass substrate containing fluorine rubber, a metal foil, and an aramid nonwoven fabric. The above-mentioned glass substrate containing fluororubber is obtained by impregnating the glass substrate with fluororubber and then heating and pressing. Examples of the metal foil include a copper foil and an aluminum foil. The thickness of the metal foil is 9 to 70 μm,
The aluminum foil is suitably 20 to 100 μm. The above-mentioned aramid nonwoven fabric is prepared by making aramid fibers together with a binder and the like, then drying and calendering.

[0016] With the above layer configuration, the molding cushion material has good durability. Core layer 1 of molding cushion material 8
Is flexible, but when pressure is repeatedly applied, breakage such as tearing or tearing is likely to occur. When this breakage occurs, the pressure transmission becomes non-uniform, which causes voids in the laminate. Since the molding cushion material of the present invention includes the surface layer 2 having impact resistance, it is possible to protect the fluoro rubber from the pressure repeatedly applied. As a result, even if the molding cushion material of the present invention is repeatedly used for molding, the fluororubber is not damaged, so that no void is generated in the laminate.

Next, a method for producing the molding cushion material 8 will be described. The fluororubber sheet to be used as the core layer 1 is prepared by, for example, mixing carbon black, magnesium oxide, and a vulcanizing agent with fluororubber as necessary, kneading the mixture, and extruding the mixture with an extruder roll. Make it. A glass substrate is impregnated with fluoro rubber, and a dried fluoro rubber glass substrate prepreg is laid on top and bottom of the fluoro rubber sheet, sandwiched between stainless steel forming plates, and heated and pressed to be integrated. Further, instead of the fluororubber glass base material prepreg, a metal foil or an aramid nonwoven fabric is overlaid on the upper and lower sides of the fluororubber sheet, sandwiched between stainless steel forming plates, and integrated by heating and pressing.

[0018] showing an embodiment of molding the cushion material in FIG. The molding cushion material 8 includes a core layer 1 mainly composed of fluororubber, an intermediate layer 2a made of an aramid nonwoven fabric on both sides of the core layer 1, and a glass base containing fluorine rubber on both sides of the intermediate layer 2a. A surface layer 2 made of a material is provided. With the above layer configuration, flexibility and impact resistance increase. Although aramid nonwoven fabric which may fiber is scattered, Ru can be prevented when the aramid nonwoven fabric and the intermediate layer 2a fiber scattering of. The layer configuration may be appropriately selected depending on the flexibility required by the molding cushion material.

Next, a method for forming a laminate according to the present invention will be described with reference to FIG. A plurality of prepregs 3 in which a resin varnish is impregnated into a substrate are stacked, and a metal foil 4 such as a copper foil is disposed on one or both of the outsides to form a laminate 5. Are sandwiched between the forming plates 6, and a plurality of these are stacked to form a pressure-receiving body 7. As the base material of the prepreg 3, woven fabric, nonwoven fabric or mat of inorganic fibers such as glass and asbestos, organic synthetic fibers such as polyamide, polyvinyl alcohol, polyester and polyacryl, and natural fibers such as pulp paper and cotton are used. . The resin varnish impregnated in the base material is a resin varnish containing a thermosetting resin such as an epoxy resin, a phenol resin, a melamine resin, and a polyimide resin as a main component and, if necessary, a coupling agent and a flame retardant added. can do. As the forming plate 6, a stainless steel plate having a thickness of 1 to 3 mm or a mirror plate obtained by plating the surface of an iron plate with chrome is used.

Further, the above-mentioned molding cushion material 8 is disposed outside the pressure-receiving body 7 and is heated and pressed between the hot plates 9 and 9. By the heating and pressurizing, the resin of the prepreg 3 is completely cured, and a laminate is obtained. According to the method of forming a laminated board of the present invention, voids are not generated in the laminated board even if the molding cushion material 8 is used many times.

[0021]

The effects of the present invention will be described below with reference to examples and comparative examples.

Reference Example 1 A molding cushion material was produced as follows. First, fluororubber is described as 100 parts by weight or less, carbon black (RT Vanderblt Co. Inc .: T
Hermax), 15 parts of magnesium oxide (manufactured by Showa Chemical Industry Co., Ltd .: Kyowaguma 30) and 3 parts of a vulcanizing agent (manufactured by Daikin Industries, Ltd .: V3) to produce a fluororubber compound, which is extruded. Thickness of 0.
A 03 mm fluorine rubber sheet was obtained. The storage elastic modulus at 170 ° C. of this fluororubber sheet was measured with a viscoelasticity meter (Type F-3, manufactured by Iwamoto Seisakusho KK) to be 1.1 × 10 ⁷ dyn / cm ² .

Glass substrate (manufactured by Asahi Schwebel Co., Ltd .:
ASCO216LAS450) was impregnated with the above-mentioned fluororubber and dried at 200 ° C. to obtain a fluororubber glass substrate prepreg having a fluororubber content of 40% by weight. This fluororubber glass substrate prepreg is stacked one by one on the upper and lower sides of the fluororubber sheet, sandwiched between stainless steel forming plates, and heated and pressed at a temperature of 160 ° C. and a pressure of 30 kg / cm ² for 1 hour to form a fluororubber sheet. A three-layered molding cushion material having a core layer and a glass substrate containing fluorine rubber as a surface layer was obtained.

The laminate was formed as follows. Epoxy resin (manufactured by Toto Kasei Co., Ltd .: YDB500, solid content 8)
100 parts by weight), 3 parts of dicyandiamide (manufactured by Nippon Carbide Co., Ltd.), 0.2 parts of 2 ethyl 4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd .: 2E4MZ),
A resin varnish was prepared using dimethylformamide (DMF) as a diluent, and this resin varnish was impregnated into a glass cloth base material (manufactured by Asahi Schwebel Co., Ltd .: 7628AS450S), dried at 170 ° C., and dried to a half of resin content 40%. A cured prepreg was obtained.

Eight prepregs were used, and a copper foil having a thickness of 35 μm was laminated on both outer sides as a metal foil to form a laminate. Ten sets of the laminated bodies were alternately sandwiched between the forming plates to form a pressure-receiving body. One sheet of the above-mentioned cushioning material for molding is arranged on both sides of the above-mentioned pressure-receiving body, and heated and pressed at a temperature of 170 ° C. and a pressure of 30 kg / cm ² for 2 hours, and then cooled under the same pressure. To form a laminate.

Further, the cushioning material used above was repeatedly used up to 200 times continuously to form a laminate. Visual observation of the molding cushion material showed no breakage or tear.

The evaluation of voids and measling of the formed laminate was performed as follows. The above cushioning material for molding
The laminated board obtained by using 10 times, the laminated board obtained by using the cushioning material for molding 10 times, and the cushioning material for molding by 200 times
Of the laminates obtained by repeated use, a laminate formed at a position closest to the hot platen was extracted. The copper foil on the surface of these laminated plates was removed by etching, and the occurrence of measling occurring at the intersection of the warp and weft of the voids and glass cloth was visually and visually confirmed. The location where voids and measling occurred was not confirmed. Table 1 shows the results.
Shown in

Reference Example 2 A cushion material for molding was produced as follows. A thickness of 2 mm above and below a fluororubber sheet prepared in the same manner as in Reference Example 1.
The aramid nonwoven fabrics were stacked one by one and heated and pressed in the same manner as in Reference Example 1 to obtain a three-layered cushioning material having a fluorine rubber sheet as a core layer and an aramid nonwoven fabric as a surface layer.

Except for using the above cushioning material for molding,
In the same manner as in Reference Example 1, the molding cushion material was continuously and repeatedly used up to 200 times to form a laminate. Visual observation of the molding cushion material showed no breakage or tear. Further, in the same manner as in Reference Example 1, voids and measling of the formed laminate were evaluated. The location where voids and measling occurred was not confirmed. Table 1 shows the results.

Reference Example 3 A molding cushion material was produced as follows. 35 μm in thickness above and below the fluororubber sheet produced in the same manner as in Reference Example 1.
m of copper foil were stacked one by one and heated and pressed in the same manner as in Reference Example 1 to obtain a three-layered cushioning material having a fluorine rubber sheet as a core layer and a copper foil as a surface layer.

A laminated board was formed by repeatedly using the forming cushion material up to 200 times in the same manner as in Example 1 except that the above-mentioned forming cushion material was used. Visual observation of the molding cushion material showed no breakage or tear. Further, in the same manner as in Reference Example 1, voids and measling of the formed laminate were evaluated. The location where voids and measling occurred was not confirmed. Table 1 shows the results.

Example 1 A cushion material for molding was produced as follows. A thickness of 2 mm above and below a fluororubber sheet prepared in the same manner as in Reference Example 1.
Aramid non-woven fabric one by one, and further above and below,
A fluororubber-containing glass substrate produced in the same manner as in Reference Example 1 was overlaid and heated and pressurized in the same manner as in Reference Example 1 to form a fluororubber sheet as a core layer, an aramid nonwoven fabric as an intermediate layer, and a fluororubber-containing glass substrate. A five-layered cushioning material having the material as a surface layer was obtained.

Except for using the above cushioning material for molding,
In the same manner as in Reference Example 1, the molding cushion material was repeatedly used up to 200 times continuously to form a laminate. Visual observation of the molding cushion material showed no breakage or tear. Further, in the same manner as in Reference Example 1, voids and measling of the formed laminate were evaluated. The location where voids and measling occurred was not confirmed. Table 1 shows the results.

Comparative Example 1 A laminate was formed in the same manner as in Reference Example 1 except that the fluororubber sheet prepared in Reference Example 1 was used alone as a molding cushion material. The used cushioning material for molding was continuously and repeatedly used to form a laminated plate, and the molding cushioning material was visually observed. As a result, tearing or tearing occurred 10 times after use, and voids were generated in the laminated plate. Table 1 shows the results.

Comparative Example 2 A molding cushion material was produced as follows. 2mm thick
On the upper and lower sides of the aramid nonwoven fabric, the fluororubber sheets produced in the same manner as in Reference Example 1 are stacked one by one, and heated and pressed under the same conditions as in Reference Example 1, so that the aramid nonwoven fabric as the core layer and the fluororubber sheet as the surface layer. Thus, a three-layered cushioning material for molding was obtained. Reference Example 1 except that the above-mentioned molding cushion material was used.
A laminate was formed in the same manner as in the above. Using the molding cushion material used continuously and repeatedly, forming a laminate,
When the molding cushion material was visually observed, tearing and tearing occurred 10 times after use, and voids were generated in the laminate. Table 1 shows the results.

Comparative Example 3 190 g / m ² type kraft paper (manufactured by Tomagawa Paper Mill, storage elastic modulus 28 × 1) was used as a cushioning material for molding.
^{0 7 dyn / cm 2 (170} ℃) except that used 10 sheets in the same manner as in Reference Example 1, it was molded laminates. Using the used molding cushion material continuously and repeatedly, forming a laminate, and visually observing the molding cushion material,
After five uses, tearing and tearing occurred, and a number of voids occurred in the tenth-use laminate. Table 1 shows the results.

[0037]

[Table 1]

[0038]

The cushioning material according to the first aspect of the present invention is provided with the surface layer 2 having impact resistance, so that the fluororubber can be protected from the pressure applied repeatedly, so that the durability is good. is there. As a result, even if the molding cushion material of the present invention is repeatedly used for molding, the fluororubber is not damaged, so that no void is generated in the laminate.

Further, in addition to the above effects, the molding cushion material according to the second aspect of the present invention has a storage elastic modulus at the molding temperature of the core layer 1 of 1 × 10 ⁷ dyn / cm ² or more.
Since it is in the range of 10 ⁷ dyn / cm ² or less, no measling occurs in the formed laminate.

According to the method for forming a laminated board according to the third aspect of the present invention, since the molding cushion material 8 according to the first or second aspect is used, voids are generated in the laminated board even when used many times. Never do.

[Brief description of the drawings]

FIG. 1 is a cross-sectional perspective view of a molding cushion material according to an embodiment serving as a reference of the present invention.

FIG. 2 is a sectional perspective view of a molding cushion material according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a configuration inside a hot plate in a disassembled state for each layer when the method of forming a laminate of the present invention is performed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core layer 2 Surface layer 2a Intermediate layer 3 Prepreg 4 Metal foil 5 Laminate 6 Forming plate 7 Pressed object 8 Molding cushion material 9 Hot plate

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI B29L 9:00 31:34 (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 B29C 43/00-43/58 H05K 3/00-3/46

Claims (3)

(57) [Claims] 1. A core layer (1) containing fluororubber as a main component,
And a flat-shaped cushioning material having an impact-resistant surface layer (2) on both sides of the core layer (1) ,
Intermediate layers of aramid nonwoven fabric on both sides of this core layer (1)
(2a) and a fluorine resin on both sides of the intermediate layer (2a).
A cushioning material for molding, comprising a surface layer (2) made of a glass substrate containing a rubber. 2. The core layer (2) has a storage elastic modulus at a molding temperature of 1 × 10 ⁷ dyn / cm ² or more and 3 × 10 ⁷ d.
^2. The molding cushion material according to claim 1, wherein the thickness is not more than yn / cm ² . 3. A laminated body (5) in which a metal foil (4) is disposed outside the laminated prepreg (3), and the laminated body (5) is sandwiched between forming plates (6) to form a pressure-receiving body (7). ), and further, the claim 1 or claim outside this the pressure-receiving member (7)
2. A method for forming a laminate, comprising: disposing the molding cushion material (8) according to 2 above; and heating and pressing the same between the hot plates (9) and (9).