JPH04348936A - Manufacture of laminated sheet - Google Patents

Abstract

PURPOSE:To reduce the development of the trouble of laminated sheet by smearing, produce the laminated sheet with high thickness accuracy at favorable productivity and reduce deformation under warpage. CONSTITUTION:A plurality of prepregs 1 in continuous form, each of which is prepared by impregnating base material with polybenzimidazole resin and drying it, are continuously fed and piled up together and further laminated to metal foil 2 in continuous form. The resultant laminate is continuously sent and passed through a double belt former 3 so as to be pressed between double belts 4 for integrally laminating and to cut in the required lengths in order to obtain laminated sheets A through re-heating. Since the thermal deformation temperature of the polybenzimidazole resin is high, the development of smear is a little. Since the above-mentioned engineering method is a continuous one, the productivity of the laminated sheet is enhanced. Further, the laminated sheet A is laminatingly formed one by one, the scattering in the thickness of the respective laminated sheets becomes small. By reheating after the thermal hardening of the polybenzimidazole resin, the deformation of the laminated sheet A under warpage can be reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminate used for manufacturing heat-resistant printed wiring boards.

0002

[Prior art] Electrical equipment, electronic equipment, computers,
BACKGROUND ART Heat-resistant printed wiring boards used in communication equipment and the like are commonly made from epoxy resin laminates. This epoxy resin laminate is made by impregnating a base material such as glass cloth with epoxy resin, drying it, and cutting it to the required size to create a prepreg, then stacking multiple sheets of prepreg and adding the required amount to one or both sides of the prepreg. It is manufactured by stacking copper foils cut to size and then heating and pressing them to form a laminate.

0003

[Problems to be Solved by the Invention] However, since epoxy resin has a relatively low heat distortion temperature, when drilling holes in an epoxy resin laminate, the epoxy resin may shrink due to shear heat generation at the inner periphery of the hole. There was a problem in that the resin melted and smear defects were likely to occur. In addition, when manufacturing as described above, the productivity is low because molding is a batch process, so about 15 sheets of prepreg and copper foil are stacked on top of each other with stainless steel plates interposed between them, and then this is placed on a hot platen. Laminate molding is carried out by stacking 20 to 30 layers of materials and pressurizing them.
When a large number of laminates are laminated at the same time in this way, a problem arises in that the thickness of each laminate becomes highly uneven.

The present invention has been made in view of the above points, and aims to reduce the occurrence of smear defects in laminates, and to manufacture laminates with high productivity and high thickness accuracy. This is the purpose.

[0005]

[Means for Solving the Problems] The method for manufacturing a laminate according to the present invention involves continuously feeding a plurality of long prepregs 1 prepared by impregnating and drying a polybenzimidazole resin into a long base material. At the same time, a long metal foil 2 is further overlapped, and this is continuously fed to the double belt forming machine 3.
It is characterized in that it is laminated and integrated by heating and pressurizing it between the double belts 4, cutting it into required dimensions, and then heating it again.

The present invention will be explained in detail below. Polybenzimidazole resin is an aromatic heat-resistant resin obtained by polymerizing diaminobenzidine and diphenyl isophthalate, and this polybenzimidazole resin is
It is used as a varnish with a concentration of about 30 to 60% by weight by dissolving it in a solvent such as NN' dimethylformamide, NN' dimethylacetamide, N-methylpyrrolidone, hexamethylsulfamide, dimethylsulfoxide, or the like. Further, as the base material, woven fabrics or non-woven fabrics such as glass fibers and synthetic fibers, paper, and other materials can be used, and are used in the form of a long belt wound into a roll. A long strip-shaped prepreg 1 can be prepared by impregnating this long base material with a polybenzimidazole resin varnish and heating and drying it. The prepreg 1 is wound into a roll and used as a long length.

[0007] In manufacturing a laminate, first, a plurality of prepregs 1 impregnated with polybenzimidazole resin are unrolled from a roll, and while being continuously fed, they are passed between laminating rolls 10 and stacked one on top of the other.
Furthermore, at this time, the metal foil 2 is let out from the roll and passed between the laminating rolls 12 while being continuously fed, and is overlapped on one or both outer surfaces of the stacked prepregs 1. As the metal foil 2, copper foil, aluminum foil, iron foil, nickel foil, zinc foil, other alloy foils, etc. can be used alone or in combination, and as a long strip wound into a roll. It is used. An adhesive layer may be provided on the side of the metal foil 2 that is overlapped with the prepreg 1.

[0008] In this way, a plurality of sheets of prepreg 1 impregnated with polybenzimidazole resin and metal foil 2 are stacked one on top of the other and are fed into the double belt molding machine 3 while being continuously fed. The double belt forming machine 3 is formed by providing a double belt 4 in a heating furnace 11 such as a tunnel type heating furnace. Further, the double belt 4 is formed by suspending a steel belt or other heat-resistant belt 13 between a plurality of pressure rolls 12 and making a pair of these belts face each other vertically. This double belt 4 is provided in the heating furnace 11, and by driving the pressure roll 12 to rotate as shown by the arrow in the figure, the belt 13 can be driven to run as shown by the arrow in the figure. Then, the prepreg 1 and the metal foil 2 are continuously fed into the double belt forming machine 3 and passed between the double belts 4, thereby heating and pressurizing them between the double belts 4. The polybenzimidazole resin is cured, and a plurality of prepregs 1 and metal foils 2 can be laminated and integrally formed. The molding conditions for this double belt molding machine 3 are a pressure of 1 to 40 kg/cm2 and a temperature of 140 kg/cm2.
It is preferable to set the molding time to ~180°C and 5 to 30 minutes. Then, while continuously feeding out the molded product from the double belt molding machine 3, it is cut into a cutter 14.
By cutting it into required dimensions, a polybenzimidazole resin laminate A having a metal foil 2 on its surface can be obtained.

However, if left as is, there is a risk that the laminate A will be severely warped, so in the present invention, the laminate A obtained by cutting with the cutter 14 is immediately passed through a heating furnace 15 to be reheated. . The conditions for this reheating are preferably that the heating temperature is 100 to 150°C and the heating time is about 20 to 60 minutes. In this way, it is possible to obtain a laminate A with small warping deformation by performing the reheating process.

0010

[Function] In the polybenzimidazole resin laminate A obtained as described above, since the polybenzimidazole resin has a high heat distortion temperature, it melts due to shear heat generated during drilling, resulting in smear defects. This can be reduced. In addition, laminate A can be manufactured with high productivity using a continuous method, and since laminate A is laminated one by one, it is possible to reduce variations in thickness between each laminate. can. Furthermore, since the laminate A formed by heating and curing the polybenzimidazole resin is heated again, the warpage of the laminate A can be reduced by heat treatment.

[0011]

EXAMPLES The present invention will now be illustrated by examples. Example 1 A prepreg was prepared by impregnating a base material made of a long glass cloth with a width of 105 cm and a thickness of 0.15 mm with a dimethylacetamide solution of polybenzimidazole resin at a concentration of 45% by weight, and drying it by heating. did. Three sheets of this prepreg are continuously fed and passed between the laminate rolls, and a long metal foil made of adhesive-coated copper foil with a thickness of 0.035 mm is continuously passed between the laminate rolls as shown in Figure 1. , Layer three sheets of prepreg and metal foil above and below them, and pass this through a double belt molding machine configured as shown in Figure 1, taking 10 minutes at a molding pressure of 10 kg/cm2 and a molding temperature of 180°C. It was laminated and molded. And this laminated board is 100cm
After cutting with a cutter every m, this is further heated at 120℃.
It was reheated by passing it through a heating furnace for 60 minutes to obtain a double-sided copper-clad polybenzimidazole resin laminate having a thickness of about 0.6 mm.

Comparative Example 1 A double-sided copper-clad polybenzimidazole resin laminate having a thickness of approximately 0.6 mm was obtained in the same manner as in Example 1, except that reheating was not performed. Comparative Example 2 A prepreg was prepared by impregnating a base material made of glass cloth with a length of 105 cm, a width of 105 cm, and a thickness of 0.15 mm with a 45% by weight solution of epoxy resin in methyloxytol and drying. Layer the required number of prepreg sheets and add 105cm in length and 105cm in width above and below.
m, metal foils made of copper foil with a thickness of 0.035 mm were stacked, and this stack was sandwiched between stainless steel plates with a thickness of 1 mm, 15 sets were inserted into the stages, and a molding pressure of 35 kg / cm2, temperature 170℃, time 120
A double-sided copper-clad epoxy resin laminate with a thickness of approximately 0.6 mm was obtained by heating and press-molding under conditions of 10 minutes.

[0013] When each of the laminates obtained in Example 1 and Comparative Examples 1 and 2 was drilled and inspected for the occurrence of smear, it was found that smear occurred in the laminate of Comparative Example 2, but in Example 2, smear occurred. No smear occurred in the laminates of Comparative Example 1 and Comparative Example 1. In addition, when the thickness of each of the 20 laminates obtained in Example 1 and Comparative Examples 1 and 2 was measured, the thickness of the laminate of Comparative Example 2 was 0.55 mm to 0.65 mm.
m, while the laminate of Comparative Example 1 has a width of 0.
．． The width was 58 to 0.61 mm, and the laminate of Example 1 had small variations in width and thickness of 0.58 to 0.61 mm.

[0014] Furthermore, when the warp dimensions of the laminates obtained in Example 1 and Comparative Examples 1 and 2 were measured, it was -4.0 mm for the laminate of Comparative Example 1, while that of Example 1 was -4.0 mm. -2.0 mm for the laminate of Comparative Example 2 (the laminate of Comparative Example 2 also -
2.0 mm), and the warpage was reduced.

[0015]

Effects of the Invention As described above, the present invention continuously feeds a long prepreg prepared by impregnating and drying a long base material with a polybenzimidazole resin, stacks a plurality of sheets, and then further coats a long metal foil. The polybenzimidazole resin is It has a high heat distortion temperature and can reduce the occurrence of smear defects caused by melting due to shear heat generated when drilling laminates, and laminates can be manufactured with high productivity using a continuous method. At the same time, since the laminates are molded one by one, it is possible to reduce the variation in thickness between each laminate and improve the accuracy of the thickness. Warpage and deformation of the laminate can be reduced by reheating after heating and curing.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of the manufacturing process of the present invention.

[Explanation of symbols]

1 Prepreg 2 Metal foil 3 Double belt forming machine 4 Double belt

Claims (1)

[Claims] [Claim 1] A long prepreg prepared by impregnating and drying a polybenzimidazole resin on a long base material is continuously fed and stacked, and then a long metal foil is further layered, and this is further continued. A method for manufacturing a laminate, which comprises: passing the laminate through a double belt forming machine while heating and pressurizing it between the double belts to integrate the laminate, cutting the laminate into a required size, and then heating it again.