JPH0793496B2 - Copper foil resin adhesive layer for copper clad laminates - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin adhesive layer for a paper-based copper-clad laminate excellent in punching workability.

(Prior Art) Recently, with the lightness, thinness, shortness, and miniaturization of electronic devices, MCL (copper clad laminate) capable of punching 1.78 mm pitch, 1.50 mm pitch IC holes or connector holes at room temperature is required. Has become.

Conventionally, in order to improve punching workability, there is a method of making a thermosetting resin impregnated into a fiber base material flexible or a method of using a low elastic paper base material.

(Problems to be solved by the invention) When the resin is made flexible by the above, punching workability and IC
Although crack resistance between the holes and the connector holes is improved, there is a problem that heat resistance, moisture resistance, silver migration resistance, electrolytic corrosion resistance, and solvent resistance are lowered.

The use of a low-elasticity paper substrate has a problem that warp characteristics and dimensional characteristics deteriorate.

It is an object of the present invention to provide a copper clad laminate having excellent punching workability and having no deterioration in other properties.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a paper-based copper-clad laminate in which a prepreg is further laminated and a copper foil is further laminated on the outer side thereof under heat and pressure to form a copper foil. And a prepreg are provided with a resin layer in which at least one of polyvinyl butyral, polybutadiene, polyester resin, and phenoxy resin is used in combination with a resole-type phenol formalin resin, and the rupture strain of the resin layer after heat-press molding is high. At 20 ℃
It is characterized by being 1.2% or more.

The resin layer formed between the copper foil and the prepreg is a copper foil adhesive or a resin sheet. The resin used is at least one of polyvinyl butyral, polybutadiene, polyester resin, and phenoxy resin, and is used in combination with a resol-type phenol formalin resin. Furthermore, in this resin layer, epoxy resin, phenol resin,
Melamine resin, urea resin and the like may be used together as long as the breaking strain of the resin layer after heating and pressurizing is 1.2% or more at 20 ° C. Further, the punching workability is also improved by selecting or modifying the resin used for the resin layer so that the stress-strain curve has a falling yield point after the resin layer is molded.
When a material is deformed by applying a certain amount of stress, it exhibits elastic deformation when the stress is small, but when the stress exceeds a certain limit, the stress (extension, deformation) suddenly increases with only a slight increase in the stress. The increase in size is called surrender. When the load is taken on the vertical axis and the strain is taken on the horizontal axis, the load increases and the strain increases proportionally while the load is small. However, when the load exceeds a certain limit, proportionality is lost. When the load is further increased, a slip phenomenon occurs in the material, which causes plastic deformation. Moreover, when the load is increased, the strain increases rapidly. The maximum value of the load is called the yield point, and once the yield point is exceeded, the load drops once and then only the strain increases under constant stress. In this case, the maximum value of the load is called the upper yield point, and the point where the load passes the maximum value and is once decreased is called the lower yield point. The material exhibiting such load (stress) -strain (elongation) is generally represented by a soft and tough (tough) material or a tenacious and tough material.

The above resin is applied as a solvent solution to a copper foil and dried to obtain a copper foil with an adhesive. A prepreg and an adhesive-attached copper foil are laminated and heat-pressed to form a copper-clad laminate.

In addition, after the above resin is formed into a sheet in advance, it is laminated between the copper foil and the prepreg, and otherwise the same as above, to obtain a copper clad laminate.

(Function) Cracks are likely to occur when punching at room temperature.
Cracks are less likely to occur if the surface layer portion has a large breaking strain.

According to the present invention, when a resin layer is provided on the surface layer portion to reduce the distortion at the time of punching and to select a resin having a large breaking strain, cracks are less likely to occur. When the breaking strain of the resin layer after molding is 1.2% or more at 20 ° C., the crack resistance is improved, and when it is 2.0% or more, the crack resistance is remarkably improved.

If the stress-strain curve of the resin layer after molding has a descending yield point, the resin layer absorbs the strain during punching.

(Example) (Example 1) Polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., BX-1) 150 parts by weight (abbreviated as "part" below), resol type phenol formalin resin (manufactured by Hitachi Chemical, UP-13N) 50 parts, unsaturated polyester 100 parts of resin (manufactured by Hitachi Chemical, Polyset) was dissolved in acetone to obtain an adhesive having a solid content of 18% by weight. This glue
35 μm copper foil (manufactured by Nippon Denshoku Co., Ltd.) is coated and dried at a solid content of about 30 g / m ² , and then prepreg (phenol resin impregnated paper)
Together with this, a copper clad laminate was obtained by heating and pressurizing by a conventional method. Separately, the above adhesive composition was heated and pressed in a mold to obtain a resin plate. Table 1 shows the properties of the obtained copper-clad laminate and the results of the tensile test of the resin plate.

(Example 2) 100 parts of polyvinyl butyral, 50 parts of resol type phenol formalin resin and 70 parts of unsaturated polyester resin were dissolved in acetone to obtain an adhesive having a solid content of 18% by weight. Less than,
A copper clad laminate was obtained in the same manner as in Example 1 to obtain a resin plate using the adhesive composition.

(Comparative Example) 100 parts of polyvinyl butyral and 50 parts of resol-type phenol-formalin resin were dissolved in acetone to give a solid content of 18% by weight.
The adhesive of was obtained. Thereafter, a copper clad laminate and a resin plate were obtained from the adhesive composition in the same manner as in Example 1. Table 1 shows the test results
Shown in.

(Test) The tensile test was carried out at 20 ° C. with a tensile speed of 50 mm / min and was measured using an extensometer.

Punching workability is 20 ℃, 80 tons press, hole pitch 1.78
Indicates the presence or absence of cracks, peeling, and whitening when punched in mm,
⊚ markedly good, ◯ good, Δ slightly bad, and × bad.

(Effects of the Invention) According to the present invention, the rupture strain of the resin layer in contact with the copper foil after heat-pressing is 1.2% or more at 20 ° C.
As shown in Table 1, the punching workability is good. 2.2% is excellent for waiting.

On the contrary, in the case of 1.0% as in the comparative example, cracking occurs.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Saito 1500 Ogawa, Shimodate, Ibaraki Shimodate, Hitachi Chemical Co., Ltd. Shimodate factory (72) Hiroyuki Kimura 1500, Ogawa, Shimodate, Ibaraki Hitachi Chemical Co., Ltd. Shimodate Factory (72) Inventor Yoshiyuki Narabe 1500 Ogawa, Shimodate City, Ibaraki Hitachi Chemical Co., Ltd. Shimodate Factory (56) Reference JP-A-58-204072 (JP, A) JP-A-1-237132 (JP, A)

Claims (2)

[Claims] 1. A paper-based copper-clad laminate in which a copper foil is further laminated on the outer surface of a prepreg and heat-pressed, and polyvinyl butyral, polybutadiene, polyester resin, or phenoxy resin is provided between the copper foil and the prepreg. A copper clad laminate characterized in that at least one or more of the above are provided with a resin layer in combination with a resol-type phenol formalin resin, and the strain at break after heat and pressure molding of the resin layer is 1.2% or more at 20 ° C. Copper foil resin adhesive layer for boards. 2. The copper foil resin adhesive layer for a copper-clad laminate according to claim 1, wherein a tensile stress-strain curve of the resin layer after molding has a descending yield point.