JPS6248532A - Manufacture of laminated sheet - Google Patents

Abstract

PURPOSE:To permit to manufacture the titled sheet prominent in punching workability and warping characteristic by a method wherein the molding thereof is effected by combining two kinds of base materials having different containing amount of alpha-cellulose respectively. CONSTITUTION:A base material, consisting of a base paper for a laminated sheet made by making cellulose fiber containing 88% or more of alpha-cellulose impregnated and adhered with a predetermined amount of thermocuring resin, and another base material, consisting of a base paper for the laminated sheet made by making cellulose fiber containing 75-88% of alpha-cellulose impregnated and adhered with a predetermined amount of thermocuring resin, are combined to mold the tille sheet. Here, the laminated sheet having well-balanced punching workability and warping characteristic can be made by combining the surface layer of laminated sheet made by the base material using a base paper containing 88% or more of alpha-cellulose and the inner layer of base material using a base paper containing 75-88% of alpha-cellulose. According to this method, surface crack may be improved and warping behavior may be stabilized.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for manufacturing a laminate.

(Conventional technology) The electronic equipment industry has developed significantly in recent years, and with the increasing density of printed wiring boards used in electronic equipment, automatic component mounting technology has also progressed, and printed wiring boards have become more demanding in their dimensional accuracy. is required. In order to meet this demand, low-temperature punching processing has been carried out. Due to the automation of printed wiring board manufacturing and the increasing sophistication of automatic component mounting, there is a demand for laminates with good warpage characteristics.

Conventionally, thermosetting resins have been modified to make them more flexible in order to improve their punching properties, but there has been little research into the base paper used. The composition, density, combination, etc. of the base paper have a great effect on the overall thickness of the base paper, and it is known that good results can be obtained by using a base paper containing 75% or more and less than 88% of α-cellulose.

In addition, from the point of view of punching processability, α-cellulose content is 88%.
It is said that base paper containing above is good.

(An intermediate point solved by the invention) However, there is a problem with the laminated machine μ punching processability using base paper containing α-cellulose of 75% or more to less than 88%, and The base paper contained has poor dimensional stability against heat and poor warping properties. This tendency is particularly noticeable in single-sided copper-clad laminates that use copper foil all over.

The present invention provides a method for manufacturing a thermosetting resin laminate having good punching workability and warpage characteristics.

(Means for Solving the Problems) The present invention uses base paper for a laminating machine made from linear M fibers containing 88% or more of α-cellulose, and uses a base paper for a laminating machine to which a predetermined amount of thermosetting resin is impregnated and adhered. 75% alpha cellulose
A product made by making a paper from A m elementary fibers containing 88% or more / f
This is a method for manufacturing a multi-board board, which is characterized by combining and molding a base material made by impregnating and adhering a predetermined amount of thermosetting resin to base paper for an i-board. Generally, as base paper for thermosetting laminates, base paper made from linter pulp '1 or base paper made from wood pulp is used. The former is α-cellulose 7 minutes is 9
8% or more, but the latter depends on the type of raw materials, cooking method, etc.
α-cellulose 7 minutes is different. α-Cellulose 7% has a great effect on punching workability and warping properties, and when using a base paper containing 75% or more to less than 88% α-Cellulose 7%, warpage properties and dimensional stability are good. Are known.

-Force, α-Cellulose 7 min is 88% or more, the punching workability is good. This is because components other than α-cellulose, such as hemicellulose and lignin, strengthen the bonds between fibers.
Although the dimensional change due to heat is reduced, the elastic modulus of the paper increases, so the shearing force during punching becomes high and the punching workability deteriorates. Therefore, in the present invention, 88% α-cellulose
Base material using base paper containing the above and α-cellulose gold 75
It has been discovered that laminated sheet metal can be manufactured with good punching workability and warpage properties by using a combination of base materials made of base paper containing 88% or more and less than 88%. By combining the respective base materials, the effect is greater than when the base materials are used alone.

In particular, if a base paper containing 88% or more of α-cellulose 7 is used in the surface layer on the side of the punching bin to be punched, surface cracks will be small and the punching processability will be good.

Therefore, the method for achieving a well-balanced and good punching processability and warpage property is to use a base paper containing 88% or more of α-cellulose to form the surface layer of the plate,
This is a combination in which the inner layer is a base material using a base paper containing 5% or more and less than 88%. This improves surface cracking and stabilizes warping behavior.

For α-cellulose 7 minutes, if it is less than 75%, the moisture resistance and electrical properties will deteriorate significantly. This is thought to be because hemicellulose is highly hydrophilic. The density of paper is known to be a critical factor for impregnation with thermosetting resin, and when resin impregnation is insufficient, delamination during punching and moisture resistance deteriorate. Therefore, the lower the paper density, the better the impregnation. However, in the process of impregnating and drying the resin, a certain degree of strength is required, so the density of the paper is 0.4 to 0.
68 g/an', preferably 0.45 to α55 g/-.

Further, the other physical properties of the paper may be those of general base paper for laminating machines.

The thermosetting resin used as the impregnating material is phenolic resin,
Made of evogishi resin, polyester resin, melamine resin, etc.
Any of these modified resins may be used, and the resins may be used alone or in combination. In particular, flexible phenolic resins modified with tung oil, polybutadiene, polyether, and polyester, flexible epoxy resins modified with dimer acid, higher fatty acids such as adipic acid, and ether glycols such as diethylene glycol are used. When a saturated polyester resin is used, the punching processability becomes good and low-temperature punching becomes possible. In addition, by adding flame retardants to these resins,
Using reacted thermosetting resins, flame-retardant laminates can be produced.

Example 1 Tung oil and meta-cresol were reacted under an acid catalyst, and then paraformaldehyde was converted into a sol under an alkali catalyst, and the resol-formed resin containing 28% of the tung oil modified was used as a varnish for impregnation.
Treated in advance with water-bathable phenolic resin (m Lipid: *i
A kraft paper containing 95% α-cellulose (12%) was impregnated with the above-mentioned impregnating varnish to a resin adhesion of 50% and dried, and 7 was used as a base material (A base material). First, kraft paper containing 85% Shiyu α-cellulose O'e, previously treated with a water-soluble phenol resin (fatty *n12%), was impregnated with the above impregnating varnish so that 50% of the resin adhesion became trapped, and then dried. (B base material) was combined with a copper foil with adhesive as shown in the first layer, and heated and pressed to obtain a 1.6 mm single-sided steel clad laminate. The characteristics of copper-clad laminates are shown in the attached table.

Example 2 A base material using kraft paper containing 75% of α-cellulose in total as shown in Example 1 and kraft paper containing 85% α-cellulose 2 as the surface layer and inner layer using A base material niB
The base material was constructed and combined with adhesive-coated steel foil as shown in Figure 2, and heated and pressed to obtain a single-sided steel clad laminate with a size of 6 m and 111 mm.The characteristics of the copper clad laminate are all shown in the attached table.

Comparative Example 1 A single-sided steel clad laminate with a thickness of 1.6 mm was obtained by heating and pressing the A base material shown in Example 1 and using kraft paper containing 95% α-cellulose.Copper clad laminate I- The characteristics of the board are shown in the attached table.

Comparative Example 2 A single-sided steel-clad laminate having a diameter of 1°61111 was obtained by heating and pressing the B base material made of kraft paper containing 85% α-cellulose shown in Example 1. The characteristics of copper-clad laminates are shown in the attached table.

Below margin Note 1) Punching workability was measured according to the ASTM method.

Note 2) Warpage characteristics are 330 x 480 mro dimensions with residual copper ratio 5
0% pattern was prepared and placed in a UV curing furnace (substrate temperature 80°C).
℃, 6 mercury lamps, conveyor speed 5 m) five times, the sample was placed flat on a surface plate, and the height of warpage was measured. The direction in which the copper foil surface becomes the bevel surface was defined as a positive value, and the distance between the bottom surface of the board at the maximum convexity and the surface plate was defined as the amount of warpage.

The following margins (effects of the invention) As explained above, in detail, a base material using a base paper made from cellulose fiber containing 88% or more of α-cellulose and a cellulose material containing 75% or more but less than 88% of α-cellulose By combining a base material made of a base paper made from fibers, a laminate with excellent punching properties can be produced.

[Brief explanation of the drawing]

@ Figures 1 and 2 are front views showing the structure of the base material of the laminate. Explanation of symbols 1 Steel with adhesive (2A base material (α cellulose 3 B base material)
α Cellulose 95%) Cellulose 85%)

Claims (1)

[Scope of Claims] 1. A base paper made from cellulose fiber containing 88% or more of α-cellulose, which is impregnated with a predetermined amount of thermosetting resin, and α-cellulose is applied to the base paper. A method for manufacturing a laminate, which comprises combining and molding a base material made of a base paper for a laminate made from cellulose fiber containing 75% or more to less than 88% and impregnated with a predetermined amount of a thermosetting resin. . 2. Using base paper for laminates made from cellulose fibers containing 88% or more of α-cellulose, the substrate is impregnated with a predetermined amount of thermosetting resin and becomes the surface layer of the laminate. A method for manufacturing a laminate according to scope 1.