JPS6049422B2 - Manufacturing method for copper clad laminates - Google Patents

Description

Detailed Description of the Invention The present invention involves stacking a silane-modified polyethylene resin film, a base material whose surface has been treated with a silanol condensation catalyst and/or an epoxy resin prepreg containing a silanol condensation catalyst, and a copper foil and heating them under pressure. The present invention relates to a method for producing a copper-clad laminate, characterized in that forming and crosslinking are performed simultaneously.

Conventional copper-clad laminates are made using epoxy resin, glass cloth, etc.
It is well known that copper foil is layered on multiple sheets of prepreg made by impregnating and adhering to a base material such as paper or synthetic fiber cloth, and then molded by heating and pressing.

However, when these laminates are used as printed wiring boards for electrical equipment, they have a major drawback in that they do not have sufficient high frequency properties such as dielectric constant and dielectric loss tangent, and furthermore, their high frequency properties change due to humidity. In view of this, the present inventors
Conducted research on applying polyethylene resin, which is an excellent material for high-frequency properties, to laminates, and invented a method for producing copper-clad laminates that have better performance than conventional copper-clad laminates made of epoxy resin, etc. .

Since polyethylene resin is thermoplastic, it has poor heat resistance and cannot satisfy the solder heat resistance required for printed wiring boards.

It is known that crosslinking polyethylene improves its heat resistance, and in copper-clad laminates, the adhesion between the base material and the resin impregnated and adhered to is important. In general, polyethylene resins, especially ethylene homopolymers, have poor adhesion to glass, so by using a silane-modified polyethylene resin, which is a polyethylene resin grafted with a silane compound, this heat resistance and adhesion to glass can be improved. It was possible to be satisfied. To discuss this silane-modified polyethylene resin in detail, the polyethylene resin has the general formula RR'SIY.

(In the formula, R is a monovalent olefinic unsaturated group bonded to a silicon atom through a silicon-carbon bond and composed of carbon, hydrogen, and optionally oxygen, and each Y is hydrolyzable. (R' is a monovalent hydrocarbon group or group Y containing no aliphatic unsaturation. A silane-modified polyethylene resin can be obtained by reacting in the presence of a free radical generating compound. Polyethylene resins used in the present invention include polyethylene homopolymers, copolymers of ethylene containing 5% or more of ethylene, and other monomers copolymerizable with it, such as ethylene/vinyl acetate. Examples include copolymers, ethylene/propylene copolymers, and ethylene/acrylic acid copolymers.

A mixture of two or more of these can also be used. Among these, polyethylene homopolymer is most preferred from the viewpoint of high frequency characteristics. Further, in the general formula of the silane used in the method of the present invention, R is a monovalent olefinic unsaturated group composed of carbon, hydrogen, and optionally oxygen, and each Y is a hydrolyzable Organic groups such as methoxy, ethoxy, acetoxy, -ON=C(CH3)2 or -NHCH3.

The R'' group is a monovalent hydrocarbon group containing no fatty unsaturation or a group Y. Among these, those having three hydrolyzable groups are preferred, with vinyltriethoxysilane and vinyltrimethoxysilane being the most preferred. Preferred. Substances that function as silanol condensation catalysts are widely known, and any such substances can be used in the present invention. Examples of such substances include dibutyltin dilaurate, acetic acid, Stannous, stannous pyrofurylate, lead naphthenate, zinc pyrofurylate, iron 2-ethylcaproate,
There are metal salts of rubonic acids such as cobalt naphthenate and cobalt naphthenate, organometallic compounds such as esters and chelators of titanium, such as tetrabutyl titanate, tetranonyl titanate and bis(acetyl!acetonyl)-diisopropyl titanate, and ethylamine. , hexylamine, dibutylamine and pyridine, and acids such as mineral acids and fatty acids. Among these, organic tin compounds such as dibutyltin dilaurate and 5-dibutyltin diacetate are preferred. Further, as the base material used in the present invention, glass cloth, synthetic fiber cloth, paper, etc. can be used.

The surface treatment of the silanol condensation catalyst on the substrate uses a diluted solution of the silanol condensation catalyst with an organic solvent capable of dissolving the diranol condensation catalyst, but an emulsion solution of the silanol condensation catalyst can also be used. At this time, there is no limit to the concentration of the silanol condensation catalyst, but it is preferably 1% by volume or less. If the weight is 1% or more, the crosslinking speed of the silane-modified polyethylene resin film will become too fast when the laminate is heated and pressurized, and the silane-modified polyethylene resin will crosslink before the base material is sufficiently impregnated and adhered to the base material. Decreases adhesion to materials.

In carrying out the method of the present invention, a substrate is first immersed in a silanol condensation catalyst solution, or the solution is applied to the substrate and then air-dried or heated to evaporate the solvent sufficiently. Alternatively, a prepreg preparation method that is commonly used as a method of attaching an engineered poxy resin containing a silanol condensation catalyst to a substrate for a laminate may be used, and a prepreg in a moderately semi-cured state is produced after being impregnated with the resin. The epoxy resin used here may be a commonly used epoxy resin, and any curing agent, accelerator, and additive may be used. There is no limit to the ratio of the epoxy resin to the silane-modified polyethylene resin, but the higher the ratio of the silane-modified polyethylene resin, the better the high frequency characteristics, and the ratio can be selected depending on the required high frequency characteristics. The surface-treated base material and/or the epoxy resin prepreg containing the silanol condensation catalyst and the silane-modified polyethylene film are laminated to form a laminate of a desired thickness, and the outermost layer is covered with copper foil. Although these are pressurized and heated, there are no particular restrictions on the molding conditions. The temperature is about 150-200°C, the pressure is 30-100kg/
It is Clt. The copper-clad laminate thus obtained has superior high-frequency characteristics compared to conventional epoxy resin-based laminates, and furthermore, even when moisture is absorbed, the high-frequency characteristics change little. Furthermore, the silane-modified polyethylene resin film used adheres well to the base material or epoxy resin prepreg during hot-pressure molding, and is further supported by the silanol condensation catalyst applied to the surface of the base material or the silanol condensation catalyst in the epoxy resin prepreg. The crosslinking reaction progresses, resulting in a laminate with sufficient heat resistance. In this way, the present invention uses polyethylene resin with excellent high frequency characteristics in the field of copper-clad laminates, where conventional thermosetting resins such as epoxy resins have been used, thereby producing copper clad laminates that are inexpensive and have better high frequency characteristics. It manufactures stretched laminates. Specific examples of the present invention are shown below.

Example 1 High-density polyethylene (Showa Yuka Shorex MI=
0.89/1 powder) was sufficiently blended with 2 parts by weight of hinyltrimethoxysilane and 0.2 parts by weight of dicumyl peroxide using a stirrer, and the mixture was mixed under the following conditions. φ extruder (single screw,
The mixture was extruded and cut into strands (at a compression ratio of 3.5 and L/D=24) and granulated.

(Product A) Barrel band Head die ClC2C3C4HDl5Ol9O25 O22O22O22O (0C) Screw rotation speed 70r'Pml discharge amount: 23k9/H
rO This product A was made into a 200μ film using a 50rr0nφ extruder and an inflation die.

After sufficiently coating a 1% xylene solution of dibutyltin dilaurate, which is a silanol condensation catalyst, on a silane-treated glass woven fabric with a thickness of 0.21r1r1n, which is the base material, at 90 ° C. dried. The film, surface-treated glass woven fabric and 35μ copper foil were laminated as shown in FIG. 1, and press molding and crosslinking were carried out at a heating temperature of 170'C and a pressure of 80k9/Cd.
Table 1 shows the results of investigating the characteristics of this copper-clad laminate. Example 2 Low density polyethylene (Sumikasen, manufactured by Sumitomo Chemical, MI=1
．． 59/1 gin) and ethylene-acrylic acid copolymer (Dexon manufactured by Etsuso, MI = 1.5 Da/W min) (4
) was thoroughly blended with 1.5 parts by weight of vinyltriethoxysilane and 0.1 part by weight of dicumyl peroxide using a stirrer, and the mixture was granulated using the same extruder as in Example 1 under the following conditions. .

(Product B) Barrel band Head die ClC2C3C4HDl2Ol5O2O O23O2lO2lO (℃) Slew rotation speed 70 rpm 1 discharge amount: 20 kg/HrO
This product B was molded into a film with a thickness of 300 μm using an Injun φ extruder, an inflation machine, and 2 dies.

A 5% emulsion solution of dibutyltin diacetate as a silanol condensation catalyst was sufficiently applied to a 0.18 wm thick silane-treated glass woven fabric as a base material, and the powder was dried at 100°C x 1 to evaporate the water content. . The film, surface-treated glass woven fabric, and 35 μm copper foil were laminated as shown in FIG. 1, and press molding and crosslinking were performed at a heating temperature of 160′C and a pressure of 50 kg/Crl. Table 1 shows the results of investigating the characteristics of this copper-clad laminate. Example 3 (1) Epicote 1001 (Shell Chemical Co., Ltd.) 100 (parts by weight) (2) Dicyandiamide 4 (3) Benzyldimethylamine 0.2 (4) Dibutyltin dilaurate 2 (5) Methyl cellosolve 50 (6) Methyl ethyl ketone 50 A resin varnish is prepared by mixing and dissolving the materials (1) to (6) above.

Next, the resin varnish was applied to a silane-treated glass fiber woven fabric having a thickness of 0.18 wrm so that the resin adhesion amount was 4% by weight and dried to obtain a semi-cured prepreg. The prepreg, the same silane-modified high-density polyethylene resin film and copper foil as in Example 1 were superimposed as shown in Figure 1, and press molding and crosslinking were performed at a heating temperature of 170°C and a pressure of 50 kg/Cl for a heating time of 6 pieces. Ivy. Table 1 shows the properties of this copper-clad laminate. Characteristics of Examples 1 to 3 and Comparative Example (conventional product of glass vapor base material poxy copper clad laminate) As can be seen, the copper clad laminate made by the method of the present invention has a higher performance than the conventional copper clad laminate for high frequency use. It is possible to obtain a copper-clad laminate with good high-frequency characteristics and little change due to moisture absorption, and with excellent high-frequency characteristics.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the structure of a copper-clad laminate according to the present invention. 1 is a silane-modified polyethylene resin film, 2 is a base material surface-treated with a silanol condensation catalyst or an epoxy resin prepreg containing a silanol condensation catalyst, and 3 is a copper foil.

Claims (1)

[Claims] 1 Simultaneous molding and crosslinking treatment by stacking a silane-modified polyethylene resin film, a base material surface-treated with a silanol condensation catalyst and/or an epoxy resin prepreg containing a silanol condensation catalyst, and copper foil and heating under pressure. A method for manufacturing a copper-clad laminate, characterized by: