JPH058745B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is characterized by the fact that the silver migration phenomenon is less likely to occur (hereinafter referred to as
The present invention relates to a thermosetting resin composition for laminates used for printed circuit paper substrate phenolic resin laminates or copper-clad laminates (referred to as "excellent silver migration resistance"). [Prior Art] The case of a copper-clad laminate will be described below. Conventionally, printed circuit paper base phenolic resin copper-clad laminates are produced by impregnating and drying phenolic resin varnish into kraft paper or linter paper, laminating multiple sheets of the impregnated paper, and bonding them to one or both sides depending on the application. After adding agent-coated copper foil, it is manufactured by heating and pressure forming. In recent years, with the miniaturization and weight reduction of electronic devices, higher density has been sought in printed circuit wiring boards, and silver through holes and silver jumpers using conductive silver paint are also becoming more dense. It is becoming widely used as a method of implementation. However, with paper-based copper-clad laminates, when an electric field is applied between the silver electrodes formed on the surface of the laminate under temperature and humidity conditions, a phenomenon of silver migration between the silver electrodes occurs after a certain period of time. is well known. Many attempts have been made to electrochemically analyze this silver migration phenomenon, and it has been pointed out that the silver migration phenomenon differs depending on the insulating material. It is positioned as something where the phenomenon is likely to occur. However, as the density of printed circuit wiring boards increases, ensuring reliability is an important issue, but since this silver migration phenomenon has the potential to be a fatal defect for printed circuit wiring boards, At the production stage of wiring boards, various treatments that can suppress the silver migration phenomenon have been attempted and actually implemented.
There is a need for a paper-based copper-clad laminate that is highly dependent on the essential properties of the laminate and has excellent silver migration resistance. The present inventors conducted a detailed study on the silver migration phenomenon in paper-based phenolic resin copper clad plates, and found that the impregnation of the phenolic resin composition into the paper base material was a major factor. I came to find out. Two-coating is a well-known method for improving the impregnation method for paper, but this method reduces work efficiency, increases the amount of raw materials used, and affects the characteristics of the resulting copper-clad laminate. This is also unfavorable since mechanical properties are deteriorated. [Object of the invention] The present invention improves the above-mentioned problems and provides a paper-based phenolic resin copper-clad laminate with excellent silver migration resistance, which can be obtained by one coating. The purpose is to provide thermosetting resins. [Structure of the Invention] The present invention provides a phenolic resin used for a paper-based phenolic resin laminate or a copper-clad laminate having the general formula (However, n = 5 to 20, m = 2n + 1 or m = 2n - 1) This is a thermosetting resin composition for a laminate, characterized in that it contains a compound [ ]. The phenolic resin used in the thermosetting resin composition of the present invention is obtained by reacting phenols with formaldehyde, and the phenols include phenol, cresol, and alkylphenol. It is also possible to use oil-modified phenolic resins modified with oils such as tung oil, linseed oil, dehydrated castor oil, and cashew nut oil as the phenolic resin. Further, as the compound [], dimethylamide of saturated fatty acid or unsaturated fatty acid such as lauric acid dimethylamide and oleic acid dimethylamide is used. These fatty acid dimethylamides have good affinity with phenolic resins, and when added to phenolic resin varnishes, they have the effect of significantly lowering the viscosity of the phenolic resin varnishes. In addition, fatty acid dimethylamide has strong polarity and has good affinity with fibrous base materials such as linter paper and kraft paper used as base materials for copper-clad laminates, so when fatty acid dimethylamide is added to phenolic resin, fatty acid Compared to phenolic resins to which dimethylamide is not added, it is possible to impart significantly higher impregnating properties. The amount of compound [] added to the phenolic resin varnish is 0.1 to 10 parts by weight of compound [] per 100 parts by weight of phenolic resin in terms of solid content.
Preferably, 0.3 to 6 parts by weight is appropriate. [Effects of the Invention] As described above, the resin composition for laminates of the present invention can significantly improve the impregnating properties into paper base materials compared to conventional phenolic resins. Therefore, after laminating the impregnated paper, a high degree of silver migration resistance can be imparted to a paper-based phenolic resin laminate or copper-clad laminate that is heated and press-molded. Examples of the present invention are shown below. [Example] Synthesis Example 1000 g of phenol, 400 g of tung oil, and 1 g of p-toluenesulfonic acid were placed in a flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred and mixed. This mixture is then heated to 100 to 102 while stirring.
The mixture was heated to 0.degree. C. and reacted for 1 hour to obtain a phenol tung oil adduct. After adding 1 g of triethanolamine and stirring and mixing to neutralize, 250 g of paraformaldehyde (formaldehyde content 88%) and 40 g of hexamethylenetetramine were added, and heated while stirring and mixing at 90-95℃ for 3 hours. Made it react. Next, this mixture was dehydrated under reduced pressure by continuing to heat it under reduced pressure of 100 to 150 mmHg. When the temperature of the reaction product reached 100℃, the depressurization and heating were finished, and immediately 500g of toluene,
500 g of methanol was added, and the mixture was subsequently cooled to room temperature to obtain an oil-modified phenolic resin varnish (A) with a resin content of 60% by weight. Example 1 Oil-modified phenolic resin varnish obtained in Synthesis Example
1 part by weight of lauric acid dimethylamide was added to 100 parts by weight of the solid content of (A) and mixed with stirring to obtain a desired resin composition for laminate (B). Example 2 Oil-modified phenolic resin varnish obtained in Synthesis Example
6 parts by weight of lauric acid dimethylamide was added to 100 parts by weight of the solid content of (A) and mixed with stirring to obtain a desired resin composition for a laminate (C). Comparative Example 1 Oil-modified phenolic resin varnish obtained in Synthesis Example
0.08 parts by weight of lauric acid dimethylamide was added to 100 parts by weight of the solid content of (A) and mixed with stirring to obtain a resin composition for a laminate (D). Comparative Example 2 In addition, an oil-modified phenolic resin varnish (A) to which nothing was added was used as a resin composition for laminates (E). Using the four types of resin compositions for laminates shown in these examples and comparative examples, each was impregnated into 0.2 mm thick kraft paper and dried to obtain impregnated paper with a resin adhesion content of 45%. Next, after laminating 8 sheets of each of these impregnated papers,
After placing the adhesive-coated copper foil with a thickness of 0.035 mm with the adhesive side facing the impregnated paper, the pressure was 100 Kg/cm ² and the temperature was 165°C.
After heating and pressurizing for 100 minutes, copper-clad laminates b, c, d, and e having a thickness of 1.6 mm were obtained. After the copper foil of these copper-clad laminates b, c, d, and e was removed by etching, conductive silver paint was screen printed on the board surface using a circuit pattern as shown in FIG. 1 to prepare samples. 1, 2 in Figure 1
indicates a silver circuit. The distance between the opposing silver circuits is
It is 1.0mm. This sample was placed in a constant temperature and humidity chamber at a temperature of 40° C. and a humidity of 93%, and a DC voltage of 30 V was applied between the opposing electrodes and left for 500 hours. Next, for each sample, the insulation resistance between the electrodes was measured, and the change in appearance was determined. The results are shown in Table 1. Furthermore, the performance of the laminate was measured based on JIC C6481. The results are shown in Table 2. The copper-clad laminates obtained from the resin compositions shown in Examples 1 and 2 have a higher silver migration resistance than the copper-clad laminates obtained from the resin compositions shown in Comparative Examples 1 and 2. While the properties were significantly improved, there was almost no deterioration in other properties.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a silver circuit used in a silver migration test. 1 and 2 are silver circuits.

Claims (1)

[Claims] 1. A phenolic resin having the general formula (However, n = 5 to 20, m = 2n + 1 or m = 2n - 1) A thermosetting resin composition for a laminate, characterized in that it contains a compound [ ]. 2. The thermosetting resin composition for a laminate according to claim 1, wherein the amount of the compound [] added is 0.1 to 10% by weight based on the phenol resin.