JPH042612B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Fields The present invention has properties such as room-temperature punching workability, flame retardancy, heat resistance,
This invention relates to a method for manufacturing flame-retardant phenolic resin laminates that require high electrical properties. BACKGROUND OF THE INVENTION Recently, as the use of flame-retardant phenolic resin laminates as electric insulating substrates in consumer electronics has increased, the demand for high quality and low cost has become stronger. In order to obtain a flame-retardant phenolic resin laminate with advanced electrical properties, the process of impregnating and drying the base material with a thermosetting resin is repeated twice, as an undercoat and a topcoat, in the preparation stage of the prepreg to be laminated and molded. There is a way. Conventionally, a base material is impregnated with an undercoat resin that is a mixture of a phenolic resin initial condensate and a melamine resin, and then dried.
Furthermore, a prepreg was produced by impregnating and drying an oil-modified phenol resin containing a flame retardant and a flame retardant resin as a top coat resin. Problems to be solved by the invention In the conventional method, flame retardance was ensured (94V-O)
Therefore, the undercoat resin is a mixed resin of a phenolic resin initial condensate and a melamine resin, and the topcoat resin is a flame retardant resin such as brominated epoxy resin and tetrabromobisphenol A or triphenyl phosphate. Since a large amount of bromine compound or phosphorus compound flame retardant was contained, the resulting laminate had poor interlayer adhesion when punched, poor heat resistance, and was more expensive. Therefore, an object of the present invention is to provide an inexpensive flame-retardant phenolic resin laminate that has good room-temperature punchability and heat resistance. Means for Solving the Problems The present invention has been made to achieve the above object, and consists of adding antimony pentoxide to a mixed resin of a phenolic resin initial condensate and a melamine resin in an amount of 5 to 50% by weight in terms of solid content. The first step is to impregnate the base material with an undercoat resin containing a sol and dry it.
The method is characterized in that a prepreg is created through a second step of impregnating and drying the base material that has undergone the first step with a top coat resin containing a weight percent of antimony pentoxide sol, and this is laminated and molded. Effects By having the above-mentioned characteristics, the present invention provides a flame-retardant phenolic resin laminate that requires high room-temperature punching workability, flame retardancy, heat resistance, and electrical properties. That is, in the conventional method, since there is a large amount of flame retardant in the top coat resin, the interlayer adhesion of the laminate is weak, which causes a decrease in room temperature punching workability and heat resistance. Therefore, by adding antimony pentoxide sol (water dispersion system, organic solvent dispersion system) to the undercoat resin and topcoat resin, which have a large flame retardant effect,
The use of bromine-based and phosphorus-based flame retardants in the top coat resin can be reduced, and the transparency of the laminate can also be maintained. However, if the antimony pentoxide sol is less than 5% by weight in the undercoat resin and less than 2% by weight in the topcoat resin, it will be sufficient to ensure flame retardancy (94V-O) and reduce the amount of bromine-based or phosphorus-based flame retardants. No effect was obtained. In addition, antimony pentoxide sol is in the undercoat resin.
If it exceeds 50% by weight, or exceeds 20% by weight in the top coat resin, the laminate becomes opaque and there are problems in terms of manufacturing and quality. Preferred amounts are 20% by weight for the undercoat resin and 5% by weight for the topcoat resin. Examples Next, examples of the present invention will be described together with comparative examples and conventional examples. () Production of phenolic resin initial condensate Nonylphenol 142g, 37% formalin 39
g, 86% paraform 51 g, trimethylamine 40
After reacting g at 80℃ for 90 minutes, phenol 429
Add 296 g of 86% paraform and heat at 75 to 65℃.
After reacting for an hour, 203 g of methanol was added and the mixture was cooled. The nonvolatile content of this resin was 50% by weight. () Production of tung oil-modified phenolic resin 366 g of cresol, 450 g of tung oil, and 0.47 g of paratoluenesulfonic acid were charged into a flask with a condenser and reacted at 80°C for 90 minutes with stirring, and then 307 g of phenol, 280 g of 86% paraform, and 25%
After adding 21g of ammonia water and reacting for 4 hours, dehydration was performed for about 1 hour under reduced pressure, and methanol
362 g and 356 g of toluene were added and cooled. The nonvolatile content of this resin was 50% by weight. () Manufacture of flame retardant resin 628 g of brominated epoxy resin and 23.2 g of diisopropyl phosphate were placed in a flask.
After reacting for 3 hours at ℃, 24.8g of diaminodiphenylmethane was added and reacted for 1 hour at 80℃, cooled, and 142g of triphenyl phosphate was added.
g and dissolve. () Manufacture of laminate board The resin obtained above was mixed with other components (melamine resin, antimony pentoxide sol) at the proportions (wt%) shown in Table 1 to prepare an undercoat resin and a topcoat resin. First, 11 mils kraft paper was impregnated with an undercoat resin and dried to obtain coated paper with a resin content of 10 to 15 percent by weight. Furthermore, this coated paper was impregnated with a top coat resin and dried to produce a prepreg having a resin content of 48 to 51% by weight. A predetermined number of sheets of this prepreg were laminated with copper foil on one surface of the prepreg, and molded for 60 minutes at 160° C. under heat and pressure of 100 kg/cm ² to obtain a single-sided copper-clad laminate with a thickness of 1.6 mm. Table 2 shows the characteristics test results of this copper-clad laminate.

【table】

[Table] Effects of the Invention As described above, according to the present invention, as is clear from Tables 1 and 2, while maintaining flame retardancy, it can be used together with bromine-based and phosphorus-based flame retardants in the top coat resin. It was also possible to reduce the amount of combustible resin and increase the amount of oil-modified phenolic resin, which made it possible to improve the in-air heat-resistant punching workability. Furthermore, by adding antimony pentoxide sol to the topcoat and undercoat resin, the amount of expensive bromine, phosphorus flame retardants, and flame retardant resins can be reduced, resulting in cost reductions, which is of great industrial value.

Claims (1)

[Claims] 1. The first step of impregnating the base material with an undercoating resin that is a mixture of a phenolic resin initial condensate and a melamine resin mixed with antimony pentoxide sol in an amount of 5 to 50% by weight in terms of solid content, and oil modification containing a flame-retardant resin. A prepreg is produced through the second step of impregnating and drying the base material that has undergone the first step with a top coat resin that is a mixture of phenolic resin and antimony pentoxide sol of 2 to 20% by weight in terms of solid content, and this prepreg is laminated and molded. A method for producing a flame-retardant phenolic resin laminate.