JPS6094351A - Manufacture of phenol resin laminated board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention belongs to the field of manufacturing technology for laminates, particularly phenolic resin laminates.

[Background technology]

An important characteristic of laminates for consumer use is punching workability. Due to the industry's needs for low-temperature punching and high-density punching, laminate resins are increasingly becoming plasticized.

Therefore, the phenolic resin in the phenolic laminate for low-temperature punching has a low glass transition point.

In addition, free phenol has a plasticizing effect,
Because it is difficult to remove, it was included in the laminate at about 1.0%. Furthermore, the resin paper (prepreg) contained 2.0% 4% free phenol.

As described above, the laminate for low-temperature punching that has been sufficiently OT-plasticized is too soft as a substrate.

Another problem was that the strength was weak when heated.

[Purpose of the invention]

The present invention aims to improve the strength of the laminate as a substrate, which is the problem described above, while maintaining low-temperature punching workability, and in particular, aims to improve the strength at high temperatures, that is, to improve the strength of the resin. do.

[Disclosure of the invention]

The usual method for manufacturing a phenolic resin laminate is to impregnate a paper base material (not limited thereto) with a phenolic resin face, heat and dry it, and then heat and pressure mold it. The present invention is to reduce the pressure in the process of heating and drying the prepreg impregnated with a phenolic resin in order to reduce the free phenol concentration in the laminate.

In the past, attempts have been made to reduce the pressure in the impregnation process in order to improve the impregnation of the resin into the base material, but this has not worked in the drying process.

This is because it has been determined that about 1% of free phenol in the laminated layer is not harmful, although it has a 90% effect.

The level of vacuum can be, but is not limited to, 500 m
About mHg to -750 mmHg is good, and the larger the reduced pressure, the more convenient it is.

By the above method, the free phenol content in the prepreg is set to 1.0 tF or more.

By using the above prepreg, even better results can be obtained if the free phenol content in the laminate is 0.3 or less. Note that if the free phenol content of the prepreg is 1.0 or less, in most cases it will be 0.3 or less in the laminate.

〔Effect of the invention〕

As described above, the viscoelastic spectra of the laminate resin in which the free-7 phenol was completely reduced and the laminate resin in which the free-7 phenol was not reduced are as shown in FIG. As can be seen from the following, it can be seen that the Young's modulus of the resin with reduced free phenol is improved. The effect is especially great when it's hot. However, there is no difference in glass transition temperature. Furthermore, there is no difference in the low-temperature punching processability of the laminates.

This will be explained below using Examples and Comparative Examples.

Example 1 Tung oil-modified phenolic resin was dissolved in methanol solvent.
Dilute it and make it into a festival. A piece of kraft paper with a thickness of 10 ml is soaked and impregnated into the fabric. -700mmHg immediately
Below, dry at a setting of 100°C to 160°C. The free phenol content of the resin-impregnated paper (prepreg) thus obtained was determined to be 0 when measured using a gas chromatograph.
．． It was 7%.

This prepreg was molded into an 1R layer by a conventional method to obtain a laminate with a thickness of 1.6 mm. 7 in the fuck board
When U-phenol was measured in the same manner as the prepreg, it was found to be 0.1%.

Example 2゜Similar to Example 1, but the level of vacuum was reduced to -600mm
It was set as Hg.

Free phenol was 0.9% in the prepreg and 0.3% in the laminate.

Comparative Example 1゜Same as Example 1, but with the dry workability of resin-impregnated paper,
The viscoelastic spectrum of the laminate resin was measured and was as shown in the table below.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the viscoelastic spectrum. patent applicant Matsushita Electric Works Co., Ltd. Representative Patent Attorney Toshimaru Takemoto (2 others)

Claims (1)

[Claims] (1) An impregnation step of impregnating a base material with a phenolic resin face to prepare a resin-impregnated base material, a drying step of heating and drying the resin-impregnated base material to prepare a prepreg, and heating and pressurizing the prepreg. A method for producing a phenolic resin laminate comprising a step of forming a phenolic resin laminate, the method comprising drying a resin-impregnated base material under reduced pressure. 2) The manufacturing method according to claim 1, wherein the prepreg is dried until the content of free phenol contained in the prepreg is 1.0% or less. (3) The manufacturing method according to claim 1, wherein drying is performed until the free phenol content in the laminate becomes 0.3% or less.