JPS6239170B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a paper-epoxy laminate that makes it possible to produce a paper-epoxy laminate with good low-temperature punching processability. Conventional paper epoxy laminates have passed NEMA FR-3, but they have problems with low-temperature punching. Therefore, in order to improve this point, a part of the epoxy resin was replaced with a flexible epoxy resin such as "Epicote 872" manufactured by Shell Chemical Co., Ltd., and cresyl diphenyl phosphate (hereinafter referred to as " Phosphate esters such as CDP (abbreviated as "CDP") are used. However, although this improves the low-temperature punching processability to some extent, it is still not fully satisfactory, and moreover, some problems arise in soldering heat resistance and electrical insulation. If a large amount of flexible epoxy resin is used, the flame retardance will be lowered, so it cannot be expected that the low-temperature punching processability will be further improved by using a large amount of flexible epoxy resin. In the above conventional example, the phosphoric acid ester used as a plasticizer has the effect of improving flame retardancy, and this prevents the flame retardance from decreasing due to the use of flexible epoxy resin. On the other hand, since this phosphoric ester has the property of lowering soldering heat resistance and insulation resistance, the conventional method produces the above results. In addition,
Some attempts have been made to improve the punching processability by adding an alkyd resin to the epoxy resin, but this method cannot be adopted because the flame retardance is significantly reduced. In view of these circumstances, in order to improve this point, the inventors made extensive research efforts and found that the problem of low-temperature punching processability was solved using the conventionally used 3,3'-diaminodiphenyl. It was determined that the cause of the problem was hardening agents such as sulfone (hereinafter abbreviated as "DDS"). That is, although conventional curing agents such as DDS do not reduce flame retardancy, they tend to produce cured products that are too hard and difficult to punch out at low temperatures. This invention was completed as a result of efforts to improve curing agents based on the above-mentioned findings.
The gist of the present invention is a method for producing a paper epoxy laminate, which is characterized in that a reaction product of maleic anhydride and tall oil fatty acid ester is used as a curing agent for the epoxy resin. Next, this will be explained in detail. In this invention, the tall oil fatty acid ester used as one of the raw materials for the curing agent of the epoxy resin is an ester of fatty acid obtained from sulfate pulp or soda pulp manufacturing waste and alcohol, especially polyhydric alcohol such as erythritol or glycerin. be. As the tall oil fatty acid ester, those having an acid value of 15 or less and an iodine value of 125 or more are usually used. However, it is not limited to this. As a reaction product of maleic anhydride and tall oil fatty acid ester, on a weight basis, maleic anhydride 1
Preferably, the reaction is carried out at a ratio of 3 to 4 parts of tall oil fatty acid. Further, as the reaction conditions, a reaction temperature of 120 to 150°C and a reaction time of 30 to 60 minutes are usually selected. However, the blending ratio of raw materials and reaction conditions are not limited to these. In this invention, a maleic anhydride-based curing agent is thus selected as the curing agent for the epoxy resin. Maleic anhydride itself is an excellent hardening agent in that it does not reduce flame retardancy, but like DDS, it tends to produce cured products that are too hard and have poor low-temperature punching properties. However, in the present invention, the above drawbacks are solved by combining this with tall oil fatty acid which has excellent flexibility. Furthermore, it is important that the tall oil fatty acid is combined with maleic anhydride in the form of a reactant rather than in the form of an additive. By this,
By taking advantage of the advantages of both, it is possible to achieve the object of the present invention, which is to improve low-temperature punching workability without any deterioration in flame retardancy, soldering heat resistance, or insulation resistance. In this invention, ordinary epoxy resins are used. Flexible epoxy resin is
Although its use is not avoided, it is not necessary to use it. The use of curing accelerators such as benzyldimethylamine, solvents such as methyl ethyl ketone, and flame retardants such as tetrabromobisphenol A is also the same as usual.Furthermore, the base material, its impregnation with varnish, drying method, and prepreg The lamination molding method is also a known method. Next, an embodiment of the present invention will be described together with a conventional example. First, Table 1 shows the chemical formulations.

[Table] In both Examples 1 and 2 and the conventional example, a 10 mil slinter paper with 5 wt % of antimony trioxide impregnated with 10 to 15 wt % of water-soluble resol resin and dried was used as the base material. Prepare a prepreg by impregnating it with 40 to 45 wt% of varnish having the composition listed in Table 1 and drying it. 8 sheets of this are stacked, copper foil with adhesive is placed on one side of the prepreg, and the prepreg is sandwiched between flat molds. 60 at 170℃ and 150Kg/ ^cm2
A laminate with a thickness of 1.6 mm was obtained by heating and press molding. The performance of the paper-epoxy laminates obtained in Examples 1 and 2 and the conventional example is as shown in Table 2. According to this, the laminates of Examples 1 and 2 are superior to the conventional example. , low-temperature punching processability has been improved,
In addition, the insulation resistance and soldering heat resistance are improved, and furthermore, it is found that there is no inferiority in flame retardancy.

【table】

【table】

Claims (1)

[Scope of Claims] 1. A method for producing a paper epoxy laminate, which comprises using a reaction product of maleic anhydride and tall oil fatty acid ester as a curing agent for the epoxy resin in producing the paper epoxy laminate. 2. The reaction product of claim 1, wherein the reaction product of maleic anhydride and tall oil fatty acid ester is a reaction product of 1 part maleic anhydride and 3 to 4 parts tall oil fatty acid ester on a weight basis. Method of manufacturing paper epoxy laminates.