JPS6023787B2 - Manufacturing method of resol type phenolic resin varnish - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a resol type phenolic resin varnish used for producing laminates and the like.

Generally, when producing a laminate such as a laminate, a base material such as paper or cloth is impregnated with a resol type phenolic resin varnish to create a prepreg, which is then heated and processed to form.

In this case, the resol type phenolic resin varnish was manufactured by dissolving the resol type phenolic resin in a solvent.
However, if a water-soluble resol type phenolic resin that can be directly impregnated into a base material without such a process can be synthesized, the manufacturing process of a laminate product can be shortened. In addition, due to recent demands for automation, it is required that manufactured laminates have high impact resistance. In response to these demands, a method for producing water-soluble resol-type phenolic resin and sol-type phenolic resin varnish (resol-type phenolic resin varnish for improving impact strength), which can produce laminates with high impact strength, has been proposed. The method for producing such a water-soluble resol type phenolic resin is as follows. That is, the formaldehyde concentration is 4
Prepare 5 to 70% by weight (hereinafter abbreviated as %) formaldehyde raw materials and phenol, mix these so that formaldehyde is 1.05 to 1.40 mol per 1 mol of phenol, and add pKalo as a catalyst. A water-soluble resol type phenol resin is produced by adding 0.01 mole of the above-mentioned tertiary amine, for example, triethylamine per mole of phenol, and reacting the formaldehyde raw material and phenol in this state. The hydrolyzed resol type phenolic resin produced in this manner has an average molecular weight of about 190 and can be directly impregnated into a substrate at room temperature. On the other hand, the method for producing a resol type phenolic resin varnish for improving impact strength is as follows. That is, formaldehyde raw materials and phenol with a formaldehyde concentration of 45 to 70% are prepared, and these are mixed so that the formaldehyde concentration is 1.05 to 1.40% per mole of phenol.
1 mole of phenol and aniline in an amount of 1.0 to 2.9 moles per mole of phenol.
Furthermore, as a catalyst, a tertiary amine with a pKalo or higher, such as triethylamine, is added at a rate of 0.01 per mole of phenol.
A resol-type phenolic resin (molecular weight 260-280) for improving impact strength is synthesized by blending in a molar ratio and reacting the three components in that state, and by adding a solvent to this, a resol for improving impact strength is synthesized. type phenolic resin varnish is produced. When a laminate is manufactured by impregnating a base material with the water-soluble resol type phenolic resin and the resol type phenolic resin varnish for improving impact strength obtained as described above, each desired purpose can be achieved. However, a problem arose in that smearing was more likely to occur during molding.In order to avoid this problem, the synthesis time for resol type phenolic resins for improving water lagoon properties and impact strength was extended, and the molecular weights were increased to 230 and 380, respectively. A laminate was produced by synthesizing a resin and impregnating a base material with this resin as it is or in the form of a varnish.
By using a resin with increased molecular weight in this way, it has become possible to prevent the occurrence of blurring during molding. However, because the gel time (curing time) of the resin synthesized in this way and the varnish using the same are short, the drying time when manufacturing laminates is extremely short, and continuous production using normal equipment is difficult. A new problem arose in that drying became difficult and drying workability deteriorated. In order to avoid this, when the drying temperature was lowered and the drying time was extended, the performance (heat resistance, electrical performance) of the laminate deteriorated because the volatile content in the base material did not evaporate. Therefore, an object of the present invention is to provide a method for producing a resol type phenolic resin varnish that does not cause such problems.

Next, this invention will be explained in detail.

As a result of repeated research on resol type phenolic resin varnishes, the inventors used a large molecular weight resol type phenolic resin, and converted this large molecular weight resol type phenolic resin into a glycol varnish having at least one ether bond. It has been found that when plasticized with a water-removalable polyester made of varnish, a varnish can be obtained that does not cause blurring during laminate molding and does not impair drying workability or the performance of the laminate. The resol-type phenolic resin with a large molecular weight used in this invention is a water-soluble resol-type phenolic resin with an average molecular weight of 220 to 250 for water-soluble resol-type phenolic resin varnish, and a resol-type phenolic resin for improving impact strength. For resin varnishes, resol type phenolic resins having an average molecular weight of 370 to 460 are used.

The reason why the average molecular weights of the resins used are limited in this way is as follows. In other words, if the water-bathable resol type phenolic resin has a molecular weight smaller than 220, it will not be possible to eliminate blurring during molding;
If it is larger than 50, the resin will be difficult to become water-soluble, and the gel time of the varnish will be short, resulting in poor drying workability. In addition, if the molecular weight of a resol type phenolic resin for improving impact strength is lower than 370, it will not be possible to eliminate scratches during molding, and if the molecular weight is higher than 460, it will be difficult to make into a varnish and the gel time will be short. This results in poor drying workability. Each of these sol-type phenolic resins is manufactured as follows.

That is, a water-soluble resol type phenolic resin having an average molecular weight of 220 to 250 is produced by reacting phenols and aldehydes under an alkaline catalyst, such as a tertiary amine catalyst having a pKalo or higher. Average molecular weight 37
Resol type phenolic resin for improving impact strength of 0 to 460 contains aniline in addition to phenol and aldehyde (1.0 to 2.9 molar ratio per mole of charged phenol)
It is produced by adding and reacting under an alkaline catalyst, such as an amine catalyst. A varnish is produced by adding and mixing a water-soluble polyester (hereinafter referred to as water-dropable polyester) made of a glycol having at least one ether bond to the resol type phenolic resin thus produced. In this case, the water-soluble polyester used can be synthesized from, for example, diethylene glycol and adipic acid. Although the molecular weight of this material is not particularly limited, it is preferable to use one having a molecular weight of 500 to 2,000. And the amount added is
5-30P for water-soluble resol type phenolic resin
It is preferable to select 5 to 3 bases per 10 parts of HR, ie, resin solids. In this range, the varnish exhibits water-removal properties. If the amount added is outside the lower limit, the gel time will be short, resulting in poor drying workability; if it is outside the upper limit, the gel time will be long, but the insulation resistance of the laminate will be poor. On the other hand, the amount of water-soluble polyester added to the resol type phenol resin for improving impact strength is preferably selected to be 5 to 3 tsubo HR. If the amount added is out of this range, the above-mentioned problems will occur. Since the varnish obtained in this way is made by plasticizing a resin with a large molecular weight with water-soluble polyester, it does not cause blurring during the production of laminates, and does not impair drying workability or the performance of laminates. Nor.

That is, since the varnish of the present invention contains a resin that has a large molecular weight and is difficult to cause scratches, the occurrence of scratches during molding is suppressed. In addition, since such resin is plasticized with water-soluble polyester, the gel time of the varnish is increased and it can be dried in the usual manner using ordinary drying equipment. As a result, drying efficiency deteriorates,
The performance of the laminated product is not impaired. In addition, laminated products obtained using varnish containing resin for improving impact strength,
Extremely high impact strength. Next, examples will be described. Examples 1 and 2 and Comparative Examples 1 and 2 (water-soluble varnish) Phenol 940 (10 tamol), 55
% high concentration formalin 655 mol (129 mol) and triethylamine 10.1 mol (0.1 mol) were placed in a flask, and after attaching a base pestle, a thermometer, and a reflux condenser, the mixture was heated under a syringe. It took 30 minutes to boil.

Thereafter, the reaction was continued for about 75 minutes, and then cooled to complete the reaction. The obtained resin was a clear liquid with an average molecular weight of 241 and a solid content of 64%. A water-soluble polyester (molecular weight 1000) was blended with the obtained resin as shown in Table 1 to obtain a varnish for impregnation. Thereafter, impregnation, drying, and lamination molding were performed according to conventional methods to obtain a laminate. Comparative Example 3 In Example 1, the average molecular weight was increased to 29 by extending the reaction time.
Resin No. 5 was synthesized.

Other than that, a varnish was made in the same manner as in Example 1, and a laminate was obtained using the varnish. Comparative Example 4 In Example 1, the average molecular weight was reduced to 19 by shortening the reaction time.
0 resin was synthesized.

Then, this material was directly impregnated into the base material. A laminate was obtained in the same manner as in Example 1 except for the above. The molecular weight, amount of water-soluble polyester added, gel time, moldability, drying workability, and insulation resistance of the laminates of the resins obtained in the above Examples and Comparative Examples are summarized in Table 1.

Table 1 Examples 3 and 4 and Comparative Examples 5 and 6 (varnish for improving impact resistance strength) Aniline 195 was further added to the raw material formulation of Example 1, and the same procedure as in Example 1 was carried out. react,
A resin with an average molecular weight of 378 was synthesized.

A water-repellent polyester (molecular weight 1000) was blended with this resin as shown in Table 2 to obtain an impregnating varnish. and,
A laminate was manufactured using this varnish. Comparative Example 7 In Example 3, the average molecular weight was increased to 47 by extending the reaction time.
0 resin was synthesized.

Other than that, a varnish was made in the same manner as in Example 3, and a laminate was manufactured using the varnish. Comparative Example 8 In Example 3, the average molecular weight was reduced to 27 by shortening the reaction time.
0 resin was synthesized.

Then, a varnish was made by adding a solvent to this, and a laminate was manufactured using this.The molecular weight of the resin obtained in the above examples and comparative examples, the amount of water-dropping polyester added, gel time, moldability, and drying work The properties and insulation resistance of the laminate are summarized in Table 2.

Table 2

Claims (1)

[Scope of Claims] 1. A resol type phenol resin having an average molecular weight of 220 to 250 is synthesized by reacting phenols and aldehydes under an alkaline catalyst, and to this, at least 1
1. A method for producing a resol type phenolic resin varnish, which comprises adding and mixing 5 to 30 PHR of a water-soluble polyester using a glycol having two ether bonds. 2. A resol type phenolic resin with an average molecular weight of 370 to 460 is synthesized by adding a small amount of aniline to phenols and aldehydes and reacting them under an alkaline catalyst, and then using a glycol having at least one ether bond. 5-35 water-soluble polyester
A method for producing a resol type phenolic resin varnish, which is characterized by adding and mixing PHR.