JPS5879060A - Flame-retardant epoxy resin varnish - Google Patents

Abstract

PURPOSE:The titled varnish that is prepared by adding a powder of dicyandiamide to a solution containing an epoxy resin, a compound bearing phenolic hydroxyls and a bromine-containing compound, thus showing a long pot life, even when stood at higher temperatures, and high dispersion stability and giving uniformly cured products. CONSTITUTION:(A) An epoxy resin containing bromine such as bisphenol-A is mixed with (B) a compound containing phenolic hydroxyls such as catechol, for example, at a ratio of 0.05-5 phenolic groups to one epoxy group in component A, further (C) a solvent such as acetone is added to give a mixed solution of 1.33-1.52 specific gravity at 25 deg.C. Then, (D) a powder of dicyandiamide of less than 50mum average particle size is mixed with the solution to give the objective varnish. EFFECT:The resultant varnish shows good electrical properties, high thermal charcteristics and high chemical resistance. USE:Talc or quartz is added thereto and used in laminating or coating.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated,
This relates to epoxy resin varnish suitable for painting, etc. More specifically, it is a high-solid flame-retardant epoxy that has a relatively short pot life even at high temperatures and has good dispersion stability to give a uniformly cured product. Regarding resin varnishes, epoxy resins are widely used in the electrical and electronic fields due to their excellent mechanical properties, electrical properties, thermal properties, chemical resistance, and adhesive properties. In the electrical and electronic fields, in recent years, varnishes have been made flame retardant to prevent fires during use, and solvent-free varnishes have been developed to improve working environments and solve pollution problems, as well as to save resources. and increasing solidity are major issues.

The present invention provides a non-inlid type flame-retardant epoxy resin face that solves the above problems.

That is, according to the present invention, the epoxy resin (4) and the compound (B
) in a common solvent (C) K, which contains a bromine-containing compound in either one of the epoxy 11 fat (4) and the compound (B) having a phenolic hydroxyl group. , and the phenolic hydroxyl group is 005 to 0.5 per epoxy group of the epoxy resin.
The compound (B) is blended so that the percentage of the common solvent (C) is added, and the ratio i at 25° C. is 1.
This flame-retardant epoxy resin face is characterized by mixing dicyandiamide powder with an average particle size of 50 μm or less in a dispersed state into a mixed solution having a VC in the range of 33 to 1.52.

The epoxy as'# used in the present invention is 2,2-bis(4-hydroxyphenyl)propane (represented by JJ under Mesphenol A), bis(4-hydroxyphenyl)methane (represented by Bisphenol F under C) diglycidyl ethers of bis(4-hydroxyphenyl)arone chlorides, polyglycidyl ethers of polyhydric phenols such as phenol novolak and cresol novolak, polyglycidyl ethers of aliphatic polyhydroxy compounds such as ethylene glycol and polyethylene glycol, etc. These are diethyl ethers and mixtures thereof.

In addition, bromine-containing epoxy resins include epoxy resins that are liquid at room temperature.
Bisphenol A1 Nohis(4-hydroxyphenyl) alkanes such as bisphenol F, bromine such as 2,2-bis(4-hydroquine-3-s-cyfuromophenyl)propane (hereinafter referred to as tetrabromobisphenol A) Reacting with epibromohydrin, epichlorohydrin, and other epino-rohydrins with l&substituted bis(4-hydroxyphenyl) alkanes and vr-damaged epoxy resins and brominated bis(4-hydroxyphenyl) alkanes. diglycidyl ethers obtained by reacting with evino lohydrin; diglycidyl obtained by reacting diglycidyl ethers of bis(4-hydroxyphenyl) plucans with brominated bis(4-hydroxyphenyl) alkanes; Ether etc.

It is also possible to use reactive diluents containing at least one epoxy group, such as butyl glycidyl ether, dibromucresyl glycidyl ether, and the like.

Examples of compounds having at least two phenolic hydroxyl groups in the molecule include dihydric phenols such as catechol, resorcinol, bisphenol A1 bisphenol F, te, and trabromobisphenol A, pyrogallol, phenol novolac T14 compound, cresol novolac resin, These are polyhydric phenols such as polyparavinylphenol and bromine-substituted polyparavinylphenol, and mixtures thereof.

The blending ratio of the mixture of epoxy resin and compound that supports phenolic hydroxyl groups is 1 epoxy group of epoxy resin.
It is preferable to mix the compound having a phenolic hydroxyl group so that the number of phenolic hydroxyl groups is in the range of 0.05 to 0.5.

When the number of phenolic hydroxyl groups is less than 0.05, curing stray electricity is slow, and the effect of improving the performance of the cured product, special VC bending force, water resistance, etc., which is improved by adding the compound, is almost negligible. (, Mat(, phenolic hydroxyl group is 0,
If the number exceeds 5, curing progresses before the powdered dicyandiamide is completely dissolved, and dicyandiamide remains unreacted in the cured product, which may affect the durability of the cured product, especially its chemical resistance and heat resistance. Therefore, it is necessary to blend the number of phenolic hydroxyl groups to one epoxy group in the range of 0.05 to 0.5.

Common solvents for both include acetone, methyl ethyl ketone, toluene, xylene, and the like.

In addition, when determining the composition, the tA should be adjusted so that the specific gravity of the mixed solution at 25°C is in the range of 1.33 to 1.52 in order to improve the dispersion stability of dicyandiamide. For this purpose, a bromine-containing epoxy resin or a bromine-containing compound having a phenolic hydroxyl group is used in a mixture with a bromine content of about 16 to 32
It is preferable to mix them so that they are evenly mixed, and furthermore, the amount of the common solvent for both is 20 parts by weight or less based on 100 parts by weight of the mixture. The bromine content of the mixture is 16-3211t%.
By adjusting this, it is possible to simultaneously impart aS properties to the composition.

The dicyandiamide used in the present invention has an average particle size of 50 μm or less obtained by finely pulverizing it with a jet pulverizer (manufactured by Nippon Pneumatic ■), for example.

The average particle size is set to 50 μm or less because the average particle size is 50 μm or less.
If it exceeds m, even if the specific gravity of the mixture is in the range of 1.33 to 1.52, if the viscosity V of the mixture decreases due to heating etc., precipitation and floating of dicyandiamide will be observed, resulting in uneven curing. This is because the properties of the cured product are inferior. In addition, since powdered dicyandiamide completely dissolves and reacts before curing is completed, it is more preferable that the particle size of dicyandiamide is smaller, and from this point of view, it is important that the average particle size of dicyandiamide is 50 μm or less. It is.

The epoxy resin varnish of the present invention is produced by mixing and dissolving a mixture of an epoxy resin, a compound having a phenolic hydroxyl group, and a common solvent for both in rIAwI at room temperature to 200°C to obtain a mixed solution. It is produced by adding finely pulverized dicyandiamide to the mixture and kneading it uniformly using a three-roll roll or the like. Since the phenolic hydroxyl group slightly reacts with the epoxy group during production, it is preferable to mix and dissolve at the lowest temperature possible. The amount of dicyandiamide to be used is preferably 1 to 5 parts by weight per 100 parts by weight of the epoxy resin and the compound having a phenolic hydroxyl group.

Furthermore, if it is necessary to speed up the curing period of one varnish, a curing accelerator may be used in combination. As a curing accelerator,
For example, aliphatic tertiary amines with an aromatic ring such as benzyldimethylamine, unsaturated ring tertiary amines such as pyridine, urea compounds such as 3(3-chlorophenyl)-1,1-dimethylurea, Boron-1 amine complexes, imidazoles, etc. can be used. Also, it is possible to use the amount of #composition! Since the time is short, it is necessary to determine the amount by pouring a sufficient amount, but usually, 1 part or less is used for the epoxy resin.

The epoxy resin varnish of the present invention obtained in this way has good storage stability at low temperatures because dicyandiamide before latent curing is dispersed in powder form, and it also has phenolic hydroxyl groups. 100℃ to
By heating to the above temperature, the IIC curing reaction proceeds rapidly. In addition, the average particle size of dicyandiamide is set to 50 μm or less, and the specific gravity of the epoxy resin mixture at 25°C is set in the range of 1.33 to 1.52 Klt[J! +-, By making the specific gravity close to that of dicyandiamide, the dispersion stability is good not only at room temperature but also when the viscosity 1 of the varnish is lowered by heating at 40 to 80°C x 7FOa.
Talc is added to the epoxy resin varnish of the present invention as required.
It can be used for lamination, painting, etc. by adding various additives such as inorganic fillers such as quartz powder, pigments, and dyes.

Even in these applications, by using dicyandiamide with an average particle size of 50 μm or less, the light penetrates even into the minute parts of the base material and curing progresses uniformly, so the resulting cured product has good mechanical properties. , excellent electrical properties, thermal properties, chemical resistance, etc.

Example 1 Bisphenol A34f, tetrabromobisphenol A 109'? and epichlorohydrin 260) 1
Mix and dissolve in a separable flask, add sodium hydroxide as a reaction catalyst, react at 80°C for about 4 hours, remove excess epichlorohydrin in vacuum, and wash the produced sodium chloride with water to release bromine. Lid 2.4 weights
, an epoxy resin having an epoxy equivalent of 248 was obtained. Transfer 200 g of the obtained epoxy resin to another separable flask, and add 45% of bisphenol A. , methyl ethyl ketone (15) was added, and the mixture was stirred and mixed at 100° C. for about 30 minutes to obtain a uniform mixed solution. The specific gravity of this liquid-resistant mixture at 25° C. was 1.33, the viscosity # at 35° C. was 15 voids, and the bromine content was 19.5% by weight relative to the solid content.

To the obtained mixed solution, 87% of dicyandiamide powder with an average particle size of 15 μm and 0% of benzyldimethylamine were added.
．． 57 processing and kneading with three rolls to obtain an epoxy resin varnish.

The resulting nine varnish straw ta-cure was heated to 25°C at 180°C.
It was 0 seconds. Also, the viscosity 1 of the varnish at 60°C is 1
．． Viscosity fFi after 5 hours at this temperature with 2 voices
ts poise, but no precipitation of dicyandiamide powder was observed.

Example 2 Aguaax (manufactured by Asahi Kasei Kogyo ■, bisphenol A
Diglycidyl ether, epoxy equivalent weight 190) 4jOP
, DIR542 (manufactured by Dauke Zecal, tetrabromobisphenol A diglycidyl ether, epoxy equivalent: 345
, bromine content 48% by weight) 320 t s Pisphenolum 1209, phenol novolak resin (average molecular weight 35 tO) 2G? and BROC as a reactive diluent
■ (manufactured by Nippon Kayaku ■, dibromucresyl glycidyl ether) a o Ps acetone 25? were placed in a separable flask and stirred and mixed at 60° C. for about 30 minutes to obtain a uniform mixed solution. The specific gravity of this mixed solution at 25°C is 1.
No. 33, the viscosity at 35° C. was 7 voids, and the bromine content was 18% by weight based on the solid content. To the resulting mixed solution, add dicyandiamide powder with an average particle size of 15 μm.
4 G? ,3 (3-1rypy)xnyl)'=1-1
-Dimethylurea was added to the mixture and kneaded using three rolls to obtain an epoxy resin IIh varnish.

Stroke cure of the obtained varnish H116 at 80℃
It was 0 seconds. Also, the viscosity tf of the varnish at 45°C
3 voids and left at this temperature for 5 hours, the viscosity did not change and no precipitation of dicyandiamide powder was observed. Example 3 AER331 (manufactured by Asahi Kasei Corporation, bisphenol A diglycidyl ether, epoxy equivalent 190) 650 ? and tetrabromobisphenol A350P, methyl ethyl ketone 50F were placed in a separable flask, and 100
The mixture was stirred and mixed at ℃ for about 30 minutes to obtain a uniform mixed solution. The specific gravity of this mixed solution at 25° C. was 1.35, the viscosity at 35° C. was 20 voids, and the bromine content was 20% by weight based on the solid content. 17 for the obtained mixed solution
, 3071 dicyandiamide powder with an average particle size of 15 p@
2 tons of benzyl dimethyl chlorine was added and kneaded using three rolls to obtain an epoxy resin varnish.

Stroke cure a of the resulting varnish, 30 at 180°C
It was 0 seconds. Also, the viscosity of varnish at 60°C is 1
．． The viscosity is 2 after leaving it for 5 hours at 5 voise.
At 5 poise, no precipitation of dicyandiamide powder was observed.

Example 4 Methyl ethyl ketone (TO) was further added to the mixed solution obtained in Example 1.3 and the mixed solution obtained in Example 3 as a comparative example to obtain a specific gravity of 1.28 at 25°C. For the mixed solution of Nire et al., the average particle size was 15Fm.
s45#ttte75μm dicyandiamide powder
The amount of sedimentation of dicyandiamide powder after adding parts by weight of varnish to a sedimentation tube and leaving it at 60°C for 10 hours is shown in Table-IK.
show.

Table 1 Sedimentation amount of dicyandiamide (10 hours 1t66℃
,) Patent applicant Asahi Kasei Industries, Ltd.

Claims (1)

[Scope of Claims] 1. A mixed solution of an epoxy resin and a compound having at least two phenolic hydroxyl groups in its molecule dissolved in a common solvent (C) K for both, which comprises an epoxy resin 1f.
One or both of lir (A) and the compound (B) having a phenolic hydroxyl group contains a bromine-containing compound, and the number of phenolic hydroxyl groups is 0.0% per 1 epoxy group of the epoxy resin (4). The specific gravity at 25°C is 1.33 to 1 by blending KM compound 0) so that the number is in the range of 05-0.5 and further adding 1 common solubilizer C).
．． For mixed solutions in the range of 52, the average particle size is 50 μm.
Flame-retardant epoxy resin varnish 2 characterized by mixing the following dicyandiamide powder in a dispersed state. 5 parts by weight of the flame-retardant epoxy resin varnish 3 according to claim 1, wherein the mixed solution contains an epoxy resin (A) and a compound having a phenolic water group). The flame-retardant epoxy resin varnish according to claim 1, wherein the common solvent (C) is 20 parts by weight or less based on 100 parts by weight of the mixture.