JPS5952907B2 - Resin composition for flame-retardant laminates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition for laminates with excellent flame retardancy, and its purpose is to prevent the excellent low-temperature punching processability of the drying oil-modified phenolic resin from being impaired. To provide a resin composition capable of providing an inexpensive laminate that is flame retardant and has excellent heat resistance and electrical properties, and furthermore to provide a prepreg for the laminate that has improved storage stability. The object of the present invention is to provide a resin composition that can be used.

Conventionally, laminates using prepregs obtained by impregnating a cellulose base material with a drying oil-modified phenolic resin have been widely put to practical use because of their excellent low-temperature punching workability.

However, in recent years, with the expansion of demand fields, the demand for laminates with excellent low-temperature punching workability and flame retardancy has increased significantly. From this point of view, various studies have been made in an attempt to achieve the necessary flame retardancy by adding various flame retardants within a range that does not impair the low-temperature punching processability of the drying oil-modified phenolic resin. For example, (1) a method of manufacturing a laminate using a prepreg obtained by impregnating a base material with a resin composition in which a tung oil-modified phenol resin contains a halogenated phenol, such as tetrabromobisphenol A, as a flame retardant.

In this case, tetrabromobisphenol A is inexpensive, has a high bromine content, and exhibits an excellent flame retardant effect even when added in a relatively small amount. It is easy to cause dissociation, and there is a risk of discoloration and blistering of the 7-layer board.

In addition, the resulting laminate also has extremely low heat resistance and electrical properties, and furthermore, the relatively low molecular weight tetrabromobisphenol A exists in the laminate as a single molecule without bonding with other compounds. The optimal temperature range during punching was narrow, and the hardness of the laminate rapidly decreased when heated to a certain temperature, causing problems such as powder falling and whitening during punching. (2) A resin composition in which a flame-retardant epoxy resin, for example diglycidyl ether of tetrapromobisphenol A, is contained in a tung oil-modified phenolic resin is also known.

This resin composition is highly reactive, and the resulting laminate has excellent heat resistance and strength, but is extremely hard and has the required flame retardancy (UL).
-94V-(1) and punching workability (low temperature range 60-80
It is difficult to strike a balance between the following: (can be punched at ℃), and other additive flame-retardant plasticizers (organic phosphate esters) are required; in this case, heat resistance decreases and whitening is likely to occur during the punching process. There are drawbacks.

A further major drawback is that the prepreg obtained by impregnating a fiber base material with the resin composition has poor storage stability (pot life), making it difficult to market the laminate. Furthermore, in order to obtain the required flame retardancy, a considerable amount of flame retardant epoxy resin is required, which has the disadvantage of increasing costs. The present invention was made in order to improve such drawbacks, and a reaction mixture obtained by reacting a bisphenol A type epoxy resin compound having epoxy groups at both ends and a halogenated bisphenol A in advance, with the general formula R:H or CH3, A mixture obtained by adding 10 to 80% by weight of a monoglycidyl ether represented by C4H, At the very least, the aim is to obtain a resin composition for flame-retardant laminates.

Namely, halogenated bisphenol A is inexpensive and has a high Br content and has an excellent flame retardant effect, and bisphenol A has an epoxy group at both ends that provides a laminate with excellent heat resistance and electrical properties.
By reacting the type epoxy resin, the heat resistance, which is a drawback when the former is used alone, is improved, and the storage stability of the prepreg, which is a drawback when the latter is used alone, is improved.

However, even if the blending ratio of the halogenated bisphenol A and the bisphenol A portal epoxy resin is changed, or the blending ratio of the reaction mixture of the two and the drying oil-modified phenolic resin is changed, the desired flame retardance cannot be maintained. It is difficult to strike a balance between punching processability and storage stability of the prepreg. However, the desired flame retardancy and punching properties can only be achieved by incorporating a reaction mixture obtained by blending a monofunctional and zero-functional monoglycidyl ether into the reaction mixture and allowing it to participate in the reaction. It is possible to balance processability, heat resistance and storage stability of the prepreg. This is because the monoglycidyl ether reacts with the OH group generated by ring opening of the epoxy group in the reaction mixture of the halogenated bisphenol A and bisphenol A type epoxy resin and the terminal phenolic OH group, resulting in crosslinking. It can be assumed that this reduces the number of functional groups involved, prevents an increase in hardness when mixed with a dry oil-modified phenolic resin, and improves storage stability. In carrying out the present invention, bisphenol A type epoxy resin compounds having epoxy groups at both ends include diglycidyl ether of tetrapromobisphenol A, diglycidyl ether of bisphenol A, etc., and halogenated bisphenol A Examples include tetrapromobisphenol A, tripromobisphenol A1, dipromobisphenol A, etc., and tetrapromobisphenol A is particularly preferred from the viewpoint of flame retardancy.

Note that monofunctional halogenated phenols have poor heat resistance. Here, in the reaction between the bisphenol A type epoxy resin compound and the halogenated bisphenol A, it is preferable to use a tertiary amine as a catalyst in a range of 0.3 to 1 mol of the latter per 1 mol of the former. . If the amount of halogenated bisphenol A is less than 0.3 mole, the prepreg will not have sufficient storage stability, and in order to obtain the desired flame retardancy, it will be necessary to add a large amount of the reaction mixture to the drying oil-modified resin, resulting in high costs. become. On the other hand, if the amount exceeds 1 mole, a large amount of unreacted halogenated bisphenol A remains, and heat resistance becomes a problem. The monoglycidyl ether to be reacted with the reaction mixture obtained above is represented by the general formula R:H or 0H3,C4H9 ,
Dipromobutylphenyl monoglycidyl ether, monopromocresyl monoglycidyl ether, etc. can be used.

The amount of monoglycidyl ether added is preferably within the range of 10 to 80% by weight based on the reaction mixture of the bisphenol A type epoxy resin compound and halogenated bisphenol A (7) 1, and if it is less than 10% by weight, the prepreg Improvement in storage stability and good low-temperature punching processability of the laminate cannot be obtained, and if it exceeds 80% by weight, the heat resistance and moisture resistance of the laminate decrease. Furthermore, it is desirable to add the two monoglycidyl ethers at the time when the reaction between the bisphenol A type epoxy resin compound and the halogenated bisphenol A has reached equilibrium. The reaction of bisphenol A is accelerated, and only a low-molecular, flame-retardant resin composition is obtained, and a reaction mixture that provides a laminate with the required heat resistance and excellent electrical properties cannot be obtained. A drying oil-modified phenolic resin to which a reaction mixture containing a monoglycidyl ether is added is produced by reacting 10 to 50 parts by weight of a drying oil, such as tung oil, with 100 parts by weight of phenols under an acidic catalyst, and then reacting with a form under an amine catalyst. This is a known product obtained by reacting with teldehyde.

The amount of the reaction mixture added with the monoglycidyl ether added to the dry oil-modified phenolic resin can be increased or decreased depending on the required flame retardance (for example, 94-1.94V-0 specified by UL standards). However, in order to obtain a laminate with good low-temperature punching workability, electrical properties, and heat resistance, which is the objective of the present invention, the drying oil-modified phenolic resin should be
A range of 0 to 50% by weight is desirable; if it is less than 20% by weight, the required flame retardance is insufficient, and if it exceeds 50% by weight, the low temperature punching processability, which is a characteristic of drying oil modification, is reduced. When manufacturing a laminate using the resin composition of the present invention, antimony trioxide may be added as a flame retardant aid to a varnish in which the resin composition of the present invention is dissolved.

A fiber base material is impregnated with the varnish of the resin composition thus obtained and dried to form a prepreg, and then the required number of sheets of the prepreg are laminated and molded under heat and pressure. The present invention will be explained in more detail below using Examples.

Example 1 400 parts by weight of diglycidyl ether of tetrapromobisphenol A, which is a bisphenol A type epoxy resin compound having epoxy groups at both ends, 100 parts by weight of tetrapromobisphenol A, and toluene were added to make 60% by weight. After making a solution, 1 part by weight of benzyl dimethylamine was added to this solution and reacted at 100°C for 4 hours. Furthermore, 200 parts by weight of dibromocresyl monoglycidyl ether was added and reacted at 100°C for 2 hours ( Equilibrium concentration of epoxy groups), non-volatile content 60% by weight by adding toluene
A reaction mixture (A) was obtained.

On the other hand, tung oil-modified phenolic resin was prepared as follows.

Add 200 parts by weight of phenol, 300 parts by weight of cresol, 200 parts by weight of tung oil, and 5 parts by weight of a 10% aqueous solution of para-toluenesulfonic acid, react at 120°C for 3 hours, cool, and prepare 500 parts by weight of 37% formalin, 25% 15 parts of aqueous ammonia were added, and the mixture was reacted under reflux for 90 minutes.

Thereafter, it was dehydrated and a methanol-toluene (1:1) mixed solvent was added to prepare a varnish (B) with a non-volatile content of 60% by weight. Add varnish (B) to varnish (B) prepared in this way.
), the reaction mixture (4) has a solid content of 30
% by weight, and then 2% by weight of antimony trioxide was added as a flame retardant aid based on the total solid content of the varnish to prepare a varnish for the resin composition for impregnating a base material.

This varnish was impregnated into kraft paper having a thickness of 10 mils and dried to obtain a prepreg having a resin content of 50% by weight.

Nine sheets of the prepreg were layered and laminated (100 kg/Cn).
12 at 160° C. for 50 minutes) to obtain a laminate with a thickness of 1.6 m/m. Separately, a copper-clad laminate with 35μ copper foil attached was also obtained. Example 2 400 parts by weight of diglycidyl niter of tetrapromobisphenol A, 25 parts by weight of tetrapromobisphenol A
After adding 0 parts by weight and toluene to make a 60% by weight solution, 1.3 parts by weight of benzyldimethylamine was added to this solution, and the mixture was reacted at 100°C for 4 hours.

Furthermore, 100% dibromocresyl monoglycidyl ether
Parts by weight were added and reacted at 100° C. for 2 hours, and toluene was added to obtain a reaction mixture (C) with a nonvolatile content of 60% by weight. Varnish (B) was added to the varnish (B) prepared in Example 1. The reaction mixture (6) was blended so as to have a solid content of 20% by weight, and then antimony trioxide was added as a flame retardant aid at 2% by weight based on the total varnish solid content to impregnate the base material. A resin composition varnish was prepared. Thereafter, a laminated plate having a thickness of 1.6 m/m was obtained in the same manner as in Example 1. Comparative Example 1 Tetrapromobisphenol A was added to the varnish of Example 1 (B
) was added to varnish (B) in an amount of 25% by weight in terms of solid content (at 25% by weight, the required flame retardant V-0 was achieved), and Example 1
A laminate with a thickness of 1.6 m/m was obtained in the same manner as above.

Comparative Example 2 Addition of diglycidyl ether of tetrapromobisphenol A to varnish 8 of Example 1 at 40% by weight in terms of solid content based on varnish (B) (30% by weight does not provide the required flame retardancy) Then, in the same manner as in Example 1, a laminate with a thickness of 1.6 m/m was obtained.

Comparative Example 3 A reaction mixture obtained by reacting diglycidyl ether of tetrapromobisphenol A and tetrapromobisphenol A in the same manner as in Example 2 (dipromocresyl monoglycidyl ether was not reacted) was used as Varnish 8 of Example 1. To the varnish (3), 30% by weight was added in terms of solid content, and a laminate with a thickness of 1.6 m/m was obtained in the same manner as in Example 1.

Comparative Example 4 Dibromocresyl monoglycidyl ether was added to the varnish (B) of Example 1 in an amount of 40% by weight in terms of solid content (30% by weight does not provide the required flame retardancy)
Then, in the same manner as in Example 1, a laminate with a thickness of 1.6 m/m was obtained.

Characteristic tests were conducted on the laminates obtained in the above Examples and Comparative Examples, and the results shown in Table 1 were obtained.

As is clear from the results in Table 1, the laminate obtained by molding the prepreg in which the base material is impregnated with the varnish of the resin composition of the present invention has excellent heat resistance and electrical insulation properties, and also has excellent heat resistance and electrical insulation properties. Low temperature range (60-80℃) which is a characteristic of resin
Good punching workability was maintained, and because the amount of flame retardant present as a single molecule was reduced, whitening did not occur even in the temperature range of 80 to 100 degrees Celsius, and the amount of powder falling off was significantly reduced. .

In particular, the present invention improves the problem that when a flame-retardant epoxy resin compound is used in a drying oil-modified phenolic resin, the laminate becomes hard and the punching workability decreases, and the storage stability of the prepreg decreases. In addition, there is no need to use other additive-type flexible flame retardants (e.g. organic phosphate esters) or plasticizers, which may reduce heat resistance or cause white spots during punching. It is of great industrial value in that it can provide a highly practical flame-retardant laminate at a low cost.

Claims (1)

[Claims] 1. A reaction mixture of bisphenol A type epoxy resin compound having epoxy groups at both ends and halogenated bisphenol A has the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ R: H or CH_3, C_4H_0 X: Brn = 1 to 2 A monoglycidyl ether represented by 1 to 2 is added to the reaction mixture in an amount of 10 to 80% by weight, and a mixture obtained by reacting the mixture is added to a drying oil-modified phenolic resin in an amount of 20 to 50% by weight based on the resin. Resin composition for flame laminates. 2. The resin composition for a flame-retardant laminate according to claim 1, wherein the bisphenol A type epoxy resin compound having epoxy groups at both ends is diglycidyl ether of tetrabromobisphenol A. 3. The resin for flame-retardant laminates according to claim 1, wherein the amount of halogenated bisphenol A is 0.3 to 1 mole per mole of bisphenol A type epoxy resin compound having epoxy groups at both ends. Composition.