JPH0120170B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a flame-retardant cyanate ester curable resin using a nuclear halogenated aromatic polycarbonate oligomer. More specifically, polyfunctional cyanate esters, or polyfunctional cyanate esters and polyfunctional maleimides are
It is characterized by adding a nuclear halogenated aromatic polycarbonate oligomer at the beginning of the reaction or when the viscosity is 10 poise or less when reacting under melting and stirring at ~100°C for 0.5 to 20 hours to oligomerize. This invention relates to a method for producing a solvent-free flame-retardant cyanate ester curable resin.

Nuclear halogenated aromatic polycarbonate oligomers are excellent and useful flame retardants for cyanate ester resins, but are usually homogeneously mixed in a state dissolved in a solvent such as methyl ethyl ketone. In order to uniformly mix the two without using a third component such as a solvent, it is necessary to mix a cyanate ester resin with a high melt viscosity with a nuclear halogenated aromatic polycarbonate oligomer with a high melting point. Requires kneading. In these cases, the polymerization reaction progresses when heated, and this is not preferable in terms of saving labor and resources.

The present inventors have completed the present invention as a result of intensive study on a method for obtaining a flame-retardant cyanate ester resin that can be easily and uniformly mixed without using a third component such as a solvent. Ta.

In the present invention, the addition amount range of polyfunctional cyanate ester A, polyfunctional maleimide B, and nuclear halogenated polycarbonate oligomer is A:B:C=20-100:0-80:2-50. .

In the present invention, the nuclear halogenated aromatic polycarbonate oligomer is used at the initial stage of the reaction to the viscosity when polyfunctional cyanate esters or polyfunctional cyanate esters and polyfunctional maleimides are heated to react and oligomerize. is below 10 poise. The viscosity of the resin reaction solution before adding the nuclear halogenated aromatic polycarbonate oligomer is 10
If the poise exceeds 100 poise, in particular, it becomes difficult to form a homogeneous system in which the nuclear halogenated aromatic polycarbonate oligomer is dissolved.

In the present invention, polyfunctional cyanate esters refer to the following general formula R ¹ -(O-C≡N)m...(1) (m in the formula is an integer of 2 or more and usually 5 or less.
R ¹ is an aromatic organic group, and the cyanato group is bonded to the aromatic ring of the organic group R ¹ . Specific examples include 1,3- or 1,4-dicyanatobenzene,
1,3,5-tricyanatobenzene, 1,3
-, 1,4-, 1,6-, 1,8-, 2,6- or 2,7-dicyanatonaphthalene, 1,3,
6-tricyanatonaphthalene, 4,4'-dicyanatobiphenyl, bis(4-cyanatophenyl)methane, 2,2-bis(4-cyanatophenyl)propane, bis(4-cyanatophenyl) enyl) ether, bis(4-cyanatophenyl)
Thioether, bis(4-cyanatophenyl)
These include sulfones, and cyanate esters obtained by the reaction of novolaks with cyanogen halides. In addition to these, Tokuko Sho 41-1928, Tokuko Sho 44-
Cyanic acid esters described in Japanese Patent Publication No. 4791, Japanese Patent Publication No. 45-11712, Japanese Patent Publication No. 46-41112, and Japanese Unexamined Patent Publication No. 51-63149 may also be used.

In the present invention, polyfunctional maleimides are defined by the following general formula: (In the formula, R ² is an aromatic or alicyclic organic group with a valence of 2 or more and usually 5 or less, X ¹ and X ² are hydrogen or an alkyl group, and n is a valence of 2 or more and usually 5 or less. is an integer). The maleimide represented by the above formula is prepared by reacting maleic anhydride with a divalent or higher polyamine to prepare maleamic acid.
It can then be produced by a method known per se in which maleamic acid is cyclodehydrated. It is preferable that the polyamines used are aromatic amines in terms of the heat resistance of the final resin, but if flexibility and flexibility of the resin are desired, alicyclic amines may be used alone or in combination. good. Furthermore, it is particularly desirable that the polyvalent amines be primary amines in terms of reactivity, but secondary amines can also be used.

In the present invention, the nuclear halogenated aromatic polycarbonate oligomer has the following general formula as a repeating unit: (R ³ in the formula is a divalent lower alkyl group or a phenyl-substituted lower alkyl group, and Y ¹ and Y ² are
Cl or Br, q ₁ and q ₂ are integers of 1 to 4, p
is an integer between 2 and 30. ), and those whose terminals are stabilized (usually treated with phenols such as monovalent phenol, p-tert-butylphenol, and tribromophenol) are preferred; It may be an untreated product.
Further, the degree of polymerization n is preferably 2-10, more preferably 2-6.

Since the resin obtained by the production method of the present invention does not contain components such as solvents, it can be used for applications such as molding materials and powder coatings, and it can be used for applications such as molding materials and powder coatings. It can also be suitably used as a solvent varnish.

The present invention will be explained in more detail below using Examples and Comparative Examples.

Example 1 A cylindrical reaction pot with a diameter of 200 mm and a height of 200 mm
A stirrer equipped with a 40 mm turbine spring (4 springs) was set up, and 2550 g of bis(4-cyanatophenyl) ether was charged while heating and melting it. During the experiment, the stirring rotation speed was 300 rpm. After setting the liquid temperature to 140°C (0.2 poise), the terminal was treated with 2,4,6-tribromophenol to obtain 2,2-(4
-Hydroxy-3,5-dibromophenyl-4'-
Polycarbonate oligomer of hydroxy-3′-bromophenyl)propane (average degree of polymerization 4.2) 450
When g was added, the entire amount dissolved within 1 minute to form a pale yellow, transparent reaction liquid.

Furthermore, after reacting for 300 minutes at a reaction temperature of 150°C,
Upon cooling, a pale yellow, transparent, uniform solid resin was obtained.

Example 2 Using the same reaction apparatus as in Example 1, 2100 g of 2,2-bis(4-cyanatophenyl)propane and 300 g of bis(4-maleimidophenyl)methane were melted by heating and reacted at 150°C for 60 minutes. (1.2 poise), the terminally treated 2,2-
When 600 g of polycarbonate oligomer of bis(4-hydroxy-3,5-dibromophenyl)propane (average degree of polymerization 3.5) was added, it dissolved within 3 minutes to form a brown, transparent reaction liquid.

After further reacting for 180 minutes at a reaction temperature of 150°C, the mixture was taken out into a vat and cooled to obtain a brown, transparent, uniform solid resin.

Comparative Example 1 Using the same reaction apparatus as in Example 1, 2100 g of 2,2-bis(4-cyanatophenyl)propane and 300 g of bis(4-maleimidophenyl)methane were melted by heating and reacted at 150°C for 300 minutes. At the time point (310 poise), the terminal was treated with phenol 2,
When 600 g of a polycarbonate oligomer of 2-bis(4-hydroxy-3,5-dibromophenyl)propane (average degree of polymerization 3.5) was added, the polycarbonate oligomer floated on the surface and did not dissolve. When stronger stirring was performed, the polycarbonate oligomer was dispersed, but a uniformly dissolved composition was not obtained.

Comparative Example 2 In Comparative Example 1, instead of the polycarbonate oligomer of 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, an epoxy equivalent of 279 was obtained by reacting brominated phenol novolac with epichlorohydrin. , bromine content 35~
The same procedure was followed except that 37% epoxy resin was used. As a result, the epoxy resin was uniformly dissolved and mixed while melting, and even after cooling and solidifying, it became a transparent and uniform solid resin.

Claims (1)

[Claims] 1 Polyfunctional cyanate esters or polyfunctional cyanate esters and polyfunctional maleimides at 80%
It is characterized by adding a nuclear halogenated aromatic polycarbonate oligomer at the beginning of the reaction or when the viscosity is 10 poise or less when reacting under melting and stirring at ~100°C for 0.5 to 20 hours to oligomerize. A method for producing a solvent-free flame-retardant cyanate ester curable resin.