JPH0542453B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a method for producing a phenolic resin composition for lamination that imparts flame retardance without deteriorating various properties of the resin base. [Technical background of the invention and its problems] In recent years, paper phenol laminates used in electronic and electrical equipment have been developed from the viewpoints of process automation, energy saving, and dimensional accuracy of punched products in laminate processing.
There has been a demand for materials with excellent punching workability at room temperature or low temperatures near room temperature. On the other hand, members used in electronic and electrical equipment are also required to be flame retardant. Therefore, conventionally, in order to impart punching workability and flame retardancy to paper phenol laminates, various alkylphenols have been used in combination with phenol, or phenolic resins modified with drying oil, etc., have been used as a base. Added flame retardants. Methods for blending flame retardants can be roughly divided into two methods: methods using additive flame retardants in which a halogen or phosphorus compound is added to the resin, and methods using reactive flame retardants that react with the resin, such as halogenated epoxy compounds. In the former case, the flame retardant is mixed and added without reacting with other components, which has the disadvantage of reducing heat resistance, chemical resistance, etc. In the latter case, unreacted groups tend to remain, resulting in poor storage stability of the varnish or processed paper, and problems in manufacturing workability, such as difficulty in molding the mirror plate after molding. [Object of the Invention] The object of the present invention was to solve the above-mentioned drawbacks and problems. The present invention aims to provide a method for producing a flame-retardant phenolic resin composition for lamination, which has improved paper storage stability and workability. [Summary of the Invention] As a result of intensive research to achieve the above object, the present invention has been made based on the discovery that the above object can be achieved by using the method for producing a flame-retardant phenolic resin composition described below. It is. That is, the present invention provides (a) an addition reaction product of phenols and drying oil, and (b) a general formula (In the formula, R ¹ and R ² represent an alkyl group or a phenyl group, 1 + m + n = 3, n represents an integer of 1 or 2). This is a method for producing a flame-retardant phenolic resin composition, which is characterized by reacting the composition with another phenol and formaldehyde in the presence of a basic catalyst. The addition reaction product (a) used in the present invention is obtained by subjecting a phenol to an addition reaction with a drying oil. Examples of the phenols used here include phenol, cresol, xylenol, butylphenol, octylphenol, monobromophenol, dibromophenol, and the like, and these may be used alone or as a mixture. Next, examples of the drying oil include tung oil, dehydrated castor oil, linseed oil, and tall oil, which may be used alone or as a mixture of two or more. An acidic catalyst is used for the addition reaction, and an inorganic acid such as hydrochloric acid, sulfuric acid, or phosphoric acid, or an organic acid such as toluenesulfonic acid or xylenesulfonic acid is used. Examples of the phosphorus compound (b) used in the present invention include monochlorodiphenyl phosphate, dichloromonophenyl phosphate, monochlorodidecanyl phosphate, dichloromonomethyl phosphate, etc., which may be used alone or in combination of two or more. used as. The blending ratio of (a) addition reaction product and (b) phosphorus compound is
The residual rate of phenolic hydroxyl groups in the addition reaction product of (a) is
It is preferable to keep it in the range of 10 to 80%. If it is less than 10%, the reactivity with aldehydes will decrease when forming a resol, resulting in a decrease in various properties, which is undesirable, and if it exceeds 80%, it will not have any effect on flame retardancy and will have a plasticizing effect (poor punching workability). It is undesirable because there are few. Therefore, it is limited to the above range. (a) An addition reaction product and (b) a phosphorus compound are reacted to obtain phosphoric acid esters, and then a flame-retardant phenolic resin is produced by reacting with another phenol and formaldehyde to form a resol in the presence of a basic catalyst. Manufacture things. Examples of formaldehydes used here include formalin, paraformaldehyde, hexamethylenetetramine, etc., and these may be used alone or in combination of two or more. As the basic catalyst, amine catalysts such as ammonia, ethylenediamine, and trimethylamine, or metal hydroxides are used. [Effects of the Invention] According to the method for producing a flame-retardant phenolic resin composition of the present invention, it has excellent punching processability, heat resistance, and chemical resistance, and improves storage stability and workability of varnish and processed paper. A flame-retardant phenolic resin composition for lamination with improved properties is obtained, and is suitably used for circuit boards of consumer electronic devices. [Examples of the Invention] The present invention will be specifically described below with reference to Examples. Example 1 3000g of phenol, 3000g of tung oil, and 6g of p-toluenesulfonic acid were placed in a reaction vessel, stirred, and heated to 100°C.
After reacting at a temperature of 2 hours, unreacted phenol was removed to obtain an addition reaction product. This addition reactant
3970g and monochlorodiphenyl phosphate 1470g
After reacting with g at a temperature of 120° C. for 3 hours with stirring, the mixture was purified to obtain a phosphoric acid ester compound. Next, 5250g of phosphoric acid ester compound, phenol
After adding 2640 g, 3960 g of monobromophenol, 6960 g of 37% formaldehyde aqueous solution, and 75 g of monomethylamine and reacting under reflux for 2 hours,
Dehydration was performed under reduced pressure to remove unreacted materials, and a flame-retardant phenolic resin composition was produced. Add a mixed solvent of methanol and toluene to this composition to determine the resin solid content.
A 50% by weight varnish (A) was prepared. Comparative Example 1 Addition of phenol to 3970 g of the addition reaction product of Example 1
After adding 2640 g of monobromophenol, 3960 g of monobromophenol, 6940 g of 37% formaldehyde aqueous solution, and 75 g of monomethylamine and reacting under reflux for 2 hours,
Dehydration was carried out under reduced pressure and a mixed solvent of methanol and toluene was added to produce a phenolic resin varnish having a resin solid content of 50% by weight. Add 410 g of triphenyl phosphate to 3000 g of this phenolic resin varnish, and add methanol:
Varnish with a resin solid content of 50% by weight using a toluene mixed solvent.
(B) was prepared. Comparative Example 2 Phenol resin varnish 3000 produced in Comparative Example 1
g, add 410 g of tetrabromobisphenol A glycidyl ether, and add methanol:toluene mixed solvent to make a varnish with a resin solid content of 50% by weight.
(C) was prepared. The varnishes (A) to (C) prepared in Examples and Comparative Examples were impregnated onto cotton linter paper that had been undercoated with a water-soluble phenolic resin varnish, and dried to form a prepreg with a resin coverage of 50% by weight. Obtained. 8 sheets of prepreg are stacked together at a temperature of 165℃, 100Kg/cm ²
A laminate with a thickness of 1.6 mm was produced by heat-pressing molding for 60 minutes at a pressure of . This laminate was tested for insulation resistance, solvent resistance, in-air heat resistance, punching workability, and flame retardancy, and the results shown in Table 1 were obtained.

[Table] As is clear from Table 1, it was found that laminates using the varnish (A) according to the present invention had well-balanced properties.

Claims (1)

[Claims] 1 (a) an addition reaction product of phenols and drying oil; (b) general formula (In the formula, R ¹ and R ² represent an alkyl group or a phenyl group, 1 + m + n = 3, n represents an integer of 1 or 2). 1. A method for producing a flame-retardant phenolic resin composition, which comprises reacting with another phenol and formaldehyde in the presence of a basic catalyst. 2. A patent claim characterized in that the mixing ratio of the addition reaction product (a) and the phosphorus compound (b) is such that 10 to 80% of the phenolic hydroxyl groups in the addition reaction product remain after the phosphoric acid ester reaction. A method for producing a flame-retardant phenolic resin composition according to item 1.