JPH01259017A - Production of flame-retarded and oil-modified phenolic resin - Google Patents

Abstract

PURPOSE:To obtain the subject resin useful for production of electric insulation material having excellent non-flammability, punching processability and also electric characteristics by reacting drying oil and phenols in the presence of phosphoric acids and adding ammonia and amines. CONSTITUTION:In the presence of (A) phosphoric acids as acid catalysts, (B) a drying oil is reacted with (C) phenols and made to attain to suitable degree of conversion, then (D) an ammonia as neutralizing agent is added to component A and transferred to ammonium phosphate and simultaneously (E) amines as base catalysts are added and aldehydes are reacted to afford the aimed resin. Preferably, component A is orthophosphoric acid and the adding amount is 1-5wt.% to the total amount of component B and component C.

Description

Detailed Description of the Invention (a) Object of the Invention [Field of Industrial Application] The present invention relates to a method for producing a flame-retardant oil-modified phenolic resin used in producing electrically insulating materials.

[Background Art] In recent years, in the electronic equipment industry, high-density wiring, high-density component mounting, and automation of component mounting have been rapidly progressing by converting electronic components into chips. For this reason, printed wiring boards used in electronic devices are required to have high electrical properties and high dimensional accuracy, and in particular, flame retardancy has become an essential condition.

In order to meet the demand for finished dimensional accuracy, we adopted a low-temperature punching method to form mounting holes for mounted components, so we modified the phenolic resin used as an insulating material for printed circuit boards with a drying oil such as tung oil. Measures plasticity.

In response to the demand for flame retardancy, drying oil and phenols are reacted in the presence of an acidic catalyst such as mineral acid or organic acid, then aldehydes are added and reacted in the presence of a basic catalyst to produce an oil-modified phenolic resin. There are flame-retardant oil-modified phenolic resins for laminates that have been made flame-retardant by adding inorganic compounds such as phosphorus compounds, halogen compounds, nitrogen compounds, and aluminum hydroxide as flame retardants, either singly or in combination. .

[Problems to be Solved by the Invention] It is necessary to use an oil-soluble flame retardant in such a flame retardant oil-modified phenol resin for laminates in order to uniformly disperse the flame retardant. For example, in the case of a phosphorus compound having a large flame retardant effect, it is used in the form of an oil-soluble phosphoric ester such as triphenyl phosphate or cresyl diphenyl phosphate. These phosphoric acid esters have a low phosphorus content and must be added in large amounts to obtain the desired flame retardant effect. The crosslinking density decreases during the punching process for mounting component mounting holes in copper-clad laminates for printed circuits.
This results in drawbacks such as ri peeling and whitening around the processed holes, and also results in a reduction in the electrical properties, solvent resistance, etc. of the laminate.

This invention has been made in view of the above points, and aims to achieve high electrical characteristics, high dimensional accuracy,
It was developed to meet various requirements such as high flame retardancy and solvent resistance.

(B) Structure of the Invention [Means for Solving the Problems] As a result of intensive research to achieve the above object, the present invention adopts ammonium phosphate as a flame retardant, and uses this ammonium phosphate in oil. In order to disperse uniformly in the modified phenolic resin, weakly acidic phosphoric acids were used as the acidic catalyst to act during the reaction between the drying oil and phenols, and the reaction between the drying oil and phenols was controlled to an appropriate level of reactivity. At this stage, ammonia is used as a neutralizing agent to neutralize phosphoric acids as an acidic catalyst, converting it into ammonium phosphate salt and uniformly dispersing it. They selected amines that have a burning effect and left them in the oil-modified phenolic resin after the reaction.

[Function] Phosphoric acids act as acidic catalysts in the reaction stage of drying oil and phenols, and act as flame retardants by forming ammonium phosphate salts with ammonia as a neutralizing agent, and also prevent the formation of ammonium phosphate salts. Since this is carried out simultaneously with or before the formation of a phenol resin, the water-soluble ammonium phosphate salt is uniformly dispersed in the oil-modified phenol resin that is the reaction product.

Since phosphoric acids are weakly acidic, a large amount of phosphoric acid can be added as an acidic catalyst, resulting in the production of a large amount of ammonium phosphate. It becomes possible to disperse.

It should be noted that even if a large amount of ammonium phosphate salt is present during the production reaction process of oil-modified phenol resin, at such a low molecular level, it will not inhibit the production reaction in any way, unlike polymerization during the crosslinking reaction in the conventional example. do not.

The drying oil used in the present invention is a vegetable oil such as tung oil, oiticica oil, dehydrated mustard oil, or linseed oil, and preferably tung oil or oiticica oil, which are highly reactive with phenols, are used alone or in combination. In addition, phenols are phenol,
Cresol, xylenol and other alkylphenols are used alone or in combination. Moreover, phosphoric acids are used as the acidic catalyst. Further, as the formaldehyde, 37% formalin, 42% formalin, paraformaldehyde, etc. are used. Moreover, amines are used as the basic catalyst.

The ratio of drying oil and phenols is not particularly limited, but based on the characteristics when used in electrical insulation laminates and copper-clad laminates for printed circuits, the ratio of drying oil to phenols is 25 parts per 100 parts (weight parts and below) of phenols. -75 parts is preferable. If it is less than 25 parts, the crosslinking density of the cured product is high and cracks are likely to occur when punching the laminate after forming it into a laminate. This is because delamination between the material layers and whitening around the punched holes are likely to occur. The amount of phosphoric acids added is 1 to 5% by weight based on the total amount of drying oil and phenols.
The reason for this limitation is that if it is less than 1% by weight, the reaction between the drying oil and phenols will be difficult to proceed, and if it exceeds 5% by weight, the flame retardant effect after turning into a resin will be large, but the reaction between the drying oil and phenols will not proceed. This is because control becomes difficult, and ammonium phosphate salts are likely to precipitate in the resinized varnish, causing problems in the storage of the varnish.

The temperature at which the drying oil and phenols are reacted in the presence of a phosphoric acid catalyst is not particularly limited, but is preferably in the range of 80 to 150°C. This is because if the temperature is less than 80°C, the reaction between the drying oil and phenols does not proceed easily, and if it exceeds 150°C, the reaction product tends to gel.

The reaction time between the drying oil and the phenol can be adjusted to a desired degree of reaction within the range of 15 minutes to 5 hours, although it depends on the reaction temperature.

The amount of ammonia added to neutralize phosphoric acids is not particularly limited, but is preferably 1.0 to 3.0 times the amount of phosphoric acid added. Further, the time to neutralize the phosphoric acids with ammonia may be at a stage before adding the aldehydes after the reaction between the drying oil and the phenols, or after the addition of the aldehydes.

The amount of aldehydes added to phenols is not particularly limited, but is 1.0 to 2
．． A 0-fold molar amount is preferred. It is desirable to use a large amount of the basic catalyst amines for the purpose of introducing nitrogen into the oil-modified phenolic resin, but the desired gelation time and It may be selected as appropriate so as to obtain resin properties such as viscosity. Furthermore, there is no problem in the scope of the present invention to further add phenols at the stage of the phenolic resin formation reaction.

The oil-modified phenolic resin obtained in this way is prepared by adding halogen-based flame retardants as needed in addition to the ammonium phosphate and organic amine flame retardants that remain uniformly dispersed in the oil-modified phenol resin. Prepare a flame-retardant oil-modified phenolic resin, impregnate it into a base material such as paper or glass cloth, and dry it to produce a base material impregnated with an oil-modified phenolic resin.The required number of sheets are stacked and molded under heat and pressure. This makes it possible to produce a laminate with good flame retardancy, punching workability, electrical properties, and solvent resistance.

Furthermore, if necessary, copper foil can be placed on one or both sides of the resin-impregnated base material and heated and pressure molded to produce a copper-clad laminate for printed circuits.

[Example] 100 g of tung oil, 200 g of phenol, and 9 g of orthophosphoric acid were placed in a reaction vessel, and after reacting at 110°C for 60 minutes, 9 g of 25% aqueous ammonia was added to neutralize it, and then 200 g of 42% formalin was added, Furthermore, 4 g of ethylenediamine was added and reacted under reflux under heating. When the gelation time of the oil-modified phenol resin reached 4 minutes, the water in the reaction system was dehydrated under reduced pressure. The obtained resin was dissolved and diluted with a mixed solvent of toluene/methanol in a weight ratio of 1/3. To this resin, 30 parts of a brominated epoxy resin having a bromine content of 49% was added as a bromine-based flame retardant to produce a flame-retardant oil-modified phenol resin.

This flame-retardant oil-modified phenolic resin was impregnated into a 0.25 mm thick kraft paper that had been previously treated with a low molecular weight water-soluble melamine resin to a resin content of 50%, and dried to produce a prepreg. Next, 8 sheets of this prepreg were subjected to flJI, adhesive-coated copper foil was placed on the surface, and heat and pressure molding was performed to produce a single-sided copper-clad laminate having a thickness of 1.6 mm. Table 1 shows the characteristics of this copper-clad laminate.

Comparative Example 100 g of tung oil, 200 g of phenol, and 0.09 g of P-toluenesulfonic acid were placed in a reaction vessel and reacted at 80° C. for 60 minutes, and then neutralized by adding 0.09 g of 25% aqueous ammonia. Next, 200g of 42% formalin was added,
Furthermore, 4 g of ethylenediamine was added, and the mixture was heated and dehydrated under reflux. The resulting resin was diluted by dissolving it in a mixed solvent with a weight ratio of toluene/methanol of 1/3, and 20 parts of triphenyl phosphate as a phosphoric acid ester flame retardant and 49 parts of bromine as a bromine flame retardant. % of brominated epoxy resin to produce a flame-retardant oil-modified phenolic resin.

[1 row margin] Table 1 A prepreg was produced using this flame-retardant oil-modified phenolic resin in the same manner as in the example, and a single-sided copper-clad laminate with a thickness of 1.6 mm was produced. Table 1 shows the characteristics of this copper-clad laminate.

(c) Effects of the invention As is clear from the above detailed description and property comparison, the flame-retardant oil-modified phenolic resin of the present invention has excellent flame retardancy and punching workability, as well as good electrical properties and solvent resistance. Therefore, the industrial value of the present invention is extremely large.

Patent applicant Risho Kogyo Co., Ltd.

Claims (1)

[Scope of Claims] 1. Drying oil and phenols are reacted in the presence of phosphoric acids as an acidic catalyst to reach an appropriate degree of reaction, and then ammonia as a neutralizing agent is added to the phosphoric acids as an acidic catalyst. is added to convert it into ammonium phosphate salt,
A method for producing a flame-retardant oil-modified phenolic resin, which is characterized by adding amines as a basic catalyst and reacting aldehydes. 2. The method for producing a flame-retardant oil-modified phenolic resin according to claim 1, wherein the phosphoric acid is orthophosphoric acid. 3. The method for producing a flame-retardant oil-modified phenolic resin according to claim 2, wherein the amount of orthophosphoric acid added is 1 to 5% by weight based on the total amount of drying oil and phenols.