JPH0558016B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing flame-retardant paper-phenolic resin laminates (including copper-clad laminates). [Prior Art] Recently, in order to automate processing equipment and save energy, there has been a demand for laminates used as insulating materials for communication equipment and electronic equipment to be able to be punched at room temperature or slightly higher temperature. There is. Therefore, phenolic resins made by combining various alkyl phenols with phenols and plasticizing them with drying oils, etc., are usually used as resins for low-temperature punchable laminates. However, there is an increasing demand for flame retardant laminates used as insulating materials from the viewpoint of safety. From the perspective of flame retardancy, plasticizers such as drying oil used to improve punching workability are difficult and complicated to make flame retardant.Phenol resins and flame retardants are used to make laminates flame retardant. A method of adding . As a flame retardant element in flame retardants
Compounds containing group elements of the periodic table, such as Sb, As, P, and N, as well as halogens, B, and P, are often used. Particularly important elements include oxygen blocking,
There are phosphorus, which is effective in carbonizing organic matter and the formation of carbonized coatings, and halogen, which is effective in trapping highly reactive radicals. Moreover, since these compounds exhibit a synergistic effect with each other, compounds containing phosphorus and halogen in the molecule are desired. There are two types of brominated flame retardants: additive and reactive; the former include decabromodiphenyl ether, pentabromotoluene, pentabromodiphenyl ether,
Hexabromocyclododecane, pentabromomonochlorohexane, tetrabromomonochlorocyclohexane, 2,2-bis-[4-(2,3-dibromopropoquine)-3,5-dibromophenyl]-propane, 2,2-bis -(3,5-dibromo-4
-hydroxyphenyl)propane, pentabromophenol, tribromophenol, and dibromophenol, the latter including the glycidyl ether of tetrabromophthalic anhydride, dibromophenol, or tribromophenol, 2,2-bis-(3,5 Examples include brominated epoxy resins such as diglycidyl ether of -dibromo-4-hydroxyphenyl)-propane, arylated products of brominated phenols, chlorendo acid, and tetrachlorophthalic anhydride. Most phosphorus-based flame retardants are additive types, and some are halogen-containing types. For example, phosphoric acid esters such as tricresyl phosphate, cresyl diphenyl phosphate, triphenyl phosphate, diphenyl octyl phosphate, tributyl phosphate, xylyl diphenyl phosphate, and tris-(β-chloroethyl) phosphate. , tris (dibromopropyl) phosphate, tris-(dichloropropyl) phosphate, tris-
Examples include halogen-containing phosphate esters such as (2,3-dibromopropyl) phosphate and tris-(bromochloropropyl) phosphate, and phosphite esters such as triphenyl phosphite. Additive bromine-based flame retardants and phosphorus-based flame retardants do not react with resins, so they easily bleed out (bleed).
This causes a decline in properties such as UV ink adhesion. Reactive brominated flame retardants require a large amount of cost to introduce epoxy groups or allyl groups.
Since brominated epoxy resins tend to react with phenols, they have drawbacks such as poor storage stability of phenolic resin varnishes and poor storage stability of prepregs. When a bromine compound having an allyl group is used in a phenolic resin, there is a drawback that the phenol must be added to the aryl group in advance in the presence of an acidic catalyst, which adds one additional step to the synthesis. Furthermore, in order to achieve flame retardancy using only a brominated flame retardant, a large amount of flame retardant must be used, which increases costs. Brominated flame retardants and phosphorus flame retardants have a synergistic effect, and it is preferable to use both in combination for flame retardation of paper-phenol laminates and copper-clad laminates. However, when phosphorus-based flame retardants are used together, the above-mentioned drawbacks tend to occur.
There are limits to the amount of phosphorus-based flame retardants that can be used. Further, as mentioned above, halogen-containing and phosphoric acid esters have a halogen bonded to an aliphatic group and have poor heat resistance, so they cannot be used in paper-phenol laminates and copper-clad laminates that require heat resistance. [Problems to be Solved by the Invention] The present invention aims to provide a paper-phenol resin laminate having excellent flame retardancy and heat resistance. [Means for solving the problems] The present invention provides a phenolic resin varnish containing a reaction product obtained by reacting a phosphoric acid ester, a halogen-containing aromatic glycol, and a halogen-containing aromatic alcohol as a flame retardant. The method is characterized in that a paper base material impregnated with a predetermined amount is heated and formed. Considering the transesterification reaction between phosphoric acid ester 1 and halogen-containing aromatic glycol 2 and halogen-containing alcohol 3, there are three reaction points for phosphoric acid ester 1 and two reaction points for halogen-containing aromatic glycol 2. Point, since halogen-containing aromatic alcohol 3 has one reaction site, it is possible to adjust the molecular weight of the reaction product by changing the mixing ratio of 1 and 2, and it is possible to adjust the molecular weight of the reaction product by changing the mixing ratio of 1 and 3. This is advantageous because it is possible to control the halogen content of the reaction product. By increasing the halogen content, it is possible to reduce the amount added, and by using a high molecular weight compound, it is possible to prevent leaching. For the above reasons, the above-mentioned drawback that phosphoric acid esters tend to bleed can be overcome. In addition, the heat resistance, which was a drawback of halogen-containing phosphate esters, can be improved at the same time.Furthermore, it is possible to uniformly distribute phosphorus and bromine atoms in the phenolic resin at a constant ratio, which improves flame retardancy. It is effective in improving the To explain the present invention in more detail, phosphoric acid esters, halogen-containing aromatic glycols, and halogen-containing aromatic alcohols are heated in the presence of a basic catalyst without a solvent or in a solvent to cause a transesterification reaction, resulting in a flame retardant reaction. Get the product. As the phosphoric acid esters, compounds represented by the general formula [] are used. However, R ₁ , R ₂ and R ₃ represent an alkyl group and an aryl group, and may be the same or different. Phosphate esters [] that can be used in the present invention include tricresyl phosphate (TCP), cresyl diphenyl phosphate (CDP), triphenyl phosphate (TPP), diphenyl octyl phosphate, tributyl phosphate, Xyleldiphenyl phosphate (XDP) tris(-β-
Chloroethyl) phosphate, tris-(dibromopropyl) phosphate, tris-(dibromopropyl) phosphate, tris(bromochloropropyl) phosphate, triethyl phosphate, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, tributoxyethyl phosphate , trilauryl phosphate, triceyl phosphate, tristearyl phosphate, triolein phosphate, tricylenyl phosphate, etc. As the halogen-containing aromatic glycols, compounds represented by the general formula [] are used. However, Z

[Formula] (m, n=0-5),

[Formula] -SO ₂ -O-, -S- represents a divalent bonding group. Y is -(O- _CH2 - _CH2- ) or

[Formula] is shown and p, q = 1 to 10. X represents bromine or chlorine, u, v=1-4
shows. (m, n) (p, q) (u, v) may be the same or different. Halogen-containing aromatic glycols []
2,2-bis-(3,5-dibromo-4-β-hydroxyethoxyphenyl)propane, bis-
(3,5-dibromo-4-β-hydroxyethoxyphenyl)sulfone, bis-(3,5-dibromo-4-β-hydroxyethoxyphenyl)methane, bis-(3,5-dibromo-4-β) -hydroxyethoxyphenyl) ether, 2,2-bis-(3-bromo-4-β-hydroxyphenyl)
Propane, bis-(3-bromo-4-β-hydroxyethoxyphenyl)sulfone, bis-(3-
Bromo-4-β-hydroxyethoxyphenyl)
Examples include methane and bis-(3-bromo-4-β-hydroxyethoxyphenyl) ether. As the halogen-containing aromatic alcohols, compounds represented by the general formulas [] and [] are used. However, R represents hydrogen or an alkyl group. X represents bromine or chlorine, m+p=5, m'+p'=5. Y is (-CH ₂
CH ₂ −O)− or

〔Example〕

The present invention will be specifically explained below with reference to examples. Flame retardant synthesis example 1 2,2-bis-(3,5-dibromo-4-β-hydroxyethoxyphenyl)propane 632 g (1 mol) was placed in a three-necked flask equipped with a stirrer, a thermometer, and a cooling tube. ,4,6-tribromophenyl-β-hydroxyethyl ether 375g (1
mol), 652 g (2 mol) of triphenyl phosphate, and 14.1 g of anhydrous potassium carbonate were added, and the reaction was continued at 150°C for 10 hours. After the reaction was completed, the temperature was raised to 170°C, and by-product phenol was distilled off under reduced pressure. Next, the reaction product in the flask was poured into a vat, cooled, and ground into a flame retardant. Bromine content 39.6
Weight% (same below) phosphorus content 4.4%. Flame retardant synthesis example 2 In a flask similar to the above, 444 g (1.5 mol) of 2,4 dibromophenyl-β-hydroxyethyl ether and 652 g (2 mol) of triphenyl phosphate were added.
5.5 g of anhydrous potassium carbonate was added and reacted at 150°C for 7 hours. After confirming that there was no unreacted dibrome compound by high performance liquid chromatography (HLC), 392.4 g (0.6 mol) of bis(3,5-dibromo-4-β-hydroxyethoxyphenyl) sulfone and anhydrous potassium carbonate were added. A further 5.5 g was added and the reaction was carried out at 170°C for 4 hours. After the reaction was completed, the by-product phenol was distilled off under reduced pressure while maintaining the temperature. When the distillation of phenol stopped, the reactant in the flask was poured into a vat, cooled, and pulverized to obtain a flame retardant. The yield is 34.5% bromine content and 4.9% phosphorus content. Flame retardant synthesis example 3 2,2-bis-
(3,5-dibromo-4-β-hydroxyethoxyphenyl)propane [A] 126.4g (0.2mol)
and cresyl diphenyl phosphate [B] 680g
(2 mol) and 4.0 g of CsF were added and reacted at 130°C for 3 hours. After confirming by HLC that [A] has completely reacted, add triethylene glycol to the reaction product.
170 by adding 926 g (2 moles) of mono-2,4,6-tribromophenyl ether [C] and 4.0 g of CsF.
The reaction was carried out at ℃ for 5 hours. The respective reaction rates were 100% for [A], 100% for [B], and 97% for [C]. This reaction mixture was used as a flame retardant. After the reaction was completed, it was used directly for the next synthesis of phenolic resin.
The bromine content of the reaction product excluding the by-product phenolic resin is 35.9% and the phosphorus content is 4.1%. Synthesis example of phenolic resin 1 (phenolic resin) Tung oil 1000g m.p-cresol 2000g, PTS1 in a 5 flask equipped with a stirrer, condenser, and thermometer.
g and reacted at 100°C for 2 hours. Next, paraform 833g methanol 250g ammonia water 120g
was added and reacted at 80°C. The reaction was monitored by the gelation time on a hot plate at 160°C, and when the gelation time reached 3 minutes, the mixture was dehydrated and concentrated under reduced pressure. When the reaction solution became transparent, the reaction was terminated and 250g of toluene was added.
250g of methanol was added to make a varnish. Resin content
The 70% gelation time was 2 minutes and 45 seconds. Synthesis Example 2 of Phenol Resin (Phenol Resin) Tung oil 250g m.p-cresol 500g PTS 0.25g in 2 flasks equipped with a stirrer, condenser, and thermometer
was added and reacted at 100°C for 2 hours. Next, add 320g of the flame retardant synthesized in Flame Retardant Synthesis Example 3 to paraform.
Add 243g to 70g of methanol and 30g of ammonia water.
The reaction was carried out at 80°C. When the gelation time reached 3 minutes, the mixture was dehydrated and concentrated under reduced pressure. The reaction was terminated when the reaction solution became transparent, and 130 g of toluene and 130 g of methanol were added to prepare a varnish. Resin content 69.5
The % gelation time was 2 minutes and 40 seconds. Using the synthesized flame retardant and phenolic resin, a phenolic resin varnish for laminates was prepared according to the formulation shown in Table 1. Then, apply the varnish shown in Table 1 to the kraft paper that has been pre-impregnated with water-soluble phenolic resin.
After adjusting to 50%, it was impregnated and dried to create a prepreg. A predetermined number of sheets of the prepreg were stacked, a copper foil coated with an adhesive was layered on one side, and pressure was applied at 150° C. and a pressure of 100 kg/cm ² for 70 minutes to produce a copper-clad laminate with a thickness of 1.6 mm. As a comparative example, tetrabromobisphenol A and
A varnish was made by adding TPP alone to a phenolic resin, and a prepreg and a copper-clad laminate were also made in the same way. The characteristics of the copper-clad laminate were measured according to the measurement method described in JIS-C-6481 and UL-94. The results are shown in Table 1.

【table】

〔Effect of the invention〕

According to the present invention, a paper-phenol resin laminate having excellent heat resistance and flame retardancy was obtained.

Claims (1)

[Scope of Claims] 1. A predetermined amount of phenolic resin varnish containing a reaction product obtained by reacting phosphoric acid esters, halogen-containing aromatic glycols, and halogen-containing aromatic alcohols as a flame retardant is impregnated and adhered. A method for producing a flame-retardant paper-phenolic resin laminate, which comprises thermoforming a paper base material. 2. The method for producing a flame-retardant paper-phenolic resin laminate according to claim 1, wherein the phosphoric esters are phosphoric esters having an aromatic ring.