JPH0513059B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing flame-retardant paper-phenolic resin laminates (including copper-clad laminates). BACKGROUND OF THE INVENTION In recent years, insulating materials, particularly laminates used in communication devices and electronic devices, are required to be punchable at room temperature or slightly higher temperature from the viewpoint of automation of processing equipment and energy saving. 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, from the viewpoint of safety, there is an increasing demand for flame retardancy for laminates used as insulating materials. Plasticizers make flame retardation very difficult and complicated. A method of making laminates flame retardant is to add flame retardants to phenolic resin. As a flame retardant element in flame retardants
Compounds containing Sb, As, B, N, halogen, P, etc. are often used. Particularly important elements include phosphorus, which is effective in blocking oxygen, carbonizing organic matter, and forming a carbonized film, and halogen, which is effective in trapping highly reactive radicals. Furthermore, 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, pentabromomonochlorocyclohexane, tetrabromomonochlorocyclohexane, 2,2-bis-[4-(2,3-
Examples include dibromopropoxy)-3,5-dibromophenyl]-propane, 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)propane, pentabromophenol, tribromophenol, and dibromophenol. The latter include glycidyl ethers of tetrabromophthalic anhydride, dibromophenol, or tribromophenol, 2,
Brominated epoxy resins such as diglycidyl ether of 2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane, allylates of brominated phenols, chlorendo acid, tetrachlorophthalic anhydride, etc. . 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, xylenyl diphenyl phosphate, and tris-(β-chloroethyl) Phosphate,
Tris (dibromopropyl) phosphate, tris-(dichloropropyl) phosphate, tris-(2,3-dibromopropyl) phosphate,
Tris-(bromochloropropyl)phosphate,
There are halogen-containing phosphoric acid esters such as phosphoric acid esters, and phosphorous 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 a phenol must be added to the allyl group in advance in the presence of an acidic catalyst, which adds one additional step to the synthesis. In addition, in order to satisfy 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 a phosphorus-based flame retardant is also used, the above-mentioned drawbacks tend to occur, and there is a limit to the amount of the phosphorus-based flame retardant used. In addition, as mentioned above, halogen-containing and phosphoric esters are
It has a halogen bonded to an aliphatic group and has poor heat resistance, so it cannot be used in paper-phenol laminates and copper-clad laminates that require heat resistance. As a result of intensive research to eliminate the above-mentioned drawbacks, we have arrived at the present invention. The present invention is characterized in that a paper base material impregnated with a predetermined amount of a phenolic resin varnish containing a reaction product obtained by reacting a phosphoric acid ester and a halogen-containing aromatic glycol as a flame retardant is heat-formed. It is something. Considering the transesterification reaction between phosphoric acid esters and halogen-containing aromatic glycols, the former is 3
Since the latter has two reaction points, the reaction product has a high molecular weight. By making it into a high molecular weight compound, when it is added to a phenolic resin to impart flame retardancy, it becomes difficult to ooze out from the cured phenolic resin, and the above-mentioned drawbacks of phosphoric acid esters can be overcome. In addition, the heat resistance, which was a drawback of halogen-containing phosphate esters, can be improved at the same time, and it is also possible to uniformly distribute phosphorus atoms and bromine atoms in the phenolic resin at a certain ratio, which improves flame retardancy. It is effective in improving the To explain the present invention in more detail, phosphoric acid esters and halogen-containing aromatic glycols are heated without a solvent or in a solvent in the presence of a basic catalyst to cause a transesterification reaction to obtain a flame retardant reaction product. As phosphoric acid esters, the general formula []
A compound as shown in is used.

[Formula] (However, R ₁ , R ₂ , and R ₃ represent an alkyl group or an aryl group, and may be the same or different from each other.)
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, Xylenyl diphenyl phosphate (XDP), Tris(-β
-chloroethyl) phosphate, tris-(dibromopropyl) phosphate, tris(bromochloropropyl) phosphate, triethyl phosphate, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, trilauryl phosphate, tri- Examples include ceyl phosphate, tristearyl phosphate, triolein phosphate, and tricylenyl phosphate. As the halogen-containing aromatic glycols, compounds represented by the general formula [] are used. [However, Z is

[Formula] (m, n=0-5), _-SO2 --O--S- represents a divalent bonding group. Y is (-O-CH ₂ CH ₂ )- or and p, q=1 to 10. X represents bromine or chlorine, and represents u and v=1 to 4. (m, n) (p, q) (u, v) may be the same or different. ] Halogen-containing aromatic glycols [ ] include
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)methane , bis-(3-bromo-4-β-hydroxyethoxyphenyl) ether, and the like. The reaction temperature should be at least the temperature at which the compounds [] and [] are uniformly dissolved.
170°C is preferred. Because the reaction is slow below 80℃,
Reaction time becomes longer. On the other hand, if it exceeds 250℃ []
Alternatively, this is because the decomposition reaction of [] also proceeds at the same time. The catalysts used in the transesterification reaction between [] and [] above include carbonates such as K ₂ CO ₃ , Na ₂ CO ₃ , MgCO ₃ , triethylamine, diethylamine,
Organic basic compounds such as benzyldimethylamine and fluorides such as KF, NaF, and CsF are used. The amount of catalyst is preferably 0.01 to 2% based on the total weight of the reaction compounds [], []; if it is less than 0.01%, the reaction is slow, and if it exceeds 2%, the properties of the base resin will be deteriorated by the catalyst. Any solvent may be used as long as it dissolves the compounds [] and [], but it is better to proceed with the reaction as solvent-free as possible. This is to make it easier to distill off alcohols and phenols by-produced from phosphoric esters under low pressure during or after the reaction. Regarding the reaction amount, []/[]=1/0.1~
The molar ratio is preferably 1/2.0, and can be changed as appropriate in consideration of the flame retardant method of the paper-phenol laminate and the characteristics of the laminate. The phenolic resin for paper-phenol laminates to which the halogen- and phosphorus-containing flame retardant synthesized by the method described above is added may be any resin commonly used for paper-phenol laminates. Examples include drying oil-modified phenolic resins, drying oil- and aromatic hydrocarbon formaldehyde resin-modified phenolic resins, polybutadiene-modified phenolic resins, and alkylphenol-modified phenolic resins for improving low-temperature punchability. Further, the halogen phosphorus-containing flame retardant used in the present invention can also be used in combination with the above-mentioned halogen flame retardants, phosphorus flame retardants, or inorganic flame retardants such as nitrogen flame retardants, antimony trioxide, and boron oxide.
The amount of flame retardant added is preferably 30 to 80 parts by weight per 100 parts by weight of phenol as a raw material for phenolic resin for laminates.
Parts by weight are used. There is no specific rule regarding when to add flame retardants, but if phenols are produced as a by-product from phosphoric acid esters, they should be added during the synthesis of phenolic resin for laminates while leaving the phenols in the reaction system. It is more advantageous in terms of cost because it eliminates the step of distilling off the phenol under reduced pressure. A paper base material impregnated with a predetermined amount of phenolic resin varnish containing this reaction product as a flame retardant is heat-formed together with copper foil as necessary to form a paper-phenolic resin laminate. Hereinafter, a specific explanation will be given by showing examples. Flame retardant synthesis example 1. 2.2-bis-(3.5-dibromo-4-β) was placed in a three-neck flask equipped with a stirrer, thermometer, and condenser
-Hydroxyethoxyphenyl)propane (Teijin Kasei brand name Fireguard 3600) 632g, triphenyl phosphate 326g K ₂ CO ₃ 9.5g and 170g
The temperature was raised to ℃ and allowed to react for 5 hours. While maintaining that temperature, the pressure was reduced to distill off the by-produced phenol. The product was then poured from the flask into a vat, cooled, and ground into a flame retardant. Bromine content
41.1% Phosphorus content 4.0% Flame retardant synthesis example 2 2,2-bis-(3,
490.5 g of 5-dibromo-4,β-hydroxyethoxyphenyl)sulfone (C), 340 g of cresyl diphenyl phosphate (D), and 4.2 g of K ₂ CO ₃ were added and reacted at 150° C. for 7 hours. The reaction rate for (C) was 95%, and the reaction rate for (D) was 65%. Used as a flame retardant. After the reaction was completed, it was used directly for the next synthesis of phenolic resin. Bromine content: 28.9% Phosphorus content: 3.7% Flame retardant synthesis example 3 2,2-bis-
Add 948 g of (3,5-dibromo-4-β-hydroxyethoxyphenyl)propane (E), 354 g of cresyl diphenyl phosphate (F), and 6.5 g of CsF.
The reaction was carried out at ℃ for 7 hours. The reaction mixture was used as a flame retardant. The reaction rate for (E) was 92%, and the reaction rate for (F) was 71%. The flame retardant was used as it was in the next phenol synthesis. Bromine content: 24.6% Phosphorus content: 2.4% Synthesis example of phenolic resin 1 (phenolic resin) 1000 g of tung oil and 2000 g of mp-cresol were added to a flask equipped with a stirrer, condenser, and thermometer.
1 g of PTS was added and reacted at 100°C for 2 hours. Next, 835 g of paraform, 250 g of methanol, and 120 g of aqueous ammonia were 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 250 g of toluene and 250 g of methanol were added to prepare a varnish. The resin content was 70% and the gelation time was 2 minutes and 45 seconds. Synthesis Example 2 of Phenol Resin (Phenol Resin) 250 g of tung oil and 500 g of m,p-cresol in a second flask equipped with a stirrer, a cooler, and a thermometer.
0.25g of PTS was added and reacted at 100°C for 2 hours. Next, the flame retardant synthesized in Flame Retardant Synthesis Example 2 was
g, 243 g of paraform, 70 g of methanol, and 30 g of aqueous ammonia were added and reacted 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. The resin content was 69.5% and the gelation time was 2 minutes and 40 seconds. Synthesis example 3 of phenolic resin (phenolic resin) 250 g of tung oil and 500 g of m, p-cresol in two flasks equipped with a stirrer, a condenser, and a thermometer.
0.25g of PTS was added and reacted at 100°C for 2 hours. Next, 460g of the flame retardant synthesized in Flame Retardant Synthesis Example 3,
243 g of paraform, 70 g of methanol, and 30 g of aqueous ammonia were added and reacted at 80°C. Gel time is 3
At the end of 10 minutes, the mixture was dehydrated and concentrated under reduced pressure. The reaction was terminated when the reaction solution became transparent, and toluene was added.
250g and 250g of methanol were added to make a varnish.
The resin content was 73%, and the gelation time was 2 minutes and 50 seconds. Kraft paper previously impregnated with a water-soluble phenolic resin was impregnated with a 50% resin varnish prepared according to the formulation shown in Table 1, and dried to produce a prepreg. Eight sheets of the prepreg were stacked, and a copper foil coated with an adhesive was stacked on one side and pressed at 150° C. and a pressure of 100 kg/cm ² for 70 minutes to produce a copper-clad laminate. As a comparative example, Fireguard 2000 and TPT alone were added to phenolic resin to create a varnish, and prepreg and copper-clad laminates were created 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] From the results in Table 1, the use of the flame retardant obtained in the present invention improves the trichlene resistance, air heat resistance, and UV ink adhesion among the properties of paper-phenol copper clad laminates. I can see that it is being done. Moreover, the laminates using the flame retardant obtained according to the present invention have small variations in the combustion time that indicates flame retardancy, and are also effective in flame retardancy. This is because phosphorus and bromine are uniformly dispersed.

Claims (1)

[Claims] 1. A paper base material impregnated with a predetermined amount of phenolic resin varnish containing a reaction product obtained by reacting phosphoric acid esters and halogen-containing aromatic glycols as a flame retardant is heat-formed. A method for producing a flame-retardant paper-phenolic resin laminate, characterized by: 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.