JPH0221404B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a brominated polyepoxy compound having a low saponifiable halogen content. The brominated polyepoxy compounds obtained by practicing the present invention are useful as varnish resins and sealants for electrical laminates, especially printed wiring boards (PCs). Brominated polyphenols, typified by diglycidyl ether of tetrabromobisphenol A, are used in combination with diglycidyl ether of bisphenol A because they provide cured products with excellent tracking resistance, heat resistance, and flame retardancy, and are used in electrical laminates. It is used as an impregnating material. In addition, the diglycidyl ether of tetrabromobisphenol A itself is used alone as a casting material and a flame retardant for polybutylene terephthalate and unsaturated polyester. Such diglycidyl ether of tetrabromobisphenol A has conventionally been prepared by adding 5 to 5 epihalohydrin to 1 mole of tetrabromobisphenol A.
Used in a ratio of 10 moles, 2 to 2.2 sodium hydroxide
molar aqueous solution was gradually added over 2 to 3 hours,
It is manufactured by reacting at 60-90℃. However, the diglycidyl ether of tetrabromobisphenol A obtained by this production method and represented by the following formula () is the following formula () contains a compound having the structural formula shown in
remain. A high saponifiable chlorine content slows down the curing speed of the polyepoxy compound and lowers the electrical properties and mechanical properties of the resulting cured product after boiling in boiling water, so a further dehydrochlorination reaction is performed to make it saponifiable. It is necessary to reduce the chlorine content to below 0.1% by weight. This re-dehydrochlorination reaction is generally carried out by distilling off excess epichlorohydrin and then diluting it with an aromatic solvent such as toluene or xylene or a ketone solvent such as methyl isobutyl ketone or methyl ethyl ketone to give a concentration of 1 to 20% water. Add sodium oxide aqueous solution to the remaining hydrolyzable chlorine at 1.1
~10 times the equivalent is added and carried out at 60-90°C. However, with this method, the amount of hydrolyzable chlorine is 0.1% or less.
In particular, it is difficult to reduce it to 0.05% or less even under the severe conditions mentioned above.
In that case, there is a risk that undesirable side reactions such as hydration and polymerization of the epoxy group may occur. In this case, if you use a large amount of a water-soluble solvent such as acetone, methyl alcohol, ethyl alcohol, or propyl alcohol instead of the above-mentioned hydrophobic solvent, it is possible to reduce the hydrolyzable chlorine to 0.1% or less even under relatively mild conditions. However, since water-soluble solvents are difficult to separate from water, these organic solvents are mixed into wastewater, making wastewater treatment difficult and production costs high. The present invention provides a method for producing a brominated polyepoxy compound having a saponifiable halogen content of 0.1% by weight or less without carrying out such re-dehydrochlorination reaction. an alkali in which the proportion of epihalohydrin is less than 0.6 to 1.5 mol per equivalent of the phenolic hydroxyl group of the phenol, and the alkali metal hydroxide is contained in a proportion of 0.01 to 0.8 mol per equivalent of the phenolic hydroxyl group of the brominated polyphenol; A halohydrin ether of a brominated polyphenol is produced by reacting it in the presence of an aqueous solution of metal hydroxide and an organic solvent containing 5 to 200% by weight of the resulting brominated polyepoxy compound, followed by hydration of an alkali metal. The present invention provides a method for producing a brominated polyepoxy compound, characterized in that the dehydrohalogenation reaction is carried out while removing water from the reaction system. In the practice of the present invention, examples of brominated polyphenols include tetrabromobisphenol A, tetrabromobisphenol F, and tetrabromobisphenol S represented by the following formula () at the meta position.
Tetrabromobisphenols having a Br group; [In the formula, A is -CH ₂ -,

[Formula] -SO ₂ - group] General formula () [In the formula, R is H, Br, or an alkyl group having 1 to 9 carbon atoms, and n is a number of 1 to 5]. Next, as the epihalohydrolidone, epichlorohydrin, epibromohydrin, epiiodohydrin, and β-methylepichlorohydrin can be used. Examples of the alkali metal hydroxide that is the catalyst for the first-stage addition reaction include potassium hydroxide, sodium hydroxide, and lithium hydroxide. Among these, sodium hydroxide is the cheapest. This alkali metal hydroxide is added to the reaction system as an aqueous solution. In addition to these large oxides of alkali metals, known addition catalysts such as quaternary ammonium salts such as tetramethylammonium bromide and phosphonium salts such as tetramethylphosphonium chloride may be used. The organic solvent used as a solvent during the addition reaction is compatible with the raw materials epihalohydrin, brominated polyphenol, and the desired product brominated polyepoxy compound,
Specifically, aliphatic monohydric alcohols such as n-butanol and octanol; glycols such as ethylene glycol, diethylene glycol, and propylene glycol; cyclic alcohols such as benzyl alcohol and cyclohexanol; methyl ethyl ketone, methyl isobutyrol ketone, and methyl isopropyl ketone. Ketones such as , cyclohexanone; n
-Ethers such as butyl ether, 1,4-dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; methyl acetate, ethyl acetate, isobutyl acetate, acetic acid n-
Examples include esters such as butyl, ethyl formate, propyl formate, and n-butyl formate. Among these, those with a boiling point exceeding 100℃ are preferable, and among them, butanol, methyl ethyl ketone, and methyl isobutyl ketone are preferable because they can be easily separated from water.In particular, methyl isobutyl ketone (boiling point 117℃) has a low solubility in water and has a high specific gravity. is as small as 0.8, which is optimal. The charging ratio of each component in the addition reaction is as follows. Phenolic hydroxyl group of brominated polyphenol 1
For equivalent weight, the epihalohydrin is less than 0.6 to 1.5 mol, preferably 0.7 to 1.4 mol, more preferably 0.8 mol.
The proportion is ~1.4 mol. If the amount is less than 0.6 mol, the product will be a high molecular weight resin with almost no epoxy groups, and it will not be possible to obtain a heat-infusible cured product with a three-dimensional structure using the curing agent. If 1.5 mol or more is used, a diglycidyl ether of brominated polyphenol in which n is 0 in the previous formula (1) is obtained, which is useful as a flame retardant for phenolic resins, but it is not suitable for use in varnishes. When stored by dissolving it in isobutyl ketone, toluene, etc., it has the disadvantage that it tends to recrystallize and precipitate. Also, the use of excess epihalohydrin increases recovery costs. Next, the alkali metal hydroxide that is the addition reaction catalyst is 0.01 to 0.8 mol, preferably 0.01 to 0.8 mol, per equivalent of the phenolic hydroxyl group of the brominated polyphenol.
Used in a proportion of 0.1-0.5 mole. If it is less than 0.01 mol, the addition reaction will take a long time. If it is used in an amount exceeding 0.8 mol, the ring-closing reaction and the polymerization reaction between the epoxy group generated by the ring-closing reaction and the residual phenol proceed during the addition reaction, which is undesirable because the gel content increases. The organic solvent is used in an amount of 5 to 200% by weight, preferably 10 to 50% by weight of the target brominated polyepoxy compound to facilitate the addition reaction and ring closure reaction. In conventional production methods, epihalohydrin is used in excess of 5 to 10 moles per mole of brominated polyphenol, and the brominated polyphenol is dissolved in epihalohydrin, but in the present invention, epihalohydrin is used in excess of 1.2 to 3 moles.
Since the epihalohydrin cannot completely dissolve the brominated polyphenol because the amount is less than a molar amount, an organic solvent that dissolves the brominated polyphenol is blended to facilitate the addition reaction. The addition reaction is carried out at 80 to 120°C for 1/6 to 3 hours, preferably at 95 to 110°C for 1/3 to 1 hour, so that 95% or more of the phenolic hydroxyl groups of the brominated polyphenol are converted to halohydrin ether groups. can be converted. When the addition reaction is carried out at a temperature where the reaction reagent boils, it is preferable to separate the azeotropic water and remove it from the system, and return the epihalohydrin and organic solvent to the reaction reagent. However, the removal of water can be omitted by selecting the aqueous solution of alkali metal hydroxide used in the addition reaction in an amount as small as possible within the conditions of the present invention. The halohydrin ether of brominated polyphenol obtained by this addition reaction has a saponifiable chlorine content of about 6 to 8% by weight and an epoxy equivalent of about 850 to 4000.
belongs to. Following the addition reaction, using an alkali metal hydroxide as a raw material, the number of moles of the alkali metal hydroxide used in the addition reaction and the number of moles used are newly added to one equivalent of the phenolic hydroxyl group of the brominated polyphenol. The sum of the moles of alkali metal hydroxides is 1.0
~1.2 mol, preferably 1.05-1.15 mol,
Add gradually. Addition is at a temperature of 90-110℃, 5
It is preferable to carry out the addition over a period of 120 minutes, preferably 10 to 60 minutes, since the addition can be carried out without cooling the addition reaction product. After the addition of the alkali metal hydroxide is completed, at 60-120°C, preferably 85-120°C under reduced pressure, or
1 at 100-150℃ under normal pressure, preferably 100-120℃
The dehydrohalogenation reaction is carried out for 10 hours, preferably 2 to 5 hours while removing water from the reaction system. This dehydrohalogenation reaction is carried out at a temperature at which the organic solvent and water azeotrope, and the water is azeotroped with the organic solvent and substantially removed from the reaction system, and the organic solvent from which water has been separated is recycled into the reaction system. Let me do it. Also, 1~5Kg/ ^cm2
It can also be carried out by heating at a temperature of 100 to 150° C. for 1 to 5 hours under pressure of G. The former method is more preferable because a brominated polyepoxy compound with a lower content of saponifiable halogen can be obtained and a pressurizing device is not required. However, if the objective is to obtain a brominated polyepoxy compound with a good hue, the reduced pressure method or the latter pressurized method is used. Note that, if necessary, it is possible to add an organic solvent to the reaction system before the dehydrohalogenation reaction. In the present invention, since a brominated polyphenol having a bromine group at the meta position is used as a raw material and the alkali metal hydroxide is consumed by the addition reaction, the alkali concentration in the system is low and the ring-closing reaction is difficult to occur. Therefore, the dehydrohalogenation reaction is carried out in the absence of almost any water and at a temperature of 60 to 120°C under reduced pressure and 100°C under increased pressure or normal pressure.
It is necessary to carry out the process under harsh temperature conditions of ~150℃. In addition, in the halohydrin ether produced in the addition reaction, trans-epochlation between saponifiable halogen and epihalohydrin is difficult to occur, so the amount of dihalogenhydrin produced as a by-product is extremely small or undesirable. After the completion of the dehalogenation reaction, an organic solvent is added if necessary, water is added for washing, the alkali metal halide is separated from the water, and the organic solvent is then distilled off under reduced pressure at a temperature of 160°C or lower. A brominated polyepoxy compound can be obtained by the process. The brominated polyepoxy compound thus obtained has an epoxy equivalent of 330 to 800, a saponifiable halogen content of 0.1% by weight or less, and is solid at 20°C. When tetrabromobisphenol A is used as a raw material, in the general formula (),
It is a polyepoxy compound in which n is 0 to 1, preferably 0.08 to 0.5. A varnish for prepreg is prepared by blending this brominated polyepoxy compound with a curing agent, an organic solvent, an accelerator if necessary, and other polyepoxy compounds. As such a curing agent, dicyandiamide, orthotolylbisguanidine, tetramethylguanidine, triethylenetetramine, diaminodiphenylmethane, etc. can be used. Examples of accelerators include tertiary amines having an aromatic ring such as benzyldimethylamine, α-methylbenzyldimethylamine, and 2-(dimethylaminomethyl)phenol, alicyclic tertiary amines such as N-methylmorpholine, and BF ₃ -Amine complex salts etc. can be used. The solvent varies depending on the curing agent used, but acetone,
Methyl cellosolve, methyl ethyl ketone, dimethyl formamide, methanol, etc. are used alone or in combination. For example, when the curing agent is diaminodiphenylmethane, acetone is suitable, and when the curing agent is dicyandiamide, dimethylformamide or methyl cellosolve is suitable. For example, the prepreg for PC production is made by using glass fibers in a ratio such that the varnish having the above composition is used as a reinforcing material at room temperature, and the amount of resin is 15 to 75% by weight, preferably around 50% by weight.
The prepreg is impregnated with polyepoxy resin as a reinforcing material by impregnating it with linter paper, leading it into a drying chamber set at 120 to 180℃, and drying it for 2 to 10 minutes to remove the organic solvent (B-stage). is manufactured. This prepreg is cut into sheets,
These multiple sheets are stacked with adhesive-coated copper foil, and then
20~ at a pressure of 10~100Kg/ ^cm2 at a temperature of 140~180℃
Press molding is performed for 100 minutes, and the resin is three-dimensionally crosslinked to produce a copper-clad laminate. Next, after printing the circuit on the copper foil, a photoresist layer is provided, the photoresist is cured by irradiation with light, the uncured photoresist is washed away with a weak alkaline solution, and the photoresist film is formed by acid etching. It is manufactured by dissolving the uncoated copper parts, washing with water, and removing the photoresist film cured with methylene chloride or the like. PCs with copper wire circuits on the surface of resin laminates are widely used in the fields of calculators and microcontrollers. The brominated polyepoxy compound obtained by carrying out the present invention is a pale yellow solid, and the varnish prepared using it has excellent storage stability. Also,
Because the saponifiable halogen content is low, this brominated polyepoxy compound can be used for electrical laminates, resin encapsulation of ICs and LSIs, molding, transmolding, etc.
This material is suitable for casting, etc. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 Tetrabromobisphenol was placed in a stainless steel flask equipped with a cooling device, a thermometer, a reflux condenser, and a dropper for an aqueous sodium hydroxide solution.
A1000g (approximately 1.84 mol), epichlorohydrin 340g
(approximately 3.68 mol) and methyl isobutyl ketone
340g of these reaction reagents were charged and the temperature of these reaction reagents was raised to 42°C. Next, 66g of a 50% aqueous solution of sodium hydroxide.
(0.825 mol NaOH solids) was added all at once into the flask, then the temperature at which the reaction reagents boiled (approximately 100 mol) was added to the flask.
The addition reaction was carried out at the same temperature for 30 minutes.
During this time, the azeotropic water, epichlorohydrin, and methyl isobutyl ketone were cooled and returned to the flask. A portion of this addition reaction product (1320 g) was taken out, dissolved in methyl isobutyl ketone, washed with water, and the chlorohydrin ether of tetrabromobisphenol A obtained by distilling off methyl isobutyl ketone under reduced pressure at 110°C. The physical properties were as follows. Saponifiable chlorine content 7.82% by weight Epoxy equivalent 2800 Phenolic hydroxyl group 0.010meq/g (phenolic hydroxyl group conversion rate 99.3%) Next, 50% aqueous solution of sodium hydroxide
After dropping 270 g (3.38 mol) into the flask at a temperature of about 100°C over 20 minutes, 2160 g of methyl isobutyl ketone was added at once and heated to bring the reaction reagent into an azeotropic state. Reagent temperature is 117
It was kept until it reached ℃. During this time, water was azeotropically distilled together with methyl isobutyl ketone, separated and removed out of the flask by a separating funnel, and methyl isobutyl ketone from which water had been separated was returned to the flask. When the temperature reached 117°C, the heating was terminated to complete the dehydrochlorination reaction. Then, hot water was added, and the water washing process of mixing and standing separation was repeated until the pH of the wastewater was 7.5 or less, and the by-product was produced. Separate the salt. Methyl isobutyl ketone was removed from the organic solvent layer from which the aqueous layer was separated at 117°C to obtain 1190 g of a brominated polyepoxy compound having the following physical properties. Epoxy equivalent: 380 Saponifiable chlorine content: 0.03% by weight Phenolic hydroxyl group content:
Less than 0.001meq/g Gardner viscosity (70% butyl carbitol solution): K Bromine content: 78.9% by weight Appearance: pale yellow solid Examples 2 to 5 In Example 1, the types and amounts of reaction reagents were as shown in Table 1. A brominated polyepoxy compound having the physical properties shown in Table 1 was obtained in the same manner except for the following. Comparative Example 1 Tetrabromobisphenol in the flask
A1000g (approx. 1.84 mol), epichlorohydrin 850g
(approximately 9.2 mol), then 294 g (3.68 mol) of 50% aqueous sodium hydroxide solution was added at 80°C.
The reaction was allowed to proceed at the same temperature for 4 hours. After the reaction was completed, excess epichlorohydrin and water were distilled off under reduced pressure. Then 600g of methyl isobutyl ketone, 50%
Add 90g of sodium hydroxide aqueous solution to the product,
After reacting at 80°C for 4 hours, 1900 g of methyl isobutyketone was added, and after further washing with water, methyl isobutyl ketone was distilled off under reduced pressure to produce diglycidyl brominated bisphenol A having the physical properties shown in Table 1. Obtained 1150g of ether. Example 6 The addition reaction was carried out in the same manner as in Example 1, except that 1.7 g of tramethylammonium chloride was used as a catalyst and the addition reaction temperature was 90°C.
The physical properties of the obtained product were as shown in Table 1. Example 7 After carrying out the addition reaction and addition reaction of the remaining 50% aqueous sodium hydroxide solution in the same manner as in Example 1, the dehydrochlorination reaction was carried out under reduced pressure (18 to 750 mmHg) by azeotropically adding methyl isobutyl ketone and water to the system. I went outside removing it. After the reaction was completed, the pressure was returned to normal pressure, 2160 g of methyl isobutyl ketone was added to the product, and water washing and solvent removal were performed in the same manner as in Example 1 to obtain a brominated epoxy compound having the physical properties shown in Table 1. Example 8 After carrying out the addition reaction of Example 1, 270 g of a 50% aqueous solution of sodium hydroxide was dropped into the flask at 99° C. over 20 minutes. Next, the reaction system was set to 120
The temperature was raised to 0.degree. C., and a dehydrochlorination reaction was carried out for 2 hours under a pressure of 1.2 Kg/ ^cm.sup.2 G (during this time, water did not come out of the reactor). After cooling to 40° C., a purification step was carried out in the same manner as in Example 1 to obtain a brominated polyepoxy compound having the physical properties shown in Table 1. Storage stability evaluation 50 ml of a 60% by weight methyl ethyl ketone solution of the brominated polyepoxy compound obtained in Examples 1 to 8 and Comparative Example 1 was placed in a 100 ml Erlenmeyer flask, and this was stored in a refrigerator at 10°C for 6 months. When the varnish did not precipitate, the storage stability of the varnish was evaluated as stable, and the varnish that precipitated crystals was evaluated as having poor storage stability. The results are shown in Table 1.

【table】

[Table] Example of manufacturing a laminate To 40 parts by weight of an 80% methyl ethyl ketone solution of the diglycidether of tetrabromobiphenol A obtained in Example 1 and Comparative Example 1, polymerized bisphenol manufactured by Yuka Ciel Epoxy Co., Ltd. was added. Diglycidyl ether of A “Epicote 1001-B-80” (product name)
60 parts by weight, 0.16 parts by weight of benzyldimethylamine, and 3.2 parts by weight of dicyandiamide dissolved in 40 parts by weight of methyl cellosolve and 43.2 parts by weight of the solution were mixed.
A varnish was prepared. A glass cloth "7628/1040/AS431" (trade name) manufactured by Asahi Miyu Abel Co., Ltd. was impregnated with this varnish, and then placed in a drying room at 150° C. for 6 minutes to remove the solvent and obtain a prepreg. This prepreg was cut, 8 prepreg sheets obtained were stacked, preheated at 160°C under atmospheric pressure for 2 minutes, and compression molded at the same temperature for 45 minutes at 30 kg/cm ^2. A laminate with the physical properties shown was obtained (glass fiber content 55%).

【table】

Claims (1)

[Scope of Claims] 1. Brominated polyphenol and epihalohydrin are mixed in a ratio of 0.6 to less than 1.5 moles of epihalohydrin per equivalent of phenolic hydroxyl group of the former brominated polyphenol, and the alkali metal hydroxide is brominated. The reaction is carried out in the presence of an aqueous solution of an alkali metal hydroxide in a proportion of 0.01 to 0.8 mol per equivalent of the phenolic hydroxyl group of the polyphenol and an organic solvent in a proportion of 5 to 200% by weight of the brominated polyepoxy compound to be produced. A brominated polyepoxy compound characterized in that after producing a halohydrin ether of a brominated polyphenol, an alkali metal hydroxide is added and a dehydrohalogenation reaction is carried out while removing water from the reaction system. manufacturing method. 2 The subsequent dehydrohalogenation reaction was carried out at 60°C under reduced pressure.
~120℃ or 100~150℃ under normal pressure, and
2. The production method according to claim 1, wherein the process is carried out at a temperature at which the organic solvent and water are azeotropic, and the water is azeotropically removed with the organic solvent, and the organic solvent is circulated through the reaction system. 3. The production method according to claim 1, wherein the brominated polyphenol is tetrabromobisphenol A having a Br group at the meta position. 4 Epihalohydrin is 0.6 per equivalent of phenolic hydroxyl group of tetrabromobisphenol A
4. The method of claim 3, wherein the amount is 1.4 to 1.4 equivalents.