JPH0684414B2 - Process for producing phenol-modified aromatic hydrocarbon formaldehyde resin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a phenol-modified aromatic hydrocarbon formaldehyde resin having excellent heat resistance, which is obtained by reacting an aromatic hydrocarbon formaldehyde resin with phenols. . More specifically, the present invention uses a phenol-modified aromatic hydrocarbon formaldehyde resin containing an aromatic hydrocarbon formaldehyde resin having a diarimethane content of 5% by weight or less and a xylenol value of 15 mol / kg or more as the aromatic hydrocarbon formaldehyde resin. The present invention relates to a method for producing a resin.

[Prior art and its problems]

A phenol-modified aromatic hydrocarbon formaldehyde resin is already known, and this modified resin is generally used as a laminated product, a molded product, and a coating material in the electric and electronic fields that require more moisture resistance and electrical characteristics than a general-purpose phenol resin. .

For example, a known novolak type phenol-modified xylene resin is a normal xylene formaldehyde resin obtained from meta-xylene and formaldehyde, and phenols are reacted under an acidic condition, and if excess phenols remain, formaldehyde is further added. It is produced by a method such as post-condensation.

The novolac-type phenol-modified xylene resin thus obtained is heat-cured by hexamine like ordinary phenol novolac, so that inorganic fillers such as glass fiber, asbestos, mica, and silica are used as molding materials. Although heat- and pressure-molded molded products have excellent long-term heat deterioration resistance, they do not have a sufficiently high glass transition temperature and their strength during heating is low. It is not enough to be used as a resin.

[Means for solving problems]

The present invention improves the above-mentioned drawback of the conventional glass transition temperature of a phenol-modified aromatic hydrocarbon formaldehyde resin having a low glass transition temperature, and makes it possible to industrially produce a phenol-modified aromatic hydrocarbon formaldehyde resin having excellent heat resistance. Completed the method.

That is, the present invention is characterized in that an aromatic hydrocarbon formaldehyde resin having a diallylmethane component content of 5% by weight or less and a xylenol number of 15 mol / kg or more is used as the aromatic hydrocarbon formaldehyde resin. .

Here, the "xylenol number" indicates the reactivity with the third component of the aromatic hydrocarbon formaldehyde resin, and the aromatic carbonization when the aromatic hydrocarbon formaldehyde resin and 2,6-xylenol are reacted. It is expressed as the number of moles of 2,6-xylenol reacted with 1 kg of hydrogen formaldehyde resin. Therefore, the higher the "xylenol number", the higher the reactivity.

A phenol-modified aromatic hydrocarbon formaldehyde resin obtained by using such a highly reactive aromatic hydrocarbon formaldehyde resin, a molded article obtained by curing with hexamine, has a glass transition temperature of 240 ° C to 250 ° C. high,
It has a high strength retention rate when heated and is an excellent heat-resistant resin.

The aromatic hydrocarbon formaldehyde resin having a diallylmethane component content of 5% by weight or less and a xylenol value of 15 mol / kg or more used in the present invention has a molar ratio of formaldehyde to aromatic hydrocarbon of 2.0 to 5.0, preferably
2.5 to 3.5, the sulfuric acid concentration in the aqueous layer is 15 to 35% by weight, preferably 20 to 30% by weight, and the reaction temperature is 80 to 110 ° C.
It can be produced by a method in which the reaction rate of formaldehyde is controlled within a range of 50 to 70 mol% and the reaction is performed in about 8 hours. As a method of suppressing the reaction rate of formaldehyde within the above range, one method is to stir at a warm stirring speed that maintains the interface between the water layer and the oil layer (resin layer).

The conventional reactive aromatic hydrocarbon formaldehyde resin generally has a diallylmethane component content of 10 to 15% by weight and a xylenol value of about 10 mol / kg.

The phenol-modified aromatic hydrocarbon formaldehyde resin having excellent heat resistance of the present invention is produced in the same manner as the conventional method for producing a phenol-modified aromatic hydrocarbon formaldehyde resin. That is, it can be obtained by reacting the above-mentioned highly reactive aromatic hydrocarbon formaldehyde resin with phenols in the presence of a catalyst.

The phenols used in the present invention are di- and trifunctional 1
It means a valent or divalent phenolic compound. For example, phenol, cresols, bisphenol propane, bisphenol methane, resorcin, pyrocatechol, hydroquinone, paratertiary butylphenol, bisphenol sulfone, bisphenol ether, paraphenylphenol and the like. Of these, phenol is most suitable for use in applications such as laminates and molded products, but also includes mixtures with other phenols.

The number of moles (P) of the phenols used here is the aromatic hydrocarbon formaldehyde resin calculated from the xylenol equivalent shown below by regarding the aromatic hydrocarbon formaldehyde resin used in the present invention as one formaldehyde. Apparent number of moles obtained based on apparent molecular weight
You can decide based on (F). The F / P molar ratio used is 0.3 to 0.95, preferably 0.6 to 0.9.

The "xylenol equivalent" is the number of grams of the aromatic hydrocarbon formaldehyde resin in which 1 mol of 2,6-xylenol reacts, and the "apparent molecular weight" is obtained by doubling the xylenol equivalent.

The reaction between the highly reactive aromatic hydrocarbon formaldehyde resin and the phenols in the present invention is carried out by using an acid or stannic chloride, zinc chloride, ferric chloride, boron trifluoride in the absence of solvent or in the presence of a high boiling point solvent. It is carried out by adding a Friedel-Crafts type catalyst such as etherate. Of these, the most preferred catalyst is an acid, and the main acid is an organic sulfonic acid such as paratoluenesulfonic acid and xylenesulfonic acid. The amount used cannot be unconditionally limited because it has a correlation with the reaction temperature and time, but it is generally 0.01 to 1.0% by weight based on the total amount charged. The reaction temperature depends on the type and amount of catalyst, but is generally 100 to 200 ° C.
The reaction time is 1 hour to 5 hours.

In the present invention, the solvent may be any solvent having a high boiling point that dissolves the reaction raw material and the produced resin and is insoluble in water, and is used as necessary for smoothly proceeding the reaction and the distillation of the reaction produced water. Is.

The reaction is generally carried out with a thread in excess of phenols, and the oxygen-containing groups such as acetal bond, dimethylene ether bond, methylol group and methoxy group in the aromatic hydrocarbon formaldehyde resin react with the phenols to dehydrate and A methylene bond is formed along with the demethanol reaction. The above reaction is called a one-step reaction. The product obtained by this one-step reaction contains unreacted phenols in addition to the phenol-modified aromatic hydrocarbon formaldehyde resin. The unreacted phenols can be distilled off under reduced pressure in the system, or formaldehyde can be added afterwards to convert the residual phenols into phenol novolac or resole in the presence of a phenol-modified aromatic hydrocarbon formaldehyde resin. .

The post-condensation reaction, in which formaldehyde is post-added and the residual phenols are further condensed, is carried out in the presence of an acid catalyst such as hydrochloric acid or silicic acid, or in the presence of an alkali catalyst, as in the case of producing a usual phenol formaldehyde resin. React to. The reaction is usually performed at 100 to 150 ° C.

The amount of post-addition of formaldehyde is calculated from the number of moles (P) of phenols in the one-step reaction and the number of moles (F) of the aromatic hydrocarbon formaldehyde resin calculated from the apparent molecular weight of the aromatic hydrocarbon formaldehyde resin. Obtain the ratio, with reference to this molar ratio, in the case of acid-catalyzed reaction, the total F / P molar ratio after addition of formaldehyde is 0.7 to 0.95, preferably 0.8.
Decide to be ~ 0.9.

In this post-condensation reaction with formaldehyde, the viscosity of the reaction system increases with the progress of the reaction. Therefore, in order to facilitate stirring and smoothly proceed the reaction, for example, an aromatic hydrocarbon such as toluene / xylene is used. It is preferable to add and react. After completion of the reaction, the temperature is raised to 160 ° C., and volatile components such as water are removed out of the system under reduced pressure and concentrated.

The phenol-modified aromatic hydrocarbon formaldehyde resin produced as described above reacts with a curing agent such as hexamine when heated to give a cured product. Hexamine is added in an amount of 5 to 15% by weight, preferably 8 to 12% by weight, based on the resin. When the application is a laminated board, a predetermined amount of hexamine is added to the produced resin and dissolved in a mixed solvent of an aromatic hydrocarbon such as methyl ethyl ketone or toluene, xylene and a lower alcohol such as methanol, ethanol, butanol, etc.,
Used as a varnish. In the case of a molded product, hexamine, a filler, an additive and the like are added to the produced resin and the mixture is kneaded with a roll to obtain a molding material.

In the case of the above post-condensation reaction, in the presence of an alkali catalyst, in the case of resolization, the total F / P molar ratio after addition of formaldehyde to be added is 1.1 to 3.0, preferably 1.2 to 2.5. Decide to be. In this case, since the produced resin itself has a property of being thermoset, it is preferable to set the temperature of the concentration step to a temperature lower than 130 ° C. This resol-type resin is used as a varnish-like product by adding methyl ethyl ketone or a mixed solvent of an aromatic hydrocarbon and a lower alcohol after concentration.

The varnish produced in this way gives a cured product by heating without adding a curing agent such as hexamine.
From the viewpoint of curing speed, it is preferable to add a small amount of hexamine. Hexamine is added to the resin solids,
It is 10% by weight or less, preferably 8% by weight or less.

〔The invention's effect〕

As described above, the phenol-modified aromatic hydrocarbon formaldehyde resin produced according to the present invention is superior in heat resistance to the phenol-modified aromatic hydrocarbon formaldehyde resin obtained from the conventional ordinary aromatic hydrocarbon formaldehyde resin. By utilizing this heat resistance, it is used in a field requiring particularly heat resistance such as a laminated plate, a molded product, and an insulating varnish.

〔Example〕

 The present invention will be specifically described below with reference to examples and examples.

Reference Example (Production of highly reactive aromatic hydrocarbon formaldehyde resin) 47% formalin 691 parts (10.8 mol) in a 2 condensable flask equipped with a reflux condenser, a thermometer, and a 60-mm anchor-shaped stirring blade. Charge 237 parts of 98% sulfuric acid and 572 parts of meta-xylene (5.4 mol) in this order, stirring speed 200 rpm
Then, the reaction rate of formaldehyde was adjusted to 70% in 7 hours at 98 ° C to 103 ° C under reflux.

Then, 458 parts of diluting metaxylene was added, and the mixture was stirred and allowed to stand to separate an oil layer and an aqueous layer. Wash the oil layer twice with warm water, 13
Stripping was carried out under reduced pressure of 0 ° C./30 mmHg for 1 hour to obtain 700 parts of a pale yellow viscous resin. The produced resin had a dixylylmethane content of 2.5%, a xylenol value of 16.0 moc / kg, a resin molecular weight of 480 measured by a vapor pressure method, and an apparent molecular weight of 125.

Example 1 600 parts of the resin obtained in the reference example (4.80 mol regarded as formaldehyde having an apparent molecular weight of 125), 564 parts of phenol (6.0
(Mole) is charged into a 2 separable flask and uniformly mixed, then 0.5 part of paratoluenesulfonic acid is added as a catalyst and the temperature is gradually raised. Generated water distills out with heat generation from around 90 ° C. The temperature is raised while avoiding sudden heat generation and the end point is reached when no distillate is produced at the maximum temperature of 150 ° C. Unreacted phenol and volatile components are removed by vacuum concentration,
980 parts of a resin having a light brown color and a solid softening point of 96 ° C. at room temperature were obtained. (The softening point was measured by the ring and ball method. The same applies to the following.) Example 2 460 parts of the resin obtained in Reference Example (3.68 mol as an apparent formaldehyde having a molecular weight of 125) and 540 parts (5.74 mol) of phenol were charged into a two-separable flask. 0.3 parts of paratoluenesulfonic acid is added as a catalyst and the temperature is raised while controlling the state of heat generation. The reaction is carried out at 100 to 130 ° C for 1 to 2 hours, and when no water is produced, the content is cooled to 90 ° C or lower. Next, 100 parts of xylene, 88 parts (1.43 mol) of 47% formalin and 5 parts of silicic acid are added, and the temperature is raised again and the reaction is carried out under reflux for 2 hours. After the reaction, the content is concentrated under normal pressure or reduced pressure, and the time point when the maximum temperature reaches 160 ° C is taken as the end point.
923 parts of a light brown solid resin having a softening point of 98 ° C was obtained.

Example 3 460 parts of the resin obtained in Reference Example (3.68 mol as an apparent formaldehyde having a molecular weight of 125) and 540 parts (5.74 mol) of phenol were charged in a two-separable flask and BF was used as a catalyst.
₃ g of O (C ₂ H ₅ ) ₅ is added, and the reaction is carried out at 130 to 180 ° C. for 1 to 2 hours. When the produced water is exhausted, the content is cooled to 90 ° C. or lower. Next, xylene 100 parts, 47% formalin 8
8 parts (1.43 mol) and 5 parts of silicic acid are added, the temperature is raised again, and the reaction is carried out under reflux for 2 hours. After the reaction, the content is concentrated under normal pressure or reduced pressure, and the point when the maximum temperature reaches 160 ° C is set as the end point. 910 parts of a light brown solid resin having a softening point of 97 ° C. was obtained.

Examples 4, 5 and 6 Each resin obtained in Examples 1, 2 and 3 has a diameter of 13 μm and a length of 3 mm.
Glass fiber, hexamine, coal slaked, zinc stearate and a surface treatment agent were blended in the following formulation, mixed and kneaded for a predetermined time with a hot roll, and then crushed and then heated and pressed to make a bending test piece. . The obtained test piece was post-cured by a hot air circulation dryer. Table 1 shows the heat resistance of the molded product. As a comparative example, a commercially available phenol-modified xylene formaldehyde resin having a softening point of 96 ° C. obtained by a conventional method was used and molded in the same manner as described above, and the heat resistance of the test piece subjected to post-curing is also shown in Table- Shown in 1.

The compounding amount, molding conditions, and post-curing conditions are as follows.

The mixing ratio resin 100 parts hexamine 10 parts extinguishing coal 2 parts glass fiber, 50 parts of zinc stearate 3 parts surface treatment agent 0.3 parts hot pressing conditions Temperature 175 ° C. Time 1.5 min / 1 mm thick pressure 200 kg / cm ² after curing conditions 140 ° C. -6 hours 170 ℃ -12 hours 220 ℃ -6 hours 250 ℃ -6 hours

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Publication Sho 55-9013 (JP, B2)

Claims (1)

[Claims] 1. A method for producing a phenol-modified aromatic hydrocarbon formaldehyde resin by reacting an aromatic hydrocarbon formaldehyde resin with phenols, wherein the aromatic hydrocarbon formaldehyde resin is a mole of aromatic hydrocarbon and formaldehyde. The ratio is 2.0-5.0 and the sulfuric acid concentration is
The content of diallyl methane is 5 to 35% by weight, the temperature is 80 to 110 ° C., the reaction rate of formaldehyde is suppressed to the range of 50 to 70 mol% for 4 to 8 hours, and the reaction is conducted.
A method for producing a phenol-modified aromatic hydrocarbon formaldehyde resin characterized by using an aromatic hydrocarbon formaldehyde resin having a xylenol value of 15 mol / kg or more in an amount of not more than 15% by weight.