JPS61235413A - Production of phenol-modified aromatic hydrocarbon/ formaldehyde resin - Google Patents

Abstract

PURPOSE:To obtain a phenol-modified aromatic hydrocarbon/formaldehyde resin excellent in heat resistance and suitable for laminates, etc., by reacting a specified highly reactive aromatic hydrocarbon/formaldehyde resin with a phenol. CONSTITUTION:Formaldehyde is reacted with an aromatic hydrocarbon (e.g., m-xylene) at a molar ratio of about 2-5 in such a manner that they are reacted together at a temperature of about 80-100 deg.C over a period of time of about 4-8hr in an aqueous concentrated sulfuric acid solution of a concentration of about 15-35wt% in a conversion of about 50-70%. In this way, a highly reactive aromatic hydrocarbon/formaldehyde resin having a diallylmethane content <=5wt% and a xylenol value >=15mol/kg can be obtained. This resin is reacted with a phenol (e.g., phenol) to obtain the purpose phenol-modified aromatic hydrocarbon/formaldehyde resin.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for producing a phenol-modified aromatic hydrocarbon formaldehyde resin with excellent heat resistance obtained by reacting an aromatic hydrocarbon formaldehyde resin with phenols. . More specifically, the present invention uses 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 modified aromatic hydrocarbon formaldehyde resin.

[Prior art and its problems]

Phenol-modified aromatic hydrocarbon formaldehyde resin is already well known, and this modified resin is widely used as laminated products, molded products, and coating materials in the electrical and electronic fields, which require better moisture resistance and electrical properties than general-purpose phenol resins. There is.

For example, the known novolac type phenol-modified xylene resin is produced by reacting ordinary xylene formaldehyde resin obtained from meta-xylene and formaldehyde with 7 enols under acidic conditions, and if excess phenol remains, formaldehyde is further added. It is produced by a method such as post-condensation.

The novolak-type phenol-modified xylene resin obtained in this way is thermally cured by hexamine like ordinary phenol novolak, so it is molded together with an inorganic photonic agent such as glass fiber, asbestos, mica, silica, etc. Although molded products formed by heating and pressure molding have excellent long-term heat deterioration resistance, the glass transition temperature of the molded products is not high enough and the strength when heated is low. It is not sufficient for use as a heat-resistant resin.

[Means for solving problems]

The present invention improves the drawback of the low glass transition temperature of the conventional phenol-modified aromatic hydrocarbon formaldehyde resin described above, and provides a method for industrially producing a phenol-modified aromatic hydrocarbon formaldehyde resin with excellent heat resistance at a low cost. completed.

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 value of 15 mol/kg or more is used as the aromatic hydrocarbon formaldehyde resin.

Here, the "xylenol value" indicates the reactivity of the aromatic hydrocarbon formaldehyde resin with the third component. 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 value", the higher the reactivity.

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

The aromatic hydrocarbon formaldehyde resin used in the present invention has a diallylmethane component content of 5% by weight or less and a xylenol value of 15 mol/Y or more, which has a molar ratio of formaldehyde to aromatic hydrocarbon of 2. 0 to 5.0, preferably 2.0 to 3.0, and the sulfuric acid concentration in the aqueous layer is 15
~55% by weight, preferably 20-30% by weight, and 80% by weight.
It can be produced by a reaction method that takes 4 to 8 hours at a reaction temperature of ~110°C and achieves a reaction rate of formaldehyde of 50 to 70%.

In addition, the conventional aromatic hydrocarbon formaldehyde resin having reactivity has a diallylmethane component content of 10 to 1.
Generally, the amount is 5% by weight, and the xylenol value is around 10 mol/kg.

The phenol-modified aromatic hydrocarbon formaldehyde resin of the present invention having excellent heat resistance is produced in the same manner as the conventional method for producing phenol-modified aromatic hydrocarbon formaldehyde resin.

That is, it is obtained by reacting the highly reactive aromatic hydrocarbon formaldehyde resin with phenols in the presence of a catalyst.

The phenols used in the present invention refer to di- and tri-functional monovalent or divalent phenolic compounds. Examples include phenol, flesols, bisphenol propane, bisphenol methane, resorcinol, pyrocatechol, hydroquinone, para-tert-butylphenol, bisphenol sulfone, bisphenol ether, para-phenylphenol, and the like. Among these, YT layer plate,
Phenol is most suitable for use in molded products, but mixtures with other phenols are also included.

The amount of phenols used here is based on the apparent molecular weight of the aromatic hydrocarbon formaldehyde resin calculated from the xylenol equivalent shown below, assuming that the aromatic hydrocarbon formaldehyde resin used in the present invention is oil-soluble formaldehyde. Based on the apparent number of moles obtained based on , the F/P molar ratio is 1.0 to 5.0, preferably 1.1 to 2.0.

In addition, [xylenol, I&J Toha, 2. ! - The number of grams of aromatic hydrocarbon formaldehyde resin with which 1 mole of xylenol reacts, and the "apparent molecular weight" is obtained by doubling the xylenol equivalent.

In the present invention, the reaction between the highly reactive aromatic hydrocarbon formaldehyde resin and the phenol is carried out without a solvent or in the presence of a high boiling point solvent using an acid or stannic chloride, zinc chloride, ferric chloride, boron trifluoride. This is done by adding Friedel-Crafts type catalysts such as etherates. Among these, the most preferred catalyst is an acid, and the main acids are organic sulfonic acids such as para-toluenesulfonic acid and xylenesulfonic acid. The amount used cannot be absolutely limited because it is correlated with the reaction temperature of 9 hours, 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 between 100 and 20
It is 0°C. The reaction time is 1 hour to 5 hours.

In the present invention, the solvent may be any high-boiling point solvent that dissolves the reaction raw materials and produced resin and is insoluble in water, and is used as necessary to smoothly proceed with the reaction and distillation of the reaction product water. It is.

The reaction is generally carried out in a system with an excess of enols, and oxygen-containing groups such as acetal bonds, dimethylene ether bonds, methylol groups, and methoxy groups in the aromatic hydrocarbon formaldehyde resin react with phenols, resulting in dehydration. and a methylene bond is produced with a demethanol reaction.

In the product thus obtained by the polycondensation reaction between the aromatic hydrocarbon formaldehyde resin and the phenols, unreacted phenols are mixed in the phenol-modified aromatic hydrocarbon formaldehyde resin. The unreacted phenols can be distilled off by reducing the pressure in the system, or formaldehyde can be added later, and the remaining phenols can be converted into phenol novolak or resol in the coexistence of a phenol-modified aromatic hydrocarbon formaldehyde resin.

The post-condensation reaction in which formaldehyde is post-added and the remaining phenols are further condensed is carried out in the presence of an acid catalyst such as hydrochloric acid or oxalic acid, or in the presence of an alkali catalyst, as in the production of normal phenol-formaldehyde resins. react to. The reaction is usually carried out at 100-150°C.

The amount of formaldehyde added after is determined by calculating the F/P molar ratio from the number of moles of phenols in the general reaction and the apparent number of moles determined from the apparent molecular weight of the aromatic hydrocarbon formaldehyde resin. With reference to, the total F/P molar ratio after formaldehyde addition is 0.
It is determined to be 75 to 1.20, preferably 0.8 to 0.95.

This post-condensation reaction with formaldehyde is followed by reaction progress I
As a result, the viscosity of the reaction system increases, so in order to facilitate stirring and allow the reaction to proceed smoothly, it is preferable to add an aromatic hydrocarbon such as toluene or xylene to the reaction. After the reaction was completed, the temperature was raised to 160°C,
Volatile components such as water are removed from 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 under heat to give a cured product, regardless of the presence or absence of a post-condensation reaction. The amount of hexamine added is 5 to 15% by weight based on the resin.
, preferably 8 to 12% by weight. If the application is a laminate, add a predetermined amount of hexamine to the resulting resin and dissolve it in a mixed solvent of methyl ethyl ketone or an aromatic hydrocarbon such as toluene or xylene and a lower alcohol such as methanol, ethanol or butanol to form a varnish. used. In the case of molded products, hexamine, fillers, additives, etc. are added to the resulting resin and mixed with rolls to form a molding material.

In the above post-condensation reaction, when the reaction is carried out in the presence of an alkali catalyst to form a resol, the resulting resin itself has the property of thermosetting, so the temperature of the above-mentioned concentration step is 130°C. It is preferable to set the temperature lower than that. After the above concentration, this resol type resin is converted into methyl ethyl ketone,
Alternatively, it is used as a face-like product by adding a mixed solvent of aromatic hydrocarbon and lower alcohol.

The varnish made in this way can be cured by heating without the addition of a curing agent such as hexamine, but it has poor heat resistance and
From the viewpoint of curing speed, it is preferable to add a small amount of hexamine. The amount of hexamine added is based on the resin solid content.
It is 10% by weight or less, preferably 8% by weight or less.

〔Effect of the invention〕

As described above, the phenol-modified aromatic hydrocarbon formaldehyde resin produced by the present invention has superior heat resistance compared to the phenol-modified aromatic hydrocarbon formaldehyde resin obtained from conventional ordinary aromatic hydrocarbon formaldehyde resins. Taking advantage of this heat resistance, it is used in fields that particularly require heat resistance, such as laminates, molded products, and insulating varnishes.

〔Example〕

The present invention will be specifically illustrated by reference examples and examples below.

Reference example (manufacture of highly reactive aromatic hydrocarbon formaldehyde resin) 691 parts (10 parts) of 47% formalin was placed in a 2J3 separable flask equipped with a reflux condenser, a thermometer, and a squid-shaped stirring blade with a width of 60 mm. , 8 mol), 9257 parts of 98% sulfur, and 572 parts (5.4 mol) of meta-xylene were charged in this order, and the mixture was heated at 98°C to 98°C under reflux at a stirring speed of 200 rpm.
It took 7 hours at 103°C to achieve a formaldehyde reaction rate of 70%.

Thereafter, 458 parts of meta-xylene for dilution was added, stirred, and allowed to stand to separate an oil layer and an aqueous layer. Wash the oil layer twice with warm water,
The mixture was subjected to IJ popping for 1 hour under a reduced pressure of 130° C./30 aHf to obtain 700 parts of a pale yellow viscous resin. The resulting resin had a dixylylmethane content of 2.5%, a xylenol value of 16, 0moc/kg, and a resin molecular weight of 480 measured by vapor pressure method, with an apparent molecular weight of 125.

Example 1 600 parts of the resin obtained in the reference example (4.80 moles as formaldehyde with an apparent molecular weight of 125) and 564 parts (6.0 moles) of phenol were added to 2! After charging the mixture into a separable flask and mixing it uniformly, 0.5 parts of para-toluenesulfonic acid was added as a catalyst and the temperature was gradually raised. Produced water begins to distill out with heat generation from around 90°C. The temperature is raised while avoiding rapid heat generation, and the end point is when no distillate is produced at a maximum temperature of 150°C. Unreacted phenol and volatile components were removed by vacuum concentration to obtain 980 parts of a light brown resin that was solid at room temperature and had a softening point of 96°C. (The softening point was measured by the ring and ball method. The same applies hereinafter.) Example 2 460 parts of the resin obtained in the reference example (3.68 mol as formaldehyde with an apparent molecular weight of 125) 540 parts of phenol
(5.74 mol) was placed in a 21 separable flask, 0.3 part of paratoluenesulfone a was added as a catalyst, and the temperature was raised while controlling the exothermic state. 100-130'C
After reacting for 1 to 2 hours, the contents are cooled to below 90°C (when no water is produced).Next, 100 parts of xylene, 88 parts (1°43 mol) of 4796 formalin, and 5 parts of oxalic acid are added. After the reaction, the contents are concentrated under normal pressure or reduced pressure, and the end point is when the maximum temperature reaches 160°C. Softening point: 98
923 parts of a light brown solid resin at a temperature of 923 parts was obtained.

Example 3 460 parts of the resin obtained in Reference Example (3.68 mol as formaldehyde with an apparent molecular weight of 125) Phenol 54
0 parts (5.74 moles) were charged into a separable flask, and BF3.0(C2H5)5 1 fwoE was added as a catalyst.
Afterwards, the reaction is carried out at 130 to 180°C for 1 to 2 hours, and when the produced water is gone, the contents are cooled to below 90°C.

Next, 100 parts of xylene, 88 parts of 47% formalin (1
, 43 mol) and 5 parts of oxalic acid were added thereto, the temperature was raised again, and the reaction was carried out under reflux for 2 hours. After the reaction, the contents are concentrated under normal pressure or reduced pressure, and the end point is when the maximum temperature reaches 160°C. 910 parts of a light brown solid resin with a softening point of 97°C was obtained.

Examples 4 and 5.6 Each of the resins obtained in Examples 1 and 2.5 had a diameter of 13 μm.
A glass fiber of length 3111, hexamine, slaked lime, zinc stearate, and a surface treatment agent were blended and mixed in the following formulation, kneaded for a predetermined time with a hot roll, and after pulverized, a bending test piece was formed by heating and pressure molding. Had made. The obtained test piece was post-cured in a hot air circulation dryer. Table 1 shows the heat resistance strength of the molded product. As a comparative example, the heat resistance strength of a test piece molded in the same manner as above and post-cured using a commercially available 7-enol-modified xylene formaldehyde resin with a softening point of 96°C obtained by a conventional method is also shown. -1.

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

Mixing ratio Resin 100 parts Hexamine 10 parts Slaked lime 2 parts Glass fiber 50 parts Zinc stearate 3 parts Surface treatment agent 03 parts Heat and pressure molding conditions Temperature 175℃ Time: 15 minutes/1a11 thickness Pressure 200~ Post-curing conditions 140'C - 6 hours 170℃-12 hours 220℃-6 hours 250℃-6 hours Procedural amendment (voluntary)

Claims (1)

[Claims] When producing a phenol-modified aromatic hydrocarbon formaldehyde resin by reacting an aromatic hydrocarbon formaldehyde resin with phenols, the aromatic hydrocarbon formaldehyde resin must have a diallylmethane content of 5% by weight or less and a xylenol value. A method for producing a phenol-modified aromatic hydrocarbon formaldehyde resin, characterized by using an aromatic hydrocarbon formaldehyde resin having a content of 15 mol/kg or more.