JPH0379369B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel allyl etherified cresol novolac or co-condensed novolac resin of cresol and other phenols, and a method for producing the same.

In recent years, resin encapsulation has become mainstream in materials for electrical and electronic parts, particularly semiconductor encapsulation materials, instead of conventional ceramics due to mass productivity and cost considerations.
Novolak-type epoxy resins are mainly used as sealing resins due to their excellent heat resistance and water resistance, but halogens (especially hydrolyzable halogens) cause a decrease in electrical characteristics as the degree of integration increases.
The emergence of high quality resins with low content is strongly desired.

Conventionally known novolac type epoxy resins are obtained by reacting phenolic novolac resins with epihalohydrin, but although they contain almost no inorganic halogens, they contain organic halogens that decompose under high temperature and high humidity. Because it contains around 100 ppm of

In order to solve these problems, the present inventors focused on epoxidation by oxidation of olefin as an epoxidation method that does not use epihalohydrin, and investigated allyl etherified novolak resins as raw materials for epoxidation.

Conventional allyl etherified novolak resins include allyl etherified phenol novolacs, which are disclosed in Kobunshi Kagaku Vol. 22, No. 246; however, since this allyl etherified product contains free phenol hydroxyl groups, When epoxidation is performed by oxidation, the quality of the epoxy resin deteriorates due to oxidation of the phenol skeleton. On the other hand, if the amount of allyl halide used in allyl etherification is increased in order to reduce the content of free phenol hydroxyl groups, the halogen content will increase, making it impossible to achieve the purpose of reducing the halogen content of the epoxy resin.

Under these circumstances, the present inventors conducted intensive studies on allyl etherified products of novolacs, and found that cresol novolacs or co-condensed novolac resins of cresol and other phenols could be allyl etherified under specific reaction conditions. The inventors have found that the allyl etherified product obtained by the method is substantially free of phenol hydroxyl groups and halogens and is suitable for the purpose, and has completed the present invention. That is, the present invention is based on the following formula Allyl etherified cresol novolak or co-condensed novolak resin of cresol and other phenols having the unit shown in When reacting in the presence of an alkaline compound, the phenol hydroxyl group 1 of the novolak resin
There is provided a method for producing the novolak resin, characterized in that 1.05 to 2 moles of allyl halide and 1.05 to 3 moles of an alkaline compound are used based on the equivalent amount.

The novolac resin according to the present invention can be easily converted into an epoxy resin by oxidizing it, and has a phenol hydroxyl group content and a halogen content of less than 1% and 50 ppm, respectively, and substantially contains phenol hydroxyl groups and halogen. Therefore, it is extremely useful as an intermediate for epoxy resins for semiconductor encapsulation.

The present invention will be explained in detail below.

The cresol novolak resin used in the present invention is produced by condensing cresol (o, m, p-isomers) and aldehydes such as formaldehyde, furfural, and acrolein in the presence of an acid or alkali catalyst in a known manner. usually 3 to 15
A novolak resin made from o-cresol and formaldehyde is particularly preferred. In addition, instead of the cresol novolak resin, a co-condensed novolak resin of cresol and other phenols containing other phenols to an extent that does not impair the effects of the present invention (usually 50 mol% or less based on the total phenols); For example, novolac resins cocondensed with monovalent phenols such as phenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, and xylenol, and divalent phenols such as resorcinol, hydroquinone, and catechol can also be used.

Examples of allyl halides used in the present invention include allyl chloride, allyl bromide, and allyl iodide, with allyl bromide being particularly preferred.

The amount of allyl halide to be used is 1.05 to 2 to 1 equivalent of phenol hydroxyl group of the novolak resin.
mol, preferably 1.1 to 1.5 mol. here,
If the amount of allyl halide is less than 1.05 moles, the number of phenol hydroxyl groups in the resulting resin will increase, while if it exceeds 2 moles, the amount of allyl halide that does not directly participate in the reaction will increase, which is industrially disadvantageous. The halogen content increases due to side reactions.

Examples of alkaline compounds used in the present invention include alkali hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and magnesium hydroxide, sodium silicate, sodium aluminate, potassium carbonate, and sodium carbonate. and alkali metal alcoholates such as sodium methylate and sodium ethylate. These are usually used as aqueous or alcoholic solutions. The amount of these alkaline compounds to be used is equimolar to a slight excess of the allyl halide, that is, 1.05 to 3 mol, preferably 1.1 to 2.2 mol, per equivalent of the phenolic hydroxyl group of the novolak resin. If the amount of alkaline compound is less than 1.05 mol, the number of phenol hydroxyl groups in the allyl etherified novolak resin will increase, while if it exceeds 3 mol, the amount of alkaline compound that does not participate in the reaction will increase, which is industrially disadvantageous. be.

For the purpose of adjusting the viscosity of the reaction system, a solvent inert to the reaction, such as acetone, methyl ethyl ketone,
Ketone solvents such as methyl isobutyl ketone, aromatic solvents such as benzene, toluene and xylene, alcohol solvents such as methanol, ethanol, isopropyl alcohol and butanol, and ether solvents such as diethyl ether, tetrahydrofuran and dioxane can be used. Preferably, if the reaction is carried out under an atmosphere of an inert gas such as nitrogen, a resin with a good hue can be obtained.

The allyl etherification reaction of the present invention is usually carried out from 20 to
The reaction is carried out at a temperature of 120°C, preferably 40 to 100°C, and can also be carried out under pressure if the reaction temperature exceeds the boiling point of the reaction system.

After the reaction is carried out until the free phenol hydroxyl groups are substantially disappeared (OH content less than 1%), unreacted allyl halide, if present, is appropriately recovered and the by-product alkali salt is removed. Allyl etherified novolak resin can be obtained.

The allyl etherified novolak resin thus obtained is substantially free of phenol hydroxyl groups and halogens, and therefore is not only useful for electronic and electrical component applications, especially as an intermediate for epoxy resins for semiconductor encapsulation. It is also useful as a polymerizable monomer that takes advantage of double bonds.

EXAMPLES Next, Examples and Reference Examples will be shown to explain the present invention in detail, but the present invention is not limited thereto.

Note that "Example Middle" indicates the weight unit.

Example 1 A reactor equipped with a thermometer, stirrer, dropping funnel and reflux condenser was charged with 118 parts (1 equivalent) of an o-cresol novolak resin with a softening point of 100°C and 200 ml of acetone as a reaction solvent, and the resin was completely dissolved. 306 parts (1.53 mol) of a 20% aqueous sodium hydroxide solution is added, and the mixture is stirred well. While maintaining the temperature of the reaction system at 40°C, 181 parts (1.5 mol) of allyl bromide was added dropwise, and after holding at 40°C for 2 hours, the temperature was raised to 60°C and held at the same temperature for 2 hours. Next, the aqueous layer was removed by separation, diethyl ether was added to the oil layer to extract the resulting resin, and the mixture was concentrated to obtain 160 parts of a pale yellow viscous liquid resin.

As a result of analyzing the obtained resin, the OH content was
0.1%, with a bromine content of 20 ppm or less, the infrared absorption spectrum shows that there is no absorption at 3400 cm ^-1 based on the phenol hydroxyl group, and furthermore, the allylation rate is 112% as determined by the quantitative determination of olefin double bonds in the nuclear magnetic resonance spectrum. - It was confirmed that it was a cresol novolak resin.

Example 2 Yellow viscous liquid resin 155 was prepared in the same manner as in Example 1 except that 133 parts (1.1 mol) of allyl bromide was used.
I got the department.

As a result of analyzing the obtained resin in the same manner as in Example 1, it was found that the OH content was 0.5%, the bromine content was 20 ppm or less, there was almost no absorption of phenol hydroxyl groups in the infrared absorption spectrum, and allyl etherification had an allylation rate of 110%. It was confirmed that it was an o-cresol novolak resin.

Example 3 122 parts (1 equivalent) of o-cresol/2,6-xylenol co-condensed novolak resin (o-cresol content 70 mol%) with a softening point of 100°C and 127 parts (1.05 mol) of allyl bromide were used. Example 1 except that
In exactly the same manner as above, 162 parts of a yellow viscous liquid resin was obtained.

As a result of analyzing the obtained resin in the same manner as in Example 1, it was found that the OH content was 0.2%, the bromine content was 20 ppm or less, there was no absorption of phenol hydroxyl groups in the infrared absorption spectrum, and the allyl etherified o- It was confirmed that it was a cresol/2,6-xylenol co-condensed novolac resin.

Comparative Example A reddish brown viscous liquid resin was prepared in exactly the same manner as in Example 1 except that 121 parts (1 mol) of allyl bromide was used.
Got 150 copies.

The obtained resin was analyzed in the same manner as in Example 1, and it was found that the OH content was 1.5%, the bromine content was 20 ppm or less, there was absorption of phenol hydroxyl groups in the infrared absorption spectrum, and allyl etherification o- had an allylation rate of 98%. It was confirmed that it was cresol novolak resin.

Reference Example: Into a reactor equipped with a thermometer, stirrer, dropping funnel and reflux condenser, 37 parts of the allyl etherified o-cresol novolak resin obtained in Example 1 and 400 ml of dichloroethane as a reaction solvent were charged, and the resin was completely dissolved. Dissolve in. While maintaining the temperature of the reaction system at 50°C, 24% by volume peracetic acid is added dropwise, and after being maintained at the same temperature for 8 hours, it is discharged into water and unreacted peracetic acid is treated with a 10% aqueous sodium sulfite solution. then 1
% sodium hydroxide aqueous solution, washed with water, removed salts, and concentrated to obtain the epoxy equivalent.
41 parts of a reddish-orange semi-solid epoxy resin with a total halogen content of 250 g/ep and 200 ppm or less were obtained.

Claims (1)

[Claims] 1. The following formula Allyl etherified cresol novolac or co-condensed novolac resin of cresol and other phenols (50 mol % or less based on the total phenols) having the unit represented by the formula and having an average number of nuclei of 3 to 15. 2. When reacting cresol novolac or co-condensed novolac resin of cresol with other phenols (50 mol% or less based on total phenols) and allyl halide in the presence of an alkaline compound, the phenol hydroxyl group 1 of the novolac resin is reacted with allyl halide in the presence of an alkaline compound. The following formula is characterized in that 1.05 to 2 mol of allyl halide and 1.05 to 3 mol of alkaline compound are used per equivalent amount. Allyl etherified cresol novolak or co-condensed novolak resin of cresol and other phenols (50 mol% or less based on the total phenols) having the unit shown by and having an average number of nuclei of 3 to 15. Production method.