JP2646464B2 - Thermosetting phenolic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin composition, and more particularly to a thermosetting phenolic resin which is powdery, has a high thermosetting rate and has fluidity when melted by heating, and is suitable as a molding material. Composition.

[0002]

2. Description of the Related Art A thermosetting resin as a molding material is desired to have good fluidity at the time of melting, a high thermosetting rate, and not to generate harmful gas upon heating. Conventionally, and granulated or powdered used in molding Fe
Nol-formaldehyde resin
The thing described in No. 30211 is known.

The above-mentioned powdery phenol / formaldehyde
The resin contains spherical primary particles and secondary agglomerates having a particle size of 0.1 to 150 μm, which are formed from a condensate of phenols and formaldehyde, and has thermosetting properties and good storage stability. And a very low content of free phenol, so that safety during operation is high. In addition, since there is no need to use hexamethylenetetramine as a curing agent unlike novolak, ammonia gas is not generated, and the working environment is deteriorated due to bad smell, or the ammonia gas remaining in the molded product is removed by molding. There is no risk of corroding metals inserted into the product or adjacent metals during use.

However, the powdery phenols disclosed in the above publications
Since formaldehyde resin has a low thermosetting rate, a normal molding temperature (for example, 150
(.About.180 ° C.), there is a problem that the thermosetting time must be lengthened or molded at a higher temperature than usual.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies in view of the above-mentioned circumstances, and as a result, have found that a specific thermosetting phenolic resin in powder form is mixed with an alkaline earth metal hydroxide. By solving the above problems, the present invention has been completed and the present invention has been completed. The object of the present invention is to provide a thermosetting phenolic resin having a high thermosetting rate and a good fluidity during heating and melting. Providing a composition.

[0006]

The object of the present invention is to provide a thermosetting resin composition comprising a powdery thermosetting phenolic resin and an alkaline earth metal hydroxide, wherein the thermosetting resin composition comprises Phenolic resin is composed of spherical primary particles having a particle size of 0.1 to 150 microns and secondary aggregates thereof, and the number of methylol groups per phenol nucleus is 0.2 to
This is achieved by a thermosetting phenolic resin composition characterized in that the number is 0.6.

Examples of the alkaline earth metal hydroxide used in the present invention include hydroxides of alkaline earth metals such as calcium, barium and magnesium. Among them, calcium hydroxide and barium hydroxide are preferred. Is preferred in terms of fast curing at high temperature and stability during melting, and calcium hydroxide is particularly preferred.

The mixing ratio of the alkaline earth metal hydroxide used in the present invention is preferably at least 0.1 part by weight, more preferably from 0.5 to 400 parts by weight, per 100 parts by weight of the thermosetting phenol resin. is there. When the alkaline earth metal hydroxide is excessively blended, the unreacted alkaline earth metal hydroxide can be expected to play a role as a filler, and thus the upper limit is not particularly limited.

The powdery thermosetting phenolic resin used in the present invention is composed of powdery spherical primary particles having a particle size of 0.1 to 150 microns and secondary aggregates thereof. In number. That is, the powdery thermosetting phenol resin used in the present invention has a number of methylol groups of 0.2 to 0.6 per phenol nucleus.

In the present invention, if the number of the methylol groups is less than 0.2, the effect of accelerating the curing reaction by the alkaline earth metal hydroxide cannot be sufficiently obtained. Also,
When the number of methylol groups exceeds 0.6, the melting temperature of the resin increases, and the curing reaction proceeds in an insufficiently melted state, resulting in poor moldability.

The above-mentioned powdery thermosetting phenol resin used in the present invention preferably has a number of methylene bonds per phenol nucleus of about 0.9 to 1.2. The number of methylene bonds is related to the molecular weight of the resin, and the larger the number of methylene bonds, the higher the molecular weight.

In the present invention, the number of methylol groups per phenol nucleus is determined by the following formula from a ¹ H NMR spectrum of acetylated phenol resin. _{That, (S 2 -S 3) /} 2 The number of methylol groups _{= ───────────── (S 1/3)} - (S 2/2) where, S ₁ is, [delta] Peak area with a value of 1.80 to 2.50 ppm (attributed to COCH ₃ ) S ₂ is a peak area with a δ value of 4.65 to 5.07 ppm (attributed to PhCH ₂ OAc, PhCH ₂ OCH ₂ OAc) S ₃ is the peak area (attributable to PhCH ₂ OCH ₂ OAc) where the δ value is 5.07 to 5.40 ppm.

The number of methylene bonds per phenol nucleus is a value determined by the following equation. S _4/2 number of methylene bond _{= ────────────── (S 1/3)} - (S 2/2) where, S ₄ are, [delta] value, 3.00 4 to 10.10 ppm peak area (attributable to PhCH ₂ Ph).

In order to obtain the powdery thermosetting phenol resin used in the present invention, for example, the above-mentioned publication (Japanese Patent Publication No. Sho 62-3)
No. 0211) A powdery phenol / formaldehyde tree comprising spherical primary particles having a particle size of 0.1 to 150 μm and secondary aggregates obtained by the production method described in
A methylol group may be added to the fat .

[0015] The powdery phenol formal described in the above publication
The production method of the aldehyde resin is as follows. (1) The following composition, the concentration of hydrochloric acid (HCl) is 5 to 28% by weight, and the concentration of formaldehyde (HCHO) is 3 to 25% by weight.
And the total concentration of hydrochloric acid and formaldehyde is 15-40.
(2) A bath ratio expressed by the following formula: bath ratio = (weight of hydrochloric acid / formaldehyde bath) / (weight of phenols) is maintained at least 8 or more. (3) contacting the phenols with a hydrochloric acid / formaldehyde bath and contacting the phenols with the bath to form cloudiness after the phenols come into contact with the bath; A production method characterized in that the reaction is carried out so as to be formed and the temperature in the reaction system is maintained at 45 ° C. or lower during the contact.

The powdery ferrite produced by the above method is
The nor-formaldehyde resin generally has a methylol group number of about 0.05 to 0.15 per phenol nucleus, and is commercially available under the trade name Bellpearl S (manufactured by Kanebo). Although it is known, the number of methylol groups is small and not suitable for use in the present invention.

The powdery phenol e obtained by the above method
Lumaldehyde resin usually has a methanol solubility of 20%
As described above, in order to obtain the powdery thermosetting phenol resin used in the present invention, it is preferable to use one having a methanol solubility of 70% or more, which is dissolved in water in the presence of calcium hydroxide or barium hydroxide. By reacting with formaldehyde at a temperature of 40 to 55 ° C. to reduce the number of methylol groups to the phenol nucleus 1 while maintaining the particle size substantially.
Powdered thermosetting phenolic resin increased to 0.2 to 0.6 pieces per piece.

The above-mentioned methanol solubility is a value obtained as follows. That is, about 10 g of a sample is precisely weighed (the weight of the precisely weighed W ₀ ), and this is heat-treated under reflux for 30 minutes in about 500 ml of substantially anhydrous methanol.
After the treatment, the mixture is filtered through a glass filter (No. 3), and the remaining sample of the filter is washed with about 100 ml of methanol on the filter. Subsequently, the filter remaining sample is dried at a temperature of 40 ° C. for 5 hours, its weight (W ₁ ) is precisely weighed, and the methanol solubility is determined by the following equation. Generally, the higher the methanol solubility, the lower the molecular weight tends to be. Methanol solubility (%) = {(W ₀ −W ₁ ) / W ₀ } × 100

The essential point of the present invention is that a powdery thermosetting phenol resin having a large number of methylol groups is mixed with an alkaline earth metal hydroxide. Then, by combining such characteristic configurations, the resin composition of the present invention exhibits a synergistic effect, and has a higher temperature dependency of thermosetting characteristics than a case where each is configured alone, and has a higher temperature. Is extremely fast.

[0020]

The present invention will be described below in detail with reference to examples. still,
Before that, a method for measuring “torque after 2 minutes” and “activation energy” in this specification will be described. "Torque after 2 minutes" is a value related to the thermosetting speed, and "activation energy" is a value related to fluidity during heating and melting. As a result of research, the present inventors have found that after 2 minutes, the torque for removing the cured product from the mold without deformation is 10 kgf.
cm or more, the curing rate has a large temperature dependency, and it has been found that a preferable apparent activation energy for obtaining sufficient flow stability at the time of melting is 40 kJ / mol or more.

<Torque After 2 Minutes> 4 g of the sample powder was formed into a tablet having a diameter of 28 mm under a pressure of 1 t / cm ² , and this was a Curastometer VPS type (trade name, manufactured by Orientec Co., Ltd.) set at a temperature of 180 ° C. Between the upper and lower dies.
A 4 ° sinusoidal vibration was applied, and the stress (torque) generated with the hardening of the sample was detected from the upper die to obtain the hardening characteristics (torque-time curve). The torque (kgf · cm) two minutes after the vibration was applied was read.

<Activation Energy> From the curing characteristics obtained by the above method, a point where the torque increase rate is the largest is selected, a tangent line is drawn at that point, and the inclination is apparently the maximum curing speed (kgf · cm / min). ). The same measurement was performed at temperatures of 160 ° C. and 200 ° C., and the apparent maximum curing rate at each temperature was determined. Measuring temperature 160,
The apparent activation energy (kJ / mol) was calculated from an Arrhenius plot of the apparent maximum curing rate obtained at 180 and 200 ° C.

Example 1 The number of methylol groups per phenol nucleus was 0.13
Pieces of powdered phenol-formaldehyde resin Bellpar S-890 (manufactured by Kanebo, average particle size 10-15 microns,
89.1 g of methanol solubility 90%) and paraform (water
After the solution in the made) 60.0 g and a barium hydroxide octahydrate 18.9g formaldehyde was poured into water 1500 g, was allowed to stir for 3 hours while maintaining the 50 ° C. the reaction, to which 5% hydrochloric acid Was added to the mixture, and the mixture was stirred for 1 hour. The solid matter was separated by filtration, washed with water, and dried to obtain a powdery thermosetting phenol resin.

The obtained powdery thermosetting phenol resin has a number of methylol groups of 0.1 per phenol nucleus.
Forty-four had an average particle size of 10-15 microns. For 100 parts by weight of this powdery thermosetting phenolic resin,
10 parts by weight of calcium hydroxide was added and dry-mixed with a coffee mill to obtain a thermosetting phenol resin composition. The result of the obtained thermosetting phenolic resin composition,
As shown in Table 1.

Examples 2 and 3 In Example 1, the amount of calcium hydroxide mixed with the powdery thermosetting phenol resin was changed to 10 parts by weight, and
A thermosetting phenolic resin composition was obtained in the same manner as in Example 1 except that the amounts were 100 parts by weight and 100 parts by weight. The results of the obtained thermosetting phenol resin composition were as shown in Table 1.

Comparative Example 1 The powdery phenol resin used in Example 1 having 0.13 methylol groups per phenol nucleus was used.
The curing characteristics of only the lumaldehyde resin Bellpearl S-890 were as shown in Table 1.

Comparative Example 2 Only the powdery thermosetting phenol resin obtained in Example 1 and having 0.44 methylol groups per phenol nucleus was obtained without adding the calcium hydroxide added in Example 1. The curing characteristics were as shown in Table 1.

[0028]

[Table 1]

Example 4 A thermosetting phenolic resin composition was obtained in the same manner as in Example 1 except that 10 parts by weight of barium hydroxide was used instead of the calcium hydroxide used in Example 1. The results of the obtained thermosetting phenol resin composition were as shown in Table 2.

[0030]

[Table 2]

Example 5 In Example 1, the amount of barium hydroxide octahydrate used for obtaining the powdery thermosetting phenol resin was 18.9.
g of 9.5 g, and the stirring reaction time was changed to 1 hour instead of 3 hours to obtain a powdery thermosetting phenol resin in the same manner as in Example 1. The obtained powdery thermosetting phenol resin has 0.21 methylol groups per phenol nucleus and an average particle size of 10 to 15 particles.
Micron.

This powdery thermosetting phenolic resin 100
As in Example 1, calcium hydroxide 10
Parts by weight were added and dry-mixed with a coffee mill to obtain a thermosetting phenolic resin composition. The results of the obtained thermosetting phenol resin composition were as shown in Table 3.

Comparative Example 3 Only the powdery thermosetting phenol resin having 0.21 methylol groups per phenol nucleus obtained in Example 5 was obtained without adding the calcium hydroxide added in Example 5. The curing characteristics were as shown in Table 3.

Comparative Example 4 In place of the powdery thermosetting phenol resin used in Example 1, the powdery phenol-formaldehyde of Comparative Example 1 was used.
A thermosetting phenolic resin composition was obtained in the same manner as in Example 1, except that the virgin resin Bellpearl S-890 was used. The result of the obtained thermosetting phenolic resin composition,
As shown in Table 3.

[0035]

[Table 3]

A powdery thermosetting phenol resin was obtained in the same manner as in Example 1 except that the stirring reaction time was changed to 18 hours. The resulting powdery thermosetting phenolic resin had 0.65 methylol groups per phenol nucleus and an average particle size of 10 to 15 microns.

This powdery thermosetting phenolic resin 100
As in Example 1, calcium hydroxide 10
Parts by weight were added and dry-mixed with a coffee mill to obtain a thermosetting phenolic resin composition. The resulting thermosetting phenolic resin composition has a high melting temperature,
It did not melt at a low temperature (for example, 100 ° C.), but began to harden soon after melting as the temperature was raised, and was not suitable as a molding material.

[0038]

The resin composition of the present invention has excellent flow stability at the time of melting and high temperature at a high temperature because a powdery thermosetting phenol resin having a large number of methylol groups and an alkaline earth metal hydroxide are combined. It has a remarkably high thermosetting rate and has favorable characteristics as a molding material, and is therefore extremely suitable for molding materials, particularly for injection molding.

Since the resin composition of the present invention has a remarkably high thermosetting rate at a high temperature and excellent flow stability at the time of melting, it has higher molding efficiency and can shorten the molding cycle than conventional products. Become.

As described above, the thermosetting phenolic resin composition of the present invention solves the problems of the conventional product due to its flow stability upon melting and rapid curing property not found in the conventional product, and has excellent molding properties. It has an effect and is extremely useful industrially.

Claims (1)

(57) [Claims] 1. A thermosetting resin composition comprising a powdered thermosetting phenolic resin and an alkaline earth metal hydroxide, wherein the powdered thermosetting phenolic resin has a particle size of 0.1 to A thermosetting phenol resin composition comprising spherical primary particles of 150 microns and secondary aggregates thereof, wherein the number of methylol groups per phenol nucleus is 0.2 to 0.6.