JPH1160664A - Production on pressure/heat-sensitive self-curing spherical phenolic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin having excellent blocking resistance by condensing a phenol with an aldehyde in the presence of an alkylamine compound catalyst and an emulsifying/dispersing agent being a high-molecular surfactant having glucoside bonds in an aqueous medium. SOLUTION: To a phenol (e.g. resorcinol), an aldehyde (e.g. formaldehyde) in an amount to give a molar ratio to the phenol of 0.6-2.5 is added in an aqueous medium containing at least 30 wt.% water. Next, 0.1-10 wt.%, based on the phenol, high-molecular surfactant having glucoside bonds (e.g. hydroxyethylcellulose/ethylene oxide adduct), 3.0-20.0 wt.%, based on the phenol, alkylamine compound catalyst having at least two aminic hydrogen atoms (e.g. ethylenediamine) and a specified amount of water are added, and the mixture is heated under agitation and reacted under reflex at atmospheric pressure. After the reaction for a definite time, the temperature of the mixture is lowered, and the product is withdrawn, washed and dried to obtain a phenolic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel pressure-sensitive and heat-curable spherical phenol resin used for a wide range of applications such as granular activated carbon, carbon electrodes, grinding wheels, fillers and molding materials.

2. Description of the Related Art Many methods for producing spherical phenolic resins which are easy to handle and have good storage stability have been proposed. As a typical production method, a method of reacting phenols and aldehydes in an aqueous medium in the presence of a hydrophilic protective colloid agent is carried out by reacting a phenol with an aldehyde in the presence of a hexamine catalyst to obtain a condensate. A two-step reaction method in which polyvinyl alcohol is added to react for a longer time to obtain a spherical resin (Japanese Patent Publication No. 53-42077), or phenols and aldehydes in an aqueous medium are protected using a hexamine catalyst, such as gum arabic. A method in which a spherical phenol resin is obtained by reacting in the presence of a colloidal agent (JP-A-52-141893), or a fine phenol is obtained by vigorously stirring using a large excess of formalin with respect to phenol in an acidic catalyst such as hydrochloric acid. A method for obtaining a resin (Japanese Patent Application Laid-Open No. 57-177011) and the like are disclosed.

The method of JP-B-53-42077, which is an example of suspension polymerization using a protective colloid agent, has the disadvantage that it is a two-step reaction and takes a long time as described above. In the reaction using a hexamine catalyst in the presence of a hydrophilic polymer protective colloid agent disclosed in JP-A-52-141893, the hydrophilic polymer protective colloid agent remains in the resin, and the molded article using the same has a reduced strength, poor transparency and poor storage. There is a drawback that blocking at the time, a change with time, and the like are easily caused. However, the method disclosed in Japanese Patent Application Laid-Open No. 57-177011 has the disadvantages that it is difficult to control the particle size, and that a part of the product is agglomerated and the cured product thereof has poor impact resistance. Japanese Patent Application Laid-Open No. 52-141893 discloses a method described in JIS.
It is characterized in that significant values can be obtained in the measurement of gel time (150 ° C.) and plate flow (125 ° C.) specified in K-6910, that is, it flows even when no external force is applied by heating. It is pointed out that in the method, the reaction temperature is optimally from 80 to 85 ° C., and at a temperature higher than 90 ° C., it becomes difficult to control the reaction if the scale of the reaction becomes large. This is because the amine used as a catalyst has a weak catalytic effect, and the reaction system is initially transparent and suddenly becomes opaque when the temperature reaches 85 ° C., and the heat generated in this process is large. In this method, amines other than ammonia and hexamine are described as acting as a plasticizer and causing blocking because amines other than ammonia and hexamine are taken into the resin.Rather, a small amount of ammonia or hexamine is added to carry out the reaction to improve the fluidity of the resin. It can be used as a means. The spherical resin having fluidity by heating obtained in this way is not suitable for applications such as granular activated carbon, a carbon electrode or a single molded plate of only the spherical resin, because the resin particles are fused when heated, The spherical feature cannot be utilized.

Means for Solving the Problems The present inventors have paid attention to such problems and worked diligently to develop a pressure-sensitive heat-curable spherical phenol resin having excellent characteristics, and as a result, have reached the present invention. An object of the present invention is to have a property of containing a methylol group in the molecule and curing only by heat without using a curing agent, and being pressure-sensitive heat self-curing, but curing while maintaining a spherical shape by heating when no external force is applied. It is an object of the present invention to provide a method for producing a pressure-sensitive heat-curable spherical phenol resin having excellent blocking resistance, excellent in blocking resistance without change over time, and excellent in storage stability. Still another object of the present invention is the type and amount of surfactant used,
By selecting the reaction conditions such as the kind and amount of the amine, the molar ratio of the aldehyde to the phenol, and the stirring speed, it is possible to obtain a spherical phenol resin having a particle diameter of several μm to 1 mm, and it is easy to use depending on the application. An object of the present invention is to provide a production method for obtaining a resin. When emulsification suspension condensation of phenols and aldehydes, by selecting a combination of a specific polymer surfactant having a glucoside bond and a limited nitrogen-containing compound catalyst, the desired spherical phenol can be efficiently produced. A resin can be obtained. The resin thus obtained is JIS-K-
No significant measurements are obtained at the gel time (150 ° C.) and plate flow (125 ° C.) as defined in 6910. That is, it does not show fluidity by heating alone, but is thermally fused and hardened when pressure is applied. According to the method of the present invention, the polymer surfactant is not taken into the resin, and the obtained resin does not block during storage. That is, the specific polymer surfactant is limited to at least one selected from the group consisting of hydroxyethylcellulose, hydroxyethylcellulose-2-hydroxypropyltrimethylammonium chloride ether, sodium alginate, and natural rubber metal salts having a mucopolysaccharide skeleton. Examples of the alkylamine compound catalyst containing at least two amino hydrogens as nitrogen-containing compound catalysts include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and N-
By subjecting a phenol and an aldehyde to a normal-pressure reflux reaction in an aqueous medium by using at least one selected from the group consisting of (2-aminoethyl) ethanolamine and N- (2-aminoethyl) propanolamine in combination Pressure-sensitive heat-curable spherical phenolic resin can be obtained. Hereinafter, embodiments of the method of the present invention will be described. The reaction is performed in an aqueous medium containing 30% or more of water in the system. That is, a phenol, an aldehyde, a polymer surfactant, an alkylamine-based catalyst and water are charged into a reactor at a time, and the temperature is increased while stirring, and the mixture is reacted under a normal pressure reflux for a predetermined time. The reaction system is initially opaque.
After a lapse of a predetermined time, water for washing a polymer surfactant is added to lower the temperature of the system to 50 ° C or lower. Thereafter, the resin is taken out using, for example, Nutsche. The obtained resin is washed several times with water until the washing water no longer shows color with the anthrone reagent. After drying for a while, heat dry. Industrially, it is efficient to use a Nutsche filter or a plate dryer. Examples of phenols used in the present invention include phenol, o-, m-, p-cresol, bisphenol A,
One or a mixture of two or more known phenol derivatives such as styrenated phenol, alkylphenol substituted with an alkyl group having 2 to 9 carbon atoms, p-phenylphenol, xylenol, resorcinol, catechol, and pyrogallol can be used. When using a p-substituted phenol, it is preferable to use it together with other phenols. The aldehyde used in the present invention is one or two of formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, terephthalaldehyde, hydroxybenzaldehyde, furfural and the like.
Mixtures of more than one species are mentioned, but formaldehyde and paraformaldehyde are particularly preferred. The molar ratio of aldehydes to phenols is 0.6 to 2.5, preferably 1.1 to 1.8. Examples of the alkylamine compound catalyst containing at least two amino hydrogens used in the present invention include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N- (2-aminoethyl) ethanolamine and N- (2-aminoethyl) ethanolamine. One or a mixture of two or more of-(2-aminoethyl) propanolamine, guanamine, and dicyandiamide is included. The use amount of these alkylamine compound catalysts with respect to phenols is 3.0 to 20.0 wt%, preferably 6.0 to 1%.
5.0 wt%. Examples of the polymeric surfactant having a glucoside bond used in the present invention include hydroxyethylcellulose, hydroxyethylcellulose 2-hydroxypropyltrimethylammonium chloride ether added with 1.4 to 3.5 mol of ethylene oxide per glucose unit, and metal salts of alginic acid. And one or more mixtures of natural rubber metal salts having a mucopolysaccharide skeleton. Since these surfactants are polymerized, they swell in water but hardly dissolve.
It is desirable to adjust the concentration solution. The amount of the surfactant used for the phenols is 0.1 to 10.0 wt%,
Preferably it is 0.5 to 7.0 wt%.

The present invention will be described in more detail by way of examples. [Example 1] A 5-liter flask equipped with a condenser, a thermometer, and a stirrer was charged with 1100 g of phenol, 793.1 g of 50% aqueous formaldehyde, 99 g of triethylenetetramine, 550 g of an aqueous solution in which 11 g of hydroxyethylcellulose was previously dissolved, and 660 g of water. The reaction was carried out under normal pressure reflux for 3.0 hours. Cool to 50 ° C or less, and add water 1
150 g was added, the resin was filtered off with Nutsche, and the surfactant was removed by washing with water. Further, washing with 2500 g of water was repeated 5 times until the filtrate did not show any color with the anthrone reagent. Resin is air-dried and then heated in a hot-air circulation oven.
C. for 1 hour to obtain a spherical resin having an average particle size of 132 .mu.m. The average particle size is Microtrack (Nikkiso 9320X)
-100). Example 2 A 5-liter flask equipped with a condenser, a thermometer, and a stirrer was charged with 1100 g of phenol, 1262.5 g of 50% aqueous formaldehyde, 88 g of pentaethylenehexamine, 400 g of an aqueous solution in which 8 g of sodium alginate was previously dissolved, and 810 g of water. The reaction was carried out under normal pressure reflux for 1.5 hours. Example 1
A spherical resin having an average particle size of 215 μm was obtained in the same manner as in the above. Example 3 1100 g of phenol, 1262.5 g of 50% aqueous formaldehyde, 110 g of N- (2-aminoethyl) ethanolamine and 110 g of hydroxyethylcellulose-2-hydroxypropyltrimethylammonium were placed in a 5-liter flask equipped with a condenser, a thermometer and a stirrer. 550 g of an aqueous solution in which 11 g of chloride ether was dissolved, and 660 g of water were charged and reacted under normal pressure reflux for 2.0 hours. After cooling to 50 ° C. or lower, a spherical resin having an average particle diameter of 74 μm was obtained in the same manner as in Example 1. Comparative Example 1 A spherical phenol resin was synthesized according to the method described in JP-A-53-42077. That is,
500 g of phenol and 318 g of 50% formaldehyde were charged into a 3 liter flask equipped with a condenser, a thermometer and a stirrer, and 50 g of hexamethylenetetramine was added with stirring, and the mixture was heated to 90 ° C. and reacted for 100 minutes. Subsequently, 100 g of 5% polyvinyl alcohol (polymerization degree 1800, saponification degree 88%) was added, the temperature was cooled to 80 ° C., and the reaction was carried out for 240 minutes. After cooling and standing, the supernatant was removed and the spheroidized resin in the lower layer was taken out. The resin was air-dried and dried in a hot-air circulating oven at 100 ° C. for 1 hour to obtain a resin having a particle diameter of about 1 mm. Comparative Example 2 A spherical phenol resin was synthesized according to the method described in JP-A-52-141893. That is, 700 g of phenol, 504 g of 50% formaldehyde, 1020 g of water, 63 g of hexamethylenetetramine, and 7 g of gum arabic were charged into a 3 liter flask equipped with a condenser, a thermometer, and a stirrer, and stirred.
The temperature was raised to 85 ° C. in 5 minutes. The reaction was performed at the same temperature for 1 hour.
The reaction product was washed with water and air-dried in the same manner as in Example 1 and then dried in a hot-air circulating oven at 60 ° C. for 2 hours to obtain an average particle size of 252.
A μm spherical resin was obtained. Examples 1 to 3, Comparative Examples 1 and 2
The following evaluation was performed about the spherical resin obtained by. Table 1 shows the results. -Gel time: Hot plate method (150 ° C) JIS-K-6910 4.8-Plate flow: Glass plate (125 ° C) JIS-K-6910 4.7-Aggregate: Visual judgment on Nutsche-Anthrone reaction: Sample preparation: 10 g of the resin was taken in 40 ml of water and extracted for 1 hour under reflux to prepare a sample. Procedure: Take a 0.1% anthrone concentrated sulfuric acid solution (about 0.5 ml) in a micro test tube, gently add a sample solution (about 1 mg) with a dropper, mix the two solutions, and give a green-blue color. Is positive. -Blocking test Device: (1) Flat plate: 150 mm x 150 mm x 5 mm (2) Cylindrical container: 71 mm x 120 mm (3) Weight: 70 mm x 160 mm, total weight 5 kg (4) Wire mesh: 10 mesh (5) Constant temperature and humidity device : Set to 25 ° C, 65% Operation: Place the cylindrical container on a flat plate and put it in a thermo-hygrostat with a weight. Place 500 g of the sample in a cylindrical container, place a weight on it, and return to the thermo-hygrostat. One hour later, the sample in the cylindrical container was gently taken out on a piece of paper, sieved through a 10-mesh wire gauze and the weight of the sieved block was weighed to calculate the ratio (%) to the original weight. Preparation of a single plate: A plate was prepared by charging 5 g of resin into a mold (60 mm × 28 mm × 1.8 mm) and compression molding (180 ° C. × 5 minutes × 105 kgf / cm ² ). Rockwell surface hardness and bending strength (JIS-K-6911) of the obtained plate were measured.

[Table 1] As can be seen from Table 1, the resins obtained in Examples 1 to 3 had a gel time (150 ° C.) and a plate flow (120 ° C.)
It does not have fluidity when heated, has excellent blocking resistance, and has excellent Rockwell surface hardness and bending strength. Example 4 A spherical resin having an average particle size of 45 μm was obtained in the same manner as in Example 1 except that the polymer surfactant was changed to hydroxyethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether. . Example 5 A spherical resin having an average particle size of 123 μm was obtained in the same manner as in Example 1 except that the polymer surfactant was changed to sodium alginate. Example 6 A spherical resin having an average particle diameter of 15 μm was obtained in the same manner as in Example 3, except that 110 g of N- (2-aminoethyl) ethanolamine was changed to 99 g of tetraethylenepentamine. Example 7 A spherical resin having an average particle size of 2 μm was obtained in the same manner as in Example 6, except that 55 g of hydroxyethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether was used. Example 8 A spherical resin having an average particle diameter of 2 μm was obtained in the same manner as in Example 6, except that 77 g of hydroxyethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether was used. Example 9 Example 6 was the same as Example 6 except that the amount of hydroxyethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether was changed to 110 g.
In the same manner as in the above, a spherical resin having an average particle size of 1 μm was obtained. Example 10 A spherical resin having an average particle size of 42 μm was obtained in the same manner as in Example 6, except that 1492 g of 50% aqueous formaldehyde was used. [Example 11] A spherical resin having an average particle size of 2 µm was obtained in the same manner as in Example 10, except that hydroxyethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether was used in an amount of 55 g. [Example 12] A spherical resin having an average particle diameter of 2 µm was obtained in the same manner as in Example 10, except that 77 g of hydroxyethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether was used. Example 13 A spherical resin having an average particle size of 1 μm was obtained in the same manner as in Example 10 except that hydroxygethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether was changed to 110 g. Example 14 A spherical resin having an average particle size of 45 μm was obtained in the same manner as in Example 6, except that the amount of 50% aqueous formaldehyde was changed to 2061.8 g. [Example 15] A spherical resin having an average particle size of 3 µm was obtained in the same manner as in Example 14, except that hydroxyethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether was used in an amount of 55 g. Example 16 A spherical resin having an average particle diameter of 6 μm was obtained in the same manner as in Example 14, except that 77 g of hydroxyethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether was used. [Example 17] A spherical resin having an average particle size of 2 µm was obtained in the same manner as in Example 14, except that hydroxygethyl cellulose-2-hydroxypropyltrimethylammonium chloride ether was changed to 110 g.

The pressure-sensitive heat-curable spherical phenolic resin obtained by the production method of the present invention has a gelation time (150).
℃), plate flow (120 ℃), and has no fluidity when heated, but it can be melt-hardened by heating and compression molding to form a molded product. It can exert its features in application fields such as refractory binders and molding materials.

Claims (7)

[Claims] A phenol and an aldehyde are subjected to a condensation reaction in an aqueous medium using an alkylamine compound catalyst containing at least two amino hydrogens in the presence of a polymeric surfactant having a glucoside bond as an emulsifying dispersant. A method for producing a pressure-sensitive heat-curable spherical phenolic resin, comprising: 2. The condensation reaction between phenols and aldehydes, wherein the aldehydes are added to the phenols in an amount of 0.6 to 2.
2. The method for producing a pressure-sensitive heat-curable spherical phenolic resin according to claim 1, wherein the amount is in the range of 2.5 mol. 3. The alkylamine compound catalyst containing at least two amino hydrogens in the condensation reaction between the phenols and the aldehydes is used in an amount of 3.
The method for producing a pressure-sensitive heat-curable spherical phenolic resin according to claim 1 or 2, wherein the content is in the range of 0 to 20.0 wt%. 4. The alkylamine compound containing at least two amino hydrogens includes ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-
4. One or a mixture of two or more selected from the group consisting of (2-aminoethyl) ethanolamine and N- (2-aminoethyl) propanolamine. The method for producing a pressure-sensitive heat-curable spherical phenolic resin described in the above item. 5. The high molecular surfactant having a glucosidic bond in the condensation reaction between the phenol and the aldehyde is in the range of 0.1 to 10.0 wt% based on the phenol. A method for producing the pressure-sensitive heat-curable spherical phenolic resin according to any one of claims 1 to 4. 6. The high molecular surfactant having a glucosidic bond in the condensation reaction between the phenols and the aldehydes comprises 1.4 to 3.5 ethylene oxide per glucose unit.
One or a mixture of two or more selected from the group consisting of hydroxyethylcellulose, hydroxyethylcellulose-2-hydroxypropyltrimethylammonium chloride ether, a metal salt of alginic acid, and a natural rubber metal salt of a mucopolysaccharide skeleton to which a mole has been added. The method for producing a pressure-sensitive heat-curable spherical phenol resin according to any one of claims 1 to 5, characterized in that: 7. The pressure-sensitive thermosetting thermosetting composition according to claim 1, wherein the condensation reaction between the phenols and the aldehydes is carried out under normal pressure reflux. A method for producing a spherical phenolic resin.