JPH0546860B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to microspherical flame-retardant solid resol resin particles that have thermal reactivity and excellent storage stability, and a method for producing the same. <Prior art> Resole resin (one-step phenolic resin) is generally produced by combining phenols such as phenol and cresol with aldehydes such as formaldehyde and acetaldehyde in the presence of aqueous ammonia, organic amines, and basic catalysts such as sodium hydroxide. It is a resin obtained by polycondensation. Novolac resins (two-step phenolic resins) usually use a crosslinking agent such as hexamethylenetetramine as a curing agent during heat curing, whereas resol resins contain many methylol groups in their molecules, so it is difficult to use a curing agent. It can be heat-cured alone without using it. As resol resins have extremely high reactivity, they are usually manufactured as a water or methanol solution with a solid content of about 50 to 60%, and are stored as a solution. It was difficult to remove it from the solution as a solid. For this reason, various proposals have been made for the production of stable solid resol resins. For example, in Japanese Patent Publication No. 53-42077, phenols and formaldehyde are mixed with a basic catalyst, and ethylenediamine or the like is used. Gelatin, casein,
A method for producing granular or powdery resol resin by adding and reacting a hydrophilic organic compound such as polyvinyl alcohol is also disclosed in Japanese Patent Application Laid-Open No. 52-141893.
In the publication, phenol, formaldehyde, and a basic catalyst such as ammonia are combined with gum arabic,
A method is disclosed for producing particulate resol resins by emulsion polymerization in the presence of protective colloids such as Gutti rubber, hydroxyalkylguar rubber, or partially hydrolyzed polyvinyl alcohol. However, all of these methods use hydrophilic organic polymer compounds as emulsion stabilizers, and since the resol resins obtained by these methods contain hydrophilic organic polymer compounds, the molded products obtained from them are However, it has the disadvantage that the performance deteriorates and the resin particles are fused together (sintering) during storage. In order to eliminate these drawbacks, JP-A-57-
Publication No. 177011 discloses a method for producing fine particulate solid thermosetting phenolic resin by reacting phenols with a large excess of formaldehyde (8 to 10 times the mole relative to the phenols) under an acidic catalyst. ing. However, resins produced by such methods have the drawbacks of poor flow characteristics, poor moldability, and slow curing speed. <Problems to be Solved by the Invention> In view of the above circumstances, the present inventors have conducted extensive studies on the development of microspherical solid resol resins with excellent properties, and as a result, have developed an emulsion of phenols and aldehydes. By allowing water to substantially coexist with water-soluble inorganic salts during polymerization, emulsion polymerization can be carried out extremely stably, and microspherical solid resol resin particles with excellent resin properties can be produced. He discovered that this could be achieved and filed a patent application (Japanese Patent Application No. 150399-1983). Although the resol resin particles have thermal reactivity and resin properties with excellent storage stability, their flame retardance was somewhat insufficient. <Means for Solving the Problems> In view of the above circumstances, the inventors of the present invention have conducted further intensive studies and found that when emulsion polymerizing phenols and aldehydes,
By coexisting a specific fluorine salt and red phosphorus, emulsion polymerization can be carried out extremely stably, and it also has thermal reactivity and excellent storage stability, as well as improved flame retardancy. The present invention has been completed based on this discovery. That is, the present invention provides flame-retardant microspheres coated with red phosphorus and at least one member selected from the group consisting of calcium fluoride, magnesium fluoride, and strontium fluoride, and having a particle size of 500 μm or less. When reacting phenols and aldehydes in resol resin particles and an aqueous medium in the presence of a basic catalyst, at least one selected from the group consisting of calcium fluoride, magnesium fluoride, and strontium fluoride is added to the reaction system. Part or all of the surface is made of red phosphorus and at least one selected from the group consisting of calcium fluoride, magnesium fluoride, and strontium fluoride. This is a method for producing flame-retardant microspherical resol resin particles that are coated and have a particle size of 500 μm or less. Hereinafter, the present invention will be explained in further detail. The microspherical resol resin particles according to the present invention have the resin surface coated with at least one member selected from the group consisting of calcium fluoride, magnesium fluoride, and strontium fluoride (hereinafter referred to as fluorine salt) and red phosphorus. The implementation thereof will be explained below. FIG. 1 is a scanning electron micrograph (magnification:
300 times), and extremely fine red phosphorus and fluorine salt are deposited on the particle surface, covering the particle surface.
The coating of the particle surface with this fluorine salt and red phosphorus is
As described below, it is formed when fluorine salt and red phosphorus coexist when phenols and aldehydes are reacted in an aqueous medium in the presence of a basic catalyst. A desired coating amount can be obtained by changing the amount and the like as appropriate. The resol resin particles of the present invention coated with the fluorine salt and red phosphorus have a microspherical shape with a particle size of 500 μm or less, as shown in FIG.
That is, unlike conventional powder or granular particles, the resol resin particles of the present invention each have a microspherical shape, and no fusion of the particles is observed. As described above, the reason why the resol resin particles of the present invention have a microspherical shape and no fusion is observed is that the fluorine salt coating formed in the production method described below prevents the fusion of particles during resin production and storage. Thus, the resol resin particles of the present invention having the above structure have improved flame retardancy because red phosphorus is uniformly coated on the surface of each particle, and they are also coated with fluorine salt. It has excellent storage stability and can be stored for more than a year without particle fusion, and since it is a microspherical particle with a particle size of 500 μm or less, it is easy to handle during use such as molding. It's easy. Next, a method for producing the flame-retardant microspherical resol resin particles of the present invention will be explained. First, in the method of the present invention, when phenols and aldehydes are reacted in the presence of a basic catalyst in an aqueous medium, a fluorine salt and red phosphorus are allowed to coexist in the reaction system. The phenols used here include phenol and phenol derivatives, and the phenol derivatives include, for example,
m-alkylphenols, O-alkylphenols, and P-alkylphenols substituted with ~9 alkyl groups, specifically m-cresol, p-
Examples include ter-butylphenol, O-propylphenol, resorcinol, bisphenol A, and halogenated phenol derivatives in which part or all of the hydrogen atoms of the benzene nucleus or alkyl group of these are substituted with chlorine or bromine. One or more types may be used. Note that the phenols are not limited to these, and any other compound containing a phenolic hydroxyl group can be used. Further, examples of the aldehydes used in the present invention include formaldehyde in any form of formalin or paraformaldehyde, and furfural, and the molar ratio of the aldehydes to the phenols is 1 to 2, preferably 1.1 to 1.4. Furthermore, as the basic catalyst used in the method of the present invention, basic catalysts commonly used in the production of resol resins can be used, such as aqueous ammonia, hexamethylenetetramine, and alkyl amines such as dimethylamine, diethyltriamine, and polyethyleneimine. Examples include amines. The molar ratio of these basic catalysts to the phenols is preferably 0.02 to 0.2. The amount of fluorine salt to be added when the phenols and aldehydes are reacted in the presence of a basic catalyst is 0.2 to 0.2 to 0.2 to 1.
It is 3.5wt%. To add fluorine salt,
As mentioned above, the fluorine salt may be added directly, or the fluorine salt may be added during the reaction.
More than one type of water-soluble inorganic salt may be added. That is, for example, in place of fluorine compounds such as calcium, magnesium, and strontium, one of the water-soluble inorganic salts may be sodium fluoride, potassium fluoride,
At least one member selected from the group consisting of ammonium fluoride and calcium, magnesium,
At least one selected from the group consisting of strontium chloride, sulfate, and nitrate may be added to produce calcium, magnesium, and fluorine compounds of strontium during the reaction. Further, the amount of red phosphorus added is preferably 0.1 to 4.9 wt% relative to the phenols. The reaction of the method of the present invention is carried out in an aqueous medium, and in this case, the amount of water charged is such that the solid content of the resin is, for example, 30 to 70 wt%, preferably 50 to 70 wt%.
It is desirable that the content be 60wt%. The reaction was carried out at a temperature increase rate of 0.5 to 1.5°C/min under stirring.
The temperature is gradually increased, preferably at a rate of 0.8 to 1.2°C/min, and the reaction temperature is 70 to 90°C, preferably 83 to 87°C.
℃ for 60-150 minutes, preferably 80-110 minutes. After reacting in this way, the reactants are
Upon cooling below 0.degree. C., a stable aqueous emulsion of the solid resol is obtained. Next, the aqueous emulsion is separated into solid and liquid by a conventional method such as filtration or centrifugation, and then washed and dried to form particles with a particle size of 500 μm or less whose surface is coated with substantially insoluble inorganic salts. Solid microspherical resol resin particles of the present invention are obtained. The method of the present invention can be carried out by either a continuous method or a batch method, but is usually carried out by a batch method. As described above, the resol resin particles obtained by the method of the present invention are smooth, non-fused, microspherical solid particles, and as described above, have excellent flame retardancy and good flow characteristics. Excellent moldability. Further, the microspherical resol resin particles produced by the method of the present invention have good reactivity and a fast gelling rate, can be molded in a short time, and have good performance and quality of molded products. Furthermore, the microspherical resol resin particles obtained by the method of the present invention have a particle size of 500 μm or less, and most of them are 100 μm or less, and have an extremely particle size distribution compared to granular resol resin produced by the conventional method. It is Shaap. The microspherical resol resin particles of the present invention are normally used as a moldable solid resol resin, but
The aqueous emulsion of the solid resol obtained after the above-mentioned reaction can also be used as is for adhesives and the like. Furthermore, the resol resin particles of the present invention can be applied to all fields where ordinary phenolic resins are used, such as laminates and binders, and can be used in combination with phenolic resin fillers such as wood flour and glass fibers. It can also be used in combination or blended with other organic polymers such as polyvinyl formal, nylon, etc. <Examples> Hereinafter, the present invention will be specifically explained using examples. Example 1 200g of phenol was added to the three-necked flask from 1, 37
% formalin, 70 g of water, 18 g of hexamethylenetetramine, and 8.4 g of calcium chloride were added with stirring to form a homogeneous solution. To this solution, 40 g of a 10% solution of sodium fluoride was added under stirring, and 60 g of 10% sodium fluoride solution was added.
The temperature was raised to 85° C. in minutes, and after reacting at the same temperature for 30 minutes, 6 g of red phosphorus was added and the reaction was continued for an additional 60 minutes to obtain a resol resin emulsion. Next, the flask contents were allowed to cool to 30°C,
After adding 0.5 ml of water, the supernatant liquid was removed, and the microspheroidal resin particles in the lower layer were washed with water and air-dried. Next, this is heated under reduced pressure (5 mmHg or less) for 50~
It was dried at 60°C to obtain microspherical resin particles with an average particle size of about 50 μm. (Resin A) Example 2 Micro spherical resin particles with an average particle size of about 100 μm were prepared in the same manner as in Example 1, except that the amount of red phosphorus was changed to 3 g and 5.8 g of potassium fluoride was added instead of sodium fluoride. Obtained. (Resin B) Reference Example 1 Microspherical resol resin particles were produced by the method described in Japanese Patent Application No. 59-150399. In other words, add phenol to the three-necked flask in Step 1.
Add 200 g of 37% formalin, 70 g of water, 18 g of hexamethylenetetramine, and 8.4 g of calcium chloride with stirring to make a homogeneous solution. To this solution, add 40 g of a 10% solution of sodium fluoride under stirring, The temperature was raised to 85° C. for 90 minutes, and the reaction was continued at the same temperature for 90 minutes to obtain an emulsion of microspherical resol resin. Next, the flask contents were allowed to cool to 30°C,
After adding 0.5 ml of water, the supernatant liquid was removed, and the microspheroidal resin particles in the lower layer were washed with water and air-dried. Next, this was heated for 50 minutes under reduced pressure (5 mmHg or less).
After drying at ~60°C, microspherical resin particles with an average particle size of about 50 μm were obtained. (Resin C) Reference Example 2 Resin A obtained in Examples 1 and 2 and Reference Example 1 above,
B and C were each molded into a mold of 127 x 12.7 x 3.2 mm at a mold temperature of 160°C and a pressure of 15 N/ ^mm2 for 10 minutes.
UL (Underwriter's Laboratories, Inc) in the United States
Flammability tests were conducted in accordance with Standard 94. The results are shown in Table 1.

[Table] From Table 1, it is clear that addition of red phosphorus improves flame retardancy. In addition, in order to examine moldability, flow characteristics were measured according to JIS K-6911, and gelation time on a 150°C hot plate was also measured. The results are shown in Table 2.

[Table] From Table 2, the system with the addition of red phosphorus showed good values for both gel time and fluidity properties. From this, it became clear that there was no problem in moldability even in the system to which red phosphorus was added. <Effects of the Invention> As described above, the flame-retardant microspherical resol resin particles of the present invention have excellent flame retardancy and have excellent flame retardancy because their surfaces are coated with fluorine salt and red phosphorus. It has good moldability and excellent storage stability, and can be stored for a long period of time without particles fusing.

[Brief explanation of drawings]

Figure 1 is an electron micrograph (magnification:
300 times).

Claims (1)

[Scope of Claims] 1 Part or all of the surface is coated with at least one member selected from the group consisting of calcium fluoride, magnesium fluoride, and strontium fluoride and red phosphorus, and the particle size is 500 μm. Flame-retardant microspherical resol resin particles characterized by the following: 2. When reacting phenols and aldehydes in an aqueous medium in the presence of a basic catalyst, calcium fluoride, magnesium fluoride,
A group consisting of calcium fluoride, magnesium fluoride, and strontium fluoride, the surface of which is partially or entirely composed of calcium fluoride, magnesium fluoride, and strontium fluoride, characterized in that at least one member selected from the group consisting of strontium fluoride and red phosphorus coexist and react with each other. A method for producing flame-retardant microspherical resol resin particles, characterized in that they are coated with at least one selected species and red phosphorus, and have a particle size of 500 μm or less. 3 At least one selected from the group consisting of calcium fluoride, magnesium fluoride, and strontium fluoride in an amount of 0.2 to 3.5 wt% relative to phenols.
A method for producing flame-retardant microspherical resol resin particles according to claim 2, in which they are coexisting.