JPH04170447A - Coated red phosphorus frame retardant and its production - Google Patents

Abstract

PURPOSE:To obtain a red phosphorus flame retardant for a synthetic resin improved in flame-retarding effect and the color tone of a molding by coating the surface of a red phosphorus particle with a specified coating material and further coating it with a polyphenylene ether resin. CONSTITUTION:A red phosphorus flame retardant is obtained by further coating the surface of a red phosphorus particle coated with aluminum hydroxide or zinc hydroxide, a red phosphorus particle coated with a thermosetting resin or a red phosphorus particle doubly coated with aluminum hydroxide or zinc hydroxide and a thermosetting resin with a polyphenylene ether resin (obtained by oxidative coupling of a 2,6-disubstituted phenol such as 2,6-dimethylphenol). In this way, a red phosphorus flame retardant for a synthetic resin improved in a flame-retarding effect and the color tone of a molding can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a red phosphorus flame retardant used for flame retardant synthetic resins and a method for producing the same. More specifically, the present invention relates to providing a red phosphorus flame retardant for synthetic resins with improved flame retardant effect and improved color tone of molded products by coating the surface of red phosphorus particles with a polyphenylene ether resin.

[Prior art]

Red phosphorus flame retardants are useful for making synthetic resins flame retardant, and have recently attracted attention as non-halogen flame retardants.

In general, when red phosphorus is left in the air, it undergoes oxidation/reduction disproportionation reactions in the presence of moisture, producing phosphorus oxides or acids on the surface of red phosphorus particles, and at the same time producing toxic phosphorus in the air. Releases hydrogen chloride.

This reaction is accompanied by heat generation, so when large amounts of red phosphorus are stored, internal heat accumulation may cause spontaneous combustion, leading to a major accident. Red phosphorus is also extremely sensitive to heat and friction, and can easily ignite and burn at relatively low temperatures or with a light impact.

Conventionally, methods for stabilizing red phosphorus, which are unstable and involve various risks, include adding a small amount of aluminum hydroxide or magnesium hydroxide to negatively catalytically suppress the oxidation of red phosphorus, and using paraffin. Or coated with wax,
Methods of suppressing contact between red phosphorus and air, methods of mixing hydrogen phosphide absorbers such as activated carbon and copper oxide with red phosphorus powder, and methods of impregnating red phosphorus with large amounts of organic substances such as ε-caprolactam and trioxane. Is there any known method? Furthermore, methods of coating red phosphorus with a thermosetting resin or metal hydroxide, and methods of doubly coating red phosphorus with a metal hydroxide and a thermosetting resin are known.

[Invention or problem to be solved]

However, although these methods are effective to some extent in stabilizing red phosphorus, their flame retardant effect is not sufficient as a flame retardant for synthetic resins, which is originally required, and when mixed with synthetic resins, The color tone of the molded product is poor, and further improvements are required.

[Means of problem solving]

The present invention provides red phosphorus particles coated with aluminum hydroxide or zinc hydroxide, or red phosphorus coated with a thermosetting resin, or red phosphorus coated with aluminum hydroxide or zinc hydroxide and a thermosetting resin. It was discovered that the red phosphorus flame retardant was coated with polyphenylene ether resin on the surface of the red phosphorus flame retardant, which dramatically improved its flame retardant effect as a flame retardant for synthetic resins. be.

The red phosphorus used in the present invention is prepared by mixing yellow phosphorus at 250% in an inert gas.
It is obtained by heating to ~600°C, or the red phosphorus used is almost spherical in shape and has a particle size of 200μ.
m or less is preferable. More preferably, it is 150 μm or less.

Coating as used in the present invention refers to substantially covering the surface of the red phosphorus particle, which is a mother particle, with a coating material such as the polyphenylene ether resin, which is a child particle, and covering the surface of the red phosphorus particle with the polyphenylene ether resin, which is a child particle. It is preferable to completely cover the red phosphorus particles with a coating material such as a resin, or there is no problem even if the surface of the red phosphorus particles is partially exposed.

A typical example of a method for coating red phosphorus particles with a thermosetting resin is to add a synthetic raw material or an initial condensate of the thermosetting resin to an aqueous suspension of red phosphorus, and while stirring, coat the applied resin raw material. A method can be used in which the surface of red phosphorus particles is coated with a small amount of thermosetting resin by treatment under homopolymerization conditions. The synthetic raw material or initial condensate of the thermosetting resin to be applied is one in which the polymerization reaction easily proceeds in a red phosphorus-water suspension, or the initial condensate is emulsified and dispersed in water, and the surface of the red phosphorus particles is Any resin raw material may be used as long as it is uniformly deposited and formed into a film.Usually, phenol-formalin type, urea-formalin type, melamine-formalin type, furfuryl alcohol-formalin type, acetone-formalin type, aniline-formin type are used. It is selected from the group consisting of formalin type and polyhydric alcohol-polybasic acid type.

A method for coating red phosphorus particles with aluminum hydroxide or zinc hydroxide is to add an aqueous solution of a water-soluble salt of aluminum or zinc, such as aluminum sulfate, aluminum chloride, zinc sulfate, or zinc chloride, to an aqueous suspension of red phosphorus. After addition, a method can be used in which aluminum hydroxide or zinc hydroxide is adsorbed onto the red phosphorus particles by neutralization with sodium hydroxide or metathesis with ammonium bicarbonate.

As a method of double-coating red phosphorus particles with aluminum hydroxide or zinc hydroxide and a thermosetting resin, first coat the red phosphorus with aluminum hydroxide or zinc hydroxide using the method described above, and then coat the red phosphorus with the thermosetting resin. Use a method of covering.

The polyphenylene ether resin used in the present invention is obtained by oxidative polymerization of 2,6-disubstituted phenol using various catalysts.

The 2,6-disubstituted phenol used is represented by formula (1) (wherein R3 represents a hydrocarbon group having 1 to 4 carbon atoms, and R2 represents a halogen or a hydrocarbon group having 1 to 4 carbon atoms). 2.6
-dimethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2-ethyl-6-
n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromophenol, 2-methyl-6-itubrobylphenol, 2-methyl-6-n
-Propylphenol, 2-ethyl-6-bromophenol, 2-methyl-6-n-butylphenol, 2.6
Examples thereof include -di-n-propylphenol, 2-ethyl-6-ditetraphenol, and the like. These compounds may be used alone or in combination of two or more. Furthermore, there is no practical problem even if a small amount of sulookresol, metacresol, paracresol, 2,4-dimethylphenol, 2-ethylphenol, 2,3,6-trimethylphenol, etc. is included.

Among these 2,6-disubstituted phenols, especially 2,6-disubstituted phenols
-Dimethylphenol is important.

As a catalyst used for oxidative polymerization, a method using a manganese salt-basic compound-amine catalyst system (Japanese Patent Application Laid-Open No. 57-44
625), a method using a manganese chelate catalyst system (
Japanese Patent Publication No. 59-21895), method using basic cupric salt-diamine-tertiary amine-secondary monoamine-hydrogen bromide catalyst system (Japanese Patent Publication No. 53-30698), cobalt salt-amine catalyst system Method according to (Special Publication Publication No. 42-4673
Publication No.).

Any method may be used to coat the surface of the red phosphorus mother particles with the polyphenylene ether resin as long as the surface of the red phosphorus mother particles can be coated with the polyphenylene ether resin. Examples of coating methods include JP-A-62-83029 and JP-A-62-1406.
A method of coating the surface of the red phosphorus mother particles with polyphenylene ether resin using an impact type impacting means described in each publication No. 36, or a method of suspending the red phosphorus mother particles in an organic solvent solution of polyphenylene ether resin. There is a method of making the red phosphorus mother particles cloudy, adhering an organic solvent solution of polyphenylene ether resin to the surface of the red phosphorus mother particles, and then drying them.

To explain in more detail the method of coating the surface of the red phosphorus base particles with the material such as the polyphenylene ether resin to be coated using the impact type impacting means, the red phosphorus particles that will be the base particles and the above-mentioned red phosphorus particles that will be the child particles will be described in more detail. The mixture is mixed with the coating material and introduced into a device having a closed container (casing) with a large number of protrusions and a rotating plate with a large number of protrusions inside, and the rotating plate is rotated at a speed of 5 to 160 m/sec. It rotates at a circumferential speed of , and a large amount of gas (air or inert gas) is self-circulated. As a result, the powder particles are subjected to the instantaneous impact action many times, so that the child particles are embedded or firmly adhered to the surface of the mother particle, and the surface of the mother particle can be covered with the child particles.

The polyphenylene ether resin used in the present invention is preferably in the form of particles of 50 μm or less when the surface of the red phosphorus mother particles is coated with the polyphenylene ether resin using an impact type impact means. Polyphenylene ether particles of 50 μm or less can be easily obtained by employing a precipitation polymerization method and selecting appropriate polymerization conditions when performing oxidative polymerization.

If the polyphenylene ether particles obtained by the precipitation polymerization method are larger than 50 μm, or if the polyphenylene ether particles obtained by using the solution polymerization method and the methanol reprecipitation method are larger than 50 μm, crush them to 50 μm.
It is preferable to use it in the form of particles with a size of less than m.

When using a method in which red phosphorus mother particles are suspended in an organic solvent solution of polyphenylene ether resin, the organic solvent solution of polyphenylene ether resin is attached to the surface of the red phosphorus mother particles, and then dried, polyphenylene obtained by oxidative polymerization is used. A solution in which ether is dissolved in an organic solvent that can dissolve polyphenylene ether resin is used. Any organic solvent can be used as long as it can dissolve the polyphenylene ether resin; examples of organic solvents that can be used include methylene chloride, chloroform, carbon tetrachloride, 1. Examples include halogenated hydrocarbons such as I', 1-trichloroethane, aromatic halides such as chlorobenzene, dichlorobenzene, and trichlorobenzene, and BTXs such as benzene, toluene, and xylene.

The amount of polyphenylene ether resin coated on the surface of the red phosphorus particles is preferably 2 to 100 parts by weight based on 100 parts by weight of red phosphorus. More preferably, it is 5 to 70 parts by weight.

The red phosphorus flame retardant of the present invention can be applied to most thermosetting resins and thermoplastic resins, and can exhibit dramatic flame retardant effects. Typical applicable thermosetting resins include epoxy resin, phenol resin, and urea resin. Examples include melamine resin.

Typical applicable thermoplastic resins include polyamide, polyester, polycarbonate, polystyrene, A
Examples include BS resin, polyolefin, modified PPE resin, polyoxymethylene, polyacrylate, and thermoplastic polyurethane.

[Example]・Example 1 Average particle size 60 coated with phenol resin as a base particle
μm of red phosphorus (hereinafter referred to as PI) and polyphenylene ether resin with an average particle size of 5 μm as child particles are used as raw materials,
Polyphenylene ether particles were fixedly coated on the surface of the red phosphorus particles using an impact type impact device (Hybridiser NH3-1 model manufactured by Nara Kikai Seisakusho ■). When observed using a scanning electron microscope, it was observed that the surface of the red phosphorus particles was coated with polyphenylene ether particles.

Further, as a result of extracting polyphenylene ether from the particles with chloroform and measuring the weight, it was determined that 22 parts by weight of polyphenylene ether was fixed to 100 parts by weight of red phosphorus. (hereinafter referred to as red phosphorus flame retardant A)
Example 2 The same operation as in Example 1 was performed except that red phosphorus (hereinafter referred to as P2) with an average grain size of 40 μm coated with aluminum hydroxide was used as the base particle. The amount of polyphenylene ether fixed was 19 parts by weight. (hereinafter referred to as red phosphorus flame retardant B)
Example 3 Same procedure as Example 1 except that red phosphorus with an average particle size of 45 μm (hereinafter referred to as P3) double-coated with aluminum hydroxide on the inside and phenol resin on the outside was used as the base particle. I did it. The amount of polyphenylene ether fixed was 15 parts by weight.

(Hereafter referred to as red phosphorus flame retardant C) Example 4 100 g of polyphenylene ether resin was mixed with 1 1 chloroform
．． Red phosphorus with an average particle size of 15 μm was dissolved in 000 g and coated with phenolic resin in this solution (hereinafter referred to as P4).
100. g was suspended and stirred at 50°C for 30 minutes.

After filtration, the particles were air-dried and then dried at 150° C. for 130 minutes under nitrogen to obtain red phosphorus particles whose surfaces were coated with polyphenylene ether resin. Polyphenylene ether was extracted from the particles using chloroform, and the weight was measured. As a result, it was determined that 10 parts by weight of polyphenylene ether was attached to the red phosphorus. (Hereafter referred to as red phosphorus flame retardant) Example 5 The same operation as in Example 4 was performed except that red phosphorus coated with aluminum hydroxide and having an average particle size of 20 μm (hereinafter referred to as P5) was used. The amount of polyphenylene ether attached is 1
It was 2 parts by weight. (Hereafter referred to as red phosphorus flame retardant E) Example 6 Except for using red phosphorus (hereinafter referred to as P6) with an average particle size of 20 μm double coated with aluminum hydroxide on the inside and phenol resin on the outside. The same operation as in Example 4 was performed.

The amount of polyphenylene ether deposited was 12 parts by weight. (Hereafter referred to as red phosphorus flame retardant F) Example 7 Impact-resistant polystyrene (Asahi Kasei Corporation Styron 495
) and 20 parts of the red phosphorus flame retardant A of Example 1 were cross-extruded using a twin-screw extruder. The obtained pellets were molded using an injection molding machine, and the flame retardancy was evaluated according to UL94, and it was found to be ■-〇.

Examples 8 to 12 The same operations as in Example 7 were carried out except that the type and amount of the resin component and red phosphorus flame retardant were changed to those listed in Table-1.
The results described in 1 were obtained.

Comparative Examples 1 to 12 The same operation as in Example 7 was performed except that the type and amount of the resin component and red phosphorus flame retardant were changed to those listed in Table 1.
The results described in 1 were obtained.

Comparative Examples 13 to 17 The same operation as in Example 7 was performed except that the type and amount of the resin component and red phosphorus flame retardant were changed to those listed in Table-2.
The results described in 2 were obtained.

The following margin [Effects of the invention] Red phosphorus coated with aluminum hydroxide or zinc hydroxide, or red phosphorus coated with thermosetting resin,
Or red phosphorus is double coated with aluminum hydroxide or zinc hydroxide and a thermosetting resin, and its surface is coated with polyphenylene ether resin to improve its flame retardant effect and moldability as a flame retardant for synthetic resins. It is possible to provide a red phosphorus flame retardant with improved product color.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] 1. A red phosphorus flame retardant characterized by coating red phosphorus with a thermosetting resin and a polyphenylene ether resin. 2. A red phosphorus flame retardant characterized by coating red phosphorus with aluminum hydroxide or zinc hydroxide and polyphenylene ether resin. 3. Red phosphorus with aluminum hydroxide or zinc hydroxide,
A red phosphorus flame retardant characterized by being coated with a thermosetting resin and a polyphenylene ether resin. 4. The surface of the red phosphorus particles is bombarded with a thermosetting resin and polyphenylene ether resin, or aluminum hydroxide or zinc hydroxide, and polyphenylene ether resin, or aluminum hydroxide or zinc hydroxide, thermosetting resin, and polyphenylene using an impact-type impact means. A method for producing a red phosphorus flame retardant characterized by coating it with an ether resin.