JPS6136018B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a flame-retardant resin composition with excellent mechanical strength. More specifically, the present invention relates to a resin composition that is made of a specific resin, melamine, and a phosphorus compound, has excellent mechanical strength, does not generate corrosive gas during molding, and exhibits excellent flame retardancy. Conventionally, flame retardant polyolefins have generally been made by adding flame retardants such as organic halogen compounds and flame retardant aids such as antimony trioxide, but highly flame retardant materials without melt dripping have been developed. In order to impart these properties, a considerable amount of these substances must be added, resulting in a significant decrease in the mechanical strength of the resin, especially its impact strength, discoloration due to thermal decomposition during molding, and corrosion due to the generation of corrosive gases. It has many disadvantages, such as corrosion of the mold and a large amount of smoke when burned. On the other hand, adding melamine to thermoplastic resin made it flame retardant.
It is known from No. 1584, but because it uses an extremely large amount of melamine, the mechanical strength, especially the impact strength, is significantly reduced, the fluidity during molding is very poor, and it is difficult to color. It is also possible to add red phosphorus and melamine or polyacrylonitrile to polyolefin to make it flame retardant.
It is known from No. 27461, but it has the disadvantage that it generates hydrogen phosphide during molding, which harms the working environment, and the molded product takes on a dark red color due to red phosphorus, which prevents coloring by colorants. The present inventors have conducted research in order to eliminate the conventional drawbacks and develop a highly flame-retardant resin composition that does not generate corrosive gas during molding, is easy to color, and has excellent mechanical strength. As a result of repeated research, they discovered that it is sufficient to add a specific proportion of melamine and phosphorus compounds to a specific resin. That is, the present invention comprises (A) 30 to 80 parts by weight of one type of homopolymer selected from the group consisting of polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, and polystyrene; and (B) particle size. 60μ
The phosphorus component is 20 to 70 parts by weight of the following melamine and (C) one type of phosphorus compound selected from the group consisting of phosphoric esters, phosphoric acid, metal salts of phosphoric acid, and phosphates or polymers with basic nitrogen-containing compounds. The present invention provides a flame-retardant resin composition with excellent mechanical strength comprising 0.05 to 5 parts by weight. Component (A) used in the present invention constitutes the basic physical properties of the present invention, and specifically includes polyethylene (high-density polyethylene, low-density polyethylene), polypropylene, polybutene-1,
One type of homopolymer selected from the group consisting of poly-4-methylpentene-1 and polystyrene is used. Hereinafter, this component (A) may be simply abbreviated as "resin". Next, melamine, which is component (B), is the main component that imparts flame retardancy to component (A), and is compliant with JIS
- It is acceptable as long as it is of good quality of grade 1 or higher as specified by K1531. The smaller the particle size, the better, and a particle size of 60μ or less is preferable. Such melamine improves the flame resistance and rigidity of the molded article obtained by the present invention, increases the heat distortion temperature, improves mold retention during combustion, and is useful for effectively preventing melt dripping. Contains 20 melamine
If the amount is less than 70 parts by weight, there will be almost no flame resistance and mold retention during combustion, while if it exceeds 70 parts by weight, the impact strength and molding processability of the resulting molded product will decrease, which is undesirable. In the resin composition of the present invention, the phosphorus compound acts synergistically with melamine to exhibit a surprising flame retardant effect. The phosphorus compounds used as component (C) in the present invention include triphenyl phosphate,
Phosphate esters such as octyl diphenyl phosphate, tributyl phosphate, trioctyl phosphate, tricresyl phosphate, dibutylhydrodiene phosphate, phosphoric acid, sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate, zinc phosphate, phosphoric acid Examples include phosphate metal salts such as aluminum, phosphates with basic nitrogen-containing compounds such as guanidine phosphate, guanylurea phosphate, melamine phosphate, triammonium phosphate, triamide phosphate, ammonium polyphosphate, and polyphosphoric acid amide, or their polymers. . These phosphorus compounds are preferably colorless or white and have a Hunter whiteness of 80% or more if they are solid at room temperature so that molded products can be colored as desired. If the amount of the phosphorus compound in the present invention is less than 0.05 parts by weight as a phosphorus component, the flame retardant synergistic effect with melamine will be small, while if it exceeds 5 parts by weight, the impact strength of the molded product will decrease and the melting point will be below the kneading processing temperature. In the case of a phosphorus compound having a phosphorus compound, it is undesirable because it causes deterioration in moldability due to slips and the like. The resin composition of the present invention further includes conventional flame retardants, flame retardant aids, lubricants, plasticizers, dyes, pigments, crystallization promoters, heat stabilizers, ultraviolet absorbers, mold release agents,
In addition to antistatic agents, spreading agents, crosslinking agents, and blowing agents, inorganic fillers such as calcium carbonate, calcium sulfate, calcium sulfite, barium sulfate, talc, kaolin clay, diatomaceous earth, silica, aluminum hydroxide, and magnesium hydroxide agent, wood flour, rice husk,
Cellulosic materials such as straw and pulp, organic fillers such as starch and casein may be optionally blended. Furthermore, for the purpose of improving the mechanical properties of the resin composition, it is also possible to blend various synthetic resins including various rubbers. Although there are no particular limitations on the method of molding the resin composition of the present invention, usually the above-mentioned components are put into a Banbury mixer, intermixer, etc. in a predetermined ratio, melt-kneaded under heat, and then formed into a sheet using a mixing roll. Further, after cooling and solidifying, pelletize with a pelletizer, or after single-screw extrusion of each component, continuously knead with a multi-screw extruder, then perform strand extrusion, and after cooling and solidify, obtain pellets with a strand cutter, Thereafter, it is preferable to process the pellets into molded products by various molding methods such as injection molding, extrusion molding, and blow molding. The molded product obtained in this way has a high degree of flame retardancy and excellent mold retention during combustion, so there is almost no melt dripping, no corrosive gas is generated during molding, and the amount of smoke generated during forced combustion is low. is extremely small,
Any coloring is possible. Furthermore, by incorporating a phosphorus compound, the required amount of melamine can be reduced, so that the decrease in impact strength can be kept to a minimum. Therefore, the resin composition of the present invention can be effectively used in electrical insulating materials, outer shell materials for electrical and electronic products, automobile parts materials, building materials, and the like. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Examples and Comparative Examples Predetermined amounts of resin, melamine, and phosphorus compound were placed in a Banbury mixer heated to a casing temperature of 150°C and kneaded. This kneaded material was then formed into a sheet using a mixing roll, cooled and solidified, and then pelletized using a pelletizer. Maximum cylinder temperature 210℃ using the pellets
℃, injection molded at a mold temperature of 50℃, 5 inches x 1/2
inch x 1/4 inch combustion test piece A, 5 inch x
1/2 inch x 1/8 inch combustion test piece B, 5 inch x 1/2 inch x 1/16 inch combustion test piece C, 5 inch x 1/2 inch x 1/32 inch combustion test piece D A 21/2 inch x 1/2 inch x 1/8 inch impact test piece was obtained and subjected to a flame retardancy test and an impact strength test. The flame retardancy test was conducted based on UL Subject 94 "Flammability Test of Plastic Materials for Equipment Parts" (standard of Underwriters Laboratories, Inc., USA), and the impact strength test was conducted based on the flammability classification. ASTM-D・256
It was conducted without notches in accordance with the "Izotsu Impact Test Method." The results are shown in Table 1. The polypropylene used in the examples and comparative examples had a density of 0.91 g/cm ³ and a melt index of 8 g/cm 3 .
Block copolymer [manufactured by Idemitsu Petrochemical Co., Ltd.: Idemitsu Polypro] for 10 minutes (temperature 230℃, load 2.16Kg)
J750H], polyethylene has a density of 0.967g/cm ³ and a melt index of 6g/10 minutes (temperature 190℃, load
2.16Kg) high-density polyethylene [Idemitsu Petrochemical Co., Ltd.
[Manufactured by Idemitsu Polyethylene 210J], melamine has a weight average particle size of 32μ, and 95% by weight is composed of particles with a particle size of 55μ or less. Furthermore, as for the phosphorus compound that is solid at room temperature, one with a weight average particle size of 30 μm or less was used.

【table】

【table】

【table】

Claims (1)

[Claims] 1 (A) 30 to 80 parts by weight of one type of homopolymer selected from the group consisting of polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, and polystyrene; and (B) melamine with a particle size of 60 μm or less. 20
~70 parts by weight and (C) one type of phosphorus compound selected from the group consisting of phosphoric esters, phosphoric acid, metal salts of phosphoric acid, and phosphates or polymers with basic nitrogen-containing compounds as a phosphorus component of 0.05 to 5 parts by weight. A flame-retardant resin composition with excellent mechanical strength consisting of parts by weight.