JPS5942701B2 - Polypropylene resin composition with enhanced flame retardancy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flame retardant propylene resin composition.

It is known to add one type or a combination of two or more organic or inorganic flame retardants in order to obtain a flame retardant propylene resin composition.

However, in such conventional flame retardation, it is necessary to use large amounts of expensive flame retardants, which inevitably increases the product cost.
Problems such as reduced heat resistance of the product, increased corrosiveness, and reduced molding curvature occurred. Furthermore, attempts have been made to reduce the content of combustible substances by adding inorganic fillers other than flame retardants to these systems, but even these efforts have not been able to significantly reduce the amount of flame retardants. It is also known to make the resin flame retardant by adding a filler that contains a large amount of water and releases water at the combustion temperature. This has the drawback of causing foaming, impairing fluidity and processability, and significantly impairing the appearance of the product. The present inventors have overcome the drawbacks of the conventional methods described above. As a result of extensive research in order to make polypropylene flame retardant easily and inexpensively without deteriorating its physical properties, we have found that polypropylene is made with silica, kaolinite, sericite, organic halogenated flame retardants, and trioxide. It was discovered that the objective could be achieved by blending Annamon, and based on this knowledge, the present invention was completed. That is, according to the present invention, at least one selected from silica and kaolinite
Provided is a flame-retardant resin composition comprising at least 10% by weight of sericite added to a resin composition made of polypropylene mixed with an inorganic filler, an organic halide, and antimony trioxide. Ru.

Compared to conventional polypropylene made flame retardant by adding organic halides and antimony trioxide, the composition of the present invention uses sericite together with specially selected silica and/or kaolinite as an inorganic filler. By adding these inorganic substances, the content of organic halides can be kept at an extremely low value of 4 to 15% by weight, which reduces the cost of the product and prevents the deterioration of the enclosure. Improvements in tune and heat resistance are achieved.

In the composition of the present invention, even if a light filler such as talc, calcium carbonate, calcium sulfite, alumina, or zeolite is used in place of silica or kaolinite, the resulting product will easily burn and melt droplets will easily occur. , the intended purpose is not achieved; these silicas and kaolinites must be used together with sericite.

Sericite is 10% by weight or more in the composition, generally 10~
It is used in a proportion of 50% by weight. If this amount is less than 10% by weight, a product with good flame retardancy cannot be obtained.
In the present invention, this sericite not only has an effect of simply increasing the amount of the composition, but also exhibits an excellent effect of making the composition flame retardant through interaction with the resin, flame retardant, etc. in the composition. The polypropylene-based resin of the present invention is normally used as a living resin. Commercially available polypropylene homopolymers or polypropylene-based copolymers (or polyolefin compositions containing these polymers as components, such as those containing about 5% polyethylene, atactic polypropylene, etc.) may be used. It will be done.

The organic halides used as flame retardants in the present invention include chlorinated or brominated alkanes, olefins,
It includes various substances such as alcohols and aromatic compounds, but in general, those that have a high decomposition temperature (over 200°C) and are solid at room temperature, such as hexabromobenzene and tetrapromobisphenol A, are included. suitable.

According to the present invention, the valley component is melt-kneaded with a heated knife using a kneading means such as a Banbury mixer, and then formed into a sheet and pelletized. By using a continuous kneader, a pellet-like flame retardant composition is obtained, and this composition (1) can be used as it is as various molding materials.

In the composition of the present invention, the polypropylene-based resin is used in an amount of 30% by weight or more, generally 30 to 60% by weight. A range of 4 to 15% by weight of the organic halide is sufficient.

In addition, the total amount of inorganic optical filler consisting of kaolinide, silica, cericide, and antimony trioxide is 30 to 60% by weight, and antimony trioxide (eg, in the range of 2 to 10% by weight in the total composition) is 30 to 60% by weight. Yes, kaolinite and (
Moreover, it is preferable that the total amount of silica and sericite is 20% by weight or more. Next, the present invention will be explained in more detail using examples. Example In a Banbury mixer heated to a casing temperature of 150°C, polypropylene (density 0.929/Cc, metal index 9.0y/10 min), a predetermined amount of an inorganic optical filler, antimony trioxide, and an organic halide are added. The resulting kneaded material was formed into a sheet using a mixing roller, cooled and solidified, and then pelletized using a pelletizer.

The pellets thus obtained were injection molded at a cylinder maximum temperature of 21°C and a mold temperature of 50°C to obtain a length of 127°C.
An injection molded product having a size of m11, a width of 12.7 mm, and a thickness of 3.1 U was obtained.

Next, a combustion test was conducted using this injection molded product.

The combustion test in this case was conducted in accordance with the vertical test method of the UL standard, and the fire source removal ridge, the time until the test piece extinguished, the presence or absence of melt dripping, and if dripping occurred, the time to start dripping was measured. . The results are shown in the table below. The measurement results show that the shorter the extinguishing time and the less melt dripping, the better the flame retardancy. In the following table, the average particle diameters of the inorganic optical fillers used are: sericite: 3.8μ, talc: 5.
5μ, kaolinite; 2.1μ, calcium carbonate; 2μ
, calcium sulfite: 3μ, alumina: 4.5μ, zeolite: 5.2μ, and silica: 3.6μ.

In addition, optical filler A in the table is a mixture of 63% by weight of silica, 24% by weight of kaolinite, and 13% by weight of sericite, and its average particle diameter is 7.3μ. Filler B is 19% by weight of silica. %, kaolinite 42% by weight, sericite 3
9% by weight of the mixture, its average particle size (g) is 2.5μ.
% by weight, a mixture of 52% by weight of sericite, and its average particle size (about 2.0μ).The symbols in the flame retardant in the table indicate the following meanings: HBB; hexabromobenzene, TB
A; Tetrapromubisphenol A, TAIC; Tris-1(2,3-dibromopropyl-1)-isocyanate, CTP; Bisguanidium tetrapromphthalate. Each symbol for resin in the table indicates the following meaning.

PP; polypropylene. EPBC: ethylene/propylene block copolymer, ATPP: atactic polypropylene, HDPE: high density polyethylene. In addition, in the compositions shown in the table, 2 to 4, 16 to 17,
19 to 30 (indicates the product of the present invention, /F6.l./F
65~? 15 and 18 indicate comparative products.

Claims (1)

[Claims] 1. Sericite is added in a proportion of at least 10% by weight to a resin composition made of polypropylene containing at least one inorganic filler selected from silica and kaolinite, an organic halide, and antimony trioxide. A flame-retardant resin composition.