JPH0812805A - Flame-retardant thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition useful for various molded articles without causing evolution of a harmful gas, environmental pollution such as scattering of graphite and deterioration of physical properties by blending a thermoplastic resin with specific amounts of thermally expandable graphite and a (modified) ammonium polyphosphate. CONSTITUTION:This composition is obtained by mixing (A) 100 pts.wt. of a thermoplastic resin such as PP-based resin or PE-based resin with (B) 5-200 pts.wt. of thermally expandable graphite and a (melamine-modified) ammonium polyphosphate to give the objective composition. The thermally expandable graphite of the component B is preferably obtained by treating powder such as natural scaly graphite or pyrolytic graphite with an inorganic acid and a strong oxidizing agent to form a graphite interlaminar compound as a crystallized compound having a laminar structure of carbon and neutralizing the compound with ammonia, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant thermoplastic resin composition containing no halogen-containing compound.

[0002]

2. Description of the Related Art Many of thermoplastic resins are originally resins that easily burn, and in recent years, the performance as flame-retardant materials has been required with the expansion of applications, and flame-retardant treatment is performed by various methods. Has been done. Conventionally, as a method of making a thermoplastic resin flame-retardant, a method of adding a halogen-containing compound has been generally adopted. This method can give a high degree of flame retardancy to a high degree of thermoplastic resin, but it produces a large amount of smoke during processing and combustion, and has problems of corrosiveness to equipment and toxicity to human body. Has become. In particular, in recent years, non-halogen flame retardancy has been strongly demanded in terms of safety.

Under such circumstances, a resin flame retardant such as aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, etc., in which a hydrated metal hydroxide which does not generate a toxic gas during flame retardation is added to a thermoplastic resin. The research on aging has become popular. However, using only these hydrated metal hydroxides, in order to impart sufficient flame retardancy to the flammable thermoplastic resin, it is necessary to add a large amount of hydrated metal hydroxides. As a result, the mechanical strength of the obtained molded product is remarkably lowered, and there is a problem that it cannot be put to practical use.

Further, for example, JP-A-3-41163 and JP-A-3-41164 propose to use thermally expandable graphite alone as a flame retardant, but it is sufficient for a thermoplastic resin. In order to impart flame retardancy, it is still necessary to add a large amount, and there is a problem that a large amount of expanded graphite is scattered during combustion.

Japanese Unexamined Patent Publication (Kokai) No. 62-275138 proposes flame retardation by simultaneously adding thermally expandable graphite and red phosphorus to a thermoplastic resin. There is a problem in that it is expensive and, in order to impart sufficient flame retardancy to the thermoplastic resin, it is necessary to add a large amount.

Japanese Unexamined Patent Publication (Kokai) No. 60-152542 proposes to add flame retardant to a thermoplastic resin by simultaneously adding ammonium polyphosphate and triphenylantimony. In order to impart sufficient flame retardancy, it is still necessary to add a large amount, and if added in a large amount, there is a problem that the physical properties of the obtained molded product are markedly deteriorated.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems, and does not generate harmful gas or scatter substances polluting the working environment, and causes deterioration of physical properties. The present invention has been made for the purpose of providing a thermoplastic resin composition capable of producing a molded article having remarkable flame retardancy without performing the above.

[0008]

The first aspect of the present invention relates to 100 parts by weight of a thermoplastic resin and thermally expandable graphite and ammonium polyphosphate or melamine-modified ammonium polyphosphate.
It is a flame-retardant thermoplastic resin composition containing up to 200 parts by weight.

The thermoplastic resin used in the present invention 1 is not particularly limited, and examples thereof include polypropylene resin, polyethylene resin, poly- (1-) butene resin, polypentene resin, polystyrene resin,
Acrylonitrile-butadiene-styrene resin, polycarbonate resin, etc. are used.

Among them, polypropylene resin is
For example, a propylene homopolymer, a copolymer containing propylene as a main component, or a mixture thereof may be used. Examples of the copolymer include propylene-α-
Examples thereof include olefin copolymers. Examples of the α-olefin include ethylene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-butene, 1-pentene and the like.

The polyethylene resin may be an ethylene homopolymer, a copolymer containing ethylene as a main component, or a mixture thereof. As the copolymer, for example, a copolymer of ethylene and an α-olefin other than ethylene, an ethylene-vinyl acetate copolymer,
Examples thereof include ethylene-ethyl acrylate copolymer.

Examples of the acrylonitrile-butadiene-styrene resin include acrylonitrile, butadiene, a copolymer containing styrene as a main component, a polymer blend thereof, a styrene-acrylonitrile copolymer and an acrylonitrile-butadiene copolymer rubber. And a graft-type polymer obtained by graft-copolymerizing styrene and acrylonitrile in the coexistence of a butadiene rubber latex or a styrene-butadiene rubber latex.

Examples of polystyrene resins include polymers of vinyl aromatic compound monomers such as styrene and α-substituted styrenes such as α-methylstyrene, nucleus-substituted styrenes such as vinyltoluene, and copolymerization therewith. Other possible monomers are, for example, acrylonitrile, acrylic acid or methacrylic acid, their (meth) acrylic acid esters such as methyl or ethyl esters, or graft copolymers obtained by graft polymerization of these.

The thermally expansive graphite used in the present invention 1 is a powder of natural phosphorous graphite, pyrolytic graphite, quiche graphite or the like, an inorganic acid such as concentrated sulfuric acid, nitric acid or selenic acid, and concentrated nitric acid or hydrogen peroxide. It is a crystalline compound in which a graphite intercalation compound is produced by treatment with a strong oxidant such as, and a carbon layered structure is maintained.

The thermally expandable graphite obtained by the acid treatment as described above is preferably neutralized with ammonia, an aliphatic lower amine, an alkali metal compound, an alkaline earth metal compound or the like. Examples of the aliphatic lower amine include monomethylamine, dimethylamine, trimethylamine,
Examples thereof include ethylamine, propylamine and butylamine. Examples of the alkali metal compound and the alkaline earth metal compound include hydroxides, oxides, carbonates, sulfates, organic acid salts and the like of potassium, sodium, calcium, barium, magnesium and the like.

The particle size of the thermally expandable graphite is preferably 20 to 200 mesh. If the particle size is smaller than 200 mesh, the degree of expansion of graphite is small, and as a result, the flame retardancy decreases,
If the desired flame retardancy cannot be obtained and the mesh size is larger than 20 mesh, the expandability is large and it is effective in terms of imparting flame retardancy.
The dispersibility at the time of kneading with the resin is poor, and deterioration of the physical properties of the obtained molded product cannot be avoided.

As the phosphorus compound used in the present invention 1, it is necessary to use ammonium polyphosphate or melamine-modified ammonium polyphosphate. These may be used alone or in combination.

In the present invention 1, the thermal expansion graphite and ammonium polyphosphate or melamine-modified ammonium polyphosphate are added in an amount of 100 parts by weight of the thermoplastic resin.
It is required to be 5 to 200 parts by weight. If the amount added is less than 5 parts by weight, sufficient flame retardancy of the obtained molded product cannot be obtained, and if it exceeds 200 parts by weight, the mechanical properties of the obtained molded product deteriorate significantly and it cannot be used.

In the composition of the present invention 1, if necessary,
Flame retardant aids such as hydrated metal hydroxides may be added. As the hydrated metal hydroxide, for example, aluminum hydroxide,
Examples thereof include magnesium hydroxide, basic magnesium carbonate and dawsonite. The addition amount of hydrated metal hydroxide is
Although it depends on the amount of the main flame retardant added, it is preferably 100 parts by weight or less with respect to 100 parts by weight of the thermoplastic resin. When the content exceeds this range, the molded product obtained has high flame retardancy, but its mechanical strength is lowered and it tends to become unusable.

In the composition of the present invention 1, if necessary,
To the extent that characteristics are not impaired, antioxidants such as phenols, amines, and sulfur, metal damage inhibitors, fillers, antistatic agents, stabilizers, crosslinkers, lubricants, softeners, pigments, etc. are added. Good.

The composition of the present invention 1 is uniformly mixed by mixing the respective components using a kneading device such as a single screw extruder, a twin screw extruder, a Banbury mixer, a kneader mixer and a roll.

In the present invention 2, the mixing ratio of the thermally expansive graphite of the present invention 1 and the ammonium polyphosphate or the melamine-modified ammonium polyphosphate is 1:10 to 10: 1 by weight.
Which is a flame-retardant thermoplastic resin composition.

If the mixing ratio of the heat-expandable graphite is too large, the graphite expands and scatters during the flame-retarding process to contaminate the working environment, and if the mixing ratio of the ammonium polyphosphate or the melamine-modified ammonium polyphosphate is too large. Since it is necessary to add a large amount in order to obtain a molded article having sufficient flame retardancy, the physical properties of the obtained molded article may be deteriorated.

[0024]

The flame-retardant thermoplastic resin composition of the present invention 1 is prepared by adding 5 to 200 parts by weight of thermally expandable graphite and ammonium polyphosphate or melamine-modified ammonium polyphosphate to 100 parts by weight of the thermoplastic resin. As a material for producing molded products with outstanding flame retardance, it does not generate harmful halogen-based gas during combustion or flame-retardant processing and does not scatter graphite that contaminates the work environment. It can be used for various purposes.

The flame-retardant thermoplastic resin composition of the present invention 2 is
Since the mixing ratio of the thermally expansive graphite of the present invention 1 and the ammonium polyphosphate or the melamine-modified ammonium polyphosphate is 1:10 to 10: 1 by weight, the working environment is further polluted as compared with the present invention 1. It can be used for a wide range of applications as a material for producing a molded product having remarkable flame retardancy without causing graphite to scatter.

[0026]

The present invention will be described below with reference to examples. Examples 1 to 6 and Comparative Examples 1 to 6 Each component was melt-kneaded using a Labo Plastomill according to various compounding ratios and molding temperatures as shown in Table 1 and Table 2 to obtain a resin composition. The obtained parts by weight composition was pressed at the molding temperatures shown in Tables 1 and 2 to prepare test pieces. The obtained test pieces were evaluated for flame retardancy.
The results are also shown in Tables 1 and 2.

The flame retardancy is evaluated according to JIS K7201.
A-1 test piece (length x width x thickness = 150 m
The oxygen index was measured with m × 6.5 mm × 3 mm), and those with an oxygen index of 28 or more were marked with ◯, and those with an oxygen index of less than 28 were marked with x.
Regarding the scattering of graphite, the one in which the expanded graphite was not scattered at the time of measuring the oxygen index was marked with ◯, and the one with scattering was marked with x.

Further, as the compounding ingredients in Table 1 and Table 2,
The following contents were used. PP: polypropylene having a density of 0.90 g / cm ³ and a melt index (hereinafter referred to as MI) of 1.5. LDPE: Low-density polyethylene having a density of 0.92 g / cm ³ and MI of 3.4. EVA: vinyl acetate content = 19% by weight, density = 0.92
Ethylene-vinyl acetate copolymer having g / cm ³ and MI = 2.5.

ABS: Density = 1.20 g / cm ³ , MI
= 22 acrylonitrile-butadiene-styrene copolymer. PSt: High-strength polystyrene with a density = 1.06 g / cm ³ and MI = 1.7. Thermally expandable graphite: Nippon Kasei Co., Ltd., trade name "CA-60"
S ". Ammonium polyenoate: Sumitomo Chemical Co., Ltd., trade name "Sumisafe P". Melamine modified ammonium polyphosphate: manufactured by Sumitomo Chemical Co., Ltd.
Product name "Sumisafe PM".

[0030]

[Table 1]

[0031]

[Table 2]

As is clear from Tables 1 and 2, in the cases of Examples 1 to 6 of the present invention, the molded articles obtained were all excellent in flame retardancy and had no graphite scattering. On the other hand, in the case of Comparative Examples 1 to 6, at least one of the fact that a molded article having sufficient flame retardance cannot be obtained, graphite scatters, and brittleness makes it impossible to produce a test piece I have a problem.

[0033]

EFFECTS OF THE INVENTION Since the flame-retardant thermoplastic resin composition of the present invention 1 has the above-mentioned constitution, it produces harmful halogen-based gas during combustion or flame-retardant processing, and reduces the working environment. It can be used for a wide range of applications as a material for producing a molded product having remarkable flame retardancy without scattering contaminating graphite.

The flame-retardant thermoplastic resin composition of the present invention 2 is
Since it is configured as described above, it can be used in a wide range of applications as a material for producing a molded product having remarkable flame retardancy without scattering graphite that further pollutes the working environment as compared with the present invention 1. it can.

Claims (2)

[Claims] 1. A flame-retardant thermoplastic resin comprising 100 parts by weight of a thermoplastic resin and 5 to 200 parts by weight of thermally expandable graphite and ammonium polyphosphate or melamine-modified ammonium polyphosphate. Composition. 2. A flame-retardant thermoplastic resin characterized in that the mixing ratio of the thermally expandable graphite of claim 1 and ammonium polyphosphate or melamine-modified ammonium polyphosphate is 1:10 to 10: 1 by weight. Resin composition.