JPH08113671A - Flame-retardant thermoplastic resin composition - Google Patents

Abstract

PURPOSE: To obtain a lowly smoking and lowly harmful flame-retardant thermoplastic resin compsn. wherein a high level of flame retardancy can be secured without detriment to the properties such as mechanical strength by using a nonhalogen flame retardant. CONSTITUTION: This resin compsn. comprises 100 pts.wt. thermoplastic resin, 2-100 pts.wt. thermally expansible graphite, 0.03-10 pts.wt. metal oxide, 1-150 pts.wt. ammonium polyphosphate, and 1-50 pts.wt. nitrogen compd. of the formula (wherein R<1> to R<3> are each hydrogen, a 1-16C hydroxyalkyl group, a dihydroxyalkyl group, a hydroxyaryl group or a dihydroxyaryl group).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant thermoplastic resin composition capable of obtaining a high degree of flame retardancy.

[0002]

2. Description of the Related Art Thermoplastic resins are widely used for daily sundries, toys, electric devices, building materials, vehicle materials, packaging materials and the like. For these purposes, high flame retardancy is required in terms of fire protection.

To make a thermoplastic resin flame-retardant, generally,
The thermoplastic resin contains a halogen-based flame retardant. Halogen-based flame retardants impart a high degree of flame retardancy to thermoplastic resins,
Although it has the advantage that molding processability and the decrease in mechanical strength of molded products are small, it has the drawback that a large amount of smoke is generated during molding process and combustion, and it is corrosive to equipment and harmful to humans. .

In order to improve the above-mentioned drawbacks of the halogen-based flame retardant, an inorganic flame-retardant such as aluminum hydroxide or magnesium hydroxide, which is a non-halogen flame retardant, and an inorganic powder (such as silicon dioxide or zinc oxide) are used. A flame-retardant resin composition used has been proposed (see JP-A-4-253745).

A flame-retardant resin composition using a hydrous metal compound (such as aluminum hydroxide or magnesium hydroxide) or an alkaline earth metal compound (such as calcium oxide or magnesium oxide) and thermally expandable graphite is also proposed. (See Japanese Patent Laid-Open No. 3-41164).

However, when using an inorganic flame retardant such as aluminum hydroxide or magnesium hydroxide, a high degree of flame retardancy cannot be imparted unless a large amount of flame retardant is used. When a large amount of flame retardant is used as described above, there is a problem that physical properties such as mechanical strength of the molded product are deteriorated. Also, when using thermally expansive graphite, if a large amount of this is used, a high degree of flame retardancy cannot be imparted, and a large amount of expanded graphite will scatter during combustion.

Further, ammonium polyphosphate and tris-
A flame-retardant resin composition containing (2-hydroxy-ethyl) -isocyanurate has also been proposed (JP 63-
61055). However, such a flame-retardant resin composition cannot obtain a high degree of flame retardancy.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and its object is to use a non-halogen flame retardant, to reduce smoke and toxicity, and to reduce physical properties such as mechanical strength. Another object of the present invention is to provide a flame-retardant thermoplastic resin composition capable of preventing the above-mentioned problems and obtaining a high degree of flame retardancy.

[0009]

The above object is to provide 100 parts by weight of a thermoplastic resin, 2 to 100 parts by weight of thermally expandable graphite, 0.03 to 10 parts by weight of a metal oxide, and 1 to 1 part of ammonium polyphosphate. It can be achieved by a flame-retardant thermoplastic resin composition comprising 150 parts by weight and 1 to 50 parts by weight of a nitrogen-containing compound represented by the following general formula (I).

[0010]

Embedded image (In the formula, R ^{1 to} R ³ represent hydrogen or a hydroxyalkyl group having 1 to 16 carbon atoms, a dihydroxyalkyl group, a hydroxyaryl group, or a hydroxyaryl group)

The thermoplastic resin used in the present invention is a known one used in the production of various molded articles such as daily sundries, toys, electric appliances, building materials, vehicle materials, packaging materials, etc., and is not particularly limited. .

For example, polypropylene resin, polyethylene resin, polybutene resin, polypentene resin,
Polystyrene resin, acrylonitrile-butadiene-
Examples thereof include styrene-based resins, polycarbonate-based resins, polyphenylene ether-based resins, polyamide-based resins, acrylic-based resins, and the like, and polyolefin resins such as polypropylene-based resins, polyethylene-based resins, and polybutene-based resins are preferably used.

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

In particular, it is preferable to carry out the acid treatment as described above and then neutralize it with ammonia, an aliphatic lower amine, an alkali metal compound or an alkaline earth metal compound. Here, examples of the aliphatic lower amine include monomethylamine, dimethylamine, trimethylamine, ethylamine, propylamine, butylamine and the like. 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. When the particle size is smaller than 20 mesh, the degree of expansion of graphite is small, and as a result, the flame retardance is lowered. On the contrary, when the particle size is larger than 200 mesh, the degree of expansion of graphite is large and it is good in imparting flame retardancy, When kneaded with the resin, the dispersibility deteriorates and the physical properties of the molded product deteriorate.

Examples of the metal oxide used in the present invention include magnesium oxide, aluminum oxide, titanium oxide, cobalt oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, nickel oxide, zinc oxide and the like. Titanium dioxide is preferred.

The ammonium polyphosphate used in the present invention is represented by the general formula (NH ₄ PO ₃ ) _n and has a degree of polymerization (n)
Is preferably about 100 to 1000 in terms of dispersibility in the resin. As the ammonium polyphosphate, it is possible to use one in which the surface of the powder is coated with a synthetic resin such as a melamine-formaldehyde resin or an epoxy resin to make it water-insoluble and free-flowing.

The nitrogen-containing compound used in the present invention is isocyanuric acid represented by the above general formula (I) or its derivative. Among these, as the derivative of isocyanuric acid,
Mono (hydroxymethyl) isocyanurate, Bis (hydroxymethyl) isocyanurate, Tris (hydroxymethyl) isocyanurate, Mono (dihydroxymethyl) isocyanurate, Bis (dihydroxymethyl) isocyanurate, Tris (dihydroxymethyl) isocyanurate, Mono ( 2-hydroxyethyl) isocyanurate, bis (2-hydroxyethyl) isocyanurate, tris (2-hydroxyethyl) isocyanurate, tris (1,2-hydroxyethyl) isocyanurate, tris (3-hydroxypropyl) isocyanurate, Tris (2,3-dihydroxypropyl) isocyanurate, Tris (4-hydroxybutyl) isocyanurate, Tris (3,4-dihydroxybutyl) isocyanurate, Tris (8-hydroxy-octyl) isocyanurate, tris (4-hydroxyphenyl) isocyanurate, tris (2,4-dihydroxyphenyl) isocyanurate, tris (2,3-dihydroxyphenyl) isocyanurate.

In the present invention, the thermoplastic resin 1
As an additive (flame retardant or flame retardant aid) for imparting flame retardancy to 100 parts by weight, thermally expandable graphite 2 to 10
The use of 0 parts by weight, 0.03 to 10 parts by weight of metal oxide, 1 to 150 parts by weight of ammonium polyphosphate, and 1 to 50 parts by weight of the nitrogen-containing compound represented by the general formula (I) is highly flame retardant. Needed to get. The total amount of these additives is 100 parts by weight of the thermoplastic resin.
It is preferably 5 to 150 parts by weight. If the amount of each of these additives is too small, sufficient flame retardancy cannot be obtained. On the contrary, if the amount of each of these additives is too large, the physical properties such as mechanical strength of the molded product deteriorate.

The thermal expansion graphite, ammonium polyphosphate and the nitrogen-containing compound represented by the general formula (I) are used in such a ratio that the ammonium polyphosphate and the nitrogen-containing compound represented by the general formula (I) are mixed with the metal. It is preferable to use it so that the total amount with the oxide is in the range of 0.1 to 2 with respect to 1 of the thermally expansive graphite, and it is more preferable to use it in the range of 0.5 to 1.5. . If there is too much heat-expandable graphite, the expanded graphite will scatter during combustion, so sufficient flame retardancy cannot be obtained, and conversely ammonium polyphosphate and the nitrogen-containing compound represented by the general formula (I) and the metal oxide will not be obtained. If the amount is too large, the heat-expandable graphite will be insufficient, and the flame retardance will decrease.

The above-mentioned various additives used in the present invention include phenol-based, amine-based, sulfur-based antioxidants, metals and the like as long as they do not affect the physical properties such as mechanical strength of the resin composition. Harm prevention agent, filler, antistatic agent, stabilizer,
A lubricant, a softening agent, a pigment, a cross-linking agent, etc. may be added. Further, a foaming agent may be contained to obtain a foamable flame-retardant resin composition.

The flame-retardant resin composition of the present invention is prepared by mixing a thermoplastic resin and the above-mentioned various additives in appropriate proportions, and melt-kneading the mixture with a kneading device such as a screw extruder, a Banbury mixer, a kneader mixer or a roll. The flame-retardant resin composition can be formed into a desired molded product by various molding devices.

[0023]

As in the present invention, as an additive for imparting flame retardancy to a thermoplastic resin, a thermally expandable graphite, a metal oxide, ammonium polyphosphate and a nitrogen-containing compound represented by the above general formula (I) are contained. When the compound and the compound are contained in an amount within a specific range, the synergistic effect of these additives gives flame retardancy with different flame retardance levels depending on the amount of these additives used, and a relatively small amount. It is possible to obtain a flame-retardant thermoplastic resin composition having a high degree of flame retardancy.

Further, since the above-mentioned various additives are non-halogen flame retardants, they emit less smoke and are less harmful. Further, the expanded graphite is also prevented from scattering during combustion.

[0025]

EXAMPLES Examples and comparative examples of the present invention will be shown below. Examples 1 to 6 and Comparative Examples 1 to 6 As shown in Table 1, various thermoplastic resins, thermally expandable graphite, metal oxides, ammonium polyphosphate and nitrogen-containing compounds were blended, and these were blended with a Labo Plastomill. The flame-retardant resin composition was melt-kneaded and pressed at a molding temperature shown in the table to obtain a plate-shaped body (thickness: 3 mm) of the flame-retardant resin composition.

As the thermoplastic resin, polypropylene (PP) (density 0.90 g / cm ³ , melt index 1.5), low density polyethylene (LDPE)
(Density 0.92 g / cm ³ , melt index 3.
4), ethylene-vinyl acetate copolymer (EVA) (density 0.92 g / cm ³ , melt index 2.5, vinyl acetate content 19% by weight), acrylonitrile-butadiene-styrene copolymer (ABS) (density 1.20 g / cm
³ , melt index 22), polystyrene (PS
t) (density 1.06 g / cm ³ , melt index 1.
7) was used.

Further, the above-mentioned thermally expandable graphite has a particle size of 36.
.About.80 mesh, titanium dioxide is used as the metal oxide, a polymerization degree of 700 or less is used as the ammonium polyphosphate, and tris (2-hydroxyethyl) isocyanurate is used as the nitrogen-containing compound. used.

Using the plate-shaped body of the above flame-retardant resin composition (A-1 test piece: length 150 mm × width 6.5 mm × thickness 3 mm), JIS K7201 (polymer material by oxygen index method) According to the combustion test method), the test was performed by a method of vertically mounting the test piece, and the oxygen index was measured.

Here, an index of high flame retardancy is an oxygen index of 2
A sample having an oxygen index of 28 or more is shown by ◯, and a sample having an oxygen index of less than 28 is shown by x. In addition, ◯ indicates that the expanded graphite did not scatter when measuring the oxygen index, and x indicates that the expanded graphite did scatter. Table 1 shows the results.

[0030]

[Table 1]

[0031]

As described above, the flame-retardant thermoplastic resin composition of the present invention comprises 100 parts by weight of the thermoplastic resin, 2 to 100 parts by weight of the thermally expansive graphite, and 0.03 to 10 parts by weight of the metal oxide. Parts, 1 to 150 parts by weight of ammonium polyphosphate, and 1 to 50 parts by weight of the nitrogen-containing compound represented by the general formula (I), and having a flame retardance level depending on the amount of these various additives used. Different flame retardancy can be obtained, and a high degree of flame retardancy can be obtained by using a relatively small amount, and deterioration of physical properties such as mechanical strength can be suppressed.

Furthermore, since the above-mentioned various additives are non-halogen type, they have the advantages of low smoke emission and low toxicity, and further, graphite that has expanded during combustion does not scatter, and daily miscellaneous goods, toys, electric equipment, building materials, vehicles. It can be suitably used for applications requiring high flame retardancy in terms of fire protection such as materials and packaging materials.

Claims (1)

[Claims] 1. 100 parts by weight of a thermoplastic resin, 2 to 100 parts by weight of thermally expansive graphite, 0.03 to 10 parts by weight of metal oxide, 1 to 150 parts by weight of ammonium polyphosphate, and the following general formula: A flame-retardant thermoplastic resin composition comprising 1 to 50 parts by weight of a nitrogen-containing compound represented by (I). Embedded image (In the formula, R ^{1 to} R ³ represent hydrogen or a hydroxyalkyl group having 1 to 16 carbon atoms, a dihydroxyalkyl group, a hydroxyaryl group, or a hydroxyaryl group)