JPH07252388A - Flame-retardant resin composition - Google Patents

Abstract

PURPOSE:To obtain a nonhalogenous flame-retardant resin compsn. which is excellent in mechanical strengths, elongation, and heat resistance, is inexpensive, and has a producibility (moldability) similar to that of PVC used now. CONSTITUTION:This flame-retardant resin compsn. comprises 20-60wt.% polypropylene resin (a), 1-20wt.% polyethylene modified with an unsatd. carboxylic acid or its deriv. (b), 35-65wt.% metal hydrate (c), and an ethylene copolymer (d) in an amt. satisfying the relation: 0.48>(d)/(a)+(b)+(d) (by wt.).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to mechanical properties, heat resistance,
The present invention also relates to a flame-retardant resin composition having flexibility and excellent extrusion processability, which is suitable for extrusion molding of tubes, pipes, coatings and the like.

[0002]

2. Description of the Related Art Conventionally, P has been used as a flame-retardant resin composition.
A flame-retardant resin composition in which a halogen-based flame retardant is mixed with VC or polyolefin is mainly used. However, such a composition has a problem that a large amount of smoke and corrosive gas such as hydrogen chloride are generated during combustion. Therefore, in recent years,
As a flame-retardant resin composition that does not generate corrosive gas during combustion and generates little smoke, research has been conducted on non-halogen flame-retardant resin compositions that are highly filled with metal hydrates such as magnesium hydroxide. It has been promoted and has been put to practical use in some areas. Since such a composition needs to be highly filled with a metal hydrate, an ethylene / vinyl acetate copolymer or an ethylene / acrylic acid ester copolymer in which a filler such as magnesium hydroxide can be easily added to the base polymer is used. Mainly used. However, the tensile strength of such a composition is about 10 MPa, and the melting point is about 100 ° C.
At present, the characteristic level is still low compared to the characteristics of PVC (tensile strength, about 15 to 20 MPa, heat deformation rate at 120 ° C, about 10%) that is mainly used for extrusion molding applications, and characteristics comparable to those of current PVC. The development of a non-halogen flame-retardant resin composition having the above-mentioned properties is desired. In order to solve such a problem, an example in which a polypropylene resin having excellent mechanical strength and heat resistance is used as a base polymer and a filler is used in a high filling amount has been studied (Japanese Patent Laid-Open No. 62-131052). However, such a composition has a poor extrusion moldability and a poor productivity per unit time in the molding of tubes, pipes and the like.
When an insulated wire is manufactured, it can be manufactured only at a speed of about 10 to 80 m / min, which is extremely low as compared with the coating speed of 400 to 500 m / min required in commercial production. You can see from that.

[0003]

The object of the present invention is to provide a non-halogen compound which is excellent in mechanical strength, elongation, heat resistance, and is inexpensive and has productivity (molding processability) equivalent to that of PVC and the like currently used. It is to provide a flame-retardant resin composition.

[0004]

The above object was achieved by the present invention having the following constitution. (1) A flame-retardant resin composition comprising the following (a), (b), (c) and (d). (A) Polypropylene resin: 20 to 60% by weight (b) Modified polyethylene obtained by modifying polyethylene with an unsaturated carboxylic acid or its derivative: 1 to 20% by weight (c) Metal hydration 35-65% by weight (d) Ethylene copolymer: 0.48> (d) / (a) + (b) + (d) (weight ratio), and (2) Further, (e) the aromatic vinyl-diene block copolymer is added to 0.2 ≧ (e) / (a) + (b) + (d) +.
(E) The flame-retardant resin composition according to item (1), which is contained in the range of (weight ratio). In the flame-retardant resin composition of the present invention, the flame retardancy can be further enhanced by adding (d) an ethylene-based copolymer. By adding (e) the aromatic vinyl-diene block copolymer, the compatibility between the ethylene / propylene random copolymer and the modified polyethylene can be improved, and the mechanical strength and texture of the entire composition can be improved. Furthermore, the following are mentioned as a preferable aspect of the flame-retardant resin composition of this invention. (3) The flame retardant according to the above item (1), wherein the polypropylene resin (a) contains 50% by weight or more of an ethylene / propylene random copolymer having an ethylene component ratio of 0.5 to 6.0% by weight. A resin composition, (4) the flame-retardant resin composition according to (1) above, wherein the modified polyethylene (b) is a polyethylene modified with maleic anhydride, (5) the metal hydrate (c) is water. The flame-retardant resin composition according to item (1), which is magnesium oxide, (6) the ethylene-based copolymer (d) is an ethylene / vinyl acetate copolymer, an ethylene / ethyl acrylate copolymer, or them. The flame-retardant resin composition according to item (1), which is a mixture of (7), (7) the aromatic vinyl-diene block copolymer (e) is styrene-hydrogenated butadiene-styrene copolymer (2). Flame retardant resin Composition. First, each component of the flame retardant resin composition of the present invention will be described in detail.

(A) Polypropylene Resin The polypropylene resin used in the present invention is preferably one containing 50% by weight or more of an ethylene / propylene random copolymer, and a polypropylene resin other than the ethylene / propylene random copolymer. As
Ethylene / propylene block copolymer, propylene homopolymer, propylene / 1-butene random copolymer, propylene / 1-butene block copolymer, propylene / 4-methylpentene-1 random copolymer, propylene / 4-methyl One or two or more resins selected from pentene-1 block copolymer, propylene / 1-hexene random copolymer and propylene / 1-hexene block copolymer may be mixed and used. In particular, it is preferable to use an ethylene / propylene random copolymer having a proportion of 60% by weight or more, preferably 70% by weight or more, and more preferably 80% by weight or more. The ethylene / propylene random copolymer used here is a polymer in which ethylene and propylene are polymerized substantially randomly, and preferably has an ethylene content of 0.5 to 6% by weight, and more preferably 1 to 6. It is 5% by weight. In the random copolymer of the present invention, ethylene is bonded to propylene in a substantially random manner, and unlike the block copolymer, it has almost no domain structure. A random copolymer having an ethylene content of less than 0.5% by weight is not preferable because it has poor filler acceptability and a large decrease in tensile strength and elongation when kneading a metal hydrate or the like. On the other hand, those having an ethylene content of more than 6% by weight are inferior in heat resistance and therefore not preferable. The melt flow rate (MFR) of polypropylene resin is 0.
The range of 1 to 20 g / 10 minutes (load 2.16 kgf, measured at 230 ° C.) is preferable, and 0.1 to 1 is more preferable.
0g / 10min (load 2.16kgf, measured at 230 ℃)
Is the range. The ethylene / propylene random copolymer has a melt flow rate (MFR) of 0.5 to 10 g /
A range of 10 minutes (load 2.16 kgf, measured at 230 ° C.) is preferable.

(B) Modified Polyethylene The modified polyethylene used in the present invention is polyethylene modified with an unsaturated carboxylic acid and / or a derivative thereof (hereinafter referred to as "unsaturated carboxylic acid"). To modify polyethylene with an unsaturated carboxylic acid or the like, for example, in the presence of peroxide, a method of melting and kneading polyethylene and the unsaturated carboxylic acid or the like at a temperature of 1 minute half-life temperature or higher of the peroxide is used. Can be used. Further, the above polyethylene may be reacted with the above unsaturated carboxylic acid or the like in the presence of an inert solvent such as hexane, heptane, benzene or toluene.
The ratio of unsaturated carboxylic acid and peroxide to be kneaded with polyethylene is 100 parts by weight of polyethylene,
It is preferable to set each to 0.01 to 1.0 part by weight and 0.01 to 0.5 part by weight. Examples of polyethylene include ultra low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), and low density polyethylene (LD).
PE), medium density polyethylene (MDPE), and / or high density polyethylene (HDPE) are used. MFR
Is 0.5 to 10 g / min (load 2.16 kgf, 190 ° C)
The range of (measured in) is preferable. Examples of unsaturated carboxylic acids include maleic acid, itaconic acid, and fumaric acid. As the unsaturated carboxylic acid derivative, maleic acid monoester, maleic acid diester, maleic anhydride, itaconic acid monoester, itaconic acid diester,
Examples thereof include itaconic anhydride, fumaric acid monoester, fumaric acid diester, and the like. As the modified polyethylene, polyethylene modified with maleic anhydride is preferable.

(C) Metal Hydrate Examples of the metal hydrate include hydroxyl groups such as aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, aluminum silicate hydrate, aluminum orthosilicate, magnesium silicate hydrate and hydrotalcite. Alternatively, an inorganic compound having water of crystallization may be used. These metal hydrates are 1
Although only one kind may be used or two or more kinds may be used in combination, the most preferable one is magnesium hydroxide. 0.3 to 1.0 in these metal hydrates
Those having a crystal grain size in the range of μ and having almost no aggregation are preferable. Examples of such a material include Kisuma 5 (registered trademark), a magnesium hydroxide flame retardant manufactured by Kyowa Chemical Industry Co., Ltd. Among them, Kisuma 5A, 5B,
Grades having a surface treatment such as 5E and 5J are preferable. (D) Ethylene-based copolymer As the ethylene-based copolymer, an ethylene / vinyl acetate copolymer, an ethylene / acrylic acid ester copolymer, an ethylene / methacrylic acid ester copolymer, an ethylene / acrylic acid copolymer, Examples thereof include ethylene-methacrylic acid copolymers and ethylene-based copolymers such as ethylene-propylene rubber. Among these ethylene-based copolymers, ethylene / vinyl acetate copolymers, ethylene / acrylic acid ester copolymers such as ethylene / ethyl acrylate copolymers, or a mixture thereof are preferable, and ethylene / vinyl acetate copolymers are preferable. Most preferred. Among these ethylene-based copolymers, those having a comonomer ratio of 8 to 30% by weight are particularly preferable. MFR is 0.1-1
0g / 10min (load 2.16kgf, measured at 190 ℃)
Is preferred.

(E) Aromatic vinyl-diene block copolymer An aromatic vinyl-diene block copolymer may be added to the flame-retardant resin composition of the present invention. this is,
Block A consisting essentially of a polymer of an aromatic vinyl compound such as styrene, and block B consisting of a polymer consisting essentially of a polymer of a diene compound such as butadiene. One block A and one block B It is a block copolymer containing the above. As the block A, polystyrene, poly o-methyl styrene, poly m-methyl styrene, poly p-methyl styrene, poly α-methyl styrene, poly β
Blocks of methylstyrene, polydimethylstyrene, polytrimethylstyrene and the like are preferred. Block B includes polybutadiene, polyisoprene, butadiene.
Blocks of isoprene copolymer are preferred. Examples of the block copolymer used in the present invention include polystyrene-polybutadiene-polystyrene block copolymer, polystyrene-polyisoprene-polystyrene block copolymer, poly α-methylstyrene-polybutadiene-poly α-methylstyrene block copolymer. Polymer, poly α-methylstyrene-polyisoprene-poly α-methylstyrene block copolymer, poly β-methylstyrene-polybutadiene-poly β-methylstyrene block copolymer, poly β-methylstyrene-polyisoprene-poly Examples thereof include β-methylstyrene block copolymers and the like, or hydrides of these block copolymers. In the present invention,
A block copolymer in which block A is hardly hydrogenated and block B is selectively hydrogenated is particularly preferable. For example, a styrene-hydrogenated butadiene-styrene copolymer (= styrene / ethylene / butylene / styrene copolymer = SEBS) can be mentioned. You may use the said block copolymer in mixture of 2 or more types.

Next, in the flame retardant resin composition of the present invention, (a) polypropylene resin, (b) modified polyethylene, (c) metal hydrate, (d) ethylene copolymer,
(E) The respective proportions of the aromatic vinyl-diene block copolymer will be described. The proportion of (a) polypropylene resin in the composition is 20-.
60 wt%, the preferred range is 20-55 wt%,
The most preferred range is 25 to 50% by weight. When it is compounded in an amount of 60% by weight or more, the flame retardancy of the composition may decrease. Ethylene in polypropylene resin
The proportion of the propylene random copolymer is preferably 60% by weight or more, and if the proportion is too small, the tensile strength and elongation of the composition may be significantly reduced. The proportion of the modified polyethylene (b) is 1 to 20% by weight, preferably 2 to 15% by weight. When the proportion of modified polyethylene is less than 1% by weight, only a composition having poor tensile strength and low temperature properties can be obtained. On the other hand, a composition having a modified polyethylene content of more than 20% by weight is inferior in fluidity, and thus is difficult to extrude, which is not preferable. The proportion of the metal hydrate (c) is in the range of 35 to 65% by weight, preferably 40 to 60% by weight. If the proportion of the metal hydrate is less than 35% by weight, sufficient flame retardancy cannot be obtained. On the other hand, if it exceeds 65% by weight, a composition excellent in tensile strength, elongation and moldability cannot be obtained. (D) Flame retardancy can be further improved by adding an ethylene-based copolymer to the composition. However, with respect to the total amount of the resin components in the flame-retardant resin composition of the present invention, that is, (a) polypropylene-based resin, (b) modified polyethylene, and (d) ethylene-based copolymer in a total amount of 100 parts by weight, 48
Must be less than wt%. When this ratio is 48% by weight or more, a composition having excellent tensile strength and heat resistance cannot be obtained, which is not preferable. From the viewpoint of improving flame retardancy, it is preferably 10% by weight or more and less than 48% by weight of the total amount of the resin components in the composition.

In addition to the above, in the flame-retardant resin composition of the present invention, an aromatic vinyl-diene block copolymer (e) may be added in order to further improve the mechanical strength, texture and the like. Is all resin components of the composition ((a) +
The proportion in (b) + (d) + (e)) is preferably 20% by weight or less, more preferably 5 to 15% by weight. If the blending amount is more than 20% by weight of the total amount of the resin components, the moldability is remarkably reduced, which is not preferable. Further, in order to further enhance the flame retardancy, carbon black, red phosphorus, tin compounds, fibrous magnesium hydroxide or the like may be added to the resin composition. Further, if necessary, an antioxidant, a copper damage inhibitor, an ultraviolet absorber, a dispersant, a pigment, etc. may be added.
The flame-retardant resin composition of the present invention can be obtained by melt-kneading the above components. To melt-knead each component, a known device such as a twin-screw kneading extruder, a Banbury mixer, and a pressure kneader can be used. Ingredient (a) ~
(D) or (a) to (e) may be kneaded in any order. Further, these components may be dry-blended at room temperature and then melt-kneaded. Furthermore, the composition of the present invention is kneaded with peroxide at the time of melt kneading,
You may crosslink by heating above the decomposition temperature of peroxide. Further, the composition of the present invention may be irradiated with radiation to be crosslinked.

[0011]

EXAMPLES The present invention will be described more specifically below with reference to Examples and Comparative Examples. Examples 1 to 9 and Comparative Examples 1 to 9 Table 1 shows the formulations of the resin compositions of Examples and Comparative Examples.

[0012]

[Table 1]

The compositions of the respective Examples and Comparative Examples were dry-blended at room temperature according to the blending ratio shown in Table 1, and then were blended in a Banbury mixer at a temperature of 180 ° C. for 15 minutes.
It was melt-kneaded for a minute, and then pelletized by a granulator. The composition pellets were tested as follows. The results are shown in Tables 2 and 3.

[Tensile test] The obtained composition pellets were processed by a Brabender lab Laplast mill extruder, 19 mmφL
/ D25 was used to extrude a rod having a diameter of about 2 mmφ, which was used as a tensile test sample. Extruder temperature setting is 200
The extrusion rate was 5 m / min. The tensile test was carried out by cutting 150 mm of a rod-shaped sample, and using a universal tensile tester manufactured by Intesco under the conditions of a tensile speed of 200 mm / min, a chuck distance of 50 mm, and a standard wire distance of 20 mm, and tensile strength and elongation were measured.

[Low Temperature Embrittlement Test] The obtained composition pellets were formed into a sheet having a thickness of 2 mm by hot pressing at 180 ° C.,
It was evaluated according to JIS K 7216. [Heat Deformation Test] Similar to the low temperature embrittlement test, a sheet having a thickness of 2 mm was prepared and evaluated according to JIS K7620. Test temperature 120 ° C, load 1 kg weight. [Flame Retardancy Test] A sheet having a thickness of 3 mm is prepared by hot pressing, and UL-9 described on pages 5 to 7 of UNDERWRITERS LABORATORIES STANDARD standards (January 24, 1980).
Evaluation was performed according to 4HB. The one that the flame disappears between the sample marks is "self-extinguishing", and the one that spreads to the grip is ×
And

[0016]

[Table 2]

[0017]

[Table 3]

As shown in the results of Tables 2 and 3, the compositions shown in the examples are compositions exhibiting excellent mechanical strength, elongation and heat resistance, and having sufficient cold resistance and flame retardancy. Subsequently, in order to evaluate the high-speed molding processability of Examples 1, 4, and 8, a soft copper wire having a diameter of 0.8 mm and a thickness of 0.3 mm was coated at an extrusion temperature of 200 ° C.

[0019]

[Table 4]

As shown in Table 4, although the composition of the present invention is a non-halogen flame retardant composition containing a large amount of magnesium hydroxide, it can be molded at a very high speed of 500 m / min. It turns out that it is an excellent composition.

[0021]

EFFECTS OF THE INVENTION The flame-retardant resin composition of the present invention uses a blend of polypropylene resin and modified polyethylene as a base polymer, and is superior in tensile strength and heat resistance to conventional non-halogen flame-retardant resin compositions. Are better. Further, since it has excellent extrusion processability and is used for manufacturing various extruded products and further has excellent molding processability, the productivity of the processed products can be increased. Further, since it does not contain a halogen-based flame retardant, even if it burns, almost no toxic gas is generated. As described above, when the flame-retardant resin composition of the present invention is used, it is possible to manufacture on a sufficiently commercial basis even with an apparatus that has been using extrusion-molded articles such as tubes and pipes having a good appearance. It can be extruded at high speed onto metal wires and metal pipes.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Dai Hashimoto, 3-4 Tatsumidai Higashi, Ichihara-shi, Chiba (72) Inventor Masaki Nishiguchi 286, Omori-machi, Chuo-ku, Chiba-shi (72) Inventor Shinichi Irie Tokyo 5-39-1yoyogi, Shibuya-ku

Claims (2)

[Claims] 1. A flame-retardant resin composition comprising the following (a), (b), (c) and (d). (A) Polypropylene resin: 20 to 60% by weight (b) Modified polyethylene obtained by modifying polyethylene with an unsaturated carboxylic acid or its derivative: 1 to 20% by weight (c) Metal hydration 35-65 wt% (d) Ethylene-based copolymer 0.48> (d) / (a) + (b) + (d) (weight ratio) 2. Further, 0.2 ≧ (e) / (a) + (b) + of (e) the aromatic vinyl-diene block copolymer is added.
The flame-retardant resin composition according to claim 1, which is contained in a range of (d) + (e) (weight ratio).