JP2001031803A - Flame-retardant resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame retardant resin composition excellent in abrasion resistance and processability and shell-forming properties during burning in spite of being added with a flame retardant inorganic compound. SOLUTION: This flame retardant resin composition is constituted by blending 100 pts.wt. of a composition consisting of 95-5 wt.% of (A) an ethylene-vinyl acetate copolymer, 5-95 wt.% of (B) an ethylene-(meth)acrylic acid ester copolymer with 25-250 pts.wt. of (C) a flame retardant inorganic compound, 0-30 pts.wt. of (D) an ethylene-unsaturated carboxylic acid random copolymer or (E) a modified product of a partially saponified ethylene-vinyl acetate copolymer and 0-75 pts.wt. of (F) a thermoplastic polymer. A part of the aforesaid component (A) and/or the component (B) may be replaced by its or their acid-modified products. As (D) the ethylene-unsaturated carboxylic acid random copolymer, a random copolymer of ethylene with acrylic acid or methacrylic acid and as (F) the thermoplastic polymer, a straight chain ethylene-α-olefin copolymer polymerized by using a metallocene catalyst are preferably used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an olefin-based flame-retardant resin composition, and more particularly, to a composition having excellent scratch resistance and processability despite the presence of an inorganic compound. The present invention relates to a flame-retardant resin composition having excellent shell-forming properties during combustion.

[0002]

2. Description of the Related Art Olefin polymers are generally excellent in electrical properties, mechanical properties and processability.
Widely used as an electrical insulating material. In particular, for applications such as electric wires and cables, materials that are well-balanced in strength, low-temperature properties, scratch resistance, hardness, etc. are required.Because of these properties, ethylene / unsaturated ester random copolymers are used. Widely used.

[0003] However, such an ethylene-based copolymer is flammable, so that when it is used for an electrical insulating material, it is necessary to perform a flame-retardant treatment. As a method of flame retardation of an ethylene copolymer, it is known that an inorganic compound is blended.However, in order to achieve a sufficient flame retarding effect, it is necessary to blend a large amount of the inorganic compound. However, in this case, there is a problem that the original processability and mechanical properties of the ethylene copolymer are impaired.

[0004] In order to avoid such a problem, there has been proposed a surface modifier for an inorganic compound to be added to an ethylene copolymer, and an attempt has been made to add a modified resin grafted with an unsaturated carboxylic acid such as maleic acid. However, even if the surface of the inorganic compound is modified, the mechanical strength is improved, but the scratch resistance is not improved, and when the acid-modified resin is blended, the mechanical strength and the resistance are improved. Although the effect of improving the abrasion is seen, in this case, there is a problem that the workability is significantly reduced.

[0005] In addition, a method of blending antimony oxide and a halide is also known. However, this method involves a danger of generating toxic gas once a fire occurs, and is a preferable method. Absent.

As disclosed in Japanese Patent Publication No. 7-103273, 70 to 20% by weight of an olefin polymer resin and / or elastomer, aluminum and / or
Or a mixture of magnesium hydroxide or a mixture thereof containing 30% by weight or less of magnesium carbonate.
0% by weight and 100 parts by weight of a copolymer of ethylene and at least one monomer selected from unsaturated carboxylic acids, derivatives thereof and vinyl esters (excluding epoxy groups) 0.02 To 25 parts by weight, and an ethylenically unsaturated epoxy compound content of 0.5 to 50% by weight
A self-extinguishing polymer composition comprising 0.001 to 3 parts by weight of a copolymer of ethylene and an ethylenically unsaturated epoxy compound is known. It is intended to improve cold resistance without impairing trauma resistance, and has excellent scratch resistance and workability,
There is no suggestion for the present invention which aims at a flame-retardant resin composition having excellent shell formation during combustion.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a flame-retardant resin composition which is excellent in abrasion resistance, workability, and shell formation during combustion despite the fact that an inorganic compound is blended. To provide things. In the present invention, the shell-forming property during combustion is
When the situation during combustion is visually observed, what forms a shell or a shell that is strong itself, and those that drip while melting without forming a shell, have excellent shell formability. Do not say.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to achieve the above-mentioned object, and comprises (A) ethylene-vinyl acetate copolymer as a basic polymer of a flame-retardant resin composition. An important technical feature is that a composition comprising 95 to 5% by weight of a polymer and 5 to 95% by weight of an ethylene / (meth) acrylate copolymer (B) is used.

That is, according to the present invention, (A) 95 to 5% by weight of an ethylene / vinyl acetate copolymer and (B) an ethylene / (meth) acrylate copolymer 5 to 9% by weight.
(C) 25 to 250 parts by weight of a flame-retardant inorganic compound, (D) an ethylene / unsaturated carboxylic acid random copolymer or (E) an ethylene / vinyl acetate copolymer, based on 100 parts by weight of a 5% by weight composition. 0 to 30 parts by weight of acid-modified partially saponified polymer and (F) thermoplastic polymer 0 to 75
There is provided a flame-retardant resin composition characterized by blending in parts by weight.

Further, according to the present invention, (A) a part of the ethylene / vinyl acetate copolymer and / or (B) a part of the ethylene / (meth) acrylate copolymer is obtained by acid-modifying the copolymer. The flame-retardant resin composition is provided as a body.

According to the present invention, the flame-retardant inorganic compound (C) is silica, alumina, calcium carbonate, talc, clay, zeolite, carbon black, glass fiber, basic magnesium carbonate, magnesium hydroxide and The flame-retardant resin composition is provided, which is at least one selected from the group consisting of aluminum hydroxide, or a surface thereof treated with a fatty acid amide, a fatty acid salt, a fatty acid ester or a silane coupling agent.

Further, according to the present invention, there is provided the above flame-retardant resin composition, wherein the (D) random copolymer of ethylene and unsaturated carboxylic acid is a random copolymer of ethylene and acrylic acid or methacrylic acid. Is done.

Further, according to the present invention, there is provided the above flame-retardant resin composition wherein the thermoplastic polymer (F) is a linear ethylene-α-olefin copolymer polymerized using a metallocene catalyst. Is done.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a flame-retardant resin composition comprising, as polymers, (A) 95 to 5% by weight of an ethylene / vinyl acetate copolymer and (B) ethylene / (meth) acrylic. It is essential to use a composition consisting of 5 to 95% by weight of an acid ester copolymer, and a part of the above (A) and / or (B) is replaced by an acid modified product of the copolymer. Is also good. By adopting the composition of these copolymers, ethylene copolymers such as those obtained by blending a flame-retardant inorganic compound with a conventional ethylene / (meth) acrylate copolymer alone can be used. A composition having excellent flame retardancy can be obtained without impairing the processability and mechanical properties of the composition.

(A) The ethylene / vinyl acetate copolymer has an ethylene component of 40 to 97% by weight, preferably 50 to 95% by weight, and a vinyl acetate component of 3 to 60% by weight.
% By weight, preferably 5 to 50% by weight of the copolymer is used. 190 of ethylene-vinyl acetate copolymer
° C, melt flow rate (MF
R) is 0.1 to 50 g / 10 min, preferably 0.1 g / min.
2 to 30 g / 10 min.

(B) The ethylene / (meth) acrylate copolymer contains 50 to 97% by weight, preferably 60 to 95% by weight of an ethylene component, and 3 to 80% by weight of a (meth) acrylate component. Preferably, 5 to 75% by weight of the copolymer is used. 190 ° C of ethylene / (meth) acrylate copolymer,
Melt flow rate (MFR) at 2160g load
Is 0.1 to 50 g / 10 min, preferably 0.2 to 30 g / 10 min.

As the (meth) acrylic acid ester, it is preferable to use an alkyl ester of an unsaturated carboxylic acid such as acrylic acid or methacrylic acid having 1 to 12 carbon atoms, especially about 1 to 8 carbon atoms. More specifically,
Examples thereof include methyl acrylate, ethyl acrylate, isopropylyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-2 ethylhexyl acrylate, methyl methacrylate, and ethyl methacrylate.

(A) The ethylene / vinyl acetate copolymer and
(B) Ethylene / (meth) acrylate copolymer is
A part thereof may be replaced with an acid-modified copolymer.
Examples of the acid-modified product include a graft-modified product of the copolymer with an unsaturated carboxylic acid or a derivative thereof. The amount of grafting of the acid-modified product was 0.1% with respect to the copolymer.
About 10% by weight is preferred.

The unsaturated carboxylic acids include, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and the like, and derivatives thereof include acid anhydrides, esters, amides, metal salts, and the like. Examples include maleic anhydride, citraconic anhydride, itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, and the like. . Among these acid-modified products,
A modified maleic anhydride is preferably used.

The above (A) ethylene / vinyl acetate copolymer and
(B) The ethylene / (meth) acrylate copolymer is (A) / (B) = 5 to 95/5 to 95% by weight, preferably 10 to 75/25 to 90% by weight.
When the mixing ratio of (A) is less than the above range, scratch resistance is poor, and when it exceeds the above range, excellent flame retardancy cannot be obtained, which is not preferable.

The flame-retardant inorganic compound (C) in the present invention is a compound known per se which is blended for the purpose of making the polymer flame-retardant. Examples thereof include silica, alumina, calcium carbonate, and the like.
Examples include fillers such as talc, clay, zeolite, carbon black, and glass fibers, and hydroxides of metals such as basic magnesium carbonate, magnesium hydroxide, and aluminum hydroxide. Alternatively, those obtained by treating the surfaces of these inorganic compounds with a fatty acid amide, a fatty acid salt, a fatty acid ester, a silane coupling agent, or the like may be used. The particle size of the flame-retardant inorganic compound is not particularly limited. However, considering the miscibility with the polymer composition and the appearance of the molded product, the particle size is 0.05 to 20 μm, particularly 0.1 to 5 μm. Of these are preferably used.

The (D) ethylene / unsaturated carboxylic acid random copolymer, which is an optional component in the present invention, is composed of 75 to 99% by weight, preferably 80 to 96% by weight of ethylene and unsaturated carboxylic acid or a derivative thereof. Or 2
5% by weight, preferably 4 to 20% by weight of a random copolymer, and unsaturated carboxylic acids or derivatives thereof include acrylic acid, methacrylic acid, fumaric acid, maleic acid, maleic anhydride, monomethyl maleate, and maleic acid. Monoethyl acid is mentioned, and among them, acrylic acid or methacrylic acid is preferable. This compounding component further improves the scratch resistance and flame retardancy of the flame retardant resin composition.

The ethylene / unsaturated carboxylic acid copolymer used in the present invention may be copolymerized with another monomer in addition to ethylene and the unsaturated carboxylic acid. Such other monomers include vinyl acetate, vinyl esters such as vinyl propionate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate,
N-butyl acrylate, 2-ethylhexyl acrylate,
Examples thereof include unsaturated carboxylate esters such as methyl methacrylate, dimethyl maleate, and diethyl maleate, carbon monoxide, sulfur dioxide, and the like. Among them, acrylate esters and methacrylate esters are particularly preferable.

Unsaturated carboxylic acids include alkali metals such as sodium, potassium and lithium, magnesium,
A material neutralized with an alkaline earth metal such as calcium, a divalent metal such as zinc, copper, cobalt, and nickel, or a trivalent metal such as aluminum may be used. The degree of neutralization can be 0 to 100 mol% based on the carboxylic acid.

Of the ethylene / unsaturated carboxylic acid copolymer,
Melt flow rate at 190 ° C. and 2160 g (M
FR) is 0.5 to 750 g / 10 min, preferably 1 to 500 g / 10 min. If the melt flow rate is less than 0.5 g / 10 minutes, the MFR of the flame-retardant resin composition is extremely low, and molding is difficult.
If it exceeds 750 g / 10 min, it cannot be used because the flame-retardant inorganic compound cannot be uniformly dispersed.

The acid-modified partially saponified ethylene-vinyl acetate copolymer (E), which is another optional component, is the same as the ethylene-vinyl acetate copolymer used as the component (A). A partially saponified ethylene-vinyl acetate copolymer modified with an acid such as acrylic acid, maleic acid, or maleic anhydride is used. As an example, "Dumilan C1591" (trade name, manufactured by Takeda Pharmaceutical Co., Ltd.) may be mentioned.

These optional components (D) and (E) are used in an amount of up to 30 parts by weight, preferably 0 to 20 parts by weight, based on 100 parts by weight of the polymer composition. Flame retardancy and abrasion resistance are further improved by blending these components (D) and (E).

The thermoplastic polymer (F), which is another optional component, includes high-, medium-, and low-density polyethylene, ethylene-α-olefin copolymer, polypropylene, poly-1-butene, and poly-4-. Methyl-1-pentene and the like. Polyethylene may be produced by a high-pressure method, a medium-pressure method, or a low-pressure method, or may be produced by using any catalyst system, but in particular, linear polyethylene polymerized using a metallocene catalyst. Ethylene-α-olefin copolymer (metallocene LLDPE) is preferably used. The thermoplastic polymer is blended in an amount of up to 75 parts by weight, preferably 0 to 49 parts by weight, based on 100 parts by weight of the polymer composition. By incorporating this component (F), the heat resistance of the flame-retardant resin composition is further improved.

Various additives known per se can be added to the flame-retardant resin composition of the present invention as long as the purpose is not impaired. Examples of such additives include primary antioxidants such as hindered phenols, antioxidants such as phosphorus-based or sulfur-based secondary antioxidants, light stabilizers such as HALS (hindered amine), benzotriazole-based ,
UV absorbers such as benzophenone-based UV absorbers, pigments such as inorganic pigments and phthalocyanines and azo pigments, dyes such as oil-soluble dyes, lubricants such as metal soaps, stearic acid, silicone, and blocking inhibitors such as silica and oleamide. , Blowing agents such as azodicarbonamide, DC
P and other crosslinking agents, and phosphorus-based flame retardants.

The flame-retardant resin composition of the present invention is obtained by melt-kneading the above components with a kneading machine known per se such as a Banbury mixer, a pressure kneader, a single-screw extruder, a twin-screw extruder or a roll.
Through a process such as pelletization, if necessary, it is formed into a flame-retardant resin molded product by a molding means suitable for a target object such as extrusion molding, injection molding, compression molding, hollow molding, or foam molding. Crosslinking by electron beam irradiation is also possible.

[0031]

According to the present invention, in spite of the fact that an inorganic compound is blended, it has excellent scratch resistance and processability, retains the mechanical strength inherent to the base polymer, and burns. The present invention provides an olefin-based flame-retardant resin composition having excellent shell-forming properties at the time. The olefin-based flame-retardant resin composition provided by the present invention has excellent electrical properties and can be preferably used for applications such as electric wire parts. Further, the flame-retardant resin composition can be made into various molded articles requiring flame retardancy by the above-described various molding methods.

Examples of such molded articles include, for example,
Civil engineering fields such as artificial turf, mats, waterproof sheets, tunnel sheets, roofing, etc., pipe applications such as hoses and tubes, home appliances such as packing and vibration control sheets, carpet backing materials, door panel waterproof sheets, mudguards, malls Automotive applications, such as furniture, floor materials, foam sheets and other building materials,
Examples thereof include those used in fields such as communication cables, power cables, wiring in equipment, plugs, contraction tubes, and other cable applications.

[0033]

EXAMPLES The present invention will be described below with reference to examples, but these examples are intended to disclose preferred embodiments of the present invention and are not intended to limit the present invention. The raw material resins, inorganic compounds, types of additives used in Examples and Comparative Examples, and methods for testing physical properties of the obtained polymer compositions are as follows.

1. Raw materials (1) Ethylene-vinyl acetate copolymer (2) Inorganic compound magnesium hydroxide (average particle size 0.8 μm) (3) Ethylene-acrylate copolymer (4) Acid copolymer / acid modified product (5) Thermoplastic polymer Metallocene LLDPE (MFR: 1.5 g / 10 min Density: 916 kg / m ³ ) (6) Other additives Antioxidant [trade name “Irganox 1010” (manufactured by Ciba Specialty Chemicals)

2. Method for Testing Physical Properties of Polymer Composition (1) Oxygen Index: According to JIS K7201 An oxygen index was measured as an index of flame retardancy. (2) Shell formation: The combustion state of the sample at the time of measuring the oxygen index was visually observed, and evaluated according to the following criteria. 〇: Shell is formed or shell is strong △: Drip is not seen, but shell formation is weak ×: Flows down while melting (Drips) (3) Taper abrasion: conforms to JIS K7204 As an index of abrasion, taper abrasion was measured. (4) Heat resistance: The sheet sample was left in an oven maintained at a constant temperature, and the appearance change after 48 hours was visually observed, and evaluated according to the following criteria. ：: No change in appearance (oven temperature 100 ° C) 〇: No change in appearance (oven temperature 90 ° C) ×: Change in appearance (oven temperature 90 ° C) (5) Melt flow rate (MFR): JIS K676
Based on 0 Resin temperature: 190 ° C., load: 2160 g (6) Appearance The state of the strand at the time of MFR measurement was visually observed and evaluated according to the following criteria. 〇: Smooth strand skin △: Slightly rough strand ×: Strand rough skin

<Examples 1 and 2> The raw materials were mixed at the mixing ratios shown in Table 1, heated and kneaded with a small pressure kneader, and then charged into a 6-inch roll and kneaded with a roll to obtain a polymer composition. Prepared. In addition to examining the processability (MFR and strand appearance at the time of measurement) of this composition, a sheet having a thickness of 1 mm or 3 mm was prepared by press molding, and the oxygen index and shell formation were measured. did. Further, the taper abrasion was measured and evaluated for abrasion resistance. The results are shown in Table 1. As is evident from the results in Table 1, the polymer composition of the present invention obtained in the Examples was the same as the conventional flame-retardant resin composition, although the amount of the flame retardant was the same. A high oxygen index was obtained, and the composition was a hard shell. In addition, it had excellent scratch resistance and moldability.

<Embodiments 3 to 5> In Embodiment 1,
Further, a copolymer having an acid group was blended, and preparation and evaluation of a sample were performed in the same manner as in Example 1. The results are shown in Table 1. From the results in Table 1, it can be seen that the composition containing the copolymer having an acid group has further improved flame retardancy.

<Example 6> EVA-2 and EVA-3 were used in place of EVA-1 of Example 1, and a thermoplastic polymer was further blended. Preparation and evaluation were performed. The results are shown in Table 1. From the results in Table 1, the composition further blended with the thermoplastic polymer is not only excellent in flame retardancy and scratch resistance, but also excellent in heat resistance, and both EVA and EEA It is also effective to use two or more copolymers having different contents of VA, EA or EA.

<Examples 7 to 15> A flame-retardant resin composition was prepared in the same manner as in Example 1 except that the types and combinations of the copolymers (A) and (B) were changed as shown in Table 2. Prepared and measured physical properties. The results are shown in Table 2. From the results in Table 2, it can be seen that Examples 7 to 9 show that the shell formation is good and the flame retardancy is excellent even when the EVA is rich;
The shell can be formed even at a low content, and the flame retardancy is very good; Example 11 shows that the shell can be formed even at a high MFR and the flame retardancy is very good. Examples 12 and 13 show that a shell can be formed and flame retardancy is high even with a small amount of a flame retardant; Example 15 uses an acid-modified product of EVA or a part of EEA. It can be seen that this is also effective in shell formation, flame retardancy, and moldability.

<Comparative Examples 1 to 4> Each raw material was blended at the blending ratios shown in Tables 1 and 2, and a conventional flame-retardant resin composition was prepared in the same manner as in Example 1, and the physical properties were measured. The results are shown in Tables 1 and 2. From the results shown in Table 1, it can be seen that those of Comparative Examples 1 and 2 have lower oxygen indices and insufficient abrasion resistance than Examples 1 to 6. In the case of Comparative Example 1, no shell was formed, and a severe drip phenomenon was caused. Also, from the results in Table 2, it is found that Comparative Example 3 has a MFR higher than the MFR specified in the present invention.
It can be seen that shell formation is weak in FR EVA, and there is a problem in heat resistance. Furthermore, it can be seen that Comparative Example 4 cannot form a shell even when EVA or an acid-modified product in which EEA is not a base resin is blended.

[0041]

[Table 1]

[0042]

[Table 2]

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Claims (5)

[Claims] (A) Ethylene / vinyl acetate copolymer 95
1 to 5% by weight and (B) 5 to 95% by weight of an ethylene / (meth) acrylate copolymer
(C) 25 to 250 parts by weight of the flame-retardant inorganic compound, (D) ethylene / unsaturated carboxylic acid random copolymer or (E) ethylene / vinyl acetate copolymer 0 to 30 parts by weight of acid-modified form and (F)
A flame-retardant resin composition comprising 0 to 75 parts by weight of a thermoplastic polymer. 2. A part of (A) an ethylene / vinyl acetate copolymer and / or (B) an ethylene / (meth) acrylate copolymer is an acid-modified copolymer of the copolymer. The flame-retardant resin composition according to the above. 3. The flame-retardant inorganic compound (C) is silica, alumina, calcium carbonate, talc, clay, zeolite,
At least one selected from the group consisting of carbon black, glass fiber, basic magnesium carbonate, magnesium hydroxide, and aluminum hydroxide, or those obtained by treating the surface thereof with a fatty acid amide, a fatty acid salt, a fatty acid ester, or a silane coupling agent. 3. The flame-retardant resin composition according to claim 1, which is a seed. 4. The flame-retardant resin according to claim 1, wherein the (D) random copolymer of ethylene and unsaturated carboxylic acid is a random copolymer of ethylene and acrylic acid or methacrylic acid. Composition. 5. The flame-retardant resin according to claim 1, wherein (F) the thermoplastic polymer is a linear ethylene-α-olefin copolymer polymerized using a metallocene catalyst. Composition.