JPS61221248A - Flame-retardant resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which does not cause bleedout, by blend ing two specified kinds of magnesium hydroxides, an arom. bromine compd. and an inorg. compd. in the form of a non-acicular crystal to a resin mixture of polypropylene and an ethylene/vinyl acetate copolymer. CONSTITUTION:0.5-20pts.wt. magnesium hydroxide in the form of a needle, 4-80pts.wt. magnesium hydroxide in the form of a non-acicular crystal, 3-150 pts.wt. arom. bromine comp. contg. bromine atoms directly attached to a benzene nucleus (e.g. decabromodiphenyl ether) and 5-150pts.wt. inorg. compd. (e.g. talc or potassium titanate) having an aspect ratio of 2 or above in the form of a non-acicular crystal, are blended with 100pts.wt. polypropylene resin composed of 70-99.9wt% polypropylene and 30-0.1wt% ethylene/vinyl acetate copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polypropylene resin composition having a high degree of flame retardancy.

[Prior Art] Since polypropylene is composed of hydrocarbons, it has the drawback of being easily ignited and combustible. Therefore, various proposals have been made to make polypropylene flame retardant.

In recent years, there has been a tendency for polypropylene used in ¥M, gas products, building materials, etc. to be required to have an increasingly high degree of flame retardancy. For example, the American standards require high flame retardancy of V-1 to V-0 for parts of electrical products such as TV frames. Therefore, exported products to the United States must have a flame retardancy of V-1 to V-0, and naturally a high degree of flame retardancy is required in Japan as well.

In this background, various attempts have been made to use organic flame retardants and inorganic flame retardants as flame retardants. Generally, organic flame retardants have self-extinguishing properties against polypropylene, but have the disadvantage that fire drips occur when burned. On the other hand, inorganic flame retardants, especially magnesium hydroxide, do not cause fire dripping and have some self-extinguishing properties, but
In order to impart a high degree of flame retardant effect such as o, an extremely large amount must be added, for example, to 100 parts by weight of polypropylene; 2
It is preferable to add up to 300 parts by weight to improve the rigidity and dimensional stability of molded products, but up to 300 parts by weight
If a large amount of carcasses are added, pelletizing becomes extremely difficult and impractical. That is, when such a polypropylene composition is made into a molded article, the fluidity in the molding machine and the mold is reduced, and the impact strength of the resulting molded article is also reduced.

[Problems to be Solved by the Invention] In view of the above, the present inventors added 50 to 200 parts by weight of magnesium hydroxide and an aromatic bromine compound in which bromine is directly bonded to the benzene nucleus to 100 parts by weight of the polyolefin. A flame-retardant polyolefin composition containing 5 to 80% by weight of magnesium oxide has already been proposed (
Japanese Patent Publication No. 56-139546). That is, JP-A-58-13
According to No. 9546, by combining the specified inorganic flame retardant and organic flame retardant, it has a high degree of flame retardancy, and the amount of the inorganic flame retardant is 200 parts by weight or less. , it is possible to obtain a polyolefin resin composition that does not cause a decrease in fluidity or a decrease in impact strength of a molded article.

In the meantime, the present inventors developed polyolefin 100 heavy equipment based on the knowledge that blending an inorganic compound with an aspect ratio of 2 or more improves rigidity and at the same time exhibits the effect of preventing fire dripping during combustion. 5 to 5 parts of magnesium hydroxide
We also propose a flame-retardant polyolefin composition containing 150 parts by weight, 21 to 150 parts by weight of an aromatic bromine compound in which bromine is directly bonded to a benzene nucleus, and 5 to 150 parts by weight of an inorganic compound having an aspect ratio of 2 or more. ing. That is, according to the above invention, compared to the invention of JP-A No. 56-139546 mentioned above, the amount of magnesium hydroxide blended can be reduced, and there is no difficulty in pelletizing, which meets the US standard. A high degree of flame retardancy satisfying V-1 to ■-0 could be achieved.

However, in any of the above-mentioned flame-retardant polyolefin compositions, when a propylene homopolymer is used as the polyolefin, aromatic bromination in which bromine atoms are directly bonded to the blended benzene nucleus bleeds out, resulting in molding. It easily penetrates the surface of the product, resulting in poor appearance and loss of commercial value.

[Means to Solve the Problem] As a result of intensive development of the above-mentioned flame-retardant polyolefin composition, the present inventors found that polypropylene 70-99.9% by weight, ethylene-
Polypropylene resin (hereinafter also referred to as polybrown vinyl acetate resin) consisting of 0.1 to 30% by weight of vinyl acetate copolymer.

) was found to significantly reduce the bleed-out of aromatic bromine compounds in which a bromine atom is directly bonded to the benzene nucleus. However, when such a polybrown M-bi-based resin is used, compared to when a propylene homopolymer is used, molded articles of the resulting resin composition suffer from a decrease in rigidity, a decrease in heat distortion temperature, etc. , which is a practical problem. Therefore, as a result of further development, by incorporating needle-like crystalline magnesium hydroxide as the magnesium hydroxide in the polyblown vinyl acetate-based resin composition, low rigidity and heat distortion temperature can be prevented. The present invention has been completed based on the knowledge that it is also effective for improvement.

According to the present invention, 0.5 to 20 parts of acicular crystal magnesium hydroxide is added to 100 parts by weight of polybrown vinyl acetate resin.
Parts by weight, magnesium hydroxide without needle crystals 4 to 8
0 parts by weight, an aromatic bromine compound in which a bromine atom is directly bonded to a benzene nucleus: (~150 parts by weight and an aspect ratio of 2
There is provided a flame-retardant polypropylene resin composition containing 5 to 150 parts by weight of the above-mentioned other non-cylindrical inorganic compound.

That is, according to the polypropylene resin composition based on the polybrown vinyl acetate resin of the present invention, hydroxylated magnesylanoyl, which is not a acicular crystal, which has been conventionally used as an inorganic flame retardant, and hydroxylated acicular crystals. By using magnesium in combination, there is no bleed-out of the aromatic bromine compound in which bromine is directly bonded to the benzene nucleus blended as an organic flame retardant, and molded products with no or improved rigidity and heat distortion temperature. can be obtained. Furthermore, in the flame-retardant polypropylene resin composition of the present invention, improvement in flame retardancy is also observed compared to the case where conventional magnesium hydroxide, which is not a needle crystal, is used as an inorganic flame retardant.

Examples of the polypropylene used in the present invention include propylene homopolymers, random and block copolymers of propylene and α-olefins such as ethylene and butylene, and mixtures thereof. In addition, as an ethylene-vinyl acetate copolymer, vinyl acetate is contained in an amount of 5 to 40% by weight.
An example of this is an ethylene polymer containing a proportion of . In the above-mentioned ethylene-vinyl acetate copolymer, if the content of vinyl acetate is less than the above lower limit, the bleed prevention +h performance of the brominated flame retardant cannot be sufficiently exhibited, and if it is more than the upper limit of -L It becomes more sticky and difficult to disperse uniformly with polypropylene. In addition, the polybrown vinyl acetate resin includes the above-mentioned polypropylene 70 to 99.9% by weight, preferably 30 to 99.5% by weight, and 0.1 to 30% by weight of ethylene-vinyl acetate copolymer, preferably 0.5 to 2% by weight.
However, if the content of the ethylene-vinyl acetate copolymer is less than the above lower limit, sufficient brominated flame retardant bleed prevention performance cannot be exhibited, and if it is more than the above upper limit (1α), thermal deformation may occur. This is not preferable because the temperature decreases significantly.

Next, in order to obtain a polyolefin resin composition having desired flame retardancy in the present invention, magnesium hydroxide as an inorganic flame retardant is added in a total amount to 100 parts by weight of polybrown vinyl acetate resin as a base. It is necessary to blend 5 to 100 parts by weight, and 10 to 1'40 parts by weight. That is, in the polyolefin resin composition described above, if the amount of magnesylano hydroxide is less than 5 parts by weight, the flame retardant effect will not be sufficiently exhibited;
If the amount is more than 0.00 parts by weight, it is not practical because the fluidity and the impact strength of the molded product decrease.

In addition, in the flame-retardant polypropylene resin composition of the present invention, in order to obtain the desired sufficient effect of improving stiffness and heat distortion temperature, the above-mentioned Of the magnesium hydroxide that was
Magnesium hydroxide in the form of 0. f5-20 parts by weight,
It is very important to use preferably a proportion of 1 to 15 parts by weight.

Therefore, in the flame-retardant polypropylene resin composition of the present invention, the amount of magnesium hydroxide that is not acicular crystals is generally 4 parts by weight per 100 parts by weight of the polybrown vinyl acetate resin.
~80 @ ratio of the claw portion.

If the amount of magnesium hydroxide in the acicular crystals is more than the above 20 parts by weight, it is not only uneconomical, but also is preferable because flow marks are likely to occur in the resulting flame-retardant polypropylene resin molded product. do not have.

The acicular crystalline magnesium hydroxide used in the present invention generally has crystal grains with an aspect ratio of 5 or more and a short diameter of]
It is preferable that the content is 25% or more of Olt or less. In addition, any magnesium hydroxide without needle crystals can be used, but the particle size is 0.1 to 5.
0 It s preferably 0.1 to 2oμ, also H)'
: When using a material with a 1' specific surface area of 20rn"7g or less, it is preferable to obtain a molded product with improved impact resistance, good surface condition, and no silver streaks. Furthermore, magnesium hydroxide is added in advance. Those surface-treated with a surfactant such as sodium stearate and sodium lauryl sulfonate are preferably used because they have the advantage of improved dispersibility and fluidity.

Furthermore, in the present invention, it is also important to use an aromatic bromine compound in combination with magnesium hydroxide. Aromatic bromine compounds include compounds in which bromine is directly bonded to a benzene nucleus, such as brominated benzenes such as hexabromobenzene and pentabromobenzene; brominated toluenes such as pentabromotoluene and tetrabromotoluene; tetrabromoxylene; Brominated xylenes such as tribromoxylene; Brominated phenols and metal salts thereof such as pentabromophenol, tetrabromoresorcin, tribromopyrogallol, and sodium pentabromoferulate; Brominated anilines such as pentabromoaniline and tetrabromoaniline; pentabrome Benzoic acid, tetrabromobenzoic acid and its derivatives; heterosubstituted brominated benzenes such as tetrabromosalicylic acid, tetrabromotoluic acid, and tetrabromucresol; brominated phthalic anhydrides such as tetrabrominated phthalic anhydride; brominated biphenyls; bromine Brominated diphenyl derivatives such as brominated diphenyl ether and brominated diphenylthioether; brominated naphthalene derivatives; brominated anthracene derivatives; brominated aromatic polymers such as tribromopolystyrene; Among these, those having a bromine content of 55% or more are particularly preferably used.

Even if bromine is directly bonded to the benzene nucleus, compounds with bromine bonded to the side chain, such as tetrabromide bisphenol A bis (tribromide propyl ether), tetrabromide dihydroxy diphenyl sulfone, etc. (propyl tribromide ether) etc. cause fire dripping and are unsuitable for use in the present invention. Furthermore, aliphatic bromine compounds that are frequently used as flame retardants for polyolefins, such as tetrabromobutane and tribro-1-propane, also cause flaming and cannot be used in the present invention.

The blending amount of the aromatic bromine compound in the present invention is 3 to 150 parts by weight, preferably 5 to 100 parts by weight, based on 10 () heavy electric parts of the polybrown vinyl acetate resin. If the amount of the aromatic bromine compound blended is less than the above lower limit, the self-extinguishing property will be insufficient.

On the other hand, if it exceeds the above upper limit, it is not only economically undesirable but also difficult to knead and pelletize using an extruder.

In the present invention, an inorganic compound having an aspect ratio of 2 or more is used together with two types of magnesium hydroxide and an aromatic bromine compound, so that even if the amount of magnesium hydroxide is reduced, the rigidity will be impaired. This is important in order to obtain a polypropylene resin composition that has the desired flame retardancy without any flame retardance. ) (1) According to the present invention, compared to magnesium hydroxide alone as an inorganic compound, by using magnesium hydroxide together with an inorganic compound having an aspect ratio of 2 or more,
The same flame retardant effect can be obtained by reducing the amount of magnesium hydroxide.

The inorganic compound having an aspect ratio of 2 or more is a non-cone-like compound having no needle-like crystals, and includes talc, mica, volasnite, potassium titanate, etc., and talc is particularly preferably used.

The amount of the inorganic compound having an aspect ratio of 2 or more in the present invention is 5 to 150 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the polybrown vinyl acetate resin. If the amount of the inorganic compound having an aspect ratio of 2 or more is less than the above lower limit, the resulting polypropylene resin composition will not have a sufficient improvement in rigidity and fire prevention effect.

On the other hand, if the amount exceeds the above upper limit, it becomes difficult to knead and pelletize the obtained polypropylene resin composition using an extruder, which is not preferable.

The present invention is a polyolefin resin made by blending a polybrown vinyl acetate resin with magnesium hydroxide in the form of needle crystals, magnesium hydroxide without needle crystals, an aromatic bromine compound, an inorganic compound with an aspect ratio of 2 or more, and further antimony dioxide. A composition is provided. That is, by blending antimony trioxide, a higher degree of flame retardation can be achieved. The amount of antimony trioxide is generally 10 to 100% by weight based on the aromatic bromine compound.

In the present invention, polypropylene, ethylene-vinyl acetate copolymer, magnesium hydroxide with needle-like crystals, magnesium hydroxide without needle-like crystals, aromatic bromine compounds in which bromine is directly bonded to the benzene nucleus, and inorganic compounds with an aspect ratio of 2 or more are used. The order of mixing the compounds, and even antimony dioxide, is not particularly limited, and each component may be mixed at the same time, or several types may be mixed in advance, and the remaining components may be mixed later. Also, the mixing method is not particularly limited, and generally a tumbler set blender, ■
This is done using a mold blender, Henschel mixer, ribbon mixer, etc. Furthermore, it is also possible to adopt a method of changing the mixing order and equipment, such as mixing several types in advance in a Henschel mixer, then adding the rest and mixing in a tumbler.

The polypropylene resin composition of the present invention basically consists of polypropylene, ethylene-vinyl acetate copolymer, magnesium hydroxide with needle-like crystals, magnesium hydroxide without needle-like crystals, an aromatic bromine compound, and an inorganic compound with an aspect ratio of 2 or more. The composition is composed of a compound and further antimony dioxide, but in addition to these components, conventionally known stabilizers, colorants, antistatic agents, lubricants, nucleating agents, etc. may be added as necessary.

[Function and Effect] By using a mixture of polypropylene and ethylene-vinyl acetate copolymer as the base resin in the present invention,
Bleed-out of aromatic bromine compounds can be prevented. Although it is not clear why this bleed-out of aromatic bromine compounds can be prevented, it is presumed that the difference in crystalline state compared to polypropylene or the adsorption effect of brominated flame retardants by acetyl groups may be the cause. . Moreover, the polypropylene resin composition of the present invention has UT, 94
It has a high degree of flame retardancy of V-1 to V-0 according to the standards. The reason for such flame retardancy is not clear, but it is believed that aromatic bromine compounds, in which bromine is directly bonded to the benzene nucleus, act synergistically with needle-shaped magnesium hydroxide and non-sword-shaped magnesium hydroxide. It is estimated that the material exhibits high flame retardancy.

Furthermore, when magnesium hydroxide is used, flame retardancy is improved by using magnesilla hydroxide, which has needle-like crystals, than when using only magnesium hydroxide, which does not have sword-like crystals, but the reason for this is not clear. do not have. However, I would like to make an assumption as follows. In other words, it is presumed that the acicular crystalline magnesium hydroxide conducts heat quickly during combustion due to its shape characteristics, and that the decomposition of magnesium hydroxide and the development of the flame retardant action are accelerated. Therefore, sufficient combustion effects can be achieved even with a small addition of magnesium hydroxide.

Furthermore, the reason for the improvement in rigidity and heat distortion temperature is thought to be due to the aspect ratio of magnesium hydroxide in the acicular crystals, and the improvement in heat distortion temperature is particularly remarkable compared to other inorganic compounds.

[Examples] In order to explain the present invention more specifically, Examples and Comparative Examples will be described below, but the present invention is not limited to these Examples. The experimental results of the combustion tests shown in the Examples and Comparative Examples were conducted in accordance with the vertical method of the U.I.94 standard, and the average self-extinguishing time was 2 times each for 10 combustibility test pieces. i.e. total 2
The average self-extinguishing time after 0 flame ignitions is shown. Furthermore, the maximum self-extinguishing time was the maximum value of the self-extinguishing times after the 20 ignitions. The extent to which the cotton under the test piece ignited due to "flame" from the test piece was expressed by how many out of 10 cotton strands were ignited. For example, if 3 out of 10 lights were ignited, 3710 would be displayed.

The shape of the test piece was 5 inches x 0.5 inches x 1/8 inch.

In addition, the bending elastic modulus and heat distortion temperature were measured using AS
TMD790 and AS'rMr) 64.8 (load 4.
6 kg/cm).

In addition, bleed-out was measured using injection molding at a resin temperature of 200°C and a mold temperature of 40°C.
．． A 3 cm flat plate was prepared, and the test piece was left in an oven at 150"C for 100 hours, and then the surface was observed.

Example 1 Polypropylene [homopolymer II MI9 (
PP)] and ethylene vinyl acetate copolymer [vinyl acetate content 28 wt%, MT6 (denoted as EVA-1)
] Magnesium hydroxide with needle-like crystals (product name, Kisumafu B), magnesium hydroxide without needle crystals (product name, Kisuma 5A), decabrom diphenyl ether, talc (aspect ratio 6), antimony dioxide, and other fillings Kakuda Manufacturing Co., Ltd. using a super mixer with the materials and heat stabilizers in the proportions shown in Table 1. Mixed with water. The heat stabilizers include 2,6-tert-butyl-4-methylphenol, dilaurylthiopropione, and calcium stearate at 0.1% and 0.2% in the total composition, respectively.
% and 0.1%, and then molded using an extruder with a kneader (manufactured by Nakatani Kikai ■) to obtain a test piece.

Using this test piece, a combustion test (U 1., Standard 5b94
Vertical method) was performed to measure the average and maximum self-extinguishing times and the cotton ignition rate, and these values are also listed in Table 1. Also,
The heat distortion temperature was also measured, and this value is also listed in Table 1.

Furthermore, the presence or absence of bleed-out was observed, and the results were also the first.
Also listed in the table.

Example 2 Polypropylene [homopolymer; M[9
(denoted as PP)] and] Ethylene-vinyl acetate copolymer vinyl acetate content 15 wt%, MlB (denoted as EVA-2)], needle crystal and non-acicular crystal magnesium hydroxide (all manufactured by Kyowa Kagaku Kisumahu B", r Kisuma5A
(trade name), decabromidiphenyl ether, antimony trioxide, and talc were mixed in the same manner as in Example 1 in the proportions shown in Table 2. Hereinafter, the test was conducted in the same manner as in Example 1.

The results are also listed in Table 2.

Example 3 Ethylene-vinyl acetate copolymer (vinyl acetate content 15w) was added to 97 heavy acid parts of polypropylene (homopolymer: MI9).
t%, M) 6) 3 parts by weight, 5 parts by weight of magnesium hydroxide with needle-like crystals, 4 parts by weight of magnesium hydroxide without needle-like crystals
Example 1 was carried out in the same manner as in Example 1, except that 5 parts by weight of talc, 50 parts by weight of talc, antimony trioxide, and 25 parts by weight of the bromine compound shown in Table 2 were used.

The results are also listed in Table 3.

Example 4 97 parts by weight of polypropylene (homopolymer: MI9) and ethylene-vinyl acetate copolymer (vinyl acetate content: 15 wt%)
, M+6) 3 parts by weight of magnesila hydroxide J1 without needle crystals in the ratio (parts by weight) shown in Table 4, and non-acicular crystals having a predetermined aspect ratio (shown in Table 4). The same procedure as in Example 1 was conducted except that an inorganic compound was used.

The results are also listed in Table 4.

Claims (6)

[Claims] (1) 0.5 to 20 parts by weight of acicular crystal magnesium hydroxide to 100 parts by weight of a polypropylene resin consisting of 70 to 99.9% by weight of polypropylene and 0.1 to 30% by weight of ethylene-vinyl acetate copolymer. parts by weight, 4 to 80 parts by weight of magnesium hydroxide without needle crystals, 3 to 150 parts by weight of an aromatic bromine compound in which a bromine atom is directly bonded to a benzene nucleus, and other non-acicular crystals with an aspect ratio of 2 or more. A flame-retardant polypropylene resin composition comprising 5 to 150 parts by weight of an inorganic compound. (2) The resin composition according to claim 1, wherein the ethylene-vinyl acetate copolymer has a vinyl acetate content of 10 to 30% by weight. (3) The resin composition according to claim 1, wherein the acicular crystal magnesium hydroxide has an aspect ratio of 5 or more and a particle width of 10 μ or less. (4) The resin composition according to claim 1, wherein the aromatic bromine compound is decabromidiphenyl ether. (5) The resin composition according to claim 1, wherein the other non-acicular inorganic compound having an aspect ratio of 2 or more is talc. (6) 0.5 to 20 parts by weight of magnesium in the form of acicular crystals to 100 parts by weight of a polypropylene resin consisting of 70 to 99.9% by weight of polypropylene and 0.1 to 30% by weight of ethylene-vinyl acetate copolymer , 4 to 80 parts by weight of magnesium hydroxide without needle crystals, 3 to 150 parts by weight of an aromatic bromine compound in which a bromine atom is directly bonded to a benzene nucleus,
A flame-retardant resin composition containing 5 to 150 parts by weight of another non-acicular crystalline inorganic compound having an aspect ratio of 2 or more and 10 to 100 parts by weight of antimony trioxide based on the aromatic bromine compound. .