JPH0517932B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a flame-retardant polyolefin composition having high thermal stability and blooming resistance. [Prior Art and Problems] Since polyolefin is composed of carbon and hydrogen, it has the drawback of being easily ignited and combustible. Therefore, various proposals have been made to make polyolefin flame retardant. In recent years, polyolefins used in electrical products, building materials, etc. are required to have increasingly high flame retardancy. For example, in the UL standards of the United States, components of electrical products such as TV frames and audio components are required to have a flame retardancy of V-1 to V-0 or V-2, respectively. Furthermore, in our country as well, various types of flame retardancy are naturally required. In this background, various attempts have been made to use inorganic flame retardants and organic flame retardants as flame retardants for polyolefins. In general, inorganic flame retardants have good fire-retardant properties, but in order to provide sufficient flame retardant effects, they require a large amount of filling. On the other hand, organic heat retardants have a greater flame retardant effect than inorganic flame retardants, so they only need to be added in small amounts, but on the other hand, because they have high reactivity, some of them decompose during melt-kneading, causing the so-called " There were problems such as "staining", easy yellowing, and lack of thermal stability. From this point of view, the present inventors have already proposed a heat-stabilized flame-retardant polyolefin composition containing etherified bisphenol tetrabromide, antimony trioxide, and a metal salt of a higher fatty acid (Japanese Patent Publication No.
−25061). That is, the above proposal has greatly improved the thermal stability of heat-retardant polyolefin compositions. However, such flame-retardant polyolefin compositions may still not have sufficient thermal stability depending on the type of extruder or injection molding machine and the shape of their screws. [Means for Solving the Problem] The present inventors conducted further intensive research on the flame-retardant polyolefin composition as described above, and found that the composition of the flame-retardant polyolefin contains an aliphatic carvone having a melting point of 60°C or less. The present invention was developed based on the knowledge that it is very effective in improving the thermal stability of objects and is also effective in preventing the blooming phenomenon (whitening phenomenon) in molded products. That is, in the present invention, based on 100 parts by weight of polyolefin, the general formula: (However, R ₃ and R ₄ are alkyl groups having 2 to 10 carbon atoms bonding at least two bromine atoms of the same or different types.) Etherified tetrabromide bisphenol S represented by the general formula, (However, R ₅ , R ₆ and R ₇ are alkyl groups having 2 to 10 carbon atoms bonding at least two bromine atoms of the same or different types.) This flame-retardant polyolefin composition contains 0.5 to 30 parts by weight of one kind of organic halogen flame retardant and 0.01 to 5 parts by weight of an aliphatic carboxylic acid having a melting point of 60°C or less. The present invention also provides a flame retardant polyolefin composition comprising 10 to 100% by weight of antimony trioxide based on the organic halogen flame retardant in the above composition. In the present invention, it is possible to obtain a flame-retardant polyolefin composition that exhibits good thermal stability during melt-kneading and is less likely to be colored or so-called "scorched" due to decomposition. Furthermore, this composition prevents the blooming phenomenon that precipitates on the surface of the molded article and deteriorates the appearance of the molded article due to the flame retardant and various additives blended therein. The polyolefins used in the present invention include homopolymers of α-olefins such as ethylene, propylene, and butylene, random copolymers of α-olefins and other α-olefins, block copolymers, and mixtures thereof. In particular, polyolefins containing polypropylene as a main component are preferably used. The general formula for organic halogen flame retardants is: (However, R ₃ and R ₄ are alkyl groups having 2 to 10 carbon atoms bonding at least two bromine atoms of the same or different types.) Etherified tetrabromide bisphenol S having the general formula; (However, R ₅ , R ₆ and R ₇ are alkyl groups having 2 to 10 carbon atoms bonding at least two bromine atoms of the same or different types.) Brominated alkyl isocyanurates selected from the group consisting of One type of organic halogen flame retardant is used. The amount of the organic halogen flame retardant to be blended is 0.5 to 30 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight of the polyolefin. When the amount of the organic halogen flame retardant is less than the above lower limit, a sufficient flame retardant effect cannot be exhibited, and when it is more than the above upper limit, thermal stability deteriorates, which is not preferable. In addition, fatty acids with a melting point of 60°C or less include saturated fatty acids such as caproic acid, caprylic acid, capric acid, lauric acid, and myristic acid; unsaturated fatty acids such as oleic acid, erucic acid, and elaidic acid, but especially saturated fatty acids. Fatty acids are preferably used. The amount of the fatty acid having a melting point of 60° C. or lower is 0.01 to 5 parts by weight, preferably 0.03 to 3 parts by weight, based on 100 parts by weight of the polyolefin. If the blending amount of the fatty acid with a melting point of 60°C or lower is less than the lower limit above, a sufficient thermal stabilizing effect cannot be achieved, and if it is higher than the upper limit above, it may be difficult to produce polyolefin molded products. The problem is that it is too slippery, making it impossible to produce stable molded products. The present invention achieves a highly flame-retardant polyolefin composition by further blending antimony trioxide with an organic halogen flame retardant and an aliphatic carboxylic acid having a melting point of 60°C or lower. . The amount of antimony trioxide is generally 10 to 100% by weight based on the organic halogen flame retardant.
It is. In the present invention, the mixing order of polyolefin, organic halogen flame retardant, aliphatic carboxylic acid having a melting point of 60°C or less, and antimony trioxide is not particularly limited, and each component may be mixed at the same time, or several types may be mixed. The ingredients may be mixed in advance and the rest may be mixed later. The mixing method is also not particularly limited, and is generally carried out using a tumbler blender, a V-type blender, a Henschel mixer, a ribbon mixer, or the like.
Furthermore, several types were mixed in advance with a Henschel mixer,
Next, the remaining ingredients may be added and mixed in a tumbler, but the mixing order and device may also be changed. The polyolefin composition of the present invention is based on the following components: a polyolefin, the organic halogen flame retardant, an aliphatic carboxylic acid having a melting point of 60°C or less, and antimony trioxide; however, in addition to these components, If necessary, conventionally known stabilizers, colorants, antistatic agents, lubricants, such agents, etc. may be added. [Actions and Effects] The flame-retardant polyolefin composition of the present invention has high thermal stability and blooming resistance. The reason why such a high degree of thermal stability is obtained is not clear, but the polyolefin composition of the present invention melts the carboxylic acid first in the extruder.
It is presumed that the flame retardant and polyolefin create a state in which they can easily mix uniformly, thereby preventing the flame retardant from being present in high concentrations locally. In addition, flame-retardant polyolefin compositions are generally
In addition to heat retardants, they often contain various substances such as the above-mentioned additives. Among these, they precipitate on the surface of molded products and cause a blooming phenomenon (whitening phenomenon).
may occur. In the flame-retardant polyolefin composition of the present invention, since the blended aliphatic carboxylic acid has a low melting point of 60°C or less, it migrates to the surface of the molded product of the polyolefin composition, exhibiting the phenomenon of lowering the melting point, and causing blooming. It is assumed that this will have the effect of preventing this phenomenon. [Examples] In order to explain the present invention more specifically, Examples and Comparative Examples are given and explained below, but the present invention is not limited to these Examples. The combustion test results shown in the Examples and Comparative Examples are in accordance with UL Standard Section 94 (test piece thickness: 1/8 inch), and the yellowness measurement results were obtained using Suga's SM Color Computer SM. -3-CH was used and indicated by yellow index (YI).
The higher the yellowness, the higher the value. Example 1 Dibromopropyl etherified tetrabromobisphenol S in the proportions shown in Table 1 to 100 parts by weight of polypropylene (PN640 manufactured by Tokuyama Soda Co., Ltd.),
(Nonene vPR-2 manufactured by Marubishi Yuka) An aliphatic carboxylic acid, an aliphatic carboxylic acid metal salt, antimony trioxide, and a heat stabilizer were mixed in a super mixer. The heat stabilizer is 2,6-di-tert-butyl-4
- 0.1% and 0.2% of methylphenol and dilaurylthiopropionate in the total composition, respectively;
It was added so that Next, the mixture was melt-kneaded and pelletized using a 40 m/m extruder. This pellet was molded using a 20Z injection molding machine to obtain a combustion test piece and a color plate for color measurement. Combustion test (UL standard) using this combustion test piece
Sb94) and the results are also listed in Table 1. In addition, the color plate for color measurement was measured with a colorimeter manufactured by Suga Co., Ltd. to obtain yellowness index (YI). These results are also listed in Table 1. Furthermore, after leaving this colored plate in a dust-free state (40°C) for 3 months, the surface was observed to determine whether there was any blooming phenomenon. This result is also the first
Also listed in the table.

【table】

[Table] * corresponds to a comparative example.
Example 2 The flame retardant, fatty acid, fatty acid metal salt, and antimony trioxide shown in Table 2 were added to 100 parts by weight of polypropylene (PN240 manufactured by Tokuyama Soda Co., Ltd.) in the proportions shown in Table 2. An experiment was conducted in the same manner as in Example 1, and the measurement results of flame retardant and yellowness were obtained. These values are also listed in Table 2.

[Table] * corresponds to a comparative example.

Claims (1)

[Claims] 1. For 100 parts by weight of polyolefin, general formula, (However, R ₃ and R ₄ are alkyl groups having 2 to 10 carbon atoms bonding at least two bromine atoms of the same or different types.) Etherified tetrabromide bisphenol S represented by the general formula, (However, R ₅ , R ₆ and R ₇ are alkyl groups having 2 to 10 carbon atoms bonding at least two bromine atoms of the same or different types.) A flame-retardant polyolefin composition comprising 0.5 to 30 parts by weight of an organic halogen flame retardant and 0.01 to 5 parts by weight of an aliphatic carboxylic acid having a melting point of 60°C or less. 2 For 100 parts by weight of polyolefin, general formula, (However, R ₃ and R ₄ are alkyl groups having 2 to 10 carbon atoms bonding at least two bromine atoms of the same or different types.) Etherified tetrabromide bisphenol S represented by the general formula, (However, R ₅ , R ₆ and R ₇ are alkyl groups having 2 to 10 carbon atoms bonding at least two bromine atoms of the same or different types.) 0.5 to 30 parts by weight of one kind of organic halogen flame retardant with a melting point of 60
A flame-retardant polyolefin composition comprising 0.01 to 5 parts by weight of an aliphatic carboxylic acid having a temperature of 0.degree.