JPS5937018B2 - Flame retardant polypropylene composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flame-retardant polypropylene composition, which has an extremely short self-extinguishing time and exhibits a high flame-retardant effect that prevents the expansion of the fire source and the spread of fire due to droplets of molten combustion material generated during combustion. The present invention provides a polypropylene composition.

In recent years, polypropylene has been widely used in fields such as electrical parts, automobile interior parts, and building materials, and as a result, polypropylene is required to have a high degree of flame retardancy.

Conventionally, as a means of imparting flame retardancy to polypropylene,
Tetrahalogenated diphenylsulfone derivatives are highly rated for their excellent durability, with extremely little oozing or shedding of flame retardants over time and temperature changes.

It is also known to improve flame resistance by adding borofluoride salt alone to polypropylene. However, although the above-mentioned polypropylene composition has self-extinguishing properties, the self-extinguishing time is very long, and it never shows satisfactory flame retardancy. As a result of various studies aimed at improving the flame retardancy of polypropylene, the present inventors unexpectedly found that when etherified tetrabrominated diphenyl sulfone and borofluoride salt were added to polypropylene, the mutual residue As a result, the self-extinguishing time can be extremely shortened, and the present invention was completed based on the knowledge that the self-extinguishing time can be further shortened by using the above two components in combination with antimony trioxide.

That is, the present invention provides an etherified tetrabrominated diphenyl sulfone having the following general formula in an amount of 7 to 15% by weight based on the total weight of the polypropylene composition (wherein R1 and R2 are at least two bromine atoms of the same or different types). 2 to 1 carbon atoms bonding
0 alkyl groups) and 1 to 5% by weight of a borofluoride salt.

The present invention also provides etherified tetrabrominated diphenyl sulfone having the following general formula in an amount of 7 to 15% by weight based on the total weight of the polypropylene composition (wherein R and R are at least two of the same or different types). 2 to 1 carbon atoms to which the bromine atom is bonded
0 alkyl group), 1 to 5% by weight of antimony trioxide, and 1 to 5% by weight of a borofluoride salt.

In the present invention, it is extremely important to add a specific amount of the above-mentioned etherified tetrabrominated diphenyl sulfone and borofluoride salt to polypropylene in combination in order to exhibit a high flame retardant effect.

As is clear from the description of the comparative examples described below, when etherified tetrabrominated diphenyl sulfone or borofluoride salt is added alone to polypropylene, the resulting polypropylene composition has a certain degree of self-extinguishing property, but The self-extinguishing time is very long, 20 seconds or more than 70 seconds. Further, even when the amount of etherified tetrabrominated diphenyl sulfone and borofluoride salt added is small, the self-extinguishing time is relatively long, 10 seconds or more, and it cannot be said that a satisfactory flame retardant effect is exhibited. However, in the present invention, etherified tetrabrominated diphenyl sulfone is contained in an amount of 7 to 15% by weight based on the total weight of polypropylene.
By specifying the amount of borofluoride salt in the range of 1 to 5% by weight, the self-extinguishing time can be reduced to 6 seconds or less for the first time.
As mentioned above, etherified tetrabrominated diphenyl sulfone and borofluoride salts are each individually known as a flame retardant or flameproofing agent for polypropylene.

However, no suggestion is made of the combined use of etherified tetrabrominated diphenyl sulfone and borofluoride salt. Even if the combination of etherified tetrabrominated diphenyl sulfone and borofluoride salt were predicted from the above-mentioned known facts, the high flame retardant effect that can significantly shorten the self-extinguishing time as shown in the present invention would not be predicted at all. It's not something you can do. That is, in the present invention, the combined use of etherified diphenyl tetrabromide sulfone and borofluoride salt exhibits an extremely synergistic effect on flame retardation; Significantly due to the specified usage of sulfone and borofluoride salts.

In addition, in the present invention, by using antimony trioxide in combination with the etherified tetrabrominated diphenyl sulfone and the borofluoride salt, the antimony trioxide acts synergistically on the flame retardant effect, resulting in extremely high flame retardant effect. Show your gender. That is, the combined use of etherified tetrabrominated diphenyl sulfone, antimony trioxide, and borofusate salt shows surprisingly excellent self-extinguishing properties in that there is no cotton ignition caused by droplets of polypropylene that occur upon contact with flames. The above effects are surprising and cannot be predicted from the effects obtained when each component is added alone or when two components are added to polypropylene. The etherified tetrabrominated diphenyl sulfone used in the present invention is represented by the general formula described above, and R1 and R
The number of carbon atoms in 2 is preferably 2 to 10, particularly 2 to 4. If the carbon number exceeds 10, thermal stability deteriorates and decomposition occurs due to heat during blending into polypropylene or when molding the polypropylene after blending, so it is not practical. Not on point.

Furthermore, the greater the number of bromine atoms bonded to R1 and R2, the better the flame retardant effect of the resulting polypropylene composition. Specifically, for example, diphenyl sulfone bis tetrabromide (dibromoethyl ether, diphenyl sulfone bis tetrabromide (dibromopropyl ether), diphenyl sulfone bis tetrabromide (dibromobutyl ether), diphenyl sulfone bis tetrabromide (dibromobutyl ether), (tribromopropyl ether),
Etherified tetrabrominated diphenyl sulfones such as tetrabrominated diphenyl sulfone bis(tetrabromobutyl ether) and tetrabrominated diphenyl sulfone bis(pentapromohexyl ether) are preferably used. Furthermore, commercially available antimony trioxide is used as is. Further, as the borofluorinated salt, alkali metal salts such as sodium salts and potassium salts, ammonium salts, etc. are particularly suitable.

In the present invention, if the amount of each component added to the polypropylene is less than the specified range, sufficient flame retardant effect of the resulting polypropylene composition as described above cannot be obtained. If the amount exceeds the specified range, the desired flame retardant effect may be maintained, but this is not preferable since it may cause coloring of the polypropylene and deterioration of physical properties. In the present invention, there is no particular restriction on the order in which each component is added to the polypropylene, nor is there any particular restriction on the timing of addition.They may be added when the polypropylene is melted;
It may also be blended into polypropylene in a solid state such as powder.

In the present invention, as the polypropylene, not only propylene homopolymers but also copolymers with other α-olefins, such as ethylene, can be used.

Furthermore, in the present invention, additives that are normally added to polypropylene, such as antioxidants, lubricants, pigments, etc., may be used in combination without any particular restriction. The polypropylene composition of the present invention exhibits an extremely high flame retardant effect, and completely prevents the expansion of the fire source and the spread of fire due to drips of melting polypropylene, which were problems with conventional flame retardant polypropylene. I can do it. The present invention will be described below with reference to Examples, but the present invention is not limited thereto.

Incidentally, in the combustion tests in Examples and Comparative Examples, the self-extinguishing time and the presence or absence of cotton ignition due to dripping were measured in accordance with the American UL test method (94 vertical method). Examples and Comparative Examples Using polypropylene with a melt index of 6 (manufactured by Tokuyama Soda Co., Ltd.), predetermined amounts of each component shown in Tables 1 and 2 were mixed and melted to obtain a polypropylene solution specified by the UL test method. A test piece (thickness: 1m7!L) was prepared.

This test piece was used for a predetermined test. The results are shown in Tables 1 and 2. The self-extinguishing time in Tables 1 and 2 is the average value of 20 times for 10 test pieces, and in Table 2, the ignition rate of cotton shows how many times it ignited for 10 test pieces. There is.

Claims (1)

[Claims] 1 7 to 15 based on the total weight of the polypropylene composition
Etherified tetrabrominated diphenyl sulfone having the following general formula in weight% ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, R_1 and R_2 are at least two of the same or different types.
Flame-retardant polypropylene composition 2 characterized in that it contains an alkyl group having 2 to 10 carbon atoms bonding bromine atoms and 1 to 5% by weight of a borofluoride salt.Based on the total weight of the polypropylene composition On the other hand, 7 to 15% by weight of etherified tetrabrominated diphenyl sulfone having the following general formula▲
There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R_1 and R_2 are alkyl groups with 2 to 10 carbon atoms that bond at least two bromine atoms of the same or different types), 1 to 5% by weight of antimony trioxide and 1 to 5
A flame retardant polypropylene composition characterized in that it contains % by weight of a fluoroborate salt.