DE2458480A1 - FIRE-RETARDANT PLASTICS AND METHOD OF MANUFACTURING THEREOF - Google Patents

Description

"Fire retardant plastics and their manufacturing process"

Priority: December 10, 1973, V.St.A., No. 423 565 April 24, 1974, V.St.A., No. 463 566

The invention relates to fire-retardant plastics, in particular thermoplastic polymers, and a process for making these fire retardant plastics.

Organic polymers are used to a large extent in the manufacture used by widely used consumer and industrial items. In their usual way of making such polymers are highly flammable and combustible. Because of the fire hazard associated with their use, it has become necessary to make the organic polymer-containing agents fire-retardant. Numerous halogenated organic compounds have been proposed as fire retardants for organic polymers have been, but they have not proven fully satisfactory in their application; Although numerous halogenated ver ~

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bonds improve the fire retardancy of these polymers effect, they are usually detrimental to the properties of these polymers if they are used in sufficient quantities to convey the desired degree of fire retardancy. In addition, numerous halogenated compounds are volatile or unstable, so that such substances containing polymers lose their fire retardant properties over time. Numerous brominated compounds are found to be unsatisfactory because they have a plasticizing effect on the polymers, which is undesirable in hard plastic systems.

It has now been found that 1,1,2,3,4,4-hexabromobutene-2 is a is a very effective fire retardant for thermoplastic organic polymers.

The invention therefore relates to fire-retardant plastics, consisting of a thermoplastic organic polymer and 1,1,2,3,4,4-hexabromobutene-2 in one for one Fire retardant sufficient amount.

1,1,2,3,4 _r 4-hexabromobutene-2 of the structural formula below

Br Br Br

I I I

_Br c C == CC -Br

I Il

H Br II

combines several properties that make it valuable as a fire retardant for plastics. The connection is crystalline, melts at around 180 ° C and contains 90 percent by weight

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Bromine - because of its solid form - the compound is very useful in the case of relatively high quantities of plastics, which are often brominated by liquid organic Plasticizer effect caused by compounds is undesirable because it affects the physical and mechanical properties of the Harmful products. Because of its non-volatility, stability and insolubility in water and most common organic solvents cannot leach the hexabromobutene-2, Washing or evaporation can be removed from the plastic. In addition, the hexabromobutene-2 is non-toxic, non-irritating and biodegradable. .

1,1,2,3,4,4-hexabromobutene-2 is commercially available as a mixture consisting of about 85 to 95 percent by weight of the trans isomer and consists of 5 to 15 weight percent of the cis isomer. That trans isomer is found in water · and most organic solvents insoluble. The cis isomer is sparingly soluble in acetone and some other organic solvents. Although the cis isomer and the trans isomer separately and individually used as fire retardants in the "plastics" of the present invention can be, preferably one'aus economic and work-related Reasons to use an isomer mixture with a Content of about 90% of the trans isomer and 10% of the cis isomer.

1,1,2,3,4,4-Hexabromobutene-2 can be produced in a simple manner and in good yield by eromizing diacetylene. These Reaction can be carried out in a conventional manner and safely by contacting a gas stream containing from 20 to 40 mole percent

5 0 9 8 2 Ui 0 8 8 1

Diacetylene in an inert gas such as nitrogen with a dilute Solution of bromine in water, carbon tetrachloride or another inert solvent can be carried out. The reaction product is a mixture of polybrominated compounds, which is about 75 to 80 percent by weight 1,1,2,3,4,4-hexabromobutene-2, 15 bis 23 percent by weight 1,1,2,4-tetrabromobutene-2 and small amounts of Contains dibromobutadiene. The crystalline hexabromobutene-2 can be separated from the mixture by filtration. That on this Wise prepared hexabromobutene-2 contains 85 to 95% of the trans isomer and 5 to 15% of the cis isomer, usually about 90% trans isomer and 10% cis isomer. This mixture of isomers can can be used as a fire retardant on organic plastics without further treatment. 1,1,2,3,4,4-hexabromobutene-2 can be used to confer fire retardancy in large numbers usually flammable thermoplastic organic polymers seeds are used. Although it is for use on plastics, which are processed at temperatures below 200 ° C, is particularly advantageous, it can also be with such plastics Find use that are processed for a relatively short period at higher temperatures. Examples of such organic polymers that can be used according to the invention are polyolefins, including homopolymers and copolymers of ethylene, propylene and isobutylene, vinyl chloride homopolymers and copolymers with, for example, vinyl acetate or acrylonitrile, also vinyl acetate homopolymers and copolymers with, for example, acrylonitrile or vinylidene chloride, also polyamides, polyoxymethylenes, homo- and acrylic acid - Copolymers, which from acrylic acid, methacrylic acid, their

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Esters with alkanols with 1 to 4 carbon atoms and also acrylonitrile can be produced. Mixtures of the abovementioned polymers can also be used. Hexabromobutene-2 is particularly effective as a fire retardant in plastics that Contain polyolefins, polyvinyl chloride or acrylic resins.

Hexabromobutene-2 can be incorporated into the polymers according to customary known methods Procedures are incorporated. For example, it can be with the polymers It can be mixed in a mill or extruder, or it can be applied to the surface of molded plastic objects be applied. If necessary, it can be used for coating Polymer particles used prior to their compression or added to the monomers or the monomer mixture prior to polymerizing will. In general, finely ground hexabromobutene-2 is preferred to be added to the polymer or to the other constituents of the agent before the last compression stage.

The amount of 1,1,2,3,4,4-hexabromobutene-2, which in the polymers is incorporated is so high that · it gives the plastics the desired degree of fire retardancy without the physical properties of the agents are adversely affected. Even the addition of 5% hexabromobutene-2, based on the total weight of the agent, provides a remarkably reduced rate Burn rate. Since the compound does not act as a plasticizer, 50% and more hexabromobutene-2 can be obtained based on the total weight of the plastics used to make the

to achieve the greatest possible fire retardancy without sacrificing the properties to damage the plastics. It is generally preferred., 10 to

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25% hexabromobutene-2, based on the weight of the polymer, in both hard and flexible organic polymers use.

In addition to the organic polymers and hexabromobutene-2, the plastics according to the invention can act synergistically Compounds such as antimony oxide, fillers, pigments, dyes, Contain stabilizers, lubricants, plasticizers and other additives in the usual amounts used for such purposes »

The examples illustrate the invention.

Example 1

1,1 / 2,3,4,4-hexabromobutene-2 is used as a fire retardant in polyolefins evaluated according to the following procedure: A corresponding amount of finely divided hexabromobutene-2 is with 100 parts by weight of a commercially available polyolefin mixed. The resulting mixture is extruded into a 3.175 mm thick cable using a mixing extruder. The cable is cut into 15.24 cm long pieces. These samples are determined for their flammability by determining their oxygen limit index tested according to the procedure described in ASTM D-2863. Made of the same plastic, but without fire retardant Additional extruded samples serve as a comparison. The used Polymers, the amounts of the fire retardant added, the extrusion temperatures used and those obtained Results are given in the table below.

«· * 7 * ■

Tabel

Polymer Extrusion
temperature,
(OC) Content of
Hexabromo
butene-2
(PHR) oxygen
limit index Polyethylene lower -
density 130-135 25th 21.6 Il 130-135 10 20.8 Il 130-135 0 17.3 Polyethylene high
Density ' 150-155 25th 21.8 Il 150-155 10 19.3 It ' 150-155 0 17.5 Polypropylene 170-175 25th 21.7 Il 170-175 10 21.1 Il 170-175 0 19.2

Example 2

1,1, 2,3,4, 4-hexabromobutene-2 is used as a fire-inhibiting agent in a pliable clear polyvinyl chloride evaluated by the following method:

The following ingredients are mixed together:

Weight parts

Polyvinyl chloride (relative viscosity 2.4 (1% in cyclohexane Ba / Cd / Zn stabilizer stearic acid

Epoxidized soy dioctyl phthalate
Hexabromobutene-2

100.0

3.0

0.5

5.0

35.0

10.0

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The mixture is 5 minutes at 165.6 ° C on a two roll mixer ground and then removed from the mixer as 1/14 mm thick film. Samples cut from the film are pressed to form a film 1.8 mm thick.

The oxygen limit index of the plastic obtained is after according to the procedure described in ASTM D-2863. It is 24.1.

A comparison agent containing 45 parts of dioctyl phthalate and none of the hexabromobutene-2 has an oxygen limit index of 22.2.

A fire retardant effect can be achieved with any of the above organic polymer by incorporating a fire retardant Amount of 1,1,2,3,4,4-hexabromobutene-2 reached in the plastic will.

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Claims (9)

Claims 1. Fire-retardant plastics, consisting of a thermoplastic organic polymer and 1,1, 2, 3,4,4-hexabromobutene-2 in an amount sufficient for fire retardancy. 2. Fire-retardant plastics according to claim 1, characterized due to a content of polyolefins, vinyl chloride polymers, Vinyl acetate polymers, polyamides, polyoxymethylenes, acrylic acid resins and / or their mixtures as thermoplastic organic polymers. 3. Fire-retardant plastics according to claims 1 or 2, characterized by a content of 5 to 50 % 1,1,2,3,4,4-hexabromobutene-2, based on the weight of the polymer. 4. Fire retardant plastics; according to at least one of the preceding Claims, characterized by a content of 10 to 25% 1,1,2,3,4,4-hexabromobutene-2, based on the weight of the polymers. 5. Fire-retardant plastics according to at least one of the preceding claims, characterized by a content of an isomeric mixture of 1,1, 2,3, 4,4-hexabfombutene-2 from 90% of the trans isomer and 10% of the cis isomer. 6. Process for the production of fire-retardant plastics according to at least one of Claims 1 to 5, characterized in that a fire-retardant amount of 1,1,2,3,4,4-hexabromobutene-2 incorporated into a thermoplastic organic polymer. 7. The method according to claim 6, characterized in that polyolefins, vinyl chloride polymers, vinyl acetate polymers, Polyamides, polyoxymethylenes, acrylic resins and / or their mixtures, used as thermoplastic organic polymers'. 8. Process according to claims 6 or 7, characterized in that 5 to 50 % 1,1 / 2,3,4,4-hexabromobutene-2, based on the weight of the organic polymer, are incorporated. 9. The method according to claim 8, characterized in that one 10% to 25% 1,1,2,3,4,4-hexabromobutene-2 based on weight of the organic polymer incorporated. SO3824 / Ö881