CS226409B2 - Fireproof polystyrene compositions - Google Patents

Abstract

A self-extinguishing polystyrenic composition comprising a polystyrenic resin, a fire-retardant amount of a halogenated organic fire-retardant agent and a nitrogen-containing organic compound selected from amines, amides and ammonium compounds containing from 20 to 40 carbon atoms and their mixtures, the nitrogen-containing compound being used in an amount of from 0.5 to 50% based on the weight of fire-retardant agent.

Description

The present invention relates to non-flammable polystyrene compositions.

Polystyrene blends containing polystyrene, styrene-acrylomiril or SAN copolymers, acrylonitrile-butadiene-styrene copolymers, or ABS, polystyrenes containing rubber with improved impact strength, may be flame-retardant for many uses, or at least may contain flame retardants. For simplicity, its components will be referred to as "flame retardants".

The most commonly used flame retardants are organic compounds containing bromine and / or chlorine. However, in order to obtain polystyrene compositions having desirable self-extinguishing properties, it is necessary to use a considerable amount of flame retardants, which is detrimental to other properties of such compositions, such as tensile strength, thermal stability.

In order to reduce the amount of flame retardant additives required to obtain polystyrene mixtures meeting the required standards in terms of flammability and flame spread, the synergistic effect of other additives or organic agents which used in the absence of halogenated compounds have virtually no flame retardant effect was studied or spreading flames. Nitrogenous organic compounds and 'organic peroxides' have been suggested as synergistic agents, but these have some unsuitable 'properties', particularly in terms of 'toxicity and stability'.

The present invention provides non-flammable polystyrene compositions comprising a styrene polymer and a flame retardant based on halogenated compounds in combination with nitrogenous organic compounds.

The invention is that the flame retardant polystyrene composition of the invention comprise a nitrogen-containing organic compound selected from the group consisting 'amines, amides, or ammonium compounds having 20 to 40' carbon atoms, and the 'mixtures thereof, in an amount of 0.5 to 50 ^iO % by weight based on the halogenated flame retardant.

The term "styrene polymer" means not only homopolymers such as crystalline polystyrene but also styrene copolymers such as SAN and ABS resins as well as impact resistant polystyrenes, which may contain up to 15% by weight of rubber. The invention applies to expandable styrenic polymers prepared either by forming expandable beads or by extrusion (extrusion) of a mixture of styrenic polymers and blowing agents. In addition, it has been observed in the extrusion of styrene polymers, the blowing agent and the organic nitrogen compound. The dimensions of the occluded air cavities in the formed multi-cellular product were clearly smaller than those obtained by the prior art. For example, in the presence of the quaternary alkylammonium chloride of. According to the invention, the average ¹ dimensions of the cavities are between 80 and 100 micrometers, while without addition of the nitrogen compound they have at least 200 micrometers. It follows that the obtained mul. ticelulární. . pieces (parts, workpieces) have lower density and better self-extinguishing properties, which is particularly interesting for many applications.

The halogenated flame retardant used in the polystyrene blends of the invention is most often an organic chlorine and / or bromine compound. The additive is used in an amount such that the halogen content of the final product is greater than 0.2 percent by weight. Content greater than 15 percent ... does not yield. none. advantage ... Generally, the halogen content of the final product is preferably between about 0.5 and about 0.5 to about 0.5 to about 0.5 to about 0.5 to about 0.5 to about 0.5 to about 0.5 to about 0.5. 10%. weighting. It depends in particular on the type of halogen; the accumulated compounds are generally more potent than the corresponding chlorinated derivatives and can therefore be used in smaller amounts. .Me- ^; halogenated flame retardants. most often. used ... is ...... maybe we are -........

acetylene tetrabromo derivative, ethano halogene derivatives such as dibramtetrachloirethain, tetrachloroethane, pentachloroethane, tetrabromobutane, hexachloro- or hexabromobenzene, polyhalobifeinyls, polyhalobiphenyl ethers, perhalopentacyclonododecane or mixtures thereof, penthalobentacyclododecane, pentachlorobutane, pentachloroethane, pentachloroethane, pentachloroethane, pentachloroethane, pentachloroethane;

. Nitrogenous. The compounds of the invention potentiate clearly. activity of halogenated compounds. used ’. as a means. . flame retardant. These. the nitrogenous compounds are. Amines, amides, or aimonium compounds containing around. 20 to around. 40 carbon atoms, preferably 26. to. 40 ··. atoms. carbon. v. molecule. . . These nitrogen compounds. are. particularly. effective and generally. used in quantities that. se. varies between about 0.5 and. 50% by weight of the additive. flame retardant. This. quantity depends. on . type. flame retardant and type used. nitrogenous compounds. In most cases, the synergistic agent can be used in an amount. between 0.01% and 5% by weight, preferably between about 0.02 and 2% by weight, based on the polystyrene resin.

The choice of nitrogen compound depends in particular on its cost and availability. In this respect, the most interesting nitrogen compounds are also secondary and tertiary amines of general interest

Ri /

of formula N — R2 \

R 3 wherein R 1 represents a hydrogen atom or an alkyl radical of 9 to 18 atoms. carbon and

R 2 and R 5 are the same or. are different alkyl radicals having 9 to 18 atoms. carbon, or

(b) fatty amides. acids of up to 25 carbon atoms, such as ethylene-bis-stearylamide, or.

c) ammonium compounds such as

Cj) alkylpyridinium bromides. of the general formula

wherein R 4 is an alkyl radical with at least 15 α-. tomy. carbon, or ......

(C) quaternary ammonium compounds of the general formula

wherein X represents a chlorine or bromine atom, or an alkyl sulfate, and wherein R 5 to R 5 denote α-. or a C 1 -C 18 alkyl group, the total number of carbon atoms. these· . residues. is at least 20. Among the ammonium compounds that are suitable is. compounds of which: (1) R5 and R7 are methyl; R6 denotes an alkyl residue containing at least 9 carbon atoms; such as lauryl or stearyl; ’Re is. identical to R6 or is a benzyl residue; and X. is chlorine or bromine;

. . ’. 2) R 5 and R 7 denote methyl. residues; Re marks. a dialkyl ienoxy-ethoxyethyl radical, preferably diisobutyl-phenoxy-ethoxyethyl; R 5 represents a benzyl radical and X represents a chlorine or bromine atom.

3) R 5 and R 7 denote methyl radicals; R6 represents an alkyl radical having at least 4 carbon atoms, such as butyl or hexyl; R 5 represents a hydrogen atom; and X represents an alkyl sulfate group having an alkyl radical of at least 12. . Carbon atoms, such as lauryl or steoiryl.

The nitrogenous compounds of the present invention can be absorbed into. a mixture of inexpensive mixing of the styrenic polymer, a flame retardant and a nitrogenous compound, optionally with other conventional additives such as colorants, lubricants, etc. It is also possible. to add these nitrogenous compounds. to the monomers prior to polymerization.

Certain flame retardant additives which have increased thermal stability are preferably used in admixture with antimony oxide. It has been found that the combined use of the nitrogen compound allows to reduce about 50% of the amount of antimony oxide added to the polystyrene blend compared to the same quality of self-extinguishing the final product. This amount, depending on the type and amount of the flame retardant, does not generally exceed 7% by weight of the styrene polymer; it is most often present in an amount of between 2 and 5%. For other flame retardant additives, most often consisting of aliphatic halogen compounds, the addition of antimony oxide is not necessary.

The present invention is illustrated by the following non-limiting examples.

The self-extinguishing properties are determined on samples of dimensions 12.70 X 1.27 X 0.32 cm. The sample is suspended in such a way that its largest dimension is vertical and its lower edge is 0.95 cm above the upper edge of the burner. The burner is then ignited and adjusted so that the flame is 1.9 cm high; the air is mixed until the yellow point at the top of the flame disappears. This flame

Synergic agents

Stearyldimethylbenzylammonium chloride Distearyldimethylammonium chloride Dilauryldimethylammonium chloride Diisobutyl-phenoxy-ethoxy-ethyldimethyl-benzylammonium chloride monohydrate Cetylpiridinium bromide

Ethylene-bis-stearylamide Distearylamine Trilaurylamine

The hexyl dimethyl stearyl ammonium sulfate is placed below the lower edge of the sample along its axis. The flame is left for 10 seconds. At that point they are removed and the burning time of the sample is measured. Once the combustion of the sample has stopped after the burner has been removed, the burner is immediately re-positioned for 10 seconds. The burner is removed again and the burning time is measured. The values given in the examples are the average of twenty consecutive measurements (10 test samples and two measurements for each sample). The same method is used for expanded polystyrene, but the sample is placed above the flame for only 3 seconds.

In the examples, the percentages given are by weight based on the weight of the styrene polymer.

Example 1

A mixture containing crystalline polystyrene, 0.75% pentabromochlorocyclohexane, 0.05% di-tert-butylhydroxytoluene (BHT), 0.035% zinc stearate, and 0.20% synergists listed below was prepared.

The average burn times were as follows:

Average burning time (in seconds)

0 “42 0“ 44 023

0 “51 2“ 07 0 “87 0“ 54 0 “80 0“ 44

The same mixture, but without the synergistic agent, had an average burn time of 11.71.

Exemplary polystyrene, a halogenated flame retardant, 0.05% BHT, 0.035% zinc stearate, dilauryldimethylammonium chloride as a synergistic agent.

The mixture containing crystals was colored. The average burn times were as follows:

Flame retardant Synergic agent Average burning time Type and quantity quantity in% (in seconds) Tetrabromacetylene (0.75%) 0.20 0.49 DibiΌmtetrachloroethane (0.75%) 0.20 1.24 Pentachloroethane (0.75%) 0.10 9.17 Tetrabromobutene (0.75%) 0.05 1.58

Example 1 and d 3

A blend was prepared containing impact resistant polystyrene (containing 6% rubber), 0.05% BHT, 0.035% zinc stearate, halogenated flame retardant, dilauryldimethylammonium chloride as a synergist, and antimony oxide.

Flame retardant Type and quantity ^Sb 2 ^O 3 Synergicant% Average burning time (in seconds) Hexabromobenzene (10%) 3 0.05 1.24 Polybromodiphenyl ^(10!%) 3 2.00 0.97 Perchlorpentacyclodecane (15%) 3 2.00 1.12 Perchlorpentancyclododecane (10%) 3 2.00 3.17

Example 4

Polystyrene was prepared by slurry polymerization with the addition of 1% pentabrommonochlorocyclohexane and 0.15% distearyldlmethylammonium chloride to styrene. After polymerization, the polystyrene beads are washed with water, and then treated overnight in vacuo at 75 ° C.

Samples of this polymer were subjected to the tests described above. An average burning time of 0 “46 was found.

Example 5

A mixture of polystyrene with impact resistance (containing 5% rubber), 10% decabromodiphenyl, 3% Sb ₂ O ₃ and 0.50% trilaurylamine was prepared.

The average burning time was 1 "10.

The same mixture, but without the "heavy" amine, had an average burn time of 2.18 seconds.

Example 6

Expanded polystyrene samples were prepared by injection molding expandable polystyrene beads (containing pentane as an expansion agent) to which 1.5% pentabrommonochlorocyclohexane and 0.2% dilauryldimethylammonium chloride were added.

The average burning time was 0.70 seconds (as opposed to 3 21) without the addition of an ammonium compound).

Example 7

Was ready . a sample of expanded polystyrene by extrusion (extrusion) of polystyrene in the presence of a mixture of equal parts by weight of CF 2 Cl 2 and CFC 1, pentabrommonochlorocyclohexane (flame retardant; 3%) and distearyldimethylammonium chloride (synergist; 0.1%).

The average burning time was 1 "10. The air tubes in polystyrene had an average dimension of 80 microns and the final product density was 35 kg / m ³ .

In contrast, without the addition of a synergist, the results were as follows:

- burning time 4 “38 - average size of tubes 200 micrometers - density 39 kg / m ³

Example 8

A blend containing crystalline polystyrene, 5% chlorinated paraffin (having an average of 25 carbon atoms and a chlorine content of 70%), 0.1% BHT, 0.035% zinc stearate and 0.2% distearylmethylammonium chloride was prepared.

The average burning time was 10.6 seconds.

The same mixture, but not containing the ammonium compound, had an average burning time of greater than 60 seconds.

Example 9

A mixture of ABS resin (containing 7% butadiene and 17% acrylonitrile), 12% decabromodiphenyl ether, 5 was prepared. % Sb ₂ O 3 and 2% distearyldimethylammonium chloride.

The average burning time was 1.17 seconds.

The same mixture, but not containing the ammonium compound, had an average burning time of 3.48 seconds.

Claims (11)

SUBJECT A flame-retardant polystyrene composition comprising a polymer and a flame retardant based on halogenated compounds in combination with nitrogenous organic compounds, characterized in that as a nitrogenous organic compound containing a nitrogenous compound selected from the group consisting of amines, amides, ammonium compounds having 20 to 40 carbon atoms and mixtures thereof, in an amount of 0.5 to 50% by weight based on the halogenated flame retardant. 2. Flame retardant polystyrene mixtures according to the invention of claim 1, characterized in that they contain as nitrogen-containing organic compound a nitrogen-containing compound having 20 to 40 carbon atoms selected from the group consisting of: (a) a secondary or tertiary amine with at least one C 9 -C 18 alkyl group; (b) an aliphatic acid amide of at least 26 carbon atoms; (c) an amine compound selected from the group consisting of (1) an alkylpyridinium bromide having an alkyl group of at least 15 carbon atoms; and (2) an ammonium compound having a generic pattern of kylpyridinium bromide having an alkyl residue of at least 15 carbon atoms. 3. Flame retardant polystyrene mixtures according to claim 1, characterized in that they contain from 0.01 to 5% by weight of nitrogenous organic compound, based on the weight of the styrene polymer. 4. The composition of claim 3 comprising from 0.02 to 2% by weight of nitrogenous organic compound, based on the weight of the styrene polymer. Fifth combustible polystyrene blends according to claims 1-4, characterized in that the nitrogenous organic compound comprises a secondary or tertiary amine of formula NR1R2R3, where R ¹ - is hydrogen or an alkyl radical having 9-18 carbon atoms and R ² and R ³ are the same or different and represent an alkyl radical of 9 to 18 carbon atoms. 6. Flame retardant polystyrene mixtures according to Claims 1 to 4, characterized in that they contain as the nitrogenous organic compound an amide of an aliphatic acid having more than 25 carbon atoms. 7. Flame-retardant polystyrene mixtures according to Claims 1 to 4, characterized in that as nitrogen-containing organic compound they contain al in which: X represents a chlorine or bromine atom or an alkyl sulphate group of at least 12 carbon atoms and R 5 to R 8 are each hydrogen or C 1 -C 18 alkyl, the total number of carbon atoms in these radicals being at least 20. 8. Flame retardant polystyrene mixtures according to one of Claims 1 to 4, characterized in that they contain as a nitrogenous organic compound a quaternary ammonium compound of the formula I (I) n / +. ^R 6 ~ ^N ~ Wherein X represents a chlorine or bromine atom or an alkyl sulphate group and the groups R5 to R6 represent a hydrogen atom or a group containing 1 to 18 carbon atoms and (d) mixtures thereof, the amount of said nitrogenous compound being 0.5 to 50% by weight based on weight of the flame retardant. 9. The composition of claim 8 wherein the nitrogenous organic compound comprises a quaternary ammonium compound of the above formula (I), wherein: X represents a chlorine or bromine atom, R 5 and R 7 are each methyl and R ₆ and R 8 are each an alkyl radical of at least 9 carbon atoms, or R 8 is a benzyl radical. 10. A composition according to claim 8, wherein the nitrogenous organic compound comprises a quaternary ammonium compound of the above formula (I), wherein: X represents a chlorine or bromine atom, R5 and Rfi are each methyl, R @ 1 represents a dialkylphenoxy-ethoxyethylene radical a R 5 denotes a benzyl residue. 11. The composition of claim 8 wherein the nitrogenous organic compound comprises a quaternary ammonium compound of the above formula (I), wherein: X represents an alkyl sulfate group having at least 12 carbon atoms, R5 and R7 are each methyl, R _(; is an alkyl radical having at least 4 carbon atoms and R ₈ represents a hydrogen atom.