DE2815035A1 - FLAME RETARDANT PLASTICS - Google Patents

Description

NOBEL SHARES EQUIPMENT Troisdorf, district Cologne

Flame retardant plastics

I Thermoplastic polyesters such as polyethylene terephthalate and poly [ butylene terephthalate] have recently become widespread! found, and especially polybutylene terephthalate has proven itself because of numerous good properties such as easy processing. .Crystallization, gate impact strength, hardness and Na'igejnauigkeii; The moldings made from it acquire considerable hardness shares, '. Due to its good electrical properties, it is also used in large areas of application in the electrical industry.

Like the majority of thermoplastics, they also have j the thermoplastic polyesters have the disadvantage that they burn easily so that their use is restricted in some cases; or is not possible. There has been no lack of attempts to

■ like polyester to be made flame-retardant, and it will also be used in the

I trade various substances as additive flame retardants f-'ir I offered polyester. The demands made on such a flame I Protective means are provided, but are so diverse that so far

no satisfactory solution to the problem is known. For ^one example, a well-suited for polybutylene terephthalate (PBT) 'flame retardants can the appearance and physical and chemical

I do not see properties of the polyester deteriorate. It may • do not diffuse out of the compound and either up-

■ are lost due to its vapor pressure, with which also the protective effect of the plasma would get lost, or on the surface of the Fornikör—

¹ per form a topping, i.e. chalk out. Such shaped bodies are completely unusable, especially for the electrical industry. Is a condition for a suitable flame retardants also have sufficient thermal stability, so that the high 7 Series ^r;: - beitungstemperaturen of Compounds 240-300 ⁰ C without ^I-ER: reduction can withstand and also later in the practical use of the?

_ 3 -

Molded body withstands elevated temperatures over a long period of time without decomposing or giving rise to discoloration. In the end the price of the flame retardant must not exceed certain limits.

Brominated diphenyls are particularly useful as additive flame retardants or diphenyl ethers, but also numerous other bromine or halogen-containing ones Connections have been suggested. Almost all of these compounds chalk out, and almost all of them degrade the properties of PBT, for example, are considerable and lead to embrittlement, so that they are of little use for reinforced PBT, but practically useless for unreinforced PBT.

It has surprisingly been found that these disadvantages can be avoided if homopolymers or copolymers are used as flame retardants on the basis of methyl tetrahalogen benzyl esters of Structural formula I

H, C Ep,

Il
CH ₂ -OCC-CH ₂ (I),

x i

j is used, where R is a hydrogen atom or a methyl group and j is X = Br or optionally Cl. Per formula unit should! at most one Cl may be present, but there is generally only 0.3 Cl, usually only 0.1 Cl instead of Br ar.i aromatic nucleus present.

These polymers are described in German patent application P 28 00 020.6.

It has been found that these polymers and copolymers are a have high thermal stability, which is considerably higher than that of the known bromine-based flame retardant, and at the processing temperatures of the thermoplastic polyester undecomposed mix in and form compound moldings even several times Let thermoplastic process without aa3 discoloration or other DecompositionGerschoirumgen on tr nt on. For others, they cause new flame retardant a good flame retardancy and very good

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OQI

Also for other high-melting plastics with high processing temperatures or plastics used at elevated service temperatures such as polyethers, polyacetals, polysulfones, Polyimides, polycarbonates, polyphenylene sulfide, polyaryl esters the new flame retardants can be used without any signs of decomposition or discoloration.

In addition, the flame retardants can also be used for any plastics that are difficult to ignite, in particular if the aspect of maintaining good material properties is important, for example in the case of polyolefins such as polyethylene, Polypropylene and polybutylene, polyacrylates and polymethacrylates, polyacrylonitrile, polystyrene and the mixed and terpolymers from the latter, such as those from acrylonitrile or Hothaoryiaten along with butadiene and styrene.

The halogen content of the flame retardants can be 40 to about 65 wt .- ^, especially 40 to 60 wt .-% in the case of the ITor.opolymerisate; in the case of the copolymers, the halogen content is about 20 to 45 % by weight.

Furthermore, the copolymers with contents of the formula unit given above can also be used themselves as plastic raw materials or as part of the plastic raw materials. The type of plastics is therefore not restricted per se. However, the addition of flame retardants, many of which are themselves powdered thermoplastics, to thermoplastics is particularly advantageous. For high-melting plastics or plastics to be processed at high temperatures, in particular thermoplastics, the flame retardants are of particular value as substances of comparably high thermal resistance.

The invention therefore flammhenisend equipped plastics esters as flame retardant component acting Hoisopolymerisate or copolymers based on methyl-tetra- 'halogenbenzy! · The structural formula I

fl

CH ₂ -OCC = CH ₂

X 'R

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contain, wherein R is a hydrogen atom or a methyl group and X = Br or optionally Cl.

Another subject are especially plastics, in which the plastic is a high-melting plastic or to be processed at high temperatures, and especially plastics in which the plastic is a thermoplastic high-melting polyester.

The plastics can use "advantage synergistic substances such as antimony or boron compounds, preferably antimony trioxide, in amounts of from 2 to 12, preferably 4 to 7 wt .-% by weight. A flame-retardant plastics with contents of fillers and reinforcing materials in amounts of 2 to 60 , preferably 10 to 40 wt .-% are a particular aspect of the invention.

Preferred fillers and reinforcing materials are all types of glass fibers.

Glass fibers as fillers and reinforcing materials are special Value for flame-retardant thermoplastic high-melting polyesters, especially polybutylene terephthalate and polyethylene terephthalate .

All percentages refer to the total amount of the plastic compound or the plastic.

The incorporation of this flame retardant ε; which comes as a fine powder is present, can be done by known methods that it, optionally together with synergists and other additives, mixed with the plastic in a suitable mixing container and then the mixture of thermoplastic processing but it can also be added to the plastics during the polycondensation "or polymerization, without it being disruptive in the action process intervenes.

The new flame retardant has a particularly minor influence on the properties of the plastics made flame retardant with it. While it is in additional amounts of 6 to 12, preferably 3 to 10 Gev /.->? with a synergistic substance such as Sb ₀ O-, in reinforced and unreinforced PBT, already offers excellent flame retardancy, as it is based on the method of Underwriters Laboratories

909842/0189

Subject 94- the best achievable value VO is measured are the mechanical values of the plastic e.g. those measured according to DIU 53 453 Impact strength values for the inventions equipped Compounds hardly worse than those that are not flame retardant equipped! products so that the flame retardant with very good success can be used not only in filled or reinforced PBT, but also in unreinforced material without the To influence mechanical properties in an unauthorized manner.

In a corresponding manner, the property values are also impaired to an unusually small extent in the case of other plastics. The substances made flame-retardant in this way, especially the high-melting plastics, are particularly suitable for use in the electrical industry, in electrical apparatus construction, e.g. for switch housings, in insulation technology and for similar applications. fertilize suitable as the flame retardant with PBT is very well tolerated and moldings thus even have an increased weight loss after 28 days storage at 15O ⁰ C neither a chalky covering. The flame retardancy measurements in reinforced or filled plastics, in which the flame retardant finish is known to be more difficult than the wicking effect of the fillers and reinforcing materials, also show particularly good results

with unreinforced masses.

j Unless otherwise indicated, percentages of quantities relate to on percentages by weight.

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example 1

A polyacrylate of the formula I with a bromine content of 64.6 Gev.-.-. 'Ä is in an amount of 9 wt .-% and 4 wt .-% SbpO ^ in as much polybutylene terephthalate with a reduced viscosity of I ^ red 1.48 dl / g mixed in cold so that the total amount is 100 % . The mixture is processed into a strand in a twin-screw extruder (ZDSK from Werner & Pfleiderer) at 260 ° C. and the strand is granulated. Test specimens 1.6 × 12.7 × 127 mm in size, as prescribed for the UL 94 fire test, are injected from the granulate. In addition, standard small items for measuring the impact strength according to DIN 53 4-53 are injected. The following measurement results are obtained:

UL 94: VO / V1 (i.e. when fresh: VO; after 7 days

Storage at 150 ⁰ C: V1) storage test for 28 days at 15O ⁰ C: No discoloration,

Weight loss: 0.3%, rating: no Impact strength according to DIN 53 453

at 23 ⁰ C: 10 samples not broken

at 0 ⁰ C: 7 samples not broken,

3 samples broken.

A comparison test with pure PBT of the same viscosity results in a weight loss of 0.15 % ^{after storage at 150 ° C. for 28 days.} The impact strength test according to DIK 53 453 shows at 23 ⁰ C: 10 samples not broken, at 0 ⁰ C: 10 samples not broken. ,

Example 2

A polyacrylate of the formula I with a bromine content of 53.0 Gev .- '/ o ι and a chlorine content of. 5 ^ wt .-% (produced according to j Example 3 of patent application P 23 00 020.6, starting from j p-Kethyltetrabro: ubensylchlorid) is in a mixer with Sb ^ ₁ O ₇ , 6 irim gals short fibers and PBT granules according to the following recipe

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56 wt .- # PBT i ^ red 1.53 dl / g 50 wt .- y & glass fibers
10% by weight polyacrylate
4% by weight SboO- ,.

After mixing, a single screw extruder (R 4-5 from Reifenhäuser) produced strand pellets and injected them into test specimens as in Example 1. The measurements carried out according to Example 1 have the following results:

UL 94-: VO / VO

Storage test over 28 days at 150 ^° C.: no discoloration.

Weight loss: 0.2 % Chalking: no.

Impact strength according to DIN 53 4-53

at 23 ^° C: 30.7 ²

at O ⁰ C: 31.2 KJ / m ²

A comparison test with pure PBT of the same viscosity and 30 % glass fibers results in a weight loss of 0.1 % ^{after storage at 150 ° C. for 28 days.} The impact strength according to DIN 53 4-53 is 33.0 KJ / m ² at 23 ° C., and 36.5 KJ / m ^{2 at 0 ° C.}

Example 3

Strand granules according to Example 2 are two more quays in Single-screw extruder plasticized, and again into strand pellets processed and only then injected into test specimens. Measurements of the impact strength and notched impact strength resulted in that, contrary to expectations, essentially the mechanical Ejgcri-ι businesses were only marginally affected.

j Despite repeated processing, the flame resistance was oei high temperature not lowered.

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example

A commercially available polyethylene terephthalate (% red 1.4 dl / g) is processed according to Example 2 to give a glass fiber reinforced compound. The measurement of the test specimens 1.6 12.7 x 127 mm in size results from TJL 94-VO / VO. Chalking does not occur even after 28 days of storage on at 15O ⁰ C.

Example 5 (comparison)

The procedure is as in Example 2, but the flame retardant used is decabromodiphenyl ether in the same amount instead of the polyacrylate. Processing is possible, and the flame test according to UL 94 also gives a good fourth. But is annealed to the moldings at 15O ⁰ C, so a clear chalky covering of Dekabromdiphenyläther be observed on the surface after one day, the increasingly strengthened in the course of annealing.

Example 6

12% by weight of a polyacrylate of the general formula I (Br content 64.6 %) together with 5% by weight of SbpO ^, both amounts based on the finished compound, are incorporated into commercially available polystyrene by known processes. Test specimens for the fire test according to UL 9 ^Z , as well as the oxygen index test (according to ASTM D 2863-70) are then produced from the compound.
V ^ is found in the UL 94 test.

The oxygen index test gives the value 23.7% by volume Op compared with 17.1 % by volume of the same polystyrene without the additives.

Example 7

The polyacrylate according to Example 1 is in Kengen from. 9,5 Gev; .-; a j z \ isa, Txr? .En. incorporated with 3% by weight of 5J> bpO ₇ a) in a polypropylene and b) in a polyacrylate. Furthermore, a polymethacrylate of the formula I with 63.2% by weight of bromine is combined in quantities of 11.0% by weight

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with polybutylene - "" elaborated.

In all cases, good results were obtained in the UL 9 ^ test xmd Oxygen Index test obtain.

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Claims (1)

Troisdorf, March 31, 1973 OZ: 78 027 (2824-) Pat ent ansT> r> i ehe 1. Flame-retardant plastics that are considered flame-retardant active component homopolymers or copolymers based on methyl tetrahalogenoenzyl esters of the structure formula I is used in which R is a hydrogen atom or a methyl group and X = Br or Gl. 2. Flame retardant plastics according to claim 1, wherein the plastic a high-melting point or one that can be processed at high temperatures Plastic is. ! 3 · Flame retardant plastics according to claim 1, wherein the plastic j is a thermoplastic high melting point polyester. j 4. Flame-retardant plastics according to one of the claims j 1 to 3, characterized by the addition of flame retardants j of the formula I in amounts of 5 to 20, preferably 7 to 12% by weight. 5. Flame-retardant plastics according to one of claims 1 to 4, characterized characterized in that synergistic substances such as antimony or boron compounds, preferably antimony trioxide, in Quantities of 2 to 12, preferably 4 to 7% by weight are added. 6. Flame-retardant plastics according to one of claims 1 to 5? ^fia ~ by gexe.A-nseicnneöjdaB them filling and 7erst;: 'r>: ur: gaotof. *? e ir. Quantities of 2 to 60, preferably 10 to 40 wt .-; "<>, are added. ι 7. Flame-retardant «plastics according to claim 6, wherein the plastic j is a thermoplastic high-melting polyester, 909842/0189