CS242965B1 - Thermoplastic material with reduced inflammability - Google Patents

Abstract

Thermoplastic material having low flammability, good fluidity, high resistance to conversion and low tendency to decompsn. comprises (in wt.%); impact resistant polystyrene 72-96.7; a halogenated lubricating-type flame retardant pref. hexabromo-cyclo-dodecane 3-15; an O2-contg. inorganic cpd. of B, Al, Si, Ti, Sn, V, Sb, Mo or W esp. an oxide of Sb, Al or Mo 0.1-7; an organic Hhal acceptor 0.1-5; and an antioxidant 0.1-2. Impact resistant polystyrene may be polystyrene modified with an unsatd. rubber e.g. polybutadiene or its copolymers or with a satd. elastomer e.g. ethylene-propylene rubber.

Description

The invention relates to a thermoplastic material with reduced flammability, very good flow properties, good processing stability and a markedly reduced tendency to form decomposition products.

There are several ways to reduce the flammability of organic polymers, which is an obstacle in many of their technical applications. In addition to special non-flammable coatings, the action of certain compounds, the so-called flame retardants, which are dispersed in the polymer, is usually used.

The presence of these compounds slows down or completely prevents the combustion process, using different mechanisms of action. The most commonly used chemical inhibitors are those radical reactions that are essential for the combustion process.

Compounds such as decabromodiphenyloxide, brominated biphenyls, chlorinated paraffins, optionally in combination with other synergistic additives, are examples of flame retardants already widely used commercially.

Their effective amounts are, for example, from 10 to 20% by weight for polystyrene plastics, which, in view of the high cost of the retarders, constitutes an economically demanding modification. In addition, high concentrations of mostly solid powders in the thermoplastic adversely affect some of the utility properties of the resulting material: toughness, ductility, aging resistance, and some processing characteristics deteriorate significantly.

In addition to the method of chemical combustion inhibition, the extinguishing of the burning material can also be achieved by separating the burning part by dripping the resulting melt, which at the same time takes away the heat necessary for further combustion.

Dripping of the polymer melt can only occur if the polymer has a sufficiently low viscosity at combustion temperatures. In this case, the retarder must have the character of a lubricant or must cause depolymerisation of the material at higher temperatures and thus a decrease in its viscosity. Both effects can, and often do, often apply simultaneously.

However, it is generally required that the dripping melt does not cause ignition of the object on which it falls. It is therefore desirable that, in addition to the viscosity modifier function, the added compound, which is a chemical combustion inhibitor and at the same time effectively reduces the viscosity of the polymer at combustion temperatures, may be used at a substantially lower concentration, which represents / considerable economic effect.

In addition, important mechanical characteristics of the polymer, such as toughness and ductility, are much less affected than when using retarders acting exclusively as inhibitors of radical reactions.

Said flame-quenching method is included in the classification of flammability of polymers by standardized tests, of which the very strict vertical UL-94 test is widely used. According to this test, flame retardant materials are classified primarily in category V-2.

For some applications this method of flame extinguishing is not suitable, for example for the possibility of burns by dripping melt, on the contrary, it is suitable for some special applications. The disadvantage of most retarders of this type is that the degradation reactions they induce, which are conducive to extinguishing the flame by dripping, partially already take place at the thermoplastic processing temperatures, sometimes to a considerable extent.

However, this phenomenon is completely undesirable in view of maintaining the good properties of the modified polymer. It is an object of the present invention to provide a thermoplastic material which exhibits very good processing stability and has a good level of mechanical and visual properties while maintaining limited flammability, characterized by at least grade V-2 of the UL-94 test.

A thermoplastic material with reduced flammability, very good flow properties, low processing stability and a significantly reduced tendency to form decomposition products, according to the invention, consists of 72% to 96.7% by weight, tough polystyrene plastic, 3 to 15 % by weight, halogenated flame retardant of the lubricating type, preferably hexabromocyclododecane, 0.1 to 7% by weight, of an oxygenated inorganic compound of the element group B, Al, Si, Ti, Sn, V, Sb, Mo, W, preferably antimony trioxide, of aluminum or molybdenum, 0.1 to 5 wt.%, an organic hydrogen halide acceptor, and 0.1 to 2 wt.%, a polymer chain oxidation inhibitor.

Contrary to expectations, it has been found that to stabilize the aforementioned modified thermoplastics with a flammability degree of at least V-2 according to the UL-94 test (i.e. in the presence of so-called flame retardants of the lubricating type / certain oxygen-containing inorganic metal compounds III have an extremely high efficiency. to IV. groups of the periodic table which are not otherwise used for stabilizing thermoplastics. In particular, the combination of these compounds with organic hydrogen halide acceptors and polymer chain oxidation inhibitors makes it possible to achieve extremely good processing stability of the modified thermoplastic.

Tough polystyrene plastics are polystyrenes which contain as fashion. a polyunutadiene or copolymers thereof or saturated elastomers such as ethylene-propylene rubber and the like.

By halogen-containing lubricating-type retardants is meant halogenated and alicyclic and aliphatic hydrocarbons, incompletely accumulated diphenyls and accumulated esters of phosphoric acids with aliphatic alcohols, with a melting point below 210 ° C. In addition to the usual inhibitory action on the radical reactions underlying combustion, these flame retardants simultaneously reduce the viscosity of the melt and thus promote flame quenching by dripping the melt.

It is not important what mechanism the viscosity reduction occurs at the combustion temperatures. These may be the action of these substances as an effective internal lubricant or as a depolymerising agent causing a decrease in the molecular weight of the polymer, or a combination of both mechanisms.

These include, in particular, hexabromocyclododecane, tetrabromocyclooctane, monochloropentabromocyclohexane, but also lower halogenated diphenyls, such as hexa-, octa- and nonabromodiphenyl, and of the esters tris-2,3-dibromopropyl phosphate.

Oxygen inorganic compound from the group of elements B, Al, Si, Ti, Sn, V, Sb, Mo, W is understood to include oxides, hydroxides, silicates, tungstates, molybdates, as well as more complicated oxygen-containing metal compounds such as various minerals. Typical examples of such materials are, in particular, antimony trioxide, alumina, tin oxides, titanium dioxide, hydrated aluminum or silicon oxides, molybdenum oxide, kaolin.

Organic hydrogen halide acceptors are organotin or organoantimonite compounds or the barium, cadmium, zinc, calcium or lead salts of organic acids or mixtures thereof, or combined systems of these substances with epoxide and phosphite compounds.

These are systems that are capable of neutralizing the released hydrogen halide produced by undesirable decomposition reactions of flame retardants and are often used as stabilizers for PVC.

Suitable organotin tin compounds are dibutyltin maleate, dioctyltin maleate, dibutyltin dilaurate, di-n-octyltin di (mono-2-ethylhexyl maleate), dioctyltin mercaptide, dibutyltin dilauryl mercaptide, and optionally, dibutyltin tin (dibutyltin tin), dibutyltin tin,

Exemplary organic acid salts include barium and cadmium salts of lauric acid, a mixture of calcium and zinc salts of stearic acid, barium, cadmium and zinc salts of caprylic acid, and the like.

Suitable epoxide compounds include epoxidized soybean oil, epoxystearic acid butyl ester, epoxystearic acid 2-ethylhexyl ester, phenylglycidyl ether, polycondensation products of epichlorohydrin and bisphenol A and the like.

Phosphite type stabilizers are phosphorous acid esters such as tris / nonylphenyl / phosphite, tris / isodecyl / phosphite, tris / 2,4-di-tert-butylphenyl / phosphorous / phenylethylphenyl / phosphite, 2,4-dinonylphenyl-di / 4 monononylphenyl / phosphite, tris (2,4-di-tert-butylphenyl) phosphite, di-stearylpentaerythrityl diphosphite, tetra (2,4-di-tert-butylphenyl) diphenyl-4,4'-en-diphosphonite and the like.

Inhibitors of polymer chain oxidation are antioxidants of phenolic or amine type, antioxidants with two or more types of functional groups, mixtures thereof, or combinations with sulfur synergistic additives.

Phenolic antioxidants which can be used are mononuclear, sterically shielded phenols, such as 2,6-di-tert-butyl-4-methylphenol, octadecyl-3 / 3,5-di-tert-butyl-4-hydroxyphenyl / propionate, pentamethylphenol, 2,6-dimethyl-4-pentatetracontylphenol , a mixture of phenol alkylation products with styrene and the like, or substituted polyhydric phenols such as 2,5-ditercamyl hydroquinone, hydroquinone monobenzyl ether or substituted bisphenols and thiobisphenols such as 2,2 methylene-bis-4-methyl-6-nonylphenol], 4,4 -butylidene-bis (3-methyl-6-tert-butylphenol), 4,4'-methylene-bis (2-methyl-6-tert-butylphenol), 4,4'-methylene-bis- (2,6-dimethylphenol), 2 2'-thio-bis (4-methyl-6-tert-butylphenol), 4,4'-thio-bis (3-methyl-6-tert-butylphenol) and the like, and polynuclear phenols such as 1,1,3-tris (2'-Methyl-4'-hydroxy-3-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5'-di-tert-butyl-4'-hydroxybenzyl) benzene, pentaerythritol-tetrakis (3- (3 *, 5 * -Ditert-butyl-4-hydroxy-phenyl) -propionate), 1,3,5-tris (4-tert-butyl) -5'-hydroxy-2 *, 6'-dimethylbenzyl / isocyanurate, and the like, singly or in combination, optionally in admixture with synergistic sulfur or phosphite compounds.

Examples of antioxidants with two or more types of functional groups are, for example, 1/3, 5-di-tert-butyl-4'-hydroxyphenylamino / -3,5-dioctylthio-2,4,6-triazine, di-stearyl-3,5-di-tert-butyl -4-hydroxybenzyl phosphonate and the like. ,

Examples of amine-type antioxidants are in particular: N-secbutylaniline, 2,4-diaminotoluene, N, N-diphenylethylenediamine, N, N-di-o-tolylethylenediamine, N-benzyl-p-aminophenol, N-butyryl-p-aminophenol , phenyl-beta-naphthylamine, o-tolyl-beta-naphthylamine, p-hydroxyphenyl-beta-naphthylamine, 4,4'-di-aminodiphenylamine, octylated diphenylamine, N, N-bis (1,4-dimethylpentyl) -p- phenylenediamine, N-isopropyl-N-phenyl-p-phenylenediamine- N-phenyl-N - (1,3-dimethylbutyl) -4-phenylenediamine, N-cyclohexyl-N-phenyl-p-phenylenediamine, N, N-diphenyl- p-phenylenediamine, N, N-di-o-tolyl-p-phenylenediamine, N, N-di-beta-naphthyl-p-phenylenediamine, N-phenyl-N (p-toluenesulfonyl) -p-phenylenediamine, condensation products reaction of amines with aldehydes or ketones such as aldol-alpha7-naphthylamine (condensation product of acetaldol and alpha-naphthylamine), polymer of 2,2,4-trimethyl-1,2-dihydroquinoline (condensation product of aniline and acetone), condensation products of dlphenylamine with acetone and more.

Examples of synergistic sulfur compounds are dilauryl thiodiproponate, distearyl thiodipropionate, pentaerythrityl tetrakis (3-laurylthiodipropionate) and the like. In contrast to conventional polymer materials with reduced flammability, the UL-94 grade V-2 material prepared according to the invention exhibits extremely good processing stability at relatively high temperatures, good thermo-oxidative stability, reducing harmful emissions and reducing corrosion of the processing equipment. Due to its good flow and mechanical properties, the material is particularly suitable for injection molding of large volume parts.

The advantages of the material prepared according to the invention are shown in the following examples.

He did

The blend of tough polystyrene was homogeneized at high speed and then plstered in a screw extruder. After subsequent grinding, one portion of the maleaial was used to contribute to the UL-94 test specimens, the other portion to test the thermal statbiity of the load.

The decrease in hooltvoosi was evaluated according to the UL-94 test. Assessment of thermal stttbiity of fabric. It was performed trk that martej-AL was left temperovtcim space 1гр11Лго1Ью vistozimetru .po OBU ^d s ³⁰ minutes at ²² 0C. ^In ytlačm ^é imio-known and has been read nt mutually comparable data / expressed in ttbulkách hodm ^ ltou G, i.e. grtmy maltriálu vytltčeného ZT 10 minutes přčeemž higher hodnott corresponds greater de <^ rt ^ i ^ c ^ im ^ e ^ á ^ /.

At the same time, the blood vessels were scored by visual comparison with the reference blood scale, where the original material, without the blood change, is a 1 degree degree of totally blackened streaked maltrial number.

A total of 8 polymer blends / labeled in Example 1 were prepared according to the known procedure

1- 1 to 1-8 in Table 1, which serve as comparative samples, illustrate the dramatic deterioration of the processing age in the incineration of a lubricating type (gamma-bromocyclododecane) flame retardant, as well as the antiperspirant enhancing effects. The use of poisonous materials.

Example 2

Samples according to the invention were now prepared as described in Example 1 and purified

2- 1 to 2-12. In Table II, Roman numerals are denoted by the following numerals: I - tris (2,4-ditrrutylphroylphosphite), II - 2,6-nitrithiyl-4-merylphrool, III - 1/3 *, 5 * -ditreicyltyl-4-hydrooylphene mixture - tino / oЗ, 55dioOiyУthio-2,4,6-triliio + UistrlrylthOoUproiiooate / 1: 1 / -hyrroyyphroyl (iropionol), V-octrdecyl-5'-nitrithiyl-4'-hydroyylphosphate / propionate, VI-octyl-difroylamio, VII-N, N''-diphroyl-phenylene-iodine, VII-1,1 3-tris (2'-methyl-1 '- 4-hydroxy-3' -teriiutyphenyl) butlo.

A sample of 2-10 coatings of the type (VOO) staining type was pigmented in black, and therefore the blood vessels were not evaluated. The results of evaluation II, in wander II, show that by using the combination of the compositions according to the invention, it is possible to prepare a polymer having a grade V-2 of which the heat stability in the ethanol is substantially improved compared to comparative samples with the same amount of hexafluorocycles. In the case of an optimum case, the thermal stability of the basic martial containing no flame retardant (sample 1-1 in the tube 1) is approaching.

Given that operates hrxtbromcyklododrktn jtko inner mativo will of course also in perfect sttb ^and butene in the polymer is about ^h ^ ^h ÍOomnoosi odnott G jxk ^^ ^{characterized and} DC than at ^the pattern without reerrUéru. hořenn.

He said t d 3 '.

Following popstným case 1 b ^y ly see samples prepared according to the recipe odpioiíujíií sample 2-3 / see tlbulil II / with rozdíeem that 1% carbon tntimonitého were successively dosed:

aluminum hydroxide 1% titanium dioxide 1% hydrotreated silica 1% titanium dioxide destroy 1% tungsten url 1% tin dioxide 1%

In each of these examples, the thermal stability G did not exceed 14 g / 10 minutes and the coloring of the samples was evaluated in the worst case with grade 4.

Example 4

Using the procedure described in Example 1, samples were now prepared according to the recipe corresponding to Sample 2-3 (see Table II), with the difference that instead of 7% hexabromocyclododecane samples were gradually prepared with the following flame retardants of the lubricating type:

Sample identification

4- 1

4-2

4-3

4-4 Tris / 2,3-dibromopropyl phosphate / monochloropentabromocyclohexane octabromodiphenyl chlorinated paraffin retarder

The results of the evaluation of these samples are shown in Tab. III.

Example

Following the procedure described in Example 1, sample 5-1 of the following composition was prepared:

Tough polystyrene.

hexabromocyclododecane antimony trioxide dibutyltin laurate pentaerythrityl-tetrakis / 3,5-dlterbutyl-4-hydroxyphenyl / propionate

89.85

7.0

2,0

1.0

0.15%%%%

The modified polymer was injected at various melt temperatures and the toughness and appearance properties of the test specimens were evaluated.

The results shown in Table ^Cl vs. flasher at te ^p lot ^{of y} and melts into ^the once i.e. ^{E 2 at} 45 ° C are

IV show that the polymer prepared according to · the present invention, may be ²³⁰ DEG C. ^b ez z ^{h h} oršen ^also VZ sword of ice an ^{hour and} hair ckýc ^{h t} n ^{o l} astnos square in ^{those with} JATE Sun ^ ^l.

^p trued ^and VAC ^and samples / river Tur ^{p y} 1-3 to 1 ~ ⁸ / ^Ily phenomenon in ^Z when te ^pl of ^{thee t} avenins ^{230C considerable} Né was accompanied by release polymer according to the invention visual defects, decrease toughness, and the injection irritant fumes whose formation was substantially reduced in the case of a modified one.

very

Table I

Sample identification

Ingredients

Tough. polystyrene

Hexabromocyclododecane

Antimony oxide

Dibutylrine maleate

DibuUyltin laurate

1 / 3β, 5-Diebutyl-4-yydroxyphenyaamino)

3,5-diortylthir-2,4. 6-triazine

Property Flammability according to Test Thermal Stability G 30 min at 220 ° C / Post-test staining

1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 100 ALIGN! 97 93 88 92.4 92.4 92.8 92.0 l 3 7 12 7 7 7 7 l l l l l - - 1 l l l l 0.6 - - - l l ^{l 1 1} 0, 6 ^{1 1} l l l l 1 - 0.2 - non V non IN V-2 V-2 V-2 V-2 V-2 V-2 4.8 12, % 22.4 21.5 17.6 18.6 22.5 13.2 1 5 7 12 6 8 7 8

UL-94 / g / 10 min, thermal stability

Table II

Sample identification Ingredients 2 - 1 2-2 2-3 2-4 2-5 Tough polystyrene 90.3 90.2 91.3 89.85 89.85 Hexabromocyclodecane 7 7 7 7 7 Antimony trioxide 2 2 1 2 2 Aluminum oxide - - - - - Molybdenum trioxide - - - - - Dibutyltin maleate 0.6 - - - - Dubityltin laurate - - 0.6 1 1 Ba / Cd stabilizer - 0.3 - - - Butyl ester of epoxystearic acid - 0, 3 - - - Trisnonylphenylphosphite - 0.1 - - - AND - -. - - - II 0.1 0.1 - 0.15 - III - - - - - IV - - - - 0, 15 in - - 0.1 - - VI - - - - - VII - - - - - VIII - - - - - black batch - - . - - - Properties * Flammability according to UL-94 test V - 1 V - 2 v - 2 V - 2 V - 1 Thermal stability G / g / 10 min ³⁰ m ^and the nut ^at 220 ° C / 8.5 13 10.4 12.1 13.1 Coloring after thermal test stability 2 3 4 3 3

2-6 2-7 2-8 2-9 Table 2-10 2-11 2-12 89.55 91.3 91.3 89.85 87.85 91.3 91.3 7 7 7 7 7, 7 7 2 - - 2 2 1 1 - 1 - - - - - - - 1 - - - - - - -. - - 0.6 0.6 1 0.6 0.6 1 1 - _ - - _{- - - - -}

0.3

- - -  - - 0.1 0.15 - '- - - - - 0.1 0.1 - - - - - - 0.15 -. - - - - - 0, 15 - - - - - - - _{- - -} - 2,0 _-

24.2

13.0

14.1

12.9

12.3

12.8

12.2

Table III of the sample designation

Flammability according to test

UL-9 4

Thermal stability G / g / min, 30 min at 220 ° C /

Coloring after thermal stability test

4-1 4-2 4-3 4-4 V-2 V-2 V-2 V-2 12.3 10.6 10.0 13.2 3 4 4 3

Table IV

Melting temperature during injection Noc: 2 ° C Impact toughness kJ.m ² Notch toughness kJ.m ² Sample appearance 215 87 6.7 white without defects 230 86 6.5 White without defects 245 82 5.5 in places dark smudges 260 26 4.1 partly

blackened

Claims (1)

SUBJECT OF THE INVENTION Thermoplastic material with reduced flammability, very good flow properties, good processing stability and markedly suppressed tendency to form decomposition products, characterized in that it consists of 72 to 96.7% by weight, tough polystyrene plastic, 3 to 15% by weight, halogenated retarder burning a lubricating type, preferably hexabromocyclododecane, 0.1 to 7 wt.%, an oxygen inorganic compound of the element group boron, aluminum, silicon titanium, tin vanadium, antimony, molybdenum, tungsten, preferably antimony trioxide, aluminum or molybdenum oxide, 0.1 up to 5 wt.%, an organic hydrogen halide acceptor; and 0.1 to 2 wt.%, a polymer chain oxidation inhibitor.