Use of hydroxybenzotriazole derivatives and/or hydroxy indazole derivatives as flame retardants for plastics and flameproof plastic moulded bodies

Abstract

The present invention relates to the use of N-hydroxybenzotriazole derivatives, in particular N-hydroxybenzotriazole salts and/or N-hydroxyindazoles, in particular N-hydroxyindazole salts as flame retardant for plastic materials. The present invention relates in addition to a flame-retardant plastic material molding compound which comprises N-hydroxybenzotriazole derivatives and/or N-hydroxyindazole derivatives as flame retardant.

Claims

1. A method of imparting flame retardancy to a plastic material comprising combining the plastic material with a flame retardant compound, wherein the plastic material is selected from the group consisting of thermoplastic, elastomeric, and duroplastic plastic materials; and wherein the flame retardant compound is according to the general formulae I to IV ##STR00023## or a mixture of at least two compounds of the general formulae I to IV, wherein, with each occurrence, respectively independently of each other, R.sup.1 is selected from the group consisting of hydrogen, alkyl radicals with 1 to 18 carbon atoms, partially or perfluorinated alkyl radicals with 1 to 18 carbon atoms, unsaturated organic radicals with up to 1 to 18 carbon atoms, two vicinal radicals R.sup.1 also being able to be joined to form a ring, NO.sub.2, F, Cl and Br, and R.sup.2 is selected from the group consisting of mono-, bi- or trivalent inorganic or organic cations.

2. The method according to claim 1, wherein the plastic material is selected from the group consisting of: a) polymers made of olefins or diolefins, and copolymers in the form of statistical or block structures, terpolymers, and graft polymers, b) a polymer selected from polystyrene, polymethylstyrene, polyvinylnaphthalene, styrene-butadiene (SB), styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-propylene-styrene, styrene-isoprene, styrene-isoprene-styrene (SIS), styrene-butadiene-acrylonitrile (ABS), styrene-acrylonitrile-acrylate (ASA), styrene-ethylene, styrene-maleic anhydride polymers including corresponding graft copolymers, and graft copolymers made of methylmethacrylate, c) halogen-comprising polymers, d) polymers made of unsaturated esters, e) polymers made of unsaturated alcohols and derivatives, f) polyacetals, g) polyphenylene oxides and blends with polystyrene or polyamides, h) polymers of cyclic ethers, i) polyurethanes and polyureas, j) polyamides, k) polyimides, polyamideimides, polyetherimides, polyesterimides, polyetherketones, polysulphones, polyethersulphones, polyarylsulphones, polyphenylene sulphide, polybenzimidazoles, and polyhydantoins, l) polyesters made of aliphatic or aromatic dicarboxylic acids and diols or made of hydroxycarboxylic acids, m) polycarbonates, polyester carbonates, and blends thereof, n) cellulose derivatives, o) non-thermoplastic or duroplastic plastic materials, p) epoxy resins, q) phenol resins, urea-formaldehyde resins, and melamine-formaldehyde resins, r) unsaturated polyester resins made of unsaturated dicarboxylic acids and diols, s) silicones, t) polyurethanes which are reaction products from di- or polyfunctional isocyanates and polyols, and polyureas, u) alkyd resins and allyl resins, and v) mixtures, combinations or blends of two or more of the previously mentioned polymers.

3. The method according to claim 1, wherein the compound according to the general formulae I to IV and/or the mixture of at least two compounds of formula I to IV is mixed with the plastic material, the total content of the compound according to the general formulae I to IV in the resulting mixture being 0.01 to 50% by weight.

4. The method according to claim 1, wherein the mono-, di- or trivalent inorganic cations are selected from the group consisting of Li.sup.+, Na.sup.+, K.sup.+, Mg.sup.2+, Ca.sup.2+, Al.sup.3+, Zn.sup.2+ and/or the organic cations are selected from the group consisting of nitrogen- and phosphorus-containing organic cations.

5. The method according to claim 1, wherein, with each occurrence, R.sup.1 is hydrogen and/or R.sup.2 is a mono- or bivalent inorganic cation.

6. The method according to claim 1, further comprising combining the plastic material and the flame retardant compound with at least one further flame retardant selected from the group consisting of phosphorus-containing, nitrogen-containing, inorganic, silicon-containing, boron-containing, sulphur-containing, halogen-containing, and radical-forming flame retardants, wherein the at least one further flame retardant is combined in an amount of up to 70 parts by weight relative to the totality of the at least one compound according to the general formulae I to IV and of the at least one plastic material.

7. The method according to claim 6, wherein the at least one further flame retardant is selected from the group consisting of a) inorganic flame retardants, layer silicates, organically- or unmodified double salts, POSS-(polyhedral oligomeric silsesquioxane) compounds, huntite, hydromagnesite, and halloysite, b) nitrogen-containing flame retardants, c) phosphorus-containing flame retardants, d) halogen-containing flame retardants based on chlorine and bromine, optionally in combination with Sb.sub.2O.sub.3 and/or Sb.sub.2O.sub.5, e) borates, optionally on carrier materials, f) sulphur-containing flame-retardants, g) anti-drip agents, h) silicon-containing compounds, i) radical-forming flame-retardants, and j) carbon modifications.

8. The method according to claim 1, comprising combining the at least one plastic material and the at least one flame retardant with at least one stabilizer selected from the group consisting of phenolic antioxidants, phosphites, phosphonites, aminic antioxidants, sulphur-containing antioxidants, hydroxylamines, and hindered amines, in an amount of 0.01 to 10% parts by weight, relative to the totality of the at least one compound according to the general formulae Ito IV and of the at least one plastic material.

Description

EMBODIMENTS

(1) a) Production of the Salts

Example 1: Synthesis of the potassium salt of 1-hydroxybenzotriazole (K-btaO)

(2) Analogously to the literature (L. A. Carpino et al., Applied Chemistry Int. Ed. 2002, 41, 442-445), there is added, to a dispersion of K.sub.2CO.sub.3 (29.5 g) in a 16% aqueous methanol solution (171 ml), 1-hydroxybenzotriazole (36 g) with agitation. After conclusion of the gas evolution, the mixture is agitated for a further hour and subsequently the excess K.sub.2CO.sub.3 is filtered off. The solution is concentrated on the rotational evaporator and the obtained product is recrystallised by dissolving twice in methanol and precipitation in diethyl ether.

(3) TGA: 1.6% weight loss at 40-380 C.; 73.4% weight loss at 380-390 C.; 0.2% weight loss at 390-600 C.

Example 2: Synthesis of the zinc salt of 1-hydroxybenzotriazole (Zn-btaO)

(4) Analogously to the literature (A. D. Katsenis et al., Inorganic Chemistry Communication 2009, 12, 92-96), the desired product is obtained from the reaction of Zn(ClO.sub.4).sub.2 (9.5 g) in an aqueous solution (375 ml) with two equivalents of K-btaO (8.5 g) in DMF (500 ml) after storage at room temperature as a solid.

(5) TGA: 3.3% weight loss at 40-360 C.; 92.2% weight loss at 360-370 C.; 0.3% weight loss at 370-600 C.

(6) b) Production and Testing of a Flame-Retardant Plastic Material Mixture According to the Invention

(7) The extrusions of the polypropylene samples (DOW C766-03) are effected at a temperature of 190 C. and a screw speed of rotation of 150 rpm on an 11 mm twin-screw extruder (process 11 by Thermo Scientific). The desired ratio of polymer and additives is firstly homogenised by mixing and supplied to extrusion via volumetric metering.

(8) Test pieces for the fire test are produced from the granulate at a temperature of 220 C. and a pressure of 2 t using a hydraulic 10 t press (Werner 86 Pfleiderer). For this purpose, the granulate is filled into the compression mould and this is transferred into the already preheated press. At a pressure of 0.5 t, the granulate is firstly melted for 60 s. After conclusion of the melting time, the pressure is increased to 2 t and kept constant for a further 3 min. Whilst maintaining the compression pressure, the mould is cooled to 60 C. and thereafter the test pieces are removed. The test pieces have the following dimensions: 127.512.51.5 mm according to the standard.

(9) The examples according to the invention and comparative examples contained in table 1 were tested according to DIN EN 60695-11-10 and the burning times and classification according to the standard were obtained:

(10) TABLE-US-00001 TABLE 1 Compositions in polypropylene and results of the fire test Burning times Sum of the subsequent burning times of 5 Classification test pieces with according to Composition two burnings DIN EN Example Flame retardant (in seconds) 60695-11-10 Comparative example 1 15% diethylphosphinate >200 Not classified (state of the art) aluminium Comparative example 2 20% diethylphosphinate 170 Not classified aluminium Example 1 according to 15% diethylphosphinate 33.8 V-2 the invention aluminium + 2% Zn salt Example 2 according to 15% diethylphosphinate 2.0 V-2 the invention aluminium + 2% K salt Example 3 according to 8% diethylphosphinate 26.8 V-2 the invention aluminium + 2% K salt Example 4 according to 8% diethylphosphinate 53.5 V-2 the invention aluminium + 2% Zn salt Example 5 according to 8% phosphonate + 2% K salt 8.7 V-2 the invention

(11) Diethylphosphinate aluminium (Exolit OP 1230, manufacturer: Clariant SE):

(12) ##STR00021##

(13) Phosphonate (Aflammit PCO 900, manufacturer: Thor GmbH) corresponding to the following structure:

(14) ##STR00022##

(15) The examples according to the invention are self-extinguishing after removing the ignition source and have, surprisingly, reduced burning times relative to the comparative example, a classification according to V-2 is awarded.

(16) New flame retardants and new flame-retardant compositions are proposed, which, because of the thermal stability and salt structure thereof, allow expectation of advantages relative to current products, such as e.g. low migration behaviour, reliable incorporation, long term stability.