NON-FLAMMABLE HYPOPHOSPHITE METAL SALT BASED POWDERS AND THEIR USE AS FLAME RETARDANT INGREDIENTS

Abstract

Hypophosphorous acid metal salts powders are used as flame retardant agents in flame retarded compositions suitable for polymer materials.

Claims

1. A non-flammable hypophosphite composition in powder form consisting of: a) at least Aluminium or Calcium hypophosphite b) at least a non-flammable inorganic or organic aluminium salt of phosphorus where phosphorous oxidation state is lower than +5 or a mixture thereof.

2. Non-flammable composition according to claim 1, wherein: a) said Aluminium or Calcium hypophosphite concentration is comprised from 80% to 95% by weight, b) said non-flammable inorganic or organic aluminium salt of phosphorus, where phosphorous oxidation state is lower than +5 or a mixture thereof, concentration is comprised from 20% to 5% by weight.

3. Non-flammable composition according to claim 2, wherein said non-flammable inorganic or organic aluminium salt of phosphorus, where phosphorous oxidation state is lower than +5, is an organic phosphinate aluminium salt.

4. Non-flammable composition according to claim 2, wherein said non-flammable inorganic or organic aluminium salt of phosphorus, where phosphorous oxidation state is lower than +5, is an organic phosphonate aluminium salt.

5. Non-flammable composition according to claim 2, wherein said non-flammable inorganic or organic aluminium salt of phosphorus, where phosphorous oxidation state is lower than +5, is aluminium phosphite.

6. Method of providing a flame retardant agent as non-flammable composition for organic polymer consisting of: a. at least Aluminum or Calcium hypophosphite; b. at least a non-flammable inorganic or organic aluminum salt of phosphorous where phosphorous oxidation state is lower than +5 or a mixture thereof.

7. (canceled)

8. The method according to claim 6 wherein said organic polymer is selected among: Polypropylene, Polybutylene Terephthalate, Polyamide 6, High Impact Polystirene, Acrylonitrile-Butadiene-Styrene, Polycarbonate and Polycarbonate/Acrylonitrile-Butadiene-Styrene blends.

9. Process for the preparation of the composition of claim 1, wherein components a) and b) are separately milled in powder form and subsequently added in a slow mechanical mixer or in a high-speed mechanical mixer.

10. Process for the preparation of the composition of claim 1, wherein components a) and b) are mixed before grinding.

11. Non-flammable composition according to claim 1, wherein: a) said Aluminium or Calcium hypophosphite concentration is comprised from 85% to 90% by weight, b) said non-flammable inorganic or organic aluminium salt of phosphorus, where phosphorous oxidation state is lower than +5 or a mixture thereof, concentration is comprised from 15% to 10% by weight.

Description

EXPERIMENTAL PART

Test Method for Flammable Solids

[0073] Test conditions are according United Nations Recommendations on the Transport of Dangerous Good, Manual of Test and Criteria” (Sixth revised edition, 2015), Section 33—Division4.1—Sub-section 33.2.1.4 Test N. 1: “Test method for readily combustible solids”. The ability of a substance to propagate combustion is tested by igniting it and determining the burning time. Basically, powder are loosely filled into a mold 250 mm long with a triangular cross-section of inner height 10 mm and width 20 mm. On both sides of the mold in a longitudinal direction two metal plates are mounted as lateral limitations which project 2 mm beyond the upper edge of the triangular cross section. The mold is then dropped three times from a height of 2 cm onto a solid surface. If necessary the mold is then filled up again. The lateral limitations are then removed and the excess substance scraped off. A non-combustible, non-porous and low heat-conducting base plate is placed on top of the mold, the apparatus inverted and the mold removed. The ignition source (flame from a gas burner with a minimum temperature of 1000° C.) is placed at one end until the sample ignite. A preliminary screening test is carried out. If the substance does not ignite and propagate combustion either by burning along 200 mm of the powder train within 2 min test period, the substance should not be classified as flammable solid and no further test is required. If the substance ignite and propagates burning of a 200 mm length of the powder train in less than 2 min the burning rate will be determined. A substance should be classified in Division 4.1 (readily combustible solid) when the time of burning of one or more of the six test runs is less than 45 s or the rate of burning is more than 2.2 mm/s.

Particle Size Distribution and Apparent Powder Density

[0074] Particle size measurement was performed on laser instrument (Malvern 3000). A small quantity of powder (around 0.1 gr) is introduced in the measurement cell full with absolute ethanol and submit to ultrasonication treatment for 120 seconds before measurement.

[0075] Apparent density of the powder was performed using a dry graduated glass cylinder of 100 cc (readable to 1 cc), half filled with the powder sample gently introduced without compacting. The powder density is given by the ratio between volume and weight.

Compounding and UL-94 Flammability Procedure

[0076] All components reported in Example and Comparative Example formulations are extruded in a 24 mm twin screw extruder with a temperature profile in the range depending on the polymer base. The polymer pellets are introduced in the main hopper, a dry blend of additives is introduced in the first side feeder and the glass fibres in the second side feeder.

[0077] The extruded polymer pellets are eventually dried in an oven at 90° C. before injection moulding in UL-94 specimens at different thickness (3.2 mm-1.6 mm-0.8 mm) and 5 specimens were conditioned for 24 hours at 23° C. and 50% humidity. Flammability have been reported according to UL-94 procedure. When tests do not meet V0, V1 and V2 an NC classification has been given.

INGREDIENTS

Hypophosphite

[0078] Aluminium hypophosphite (Phoslite IP-A by Italmatch Chemicals) with moisture<0.3%, PSD D98<35 microns and apparent density=0.65 gr/cc, hereafter “IP-A” Calcium hypophosphite (Phoslite IP-C, by Italmatch Chemicals), with moisture<0.3%, PSD D98<35 microns and apparent density=0.45 gr/cc hereafter “IP-C”

[0079] Non-flammable inorganic or organic aluminium salt of phosphorus, where P oxidation state is lower than +5:

[0080] Aluminium Di Ethyl Phosphinate (Exolit OP1230, by Clariant), hereafter “DEPAL” Aluminium Methyl Methyl Phosphonate, (DQFR-6006 ex Liside Chemicals), hereafter “AMMP”

[0081] Neutral Aluminium Phosphite (APA-100 ex Taihei Chemical Industrial Co. Ltd.), hearafter “NAPI”

Fillers and Reinforcing Agents

[0082] Talc (Steamic T1CA, by Imerys), a reinforcing filler, hereafter “Talc” Calcium carbonate (Omyalite 90T by Omya), a not reinforcing filler, hereafter “CaCO3”

[0083] Glass Fiber (PPG 3786, by PPG), a reinforcing filler, hereafter “GF”

Flame Retardant Agents and Synergics

[0084] Melamine cyanurate (Melagard MC25, by Italmatch Chemicals), a nitrogen containing compound, hereafter “MC”

[0085] Melamine phosphate (Melagard MP, by Italmatch Chemicals), a phosphorus nitrogen containing compound, hereafter “MP”

[0086] Melamine polyphosphate (Melapur 200/70, by BASF), a polymeric phosphorus and nitrogen containing compound, hereafter “MPP”

[0087] Magnesium hydroxide (Magnifin H10 by Huber), a metallic hydrate, hereafter “Mg(OH)2”

[0088] Aluminium hydroxide (Alcan Superfine Alcan), a metallic hydrate, hereafter “Al(OH)3”

[0089] Melamine hydrobromide (Melagard MHB, by Italmatch Chemicals), a ionic halogenated compound, hereafter “MHB”

[0090] Tetrabromo bis phenol A bis(2,3-dibromopropyl ether) CAS 21850-44-2, an halogenated aliphatic/aromatic compound, hereafter “PE68”

[0091] Decabromodiphenylethane CAS 84852-53-9, an halogenated aromatic compound, hereafter “S8010”

[0092] Brominated polystyrene CAS 88497-56-7, an halogenated aromatic polymeric compound, hereafter “BPS”

[0093] Brominated epoxy CAS 68928-70-1, an halogenated aromatic polymeric compound, hereafter “BEO”

[0094] Brominated polyacrylate CAS 59447-57-3, an halogenated aromatic polymeric compound, hereafter “BPA”

[0095] Resorcinol bis (2.6-dixylenyl phosphate) (Daihachi PX200, by Daihachi Chemicals), an organic phosphorus containing compound, hereafter “RDX”

[0096] 1,6-Hexanediamine,N1,N6-bis(2,2,6,6-tetramethyl-4-piperidinyl)-, polymer with 2,4,6-trichloro-1,3,5-triazine, reaction products with 3-bromo-1-propene,N-butyl-1-butanamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine,oxidized, hydrogenated (Tinuvin NOR371, by BASF), an oligomeric nitrogen containing compound, hereafter “NOR371”

[0097] Zinc Borate (Firebrake ZB by Borax), a flame retardant synergic, hereafter “ZnB” 2,3-Dimethyl-2,3-diphenylbutane (Perkadox 30 by AkzoNobel), a flame retardant synergic, hereafter “DICUMENE”

[0098] Aluminium Phosphate CAS 7784-30-7 by Sigma-Aldrich, a flame retardant synergic, hereafter “APA”

[0099] Ethylene Vinyl Alcohol (Soarnol DT 2904 by NIPPON GOHSEI EUROPE), a polymeric synergic, hereafter “EVOH”

[0100] Fluorinated copolymer (DYNEON MM3595, by 3M), an anti-dripping additive, hereafter “PTFE”

Polymers

[0101] Polypropylene homopolymer (Moplen HP500N), hereafter “PP”

[0102] Poly Butylene Terephtalate (Ultradur B4500, by BASF), hereafter “PBT”

[0103] Polyamide 6 (Ultramid B 22, by BASF), hereafter “PA6”

[0104] Acrylonitryile Butadiene Styrene copolymer (Magnum ABS 3904, by STYRON), hereafter “ABS”

[0105] High Impact Polystyrene (Edistir SR 550, by Enichem Versalis), hereafter “HIPS” Polycarbonate (Makrolon 2808, by Bayer), hereafter “PC”

TABLE-US-00001 TABLE 1 Powder Flammability Test in presence of Inorganics fillers and Flame retardants Hydrates (comparative examples) C.1 C.2 C.3 C.4 C.5 C.6 C.7 C.8 C.9 C.10 C.11 IP-A 100% 85% 50% 85% 50% 85% 50% 85% 50% 85% 50% Talc 15% 50% CaCO3 15% 50% ZnB 15% 25% Mg(OH)2 15% 25% Al(OH)3 15% 25% Class* F F F F F F NF F NF F NF *F = Flammable; NF = Not Flammable

Comments to Table 1

[0106] Comparison of C.2-C.3 and C.4-C.5 to C.1 shows the effect of the addition of a reinforcing filler to Aluminium Hypophosphite powder. Conclusion is that the addition of a reinforcing filler do not decrease powder flammability.

[0107] Comparison of C.6-C.7 to C.1 show the effect of the addition of an inorganic flame retardant synergic to Aluminium Hypophosphite powder. Conclusion is that the addition of an inorganic flame retardant do not decrease powder flammability at a concentration below 20%.

[0108] Comparison of C.8-C.9 and C.10-C.11 to C.1 show the effect of the addition of inorganic metal hydrates flame retardant to Aluminium Hypophosphite powder. Conclusion is that the addition of inorganic metal hydrates flame retardant do not decrease powder flammability at a concentration below 20%.

TABLE-US-00002 TABLE 2 Powder Flammability Test in presence of Nitrogen and Phosphorous containing flame retardants derivative (examples and comparative examples) C.12 C.13 C.14 C.15 C.16 C.17 E.18 E.19 E.20 E.21 C.22 IP-A 85% 85% 85% 85% 90% 90% 90% 90% 90% 90% IP-C — — — — — — 90% MP 15% MPP 15% MC 15% RDX 15% 10% NOR 371 10% OP1230 10% 10% AMMP 10% NAPI 10% APO 10% Class * F F F NF F F NF NF NF NF F * F = Flammable; NF = Not Flammable

Comments to table 2

[0109] Comparison of C.12-C.13-C.14 to C.1 shows the effect of the addition of a phosphorus nitrogen flame retardant to Aluminium Hypophosphite powder. Conclusion is that the addition of a not melting phosphorus nitrogen flame retardant do not decrease powder flammability.

[0110] Comparison of C.15-C.16 to C.1 shows the effect of the addition of an organic phosphorus containing flame retardant to Aluminium Hypophosphite powder. Conclusion is that the addition of an organic phosphorus containing flame retardant decrease powder flammability at 15% by weight but not at 10% by weight. Compositions claimed in present invention are indeed more effective than the organic phosphorus containing flame retardant and so are preferred.

[0111] Comparison of C.17 to C.1 shows the effect of the addition of an oligomeric nitrogen containing flame retardant to Aluminium Hypophosphite powder. Conclusion is that the addition of an oligomeric nitrogen containing flame retardant does not decrease powder flammability at 10% by weight.

[0112] Comparison of examples from E.18 to E.21 to C1 shows that the addition at a very low level (10% by weight) of an of organic phosphinate aluminium salt (oxidation state +1) or an organic phosphonate aluminium salt (oxidation state +3) or an inorganic phosphite aluminium salt to Aluminium Hypophosphite decrease powder flammability.

[0113] On the contrary, comparison of C.22 to C.1 show that the addition of an aluminium phosphate salt (oxidation state +5) at 10% by weight to Aluminium Hypophosphite does not affect the powder flammability.

TABLE-US-00003 TABLE 3 Powder Flammability Test in presence of Brominated additives with ionic moiety, aliphatic moiety, aromatic moiety with polymeric and monomeric structure (comparative examples) Halogen Polymeric/ Moiety Monomeric C.23 C.24 C.25 C.26 C.27 C.28 C.29 C.30 C.31 IP-A 90% 90% 90% 90% 80% 90% 80% 90% 80% MHB Ionic Monomeric 10% PE68 Aliphatic/ Monomeric 10% aromatic S8010 Aromatic Monomeric 10% BPS Aromatic Polymeric 10% 20% BEO Aromatic Polymeric 10% 20% BPA Aromatic Polymeric 10% 20% Class * NF NF NF F F F F F F * F = Flammable; NF = Not Flammable

Comments to table 3

[0114] Comparison of C.23, C.24 and C.25 to C1 show that the addition of 10% by weight of a monomeric Brominated additives, with ionic or aliphatic or aromatic moiety, reduce flammability of IP-A.

[0115] On the contrary, an higher loading (>20% by weight) of a polymeric Brominated additive (comparative examples from C.26 to C.31) is necessary to obtain a not flammable IP-A mixture.

[0116] In the Example and Comparative Example formulations, reported in the followings tables (from Table 4 to Table 8), is demonstrated that the same amount of non-flammable IP-A, according to the present invention, instead of flammable IP-A, give the same flame retardant performances, according UL 94 standard, on different polymer formulations.

TABLE-US-00004 TABLE 4 Example and Comparative Example of flame retardant formulations on PP base C.32 E.33 C.34 E.35 C.36 E.37 PP 96%  96%  93.2% 93.2% 97.8%  97.8%  IP-A 2% —   6% — .sup. 2% — E.18 — 2% —   6% — .sup. 2% MHB 2% 2% — — — — PE68 — — — — 0.1% 0.1% NOR 371 — —  0.8%  0.8% DICUMENE — — — — 0.1% 0.1% UL-94 3.2 mm V2 V2 V2 V2 V2 V2 UL-94 1.6 mm V2 V2 V2 V2 V2 V2

TABLE-US-00005 TABLE 5 Example and Comparative Example flame retardant formulations on PBT GF base C.38 E.39 C.40 E.41 C.42 E.43 PBT 50% 50% 54% 54% 55% 55% GF 30% 30% 30% 30% 30% 30% IP-A 10% —  5% —  5% — E.18 — 10% —  5% —  5% MC 10% 10% — BPA — 11% 11% 8010 10% 10% UL-94 3.2 mm V0 V0 V0 V0 V0 V0 UL-94 1.6 mm V0 V0 V0 V0 V0 V0 UL-94 0.8 mm V2 V2 V0 V0 V0 V0

TABLE-US-00006 TABLE 6 Example and Comparative Example flame retardant formulations on PA base C.44 E.45 C.46 E.47 PA6 51% 51% 48% 48% GF 30% 30% 30% 30% IP-A 11% — 11% — E.18 — 11% — 11% MC  8%  8%  8%  8% EVOH  3%  3% UL-94 3.2 mm V0 V0 V0 V0 UL-94 1.6 mm V0 V0 V0 V0 UL-94 0.8 mm V2 V2 V0 V0

TABLE-US-00007 TABLE 7 Example and Comparative Example of flame retardant formulations on HIPS base C.48 E.49 C.50 E.51 C.52 E.53 HIPS 64.7% 64.7% 78.8% 78.8% 75.8% 75.8% IP-A 24.5% —   5% —   6% — E.18 — 24.5% —   5% —   6% PX200 10.5% 10.5% 8010 — — .sup. 15% .sup. 15% — — FR245 — — — — .sup. 18% .sup. 18% PTFE  0.3%  0.3%  0.2%  0.2%  0.2%  0.2% UL-94 1.6 mm V0 V0 V0 V0 V0 V0

TABLE-US-00008 TABLE 8 Example and Comparative Example of flame retardant formulations on PC base C.54 E.55 C.56 E.57 PC 92% 92% 94.7% 94.7% IP-C  8%   5% — E.19 —  8% —   5% PTFE  0.3%  0.3% UL-94 1.6 mm V0 V0 V0 V0