FLAME RETARDANT POLYOLEFIN ARTICLES

Abstract

The present invention relates to a flame-retardant article comprising a polyolefin substrate having additives incorporated therein, the additives comprising: a specific phosphonate ester of formula (1), a synergist comprising an N-alkoxy hindered amine, and a melamine cyanurate.

The present invention also relates to corresponding flame retardant compositions, and the use of these for improving the flame retardency of polyolefins.

Claims

1.-19. (canceled)

20. A mixing process comprising introducing an additive to a polyolefin during processing in an extruder, where the additive comprise a phosphonate ester of formula ##STR00056## wherein R.sub.1 and R.sub.2 are independently selected from a group consisting of alkyl, optionally substituted alkyl, benzyl, optionally substituted benzyl, phenyl, optionally substituted phenyl, naphthyl, and optionally substituted naphthyl, an N-alkoxy hindered amine, where the N-alkoxy hindered amine is of the formula (7) ##STR00057## wherein E.sub.1 is C.sub.1-C.sub.18alkoxy or hydroxyl-substituted C.sub.1-C.sub.18alkoxy, and a melamine cyanurate.

21. The mixing process according to claim 20 where the weight:weight ratio of the organic phosphorus stabilizer to the hindered phenolic antioxidant is from about 9:1 to about 1:9.

22. The mixing process according to claim 20 where the extruder is a single-screw extruder, contrarotating and corotating twin-screw extruder, planetary-gear extruder, ring extruder.

23. The mixing process according to claim 20 where the extruder is provided with at least one gas removal compartment to which a vacuum can be applied.

24. The mixing process according to claim 20 where the extruder has a screw length of 1-60 screw diameters, preferably 35-48 screw diameters.

25. The mixing process according to claim 20 where the extruder has a rotational speed of the screw from 10-600 rotations per minute (rpm), very particularly preferably 25-300 rpm.

26. The mixing process according to claim 20 where the polyolefin comprises a polymer selected from a group consisting of polypropylene, polyethylene, and copolymers or mixtures thereof.

27. The mixing process according to claim 20 where R.sub.1 and R.sub.2 are methyl or benzyl, especially methyl.

28. A masterbatch comprising a phosphonate ester of formula (1) in an amount of 10% to 80%, especially 20% to 70% and more preferably 30% to 60% by weight, a melamine cyanurate in an amount of 10% to 80%, especially 20% to 70% and more preferably 30% to 60% by weight, and an N-alkoxy hindered amine in an amount of 1% to 50%, especially 1% to 30% and more preferably 2% to 20% by weight, and where the N-alkoxy hindered amine is of the formula (7) ##STR00058## wherein E.sub.1 is C.sub.1-C.sub.18alkoxy or hydroxyl-substituted C.sub.1-C.sub.18alkoxy.

29. The masterbatch according to claim 28 comprising the phosphonate ester of formula (1) in an amount of 20% to 70% and more preferably 30% to 60% by weight, the melamine cyanurate in an amount of 20% to 70% and more preferably 30% to 60% by weight, and the N-alkoxy hindered amine in an amount of 1% to 30% and more preferably 2% to 20% by weight.

30. The masterbatch according to claim 28 where the weight:weight ratio of the organic phosphorus stabilizer to the hindered phenolic antioxidant is from about 9:1 to about 1:9, as well as with ratios in between, for instance about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, or about 1:8 with ratios in between the aforementioned ratios.

31. The masterbatch according to claim 28 comprising 1% to 50%, especially 1% to 30% and more preferably 1% to 20% by weight of a polyolefin.

32. The masterbatch according to claim 28 where the polyolefin comprises a polymer selected from a group consisting of polypropylene, polyethylene, and copolymers or mixtures thereof.

33. The masterbatch according to claim 28 where R.sub.1 and R.sub.2 are methyl or benzyl, especially methyl.

Description

EXAMPLE 1: FLAME RETARDANCY PERFORMANCE OF POLYETHYLENE FILMS CONTAINING DIFFERENT COMBINATIONS OF FLAME RETARDANTS

a) Polymer Component and Light Stabilizer

[0200] Polymer component (LLDPE): LLDPE, DOWLEX SC 2108G, manufacturer Dow [0201] Light stabilizer (LS): Chimassorb 2020, manufacturer BASF SE

b) Flame Retardant Components

[0202] FR-1: 1-(2-hydroxy-2-methylpropoxy)-4-octadecanoyloxy-2,2,6,6-tetramethylpiperidine [0203] FR-2: Pentaerythritol-di-methyl diphosphonate (available as AFLAMMIT PCO 900 from THOR GROUP LIMITED) [0204] FR-3: Melamine cyanurate (available as Melapur MC from BASF SE)

c) LLDPE Film Manufacture

[0205] Unless stated otherwise, LLDPE, LS and the corresponding flame retardant components FR-1, FR-2 and FR-3 are dry blended in the amounts as indicated and then melt compounded into pellets on a co-rotating twin-screw extruder Berstorff 46D (lab size twin screw extruder, 25 mm screw diameter) at a maximum temperature T.sub.max of 230 C.

[0206] The pelletized fully formulated resin is then casted at a maximum temperature T.sub.max of 220 C. into 250 m films using a cast film equipment Collin CR-136/350 coupled with an extruder Collin E 30 M.

d) Performance of Formulation as Flame Retardant

[0207] The produced films are evaluated according to the standard DIN4102-Part 1 (May 1998). DIN4102-Part 1: The specimen is positioned vertically and the ignition flame is applied at the lower edge of the specimen (edge ignition test).

[0208] Classification is based on the time for flames to spread 150 mm of the specimen.

[0209] If the flame does not reach the 150 mm reference mark within 20 s, the tested film passes the test and is classified B2.

[0210] If the flame reaches the 150 mm reference mark within 20 s, the tested film is non classified (n.c.)

[0211] Concentrations of additives and performance of film specimen are given in Tables 1 and 2

TABLE-US-00001 TABLE 1 Concentrations of added additives in the LLDPE cast film Comparative Compositions (compositions not according to the present invention): Ref. 1, 2, 3, 4, 5 and 6 Compositions according to the present invention: Inv. 1 and Inv. 2 Film No. Additive* Ref. 1 No FR Ref. 2 2% FR-1 Ref. 3 5% FR-2 Ref. 4 5% FR-3 Ref. 5 0.4% FR-1 + 4.6% FR-3 Ref. 6 2.5% FR-2 + 2.5% FR-3 Inv. 1 0.4% FR-1 + 1.8% FR-2 + 2% FR-3 Inv. 2 0.4% FR-1 + 4.6% FR-2 *Stabilization of all films with 0.2% Chimassorb 2020

TABLE-US-00002 TABLE 2 Flaming test on 250 m LLDPE cast films according to modified DIN 4102-Part 1 (edge ignition) Ref. 1 Ref. 2 Ref. 3 Ref. 4 Ref. 5 Ref. 6 Inv. 1 Inv. 2 LLDPE 100% 98% 95% 95% 95% 95% 95.8% 95% FR-1 2% 0.4% 0.4% 0.4% FR-2 5% 2.5% 1.8% 4.6% FR-3 5% 4.6% 2.5% 2% DIN4102-B2 rating with fail fail pass fail fail fail pass pass 250 m films.sup.a) Burning time [sec].sup.b) 43 21 11 33 30 16 7 6 Damaged length [mm].sup.c) 160 99 70 190 190 93 53 46 Burning drips paper ignition.sup.d) yes yes no yes yes yes no no .sup.a)Rated pass if flaming does not reach the 150 mm gauge mark within 20 seconds after flame application according to the DIN 4102-Part 1 test norm. .sup.b)Burning time, in second, is the duration of the flaming after flame application up to the extinction of flame. .sup.c)Damaged lenght, in mm, is the vertical part of the film being burned after the extinction of flame. .sup.d)Rated no if molten and burning drips that have fallen on the filter paper does not ignite the paper placed underneath the test specimen according to the DIN 4102-Part 1 test norm. no is the best rating. Inv. 1 and Inv. 2 increase significantly the FR performance of the composition in comparison to Comparative Compositions Ref. 1, 2, 3, 4, 5 and 6. The burning time and also the damaged length are considerably lower for Inv. 1 and Inv. 2, both pass the test according to DIN 4102-Part 1, and no burning drips ignite a paper placed underneath the test specimen.

EXAMPLE 2: FLAME RETARDANCY PERFORMANCE OF POLYETHYLENE FILMS CONTAINING DIFFERENT COMBINATIONS OF FLAME RETARDANTS

a) Polymer Component and Light Stabilizer

[0212] Polymer component (LLDPE): LLDPE, DOWLEX SC 2108G, manufacturer Dow [0213] Light stabilizer (LS): Chimassorb 2020, manufacturer BASF SE

b) Flame Retardant Components

[0214] FR-2: Pentaerythritol-di-methyl diphosphonate (available as AFLAMMIT PCO 900 from THOR GROUP LIMITED) [0215] FR-3: Melamine cyanurate (available as Melapur MC from BASF SE) [0216] FR-4: Compound of formula (5) (available as Flamestab NOR 116 FF from BASF SE) [0217] FR-5: Compound of formula (3) (available as Tinuvin NOR 371 from BASF SE) [0218] FR-6: Compound of formula (4)

c) LLDPE Film Manufacture

[0219] Unless stated otherwise, LLDPE, LS and flame retardant components FR-2, FR-3, FR-4, FR-5 and FR-6 are dry blended in the amounts as indicated and then melt compounded into pellets on a co-rotating twin-screw extruder Berstorff 46D (lab size twin screw extruder, 25 mm screw diameter) at a maximum temperature T.sub.max of 230 C.

[0220] The pelletized fully formulated resin is then casted at a maximum temperature T.sub.max of 220 C. into 250 m films using a cast film equipment Collin CR-136/350 coupled with an extruder Collin E 30 M.

d) Performance of Formulation as Flame Retardant

[0221] The produced films are evaluated according to the standard DIN4102-Part 1 (May 1998). DIN4102-Part 1: The specimen is positioned vertically and the ignition flame is applied at the lower edge of the specimen (edge ignition test).

[0222] Classification is based on the time for flames to spread 150 mm of the specimen.

[0223] If the flame does not reach the 150 mm reference mark within 20 s, the tested film passes the test and is classified B2.

[0224] If the flame reaches the 150 mm reference mark within 20 s, the tested film is non classified (n.c.)

[0225] Concentrations of additives and performance of film specimen are given in Tables 3 and 4

TABLE-US-00003 TABLE 3 Concentrations of added additives in the LLDPE cast film Comparative Composition (composition not according to the present invention): Ref. 1 Inventive Composition: Inv. 3, Inv. 4 and Inv. 5 Film No. Additive* Ref. 1 No FR Inv. 3 0.4% FR-4 + 2% FR-2 + 2% FR-3 Inv. 4 0.4% FR-5 + 2% FR-2 + 2% FR-3 Inv. 5 0.4% FR-6 + 2% FR-2 + 2% FR-3 *Stabilization of all films with 0.2% Chimassorb 2020

TABLE-US-00004 TABLE 4 Flaming test on 250 m LLDPE cast films according to modified DIN 4102-Part 1 (edge ignition) Ref. 1 Inv. 3 Inv. 4 Inv. 5 LLDPE 100% 95.6% 95.6% 95.6% FR-2 2% 2% 2% FR-3 2% 2% 2% FR-4 0.4% FR-5 0.4% FR-6 0.4% DIN4102-B2 rating with fail pass pass pass 250 m films.sup.a) Burning time [sec].sup.b) 43 16 8 6 Damaged length [mm].sup.c) 160 64 57 31 Burning drips paper yes no no no ignition.sup.d) .sup.a)Rated pass if flaming does not reach the 150 mm gauge mark within 20 seconds after flame application according to the DIN 4102-Part 1 test norm. .sup.b)Burning time, in second, is the duration of the flaming after flame application up to the extinction of flame. .sup.c)Damaged lenght, in mm, is the vertical part of the film being burned after the extinction of flame. .sup.d)Rated no if molten and burning drips that have fallen on the filter paper does not ignite the paper placed underneath the test specimen according to the DIN 4102-Part 1 test norm. no is the best rating.

[0226] Compositions Inv. 3, 4 and 5, which are combinations of N-alkoxy hindered amines (FR-4 or FR-5 or FR-6) with pentaerythritol-di-methyl diphosphonate (FR-2) and melamine cyanurate (FR-3), pass DIN 4102-Part 1 test, and are effective in reducing burning time and damaged length.