NOR-HALS compounds as flame retardants

Abstract

The present invention relates to the use of NOR-HALS compounds in flame retardant polymer compositions. These compositions are especially useful for the manufacture of flame retardant compositions based on thermoplastic polymers, especially polyolefin homo- and copolymers, polycondensates, such as polyamines or polyesters and duroplastic polymers, such as polyepoxides.

Claims

1. A composition, which comprises a) an NOR-HALS compound of the formula ##STR00014## wherein R.sub.1 and R.sub.2 represent n-undecyl; b) at least one flame retardant compound selected from the group consisting of tris(tribroromonepentvl)phosphate, resorcinol-bis-diphenylphosphate, pentaerythritol-di-methyl phosphonate, and ammonium polyphosphate; and c) a polymer substrate.

2. The composition according to claim 1, wherein component b) is at least one flame retardant compound selected from the group consisting of tris(tribromoneopentyl)phosphate, resorcinol-bis-diphenylphosphate, and ammonium polyphosphate.

3. The composition according to claim 1, further comprising as optional components additional flame retardants and additives selected from the group consisting of tetraalkylpiperidine additives, polymer stabilizers, fillers, reinforcing agents and anti-dripping agents that reduce the melt flow of thermoplastic polymers and reduce the formation of drops at higher temperatures.

4. The composition according to claim 3, which comprises an additional flame retardant which is a nitrogen containing compound selected from the group consisting of melamine polyphosphate, ammonium polyphosphate, melamine ammonium phosphate, melamine ammonium polyphosphate, melamine ammoninm pyrophosphate, a condensation product of melamine with phosphoric acid and other reaction products of melamine with phosphoric acid and mixtures thereof.

5. A process for inducing the flame retardancy in polymers, which comprises adding to a polymer substrate a combination of a) an NOR-HALS compound of the formula ##STR00015## wherein R.sub.1 and R.sub.2 represent n-undecyl; with b) at least one flame retardant compound selected from the group consisting of tris(tribromoneopentyl)phosphate, resorcinol-bis-diphenylphosphate, pentaerythritol-di-methyl phosphonate, and ammonium polyphosphate.

Description

(1) The following Examples illustrate the invention:

(2) A) Methods

(3) The following standard test methods are used to evaluate the performance of FR-1 as flame retardant:

(4) DIN 4102—Part 1

(5) The specimen is positioned vertically and the ignition flame is applied at the lower edge of the specimen (edge ignition test).

(6) Classification is based on the time for flames to spread 150 mm of the specimen.

(7) If the flame does not reach the 150 mm reference mark within 20 seconds, the tested film passes the test and is classified B2.

(8) UL 94-VTM and UL 94-V

(9) A flame is applied twice to the lower end of the test specimen positioned vertically.

(10) UL 94-VTM is a well-known test for classifying the flame retardancy of very thin material in 3 classes VTM-0, VTM-1 and VTM-2. The best rating is VTM-0.

(11) UL 94 test for Flammability of Plastic Materials for Parts in Devices and Appliances, 5th edition, Oct. 29, 1996. Ratings according to the UL 94 V test are compiled in the following table (time periods are indicated for one specimen):

(12) TABLE-US-00001 TABLE Rating After flame time [sec] Burning drips Burn to clamp V-0 <10 No No V-1 <30 No No V-2 <30 Yes No n.c. <30 Yes n.c. >30 No n.c.: not classified
FR-1

(13) ##STR00013##
B) Application Examples

Example 1

(14) Flame Retardancy of Fiber Grade Polypropylene (MFI 25) Containing 1% of FR-1

(15) PP Film Manufacture:

(16) Fiber grade polypropylene (Moplen® HP 552 (Basell)) is dry blended with 1% of FR-1 and melt compounded into pellets on a co-rotating twin-screw extruder type Berstorff 32D (lab size twin screw extruder, 25 mm screw diameter, 9 heating zones) at a temperature T.sub.max of 230° C.

(17) The pelletized fully formulated resin is cast at a maximum temperature T.sub.max of 200° C. into 250 μm films using a cast film equipment Collin CR-136/350 coupled with an extruder Collin E 30 M.

(18) Produced films and concentration of additive are listed in Table 1:

(19) TABLE-US-00002 TABLE 1 Concentration of added additive in the PP film Film No. Additive Film 1 No addition Film 2 1% FR-1

(20) Performance of FR-1 as Flame Retardant:

(21) TABLE-US-00003 TABLE 2 Flame test on 250 μm PP cast films according to modified DIN 4102-Part 1 (edge ignition) Burning Damaged Burning time length drips paper DIN 4102-B2 Film No. [sec] [mm] ignition .sup.f) Rating Film 1 33 190 yes not classified Film 2 8 62 no B2 .sup.f) Rated “yes”, if the burning drips ignite the paper placed underneath the test specimen according to the DIN 4102-Part 1 test norm.

(22) The burning time of Film 2 containing 1% FR-1 decreases significantly in comparison to Film 1. Film 2 is classified as B2. FR-1 contributes to lower the burning time and the damaged length and, therefore, increases flame retardancy of polypropylene.

(23) TABLE-US-00004 TABLE 3 Flame test on 250 μm PP cast films according to UL94-VTM Average flaming Specimen burnt UL94-VTM Film No. time .sup.a) [sec] to holding clamp Rating Film 1 31 Yes not classified Film 2 13 No VTM-2 .sup.a) Average flaming time per specimen and after maximum 2 ignitions

(24) The efficacy of FR-1 as a flame retardant is demonstrated by a lower average flaming time, with no specimen burnt to the clamp and VTM-2 classification.

Example 2

(25) Flame Retardancy of Cast Film Grade Polypropylene (MFI 8) Containing 1% of FR-1

(26) PP Film Manufacture

(27) Fiber grade polypropylene (RD204CF (Borealis)) is dry blended with 1% of FR-1 and melt compounded into pellets on a co-rotating twin-screw extruder type Berstorff 46D (lab size twin screw extruder, 25 mm screw diameter at a temperature T.sub.max of 250° C.

(28) The pelletized fully formulated resin is cast at a maximum temperature T.sub.max of 230° C. into 250 μm films using a cast film equipment Collin CR-136/350 coupled with an extruder Collin E 30 M.

(29) Produced films and concentration of additive are listed in Table 4.

(30) TABLE-US-00005 TABLE 4 Concentration of added additive in the PP film Film No. Additive Film 1 No addition Film 2 1% FR-1

(31) Performance of FR-1 as Flame Retardant:

(32) TABLE-US-00006 TABLE 5 Flame test on 250 μm PP cast films according to modified DIN 4102-Part 1 (edge ignition) Burning Damaged Burning time length drips paper DIN 4102-B2 Film No. [sec] [mm] ignition .sup.f) Rating Film 1 30 190 yes not classified Film 2 10 77 no B2 .sup.f) Rated “yes”, if the burning drips ignite the paper placed underneath the test specimen according to the DIN 4102-Part 1 test norm.

(33) The burning time of Film 2 containing 1% FR-1 decreases significantly in comparison with Film 1. Film 2 is classified B2. FR-1 contributes to lower the burning time and the damaged length and, therefore, increases the flame retardancy of polypropylene.

(34) TABLE-US-00007 TABLE 6 Flame test on 250 μm PP cast films according to UL94-VTM Average flaming Specimen burnt UL94-VTM Film No. time .sup.a) [sec] to holding clamp Rating Film 1 27 Yes not classified Film 2 7 No VTM-2 .sup.a) Average flaming time per specimen and after maximum of 2 ignitions

(35) The efficacy of FR-1 as a flame retardant is demonstrated by a lower average flaming time, with no specimen burnt to the clamp and VTM-2 classification.

Example 3

(36) Flame Retardancy of TPO (Thermoplastic Polyolefin) Membrane Containing 0.8% of FR-1

(37) TPO 1 mm Film Manufacture:

(38) Roofing membrane grade thermoplastic polyolefin (Hifax® CA 10 A Natural (Lyondell Basell Polymers)) is blended on two roll-mill equipment at 160° C. with 2% titanium dioxide pigment, 0.1% calcium stearate and FR-1 and melt compressed at the temperature of 170° C. into 1 mm plaques by using a hot press. Produced plaques and concentration of additives are listed in Table 7.

(39) TABLE-US-00008 TABLE 7 Concentration of added additive in the TPO Plaques Film No. Additive Plaque 1 No FR-1 Plaque 2 0.8% FR-1

(40) The test method according to DIN 4102—Part 1 is used to evaluate the performance of FR-1 as flame retardant:

(41) TABLE-US-00009 TABLE 8 Flame test on TPO plaques of 1 mm thickness according to modified DIN 4102-Part 1 (edge ignition) Burning Damaged Burning time length drips paper DIN 4102-B2 Film No. [sec] [mm] ignition f) Rating Plaque 1 75 >150 yes not classified Plaque 2 23 50 yes B2 f) Rated “yes”, if the burning drips ignite the paper placed underneath the test specimen according to the DIN 4102-Part 1 test norm.

(42) The burning time as well as the damaged length of Plaque 2 containing 0.8% FR-1 decreases significantly in comparison to Plaque 1. As a result, Plaque 2 is classified B2.

(43) FR-1 contributes to lower the burning time and the damaged length and therefore increases thermoplastic polyolefin flame retardancy.

Example 4

(44) Flame Retardancy of Injection Molded Grade Polypropylene (MFI 25) Containing FR-1

(45) Polymer Component: MOPLEN HP 552 R (Lyondell Basell (PP))

(46) Flame Retardant Components:

(47) ADK STAB LA-81 (ADEKA): bis(1-undecanyloxy-2,2,6,6-tetramethylpiperdin-4-yl)carbonate (FR-1) Aflammit® TL 1260 (THOR GROUP LIMITED): Pentaerythritol-di-methylphosphonate (FR-2) PP, FR-1 and FR-2 are premixed in the amounts indicated and melt compounded into pellets on a co-rotating twin-screw extruder Berstorff 32D (lab size twin screw extruder, 25 mm screw diameter) at a maximum temperature T.sub.max of 230° C.

(48) UL94-V test specimen of 1.6 mm thickness are prepared by injection molding (Engel EK 65).

(49) TABLE-US-00010 TABLE 9 Ref. 1 Ref. 2 Inv. 1 PP 100 84 84 FR-1 1 FR-2 16 15 UL 94 V at 1.6 mm n.c. V-2 V-0

(50) Ref. (Referential Compositions) 1, 2; Inv. (Inventive Composition) 1: Addition of FR-1 increases significantly the FR performance of the composition in comparison to Referential Compositions 1, 2. The efficacy of FR-1 as a flame retardant is demonstrated by V-0 classification.

Example 5

(51) Flame Retardancy of High Density Polyethylene (HDPE) Containing FR-1

(52) HDPE Film Manufacture:

(53) High density polyethylene (Hostalen® ACP 7740 F2 (Lyondell Basell)) is dry blended with FR-1 and melt compounded into pellets on a co-rotating twin-screw extruder type Collin 42D (lab size twin screw extruder, 25 mm screw diameter) at a maximum temperature T.sub.max of 210° C.

(54) The pelletized fully formulated resin is extruded and blown at a maximum temperature T.sub.max of 230° C. into film by using a blown film extrusion equipment Collin Type 180/400 coupled with an extruder Collin E 30 P.

(55) Produced films and concentration of additive are listed in Table 10.

(56) TABLE-US-00011 TABLE 10 Concentration of added additive in HDPE blown films Film No. Film Additive 1 100 μm No addition 2 200 μm No addition 3 100 μm 1.5% FR-1 4 200 μm 1.0% FR-1

(57) TABLE-US-00012 TABLE 11 Flame test on 200 μm HDPE blown films according to DIN 4102-Part 1 (edge ignition) Burning Damaged Burning time length drips paper DIN 4102-B2 Film No. [sec] [mm] ignition.sup.f) rating 2 31 >150 yes not classified 4 11 71 yes B2 .sup.f)Rated “yes”, if the burning drips ignite the paper placed underneath the test specimen according to the DIN 4102-Part 1 test norm.

(58) The burning time of Film 4 containing 1% FR-1 decreases significantly in comparison to Film 2. Film 4 is classified B2. FR-1 contributes to lower the burning time and the damaged length and therefore increases high density polyethylene flame retardancy.

(59) TABLE-US-00013 TABLE 12 Flame test on 100 μm HDPE blown films according to UL94-VTM Average flaming Specimen burnt UL94-VTM Film No. time.sup.a) [sec] to holding clamp rating 1 16.sup.b) Yes not classified 3 7 No VTM-2 .sup.a)Average flaming time per specimen and after maximum 2 ignitions .sup.b)Specimen completely burnt after the first ignition.

(60) The efficacy of FR-1 as a flame retardant is demonstrated by lower average flaming time, with no specimen burnt to the damp and VTM-2 classification.

Example 6

(61) Flame Retardancy of Linear Low Density Polyethylene (LLDPE) Containing FR-1

(62) LLDPE Film Manufacture:

(63) Linear low density polyethylene (1002YB (Exxon Mobile)) is dry blended with 1% FR-1 and melt compounded into pellets on a co-rotating twin-screw extruder type Collin 42D (lab size twin screw extruder, 25 mm screw diameter) at a maximum temperature T.sub.max of 210° C. The pelletized fully formulated resin is casted at a maximum temperature T.sub.max of 190° C. into 100 and 200 μm film by using a cast film equipment Collin CR-136/350 coupled with an extruder Collin E 30 M.

(64) Produced films and concentration of additive are listed in Table 13.

(65) TABLE-US-00014 TABLE 13 Concentration of added additive in the LLDPE cast film Film No. Film Additive 1 100 μm without addition 2 200 μm without addition 3 100 μm 1.0% FR-1 4 200 μm 1.0% FR-1

(66) TABLE-US-00015 TABLE 14 Flame test on 100 and 200 μm LLDPE cast films according to modified DIN 4102-Part 1 (edge ignition) Burning Damaged Burning time length drips paper DIN 4102-B2 Film No. [sec] [mm] ignition.sup.f) Rating Film 1 21 >150 yes not classified (100 μm) Film 2 3 62 no B2 (100 μm) Film 3 32 >150 yes not classified (200 μm) Film 4 6 54 yes B2 (200 μm) .sup.f)Rated “yes”, if the burning drips ignite the paper placed underneath the test specimen according to the DIN 4102-Part 1 test norm.

(67) The burning time of Film 2 and 4 containing 1.0% FR-1 decreases significantly in comparison to Film 1 and 3. Film 2 and 4 are classified B2. FR-1 contributes to lower the burning time and the damaged length and, therefore, increases the flame retardancy in low density polyethylene.

(68) TABLE-US-00016 TABLE 15 Flame test on 100 and 200 μm LLDPE cast films according to UL94-VTM Average flaming Specimen burnt UL94-VTM Film No. time.sup.a) [sec] to holding clamp Rating Film 1 14.sup.b) Yes not classified (100 μm) Film 2 4 No VTM-2 (100 μm) Film 3 23.sup.b) Yes not classified (200 μm) Film 4 15   No VTM-2 (200 μm) .sup.a)Average flaming time per specimen and after maximum 2 ignitions .sup.b)Specimen completely burnt after the first ignition.

(69) The efficacy of FR-1 as a flame retardant is demonstrated by lower average flaming time, with no specimen burnt to the clamp and VTM-2 classification.