Bromine-containing polymers useful as flame retardants

Abstract

The invention relates to a process for preparing bromine-containing polymer, comprising a Friedel-Crafts alkylation reaction of tetrabromoxylylene dihalide, or tetrabromoxylylene dihalide in combination with pentabromobenzyl halide, with a reactant having one or more six-membered aromatic rings, wherein the reaction takes place in a solvent in the presence of a Friedel-Crafts catalyst, and isolating from the reaction mixture the bromine-containing polymer. The so-formed polymers and their use as flame retardants form additional aspects of the invention.

Claims

1. A polymer having CH.sub.2C.sub.6Br.sub.4CH.sub.2 and A units arranged alternately along the polymer backbone chain:
CH.sub.2C.sub.6Br.sub.4CH.sub.2-A-CH.sub.2C.sub.6Br.sub.4CH.sub.2-A-CH.sub.2C.sub.6Br.sub.4CH.sub.2-A-CH.sub.2C.sub.6Br.sub.4CH.sub.2-A wherein A comprises one or more six-membered aromatic rings, the polymer further comprising CH.sub.2C.sub.6Br.sub.5 side groups attached to at least a portion of the six-membered aromatic rings of the backbone chain, wherein at least one carbon atom of said six-membered aromatic ring(s) is bonded to the aliphatic carbon of said CH.sub.2C.sub.6Br.sub.5 group.

2. A polymer according to claim 1, composed of chains represented by Formula P: ##STR00018## wherein n is the number of repeat units; Ar indicates a structure comprising one or more six-membered aromatic ring(s), wherein at least one carbon atom of said six membered aromatic ring(s) is bonded to an aliphatic carbon of the CH.sub.2C.sub.6Br.sub.4CH.sub.2 group; where x, which indicates the number of CH.sub.2C.sub.6Br.sub.4CH.sub.2 moieties in the unit, is equal to or greater than 1; and y, which indicates the number of CH.sub.2C.sub.6Br.sub.5 pendent groups in the repeat unit, is 1, 2, 3, or 4.

3. A polymer according to claim 1, having chains with repeat units represented by Formula (I): ##STR00019## wherein R is a linear or branched aliphatic chain; k is an integer from 0 to 3; a.sub.1 and a.sub.2 are independently an integer from 1 to 3; b.sub.1 and b.sub.2 are independently an integer from 1 to 3; m is 0 or 1; a.sub.1+b.sub.13 and a.sub.2+b.sub.23, Z is selected from the group consisting of null, O, S and a linear or branched alkylene.

4. A polymer according to claim 3, composed of repeat units of Formula I, where m=0, R is CH.sub.3 and k is 1.

5. A polymer according to claim 4, composed of repeat units of Formula I, where a.sub.1=b.sub.1=1, said polymer being represented by Formula III: ##STR00020## where n is the number of repeat units.

6. A polymer according to claim 3, composed of repeat units of Formula I, where m=1 and k=0.

7. A polymer according to claim 6, composed of repeat units of Formula IV: ##STR00021## wherein Z is selected from the group consisting of O, CH.sub.2, and CH.sub.2CH.sub.2, with a1 and a2 being independently either 1, 2 or 3 and with b1 and b2 being independently 0, 1 or 2, having bromine content of not less than 60% by weight.

8. A polymer according to claim 7, composed of repeat units of Formula IV, where z is CH.sub.2CH.sub.2.

9. A polymer according to claim 8, composed of repeat units of Formula IV where b1=b2=2, said polymer being represented by Formula V: ##STR00022## wherein n is the number of repeat units.

10. A flame-retarded composition, comprising a flammable material and the bromine-containing polymer according to claim 9.

Description

EXAMPLES

(1) Methods

(2) TGA Analysis:

(3) The TGA analysis was performed by a Mettler-toledo instrument model 850. 10 mg sample were heated in aluminum oxide crucible from 35 to about 700 C. with heating rate of 10 C./min in nitrogen atmosphere.

(4) Bromine Content:

(5) Bromine content of the compounds is measured by the Parr Bomb method. The sample (0.08-0.12 g) is placed in a peroxide bomb vessel. Sucrose (0.5 g) is added and the full dipper of sodium peroxide is also added. The sample is subjected to oxidizing with sodium peroxide while a burner flame is applied to the bottom of the bomb; the bomb is heated up to about 200 C. and the burner is then turned off. The bomb is placed in cold water (2 liters). Gaseous products are absorbed by the alkaline mixture and are retained within the bomb, mostly in the form of sodium bromide. The content of the bomb is then combined with warm water. Hydrazine sulfate is added to destroy residual sodium peroxide. Nitric acid is added in portions, until the solution is completely neutralized and becomes acidic. The solution is cooled to room temperature and then subjected to titration with AgNO.sub.3 (0.1N) to determine bromine content.

Example 1

Reaction of Toluene with PBBBr and TBX-DB

(6) DCE (300 ml), PBBBr (84.8 g, 0.15 mol), TBX-DB (66.1 g, 0.114 mol), and toluene (13.8 g, 0.15 mol) were placed in a 500 ml reactor fitted with a mechanical stirrer, thermometer, condenser, HBr trap and N2 inlet. The mixture was heated to 60 C. AlCl.sub.3 (1.3 g, 0.01 mol) was added by portions and the vigorous formation of HBr started. The mixture was kept at 60 C. for 2-4 hours until the PBBBr and TBX-DB disappeared (detected by GC and HBr evolution). The reaction mixture was washed three times with water (3300 ml) and an aqueous solution of NaHCO.sub.3, taking 30 minutes for each washing. The reaction mixture was cooled to 50 C. and the solid was filtered off and dried in an oven at 150 C. under reduced pressure for 24 hours, giving 131.3 g, corresponding to an 98% yield. The content of bromine was about 70%.

(7) The TGA profile of the so-formed product is tabulated below:

(8) TABLE-US-00003 Temperature T1 = 360 C. T2 = 398 C. T3 = 415 C. % weight loss 2.0 5.0 10.0

Example 2

Reaction of Toluene with PBBBr and TBX-DB

(9) The procedure of Example 1 was repeated, but a solution of DCE (35 ml) and toluene was added dropwise over 1.5 h. The weight of the product was 132.5 g, corresponding to 99% yield. The content of bromine was about 69.0%.

Example 3

Reaction of Toluene with PBBBr and TBX-DB

(10) The procedure of Example 1 was repeated, using DBM (1.25 l) instead of DCE, PBBBr (424.1 g, 0.75 mol), TBX-DB (312.9 g, 0.54 mol), toluene (69.1 g, 0.75 mol), and AlCl.sub.3 (1.3 g, 0.01 mol). After washing, the suspension of the product was added dropwise to IPA (iso-propyl alcohol) (3.5 l), stirred at 20 C. for 30 min and the product was filtered off. The weight of the dried product was 642.0 g, corresponding to 97% yield. The content of bromine was about 72%.

Example 4

Reaction of Toluene with PBBBr and TBX-DB

(11) The procedure of Example 1 was repeated using DBM (250 ml) instead of DCE, PBBBr (84.8 g, 0.15 mol), TBX-DB (62.6 g, 0.108 mol), toluene (13.9 g, 0.15 mol), and AlCl.sub.3 (0.8 g, 0.006 mol). The PBBBr was added after the added TBX-DB had disappeared (about 1.5 h). After washing, the suspension of the product was added dropwise to IPA (700 ml), stirred at 20 C. for 30 min and the product was filtered off. The weight of the product was 127.8 g, corresponding to 96% yield. The content of bromine was about 71%.

Example 5

Reaction of Diphenylethane with PBBBr and TBX-DB

(12) The procedure of Example 1 was repeated, but using DBM (250 ml) instead of DCE, diphenylethane instead of toluene (9.1 g, 0.05 mol), PBBBr (113.1 g, 0.2 mol), TBX-DB (20.3 g, 0.035 mol), and AlCl.sub.3 (0.8 g, 0.006 mol). After washing, the suspension of the product was added dropwise to IPA (1000 ml), stirred at 20 C. for 30 min and the product was filtered off. The weight of the product was 114.8 g, corresponding to 94% yield. The content of bromine was about 75%. In view of the bromine content, the product is assigned with the following structure:

(13) ##STR00015##
The TGA profile of the product is tabulated below:

(14) TABLE-US-00004 Temperature T1 = 343 C. T2 = 371 C. T3 = 391 C. % weight loss 2.0 5.0 10.0

Example 6

Reaction of Diphenylethane with TBX-DB

(15) The procedure of Example 1 was repeated, but using diphenylethane instead of toluene (10.9 g, 0.06 mol), TBX-DB (104.3 g, 0.18 mol), DCM (250 ml) and AlCl.sub.3 (1.1 g, 0.09 mol). The weight of the product was 89.6 g. The content of bromine was about 66%.

Example 7

Reaction of Diphenyloxide with PBBBr and TBX-DB

(16) The procedure of Example 5 was repeated, but using diphenyloxide instead of diphenylethane (8.5 g, 0.05 mol). The weight of the product was 115.1 g, corresponding to a 96% yield. The content of bromine was about 75%.

Example 8

Reaction of Diphenylmethane with PBBBr and TBX-DB

(17) The procedure of Example 5 was repeated, but using diphenyloxide instead of diphenylethane (8.5 g, 0.05 mol). The weight of the product was 115.1 g, corresponding to a 96% yield. The content of bromine was about 75%.

(18) In the studies reported in the following examples, the ability of bromine-containing polymers of the invention to reduce the flammability of different thermoplastic was evaluated. Test specimens were prepared and subjected to a flammability test according to the Underwriters-Laboratories standard UL 94, applying the vertical burn on specimens of 0.8, 1.6 mm or 3.2 mm thickness.

Examples 9 to 11

V-1 and V-0 Rated HIPS Formulations

(19) In this set of examples, the compound of Formula III (the product of Examples 1 and 3) was tested to evaluate its ability to reduce the flammability of HIPS.

(20) Ingredients Used to Prepare the Compositions

(21) The materials employed in the experimental work are set out in Table 1 (the abbreviation FR indicates flame retardant):

(22) TABLE-US-00005 TABLE 1 Product (manufacturer) description function Styron 1200 (Dow) High impact polystyrene plastic matrix Product of Examples 1,3 FR AO 0112 (Kafrit) Antimony trioxide masterbatch which contains 80% by FR-synergist weight Sb.sub.2O.sub.3 Hostaflon 2017 PTFE Anti-dripping (Dyneon) agent Irganox B-225 (Ciba) 50% tris(2,4-ditert-butylphenyl)phosphite and 50% Antioxidant & pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4- heat stabilizer hydroxyphenyl]propionate]
Preparation of HIPS Compositions and Test Specimens

(23) The ingredients were compounded in a twin-screw co-rotating extruder (Berstorff ZE25) with L/D=32. The polymer and the additives were weighed and mixed, and the resultant blend was fed directly to the extruder port. A set temperature profile of 80-180-190-200-200-200-210-220 C. was employed. The screw speed was 350 rpm, and the feeding rate was 15 kg per hour.

(24) The extrudates obtained were pelletized in pelletizer 750/3 (Accrapac Systems Limited). The resultant pellets were dried in a circulating air oven at 75 C. for four hours.

(25) The dried pellets were injection molded into test specimens using Allrounder 500-150 (Arburg). The conditions of the injection molding are set out in Table 2.

(26) TABLE-US-00006 TABLE 2 PARAMETER UNITS Set values T.sub.1 (Feeding zone) C. 200 T.sub.2 C. 205 T.sub.3 C. 210 T.sub.4 C. 215 T.sub.5 (nozzle) C. 220 Mold temperature C. 30 Injection pressure bar 1200 Holding pressure bar 600 Back pressure bar 50 Holding time sec 7 Cooling time sec 18 Filling volume (portion) ccm 38 Injection speed ccm/sec 35 Switch over point [ccm] 12

(27) The specimens produced were conditioned at 23 C. for one week and were then subjected to the flammability test. The compositions produced and the results of the tests are set out in Table 3.

(28) TABLE-US-00007 TABLE 4 Example 9 10 11 Composition (by weight %) HIPS 82.2 83.325 81.575 FR: Compound of Formula III 12.5 13.75 16.25 Sb.sub.2O.sub.3 (as M-0112; containing 80% Sb.sub.2O.sub.3) 5 2.625 1.875 PTFE 0.1 0.1 0.1 Irganox B 225 0.2 0.2 0.2 Bromine content, % calculated 9 10 11.7 Antimony trioxide, % calculated 4.0 2.1 1.5 Properties Flammability test: UL-94 vertical burning test at 1.6 mm thickness Maximal flaming time (sec) 1 8 9 Total Flaming time (sec) 10 24 46 glowing + second flaming time (sec) 50 6 0 Number of Specimens dripped 0 0 0 Number of cotton ignition 0 0 0 Rating V-1 V-0 V-0

(29) The results indicate that UL-94 V-0 rating in HIPS is attainable with the aid of the product of Examples 1 or 3, with modest bromine content and low antimony trioxide loading in the HIPS composition.

Examples 12 and 13

V-1 and V-0 Rated ABS Formulations

(30) In this set of examples, the compound of Formula V (the product of Example 5) was tested to evaluate its ability to reduce the flammability of ABS.

(31) Ingredients Used to Prepare the Compositions

(32) The materials employed in the experimental work are set out in Table 1 (the abbreviation FR indicates flame retardant):

(33) TABLE-US-00008 TABLE 4 Product (manufacturer) description function ABS Magnum 3404 Acrylonitrile-butadiene-styrene plastic matrix (Styron) copolymer Product of Example 5 FR AO 0112 (Kafrit) Antimony trioxide masterbatch which contains 80% by weight Sb.sub.2O.sub.3 FR-synergist Hostaflon 2017 PTFE Anti-dripping (Dyneon) agent Irganox B-225 (Ciba) 50% tris(2,4-ditert-butylphenyl)phosphite and 50% pentaerythritol Antioxidant & tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate] heat stabilizer
Preparation of ABS Compositions and Test Specimens

(34) The ingredients were compounded in a twin-screw co-rotating extruder (Berstorff ZE25) with L/D=32. The polymer and the additives were weighed and mixed, and the resultant blend was fed directly to the extruder port. A set temperature profile of 160-180-210-210-210-210-220-230 C. was employed. The screw speed was 350 rpm, and the feeding rate was 12 kg per hour.

(35) The extrudates obtained were pelletized in pelletizer 750/3 (Accrapac Systems Limited). The resultant pellets were dried in a circulating air oven at 80 C. for three hours.

(36) The dried pellets were injection molded into test specimens using Allrounder 500-150 (Arburg). The conditions of the injection molding are set out in Table 5.

(37) TABLE-US-00009 TABLE 5 PARAMETER UNITS Set values T.sub.1 (Feeding zone) C. 210 T.sub.2 C. 215 T.sub.3 C. 220 T.sub.4 C. 225 T.sub.5 (nozzle) C. 230 Mold temperature C. 40 Injection pressure bar 1200 Holding pressure bar 800 Back pressure bar 50 Holding time sec 7 Cooling time sec 18 Filling volume (portion) ccm 37.5 Injection speed ccm/sec 30 Switch over point [ccm] 12

(38) The specimens produced were conditioned at 23 C. for one week and were then subjected to the flammability test. The compositions produced and the results of the tests are set out in Table 6.

(39) TABLE-US-00010 TABLE 6 Example 12 13 Composition (% by weight) ABS 81.4 80.5 product of Example 5 13.3 17.3 Sb.sub.2O.sub.3 (as M-0112; containing 80% Sb.sub.2O.sub.3) 5.0 1.9 PTFE 0.1 0.1 Irganox B 225 0.2 0.2 Bromine content, % calculated 10.0 13.0 Antimony trioxide, % calculated 4.0 1.5 Properties Flammability test: UL-94 vertical burning test at 1.6 mm thickness Maximal flaming time (sec) 1 6 Total Flaming time (sec) 10 21 Maximal glow time + second flaming 30 2 Number of Specimens dripped 0 0 Number of cotton ignition 0 0 Number of Specimens burning up to the clamps 0 0 Rating V-0 V-0

(40) The results show that UL-94 V-0 rating in ABS is attainable with the aid of a combination consisting of the product of Example 5 and antimony trioxide. The loading of the bromine-containing flame retardant and the antimony trioxide is fairly reasonable, and the UL-94 V-0 rating is achieved across a wide range of bromine: Sb.sub.2O.sub.3 weight ratio.