chain scission fr mechanism of aliphatic bromine compounds in ps an pp - j. kaspersma

7/30/2019 Chain Scission FR Mechanism of Aliphatic Bromine Compounds in PS an PP - J. Kaspersma

1/18

Great Lakes Chemical CorporationTechnical Service EMEA

Chain Scission FR Mechanism

of aliphatic bromine compounds in PS and PP

Jelle H.Kaspersma

FR Technical ServiceHerentals, Belgium


2/18


3/18


Flame Poisoning Mechanismaromatic bromine, Sb2O3 synergist

gas phase mechanism, polymer unspecific

Br FR + Sb2O3 SbBr3 + H

HBr

High energy H

and OH

are generated in the partial oxidation cycle of hydrocarbons:

start: RH R

+ H

growth: R

+ O2 ROO

+ RH ROOH + R

branching: ROOH RO

+ OH

High energy radicals are removed by HBr and SbBr3 , the flame is extinguished:

HBr + H

H2 + Br

HBr + OH

H2O + Br


4/18


Chain Scission Mechanism

aliphatic bromine, in polymer meltpolymers with tertiary carbon

CH C

H

H

CHH

HCHH

H

CH C

H

H

Br FR FR

+ Br

Br +.C

H

CHHHCHHH

CH C

H

HCH

.C

H

CHHHCHHH

CH C

H

HCH

+ .CHH

H

CH C

H

H

CHHH

C

HCH

.CHH

H

CH C

H

H.CHH

H

CHC

H

H

+ CHH

H

CHC

H

H

+

CHH

H

CHC

H

H

scission

termination

H abstraction

HBr +


5/18


Br FR additives

BrBr

BrBr

Br Br

CH2 CH

Br Br

CH2 O O

Br

Br

Br

Br

CH3

CH3

C CH2 CH

Br

CH2

Br

Mixed aliphatic/aromatic bromine FR compoundTetrabromo bisphenol A bis (2,3-dibromopropyl ether)

Commercial name PE-68 used in PP

Fully aliphatic bromine FR compound Hexabromo cyclo dodecane

Commercial name CD-75P used in PSCD-75Pstab contains 5% acid scavenger

O

Br Br

Br Br

Br

Br

BrBr

Br

Br

Aromatic bromine FR compoundDecabromo diphenyl oxide

Commercial name DE-83R used in HIPS and PP


6/18


FR test methods

UL94 V2: 2 times flame application for 10 seconds

Average burn time less than 25 seconds

Burning drips are allowed

Glow Wire: Application of hot wire at 960, 850 or 750oC

On most critical area of molded partContact for 30 seconds

Additional burn time less than 30 seconds (60 in total)

Burning drips are not allowed


7/18


Results of CD-75Pstab

in HIPS

HIPS with 6.5% rubber

FR loading for Glow Wire 960oC vs. UL94 V2

Glow Wire 960oC UL 94 V2

thickness CD-75Pstab contentAv.burn time

thickness CD-75stab contentAv.burn time

1 mm 2.1 % 10 20 sec 0.8 mm 1.6 % 2 sec

1.5 mm 4.2 % 10 20 sec 1.6 mm 1.6 % 5 sec

3 mm 2.1 % 10 20 sec 3.2 mm 1.6 % 2 sec


8/18


Result of CD-75Pstab in HIPS

Effect of rubber and mineral oil

CD-75Pstab in 1.5 mm Glow Wire plaque at 960oC

HIPS with 6.5 % rubber HIPS MFI 7 with 1.8 % mineral oil

Mineral oil

CD-75Pstab

Result

Av.burn time

Rubber

CD-75Pstab

Result

Av.burn time

1.8 % 4.2 % Pass 39 sec 6.5 % 4.2 % Pass 10 20 sec

0.9 % 4.2 % Pass 5 sec 9.5 % 6.0 % Pass 10 20 sec


9/18


Results of CD-75Pstab + Dicumene in HIPS


H

C

C

C

H HH

HH

C

C

C

H

H

HH

HH

C

C

C

H

H

HH

HH

2.

Glow Wire 960oC on 1.5 mm UL94 V2 on 1.6 mm

CD-75Pstab Dicumene

ResultAv. burn time

CD-75PstabDicumene

ResultAv. burn time

4.2 % - Pass 16 sec 1.6 % - Pass 3 sec

3.0 % 0.3 % Pass 12 sec 1.6 % 1.6 % Pass 1 sec

- 4.0 % Fail > 60 sec - 1.6 % Fail > 30 sec


10/18


Results of CD-75Pstab + Sb2O3 in HIPS


Glow Wire 960oC on 1.5 mm UL94 V2 on 1.6 mm

CD-75Pstab Sb2O3 Result

Av.burn time

CD-75Pstab Sb2O3 Result

Av.burn time

4.2 % - Pass 16 sec 1.6 % - Pass 5 sec

4.2 % 1.4 % Pass 14 sec 1.0 % 0.33 % Fail > 30 sec

3.5 % 1.2 % Pass 12 sec 2.0 % 0.67 % Fail > 30 sec

G L k Ch i l C i


11/18


Conclusions for CD-75Pstab in HIPS

Additive effects indicate:

Chain Scission is the main mechanism for V2:

- Sb2O3 removes Br radicals from the melt, fails V2

- Dicumene enhances Chain Scission, a real synergist

A mixed Chain Scission/Flame Poisoning Mechanism for Glow Wire:

- Both Sb2

O3

and Dicumene are synergists

- Strong effect of rubber on FR loading by counteracting flow

UL V2 easier to pass than Glow Wire in HIPS

- No Sb2O3 for Flame Poisoning, needed more for Glow Wire

G t L k Ch i l C ti


12/18


Results of PE-68 + Sb2O3 in PP

PPhomopolymer MFI 11

FR/Sb2O3 1.0 2.0 3.0 6.0PE-68 % 1.5 % 1.5 % 1.5 % 1.5 %

Sb2O3 % 1.5 % 0.75 % 0.5 % 0.25 %

UL94 V2 Result / Av. burn time

0.8 mmPass

4 sec

Pass

4 sec

Pass

2 sec

No result

1.6 mm

Pass

5 sec

Pass

3 sec

Pass

3 sec

Fail

(1/10 fail)

3.2 mmFail(4/10 fail)

Fail(1/10 fail)

Pass

2 sec

Fail(3/10 fail)

Great Lakes Chemical Corporation


13/18


Results of PE-68 in PP

PPhomopolymer MFI 11Glow Wire 960oC vs UL94 V2 loading

Glow Wire 960oC UL 94 V2gage PE-68

Sb2O3

ResultAv.burn time

gage PE-68Sb2O3

ResultAv.burn time

1.0 mm

1.0 %

0.33 %

Pass

21 sec0.8 mm

1.5 %

0.5 %

Pass

2 sec

1.5 mm1.0 %

0.33 %

Pass

25 sec

1.6 mm1.5 %

0.5 %

Pass

3 sec

3.0 mm1.0 %

0.33 %

Pass

31 sec3.2 mm

1.5 %

0.5 %

Pass

6 sec



14/18


Conclusions for PE-68 in PP

Additive effects indicate:

A mixed Chain Scission/FlamePoisoning Mechanism for V2 and Glow Wire

- Aliphatic Br sustains the Chain Scission mechanism

- Aromatic Br sustains Flame Poisoning with Sb2O3 synergist

- Lower FR loading for Glow Wire vs V2:

Flame Poisoning more important for Glow Wire than for V2



15/18


Comparison of Br FR load levels for V2 and V0

Aliphatic or mixed Aliphatic/Aromatic vs fully Aromatic Br

HIPS6.5% rubber CD-75Pstab Sb2O3 DE-83R Sb2O3

AliphaticBr

AromaticBr

UL94 V21.6 mm

1.6 % - 6.0 % 2.0 % 1.1 % 5.0 %

UL94 V01.6 mm

8.0 % 3.0 % 11.5 % 3.5 % 5.7 % 9.5 %

PP

homopolMFI 11

PE-68 Sb2O3 DE-83R Sb2O3

Mixed

Br

Aromatic

Br

UL94 V21.6 mm

1.5 % 0.5 % unknown 1.0 % -

UL94 V01.6 mm

10.0 % 3.0 % 23.0 % 10.0 % 6.8 % 19.1 %



16/18


Conclusions on Chain Scission in V2/V0 in PS and PP

Comparison of Aliphatic and Aromatic Br in V2 and V0 in HIPS:

- For V2 Aliphatic Br is 450% more effective than Aromatic Br

- For V0 Aliphatic Br is 60% more effective than Aromatic Br

Comparison of mixed Aliphatic/Aromatic and Aromatic Br in V0 in PP:

- For V0 mixed Aliphatic/Aromatic Br is 280% more effective than Aromatic Br

The Chain Scission Mechanism is more effective



17/18


Results of Mixed Br FR vs Non Hal FR in PPV2 and V0 in 1.6 mm

CH2HO CCH2

CH2

CH2

O

OO

P ONH-1197, Pentaerithritol phosphate

NH-1511, blend of NH-1197 withphosphate synergist

NH-1197

PE-68 vs Non Hal NH-1511 in PP homopolymer MFI =11

FR additive FR loading for UL94 V0 in 1.6 mm

FR loading forUL94 V2 in 1.6 mm

PE-68 + Sb2O3 10% PE-68 + 3.3% Sb2O3 1.5% PE-68 + 0.5% Sb2O3

NH-1511 28 % 23 %



18/18

pTechnical Service EMEA

Final Conclusions

Relative importance of Chain Scission vs. Flame Poisoning:

- for V2 Chain Scission is most important

- for Glow WireChain Scission and Flame Poisoning are equally important

- for V0 Flame Poisoning is most important, but Chain Scission contributes a lot

Aliphatic Br FR`s are very effective for European FR ratings in PS and PP

Non-Halogen FR`s can be effective for V0 by a Charring Mechanism

Non-Halogen FR`s are not effective for V2/Glow Wire: no Chain Scission

chain scission fr mechanism of aliphatic bromine compounds in ps an pp - j. kaspersma

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