Hindered Diazacycloalkanones as Ultraviolet Stabilizers and

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7 Hindered Diazacycloalkanones as Ultraviolet Stabilizers and Antioxidants J. T. LAI, P. N. SON, and E. JENNINGS The BFGoodrich Company, Brecksville, OH 44141

The properties of hindered diazacycloalkanones were evaluated as light stabilizers and antioxidants for polypropylene. A totally hindered piperazinone was found to be excellent light stabilizer with many other desirable properties as a polymer additive. Partially hindered decahydroquinoxalinone derivatives were found to be surprisingly good antioxidants. The relationship between structure parameters and activity was investigated. Since Hindered Amine Light Stabilizers (HALS) were first introduced about a decade ago, their commercial applications have proliferated to the stage where they may well dominate the polymer light stabilizers market in the near future. Among the many commercial and experimental HALS, only the BFGoodrich Company offers one that does not bear a 2,2,6,6-tetramethylpiperidine (1) structure. In this presentation, we would like to report our work on the chemistry and properties of our developmental HALS 1,1 -(1,2-ethanediyl) bis(3,3,5,5-tetramethyl-2-piperazinone) (2), and the interesting antioxidant (AO) and light-stabilizing properties of some substituted decahydroquinoxalinone s (3) . 1

1

, 0

0

.

HN N - CH CH - N NH 2

H

'

2

1

R* | Cj^-N^R HR

Dr. Layer has given one plausible explanation as to how 3 performs as an AO. The structural parameters of 3 will also be probed to locate the origins of its activity. 2

0097-£156/85/0280-0091$06.00/0 © 1985 American Chemical Society Klemchuk; Polymer Stabilization and Degradation ACS Symposium Series; American Chemical Society: Washington, DC, 1985.

92

POLYMER STABILIZATION A N D

DEGRADATION

1,1 -(1,2-Ethanediyl)bis(3,3,5,5-tetramethyl-2-piperazinone) (2) ( p i p e r a z i n e ) was p r e p a r e d from a n o v e l s y n t h e s i s u s i n g e a s i l y a v a i l a b l e raw m a t e r i a l s : 1

3

HC 3

CH J N0

HC H H CH yCH NCH CH NCH -/ H C* CH

3

3

+

(CH 0) 2

+ H2NCH2CH2NH2 — >

2

X

2

2

3

2

1

2

3

3

N0

N0

2

2


4

N

+

H

2

—

H C H H CH \-CH NCH CH NCH -4— C H 3

•

H

5 + CHC1

NaOH

0 3

J N a U n

+

HoC

3

2

3

NH

C

2

2

2

NH

2

H3C ^ 3 ^ 0 >

2

oJb^-

HN ' ^ N - C H C H - N

CHQ

2

H C 3

CH

C H

3

NH

2

H

3

3

3

C

C H

3

piperazine 2 P i p e r a z i n e HALS 2 i s a c o l o r l e s s c r y s t a l l i n e s o l i d which m e l t s at 134-6°C. I t i s a p o w e r f u l UV s t a b i l i z e r f o r p o l y o l e f i n s as i l l u s t r a t e d i n the outdoor aging data i n i s o t a c t i c polypropylene tapes.

2x100 m i l S l i t Tapes - A r i z o n a Aged F a i l u r e = Months t o 50% Loss o f T e n s i l e

0.1 p h r HALS +

AO-1 AO-2 A0-3 A0-4

Piperazine

Piperidine

9 10 12 8

5 6 10 3

Polymeric Piperidine

A O ' s a r e added a t 0 . 1 p h r . P i p e r i d i n e : Bis(2,2,6,6-tetramethyl4 - p i p e r i d i n y l ) decanedioate; Polymeric p i p e r i d i n e : Poly[[6[(l,l,3,3-tetramethylbutyl)amino]-l,3,5-trizaine-2,4-diyl(2,2,6,6tetramethyl-4-piperidinyl)imino-1,6-hexanediyl-(2,2,6,6-tetramethyl4-piperidinyl)imino] A0-1: l,3,5-Tris(3,5-di-t-butyl-4-hydroxyphenyl)methyl-l,3,5triazine-2,4,6-(lH,3H,5H)-trione. AO-2: Tris 2-[p-(3,5-di-t-butyl-4-hydroxyphenyl)propionoxy]ethyl isocyanurate. A0-3: Octadecyl 3,5-di-t-butyl-4-hydroxybenzenepropionate. AO-4: Pentaerythritol tetrakis-[0-(4-hydroxy-3,5-di-t-butylphenyl) propionate].

Klemchuk; Polymer Stabilization and Degradation ACS Symposium Series; American Chemical Society: Washington, DC, 1985.

7.

LAI ET AL.


0.25

93

Hindered Diazacycloalkanones

phr HALS +

AOA0A0AO-

Piperazine

Piperidine

Polymeric Piperidine

15 17 21 14

13 15 19 15

13 15

Piperazine 2 i s also highly synergistic with commercial UV absorbers, as shown i n 20 m i l - t h i c k compression-molded polypropylene samples aged i n a xenon Weather-Ometer.

• = 0.25 phr piperazine = 0.25 phr benzophenone = 0.125 phr piperazine + 0.125 phr benzophenone benzophenone: 2-hydroxy4-octyloxybenzophenone A

80-

0

IOOO 2000 3000 4000 HOURS in XENON WEATHER-OMETER

0.25 phr piperazine = 0.25 phr benzotriazole = 0.125 phr piperazine + 0.125 phr benzotriazole benzotriazole: 2-(2-hydroxyl-3,5-di-t-butylphenyl)-5chloro-2H-benzotriazole A

0

1000 2000 3000 4000 HOURS in XENON WEATHER-OMETER Piperazine HALS 2 has a p o s i t i v e effect on the processing s t a b i l i t y of polypropylene when used i n conjunction with a phenolic antioxidant:


POLYMER STABILIZATION AND DEGRADATION

94

16

X - Q

12

00


— CO

.

J — CO

UJ

02 05 0.10 0.50 _|

E x t r u s i o n Passes 2 a l s o has a v e r y lene f i l m s :

favorable

water

at

piperazine piperazine piperazine piperazine

270°C

carryover behavior

i n polypropy-

F i l m Speed

Additive

1. 2. 3.

phr phr phr phr

(ft/min)

134 78.5 150.5

Benzophenone P i p e r i d i n e HALS P i p e r a z i n e HALS

PP c o n t a i n i n g 0.1 p h r a d d i t i v e was e x t r u d e d a t 260°C i n t o a 5 m i l f i l m t h a t was quenched i n a 3 7 . 8 ° C water b a t h . Tachometer measurements o f the f i l m speed a t the p o i n t o f water c a r r y o v e r was recorded. The h i g h e r the number, the f a s t e r t h e p r o d u c t i o n would b e , which i s p r e f e r r e d .

I n the second p a r t o f t h i s p r e s e n t a t i o n , we would l i k e t o i n t r o d u c e a n o t h e r f a m i l y o f amine s t a b i l i z e r s . Namely, d e c a h y d r o q u i n o x a l i n e s 3 (R,R =alkyl) w h i c h not o n l y show l i g h t - s t a b i l i z i n g a c t i v i t y , b u t also antioxidation properties. f

C^^N-^p R

C x ^ N ^ - iC H

H

H H

R

CH CH

3

3

3 i s p r e s e n t as a m i x t u r e o f c i s - and t r a n s - i s o m e r s . Cis-3,3dimethyl-decahydroquinoxalin-2-one (6) i s a known compound while 3


7.

95

Hindered Diazacycloalkanones

LAI ET AL.

a l l trans-3 are n o v e l . 3 (R =H) c a n be s y n t h e s i z e d from two d i f f e r e n t routes^*: a) from t h e c o n d e n s a t i o n o f 1 , 2 - d i a n r i n o c y c l o h e x a n e and a ketone c y a n o h y d r i n i n h o t w a t e r , o r b) from t h e r e a c t i o n among DCH, k e t o n e , c h l o r o f o r m , and b a s e . !


/ ^ N H

a

2

HO

+

CN

J

fY^f

^

H

NH

+ CHC1

NH

0 II

2

3

+ R

2

NaOH "*" ^

R

3 (R'=H)

J 1

R

C i s - and t r a n s - 3 a r e e a s i l y s e p a r a b l e by an a c e t o n e wash, s i n c e t h e t r a n s - i s o m e r i s i n s o l u b l e i n almost a l l s o l v e n t s w h i l e t h e cis-isomer i s easily soluble. 3 ( R ' = H ) , e i t h e r as t h e p u r e isomer o r as a m i x t u r e , was t h e n a l k y l a t e d w i t h v a r i o u s a l k y l a t i n g agents t o g i v e 3 (R* = a l k y l , a l k y l e n e , e t c . ) . R

H

f

R

As a p a r t i a l l y h i n d e r e d amine, 3 showed light-stabilizing activity lower t h a n t h a t o f p i p e r a z i n e o r p i p e r i d i n e HALS, b u t comparable t o commercial benzophenones. L i k e HALS, t h e y a r e s t r o n g l y s y n e r g i s t i c w i t h benzophenones and b e n z o t r i a z o l e s i n p o l y o l e f i n s . L i g h t - S t a b i l i z i n g A c t i v i t y of 3 Formulations

1. 2. 3. 4. 5.

a

(phr)

3 (0.15) Benzophenone ( 0 . 1 5 ) B e n z o t r i a z o l e (0.15) 3 ( 0 . 0 7 5 ) + Benzophenone ( 0 . 0 7 5 ) 3 (0.075) + B e n z o t r i a z o l e (0.075)

H r s . to F a i l u r e

b

1250 1260 2100 2540 2830

20 m i l PP p l a q u e s c o n t a i n i n g 0.1 p h r A 0 - 2 50% t e n s i l e l o s s from a g i n g i n xenon Weather-Ometer®

More s u p r i s i n g t o us i s t h e a n t i o x i d a t i o n a c t i v i t y o f 3 i n polypropylene. Not o n l y s t r o n g p r i m a r y a n t i o x i d a n t s by t h e m s e l v e s , they are h i g h l y s y n e r g i s t i c w i t h other p h e n o l i c A O ' s .


96

POLYMER STABILIZATION AND DEGRADATION Oven-aging of 3 i n Polypropylene at 125°C Days 10 m i l 20 m i l


Formulations (phr) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

AO-1 (0.1) A0-1 (0.25) AO-2 (0.1) AO-2 (0.25) 3 a (0.1) 3a,(0.25) 3b (0.1) 3b (0.25) A0-1 (0.125) A0-1 (0.125) A0-1 (0.125) AO-1 (0.125) a

D

3a:

+ + + +

DSTDP (0.125) DSTDP (0.25) 3a (0.125) 3b (0.125) C

R = -CH -

Hindered Diazacycloalkanones as Ultraviolet Stabilizers and

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