Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2~
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A- 1 8537/A
Stabilised polvmer mixture
The present invention relates to photostabilised polymer mix[ures.
The use of light stabilisers, in particular sterically hindered amines, for stabilising
polymers against degradation by light is described in a number of publications. However,
it is also known that sterically hindered amines are unsuitable for photostabilisation of
certain polymers, due to the reactivity of such polymers towards bases. A known example
of a polymer which cannot be stabilised by sterically hindered amines is polycarbonate.
Surprisingly, it has now been found that even polymers which are reactive towards bases
can be stabilised against photodegration by sterically hindered amines if the latter are in a
suitable form and are admixed, in this form, with the polymers to be stabilised. Amines in
this form can also be used for stabilising polymers which can be protected in a
conventional manner by means of sterically hindered amines.
The present invention thus relates to a polymer mixture which comprises (a) a copolymer
made from styrene or o~-methylstyrene and at least one comonomer, where the copolymer
contains crosslinked elastomer particles which have been modifled by copolymerisation
with an unsaturated derivative of a sterically hindered amine, and (b) a thermoplastic
polymer.
The present invention also relates to a process for the preparation of a polymer mixture
according to the invention and to the use of the above-defined component (a) forstabilising polymers against photodegradation.
Component (a) in the polymer mixture according to the invention has been disclosed in
EP-A-337 431 and is preferably a graft copolymer of styrene or o~-methylstyrene and at
least one comonomer on the modified crosslinked elastomer.
The comonomer may be any polymerisable, unsaturated compound, for example an
acrylic acid, methacrylic acid or maleic acid derivative or a styrene derivative. Preferred
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comonomers are acrylonitrile and alkyl acrylates and alkyl methacrylates having 1 to 4
carbon atoms in the alkyl moiety, in particular methyl acrylate and methyl methacrylate. It
is also possible to use two comonomers, for example mixtures of acrylonitrile and methyl
methacrylate or mixtures of acrylonitrile or methyl methacrylate and small amounts of
vinyl acetate, butyl acrylate or a maleate.
The copolymer is preferably made from styrene and acrylonitrile or styrene and methyl
methacrylate.
The elastomer can be any elastomer which is suitable for graft copolymerisation reactions.
Examples are polybutadiene, butadiene-acrylonitrile copolymers, butadiene-styrene
copolymers, ethylene-propylene-diene terpolymers and polybutyl acrylate and its
copolymers. The elastomer is preferably polybutadiene. These elastomer particles are
prepared by known processes, such as by bulk polymerisation or suspension
polymerisation, but in particular by emulsion polymerisation. The elastomer particles are
weakly crosslinked and generally have a mean diameter of from 0.1 to 50 ~Im, preferably
from 0.5 to 5 ~,Im.
The modification of the elastomer by means of the sterically hindered amine is carried out
by copolymerisation or grafting. The copolymerisation can be carried out during the
preparation of the elastomer or as a graft polymerisation on the crosslinked elastomer. The
grafting with the sterically hindered amine can be carried out at the same time as the
grafting with the styrene/comonomer mixture. This is preferably carried out in two steps
by first grafting on the unsaturated derivative of the sterically hindered amine and
subsequently the styrene/comonomer mixture. The graft polymerisation is preferably
carried out in emulsion.
The unsaturated derivative of a sterically hindered amine is preferably a copolymerisable,
unsaturated derivative of 2,2,6,6-tetramethylpiperidine. The unsaturated group here may
be in a substituent in the 4-position and/or 1-position of the piperidine ring. Examples of
unsaturated groups are, in particular, acryloyl and methacryloyl groups, furthermore
maleic acid groups, vinyl ether and allyl ether groups, allylamino groups and crotonyl
groups.
The copolymerisation with the elastomer is preferably carried out using a compound of the
formula I
- 3 -
R 1~- C--X ~;--R2 ]
~CH3 n
in which n is 1 or 2;
X is -0- or-N(R3)-;
Rl, in the case where n = 1, is Cl-CI8alkyl, C2-C20alkenyl, Cs-C8cycloalkyl,
C7-C9phenylalkyl, phenyl, phenyl which is substituted by halogen, C1-C4alkyl or
Cl-C4alkoxy, or an R400C-CH=CH- group, and, in the case where n = 2, is
C2-C1Oalkylene, vinylene, C6-C12arylene or cyclohexylene;
R2 is hydrogen, Cl-C12alkyl, C3-Csalkenyl, C7-C9phenylalkyl, C1-C18alkoxy, -0-,
Cs-C8cycloalkoxy, C7-C9phenylalkoxy, C2-CIOalkanoyl, C3-C6alkenoyl or a group of the
formula m
Rs o R6
11 1
-CH2-CH-O-C-C=CH2 III
R3 is hydrogen, C1-C12alkyl or Cs-C8cycloalkyl;
R4 is hydrogen or Cl-Cl2alkyl;
Rs is hydrogen, CH3 or CN, and
R6 is hydrogen, Cl-CI2alkyl or phenyl,
where at least one of the substituents R1 and R2 contains an ethylenic double bond.
It is also preferred to use the compounds of the forrnula II
O H~<cH3
~N ~ N--R2 II
O H~7<CH3
in which R2 is hydrogen, Cl-Cl2alkyl, C3-C5alkenyl, C7-C9phenylalkyl, Cl-C18alkoxy,
-0-, Cs-C8cycloalkoxy, C7-C9phenylalkoxy or C2-ClOalkanoyl.
,, . . , . .. ~ ..... .. . -
4 2~L~"7
Of the compounds of the formula I, preference is given to
a) those in which n is 1, X is -O-, Rl is C2-C5alkenyl and R2 is hydrogen, Cl-C4alkyl,
allyl, benzyl or acetyl,
b) those in which n is 1 or 2, X is -O-, Rl, in the case where n = 1, is Cl-Cl8alkyl,
cyclohexyl or phenyl and, in the case where n = 2, is C2-C8alkylene, and R2 is
C3-C6alkenoyl, and
c) those in which n is 1, X is -O-, Rl is C2-Csalkenyl and R2 is a group of the formula III
in which Rs and R6 are hydrogen or CH3.
Palticular preference is given to 1,2,2,6,6-pentamethyl-4-acryloyloxypiperidine.
In these formulae, alkyl Rl, R2, R3, R4 and R6 may be linear or branched. Examples are
methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, telt-butyl, isopentyl, n-hexyl,
n-octyl, 2-ethylhexyl, n-decyl, isoundecyl and n-dodecyl. Alkyl Rl may also be, for
example, tetradecyl, hexadecyl or octadecyl.
C2-CsAlkenyl Rl may be, for example, vinyl, propenyl, isopropenyl, butenyl or pentenyl,
in palticular vinyl or 2-propenyl (isopropenyl). C3-CsAlkenyl R2 is preferably allyl.
Cs-C8Cycloalkyl Rl and R3 may be, for example, cyclopentyl, cyclohexyl or cyclooctyl,
but in patticular cyclohexyl.
C7-C9Phenylalkyl Rl and R2 may be, for example, benzyl, phenylethyl or phenylpropyl,
but in palticular benzy1.
Cl-Cl8Alkoxy R2 may be, in particular, C6-CIOalkoxy, Cs-C8cycloalkoxy R2 may be, in
particular, cyclohexyloxy and C7-Cgphenylalkoxy R2 may be, in particular, benzyloxy or
phenylethoxy.
C2-CIOAlkanoyl R2 may be, for example, acetyl, propionyl, butyroyl, isobutyroyl,n-pentanoyl, tert-pentanoyl, hexanoyl, octanoyl or isodecanoyl, but in particular acetyl.
C3-C6Alkenoyl R2 is, in particular, acryloyl or methacryloyl.
2~ ''7
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C2-ClOAlkylene Rl may be, for example, di-, t~i-, tetra-, hexa-, octa- or decamethylene,
2,2-dimethyltrimethylene or 1,3,3-trimethyltetramethylene.
C6-CI2Arylene Rl may be, for example, phenylene, naphthylene or diphenylene, in
particular phenylene.
All the compounds of the formulae I and II contain at least one ethylenic double bond,
which makes the compounds capable of copolymerisation. However, it is also possible for
the compounds to contain two double bonds. Such compounds are preferably
copolymerised during the preparation of the elastomer.
Examples of compounds of the formula I are:
1,2,2,6,6-pentamçthyl-4-piperidinyl acrylate, methacrylate and crotonate,
2,2,6,6-tetramethyl-4-piperidinyl acrylate, methacrylate and crotonate,
l-allyl-2,2,6,6-tetramethyl-4-piperidinyl acrylate, methacrylate and crotonate,
1-benzyl-2,2,6,6-tetramethyl-4-piperidinyl acrylate, methacrylate and crotonate,N-(2,2,6,6-tetramethyl-4-piperidinyl)acrylamide, N-methyl-N-(1,2,2,6,6-
pentamethyl-4-piperidinyl)methacrylamide, N-butyl-N-(1,2,2,6,6-pentamethyl-
4-piperidinyl)acrylamide, monoethyl mono(1,2,2,6,6-pentamethyl-4-piperidinyl) maleate,
di(2,2,6,6-tetramethyl-4-piperidinyl) fumarate, monohexyl N-(2,2,6,6-tetramethyl-
4 piperidinyl)-N-butylmaleimide, N,N'-di(1,2,2,6,6-pentamethyl-4-piperidinyl)-
N,N'-dibutylmaleimide, 1-acryloyl-2,2,6,6-tetramethyl-4-acetoxypiperidine,
1-methacryloyl-2,2,6,6-tetramethyl-4-butyroyloxypiperidine, 1-crotonyl-2,2,6,6-tetra-
methyl-4-benzoyloxypiperidine, 1-acryloyl-2,2,6,6-tetramethyl-4-acryloyloxypiperidine,
1-methacryloyl-2,2,6,6-tetramethyl-4-methacryloyloxypiperidine, 1-acryloyl-2,2,6,6-tetra-
methyl-4-(4-chlorobenzoyloxy)piperidine, di(1-acryloyl-2,2,6,6-tetramethyl-4-piperidinyl)
sebacate, di(1-methacryloyl-2,2,6,6-tetramethyl-4-piperidinyl) adipate, di(l-acryloyl-
2,2,6,6-tetramethyl-4-piperidinyl) succinate, di(l-crotonoyl-2,2,6,6-tetramethyl-
4-piperidinyl) phthalate, N-(l-acryloyl-2,2,6,6-tetramethyl-4-piperidinyl)acetamide,
N-(1-acryloyl-2,2,6,6-tetramethyl-4-piperidinyl)-N-butylbenzamide, N,N'-di(l-meth-
acryloyl-2,2,6,6-tetramethyl-4-piperidinyl)-N,N'-dicyclohexylisophthalamide,
1-(2-acryloyloxyethyl)-4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 1-(2-methacryloyl-
oxyethyl)-4-methacryloyloxy-2,2,6,6-tetramethylpiperidine and 1-(2-acryloyloxypropyl)-
4-acryloyloxy-2,2,6,6-tetramethylpiperidine.
Z~ ''7
Examples of compounds of the formula II are:
N-(2,2,6,6-tetramethyl-4-piperidinyl)maleimide, N-(1,2,2,6,6- pentamethyl-
4-piperidinyl)maleimide, N-(1-benzyl-2,2,6,6-tetra methyl-4-piperidinyl)maleimide and
N-(l-acetyl-2,2,6,6- tetramethyl-4-piperidinyl)maleimide.
However, the unsaturated derivatives, which can be used according to the invention, of
sterically hindered amines are in no way restricted to compounds of the formulae I and II.
In principle, any unsaturated derivative of a sterically hindered amine can be used so long
as it is capable of copolymerisation with elastomer components.
The unsaturated, sterically hindered amine can be copolymerised alone or together with
other unsaturated compounds. Examples of such comonomers are alkyl acrylates, alkyl
methacrylates, acrylamides, methacrylamides, acrylonitrile and methacrylonitrile.
The mixture of styrene or a-methylstyrene and the comonomer can be grafted onto the
elastomer particles together with the unsaturated derivative of a sterically hindered amine.
The graft copolymerisation is preferably carried out in two steps. In the first step, the
unsaturated, sterically hindered amine is grafted, alone or together with other unsaturated
compounds, onto the elastomer. In a second step, the mixture of styrene or
a-methylstyrene and the comonomer is grafted onto the product from the first step.
Alternatively, the elastomer particles grafted with the unsaturated, sterically hindered
amine can be mixed, in a second step, with a separately prepared styrene or
a-methylstyrene copolymer. However, the styrene phase is preferably grafted onto the
modif1ed elastomer.
Obviously, the unsaturated, sterically hindered amine reacts with double bonds present on
the crosslinked elastomer particles. The grafting takes place on the surface of the
elastomer beads, it being possible for the grafted amine to completely or partially envelop
the elastomer particle. If, in addition, styrene and the comonomer, for example an
acrylonitrile, are then grafted on, the entire elastomer particle is enveloped and any free
areas on the surface of the elastomer particle are also occupied (= component (a)). In this
way, direct contact between amine and thermoplastic polymer (= component (b)) isavoided.
.
- 7 - 2~ ~7
Electron photomicrographs clearly show the core/shell structure of the envelopedelastomer particles, but no distinction is possible between the amine and the styrene
copolymer.
, ,
. ~
2g?~
The copolymerisation or graft copolymerisation is carried out by conventional processes.
For details, see, for example, the abovementioned EP-A-337 431, in which it is
furthermore stated that other known stabilisers, for example antioxidants, UV absorbers
and further light stabilisers, and also the additives customary in plastics technology, such
as pigments, fillers, reinforcing agents and lubricants, etc, can also be added to the
copolymers stabilised in this way.
Examples of suitable compounds for component (b) are:
1. Halogen-containing polymers, in particular polymers made from halogen-containing
vinyl compounds, for example polyvinyl chloride, polyvinylidene chloride, polyvinyl
fluoride, polyvinylidene fluoride; and copolymers thereof, such as vinyl
chloride-vinylidene chloride, vinyl chloride-vinyl acetate and vinylidene chloride-vinyl
acetate.
2. Polymers derived from ~"B-unsatura~ed acids and derivatives thereof, such as
polyacrylates and polymethacrylates, polyacrylamides and polyacrylonitriles.
3. Polymers derived from unsaturated alcohols and amines or their acyl derivatives or
acetals, such as polyvinyl alcohol, polyvinyl acetate, stearate, benzoate and maleate,
polyvinylbutyral, polyallyl phthalate and polyallylmelamine.
4. Homopolymers and copolymers of cyclic ethers, such as polyalkylene glycols,
polyethylene oxide, polypropylene oxide and copolymers thereof with bisglycidyl ethers.
5. Polyacetals, such as polyoxymethylene, and polyoxymethylenes containing
comonomers, eg. ethylene oxide, and polyacetals which have been modified by means of
thermoplastic polyurethanes, acrylates or MBS.
6. Polyphenylene oxides and sulfides, and mixtures thereof with styrene polymers or
polyamides.
7. Polyurethanes derived from polyethers, polyesters or polybutadienes containing
terminal hydroxyl groups on the one hand and aliphatic or aromatic polyisocyanates on the
other hand, and precursors thereof.
2~ ~ ~"7
g
8. Polyamides and copolyamides derived from diamines and dicarboxylic acids and/or
from aminocarboxylic acids or the corresponding lactams, such as nylon 4, nylon 6, 6/6,
6/10, 6t9, 6/12, 4/6, 11 and 12, aromatic polyamides prepared from m-xylene, a diamine
and adipic acid; polyamides prepared from hexarnethylenediamine and iso- and/or
terephthalic acid and if desired an elastomer as modifier, eg.
poly-2,4,4-trimethylhexamethyleneterephthalamide or poly-m-phenylene isophthalamide.
9. Polyureas, polyimides, polyamide-imides and polybenzimidazoles.
10. Polyesters derived from dicarboxylic acids and dialcohols and/or from
hydroxycarboxylic acids or the corresponding lactones, such as polyethylene
terephthalate, polybutylene terephthalate, poly- 1,4-dimethylolcyclohexane terephthalate,
polyhydroxybenzoates, and block polyether-esters derived from polyethers containing
hydroxyl terminal groups; and furthermore with polycarbonates or MBS-modified
polyesters.
11. Polycarbonates and polyester carbonates.
Component (b) is preferably a polymer which can only be stabilised with difficulty, or not
at all, by means of sterically hindered amines, such as polycarbonate, polyamide,
polyester, in particular polybutadiene terephthalate, polyvinyl chloride, polyphenylene
ether, thermoplastic polyurethane or styrene-maleic anhydride copolymer, or mixtures of
said polymers. Component (b) is in particular polycarbonate.
The proportions of component (a) and (b) in the polymer mixture according to theinvention may vary within broad limits. Component (a) preferably makes up from 5 to
95 per cent by weight, in particular from 10 to 50 per cent by weight, of the polymer
mixture.
It may be advantageous for other, known stabilisers to be added to the polymer mixture.
Examples of these are stabilisers from the following classes:
1. Antioxidants
1.1 Alkvlated monophenols, for example 2,6-di-tert-butyl-4-methylphenol,
2~ 7
- 10 -
2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol,
2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-i-butylphenol,
2,6-dicyclopentyl-4-methylphenol, 2-(a-methylcyclohexyl)-4,6-dimethylphen
2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,
2,6-di-tert-butyl-4-methoxymethylphenol and 2,6-dinonyl-4-methylphenol.
1.2. Alkylated hvdroquinones, for example 2,6-di-tert-butyl-4-methoxyphenol,
2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone and
2,6-diphenyl-4-octadecyloxyphenol.
1.3. Hydroxylated dipheny! thioethers, for example
2,2'-thiobis(6-tert-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol),
4,4'-thiobis(6-tert-butyl-3-methylphenol) and 4,4'-thiobis(6-tert-butyl-2-methylphenol).
1.4. Alkvlidenebisphenols, for example 2,2'-methylenebis(6-tert-butyl-4-methylphenol),
2,2'-methylenebis(6-tert-butyl-4-ethylphenol),
2,2'-methylenebis[4-methyl-6-(a-methylcyclohexyl)phenol],
2,2 '-methylenebis(4-methyl-6-cyclohexylphenol),
2,2'-methylenebis(6-nonyl-4-methylphenol), 2,2'-methylenebis(4,6-di-tert-butylphenol),
2,2'-ethylidenebis(4,6-di-tert-butylphenol),
2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol),
2,2'-methylenebis[6-(a-methylbenzyl)-4-nonylphenol],
2,2'-methylenebis[6-(a,a-dimethylbenzyl)-4-nonylphenol],
4,4'-methylenebis(2,6-di-tert-butylphenol),
4,4'-methylenebis(6-tert-butyl-2-methylphenol),
1, 1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,
2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,
1, 1 ,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,
1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane, ethylene
glycol bis[3,3-bis(3'-tert-butyl-4'-hydroxyphenyl) butyrate],
bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene and
bis[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphenyl]
terephthalate.
1.5. Benzyl compounds, for example
1 ,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,
z~
bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, isooctyl
3 ,S -di-tert-butyl-4-hydroxybenzylmercaptoacetate,
bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithiol terephthalate,
1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate,
1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, dioctadecyl
3,5-di-tert-butyl-4-hydroxybenzylphosphonate, the calcium salt of monoethyl
3,5-di-tert-butyl-4-hydroxybenzylphosphonate, and
1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl) isocyanurate.
1.6. Acvlaminophenols, for example 4-hydroxylauranilide, 4-hydroxystearanilide,
2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino) -s-triazine and octyl
N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.
1.7. Esters of ~-(3~5-di-tert-butvl-4-hvdroxvphenvl)proPionic acid with monohydric or
polyhydric alcohols, for example with methanol, octadecanol, 1 ,6-hexanediol, neopentyl
glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol,
tris(hydroxyethyl) isocyanurate and N,N'-bis(hydroxyethyl)oxalamide.
1.8. Esters of ~-(S-tert-butvl-4-hvdroxy-3-methvlphenvl~proPionic acid with monohydric
or polyhydric alcohols, for example with methanol, octadecanol, 1 ,6-hexanediol,neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol,
pentaerythritol, tris(hydroxyethyl) isocyanurate and N,N'-bis(hydroxyethyl)oxalamide.
1,9. Esters of 1~-(3.5-dicvclohexvl-4-hvdroxvphenYl)proPionic acid with monohydric or
polyhydric alcohols, for example with methanol, octadecanol, 1 ,6-hexanediol, neopentyl
glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol,
tris(hydroxyethyl) isocyanurate and N,N'-bis(hydroxyethyl)oxalamide.
1.10 Amides of ~-(3.5-di-tert-butvl-4-hydroxvphenvl)propionic acid, for example
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine,
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine and
N,N' -bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.
2. UV absorbers and li~ht stabilisers
2.1. 2-(2'-Hydroxvphenyl)benzotriazoles, for example the S'-methyl, 3',5'-di-tert-butyl,
- 12-
5'-tert-butyl, 5'-~1,1,3,3-tetramethylbutyl), 5-chloro-3',5'-di-tert-butyl,
5-chloro-3'-tert-butyl-5'-methyl, 3'-sec-butyl-5'-tert-butyl, 4'-octoxy, 3',5'-di-tert-amyl
and 3',5'-bis(a,a-dimethylbenzyl) derivatives.
2.2. 2-Hvdroxybenzophenones, for example the 4-hydroxy, 4-methoxy, 4-octoxy,
4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy and
2'-hydroxy-4,4'-dimethoxy derivatives.
2.3 Esters of substituted or unsubstituted benzoic acids, for example 4-tert-butylphenyl
salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoylresorcinol,
bis(4-tert-butylbenzoyl)resorcinol, benzoylresorcinol, 2,4-di-tert-butylphenyl
3,5-di-tert-butyl-4-hydroxybenzoate and hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate.
2.4. Acrvlates, for example ethyl and isooctyl a-cyano-~,~-diphenylacrylate, methyl
a-carbomethoxycinnamate, methyl and butyl a-cyano-~-methyl-p-methoxycinnamate,
methyl a-carbomethoxy-p-methoxycinnamate and
N-(,~-carbomethoxy-,3-cyanovinyl)-2-methylindoline.
2.5. Nickel compounds, for example nickel complexes of
2,2'-thiobis[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or 1:2 complex, if desired
with additional ligands, such as n-butylamine, triethanolamine or
N-cyclohexyldiethanolamine, nickel dibutyldithiocarbamate, nickel salts of monoalkyl
esters of 4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid, such as of the methyl or ethyl
ester, nickel complexes of ketoximes, such as of 2-hydroxy-4-methylphenyl undecyl
ketoxime, nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyrazole, if desired with
additional ligands.
2.6. Stericallv hindered amines, for example bis(2,2,6,6-tetramethylpiperidyl) sebacate,
bis(l,2,2,6,6-pentamethylpiperidyl) sebacate, bis(l,2,2,6,6-pentamethylpiperidyl)
n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the product of the condensation of
l-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, the product of
the condensation of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and
4-tert-octylamino-2,6-dichloro- 1 ,3,5-s-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)
nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetraoate and
1,1 '-~1,2-ethanediyl)bis(3,3,5,5-tetramethylpiperazinone).
-13- 2~?~ 7
2.7. Oxalic acid diamides, for example, 4,4'-dioctyloxyoxanilide,
2,2'-dioctyloxy-S,S '-di-tert-butyloxanilide, 2,2'-didodecyloxy-5,5 ' -di-tert-butyloxanilide,
2-ethoxy-2'-ethyloxanilide, N,N'-bis(3-dimethylaminopropyl)oxalamide,
2-ethoxy-5-tert-butyl-2'-ethyloxanilide and the mixture thereof with
2-ethoxy-2'-ethyl-5,4'-di-tert-butyloxanilide, and mixtures of o- and p-methoxy- and of o-
and p-ethoxy-disubstituted oxanilides.
2.8. 2-(2-Hydroxyphenvl~-13.5-triazines, for example
2,4,6-tris(2-hydroxy-4-octyloxyphenyl)- 1 ,3,5-triazine,
2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)- 1 ,3,5-triazine,
2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)- 1 ,3,5-triazine,
2,4-bis(2-hydroxy-4-propoxyphenyl)-6-(2,4-dimethylphenyl)- 1 ,3,5-triazine,
2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine and
2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)- 1,3 ,S-triazine.
3. Metal deactivators, for example N,N'-diphenyloxalamide,
N-salicylyl-N'-salicyloylhydrazine, N,N'-bis(salicyloyl)hydrazine,
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine,
3-salicyloylamino-1,2,4-triazole and bis(benzylidene)oxalodihydrazide.
4. Phosphites and phosphonites, for example triphenyl phosphite, diphenyl alkyl
phosphites, phenyl dialkyl phosphites, tris(nonylphenyl) phosphite, trilauryl phosphite,
trioctadecyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)
phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)
pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis(2,4-di-
tert-butylphenyl) 4,4'-biphenylenediphosphonite, 3,9-bis(2,4-di-tert-butyl-
phenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.
5. Peroxide-destroving compounds, for example esters of ,3-thiodipropionic acid, for
example the lauryl, stearyl, myristyl and tridecyl esters, mercaptobenzimidazole, the zinc
salt of 2-mercaptobenzimidazole, zinc dibutyldithiocarbamate, dioctadecyl disulfide and
pentaerythritol tetrakis(,B-dodecylmercapto)propionate.
In addition, other assistants which are conventional in plastics technology can be added,
for example pigments, fillers, reinforcing agents, lubricants, flameprooflng agents,
antistatics or blowing agents.
- 14 -
As the further component (c) for the polymer mixture according to the invention, UV
absorbers, in particular, preferably the abovementioned
2-(2'-hydroxyphenyl)benzotriazoles, can be used successfully.
The preparation of the polymer mixtures according to the invention proceeds fromcomponents (a) and (b), which are mixed with one another in a conventional manner.
Component (a) is preferably prepared - as described in said EP-A-337 431 - by first
grafting an unsaturated derivative of a sterically hindered amine onto the elastomer
particles, grafting a mixture of styrene or oc-methylstyrene and at least one comonomer
onto the elastomer particles modified in this way, and admixing a thermoplastic polymer
with the resultant copolymer in a conventional manner.
The example below serves to illustrate the invention in greater detail. Ratios and
percentages are by weight.
Example 1: 933 g of polybutadiene latex (BR) having a solids content of 59 %
(Baystal~g) 2004 D), 848.5 g of demineralised water, 2.5 g of potassium persulfate and 0.1
g of tert-dodecyl mercaptan are introduced into a 3 I reactor, and the mixture is degassed
four times, stirred under argon at 100 rpm and warmed to 65C over the course of 30
minutes. The addition of 4-acryloyloxy-1,2,2,6,6-pentamethylpiperidine (APP) is then
commenced. All the APP (57.9 g) is added over about 1 hour. After a polymerisation time
of 3 hours, the latex is cooled to room temperature.
A potassium persulfate solution (5 g of potassium persulfate dissolved in 200 g of water)
is added to 1675 g of the resultant latex (= 500 g BR and 52.7 g APP) in a 3 I stirred
reactor, and the mixture is degassed four times and heated to 65C under argon over the
course of half an hour. 250 g of a 4 % aqueous emulsifier solution (Dresinate(~) 731) and
500 g of the monomer mixture of styrene and acrylonit.ile (2: 1) and 1 g of tert-dodecyl
mercaptan are metered in simultaneously over about 4 hours. When the addition iscomplete, the polymerisation is continued for a further hour at 65C and at a stirring speed
of 100 rpm.
6.45 g of an aqueous emulsion of the antioxidant of the formula
2~ ~'?7
H2C CH2CH2C02--CH2CH20CHZ~
are added to the resultant latex. The mixture is then filtered through glass wool.
In order to coagulate the latex, 5 1 of water and 20 g of acetic acid are heated to from 85 to
90C and added rapidly to the emulsion at a stirring speed of about 300 rpm. The mixture
is stirred at 90C for 10 minutes in order to complete the coagulation. The precipitated
copolymer is filtered off while hot, giving 950 g of ABS copolymer as a white powder
containing 5 % of incorporated APP.
This copolymer in powder form is mixed with the same amount of styrene-acrylonitrile
copolymer (suspension SAN, Ube Cycon) and a two-fold amount of pulverulent
polycarbonate (PC 135, General Electric), if desired with further additives, for example a
UV absorber, using aero wheels. The mixture is prepared in a twin-screw extruder(temperature cycle: 165C, 250C, 275C, 275C, 270C; 45 rpm).
The mixtures obtained are pressed in a hot press at 200C to give sheets with a thickness
of 2 mm. Test specimens measuring 40 x 40 x 2 mm are cut out of the sheets and are
exposed to UV light in a Weather-O-Meter WRC 600. Samples are taken at regular
intervals and measured for yellowing in accordance with ASTM D 1925.
The yellowing as a function of exposure time, expressed in ~YI (YI = yellowness index;
aYI = difference in the YI values between unexposed and correspondingly exposed
samples) and determined by the stated method, is shown in Table 1.
- 16-
Table 1:
_ .~
Additive ~ YI after an exposure time of
250 h 500 h 1000 h 1250 h 1500 h
none 1.1 6.8 15.2 20 22
0.3 % of UV absorber * -7.0 -3.0 7.5 12.1 14.9
1.25 % of grafted APP -2.3 1.3 7.9 13.4 15.9
_ . . ._ _ _ _
1.25 % of grafted APP
+ 0.3 % of UV absorber -13.3 -12.6 -4.5 2.9 6.6
(Percentages are based on the total polymer weigllt [component (a) and component (b)])
The UV absorber* of the formula
HO C(CH3)2C6Hs
N \ ~
C(CH3)2C6H5
serves as a comparison or is added to the powder mixture.
The compositions according to the invention have significantly higher stability to
yellowing than does the same polymer mixture, but without any graftcd APP.
Example 2: The ABS copolymer from Example 1, in powder forrn, is mixed with the same
amount of styrene-acrylonitrile copolymer (suspension SAN, Kostil, Montedipe~, if
desired with further additives, for example a UV absorber (Tinuvin 234, Ciba-Geigy AG)
and a phosphite (Irgafos 168, Ciba-Geigy AG), using aero wheels. The mixture is
processed in a twin-screw extruder (temperature cycle: 210C/210C/215C/220C) and
granulated.
The ABS granules obtained are mixed with the same amount of polycarbonate granules
(PC calibre, Dow). The polymer blend is prepared in a twin-screw extruder (temperature
2g~ 7
- 17-
cycle: 240C/240C/250C).
The resultant blends are pressed in a hot press at 200C to give sheets with a thickness of
2 mm. Test specimens measuring 40 x 40 x 2 mm are cut out of the sheets and exposed to
UV light in a Weather-O-Meter WRC 600. Samples are taken at regular intervals and their
yellowing (or yellowness index) is measured by the ASTM D 1925 method.
The yellowing is shown in Table 2 as a function of the exposure time.
Further test specimens measuring 12.7 x 60.0 x 2.0 mm are exposed to UV light in a
Xenotest 450. Samples are taken at regular intervals and their flexural impact strength is
measured by the ASTM D 4508-85 method. The pendulum impact takes place on the
exposed side of the sample.
Table 3 shows the energy required to fracture the sample. The higher this value, the
greater the flexural impact strength of the sample. In the case of undamaged samples, no
fracture takes place.
Table 2:
~ YI after an exposure time of
Additive 500 h1000 h 2000 h 3000 h4000 h
none 14 25 39
.._ . _
0.50 % of TINUVIN 234 -7 1.1 16.123.4 23.9
_ __
1.25 % of grafted APP 2
0.50 % of TINUVIN 234 -24.3 -16.8 -7.3 .3 3 o
- 18-
Table 3:
Flexural impact strength in kJ/m2 after
Additive 200 300 500 10001500 1800 200()
hours in the Xenotest 450
none 14_2 13+1
0.50 % of TINUVIN 234 n.f. 15_2 13+1 11+1 11+1
1.25 % of grafted APP
0.50% of TINUVIN234n.f.n.f. n.f. n.f. n.f. n.f. 60
_
n.f. = no fracture
Example 3: The ABS copolymer granules from Example 2 are mixed with the same
amount of polybutylene terephthalate (PBT CRASTIN S 600, Ciba-Geigy). The polymer
blend is prepared in a twin-screw extruder (temperature cycle:
210C1230C/235C/240C). Samples measuring 12.7 x 60.0 x 2.0 mm are
injected-moulded in an Arburg injection-moulding machine at a maximum processingtemperature of 260C and are aged in an oven at 200C and at 160C. Samples are taken
at regular intervals and their yellowing is measured in accordance with ASTM D 1925.
The results are shown in Tables 4 and 5:
Table 4:
Stabilisation ~ YI after oven ageing at 200C after
. _
10 min 20 min 40 min 60 min 90 min
none 5.6 20.1 37.4 49.5 61.6
0.50 % of TINUVIN 234 6.0 16.4 33.1 43.9 55.3
1.25 % of grafted APP 2.0 5.9 15.1 25.2 40.6
1.25 % of grafted APP 2.1 5.9 17.5 23.5 36.4
+ 0.50 % of TINUVIN 234
19
Table 5:
Stabilisation ~ YI after oven ageing at 160C after
60 min90 min120 minl~i0 min840 min
none ~ ~ 8.6 16.0 22.7 64.6
0.50 % of TINUVIN 234 ~ ~ 10.8 11.6 20 4 56.3
1.25 % of grafted APP 3.2 3.6 4.1 8 9 27.0
1.25 % of grafted APP 3.6 3.6 3.8 8.4 24.0
+ 0.50 % of TINUVIN 234
Example 4: Grafted ABS containing 5 % of APP is prepared as in Example 1 and mixed
with the same amount of polyvinyl chloride (PVC, SOLVIC SA 250, Solvay),4 % of alubricant (Loxiol VGS 1809, Loxiol G 70 S, Hoechst), 2 % of a heat stabiliser (D 26-376,
Ciba-Geigy AG) and if desired 0.25 % of a UV absorber (Tinuvin 320, Ciba-Geigy AG),
using aero wheels. The mixtures are processed in a two-roll mixer for 5 minutes at 175C.
The mixturçs obtained are pressed in a hot press at 180C to give sheets with a thickness
of 2 mm. Test speciments measuring 12.7 x 60 x 2 mm are cut out of the sheets and are
exposed to UV light in a Xenotest 450. Samples are taken at regular intervals and their
flexural impact strength is measured in accordance with ASTM D 4508-85. The pendulum
impact takes place on the exposed side of the sample.
The results are shown in Table 6.
2t~ 7
- 20-
Table 6:
Flexural impact strength in kJ/m2 after
Stabilisation an exposure time in the Xenotest 450 of
80 h 200 h350 h500 h 670 h 720 h
none n.f. 27+226+3 26+4 26+2 26+2
0.25 % of TINUVIN 320 n.f.n.f. 34+4 24+2 24+1 24+1
2.5% of graftedAPP n.f. n.f.n.f. n.f. 42+1 40~2
2.5 % of grafted APP
0.25 %of TINUVIN320 n.f. n.f.n.f. n.f. cr. 59_1
n.f. = no fracture
cr. =cracking
Further test specimens measuring 40 x 40 x 2 mm are exposed to UV-A light. Samples are
taken at regular intervals and the yellowing is measu;ed in accordance with ASTM D
1925.
The results are shown in Table 7.
Table 7:
a YI after a UV-A exposure time of
Stabilisation 24 h 100 h 170 h 340 h 600 h 770 h
..
none 13 28.536.7 46.5 56.3 62.9
_
2.5 % of grafted APP 8.5 18.3 25.1 35 44.6 48.1
2.5 % of grafted APP -1 8 -0.2 2.5 9.3 17.8 22 3
0.25 % of TINUVIN 320
Example 5: A grafted ABS is prepared as described under Example 1, with the exception
that 57.9 g of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine (MAPP) are employed
as stabiliser.
- 21 -
25 % of the ABS copolymer are mixed with 75 % of polyvinyl chloride (PVC, SOLVIC258 RB, Solvay), 4 % of a lubricant (Irgawax 368, Ciba-Geigy AG), 2 % of a heat
stabiliser (D 26-376, Ciba-Geigy AG) and if desired 0.25 % of a UV absorber (Tinuvin
320, Ciba-Geigy AG), using aero wheels. The mixtures are processed in a two-roll mixer
for 5 minutes at 175C. The mixtures obtained are pressed in a hot press at 180C to give
sheets with a thickness of 2 mm. Test specimens measuring 40 x 40 x 2 mm are cut out of
the sheets and are aged at 190C in an oven. Samples are taken at regular intervals and
their yellowing is measured in accordance with ASTM D 1925.
The results are shown in Table 8.
Table 8:
~ YI after oven ageing at 190C for
Stabilisation l5min30min 45min 60min 90 min 120min
.
none 16 27.1 42.2 47.6 52.977.5
..
1.25 % of grafted MAPP 26.3 82.1 131.1 147.5 black
1.25 % of grafted MAPP 25 3 67.6 112.2 120.3 121.7 black
0.25 % of TINUVIN 320
.~ . .
