Note: Descriptions are shown in the official language in which they were submitted.
~6~34
This invention relates to polyester compositions which have a
markedly enhanced resistance to weathering.
Broadly, these compositions can be thought of as an admixture
of a stabilizer and a polyester. The stabilizer can be one of three
specific types and the polyester can be one of three specific types.
The rirst polyester is compris2d of terephthalic acid, 1 to ;0
mole percent ethylene giycol, and 99 to 50 mole ?ercent 1,4-cvclohex~ne-
dimelhar.ol .
The second polyester is comprised of terephthalic acid, 1 to
50 mole percent 1,4-butanediol and 99 to 50 mole percent 1,4-cyclo-
hexanedimethanol.
The third polyester is comprised of terephthaiic acid, I to 50
mole percent 2,2-dimethyl-1,3-propanediol, and 99 to 50 mole percent
` 1,4-cyclohexanedimethanol.
The first type of stabilizer is a 2-hydroxyphenyl benzotriazole
type stabilizer corresponding to the structure
~ R~ ~herein
~1
Rl is a monovalent alkyl radical having 1 tc 18 carbon âtO...S.
and
R2 is -H, -Cl or a monovalent alkyl radical having 1 to 18
carbon atoms.
~ xamples of monovalent alkyl radicals having 1 to 1~ carbGn
atoms includes methyl, ethyl, n-propyl, n-butyl, tertiary butyl, 2, -
dimethylbutyl, 2,2-dimethylhexyl, n-pentyl, n-hexyl, 2-ethylhexyl, n-
octyl, 2,2-dimethyloctyl, n-nonyl, n-decyl, dodecyl, 2,2-dimethyldecyl,
stearyl, and the like.
30 A preferred species corresponds to the structure
_ ~ -
~3~3
t~ il
~ H3
and can be called 2-(2H-benzotriazol-2-yl)-p-cresol. This compound is
sold commercially under the name Tinuvin P by Ciba Geigy Chemical
Corpo~ation.
These compounds and thelr preparation are wel' knowr. -n the
art and are described in U.S. 3,004,896.
The second type of stabilizer is a 2-hydroxy benzophenone type
stabilizer correspo~ding to the structure
F~3 qH
R3-0~ -R~ wherein
R3 is -H, -OH, -Cl or an alkoxy group having 1 to 18 carbon
atoms, with the proviso that at least one R3 must be either
-OH or alkoxy.
Examples of alkoxy groups having 1 to 18 carbon atoms are
methyloxy, e~hyloxy, n-butyloxy, 2,2-dimethylhexyloxy, n-pentyloxy, 2-
ethylhexyloxy, heptyloxy, n-octyloxy, 2,2-dimethyldecyloxy, dodecyloxy,
ant the llke.
A preferred species corresponds to the structure
,0~1
~ OC12H2s
and can be called 4-(dodecyloxy)-2-hydroxybenzophenone. This co~ound
is sold commerclally under the name ~astman Inhibitor DO~P by Eastman
Che~ical Products, Inc.
These compounds and their preparation are well known in the
art and are described in U.S. 2,861,053.
The third type of stabilizer is a substituted ethylene type
3tabilizer corre6pondin~ to the structure
- 3 -
3~
R7~ C~`4 wherein
~9 \R4
R4 is -C~ or an alkyl acyloxy group having 1 to 8 carbon atoms
in the alkyl portion,
R5 is -~, a monovalent alkyl radical having 1 to 8 carbon
atoms or a phenyl radical,
~6 is -H, -Cl, a mono~alent alkyl radic~l having i to 8 carDcn
atoms or an alkyl acylo-xy group h~ving 1 to 8 carbon atcms in the
alkyl portion, and
R7 is an alkoxy group having 1 ~o 18 carbon atoms, a benzylo-.cy
group or a phenoxy Eroup.
Examples of monovalent alkyl radicals having 1 .o .~ carbon
atoms that can form the alkyl portion of the alkyl acyloxy group are
methyl, ethyl, n-propyl, n-butyl, 2,2-dimethylbutyl, 2,2-dimethylhexyl,
n-pentyl, n-hexyl, 2-ethylhexyl and n-octyl.
Examples of monovalent al~yl radicals having 1 to 8 carbon
atoms are methyl, ethyl, n-propyl, n-butyl, 2,2-dimethylbutyl, 2,2-
dimethylhexyl, n-pentyl, n-hexyl, 2-ethylhexyl and n-octyl.
: Examples of alkoxy groups having 1 to 18 carbon atoms are
~20 methyloxy, ethyloxy, n-butyloxy, 2,2-dimethylhexyloxy, n-pentyloxy,
ethylhexyloxy, n-octyloxy; 2,2-d~methyldecylo~y, and the like.
A preferred species corresponds to the structure
~ -OCH3
CH30-a~ ~CH=C
~= o \~CH 3
which can be called dimethgl p-methoxYbenzylidene~alonate. This compound
- is sold co~mercially as Cyasorb ~ 88 by American Cyanamid Co.
These compounds and their preparation are well known in the
art and are described in U.S. 3,706,701.
The compositions of this invention are described as "consisting
e~sentially of" the polyester and the stabilizer. By this term we mean
~L1)5~6S3~
these polyesters can contain other materials as long as the unobvious
weatherability properties are retained. For example, other dicarboxy'ic
acids and diols could be used if the resulting polyester retains the
unobvious weatherability properties of the polyester of the invention.
Examples of other dicarboxylic acids include isophthalic, adipic, azelaic,
succinic, glutaric and 2,6-naphthalene dicarboxylic acid. Also, conven-
tional additives for molded articles, such as antioxidants, other
stabilizers, plasticizers, pigments, flame retardants, ar.d the llke can
be incorporated into the composition of this invention as long as the
polyester retains unobvious weatherability properties.
The polyesters useful in this invention have an inherent
viscosity of at least 0.5, preferably at least 0.7 when measured at
25C. using 0.50 grams of polymer per 100 ml. of a solvent composed of
60 volumes of phenol and 40 volumes of tetrachloroethane.
The polyesters of this invention are broadly known and can be
prepared by a variety of processes such as direct condensation, acidolysis,
and ester interchange. Preferably the polyester is prepared by ester
interchange where the dimethyl ester of terephthalic acid and the two
glycols are reacted to form a mixture of the bis esters of the two glycois
and the mixture of bis esters is polycondensed at high temperature and
low pressure to form a high molecular weight polymer through elimin2t-0n
of the two glycols.
In this invention the range of the other glycol besides 1,4-
cyclohexanedimethanol is broadly 1 to 50, preferably 5 to 40 mole per-
cent. Obviously, the remaining moies of 1,4 cyclohexanedimethanol would
be 99 to 50, preferably 95 to 60 mole percent.
The admixture of the polyester and the stabilizer can be
for~ed using technology well known in the art. For example, pellets of
the polyester can be coated with powdered stabilizer and extruded.
Preferably, the stabilizer is coextruded from the polymerization reactor
; wherein the polyester is formed.
Broadly, the amount of stabilizer can be an amount sufficient
~D9~iS34
to achieve enhanced weatherability. In one embodiment the amount cf
stabilizer can be 0.1 to 5.0 weight percent, based on the weight of the
polyester. Preferably, 0.25 to 2.0 weight percent can be used.
The polyester of this invention can be prepared into useful
articles, such as window panes, by conventional extrusion equipment and
procedures.
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