Polyester compositions and molded articles therefrom

The subject invention relates to the polyester compositions being composed of (a) an aromatic polyester having the relative viscosity of 1.2 to 2.0, (b) an aromatic polycarbonate having the number average molecular weight of 10,000 to 80,000, and (c) a glycidyl-group containing copolymer consisting essentially of .alpha.-olefine and glycidyl ester of .alpha.,.beta.-ethylenically unsaturated carboxylic acid and having the melt index of 0.1 to 100. They are useful for manufacturing electric, electronic and automotive parts, being superior in flow property and melt stability on molding, as well as in mechanical properties particularly in impact and hot-air aging resistance. The compositions can be molded to form various articles by conventional molding methods.

FIELD OF ART 
The subject invention relates to the polyester compositions being superior 
in flow property and melt stability on molding, as well as in mechanical 
properties particularly in impact resistance and hot-air aging 
deterioration resistance, and to the molded articles therefrom. 
BACKGROUND ART 
Having superior characteristics, aromatic polyesters that are represented 
by polyethylene terephthalate and polybutylene terephthalates are 
extensively used for manufacturing electric, electronic and automotive 
parts for example. However, their uses do not increase because of their 
low impact resistances. Therefore, it has hitherto been proposed to blend 
therein various kinds of polymers such as butadiene rubbers and acrylic 
elastomers. Among these blending methods, those with the copolymers being 
composed of such monomers as .alpha.-olefin and glycidyl ester of 
.alpha.,.beta.-ethylenically unsaturated acid that are mentioned in 
Japanese Laid-Open Patent Publication (Kokai) No. 32045/1977 and the U.S. 
Pat. No. 4461871 are comparatively superior to the others in improving 
effect of impact resistance and melt stability on molding. Nevertheless, 
in these methods, there is a problem that molded articles deteriorate in 
the impact resistance by hot-air aging in an oven. Further, the blendings 
of aromatic polycarbonates and acrylic elastomers to polybutylene 
terephthalates that are proposed in Japanese Laid-Open Patent Publication 
(Kokai) 500870/1980 are not satisfiable in impact resistance despite small 
increase and inferior in melt stability. No method solving the 
above-mentioned problems has been found. 
DISCLOSURE OF THE INVENTION 
The object of the subject invention is to provide the aromatic polyester 
compositions being superior in flow property and melt stability on 
molding, as well as in mechanical properties particularly in impact 
resistance and hot-air aging resistance, and being useful for 
manufacturing electric, electronic and automotive parts, and their molded 
articles. 
The object is achieved by a polyester composition composed of: 
(a) an aromatic polyester having a relative viscosity of 1.2 to 2.0, 
(b) an aromatic polycarbonate having a number average molecular weight, of 
10,000 to 80,000, and 
(c) a glycidyl group containing a copolymer consisting essentially of 
.alpha.-olefin and glycidyl ester of .alpha..beta.-ethylenically 
unsaturated carboxylic acid and having a melt index of 0.1 to 100, 
wherein components (a) and (b) are present in a weight ratio in the range 
of between 99/1 and 1/99 respectively and the component (c) is present in 
an amount of from 1 to 80 parts by weight per total 100 parts by weight of 
components (a) and (b). 
The object is preferably attained by the above compositions containing an 
ethylene based copolymer composed of ethylene and an .alpha.-olefin having 
3 to 10 carbon atoms also. 
THE BEST FORMS TO PRACTICE THE INVENTION 
The subject invention will be described in further details hereinafter. 
The resins being used according to the subject invention contain aromatic 
polyesters and aromatic polycarbonates. 
The former are polymers or copolymers having aromatic rings in chains and 
prepared by condensing mainly aromatic dicarboxylic acid (or ester forming 
derivative) and diol (or their ester forming derivative). 
The above-mentioned aromatic dicarboxylic acids include terephthalic acid, 
isophthalic acid, ortho phthalic acid, 2,6-naphthalenedicarboxylic acid, 
1,5-naphthalenedicarboxylic acids, bis(p-carboxyphenyl)methane, 
anthracenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 
diphenyletherdicarboxylic acid, 1,2-bis(4-carboxyphenoxy)-ethane and so 
forth and ester forming derivatives thereof. 
The above-mentioned aromatic dicarboxylic acid may be replaced with 
aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic 
acid, dodecanedionic acid and so forth. Alicyclic dicarboxylic acids such 
as 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic and so 
forth and ester forming derivatives thereof, provided they are present in 
an amount of less than 40 mol percents based on the total acid component. 
The diols include the aliphatic diols having 2 to 10 carbon atoms such as 
ethylene glycol, propylene glycol, 1,4-butane diol, neopentyl glycol, 
1,5-pentane diol, 1,6-hexane diol, decamethylene glycol, 
cyclohexanedimethanol and their mixtures. Further the small amount of 
long-chain glycols having molecular weights in the range of 400 to 6,000 
such as polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene 
glycol and so forth as well as their mixtures can be copolymerized. 
Preferable aromatic polyesters according to the subject invention are 
polyethylene terephthalate, polypropylene terephthalate, polybutylene 
terephthalate; polyhexamethylene terephthalate, 
polycyclohexylenedimethylene terephthalate, polyethylene-2,6-nathalate and 
so forth. Most preferable thereamong are polybutylene terephthalate that 
has excellent mechanical strength. 
The aromatic polyesters should preferably have a relative viscosity of 1.2 
to 2.0, more preferably of 1.4 to 1.8 as measured by a 0.5 percent 
orthochlorophenol solutions at 25.degree. C. Insufficient mechanical 
strength is developed or no good luster surface moldings are obtained when 
they are less than 1.2 or more than 2.0 respectively. 
The aromatic polycarbonates according to to the subject invention are 
preperable by ester exchange or phosgene methods using dihydric phenol or 
its derivative. 
The dihydric phenols are represented by the following formula: 
##STR1## 
wherein Ar' denotes an aromatic group such as phenylene, biphenylene and 
naphthylene; Z denotes an alkyl group such as methyl and ethyl, a 
halogenated alkyl group, an aryl group such as phenyl and naphthyl, a 
halogenated aryl group, aralkyl group such as benzyl and phenylethyl, a 
halogenated aralkyl group, or an alicyclic group; Y denotes an alkylene 
group such as methylene and ethylene, an alkylidene group such as 
ethylidene and isopropylidene, a tertiary amino group, O, S, SO, SO.sub.2, 
CO or an amide group; m and n are integers from 0 to 4; p is integer at 
least 1; q is 0 or 1; or r is 0 or positive integer. When q is o, r is o. 
Illustrative of the dihydric phenols are; 
bis(4-hydroxyphenyl)-methane; 
1,1-bis(4-hydroxyphenyl)-ethane; 
1,2-bis(4-hydroxyphenyl)-ethane; 
2,2-bis(4-hydroxyphenyl)-propane; 
1,1-bis(4-hydroxyphenyl)-propane; 
2,2-bis(4-hydroxy-3-chlorophenyl)-propane; 
2,2-bis(4-hydroxy-3,5-dichlorophenyl)-propane; 
2,2-bis(4-hydroxy-3-bromophenyl)-propane; 
2,2-bis(4-hydroxy-3,5-dibromophenyl)-propane; 
2,2-bis(4-hydroxy-3-methylphenyl)-propane; 
2,2-bis(4-hydroxy-3-methoxyphenyl)-propane; 
1,4-bis(4-hydroxypyenyl)-cyclohexane; 
1,1-bis(4-hyroxyphenyl)-cyclohexane; 
1,2-bis(4-hydroxyphenyl)-ethylene; 
1,4-bis(4-hydroxyphenyl)-benzene; bis(4-hydroxyphenyl)-phenylmethane; 
bis(4-hydroxyphenyl)-diphenylmethane; 
1,1-bis(4-hydroxyphenyl)-2,2,2-trichloroethane; 
bis(4-hydroxyphenyl)-ketone; bis(4-hydroxyphenyl)-sulfide; 
bis(4-hydroxyphenyl)-sulfone; 4,4'-dihydroxydiphenyl ether; 
4,4'-dihydroxybiphenyl; 3,3'-dihydroxybiphenyl; 
hydroquinone; resorcinol; 2,6-dihydroxynaphthalene; 
2,7-dihydroxynathalenes; phenophthalein; and so forth. 
Thereamong bis(4-hydroxyphenyl)alkane is preferable and 
2,2-bis(4-hydroxyphenyl)-propane is especially preferable. More than two 
dihydric phenols are usable in combination. They may be used together with 
the small quantities of alicyclic diols such as 1,4-cyclohexane diol, 
aliphatic diols such as 1,6-hexane diol, aromatic group containing 
aliphathic diols such as p-xylene glycol and so forth or can be end-capped 
by monohydric phenols such as phenol and p-tert-butylphenol. 
The aromatic polycarbonate has the number-average molecular weight of 
10,000 to 80,000, preferably of 15,000 to 40,000. The compositions can 
neither obtain enough mechanical properties nor hot-air aging resistance 
if it is less than 10,000 or inferior in moldability and mechanical 
properties if they are more than 80,000. 
The aromatic polyester and aromatic polycarbonate according to the subject 
invention are present in a weight ratio in the range between 99/1 and 
1/99,preferably between 80/20 and 20/80. respectively. On the contrary the 
synergistic effect for the increase in impact resistance of polyester 
compositions and the resulting increase in hot-air aging resistance are 
small except in the above-mentioned ranges. 
Of the glycidyl-group containing copolymers consisting essentially of 
.alpha.-olefin and glycidyl ester of .alpha.,.beta.ethylenically 
unsaturated carboxylic acid, the former include ethylene, propylene, 
butene-1 and so forth, of which ethylene is preferable. The latter 
compound represented by the following general formula: 
##STR2## 
wherein R denotes a hydrogen atom, a lower alkyl group or a glycidyl-group 
substituted lower alkyl group. Glycidyl acrylate, glycidyl methacrylate, 
glycidyl ethacrylate and glycidyl itaconate are the examples. Thereof, 
glycidyl methacrylate is preferable. The copolymers advantageously have a 
glycidyl unit of .alpha.,.beta.-ethylenically unsaturated carboxylic acid 
content in the range from 0.5 to 40 percent, preferably from 1 to 30 
percent, more preferably from 2 to 20 percent by weight. If the contents 
are less than 0.2 percent or more than 40 percent, the copolymers do not 
satisfactorily increase in impact resistance or decrease in molding 
flowability respectively. Glycidyl esters of .alpha.,.beta.-ethylenically 
unsaturated carboxylic acid can be copolymerized by standard 
copolymerization or graft reaction. Further, less than 40 percent by 
weight of at least one unsaturated monomers such as: vinyl ethers; vinyl 
acetate, propione and other vinyl esters; methyl, ethyl, propyl and butyl 
and other esters of acrylic or methacrylic acid; acrylonitrile; styrene; 
and carbon monoxide may be copolymerized with the above copolymers. 
The MI (Melt Index) of glycidyl-group containing copolymer is in the range 
of between 0.1 and 100, preferably between 0.5 and 30, wherein the value 
of MI is measured at 190.degree. C. according to ASTM D-1238 and the unit 
is gr./10 min. If the MI is less than 0.1 gr/10 min. or more than 100 
gr/10 min. increase is small in impact resistance. 
Preferable among glycidyl-group containing copolymers are ethylene / 
glycidyl methacrylate, ethylene / vinyl acetate / glycidyl methacrylate, 
ethylene / carbon monoxide /glycidyl methacrylate, ethylene / glycidyl 
acrylate, and ethylene / glycidyl acrylate / vinyl acetate copolymers. 
Among them ethylene / glycidyl methacrylate copolymer is more preferable. 
The glycidyl-group containing copolymers according to the subject invention 
are present in an amount of from 1 to 80 parts by weight, preferably of 5 
to 50 parts by weight, per the total 100 parts by weight of aromatic 
polyester and aromatic polycarbonate. If the amount is less than 1 part or 
more than 80 parts, polyester compositions do not satisfactorily increase 
in impact resistance or aromatic polyesters deteriorate in mechanical 
properties. 
The compositions according to the subject invention further increase in 
impact resistance when containing the ethylene based copolymer being 
composed of ethylene and .alpha.-olefin having 3 to 10 carbon atoms and/or 
the diene copolymer being composed of ethylene, .alpha.-olefin having 3 to 
10 carbon atoms and unconjugated diene. 
The above-mentioned .alpha.-olefins include propylene, butene-1, pentene-1, 
3-methylpentene-1, octacene-1, decene-1 and so forth. Thereof, propylene 
and butene-1 are preferable and more than two usable in combination. 
The unconjugated dienes include various kinds of norbonene compounds, 
dicyclopentadiene compounds, tetrahydroindene compounds, 1,4-hexadiene and 
so forth. Preferable thereamong are 5-ethylidene-2-norbonene, 
dicyclopentadiene and 1,4-hexadiene. 
The molar ratios of ethylene to .alpha.-olefin in the ethylene based 
copolymers are in the range between 40/60 and 99/1, preferably between 
70/30 and 95/5, and in the diene copolymers the copolymerized ratios of 
.alpha.-olefin and unconjugated diene are in an amount of from 5 to 80 mol 
percent, preferably from 10 to 60 mol percent and from 0.1 to 20 mol 
percent, preferably from 0.5 to 10 mol percent, respectively. 
The ethylene based copolymer and / or the diene copolymers are present in 
an amount of from 1 to 50 parts by weight, preferably from 5 to 40 parts 
by weight, per the total 100 parts by weight of aromatic polyesters and 
aromatic polycarbonates. 
The compositions according to the subject invention can be increased in 
stiffness by further adding inorganic fillers. This addition generally 
causes the decrease in impact resistance. It is however small in the case 
of the compositions according to the subject invention. 
Among the inorganic fillers according to the subject invention, fibrous and 
granular ones as well as their mixtures can be mentioned. The fibrous ones 
include glass, silas glass, almina, silicon carbide, ceramic, asbestos, 
gypsum, metal (e.g. stainless steel) and other inorganic and carbon 
fibers. The granular ones, on the other hand, include wollastonite, 
sericite, kaolin, mica, clay, bentonite, asbestos, talc, alumina silicate 
and other silicates; metal oxides such as alumina as well as silica, 
magnesium oxide, zirconium oxide and titanium oxide; carbonates such as 
calcium carbonate and magnesium carbonate as well as dolomite; sulfates 
such as calcium sulfate and barium sulfate; glass beads; boron nitride; 
silicon carbide; sialon. They are permitted to be hollow (e.g. hollow 
glass fiber, glass microballoon, silas balloon, carbon balloon, etc.). 
Preferable thereamong are glass fibers, carbon fibers, metal fibers, 
potassium titanate whisker, glass flakes, glass beads, wollastonite, mica, 
talc, clay, titanium oxide, aluminum oxide, calcium carbonate and barium 
sulfate. Particularily thereamong glass fiber is more preferable. The 
inorganic fillers should preferably be treated with silane, titanate or 
another conventional coupling agent, and glass fibers with a conventional 
converging agent such as epoxy resin and vinyl acetate resin. 
The inorganic fillers are to be added at the ratios by weight of 3 to 100 
parts, preferably of 5 to 80 parts, per the total 100 parts by weight of 
aromatic polyesters and aromatic polycarbonates. 
The compositions according to the subject invention can be increased in 
impact resistance by adding the compounds for promoting the reaction 
between epoxy compounds and carboxylic acids. They include triphenyl 
amine, 2,4,6-tris(dimethylaminomethyl)phenol and other tertiary amines; 
triphenyl and trisodecyl phosphites and other phosphite esters; 
triphenylallylphosphonium bromide and other phosphonium compounds; 
triphenylphosphine and other tertiary phosphines; lithium, calcium and 
other metal stearates; sodium dodecylbenzenesulfonate and sodium 
3,5-dicarbomethoxybenzenesulfonate and other metal sulfonates; sodium 
lauryl sulfate and other organic sulfate salts, and so forth. Their 
addition should be made at the ratios of 0.001 to 5 parts by weight to 100 
parts by weight of aromatic polyesters. 
The compositions according to the subject invention permit the addition of 
such quantities as not obstructing its object of more than one being 
selected from fibrous and granular fillers and reinforcements, 
antioxidants, heat stabilizers, ultraviolet ray-absorbents, lubricants, 
mold releasing agents, colorants including dyes and pigments, flame 
retardants and flame redarding assistants, antistatic agents, 
crystallization promotors, and other additives as well as of the small 
quantities of one or more than two being selected out of thermoplastic 
resins, thermosetting resins and thermoplastic elastomers. 
The processes for producing the compositions according to the subject 
invention are not limited. However, preferable thereamong are to 
melt-extrude, by using an extruder, the dry-blendings of aromatic 
polyesters, aromatic polycarbonates, glycidyl group containing copolymers 
and, if necessary, other additives. 
The resin compositions of the subject invention can be molded according to 
conventional methods such as injection molding, extrusion molding, and 
molded articles therefrom show excellent properties.