Note: Descriptions are shown in the official language in which they were submitted.
CA 02028673 1997-12-23
1
THERMOPLASTIC RESIN COMPOSITION
The present invention relates to a thermoplastic
resin composition which yields a molded article having
improved balance among heat resistance, chemical resistance,
impact resistance and a shrinkage factor; falling ball impact
resistance; weld strength; and appearance.
Polycarbonate resins have good heat resistance and
impact strength and are used in many technical fields, such as
vehicles. However the polycarbonate resins possess
unsatisfactory chemical resistance and depend largely on
thickness of the molded article for impact strength.
To improve the chemical resistance of the poly-
carbonate resin, it has been proposed to blend the poly-
carbonate resin with a saturated polyester, e.g. polybutylene
terephthalate. However, such a blend deteriorates impact
strength, which is one of the characteristics of the
polycarbonate resin and also has an unsatisfactory shrinkage
factor. In addition, the blend cannot improve the dependency
of impact strength on the thickness.
Recently, various ternary resin compositions
comprising a polycarbonate resin, a saturated polyester and a
rubber or a copolymer have been made. However, the ternary
compositions do not have good balance among heat resistance,
chemical resistance, impact strength and a shrinkage factor.
In addition, since the ternary compositions comprises plural
components, a molded article of the compositions has poor
falling ball impact strength and weld strength.
A
CA 02028673 2001-02-16
2
An object of the present invention is to provide a
thermoplastic resin composition comprising a polycarbonate
resin, a saturated polyester and a specific copolymer from
which an article having improved balance among heat
resistance, chemical resistance, impact resistance and a
shrinkage factor; falling ball impact resistance; weld
strength; and appearance can be molded.
According to the present invention, there is
provided a thermoplastic resin composition comprising
1 to 300 parts by weight of a copolymer (A) which is
obtained by polymerizing 0.1 to 400 parts by weight of an
unsaturated epoxy monomer and 0 to 1,000 parts by weight of
other copolymerizable monomers in the presence of 100 parts by
weight of an ethylene-a-olefin base rubber, and
100 parts by weight of a mixture comprising 90 to
10 % by weight of a polycarbonate resin (B) and 10 to 90 % by
weight of a saturated polyester (C).
The thermoplastic resin composition of the present
invention will be illustrated in detail.
' CA 02028673 1997-12-23
- 3 -
The ethylene-a-olefin base rubber constituting the
copolymer (A) includes a copolymer of ethylene with propy-
lene or butene (EPR), a terpolymer of ethylene, propylene or
butene and a non-conjugated diene (EPDM) and the like.
These may be used independently or as a mixture thereof.
Examples of the non-conjugated dime contained in
the terpolymer (EPDM) are dicyclopentadiene, ethylidene-
norbornene, 1,4-hexadiene, 1,4-cyclobutadiene, 1,5-cyclo-
octadiene and the like.
In the copolymer (EPR) and the terpolymer (EPDM),
a molar ratio of ethylene to propylene or butene is prefe-
rably from 5:l to 1:3.
In the terpolymer (EPDM), the non-conjugated diene
is contained in an amount corresponding to an iodine value
of 2 to 50.
The unsaturated epoxy monomer constituting the
copolymer (A) includes an unsaturated glycidyl ester of the
formula:
0 O
II / \ ( I 1
R-C-0-CH2-CH-CH2
wherein R is a hydrocarbon group having a copolymerizable
epoxide unsaturated bond, an unsaturated glycidyl ether of
the formula:
0
/ \ (II)
R-X-CH 2-CH-CH 2
CA 02028673 1997-12-23
- 4 -
wherein R is the same as defined in the formula (I), and X
is -CH2-O- or -( p r0-, and an epoxyalkene of the formula:
R'
R-C CH2 (III)
0'
wherein R is the same as defined in the formula (I), and R'
is hydrogen or methyl.
Specific examples of these epoxide monomers are
glycidyl acrylate, glycidyl methacrylate, mono- and di-
glycidyl ester of itaconic acid, mono-, di- and tri-glycidyl
ester of butenetricarboxylic acid, mono- and di-glycidyl
ester of citraconic acid, mono- and di-glycidyl ester of
endo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid
(trade -mark.: Nadic acid), mono- and di-glycidyl ester of
endo-cis-bicyclo[2.2.1]hept-5-ene-2-methyl-2,3-dicarboxylic
acid (trade-park Methylnadic acid), mono- and di-glycidyl
ester of allylsuccinic acid, glycidyl ester of p-styrene-
carboxylic acid, allylglycidyl ether, 2-methylallylglycidyl
ether, styrene-p-glycidyl ether or p-glycidylstyrene, 3,4-
epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, 3,4-epoxy-1-
pentene, 3,4-epoxy-3-methyl-1-pentene, 5,6-epoxy-1-hexene,
vinylcyclohexene monoxide, and the like.
Other copolymerizable monomersconstituting the
copolymer (A) include
(i) aromatic vinyl compounds (e.g. styrene, a-
methylstyrene, a-chlorostyrene, p-tert.-butylstyrene, p-
;.
r n
CA 02028673 1997-12-23
- 5 -
methylstyrene, o-chlorostyrene, p-chlorostyrene, 2,5-di-
chlorostyrene, 3,4-dichlorostyrene, p-bromostyrene, o-bromo-
styrene, 2,5-dibromostyrene, 3,4-dibromostyrene, cyano-
styrene, 2-isopropenylnaphthalene, etc.),
(ii) cyanated vinyl compounds (e. g. acrylonitrile,
methacrylonitrile, maleonitrile, fumaronitrile, etc.),
(iii) alkyl unsaturated carboxylates (e. g. methyl
acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,
methyl methacrylate, ethyl methacrylate, butyl methacrylate,
hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxy-
propyl methacrylate. etc.),
(iv) unsaturated carboxylic acids (e. g. acrylic
acid, methacrylic acid, etc.),
(v) unsaturated dicarboxylic anhydrides (e. g.
malefic anhydride, itaconic anhydride, citraconic anhydride,
aconitic anhydride, hymic anhydride, etc.),
(vi) maleimide compounds (e.g. maleimide, N-
methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-
laurylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide,
N-o-chlorophenylmaleimide, etc.). One or more of them can
be used. Among them, at least one compound selected from
the group consisting of the aromatic vinyl compounds (i),
the cyanated vinyl compounds (ii) and the alkyl unsaturated
carboxylates (iii) is preferred.
The copolymer (A) is prepared by copolymerizing
0.1 to 400 parts by weight of the unsaturated epoxy monomer
CA 02028673 1997-12-23
'"'' 6
and 0 to 1,000 parts by weight of other copolymerizable
monomers in the presence of 100 parts by weight of the
ethylene-a-olefin base rubber.
When the amount of the unsaturated epoxy monomer is
outside the range of 0.1 to 400 parts by weight, the impact
strength and weld strength of the molded article are not
improved.
When the amount of other copolymerizable monomers
exceed 1,000 parts by weight, neither the impact strength nor
the weld strength of the molded article is improved.
In view of the impact strength and weld strength of
the molded article, preferably 0.2 to 300 parts by weight of
the unsaturated epoxy monomer and 10 to 500 parts by weight of
other copolymerizable monomer are used per 100 parts by weight
of the ethylene-a-olefin base rubber.
As the polycarbonate resin (B), aromatic
polycarbonates, aliphatic polycarbonates, aliphatic-aromatic
polycarbonates and the like are exemplified.
Generally, the polycarbonate resin (B) is a polymer
or a copolymer prepared from a bisphenol type compound such as
2,2-bis(4-oxyphenyl)alkanes, bis(4-oxyphenyl)ethers and bis(4-
oxyphenyl)sulfones, sulfides or sulfoxides. For some end
uses, polymers of halogen-substituted bisphenol type compounds
may be used.
Preparation methods and kinds of polycarbonate
resins are described, for example, in "Polycarbonate Resins"
A
CA 02028673 2001-02-16
_ 7 _
published by Daily Technology Newspaper Company (Nikkan
Kogyo Shinbun-sha) (September 30, 1969).
The saturated polyester (c) is a polyester
which is obtainable by polymerizing an acid component
S comprising a dicarboxylic acid or its ester-forming
derivative and a low molecular weight glycol having 2
to 10 carbon atoms or its ester-forming derivative. As
an additional acid component, a small amount of at
least one of aliphatic dicarboxylic acids having 2 to
32 carbon atoms, alicyclic dicarboxylic acids and their
ester-forming derivatives may be used.
Specific examples of the low molecular weight
glycols having 2 to 10 carbon atoms are ethylene
glycol, propylene glycol, tetramethylene glycol,
pentamethylene glycol, hexamethylene glycol,
decamethylene glycol, cyclohexane dimethanol, neopentyl
glycol, diethylene glycol, 2,2-bis(4-hydroxyphenyl)
propane, p-xylilene glycol and the like. They may be
used independently or as a mixture.
CA 02028673 1997-12-23
r
Specific examples of the aliphatic dicarboxylic
acid having 2 to 32 carbon atoms are adipic acid, sebacic
acid, azelaic acid, dodecane dicarboxylic acid, cyclohexane
dicarboxylic acid, dimeric acid and their lower alkyl
esters, cycloalkyl esters, aryl esters, hydroxyalkyl esters
and acid halides. They may be used independently or as a
mixture.
Preferred examples of the saturated polyester (C)
are polyethylene terephthalate, polytetrametylene terephtha-
late, polybutylene terephthalate and the like. The may be
used independently or as a mixture.
The saturated polyester (C) may be prepared by a
conventional method.
The thermoplastic resin composition of the present
invention comprises 1 to 300 parts by weight of the copoly-
mer (A) and 100 parts by weight of a mixture comprising 90
to 10 % by weight of the polycarbonate resin (B) and 10 to
90 % by weight of the saturated polyester (C).
When the amount of the copolymer (A) is less than
1 part by weight, the molded article has poor impact resis-
tance. When the amount of the copolymer (A) exceeds 300
parts by weight, the molded article is poor in heat resis-
tance, impact resistance, falling ball impact resistance and
weld strength. In view of the balance among the physica l
Properties, the copolymer (A) is used in an amount of 5 to
200 parts by weight per 100 parts of the mixture of the
polycarbonate (B) and the saturated polyester (C).
.:
CA 02028673 2001-02-16
- 9 -
When the amount of the polycarbonate resin (H)
exceeds 90 % by weight in the mixture of the polycarbonate
(H) and the saturated polyester (C), the molded article has
poor chemical resistance. When it is less than 10 % by
weight, the molded article has poor heat resistance and a
large shrinkage factor. In view of chemical resistance,
heat resistance and the shrinkage factor of the molded
article, the weight ratio of the polycarbonate (B) to the
saturated polyester (C) is from 80:20 to 20:80.
As mixing means, any of conventional mixing appa-
ratuses such as a Banbury'"" mixer, a single screw extruder and
a twin screw extruder may be used. There is no limitation on
tn:e sequence of mixing the copolymer (A), the polycarbonate
resin (B) and the saturated polyester (C): For example, all
the three components are simultaneously mixed, or two of the
components are premixed and them mixed with the other one.
If desired, the thermoplastic resin composition of
the present invention may contain a dye, a pigment, an anti
oxidant, a.plasticizer, an antistatic agent, an ultraviolet
light absorbing agent, a lubricant, a filler, a flame retar-
dant and the like. In addition, the composition of the
present invention may contain other thermoplastic resins
such as AHS resins, MBS resins, AHSM resins, AAS resins, ACS
resins, polyvinyl chloride, ethylene-vinyl chloride copoly-
mers, chlorinated polyethylene, ethylene-vinyl acetate
copolymers, styrene-malefic anhydride copolymers, stylene-
CA 02028673 1997-12-23
- lU -
acrylonitrile-malefic anhydride copolymers, styrene-maleimide
copolymers, styrene-acrylonitrile-maleimide copolymers,
polyester elastomers, polyamide, polyacetal, polysulfone and
the like.
The present invention will be illustrated by the
following examples, which will not limit the scope of the
present invention.
Examples rl-6 and Comparati-v~e Examples ~1-6
A copolymer (A), a polycarbonate resin (H) and a
'saturated polyester were compounded in a ratio shown in
Tables 1, 2 and 3 with a twin screw extruder to prepare each
resin composition. Each composition was injection molded to
produce a sample piece for measuring physical properties.
The results are also shown in Tables 1, 2 and 3.
I5 (1) Copolymer (A-1)
This copolymer was prepared by dissolving 100
parts by weight of EPDM having an iodine value of 8.5, a
Mooney viscosity of 61 and a propylene content of 43 % by
weight and containing ethylidenenorbornene as a diene com-
ponent in 1200 parts by weight of n-hexane and 800 parts by
weight of ethylene dichloride, adding 20 parts by weight of
glycidyl methacrylate and 0.4 part by weight of benzoyl
peroxide and then effecting polymerization at 67°C for 10
hours in a nitrogen atmosphere. The polymerization liquid
was contacted with a large excess amount of methanol to
A
CA 02028673 1997-12-23
''"~ 11
precipitate the product, which was separated and dried to
yield the copolymer.
(2) Copolymer (A-2)
The copolymer was prepared in the same manner as in
(1), by dissolving 100 parts by weight of EPDM having an
iodine value of 15.3, a Mooney viscosity of 67 and a propylene
content of 50 % by weight and containing ethylidenenorbornene
as a diene component in 1250 parts by weight of n-hexane and
850 parts by weight of ethylene dichloride and adding 15 parts
by weight of glycidyl methacrylate, 35 parts by weight of
acrylonitrile, 100 parts by weight of styrene and 3 parts by
weight of benzoyl peroxide.
(3) Copolymer (A-3)
The copolymer was prepared in the same manner as in
(2), by using glycidyl methacrylate, acrylonitrile, styrene
and benzoyl peroxide in an amount of 8, 100, 250 and 8 parts
by weight, respectively.
(4) Copolymer (a-1)
A copolymer as prepared in (1), with addition of
EPDM in the preparation.
(5) Copolymer (a-2)
A polymer prepared by the same manner as (2) but
using no glycidyl methacrylate.
(6j Polycarbonate resin (B)
A polycarbonate resin having a molecular weight of
about 25,000 and comprising repeating units of the formula:
a
CA 02028673 1997-12-23
.",.
- 12 -
CH3
O-~-C~-O-C
II
CH3 O n
(7) Saturated polyester (c-1)
Polybutylene terephthalate
(8) Saturated polyester (c-2)
Polyethylene terephthalate.
Table 1
Example Com. Com. 1 2 Com.
No. 1 2 3
Composition (wt. parts)
(A) Copolymer
A-1 10 10
A-2 10
A-3
a-1
a-2 . 10
(B) Polycarbonate resin 50 5 30 50 50
(C) Saturated polyester
C-1 (PHT) 50 95 70 50 50
C-2 (PET)
Physical properties
Heat resistance (C) 102 64 87 100 100
Chemical resistance 0 O O O O
Impact resistance 8 14 60 ~ 74 55
(kg.cm/cm)
Molding shrinkage factor 0.7 2.1 1.1 0.7 0.7
( o)
Falling ball impact >600 >600 >600 >600 >600
strength (kg/cm)
Weld strength (kg.cm) 120 150 220 300 60
CA 02028673 1997-12-23
- 13 -
Table 2
Example 3 Com. 4 Com. 5
No. 4 5
Composition (wt. parts)
(A) Copolymer
A-1 30
A-2 10 10
A-3 10
a-1 30
a-2
(B) Polycarbonate resin 50 50 70 95 70
(C) Saturated polyester
C-1 (PBT) 50 50 30 5 30
C-2 (PET)
Physical properties
Heat resistance (C) 86 76 111 123 106
Chemical resistance 0 0 O X 0
Impact resistance 78 6 77 64 37
(kg.cm/cm)
Molding shrinkage factor 0.9 1.4 0.6 0.5 0.7
(%)
Falling ball impact >600 <100 >600 >600 500
strength (kg/cm)
Weld strength (kg.cm) 270 <10 240 210 150
CA 02028673 1997-12-23
- 14 -
Table 3
Example 6 7 Com.
No. 6
Composition (wt. parts)
(A) Copolymer
A-1
A-2
A-3 40 40 200
a-1
a-2
(B) Polycarbonate resin 30 50 50
(C) Saturated polyester
C-1 (PBT) 50 50 50
C-2 (PET) 20
~ 4
Physical properties
~
Heat resistance (C) 91 101 92
Chemical resistance 0 0 X
Impact resistance 67 77 12
(kg.cm/cm)
Molding shrinkage factor 0.6 0.5 0.5
Falling ball impact >600 >600 150
strength (kg/cm)
Weld strength (kg.cm) 240 300 <10
The physical properties are measured as follows:
Heat resistance
According to ASTM D-648
1/4 inch, 264 psi, no anneal
Impact Strenc,
According to ASTM D-256
1/4 inch, 23°C.
Molding shrinkage factor
Calculated from a difference between a size of the
ASTM No. 1 dumbbell mold and a size of a molded dumbbell
piece.
A
_ CA 02028673 1997-12-23
- 15 -
Weld strength
A resin melt (270°C) was injected from two gates
(each 4.0 x 2.5 mm) with a distance of 40 mm to form a test
piece of 3 mm in thickness, 60 mm in length and 60 mm in
width.
The test piece was placed on a jig having a height
of 80 mm, an inner diameter of 45 mm and an outer diameter
of 50 mm.
In a low temperature room kept at -30°C, a steel
ball of l kg was fallen onto a center of the test piece from
a height of 10 to 120 cm (every 10 cm, using five test
pieces at each height) and the maximum energy (kg.cm) with
which all five test pieces were not broken was recorded.
Falling ball impact strength
The same setup used in the measurement of weld
strength was used. A test piece was molded with one gate,
and the maximum energy (kg.cm) was measured in the same
manner as in the measurement of weld strength except that a
steel ball of 5 kg was used.
Chemical resistance
Flexural stress was applied on a 1/8 inch test
peace according to ASTM D-648 and a wax cleaner (MC-21 manu-
factured by BEL-RAY). After 48 hours, the presence of brea-
kage was observed. In Tables, "O" indicates "no breakage"
and "X" indicates "breakage"
* Trade-Mark
A
