Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2002-08-15
2003-07-08
Nolan, Sandra M. (Department: 1772)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S444000
Reexamination Certificate
active
06590044
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an aromatic polyester composition comprising an ethylene naphthalenedicarboxylate copolymer and an ethylene terephthalate (co)polymer, molded products thereof and a bottle production process. More specifically, it relates to an aromatic polyester composition which is excellent in compatibility at the time of blending and transparency and which is hardly deteriorated by heat, molded products thereof and a bottle production process.
BACKGROUND ART
Polyethylene terephthalate and polyethylene naphthalenedicarboxylate polymers are mainly used for drink-related applications due to their excellent characteristic properties. However, polyethylene terephthalate, though excellent in terms of transparency, is slightly inferior in heat resistance. Therefore, it is desirable to improve the heat resistance of the polymer. Meanwhile, polyethylene naphthalenedicarboxylate, though having excellent properties such as transparency, heat resistance, ultraviolet screening properties and barrier properties, is more expensive than general-purpose resins. Therefore, it is difficult to grow the popularity of the polymer without a cost reduction. To overcome these defects of the polyesters, there are proposed polyethylene naphthalenedicarboxylate obtained by copolymerizing a terephthalic acid component, polyethylene terephthalate obtained by copolymerizing a naphthalenedicarboxylic acid component or a blend of a polyester whose main recurring unit is an ethylene terephthalate unit and a polyester whose main recurring unit is an ethylene naphthalenedicarboxylate unit.
Although a polyester obtained by copolymerizing a terephthalic acid component or naphthalenedicarboxylic acid component has the characteristic properties of the both components, when the amount of a copolymer component is increased, the polyester becomes almost amorphous and is inferior in handling properties. A blend of a polyester whose main recurring unit is an ethylene terephthalate unit and a polyester whose main recurring unit is an ethylene naphthalenedicarboxylate unit has excellent handling properties and has such an advantage that the blending ratio of these polyesters can be changed easily. However, a process for obtaining a polyester having high transparency must be under blending conditions, such as a high temperature and a long residence time, which are unfavorable for polyesters from the viewpoint of compatibility between them.
JP-A 11-43589 discloses a polyester resin composition comprising 99 to 60 wt % of a polyethylene terephthalate resin (A) and 1 to 40 wt % of a polyethylene naphthalate resin (B). In this composition, these resins have the following characteristic properties.
That is, the above polyethylene terephthalate resin (A) is characterized in that (1) the main recurring unit is ethylene terephthalate, (2) 85 mol % or more of terephthalic acid is contained as a dicarboxylic acid component and (3) 85 mol % or more of ethylene glycol and 1.0 to 5.0 mol % of diethylene glycol are contained as glycol components, (4) the total of the concentration of a terminal methyl ester group and the concentration of a terminal carboxyl group is 30 eq/10
6
g or less, and (5) the bulk density of the chip of the resin (A) is 0.83 to 0.97 g/cm
3
. Meanwhile, the above polyethylene naphthalate resin (B) is characterized in that (1) the main recurring unit is ethylene-2,6-naphthalenedicarboxylate, (2) 85 mol % or more of 2,6-naphthalenedicarboxylic acid is contained as a dicarboxylic acid component and (3) 85 mol % of ethylene glycol and 1.0 to 5.0 mol % of diethylene glycol are contained as glycol components, (4) the total of the concentration of a terminal methyl ester group and the concentration of a terminal carboxyl group is 30 eq/10
6
g or less, and (5) the bulk density of the chip of the resin (B) is 0.83 to 0.97 g/cm
3
.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide an aromatic polyester composition comprising an ethylene naphthalenedicarboxylate copolymer and an ethylene terephthalate (co) polymer.
It is another object of the present invention to provide an aromatic polyester composition having excellent compatibility, transparency, heat resistance and gas barrier properties.
It is still another object of the present invention to provide molded products such as a bottle which are formed of the above aromatic polyester composition of the present invention and have excellent properties.
It is a further object of the present invention to provide a process for producing a bottle having excellent properties without impairing the excellent properties of the above aromatic polyester composition of the present invention.
Other objects and advantages of the present invention will become apparent from the following description.
According to the present invention, firstly, the above objects and advantages of the present invention are attained by an aromatic polyester composition comprising:
(A) (a) an ethylene naphthalenedicarboxylate copolymer which contains an ethylene naphthalenedicarboxylate unit in an amount of 94 to 80 molt based on the total of all the recurring units and an ethylene terephthalate units and/or an ethylene isophthalate unit in an amount of 6 to 20 mol % based on the total of all the recurring units and a diethylene glycol unit in an amount of 0.8 to 2.5 wt % and has a number of terminal carboxyl groups of 40 eq/10
6
g or less and a total number of terminal groups of 95 eq/10
6
g or more, and (b) an ethylene terephthalate 10 (co)polymer which contains an ethylene terephthalate unit in an amount of 100 to 80 mol % based on the total of all the recurring units and an ethylene naphthalenedicarboxylate unit and/or an ethylene isophthalate unit in an amount of 0 to 20 mol % based on the total of all the recurring units and a diethylene glycol unit in an amount of 1.2 to 2.4 wt % and which has a number of terminal carboxyl groups of 30 eq/10
6
g or less, an intrinsic viscosity of 0.7 or more and a melting temperature of 250° C. or less, the contents of the ethylene naphthalenedicarboxylate copolymer and the ethylene terephthalate (co)polymer being 5 to 95 wt % and 95 to 5 wt % based on the total weight of these, respectively;
(B) compatibility between the ethylene naphthalenedicarboxylate copolymer and the ethylene terephthalate (co)polymer being 0.15 to 0.5; and
(C) the relationship represented by the following expression (1) being satisfied when the proportion of the ethylene naphthalenedicarboxylate unit to the total of all the recurring units of the ethylene naphthalenedicarboxylate copolymer and all the recurring units of the ethylene terephthalate (co)polymer is 50 mol % or less:
Tm
≦254−28
×EN
(1)
wherein EN is the molar fraction of the ethylene naphthalenedicarboxylate unit in the polyester composition and Tm is the melting point (° C.) of the polyester composition,
and the relationship represented by the following expression (2) being satisfied when the proportion of the ethylene naphthalenedicarboxylate unit to the total of all the recurring units of the ethylene naphthalenedicarboxylate copolymer and all the recurring units of the ethylene terephthalate (co)polymer is more than 50 mol %:
Tm
≦267−54
×EN
(2)
wherein Tm and EN are the same as defined in the above expression (1).
According to the present invention, secondly, the above objects and advantages of the present invention are attained by molded products, such as a bottle, of the above aromatic polyester composition of the present invention.
According to the present invention, thirdly, the above objects and advantages of the present invention are attained by a bottle production process comprising the steps of:
melt-kneading the ethylene naphthalenedicarboxylate copolymer (a) and the ethylene terephthalate (co)polymer (b) specified by the above aromatic polyester composition in amounts of 5 to 95 wt % and 95 to 5 wt % based on the total weight of these, respectively, under injection molding conditions comprising a m
Nagano Hiroki
Suzuki Minoru
Yoshida Yoichi
Nolan Sandra M.
Teijin Limited
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