Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2001-01-03
2003-02-25
Cain, Edward J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S272000, C528S287000, C528S293000, C528S294000, C528S295000
Reexamination Certificate
active
06525165
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a film of a trimethylene-2,6-naphthalene dicarboxylate (co)polymer comprising a 2,6-naphthalene dicarboxylic acid component and a 1,3-propanediol component, a sulfonic acid quaternary phosphonium salt copolymer and a composition thereof.
PRIOR ART
Polyethylene terephthalate (may be abbreviated as PET hereinafter) is widely used as molded products such as films exemplified by magnetic recording tapes, capacitors, ink ribbons and thermally shrinkable labels for PET bottles, sheets exemplified by trays, hollow containers and cover materials thereof, and PET bottles thanks to its excellent mechanical and chemical properties as a material.
However, PET is not satisfactory yet in terms of gas barrier properties against oxygen and carbon dioxide though it is superior to polyethylene and polypropylene. The further improvement of gas barrier properties of PET is desired when it is used to wrap contents which are easily oxidized, such as food containing oil, and when it must prevent the leakage of filled gas like carbonated drinks.
To improve the gas barrier properties of PET, there are known methods of coating or laminating a resin having higher gas barrier properties than PET, such as polyvinylidene chloride, ethylene-vinyl acetate copolymer saponified product or polyamide. These resins have poor adhesion to PET, thereby causing delamination, whereby a container loses its transparency, and a laminate consisting of different types of polymers is disadvantageous from the viewpoint of recovery.
There are proposed a method of using a polymer obtained by substituting part or all of the terephthalic acid component of PET with isophthalic acid in place of PET (JP-A 59-64624) (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) and a method of improving gas barrier properties by copolymerizing 1,3-phenylene dioxydiacetic acid or the like (JP-A 60-501060). Both methods involve such problems that satisfactory gas barrier properties are not achieved, a reduction in glass transition temperature (Tg) is large and heat resistance deteriorates.
An ethylene-vinyl acetate copolymer (to be abbreviated as EVOH hereinafter), polyamides (to be abbreviated as PA hereinafter) and polyvinylidene chloride (to be abbreviated as PVDC hereinafter) are used as polymers having higher gas barrier properties than the above polyester. However, the gas barrier properties of EVOH and PA greatly depend upon humidity and deteriorate at a high humidity. PVDC may generate a poisonous gas such as dioxin when it is burnt.
PET films and PA films are widely used for packing as a film having high piercing strength and high piercing resistance. However, as these films have high tear strength, when they are used in a wrapping bag and their contents are to be taken out from the wrapping bag, the bag cannot be easily ripped open and it takes time to take out the contents.
To provide tearability to a film, the end of the film is notched or slit, or an uniaxially stretched film of a polyamide or polyolefin is used as an inner layer and laminated with a polyester to produce a film. These methods boost costs, disadvantageously. It is desired that a film itself should have tearability if possible.
Thus, a film which is easily torn while it has high piercing strength is unknown. If a film having both piercing resistance and tearability is obtained, it is expected to be used in a wide range of fields including packing materials.
Poly(methylene-2,6-naphthalene dicarboxylate) itself is disclosed by JP-B 43-19108 (the term “JP-B” as used herein means an “examined Japanese patent publication”) which discloses a composite filament or composite staple fiber and the other polyester thereof which is produced in the presence of a polymer comprising trimethylene dinaphthalate as a polymerization unit, that is, a mixture of poly(trimethylene dinaphthalate), poly(trimethylene-2,6-dinaphthalate)Mn(OAc)
2
and Ti(OBu)
4
as a catalyst and which has a relative viscosity of 0.67.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a film of an aromatic polyester which is superior in gas barrier properties to PET out of polyesters having excellent features that they have small humidity dependence and that they do not generate a poisonous gas when they are burnt.
It is another object of the present invention to provide an aromatic polyester film which is easily torn while it has high piercing strength.
It is still another object of the present invention to provide a film having excellent features which has gas barrier properties equivalent to those of a polyamide film, does not experience an increase in moisture permeability unlike a polyamide film and a reduction in gas barrier properties at a high humidity and does not generate a poisonous gas when it is burnt.
It is a further object of the present invention to provide an aromatic polyester which has excellent adhesion to a rotary cooling drum, and excellent productivity and sanitation because it suppresses the contamination of an electrostatic wire and the adhesion of a sublimate to an extrusion nozzle in the production of a film.
It is a still further object of the present invention to provide an aromatic polyester which decreases the amount of a component eluting from a polyester film without reducing the production efficiency of a film in the production of the film and is suitable for use in packages, especially food packages.
It is a still further object of the present invention to provide an aromatic polyester which can decrease the amount of an oligomer eluting from a polyester film without reducing the production efficiency of a film in the production of the film.
It is a still further object of the present invention to provide an aromatic polyester which has a small content of foreign matter and is excellent in color, moldability, light resistance and gas barrier properties in the production of a film.
It is a still further object of the present invention to provide an aromatic polyester which gives a film having excellent antifungal properties.
It is a still further object of the present invention to provide a laminated polyester film having a primer layer which is excellent in gas barrier properties, heat resistance, water resistance, anti-block properties and adhesion.
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 film, (1) which comprises an aromatic polyester comprising 2,6-naphthalenedicarboxylic acid as the main dicarboxylic acid component and 1,3-propanediol as the main diol component and (2) having a density of at least 1.310 g/cm
3
.
Secondly, the above objects and advantages of the present invention are attained by a laminated polyester film comprising the above aromatic polyester film of the present invention and another polyester layer existent on at least one side of the film.
Thirdly, the above objects and advantages of the present invention are attained by an aromatic polyester which comprises 2,6-naphthalenedicarboxylic acid as the main dicarboxylic acid component and 1,3-propanediol as the main diol component and a sulfonic acid quaternary phosphonium salt having an ester forming functional group in an amount of 0.1 to 45 mmol % based on the total of all the dicarboxylic acid components.
In the fourth place, the above objects and advantages of the present invention are attained by a polyester composition which comprises the above aromatic polyester of the present invention in an amount of 60 wt % or more and another aromatic polyester in an amount of 40 wt % or less based on the total of the aromatic polyester and the another aromatic polyester.
In the fifth place, the above objects and advantages of the present invention are attained by an antifungal polyester composition which comprises any one of the aromatic polyester of the present invention and the above
Furuya Koji
Handa Makoto
Kawai Shinichi
Kosuge Masahiko
Kudo Takafumi
Cain Edward J.
Sughrue & Mion, PLLC
Teijin Limited
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