Stock material or miscellaneous articles – Structurally defined web or sheet – Including components having same physical characteristic in...
Reexamination Certificate
2002-12-13
2004-12-07
Chen, Vivian (Department: 1773)
Stock material or miscellaneous articles
Structurally defined web or sheet
Including components having same physical characteristic in...
C428S343000, C428S323000, C428S480000, C428S483000, C428S910000, C525S437000, C525S444000, C525S448000, C528S293000, C528S294000, C528S295000
Reexamination Certificate
active
06828010
ABSTRACT:
TECHNICAL FIELD
The present invention relates to improvements in laminated polyester films, and more specifically to a laminated polyester film excellent in adhesiveness to various types of coating materials.
BACKGROUND OF THE INVENTION
Since a biaxially oriented polyester film has excellent properties in dimensional stability, mechanical characteristics, thermal resistance, transparency, electric characteristics, chemical resistance and the like, it has widely been used as a base film for various types of products, such as a magnetic recording material, a packaging material, an electric insulating material, various types of photographic materials, a graphic arts material and the like.
Ordinarily, since a surface of the biaxially oriented polyester film is highly oriented in terms of crystallinity, it has a drawback of poor adhesiveness to various types of paints and inks. To this end, various studies for imparting adhesiveness to a surface of a polyester film by means of various types of methods have so far been conducted.
Heretofore, as the methods for imparting the adhesiveness to the surface of the polyester film, various types of adhesiveness imparting processing which performs on a polyester film as abase film, for example, a surface activation method such as a corona discharge treatment, ultraviolet ray irradiation processing, plasma processing and the like to be performed on a surface, a surface etching method to be performed by using chemicals such as an acid, an alkali, an amine aqueous solution and the like, a method of providing various types of resins each having adhesiveness such as an acrylic resin, a polyester resin, a urethane resin, a polyolefin resin and the like on a surface of film as a primer layer and other methods have been studied.
Among these methods, as examples of providing a polyester resin as a primer layer, mentioned are JP-A-10-86303, JP-A-60-198240, JP-A-2000-25182, JP-A-1-237138 and the like.
JP-A-10-86303 discloses a constitution, comprising two types of polyester resins having different glass transition temperatures (Tg's) from each other and a cross-linking agent, in which adhesiveness to various types of paints or inks and that under high temperature and high humidity are simultaneously viable. However, this constitution was unable to simultaneously satisfy adhesiveness to various types of coating materials such as a UV-curable ink, an oxidative polymerization-type ink, a solvent-type ink, water-soluble or hydrophilic resins, for example, polyvinyl alcohol and the like; therefore, this constitution was insufficient.
Further, JP-A-60-198240 discloses that adhesiveness to a metal can be satisfied by polyester comprising from 65% by mol to 95% by mol of isophthalic acid as a copolymerization component. However, such a constitution was unable to simultaneously satisfy adhesiveness to various types of same coating materials as described above and anti-blocking properties of laminated layers were insufficient thereamong.
Furthermore, JP-A-2000-25182 discloses that a constitution comprising two types of polyester resins having different Tg's from each other, an aliphatic amide and/or an aliphatic bisamide has good adhesiveness to a hard coat layer. However, the constitution was unable to simultaneously satisfy adhesiveness to various types of same coating materials as described above and anti-blocking properties of coated surfaces were insufficient thereamong.
Still further, JP-A-1-237138 discloses that a laminate prepared by co-extruding two types of polyester resins satisfies a heat sealing property. However, the laminate was unable to simultaneously satisfy adhesiveness to various types of same coating materials as described above.
Namely, there was a problem in that the polyester films as described above were unable to simultaneously satisfy adhesiveness to inks, particularly, those of UV-curable type which generates shrinkage when cured, and water-soluble, hydrophilic resins such as polyvinyl alcohol and the like thereby being insufficient in many cases.
The subject of the present invention is to provide a laminated polyester film, which has improved such drawbacks as described above, satisfies adhesiveness to various types of coating materials which was incompatible conventionally, further, satisfies anti-blocking properties, transparency, scratch resistance and the like.
DISCLOSURE OF THE INVENTION
In order to solve the above-described subject, a laminated polyester film according to the present invention comprises being characterized in that a laminated layer comprising two types of polyester resins having different glass transition points from each other is formed on at least one side of a polyester film wherein the above-described two types of polyester comprises a polyester resin (A) having a glass transition point of from 60° C. to 100° C. and a polyester resin (B) having a glass transition point of from 0° C. to 60° C. and wherein the above-described polyester resin (B) at least contains from 65% by mole to 95% by mol of isophthalic acid as an acid component or from 50% by mol to 95% by mol of diethylene glycol as a diol component and, further, a dicarboxylic acid component having a sulfonic acid metal base in entire dicarboxylic acid components in the polyester resins (A) and (B) satisfies the following relation:
Sa>Sb≧5% by mol,
wherein
Sa represents a quantity (% by mol) of a dicarboxylic acid component having a sulfonic acid metal base in entire dicarboxylic acid components in the polyester resin (A); and
Sb represents a quantity (% by mol) of a dicarboxylic acid component having a sulfonic acid metal base in entire dicarboxylic acid components in the polyester resin (B).
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to preferred embodiments.
First of all, polyester film in a state before a laminated layer is formed thereon, in a laminated polyester film that is prepared by forming a laminated layer comprising two types of polyester resins having different glass transition points from each other on at least one side of polyester film according to the present invention, will be described.
In the polyester film according to the present invention, the term “polyester” is a generic name denoting a polymer in which ester bonding is allowed to be a primary bonding chain in a main chain thereof. As a preferred polyester, that having, as a principal constituent, at least one constituent selected from the group consisting of ethylene terephthalate, propylene terephthalare, ethylene-2,6-naphthalate, butylenes terephthalate, propylene-2,6-naphthalate, ethylene-&agr;,&bgr;-bis(2-chlorophenoxy)ethane-4,4′-dicarboxylate, ethylene-&agr;,&bgr;-bis(phenoxy)ethane-4,4′-dicarboxylate and the like can be used. These constituents may be used either individually or in any combinations thereof; however, it is preferable to use polyester in which ethylene terephthalate, among these constituents, is a principal constituent from an overall judgment taking quality, economy and the like into consideration. Further, such polyester may further be copolymerized with any other dicarboxylic acid component or diol component partially, preferably at a ratio of 20% by mol or less.
Further, a base polyester film in the laminated polyester film according to the present invention preferably further contains a polyester resin copolymerized with an isophthalic acid component or a diethylene glycol component as a principal constituent; the base polyester film in the laminated polyester film according to the present invention more preferably further contains a polyester resin copolymerized with the isophthalic acid component and the diethylene glycol component as a principal constituent. By taking such constitutions, adhesiveness between the laminated layer according to the present invention and the base polyester film is remarkably enhanced.
A quantity of the polyester resin, which is preferably further contained in the base polyester film, copolymerized with the isophth
Kubota Yuri
Mimura Takashi
Takada Yasushi
Yanagibashi Masato
Chen Vivian
Piper Rudnick LLP
Toray Industries Inc.
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