Stock material or miscellaneous articles – Composite – Of addition polymer from unsaturated monomers
Reexamination Certificate
2001-12-28
2004-03-23
Nakarani, D. S. (Department: 1773)
Stock material or miscellaneous articles
Composite
Of addition polymer from unsaturated monomers
C428S520000, C428S522000, C428S910000, C525S191000, C525S216000, C525S221000, C525S240000, C525S241000
Reexamination Certificate
active
06709761
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a molded article and s composition comprising as the main components an ionomer (A) and a resin (B) having an alicyclic structure in its molecule.
TECHNICAL BACKGROUND
Metal salts of &agr;-olefin-unsaturated carboxylic acid copolymers are excellent in transparency, heat sealing, adhesion, pinhole resistance, elasticity and toughness, etc. and have been widely used in various fields for food packaging, daily necessities, industrial materials, etc. However, these metal salts of &agr;-olefin-unsaturated carboxylic acid copolymers are inferior in view of rigidity, heat resistance or moisture barrier characteristics, and involved problems with resistance to acids or alkalis.
On the other hand, a resin containing an aliphatic structure in its molecule, including a cyclic olefin-based polymer, provides excellent transparency, heat resistance, rigidity and moisture barrier characteristics but is inferior in toughness, adhesion or elasticity. Thus, it has been desired to solve these problems.
A film made of the metal salt of &agr;-olefin-unsaturated carboxylic acid copolymer is suitable for use of a heat shrinkable film because of excellent heat shrinkage but due to relatively large after-shrinkage (natural shrinkage) during storage of films and failure of adhesion with a solvent, which leads to difficulty in manufacturing a cylindrical product from a flat film, its applications are limited in some occasions.
Turning to heat shrinkable films, materials such as polyethylene, polypropylene, nylon, polyvinylidene chloride, vinyl chloride, polystyrene, polyethylene terephthalate, etc. have been used for preparing these films. However, a heat shrinkable film made of crystalline resins such as ethylene, polypropylene, nylon, etc. has a problem of large natural shrinkage. Whereas a heat shrinkable film of non-crystalline or substantially non-crystalline resin such as polyvinylidene chloride, vinyl chloride, polystyrene or polyethylene terephthalate has an advantage of a relatively small natural shrinkag, but due to its high density, involves problems that waste disposal costs increase and such a recycling process of separating a heat shrinkable film from a packaged material with water is not usable.
Furthermore, materials such as vinylidene chloride or vinyl chloride, etc. are concerned with generation of noxious gas during burning and polystyrene is suspected to be an environmental hormone.
Therefore, it has been desired to develop a heat shrinkable film that satisfies all requirements for a low natural shrinkage percentage, a high heat shrinkage percentage, a low density and hygiene.
DISCLOSURE OF THE INVENTION
The present invention provides an excellent molded article in view of impact property, adhesion property and printability.
The present invention provides a molded article, especially a heat shrinkable film, which has a low natural shrinkage percentage, a high shrinkage percentage upon heating and a low density and is excellent in a solvent resistance and hygiene.
The present invention provides a molded article comprising as the main components the ionomer (A), which is a metal salt of a copolymer containing an &agr;-olefin unit and an unsaturated carboxylic acid unit, and the resin (B) having an alicyclic structure in its molecule.
The present invention provides a molded article formed of a composition comprising 1 to 99 wt % of the ionomer (A), which is a metal salt of a copolymer containing an &agr;-olefin unit and an unsaturated carboxylic acid unit, and 99 to 1 wt % of the resin (B) having an alicyclic structure in its molecule.
The present invention provides a molded article that is a laminate comprising at least one layer containing the ionomer (A), which is a metal salt of a copolymer containing an &agr;-olefin unit and an unsaturated carboxylic acid unit, having laminated thereon at least one layer containing the resin (B) having an alicyclic structure in its molecule.
The present invention provides a sheet or film as a preferred molded article. Preferred embodiments of the molded article include a stretched film and a heat shrinkable film.
The present invention enables to provide a heat shrinkable film having a low natural shrinkage percentage, a high shrinkage percentage upon heating and a low density, and having excellent solvent resistance and hygiene.
The present invention provides a composition comprising 1 to 99 wt % of the ionomer (A) and 99 to 1 wt % of the resin (B) having an alicyclic structure in its molecule, which enables to prepare an excellent molded article in view of impact property, adhesion property and printability as well as a heat shrinkable film having a low natural shrinkage percentage, a high shrinkage percentage upon heating and a low density, and having excellent solvent resistance and hygiene.
SPECIFIC EMBODIMENTS FOR CARRYING OUT THE INVENTION
Hereinafter the present invention is described more specifically.
According to the present invention, there is provided a molded article comprising as the main components the ionomer (A), which is a metal salt of a copolymer containing an &agr;-olefin unit and an unsaturated carboxylic acid unit, and the resin (B) having an alicyclic structure in its molecule.
One preferred embodiment of the molded article according to the present invention is a molded article formed of a composition comprising 1 to 99 wt % of the ionomer (A), which is a metal salt of a copolymer containing an &agr;-olefin unit and an unsaturated carboxylic acid unit, and 99 to 1 wt % of the resin (B) having an alicyclic structure in its molecule.
Another preferred embodiment of the molded article according to the present invention is the laminate comprising at least one layer containing the ionomer (A), which is a metal salt of a copolymer containing an &agr;-olefin unit and an unsaturated carboxylic acid unit, having laminated thereon at least one layer containing the resin (B) having an alicyclic structure in its molecule.
According to the present invention, there is provided a composition comprising 1 to 99 wt % of the ionomer (A) and 99 to 1 wt % of the resin (B) having an alicyclic structure in its molecule, which enables to prepare an excellent molded article of the present invention.
These constituents are explained below in more detail.
Ionomer (A)
The ionomer (A) of the present invention is a metal salt of a copolymer containing an &agr;-olefin unit and an unsaturated carboxylic acid unit. Examples of the &agr;-olefin include an &agr;-olefin having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, etc. Among them, preferred examples of the &agr;-olefin are those having 2 to 4 carbon atoms such as ethylene, propylene, 1-butene, etc., with ethylene being more preferred.
Examples of the unsaturated carboxylic acid include an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, endo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxilic acid, etc. In addition, the unsaturated carboxylic acid may be in the form of its anhydride, more specifically, maleic anhydride, citraconic anhydride, etc. In these unsaturated carboxylic acids, preferred examples are acrylic acid and methacrylic acid.
As the copolymer containing an &agr;-olefin unit and an unsaturated carboxylic acid unit according to the present invention, a copolymer obtained by copolymerizing the &agr;-olefin and the unsaturated carboxylic acid described above is preferably employed. In this case, a content of the unsaturated carboxylic acid in the copolymer is generally from 1 to 50 wt %, preferably 1 to 20 wt %.
The copolymer containing an &agr;-olefin unit and an unsaturated carboxylic acid unit according to the present invention may further contain other monomer units, in addition to the &agr;-olefin unit and the unsaturated carboxylic acid. An example of the monomer units that can
Hirose Toshiyuki
Maeno Masao
Burns Doane , Swecker, Mathis LLP
Mitsui Chemicals Inc.
Nakarani D. S.
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