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AssigneeKureha Chemical Industry Co., Ltd.
InventorsHideaki Tanaka, Hiroyuki Ohba, Tomoaki Sato, Tomohisa Hasegawa
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The present invention provides a container for retort packaging comprising a laminated film having an outermost layer comprising a layer formed of a cross-linked structure containing ester bonds between poly(meth)acrylic acid (A) and polyalcoholic polymer (B); a resin composition having at least the chemical structures (X) [poly(meth)acrylic acid (A) residue], (Y) [poly(meth)acrylic acid (A)-polyalcoholic polymer (B) residue] and (Z) [metal cross-linked ionic residues], wherein the degree of esterification defined by the equation: degree of esterification=c/(b+c+d) is from 0.01 to 0.5 and the degree of ionization defined by the equation: degree of ionization=c/(b+c+d) is from 0.01 to 0.9 (wherein b, c and d represent the molar ratios of the carbon-oxygen double bond in the chemical structure of the resin composition; and a gas barrier film comprising the same.
A gas barrier film comprising a resin composition comprising a reaction product of poly(meth)acrylic acid (A), a polyalcoholic polymer (B) and a metal (C) as starting materials, wherein said resin composition has at least the chemical structures (X), (Y) and (Z) described below, the degree of esterification defined by the equation (1) is from 0.01 to 0.5 and the degree of ionization defined by the equation (2) is from 0.01 to 0.9:
A container for retort packaging comprising a laminated film having an outermost layer comprising a layer formed of a cross-linked structure containing ester bonds between poly(meth)acrylic acid (A) and a polyalcoholic polymer (B).
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
As the main or only constituent of a layer, which is next to another layer of the same or of a different material: of synthetic resin
Comprising vinyl polymers; comprising acrylic polymers: comprising vinyl acetate or vinyl alcohol polymers
Comprising vinyl polymers; comprising acrylic polymers: comprising acrylic polymers
Layered products comprising a layer of synthetic resin: comprising polyesters
Term ended 6 May 2018 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to a container for retort packaging composed of a specified film and a retort method using the same; and a resin composition and a film comprising the same having a gas barrier property, and a method for producing the same. In more detail, the present invention relates to a container for retort packaging being excellent in hot-water resistance and gas barrier property against oxygen and the like comprising a reaction product of poly(meth)acrylic acid and a polyalcoholic polymer and a retort method using the same, as well as to a resin composition comprising poly(meth)acrylic acid, polyalcoholic polymers and metals and a film being excellent in hot-water resistance, gas barrier property against oxygen and the like, especially in oxygen gas barrier property in a high humidity atmosphere, and a method for producing the same.
The film according to the present invention is not only excellent in hot-water resistance and oxygen gas barrier property but also is able to maintain a good oxygen gas barrier property even after a hot water treatment such as boiling and retort treatment. Therefor, it is suitable as a packaging material for articles, infusion solutions, foodstuffs and beverages that are susceptible to deterioration with oxygen. The film is especially suitable for use in containers for retort packaging since the oxygen gas barrier property is securely maintained even after the film is exposed to hot water or steam for retort treatment.
PVA and poly(meth)acrylic acid and partially hydrolyzed products thereof are water soluble polymers, being widely used for water adsorbents, thickeners, flocculants, dispersants and treatment agents for paper and textiles. Poly(meth)acrylic acid or its partially neutralized product can be formed into a film by casting from its solution and the film obtained has an excellent gas barrier property under dry conditions. However, since this film is strongly hydrophilic, the gas barrier property is remarkably lost under high humidity circumstances besides being readily dissolved in water. Accordingly, this film is not suitable for packaging of foodstuffs containing a large amount of moisture.
An aqueous solution obtained by mixing the aqueous solutions B1 and A was coated on an oriented polyethylene-terephthalate film (PET film; Lumillar.TM. S10, thickness 12 .mu.m, made by Torey Co.) using a reverse roll coater and dried, forming a coating film with a mixing mass ratio as shown in Table 1 of PVA and PAA, having a degree of neutralization of 10%, on the PET film.
The thickness of the coating film was 1 .mu.m. A heat treatment was then applied to the PET film on which the foregoing coating film was formed by making the film to contact with a hot-roll adjusted to 230.degree. C. for 37 seconds. A non-oriented polypropylene film (CPP film, thickness 50 .mu.m) was laminated in a dry condition via an adhesive layer (Adcoat.TM. AD335A made by Toyo Morton Co., curing agent; CAT 10) on the PET film side of the heat-treated film. The CPP film faces of two sheets of the laminated film were overlapped with each other to seal three side lines using Impulse sealer made by Fuji Impulse Co., thereby preparing a packaging bag with an inner dimension of 25 cm.times.20 cm while remaining the coating film to be exposed outside of the bag.
100 ml of distilled water was placed into the bag through the opened port of the bag and the port was sealed with Impulse sealer to prepare a packaged article. The inner diameter surrounded by four seal lines was 20 cm.times.20 cm.