Kureha Corporation

Kureha Kagaku Kogyo Kabushiki Kaisha

Tadayoshi Itoh

Takahisa Ueyama

Hitoshi Ishii

Seiichi Ibe

Shota Nambu

Ichiro Kitada

Yuta Sekiya

Hisanori Tobita

Hajime Tsukamoto

Eiichi Hayashi

Shigeyoshi Nakaki

Tsutomu Uehara

Tsuyoshi Ayaki

Takeo Omori

Takeo Higashi

Akihiro Tayama

Provided is a heat-shrinkable multilayer film including: an outer surface layer including a thermoplastic resin; an intermediate layer including a polyamide resin; and an inner surface layer including a sealable resin; the total thickness of the heat-shrinkable multilayer film being from 95 to 160 &#x3bc;m; the thickness of the intermediate layer including the polyamide resin being from 17 to 47 &#x3bc;m; the thickness of the inner surface layer being 55 &#x3bc;m or greater; and the ratio of the thickness of the intermediate layer including the polyamide resin to the total thickness of the heat-shrinkable multilayer film being from 18 to 29%. The heat-shrinkable multilayer film of the present invention has high strength and excellent flexibility. Therefore, the heat-shrinkable multilayer film of the present invention is easily stretched and formed, and can be suitably used as a variety of packaging materials including a food packaging material.

Heat-shrinkable multilayer film

A heat-shrinkable multilayer film according to the present invention is obtained by laminating an inner surface layer that contacts contents, an adhesive layer, and an intermediate layer that is adjacent to the adhesive layer, in this order from an inner side to an outer side. The inner surface layer contains an ethylene-vinyl acetate copolymer, the adhesive layer contains an acid-modified ethylene-based copolymer, and the intermediate layer contains a polyamide-based resin.

A heat-shrinkable multilayer film for being filled with contents, comprising an outer surface layer (A) comprising a heat-resistant thermoplastic resin, an intermediate layer (B) comprising a polyamide-based resin, an inner surface layer (D) comprising an ethylene-based copolymer, and adhesion strength between inner surface layers after treatment with 80&#xb0; C. hot water being not less than 10 N/15 mm. The polyamide-based heat-shrinkable multilayer film obtained in this manner has optimal characteristics for applications that primarily require strength, and has greatly improved self-weldability demanded in packaging films for meat products such as fresh and processed meats.

The invention has for its object to provide a heat-shrinkable laminated film for deep drawing, which has an increased carbon dioxide transmission rate (COTR) and an enhanced ratio (COTR/OTR) of carbon dioxide transmission rate-to-oxygen transmission rate (OTR), and is less susceptible to pinholes. In the inventive heat-shrinkable laminated film for deep drawing, a polyamide resin composition layer (a) containing a polyamide resin mixture comprising 60 to 95% by mass of an aliphatic polyamide resin (A) and 5 to 40% by mass of a polyamide base resin (B) having a heat of crystalline fusion of 5 to 40 J/g is laminated onto a heat-sealing resin layer (a) containing a polyolefin resin via an adhesive resin layer (b).

Thermally shrinkable laminate film for deep drawing, packaged article, and method for packaging of cheese

A polyamide resin-based heat-shrinkable multilayer film having excellent heat shrinkability and strength, as well as a high degree of deep A polyamide resin-based heat-shrinkable multilayer film having excellent heat shrinkability and strength, as well as a high degree of deep drawability as represented a shorter side-basis draw ratio (D/L) in excess of 0.6 between a maximum draw depth (D) and a shorter side length (L) of a mold opening is provided. The multilayer film is characterized by including a surface layer (a) comprising a thermoplastic resin, an intermediate layer (b) comprising a polyamide resin, and a surface layer (c) comprising a sealable resin, wherein (A) the intermediate layer (b) comprises a mixture of an aliphatic polyamide having a melting point of at least 180&#xb0; C., and an amorphous aromatic polyamide comprising a polycondensation product of an aliphatic diamine with is ophthalmic acid and terephthalic acid as main acid components, including 25-45 wt. % of the amorphous aromatic polyamide, and has a thickness exceeding 25% and at most 50% of a total thickness of whole layers, and exhibiting: (B) tensile stresses at an elongation of 100% as measured in a tensile test at 100&#xb0; C., including 3-22 N in at least one of a longitudinal direction (MD) and a transverse direction (TD) and an average of MD and TD values of 3-20N, and (C) a shrinkage in hot water at 90&#xb0; C. of 3 to 20% in each of MD and TD. The film is produced through a process of strictly controlling biaxial stretching ratios and heat-relaxation ratios.

Heat-shrinkable multi-layer film for deep-draw forming, and process for production thereof

A food packaging method is provided in which food is packaged in a package with use of carbon dioxide to benefit from bacteriostatic effects and the food package contains the minimum reduced gas spaces and thereby has a volume substantially equal to the food volume. Tightly-fitting food packages are obtained by the method. A tightly-fitting food package is obtained by: placing at least one kind of foods selected from the group consisting of meats and processed meats in a plastic film package; blowing a carbon dioxide gas in the package to fill the package with the carbon dioxide gas in a volume of 10 to 45 cm3 per 100 g of the food as measured at 0&#xb0; C. and 1 atm; and sealing and refrigerating the package.

Food packaging method

A heat shrinkable multilayer film comprising an outer surface layer (a) formed of a thermoplastic resin, a first intermediate layer (b) formed of a polyamide resin, a second intermediate layer (b) formed of a saponified product of an ethylene-vinyl acetate copolymer, and an inner surface layer (c) formed of a polyolefin resin, wherein the shrink of the heat shrinkable multilayer film in water at 90&#xb0; C. is within a range of from 3 to 45% in each of machine and transverse directions, and the polyamide resin is a mixture of 60 to 90% by weight of an aliphatic polyamide having a melting point of 210&#xb0; C. or higher and 10 to 40% by weight of an aromatic polyamide comprising isophthalic acid and terephthalic acid as main components.

Heat shrinkable multilayer film and packaging material using the same

The present invention provides a laminated film including at least two layers of an outer layer having a printed portion on a surface and an inner layer subjected to an antifogging treatment in which principal resin comprising a solid content of the printed portion is made of chlorinated polypropylene-based resin or urethane-based resin. This antifog laminated film hardly degrades in an antifogging property even when the antifog laminated film subjected to printing on the outer layer of a surface subjected to the antifogging treatment and the printed surface are strongly brought into contact with each other due to an operation of winding the film into a roll or the like.

Antifog laminated film

A stretch-oriented multilayer film suited for use as a freeze packaging material, a deep drawing packaging material, a vertical pillow packaging material, etc., is provided as a stretch-oriented multilayer film, comprising at least three layers including a surface layer (a) comprising a thermoplastic resin, an intermediate layer (b) comprising a polyamide resin and a surface layer (c) comprising a sealable resin, said multilayer film exhibiting an impact energy of at least 1.5 Joule at a conversion thickness of 50 &#x3bc;m at &#x2212;10&#xb0; C. The multilayer film is produced through an inflation process using water having a large capacity as a cooling and a heating medium and including a combination of a high degree of stretching and a high degree of relaxation heat treatment not exercised heretofore.

Low-temperature impact-resistant polyamide-based stretch-oriented multilayer film

A polyester-surfaced heat-shrinkable multilayer film exhibiting good printability and adaptability to various automatic packaging processes is provided, including an outer surface layer (a) comprising a polyester resin, an intermediate layer (b) comprising a polyamide resin and an inner surface layer (c) comprising a sealable resin. The film exhibits a heat-shrinkable stress at 50&deg; C. of at most 3 MPa both in longitudinal direction and in transverse direction, and a hot water shrinkability at 90&deg; C. of at least 20%.

A polyamide resin-based heat-shrinkable multilayer film is caused to satisfy various properties required of a packaging material, especially a food packaging material, at high levels, and particularly exhibit a highest level of heat-shrinkability. The multilayer film comprises at least three layers including an outer surface layer (a) which comprises a polyester resin or a polyolefin resin; an intermediate layer (b) which comprises a mixture of 85-60 wt. % of an aliphatic polyamide resin, and 15-40 wt. % of an aromatic copolyamide resin which is a copolymer of aliphatic diamine/isophthalic acid and aliphatic diamine/terephthalic acid, and an inner surface layer (c) which essentially comprises a copolymer of ethylene and &agr;-olefin having a density below 0.915. The heat-shrinkable multilayer film has been biaxially stretched and then heat-treated to have hot-water shrinkabilities at 80&deg; C. of at least 30% in each of longitudinal/transverse directions and at least 35% in at least one of longitudinal/transverse directions.

Growing community of inventors

Tokyo, Japan

Tadayoshi Itoh