JPH0380425B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas barrier laminated film with an excellent printing finish. (Abbreviated as PVDC) PVDC is a heat-sealable film coated with resin.
This invention relates to a gas-barrier laminated film with an excellent printing finish, which is bonded to the coated surface via an adhesive layer. Conventionally, vacuum packaging, gas replacement packaging, oxygen absorber packaging, desiccant packaging, heat sterilization packaging, and aseptic packaging have been used to prevent deterioration such as moisture absorption, dehumidification, rancidity (oxidation of fats and oils), discoloration, and putrefaction of foods. Packaging techniques such as wrapping are used, and films that block gases such as oxygen and carbon dioxide gas and water vapor are used as packaging materials for these. PVDC is an example of such a gas barrier film.
type films, polyvinyl alcohol resin films, saponified ethylene vinyl acetate copolymer films, polyamide films, acrylonitrile resin films, etc., but these films alone have poor mechanical strength, heat sealability,
Since it has insufficient moisture resistance, water resistance, and heat resistance, it is usually used by laminating it with other plastic films. Especially as a gas barrier film
A commonly used thermoplastic film coated with PVDC is laminated with a heat-sealable film to further impart thermal adhesive properties. However, the purpose of packaging is not just to preserve and prevent deterioration of the packaged items such as food, but also to provide the product name and description of the packaged items, as well as photo printing on the PVDC coated surface for the purpose of eye catching. Beautiful printing such as this is often applied. In such cases, there are very strict requirements regarding the quality of printing, and not only printing misalignment, difference in hue, and stains, but also printing defects such as pinhole-shaped ink omissions and swimming should be handled by packaging material processors. However, when printing on a surface coated with PVDC, pinhole-like ink dropouts may occur, which impairs the beauty of the print. The present inventor has improved such printability defects,
In addition, we searched for a packaging film that has both gas barrier properties and heat seal properties, and as a result of intensive research, we printed the base film in advance and laminated the printed surface with a gas barrier heat seal film. The present invention was achieved by discovering that it is possible to obtain a laminated packaging film that has a good finish, gas barrier properties, and heat sealing properties. That is, the present invention involves printing on a base film, applying a PVDC agent to the printed surface and a heat-sealing film having a softening temperature lower than that of the base film, if necessary, through an anchor coat layer and drying the coating. The laminated packaging film of the present invention is a highly practical packaging film that has a good printing finish, gas barrier properties, and heat sealability. The base film used in the present invention includes transparent films such as cellophane,
Biaxially oriented polypropylene film, biaxially oriented polyethylene terephthalate film, biaxially oriented 6-
Examples include, but are not limited to, general-purpose plastic films such as nylon films and biaxially oriented polyvinyl alcohol films, and laminated films made by combining these with other resin layers, which may be selected as the heat-sealing layer. Those having a softening temperature higher than that of the heat-sealing film, preferably 15° C. or higher, are suitable. When heat-sealing a film that has a softening temperature lower than that of a heat-sealed film, it not only deteriorates in appearance due to deformation and shrinkage, but also may cause problems such as the heat-sealed part breaking depending on the conditions, making it impractical. . Desired printing can be carried out on such a base film by a conventional method. That is, the surface of the base film to be printed is usually subjected to corona treatment in advance, and an anchor coat layer is further provided if necessary, and then a method such as gravure printing or flexography is applied using an ink suitable for the base material to be used. Printed by The printing ink used may be water-soluble, water-dispersed, or solvent-based, with solvent-based inks being particularly preferred. Some solvent-based inks have a nitrocellulose binder type, a polyamide binder type, a chlorinated rubber binder type, a chlorinated polypropylene binder type, a polyester binder type, an ethylene vinyl acetate binder type, a vinyl chloride-vinyl acetate binder type, and a polyurethane binder type. There are binder types and mixed types thereof, and the appropriate one is selected from these depending on the base material used. The printed surface obtained in this way has a beautiful finish with no ink leakage or swimming, unlike the finish of the conventional printed surface printed on the PVDC surface of PVDC coated film. The heat-sealable films used in the present invention include, for example, unstretched films made of polypropylene resin or polyethylene resin, and practical heat-sealable films obtained by laminating these unstretched films and other films. Examples include, but are not limited to, films with a certain temperature, but a film having a softening temperature lower than that of the base film, preferably 15° C. or more lower, is selected. Furthermore, if necessary, the surface to which PVDC is to be applied may be subjected to surface treatment such as corona treatment. The above polypropylene resin is a polypropylene homopolymer, 50% or more of propylene and ethylene, 1-butene, 4-methyl-1-pentene,
Copolymers consisting of one or more α-olefins selected from the group consisting of α-olefins such as 1-hexene and 1-octene, and homopolymers or copolymers of these and other polymers are combined with propylene. 50 ingredients
% or more. In addition, the above polyethylene resin is a polyethylene homopolymer, 50% or more of ethylene and propylene,
1 selected from the group consisting of α-olefins such as 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene, vinyl acetate, acrylic acid, acrylic ester, methacrylic acid, and methacrylic ester It refers to a resin that is a blend of a species or a copolymer consisting of two or more species, a homopolymer thereof, a copolymer thereof, and another polymer in an ethylene content range of 50% or more. Next, in the present invention, examples of the anchor coat layer coating agent provided between the sealing film and the PVDC coating layer, if necessary, include vinyl-based, acrylic-based, ethylene-vinyl acetate-based, rubber-based, polyethyleneimine-based, polybutadiene-based, Examples include aqueous dispersions or organic solvent solutions of polyester-based, polyether-based, polyurethane-based, epoxy-based, polyvinylidene chloride-based adhesives, etc., and the solid content is 0.03 to 1.0 g/m ² by a conventional method, and more preferably 0.1 ~0.5g/
m ² is applied. Next, as the PVDC used in the present invention, for example, one or two types selected from the group consisting of vinylidene chloride monomer, vinyl chloride, acrylonitrile, vinyl acetate, styrene, acrylic acid, acrylic ester, methacrylic acid, and methacrylic ester Examples include an aqueous dispersion or an inorganic or organic solvent solution of a resin copolymerized with the above, but the present invention is not limited thereto as long as it has gas barrier properties. In addition, in order to improve the processing characteristics of the PVDC coating layer,
If necessary, an inorganic anti-blocking agent, wax, antistatic agent, etc. may be added. The method for applying PVDC on the sealant film or the anchor coat layer of the sealant film is to apply and dry the solid content of 1 to 20 g/m ² by a conventional method. If necessary, after application, the gas barrier property, water vapor barrier property, 30 to 50 to improve solvent resistance, slipperiness, etc.
Aging may be performed at ℃ for about 1 to 3 days. In addition, the printed surface of the printed base film and PVDC
As a method for laminating the heat-sealable film coated with the coated surface, conventional lamination methods such as dry lamination, non-solvent lamination, polyethylene extrusion lamination, etc. can be applied. Adhesives used for the above dry lamination include vinyl-based, acrylic-based, ethylene/vinyl acetate-based, polyethyleneimine-based, polybutadiene-based, vinylidene chloride-based, rubber-based, polyester-based, polyether-based, polyurethane-based, epoxy-based, An adhesive such as an isocyanate adhesive is used. Further, the adhesive used in the above non-solvent lamination may be any adhesive as long as it has fluidity when heated and solidifies or hardens after cooling, but polyurethane adhesives are particularly preferred. In addition, in polyethylene extrusion lamination, the anchor coating agent applied to both the adhesive surfaces of the printed base material and the heat-sealable film coated with PVDC is selected from the adhesives listed above for dry lamination. Ru. The laminated film obtained as described above has no color loss in printing ink, has an excellent finish, and can be used as a useful packaging material having gas barrier properties and heat sealability. The present invention will be specifically explained below using Examples. In addition, the method for measuring each physical property in the Examples and Comparative Examples was as follows. Oxygen permeability: ASTM D3984: 20℃, 0%
RH Moisture Permeability: JIS Z0208 40℃, 90% RH Print Finish: Five-color gravure printing including photo printing, and ink transferability and ink swimming condition in highlight areas and halftone areas were visually judged. Example 1 Polypropylene with a softening temperature of 155°C (Noblen)
FS-2011 (manufactured by Sumitomo Chemical Co., Ltd.) was extruded through a T-die to form a film, and then sequentially biaxially stretched to form a film. A corona was applied to one side of biaxially oriented polypropylene (hereinafter abbreviated as OPP) with a thickness of 20μ. The treated surface was then printed in five colors, including a photographic plate, using a polypropylene ink (Lamic FG, manufactured by Dainichiseika Kagyo Co., Ltd.), and the printed surface was coated with a polyurethane adhesive (Takerac A-310). /Takenate A-3, Takeda Pharmaceutical Co., Ltd.
A 50/50 solvent solution of ethyl acetate/toluene (manufactured by Co., Ltd.) was applied and dried so that the solid content was 0.2 g/m ² . Separately, one side of a 50μ thick polyethylene film obtained by forming a film using the inflation method from high-pressure polyethylene (F022, manufactured by Ube Industries, Ltd.) with a softening temperature of 96°C and a density of 0.922 was subjected to corona discharge treatment. did. An aqueous dispersion mainly containing acrylic ester (Movinyl 981, manufactured by Hoechst Synthesis Co., Ltd.) is applied to this treated surface with a solid content.
It was coated and dried to a concentration of 0.3 g/ ^m2 , and then a PVDC aqueous dispersion (Saran Latex L-
511 (manufactured by Asahi Kasei Kogyo Co., Ltd.) was applied and dried so that the solid content was 8 g/m ² . Polyethyleneimine (EL-402, manufactured by Toyo Morton Co., Ltd.) was applied to this PVDC coated surface.
was applied so that the solid content was 0.05 g/m ² and dried. The coated side of this polyethyleneimine-coated polyethylene film and the adhesive-coated side of the adhesive-coated polypropylene film were laminated with polyethylene 20μ extrusion in a conventional manner, and then the performance of the laminated film was measured after aging at 40°C for one day. . The results are shown in Table 1. Example 2 6-nylon (Novamid) with a softening temperature of 205°C
1020 (manufactured by Mitsubishi Chemical Industries, Ltd.) was formed into a film by the tubular method, and then simultaneously biaxially stretched, resulting in a 15μ film.
One side of a biaxially stretched film (hereinafter abbreviated as O-NY) was subjected to corona discharge treatment, and this treated side was printed in the same manner as in Example 1, and a polyurethane adhesive (Polybond HS-30/CA- 30, Sanyo Chemical Industries
An ethyl acetate solution (manufactured by Co., Ltd.) was applied so that the solid content was 3 g/m ² and dried. Separately, linear polyethylene (Linirex AF-3710, manufactured by Nippon Petrochemical Co., Ltd.) consisting of ethylene and 1-butene and having a softening temperature of 115°C and a density of 0.935 was used as T.
Corona discharge treatment was applied to one side of a 40μ thick polyethylene film produced by die-casting, and a polyester adhesive (Vylon 300, manufactured by Toyobo Co., Ltd./Coronate L, Nippon Polyurethane Industries, Ltd.) was applied to this treated surface. Co., Ltd. solution to a solid content of 0.25 g/m ² , dried, and then applied water-dispersed PVDC (Crehalon Latex DO-870) on this surface.
(manufactured by Kureha Kagaku Co., Ltd.) was applied to a solid content of 5 g/m ² and dried. This PVDC coated surface and the O-NY adhesive coated surface were dry laminated using a conventional method, and after aging at 40°C for 2 days, the performance of the obtained laminated film was measured and the results were reported. It is shown in Table 1. Example 3 A 12μ polyethylene terephthalate film (hereinafter referred to as
Abbreviated as PET film. ) was subjected to corona discharge treatment, and this treated side was printed using the same ink as in Example 1, and a polyurethane non-solpent type adhesive (LF188-D, Dainippon Ink Industries, Ltd.) was applied on the printed surface. ) manufactured by ) was applied at a concentration of 1.0 g/m ² . Separately, a polypropylene film (hereinafter referred to as CPP film) with a thickness of 30 μm was produced using a T-die casting method using a propylene random polymer (Noblen FL6411, manufactured by Sumitomo Chemical Co., Ltd.) consisting of propylene and ethylene and having a softening temperature of 135°C. ), and a polyurethane aqueous dispersion (Seikabond W-86-1/C-87, manufactured by Dainichiseika Kagyo Co., Ltd.) was applied to this treated surface to a solid content of 0.4 g/ ^m2 . Apply as shown, dry, and apply solution type to this applied surface.
PVDC (Saran Resin F-216, manufactured by Asahi Kasei Corporation)
A solution of 100 parts and 0.5 part of paraffin wax with a melting point of 63°C (solvent tetrahydrofuran/toluene = 50/50) was applied so that the solid content was 3 g/m ² , dried, and further heated at 40°C for 2 Aging was performed for several days. This PVDC-coated surface and the adhesive-coated surface of the printed PET film were bonded together by heating, and then at 40°C.
After aging for 3 days, the performance of the obtained laminated film was measured, and the results are shown in Table 1. Comparative Example 1 Corona discharge treated OPP obtained in Example 1
A propylene dichloride/toluene = 50/50 solvent solution of polyisocyanate adhesive (Titabond 104, manufactured by Nippon Soda Co., Ltd.) was applied to the treated surface of the film so that the solid content was 0.15 g/ ^m2 , and then dried. , the same PVDC as in Example 1 was applied to this coated surface with a solid content of 8 g/m ²
It was applied and dried so that it looked like this. On this PVDC coating layer, the same design was printed using the same ink as in Example 1, and the same polyurethane adhesive as in Example 1 was applied at a solid content of 0.2 g/m ² . Separately, the same polyethyleneimine as in Example 1 was applied as a solid content of 0.05 g/m ² on the treated surface of the corona discharge-treated CPP film obtained in Example 3.
This coated surface and the adhesive coated surface of the printed OPP film were bonded using a conventional method using high-pressure polyethylene.
After extrusion lamination using 20 μm, aging was performed at 40° C. for 1 day. The performance of the obtained laminated film was measured and the results are shown in Table 1. Comparative Example 2 PVDC (Asahi Kasei Industries, Ltd.) was applied to the corona discharge treated surface of the biaxially stretched 6-nylon film obtained in Example 2.
100 parts of Saran range F-216) and 0.5 part of paraffin wax with a melting point of 63°C are dissolved in a solvent consisting of 50 parts of tetrahydrofuran and 50 parts of toluene, and the solid content is
After coating and drying to a concentration of 3 g/m ² and aging at 40°C for 2 days, the same ink (Lamic FG) as in Example 1 was applied to the PVDC surface of this PVDC-coated biaxially stretched 6-nylon film. Printed with the same design. Polyurethane adhesive is applied to the printed surface of this printed PVDC-coated biaxially oriented 6-nylon film.
That is, the coated surface obtained by applying and drying the ethyl acetate solution of Polybond NS-30/CA-30 manufactured by Sanyo Chemical Industries, Ltd. shown in Example 2 to a solid content of 3 g/ ^m2 ; , density 0.935 obtained in Example 2,
The corona-treated surface of a polyethylene film made of 1-butene and ethylene having a softening temperature of 115°C was laminated and aged at 40°C for 2 days. The performance of the obtained laminated film was measured and the results are shown in Table 1. Although gas barrier properties and water vapor barrier properties were excellent, swimming of ink was observed on the printed surface, and the print finish was unsatisfactory. As can be seen from the results in Table 1 above, the conventional method, that is, the laminated film that is printed on a PVDC coated surface and then laminated with a sealant film, has pinhole-like ink dropout and ink swimming on the printed surface.
Although the finish was unsatisfactory for beautiful printing, the laminated film of the present invention has gas barrier properties,
Both water vapor barrier properties and printing finish were good. 【table】

Claims (1)

[Claims] 1. The printed surface of a base film printed on one side and the polyvinylidene chloride resin coated surface of a heat-sealable film having a polyvinylidene chloride resin coated layer on one side are bonded together via an adhesive layer. A gas barrier laminated film with an excellent printing finish. 2. The gas-barrier laminated film according to claim 1, wherein the heat-sealable film coated with polyvinylidene chloride resin is a non-stretched polypropylene film or a non-stretched polyethylene film. 3. The gas-barrier laminated film according to claim 2, wherein the printed base film is a biaxially oriented polyamide film. 4. The gas-barrier laminated film according to claim 2, wherein the printed base film is a biaxially oriented polypropylene film. 5. The gas-barrier laminated film according to claim 2, wherein the printed base film is a biaxially oriented polyester film. 6. The gas-barrier laminated film according to claim 2, wherein the printed base film is cellophane.