PACKAGING MATERIAL

Abstract

The present invention aims to provide a packaging material having excellent printed image quality as well as excellent laminate strength and heat sealability. Provided is a packaging material including at least: a base film, a primer layer, a printed layer, an adhesive layer, and a sealant film in a stated order, the primer layer being formed of a primer composition containing a water-soluble polyvalent metal salt, a chlorinated polyolefin emulsion, and at least one selected from the group consisting of an acrylic emulsion, a vinyl acetate emulsion, and a urethane-modified polyester resin, the printed layer being formed of a printing ink containing a polyester polyurethane resin, the adhesive layer being formed of an aliphatic ester adhesive.

Claims

1. A packaging material comprising at least: a base film; a primer layer; a printed layer; an adhesive layer; and a sealant film in a stated order, the primer layer being formed of a primer composition containing a water-soluble polyvalent metal salt, a chlorinated polyolefin emulsion, and at least one selected from the group consisting of an acrylic emulsion, a vinyl acetate emulsion, and a urethane-modified polyester resin, the printed layer being formed of a printing ink containing a polyester polyurethane resin, the adhesive layer being formed of an aliphatic ester adhesive.

2. The packaging material according to claim 1, wherein the aliphatic ester adhesive contains a urethane bond.

3. The packaging material according to claim 1, wherein the base film is a polypropylene film or a polyester film.

4. The packaging material according to claim 1, wherein the sealant film is an aluminized polypropylene film.

Description

EXAMPLES

[0147] The present invention is more specifically described hereinbelow referring to, but not limited to, examples. The “part(s)” and “%” in examples and comparative examples are on the mass basis unless otherwise specified.

<Base Film>

[0148] OPP (biaxially oriented polypropylene film, PYLEN Film-OT P-2161, thickness of 25 μm, produced by Toyobo co., Ltd.) PET (biaxially oriented polyester film, E-5102, thickness of 12 μm, produced by Toyobo co., Ltd.)

<Primer Composition>

[0149] Water-soluble polyvalent metal salt (calcium acetate, calcium formate)
Chlorinated polyolefin emulsion (SUPERCHLON E-604, chlorination degree of 21%, produced by Nippon Paper Industries Co., Ltd.)
Acrylic emulsion (VINYBLAN 2687, glass transition temperature of 20° C., produced by Nissin Chemical Co., Ltd.)
Vinyl acetate emulsion (VINYBLAN 1129, produced by Nissin Chemical Co., Ltd.)
Urethane-modified polyester resin (Impranil DLS, glass transition temperature of −51° C., produced by Covestro AG)
Urethane-modified polyether resin (NeoRez R650, produced by DSM)
Urethane-modified polycarbonate resin (NeoRez R986, produced by DSM)
Surfactant (Olfine E1010, 100% active ingredient, HLB13, produced by Nissin Chemical Co., Ltd.)

Water

[0150] The materials were blended as shown in Table 1 and stirred to be mixed. Thus, primer compositions P1 to P12 were produced.

TABLE-US-00001 TABLE 1 Primer composition P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 Calcium acetate (solid content) 2 0.5 10 2 2 2 2 — 2 2 2 2 Calcium formate (solid content) — — — — — — — 2 — — — — Chlorinated polyolefin emulsion (solid content) 2 2 2 2 2 2 2 2 — 2 2 2 Acrylic emulsion (solid content) 5 5 5 — 0.5 10 — 5 5 — — — Vinyl acetate emulsion (solid content) — — — 5 — — — — — — — — Urethane-modified polyester resin — — — — — — 5 — — — — — (solid content) Urethane-modified polyether resin — — — — — — — — — — 5 — (solid content) Urethane-modified polycarbonate resin — — — — — — — — — — — 5 (solid content) Surfactant 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Water 90.5 92 82.5 90.5 95 85.5 90.5 90.5 92.5 95.5 90.5 90.5 Total (parts by mass) 100 100 100 100 100 100 100 100 100 100 100 100

<Printing Ink>

[0151] The following polyester polyurethane resin varnishes A to C were produced as polyester polyurethane resins.

(Polyester Polyurethane Resin Varnish A)

[0152] A pressure polymerization vessel equipped with a thermometer and a stirrer was charged with 200.0 parts by mass of a polyester diol that was obtained by dehydration copolymerization of 1,6-hexanediol and phthalic acid and had a weight average molecular weight (Mw) of 2,000, 5.4 parts by mass of dimethylolpropionic acid, 21.9 parts by mass of hexamethylene diisocyanate, and 265.5 parts by mass of methyl ethyl ketone. They were reacted at 75° C. for seven hours.

[0153] Thereafter, 3.9 parts by mass of triethylamine and 539.5 parts by mass of pure water were added and the methyl ethyl ketone was distilled under reduced pressure, whereby a polyester polyurethane resin varnish A was obtained. The polyester polyurethane resin varnish A contained, as a solid content, 30% of a self-emulsifying polyurethane resin having a weight average molecular weight (Mw) of 24,000 and a theoretical acid value of 9.9 mg KOH/g.

(Polyester Polyurethane Resin Varnish B)

[0154] A pressure polymerization vessel equipped with a thermometer and a stirrer was charged with 200.0 parts by mass of a polyester diol that was obtained by dehydration copolymerization of 3-methyl-1,5-pentanediol and phthalic acid and had a weight average molecular weight (Mw) of 2,000, 5.4 parts by mass of dimethylolpropionic acid, 21.9 parts by mass of hexamethylene diisocyanate, and 265.5 parts by mass of methyl ethyl ketone. They were reacted at 75° C. for seven hours.

[0155] Thereafter, 3.9 parts by mass of triethylamine and 539.5 parts by mass of pure water were added and the methyl ethyl ketone was distilled under reduced pressure, whereby a polyester polyurethane resin varnish B was obtained. The polyester polyurethane resin varnish B contained, as a solid content, 30% of a self-emulsifying polyurethane resin having a weight average molecular weight (Mw) of 24,000 and a theoretical acid value of 9.9 mg KOH/g.

(Polyester Polyurethane Resin Varnish C)

[0156] A pressure polymerization vessel equipped with a thermometer and a stirrer was charged with 200.0 parts by mass of a polyester diol that was obtained by dehydration copolymerization of a diol component having a mass ratio of 1,6-hexanediol and 3-methyl-1,5-pentanediol of 1:1 and phthalic acid and had a weight average molecular weight (Mw) of 2,000, 5.4 parts by mass of dimethylolpropionic acid, 21.9 parts by mass of hexamethylene diisocyanate, and 265.5 parts by mass of methyl ethyl ketone. They were reacted at 75° C. for seven hours.

[0157] Thereafter, 3.9 parts by mass of triethylamine and 539.5 parts by mass of pure water were added and the methyl ethyl ketone was distilled under reduced pressure, whereby a polyester polyurethane resin varnish C was obtained. The polyester polyurethane resin varnish C contained, as a solid content, 30% of a self-emulsifying polyurethane resin having a weight average molecular weight (Mw) of 25,000 and a theoretical acid value of 9.9 mg KOH/g.

[0158] The weight average molecular weight (Mw) was determined as a polystyrene-equivalent weight average molecular weight by chromatography using Water 2690 (produced by Waters Corporation) as a GPC device and PLgel 5p MIXED-D (produced by Polymer Laboratories) as a column.

[0159] The theoretical acid value means the number of milligrams of potassium hydroxide theoretically needed to neutralize 1 g of the polyurethane resin, arithmetically determined based on factors such as the molecular weight of the carboxy group-containing compound used as a synthesis component of the polyurethane resin, the mixing ratio of the compound, and the number of carboxy groups in the molecule of the compound.

[0160] The following resins were provided for comparison.

Urethane-modified polyether resin (NeoRez R-966, produced by DSM)
Urethane-modified polycarbonate resin (Superflex 420NS, produced by Dai-Ichi Kogyo Seiyaku Co., Ltd.)
Acrylic emulsion (YODOSOL AD173, produced by Henkel)

(Pigment-Dispersing Component)

[0161] The following aqueous resin varnish was produced as a pigment-dispersing component.

[0162] An amount of 2.5 parts by mass of potassium hydroxide was dissolved in 77.5 parts by mass of water, and in the solution was dissolved 20 parts by mass of an acrylic acid/n-butyl acrylate/benzyl methacrylate/styrene copolymer having a glass transition temperature of 40° C., a weight average molecular weight (Mw) of 30,000, and an acid value of 185 mg KOH/g. Thus, an aqueous resin varnish having a solid content of 20% was obtained.

[0163] Colorants, the pigment-dispersing component, and an aqueous medium were mixed to prepare aqueous ink bases.

(Preparation of Yellow)

[0164] An amount of 23.7 parts by mass of the aqueous resin varnish and 64.3 parts by mass of water were mixed to prepare a resin varnish for pigment dispersion. The varnish and 12 parts by mass of a yellow pigment (product name: Novoperm Yellow 4G 01, produced by Clariant) were stirred and mixed, and then kneaded in a wet-type circulation mill, whereby an aqueous ink base (yellow) was obtained.

(Preparation of Magenta)

[0165] An amount of 23.7 parts by mass of the aqueous resin varnish and 64.3 parts by mass of water were mixed to prepare a resin varnish for pigment dispersion. The varnish and 12 parts by mass of a magenta pigment (product name: Ink Jet Magenta E5B 02, produced by Clariant) were stirred and mixed, and then kneaded in a wet-type circulation mill, whereby an aqueous ink base (magenta) was obtained.

(Preparation of Cyan)

[0166] An amount of 23.7 parts by mass of the aqueous resin varnish and 64.3 parts by mass of water were mixed to prepare a resin varnish for pigment dispersion. The varnish and 12 parts by mass of a cyan pigment (product name: Heliogen Blue L 7101 F, produced by BASF SE) were stirred and mixed, and then kneaded in a wet-type circulation mill, whereby an aqueous ink base (cyan) was obtained.

(Preparation of Black)

[0167] An amount of 23.7 parts by mass of the aqueous resin varnish and 64.3 parts by mass of water were mixed to prepare a resin varnish for pigment dispersion. The varnish and 12 parts by mass of carbon black (product name: Printex 90, produced by Degussa) were stirred and mixed, and then kneaded in a wet-type circulation mill, whereby an aqueous ink base (black) was obtained.

(Preparation of White)

[0168] An amount of 40.0 parts by mass of the aqueous resin varnish and 20.0 parts by mass of water were mixed to prepare a resin varnish for pigment dispersion. The varnish and 40 parts by mass of titanium oxide (product name: R-960, produced by Du Pont) were stirred and mixed, and then kneaded in a wet-type circulation mill, whereby an aqueous ink base (white) was obtained.

Surfactant (Surfynol 465, solid content of 100%, HLB 13, produced by EVONIK)
Propylene glycol

Water

[0169] The above materials were blended as shown in Table 2, and stirred to be mixed. Thus, printing inks 1 to 13 were produced.

TABLE-US-00002 TABLE 2 Printing ink 1 2 3 4 5 6 7 8 9 10 11 12 13 Aqueous ink base Yellow (colorant: 12%) — 34 — — — — — — — — — — — Magenta (colorant: 12%) — — 34 — — — — — — — — — — Cyan (colorant: 12%) — — — 25 — — — — — — — — — Black (colorant: 12%) 34 — — — — 34 34 34 34 34 34 34 34 White (colorant: 40%) — — — — 25 — — — — — — — — Polyester polyurethane resin Varnish A 5 5 5 5 5 1 10 — — — — — — (solid content) Varnish B — — — — — — — 5 — — — — — Varnish C — — — — — — — — 5 — — — — Urethane-modified polyether resin (solid content) — — — — — — — — — — 5 — — Urethane-modified polycarbonate resin (solid content) — — — — — — — — — — — 5 — Acrylic emulsion (solid content) — — — — — — — — — — — — 5 Surfactant 1 1 1 1 1 1 1 1 1 1 1 1 1 Propylene glycol 35 35 35 40 35 40 30 30 30 40 35 30 35 Water 25 25 25 29 34 24 25 30 30 25 25 30 25 Total (parts by mass) 100 100 100 100 100 100 100 100 100 100 100 100 100

<Adhesive>

[0170] A315/A50 (aliphatic polyester adhesive, solution of TAKELAC
A-315/TAKENATE A-50 in ethyl acetate, produced by Mitsui Chemicals, Inc.)
A385/A50 (aliphatic polyester adhesive, solution of TAKELAC
A-385/TAKENATE A-50 in ethyl acetate, produced by Mitsui Chemicals, Inc.)
A969/A5 (aromatic polyether adhesive, solution of TAKELAC
A-969V/TAKENATE A-5 in ethyl acetate, produced by Mitsui Chemicals, Inc.)
A515/A3 (aromatic polyester adhesive, solution of TAKELAC
A-515/TAKENATE A-3 in ethyl acetate, produced by Mitsui Chemicals, Inc.)

<Sealant Film>

[0171] CPP (cast polypropylene film, PYLEN Film-CT P-1128, thickness of 25 μm, produced by Toyobo co., Ltd.)
VM-CPP (aluminized cast polypropylene film, thickness of 25 μm, produced by Mitsui Chemicals Tohcello, Inc.)

Examples 1 to 22, Comparative Examples 1 to 15

[0172] Packaging materials of Examples 1 to 22 and Comparative Examples 1 to 15 were produced using materials shown in Table 3 by the following method.

[0173] Corona discharge treatment was performed on one surface of a base film, and the primer composition was applied to the treated surface to form a primer layer having a thickness of 0.3 μm.

[0174] Next, on the primer layer surface was performed printing using a printer PX105 (produced by Seiko Epson Corp.) including cartridges filled with printing inks, whereby a printed layer having a thickness of 2 μm was formed.

[0175] Then, the adhesive was applied to the printed layer surface to form an adhesive layer having a dry thickness of 5 μm, and the sealant film was laminated thereon (in the case of including a deposition layer, the sealant film was laminated such that the deposition layer side surface was in contact with the adhesive layer). Thus, a packaging material was produced.

<Evaluation of Packaging Material>

(Laminate Strength)

[0176] The packaging materials of Examples 1 to 22 and Comparative Examples 1 to 15 after standing at 40° C. for three days were each cut to a width of 15 mm to prepare a specimen.

[0177] The specimen was subjected to T-peeling using a peel tester (produced by Yasuda Seiki Seisakusho, Ltd.) to determine the peel strength between the base film and the sealant film. The laminate strength was evaluated based on the following criteria.

Good: The strength upon peeling of the packaging material was more than 100 g/15 mm.
Fair: The strength upon peeling of the packaging material was not less than 50 g/15 mm and not more than 100 g/15 mm.
Poor: The strength upon peeling of the packaging material was less than 50 g/15 mm.

(Heat Sealability)

[0178] The packaging materials of Examples 1 to 22 and Comparative Examples 1 to 15 were each formed into a bag using an impulse sealer (produced by Fujiimpulse Co., Ltd.), and the resulting bag was cut to a size of 15 mm×100 mm to prepare a specimen.

[0179] Then, the specimen was subjected to T-peeling using a peel tester (produced by Yasuda Seiki Seisakusho, Ltd.) at a tensile speed of 300 mm/min to determine the seal strength. The heat sealability was evaluated based on the following criteria.

Good: The seal strength was 1 kg/15 mm or more.
Poor: The seal strength was less than 1 kg/15 mm.

(Printed Image Quality)

[0180] The packaging materials of Examples 1 to 22 and Comparative Examples 1 to 15 were each visually observed for thickening of a thin line due to blurring of the printed layer, and the printed image quality was evaluated based on the following criteria.

[0181] The printed layer used was a printed thin line having a width of 0.3 mm.

Good: No blurring was observed, and the thin line was printed with the original width.
Fair: The thin line was partially widened to less than twice the original width.
Poor: The entire line was widened to twice or more the original width.

TABLE-US-00003 TABLE 3 Example Example Example Example Example Example Example Example Example Example 1 2 3 4 5 6 7 8 9 10 Printing ink 1 2 3 4 5 6 7 8 9 1 Primer composition P1 P1 P1 P1 P1 P1 P1 P1 P1 P2 Base film OPP OPP OPP OPP OPP OPP OPP OPP OPP OPP Sealant film VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP Adhesive A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 Laminate strength Good Good Good Good Good Fair Good Good Good Good 130 150 120 150 120 90 150 120 110 130 Heat sealability Good Good Good Good Good Good Good Good Good Good 1.3 1.6 1.2 1.4 1.3 1.3 1.4 1.3 1.3 1.3 Printed image Good Good Good Good Good Good Good Good Good Good quality Example Example Example Example Example Example Example Example Example 11 12 13 14 15 16 17 18 19 Printing ink 1 1 1 1 1 1 1 1 1 Primer composition P3 P4 P5 P6 P7 P1 P1 P1 P1 Base film OPP OPP OPP OPP OPP PET PET OPP PET Sealant film VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP CPP VM-CPP VM-CPP CPP Adhesive A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A385/A50 A385/A50 Laminate strength Good Good Fair Good Good Good Good Good Good 110 130 90 140 150 180 100 120 170 Heat sealability Good Good Good Good Good Good Good Good Good 1.3 1.3 1.3 1.3 1.5 1.5 1.3 1.5 1.5 Printed image Good Good Good Good Good Good Good Good Good quality Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative Example Example Example Example Example Example Example Example Example 20 21 22 1 2 3 4 5 6 Printing ink 1 1 1 1 10 11 12 13 1 Primer composition P1 P8 P8 P1 P1 P1 P1 P1 Base film PET OPP PET OPP OPP OPP OPP OPP OPP Sealant film VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP Adhesive A385/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A315/A50 A969/A5 Laminate strength Good Good Good — Poor Poor Poor Poor Poor 110 130 100 — 15 20 15 15 40 Heat sealability Good Good Good — Good Good Good Good Good 1.5 1.3 1.3 — 1.3 1.3 1.3 1.3 1.2 Printed image Good Good Good Poor Good Good Good Good Good quality Compar- Compar- Compar- Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative ative ative ative Example Example Example Example Example Example Example Example Example 7 8 9 10 11 12 13 14 15 Printing ink 1 1 1 1 1 1 1 1 1 Primer composition P1 P1 P1 P1 P1 P9 P10 P11 P12 Base film OPP PET PET PET PET OPP OPP OPP OPP Sealant film VM-CPP CPP CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP VM-CPP Adhesive A515/A3 A969/A5 A515/A3 A969/A5 A515/A3 A315/A50 A315/A50 A315/A50 A315/A50 Laminate strength Poor Poor Poor Poor Poor Poor Poor Poor Poor 40 40 40 40 40 15 20 40 40 Heat sealability Good Good Good Good Good Good Good Good Good 1.1 1.2 1.1 1.3 1.1 1.3 1.3 1.3 1.3 Printed image Good Good Good Good Good Good Good Good Good quality

[0182] It was confirmed that the packaging materials of the examples had excellent printed image quality as well as laminate strength and heat sealability even in the case of including, as a base film or a sealant film, an oriented or cast polypropylene film, an oriented or cast polyester film, a polypropylene film including an inorganic oxide-deposited layer, or the like.

[0183] In contrast, in the packaging material of Comparative Example 1 including no primer layer, blurring of the printed layer occurred and widening of the thin line to twice or more the original width was observed. Moreover, layers are not sufficiently bonded to each other, and therefore, evaluation on the laminate strength and heat sealability could not be performed.

[0184] In the case of the packaging materials of Comparative Examples 2 to 5 which were produced using a printing ink containing no polyester polyurethane resin, the laminate strength was insufficient.

[0185] In the case of the packaging materials of Comparative Examples 6 to 11 including no adhesive layer formed of an aliphatic ester adhesive, the laminate strength was insufficient too.

[0186] The laminate strength was also insufficient in Comparative Example 12 in which the primer layer contained no chlorinated polyolefin emulsion, Comparative Example 13 in which the primer layer did not contain the at least one selected from the group consisting of an acrylic emulsion, a vinyl acetate emulsion, and a urethane-modified polyester resin, Comparative Example 14 in which the at least one selected from the group consisting of an acrylic emulsion, a vinyl acetate emulsion, and a urethane-modified polyester resin was replaced by a urethane-modified polyether in the primer layer, and Comparative Example 15 in which the at least one selected from the group consisting of an acrylic emulsion, a vinyl acetate emulsion, and a urethane-modified polyester resin was replaced by a urethane-modified polycarbonate in the primer layer.

INDUSTRIAL APPLICABILITY

[0187] The packaging material of the present invention has excellent printed image quality as well as excellent laminate strength and heat sealability, and therefore is widely usable in the field of packaging materials for food, drugs, or the like.