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Timestamp: 2018-10-23 05:30:19
Document Index: 612841181

Matched Legal Cases: ['Application No. 2005', 'Application No. 2005', 'Application No. 06713864', 'Application No. 2005', 'Application No. 2005', 'Application No. 2005', 'Application No. 2005', 'Application No. 2005', 'Application No. 2005', 'Application No. 2006']

Shrink labels - Gunze Limited
United States Patent 9028933
Maruichi, Naoyuki (Shiga, JP)
Nozaki, Takanori (Shiga, JP)
Morikawa, Akira (Shiga, JP)
11/918915
Gunze Limited (Kyoto, JP)
428/34.9
428/480, 428/483, 428/515, 428/521, 525/88, 525/89, 525/93, 525/94, 525/98, 525/191, 525/221, 525/222, 525/241
B32B27/08; B32B7/12; B32B27/18; B32B27/28; B32B27/30; B32B27/36; C08G63/137; C08G63/183; C08G63/199; C08L25/08; C08L25/10; C08L25/14; C08L33/00; C08L33/06; C09J125/04; C09J125/08; C09J125/10; C09J125/14; C09J133/00; G09F3/04; C09J133/06
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20090202851 Heat shrinkable multilayer film and heat shrinkable label 2009-08-13 Maruichi et al. 428/483
20080026170 Heat-Shrinkable Laminate Film, Molded Product and Heat Shrinkable Label Employing the Film, and Container 2008-01-31 Yamada et al. 428/34.9
6627273 Lidstock laminate 2003-09-30 Wolf et al. 428/34.9
6270866 Low temperature heat shrinkable film for labels 2001-08-07 Okuda et al. 428/35.1
6214476 Adhesive resin compositions, laminates, production method thereof and oriented films 2001-04-10 Ikeda et al. 428/476.9
6184289 Styrene resin composition and molding thereof 2001-02-06 Teranishi et al. 525/95
5859116 Clarity and adjustable shrinkage of shrink films using miscible polyester blends 1999-01-12 Shih 524/493
4332858 Multi-layer laminate comprising a modified styrene-butadiene block copolymer 1982-06-01 Saitoh et al. 428/412
EP1752285 2007-02-14 HEAT SHRINK LAMINATE FILM, MOLDING UTILIZING THE FILM, HEAT SHRINK LABEL AND CONTAINER
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JP6141543 February, 1986
JP61116543 June, 1986
JP07082387 March, 1995
JP07137212 May, 1995
JP7137212 May, 1995
JP2001191461A 2001-07-17 HEAT-SHRINKABLE MULTILAYERED FILM
JP2001323082A 2001-11-20 HEAT SHRINKABLE POLYESTER-BASED FILM
JP2002326324 November, 2002 ULTRAVIOLET ABSORBING POLYSTYRENIC RESIN HEAT-SHRINKABLE FILM
JP2002326324A 2002-11-12 ULTRAVIOLET ABSORBING POLYSTYRENIC RESIN HEAT-SHRINKABLE FILM
JP2002331581 November, 2002 HEAT SHRINKABLE POLYESTER FILM
JP2002331581A 2002-11-19 HEAT SHRINKABLE POLYESTER FILM
JP2002351332 December, 2002 SHRINK LABEL
JP2002351332A 2002-12-06 SHRINK LABEL
JP2003277705 October, 2003 PRESSURE-SENSITIVE ADHESIVE FILM FOR SURFACE PROTECTION
JP2003277705A 2003-10-02 PRESSURE-SENSITIVE ADHESIVE FILM FOR SURFACE PROTECTION
JP2006015745A 2006-01-19 HEAT SHRINKABLE LAMINATED FILM, MOLDED ARTICLE USING THE SAME AND HEAT SHRINKABLE LABEL AND CONTAINER
JP200615745 January, 2006
JP2006044179A 2006-02-16 HEAT-SHRINKABLE LAMINATED FILM AND CONTAINER FITTED WITH LABEL CONSISTING OF THE SAME
JP200644179 February, 2006
WO1999029490A1 1999-06-17 LOW TEMPERATURE HEAT SHRINKABLE FILM FOR LABELS
WO/2001/068785 September, 2001 ADHESIVE, PROCESS FOR PRODUCING LAYERED PRODUCT WITH THE ADHESIVE, AND LAYERED PRODUCT
WO2001068785A1 2001-09-20 ADHESIVE, PROCESS FOR PRODUCING LAYERED PRODUCT WITH THE ADHESIVE, AND LAYERED PRODUCT
WO2005118288A1 2005-12-15 HEAT SHRINK LAMINATE FILM, MOLDING UTILIZING THE FILM, HEAT SHRINK LABEL AND CONTAINER
JPS6141543A 1986-02-27
JPH07137212A 1995-05-30
JPS61116543A 1986-06-04
JPH0782387A 1995-03-28
International Search Report from Corresponding International Application No. PCT/JP2006/302723, dated May 23, 2006, 4 pages.
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Abstract No. XP 002601608 of JP 2002-351332, 2 pages.
Office Action for JP Application No. 2005-321237, dated Apr. 6, 2010, 4 pages.
Office Action for JP Application No. 2005-326000, dated Apr. 6, 2010, 4 pages.
http://www.akelastomer.com/jpn/eel/pub/products/tuftec/tuftec—m1943.html, 2 pages.
http://www.akelastomer.com/jpn/eel/pub/products/tuftec/tuftec—m1913.html, 2 pages.
1. A shrink label, comprising a heat-shrinkable multilayer resin film comprising an intermediate layer comprising a polystyrene type resin and outer surface layers comprising a polyester type resin, with said intermediate layer interposed therebetween, as a base film, wherein the polystyrene type resin composing said intermediate layer is a mixed resin of an aromatic vinyl hydrocarbon-conjugated diene copolymer and an aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymer, the polyester type resin composing said outer surface layers contains a component derived from terephthalic acid as a dicarboxylic acid component, and a component derived from ethylene glycol and 1, 4-cyclohexanedimethanol as a diol component, and said intermediate layer is bonded to said outer surface layers with an adhesive layer consisting of a hydrogen addition product of an aromatic vinyl hydrocarbon-conjugated diene copolymer, having at least one functional group selected from the group consisting of a carboxylic group, an acid anhydride group, an amino group, an epoxy group and a hydroxyl group in a molecule of said hydrogen addition product, and the content of aromatic vinyl hydrocarbon components in the hydrogen addition product of an aromatic vinyl hydrocarbon-conjugated diene copolymer is 30 to 80% by weight, wherein an amount of the aromatic vinyl hydrocarbon-conjugated diene copolymer to be mixed is 20 to 80% by weight and an amount of the aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymer to be mixed is 20 to 80% by weight, in the mixed resin composing the intermediate layer.
2. The shrink label according to claim 1, wherein the hydrogen addition product of an aromatic vinyl hydrocarbon-conjugated diene copolymer composing the adhesive layer, having at least one functional group selected from the group consisting of a carboxylic group, an acid anhydride group, an amino group, an epoxy group and a hydroxyl group in a molecule of said hydrogen addition product, is a maleic anhydride modified styrene-ethylene/butylene-styrene block copolymer, an amine modified styrene-ethylene/butylene-styrene block copolymer, an amine modified styrene-butadiene/butylene-styrene block copolymer or a carboxylic acid modified styrene-butadiene/butylene-styrene block copolymer.
3. The shrink label according to claim 2, wherein the aromatic vinyl hydrocarbon-conjugated diene copolymer composing the intermediate layer is a styrene-butadiene-styrene copolymer and/or a styrene-isoprene-butadiene-styrene copolymer.
This application is a nationalization of PCT application PCT/JP 2006/302723 filed on Feb. 16, 2006, claiming priority on Japanese Application No. 2005-122943filed on Apr. 20, 2005; Japanese Application No. 2005-122944 filed on Apr. 20, 2005; Japanese Application No. 2005-321237filed on Nov. 4, 2005; Japanese Application No. 2005-326000 filed on Nov. 10, 2005; Japanese Application No. 2006-002772filed on Jan. 10, 2006; the contents of which are incorporated herein by reference in their entirety.
The present invention relates to a shrink label comprising a multilayer film, which is superior in low temperature resistance, heat resistance, oil resistance, tearing properties along the perforation and appearance and does not peel in covering a container, as a base film, and a heat-shrinkable multilayer resin film which can effectively prevent the deterioration of the content of a container due to ultraviolet light and is superior in the tearing properties along the perforation and the oil resistance when the heat-shrinkable multilayer resin film is used as a shrink label for a container, and a shrink label comprising the heat-shrinkable multilayer resin film as a base film.
In recent years, many containers such as PET bottles and metal cans are covered with shrink labels prepared by performing printing on a base film of a heat-shrinkable resin film.
Patent Document 1: Japanese Kokai Publication Sho-61-41543
Patent Document 2: Japanese Kokai Publication 2002-351332
Patent Document 3: Japanese Kokai Publication 2002-326324
Patent Document 4: Japanese Kokai Publication 2001-323082
In view of the above state of the art, it is an object of the present invention to provide a shrink label comprising a multilayer film, which is superior in low temperature resistance, heat resistance, oil resistance, tearing properties along the perforation and appearance and does not peel in covering a container, as a base film, and a heat-shrinkable multilayer resin film which can effectively prevent the deterioration of the content of a container due to ultraviolet light and is superior in the tearing properties along the perforation and the oil resistance when the heat-shrinkable multilayer resin film is used as a shrink label for a container, and a shrink label comprising the heat-shrinkable multilayer resin film as a base film.
A shrink label of a first aspect of the present invention is a shrink label, comprising a heat-shrinkable multilayer resin film comprising an intermediate layer comprising a polystyrene type resin and outer surface layers comprising a polyester type resin, with said intermediate layer interposed therebetween, as a base film, wherein the polystyrene type resin composing said intermediate layer is an aromatic vinyl hydrocarbon-conjugated diene copolymer, and said intermediate layer is bonded to said outer surface layers with an adhesive layer comprising a hydrogen addition product of an aromatic vinyl hydrocarbon-conjugated diene copolymer, having at least one functional group selected from the group consisting of a carboxylic group, an acid anhydride group, an amino group, an epoxy group and a hydroxyl group in a molecule.
FIG. 1 is a schematic view showing the states of and around a center seal portion in succession of covering steps in employing the shrink label of the first aspect of the present invention. FIG. 2 and FIG. 3 are schematic views showing the states of and around the center seal portion in succession of covering steps in employing conventional shrink labels comprising a multilayer film as a base film.
The present inventors investigated the conditions of covering defects in the case of using conventional shrink labels comprising multilayer films as a base film, and consequently they found that in the shrink label described in Patent Document 2, after center sealing and then a film is shrunk by heat, if the films rub against each other or the film is scratched with a fingernail or a body during transportation of products, peeling occurs between an intermediate layer 1 and an outer surface layer 2, as shown in FIG. 2 (for convenience of comparison, in FIG. 2, peeling occurs at a film edge, but in actual, peeling can occur not only at the film edge but also in a central portion). Further, they found that in the shrink label described in Patent Document 1, after center sealing, peeling occurs between the outer surface layer 2 and an adhesive layer 3′ on the center seal side when the film is shrunk by heat, as shown in FIG. 3.
As the polyester type resin, a resin having a melting temperature of a crystal of 240° C. or lower is preferably used. In the production of the shrink film, it is commonly carried out to reuse trimming pieces of drawing selvage and recycle films as a recycle material. Generally, such recycle materials are mixed with polystyrene type resins as a material for the intermediate layer, but since the polystyrene type resin and the polyester type resin are different in properties such as a melting point, there may be cases where the polyester type resin is extruded in an unmelted state when a film is formed at a temperature suitable for molding the polystyrene type resin. However, by using a polyester type resin having a relatively low melting temperature of a crystal or not having a melting temperature of a crystal, it is possible to prevent an unmelted substance of the polyester type resin from being produced as an extraneous substance in a formed film. On the other hand, when the melting temperature of a crystal is higher than 240° C., a defective condition that in the case of molding the resin as a recycle material, an unmelted substance of the polyester type resin may remain as an extraneous substance in the film to cause defective appearance or defective printing such as intermittence of ink during printing. The melting temperature of a crystal is more preferably 220° C. or lower.
A method of producing the shrink label of the first aspect of the present invention is not particularly limited, but a method of molding the respective layers simultaneously by a co-extrusion process is suitable. For example, in the co-extrusion through a T-die, a method of lamination may be any of a feed block method, a multi-manifold die method, and a combined method thereof. Particularly, by setting an extrusion molding temperature in a location following the portion where resins of the respective layers merge preferably at 230° C. or higher, and more preferably at 240° C. or higher, a multilayer film having high adhesion of all layers can be attained.
A method of producing the shrink label of the second aspect of the present invention is not particularly limited, but a method of molding the respective layers simultaneously by co-extrusion process is suitable. For example, in the co-extrusion through a T-die, a method of lamination may be any of a feed block method, a multi-manifold die method, and a combined method thereof. Particularly, by setting an extrusion molding temperature in a location following the portion where resins of the respective layers merge preferably at 230° C. or higher, and more preferably at 240° C. or higher, a multilayer film having high adhesion of all layers can be attained.
A method of producing the heat-shrinkable multilayer resin film of the present invention is not particularly limited, but a method of molding the respective layers simultaneously by co-extrusion process is suitable. For example, in the co-extrusion through a T-die, a method of lamination may be any of a feed block method, a multi-manifold die method, and a combined method thereof. Particularly, by setting an extrusion molding temperature in a location following the portion where resins of the respective layers merge preferably at 230° C. or higher, and more preferably at 240° C. or higher, a multilayer film having high adhesion of all layers can be attained.
In accordance with the present invention, it is possible to provide a shrink label comprising a multilayer film, which is superior in low temperature resistance, heat resistance, oil resistance, tearing properties along the perforation and appearance and does not peel in covering a container, as a base film, and a heat-shrinkable multilayer resin film which can effectively prevent the deterioration of the content of a container due to ultraviolet light and is superior in the tearing properties along the perforation and the oil resistance when the heat-shrinkable multilayer resin film is used as a shrink label for a container, and a shrink label comprising the heat-shrinkable multilayer resin film as a base film.
As an outer surface layer, a polyester type resin, which uses terephthalic acid as a dicarboxylic acid component and contains 67% by mole of a component derived from ethylene glycol and 33% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component, was used. In addition, a melting point of this polyester type resin could not be measured.
As an intermediate layer, a styrene-butadiene-styrene copolymer (styrene: 78% by weight, butadiene: 22% by weight, Vicat softening point: 72° C., MFR: 5.6 g/10 minutes) was used.
These resins were extruded into a heat-shrinkable multilayer resin film having a five-layer structure of outer surface layer (6 μm)/adhesive layer (1 μm)/intermediate layer (31 μm)/adhesive layer (1 μm)/outer surface layer (6 μm) by a co-extrusion process to form a shrink label. Further, an extrusion molding temperature in a location following the portion where the respective layers merge was set at 230° C.
As an outer surface layer, a polyester type resin, which uses terephthalic acid as a dicarboxylic acid component and contains 70% by mole of a component derived from ethylene glycol, 10% by mole of a component derived from diethylene glycol and 20% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component, was used. In addition, a melting point of this polyester type resin could not be measured.
As an outer surface layer, a polyester type resin, which uses terephthalic acid as a dicarboxylic acid component and contains 67% by mole of a component derived from ethylene glycol and 33% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component, was used.
These resins were extruded into a heat-shrinkable multilayer resin film having a five-layer structure of outer surface layer (6 μm)/adhesive layer (1 μm)/intermediate layer (31 μm)/adhesive layer (1 μm)/outer surface layer (6 μm) by a co-extrusion process to form a shrink label. Further, an extrusion molding temperature in a location following the portion where the respective layers merge was set at 240° C.
As an intermediate layer, a styrene-butadiene-styrene copolymer (styrene: 75% by weight, butadiene: 25% by weight, Vicat softening point: 83° C., MFR: 7.8 g/10 minutes) was used.
These resins were extruded into a heat-shrinkable multilayer resin film having a five-layer structure of outer surface layer (9 μm)/adhesive layer (1 μm)/intermediate layer (25 μm)/adhesive layer (1 μm)/outer surface layer (9 μm) by a co-extrusion process to form a shrink label. Further, an extrusion molding temperature in a location following the portion where the respective layers merge was set at 230° C.
As an intermediate layer, a styrene-isoprene-butadiene-styrene copolymer (styrene: 75% by weight, isoprene 10% by weight, butadiene: 15% by weight, Vicat softening point: 82° C., MFR: 8.0 g/10 minutes) was used.
As an intermediate layer, a compounded resin A (styrene: 84.5% by weight, isoprene 1.5% by weight, butadiene: 14% by weight, Vicat softening point: 70° C., MFR: 9.0 g/10 minutes) prepared by compounding a styrene-isoprene-butadiene-styrene copolymer with a styrene-butadiene-styrene copolymer was used.
As an outer surface layer, a polyester type resin, which uses terephthalic acid as a dicarboxylic acid component and contains 70% by mole of a component derived from ethylene glycol, 10% by mole of a component derived from diethylene glycol and 20% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component, was used.
As an intermediate layer, a resin comprising 70% by weight of the compounded resin A (styrene: 84.5% by weight, isoprene 1.5% by weight, butadiene: 14% by weight, Vicat softening point: 70° C., MFR: 9.0 g/10 minutes) and 30% by weight of a styrene-butadiene-styrene copolymer (styrene: 77% by weight, butadiene: 23% by weight, Vicat softening point: 82° C., MFR: 6.0 g/10 minutes) was used.
As an outer surface layer, a resin comprising 70% by weight of a polyester type resin (melting point: 211° C.) which contains 94% by mole of terephthalic acid and 6% by mole of adipic acid as a dicarboxylic acid component and contains 88% by mole of a component derived from ethylene glycol and 12% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component, and 30% by weight of a polyester type resin which uses terephthalic acid as a dicarboxylic acid component and contains 67% by mole of a component derived from ethylene glycol and 33% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component was used.
As an outer surface layer, a resin comprising 50% by weight of a polyester type resin (melting point: 216° C.) which contains 83% by mole of terephthalic acid, 11% by mole of isophthalic acid and 6% by mole of adipic acid as a dicarboxylic acid component, and uses ethylene glycol as a diol component, and 50% by weight of a polyester type resin which uses terephthalic acid as a dicarboxylic acid component and contains 70% by mole of a component derived from ethylene glycol, 10% by mole of a component derived from diethylene glycol and 20% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component was used.
These resins were extruded into a heat-shrinkable multilayer resin film having a five-layer structure of outer surface layer (8 μm)/adhesive layer (1 μm)/intermediate layer (29 μm)/adhesive layer (1 μm)/outer surface layer (8 μm) by a co-extrusion process to form a shrink label. Further, an extrusion molding temperature in a location following the portion where the respective layers merge was set at 230° C.
As an outer surface layer, a resin comprising 80% by weight of a polyester type resin which uses terephthalic acid as a dicarboxylic acid component and contains 70% by mole of a component derived from ethylene glycol, 10% by mole of a component derived from diethylene glycol and 20% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component, and 20% by weight of a polyester type resin (melting point: 227° C.) which uses terephthalic acid as a dicarboxylic acid component and 1,4-butanediol as a diol component was used.
As an intermediate layer, a resin comprising 70% by weight of the compounded resin B (styrene: 85% by weight, butadiene: 15% by weight, Vicat softening point: 70° C., MFR: 8.0 g/10 minutes) prepared by compounding a styrene-butadiene-styrene copolymer and 30% by weight of a styrene-butadiene-styrene copolymer (styrene: 77% by weight, butadiene: 23% by weight, Vicat softening point: 82° C., MFR: 6.0 g/10 minutes) was used.
A polyester type resin, which uses terephthalic acid as a dicarboxylic acid component and contains 67% by mole of a component derived from ethylene glycol and 33% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component, was used and extruded into a film with a thickness of 45 μm by an extrusion process to form a shrink label.
A styrene-butadiene-styrene copolymer (styrene: 78% by weight, butadiene: 22% by weight, Vicat softening point: 72° C., MFR: 5.6 g/10 minutes) was used and extruded into a film with a thickness of 45 μm by an extrusion process to form a shrink label.
These resins were extruded into a heat-shrinkable multilayer resin film having a five-layer structure of outer surface layer (6 μm)/adhesive layer (1 μm)/intermediate layer (31 μm)/adhesive layer (1 μm)/outer surface layer (6 μm) by a co-extrusion process to form a shrink label. Further, an extrusion molding temperature in a location following the portion where the respective layers merge was set at 250° C.
These resins were extruded into a heat-shrinkable multilayer resin film having a three-layer structure of outer surface layer (6 μm)/intermediate layer (33 μm)/outer surface layer (6 μm) by a co-extrusion process to form a shrink label. Further, an extrusion molding temperature in a location following the portion where the respective layers merge was set at 250° C.
The shrink labels produced in Examples 1 to 13 and Comparative Examples 1 to 4 were evaluated according to the following methods.
(1) Covering Property and Appearance
Both edges of the shrink label were bonded to each other with a mixed solvent of 100 parts by weight of 1,3-dioxolane and 50 parts by weight of cyclohexane to process the label into a tubular form of 6.5 cm in inner diameter. The obtained tubular shrink label is put around a PET bottle having a diameter of 6.5 cm, and the label was shrunk by blowing hot air of 85° C. on the label to cover the bottle. In addition, the perforation was previously provided.
o: There were no delaminations nor crinkles.
After thirty PET bottles (one which the shrink label can cover without producing delaminations or crinkles) covered with the shrink label were left at rest on a hot plate kept at 130° C. for 15 minutes, the condition of each shrink label was visually observed to evaluate the heat resistance according to the following criteria.
o: There were no crinkles nor breaks in the shrink label.
(3) Tearing Property Along Perforation
The shrink labels of thirty PET bottles (one which the shrink label can cover without producing delaminations or crinkles) covered with the shrink label were torn off along the perforation with a hand. The conditions in doing so were observed to evaluate the tearing property along perforation according to the following criteria.
o: The shrink labels could be easily torn off along the perforation.
(4) Oil Resistance
After an edible oil was applied onto each shrink label of thirty PET bottles (one which the shrink label can cover without producing delaminations or crinkles) covered with the shrink label, the condition of the shrink label was visually observed to evaluate the oil resistance according to the following criteria.
(5) Strength Between Layers
A layer including the outer surface layer is taken as a peeling layer, and a layer including the intermediate layer is taken as a layer to be peeled. Strength in peeling the peeling layer from the layer to be peeled in 10 mm in width in the direction of 180° angle was measured.
Covering property Heat Tearing Oil Strength between
and appearance resistance property resistance layers (N/10 mm)
Example 1 ∘ ∘ ∘ ∘ 1.2
Example 2 ∘ ∘ ∘ ∘ 1.3
Example 3 ∘ ∘ ∘ ∘ 1.1
Example 4 ∘ ∘ ∘ ∘ 1.1
Example 5 ∘ ∘ ∘ ∘ 1.3
Example 6 ∘ ∘ ∘ ∘ 1.2
Example 7 ∘ ∘ ∘ ∘ 1.3
Example 8 ∘ ∘ ∘ ∘ 1.1
Example 9 ∘ ∘ ∘ ∘ 1.2
Example 10 ∘ ∘ ∘ ∘ 1.2
Example 11 ∘ ∘ ∘ ∘ 1.2
Example 12 ∘ ∘ ∘ ∘ 1.1
Example 13 ∘ ∘ ∘ ∘ 1.3
Comparative x ∘ x ∘ —
Comparative ∘ x ∘ x —
Comparative x ∘ ∘ ∘ 0.7
Comparative x ∘ ∘ ∘ 0.2
As an intermediate layer, a mixed resin of 50% by weight of a styrene-butadiene block copolymer (styrene: 75% by weight, butadiene: 25% by weight, Vicat softening point: 83° C., MFR: 6.0 g/10 minutes) and 50% by weight of a styrene-butylacrylate copolymer (styrene: 85% by weight, butylacrylate 15% by weight, Vicat softening point: 70° C., MFR: 4.0 g/10 minutes) was used.
As an intermediate layer, a mixed resin comprising 50% by weight of a styrene-butadiene-styrene copolymer (styrene: 75% by weight, butadiene: 25% by weight, Vicat softening point: 83° C., MFR: 6.0 g/10 minutes) and 50% by weight of a styrene-butylacrylate copolymer (styrene: 85% by weight, butylacrylate 15% by weight, Vicat softening point: 70° C., MFR: 4.0 g/10 minutes) was used.
As an intermediate layer, a mixed resin of 30% by weight of a styrene-butadiene block copolymer (styrene: 75% by weight, butadiene: 25% by weight, Vicat softening point: 83° C., MFR: 6.0 g/10 minutes) and 70% by weight of a styrene-butylacrylate copolymer (styrene: 85% by weight, butylacrylate 15% by weight, Vicat softening point: 70° C., MFR: 4.0 g/10 minutes) was used.
As an intermediate layer, a mixed resin comprising 50% by weight of a styrene-isoprene-butadiene-styrene copolymer (styrene: 75% by weight, isoprene 10% by weight, butadiene: 15% by weight, Vicat softening point: 82° C., MFR: 8.0 g/10 minutes) and 50% by weight of a styrene-butylacrylate copolymer (styrene: 85% by weight, butylacrylate 15% by weight, Vicat softening point: 70° C., MFR: 4.0 g/10 minutes) was used.
As an outer surface layer, a mixed resin comprising 70% by weight of a polyester type resin (melting point: 211° C.) which contains 94% by mole of terephthalic acid and 6% by mole of adipic acid as a dicarboxylic acid component and contains 88% by mole of a component derived from ethylene glycol and 12% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component, and 30% by weight of a polyester type resin which uses terephthalic acid as a dicarboxylic acid component and contains 67% by mole of a component derived from ethylene glycol and 33% by mole of a component derived from 1,4-cyclohexanedimethanol as a diol component was used.
As an intermediate layer, a mixed resin comprising 70% by weight of a styrene-butylacrylate copolymer (styrene: 85% by weight, butylacrylate 15% by weight, Vicat softening point: 70° C., MFR: 4.0 g/10 minutes) and 30% by weight of a styrene-isoprene-butadiene-styrene copolymer (styrene: 70% by weight, isoprene 15% by weight, butadiene: 15% by weight, Vicat softening point: 65° C., MFR: 10 g/10 minutes) was used.
A mixed resin of 50% by weight of a styrene-butadiene block copolymer (styrene: 75% by weight, butadiene: 25% by weight, Vicat softening point: 83° C., MFR: 6.0 g/10 minutes) and 50% by weight of a styrene-butylacrylate copolymer (styrene: 85% by weight, butylacrylate 15% by weight, Vicat softening point: 70° C., MFR: 4.0 g/10 minutes) was used and extruded into a film with a thickness of 45 μm by an extrusion process to form a shrink label.
As an intermediate layer, a mixed resin of 50% by weight of a styrene-butadiene block copolymer (styrene: 75% by weight, butadiene: 25% by weight, Vicat softening point: 83° C.) and 50% by weight of a styrene-butylacrylate copolymer (styrene: 85% by weight, butylacrylate 15% by weight, Vicat softening point: 70° C.) was used.
On the shrink labels produced in Examples 14 to 21 and Comparative Examples 1, and 5 to 7, a covering property and appearance, a tearing property along the perforation, oil resistance, and strength between layers were evaluated according to the same methods as those described above. Further, low temperature resistance was evaluated according to the following method.
(Low Temperature Resistance)
After thirty PET bottles (one which the shrink label can cover without producing delaminations or crinkles) covered with the shrink label were dropped from heights of 70 cm with the bottle kept at 4° C., the condition of each shrink label was visually observed to evaluate the low temperature resistance according to the following criteria.
o: There were no breaks from the perforation.
Covering property temperature Tearing Oil Strength between
Example 14 ∘ ∘ ∘ ∘ 1.2
Example 15 ∘ ∘ ∘ ∘ 1.2
Example 16 ∘ ∘ ∘ ∘ 1.1
Example 17 ∘ ∘ ∘ ∘ 1.1
Example 18 ∘ ∘ ∘ ∘ 1.1
Example 19 ∘ ∘ ∘ ∘ 1.2
Example 20 ∘ ∘ ∘ ∘ 1.2
Example 21 ∘ ∘ ∘ ∘ 1.1
As an intermediate layer, a mixture prepared by adding 2.5 parts by weight of 2-(2′-hydroxy-3′-t-butyl-5′-methylphenyl)-5-chlorobenzotriazole as an ultraviolet absorber to 100 parts by weight of a styrene-butadiene copolymer (styrene: 78% by weight, butadiene: 22% by weight, Vicat softening point: 72° C., MFR: 5.6 g/10 minutes) was used.
As an intermediate layer, a mixture prepared by adding 3.0 parts by weight of 2-(2′-hydroxy-3′-t-butyl-5′-methylphenyl)-5-chlorobenzotriazole as an ultraviolet absorber to a mixed resin of 50% by weight of a styrene-butylacrylate copolymer (styrene: 82% by weight, butylacrylate 18% by weight, Vicat softening point: 62° C., MFR: 5.5 g/10 minutes) and 50% by weight of a styrene-butadiene copolymer (styrene: 77% by weight, butadiene: 23% by weight, Vicat softening point: 82° C., MFR: 6.0 g/10 minutes) was used.
As an intermediate layer, a mixture prepared by adding 7.5 parts by weight of 2-(2′-hydroxy-3′-t-butyl-5′-methylphenyl)-5-chlorobenzotriazole as an ultraviolet absorber to 100 parts by weight of a styrene-butadiene copolymer (styrene: 78% by weight, butadiene: 22% by weight, Vicat softening point: 72° C., MFR: 5.6 g/10 minutes) was used.
A shrink label was prepared in a similar manner to Example 22 except that 2-(2′-hydroxy-3′-t-butyl-5′-methylphenyl)-5-chlorobenzotriazole as an ultraviolet absorber was not added.
As an outer surface layer, a polystyrene type resin comprising a styrene-butadiene copolymer (styrene: 78% by weight, butadiene: 22% by weight, Vicat softening point: 72° C., MFR: 5.6 g/10 minutes) was used.
The shrink labels produced in Examples 22 to 24 and Comparative Examples 8 to 11 were evaluated according to the following methods. The results of the evaluation are shown in Table 3.
(1) Ultraviolet Light Transmittance
On the obtained shrink labels, an ultraviolet light (wavelength: 200 to 380 nm) transmittance was measured with a spectrophotometer (Model U-3400, manufactured by Hitachi, Ltd.). A scanning speed was set at 120 nm/min. Incidentally, if the ultraviolet light transmittance is less than 1% at all wavelengths in a range of 200 to 380 nm, it is thought that the shrink label has an adequate ultraviolet light blocking property. Further, a maximum value of the ultraviolet light transmittance at a wavelength of 200 to 380 nm is shown in Table 1.
(2) Presence or Absence of Bleed
After the obtained shrink labels were stored in an atmosphere of 23° C. and 55% in a relative humidity for a week right from film formation, the presence or absence of bleed was verified by wiping the surface of the film with a finger to evaluate it according to the following criteria.
o: There was no substance adhering to the finger.
(3) Contamination of Roll
After the completion of co-extrusion, contamination of a quenching roll of a take-off unit was visually observed to evaluate whether clouding resulting from the bleed of the ultraviolet absorber exists or not.
o: There was no clouding.
(4) Tearing Property Along Perforation
x: Some shrink labels are hard to tear off along the peroration
After an edible oil was applied onto each shrink label of thirty containers covered with the shrink label, the condition of the shrink label was visually observed to evaluate the oil resistance according to the following criteria.
(%) (wavelength at which an Tearing
ultraviolet light transmittance Presence property
exhibit a maximum value or absence Contamination along Oil
in a range of 200 to 380 nm) of bleed of roll perforation resistance
Example 22 0.3(380 nm) ∘ ∘ ∘ ∘
Example 23 0.7(380 nm) ∘ ∘ ∘ ∘
Example 24 0 ∘ ∘ ∘ ∘
Comparative 62(380 nm) ∘ ∘ ∘ ∘
Comparative 2.3(280 nm) ∘ ∘ ∘ x
Comparative 0 x ∘ ∘ x
Comparative 1.3(380 nm) ∘ x x ∘
FIG. 1 is a schematic view showing the states of and around a center seal portion in succession of covering steps in employing the shrink label of the present invention.
FIG. 2 and FIG. 3 are schematic views showing the states of and around the center seal portion in succession of covering steps in employing conventional shrink labels comprising a multilayer film as a base film.
1 intermediate layer
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