JPH0358299B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin film used as a label for canned goods, carbonated drink containers, and youth drink containers. The label of the present invention is particularly useful as a label for bottles made of glass, polyvinyl chloride, or polyethylene terephthalate (PET). Glass, as shown in Figure 1, is used as a disposable container for liquids such as carbonated drinks, youth, beer, and sake.
A pre-labeled bottle is used, in which a shrink label 1 made of a cylindrical uniaxially stretched polyvinyl chloride film is attached to a 16-ounce hollow bottle 2 made of PET by heat shrinkage stress. This pre-label bottle has been widely used since the 1970s because it has the following advantages when the bottle material is glass. (1) By labeling at the bottle manufacturer,
To prevent damage to glass bottles on a transportation bottling line from a bottle manufacturer to a filling place or during bottle transfer. (2) The plastic label prevents noise and the scattering of glass pieces when the bottle breaks. (3) The wide, all-around plastic label allows metallic tone photo printing with glossy gravure printing, and when the label material is polyvinyl chloride film, vivid gravure printing using the transparent area is possible, increasing the display effect. Conventionally, resin films for shrink labels used for pre-labeled bottles that are wrapped from the neck to the bottom have been transparent polyvinyl chloride uniaxially stretched films with a wall thickness of approximately 50 to 70 microns, and 80 to 130 microns.
An opaque expanded polystyrene jacket is used. Among these labels, polyvinyl chloride stretched film labels are more effective in preventing glass fragments from scattering when a glass bottle is broken. Although this stretched film of polyvinyl chloride and expanded polystyrene can be used for gravure printing, it has the disadvantage that it cannot be used for offset multicolor printing, which allows precision and fine print. Furthermore, foamed polystyrene jackets have a heat resistance of up to 80°C at most, making them unsuitable as containers that are sterilized with hot water of 85°C or higher or retort sterilized. Regarding polyvinyl chloride uniaxially stretched film, it is a shrinkable film with a dimensional shrinkage rate of 58 to 67% in the transverse direction and 7 to 18% in the longitudinal direction at 120°C; Because of the high dimensional shrinkage rate, the end 1a of the shrink label 1 located at the neck of the bottle becomes uneven as shown in FIG. 2, resulting in poor appearance. In addition, the barcode 1b indicating the product number was sometimes distorted, and the computer sometimes misread it. The reason why the shrinkable film of polyvinyl chloride has a high dimensional shrinkage rate of 7 to 18% in the longitudinal direction is presumed to be due to the fact that the stretched film is produced in the mandrel stretching direction. The present inventors have solved this drawback of polyvinyl chloride Shrink labels by using synthetic paper (Japanese Patent Publication No. 46-40794, Japanese Patent Application Laid-Open No. 56-118437) consisting of a stretched film of polypropylene containing fine inorganic powder. Synthetic paper coated with an acrylic antistatic polymer on the surface of the paper to improve offset printability (Japanese Patent Application Laid-open Nos. 10624-1983, 48-40883, and 50
-161478, 57-149363) and evaluated it.
The lateral dimensional shrinkage rate at 120℃ is 1-2%,
The dimensional shrinkage rate in the vertical direction was 2 to 3%, and the adhesion to the bottle was weak, resulting in the label easily coming off the bottle. The present invention solves the disadvantage of using polypropylene resin synthetic paper due to the low dimensional shrinkage in the transverse direction by using a specific polypropylene resin composition as a composition constituting the base layer. This problem can be solved by increasing the shrinkage rate of the stretched film. That is, the present invention uses a propylene copolymer (A) selected from the following (a ₁ ) to (a ₃ ) ~ 25 to 84% by weight, polybutene-1 (B) 1 to 30% by weight, and a melting point of 80%. ~110℃
On at least one side of a uniaxially stretched film for a base layer formed from a resin composition containing 10 to 40% by weight of an olefin resin (C) and 5 to 30% by weight of an inorganic fine powder (D). , 100-80% by weight of polypropylene ( _A4 ) having a melting point 10°C or more higher than the propylene copolymer of (A) above and 0-20% by weight of inorganic fine powder.
(However, it is lower than the inorganic fine powder content of the base layer)
A resin laminated film in which a uniaxially stretched film formed from a resin composition blended in a proportion of
Provides _a resin laminated film for shrink labels, characterized in that the film is 5% or less in the unstretched direction at 60°C. Coalescing, (a ₂ ) Ethylene component content 0-5% by weight, butene-
Ethylene, propylene, with a single component content of 8 to 30% by weight and a propylene component content of 92 to 65% by weight.
Butene-1 random copolymer, (a ₃ ) ethylene component content 0-5% by weight, propylene component content 98.5-65% by weight, and butene-1
Ethylene, corresponding to a component content of 0 to 30% by weight;
A mixture of at least two copolymers of at least two of propylene and butene-1. One of the essential components (A) of the resin composition for the base material layer according to the present invention is a propylene copolymer, which is composed of random copolymers (a ₁ ), (a ₂ ) and a mixture of both having the following compositions. (a ₃ ).

[Ink transferability]

The halftone dot area of each color was magnified using a magnifying glass (30x), and the halftone dot reproducibility was visually judged. Halftone dot reproduction rate: 100-75% Good (〇) 75-50% Poor (△) 50-0% Poor (x) [Ink adhesion] Adhesive tape “Cello Tape” manufactured by Nichiban Co., Ltd. (product name) was brought into close contact with the printed surface, quickly peeled off along the printed surface, and the degree of ink removal from the paper surface was visually determined. Ink residual rate: 100-95% Good (〇) 95-80% Slightly poor (△) 80-0% Poor (x) [Continuous offset printing performance] After printing 5000 sheets continuously, the ink pile on the blanket, the blanket The whiteness was compared with the state before printing. In addition, for the printed matter, the halftone dot reproducibility was visually determined by comparing the printed matter immediately after printing started and that after continuous printing. Blanket condition: Same as before printing (〇) Slightly different (△) Largely different (×) [Backing] Offset printing on one side of 500 sheets of film,
When the films were stacked and left horizontally, it was examined whether offset printing ink was attached to the back side of the film. No backing: Good (〇) Slight spotting: Fairly good (〇 ^- ) Number of 100 or less linings: Slightly poor (△) 100 or more linings: Poor (×) Layering 10 anti-blotting films Then, it was cut with a press cutter, and the blocking was peeled off by tension on the cut surface to make a judgment. No blocking (〇) Slight blocking (△) Strong blocking (×) Gloss JIS-T-8142 using a gloss meter manufactured by Suga Test Instruments Co., Ltd.
Measurements were made using the measurement method at a light incident angle of 75°. Surface strength After cutting the film into 20 cm length and 20 cm width, apply cellophane tape (adhesive tape LP-18, trade name, manufactured by Nichiban Co., Ltd.) to about 10 cm of the film by pressing it firmly with your fingers, then quickly peel it off along the film. The surface condition was visually judged. Evaluation criteria: No change in surface condition: 〇 The surface layer was taken off by cellophane tape and partially peeled off: × Label characteristics After cutting the film into 100 mm length and 220 mm width, the longitudinal edges were glued together by Toyo Morton Co., Ltd. Agent “BLS-
A mixture of 2080A and BLS-2080B was used to form a cylindrical shrink label by pasting the ends so that they overlapped by 4 mm. After equipping the bottle with the label, it was placed in an oven at 200°C for 10 seconds to heat shrink the stretched film to obtain a labeled glass bottle.The labeled glass bottle was evaluated using the following method. [Barcode] Presence or absence of printing distortion] Items with no distortion were rated as good (〇), and those with distortion were rated as poor (x). [Uniformity of label edge line at bottle opening] Label edge line was approximately straight. is considered good,
Items that were wavy or had wrinkles were marked as defective (×). [Adhesion to bottle] A labeled glass bottle filled with water was
The temperature change between ℃ and 60℃ was repeated 5 times, and those in which the label did not come off the bottle were evaluated as good (〇), and those in which the label shifted or came off were evaluated as poor. [Heat resistance] When filled with 90℃ hot water, the label softens and
Items that were easily damaged by nails were marked as defective (x). [Drop test] When a labeled bottle filled with a carbonated drink (internal pressure approximately 4.5 kg/cm ² ) is held horizontally and allowed to fall naturally onto a concrete floor from a height of 75 cm, fragments fall within a circle within 1 m from the point of fall. Those with a probability of existence of 90% or more were considered good (〇), those within 60 to 90% were considered fair (△), and those with a probability of less than 60% were considered poor. The evaluation of commercially available 16 oz bottles (containing carbonated drink) is as follows. Polyvinyl chloride label approx. 93% Expanded polystyrene jacket approx. 70% No film approx. 48% Example 2 On the surface of the stretched film obtained in Example 1, a coating agent aqueous solution having the following composition was applied at a solid content of 0.05 g/ After applying it to a thickness of m ² , it was dried at 20°C, offset printing was performed, and both ends were adhered with adhesive to produce a shrink label. (a) 100 parts by weight of water-soluble polyacrylic antistatic polymer "ST-1100" manufactured by Mitsubishi Yuka Fine Co., Ltd. (b) 10 parts by weight of sodium carbonate with an average particle size of 1.2μ. The performance of this Shrink label is shown in Table 1. Examples 3 to 6, Comparative Examples 1 to 3 A three-layer structure was prepared in the same manner as in Example 2, except that the components (A) to (D) of the film, the stretching temperature, and the stretching ratio were changed as shown in Table 1. Shrink labels were manufactured and their performance evaluated. The results are shown in Table 1. In addition, the abbreviations of each component are as follows. (A) Component a ₁ : Ethylene/propylene random copolymer used in Example 1 (melting point 139°C) a ₂ : Ethylene (1.3% by weight), propylene (85.7% by weight), butene-1 (13% by weight) Random copolymer (MFR 3g/10 minutes, melting point 132°C) a ₃ : Homopolypropylene (melting point 164°C) (B) component PB: Homobutene-1 polymer used in Example 1 (C) component LK-30: Mitsubishi Low-density polyethylene “Yukalon LK-30” manufactured by Yuka Co., Ltd. (melting point 106°C) EVA-41H: Comparative example of ethylene/vinyl acetate (16% by weight) copolymer manufactured by Mitsubishi Yuka Co., Ltd. 4 (A) Ethylene・Propylene random copolymer (MFR2.6g/10min, ethylene content 4.2% by weight,
Melting point 139℃) 40 parts by weight (B) Polybutene-1 (MFR18g/10min, melting point 111
℃) 10 parts by weight (C) Low-density polyethylene “Yukalon” manufactured by Mitsubishi Yuka Co., Ltd.
LK-30” (product name, density 0.918g/cc, MI4.0
g/10 minutes, melting point approximately 106°C) 30 parts by weight (D) 20 parts by weight of calcium carbonate with a particle size of 1.2 microns 100 parts by weight of the above components (A), (B), (C) and (b) 1.5 parts by weight of the agent and 0.5 parts by weight of the ultraviolet absorber were added and dry blended for 2 minutes in a super mixer to prepare a resin composition for film molding. This composition was melt-kneaded at 230°C using an extruder, extruded into a sheet from a T-die, cooled to 80°C with a cooling roll, and then reheated to 120°C.
The film was heated to 100°C and stretched 10 times in the transverse direction using a tenter. The surface of this stretched film was subjected to corona discharge treatment, and after cooling to 60°C, the edges were slit and wound up. The obtained uniaxially stretched film (thickness 60 microns) was
After storage for several days, the performance as a Syrinx label was evaluated. The results are shown in Table 1.

【table】

[Table] *Examples other than Example 1 have a primer layer.
** Comparative Example 4 is a single layer film.
*3 Unable to make stretched film

[Brief explanation of drawings]

FIG. 1 is a sectional view of a glass bottle to which a Shrink label is tightly attached, and FIG. 2 is a perspective view thereof. In the figure, 1 is a Syurin label, 2 is a glass bottle,
1b is a barcode.

Claims (1)

[Scope of Claims] 1 25 to 84% by weight of a propylene copolymer (A) selected from the following (a ₁ ) to (a ₃ ), polybutene-1 (B) 1
~30% by weight, 10-40% by weight of olefinic resin (C) with a melting point of 80-110°C, 5-30% by weight of inorganic fine powder (D)
Polypropylene (A ₄ ) 100 to 100, which has a melting point higher than the propylene copolymer (A) by 10°C or more, is added to at least one side of the uniaxially stretched film for the base material layer formed from the resin composition blended in the ratio of 80% by weight
A resin laminated film in which a uniaxially stretched film formed from a resin composition containing 0 to 20% by weight of inorganic fine powder (however, lower than the content of inorganic fine powder in the base layer) is bonded together. The resin laminated film has a dimensional heat shrinkage rate at 120°C in the uniaxial stretching direction of 30 to 60% in the stretching direction and 5% or less in the direction perpendicular to the uniaxial stretching direction. Laminated resin film for syringe labels (a ₁ ) Ethylene-propylene random copolymer with ethylene component content of 2 to 10% by weight, (a ₂ ) Ethylene component content of 0 to 5% by weight, butene-
Ethylene, propylene, with a single component content of 8 to 30% by weight and a propylene component content of 92 to 65% by weight.
Butene-1 random copolymer, (a ₃ ) ethylene component content 0-5% by weight, propylene component content 98.5-65% by weight, and butene-1
Ethylene, corresponding to a component content of 0 to 30% by weight;
A mixture of at least two copolymers of at least two of propylene and butene-1. 2. The laminated resin film for syringe labels according to claim 1, wherein the polypropylene (a ₄ ) is a propylene homopolymer having a melting point of 164 to 167°C.