JP2004017611A - Releasable white laminated film and label using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a releasable white laminated film excellent in whiteness and smoothness and also excellent in releasability. <P>SOLUTION: A white film containing air bubbles has a coating layer releasable from the film formed on at least one surface thereof. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a peelable white laminated film. More specifically, it relates to a peelable white laminated film which is excellent in whiteness and glossiness, and which can be suitably used as a label, emblem, seal, tape, postcard, envelope, envelope, voucher, form, package, or other laminated body. It is.
[0002]
[Prior art]
In general, labels are used for food, medicine, electric / electronic products, medical products, daily goods, etc. for the purpose of quality indication, design indication, quality assurance, expiration date indication, ownership indication, advertising, price tag, name tag, sorting, classification, etc. It is used for various purposes such as office supplies.
[0003]
Above all, adhesive labels are more likely to adhere to many types of adherends and are easier to use than adhesive labels, glue labels, gum labels, screw-on labels, heat seal labels, etc. Is following.
[0004]
The basic configuration of the pressure-sensitive adhesive label is such that a surface substrate, a pressure-sensitive adhesive layer, and a release paper are laminated in this order. Printing is performed on the surface base material as necessary, but when actually used, the release paper is peeled off and the surface base material is attached to the adherend via the adhesive layer.
[0005]
As for the surface substrate, paper, plastic film, cloth, metal and the like are used alone or in combination. Among them, plastic films such as polyester films, polypropylene films, polyvinyl chloride films, and polyethylene films are widely used in terms of water resistance.
[0006]
On the other hand, in recent years, from the viewpoint of global environmental protection, there has been a strong demand for sorting and collecting and recycling plastic waste, and there has been a demand for a label that can be easily peeled off from an adherend after use.
[0007]
However, the conventional adhesive label has a feature that it can be easily attached to an adherend, but has a drawback that it is difficult to peel off the label when it is desired to peel the label from the adherend. When the label is forcibly peeled off, the label is broken, the adherend is damaged, and even if the label is peeled off, the adhesive remains on the surface of the adherend, causing unpleasant stickiness and dirt.
[0008]
On the other hand, there is a demand for a label that cannot be so-called illegally used, in which a label that has been once peeled cannot be used by attaching it again to another adherend.
[0009]
[Problems to be solved by the invention]
The present invention solves the above-described problems, and has excellent whiteness and glossiness, and can be easily peeled off from an adherend after being used for a label or the like, and after being once peeled off. Is intended to provide a peelable white laminated film that cannot be re-adhered.
[0010]
[Means for Solving the Problems]
In order to solve such a problem, the peelable white laminated film of the present invention mainly has the following configuration. That is,
A peelable white laminated film characterized in that a coating layer that can be peeled off from the film is formed on at least one surface of a white film containing bubbles.
[0011]
Further, the label of the present invention mainly has the following configuration. That is,
A label comprising the above-mentioned peelable white laminated film.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The object of the present invention is to achieve the above object, that is, whiteness, excellent in gloss, after being used as a label, it can be easily peeled off when it is desired to peel it off from an adherend, and cannot be re-adhered once it has been peeled off. As a result of intensive studies on the laminated film, it has been found that such a problem can be solved all at once by forming a structure in which a peelable coating layer is formed on at least one surface of a white film containing bubbles.
[0013]
The white film in the present invention is not particularly limited as long as it is a white film made of a thermoplastic resin, but a white film made of polyester is preferably used in terms of mechanical properties, dimensional stability, heat resistance and the like.
[0014]
The polyester preferably used in the present invention is a polymer obtained by condensation polymerization from a diol and a dicarboxylic acid, and dicarboxylic acids are represented by terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid and the like. The diol is represented by ethylene glycol, trimethylene glycol, tetramethylene glycol, cyclohexane dimethanol and the like. Specifically, for example, polyethylene terephthalate, polyethylene-p-oxybenzoate, poly-1,4-cyclohexylene dimethylene terephthalate, polyethylene 2,6-naphthalenedicarboxylate (polyethylene naphthalate) and the like can be used. .
[0015]
Of course, these polyesters may be homopolyesters or copolyesters, and as copolymerization components, for example, diol components such as diethylene glycol, neopentyl glycol, polyalkylene glycol, adipic acid, sebacic acid, and phthalic acid Dicarboxylic acid components such as acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 5-sodium sulfoisophthalic acid can also be used. In the polyester, if necessary, appropriate additives such as heat stabilizers, oxidation stabilizers, organic lubricants, organic fine particles, and fillers may be used in an amount that does not impair the effects of the present invention. , A nucleating agent, a dye, a dispersant, a coupling agent, and the like.
[0016]
As the polyester preferably used in the present invention, polyethylene terephthalate and polyethylene naphthalate are particularly preferable because they are excellent in strength, heat resistance, water resistance, chemical resistance and the like.
[0017]
The white film in the present invention is, for example, a white film obtained by adding inorganic fine particles and fine bubbles to a resin mainly composed of the polyester as a thermoplastic resin.
[0018]
Examples of the inorganic fine particles include, for example, calcium carbonate, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, zinc sulfide, calcium phosphate, silica, alumina, mica, mica titanium, talc, clay, Kaolin, lithium fluoride, calcium fluoride, or the like can be used. These inorganic fine particles may be used alone or in combination of two or more. Further, the inorganic fine particles may be in a form such as porous or hollow porous, and furthermore, within a range not impairing the effects of the present invention, a surface treatment is performed to improve dispersibility in the resin. May be.
[0019]
The average particle diameter of the inorganic fine particles is preferably 0.05 to 3 μm, more preferably 0.07 to 1 μm, from the viewpoint of uniform dispersibility, gloss and smoothness of the film surface.
[0020]
The amount of the inorganic fine particles to be added is not particularly limited, but is preferably 1 to 30% by weight, more preferably 3 to 20% by weight, in view of the whiteness and hiding properties of the film.
[0021]
The white film in the present invention needs to contain bubbles inside. That is, by incorporating bubbles inside, the rigidity of the film is reduced, so-called stiffness of the film is weakened, and the film surface is easily wrinkled when bent. For example, when the label is peeled off from the adherend after being used as a label, fine creases occur on the surface of the white film due to the peeling force applied to the label, and the quality of the label is impaired. It will not be available. In other words, once the label has been peeled off, it can only be discarded, and illegal reuse can be prevented. A white film containing no air bubbles therein is not preferable because it is stiff and hardly wrinkles occur on the surface.
[0022]
In addition, the white film of the present invention contains bubbles inside, especially when printing is performed by the thermal transfer method. It also has the feature that the printability is enhanced and clearer printing can be realized.
[0023]
As a method of containing bubbles, (1) a method of containing a foaming agent and foaming by heating at the time of extrusion or film formation, or foaming by chemical decomposition to form bubbles, (2) a gas or vaporizable at the time of extrusion A method of adding a substance, (3) a method of adding a thermoplastic resin (incompatible resin) that is incompatible with the polyester and uniaxially or biaxially stretching the same to generate fine bubbles, (4) the method described above. Any method may be used, such as a method of adding a large amount of bubble-forming inorganic fine particles instead of the incompatible resin, but it is easy to adjust the amount of bubbles to be contained therein, and more fine and uniform. The method (3) is particularly preferable from the viewpoint of easy formation of bubbles having a size. Specifically, it is preferable that the resin is formed using a resin incompatible with the matrix resin contained in the matrix resin as a core. More specifically, the cross section (in the thickness direction) of the white film is observed with a scanning electron microscope (SEM) or a transmission electron microscope (TEM) in terms of heat insulation, cushioning, and the tendency to generate folds. In this case, the average value of the cross-sectional area of the bubble portion (however, excluding the portion of the incompatible resin serving as the nucleus of bubble generation) is preferably from 1 to 25 μm2, more preferably from 2 to 15 μm2. .
[0024]
The incompatible resin referred to in the present invention is, for example, when the matrix resin is a polyester, a thermoplastic resin other than the polyester, and a thermoplastic resin that is incompatible with the polyester, It is a resin having a large effect of dispersing into particles and forming bubbles in the film by stretching. Specifically, olefin resins such as polyethylene, polypropylene, polybutene, and polymethylpentene, polystyrene resins, polyacrylate resins, polycarbonate resins, polyacrylonitrile resins, polyphenylene sulfide resins, and fluorine-based resins are preferably used. These may be a homopolymer or a copolymer, and may use two or more incompatible resins in combination. Among these, polyolefins such as polypropylene and polymethylpentene having a small critical surface tension are preferable, and polymethylpentene is particularly preferable.
[0025]
The content of the immiscible resin in the white film is not particularly limited, but is preferably 1 to 35% by weight, and more preferably 3 to 20% by weight from the viewpoint of whiteness, glossiness, and apt to wrinkle. Is more preferable.
[0026]
Further, in the present invention, the addition of a dispersant to the polyester and the incompatible resin described above further reduces the dispersion diameter of the incompatible resin, so that bubbles generated by stretching can be made finer. This is more preferable because it can improve the whiteness and film forming property of the film.
[0027]
Examples of the dispersant exhibiting the above effects include olefin polymers or copolymers having a polar group such as a carboxyl group or an epoxy group or a functional group reactive with polyester, polyalkylene glycol, a surfactant, An adhesive resin or the like can be used. Of course, these may be used alone or in combination of two or more. As a method for adding the dispersant, blending that is a mixture with polyester, or copolymerization such as random copolymerization or block copolymerization can be employed. Further, partial copolymerization, which is an intermediate state between the two, may be used. The amount of the dispersant added is preferably 0.05 to 10% by weight, more preferably 0.2 to 5% by weight, from the viewpoint of fineness of air bubbles and whiteness.
[0028]
The white film of the present invention may have a laminated structure of two or more layers in which a white film layer (A) substantially containing no bubbles is formed on at least one surface of the bubble-containing layer (B). Furthermore, a three-layer configuration of A / B / A is also possible. In this case, whiteness, smoothness or glossiness is expressed in the white film layer (A), and cushioning properties and heat insulation properties are expressed in the bubble-containing layer (B), so that the whiteness, glossiness and the like of the white film are improved. It is more preferable because the surface smoothness is improved and wrinkles on the surface are easily formed when the white film is bent.
[0029]
The method of laminating the bubble-containing layer (B) and the white film layer (A) may be any of a method of compounding by coextrusion during melt film formation, or a method of separately forming films and then laminating. The former method is more preferable in terms of cost and cost.
[0030]
In the case of a three-layer structure of A / B / A, the lamination ratio can be set arbitrarily. However, from the viewpoint of balance between smoothness and cushioning property, when the thickness of the entire white film is 100, one side A layer Preferably has a thickness of 0.1 to 10, more preferably 0.5 to 5.
[0031]
The whiteness of the white film of the present invention is preferably 70% or more, and more preferably 80% or more, from the viewpoint of image clarity when printed on the surface. Further, the color tone b value is preferably 2 or less, and more preferably 0 or less. When the color tone b value is 2 or less, the film itself does not become a yellowish color, so that the printed image is less likely to have an old impression, which is preferable. Further, the glossiness is preferably at least 40%, more preferably at least 50%. When the glossiness is 40% or more, unevenness or chipping is less likely to occur in a printed image, and printing failure does not occur.
[0032]
Further, in the present invention, the specific gravity of the film is preferably 0.4 or more and less than 1.3, and more preferably 0.5 or more and 1.1 or less. The specific gravity of the film reflects the content of bubbles formed inside the film, and it can be considered that the smaller the specific gravity, the higher the content of bubbles. By setting the specific gravity of the film in the above range, the film forming property of the film is stabilized, and fine wrinkles can be easily formed on the surface when the obtained film is folded.
[0033]
Although the thickness of the white film of the present invention is not particularly limited, it is usually preferably from 10 to 500 μm, more preferably from about 20 to 300 μm, in view of handleability and rigidity.
[0034]
It is important that the white laminated film of the present invention has a peelable coating layer formed thereon. By forming a peelable coating layer, for example, when an adhesive layer is provided on the surface of the coating layer and used for a label or the like, when the label is peeled, the label is peeled between the white film as the base material and the coating layer. And the label can be easily separated from the adherend. Moreover, once peeled, the white film of the substrate and the coating layer do not adhere again. That is, the label that has been once peeled cannot be pasted again, so that the label cannot be diverted. That is, label reuse and unauthorized use can be prevented.
[0035]
The resin forming the peelable coating layer of the present invention is not particularly limited as long as it is a resin that can be peeled off from the white film serving as the substrate, but in terms of peelability, coating properties, and thickness uniformity, polyvinyl is used. It is preferably composed of at least one selected from alcohol, polyvinylpyrrolidone, ethylene / vinyl alcohol copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, and ethylene / ethyl acrylate copolymer.
[0036]
If necessary, organic lubricants such as flame retardants, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, crystal nucleating agents, pigments, plasticizers, terminal blocking agents, fatty acid esters, waxes, etc. Alternatively, an antifoaming agent such as polysiloxane may be blended.
[0037]
Here, “peelable” means that the white film and the coating layer can be easily peeled off by hand. Specifically, the peel strength between the white film and the coating layer is preferably from 1 mN / cm to 10 N / cm, and more preferably from 5 mN / cm to 5 N / cm.
[0038]
To adjust the peel strength to the above range, by changing the type of coating layer forming resin, changing the thickness of the coating layer, or by adjusting the surface treatment method and treatment level of the coating layer forming surface Achieved. In addition, a wax compound may be added to the white film or the coating layer forming resin to adjust the peel strength, or the coating layer may be formed after applying the wax compound to the surface of the white film. . Further, a configuration in which these are combined may be adopted.
[0039]
As the wax compound added to the resin, for example, an ester compound of an aliphatic carboxylic acid compound and an aliphatic alcohol compound, an amide compound of an aliphatic carboxylic acid compound and an aliphatic amine compound, and the like, preferably wax The compound having a total carbon number of 30 to 120 is preferable. Examples of such compounds include, for example, stearyl stearate, carnauba wax, candelilla wax, rice wax, pentaerythritol full ester, behenyl behenate, partyl myristate, and aliphatic esters such as stearyl triglyceride. Natural wax is preferably used.
[0040]
As the wax compound applied to the film surface, petroleum wax or vegetable wax, and a mixture thereof are preferably used. As the petroleum wax, paraffin wax, microcrystalline wax, oxidized wax and the like can be used. In addition, as the vegetable wax, carnauba wax, candela wax, wood wax, oligury wax, sugar cane wax and the like can be used.
[0041]
The thickness of the peelable coating layer of the present invention can be appropriately set depending on the application, but from the balance between the strength of the coating layer itself and the peel strength, it is preferably 0.01 μm to 50 μm, and 0.05 μm to More preferably, it is 30 μm.
[0042]
The method of forming the peelable coating layer of the present invention is not particularly limited, but does not use a pressure-sensitive adhesive or an adhesive, and the white film serving as a substrate and the coating layer are directly adjacent to each other to form a peeling interface. Preferably, it is formed. By forming a peeling interface directly adjacent without using an adhesive or an adhesive, it is possible to make it impossible to re-attach the once peeled coating layer.
[0043]
As a method for forming the coating layer without using an adhesive or an adhesive, a coating liquid in which the coating layer forming resin is dissolved in water, another organic solvent or a mixed solvent thereof is prepared. Is preferably coated directly on the surface of the white film of the substrate. As the coating method, a conventionally known coating method such as a roll coater, a gravure coater, a reverse coater, a bar coater, a die coater, and a knife coater can be used. In this case, it is preferable that the coating surface of the white film is preliminarily subjected to a pretreatment such as a corona discharge treatment or a plasma treatment.
[0044]
The peelable white laminated film of the present invention can be suitably used as a so-called laminate by laminating with another material. Examples of the material include plain paper, high-quality paper, medium-quality paper, coated paper, art paper, cast-coated paper, resin-impregnated paper, glassine paper, laminated paper, and the like, synthetic paper, nonwoven fabric, fabrics, films, and metals. And the like, and a laminate or the like obtained by combining them. When used by bonding with these other materials, it is preferable to bond the peelable coating layer surface as an adhesive surface with other materials.
[0045]
Next, an example of the method for producing a peelable white laminated film of the present invention will be described, but the present invention is not limited to only such an example.
[0046]
In a composite film forming apparatus having an extruder (A) and an extruder (B), a dry polyester chip and a dry immiscible resin chip as necessary are formed to form a bubble-containing layer (B). A mixture of the incompatible resin in an amount of 1 to 35% by weight is supplied to an extruder (B) heated to 260 to 300 ° C., melted and introduced into a T-die composite die. If necessary, a dispersant may be added to this raw material in an amount of 0.05 to 10% by weight. The addition of the immiscible resin may be performed by drying the master chip which has been previously used. On the other hand, in order to laminate the white film layer (A), polyester chips and a master chip of inorganic fine particles are mixed so that the inorganic fine particles become 1 to 30% by weight, and sufficiently vacuum-dried. If necessary, a 0.01 to 1.5% by weight of a fluorescent whitening agent may be added to this raw material. Next, the dried raw material is supplied to an extruder (A) heated to 260 to 300 ° C., similarly melted and introduced into a T-die composite die, and the polymer of the extruder (A) is extruded (B). The polymer is laminated so as to be on both sides and co-extruded into a sheet to obtain a molten laminated sheet.
[0047]
The melted laminated sheet is tightly cooled and solidified by static electricity on a drum cooled to a surface temperature of 10 to 60 ° C. to produce an unstretched laminated film. The unstretched laminated film is guided to a group of rolls heated to 70 to 120 ° C., stretched 2 to 5 times in a longitudinal direction (longitudinal direction, that is, a direction in which the film advances), and cooled by a group of rolls of 20 to 30 ° C.
[0048]
Subsequently, after a corona discharge treatment is applied to the white film layer (A) side of the film stretched in the longitudinal direction, a coating liquid for forming a peelable coating layer is applied to the treated surface using a gravure coater or the like. The coated film is guided to a tenter while gripping both ends with clips, and stretched 2 to 5 times in a direction (lateral direction) perpendicular to the longitudinal direction in an atmosphere heated to 90 to 150 ° C.
[0049]
The stretching ratio is 2 to 5 times each in the vertical and horizontal directions, and the area ratio (longitudinal stretching ratio × horizontal stretching ratio) is preferably 6 to 20 times from the viewpoint of whiteness and film strength.
[0050]
The biaxially stretched laminated film thus obtained is subjected to heat treatment at 150 to 230 ° C. for 1 to 30 seconds in a tenter in order to impart flatness and dimensional stability, and then gradually cooled down to room temperature. By cooling and winding, the peelable white laminated film of the present invention can be obtained. During the heat treatment step, a 3 to 12% relaxation treatment may be performed in the horizontal or vertical direction as necessary. The biaxial stretching may be either sequential stretching or simultaneous biaxial stretching, and may be re-stretched in either the longitudinal or transverse direction after the biaxial stretching.
[0051]
The peelable white laminated film of the present invention thus obtained has excellent whiteness, glossiness, cushioning properties, heat insulating properties, and easily forms fine wrinkles that can be visually identified when folded. Things. Further, the coating layer formed on the surface of the white film can be easily peeled off.
[0052]
When the peelable white laminated film of the present invention is used as, for example, an adhesive label, necessary characters, designs, information, etc. are printed on the white film surface as a printing surface, and an adhesive is applied to the surface of the coating layer on the opposite side. This is achieved by: The pressure-sensitive adhesive may be appropriately selected from rubber-based, vinyl-based, and acrylic-based adhesives according to the intended use.
[0053]
The label configured as described above is used by being attached to an adherend, but when the label is peeled off after use, it can be easily peeled off between the white film and the coating layer of the base material, Only the label can be separated and collected. In addition, since the label once peeled cannot be adhered again, the label cannot be diverted or reused. Furthermore, since the label is composed of a white film containing bubbles, fine wrinkles are formed on the surface by resistance at the time of peeling, and the quality of the label is impaired. .
[0054]
In other words, the label of the present invention has two major features that a visually identifiable wrinkle is formed on the surface, in addition to a feature that cannot be re-adhered once peeled, so that the label can be misused or reused Can be reliably prevented.
[Method of measuring and evaluating characteristics]
The characteristic values in the examples described later are based on the following evaluation methods and evaluation criteria.
(1) Peel strength
A sample having a width of 2 cm and a length of 12 cm was cut out, a coating layer side was stuck to a 2 mm-thick acrylic plate with a double-sided tape, and a polyester adhesive tape (No. 31B manufactured by Nitto Denko Corporation, (Width 19 mm) was attached, and the upper end of the acrylic plate was suspended on a load cell of a Tensilon tensile tester (UTMIII, Toyo Sokki Co., Ltd.). Next, a strip-shaped lead paper is stuck on the upper end of the adhesive tape, and once it is gripped by the lower chuck and pulled downward (180 degrees) at a crosshead speed of 300 mm / min to peel off the interlayer between the white film and the release layer. The force was measured. The peeling strength (N / cm) was calculated from the average peeling force T (N) having a peeling length of 50 mm or more excluding the rising part of the SS curve by the following formula.
[0055]
Peel strength (N / cm) = T / W
Here, T (N): average peeling force, W (cm): sample width
(2) Whiteness
Using a spectroscopic color difference meter SE-2000 (manufactured by Nippon Denshoku Industries Co., Ltd.), under the optical conditions in accordance with JIS Z-8722, the color of the white laminated film is measured from the white film side (the surface opposite to the coating layer). The X, Y, and Z values, which are tristimulus values, were measured, and the whiteness was calculated by the following equation.
[0056]
Whiteness (%) = 4 × 0.847 × Z value−3 × Y value
(3) Color b value
The measurement was performed under the apparatus and optical conditions described in the above section (2), and determined in accordance with JIS Z 8730.
(4) glossiness
Using a digital variable-angle gloss meter UGV-5B (manufactured by Suga Test Instruments Co., Ltd.), the measurement was performed from the white film side according to JIS Z8741. The measurement conditions were an incident angle = 60 ° and a light receiving angle = 60 °.
(5) Specific gravity
A sample obtained by cutting the film into a size of 50 mm × 60 mm was measured by a float-sink method using a high-precision electronic hydrometer SD-120L (manufactured by Mirage Trading Co., Ltd.). In the measurement, correction was made in advance by the room temperature at the time of measurement.
[0057]
【Example】
Example 1
In a composite film forming apparatus having an extruder (A) and an extruder (B), an anatase having an average particle diameter of 0.2 μm is formed on a polyethylene terephthalate (hereinafter abbreviated as PET) chip to form a white film layer (A). The raw material to which 7% by weight of the titanium oxide fine particles were added was dried at 180 ° C. for 3 hours, supplied to the extruder (A) side, melted at 285 ° C. by a conventional method, and introduced into a T-die composite die.
[0058]
On the other hand, in order to form the bubble-containing layer (B), the above-mentioned PET chip was added with 10% by weight of polymethylpentene and 1% by weight of polyethylene glycol having a molecular weight of 4000 as a dispersant, and dried at 180 ° C. for 3 hours. The mixture was supplied to the extruder (B), melted at 285 ° C. by a conventional method, and similarly introduced into a T-die composite die.
[0059]
Next, the white film layer (A) was merged so as to be laminated on both surface layers of the bubble-containing layer (B) in the die, and then co-extruded into a sheet to obtain a melt laminated sheet. The molten laminated sheet was tightly cooled and solidified by an electrostatic charge method on a cooling drum maintained at a surface temperature of 25 ° C. to obtain an unstretched laminated film.
[0060]
Subsequently, the unstretched laminated film was stretched 3.2 times in the longitudinal direction (longitudinal direction) using a group of rolls heated to 95 ° C., and cooled by a group of rolls at 25 ° C. to obtain a uniaxially stretched film. Subsequently, the uniaxially stretched film is subjected to a corona discharge treatment in air, and a polyvinyl alcohol ("Gohsenol" (registered trademark) GH-17, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) as a peelable coating layer on the treated surface. Was applied by a bar coating method using a metering bar.
[0061]
The coated uniaxially stretched film is guided into a preheating zone in a tenter while gripping both ends of the film with clips, preheated and dried at 110 ° C., and then continuously continuously heated at 125 ° C. in a direction perpendicular to the longitudinal direction (lateral direction). Stretched 3.3 times. Subsequently, after a heat treatment at 220 ° C. in a heat treatment zone in the tenter, the film is uniformly cooled, and then rolled up. The white film layer (A) has a thickness of 5 μm on one side and the bubble-containing layer (B) has a thickness of 90 μm. A peelable white laminated film in which a coating layer having a thickness of 1 μm was provided on a 100 μm white film was obtained.
[0062]
The obtained peelable white laminated film had a whiteness of 82%, a color tone b value of 1.0, a glossiness of 71%, and a specific gravity of 0.82. When the peel strength of the coating layer was measured, the peel strength was 1.2 N / cm.
(Preparation of adhesive label)
An adhesive composed of an ethylene / vinyl acetate copolymer was applied to the surface of the coating layer of the white laminated film to prepare an adhesive label having a size of 4 cm × 5 cm. After sticking the pressure-sensitive adhesive label on a cardboard having a thickness of 0.4 mm, when the label was peeled off by hand, it could be peeled between the white film and the coating layer of the label, and the surface of the peeled label was Had fine wrinkles. Further, even if the peeled label was again put on the peeling surface of the cardboard, it could not be adhered.
Example 2
A peelable white laminated film was obtained in the same manner as in Example 1 except that polyvinylpyrrolidone (PX-K90P, manufactured by Nippon Shokubai Co., Ltd.) was used as the peelable coating layer. When the peel strength of the coating layer of the obtained peelable white laminated film was measured, the peel strength was 1.0 N / cm.
(Preparation of adhesive label)
An adhesive label was produced in the same manner as in Example 1. After attaching the pressure-sensitive adhesive label to a cardboard having a thickness of 0.4 mm, the label was peeled off by hand, and the label could be peeled off between the white film and the coating layer of the label. Fine wrinkles were formed on the surface of the peeled label. Further, even if the peeled label was again put on the peeling surface of the cardboard, it could not be adhered.
Example 3
In Example 1, the thickness was changed in the same manner as in Example 1 except that an ethylene / vinyl acetate copolymer ("Exeval" (registered trademark) AQ-4105 manufactured by Kuraray Co., Ltd.) was used as the peelable coating layer. A peelable white laminated film provided with a coating layer having a thickness of 1 μm was obtained.
[0063]
When the peel strength of the coating layer of the obtained peelable white laminated film was measured, the peel strength was 80 mN / cm.
(Preparation of adhesive label)
An adhesive label was produced in the same manner as in Example 1. After sticking the pressure-sensitive adhesive label on a cardboard having a thickness of 0.4 mm, the label was peeled off by hand. As a result, the label could be peeled off cleanly between the white film and the coating layer. Fine wrinkles were formed on the surface of the peeled label. Further, even if the peeled label was again put on the peeling surface of the cardboard, it could not be adhered.
Example 4
In the same manner as in Example 1, except that a 3% aqueous coating solution of wax (KEK-T, manufactured by Koei Chemical Co., Ltd.) was used in place of the peelable coating layer, the thickness on one surface was changed in the same manner as in Example 1. A white laminated film provided with a 0.07 μm wax layer was wound up.
[0064]
Next, on the wax layer of the obtained white laminated film, a 10% aqueous coating solution of polyvinyl alcohol (“Gosenol” (registered trademark) GH-17, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used as a peelable coating layer. It was applied and dried using a metaling bar to produce a peelable white laminated film provided with a coating layer having a thickness of 1 μm.
[0065]
When the peel strength of the coating layer of the obtained peelable white laminated film was measured, the peel strength was 20 mN / cm.
(Preparation of adhesive label)
An adhesive label was produced in the same manner as in Example 1. After sticking the pressure-sensitive adhesive label on a cardboard having a thickness of 0.4 mm, the label was peeled off by hand. As a result, the label could be peeled off cleanly between the white film and the coating layer. Fine wrinkles were formed on the surface of the peeled label. Further, even if the peeled label was again put on the peeling surface of the cardboard, it could not be adhered.
Example 5
In Example 3, a 3 μm thick film was formed in the same manner as in Example 3 except that ethylene / vinyl alcohol (“EVAL” (registered trademark) L-101 manufactured by Kuraray Co., Ltd.) was used as the peelable coating layer. A peelable white laminated film provided with a coating layer was produced.
[0066]
When the peel strength of the coating layer of the obtained peelable white laminated film was measured, the peel strength was 6 mN / cm.
(Preparation of adhesive label)
An adhesive label was produced in the same manner as in Example 1. After attaching the pressure-sensitive adhesive label to a cardboard having a thickness of 0.4 mm, the label was peeled off by hand, and the label could be peeled off between the white film and the coating layer of the label. Fine wrinkles were formed on the surface of the peeled label. Further, even if the peeled label was again put on the peeling surface of the cardboard, it could not be adhered.
Comparative Example 1
In Example 1, only the white laminated film was wound without forming the coating layer.
(Preparation of adhesive label)
An adhesive comprising an ethylene / vinyl acetate copolymer was applied to one surface of the white laminated film to prepare an adhesive label having a size of 4 cm × 5 cm. After sticking the pressure-sensitive adhesive label on a cardboard having a thickness of 0.4 mm and peeling the label by hand, the pressure-sensitive adhesive layer of the label was strongly adhered to the cardboard, the surface of the cardboard was broken, and only the label was removed. Could not be removed.
Comparative Example 2
In Example 1, only the white laminated film was wound without forming the coating layer.
(Preparation of adhesive label)
An adhesive comprising an ethylene / vinyl acetate copolymer was applied to one surface of the white laminated film to prepare an adhesive label having a size of 4 cm × 5 cm. After sticking the pressure-sensitive adhesive label to a clean aluminum plate having a surface of 1 mm in thickness, the label was peeled off by hand, and the label and the pressure-sensitive adhesive layer were peeled off from the aluminum plate while being integrated. When the peeled label was again attached to the aluminum plate, it could be re-adhered.
[0067]
As described above, since the peelable white laminated films of Examples 1 to 4 according to the present invention are formed with a peelable coating layer, they can be peeled between the white film and the coating layer of the base material. it can. When the film is used for an adhesive label, only the label portion can be easily separated and collected from the adherend. Fine wrinkles that could be visually recognized were formed on the surface of the peeled label. Further, the label once peeled off could not be adhered to the peeled surface again. In contrast, Comparative Example 1 could not be separated from the adherend, and when forcibly peeled off, the surface of the adherend was broken. In Comparative Example 2, the label and the pressure-sensitive adhesive layer were integrally peeled off from the adherend, and only the label could not be separated. Once the label was peeled off, it could be adhered to the aluminum plate again.
[0068]
【The invention's effect】
The peelable white laminated film of the present invention is formed by forming a coating layer that can be peeled off from the film on at least one side of the white film containing bubbles, so that the whiteness and the gloss of the base material are excellent. It can be easily peeled between the film and the coating layer. Therefore, when the film is used for a label or the like, a clear printed image can be formed on the label surface, and the used label can be easily peeled off from the adherend, and the label can be separated and collected. . Moreover, the labels that have been once peeled cannot be re-adhered. Furthermore, fine wrinkles that can be visually identified are formed on the surface of the peeled label, and the quality of the label is impaired. Therefore, it is obvious at a glance that the label has been peeled. That is, the label using the peelable white laminated film of the present invention cannot be diverted or reused once peeled off. That is, improper use of the label can be reliably prevented.
[0069]
The peelable white film of the present invention having the above effects can be widely applied not only to labels but also to various uses such as patches, seals, tapes, postcards, envelopes, slips, forms, and packaging materials.

Claims (7)

A peelable white laminated film, wherein a coating layer that can be peeled off from the film is formed on at least one surface of a white film containing bubbles. The coating layer is at least selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, ethylene / vinyl alcohol copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer. The peelable white laminated film according to claim 1, comprising one kind. The peelable white laminated film according to claim 1 or 2, wherein the peel strength between the white film and the coating layer is 1 mN / cm to 10 N / cm. The peelable white laminated film according to any one of claims 1 to 3, wherein the white film has a whiteness of 70% or more, a color tone b value of 2 or less, and a glossiness of 40% or more. . The peelable white laminated film according to any one of claims 1 to 4, wherein the specific gravity of the white film is 0.4 to 1.3. The peelable white laminated film according to any one of claims 1 to 5, wherein the white film is made of a polyester resin, and contains a thermoplastic resin incompatible with the polyester resin. . A label comprising the peelable white laminated film according to any one of claims 1 to 6.