JPH09330029A - Film for stretchable label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film for stretchable labels which are mounted, at columnar or prismatic objects, are not damaged by sterilization with hot water and have excellent heat resistance, scratching resistance and printing effect. SOLUTION: This film for the stretchable labels contains at least 95wt.% of straight chain low-density polyethylene(LDPE) of 0.905 to 0.940g/cm<3> in density polymerized by using a single sight system catalyst or is composed of 55 to 98wt.% straight chain LDPE of 0.895 to 0.940g/cm<3> in density polymerized by using the catalyst described above and 2 to 45wt.% polyolefin resin. The film having 30 to 150μm thickness has a double refractive index of 0.001 to 0.005 when the refractive index is measured by using a wavelength of 590nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a label attached to the periphery of a cylindrical or prismatic bottle or the like, and more specifically, the self-stretchability of a film is used for labeling, and the label is heat resistant. Belongs to a stretch label film that is not easily scratched on the surface and has excellent scratch resistance and printing effect.

[0002]

A stretch label made of a film having a pattern layer and having excellent self-stretchability can be adhered / followed according to subtle deformation of the container after being attached to a plastic container or a glass container. There are features.
As a film for stretch labels, an ethylene / vinyl acetate copolymer film containing 3 to 10 mol% of vinyl acetate has been conventionally used. However, the film of ethylene / vinyl acetate copolymer has mechanical strength such as tear strength, filling of hot solution, especially sterilization treatment with hot water at 80 to 100 ° C after filling such as carbonated juice (hereinafter referred to as pasteurizer treatment). If it is applied), the label loses its elasticity and may fall off,
There have been problems such as wrinkles due to lack of heat resistance, and inferior scratch resistance and oil resistance in which the surface is easily scratched.

The present invention not only improves the mechanical strength, heat resistance, scratch resistance that scratches the surface are difficult and oil resistance, which are the drawbacks of the ethylene-vinyl acetate copolymer film as a stretch label. An object of the present invention is to provide a method for producing a stretch label film having excellent chemical resistance, printing effect, and wrinkles that do not occur after the pasteurizer treatment with hot water after filling of carbonated juice with excellent stretchability and adhesion. Is.

[0004]

In order to solve the above problems, the present invention provides a linear low density polyethylene simple substance having a density of 0.905 to 0.940 g / cm ³ polymerized by using a single site catalyst. A thermoplastic composition containing at least 95% by weight, or 55 to 98% by weight of a linear low-density polyethylene having a density of 0.880 to 0.940 g / cm ³ polymerized using a single-site catalyst. Thickness 30 composed of 2 to 45% by weight of polyolefin resin
The film of 150 μm to 150 μm is a film for stretch label having a “birefringence” of 0.001 to 0.005 measured using a wavelength of 590 nm. The film is a stretch label film containing a lubricant, an anti-blocking agent, an antioxidant and / or an antistatic agent.

The "birefringence index" in the present invention is as follows. That is, the oriented polymer film shown in FIG.
When a light ray 100 is incident and propagates inside the film as shown in FIG. 2, the incident light is divided into light having vibrating planes orthogonal to each other, that is, an ordinary ray 101 and an extraordinary ray 102 (this is a birefringence phenomenon). Called). After passing through the sample film, the two kinds of light generate a phase difference δ according to the degree of orientation of the sample film. A numerical value obtained by converting the phase difference δ into a deviation in the traveling direction of light is called retardation R. Then, the birefringence Δn of the sample is calculated by the following equation (1). Δn = R / t (1) However, t: thickness of sample film R: retardation The magnitude of the molecular orientation of the film can be determined by the magnitude of this birefringence Δn.

The measurement of retardation R is shown in FIG.
Optical system K of KOBRA-21ADH and sample film 10
The light receiving unit 106 captures the measurement light of the ordinary ray 101 and the extraordinary ray 102 that have passed through and, and digitizes the intensity thereof. When the optical axis is rotated while the polarizer 107 and the analyzer 108 maintain the parallel Nicols 109, the transmitted light intensity generally changes depending on the rotation angle as shown in the following relational expression (2). I (θ) = I ₀ {α ² cos ⁴ (θ−φ) + sin ⁴ (θ−φ) + 1/2 cosδ ・ α ・ sin ² 2 (θ−φ)} ・ ・ ・ ・ ・ (2) , Θ: Rotation angle of polarizer and analyzer φ: Main refractive index direction I (θ): Intensity of transmitted light I ₀ : Maximum amount of transmitted light α: Amplitude transmittance ratio between I direction and its orthogonal direction By the above formula (2) The phase difference δ is obtained, and the retardation value R is obtained from the following relational expression (3) and the above relational expression (1),
Then, the birefringence R can be calculated as Δn. R [nm] = (δ / 2π) λ ··· (3) where λ: wavelength of measurement light (590 nm)

[0007]

2. Description of the Related Art A conventional label attached to a container is a tubular label made of a stretched film such as polystyrene or polyvinyl chloride provided with a pattern layer on the front surface of the film or the back surface of the transparent film, and heat-shrinked to adhere. Shrink label, glued label to be glued and attached to the paper of the label laminated with paper or film or aluminum foil and paper provided with a picture layer, or a method of sticking the above label with an adhesive,
There are stretch labels and the like in which a tubular label made of a plastic film having a self-stretch property provided with a picture layer is stretched and inserted into a container and adhered to the container.

Among the above, the stretch label not only has the feature of being flexible and capable of closely adhering to the subtle deformation of the container even after being attached to the plastic container, and is also excellent in water resistance and as a container. Is only in close contact (in the present specification, a state in which, when peeled, there is no broken deposit on either the container or the label and peeling is possible at the interface is referred to as close contact). . Therefore, it can be used for drinking water containers such as glass, polyethylene terephthalate (hereinafter referred to as PET), polyvinyl chloride, etc., and can separate the fragments and labels after crushing the recovery container by the difference in specific gravity, and for mounting. Since it does not require heat or a special adhesive, it is often used for labels on recycling containers.

As a conventional stretch label, a film of an ethylene / vinyl acetate copolymer combination containing vinyl acetate in an amount of 3 to 10 mol% has been mainly used. However,
This film of ethylene-vinyl acetate copolymer has poor mechanical strength such as tensile strength and tear strength, and it expands and contracts the label when it is filled with hot liquid, subjected to pasteurizer treatment after filling, or cooled. Loss due to lack of heat resistance, such as lack of heat resistance, which makes it impossible to follow the shape change of the container and falling off, and wrinkles, and problems such as scratch resistance and oil resistance that easily scratch the surface. was there.

When the content of vinyl acetate is increased in order to increase the stretchability of the ethylene / vinyl acetate copolymer, not only the heat resistance is further lowered, but also the stickiness tends to occur, and handling such as film winding. There was a problem that it interfered with. To solve this problem, increasing the amount of lubricant added reduces the adhesion of the printing ink or repels the printing ink, which not only reduces the printing effect, but also forms a stretch label from the film. In some cases, the bonding state during processing into a cylindrical shape varies.

On the other hand, although low-density polyethylene (hereinafter referred to as LDPE), which is a homopolymer of ethylene having low tackiness, may be used, it is one that can comprehensively solve stretchability, slipperiness, and printability. There wasn't. Also, the resin used to make the film has a density of 0.905 to 0.9.
A technique for a stretch label film comprising 50% by weight or more of linear low-density polyethylene having a Vicat softening point of 80 ° C. or more at 40 g / cm ³ is also disclosed (Japanese Patent Laid-Open No. 7-29200).
(See Japanese Patent Publication No. 234638). However, since a film made of linear low-density polyethylene has a stress 0 strain in a hysteresis curve (hereinafter referred to as an S-S curve) of close to 10%, it does not have sufficient stretchability, and the adhesiveness after label insertion and There was a problem that it was inferior in heat-slip resistance.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In order to achieve the above object, the present invention provides a linear low density polyethylene simple substance polymerized using a single site catalyst and having a density of 0.905 to 0.940 g / cm ^3. A resin composition containing at least 95% by weight, or 55 to 98% by weight of a linear low-density polyethylene having a density of 0.880 to 0.940 g / cm ³ polymerized using a single-site catalyst, and a polyolefin resin Has a thickness of 30 to 150 μm
It is a film of m. And the film is 590n
Birefringence measured using the wavelength of m is 0.001 to
It is a film for stretch labels having a thickness of 0.005.
Further, the film is a lubricant, an anti-blocking agent,
A stretch label film containing an antioxidant and / or an antistatic agent.

The film of the present invention is characterized by having a molecular orientation in a fixed direction and being less likely to wrinkle due to shrinkage by hot water even when subjected to a pasteurizer treatment.

The single-site catalyst is characterized in that the active sites during the polymerization reaction are equivalent and uniform. This single-site metallocene catalyst is a metallocene-based transition metal compound and an organoaluminum compound or a boron compound, and may be used while being supported by an inorganic substance.

The single-site type transition metal compound is a transition metal selected from Group IVA of the periodic table of elements, that is, titanium, zirconium, hafnium, cyclopentadienyl group, substituted cyclopentadienyl group, indenyl group, substituted indenyl group. 1 to 2 groups, tetrahydroindenyl groups, substituted tetrahydroindenyl groups, fluorenyl groups, or substituted fluorenyl groups are bonded, or two of these groups are covalently crosslinked In addition, hydrogen atom, oxygen atom, nitrogen atom, silicon atom, halogen atom, alkyl group, alkoxy group, aryl group, acetylacetonal group, carbonyl group, substituents including Lewis base, coordination of unsaturated hydrocarbon, etc. It has a child.

Examples of the organoaluminum compound include alkylaluminum, and chain or cyclic alumoxane. Examples of the alkylaluminum include triethylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, dimethylaluminum fluoride, diisobutylaluminum hydride, diethylaluminum hydride, and ethylaluminum sesquichloride.

The chain or cyclic aluminoxane is produced by contacting alkylaluminum and water. For example, it can be obtained by adding water after adding alkyl aluminum at the time of polymerization, or by reacting water of crystallization of a complex salt or water of adsorption of an organic / inorganic compound with alkyl aluminum.

Examples of the inorganic material carrying the single-site catalyst include silica gel, zeolite, diatomaceous earth and the like. Examples of the polymerization method include bulk polymerization, solution polymerization, suspension polymerization, and gas phase polymerization. These polymerizations may be of a batch type or a continuous type. The polymerization temperature, pressure and time conditions are -100 to 25 ° C and 1 to 50 kg / c.
m ² , 0.08 to 10 hours.

The linear low-density polyethylene polymerized using the single-site catalyst of the present invention has a density of 0.90.
5 to 0.940 g / cm ³ is preferable, and if the density is higher than the above range, the stretchability is insufficient, and if it is low, the film has tackiness and is difficult to wind, and wrinkles occur when the label is inserted into and attached to the container. More likely to occur. However, even if the density is 0.905 or less, tackiness can be prevented by including another polyolefin resin in an amount of 2 to 45% as described later.

When the thickness of the film is 30 μm or less, wrinkles are likely to occur during printing and label processing for joining and cutting into a tubular shape. When it is 150 μm or more,
Not only is it wasteful of resources, but also the rigidity becomes strong, the stretchability becomes poor, and the insertion and mounting work may be hindered.

The polyethylene used for the stretch label film of the present invention is produced by mixing linear low density polyethylene polymerized using a single site catalyst with another polyolefin resin in the range of 2 to 45%. Can be membrane. At this time, the density of the linear low-density polyethylene produced using the single-site catalyst is not always 0.
It is not necessary to be 905 g / cm ³ or more, 0.880 g
/ Cm ³ order may be of, but mixed with other polyolefin resins density, 0.905～0.970G
/ Cm ³ is sufficient. Then, the above-mentioned birefringence is 0.
The type does not matter as long as it is in the range of 001 to 0.005.

In the present invention, the polyolefin resin mixed with the linear low-density polyethylene polymerized using the single-site catalyst is a linear low-density polyethylene polymerized using the multi-site catalyst, Density polyethylene, LDPE, high density polyethylene, ethylene
Vinyl acetate copolymer, ethylene / acrylic acid copolymer,
Examples include ethylene / acrylic acid ester copolymers, polypropylene, and ionomers. By mixing these resins, when the film density exceeds 0.970 g / cm ³ , even after the label is peeled from the container after being adhered and used as a label on a container such as glass, PET or polyvinyl chloride. However, it becomes difficult to separate the container from the crushed resin due to the difference in density. Therefore, it is preferable to set the density of the film smaller than that of the container.

The stretch label film may be composed of two or three layers mainly composed of linear low-density polyethylene polymerized by using the above single site catalyst, and if necessary, adhesiveness between the layers may be improved. A resin layer can also be provided. A linear low density polyethylene polymerized by using the above single-site catalyst with a different density (for example, mainly the intermediate layer with a particularly low density, and the higher density with a thinner layer on the surface). It may be used for the layer, and may be a linear polyethylene comprising an ethylene / α-olefin copolymer, LDPE, an ethylene / vinyl acetate copolymer, an ethylene / acrylic acid copolymer, an ethylene / acrylic acid ester copolymer, An appropriate blend of an ionomer, polypropylene and the like can be used.

The stretch label film is a liquid paraffin, a synthetic paraffin, an aliphatic hydrocarbon such as microcrystalline wax, an ester of a straight chain alcohol and stearic acid, in order to provide lubricity as necessary.
Lubricants and anti-blocking agents such as higher fatty acid amides, nonionic surfactants, anionic surfactants, antistatic agents such as amphoteric surfactants and / or metal compounds that can be used for polyolefin resins, epoxy compounds A stabilizer composed of a nitrogen compound, a phosphorus compound, a sulfur compound, a phenol compound or the like can be appropriately selected and added. Coloring with an inorganic or organic pigment can also be performed.

The stretch label film of the present invention comprises:
An unstretched film 1 having a thickness of 30 to 150 μm is prepared by a usual film forming method using a T-die and a circular die. For example, the resin melt-extruded from the T die 11 shown in FIG. 3 is brought into close contact with the cooling roll 13 in the air chamber 12, and is further drawn by the nip roll 14 and the subsequent cooling roll 13 to form the unstretched film 1. Then, the unstretched film 1 is heated to 60 to 90 ° C. by the heater 19 in the preheating section 16 and the stretching section 17, as shown in FIG. Then, the peripheral speed of the roll 18 in the cooling unit is 1.05 to 1.15 times the supply speed of the unstretched film 1, and the film 1 is stretched while being heated in the stretching unit 17 and is cooled to room temperature in the cooling unit 18. The film is cooled and fixed to prepare a stretched film. Further, the stretch label film 10 in which the surface of the film which is not in contact with the original cooling roll 13 has been subjected to the treatment for easy adhesion of the printing ink by corona discharge is wound.

The thickness 30 to 15 thus prepared
The film for stretch labels has a birefringence of 0.001 to 0.005 measured using a wavelength of 590 nm of a 0 μm film. Then, the above film was formed to have a width of 15 mm in a direction orthogonal to the film forming direction.
A strip-shaped test piece P shown in Fig. 2 is chucked at 100 mm intervals and stretched and deformed in the XY direction at a rate of 300 mm / min. The stress 0 strain d obtained by measuring the following SS curve is 25% or less. %, And the permanent set e does not exceed 1.5%.

When the birefringence is less than 0.001,
The heat shrinkage in the longitudinal direction is insufficient, and if it exceeds 0.005, the heat shrinkage becomes large, which causes wrinkles and a deformation of the pattern layer in the pasteurizer treatment as described later.

The stretching of the film of the present invention is not limited to the longitudinal uniaxial stretching as in the above-mentioned method, but a circular die or a
Even with a T-die, it is possible to stretch in the transverse direction by changing the blow ratio or by using a tenter. Therefore, the labeler can be stretched in any of longitudinal and lateral directions depending on the convenience of use.

The heat setting temperature of the film of the present invention can be arbitrarily selected between the glass transition temperature Tg and the melting point Tm,
From the relationship between the stretchability of the film and the heat resistant temperature, 60 to 9
0 ° C. is preferred.

The heat shrinkage in the longitudinal direction of the stretch label film of the present invention is 0.1% at 60 ° C. and -1 at 70 ° C.
%, And −2% at 80 ° C. is preferable, and in the transverse direction, the physical properties in which stretchability is more important than heat shrinkage, and the heat shrinkage is not particularly limited. When the heat shrinkage in the vertical direction is small, there is a problem that when the container on which the label is mounted is heat-treated, the expanded label largely changes when returning to room temperature and wrinkles occur. Further, if the thermal shrinkage in the longitudinal direction is larger than the above, the label shrinks more than the container that deforms due to the thermal expansion coefficient at the heat treatment temperature, so that the label wrinkles when the container returns to room temperature, and in extreme cases, characters , The pattern may be transformed.

In these films, the surface on which the pattern layer is provided is subjected to an easy-adhesion treatment such as corona discharge treatment, and if desired, gravure printing, flexographic printing, silk-screen printing, or sheet-fed printing. Layers are provided.
Printing is usually carried out by so-called back printing, in which the picture layer can be seen as glossy through a transparent film and the picture layer of the label can be protected by the film. It is also possible to perform printing on an untreated film that has not been subjected to the easy-adhesion treatment, or surface printing (for example, additional printing such as quantity or price).

The printing ink for providing the pattern layer may be a usual printing ink for polyolefin film (in the case of back printing, gloss is not required), an inorganic or organic pigment is used as a colorant, and a binder having high elasticity is used. Composed of. The binder is appropriately selected from polyamides, polyesters, polyurethanes, cyclized rubbers and the like which can be dissolved in a usual solvent for gravure ink. And for these inks,
It is preferable to add a binder such as nitrification cotton, a lubricant, and an anti-blocking agent, which imparts lubricity and improves heat resistance in order to prevent blocking.

However, the use of an excessive amount of fine particles of an antiblocking agent such as silica, talc, calcium carbonate, etc. roughens the printed surface and, when wound, causes an embossing action on the non-printed surface of the film. It should be noted that it may change the gloss. Also,
If a large amount of a lubricant such as higher fatty acid, higher fatty acid amide or silicone is used, the printing effect is deteriorated by inhibiting the adhesion of the printing ink or repelling the ink, so the addition amount should be 0.5% by weight or less. Is preferred.

The stretch label film of the present invention comprises:
Usually, as shown in FIGS. 6 (A), (B) and (C), the pattern layer 2 is provided by back printing on the corona-treated surface of the film 10 in the direction in which the film forming direction M is upside down, and the pattern layer 2 is formed on the inner surface. In this state, the end of the non-printed surface is subjected to corona discharge treatment, the adhesive 3 is applied and the front and back of the film are bonded to form the joint 4, or the front and back are heat-sealed without the adhesive. Then, the stretch label 5 having a tubular shape is formed. Further, the circumference of the stretch label is designed to have a length in the lateral direction of the film (direction orthogonal to the film forming direction) so as to be 99 to 90% of the outer circumference of the container 6 to be mounted shown in FIG. Also, the top and bottom of the stretch label, that is, the direction of film flow is cut to the desired length of the label.

The label 5 formed in a tubular shape is shown in FIG.
As shown in (A), (B), (C) and (D), the label loading machine stretches the stretch label 1 in the stretching direction 7.
After being stretched by 5 to 30% and inserted into the container 6 in the unfolded state, it is contracted when the stretching is removed to obtain the container 61 in which the label 5 is adhered and attached to the outer surface of the container 6.

Further, as shown in FIG. 8, the container 61 fitted with the stretch label 5 is filled with the contents 8 and then heated with hot water 9
Is sprayed to heat the contents 8 to about 80 ° C. for sterilization and water cooling for sterilization cooling to obtain a container 63. At this time PET
Plastic containers made of polyvinyl chloride or polyvinyl chloride may be deformed by temperature. Therefore, it is required that the label attached to the surface of the container can follow the deformation.

The stretch label film of the present invention comprises:
The birefringence measured using a wavelength of 590 nm is 0.0
It is formed by uniformly stretching in the machine direction of the film so as to be 01 to 0.005. A film having a birefringence of 0.001 or less has an insufficient degree of stretching and has a heat shrinkage of 6 in the machine direction.
The shrinkage is smaller than 0.1% at 0 ° C, 1% at 70 ° C, and 2% at 80 ° C. A stretch label made of such a film has a problem that when a label-attached container is subjected to a pasteurizer treatment, the label that has expanded due to the temperature is greatly changed when it returns to room temperature, causing wrinkles. When the birefringence exceeds 0.005, the thermal shrinkage in the vertical direction becomes larger than the above, and the shrinkage after the pasteurizer treatment is large, the label is deformed, the pattern layer is deformed, and the container is expanded. Cause wrinkles when cooled.

[0038]

[Experimental example]

(Experimental Example 1) A composition having the composition shown in Table 1 was added with 0.2% of silica as an anti-blocking agent and 0.05% of stearic acid amide as a lubricant, and a film was formed with a T-die shown in FIG. And 1.0 times, 1.10 times, and 1.
A 20-fold longitudinal uniaxial stretching was performed to prepare samples of Examples and Comparative Examples. (Resin used in Experimental Examples) * 1 SPE1: Linear low-density polyethylene having a density of 0.895 g / cm ³ polymerized using a single-site catalyst * 2 SPE2: Single-site catalyst used polymerized linear low density density 0.920 g / cm ³ polyethylene * 3 S · PE3: linear low density single site catalyst density which is polymerized using the 0.925 g / cm ³ polyethylene * 4 M · PE4: multisite systems linear low density of the catalyst is polymerized density using the 0.920 g / cm ³ polyethylene * 5 MDPE5: density is density polyethylene above in 0.935 g / cm ³ As shown in FIG. 3, the resin composition is extruded through a T-die 11 at 230 ° C. by a normal film-forming method so that the resin composition is brought into close contact with a mirror-cooling roll 13 having a thickness of 60 ° C. in an air chamber 12 and is then wrapped around. Degree the in the 1.02 times the cooling roll ratio 110μm
The unstretched film 1 is prepared. Then, as shown in FIG. 4, the pre-stretched portion 16 and the stretched portion 17 are formed on the unstretched film 1.
Then, the heater 19 is also used to heat at 60 to 80 ° C. Further, the peripheral speed of the roll in the cooling section is set to 1.05 to 1.20 times the supply speed of the unstretched film 1 (stretch ratio 1.05).
˜1.20), the unstretched film 1 is stretched in the stretching unit 17, cooled and fixed at room temperature in the cooling unit 18, and a longitudinal uniaxially stretched film is prepared. Further, a stretch label film 10 of an experimental example was formed in which the surface of the film that did not come into contact with the first cooling roll at the time of film formation was subjected to an easy adhesion treatment of the printing ink by corona discharge. (Below margin)

[0039]

[Table 1]

With respect to the samples (Experiment Nos. 1 to 20) of the present invention and the comparative examples prepared in the experimental example, the following methods were used to expand / contract, heat-slip resistance (dynamic friction coefficient), thermal shrinkage ratio, birefringence index and Table 2 shows the results obtained by measuring the transparency and comprehensively evaluating the film characteristics. Stretchability: As shown in FIG. 5 (B), a strip-shaped test piece P is prepared by cutting the sample perpendicularly to the film-forming direction so that the width of the strip is 15 mm and the length is 100 mm or more. Then, the test piece P is chucked at 100 mm intervals and laterally (X
It was stretched in the (Y direction) by 25% at a speed of 300 mm / min, the stretching was released, and the S-S curve was measured to measure a stress of 0 strain d and a permanent strain e after standing for 10 minutes. Heat resistance slip resistance: A plate heater 21 was attached to the dynamic friction measuring device 20 shown in FIG. 9 (JIS K7125-198
7), a rectangular parallelepiped metal sliding piece 22 can be measured so that the lateral direction of the non-corona treated surface of the sample film 1 can be measured.
The plate 21 heated to 40 °, 50 ° and 60 ° C. is pressure-bonded, and after 3 minutes, the metal slide piece 22 is attached to the load cell 25.
Was used to measure the dynamic friction coefficient. However, ─ is a value that cannot be measured. Heat shrinkage ratio: A sample cut into 100 × 100 mm was
After immersing in hot water at 0, 70, and 80 ° C. for 1 minute, the dimensional change in the longitudinal direction is evaluated by%. The positive numbers indicate growth, and the negative numbers indicate contraction. Birefringence: KOBRA-21AD as shown in FIG.
The birefringence was measured using a measuring instrument having an H optical system. However, the display is a numerical value of 1 / 1,000,000. Transparency: Haze was measured based on (JIS K7105-1981). Overall Evaluation (Evaluation Criteria) ◎ Good label mounting suitability, transparency and pass-tryer suitability (heat shrinkage ratio) ○ Poor transparency but good label mounting suitability and pass-tryer suitability No practical problems △ Label Either the suitability for wearing or the suitability for the pass-tryer is slightly inferior, but there is no problem in practical use. × The transparency is slightly inferior, but inferior but practical.

[0041]

[Table 2]

[0042]

The density is 0.905 to 0.940 g / cm.
^Within the range of ^3, the molecular structure is uniform, the range of molecular weight distribution is narrow, and the linear low-density polyethylene polymerized by a single-site catalyst can form a stretch label film with excellent stretchability and heat resistance. . Further, the film has a birefringence of 0.001 to 0.001 by light stretching.
Those set to 0.005 are provided with a heat shrinkage rate, and have an effect of preventing wrinkles from being generated on the label even when the plasticizer container filled with the beverage is subjected to the pasteurizer treatment. Further, even if a single-site linear low-density polyethylene having a density of 0.880 to 0.940 g / cm ³ is used, a polymer having low tackiness is blended to form a film having a birefringence index set within the above range. By doing so, the same effect can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a phase difference of birefringence.

FIG. 2 KOBURA-21ADH for measuring birefringence
2 is a schematic view of the optical system of FIG.

FIG. 3 is a conceptual diagram showing an outline of a step of producing an unstretched film used in the present invention.

FIG. 4 is a conceptual diagram showing an outline of a stretching step of a stretch label film.

FIG. 5 (A) is a diagram showing an SS curve of the stretch label film of the present invention. (B) It is a figure which shows the position of the sample which measures an SS curve.

FIG. 6 is a schematic view for explaining the formation of the stretch label of the present invention. (A) A film for stretch labels. It is a perspective view which shows the concept which provided the pattern layer in the (B) film. (C) It is a perspective view which shows the concept which joined the film in the shape of a cylinder.

FIG. 7 is a conceptual diagram showing an outline of a step of attaching a stretch label to a container. (A) It is a perspective view of the stretch label cut into one sheet. (B) It is a conceptual diagram which shows the state of the label extended | stretched for inserting. (C) It is a conceptual diagram which shows the state which inserted the label in the container. It is a conceptual diagram which shows the state where (D) the label was closely attached to the container.

FIG. 8 is a conceptual diagram illustrating pasteurizer processing of a container filled with a carbonated beverage. (A) A container filled with a carbonated drink. (B) is a diagram in which hot water is showered and pasteurizer processing is performed. (C) A container for a carbonated beverage that has been sterilized and has been filled.

FIG. 9 is a conceptual diagram of a measuring device for explaining a method of evaluating heat resistant slip resistance.

[Explanation of Codes] 1 unstretched film 10 film for stretch label 2 pattern layer 3 adhesive 4 joint 5 stretch label 6 container 61 container with label 62 container filled with contents 63 sterilized and cooled container 7 label stretching Direction 8 Contents 9 Hot water 11 T die 12 Air chamber 13 Cooling roll 14 Nip roll 16 Preheating part 17 Drawing part 18 Cooling part 19 Heater 20 Dynamic friction measuring device 21 Plate heater 22 Sliding piece 25 Load cell D strain d Stress 0 strain e Permanent strain XY Stretching direction when measuring stress M Film forming direction S Stress P Strip H Strip width L Strip length K KOBRA-21DH Optical system R Phase difference t Film thickness 100 Ray 101 Ordinary ray 102 Extraordinary ray 106 Photoreceptor 107 Polarizer 108 Analyzer 109 Parallel Nicol

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Claims (2)

[Claims] 1. A thermoplastic composition containing at least 95% by weight of a linear low-density polyethylene simple substance having a density of 0.905 to 0.940 g / cm ³ polymerized using a single-site catalyst, or a single-site system. A thickness 30 composed of 55 to 98% by weight of linear low-density polyethylene having a density of 0.880 to 0.940 g / cm ³ polymerized using a catalyst and 2 to 45% by weight of a polyolefin resin. ~
A stretch label film, wherein the film of 150 μm has a birefringence of 0.001 to 0.005 measured using a wavelength of 590 nm. 2. A stretch label film, wherein the film according to claim 1 contains a lubricant, an antiblocking agent, an antioxidant and / or an antistatic agent.