JP6430755B2 - Heat-shrinkable cylindrical label - Google Patents

Description

  The present invention relates to a heat-shrinkable cylindrical label attached to an adherend such as a container.

Conventionally, heat-shrinkable cylindrical labels are attached to various containers such as beverage containers. The heat-shrinkable cylindrical label is generally called a shrink label or a shrink tube.
The heat-shrinkable cylindrical label is formed by superposing the back surface of the first side end portion of the heat-shrinkable base material on the surface of the second side end portion, and bonding the overlap surfaces to form a seal portion. It is formed in a shape.
A single-layer film may be used as the heat-shrinkable base material for forming the heat-shrinkable cylindrical label, but for the purpose of imparting various functions, a heterogeneous laminated film in which different resins are laminated may be used. Many. For example, Patent Document 1 discloses a resin composition containing an amorphous aromatic polyester resin as a main component and 0.5 to 20 parts by mass of a plasticizer with respect to 100 parts by mass of an amorphous aromatic polyester resin. And a central layer (B layer) composed of a resin composition mainly composed of a styrene-conjugated diene copolymer and / or a hydrogenated product thereof, A heat-shrinkable cylindrical label having at least a three-layer laminated structure in which B layers / A layers are laminated in this order is disclosed. In such a heat-shrinkable cylindrical label, delamination hardly occurs due to heat-shrink processing.

  However, even with the heat-shrinkable cylindrical label, delamination may occur or the layers may be easily separated depending on the heat-shrink processing conditions. In particular, when the end surface of the first side end portion of the seal portion comes into contact with a foreign substance after heat shrink processing, the layers of the resin layers are easily peeled off. Since the first side end of the seal portion is located on the surface side of the heat-shrinkable cylindrical label, if delamination occurs on the end face, the appearance of the label deteriorates and the heat-shrinkable cylindrical label is heated. In the process of transporting the shrink-fitted container, the resin layer further peels off due to contact between adjacent containers or contact with mechanical devices, and in some cases, the resin layer may be partially broken.

JP 2009-178887 A

  An object of the present invention is to provide a heat-shrinkable cylindrical label that hardly causes delamination at a seal portion.

In the heat-shrinkable cylindrical label of the present invention, the back surface of the first side end portion of the heat-shrinkable base material is superposed on the surface of the second side end portion, and the superposed surfaces are bonded together to form a seal portion. The heat-shrinkable base material includes a heat-shrinkable laminated film having seven or more resin layers, and the laminated film has a surface layer, an intermediate layer, and a back layer. The intermediate layer includes an alternately laminated portion in which first resin layers and second resin layers having different resin components are alternately laminated, and a total of the first resin layer and the second resin layer is 5 layers or more, and the surface layer Is a resin layer mainly composed of a polyester-based resin, and in the state of heat shrink processing, at least the end surface of the alternately laminated portion of the end surfaces of the first side end portion is with respect to the back surface of the first side end portion. The inclined surface is inclined at an acute angle.

In the preferred heat-shrinkable cylindrical label of the present invention, the main component resin of the surface layer and the main component resin of the back layer are the same .
In a preferred heat-shrinkable cylindrical label of the present invention, the back layer is a resin layer mainly composed of a polyester resin, and the first resin layer of the intermediate layer is a resin layer mainly composed of a polyester resin. The second resin layer of the intermediate layer is a resin layer mainly composed of polystyrene resin or polyethylene resin .
A preferable heat-shrinkable cylindrical label of the present invention is an inclined surface in which the end surfaces of the surface layer, the back layer, the first resin layer, and the second resin layer are inclined at an acute angle with respect to the back surface of the first side end portion, respectively. And the inclination angle of the end face of the surface layer is the largest, the inclination angle of the end face of the back layer is the smallest, and the inclination of the end faces between the adjacent first resin layer and second resin layer It has a part where the corner changes .
A preferable heat-shrinkable cylindrical label of the present invention is between the end surface of the back layer and the end surface of the resin layer adjacent to the back layer, or between the end surface of the adjacent first resin layer and the end surface of the second resin layer. Are stepped.

  Since the heat-shrinkable cylindrical label of the present invention is an inclined surface in which the end surface of the first side end portion of the seal portion is inclined, each resin layer constituting the laminated film is difficult to delaminate and has excellent durability. ing.

The perspective view of the state which was the heat-shrinkable cylindrical label before heat-shrink processing, and was expanded in the cylinder shape. The front view of the state which folded the heat-shrinkable cylindrical label flatly. Sectional drawing cut | disconnected by the III-III line | wire of FIG. The expanded sectional view of the seal | sticker part of the heat-shrinkable cylindrical label of FIG. The front view which shows the state which heat-shrink-processed the heat-shrinkable cylindrical label, and was attached to the to-be-adhered body. It is sectional drawing cut | disconnected by the VI-VI line of FIG. 5, Comprising: The expanded sectional view of the seal part of the heat-shrinkable cylindrical label after heat-shrink processing. The further expanded sectional view of the seal part concerning one embodiment. The further expanded sectional view of the seal part concerning other embodiments.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The circumferential direction of the heat-shrinkable cylindrical label means the direction around the axis of the cylinder when it is expanded into a cylindrical shape. The front surface means a surface located outside the heat-shrinkable cylindrical label (cylinder), and the back surface means a surface located inside. Furthermore, the description “PPP to QQQ” means “PPP or more and QQQ or less”.
Note that in each cross-sectional view, the thickness, dimensions, and the like are different from the actual ones.

(Heat-shrinkable cylindrical label before heat-shrinking)
1 to 4 show a heat-shrinkable cylindrical label before being attached to an adherend (before heat shrinking), but FIG. 1 is a state in which the label is expanded just before being attached to the adherend. FIG. 2 to FIG. 4 show the heat-shrinkable cylindrical label in a state of being folded flat. Usually, the heat-shrinkable cylindrical label 1 is conceptually in the form of a long cylindrical label elongated body in which a plurality thereof are continuously connected in the longitudinal direction (the cylindrical label elongated body is not shown). The cylindrical label elongate body is stored and transported in a state of being flattened and wound on a roll, and when being attached to an adherend, by cutting the elongate body at a predetermined location, A flat heat-shrinkable cylindrical label 1 as shown in FIGS. 2 and 3 is obtained. As shown in FIG. 1, the flat heat-shrinkable cylindrical label 1 is attached to an adherend by being expanded into a tubular shape, fitted onto the adherend, and heated.

The heat-shrinkable cylindrical label 1 is formed of a tubular body in which a heat-shrinkable base material including a laminated film 2 having heat-shrinkability is formed in a tubular shape.
Specifically, the heat-shrinkable base material is rounded so that the heat-shrink direction is the circumferential direction, and the back surface of the first side end portion 21 of the heat-shrinkable base material is superimposed on the surface of the second side end portion 22. The heat-shrinkable cylindrical label 1 is configured by adhering the overlapping surfaces using a solvent or an adhesive. A portion where the overlapping surfaces (the back surface of the first side end portion 21 and the surface of the second side end portion 22) are bonded together is generally called a seal portion.
In the seal portion 3 configured by adhering the back surface 21b of the first side end portion 21 to the surface of the second side end portion 22, the first side end portion 21 is located outside the heat-shrinkable cylindrical label 1. And the 2nd side edge part 22 is located inside the heat-shrinkable cylindrical label 1. FIG. Therefore, the end surface 21a of the first side end portion 21 is exposed to the outside. In the heat-shrinkable cylindrical label before heat-shrinking, the end surface 21a of the first side end portion 21 is a vertical surface that is substantially orthogonal to the back surface 21b of the first side end portion 21.
In addition, in this specification, an end surface means the surface extended in the thickness direction. The end surface 21a of the first side end portion 21 refers to a surface extending in the thickness direction at the edge of the first side end portion 21 of the heat-shrinkable base material.
In the seal portion 3, as shown in FIG. 4, the distal end portion of the second side end portion 22 located on the inner side extends from the seal portion 3 in the circumferential direction and is bonded to the first side end portion 21. The remainder 23 is not set. In other words, by bonding a part of the second side end 22 to the first side end 21 and non-bonding the other part to the first side end 21, the second side end 22 is A surplus margin 23 (free end) that is not bonded to the first side end 21 is provided between the edge and the edge of the seal portion 3. The extension length of the remainder allowance 23 is, for example, about 3 mm to 7 mm. On the other hand, the back surface of the first side end portion 21 located outside is bonded to the surface of the second side end portion 22 up to the edge. In other words, the seal portion 3 reaches the edge of the first side end portion 21.

The heat-shrinkable substrate includes a heat-shrinkable laminated film 2. Preferably, the heat-shrinkable substrate may be one in which a known functional layer selected from a design printing layer, a surface-protecting overcoat layer, a sliding layer and the like is provided on the laminated film 2 (these layers). Functional layer not shown).
The heat-shrinkable substrate (and laminated film 2) has a property of being thermally contracted in at least one direction (main heat-shrink direction) when heated to a required temperature (for example, 70 to 100 ° C.). This property is referred to as heat shrinkability in this specification. The heat-shrinkable base material may be slightly heat-shrinkable or heat-stretched in the other direction (the other direction is a direction perpendicular to the one direction in the film plane). The heat shrinkage rate of the heat-shrinkable substrate is not particularly limited as long as it can be attached to the container. For example, the heat shrinkage rate in one direction when heated to 90 ° C. is 30% or more, preferably It is 40% or more, more preferably 50% or more. In addition, when the heat-shrinkable base material 4 is slightly heat-shrinked or thermally stretched in the other direction, the heat shrinkage rate in the other direction when heated to 90 ° C. is, for example, −5% to 15%, preferably Is -3% to 10%. The minus of the thermal contraction rate means thermal extension. The heat shrinkage rate when heated to 90 ° C. is the length of the base material before heating (original length) and the length of the base material after dipping the base material in warm water at 90 ° C. for 10 seconds ( It is a ratio of the length after immersion) and is obtained by substituting into the following formula.
Formula: heat shrinkage rate (%) = [{(original length in one direction (or other direction)) − (length after immersion in one direction (or other direction))} / (one direction (or other direction) ) Original length)] × 100.
The laminated film 2 has 7 or more resin layers, preferably 9 or more layers, more preferably 11 or more layers. The upper limit of the number of laminated resin layers of the laminated film 2 is not particularly limited, but is, for example, 100 layers or less, preferably 67 layers or less, more preferably 35 layers or less. Of the seven or more resin layers, for the five or more layers, the first resin layer A and the second resin layer B are alternately laminated. The first resin layer A and the second resin layer B are different from each other in resin components, and are preferably different in resin as a main component.
The resin as the main component (hereinafter may be referred to as a main component resin) refers to a resin (mass basis) having the largest amount among the resins contained in each layer.

Specifically, the laminated film 2 has a surface layer 4, an intermediate layer 5, and a back layer 6. The surface layer 4 is a single resin layer located outside when the heat-shrinkable base material is formed into a cylindrical shape (in other words, the heat-shrinkable base material is cylindrical so that the surface of the surface layer 4 is on the outside). The back layer 6 is a single resin layer located inside when the heat-shrinkable base material is formed into a cylindrical shape. The intermediate layer 5 is a plurality of resin layers laminated between the surface layer 4 and the back layer 6.
The laminated film 2 composed of seven or more resin layers is composed of a laminate of resin layers in which the intermediate layer 5 is five or more layers. The intermediate layer 5 is preferably a laminate of 5 to 65 resin layers, more preferably a laminate of 7 to 33 resin layers, and more preferably 9 to 33 layers. It is a laminate of resin layers.
The intermediate layer 5 includes alternating stacked portions 7.
The alternately laminated portion 7 is a portion in which a first resin layer A containing a resin component and a second resin layer B containing a resin component different from the resin are alternately laminated adjacent to each other in the thickness direction, The sum total of the 1st resin layer A and the 2nd resin layer B is a part of five or more layers. The resin component of the first resin layer A and the resin component of the second resin layer B are different from each other. (1) A resin having a certain system is included as a main component resin. If they are different, (2) both include a resin of a certain system as a main component resin, but if the specific resin structure is different, (3) includes both a resin of a certain system as a main component resin and When resin other than the system is included and the resin other than the system is different, (4) When both main component resins are different, (5) Two or more selected from (1) to (3) If the above conditions are satisfied, etc. may be mentioned.
Preferably, the alternately laminated portion 7 is a portion in which first resin layers A and second resin layers B having different main component resins are alternately laminated adjacent to each other in the thickness direction, and the first resin layer The sum of A and the second resin layer B is a portion of five layers or more. Since the alternately laminated portion 7 includes the first and second resin layers A and B having different main component resins, a step is easily generated between the end surface of the adjacent first resin layer A and the end surface of the second resin layer B. .
As for the alternately laminated part 7, Preferably, the sum total of the 1st resin layer A and the 2nd resin layer B is 7 layers or more, More preferably, it is 9 layers or more. In the alternately laminated portion 7, the upper limit of the total number of laminated layers of the first resin layer A and the second resin layer B is the number of laminated layers of the laminated film 2, and preferably corresponds to the upper limit of the number of laminated intermediate layers.
In FIG. 4, the intermediate layer 5 is made of a laminate of five resin layers, and the alternate laminate portion 7 is made of the five resin layers (that is, the entire intermediate layer 5 is composed of the alternate laminate portions 7. ).
In the case where the total of the first resin layer A and the second resin layer B is an odd number layer of 5 or more, the configuration of the alternately laminated portion 7 is first resin layer / second resin layer / first in order from the surface layer side. Resin layer / second resin layer / first resin layer /..., Or second resin layer / first resin layer / second resin layer / first resin layer / second resin layer /. In addition, the configuration of the alternately laminated portion 7 in the case where the total of the first resin layer and the second resin layer is an even number layer of 6 layers or more is the first resin layer / second resin layer / first in order from the surface layer side. Resin layer / second resin layer / first resin layer / second resin layer /..., Second resin layer / first resin layer / second resin layer / first resin layer / second resin layer / first Resin layer / ... may be used. Therefore, the layer structure of the laminated film 2 in these cases is as follows: surface layer / first resin layer / second resin layer / first resin layer /.../ second resin layer / first resin layer / back layer; surface layer / second layer Resin layer / first resin layer / second resin layer /.../ first resin layer / second resin layer / back layer; surface layer / first resin layer / second resin layer / first resin layer /.../ second resin Layer / first resin layer / second resin layer / back layer; surface layer / second resin layer / first resin layer / second resin layer /.. ./First resin layer / second resin layer / first resin layer / back One of the layers.

The main component resin for the surface layer and the main component resin for the back layer are not particularly limited. , Polyamide resins, thermoplastic elastomers and the like. Especially, it is preferable that a surface layer and / or a back layer are layers which have polyester-type resin as a main component resin from a viewpoint of damage prevention. Furthermore, since it is difficult for delamination to occur in the seal portion, at least the surface layer is more preferably a layer containing a polyester resin as a main component resin, and more preferably a layer containing 80% by mass or more of the polyester resin. A layer containing 90% by mass or more of a polyester resin is particularly preferable. Since a layer mainly composed of a polyester resin has a relatively large shrinkage stress, the surface layer is a layer mainly composed of a polyester resin. Since it contracts greatly, the end surface of the first side end portion with a small inclination angle can be formed. As the inclination angle of the end face of the first side end portion is decreased, a heat-shrinkable cylindrical label having a higher delamination preventing effect can be configured.
Further, the main layer resin may be different between the front layer and the back layer, but it is preferable that the main layer resin is the same between the front layer and the back layer because the overlapping surface in the seal portion 3 can be firmly adhered. .
The main component resin of the first resin layer and the main component resin of the second resin layer are not particularly limited as long as they are different. For example, the resin is listed according to the type of resin, and polyester resin, polystyrene resin are listed. Polyolefin resin, vinyl chloride resin, polycarbonate resin, polyamide resin, thermoplastic elastomer, and the like. Among them, the main component resin of the first resin layer is one kind of resin selected from the group of polyester resins, polystyrene resins and polyolefin resins, and the main component resin of the second resin layer is the first resin layer. It is preferable that it is 1 type chosen from the said group except main component resin. Polyester resins, polystyrene resins, and polyolefin resins have good heat shrinkability when a film is formed and have a required rigidity. Therefore, they are used as the main resin of the first resin layer and the second resin layer. It is preferable to use it. In particular, when the surface layer is mainly composed of a polyester-based resin, one of the first and second resin layers is mainly composed of a polyester-based resin and the other is mainly composed of a polystyrene-based resin. It is preferable that one has a polyester resin as a main component and the other has a polyolefin resin as a main component, and the one has a polyester resin as a main component and the other has a polystyrene resin as a main component. It is preferable (the same applies when the back layer is mainly composed of a polyester resin).
In addition, when a surface layer has a polyester-type resin as a main component, it is preferable that the 1st resin layer or 2nd resin layer adjacent to it has a polyester-type resin as a main component (a back layer has a polyester-type resin as a main component. The same applies to
Moreover, the surface layer, the back layer, the first resin layer, and the second resin layer may each contain a resin other than the main component resin. When these include a resin other than the main component resin, the interlayer strength between the first resin layer and the second resin layer is improved, so that the resin other than the main component resin in the first resin layer is the main component of the second resin layer. Resin is preferable, and the resin other than the main component resin in the second resin layer is preferably the main component resin of the first resin layer. Further, since the interlayer strength with the surface layer is improved, the resin other than the main component resin in the resin layer in contact with the surface layer of the first resin layer and the second resin layer is preferably the main component resin of the surface layer. Since the interlayer strength with the layer is improved, the resin other than the main component resin in the resin layer in contact with the back layer of the first resin layer and the second resin layer is preferably the main component resin of the back layer.
Although content of resin other than main component resin is not specifically limited, 5 mass%-45 mass% are preferable with respect to the whole layer, 10 mass%-40 mass% are more preferable, and 15 mass%-35 mass% are 15 mass%-35 mass%. Further preferred.

  As described above, the main component resin is a resin (mass basis) having the largest amount of resins contained in each layer, but there are two or more kinds of resins having the largest number of resins contained in the layer. When present, the layer also corresponds to a layer containing as a main component resin each of the two or more types of resins. For example, a resin layer containing 50% by mass of a polyester resin and 50% by mass of a polystyrene resin is a layer mainly composed of a polyester resin and also a layer mainly composed of a polystyrene resin. However, when the resin layer is adjacent to another resin layer containing one type of resin as a main component resin, the resin layer has a resin other than one type of resin as the main component. It corresponds to the layer. For example, when a resin layer containing 50% by mass of a polyester resin and 50% by mass of a polystyrene resin and a resin layer containing a polyester resin as a main component are adjacent to each other, the former resin layer is mainly composed of a polystyrene resin. It is a layer used as a component. When a resin layer containing 50% by mass of a polyester resin and 50% by mass of a polystyrene resin and a resin layer containing a polystyrene resin as a main component are adjacent to each other, the former resin layer is mainly made of a polyester resin. It is a layer used as a component.

  In a preferred embodiment, the laminated film 2 is an odd number layer in which the total of the first resin layer A and the second resin layer B is 5 or more, and the layer configuration is surface layer / first resin layer / second resin layer / first. Resin layer /.../ second resin layer / first resin layer / back layer, wherein the front layer and the back layer are resin layers mainly composed of a polyester resin, and the first resin layer is composed mainly of a polyester resin. The second resin layer is a resin layer mainly composed of polystyrene resin or polyethylene resin (particularly, the second resin layer is a resin layer mainly composed of polystyrene resin).

Examples of the polyester-based resin include polyesters having a dicarboxylic acid component and a diol component as essential components (that is, a structural unit (structural unit) derived from dicarboxylic acid and a diol). Polyester containing at least a structural unit), polylactic acid-based polymer, and the like. Examples of the main polyesters containing at least a structural unit derived from a dicarboxylic acid and a structural unit derived from a diol include a polymer, a copolymer, or a mixture thereof by a condensation reaction of a dicarboxylic acid and a diol.
Examples of the dicarboxylic acid (dicarboxylic acid component) include terephthalic acid, isophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 5-t-butylisophthalic acid, 4,4′-biphenyldicarboxylic acid, and trans-3. , 3′-stilbene dicarboxylic acid, trans-4,4′-stilbene dicarboxylic acid, 4,4′-dibenzyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,3-naphthalene Dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,2,6,6-tetramethylbiphenyl-4,4′-dicarboxylic acid, 1,1,3-trimethyl-3-phenyl Indene-4,5-dicarboxylic acid, 1,2-diphenoxyethane-4,4′-dicarboxylic acid, diphenyl ether dical Aromatic dicarboxylic acids such as acid, 2,5-anthracene dicarboxylic acid, 2,5-pyridinedicarboxylic acid, and substituted products thereof; oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberin Acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, icosanedioic acid, docosanedioic acid, 1, Aliphatic dicarboxylic acids such as 12-dodecanedioic acid and substituted products thereof; 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid 1,4-decahydronaphthalenedicarboxylic acid, 1,5-decahydronaphthalene Carboxylic acid, 2,6-decahydronaphthalene dicarboxylic acid, and include alicyclic dicarboxylic acids such as substituted versions thereof. The dicarboxylic acid may be used alone or in combination of two or more.

  Examples of the diol (diol component) include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 2,2-diethyl-1,3 -Propanediol, 1,8-octanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2,4-dimethyl-1,3-hexanediol, 1,10-decanediol, Aliphatic diols such as polyethylene glycol and polypropylene glycol; 1,2-cyclohexanedimethanol, , 3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol and other alicyclic diols; 2,2-bis (4-β-hydroxy And ethylene oxide adducts of bisphenol compounds such as ethoxyphenyl) propane and bis (4-β-hydroxyethoxyphenyl) sulfone, and aromatic diols such as xylylene glycol. The diol may be used alone or in combination of two or more.

In addition to the above, the polyester resin includes oxycarboxylic acids such as p-oxybenzoic acid and p-oxyethoxybenzoic acid; monocarboxylic acids such as benzoic acid and benzoylbenzoic acid; polyvalent carboxylic acids such as trimellitic acid. A structural unit derived from a monohydric alcohol such as polyalkylene glycol monomethyl ether; a polyhydric alcohol such as glycerin, pentaerythritol, or trimethylolpropane;
Above all, the polyester resin is preferably an aromatic polyester resin from the viewpoints of thermal shrinkage, mechanical strength, and heat resistance. The aromatic polyester-based resin means that 50 mol% or more (preferably 70 mol% or more) of the total dicarboxylic acid component is 50 mol% or more (preferably 70 mol% or more of the total diol component). Is a polyester resin whose aromatic diol is 70 mol% or more. Furthermore, the aromatic polyester-type resin which is a polymer by the condensation reaction of the dicarboxylic acid containing aromatic dicarboxylic acid and the diol containing aliphatic diol, or a mixture thereof is preferable.
The aromatic polyester-based resin has a high heat shrinkage rate and can hardly cause delamination of each resin layer. Therefore, the aromatic polyester-based resin does not include a single repeating unit but includes a modifying component (copolymerization component). A modified aromatic polyester resin is preferred. As the modified aromatic polyester resin, for example, at least one of a dicarboxylic acid component and a diol component is composed of two or more components, that is, a modified aromatic polyester resin containing a modified component in addition to the main component. Resins are preferred. In other words, the aromatic polyester-based resin is preferably a modified aromatic polyester-based resin including a structural unit derived from at least two kinds of dicarboxylic acids and / or a structural unit derived from at least two kinds of diols.

Among the modified aromatic polyester resins, among the above, in polyethylene terephthalate (PET) using terephthalic acid as the dicarboxylic acid component and ethylene glycol (EG) as the diol component, a part of the dicarboxylic acid component and / or diol component A modified PET in which is replaced with a modified component (that is, another dicarboxylic acid component and / or another diol component) is preferably exemplified.
Examples of the dicarboxylic acid component used as the modifying component (copolymerization component) of the modified aromatic polyester resin (particularly, modified PET) include cyclohexanedicarboxylic acid, adipic acid, isophthalic acid, and the like. Isophthalic acid is preferred. Examples of the diol component used as the modifying component include 2,2-dialkyl-1,3-propanediol such as 1,4-cyclohexanedimethanol (CHDM) and neopentyl glycol (NPG), and diethylene glycol. Of these, CHDM is preferred. The alkyl group in the 2,2-dialkyl-1,3-propanediol is preferably an alkyl group having 1 to 6 carbon atoms, and the two alkyl groups may be the same alkyl group, It may be a different alkyl group.
The aromatic polyester-based resin is not particularly limited. Specifically, from the viewpoint of heat shrinkability (shrinkage characteristics), terephthalic acid is used as the dicarboxylic acid component, and ethylene glycol (EG) is used as the diol component. Polyethylene terephthalate (PET): A modified aromatic polyester resin ("CHDM") using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the diol component, and 1,4-cyclohexanedimethanol (CHDM) as the copolymerization component. Copolymerized PET ”); modified aromatics using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the main component as the diol component, and 2,2-dialkyl-1,3-propanediol as the copolymer component Polyester resin (“2,2-Dial May be referred le-1,3-propanediol copolymer PET ") are preferred. Among the 2,2-dialkyl-1,3-propanediol copolymerized PET, in particular, terephthalic acid is used as the dicarboxylic acid component, ethylene glycol is the main component, and neopentyl glycol (NPG) is the copolymerized component as the diol component. The modified aromatic polyester-based resin used as (sometimes referred to as “NPG copolymerized PET”) is preferred. The aromatic polyester resin is particularly preferably CHDM copolymerized PET and / or 2,2-dialkyl-1,3-propanediol copolymerized PET, and more preferably CHDM copolymerized PET and / or NPG copolymerized. PET, most preferably CHDM copolymerized PET. In addition, copolymer components other than CHDM and 2,2-dialkyl-1,3-propanediol are used for the CHDM copolymerized PET and 2,2-dialkyl-1,3-propanediol copolymerized PET, respectively. For example, isophthalic acid or diethylene glycol may be further copolymerized.

In the modified aromatic polyester resin, the copolymerization ratio of the copolymerization component (modification component) [ratio of the copolymerization dicarboxylic acid component to the total dicarboxylic acid component (ratio), or the ratio of the copolymerization diol component to the total diol component ( The ratio)] is not particularly limited, but is preferably 10 mol% or more (for example, 10 to 40 mol%), more preferably 15 mol% or more from the viewpoint of optimizing the thermal deformation behavior of the layer and reducing delamination. (For example, 15 to 40 mol%). Among them, for example, in the case of CHDM copolymerized PET, the ratio of CHDM is preferably 10 to 30 mol% (EG is 70 to 90 mol%), more preferably 12 to 25 mol% (EG is 75%) in all diol components. ~ 88 mol%). In the case of 2,2-dialkyl-1,3-propanediol copolymerized PET, the ratio of 2,2-dialkyl-1,3-propanediol (the ratio of NPG in the case of NPG copolymerized PET) is 10-30 mol% (EG is 70-90 mol%) in a diol component is preferable. Further, a part of the EG component (preferably 1 to 30 mol% in the total diol component) may be replaced with diethylene glycol.
The aromatic polyester resin is not particularly limited, but is preferably a substantially amorphous aromatic polyester resin, and more preferably an aromatic polyester resin that is an amorphous saturated polyester resin. Since the aromatic polyester resin becomes difficult to crystallize by modifying as described above, it can be made substantially amorphous by modification, for example. By making the aromatic polyester-based resin amorphous, extrusion at a relatively low temperature becomes possible. Thereby, the shrinkage stress of the heat-shrinkable cylindrical label can be reduced while the heat shrinkage rate is high and the shrinkage is high.
The degree of crystallinity of the polyester-based resin measured by the differential scanning calorimetry (DSC) method (measured at a heating rate of 10 ° C./min) is not particularly limited, but is preferably 15% or less, more preferably 10% It is as follows. Further, the polyester-based resin is most preferably a resin in which a melting point (melting peak) is hardly observed when measured by the DSC method (that is, a crystallinity of 0%). The crystallinity can be calculated from a value of heat of crystal fusion obtained by DSC measurement, with a sample having a clear crystallinity measured by the X-ray method or the like as a standard. The heat of crystal melting is, for example, using a DSC (Differential Scanning Calorimetry) device manufactured by Seiko Instruments Inc. and performing a nitrogen seal at a sample amount of 10 mg and a heating rate of 10 ° C./min. It can be determined from the area of the melting peak when the temperature is raised to room temperature and then raised again. The crystallinity is preferably measured from a single resin, but when measured in a mixed state, the melting peak of the target aromatic polyester resin is subtracted from the melting peak of the resin to be mixed. You can ask for.
The weight average molecular weight (Mw) of the polyester resin is not particularly limited, but is preferably 15,000 to 100,000, more preferably 30,000 to 90,000, and still more preferably, from the viewpoint of melting behavior and shrinkage behavior. Is 30,000-80,000. In the case of 2,2-dialkyl-1,3-propanediol copolymerized PET, 50,000 to 70,000 is particularly preferable.
Although the glass transition temperature (Tg) of the said polyester-type resin is not specifically limited, 60-80 degreeC is preferable from a viewpoint of an extending | stretching characteristic and heat shrinkability, More preferably, it is 60-75 degreeC. The Tg can be controlled by the type of dicarboxylic acid or diol constituting the polyester resin and the copolymerization ratio of the copolymerization component (modification component) used for modification. In the present specification, the glass transition temperature (Tg) of the resin can be measured by DSC (differential scanning calorimetry) in accordance with, for example, JIS K7121. The DSC measurement is not particularly limited. For example, the DSC measurement can be performed using a differential scanning calorimeter “DSC6200” manufactured by Seiko Instruments Inc. under a temperature rising rate of 10 ° C./min.
Commercially available products may be used as the aromatic polyester-based resin, for example, “EMBRACE 21214”, “EMBRACE LV” (CHDM copolymerized PET) manufactured by Eastman Chemical (Eastman Chemical), Bell Co., Ltd. "Belpet MGG200" (2,2-dialkyl-1,3-propanediol copolymerized PET) manufactured by Polyester Products, "Belpet E02" (NPG copolymerized PET) manufactured by Bell Polyester Products, etc. are available on the market. .

  The polylactic acid polymer means a polymer containing lactic acid (D-lactic acid, L-lactic acid, DL-lactic acid, or a mixture thereof) as a monomer component, and lactic acid and other hydroxycarboxylic acid or lactone Or a copolymer of lactic acid with other dicarboxylic acids and / or diols. Other hydroxycarboxylic acids include, for example, glycolic acid, 2-methyllactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxy-3,3-dimethyl Examples include butyric acid and 2-hydroxycaproic acid. Examples of lactones include γ-butyrolactone, δ-valerolactone, and ε-caprolactone. Moreover, as dicarboxylic acid, the dicarboxylic acid illustrated and demonstrated as a component which comprises the above-mentioned polyester-type resin, etc. are mentioned. Examples of the diol include diols exemplified and described as components constituting the above-described polyester resin. These hydroxycarboxylic acids, lactones, dicarboxylic acids, or diols may be mixed with lactic acid in a monomer state and introduced into a polymer as a random copolymer, or an oligomer or prepolymer previously polymerized as a polyester. May be introduced into the polymer in the form of a block copolymer with lactic acid.

The composition ratio of optical isomers of lactic acid constituting the polylactic acid-based polymer (content ratio of D-form and L-form) varies depending on the required physical properties and is not particularly limited, but from the viewpoint of crystallinity control The ratio of D-lactic acid to the total lactic acid component is 1 to 20% by mass (preferably 1 to 15% by mass), or the ratio of L-lactic acid to the total lactic acid component is 1 to 20% by mass (preferably 1 to 1% by mass). 15% by mass). Especially, the case where the ratio of D-lactic acid with respect to all the lactic acid components is 1-20 mass% is more preferable.
The ratio of lactic acid in the total monomers constituting the polylactic acid polymer is not particularly limited, but is preferably 50 mol% or more, more preferably 65 mol% or more, and further preferably 80 mol% or more. The upper limit of the lactic acid ratio is not particularly limited, but may be 100 mol%. The polylactic acid polymer may be used alone or in combination of two or more. For example, two or more polylactic acid polymers having different ratios of L-lactic acid and D-lactic acid can be used in combination.
The polylactic acid polymer can be produced, for example, by polymerizing lactic acid produced from starch obtained from corn or potato. The polymerization method is not particularly limited, and a known or conventional method such as a condensation polymerization method or a ring-opening polymerization method can be employed. For example, in the polycondensation method, lactic acid or a polylactic acid polymer having an arbitrary composition can be obtained by directly dehydrating condensation of lactic acid and other monomer components. In the ring-opening polymerization method, lactide, which is a cyclic dimer of lactic acid, is polymerized in the presence of a suitable catalyst to obtain a polylactic acid polymer having an arbitrary composition.
The weight average molecular weight (Mw) of the polylactic acid polymer is not particularly limited, but is usually about 5,000 to 100,000, preferably about 10,000 to 50,000, from the viewpoint of mechanical properties and melt viscosity. . If the weight average molecular weight is too small, the mechanical properties and heat resistance may be inferior. If the weight average molecular weight is too large, moldability may be reduced.

The polystyrene resin is a polymer composed of a styrene monomer as an essential monomer component. That is, it is a polymer containing at least a structural unit derived from a styrene monomer in the molecule (in one molecule). The polystyrene resin may be a homopolymer or a copolymer.
Although it does not specifically limit as said styrene-type monomer, For example, styrene, alpha-methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, p-isobutyl styrene, pt-butyl styrene, Examples include chloromethylstyrene. Among these, styrene is preferable from the viewpoint of availability, material price, and the like. In addition, the said styrene-type monomer may use only 1 type, and may use 2 or more types.
Although it does not specifically limit as what is contained in the type | system | group of the said polystyrene-type resin, For example, the homopolymer of styrene-type monomers, such as general purpose polystyrene (GPPS) which is a homopolymer of styrene; Two or more types of styrene-type Copolymer composed only of monomers as monomer component; styrene-diene copolymer; copolymer such as styrene-polymerizable unsaturated carboxylic acid ester copolymer; polystyrene and synthetic rubber (for example, , Polybutadiene, polyisoprene, etc.), impact-resistant polystyrene (HIPS) such as polystyrene obtained by graft-polymerizing styrene to synthetic rubber; polymers containing styrene monomers (for example, styrene monomers and (meta A rubbery elastic body is dispersed in a continuous phase of a copolymer of an acrylate ester monomer) and the copolymer is dispersed in the rubbery elastic body. Shifted polymerization was polystyrene (referred graft type high impact polystyrene "graft HIPS"), such as styrene elastomer. As the polystyrene resin, a styrene-diene copolymer is preferable. In addition, the said polystyrene-type resin may use only 1 type, and may use 2 or more types.
The styrene-diene copolymer is a copolymer composed of a styrene monomer and a diene (particularly, conjugated diene) as essential monomer components. That is, it is a polymer containing at least a structural unit derived from a styrene monomer and a structural unit derived from a diene (particularly conjugated diene) in the molecule (in one molecule).
The diene is not particularly limited, but is preferably a conjugated diene, such as 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 1, Examples include 3-pentadiene, 1,3-hexadiene, chloroprene. Among these, 1,3-butadiene is particularly preferable. That is, the styrene-diene copolymer is preferably a styrene-butadiene copolymer. In addition, the said diene may use only 1 type and may use 2 or more types.

The monomer component constituting the styrene-diene copolymer may further include a monomer component other than the styrene monomer and the diene. Examples of the monomer component other than the styrene monomer and the diene include a vinyl monomer, a polymerizable unsaturated carboxylic acid ester, and a polymerizable unsaturated carboxylic anhydride.
The form of copolymerization of the styrene-diene copolymer is not particularly limited, and examples thereof include a random copolymer, a block copolymer, and a graft copolymer. Among these, block copolymers are preferable, and examples thereof include styrene block (S) -diene block (D) type, SDS type, DSD type, and SSD type. .
Examples of the styrene-diene copolymer include styrene-isoprene block copolymers such as styrene-butadiene block copolymer (SBC) and styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene. Examples thereof include styrene-butadiene-isoprene block copolymers such as isoprene-styrene block copolymer (SBIS), among which styrene-butadiene block copolymers are preferable. In addition, these copolymers may use only 1 type and may use 2 or more types.
The styrene-butadiene block copolymer is not particularly limited as long as it is a copolymer having alternately a styrene block obtained by polymerizing only a styrene monomer and a butadiene block obtained by polymerizing only butadiene. A styrene-butadiene block copolymer having styrene blocks at both ends, such as a butadiene-styrene block copolymer (SBS) and a styrene-butadiene-styrene-butadiene-styrene block copolymer (SBSBS); Styrene block such as polymer (SB), styrene-butadiene-styrene-butadiene copolymer (SBSB) and styrene-butadiene block copolymer having a butadiene block at the end; butadiene-styrene-butadiene copolymer (BSB), Diene - styrene - butadiene - styrene - butadiene block copolymer, and the like - styrene with butadiene copolymer (BSBSB) butadiene block such at both ends. Among these, a styrene-butadiene block copolymer having a styrene block at both ends is preferable, and SBS is more preferable. In addition, these styrene-butadiene block copolymers may use only 1 type, and may use 2 or more types.
The block copolymer of the styrene-diene copolymer (styrene-diene block copolymer) can be produced by a known and commonly used method for producing a block copolymer. Examples of the method for producing the styrene-diene block copolymer include living polymerization (living radical polymerization, living anion polymerization, living cation) that can easily control the molecular weight, molecular weight distribution, terminal structure and the like of the styrene-diene block copolymer. Polymerization). The living polymerization can be carried out by a known and commonly used method.
The styrene-diene copolymer is not particularly limited, but the content of structural units derived from the styrene monomer is the total mass (100 mass of all styrene-diene copolymers contained in the resin layer). %) Is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, and still more preferably 70 to 90% by mass. On the other hand, the content of the structural unit derived from diene is not particularly limited, but is preferably 5 to 50% by mass with respect to the total mass (100% by mass) of all the styrene-diene copolymers in the resin layer. More preferably, it is 10-40 mass%, More preferably, it is 10-30 mass%. When the content of the structural unit derived from the styrene monomer is 50% by mass or less (that is, when the content of the structural unit derived from diene is 50% by mass or more), the heat-shrinkable cylindrical label Stiffness may be reduced and waist may be weakened.

The content of the structural unit derived from the styrene monomer and the content of the structural unit derived from the diene are the compositions of the styrene-diene copolymer (each styrene-diene copolymer contained in each styrene-diene copolymer). The content of the structural unit and the content of each styrene-diene copolymer in all the styrene-diene copolymers contained in the resin layer can be controlled. More specifically, for example, in the styrene-diene copolymer, the content of the structural unit derived from the styrene monomer is s1 (mass%) and the content of the structural unit derived from the diene is d1 ( Styrene-diene copolymer (PS1) which is (mass%) and the content of structural units derived from styrene monomer is s2 (mass%) and the content of structural units derived from diene is d2 (mass) %) Is a resin mixture composed only of a styrene-diene copolymer (PS2), and the content of PS1 in 100% by mass of the resin mixture (resin mixture of PS1 and PS2) is W1 (% by mass). In the case where the content of PS2 is W2 (mass%), the content of structural units derived from styrene monomers and the content of structural units derived from dienes in the resin mixture are generally Control as follows Kill.
Content (% by mass) of structural unit derived from styrene monomer = (s1 × W1 + s2 × W2) / 100
Content (% by mass) of structural unit derived from diene = (d1 × W1 + d2 × W2) / 100

  Analysis and measurement of the content of the structural unit (a structural unit derived from a styrene monomer and a structural unit derived from a diene) and the content of the structural unit are not particularly limited. For example, nuclear magnetic resonance (NMR), gas chromatograph It can be performed by a tomograph mass spectrometer (GCMS) or the like. In addition, it can measure similarly about the specific styrene-conjugated diene copolymer mentioned later.

In addition, the polystyrene resin may be hydrogenated. That is, the polystyrene resin may be a hydrogenated polystyrene resin (hydrogenated polystyrene resin). The hydrogenated polystyrene resin is not particularly limited, but a hydrogenated styrene-butadiene-styrene block copolymer (SEBS) or a hydrogenated styrene-isoprene-styrene block copolymer which is a resin obtained by adding hydrogen to SBS or SIS. Hydrogenated styrene-diene copolymers such as coalesced (SEPS) are preferred. As the hydrogenated polystyrene resin, only one kind may be used, or two or more kinds may be used.
The polystyrene resin may have a polar group introduced. That is, the polystyrene resin may be a polystyrene resin (modified polystyrene resin) into which a polar group is introduced. The modified polystyrene resin includes a hydrogenated polystyrene resin into which a polar group has been introduced.
The modified polystyrene resin is a polystyrene resin in which a polar group is introduced using a polystyrene resin as a main chain skeleton. The polar group is not particularly limited, and examples thereof include an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, a carboxylic acid chloride group, a carboxylic acid amide group, a carboxylic acid group, a sulfonic acid group, and a sulfonic acid ester group. Sulfonic acid chloride group, sulfonic acid amide group, sulfonic acid group, isocyanate group, epoxy group, amino group, imide group, oxazoline group, hydroxyl group and the like. Among these, an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, and an epoxy group are preferable, and a maleic anhydride group and an epoxy group are more preferable. The modified polystyrene resin has a polar group that has high affinity or can react with the polyester resin, and is compatible with the polystyrene resin, so that the polyester resin layer or polystyrene is the main component. Adhesiveness at room temperature with a layer mainly composed of a resin is increased. Only 1 type may be used for the said polar group, and 2 or more types may be used for it.
The modified polystyrene resin is not particularly limited, but a modified product of hydrogenated styrene-butadiene-styrene block copolymer (SEBS) and a modified product of hydrogenated styrene-propylene-styrene block copolymer (SEPS) are preferable. . That is, the modified polystyrene resin is not particularly limited, but acid anhydride-modified SEBS, acid anhydride-modified SEPS, epoxy-modified SEBS, and epoxy-modified SEPS are preferable, and maleic anhydride-modified SEBS and maleic anhydride are more preferable. Modified SEPS, epoxy-modified SEBS, and epoxy-modified SEPS. Only 1 type may be used for the said modified polystyrene resin, and 2 or more types may be used for it.

The polystyrene resin may be a soft polystyrene resin. The soft polystyrene-based resin is not particularly limited, and examples thereof include styrene-based elastomers, styrene-diene-based copolymers, HIPS (high impact polystyrene) having a large rubber component, and graft HIPS having a large rubber component. Of these, styrene elastomers and styrene-diene copolymers are preferable. As for the said soft polystyrene resin, only 1 type may be used and 2 or more types may be used. The styrene elastomer may include a diene component and may be a styrene-diene copolymer elastomer. In addition, HIPS with much said rubber component means HIPS in which content of a rubber component exceeds 30 mass% with respect to the total mass (100 mass%) of HIPS. The graft HIPS having a large amount of the rubber component refers to graft HIPS in which the content of the rubber component exceeds 30% by mass with respect to the total mass (100% by mass) of the graft HIPS.
The soft polystyrene resin includes a hydrogenated soft polystyrene resin (hydrogenated soft polystyrene resin). The hydrogenated soft polystyrene resin is not particularly limited, but a hydrogenated styrene elastomer and a hydrogenated styrene-diene copolymer (particularly, a styrene-diene copolymer having a large amount of hydrogenated diene components). preferable.
In the styrene-diene copolymer elastomer, the content of structural units derived from diene is preferably 50% by mass or more based on the total mass (100% by mass) of the styrene-diene copolymer. More preferably, it is 60-95 mass%, More preferably, it is 65-90 mass%.
The glass transition temperature (Tg) of the styrene-diene copolymer elastomer is not particularly limited, but is preferably 20 ° C. or less, more preferably 10 ° C. or less, and still more preferably 0 ° C. or less from the viewpoint of interlayer strength.

Among the polystyrene resins, a styrene-diene copolymer is preferable, more preferably a styrene-butadiene copolymer, still more preferably a styrene-butadiene block copolymer, and particularly preferably a styrene block at both ends. Styrene-butadiene block copolymer, most preferably SBS.
Commercially available products may be used as the polystyrene-based resin. For example, “Clearen 530L”, “Clearen 730L” manufactured by Denki Kagaku Kogyo Co., Ltd., “Tufprene 126S”, “Asaprene T411” manufactured by Asahi Kasei Co., Ltd., Kraton Polymer “Clayton D1102A”, “Clayton D1116A” manufactured by Japan Co., Ltd., “Styrolux S”, “Styrolux T” manufactured by Stylorusion Corporation, “Asaflex 840”, “Asaflex 860” manufactured by Asahi Kasei Chemicals Corporation Above, SBS), PS Japan Co., Ltd. “679”, “HF77”, “SGP10”, DIC Corporation “Dick Styrene XC-515”, “Dick Styrene XC-535” (above, GPPS), PS “475D”, “H0103”, “HT47” manufactured by Japan "Dick Styrene GH-8300-5" (above, HIPS) manufactured by DIC Corporation, "Tough Tech H Series" manufactured by Asahi Kasei Chemicals Corporation, "Clayton G Series" manufactured by Shell Japan Corporation (above, SEBS) "Dynalon" (hydrogenated styrene-butadiene random copolymer) manufactured by JSR Corporation, "Septon" (SEPS) manufactured by Kuraray Co., Ltd., "Tuftec M Series" manufactured by Asahi Kasei Chemicals Corporation, manufactured by Daicel Corporation “Epofriend”, “polar group-modified dynalon” manufactured by JSR Corporation, “Reseda” (modified polystyrene resin) manufactured by Toagosei Co., Ltd., and the like.

The polyolefin-based resin is a polymer (including an olefin-based elastomer) composed of olefin as an essential monomer component, that is, a polymer including at least an olefin in a molecule (in one molecule). Although it does not specifically limit as said olefin, For example, alpha-olefins, such as ethylene, propylene, 1-butene, and 4-methyl-1- pentene, are mentioned.
Examples of those included in the polyolefin resin system include, for example, a polymer composed of ethylene as an essential monomer component (polyethylene resin), and a polymer composed of propylene as an essential monomer component ( Polypropylene resins), ionomers, amorphous cyclic olefin polymers, and the like. The polyolefin resin is not particularly limited, but among them, a polyethylene resin, a polypropylene resin, and an amorphous cyclic olefin polymer are preferable, and a polyethylene resin and a polypropylene resin are more preferable. More specifically, the polyolefin resin is preferably an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer, more preferably a propylene-α-olefin copolymer, and a propylene-α-olefin graft copolymer. More preferred are copolymers or propylene-α-olefin random copolymers. The polyolefin resin may be used alone or in combination of two or more.

The polyethylene resin is a polymer composed of ethylene as an essential monomer component, that is, a polymer containing at least a structural unit derived from ethylene in the molecule (in one molecule). Examples of the polyethylene-based resin include ethylene homopolymers; copolymers composed of ethylene and one or more monomer components (monomer components other than ethylene) as essential monomer components (ethylene copolymer). Polymer) and the like.
Examples of monomer components other than ethylene include α-olefins; vinyl monomers such as vinyl chloride; (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, and 5-norbornene- Unsaturated carboxylic acids such as 2,3-dicarboxylic acid; unsaturated carboxylic anhydrides such as maleic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, tetrahydrophthalic anhydride; (meth) acrylic Methyl methacrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid 3- Hydroxypropyl, glycidyl (meth) acrylate, monoethyl maleate, diethyl maleate Which unsaturated carboxylic acid esters; acrylamide, methacrylamide, unsaturated amides or imides, such as maleimide; and vinyl acetate; (meth) sodium acrylate, unsaturated carboxylic acid salts such as zinc (meth) acrylate. Only one type of monomer component other than ethylene may be used, or two or more types may be used.
Examples of the α-olefin include 4 to 4 carbon atoms such as 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene. 20 α-olefins (preferably α-olefins having 4 to 8 carbon atoms) and the like. Only 1 type may be used for the said alpha olefin, and 2 or more types may be used for it.
Examples of the ethylene copolymer include a copolymer composed of ethylene and one or more α-olefins as essential monomer components (ethylene-α-olefin copolymer); an ethylene-vinyl acetate copolymer. Polymer (EVA); ethylene-carboxylic acid copolymer such as ethylene-acrylic acid copolymer (EAA) and ethylene-methacrylic acid copolymer (EMAA); ethylene-ethyl acrylate copolymer (EEA) ), And ethylene-carboxylic acid ester copolymers such as ethylene-methyl methacrylate copolymer (EMMA).
Examples of the polyethylene resin include low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE), and are not particularly limited, but LLDPE is particularly preferable from the viewpoint of heat shrinkability. The LDPE refers to polyethylene having a low density of about 0.850 to 0.945 g / cm ³ that includes at least a structural unit derived from ethylene and is manufactured by a high pressure method. The LLDPE is a low density polyethylene of about 0.850 to 0.945 g / cm ³ having at least a structural unit derived from ethylene, manufactured by a medium / low pressure method, and having a short chain branch.
Content of the structural unit derived from ethylene in the polyethylene resin (100% by mass), that is, content of ethylene in all monomer components (100% by mass) constituting the polyethylene resin is particularly limited. However, it is preferably 80% by mass or more, more preferably 85% by mass or more, still more preferably 90% by mass or more, and the upper limit is 100% by mass, 99% by mass, 98% by mass, or 95% by mass. May be. Moreover, content of the structural unit derived from the α-olefin in the ethylene-α-olefin copolymer (100% by mass), that is, all monomer components constituting the ethylene-α-olefin copolymer ( The content of α-olefin in (100% by mass) is not particularly limited, but is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and further preferably 5 to 10% by mass. Further, in the ethylene-α-olefin copolymer, the total content of the ethylene component and the α-olefin component is not particularly limited, but 90% by mass or more in the ethylene-α-olefin copolymer (100% by mass). It is preferable that it is 95 mass% or more, and 98 mass% or more is further more preferable.
Although the density of the said polyethylene-type resin is not specifically limited, 0.870-0.950g / cm < ³ > is preferable, More preferably, it is 0.890-0.935g / cm < ³ >. Further, the melt flow rate (MFR) (temperature 190 ° C., load 2.16 kg) of the polyethylene resin is not particularly limited, but is preferably 1 to 30 g / 10 minutes from the viewpoint of melt extrusion suitability and productivity, Preferably it is 1-10 g / 10min.
Although the said polyethylene-type resin is not specifically limited, The polyethylene-type resin (metallocene catalyst-type polyethylene resin) obtained by superposing | polymerizing using a metallocene catalyst is preferable. As the metallocene catalyst, a known or conventional metallocene catalyst for olefin polymerization can be used. The polymerization method (copolymerization method) of the polyethylene resin is not particularly limited, and examples thereof include known polymerization methods such as a slurry method, a solution polymerization method, and a gas phase method.
Commercially available products may be used as the polyethylene resin. For example, “Umerit 4540F”, “Umerit 3540F”, “Umerit 2540F”, “Umerit 1540F”, “Umerit 0540F”, “Umerit 5540F”, “ "Umerit 2040FC", "Umerit 0520F", "Umerit 1520F", "Umerit 0520F", "Umerit 715FT", made by Prime Polymer Co., Ltd., "Evolue SP1520", "Evolue SP2040" (and above, metallocene catalyst LLDPE), Japan "Kernel KF260T", "Kernel KF360T", "Kernel KF380", "Kernel KS340T" (metallocene catalyst ethylene / α-olefin copolymer), U Maruzen Polyethylene Co., Ltd. "F234" (LDPE), Ube Maruzen Polyethylene Co., Ltd. "V206", Japan polyethylene Co., Ltd. "Novatec EVA Series" (or more, EVA) is and available in the market.

The polypropylene resin is not particularly limited. For example, a propylene homopolymer (homopolypropylene); a copolymer composed of propylene and one or more olefins (olefins other than propylene) as essential monomer components. Examples thereof include a blend (propylene copolymer). As the propylene copolymer, a copolymer composed of propylene and one or more α-olefins as essential monomer components (propylene-α-olefin copolymer) is particularly preferable. The propylene copolymer is a copolymer containing at least a structural unit derived from propylene and a structural unit derived from olefin in a molecule (in one molecule). The propylene-α-olefin copolymer is a copolymer containing at least a structural unit derived from propylene and a structural unit derived from α-olefin in the molecule (in one molecule). Examples of the α-olefin used as a copolymerization component of the propylene-α-olefin copolymer include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-heptene. , 1-octene, 1-nonene, 1-decene, etc., and an α-olefin having 2 to 20 carbon atoms (excluding propylene). Only 1 type may be used for the said alpha olefin, and 2 or more types may be used for it. The propylene copolymer (propylene-α-olefin copolymer or the like) may be a block copolymer, a random copolymer, or a graft copolymer. Among these, a random copolymer is preferable.
The propylene copolymer is not particularly limited, but the content of the structural unit derived from propylene is preferably 50% by mass or more based on the total mass (100% by mass) of the propylene copolymer. Preferably it is 70 mass% or more, More preferably, it is 75 mass% or more.
Among the above, the propylene copolymer is preferably a propylene-α-olefin copolymer, and particularly preferably a propylene-ethylene copolymer. Although content of the alpha olefin in all the monomer components (100 mass%) which comprises the said propylene- alpha-olefin copolymer is not specifically limited, 1-40 mass% is preferable, More preferably, it is 2- 30 mass%, More preferably, it is 3-25 mass%. In the propylene-α-olefin copolymer, the total content of the propylene component and the α-olefin component is not particularly limited, but is 90% by mass or more in the propylene-α-olefin copolymer (100% by mass). It is preferably 95% by mass or more, more preferably 98% by mass or more. The propylene-α-olefin copolymer may be in any form of a block copolymer, a random copolymer, and a graft copolymer. In the propylene-ethylene copolymer, the ratio of ethylene to propylene is, for example, the former / the latter (mass ratio) = 1/99 to 30/70 (preferably 2/98 to 25/75, more preferably 3/95. It can be selected from the range of about 20/80). The propylene-ethylene copolymer may be in any form of a block copolymer, a random copolymer, and a graft copolymer, and an α-olefin other than ethylene and propylene is further copolymerized. Also good. Further, the propylene copolymer (particularly, propylene-ethylene copolymer) has an isotactic index of 90% or more from the viewpoint of low-temperature shrinkability and heat-shrinkable cylindrical label waist strength. preferable.
The polypropylene resin is not particularly limited, but a polypropylene resin obtained by polymerization using a metallocene catalyst (metallocene catalyst polypropylene resin) is preferable. As the metallocene catalyst, a known or conventional metallocene catalyst for olefin polymerization can be used. It does not specifically limit as a polymerization method (copolymerization method) of the said polypropylene resin, Well-known polymerization methods, such as a slurry method, a solution polymerization method, and a gaseous phase method, are mentioned.
Although the density of the said polypropylene resin is not specifically limited, 0.850-0.950g / cm < ³ > is preferable.
Commercially available products may be used as the polypropylene resin, such as “Wintech WFX6”, “Wintech 1987FC” (metallocene catalyst-based propylene-ethylene random copolymer) manufactured by Nippon Polypro Co., Ltd., Mitsubishi Chemical ( "Zeras # 7000" and "Zeras # 5000" manufactured by Co., Ltd., "Vistamaxx 3020FL" (polypropylene resin) manufactured by ExxonMobil Chemical Co., etc. are available on the market.

Examples of the amorphous cyclic olefin polymer include a copolymer of an α-olefin such as ethylene, propylene, 1-butene, 1-hexene, and 4-methyl-1-pentene and at least one cyclic olefin. (Sometimes referred to as "cyclic olefin copolymer") and cyclic olefin ring-opening polymer or hydrogenated product thereof (sometimes referred to as "cyclic olefin ring-opening polymer or hydrogenated product thereof") Is mentioned. The cyclic olefin copolymer and the cyclic olefin ring-opening polymer or hydrogenated product thereof also include graft-modified products thereof.
Examples of the cyclic olefin used in the amorphous cyclic olefin-based polymer include bicyclo [2.2.1] hept-2-ene (norbornene), tetracyclo [4.4.0.12, 5.17, 10] -3-dodecene, hexacyclo [6.6.1.13, 6.110, 13.02, 7.09,14] -4-heptadecene, octacyclo [8.8.0.12, 9.14, 7.11, 18.113, 16.03, 8.012, 17] -5-docosene, pentacyclo [6.6.1.13, 6.02, 7.09,14] -4-hexadecene, heptacyclo- 5-Icocene, heptacyclo-5-henicocene, tricyclo [4.3.0.12,5] -3-decene, tricyclo [4.4.0.12,5] -3-undecene, pentacyclo [6.5. 1. 3,6.02, 7.09, 13] -4-pentadecene, pentacyclopentadecadiene, pentacyclo [4.7.0.12, 5.08, 13.19,12] -3-pentadecene, nonacyclo [ 9.10.1.14, 7.113, 20.115, 18.02, 10.012, 21.014, 19] -5-pentacocene and the like, and the like. Of these, norbornene is preferable. These cyclic olefins may have substituents such as ester groups such as methoxycarbonyl and ethoxycarbonyl groups, alkyl groups such as methyl groups, haloalkyl groups, cyano groups, and halogen atoms in the ring.
The cyclic olefin copolymer is, for example, the α-olefin and the cyclic olefin in hydrocarbon solvents such as hexane, heptane, octane, cyclohexane, benzene, toluene, xylene, so-called Ziegler catalyst or metallocene catalyst. It can be obtained by polymerization using a catalyst. Such cyclic olefin copolymers are commercially available, and for example, “Apel” manufactured by Mitsui Chemicals, Inc., “TOPAS” manufactured by Polyplastics Co., Ltd., and the like can be used.
The ring-opening polymer of the cyclic olefin or the hydrogenated product thereof is usually obtained by subjecting one or more of the cyclic olefins to metathesis polymerization (ring-opening polymerization) using a molybdenum compound or a tungsten compound as a catalyst. The polymer obtained can be further hydrogenated. Such ring-opened polymers of cyclic olefins or hydrogenated products thereof are commercially available. For example, “Arton” manufactured by JSR Corporation, “Zeonex” manufactured by Nippon Zeon Co., Ltd., “Zeonor”, and the like can be used.
The amorphous cyclic olefin polymer is not particularly limited, but a cyclic olefin copolymer is more preferable. When a cyclic olefin copolymer is mixed with a polyolefin-based resin, a heat-shrinkable cylindrical label having high mixing properties and compatibility with the polyolefin-based resin and excellent transparency and impact resistance can be obtained.
The glass transition temperature (Tg) of the amorphous cyclic olefin polymer is not particularly limited, but is preferably 50 to 80 ° C., more preferably 60 to 80 ° C., and still more preferably 60 to 75 from the viewpoint of stretchability. ° C, most preferably 65 to 75 ° C (particularly about 70 ° C). The glass transition temperature of the amorphous cyclic olefin-based polymer can be adjusted by the type of monomer component (for example, cyclic olefin) and the blending ratio thereof.
When the amorphous cyclic olefin polymer is a cyclic olefin copolymer, the content of the structural unit derived from the cyclic olefin (for example, norbornene) in the cyclic olefin copolymer is not particularly limited. From the viewpoint of shrinkability, the amount is preferably 50 to 75% by mass, more preferably 60 to 70% by mass, based on the total mass (100% by mass) of the cyclic olefin copolymer and the like. For example, the norbornene content in the cyclic olefin copolymer is preferably in the above range.

The content of the main component resin in the surface layer and the back layer is not particularly limited, but is independently preferably 50% by mass or more, more preferably more than 50% by mass, based on the total mass (100% by mass). More preferably, it is 60% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more. The upper limit of the content is not particularly limited, and may be 100% by mass. For example, it is preferable that the surface layer and the back layer independently include 50% by mass or more of the polyester-based resin, more preferably more than 50% by mass with respect to the total mass (100% by mass). It preferably contains 60% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more of a polyester resin.
The content of the main component resin of the first resin layer is not particularly limited, but is preferably 50% by mass or more, more preferably more than 50% by mass, with respect to the total mass (100% by mass) of the first resin layer. More preferably, it is 55 mass% or more, Most preferably, it is 60 mass% or more. The upper limit of the content is not particularly limited, and may be 100% by mass. For example, the first resin layer preferably contains 50% by mass or more of polystyrene-based resin with respect to the total mass (100% by mass), more preferably exceeds 50% by mass, and further preferably 55% by mass. As described above, particularly preferably, it contains 60% by mass or more of polystyrene-based resin.
The content of the main component resin of the second resin layer is not particularly limited, but is preferably 50% by mass or more, more preferably more than 50% by mass with respect to the total mass (100% by mass) of the second resin layer. More preferably, it is 55 mass% or more, Most preferably, it is 60 mass% or more. The upper limit of the content is not particularly limited, and may be 100% by mass. For example, the second resin layer contains a polyethylene resin and a polystyrene resin, and preferably contains 50% by mass or more, more preferably 50% by mass of the polyester resin with respect to the total mass (100% by mass). %, More preferably 55% by mass or more, particularly preferably 60% by mass or more of a polyester resin.
Although not particularly limited, at least one of the first resin layer and the second resin layer is a styrene-conjugated diene copolymer in which the content of a structural unit derived from a conjugated diene is 20 to 50% by mass. It is preferable to contain 25% by mass or more of the entire layer. In the present specification, the “styrene-conjugated diene copolymer in which the content of the structural unit derived from the conjugated diene is 20 to 50% by mass” may be referred to as “specific styrene-conjugated diene copolymer”. is there. When at least one of the first resin layer and the second resin layer contains the specific styrene-conjugated diene copolymer, the interlayer strength at 90 ° C. at the interface between the first resin layer and the second resin layer is further improved. preferable. In this case, 25% by mass or more of the styrene-conjugated diene copolymer in which the content of the structural unit derived from the conjugated diene in the first resin layer and / or the second resin layer is 20 to 50% by mass is based on the entire layer. The styrene-diene copolymer other than the specific styrene-conjugated diene copolymer may be used in combination, and all of the styrene-diene copolymers in the first resin layer or the second resin layer may be used. Although the content of the structural unit derived from the conjugated diene with respect to the total mass (100% by mass) may be adjusted to 20 to 50% by mass, the former is preferable.

When either the first resin layer or the second resin layer is a layer containing a polystyrene resin as a main component resin, the specific styrene-conjugated diene copolymer may be used as the main component polystyrene resin. Good. On the other hand, when either one of the first resin layer or the second resin layer is a layer containing a polyester resin or a polyolefin resin as a main component resin, the specific styrene-conjugated diene copolymer is used as the main component resin. Can be used in addition to.
When at least one of the first resin layer and the second resin layer contains the specific styrene-conjugated diene copolymer in an amount of 25% by mass or more of the entire layer, the combination of the first resin layer and the second resin layer is particularly limited. However, it is preferably any of the following (i) to (iii). (I) a layer containing a specific styrene-conjugated diene copolymer as a main component and containing the copolymer in an amount of 50% by mass or more of the whole layer, and a layer containing a polyester resin or a polyolefin resin as a main component; (ii) A layer containing a polyester resin as a main component and containing a specific styrene-conjugated diene copolymer in an amount of 25% by mass or more of the whole layer, and a layer containing a polystyrene resin or a polyolefin resin as a main component (more preferably, a polystyrene resin And (iii) a layer containing a polyolefin resin as a main component and containing a specific styrene-conjugated diene copolymer in an amount of 25% by mass or more of the whole layer, and a polyester resin or a polystyrene resin as a main component. Layer (more preferably, a layer mainly composed of a polystyrene-based resin). In addition, in said (i)-(iii), both the 1st resin layer and the 2nd resin layer may contain 25 mass% or more of specific styrene-conjugated diene copolymer of each whole layer. . Among them, a layer containing a specific styrene-conjugated diene copolymer as a main component and containing the copolymer in an amount of 50% by mass or more of the whole layer, and a layer containing a polyester resin or a polyolefin resin in an amount of 90% by mass or more of the whole layer Or a layer containing a specific styrene-conjugated diene copolymer as a main component and containing the copolymer in an amount of 50% by mass or more of the whole layer, and a polyester resin or a polyolefin resin in an amount of 50% by mass or more of the whole layer. A combination of layers containing and containing a specific styrene-conjugated diene copolymer at 25% by mass or more of the whole layer is particularly preferred.

  In the specific styrene-conjugated diene copolymer, the content of the structural unit derived from the conjugated diene is 20-50% by mass with respect to the total mass (100% by mass) of the styrene-conjugated diene copolymer. It refers to a conjugated diene copolymer. However, the content of the structural unit derived from the conjugated diene is not particularly limited, but is more preferably 20 to 45% by mass with respect to the total mass (100% by mass) of the styrene-conjugated diene copolymer. Preferably it is 20-40 mass%. On the other hand, in the specific styrene-conjugated diene copolymer, the content of the structural unit derived from the styrene monomer is not particularly limited, but is based on the total mass (100% by mass) of the styrene-conjugated diene copolymer. 50 to 80% by mass, more preferably 55 to 80% by mass, particularly preferably 60 to 80% by mass. When the content of the structural unit derived from the conjugated diene is 20% by mass or more, the heat-shrinkable cylindrical label can ensure a certain flexibility, and the interlayer strength at 90 ° C. tends to be further improved. preferable. When the content of the structural unit derived from the conjugated diene is 50% by mass or less, it is possible to prevent the heat-shrinkable cylindrical label from becoming too soft and the rigidity from being lowered, which is preferable.

When at least one of the first resin layer and the second resin layer contains a specific styrene-conjugated diene copolymer, the content of the specific styrene-conjugated diene copolymer in the first resin layer or the second resin layer is Although not particularly limited, it is preferably 25% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more with respect to the total mass (100% by mass) of the first resin layer or the second resin layer. is there. When the content is less than 25% by mass, the effect of containing the specific styrene-conjugated diene copolymer may not be obtained.
When the first resin layer and / or the second resin layer is a layer mainly composed of a polystyrene-based resin, the upper limit of the content of the specific styrene-conjugated diene copolymer is not particularly limited, but the first resin layer or 100 mass% may be sufficient with respect to the total mass (100 mass%) of a 2nd resin layer, 95 mass% may be sufficient, and 90 mass% may be sufficient.

When the first resin layer and / or the second resin layer is a layer mainly composed of a polyester resin or a polyolefin resin, the upper limit of the content of the specific styrene-conjugated diene copolymer is not particularly limited, The content may be less than the content of the polyester resin or polyolefin resin as the main component of the first resin layer or the second resin layer.
The surface layer, the back layer, the first resin layer, and the second resin layer are within a range that does not impair the effects of the present invention, and are rosin resin, hydrogenated rosin resin, terpene resin, terpene-phenol resin, hydrogenated terpene. Resin, coumarone resin, hydrogenated coumarone resin, petroleum resin and other tackifying resins; aromatic hydrocarbon resins; phenolic resins; alicyclic hydrocarbon resins; styrene-acrylic copolymers, etc. May be.
In addition, the surface layer, the back layer, the first resin layer, and the second resin layer are within a range that does not impair the effects of the present invention, a lubricant, a filler, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, You may contain additives, such as an antifogging agent, a flame retardant, a coloring agent, a pinning agent (alkaline earth metal), and a softening agent. Moreover, the surface layer, the back layer, the first resin layer, and the second resin layer may contain a recovered raw material obtained by re-pelletizing a film piece at the time of film production.

The interlayer strength at 90 ° C. of the first resin layer and the second resin layer is preferably larger than the shrinkage stress at 90 ° C. of the heat-shrinkable cylindrical label. Since the interlayer strength is larger than the shrinkage stress at 90 ° C. of the heat-shrinkable cylindrical label, the first resin layer and the second resin layer are delaminated during the heat-shrinking process regardless of the interlayer strength at normal temperature. It is difficult, and the end surface of the first side end portion of the seal portion can be a good inclined surface.
The interlayer strength at 90 ° C. of the first resin layer and the second resin layer is not particularly limited, but is preferably 2N or more (for example, 2 to 8N), more preferably 3N or more (for example, 3 to 8N). When the interlayer strength is 2N or more, the interlayer strength at the time of heat shrink processing is improved, which is preferable. The interlayer strength can be adjusted, for example, by appropriately setting materials for forming the first resin layer and the second resin layer.
The interlaminar strength at 90 ° C. can be obtained, for example, by measuring the delamination strength in the 180 ° direction in a state heated to 90 ° C. in accordance with JIS K6854-2. Specifically, it can be measured by the following method.
On the end surface of the laminated film, the film is partially peeled at the interface between the first resin layer and the second resin layer to form a peeled portion (peeled portion) and a peeled portion (peeled portion). This part to be peeled is fixed to a glass plate using an adhesive tape. Then, it heats to 90 degreeC from the glass plate side. Then, the glass plate is fixed so as not to move, and the peeling portion is pulled in the 180 ° direction at a pulling speed of 200 mm / min. The strength at the time of pulling is measured, and the strength is defined as the interlayer strength at 90 ° C. at the interface between the first resin layer and the second resin layer. In addition, let the thin side of the film when peeling be a peeling part, and let the thick side be a to-be-peeled part.
The interlayer strength at normal temperature (23 ° C.) of the first resin layer and the second resin layer is not particularly limited, but is preferably 0.1 to 1.5N, more preferably 0.1 to 1.0N, and 0.2 to 0.8N is more preferable. The interlayer strength at normal temperature can be obtained by measuring by a T-type peel test at normal temperature in accordance with JIS K6854-3. Specifically, the laminated film is cut into a width of 15 mm and a length of 200 mm to produce a sample piece for measurement, and at the end face of this sample piece, partly peeled off at the interface between the first resin layer and the second resin layer Then, a peeled part (peeling part) and a part remaining after peeling (peeled part) are formed. The peeled portion and the peeled portion are each held by a chuck, and are pulled at a pulling speed of 200 mm / min in opposite directions at room temperature, and the strength at that time is measured.

Although the shrinkage stress in 90 degreeC of a heat-shrinkable cylindrical label is not specifically limited, 1-7N are preferable, More preferably, it is 1-5N, More preferably, it is 1-3N. The heat-shrinkable cylindrical label having a shrinkage stress of 1N or more improves the followability to the adherend. The shrinkage stress can be adjusted, for example, by appropriately setting the thickness, layer configuration, forming material, and the like of the laminated film.
The shrinkage stress is obtained by, for example, measuring stress generated in a laminated film when both ends of the laminated film are fixed and immersed in hot water at 90 ° C., for example, “Shimadzu Autograph (AGS manufactured by Shimadzu Corporation)”. −50G: load cell type 500 N) ”).

Although the thickness (total thickness) of the said laminated | multilayer film is not specifically limited, 10-100 micrometers is preferable, More preferably, it is 15-50 micrometers, More preferably, it is 20-45 micrometers. When the thickness of the laminated film is 10 μm or more, it has a necessary strength as a label for machine mounting. When the thickness is 100 μm or less, the shrinkage stress of the laminated film can be further reduced.
Although the thickness of the surface layer and back layer of a laminated film is not specifically limited, 1-15 micrometers is preferable each independently, More preferably, it is 2-10 micrometers, More preferably, it is 2.5-8 micrometers. When the thickness of the surface layer and the back layer exceeds 15 μm, delamination may occur between the surface layer, the back layer and the intermediate layer. When the thickness of the surface layer and the back layer is less than 1 μm, the rigidity of the label may decrease.
Although the thickness of the intermediate | middle layer of a laminated | multilayer film is not specifically limited, 8-90 micrometers is preferable, More preferably, it is 10-45 micrometers, More preferably, it is 11-40 micrometers.
The thickness of each resin layer constituting the intermediate layer is not particularly limited, but is preferably 0.2 μm or more (for example, 0.2 to 10 μm), more preferably 0.3 μm or more (for example, 0.3 to 5 μm). It is. Each resin layer constituting the intermediate layer may have the same thickness or a part of the thickness, or may be different from each other. For example, among the resin layers constituting the intermediate layer, the thickness of the resin layer in contact with the surface layer and the back layer may be smaller than the thickness of the resin layer constituting the other intermediate layer.
The ratio of the thickness of the surface layer to the thickness of the intermediate layer (surface layer thickness: intermediate layer thickness) is not particularly limited, but is preferably 1: 1 to 1:10, more preferably 1: 1 to 1: 4. The ratio of the thickness of the back layer to the thickness of the intermediate layer is the same as the ratio of the thickness of the surface layer to the thickness of the intermediate layer.

The laminated film can be produced, for example, as follows.
The laminated film can be produced by a conventional method such as melt film formation. Among these, the melt film forming method (particularly, the T-die method) is preferable. As a lamination method, a conventional method such as a co-extrusion method (feed block method, multi-manifold method, etc.), a dry lamination method, or the like can be used. Among them, the coextrusion method is preferable, the feed block method is more preferable, and the method of combining the feed block and the layer multiplier is more preferable. The layer multiplier is an apparatus for multilayering film layers. The method of multi-layering with the layer multiplier is not particularly limited, but after dividing one film layer in the width direction, the two divided film layers are laminated in the thickness direction, and this is performed as necessary. The method of repeating is mentioned. Hereinafter, the layer multiplier may be simply referred to as a multiplier. The multiplier can be obtained from, for example, EDI Corporation or Crawlen Corporation.

In the co-extrusion method (feed block method), a resin material (1) for forming the first resin layer and a resin material (2) for forming the second resin layer are placed in a plurality of extruders each set to a predetermined temperature. And melt extrusion (coextrusion) from a T die, a circular die or the like. In addition, extrusion temperature is suitably set according to the kind of resin material to be used. The molten resin materials (1) and (2) are respectively extruded from the feed block to produce a first laminate of resin material (1) / resin material (2) / resin material (1), and this first laminate The unit is stacked using a multiplier, and the resin material (1) / resin material (2) / resin material (1) × 2 / resin material (2) / resin material (1) A 2nd laminated body is produced. A surface layer / first resin layer / second resin layer / first resin layer × 2 / second resin is formed by extruding a surface layer forming material and a back layer forming material from both sides of the second laminated body through a feed block. A laminated unstretched film of 7 layers of layer / first resin layer / back layer is obtained. Note that, due to the lamination, the interface where the two layers of the resin material (1) indicated as “resin material (1) × 2” overlap cannot be recognized and becomes one layer of the resin material (1).
The obtained laminated unstretched film is stretched. For the stretching treatment, biaxial stretching in the longitudinal direction (MD direction) and width direction (TD direction), uniaxial stretching in the longitudinal direction or width direction, and the like can be used. As the stretching method, any of a roll method, a tenter method, and a tube method may be used. For example, after stretching at a stretching temperature of 65 to 100 ° C. and a stretching ratio of 1.05 to 1.50 times in the longitudinal direction by a roll method, a stretching temperature of 70 to 100 ° C. and a stretching ratio of 3 to 7 times in the width direction by a tenter method ( Preferably, the film is stretched by 4 to 5.5 times.
By performing the stretching treatment, the laminated film can be obtained.
In addition, although the said manufacturing method illustrated the case where the laminated film of a total of 7 layers which consists of a surface layer, a 5 layer intermediate | middle layer, and a back layer was manufactured, the 1st laminated body which is 1 unit was laminated | stacked using a multiplier. After the second laminated body is formed, a laminated film composed of eight or more layers is obtained by repeating this a predetermined number of times.

(Heat-shrinkable cylindrical label after heat-shrinking)
FIG. 5 shows the heat-shrinkable cylindrical label attached to the adherend, and FIG. 6 shows the seal portion of the heat-shrinkable cylindrical label.
The heat-shrinkable cylindrical label 1 before the heat-shrinking process is expanded in a cylindrical shape, and is externally fitted on the adherend 8 and then heated to a required temperature, thereby being thermally contracted in the circumferential direction.
Examples of the heating method include a method of passing through a hot air tunnel or a steam tunnel, a method of heating with radiant heat such as infrared rays, and the like. In particular, a method of treating with steam at 80 to 100 ° C. (passing through a heating tunnel filled with steam and steam) is preferable. Moreover, 101-140 degreeC dry steam can also be used. Although the said heat processing is not specifically limited, It is preferable to implement in the temperature range from which the temperature of a heat-shrinkable cylindrical label will be 85-100 degreeC (especially 90-97 degreeC). The heating time is preferably 4 to 20 seconds from the viewpoint of productivity and economy.
Although the said adherend 8 is not specifically limited, Typically, containers, such as a container for drinks as shown in FIG. 5, are mentioned.
In such a heat-shrinked state, the heat-shrinkable cylindrical label 10 is an inclined surface in which the end surface 21a of the first side end portion 21 of the seal portion 3 is inclined.
The end surface 21 a of the first side end portion 21 is inclined at an acute angle with respect to the back surface 21 b of the first side end portion 21.
The inclined surface is formed at least on the end surface of the alternately laminated portion 7, and preferably formed over the entire end surface 21 a of the first side end portion 21.

FIG. 7 is a further enlarged cross-sectional view (a cross-sectional view in which the seal portion of FIG. 6 is further enlarged) illustrating in detail one form of the end face of the first side end portion, and FIG. 8 is a view of the first side end portion. FIG. 7 is a further enlarged cross-sectional view illustrating another form of the end face in detail (a cross-sectional view in which the seal portion in FIG. 6 is further enlarged). FIG. 7 and FIG. 8 both show the end face of the first side end portion. It is shown visually.
The form of the end face of the first side end in FIG. 7 is when the end faces of the surface layer, the back layer, and the first and second resin layers are cut in the thickness direction along the circumferential direction of the heat-shrinkable cylindrical label. In the cross-sectional view, it forms an arc shape, and the shape of the end surface of the first side end portion in FIG. 8 is that the end surfaces of the first and second resin layers are in the thickness direction along the circumferential direction of the heat-shrinkable cylindrical label. It is straight when viewed in section when cut. 7 and 8 differ in this respect. On the other hand, the end surface of the first side end portion in FIG. 7 and the end surface of the first side end portion in FIG. 8 are all formed by connecting the end surfaces of the surface layer, the first and second resin layers, and the back layer. It is common in the point which is a surface, and it is common by the preferable structure that all are the inclined surfaces dented inward.

In FIG. 6 seen macroscopically, the end surface 21a of the first side end portion 21 including the end surfaces of the alternately laminated portions 7 is connected to the end surfaces 6a, 5a, 4a of the back layer 6, the intermediate layer 5, and the surface layer 4. One inclined surface is formed, and the inclined surface forms an acute angle with respect to the back surface 21b of the first side end portion 21 as described above. The end surfaces Aa, Ba of the first and second resin layers A, B constituting the alternate laminated portion 7 are also connected to form one acute inclined surface. The end surface 21a of the first side end portion 21 may be an inclined surface recessed inward as shown in FIG. 6 in a cross-sectional view when cut in the thickness direction along the circumferential direction. A swollen inclined surface or a linear inclined surface may be used.
In the present specification, the inclined surface recessed inward is based on a virtual straight line connecting the front end and the back end of the inclined surface in a cross-sectional view when cut in the thickness direction along the circumferential direction. In other words, the inclined surface does not substantially exceed the virtual straight line (in other words, a shape in which a gap is generated between the virtual straight line and the inclined surface). A shape that exceeds a straight line (in other words, a shape in which the material for forming each layer is filled between the virtual straight line and the inclined surface). The end surface 21a of the first side end portion 21 shown in FIG. 6 is an inclined surface that is recessed inwardly, which is substantially a virtual straight line connecting the front end 4X of the surface layer 4 and the front end 6Y of the back layer 6. It is not over. Note that “the inclined surface does not substantially exceed the virtual straight line” means that the inclined surface does not strictly exceed the virtual straight line, or if the inclined surface is partly in contact with the virtual straight line. This means that there are places where a part of the line exceeds the imaginary straight line, but the part beyond that is negligible when viewed from the whole.
When the end surface 21a of the first side end portion 21 is not a linear inclined surface, the inclined surface is preferably arcuate.
When the end surface 21a of the first side end portion 21 is an arc-shaped inclined surface, as shown in FIG. 6, an arc shape recessed inward may be used, and although not particularly illustrated, an arc shape bulging outward may be used.
In this specification, the inclination angle of the inclined surface (end surface) refers to an angle (acute angle) formed by the inclined surface and the back surface of the first side end, and when the inclined surface is arcuate, the inclination angle is: An angle formed between a tangent at an arbitrary point on the inclined surface and the back surface of the first side end.

In FIG. 7 viewed microscopically, the end surfaces Aa and Ba of the first and second resin layers A and B are inclined surfaces inclined at an acute angle with respect to the back surface 21b of the first side end portion 21, respectively. The inclined surface is preferably recessed inward, and more preferably is an arcuate inclined surface recessed inward. Further, the end surfaces 6a and 4a of the back layer 6 and the surface layer 4 are also inclined surfaces inclined at an acute angle with respect to the back surface 21b of the first side end portion 21, and are preferably recessed inward and more preferably inward. It is an arcuate inclined surface that is recessed.
Each end surface Aa, Ba, 6a, 4a may be an inclined surface bulging outward or an arcuate inclined surface bulging outward, but is preferably an inclined surface recessed inward as shown.
Regarding the inclined surface recessed inward, for example, the end surface A of the first resin layer A shown in FIG. 7 does not exceed the virtual straight line connecting the front end AX and the back end AY of the resin layer A.
The inclination angles of the end faces Aa and Ba of the first and second resin layers A and B may be the same or different. Preferably, among the first and second resin layers A and B constituting the alternately laminated portion 7, the inclination angles of the end surfaces Aa and Ba between the adjacent first resin layer A and the second resin layer B are preferable. Has a changing part. More preferably, the inclination angles of the end faces Aa and Ba are changed between all adjacent first resin layers A and second resin layers B constituting the alternately laminated portion 7. The change in the inclination angle includes that the inclination angle of each of the end faces Aa and Ba becomes larger toward the surface side of the first side end portion 21. Specifically, the inclination angle of the end surface Aa of the first resin layer A in the vicinity of the back side of the front end AX of the first resin layer A is relatively large, but the second resin layer B in the vicinity of the front side of the front end AX The inclination angle of the end face Ba is smaller than the inclination angle of the end face Aa of the first resin layer A in the vicinity of the back side, and the end faces Aa of the first resin layer A and the second resin layer B with the tip AX in between. The inclination angle of Ba changes.
The end surface 6a of the back layer 6 and / or the end surface 4a of the surface layer 4 may be linearly inclined surfaces, but preferably, the end surface 6a of the back layer 6 and / or the end surface 4a of the surface layer 4 are inside as shown in the figure. It is an inclined surface that is recessed.
For each end surface, the end surface Aa of the first resin layer A has an inclination angle that increases toward the surface side of the first side end portion 21, and the end surface Ba of the second resin layer B similarly has the first side end. The inclination angle increases toward the surface side of the portion 21. Even when the end surface 6a of the back layer 6 and the end surface 4a of the surface layer 4 are arc-shaped inclined surfaces, the inclination angle increases toward the surface side of the first side end portion 21, respectively.

Since the back surface 21b of the back layer 6 of the first side end portion 21 is bonded to the second side end portion 22 in the seal portion 3 and the shrinkage of the back surface side of the back layer 6 is restricted during heat shrink processing, there is a difference in shrinkage between the front and back sides. The end surface 6a of the back layer 6 becomes an inclined surface. Similarly, the first and second resin layers A and B and the surface layer 4 of the intermediate layer 5 (alternately laminated portion 7) also cause shrinkage differences between the front and back surfaces, so that the end surfaces Aa, Ba, and 4a are inclined surfaces. . Since the number of layers of each layer 6, Aa, Ba, 4 decreases toward the surface side of the first side end portion 21, the shrinkage difference between the front and back of each layer gradually decreases, and the inclination angle of the end surface 6a of the back layer 6 becomes smaller. The inclination angle of the end surface 4a of the surface layer 4 is the smallest, and the inclination angle of the end surfaces Aa, Ba of the first and second resin layers A, B changes continuously.
The end surfaces Aa, Ba of the adjacent first and second resin layers A, B are continuous at the boundary, respectively, the end surface 6a of the adjacent back layer 6, the end surface Aa of the first resin layer A, and the adjacent surface layer. The end face 4a of 4 and the end face Aa of the first resin layer A are also continuous at the boundary.
In addition, in the present embodiment in which each end surface 4a, Aa, Ba, 6a is an inclined surface recessed inward, the end surface 21a of the first side end portion 21 can be said to be stepped microscopically. Macroscopically, as shown in FIG. 6, a plurality of end faces 4a, Aa, Ba, 6a are continuously formed as one inclined surface.

On the other hand, in FIG. 8 viewed microscopically, the end surfaces Aa and Ba of the first and second resin layers A and B are linear with acute angles with respect to the back surface 21b of the first side end portion 21, respectively. It is assumed to be an inclined surface. Further, the end surfaces 6 a and 4 a of the back layer 6 and the surface layer 4 are also linear inclined surfaces that form an acute angle with respect to the back surface 21 b of the first side end portion 21.
The inclination angles of the end faces Aa and Ba of the first and second resin layers A and B may be the same or different. Preferably, among the first and second resin layers A and B constituting the alternately laminated portion 7, the inclination angles of the end surfaces Aa and Ba between the adjacent first resin layer A and the second resin layer B are preferable. Has a changing part. More preferably, the inclination angles of the end faces Aa and Ba are changed between all adjacent first resin layers A and second resin layers B constituting the alternately laminated portion 7. The change in the inclination angle includes that the inclination angle of each of the end faces Aa and Ba becomes larger toward the surface side of the first side end portion 21.
The end surface 6a of the back layer 6 and / or the end surface 4a of the surface layer 4 may be an inclined surface recessed inward, but preferably the end surface 6a of the back layer 6 and / or the end surface 4a of the surface layer 4 is a linear inclined surface. It is.
Also in the case of FIG. 8, the back layer 6, the first and second resin layers A and B, and the front layer 4 cause shrinkage differences between the front and back during the heat shrink processing, so that the end surfaces 6 a, Aa, Ba, and 4 a are inclined. It becomes a surface.
The end surfaces Aa, Ba of the adjacent first and second resin layers A, B are continuous at the boundary, respectively, the end surface 6a of the adjacent back layer 6, the end surface Aa of the first resin layer A, and the adjacent surface layer. The end face 4a of 4 and the end face Aa of the first resin layer A are also continuous at the boundary.
Further, in the present embodiment in which the end surfaces Aa, Ba, 6a, and 4a are linearly inclined surfaces, the end surface 21a of the first side end portion 21 can be said to be polygonal microscopically, but macroscopically. As shown in FIG. 6, a plurality of end surfaces Aa, Ba, 6a, 4a are continuously formed as one inclined surface.

When viewed microscopically as shown in FIGS. 7 and 8, the front-side tip and the back-side tip of each adjacent layer coincide with each other, but they may be slightly shifted. In particular, between the back layer 6 and the first resin layer A adjacent thereto, and / or between the first resin layer A adjacent to the back layer 6 and the second resin layer B adjacent thereto, the tips of both layers May be slightly off. An example of such a case is shown in FIG. In FIG. 8, the back layer 6 and the first resin layer A are adjacent to each other, but the front end 6X of the back layer 6 and the back end AY of the first resin layer A are slightly shifted. Thus, a slight step is formed at the front end 6X of the back layer 6. The first resin layer A is adjacent to the second resin layer B, and the front end AX of the first resin layer A and the front end BY of the second resin layer B are slightly shifted. Due to this, a slight step is formed at the front end AX of the first resin layer A. Even when such a step is formed, the end surface 21a of the first side end portion 21 forms one inclined surface as a whole. In addition, a level | step difference surface shall be included in the end surface of the layer which has produced the level | step difference notionally. For example, the step surface between the tip AY and the tip 6X is included in the end surface 6a of the back layer 6, and the step surface between the tip BY and the tip AX is included in the end surface Aa of the first resin layer A. .
In this case, for example, with the front end BY on the back side of the second resin layer B as a boundary, the inclination angle of the end surface Ba of the second resin layer B is larger than the inclination angle of the step surface (end surface Aa of the first resin layer A). It is large and has a portion where the inclination angles of the end faces Aa and Ba change between the adjacent first resin layer A and second resin layer B.
FIG. 7 illustrates a case where all end surfaces 4a, Aa, Ba, 6a form an inclined surface recessed inward, and in FIG. 8, all end surfaces 4a, Aa, Ba, 6a are linear. However, the present invention is not limited to this. For example, at least one selected from the end faces 4a, Aa, Ba, and 6a is an inclined face that is recessed inward, and each end face. At least one selected from 4a, Aa, Ba, and 6a may be a linear inclined surface (not shown), and each of the end surfaces 4a, Aa, Ba, and 6a has the above-described various inclined surface shapes. It may be mixed.

Since the first side end portion 21 of the seal portion 3 is located on the surface side of the heat-shrinkable cylindrical label 10, it is easy to come into contact with foreign matter. However, the heat-shrinkable cylindrical label 10 of the present invention has a seal portion. Since the end surface 21a of the first side end portion 3 is an inclined surface, it can be peeled off between the resin layers of the laminated film even if it is in contact with adjacent containers or in contact with mechanical devices. Can be effectively prevented.
In addition, in the alternately laminated portion 7 in which resin layers (first resin layer A and second resin layer B) having different main component resins are alternately laminated, the resin layers A and B are usually easily delaminated. In the heat-shrinkable cylindrical label 10 of the present invention, since the first resin layer A and the second resin layer B have the alternately laminated portions 7 in which 5 layers or more (preferably 7 layers or more) are laminated, the alternately laminated portions are provided. 7 is relatively thin, the shrinkage stress of the resin layers A and B during heat shrink processing is dispersed, and the interlayer between the first resin layer A and the second resin layer B is It can prevent peeling. In particular, when the main resin of the first resin layer A is a polyester resin and the main resin of the second resin layer B is a polystyrene resin, the main resin of the first resin layer A is a polyolefin resin and the first resin When the main resin of the second resin layer B is a polystyrene resin, or when the main resin of the first resin layer A is a polyester resin and the main resin of the second resin layer B is a polyolefin resin The delamination of the resin layers can be effectively prevented.
As described above, the heat-shrinkable cylinder of the present invention has a synergistic effect that the resin layers are hardly separated from each other and the end surface 21a of the first side end portion 21 that may be twisted is an inclined surface. As for the shape label 10, it becomes difficult to spill part of a film in the seal part 3. FIG. The labeled container in which the heat-shrinkable cylindrical label 10 is mounted on the container has a good appearance and the heat-shrinkable cylindrical label 10 is not easily broken.

The heat-shrinkable cylindrical label of the present invention is not limited to the above embodiment, and can be variously modified within the scope intended by the present invention.
For example, in the above-described embodiment, the alternately laminated portions are provided in the intermediate layer, but the alternately laminated portions may be provided in the surface layer and the intermediate layer, or provided in the intermediate layer and the back layer. Also good. In the former case, the surface layer may be the first resin layer or the second resin layer. For example, when the surface layer is composed of the first resin layer, the first resin layer (surface layer) / second An alternately laminated portion of two resin layers (a part of the intermediate layer) / first resin layer (a part of the intermediate layer) is formed. In the latter case, the back layer may be the first resin layer or the second resin layer. For example, when the back layer is composed of the first resin layer, the first resin layer (the back layer is sequentially formed from the back side). ) / Second resin layer (part of the intermediate layer) / first resin layer (part of the intermediate layer) /... Moreover, the alternating lamination part may be provided over the whole laminated film. In this case, the surface layer and the back layer may be either the first resin layer or the second resin layer. For example, the first resin layer (surface layer) / second resin layer (part of the intermediate layer) / first resin layer (Part of the intermediate layer) /.../ first resin layer (part of the intermediate layer) / second resin layer (part of the intermediate layer) / first resin layer (back layer) are alternately laminated, This is a laminated film.
Among them, preferred is a laminated film in which all of the alternately laminated portions are included in the intermediate layer, and the main component resin of the front layer and the back layer is the same system resin as the main component resin of the intermediate layer resin layer in contact with them, More preferable is a laminated film in which the entire intermediate layer is composed of alternately laminated portions, and the main component resin of the front layer and the back layer is the same type of resin as the main component resin of the resin layer of the intermediate layer in contact therewith.

DESCRIPTION OF SYMBOLS 1,10 Heat-shrinkable cylindrical label 2 Laminated | multilayer film 21 1st side edge part 21a End surface of 1st side edge part 22 2nd side edge part 3 Sealing part 4 Surface layer 5 Intermediate | middle layer 6 Back layer 7 Alternating laminated part A 1st Resin layer B Second resin layer

Claims (5)

The back surface of the first side end portion of the heat-shrinkable base material is superposed on the surface of the second side end portion, and is formed into a cylindrical shape by bonding the overlapping surfaces to form a seal portion.
The heat-shrinkable substrate includes a heat-shrinkable laminated film having 7 or more resin layers,
The laminated film has a surface layer, an intermediate layer, and a back layer, and the intermediate layer is formed by alternately laminating first resin layers and second resin layers having different resin components, and the first resin layer and the second resin layer. Including a total of five or more alternating laminated parts,
The surface layer is a resin layer mainly composed of a polyester-based resin,
A heat-shrinkable cylinder in which at least the end surface of the alternately laminated portion is an inclined surface inclined at an acute angle with respect to the back surface of the first side end portion in the state of heat shrink processing. Label. The heat-shrinkable cylindrical label according to claim 1, wherein the main component resin of the surface layer and the main component resin of the back layer are the same . The back layer is a resin layer mainly composed of a polyester-based resin,
The first resin layer of the intermediate layer is a resin layer mainly composed of a polyester resin, and the second resin layer of the intermediate layer is a resin layer mainly composed of a polystyrene resin or a polyethylene resin . The heat-shrinkable cylindrical label according to claim 1 or 2. Each of the end surfaces of the surface layer, the back layer, the first resin layer, and the second resin layer is an inclined surface inclined at an acute angle with respect to the back surface of the first side end portion, respectively.
The inclination angle of the end surface of the surface layer is the largest, and the inclination angle of the end surface of the back layer is the smallest,
Furthermore, the heat-shrinkable cylindrical label as described in any one of Claims 1 thru | or 3 which has a part from which the inclination | tilt angle of those end surfaces changes between adjacent 1st resin layer and 2nd resin layer .   The step is formed between the end surface of the back layer and the end surface of the resin layer adjacent to the back layer, or between the end surface of the adjacent first resin layer and the end surface of the second resin layer. The heat-shrinkable cylindrical label as described in 2.

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