JP5184817B2 - Shrink label - Google Patents

Description

  The present invention is a shrink film using a polylactic acid-based polymer that is a plant-derived raw material, and a shrink label having a printed layer (hereinafter simply referred to as “shrink film” or “shrink label” unless otherwise noted) It may mean both shrink film and shrink labels made of it and having a printed layer).

  Currently, plastic bottles such as PET bottles and metal bottles such as bottle cans are widely used as containers for beverages such as tea and soft drinks. For these containers, plastic labels such as shrink labels are widely used for providing display, decoration, and functionality.

  As the shrink label, in recent years, a film using polylactic acid which is biodegradable and plant-derived material has been studied from the viewpoint of environmental protection (for example, see Patent Document 1). Moreover, in order to improve the impact resistance and seal strength of a polylactic acid film, a laminated shrink film having a polylactic acid polymer and a polyester resin is known (see, for example, Patent Documents 2 and 3).

  However, in the shrink film containing polylactic acid, the shrinkage rate at the time of thermal shrinkage is much higher than that of existing shrink film such as polystyrene film and polyester film because of the inherent property of polylactic acid. Since this occurs abruptly, it is difficult to control the shrinkage behavior at the time of heat shrinking, and the appearance of the label after heat shrinking is often impaired. In particular, when the heat shrinkage rate varies greatly depending on the site, such as in the case of beverage bottles, there are problems such as `` wrinkles '' or non-uniform heat shrinkage resulting in poor design as a label. It was happening.

  Thus, there is a demand for a shrink film having an appropriate heat shrinkability, and in particular, from the environmental viewpoint, there is a need for a shrink film having an appropriate heat shrink rate using plant-derived polylactic acid. It is.

JP-A-5-212790 JP 2002-234117 A JP-A-2005-35238

  The object of the present invention is a shrink label using a polylactic acid-based polymer, and by improving the heat shrinkage rate of the shrink film, the shrink processability and the finish are improved, thereby improving the productivity. It is to provide a contracted shrink label.

  As a result of intensive studies to achieve the above object, the inventors of the present invention specified a heat shrinkage rate at 75 ° C. of a shrink film having a film layer containing a polylactic acid polymer as an essential component and a shrink label having a printed layer. By controlling to the range, it was found that a shrink label capable of heat shrinking at a low temperature or in a short time and having excellent finish was obtained, and the present invention was completed. Also, a laminated shrink film of a film layer mainly composed of a polylactic acid polymer and a film layer mainly composed of a polystyrene resin or an aromatic polyester resin, wherein the thickness ratio of each film layer is within a specific range. It has been found that a shrink label having the above characteristics can be obtained by controlling to the above.

That is, the present invention is a shrink label having at least one film layer (A layer) having a polylactic acid polymer as an essential component and a printed layer, wherein the shrink film further comprises a polystyrene resin. Or it is a laminated shrink film which has at least one film layer (B layer) which has resin other than the polylactic acid-type polymer which is an aromatic polyester resin as a main component, and is a film layer of all the A layers of the laminated shrink film The ratio of the thickness to the film layer thickness of all B layers (A layer thickness / B layer thickness) is 80/20 to 20/80, and the content of the polylactic acid polymer in the A layer is 50% by weight or more. In the monomer component constituting the polylactic acid polymer, the ratio of the D-lactic acid component in the total lactic acid component is 4 to 15% by weight, and the B layer A of the content of the resin other than the polylactic acid polymer from 70 to 100 wt.%, 75 ° C. main alignment direction of the heat shrinkage rate in the heat shrinkage starting one second after the in hot water 3-23%, further 90 A shrink label having a thermal shrinkage ratio in the main alignment direction at 40 ° C. for 10 seconds at 40 ° C. is provided.

The present invention also relates to a shrink label having at least one film layer (A layer) having a polylactic acid polymer as an essential component and a printed layer, wherein the shrink film further comprises a polystyrene resin. Or it is a laminated shrink film which has at least one film layer (B layer) which has resin other than the polylactic acid-type polymer which is an aromatic polyester resin as a main component, and is a film layer of all the A layers of the laminated shrink film The ratio of the thickness to the film layer thickness of all B layers (A layer thickness / B layer thickness) is 80/20 to 20/80, and the content of the polylactic acid polymer in the A layer is 50% by weight or more. In the monomer component constituting the polylactic acid polymer, the proportion of the D-lactic acid component in the total lactic acid component is 4 to 15% by weight, Serial content of the resin other than the polylactic acid polymer is from 70 to 100 wt%, the maximum heat shrinkage rate in the main orientation direction in 75 ° C. hot water 7-40% / sec, further 90 ° C., 10 A shrink label having a heat shrinkage rate in the main orientation direction in seconds of 40 to 84% is provided.

  Furthermore, the present invention provides the aforementioned shrink label, wherein the shrink film is a laminated shrink film having a B layer on both sides of the A layer or an A layer on both sides of the B layer.

The present invention also relates to a shrink label having at least one film layer (A layer) comprising a polylactic acid polymer as an essential component and a printed layer, wherein the shrink film is a single layer of the A layer. It is a layer shrink film, the content of the polylactic acid polymer in the layer A is 50% by weight or more, and the layer A is further selected from the group consisting of a polystyrene resin and an aromatic polyester resin. 10% to 50% by weight of a resin other than the polylactic acid polymer, and the proportion of the D-lactic acid component in the total lactic acid component in the monomer component constituting the polylactic acid polymer is 5% by weight or less. The content of the aromatic dicarboxylic acid component in the total dicarboxylic acid component used in the aromatic polyester resin is 60 mol% or more, and heat in 75 ° C. warm water There is provided a shrink label characterized in that the heat shrinkage rate in the main alignment direction at 1 second after the start of shrinkage is 3 to 23%, and further at 90 ° C., the heat shrinkage rate in the main alignment direction at 10 seconds is 40 to 84%. .

The present invention also relates to a shrink label having at least one film layer (A layer) comprising a polylactic acid polymer as an essential component and a printed layer, wherein the shrink film is a single layer of the A layer. It is a layer shrink film, the content of the polylactic acid polymer in the layer A is 50% by weight or more, and the layer A is further selected from the group consisting of a polystyrene resin and an aromatic polyester resin. 10% to 50% by weight of a resin other than the polylactic acid polymer, and the proportion of the D-lactic acid component in the total lactic acid component in the monomer component constituting the polylactic acid polymer is 5% by weight or less. The content of the aromatic dicarboxylic acid component in the total dicarboxylic acid component used in the aromatic polyester resin is 60 mol% or more, The shrink label is characterized in that the maximum heat shrinkage rate in the alignment direction is 7 to 40% / second, and the heat shrinkage rate in the main alignment direction at 90 ° C. for 10 seconds is 40 to 84%.

  The shrink label of this invention has little environmental impact by using the polylactic acid-type polymer which is a plant-derived raw material as an essential component. Further, by controlling the heat shrinkage rate within a certain range, problems such as “wrinkles” and “printing distortion” are less likely to occur during shrink processing, and production efficiency and finish are improved. For this reason, the shrink label of the present invention is particularly useful as a label for use in plastic containers such as PET bottles.

  Below, the shrink label of this invention is demonstrated in detail.

  The shrink label of the present invention comprises a shrink film and a printing layer as essential constituent components.

  The shrink film of the present invention only needs to have at least one film layer (hereinafter referred to as A layer) containing a polylactic acid polymer as an essential component, and may be a single layer film of A layer. Moreover, the laminated film which has at least 1 layer of film layers (henceforth B layer) which has resin other than A layer and polylactic acid-type polymer as a main component may be sufficient.

  When the shrink film of the present invention is a laminated film, a known method can be used as the laminating method, and for example, coextrusion, adhesion via an adhesive layer, dry lamination, melt extrusion lamination are possible. Etc. Of these, coextrusion is preferred from the viewpoint of the finish of heat shrink processing. The laminated structure is not particularly limited, but an A / B two-type two-layer structure or a B / A / B or A / B / A two-type three-layer structure is preferable, and heat shrink processability, chemical stability of the film. From the viewpoint of properties (weather resistance, hydrolysis resistance, etc.), a B / A / B type of two-layer structure is particularly preferable. The two A layers or the two B layers in the case of a three-layer structure may be the same film layer, but may have different compositions as long as the same kind of resin is a main component. The layer thickness may be different. Furthermore, as long as the effect of the present invention is not impaired, these film layers may be laminated via an adhesive layer (for example, B layer / adhesive layer / A layer / adhesive layer / B layer 3 type 5) Layer structure). Moreover, you may have other film layers other than A layer and B layer.

  The shrink film of the present invention is oriented in at least one direction. In the case of a laminated structure having an A layer and a B layer, at least one of the A layer and the B layer in the film is oriented in the same direction. When only one of the A layer and the B layer is oriented, or when all the layers in the film are non-oriented, good heat shrinkability cannot be obtained. Among them, it is particularly preferable that all the film layers are oriented. The orientation may be either uniaxial orientation or biaxial orientation and is not particularly limited. In the biaxial orientation, the film mainly used for labeling is generally a film that is largely oriented in either the longitudinal direction or the width direction of the film. Such a film may be oriented more strongly in the film width direction (the direction that becomes the circumferential direction when the label is made cylindrical), or more strongly oriented in the longitudinal direction of the film (the direction perpendicular to the width direction). You may do it. The former is preferred when the film is used as a cylindrical shrink label.

  The A layer of the present invention is a film layer containing a polylactic acid polymer as an essential component. Layer A may be composed of only a polylactic acid polymer, but may be a composition containing other resins, adjustment of heat shrinkage rate during shrink processing, improvement of adhesion between layers, or recovered material From the viewpoint of using, a resin used as a main component of the B layer such as a polyester resin, a polystyrene resin, or a polyolefin resin may be included. Moreover, the other additive may be included.

  The polylactic acid polymer used in the A layer of the present invention means a polymer containing lactic acid as a monomer component, and lactic acid has an optical isomer and the composition ratio of optical isomers constituting the polymer (D The physical properties of the polymer change depending on the content ratio of the body and the L body. For example, if the ratio of D body to L body is reduced, the heat shrinkage rate can be slowed, but the crystallinity of the resin increases, the rigidity of the film becomes higher than necessary, and the tactile feeling of the film deteriorates. Disadvantages such as reduced cold resistance occur. Commercially available polylactic acid-based polymers include, for example, those in which D-lactic acid accounts for about 1-2% by weight, about 4-5% by weight, or about 10-15% by weight of the total lactic acid component. The present invention covers all of them without distinguishing them. Among these, when the shrink film used in the present invention is a single layer, the viewpoint of slowing the heat shrinkage rate becomes more important. Therefore, as a polylactic acid polymer, the D-lactic acid component occupies the total lactic acid component. It is preferable to use a ratio of 5% by weight or less. On the other hand, when the shrink film used in the present invention is a laminated film, the effect of slowing the heat shrinkage rate by the B layer is added, and therefore, it is more important to consider the viewpoint of rigidity as compared with the case of a single layer. It becomes possible. For this reason, from the viewpoint of the rigidity of the film, the polylactic acid polymer preferably has a D-lactic acid component ratio of about 4 to 15% by weight, more preferably 7 to 15% by weight, based on the total lactic acid component. More preferably, it is 10 to 15% by weight. In addition, the polylactic acid-based polymer used in the A layer of the present invention is a copolymer of lactic acid and other hydroxycarboxylic acid or lactone, or a copolymer of lactic acid with other dicarboxylic acids and / or diols. Polymers are also included. 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. Examples of the dicarboxylic acid include various aliphatic (saturated and unsaturated) dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. Examples of the diol component include various aliphatic diols and alicyclic diols.

  The hydroxycarboxylic acids, lactones, dicarboxylic acids or diols exemplified here may be mixed with lactic acid in the monomer state and introduced into the polymer as a random copolymer, or an oligomer previously polymerized as a polyester. Alternatively, it may be introduced into the polymer in the form of forming a block copolymer with lactic acid as a prepolymer.

  The proportion of lactic acid in all monomers constituting the polylactic acid polymer is generally 20 mol% or more, preferably 35 mol% or more when the film is composed of a single layer A composed of a single material. Preferably it is 50 mol% or more, and particularly from the viewpoint of biodegradability, 65 mol% or more is preferred. When the film is a multilayer film in which the A layer and the B layer are combined, the proportion of lactic acid in the total monomers constituting the polylactic acid polymer of the A layer is generally 50 mol% or more, preferably 65 mol% or more. More preferably, it is at least 80 mol%, particularly preferably at least 95 mol% (for example, 100 mol%). Polylactic acid polymers may be used alone or in admixture 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 method for obtaining the polylactic acid polymer is not particularly limited, and known methods such as a condensation polymerization method and 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 number average molecular weight of the polylactic acid polymer is not particularly limited, but is usually 10,000 to 1,000,000, preferably about 30,000 to 400,000, and more preferably about 50,000 to 200,000. If the molecular weight is too small, the mechanical properties as a film, such as tensile elongation at break, tear strength, and impact strength, and long-term physical properties such as weather resistance and heat resistance are inferior. If the molecular weight is too large, molding processability decreases.

  The content of the polylactic acid polymer in the layer A of the present invention is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, and still more preferably, from the viewpoint of controlling the heat shrinkage rate within the range of the present invention. Is 70 to 100%.

  Resin other than the said polylactic acid-type polymer may be contained in A layer of this invention. The resin other than the polylactic acid polymer contained in the A layer is not particularly limited. For example, a polyester resin such as an aliphatic polyester resin or an aromatic polyester resin (polyester corresponding to the above polylactic acid polymer). And polystyrene resins are preferred. Among them, in the case where the shrink film used in the present invention is a single layer film composed of only the A layer, from the viewpoint of adjusting the heat shrinkage characteristics during shrink processing, a polystyrene-based resin, an aliphatic polyester-based resin, an aromatic polyester-based film Resins are preferable, and from the viewpoint of compressive strength, polystyrene resins and aromatic polyester resins are particularly preferable. On the other hand, when the shrink film used in the present invention is a laminated film having a B layer, an aliphatic polyester resin is preferable from the viewpoint of transparency.

  The aliphatic polyester-based resin is a polycondensation of an aliphatic or alicyclic diol component and an aliphatic or alicyclic dicarboxylic acid component, a polycondensation of an aliphatic or alicyclic hydroxycarboxylic acid, or a ring-opening polymerization of lactones. Or a combination thereof. Each monomer component can be used in combination. Examples of the aliphatic or alicyclic diol component include ethylene glycol, 1,3-propanediol, propylene glycol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,6- Examples include aliphatic diols such as hexanediol; polyalkylene glycols such as diethylene glycol; alicyclic diols such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol. Examples of the aliphatic or alicyclic dicarboxylic acid component include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; And alicyclic dicarboxylic acids such as hydronaphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid. As the aliphatic or alicyclic hydroxycarboxylic acid and lactone, those exemplified above can be used.

  In the above aliphatic polyester resin, a part of the aliphatic or alicyclic dicarboxylic acid component (for example, about 0.1 to 50 mol%, preferably 0.1 to 20 mol%) is an aromatic dicarboxylic acid component. It may be replaced. The film obtained by adding the polyester (aromatic aliphatic polyester) thus obtained to the polylactic acid polymer is particularly excellent in impact resistance and has a characteristic that it is not easily broken even after being thermally contracted. Examples of the aromatic dicarboxylic acid include isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. These can be used alone or in admixture of two or more.

  Representative examples of the aliphatic polyester resin include polybutylene succinate (PBS), polyethylene succinate (PES), polybutylene succinate adipate (PBSA), polycaprolactone (PCL), polyhydroxybutyric acid, polyethylene terephthalate succinate. Nate (PETS). Among these, PBS, PCL, and a mixture thereof are preferably used.

  Moreover, the said polystyrene-type resin and aromatic polyester-type resin can be selected and used from the polystyrene-type resin and aromatic polyester-type resin which are illustrated as resin which can be used for B layer.

  When the A layer contains a resin other than a polylactic acid polymer such as an aliphatic polyester resin, an aromatic polyester resin, or a polystyrene resin, the content in the A layer is preferably 10 to 50% by weight, more preferably. Is 20-40% by weight. When the content of the aliphatic polyester resin exceeds 50% by weight, the film becomes too soft and the heat shrink finish is liable to deteriorate, the surface becomes sticky and the handling property is inferior, and the transparency is liable to be lowered.

  In addition to the above, the A layer of the present invention may contain a small amount of other resin components such as biodegradable resins such as aliphatic polyesteramide, aliphatic polyester ether, and aliphatic polyester carbonate. These resins can be used alone or in combination of two or more.

  When the recovered raw material is reused and used in the A layer, the content of the recovered raw material is 30% by weight or less based on the total weight of the A layer from the viewpoint of the tensile elongation characteristics and transparency of the film. Preferably, it is 10 to 30% by weight. In addition, when the shrink film used for this invention is a laminated | multilayer film, since the resin used for B layer is also contained in A layer by adding a collection | recovery raw material, the interlayer adhesive strength of A layer and B layer Is preferable.

  The glass transition temperature (Tg) of the A layer resin of the present invention (a mixture of all resins contained in the A layer) is preferably 40 to 80 ° C, more preferably 50 to 80 ° C, from the viewpoint of processability. When Tg is less than 40 ° C., the natural heat shrinkage of the stretched film is large, and when it exceeds 80 ° C., it is difficult to ensure a sufficient stretch ratio when stretching the film, and the productivity of the film decreases.

  The layer A of the present invention may contain other additives such as a lubricant, a filler, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a colorant and the like as necessary. Good.

  In the case where the shrink film of the present invention is a laminated film of a film layer (B layer) whose main component is a resin other than the A layer and the polylactic acid polymer, the resin used for the B layer is the heat shrinkage rate of the entire shrink film. From the viewpoint of slowly controlling the thickness, it is preferable that the heat shrinkage rate is slower than that of the A layer after the stretching orientation.

  Examples of the resin used as the main component of the B layer include polystyrene resin, polyester resin, polyolefin resin, polyvinyl chloride resin, polyamide resin, polyimide resin, polyphenylene sulfide resin, and acrylic resin. . Among these, polystyrene resins, polyester resins (aromatic polyester resins, aliphatic polyester resins) and polyolefin resins are preferable, and polystyrene resins or aromatic polyester resins are particularly preferable.

  For example, styrene, α-methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, p-isobutyl styrene, pt- The resin is not particularly limited as long as it contains one or more styrene monomers such as butyl styrene and chloromethyl styrene and exhibits heat shrinkability when formed into a film.

  Examples of such polystyrene resins include general polystyrene (GPPS), which is a homopolymer of styrene, a homopolymer or copolymer of styrene monomers; a mixture of polystyrene and synthetic rubber (for example, polybutadiene or polyisoprene), High impact polystyrene (HIPS) with styrene grafted on synthetic rubber; styrene monomer and conjugated dienes such as butadiene and isoprene, such as styrene-butadiene-styrene (SBS) block copolymer Styrene-conjugated diene copolymer that is a polymer (particularly a block copolymer); Styrene-polymerizable unsaturated carboxylic acid that is a copolymer of a styrene monomer and a (meth) acrylate monomer Acid ester copolymer; styrene-conjugated diene-polymerizable unsaturated carboxylic acid ester copolymer; A rubbery elastic material is dispersed in a continuous phase of a copolymer of a monomer and a (meth) acrylic acid ester monomer, and the copolymer is graft-polymerized on the rubbery elastic material. -High impact polystyrene (graft TIPS) etc. are mentioned.

  Examples of the conjugated diene used in the styrene-conjugated diene copolymer include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, and the like. , 3-pentadiene, 1,3-hexadiene, chloroprene and the like. Among these, a styrene-butadiene copolymer using 1,3-butadiene as a conjugated diene is particularly preferable. The form of copolymerization is not particularly limited, but a block copolymer is preferable, and styrene block (S) -conjugated diene block (D) type, SDS type, DSD type, S type. -DSD type etc. are mentioned. In the styrene-conjugated diene copolymer, the styrene content is preferably about 55 to 95% by weight (conjugated diene content: 5 to 45% by weight).

  As the styrene-butadiene copolymer, a styrene-butadiene-styrene (SBS) block copolymer is preferable. In the styrene-butadiene block copolymer, the styrene content is preferably 65 to 90% by weight (butadiene content: 10 to 35% by weight), more preferably 75 to 88% by weight (butadiene content: 12 to 25% by weight). %). The melt flow rate (MFR) (JIS K 7210: temperature 200 ° C./load 49 N) of the styrene-butadiene block copolymer is preferably 1 to 20 g / 10 minutes, more preferably 3 to 10 g / 10 minutes. . As the styrene-butadiene block copolymer, “Asaflex” manufactured by Asahi Kasei Chemicals Corporation, “K-resin” manufactured by Philips Co., Ltd., and the like are available on the market.

Examples of the polymerizable unsaturated carboxylic acid ester used in the styrene-polymerizable unsaturated carboxylic acid ester copolymer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, ( (Meth) acrylic acid alkyl esters (especially (meth) acrylic acid C _1-10 alkyl esters) such as isobutyl acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate; dimethyl fumarate, Examples thereof include fumaric acid mono- or diesters such as diethyl fumarate; maleic mono- or diesters such as dimethyl maleate and diethyl maleate; itaconic mono- or diesters such as dimethyl itaconate and diethyl itaconate. Among these, methyl acrylate and methyl methacrylate are preferably used because of excellent transparency. In addition, (meth) acrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms (for example, about 4 to 10 carbon atoms) such as butyl acrylate or butyl methacrylate is stored at a natural heat shrinkage (25 to 35 ° C.). Is preferable because it contributes to a reduction in the shrinkage rate. These polymerizable unsaturated carboxylic acid esters can be used alone or in admixture of two or more. The styrene content in the styrene-polymerizable unsaturated carboxylic acid ester copolymer is preferably 50 to 98% by weight. More preferably, it is 60-95 weight%, More preferably, it is 70-90 weight%. Here, “(meth) acrylic acid” refers to “acrylic acid and / or methacrylic acid”.

  Examples of the conjugated diene and polymerizable unsaturated carboxylic acid ester copolymer used in the styrene-conjugated diene-polymerizable unsaturated carboxylic acid ester copolymer include the compounds described above. In the styrene-conjugated diene-polymerizable unsaturated carboxylic acid ester copolymer, the styrene content is 50 to 98% by weight, the conjugated diene content is 1 to 45% by weight, and the polymerizable unsaturated carboxylic acid ester copolymer is contained. The amount is preferably 1 to 45% by weight. More preferably, the styrene content is 60 to 90% by weight, the conjugated diene content is 5 to 35% by weight, the polymerizable unsaturated carboxylic acid ester copolymer content is 5 to 35% by weight, and still more preferably the styrene content. Is 65 to 80% by weight, conjugated diene content is 5 to 25% by weight, and polymerizable unsaturated carboxylic acid ester copolymer content is 5 to 25% by weight.

  Among the above, the polystyrene resin used for the B layer of the present invention is particularly preferably a styrene-butadiene block copolymer such as SBS or a styrene-butadiene-isoprene copolymer (SBIS).

  The polyester resin used in the B layer of the present invention is a polyester resin excluding the polylactic acid polymer. Although it may be an aliphatic polyester-based resin as described above or an aromatic polyester-based resin, it is preferably an aromatic polyester-based resin.

  The aromatic polyester-based resin used in the B layer of the present invention is a polyester containing an aromatic ring as a structural unit. Mainly, the aromatic polyester-based resin is a polymer obtained by a condensation reaction of a dicarboxylic acid containing an aromatic dicarboxylic acid and a diol, A polymer or a mixture thereof may be mentioned. In particular, polyesters in which the component exceeding 50 mol% of the dicarboxylic acid component is an aromatic dicarboxylic acid can be mentioned.

  Examples of the aromatic dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 5-t-butylisophthalic acid, 4,4′-biphenyldicarboxylic acid, 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-naphthalenedicarboxylic acid, 2 , 6-Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,2,6,6-tetramethylbiphenyl-4,4′-dicarboxylic acid, 1,1,3-trimethyl-3-phenylindene-4, 5-dicarboxylic acid, 1,2-diphenoxyethane-4,4′-dicarboxylic acid, diphenyl ether dicarboxylic acid, 2 5-anthracene dicarboxylic acid, 2,5-pyridinedicarboxylic acid and substituted products thereof. Among these, terephthalic acid, isophthalic acid, and 2,7-naphthalenedicarboxylic acid are preferable from the viewpoint of productivity, processability, cost, and the like, and terephthalic acid is particularly preferable. In addition to these aromatic dicarboxylic acids, for example, aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, and 1,4 -An alicyclic dicarboxylic acid such as decahydronaphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid or the like may be copolymerized. By copolymerizing these, it is considered that the degree of crystallinity decreases and the slip of the molecular structure is likely to occur, but the shrink characteristics are improved. In addition, the said dicarboxylic acid can be used individually or in mixture of 2 or more types, respectively. From the viewpoint of heat resistance and heat shrinkage properties, the content of the aromatic dicarboxylic acid component in the total dicarboxylic acid component used in the aromatic polyester resin is preferably 60 mol% or more, more preferably 70 mol% or more, More preferably, it is 80 mol% or more.

  Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,3-butanediol, 1, 4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 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, etc. Aliphatic diols, polyalkylene glycols such as diethylene glycol and triethylene glycol, 1,2-cyclohexanedi Alicyclic diols such as butanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 2,2-bis (4 ′ Examples thereof include ethylene oxide adducts of bisphenol compounds such as -β-hydroxyethoxydiphenyl) propane and bis (4'-β-hydroxyethoxyphenyl) sulfone, and aromatic diols such as xylylene glycol. Of these, ethylene glycol, 1,4-cyclohexanedimethanol, and 1,2-cyclohexanedimethanol are preferable. In addition, these can be used individually or in mixture of 2 or more types.

  In addition to the above, the aromatic polyester resin of the present invention includes oxycarboxylic acids such as p-oxybenzoic acid and p-oxyethoxybenzoic acid; monocarboxylic acids such as benzoic acid and benzoylbenzoic acid; Polyhydric carboxylic acids such as acids; monohydric alcohols such as polyalkylene glycol monomethyl ether; polyhydric alcohols such as glycerin, pentaerythritol, and trimethylolpropane are copolymerized within a range that does not impair the effects of the present invention. Also good.

  The specific aromatic polyester resin used in the B layer of the present invention is not particularly limited, but terephthalic acid is the main component as the dicarboxylic acid component, and isophthalic acid, adipic acid, and succinic acid are used as additional components. As the diol component, ethylene glycol or butanediol can be used as a main component. For example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), CHDM copolymerized PET using 1,4-cyclohexanedimethanol (CHDM) as a copolymer component, and diethylene glycol (DEG) and neopentyl glycol as other diol components What added (NPG) is especially preferable from a viewpoint of the heat shrink behavior at the time of setting it as a shrink film, cost, productivity, and an interlayer strength improvement with A layer. The proportion of CHDM copolymerization is preferably 10 to 40 mol%, more preferably 15 to 20 mol%, relative to ethylene glycol. By copolymerizing CHDM at the above ratio, the polyester resin becomes amorphous, which is preferable because adhesion between layers is increased.

  As the aromatic polyester-based resin, existing products can be used. For example, “Easter Polymer” manufactured by Eastman Chemical, “EMBRACE” (above, CHDM copolymerized PET); manufactured by Bell Polyester Products Co., Ltd. “Belpet” (NPG copolymerized PET) and the like are commercially available.

  Moreover, when using an aliphatic polyester-type resin for B layer, it is illustrated as resin which can be used for A layer above-mentioned, such as polybutylene succinate (PBS) and polybutylene succinate adipate (PBSA). It can be selected from aliphatic polyester resins.

  Although it does not specifically limit as polyolefin-type resin used for B layer of this invention, For example, homopolymers, such as polyethylene (PE), polypropylene (PP), polybutylene, polymethylpentene (PMP); Ethylene-alpha-olefin Random copolymers, random copolymers such as propylene-α-olefin random copolymers; copolymers of cyclic olefins and α-olefins (ethylene, propylene, etc.) or graft-modified products thereof, ring-opening weight of cyclic olefins Examples thereof include amorphous cyclic olefin polymers such as coalesced or hydrogenated products thereof or graft-modified products thereof. Among these, polyethylenes such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene catalyst system LLDPE (mLLDPE), and propylene random copolymers such as polypropylene and propylene-α-olefin copolymers. Is preferred. Moreover, these polyolefin resin can be used individually or in mixture of 2 or more types.

  The content of the resin used as the main component of the B layer of the present invention in the B layer varies depending on the type of the resin and is not particularly limited, but is preferably 40 to 100% by weight, more preferably based on the total weight of the B layer. Is 50 to 100% by weight, more preferably 60 to 100% by weight. If it is less than 40% by weight, the effect of improving the shrinkage characteristics of the shrink label may not be obtained, and the characteristics required for the shrink label such as transparency, dimensional stability, and waist strength may be deteriorated. Among these, in the case of a polystyrene resin, the content in the B layer is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, and still more preferably 70 to 100% by weight. In the case of an aromatic polyester resin, it is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, and still more preferably 70 to 100% by weight. In the case of polyolefin resin, it is preferably 70 to 100% by weight, more preferably 80 to 100% by weight, and still more preferably 90 to 100% by weight.

  When the B layer resin of the present invention (a mixture of all resins contained in the B layer) is a polyester resin or a polystyrene resin, the glass transition temperature (Tg) of the B layer resin is 40 to 80 from the viewpoint of workability. ° C is preferred, more preferably 50-70 ° C. When Tg is out of the above range, it may be difficult to sufficiently orient each film layer in the case of lamination or the productivity may be lowered.

  The B layer of the present invention contains other additives such as a lubricant, a filler, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a colorant and the like as necessary. Also good.

  The shrink label of the present invention has at least one printed layer. The printed layer is preferably provided on one surface of the shrink film. Especially, when a shrink film is a laminated | multilayer film, it is preferable to provide in the B layer surface from a viewpoint of improving the followable | trackability and solvent resistance of a printing layer at the time of shrink processing. The printed layer is not particularly limited. However, in the case of a transparent label or the like, if it is applied to the inner side (that is, the adherend side) when attached to a container or the like, the printed layer is peeled off when it is distributed in the market. It is preferable because there is no dirt or dirt. Moreover, when a shrink film is opaque, it is preferable to provide in the outer side (namely, the opposite side to a to-be-adhered body side) from a decorative viewpoint. Furthermore, it may be provided on both surfaces of the shrink film.

  The printing layer of the present invention is a layer displaying a product name, an illustration, handling precautions, and the like, and can be formed by a conventional printing method such as gravure printing or flexographic printing. The printing ink used for forming the printing layer is made of, for example, a pigment, a binder resin, a solvent, and other additives. Although it does not specifically limit as said binder resin, For example, resin, such as an acrylic type, a urethane type, a polyamide type, a vinyl chloride-vinyl acetate copolymer type, a cellulose type, a nitrocellulose type, can be used individually or in combination. As the pigment, white pigments such as titanium oxide (titanium dioxide), indigo pigments such as copper phthalocyanine blue, carbon black, aluminum flakes, mica (mica), and other colored pigments can be selected and used in accordance with the application. In addition, extender pigments such as alumina, calcium carbonate, barium sulfate, silica, and acrylic beads can also be used as pigments for the purpose of adjusting gloss. Examples of the solvent include organic solvents such as methyl ethyl ketone, ethyl acetate, methyl alcohol, ethyl alcohol, and isopropyl alcohol, gravure such as water, and flexographic printing ink, and the compatibility and dispersion of each component in the coating agent. Those usually used for the purpose of improving the properties can be used.

  The printing layer of the present invention varies depending on the type and use of the A layer and B layer, and is not particularly limited, but may be an active energy ray-curable resin layer such as visible light, ultraviolet light, or electron beam. In the case of an active energy ray-curable printing layer, in addition to the above, a photopolymerization initiator such as a photo radical polymerization initiator and a photo cationic polymerization initiator, a sensitizer, etc. should be added to the printing ink. Is preferred.

  The shrink label of the present invention can be provided with, for example, a coating layer, a resin layer, an anchor coat layer, a primer coat layer, an adhesive layer, an adhesive resin layer, etc. in addition to the film layer and the print layer, and a nonwoven fabric. A layer such as paper or a metal thin film may be provided as necessary.

  Although the thickness of the shrink film of this invention changes with uses and is not specifically limited, 10-100 micrometers is preferable, More preferably, it is 20-80 micrometers, More preferably, it is 30-60 micrometers.

  When the shrink film of the present invention is a laminated film, the thickness of the A layer is preferably 5 to 60 μm, more preferably 15 to 40 μm. The thickness of the B layer is preferably 4 to 40 μm, more preferably 10 to 20 μm. The thickness ratio (A layer / B layer) of B layer (sum of all B layer thicknesses in the film) to A layer (sum of all A layer thicknesses in the film) is 80/20 to 20/80. Is preferable, more preferably 80/20 to 30/70, still more preferably 80/20 to 40/60, and most preferably 80/20 to 50/50. With respect to the above range, when the A layer is thick, the heat shrinkage rate is high and the workability may be reduced, or the heat shrinkage stress may be small and the followability of the print layer may be inferior. In contrast, when the B layer is thicker than the above range, the production conditions move to a side where productivity is relatively lowered due to a decrease in heat shrinkage rate or an increase in processing temperature. In addition, the load on the environment is relatively large. Among these, as a particularly preferable thickness configuration, the thickness ratio is 5/90/5 to 1/1/1 (in the case of A / B / A) in a stacked configuration of B / A / B or A / B / A, 1/8/1 to 1/1/1 (more preferably 1/8/1 to 1/2/1) (in the case of B / A / B).

  Although the thickness of the printing layer of this invention is not specifically limited, For example, it is about 0.1-10 micrometers. If the thickness is less than 0.1 μm, it may be difficult to provide a uniform printing layer, and partial “blur” may occur, resulting in a loss of decorativeness or printing as designed. May be difficult. In addition, when the thickness exceeds 10 μm, a large amount of printing ink is consumed, which increases the cost, makes it difficult to apply uniformly, makes the printed layer brittle and easily peels off. . Moreover, the rigidity of a printing layer becomes high and it may become difficult to follow the thermal contraction of a film at the time of shrink processing.

  The shrink label (and shrink film) of the present invention needs to have a specific heat shrinkage rate or heat shrinkage rate immediately after the start of heat shrinkage in warm water at a predetermined temperature. In the present invention, the shrinkage rate of a sample (shrink label or shrink film) under heating conditions measured based on the following measurement principle is defined as a heat shrinkage rate.

  The measurement principle diagram of the heat shrinkage rate is shown in FIG. The heat shrinkage rate is a change in the distance between specific marked lines A and B (distance between marked lines) AB when the strip-shaped sample 1 collected from the shrink label (or shrink film) is placed in a predetermined hot water. Measure by detecting. In the present invention, the distance AB between the marked lines is calculated by measuring an angle θ (also referred to as an opening angle) formed by line segments OA and OB connecting the specific fulcrum O and each of A and B. That is, the heat shrinkage rate of the sample 1 is calculated from the change amount of the angle θ, and the heat shrinkage rate is calculated from the angular velocity. The measuring apparatus, measurement conditions, calculation method, etc. will be described in the section of [Measurement method and evaluation method of heat shrinkage rate, heat shrinkage rate] described later.

  The shrink label of the present invention has a heat shrinkage rate of 3 to 23% in the main orientation direction 1 second after the start of heat shrinkage in 75 ° C. warm water, or the maximum heat in the main orientation direction in 75 ° C. warm water. It is necessary that the shrinkage rate is 7 to 40% / second.

  The shrinkage rate of the shrink label of the present invention in the main orientation direction after 1 second of heat shrinkage in 75 ° C. warm water is 3 to 23%, preferably 3 to 21%, more preferably 4 to 21%, Preferably it is 5 to 19%. If the thermal shrinkage rate exceeds 23%, the thermal shrinkage rate when shrinking the shrink label is too fast, making it difficult to control, causing “wrinkles” or uneven thermal shrinkage. Designability may deteriorate. Also, if the heat shrinkage rate is less than 3%, the heat shrinkage rate is slow and the productivity must be reduced, or heat shrink processing must be performed at a high temperature, so it is used for containers with low heat resistance and contents that are susceptible to heat deterioration. Sometimes it can't be done.

  The maximum heat shrinkage rate in the main orientation direction of the shrink label of the present invention in 75 ° C. warm water is 7 to 40% / second, more preferably 10 to 38% / second, and further preferably 12 to 35% / second. is there. Generally, the heat shrinkage rate at the start of heat shrinkage or immediately after the start of heat shrinkage is the maximum heat shrinkage rate. When the heat shrinkage rate exceeds 40% / second, the heat shrinkage rate when shrinking the shrink label is too high, and it becomes difficult to control, “wrinkles” occur, or heat shrinkage is uneven. As a result, the designability is lowered. Further, when the heat shrinkage rate is less than 7% / second, the heat shrinkage rate is slow, the productivity needs to be lowered, or heat shrinkage processing needs to be performed at a higher temperature. In some cases, the container cannot be used.

  The “main orientation direction” means a direction mainly subjected to stretching treatment. In the case of a uniaxially stretched film, it is the stretching direction (usually the longitudinal direction or the width direction), and in the case of a biaxially stretched film, the direction of large orientation among the two stretching directions (usually the longitudinal direction and the width direction). (In the direction of large heat shrinkage). If the main orientation direction cannot be determined from the manufacturing conditions, for example, the direction with the largest thermal shrinkage (90 ° C., 10 seconds, etc.) in the film is taken as the main orientation direction.

  The heat shrinkage rate in the main orientation direction after 3 seconds after the start of heat shrinkage in 75 ° C. warm water of the shrink label of the present invention is not particularly limited as long as the heat shrinkage rate after 1 second is in the above range, for example, The lower limit is preferably 10%, more preferably 13%, still more preferably 14%, and most preferably 17%. On the other hand, the upper limit is preferably 45%, more preferably 30%, still more preferably 28%, and most preferably 25%.

  The thermal shrinkage rate in the main alignment direction after 10 seconds in 90 ° C. warm water of the shrink label used in the present invention is 40 to 84%, preferably 50 to 80%, more preferably 55 to 75%. . The heat shrinkage rate is a heat shrinkage rate measured after 10 seconds of immersion in a 90 ° C. hot water condition. The heat shrinkage rate is a value related to the draw ratio in the film drawing process and other drawing conditions, and at the same time is a value related to the limit heat shrinkage rate of the shrink label. When the thermal shrinkage rate exceeds 84%, the stretching ratio exceeds 6 times, and not only is the stretching process difficult, but also the elongation at break and impact strength of the film after stretching may be reduced. On the other hand, when the heat shrinkage rate is less than 40%, the amount of heat shrinkage at the time of shrink processing is insufficient, and the finish performance is inferior because the container shape does not sufficiently follow.

  The thermal shrinkage characteristics of the shrink label (heat shrinkage rate at 75 ° C. for 1 second, heat shrinkage rate at 75 ° C. for 3 seconds, heat shrinkage rate at 90 ° C. for 10 seconds, heat shrinkage rate) are as follows. Therefore, it is preferable that each shrinkage rate of the shrink film is in the same range as the shrink label. These heat shrink characteristics can be controlled by the content of the polylactic acid polymer, the type and content of the resin other than polylactic acid, the thickness and thickness ratio of the film layer, the stretching orientation condition of the shrink film, and the like.

  The feature of the present invention is that shrink processing is performed by using a composite (lamination, mixing, etc.) of a polylactic acid polymer having a high heat shrinkage rate and a polystyrene resin or an aromatic polyester resin having a slow heat shrinkage rate. This is because the heat shrinkage rate is controlled so that high productivity, workability, and beautiful finish can be achieved at the same time. In the present invention, even if the shrink film is a single-layer film made of a composition of a polylactic acid polymer and another polymer, the A layer containing the polylactic acid polymer as a main component, Even in the case of a multilayer film composed of a combination with other layers such as a B layer mainly composed of a polymer, the polylactic acid-based polymer plays a role as a component for increasing the heat shrinkage rate of the film. These polymers have the role of reducing the heat shrinkage rate. In a film having a polylactic acid polymer as the main component of the A layer as a single component, the heat shrinkage rate is fast and the heat shrinkage behavior is abrupt. As a result, the shrinkage behavior during shrink processing can be controlled. It becomes difficult to easily cause problems such as “wrinkles” and “distortion of the printing layer”. On the other hand, in a film having the main component (for example, polystyrene resin) of the B layer as a single component, the heat shrinkage rate is slow and the environment is inferior. By combining an environmentally superior plant-derived polylactic acid polymer with, for example, a polystyrene polymer or a polyester polymer as a composition or a laminate, an environmentally superior label can be obtained and obtained. By adjusting the heat shrinkage rate of the film, the heat shrinkage behavior during shrink processing can be easily controlled, and by adjusting the composition ratio and layer structure of both, the production efficiency of the shrink processing and the product The finish can be improved.

  These combinations are effective not only in adjusting the heat shrinkage rate but also in adjusting the heat shrinkage stress. That is, since the polylactic acid-based polymer has a small heat shrinkage stress, when used alone, when the printing layer is thick, such as when the printing layer is thick or when containing a large amount of inorganic pigment, the printing layer does not shrink when shrinking. The film may not follow the heat shrinkage of the film well, and the finish may be reduced. On the other hand, when the resin used for the B layer is an aromatic polyester-based resin or a polystyrene-based resin, the heat shrinkage stress of the shrink label is improved because the heat shrinkage stress relative to the A layer is large. Furthermore, since the B-layer polystyrene-based resin and aromatic polyester-based resin have better sealing properties than the polylactic acid-based polymer (center seal suitability with a solvent described later), the B layer is used as a surface layer. Is preferable because of good sealing properties. In addition, since the heat shrinkage characteristics are greatly different between the A layer and the B layer as described above, it is preferable to adopt a B / A / B type 2 type 3 layer laminated structure from the viewpoint of preventing problems such as curling.

  The thermal shrinkage rate (warm water, 90 ° C., 10 seconds) in the direction orthogonal to the main orientation direction of the shrink label and the shrink film of the present invention is preferably −3 to 15%, more preferably from the viewpoint of shrink workability. -1 to 10%.

  The transparency (haze value: JIS K 7136) (unit:%) of the shrink film of the present invention is preferably 10 or less, more preferably 5 or less. When the haze value exceeds 10, the inside of the shrink film (the side that becomes the container side when the label is attached to the container) is printed, and in the case of a shrink label that shows printing through the film, , Printing may become cloudy and decorative properties may be reduced.

  Blocking resistance of the shrink film used in the present invention (B layer surface in the case of a laminated film) (peel strength in a T-type peel test according to JIS K 6854-3, pressure condition: 40 ° C., 0.3 MPa, 180 seconds) is preferably 0.1 N / 15 mm or less. When the peel strength exceeds 0.1 N / 15 mm, blocking is likely to occur, and productivity and workability may be reduced, or handling failure may occur when the shrink label of the present invention is used in a heated state. .

  The heat shrinkage stress (85 ° C.) in the main orientation direction of the shrink film of the present invention is preferably 3 to 11 MPa, more preferably 4 to 8 MPa. When the heat shrinkage stress is less than 3 MPa, the shrinkage followability of the printed layer is lowered, and the finish may be lowered. If it exceeds 11 MPa, the container may be deformed or the contents may overflow when opened.

  The shrink label of the present invention is, for example, a cylindrical shrink label of a type in which both ends of the label are sealed with a solvent or an adhesive and attached to the container, and one end of the label is attached to the container, and the label is wound Then, it can be suitably used as a wrapping type shrink label in which the other end is overlapped with one end to form a cylinder. The center seal strength of this cylindrical shrink label is preferably 2.0 (N / 15 mm) or more. When the seal strength is less than 2.0 (N / 15 mm), the seal part is peeled off after the processing step or commercialization, and the productivity is lowered or the label is dropped. Moreover, it is preferable that the seal part of the cylindrical shrink label is not whitened.

  One aspect of achieving the above-described shrink label having heat shrinkage characteristics is at least a film layer (A layer) containing a polylactic acid polymer as an essential component and a film layer (B1 layer) containing a polystyrene resin as a main component. A laminated shrink film having one layer at a time, the thickness ratio (A layer thickness / B1 layer) of A layer (sum of all A layer thicknesses in the film) and B1 layer (sum of all B1 layer thicknesses in the film) A shrink film and a printed layer having a thickness) of 80/20 to 20/80, preferably 80/20 to 30/70, more preferably 80/20 to 40/60, and most preferably 80/20 to 50/50. It is a shrink label.

  As the polystyrene resin used for the B1 layer, the above-mentioned polystyrene resin can be used. The content of the polylactic acid polymer in the A layer is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, and still more preferably 70 to 100% by weight. The content of the polystyrene resin in the B1 layer is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, and still more preferably 70 to 100% by weight. Moreover, in the A layer, the above-mentioned aliphatic polyester resin may be contained in an amount of 1 to 50% by weight, more preferably 2 to 40% by weight, and still more preferably about 5 to 30% by weight.

  Another embodiment for achieving a shrink label having the above heat shrink property is a film layer (A layer) containing a polylactic acid polymer as an essential component, and a film layer (B2) containing an aromatic polyester resin as a main component. Layer) is a laminated shrink film having at least one layer, and a thickness ratio (A layer) of A layer (total thickness of all A layers in the film) and B2 layer (total thickness of all B2 layers in the film) (Thickness / B2 layer thickness) is 80/20 to 20/80, preferably 80/20 to 30/70, more preferably 80/20 to 40/60, most preferably 80/20 to 50/50. And a shrink label having a printed layer.

  As the aromatic polyester resin used for the B2 layer, the above-described aromatic polyester resin can be used. The content of the polylactic acid polymer in the A layer is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, and still more preferably 70 to 100% by weight. The content of the aromatic polyester resin in the B2 layer is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, and still more preferably 70 to 100% by weight. Moreover, in the A layer, the above-mentioned aliphatic polyester resin may be contained in an amount of 1 to 50% by weight, more preferably 2 to 40% by weight, and still more preferably about 5 to 30% by weight.

  The shrink label of the present invention is attached to a container and used as a labeled container. Such containers include, for example, soft drink bottles such as PET bottles, milk bottles for home delivery, food containers such as seasonings, alcoholic beverage bottles, pharmaceutical containers, containers for chemical products such as detergents and sprays, cups, etc. This includes noodle containers. The shape of the container includes various shapes such as a cylindrical shape, a square bottle, and a cup type. Further, the material of the container includes plastic such as PET, glass, metal and the like.

  Below, an example of the manufacturing method of the shrink label of this invention, and the mounting method with respect to a container is demonstrated. Here, a B / A / B type 2 type 3 layer shrink label having an A layer made of a polylactic acid polymer and a B layer made of a polystyrene resin will be described as an example, but the present invention is not limited to this. In the following description, in the order of the process, the original film after stretching is “shrink film”, the one subjected to printing treatment is “long shrink label”, and further processed into a cylindrical shape with a long length. It is described as “long cylindrical shrink label”.

[Shrink film]
The polylactic acid polymer and polystyrene resin used for the shrink film of the present invention can be polymerized using a known technique. Moreover, these resin can use a commercially available thing. For example, as the polylactic acid polymer, “Lacia” manufactured by Mitsui Chemicals, Inc., “Nature Works” manufactured by Nature Works, etc. may be used. As the styrene resin, for example, “Afusalex” manufactured by Asahi Kasei Co., Ltd., “K-resin” manufactured by Phillips, “SC004” manufactured by PS Japan Co., Ltd., or the like can be used as the styrene-butadiene copolymer. Is possible. Moreover, it is also possible to add a certain amount of recovered raw materials as necessary from the viewpoint of cost and recycling.

  Next, a laminated film is prepared using the obtained raw material. As a lamination method, a conventional method, for example, a T-die type or inflation type co-extrusion method, a dry lamination method, a sand lamination method, or the like can be used. Moreover, after extending | stretching, you may extend | stretch and it is also possible to laminate | stack the stretched films. Among these, from the viewpoint of productivity, a method of stretching after producing a laminated unstretched film by a coextrusion method is preferable. Below, the example of the co-extrusion method (B / A / B type 2 type | mold 3 layer lamination | stacking) is shown.

  The extruder a set at a predetermined temperature is charged with a polylactic acid polymer, the extruder b is charged with a polystyrene resin, co-extruded from a T die, a circular die, etc., and rapidly cooled using a cooling drum or the like. And an unstretched laminated film is created. At this time, it is preferable to use a B / A / B type 2 type 3 layer laminated structure by using a 3 layer manifold or a merge block. Further, if necessary, the supply amount may be adjusted using a gear pump, and it is preferable to remove foreign substances using a filter because film tearing can be reduced. The extrusion temperature varies depending on the type of polylactic acid polymer and polystyrene resin used, and is not particularly limited, but is preferably 190 to 250 ° C. Further, if necessary, other admixtures such as a lubricant, an antistatic agent, an antifogging agent and an antioxidant may be mixed.

  Depending on the application, co-extrusion may be performed using three extruders. In that case, it is possible to provide laminated portions made of different resins and different thicknesses on both sides of the A layer.

  Next, the obtained unstretched laminated film is stretched to produce a long shrink film. The stretching may be biaxial stretching in the longitudinal direction (longitudinal direction; MD direction) and width direction (transverse direction; TD direction), or may be uniaxial stretching in the longitudinal direction or the width direction. The stretching method may be any of a roll method, a tenter method, and a tube method. The stretching treatment is performed at a temperature of about 70 to 110 ° C., if necessary, for example, 1.01 to 1.5 times, preferably about 1.05 to 1.3 times in the longitudinal direction, and then 2 in the width direction. It is carried out by stretching about 8 times, preferably about 3 to 6 times.

  Further, the surface of the shrink film of the present invention may be subjected to a conventional surface treatment such as corona discharge treatment or primer treatment (undercoat treatment) as necessary.

[Shrink label]
Next, a printing layer is formed on at least one surface of the long shrink film obtained as described above, thereby producing a long shrink label. The printing layer is formed by applying a printing ink prepared by mixing a pigment, a binder resin, a solvent, other additives, and the like. The method of application may be in-line coating applied during the shrink film manufacturing process (for example, unstretched or after longitudinal uniaxial stretching) or offline coating applied after film formation, and is not particularly limited. From the viewpoint of productivity, workability, etc., off-line coating is preferred. As a printing method, a conventional method can be used, but gravure printing or flexographic printing is most preferable.

  The label is slit into a predetermined width and wound into a roll shape, and a shrink label (long shrink label) is obtained as a plurality of roll-like objects.

[Processing of long shrink labels]

  Although an example of the process which mounts the obtained shrink label on a container is shown below, a manufacturing method is not limited to this.

  While feeding one of the rolls, the long shrink film is formed into a cylindrical shape so that the width direction is the circumferential direction. Specifically, a long shrink label is formed into a cylindrical shape, and a solvent or adhesive (hereinafter referred to as “THF”) having a width of about 2 to 4 mm in the longitudinal direction on one side edge of the label. Solvent etc.) is applied to the inner surface, rolled up into a cylindrical shape, and the solvent applied portion is overlapped at a position of 5-10 mm from the other side edge and adhered to the outer surface (center seal). A long cylindrical shrink label is obtained.

  In the case where a perforation for label excision is provided, a perforation having a predetermined length and pitch is formed in the longitudinal direction. The perforation can be applied by a conventional method (for example, a method of pressing a disk-shaped blade having a cut portion and a non-cut portion repeatedly formed around it, a method using a laser, or the like). The process stage for perforating can be appropriately selected after the printing process and before and after the cylindrical processing process.

[Container with label]
Finally, after cutting the long cylindrical shrink label obtained above, it is mounted on a predetermined container, and the container is manufactured by heat-shrinking the label to heat shrink and follow the container. The above long cylindrical shrink label is supplied to an automatic label mounting device (shrink labeler), cut to the required length, and then externally fitted into a container filled with contents, and a hot air tunnel or steam tunnel at a predetermined temperature is attached. Passed or heated with radiant heat such as infrared rays to cause heat shrinkage and adhere to the container to obtain a labeled container. Examples of the heat treatment include treatment with steam at 80 to 100 ° C. (passing through a heating tunnel filled with steam and steam).

[Measurement method and evaluation method of heat shrinkage rate and heat shrinkage rate]
Below, based on the measurement principle shown above and shown in FIG. 1, the method (measurement apparatus, measurement method, calculation method) of measuring the heat shrinkage rate and the heat shrinkage rate in the present invention will be described.

(1) Measuring device The measuring device used in the present invention is a rotation angle measurement that measures a rotation angle at the position of a fulcrum O and two arms corresponding to OA and OB in FIG. A vessel is installed. One of the arms (OA) is an arm fixed to the pedestal. The other arm (OB) is a movable arm attached to the rotation shaft of the rotation angle measuring device, and can freely rotate around the fulcrum O (the rotational torque is 2 mN · m or less). It is. Each of the two arms is installed horizontally with the ground.
A fastener (clip) for fixing the sample (film) is attached to the arm tip (corresponding to points A and B). If necessary, a structure in which a sample support arm is vertically attached to the arm tip and a sample fixing bracket is attached to the tip of each sample support arm may be employed. Each fastener is positioned so as to be horizontal to each other.
In addition, the sample part of the said apparatus can be moved to warm water, maintaining a measurement system. For example, the pedestal is mounted on a temperature-controllable water tank, is movable up and down, and has a structure in which the sample portion can be quickly immersed in water temperature-controlled at a predetermined temperature by sliding the pedestal up and down. .

(2) Measuring method Shrink labels to be measured are cut into strips having a length of 100 mm and a width of 5 mm in the main orientation direction (width direction in the case of the shrink labels of Examples and Comparative Examples), and this is referred to as a sample film. did. Mark lines with an interval of 88.0 mm were provided so as to leave the grip allowance substantially equally at both ends of the sample film.
This sample film is fixed to the tip of the arm (or sample support arm). Fix the part of one marked line to the clamp of the fixed arm (OA), then fix the other marked line part to the other clamp while adjusting the opening angle of the movable arm (OB), The distance between both fasteners was adjusted to be exactly 88 mm. The length of OA and OB is 100 mm.
Next, the sample film part is quickly immersed in a water bath adjusted to 75 ° C. ± 0.5 ° C., and at the same time, measurement of the change in the angle θ (opening angle) between the arms OA and OB due to the thermal contraction of the sample film is started. The opening angle was measured every 0.1 second after the start of measurement.
In addition, the measurement conditions used for the measurement of an Example and a comparative example are as follows.
(Measurement, equipment conditions)
Rotation angle measuring device: Non-contact type rotation angle sensor “CP-2UK-R200” manufactured by Midorokki
Arm: Aluminum prism (cross section: 10mm x 10mm)
Hot water temperature: 75 ° C ± 0.5 ° C (when measuring 75 ° C)

(3) Calculation method (3-1) Thermal contraction rate (s _t )
The distance between the marked lines of the sample is calculated from the measured opening angle (distance between marked lines = OA (or OB) × sin (θ / 2) × 2), and the initial distance between marked lines (L ₀ = 88 mm) and t The thermal contraction rate s _t (%) after t seconds is obtained from the distance between the marked lines after second (L _t ) by the following formula 1, and s _t from 0.1 to 0.1 seconds is plotted on the graph.
_{s t = (L 0 -L t} ) × 100 / L 0 ( Equation 1)

(3-2) Thermal contraction rate (V _t ), maximum thermal contraction rate (V _max )
Next, the thermal contraction speed V _t is obtained by Equation 2 for each measurement point.
_{V t = (s t + 0.2} -s t) /0.2 ( Equation 2)
The meaning of the above formula 2, the heat shrinkage rate of t seconds after the start of the measurement of the (t + 0.2) sec thermal shrinkage ratio after (s t _{+ 0.2)} and the t seconds thermal shrinkage ratio after (s _t) The difference is defined as a number obtained by dividing the difference by 0.2 seconds (that is, the slope between two points). The maximum value of V _t obtained for all measurement points at intervals of 0.1 seconds in one sample is defined as the maximum heat shrinkage rate (V _max ).
The measurement is performed at least until the change in the heat shrinkage rate reaches a steady state.

(3-3) Thermal contraction start point (T ₀ )
In the present invention, FIG. 2 shows an example of a graph in which the thermal contraction rate s _t (vertical axis) after t seconds obtained by Equation 1 is plotted against time t (horizontal axis). A curve in the graph is a change in heat shrinkage rate, and a straight line is a straight line (approximate to a tangent line) having the following maximum slope (which is V _max ). The origin (t = 0) is the time when the sample film is immersed in warm water and measurement is started.
Since the film starts thermal contraction with a slight delay from the origin and is affected by the delay in heat conduction at the rising edge of the contraction, the curve is often an S-shaped curve.
Therefore, in the present invention, the thermal contraction start point (T ₀ ) is defined as follows. A straight line with a slope of V _max is drawn through the measurement point where V _max is obtained, and the intersection with the time axis is obtained. The time (sampling time) of the first measurement point after this intersection time is defined as the thermal contraction start point (T ₀ ).

(3-4) Thermal contraction rate at ₁ and 3 seconds after start of thermal contraction (S ₁ , S ₃ )
As shown in FIG. 2, the heat shrinkage rate S ₁ after 1 second (T ₁ ) from T ₀ was defined as “heat shrinkage rate 1 second after the start of heat shrinkage”. Similarly, the thermal contraction rate S ₃ after 3 seconds from T ₀ (T ₃ ) was defined as “the thermal contraction rate 3 seconds after the start of thermal contraction”.

(4) Thermal shrinkage at 90 ° C. for 10 seconds (S ₁₀ ′)
The temperature of the water tank was changed to 90 ° C. ± 0.5 ° C., the heat shrinkage rate was measured in the same manner as in (3) above, and the heat shrinkage rate after 10 seconds from T ₀ ′ using the same calculation method. S ₁₀ ′ (heat shrinkage rate after 10 seconds from the start of heat shrinkage) was determined and set as “heat shrinkage rate at 90 ° C. for 10 seconds”.

[Other evaluations]
(1) Transparency (haze value) (unit:%)
Measurement is performed according to JIS K 7136. Converted to a thickness of 40 μm, evaluation is made according to the following criteria.
5.0 or less: Excellent transparency for label use (◎).
Greater than 5.0 and 10 or less: Transparency sufficient for label use (◯).
Greater than 10: The transparency is insufficient for label use (×).

(2) Film layer thickness, printing layer thickness The film thickness was measured using a dial gauge. The thickness of the printed layer was measured using a three-dimensional microscope (Keyence Co., Ltd. VK8510) for the level difference between the portion provided with the print layer (application surface) and the portion not provided with the print layer (non-application surface).

(3) Seal strength After the center-sealed cylindrical shrink label is cut in the circumferential direction of the label so as to have a width of 15 mm in the height direction of the label, and a ring-shaped label piece having a width of 15 mm is collected, The ring-shaped label piece is cut at a portion other than a portion where a center seal is applied (hereinafter referred to as a seal portion), and a strip-shaped sample piece having a long side in the circumferential direction is created.
The sample piece is chucked and pulled by a tensile tester so as to be T-type peeled, and a T-type peel test (conforming to JIS K 6854-3) is performed under the following conditions. Note that the initial chuck interval is 40 mm, and measurement is performed with the seal portion set to be the center between the chucks. The test is conducted until the sample piece is broken.
The maximum load obtained in the test is taken as the seal strength (N / 15 mm). If the seal strength is 2 (N / 15 mm) or more, the center seal property is judged as good (◯) and less than 2 (N / 15 mm) In this case, it is determined that the sealing performance is poor (x).
(In the above measurement, if necessary, film pieces that do not stretch may be joined together and used for the measurement.)
Measuring device: Shimadzu Corporation autograph (AGS-50G: load cell type 500N)
Temperature and humidity: Temperature 23 ± 2 ° C, humidity 50 ± 5% RH (JIS K 7000 standard temperature state 2nd grade)
Initial chuck interval: 40 mm
Sample width: 15mm
Number of tests: 3 times Crosshead moving speed: 200 mm / min

(4) Thermal shrinkage stress From the shrink film obtained in the examples and comparative examples, the shrink film main stretching direction (width direction in the examples and comparative examples) is 200 mm, and the direction orthogonal to the main stretching direction (examples and comparative examples). In the longitudinal direction), a substantially rectangular film piece of 15 mm was cut out and used as a sample.
Set to a chuck of a tensile tester ("Autograph AGS-50G" manufactured by Shimadzu Corporation, load cell 500N) with a chuck distance of 100 mm (the main stretch direction of the shrink film is the tensile direction of the tensile tester), and the chuck distance (100 mm) was held for 10 seconds in 85 ° C. warm water. In addition, the part to 80 mm was immersed in warm water among 100 mm between chuck | zippers.
The stress generated at this time was detected, and the maximum value was defined as the heat shrinkage stress.

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. Examples 6 to 8 are referred to as “reference examples”.

Example 1
As the A layer resin, a mixed resin (70% by weight of polylactic acid resin (“Lacia H-280” manufactured by Mitsui Chemicals, Inc.) and 30% by weight of polybutylene succinate (“Bionore 1003” manufactured by Showa Polymer Co., Ltd.) Resin A1) was used. Moreover, 100 weight% (resin B1) of SBS resin (Asahi Kasei Chemicals Corporation "Asaflex 825") was used as B layer resin.
Resin A1 was charged into the extruder a heated to 210 ° C., and the resin B1 was charged into the extruder b heated to 225 ° C. Melt extrusion was performed using the above two extruders. The resin extruded from the extruder a is merged using a merge block so that the resin extruded from the extruder b is a laminated portion on both sides of the substrate layer, and extruded from a T die (slit spacing 1 mm). Then, it rapidly cooled on the casting drum cooled at 25 degreeC, and obtained the 2 type 3 layer lamination | stacking unstretched film of a laminated part (B1) / base layer part (A1) / laminated part (B1). The lamination thickness ratio of the unstretched film was B1 / A1 / B1 = 1/3/1.
Next, the unstretched film is stretched 1.3 times in the length direction using a roll stretching machine, and then thermally contracted mainly in a uniaxial direction by being stretched 5.3 times in the width direction. A biaxially stretched film (shrink film) was obtained. The total thickness of the film was 50 μm (layer thickness ratio: 1/3/1).
Subsequently, acrylic ink (trade name “PS-985”, manufactured by Sakata Inx Co., Ltd.) was applied to one side of the obtained shrink film by gravure printing to form a printing layer (thickness 3 μm), and a shrink label was obtained.
The thermal shrinkage rate (S ₁ ) in the main orientation direction after 1 second (T ₁ ) of heat shrinkage in 75 ° C. warm water of the obtained shrink label was 9%, and after 3 seconds (T ₃ ) of heat shrinkage start The heat shrinkage rate (S ₃ ) in the main orientation direction was 17%, and the heat shrinkage rate (S ₁₀ ′) at 90 ° C. for 10 seconds was 55%. The maximum heat shrinkage rate (V _max ) was 10.1% / second.
The shrink label was rolled into a cylindrical shape so that the printing surface was inside and the width direction of the film was the circumferential direction, and center-sealed with tetrahydrofuran (THF) to obtain a cylindrical shrink label. Furthermore, the cylindrical shrink label was attached to a container (500 ml heat-resistant square PET bottle manufactured by Toyo Seikan Co., Ltd.) and heat-shrinked in a steam tunnel having an atmospheric temperature of 90 ° C. to obtain 96 labeled containers. The obtained labeled container had no defects such as “wrinkles” and was an excellent finish.

Example 2
A shrink film having a total thickness of 50 μm and a shrink label were obtained in the same manner as in Example 1 except that the layer thickness ratio was changed to B1 / A1 / B1 = 1/5/1. The resulting shrink label had a heat shrinkage rate (S ₁ ) of 19%, a heat shrinkage rate (S ₃ ) of 26%, and a heat shrinkage rate (S ₁₀ ′) after 90 seconds at 90 ° C. of 62%. The maximum heat shrinkage rate (V _max ) was 25.8% / second.
Further, 96 labeled containers were obtained in the same manner as in Example 1. The obtained labeled container had no defects such as “wrinkles” and was an excellent finish.

Example 3
A shrink film having a total thickness of 50 μm and a shrink label were obtained in the same manner as in Example 1 except that the layer thickness ratio was changed to B1 / A1 / B1 = 1/8/1.
The resulting shrink label had a heat shrinkage rate (S ₁ ) of 21%, a heat shrinkage rate (S ₃ ) of 27%, and a heat shrinkage rate (S ₁₀ ′) after 90 seconds at 90 ° C. of 65%. The maximum heat shrinkage rate (V _max ) was 39.2% / second.
Further, 96 labeled containers were obtained in the same manner as in Example 1. The obtained labeled container had no defects such as “wrinkles” and was an excellent finish.

Comparative Example 1
Using only one extruder, a single-layer film made of resin A1 was produced.
Resin A1 was put into an extruder heated to 210 ° C., melt-extruded from a T-die (slit spacing 1 mm), and then rapidly cooled on a casting drum cooled to 25 ° C. to obtain a single-layer unstretched film. . Further, in the same manner as in Example 1, a shrink film having a total thickness of 50 μm and a shrink label were obtained.
The obtained shrink label had a heat shrinkage rate (S ₁ ) of 24%, a heat shrinkage rate (S ₃ ) of 30%, and a heat shrinkage rate (S ₁₀ ′) after 10 seconds at 90 ° C. of 70%. The maximum heat shrinkage rate (V _max ) was 115.7% / second.
Further, 96 labeled containers were obtained in the same manner as in Example 1. “Wrinkles” were observed on 17 of the obtained labeled containers, and the appearance was inferior.

Examples 4-8
As a raw material, a mixed raw material of 70 parts by weight of a polylactic acid polymer shown in Table 1 and 30 parts by weight of an additive resin (a resin other than a polylactic acid polymer) is used, and only one extruder is used, and the mixed resin is used. A single layer film was prepared.
A mixed raw material was charged into an extruder heated to 190 ° C., melt-extruded from a T-die (slit interval 1 mm), and then rapidly cooled on a casting drum cooled to 25 ° C. to obtain a single-layer unstretched film. . Furthermore, horizontal uniaxial stretching was performed under the stretching conditions shown in Table 1 to obtain a shrink film having a total thickness of 50 μm. Further, a shrink label was obtained in the same manner as in Example 1.
Table 1 shows the thermal shrinkage rate (S ₁ ), thermal shrinkage rate (S ₃ ), thermal shrinkage rate after 10 seconds at 90 ° C. (S ₁₀ ′), and maximum thermal shrinkage rate (V _max ). That's right.
Further, 96 labeled containers were obtained in the same manner as in Example 1. As shown in Table 1, the obtained labeled container had no defects such as “wrinkles” and had an excellent finish.

Examples 9-15
As the A-layer resin (A-layer raw material) and the B-layer resin (B-layer raw material), a resin shown in Table 2 was used, and a two-type three-layer laminated film was prepared with the composition shown in Table 2.
The layer A resin was charged into the extruder a heated to 190 ° C., and the layer B resin was charged into the extruder b heated to 180 ° C. The resin extruded from the extruder a is merged using a merge block so that the resin extruded from the extruder b is a laminated portion on both sides of the substrate layer, and extruded from a T die (slit spacing 1 mm). Then, it rapidly cooled on the casting drum cooled at 25 degreeC, and the 2 type 3 layer lamination | stacking unstretched film of a laminated part (B layer) / base layer part (A layer) / laminated part (B layer) was obtained. Furthermore, transverse uniaxial stretching was performed under the stretching conditions shown in Table 2 to obtain a shrink film having a total thickness of 50 μm. Further, a shrink label was obtained in the same manner as in Example 1.
Table 2 shows the thermal shrinkage rate (S ₁ ), thermal shrinkage rate (S ₃ ), thermal shrinkage rate after 10 seconds at 90 ° C. (S ₁₀ ′), and maximum thermal shrinkage rate (V _max ) of the obtained shrink label. That's right.
Further, 96 labeled containers were obtained in the same manner as in Example 2. As shown in Table 2, the obtained labeled container had no defects such as “wrinkles” and had an excellent finish.

  The unit of “blending amount” in Table 2 is parts by weight, and details of the raw material resins used in Examples 4 to 15 are shown in Table 3.

It is a principle figure of the measurement of the thermal contraction rate and the maximum thermal contraction rate immediately after the start of thermal contraction of the present invention. Obtained in the heat shrinkage measured present invention, an example of a graph plotting the relationship between thermal shrinkage s _t at time t and time t.

Explanation of symbols

1 Sample film O Support point A, B Mark line θ Angle formed by OA and OB (open angle)

Claims (5)

A shrink label having a printed film and a shrink film having at least one film layer (A layer) comprising a polylactic acid polymer as an essential component,
The shrink film is a laminated shrink film further comprising at least one film layer (B layer) mainly comprising a resin other than a polylactic acid polymer that is a polystyrene resin or an aromatic polyester resin,
The ratio of the film layer thickness of all A layers and the film layer thickness of all B layers (A layer thickness / B layer thickness) of the laminated shrink film is 80/20 to 20/80,
The content of the polylactic acid polymer in the layer A is 50% by weight or more,
The proportion of the D-lactic acid component in the total lactic acid component in the monomer component constituting the polylactic acid polymer is 4 to 15% by weight,
The content of the resin other than the polylactic acid-based polymer in the B layer is 70 to 100% by weight,
The heat shrinkage rate in the main orientation direction at 1 second after the start of heat shrinkage in 75 ° C. warm water is 3 to 23%, and the heat shrinkage rate in the main orientation direction at 90 ° C. and 10 seconds is 40 to 84%. Shrink label. A shrink label having a printed film and a shrink film having at least one film layer (A layer) comprising a polylactic acid polymer as an essential component,
The shrink film is a laminated shrink film further comprising at least one film layer (B layer) mainly comprising a resin other than a polylactic acid polymer that is a polystyrene resin or an aromatic polyester resin,
The ratio of the film layer thickness of all A layers and the film layer thickness of all B layers (A layer thickness / B layer thickness) of the laminated shrink film is 80/20 to 20/80,
The content of the polylactic acid polymer in the layer A is 50% by weight or more,
The proportion of the D-lactic acid component in the total lactic acid component in the monomer component constituting the polylactic acid polymer is 4 to 15% by weight,
The content of the resin other than the polylactic acid-based polymer in the B layer is 70 to 100% by weight,
The maximum heat shrinkage rate in the main alignment direction in 75 ° C. warm water is 7 to 40% / second, and the heat shrinkage rate in the main alignment direction at 90 ° C. for 10 seconds is 40 to 84%. Shrink label.   The shrink label according to claim 1 or 2, wherein the laminated shrink film is a laminated shrink film having the B layer on both sides of the A layer or the A layer on both sides of the B layer. A shrink label having a printed film and a shrink film having at least one film layer (A layer) comprising a polylactic acid polymer as an essential component,
The shrink film is a single layer shrink film of the A layer,
The content of the polylactic acid polymer in the layer A is 50% by weight or more,
The A layer further contains 10 to 50% by weight of a resin other than a polylactic acid polymer selected from the group consisting of a polystyrene resin and an aromatic polyester resin,
In the monomer component constituting the polylactic acid polymer, the proportion of the D-lactic acid component in the total lactic acid component is 5% by weight or less,
The content of the aromatic dicarboxylic acid component in the total dicarboxylic acid component used in the aromatic polyester-based resin is 60 mol% or more,
The heat shrinkage rate in the main orientation direction at 1 second after the start of heat shrinkage in 75 ° C. warm water is 3 to 23%, and the heat shrinkage rate in the main orientation direction at 90 ° C. and 10 seconds is 40 to 84%. Shrink label. A shrink label having a printed film and a shrink film having at least one film layer (A layer) comprising a polylactic acid polymer as an essential component,
The shrink film is a single layer shrink film of the A layer,
The content of the polylactic acid polymer in the layer A is 50% by weight or more,
The A layer further contains 10 to 50% by weight of a resin other than a polylactic acid polymer selected from the group consisting of a polystyrene resin and an aromatic polyester resin,
In the monomer component constituting the polylactic acid polymer, the proportion of the D-lactic acid component in the total lactic acid component is 5% by weight or less,
The content of the aromatic dicarboxylic acid component in the total dicarboxylic acid component used in the aromatic polyester-based resin is 60 mol% or more,
The maximum heat shrinkage rate in the main alignment direction in 75 ° C. warm water is 7 to 40% / second, and the heat shrinkage rate in the main alignment direction at 90 ° C. for 10 seconds is 40 to 84%. Shrink label.

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