JP4849853B2 - Light-shielding shrink tack sheet and label using the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a light-shielding shrink tack sheet for pharmaceuticals used for containers such as pharmaceuticals, and a label produced using the same.

  Conventionally, shrink film is widely used for containers made of glass, synthetic resin, etc. for cosmetics, pharmaceuticals, etc., because it can be packaged in a state of maintaining high adhesion to containers with complicated shapes. It has been. In particular, polyethylene terephthalate-based shrink films with excellent transparency and low-temperature shrinkage have a good finish without wrinkles after shrinkage. Widely used in packaging.

  Furthermore, in addition to the purpose of decorating the recent shrink film, there is also a problem of protecting the contents from ultraviolet light, and a shrink film that has been provided with ultraviolet absorbing performance while maintaining transparency has been proposed ( Patent Documents 1 and 2). Moreover, when packaging a container using a shrink film, the shrink label which described the chemical name, the manufacturer's name, the usage, the expiration date, etc. may be stuck on the trunk | drum surface. A shrink label in which a light shielding layer is provided together with such a printed layer to improve the light shielding property has been proposed (Patent Document 3).

  Patent Document 1 described above discloses a container using a shrink film containing a benzotriazole ultraviolet absorber (trade name: Tinupin 327). Further, in Patent Document 2, a salicylic acid-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ultraviolet absorber is contained in a synthetic resin film, or coated on the surface of the synthetic resin film, so that ultraviolet rays from sunlight can be used. A shrink packaging of a urine test paper storage container that is less affected by the above is disclosed.

In Patent Document 3, a light shielding layer is formed of a coating layer of a coating liquid containing titanium oxide powder as a light shielding material, and the transmittance in visible light (400 to 700 nm) is adjusted to 7% or less. Shading shrink labels have been proposed.
JP-A-8-91385 (claim 4, paragraph number 0032, etc.) JP-A-9-328164 (Claims 3 to 4, pages 3 to 4 etc.) JP 2004-250040 A (Claims 1-3)

  However, in the method of protecting the contents by blending a low molecular weight UV absorber in the shrink film as described in Patent Documents 1 and 2, when the shrink film is used for pharmaceutical applications, it is used for disinfection. There is a problem that the ultraviolet absorber is extracted by alcohol. In addition, kneading a low molecular weight UV absorber into a synthetic resin film, and then processing such as stretching to form a UV-absorbing shrink film. Not only does the performance not fully develop, there is a risk that the ultraviolet absorber will elute in the container for storing the drug. Furthermore, if the amount of UV absorber is increased to an amount that can cut UV rays, the addition of the UV absorber will impair the transparency of the shrink film. There is also a problem that it cannot be added.

  Further, in the method of coating a shrink film with a coating liquid containing a low molecular weight ultraviolet absorber described in Patent Document 2, there is a problem that the coating is peeled off by friction or the film itself is whitened with alcohol. is there.

  On the other hand, the method of applying a light-shielding pigment (titanium oxide) as in the light-shielding shrink label described in Patent Document 3 requires dark coloring, so the visibility of the contents is inferior. Moreover, since the film is colored, label design is restricted. Furthermore, there is a problem that it is difficult to ensure uniform light shielding performance due to color unevenness. There is a similar problem in the method of adding a light-shielding pigment to the film and subjecting the film itself to a light-shielding process, and there is a concern about migration or elution of the pigment caused by using a large amount of the light-shielding pigment.

  Furthermore, a method of incorporating a low molecular weight ultraviolet absorber into the pressure-sensitive adhesive is also conceivable. However, as in the case where it is incorporated in the film itself, there is a possibility that the ultraviolet absorber may migrate and elute when used in a large amount. Moreover, since there is some coloring (yellow), there is also a defect that the contents appear to deteriorate.

  The present invention has been made to solve the above-mentioned conventional problems, and protects the contents of a plastic drug container so as not to be altered by ultraviolet light or low-wavelength visible light, and an ultraviolet absorber is placed inside the container. There is no risk of elution, and the contents can be easily seen from the outside without lowering the visibility of the contents as when applying light-shielding pigments. There is no label design restriction due to coloring, and stable light-shielding performance is maintained. An object of the present invention is to provide a light-shielding shrink tack sheet and a label using the same.

  As a result of intensive investigations to achieve the above object, the present inventors have provided a light-blocking pressure-sensitive adhesive layer in which a light-blocking substance is dispersed on one side of an ultraviolet-absorbing shrink film, so that ultraviolet light and low wavelength can be obtained. A shrink tack sheet suitable for pharmaceuticals having low visible light transmittance and excellent ultraviolet shielding properties and high visible light transmittance can be obtained. Further, as the ultraviolet absorbing shrink film, a high molecular weight ultraviolet absorbing polymer is shrinked. By using what was coated on one or both sides of the film, it was found that a light-shielding shrink tack sheet without elution into the plastic drug container to be coated or pasted was obtained, and the present invention was completed. .

That is, the present invention is as follows.
1) At least one UV-absorbing monomer selected from benzotriazole-based UV-absorbing monomers represented by the following formula (1) is contained as an essential component, and the polystyrene-equivalent number average molecular weight (Mn) is One of the ultraviolet-absorbing shrink films formed by applying an ultraviolet-absorbing acrylic copolymer having a glass transition temperature (Tg) of 0 to 100 ° C. to one or both sides of 10,000 to 30,000. A light-shielding shrink sheet provided with a light-shielding pressure-sensitive adhesive layer in which ultrafine metal oxides having an average particle diameter of 0.01 to 0.1 μm are dispersed on the surface, and has an ultraviolet transmittance of 5 in the ultraviolet region (390 nm). %, And a haze value is 40% or less.

(In the formula, R ²¹ represents a hydrogen atom, a halogen atom, or a methyl group. R ²² represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. R ²³ represents an alkylene group having 1 to 10 carbon atoms, Or an oxyalkylene group having 1 to 10 carbon atoms, and m ²¹ represents 0 or 1. R ²⁴ is an alkylene group having 1 to 8 carbon atoms, an alkylene group having 1 to 8 carbon atoms having an amino group, or a hydroxyl group. And an alkylene group having 1 to 8 carbon atoms, m ²² represents 0 or 1. R ²⁵ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, X ² represents an ester bond, an amide bond, or an ether. Indicates a bond or urethane bond.)
2) The light-shielding pressure-sensitive adhesive layer, alkyl ester acrylate copolymer, an isocyanate crosslinking agent, and described in 1) which is composed of ultrafine metal oxide having an average particle diameter 0.01~0.1μm Medical light-shielding shrink tack sheet,
3 ) The light-shielding shrink tack sheet for medical use according to 1) or 2) above, wherein the material of the shrink film is polyester, polyethylene, polypropylene, or polystyrene resin, and
4 ) A light-shielding shrink label produced using the pharmaceutical light-shielding shrink tack sheet according to any one of 1) to 3 ).

  According to the present invention, the contents of a plastic drug container can be protected from being altered by ultraviolet light or low-wavelength visible light, have high visible light transmittance, and have stable light-shielding performance. It is possible to provide a light-shielding shrink tack sheet that does not cause the absorbent to elute into the container, and a label using the same. Further, since the transparency of the sheet is ensured, the contents can be easily visually recognized from the outside, and there is no restriction on the label design.

  The light-shielding shrink tack sheet and the light-shielding shrink label of the present invention have excellent heat shrinkability, a low natural shrinkage rate at room temperature, and excellent workability.

  The light-shielding shrink tack sheet of the present invention is provided with a light-shielding pressure-sensitive adhesive layer in which a light-shielding substance is dispersed on one surface of an ultraviolet-absorbing shrink film, and has an ultraviolet transmittance in the ultraviolet light region (390 nm). Is 5% or less, and the haze value is 40% or less.

  As the ultraviolet absorbing shrink film in the present invention, uniaxial or biaxial stretching (simultaneous biaxial or sequential biaxial stretching) by calendering, T-die method, inflation method, roll stretching method, tenter stretching method, tubular stretching method, etc. A film obtained by coating an ultraviolet absorbing polymer on one or both sides of a shrink film having a thickness of about 25 to 80 μm is preferably used. When a low molecular weight UV absorber is applied to a film, the UV light shielding performance does not last for a long time because the coating is peeled off due to friction, and whitening occurs due to alcohol for disinfection. When the agent is contained in the film, the ultraviolet shielding effect is insufficient when added in a small amount, and when added in a large amount to maintain the effect, the additive may migrate to the contents. In the case of using an ultraviolet absorbing polymer, such a problem hardly occurs and there is an advantage that the effect is sustained for a long time.

  The raw material resin for the shrink film is preferably a resin having excellent transparency, and examples thereof include polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), polyethylene, polystyrene, polypropylene, vinyl chloride and the like. Among these resins, polyester, polyethylene, polypropylene, and polystyrene resins are preferable from the viewpoint of transparency and heat shrinkability.

  As the UV-absorbing polymer to be applied to the shrink film, UV-absorbing polymers having an UV-absorbing unit can be widely used, and among these, the benzotriazole-based UV-absorbing monomer represented by the above (Chemical Formula 1) is selected. An ultraviolet absorbing polymer obtained by copolymerizing 25 to 55% by mass of at least one ultraviolet absorbing monomer (A) as an essential component is preferable from the viewpoint of ultraviolet absorption characteristics and elution properties.

In the formula (1), examples of the alkylene group having 1 to 10 carbon atoms (R ²³ ) include a methylene group, an ethylene group, a trimethylene group, a propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, and an octamethylene group. And a decamethylene group, preferably an alkylene group having 1 to 6 carbon atoms (more preferably an alkylene group having 1 to 4 carbon atoms). Examples of the oxyalkylene group having 1 to 10 carbon atoms (R ²³ ) include an oxymethylene group, an oxyethylene group, and an oxypropylene group.

R ²³ may be substituted at any position in the benzene ring substituted with a hydroxyl group. A preferred substitution position for R ²³ is the 5-position.

Examples of the halogen atom (R ²¹ ) include a fluorine atom, a chlorine atom, and a bromine atom, and a chlorine atom is preferable. When R ²¹ is a halogen atom or a methyl group, R ²¹ may be substituted at any position in the benzene ring. Preferable R ²¹ includes a hydrogen atom.

In the hydrocarbon group having 1 to 6 carbon atoms (R ²² ), an alkyl group is preferably used as the hydrocarbon group. Such alkyl groups include those having 1 to 6 carbon atoms among the exemplified alkyl groups. R ²² may be substituted at any position in the benzene ring substituted with a hydroxyl group, and the preferred substitution position of R ²² is the 3-position.

Examples of the alkylene group having 1 to 8 carbon atoms (R ²⁴ ) include an alkylene group having 1 to 8 carbon atoms among the above-exemplified alkylene groups, preferably 1 to 4 carbon atoms (more preferably 1 to 4 carbon atoms). The alkylene group of 2) is mentioned. Moreover, as a C1-C8 alkylene group which has a C1-C8 alkylene group which has an amino group, or a hydroxyl group, what the amino group or the hydroxyl group substituted by the said alkylene group is mentioned. It is done.

X ² represents an ester bond, an amide bond, an ether bond, or a urethane bond. Specifically, —COO—, —OCO—, —NHCO—, —CONH—, —O—, —NHCOO—, — COONH- etc.

m ²¹ and m ²² represent 0 or 1. For example, when m ²¹ is 0, X ² is directly bonded to the benzene ring substituted with the hydroxyl group without R ²³ . When m ²² is 0, it means that X ² is directly bonded to the carbon atom to which R ²⁵ is bonded, not via R ²⁴ . That is, when m ²¹ or m ²² is 0, it means that R ²³ or R ²⁴ is not present. On the other hand, when m ²¹ or m ²² is 1, it means that R ²³ or R ²⁴ is present.

  More specifically, examples of the benzotriazole-based ultraviolet absorbing monomer represented by the formula (1) include 2- [2′-hydroxy-5 ′-(methacryloyloxy) phenyl] benzotriazole, 2- [2 ′]. -Hydroxy-5 '-(acryloyloxy) phenyl] benzotriazole, 2- [2'-hydroxy-3'-t-butyl-5'-(methacryloyloxy) phenyl] benzotriazole, 2- [2'-hydroxy- 3'-methyl-5 '-(acryloyloxy) phenyl] benzotriazole, 2- [2'-hydroxy-5'-(methacryloyloxypropyl) phenyl] -5-chlorobenzotriazole, 2- [2'-hydroxy- 5 '-(methacryloyloxyethyl) phenyl] benzotriazole, 2- [2'-hydroxy- '-(Acryloyloxyethyl) phenyl] benzotriazole, 2- [2'-hydroxy-3'-t-butyl-5'-(methacryloyloxyethyl) phenyl] benzotriazole, 2- [2'-hydroxy-3 ' -Methyl-5 '-(acryloyloxyethyl) phenyl] benzotriazole, 2- [2'-hydroxy-5'-(acryloyloxybutyl) phenyl] -5-methylbenzotriazole, [2-hydroxy-3-t- And butyl-5- (acryloyloxyethoxycarbonylethyl) phenyl] benzotriazole.

  The ultraviolet absorbing monomer (A) includes a 2-hydroxybenzotriazole skeleton and an ultraviolet absorbing compound having a functional group (hydroxyl group, carboxyl group, amino group, etc.) and a functional group (hydroxyl group, carboxyl group, amino group). Etc.) can be prepared by reacting and bonding (eg, ester bond, amide bond, ether bond, urethane bond) with a copolymerizable vinyl compound (such as acrylic acid or methacrylic acid).

  The ratio of the ultraviolet absorbing monomer (A) is preferably in the range of 25 to 55% by mass (hereinafter abbreviated as%), more preferably 25 to 40% with respect to the total amount of the monomer components. When the proportion of the monomer is less than 25%, the ultraviolet-grade yield decreases, and when it exceeds 55%, the low-temperature shrinkage decreases.

  In addition to the ultraviolet absorbing monomer (A), the monomer composition may be mixed with one or more other vinyl compounds copolymerizable therewith (hereinafter referred to as copolymerization monomer) (B). Examples of such a copolymerizable monomer (B) include acrylic acid esters, methacrylic acid esters, alkyl vinyl ethers, alkyl vinyl esters, and styrene.

More specifically, examples of the acrylic acid ester or methacrylic acid ester include acrylic acid-C _1-4 alkyl ester such as methyl acrylate, ethyl acrylate, and butyl acrylate, and methacrylic acid-C ₁ such as methyl methacrylate and ethyl methacrylate. _-2 alkyl esters. Examples of the alkyl vinyl ether include C _1-2 alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether. Examples of the alkyl vinyl ester include C _1-3 alkyl vinyl esters such as vinyl acetate, propionate vinyl and butyrate vinyl ester. Of these, acrylic acid-C _1-4 alkyl ester, methacrylic acid-C _1-2 alkyl ester and vinyl acetate are preferable from the viewpoint of improving the physical properties of the film.

  The proportion of the copolymerizable monomer (B) is preferably in the range of 45 to 75%, more preferably 60 to 75% with respect to the total amount of the monomer components.

  Moreover, the functional group containing monomer (C) which has functional groups, such as a carboxyl group, a hydroxyl group, and an amino group, can also be used as a copolymerization monomer other than the above. By copolymerizing such a functional group-containing monomer, the film strength of the polymer and the adhesion to the resin surface can be improved.

  Examples of the functional group-containing monomer (C) include α, β-unsaturated mono- or dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid; 2-hydroxyethyl acrylate, 2- Hydroxyl group-containing (meth) acrylic acid esters such as hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl acrylate; Polyalkylene glycol (meth) acrylic acid esters such as diethylene glycol monomethacrylate and polyethylene glycol monomethacrylate; And (meth) acrylic acid esters. Of these, methacrylic acid and 2-hydroxyethyl methacrylate are preferred from the viewpoint of excellent adhesion.

  The ratio of the functional group-containing monomer (C) is preferably in the range of 0.001 to 15%, more preferably 0.01 to 10% with respect to the total amount of the monomer components.

  The above UV-absorbing acrylic copolymer is excellent in shrinkage at a heating temperature (40 to 150 ° C.) at the time of shrink wrapping, and has a good finished appearance after being mounted. From the point that wrinkles do not occur, those having a polystyrene-equivalent number average molecular weight (Mn) in the range of 10,000 to 30,000 and a glass transition temperature (Tg) of 0 to 100 ° C. are preferable. Mn is a value measured by gel permeation chromatography (GPC). If the number average molecular weight (Mn) is 10,000 or more, there is no fear of elution into the contents, and if it is 30,000 or less, the transparency of the film is not inferior.

  The Tg of the acrylic copolymer of the UV-absorbing polymer is preferably in the range of 0 ° C to 100 ° C, more preferably 15 ° C to 80 ° C, and even more preferably in the range of 20 ° C to 75 ° C. . When the Tg of the acrylic copolymer is within the above temperature range, it has an appropriate softening point suitable for low-temperature processing. However, when the Tg is too low, it shrinks during storage and cannot be put to practical use. There is a fear. On the other hand, when Tg is too high, it must be shrunk at a high temperature, and the medicine may be altered during the shrinking process, which makes it unsuitable for pharmaceutical packaging applications.

  The ultraviolet-absorbing acrylic copolymer can be produced by a usual polymerization method such as a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method.

  For example, in the case of preparing by a solution polymerization method, a monomer composition containing the above monomer such as an ultraviolet absorbing monomer may be polymerized in a suitable solvent in the presence of a polymerization initiator. Examples of the polymerization solvent include known solvents such as esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as benzene, toluene and xylene, ketones such as acetone, cyclohexane and methyl ethyl ketone, and ethers such as tetrahydrofuran. It can be used alone or in combination of two or more. As the polymerization initiator, known compounds such as peroxides such as benzoyl peroxide and azo compounds such as azobisisobutyronitrile can be used alone or in admixture of two or more. Although the usage-amount of a polymerization initiator is not specifically limited, It is good to set it as about 0.05-2% of a monomer composition.

  Moreover, when preparing by an emulsion polymerization method, it can prepare by emulsifying a monomer component using an emulsifier as needed, and performing emulsion polymerization in presence of a polymerization initiator, and is used by emulsion polymerization. The emulsifier and polymerization initiator to be used are not particularly limited, and known ones can be used.

  When the ultraviolet absorbing acrylic copolymer is applied to the shrink film to form the ultraviolet absorbing shrink film, the ultraviolet absorbing acrylic copolymer is applied to the surface of the shrink film. The copolymer may be diluted with a polymerization solvent or a dilution solvent. In addition, the coating agent may contain additives such as a hydrolysis inhibitor, an antioxidant, an antifungal agent, an antifoaming agent, a pigment, and a vehicle, as long as the object of the present invention is not impaired. . The coating method is not particularly limited, and a brush coating method, a spray coating method, a dipping method, a flow coating method, and the like can be employed. After coating, heat treatment is appropriately performed to remove the solvent, and a polymer film is formed on the surface of the shrink film. The thickness of the polymer film is preferably 1 to 10 μm, more preferably 2 to 5 μm, in terms of the film thickness after drying. If the film thickness is 1 μm or more, the ultraviolet absorption characteristics are good, and if the film thickness is 10 μm or less, the adhesion of the shrink film does not decrease.

  Next, a light-shielding pressure-sensitive adhesive layer in which a light-shielding substance is dispersed is formed on one side of the ultraviolet-absorbing shrink film formed by the above method. By forming the light-shielding pressure-sensitive adhesive layer, it is possible to avoid poor visibility of the contents, which is a drawback of shrink films containing or coating a light-shielding pigment on the film, and the transparency of the film and stable light-shielding performance In addition, since there is no design restriction, it can be applied to various pharmaceutical containers.

  1 and 2 are schematic cross-sectional views showing structural examples of the light-shielding shrink tack sheets 10 and 20 according to the present invention, in which 1 is an ultraviolet-absorbing shrink film, 11 is a shrink film, and 12 is an ultraviolet-absorbing polymer. 2 is a light-shielding pressure-sensitive adhesive layer.

  Examples of the pressure-sensitive adhesive that forms the light-blocking pressure-sensitive adhesive layer include acrylic resin-based, rosin-based, rubber-based, and vinyl-based pressure-sensitive adhesives. An acrylic pressure-sensitive adhesive is preferred from the viewpoint of little change in force and excellent transparency.

  As said acrylic adhesive, the alkyl acrylate obtained by superposing | polymerizing 1 type, or 2 or more types of acrylic ester which has a C4-C18 alkyl group, and a monomer copolymerizable with these monomers An ester copolymer is preferably used. Examples of copolymer monomers include monomers that do not have reactive functional groups such as acrylonitrile, alkyl methacrylates, alkyl vinyl ethers, alkyl vinyl esters, and styrene, and reactive functional group-containing monomers. Specific examples of these compounds include The following are mentioned.

(1) Acrylic acid alkyl ester / methacrylic acid alkyl ester having an alkyl group having 4 to 18 carbon atoms: butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, stearyl acrylate, methyl methacrylate, butyl methacrylate, t-butyl methacrylate , 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate (2) alkyl vinyl ether methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, stearyl vinyl ether (3) alkyl vinyl ester vinyl acetate, ethyl vinyl, butyl vinyl, 2-ethylhexyl vinyl

Specific examples of the reactive functional group-containing monomer include the following.
(4) Hydroxy group-containing monomer Hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, polyoxyethylene monoacrylate, polyoxypropylene monomethacrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate

  The pressure-sensitive adhesive used in the present invention can be a cohesive copolymer by changing the type and ratio of the copolymerization monomer used. In addition, by copolymerizing a highly rigid copolymerization monomer, for example, a copolymerization monomer having a rigid functional group such as a methyl group or a benzene ring introduced into the side chain, such as methyl methacrylate, styrene, and vinyl acetate. A slightly tacky copolymer can be obtained.

  When producing an adhesive, it is preferable to prepare from a monomer mixture in which an alkyl acrylate ester having an alkyl group having 4 to 18 carbon atoms is an essential component, and a copolymerization monomer is mixed as necessary. It is desirable to contain 50% or more of an adhesive copolymer monomer having 4 to 12 carbon atoms in the alkyl group. When the amount of the acrylic acid alkyl ester is less than 50%, the tackiness is decreased, and it may be difficult to obtain the target pressure-sensitive adhesive. However, when acidic monomers such as acrylic acid and methacrylic acid are copolymerized, the above-mentioned acidic monomer should not be included as a constituent of the copolymer because the phenomenon of polymer aggregation appears when a light-shielding substance is added. Is preferred.

  Moreover, in the adhesive copolymer, since the cohesiveness of the copolymer tends to be insufficient, an isocyanate-based crosslinking agent is preferably used in combination for the purpose of improving removability. Specific examples of the isocyanate-based crosslinking agent include, for example, an adduct of tolylene diisocyanate (3 mol) and trimethylolpropane (1 mol), an adduct of hexamethylene diisocyanate (3 mol) and trimethylolpropane (1 mol), Examples thereof include polyisocyanate compounds such as an adduct of isophorone diisocyanate (3 mol) and trimethylolpropane (1 mol) and an adduct of xylene diisocyanate (3 mol) and trimethylolpropane (1 mol).

  When forming the light-shielding pressure-sensitive adhesive layer of the present invention, an acrylic acid alkyl ester copolymer, an isocyanate cross-linking agent, and a light-shielding substance are mixed to prepare a coating solution having an appropriate solid content concentration and applied onto a release paper. The pressure-sensitive adhesive layer is formed by drying. As for the addition amount of the said crosslinking agent, 0.1-5.0 mass parts is preferable with respect to 100 mass parts (solid content conversion) of an acrylic acid alkylester copolymer.

  Moreover, 1.0-7.5 mass parts is preferable with respect to 100 mass parts (in terms of solid content) of the acrylic acid alkyl ester copolymer, and more preferably 2.0-4. 0 parts by mass. When the addition amount of the light-shielding substance is too small, the light-shielding effect is insufficient. On the other hand, when the addition amount of the light-shielding substance is too large, the haze value of the shrink label and the sheet is increased and the light transmittance is decreased.

  As the light-shielding substance, an ultrafine metal oxide having an average particle size of 0.01 to 0.1 μm is preferable, and both the light-shielding property and the transparency are provided as long as the average particle size is within the above range. A light-shielding shrink film can be formed. The average particle diameter of the ultrafine metal oxide is more preferably 0.01 to 0.05 μm. Examples of the metal oxide include titanium oxide and zinc oxide. Among metal oxides, titanium oxide is particularly preferable in terms of ultraviolet light shielding properties and transparency.

  In the case of manufacturing a light-shielding shrink tack sheet, a light-shielding pressure-sensitive adhesive layer in which the above-mentioned light-shielding substance is dispersed is formed on one side of an ultraviolet-absorbing shrink film, and then cut to a desired size to produce a light-shielding shrink tack sheet. And The obtained light-shielding shrink tack sheet has an ultraviolet transmittance in the ultraviolet region (390 nm) of 5% or less and a haze value of 40% or less. The ultraviolet transmittance is more preferably 3% or less, particularly preferably 1.5% or less. The haze value is more preferably 30% or less, and particularly preferably 25% or less.

  When the light-shielding shrink tack sheet and the label of the present invention are coated or pasted on a pharmaceutical container, the container equipped with the label is passed through a heating furnace having an atmospheric temperature of 40 to 150 ° C. and shrink-wrapped by a conventional method. . FIG. 3 shows an example of a shrink wrapping process diagram of the medical container 30 using the shrink tack sheet of the present invention.

  The light-shielding shrink tack sheet and label of the present invention can be preferably used for packaging plastic pharmaceutical containers, and can also be used for packaging cosmetic containers, food containers and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, the scope of the present invention is not limited only to an Example. The evaluation methods used in the examples are as follows.

(Test Example 1: Heat shrinkage rate)
The shrink film prepared in Preparation Examples 1 to 3 described later is cut into a 100 mm square to make a sample, and after immersing this sample in a warm water bath adjusted to a predetermined temperature for 30 seconds, the vertical or horizontal dimensions are measured, Each thermal contraction rate was calculated | required according to the following formula.

(Test Example 2: Natural shrinkage rate)
The maximum shrinkage after storing the sample in a thermostatic chamber at 35 ° C. for 30 days was defined as the natural shrinkage.

(Test Example 3: Alcohol resistance)
Each shrink tack sheet prepared in the examples was immersed in ethanol at room temperature for 2 hours, and then the ultraviolet absorption characteristics (Test Example 6) and transparency (Test Example 7) were confirmed.

(Test Example 4: Number average molecular weight)
It was determined by liquid chromatography (GPC). In the GPC, as a column, a product name “TSKGel GMHXL (manufactured by Tosoh Corporation)” × 2 and a product name “TSKGel G2000HXL (manufactured by Tosoh Corporation)” × 1, tetrahydrofuran as a mobile phase, and differential refraction as a detector are used. Rate meter The product name “RI-8000” was used. Measurement conditions are a temperature of 40 ° C. and a flow rate of 0.8 ml / min.

(Test Example 5: Adhesive properties)
(1) Tackiness: Based on the Dow method (23 ± 2 ° C., 65 ± 5% RH).
(2) Adhesive strength: The sample was cut into 25 mm × 120 mm, and was pressed back and forth 3 times with a 2 kg rubber roller on a stainless steel plate (SUS-304) at room temperature of 23 ± 2 ° C. and 65 ± 5% RH, and left for 1 hour. Then, it measured with the tension | pulling speed of 300 mm / min in the 180 degree direction with the tension tester.
(3) Holding power: The sample is cut 25 mm × 120 mm, and in a greenhouse of 23 ± 2 ° C. and 65 ± 5% RH, the adhesion area is 25 mm × 25 mm at one end of the stainless steel plate (SUS-304). 3 reciprocating pressures were applied with a 2 kg rubber roller, and after left for 1 hour, a load of 4.9 N was applied in an atmosphere at 70 ° C., and the shift length or drop time after 24 hours was measured.

(Test Example 6: UV absorption characteristics)
The sample was cut into 40 mm × 50 mm, and the transmittance (% T) at 390 nm of the adhesive film was measured using a Hitachi U-3300 spectral photometer.

(Test Example 7: Transparency)
In accordance with JIS K 7105, the haze value was measured using VGS-300A manufactured by Nippon Denshoku Industries Co., Ltd.

(Preparation Example 1: Preparation of UV-absorbing shrink film)
In a 300 ml separable flask equipped with a Dimroth, dropping funnel, thermometer, nitrogen inlet tube, and stirring device, 30.0 g of 2- [2′-hydroxy-5 ′-(methacryloyloxy) phenyl] benzotriazole, methyl methacrylate 50 g, 15 g of butyl acrylate, 2 g of methacrylic acid, 0.5 g of 2-hydroxyethyl methacrylate, 1.6 g of n-dodecyl mercaptan and 100 g of ethyl acetate were added, and the temperature was raised to 50 ° C. while blowing nitrogen from the nitrogen introduction tube. Thereafter, 0.3 g of azobisisobutyronitrile dissolved in a small amount of ethyl acetate was added dropwise over 30 minutes. After the completion of the addition, the temperature was raised to 70 ° C., and the reaction was carried out for 8 hours. A coalescence was prepared. The UV-absorbing acrylic copolymer was applied to a 50 μm-thick shrink polyethylene terephthalate (Ci Kasei Co., Ltd., Bon Set) to a dry film thickness of 5 μm, and then dried at 60 ° C. for 30 seconds. A UV-absorbing shrink film was prepared.

(Preparation Examples 2-3)
Except for the monomer composition shown in Table 1, polymerization was performed in the same manner as in Preparation Example 1 to prepare an ultraviolet-absorbing acrylic copolymer, and an ultraviolet-absorbing shrink film was prepared in the same manner as in Preparation Example 1. Prepared.

(Preparation Example 4: Preparation of light-shielding pressure-sensitive adhesive)
Dim funnel, dropping funnel, thermometer, nitrogen inlet tube, 300 ml separable flask equipped with a stirrer were added 55 g of 2-ethylhexyl acrylate, 25 g of vinyl acetate, 4 g of 2-hydroxyethyl methacrylate and 100 g of ethyl acetate, and a nitrogen inlet tube Then, the temperature was raised to 50 ° C. while blowing nitrogen. Thereafter, 0.3 g of azobisisobutyronitrile dissolved in a small amount of ethyl acetate was added dropwise over 30 minutes, and after completion of the addition, the temperature was raised to 70 ° C., and the reaction was carried out for 8 hours. A solution was prepared.
1 part by weight of titanium oxide having an average particle size of 0.03 μm was blended with 100 parts by weight of the adhesive acrylic copolymer solution, and was dispersed for 1 hour by a three-roll mill. After dispersion, 0.13 parts by weight of Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd., isocyanate-based crosslinking agent) was blended to prepare a light-shielding pressure-sensitive adhesive.

(Preparation Examples 5 to 9)
A light-shielding pressure-sensitive adhesive was prepared in the same manner as in Preparation Example 4 except that the monomer composition and the ultrafine particles were changed to the compositions shown in Table 2.

Example 1
The light-shielding pressure-sensitive adhesive prepared in Preparation Example 4 was applied to release paper (SP-8E, manufactured by Lintec Corporation) with an applicator so that the dry film thickness was 25 μm, and the circulating hot air dryer at 100 ° C. for 2 minutes. Dried. After drying, it was adhered to the ultraviolet absorbing shrink film prepared in Preparation Example 1 to prepare a light shielding shrink tack sheet for medical use.

(Examples 2-4, Comparative Examples 1-3)
A pharmaceutical light-shielding shrink tack sheet was prepared in the same manner as in Example 1 except that the ultraviolet-absorbing shrink film and the light-shielding pressure-sensitive adhesive had the composition shown in Table 3.

As is clear from Table 3, the light-shielding shrink tack sheet according to the present invention has an ultraviolet transmittance at 390 nm of 5% or less, a haze value of 40% or less, good ultraviolet absorption characteristics and excellent transparency. It was what was. On the other hand, the light-shielding shrink tack sheet of the comparative example could not be obtained which satisfies the ultraviolet absorption characteristics and the transparency at the same time. Moreover, when a low molecular weight ultraviolet absorber was used (Comparative Example 2), the ultraviolet absorption property was inferior, and the ultraviolet absorption property and the transparency after ethanol immersion were significantly reduced.

It is a cross-sectional schematic diagram which shows the structural example of the shrunk tack sheet | seat for pharmaceuticals of this invention. It is a cross-sectional schematic diagram which shows the structural example of the shrunk tack sheet | seat for pharmaceuticals of this invention. It is a shrink wrapping process figure of a medical container.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultraviolet-absorbing shrink film 11 Shrink film 12 Ultraviolet-absorbing polymer layer 2 Light-shielding pressure-sensitive adhesive layers 10 and 20 Light-shielding shrink tack sheet 30 Pharmaceutical container

Claims (4)

It contains at least one UV-absorbing monomer of 25 to 55% by mass selected from benzotriazole-based UV-absorbing monomers represented by the following formula (1) as an essential component, and has a polystyrene equivalent number average molecular weight (Mn) of 10,000. On one side of an ultraviolet-absorbing shrink film formed by coating an ultraviolet-absorbing acrylic copolymer having a glass transition temperature (Tg) of 0 to 100 ° C. on one side or both sides of ˜30,000. A light-shielding shrink sheet provided with a light-shielding pressure-sensitive adhesive layer in which ultrafine metal oxides having an average particle size of 0.01 to 0.1 μm are dispersed, and the ultraviolet transmittance in the ultraviolet region (390 nm) is 5% or less And the haze value is 40% or less, The light-shielding shrink tack sheet | seat for pharmaceuticals characterized by the above-mentioned.

(In the formula, R ²¹ represents a hydrogen atom, a halogen atom, or a methyl group. R ²² represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. R ²³ represents an alkylene group having 1 to 10 carbon atoms, Or an oxyalkylene group having 1 to 10 carbon atoms, and m ²¹ represents 0 or 1. R ²⁴ is an alkylene group having 1 to 8 carbon atoms, an alkylene group having 1 to 8 carbon atoms having an amino group, or a hydroxyl group. And an alkylene group having 1 to 8 carbon atoms, m ²² represents 0 or 1. R ²⁵ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, X ² represents an ester bond, an amide bond, or an ether. Indicates a bond or urethane bond.) The medicament according to claim 1 , wherein the light-shielding pressure-sensitive adhesive layer comprises an alkyl acrylate copolymer, an isocyanate-based crosslinking agent, and an ultrafine metal oxide having an average particle size of 0.01 to 0.1 µm. Shading shrink tack sheet. The medical light-shielding shrink tack sheet according to claim 1 or 2 , wherein the material of the shrink film is polyester, polyethylene, polypropylene, or polystyrene resin. A light-shielding shrink label produced using the pharmaceutical light-shielding shrink tack sheet according to any one of claims 1 to 3 .