JP2019048470A - Heat shrinkable film, molded article using the film, heat shrinkable label, and container fitted with the molded article or the label - Google Patents

Abstract

To provide a heat shrinkable film that is excellent in film appearance such as aesthetics, clarity and glossy feeling, has a high level of a light shielding property, and is excellent in a finishing property after shrinkage.SOLUTION: Provided is a heat shrinkable film made by drawing in at least one direction. The heat-shrinkable film is characterized that: the percentage of a wavelength region, in which light transmittance at a wavelength of 200 to 500 nm is 5% or less, is 50% or more; the light reflectance at the wavelength of 200 to 500 nm is 30% or less; the glossiness is 90% or more; and the surface roughness is 60 nm or less.SELECTED DRAWING: None

Description

The present invention relates to a heat-shrinkable film, a molded article using the film, a heat-shrinkable label, and the molded article or a container equipped with the label. Specifically, a heat-shrinkable film which is excellent in film appearance such as aesthetics, sharpness and gloss, has a high level of light-shielding property, and has a good shrink finish on a container, and a molded article using the film, heat shrink And a molded article or a container equipped with the label.

BACKGROUND ART Conventionally, glass or plastic containers colored to impart light shielding properties have been widely used as containers for beverages that are easily degraded by light. However, since these containers contain a coloring agent will be a big obstacle in the recovery and reuse of used containers, the technology to give a light shielding property by attaching a film with a light shielding property to a transparent container is examined It is done.
In the case of heat-shrinkable label applications for packaging, etc., in addition to the light shielding property, the appearance of the label represented by the sharpness and glossiness of the design is also important. In addition, in the case of heat shrinkable label applications for beverage packaging, it is particularly used for beverage packaging labels that are susceptible to discoloration or deterioration by light of a specific wavelength range, such as alcoholic beverages such as beer, sake, wine, green tea, and vitamin-containing beverages. When it is used, a high level of light shielding performance is required together with the appearance of labels such as design clarity and gloss, and the state of the contents and the liquid level can be confirmed for the purpose of preventing tampering with foreign matter mixing etc. Is required.

As a film used for such an application, Patent Document 1 discloses a heat-shrinkable label using a white film containing titanium dioxide or the like. In the heat-shrinkable label using the white film, the light-shielding property can be secured, but since there is a light-shielding property of visible light such that the color is not transparent to the front when back printing is performed, the condition of the contents of the container or It is extremely difficult to check the liquid level, which is not preferable from the viewpoint of tampering prevention.

Patent Document 2 discloses a shrink label in which a white heat-shrinkable film is black-printed. In the case of such a film configuration, since the inner surface which is in contact with the bottle is black, there is a problem that the beverage looks blackish when the beverage of the contents is viewed from the mouth of the bottle. Moreover, in the case of such colored printing, in order to improve the light shielding property, it is necessary to increase the number of times of printing or to provide a high density printing layer. However, the demerit such as the cost increase and the deterioration of the film surface occurs, and it can not be said that it is an effective processing method.

Further, Patent Document 3 discloses a colored transparent shrink label in which a print layer is provided on a film formed of a layer containing a colorant on both sides of a transparent layer. However, such films have high surface roughness of the film, and it is difficult to obtain sharpness and gloss.

In addition, as a method of attaching a label, it is known that covering the entire target container such as a PET bottle with a label is effective for light shielding. However, PET bottles in recent years have complicated outer shapes, and there are also cases where the difference in outer periphery between the body and the plug is large, and the above-mentioned films and the like that have been studied have shrinkage rates due to repeated printing. It has been difficult to obtain a good finished appearance after shrinkage, such as a decrease or failure to follow the outer shape of the bottle cleanly, shrinkage spots and wrinkles, etc.

As described above, labels used for containers for beverages etc. are important not only for functionality but also for their appearance, beauty in appearance, luxury, etc., and design that inspires consumers to buy is required . For example, there is a demand to express the glossiness and luxury like a glass bottle, and the familiarity when picked up. However, in the conventional white films and printing films as described above, those satisfying high design properties have not been obtained, and it is also difficult to achieve both of the functionality as a label.

JP 2002-285020 A Japanese Patent Application Publication No. 2003-26252 Unexamined-Japanese-Patent No. 2003-271062

The object of the present invention is to solve such conventional problems and provide it at low cost, and it is excellent in film appearance such as aesthetics, sharpness and gloss, and has a high level of light-shielding property, It is an object of the present invention to provide a heat-shrinkable film which is excellent in finish after shrinkage.

Another object of the present invention is to provide a molded article using the heat shrinkable film, a heat shrinkable label, and a product using the molded article or a heat shrinkable label suitable for applications such as a heat shrinkable label. To provide a container.

As a result of intensive investigations in view of the above problems, the present inventors have achieved the above objects by means of a heat shrinkable film in which the light transmittance and the light reflectance are in a specific range, and the glossiness and surface roughness are in a specific range. The present invention has been completed.

That is, the gist of the present invention resides in the following [1] to [9].
[1] A heat-shrinkable film drawn in at least one direction, wherein the film has a ratio of 50% or more of a wavelength region in which the light transmittance is 5% or less at a wavelength of 200 to 500 nm, and A heat shrinkable film characterized by having a light reflectance of 30% or less at 200 to 500 nm, a gloss of 90% or more, and a surface roughness of 60 nm or less.

[2] The heat-shrinkable film according to the above [1], having at least one layer containing a colorant.
[3] The heat-shrinkable film according to the above [1] or [2], wherein the thickness of the layer containing the colorant is 30 to 98% with respect to the total thickness of the film.
[4] The heat shrinkable film according to any one of the above [1] to [3], wherein the heat shrinkage rate in the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds is 20% to 80%.
[5] The heat-shrinkable film according to any one of the above [1] to [4], having at least one layer containing a polyester resin as a main component.
[6] The heat-shrinkable film according to [5], wherein the polyester resin is a mixture containing the following (A) and / or (B).
(A) A polyester-based resin in which the dicarboxylic acid component contains terephthalic acid as the main component, the diol component contains ethylene glycol as the main component, and further contains any one or more of 1,4-cyclohexanedimethanol, diethylene glycol and neopentyl glycol (B) The dicarboxylic acid component contains terephthalic acid as the main component, and as a diol component, ethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol, 1,3-propanediol, 1,4-butanediol, poly Polyester-based resin [7] containing at least one or more selected from trimethylene glycol [7] A molded article having the heat-shrinkable film according to any one of [1] to [6] as a substrate.
[8] A heat-shrinkable label having the heat-shrinkable film according to any one of the above [1] to [6] as a substrate.
[9] A container using the molded article according to the above [7] or attached with the heat-shrinkable label according to the above [8].

According to the present invention, a heat-shrinkable film is provided which is excellent in film appearance such as aesthetics, sharpness and gloss, and has high light-shielding properties and good shrink characteristics such as finish after shrinkage. be able to.

Furthermore, according to the present invention, a molded article, a heat-shrinkable label, the above-mentioned molded article, or a molded article using the above-mentioned heat-shrinkable film excellent in beauty, sharpness, glossiness, light-shielding property and finish after shrinkage. A container fitted with a heat shrinkable label can be provided.

Hereinafter, the heat-shrinkable film, the molded article, the heat-shrinkable label, and the container of the present invention (hereinafter, the "film of the present invention", "the molded article of the present invention", "the label of the present invention", "the present invention Container)) will be described in detail.

[Film of the Invention]
The film of the present invention is a heat-shrinkable film which is stretched in at least one direction, and the film has a ratio of 50% or more of a wavelength region in which the light transmittance is 5% or less at a wavelength of 200 to 500 nm. And, at a wavelength of 200 to 500 nm, the light reflectance is 30% or less, the glossiness is 90% or more, and the surface roughness is 60 nm or less.

<Light transmittance>
In the film of the present invention, it is important that the wavelength range in which the light transmittance is 5% or less at a wavelength of 200 to 500 nm is 50% or more. 70% or more is preferable, 80% or more is more preferable, and 90% or more is further more preferable.
In the film of the present invention, the wavelength range in which the light transmittance is 20% or less at a wavelength of 200 to 500 nm is preferably 60% or more, and the wavelength range of 20% or less is more preferably 80% or more, 90% or more is more preferable.
By setting the light transmittance in the above range, it is used as a label for beverages, in particular, beverages such as beer, sake, alcoholic beverages such as wine, etc., green tea, beverages containing vitamins, etc. Etc., sufficient light shielding performance can be obtained, and at the same time, the aesthetics, sharpness and glossiness required for beverage labels can be obtained, and the light shielding property and appearance as a label can be obtained. It becomes possible to achieve both. The range of the light transmittance can be adjusted by the type and the content ratio of the colorant, the thickness of the layer containing the colorant, and the like.

<Ray Reflectivity>
It is important that the film of the present invention has a light reflectance of 30% or less at a wavelength of 200 to 500 nm. 200-550 nm is preferable and, as for the range whose light reflectivity is 30% or less, 200-600 nm is more preferable. By setting the light ray reflectance in the above range, it is possible to confirm the state of the contents in the container and the liquid level, which is preferable from the viewpoint of preventing tampering. The range of the light reflectance can be adjusted by the type and the content ratio of the coloring agent, the thickness of the layer containing the coloring agent, and the like.

The film of the present invention is preferably a layer in which at least one layer contains a colorant. The layer containing a colorant contains, as a main component, a resin that is a main component of the film of the present invention described later, and contains a colorant.
<Colorant>
The colorant used in the film of the present invention is not particularly limited as long as it can color the film, and may be a pigment or a dye, but is preferably a pigment based colorant, and is preferably an inorganic pigment or an organic pigment. The pigments are used alone or in combination to impart the desired color tone and light blocking properties. Specifically, red-based pigments, yellow-based pigments, blue-based pigments, green-based pigments, brown-based pigments, etc. can be used to express various color tones. In addition, white pigments and black pigments can be used to improve the hiding power and the light shielding properties.
Examples of red pigments include inorganic pigments such as cadmium red, cadmium mop red, chromium red, vermillion and bengala; organic pigments such as azo pigments, alizarin lake, quinacridone and cochineal lake perylene. Examples of yellow pigments include inorganic pigments such as yellow aker, aureoline, cadmium yellow, cadmium orange, chromium yellow, zinc yellow, naples yellow and nickel yellow; and organic pigments such as azo pigments and greenwich yellow. Ru. Examples of blue pigments include inorganic pigments such as ultramarine, rock ultramarine, and cobalt; and organic pigments such as phthalocyanine, anthraquinone, and indikoid. Examples of green pigments include inorganic pigments such as Cinavar green, cadmium green and chromium green; and organic pigments such as phthalocyanine, azomethine and perylene. Examples of the tea-based pigment include inorganic pigments such as amber, rho umber, burnt umber, yellow aker, van dike brown, chenna, rhoena, vern shena, bengara, and organic pigments such as sepia. Examples of white pigments include inorganic pigments such as titanium oxide, zinc oxide, lithopone and the like. As a blackish pigment, carbon black is mentioned as a representative example.
Among these, it is preferable to use a colored pigment from the viewpoint of light shielding performance, beautifulness and sharpness, among which a brown pigment and a green pigment are more preferable, and a brown pigment is more preferable.
These colorants may be used alone or in combination of two or more. Further, metal fine particles may be further added to these colorants. The colorant may be subjected to various dispersion processes by various known methods.

The content of the coloring agent in the layer containing the coloring agent of the film of the present invention can be appropriately selected in consideration of the light shielding property of the film, cost and the like, but the lower limit is preferably 0.1% by mass or more, more preferably The upper limit is preferably 25% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less. If the content of the coloring agent is within the above range, the light shielding performance of the film of the present invention will be sufficient, and it is preferable because the balance with the cost can be achieved.

<Glossiness>
It is important that the film of the present invention has a gloss value of 90% or more. If the glossiness is 90% or more, the sharpness and the gloss of the film are not lost, the film appearance after shrinkage is excellent, and the luxury of the product is not impaired, which is preferable. The glossiness can be adjusted by the layer constitution, the amount of the colorant added and the constitution of the resin.

<Surface roughness>
It is important that the film of the present invention has a surface roughness of 60 nm or less. The surface roughness is preferably 50 nm or less, and more preferably 40 nm or less. If the surface roughness is within the above range, the film is not hazy, and a good film appearance excellent in sharpness and gloss can be obtained, which is preferable. The surface roughness can be adjusted by the layer constitution, the addition amount of the colorant, and the constitution of the resin.

<Color difference (L * value, a * value, b * value)>
The film of the present invention preferably has an L * value of 10 or more, more preferably 30 or more, and still more preferably 50 or more. The b * value is preferably 0 or more, more preferably 20 or more, and still more preferably 40 or more. The a * value is not particularly limited. If a color difference is in the said range, since the film excellent in light-shielding property can be obtained, it is preferable. The color difference can be adjusted by the type and content ratio of the colorant.

<Laminated constitution of the film of the present invention>
When the film of the present invention is a heat-shrinkable film in which at least one layer contains a colorant, it is preferable to laminate a layer containing no colorant on one side or both sides of the layer containing a colorant. Also, if necessary, additional layers can be added as long as the effects of the present invention are not impaired.
The lower limit of the thickness ratio of the film of the present invention to the total thickness of the layer containing the colorant is preferably 30% or more, more preferably 40% or more, further preferably 50% or more, and the upper limit is 98% or less Is preferable, 95% or less is more preferable, and 90% or less is more preferable. If the thickness ratio of the layer containing a colorant is within the above range, the balance between the sharpness and the glossiness and the light shielding performance of the film of the present invention can be suitably made preferable.

The total thickness of the film of the present invention is not particularly limited as long as the effects of the present invention are not impaired, but preferably 10 to 200 μm, more preferably 12 to 150 μm, and still more preferably 15 to 120 μm.

<Heat shrinkage rate>
The heat shrinkage ratio is a percentage value representing the ratio of the shrinkage amount to the original size before shrinkage in the longitudinal direction or the lateral direction, as described later. This is an index for determining the adaptability to a shrinking process in a relatively short time (several seconds to several tens of seconds), such as the use of shrink labels for PET bottles. The “main shrinkage direction” means the larger one of the stretching ratio in the longitudinal direction and the lateral direction, and for example, when it is mounted on a bottle, it is a direction corresponding to the outer peripheral direction.
The film of the present invention preferably has a thermal shrinkage in the main shrinkage direction of 20% to 80% when immersed in warm water at 80 ° C. for 10 seconds. The lower limit of the heat shrinkage ratio in the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds is more preferably 25% or more, still more preferably 30% or more, and the upper limit is more preferably 75% or less More preferably, it is 70% or less.
In addition, when using the film of this invention for uses, such as a full shrink label, it is preferable to make the heat contraction rate of the main contraction direction 40% or more when making it immersed in warm water of 80 degreeC for 10 seconds. If it is 40% or more, it is preferable because even if the entire plastic bottle is covered, no wrinkles and the like occur up to the top of the lid, and a good shrink finish excellent in appearance can be obtained.
The heat shrinkage rate in the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds of the film of the present invention may be made a desired heat shrinkage rate by appropriately adjusting the stretching temperature and the stretching ratio at the time of film production. it can.

  At present, as a shrinking processing machine that is most widely used industrially for plastic bottle label attachment applications, it is generally called a steam shrinker using steam as a heating medium for shrinking processing. Furthermore, the heat shrinkable film needs to be sufficiently heat shrunk at a temperature as low as possible in view of the influence of heat on the object to be coated and the like. However, in the case of a film having a high temperature dependency and an extremely different shrinkage rate depending on the temperature, it is easy to generate a site having a different shrinkage behavior with respect to a temperature spot in the steam shrinker, so wrinkles, spots, avatars and the like occur. There is a tendency for the shrinkage finish appearance to deteriorate. From the viewpoint including these industrial productivity, if the heat shrinkage rate in the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds is 20% or more, adhesion to the object to be coated sufficiently within the shrinkage processing time And it is preferable because wrinkles, spots, avatars and the like do not occur and a good shrink finished appearance can be obtained.

Furthermore, by suppressing the contraction rate in the direction orthogonal to the main contraction direction, it is possible to obtain more excellent contraction finish. When the film of the present invention is used as a heat shrinkable label, the heat shrinkage rate in the direction orthogonal to the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds is preferably 10% or less, and 8% It is more preferable that it is the following, and it is further more preferable that it is 6% or less.
If the heat shrinkage rate in the direction orthogonal to the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds is 10% or less, the dimension itself in the direction orthogonal to the main shrinkage direction after shrinkage is unlikely to be shortened, and shrinkage It is preferable because distortion of a printed pattern or a character to be generated does not easily occur. For example, since it is hard to generate | occur | produce troubles, such as a vertical sinkage which is easy to generate | occur | produce when a to-be-mounted thing is a square shaped bottle etc, it is preferable. The heat shrinkage rate in the direction orthogonal to the main shrinkage direction can also be adjusted in the same manner as the heat shrinkage rate in the main shrinkage direction.

The resin that is the main component of the film of the present invention is not particularly limited, such as polystyrene resins, polyolefin resins, acrylic resins, polyester resins, etc., but polyester resins are preferred from the viewpoint of film sharpness and gloss. It is preferable to use as a main component.

<Polyester resin>
Specific examples of the polyester-based resin used for the film of the present invention include so-called aromatic polyesters and aliphatic polyesters obtained by polycondensation of a dicarboxylic acid component and a diol component.

  Examples of the dicarboxylic acid component constituting the aromatic polyester include terephthalic acid, isophthalic acid, adipic acid, oxalic acid, malonic acid, sebacic acid, phthalic acid, isophthalic acid, sebacic acid, orthophthalic acid, naphthalene dicarboxylic acid, and succinic acid. Azelaic acid, decanoic acid, dimer acid, diphenyletherdicarboxylic acid, cyclohexanedicarboxylic acid, 5-sulfonate isophthalic acid, dodecanedioic acid of long-chain aliphatic dicarboxylic acid, eiconic acid, cyclohexanedicarboxylic acid, trimellitic acid, etc. be able to. Among them, terephthalic acid which is industrially inexpensive and easy to obtain is suitably used, preferably 50 mol% or more, more preferably 55 mol% or more, more preferably 50 mol% or more, based on 100 mol% of the dicarboxylic acid component. Can be used at 60 mol% or more.

As a diol component which comprises aromatic polyester, ethylene glycol, neopentyl glycol, diethylene glycol, 1, 4- cyclohexane dimethanol, 1, 4- butanediol, 1, 2- butanediol, 1, 3- butanediol, for example 1,3-propanediol, 1,5-pentanediol, 3-methyl 1,5-pentanediol, 2-methyl-1,3-propanediol, hexanediol, nonanediol, dimerdiol, ethylene oxide of bisphenol A Adducts and propylene oxide adducts, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, 2-butyl-2-ethyl-1,3-propanediol, tricyclodecanedimethanol, 2,2,4-trichloride Chill-1,5-pentanediol, and the like can be given. Two or more of these diol components may be used. Among these diol components, ethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol, 1,3-propanediol and 1,4-butanediol are preferably used in the present invention.

Examples of aliphatic polyesters include aliphatic polyesters obtained by polymerizing hydroxycarboxylic acid, and aliphatic polyesters obtained by polymerizing diol and dicarboxylic acid.
Examples of aliphatic polyesters obtained by polymerizing hydroxycarboxylic acids include polylactic acid, polycaprolactone, poly (3-hydroxybutyrate), poly (4-hydroxybutyrate) and poly (3-hydroxypropionate). Etc. They may also be copolymers with other copolymerizable monomers.
Examples of aliphatic polyesters obtained by polymerizing diols and dicarboxylic acids include polyethylene succinate, polybutylene succinate, polyethylene adipate, polybutylene adipate, butylene succinate-butylene adipate copolymer, butylene succinate-butylene terephthalate copolymer And coalesced, butylene adipate-butylene terephthalate copolymer, ethylene succinate-ethylene terephthalate copolymer and the like.
Also, copolymers of aliphatic polyesters and aromatic polyesters, so-called aliphatic aromatic polyesters can be used. Examples of aliphatic aromatic polyesters include polybutylene succinate / terephthalate and polybutylene adipate / terephthalate.

In the present invention, the polyester resins may be used alone or in combination of two or more. Particularly preferably used as the polyester-based resin is a polyester-based resin in which the dicarboxylic acid component contains terephthalic acid as the main component and the diol component contains ethylene glycol as the main component. Among them, polyesters comprising (A) a dicarboxylic acid component as a main component of terephthalic acid and a diol component as a main component of ethylene glycol, and further containing any one or more of 1,4-cyclohexanedimethanol, diethylene glycol and neopentyl glycol Resin, or (B) the dicarboxylic acid component is mainly composed of terephthalic acid, and as a diol component ethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol, 1,3-propanediol, 1,4 -A polyester resin containing at least one selected from butanediol and polytetramethylene ether glycol, or a mixture containing (A) and (B) is preferable.
In addition, when the dicarboxylic acid component in all the polyester-type resin components and a diol component are each 100 mol% (total 200 mol%) in the said main component, the thing whose molar ratio is the highest in each component is called a main component. Similarly, the second highest one is referred to as the second component, and may contain the second and subsequent components. The content of the second component is preferably 10 to 45 mol%, more preferably 20 to 40 mol%, based on 100 mol% of all diol components.

The polyester-based resin used in the present invention has an intrinsic viscosity measured at 30 ° C. in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio = 1/1), and the lower limit is 0.4 dl. / G or more is preferable, 0.5 dl / g or more is more preferable, 0.6 dl / g or more is more preferable, and an upper limit thereof is preferably 1.5 dl / g or less, more preferably 1.2 dl / g or less, 1 .0 dl / g is more preferred. If the intrinsic viscosity of the polyester-based resin is in the above range, the mechanical strength of the film of the present invention is also sufficient, and the formability is preferably not deteriorated.

In addition, the film of this invention may contain the additive etc. as needed. Specific examples of the additive include organic lubricants and antiblocking agents such as inorganic lubricants, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants and the like.
In addition, the film of the present invention may contain another thermoplastic resin different from the resin which is the main component of the layer constituting the film of the present invention as long as the effects of the present invention are not impaired. Specifically, polyester elastomers, core-shell type, rubber type modifiers such as graft type or linear random and block copolymers, and the like can be mentioned.

  Specific examples of the antiblocking agent include inorganic particles such as silica, talc and calcium carbonate, inorganic oxides and carbonates, and organic particles such as crosslinked acrylics, crosslinked polyesters, crosslinked polystyrenes and silicones. Be In addition, organic particles having a multi-layered polymerization formed in multiple stages can also be used. Among these, silica and organic particles are preferably used.

  The addition amount of the antiblocking agent is preferably 0.01% by mass or more, more preferably 0.015% by mass or more, and still more preferably 0 based on the mass of the entire resin composition constituting the layer (100% by mass). 0.22 mass% or more, preferably 2 mass% or less, more preferably 1.5 mass% or less, still more preferably 1 mass% or less. If it is more than the above lower limit, slipperiness and blocking resistance can be satisfied, which is preferable. Moreover, if it is below the said upper limit, the disorder | damage | failure of the transparency by surface roughening, the winding shift of the film roll by provision of excessive slipperiness, etc. do not occur, either, and it is preferable.

  The shape of the antiblocking agent is not particularly limited, but a spherical one is preferably used from the viewpoints of aggregation suppression, uniform dispersion, irregular reflection suppression of transmitted light, and irregularities formed on the film surface. The average particle diameter of the antiblocking agent is preferably 0.1 μm or more, more preferably 1 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, and still more preferably 6 μm or less. If the average particle diameter of the antiblocking agent is equal to or more than the above lower limit, it is possible to provide asperities sufficient to express slipperiness and blocking resistance. Moreover, if it is below the said upper limit and printing is performed on a film and a designability is improved etc., an ink omission etc. do not arise and it is preferable, without impairing the external appearance of a printing pattern. The particle size distribution of the antiblocking agent is not particularly limited, but in general, those having a narrow particle size distribution are preferably used. When the particle size distribution is wide, it may be included that deviates from the range of the preferred particle size described above.

Furthermore, the film of the present invention may be coated with various coatings such as in-line coating, off-line coating, and the like to the extent that the effects of the present invention are not impaired to further impart functionalization. Examples of functionalization include easy adhesion, UV cutability, oxygen barrier property, scratch resistance, slipperiness, heat resistance, antistatic property, and solvent resistance. By applying various coatings, it is also possible to obtain a heat-shrinkable film having a combination of light-shielding properties, aesthetics, sharpness, glossiness and various functions.

<Method of Producing Film of the Present Invention>
The film of the present invention can be produced by known methods. The form of the film may be either planar or tubular, but is preferably planar from the viewpoint of productivity (can be taken as a product in the width direction of the film) and printing on the inner surface. As a method of producing a flat film, for example, a plurality of raw materials are measured and mixed, a resin is melted using one or more extruders, extruded from a T die, and cooled and solidified by chilled rolls, longitudinal The film may be obtained by roll stretching in the direction, tenter stretching in the lateral direction, annealing, cooling, and winding with a winder.
There is no particular limitation on the order of longitudinal stretching and transverse stretching, and the number of times, and longitudinal stretching / transverse stretching, longitudinal stretch / transverse stretch / longitudinal stretch, transverse stretch / longitudinal stretch, longitudinal stretch / transverse stretch / transverse stretch, etc. A combination of By appropriately adjusting the stretching direction and the stretching ratio, the main stretching direction is taken as the transverse direction, and the main shrinking direction is a film in the transverse direction, or the main stretching direction is taken as the longitudinal direction, and the main shrinkage direction is any film in the longitudinal direction. Methods, films can also be selected.
Moreover, the method of cutting open the film manufactured by the tubular method and making it planar can also be applied.
The extrusion conditions need to be adjusted according to the resin used, and it is also possible to control the dispersion state of various raw materials including the colorant by optimizing the extrusion temperature and the shear state, and desired various properties of the film. It is effective to make it a value.

The stretching ratio is preferably 2 to 10 times in the longitudinal direction, 2 to 10 times in the transverse direction, more preferably 3 to 6 times in the longitudinal direction, and in the transverse direction in applications such as for overlap and contraction in two directions. It is about 3 to 6 times. On the other hand, for heat-shrinkable labels, etc., in applications that are mainly contracted in one direction, the direction corresponding to the main contraction direction is preferably 2 to 10 times, more preferably 3 to 8 times, preferably perpendicular to it. It is desirable to select a magnification ratio that is in the range of 1 to 2 times, more preferably 1.01 to 1.5 times and substantially uniaxial stretching. In addition, 1 time points out the case where it does not extend.
The stretched film stretched at a stretching ratio within the range of the uniaxial stretching does not become too large in the thermal contraction rate in the direction orthogonal to the main shrinkage direction. For example, when used as a thermal contraction label, it is attached to a container When doing so, the film shrinks thermally also in the height direction of the container, which is preferable because it can suppress the so-called vertical shrinkage phenomenon.

  In the method for producing a film of the present invention, the film is preferably stretched four times or more in the transverse direction as a direction corresponding to the main shrinkage direction. If it is stretched by 4 times or more, the shrinkage rate can be sufficiently imparted, and of course as a label covering the main part of the target container, and also when used as a full shrink label covering the entire target container, shrinkage unevenness It does not occur and wrinkles are preferable. In addition to the above respective stretching steps, a stretching step can be further added.

  The stretching temperature can be appropriately selected depending on the glass transition temperature (Tg) of the resin used and the characteristics required for the heat shrinkable film, but it is adjusted in the range of Tg to (Tg + 20) ° C, preferably Tg to (Tg + 10 ° C) . If the stretching temperature is at least Tg, problems such as breakage of the film during stretching and whitening of the film can be suppressed, which is preferable. If the stretching temperature is (Tg + 20) ° C or less, the shrinkage ratio is reduced, and problems such as difficulty in covering the entire target container do not occur, and uniform stretching is also possible, which is preferable.

In the method for producing a film of the present invention, heat treatment can be performed for the purpose of reducing the natural shrinkage rate, improving the heat shrinkage characteristics, and the like. The heat treatment temperature can be (stretching temperature −40 ° C.) to (stretching temperature + 30 ° C.), preferably (stretching temperature −30 ° C.) to (stretching temperature + 20 ° C.). If the heat treatment temperature is (stretching temperature-40 ° C) or more, a sufficient heat treatment effect can be obtained, which is preferable. Moreover, if it is (stretching temperature +30 degreeC) or less, a required contraction rate can be obtained and it is preferable. The heat treatment time is 0 to 120 seconds, preferably 0 to 60 seconds, more preferably 0 to 30 seconds, and still more preferably 0 to 15 seconds. If the heat treatment time is 120 seconds or less, it is possible to suppress the decrease in the shrinkage rate and to suppress the decrease in the productivity. The heat treatment can be performed using a known heat treatment machine such as a roll or a tenter. By performing heat treatment without quenching the stretched film, it is possible to prevent rapid contraction at the time of heat shrinkage.

The film of the present invention may be coated on one side or both sides of the film prior to drawing, during the drawing process, or after drawing to provide further functionalization. Examples of functionalization include easy adhesion, UV cutability, oxygen barrier property, scratch resistance, slipperiness, heat resistance, antistatic property, and solvent resistance.
In addition, the film of the present invention may be subjected to surface treatment or surface treatment such as antistatic treatment, corona treatment, printing, coating, vapor deposition, and the like, as well as bag-making processing and perforation processing by various solvents and heat sealing. It can be applied.

<Molded Article of the Present Invention, Heat-Shrinkable Label of the Present Invention, and Container of the Present Invention>
The film of the present invention is excellent in light-shielding performance and is also excellent in sharpness, glossiness, and finished appearance after shrinkage, so its use is not particularly limited, but a printed layer, if necessary, By forming a vapor deposition layer or other functional layer, it can be used as a base of various molded articles such as bottles (blow bottles) of various resins, trays, lunch boxes, sugar beet containers, dairy containers and the like. And the molded article of this invention obtained can be used as a container etc. In addition, the film of the present invention can be used as a base material of heat-shrinkable labels for food containers (for example, PET bottles for soft drinks or food, glass bottles, preferably PET bottles). The heat-shrinkable label of the present invention is excellent in light-shielding performance, excellent in sharpness and glossiness, and excellent in shrinkage characteristics, so that it has a complicated shape (for example, a cylinder whose center is constricted, square prism with corners, pentagonal prism Even if it is a hexagonal column or the like, it can be closely attached to the shape, and it becomes a beautifully attached label free from wrinkles and avatars. And the container of this invention which used the label can be used as a container for various uses.

In addition, when using the film of this invention as a heat-shrinkable label for containers, such as a PET bottle and a glass bottle, it is preferable to use it as a full shrink label which covers from the bottom part periphery of a container to the cap part top especially. By using the full shrink label, the light shielding performance of the container is enhanced, and the entire container can be packaged with a uniform design, and an excellent appearance can be obtained.

EXAMPLES Hereinafter, the present invention will be described by way of examples, but the scope of the present invention is not limited by these examples.

(1) Shrinkage Ratio The shrinkage ratio of the film in the main shrinkage direction and in the orthogonal direction was measured by the following method. A sample cut out to a size of 120 mm in the measurement direction of shrinkage and 10 mm in the direction perpendicular to the measurement direction is prepared, marked with 100 mm intervals in the measurement direction, and immersed in warm water at 80 ° C. for 10 seconds The shrinkage ratio was used according to the following equation.
Shrinkage rate = {(100-L) / 100} x 100 (%)
L (unit mm) is the mark line interval after contraction

(2) Light transmittance Using a near infrared, ultraviolet, visible spectrophotometer (trade name "U-3900H" manufactured by Hitachi High-Technologies Corporation), the light transmittance in the wavelength range of 200 to 800 nm is measured, and the following It evaluated by the standard.
◎: 80% or more of the wavelength range where the light transmittance is 5% or less at 200-500 nm ○: 50% or more of the wavelength range where the light transmittance is 5% or less at 200-500 nm x: light transmission at 200-500 nm Less than 50% in the wavelength range where the rate is 5% or less

(3) Light reflectance The light reflectance in the wavelength range of 200 to 800 nm was measured using a near infrared, ultraviolet, visible spectrophotometer (trade name "U-3900H" manufactured by Hitachi High-Technologies Corporation), and the following It evaluated by the standard.
:: no wavelength range of light reflectance over 30% at 200 to 500 nm x: wavelength range of light reflectance over 30% at 200 to 500 nm

(4) Glossiness According to JIS K7105, the glossiness was measured and evaluated based on the following criteria.
○: 90% or more ×: less than 90%

(5) Surface roughness Surface roughness measuring device (electron beam three-dimensional roughness analyzer: manufactured by Elionix Co., Ltd., surface shape analysis software: manufactured by Ryoka System Co., Ltd. "VertScan 2.0"), magnification ratio The surface roughness was measured at 50 times, and the surface roughness Sa was evaluated based on the following criteria.
○: 60 nm or less ×: over 60 nm

(6) The shrink finish film is cut out at 205 mm in the main shrinkage direction when using the following 350 ml bottle, and 235 mm in the main shrinkage direction when using the following 500 ml bottle so that it overlaps by 10 mm in the main shrinkage direction. The folded part is heat sealed to make it cylindrical. Then, this cylindrical film was placed on the following 350 ml and 500 ml polyhedral bottles to the bottom of the bottle to prepare a sample for evaluation of shrinkage finish. The sample for evaluation was passed through the temperature of each zone in the tunnel for 5 seconds under the following temperature conditions without rotating in the contraction tunnel of 3 m in length (3 zones configuration) in the vapor heating system, and the film was shrunk into the bottle Wrinkles and unevenness were not observed, and contraction was checked to confirm that it was not insufficient. Evaluation was performed with each sample N = 10. The temperature conditions in the shrinker were set as follows.
Temperature condition:
1 zone / 80-85 ° C, 2 zone / 85-95 ° C, 3 zone / 95-100 ° C
Nozzle position in the tunnel to inject steam:
1 zone / film lower, 2 zones first / film center, 2 zones second / whole film, 3 zones / whole film temperature control:
The amount of steam is adjusted by opening and closing the valve of the steam piping leading to the nozzle.
The length in the direction orthogonal to the main shrinkage direction of the film (the height direction of the PET bottle) is appropriately adjusted depending on the shape of the bottle when covering the top of the cap of the PET bottle and covering the entire barrel of the PET bottle did.
PET bottle used:
For 350 ml (height 208 mm, body diameter 60 mm, bore 26 mm)
For 500 ml (height 200 mm, body diameter 66 mm, bore 26.5 mm)
Evaluation criteria:
:: Capable to cover the upper portion of the cap of the PET bottle, no wrinkles, unevenness, insufficient shrinkage ○: able to cover the entire barrel of the PET bottle, no wrinkles, unevenness, insufficient shrinkage △: insufficient shrinkage at the barrel of the PET bottle There are either wrinkles or unevenness

(7) Using a color difference colorimeter (manufactured by Suga Test Instruments Co., Ltd., model “SC-T”), L * value, a * value and b * value were measured according to JIS Z8729 in a transmission method.

The raw materials used for each example and comparative example are as follows.
(Polyester resin)
Pes1: A dicarboxylic acid residue is composed of 100% by mole of terephthalic acid residue, a glycol residue is composed of 65% by mole of ethylene glycol residue, 3% by mole of diethylene glycol residue, and 32% by mole of 1,4-cyclohexanedimethanol residue Copolymerized polyester Pes2: Copolymerized polyester Pes3 composed of 90 mol% of terephthalic acid residue, 10 mol% of isophthalic acid residue and 100 mol% of 1,4-butanediol residue of glycol residue: Copolymerized polyester (coloring agent) in which the dicarboxylic acid group is composed of 70% by mole of terephthalic acid residue, 30% by mole of isophthalic acid residue, and 100% by mole of ethylene glycol residue
Red masterbatch: 10-15% of CI Pigment Red 177 is contained with respect to Pes 1 described above.
Blue master batch: containing 1 to 5% of CI Pigment Blue 15: 3 based on Pes1.
Green masterbatch: containing 1 to 5% of CI Pigment Green 7, less than 1% of carbon black, and 5 to 15% of an azo-nickel complex pigment with respect to Pes 1 described above.
Brown masterbatch: containing 5 to 10% of CI Pigment Red 101, less than 1% of carbon black, and 1 to 5% of an azo-nickel complexed pigment relative to Pes 1 described above.
White master batch: Contains 60% titanium oxide relative to Pes 1 in the previous period.
(Others)
Silica master batch 1: 90% by mass of the above Pes 1 and 10% by mass of spherical silica (average particle diameter 3.0 μm) are contained.

Example 1
What mixed 25 mass% of brown masterbatches, 60 mass% of Pes 1, 14 mass% of Pes 2, and 1 mass% of silica master batch as a coloring agent was used as a central layer composition A1.
What dry-blended the ratio of 85 mass% of Pes 1 and 14 mass% of Pes 2 in the ratio of 1 mass% of a silica masterbatch was made into front and back layer composition B1.
The central layer composition A1 and the front and back layer composition B1 are extruded by separate extruders, and the film thickness ratio after stretching is obtained using a T-die for multilayer molding so that B / A / B = 1/7/1 270 After laminating in the molten state of ° C, the die temperature is 270 ° C, the die width is 240 mm, and it is extruded from a T die that makes a lip gap 1 mm, and casting is performed at a setting of casting temperature 65 ° C. A sheet of width = 220 mm, average thickness = 200 μm Obtained.
Next, the end of the obtained raw sheet is held by a tenter clip, and stretching is performed in a tenter oven at a stretching temperature of 83 ° C. and a stretching ratio of 6 times in the lateral direction. L * value = 35, a * value A laminated film having an average thickness of 39 μm in which 10 and b * value = 50 was obtained. It evaluated about this. The results are shown in Table 1.

(Example 2)
The central layer composition A1 is changed to 35% by mass of Pes1, 15% by mass of Pes2, and 25% by mass of Pes3; 60% by mass of Pes1, 60% by mass of Pes1, 15% by mass of Pes2; A laminated film having an average thickness of 40 μm was obtained in the same manner as in Example 1 except that the content was changed to% by mass, L * value = 30, a * value = 11, b * value = 43. It evaluated about this. The results are shown in Table 1.

(Comparative example 9)
L * value = 52, a * value =-as in Example 1 except that the coloring agent was changed to green and the film thickness ratio was changed to front / back layer / intermediate layer / front / back layer = 1/6/1. 30, a laminated film with an average thickness of 41 μm, in which b * value = 63, was obtained. It evaluated about this. The results are shown in Table 1.

(Comparative example 10)
L * value = 54, a * value =-as in Example 2 except that the coloring agent was changed to green and the film thickness ratio was changed to front / back layer / intermediate layer / front / back layer = 1/6/1. A laminated film having an average thickness of 40 μm, which gives a value of 29, and b * value = 62, was obtained. It evaluated about this. The results are shown in Table 1.

(Comparative example 11)
The coloring agent of the central layer composition A1 is changed to red, the addition amount of the masterbatch is changed to 15% by mass, the Pes 1 is changed to 70% by mass, and the film thickness ratio is front layer / center layer / front layer 1 A laminated film with an average thickness of 40 μm was obtained in which L * value = 19, a * value = 34, and b * value = 11, as in Example 1 except that the ratio was changed to / 6/1. It evaluated about this. The results are shown in Table 1.

(Comparative example 7)
A laminated film having an average thickness of 41 μm is obtained in the same manner as in Example 5 except that the coloring agent of the central layer composition is changed to blue: L * value = 25, a * value = 7, b * value = −30. The It evaluated about this. The results are shown in Table 1.

(Example 7)
The average of L * value = 50, a * value = 8, b * value = 60 as in Example 1 except that the film thickness ratio is set as front / back layer / center layer / front / back layer = 1/2/1. A laminated film with a thickness of 39 μm was obtained. It evaluated about this. The results are shown in Table 1.

(Example 8)
A laminated film having an average thickness of 40 μm in which L * value = 29, a * value = 20, b * value = 38 was obtained as in Example 1 except that the film thickness ratio was changed to 1/10. It evaluated about this. The results are shown in Table 1.

(Example 9)
A laminated structure with an average thickness of 39 μm in which L * value = 34, a * value = 10, b * value = 49 as in Example 1 except that the shrinkage factor in the main shrinkage direction of the film is adjusted to 25%. I got a film. It evaluated about this. The results are shown in Table 2.

(Comparative example 8)
A laminated structure having an average thickness of 39 μm in which L * value = 34, a * value = 11, b * value = 50 as in Example 1 except that the shrinkage rate in the main shrinkage direction of the film is adjusted to 18%. I got a film. It evaluated about this. The results are shown in Table 2.

(Comparative example 1)
15% by mass of a red masterbatch as a colorant, 70% by mass of Pes, 14% by mass of Pes 2 and 1% by mass of a silica masterbatch, and the same direction set at a setting temperature of 250 ° C. to 260 ° C. A twin-screw extruder (made by Toshiba Machine Co., Ltd., bore size = 25 mmφ, L / D = 40) is melted and kneaded, die temperature is 260 ° C, die width is 300 mm, lip gap is 1 mm, and it is extruded from T die. Casting was performed at a setting of 60 ° C. to obtain a sheet of width = 280 mm and average thickness = 200 μm.
Next, the end of the obtained raw sheet is held by a tenter clip, and stretching is performed in a tenter oven at a stretching temperature of 83 ° C. and a stretching ratio of 6 times in the lateral direction, L * value = 3, a * value A single-layer film with a thickness average of 39 μm was obtained, of which = 14 and b * value = 8. It evaluated about this. The results are shown in Table 2.

(Comparative example 2)
A single-layer film with a thickness average of 39 μm was obtained in which L * value = 6, a * value = 7, and b * value = −21 as in Comparative Example 1 except that the coloring agent was changed to blue. It evaluated about this. The results are shown in Table 2.

(Comparative example 3)
The colorant was not used, and 85% by mass of Pes1, 14% by mass of Pes2 and 1% by mass of the silica masterbatch were blended, and in the same manner as Comparative Example 1, a monolayer film having a thickness of 42 μm was obtained. . It evaluated about this. The results are shown in Table 2.

(Comparative example 4)
A white masterbatch was blended at 35% by mass as the colorant, and a laminated film with an average thickness of 39 μm was obtained in the same manner as in Example 1 except that 50% by mass of Pes 1 was used. It evaluated about this. The results are shown in Table 2.

(Comparative example 5)
The colorant was not used, and 60 wt% of Pes1, 15 wt% of Pes2 and 25 wt% of Pes3 were blended to obtain a monolayer film of 46 μm in average. Printing was performed on this to give a color tone similar to that of Example 4, and a film with L * value = 55, a * value = −33, b * value = 59 was obtained. It evaluated about this. The results are shown in Table 2.

(Comparative example 6)
The colorant was not used, and 60 wt% of Pes1, 15 wt% of Pes2 and 25 wt% of Pes3 were blended to obtain a monolayer film of 51 μm in average. Printing was performed on this to give a color tone similar to that of Example 6, to obtain a film with L * value = 28, a * value = 5, and b * value = −27. It evaluated about this. The results are shown in Table 2.

The films obtained in the examples have excellent light shielding properties, are less roughened on the film surface, are also excellent in the glossiness and the sharpness of the film, and can not be designed with conventional films. Excellent light shielding properties can be achieved at the same time. Also, when attached to a PET bottle, it can be completely covered up to the body portion of the bottle or the upper portion of the cap, and a clean appearance of the appearance can be obtained.

On the other hand, although the films of Comparative Examples 1 and 2 have a light shielding property, the roughness of the film surface is large, the film surface is not glossy, and a film which can satisfy the design can not be obtained. Comparative Example 4 was poor in aesthetics and sharpness, and could not have a combination of label design and light shielding properties. As in the films of Comparative Examples 5 and 6, in the general printing range, a film having a sufficient light-shielding property was not obtained.

The film of the present invention has excellent light shielding performance, is excellent in film appearance such as sharpness and glossiness, and is also excellent in finish after shrinkage, and in particular, alcoholic beverages such as beer, sake and wine, It can be suitably used for, for example, a heat-shrinkable label for beverage packaging in which discoloration or deterioration is likely to occur due to light of a specific wavelength range, such as green tea, vitamin-containing beverages.

Claims (6)

  A heat-shrinkable polyester film having a polyester resin-based layer drawn in at least one direction as a main component on the front and back layers, and at least an ultraviolet absorber-free layer containing a colorant in the intermediate layer It has one layer, and the intermediate layer contains 0.25 to 1.25% of azo-nickel complex pigment and less than 0.25% of carbon black, and the film has a light transmittance of 5 at a wavelength of 200 to 500 nm. Of 90% or more of the wavelength region to be less than 10%, and the light reflectance is 30% or less at wavelengths of 200 to 500 nm, and the surface roughness is 60 nm or less and is immersed in warm water at 80 ° C. for 10 seconds A heat-shrinkable polyester film characterized in that the heat-shrinkage ratio in the main-shrinkage direction is from 20% to 80%.   The polyester-based heat-shrinkable polyester film according to claim 1, wherein the thickness of the layer containing the colorant is 30 to 98% with respect to the total thickness of the film. The heat-shrinkable polyester film according to claim 1, wherein the polyester resin is a mixture containing the following (A) and / or (B).
(A) A polyester-based resin in which the dicarboxylic acid component contains terephthalic acid as the main component, the diol component contains ethylene glycol as the main component, and further contains any one or more of 1,4-cyclohexanedimethanol, diethylene glycol and neopentyl glycol (B) The dicarboxylic acid component contains terephthalic acid as the main component, and as a diol component, ethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol, 1,3-propanediol, 1,4-butanediol, poly Polyester-based resin containing at least one selected from trimethylene glycol   A molded article comprising the heat-shrinkable polyester film according to any one of claims 1 to 3 as a substrate.   A heat-shrinkable label comprising the heat-shrinkable polyester film according to any one of claims 1 to 4 as a substrate.   A container comprising the molded article according to claim 4 or having the heat-shrinkable label according to claim 5 attached thereto.