JP2008302697A - Heat-shrinking polystyrenic resin laminated film roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-shrinking polystyrenic resin laminated film roll which has physical properties being very even over the whole length of a film roll and exhibits a good heat-shrinking property, a good cutting property along perforations, a good anti-blocking property and solvent adhesion strength at the same time and further which can produce a label durable to the storage in a hot warmer. <P>SOLUTION: The film roll of the invention is formed by winding up a polystyrenic resin laminated film formed by laminating a skin layer consisting of a polyester resin on a core layer consisting of a polystyrenic resin. The film roll is provided with a first sample cutting-out part within 2m from a winding end of the film and a final sample cutting-out part within 2m from the start of winding and is adjusted so that a coefficient of variation and a thermal shrinking ratio of the skin layer thickness of all of the samples cut out from respective cutting-out parts are to be within a prescribed range in the case of being provided with the sample cutting-out part for every about 100m from the first sample cutting-out part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat-shrinkable polystyrene resin laminated film roll obtained by winding a heat-shrinkable polystyrene resin laminated film suitable for label applications.

  As a label and cap seal for various containers such as polyethylene terephthalate (PET) containers, polyethylene containers, and glass containers, heat-shrinkable films that shrink by heating are widely used. Such heat-shrinkable film shrinks moderately when it is formed into a label or cap seal (heat-shrinkability), the printed ink is difficult to peel off (solvent adhesive strength), and easily tears along the perforation. Performance (such as perforation cutability) is required, and polyvinyl chloride films, polystyrene films, polyester films, and the like are often used (Patent Document 1).

In addition, since the heat resistance of plastic bottles in recent years has made it possible to heat and store beverages in plastic bottles, bottles equipped with labels can be placed in hot warmers (thermal insulation cases) at convenience stores and the like. It has become. Along with this, there is an increasing demand for heat-shrinkable films that do not deform at high temperatures (about 100 ° C.) (heat resistance) and do not block at high temperatures (blocking resistance). .
JP 7-138388 A

  A heat-shrinkable film made of polyvinyl chloride has a problem that chlorine-based gas is generated when discarded and incinerated. In addition, a heat-shrinkable film made of polystyrene has poor heat resistance and blocking resistance, and therefore cannot withstand boiling treatment at high temperatures and storage in a hot warmer. In addition to this, there is a drawback of poor solvent adhesive strength. On the other hand, a heat-shrinkable film made of polyester is excellent in heat resistance, blocking resistance, and solvent adhesive strength, but it cannot be said that heat-shrinkability and perforation cutability are sufficient, and the desired heat-shrinkability. In addition, in order to develop perforation easy cutability, precise manufacturing condition control technology is required, and there is a problem that it is difficult to manufacture at low cost.

  Therefore, the present inventors have developed good heat shrinkability and perforated cutability of a heat shrinkable film made of polystyrene, while having good blocking resistance and solvent adhesive strength of a heat shrinkable film made of polyester. In order to express the above, a technique for laminating a polyester film layer on the surface layer of a film made of polystyrene was intensively studied.

  However, when the ratio of the skin layer (polyester resin) to the core layer (polystyrene resin) is increased, the transparency of the film deteriorates (haze value) when the film edge cut at the time of production is collected and reused. Will rise). If the end of the film is not collected in order to eliminate such a problem, the manufacturing cost becomes high, and the practicality of the film roll is impaired. Therefore, it is necessary to make the skin layer as thin as possible. However, in the production of a film roll in which such a thin skin layer is laminated on the core layer, if the skin layer is simply laminated on the surface layer of the core layer, it is long. In the film roll, there may be a part where the good heat shrinkability and perforation cutability of polystyrene are impaired, or a part where the good blocking resistance and solvent adhesive strength of the polyester is impaired, Good heat shrinkability, easy perforation cutability, good blocking resistance, and solvent adhesion strength cannot be satisfied simultaneously over the entire length of the film roll.

  The present invention has been achieved as a result of earnest research and development on the production technology of a laminated film roll in which a polystyrene layer and a polyester layer are laminated, and its purpose is extremely uniform in physical properties over the entire length of the film roll. A heat-shrinkable polystyrene resin laminated film roll capable of producing a label that can withstand storage in a hot warmer while simultaneously exhibiting good heat-shrinkability, easy perforation cutability, good blocking resistance, and solvent adhesive strength Is to provide.

Among such the present invention, the constitution of the invention described in claim 1 on at least one side of the core layer mainly composed of polystyrene resin, Ri name by laminating a skin layer mainly composed of polyester resin, between the core layer and the skin layer, a thickness of the heat-shrinkable polystyrene based resin laminated film that has the adhesive layer is provided smaller than the thickness of the skin layer, the length below width 0.2m or 3.0m of Is a heat-shrinkable polystyrene resin laminated film roll wound up to have a thickness of 1000 m or more and 30000 m or less, and the ratio of the thickness of the skin layer to the thickness of the core layer is in the range of 1: 1 to 1: 5 In addition, a first sample cutout portion is provided within 2 m from the end of film winding, and a final cutout portion is provided within 2 m from the start of film winding. When a sample cutout portion is provided for each et about 100 m, it is to satisfy the following requirements (1) and (2).
(1) When the thickness of the skin layer is measured for each sample cut out from each cutout portion, the variation width of the skin layer thickness of all the samples is 20% or less. (2) From each cutout portion When the heat shrinkage rate at 80 ° C. was measured for each cut out sample, the heat shrinkage rate of all the samples was 35% or more and less than 80%.

  The structure of the invention described in claim 2 is the invention described in claim 1, wherein the thickness of the heat-shrinkable polystyrene-based resin laminated film and the heat-shrinkability of each sample cut out from each cut-out portion are as follows. When the thickness of the skin layer constituting the polystyrene resin laminated film was measured, the thickness of the heat-shrinkable polystyrene resin laminated film of all samples was 20 μm or more and 70 μm or less, and the thickness of the skin layer of all samples was 2 μm. The thickness is 10 μm or less.

  The structure of the invention described in claim 3 is the invention described in claim 1, wherein when the haze value is measured for each sample cut out from each cutout portion, the haze values of all the samples are Both are 20 or less.

  The structure of the invention described in claim 4 is that, in the invention described in claim 1, the main component of the core layer is atactic polystyrene or syndiotactic polystyrene.

  The structure of the invention described in claim 5 is the polyethylene according to the invention described in claim 1, wherein the main component of the skin layer is a copolymer of at least one of cyclohexanedimethanol, neopentyl glycol, and isophthalic acid. Being terephthalate.

  The structure of the invention described in Claim 6 exists in the label for bottles manufactured using the heat-shrinkable mixed resin film roll in any one of Claims 1-5.

  The structure of the invention described in claim 7 is that, in the invention described in claim 7, the skin layer mainly composed of a polyester resin is printed with an ink containing an ester solvent. .

  The polystyrene-based resin laminated film roll of the present invention (slit roll before labeling) has a small variation in the thickness of the skin layer, and has a thermal shrinkage rate, perforation cutability, blocking resistance, solvent, over the entire length of the film roll. Since the adhesive strength is good and the fluctuation is small, there are few blocking troubles, and it can be suitably used for producing labels for containers stored in a hot warmer.

  The heat-shrinkable polystyrene-based resin laminated film roll of the present invention cuts out a sample by the following method, and measures the thickness of the skin layer (hereinafter referred to as skin layer thickness) for each of the cut out samples. When the average skin layer thickness, which is an average value of the above, is calculated, the variation rate of the skin layer thickness of all the samples needs to be within a range of ± 20% with respect to the average skin layer thickness.

  In the cutting of the sample in the present invention, first, the first sample cutting portion is provided within 2 m from the end of winding of the film, and the final cutting portion is provided within 2 m from the beginning of winding of the film. A sample cut-out section is provided every about 100 m. Note that “about every 100 m” means that the sample may be cut out at about 100 m ± 1 m.

  The cutting of the sample will be described more specifically. For example, when a polystyrene resin laminated film having a length of 498 m is wound around a roll, the first sample (1 ). For convenience, the sample is cut out in a rectangular shape so as to have a side along the longitudinal direction of the film and a side along the direction orthogonal to the longitudinal direction (not cut diagonally). Subsequently, the second sample (2) is cut away from the cut portion at a distance of 100 m from the winding start side. In the same manner, the third sample (3) is separated to the winding start side of 200 m, the fourth sample (4) is separated to the winding start side of 300 m, and the fifth sample is separated to the winding start side of 400 m. Cut out (5). When the sample is cut out in this way, the remainder becomes shorter than 100 m, so the sixth (final) sample (6) cuts out any portion within 2 m from the start of film winding.

  For each sample cut as described above, the skin layer thickness was measured, and when the average skin layer thickness, which is the average value of the skin layer thicknesses, was calculated, the variation rate of the skin layer thickness of all the samples was The average skin layer thickness needs to be within a range of ± 20%. Here, the variation rate of the skin layer thickness of all the samples is the difference between the maximum and minimum of the skin layer thickness (measured value) of all the samples and the average skin layer thickness within the maximum and minimum. It means the ratio of the difference to the average skin layer thickness when the difference between the larger one and the average skin layer thickness is obtained. As will be described later, the skin layer can be measured using a transmission or reflection electron microscope or the like by slicing the film perpendicular to the surface to form an ultrathin piece.

  In the heat-shrinkable polystyrene resin laminated film roll of the present invention, the variation rate of the skin layer thickness of all cut out samples is preferably within ± 15% of the average skin layer thickness, and within ± 10% It is more preferable to be in the range. In addition, the heat-shrinkable polystyrene-based resin laminated film roll of the present invention is preferably as small as the variation rate of the skin layer thickness of all cut out samples, but the lower limit of the variation rate is about 2% in consideration of measurement accuracy. Is the limit.

  In addition, the heat-shrinkable polystyrene-based resin laminated film roll of the present invention cuts out a sample by the above-described method, and for each cut-out sample, the heat shrinkage rate in the maximum shrinkage direction (that is, the sample is the largest) When the thermal shrinkage rate in the direction of shrinkage is measured, the thermal shrinkage rate of all the samples needs to be 35% or more. By adjusting the heat shrinkage rate to such a range, it is possible to fit the film with a good appearance even when full labeling (labeling the entire container) is performed on a container having a complicated shape.

[Heat shrinkage in maximum shrinkage direction]
A sample cut to 10 cm × 10 cm is immersed in warm water at a temperature of 85 ° C. ± 0.5 ° C. for 10 seconds in a no-load state and thermally contracted, and then is loaded in water at a temperature of 25 ° C. ± 0.5 ° C. Then, the length of the film in the vertical and horizontal directions (and the oblique direction) is measured, and the thermal shrinkage rate in the maximum shrinkage direction is calculated using the following formula 1. The square cut is performed so as to have a side along the longitudinal direction of the film and a side along the direction orthogonal to the longitudinal direction (that is, it is not cut obliquely).
Thermal shrinkage rate = 100 × (length before shrinkage−length after shrinkage) ÷ (length before shrinkage) ・ ・ ・ 1

  When the heat shrinkage rate obtained by the above method is less than 35%, it is not preferable because an appearance defect occurs due to insufficient heat shrinkage of the film when the container is covered and shrunk. In addition, the heat shrinkage rate of the film is preferably 37% or more, and more preferably 40% or more. On the other hand, if the thermal shrinkage rate exceeds 80%, it is not preferable because the frequency of occurrence of large distortion during shrinkage increases.

  Furthermore, the polystyrene-based mixed resin laminated film roll of the present invention is preferably adjusted so that the haze value of all the samples cut out as described above is 20 or less, more preferably 15 or less, and 10 or less. More preferably. A haze value exceeding 20 is not preferable because the appearance deteriorates when the label is formed. Although the haze value is preferably as small as possible, the lower limit of the haze value is considered to be about 1.0 in consideration of measurement accuracy.

  In addition, the polystyrene resin constituting the core layer of the heat-shrinkable polystyrene resin laminated film is not particularly limited as long as the desired heat-shrinkage characteristics can be expressed, and styrene, α-methylstyrene, p-methylstyrene, etc. Homopolymers and copolymers composed of styrene derivatives as well as monomers copolymerizable with styrene and styrene derivatives such as acrylic acid, methacrylic acid, and metal salts thereof (for example, Na, K, Li, Mg, Ca, Metal salts such as Zn and Fe), and copolymers with aliphatic unsaturated carboxylic acids such as acrylic esters and methacrylic esters and derivatives thereof. In addition, various types of polystyrene such as atactic polystyrene, syndiotactic polystyrene, isotactic polystyrene and the like can be used, but when atactic polystyrene is used, the hardness of the resulting heat-shrinkable film becomes appropriate. Therefore, it is preferable.

  On the other hand, by using a polystyrene resin having a syndiotactic structure, it is possible to further improve the mechanical strength and heat resistance. In addition, by using a polystyrene-based resin having a syndiotactic structure, the density of polystyrene is reduced, separation in the recycling process is facilitated, and heat resistance, particularly heat resistance during heat storage, etc. is improved. Further, the change in the printing pitch due to shrinkage with time after film formation is reduced, and it becomes possible to perform high-precision printing as a label. Furthermore, the durability against the solvent contained in the printing ink is improved, and the printability is improved. In addition, the polystyrene resin having a syndiotactic structure has 75% or more of dyads (two constituent units) in the tacticity for quantifying the side chain phenyl group and / or substituted phenyl group by a nuclear magnetic resonance method. Is preferable, and it is more preferable in it being 85% or more. On the other hand, pentad (5 structural units) is preferably 30% or more, and more preferably 50% or more.

  Examples of the polystyrene component constituting the polystyrene resin include polystyrene, poly (p-, m-, or o-methylstyrene), poly (2,4-, 2,5-, 3,4-, or 3, 5-dimethylstyrene), poly (alkylstyrene) such as poly (p-tertiarybutylstyrene), poly (p-, m-, or o-chlorostyrene), poly (p-, m-, or o-bromo) Styrene), poly (p-, m-, or o-fluorostyrene), poly (halogenated styrene), such as poly (o-methyl-p-fluorostyrene), poly (p-, m-, or o-chloro) Poly (halogenated alkyl styrene) such as methyl styrene), poly (p-, m-, or o-methoxy styrene), poly (p-, m-, or o-ethoxy styrene), etc. Poly (alkyl ether styrene) such as poly (carboxyalkyl styrene) poly (p-vinylbenzyl propyl ether) such as poly (p-trimethylsilyl), poly (p-vinylbenzylpropyl ether) such as poly (p-, m-, or o-carboxymethyl styrene) Poly (alkylsilyl styrene) such as styrene) and poly (vinyl benzyl dimethoxy phosphide). In addition, it is also possible to mix | blend a plasticizer, a compatibilizing agent, etc. with a polystyrene-type resin in order to lower | hang a heat shrink start temperature, or to improve impact resistance.

  Further, it is preferable to add a thermoplastic resin and / or a rubber component to the polystyrene resin. Examples of the thermoplastic resin include polystyrene resins having an atactic structure, such as polystyrene resins, AS resins, and ABS resins, polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, nylon 6, nylon 66, nylon 12, and nylon 4. And polyamide resins such as polyhexamethylene adipamide, and polyolefin resins such as polyethylene, polypropylene, and polybutene. On the other hand, the rubber component is preferably a rubbery copolymer containing a styrene compound as a constituent component, and examples thereof include random, block or graft copolymers obtained by copolymerizing at least one of styrene and a rubber component. be able to. Examples of such a rubbery copolymer include styrene-butadiene copolymer rubber, styrene-isoprene block copolymer, rubber obtained by hydrogenating part or all of the butadiene portion, and methyl acrylate-butadiene-styrene. Examples thereof include copolymer rubber, acrylonitrile-butadiene-styrene copolymer rubber, acrylonitrile-alkyl acrylate-butadiene-styrene copolymer rubber, and methyl methacrylate-alkyl acrylate-butadiene-styrene copolymer rubber. The rubbery copolymer containing the above-mentioned styrene compound as a constituent component has a styrene unit, and therefore has good dispersibility with respect to a polystyrene resin having a syndiotactic structure, and has an effect of improving plasticity with respect to the polystyrene resin. large. Moreover, as a compatibility regulator, the rubber-like copolymer which contains the above-mentioned styrene-type compound as the structural component can be used conveniently.

  On the other hand, other rubber components include natural rubber, polybutadiene, polyisoprene, polyisobutylene, neoprene, ethylene-propylene copolymer rubber, urethane rubber, silicone rubber, acrylic rubber, polyether-ester rubber, polyester-ester rubber. Etc. can be used.

  Further, the weight-average molecular weight of the polystyrene resin is preferably 10,000 or more, and more preferably 50,000 or more. A film having a weight average molecular weight of less than 10,000 is not preferable because the strength and heat resistance of the film are liable to decrease. The upper limit of the weight average molecular weight is not particularly limited, but if the weight average molecular weight exceeds 1,500,000, it may be unfavorable because breakage may occur due to an increase in stretching tension.

  On the other hand, as the polyester resin constituting the skin layer, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polypentamethylene terephthalate, polyhexamethylene terephthalate, polyethylene-2, Crystalline polyesters such as 6-naphthalate (PEN) can be used. Moreover, it is also possible to use what copolymerized the acid component and / or glycol component of 10 mol% or less in 100 mol% based on these.

  That is, as the polyester resin, a resin composed of a dicarboxylic acid component and a polyhydric alcohol component can be used. More specifically, a first dicarboxylic acid component (for example, a terephthalic acid component) that constitutes a base unit (for example, a crystalline unit such as polyethylene terephthalate) and a first polyhydric alcohol component (for example, an ethylene glycol component) And the like, and a resin containing a second dicarboxylic acid component different from the first dicarboxylic acid component and / or a second polyhydric alcohol component different from the first polyhydric alcohol component can be used. . Whether the film has crystallinity or thermal properties (thermal shrinkage, glass transition temperature, crystallization temperature, melting) by the second dicarboxylic acid component and / or the second polyhydric alcohol component (preferably the second alcohol component) Temperature).

  In addition, as dicarboxylic acids forming the dicarboxylic acid component (first dicarboxylic acid component, second dicarboxylic acid component), for example, an aromatic dicarboxylic acid, an ester-forming derivative thereof, an aliphatic dicarboxylic acid, or the like can be used. it can. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid, 5-sodium sulfoisophthalic acid, and the like. In addition, examples of ester derivatives include derivatives such as dialkyl esters and diaryl esters. Examples of the aliphatic dicarboxylic acid include dimer acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, oxalic acid, and succinic acid. Among these dicarboxylic acid components, isophthalic acid component, naphthalene-1,4- or -2,6-dicarboxylic acid component, etc. are useful components for amorphizing the film, and increase the heat shrinkability of the film. be able to.

  In addition to the dicarboxylic acids described above, oxycarboxylic acids such as p-oxybenzoic acid; trivalent or higher carboxylic acids such as trimellitic anhydride and pyromellitic anhydride may be used in combination as necessary.

  The ratio of the second dicarboxylic acid component is, for example, about 3 to 80 mol%, preferably about 5 to 75 mol%, and more preferably about 10 to 70 mol% in 100 mol% of the dicarboxylic acid component.

  On the other hand, the polyhydric alcohol component (first polyhydric alcohol component, second polyhydric alcohol component) may be a diol component or a trihydric or higher alcohol component. Diols forming the diol component include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl- Alkylene glycols such as 1,5-pentanediol, 2-methyl-1,5-pentanediol, 1,9-nonanediol and 1,10-decanediol; cyclic alcohols such as 1,4-cyclohexanedimethanol; diethylene glycol; Ether glycols such as triethylene glycol, polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol, alkylene oxide adducts of bisphenol compounds or derivatives thereof; and dimer diols. Trivalent or higher alcohols include trimethylolpropane, glycerin, pentaerythritol and the like. Among the polyhydric alcohol components described above, a 1,4-cyclohexanedimethanol component, a neopentyl glycol component, and the like are useful components for amorphizing the film, and can improve the heat shrinkability of the film. Moreover, a 1, 4- butanediol component, a propylene glycol component, etc. are components useful for lowering the glass transition temperature of the film and enabling heat shrinkage even at low temperatures.

  The ratio of the second alcohol component is, for example, about 3 to 80 mol%, preferably about 5 to 75 mol%, and more preferably about 10 to 70 mol% in 100 mol% of the polyhydric alcohol component.

  Polyester may be produced by ring-opening polymerization of lactones (such as ε-caprolactone).

  Preferred second dicarboxylic acid component and second alcohol component include amorphous components (isophthalic acid component, naphthalene-1,4- or -2,6-dicarboxylic acid component, 1,4-cyclohexanedimethanol component) , Neopentyl glycol component, etc.). When at least one of these components is contained, an amorphous film can be obtained. When obtaining an amorphous film, the proportion of the amorphous dicarboxylic acid component is, for example, 15 mol% or more, preferably 18 mol% or more, more preferably 20 mol% or more in 100 mol% of the dicarboxylic acid component. The ratio of the amorphous polyhydric alcohol component is, for example, 15 mol% or more, preferably 18 mol% or more, more preferably 20 mol% or more in 100 mol% of the polyhydric alcohol component.

  Furthermore, based on polyethylene terephthalate (PET), dimer acid is copolymerized to 10 mol% or less (PET-D), or polyethylene-2,6-naphthalate (PEN) is copolymerized to 10 mol% or less of isophthalic acid. It is also possible to use what has been done. More preferable examples include PBT, PTT, and PET-D.

  In addition, the heat-shrinkable polystyrene resin laminated film roll of the present invention comprises a plurality of resin layers by melting and extruding raw material polystyrene resin chips and polyester resin chips using a coextrusion method described later. A laminated unstretched laminated sheet (unstretched laminated film) is formed, and the unstretched laminated film (unstretched laminated sheet) is biaxially stretched in the longitudinal direction (longitudinal direction) and the transverse direction (width direction) and then rolled. Manufactured by winding.

  The heat-shrinkable polystyrene-based resin laminated film has a core layer and a skin layer that have A / B (two types and two layers), A / B / A (two types and three layers), or A / B / C (three types and three layers). Layer). From the viewpoint of curl, an A / B / A configuration that is a symmetric layer configuration is preferable. In the description of the heat-shrinkable polystyrene resin laminated film of the present invention, a central layer (that is, A / B / A or A / B /) that is not located on the outermost side among the layers constituting the laminated film. B layer in the case of the C layer structure) and a thick layer in the case of the two-type two-layer structure (that is, the B layer in the case of the A / B layer structure of the thin A layer and the thick B layer) That's it. Further, the outermost layers (that is, the A and B layers in the case of the A / B layer structure, the A and C layers in the case of the A / B / A or A / B / C layer structure), and two A thin layer (that is, an A layer in the case of an A / B layer configuration of a thin A layer and a thick B layer) in the case of the seed two-layer configuration is referred to as a skin layer.

  And the heat-shrinkable polystyrene-type resin laminated film roll of this invention needs to form a core layer with a polystyrene-type resin, and to form a skin layer with a polyester-type resin. In addition, when setting it as the structure of A / B / C (three types and three layers), the polyester-type resin which comprises A layer and the polyester-type resin which comprises C can also be made different. Furthermore, in the resin forming the core layer and skin layer, the purpose is to improve electrostatic adhesion, slipperiness, stretchability, workability, impact resistance, etc., as well as roughening, opacification, hollowing, For the purpose of weight reduction, other resins, plasticizers, compatibility adjusters, inorganic particles, organic particles, colorants, antioxidants, antistatic agents, and the like can be appropriately blended.

  Further, it is necessary to provide an adhesive layer as an intermediate layer between the layers (that is, between the core layer made of polystyrene resin and the skin layer made of polyester resin). As the resin constituting the adhesive layer, olefin-based, ester-based, urethane-based, and acrylic-based copolymers can be suitably used. Among them, styrene-olefin-based copolymers and styrene-acrylic-based copolymers can be used. The use of a copolymer or the like is preferable because the adhesion between the skin layer and the core layer becomes good.

  Moreover, it is necessary to make the thickness of an adhesive bond layer smaller than the thickness of a skin layer, and it is preferable in it being 1-5 micrometers, and it is more preferable in it being 1-3 micrometers.

  On the other hand, in the heat-shrinkable polystyrene resin laminated film, the ratio of the thickness of the skin layer (polyester resin layer) to the core layer (polystyrene resin layer) is in the range of 1: 1 to 1: 5. (I.e., the thickness of the skin layer needs to be 20 to 50% of the whole). In order to effectively reflect both the physical properties of the skin layer and the physical properties of the core layer in the heat-shrinkable polystyrene resin laminated film, the ratio of the thickness of the skin layer to the thickness of the core layer is 1: 2-1. : It is preferable to adjust so that it may become in the range of 4. As described above, by adjusting the ratio of the thickness of the skin layer to the thickness of the core layer within the range of 1: 1 to 1: 5, good heat shrinkability of the polystyrene resin constituting the core layer, the sewing machine It is possible to express the good blocking resistance and solvent adhesive strength of the polyester resin constituting the skin layer while exhibiting easy cutting properties, and the polystyrene resin constituting the core layer is resistant to blocking and solvent. A situation in which an adverse effect is exerted in terms of adhesive strength, or a polyester resin constituting the skin layer is adversely affected in terms of heat shrinkability and perforation easy cutability is avoided.

  In addition, the thickness of the entire heat-shrinkable polystyrene-based resin laminated film is not particularly limited, but is preferably 20 to 70 μm if it is used for producing labels for containers stored in a hot warmer, More preferably, it is 60 μm.

  In addition, when the ratio of the skin layer (polyester resin) to the core layer (polystyrene resin) is increased, the transparency of the film deteriorates (haze value) when the film edge cut at the time of manufacture is recovered and reused. Will rise). If the end of the film is not collected in order to eliminate such problems, the manufacturing cost becomes “BR> b”, which impairs the practicality of the film roll. Therefore, it is necessary to make the skin layer as thin as possible. From this point, the lower limit of the thickness of the skin layer (single layer) is preferably 2 μm or more, more preferably 4 μm or more, and when the skin layer thickness is less than 2 μm, a high temperature of 100 ° C. or more. On the contrary, the upper limit of the thickness of the skin layer is preferably 10 μm or less, more preferably 8 μm or less, and if the thickness of the skin layer exceeds 10 μm, a good sewing machine It is not preferable because easy-cutting properties cannot be obtained.

  And it is preferable to adjust the thickness of a core layer to 60 to 90% of the thickness of the whole film by adjusting the thickness of the whole film and the thickness of a skin layer as mentioned above.

  In order to produce the laminated film as described above, in forming a substantially unoriented resin sheet having a layer structure of A / B, A / B / A, or A / B / C, each layer The resin (polymer) constituting the resin is melted using a separate extruder, co-extruded, cast onto a rotating drum from a die and rapidly cooled and solidified to obtain a substantially unoriented resin sheet (so-called The coextrusion method) can be suitably employed.

  In addition, as a method for stretching an unstretched film, a conventionally used method such as a roll stretching method, a long gap stretching method, a tenter stretching method, or a tubular stretching method can be used. Furthermore, in any of the methods described above, sequential biaxial stretching, simultaneous biaxial stretching, and uniaxial stretching can be appropriately combined. In addition, in biaxial stretching, stretching in the vertical and horizontal directions may be performed simultaneously, but sequential biaxial stretching in which one of them is performed first is effective in terms of production efficiency, and which is the first in the vertical and horizontal stretching order. But it ’s okay. When producing the heat-shrinkable polystyrene-based resin laminated film of the present invention, the draw ratio is preferably 1.0 to 6.0 times, and the magnification in a predetermined direction and the direction orthogonal to the direction. May be the same or different. In the stretching step, it is preferable to perform preheating at a temperature not lower than the glass transition temperature (Tg) of the resin constituting the film and not higher than (Tg + 50) ° C. In heat setting after stretching, it is preferable to pass through a heating zone of 30 ° C. to 150 ° C. for about 1 to 30 seconds after stretching. In addition, if a method of uniaxial stretching in the lateral direction (direction orthogonal to the longitudinal direction of the film) is employed by tenter stretching, it becomes possible to efficiently produce a film having uniform physical properties.

  After the stretching treatment, heat treatment is performed at a predetermined temperature in the range of 60 ° C. to 110 ° C. while stretching 0-15% or relaxing 0-15%, and if necessary, in the range of 40 ° C. to 100 ° C. It is desirable to perform a further heat treatment at a predetermined temperature. It is also possible to preheat the film prior to the stretching process. As the preheating method, for example, a method of heating the film to a temperature of about glass transition temperature (Tg) + 0 ° C. to Tg + 60 ° C. can be employed.

  Further, the width of the film roll is not particularly limited, but from the viewpoint of easy handling, the lower limit of the width of the film roll is preferably 0.35 m or more, and more preferably 0.50 m or more. . On the other hand, the upper limit of the width of the film roll is preferably 2.5 m or less, more preferably 2.0 m or less, and further preferably 1.5 m or less. In addition, the winding length of the film roll is not particularly limited, but the lower limit of the winding length of the film roll is preferably 500 m or more and more preferably 1,000 m or more from the viewpoint of ease of winding and handling. . On the other hand, the upper limit of the roll length of the film roll is preferably 2,5000 m or less, more preferably 20,000 m or less, and further preferably 15,000 m or less. In addition, when a film thickness is about 15 micrometers, it is especially preferable in it being 12000 m or less. In addition, as the winding core, usually, paper of 3 inches, 6 inches, 8 inches, etc., a plastic core or a metal core can be used.

  Further, the film constituting the heat-shrinkable polystyrene-based resin laminated film roll can be subjected to heat treatment or humidity control treatment in order to improve dimensional stability depending on the application. In addition, in order to improve the adhesion of the film surface, corona treatment, coating treatment, flame treatment, etc., and processing such as printing, vapor deposition and the like can be performed.

  Next, the manufacturing method for obtaining the heat-shrinkable polystyrene resin laminated film roll of the present invention will be described in detail. As described above, when the ratio of the skin layer (polyester resin) to the core layer (polystyrene resin) is increased, the transparency of the film deteriorates when the film edge cut at the time of production is recovered and reused ( This causes a problem that the haze value increases). If the end of the film is not collected in order to eliminate such a problem, the manufacturing cost becomes high, and the practicality of the film roll is impaired. Therefore, it is necessary to make the skin layer as thin as possible. On the other hand, it is necessary to form a skin layer having a uniform thickness as much as possible in order not to form a portion that does not exhibit good blocking resistance / solvent adhesive strength of polyester in the film roll.

  Therefore, in order to laminate a uniform thin skin layer on the core layer, the present inventors examined the thickness variation of the skin layer of the film roll. As a result, the thickness variation of the skin layer was mainly melted. It has been found that the resin is greatly affected by various factors in the casting process for converting the resin into an unstretched film. That is, if the temperature adjustment of the melt line from each extruder to the T-die is unstable or the fluctuation of the discharge amount is large, the uneven thickness of the skin layer in the unstretched film becomes large, and the heat shrinkability in the stretched film It has been found that variations in physical properties such as perforation easy cutting properties, blocking resistance, and solvent adhesive strength increase. And in order to laminate the uniform thin skin layer on the core layer, the inventors adjust the fluidity at the time of melting of the resin forming each layer of the skin layer and the core layer, It was found that it is essential to stabilize the extruded state of the resin forming each layer. Furthermore, as a result of examining methods for adjusting the fluidity and stabilizing the extruded state, it is effective to take the following means (1) and (2) when producing a film roll. I found out.

(1) Method for adjusting fluidity during melting of resin forming each layer
As described above, when a chip is melt-extruded to obtain an unstretched film, a resin chip for forming each layer is melted and laminated by each extruder using a co-extrusion method. It is formed into a film by being extruded from a T-die. Usually, in the melt extrusion of polystyrene resin, the extrusion temperature is adjusted to about 190 to 210 ° C. On the other hand, in the melt extrusion of the polyester resin, an extrusion temperature of about 240 to 260 ° C. higher than that of the polystyrene resin is adopted, so that the melt viscosity is lower than that of the polystyrene resin. Adjusted to

  However, with the extrusion temperature of the polyester resin extruder adjusted to 240 to 260 ° C. and the extrusion temperature of the polystyrene resin extruder adjusted to 190 to 210 ° C., these molten resins are laminated in a T-die. When melt extrusion was performed, it was found that the variation of the thickness of the skin layer made of polyester resin would become very large. In addition, if the extrusion temperature of the polyester resin is simply lowered to the extrusion temperature of the polystyrene resin in order to correct such problems, the fluidity of the polyester resin will deteriorate and the variation in the thickness of the skin layer will not be reduced. There was found.

  Therefore, the inventors have intensively studied the extrusion temperature of each resin, the fluidity of each resin, and the variation of the thickness of the skin layer. As a result, in the polyester resin extruder, the temperature of the resin was once adjusted to 240 to 260. After raising the temperature to ℃ and giving a high temperature thermal history, if the temperature is lowered to 190-210 ℃ and then laminated with polystyrene resin in the T-die, the variation in the thickness of the skin layer will be drastically reduced I found. That is, when forming the heat-shrinkable polystyrene resin laminated film of the present invention, in the polyester resin extruder, the temperature of the polyester resin is once increased to 240 to 260 ° C and then decreased to 190 to 210 ° C. If it is made to laminate | stack with polystyrene-type resin after making it change, the fluctuation | variation of the thickness of a skin layer can be made small effectively. The reason why such a phenomenon occurs is not clear, but as described above, in a polyester resin extruder, after giving a high temperature thermal history to the polyester resin, the final extrusion temperature is set to the extrusion temperature of the polystyrene resin. It is considered that by lowering the temperature to a temperature close to, the fluidity of the polyester resin and that of the polystyrene resin are approximated, and the flow of one resin does not disturb the flow of the other resin.

(2) Method for Stabilizing Extrusion State of Resin Forming Each Layer In the production of the polystyrene-based resin laminated film roll of the present invention, as described above, the flowability at the time of melting of the resin forming each layer is adjusted simultaneously. It is preferable to stabilize the temperature of the melt line from each extruder to the T-die and to suppress fluctuations in the discharge amount. In order to stabilize the temperature of the melt line from each extruder to the T die, the temperature control by the ON-OFF method performed in a normal extruder is insufficient, and the PID method (proportional, differential and integral) It is preferable to perform temperature control by an automatic control system).

  On the other hand, it is preferable to interpose a gear pump between the extruder and the T die in order to suppress fluctuations in the discharge amount. In addition, the gear pump normally extrudes the resin while continuously metering by pushing the resin through a gap between two gears as a set, and among them, the so-called two sets of gears are used. It is more preferable to employ a method in which fluctuation of the amount of resin to be measured is reduced by using a parallel type gear pump and slightly shifting the period of the two sets of gears. In addition, the shape of the gear of the gear pump is not particularly limited, but it is preferable to use a helical type gear having grooves provided obliquely because the discharge amount becomes more stable.

  By using the means (1) and (2) described above when forming the unstretched laminated film, it is possible to reduce the thickness fluctuation of the skin layer constituting the laminated film. And, due to that, it is considered that fluctuations in film roll physical properties such as heat shrinkability, perforation easy cutting, blocking resistance, solvent adhesive strength, etc. can be reduced very efficiently. It is done. Further, only one of the above-mentioned means (1) and (2) does not effectively contribute to the reduction of the skin layer thickness variation and physical property variation of the film roll, and (1), (2 ) Is used in combination, it is considered that the variation in physical properties of the film roll can be reduced very efficiently.

  The heat-shrinkable polystyrene resin laminated film roll produced as described above has good physical properties such as heat-shrinkability, perforation cutability, blocking resistance, and solvent adhesive strength, and its fluctuation is very high. Since it is small, it can be widely used for producing labels for various containers and cap seals, and particularly suitable for producing labels for containers stored in a hot warmer.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the embodiments of the examples, and can be appropriately changed without departing from the spirit of the present invention. . Tables 1 to 3 show the properties of the raw material chips A to E used in the examples and comparative examples, and the film roll production conditions in the examples and comparative examples, respectively.

  In Table 1, chip A is polyethylene terephthalate (PET) (Easter 6673 manufactured by Eastman Chemical Co.) containing cyclohexanedimethanol (CHDM), and chip B is a styrene-butyl acrylate copolymer (PS Japan Corporation). SC004), chip C is polystyrene (HH203 manufactured by PS Japan Co., Ltd.), chip D is a styrene-butadiene block copolymer (Denka Clearen 503L manufactured by Denki Kagaku Kogyo Co., Ltd.), and chip E is styrene. -Conjugated diene block copolymer (Tafprene 126 manufactured by Asahi Kasei Chemical Co., Ltd.). In addition, the measuring method of the relative viscosity of above-described raw material chip | tips A-E is as follows.

[Relative viscosity (RV)]
0.25 g of a sample was dissolved in 25 ml of 96% sulfuric acid, 10 ml of this solution was used, the falling seconds were measured at 20 ° C. using an Ostwald viscosity tube, and the relative viscosity was calculated from the following formula 2. In the following formula 2, t (subscript: 0) is the number of seconds for the solvent to fall, and t is the number of seconds for the sample solution to fall.
RV = t / t (subscript: 0) 2

[Example 1]
Using a co-extrusion method, core layer forming resin, skin layer forming resin, and adhesive layer forming resin are melt-extruded from separate extruders (first to third extruders) and dies (T-die). By laminating inside, winding around a rotating metal roll cooled to 40 ° C. by air knife method, and quenching rapidly, the thickness is 250 μm, and three types and five layers configuration, that is, intermediate layers on both sides of the core layer ( Adhesive layers) were laminated, and unstretched films (polystyrene-based resin laminated sheets) having a structure in which skin layers were laminated on the outer sides of the intermediate layers were obtained. The method for forming each layer of the unstretched film (steps until melt extrusion) is as follows. In the following description, the first layer, the second layer, the third layer, the fourth layer, and the fifth layer are referred to in order from the surface layer of the polystyrene-based mixed resin laminated sheet (that is, the surface of the fifth layer is a metal Roll contact surface).

-Formation of the first layer and the fifth layer (skin layer) After the above-mentioned chip A is pre-dried using a blender device, the pre-dried chip A is quantitatively measured in a hopper directly above the first extruder. It was continuously fed with a screw feeder. Then, the supplied chip A was melt-extruded from a T-die by a single-screw first extruder (melt-extruded so as to be laminated on the outer side of the intermediate layer laminated on the outer side of the core layer). In the first extruder, the temperature of the first zone is adjusted to 250 ° C., and the temperature of the second zone is adjusted to 200 ° C. After that, it led to the T die. In order to stabilize the extrusion from the T die, a helical type and parallel type gear pump was interposed between the extruder and the T die. In addition, the extrusion temperature of the first extruder was controlled by the PID control method.

-Formation of the second layer and the fourth layer (adhesive layer) After the above-mentioned chip B is pre-dried using a blender device, the pre-dried chip A is placed in a hopper directly above the second extruder. It supplied continuously with the fixed amount screw feeder. Then, the supplied chip B was melt-extruded from the T die by a single-screw second extruder (melt-extruded so as to be laminated on the outer sides of the core layer). In the second extruder, the temperature of the first zone and the temperature of the second zone were both adjusted to 200 ° C. Similarly to the extrusion by the first extruder, a helical type and parallel type gear pump was interposed between the extruder and the T die in order to stabilize the extrusion from the T die. In addition, the extrusion temperature of the second extruder was also controlled by the PID control method in the same manner as the extrusion temperature of the first extruder.

-Formation of third layer (core layer) Each of the above-mentioned chips C, D, E is preliminarily dried using a blender device, and then these chips C, D, E are fed into a mixing mixer and a quantitative screw feeder. Continuously and separately. The supply amount of chip C was 100% by weight, the supply amount of chip D was 43% by weight, and the supply amount of chip E was 14% by weight. Thereafter, the mixed raw materials of chips C, D, and E mixed in the mixing mixer were continuously and separately supplied to the hopper immediately above the third extruder by a quantitative screw feeder. Then, the supplied chips C, D, and E (mixed ones) were melt-extruded from a T die by a single-screw third extruder. In the second extruder, the temperature of the first zone and the temperature of the second zone were both adjusted to 200 ° C. Also, like the extrusion by the first extruder and the extrusion by the second extruder, in order to stabilize the extrusion from the T die, a helical type and parallel type gear pump was interposed between the extruder and the T die. . In addition, the extrusion temperature of the third extruder was also controlled by the PID control method in the same manner as the extrusion temperatures of the first and second extruders.

  In addition, in the extrusion of resin by each of the above extruders, the discharge amount of the first to third extruders in the formation of the unstretched film is as follows: first layer / second layer / third layer / fourth layer / fifth layer The thickness ratio was adjusted to 6/2/34/2/6. Moreover, also about the extrusion temperature of T-die, temperature control by the PID control system was performed similarly to the 1st-3rd extruder.

  Thereafter, the obtained unstretched film was pre-heated to 110 ° C., stretched at a stretching temperature of 90 ° C. in the transverse direction at a magnification of 4.0 times, then subjected to heat setting treatment at 60 ° C. for 15 seconds, and cooled. By cutting and removing both edges, a biaxially stretched film of about 50 μm was continuously formed over 1000 m to produce a mill roll. When the obtained laminated film after biaxial stretching was sliced thinly in the thickness direction and observed with an electron microscope, the thickness of the first layer, the second layer, the third layer, the fourth layer, the fifth layer was They were about 6 μm, about 2 μm, about 34 μm, about 2 μm, and about 6 μm, respectively.

  In addition, the fluctuation range of the film surface temperature when the film is continuously produced 1000 m is the average temperature ± 0.8 ° C. in the preheating step, the average temperature ± 0.6 ° C. in the stretching step, and the average temperature ± 0.5 ° C. in the heat treatment step It was in the range. Furthermore, the obtained mill roll was slit into a width of 400 mm and a length of 1000 m, and wound around a 3-inch paper tube to obtain a plurality of polystyrene-based mixed resin laminated film rolls (slit rolls). And the characteristic was evaluated by the following method using the obtained slit roll (namely, what was obtained from the same mill roll). In the following skin layer thickness fluctuation rate, heat shrinkage rate in the maximum shrinkage direction, perforation cutability, blocking temperature, and haze measurement, the first sample cut-out portion is within 2 m from the end of film winding. The second to tenth sample cutout portions are provided approximately every 100 m from the first sample cutout portion, and the eleventh sample cutout portion is provided within 2 m from the beginning of winding of the film. A sample film was cut out from each of the sample cutout portions. The evaluation results are shown in Tables 4-6.

[Variation rate of skin layer thickness]
The film cut out from each cut-out section is sliced thinly in the thickness direction and dyed with RuO4 (ruthenium tetroxide), and then each thickness of the first layer and the fifth layer is measured using a transmission electron microscope. It was measured. Then, the maximum / minimum of the skin layer thicknesses of all the samples are obtained, and the difference between the larger of the average skin layer thickness and the average skin layer thickness among the maximum / minimum is calculated, and the difference is calculated. By calculating a ratio (%) with respect to the average skin layer thickness, a variation rate of the skin layer thickness with respect to the average skin layer thickness was obtained.

[Heat shrinkage in maximum shrinkage direction]
The film was cut into a 10 cm × 10 cm square along the longitudinal direction and the orthogonal direction thereof, immersed in warm water at 85 ° C. ± 0.5 ° C. for 10 seconds under no load, and immediately heat-shrinked. After immersing in water at a temperature of ± 0.5 ° C. for 10 seconds, the lengths in the vertical and horizontal directions of the sample were measured, and the thermal contraction rate in the maximum shrinkage direction was calculated according to 3 below. The direction with the largest shrinkage rate was taken as the maximum shrinkage direction.
Thermal shrinkage rate (%) = 100 × (length before shrinkage−length after shrinkage) ÷ (length before shrinkage) 3

[Solvent adhesive strength]
The obtained film roll was slit to a width of 273 mm over the entire length, wound again in a roll shape, and using a tube forming device, 1,3-dioxolane was added to one end of both slit ends of the film. Applied to one side with a width of 2 ± 1 mm so that it does not adhere to the film (coating amount: 3.0 ± 0.3 g / m2). The film was immediately folded and the ends of both slits were overlapped and bonded to form a tube. (Processing speed: 10 m / min). Thereafter, the tube was wound into a roll shape in a flat state. Further, samples were cut from the tube roll at intervals of about 100 m. The first sample cut-out part was the end of the tube winding (0 m from the end of winding), and the final cut-out part was the start of the tube winding (0 m from the start of winding). The tube-shaped sample obtained from each sample cut-out part was cut open so that the adhesion location was in the center, and a film-shaped sample was obtained. Then, a film test piece (n = 10) having a length of 100 mm and a width of 15 mm was cut out from the film sample, and this film test piece was subjected to a tensile tester (made by Baldwin Co., Ltd.) with a distance between chucks of 50 mm. Set "STM-T") so that the solvent adhesion part is located in the center of the chucks, perform a tensile test at a temperature of 23 ° C and a tensile speed of 200 mm / min, and measure the peel strength of the adhesion part. The solvent bond strength was determined by In addition, 10 samples were cut out from each sample cutout part, and the average value of the solvent adhesive strength of 10 samples in each sample cutout part was taken as the solvent adhesive strength of the sample in the cutout part. Moreover, in Table 6, the solvent adhesive strength average value, the maximum value, and the minimum value were shown.

[Perforated easy cutting]
The film cut out from each cutout part was printed in advance with three colors of grass, gold, and white ink from Toyo Ink Manufacturing Co., Ltd. A tube-like label was prepared by adhering both ends to the printed film with 1,3-dioxolane. The label size was a folding diameter of 109 mm and a label length of 90 mm. Thereafter, perforations were made in the above-described label in a direction perpendicular to the main shrinkage direction of the label. In other words, two 1mm thick cardboards are placed under the folded label, and the test sealer (manufactured by Seibu Kikai Co., Ltd.) has a sewing machine blade (1mm pitch blades with a 1mm interval at 100mm length. ), And a sewing machine blade was pressure-bonded to the label at a gauge pressure of 2 kg / cm 2, and a perforation was made parallel to the label end at a position 5 mm from the end of the folded label. In the label, two perforations in which holes having a length of 1 mm were arranged at intervals of 1 mm were provided in parallel over the entire length of the label, and the interval between the two perforations was 10 mm. Then, using a steam tunnel (model: SH-1500-L) manufactured by Fuji Astec Inc., spraying water vapor with a vapor pressure of 1 kg / cm 2 (pressure gauge display: 98 kPa) at a transit time of 2.5 seconds and a zone temperature of 80 ° C. (display). The label was heat-shrinked and attached to a 500 mL PET bottle (round shape, trunk diameter 62 mm, minimum neck diameter 25 mm). At this time, a portion (shoulder portion) having a diameter of about 40 mm was set to one end of the label. After that, this bottle is filled with about 500 mL of water, refrigerated at 5 ° C. for 12 hours, tearing the perforation of the label on the bottle immediately after taking it out of the refrigerator with a fingertip, and tearing it off vertically to remove the label from the bottle The number of completed samples was counted and the ratio (%) to 50 samples was shown.

[Anti-blocking temperature]
Using the film cut out from each cutout part, a label is attached to a plastic bottle (345 ml square bottle) by the same method as the perforation easy cut property described above, and water is poured into the plastic bottle attached with the label. Filled. On the other hand, a metal (iron) piece having a width of about 2 cm, a length of about 2 cm, and a height of about 1 cm was placed on the heat plate, and the temperature of the metal piece was adjusted to 50 ± 1 ° C. Then, the plastic bottle filled with water was turned sideways, and the flat portion was placed on a metal piece and held for 10 seconds. Thereafter, the bottle was immediately lifted, and the state of the label at the contact portion was visually determined according to the following criteria. And the temperature of the heat plate was raised, the said evaluation was repeated every 5 degreeC, and the highest temperature used as (circle) determination was made into blocking resistance temperature.
○: No perforation or distortion in the label ×: Perforation or distortion in the label occurs, or there is discoloration

[Haze]
About the film cut out from each cutout part, based on JISK7136, it measured using the haze meter (Nippon Denshoku Industries Co., Ltd. make, 300A). In addition, the measurement was performed twice and the average value was calculated | required.

[Example 2]
In the formation of the first layer to the fifth layer, the polystyrene pump is the same as in Example 1 except that the gear pump interposed between the extruder and the T die is changed from the helical type and the parallel type to the simple parallel type. A resin laminated film roll was obtained. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 4-6.

[Example 3]
When the unstretched film obtained in the same manner as in Example 1 was stretched in the transverse direction, the same as in Example 1, except that the stretching temperature was about 95 ° C. and the magnification was changed to 5.1 times. A system resin laminated film roll was obtained. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 4-6.

[Comparative Example 1]
In forming the first to fifth layers, a polystyrene-based resin laminated film roll was obtained in the same manner as in Example 1 except that no gear pump was interposed between the extruder and the T die. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 4-6.

[Comparative Example 2]
In the extrusion of the first layer and the third layer, a polystyrene-based resin laminated film roll was obtained in the same manner as in Example 1 except that the temperature of the first zone of the extruder was 200 ° C. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 4-6.

[Comparative Example 3]
When forming an unstretched resin sheet, the same procedure as in Example 1 was performed except that the first layer, the second layer, the fourth layer, and the fifth layer were not formed, and a single-layer structure of only the third layer was formed. A polystyrene resin film roll was obtained. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 4-6. In addition, since the film of Comparative Example 3 was dissolved when 1,3-dioxolane was applied, the anti-blocking temperature was evaluated by using an impulse sealer instead of 1,3-dioxolane.

[Comparative Example 4]
In the formation of the first to fifth layers, a polystyrene-based resin laminated film roll was obtained in the same manner as in Example 1 except that the temperature control in the extruder and the T-die was changed from PID control to ON-OFF control. It was. And the characteristic of the obtained film roll was evaluated by the method similar to Example 1. FIG. The evaluation results are shown in Tables 4-6.

[Effect of film roll of example]
From Tables 4 to 6, the film rolls of the examples all have small variations in skin layer thickness, heat shrinkability, easy perforation cutability, blocking resistance, and solvent adhesive strength, and It can be seen that the fluctuation is small, and it is suitable for producing labels for containers stored in a hot warmer. On the other hand, the film roll of the comparative example has a large heat shrinkage rate and a large variation in the thickness of the skin layer, and thus there is a large variation in the heat shrinkage rate, perforation cutability, blocking resistance, and solvent adhesive strength. In other words, it can be seen that it is not suitable for use in producing labels for containers stored in a hot warmer.

  Since the polystyrene-based resin laminated film roll of the present invention has excellent performance as described above, it can be suitably used for labeling applications for various containers.

Claims (7)

On at least one surface of a core layer mainly composed of polystyrene resin, Ri name by laminating a skin layer mainly composed of polyester resin, between the core layer and the skin layer, than the thickness of the thickness of the skin layer A heat-shrinkable polystyrene-based film obtained by winding a heat-shrinkable polystyrene resin laminated film provided with a small adhesive layer so that the width is 0.2 m or more and 3.0 m or less and the length is 1000 m or more and 30000 m or less. A resin laminated film roll,
The ratio between the thickness of the skin layer and the thickness of the core layer is in the range of 1: 1 to 1: 5,
A first sample cutout is provided within 2 m from the end of film winding, a final cutout is provided within 2 m from the start of film winding, and a sample cutout is provided approximately every 100 m from the first sample cutout. A heat-shrinkable polystyrene resin laminated film roll characterized by satisfying the following requirements (1) and (2).
(1) When the thickness of the skin layer is measured for each sample cut out from each cutout portion, the variation width of the skin layer thickness of all the samples is 20% or less. (2) From each cutout portion When the heat shrinkage rate at 80 ° C. was measured for each cut out sample, the heat shrinkage rate of all the samples was 35% or more and less than 80%. For each sample cut out from each cutout portion, when the thickness of the heat-shrinkable polystyrene resin laminated film and the thickness of the skin layer constituting the heat-shrinkable polystyrene resin laminated film were measured, 2. The heat-shrinkable polystyrene resin according to claim 1, wherein the heat-shrinkable polystyrene resin laminated film has a thickness of 20 μm or more and 70 μm or less, and the skin layers of all the samples have a thickness of 2 μm or more and 10 μm or less. Laminated film roll. 2. The heat-shrinkable mixed resin according to claim 1, wherein the haze value of all the samples is 20 or less when the haze value is measured for each sample cut out from each cut-out portion. Film roll. The heat-shrinkable polystyrene-based resin laminated film roll according to claim 1, wherein the main component of the core layer is atactic polystyrene or syndiotactic polystyrene. 2. The heat-shrinkable polystyrene-based resin laminated film according to claim 1, wherein the main component of the skin layer is polyethylene terephthalate copolymerized with at least one of cyclohexanedimethanol, neopentyl glycol, and isophthalic acid. roll. The label for bottles manufactured using the heat-shrinkable mixed resin film roll in any one of Claims 1-5. The bottle label according to claim 6, wherein the skin layer mainly composed of a polyester resin is printed with an ink containing an ester solvent.