JP2003175546A - Heat-shrinkable polystyrene resin film roll, manufacturing method thereof and heat-shrinkable label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-shrinkable polystyrene resin film roll, a manufacturing method thereof and a heat-shrinkable label which decrease a defect such as a shrinkage fault. <P>SOLUTION: In the heat-shrinkable polystyrene resin film roll, all the degrees of variability of the shrinkage factor of the film in the main direction of shrinkage, in regard to the average value of the shrinkage factor at each measuring place, brought about after the film is immersed in hot water of a temperature 85°C for 10 seconds are within ±5% in the whole of the roll. According to this constitution, the heat-shrinkable film which has the degree of shrinkage large enough practically, which shrinks equally irrespective of fluctuations and unevenness of a temperature in a shrinking process on the occasion of heat shrinkage and causes no nonuniformity of shrinkage and which presents a beautiful external appearance can be obtained. Since nonuniformity of characteristics, such as having a sufficient degree of shrinkage even in a low- temperature heat-shrinking process, is lessened, the film roll which can improve a yield also when it is used for the label can be provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-shrinkable polystyrene resin film roll obtained by winding a heat-shrinkable polystyrene resin film suitable as a packaging material used for covering, binding, and packaging containers and the like, and a roll thereof. The present invention relates to a manufacturing method and a heat shrinkable label.

[0002]

2. Description of the Related Art Since a heat-shrinkable film has a function of shrinkability, it does not use a fixing means such as an adhesive or a fastener,
It can be laminated and integrated with an object by the shrinkage force and shapeability of the film itself. Therefore, it not only has a function of mechanically protecting the object by stacking or coating, but also has a function of binding and sealing. Further, when the heat-shrinkable film itself has a special function, it is possible to add the special function to the object later by laminating. This property is effectively used in the packaging field whose main purpose is to protect the object during storage and distribution and to impart displayability and designability.
For example, various containers such as bottles and cans such as glass and plastic bottles, and long objects such as pipes, rods, wood, various rod-shaped bodies, or sheet-like bodies for covering, binding, and exterior Used as a seal or a seal. Specifically, it is used for the purpose of covering a part or the whole of the cap portion, shoulder portion, and body portion of a bottle for the purpose of displaying, protecting, bundling, and improving the commercial value by functionalization. Furthermore, it is also used for accumulating and packaging a plurality of objects to be packaged, such as boxes, bottles, plates, rods, and notebooks, and for applying a film to the objects to be packaged and packaging with the film (skin package). Used. At this time, when the film is preliminarily displayed and shaped for the purpose of design, it becomes a product called a label.

[0003]

As materials for the heat-shrinkable film, polyvinyl chloride, polystyrene, polyester, polyamide, aliphatic polyolefins and their derivatives, and hydrochloric acid rubber are used. Usually, a film made of these materials is formed into a tube shape, for example, by covering it with a bottle or accumulating pipes and the like, and then heat-shrinking the packaging or binding. However, conventional heat-shrinkable films have poor heat resistance and cannot withstand high-temperature boil treatment or retort treatment, and therefore cannot be sterilized at high temperatures when applied to food, hygiene products, and pharmaceutical applications. There is a drawback that. For example, when the retort treatment is performed, the conventional film has a problem that it is easily damaged during the treatment.

In the case of a conventional heat-shrinkable film, a film made of a polyvinyl chloride resin has a very good heat-shrinkage property, but has a poor adhesion to ink during printing such as a label. Since it is easy to form a gel material of the additive to be added when forming a film, pinholes are easily generated on the printed surface. Furthermore, there is a problem that disposal and incineration are difficult from the environmental point of view. A film made of a polyester resin is excellent in heat resistance, dimensional stability, solvent resistance, etc., but it requires precise control of manufacturing conditions in order to achieve desired heat shrinkage characteristics, adhesiveness, etc. There were problems such as cost.

Further, because of the usefulness of the heat-shrinkable film, the heat-shrinkable film has come to be used also in the field where films and labels which are not heat-shrinkable films have been used conventionally. In particular, many labels for beverage containers have been replaced with a heat-shrinkable label from a sticking label made of paper or a film that is not a heat-shrinkable film. In such cases, special functions are required to protect the container and contents. For example, heat storage, which was conventionally performed only for beverages in glass bottles and metal cans, is now possible even for beverages in plastic bottles due to the improved heat resistance of plastic bottles, and hot storage at convenience stores and station shops. The heat environment of the heat-shrinkable film is diversified because the high-temperature environment experienced after shrink-fitting is diversified, such as the bottle with the label of the heat-shrinkable film being put together with the canned drink in the warm case such as a warmer. Is required to improve. In such a case, the conventional heat-shrinkable film, during or after heat storage of the mounted container,
Label defects due to softening, embrittlement, etc. tend to occur. Especially for hot warmers, in order to bring the temperature of the beverage to about 55 ° C,
The hot plate part on which the container is placed is controlled at about 50 ° C to 75 ° C, but in some cases, the temperature may exceed 120 ° C partially or temporarily within the plate, which may cause defects in the heat shrinkable film. . Furthermore, when the container falls in the hot warmer, the heat-shrinkable film is pressed against the surface of the hot plate, and due to severe temperature and pressure conditions, the film may have large defects or the heat resistance after shrinking and mounting may be high. Problems such as deterioration may occur.

Containers and packages for containing items to be packaged which are prone to deterioration due to light rays, such as beverages such as green tea, juice, beer, etc., foods having synthetic or natural pigments having low light resistance, cosmetics, hygiene products, pharmaceuticals, etc. For things and the like, there is a demand for a function of protecting an object to be packaged from light rays, particularly near-ultraviolet rays which have a great influence. Furthermore, in the field of labels for plastic bottle containers, heat shrinkable labels are widely used in connection with the problem of recycling, and various forms and methods of packaging design are being implemented.

In addition, the low temperature moist heat shrinking process, which is a process used for aseptic filling and packaging which is made possible by a combination of cleaning technology, sterilization technology, packaging speed technology, etc. Since packaging can be completed in a short time at extremely low temperature, heat deterioration of the contents can be prevented, and packaging efficiency can be improved, it is also necessary to develop a heat-shrinkable film that can be used in this low-temperature wet heat shrinkage process. There is. The heat-shrinkable film that can be used in the low temperature wet heat shrinkage process needs to have excellent shrinkability in the low temperature range, and the relatively high shrinkage rate is also advantageous from the viewpoint of shortening the process passage time. Conventionally, a heat-shrinkable polyester-based resin film has been used as a film having such characteristics, but when it is necessary to separately collect bottles and labels, it is difficult to separate the heat-shrinkable polystyrene-based resin that can be separated by specific gravity. Although it was required to use a resin film, the low temperature shrinkage is low, and if the shrinkage temperature is set low, the natural shrinkage before packaging becomes large and the heat resistance after shrinking and mounting decreases. Was likely to occur.

Moreover, since the demand for the heat-shrinkable polystyrene film for special purposes as described above has increased, a homogeneous film roll capable of supplying a film that functions stably with good reproducibility in any part of the roll shape. Production is needed. In the case of a film roll whose quality is not uniform, for example, when the fluctuation of the heat shrinkage in each unit of the label is large, the heating conditions in the tunnel are the same in the heat shrinking step of the label, and therefore the proper heat shrinkage is not shown. Labels will be generated, and these will cause poor shrinkage, shrinkage spots, wrinkles, distortion of patterns, defective appearance due to vertical sinking, etc., making it impossible to make a final product. Usually, the same label for the final product is processed from one film roll, so if the amount of variation in the heat shrinkage rate of the film that constitutes one film roll is large, use the heat shrinking step as described above. Defective rate increases. In particular, this was a serious problem in full-label applications for bottles that covered large areas and required high shrinkage. In addition, since the adhesion stress when mounted in a container changes depending on the site, this may cause poor heat resistance even if a film having excellent heat resistance in a hot warmer is used. further,
When the film has low-temperature shrinkability, that is, when the shrinkage temperature is set low, there arises a problem that natural shrinkage before packaging becomes large, and heat resistance after shrinking and mounting decreases.

The present invention has a sufficiently large heat shrinkage ratio, does not cause uneven shrinkage of the film during heat shrinkage, has a beautiful appearance, and further stabilizes the appearance even when exposed to high temperature conditions after shrinkage. A heat-shrinkable polystyrene-based resin film that holds and is particularly suitable for hot storage such as hot warmers, and even when attached to a container with a complicated shape, extremely high coverage is obtained, and it is necessary to prevent deterioration by light rays. It is possible to stably supply a heat-shrinkable polystyrene-based resin film that is most suitable for packaging articles, and a heat-shrinkable polystyrene-based resin film with a sufficiently high heat-shrinkage rate even in the low-temperature shrinkage process, and A heat-shrinkable polystyrene fiber that can reduce the occurrence of defects such as poor shrinkage, shrinkage spots, wrinkles, distortion, and vertical sink marks in post-processing processes that occur due to changes in the heat shrinkage ratio. And to provide a Muroru and manufacturing method, and heat-shrinkable label thereon.

[0010]

The invention according to claim 1 of the present application is a film roll formed by winding a heat-shrinkable polystyrene resin film, wherein the heat-shrinkable polystyrene resin film is used during the production of the film. In the steady region where the physical properties of the film are stable with respect to the flow direction, the end of the film roll on the winding end side is the start end and the end on the winding start side is the end, and there is one location within 2 m of the start end. A cutout portion is provided, and a cutout portion is provided at intervals of about 100 m from the first cutout portion, and the sample cut out from each cutout portion is heated to a temperature of 85 ° C. for 10 minutes.
When the heat shrinkage after the treatment of dipping for 2 seconds, which is indicated by the rate of change in length in the main shrinkage direction before the treatment, is measured, the heat shrinkage of each sample is ± 5 of the average value of the heat shrinkage of all the samples. It is characterized by being within%.

According to the invention of claim 2 of the present application, in the invention of claim 1, the heat-shrinkable polystyrene-based resin film is cut into a sample having a width of 15 mm and a length of 210 mm, and a sample having a width of 200 mm in the main shrinking direction. Mark the marked lines at intervals, and in the main shrinkage direction of the sample, from 100 ° C to 10 ° C.
The maximum heat shrinkage rate, which is the maximum value of the rate of change in length with respect to the length between the marked lines before the treatment, after the treatment of heating for 1 minute at each temperature up to 150 ° C. at each temperature is 40% or more. Is characterized by.

According to a third aspect of the present invention, in the first aspect of the invention, the heat-shrinkable polystyrene resin film has a label shape of a cylindrical tubular transparent container whose main shrinking direction is a cylindrical cross-sectional direction. The average value T of the transmittance of near-ultraviolet light represented by the following formula 1 when the near-ultraviolet light is applied to a bottle after being heat-shrinked and irradiated from the outside of the container to the inside in a direction perpendicular to the rotational symmetry axis of the container. Is 0.5 or less. T = A / B Formula 1 A: Average value of light energy density (n = 10) transmitted through the film and the container when the heat-shrinkable polystyrene resin film is attached to the transparent container B: Heat-shrinkable polystyrene resin Average value of light energy density (n = 10) transmitted through the transparent container without the resin film attached to the transparent container

According to a fourth aspect of the present invention, in the first aspect of the invention, the heat-shrinkable polystyrene resin film has a width of 5 mm and a length of 100 with the main shrinking direction as the longitudinal direction.
In the middle of the sample cut out to have a size of 50 mm, marked lines are marked at intervals of 50 mm in the longitudinal direction, and a tension of 51.18 gf is applied for 1 minute in an environment of a temperature of 110 ° C. in the main shrinkage direction of the sample. It is characterized in that the rate of change in length with respect to the length between the marked lines after the subsequent treatment is 0% or more and 90% or less.

According to a fifth aspect of the present invention, in the first aspect of the invention, the heat-shrinkable polystyrene-based resin film is cut into a sample having a width of 15 mm and a length of 210 mm, and a sample having a width of 200 mm in the main shrinking direction. Marked lines are marked at intervals, and in the main shrinkage direction of the sample, the heat shrinkage ratio after the treatment of immersing in the hot water temperature of 65 ° C. for 10 seconds is shown by the rate of change in length between the marked lines with respect to that before the treatment. It is characterized by being 5% or more.

According to a sixth aspect of the present invention, in the first aspect of the invention, the heat-shrinkable polystyrene resin film has a stretching mode, a frequency of 50 Hz, and -20 ° C to 250 ° C.
Dispersion other than alpha dispersion is measured in the temperature range where alpha dispersion derived from polystyrene is measured in measurement of dynamic viscoelasticity of film under the temperature range of 2 ° C./min. And

According to a seventh aspect of the present invention, in the first aspect of the invention, the heat-shrinkable polystyrene-based resin film is an unstretched sheet of the heat-shrinkable polystyrene-based resin film before being stretched. Number 50H
z, a temperature range of -20 ° C to 250 ° C, and a temperature range in which the alpha dispersion derived from polystyrene is measured in the measurement of the dynamic viscoelasticity of the film under the condition of the temperature rising rate of 2 ° C / min.
It is characterized in that the unstretched sheet whose dispersion other than alpha dispersion is measured is stretched.

The invention of claim 8 of the present application is, in the invention of claim 1, characterized in that the heat-shrinkable polystyrene resin film has a width of 200 mm or more and a length of 300 m or more.

According to a ninth aspect of the present invention, in the first aspect of the invention, the heat-shrinkable polystyrene-based resin film contains a polystyrene-based resin having a syndiotactic structure.

The invention of claim 10 of the present application is characterized in that, in the invention of claim 1, the heat-shrinkable polystyrene resin film is made of two or more resins having different constitutions.

The invention of claim 11 of the present application comprises, in the invention of claim 10, a step of mixing the resins constituting the heat-shrinkable polystyrene-based resin film and melt-extruding the raw material chips of the respective resins. , Columnar and / or elliptical shape, and the major axis and minor axis of the cross section perpendicular to the longitudinal direction of the raw material chip of the other resin with respect to the raw material chip of the most compounded amount are the average values The method for producing a heat-shrinkable polystyrene film roll according to claim 9, wherein the difference is within ± 50%.

According to a twelfth aspect of the present invention, in the tenth aspect of the invention, the resin constituting the heat-shrinkable polystyrene-based resin film is mixed by using an extruder equipped with a funnel-shaped hopper as a feed portion for the raw material chips. 11. The heat shrinkage according to claim 10, further comprising a step of performing melt extrusion, wherein an inclination angle of the funnel-shaped hypotenuse and a horizontal line segment of the hopper is 65 degrees or more. It is a manufacturing method of a resin film roll.

According to a thirteenth aspect of the present invention, in the first aspect of the invention, the fluctuation range of the surface temperature of the film, which includes a preheating step, a stretching step and a heat treatment step, is measured at any time in each step, The method for producing a heat-shrinkable polystyrene resin film roll according to claim 1, wherein the average temperature is within a range of ± 1 ° C over the entire length of the film.

The invention of claim 14 of the present application is the heat-shrinkable polystyrene resin film obtained from the heat-shrinkable polystyrene resin film roll of claim 1.

The invention of claim 15 of the present application is a heat-shrinkable label comprising the heat-shrinkable polystyrene resin film of claim 14.

The heat-shrinkable polystyrene resin film forming the film roll of the present invention has an end portion on the winding end side of the film roll in a steady region where the physical properties of the film are stable with respect to the flow direction during the production of the film. Is the start end, and the end on the winding start side is the end, and 2m inside the start end
The first cutout is provided within the
A cutout is provided about every 100 m from the cutout, and the temperature of the sample cut out from each cutout is 85 ° C.
After the treatment of immersing in the hot water temperature for 10 seconds, the heat shrinkage rate of each sample was measured when the heat shrinkage rate indicated by the rate of change in length in the main shrinkage direction was measured. Must be within ± 5% of the average value of In the present invention, "heat shrinkage rate" means 10c from the cutout portion.
A sample cut into a square of m × 10 cm is heated to a temperature of 85.
Soak for 10 seconds in hot water at ℃, pull up, then 25 ℃
It is indicated by the rate of change in length after the treatment of immersing in 10 seconds of water and pulling it up. The heat shrinkage rate of each sample is preferably within ± 3% of the average value of the heat shrinkage rates of all the samples, and more preferably within ± 2%.

In the present invention, the heat shrinkage rate is not always
It is not necessary that the heat-shrinkable polystyrene-based resin film forming the film roll is homogenized at a high level as described above over the entire area, and at least, the film physical properties are in the flow direction during the production of the film. In the stable stationary region, it is sufficient that the above-mentioned uniformization is performed at a high level. In addition, in the present invention, the number of the above-mentioned steady regions (regions manufactured in a state of being operated in a steady state) is not limited, and one location per one film roll (in the steady region over the entire film roll) It may exist).

The phrase "the physical properties of the film are stable with respect to the flow direction during the production of the film" means that the physical properties, particularly the heat shrinkage ratio property, are continuously stable. That is, a heat-shrinkable polystyrene-based resin film is produced by molding a molten resin into a film and then subjecting it to stretching or the like. The physical properties of the film change significantly when the stretching conditions are changed. The present invention does not homogenize the heat shrinkage rate of the film obtained when the film forming step and the stretching step are unstable, and stabilizes the film forming step and the stretching step, and when operating in a steady state. In the obtained film, the heat shrinkage is made more uniform than the conventional level. The above steady region is
The total length, preferably 8 of the total length of the film roll
It is good to occupy at least 90%, more preferably at least 90%.

The uniformity of the heat shrinkage ratio in the steady region is such that in the steady region, the end on the winding end side of the film roll is the starting end and the end on the winding start side is the end, and within 2 m of the starting end. The first cutout portion is provided, and the final cutout portion is provided within 2 m inside the terminal end, and further about 100 m from the first cutout portion.
It can be evaluated by providing a cutout portion for each and measuring the heat shrinkage rate of the sample cut out from each cutout portion. In the film roll of the present invention, when the average value of the heat shrinkage rate of all the samples is calculated, the heat shrinkage rate of the sample in each cutout portion is within ± 5% of the above average value. That is, the absolute value of the difference between the heat shrinkage rate HSn (%) of each sample cut out from the cutout portion and the average value HSav (%) of the heat shrinkage rates of all the samples | H
Sn-HSav | is made uniform so as to be 5% or less. In other words, the maximum value HSmax of HSn
(%) And HSav, and HSn minimum value HSm
If the difference between in (%) and HSav is within ± 5%, the above requirement is satisfied.

Since the heat shrinkage rate of each sample is within ± 5% of the average value of the heat shrinkage rate of all the samples, the heat shrinkage rate variation of the entire film roll is also reduced, so that it is produced from one film roll. Fluctuation of the heat shrinkage rate for each label is reduced, and the defect rate in the heat shrinkage step can be drastically reduced. Further, the change of the adhesion stress due to the site when mounted on the container is reduced, and the poor heat resistance in the hot warmer is reduced.

The method of setting the heat shrinkage ratio of each sample within ± 5% of the average value of the heat shrinkage ratios of all the samples is, as will be described later, adjustment of the film production conditions, particularly blending of resins constituting the film. Examples include a method of homogenizing the state, a method of adjusting the fluctuation range of the surface temperature of the film measured at any time in the preheating step, the stretching step, and the heat treatment step.

By setting the heat shrinkage ratio of each sample within ± 5% of the average value of the heat shrinkage ratios of all the samples, the heat shrinkable polystyrene resin film forming the film roll of the present invention has a wide width. It is suitable when the length is 200 mm or more and the length is 300 m or more. Films less than 200 mm wide are
The processability and the handling property are lowered, and the influence such as increase of the defect rate is easily reduced. For the film having a length of less than 300 m, the increase of the defect rate due to the variation of the heat shrinkage rate of the entire film roll is unlikely to occur. However, a film having a width of 200 mm or more and a length of 300 m or more is excellent in processability and handleability from printing to a final product such as a label. Since the influence of increase or the like is great, the increase of the defective rate can be suppressed by setting the variation rate within ± 5%. In particular, it is suitable when the width of the heat-shrinkable polystyrene resin film forming the film roll is 300 mm or more, and further preferably when it is 400 mm or more. Further, it is particularly suitable when the length of the heat-shrinkable polystyrene-based resin film forming the film roll is 400 m or more, and further preferably when it is 500 m or more. Further, from the viewpoint of handleability, the width of the film is 1500 mm or less and the length is 50 mm.
In the case of μm, it is preferably 6,000 m or less.

By setting the heat shrinkage ratio of each sample to within ± 5% of the average value of the heat shrinkage ratio of all samples, the heat shrinkable polystyrene resin film forming the film roll of the present invention is It is suitable when the resin is composed of one or more kinds of resins having different structures. The film is likely to cause an increase in the defective rate due to heat shrinkage variation in the entire film roll,
By setting the fluctuation rate within ± 5%, it is possible to suppress an increase in the defective rate.

The heat-shrinkable polystyrene resin film forming the film roll of the present invention has a width of 15 mm and a length of 2
Marks are drawn at intervals of 200 mm in the main shrinkage direction on the sample cut out to be 10 mm, and heated in the main shrinkage direction of the sample at each temperature from 100 ° C. to every 10 ° C. to 150 ° C. for 1 minute. It is preferable that the maximum thermal contraction rate, which is the maximum value of the rate of change in length after the treatment with respect to the length between the marked lines before the treatment, is 40% or more. Maximum heat shrinkage is 40
When it is less than%, shrinkage is insufficient when used as a label (body label) for a body portion of a bottle that is generally used,
It becomes difficult to make it adhere to the bottle. More preferably, the maximum heat shrinkage is 50% or more. When the maximum heat shrinkage is 50% or more, the shrinkage is not insufficient even for a PET bottle label that requires high shrinkability. The maximum heat shrinkage is more preferably 60% or more, and particularly preferably 70% or more. If the maximum heat shrinkage is in the above range,
Even when used as a label for a container having a complicated shape, insufficient shrinkage is unlikely to occur.

Examples of the method for controlling the maximum heat shrinkage in the above range include, for example, the types and blending ratios of resins constituting the heat shrinkable film, the blending of additives such as plasticizers, the adjustment of the film production conditions, and particularly the high heat shrinking rate. Examples include methods such as increasing the draw ratio, reducing heat setting, and adjusting the compatible state of the constituent components.

The heat-shrinkable polystyrene resin film forming the film roll of the present invention is attached to a bottle as a label shape of a cylindrical tubular transparent container whose main shrinking direction is a cylindrical cross-sectional direction, and after heat shrinking. The average value T of the transmittance of near-ultraviolet rays represented by the following formula 1 when the near-ultraviolet rays are irradiated from the outside of the container to the inside in the direction perpendicular to the rotational symmetry axis of the container is 0.5 or less. preferable. More preferably, the average value T of the transmittance of near ultraviolet rays is 0.2 or less,
It is more preferably 0.1 or less, still more preferably 0.08 or less, and particularly preferably 0.06.
It is the following. When the average value T of the transmittance of near-ultraviolet rays exceeds 0.5, the heat-shrinkable polystyrene resin film of the present invention has a low light-shielding property with respect to an object to be packaged, and it is difficult to prevent deterioration of the object to be packaged by light rays. T = A / B Formula 1 A: Average value of light energy density (n = 10) transmitted through the film and the container when the heat-shrinkable polystyrene resin film is attached to the transparent container B: Heat-shrinkable polystyrene resin Average value of light energy density (n = 10) transmitted through the transparent container without the resin film attached to the transparent container

As a method for obtaining the desired average value T of the transmittance of near-ultraviolet rays, the kind and the compounding ratio of the polystyrene resin constituting the heat-shrinkable film are selected, and the crystallinity and compatibility of the film are adjusted. , Thickness control, light-shielding agent, light absorber,
Compounding of a UV absorber, a selective light absorber, etc. in the film and / or application to the film surface, image formation such as coloring by printing on the film surface, increase in image area, increase in image pattern density, For example, an increase in image density can be mentioned. Further, the average value of the transmittance of near-ultraviolet rays is also increased by the increase of the covering area when the label is attached to the packaged object and the increase of the adhesion strength to the packaged object by adjusting the heat shrinkage property or the heat shrinkage condition of the film. T can be lowered.

The heat-shrinkable polystyrene resin film forming the film roll of the present invention is 50 mm apart in the longitudinal direction in the middle of a sample cut out so that the width is 5 mm and the length is 100 mm with the main shrinking direction as the longitudinal direction. In the main shrinkage direction of the sample, the rate of change in length with respect to the length between the marked lines before the treatment after the treatment of applying a tension of 51.18 gf for 1 minute in an environment of a temperature of 110 ° C. Is 0
% Or more and 90% or less is preferable. More preferably, the rate of change in length is 0% or more and 70% or less, and even more preferably 0% or more and 50% or less. When the length change rate is within the above range, creep is prevented in the most severe heat storage state and the like, and heat resistance is excellent. The smaller the rate of change in length, the less likely creep will occur.

The heat-shrinkable film is exposed to the most severe conditions when it is heat-stored in a hot warmer or the like in a pressure-bonded state after being heat-shrinkable as a label or the like. Therefore, the temperature that is easily received during heating and storage is 110 ° C.
By restricting the degree of creep due to the compressive force that occurs at the same time as the shrinkage behavior under the above environment, the degree of creep due to tension instead of compression can be improved, and heat resistance during heat storage can be improved. The degree of creep is represented by the rate of change in length.

When the heat-shrinkable film is used as a label, the heat shrinkable film is attached to the bottle, heat-shrinked, and then peeled off from the bottle. Width is 5mm and length is 100
In the middle of the sample cut out to have a size of 50 mm, marked lines are marked at intervals of 50 mm in the longitudinal direction, and a tension of 51.18 gf is applied for 1 minute in an environment of a temperature of 110 ° C. in the main shrinkage direction of the sample. It is preferable that the rate of change in length with respect to the length between the marked lines after the subsequent treatment is 0% or more and 90% or less. When a label is formed and mounted on a bottle and heat-shrinked, there is almost no shrinkage in the part opposite to the maximum diameter part of the bottle, so a tension of 51.18 gf is applied in the environment of a temperature of 110 ° C. in the main shrinking direction. If the rate of change in length with respect to the length before the treatment after loading for 1 minute is 0% or more and 90% or less, heat resistance is not a problem, but the rate of length change after heat shrinkage is 0% or more. When it is 90% or less, it is excellent in heat resistance in a more severe heat storage state.

As a method of setting the rate of change in length within the above range, for example, the types and blending ratios of the resins constituting the heat-shrinkable film, particularly the selection of the raw material resin having a high glass transition temperature, and the crystallinity of the film can be selected. Higher, higher compatibility of the resin constituting the film, adjustment of the film production conditions, especially controlling the stretching conditions to leave a large amount of shrinkage stress and contribute to hardness, the temperature elapsed time in the stretching step And a method of controlling the crystallinity of the film and the oriented crystals by controlling the orientation state of the film.

The heat-shrinkable polystyrene resin film forming the film roll of the present invention has a width of 15 mm and a length of 2
In the sample cut out to be 10 mm, marked lines are marked at intervals of 200 mm in the main shrinkage direction, and in the main shrinkage direction of the sample, after the process of dipping in hot water at a temperature of 65 ° C. for 10 seconds, before the process It is preferable that the heat shrinkage ratio indicated by the rate of change in length between the marked lines is 5% or more. More preferably, the heat shrinkage is 10% or more, and further preferably 20% or more. When the heat shrinkage ratio is less than 5%, the low temperature shrinkability is lowered, and it becomes difficult to use it for aseptic filling packaging using the heat shrinkable polystyrene resin film of the present invention.

As a method for obtaining the desired heat shrinkage ratio, the glass transition temperature of the film is lowered by selecting the kind and compounding ratio of the polystyrene resin constituting the heat shrinkable film, and mixing the additive components. Further, a decrease in the stretching temperature corresponding to the glass transition temperature and the like can be mentioned. When the resin composition constituting the film is a completely compatible system, the glass transition temperature becomes a weighted average value of each constituent component, so that the use of additional components is increased in order to lower the glass transition temperature to the shrinking process temperature region. , Heat resistance and dimensional stability tend to decrease. When the resin composition that constitutes the film is an incompatible system, it shrinks near the glass transition temperature of the polystyrene resin, which is the main component, but using a modifier for compatibility adjustment, the dispersed state of the components By adjusting
The glass transition temperature of the film can be lowered to the glass transition temperature of the additive component while maintaining the heat resistance of the polystyrene resin.

The heat-shrinkable polystyrene resin film forming the film roll of the present invention has a stretching mode, a frequency of 50 Hz, a temperature range of -20 ° C to 250 ° C, and a heating rate of 2
In the measurement of the dynamic viscoelasticity of the film under the condition of ° C / min, it is preferable that the dispersion other than the alpha dispersion is measured in the temperature range where the alpha dispersion derived from polystyrene is measured. According to Nakatani, Yamada, et al., Proceedings of the 44th Rheological Symposium (1996) pp. 169-172, a heat-shrinkable polystyrene resin film in which dispersion other than alpha dispersion is measured is alpha dispersion, that is, heat shrinkage. Shrinkage occurs together with relaxation dispersion that causes the phenomenon, and dispersion occurs due to crystallization, generation of gel-like structure, etc. near the end of shrinkage. When dispersion occurs due to crystallization, generation of gel-like structure, etc., heat resistance and dimensional stability after shrinkage are excellent. Dispersions other than alpha dispersion are often found in syndiotactic polystyrene, copolymers thereof, and polystyrene resin compositions having a crystalline component.

The heat-shrinkable polystyrene-based resin film forming the film roll of the present invention is an unstretched sheet of the heat-shrinkable polystyrene-based resin film which has not been stretched yet. 25
In the measurement of the dynamic viscoelasticity of the film under the conditions of the temperature range of 0 ° C. and the heating rate of 2 ° C./min, the dispersion other than the alpha dispersion is measured in the temperature region where the alpha dispersion derived from polystyrene is measured. It can be obtained by stretching an unstretched sheet.

The constitution of the polystyrene resin constituting the heat-shrinkable polystyrene resin film forming the film roll of the present invention is not particularly limited as long as the heat-shrinkable properties described later can be exhibited, but preferably syndiotactic A polystyrene resin containing a polystyrene resin having a tick structure is preferable. More preferably, a polystyrene resin having a syndiotactic structure is used as the polystyrene resin. By using a polystyrene resin having a syndiotactic structure, mechanical strength and heat resistance are improved. By using such a polystyrene-based resin, the density of polystyrene is low, and in addition to being advantageous for separation in the recycling step, it is excellent in heat resistance, particularly heat resistance during heat storage, and after the film formation, Changes in the printing pitch due to contraction are reduced, and high-precision printing can be performed as a label. Further, the durability against the solvent contained in the printing ink is also improved, and the printability is excellent.

The polystyrene resin having the syndiotactic structure is preferably a diad (two constitutional units) in the tacticity of quantifying the side chain phenyl group and / or substituted phenyl group by a nuclear magnetic resonance method. It is preferably 75% or more, more preferably 85% or more, and is preferably 30% or more, more preferably 50% or more in pentad (5 structural units).

The polystyrene component constituting the polystyrene resin used in the present invention includes polystyrene, poly (p-, m-, or o-methylstyrene), poly (2,4-, 2,5-, 3, 4- or 3,5-dimethylstyrene), poly (p-tertiarybutylstyrene), and other poly (alkylstyrene), poly (p-, m)
-Or o-chlorostyrene), poly (p-, m-,
Or poly (halogenated styrene) such as o-bromostyrene), poly (p-, m-, or o-fluorostyrene), poly (o-methyl-p-fluorostyrene), poly (p-, m-, Or poly (halogenated substituted alkylstyrene) such as o-chloromethylstyrene), poly (p
-, M-, or o-methoxystyrene), poly (p
-(M-, or o-ethoxystyrene) or other poly (alkoxystyrene), poly (p-, m-, or o-carboxymethylstyrene) or other poly (carboxyalkylstyrene) poly (p-vinylbenzylpropyl ether) ) Etc., poly (alkyl ether styrene), poly (p
-Trimethylsilylstyrene) and other poly (alkylsilylstyrenes), as well as poly (vinylbenzyldimethoxyphosphide) and the like.

The heat-shrinkable polystyrene-based resin film used in the present invention is a polystyrene-based resin constituting at least one layer of the film, which is plasticized for the purpose of lowering the heat shrinkage initiation temperature and improving impact resistance. It is preferable that the agent, the compatibilizer and the like are added during the polystyrene polymerization or added to the polymer.

In the present invention, it is preferable to add a thermoplastic resin and / or a rubber component to the polystyrene resin. Examples of the thermoplastic resin include polystyrene-based resins such as polystyrene having an atactic structure, AS resin and ABS resin, polyester-based resins such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate, nylon 6, nylon 66, nylon 12, Polyamide resin such as nylon 4, polyhexamethylene adipamide, polyethylene,
Examples thereof include polyolefin resins such as polypropylene and polybutene. The rubber component is preferably a rubbery copolymer containing a styrene compound as its constituent component, and examples thereof include random, block or graft copolymers obtained by copolymerizing at least one selected from styrene and the rubber component. . Examples of such a rubber-like copolymer include styrene-butadiene copolymer rubber, styrene-isoprene block copolymer, rubber obtained by hydrogenating a part or all of these butadiene moieties, methyl acrylate-butadiene- Styrene copolymer rubber, acrylonitrile-butadiene-styrene copolymer rubber,
Examples thereof include acrylonitrile-alkyl acrylate-butadiene-styrene copolymer rubber and methyl methacrylate-alkyl acrylate-butadiene-styrene copolymer rubber. The above-mentioned rubbery copolymer containing a styrene compound as its constituent has a styrene unit, and therefore has good dispersibility mainly in polystyrene resin having a syndiotactic structure, and as a result, polystyrene resin Has a great effect of improving physical properties. In particular, as the compatibility modifier, a rubbery copolymer containing the above-mentioned styrene compound as its constituent component is suitable.

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 and the like can be used.

In the present invention, the weight average molecular weight of the polystyrene resin constituting the film is preferably 10,000.
It is 0 or more, more preferably 50,000 or more. When the weight average molecular weight is less than 10,000, the strength / elongation property and heat resistance of the film are likely to decrease. The upper limit of the weight average molecular weight is not particularly limited, but if it is 1,500,000 or more, breakage may occur due to an increase in stretching tension, so that it is preferably less than 1,500,000.

In the present invention, the heat-shrinkable polystyrene resin film is used to improve electrostatic adhesion, slipperiness, stretchability, processability, impact resistance, etc., roughening, opacifying, and hollowing. For the purpose of weight reduction, other resins, plasticizers, compatibility modifiers, inorganic particles, organic particles, colorants, antioxidants, antistatic agents and the like can be appropriately added.

As the material constituting the film of the present invention,
By using a polystyrene resin as described above,
Excellent in various heat shrinkage properties, excellent printability such as adhesion to ink when forming a label, and no pinholes are formed on the printed surface of the film. Furthermore, it has excellent disposability and has little impact on the environment when incinerated.

The polystyrene resin forming the film as described above is formed into a film by a conventionally used method such as an extrusion method or a calendar method. The shape of the film is, for example, flat or tubular,
There is no particular limitation. As the stretching method, conventionally used methods such as a roll stretching method, a long gap stretching method, a tenter stretching method and a tubular stretching method can be used. In any of the above methods, stretching may be performed by sequential biaxial stretching, simultaneous biaxial stretching, uniaxial stretching, or a combination thereof. In the above-mentioned biaxial stretching, stretching in the longitudinal and transverse directions may be performed simultaneously, but sequential biaxial stretching in which either one is performed first is effective, and the longitudinal and lateral directions may be performed first.
Preferred conditions for producing the heat-shrinkable polystyrene resin film of the present invention are shown below. The draw ratio is preferably 1.0 to 6.0, and the predetermined one direction and the direction orthogonal to the predetermined direction may be the same or different. In the stretching step, the glass transition temperature (Tg) or higher (Tg +
It is preferable to preheat at a temperature of 50 ° C. or less. In heat setting after stretching, it is preferable to pass a heating zone at 30 ° C to 150 ° C for about 1 to 30 seconds after stretching. Further, after the film is stretched and before or after the heat setting, the relaxation treatment may be performed to an appropriate degree. Further, after the stretching, a step of cooling the film while applying a stress to the film while keeping it in a stretched or tensioned state, or a cooling step after releasing the tensioned state following the treatment may be added.

As a factor that the heat shrinkage rate of the long film forming the film roll varies depending on the site, it is considered that the composition variation of the resin component of the film is a major factor. Generally, heat-shrinkable polystyrene-based resin film has the characteristics of the film such as blending two or more kinds of resins or using a resin composed of a plurality of copolymerization monomer components in order to make the heat-shrinking property and the strength compatible with each other. It is changing.
When blending two or more types of resins, after blending raw material chips of multiple types of resins with different configurations with a hopper or the like,
It is melt-kneaded and extruded from an extruder to form a film. For example, when there are three kinds of resins as raw materials, the respective raw material chips are continuously or intermittently supplied to the three hoppers, and if necessary, via the buffer hoppers, finally just before the extruder or While mixing three types of raw material chips with a hopper directly above (hereinafter referred to as “final hopper”), the raw material chips are quantitatively supplied to the extruder according to the extrusion amount of the extruder to form a film. However, depending on the capacity or shape of the final hopper, when the amount of chips in the final hopper is large or the remaining amount is small, the raw material segregation phenomenon occurs in which the mixing ratio of the chips supplied from the final hopper to the extruder is different. It's easy to do. This problem is particularly remarkable when the shape and the specific gravity of the chip are different depending on the resin, and in that case, the heat shrinkage rate easily varies in the long film.

Therefore, in order to obtain a film having a small variation in heat shrinkage in a long film forming one film roll, it is preferable to reduce the composition variation depending on the site of the film. When a plurality of types of resins are used, it is preferable to reduce the variation in the shape of the raw material chips and prevent the raw material segregation phenomenon in the final hopper. Specifically, when the step of mixing a plurality of resins constituting the heat-shrinkable polystyrene-based resin film and melt-extruding is included, the shape of the raw material chips of each resin is columnar and / or elliptic columnar, and the compounding amount is With respect to the raw material chip of the resin having the largest number, the major axis and the minor axis of the cross section perpendicular to the longitudinal direction of the raw material chip of the other resin, and the longitudinal length are within ± 50% of the difference between the average values. Is preferred. In addition, the plane shape of the cross section perpendicular to the longitudinal direction in the above “columnar shape” is not particularly limited to a square shape or a circular shape that can be measured. More preferably, the difference between the major axis and the minor axis and the length in the longitudinal direction is within ± 20%, and particularly preferably, the difference between the average values is within ± 15%. Good. If there is a difference in the size and shape of the raw material chips, when the mixture of chips falls in the final hopper, small chips tend to fall,
When the chips remaining in the final hopper become small, the ratio of large chips increases, which causes the segregation of raw materials.
By segregating the chip size and shape as described above, the raw material segregation can be reduced.

In order to prevent the raw material segregation phenomenon in the final hopper, the resin constituting the heat-shrinkable polystyrene-based resin film is mixed using an extruder equipped with a funnel-shaped hopper as a feed portion for the raw material chips. In the case of including the step of performing melt extrusion, it is also preferable that the inclination angle of the funnel-shaped hypotenuse and the horizontal line segment of the hopper is 65 degrees or more. By setting the inclination angle to 65 degrees or more, the chips can be easily dropped even if there are variations in the shape, and the chips can be lowered with the upper surface horizontal, which is effective in reducing the raw material segregation. is there. More preferably, the inclination angle is 70 degrees or more. A plurality of hoppers may be used upstream of the final hopper. In that case, the inclination angle of any hopper is preferably 65 degrees or more, more preferably 70 degrees or more.

Further, since fine powder generated by collapse or breakage of the raw material chips used promotes the occurrence of raw material segregation, the fine powder generated in the process is removed to reduce the ratio of fine powder in the hopper. Is also preferable. Specifically, the ratio of the fine powder is preferably controlled within 1% by weight, and more preferably within 0.5% by weight throughout the entire process until the raw material chips enter the extruder. Examples of the method for reducing the ratio of the fine powder include a method of removing the fine powder with a sieve when forming chips with a strand cutter, a method of removing the raw chips with a cyclone type air filter, etc. when the raw chips are fed.

As a means for reducing the material segregation in the hopper, a method of optimizing the capacity of the hopper used is also preferable. Specifically, the capacity of the hopper to be used is preferably 15 to 120% by weight, and more preferably 20 to 100% by weight of the discharge amount of the extruder per hour.

Further, as a method of mixing raw material chips of two or more kinds of resins, a hopper (final hopper) directly above the extruder is used.
It is preferable to mix the raw material chips while continuously feeding a fixed amount to the extruder. Further, the raw material chips whose size variation is controlled within the above range may be mixed in advance and then supplied to the final hopper and the extruder through one or more intermediate (buffer) hoppers. When mixing multiple raw material chips, a method of mixing multiple types of raw materials while quantitatively feeding the raw material chips from a device that continuously supplies the raw material chips quantitatively, or using a blender or the like in advance. In the latter case, it is preferable to pay attention to the size of the raw material chips so that the raw material segregation does not occur when the mixture is discharged.

The factors causing the heat shrinkage rate of the long film forming the film roll to vary depending on the site include, in addition to the above-described compositional variations depending on the site of the resin constituting the film,
Variations in the conditions in the process of stretching the film can be mentioned. In the present invention, as another method of reducing the fluctuation of the heat shrinkage ratio in the film roll, a method of suppressing the temperature fluctuation in the step of stretching the film to reduce the surface temperature fluctuation width of the film is also preferable. For example, when uniaxially stretching in the transverse direction using a tenter, there are a preheating step before stretching, a stretching step, a heat treatment step after stretching, a relaxation treatment step, a re-stretching treatment step, etc.
In the stretching step and the heat treatment step after stretching, the fluctuation range of the surface temperature of the film measured at any time in each step is preferably within an average temperature of ± 1 ° C. over the entire length of the film, and more preferably Average temperature ± 0.5
It should be within ℃. When the fluctuation range of the surface temperature of the film is small, stretching and heat treatment are performed at the same temperature over the entire length of the film, and the heat shrinkage behavior becomes uniform. Since the temperature fluctuations in the preheating step, the stretching step, and the heat treatment step after stretching have a great influence on the fluctuation of the heat shrinkage rate,
It is preferable to suppress the temperature fluctuation by using a heating facility or a stretching facility capable of strict temperature control. In addition, it is preferable to suppress the temperature fluctuation in the preheating step and the heat treatment step after stretching.

In the present invention, "the fluctuation range of the surface temperature of the film measured at an arbitrary time point" means, for example, at the time point 2 m has elapsed after the stretching step, the film is continuously produced during the film production. Measure by measuring the surface temperature. Since the average temperature can be calculated at the time when the film production for one roll is completed, if the fluctuation range of the film surface temperature is within the average temperature ± 1 ° C, it means that the film is stretched under the same conditions over the entire length of the film. The fluctuation of the heat shrinkage rate becomes small.

In the present invention, the thickness of the heat-shrinkable polystyrene resin film is not particularly limited, but is 10 to 200.
It is preferably in the range of μm, more preferably 20
It is preferable that the thickness is in the range of ˜100 μm.

The film roll of the present invention is formed by winding the heat-shrinkable polystyrene resin film.
As the winding core, a commonly used core made of plastic or metal such as 3 inch, 6 inch, 8 inch, etc. can be used.

The heat-shrinkable polystyrene-based resin film obtained from the film roll of the present invention is suitably used as a packaging material used for covering, binding, and packaging of containers and the like, and is beautiful by using the film of the present invention. The appearance can be obtained with good reproducibility, and in particular, the label composed of the film of the present invention has excellent covering properties and is suitable for packaging containers. The heat-shrinkable polystyrene-based resin film and label of the present invention can be uniformly coated even on an article having a large coating area or an article having a complicated shape, such as a container having a thin neck. According to the present invention, a heat-shrinkable polystyrene-based resin film having excellent applicability to a heat storage container and capable of stably maintaining its appearance even when exposed to high temperature conditions after shrinkage, and a label from the outside. A heat-shrinkable polystyrene resin film that can protect the packaged item from light and prevent deterioration of the packaged item, and heat that has excellent low-temperature stability and has excellent applicability to aseptic filling packaging and short-time packaging. A shrinkable polystyrene resin film can be obtained. Therefore, the heat-shrinkable polystyrene resin film and label obtained from the film roll of the present invention can be used as various container labels for heat-resistant plastic bottles, glass bottles, metal containers, ceramics and the like.

[0066]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically with reference to Test Examples, Examples and Reference Examples, but the present invention is not limited thereto.

Test Example 1. Test Method (1) Heat Shrinkage Ratio in Steady Region of Film Roll In the film rolls of Examples 1 to 6, Comparative Examples 1 to 12 and Reference Examples 1 to 5, film physical properties are stable with respect to the flow direction during the production of the film. Of the heat-shrinkable polystyrene-based resin film of the portion forming the steady region, the end of the film roll on the winding end side is the start end, and the end on the winding start side is the end, and within 2 m of the inside of the start end. The first cutout portion is provided, and the final cutout portion is provided within 2 m of the inside of the end. Further, every 100 m (including an error range) from the first cutout portion, there is a difference of about ± 1 m. A 10 cm × 10 cm square sample having sides parallel to the longitudinal direction of the film and the direction perpendicular to the film. cut. 1 in hot water in a water bath set to a temperature of 85 ° C for each sample for each cutout
A treatment of dipping for 0 seconds and pulling up, and then dipping in water at 25 ° C. for 10 seconds and pulling up was performed. The length (An: unit cm) of one side that is mainly shrunk (main shrinkage direction) is measured, and the rate of change in length after heat treatment after treatment as HSn (unit:%) is shown below as the heat shrinkage ratio. After calculating using Equation 2,
The average value HSav (unit:%) of the heat shrinkage of each sample is calculated,
HSn-HSav was determined. In addition, in Tables 3, 6, and 9,
The absolute value of the change in heat shrinkage | HSn-HSav | was described as a representative value and set as the range of fluctuation. HSn (%) = [(10−An) / 10] × 100 Formula 2

The above test method will be specifically described. For example, in the case of a film roll composed of a film having a length of 498 m in the steady region, Sample 1 is cut out within a range of 2 m from the winding end side of the film in the steady region. Samples 2 and 2 at a distance of about 100m from Sample 1
Cut out sample 3 at a distance of 00 m, sample 4 at a distance of 300 m, and sample 5 at a distance of 400 m, and the rest is shorter than 100 m, so 2 m from the winding start side of the film.
The sample 6 is cut out within the range. Even in the steady region, the heat shrinkage characteristics on the winding end side and winding start side of the film are more likely to vary than other parts, so 2
Be sure to collect a sample within m. The heat shrinkage rate of each sample is within ± 5% of the average value of the heat shrinkage rate of all the samples, which means that the average value of the heat shrinkage rate of each test piece is HSav.
It means that the difference in the heat shrinkage rate Hsn (%) of the sample piece n with respect to (%), | HSn−HSav |, is less than 5%. That is, the maximum value HSmax of HSn and HS
av difference | HSmax-HSav |, the minimum value H of HSn
It is sufficient that the difference | HSmin−HSav | between Smin and HSav is within 5%.

(2) Maximum heat shrinkage rate From the film rolls of Examples 1 to 6, Comparative Examples 1 to 12 and Reference Examples 1 to 5, the main shrinkage direction was the longitudinal direction, the width was 15 mm at approximately equal intervals, and the length was 6 which becomes 210mm
This heat-shrinkable polystyrene-based resin film was cut and marked with 200 mm intervals in the longitudinal direction to give test pieces.
In the hot air circulation type incubator (manufactured by Peng Seisakusho Co., Ltd., FX-1: damper closed, quick heater ON) set to each temperature from 100 ° C to every 10 ° C to 150 ° C, the test piece was in the center of the incubator. Were left to stand and were heated for 1 minute. After removing the test piece from the incubator and cooling it,
The distance between the marked lines (X ': unit mm) was measured, and the rate of change in length D' (unit%) after the treatment with respect to the length before treatment was calculated using the following formula 3. The maximum value of the length change rate D ′ was defined as the maximum heat shrinkage rate. D ′ (%) = [(200−X ′) / 200] × 100 Formula 3

(3) Transmittance of near-ultraviolet rays A heat-shrinkable film was formed from any part of the film rolls of Examples 1 and 2, Comparative Examples 1 to 4 and Reference Example 1, and the main shrinkage axis direction was rotational symmetry of the following container. It is formed into the label shape of a cylindrical transparent container having a length of 23 cm in the direction perpendicular to the main contraction direction so that it is perpendicular to the axis, and after mounting it in a transparent 1,000 ml PET bottle, Heat shrinkage was performed in the same manner as in the test (7) described later. Connect a measuring instrument with a semiconductor UV sensor (Hamamatsu Photonics, G3614) attached to the tip of a thin rod, calibrate the output and light energy density (mW / cm ² ), and install it in the center of the cap of the mouth of the bottle. The measuring instrument was inserted into the bottle through the hole having a diameter of 5 mm along the axis of rotational symmetry of the bottle. Light source (Matsushita Electric Corporation Black Light Blue FL15BL-
B, 15W, 41 cm) are arranged so that the central axis thereof is 15 cm away from the rotational symmetry axis of the bottle and are arranged substantially parallel to the container, and the direction from the outside to the inside of the container is perpendicular to the rotational symmetry axis of the container. Was irradiated with near ultraviolet rays. The semiconductor UV sensor was moved along the axis of rotational symmetry of the bottle, and the light energy density passing through the film and the bottle was measured at each of the 10 parts from the bottom to the mouth excluding the opaque portion of the bottle (( A1 to A10), and the average value A was determined. Next, the heat-shrinkable polystyrene resin film is removed, and the light energy density of the light transmitted through the transparent container is measured at the same measurement points in the same manner as above (B1 to B1).
0), and this average value B was determined. From A and B above, the average value T of the transmittance of near-ultraviolet rays represented by the following formula 1 was calculated.
The "main shrinkage direction" was measured by measuring the following maximum heat shrinkage ratios in the machine direction and the transverse direction of the film, and the direction having the largest maximum heat shrinkage ratio was defined as the main shrinkage direction. Example, Comparative Example 1
-4, in the film of Reference Example 1, the lateral direction was the main shrinkage direction. T = A / B Formula 1 A: Average value of light energy density (n = 10) transmitted through the film and the container when the heat-shrinkable polystyrene resin film is attached to the transparent container B: Heat-shrinkable polystyrene resin Average value of light energy density (n = 10) transmitted through the transparent container without the resin film attached to the transparent container

(4) Rate of change in length after heat treatment and tension load treatment The heat-shrinkable film was subjected to main shrinkage from any part of the film rolls of Examples 3 and 4, Comparative Examples 5 to 8 and Reference Examples 2 and 3. The test piece was cut into a width of 5 mm and a length of 100 mm, with the direction being the longitudinal direction, and marked lines in the middle in the longitudinal direction at intervals of 50 mm. A weight of 50 g was attached to one end of the test piece using a clip having a weight of 1.18 g, and the other end was fixed by an appropriate jig so that the film and the weight droop. This was placed in a hot air circulation type incubator (manufactured by Peng Seisakusho Co., Ltd., FX-1: damper closed, quick heater ON) set to 110 ° C. so that the test piece was positioned in the center of the incubator, Heated for 1 minute. After taking out the test piece from the incubator and cooling it, the distance (A ′: unit mm) between the marked lines was measured, and heating and tension load treatment (in a temperature 110 ° C. environment, a tension of 51.18 gf was set to 1). The rate of change in length D (unit:%) with respect to the length before the treatment after the load (minute load) is calculated by the following formula 4
Was calculated using. The "main shrinkage direction" was measured by measuring the following maximum heat shrinkage ratios in the machine direction and the transverse direction of the film, and the direction having the largest maximum heat shrinkage ratio was defined as the main shrinkage direction. In the films of Examples, Comparative Examples and Reference Examples, the transverse direction was the main shrinkage direction. D (%) = {(A'-50) / 50} × 100 Formula 4

(5) Heat Shrinkage A heat shrinkable film was formed from any part of the film rolls of Examples 5 and 6, Comparative Examples 9 to 12 and Reference Examples 4 and 5 with a width of 15 mm with the main shrinkage direction being the longitudinal direction. Then, the test piece was cut to have a length of 210 mm and marked with 200 mm intervals in the longitudinal direction. The test piece was immersed in warm water of a water bath set at a temperature of 65 ° C. for 10 seconds. The distance (X ": unit mm) between the marked lines was measured, and the rate of change in length D" (unit:%) with respect to the length before and after the treatment was calculated using the following formula 5. Also, the "main contraction direction" is
The following maximum heat shrinkage rates were measured in the machine direction and the transverse direction of the film, and the direction having the largest maximum heat shrinkage rate was taken as the main shrinkage direction. In the films of Examples, Comparative Examples and Reference Examples, the transverse direction was the main shrinkage direction. D ″ (%) = [(200−X ″) / 200] × 100 Formula 5

(6) Dynamic viscoelasticity Each unstretched sheet obtained in the manufacturing process of the heat-shrinkable polystyrene resin film forming the film roll of Examples 5 and 6, Comparative Examples 9 to 12 and Reference Examples 4 and 5. Was cut into a test piece having a width of 5 mm and a measuring portion length of 30 mm with the MD direction as the longitudinal direction. For the test piece, the dynamic viscoelasticity was measured under the conditions of expansion and contraction mode, frequency of 50 Hz, temperature range of -20 to 250 ° C., and heating rate of 2 ° C./min, and temperature range where alpha dispersion derived from polystyrene was measured. Then, the presence or absence of dispersion other than alpha dispersion was confirmed.

(7) Shrinkage Finishability The total length of the films constituting the film rolls of Examples 1 to 6, Comparative Examples 1 to 12 and Reference Examples 1 to 5 is the same as that of Toyo Ink Mfg. Co., Ltd. (three colors (grass color, gold color, After three-color printing was performed using (white) ink, the film was slit, and a center seal machine was used to solvent-bond it with 1,3-dioxolane to form a tube, which was then wound in two folded states. All of the tubes were cut to a size (full contraction direction was circular cross-section, length in non-contraction direction was 22 cm) to be a full label for PET bottles described below to form labels. Cover the above label on a PET bottle of 1,000 ml and steam tunnel (manufactured by Fuji Astec, SH-1500-
L) was passed through. The conditions in the steam tunnel are
The first zone was 67 ° C., the second zone was 80 ° C., and the tunnel passage time was 10 seconds. All the labels were heat-shrinked in the same manner, and the shrink finish was visually evaluated according to the following criteria. Further, in the following criteria, 4 or more was "passed" and 3 or less was "defective", and the defective rate was calculated according to the following formula 6. The "defects" here are wrinkles, folds in the edge of the label, color spots, and insufficient shrinkage. [Evaluation Criteria] 5: Best Finishing Performance 4: Good Finishing Performance 3: Defects within 2 places 2: Defects 3 to 6 places 1: Defects 6 places or more Defective rate = (number of "defective" / total number of labels) x 100 Formula 6

(8) Heat storage resistance Example 3 used for the evaluation of shrink finish property in the above (7)
~ 6, Comparative Examples 5-12, Reference Examples 2-5 5 bottles (after heating) equipped with labels made of heat-shrinkable polystyrene resin film constituting the film rolls are filled with water by removing air as much as possible, and capped. Sealed by. The bottle was placed sideways on a laboratory hot plate heated to 110 ° C. for 72 hours for Examples 3-4, Comparative Examples 5-8 and Reference Examples 2-3, Examples 5-6, Comparative Examples 9 to 12 and Reference Examples 4 to 5 were left standing for 24 hours, and then the state of the label was visually evaluated according to the following criteria. ◯: There are not many defects on the label, which is good Δ: Defects are clearly recognized on the label, which is not good ×: There are many defects on the label and they are defective

(9) Dimension of Raw Material Chip Raw materials of each polymer used for producing heat-shrinkable polystyrene resin films constituting the film rolls of Examples 1 to 6, Comparative Examples 1 to 12 and Reference Examples 1 to 5 100 chips were randomly sampled from each chip, and each dimension, that is, the major axis and minor axis of the cross section perpendicular to the longitudinal direction, and the longitudinal length (units are all mm) were decimal points using calipers. The measurement was performed up to one digit, and the average value was obtained. Calculate the difference between the average value of each dimension in the raw material chip of the main resin (the resin with the highest compounding amount) and the average value of each dimension in the raw material chips of other resins, and The percentage was calculated.

2. Test results The results of the above tests (1) to (9) are shown in Tables 3, 6, and 9.

[0078]

EXAMPLE 1 Syndiotactic polystyrene (weight average molecular weight 300,000) obtained by copolymerizing 40 mol% of 4-methylstyrene as a constituent was used as a lubricant, and calcium carbonate particles having an average particle diameter of 1.0 μm were used. Raw material chips of the main resin mixed and mixed so as to be 0.05% by weight, and raw material chips of styrene-butadiene block copolymer (rubber component) obtained by copolymerizing styrene as a constituent component so as to be 40 wt% A raw material chip of high styrene rubber (styrene-butadiene copolymer rubber, containing styrene as a constituent component so as to be 85 wt%) as a modifier for compatibility adjustment, the shape and size are shown in Table 2, and the weight is It is fed by a fixed amount screw feeder so that the ratio becomes 65: 30: 5 (main resin / rubber component / modifier), It was mixed in the hopper inclination angle 70 degrees directly above extruder.
This was melted at 250 ° C., extruded from a T-die having a lip gap of 800 μm, and brought into close contact with a cooling roll at 40 ° C. by an air knife method to solidify by cooling to obtain an amorphous sheet. At this time, 150 k of raw chips are placed in the hopper.
g was retained. The amorphous sheet was preheated to 110 ° C., stretched at a stretching temperature of 90 ° C. in the transverse direction by a draw ratio of 5.0 times, and then heat-set at 60 ° C. for 15 seconds to obtain 1,000 m.
A heat-shrinkable polystyrene resin film having a thickness of 50 μm was continuously formed over the above. The fluctuation range of the surface temperature during the film formation is the average temperature ± 0.8 ° C in the preheating step,
The average temperature was ± 0.6 ° C in the stretching step, and the average temperature was ± 0.5 ° C in the heat setting step. Width of the resulting film 4
It was slit into a length of 00 mm and a length of 1,000 m, and wound into a 3-inch paper can to obtain a film roll. An image was formed on the entire surface of one side of the obtained film by halftone printing, and this was used as an example.

Example 2 Styrene-grafted styrene-butadiene rubber obtained by graft-copolymerizing styrene on a styrene-butadiene copolymer (25% by weight of styrene) with a modifier having the shape and size of raw material chips as shown in Table 2. (Graft ratio 100% by weight), the fluctuation range of the surface temperature at the time of film formation, the average temperature ± 0.8 ℃ in the preheating step, the average temperature ± in the stretching step
A film roll was obtained in the same manner as in Example 1 except that the temperature was 0.5 ° C. and the average temperature was ± 0.8 ° C. in the heat setting step.

Comparative Example 1 A film roll was obtained in the same manner as in Example 1 except that the shape and size of the raw material chips were as shown in Table 2 and the stretching ratio was 2.0.

Comparative Example 2 A film roll was obtained in the same manner as in Example 1 except that the shape and size of the raw material chips were as shown in Table 2 and a hopper having an inclination angle of 60 degrees was used.

Comparative Example 3 The shape and size of the raw material chips are shown in Table 2, and the fluctuation range of the surface temperature at the time of film formation is such that the average temperature ± 1.0 ° C. in the preheating step and the average temperature ± 2. A film roll was obtained in the same manner as in Example 1 except that the temperature was 5 ° C and the average temperature was ± 2.0 ° C in the heat setting step.

Comparative Example 4 The shape and size of the raw material chips are shown in Table 2, and the fluctuation range of the surface temperature at the time of film formation is shown as an average temperature ± 1.0 ° C. in the preheating step and an average temperature ± 2. A film roll was obtained in the same manner as in Example 1 except that the temperature was 5 ° C and the average temperature was ± 2.0 ° C in the heat setting step.

Reference Example 1 The shape and size of the raw material chips were as shown in Table 2, and the main resin polystyrene was syndiotactic polystyrene containing no copolymerization component, and the mixing ratio of the main resin, the rubber component and the modifier was set. , 50: 0 by weight ratio (main resin /
A film roll was obtained in the same manner as in Example 1 except that the rubber component / modifying agent was used.

Example 3 A syndiotactic polystyrene (weight average molecular weight 300,000) obtained by copolymerizing 30 mol% of 4-methylstyrene was used as the polystyrene resin of the main resin, and the shape and size of the raw material chips are shown in Table 5. The weight ratio of the main resin, the rubber component and the modifier is 75: 2.
A film roll was obtained in the same manner as in Example 1 except that the ratio was 0 to 5 (main resin / rubber component / modifier), and the obtained film was not subjected to halftone printing.

Example 4 Styrene-grafted styrene-butadiene rubber obtained by graft-copolymerizing styrene onto a styrene-butadiene copolymer (styrene content 25% by weight) with the shape and size of raw material chips as shown in Table 5. (Graft ratio 100% by weight), the fluctuation range of the surface temperature at the time of film formation, the average temperature ± 0.8 ℃ in the preheating step, the average temperature ± in the stretching step
A film roll was obtained in the same manner as in Example 3 except that the temperature was 0.5 ° C. and the average temperature was ± 0.8 ° C. in the heat setting step.

Comparative Example 5 A film roll was obtained in the same manner as in Example 3 except that the shape and size of the raw material chips were as shown in Table 5 and the draw ratio was 2.0.

Comparative Example 6 A film roll was obtained in the same manner as in Example 3 except that the shape and size of the raw material chips were set as shown in Table 5 and the hopper having the inclination angle of 60 degrees was used.

Comparative Example 7 The shape and size of the raw material chips are set as shown in Table 5, and the fluctuation range of the surface temperature at the time of film formation is shown as an average temperature ± 1.0 ° C. in the preheating step and an average temperature ± 2. A film roll was obtained in the same manner as in Example 3 except that the temperature was 5 ° C. and the average temperature was ± 2.0 ° C. in the heat setting step.

Comparative Example 8 The shape and size of the raw material chips are set as shown in Table 5, and the fluctuation range of the surface temperature at the time of film formation is controlled by the average temperature ± 1.0 ° C. in the preheating step and the average temperature ± 2. A film roll was obtained in the same manner as in Example 3 except that the temperature was 5 ° C. and the average temperature was ± 2.0 ° C. in the heat setting step.

Reference Example 2 The shape and size of the raw material chips are as shown in Table 5, the main resin polystyrene is syndiotactic polystyrene containing no copolymerization component, and the mixing ratio of the main resin, the rubber component and the modifier is , 50: 0 by weight ratio (main resin /
A film roll was obtained in the same manner as in Example 3 except that the rubber component / modifying agent was used.

Reference Example 3 A film roll was obtained in the same manner as in Example 3, except that the shape and size of the raw material chips were set as shown in Table 5 and polystyrene as the main resin was changed to atactic polystyrene.

Example 5 A syndiotactic polystyrene (weight average molecular weight 300,000) obtained by copolymerizing 4-methylstyrene in an amount of 33 mol% was used as the main resin polystyrene resin. The weight ratio of the main resin, the rubber component and the modifier is 55: 4.
A film roll was prepared in the same manner as in Example 1 except that the ratio was 0 to 5 (main resin / rubber component / modifier), the draw ratio was 6.0 times, and the obtained film was not subjected to halftone printing. Got

Example 6 Styrene-grafted styrene-butadiene rubber obtained by graft-copolymerizing styrene onto a styrene-butadiene copolymer (25% by weight of styrene) with a modifier having the shape and size of raw material chips as shown in Table 8. (Graft ratio 100% by weight), the fluctuation range of the surface temperature at the time of film formation, the average temperature ± 0.8 ℃ in the preheating step, the average temperature ± in the stretching step
A film roll was obtained in the same manner as in Example 5 except that the temperature was 0.5 ° C. and the average temperature was ± 0.8 ° C. in the heat setting step.

Comparative Example 9 A film roll was obtained in the same manner as in Example 5, except that the shape and size of the raw material chips were as shown in Table 8 and the draw ratio was 2.0.

Comparative Example 10 A film roll was obtained in the same manner as in Example 5 except that the shape and size of the raw material chips were set as shown in Table 8 and the hopper having the inclination angle of 60 degrees was used.

Comparative Example 11 The shape and size of the raw material chips are set as shown in Table 8, and the fluctuation range of the surface temperature at the time of forming a film is ± 1.0 ° C. in the preheating step and ± 2 ° C. in the stretching step. A film roll was obtained in the same manner as in Example 5, except that the temperature was 5 ° C. and the average temperature was ± 2.0 ° C. in the heat setting step.

Comparative Example 12 The shape and size of the raw material chips are set as shown in Table 8, and the fluctuation range of the surface temperature during the film formation is ± 1.0 ° C. in the preheating step and ± 2 ° C. in the stretching step. A film roll was obtained in the same manner as in Example 5, except that the temperature was 5 ° C. and the average temperature was ± 2.0 ° C. in the heat setting step.

Reference Example 4 The shape and size of the raw material chips are as shown in Table 8, the main resin polystyrene is syndiotactic polystyrene containing no copolymerization component, and the mixing ratio of the main resin, the rubber component and the modifier is , 50: 0 by weight ratio (main resin /
A film roll was obtained in the same manner as in Example 5, except that the rubber component / modifying agent was used.

Reference Example 5 A film roll was obtained in the same manner as in Example 5, except that the shape and size of the raw material chips were set as shown in Table 8 and polystyrene as the main resin was changed to atactic polystyrene.

The constituent materials of the heat-shrinkable polystyrene resin film rolls of the above Examples, Comparative Examples, and Examples in Tables 1, 4, and 7 below are as follows. (1) Main resin PS1: 4-methylstyrene copolymer syndiotactic polystyrene PS2: syndiotactic polystyrene PS3: actotactic polystyrene (2) rubber component G1: styrene (40 wt%)-butadiene copolymer (3) modified Material a: High styrene rubber (styrene 85 wt%) b: Styrene-grafted styrene-butadiene rubber

[0102]

[Table 1]

[0103]

[Table 2]

[0104]

[Table 3]

[0105]

[Table 4]

[0106]

[Table 5]

[0107]

[Table 6]

[0108]

[Table 7]

[0109]

[Table 8]

[0110]

[Table 9]

[0111]

The film obtained from the heat-shrinkable polystyrene-based resin film roll of the present invention has a sufficiently large heat-shrinkage factor for practical use, and is uniform during heat-shrinking regardless of temperature fluctuations and nonuniformity in the shrinking step. It shrinks to the right, without uneven shrinkage and has a beautiful appearance. For the film obtained from any part of the film roll, protect the object to be packaged from external mechanical stimuli and light rays, prevent deterioration of the object to be packaged, or even if exposed to high temperature conditions after shrinkage Slack and wrinkles do not occur, its appearance can be stably maintained,
It is possible to obtain a film roll that can reduce variations in properties such as having a sufficient heat shrinkage factor even in the low temperature heat shrinkage step and can improve the yield even when used as a label or the like.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 7:00 B29L 7:00 (72) Inventor Satoshi Hayakawa 344 Maebata, Kizu, Ai, Inuyama, Aichi Spinning Co., Ltd. Inuyama Plant (72) Inventor Nori Tabota 344 Maebata, Kizu, Inuyama City, Aichi Toyobo Co., Ltd. Inuyama Plant (72) Inventor Shigeru Yoneda 2-2-1 Dojimahama, Kita-ku, Osaka No. 8 Toyobo Co., Ltd. In-house (72) Inventor Katsuhiko Nose 2-8 Dojimahama, Kita-ku, Osaka City, Osaka Prefecture Toyobo Co., Ltd. In-house F-term (reference) 4F207 AA13 AG01 AL08 AL12 KA01 KA17 KF12 4F210 AA13 AA13A AE01 AG01 RA03 RC02 RG02 RG04 RG43

Claims (15)

[Claims] 1. A film roll obtained by winding a heat-shrinkable polystyrene-based resin film, wherein the heat-shrinkable polystyrene-based resin film has stable film physical properties in the flow direction during the production of the film. In the steady region, start the end of the film roll on the winding end side,
The end on the winding start side is the end, the first cutout is provided within 2 m of the inside of the start end, and a cutout is provided about every 100 m from the first cutout. When the heat shrinkage rate of each sample after the treatment of immersing the cut-out sample in the hot water temperature of 85 ° C. for 10 seconds was measured by the rate of change in length in the main shrinkage direction before the treatment, the heat shrinkage rate of each sample was measured. Is within ± 5% of the average value of the heat shrinkage rate of all the samples, a heat shrinkable polystyrene resin film roll. 2. A sample obtained by cutting the heat-shrinkable polystyrene-based resin film so as to have a width of 15 mm and a length of 210 mm has marked lines at intervals of 200 mm in the main shrinkage direction, and in the main shrinkage direction of the sample. , 100 ° C to 10
The maximum heat shrinkage rate, which is the maximum value of the rate of change in length with respect to the length between the marked lines before the treatment, after the treatment of heating for 1 minute at each temperature up to 150 ° C. at each temperature is 40% or more. The heat-shrinkable polystyrene-based resin film roll according to claim 1. 3. The heat-shrinkable polystyrene resin film is attached to a bottle as a label shape of a cylindrical tubular transparent container whose main shrinking direction is a cylindrical cross-sectional direction,
The average value T of the transmittance of near-ultraviolet light represented by the following formula 1 is 0.5 or less when the near-ultraviolet light is irradiated from the outside of the container to the inside after heat shrinking from the direction perpendicular to the axis of rotational symmetry of the container. The heat-shrinkable styrene resin film roll according to claim 1, wherein T = A / B Formula 1 A: Average value of light energy density (n = 10) transmitted through the film and the container when the heat-shrinkable polystyrene resin film is attached to the transparent container B: Heat-shrinkable polystyrene resin Average value of light energy density (n = 10) transmitted through the transparent container without the resin film attached to the transparent container 4. The heat-shrinkable polystyrene-based resin film has a width of 5 mm and a length of 10 with the main shrink direction being the longitudinal direction.
In the middle of the sample cut out to 0 mm, marked lines are marked at intervals of 50 mm in the longitudinal direction, and a tension of 51.18 gf is applied for 1 minute in an environment of a temperature of 110 ° C. in the main shrinkage direction of the sample. The heat-shrinkable styrene-based resin film roll according to claim 1, wherein the rate of change in length with respect to the length between the marked lines before the treatment is 0% or more and 90% or less. 5. A sample obtained by cutting the heat-shrinkable polystyrene-based resin film so as to have a width of 15 mm and a length of 210 mm is marked with a line of 200 mm in the main shrinkage direction in the main shrinkage direction of the sample. The heat shrinkage ratio, which is indicated by the rate of change in length between marked lines after the treatment of immersing in hot water at a temperature of 65 ° C for 10 seconds, is 5% or more. The heat-shrinkable polystyrene resin film roll described. 6. The heat-shrinkable polystyrene-based resin film has a stretching mode, a frequency of 50 Hz, and −20 ° C. to 250.
In the dynamic viscoelasticity measurement of the film under the condition of temperature range of ℃, temperature rising rate of 2 ℃ / min, dispersion other than alpha dispersion is measured in the temperature range where alpha dispersion derived from polystyrene is measured. The heat-shrinkable polystyrene resin film roll according to claim 1. 7. The heat-shrinkable polystyrene-based resin film is an unstretched sheet of the heat-shrinkable polystyrene-based resin film which has not been stretched.
z, a temperature range of -20 ° C to 250 ° C, and a temperature range in which the alpha dispersion derived from polystyrene is measured in the measurement of the dynamic viscoelasticity of the film under the condition of the temperature rising rate of 2 ° C / min.
The heat-shrinkable polystyrene-based resin film roll according to claim 1, wherein the unstretched sheet whose dispersion other than alpha dispersion is measured is stretched. 8. The heat-shrinkable polystyrene resin film roll according to claim 1, wherein the heat-shrinkable polystyrene resin film has a width of 200 mm or more and a length of 300 m or more. 9. The heat-shrinkable polystyrene resin film roll according to claim 1, further comprising a polystyrene resin having a syndiotactic structure. 10. The heat-shrinkable polystyrene resin film roll according to claim 1, wherein the heat-shrinkable polystyrene resin film is made of two or more kinds of resins having different constitutions. 11. A step of mixing and melt-extruding resins constituting a heat-shrinkable polystyrene resin film,
The shape of the raw material chip of each resin is columnar and / or elliptical, and the major axis and the minor axis of the cross section perpendicular to the longitudinal direction of the raw material chip of the other resin with respect to the raw material chip of the resin with the largest compounding amount, the longitudinal direction. The method for producing a heat-shrinkable polystyrene film roll according to claim 10, wherein each of the lengths of the heat-shrinkable polystyrene film rolls is within ± 50% with respect to the difference in average value. 12. The funnel of the hopper, which comprises the step of mixing and melt-extruding the resin constituting the heat-shrinkable polystyrene resin film by using an extruder equipped with a funnel-shaped hopper as a feed unit for the raw material chips. The method for producing a heat-shrinkable resin film roll according to claim 10, wherein an inclination angle which is an angle formed by the oblique line and the horizontal line segment is 65 degrees or more. 13. A fluctuation range of a surface temperature of a film, which includes a preheating step, a stretching step, and a heat treatment step, and is measured at any time in each step, within a range of an average temperature ± 1 ° C. over the entire length of the film. Claim 1 characterized by the above.
The method for producing a heat-shrinkable polystyrene-based resin film roll according to 1. 14. A heat-shrinkable polystyrene resin film obtained from the heat-shrinkable polystyrene resin film roll according to claim 1. 15. A heat-shrinkable label comprising the heat-shrinkable polystyrene resin film according to claim 14.