JP5162270B2 - Label adhesive sheet, label and method for producing label adhesive sheet - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive sheet for labels, a label, and a method for producing a pressure-sensitive adhesive sheet for labels.

In recent years, recycling (recycling) of OA equipment and home appliances has been actively performed.
Generally, polystyrene-based resins such as polystyrene (PS) and acrylonitrile / butadiene / styrene (ABS) are suitably used for OA equipment and housings for home appliances. In addition, labels for displaying cautions and warnings are usually attached to these enclosures. In general, when recycling these enclosures, it is necessary to remove the label attached from the enclosure.

  By the way, such a label is manufactured by printing a pressure sensitive adhesive sheet provided with a pressure sensitive adhesive layer on a film base material and cutting it into a predetermined shape. As a pressure-sensitive adhesive sheet that can be used for the label as described above, a pressure-sensitive adhesive sheet using a polystyrene-based resin as a film base material has been studied (for example, see Patent Document 1). Since the label using such an adhesive sheet is made of a resin of the same type as the casing, it is not necessary to remove the label from the casing when the casing is recycled. For this reason, when such a label is used, the work at the time of recycling can be simplified.

  However, in general, polystyrene resins have a disadvantage that they are easily broken when they are formed into a sheet shape. For this reason, when such an adhesive sheet was used for production of a label, there existed the following problems at the time of manufacture of a label. That is, in order to obtain a label cut into a predetermined shape from the pressure-sensitive adhesive sheet, a cut of a predetermined shape is formed in the pressure-sensitive adhesive sheet, and unnecessary portions (cass) that are not used as labels for the pressure-sensitive adhesive sheet are peeled off from the release sheet. In general, the removal work (scrap raising) is generally performed. At this time, the conventional pressure-sensitive adhesive sheet easily breaks because the film base of the pressure-sensitive adhesive sheet is easily torn. For this reason, every time the residue is cut, the residue raising is interrupted and the label cannot be manufactured efficiently.

Japanese Patent Laid-Open No. 10-105063

  An object of the present invention is to produce a label pressure-sensitive adhesive sheet that is excellent in recyclability, suppresses chipping, and can efficiently produce a label, a method for producing a label pressure-sensitive adhesive sheet, and the label pressure-sensitive adhesive sheet. Is to provide a good label.

Such an object is achieved by the present inventions (1) to (10) below.
(1) a band-shaped film substrate made of polystyrene resin;
Having an adhesive layer provided on one side of the film substrate;
The film base material is torn according to JIS K 7128-1 with respect to the width direction of the film base material (direction of 90 ° with respect to the film forming direction when the film base material is formed). When the strength test is performed, the tear starting point formed on the test piece of the film base, and a distance of 3.0 cm from the start point in the width direction of the film base, longitudinal straight line connecting a point crossing the tear line parallel to (film forming direction when the film substrate is a film) is, to name a width direction and an angle of less than ± 30 ° of the substrate,
The film substrate has a tear strength of 1500 mN / mm or more when the tear strength test is performed in the longitudinal direction.
The tear strength when the tear strength test is performed with respect to the width direction is 1500 mN / mm or more,
When the film substrate is subjected to the tear strength test in the longitudinal direction and the width direction, the ratio of the tear strength in the longitudinal direction to the tear strength in the width direction is 0.70. 1.30,
The film substrate has a tensile elongation at break of 80% or more as measured in accordance with ASTM D882 for the longitudinal direction,
A pressure-sensitive adhesive sheet for labels, wherein the tensile breaking elongation measured according to ASTM D 882 in the width direction is 80% or more .

(2) The pressure-sensitive adhesive sheet for labels according to (1), wherein the film substrate is an unstretched film .

( 3 ) The pressure-sensitive adhesive sheet for labels according to (1) or (2) , wherein the polystyrene-based resin contains an impact-resistant polystyrene resin.
(4) The pressure-sensitive adhesive sheet for labels according to any one of (3), wherein the rubber component of the impact-resistant polystyrene resin is styrene-butadiene rubber.
(5) The label according to (4), wherein the styrene-butadiene copolymer ratio (styrene: butadiene), which is a monomer component of the styrene-butadiene rubber, is 30:70 to 60:40 in terms of mass ratio. Adhesive sheet.
(6) The pressure-sensitive adhesive sheet for labels according to (4) or (5), wherein the content of the styrene-butadiene rubber in the impact-resistant polystyrene resin is 20 to 60 wt%.
(7) The film substrate includes a thermoplastic elastomer,
Content of the said thermoplastic elastomer in the said film base material is a pressure-sensitive adhesive sheet for labels in any one of said (1) thru | or (6) which are 5.0-30 wt%.
(8) The pressure-sensitive adhesive sheet for labels according to (7), wherein the thermoplastic elastomer comprises a styrene-butadiene-styrene block copolymer.

( 9 ) a base material forming step of forming a band-shaped film base material made of polystyrene resin by an inflation method;
Having an adhesive layer forming step of forming an adhesive layer on one side of the film substrate;
The film substrate was subjected to a tear strength test performed in accordance with JIS K 7128-1 with respect to the width direction of the film substrate (90 ° direction with respect to the film forming direction of the film substrate). The starting point of the tear formed on the test piece of the film base, and a distance of 3.0 cm from the start point in the width direction of the film base, the longitudinal direction of the film base (the film base line film forming direction) in a straight line parallel of wood is connecting the point of intersection in tearing the can, to name a width direction and an angle of less than ± 30 ° of the substrate,
The film substrate has a tear strength of 1500 mN / mm or more when the tear strength test is performed in the longitudinal direction.
The tear strength when the tear strength test is performed with respect to the width direction is 1500 mN / mm or more,
When the film substrate is subjected to the tear strength test in the longitudinal direction and the width direction, the ratio of the tear strength in the longitudinal direction to the tear strength in the width direction is 0.70. 1.30,
The film substrate has a tensile elongation at break of 80% or more as measured in accordance with ASTM D882 for the longitudinal direction,
A method for producing a pressure-sensitive adhesive sheet for labels, wherein the tensile breaking elongation measured according to ASTM D 882 in the width direction is 80% or more .

(10) A label produced by the label pressure-sensitive adhesive sheet according to any one of (1) to ( 8 ).

  According to the present invention, the pressure-sensitive adhesive sheet for labels and the label pressure-sensitive adhesive sheet can be efficiently produced with excellent recyclability and with no waste of chips, and the label pressure-sensitive adhesive sheet. A label can be provided.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing an example of the pressure-sensitive adhesive sheet for labels of the present invention, FIG. 2 is a plan view showing an example of the pressure-sensitive adhesive sheet for labels of the present invention, and FIG. FIG. 4 is a perspective view showing an outline of a tear strength test performed on the film substrate of the pressure-sensitive adhesive sheet for labels, and FIG. It is a perspective view which shows a part of adhesive sheet for labels.

≪Label adhesive sheet≫
The label pressure-sensitive adhesive sheet of the present invention is used for producing a label. The label can be obtained, for example, by printing the surface of the pressure-sensitive adhesive sheet for labels on the film substrate and cutting it into a predetermined shape.

  As shown in FIG. 1, the label pressure-sensitive adhesive sheet 1 includes a film base material 11, a pressure-sensitive adhesive layer 12 provided on one surface side of the film base material 11, and a side opposite to the film base material 11 of the pressure-sensitive adhesive layer 12. And a release sheet 13 provided on the surface.

  Moreover, as shown in FIG. 2, the adhesive sheet 1 for labels is a sheet | seat whose external shape makes a strip | belt shape.

  The label pressure-sensitive adhesive sheet 1 may be for forming a label of any shape. In this embodiment, the label pressure-sensitive adhesive sheet 1 includes a plurality of substantially rectangular label portions arranged in an island shape. 14 and a residue portion 15 other than the label portion 14 will be described. The label pressure-sensitive adhesive sheet 1 can form only the label portion 14 on the release sheet 13 through an operation of peeling and removing from the release sheet 13 using the residue portion 15 as a residue (unnecessary portion).

Hereinafter, each layer which comprises the adhesive sheet 1 for labels is demonstrated in detail.
<Film base>
The film substrate 11 is a belt-like sheet, and has a function of imparting physical strength such as rigidity and flexibility to the label pressure-sensitive adhesive sheet 1.

  Moreover, the film base material 11 is comprised with the polystyrene-type resin. Thereby, the label manufactured using the adhesive sheet 1 for labels becomes the thing excellent in recyclability. This is due to the following reasons. As for the electronic device and the OA device, the casing is generally made of a polystyrene resin, like the film substrate 11. For this reason, an electronic device or an OA device having such a label affixed to a housing can be molded with a new resin product after being crushed or kneaded while the label is affixed when the housing is recycled. For this reason, when manufacturing a new resin product using a housing, it is not necessary to peel off the label attached to the housing, and the recycling work is simplified.

  However, conventional label pressure-sensitive adhesive sheets using polystyrene-based resins as film substrates have been difficult to produce labels efficiently. That is, since the polystyrene resin is comparatively brittle and easily torn, a phenomenon that the thin residue is broken (scrap breakage) frequently occurs in the process of removing the residue of the adhesive sheet for labels as residue. In such a case, the debris portion that should be originally removed remains on the release sheet, and the debris raising operation needs to be performed individually again. In particular, when the residue is continuously removed from the release sheet while being wound with a roller, an operation for winding the residue again on the roller is required, resulting in poor productivity. In particular, from the viewpoint of resource saving and productivity, when the area of the debris portion is reduced to increase the area of the label portion, the debris tends to become thin, and the above-described problem (debris breakage) occurs remarkably. Was.

Therefore, as a result of intensive studies, the present inventor has completed the following present invention.
The pressure-sensitive adhesive sheet for labels of the present invention is characterized in that the film substrate satisfies the following conditions.
That is, the film base material is torn according to JIS K 7128-1 with respect to the width direction of the film base material (direction of 90 ° with respect to the film forming direction when the film base material is formed). When the strength test is performed, the tear starting point formed on the film base test piece, and the distance of 3.0 cm from the starting point in the width direction of the film base, the longitudinal direction of the film base ( A straight line connecting a point where a straight line parallel to the tearing direction when the film base material is formed) forms an angle of ± 30 ° or less with the width direction of the film base material. .

  The longitudinal direction of the film substrate (hereinafter also referred to as the MD direction and the film forming direction) coincides with the film forming direction when forming the film substrate, and the width direction of the film substrate (hereinafter referred to as the film forming direction). (Also referred to as CD direction) is a direction of 90 ° with respect to the film forming direction when the film substrate is formed.

Details will be described below.
In FIG. 3, the test piece 11 ′ is a part of the film substrate 11. As for test piece 11 ', the long side direction of test piece 11' becomes the width direction (CD direction) of film base material 11, and the short side direction of test piece 11 'is the longitudinal direction of film base material 11 ( (MD direction). Moreover, test piece 11 'is provided with the slit S along the CD direction in the center part of MD direction. A tear strength test is performed using such a test piece 11 '.

  In FIG. 4, the end 111 and the end 112 of the test piece 11 ′ are held and fixed by the gripping tool 20 </ b> A and the gripping tool 20 </ b> B, respectively. The tear strength test is performed by moving the gripping tool 20A and the gripping tool 20B at a predetermined speed in a direction away from the gripping tool 20A and the gripping tool 20B.

  In this tear strength test, as the gripping tool 20A and the gripping tool 20B are separated, the test piece 11 ′ is torn from the end A inside the test piece 11 ′ of the slit S, and is torn starting from the end A. (Cut) t occurs.

In the present invention, the tear t satisfies the following conditions.
First, the film base material 11 is set to a point B where a tear line t intersects with a straight line 1 which is a distance of 3 cm in the CD direction from the starting point A of the tear t and is parallel to the MD direction. The present invention is characterized in that an angle formed by a straight line AB connecting the start point A and the point B with the CD direction is ± 30 ° or less. In other words, the present invention is characterized in that ∠BAC is 30 ° or less when a point having a distance of 3 cm from the start point A in the width direction (on the same straight line of the slit s and in the tearing direction) is point C. .

  When the tear t in the tear strength test of the film substrate 11 satisfies such a condition, the label pressure-sensitive adhesive sheet 1 is suitably prevented from being broken during production of the label.

  This is considered as follows. Since the label pressure-sensitive adhesive sheet 1 has a strip shape, the residue raising can usually be performed by peeling the residue in the MD direction. At this time, as shown in FIG. 5, the direction in which the debris portion 15 is peeled off is f1, and the debris portion 15 to be peeled receives a force in the direction of f1. On the other hand, since the debris part 15 to be peeled is adhered to the release sheet 13, a force acts in the direction of f2 at the time of peeling. Thereby, a breaking force is generated in the residue portion 15. Thereby, the debris part 15 may eventually be cut off laterally with respect to the MD direction. Particularly, for example, in the dregs portion 15 as shown in FIG. 2, the breaking force tends to concentrate on the corner portion 151 that is in contact with the corner of the label portion 14, and the dregs portion 15 is likely to be cut off using such a corner portion 151 as a base point.

  On the other hand, in the pressure-sensitive adhesive sheet 1 for labels of the present invention, the tear t in the tear strength test satisfies the above-described conditions. When the heel BAC as described above is relatively small, the label pressure-sensitive adhesive sheet 1 of the present invention has a relatively high resistance to tearing in the MD direction. For this reason, it is considered that the cut portion 15 is less likely to be cut and the cut portion is prevented.

  In addition, the casing of the electronic device or OA device may be reused (reused) as it is without being crushed or reshaped. In such a case, it is necessary to peel off the attached label. A conventional label using a pressure-sensitive adhesive sheet for labeling (reproducible) is easily cut off in a specific direction when the label is peeled from the casing, and has poor workability. However, the label using the pressure-sensitive adhesive sheet for labels of the present invention satisfies the above-described relationship, so that it is prevented from being cut in a specific direction when being peeled from the casing, and can be easily peeled off. .

  On the other hand, when the tear t does not satisfy the above-described conditions, the effect of the present invention cannot be obtained. That is, the resistance to tearing in the MD direction is not sufficient, and at the boundary between the debris part and the label part, the breaking force concentrates on the part having the corner of the boundary. As a result, the scrap breaks frequently when the scrap is raised.

  Moreover, although the above-mentioned ∠BAC should just be the range as mentioned above, it is preferable that it is 25 degrees or less, and it is more preferable that it is 20 degrees or less. As a result, there is particularly little scrap loss when raising the scrap.

  In the tear strength test, the tear t normally proceeds in the right direction in FIG. 3, and the point B is uniquely obtained.

  The film substrate 11 has a tear strength in the longitudinal direction with respect to a tear strength in the width direction when the tear strength test as described above is performed in the width direction (CD direction) and in the longitudinal direction (MD direction). The ratio is preferably 0.70 to 1.30, more preferably 0.80 to 1.20. As a result, the occurrence of chip breakage at the time of scrap raising is more reliably prevented. This is because when the tear strength is close in the longitudinal direction and the width direction in this way, when the residue is raised, the force applied to the residue 15 at the time of peeling is prevented from being concentrated in a specific direction. It is thought that the cuts were particularly difficult to enter. In addition, since the tear strength of the film base material 11 is sufficiently close in the width direction and the longitudinal direction as described above, the label is difficult to break even when the casing is reused and the label is peeled off.

  The tear strength when the tear strength test as described above in the longitudinal direction of the film substrate 11 is performed is preferably 1500 mN / mm or more, more preferably 2000 mN / mm or more, and 2500 mN. / Mm or more is more preferable. As a result, the label pressure-sensitive adhesive sheet 1 is particularly difficult to have a cut in the longitudinal direction when the residue is raised, and the residue is particularly less likely to break. Further, the manufactured label is particularly difficult to cut in the longitudinal direction even when the casing is reused and the label is peeled off.

  The tear strength when the tear strength test as described above in the width direction of the film substrate 11 is performed is preferably 1500 mN / mm or more, more preferably 2000 mN / mm or more, and 2500 mN. / Mm or more is more preferable. As a result, the label pressure-sensitive adhesive sheet 1 is particularly difficult to have a cut in the width direction when the residue is raised, and the residue is particularly less likely to break. Further, the produced label is particularly difficult to cut in the width direction even when the casing is reused and the label is peeled off.

  Further, the film base 11 preferably has a tensile elongation at break of 80% or more, more preferably 90% or more, more preferably 100% or more as measured in accordance with ASTM D882 in the longitudinal direction. More preferably it is. The upper limit is about 160%. Thereby, even if the adhesive sheet 1 for labels is a case where comparatively strong force is applied to the dregs part at the time of dregs raising, the film base material 11 extends flexibly, and a cut is generated in the dregs part 15. Is prevented. Further, the manufactured label can be suitably prevented from having a cut in the longitudinal direction even when the casing is reused and the label is peeled off.

  Further, the film base 11 preferably has a tensile elongation at break of 80% or more, more preferably 90% or more, more preferably 100% or more as measured in accordance with ASTM D882 in the width direction. More preferably it is. The upper limit is about 160%. As a result, the label pressure-sensitive adhesive sheet 1 has a break in the residue portion 15 due to the flexible extension of the film substrate 11 even when a relatively strong force is applied to the residue portion 15 when raising the residue. It is prevented. Further, the manufactured label can be suitably prevented from having a cut in the width direction even when the casing is reused and the label is peeled off.

  As described above, the film base 11 is mainly composed of a polystyrene-based resin.

  The polystyrene resin that can be used for the film substrate 11 is not particularly limited. For example, polystyrene resin (GPPS resin), impact-resistant polystyrene resin (HIPS resin) obtained by graft-polymerizing styrene to a rubber component, GPPS, and the like. High impact polystyrene resin (MIPS resin), styrene-acrylonitrile copolymer (AS resin), styrene-methyl methacrylate copolymer resin, styrene-butadiene-acrylonitrile copolymer resin (ABS) blended with resin and HIPS resin Resin), modified polyphenylene ether resin (modified PPE resin) in which GPPS resin is alloyed with polyphenylene ether, and the like.

  Among the above, the impact-resistant polystyrene resin is particularly excellent in stretchability and flexibility. For this reason, the above-mentioned tensile breaking elongation can be made especially high, and the adhesive sheet 1 for labels becomes the thing by which generation | occurrence | production of the piece of residue was suppressed especially. In addition, the manufactured label can be suitably prevented from being broken when the casing is reused and the label is peeled off. This is because in the impact-resistant polystyrene resin, the particulate rubber component is finely dispersed in the polystyrene, and this particulate rubber component contributes to the improvement of the stretchability and flexibility of the film substrate 11. Conceivable. In particular, among the above-described impact-resistant polystyrene resins, such an effect becomes remarkable when a HIPS resin is used as the polystyrene-based resin.

  When the HIPS resin is included as the polystyrene resin, the content of the HIPS resin in the polystyrene resin is preferably 50 to 98 wt%, and more preferably 65 to 95 wt%. Thereby, while making the hardness of the film base material 11 sufficient, a softness | flexibility and a stretching property can be made especially excellent. As a result, the label pressure-sensitive adhesive sheet 1 is particularly suppressed from being broken. Further, the produced label is particularly excellent in peelability.

  The rubber component contained in the impact-resistant polystyrene resin is not particularly limited. For example, acrylic rubber, acrylonitrile butadiene rubber, isoprene rubber, urethane rubber, ethylene propylene rubber, epichlorohydrin rubber, chloroprene rubber, styrene butadiene rubber, butadiene rubber , Synthetic rubber such as polyisobutylene (butyl rubber) and natural rubber can be used, and one or more of these can be used in combination.

  Among the above, as the rubber component, styrene butadiene rubber or butadiene rubber is preferably used, and styrene butadiene rubber is more preferably used. Thereby, as for the adhesive sheet 1 for labels, the chipping | disconnection is suppressed especially.

  Moreover, when a rubber component contains a styrene butadiene rubber, the copolymerization ratio (styrene: butadiene) of styrene and butadiene which is a monomer component of a styrene butadiene rubber is 30: 70-60: 40 by mass ratio. Is more preferable, and 35:65 to 55:45 is more preferable. Thereby, the softness | flexibility of the film base material 11 shall be made sufficiently excellent, and the chip breakage at the time of the scrap raising of the adhesive sheet 1 for labels can be suppressed especially effectively. Moreover, the film base 11 can have sufficient rigidity, and the workability at the time of sticking and peeling of the label produced from the pressure-sensitive adhesive sheet 1 can be made particularly easy. Moreover, it is suitably prevented that the manufactured label is deteriorated due to environmental changes such as temperature and humidity changes.

  Moreover, it is preferable that it is 20-60 wt%, and, as for content of the rubber component in an impact-resistant polystyrene resin, it is more preferable that it is 30-45 wt%. Thereby, the tear strength of the film base material 11 can be made sufficient. As a result, the label pressure-sensitive adhesive sheet 1 is particularly suppressed from being broken.

  Moreover, it is preferable that content in the polystyrene-type resin in the film base material 11 is 66-100 wt%, and it is more preferable that it is 70-95 wt%. Thereby, the recyclability of the adhesive sheet 1 for labels can be made sufficiently high.

  Moreover, it is preferable that the film base material 11 contains a thermoplastic elastomer. As a result, the film substrate 11 is particularly excellent in stretchability and flexibility, and is particularly excellent in tear strength. As a result, when the residue of the label pressure-sensitive adhesive sheet 1 is raised, the breakage of the residue is particularly suppressed, and the label manufactured using the label pressure-sensitive adhesive sheet 1 is broken when peeled from the casing of the OA device. It will be difficult. Moreover, when manufacturing the film base material 11 by a method as will be described later, it is difficult for the film base material 11 to have defects and the like by using such a material excellent in stretchability and flexibility together with the styrenic resin. Thus, the label pressure-sensitive adhesive sheet 1 is particularly preferably prevented from generating unintentional breaks.

  Examples of the thermoplastic elastomer that can be used for the film substrate 11 include styrene-based, polyolefin-based, polyvinyl chloride-based, polyurethane-based styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block polymers, and the like. , Polyester-based, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, chlorinated polyethylene-based thermoplastic elastomers, and the like. One or more of these can be used in combination. .

  Among the above-mentioned, the thermoplastic elastomer preferably includes a styrene-based thermoplastic elastomer, and more preferably includes a styrene-butadiene-styrene block copolymer. Thereby, the stretchability and flexibility of the film substrate 11 can be made particularly excellent, and the film substrate 11 has particularly excellent tear strength. This is considered because such a thermoplastic elastomer has a high affinity with the styrene resin as described above. In particular, when the film substrate 11 contains HIPS resin and the rubber component of the HIPS resin contains styrene butadiene rubber or butadiene rubber, the affinity between the rubber component of the HIPS resin and the thermoplastic elastomer is particularly excellent. The film substrate 11 has particularly excellent tear strength. In particular, when the film base material 11 is manufactured by a method as described later, the use of such a thermoplastic elastomer together with the styrene resin makes it difficult for the film base material 11 to be particularly defective.

  The content of the thermoplastic elastomer in the film substrate 11 is preferably 3.0 to 35 wt%, and more preferably 5.0 to 30 wt%. Thereby, the flexibility, stretchability, and tear strength of the film substrate 11 can be made particularly excellent, and the rigidity of the film substrate 11 can be made sufficiently high.

  The film base 11 may contain a colorant. As the colorant, various pigments, dyes and the like can be used. In particular, when a pigment is used as the colorant, the label pressure-sensitive adhesive sheet 1 can be colored, and the label pressure-sensitive adhesive sheet 1 can be made opaque. Can be concealed.

  Examples of the pigment include, but are not limited to, kaolin, clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, colloidal silica, and satin. Examples thereof include inorganic pigments such as white and organic pigments such as plastic pigments, and these can be used alone or in combination. Among these, when titanium dioxide is used as a colorant, the label pressure-sensitive adhesive sheet 1 can be made particularly opaque and can be made particularly high in whiteness.

  In such a case, the content of the colorant in the film substrate 11 is preferably 1.5 to 18 wt%, and more preferably 2.7 to 12 wt%. Thereby, the desired color can be more reliably colored while making the tear strength and rigidity of the film substrate 11 sufficiently high.

  The thickness of the film substrate 11 is preferably 50 to 120 μm, more preferably 50 to 100 μm, and still more preferably 55 to 80 μm. Thereby, the pressure-sensitive adhesive sheet 1 for labels has an appropriate rigidity, and the chip breakage is particularly suppressed when the scrap is raised. Moreover, when the label manufactured using the pressure-sensitive adhesive sheet 1 for labeling is attached to a housing such as an OA device, entrainment of bubbles and generation of wrinkles are suitably prevented. Moreover, when winding the manufactured strip-shaped pressure-sensitive adhesive sheet 1 for labels, it is reliably prevented that floating occurs between the pressure-sensitive adhesive and the release sheet.

<Adhesive layer>
The adhesive layer 12 is provided on one surface side of the film substrate 11.

  The pressure-sensitive adhesive layer 12 is mainly composed of a pressure-sensitive adhesive, and a label formed from the pressure-sensitive adhesive sheet 1 for labels can be attached to a housing such as an OA device by the pressure-sensitive adhesive layer 12.

  The pressure-sensitive adhesive that can be used for the pressure-sensitive adhesive layer 12 is not particularly limited, and one or more known pressure-sensitive adhesives can be used in combination. It is preferable to use a mold-type pressure-sensitive adhesive. Thereby, for example, after a label manufactured by the pressure-sensitive adhesive sheet for label 1 is attached to a housing such as an OA device, the label can be easily peeled off. That is, even when the housing such as the OA equipment is reused as it is, the label pressure-sensitive adhesive sheet 1 can be used particularly preferably.

  Although it does not specifically limit as a re-peeling type adhesive, For example, the adhesive etc. which mainly have an acrylic adhesive, a rubber adhesive, a polyester adhesive, or a silicone adhesive are mentioned. Among these, it is preferable to use an acrylic adhesive. The acrylic pressure-sensitive adhesive is excellent in weather resistance and can be obtained at a relatively low cost.

  As the acrylic pressure-sensitive adhesive, it is preferable to use a copolymer obtained by copolymerizing a (meth) acrylic acid alkyl ester monomer and a vinyl monomer. Thereby, the adhesion layer 12 becomes excellent in light resistance, and has moderate adhesive force.

  Moreover, it is preferable that the carbon number of the alkyl group of the (meth) acrylic-acid alkylester monomer which comprises an acrylic adhesive is 4-12. Thereby, the adhesive layer 12 can be easily peeled from the pasted object once attached while having an appropriate adhesive force.

  Examples of the (meth) acrylic acid alkyl ester monomer having 4 to 12 carbon atoms in the alkyl group include butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) ) Acrylate, decyl (meth) acrylate and the like, and one kind or a combination of two or more kinds can be used.

  Specific examples of the vinyl monomer include (meth) acrylic acid alkyl esters having 1 to 3 carbon atoms in the alkyl group; hydroxyl group-containing acrylic acid alkyl esters; (meth) acrylic acid, crotonic acid, maleic acid, and the like. Examples include α, β-unsaturated carboxylic acid; acrylamide; acrylonitrile; styrene; vinyl acetate; vinyl pyrrolidone and the like. By using such a vinyl monomer for an acrylic pressure-sensitive adhesive, it is possible to adjust the adhesive force and cohesive force of the obtained pressure-sensitive adhesive.

  In addition, a copolymer as an acrylic pressure-sensitive adhesive is obtained by copolymerizing a mixture of monomers as described above by a conventionally known method such as a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, or a bulk polymerization method. be able to.

  The pressure-sensitive adhesive may contain a crosslinking agent such as an isocyanate crosslinking agent, an epoxy crosslinking agent, a metal chelate crosslinking agent, or an aziridine crosslinking agent. When a crosslinking agent is blended with the pressure-sensitive adhesive, an isocyanate-based crosslinking agent is particularly preferable.

  Examples of the isocyanate-based crosslinking agent include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, and isophorone diisocyanate. , Cycloaliphatic polyisocyanates such as hydrogenated diphenylmethane diisocyanate and the like, and biurets, isocyanurates, and low molecular activities such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, etc. The adduct body etc. which are a reaction material with a hydrogen containing compound can be mentioned. These crosslinking agents may be used individually by 1 type, and may be used in combination of 2 or more type.

  The blending amount of the crosslinking agent is preferably 0.5 to 5 wt%, particularly preferably 1 to 3.5 wt% with respect to the pressure-sensitive adhesive: 100 wt% in order to obtain the required adhesive properties (all in terms of solid content) value).

  In addition, the adhesive layer 12 may have various known properties such as a tackifier, a filler, an antioxidant, a heat stabilizer, an ultraviolet absorber, a light stabilizer, a colorant, a flame retardant, and an antistatic agent as necessary. Additives may be included.

  The thickness of the adhesive layer 12 is preferably 10 to 50 μm, and more preferably 15 to 40 μm. As a result, the label produced using the pressure-sensitive adhesive sheet 1 has sufficient adhesiveness (tack) and adhesive strength, and the adhesive sticks out at the end of the label at the time of application to the application target. It is possible to prevent dust from adhering to the adhesive that is exposed at the end portion. In addition, when the label is peeled off from the sticking target, the adhesive layer is preferably prevented from causing cohesive failure, and after the label is peeled off, the adhesive is reliably prevented from remaining on the sticking target.

<Peeling sheet>
The release sheet 13 is provided on the surface of the adhesive layer 12 opposite to the film base 11.

  The release sheet 13 is not particularly limited, and generally, a known release sheet in which a release process is performed on one side of the sheet can be appropriately selected and used. Examples of the sheet that can be used for the release sheet 13 include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyolefin films such as polyethylene, polypropylene, and polymethylpentene, clay-coated paper, glassine paper, and recycled paper. Examples thereof include paper base materials such as paper, and sheets such as laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials.

Examples of the release treatment agent for performing the release treatment include silicone resins, long-chain alkyl resins, fluorine resins, and the like.
Although the thickness of the peeling sheet 13 is not specifically limited, It is preferable that it is 10-150 micrometers, and it is preferable that it is 20-130 micrometers.

≪Method for manufacturing label adhesive sheet≫
Next, the manufacturing method of the adhesive sheet for labels of this invention is demonstrated.

  The manufacturing method of the pressure-sensitive adhesive sheet for labels according to the present invention includes a base material forming step of forming a band-shaped film base material made of a polystyrene resin by an inflation method, and an adhesive layer is formed on one surface side of the film base material. An adhesive layer forming step. Thereby, the adhesive sheet 1 for labels as mentioned above can be manufactured easily and reliably.

<Film base material formation process>
First, the strip-shaped film base material 11 comprised with the polystyrene-type resin by the inflation method is formed.

  In the present embodiment, the film substrate 11 is manufactured by an inflation method. By forming the film substrate 11 by the inflation method, the film substrate 11 can surely satisfy the relationship as described above with the tear t in the tear strength test as described above. Moreover, the film base material 11 formed in this way has a tear strength in the width direction and a tear strength in the longitudinal direction sufficiently close to each other. As a result, the label pressure-sensitive adhesive sheet 1 using the film substrate 11 is suitably suppressed from being broken when the residue is raised.

  This is considered as follows. In the inflation method, the film material constituting the film base 11 is extruded in a tube shape in a softened state, and the extruded film material is expanded by applying pressure from the inside of the tube shape with gas or the like to form a cylinder. The film is formed by cooling the cylindrical film. In this way, when the tubular film material becomes a cylindrical film by expanding the resin material with a gas or the like by pressure, the tube material is uniformly formed in any direction parallel to the main surface of the film. The resin is stretched. That is, the formed film base 11 has a particularly low anisotropy with respect to physical properties such as tear strength. For this reason, the film base material 11 is considered to have the physical properties as described above.

  On the other hand, when a film base material is formed without using the inflation method, the effects as described above cannot be obtained. For example, when a film substrate is formed by a general T-die method or the like, anisotropy occurs in the physical properties of the formed film substrate. In particular, the film substrate in this way has a weak tear strength in the longitudinal direction, and the tear t in the tear strength test cannot satisfy the above-described relationship. As a result, the produced pressure-sensitive adhesive sheet for labels has a lot of scraps when scraped.

  Moreover, the film base material 11 formed into a film in this way turns into the longitudinal direction (MD direction), and the 90 degree direction with respect to the film forming direction becomes the width direction (CD direction).

  The film material constituting the film base 11 can be obtained by kneading and mixing the constituent materials of the film base 11 as described above.

  In particular, when the film material includes a thermoplastic elastomer, the film material has a particularly high flexibility, and the formed film base 11 may be partially thinned or have defects (cracks) or the like. Is prevented. Moreover, even when the formed film substrate 11 is relatively thin, the reliable film substrate 11 can be formed more reliably. Such an effect becomes remarkable when a styrene-butadiene-styrene block copolymer is used as the thermoplastic elastomer.

  The film material may be a mixture of all the materials constituting the film substrate 11 at the same time, or a part of the components of the film material to be prepared is mixed in advance to obtain a mixture (master). Thereafter, the mixture (master) may be mixed with other components.

  For example, when the film material contains a colorant, the colorant and a part of the styrenic resin are mixed in advance to obtain a colorant masterbatch, and the colorant masterbatch and other constituent materials are mixed. A film material may be obtained. Thereby, a coloring agent can be mixed in a film material more uniformly, and the obtained film base material 11 becomes what was more uniformly colored in each site | part.

  In particular, when a pigment is used as the colorant, the content of the pigment in the masterbatch of the colorant is preferably 30 to 60 wt%, and more preferably 35 to 55 wt%. As a result, the pigment can be more uniformly dispersed, the formed film base 11 can be uniformly colored, and the occurrence of foreign matter (fish eyes) in which the pigment is aggregated is reliably prevented. The

  Moreover, it is preferable that 5-30 weight part is mixed with respect to the remaining styrene resin: 100 weight part, and, as for the master batch of such a coloring agent, it is more preferable that 10-20 weight part is mixed. Thereby, while being able to color the film base material 11 more reliably, it is prevented suitably that the film base material 11 becomes weak.

  Further, the surface of the film base 11 may be subjected to corona discharge treatment. Thereby, the adhesiveness with an adjacent layer can be made especially excellent, for example, the anchoring (throwing property) of an adhesion layer can be improved. Further, the ink adhesion (acceptability) of the film base 11 can be made particularly excellent.

  The film substrate 11 may be stretched after being formed into a film shape.

<Adhesive layer forming step>
Next, the adhesive layer 12 is formed on one main surface of the film substrate 11.

  The pressure-sensitive adhesive layer 12 is formed by forming a pressure-sensitive adhesive layer (precursor) in the form of a sheet on the release sheet 13, and the pressure-sensitive adhesive layer (precursor) is interposed between the release sheet 13 and the film substrate 11. It can form by pasting together.

  In this way, once the adhesive layer is formed on the release sheet 13 and bonded to the release sheet 13 and the film substrate 11, there is no need to directly apply the constituent material of the adhesive layer to the film substrate 11. It is possible to prevent an organic solvent or the like used in applying the constituent material from being brought into contact with the film substrate 11. That is, it is reliably prevented that the film base material 11 unintentionally comes into contact with the organic solvent and deteriorates.

  The pressure-sensitive adhesive layer (precursor) can be formed, for example, by applying a coating liquid mainly containing a pressure-sensitive adhesive on the release sheet 13 and drying it.

  The coating liquid can be obtained, for example, by dissolving the material constituting the adhesive layer 12 with an organic solvent such as ethyl acetate or toluene.

  Moreover, it is preferable that it is 20-60 wt%, and, as for solid content of a coating liquid, it is more preferable that it is 25-55 wt%. Thereby, an adhesive layer having a more uniform thickness can be formed.

  Application | coating of a coating liquid can be performed with a coating machine (coater), for example. The coating machine that can be used for coating the coating liquid is not particularly limited. For example, an air knife coater, a blade coater, a bar coater, a gravure coater, a roll coater, a curtain coater, a die coater, a knife coater, a screen coater, Mayer bar coaters, kiss coaters and the like.

  Next, the release sheet 13 provided with the adhesive layer (precursor) and the film substrate 11 are bonded together so that the adhesive layer (precursor) is sandwiched between the release sheet 13 and the film substrate 11. As a result, the adhesive layer 12 is formed on the film substrate 11. Thereby, the adhesive sheet 1 for labels is obtained.

≪Label manufacturing method≫
Next, the manufacturing method of the label using the adhesive sheet 1 for labels as mentioned above is demonstrated.

First, printing is performed on the film substrate 11 of the pressure-sensitive adhesive sheet 1 for labels.
Next, by forming a cut on the film substrate 11 of the label pressure-sensitive adhesive sheet 1, the label portion 14 having a shape corresponding to the label and the remaining portion 15 are formed.

  Next, a label in which the label portion 14 remains on the release sheet 13 is obtained by peeling the residue portion 15 from the release sheet 13 (up the residue).

  Separation of the residue portion 15 can be efficiently and continuously performed by performing, for example, a residue raising winder or the like. When the conventional pressure-sensitive adhesive sheet for labels is used, there is a problem in that the residue of the residue is cut off when the residue is raised. In this way, when the scrap breakage occurs frequently, it is necessary to interrupt the scrap lifting every time the scrap breaks, and to prepare for the winding of the scrap lift again, resulting in a problem that the label cannot be produced efficiently. However, the label pressure-sensitive adhesive sheet of the present invention is suitably prevented from being scraped off. For this reason, a label can be produced without interrupting the residue raising operation.

  Alternatively, the label may be directly printed after the label is manufactured, or the label may be manufactured without performing the printing process.

≪Label≫
Next, the label manufactured using the label adhesive sheet as described above will be described.

A label uses the adhesive sheet 1 for labels as mentioned above.
The label may be affixed to any object, but is preferably affixed to OA equipment, home appliances, and the like. Generally, polystyrene-based resins such as polystyrene (PS) and acrylonitrile / butadiene / styrene (ABS) are used for OA equipment and housings for home appliances. Since the label is made of the same type of resin as the casing, it is not necessary to remove the label from the casing when the casing is recycled. That is, when the housing is once softened and remolded, impurities other than the polystyrene resin are less likely to be mixed due to the presence of the label. For this reason, when a label is used, the work at the time of recycling can be simplified.

  Further, as described above, the label is difficult to cut when peeled from these housings. For this reason, when the casing is reused as it is without being recycled, it is necessary to peel the label once, but the label is prevented from partially remaining on the casing and is preferably peeled off. The

  As mentioned above, although this invention was demonstrated about embodiment of illustration, this invention is not limited to this.

For example, the pressure-sensitive adhesive sheet for labels of the present invention may not have a release sheet.
Moreover, for example, an arbitrary layer may be provided in the pressure-sensitive adhesive sheet for labels of the present invention. For example, an intermediate layer may be provided between the adhesive layer and the base film for the purpose of improving adhesion and the like.

  Further, for example, an ink receiving layer may be provided on the main surface of the film base opposite to the adhesive layer. Thereby, the adhesiveness with the ink of the adhesive sheet for labels becomes a particularly excellent thing.

  The ink receiving layer can be composed of a pigment capable of adsorbing ink, a binder resin, and the like.

  As the pigment, known ones can be used, and for example, calcium carbonate, titanium oxide, synthetic silica and the like can be used. Among these, synthetic silica has a high specific surface area and can quickly absorb the liquid component in the ink, so that the image formed by the ink on the ink receiving layer is prevented from bleeding. Further, the ink density of the image can be increased.

  In addition, the binder resin is not particularly limited, but one kind of acrylic resin, polyvinyl alcohol resin, ethylene / vinyl acetate copolymer resin, ethylene / vinyl alcohol copolymer resin, styrene / butadiene copolymer resin or the like is used. Two or more types can be used in combination. Among these, when an acrylic resin is used, the durability and weather resistance of the ink receiving layer can be made particularly excellent.

  The ink receiving layer can be formed, for example, by applying an ink receiving agent in which these materials are dispersed and dissolved in a liquid medium such as an organic solvent to the surface of the film substrate.

  As the liquid medium that can be used for the ink receiving agent, a liquid that does not dissolve the film substrate can be used. For example, a liquid mainly composed of alcohol such as isopropyl alcohol or ethanol can be used.

  Further, the content of the dispersion medium in the ink receiving agent is preferably 60 to 70 wt%. Accordingly, the viscosity of the ink receiving agent can be made sufficiently low while sufficiently including other components in the ink receiving agent, and an ink receiving layer having a more uniform thickness can be formed. .

  The pigment content in the ink receiving agent is preferably 5 to 10 wt%. Further, the content of the binder resin in the ink receiving agent is preferably 20 to 30 wt%.

The ink receiving agent can be applied to the film substrate by using, for example, a knife coater, a gravure coater, a roll coater or the like. The coating amount of the ink receiving agent is a solid weight after drying (as an ink-receiving layer), more be preferably 0.5 to 4.0 g / ^{m 2,} is 2.0 to 3.0 g / ^{m 2} preferable.

  Moreover, in embodiment mentioned above, although the adhesion layer was once formed on the peeling sheet and was provided by bonding together a peeling sheet and the film base material 11, it is not limited to this. For example, the pressure-sensitive adhesive layer may be provided by bonding a pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive on the film base material 11, or a coating liquid as described above is directly applied onto the film base material. It may be provided.

Next, specific examples of the present invention will be described.
1. Manufacture of label adhesive sheets

Example 1
(A) Film substrate forming step First, 60 parts by weight of styrene and 40 parts by weight of styrene butadiene rubber were graft polymerized to prepare an impact resistant polystyrene resin (HIPS resin).

  Next, 7.5 parts by weight of HIPS resin and 7.5 parts by weight of titanium dioxide were mixed to obtain a master batch of a colorant.

  Next, 100 parts by weight of impact-resistant polystyrene resin, 15 parts by weight of a colorant masterbatch, and 18 parts by weight of a styrene-butadiene-styrene block copolymer were mixed to obtain a film material.

Next, the film material was extruded while being melted at 200 ° C. using an inflation film forming machine to obtain an unstretched film having a thickness of 70 μm.
Next, corona discharge treatment was performed on one side of the unstretched film to obtain a film substrate.

(B) Adhesive layer forming step Next, an adhesive ("P-2041" manufactured by Lintec) was applied to a release sheet ("8LK" manufactured by Lintec) coated with a polyethylene compound on polyethylene laminated paper, and 90 An adhesive layer having a dry thickness of 20 μm was formed by drying at 60 ° C. for 60 seconds to obtain a laminate comprising a release sheet and an adhesive layer.

  Next, the adhesive layer is formed on the film substrate by bonding the surface having the adhesive layer of the laminate and the surface of the film substrate on which the corona discharge treatment has been performed, and the film substrate, the adhesive layer, A label pressure-sensitive adhesive sheet having a release sheet was produced.

(Examples 2-5 , 7)
A label pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the type and content of the material used for the film material were changed as shown in Table 1.

(Comparative Example 1)
First, a film material was obtained in the same manner as in Example 1 except that 3 parts by weight of the styrene-butadiene-styrene block copolymer used for the film material was changed.

  Next, the film material was extruded while being melted at 200 ° C. using a T-die extrusion film forming machine, and subjected to a stretching treatment to obtain a stretched film having a thickness of 70 μm.

Next, one side of the obtained stretched film was subjected to corona discharge treatment to obtain a film substrate.
Thereafter, a pressure-sensitive adhesive sheet for labels was produced in the same manner as in Example 1.

(Comparative Example 2)
A label pressure-sensitive adhesive sheet was produced in the same manner as in Comparative Example 1 except that the stretching treatment was not performed during the production of the film substrate.

(Comparative Example 3)
A pressure-sensitive adhesive sheet for labels was produced in the same manner as in Example 1 except that the styrene-butadiene-styrene block copolymer was not used as the film material.

  Table 1 shows the material and content of the film base material used in each example and each comparative example, and the film base film forming method. In the table, “HIPS” indicates HIPS resin, “MIPS” indicates MIPS resin, “SBS” indicates styrene-butadiene-styrene block copolymer, and “SIS” indicates styrene-isoprene. -Represents a styrene block copolymer. As the MIPS resin, a polystyrene resin and a HIPS resin were mixed at a weight ratio of 50:50.

2. Evaluation 2.1 Tear Strength Test About the film base material manufactured in each Example and each Comparative Example, the width direction and the longitudinal direction were torn at a test speed of 200 mm / min in accordance with the trouser method according to JIS K 7128-1. A strength test was performed, and the tear strength per unit thickness was defined as the tear strength.

2.2 Tear Directionality In the tear strength test performed in 2.1, the tear pieces formed after the tear strength test for the test pieces in the width direction of the film bases of each Example and each Comparative Example were as follows. The tear direction was determined as follows. That is, in each test piece, the point B on the tear t shown in FIG. 3 was obtained, and the direction of the straight line connected by the points A-B was taken as the tear direction. Next, scissors BAC was obtained, and the deviation of the tear t from the width direction in the tear direction was evaluated according to the following four-stage criteria.

◎ ... ∠ BAC is 25 ° or less.
○ ∠ BAC is larger than 25 ° and 30 ° or less.
Δ: BAC is greater than 30 ° and less than 35 °.
×: ∠ BAC is greater than 35 °.

2.3 Tensile Breaking Elongation The tensile breaking elongation of each film base material of each example and each comparative example was measured according to ASTM D882.

  About the width direction and longitudinal direction of a base film, the test piece of the film base material punched into the dumbbell shape of width: 10mm and marked line length: 100mm was papered, respectively. Next, using a tensile tester, the test piece was pulled at a speed of 200 mm / min under a temperature of 23 ° C. and a humidity of 50% RH, and the length of the test piece at the time of breaking was measured. The elongation [%] with respect to the length of the piece was determined.

2.4 Scraping property About the pressure-sensitive adhesive label sheet obtained in each example and each comparative example, a label printing machine “LPM-300IT (manufactured by Lintec Corporation)” provided with a die-cutting device and a scrap lifting device is used. Then, label removal was performed with a pattern as shown in FIG. 6 to form a label portion and a residue portion. Thereafter, the residue was raised and the residue was taken up, and the residue was evaluated according to the following four-stage criteria.

A: No residue
○: Scrap breakage occurs once every 20 m or more and less than 200 m.
Δ: Scrap breakage occurs once every 5 m or more and less than 20 m.
X: Scrap breakage occurs at a frequency of less than 5 m.

2.5 Peelability For the pressure-sensitive adhesive sheets for labels of each Example and each Comparative Example, 10 cross-shaped labels as shown in FIG. 7 were prepared. In the figure, the radius of curvature of the corner surrounded by the dotted line was 1.0 mm. After making the label, the label is allowed to stand at room temperature for 24 hours, and then the label is peeled off from the longitudinal direction and the width direction of the original pressure-sensitive adhesive sheet for labeling on the release sheet. Evaluation was made according to criteria.

○: There was no label to be cut.
(Triangle | delta): 1-3 labels cut | disconnected at the time of peeling.
X: Four or more labels were cut at the time of peeling.
These results are shown in Table 2.

As shown in Table 2, the label pressure-sensitive adhesive sheet of each example was suitably prevented from being broken. Further, the label was prevented from being cut even when the label was peeled from the release sheet. That is, it can be said that the label is prevented from being cut when it is peeled off from the housing of the OA device or the like, and it is considered that the OA device or the like can be easily reused.
On the other hand, satisfactory results were not obtained with the pressure-sensitive adhesive sheet for labels of each comparative example.

It is sectional drawing which shows an example of the adhesive sheet for labels of this invention. It is a top view which shows an example of the adhesive sheet for labels of this invention. It is a top view which shows an example of the test piece at the time of performing the tear strength test about the film base material of the adhesive sheet for labels. It is a perspective view which shows the outline of the tear strength test done about the film base material of the adhesive sheet for labels. It is a perspective view which shows a part of label adhesive sheet at the time of residue raising. It is a top view which shows the pattern used for evaluation of the residue raising property of the adhesive sheet for labels. It is a top view which shows the shape of the test piece used for evaluation of peelability of a label.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Label adhesive sheet 11 ... Film base material 11 '... Test piece 111 ... End part 112 ... End part 12 ... Adhesive layer 13 ... Release sheet 14 ... Label portion 15 ... residue portion 151 ... corners 20A, 20B ... gripping tool

Claims (10)

A band-shaped film substrate made of polystyrene-based resin;
Having an adhesive layer provided on one side of the film substrate;
The film base material is torn according to JIS K 7128-1 with respect to the width direction of the film base material (direction of 90 ° with respect to the film forming direction when the film base material is formed). When the strength test is performed, the tear starting point formed on the test piece of the film base, and a distance of 3.0 cm from the start point in the width direction of the film base, longitudinal straight line connecting a point crossing the tear line parallel to (film forming direction when the film substrate is a film) is, to name a width direction and an angle of less than ± 30 ° of the substrate,
The film substrate has a tear strength of 1500 mN / mm or more when the tear strength test is performed in the longitudinal direction.
The tear strength when the tear strength test is performed with respect to the width direction is 1500 mN / mm or more,
When the film substrate is subjected to the tear strength test in the longitudinal direction and the width direction, the ratio of the tear strength in the longitudinal direction to the tear strength in the width direction is 0.70. 1.30,
The film substrate has a tensile elongation at break of 80% or more as measured in accordance with ASTM D882 for the longitudinal direction,
A pressure-sensitive adhesive sheet for labels, wherein the tensile breaking elongation measured according to ASTM D 882 in the width direction is 80% or more . The pressure-sensitive adhesive sheet for labels according to claim 1 , wherein the film substrate is an unstretched film . The pressure-sensitive adhesive sheet for labels according to claim 1 or 2 , wherein the polystyrene-based resin contains an impact-resistant polystyrene resin.   The pressure-sensitive adhesive sheet for labels according to claim 3, wherein the rubber component of the impact-resistant polystyrene resin is styrene-butadiene rubber.   The pressure-sensitive adhesive sheet for labels according to claim 4, wherein a copolymerization ratio of styrene and butadiene (styrene: butadiene), which is a monomer component of the styrene-butadiene rubber, is 30:70 to 60:40 in terms of mass ratio.   The pressure-sensitive adhesive sheet for labels according to claim 4 or 5, wherein the content of the styrene-butadiene rubber in the impact-resistant polystyrene resin is 20 to 60 wt%.   The film substrate includes a thermoplastic elastomer,
  The pressure-sensitive adhesive sheet for labels according to any one of claims 1 to 6, wherein a content of the thermoplastic elastomer in the film base is 5.0 to 30 wt%.   The pressure-sensitive adhesive sheet for labels according to claim 7, wherein the thermoplastic elastomer contains a styrene-butadiene-styrene block copolymer. A base material forming step of forming a band-shaped film base material composed of a polystyrene-based resin by an inflation method;
Having an adhesive layer forming step of forming an adhesive layer on one side of the film substrate;
The film substrate was subjected to a tear strength test performed in accordance with JIS K 7128-1 with respect to the width direction of the film substrate (90 ° direction with respect to the film forming direction of the film substrate). The starting point of the tear formed on the test piece of the film base, and a distance of 3.0 cm from the start point in the width direction of the film base, the longitudinal direction of the film base (the film base line film forming direction) in a straight line parallel of wood is connecting the point of intersection in tearing the can, to name a width direction and an angle of less than ± 30 ° of the substrate,
The film substrate has a tear strength of 1500 mN / mm or more when the tear strength test is performed in the longitudinal direction.
The tear strength when the tear strength test is performed with respect to the width direction is 1500 mN / mm or more,
When the film substrate is subjected to the tear strength test in the longitudinal direction and the width direction, the ratio of the tear strength in the longitudinal direction to the tear strength in the width direction is 0.70. 1.30,
The film substrate has a tensile elongation at break of 80% or more as measured in accordance with ASTM D882 for the longitudinal direction,
A method for producing a pressure-sensitive adhesive sheet for labels, wherein the tensile breaking elongation measured according to ASTM D 882 in the width direction is 80% or more . A label produced by the pressure-sensitive adhesive sheet for labels according to any one of claims 1 to 8 .

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