JP5529446B2 - Thermal adhesive release film and packaging material - Google Patents

Description

  The present invention relates to a heat-adhesive release film and a packaging material, and more particularly, to a heat-adhesive release film and a packaging material that impart releasability only to a necessary portion of a member such as a sanitary napkin.

  In an application in which a member is attached to some target material with an adhesive material, the adhesive material is generally covered with a release film until it is attached.

  For example, in Patent Documents 1 to 3, the inner surface of an individual packaging bag for packaging a sanitary napkin is covered with a release material component such as silicone in order to protect the adhesive material used when fixing the sanitary napkin to shorts or the like. The configuration to be shown is shown. Moreover, in patent documents 1-3, the coating | cover of the individual packaging bag inner surface by a release material component apply | coats a release material component with respect to the individual packaging bag inner surface, or the release paper which performed the peeling process is hot melt etc. This is done by fixing with an adhesive.

  However, when the release material component is applied to the inner surface of the individual packaging bag such as a nonwoven fabric, there is a disadvantage that the applied release material component is easily peeled off from the inner surface of the individual packaging bag. As a method for eliminating this drawback, there is a method in which a polyethylene layer or the like is provided on the entire surface using an extrusion lamination method on one side of the nonwoven fabric, and a release material component is applied on the polyethylene layer. Have.

  Furthermore, when the release paper that has been subjected to the release treatment is fixed to the inner surface of the individual packaging bag with an adhesive such as hot melt, if the release paper is formed of paper, it is stiff and uncomfortable, the finished product tends to be bulky, etc. As a product, it is generally in an unfavorable form. In particular, when a sanitary napkin packaged in an individual packaging bag is carried in a pocket of clothing or the like, discomfort due to the above-described drawbacks becomes significant. On the other hand, when the release paper is formed of a polyethylene film or the like and is similarly fixed by an adhesive such as hot melt, the heat resistance is low, and thus there is a drawback that deformation such as shrinkage is likely to occur when hot melt bonding is performed. In addition, there are cost problems such as the cost of the hot melt adhesive, and processing problems such as a reduction in production speed due to the handling of the hot melt adhesive.

  In addition, Patent Document 1 shows a configuration in which the entire inner surface of the individual packaging bag is covered with a release material component. In this case, a release material component such as silicone is applied to a portion of the napkin where the adhesive material does not contact. It will be coated and is expensive. In addition, when the end portion is sealed with a heat seal, the release material component hinders the heat seal, and has a drawback that a sealing failure is likely to occur.

  The above-mentioned problem of the cost of the release material component can be reduced by applying the coating with the release material component only to a necessary portion of the inner surface of the individual packaging bag, as shown in Patent Documents 2-3. However, when the release material component is applied to the inner surface of the individual packaging bag, the disadvantage that the applied release material component is easily peeled off from the inner surface of the individual packaging bag is increased as compared with Patent Document 1. In addition, when fixing the release paper that has been subjected to the release treatment to the inner surface of the individual packaging bag with an adhesive such as hot melt, there is a problem that when the sanitary napkin is taken out, the individual packaging bag is distorted and difficult to take out. Have.

JP-A-8-324635 JP-A-6-178794 Japanese Patent Laid-Open No. 10-127688

  An object of the present invention is, for example, when obtaining a packaging material for individually packaging an absorbent article, thermal bonding that gives a peeling function to an adhesive material only in a necessary portion of the base material without impairing the productivity of processing. Providing a release film.

  Another object of the present invention is to provide a wrapping material for individually wrapping a supple absorbent article using the heat-adhesive release film and suppressing a feeling of tingling.

  Furthermore, the other subject of this invention becomes clear by the following description.

  The above problems are solved by the following inventions.

(Claim 1)
At least the heat-bonding layer, a protective layer made of synthetic resin, and sequentially have a release layer,
The thermal adhesive layer is formed by combining any one or two or more of the following (A) to (C):
A heat-adhesive release film , wherein the heat-adhesive layer is thermally bonded to an inner surface of a packaging material for individually packaging absorbent articles .
(A) Ethylene / α-olefin copolymer polymerized using a single site catalyst
(B) Ethylene / vinyl acetate copolymer
(C) Ethylene / (meth) acrylic acid ester copolymer

(Claim 2 )
Thermoadhesive release film according to claim 1, wherein the synthetic resin for forming the protective layer made of the synthetic resin is polypropylene and / or propylene · alpha-olefin copolymer.

(Claim 3 )
Thermoadhesive release film according to claim 1 or 2, characterized in that an intermediate layer mainly composed of polyethylene between the protective layer comprising the synthetic resin and the heat-bonding layer.

(Claim 4 )
A packaging material for individually packaging an absorbent article, wherein the thermal adhesive release film according to any one of claims 1 to 3 is provided on the inner surface of the packaging material by thermally bonding the thermal adhesive layer. Packaging material.

(Claim 5 )
The packaging material according to claim 4 , wherein the material is a non-woven fabric.

  By using the heat-adhesive release film of the present invention, while suppressing problems such as impairing the tactile sensation of the product, it does not impair the productivity of processing, and has a peeling function for the adhesive material only on the necessary part of the base material. The packaging material that can be applied and individually wraps the absorbent article obtained using the heat-adhesive release film does not have a paper release paper, and thus has a supple texture that suppresses the feeling of wrinkle. I can do it.

Sectional drawing of the heat bondable peeling film which concerns on one Embodiment of this invention. The perspective view which shows an example of the state which the packaging material which has the thermoadhesive peeling film of this invention packaged the absorbent article

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a thermal adhesive release film according to an embodiment of the present invention. In FIG. 1, 1 is a heat-adhesive release film, and 2 is a base material provided with a heat-adhesive release film 1. The thermal adhesive release film 1 includes a thermal adhesive layer 11, an intermediate layer 12, a protective layer 13, and a release layer 14. The intermediate layer 12 can be provided as necessary for the purpose of imparting molding stability during film molding.

  There is no restriction | limiting in particular as the base material 2 which comprises the heat bondable peeling film 1 of this invention, Plastic films, such as a nonwoven fabric, paper, a metal, PET, and OPP, etc. can be used. When the heat-adhesive release film 1 is provided on a non-woven fabric, it is particularly suitable because the effect of not impairing the texture of the non-woven fabric can be exhibited as compared with a case where a paper release paper is attached to the non-woven fabric with an adhesive. is there. Moreover, it is preferable that the base material 2 is a packaging material for individually packaging an absorbent article such as a sanitary napkin as a product.

  The thermal adhesive layer 11 of the present invention exhibits adhesiveness to the base material 2 by thermocompression bonding.

There is no particular limitation as long as thermal adhesiveness to the base material 2 can be expressed by thermal adhesion processing that is solid at room temperature and is lower than the melting point of the protective layer 13 made of synthetic resin, but any of the following (A) to (C) When one type or two or more types are used in combination, the function is suitably expressed.
(A) Ethylene / α-olefin copolymer polymerized using a single site catalyst (B) Ethylene / vinyl acetate copolymer (C) Ethylene / (meth) acrylic acid ester copolymer

  In addition, it is also preferable to increase the polarity of the surface by applying a corona treatment to the surface of the thermal bonding layer 11 to improve the adhesion to the base material 2.

  (A) The ethylene / α-olefin copolymer constituting the thermal adhesive layer 11 of the heat-adhesive release film 1 of the present invention includes ethylene polymerized using a single site catalyst and an α-olefin having 3 to 12 carbon atoms. And a copolymer thereof.

  The single-site catalyst refers to a catalyst constituted by substantially homogeneous polymerization active sites. Specifically, a metallocene-based transition metal compound (so-called Kaminsky catalyst) or a non-metallocene-based transition metal compound ( A polymerization catalyst comprising a Brookhart catalyst, a phenoxyimine complex, etc.) and a cocatalyst (methylaluminoxane, boron compound, etc.) can be used. As the most preferable single site catalyst, a metallocene catalyst having a metallocene-based transition metal compound as a main component can be exemplified. As the metallocene catalyst, a non-bridged metallocene catalyst such as biscyclopentadienylzirconium dichloride or a substituted product thereof can also be used.

  The α-olefin of the ethylene / α-olefin copolymer used in the present invention is preferably an α-olefin having 3 to 12 carbon atoms. Specific examples include propylene, 1-butene, 1-pentene, 1-hexene and 1-octene. The content of α-olefin in the ethylene / α-olefin copolymer is preferably 5 to 40% by weight, more preferably 7 to 35% by weight. When the α-olefin content is low, the impact strength and low-temperature heat sealability of the film cannot be obtained, and when it is too high, the blocking resistance is impaired. The α-olefin content is measured by 13C-NMR method.

  Polymerization using a single site catalyst for obtaining an ethylene / α-olefin copolymer can be performed by the same method as described in the section of the propylene / α-olefin copolymer of the protective layer 13.

  The metallocene ethylene / α-olefin copolymer may be appropriately selected from those commercially available as metallocene polyethylene. Examples of commercial products include “Kernel” and “Harmolex” manufactured by Nippon Polyethylene, and “Affinity” manufactured by DuPont Dow. The ethylene / α-olefin copolymer may be used singly or as a mixture of two or more thereof, and blending with other polyethylene, particularly high-pressure low-density polyethylene is also a preferred embodiment.

  The ethylene / α-olefin copolymer used in the present invention is preferably a copolymer satisfying the following characteristics.

  MFR (190 ° C, 21.18N load), when producing a packaging material that individually wraps absorbent articles by thermal bonding with a nonwoven fabric or the like, the larger one bites into the gap between the fibers of the nonwoven fabric during thermal bonding. In view of the advantages such as high adhesion, it is preferable, specifically 0.1 g / 10 min or more is preferable, 1 g / 10 min or more is more preferable, and 4 g / 10 min is sufficient. It is particularly preferable because it bites in. Further, a smaller value is preferable because the film forming processability is stable. Specifically, 20 g / 10 min or less is preferable, 15 g / 10 min or less is more preferable, and 10 g / 10 min or less is workability. Is particularly preferred since it is stable. In addition, the measurement of MFR is performed based on JIS-K6921-2: 1997 appendix (190 degreeC, 21.18N load).

The density of the ethylene / α-ethylene copolymer used in the present invention is not particularly limited. It is preferable because it has the advantage that it can be used and high adhesion can be obtained. Specifically, 0.925 g / cm ³ or less is preferable, 0.915 g / cm ³ or less is more preferable, and 0.905 g / cm ³ is more preferable. If it is cm ³ or less, sufficient thermal bonding can be obtained even by low-temperature thermal bonding, which is particularly preferable. Also, better to some extent higher, preferably it is possible to suppress the processability problems due to blocking, preferably 0.870 g / cm ³ or more in particular, more preferably as long as 0.880 g / cm ³ or more, 0.885 g / cm Since it can process suitably if it is ³ or more, it is especially preferable. In addition, a density is measured based on the case of the low density polyethylene of JIS-K6922-2: 1997 appendix (23 degreeC).

  The resin component constituting the ethylene / α-olefin copolymer of the present invention can be blended with other additional optional components as long as the effects of the present invention are not significantly impaired. Examples of such optional components include antioxidants, crystal nucleating agents, clearing agents, lubricants, antiblocking agents, antistatic agents, antifogging agents, neutralizing agents, and metal inertness used in ordinary polyolefin resin materials. Agents, fluorescent whitening agents, and the like.

  The thermal adhesive layer 11 of the thermal adhesive release film 1 of the present invention can use (B) an ethylene / vinyl acetate copolymer, and the ethylene / vinyl acetate copolymer can be a tubular system. An autoclave method may be used.

  The vinyl acetate content of the ethylene / vinyl acetate copolymer is higher when manufacturing a packaging material for individual packaging of absorbent articles by thermal bonding with a non-woven fabric, etc. It is preferable because it provides advantages such as adhesion. Specifically, it is preferably 3% by weight or more, more preferably 5% by weight or more, and if it is 7% by weight or more, sufficient thermal bonding is possible even at low temperature thermal bonding. Is particularly preferable. Further, it is preferable that the amount is small to some extent, since workability problems due to blocking can be suppressed. Specifically, it is preferably 30% by weight or less, more preferably 25% by weight or less, and preferably 20% by weight or less. Therefore, it is particularly preferable.

  The MFR (190 ° C, 21.18N load) of the ethylene / vinyl acetate copolymer has a somewhat larger thermal bond when manufacturing a packaging material that individually wraps absorbent articles by thermal bonding with non-woven fabrics. It is preferable because it sometimes shows an advantage that it can bite into the gaps between the fibers of the nonwoven fabric to obtain high adhesion. Specifically, it is preferably 1 g / 10 min or more, more preferably 2 g / 10 min or more, and more preferably 4 g / 10. Minutes are particularly preferable because they can be sufficiently consumed. Further, a smaller value is preferable because the film forming processability is stable. Specifically, 20 g / 10 min or less is preferable, 15 g / 10 min or less is more preferable, and 10 g / 10 min or less is workability. Is particularly preferred since it is stable.

  For the thermal adhesive layer 11 of the thermal adhesive release film 1 of the present invention, (C) ethylene / (meth) acrylic ester copolymer (EEA) can also be used.

  The ethylene / (meth) acrylic acid ester copolymer (EEA) is a copolymer having ethylene and acrylic acid, methacrylic acid, acrylic acid ester and / or methacrylic acid ester as a copolymerization component. As a copolymerization ratio, the (meth) acrylic acid comonomer is preferably 5% by weight to less than 50% by weight, more preferably 10 to 40% by weight, and further preferably 15 to 40% by weight. If it is less than 5%, sufficient adhesive strength cannot be obtained, and if it exceeds 50%, handling as a resin tends to be difficult.

  The thermal adhesive layer 11 of the present invention has a corona treatment on the surface, so that the adhesive strength is improved and integrated in a packaging material for individually packaging absorbent articles obtained by thermal adhesion to a nonwoven fabric or the like. It is possible to provide a packaging material for individually packaging good absorbent articles.

  As conditions for the corona treatment, the wetting tension according to JIS K 6768 is preferably 36 mN / m or more, more preferably 38 mN / m or more, and 40 mN / m or more, so that sufficient adhesion can be easily obtained. This is particularly preferable.

  In this invention, the intermediate | middle layer 12 can also be provided as needed, such as processing stability provision at the time of film forming.

  Further, the intermediate layer 12 of the present invention is not particularly limited because it is provided as necessary, but preferred is a polyolefin-based material, specifically polyethylene, polypropylene, other than ethylene and ethylene. Copolymers with other α-olefins can be used. As the α-olefin, an olefin having about 3 to 12 carbon atoms such as propylene, 1-butene, 1-hexene and 1-octene can be used, and the copolymerization amount is 0 to 30% by weight, preferably 0 to 0% by weight. About 20% by weight. Therefore, linear low density polyethylene is also a preferred material. An ethylene / α-olefin copolymer polymerized using the single site catalyst (A) is also a preferred material. However, it is preferable to use a material having less α-olefin content than the ethylene / α-olefin copolymer of the heat bonding layer 11, and more preferable is to use a high-pressure radical polymerization method low density polyethylene and a single site catalyst. Polymerized ethylene / α-olefin copolymer, linear low density polyethylene, polypropylene or a mixture thereof.

  Furthermore, other thermoplastic resins can be added to the intermediate layer 12 of the present invention.

  The protective layer 13 made of a synthetic resin of the heat-adhesive release film of the present invention is for imparting performance such as waist and heat resistance during heat-adhesion processing as a film for processing, and by using a synthetic resin The processability and the supple feeling of a packaging material for individually packaging an absorbent article obtained by thermal bonding with a nonwoven fabric or the like can be achieved, which is preferable. In particular, when polyolefin is selected, the absorbent article is particularly flexible, and when the following polypropylene and / or propylene / α-olefin copolymer is selected, the flexibility of the packaging material for individually packaging the absorbent article is maintained. This is particularly preferable because the heat resistance necessary for the heat bonding process can be sufficiently achieved.

  As the propylene / α-olefin copolymer used in the present invention, a random copolymer of propylene and an α-olefin other than propylene whose main component is a structural unit derived from propylene is used. The α-olefin used as a comonomer is preferably ethylene or an α-olefin having 4 to 18 carbon atoms. Specifically, ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4,4-dimethylpentene- 1 etc. can be mentioned.

  The amount of α-olefin units in the propylene / α-olefin copolymer is usually 0.5 to 12% by weight, preferably 1 to 10% by weight. When there are many α-olefin units, the rigidity of the film is reduced and the film is easily scratched, and when it is too small, the flexibility and transparency are impaired. Propylene units and α-olefin units can be measured by 13C-NMR method.

  The propylene / α-olefin copolymer used in the present invention is obtained by a single site catalyst. The single-site catalyst refers to a catalyst constituted by substantially homogeneous polymerization active sites. Specifically, a metallocene-based transition metal compound (so-called Kaminsky catalyst) or a non-metallocene-based transition metal compound ( A polymerization catalyst comprising a Brookhart catalyst, a phenoxyimine complex, etc.) and a cocatalyst (methylaluminoxane, boron compound, etc.) can be used. As the most preferable single site catalyst, a metallocene catalyst having a metallocene-based transition metal compound as a main component can be exemplified. The metallocene catalyst includes a transition metal compound of Group 4 of the periodic table containing a ligand having a cyclopentadienyl skeleton (so-called metallocene compound), a cocatalyst that can react with the metallocene compound and be activated to a stable ionic state, A catalyst comprising an organoaluminum compound added if necessary is used.

  The metallocene compound is preferably a bridged metallocene compound capable of stereoregular polymerization of propylene, and more preferably a bridged metallocene compound capable of isoregular polymerization of propylene. Specifically, alkylene biscyclopentadienyl zirconium dichloride, or a substituted product thereof such as methylene biscyclopentadienyl zirconium dichloride, ethylene bis (2-alkylindenyl) zirconium dichloride, ethylene 1,2- (4-phenyl). Indenyl) (2-methyl-4-phenyl-4Hazurenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (fluorenyl) zirconium dichloride, dimethylsilylene (2-methyl-4-t-butyl-cyclopentadienyl) (3′-t-butyl-5′-methyl-cyclopentadienyl) zirconium dichloride, dimethylsilylene (fluorenyl) t-butylamidozirconium dichloride, dimethylsilylenebis [1- (2-methyl-4 Phenyl -4H- azulenyl)] zirconium compounds such as zirconium dichloride can be exemplified. Also, compounds in which zirconium is replaced with titanium or hafnium can be used in the same manner, and chlorides are other halogen compounds, hydrocarbon groups such as methyl, isobutyl, and benzyl, amide groups such as dimethylamide and diethylamide, methoxy groups, phenoxy groups, etc. Can be replaced with an alkoxide group, a hydride group, or the like.

  Co-catalysts that can react with metallocene compounds to be activated to a stable ionic state include organoaluminum oxy compounds (eg, aluminoxane compounds), ion-exchange layered silicates, Lewis acids, boron-containing compounds, ionic compounds, fluorine-containing An organic compound etc. are mentioned.

  Examples of the organoaluminum compound include trialkylaluminum such as triethylaluminum, triisopropylaluminum, and triisobutylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, alkylaluminum dihalide, alkylaluminum hydride, and organoaluminum alkoxide.

  Examples of the polymerization method include a slurry method using an inert solvent in the presence of the catalyst, a solution method, a gas phase method substantially using no solvent, or a bulk polymerization method using a polymerization monomer as a solvent. It is done.

  As the propylene / α-olefin copolymer obtained by the single site catalyst, a commercially available one can be used. For example, a propylene-ethylene random copolymer manufactured by Nippon Polypro Co., Ltd., trade name “Wintech” ( Wintech is a registered trademark of Nippon Polypro Co., Ltd.).

  The propylene / α-olefin copolymer used in the present invention preferably has the following characteristics.

  The MFR (230 ° C., 21.18 N load) of the propylene / α-olefin copolymer is 1 to 20 g / 10 minutes, preferably 2 to 20 g / 10 minutes. The measurement of MFR is performed according to JIS-K6921-2: 1997 appendix (230 degreeC, 21.18N load).

  The propylene / α-olefin copolymer used in the present invention has a melting peak temperature (Tm) measured by a differential scanning calorimeter (DSC) of 120 to 165 ° C, preferably 130 to 150 ° C. When Tm is less than the above range, the rigidity tends to be lowered, and it is difficult to obtain suitable blocking resistance, and when it exceeds the above range, flexibility tends to be impaired.

  The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the propylene / α-olefin copolymer used in the present invention is 1.5 to 3.5, more preferably 1.8. ~ 3.3. Mw / Mn can be measured by gel permeation chromatography (GPC).

  In the propylene / α-olefin copolymer, it is preferable to add a nucleating agent such as a dibenzylidene sorbitol derivative, an organic phosphoric acid metal salt, an organic carboxylic acid metal salt, or a high-density polyethylene to the above-mentioned components. Transparency can be improved. The addition amount is 0.001 to 5% by weight, preferably about 0.01 to 3% by weight. High density polyethylene can simultaneously improve processing stability by addition.

  In order to improve the gloss by adding a nucleating agent in forming a polypropylene film by the biaxial stretching film forming method, the gloss is generally expressed in the biaxial stretching film forming process. Therefore, even if a nucleating agent was further added, the glossiness beyond that was only slight. Glossiness can be remarkably improved by adding a nucleating agent to the propylene / α-olefin copolymer obtained by a single site catalyst. This is a molding method in which inflation molding is slow cooling due to cooling and solidification with air, and spherulites may grow and hinder the appearance of gloss. This is considered to be more remarkable with a propylene / α-olefin copolymer using a single site catalyst.

  The propylene / α-olefin copolymer of the present invention can be blended with other additional optional components as long as the effects of the present invention are not significantly impaired. Examples of such optional components include antioxidants, clarifying agents, lubricants, antiblocking agents, antistatic agents, antifogging agents, neutralizing agents, metal deactivators, and colorants used in ordinary polyolefin resin materials. And a fluorescent brightening agent.

  The additive is blended as needed at any stage of preparing the resin composition. For melt kneading, for example, each component in the form of powder, pellets, etc. is mixed with a uniaxial or biaxial extruder, Banbury mixer, kneader blender, Brabender plastograph, small batch mixer, continuous mixer, mixing roll, etc. Done using. The kneading temperature is generally 180 to 270 ° C.

  In the present invention, since the release layer 14 is provided on the surface of the protective layer 13 made of a synthetic resin by silicone coating or the like, it is preferable to perform corona treatment as described later.

  As conditions for the corona treatment, the wetting tension according to JIS K 6768 is preferably 36 mN / m or more, more preferably 38 mN / m or more, and further preferably 40 mN / m or more.

  In addition, since the corona treatment is also applied to the surface of the thermal adhesive layer 11 as necessary, it becomes a double-sided corona treatment as a film, and may cause problems such as blocking. You can also

  As a technique to increase the surface roughness, high density polyethylene is added to form a sea-island structure, and the surface is roughened by dispersion of the islands, an antiblocking agent is added, and a mat-like roll is used to nip and form physical irregularities. Can be raised.

  The release layer 14 used in the present invention imparts releasability to the adhesive material and can be formed by a known technique such as silicone coating.

  Although there is no restriction | limiting in particular in the manufacturing method of the thermoadhesive peeling film of this invention, The thermal adhesive layer 11, the protective layer 13 which consists of synthetic resins, and the intermediate | middle layer 12 which it comprises as needed are a some extruder and coextrusion. A production method in which a co-extruded film is prepared by inflation molding using a multilayer die or T-die molding, and then the release layer 14 is provided by coating is suitable.

  As an inflation molding method in the present invention, a propylene / α-olefin copolymer constituting the protective layer 13 made of a synthetic resin, and (A) an ethylene / α-olefin copolymer constituting the thermal adhesive layer 11 (B ) Co-extrusion multilayer with ethylene / vinyl acetate copolymer or (C) ethylene / (meth) acrylic ester copolymer as the intermediate layer made of thermoplastic resin mainly composed of ethylene constituting the intermediate layer 12 After being melted by a plurality of extruders with an annular die and extruded into a tube shape, air supplied from a blower or the like is blown from the air cooling ring to the melting tube to be cooled and solidified, and then folded with a pinch roll through a guide plate, It can obtain by the method of taking over with a take-up machine.

  The protective layer 13, the intermediate layer 12, and the thermal bonding layer 11 can be formed with any side as the outside of the tube, but the protective layer 13 is preferably outside.

  The thickness ratio is in the range of protective layer 13: intermediate layer 12: thermal adhesive layer 11 = 5-15: 5-15: 5-15, preferably 10-15: 5-10: 5-10. Is common.

  As a molding machine, a cooling ring, a blower, a guide plate, a pinch roll, and a film take-up machine that can be used in this molding method, those generally used can be used.

  The conditions for molding the heat-adhesive release film in the present invention are not particularly limited as long as the characteristics specified in the present invention are obtained, but the molding temperature is 170 to 250 ° C, preferably 170 to 200 ° C, and the molding speed is 10 to 10. 300 m / min, preferably 50 to 200 m / min is suitable.

  The surface of the protective layer 13 made of synthetic resin is preferably subjected to corona treatment for forming the release layer 14.

  The surface of the thermal adhesive layer 11 can also be subjected to corona treatment for enhancing the thermal adhesive function.

  A release layer 14 made of a synthetic resin is provided on the surface of the protective layer 13 of the coextruded film thus obtained.

  An ordinary gravure coater can be used to coat the surface with ultraviolet curable silicone, dry the solvent in a drying path, and then irradiate with ultraviolet rays to cure the silicone.

  The heat-adhesive release film of the present invention is characterized in that it can be suitably bonded to a certain base material by thermal processing without using an adhesive or the like on part or the entire surface of the base material.

  Since the base material should be selected according to the purpose, there is no particular limitation. However, the base material can be particularly suitably used as a packaging material for individually packaging the absorbent article.

  Although the material should be selected according to the purpose, the nonwoven fabric and the like can be particularly preferably selected.

  In the present invention, the heat-adhesive release film can be provided on the base material by heat-bonding so that the heat-adhesive release film is attached only to a necessary portion of the target material (absorbent article or the like). Hereinafter, the processing provided for individual packaging of sanitary napkins will be described as an example.

  For example, the individual wrapping bag is a non-woven fabric having a length of 250 mm and a width of 150 mm, and the portion of the sanitary napkin adhesive material is 50 mm. The thermoadhesive release film prepared by the manufacturing method described above is slit to a width of 50 mm. Similarly, the non-woven fabric is prepared by slitting to a width of 150 mm, and the both are drawn out so that the surface of the heat-bonding layer 11 faces the non-woven fabric, and is thermally bonded by nipping with a rubber roll facing the metal heat roll. I can do it.

  The temperature of the heat roll is not particularly limited as long as thermal adhesion is expressed, but if it is too low, thermal adhesion is not expressed, so 80 ° C or higher is preferable, 90 ° C or higher is more preferable, and 100 ° C or higher is sufficient. It is particularly preferable because it can be expected to have a good adhesion. Moreover, since the film may be deformed or damaged when the temperature is too high, it is preferably 150 ° C. or lower, more preferably 140 ° C. or lower, and particularly preferably 130 ° C. or lower.

  The packaging material that individually wraps the absorbent article thus obtained has the entire surface of the heat-adhesive release film bonded to the nonwoven fabric, so that it follows the nonwoven fabric that becomes the fabric, is supple, and deforms and becomes difficult to handle. There are no problems such as.

  FIG. 2 is a perspective view showing an example of a state in which an absorbent article is packaged by a packaging material having the heat-adhesive release film of the present invention.

  In FIG. 2, the absorbent article 3 has an adhesive layer 4, and when the packaging material 2 wraps the absorbent article 3 to form an individual packaging structure, the heat-adhesive release film provided on the inner surface of the packaging material 2. 1 is stuck to the adhesion layer 4, and the adhesion layer 4 is protected by this. And in use, the thermoadhesive peeling film 1 stuck to the adhesion layer 4 is peeled from the adhesion layer 4 by opening the packaging material 2.

  EXAMPLES Hereinafter, the present invention will be specifically described according to examples, but the present invention is not limited to these examples. The resins used in the examples are as follows.

<Used resin and molding machine>
(1) Resin thermal adhesive layer:
KF360T: product name kernel (ethylene / α-olefin copolymer by single site catalyst) manufactured by Nippon Polyethylene Co., Ltd. MFR = 3.5 g / 10 min, density = 0.898 g / cm ³
Novatec LV570: Ethylene / vinyl acetate copolymer (EVA) MFR = 15 g / 10 min, manufactured by Nippon Polyethylene Co., Ltd., vinyl acetate (VA) content: 20% by weight
NUC-6225: Nippon Unicar Co., Ltd. ethylene ethyl acrylate copolymer (EEA) MFR = 5 g / 10 min, ethyl acrylate (EA) content: 13% by weight
Middle layer:
WFX4: Nippon Polypro Co., Ltd. trade name Wintech MFR = 7 g / 10 min, density = 0.90 g / cm ³ , melting point = 125 ° C.
Protective layer:
WXK1275: Nippon Polypro's trade name Wintec (a propylene / α-olefin copolymer with a single site catalyst) MFR = 1.5 g / 10 min, density = 0.90 g / cm ³ , melting point = 153 ° C.
HY430 (added only in Example 2): trade name Novatec HD (high density polyethylene) MFR = 0.8 g / 10 min, density = 0.954 g / cm ³ , melting point = 134 ° C., manufactured by Nippon Polyethylene
NA11 (core material): ADEKA company manufactured core material name ADK STAB NA (sodium-2,2′-methylene-bis- (4,6-di-t-butylphenyl) phosphate)

(2) T-die three-layer coextrusion molding machine Made by Plako: Three-kind three-layer T-die coextrusion molding machine Extruder diameter: φ40 mm
Dice: 3 types, 3 layers, multi-manifold die width: 500mm
Extruder set temperature: 200-230 ° C
Die set temperature: 230 ° C

<Evaluation method>
The obtained individual packaging structure was used by a monitor woman and evaluated according to the following criteria.
(Feeling supple)
a: supple, b: supple, c: neutral, d: slightly irritating, e: irritating (ease of taking out napkin)
a: easy to remove, b: slightly easy to remove, c: neutral, d: slightly difficult to remove, e: difficult to remove (sound when removed)
a: The sound is small and I don't care. b: The sound is small and I don't care much. c: Neutral. (Overall evaluation)
a: Like, b: Somewhat like, c: Neutral, d: Somewhat disliked, e: Disliked

  In the evaluation, samples were given to 20 women, and the closest term was selected as sensitivity, and the number is shown in Table 2.

Example 1
The thermal adhesive layer 11 and the protective layer 13 made of a synthetic resin were formed by a T-die coextrusion molding machine with the composition and layer ratio shown in Table 1 with the thermal adhesive layer 11 as the casting roll side. At that time, the extrusion rate is 40 kg / h, the film width is 400 mm, the layer ratio is adjusted to a total thickness of 25 μm, the corona treatment is performed on both sides inline, the ear is cut off by the inline slit, and the final product is 350 mm wide film. Got the product. The corona treatment was performed under the condition that the wetting tension according to JIS K 6768 was 42 mN / m.

  Next, a silicone coat was applied to the surface of the protective layer 13 made of a synthetic resin of the obtained laminated film.

  Further, a non-woven fabric was prepared, and the above heat-adhesive film was superposed on the center of the non-woven fabric so that the heat-adhesive layer 11 side was in contact with each other and thermocompression bonded with a 120 ° C. heat roll to be integrated.

  A sanitary napkin was joined to this to produce an individual packaging structure.

  As shown in Table 2, in comparison with the sanitary napkin individual packaging structure using the paper release paper of Comparative Example 1 to be described later, a supple feel is obtained, the sound is less uncomfortable when opened, and it is easy to take out. Good evaluation was obtained.

(Example 2)
The thermal adhesive layer 11, the intermediate layer 12, and the protective layer 13 made of a synthetic resin were formed by a T-die coextrusion molding machine with the composition and layer ratio shown in Table 1 with the thermal adhesive layer 11 as the casting roll side. At that time, an extrusion speed of 60 kg / h, a film width of 400 mm, a layer thickness of the above-mentioned layer ratio, and a total thickness of 25 μm were prepared. Got the product. The corona treatment was performed under the condition that the wetting tension according to JIS K 6768 was 42 mN / m.

  By providing the intermediate layer 12, the T-die film formation was further stabilized as compared with Example 1. Due to the stability of the film forming property, a film could be obtained at a higher extrusion speed.

  Next, a silicone coat was applied to the surface of the protective layer 13 made of a synthetic resin of the obtained laminated film.

  Further, a non-woven fabric was prepared, and the above heat-adhesive film was superposed on the center of the non-woven fabric so that the heat-adhesive layer 11 side was in contact with each other and thermocompression bonded with a 120 ° C. heat roll to be integrated.

  A sanitary napkin was joined to this to produce an individual packaging structure.

  As shown in Table 2, in comparison with the sanitary napkin individual packaging structure using the paper release paper of Comparative Example 1 to be described later, a supple feel is obtained, the sound is less uncomfortable when opened, and it is easy to take out. Good evaluation was obtained.

(Example 3)
An individual packaging structure was manufactured in the same manner as in Example 2 except that the composition shown in Table 1 was used for the protective layer 13 made of a synthetic resin.

  Since the protective layer 13 made of a synthetic resin was blended with polypropylene and polyethylene and made incompatible, shallow irregularities were formed on the surface.

  Since unevenness was formed on the surface, blocking was almost eliminated when the silicone coating was applied after the T-die film was formed, and it was possible to process and manufacture suitably.

  As shown in Table 2, in the same way as in Example 2, it provides a supple feel and makes the sound uncomfortable when opened compared to a sanitary napkin individual packaging structure using a paper release paper of Comparative Example 1 described later. Therefore, it was possible to obtain a good evaluation that was easy to take out.

Example 4
An individual packaging structure was manufactured in the same manner as in Example 2 except that LV570, which is an ethylene vinyl acetate copolymer, was used for the thermal adhesive layer 11.

  As shown in Table 2, in the same way as in Example 2, it provides a supple feel and makes the sound uncomfortable when opened compared to a sanitary napkin individual packaging structure using a paper release paper of Comparative Example 1 described later. Therefore, it was possible to obtain a good evaluation that was easy to take out.

(Example 5)
An individual packaging structure was manufactured in the same manner as in Example 2 except that NUC-6225, which was an ethylene ethyl acrylate copolymer, was used for the heat bonding layer.

  As shown in Table 2, in the same way as in Example 2, it provides a supple feel and makes the sound uncomfortable when opened compared to a sanitary napkin individual packaging structure using a paper release paper of Comparative Example 1 described later. Therefore, it was possible to obtain a good evaluation that was easy to take out.

(Comparative Example 1)
Laminate a polyethylene film with a thickness of 12μ on 100% pulp paper with a basis weight of 22g / m ² , apply corona treatment on it, and then apply a silicone coat to form a release layer to obtain a paper release paper It was.

  A nonwoven fabric was prepared in the same manner as in Example 1, and was laminated so that the paper side of the paper release paper was in contact with the central portion of the nonwoven fabric and integrated with a hot-melt adhesive.

  When integrating with a hot melt type adhesive, the hot melt type adhesive was applied only to 20% of the area of the paper release paper.

  As shown in Table 2, compared to the sanitary napkin individual packaging structure using the heat-adhesive release film of Examples 1 to 5 described above, because paper is used, the feel is terrible and sounds when opened. For this reason, some monitors may feel uncomfortable, and since it is slightly deformed when taken out, it has been evaluated that it is difficult to remove.

(Comparative Example 2)
A film was obtained in the same manner as in Example 2 except that the thermal adhesive layer 11 was not constituted.

  Although it tried to heat-bond to a nonwoven fabric similarly to Example 2, it was not able to be integrated.

(Comparative Example 3)
A film was obtained in the same manner as in Example 2 except that the intermediate layer 12 and the protective layer 13 were not constituted.

  Although it tried to heat-bond to a nonwoven fabric similarly to Example 2, the film deform | transformed by the contact with a hot roll, and the favorable individual packaging structure was not able to be obtained.

1: Thermal adhesive release film 11: Thermal adhesive layer 12: Intermediate layer 13: Protective layer 14: Release layer 2: Base material 3: Absorbent article 4: Adhesive layer

Claims (5)

At least the heat-bonding layer, a protective layer made of synthetic resin, and sequentially have a release layer,
The thermal adhesive layer is formed by combining any one or two or more of the following (A) to (C):
A heat-adhesive release film , wherein the heat-adhesive layer is thermally bonded to an inner surface of a packaging material for individually packaging absorbent articles .
(A) Ethylene / α-olefin copolymer polymerized using a single site catalyst
(B) Ethylene / vinyl acetate copolymer
(C) Ethylene / (meth) acrylic acid ester copolymer Thermoadhesive release film according to claim 1, wherein the synthetic resin for forming the protective layer made of the synthetic resin is polypropylene and / or propylene · alpha-olefin copolymer. Thermoadhesive release film according to claim 1 or 2, characterized in that an intermediate layer mainly composed of polyethylene between the protective layer comprising the synthetic resin and the heat-bonding layer. A packaging material for individually packaging an absorbent article, wherein the thermal adhesive release film according to any one of claims 1 to 3 is provided on the inner surface of the packaging material by thermally bonding the thermal adhesive layer. Packaging material. The packaging material according to claim 4 , wherein the material is a non-woven fabric.

Images