JP2019218093A - Packing member - Google Patents

Abstract

To provide a packing member which can hold an article by use of the tension between a base material and a stretchable film, and can prevent the held article from dropping.SOLUTION: A packing member 1 includes a sheet-like base material 10 and a stretchable film 30 provided on one side of the base material 10, and holds an article 100 between the base material 10 and the stretchable film 30. The base material 10 has a center part 13 in which the article 100 is placed, fold-back parts 11, 12 provided on one side or both sides in a first direction of the center part 13, and bent parts 14, 15 provided between the center part 13 and the fold-back parts 11, 12, wherein the stretchable film 30 is adhered on the fold-back parts 11, 12. The packing member comprises fold-back state maintaining means (engaging pieces 16 to 19 and engaging holes 25 to 28) for maintaining the fold-back state of the fold-back parts 11, 12 obtained by folding back the base material 10 at positions of the bent parts 14, 15 so that the side on which the stretchable film 30 is provided is located on the outside.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a packing member for packing articles.

Conventionally, when packing and transporting goods in a packing container such as a cardboard box, in order to prevent the goods from being shaken inside the packing container and colliding with the packing container during transportation, cushioning such as styrofoam or an air cap is used. The material may be packed in the gap between the packing container and the article.
However, since the cushioning material is bulky in nature, there is a problem that the volume as waste is large.
Therefore, a method has been proposed in which articles are packed in a packing container without using the cushioning material. Patent Document 1 discloses an article transporter including an inner body including a baseboard having a rising portion on both ends and a falling portion on both sides, a holding sheet having both ends fixed to both ends of the baseboard, and an outer box. Packaging has been proposed. In the interior body, by folding the falling part downward in a state where the article is inserted between the baseboard and the holding sheet, the holding sheet is tensioned and the article is pressed against the baseboard. I have. Thereafter, the rising portion is turned upward, and the interior body is housed in the outer box in that state.

Japanese Patent No. 4395675

  However, in the interior body described in Patent Literature 1, since the strong restoring force due to the tension of the holding sheet is used, the folded rising before the interior body is stored in the outer box or after the inner body is removed from the outer box. The part and the falling part may unintentionally open, and the article may fall off from between the baseboard and the holding sheet.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a packing member that can clamp an article by using tension between a base material and an elastic film, and that can prevent falling of the clamped article. And

The present invention has the following aspects.
<1> A packing member that includes a sheet-shaped base material and an elastic film provided on one surface of the base material, and that sandwiches an article between the base material and the elastic film,
The base material includes a central portion where the article is arranged, a folded portion provided on one or both sides in the first direction of the central portion, and a fold provided between the central portion and the folded portion. Having a bent portion, the stretchable film is attached to the folded portion,
When the base material is bent at the position of the bent portion so that the side on which the elastic film is provided is on the outside and the folded portion is folded, the folded state is maintained. A packing member comprising a maintenance means.
<2> The packing member according to <1>, wherein the folded portion is provided on both sides of the central portion in the first direction.
<3> The folded state maintaining means includes a first engagement portion, and a second engagement portion engageable with the first engagement portion. 2 to maintain the folded state of the folded part by engaging with the engaging part of (2),
The packing member according to <1>, wherein the first engagement portion is provided in the folded portion, and the second engagement portion is provided in the central portion.
<4> The folded state maintaining means includes a first engagement portion, and a second engagement portion engageable with the first engagement portion. 2 to maintain the folded state of the folded part by engaging with the engaging part of (2),
The first engaging portion is provided on each of the folded portions on both sides in the first direction of the central portion, and the second engaging portion is provided on the central portion, or the first direction of the central portion is provided. The packing member according to <2>, wherein the first engagement portion is provided on one of the folded portions on both sides of the package, and the second engagement portion is provided on the other.
<5> The above <3> or <3>, wherein one of the first engagement portion and the second engagement portion is an engagement piece, and the other is an engagement hole into which the engagement piece can be inserted. <4> A packing member.

  The packing member of the present invention can clamp an article by utilizing tension between a base material and an elastic film. Further, the sandwiched article can be prevented from falling off.

It is a top view showing the member for packing concerning one embodiment. It is a top view which shows the state which inserted the article between the base material of the member for packing shown in FIG. 1, and an elastic film. FIG. 3 is a perspective view showing a state in which the base material of the packing member in the state shown in FIG. 2 is being bent. FIG. 2 is a perspective view showing a state in which the base material of the packing member in the state shown in FIG. 2 is bent and the folded portion is folded, and then the engaging pieces of the folded portion are engaged with the engaging holes in the central portion. It is. After the base material of the packing member in the state shown in FIG. 2 is bent and the folded portion is folded, the engaging piece of the folded portion is engaged with the engaging hole in the center portion (the article is FIG. After the base material of the packing member in the state shown in FIG. 2 is bent and the folded portion is folded, the engaging piece of the folded portion is engaged with the engaging hole in the center portion (the article is FIG.

Hereinafter, a packing member of the present invention will be described with reference to the accompanying drawings and embodiments.
FIG. 1 is a top view showing a packing member 1 according to one embodiment of the present invention. FIG. 2 is a top view showing a state in which an article is inserted between the base material of the packaging member 1 and the elastic film. FIG. 3 is a perspective view showing a state in which the base material of the packaging member 1 is being bent with the article inserted as shown in FIG. FIG. 4 shows a state where the folded portion of the packing member 1 is folded in a state where the article is inserted as shown in FIG. 2 and then the engaging piece of the folded portion is engaged with the engaging hole in the central portion. It is a perspective view which shows the state of. FIGS. 5 and 6 show a state in which the folded part of the packing member 1 is folded in a state where the article is inserted as shown in FIG. 2, and the engaging piece of the folded part is engaged with the engaging hole in the central part. It is the top view and the bottom view which show the state (state where the article was packed with the packing member).

The packing member 1 includes a sheet-shaped base material 10 and a transparent stretchable film 30. The elastic film 30 is provided on one surface of the base material 10, and sandwiches the article 100 between the base material 10 and the elastic film 30.
The base material 10 and the stretch film 30 are each formed in a substantially rectangular shape. Therefore, the packing member 1 is also substantially rectangular.
In the following, one surface of the substrate 10 (the surface on which the stretchable film 30 is provided) is referred to as “upper surface”, the other surface of the substrate 10 is referred to as “lower surface”, and the longitudinal direction of the packaging member 1 is referred to as “first direction”. , And a direction orthogonal to the first direction is referred to as a “second direction”.

The base material 10 is provided with a central portion 13 on which the article 100 is arranged, folded portions 11 and 12 provided on both sides of the central portion 13 in the first direction, and provided between the central portion 13 and the folded portions 11 and 12. And bent portions 14 and 15.
The folded portion 11 extends from one edge of the base material 10 in the first direction. The folded portion 12 extends from the other edge of the substrate 10 in the first direction.

  The bent portions 14 and 15 allow the base material 10 to be bent at the positions of the bent portions 14 and 15 such that the side on which the stretchable film 30 is provided (upper surface side) is located outside. It is. In the present embodiment, the bent portion 14 is composed of a fold line 14a formed linearly in the second direction and a pair of cutouts 14b and 14c extending inward from both edges of the base material 10 in the second direction. I do. The bent portion 15 is composed of a fold line 15 a formed linearly along the second direction and a pair of cutouts 15 b and 15 c extending inward from both edges of the base material 10 in the second direction.

An elastic film 30 is adhered to the folded portions 11 and 12. Therefore, both edges in the first direction of the stretchable film 30 are the attachment parts 31 and 32 attached to the base material 10.
The stretch film 30 is not welded to the base material 10 in portions other than the sticking portions 31 and 32. Therefore, the article 100 can be inserted between the central portion 13 of the base material 10 and the elastic film 30. When the base material 10 is bent as described above, the stretch film 30 is stretched.

The folded portion 11 is formed with two engaging pieces 16 and 17 (first engaging portions). The engaging pieces 16 and 17 are respectively defined by a pair of cuts 21 and 22 formed at positions separated from both edges in the second direction of the folded portion 11. The pair of cuts 21 and 22 extend inward from the edge of the base 10 on the side of the folded portion 11 in the first direction, and penetrate the base 10 and the stretchable film 30 thereon in the thickness direction.
The folded portion 12 is formed with two engaging pieces 18 and 19 (first engaging portions). The engagement pieces 18 and 19 are respectively defined by a pair of cuts 23 and 24 formed at positions separated from both edges of the folded portion 12 in the second direction. The pair of cuts 23 and 24 extend inward from the edge of the base material 10 on the side of the folded portion 12 in the first direction, and penetrate the base material 10 and the elastic film 30 thereon in the thickness direction.

Four engagement holes 25, 26, 27, 28 (second engagement portions) are formed in the central portion 13. The engagement holes 25, 26, 27, 28 are formed in a straight line extending in the second direction, and penetrate the base material 10.
The engagement holes 25 and 26 are formed so that the engagement pieces 16 and 17 of the folded portion 11 can be engaged when the folded portion 11 is folded. That is, in the second direction, the positions of both ends of the engagement holes 25 and 26 substantially coincide with both ends of the engagement pieces 16 and 17, that is, the positions of the pair of cuts 21 and 22. In the first direction, the distance from the fold line 14a to the engagement holes 25 and 26 is equal to the distance from the fold line 14a to the base of the engagement pieces 16 and 17, that is, the end of the pair of cuts 21 and 22 on the fold line 14a side. They almost match.
Similarly, the engagement holes 27 and 28 are formed so that the engagement pieces 18 and 19 of the folded portion 12 can be engaged when the folded portion 12 is folded.

  The engagement pieces 16, 17, 18, 19 and the engagement holes 25, 26, 27, 28 constitute a folded state maintaining means for maintaining the state when the pair of folded parts 11, 12 are folded. I do.

  Examples of the substrate 10 include a paper substrate, a resin sheet, and a nonwoven fabric. Among these substrates, a paper substrate is preferable, and in terms of strength, a corrugated cardboard or cardboard is more preferable, and a corrugated cardboard is more preferable.

Examples of the stretchable film 30 include the following stretchable films (1) and (2).
Stretchable film (1), comprising: a thermoplastic elastomer-containing layer; and a first polyolefin-based resin-containing layer provided on one surface side of the thermoplastic elastomer-containing layer, wherein the first polyolefin-based resin-containing layer is provided. But a stretchable film containing a polarizer.
Stretchable film (2): a thermoplastic elastomer-containing layer, a second outer layer provided on one side of the thermoplastic elastomer-containing layer, and a first outer layer provided on the other side of the thermoplastic elastomer-containing layer An outer layer, wherein the second outer layer contains a polymer having a density of 0.87 g / cm ³ or more, and the first outer layer has a temperature of 20 ° C. with respect to a melting point T _{m2 of the} polymer contained in the second outer layer. An elastic film containing a polymer having a high melting point _Tm1 .
In this specification, the melting point is a value determined by differential scanning calorimetry.
When the stretchable film (1) is used as the stretchable film 30, the first polyolefin-based resin-containing layer of the stretchable film (1) is thermally welded to the substrate 10. When the stretchable film (2) is used as the stretchable film 30, the second outer layer of the stretchable film (2) is thermally welded to the base material 10.
Among these stretchable films, the stretchable film (1) is preferable from the viewpoints of adhesive strength and low-temperature heat sealability. The stretch films (1) and (2) will be described later in detail.

As a method of manufacturing the packing member 1, for example, the following method is exemplified.
First, the base material is subjected to processing such as punching, bending, and pressing to obtain a base having a predetermined outer shape and having the bent portions 14, 15 and the engagement holes 25, 26, 27, 28 formed therein. The material 10 is manufactured. Next, the stretchable film 30 is overlaid on the base material 10, and both edges of the stretchable film 30 in the first direction are attached to the folded portions 11 and 12 of the base material 10, respectively. Thereafter, the notches 21, 22, 23, and 24 are formed in the pair of folded portions 11, 12, respectively, to form the engagement pieces 16, 17, 18, 19. Thereby, the packing member 1 is obtained.
The method of attaching the stretch film 30 is not particularly limited, and examples thereof include a method of heat welding, a method of attaching with an adhesive, and a method of attaching with a tape or the like. In terms of cost, the method of heat welding is preferable. Examples of the method of thermally welding the stretchable film 30 include a method of pressing a heated heat seal bar against the stretchable film 30 and a method of instantaneously melting the film with ultrasonic waves.

Next, a method of using the packing member 1 of the present embodiment will be described.
First, as shown in FIG. 2, the article 100 is inserted between the base material 10 of the packaging member 1 and the stretchable film 30 and arranged on the upper surface of the central portion 13.
Next, as shown in FIG. 3, the base material 10 is placed so that the side on which the stretchable film 30 is provided is located outside at the position of the bent portion 14, that is, the lower surface of the folded portion 11 and the lower surface of the central portion 13 are The folded portion 11 is folded so as to be in contact with the folded portion 11 so that the folded portion 11 is folded. Further, the base material 10 is bent at the position of the bent portion 15 so that the side on which the stretchable film 30 is provided is on the outside, so that the folded portion 12 is in a folded state. As a result, the stretchable film 30 is stretched, and the article 100 between the base material 10 and the stretchable film 30 is pressed against the base material 10 with a stronger force than before the folded portions 11 and 12 are folded.
Next, as shown in FIG. 4, the engaging pieces 16, 17, 18, 19 of the folded portions 11, 12 are folded back toward the central portion 13 and inserted into the engaging holes 25, 26, 27, 28. Thereby, as shown in FIGS. 5 and 6, the engagement pieces 16, 17, 18, and 19 are in a state of being locked in the engagement holes 25, 26, 27, and 28. If necessary, bend the engaging pieces 16, 17, 18, and 19 inserted into the engaging holes 25, 26, 27, and 28 so that the engaging pieces 16, 17, 18, and 19 do not easily fall out of the engaging holes 25, 26, 27, and 28. You may.

The packing member 1 in which the article 100 is packed as described above is housed in a packing container, for example, and is used for transporting the article 100.
Examples of the packing container include a box and a bag, and a box is usually used. As a box, in order to prevent the packing member 1 packed with the article 100 from moving in the box during transportation, the outer shape of the bottom surface is usually the outer shape of the packing member 1 packed with the article 100, That is, a material that substantially matches the outer shape of the central portion 13 is used.
Examples of the material of the packing container include paper, resin, and the like. Among them, paper is preferable, and cardboard is more preferable. As a packing container, a cardboard box is particularly preferred.

  In the packing member 1 of the present embodiment described above, the folded portions 11 and 12 are folded so that the tension between the stretchable film 30 and the base material 10 and the stretchable film 30 can be used. The article 100 can be pinched. In addition, since the folded portions 11 and 12 are provided with folded state maintaining means (engaging pieces 16, 17, 18, 19 and engaging holes 25, 26, 27, 28) for maintaining the folded state, the base material 10 It is possible to prevent the article 100 held between the elastic film 30 and the elastic film 30 from falling off. In other words, when the folded portions 11 and 12 are folded, a restoring force is exerted on the stretched stretch film 30 to return to the original position, but the engaging pieces 16, 17, 18 and 19 are engaged with the engaging holes 25, 26 and 25. By locking to the portions 27 and 28, the folded portions 11 and 12 can be prevented from unfolding by the action of the restoring force, thereby preventing the tension of the elastic film 30 from weakening and the article 100 falling out.

<Stretchable film (1)>
The stretch film (1) includes a thermoplastic elastomer-containing layer and a first polyolefin-based resin-containing layer. The stretchable film (1) may include a second polyolefin-based resin-containing layer on the other surface side of the thermoplastic elastomer-containing layer.

The thermoplastic elastomer-containing layer is a layer containing a thermoplastic elastomer. By having the thermoplastic elastomer-containing layer, the stretchable film (1) has stretchability.
The thermoplastic elastomer is a thermoplastic resin having rubber elasticity at normal temperature.
Examples of the thermoplastic elastomer include an olefin-based thermoplastic elastomer, a styrene-based thermoplastic elastomer, and a polyester-based thermoplastic elastomer. Among these elastomers, olefin-based thermoplastic elastomers are preferred because of their good adhesion to the first polyolefin-based resin-containing layer and good adhesion to the second polyolefin-based resin-containing layer.
Examples of the olefin-based thermoplastic elastomer include an ethylene-α-olefin copolymer. As the α-olefin constituting the ethylene-α-olefin copolymer, for example, propylene, 1-butene, 1-hexene, 1-octene and the like can be mentioned. The ethylene-α olefin copolymer may be a random copolymer or a block copolymer, but a block copolymer is preferred.

The thermoplastic elastomer may have a melting point or may not have a melting point.
The melting point of the thermoplastic elastomer having a melting point is preferably lower than the melting point of the polyolefin-based resin contained in the second polyolefin-based resin-containing layer from the viewpoint of heat-sealing processability. It is more preferable that the temperature is lower by 20 ° C. or more than the melting point of the polyolefin resin contained. As a result, the heat sealability is excellent, and the shape of the film is changed at the time of heat welding to the base material, and in some cases, it is possible to prevent the end of the welded portion from being broken (cut edge).
The melting point of the thermoplastic elastomer having a melting point is preferably 130 ° C. or less for practical use. The melting point of the thermoplastic elastomer having a melting point is preferably 80 ° C. or higher for practical use.
As the thermoplastic elastomer, a commercially available thermoplastic elastomer may be used, or a thermoplastic elastomer manufactured by a known manufacturing method may be used. Commercially available thermoplastic elastomers include ExxonMobil's Vistamax 6102FL (no melting point), Vistamax 8880 (no melting point), Dow Chemical's Infuse9007 (melting point 119 ° C), and the like.

The thermoplastic elastomer contained in the thermoplastic elastomer-containing layer may be one type or two or more types.
The content of the thermoplastic elastomer is preferably from 70 to 100% by mass, more preferably from 90 to 100% by mass, and preferably from 95 to 100% by mass, based on the total mass of the thermoplastic elastomer-containing layer. Is more preferred. When the content of the thermoplastic elastomer is equal to or more than the lower limit, the stretchability of the stretchable film (1) becomes sufficiently high, and the holding property of the article can be further improved.

If necessary, the thermoplastic elastomer-containing layer may contain a polymer other than the thermoplastic elastomer as long as the physical properties of the stretchable film (1), in particular, the stretchability are not impaired.
As other polymers, polyolefins such as polyethylene and polypropylene are preferable in that the desired performance can be easily obtained.

  The thermoplastic elastomer-containing layer may contain, as necessary, components other than the thermoplastic elastomer and other polymers, such as an antioxidant, a weather stabilizer, an antistatic agent, an antifogging agent, a metal soap, a wax, a fungicide, and an antibacterial agent. Various additives such as an agent, a nucleating agent, a flame retardant, and a slip agent may be contained.

The thickness of the thermoplastic elastomer-containing layer is preferably from 20 to 50 μm, more preferably from 25 to 40 μm. When the thickness of the thermoplastic elastomer-containing layer is equal to or more than the lower limit, the stretchability of the stretchable film (1) can be sufficiently secured, and the holding property of the article can be further improved. When the thickness of the thermoplastic elastomer-containing layer is equal to or less than the upper limit, the article can be held with an appropriate holding force that is not too strong.
In the present specification, the thickness of the layer is a value obtained by observing the cross section of the packaging film using an optical microscope or an electron microscope, measuring the thickness at five or more locations, and averaging the measured thickness.

The first polyolefin-based resin-containing layer contains a polyolefin-based resin.
The polyolefin resin is a resin having an olefin unit (ethylene unit, propylene unit, etc.). The content of the olefin unit is, for example, 60 to 100% by mass based on the total mass of the polyolefin-based resin.
Hereinafter, the polyolefin-based resin contained in the first polyolefin-based resin-containing layer is also referred to as “first polyolefin-based resin”.

Examples of the first polyolefin resin include block polypropylene, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), and ethylene. -Ethyl acrylate copolymer (EEA) and the like. Among these polymers, block polypropylene is preferred because of its excellent elasticity and flexibility.
The block polypropylene is a resin in which a rubber component is contained in a homopolypropylene matrix or a random polypropylene matrix containing ethylene units at a ratio of 5% by mass or less. As the rubber component, for example, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, propylene-butene copolymer, propylene-hexene copolymer, propylene -Octene copolymer and the like.
Usually, the block polypropylene forms a homopolypropylene or a random polypropylene serving as a matrix in the first-stage polymerization, and forms a rubber component in the second-stage polymerization in the presence of the homopropylene or the random polypropylene. By forming the rubber component in the matrix by polymerization as described above, the dispersibility of the rubber component can be improved.

The density of the first polyolefin resin is preferably 0.87 g / cm ³ or more, more preferably 0.88 g / cm ³ or more. When the density is equal to or more than the lower limit, stickiness of the surface of the first polyolefin-based resin-containing layer can be suppressed, and blocking when the stretchable film (1) is formed into a roll can be prevented.
The density of the first polyolefin-based resin is preferably 0.91 g / cm ³ or less for practical use of the stretchable film (1).

The first polyolefin-based resin typically has a melting point.
The melting point of the first polyolefin-based resin is preferably 130 ° C. or lower. When the melting point is 130 ° C. or less, the low-temperature adhesiveness of the stretchable film (1) is excellent, and sufficient adhesive strength can be obtained even when heat-sealing to a substrate at a lower temperature (eg, 120 to 145 ° C.) than in the past. .
The practical melting point of the first polyolefin-based resin is preferably 80 ° C. or higher.
In the case of block polypropylene, the melting point and crystallinity (heat of fusion) can be adjusted by the ratio and structure of the rubber component contained in the resin.

The first polyolefin-based resin contained in the first polyolefin-based resin-containing layer may be one type or two or more types.
The content of the first polyolefin-based resin is preferably from 80 to 99% by mass, more preferably from 83 to 96% by mass, and more preferably from 85 to 99% by mass, based on the total mass of the first polyolefin-based resin-containing layer. More preferably, it is 95% by mass. When the content of the first polyolefin-based resin is equal to or more than the lower limit, the stretchability of the stretchable film (1) becomes sufficiently high. When the content of the first polyolefin resin is equal to or less than the upper limit, the low-temperature adhesion of the stretchable film (1) is more excellent.

The first polyolefin-based resin-containing layer contains a polarity-imparting agent.
The polarity-imparting agent has an action of imparting polarity to the first polyolefin-based resin. By imparting polarity to the first polyolefin-based resin, the adhesion between the first polyolefin-based resin-containing layer and a substrate such as a paper substrate is enhanced, and heat welding to the substrate is performed at a lower temperature than before. However, sufficient adhesive strength can be obtained.

Examples of the polarizer include a polyolefin resin having a carboxylic anhydride structure in the molecule, a polyolefin resin having an acrylic acid structure in the molecule, and a polyolefin resin having an epoxy structure in the molecule. Of these, polyolefin resins having a carboxylic anhydride structure in the molecule are preferred in view of compatibility with the first polyolefin resin and industrial availability.
Examples of the carboxylic anhydride include acetic anhydride, propionic anhydride, oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, and benzoic anhydride.
Examples of the polyolefin resin having a carboxylic anhydride structure in the molecule include polypropylene having a carboxylic anhydride structure in the molecule, polyethylene having a carboxylic anhydride structure, and the like.
Note that the polyolefin-based resin functioning as a polarity-imparting agent is not treated as the first polyolefin-based resin, but is treated as a polarity-imparting agent.

Polarizing agents typically have a melting point.
The melting point of the polarity-imparting agent is preferably 140 ° C. or lower, more preferably 137 ° C. or lower. When the melting point of the polarity-imparting agent is equal to or less than the above upper limit, the adhesive strength when performing heat welding to the substrate at a low temperature is more excellent.
As the melting point of the polarizer is lower, the time required for heat welding the stretchable film (1) can be reduced, and the lower limit of the melting point of the polarizer is not particularly limited. It is preferable that

The acid value of the polarizer is preferably from 0.5 to 200, more preferably from 1.0 to 150. When the acid value is equal to or more than the lower limit, the effect of imparting polarity is more excellent. When the acid value is equal to or less than the upper limit, compatibility with the first polyolefin-based resin is ensured, and the moldability is good.
In the present specification, the acid value is a value determined according to JIS K0070.

The polarity-imparting agent contained in the first polyolefin-based resin-containing layer may be one type or two or more types.
The content of the polarizer is preferably 1 to 15% by mass, more preferably 2 to 10% by mass, and more preferably 3 to 8% by mass, based on the total mass of the first polyolefin-based resin-containing layer. Is more preferable. When the content of the polarity-imparting agent is at least the lower limit, the low-temperature adhesiveness of the stretchable film (1) is more excellent. When the content of the polarizer is equal to or less than the upper limit, the stretchability of the stretchable film (1) is sufficiently high.

If necessary, the first polyolefin-based resin-containing layer may contain, as components other than the first polyolefin-based resin and the polarity-imparting agent, an antioxidant, a weather stabilizer, an antistatic agent, an anti-fogging agent, a metal soap, and a wax. And various additives such as fungicides, antibacterial agents, nucleating agents, flame retardants, slip agents and the like.
In particular, the first polyolefin-based resin-containing layer preferably contains a slip agent in order to further prevent blocking. Among slip agents, an organic slip agent is preferable, and an amide-based slip agent is more preferable, since the anti-blocking property is particularly excellent. Examples of the amide slip agent include erucic acid amide and stearic acid amide, and erucic acid amide is preferable.

  The thickness of the first polyolefin-based resin-containing layer is preferably from 1 to 10 μm, more preferably from 2 to 6 μm. When the thickness of the first polyolefin-based resin-containing layer is at least the lower limit, blocking when the stretchable film (1) is formed into a roll can be further prevented. When the thickness of the first polyolefin-based resin-containing layer is equal to or less than the upper limit, the stretchability of the stretchable film (1) can be sufficiently ensured, and the holding property of the article can be further improved.

The second polyolefin-based resin-containing layer contains a polyolefin-based resin.
Hereinafter, the polyolefin-based resin contained in the second polyolefin-based resin-containing layer is also referred to as “second polyolefin-based resin”.
Examples of the second polyolefin-based resin include homopolypropylene, random polypropylene, block polypropylene and the like. Among them, random polypropylene is preferred because of its excellent flexibility and high melting point.

The second polyolefin-based resin typically has a melting point.
The melting point of the second polyolefin-based resin is preferably higher than the melting point of the first polyolefin-based resin, more preferably (the melting point of the first polyolefin-based resin + 20 ° C.) or more. (The melting point of the base resin + 30 ° C.) or more. If the melting point of the second polyolefin-based resin is higher than the melting point of the first polyolefin-based resin, it is possible to further prevent the stretchable film (1) from being blown during thermal welding to the base material.
In terms of facilitating the production of the stretch film (1), the melting point of the second polyolefin-based resin is preferably equal to or lower than (the melting point of the first polyolefin-based resin-70 ° C).
The melting point of the second polyolefin-based resin is preferably 140 ° C. or higher.
The melting point of the second polyolefin-based resin is practically preferably 180 ° C. or less.
In the case of random polypropylene, the melting point can be adjusted by the content ratio of the ethylene unit. The melting point tends to decrease as the content ratio of the ethylene unit in the random polypropylene increases.

The second polyolefin-based resin contained in the second polyolefin-based resin-containing layer may be one type or two or more types.
The content of the second polyolefin-based resin is preferably from 70 to 100% by mass, more preferably from 90 to 100% by mass, and preferably from 95 to 100% by mass, based on the total mass of the second polyolefin-based resin-containing layer. More preferably, it is 100% by mass. When the content of the second polyolefin-based resin is equal to or more than the lower limit, the heat resistance of the stretchable film (1) is more excellent.

  The second polyolefin-based resin-containing layer may contain, as necessary, components other than the second polyolefin-based resin, such as an antioxidant, a weather stabilizer, an antistatic agent, an antifogging agent, a metal soap, a wax, and a fungicide. And various additives such as antibacterial agents, nucleating agents, flame retardants, slip agents and the like.

  The thickness of the second polyolefin-based resin-containing layer is preferably from 3 to 10 μm, more preferably from 3 to 6 μm. When the thickness of the second polyolefin-based resin-containing layer is equal to or more than the lower limit, the heat resistance of the stretchable film (1) is improved, and the stretchable film (1) is blown off during thermal welding to the substrate. More preventable. When the thickness of the second polyolefin-based resin-containing layer is equal to or less than the upper limit, the stretchability of the stretchable film (1) can be sufficiently secured, and the holding property of the article can be further improved.

The stretchable film (1) may be an unstretched film or a stretched film. When the stretchable film (1) is stretched, mechanical properties of the film, particularly shrinkage stress and permanent set, can be easily adjusted.
When the stretchable film (1) is a stretched film, it may be a uniaxially stretched film or a biaxially stretched film.

  Irregularities may be formed on the surface of the elastic film (1), that is, on one surface (the outer surface of the first polyolefin-based resin-containing layer) and the other surface of the elastic film (1). If irregularities are formed on the surface of the stretchable film (1), the slipperiness increases, and blocking of the stretchable film (1) can be further prevented. The unevenness may be formed on only one surface of the stretchable film (1), may be formed only on the other surface, or may be formed on both one surface and the other surface. The unevenness can be formed by a known method such as embossing.

The stretch film (1) is manufactured, for example, by the following method.
A thermoplastic elastomer and optional components (other polymers, additives, etc.) are mixed to prepare a thermoplastic elastomer layer-forming resin material. When no optional component is contained, the resin material for forming a thermoplastic elastomer layer comprises only a thermoplastic elastomer.
A first polyolefin-based resin-containing layer-forming resin material is prepared by mixing a first polyolefin-based resin, a polarity-imparting agent, and an optional component (eg, an additive). When no optional component is contained, the first polyolefin-based resin-containing layer-forming resin material comprises the first polyolefin-based resin and a polarity-imparting agent.
If necessary, a second polyolefin-based resin and an optional component (additive or the like) are mixed to prepare a second polyolefin-based resin-containing layer-forming resin material. When no optional component is contained, the resin material for forming the second polyolefin-based resin-containing layer comprises only the second polyolefin-based resin.

  When mixing additives when preparing each resin material, a masterbatch containing the additives and the diluting resin may be mixed with the thermoplastic elastomer, the first polyolefin-based resin, or the second polyolefin-based resin. . For example, when the first polyolefin-based resin-containing layer contains a slip agent, the first polyolefin-based resin-containing layer-forming resin material is obtained using the first polyolefin-based resin, the slip agent, and the diluent resin. And a masterbatch containing the same. When a mixing method using a master batch is applied, the dispersibility of the additive in the thermoplastic elastomer, the first polyolefin-based resin, or the second polyolefin-based resin can be easily improved.

Next, the resin material for forming a thermoplastic elastomer layer and the resin material for forming a first polyolefin-based resin-containing layer are supplied to an extruder capable of forming a multilayer, and each resin material is extruded, and one of the thermoplastic elastomer layers is extruded. Are laminated so that the first polyolefin-based resin-containing layer is arranged on the side of the surface of. Alternatively, a resin material for forming a thermoplastic elastomer layer, a resin material for forming a first polyolefin-based resin-containing layer, and a resin material for forming a second polyolefin-based resin-containing layer are supplied to an extruder capable of forming a multilayer. The resin material is extruded and laminated so that the first polyolefin-based resin-containing layer is arranged on one side of the thermoplastic elastomer layer and the second polyolefin-based resin-containing layer is arranged on the other side. Extruders that can be multilayered include, for example, those that include a multi-manifold die or feedblock system at the tip of the extruder.
The melted two-layer or three-layer laminate formed by the extruder is brought into close contact with the peripheral surface of the cast roll and cooled to obtain the stretchable film (1). When the casting method of forming a film using a cast roll is applied, the productivity of the stretchable film (1) can be easily improved.

  If necessary, the stretch film (1) may be stretched. Examples of the method of stretching the stretchable film (1) include a method of stretching the film using a roll, a method of stretching the film by gripping the film with a clip, and a method of stretching the film with a pair of gears. Can be Among the above-mentioned stretching methods, a method in which a film is sandwiched between a pair of gears and stretched is preferable in that productivity can be easily increased.

  When embossing is performed on the surface of the elastic film (1), the peripheral surface of the embossing roll having irregularities on the peripheral surface may be brought into close contact with the surface of the elastic film (1) before or after the cooling. . The embossing roll may be a cast roll or a heated pinch roll.

  In addition, the method of manufacturing the stretchable film (1) is not limited to the above-described manufacturing method. For example, in the above-mentioned production method, a stretched film (1) may be obtained by inflation molding a two-layer or three-layer laminate in a molten state formed by an extruder.

<Stretchable film (2)>
The stretchable film (2) includes a thermoplastic elastomer-containing layer, a second outer layer provided on one surface of the thermoplastic elastomer-containing layer, and a second outer layer provided on the other surface of the thermoplastic elastomer-containing layer. 1 outer layer.
The thermoplastic elastomer-containing layer is the same as the thermoplastic elastomer-containing layer of the stretch film (1).

The first outer layer is a layer containing a polymer as a main component.
Examples of the polymer contained in the first outer layer include polyolefin resins such as homopolypropylene, random polypropylene, and block polypropylene. Among these polymers, random polypropylene is preferred because of its excellent flexibility and high melting point.

The first outer layer contains a polymer having a melting point T _m1 higher than the melting point T _{m2 of the} polymer contained in the second outer layer by 20 ° C. or more. When the melting point T _{m1 of the} polymer contained in the first outer layer is higher than the melting point T _{m2 of the} polymer contained in the second outer layer by 20 ° C. or more, the stretchable film (2) is blown off during thermal welding to the base material. Can be prevented.
It is preferable that the melting point T _m1 is higher than the melting point T _m2 by 30 ° C. or more. From the viewpoint of facilitating the production of the stretch film (2), the difference between the melting points T _m1 and T _m2 is preferably 70 ° C. or less.
The melting point _Tm1 is preferably 140 ° C. or higher. It is preferable that the melting point _Tm1 is 180 ° C. or less for practical use.
The melting point _Tm2 is preferably 120 ° C. or lower. The melting point _Tm1 is preferably 80 ° C. or higher for practical use.

The polymer contained in the first outer layer may be one kind or two or more kinds. When the first outer layer contains two or more polymers, the first outer layer may contain another polymer other than the polymer having the melting point _Tm1 as long as the physical properties of the stretchable film (2), in particular, the stretchability are not impaired. However, in order to obtain the desired performance, the other polymer is preferably a polyolefin such as polyethylene or polypropylene.

The content of the polymer contained in the first outer layer is preferably from 70 to 100% by mass, more preferably from 90 to 100% by mass, even more preferably from 95 to 100% by mass. When the content of the polymer contained in the first outer layer is at least the lower limit, the heat resistance of the stretchable film (2) will be sufficiently high.
In particular, in the first outer layer, the content of polymer having a melting point _{T m1} is 70 to 100 wt%, more preferably from 90 to 100 wt%, it is 95 to 100 wt% More preferred.

  In the first outer layer, if necessary, as components other than the polymer, antioxidants, weather stabilizers, antistatic agents, antifogging agents, metal soaps, waxes, fungicides, antibacterial agents, nucleating agents, Various additives such as a flame retardant and a slip agent may be included.

  The preferred thickness of the first outer layer is the same as the preferred thickness of the second polyolefin-based resin-containing layer of the stretch film (1).

The second outer layer is a layer containing a polymer as a main component. The second outer layer contains a polymer having a density of 0.87 g / cm ³ or more, and preferably contains a polymer having a density of 0.88 g / cm ³ or more. When the density of the polymer contained in the second outer layer is equal to or more than the lower limit, stickiness of the surface of the second outer layer can be suppressed, and blocking when the stretchable film (2) is formed into a roll can be prevented. The density of the polymer contained in the second outer layer is preferably 0.91 g / cm ³ or less for practical use of the stretchable film (2).

Examples of the polymer contained in the second outer layer include block polypropylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), Ethylene-ethyl acrylate copolymer (EEA) and the like. Among these polymers, block polypropylene is preferred because of its excellent elasticity and flexibility.
Examples of the block polypropylene include those similar to those described in the description of the first polyolefin-based resin-containing layer of the stretchable film (1).

  The polymer contained in the second outer layer may be one kind or two or more kinds. When two or more polymers are contained in the second outer layer, a polymer other than the polymer having the above-mentioned density may be contained as long as the physical properties of the stretchable film (2), in particular, the stretchability are not impaired. However, in order to obtain the desired performance, the other polymer is preferably a polyolefin such as polyethylene or polypropylene.

The content of the polymer contained in the second outer layer is preferably from 70 to 100% by mass, more preferably from 90 to 100% by mass, even more preferably from 95 to 100% by mass. When the content of the polymer contained in the second outer layer is at least the lower limit, the stretchability of the stretchable film will be sufficiently high.
In particular, in the second outer layer, the content of the polymer having a density of 0.87 g / cm ³ or more is preferably 70 to 100% by mass, more preferably 90 to 100% by mass, and 95 to 100% by mass. Is more preferable.

The second outer layer may contain various additives as components other than the polymer, if necessary. As the additives, the same additives as those that may be contained in the first outer layer can be used.
In particular, the second outer layer preferably contains a slip agent in order to further prevent blocking. Examples of the slip agent include the same ones as those described in the description of the first polyolefin-based resin-containing layer of the stretchable film (1).

  The preferred thickness of the second outer layer is the same as the preferred thickness of the first polyolefin-based resin-containing layer of the stretch film (1).

The stretchable film (2) may be an unstretched film or a stretched film. When the stretchable film (2) is stretched, mechanical properties of the film, particularly shrinkage stress and permanent set, can be easily adjusted.
When the stretchable film (2) is a stretched film, it may be a uniaxially stretched film or a biaxially stretched film.

The surface of the stretchable film (2), that is, the outer surface of the first outer layer and the outer surface of the second outer layer may be embossed to form irregularities. When the surface of the stretchable film (2) is embossed, the slipperiness is enhanced, and blocking of the stretchable film (2) can be further prevented.
The embossing may be formed only on the outer surface of the first outer layer, may be formed on the outer surface of the second outer layer, or may be formed on both the outer surface of the first outer layer and the outer surface of the second outer layer. .

  The stretch film (2) can be manufactured in the same manner as the stretch film (1).

  As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments. Each configuration and the combination thereof in the above-described embodiment are examples, and addition, omission, replacement, and other changes of the configuration are possible without departing from the spirit of the present invention.

For example, as the folded state maintaining means, the engaging pieces 16, 17, 18, 19 (first engaging portions) provided in the pair of folded portions 11, 12 and the engaging holes provided in the central portion 13 respectively. Although the example provided with 25, 26, 27, and 28 (the second engagement portion) has been described, the folded state maintaining means is not limited to this.
The first engagement portion may be an engagement hole, and the second engagement portion may be an engagement piece.
A first engaging portion may be provided on one of the pair of folded portions 11 and 12, and a second engaging portion may be provided on the other.
A hook or the like may be employed instead of the engagement piece.
Eyelets or the like may be employed instead of the engagement holes.
A folded state maintaining means other than the first engagement portion and the second engagement portion may be employed. As the folded state maintaining means other than the first engagement portion and the second engagement portion, an adhesive, an adhesive tape, a string, a hook-and-loop fastener, a spelling needle (staple), and the like can be given.

Although the example in which the folded portions 11 and 12 are provided on both sides of the central portion 13 in the first direction has been described, the folded portions may be provided only on one side of the central portion 13 in the first direction. In order to obtain a stronger tension, it is preferable that the folded portions 11 and 12 are provided on both sides of the central portion 13 in the first direction.
The example in which the fold lines 14a, 15a and the notches 14b, 14c, 15b, 15c constitute the bent portions 14, 15 has been described, but one of the fold lines 14a, 15a and the notches 14b, 14c, 15b, 15c is omitted. May be. Instead of the fold lines 14a and 15a, perforations, half cuts, printing, pressing, and the like may be employed.

The shapes of the base material and the stretch film are not limited to rectangular shapes, and may be appropriately selected according to the shape of the article to be packed and the shape of the packing container. Examples of the shape of the base material and the stretchable film include a rectangular shape, a square shape, a circular shape, an elliptical shape, and the like.
The stretch film may be opaque.

DESCRIPTION OF SYMBOLS 1 Packing member 10 Base material 11, 12 Folded part 13 Center part 14, 15 Folded part 14a, 15a Folded line 14b, 14c, 15b, 15c Notch 16, 17, 18, 19 Engagement piece (first engagement Part)
21, 22, 23, 24 Cuts 25, 26, 27, 28 Engagement holes (second engagement portions)
30 stretch films 31, 32 sticking part 100 article

Claims (5)

A sheet-like base material, comprising a stretch film disposed on one surface of the base material, a packing member for sandwiching an article between the base material and the stretch film,
The base material includes a central portion where the article is arranged, a folded portion provided on one or both sides in the first direction of the central portion, and a fold provided between the central portion and the folded portion. Having a bent portion, the stretchable film is attached to the folded portion,
When the base material is bent at the position of the bent portion so that the side on which the elastic film is provided is on the outside and the folded portion is folded, the folded state is maintained. A packing member comprising a maintenance means.   The packing member according to claim 1, wherein the folded portion is provided on both sides of the central portion in the first direction. The folded state maintaining means includes a first engagement portion and a second engagement portion engageable with the first engagement portion, wherein the first engagement portion and the second engagement portion are connected to each other. By maintaining the folded state of the folded part by engaging the mating part,
2. The packing member according to claim 1, wherein the first engagement portion is provided on the folded portion, and the second engagement portion is provided on the central portion. 3. The folded state maintaining means includes a first engagement portion and a second engagement portion engageable with the first engagement portion, wherein the first engagement portion and the second engagement portion are connected to each other. By maintaining the folded state of the folded part by engaging the mating part,
The first engaging portion is provided on each of the folded portions on both sides in the first direction of the central portion, and the second engaging portion is provided on the central portion, or the first direction of the central portion is provided. The packing member according to claim 2, wherein the first engagement portion is provided on one of the folded portions on both sides of the package, and the second engagement portion is provided on the other.   5. The device according to claim 3, wherein one of the first engagement portion and the second engagement portion is an engagement piece, and the other is an engagement hole into which the engagement piece can be inserted. 6. Packing materials.

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