JP3143726U - Packing material - Google Patents

Abstract

Provided is a packaging material that can prevent surface tearing and has antistatic performance while maintaining both rigidity and shock-absorbing performance, without impairing lightness.
A thickness 0.5 to 10 mm, on both surfaces of the polyolefin-based resin foam sheet A of apparent density 60~600kg / m ^3, thickness 0.3 to 3 mm, a polyolefin resin foam of apparent density 15~90kg / m ³ Sheet B [However, the apparent density of the foam sheet B is less than the apparent density of the foam sheet A. Is a polyolefin-based resin film having a thickness of 0.03 to 0.1 mm containing a polymer antistatic agent on the outer surface side of the foamed sheet B via a reinforcing material D. A packaging material in which C is laminated and bonded is used.
[Selection] Figure 3

Description

  The present invention relates to a packaging material, particularly a packaging material that can be suitably used for packaging precision electronic parts that dislike foreign matters such as static electricity and dust.

  Conventionally, corrugated cardboard is used as a returnable box or partition material. However, corrugated cardboard has a problem that paper dust comes out and contaminates the product, and a problem that it cannot withstand repeated use due to poor water resistance and oil resistance. Therefore, in applications where these are problems, a packaging material made of a synthetic resin such as a polypropylene foam board having light weight but rigidity is used as an alternative to corrugated cardboard.

  Here, in recent years, the number of precision devices that are vulnerable to impact has increased as packaging objects, and sufficient cushioning performance has been required for packing materials, particularly partitioning materials. A product obtained by laminating and bonding high foam sheets such as polyethylene and polypropylene for the purpose of application has been proposed (for example, Patent Documents 1 and 2) and used as a packaging material for precision equipment.

  In addition, if the packaged item is an electronic component that dislikes foreign matter such as static electricity or dust, the ability to prevent charging without contaminating the packaged item is required. For the purpose of antistatic performance, an antistatic agent is kneaded into the highly foamed sheet itself to be laminated and bonded for the purpose of providing buffering properties (for example, Patent Document 3). A highly foamed sheet in which an antistatic agent is kneaded is laminated and adhered to a foam board as a base material.

Japanese Patent Laid-Open No. 10-24540 JP-A-8-174737 JP 2005-194433 A

  However, since the laminate described in Patent Document 1 or 2 is a highly foamed sheet, the surface is easily torn when it comes into contact with an article to be packaged, and is difficult to repeatedly use depending on the application. .

  Further, in the case where the anti-foaming agent is kneaded into the high-foaming sheet itself described in Patent Document 3, since the strength itself is hardly improved, the same as the high-foaming sheet not containing the anti-static agent. It was easy to break and was difficult to use repeatedly.

  The present invention has been made in view of the actual situation of the background art described above, and its purpose is to achieve both the rigidity and the buffering performance of the conventional laminate, while not reducing the lightness. An object of the present invention is to provide a packaging material capable of preventing surface tearing and having antistatic performance.

In order to achieve the above-mentioned object, the present invention of claim 1 has a thickness of 0.3 to 10 mm on at least one side of a polyolefin resin foam sheet (A) having a thickness of 0.5 to 10 mm and an apparent density of 60 to 600 kg / m ^3. Polyolefin-based resin foamed sheet (B) of 3 mm and apparent density of 15 to 90 kg / m ³ [However, the apparent density of the foamed sheet (B) is less than the apparent density of the foamed sheet (A). ], Wherein the polyolefin resin film (C) containing a polymer type antistatic agent is laminated and adhered to the outer surface side of the foamed sheet (B). A material was used.

  According to a second aspect of the present invention, there is provided the packing material according to the first aspect, wherein a reinforcing material (D) is laminated and bonded between the foamed sheet (B) and the film (C). The thickness of (C) was 0.03-0.1 mm.

  Further, the present invention of claim 3 is the packing material of claim 2, wherein the reinforcing material (D) is a woven fabric, a nonwoven fabric, a stretched resin film or a fiber reinforced resin film having a thermoplastic resin as a base resin. It was a packing material characterized by being.

  According to a fourth aspect of the present invention, there is provided the packaging material according to the second aspect, wherein the reinforcing material (D) is a woven fabric or a non-woven fabric made of a stretched polyolefin resin.

The present invention of claim 5, packing material in any of the packaging material of the above claims 2 to 4, the basis weight of the reinforcing member (D), characterized in that a 10 to 50 g / m ² It was.

Further, the present invention of claim 6 is the packaging material according to any one of claims 1 to 5, wherein the base resin constituting the foamed sheet (A) is composed mainly of polyethylene having a density of 940 kg / m ³ or more. It was set as the packaging material characterized by doing.

Further, the present invention of claim 7 is the packaging material according to any one of claims 1 to 6, wherein the base resin constituting the foamed sheet (A) is polyethylene (X) having a density of 940 kg / m ³ or more. , A mixture of polyethylene (Y) having a density of less than 940 kg / m ³ , wherein the weight ratio of the polyethylene (X) to the polyethylene (Y) is 50:50 to 90:10 A material was used.

Moreover, the present invention of claim 8 is that, in the packaging material according to any of claims 1 to 7, the base resin constituting the foam sheet (B) is polyethylene having a density of less than 940 kg / m ^3. It was set as the characteristic packing material.

The present invention of claim 9 is a packaging material according to any one of claims 1 to 8, wherein the base resin constituting the film (C) has a density of 920 kg / m ³ or more and less than 940 kg / m ^3. A packing material characterized by being a chain low density polyethylene or a polyethylene having a density of 940 kg / m ³ or more.

  The invention of claim 10 is the packing material according to any one of claims 2 to 9, wherein the foam sheet (A), the foam sheet (B), the film (C) and the reinforcing material (D). The packaging material is characterized in that all of the base resin constituting the resin is a polyethylene resin.

  The invention of claim 11 is the packaging material according to any one of claims 2 to 5, wherein the foam sheet (A), the foam sheet (B), the film (C), and the reinforcing material (D). The packaging material is characterized in that all of the base material resins constituting polypropylene are polypropylene resins.

  Moreover, this invention of Claim 12 is a packing material in any one of the said Claims 2-11. On both surfaces of the said foam sheet (A), the said foam sheet (B) and the said reinforcing material (D) are provided. A packaging material characterized in that the films (C) are laminated and adhered to each other.

  The invention of claim 13 is the packaging material according to any one of claims 1 to 12, wherein a weight ratio of the foamed sheet (A) to the entire packaging material is 50% by weight or more. A packaging material characterized by

According to the packaging material according to the present invention of claim 1 described above, the polyolefin resin is highly foamed (at least on one surface of the foamed sheet (A) of low foaming of the polyolefin resin (apparent density 60 to 600 kg / m ³ ) ( Foam sheet (B) having an apparent density of 15 to 90 kg / m ³ ) [However, the apparent density of the foam sheet (B) is less than the apparent density of the foam sheet (A). In addition, a polyolefin resin film (C) having antistatic properties is laminated and adhered to the surface of the foamed sheet (B), so that it maintains semi-permanent while maintaining the conventional rigidity and buffering property. In addition, it is possible to provide a packaging material that has an antistatic performance that lasts for a long time and that is hard to tear.

  Moreover, according to the packaging material which concerns on this invention of above-mentioned Claim 2, since it decided to laminate-adhere the reinforcing material (D) further between the said foam sheet (B) and the said film (C), a film Even if the thickness of (C) is reduced, a sufficient tear prevention effect can be obtained, and a packaging material that is more lightweight can be provided.

  Moreover, according to the packaging material which concerns on this invention of said Claim 3, since the said reinforcing material (D) was made into the woven fabric, nonwoven fabric, stretched resin film, or fiber reinforced resin film which uses thermoplastic resin as a base resin, The entire packaging material is composed of a thermoplastic resin, and a packaging material that is more excellent in recyclability can be provided.

  Moreover, according to the packaging material which concerns on this invention of said Claim 4, since the said reinforcing material (D) was made into the woven fabric or nonwoven fabric which consists of an extending | stretching polyolefin resin, the whole packaging material is comprised from a polyolefin resin. Thus, it is possible to provide a packaging material that is more excellent in recyclability, is more resistant to tearing, and is resistant to tear strength and surface impact.

Moreover, according to the packing material which concerns on this invention of Claim 5 mentioned above, since the basic weight of the said reinforcing material (D) was 10-50 g / m < ² >, the balance between the effect of preventing surface tearing and lightness can be achieved. Packaging material can be provided.

Moreover, according to the packaging material which concerns on this invention of above-mentioned Claim 6, since the base resin of the said foam sheet (A) was based on polyethylene with a density of 940 kg / m < ³ > or more, it was more rigid and impact-resistant. It is possible to form a foam sheet (A) that is excellent in balance.

Moreover, according to the packaging material which concerns on this invention of above-mentioned Claim 7, the base resin of the said foam sheet (A) is polyethylene (X) with a density of 940 kg / m < ³ > or more and polyethylene with a density of less than 940 kg / m < ³ >. Since the weight ratio of the polyethylene (X) and the polyethylene (Y) is 50:50 to 90:10, the foamed sheet (A) is further excellent in balance between rigidity and impact resistance. ) Can be easily formed.

Moreover, according to the packing material which concerns on this invention of said Claim 8, since the base resin of the said foam sheet (B) was made into the low density polyethylene of density less than 940 kg / m < ³ >, the packing material which was more excellent in buffering performance Can be provided.

Further, according to the packaging material according to the present invention of claim 9, the base resin of the film (C) is a linear low density polyethylene having a density of 920 kg / m ³ or more and less than 940 kg / m ³ , or a density of 940 kg. Since it is made of high density polyethylene of / m ³ or more, it is possible to provide a packaging material that is more effective in preventing tearing.

  Moreover, according to the packaging material which concerns on this invention of above-mentioned Claim 10, since all the base resin which comprises each layer of a packaging material was used as the polyethylene-type resin, while becoming what was further excellent in recyclability, an adhesive agent was used. Even if it is not used, it is possible to provide a packaging material that can adhere each layer by heat fusion and has excellent cold shock resistance.

  In addition, according to the packaging material according to the present invention of claim 11 described above, since the base resin constituting each layer of the packaging material is all polypropylene-based resin, it is also excellent in recyclability, and the adhesive is used. Even if it is not used, it is possible to provide a packaging material that can adhere each layer by heat fusion and is excellent in folding resistance and heat resistance.

  Moreover, according to the packaging material which concerns on this invention of Claim 12 mentioned above, since the film (C) was each laminated | stacked and bonded via the foam sheet (B) and the reinforcing material (D) on both surfaces of the foam sheet (A), It is possible to provide a packaging material that has excellent buffering properties on both sides and has an effect of preventing tearing.

  Moreover, according to the packaging material which concerns on this invention of Claim 13 mentioned above, since the layer which consists of foam sheets (A) was 50 weight% or more by weight ratio with respect to the whole packaging material, rigidity and buffering property as a whole further It is possible to provide a packaging material excellent in balance.

  Hereinafter, embodiments of the packaging material according to the present invention will be described in detail.

  As shown in FIG. 1, the packaging material according to the present invention has a polyolefin resin foam sheet (B) laminated and bonded to at least one surface of the polyolefin resin foam sheet (A), and further the outer surface of the foam sheet (B). On the side, a polyolefin resin film (C) containing a polymer type antistatic agent is laminated and bonded, or as shown in FIG. 2, the foam sheet (B) and the film (C) Further, the reinforcing material (D) is laminated and bonded between the two. The foamed sheet (B), the film (C), etc. may be laminated and bonded to at least one surface of the foamed sheet (A) as shown in FIG. 1 and FIG. It is preferable that the two are laminated and adhered to each other because a packing material having excellent buffering properties on both sides and having an effect of preventing tearing can be provided.

The apparent density of the polyolefin resin foam sheet (A) is 60 to 600 kg / m ³ . The apparent density of the foam sheet (A) is determined by the balance between the weight and rigidity required for the packaging material. If the apparent density is too low, the rigidity is insufficient, and the packaging material is given rigidity. The intended purpose cannot be achieved. Conversely, if the density is too high, the lightness becomes insufficient. Considering the balance between such lightweight and rigid, the apparent density of the foam sheet (A) is preferably 90~300kg / m ^3, more preferably 100~180kg / m ^3.

  Moreover, the thickness of the said foam sheet (A) is 0.5-10 mm. If the thickness of the foam sheet (A) is too thin, the rigidity as a packaging material will be insufficient. Conversely, if the thickness is too large, not only will the workability and lightness be reduced, but the packaging space for storing the product will decrease. As unsuitable. From this viewpoint, the thickness of the foam sheet (A) is preferably 1 to 5 mm.

The apparent density of the polyolefin resin foamed sheet (B) is 15 to 90 kg / m ³ (however, less than the apparent density of the foamed sheet (A)). The apparent density of the foam sheet (B) is determined by the cushioning performance required for the packaging material, but if the apparent density is too low, the foam sheet (B) becomes too flexible and exhibits the cushioning performance. I can't. On the other hand, if the apparent density is too high, the cushioning performance of the foam sheet (B) is insufficient. From this point of view, the apparent density of the foam sheet (B) is preferably 20~60kg / m ^3, more preferably 25~50kg / m ^3.

  Moreover, the thickness of the said foam sheet (B) is 0.3-3 mm. If the thickness of the foamed sheet (B) is too thin, sufficient buffer performance cannot be obtained. On the other hand, when the thickness is too thick, the buffering performance is sufficient, but the packaging material is not only in excess quality but also inferior in handleability and lightness. From this viewpoint, the thickness of the foam sheet (B) is preferably 0.5 to 2 mm.

The polyolefin resin film (C) containing the polymer type antistatic agent preferably has a thickness of 0.02 mm or more. If the thickness of the film (C) is too thin, even if the reinforcing material (C) is present, there is a possibility that a sufficient tear prevention effect cannot be obtained. However, if it is too thick, the tear prevention effect is sufficient, but the lightness is greatly reduced and the buffering property is reduced. Therefore, the thickness of the film (C) is preferably 0.2 mm or less. More preferably, it is 1 mm or less. This film (C) contains a polymer type antistatic agent, and the surface resistivity of the film (C) is preferably 1 × 10 ⁸ to 1 × 10 ¹³ (Ω). It is possible to impart a semi-permanent antistatic effect to the packaging material without contaminating the package and hardly affected by the atmospheric temperature and humidity.

The polymer antistatic agent contained in the film (C) has a surface resistivity of less than 1 × 10 ¹² (Ω), preferably less than 1 × 10 ¹¹ (Ω), more preferably 1 × 10 ¹⁰ (Ω). It consists of less than resin. Specifically, an ionomer resin containing an alkali metal selected from the group consisting of potassium, rubidium and cesium as a metal ion, or a resin mainly composed of a hydrophilic resin such as polyether ester amide or polyether is preferable. . In addition, the polymer antistatic agent improves compatibility with the polyolefin resin constituting the film (C), provides an excellent antistatic effect, and suppresses deterioration in physical properties due to the addition of the antistatic agent. In order to obtain the effect, it is preferable to use a resin obtained by block copolymerization of a polyolefin resin. Further, the average molecular weight of the polymer antistatic agent used in the present invention is preferably 2000 or more, more preferably 2000 to 100,000, still more preferably 5000 to 60000, and particularly preferably 8000 to 40000. It is distinguished from an antistatic agent consisting of an agent. The melting point of the polymer type antistatic agent is preferably 70 to 270 ° C., more preferably 80 to 230 ° C., and particularly preferably 80 to 200 ° C. from the viewpoint of expression of the antistatic function. Examples of such polymer type antistatic agents are commercially available under the trade names of “SD100” manufactured by Mitsui DuPont Polychemical Co., Ltd. and “Pelestat 300” manufactured by Sanyo Chemical Industries Co., Ltd. Is mentioned. The above-mentioned polymer antistatic agents can be used alone, but they may be used in combination. In general, the polymer-type antistatic agent is blended in a polyolefin resin in an amount of 5 to 20% by weight. The surface resistivity can be adjusted in the range of 1 × 10 ⁸ to 1 × 10 ¹³ (Ω). As the film (C), either a single layer film or a multilayer film can be used. When the film is a multilayer film, the surface resistivity of at least one surface may be in the above range.

  As the reinforcing material (D) laminated and bonded as necessary between the foam sheet (B) and the film (C), woven fabric, nonwoven fabric, stretched resin film, fiber reinforced resin film, metal foil or Paper or the like can be used, but in particular, when a woven fabric, a nonwoven fabric, a stretched resin film, or a fiber reinforced resin film using a thermoplastic resin as a base resin is used, the entire packaging material is composed of a thermoplastic resin. If the woven or non-woven fabric made of stretched polyolefin resin is used, the entire packing material will be made of polyolefin resin, and it will be more recyclable. In addition, it is preferable because it has better buffering properties, is harder to tear, and has high tear strength and surface impact. Among them, it is particularly preferable that the reinforcing material (D) is woven or bonded so that the stretching direction is substantially orthogonal, since it has excellent tear strength without directionality. Such commercially available products that can be suitably used as the reinforcing material (D) include, for example, “Warif (registered trademark)” manufactured by Nippon Steel Plast Co., Ltd. and “Meltack (manufactured by Ebara Industries Co., Ltd.). Registered trademark) ”and the like.

The basis weight of the reinforcing material (D) is preferably 10 to 50 g / m ² . When the basis weight of the reinforcing material (D) is in the above range, the packaging material is excellent in the balance between the tear prevention effect and the light weight. From this viewpoint, the basis weight of the reinforcing material (D) is more preferably 15 to 30 g / m ² .

  When the reinforcing material (D) is laminated and bonded between the foamed sheet (B) and the film (C), the effect of preventing tearing is sufficient, so the thickness of the film (C) can be increased. Even if the thickness of the film (C) is 0.03 to 0.1 mm, a sufficient tear preventing effect can be obtained and the packaging material can be made more lightweight.

  The polyolefin resin forming the foam sheet (A), the foam sheet (B), the film (C) and the reinforcing material (D) is a resin having an olefin component unit of 50 mol% or more. Examples of the polyolefin resin include a polyethylene resin and a polypropylene resin.

  Examples of the polyethylene resin include resins having an ethylene component unit of 50 mol% or more, such as high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer. Polymer, ethylene-propylene-butene-1 copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-4-methylpentene-1 copolymer, ethylene-octene-1 copolymer Examples thereof include a polymer and a mixture of two or more thereof.

  Moreover, as said polypropylene resin, the copolymer with components, such as a propylene homopolymer or another olefin copolymerizable with propylene, is mentioned. Examples of other olefins copolymerizable with propylene include ethylene, 1-butene, isoptylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1 Examples thereof include α-olefins having 4 to 10 carbon atoms such as -heptene and 3-methyl-1-hexene. The copolymer may be a random copolymer, a block copolymer, or the like, and may be not only a binary copolymer but also a ternary copolymer. In addition, it is preferable that the other component copolymerizable with the propylene in the said copolymer is contained in the ratio of 25 weight% or less, especially 15 weight% or less. The lower limit of the content of the other copolymerizable components is generally 0.3% by weight in consideration of the reason for selecting the copolymer. These polypropylene resins can be used in combination of two or more.

  The polyolefin resin used in the present invention includes a styrene resin such as polystyrene, an ethylene propylene rubber, etc. within a range that does not impair the respective purposes and effects of the foam sheet (A) and the foam sheet (B) of the present invention. Butene-based resins such as elastomer and polybutene can be added. In this case, the amount added is preferably 40 parts by weight or less, more preferably 25 parts by weight or less, and particularly preferably 10 parts by weight or less, based on 100 parts by weight of the polyolefin resin. In addition, the polyolefin-based resin includes, for example, a nucleating agent, an antioxidant, and a heat stabilizer as long as the purpose and effect of the foamed sheet (A) and foamed sheet (B) of the present invention are not impaired. , Functional additives such as weathering agents, ultraviolet absorbers and flame retardants, inorganic fillers and the like may be contained.

As the base resin of the foamed sheet (A), among the above-described polyolefin resins, those having a main component of polyethylene having a density of 940 kg / m ³ or more are preferable, and in particular, polyethylene having a density of 940 kg / m ³ or more. (X) and a mixture of polyethylene (Y) having a density of less than 940 kg / m ³ and a weight ratio of the polyethylene (X) to the polyethylene (Y) of 50:50 to 90:10, The foam sheet is preferable because it has a smooth surface, good appearance, and excellent rigidity. From this viewpoint, the weight ratio of the polyethylene (X) and the polyethylene (Y) is more preferably 50:50 to 80:20. In addition, having a density of 940 kg / m ³ or more as a “main component” means that the polyethylene content is 50% by weight or more of the total weight of the base resin constituting the foam sheet (B). .

Examples of the polyethylene (X) having a density of 940 kg / m ³ or more include so-called linear polyethylene, and specifically, high-density polyethylene and the like. The density of the polyethylene (X) is more preferably 950 kg / m ³ or more, and further preferably 955 kg / m ³ or more, from the viewpoint of further increasing the rigidity of the foamed sheet (A). Examples of the polyethylene (Y) having a density of less than 940 kg / m ³ include so-called low density polyethylene, linear low density polyethylene, linear ultra-low density polyethylene, and the like. Among them, a foam sheet having a low apparent density ( A low density polyethylene having good foaming properties such as A) is preferred. The lower limit of the density of the polyethylene (Y) is usually about 910 kg / m ³ .

As the base resin of the foam sheet (B), among the above-mentioned polyolefin resins, those having a density of polyethylene less than 940 kg / m ³ as a main component are preferable. Specifically, it is preferable to use low-density polyethylene, linear low-density polyethylene, etc., and since foamability is good and the foamed sheet is excellent in buffering properties, low-density polyethylene is more preferable. From this viewpoint, the density of the low density polyethylene is more preferably 930 kg / m ³ or less, and further preferably 925 kg / m ² or less. The lower limit of this density is approximately 890 kg / m ³ . The phrase “the main component” means a polyethylene having a density of less than 940 kg / m ³ means that the polyethylene content is 50% by weight or more of the total weight of the foamed sheet (B).

As the base resin of the film (C) containing the polymer type antistatic agent, among the above-mentioned polyolefin resins, linear low density polyethylene having a density of 920 kg / m ³ or more and less than 940 kg / m ³ , or a density It is preferable to use high-density polyethylene of 940 kg / m ³ or more because the rigidity of the film (C) is high and a packaging material that is more excellent in preventing tearing can be provided. From this viewpoint, the density of the high-density polyethylene used as the base resin of the film (C) is more preferably 950 kg / m ³ or more.

As the base resin of the reinforcing material (D) which is laminated and adhered as necessary between the foam sheet (B) and the film (C), the density is 940 kg / m among the above-described polyolefin resins. ^Three or more polyethylenes are preferred. Specifically, it is preferable to use high-density polyethylene, and high-molecular-weight polyethylene is superior in mechanical strength compared to other polyethylenes, and therefore has an excellent tear prevention effect when used as a surface layer of a packaging material. In addition, the upper limit of the density of polyethylene used as the base resin of the reinforcing material (D) is approximately 970 kg / m ³ .

  As mentioned above, when all the base resin constituting each layer of the packaging material is made of polyethylene resin, it is excellent in recyclability, and each layer is formed by heat fusion without using an adhesive. It is preferable because a packaging material that can be bonded and has excellent cold shock resistance can be provided. Similarly, it is also preferable that the base resin constituting each layer of the packing material is all polypropylene-based resin. In this case, it is also excellent in recyclability, and heat fusion is performed without using an adhesive. Each layer can be adhered by wearing, and a packaging material excellent in folding resistance and heat resistance can be provided.

  The foamed sheet (A) and the foamed sheet (B) can be produced by an extrusion foaming method in which the base resin and the foaming agent described above are melt-kneaded in an extruder and then extruded and foamed from the extruder. The foaming agent is appropriately selected from known organic foaming agents such as butane, inorganic foaming agents such as carbon dioxide, or decomposition-type foaming agents such as baking soda, which are used in the production of this type of foam or foam sheet. Can be used. The film (C) containing a polymer antistatic agent can be produced by melt-kneading the above-described base resin and polymer antistatic agent in an extruder and then extruding from the extruder. . The reinforcing material (D) can be produced, for example, by continuously laminating and stretching stretch-reinforced polyolefin split fibers vertically and horizontally.

  The packaging material according to the present invention is obtained by laminating and bonding the above-described foamed sheet (A), foamed sheet (B) and the like as shown in FIG. 1 or FIG. As a method of laminating and bonding, any conventionally known method can be adopted, and examples thereof include a method using an adhesive, a method for melting and pressing a surface by heat, and a method for laminating a molten resin. For example, when the foamed sheet (A) and the foamed sheet (B) have heat-bonding properties, the surface of the sheet can be bonded with a hot roll or hot air. A method of heating and melting the surface to perform pressure bonding, a so-called thermal laminating method, and laminating a foam sheet (B) that does not have heat fusion with the foam sheet (A) on the foam sheet (A). In this case, by applying a general adhesive such as a heat-sensitive adhesive or a pressure-sensitive adhesive in advance to the adhesive surface of the foam sheet (B), lamination by a heat laminating method can be performed. Examples of heat-sensitive adhesives include olefin-based heat-sensitive adhesives composed of copolymers of olefin and vinyl acetate, acrylic acid, maleic anhydride, etc., and pressure-sensitive adhesives include acrylic and rubber-based pressure-sensitive adhesives. Can be mentioned. Of course, even when both sheets have heat-fusibility, both sheets can be bonded using an adhesive. Also, the adhesion between the foam sheet (B) and the film (C), the adhesion between the foam sheet (B) and the reinforcing material (D), and the adhesion between the reinforcing material (D) and the film (C) What is necessary is just to select suitably from said lamination | stacking method according to the presence or absence of the heat-fusion property with each other layer of each layer.

  As for the packing material which concerns on this invention, 1-10 mm is preferable as total thickness of the said foamed sheet (A) laminated | stacked and bonded, a foamed sheet (B), etc. If the total thickness is too thin, the rigidity or shock-absorbing property is lowered. If the total thickness is too thick, not only the workability and light weight are lowered, but also the storage space for storing the product is reduced. From this viewpoint, the thickness of the packaging material is more preferably 2 to 7 mm. Moreover, the packaging material which concerns on this invention provides the packaging material excellent in the balance of rigidity and buffer property that the weight ratio of the layer which consists of the said foamed sheet (A) with respect to the whole is 50 weight% or more. This is preferable because it can be performed. From this viewpoint, the weight ratio of the layer made of the foamed sheet (A) is more preferably 60% by weight or more.

In addition, the thickness of each layer of the packaging material described above is obtained by enlarging a cross section of the packaging material with a microscope or the like, measuring the thickness of each layer at any 10 locations, and arithmetically averaging the measured values for each layer. In addition, the apparent density of each layer of the packing material is obtained by cutting out the layer to be measured so that other layers do not enter, and obtaining the volume of the test piece by the submerging method, etc. Is divided by the volume of the test piece, and the unit is converted to kg / m ³ . In addition, the surface resistivity in the present specification is that the condition of the test piece is adjusted for 24 hours in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50%. It is a value measured under conditions.

  Hereinafter, although the Example of the packing material which concerns on this invention is described, this invention is not limited to the following Example at all.

The 7-layer packing material shown in FIG. 3 was produced.
The following were used for each layer.
-Foam sheet (A)
A mixture of 85% by weight of “PF814” (propylene homopolymer) manufactured by Sun Allomer Co., Ltd. and 15% by weight of “Q100F” (polyolefin rubber) manufactured by Sun Allomer Co., Ltd. is used as a base resin. A foam sheet having a density of 112 kg / m ³ and a thickness of 3.0 mm was produced.
・ Foam sheet (B)
Sumitomo Chemical Co., Ltd. "F102" (low-density polyethylene, density 922 kg / m ³⁾ and the base resin, the density 30kg / m ³ apparent by extrusion foaming method, to produce a foamed sheet having a thickness of 1.0 mm.
・ Reinforcing material (D)
“Warifu HS24” (polyethylene stretched tape non-woven fabric, basis weight 35 g / m ² , thickness 0.10 mm) manufactured by Shin Nippon Plast Co., Ltd. was used.
・ Antistatic film (C)
"STAT-3S" for laminates manufactured by Technostat Kogyo Co., Ltd. (Multilayer film of linear low density polyethylene film (20 μm) containing polymer type antistatic agent and linear low density polyethylene film (30 μm)) And a surface resistivity of 9 × 10 ⁹ Ω on the surface of the antistatic layer side film).

Lamination adhesion of each layer was performed by the following method.
The foamed sheet (A) and the foamed sheet (B) were bonded using an adhesive. The foamed sheet (B) and the reinforcing material (D) and the reinforcing material (D) and the antistatic film (C) were bonded by a heat laminating method. The antistatic film (C) was bonded such that the antistatic agent layer was on the surface side of the packaging material.

The obtained packing material has a thickness of 5.3 mm and a basis weight of 562 g / m ² , has the same rigidity and shock-absorbing properties as before, has antistatic performance, and has a surface that is difficult to break. It was.

1 is a conceptual longitudinal sectional view showing an embodiment of a packaging material according to the present invention. It is the conceptual longitudinal cross-sectional view which showed other embodiment of the packing material which concerns on this invention. It is the notional longitudinal cross-sectional view which showed one Example of the packing material which concerns on this invention.

Explanation of symbols

A Foamed sheet (A)
B Foamed sheet (B)
C Antistatic film (C)
D Reinforcement material (D)

Claims (13)

Thickness 0.5 to 10 mm, on at least one surface of the polyolefin-based resin foam sheet apparent density 60~600kg / m ³ (A), thickness 0.3 to 3 mm, polyolefin-based resin foam sheet apparent density 15~90kg / m ³ (B) [However, the apparent density of the foam sheet (B) is less than the apparent density of the foam sheet (A). In a packaging material that is laminated and bonded,
A packaging material, wherein a polyolefin-based resin film (C) containing a polymer antistatic agent is laminated and adhered to the outer surface side of the foamed sheet (B).   A reinforcing material (D) is laminated and bonded between the foam sheet (B) and the film (C), and the thickness of the film (C) is 0.03 to 0.1 mm. The packaging material according to claim 1.   The packing material according to claim 2, wherein the reinforcing material (D) is a woven fabric, a non-woven fabric, a stretched resin film, or a fiber reinforced resin film using a thermoplastic resin as a base resin.   The packing material according to claim 2, wherein the reinforcing material (D) is a woven fabric or a nonwoven fabric made of a stretched polyolefin resin. The basis weight of the reinforcing member (D), characterized in that a 10 to 50 g / m ^2, the packaging material according to any of claims 2-4. It said foam sheet (A) base resin constituting the, characterized in that the main component density 940 kg / m ³ or more polyethylene packaging material according to claim 1. The base resin constituting the foam sheet (A) is a mixture of polyethylene (X) having a density of 940 kg / m ³ or more and polyethylene (Y) having a density of less than 940 kg / m ³ , and the polyethylene (X) The packing material according to any one of claims 1 to 6, wherein a weight ratio with said polyethylene (Y) is 50: 50-90: 10. The packaging material according to claim 1, wherein the base resin constituting the foamed sheet (B) is polyethylene having a density of less than 940 kg / m ³ . Base resin constituting the film (C), characterized in that the density 920 kg / m ³ or more 940 kg / m ³ of less than linear low density polyethylene, or density 940 kg / m ³ or more polyethylene, wherein The packing material in any one of claim | item 1 -8.   The base resin constituting the foam sheet (A), the foam sheet (B), the film (C) and the reinforcing material (D) are all polyethylene-based resins. The packaging material according to any one of 9.   The base resin that constitutes the foam sheet (A), the foam sheet (B), the film (C), and the reinforcing material (D) are all polypropylene-based resins. The packaging material according to any one of 5.   The film (C) is laminated and bonded to both surfaces of the foam sheet (A) via the foam sheet (B) and the reinforcing material (D), respectively. The packaging material according to any one of the above.   The weight ratio of the layer which consists of the said foam sheet (A) with respect to the said whole packing material is 50 weight% or more, The packing material in any one of Claims 1-12 characterized by the above-mentioned.

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