JP4311081B2 - Film-like cushioning material - Google Patents

Description

【００５６】
【表２】

【００５７】
【発明の効果】
本発明により、効率よく包装容器内部の水分を吸湿して乾燥状態あるいは調湿状態を保持し、かつ柔軟性と剛性といった相反する物性を有し、さらには優れた弾性回復性を有するフィルム状の緩衝材を提供することができる。 本発明のフィルム状の緩衝材は、吸湿性を有する無機化合物を配合することで乾燥機能や調湿機能を有するだけでなく、緩衝機能を有し、緩衝用フィルム等として包装用部材としての用途などに使用される。また、本発明のフィルム状の緩衝材は、従来の小袋状吸湿剤やタブレット状吸湿剤と異なり誤飲、誤食の問題もなく、さらに粘着剤を設けたこれらの乾燥剤と異なり、容器への装着も煩雑ではない。さらに、本発明のフィルム状の緩衝材は、緩衝用フィルム等として包装用部材のみならず、各種基材への積層も可能であることから、軟包装剤への展開など応用範囲も広い。本発明のフィルム状の緩衝材は、近年求められる内容物の保護性能（吸湿による変質や内容物の破損など）に優れるものである。
【図面の簡単な説明】
【図１】 本発明の一実施例としてのフィルム状の緩衝材の構成を示す断面図である。
【図２】 本発明の一実施例としてのフィルム状の緩衝材を剛性・柔軟性を有する包装用部材として用いた例を説明する説明図である。
Ａは、振動により内容物が動いても、緩衝機能を維持している例を示す。
Ｂは、振動により内容物が動き、緩衝機能が失われる例を示す。
【図３】 本発明の一実施例としてのフィルム状の緩衝材を弾性回復性を有する包装用部材として用いた例を説明する説明図である。
Ａは、内容物が減少した際、緩衝材が拡大し、ヘッドスペースを補充する例を示す。
Ｂは、内容物が減少しても、緩衝材が元の形状を維持し、ヘッドスペースを補充できない例を示す。
【図４】 本発明のフィルム状の緩衝材の吸湿性を評価する評価方法の一例を説明する説明図である。
【符号の説明】
ａ：吸湿フィルム
ａ−１：吸湿性を有する無機化合物を配合したポリオレフィン系樹脂（Ａ）
ａ−２：ポリオレフィン系樹脂（Ｂ）
ａ−３：吸湿性を有する無機化合物
ａ−４：発泡部
ｂ：容器
ｃ：タブレット状内容物
ｄ：湿度センサー[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a film-like cushioning material containing an inorganic compound having a hygroscopic function. More specifically, the inside of a packaging container is kept dry or conditioned by moisture absorption of a hygroscopic agent, and has flexibility and rigidity. Concerning film-like cushioning material having contradictory physical properties, and having excellent elastic recovery properties, the film-like cushioning material itself is used as a packaging film as a cushioning film that absorbs the impact on the contents. It is used.
[0002]
[Prior art]
  In the field of packaging business for packaging various contents, the keywords of “package” or “packaging” can include the following contents.
(1) “Display effects” such as giving consumers purchase awareness and presenting dangers.
(2) “Content resistance” so that the package itself is not affected by the filled content itself.
(3) “Protection of contents” against external stimuli.
[0003]
  These keywords are further subdivided and expanded to fine required quality. Among them, the protection of contents from oxygen and moisture is particularly attracting attention in terms of “protection of contents”. In recent years, in particular, in the fields of food, industrial products, medical / pharmaceutical fields, etc., the protection of contents against oxygen and moisture has been regarded as important. As the background, there are oxygen content decomposition and alteration due to oxidation, and moisture content alteration due to moisture absorption and hydrolysis.
[0004]
  Various methods have been studied in order to prevent the contents from being altered by oxygen or moisture. One of them is to design a package using a material having an oxygen barrier or moisture barrier property. In terms of moisture barriers, the most common film is one that uses moisture-proof polyolefin-based resins, or that has been given moisture-proof properties by providing a polyvinylidene chloride-based coating layer on these polyolefin, polyester, or polyamide films. Is.
[0005]
  The packaging body using these moisture barrier base materials has spread to various uses because of its high moisture barrier property. However, since these moisture barrier base materials use chlorinated polymers, alternatives are being studied. In addition, some contents may be deteriorated by slight humidity and moisture in the head space, and not only the moisture barrier property from the outside of the packaging container but also the humidity and moisture in the head space are to be removed. Needs are emerging. In addition, depending on the contents, there is a case where an appropriate humidity environment is required. In particular, the capsule-shaped contents are sometimes required to have a humidity control function in the container.
[0006]
  In order to answer these needs, a sachet or tablet-like moisture absorbent is mixed with the contents, or a pouch-like or tablet-like moisture absorbent with adhesive is attached to the inside of the cap or lid. For example, attempts have been made to adjust the humidity by removing moisture in the container or controlling the amount of moisture. However, sachets or tablets of hygroscopic agent have problems of accidental ingestion and accidental eating, and there are problems such as complicated installation process when sticking inside caps and lids using adhesive. ing.
[0007]
  From such a background, containers that have been provided with hygroscopicity by kneading a hygroscopic agent into various containers have been developed. These techniques are already known techniques. In particular, a hygroscopic container in which a hygroscopic agent is blended with the polymer described in Patent Document 1 forms an injection-molded container by blending a hygroscopic agent and a channel structure forming agent with a thermoplastic resin. The mechanism is that the hygroscopic agent is selectively dispersed in the phase composed of the channel structure forming agent, and the local concentration distribution and moisture absorption are used to gradually generate fine cracks starting from the channel unit portion. Hygroscopicity is improved by using as a passage for moisture. However, although this container also has a moisture absorption capability, the occurrence of cracks is a concern about the influence on the strength physical properties of the container. Further, since the channel structure forming agent uses a water-soluble low molecular weight compound, it has problems such as discoloration due to moisture absorption and bleeding. Furthermore, for contents such as pharmaceuticals that extremely dislike moisture absorption, many packaging containers are glass containers, and there is a limit even if a moisture absorption function is imparted to a plastic container.
[0008]
[Patent Document 1]
  US Pat. No. 6,214,255
[0009]
[Problems to be solved by the invention]
    The present invention takes the above-mentioned circumstances into consideration, efficiently absorbs moisture inside the packaging container to maintain a dry state or a humidity-controlled state, and has contradictory physical properties such as flexibility and rigidity. It is an object of the present invention to provide a film-like cushioning material that has excellent elasticity recovery and is used for a packaging member such as a cushioning film.
[0010]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention provides a buffer in the form of a film comprising a multilayer film including a polyolefin resin composition layer (A) containing an inorganic compound having a moisture absorption function. In the material, a polyolefin resin layer (B) is provided on both sides of the polyolefin resin composition layer (A), and the density of the polyolefin resin serving as a base resin of the polyolefin resin composition layer (A) is d._AD_A≦ 0.930g /cm ³ And the density of the polyolefin resin of the polyolefin resin layer (B) is d_BD_B≧ 0.910 g /cm ³ And d_A<D_BAnd at least one of the polyolefin resin composition layer (A) or the polyolefin resin layer (B) is foamed.
[0011]
[0012]
  The invention according to claim 2 is characterized in that the thickness of the polyolefin resin layer (A) is t._AThe total thickness of the polyolefin resin layer (B) is t_BT_A≧ t_BThe film-like cushioning material according to claim 1, wherein the relationship is satisfied.
[0013]
  The invention according to claim 3 is that the polyolefin resin composition layer (A) comprises a resin composition containing 1 to 100 parts by weight of an inorganic compound having a hygroscopic function with respect to 100 parts by weight of the polyolefin resin. The film-like cushioning material according to claim 1 or 2.
[0014]
  The invention according to claim 4 is a periodic table in which at least one of the polyolefin resin or the polyolefin resin (B) serving as the base resin of the polyolefin resin composition layer (A) is a cyclopentadienyl derivative. An ethylene-α olefin copolymer obtained by using a single site catalyst consisting of methylaluminoxane, if necessary, or a complex consisting of a group III, IV, V, VI, IX, X transition metal atom or the metal complex However, α olefin: C3-C8 composed of propylene, butene-1, hexene-1, octene-1, 4-methylpentene-1, or a higher α olefin of C9 or higher) is included as an essential component. It is a film-form shock absorbing material of any one of Claims 1-3.
[0015]
  According to a fifth aspect of the present invention, the inorganic compound having a moisture absorption function has a moisture absorption capacity of at least 10% of its own weight at 40 ° C.-90% relative humidity, and the inorganic compound contains zeolite, calcium oxide, chloride. It is selected from at least one of sulfate compounds such as calcium and magnesium sulfate, alumina, activated carbon, clay mineral, and silica gel. It is.
[0016]
  In the invention according to claim 6, a foaming agent is blended in at least one of the polyolefin-based resin composition layer (A) or the polyolefin-based resin layer (B), and foamed within a range of 1 to 50 times the expansion ratio. It is a film-form shock absorbing material of any one of Claims 1-5 characterized by these.
[0017]
[0018]
DETAILED DESCRIPTION OF THE INVENTION
  As a result of investigating the contents that require moisture-absorbing drying and moisture-control functions regardless of whether they are plastic containers or glass containers, especially for medical drugs that are cited as contents that dislike moisture absorption, in the case of tablet-like contents Since there is a concern about breakage of the tablet-like contents due to vibration of the container, etc., a film-like cushioning material is often attached together with the contents. In addition, since such a content is filled in a reclose type container, the content is reduced and the head space is increased at the same time. An increase in headspace means that the amount of moisture contained in the air increases. When repeatedly using tablet-like contents or powder-like contents that adhere due to moisture absorption, reduce the headspace as much as possible. I want to go. As a result of intensive studies from such a viewpoint, it is possible to prevent damage to the contents and reduce the head space by giving a moisture absorbing function to the packaging member itself such as the above-described film-like cushioning material. confirmed.
[0019]
  Hereinafter, the present invention will be described in detail. The film-like cushioning material of the present invention is made from the above-described viewpoint.
[0020]
  First, as the polyolefin-based resin composition layer (A) containing an inorganic compound having a hygroscopic function, the saturated water absorption amount of the hygroscopic inorganic compound in an atmosphere of 40 ° C. and 90% relative humidity is at least 10% or more with respect to its own weight. It is preferable. Below that, the moisture absorption performance is poor. Such a material is selected from at least one of zeolite, calcium oxide, calcium chloride, zinc oxide, barium titanate, sulfate compounds such as magnesium sulfate and alunite, alumina, activated carbon, clay mineral, and silica gel. .
[0021]
  These inorganic compounds having a hygroscopic function can be properly used according to the intended function. For example, if you want to give the container a drying function, use inorganic compounds such as zeolite and calcium oxide. If you want to give a humidity control function, use sulfate compounds such as magnesium sulfate and alumite, alumina, activated carbon, and clay minerals. It is preferable to use silica gel or the like.
[0022]
  As a compounding quantity of this inorganic compound which has a moisture absorption function, 1-100 weight part of said inorganic compounds which have a moisture absorption function with respect to 100 weight part of polyolefin-type resin are mix | blended. When the amount is less than 1 part by weight, the hygroscopic ability is inferior. When the amount is more than 100 parts by weight, the hygroscopic function is preferable, but the strength physical properties and economical efficiency as the composition are inferior. These inorganic compounds may be pretreated (surface treatment) in advance for improving dispersibility. In addition, the blending amount in the composition is also important, but focusing on the hygroscopic ability, the absolute amount such as how much the inorganic compound having the hygroscopic function is contained in the closed system including the container is a point. Therefore, in consideration of the relationship between the amount of moisture converted from the container volume in an atmosphere at 40 ° C. and the number of opening and closing, it is preferable to blend an inorganic compound having a moisture absorption function that can take in moisture. These relationships are shown as follows.
  α: amount of hygroscopic inorganic compound in the container (g)
  β: Absorption amount (%) of the hygroscopic inorganic compound with respect to its own weight under 40 ° C.-90% relative humidity
  γ: Moisture content (g) at 40 ° C.-100% relative humidity converted from the container volume
  δ: Number of opening and closing ... unit times
  δ × α × β / 100 ≧ γ
[0023]
    A polyolefin-based resin layer (B) is provided on both sides of the polyolefin-based resin composition (A) containing the inorganic compound having a moisture absorption function, and the polyolefin-based resin serving as the base of the polyolefin-based resin composition layer (A) at that time Resin density (d_A) Is d_A≦ 0.930g /cm ^Three The density of the polyolefin resin layer (B) (d_B) Is d_B≧ 0.910g/ Cm ^Three It is preferable to set so that_AAnd d_BRelationship is d_A<D_BTo have a relationship. This density relationship can be a factor for controlling the contradictory functions of rigidity and flexibility of the film-like cushioning material. In particular, it is necessary to sandwich the polyolefin resin composition (A) from both sides with the polyolefin resin (B) having the above-described relationship.
[0024]
  d_A> D_BIf it is, rigidity cannot be imparted. D_A> 0.930 g / cm^ThreeWhen it is, flexibility cannot be provided. Furthermore, since a high content of inorganic compound is blended, there is a risk of cracking with a slight stress. On the other hand, d_B<0.910 g / cm^ThreeIf it is, the adhesiveness of the resin itself is improved, and when the film is crumpled, the films adhere to each other and may not return to the original shape. In the case of powdered contents, the contents may adhere to the film. From this point of view, d_A≦ 0.930 g / cm^Three, Preferably ≦ 0.920 g / cm^Three, More preferably ≦ 0.910 g / cm^ThreeAnd d_B≧ 0.910 g / cm^Three, Preferably ≧ 0.920 g / cm^Three, Preferably ≧ 0.930 g / cm^ThreeIt is. By satisfying these environments, it is possible to impart contradictory functions of rigidity and flexibility to the film without causing adhesion between films and contents.
[0025]
  Furthermore, in terms of rigidity and flexibility, the relationship between the thicknesses of the layers is also important. As a result of intensive studies, the thickness of the polyolefin resin composition (A) (t_A) And polyolefin resin layer (B) total thickness (t_B) Is t_A≧ t_BIf this relationship is not satisfied, rigidity and flexibility cannot be balanced.
[0026]
  The rigidity here is the hardness of the film, and this hardness is influenced by the content holding force when used as a cushioning material shown in FIG. That is, when the contents are moved by vibration, the contents are easily moved if the film-like cushioning material is not rigid, and in the worst case, the contents are damaged (see FIG. 2-B). In this case, the ability as a buffer function is not expressed, and it is preferable to maintain the shape as a film-like buffer material even if the contents are moved by vibration as shown in FIG. On the other hand, the flexibility is literally the softness of the film, and this softness is also a function required for the film-like cushioning material. For example, even if the head space is small as shown in FIG. 2, a large size film must be inserted. Furthermore, it is desirable that a film-like cushioning material replenishes the volume corresponding to the head space as much as possible even when the head space is increased, assuming that the contents are reduced. However, when the contents are fully filled in the container, the cushioning material for this head space must be pushed into a small head space. In that sense, flexibility is necessary.
[0027]
  Furthermore, in addition to the balance between rigidity and flexibility described above, the film-like cushioning material is imparted with the elastic stress recovery property of the material described later, that is, a property that deforms when stress is applied and returns to its original state when released. If possible, the above-described effect can be expressed more. This content is illustrated in FIG. FIG. 3-B shows a film-like cushioning material when there is no elastic recovery force. The shape is maintained by being held down by the contents, and the head space is increased by reducing the contents. On the other hand, when it has elastic recovery force, the stress that the crushed film-like cushioning material was pressed by the contents is released by reducing the contents, trying to return the shape to the original shape The power to do is working. By applying the elastic recovery force in this way, even if the contents are reduced and the head space is increased, the buffer film expands due to the release of stress and replenishes the head space (see FIG. 3-A). In that sense, not only the above parameters, but also one or both of the polyolefin resin and the polyolefin resin (B), which are the main components of the polyolefin resin composition layer (A), are the period of the cyclopentadienyl derivative. In accordance with ASTM D1238 obtained by using a single site catalyst consisting of a complex consisting of Group III, IV, V, VI, IX, and X transition metal atoms and methylaluminoxane as necessary for the above metal complex It is mentioned that the base resin is an ethylene-α-olefin copolymer having a melt index (MI) in the range of 0.1 to 200.
[0028]
  Examples of such a catalyst include a single site catalyst (Kaminsky catalyst) obtained by adding methylaminoxan to bis (cyclopentadienyl) zirconium chloride and derivatives thereof. Metals, especially titanium, zirconium, hafnium, etc.IVGroup transition metals are used, but are not limited thereto. The catalyst has a structure in which a transition metal is introduced into two bulky cyclopentadienyl groups. By using a titanium-based geometrically constrained catalyst, C6, C8, or higher α-olefins of C9 or higher can be obtained. It is possible to introduce.
[0029]
  The advantages of using such a single-site catalyst are as follows.
(1): Molecular weight distribution is narrow.
(2): The introduction position of the comonomer is easy to control.
(3): Since there are many tie molecules between lamellae, it has excellent strength against tearing.
It is.
(4): Flexibility can be imparted.
(5): Excellent resistance to stress cracking.
[0030]
  Moreover, in the balance of rigidity and flexibility described above, the density of 0.930 g / cm is obtained with this ethylene-α-olefin copolymer.^ThreeHereinafter, particularly the density region is 0.850 to 0.925 g / cm.^ThreeIn the case of those having a range of polyolefin elastomer or plastomer, in particular, if the flexural modulus is 250 MPa or less, it is not only preferable in terms of strength properties but also excellent in elastic recovery.
[0031]
  Furthermore, by using a titanium-based geometrically constrained catalyst, it is possible to introduce not only the comonomer distribution position but also higher C9 or higher α-olefin (product in ionic polymerization) as a comonomer. Nevertheless, it is possible to incorporate long chain branches such as low density polyethylene into the structure. This content is also preferable in the sense that it can be applied to various molding processes, such as being an ethylene-α-olefin copolymer, having a high melt tension and a significant change in melt viscosity with respect to shear rate (high shear and low viscosity).
[0032]
  Moreover, although it is the content reflected in adhesion | attachment of dissimilar materials, the ethylene-alpha olefin copolymer by a single site type catalyst is excellent in the dispersibility of an inorganic compound. In particular, the above density range is still effective. Such strength properties, flexibility, inorganic compound dispersibility, dissimilar material adhesion, moldability
In view of this, it is highly preferable to use this material system.
[0033]
  By using the moisture absorbing film having the material properties as described above, it is possible to obtain a film-like cushioning material having a buffer function having a target function, but the buffer function and the moisture absorption speed are further improved. Then, a foaming agent is blended in one or both of the polyolefin resin composition (A) and the polyolefin resin (B) having a hygroscopic function, and foamed. As such a foaming agent, not only an inorganic foaming agent such as baking soda but also an organic foaming agent such as azodicarboxylic acid amide, dinitrosopentamethylenetetramine, oxybisbenzenesulfonylhydrazide can be used. The addition amount is preferably 0.01 to 2 parts by weight with respect to 100 parts by weight of the polyolefin resin, and the expansion ratio is preferably 1 to 50 times, preferably 10 to 25 times. When it is smaller than 1 time, it is the same as the structure without the foaming agent described above, and the function is not inferior, but the cost is increased only by adding the foaming agent, and there is also an adverse effect on productivity. When it is larger than 50 times, the physical properties as a film are lowered.
[0034]
  If necessary, various additives other than the above, such as antioxidants, flame retardants, slip agents, anti-blocking agents, dispersants, and light stabilizers may be blended.
[0035]
  Although the hygroscopic film as the film-like cushioning material of the present invention is described as being limited to the development of applications for packaging members, of course, the hygroscopic film may be laminated on various substrates. The method of laminating is not particularly limited, and various laminating methods such as dry lamination and extrusion lamination can be adopted. The base material is also like a stretched polypropylene film, a stretched polyethylene film, a stretched polyester film or a stretched polyamide film. The film may be a film in which a polyvinylidene chloride coating agent is provided on these films. A multilayer film with an aluminum foil layer interposed may be used. Furthermore, an aluminum vapor deposition, a silica vapor deposition, an alumina vapor deposition film, or a composite film in which a functional coating layer is further provided on these vapor deposition layers may be used. The laminate thus obtained can also be used as a soft package, and by using the above-described rigidity, flexibility and elastic recovery, it is possible to give a falling bag impact, It is possible to obtain a package capable of maintaining the strength properties even if the hole property is imparted or the basis weight of the packaging material itself is lowered.
[0036]
  The manufacturing method of the polyolefin-type resin composition (A) which mix | blended these inorganic compounds which have a moisture absorption function is described below. Dry blending materials of various predetermined blending amounts set according to the final product molding method and required moisture absorption function using a ribbon mixer, tumbler mixer, Henschel mixer, etc., such as single screw extruder, twin screw extruder, etc. It can be obtained by kneading at a melting point to 280 ° C., preferably 260 ° C. or less, more preferably 240 ° C. or less, using a kneader such as an extruder or Banbury. At that time, if necessary, the inorganic moisture absorbent may be surface-treated with a dispersant such as an olefin wax in advance. The obtained strand is cooled by air cooling, and after pelletizing, it is stored in a packaging form such as an aluminum bag. Thereafter, it is possible to obtain a moisture-absorbing container using the molding method described below.
[0037]
  In FIG. 1, the schematic diagram of the moisture absorption film used in the following examples is shown. This hygroscopic film is used as a film-like cushioning material, and its production method is carried out using a film forming machine such as a coextrusion inflation film forming machine or a coextrusion cast film forming machine, and has the above-mentioned hygroscopic inorganic compound. If necessary, the polyolefin resin composition (A) is diluted with a compatible resin and together with the polyolefin resin (B) provided on both sides, the melting point is not lower than 260 ° C., preferably not higher than 240 ° C. More preferably, the film is formed at 220 ° C. or lower. When using a foaming agent, mixing the masterbatch which mix | blended the foaming agent by this moisture absorption film manufacturing process is mentioned.
[0038]
【Example】
  Examples of the present invention are shown below, but are not limited thereto.
[0039]
[Preparation of polyolefin resin composition (A) containing an inorganic compound having a hygroscopic function: material]
  The following materials were used.
<Polyolefin resin>
  A-1: single-site ethylene-octene-1 copolymer (flexural modulus 110 MPa, density 0.902 g / cm^Three  )
  A-2: Single-site ethylene-hexene-1 copolymer (flexural modulus 80 MPa, density 0.901 g / cm^Three)
  A-3: Homopolypropylene (flexural modulus 1750 MPa, density 0.900 g / cm^Three)
  A-4: Multisite ethylene-octene-1 copolymer (flexural modulus 420 MPa, density 0.925 g / cm^Three)
<Inorganic compound having moisture absorption function>
  B-1: Calcium oxide CaO
  ・ B-2: Alumite K₂Al₆(OH)₁₂(SO_Four)_Four
[0040]
[Preparation of polyolefin resin composition (A) blended with inorganic compound having hygroscopic capacity: production] 67 inorganic compounds having a hygroscopic function with respect to 100 parts by weight of the resin containing the polyolefin resin as an essential component in advance. The mixture adjusted so that it might become a weight part (weight% as 40 wt%) was compounded by discharge 9 kg, 200 degreeC, and 50 rpm with the twin-screw extruder (phi = 30, L / D = 49). This high-concentration dispersion was used as a master batch for the following molding. The obtained master batch was air-cooled pelletized and stored in an aluminum package (replaced with inert gas).
[0041]
[Manufacture of moisture-absorbing film: materials]
  The following were used as the polyolefin resin (B).
<Polyolefin resin>
  C-1: Single-site ethylene-hexene-1 copolymer (density 0.935 g /cm ³ )
  C-2: Single-site ethylene-hexene-1 copolymer (density 0.945 g /cm ^Three )
  C-3: Single-site ethylene-hexene-1 copolymer (density 0.902 g /cm ^Three )
[0042]
[Manufacture of moisture-absorbing film: film formation]
  A three-layer / three-layer coextrusion cast film forming machine was used for forming the hygroscopic film (φ = 65 L / D = 23). The processing temperature is 220 ° C., and the processing speed is 40 m / min. It is. If necessary, an appropriate amount of azodicarboxylic acid amide was added as a foaming agent.
[0043]
[Evaluation method: Hygroscopic capacity evaluation]
  A container made of homopolypropylene having an internal volume of 250 ml and a moisture resistance of 1 mg / container / day was prepared, and a sensor was attached to the container as shown in FIG. The glass container was filled with 50 tablet-shaped drugs (2 g each) (volume: about 150 ml), or 150 g of powdered drug (volume: about 150 ml). Thereafter, a hygroscopic film cut to a size of 200 × 200 mm was filled as a film-like cushioning material. The content of evaluation is a change in the humidity in the container accompanying the opening / closing operation of the container in the storage at 40 ° C.-90% relative humidity. Opening and closing operations are performed once every two days for 5 minutes in a 40 ° C.-90% relative humidity environment, and each time, 5 tablets are taken out and 15 g are extracted from powdered drugs. The operation was performed 10 times (equivalent to 20 days). It is the reached humidity evaluation when it is repeated 50 times.
[0044]
[Evaluation of buffer function]
  A similar container without a sensor was prepared, and a vibration test in the vertical direction of the container was performed. Although the evaluation environment is under 25 ° C.-65% relative humidity, the opening / closing operation and the method of extracting the contents are the same as the moisture absorption evaluation. The observations at this time included destruction of the contents, adhesion of the contents, elastic recovery (the shape of the moisture absorbing film as a cushioning material), handling (ease of removing the moisture absorbing film by repeating the container opening / closing operation, loading) Ease).
[0045]
<Example 1>
  Using A-1, B-1, and C-1, the polyolefin resin layer (A) containing a hygroscopic inorganic compound was 50 μm, and the polyolefin resin (B) on both sides thereof was 15 μm. The function of this moisture absorption film is a drying function. This hygroscopic film was evaluated based on the above evaluation method. The evaluation results are shown in Tables 1 and 2.
[0046]
<Example 2>
  Example 1 is the same as Example 1, except that A-1, B-1, and C-2 were used. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
[0047]
<Example 3>
  The same as Example 1 except that A-2, B-2, and C-1 were used. However, this function is a humidity control function. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
[0048]
<Example 4>
  Example 2 is the same as Example 1 except that A-2, B-2, and C-2 were used. However, this function is a humidity control function. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
[0049]
<Example 5>
  Example 1 is the same as Example 1 except that the polyolefin resin layer (A) containing a hygroscopic inorganic compound is 50 μm and the polyolefin resin (B) on both sides thereof is 25 μm. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
[0050]
<Comparative Example 1>
  Example 1 is the same as Example 1, except that A-1, B-1, and C-3 were used. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
[0051]
<Comparative Example 2>
  Example 3 is the same as Example 3 except that A-2, B-2, and C-3 were used. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
[0052]
<Comparative Example 3>
  Example 4 is the same as Example 1 except that A-4, B-1, and C-1 were used. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
[0053]
<Comparative example 4>
  A-3, B-1, and C-3 were used, but the rigidity was too strong to fill the container. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2. When filling
Cracks were observed in the intermediate layer due to stress.
[0054]
<Comparative Example 5>
  Example 1 is the same as Example 1 except that the polyolefin resin layer (A) containing the hygroscopic inorganic compound is 25 μm and the polyolefin resin (B) on both sides thereof is 25 μm. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2. Although the rigidity is lower than that of Comparative Example 4, it was difficult to remove the moisture-absorbing film from the container at the beginning of evaluation (when the content was large).
[0055]
[Table 1]

[0056]
[Table 2]

[0057]
【The invention's effect】
  According to the present invention, it is possible to efficiently absorb moisture inside the packaging container to maintain a dry state or a humidity-controlled state, and have contradictory physical properties such as flexibility and rigidity, and further, an excellent elastic recovery property. A cushioning material can be provided. The film-like cushioning material of the present invention has not only a drying function and a humidity control function by blending an inorganic compound having hygroscopicity, but also has a cushioning function, and is used as a packaging member as a cushioning film or the like. Used for etc. In addition, the film-like cushioning material of the present invention has no problem of accidental ingestion or accidental eating, unlike conventional sachet-type moisture absorbents and tablet-like moisture absorbents, and unlike these desiccants provided with an adhesive, Wearing is not cumbersome. Furthermore, since the film-like cushioning material of the present invention can be laminated not only on a packaging member but also on various substrates as a cushioning film or the like, it has a wide range of applications such as deployment to a soft packaging agent. The film-like cushioning material of the present invention is excellent in contents protection performance (deterioration due to moisture absorption, damage to contents, etc.) that has been required in recent years.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a film-like cushioning material as one embodiment of the present invention.
FIG. 2 is an explanatory view illustrating an example in which a film-like cushioning material according to an embodiment of the present invention is used as a packaging member having rigidity and flexibility.
  A shows an example in which the buffer function is maintained even when the contents move due to vibration.
  B shows an example in which the contents move due to vibration and the buffer function is lost.
FIG. 3 is an explanatory view illustrating an example in which a film-like cushioning material according to an embodiment of the present invention is used as a packaging member having elastic recovery properties.
  A shows an example in which the buffer material expands and the head space is replenished when the content decreases.
  B shows an example in which the cushioning material maintains its original shape and the headspace cannot be replenished even if the contents are reduced.
FIG. 4 is an explanatory view illustrating an example of an evaluation method for evaluating the hygroscopicity of the film-like buffer material of the present invention.
[Explanation of symbols]
  a: Hygroscopic film
  a-1: Polyolefin resin (A) containing a hygroscopic inorganic compound
  a-2: Polyolefin resin (B)
  a-3: Inorganic compound having hygroscopicity
  a-4: Foamed part
  b: Container
  c: Tablet-like contents
  d: Humidity sensor

Claims (6)

In a film-like cushioning material comprising a multilayer film including a polyolefin resin composition layer (A) containing an inorganic compound having a moisture absorption function, a polyolefin resin layer (B) on both sides of the polyolefin resin composition layer (A) ) is provided, when the density of the polyolefin resin as a base resin of the polyolefin resin composition layer (a) expressed in _{d a,} a _{d a} ≦ _0.930g / cm ^3, and the polyolefin-based resin when the density of the polyolefin-based resin layer (B) expressed in _{d B,} as well as a ^{_{d B ≧ 0.910g / cm 3,}} d a < satisfy the relationship _{d B,} the polyolefin resin composition layer ( A film-like cushioning material, wherein at least one of A) or the polyolefin-based resin layer (B) is foamed. When the thickness of the polyolefin resin layer (A) expressed t _A, the total thickness of the polyolefin resin layer (B) at t _B, according to claim 1, characterized in that to satisfy the relation of t _A ≧ t _B The film-like cushioning material as described.   3. The polyolefin resin composition layer (A) comprises a resin composition containing 1 to 100 parts by weight of an inorganic compound having a hygroscopic function with respect to 100 parts by weight of a polyolefin resin. The film-like cushioning material as described.   The polyolefin resin used as the base resin of the polyolefin resin composition layer (A) or at least one of the polyolefin resins (B) is a cyclopentadienyl derivative periodic table III, IV, V, VI. , An IX, an X-olefin copolymer obtained by using a single-site catalyst composed of methylaluminoxane, if necessary, or a complex composed of a transition metal atom of group IX or X (provided that α-olefin: propylene, butene) -1, hexene-1, octene-1, 4-methylpentene-1, C3-C8, or C9 or higher higher olefin) as an essential component. 2. A film-like cushioning material according to item 1.   The inorganic compound having a hygroscopic function has a hygroscopic ability of at least 10% of its own weight under a relative humidity of 40 ° C.-90%, and the inorganic compound is a sulfate such as zeolite, calcium oxide, calcium chloride, magnesium sulfate. The film-like buffer material according to any one of claims 1 to 4, which is selected from at least one of a compound, alumina, activated carbon, clay mineral, and silica gel.   The foaming agent is mix | blended with at least one of the said polyolefin resin composition layer (A) or the polyolefin resin layer (B), and it was made to foam in the range of 1 to 50 times of expansion ratios, 6. The film-like cushioning material according to any one of 5 above.

Images