JP2013018546A - Easily unselable inflation film for double bag package, and double bag package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double bag package hardly receiving influence of pressure, time, temperature when sealing even when pressedly sealing few times and changing sealing temperature, in which a package can be manually unsealed and a bag is not broken by a shock when filling the same with contents and falling during transportation.SOLUTION: An inflation film for the double bag package of a constitution including an outer layer having easy peelability, an intermediate layer comprising a polyamide resin, and an inner layer comprising a low density polyethylene resin is characterized in that the outer layer having the easy peelability has easy peeling strength of 0.98 to 19.6 N/15 mm width in any of sealing temperatures of 130°C, 140°C, 150°C and the thickness of the outer layer is 3 to 15 μm. The double bag package having the easy peelability is characterized in that the bag is made of the inflation film.

Description

  TECHNICAL FIELD The present invention relates to an inflation film for a double bag package, and a double bag package formed from the film, for example, a saucer, a kneaded paste, a chocolate cream heated to 80 ° C. or more. Related to an inflation film for a double bag package and a double bag package for forming a double package having an easy peel property (easy-opening property) that can be hot-filled with jam, margarine, processed oils and fats, etc. It is.

  Traditionally, as packaging containers for filling liquid foods and viscous foods such as vinegar, sake, soy sauce, sauce, sauce, soup, soup, various beverages, margarine, seasonings, kneads, chocolates, metal cans, glass bottles, etc. A container was used. However, recently, due to environmental problems, it has been required to reduce the volume of packaging containers and to make them easily disposable. In order to meet these requirements, packaging bodies made of plastic films have been used as packaging containers for liquid materials.

  Plastic films are superior to metal cans and glass bottles in that they are lightweight and can reduce distribution costs and disposal costs. As a packaging container filled with a liquid or viscous food, it is an absolute requirement that the contents do not leak during storage or transportation. However, plastic film is thinner and less durable than containers such as metal cans and glass bottles, so pinholes can be generated or broken by vibrations, impacts, and friction during transportation. Has the essential problem of leaking.

  In order to solve such a problem, as a packaging body made of a plastic film, a double bag packaging body in which two films are stacked is generally used (for example, Patent Documents 1 to 5).

  According to such a double-layer double bag package, there is a certain degree of freedom between the two films even when an object to be stored is accommodated therein. Therefore, even if an impact is applied to the double bag package during transportation, the double bag package is supported by contacting the inner side film that supports the object and the pallet or other package. It is possible to prevent the occurrence of pinholes and bag breakage by causing a certain amount of sliding between the outer film and the outer film and absorbing the impact. However, when a laminated film having a stretched film is used as disclosed in Patent Document 1, the film is hard, so that it is difficult to squeeze the contents when the double package is opened, and the contents remain and work suitability deteriorates. There's a problem. In addition, if the contents remain, there is a problem that a rotting odor due to the remaining contents is generated or bacteria are propagated until the contents are discarded.

  Further, as a resin material constituting the inner layer of the double bag package, for example, as disclosed in Patent Document 3, a relatively low density low density polyethylene (hereinafter abbreviated as “LDPE”) may be used. ), It has an excellent aspect that heat sealing is easy at the time of bag making, while directly storing food etc. heated to 80 ° C. or more inside the double bag package. In such a case, blocking between the inner layers occurs, and there is a problem that the bag is easily broken due to vibration, impact, and friction during transportation. In addition, there is a problem that it is difficult to manage the pitch during continuous production because the film is stretched by the heat and weight of the contents to be filled.

  In order to solve the blocking problem, the present inventor used LDPE as a resin material constituting the inner layer of the double bag package as described in Patent Document 5, and the Vicat softening point of this LDPE By setting the density and density within a predetermined range, even when food or the like heated to 80 ° C. or higher is directly stored inside the double bag package, the inner layers are unlikely to block each other and are resistant to pinholes. We proposed an excellent film that does not stretch even when hot filled with foods.

  It is preferable that the package has an easy peel property so that the contents can be easily taken out. However, the film described in Patent Document 5 forms a double bag package by complete sealing, and in order to take out the contents from the package, it is necessary to open the package using a cutter or scissors. is there. For this reason, there is a problem that workability at the site where food is used is poor, and since opening using a cutter or the like, the opened section becomes garbage and the garbage increases, and the section is mixed in the contents. There is also a problem.

  Therefore, in order to solve these problems, the present inventor sets the Vicat softening point and density of two types of resins constituting the easy peel layer within a predetermined range as described in Patent Document 6, so that the user can package the package. Has been developed as a double bag package that can be easily opened by hand and does not break even when the contents are filled or dropped during transportation. However, the size of the double package varies depending on the amount of contents, and when the seal time and temperature are changed, there will be variations in easy peel strength, and the length and feed pitch of the vertical seal bar of the packaging machine will vary. Since they do not coincide with each other, there is a problem that when the same portion of the film is sealed several times, the easy peel strength is locally increased, resulting in poor openability.

JP 2003-305783 A JP 2003-335302 A JP 2003-26234 A JP 2002-234547 A JP 2007-15725 A JP 2009-029434 A

  The present invention has been made in view of the above circumstances, and the problem to be solved is that the seal temperature range is wide, the easy peel strength is stable even after several press seals, and the effects of seal time, seal temperature, and seal pressure are affected. It is to provide a film that is difficult to receive.

  As a result of intensive studies in view of the above problems, the present inventor has found that the above problems can be easily solved by a film having a specific configuration, and has completed the present invention.

  That is, the gist of the present invention is an inflation film for a double bag package comprising an outer layer having an easy peel property, an intermediate layer made of a polyamide resin, and an inner layer made of a low-density polyethylene resin. The outer layer has an easy peel strength of 0.98 to 19.6 N / 15 mm width at any of sealing temperatures of 130 ° C., 140 ° C. and 150 ° C., and the thickness of the outer layer is 3 to 15 μm. The present invention resides in an inflation film for a double bag package, and a double bag package having an easy peel property, wherein the bag is made from the inflation film.

  According to the present invention, it is possible to provide a film having a wide seal temperature range, stable easy peel strength even after several press seals, and less susceptible to seal time, seal temperature, and seal pressure. Target value is high.

  The inflation film of the present invention includes an outer layer having an easy peel property having a predetermined layer thickness and a predetermined cohesive force. Thereby, a good easy peel property can be imparted to the double package manufactured using the inflation film of the present invention. The package must have a sealing property to prevent leakage of the contents. Moreover, in this invention, the easy peel property is provided for workability | operativity improvement in use of a package body further. In the present invention, the outer layer having an easy peel property having a predetermined layer thickness and a predetermined cohesive force balances the sealing property and the easy peel property in the double bag package. The easy peel property in the present invention is due to cohesive failure, and when the double package is opened, the easy peel layer itself is broken and peeled off, and the easy peel layer remains on both sides of the peeled surface. It is. The inflation film of the present invention is provided with pinhole resistance by including an intermediate layer made of a polyamide resin. Moreover, by providing the inner layer which consists of a low density polyethylene resin, the heat seal property at the time of package body preparation becomes favorable.

In the present invention, the outer layer having an easy peel property (hereinafter sometimes referred to as “easy peel layer”) is 50 to 90% by mass of the resin composition A shown below, with the total mass of the outer layer being 100% by mass. It is preferable that 10-50 mass% of resin composition B is provided.
Resin composition A: linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, the main component of which is a melt flow rate of 6 g / 10 min or more Resin composition / resin composition which is at least one selected from the group consisting of a polymer, an ethylene-methacrylic acid copolymer, an ethylene-methyl methacrylate copolymer, an ethylene-methyl acrylate copolymer, and an ionomer thereof Product B: Resin composition whose main component is polybutylene or polypropylene having a melt flow rate of 2 g / 10 min or less The “main component” in Resin Composition A and Resin Composition B is based on the mass of the entire resin composition (100% by mass), each of the resins listed above is preferably 70% by mass or more, more preferably 80% by mass. In addition to the resins listed above, various additives and general-purpose resin components are allowed to be mixed, unless the effects to be provided by the outer layer are impaired.

  In the present invention, by using an easy peel layer containing the resin composition A and the resin composition B at such a predetermined ratio, it becomes easy to adjust the cohesive force of the easy peel layer to the above range, and easy peel properties Can be made good. In addition, conventionally, the cut length may be different when making a double package, and a sealer may need to be pressed multiple times in the sealing process, where it is pressed multiple times and where it is pressed only once However, by using the above-described easy peel layer, a good openability can be obtained with a stable easy peel strength even when a plurality of presses with a sealer are applied.

  Moreover, it is preferable to use resin of the viscosity range shown above for the resin compositions A and B from the point that the stable easy peel strength is obtained even if it changes seal time, seal temperature, and seal pressure.

  As the resin composition A, it is preferable to use a linear low density polyethylene (hereinafter sometimes referred to as “LLDPE”) having a melt flow rate of 6 g / 10 min or more. By using a low viscosity type having a melt flow rate of 6 g / 10 min or more, fluffing of the cohesive failure layer can be prevented, and a beautiful release surface can be obtained. Further, the difference in the easy peel strength between the vertical direction and the horizontal direction can be reduced.

  The resin composition B preferably uses polybutylene (hereinafter “PB”) or polypropylene (hereinafter “PP”) having a melt flow rate of 2 g / 10 min or less. By using a type having a melt flow rate of 2 g / 10 min or less and a high viscosity, the dispersed particle diameter of the cohesive failure layer with respect to the resin composition A is increased, and a beautiful release surface can be obtained.

  In the present invention, the range of the thickness of the intermediate layer is usually 5 to 30 μm. By setting the thickness of the intermediate layer in such a range, it is possible to impart good pinhole resistance to the double bag package to be formed and also to impart good squeeze properties (easiness to squeeze out the contained material). .

  In the present invention, the outer layer preferably contains a slip agent and / or an antiblocking agent. Thereby, generation | occurrence | production of the bump and the sagging of a winding film can be reduced. In addition, it can reduce friction with the roll on the packaging machine and friction at the former part (sailor part) that is folded into a cylindrical shape, and reduce wrinkling during bag making that causes meandering and seal leakage during film feeding. Can do.

Moreover, it is preferable that the low density polyethylene resin of an inner layer is a linear low density polyethylene resin (LLDPE). LLDPE is characterized by strong physical properties such as tensile strength, elongation, pinhole strength, and rigidity.

  In the present invention, at least one adhesive resin layer may be provided between the intermediate layer and the outer layer and / or the inner layer. Thereby, the adhesive strength between each layer can be raised more.

  In the present invention, at least one ethylene-vinyl acetate copolymer saponified resin layer (hereinafter sometimes abbreviated as “EVOH layer”) is provided between the intermediate layer and the outer layer and / or inner layer. It may be. Thereby, a gas (oxygen) barrier property can be imparted to the inflation film.

  In the inflation film for a double bag package of the present invention, first, three or more kinds of resins are heated and melted to a predetermined temperature by an extruder, and the pressure is increased. Then, air is blown into the inside of the cylindrical mold, and a tubular film composed of an outer layer, an intermediate layer, and an inner layer is discharged from the gap between the molds. The tube-shaped film is folded into a flat film by folding means composed of a roll or the like, and then wound into a roll by a winder. In this way, the inflation film of the present invention is manufactured. The film wound up on the roll becomes an original fabric for producing a double bag package.

  The inflation film for double bag packaging according to the present invention comprises an outer layer having an easy peel property, an intermediate layer made of polyamide resin, and an inner layer made of low-density polyethylene resin.

In the present invention, the inner layer is made of LDPE, and can be bonded by heat sealing when a double bag package is manufactured. Further, the LDPE constituting the inner layer preferably has a predetermined Vicat softening point and density. The lower limit of the Vicat softening point of LDPE is 110 ° C. or higher, preferably 115 ° C. or higher, more preferably 120 ° C. or higher, and the upper limit is 125 ° C. or lower, preferably 124 ° C. or lower. The density, the lower limit is usually 0.930 g / cm ^3, preferably 0.935 g / cm ³ or more, still more preferably 0.937 g / cm ³ or more, the upper limit is usually 0.940 g / cm ³ is there.

  By using such LDPE, it is possible to prevent the inner layer blocking of the tube film during hot filling while ensuring good heat sealability. For example, when an 80 to 100 degreeC to-be-contained object is hot-filled in the state which formed the double bag, it can prevent that this inner layer blocks. Here, the blocking in the present invention means that the inner layers are fused. If the inner layers are fused to each other, the degree of freedom of the two films, which is an advantage of the double bag, is hindered, the impact cannot be absorbed, and pinholes and bag breakage occur.

In the case of LDPE having a Vicat softening point of 110 ° C. or higher, as the Vicat softening point increases, the density gradually increases. For example, in the case of LDPE having a Vicat softening point of 120 ° C. or higher, the density is close to 0.940 g / cm ^3. It is difficult to block each other, and the elongation of the film due to heat can be minimized.

  The LDPE constituting the inner layer is preferably LLDPE, and the LLDPE is preferably a copolymer of ethylene and hexene-1 having 6 carbon atoms or octene-1 having 8 carbon atoms. LLDPE has higher physical properties such as tensile strength, elongation, anti-pinhole strength and rigidity than LDPE. Further, as the number of carbon atoms of the copolymer increases as described above, the physical property strength increases in proportion.

  The lower limit of the thickness of the inner layer is usually 10 μm, preferably 15 μm or more, more preferably 20 μm or more, and the upper limit is usually 50 μm, preferably 40 μm or less, more preferably 35 μm or less. By setting the thickness of the inner layer to 10 μm or more, pinhole resistance and heat resistance can be maintained. On the other hand, when the thickness of the inner layer is 50 μm or less, an appropriate squeeze property is imparted to the double bag package formed from the film, and the work of squeezing out the contents becomes good.

  In the present invention, the intermediate layer is made of a polyamide resin. The type of polyamide resin is not particularly limited, but from the viewpoint of pinhole resistance, examples of the polyamide-based synthetic fiber-based resin include 6 nylon, 66 nylon, 69 nylon, 6-66 nylon, 12 nylon, 11 nylon, and 610. It is preferable to use a polymer such as nylon, 612 nylon, 6I-6T nylon, MXD6 nylon or the like, a copolymer containing two or more of these as polymerized units, and a mixture of these polymers. Among these, it is particularly preferable to use 6 nylon or 6-66 nylon because it is excellent in extrusion moldability and film forming stability in the inflation method, is inexpensive and can be stably obtained, and the like.

  The lower limit of the thickness of the intermediate layer is usually 5 μm, preferably 7 μm or more, more preferably 10 μm or more, and the upper limit is usually 30 μm, preferably 25 μm or less, more preferably 20 μm or less. By setting the lower limit of the thickness of the intermediate layer formed of the polyamide resin to 5 μm, good pinhole resistance can be obtained and the film is difficult to stretch. Moreover, moderate squeeze property can be provided to the double bag packaging body formed with the film by making an upper limit into 30 micrometers.

  In the present invention, the outer layer is a layer having an easy peel property having a predetermined cohesive force and a layer thickness.

  The easy peel strength (cohesive force) of the outer layer needs to be 5.88 to 11.8 N / 15 mm width. If the cohesive force is less than 5.88 N / 15 mm, the contents are broken at the time of filling, and the seal is lost due to an impact during transportation or the like. On the other hand, if it exceeds 11.8 N / 15 mm, the openability of the hand actually deteriorates, and stretching of the film, fluffing of the peeled surface and film residue occur.

  The cohesive force is measured by heat-sealing the outermost layers of the composite film (sealing temperatures: 130 ° C., 140 ° C., and 150 ° C.) and peeling the heat-sealed portion by 180 ° at a tensile rate of 200 mm / min. This was done by measuring the peel strength at the time.

  The resin constituting the easy peel layer preferably comprises 50 to 90% by mass of resin composition A and 10 to 50% by mass of resin composition B, with the mass of the entire outer layer being 100% by mass. The melt flow rate of the resin composition A is preferably 6 g / 10 min or more, and the melt flow rate of the resin composition B is preferably 2 g / 10 min or less. For example, a resin composition A and a resin composition B described below can be mixed at a predetermined ratio.

  As the resin composition A, the main component is a linear low density polyethylene (LLDPE), a melting point ethylene-vinyl acetate copolymer (EVA), an ethylene-acrylic acid copolymer having a melt flow rate of 6 g / 10 min or more. Copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA) having a melting point of 100 ° C. or less, ethylene-methyl methacrylate copolymer (EMMA), ethylene-methyl acrylate At least one resin composition selected from the group consisting of a copolymer (EMA) and these ionomers can be used. Among these, linear low density polyethylene (LLDPE) can be suitably used from the viewpoint of hot tack.

  As the resin composition B, a resin composition whose main component is polypropylene polybutylene (PB) or (PP) having a melt flow rate of 2 g / 10 min or less can be used. As the PP constituting the main component of the resin composition B, any of random copolymers, homopolymers, block copolymers and the like can be used, and among these, random copolymers can be suitably used. Examples of the copolymer component of the copolymer include α-olefins other than propylene such as ethylene.

  The lower limit of the thickness of the outer layer is 3 μm, preferably 5 μm or more, and the upper limit is 15 μm, preferably 10 μm or less, more preferably 8 μm or less. When the thickness of the outer layer is too thin, there is a problem that the stability of the easy peel is inferior and it is difficult to form a film. Further, if the outer layer is too thick, there is a problem that it is difficult to open due to fluffing at the time of opening or film residue.

  In the package formed using the inflation film of the present invention, both the vertical seal portion and the horizontal seal portion have all easy peel properties. Therefore, only the seal portion may be opened to take out the contents, or the vertical seal portion may be opened together with the seal portion to enlarge the opening. Furthermore, all the sealing portions may be opened.

  The double bag package of the present invention is often used as a commercial package mainly containing a large amount of contents. For example, in the case of a package containing business-use chocolate cream, first, the upper seal portion is opened, and most of the chocolate cream is taken out from the tray. Thereafter, the package is squeezed to take out the remaining contents as much as possible. However, since the package is large, a certain amount of contents still remains in the package. If the remaining chocolate cream is discarded without being used, the chocolate cream is not only wasted, but there is also a problem of separating garbage from raw garbage, and if it is not separated, the chocolate cream will rot. Hygiene problems such as odor and bacteria are generated.

  In the double bag package of the present invention, as described above, the entire package can be opened and returned to the original sheet shape. Therefore, the remaining chocolate cream can be wiped clean with a spatula or the like. As described above, in the double bag package of the present invention, not only can the contents be effectively utilized to the maximum, but also the problem of waste separation and hygiene can be solved.

  In addition, when the cohesive fracture easy peel layer of the present invention is opened, a seal mark remains on the seal portion. The seal mark serves as proof that the product has been securely sealed, and has the effect of giving a sense of security to the user of the contents.

  A slip agent can be added to the inner layer and / or the outer layer for the purpose of imparting slipperiness. The slip agent is not particularly limited as long as it can impart slipperiness, and examples thereof include hydrocarbon-based lubricants, fatty acid-based higher alcohol-based lubricants, amide-based lubricants, ester-based lubricants, and metal soap-based lubricants.

  Typical amide-based lubricants for polyethylene slip agents include stearic acid amide, oleic acid amide, and erucic acid amide. The addition amount of the amide-based lubricant is generally in the range of 0.1 to 0.5 parts by mass with respect to 100 parts by mass of the resin constituting each layer, and this addition amount improves and prevents blocking between the inner layers. Can do. Examples of the metal soap-based lubricant include lead stearate, zinc stearate, calcium stearate, magnesium stearate and the like. The addition amount of the metal soap lubricant is 0.1 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and 10 parts by mass with respect to 100 parts by mass of the resin constituting each layer. Part or less, preferably 5 parts by weight or less, more preferably 3 parts by weight or less.

  An antiblocking agent can be added to the inner layer and / or the outer layer for the purpose of imparting antiblocking properties. The anti-blocking agent is not particularly limited as long as it can impart anti-blocking properties, but examples of inorganic agents include talc and zeolite. Talc is a white powder rich in lubricity and oily, and its surface is lipophilic and hydrophobic. Zeolite is a hydrous aluminosilicate of alkali and alkaline earth metals and can prevent stickiness. The anti-blocking agent is considered to exhibit a function of preventing blocking by forming fine irregularities on the surface of the resin layer and suppressing adhesion between two adjacent layers. The addition amount of the anti-blocking agent is 0.1 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and 10 parts by mass or less, relative to 100 parts by mass of the resin constituting each layer. Preferably it is 5 mass parts or less, More preferably, it is 3 mass parts or less.

  Addition of the above slip agent and anti-blocking agent prevents the inner layers from blocking each other in the inflation film, and can improve the slip between the outer layer and the packaging machine in the production process of the double bag package.

  Further, at least one adhesive resin layer can be provided between the intermediate layer and the outer layer and / or the inner layer. The adhesive resin used in the adhesive resin layer is not particularly limited as long as the outer layer, the intermediate layer, and the inner layer can be bonded to a required strength, but a polyolefin resin modified with an unsaturated carboxylic acid or a derivative thereof is preferably used. Can be used. Examples of the unsaturated carboxylic acid and derivatives thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid and derivatives thereof. Examples of unsaturated carboxylic acid derivatives include esters and anhydrides of unsaturated carboxylic acids, such as methyl acrylate, methyl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, butyl methacrylate, Examples include vinyl acetate, glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, and sodium acrylate.

  As a commercially available adhesive resin, the Mitsui Chemicals make and brand name Admer are mentioned, for example, It can use suitably in this invention.

  The lower limit of the thickness of the adhesive resin layer is usually 5 μm, preferably 10 μm or more, and the upper limit is usually 20 μm, preferably 15 μm or less. If the thickness of the adhesive resin layer is too thin, sufficient interlayer adhesion cannot be obtained. On the other hand, when the thickness of the adhesive resin layer is too thick, the raw material cost is increased and the transparency is deteriorated.

  Between the intermediate layer and the outer layer and / or the inner layer, at least one EVOH layer can be provided for the purpose of providing an oxygen barrier property. The ethylene content of EVOH used in the EVOH layer is not particularly limited, but from the viewpoint of film formation stability, the lower limit is preferably 32 mol%, more preferably 38 mol% or more, and the upper limit is Preferably it is 47 mol%, More preferably, it is 44 mol% or less. The saponification degree of EVOH is preferably 90 mol% or more, more preferably 95 mol% or more. By maintaining the ethylene content of EVOH and the saponification degree within the above ranges, the coextrudability of the film of the present invention and the strength of the film can be improved.

  When the EVOH layer is provided, the lower limit of the thickness of the EVOH layer is preferably 5 μm, more preferably 8 μm or more, further preferably 10 μm or more, and the upper limit is preferably 30 μm or less, more preferably 25 μm or less, Preferably it is 20 micrometers or less. A sufficient oxygen barrier property can be obtained by setting the lower limit of the thickness of the EVOH layer to 5 μm. Further, by setting the upper limit to 30 μm, the coextrudability of the film is not deteriorated and good film strength can be maintained.

  If the layer structure of the inflation film of the present invention comprises an outer layer having easy peel properties as the outermost layer, an inner layer made of low-density polyethylene resin as the innermost layer, and an intermediate layer made of polyamide resin between them, The layer structure of these layers is not particularly limited.

For example, when expressed by the outer layer (A), the intermediate layer (B), the EVOH layer (C), the inner layer (D), and the adhesive resin layer (E) having easy peel properties, for example, the following layer structure is formed. be able to.
(1) A / E / B / E / D
(2) A / E / C / B / E / D
(3) A / E / B / C / E / D
In the present invention, an additive can be contained in any or all of the outermost layer, the intermediate layer, and the innermost layer as long as the effects of the present invention are not impaired. For example, when a pigment is added, there is a merit that it is easy to find out even if the freshness of the object to be accommodated due to the light shielding effect or a film piece is mixed into the object to be accommodated. In addition, the use of pigments having different colors also has the effect of allowing the type of the filling material to be identified by the color of the package. The pigment is preferably added to the outer layer side or the intermediate layer which does not come into contact with the contents.

<Preparation of sample film for evaluation>
As Examples 1-5 and Comparative Examples 1-9, coextruded blown films consisting of 5 layers were produced. The total thickness of the film is 60 μm.

Example 1:
The layer structure of the inflation film is shown below. The inner layer is a layer on the axial center side of the cylindrical film, and the outer layer is a layer on the opposite side.
First layer (outer layer (easy peel layer)): linear low density polyethylene resin (LLDPE) + polybutylene-1 resin (PB-1) (6 μm)
Second layer (adhesive resin layer): carboxylic acid-modified ethylene-vinyl acetate copolymer (7.5 μm)
Third layer (intermediate layer): 6 nylon (11 μm)
Fourth layer (adhesive resin layer): carboxylic acid-modified ethylene-vinyl acetate copolymer (7.5 μm)
Fifth layer (inner layer): linear low density polyethylene resin (LLDPE) (28 μm)
Total thickness 60μm
In the outer layer, 80 mass% of LLDPE (manufactured by Prime Polymer Co., Ltd., Moretec) having a melt flow rate of 8 g / 10 min, and 20 mass of polybutylene-1 resin (manufactured by Mitsui Chemicals, Tuffmer) having a melt flow rate of 1.8 g / 10 min. A composition obtained by adding 100 parts by mass of the entire blend resin and 0.3 parts by mass of an amide-based lubricant as a slip agent was used.

  As the adhesive resin constituting the adhesive resin layer, a carboxylic acid-modified ethylene-vinyl acetate copolymer (manufactured by Mitsui Chemicals, Admer) was used.

  As the polyamide resin constituting the intermediate layer, 6 nylon (Mitsubishi Engineering Plastics, Novamid 6Ny) was used.

For the inner layer, LLDPE having a density of 0.935 g / cm ³ and a Vicat softening point of 120 ° C. (manufactured by Prime Polymer Co., Ltd., Moatech) is 100 parts by mass of the entire LLDPE, and an amide lubricant is used as a slip agent. The composition which added 1.8 mass parts of inorganic antiblocking agents as a mass part and an antiblocking agent was used.

Example 2:
As an outer layer, 80% by mass of LLDPE (manufactured by Prime Polymer Co., Ltd., Ultzex) with a melt flow rate of 6 g / 10 min, and 20 mass of polybutylene-1 resin (manufactured by Mitsui Chemicals, Tuffmer) with a melt flow rate of 1.8 g / 10 min. A blown film was produced in the same manner as in Example 1 except that a composition in which the same slip agent as in Example 1 was added to% blend resin was used.

Example 3:
As an outer layer, 80% by mass of LLDPE (manufactured by Prime Polymer Co., Ltd., Moretec) having a melt flow rate of 8 g / 10 min and 20% by mass of polypropylene resin (Nippon Polypro Co., Ltd., Novatec PP) having a melt flow rate of 1.3 g / 10 min. An inflation film was produced in the same manner as in Example 1 except that a composition in which the same slip agent and antiblocking agent as in Example 1 were added to the blend resin was used.

Comparative Example 1:
As outer layers, 80% by mass of LLDPE (manufactured by Nippon Polyethylene, Novatec PE) with a melt flow rate of 2.5 g / 10 min, and polybutylene-1 resin (manufactured by Mitsui Chemicals, Tuffmer) 20 with a melt flow rate of 1.8 g / 10 min An inflation film is produced in the same manner as in Example 1 except that the composition of the blend resin is 100% by mass and the same slip agent and anti-blocking agent as in Example 1 are added. did.

Comparative Example 2:
As an outer layer, a blend resin of 80% by mass of LLDPE (manufactured by Prime Polymer Co., Moretech) with a melt flow rate of 8 g / 10 min and 20% by mass of a polypropylene resin (manufactured by Prime Polymer Co., Prime Polypro) with a melt flow rate of 7 g / 10 min. In addition, an inflation film was produced in the same manner as in Example 1 except that the total amount of the blend resin was 100 parts by mass, and the same slip agent and anti-blocking agent as in Example 1 were used.

<Evaluation method>
Each sample film for evaluation produced in the above Examples and Comparative Examples was evaluated by the following test.

(1) Peel strength (cohesive strength)
Using each inflation film, a vertical pillow packaging machine ONP-5750 (manufactured by Orihiro) was used to produce a double bag packaging. The seal temperature was made into three types, 130 degreeC, 140 degreeC, and 150 degreeC. The longitudinal seal portion was cut into a strip with a width of 15 mm, and the stress when pulled at a tensile rate of 200 mm / min with a tensile tester was measured. From the measured easy peel strength, 600 to 1200 gf / 15 mm width: “◯” 600 gf / 15 mm width or less or 1200 gf / 15 mm width or more “x”.

(2) Openability The vertical / horizontal seal portions of the double bag package to be sealed a plurality of times at a seal temperature of 140 ° C. were manually opened, and the ease of opening was evaluated. Those that were easily opened were marked with “◯”, those that were difficult to open were marked with “X”, and those that were easily opened and portions that were difficult to open were mixed with “△”.

(3) Drop-off resistance A double bag package filled with water at a seal temperature of 140 ° C. was dropped 10 times horizontally from a height of 80 cm. The case where a bag breakage or seal leakage occurred was indicated as “X”, and the case where no bag breakage or seal leakage occurred was indicated as “◯”.

  In Examples 1 to 3, even when the sealing temperature was changed, the easy peel strength was stable at 8.04 N / 15 mm width to 10.59 N / 15 mm width even when the press sealing was performed twice, and the openability was good. . On the other hand, in Comparative Example 1, since the main agent is LLDPE having a melt flow rate of 2.5 g / 10 min, the easy peel strength varies from 1.27 N / 15 mm width to 10.59 N / 15 mm width depending on the seal temperature and the number of seals. It was not stable, and a seal dropout occurred at a weak easy peel strength, resulting in poor bag drop resistance. Further, fluffing of the peeled surface occurred, and the openability was poor. Also, in Comparative Example 2, since the secondary agent is PP having a melt flow rate of 7 g / 10 min, as in Comparative Example 1, variation in easy peel strength is conspicuous depending on the sealing temperature and the number of seals, and the unsealing properties and drop-off resistance It was inferior in terms of sex.

  The film of the present invention can be suitably used, for example, as a film for a double bag package.

Claims (3)

An inflation film for a double bag package comprising an outer layer having an easy peel property, an intermediate layer made of a polyamide resin, and an inner layer made of a low density polyethylene resin, and the outer layer having the easy peel property has a seal temperature of 130 A double bag package characterized by having an easy peel strength of 0.98 to 19.6 N / 15 mm width at any of C, 140 C and 150 C, and a thickness of the outer layer of 3 to 15 [mu] m. For inflation film. The inflation film for a double bag package according to claim 1, wherein the outer layer having easy peel properties contains 50 to 90% by mass of the following resin composition A and 10 to 50% by mass of the following resin composition B.
Resin composition A: linear low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene having a melt flow rate of 6 g / 10 min or more -Resin composition mainly comprising at least one selected from the group consisting of methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-methyl acrylate copolymer, and these ionomers Resin Composition B : A resin composition containing polybutylene or polypropylene as a main component and having a melt flow rate of 2 g / 10 min or less. A double bag package having an easy peel property, wherein the bag is made from the blown film according to claim 1 or 2.