JP2005047582A - Partition wall material used in pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a partition wall material in a pack capable of effectively separating stored contents such as food or the like and gas absorbing agent and further capable of effectively preventing liquid contained in the stored contents from transferring to the absorbing agent side. <P>SOLUTION: This partition wall material is constituted such that the stored contents such as food or the like and gas absorbing agent are separated from each other in the pack where the stored contents and the gas absorbing agent are stored. The partition wall material includes a resin layer made of polylactic acid type polymer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a partition wall material used in a package, and in particular, in a package containing contents such as food and a gas absorbent, used in the package for separating the contents and the gas absorbent. It is related with the partition material.

  When a package is made by packaging food containing moisture with a sealing bag made of a resin film, etc., the oxygen present in the package comes into contact with the food, which causes aerobic bacteria such as mold to be generated. It is known to rot. In addition, in foods that have not been completely sterilized, it is known that carbon dioxide gas is generated by fermentation with yeast or the like, thereby reducing the freshness of the food. Furthermore, it is known that fruits and vegetables such as vegetables and fruits among foods generate a plant hormone, ethylene gas, and cause a decrease in freshness due to self-sensitization.

  Therefore, in a package containing various foods, a gas absorbent is stored together with various foods to absorb oxygen, carbon dioxide gas, ethylene gas, water vapor, etc., and prevent the content of various foods from being spoiled and reduced in freshness. It is known to do. In general, these gas absorbents are often in a powder form, and when stored in a package as they are, they are mixed into foods and the like. For this reason, the gas absorbent is stored in the package in a state separated from various foods. That is, (1) a method of storing together with various foods in a package in a state separated from various foods by some partition material, (2) a gas absorbent between the partition material and a base sheet such as an aluminum foil A method of storing the sandwiched sheet-like material together with various foods in a package, (3) A method of dividing the package into two chambers with a partition material, storing various foods in one, and storing a gas absorbent in the other Etc. are adopted.

As the partition material, oxygen gas and water vapor present in the package, carbon dioxide gas generated from food, ethylene gas, etc. are allowed to permeate and be absorbed by the gas absorbent. Things are used. For example, a film obtained by laminating paper or non-woven fabric for the purpose of reinforcing the film on a perforated film that can sufficiently impart gas permeability by a perforated part is used (Patent Document 1). However, since the gas absorbent is in a powder form, the gas absorbent may be transferred to the contents such as food through the perforation of the perforated film. In addition, in foods containing liquids such as water and alcohol, there is a problem that this liquid moves to the gas absorbent side through perforation and reduces the gas absorption capacity, so that it cannot serve as a partition material. is there.
Japanese Patent No. 3011928

  The present invention solves the above-mentioned problems, can effectively separate the contents of food and the like and the gas absorbent, and can effectively prevent the liquid contained in the contents from moving to the absorbent material side. It is an object to provide a partition material.

  The present inventor has found that when a specific polymer is used, it can be used as a partition material without opening a hole, and therefore, it is possible to prevent the liquid contained in the content from moving to the gas absorbent side. The invention has been reached.

  That is, the present invention is a partition material for separating the contents and the gas absorbent in a packaging body in which the contents such as food and the gas absorbent are stored, and is a resin made of a polylactic acid polymer The gist of the partition wall material used in a package comprising a layer.

According to the present invention, in the above, it is preferable to include a laminate in which a resin layer made of a polylactic acid polymer and a fiber layer are laminated.
According to the present invention, in the above, the water vapor permeability is preferably 100 to 500 g / (m ² · 24 hours) under the conditions of 40 ° C. and 90% RH.

  According to the invention, in the above, the fiber layer is a nonwoven fabric composed of core-sheath composite fibers, and the melting point of the polymer constituting the sheath is lower than the melting point of the polylactic acid-based polymer constituting the resin layer. It is preferable that

  The gist of the present invention is a gas absorbent filler characterized in that the partition wall material is formed into a bag shape and filled with a gas absorbent.

  According to the present invention, the partition wall material for separating the contents and the gas absorbent in the package containing the contents such as food and the gas absorbent has a resin layer made of a polylactic acid polymer. Since it contains, it can isolate | separate foodstuff etc. and a gas absorbent effectively, and can prevent effectively that the liquid contained in the content transfers to the gas absorbent side.

  The partition material in the present invention is used in a package that stores contents such as food. Examples of the contents include water-containing or wet water, such as vegetables and fruits. Moreover, the thing which contains oil or is wet with oil, for example, fried food etc., is mentioned. Moreover, the thing containing alcohol, the thing wet with alcohol, for example, a fruit cake etc., is mentioned.

  A conventionally known gas absorbent may be used as the gas absorbent that is separated from the contents such as food by the partition material in the package. For example, when it is desired to absorb oxygen in the package, a conventionally known oxygen scavenger is used, and when it is desired to absorb water vapor, a water vapor absorbent such as silica gel is used.

  The partition material in the present invention is for separating contents such as food and gas absorbent, and there are various types of separation modes such as a bag structure. It is comprised by the resin layer which consists of a polymer. The polylactic acid-based polymer has an appropriate gas permeability when formed into a layer, that is, a film. Moreover, since it is in the form of a film, it has a function of not allowing liquid to permeate.

  Examples of the polylactic acid polymer include poly D-lactic acid, poly L-lactic acid, a copolymer of D-lactic acid and L-lactic acid, a copolymer of D-lactic acid and hydroxycarboxylic acid, and L-lactic acid. Any polymer or blend selected from a copolymer of hydroxycarboxylic acid and a copolymer of D-lactic acid, L-lactic acid and hydroxycarboxylic acid may be mentioned.

  Moreover, you may use the blend body of the said polylactic acid-type polymer and biodegradable aliphatic-aromatic copolymer polyester. When such a blend is used, effects such as imparting flexibility and impact resistance to polylactic acid having properties of being hard and brittle at room temperature can be obtained. As the biodegradable aliphatic-aromatic copolymer polyester, those obtained by condensation polymerization of an aliphatic diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid can be used. Examples of the aliphatic diol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Examples of the aromatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanoic acid and the like. By selecting and polycondensing one or more of these, the desired biodegradable aliphatic-aromatic copolymer polyester can be obtained.

  A small amount of another polymer may be blended with the polylactic acid polymer as long as gas permeability is not impaired. In addition, various additives such as a matting agent, a pigment, a crystal nucleating agent, an inorganic filler, and a plasticizer are added to the polylactic acid-based polymer as necessary, as long as the effects of the present invention are not impaired. May be.

  The resin layer can be obtained by a known inflation film forming method or stretching method. Moreover, when laminating | stacking with the fiber layer mentioned later, it can also obtain by forming a resin layer by the extrusion lamination method.

The partition material of the present invention is preferably a laminate in which a resin layer made of a polylactic acid polymer and a fiber layer are laminated. The fiber layer functions to reinforce the resin layer.
As the fiber layer, paper, non-woven fabric, woven or knitted fabric, walif or the like is used. The paper is Western paper, Japanese paper or the like made of natural pulp or synthetic pulp. The nonwoven fabric and the woven / knitted fabric are made of natural fibers or synthetic fibers. The walliff is composed of a split yarn made of synthetic resin. Since the fiber layer has voids between the fibers, it has sufficient gas permeability. A plurality of these fiber layers may be selected and used in combination. For example, a wallet or a nonwoven fabric may be laminated on a laminate of paper and a resin layer, or a nonwoven fabric having a different fiber configuration may be laminated on a laminate of a nonwoven fabric and a resin layer. .

  In the present invention, it is preferable to employ a nonwoven fabric as the fiber layer. Since the nonwoven fabric is not composed of pulp fibers such as paper, the pulp powder does not scatter, is easy to handle, and is superior in cost compared to the woven or knitted fabric. In addition, it is superior in mechanical strength to Warif.

  The fibers constituting the nonwoven fabric are preferably synthetic fibers from the viewpoint of mechanical strength, and polyester fibers and polyolefin fibers can be used. In particular, polylactic acid fibers can also be used in the same manner as the resin layer. The fiber form may be a short fiber or a long fiber. Moreover, it is preferable to use what consists of a core-sheath composite fiber which arrange | positions a high melting-point polymer in a core part, and arrange | positions a low melting-point polymer in a sheath part.

  For example, two sheet-like partition walls made by laminating such a fiber layer and a resin layer made of a polylactic acid-based polymer are overlapped with each other, and the end portions are heated in a pressurized state, whereby the sheath portion If only the low melting point polymer is melted to form a joint, a bag can be formed from the partition material. In such a case, the sheath part melts for heat sealing, but the core part maintains the fiber form, so the tear strength and tensile strength of the joint part can be maintained, and the strength is excellent. Can get a bag. At this time, in order to form a bag without causing thermal damage to the resin layer, the melting point of the polymer constituting the sheath is preferably lower than the melting point of the polylactic acid polymer constituting the resin layer. The polymer constituting the sheath is preferably compatible with the polylactic acid polymer constituting the resin layer.

  As a method for laminating and integrating a resin layer and a fiber layer made of a polylactic acid-based polymer, any method may be used as long as it is laminated so as not to impede gas permeability of the resin layer. For example, a polylactic acid-based polymer is used. The resin layer and the fiber layer may be overlapped and partially melted and thermally bonded. This can be easily obtained by passing a superposition of both layers through a hot embossing device. In addition, a so-called dry laminating method is used in which an adhesive is arranged in a lattice shape between the resin layer and the fiber layer, or is arranged in a random linear or dot shape in the vertical and horizontal directions to bond them together. You may apply. In this case, an appropriate coating method such as a spray method or a transfer method using a gravure roll is selected. Moreover, you may adhere | attach by powder processing methods, such as the method of adhering both, after shaking off the adhesive powder consisting of a synthetic resin to a resin layer or a fiber layer. Alternatively, a heat bonding sheet may be inserted between the resin layer and the fiber layer and melted by heat to bond both layers together. Alternatively, the molten polylactic acid-based polymer may be extruded and laminated on the fiber layer to be integrally laminated. Further, a resin layer (film) made of a polylactic acid polymer and other fiber layers may be integrally laminated through a resin layer made of a polylactic acid polymer laminated on the fiber layer.

The partition wall material of the present invention preferably has a water vapor permeability (40 ° C., 90% RH) described in JIS Z 0208 of 100 to 500 g / (m ² · 24 hours). When it is lower than 100 g / (m ² · 24 hours), it becomes difficult for water vapor and various gases to permeate. On the other hand, if it exceeds 500 g / (m ² · 24 hours), it will be difficult to maintain the performance of the gas absorbent over a long period of time, and if the gas absorbent is a water vapor absorbent, a large amount of water vapor will be absorbed rapidly. Then, it may generate heat.

  The water vapor permeability of the partition wall material is controlled by the thickness of the resin layer, the manufacturing method, etc., and can be controlled by the thickness. Therefore, on the contrary, the thickness of the resin layer may be appropriately selected according to the target water vapor permeability, and in general, the thickness is preferably about 10 to 40 μm.

  The usage example of the partition material of this invention is demonstrated. For example, two quadrilateral partition materials are prepared in which a fiber layer is laminated on a resin layer made of a polylactic acid polymer. The fiber layer is a non-woven fabric made of a core-sheath composite fiber. The two partition wall materials are overlapped so that the fiber layer is on the inside, a heat seal part is formed on three sides to form a bag body, a gas absorbent is introduced from the opening part, and the opening part is heat sealed. By closing, the gas absorbent filling body filled with the gas absorbent is obtained. When this gas absorbent filling body is stored in a package together with food or the like, the bag body becomes a partition that separates the food and the like from the gas absorber.

  In the above partition material, when the fiber layer is made of a material that does not have thermal bonding performance, such as paper made of natural pulp, the end of the resin layer is arranged so that the resin layer side is on the inner side when overlapping. The part may be melted to form a heat seal part, or the end part may be bonded with another adhesive.

  As another example of use, the packaging material of the present invention may be used to separate the package into two chambers, one containing contents such as food, and the other containing a gas absorbent.

  Examples of the present invention will be described below. In the following examples, each physical property value was determined as follows.

(1) Water vapor permeability (g / (m ² · 24 hours)): Measured under the conditions of 40 ° C. and 90% RH according to the method described in JIS Z-0208 cup method.

(2) Tensile strength (N / 5 cm width): Measured under the conditions of a tensile speed of 200 mm / min and a distance between chucks of 10 cm according to JIS L-1906 strip method. Measurements were made in the longitudinal direction (ie machine direction) and in the transverse direction (ie direction perpendicular to the machine direction).

(3) Tear strength (N): Measured according to the JIS L-1906 pendulum method. Measurements were made in the longitudinal direction (ie machine direction).

(4) Melt flow rate (MFR) (g / 10 min): Measured at a temperature of 210 ° C. and a load of 20.2 N (2.16 kgf) according to the method described in ASTM-D-1238.
Example 1

  A polylactic acid polymer (manufactured by Cargill Dow) with L-lactic acid / D-lactic acid = 96/4 (mol%) and a melting point of 156 ° C. was melt-extruded at a T-die temperature of 230 ° C., and cast into a roll controlled at 25 ° C. Adhesion and rapid cooling were performed to obtain an unstretched film having a thickness of 285 μm. The obtained unstretched film was preheated at 60 ° C. with a preheating roll, then stretched 3.0 times in the longitudinal direction at 75 ° C. using the stretching roll, and subsequently in the transverse direction at a stretching temperature of 80 ° C. in the tenter. The film was stretched 4.0 times. Thereafter, heat treatment was performed at 125 ° C. with a transverse relaxation rate of 5%, and corona treatment was performed to obtain a biaxially stretched film A having a thickness of 25 μm as a resin layer.

The fiber layer was also formed of a polylactic acid polymer. That is, as a polylactic acid-based polymer, an L-lactic acid / D-lactic acid copolymer having a melting point of 171 ° C. and an MFR of 70 g / 10 min and L-lactic acid / D-lactic acid = 99/1 mol% was used. This polymer was mixed with 0.5% by mass of talc as an additive. This mixture was melt-spun from a round spinneret at a spinning temperature of 210 ° C. and a single hole discharge rate of 1.67 g / min. The yarn spun from the nozzle was rapidly cooled, and then taken up at 5000 m / min with an air soccer ball, which was opened and deposited on the collecting surface of a moving conveyor to form a web. Next, the web was passed through a partial thermocompression bonding apparatus composed of an embossing roll, and partially subjected to conditions of a roll temperature of 135 ° C., a crimping area ratio of 14.9%, a crimping point density of 21.9 pieces / cm ² , and a linear pressure of 60 kg / cm. And a long-fiber nonwoven fabric A having a basis weight of 50 g / m ^{2 made} of long fibers having a single yarn fineness of 3.3 dtex as a fiber layer was obtained.

The obtained long fiber non-woven fabric A and the film A are overlapped and passed through a partial thermocompression bonding apparatus composed of an embossing roll, and the roll temperature is 115 ° C., the crimping area ratio is 12.0%, and the crimping point density is 21.9 / cm ^2. The laminate was obtained by partially thermocompression bonding under the condition of a linear pressure of 30 kg / cm.

  Table 1 shows the physical properties of the obtained laminate.

実施例２

Example 2

  L-lactic acid / D-lactic acid = 98.6 / 1.4 mol% L-lactic acid / D-lactic acid copolymer (P1) having a melting point of 168 ° C. and MFR of 70 g / 10 min, and a melting point of 110 ° C. Polybutylene adipate terephthalate polymer (P2) having an MFR of 50 g / 10 min is blended so that P1 / P2 = 80/20 (mass ratio), and polylactic acid polymer-polybutylene adipate terephthalate polymer (P3) was obtained.

  The two types of polymers P1 and P3 are individually weighed so that the core / sheath = 4/1 (mass ratio) using P1 as the core component and P3 as the sheath component, and then the individual Sootsooder type Using an extruder, it was melted at a spinning temperature of 210 ° C., and melt-spun under conditions of a single-hole discharge rate of 1.8 g / min so as to obtain a core-sheath fiber cross section.

  After cooling the spun yarn with a known cooling device, it is subsequently pulverized at a traction speed of 5500 m / min with an air-soccer provided below the spinneret, and opened using a known fiber opening device. And collected as a web on a moving screen conveyor. The single yarn fineness of the deposited composite long fiber was 3.3 dtex.

Subsequently, the web was partially hot-pressed through this web to a partial heat-welding apparatus composed of an embossing roll with a roll temperature of 90 ° C. to obtain a long fiber nonwoven fabric B having a basis weight of 50 g / m ² . For partial thermal welding, an embossing roll with an engraving pattern with an area of 0.6 mm ² and a pressure contact density of 20 points / cm ² and a pressure contact area ratio of 15%, and a metal roll with a smooth surface are used. Using.

The obtained long-fiber nonwoven fabric B and the film A obtained in Example 1 were overlapped and passed through a partial thermocompression bonding apparatus composed of an embossing roll, and the roll temperature was 100 ° C., the crimping area ratio was 12.0%, and the crimping point density was 21. A laminate was obtained by partial thermocompression bonding under the conditions of 9 pieces / cm ² and a linear pressure of 30 kg / cm.

Table 1 shows the physical properties of the obtained laminate.
Example 3

  Crystalline polylactic acid (L-lactic acid / D-lactic acid = 99.0 / 1.0 mol%, weight average molecular weight 200,000, manufactured by Cargill Dow: Nature Works) and amorphous polylactic acid (L-lactic acid / D- A polylactic acid blend was obtained in which the blending ratio of lactic acid = 90.0 / 10.0 mol%, weight average molecular weight 200,000, and Cargill Dow's (Nature Works) was 70/30 mass%. And it mixed so that the compounding ratio of this polylactic acid-type blend body and an aliphatic-aromatic copolymer polyester (BASF company make: Ecoflex F) might be 60/40 mass%. Further, bismethyldiethylene glycol adipate (manufactured by Daihachi Chemical Co., Ltd .: MAX) as a plasticizer is blended in the obtained mixture so as to be 5% by weight based on the total composition, and as an inorganic filler. Measured so that talc (MW HS-T, Hayashi Kasei Co., Ltd., average particle size 2.75 μm) is blended by 15% by mass with respect to the total composition, these were melt-mixed using a twin-screw extrusion kneader A polylactic acid compound raw material was produced at an extrusion temperature of 230 ° C.

  Next, this polylactic acid compound was dried, melted at a temperature of 190 ° C. using a single screw extruder having a diameter of 50 mmφ, extruded from a round die having a die diameter of 100 mmφ, and a film having a thickness of 20 μm by inflation film formation at a blow ratio of 2. B was obtained.

And the obtained film B and the long-fiber nonwoven fabric B obtained in Example 2 were overlapped and passed through a partial thermocompression bonding apparatus composed of an embossing roll, and the roll temperature was 100 ° C., the crimping area ratio was 12.0%, and the crimping point. A laminated body was obtained by partially thermocompression bonding under conditions of a density of 21.9 pieces / cm ² and a linear pressure of 30 kg / cm.

Table 1 shows the physical properties of the obtained laminate.
Example 4

While using polyethylene terephthalate having a melting point of 256 ° C. as a core component, high-density polyethylene having a melting point of 135 ° C. as a sheath component, the core-sheath composition ratio is 1/1, and the melting temperature is 290 ° C. from the core-sheath type composite die. Melt spun. The spun yarn was taken up by air soccer at a spinning speed of 5000 m / min so as to have a fineness of 3.3 dtex, and the drawn fiber was collected on a net so as to become a nonwoven web having a basis weight of 50 g / m ² . Then, the obtained nonwoven web was passed through an embossing device comprising a textured embossing roll having a partial thermocompression bonding ratio of 35% and a smooth roll, and the embossing roll surface temperature was 120 ° C. and the smooth roll surface temperature was 120 ° C. A crimping process was performed to obtain a long fiber nonwoven fabric C.

  A polylactic acid polymer (manufactured by Cargill Dow) with L-lactic acid / D-lactic acid = 96/4 (mol%) and a melting point of 156 ° C. is melted at a T-die temperature of 230 ° C. and extruded to a thickness of 20 μm. Laminated to Nonwoven C. Then, the obtained laminate was passed between a pair of press-contact rolls, and the film and the long fiber nonwoven fabric C were laminated and integrated to obtain a laminate.

Table 1 shows the physical properties of the obtained laminate.
Example 5

  A polylactic acid polymer (manufactured by Cargill Dow) with L-lactic acid / D-lactic acid = 96/4 (mol%) and a melting point of 156 ° C. was melted at a T-die temperature of 230 ° C. and extruded to a thickness of 15 μm. Laminated to the non-woven fabric C obtained in 4. Immediately after that, the film A obtained in Example 1 is overlaid on the polylactic acid laminated on the long fiber nonwoven fabric C to form three layers, which are passed between a pair of press rolls, and two types of films and long fibers. The nonwoven fabric C was laminated and integrated to obtain a laminate.

Table 1 shows the physical properties of the obtained laminate.
Example 6

A polylactic acid polymer (manufactured by Cargill Dow) having a melting point of 156 ° C. with L-lactic acid / D-lactic acid = 96/4 (mol%) was melted at a T-die temperature of 230 ° C. and extruded to a thickness of 20 μm, and a basis weight of 20 g. / M ² paper (natural pulp 100%). Immediately after that, on the polylactic acid laminated on the paper, a polyethylene resin-made weight of 40 g / m ² and a long fiber nonwoven fabric C obtained in Example 4 were layered. Then, the laminate was integrated by passing between a pair of press-contacting rolls to obtain a laminate having a four-layer structure.

  Table 1 shows the physical properties of the obtained laminate.

  Each of the laminates obtained in Examples 1 to 6 is obtained by laminating a resin layer made of a polylactic acid-based polymer and a fiber layer, has a required water vapor permeability, and is used in a package. It was suitable for constituting a partition material.

Claims (5)

A partition material for separating the contents and the gas absorbent in a package containing the contents such as food and the gas absorbent, and including a resin layer made of a polylactic acid-based polymer Bulkhead material used in packaging. The partition material used in the package according to claim 1, comprising a laminate in which a resin layer made of a polylactic acid polymer and a fiber layer are laminated. The partition wall material used in the package according to claim 1 or 2, wherein the water vapor permeability is 100 to 500 g / (m ² · 24 hours) under conditions of 40 ° C and 90% RH. The fiber layer is a nonwoven fabric composed of core-sheath composite fibers, wherein the polymer constituting the sheath part has a melting point lower than the melting point of the polylactic acid polymer constituting the resin layer. Or the partition material used with the package of 3. A gas absorbent filling material, wherein the partition wall material according to any one of claims 1 to 4 is formed in a bag shape and filled with a gas absorbent.