JP2007044079A - Packaging material for body warmer and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an appropriate packaging material for a body warmer using a heat-sealable film made one-hundred percent of plastics by studying methods and conditions for using rips made by pinhole treatment as stable vent holes. <P>SOLUTION: A plurality of ripped pinholes 2 are formed by subjecting a heat-sealable plastic laminate film 1 to pinhole treatment, and the pinholes are treated by pressurizing and heating treatment so as to obtain an air-permeable porous film used as the packaging material for a body warmer. By subjecting the ripped pinholes 2 formed by pinhole treatment of the plastic film to pressurizing and heating treatment, hot-melt parts 3 are partially formed in the ripped pinholes 2 to form stable small pinholes 4. In a method for producing a packaging material for a body warmer, a step for forming a plurality of pinholes by subjecting a heat-sealable plastic laminate film to pinhole treatment and a step for forming an air-permeable porous film by subjecting the pinholes to pressurizing and heating treatment are performed sequentially. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a packaging material for warmers made of a plastic film and a method for producing the same.

  More specifically, the present invention relates to a packaging material for a warmer in which the encapsulated exothermic powder does not leak out from a vent hole, and the aeration rate is stable and uniform, and a method for manufacturing the same.

  As a packaging material for warmers that has been used in the past, the mainstream is a structure in which a sealing material such as polyethylene film is laminated on paper or nonwoven fabric, and vent holes are provided in the sealing film so as not to damage the paper or nonwoven fabric as much as possible. So that it is considered. However, it is easy to remove the release paper by partially providing an uncoated part of the adhesive layer including the peripheral part of the adhesive layer surface, but it is overlapped with the other packaging material that becomes the ventilation surface, the peripheral part When forming a bag for a warmer by heat-bonding each other, the seal pressure on the heat-bonding surface is uneven due to the level difference due to the presence or absence of the pressure-sensitive adhesive layer. There were problems such as spilling.

  In order to solve such a problem, for example, in Patent Document 1, it is easy to remove the release paper at the time of use, and the adhesive is attached so that the heat sealing is surely performed and there is no risk of dust spilling. By using a composite sheet in which a nonwoven fabric is sandwiched between two plastic films as a packaging material for a warmer that can efficiently manufacture a warmer, one side is a heat-bonded surface and the other side is a pressure-sensitive adhesive layer surface. The packaging material has a three-layer structure.

  On the other hand, packaging materials for warmers made only of inexpensive plastic films have also been studied for a long time, but the vent holes made of pinholes provided with the film have become through holes, and the heat generating agent powder is exposed to the outside. At present, there is a concern about leakage and it is not used except for enclosing coarse particles.

  For the purpose of obtaining a stable air hole, various studies have been made on the material of the film. For example, Patent Document 2 is composed of two or more plastic film layers that do not use a nonwoven fabric sheet, at least one surface of which is a heat seal layer. A sheet base material for a warmer is described, wherein the heat seal layer comprises an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methacrylate copolymer having a vinyl acetate content of 10% or more. A sheet base material for body warmers comprising at least one selected from coalescence and low density polyethylene has been proposed.

  Certainly, 100% plastic film packaging materials are inexpensive and can be printed clearly, so they are used in a wide range of fields. The field is greatly expanded if it is possible to provide a uniform air hole that does not leak outside even if it is a fine powder.

  Generally, a vent hole that has been pinhole-treated in a plastic film is a pinhole process during film movement, so it is a slit-like pinhole that is formed by a curved tear rather than a hole by being pulled by the film flow. The porosity changes indefinitely, and the film is squeezed or shaken, so that the powder leaks to the outside or the temperature rises and falls unstable and cannot be used as an appropriate packaging material for warmers. So far, laminated sheets with non-woven fabrics have been widely used.

JP-A-8-98856 JP-A-7-16252

  The inventors of the present invention have arrived at the present invention as a result of various tests and research on means for making a rupture generated by the pinhole treatment into a stable ventilation hole. That is, an object of the present invention is to provide a packaging material suitable for a warmer by a heat-sealable 100% plastic film.

  The packaging material for warmers of the present invention comprises a breathable porous film obtained by forming a large number of pinholes by pinhole treatment of a heat-sealable laminated plastic film and subjecting the pinholes to pressure heat treatment. The slit-shaped pinhole obtained by the pinhole treatment of the plastic laminate film is subjected to pressure heat treatment to form a small hole-shaped pinhole by forming a partial heat-sealed portion of the slit-shaped pinhole. Here, the slit pinhole is a curved tear pinhole, and the tear pinhole is a heat sealing portion formed by partial heat fusion and a small hole pinhole packaging material for warmers .

The manufacturing method is characterized in that a number of pinhole forming steps by pinhole processing of a heat-sealable laminated plastic film and a breathable porous film forming step by pressure heat treatment of the pinholes are sequentially performed.
The pinhole treatment is performed by a combination of a pin roll and a rubber roll or a brush roll so that the direction in which the pin is inserted is directed from the high-melting film side to the low-melting film side for sealing. Also,
The pinhole pressure heat treatment is a method for producing a packaging material for warmers that is performed in a range of a pressure temperature of 70 to 130 ° C. and a pressure of 0.5 to 1.5 kg / cm ² by a combination of a heat roll and a rubber roll.

  According to the present invention, a curved tear formed by pinhole processing on a plastic film is subjected to a pressure heat treatment at an appropriate temperature and pressure, so that several fusion parts are formed, and several cracks are formed in one tear. Thus, a packaging material for a warmer made of only a plastic film suitable for a warmer that does not leak powder and has a stable opening degree is obtained.

  Examples of the 100% plastic film used in the present invention include a composite film composed of a film having a relatively high melting point such as polyester, nylon, and polypropylene and a sealing material represented by low melting point polyethylene. The thickness of the sealing material layer is 20 to 150 μm, preferably 30 to 100 μm, in order to generate appropriate air holes by pressure heat treatment.

  In order to efficiently carry out the present invention, a combination of a pin roll and a rubber roll or particularly a brush roll is preferable. Moreover, it is preferable that the direction to stab the pin is directed from the film side having a high melting point to the film side for sealing. All of these conditions are suitable for making several fused portions at the pinhole crevice.

  In addition, although there is a correlation between an appropriate pin diameter and the depth of insertion, the diameter of the pinhole crack to be generated is preferably in the range of about 0.1 to 0.5 mm. If the diameter is 0.1 mm or less, powder leakage is a good result. However, in order to obtain an appropriate air permeability, the number of pins becomes enormous, which makes it difficult to manufacture pin rolls. On the other hand, when the diameter is 0.5 mm or more, there is a risk of powder leakage even if a fused part is formed by pressure heat treatment.

The pressure heat treatment can be suitably performed by a combination of a heat roll and a rubber roll. The pressure heat temperature varies depending on the running speed of the film or the kind of the sealing film, but the range of 70 to 130 ° C. is appropriate, and the pressure is 0.5 to 1.5 kg / cm ² to achieve the object of the present invention. .

  A warmer that uses a packaging material that is simply a pinhole treatment compared to a conventional 100% film sheet can easily change the ventilation conditions depending on the winding pressure, and is extremely insensitive to temperature characteristics and powder leakage. Although it was difficult to produce a stable and stable product, according to the present invention, a stable and beautiful body warmer can be used at low cost, and the breathable packaging material of the present invention is It can be widely used for products encapsulating fine powders, such as deenzymes and desiccants.

  Since the packaging material for warmers of the present invention has a stable ventilation performance only with a laminated film without using a non-woven fabric, there is an advantage that it can be supplied at a low price.

  The present invention will be specifically described below with reference to the drawings and examples. FIG. 1 is a flowchart showing the manufacturing process of the packaging material for warmers of the present invention. FIG. 2 is a mimetic view of a photomicrograph of a tear produced in a pinhole treated plastic film. FIG. 3 is a mimetic view of a micrograph obtained by heat-treating a crack formed in a plastic film at 110 ° C.

  As seen in FIG. 1, a pinhole treatment is performed during winding and running of a heat-sealable plastic laminate film 1 (for example, a polyester-polyethylene composite film) serving as a packaging material. As a result, a slit-shaped pinhole film is formed in which a large number of slit-shaped pinholes 2 with curved tears are formed. An example of this is shown in FIG. 2. Since the pinhole 2 is a slit, a relatively large hole is formed when the film is turned inside the curved slit, and the contents leak out. In the present invention, this slit-shaped pinhole film is passed between heating rolls to perform pressure heat treatment of the pinhole. As a result, as shown in FIG. 3, a part of the curved split-shaped pinhole 2 is thermally fused. Part 3 is formed, and the generation of holes due to the continuous tearing is eliminated. By forming the small hole-shaped pinhole 4 divided by the heat fusion part 3, it becomes a proper air hole and a packaging material for a warmer porous film with no leakage of contents. Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
The pin shape is 0.70mm in diameter, the diameter 1.5mm from the tip is 0.45mm, the diameter at 3.0mm is 0.55mm, and the nail-shaped pin projection that becomes 0.7mm at 7.5mm is 3mm Like this, between a 76 mm pin roll arranged at a pitch of 3 mm and a brush roll of the same diameter, a 190 mm wide polyester 12 μm and polyethylene film 40 μm heat-sealable laminate film is only pierced to a depth of 1.5 mm. The pinhole processing was performed at a speed of 50 m / min. By this treatment, as shown in FIG. 2, a curved split pinhole 2 having a diameter of 0.4 to 0.45 mm was generated in the laminate film 1. Subsequently, pressure heat treatment was performed with a heat roll and a rubber roll at 110 ° C. under 1.0 kg / cm ² . As a result, as shown in FIG. 3, a part of the curved split pinhole 2 was a continuous body of the heat fusion portion 3 and the small hole pinhole 4.

  The air-permeable porous film packaging material thus obtained was cut to a length of 130 mm, and a 100-250 mesh sponge-like iron powder, silicon dioxide powder and vermikinilite powder, and a 15% saline solution. Disposable body warmer A was prepared by enclosing 50 g of a heat-generating agent mixed in a three-sided seal.

  The resulting warmer does not leak the exothermic powder outside even if it is shaken, and has a comfortable temperature characteristic with a maximum temperature of 66 ° C and a duration of 18 hours or more as measured by JIS-S4100. It was a thing.

Examples 2 and 3
Cairo B and C were prepared in the same manner as in Example 1 for the air-permeable packaging material wound up to 500 m that was pinhole-treated under the conditions of Example 1 at the position of 200 m and 500 m from the beginning. . Even if they were shaken or shaken, the exothermic agent did not leak outside, and the temperature characteristics were appropriate as shown in Table 1, and a uniform warmer could be made.

Example 4
Between the pin roll similar to Example 1, and the brush roll, the pinhole process was performed using the heat-sealable laminated film 1 of 190 micrometers width polypropylene 15micrometer and polyethylene film 40micrometer. By this treatment, a curved split pinhole 2 having a diameter of 0.43 to 0.49 mm was generated. Subsequently, pressure heat treatment was performed at 105 ° C. with a heat roll and a rubber roll at 1.0 kg / cm ² . A disposable body warmer D was made using the obtained laminate film 1 in the same manner as in Example 1, and the leakage and temperature characteristics of the powder were tested in the same manner as in Example 1. The results were good as shown in Table 1.

Comparative Example 1
Cairo E was prepared in the same manner as in Example 1 except that the pressure heat treatment was omitted. In Cairo E, the exothermic agent leaked out by shaking about 10 times, and the maximum temperature was 74 ° C. and the duration was 11 hours.

Comparative Examples 2 and 3
In the same manner as in Comparative Example 1, the wound breathable packaging material that is not subjected to the heat treatment of 500 m is the same as in Example 1 and Comparative Example 1, respectively. , G were prepared. In F and G, the exothermic agent leaked to the outside, or the temperature characteristics varied greatly.

  As is clear from the above examples and comparative examples, a warmer using a packaging material that is only subjected to pinhole processing can easily change the aeration conditions depending on the winding pressure, which can cause temperature characteristics and powder leakage. On the other hand, it is extremely unstable and it is difficult to make a product with a stable standard.

  On the other hand, according to the present invention, a stable and beautiful body warmer can be used at low cost, and the breathable packaging material of the present invention can be used for products enclosing fine powders such as oxygen scavengers and desiccants. It can be widely used.

It is a flowchart which shows the manufacturing process of the packaging material for warmers of this invention. It is an imitation figure of the photomicrograph of the tear which arose in the plastic film which carried out the pinhole process. It is a mimetic diagram of the micrograph which carried out the pressure heat treatment at 110 degreeC in the crack which arose in the plastic film.

Explanation of symbols

1 Laminate film 2 Split pinhole 3 Heat fusion part 4 Small hole pinhole

Claims (6)

  A packaging material for body warmers comprising a breathable porous film obtained by forming a large number of pinholes by pinhole treatment of a heat-sealable laminated plastic film and subjecting the pinholes to pressure heat treatment.   The packaging material for a warmer according to claim 1, wherein the slit-shaped pinhole obtained by pinhole treatment of a plastic film is a small hole-shaped pinhole formed by partial heat fusion of the slit-shaped pinhole by pressure heat treatment.   The packaging material for a warmer according to claim 2, wherein the slit-like pinhole is a curved tear-like pinhole, and the tear-like pinhole is a heat fusion part formed by partial thermal fusion and a small hole-like pinhole. .   A method for producing a packaging material for a warmer, comprising sequentially performing a plurality of pinhole forming steps by pinhole treatment of a heat-sealable laminated plastic film, and a breathable porous film forming step by pressure heat treatment of the pinholes.   The method for producing a packaging material for a warmer according to claim 4, wherein the pinhole treatment is performed by a combination of a pin roll and a rubber roll or a brush roll so that the direction of sticking the pin is directed from the high melting point film side toward the low melting point film side for sealing. The method for producing a packaging material for a warmer according to claim 4, wherein the pinhole pressure heat treatment is performed at a pressure temperature range of 70 to 130 ° C and a pressure range of 0.5 to 1.5 kg / cm ² by a combination of a heat roll and a rubber roll.

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