JP4468457B2 - Laminated porous substrate and disposable cairo - Google Patents

Description

  The present invention relates to a breathable laminated porous substrate that is excellent in long-term stability of printed contents, and a single-use warmer using the same.

  Conventionally, as a laminated porous substrate printed with air permeability that can be used for a storage bag of a single use warmer, a porous film and an air permeable substrate are bonded through a porous adhesive layer (special Japanese Laid-Open Patent Application No. 8-131472) has been known in which an outer surface is subjected to a printing process.

  In the above-described processing by printing, in the decorative processing such as embossing or hot stamping, a laminated porous base material is perforated, and when it is used as a disposable body warmer, a through-hole causing a heat generation abnormality is generated and low temperature burns are caused. In some cases, the purpose is to prevent it.

  However, in the printing process on the outer surface by the conventional method, the printed layer is easily dropped and it is difficult to maintain the printed content during the period of use, the printed content is difficult to see clearly, and the air permeability is adversely affected. There were problems such as lowering the temperature and duration of heat generation.

  In other words, a storage bag for a single-use warmer is usually formed with a porous film on the inside and a breathable substrate on the outside. When printing on the outer surface (inside the bag) of the porous film, water vapor generated from the heating element, etc. The printing ink is easy to peel off, and the printed content is obscured and lacks clarity, and there is a problem that the air permeability is lowered when printing a pattern or the like. On the other hand, in printing on the outer surface (outer side of the bag) of the breathable base material, there is a problem that the printed layer is severely dropped due to rubbing or the like, and the printed content is likely to be distorted due to fluffing.

JP-A-8-131472

  The present invention is less likely to cause the printing layer to fall off or be confused, maintain the printed content for a long period of time and can be clearly visualized, and is the same as when there is no printed layer with good air permeability even when printing a pattern or the like. It is an object of the present invention to obtain a laminated porous substrate and a disposable body warmer that maintain an exothermic temperature and an exothermic duration.

The present invention comprises a porous film formed by stretching a film containing a polyolefin resin and an inorganic filler and a non-woven fabric bonded through a breathable adhesive layer formed by fiberizing a polyamide hot melt adhesive , and the porous receiving one or both of quality film and the nonwoven fabric is used in at least a portion of the disposable and characterized by having a printed layer on the bonding surface side Cairo laminate porous substrate, and a disposable hand warmer for laminated porous substrate The present invention provides a single-use warmer characterized by containing a heating element inside a bag.

According to the present invention, the printed layer is protected by a porous film or a breathable base material, and is less likely to drop off or become dull due to water vapor or rubbing, etc. A laminated porous substrate that maintains good air permeability even in large-area printing can be obtained, and a single-use warmer that maintains the same exothermic temperature and exothermic duration as when there is no printed layer can be obtained.

  In addition, the protective function of the breathable base material, etc., protects the printing layer even in the manufacturing process such as the disposable body warmer in addition to the base material laminating process, and can prevent the disappearance of the printed layer. Are better. In addition, in the case of bonding treatment with an adhesive layer consisting of a fiber accumulation layer, it is excellent in adhesive strength, moisture permeability stability and heat resistance, and it is difficult to cause wrinkles and peeling even as a disposable body warmer, cushioning due to the adhesive layer, etc. Based on the excellent texture.

  The laminated porous substrate according to the present invention is obtained by bonding a porous film and a breathable substrate through a breathable adhesive layer, and one or both of the porous film and the breathable substrate are printed on the adhesive surface side. It consists of what has. An example thereof is shown in FIG. 1 is a porous film, 2 is a breathable adhesive layer, 3 is a breathable substrate, and 31 is a printing layer.

  The porous film and the breathable substrate used for the formation of the laminated porous substrate can conform to conventional single use warmers and are not particularly limited. By the way, as an example, polyethylene, and in particular, an inorganic filler such as calcium carbonate, especially those having an average particle size of 30 μm or less are blended with polyolefin resins such as linear low density polyethylene and polypropylene as appropriate, such as an extrusion method. A porous film formed by stretching a film in a uniaxial or biaxial manner, or a non-woven or felt-like breathable substrate made of polyamide fiber, polyester fiber, polypropylene fiber or the like Etc.

The porous film which can be preferably used from the point of moderate exothermicity due to air permeability when used as a disposable body warmer has an average pore diameter of 0.1 to 10 μm and a moisture permeability of 100 to 1500 g / m ² · day. A breathable substrate that can be preferably used is a nonwoven fabric having a basis weight (weighing) of 10 to 100 g / m ² .

  A laminated porous substrate can be formed by adhering a porous film and a breathable substrate through an appropriate breathable adhesive layer. In the bonding process, a predetermined printing process is applied to the bonding surface side in advance. Porous films and / or breathable substrates are used.

  Therefore, the porous film and / or the breathable substrate must have a printing layer on the bonding surface side, but the printing process can be performed at an appropriate stage until immediately before the bonding process. it can. Therefore, a porous film or / and a breathable substrate that has been subjected to a printing process in a separate process before the bonding process may be used, or a printing process may be performed on the porous film or / and the breathable substrate in the bonding process. Adhesion treatment may also be performed.

  In the above, the printing layer can be formed by an arbitrary method such as a gravure method, a screen method, or a flexo method. In addition, as the printing ink, for example, any ink such as a water-based or oil-based medium-based ink, an ultraviolet curable ink, or the like can be used.

  In addition, the contents of printing are also optional. For example, characters such as product names, serial numbers and manufacturer names, patterns such as polka dots, figures such as character diagrams, symbols such as barcodes, characters, figures and symbols combined, etc. The print contents may be appropriate. The printed layer is generally composed of a colored layer from the viewpoint of visibility, and in particular, it is generally composed of a colored layer excellent in contrast with the porous film and / or the breathable substrate. It is not limited.

  The printing layer can be provided on one or both of the porous film and the breathable substrate as described above. Even when a laminating porous substrate with a printed layer on the adhesive surface side of the porous film is used as a disposable body warmer so that the porous film is inside the storage bag, the breathable substrate and the air The printed content on the porous film can be visually recognized with good legibility through the adhesive layer. It is preferable to provide a printing layer on the adhesive surface side of the breathable base material from the viewpoint of clear visibility of the printed content when the disposable body warmer is used.

  The breathable adhesive layer for adhering the porous film and the breathable substrate can be formed of an appropriate adhesive layer showing air permeability, such as a pattern coating adhesive layer or a hot-melt type porous adhesive film. . Relative to the fineness and uniform distribution of the pores, there is little bias in air permeability and adhesive force, and from the point of adhesion processing that is excellent in texture, etc., the adhesive substance is made into fibers and deposited in a nonwoven fabric or entangled fiber Adhesion treatment via an adhesive layer is preferred.

  The air-permeable adhesive layer is formed by, for example, an adhesive substance by an appropriate method such as the curtain spray method, the melt blow method, or the slot spray method illustrated in FIG. 4 is made into a fiber by using an adhesive material such as a method in which fiber 4 is made into a porous adhesive layer 2 by spreading and depositing it on a suitable support substrate made of a porous film, a breathable substrate, a separator or the like. And can be performed by an appropriate method of arranging it in a porous state. By making the adhesive substance into a fibrous form under heat melting, the odor is evaporated and the odor is excellent.

  In the curtain spray method shown in the figure, the air-permeable base material 3 having the printing layer 31 is sequentially fed from the take-up roll 32 while the adhesive substance 4 in the sealed container is heated and melted and supplied to the die 5. Then, the air-permeable base material 3 in which the adhesive substance melted by blowing hot air from above the die as shown by the arrow is converted into a fiber 41 from the spray head 51 and blown out in a curtain shape, which is sequentially moved via the conveyor 6. An adhesive layer 2 having a non-woven porous structure formed by spreading and coating the fibers on the printed layer 31 is formed, and the porous film 1 sequentially fed from the winding roll 11 is disposed thereon. Then, it is subjected to an adhesive treatment via the pinch roll 61 and wound on the take-up roll 71, and the target laminated porous substrate 7 is formed in a series of the same steps.

The breathable adhesive layer that is more preferable than the balance between the adhesive force and the breathability is such that the average diameter of the fibers forming the adhesive layer is 0.1 μm to 1 mm, especially 0.5 to 100 μm, especially 1 to 50 μm. fibers of such mean diameter basis weight of 100 g / m ² or less, especially 1 to 30 g / m ^2, was deposited in the nest-like porous structure of the nonwoven fabric-like or tangled fibrous or spider particular in a proportion of 2 to 10 g / m ² Is. The average fiber diameter can be determined by, for example, a method of taking a photograph of a breathable adhesive layer randomly with a scanning microscope and calculating an average value of fiber diameters at arbitrary 10 points.

  The laminated porous substrate was formed by forming a breathable adhesive layer on a porous film and / or a breathable substrate and laminating them as in the method of FIG. 2 described above, or on a separator. The breathable adhesive layer can be transferred to an adhesive surface of the porous film or / and the breathable substrate, and can be performed by an appropriate method such as a method of laminating through the transfer layer. Appropriate treatments such as corona treatment, plasma treatment, sputter etching treatment, anchor treatment with primer, etc. are applied to the adhesive surface of the porous film or breathable substrate as necessary for the purpose of improving the adhesive strength. You can also.

  Examples of the adhesive material for forming the fiber include those that can be heated and melted, such as hot-melt type pressure-sensitive adhesives or adhesives, and exhibit adhesiveness at normal temperature or when heated and melted, or when the heated melt is fiberized. Alternatively, an appropriate material such as a material that exhibits adhesiveness by reheating the formed fiber can be used.

  Incidentally, examples of the adhesive substance include styrene elastomers such as SIS, SBS, SEBS and SIPS, polyethylene, particularly ultra-low density polyethylene and polypropylene, olefin polymers such as ethylene / vinyl acetate copolymer, acrylic acid and methacrylic acid. Examples thereof include an acrylic polymer having an alkyl ester such as an acid as a component, and a thermoplastic resin such as a polyester, polyamide or urethane as a component.

  In particular, the pores of the porous film are blocked and the air permeability is likely to be reduced, so that low-molecular weight components do not bleed out due to changes over time and are excellent in storage stability. Adhesive substances that can be preferably used from the viewpoint of heat resistance and the like that can prevent the generation of wrinkles between the porous film and the breathable substrate due to heat generation, include hot-melt polyamide copolymers and reactive polyurethanes. Ingredients.

  The adhesive substance can be used alone or in combination of two or more. In preparation of the adhesive substance, appropriate additives such as an adhesion-imparting agent, a softening agent and an anti-aging agent are blended as necessary for the purpose of adjusting the melt viscosity, dynamic elastic modulus, adhesive properties, etc. be able to. Incidentally, tack and strength can be adjusted by adding an olefin polymer to a styrene elastomer.

  In addition, as said adhesiveness imparting agent, for example, one or two kinds of appropriate materials such as styrene-based resin, rosin-based resin, petroleum-based resin, terpene-based resin, hydrogenated products thereof, or partially hydrogenated products thereof are used. The above can be used. As the softening agent, for example, paraffins, polybutene, polyisobutylene, terpene-based oils, hydrogenated products thereof, partial hydrogenated products, or the like can be used alone or in combination.

  In the present invention, an adhesive substance that can be preferably used from the standpoints of maintaining the fiber state, preventing clogging of the porous film, preventing the clogging of the porous film, and forming a uniform fiber during application via a hot melt applicator, It is prepared so that the melt viscosity, particularly at 90 to 250 ° C., is less than 1500 poise, especially 20 to 500 poise, especially 50 to 200 poise.

  The porous film, the breathable substrate and the breathable adhesive layer forming the laminated porous substrate according to the present invention can be blended with an antibacterial agent as necessary for the purpose of improving hygiene by an antibacterial action. .

  The laminated porous substrate according to the present invention can be preferably used for various applications that are required to have air permeability such as a storage bag for a single use warmer. An example of the single-use cairo is shown in FIG. This is because the heat-seal layer 81 and the laminated porous substrate of the storage bag formed by heat-sealing the peripheral edge of the porous film 1 of the heat-seal layer 81 and the laminated porous substrate 7 in the heat-generator-containing substrate 8. The heating element 9 is accommodated in the gap between the two and sealed. Reference numeral 83 denotes an adhesive layer for adhering to clothing and the like, and 84 denotes a separator for temporarily protecting it.

  In addition to the heat-sealing method, the above-described storage bag is applied to an appropriate method according to the prior art, such as a method of forming the bag body by combining the end portions of the base material by an appropriate method such as adhesive or sewing. In this case, the disposable body warmer according to the present invention may be formed by using the laminated porous substrate according to the present invention at least partially for the purpose of air permeability. Therefore, the use location can be an appropriate location such as the entire surface, one surface, or a part of the storage bag.

  The heating element stored in the bag is also in contact with oxygen (air) taken in based on the breathability of the storage bag, such as a ventilation exothermic composition composed of metal powder, water, water retention agent, oxidation accelerator, etc. Any suitable heating element can be used, such as those that generate heat, and any heating element in a conventional single-use warmer can be used.

Example 1
A polyamide hot melt adhesive (melt viscosity 100 poise) melted at 180 ° C. in an applicator tank on a printed layer composed of a polka dot pattern made of UV curable ink applied on a polyamide nonwoven fabric with a basis weight of 40 g / m ² The fiber is spread and deposited using a curtain spray system, and a non-woven breathable adhesive layer with a basis weight of 7 g / m ² is formed, and a porous film is laminated on it to continuously form a laminated porous substrate. did.

In the above, the average fiber diameter in the breathable adhesive layer was about 10 μm. The porous film is made by extruding 100 parts by weight of linear low density polyethylene and 120 parts by weight of calcium carbonate on the same production line to form a film, and laminating it while stretching it four times uniaxially. The average pore diameter is 0.5 μm, and the moisture permeability is 600 g / m ² · day.

Comparative Example A laminated porous substrate was obtained in the same manner as in Example 1 except that the polyamide-based nonwoven fabric was used so that the printed layer was on the outside of the laminate.

Evaluation test Regarding the laminated porous substrates obtained in the examples and comparative examples, the change in air permeability depending on the presence or absence of the printed layer was examined, and a disposable warmer according to FIG. And the change of the sharpness at the time of practical use of Cairo was investigated, and comprehensive evaluation of practicality was performed.

  The results are shown in the following table.

Cross-sectional view of laminated porous substrate example Illustration of manufacturing process example Cross-sectional view of a single-use Cairo example

Explanation of symbols

7: Laminated porous substrate 1: Porous film 2: Breathable adhesive layer 3: Breathable substrate 31: Print layer 9: Heating element

Claims (4)

The porous film and the nonwoven fabric formed by stretching a film comprising a polyolefin resin and the inorganic filler makes it a polyamide based hot melt adhesive adhered through the breathable adhesive layer formed by fiberizing, the porous film and the nonwoven fabric One or both of them have a printed layer on the adhesive surface side, a laminated porous substrate for disposable warmers . In Claim 1 , the air-permeable adhesive layer is composed of a deposited layer having a basis weight of 1 to 30 g / m ² of fibers having a diameter of 1 to 50 µm, and the porous film has an average pore diameter of 0.1 to 10 µm and a moisture permeability of 100. A laminated porous substrate for single- use warmers that is ˜1500 g / m ² · day. 3. The laminated porous substrate for disposable warmers according to claim 1 or 2, wherein the printed layer comprises a colored layer of characters, figures, symbols or a combination thereof. Cairo disposable and characterized by being accommodated inside the heating element storage bag used for at least part of the circuit laminated porous substrate disposable according to claim 1-3.

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