JP5808086B2 - Disposable body warmer - Google Patents

Description

  The present invention relates to a disposable body warmer. More specifically, the present invention relates to a disposable warmer that quickly warms up after reaching the target temperature after opening the outer bag.

  Conventionally, a type of warmer that is applied to clothes or skin (sometimes referred to as “paste warmer”), or a type of warmer that is not applied (cannot be pasted) by handcuffing (“cannot be applied”) In some cases, disposable warmers such as the As the disposable body warmer, there are a wide variety of disposable body warmers in which two bag members are formed into a bag body using heat sealing means, and a heating element mainly composed of iron powder or the like is enclosed in the bag body. It is used.

  In these disposable warmers, from the viewpoint of oxygen supply to the heating element inside the bag body, a breathable member is used as at least one of the bag structural members, and in particular, a composite member (lamination of a porous film and a nonwoven fabric) A breathable bag constituting member is widely used (see, for example, Patent Documents 1 to 3).

As a nonwoven fabric used for the above-mentioned air-permeable bag constituting member, conventionally, nonwoven fabrics having a basis weight of 30 g / m ² , 35 g / m ² , 40 g / m ² or the like have been mainly used. These nonwoven fabrics are excellent in the basis weight uniformity and excellent in processability and strength. However, the disposable body warmers manufactured by using these non-woven fabric bag members are the time required to reach the target temperature after opening the outer bag individually packaging the disposable body warmers (sometimes referred to as “rise time”). There was a problem that took a relatively long time.

Japanese Patent Laid-Open No. 10-328224 JP 2000-42021 A JP 2000-126217 A

  Accordingly, an object of the present invention is to provide a disposable body warmer that has a short rise time and warms quickly in a short time during use.

  As a result of intensive studies to achieve the above object, the inventor of the present invention has a low basis weight and a partial basis weight (weight per unit area) variation as a non-woven fabric of a bag constituting member composed of a composite member of a porous film and a non-woven fabric. It has been found that by using a non-woven fabric having an excellent disposable warmer with a short rise time during use, the present invention has been completed.

That is, the present invention is characterized by having a bag-constituting member comprising a nonwoven fabric and a porous film having a basis weight of 10 g / m ² or more and less than 30 g / m ² and having a minute basis weight variation of 8% or more. Provide disposable body warmers. In addition, 6 to 12 square measurement samples having a length of 25 mm and a width of 25 mm are collected from the nonwoven fabric, the basis weight is measured, the basis weight standard deviation (σ) and the average value (AVE) are calculated, and the average value is calculated. The ratio (percentage:%) [(3σ / AVE) × 100] of the value obtained by multiplying the standard deviation by 3 is defined as the “fine weight variation”.

  Since the disposable body warmer of the present invention uses a bag constituting member having a non-woven fabric having a small basis weight and a partial basis weight variation and a porous film, the rise time during use is short, and the conventional disposable body warmer It warms faster than it is.

It is the schematic (cutting part end view) which shows an example of the disposable warmer (paste warmer) of this invention. It is explanatory drawing (schematic plan view) which shows typically the collection method (an example) of the sample for a measurement in the measurement of the variation | variation of a minute fabric weight. It is a schematic plan view which shows the disposable body warmer (inner bag) obtained by the Example and the comparative example. It is explanatory drawing (schematic top view) which shows typically the collection method of the sample for a measurement in the measurement of the fabric weight of a nonwoven fabric in the Example and a comparative example, and the variation of the micro fabric weight.

The disposable body warmer of the present invention is a bag-constituting member comprising a nonwoven fabric and a porous film having a basis weight of 10 g / m ² or more and less than 30 g / m ² and a fine basis weight variation of 8% or more (member constituting the bag body). As an essential component. In the present specification, the above-mentioned “nonwoven fabric having a basis weight of 10 g / m ² or more and less than 30 g / m ² and a fine basis weight variation of 8% or more” may be referred to as “nonwoven fabric (a)”. In addition, “a bag-constituting member comprising a nonwoven fabric (a) having a basis weight of 10 g / m ² or more and less than 30 g / m ² and a fine-mesh variation of 8% or more” and a porous film is referred to as “bag-constituting member (b ) ".

  The disposable body warmer of the present invention is preferably formed by heat-sealing two or more (more preferably two) bag member members including the bag member member (b). More specifically, a bag body is formed by heat-sealing two or more (preferably two) bag body constituent members, and a heating element is enclosed inside the bag body (see FIG. 1). The disposable body warmer of the present invention may be composed of two or more bag body constituent members (b), or a bag body constituent member (b) and a bag body constituent member other than the bag body constituent member (b) (" It may be referred to as “other bag member”. In the present specification, a bag body in which the heating element is enclosed may be referred to as an “inner bag”.

[Bag member (b)]
The bag body structural member (b) in the disposable body warmer of the present invention is an essential bag body structural member. The said bag body structural member (b) contains a nonwoven fabric (a) (nonwoven fabric layer) and a porous film (porous film layer). That is, it is a composite member in which the nonwoven fabric (a) and the porous film are laminated. The nonwoven fabric (a) and the porous film are preferably bonded via an adhesive layer, and more preferably bonded via a porous adhesive layer formed by fiberizing the adhesive. preferable. In addition, it is preferable that a bag body structural member (b) contains only one nonwoven fabric (a) as a nonwoven fabric (nonwoven fabric layer).

  The laminated structure (composite structure) of the bag-constituting member (b) is not particularly limited, but is preferably a structure in which one surface side is a porous film and the other surface side is a nonwoven fabric (a). Specifically, a laminated structure of porous film / adhesive layer (particularly porous adhesive layer) / nonwoven fabric (a) is preferable.

(Nonwoven fabric (a))
The nonwoven fabric (a) is not particularly limited. For example, polyamide nonwoven fabric (nylon nonwoven fabric, etc.), polyester nonwoven fabric, polyolefin nonwoven fabric (polypropylene nonwoven fabric, polyethylene nonwoven fabric, etc.), rayon nonwoven fabric, etc. Or conventional nonwoven fabrics (nonwoven fabrics made of natural fibers, nonwoven fabrics made of synthetic fibers, etc.). Among these, from the viewpoint of texture, a nylon nonwoven fabric (also referred to as a nylon nonwoven fabric, the same applies to others) and a polyester nonwoven fabric (in particular, a polyethylene terephthalate nonwoven fabric) are preferable.

  The production method of the nonwoven fabric (a) is not particularly limited. For example, the spun bond method (spun bond method), the spun lace method (spun lace method), the needle punch method, the chemical bond method, the thermal bond method, the stitch bond method, The melt blow method etc. are mentioned. Among these, the spunbond method and the spunlace method are preferable from the viewpoint of increasing the variation in the minute weight in the low weight area and easily achieving the variation in the basis weight and the minute weight defined in the present invention. That is, the nonwoven fabric (a) is preferably a nonwoven fabric (spunbond nonwoven fabric) manufactured by a spunbond method or a nonwoven fabric (spunlace nonwoven fabric) manufactured by a spunlace method.

The basis weight (weight per unit area) of the nonwoven fabric (a) is 10 g / m ² or more and less than 30 g / m ² , preferably 12 to 25 g / m ² , more preferably 15 to 23 g / m ² . By setting the basis weight to be less than 30 g / m ² , the rise time can be sufficiently shortened, and the warm feeling during use (experience temperature) can be increased. When the basis weight is 30 g / m ² or more, the rise time cannot be sufficiently shortened even if the variation in the micro basis weight is large. Furthermore, when the basis weight is less than 30 g / m ² , it becomes easy to achieve the minute basis weight variation defined in the present invention, which is preferable. Moreover, the workability and strength of the nonwoven fabric (a) are improved by setting the basis weight to 10 g / m ² or more. If the basis weight is less than 10 g / m ² , the nonwoven fabric is likely to be perforated or cut in the processing step. The basis weight (weight per unit area) of the non-woven fabric (a) is an average value (AVE) of the basis weight (micro basis weight) obtained in the measurement of “minute variation in micro basis weight” described later.

  The variation in the fine weight of the nonwoven fabric (a) is 8% or more, preferably 8 to 50%, more preferably 8 to 30%, and further preferably 8 to 15%. The rise time can be sufficiently shortened by setting the variation in the minute weight to 8% or more.

The above-mentioned “small variation in fabric weight” is obtained by measuring 6 to 12 square measurement samples having a length of 25 mm and a width of 25 mm from a nonwoven fabric, measuring the fabric weight (micro fabric weight), and calculating the standard deviation (σ) of the fabric weight. When the average value (AVE) is calculated, it is a ratio (percentage:%) [(3σ / AVE) × 100] of a value obtained by triple the standard deviation with respect to the average value. More specifically, for example, it can be measured and calculated by the following method.
<Measurement and calculation method of variation in minute weight of nonwoven fabric (a)>
As shown in FIG. 2, twelve square nonwoven fabrics (a) having a length of 25 mm and a width of 25 mm are sampled from the disposable body warmer (bag body component (b)) of the present invention, and used as measurement samples. If the disposable body warmer is small and 12 measurement samples cannot be collected, the maximum number of measurement samples that can be collected is used (however, the number of measurement samples is 6 or more). The measurement sample is collected from a portion of the bag constituting member (b) that is not heat-sealed (sometimes referred to as a “non-heat-sealed portion”).
FIG. 2 is an explanatory diagram (schematic plan view) schematically showing an example of a method for collecting a measurement sample. In FIG. 2, 21 is a disposable body warmer of the present invention (an example), 22 (part shown by hatching) is a heat seal part (part where heat seal is applied), 23 is a non-heat seal part, 24 (shown by a dot pattern) Represents a measurement sample (one piece).
Next, the weight of each measurement sample is measured, the weight per unit area (unit: g / m ² ) is calculated, and the basis weight of each measurement sample (referred to as “micro basis weight”) is calculated.
Further, the standard deviation (σ) and the average value (AVE) of the fine weight per unit are calculated for all the collected measurement samples (in principle, twelve), and according to the following formula, the “fineness per unit variation” of the nonwoven fabric (a) is calculated. Is calculated.
Variation in minute weight (%) = (3σ / AVE) × 100
Further, the average value (AVE) of the above-mentioned minute basis weight is defined as “the basis weight (weight per unit area) of the nonwoven fabric (a)”.

  The said nonwoven fabric (a) may have any form of a single layer and a multilayer. Moreover, the nonwoven fabric (a) may be comprised only from 1 type of fiber, and may be comprised combining multiple types of fiber. Furthermore, in the nonwoven fabric (a), the fiber diameter, fiber length and the like are not particularly limited.

  The non-woven fabric (a) is selected from commercially available non-woven fabrics by selecting the micro-mesh variation and basis weight within the specified range of the present invention according to the above-mentioned “Measurement and calculation method of micro-mesh variation”. You can also. As a commercial item, Asahi Kasei Fibers Co., Ltd. make, brand name "Eltas E01020" (polyester spunbond nonwoven fabric), brand name "Eltus N03025" (nylon spunbond nonwoven fabric), etc. are mentioned, for example.

(Porous film)
The porous film is a film-like porous substrate composed of a polyolefin resin, a polyester resin, a polystyrene resin, or the like. Among these, a porous film composed of a polyolefin resin is preferable from the viewpoints of price, flexibility, and heat sealability. Furthermore, the porous film is preferably a porous film formed by making an unstretched film porous by constituting a polyolefin resin and an inorganic filler as essential components.

  The polyolefin-based resin is a monomer of at least an olefin component (such as ethylene, propylene, butene-1, pentene-1, hexene-1, 4-methyl-pentene-1, heptene-1, octene-1, etc. α-olefin). Resin as a component. Examples of the polyolefin resin include low density polyethylene, linear low density polyethylene (linear low density polyethylene), medium density polyethylene, high density polyethylene, and ethylene-α-olefin copolymer (for example, ethylene-propylene copolymer). In addition to polyethylene resins such as polymers), polypropylene resins (polypropylene, propylene-α-olefin copolymers, etc.), polybutene resins (polybutene-1, etc.), poly-4-methylpentene-1, etc. Can be mentioned. Examples of polyolefin resins include ethylene-unsaturated carboxylic acid copolymers such as ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers; ionomers; ethylene-methyl acrylate copolymers, ethylene- Ethylene- (meth) acrylic ester copolymers such as ethyl acrylate copolymer and ethylene-methyl methacrylate copolymer; ethylene-vinyl acetate copolymer; ethylene-vinyl alcohol copolymer can also be used. . As the polyolefin-based resin, a polyethylene-based resin is preferable, and among them, low-density polyethylene, linear low-density polyethylene (linear low-density polyethylene), and ethylene-α-olefin copolymer are preferable.

The density of the low density polyethylene is preferably 0.90~0.93g / cm ^3, more preferably 0.91~0.92g / cm ^3. The weight average molecular weight of the low density polyethylene is not particularly limited, but is preferably 30,000 to 200,000, more preferably 50,000 to 60,000. The MFR at 190 ° C. of the low density polyethylene is not particularly limited, but is preferably 1.0 to 5.0 (g / 10 minutes), more preferably 2.0 to 4.0 (g / 10 minutes). It is. In addition, the density in this specification shall mean the density obtained based on JISK6922-2 and JISK7112. Moreover, MFR in this invention can be measured based on ISO1133 (JISK7210). Moreover, the weight average molecular weight in this specification can be measured by GPC (gel permeation chromatography) method. Especially, it is preferable to measure by the high temperature GPC method (high temperature GPC apparatus). Specifically, for example, a high temperature GPC method described in JP-A-2009-184705 can be used.

  The linear low density polyethylene is a straight chain having a short chain branch (the branch length is preferably 1 to 6 carbon atoms) obtained by polymerizing ethylene and an α-olefin having 4 to 8 carbon atoms. Polyethylene. As the α-olefin used for the linear low density polyethylene, 1-butene, 1-octene, 1-hexene and 4-methylpentene-1 are preferable. In the above-mentioned linear low density polyethylene, the content (content ratio) of the ethylene monomer repeating unit (repeating unit derived from ethylene monomer) with respect to the repeating unit of all constituting monomers (repeating unit derived from all constituent monomers) is 90. More than mol% is preferable. As the linear low-density polyethylene, a so-called metallocene linear low-density polyethylene (metallocene LLDPE) prepared using a metallocene catalyst is particularly preferable from the viewpoint of improving low-temperature heat sealability.

The density of the linear low-density polyethylene is preferably 0.90~0.93g / cm ^3, more preferably 0.91~0.92g / cm ^3. The weight average molecular weight of the linear low density polyethylene is not particularly limited, but is preferably 30,000 to 200,000, more preferably 50,000 to 100,000, and still more preferably 50,000 to 60,000. The MFR at 190 ° C. of the linear low density polyethylene is not particularly limited, but is preferably 1.0 to 5.0 (g / 10 minutes), more preferably 2.0 to 4.0 (g / 10 minutes).

  The ethylene-α-olefin copolymer is a copolymer of ethylene and α-olefin. The α-olefin is not particularly limited as long as it is an α-olefin other than ethylene. For example, propylene, butene-1, pentene-1, hexene-1, 4-methyl-pentene-1, heptene-1, octene C3-C8 alpha olefins, such as -1. Among these, an ethylene-α-olefin copolymer elastomer using butene-1 is preferable. In the ethylene-α-olefin copolymer, the content of the ethylene monomer repeating units relative to the repeating units of all the constituent monomers is preferably 60 to 95 mol%, more preferably 80 to 90 mol%. The ethylene-α-olefin copolymer plays a role of further improving the heat sealability of the porous film.

The density of the ethylene-α-olefin copolymer is preferably less than 0.90 g / cm ³ , more preferably 0.86 to 0.89 g / cm ³ , and still more preferably 0.87 to 0.89 g / cm ^3. It is. The weight average molecular weight of the ethylene-α-olefin copolymer is not particularly limited, but is preferably 50,000 to 200,000, more preferably 80,000 to 150,000. The MFR at 190 ° C. of the ethylene-α-olefin copolymer is not particularly limited, but is preferably 1.0 to 5.0 (g / 10 min), more preferably 2.0 to 4.0 (g / 10 minutes).

  The porous film is not particularly limited, but preferably contains an inorganic filler (inorganic filler). The inorganic filler plays a role of making the film porous by generating voids (pores) around the filler by stretching. Examples of the inorganic filler include, for example, talc, silica, stone powder, zeolite, alumina, aluminum powder, iron powder, and carbonate metal salts such as calcium carbonate, magnesium carbonate, magnesium carbonate-calcium, and barium carbonate; magnesium sulfate, Metal salts of sulfuric acid such as barium sulfate; metal oxides such as zinc oxide, titanium oxide and magnesium oxide; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide and barium hydroxide; oxidation Examples thereof include metal hydrates (hydrated metal compounds) such as magnesium-nickel oxide hydrate and magnesium oxide-zinc oxide hydrate. Of these, calcium carbonate and barium sulfate are preferable. The shape of the inorganic filler is not particularly limited, and a flat plate shape, a granular shape, and the like can be used. From the viewpoint of forming a void (hole) by stretching, a granular shape (particle shape) is preferable. As the inorganic filler, inorganic particles (inorganic fine particles) made of calcium carbonate are particularly preferable.

  Although the particle diameter (average particle diameter) of the said inorganic filler (inorganic particle) is not specifically limited, For example, 0.1-10.0 micrometers is preferable, More preferably, it is 0.5-5.0 micrometers. When the particle size of the inorganic filler is 0.1 μm or more, the void formability is improved, and by setting the particle size to 10.0 μm or less, film formation (film formation) is broken and appearance defects can be suppressed, which is preferable.

  Although content of the said inorganic filler (inorganic particle) in a porous film is not specifically limited, For example, it is 50-150 weight part with respect to all the polymer components (100 weight part) which comprise a porous film. It is preferably 80 to 120 parts by weight. When the content of the inorganic filler is 50 parts by weight or more, the void formability is improved, and by setting the content to 150 parts by weight or less, the film formation is broken and appearance defects can be suppressed, which is preferable.

  In the porous film, various additives such as a colorant, an antioxidant, an antioxidant, an ultraviolet absorber, a flame retardant, and a stabilizer are further blended within a range that does not impair the effects of the present invention. Also good.

  The porous film can be produced by a melt film formation method (T-die method, inflation method). Of these, the T-die method is preferable. For example, the above polyolefin resin, inorganic filler, and, if necessary, various additives are mixed and dispersed by biaxial kneading extrusion, once pelletized, and then melt extruded by a single screw extruder. An unstretched film is produced, and the unstretched film is made porous by stretching (for example, stretching uniaxially or biaxially). When a porous film is used as a laminated film, a coextrusion method can be preferably used. The porous film may be subjected to various treatments such as back treatment and antistatic treatment as necessary.

  In the production of the porous film, the extrusion temperature is preferably 170 to 270 ° C, more preferably 180 to 260 ° C, still more preferably 230 to 250 ° C. Moreover, 5-25 m / min is preferable for the taking-up speed at the time of unstretched film preparation, and 5-40 degreeC is preferable for take-off roll temperature (cooling temperature), More preferably, it is 20-30 degreeC.

  As a method for stretching the above-mentioned unstretched film [uniaxial stretching, biaxial stretching (sequential biaxial stretching, simultaneous biaxial stretching), etc.], a known and conventional stretching method such as a roll stretching method or a tenter stretching method can be used. . The stretching temperature is preferably 50 to 100 ° C, more preferably 60 to 90 ° C. From the viewpoint of making it porous and forming a stable film, the draw ratio (uniaxial direction) is preferably 2 to 5 times, more preferably 3 to 4 times. In the case of biaxial stretching, the area stretch ratio is preferably 2 to 10 times, more preferably 3 to 7 times.

  The thickness of the porous film is preferably 20 to 200 μm, more preferably 50 to 150 μm, and still more preferably 50 to 120 μm. It is preferable that the thickness is 20 μm or more because the occurrence of edge breakage [a phenomenon in which a film tears at the boundary between a heat-sealed portion and a non-heat-sealed portion] when producing a disposable body warmer can be suppressed. Moreover, it is preferable for the thickness to be 200 μm or less because the sealing performance when producing a disposable body warmer is improved and the occurrence of sealing failure can be suppressed.

  The air permeability resistance of the porous film is preferably 1000 to 80,000 seconds / 100 cc, more preferably 5000 to 50,000 seconds / 100 cc, from the viewpoint of air permeability. The air resistance can be determined by the Oken tester method in accordance with JIS P 8117.

(Adhesive layer)
In the bag-constituting member (b), the method of combining (laminating) the nonwoven fabric (a) and the porous film is not particularly limited, but a method of bonding through an adhesive layer is preferable. The said adhesive bond layer is not specifically limited, The well-known adhesive bond layer used for bonding of a nonwoven fabric and a porous film etc. can be used. The “adhesive” forming the adhesive layer includes the meaning of “pressure-sensitive adhesive (pressure-sensitive adhesive)”.

  Although it does not specifically limit as an adhesive agent which forms the said adhesive bond layer, For example, rubber type (natural rubber, a styrene-type elastomer, etc.), urethane type (acryl urethane type), polyolefin type (ethylene-vinyl acetate copolymer ( EVA), ethylene-methyl acrylate copolymer (EMA), etc.), known adhesives such as acrylic, silicone, polyester, polyamide, epoxy, vinyl alkyl ether, and fluorine. Moreover, the said adhesive agent can be used individually or in combination of 2 or more types. Among these, polyamide adhesives and polyester adhesives are particularly preferable.

  In addition, the adhesive may be an adhesive having any form and is not particularly limited, but can be applied by melting with heat without using a solvent, However, it has the advantage that it can be applied directly to form an adhesive layer, and the heat seal part has the advantage that a greater adhesive force can be obtained by heat seal processing. preferable. That is, the above-mentioned adhesive is preferably a polyamide-based or polyester-based hot melt adhesive, and more preferably a thermoplastic polyamide-based hot melt adhesive or a thermoplastic polyester-based hot melt adhesive.

The specific method for laminating the nonwoven fabric (a) and the porous film varies depending on the type of the adhesive and is not particularly limited. However, when a hot-melt adhesive is used, the adhesive is nonwoven fabric (a). A method in which a porous film is pasted after coating (coating) on top is preferred. As the coating method, a publicly known and commonly used method used as a hot melt adhesive coating method can be used, and is not particularly limited. For example, from the viewpoint of air permeability, coating by spray coating, stripe coating Dot coating is preferred. The coating amount (solid content) of the adhesive is not particularly limited, but is preferably 0.5 to 20 g / m ² , more preferably 1 to 10 g / m ² from the viewpoints of coating property, adhesiveness, economy, and the like. More preferably, it is 3 to 5 g / m ² .

  Among the above, a porous adhesive layer is particularly preferable as the adhesive layer. That is, the bag-constituting member (b) is a laminate in which a nonwoven fabric (a) and a porous film are bonded together via a porous adhesive layer (adhesive layer formed by fiberizing an adhesive) ( A composite member) is preferable. The porous adhesive layer is an adhesive layer formed by fiberizing an adhesive. Preferably, it is an adhesive layer formed by fiberizing a hot melt type (hot melt type) adhesive by a spray method (spray coating), and more preferably, the adhesive is heated and melted by a curtain spray method. It is the adhesive bond layer formed by the method of spraying through hot air and making it fiber-ized. The adhesive layer is a porous adhesive layer formed by fiberizing (particularly, by being an adhesive layer formed by applying a spray method), so that the bag component (b) There is an advantage that the air permeability is not lowered.

[Other bag components]
The other bag-constituting members [the bag-constituting members other than the bag-constituting member (b) constituting the disposable body warmer (inner bag) of the present invention] are not particularly limited, and are known and commonly used. Can be used. For example, in the case of a warmer that is not attached, a laminate of a nonwoven fabric and a porous film, a plastic film, and the like can be given. Moreover, in the case of the warmer to stick, the bag structural member which has an adhesive layer is preferable, for example, the bag structural member which consists of a base material and an adhesive layer is mentioned, "Nitotac" (Nitto Lifetech Co., Ltd.) ( A heat-sealable polyolefin base material and a SIS pressure-sensitive adhesive layer laminated body) are available as commercial products.

  The substrate is preferably composed of, for example, a heat seal layer, a fiber layer (for example, a nonwoven fabric layer), a film layer, or the like. More specifically, as a base material, a heat seal layer (including a heat sealable film layer) alone, a laminate of a heat seal layer and a fiber layer, a heat seal layer and a film layer without heat sealability A laminated body etc. are mentioned.

As a nonwoven fabric used for the said nonwoven fabric layer, well-known and usual nonwoven fabrics, such as a nonwoven fabric made from nylon, a nonwoven fabric made from polyester, a nonwoven fabric made from polyolefin, a nonwoven fabric made from rayon, etc. (The nonwoven fabric by a natural fiber, the nonwoven fabric by a synthetic fiber, etc.) are mentioned, for example. Moreover, the manufacturing method of the said nonwoven fabric is not specifically limited, For example, the spun bond method, the spun lace method, the needle punch method, the chemical bond method, the thermal bond method, the stitch bond method, the melt blow method etc. are mentioned. Furthermore, the nonwoven fabric may be in any form of a single layer or multiple layers. The said nonwoven fabric may be comprised only from 1 type of fiber, and may be comprised combining multiple types of fiber. Although the fabric weight of the said nonwoven fabric is not specifically limited, From a viewpoint of workability or cost, 20-150 g / m < ² > is preferable. Moreover, the fiber diameter, fiber length, etc. of the said nonwoven fabric are not specifically limited.

  The heat seal layer is formed from a heat sealable resin (heat sealable resin) or a heat sealable resin composition containing a heat sealable resin. The heat-sealable resin is not particularly limited, but a polyolefin resin (olefin resin) is preferable. As said polyolefin resin, at least olefin component (alpha-olefins, such as ethylene, propylene, butene-1, pentene-1, hexene-1, 4-methyl-pentene-1, heptene-1, octene-1, etc.). If it is resin made into a monomer component, it will not specifically limit. Specifically, for example, polyethylene resin (low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-α-olefin copolymer, etc.), polypropylene resin (polypropylene, propylene-α, etc.) -Olefin copolymer), polybutene resin (polybutene-1, etc.), poly-4-methylpentene-1, and the like. Examples of polyolefin resins include ethylene-unsaturated carboxylic acid copolymers such as ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers; ionomers; ethylene-methyl acrylate copolymers, ethylene- Ethylene- (meth) acrylic ester copolymers such as ethyl acrylate copolymer and ethylene-methyl methacrylate copolymer; ethylene-vinyl acetate copolymer; ethylene-vinyl alcohol copolymer can also be used. . Among these, polyethylene resins are preferable, and low density polyethylene, linear low density polyethylene, and ethylene-α-olefin copolymers are more preferable. The heat-sealable resins can be used alone or in combination of two or more. The heat seal layer may have either a single layer or a multiple layer form.

  Among these, as the heat-sealable resin composition, a polyolefin-based resin composition containing at least an ethylene-α-olefin copolymer is preferable, and in particular, low-density polyethylene and / or linear low-density polyethylene, ethylene- A polyolefin resin composition containing an α-olefin copolymer is preferred. In the polyolefin resin composition, the content of the ethylene-α-olefin copolymer is not particularly limited, but is preferably 5% by weight or more, more preferably 10%, based on the total weight (100% by weight) of the polyolefin resin. -50% by weight, more preferably 15-40% by weight. Furthermore, from the viewpoint of improving low-temperature heat sealability, the linear low-density polyethylene is preferably a linear low-density polyethylene prepared using a metallocene catalyst.

  A well-known and usual film can be used for the said film layer. Examples of the resin forming the film layer include polyester resins and polyolefin resins. Of these, polyolefin resins are preferred from the viewpoints of price and flexibility. As polyolefin resin, the resin similar to resin illustrated in the heat seal layer, etc. can be used. The film layer may be a single layer film or a laminated film having two or more layers. Further, the film may be a non-oriented film or a film stretched and oriented in a uniaxial or biaxial direction, but is preferably a non-oriented film.

  Although the thickness of the said base material is not specifically limited, 10-500 micrometers is preferable, More preferably, it is 12-200 micrometers, More preferably, it is 15-100 micrometers. The base material may be subjected to various treatments such as back treatment and antistatic treatment as necessary.

  The pressure-sensitive adhesive layer plays a role of sticking a disposable body warmer (inner bag) to an adherend during use. The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is not particularly limited. For example, a rubber-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive (acrylic urethane-based pressure-sensitive adhesive), an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, and a polyamide. Known pressure-sensitive adhesives such as a pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, a vinyl alkyl ether-based pressure-sensitive adhesive, and a fluorine-based pressure-sensitive adhesive. Of these, rubber adhesives and urethane (acrylic urethane) adhesives are particularly preferable. The pressure-sensitive adhesives can be used alone or in combination of two or more.

  Examples of the rubber-based pressure-sensitive adhesive include rubber-based pressure-sensitive adhesives using natural rubber and various synthetic rubbers as a base polymer. Examples of rubber adhesives based on synthetic rubber include styrene / butadiene (SB) rubber, styrene / isoprene (SI) rubber, styrene / isoprene / styrene block copolymer (SIS) rubber, styrene / butadiene / Styrene block copolymer (SBS) rubber, styrene / ethylene / butylene / styrene block copolymer (SEBS) rubber, styrene / ethylene / propylene / styrene block copolymer (SEPS) rubber, styrene / isoprene / propylene / styrene block Copolymer (SIPS) rubber, styrene rubber such as styrene / ethylene / propylene block copolymer (SEP) rubber (also referred to as “styrene elastomer”), polyisoprene rubber, recycled rubber, butyl rubber, polyisobutylene, etc. of Such as gender body and the like. Among them, a styrene elastomer adhesive is preferable, and a SIS adhesive and an SBS adhesive are more preferable. The pressure-sensitive adhesives can be used alone or in combination of two or more.

  As the urethane pressure-sensitive adhesive, a known and commonly used urethane pressure-sensitive adhesive can be used, and is not particularly limited. For example, the urethane type illustrated in Japanese Patent No. 3860880 and Japanese Patent Application Laid-Open No. 2006-288690. An adhesive or the like is preferable. Among these, an acrylic urethane pressure-sensitive adhesive composed of isocyanate / polyester polyol is preferable. Moreover, it is preferable that the said acrylic urethane type adhesive is a foaming type adhesive which has a bubble from a viewpoint of reducing the irritation | stimulation to the skin at the time of sticking directly on skin. Such a foaming type pressure-sensitive adhesive can be produced by, for example, a method of adding a known and usual foaming agent to the pressure-sensitive adhesive.

  The pressure-sensitive adhesive may be any pressure-sensitive adhesive, such as an emulsion-type pressure-sensitive adhesive, a solvent-type pressure-sensitive adhesive, and a hot-melt-type pressure-sensitive adhesive (hot-melt-type pressure-sensitive adhesive). It is done. Of the above, a hot-melt pressure-sensitive adhesive (hot-melt pressure-sensitive adhesive) is particularly preferable because it can be directly applied without using a solvent to form a pressure-sensitive adhesive layer.

  The pressure-sensitive adhesive may be a pressure-sensitive adhesive having any of the characteristics, for example, a pressure-sensitive adhesive (thermosetting pressure-sensitive adhesive) which is cured by crosslinking or the like caused by heating. ), And a pressure-sensitive adhesive having active energy ray curability that cures by crosslinking or the like caused by irradiation with active energy rays (active energy ray-curable pressure-sensitive adhesive). Among these, an active energy ray-curable pressure-sensitive adhesive is suitable because it is solvent-free and does not excessively impregnate non-woven fabrics or porous substrates. For the thermosetting pressure-sensitive adhesive, a crosslinking agent, a polymerization initiator, or the like for exhibiting thermosetting properties is appropriately used. For the active energy ray-curable pressure-sensitive adhesive, a cross-linking agent or a photopolymerization initiator for exhibiting active energy ray curability is appropriately used.

  The pressure-sensitive adhesive layer may be protected by a known or commonly used release film (separator) until use.

[Heating element]
The heating element in the disposable warmer of the present invention can be a heating element used in conventional disposable warmers, and is not particularly limited. For example, metal powder such as iron powder, activated carbon, water, water retention agent (wood powder) , Vermiculite, diatomaceous earth, perlite, silica gel, alumina, water-absorbing resin, etc.), sodium chloride, and the like can be used.

[Disposable body warmer]
The disposable body warmer of this invention has the said bag body structural member (b) as an essential structural member. Especially, it has a structure where the heat generating body was enclosed in the inside of the bag formed by heat-sealing (for example, four-way heat-sealing) the 2 or more bag body structural members containing a bag body structural member (b). As the bag body, for example, in the case of a body warmer, a bag body [bag body] comprising a bag body constituent member (b) and a bag body constituent member (adhesive sheet for body warmers) composed of a base material and an adhesive layer. The surface on the porous film side of the structural member (b) and the surface on the substrate side of the adhesive sheet for warmers are heat-sealed. Further, in the case of a body warmer that is not attached, a bag comprising the bag-constituting member (b) and the bag-constituting member (b) [the surfaces on the porous film side of the bag-constituting member (b) are heat sealed Or a bag body comprising a bag member (b) and another bag member which is a composite member of a porous film and a nonwoven fabric [the surface of the bag member (b) on the porous film side] The surface of the other bag-constituting member on the porous film side is heat-sealed].

  In the bag member (b), the surface on the porous film side is preferably used as a heat seal surface. That is, it is preferable that the bag member (b) is heat-sealed so that the surface on the porous film side is in contact with the other bag member. Moreover, in the body warmer to stick, it is preferable that a bag body structural member (b) is used as a member (what is called a surface material) on the opposite side to the side which contacts a to-be-adhered body from a viewpoint of the oxygen supply property to a heat generating body.

  FIG. 1 is a schematic view (cut section end view) showing an example of a disposable hand warmer (sticking hand warmer) of the present invention. The disposable body warmer of the present invention shown in FIG. 1 has a bag member (b) 14 and other bag members 17 (consisting of a base material 15 and an adhesive layer 16), and an end (heat seal portion 19). The bag body is formed by heat-sealing, and the heating element 18 is enclosed inside. The bag constituting member (b) 14 is a composite member of the nonwoven fabric (a) 11 and the porous film 12. The nonwoven fabric (a) 11 and the porous film 12 are bonded together via an adhesive layer 13.

The method (apparatus) for heat sealing when forming the disposable body warmer of the present invention (when forming the bag) is not particularly limited, but pressure bonding with a heat sealer is preferable. Further, from the viewpoint of sealing strength, the heat seal temperature at that time is preferably 90 to 200 ° C, more preferably 150 to 200 ° C. Heat sealing pressure is, in view of seal strength is preferably 0.5~20kgf / cm ^2, more preferably 2.0~20kgf / cm ^2. Moreover, 0.001-1.0 second is preferable and, as for heat seal time, More preferably, it is 0.001-0.5 second.

  The size of the disposable body warmer (inner bag) of the present invention is not particularly limited. For example, 100 mm (MD direction) × 80 mm (TD direction), 130 mm (MD direction) × 95 mm (TD direction), 130 mm (MD direction) A size such as × 100 mm (TD direction) can be mentioned. Among them, a disposable body warmer having a length in the MD direction of 125 mm or more and a length in the TD direction of 90 mm or more is preferable from the viewpoint that the effect of warming quickly in the present invention can be more effectively realized.

  The disposable body warmer (inner bag) in the present invention is stored in the outer bag and sold as a warmer product. The base material constituting the outer bag is not particularly limited. For example, a plastic base material, a fiber base material (nonwoven fabric base material or woven base material made of various fibers), metal base material (various types) And a metal foil base material by a metal component). Among these, a plastic base material is preferable. Examples of the plastic base material include polyolefin base materials (polypropylene base materials, polyethylene base materials, etc.), polyester base materials (polyethylene terephthalate base materials, etc.), and styrene base materials (polystyrene base materials). In addition, styrene copolymer-based substrates such as acrylonitrile-butadiene-styrene copolymer-based substrates), amide resin-based substrates, acrylic resin-based substrates, and the like. The base material constituting the outer bag may be a single layer or a laminate. The thickness of an outer bag is not specifically limited, For example, 30-300 micrometers is preferable.

  Moreover, it is preferable that the said outer bag has a layer (gas barrier property layer) which has the characteristic (gas barrier property) which prevents permeation | transmission of gas components, such as oxygen and water vapor | steam. Although it does not specifically limit as a gas barrier layer, For example, an oxygen barrier resin layer (For example, a polyvinylidene chloride resin, an ethylene-vinyl alcohol copolymer, polyvinyl alcohol, a polyamide resin), a water vapor barrier resin layer (For example, a polyolefin resin, a polyvinylidene chloride resin), an oxygen barrier property or a water vapor barrier inorganic compound layer (for example, a metal simple substance such as aluminum, a metal oxide such as a metal oxide such as silicon oxide or aluminum oxide) Etc.). The gas barrier layer may be a single layer (a base material constituting the outer bag itself) or a laminate.

  The outer bag may be a bag of any form or structure, for example, a so-called “4-side bag”, a so-called “3-side bag”, a so-called “pillow bag”, a so-called “self-supporting bag” (so-called “ Standing pouches)), so-called “gazette bags” and other forms of bags. Among these, a four-sided bag is particularly preferable. The outer bag may be produced using an adhesive, but is preferably produced by heat sealing (thermal fusion) such as a four-way heat sealing bag.

  The disposable warmer of the present invention may be a type of warmer (a warmer) that is attached to an adherend (clothing or skin), or may be a type of warmer that is not attached (a warmer that is not attached). Of these, the warmer is preferred.

The disposable body warmer of the present invention has a bag body constituent member (b) containing a nonwoven fabric (a) having a relatively small basis weight (average basis weight) and a relatively large variation in micro basis weight (b). The material is used for bags. Since the disposable body warmer using such a bag constituent member (ventilating material) has a portion with a high airflow rate locally in the plane of the venting material, the oxygen (air) airflow rate is very small. The rise time is shorter than a disposable body warmer using a ventilation material using a non-woven fabric with small variations. For this reason, the disposable body warmer of the present invention using the bag-constituting member (b) warms faster with a shorter rise time than the conventional body warmer. In the case of a ventilation material using a nonwoven fabric with small variation in micro basis weight, in order to shorten the rise time sufficiently, it is necessary to make the basis weight of the nonwoven fabric extremely small, and the strength of the ventilation material is excessively lowered. Absent.
Moreover, since the fabric weight (average fabric weight) of a nonwoven fabric (a) is comparatively small, the disposable warmer of this invention has high body temperature and can feel warmer.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
(Porous film)
100 parts by weight of linear low density polyethylene (LLDPE) (weight average molecular weight (Mw): 60,000), 20 parts by weight of ethylene-α-olefin copolymer (copolymer of ethylene and butene-1) and polyethylene (Mw) : 400,000) 20 parts by weight of a polymer component, 150 parts by weight of calcium carbonate (particles) having an average particle size of 1.1 μm and 1 part by weight of an antioxidant were melt-kneaded at 180 ° C. to obtain a mixed material. Obtained.
Using the above mixed material, melt extrusion was performed by a T-die method to produce an unstretched film. Next, the unstretched film was stretched in the longitudinal (MD) direction at a stretching temperature of 100 ° C. and a stretch ratio of 4.0 times by a uniaxial roll stretching method to obtain a polyethylene-based porous film having a thickness of 70 μm.
(adhesive)
As the adhesive, a hot-melt type thermoplastic copolymer polyamide adhesive was used.
(Nonwoven fabric)
A polyester spunbonded nonwoven fabric (product name “ELTAS E01020” manufactured by Asahi Kasei Fibers Co., Ltd.) was used.

(Breathable bag component)
The above-mentioned nonwoven fabric is coated with the adhesive (polyamide-based hot melt adhesive) by spray coating (spray coating) (coating amount: 5.0 g / m ² ), and the nonwoven fabric is coated with the adhesive. The surface and the porous film obtained above were bonded together to produce a bag constituting member (breathable bag constituting member).
That is, the said bag body structural member is a nonwoven fabric and a porous film bonded together through a porous adhesive layer.

(Disposable body warmer)
Furthermore, a disposable body warmer was produced.
Each of the air-permeable bag constituting member obtained above and the adhesive sheet for warmers (manufactured by Nitto Lifetech Co., Ltd., trade name “Nitotack E12”) is 130 mm (MD direction: longitudinal direction) × 95 mm (CD direction). : In the width direction).
Next, the breathable bag constituting member and the warming pressure sensitive adhesive sheet are divided into the porous film surface of the breathable bag constituting member and the base film surface of the warming pressure sensitive adhesive sheet (the surface opposite to the pressure sensitive adhesive layer). ) Are placed so as to face each other and heat-sealed in three directions (two locations in the MD direction and one location in the CD direction), and then a heating element was introduced into the inside through the opening. As the heating element, a commercially available warmer heating element (material: iron powder, water, activated carbon, vermiculite, water-absorbing resin, salt, weight: 35.0 g) was used.
Finally, the remaining one (one in the CD direction) was heat sealed to obtain a disposable body warmer (inner bag).
The heat sealing was performed using a stepping type sealer “FUJI IMPULSE sealer” manufactured by Fuji Impulse Co., Ltd. under the conditions of a temperature of 180 ° C. and a heating time of 0.4 seconds. The heat seal width was 5.0 mm. Heat sealing was performed at the end.
The dimensions of the obtained disposable body warmer (inner bag) are shown in FIG. In FIG. 3, 31 is a disposable body warmer (inner bag), 32 is a heat seal portion, and 33 is a non-heat seal portion.

(Disposable body warmer with outer bag)
Next, the disposable body warmer (inner bag) obtained above is housed in a commercially available outer bag (length 165 mm × width 120 mm × thickness 0.075 mm, material: polypropylene (PP)) and heat-sealed. A disposable body warmer (a warmer product) in an outer bag was obtained.

Example 2
A non-woven spunbond nonwoven fabric (product name “ELTAS N03025” manufactured by Asahi Kasei Fibers Co., Ltd.) was used as the nonwoven fabric in the same manner as in Example 1 to obtain a disposable body warmer containing a outer bag (a body product). .

Comparative Example 1
The outer bag was the same as in Example 1 except that a polypropylene SMMS (spunbond-meltblown-meltblown-spunbond) non-woven fabric (Asahi Kasei Fibers Co., Ltd., trade name "ELTASGARD PMA020") was used. A disposable disposable warmer (a warmer product) was obtained.

Comparative Example 2
The nonwoven fabric surface of polyester spunbonded nonwoven fabric (Asahi Kasei Fibers Co., Ltd., trade name “ELTAS E01040”) was rubbed with a rubber glove to loosen the fibers, thereby obtaining a nonwoven fabric with large variation in fine weight per unit area.
Except for using the non-woven fabric obtained above as a non-woven fabric, a disposable body warmer (Cairo product) containing an outer bag was obtained in the same manner as in Example 1.

Comparative Example 3
A disposable body warmer with an outer bag (a body warmer product) was obtained in the same manner as in Example 1 except that a polyester spunbonded nonwoven fabric (trade name “ELTAS E01040” manufactured by Asahi Kasei Fibers Co., Ltd.) was used as the nonwoven fabric. .

(Evaluation)
The following evaluation was performed about the disposable body warmers (disposable body warmers with an outer bag) produced in the examples and comparative examples. The evaluation results are shown in Table 1.

(1) Unevenness of nonwoven fabric and variation in fine basis weight From the disposable body warmers (inner bags) (non-heat-sealed portions) obtained in the examples and comparative examples, as shown in FIG. Twelve pieces of a square bag member (a bonded body of a nonwoven fabric and a porous film) were cut out.
Subsequently, the said fragment | piece was immersed in isopropyl alcohol (IPA) for 1 minute, the nonwoven fabric and the porous film were isolate | separated by hand, and the adhesive agent was removed from the nonwoven fabric. Furthermore, the separated nonwoven fabric was left for 30 minutes and dried naturally. In this way, 12 samples for measurement (nonwoven fabric: length 25 mm × width 25 mm) were collected.
The weight of the measurement sample was measured, the weight per unit area (unit: g / m ² ) was calculated, and this was used as the minute basis weight of the measurement sample. [Fine weight of measurement sample (unit: g / m ² ) = weight of measurement sample (unit: g) / surface area of measurement sample (0.000625 m ² )]
Furthermore, the standard deviation (σ) and the average value (AVE) of the micro-meshing of the 12 measurement samples were calculated, and the “micro-meshing variation” of the nonwoven fabric was calculated according to the following formula.
Variation in minute weight (%) = (3σ / AVE) × 100
Further, the average value (AVE) of the above-mentioned minute basis weight was defined as “weight per unit area” of the nonwoven fabric.
In addition, FIG. 4 is explanatory drawing which shows typically the sampling method (collection method of the fragment | piece of the bag body structural member from a disposable body warmer) in the measuring method of the fabric weight of said nonwoven fabric, and the variation | variation in micro fabric weight (The collection method of the fragment of a bag body structural member from a disposable body warmer) It is the schematic plan view seen from the air-permeable bag body structural member side. 4, 41 is a disposable body warmer (inner bag), 42 is a heat seal portion, 43 is a non-heat seal portion, and 44 is a piece (one piece) of a bag member.

(2) Rise time of disposable warmers (conforms to JIS S 4100)
Based on JIS S 4100 (in the case of “Haru type”), a “rise time” (a time required to raise the temperature from 40 ° C. immediately after the start of heat generation) was obtained.

  As can be seen from the evaluation results (Table 1), the disposable warmers of the present invention (Examples) were excellent disposable warmers that had a short rise time and warmed faster. A disposable body warmer (comparative example) using a non-woven fabric having a large basis weight or a non-woven fabric having a small basis weight as a non-woven fabric of a breathable bag member has a long rise time.

11 Nonwoven fabric (a)
12 Porous film 13 Adhesive layer 14 Bag body component (b)
DESCRIPTION OF SYMBOLS 15 Base material 16 Adhesive layer 17 Other bag body structural member 18 Heat generating body 19 Heat seal part 21 Disposable body warmer (inner bag)
22 Heat seal part 23 Non heat seal part 24 Sample for measurement 31 Disposable body warmer (inner bag)
32 Heat seal part 33 Non heat seal part 41 Disposable body warmer (inner bag)
42 Heat-sealed portion 43 Non-heat-sealed portion 44 Fragment of bag-forming member

Claims (1)

Disposable body warmer which basis weight is characterized by having a bag member comprising a single layer nonwoven fabric and the porous film is 8 to 15 percent variation in it and following small basis weight is between 12 and 25 g / m ^2.
Fine weight variation: 6 to 12 square measurement samples having a length of 25 mm and a width of 25 mm are taken from the nonwoven fabric, the weight is measured, and the standard deviation (σ) and the average value (AVE) of the weight are calculated. A ratio (percentage:%) [(3σ / AVE) × 100] of a value obtained by multiplying the standard deviation with respect to the average value by 3 is defined as a variation in minute weight.

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