JP2015093414A - Air-permeable laminate, and disposable body warmer obtained by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air-permeable laminate which has excellent heat sealability, which exhibits excellent product characteristics such as exothermic maximum temperature and exothermic duration when used in a disposable body warmer, and which comprises a nonwoven fabric and a porous film.SOLUTION: The air-permeable laminate having 5,000-100,000 seconds/100 cc Oken type air permeability is obtained by sticking a thermoplastic long-fiber nonwoven fabric to the porous film. The thermoplastic long-fiber nonwoven fabric has 5-25% partial thermal press-fixing rate and 15-50 g/mbasis weight. The porous film: contains 40-62 wt.% straight-chain low-density polyethylene, 2-10 wt.% low-density polyethylene and 35-50 wt.% inorganic filler as constituent components; has 40-100 g/mbasis weight; has pores having 1 μm or smaller median diameter and 0.3 ml/g or larger pore volume when measured by a mercury penetration method; and exhibits 5 N/10 mm or stronger stress when extended by 10%.

Description

  The present invention relates to a breathable laminate and a disposable body warmer using the same. More specifically, by using a porous film in which the constituent components are well kneaded and dispersed, the breathable laminate in which the distribution of fine pores is made uniform and the breathability and moisture permeability are controlled, and the disposable body warmer using the same About.

  At present, as a member (bag body constituting member) constituting a storage bag (bag body) enclosing a heating element of a warmer (disposable body warmer, etc.), a porous film and a breathable base material such as a nonwoven fabric are bonded. Breathable materials (breathing materials) are known. For example, the following Patent Document 1 discloses a breathable and moisture-permeable laminate in which a reinforcing material is laminated on one side of a uniaxially stretched porous film, and the following Patent Document 2 discloses an A having a difference in melting point. A bag-constituting member composed of a two-layer porous film consisting of a layer B and a B-layer is disclosed, and the following Patent Document 3 discloses breathability by changing the amount of adhesive applied when bonding a nonwoven fabric and a porous film. A layered body for warmers is disclosed, and the following patent document 4 is made of a breathable material in which a polyester non-woven fabric is laminated on a porous film, and is not easily deformed and does not feel strange when used. It is disclosed.

  These warmers require a bag that has a uniform distribution of pores in a porous film having fine ventilation holes and that has no problems with the characteristics of disposable warmers such as the maximum temperature when heat is generated and the duration of heat generation. Has been.

Japanese Patent Publication No. 6-22959 JP 2011-104993 A Japanese Patent No. 3497634 Japanese Patent No. 48339401

  The object of the present invention is that when used for a bag component of a disposable body warmer, the heat sealability is good, the product characteristics of the disposable body warmer such as the maximum heat generation temperature and the heat generation duration are excellent, and the edge breaks during heat sealing, etc. It is an object to provide a breathable laminate of a nonwoven fabric and a porous film that has little productivity and excellent productivity.

  As a result of intensive investigations, the inventors have found that film forming workability is improved by blending resins with different densities and viscosities, and kneading and melting the resin with a specific kneading machine, and stretching unevenness. Therefore, a porous film having a specific pore diameter and pore volume, small variation in air permeability in the width and length directions, and excellent heat sealability can be obtained. It was found that the above object was achieved by using this porous film, and the present invention was completed.

That is, the present invention is as follows.
(1) A breathable laminate in which a nonwoven fabric and a porous film are joined, wherein the nonwoven fabric comprises a partial thermocompression bonding rate of 5 to 25% and a basis weight of 15 to 50 g / m ² plastic long fiber nonwoven fabric, The porous film contains 40 to 62 wt% of linear low density polyethylene, 2 to 10 wt% of low density polyethylene and 35 to 50 wt% of inorganic filler as constituent components, and has a basis weight of 40 to 100 g / m ^2. A porous film having a median diameter and pore volume of 1 μm or less and 0.3 ml / g or more by mercury intrusion method, and a stress at 10% elongation of 5 N / 10 mm or more, respectively. Breathable laminate characterized by ˜100,000 seconds / 100 cc.
(2) The breathable laminate according to (1), wherein the inorganic filler is calcium carbonate having a 50% average particle diameter of 1 to 10 μm.
(3) The breathable laminate according to (1) or (2), wherein the thermoplastic long-fiber nonwoven fabric comprises at least one selected from polyester fibers, polyamide fibers, and polyolefin fibers. .
(4) The breathable laminate according to any one of (1) to (3), wherein the porous film has a draw ratio of 3 to 5 times.
(5) The breathable laminate according to any one of (1) to (4), wherein the bonding is partial bonding, and a non-bonding area ratio is 15 to 55%.
(6) A disposable body warmer using the breathable laminated body according to any one of (1) to (5) as a bag constituting member.
(7) Partially thermocompression-bonded thermoplastic long-fiber nonwoven fabric having a basis weight of 15 to 50 g / m ² obtained by melt spinning a thermoplastic resin by a spunbond method, and 40 to 40 of linear low-density polyethylene as a constituent component A mixed resin containing 62 wt%, low density polyethylene 2 to 10 wt% and inorganic filler 35 to 50 wt% was mixed and dispersed by a twin screw kneading extruder, and then a T die was added by a twin screw kneading extruder with a gear pump. An unstretched film melt-formed using a method is stretched 3 to 5 times uniaxially at a stretching temperature of 40 to 100 ° C., and then heat-set with 5 to 20% relaxation to obtain a basis weight of 40 to 100 g / A method for producing a breathable laminate, comprising: bonding an m ² porous film partially using an adhesive so that a non-bonded area ratio is 15 to 55%.

The breathable laminate of the present invention, in which a specific nonwoven fabric and a specific porous film are partially bonded, is formed into a bag shape, puts a heat generating composition, and is used as a paste warmer. Etc., and can be preferably used as a disposable warmer packaging material.
Moreover, the dispersibility of the inorganic filler can be improved by kneading and melting the mixed resin containing linear low density polyethylene, low density polyethylene and the inorganic filler with a specific kneading machine, and Further, there is little stretching unevenness at the time of stretching processing, fine pores are generated, the pore volume can be increased, suitable heat sealability can be obtained, and edge breakage at the time of heat sealing can be reduced.
Furthermore, the edge breakage at the time of heat sealing can be reduced by adjusting the stretch ratio at the time of molding the porous film to 3 to 5 times.

  The breathable laminate of the present invention is obtained by bonding a specific thermoplastic long-fiber nonwoven fabric and a specific porous film. When the air-permeable laminate of the present invention is used in a disposable body warmer, the porous film has fine holes that can adjust the air permeability and moisture permeability necessary for heat generation of the disposable body warmer. Further, the long fiber nonwoven fabric is used for the purpose of protecting and reinforcing the porous film and improving bag-making processability.

  The thermoplastic long-fiber nonwoven fabric used in the present invention is not particularly limited, but a spunbonded long-fiber nonwoven fabric that is relatively thin and excellent in strength and abrasion resistance is preferable. Examples of the fibers constituting the nonwoven fabric include polyamide fibers such as nylon 6, nylon 66 and copolymer polyamide, polyester fibers such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and copolymer polyester, polyethylene and Polyolefin fibers such as polypropylene can be used. Alternatively, a composite fiber such as a core-sheath structure using polyethylene terephthalate for the core and polyethylene for the sheath may be used.

The long-fiber nonwoven fabric used in the present invention is preferably a nonwoven fabric produced by a spunbond method, has a partial thermocompression bonding ratio (embossed area ratio) of 5 to 25%, preferably 7 to 20%, and a basis weight of 15 to 50 g / m ² , preferably 20 to 40 g / m ² . When the partial thermocompression bonding rate is less than 5% or the basis weight is less than 15 g / m ² , the strength and the wear resistance are lowered. On the other hand, when the partial thermocompression bonding rate exceeds 25% or the basis weight exceeds 50 g / m ^2. Strength and wear resistance are increased, but there are problems such as a hard texture.

Furthermore, the nonwoven fabric is a spunbond nonwoven fabric that has been embossed, and is particularly preferably a spunbond nonwoven fabric that has been embossed by a hot embossing roll. The shape of the embossing in the above embossing is not particularly limited, and examples thereof include a rectangle and a circle. Moreover, although the area per emboss is not specifically limited, 0.1-10 mm < ² > is preferable, More preferably, it is 0.3-5 mm < ² >. If the area is less than 0.1 mm ² , the area is too small to obtain the strength by heat fusion, and if it exceeds 10 mm ² , the distance between each emboss increases, so the wear resistance decreases. .

  The porous film in the breathable laminate of the present invention is preferably composed of a mixture of linear low density polyethylene, low density polyethylene and an inorganic filler. The porous film having such a configuration has the advantages that the intermediate modulus can be improved, the porous film can be made porous by stretching the unstretched film, and stretching unevenness can be reduced.

The linear low density polyethylene is a linear polyethylene obtained by polymerizing ethylene and an α-olefin monomer having 4 to 8 carbon atoms. As the α-olefin monomer used in 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, from the viewpoint of improving heat-sealability at a lower temperature, a so-called metallocene linear low-density polyethylene (metallocene LLDPE) prepared using a metallocene catalyst is particularly used. preferable.

The metallocene catalyst linear low density polyethylene preferably has a density of 0.90 to 0.94 g / cm ³ , an MFR at 190 ° C. of 1 to 15 g / 10 min, and a melting point of 101 to 125 ° C. . Moreover, it is preferable to mix two or more types having different densities. For example, by blending a low-density and low-melting linear low-density polyethylene, the solution viscosity can be adjusted, and the extrusion processability and the bag making process can be adjusted. It is possible to improve the heat sealability.

The density of the low density polyethylene, that is, the low density polyethylene of the high pressure method is preferably 0.900 to 0.930 g / cm ³ , more preferably 0.910 to 0.925 g / cm ³ . Moreover, although MFR in 190 degreeC of a high pressure method low density polyethylene is not specifically limited, 1.0-3.0 g / 10min is preferable, More preferably, it is 1.5-2.5 g / 10min.
In addition, the density in this invention shall mean the density obtained based on JISK6922-2 and JISK7112. Moreover, MFR in this invention can be measured based on ISO1133 (JISK7210).

  The porous film used in the present invention preferably contains an inorganic filler. The inorganic filler plays a role of making the film porous by generating voids (pores) around the filler by stretching. Examples of such inorganic fillers include talc, silica, stone powder, zeolite, alumina, aluminum powder and iron powder, as well as metal carbonates of carbonates such as calcium carbonate, magnesium carbonate, magnesium carbonate-calcium and barium carbonate, magnesium sulfate and 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, and Examples thereof include metal hydrates (hydrated metal compounds) such as magnesium oxide-nickel oxide hydrate and magnesium oxide-zinc oxide hydrate. Of these, calcium carbonate and barium sulfate are preferred. The shape of the inorganic filler is preferably particulate from the viewpoint of forming voids (pores) by stretching. That is, as the inorganic filler, inorganic particles made of calcium carbonate are preferable. As the inorganic filler, those treated with a saturated fatty acid are preferably used.

  The particle size of the inorganic filler is preferably 1.0 to 10 μm, more preferably 2.0 to 7.0 μm, and particularly preferably 2.50% average particle size (D = 50%) in particle size distribution measurement. 5 to 5.0 μm. When the particle size is in this range, the void-forming property is improved by stretching, and film breakage and poor appearance are suppressed. If the particle size is less than 1 μm, poor dispersion tends to occur and aggregation tends to occur. On the other hand, if it exceeds 10 μm, the amount added to the resin can be increased, but the pore diameter is increased during stretching, the air permeability is increased, the moisture permeability is decreased, and the inorganic filler is largely removed during stretching. It becomes easy to produce a through-hole.

  The content of the inorganic filler is preferably 35 to 50 wt%, more preferably 37 to 48 wt%, particularly preferably 40 to 47 wt% with respect to the total weight of the film. When the content is within this range, the void processability during stretching is good, and tearing and poor appearance during film formation are suppressed. If the inorganic filler is less than 35%, the void formability is lowered. On the other hand, if it exceeds 50 wt%, the void formability is improved, but the air permeability becomes excessive, and the inorganic filler is likely to fall off, pinholes, tears, and appearance defects during the stretching process.

  When the porous film used in the present invention is blended in a specific range of the polyethylene resin and the inorganic filler, desired film characteristics and heat sealability can be obtained. That is, a mixed resin composed of 40 to 62 wt% of linear low density polyethylene, 2 to 10 wt% of high density low density polyethylene, and 35 to 50 wt% of inorganic filler is mixed and dispersed by a twin screw kneading extruder or the like. Preferably used.

  In the porous film used in the present invention, various additives such as a colorant, an antioxidant, an antioxidant, an ultraviolet absorber, a flame retardant and a stabilizer are blended within a range not impairing the effects of the present invention. May be.

  The porous film in the present invention can be produced by a melt film formation method. Of these, the T-die method is preferable. For example, the polyolefin resin, inorganic filler, and if necessary, various additives are mixed and dispersed by biaxial kneading extrusion, etc., once pelletized, and then into a biaxial kneading extruder with a gear pump. Then, an unstretched film is produced by melt extrusion, and the unstretched film is made porous by stretching uniaxially.

The feature of the method for producing the porous film used in the present invention is that the inorganic filler-containing polyethylene resin is once pelletized and then kneaded again with a twin-screw kneading extruder with a gear pump, so that the inorganic filler in the resin Can be uniformly mixed, the dispersibility of the pores can be improved, and fine pores can be produced by stretching, the pore volume can be increased, and a suitable heat-sealing property can be obtained. It is possible to reduce cutting.
The porous film may be subjected to surface activation treatment in order to obtain sufficient adhesive strength, and may be subjected to various treatments such as antistatic treatment as necessary.

  At the time of molding the porous film, the extrusion temperature is preferably 170 to 270 ° C, more preferably 180 to 260 ° C, and particularly preferably 210 to 250 ° C. Moreover, 5-25 m / min of the taking-up speed at the time of unstretched film preparation is preferable, 10-40 degreeC is preferable and the take-up roll temperature (cooling temperature) is 20-30 degreeC more preferably.

As a method for stretching the unstretched film uniaxially, a known and usual stretching method such as a roll stretching method or a tenter stretching method can be used. The stretching temperature is preferably 40-100 ° C, more preferably 50-80 ° C. In addition, in order to prevent heat shrinkage due to changes in air permeability during heat generation of the warmer, heat seal temperature during the bag making process, etc., in a relaxed state of 5 to 20%, the softening point of the film is equal to or higher than the melting point. Heat setting at temperature is preferred. From the viewpoint of making it porous and forming a stable film, the draw ratio (uniaxial direction) is preferably 3 to 5 times, and more preferably 3.5 to 4.5 times.
When the draw ratio is less than 3 times, the generation of voids in the micropores is reduced, the stretch unevenness occurs, and the air permeability and moisture permeability vary. When the draw ratio exceeds 5 times, the air permeability and moisture permeability can be increased. The inorganic filler is dropped from the resin, through holes are formed, the air permeability varies greatly, the orientation of the film is large, and the edges are easily cut during bag making.

The basis weight of the porous film used in the present invention is 40 to 100 g / m ² , preferably 45 to 90 g / m ² , more preferably 50 to 80 g / m ² . When the basis weight is 40 g / m ² or more, and when the basis weight is 100 g / m ² or less, air permeability, moisture permeability, and bag-making processability are improved. If the basis weight is less than 40 g / m ² , tearing occurs and appearance quality and void formation of fine holes are reduced. On the other hand, if it exceeds 100 g / m ² , pinholes disappear and appearance quality is improved. It is not preferable because it becomes hard, does not have a soft feeling, becomes unusable and becomes expensive.

The porous film used in the present invention has a median diameter of 1.0 μm or less, preferably 0.2 to 0.6 μm, more preferably, as measured by mercury intrusion in a pore distribution range of 0.025 to 3.0 μm. Is 0.3 to 0.5 μm. The pore volume is 0.30 ml / g or more, preferably 0.40 to 0.60 ml / g, more preferably 0.45 to 0.60 ml / g. The pore specific surface area is preferably 5.0 m ² / g or more, more preferably 5.5 to 10 m ² / g, and particularly preferably 6.0 to 10 m ² / g. When the median diameter, pore volume, and pore surface area of the pore distribution measurement value in this region are in the above ranges, the pore configuration has many small voids, and variation in air permeability and moisture permeability can be reduced. . Therefore, even in the small size of the disposable body warmer, uniform air permeability and moisture permeability can be obtained, and the maximum heat generation temperature and heat generation duration of the body warming characteristics are improved.

  The stress at the time of 10% elongation of the porous film used in the present invention is 5 N / 10 mm or more, preferably 6 to 15 N / 10 mm, more preferably 7 to 12 N / 10 mm. The high stress at 10% elongation makes it difficult for the film to stretch due to tension when the porous film and the nonwoven fabric are bonded to each other, so the influence of processing operations on the air permeability and moisture permeability of the warmer product can be reduced. .

The Oken type air permeability of the porous film used in the present invention is preferably 500 to 15000 seconds / 100 cc, more preferably 700 to 10000 seconds / 100 cc, and particularly preferably 800 to 8000 seconds / 100 cc. Further, the moisture permeability is preferably from 500~2000g / m ² / 24hr, more preferably 500~1800g / m ² / 24hr, particularly preferably 600~1500g / m ² / 24hr. If the air permeability and moisture permeability of the film are within this range, the breathability and moisture permeability of the resulting breathable laminate will be within the intended ranges when bonded with a nonwoven fabric and an adhesive to form a breathable laminate. Is possible.
The air permeability is less than 500 seconds / 100 cc or less than moisture permeability of 500g / m ² / 24hr, the resulting breathable laminate when Cairo product, outside the range maximum temperature, such as the stable temperature, duration can be used May occur.

In the present invention, the method of laminating the nonwoven fabric and the porous film is preferably a method of laminating via an adhesive. The adhesive to be used is not particularly limited as long as the air permeability and moisture permeability of the obtained breathable laminate can be controlled within the ranges described below, and a known adhesive used for bonding a nonwoven fabric and a porous film, etc. Can be used.
For example, rubber-based (natural rubber, styrene-based elastomer, etc.), urethane-based (acrylic urethane-based), polyolefin-based (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 can be used. Moreover, the said adhesive agent can be used individually or in combination of 2 or more types. Among these, two-component polyester resins and polyurethane resins are preferable.

Further, the adhesive may be an adhesive having any form, and is not particularly limited, but a dry laminating method using a reactive resin such as a two-component urethane resin is preferable.
Furthermore, it can be applied by melting by heat, and can be applied directly to a non-woven fabric to form an adhesive layer. In the heat-sealed part, a larger adhesive force can be obtained by heat-sealing. Since it has an advantage, a hot melt type (hot melt type) adhesive is preferably used. As such an adhesive, a polyamide-based or polyester-based hot-melt adhesive is preferable, and a thermoplastic polyamide-based hot-melt adhesive or a thermoplastic polyester-based hot-melt adhesive is more preferable.

The specific method of laminating the nonwoven fabric and the porous film varies depending on the type of the adhesive and is not particularly limited. However, the adhesive such as a two-component polyester resin or urethane resin is porous with a gravure roll. A dry laminate or the like that is applied to the film surface and then laminated and adhered is preferably used. In this case, since the application area of the adhesive affects the adhesive strength, air permeability and moisture permeability, it is necessary to consider the shape of the gravure plate and the non-bonded area ratio. For example, the gravure plate is preferably a diagonal lattice pattern from the viewpoint of scratching by the doctor. Further, since the bonding area ratio between the nonwoven fabric and the film affects the air permeability and moisture permeability of the air-permeable laminate, the non-bonding area ratio is preferably 15 to 55%, more preferably 20 to 50%. When the non-bonded area ratio is less than 15%, high adhesive strength can be obtained, but air permeability and air permeability are reduced. On the other hand, if it exceeds 55%, the air permeability and moisture permeability are improved, but the adhesive strength is lowered.
Moreover, when using a hot-melt-type adhesive agent, the method of bonding a porous film after apply | coating an adhesive agent on a nonwoven fabric is used preferably. It is possible to use a known and commonly used method used as a hot melt adhesive coating method, and it is not particularly limited. For example, from the viewpoint of maintaining air permeability, application by spray coating, stripe coating, dot coating Is preferred.

Although the application amount (solid content) of the adhesive is not particularly limited, it is preferably ² to 10 g / m ² , more preferably 3 to 8 g / m ² from the viewpoints of adhesiveness and economical efficiency of the heat seal part during bag formation. m ² .
Further, the bonding strength between the nonwoven fabric and the porous film is preferably 1 N / 25 mm or more, more preferably 2 to 15 N / 25 mm, and particularly preferably 3 to 15 N / 25 mm. When the bonding strength is less than 1 N / 25 mm, peeling may occur during handling of the breathable laminate and use of the product warmer.

OKen ShikiToru air permeability of breathable laminate of the present invention is from 5000 to 240000 seconds / 100 cc, preferably from 7000 to 90000 sec / 100 cc, the moisture permeability is preferably from 200~800g / m ² / 24hr, More preferably, it is 300-750 g / m < ² > / 24hr. If the air permeability and moisture permeability are in this range, it is preferable because the maximum temperature, stable temperature, and duration of the disposable body warmer product can be within appropriate ranges. On the other hand, when the air permeability and moisture permeability are out of this range, it is difficult to bring these characteristics of the disposable body warmer products into an appropriate range.

  The disposable body warmer using the breathable laminate of the present invention has a maximum temperature, a stable temperature and a duration depending on the air permeability and moisture permeability of the bag body, that is, the breathable laminate, and the filling amount and blending of the exothermic composition. Adjustment is possible. Specifically, the maximum temperature can be lowered by reducing the air permeability of the bag. Further, by reducing the moisture permeability, the exothermic reaction can be delayed and the duration can be increased. Furthermore, when the filling amount of the exothermic composition is small, a disposable body warmer having a short duration can be obtained.

As the warmer to be applied, the breathable laminate of the present invention is used on one side of the bag, and the non-breathable film or the laminate of the non-breathable film and the nonwoven fabric is used on the other side. It is obtained by applying an adhesive resin, pasting a release paper, filling a bag with a heat generating composition containing iron, activated carbon, vermiculite, water and salts, and sealing the periphery.
The appropriate ranges of the maximum temperature, stable temperature, and duration of the warmer of the present invention were 50 to 65 ° C., 40 to 60 ° C., and 8 to 15 hours, respectively.

Hereinafter, although this invention is demonstrated based on implementation, this invention is not limited only to these Examples. The measuring method of each characteristic value in the present invention is as follows.
(1) Basis weight (g / m ² ): A sample of length 20 cm × width 25 cm was arbitrarily cut out at three places, the weight was measured, and the average value was calculated by converting the weight per unit area.
(2) Thickness (mm): Ten points were measured arbitrarily under a load of 10 kpa, and an average value was obtained.

  (3) Stress at 10% elongation (N / 10 mm): Three samples of 10 mm in the horizontal direction and 200 mm in the vertical direction (MD direction) are taken arbitrarily, and a constant-length tensile testing machine is used according to JIS-L-1913. It was measured at a grip interval of 10 cm and a tensile speed of 100 mm / min, and the stress at the time of 10% elongation in the vertical direction was obtained as an average value of three sheets.

(4) Oken Air Permeability (sec / 100 cc): Measured with KR-1-8-7MR Oken Air Permeability Measuring Machine manufactured by Asahi Seiko Co., Ltd. (according to JIS-P-8117). The measured value is shown as an average value at three locations.
Further, the air permeability change rate was obtained as follows as the change rate before and after the fir model test.
As a measurement after the fir model test, a square sample of 15 cm in length and 15 cm in width is cut out from the laminate, and stretch rate is set to 5% and 10% using a tensile tester under the conditions of a holding interval of 10 cm and a pulling speed of 10 cm / min. Then, a paddy model test was repeated 10 times in both the vertical and horizontal directions, and the change rate of the air permeability was calculated from the air permeability before and after the test according to the following equation.
Permeability change rate (%) = [(before test−after test) / (before test)] × 100

(5) moisture permeability ^{(g / m 2 / 24hr)} : in accordance with JIS-L-1099 is measured by the cup method (desiccant: calcium chloride 15 g).

(6) Pore distribution: The pore distribution is measured by mercury porosimetry.
Uses a pore distribution measuring device (Type 9250) manufactured by Shimadzu Corporation-Micromeritex Corporation.
Each sample was cut into 12.5 mm × 25 mm, folded, taken in a standard 5 cc cell, and measured under conditions of an initial pressure of 20 kPa. Mercury parameters were measured at a mercury contact angle of 130 degrees and a mercury surface tension of 485 dynes / cm.
<Median diameter>: Means an X-axis value corresponding to an intermediate value between the minimum value and the maximum value of the Y-axis of the integrated pore distribution.
<Pore volume>: A value obtained by dividing the integrated value of the pore volume into which mercury has been injected up to the maximum pressure at the time of measurement by the sample weight.
<Pore surface area>: The surface area of a pore assumed to have a geometric cylindrical shape, calculated from the relationship between the pressure in the measurement range and the amount of mercury injected.

(7) Partial thermocompression bonding ratio (embossed area ratio): The surface of the nonwoven fabric was observed with a microscope (magnification 20 times), and the embossed part in the measurement region (10 mm (MD direction) × 10 mm (TD direction)) The area ratio (area%) was measured (calculated) and used as the embossed area ratio (the following formula).
Embossed area ratio (%) = area of embossed part (mm ² ) / 100 × 100
In addition, it measured about the single side | surface of the nonwoven fabric (n = 5), and made the average value the embossed area ratio of the said nonwoven fabric.

(8) Bonding strength (N / 25 mm): Conforms to T-type peeling according to JIS-K-6854-3.
Three samples of a breathable laminate having a width of 25 mm and a length of 200 mm were taken from the vertical direction, and the peel strength was measured at a tensile speed of 100 mm / min and a gripping interval of 50 mm using a constant length tensile tester, and the average value is shown. .

(9) Seal strength (N / 15 mm): Using a heat sealing machine, the surface temperature above and below the seal bar is set to 150 ° C., the seal width is 5 mm, the pressure is 2 kg / cm ² , and the time is 1 second. After heat-sealing, three samples each having a width of 15 mm and a length of 100 mm were taken from the vertical direction and the horizontal direction, and using a constant-length tensile tester, the peel strength was measured at a pulling speed of 300 mm / min and a grip interval of 30 mm. Measured and shown as an average value.

  (10) Preparation of warmers: Samples each having a width of 95 mm and a length of 130 mm are cut from a breathable laminate and a laminate of a nonwoven fabric and a non-breathable film (LLDPE 70 μm), and a porous film and a non-breathable film are formed inside. Make a bag by heat-sealing in three directions, and put 40 g of a heat-generating composition for disposable body warmers (a heat-generating composition containing iron, activated carbon, vermiculite, water and salts) into the bag, and JIS- In accordance with S-4100, surface temperature, duration, etc. were measured to evaluate the warmer specifications (heat seal conditions: seal width 5 mm, temperature 150 ° C., time 1 second).

(11) Bag-making processability: The tear, edge breakage, and seal failure during bag-making process in (11) above were visually observed and evaluated according to the following criteria.
○: No tearing, edge breakage, or sealing failure during bag making.
(Triangle | delta): It is a grade which the edge cut | disconnection at the time of bag making process arises a little.
X: Many tears, edge breaks, and poor seals occur during bag making.

[Example 1]
As the non-woven fabric, a polyester long-fiber non-woven fabric manufactured by a spunbond method (embossed area ratio 11%, basis weight 25 g / m ² ) was used. In addition, the area per emboss of the said nonwoven fabric is 1.0 mm < ² >.
Metallocene catalyst linear low density polyethylene (Dow Chemical Co., density 0.915, MFR (190 ° C.) 3.5 g / 10 min) 49 wt%, high pressure low density polyethylene 5 wt%, calcium carbonate (D = 50 %, 4 μm) 45 wt%, and a resin mixture consisting of 1 wt% in total of stearic acid and antioxidant was melt kneaded at 220 ° C. to obtain a mixed raw material. The obtained mixed raw material was melt-extruded by a T-die method using a twin-screw kneading extruder with a gear pump to obtain an unstretched film. The obtained unstretched film was heated at a temperature of 60 ° C. and stretched to a stretch ratio of 4.2 times to obtain a polyethylene-based porous film having a basis weight of 60 g / m ² for uniaxial stretching used in the present invention. Table 1 shows the characteristics of the nonwoven fabric and the porous film.

  Next, these nonwoven fabrics and porous films are slanted lattice gravure plates with a non-bonded area ratio of 19% using a two-component polyester resin, and an adhesive is spread on the porous film surface to dry laminate. The breathable laminated body of the present invention was obtained by laminating by the method. Furthermore, a warmer was produced using the obtained air-permeable laminate and evaluated. Table 2 shows the characteristics of the breathable laminate and the body warmer. From Table 2, it can be seen that the maximum temperature, the stable temperature, the duration, and the like of the obtained disposable body warmer are in an appropriate range.

[Example 2]
As the nonwoven fabric, a polyamide long fiber nonwoven fabric (embossed area ratio 6%, basis weight 40 g / m ² ) manufactured by a spunbond method was used. In addition, the area per emboss of the said nonwoven fabric is 0.14 mm < ² >.
Metallocene catalyst linear low density polyethylene (Dow Chemical Co., density 0.915, MFR (190 ° C.) 3.5 g / 10 min) 53 wt%, high pressure low density polyethylene 5 wt%, calcium carbonate (D = 50) %, 4 μm) 41 wt%, and a resin mixture consisting of 1 wt% in total of stearic acid and antioxidant was melt kneaded at 220 ° C. to obtain a mixed raw material. The obtained mixed raw material was melt-extruded by a T-die method using a twin-screw kneading extruder with a gear pump to obtain an unstretched film. The obtained unstretched film was heated at a temperature of 60 ° C. and stretched to a stretch ratio of 4.5 times to obtain a uniaxially stretched polyethylene-based porous film having a basis weight of 60 g / m ² used in the present invention. Table 1 shows the characteristics of the nonwoven fabric and the porous film.

  Next, these nonwoven fabrics and porous films are slanted lattice gravure plates with a non-bonded area ratio of 42% using a two-component polyester resin, and an adhesive is spread on the porous film surface to dry laminate. The breathable laminated body of the present invention was obtained by laminating by the method. Furthermore, a warmer was produced using the obtained air-permeable laminate and evaluated. Table 2 shows the characteristics of the breathable laminate and the body warmer. From Table 2, it can be seen that the maximum temperature, the stable temperature, the duration, and the like of the obtained disposable body warmer are in an appropriate range.

[Example 3]
Using the nonwoven fabric and porous film of Example 1, breathable laminates having different bonding areas were obtained as follows. Using a two-component polyester resin of the same resin as in Example 1, an oblique lattice pattern gravure plate with a non-bonded area ratio of 36%, and an adhesive is distributed on the porous film surface and pasted by a dry laminate method In addition, a breathable laminate of the present invention was obtained. Furthermore, a warmer was produced using the obtained air-permeable laminate and evaluated. Table 2 shows the characteristics of the breathable laminate and the body warmer. From Table 2, it can be seen that the maximum temperature, the stable temperature, the duration, and the like of the obtained disposable body warmer are in an appropriate range.

[Example 4]
Metallocene catalyst linear low density polyethylene (Dow Chemical Co., density 0.915, MFR (190 ° C.) 3.5 g / 10 min) 55 wt%, high pressure method low density polyethylene 3 wt%, calcium carbonate (D = 50 %, 4 μm) 41 wt%, and a resin mixture consisting of 1 wt% in total of stearic acid and antioxidant was melt kneaded at 220 ° C. to obtain a mixed raw material. The obtained mixed raw material was melt-extruded by a T-die method using a twin-screw kneading extruder with a gear pump to obtain an unstretched film. The obtained unstretched film was heated at a temperature of 60 ° C. and stretched to a stretch ratio of 4.5 times to obtain a uniaxially stretched polyethylene-based porous film having a basis weight of 60 g / m ² used in the present invention. The properties of the obtained porous film are shown in Table 1.

  Next, the obtained porous film and the nonwoven fabric described in Example 2 were used in a two-part polyester resin, and an oblique lattice pattern gravure plate with a non-bonded area ratio of 36%, and an adhesive was applied to the porous film surface. This was spread and bonded by a dry laminating method to obtain a breathable laminate of the present invention. Furthermore, a warmer was produced using the obtained air-permeable laminate and evaluated. Table 2 shows the characteristics of the breathable laminate and the body warmer. From Table 2, it can be seen that the maximum temperature, the stable temperature, the duration, and the like of the obtained disposable body warmer are in an appropriate range.

[Example 5]
Metallocene catalyst linear low density polyethylene (Dow Chemical Co., density 0.915, MFR (190 ° C.) 3.5 g / 10 min) 54 wt%, high pressure low density polyethylene 5 wt%, calcium carbonate (D = 50) %, 7 μm) 40 wt%, a mixed resin consisting of 1 wt% in total of stearic acid and antioxidant was melt kneaded at 220 ° C. to obtain a mixed raw material. The obtained mixed raw material was melt-extruded by a T-die method using a twin-screw kneading extruder with a gear pump to obtain an unstretched film. The obtained unstretched film was heated at a temperature of 60 ° C. and stretched to a stretch ratio of 4.5 times to obtain a uniaxially stretched polyethylene-based porous film having a basis weight of 70 g / m ² used in the present invention. The properties of the obtained porous film are shown in Table 1.

  Next, the obtained porous film and the nonwoven fabric described in Example 1 were used in a two-part polyester resin, and an oblique lattice pattern gravure plate having a non-bonded area ratio of 52%, and an adhesive was applied to the porous film surface. This was spread and bonded by a dry laminating method to obtain a breathable laminate of the present invention. Furthermore, a warmer was produced using the obtained air-permeable laminate and evaluated. Table 2 shows the characteristics of the breathable laminate and the body warmer. From Table 2, it can be seen that the maximum temperature, the stable temperature, the duration, and the like of the obtained disposable body warmer are in an appropriate range.

  The breathable laminate of the present invention has a maximum temperature, a stable temperature, and a duration when used in a disposable body warmer by bonding a porous film and a nonwoven fabric with an appropriate adhesion area ratio and making the air permeability within a specific range. Can be made into an appropriate range, and a disposable hand warmer can be commercialized, and the product is obtained in high yield without tearing, edge breakage, and defective sealing during bag making.

[Comparative Example 1]
Linear low density polyethylene of metallocene catalyst (Dow Chemical Co., density 0.915, MFR (190 ° C.) 3.5 g / 10 min) 62 wt%, high density low density polyethylene 5 wt%, calcium carbonate (D = 50 %, 4 μm) A porous film was obtained in the same manner as in Example 1 except that a mixed resin consisting of 32 wt%, stearic acid and antioxidant in total 1 wt% was melt kneaded at 220 ° C. to obtain a mixed raw material. . The properties of the obtained porous film are shown in Table 1.
Next, the obtained porous film and the nonwoven fabric described in Example 1 were used in a two-part polyester resin, and an oblique lattice pattern gravure plate having a non-bonded area ratio of 52%, and an adhesive was applied to the porous film surface. It spread and bonded together by the dry lamination method, and the air permeable laminated body was obtained. Furthermore, a warmer was produced using the obtained air-permeable laminate and evaluated. Table 2 shows the characteristics of the breathable laminate and the body warmer. From Table 2, it can be seen that even if the non-bonded area ratio is increased, the air permeability as a disposable warmer is low, the maximum temperature and the stable temperature are low, and the characteristics are not appropriate for the warmer.

[Comparative Example 2]
Linear low density polyethylene of metallocene catalyst (Dow Chemical Co., density 0.915, MFR (190 ° C.) 3.5 g / 10 min) 41 wt%, high density low density polyethylene 5 wt%, calcium carbonate (D = 50 %, 4 μm) A porous film was obtained in the same manner as in Example 1 except that a mixed resin consisting of 53 wt% and stearic acid and an antioxidant totaling 1 wt% was melt kneaded at 220 ° C. to obtain a mixed raw material. . The properties of the obtained porous film are shown in Table 1.
Subsequently, the obtained porous film and the nonwoven fabric described in Example 1 were used with a two-component polyester resin, an adhesive was distributed on the porous film surface by a gravure method, and the non-bonded area ratio was 19%. With an oblique lattice pattern gravure plate, an adhesive was spread on the surface of the porous film and bonded by a dry laminating method to obtain a breathable laminate. Furthermore, a warmer was produced using the obtained air-permeable laminate and evaluated. Table 2 shows the characteristics of the breathable laminate and the body warmer. From Tables 1 and 2, it can be seen that the pores of the porous film are increased and the edges are easily cut off, and the bag making process suitability of the disposable body warmer cannot be obtained.

[Comparative Example 3]
A porous film was obtained in the same manner as in Example 5 except that the resin composition was not added with low-density polyethylene in the high-pressure method and that the unstretched film was stretched at a stretch ratio of 5.5. Using the porous film, a breathable laminate and a disposable body warmer were obtained in the same manner as in Example 5. Tables 1 and 2 show the characteristics of the porous film, the air-permeable laminate, and the body warmer. As for the porous film, there are many problems such that the inorganic filler is often dropped during the stretching process, the edge breakage occurs frequently during the bag making process, and the obtained disposable warmer has a higher maximum temperature and bulges.

  The breathable laminate of the present invention has good heat sealability when used as a bag component of a disposable body warmer, is excellent in the product characteristics of the disposable body warmer such as the maximum heat generation temperature and the heat generation duration time, and when heat sealed. There are few edge breaks etc. and it is excellent in productivity, and it is useful as a bag body structural member of a disposable body warmer.

Claims (7)

A breathable laminate the nonwoven fabric and the porous film is bonded, the nonwoven fabric is partially thermocompression bonding index is composed 5-25% and a basis weight of 15 to 50 g / m ² Thermoplastic long-fiber nonwoven fabric, the The porous film contains 40 to 62 wt% of linear low density polyethylene, 2 to 10 wt% of low density polyethylene and 35 to 50 wt% of inorganic filler with respect to the total weight of the film as constituent components, and has a basis weight of 40. ~ 100 g / m ² , median diameter and pore volume by mercury intrusion method are 1 μm or less and 0.3 ml / g or more, respectively, and 10% elongation stress is 5 N / 10 mm or more porous film A breathable laminate having an air permeability of 5,000 to 100,000 seconds / 100 cc.   The breathable laminate according to claim 1, wherein the inorganic filler is calcium carbonate having a 50% average particle diameter of 1 to 10 µm.   The breathable laminate according to claim 1 or 2, wherein the thermoplastic long fiber nonwoven fabric comprises at least one selected from polyester fibers, polyamide fibers, and polyolefin fibers.   The breathable laminate according to any one of claims 1 to 3, wherein the porous film has a draw ratio of 3 to 5 times.   The breathable laminate according to any one of claims 1 to 4, wherein the joining is partial joining, and a non-joining area ratio is 15 to 55%.   Disposable body warmer using the breathable layered product according to any one of claims 1 to 5 as a bag constituent member. A thermoplastic long fiber nonwoven fabric partially thermocompressed with a basis weight of 15 to 50 g / m ² obtained by melt spinning a thermoplastic resin by a spunbond method, and 40 to 62 wt% of linear low density polyethylene as a constituent component, A mixed resin containing 2 to 10 wt% of low density polyethylene and 35 to 50 wt% of an inorganic filler is mixed and dispersed by a twin screw kneading extruder and then used in a twin screw kneading extruder with a gear pump using a T-die method. The unstretched film formed by melt film formation was stretched 3 to 5 times on one axis at a stretching temperature of 40 to 100 ° C., and then heat-set with 5 to 20% relaxation, and the basis weight was 40 to 100 g / m ² . A method for producing a breathable laminate, wherein a porous film is partially bonded using an adhesive so that a non-bonded area ratio is 15 to 55%.