JPH1156894A - Packaging material for disposable body warmer and bag for body warmer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging material suitable for a disposable body warmer which is excellent in low-temp. sealability, extraneous material sealability and hot tack property and is inexpensive and a bag for the throw-away body warmer obtd. by forming this packaging material as a bag. SOLUTION: This packaging material for the disposable body warmer consists of a laminate composed of a span bonded nonwoven fabric layer (preferably having a hot melt area rate of 10 to 30%) made of polypropylene and a resin layer contg. a film layer consisting of a resin (preferably having a melting point of 70 to 120 deg.C) contg. straight chain low density polyethylene(LDPE) produced by using a metallocene catalyst. This bag for the throw-away body warmer is formed by laminating the film layer consisting of the resin contg. the straight chain LDPE as a hot adhesive layer at the time of bag making.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material for disposable warmers and a bag for disposable warmers.
The present invention relates to a disposable body warmer packaging material and a disposable body warmer bag comprising a laminate of a spunbond nonwoven fabric layer and a thermoplastic resin film layer.

[0002]

2. Description of the Related Art A so-called disposable body warmer obtained by storing a composition that generates heat in the presence of air, for example, iron powder, inorganic salt, activated carbon, etc., in a bag is used for various purposes because of its simplicity. Have been. In such a disposable body warmer, a packaging material in which a nonwoven fabric and a resin film are laminated is usually used, and the outer peripheral portion of the packaging material is thermally fused to be used as a bag.

In this case, the performance required as a packaging material is as follows. In other words, the non-woven fabric has a soft touch because it is a part that directly touches the skin, and has sufficient strength to protect the resin film laminated inside and prevent the bag from breaking. That it is not deformed or deteriorated by heat during bag-making (heat resistance), while, on the resin film side, even if the heat-generating composition adheres to the sealing surface, no defective sealing occurs. (Good sealing property for foreign substances), Heat-weighted part of heat-generating composition should not be torn once (sufficient hot-tack property), Heat-generating composition damages film and breaks bag (High piercing strength), and low sealing temperature (low-temperature sealing property) to contribute to the improvement of production speed.

[0004] Conventionally, as such a disposable body warmer packaging material, due to its good texture, a nylon spunbonded nonwoven fabric or a polyester nonwoven fabric as a nonwoven fabric layer, a low-density polyethylene film and an ethylene-vinyl acetate copolymer as a resin film layer. Although a coalesced film or a low-density polyethylene film and EMAA (ethylene-methacrylic acid copolymer resin) are used, a nylon nonwoven fabric or a polyester nonwoven fabric is an expensive material for disposable use, and it can be said that it is preferable. Did not. In addition, when using a nonwoven fabric made of a resin that is less expensive than a nylon nonwoven fabric or a polyester nonwoven fabric, if a low-density polyethylene film or an ethylene-vinyl acetate copolymer film is used as the resin layer to be laminated, sufficient heat sealing properties and hot tack properties are obtained. There was a problem of not being expressed.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made from the above viewpoint, and is excellent in low-temperature sealing property, foreign matter sealing property and hot tack property, and is suitable for an inexpensive disposable body warmer. It is an object of the present invention to provide a disposable body warmer bag made of the packaging material.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above object of the present invention can be effectively achieved by laminating a specific spunbonded nonwoven fabric and a thermoplastic film. To complete the present invention. That is, the present invention provides: (1) a disposable product comprising a laminate of a spunbond nonwoven fabric layer made of polypropylene and a resin layer containing a film layer made of a resin containing linear low-density polyethylene produced using a metallocene catalyst. Packaging material for Cairo. (2) A disposable body warmer packaging material consisting of a laminate of a polypropylene spunbonded nonwoven fabric layer and a linear low-density polyethylene resin layer produced using a metallocene catalyst. (3) The heat-fused area ratio of the polypropylene spunbonded nonwoven fabric is 10 to 30%, and the melting point of the resin containing linear low-density polyethylene produced using a metallocene catalyst is 70 to 120 ° C. The packaging material for a disposable body warmer according to (1) or (2). (4) A disposable warmer bag using the disposable warmer packaging material according to any one of (1) to (3), wherein a film layer made of a resin containing the linear low-density polyethylene is formed. It is intended to provide a disposable body warmer bag characterized by being laminated as a thermal adhesive layer at the time of bag.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. 1. Polypropylene Spunbonded Nonwoven Fabric The disposable body warmer packaging material according to the present invention has a layer of a polypropylene spunbonded nonwoven fabric as one layer of the laminate.

[0008] The spunbonded nonwoven fabric refers to a nonwoven fabric manufactured by a known spunbonding method. In the present invention, composite fibers of the spun bond method and the melt blow method, specifically, composite fibers such as spun bond method / melt blow method / spun bond method, and spun bond method /
Compounds such as a melt blow method can also be used. Spunbond nonwovens are usually manufactured by spinning,
It consists of the steps of stretching, opening, collecting and bonding. In the bonding process in nonwoven fabric production,
Usually, the nonwoven web is partially heat-sealed.

[0009] Partial heat fusion refers to joining nonwoven webs together by thermal bonding or the like, rather than joining the entire surface. There is no particular limitation on the method of partial heat fusion, but specifically, a method using an embossing roll or the like having dots (dots), broken lines, or grids or grids as convex portions is preferably performed. . In the present invention, a partially heat-sealed nonwoven fabric is used as a suitable spunbonded nonwoven fabric, and the area ratio of the heat-sealed portion is preferably 10 to 30%, more preferably 12 to 20%. If it is less than 10%, the texture becomes soft, but fluff is likely to occur, and the fibers fall off. If it exceeds 30%, the feel may be hard.

The basis weight of the nonwoven fabric is not particularly limited, but is preferably ^{20 to} 70 g / m ² , preferably 3 to 70 g / m ² .
0 to 50 g / m ² . If it is less than 20 g / m ² , the strength as a bag may be insufficient and the bag may be easily broken. 70g
If it exceeds / m ² , flexibility and sealing properties may be deteriorated. Although the resin used for the spunbonded nonwoven fabric in the present invention is polypropylene, it does not impair the object of the present invention to a polypropylene homopolymer, a polypropylene copolymer containing polypropylene as a main component, or a polypropylene homopolymer or a polypropylene copolymer. This is a concept including a composition with a third component such as various additives added in the range. 2. Resin layer The disposable body warmer packaging material according to the present invention has a resin layer as one layer of the laminate. This resin layer is a single layer of a resin layer containing a resin containing linear low-density polyethylene (LLDPE) produced using at least a metallocene-based catalyst, or a multilayer containing the film layer. (1) A film layer made of a resin containing a linear low-density polyethylene produced using a metallocene-based catalyst The film layer serves as a thermal adhesive layer during bag making.

Here, the linear low-density polyethylene used must be obtained using a metallocene-based catalyst. Examples of the metallocene catalyst include a single-site catalyst (SSC) and a geometrically constrained catalyst (CGC). Specific examples of these metallocene-based catalysts include JP-A-6-192506, JP-A-7-145298, JP-A-7-18151, JP-A-7-145272, and International Publication WO94 / 0685.
There is a catalyst described in Japanese Patent Application Laid-Open No. 9-134140, Japanese Patent Application Laid-Open Nos. WO 93/04317 and WO 96/04317.
Gazette, JP-A-91 / 04255, JP-A-91 / 0425
No. 7 can be mentioned.
More specifically, a cyclopentadienyl group, a mono (di,
There is a catalyst comprising a transition metal complex having a (tri, tetra, penta) methylcyclopentadienyl group or an indenyl group. These metallocene catalysts are usually used in combination with an ionic compound such as an alkylaluminoxane or a boron compound. Ethylene-α having 4 to 18 carbon atoms
-Olefin copolymers are preferred. In the linear low-density polyethylene, the α-olefin having 4 to 18 carbon atoms usually used as a comonomer of the copolymer includes, for example, butene-1, pentene-1, hexene-1, octene-1, nonene-1; Linear α-olefins such as decene-1; dodecene-1; and branched α-olefins such as 3-methylbutene-1; 4-methylpentene-1. 10 linear α-
Olefins are preferred. These α-olefins may be used alone or in combination of two or more. Further, a small amount of a diene component, for example, dicyclopentadiene; ethylidene norbornene; 1,4-hexadiene; 1,9-decadiene; vinyl norbornene may be used in combination. The content of the α-olefin unit in the ethylene-α-olefin copolymer is not particularly limited, and may be appropriately selected depending on the purpose.

The resin containing linear low-density polyethylene produced using the metallocene catalyst has a melting point of 7%.
Those having a temperature of 0 to 120 ° C are preferred. More preferably 85
１１０110 ° C. In the disposable body warmer bag according to the present invention, it is necessary that a film layer made of a resin containing linear low-density polyethylene is laminated as a thermal adhesive layer during bag making. In this case, it is preferable that the melting point of the resin containing the linear low-density polyethylene is lower because the sealing property is improved. May be melt-peeled to break the bag. Also, 120
When the temperature is higher than ° C, the difference from the melting point of the polypropylene resin used for the nonwoven fabric layer becomes small, and the nonwoven fabric layer may be deformed or the stability at the time of high-speed bag-making sealing may be deteriorated, so that the sealing properties may be deteriorated.

[0013] The film layer is to be a heat bonding layer at the time of bag making, and if it has a melting point satisfying the above range, it consists only of a linear low-density polyethylene obtained using a metallocene catalyst. It does not need to be one and may include a linear low-density polyethylene, a low-density polyethylene, or the like obtained by another manufacturing method. That is, a material obtained by blending these other resins with a linear low-density polyethylene obtained using a metallocene catalyst may be used as the material of the film layer. Preferably, only a linear low-density polyethylene obtained using a metallocene catalyst is used. (2) Further, the resin layer may be a single layer of the above-mentioned film layer made of a resin containing linear low-density polyethylene produced using a metallocene catalyst, or another thermoplastic resin may be laminated on this layer. Multiple layers may be used. In the case of a multilayer structure, the film layer made of a resin containing a linear low-density polyethylene produced using a metallocene catalyst has a structure that becomes a seal layer to be thermally bonded when bag making. is necessary. In the case of a multilayer structure, a two-layer structure composed of a linear low-density polyethylene resin film layer and a low-density polyethylene resin film layer produced using a metallocene catalyst is preferably used. (3) The thickness of the resin layer is preferably 30 to 80 μm, more preferably 40 to 60 μm. If it is less than 30 μm, sufficient piercing strength cannot be obtained, and if it exceeds 80 μm, the heat sealing property is reduced and high-speed production becomes difficult. (4) The material forming the resin layer may be a material to which a third component such as various additives is added as long as the object of the present invention is not impaired. 4. Lamination method of the nonwoven fabric layer and the resin layer The lamination method of the nonwoven fabric layer and the resin layer is not particularly limited, and a known method may be used. For example, extrusion lamination to melt-extrude linear low-density polyethylene produced using a metallocene-based catalyst on a nonwoven fabric, or a resin layer of low-density polyethylene or the like, produced using a nonwoven fabric and a metallocene-based catalyst Polysand laminate in which linear low-density polyethylene is laminated, dry lamination using an adhesive, or the like can be used.

Further, in high-speed production, tandem molding using two T-die extruders is preferably used. 5. Disposable body warmer or disposable body warmer bag (1) Since oxygen is required to generate heat from the exothermic composition in the disposable body warmer, air permeability is required for the disposable body warmer composed of the laminate. To grant,
In that case, a known method such as mechanical perforation with a fine needle or the like may be used. The diameter and number of holes may be appropriately selected according to the purpose. (2) The bag for a disposable body warmer according to the present invention is formed using the above-described packaging material for a disposable body warmer, and a film layer made of a resin containing a linear low-density polyethylene in the packaging material for a disposable body warmer is used. It is obtained by bonding as a thermal bonding layer during bag making. The bag-making method is not particularly limited, and a known method may be used. Specifically, the packaging material for a disposable body warmer is such that a film layer made of a resin containing linear low-density polyethylene directly overlaps. Is preferably used, and a method of processing into a bag shape by stacking two sheets and heat-sealing the four sides with a heat sealing machine is preferably used.

[0015]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The evaluation was based on the following method. (1) Low-temperature sealing property Evaluation was made based on the sealing temperature. The lower the sealing temperature,
This indicates that the low-temperature sealability is good. Specifically, the sealing layers are superimposed on the composite sheet to be measured, and a heat gradient type sealing machine (manufactured by Toyo Seiki Co., Ltd.)
Sealing was performed by heating at a pressure of 2 kg / cm ² for 1 second, and the sealing strength was measured. When the seal temperature was changed and the seal strength reached 1 kg / 15 mm, the temperature was defined as "lower limit seal temperature". (2) Bag making evaluation at the time of filling the contents The filling test was carried out using a one-sided die roll type continuous bag making machine. The heating roll temperature was raised from 110 ° C. to 150 ° C. in steps of 10 ° C. to manufacture a warmer, and bag making evaluation such as sealing at each set temperature was performed. The bag making speed was 60 pieces per minute. [Example 1] Nonwoven polypropylene spunbond (PP spunbond) nonwoven fabric (trade name “Stratec RW2040” manufactured by Idemitsu Petrochemical Co., Ltd., basis weight 40 g / m ² , melting point 163)
, A low-density polyethylene (manufactured by Dow Chemical Company, Affinity-FW1650, melting point 98 ° C) using a metallocene catalyst.
Was extrusion-laminated with a T-die extruder (extrusion temperature: 270 ° C.) at a thickness of 50 μm to obtain a non-breathable two-layer laminated sheet. Further, a part of this non-breathable two-layer laminated sheet was subjected to ventilation processing using a hot needle, to obtain a breathable two-layer laminated sheet. The non-breathable two-layer laminate sheet and the breathable two-layer laminate sheet thus obtained are superimposed so that the linear low-density polyethylene film layers are adhered to each other and supplied as a raw material. A disposable body warmer was obtained by sealing the four sides while filling the exothermic composition (iron powder, water, oxidation promoter and water retention agent) with a filling and sealing machine.

The lower limit sealing temperature was 112 ° C. As for the bag making evaluation at the time of filling the contents, a failure due to insufficient sealing strength occurred at 110 ° C. and 120 ° C., but at 130 ° C. or higher, the sealing failure was resolved and a good product was obtained. Example 2 Low-density polyethylene (manufactured by Nippon Unicar, trade name “NUC polyethylene 8007”, melting point 122 ° C.) on the PP spunbond nonwoven fabric used in Example 1 using a two-head T-die extruder. And low-density linear polyethylene produced using a metallocene-based catalyst (Affinity-FW1650, manufactured by Dow Chemical Company, melting point 98)
° C) at a thickness of 25 µm each, and the nonwoven fabric / LDP
A three-layer laminated sheet made of E / metallocene LLDPE was obtained. A disposable body warmer was manufactured in the same procedure as in Example 1.

The lower limit sealing temperature was 115 ° C. As for the bag making evaluation at the time of filling the contents, a failure due to insufficient sealing strength occurred at 110 ° C. and 120 ° C., but at 130 ° C. or higher, the sealing failure was resolved and a good product was obtained. Example 3 30 μm thick linear low-density polyethylene (Affinity-PF1140 manufactured by Dow Chemical Company, melting point 94 ° C.) manufactured using a metallocene catalyst
m and the PP spunbond nonwoven fabric used in Example 1 and the LDPE resin used in Example 2 were 20 μm thick.
Were laminated while being melt-extruded. A disposable body warmer was manufactured in the same procedure as in Example 1.

The lower limit sealing temperature was 109 ° C. As a bag-making evaluation at the time of filling the contents, a good product was obtained at 120 ° C. or higher. [Comparative Example 1] On the PP spunbond nonwoven fabric used in Example 1, a linear low-density polyethylene (manufactured by Idemitsu Petrochemical Co., Ltd., trade name: Moortec 0238CN, melting point 122) was prepared using a metallocene catalyst. C.) using a T-die extruder (extrusion temperature 240 ° C.) to a thickness of 50 μm and extrusion lamination to obtain a two-layer laminated sheet. A disposable body warmer was manufactured in the same procedure as in Example 1.

The lower limit sealing temperature was 128 ° C. Regarding the bag making evaluation at the time of filling the contents, at 130 ° C. or less, more than half of the bags had defective sealing. Good products were obtained at 140 ° C. or higher. [Comparative Example 2] In Example 2, instead of the linear low-density polyethylene produced using the metallocene catalyst,
The procedure was performed in the same manner as in Example 2 except that an ethylene-vinyl acetate copolymer film (vinyl acetate content 10%, melting point 93 ° C.) was used.

The lower limit sealing temperature was 109 ° C. Regarding the bag making evaluation at the time of filling the contents, at each temperature from 110 ° C. to 150 ° C. in increments of 10 ° C., the hot tack property was poor, and the sealing failure that the opening of the seal portion was opened occurred frequently. Reference Example 1 The procedure of Example 3 was repeated, except that the heat-bonded area ratio of the PP spunbonded nonwoven fabric was changed to 8%.

The lower limit sealing temperature and the bag making evaluation at the time of filling the contents were the same as those in Example 3, but relatively fuzzing was observed.

[0022]

According to the present invention, there is provided a packaging material suitable for a disposable body warmer excellent in low-temperature sealing properties, foreign matter sealing properties and hot tack properties, and a disposable body warming bag made of the packaging material. Could be provided at low cost.

Claims (4)

[Claims] 1. A packaging material for a disposable body warmer comprising a laminate of a polypropylene spunbonded nonwoven fabric layer and a resin layer containing a film layer made of a resin containing a linear low-density polyethylene produced using a metallocene catalyst. . 2. A disposable body warmer packaging material comprising a laminate of a polypropylene spunbond nonwoven fabric layer and a linear low-density polyethylene resin layer produced using a metallocene catalyst. 3. The heat-sealing area ratio of the polypropylene spunbonded nonwoven fabric is 10 to 30%, and the melting point of the resin containing linear low-density polyethylene produced using a metallocene catalyst is 70 to 120 ° C. Certain claim 1 or 2
A packaging material for a disposable body warmer according to [1]. 4. A disposable warmer bag using the disposable warmer packaging material according to claim 1, wherein a film layer made of a resin containing the linear low-density polyethylene is formed. A bag for a disposable body warmer, which is laminated as a thermal adhesive layer at the time.