JP2804426B2 - Cairo sheet substrate, adhesive member, and disposable body warmer provided with these - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive member such as a plastic sheet substrate and an adhesive sheet having excellent heat sealing strength and used for, for example, disposable warmers.
A disposable body warmer comprising them .

[0002]

2. Description of the Related Art A disposable body warmer is known as a household article which can be freely attached to clothes or the like with an adhesive or an adhesive sheet. For example, as shown in FIG. 1, a heat seal layer 1 made of ethylene-vinyl acetate copolymer (EVA) and a layer 2 made of polyethylene (PE)
The heat seal portion 3 is formed by the heat seal layer 1 of the multi-layer plastic sheet base material A composed of two or three layers and the porous film B usually made of polyethylene, and the heating element 4 such as iron powder is sealed. Become. An adhesive layer 5 is provided on the film layer 2, and the surface thereof is further provided with a separator 6.
Become protected.

[0003]

However, the ethylene-vinyl acetate copolymer used in the heat seal layer of the conventional sheet base has a vinyl acetate content of 10%.
And the strength of heat sealing with the porous film was low, the film was torn therefrom, or the workability on the production line was poor, and a long time was required. Further, depending on the conditions, the obtained heat seal strength varied and the reliability was poor.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to improve the conventional problems, and by using a specific material as a heat seal layer of a base material, sufficient heat seal strength can be obtained. Sheet base material for Cairo that can be manufactured well ,
Adhesive member using this, and disposable
Offer Iro .

[0005] That is, the present invention is a sheet base material for a warmer, comprising two or more plastic film layers, at least one side of which is a heat seal layer, wherein the heat seal layer has a vinyl acetate content of 10% or more. Ethylene
Vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer ,
A sheet base material for a warmer, comprising at least one selected from low-density polyethylene, an adhesive member using the same, and a disposable warmer provided with the same.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a cross-sectional view showing an example of the sheet base material of the present invention, and a heat-sealing layer 1 and a film layer 2 are laminated to form a sheet base material A. Film layer 2
A pressure-sensitive adhesive layer 5 is provided on the top if necessary, and the surface thereof is protected by a separator 6.

The heat seal layer 1 in the present invention comprises an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10% or more, preferably 15 to 17%, and other materials having a low melting point (7
(Approximately 0 to 80 ° C.) Ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer , low-density or ultra-low-density polyethylene is used, and a single or a mixture of two or more thereof is used. When the vinyl acetate content or the melting point is out of the above range, there is a drawback that the heat adhesion is poor and the reliability of the heat-sealed portion is lacking. The thickness is not particularly limited, but is usually 70
The thickness may be about 100 μm.

[0008] Film layer 2 other than the heat seal layer is not particularly limited, for example, polyester, Po
Ethylene, polypropylene, ethylene-propylene
A single polymer selected from polymers or a mixture of two or more polymers is used. The film layer may be a single layer or a multilayer of two or more layers. The thickness is not particularly limited, but may be generally about 50 to 70 μm. The difference between the melting points of the heat seal layer and the other film layers is preferably at least 5 ° C. or more.

The method of laminating the film layer and the heat seal layer is not particularly limited, but the sheet substrate of the present invention can be obtained by, for example, an inflation method or a T-die extrusion method.

The pressure-sensitive adhesive layer 5 provided as required
Is not particularly limited, and examples thereof include acryl-based and rubber-based ones. In particular, an acrylic-based emulsion-type and a rubber-based natural rubber-based and styrene-based synthetic block polymer are preferably used. In addition, this type of polymer
Since it is easy to make a hot melt, there is also an advantage that productivity is improved and pollution can be eliminated as compared with the solvent type. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is usually preferably about 20 to 40 μm. The pressure-sensitive adhesive composition may contain a tackifier, an oil (softening agent), a liquid resin, an antioxidant, and the like.

The heat seal layer of the substrate sheet of the present invention comprises:
As shown in FIG. 1, a heat treatment is usually performed with a porous film B made of polyethylene, and a heating element 4 such as iron powder is wrapped to obtain a warmer. The method of heat sealing is not particularly limited, but it can be obtained by pressure bonding with a heat sealer at an appropriate temperature and pressure.

Here, the heat seal strength of the heat seal layer in the vertical and horizontal directions at 80 ° C. (the maximum strength of T peeling at a tensile speed of 300 mm / min) is at least 100 g /.
It is practically preferable that the width be 25 mm or more , particularly 500 g / 25 mm or more, but it is not limited to this.

[0013]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0014] In 180 ° C. according to Example 1 T-die extrusion method, a thickness of 30μm et
Tylene-methyl methacrylate copolymer (EMMA)
(Copolymerization ratio is weight ratio, ethylene / methyl methacrylate
Sheet = 82.5 / 17.5) layer and a high-density polyethylene layer having a thickness of 70 μm having a two-layer structure.

[0015] The heat sealing layer of the sheet base material is E
70 ° C., 80 ° C., 90 ° C., 100 ° C. on a 50 μm-thick polyethylene porous film to form an MMA layer.
℃, 110 ℃, 120 ℃, 130 ℃, at each temperature of 140 ° C., and pressed at a heat sealer under a pressure of 1.0 kg / cm ^2. This was cut into 25 mm widths, and the results of measuring the maximum strength when a T peel test was performed at a tensile speed of 300 mm / min are shown in FIGS. 3 (1) and 3 (2). Here, the heat seal strength in the vertical and horizontal directions at 80 ° C. is shown in Table 1.

As the heat seal layer in Example 1,
Ethylene-methyl methacrylate copolymer (EMM
A) Instead of layer, ultra low density polyethylene (VLDP)
E) (mp 80 ° C.), ethylene - vinyl acetate copolymer (EVA) (15% vinyl acetate content), ethylene - ethyl acrylate copolymer (EEA) (mp 80 ° C.) (co
The polymerization ratio is a weight ratio, ethylene / ethyl acrylate = 9.
A sheet substrate was obtained in the same manner as in Example 1 except that each was changed to 1/9) . Table 1 shows the heat seal strength at 80 ° C. in the vertical and horizontal directions.

As a heat seal layer in Example 1
Ethylene-methyl methacrylate copolymer (EMM
A) A sheet substrate was obtained in the same manner as in Example 1 except that the layer A) was changed to an ethylene-vinyl acetate copolymer (vinyl acetate content 9%) instead of the layer. 70 ° C, 80 ° C, 90 ° C,
FIG. 3 and Table 1 show the heat seal strength in the vertical and horizontal directions at 100 ° C., 110 ° C., 120 ° C., 130 ° C., and 140 ° C. and at 80 ° C.

[0018]

[0019]

The sheet substrate of the present invention has sufficient heat sealing strength at a relatively low temperature, and thus has excellent product reliability and workability in production.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a general disposable body warmer.

FIG. 2 is a cross-sectional view showing an example of the base sheet of the present invention.

FIG. 3 is a graph showing the relationship between heat seal temperature and heat seal strength in Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat seal layer 2 Film layer 3 Heat seal part 4 Heating element 5 Adhesive layer 6 Separator A Sheet base material B Porous film

Claims (5)

(57) [Claims] 1. A hot-sealing sheet substrate comprising two or more plastic film layers, at least one surface of which is a heat-sealing layer, wherein the heat-sealing layer has a vinyl acetate content of 10% or more. Vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene
A sheet base material for a warmer, comprising at least one selected from the group consisting of a methyl-methacrylate copolymer and a low-density polyethylene. 2. The heat sealing layer at 80 ° C.
Transverse heat seal strength of at least 100 g / 25
2. The chimney according to claim 1, wherein the width is at least
B sheet base. 3. A film layer other than the heat sealing layer is
Ester, polyethylene, polypropylene, ethylene
-From at least one selected from propylene copolymers
The seat base for a warmer according to claim 1, wherein
Wood. 4. A pressure-sensitive adhesive member for a warmer, comprising the sheet substrate according to claim 1 and a pressure-sensitive adhesive layer. 5. A disposable body warmer comprising the sheet substrate according to claim 1 or an adhesive member.