JP2002326300A - Granular powder packaging material excellent in heat sealability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging material having air permeability, not leaking a granular powder and having efficient heat salability. SOLUTION: The packaging material is obtained by integrating a melt-blown nonwoven fabric (A-layer) comprising a thermoplastic synthetic resin with a flow starting temperature of 125 deg.C or lower and a nonwoven fabric (C-layer) comprising a synthetic resin with a melting point of 200 deg.C or higher by an adhesive. The air permeability of the packaging material is not more than 55 cm<3> /cm<2> /sec.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture absorbing / releasing agent such as activated carbon or charcoal or silica gel having a moisture absorbing / releasing property for adsorbing an odor or a toxic gas, as well as various granular powders such as an oxygen scavenger and iron oxide for a hot body. It is intended to provide a packaging material capable of efficiently packaging a body.

[0002]

2. Description of the Related Art Conventionally, various nonwoven fabrics manufactured from various resins have been used for various packaging materials. Spunbond made of polypropylene or polyester is also used in many packaging materials.

[0003] Spunbond (Elves) manufactured by Unitika Ltd., whose core is made of polyester and whose sheath is made of polyethylene, is also used as a packaging material that can be easily heat-sealed. However, all of these spunbonds are coarse and are not suitable for packaging powders.

Therefore, a melt blown nonwoven fabric (hereinafter abbreviated as MB), which is finer than spunbond and hard to leak the powder of the contents, is used for the above-mentioned applications. However, since MB has insufficient strength, it is often used by being laminated with high-strength spunbond or other materials. Until now, MBs used for this purpose include:
Polypropylene resins have been used. However, in the case where the packaging material formed by laminating the polypropylene MB is heat-sealed for powder packaging, the heat sealing efficiency is not sufficient, and the adhesion between the polypropylene MB and other materials is insufficient. Had.

[0005]

SUMMARY OF THE INVENTION In view of the foregoing, an object of the present invention is to provide a packaging material which is breathable, does not leak particulate powder, and has an efficient heat sealing property. It is assumed that.

[0006]

According to the present invention, there is provided an MB comprising a thermoplastic synthetic resin having a flow start temperature of 125 ° C. or lower.
By integrating the (A layer) and the nonwoven fabric (C layer) made of a synthetic resin having a melting point of 200 ° C. or more with an adhesive, there is air permeability and efficient heat sealing. It is intended to provide a granular powder packaging material.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The material used for the layer A of the granular powder packaging material excellent in heat sealability of the present invention is a thermoplastic synthetic resin MB non-woven fabric having a flow start temperature of 125 ° C. or less, Examples of the thermoplastic synthetic resin having a flow start temperature of 125 ° C. or lower used herein include various polyolefins and copolymers thereof. Specific examples include an ethylene-octene copolymer and a block copolymer of polyolefin and polystyrene. In particular, SEPS, SEBS, and SEEP, which are block copolymers of polyolefins and polystyrene,
Thermoplastic elastomers such as S are very suitable for the purpose of the present invention.

The basis weight of the layer A used in the present invention is 5 g /
m ² to 150 g / m ² , especially 20 g / m ²
And about 80 g / m ² are preferred. 5g weight
If it is less than / m ² , good heat sealability may not be obtained. On the other hand, if the basis weight exceeds 150 g / m ² , it may be difficult to perform smooth heat sealing.

The layer A used in the present invention is preferably subjected to a heat embossing treatment, preferably a heat calendering treatment, so that the surface of the MB is smoothed. By the smoothing, heat sealing at a higher speed can be performed, and breakage caused by friction with the granular powder to be packaged can be prevented.

[0010] Further, by performing the calendering treatment, the voids between fibers, so-called pore size, are reduced.
The leakage of the powder of the contents can be prevented.

The fiber diameter of the MB obtained from the resin used for the layer A is generally larger than the fiber diameter of the MB obtained from the polyolefin resin. For this reason, only a large pore size can be obtained, which may be insufficient for preventing leakage of powder having a small diameter.

In such a case, an MB (B) comprising one or more polyolefin-based resins is further provided between the A layer and the C layer.
Layer) is preferred. Polyethylene or, particularly, polypropylene is preferably used for the layer B, and the basis weight thereof is desirably about 5 g / m ^{2 to} about 100 g / m ² . If it is less than 5 g / m ² , the effect may be insufficient, and if it exceeds 100 g / m ^{2, it} may be uneconomical, heat conduction during heat sealing may be deteriorated, and high-speed heat sealing may be difficult. is there.

It is economical to bond the A layer and the B layer by thermocompression bonding or the like, but they can also be bonded by using an adhesive.

On the other hand, the material used for the layer C of the granular powder packaging material having excellent heat sealability according to the present invention has a melting point of 20%.
It is a nonwoven fabric made of a synthetic resin having a temperature of 0 ° C. or higher, and the nonwoven fabric used herein is a nonwoven fabric made of polyester or polyamide, particularly including spunbond. In order to obtain a material having an efficient heat sealing property, it is particularly preferable to use a polyester spunbond having a melting point of 220 ° C. or more. Here, the efficient heat sealing property means that high-speed and stable heat sealing can be obtained.

In the present invention, besides spunbond,
A card and binder nonwoven fabric, a needle punched nonwoven fabric, a spun lace, or the like is also used, but a spun bond is preferably used from the viewpoints of form stability, economy, and the like. The basis weight of the non-woven fabric used is 5 g / m ² to 100 g.
/ M ² . If it is less than 5 g / m ² , sufficient mechanical strength may not be obtained.
If it exceeds g / m ² , heat sealing may not be performed efficiently.

Next, the layer A or the layer B and the layer C are bonded together by an adhesive and integrated. This bonding may be performed by an emulsion or the like, but it is efficient to perform bonding by a melt blown method using a hot melt resin, and is preferable in maintaining air permeability. Hot melt resins include vinyl acetate copolymer, polyolefin,
Various types such as polyamide type, polyester type, synthetic rubber type, polyurethane type and polyvinyl alcohol type are used. Hot melt resin coating amount is 1g / m
The range from ² to 50 g / m ² applies, but 3 g
/ From ^{m 2} to about 30 g / ^{m 2} is more preferable. 1g
/ M ² , there is a possibility that adhesion may be difficult.
If it exceeds 0 g / m ² , sufficient adhesion is possible, but there is a possibility that air permeability may be reduced or uneconomical.

The packaging material of the present invention bonded as described above has an air permeability of 5 cm ³ / cm ² / sec or less as measured by the JISL 1096A method and the Frazier method, Can be packed without leaking. If the packaging material of the present invention is folded so that the A layer is on the inside, or if two sheets of packaging material are overlapped so that the A layer is also on the inside and heated with a roll or a flat plate from the outside, so-called heat sealing is performed. The inner MBs adhere very well, and high-speed and stable heat sealing is possible.

Particularly, the packaging material according to the present invention obtained by using a spunbond made of polyethylene terephthalate having a melting point of 263 ° C., which is a typical example of polyester, has extremely stable heat sealability.

Example 1 Septon SEPS manufactured by Kuraray Co., Ltd., which is a block copolymer of olefin and styrene (flow starting temperature: about 9
0 ° C.) and heat calendered basis weight 60 g /
Melt blown non-woven fabric (A layer) having m ² and basis weight 20
Adhesion to a polyethylene terephthalate spunbond having a g / m ² (melting point: 263 ° C.) (C layer) using a hot melt resin [Dispomelt ME110E (SBS) manufactured by Nippon NS Co., Ltd.) as follows. did. First, the hot melt resin was melted, applied continuously at a rate of 7 g / m ² on the surface of the spun bond by a melt blow method, and the melt blown nonwoven fabric was laminated thereon and pressure-bonded.

The obtained laminate was 1.2 cm ³ / cm ² /
It has a permeability of 2 sec, two laminates are laminated with the melt blown nonwoven fabric side inside, and the four sides are sealed under a condition of a seal width of 5 mm and a bag size of 6 cm × 8 cm (contents: silica gel powder 2 g). When the bag was made by heat sealing, the heat sealing efficiency was extremely good. Also, leakage of the contents was extremely small.

Example 2 The melt blown nonwoven fabric used in Example 1 (having a basis weight of 20)
g / m ² septon meltblown nonwoven fabric) (layer A)
Then, a melt-blown nonwoven fabric (layer B) made of polypropylene having a basis weight of 15 g / m ² and an average fiber diameter of 3.2 μm was bonded to each other by a heat calender to obtain a laminate. Subsequently, the same polyethylene terephthalate spunbond (C layer) as in Example 1 was bonded to the polypropylene melt blown side of the laminate in the same manner as in Example 1.

The laminate thus obtained has an air permeability of 0.5 c.
m ³ / cm ² / sec, and two laminates were stacked with the Septon meltblown nonwoven fabric side as the inner side, and the bag was formed by heat sealing in the same manner as in Example 1. As a result, efficient and efficient heat sealing was achieved. . Bincho charcoal powder was used as the contents, but almost no leakage of the contents was observed.

[0023]

According to the present invention, it has become possible to provide a packaging material which is breathable, does not leak granular powder, and has an efficient heat sealing property.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) D04H 3/00 D04H 3/00 F 3/16 3/16 F term (Reference) 3E086 AD01 BA04 BA19 BB47 BB51 DA01 4F100 AK01A AK01C AK03B AK03J AK07 AK12 AK12J AK41C AK42 AK73G AL01 BA02 BA03 CB03 DG15A DG15B DG15C GB17 JA04A JA04C JB16A JD02 JL00 JL12 YY00 YY00A YY00C 4L047 AA14 AA21 AB02 BC03 BA12 BC02

Claims (4)

[Claims] 1. A melt-blown nonwoven fabric (layer A) comprising a thermoplastic synthetic resin having a flow start temperature of 125 ° C. or lower.
And a nonwoven fabric (C layer) made of a synthetic resin having a melting point of 200 ° C. or higher, which is integrated with an adhesive, and has a gas permeability of 55 cm ³ / cm ² / sec or less. Excellent granular powder packaging material. 2. The heat seal according to claim 1, wherein a polyolefin melt blown nonwoven fabric (B layer) is sandwiched between the A layer and the C layer, and the B layer and the C layer are integrated with an adhesive. Granular powder packaging material with excellent properties. 3. The granular powder packaging material according to claim 1, wherein the layer C is a polyester spunbond. 4. The material for granular powder packaging excellent in heat sealability according to claim 1, wherein the adhesive is a resin for hot melt.