JPH09228256A - Flexible container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flexible container of excellent thermal resistance and RF weldability by coating at least one surface of a base fabric with a thermoplastic resin film that contains ammonium polyphosphate. SOLUTION: This flexible container is obtained by mixing a thermoplastic resin that contains no halogen element, such as ethylene-vinyl acetate copolymer or olefin-based elastomer, whose thermal resistance (determined in accordance with Japanese Industrial Standard Z 1651) is higher than 80 deg.C, with ammonium polyphosphate shown by the formula ((n) is 50 or a larger integer), forming the mixture into a 80-300μm thick sheet by a T-die extrusion method, and laying and hot-pressing the sheet on at least one surface of a base fabric of plain- weave texture.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flexible container having excellent heat resistance and high-frequency bonding property.

[0002]

2. Description of the Related Art Conventionally, vinyl chloride resin is coated on a fiber cloth by various methods such as a calendering method, a coating method and a T-die extrusion method to produce tarpaulins, which are used in flexible containers. Vinyl chloride resin has advantages such as low cost, good handleability, and excellent high-frequency jointability in sewing flexible containers, but it has the serious drawback of releasing toxic gases and smoke containing halogen elements and residues during combustion. Therefore, from a global environmental scale, there is a strong demand for development of products made of a resin containing no halogen element for the purpose of environmental protection.

From such a viewpoint, a flexible container made of an olefin resin has been studied, and from the viewpoint of high-frequency bonding property, an ethylene / vinyl acetate copolymer has been adopted and used for transporting plastic pellets.

As the ethylene / vinyl acetate copolymer, a vinyl acetate component having a content of 19% by weight or more is used from the viewpoint of high-frequency bonding performance. Since the resin has a low softening temperature, it is 70 to 90 ° C. When the plastic pellets having the above temperature are added, there is a serious drawback that the pellets are heat fusion bonded to the surface of the container resin.

In order to solve such a problem, an olefin resin having a high softening temperature has been studied. However, since a resin having a high softening temperature deteriorates high frequency bonding property, a halogen element having both high frequency bonding property and heat resistance is used. A flexible container made of a thermoplastic resin that does not contain is desired.

[0006]

SUMMARY OF THE INVENTION The present invention provides a heat-resistant flexible container made of a thermoplastic resin having excellent high-frequency bonding property.

[0007]

The present invention has the following constitution in order to solve such problems. That is, the flexible container of the present invention is a flexible container in which at least one surface of a fiber base cloth is coated with a thermoplastic resin, and the thermoplastic resin is JIS Z-1651.
A heat-resistant temperature of 80 ° C. or higher measured by the method specified in 1
It is characterized by containing 5 to 30 parts by weight of ammonium polyphosphate represented by the following formula.

Embedded image

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention has been earnestly studied in view of the fact that a flexible container made of an ethylene / vinyl acetate copolymer is poor in heat resistance and its use is limited. It was clarified that high-frequency bondability can be improved while maintaining flexibility and physical strength of the resin by mixing a specific amount of ammonium polyphosphate with a thermoplastic resin having higher heat resistance than the vinyl copolymer.

The thermoplastic resin of the present invention means JIS Z-
There is no particular limitation as long as the heat resistance temperature defined in 1651 exceeds 80 ° C., and flexible olefin resins, polyester resins, polyacrylic resins, polyurethane resins, polyamide resins, etc. Although it can be used, an olefin resin is preferable from the viewpoints of easy disposal, incineration, and lightness.

The olefin resin of the present invention includes ethylene and butene-1 or hexene-1 or octene-
1 or 4 2 of α-olefin such as methylpentene-1
~ 15 wt% copolymerized ethylene / α-olefin copolymer, ethylene with alkyl acrylate 5-30 wt%
Mutual compatibility between copolymerized ethylene / alkyl acrylate copolymer and rubber component (soft segment) with rubber elasticity in polymer chain and crystalline or glassy component (hard segment) to prevent plastic deformation at room temperature For example, an olefin elastomer having both components may be used.

Specific examples of such olefin elastomers include Mirastomer (manufactured by Mitsui Petrochemical Industry Co., Ltd.), Santoprene (manufactured by AES Japan Co., Ltd.), Nisseki Soft Rex (manufactured by Nippon Petrochemical Co., Ltd.) and Oreflex. (Showa Denko KK), Sumiflex (Sumitomo Bakelite KK), Sumitomo TPE
(Sumitomo Chemical Co., Ltd.), Thermoran (Mitsubishi Chemical Co., Ltd.) and the like can be used, but are not limited thereto.

According to the present invention, a high-frequency weldability is imparted by mixing a specific amount of ammonium polyphosphate with an olefin resin having a heat-resistant temperature of more than 80 ° C. specified by JIS Z-1651.

The ammonium polyphosphate of the present invention is represented by the following formula, and the degree of polymerization n is a positive number of 50 or more, preferably 200 or more, more preferably 500 to 1000 in view of water resistance. It may be modified with melamine or an isocyanate compound, and specifically, Ex
Olit 422, 462 (made by Hoechst) and Sumisafe P (made by Sumitomo Chemical Co., Ltd.) can be used.

[0014]

Embedded image The mixing amount of the ammonium polyphosphate of the present invention is 5 to 30 parts by weight, preferably 10 to 25 parts by weight, based on 100 parts by weight of the olefin resin. If it is less than 5 parts by weight, the high-frequency welding performance may be insufficient, and if it exceeds 30 parts by weight, physical properties such as strength of the mixed resin sheet may be deteriorated. The mixing amount of ammonium polyphosphate of the present invention is
It may be determined according to the type of resin used and the intended high-frequency sewing property. A flame retardant, a stabilizer, an antistatic agent, a colorant, a filler and the like can be mixed with these resins.

The fiber base fabric of the present invention is a knitted or woven fabric composed of synthetic fibers such as polyester, polyamide and vinylon and natural fibers such as cotton and hemp, either alone or in combination, and the fibers are long fibers or short fibers. But it's okay. Among them, strength,
A woven fabric made of continuous polyester fibers is preferable in terms of dimensional stability. An adhesive for increasing the adhesiveness with the resin sheet may be added to the knitted fabric.

The method for producing the flexible container having excellent heat resistance and high-frequency welding property of the present invention is not particularly limited, and an ordinary method can be adopted. For example, the thermoplastic resin and ammonium polyphosphate are uniformly mixed. 80 to 30 by mixing the mixture into a calender method or T-die extrusion method.
It can be produced by thermocompressing a sheet having a thickness of 0 micron on both sides of the fiber base fabric.

[0017]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The performance values shown in Examples and Comparative Examples were measured by the following methods. (Heat resistance) By the method specified in JIS Z-1651, sheets of 2 cm wide and 3 cm long sheets are superposed on each other, sandwiched between two 5 cm x 5 cm smooth glass plates, and a load of 1 kg is applied. After changing the temperature in a constant temperature dryer for 1 hour and then taking it out, immediately remove the two sheets and check for any abnormalities such as surface adhesion, cracks, damage, peeling of the coating, etc. Was set as the heat resistant temperature.

(High-frequency welding) Using a high-frequency welder YF7000A type device manufactured by Yamamoto Vinita Co., Ltd., a bonding process was performed with an anode current value of 1 A, a pressing pressure of 3 kg / cm ² , a welding time of 8 seconds, and a cooling time of 3 seconds. The peel strength of 3 cm width in the vertical direction is measured by the method specified in K 6328 and Kg.
displayed. (Tensile Strength of Sheet) The tensile strength in the vertical direction of a 230-micron-thick sheet molded by T-die extrusion is measured by the method specified in JIS K 6730, and the strength retention rate for a sheet not containing ammonium polyphosphate is calculated. did.

Examples 1 to 9 and Comparative Examples 1 to 3 Ammonium polyphosphate was mixed with a resin containing the following blue pigment, antioxidant and the like, and 230 was prepared by a T-die extrusion method.
Molded micron-thick sheet, 750 denier, 96
A plain woven fabric in which polyester fibers (made by Toray Industries, Inc.) of filaments are used for warp and weft (vertical yarn density 21 /
Inch, weft density 20 threads / inch, thickness 320 microns) were thermocompression bonded to both sides to obtain a flexible container having a thickness of 730 microns. Table 1 shows the performance of the flexible container.

(Type of Resin) a. Ethylene / vinyl acetate copolymer (Evatate CV2097 manufactured by Sumitomo Chemical Co., Ltd.) b. Ethylene / α-olefin copolymer (Sumikasen VL100 manufactured by Sumitomo Chemical Co., Ltd.) c. Olefin elastomer (Mitsui Petrochemical Co., Ltd. Mirastomer 7030) d. Ammonium polyphosphate (Hohlist Exoli
t422)

[Table 1] It can be seen from Table 1 that the resin sheet according to the present invention has a small decrease in strength of the resin sheet and has both heat resistance and high-frequency bondability.

[0021]

According to the present invention, a flexible container having excellent heat resistance and high-frequency bonding property can be stably supplied.

Claims (7)

[Claims] 1. A flexible container in which at least one side of a fiber base cloth is coated with a thermoplastic resin, the thermoplastic resin having a heat resistance temperature of more than 80 ° C. measured by a method specified in JIS Z-1651. A flexible container which is a thermoplastic resin containing no elements and which contains 5 to 30 parts by weight of ammonium polyphosphate represented by the following formula. Embedded image 2. The flexible container according to claim 1, wherein the thermoplastic resin is an olefin resin. 3. The flexible container according to claim 1, wherein the coating is formed by thermocompression bonding. 4. The flexible container according to claim 1, wherein the coating is a thermoplastic resin coating having a thickness of 80 to 300 μm. 5. The flexible container according to claim 1, wherein the fiber base fabric is a woven fabric. 6. The flexible container according to claim 1, wherein the fiber base fabric is composed of long fibers. 7. The flexible container according to claim 1, wherein the fiber base cloth is composed of polyester fibers.