JPH0370628B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flexible container with high weld peel strength obtained from a laminated sheet made of woven fabric (cloth) or nonwoven fabric laminated with ethylene resin made of drawn polyolefin resin yarn. It is. Conventionally, laminated sheets have been used as materials for flexible containers. For example, laminated sheets for running-type flexible containers are made by laminating polyester or nylon multifilament woven fabrics with polyvinyl chloride resin film, but these are expensive and limit the fields in which they can be used. It will be done. In addition, as a laminated sheet for a one-way type flexible container, a single uniaxially stretched high-density polyethylene fabric can be used as is, or a low-density polyethylene film of about 30 to 50 μm can be laminated to the uniaxially stretched fabric by heat treatment to improve moisture resistance. Applied laminated sheet (Utility Model Application Publication No. 54-45277)
Alternatively, a single uniaxially stretched polypropylene fabric is used as it is, or a laminated sheet is used in which polypropylene of about 30 to 50 μm is laminated to the uniaxially stretched fabric by heat treatment to impart moisture resistance. . However, such one-way type laminated sheets for flexible containers do not have the welding (fusion) properties of high-frequency welding sheets, so flexible containers are manufactured by sewing, and bags may be torn or partially cut from the seams. This is a practical problem because the contents tend to leak. In order to improve this drawback, we added ethylene to both sides of the fabric made of drawn polyethylene resin yarn.
A bag has been proposed in which a fused film of vinyl acetate copolymer or a laminated fused film of low-density polyethylene and ethylene/vinyl acetate copolymer are laminated, and then the ethylene/vinyl acetate copolymer films are fused together by high frequency. (Utility Model Application Publication No. 55-146234). This bag is highly moisture-proof. However, since the adhesive strength of the fused weld portion is low, it is not suitable for use as a container bag for large (heavy) items. The present invention solves these problems and provides a flexible container that is highly moisture-proof and has high weld strength.The present invention is capable of sealing laminated sheets together by high-frequency welding, and has at least the weld peel strength after sealing. It provides a flexible container with a width of 10Kg/3cm. That is, in the present invention, an anchor coating agent is applied to the front and back surfaces of a woven or nonwoven fabric made of drawn polyolefin resin yarn, and then a molten film of ethylene resin whose surface has been ozone-treated is applied to the ozone-treated surface. A flexible container with a peel strength of at least 10 kg/3 cm width at the welded welded part manufactured by high frequency welding of a laminated sheet obtained by compressing the nonwoven fabric facing the surface coated with an anchor coating agent. This is what we provide. The laminated sheet of material for the flexible container of the present invention is capable of high frequency welding and has improved weld peel strength during high frequency sealing to at least 10 kg/3 cm width, preferably 13 to 30 kg/3 cm width. . The woven or nonwoven fabric (hereinafter simply referred to as the "base material") made of drawn polyolefin resin yarn used as this laminated sheet may be polyethylene, polypropylene, ethylene/butene copolymer, or propylene/butene copolymer. ,ethylene·
A tape-shaped, monofilament-shaped,
It is a woven or nonwoven fabric made of fibers in various shapes such as multifilament. There is no particular limit to the strength of these base materials, but in order to use them for flexible containers, the tensile strength is 30 kg/
It is desirable that the width is 5 cm or more, preferably 50 to 600 kg/5 cm width, and more preferably 70 to 400 kg/5 cm width. Examples of the ethylene resin to be adhered and laminated to the above base material include low-density polyethylene, high-density polyethylene, ethylene/α-olefin copolymer (α-olefin includes propylene, butene-1,
hexene-1,4-methylpentene-1, octene-1, etc.), ethylene/vinyl ester copolymer (ethylene/vinyl acetate copolymer, etc.), ethylene/α,β-unsaturated carboxylic acid ester copolymer (copolymers of ethylene and methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, or butyl methacrylate, etc.), ethylene/α,β-unsaturated carboxylic acid copolymers (copolymers of ethylene and Acrylic acid, methacrylic acid,
Copolymers with ethyl acrylic acid, itaconic acid, maleic acid or fumaric acid, etc.), ethylene α, β
-Metal neutralized product of carboxylic acid copolymer (metal ions used as metal neutralized product include Na ⁺ , K ⁺ ,
Li ⁺ , Cu ⁺ , Mg ⁺⁺ , Ca ⁺⁺ , Fe ⁺⁺ , Zn ⁺⁺ , Al ⁺⁺⁺ ,
Fe ⁺⁺⁺ , etc.), and these can also be used as a mixture of two or more. Among these resins, ethylene/vinyl acetate copolymer (preferably vinyl acetate content 5 to 40% by weight), ethylene/ethyl acrylate copolymer (preferably ethyl acrylate content 5 to 40% by weight), ethylene/acrylic acid copolymer A metal neutralized product (preferably metal ions of Zn, Na, K, Ca, Mg) are preferred. The melt viscosity of these resins depends on the processing temperature.
There is no particular restriction as long as it can be processed at 120 to 290℃, but the melt index (190℃) is 0.5 to 200g/10 minutes,
More preferably, it is in the range of 1 to 50 g/10 minutes. These resins also include antioxidants such as butylated hydroxytoluene (BHT), slip agents such as higher fatty acid amide, antistatic agents or antifogging agents such as polyglycerol fatty acids, and antiblocking agents such as silicon oxide. , silicon oxide, titanium oxide, iron oxide,
Additives such as high-frequency welder suitability improvers such as carbon, other organic and inorganic pigments, and flame retardants, fillers and modifying materials for rubbers such as rosin, ethylene-propylene copolymer rubber, and polybutadiene rubber. It can be added as necessary. In this case, substances or amounts that excessively reduce adhesive strength should be avoided. These ethylene resins can be laminated on one or both sides of the base material, but it is generally preferable to laminate both sides when used for flexible containers. For high-frequency seals that are laminated only on the flat surface of the base material, ethylene resins are superimposed on each other and the weld peel strength is measured. The amount of ethylene resin to be coated or laminated and adhered to the above base material is usually 50 to 50 to
It is good to set it as 3000g/m ^<2> , preferably 70-1000g/m ^<2> , more preferably 90-500g/m ^<2> . In order to maintain the welder peel strength at 10 kg/3 cm width or more, it is necessary to improve the adhesive strength between the base material and the Niminate resin, and for this purpose, it is manufactured by the method shown below. (1) An anchor coating agent such as a modified polyolefin obtained by graft polymerization of polyethyleneimine, alkyl titanate, α,β-unsaturated carboxylic acid, etc., an isocyanate compound, polyurethane, etc. is applied to the base material, and the solvent is dried. Next, the above ethylene resin is heated through the T-die of the extruder at a temperature of
A method in which a molten film is formed by extrusion at 120 to 290°C, the molten film is treated with ozone, and then the treated surface is used as an adhesive surface to pressure-bond and laminate onto the surface of an anchor-coated base material. (2) Apply the specific anchor coating agent described below to the base material and dry the solvent. Next, the anchor-coated substrate surface was used as an adhesive surface, and a molten film of the above-mentioned ethylene resin was extruded from the T-die of an extruder at a resin temperature of 200°C to 290°C was applied to the substrate after ozone treatment. How to crimp laminate on a surface. As the specific anchor coating agent, (a) per 100 parts by weight of isocyanate compound (including polyurethane and urethane prepolymer),
10% by weight or more of an ethylene/vinyl acetate copolymer with a vinyl acetate content of 20 to 50 parts by weight, preferably
(b) 10 parts by weight or more of the cyclized rubber described below, preferably 30 to 200 parts by weight, per 100 parts by weight of the isocyanate compound.
Contains 200 parts by weight. (c) 10 parts by weight or more of an ethylene/vinyl acetate copolymer with a vinyl acetate content of 20 to 50% by weight, preferably 30 parts by weight, per 100 parts by weight of the isocyanate compound.
~200 parts by weight and 10 parts by weight or more, preferably 30 to 200 parts by weight of cyclized rubber. in a solvent such as toluene or ethyl acetate with a solid content of 1
Use a solution dissolved to ~20% by weight. The above-mentioned cyclized rubber is an isomer which is made by treating natural rubber or synthetic rubber with a certain oxidizing agent or by other appropriate treatment to reduce the degree of unsaturation of the rubber to 1/2 to 1/3 of the original rubber. It is the body. Some of these cyclized rubbers are listed in "Rubber Industry Handbook <Revised Edition>" published by the Japan Rubber Association, pages 644-648 (published on January 1, 1964). For example, rubber cyclized with stannic chloride is good. Furthermore, before carrying out the anchor coating treatments described in (1) and (2) above, it is preferable to subject the surface of the substrate to a corona discharge treatment in order to further improve the adhesion of the ethylene resin film to the substrate. The ethylene resin to be laminated can be extruded as a single phase using an extruder, but resin films having different vinyl acetate contents or filler contents can also be coextruded and then laminated to the base material. In addition to the above-mentioned methods, there are known methods such as dry lamination and calender lamination, but these methods may also be used to laminate. Example 1 As a base material, a uniaxially stretched flat yarn woven fabric of high-density polyethylene (yarn width 8 mm, thickness 26 μm,
Using 1700 denier, the number of implants is 14 vertically/inch x 14 horizontally, corona discharge treatment is applied to both sides (processing amount on one side, 30 Watts/ ^m2 ), and one side is coated with isocyanate anchor coating agent ( Nippon Soda Co., Ltd. trade name "TITABOND-104", an ethyl acetate solution containing 4% by weight of the active ingredient) was applied, and the solvent was removed using a dryer, followed by anchor coating treatment. Further, the opposite side was similarly anchor coated. Next, a mixture (laminate composition) of 90% by weight of ethylene-vinyl acetate copolymer with a melt flow rate of 15 g/min and a vinyl acetate content of 20% by weight and 10% by weight of TiO ₂ was transferred to an extrusion laminating device. The resin was extruded from the attached T-die at a temperature of 240°C to form a molten film. Next, the molten film is placed under the die 40 toward one side.
Ozone concentration 20g/ from the nozzle installed at the mm position
By blowing m ² of air at a rate of 300/hour,
One side of the molten film was treated with ozone. Using the ozone-treated surface of this molten film as an adhesive surface, it was crimped and laminated onto the previously anchor-coated flat yarn cloth using a crimping roll. The lamination speed at this time was 30 m/min, and the thickness of the laminated layer was 200 g/m ² . Next, the opposite side was laminated in the same way. A flexible container bag (1 ton bag) with external dimensions of 1080 mm square and 1550 mm height was created using the above laminated sheet using a high-frequency welder, and the contents (1 ton of resin pellets) were actually packed into the bag to a height of 1 m. A practical test was conducted by dropping the product from a location. In addition, weld peel strength with high-frequency sealing was measured. The results are shown in Table-1. Weld peel strength with high frequency seal is 10Kg/3
It was found that laminated sheets with a width of cm or more have excellent properties for use in flexible containers. Note that the high frequency weld peel strength was measured by the method shown below. (1) Welding device: TIV-270B (product name) manufactured by Takano Electric Co., Ltd., capacity 2.6kw, frequency 40.68M
Hz, mold used 30mm x 250mm = 750mm ² Weld time varies within the range of approximately 10 to 120 seconds depending on the test sample. (2) The weld peeling test piece used had a plan view as shown in Figure 1 and a side view as shown in Figure 2. The shaded area in FIGS. 1 and 2 is the high frequency weld bonding area. In addition, a, b, and c in the figure represent the dimensions of the test piece, and each is as follows. a: 30 mm b: 40 mm c: 120 mm (3) Strength measurement method Using an Instron type tensile tester, the maximum strength was measured at a tensile speed of 200 mm/min. Example 2 The base material was a uniaxially stretched flat yarn woven fabric of polypropylene (yarn width 6 mm, thickness 29μ, 1500 denier,
The same procedure as in Example 1 was carried out except that the number of implants was 15 vertically (15 vertically and 15 horizontally 15 per inch). The results of the flexible container drop test and welder peel strength are shown in Table 1. Example 3 The anchor coating treatment agent for the base material was prepared by adding an isocyanate-based anchor coating agent (trade name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.) and a cyclized rubber (trade name "Thermolite" manufactured by Seiko Kagaku Co., Ltd.) to ethyl acetate.
Everything was carried out in the same manner as in Example 1 except that the mixture was changed to a 5 wt% dissolved mixture. The results of the flexible container drop test and welder peel strength are shown in Table 1. Comparative Example 1 The same procedure as in Example 1 was carried out except that the anchor coating treatment of the base material and the ozone treatment of the laminate resin were not performed. The results of the flexible container drop test and welder peel strength are shown in Table 1. Comparative Example 2 The same procedure as in Example 2 was carried out except that the laminated resin was not subjected to ozone treatment. The results of the flexible container drop test and welder peel strength are shown in Table 1. Comparative Example 3 The same procedure as in Example 2 was carried out except that the anchor coating treatment of the base material and the ozone treatment of the laminate resin were not performed. The results of the flexible container drop test and welder peel strength are shown in Table 1. 【table】

[Brief explanation of drawings]

1 and 2 show the shape of a test piece for measuring weld peel strength, FIG. 1 is a plan view of the test piece, and FIG. 2 is a side view thereof.

Claims (1)

[Claims] 1 An anchor coating agent is applied to the front and back surfaces of a woven fabric or nonwoven fabric made of drawn polyolefin resin yarn, and then a molten film of ethylene resin whose surface has been ozone-treated is coated with the anchor coating agent on the ozone-treated surface. A flexible container manufactured by high-frequency welding of a laminated sheet obtained by pressure-bonding the nonwoven fabric facing each other and having a peel strength of at least 10 kg/3 cm width at the welded welded part.