JPH0328300B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for manufacturing bag-making materials. More specifically, the present invention relates to a method for manufacturing bag-making materials without using waste paper film.

Technical Background Traditionally, desiccants, oxygen scavengers, freshness-preserving agents, deodorizers, heat-generating agents, etc., act on specific parts of the air, and insect repellents, repellents, fragrances, etc. Laminated bodies with controlled air permeability to a desired degree are used as materials for sachets for packaging substances that volatilize chemicals to achieve specific effects.

The following are known as these breathable laminates.

(1) Non-woven fabric or paper is used as a substrate, heat-sealable resin is laminated using pressure coating technology, and ventilation holes are punched through the front and back in post-processing.

(2) Non-woven fabric or paper is used as a base material, and a heat-sealable resin film is laminated using dry lamination technology, with ventilation holes penetrating the front and back sides in post-processing.

(3) A heat-sealable perforated film with pre-perforated holes bonded by thermocompression to a base material of non-woven fabric or paper.

The ventilation holes in (1) and (2) above are usually formed by pricking with a needle or the like from the side of the nonwoven fabric, or by slitting by making discontinuous linear cuts from the side of the film. When a bag is made from a laminate provided with ventilation holes by these methods, there is a drawback that the contents leak out and the surrounding area gets dirty. Also
Method (3) causes wrinkles and deformation of the holes due to the elongation of the perforated film during thermocompression bonding, so bag making materials with the desired air permeability can be manufactured at a speed that is practical. The disadvantage is that it cannot be done.

PRIOR ART Recently, a plastic film (abbreviated as porous film material in this book), which has a large number of fine through-holes on the front and back surfaces over the entire plane, has been developed and is being used for applications that require breathability. Summer. When using such a porous film material as a material for a breathable pouch, it is necessary to laminate it with other materials for the following reasons.

(1) Many porous film materials themselves do not have heat-sealing properties, and even if they do, they are insufficient for use in filling bag-making machines, so they must be laminated with a material that has good heat-sealing properties.

(2) Depending on the application, the material strength of the porous film material itself may not be sufficient to provide practical strength for the pouch, and reinforcing materials and lamination may be required.

When using films that do not inherently have air permeability as materials for heat sealing or reinforcing, it is necessary to make through holes only in these materials by some method. This is because if holes of the same size are made in a porous film material, the contents will leak out as described above.

Therefore, it is necessary to first make holes in these materials or a laminate thereof to form a perforated film material, and then bond this to a porous film material. That is, this is lamination of a perforated film material and a porous film material. By adjusting the shape, size, distribution, etc. of the pores in the perforated film material, it is possible to obtain a bag-making material in which the amount of ventilation is controlled to a desired degree.

The thermocompression bonding method mentioned above (3) is a method for bonding perforated film materials and porous film materials, but as with nonwoven fabrics and paper, wrinkles and holes may occur due to the stretching of the perforated film materials. This has the disadvantage that bag-making materials with high air permeability cannot be manufactured at a speed that is practical.

Furthermore, a dry lamination method is a well-known method for laminating non-porous films and nonwoven fabrics. This general mechanism involves applying the adhesive to a non-porous film in the coating section using the gravure method or three reverse roll method, evaporating the solvent in the coating liquid in the drying section, and then feeding it separately in the laminating section. After bonding the adhesive with a nonwoven fabric, etc., and rolling it up, the adhesive is left for a certain curing time to harden.

However, when a dry lamination method with such a general mechanism is used to bond a perforated film material and a porous film material, the adhesive on the applicator roll passes through the pores of the perforated film material. The adhesive transfers to the back-up roll, and as it rotates, it transfers again to the back side of the perforated film material, and after lamination, the bag-making material that is wound up on the roll hardens. This has the disadvantage of causing a so-called blocking phenomenon.

As a method to prevent this blocking phenomenon, a gravure plate roll is used that applies adhesive to the perforated film material, avoiding the perforated areas.
So-called pattern coating is considered, but in order to prevent the adhesive from running behind the hole, it is necessary to set the registration accuracy range to the size of the hole diameter plus the non-image area (adhesive-free area). The adhesive does not stick and the film becomes a raised laminate.
In addition, it is difficult to deal with roll stains that occur during the initial processing or during misregistration, and
Current dry laminators usually have various problems such as not being equipped with a registration adjustment mechanism.
This method is difficult to implement.

It is also possible to clean the adhesive that has passed through the holes in the perforated film material and transferred to the back-up roll while the roll rotates once, but it is not possible to effectively clean this roll in a narrow space. The method is still unknown.

The inventors first brought a waste paper film into contact with one side of the perforated film material, applied an adhesive solution to the other side of the perforated film material, then dried the adhesive solution, and applied the waste paper film to one side of the perforated film material. We proposed a method for producing a breathable bag-making material without any problems by removing the film and press-bonding a porous film material to an adhesive layer (Japanese Patent Laid-Open No. 167-1982).

Purpose of the Invention The inventors conducted research to further improve the above invention, and as a result, they arrived at the present invention. That is, an object of the present invention is to develop a method for bonding a porous film and a perforated film with an adhesive without using a waste paper film.

Structure of the Invention The present invention provides a porous film having a matrix of polyolefin or/and a derivative thereof;
A method for producing a breathable bag-making material, which comprises laminating with an adhesive a perforated film containing a layer containing polyolefin or/and its derivative and having pores with an equivalent diameter of 1.5 mm or less. It is.

The details of the configuration of the present invention will be explained below.

(Breathable bag-making material) The attached FIGS. 1 to 3 are cross-sectional views of the bag-making material produced by the method of the present invention.

In FIG. 1, 1 is a porous film material, 2 is a perforated film material, 3 is an adhesive, and 4 is a hole. That is, FIG. 1 shows a case where a film having heat-sealability is used alone as the perforated film material.

FIG. 2 shows a case in which a reinforcing film 5 and a heat-sealing film 6 are laminated and holes are formed to form a perforated film material.

FIG. 3 shows a case in which a reinforcing film and a heat-sealing film are formed into one film by co-extrusion, and holes are formed in this film to form a perforated film material 2'.

(Porous film material) The porous film material used in the present invention has an equivalent diameter determined by the air-methanol maximum bubble pressure method, which is usually 50μ or less, preferably 30μ.
It has a large number of through holes as shown below. In the present invention, the equivalent diameter is defined as the diameter of a circle with an area equal to the area of the hole.

The porous film material mentioned here is one made by laminating polyolefin resin fibers such as polyethylene, polypropylene, polybutylene, etc. in a random manner and bonding them by heating and pressing, or a similar polyolefin resin with calcium carbonate, silicon dioxide, etc.
These include those in which inorganic powder such as aluminum oxide is dispersed and then extruded into a sheet, or those in which these sheet-like materials are treated with an acid for stretching.

Typical examples of porous film materials include Tyvetsu (manufactured by Dupont, USA), NF sheet (manufactured by Tokuyama Soda), and Cellpore (manufactured by Sekisui Chemical).
etc. are generally commercially available and suitable.

(Perforated film material) The perforated film material used in the present invention has pores with a larger area than the micropores of the porous film material, and has a thickness of about 15 to 150 microns. There are no particular restrictions on the shape, but examples include circular, oval, and square shapes, and the hole size is 1.5 mm or less in equivalent diameter.

The hole size cannot exceed an equivalent diameter of 1.5mm. This is because if a perforated film with pores with an equivalent diameter exceeding 1.5 mm is used, when the adhesive solution is applied to the film, the adhesive solution will pass through the pores and adhere to the surface of the back-up roll. This is because the adhesive solution adhering to the roll transfers to the surface of the perforated film that should be clean, degrading the quality of the bag-making material.

There are no particular restrictions on the material for the perforated film material as long as it has good heat-sealing properties, but examples include polyolefins such as polyethylene and polypropylene, copolymers of ethylene and vinyl acetate (hereinafter abbreviated as EVA), and ionomers. Single-layer films such as or multi-layer films of these are used, and when particularly strong strength is required, for example, stretched films such as polypropylene, polyethylene terephthalate, nylon, and films with good heat sealability such as polyethylene, EVA, and ionomers are used. A layered structure is used.

(Adhesive) The adhesive used in the present invention may be any adhesive that can sufficiently bond a porous film material and a perforated film material, such as acrylic resin, vinyl acetate resin, ethylene-vinyl acetate copolymer, etc. Among these adhesives, two-component urethane adhesives with excellent room temperature curability, heat resistance, and flexibility are particularly preferred. To obtain sufficient adhesion,
The appropriate amount of adhesive applied to the perforated film is about 5 to 8 g/m ² in terms of solid content. Adhesives are diluted with a solvent such as ethyl acetate to a solid content of 26 to 40%, and the viscosity is adjusted to 10 to 25 seconds at 30°C using the Zankup (No. 3) method. is used at a liquid temperature of about 20 to 35℃. If the viscosity measurement is less than 10 seconds, the adhesive passes through the pores of the perforated film material and adheres to the surface of the back-up roll, and as the back-up roll rotates, the adhesive cleans the perforated film. When the adhesive is transferred to the desired surface and the bag-making material is rolled up, this adhesive causes a blocking phenomenon. Furthermore, if the measured viscosity exceeds 25 seconds, uneven coating may occur, or the amount of coating may be too large, causing adhesive to leak from around the pores of the porous film material when bonding to the porous film material. This causes inconveniences such as oozing out and blocking the micropores of the porous film.

(Manufacturing equipment) In order to carry out the manufacturing method of the present invention, a commonly used dry laminating equipment can be used, but the linear pressure between the application roll and the back up roll is about 3 to 7 kg/cm. The paper feeding speed is usually 30 to 150 m/min.

Examples Examples are shown below to explain the present invention in more detail, but the following examples are not intended to limit the present invention.

Example 1 A urethane anchoring agent (AD527 manufactured by Toyo Morton Co., Ltd.) was applied to a 12 micron thick polyethylene terephthalate film (ESPET#12 manufactured by Toyobo Co., Ltd.)
Coating using gravure method (150 screen lines/
inch, plate depth 40 microns), extrusion coated polyethylene (Sumikasen L705 manufactured by Sumitomo Chemical Co., Ltd.) to a thickness of 13 microns, and then coated with ionomer resin (Himilan AM6004 manufactured by Mitsui Polychemicals Co., Ltd.) for 25 microns.
A multilayer film with a width of 500 mm coated by micron extrusion was used as the raw material for the perforated film material. A continuous pattern of circular holes with a diameter of 0.7 mm was punched out on one side of this original film at intervals of 10 mm x 10 mm vertically and horizontally using a continuous punching machine to obtain a perforated film material. While feeding this perforated film material alone (without using waste paper film) into the coating section of a dry laminator, we diluted it with ethyl acetate.
A two-component urethane curing adhesive (Toyo Morton Co., Ltd.) with a viscosity adjusted to 15 seconds (30% solids)
Co., Ltd. BHS6020 (A + B liquid)) at a liquid temperature of 28±2℃,
Gravure method (screen line count 150 lines/inch,
Plate depth: 40 microns) Coated with a linear pressure of 4.88 kg/cm between back-up roll and gravure roll, passed through the drying section, and then separately fed paper with a width of 550 mm and a thickness of
120 micron porous film material (Tokuyama Soda Co., Ltd.)
It was bonded to NF-120-6) manufactured by Co., Ltd. at the bonding part. This laminate was left in a curing room at 40°C for 24 hours and then finished with slits.

In this example, the paper feed speed is 80 m/min and the width is 440 mm.
A material for bag making with a length of 8,000 m and a length of 8,000 m was manufactured in a continuous manner without any problems.

Comparative example A urethane anchoring agent (AD527, manufactured by Toyo Morton Co., Ltd.) was coated on a 12 micron thick polyethylene terephthalate film (ESPET#12, manufactured by Toyobo Co., Ltd.) using the gravure method (screen line count: 150 lines/inch). , a plate depth of 40 microns), extruded and coated 13 microns of polyethylene (Sumikasen L705 manufactured by Sumitomo Chemical Co., Ltd.), and then extruded and coated 25 microns of ionomer resin (Himilan AM6004 manufactured by Mitsui Polychemicals) on top of that. The resulting multilayer film with a width of 500 mm was used as a raw material for perforated film material.

A continuous punching machine punched out circular holes with a diameter of 2.0 mm in a continuous pattern with an interval of 15 mm x 15 mm vertically and horizontally on one side of this original film, thereby producing a perforated film material.

By diluting this perforated film material with ethyl acetate while continuously feeding it into the coating section of a dry laminator at a speed of 80 m/min, the viscosity of Zankup No. 3 (30°C) was reduced to 15 seconds ( solid content 30%)
A urethane-based two-component curing adhesive [BHS6020 (A + B liquid) manufactured by Toyo Morton Co., Ltd.] adjusted to
Gravure method (screen line count 150 lines/inch, plate depth 40 microns, linear pressure between back-up roll and gravure roll 4.88 Kg/cm) at a liquid temperature of 28±2°C.
After passing through a drying section, it is laminated with a separately fed porous film (NF-120-6 manufactured by Tokuyama Soda Co., Ltd.) with a width of 550 mm and a thickness of 120 microns. did. In this case, the adhesive on the applicator roll passes through the holes in the perforated film material and is transferred to the back-up roll, and as this roll rotates, it is transferred again to the back side of the perforated film material, and the adhesive is transferred to the backside of the perforated film material. Significant staining occurred on each roll that came into contact with the In addition, when the bag-making material wound into a roll after lamination was left in a curing room at 40°C for 24 hours, the re-transferred adhesive hardened, causing a so-called blocking phenomenon, which caused the slit to fail. Finishing processing was not possible.

Application Example On the other hand, a non-breathable laminated film was prepared by extrusion coating 40 g/m ² of nylon Fupanbond nonwoven fabric manufactured by Asahi Kasei Co., Ltd. with 30 microns of polyethylene and 20 microns of ionomer, followed by slit finishing.

The bag-making material obtained in Example 1 and the above-mentioned non-breathable laminated film were stacked so that the ionomer side faces faced each other, and the three peripheral sides were thermally bonded to form an effective area of 120× I made an 85mm bag. This bag contains 28 parts of iron powder, 8 parts of activated carbon, and water.
After filling the opening with 50 g of a composition that generates heat by reacting with oxygen in the air, which is a mixture of 10 parts of vermiculite, 3 parts of vermiculite, and 1 part of common salt, the opening was heat-sealed to form a heating element.
When the heating element obtained in this way was attached to the human body over a layer of underwear, a comfortable temperature of about 45°C was achieved at about 30°C.
Lasted for an hour. In addition, the contents do not clog the holes or leak to the outside, which tends to happen with bags in which through-holes are made on the front and back using needles, etc., due to post-processing of the laminate, and heat generation is stable. was.

(Effect of the invention) The effects of the present invention are listed below.

(1) No clogging or leakage of contents to the outside occurs in the holes, which tends to occur when through-holes are made on the front and back sides of the laminate in post-processing.

(2) There are no drawbacks such as wrinkles or hole deformation caused by thermocompression bonding.

(3) Since it is possible to obtain a bag-making material whose air permeability is freely controlled within a range that is lower than the air permeability inherent to porous films, it has a wide range of applications.

(4) Since adhesive bonding is used, the range of material selection is wider than with thermocompression bonding.

(5) Since waste paper film is not used, conventional dry laminating equipment can be used without modification.

(6) Process control is simple because no waste paper film is used.

(7) Since waste paper film is not used, material costs can be reduced.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views of a bag-making material produced by the method of the present invention. The symbols in the drawings represent the following. 1... Porous film material, 2... Perforated film material, 2'... Coextruded film, 3... Adhesive,
4... Holes of perforated film, 5... Reinforcing film, 6... Heat-sealable film.

Claims (1)

[Scope of Claims] 1. A film comprising a heat-sealing layer containing polyolefin or/and its derivative as a component, having an equivalent diameter of 1.5 mm or less, and having an area larger than the pores of the porous film material described below. The viscosity measured at 30℃ by Zankup (No. 3) method is 10~
Apply the adjusted adhesive solution for 25 seconds, and then overlay and paste a porous film material containing polyolefin or/and its derivatives as a matrix, which has many fine pores with an equivalent diameter of 50 μm or less, on the adhesive surface. 1. A method for producing a heat-sealable bag-making material having air permeability. 2 The perforated film material is polyolefin or/
2. The manufacturing method according to claim 1, wherein the manufacturing method is a single-layer heat-sealable film containing a compound or a derivative thereof as a component. 3. A patent claim characterized in that the perforated film material is a laminated multilayer film of heat-sealable films containing polyolefin and/or its derivatives, or of the heat-sealable film and another synthetic resin film. range 1
The manufacturing method described in section. 4. The manufacturing method according to any one of claims 1 to 3, wherein the adhesive is a two-component urethane adhesive.