JPS5928168B2 - Method for producing thermoplastic synthetic resin film with improved surface properties or air permeability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a thermoplastic synthetic resin film with improved surface properties such as lubricity, air permeability, or liquid permeability.

Methods for improving the surface properties of thermoplastic synthetic resin films include adding a lubricant and roughening the surface with an abrasive.
Alternatively, there is a method such as corona discharge treatment.

These purposes include (V) (corona discharge treatment) to improve adhesion in lamination or printing, and to improve the lubricity of the film surface and prevent adhesion (addition of lubricant, surface polishing). Mechanical methods such as surface polishing have the disadvantage of significantly reducing the tensile strength of the thermoplastic synthetic resin film, and the surface scratches only result in extremely uneven shapes. Electrical treatment methods can improve adhesion, but they can also improve the film's slipperiness or prevent adhesion (films adhering to each other).
etc. had little effect. In addition, the method of adding inorganic powder such as calcium carbonate to the film itself involves blending it into the polymer or coating it on the film, but it is difficult to process only arbitrary parts, and it is difficult to add inorganic powder such as lubricant to the film material. There was also a risk that other properties would deteriorate due to the introduction of foreign substances. In addition, in order to increase the air permeability or liquid permeability of the thermoplastic synthetic resin film,
Conventionally, methods such as punching a small hole D and applying a heated steel needle to melt and perforate the hole have been practiced. These holes are mechanically drilled, so the hole diameter is several times, and lw
It was extremely difficult to drill micropores smaller than rm. In addition, in the case of melt-drilled holes, the roundness of the holes was bulged up by the molten resin, resulting in poor appearance.D, in the case of holes made by simply punching, the tensile strength was significantly deteriorated. The present invention solves the shortcomings of these conventional improved films, and also provides 1. The present invention provides a method for producing a thermoplastic synthetic resin film in which a fine rough surface or fine pores are provided using a near-infrared flash irradiation method that contains almost no wavelengths of 5μ or more, and the film can be used for taking out various household wrapping films. anti-sticking, electrochemical separators for batteries, various filters, gas or liquid passage control materials, smokable packaging films for salami sausages, decorative films, adhesive-improved films, erasable films, etc. It can be used for many purposes.

The method for producing the film according to the present invention is to coat a thermoplastic synthetic resin film (hereinafter referred to as 1.
A flash of high-intensity near-infrared rays containing almost no wavelengths of 5μ or more is irradiated, and the heat generated by the heating element melts and shrinks the part of the film that corresponds to the heating element and roughens the surface, or causes the film to melt and shrink. As a result, fine pores are formed.

The present invention is capable of adjusting the size of irregularities on a finely rough surface or the size and formation density of fine pores by the size and density of the halftone printed part (heating element) of the infrared absorption and exothermic substance of the heating element. I can do it. In addition, when producing the film of the present invention, the adjustment of whether to roughen the film surface or form a fine dimension L depends on the characteristics of the raw film (softening point, heat shrinkage rate, thickness, etc.) It can be arbitrarily changed depending on the heat generation efficiency of the heating element, the intensity of irradiation energy, etc. ′j That is, if the material film and heating element are constant,
In the case of relatively low energy, the surface of the film is only roughened, but as the irradiation energy becomes stronger, the depth of the depressions in the roughened portion increases as the thickness of the b1 film increases. When reached, a small hole is formed. The film used in the present invention is preferably a thermoplastic synthetic resin film that is stretched and oriented and has heat shrinkability, and preferably has a thickness of 150 μm or less.

Regarding heat shrinkability, it is necessary that the thermoplastic synthetic resin exhibits a heat shrinkage rate of 10% or more in both the longitudinal and transverse directions at the softening point temperature. It has been found that the higher the thermal contraction rate, the less energy is required to form a finely rough surface or fine pores. In addition, the thermoplastic synthetic resin used in the present invention includes:
Polystyrene, polyester, polycarbonate, vinyl chloride resin, vinyl acetate resin, ethylene vinyl acetate copolymer resin, polyethylene, polypropylene, fluororesin, polyamide resin, acetal resin, cellulose plastic, vinylidene chloride monovinyl chloride copolymer Examples include resin, acrylic resin, ABS resin, etc. T-die method (stretching)
A material made into a film by an inflation method or the like is used as a raw material film. The heating element, which converts light energy into thermal energy and roughens the surface of the material film or forms small holes, is made by adding ink or paint containing a substance such as carbon black that absorbs light and converts it into heat on paper, glass, etc. A support made of aluminum, stainless steel, etc., printed with halftone dots or a mesh pattern is used.

The mesh printing referred to here refers to printing in which countless minute dots are printed like halftone dots, and the shape of the dots is nine squares, stars, etc.
It can be any shape, such as a triangle, but the size is smaller than the diameter,
Preferably, it is 2 wfL to 0.05 Tm, and the area ratio of the non-printed portion is preferably set to 20% or more, preferably 40 to 70%. In addition, only when the surface of the material film is roughened, a width of 0.05 to 2
It is also possible to use a heating element (mesh-like) in which the lines of rw1 are arranged in an infinite number of ways (vertically and horizontally or in one direction) with appropriate spacing between them. Even if the size of this heating element is too large or too small,
Alternatively, if the space in the non-printing area is too small, the heat generated by constant irradiation energy will be dispersed, resulting in insufficient roughening of the film surface or formation of small holes. Furthermore, if there are too many spaces in the non-printing area, the obtained rough surface effect or the air permeability effect due to the fine pores will be weakened. The support for this heating element can be of any shape depending on the method of near-infrared flash irradiation, such as paper, glass or metal plates, cylinders, or rolls as described above. In addition, carbon black, which is the main material of this heating element, is mixed with a solid material such as resin to make printing ink or paint, and is then printed using various methods such as screen printing, baking painting, gravure printing, and offset printing.
It can be provided on the support. In addition, the light source used for irradiation does not include a light source with a relatively long wavelength that is absorbed by paper, metal, glass, etc. and generates heat.
Most preferred is an electron discharge tube filled with xenon gas, which hardly contains wavelengths of μ or more.

The energy of this light source varies depending on the material film and the intended use, but an intensity of 2.5 to 7.5 W seconds/1 is used. The table below shows the results of measuring the -IL physical properties of the film in which microscopic pores were formed according to the present invention.

(1) Sample Samples 1 to 3 were prepared using the following film, heating element, and irradiation light source.

Film: Vinylidene chloride-vinyl chloride copolymer film, thickness 20μ, heating element: black offset 150 lines, halftone dot print and 100 line halftone dot print irradiation light source; Thermal copying machine using Xenon electron discharge tube (trade name Xenofax, manufactured by Riso Kagaku Kogyo Co., Ltd.) Sample Jf6. 1 is a blank, a raw film, Haruka 2 is a 150-mesh dot heating element and one side of the film is irradiated, and Haruka 3 is a 100-mesh dot heating element and one side of the film is irradiated.

(2) Results of measurement of physical properties of samples The improved film according to the present invention has improved air permeability due to the fine pores as described above.

Furthermore, due to the formation of minute pores, a slight bulge D (20% to 30%) was observed at the periphery of the pores, but there was almost no change in dimensions compared to the raw film. Furthermore, although the raw material film has extremely high adhesion, the adhesion of the film of the present invention, which has been improved in processing, has deteriorated. In order to improve the tensile D strength of the film of the present invention, it is possible to use a material film laminated with synthetic fiber gauze.

Furthermore, the film according to the present invention can also be produced by directly providing a heating substance on the surface of a raw material film by printing or the like and then irradiating it with light. In addition, if heating elements are arranged in various patterns (in this area, they must be arranged in a mesh pattern),
It is also possible to make only the portion that corresponds to the pattern of the heating element into a frosted glass-like rough surface film, which can be used for purposes such as a decorative film or a partial filter.

Furthermore, if the thermoplastic synthetic resin film of the present invention having minute pores formed therein is placed under tension on the printing screen of a rotary printing machine used in stencil printing, and a stencil printing base paper is pasted on top of the printing screen, printing can be carried out. , the amount of printing ink supplied can be saved to an appropriate amount, and blurring of printed matter due to overflow of printing ink can be prevented.

Examples will be described below.

Example 1 A biaxially stretched poly-9 ester (po-9 ethylene terephthalate) film with a thickness of 5 μm and a heating element of 100 meshes (1 inch per square b, 100×100) were placed in a square space with a non-printing area ratio of 50%. Offset print containing carbon (printed as dots) (high quality paper, A4 size)
A thermal copying machine using a xenon electronic flash discharge tube (trade name: Xenofax, manufactured by Riso Kagaku Kogyo Co., Ltd., irradiation energy approximately 2.5 W seconds/Cd)
17~8/1000 second irradiation) Yota, 1 side is approximately 0.12
Square-shaped holes were formed (perforation density approximately 45%).

When this was used as an industrial filtration material, the purpose could be separated. Example 2 A vinylidene chloride monovinyl chloride copolymer resin film with a thickness of 20 μm produced by the inflation method was similarly produced using the same heating element (offset printed material) and thermal copying machine as used in Example 1. Microscopic holes were formed on the film.

This is made into a bag with a fold width of 50m and a length of 2507mm using a high frequency bag making machine.
The bag is made into a tube-shaped pouch of size 1.5 m, filled with meat paste for salami sausage, and subjected to the normal smoking process. was gotten. Example 3 A 65 mesh mesh (cotton cloth 0.2Tm) was placed on the surface of an aluminum roller with a diameter of 80Tm and a length of 300W1n.
A heating element was formed by screen printing and baking with a melamine resin paint containing 60% carbon black.

This heating element roller is attached to the winder of wrap film for household food packaging, and a xenon electron discharge tube irradiation device (irradiation energy of approximately 3
W seconds/Cd, irradiation at 1 second intervals) was installed. Using this winder, a polyethylene film with a width of 300m and a thickness of 12μ with good adhesion (films are in close contact with each other) is wound onto a paper tube of approximately 40WI in diameter to 20M. The film (on the inside of the roll) was passed through the heating roller soil and irradiated with light in flashes five times at 1 second intervals (irradiation time approximately 6/1000 seconds). In addition, the moving speed of the film is approximately 1 cm/cm just before it stops.
In seconds, an uneven mesh-like rough surface with depressions (about 4 μm) corresponding to the mesh heating elements was formed on the film over a length of about 5 cm. When this rough surface part is cut at the end and wound up on a paper tube, the end part becomes a rough surface, so the rough surface part completely loses the adhesion of the film and the b1 wrap film cannot be unrolled. The edges were clear and the film was easy to unwind. Conventionally, when unwinding this type of adhesive wrap film, the ends of the unwinding were difficult to distinguish because the films were in close contact with each other, and colored zero-adhesive tape or the like was pasted to mark the unwinding, and the film had to be removed before being removed. was, but
There is no need to attach these tapes, and the initial unrolling work has become easier. Example 4 A vinylidene chloride monovinyl chloride copolymer resin film with a thickness of 20 μm produced by the inflation method was produced in the same manner as in Example 1 using the same heating element (offset printed material) and thermal copying machine. A small hole was formed on the top.

Claims (1)

[Scope of Claims] 1. A heating element made of an infrared absorbing material arranged in a dot or mesh pattern and a thermoplastic synthetic resin film are superimposed, and a xenon gas-filled electron tube is used to emit wavelengths of 1.5μ or more. 1. A method for producing a thermoplastic synthetic resin film, which comprises irradiating a flash of high-intensity near-infrared rays that contain almost no part of the film to make the surface of the film that corresponds to the heating element finely roughened or to form fine pores. 2. The method according to claim 1, which uses ink or paint to which carbon black is added as the infrared absorbing substance. 3. A patent claim that uses, as a heating element, an ink or paint containing carbon black printed on a paper, glass, or metal plate, cylinder, or roll-shaped support in the form of halftone dots or a mesh. The method described in item 1.