JPH0515626B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The resin film (including synthetic paper) obtained by the method of the present invention has excellent printability in offset printing, gravure printing, etc. even in low temperature and low humidity conditions in winter.
This printed resin film is useful as posters, packaging films, and decorative paper. [Prior art] A water-soluble antistatic material such as polyethyleneimine, ethyleneimine adduct of polyamine polyamide, quaternary nitrogen-containing acrylic polymer, acrylamide polymer, ethyleneimine-ethylene urea copolymer, etc. is applied to the surface of the thermoplastic resin film. It is well known to improve the printability of resin films by coating and drying them (Japanese Patent Publication No. 53-6676), 57.
-48578, No. 52-30390, No. 59-27770, JP-A-48-96664). These resin films having a polymer resin layer containing an antistatic agent on the surface have excellent gravure printing, flexographic printing, and offset printing properties. However, although there are no problems in spring, summer, and autumn, printing manufacturers have pointed out that printing ink is difficult to transfer to the resin film in winter, when the temperature is low and humidity is low. In order to deal with this problem, the rolled resin film or the resin film that is cut into sheets after molding and stacked is stored in a room at a temperature of 35°C to 45°C for 3 weeks to 1 month. The reality is that the issue is being resolved. [Problem to be solved by the invention] The above storage improves the transfer of printing ink that has been humidified to the same conditions as the atmosphere over the entire surface of the sheet, but special storage equipment is required for long-term storage under such conditions. Not only is this necessary, but it is also inconvenient because it requires the film manufacturer and the printing company to perform test printing to check whether the stored resin film has good printability. [Specific means for solving the problem] In the present invention, the temperature and humidity conditions are controlled when winding a resin film having an antistatic layer, or when cutting a resin film into sheets and stacking and packaging the resin film. By doing so, it is possible to provide a resin film that can be shipped immediately and has good transfer of printing ink even when printed. In the present invention, applying an antistatic agent to the surface,
When winding up dried resin film in a room or cutting it and stacking it into sheets, if the room atmosphere is outside the conditions of temperature 20 to 45℃ and relative humidity 50% or more, use a humidity regulator, temperature Use at least one of the regulators to adjust the room atmosphere to a constant temperature and humidity atmosphere of 20 to 45°C and a relative humidity of 50% or more before winding or cutting. The present invention provides a method for cutting or winding a resin film, which is characterized by stacking the resin film in a sheet shape. Examples of the resin film include films made of thermoplastic resins such as polypropylene, polyethylene, polyethylene terephthalate, polyamide, polystyrene, polyvinyl chloride, and polycarbonate, and films made by stretching these. This resin film is made of calcium carbonate, clay,
It may contain fillers such as talc and titanium oxide, heat stabilizers, lubricants, dispersants, and the like. Antistatic agents to be applied to the surface of the resin film include polyethyleneimine, ethyleneimine adducts of polyamineamide, and
Examples include epichlorohydrin adducts of polyamine polyamides, quaternary nitrogen-containing acrylic polymers, acrylamide polymers, and ethylene-ethylene urea copolymers. These are ST-1000, ST-1100, ST-1200, ST from Mitsubishi Yuka Fine Co., Ltd.
It is sold under the product names -1300 and ST-3000, by BASF under the trade name Polymin SN, and by Deitpharkyrus under the trade name Kaimen 557H. These water-soluble antistatic polymers are applied as an aqueous solution with a solution concentration of 0.5 to 3% by weight, so that the resin solid content is 0.01 to 1.0 g/m ² by coating means such as roll, spray, or brush. is applied and dried. As shown in Fig. 1, the resin film A having a resin layer of an antistatic agent on its surface is equipped with humidity regulators 1, 1... for humidifying or dehumidifying, and a temperature regulator having both heating and cooling functions. A certain air conditioning equipment 2,
2... is supplied into the room 3 from the air curtain 4 side, and the sheet 6 is
They are cut into shapes, stacked, and then packaged. Air curtain 4 in room 3 in the factory building
The upper and side walls except for the sides are isolated from the outside air by insulation materials, glass plates, resin films, etc. 7, 7, etc., so that the temperature and humidity inside the room 3 can be efficiently adjusted. Although FIG. 1 describes an example in which the film is cut into sheets and packaged, when the film is rolled up and shipped, a winding machine is used in place of the knives 5, 5. Temperature and relative humidity in room 3 are 20-45℃, 50%
above, preferably within a constant temperature of 55-80%,
Humidity regulators 1, 1... and air conditioners 2, 2... are used to maintain constant humidity. If the film is cut, stacked and packaged or rolled and shipped without this condition, the printing ink will not transfer well to the film surface. If the atmosphere is not adjusted during film cutting or slitting, the environmental conditions often exceed the above conditions (temperature 20 to 45°C, relative humidity 50% or more), especially in winter, when printing ink. Metastasis is often particularly bad in winter. In the present invention, it is presumed that by actively adjusting the conditions of the air that comes into contact with the sheet, the arrangement of the antistatic agent layer is changed, and the surface condition is changed to be suitable for offset printing. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 (1) 80% by weight of polypropylene with a melt index (MI) of 0.8 is blended with 20% by weight of calcium carbonate with an average particle size of 1.5 microns (A), and after kneading in an extruder set at 270°C, a sheet is prepared. It was extruded into a shape and cooled with a cooling device to obtain a non-stretched sheet. This sheet was heated to 145°C and then stretched 5 times in the machine direction. (2) Mixture (B) of 50% by weight of polypropylene with MI4.0 and 50% by weight of calcium carbonate powder, and 50% by weight of polypropylene with MI4.0 and high-density polyethylene 8
% by weight and a mixture (C) of 42% by weight of calcium carbonate were melt-kneaded at 270°C using separate extruders, then each was fed to one die and laminated within the die, and then the above Both sides of the 5-fold longitudinally stretched sheet obtained in (1) were coextruded so that layer (C) was on the outside. Next, this five-layer laminate was heated to 185℃ and laterally
A five-layer film was obtained by stretching 7.5 times. (3) The front and back surfaces of this five-layer laminated film are treated with corona discharge, and the thickness of each film (C)/(B)/(A)/(B)/(C) is 3/17/40/17. A synthetic paper with a five-layer structure of /3 microns was obtained. After applying an aqueous coating solution having the composition shown in Table 1 to the front and back surfaces of this synthetic paper to a solid content of 0.05 g/m ² , the aqueous coating solution was dried with warm air at 60°C.
The material was then cut into sheets in a room controlled at 30°C and relative humidity of approximately 70% to produce synthetic paper for printing. Using offset printing ink "TSP-400" (product name) manufactured by Toyo Ink Manufacturing Co., Ltd. and an offset 4-color printing machine manufactured by Komori Printing Machinery Co., Ltd., 4 colors ( Offset printing (black, blue, red, yellow) was performed, and the ink transferability, ink adhesion, continuous offset printing performance, and synthetic paper feed/discharge performance were evaluated using the following methods. The results are shown in Table 1. The temperature inside the factory building was 12±3°C, and the relative humidity was approximately 40%. Similarly, 10 days and 1 month after cutting, another room in the building (temperature 14
Printability was also evaluated on synthetic paper stored at 40% relative humidity. Method for evaluating printing performance: [Ink transferability] The halftone dot area of each color was magnified using a magnifying glass (30x), and the halftone dot reproducibility was visually judged. Halftone dot reproduction rate: 100-75% Good (○) 75-50% Slightly poor (△) 50-0% Poor (×) [Ink adhesion] Adhesive tape "Cello Tape" manufactured by Nichiban Co., Ltd. (product name) was brought into close contact with the printed surface, quickly peeled off along the printed surface, and the degree of ink removal from the paper surface was visually determined. Ink residual rate: 100-95% Good (○) 95-80% Slightly poor (△) 80-0% Poor (×) [Continuous offset printing performance] After printing 5000 sheets continuously, the ink pile on the blanket and the blanket The whiteness was compared with the state before printing. In addition, for the printed matter, the halftone dot reproducibility was visually determined by comparing the printed matter immediately after printing started and that after continuous printing. Blanket condition: Same as before printing (○) Slightly different (△) Largely different (×) Examples 2-3, Comparative Examples 1-3 Room conditions during cutting, antistatic agent composition, and storage conditions The offset printability of the synthetic paper obtained was evaluated in the same manner as in Example 1 except that the environmental conditions of the building were changed as shown in Table 1. The results are shown in Table 1. The components of the antistatic agent are as follows. (a) Water-soluble polyacrylic antistatic polymer “ST-1100 ^* ” manufactured by Mitsubishi Yuka Co., Ltd. (b) Ethyleneimine adduct of polyamine polyamide (Polymin SN, manufactured by BASF) (c) Epichlorohydrin adduct of water-soluble polyamine polyamide (“Kaimen 557H”, manufactured by Deitzk-Hercules)

[Table] Example 4 Instead of cutting synthetic paper, winding,
This was stored in a room at a temperature of 20° C. and a relative humidity of 40% for one day, rewound and subjected to offset printing, and evaluated in the same manner as in Example 1. The offset printability of the synthetic paper was the same as in Example 1.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an apparatus implementing the invention. In the figure, A is an antistatic agent coated resin film, 1
is a humidity regulator, 2 is an air conditioner, 3 is a room, 4 is an air curtain, and 5 is a knife.

Claims (1)

[Claims] 1. When an antistatic agent is applied to the surface and the dried resin film is rolled up in a room or cut and stacked into sheets, the atmosphere in the room is such that the temperature is 20 to 45°C and the relative humidity is If the condition exceeds 50%, use at least one of a humidity controller and a temperature controller to adjust the room atmosphere to a temperature of 20 to 45°C and a relative humidity of 50%.
A method for cutting or winding a resin film, which is characterized in that it is adjusted to an atmosphere of a constant temperature and constant humidity and then wound or cut and stacked in a sheet form. 2. The method according to claim 1, wherein the antistatic agent is a quaternary nitrogen atom-containing acrylic polymer or polyethyleneimine.