JPS5811568Y2 - Plastitsu Kuita - Google Patents

Description

[Detailed description of the invention] This invention relates to a plastic plate whose surface is protected.

Plastic plates used for industrial purposes are made of materials such as polymethyl methacrylate, polyvinyl chloride, polystyrene, and polycarbonate, and their surfaces are easily scratched, so they are protected by pasting kraft paper, plastic film, etc.

However, not only does kraft paper lack water resistance, but when using a plastic board, the glue used to attach the kraft paper to the plastic board remains on the surface of the plastic board even after the kraft paper is removed. There are disadvantages such as interfering with surface processing and making the surface opaque.In addition, two methods are generally used to improve the adhesion of plastic films to plastic plates.One of them is Another method of applying glue to a plastic film is to oxidize the surface of the plastic film, but in the former case, the disadvantage is that the glue remains on the plastic plate when the plastic film is peeled off, and in the latter case, the plastic film The amount of low-molecular substances increases on the treated surface, and as a result, the above-mentioned low-molecular substances remain on the surface of the plastic plate after this protective plastic film is peeled off, making it difficult to process the plastic plate surface, such as printing, vacuum deposition, etc. If the adhesion is excessively increased due to changes over time, the plastic film may be difficult to peel off when the plastic plate is used.

In an attempt, the surface of the polyethylene film was oxidized and the polyethylene film was peeled off from the attached polymethyl methacrylate board, and the surface of the 1 m2 polymethyl methacrylate board was washed with 200 ml of benzene, and what was attached to the surface was washed with benzene. and the washing solution was washed under reduced pressure for 5 minutes.
Evaporate to dryness at 0°C, extract the residue with 5 ml of acetone at 40°C, use the filtrate after filtration as a test solution for thin layer chromatography, spot it on a 10 ml test solution on a silica gel plate, and then Normal hexane/ethyl ester (60:
40% by volume) and cyclohexane/benzene (60:
After the development, a 10% sulfuric acid solution containing 1% cerium sulfate was sprayed onto the plate, and the plate was baked at 150°C for 15 minutes. 0.75, low molecular oxidized polyethylene appears with a migration rate of 0.6 to 0.2.

Additionally, Nippon Unicar's polyethylene film (DFD)
Figure 1 shows the migration rates of A, which was treated with J6775) in air at 350 W using a level surface treatment machine, and B, which was treated under the same conditions but in a nitrogen stream instead of in air. As shown, B has a smaller amount of low molecular weight polyethylene remaining on the surface of the polymethyl methacrylate board,
Furthermore, in case A, low molecular weight polyethylene oxide was detected.

The purpose of this invention is to provide a plastic plate with a protected surface, which eliminates the above-mentioned drawbacks.

This idea uses a polymethyl methacrylate plate as a plastic plate that has a plastic film attached to its surface, and the film is peeled off before use, and the surface is sealed with an inert gas. The surface of the ethylene-vinyl acetate copolymer film, to which no substance has been added, is pressed together with the corona discharge-treated surface in a corona discharge chamber where the film is protected. It is on a plastic plate.

A method of surface treatment to prevent oxidation on the surface of a plastic film is to place the plastic film opposite a treatment roll placed in a sealed chamber filled with an inert gas such as nitrogen or carbon dioxide. There is a method in which the plastic film is passed between a corona discharge electrode and a method in which the surface of the plastic film is subjected to plasma treatment in a closed chamber as described above.

As shown in Figure 3, the film treated to prevent oxidation has excellent adhesion, is uniform, and has little variation, and is not affected by the humidity of the outside air, so its properties are always constant. It has the characteristics that you can obtain the following.

To give an example, FIG. 2 shows an ethylene film on the surface of a polymethyl methacrylate plate 1 heated to 40 to 80°C, which is sealed with an inert gas and without any substance added to the surface. The surface of a vinyl acetate copolymer film (hereinafter simply referred to as a copolymer film) is bonded by overlapping the corona discharge-treated surfaces and pressing the film entirely or partially with a press or a roll.

The heating temperature of the polymethyl methacrylate plate varies depending on the pressurizing pressure, time, type of film, and corona discharge treated charcoal. Even the above copolymer film containing 20% vinyl acetate was subjected to corona discharge treatment. It is possible to omit the heating process and apply the adhesive.

This example was subjected to corona discharge treatment in an inert gas, so when a plastic film is subjected to corona discharge treatment, the treated surface is oxidized, and as a result, it gains good adhesion. In this example, by performing corona discharge treatment in an inert gas atmosphere, it has an even better adhesion property than the one oxidized by corona discharge in air, with extremely less low molecular weight substances. .

The situation is shown in the material Nippon Unicar Co., Ltd.'s polyethylene (DF)
DJ-5505), the adhesion temperature was 140°C, and the adhesion strength to the acrylic board was shown in the table below (the unit of adhesion strength is g/
25mm width) and as shown in Figure 3.
Adhesive force when t Adhesive cuff when 0
15 15160
20 4025
0 30 60 Furthermore, there is little oxidation and cutting of molecules due to oxidation on the surface of the plastic film, and as a result, there is extremely little residual low molecular weight material that migrates from the film to the plastic board when it is peeled off during use after adhering to the plastic board. , resulting in the processing of plastic plates,
That is, it does not cause trouble in printing, vacuum deposition, etc., and does not change much over time, so it is extremely easy to handle when peeling.

Since this device has the above-mentioned structural functions, the surface is well protected under normal conditions, the plastic film for protecting the surface of the plastic plate can be easily peeled off during use, and a plastic plate with a fresh surface can always be supplied. can.

[Brief explanation of drawings]

Figure 1 is a comparison of the migration rate of low-molecular-weight polyethylene in polyethylene films treated with corona discharge in air and those treated with corona discharge in nitrogen, and Figure 2 shows the surface protected by this invention. FIG. 3 is a longitudinal cross-sectional view of an example of the plastic plate shown in FIG.

Claims (1)

[Scope of utility model registration request] A plastic plate 2 has a plastic film 1 attached to its surface and is used by peeling off the film 1 during use.The plastic plate is a polymethyl methacrylate plate, and its surface is separately sealed with an inert gas. The surface is protected by pressing the surface of an ethylene-vinyl acetate copolymer film, to which no substance has been added, with the corona discharge-treated surface in a corona discharge chamber. plastic plate.