KR20200057203A - method of manufacturing reflector sheet - Google Patents

Abstract

The present invention relates to a method for manufacturing a reflector sheet having a reflectance of 97% or more while significantly lowering the production cost. The method comprises a first step of performing vacuum thermal deposition on a substrate at a high speed where the production speed, or the moving speed of a film, is 300 to 500 m/min using aluminum and taking a deposition-completed film roll out of a vacuum chamber; and a second step of mounting the roll on silver (Ag) sputtering equipment and performing silver (Ag) sputtering on the surface of the aluminum vacuum thermal deposited film at a speed of 5 to 15 m/min to manufacture a reflector sheet.

Description

{Method of manufacturing reflector sheet}

The present invention relates to a method for manufacturing a reflective film by vapor deposition. That is, a polyethylene terephthalate (PET) film or other plastic film base material is vacuum-deposited or sputtered with a metallic material (Al, Ag, Zn, Cu, etc.) to increase the surface reflectance to produce a reflective sheet. It's about technology.

A method of depositing a coating material of a metallic material into a thin film on a plastic film substrate (adhesive) by a physical method includes thermal evaporation, sputtering, and the like. In the above methods, a coating layer is formed on the surface of the adherend with a thin film thickness of tens of angstroms or thousands of angstroms by evaporating the coating material inside the vacuum chamber to adhere to the surface of the adherend. According to the method of evaporating the coating material, it is divided into a thermal evaporation method and a sputtering method. The thermal evaporation method places the coating material and the adherend inside a vacuum chamber, and heats the entire mass of the coating material to evaporate the coating material in atomic or molecular state It is a method of coating the surface of the adherend with a film material by coating it on the surface of the adherend. On the other hand, sputtering does not heat the entire coating material, but uses an electron beam and argon plasma to evaporate the coating material from the surface of the coating material in an atomic or molecular state and adhere to the surface of the adherend, thereby depositing the surface of the adherend It is a method of coating with a thin film.

In order to increase the surface reflectivity of the adherend, aluminum (Al) and silver (Ag) are typically used as the coating material used when thermally depositing or sputtering the surface of the adherend with a coating material. Silver (Ag) is aluminum (Al). Compared to aluminum, the price is very expensive, and the evaporation rate is slow compared to aluminum, so the production rate is very slow. On the other hand, aluminum has the advantage of being very cheap compared to silver and having a very fast production rate because of its fast evaporation rate. However, when aluminum is coated with the same thickness, there is a disadvantage that the reflectivity is lower than that of silver. Therefore, when the deposition or sputtering using aluminum has a high production speed, there is an advantage of high productivity and low production cost. However, aluminum has a limited reflectance due to its metallic properties. If the deposition or sputtering is performed only with aluminum, the reflectance is about 94% and it is difficult to obtain a reflectance higher than that. That is, in the case of aluminum, even though the deposition or sputtering rate is lowered to increase the coating thickness, the reflectance does not rise more than 94%. Therefore, the method of performing vapor deposition or sputtering using only aluminum cannot be applied to a reflective sheet having a reflectance of 97% or more.

On the other hand, in the case of depositing or sputtering with silver (Ag), a reflectance of about 97% can be obtained, but there is no economic feasibility because the production speed is very slow and the production cost is very expensive. Therefore, the problem to be solved in the present invention relates to a method of manufacturing a reflective sheet having a reflectance of 97% or more while significantly lowering the production cost.

When aluminum is used as the coating material, and the coating is applied to the adherend by vapor deposition or sputtering, a reflectance of up to 94% can be obtained. Aluminum has a very fast evaporation rate, so even if it is deposited at a very fast rate by a thermal evaporation method, the reflectance can be obtained up to 94%. As shown in Fig. 1, the film 3, which is the adherend, is mounted over the unwinder 1, the cooling roll 4, and the rewinder 2 inside the vacuum chamber 8 and mounted. When the cooling roll 4 is cooled, and the aluminum 6 is heated in the heating furnace 5, the aluminum vapor 7 adheres to the film surface to be adhered. Such aluminum can be produced at a high speed of 300 m / min to 500 m / min using a vacuum thermal vapor deposition equipment to obtain a reflectivity of 94%. As described above, when vacuum thermal evaporation is performed at high speed using aluminum, since the productivity is high and the aluminum is also inexpensive, a deposition coating film having a reflectivity of 94% can be obtained at a very low production cost.

However, if silver (Ag) is used to coat the adherend by thermal evaporation or sputtering, a reflectance of up to 97% can be obtained, but silver (Ag) has a slow evaporation rate, so the production speed (moving speed of the film) is reduced. It should be deposited or sputtered at about 0.5 m / min to 1 m / min. Therefore, the productivity is only about 1/100 of that of aluminum, so the production cost is increased by about 100 times, so there is no economic feasibility. Accordingly, the present invention provides a method for manufacturing a reflective sheet having a reflectance of 97% or more and a very high productivity.

That is, in the present invention, aluminum is used in one step to produce vacuum reflective film having a reflectivity of 94% by performing vacuum thermal vapor deposition at a high speed of 300 m / min to 500 m / min. Take out the deposited film roll from the vacuum chamber and mount the roll on the silver (Ag) sputtering equipment in two steps to perform silver (Ag) sputtering at a speed of 5 m / min to 15 m / min on the aluminum vacuum heat-deposited film surface. do. In the sputtering window (FIG. 2), the adherend film 11 is mounted through the unwinder 9, the rewinder 10, and the cooling roll 12. Vacuum is applied to the vacuum chamber 17, and argon gas is injected through the argon (Ar) gas inlets 13 and 14 while moving the adherend film. As the adherend passes through the silver (Ag) targets 15 and 16, silver (Ag) is coated on the surface of the adherend. When sputtering is performed in this manner, the reflectance is additionally increased by about 3% to obtain a reflective film having a reflectivity of about 97% or more.

As described above, in order to obtain a reflectivity of 97% or more by thermal evaporation or sputtering using only silver (Ag), the production speed (moving speed of the film) should be about 0.5 m / min to 3 m / min. As a method, after performing aluminum thermal evaporation at a high speed of 300 m / min to 500 m / min in one step to produce a reflective sheet having a reflectivity of about 94%, the speed is 5 m / min to 15 m in two steps. When sputtering silver (Ag) at a rate of / min, it is possible to produce a reflective sheet having a reflectance of 97% at a speed of about 5 times or more than a production hole for obtaining a reflectance of 97% using only silver (Ag). Therefore, a highly reflective reflecting sheet can be produced at a very low production cost.

In the case of deposition or sputtering with silver (Ag), a reflectance of about 97% can be obtained, but there is no economical efficiency because the production speed is very slow and the production cost is very expensive. Therefore, as in the method of the present invention, when aluminum is used as a coating material to produce a reflective sheet with a reflectivity of 94% at a high-speed production speed in one step and then silver (Ag) as a coating material in two steps, the reflectance is More than 97% of reflective sheets can be produced at very low production costs. That is, using the same method as the present invention, it is possible to produce a reflective sheet having a reflectivity of 97% or more at a production cost of about 1/5 of the production cost of the existing silver reflective sheet.

Figure 1 is a schematic diagram of a vacuum deposition apparatus that deposits on the film surface by thermal evaporation using aluminum as a coating material, and Figure 2 is a sputtering method using silver (Ag) as a coating material. It is a schematic diagram of a sputtering device that deposits on the film surface, and Fig. 3 shows the steps in which aluminum and silver are coated on the surface of an adherend (PET film) by thermal evaporation and sputtering, respectively.

The vacuum level inside the vacuum chamber (8) is 1.0 × 10 ^-4 mbar using aluminum (6) with a purity of 99.9% using vacuum thermal evaporation equipment on an optical PET film (H34P from Kolon Corporation) that has been primed in one step. The deposition speed was deposited at a rate of 300 m / min to 500 m / min by setting the temperature of the cooling roll (4) wrapped around the film to -10 ° C to -20 ° C with 9.0 × 10 ^-4 mbar. A deposition film was prepared under the same conditions as in the following Examples, and surface reflectance was measured using a reflectometer (Minolta CM-3500d). Table 1 shows the reflectance measurement results of the aluminum vacuum heat-deposited film under the above conditions.

Example Example Vacuum degree
(× 10 ^-4 mbar) Cooling roll temperature
(℃) Deposition speed
(m / min) reflectivity
(%, L ^* ) Example 1 7.5 -10 300 89.1 Example 2 7.5 -10 400 88.2 Example 3 7.5 -10 500 83.7 Example 4 5.0 -15 300 94.4 Example 5 5.0 -15 400 91.8 Example 6 5.0 -15 500 90.1 Example 7 2.5 -20 300 94.6 Example 8 2.5 -20 400 93.0 Example 9 2.5 -20 500 92.2

Among the above examples, aluminum was deposited by mounting the sample of Example 4 (vacuum degree 5.0 × 10 ^-4 mbar, cooling roll temperature -15 ° C, deposition speed 300 m / min) on a silver (Ag) sputtering equipment (FIG. 2). Sputtering was once again performed using silver (Ag) on the deposited surface. The sputtering conditions are as follows.

Targeting silver (Ag) and using two DC sputters (5KW) (15,16), the pressure inside the vacuum chamber (17) is fixed at 5.0 × 10 ^-4 mbar, and the Ar gas inlets (13,14) The injection speed through was 300 sccm (standard cubic centimeter per minute) to 500 sccm, and sputtering was performed while changing the speed. Table 2 is an example when sputtering is performed under these conditions.

Example Adherend Example Vacuum degree
(× 10 ^-4 mbar) Ar injection speed
(sccm) Sputtering speed
(m / min) reflectivity
(%, L ^* )
H34P
Example 10 5.0 500 0.5 98.1 Example 11 5.0 500 2 71.4 Example 12 5.0 500 10 63.5

Example 4


Example 13 5.0 300 5 98.5 Example 14 5.0 300 10 97.1 Example 15 5.0 300 15 96.0 Example 16 5.0 500 5 98.6 Example 17 5.0 500 10 97.7 Example 18 5.0 500 15 96.8

Examples 10 to 12 are examples in which sputtering was performed using a primer-treated optical PET film (H34P from Kolon), and Examples 13 to 18 were aluminum vacuums in Example 4 as adherends. It is using a deposited film. That is, Examples 10 to 12 were performed with silver (Ag) sputtering on a transparent PET film on which nothing was deposited, and Examples 13 to 18 were again subjected to silver (Ag) sputtering on the surface of the aluminum heat-deposited film. will be.

Sputtering speed must be very slow, about 0.5 m / min, to obtain silver (Ag) sputtering on a transparent PET film on which nothing is deposited to obtain a reflectivity of 97% or higher. However, when the silver (Ag) sputtering is performed again on the aluminum vacuum-deposited surface, a surface having a reflectivity of 97% can be obtained even when the sputtering speed is 5 m / min to 15 m / min at a very high speed. That is, Example 13 (vacuum degree 5.0 × 10-4 mbar, Ar injection speed 300 sccm, sputtering speed 5 m / min), Example 14 (vacuum degree 5.0 × 10-4 mbar, Ar injection speed 300 sccm, sputtering speed 10 m / min), Example 16 (vacuum degree 5.0 × 10-4 mbar, Ar injection speed 500 sccm, sputtering speed 5 m / min), Example 14 (vacuum degree 5.0 × 10-4 mbar, Ar injection speed 500 sccm, sputtering In the case of speed 10 m / min), a reflectance of 97% or more can be obtained.

1,9: Unwinder
2,10: Rewinder
3,11,18: PET film
4,12: Cooling roll
5: Boat
6: Aluminum
7: aluminum steam
8,17: Vacuum chamber
13,14: Argon (Ar) gas inlet
15,16: Silver (Ag) target
19: aluminum (Ag) deposition layer
20: silver (Ag) deposited layer

Claims (5)

Coating the surface of the PET film or plastic substrate using aluminum (Al) as a coating material by a thermal evaporation method, and additionally coating silver (Ag) on the surface of the aluminum thermal deposition coating. Reflective film production method comprising the step of performing a coating by sputtering (sputtering) method using as In claim 1, the coating material used for thermal evaporation (thermal evaporation) is a reflective film production method using a purity of 90% or more In claim 1, the coating material used for sputtering (sputtering) is silver (Ag) is a reflective film production method using a purity of 90% or more Method of manufacturing a reflective film having a reflectance of 97% or more of the reflective film produced by the method of claim 1 In claim 1, when sputtering with silver (Ag), the PET film or plastic substrate has a moving speed of 5 m / min or more.

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