JPS59174546A - Mirror - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a mirror, characterized in that a reflective layer is applied to the back side of a transparent glass sheet, and one or several protective layers are coated on top of said layer. be.

In the most common mirror manufacturing process, the back side of a transparent glass sheet is coated with a reflective layer, usually silver.

This silver layer is covered with a copper layer, which is then applied with paint or face. The paint layer protects the underlying metal layer from corrosion and wear.

The main disadvantage of such a method is that the protective paint layer takes some time to dry, so it is necessary to store newly manufactured mirrors so that the back side does not come into contact with other objects while the paint is still wet. It's in the wrong place. This is inconvenient for large-scale production of mirrors, as it requires a very large storage space.

In conventional manufacturing methods, the protective layer is solidified by evaporation of the solvent. Therefore, in large-scale production, solvent evaporation poses a problem of polluting the factory atmosphere. Also, sufficiently rapid drying is not achieved without heating these mirrors.

One object of the invention is to provide a method for manufacturing mirrors that does not have these drawbacks.

According to the invention, a reflective layer is applied to the back side of a transparent glass sheet, and one or several protective layers are coated on top of this reflective layer, said protective layer being applied to the backside of the sheet by electron beams. A method of manufacturing a mirror is provided, characterized in that a coating of a curable resin composition is applied and the resin is cured in one or several electron beams to form an adhesive protective layer.

By utilizing the present invention, the resin layer is cured in seconds, and thus newly manufactured mirrors can be stacked as desired without the need to take care to prevent wet protective layers from clumping together, allowing for continuous production. It can be easily implemented. The problem of solvent evaporation is also substantially avoided.

Furthermore, electron beam curing has significant advantages over curing methods using optical radiation. First, there is no need to add a photoinitiator into the resin composition. 11!2 Since there is no need for the resin layer to be transparent to optical radiation, any desired pigments or fillers can be added to the resin, and the resin layer can be made thicker to provide good protection for the reflective layer. can give.

In fact, there has been a prejudice that it is undesirable to cure resin compositions applied to glass sheets with electron beams for any reason. This is because it has been theoretically inferred that irradiating a glass sheet with an electron beam will have an adverse effect on its optical properties. However, this time it was found that the expected adverse effect was not so great, and the deterioration in the mirror properties was within tolerable limits. Therefore, electron beam curing can be utilized with the various advantages mentioned above.

The electron beam curing must be carried out in an inert atmosphere, such as a nitrogen atmosphere. The presence of oxygen at this stage has a negative effect on the quality of the protective cover formed. A substantially inert atmosphere can be maintained very easily even in continuous operation, for example by carrying out the curing in a tunnel chamber with a continuous supply of inert gas at or above atmospheric pressure. It is preferred to use nitrogen as the inert gas because it is economical and convenient.

The resin composition used preferably consists of the following in weight fr%:

Plasticizer θ~40% Pigment and/or filler 0~40% Other additives 0.5~10% The electron beam acts on this base material to achieve rapid curing through chain extension and/or cross-linking reactions. Examples of suitable oligomers are of the following types: polyurethane acrylates, epoxy acrylates, polyester-polyol acrylates, polyether-polyol acrylates and polyene-polythiols.

Reactive diluents are used, for example, to reduce the viscosity of the base material. In particular, mono- or polyfunctional acrylates are used to reduce the viscosity of polyurethane and epoxy acrylate-based materials. The reactive diluent is mixed with the base material when the base material is activated with an electron beam.

Plasticizers, pigments, fillers and other additives commonly used in paint manufacture are also optionally used.

Advantageously, said curing is carried out by stroking the resin-coated side of the sheet with a curtain-like electron beam(s). This is a simple and convenient method for curing.

Preferably, the radiation curable resin coating described above is applied by curtain coating. Such a method is advantageous in producing thin coatings of high quality and uniform thickness.

The resin coating has a thickness of at least 20 μm, preferably 3 μm.
Advantageously, it is applied and cured to provide an adherent protective layer of 0 to 80 μm.

A coating of the above minimum thickness provides excellent protection for the reflective layer, and a thickness in the above preferred range ensures ease of curing and economical use of the resin.

For said curing, the resin composition is preferably allowed to absorb 3-Ion rad. Such an amount contributes to rapid curing by one effective force.

The present invention has particular application in continuous line production of mirrors in which a large number of mirrors are transported successively through resin coating and curing stations.

The present invention includes mirrors made by the methods described herein, and also extends to intermediate products used in such methods.

Therefore, the present invention also provides an electron beam curable resin composition, which is an intermediate product used for manufacturing mirrors according to the method of the present invention, in which a reflective layer is provided on the back side of a transparent glass sheet, and which is cured to obtain an adhesive protective layer. A surface coating of an object is provided.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

Figure 1 shows a reflective layer 2 on the back (top) of a transparent glass sheet 1.
1 and having thereon an intermediate layer 3 and a protective layer 4 made of an electron beam cured resin coating.

For example, the reflective layer 2 of silver and the intermediate layer 3 of copper are applied in known manner. The main purpose of the intermediate layer 3 is to prevent the reflective layer 2 from oxidizing. The present invention is characterized in that a protective layer 4 is applied.

An apparatus for applying the adhesive protective layer 4 is shown in FIG.

In FIG. 2, a transparent glass sheet 5 with a reflective coating (not shown) and an optional intermediate coating (not shown) is conveyed to a conveyor 6.
is passed under a coating device 7, preferably a curtain coating device, where a coating 8 of electron beam curable resin is applied. The conveyor 6 transports the thus coated sheets into a tunnel chamber 9 where the WI 8 is treated with an electron beam IO generated by a curtain-type electronic processor 11. The tunnel chamber 9 is flushed with an inert gas, for example nitrogen gas, from a tank 12.The tunnel entrance 13 is as low as possible leaving a space between it and the covering sheet 5, and the tunnel exit 14
In order to reduce the consumption of gas from the tank 12 and to facilitate maintaining a substantially inert atmosphere within the tunnel chamber 9, a flexible curtain 15. is provided as shown. It does not matter if it is sealed.

In one particular embodiment, the mirror-coated glass sheet 5 has a diameter of 2.0
From the curtain coating method, an electron beam curable resin coating is applied, conveyed at a speed of 7 minutes.

Each electron beam accelerator serves a sheet width of 1.7 m, and two accelerators are provided end-to-end to process a 3.4 m wide sheet.

These accelerators were 175 KaV accelerators available from E.N.I. of Zieneva, but l5Q KaV accelerators could also be used.

The resin coating was applied to a thickness of 60 μm, which corresponds to about 120 t/l, although it of course varies depending on the resin composition used. The amount absorbed by the resin coating is 6 mrad (6X
IC1-IIGy).

The resin composition used has the following general composition (% by weight):

Electron beam curable base material containing unsaturated monomers or oligomers 10-90%
Plasticizer 0-40% Pigments and/or fillers 0-40% Other additives
0.5 to 10 - The present invention will be explained below with reference to Examples.

Example 1 Plex 662B-0 (OM Co., Ltd.) 60 weight i
t% Lead oxide 7 Titanium oxide 7 Calcium carbonate i.

Example 2 Diethylene glycol diacrylate 15 dioctyl phthalate 2 as electron beam curable base material.

Lead oxide 7 Calcium carbonate 1° Barium sulfate
1゜Example 3 Tetraethylene glycol diacrylate 1
5 Lead oxide 5 Calcium carbonate 7 Magnesium carbonate 15 Iron oxide
4 The light reflectance and energy reflection properties of a mirror thus protected are substantially the same as those of a similar mirror without the protective i11 layer cured by electron beam irradiation.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a mirror manufactured by the method of the present invention, and FIG. 2 is a schematic cross-sectional view of a portion of the apparatus used in the method of the present invention. Patent applicant Gravel Bell ν No. 1 Procedural amendment parasitic sulfur 3, relationship with the case of the person making the amendment 1 "ν shi'4, agent

Claims (1)

[Claims] 1. A reflective layer is applied to the back surface of a transparent glass sheet, and the reflective layer is covered with one or more protective layers, and the protective layer or one layer is made of glass. 1. A method for manufacturing a mirror, comprising applying an electron beam curable resin composition to the coated back side of a sheet and curing the resin in an electron beam (or groups) to form an adhesive protective layer. 2. The method according to claim 1, wherein the resin composition comprises, by weight, 0 to 40% plasticizer, 0 to 40% pigment and/or filler, and 0.5 to 10% other additive(s). 3. The method according to claim 1 or 2, wherein the curing is carried out by sweeping the resin-coated surface of the sheet with a curtain-like electron beam (group). 4. The method according to any one of claims 1 to 3, wherein the radiation-curable resin coating is applied by a curtain coating method. 5. The resin coating is applied and cured in such a way as to leave an adhesive protective layer with a thickness of at least 20 μm, preferably between 30 and 80′ μm.
The method according to any of paragraph 4. 6. The method according to any one of claims 1 to 5, wherein the resin composition is made to absorb an electron beam of 3 to 10 rad for curing. 7. A method according to any one of claims 1 to 6, in which a number of mirror groups are conveyed successively through a resin coating station and a curing station. 8. A method of manufacturing a mirror according to substantially any of the claims herein. 9. A mirror manufactured by the method according to any of the claims. 10. The transparent glass sheet according to any one of claims 1 to 8, which has a reflective layer on the back surface and a surface coating of a curable electron beam curable resin composition to form an adhesion protective layer. Intermediate products used in the manufacture of mirrors by process.