JPS6134386B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly durable and selectively transparent laminate.

The selectively transparent laminate is, for example, transparent to visible light but reflective to far infrared rays. Using this laminate can prevent heat transfer due to radiation, so it functions as a transparent heat insulating window. For example, if this laminate is applied to a single-pane window, it will provide the same insulation effect as a double-pane window.

Laminated bodies with such performance can be used in solar energy collectors, water heaters; greenhouses, windows in buildings;
It can be used in freezers, refrigerated cases, windows of vehicles or aircraft, etc., and its function as a transparent heat-insulating window that utilizes solar energy and prevents energy radiation will become increasingly important in the future.

In order to achieve this objective, it is desired that durable selective light transmitting laminates be industrially available at low cost and in large quantities.

Laminated bodies used in solar systems and the like in the prior art are those in which a thin metal film of gold, silver, copper, aluminum, etc. is provided on a transparent substrate made of an organic material. Furthermore, in order to improve the transparency in a specific wavelength range, a technique is also known in which a transparent thin film layer with a high refractive index is coated on a metal thin film, and a structure in which a metal thin film is sandwiched between thin films with a high refractive index is also known. is also well known.

However, when a laminate with selective light transmittance is applied to windows of buildings or show cases,
It was found that after a certain period of time, spot-like stains appeared. The occurrence of stains is particularly noticeable on laminated glass windows with dew condensation or those that are wetted by cleaning with tap water. In order to prevent this staining, a transparent protective film made of a polymeric material such as polyacrylic resin or polyacrylonitrile resin is applied to a thickness of 2 to 10 μm.
Even if a metal thin film (or a thin film of a substance having a high refractive index) is coated with an adjustment to m, the occurrence of these blotchy spots cannot be suppressed. Of course, if the transparent protective film is made sufficiently thick, spots can be prevented, but the absorption of far infrared rays increases, which impairs the heat insulation performance of the laminate.

The inventor of the present invention has arrived at the present invention through intensive research into a durable laminate that can maintain its heat insulating effect and does not cause stains.

That is, the present invention comprises a transparent molded substrate (A), a selectively permeable membrane (X), an intermediate layer (D), and an organic transparent protective layer (E).
and are laminated in this order,
The selectively permeable membrane is composed of a metal thin film layer (B) and, if necessary, a thin layer (C) of a high refractive index material, and the intermediate layer is made of R ¹ Si.
This is a laminate characterized by being an organic silane compound represented by (OR ² ) ₃ . Here, R ₁ is an organic group having 10 or less carbon atoms and containing at least one of vinyl group, epoxy group, amino group, and mercapto group, and R ² is any one of methyl group, ethyl group, and methoxyethyl group. That's it.

The present invention will be explained.

The material for the base of the transparent molded product used in the present invention may be either organic or inorganic. Examples of the organic material include a thermoplastic polymer sheet or film, and examples of the inorganic material include a glass plate.

Examples of the metal thin film layer include gold, silver, copper, aluminum, or an alloy or multilayer body made of at least two or more of these metals. Preferred metal thin film layers are a silver-copper alloy film and a gold-silver alloy film.

The thickness of the metal thin film layer is not particularly limited as long as it has transparent conductivity or selective light transmittance. Usually, the film thickness is preferably about 40 Å to 500 Å, and particularly preferably 100 Å to 200 Å in order to have both sufficient transparency and sufficient conductivity. If the thickness is less than 40 Å, it will not form a completely continuous thin layer and will tend to form an island structure.
If it exceeds Å, transparency will be impaired. Examples of means for forming such a metal thin film include vacuum evaporation, cathode sputtering, ion plating, and plasma spraying, with vacuum evaporation and cathode sputtering being preferred.

The organic transparent protective layer is provided to improve scratch resistance and light resistance. Examples include polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyacrylonitrile, polymethacrylonitrile, poly(meth)acrylate ethylene-vinyl acetate copolymer, polystyrene, polyvinyl chloride, vinyl acetate-vinyl chloride copolymer, Examples include vinyl chloride such as vinyl chloride and vinylidene monochloride, nylon, polyfunctional poly(meth)acrylate, diethylene glycol bisallyl carbonate, and melamine.

The optimum film thickness varies depending on the far-infrared transmittance of the transparent protective layer. Olefin-based transparent protective layers such as polyethylene and polypropylene have a heat insulation effect even when the thickness is 40 to 50 μm, but when the thickness of polyethylene terephthalate, polyacrylate, etc. is 20 μm, the heat insulation effect is significantly This makes it unsuitable for use in insulated windows. However, it still has the function of adjusting sunlight.

The intermediate layer of the present invention is an organosilicon compound represented by the general formula R ¹ Si(OR ² ) ₃ . Here, R ¹ is the number of carbon atoms having at least one of vinyl group, epoxy group, amino group, and mercapto group.
It is an organic compound with a size of 10 or less, and R ² is a methyl group, an ethyl group, or a methoxyethyl group.

Specific examples include vinyltriethoxysilane,
vinyltris(β-methoxyethoxy)silane,
β-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, N-β(aminoethyl)γ-
Examples include aminopropyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane.

The effects of the organosilicon compound in the present invention are not limited to the specific examples described above.

In the present invention, a transparent dielectric thin layer having a high refractive index can be laminated on the metal thin film layer in order to increase transmittance in the visible region or to improve adhesiveness. Here, the high refractive index dielectric is 589nm.
The refractive index measured in is 1.4 or more, preferably 1.6 or more, more preferably 1.7 or more. Titanium monoxide, titanium dioxide, zirconium oxide, bismuth oxide, tin oxide, indium oxide,
Examples include silicon oxide, zinc oxide and barium oxide.

Among these, titanium oxide such as titanium monoxide and titanium dioxide, silicon oxide, and zinc oxide are preferable from the viewpoint of transparency and film formation speed, and titanium oxide is particularly preferable because of its excellent optical properties such as visible light refractive index and transparency. preferable.

The transparent high refractive index thin film layer can be formed by either a physical method such as vapor deposition or a chemical method such as thermal hydrolysis.

Each of these layers is laminated in the following configuration order.
Assuming that the transparent molded substrate A, the metal thin film layer B, the transparent high refractive index dielectric thin layer is C, the organosilicon compound intermediate layer is D, and the organic transparent protective layer is E, (1) A\C\B Examples of configurations include \C\D\E (2) A\C\B\D\E (3) A\B\C\D\E (4) A\B\D\E.

The intermediate layer D of an organosilicon compound is dissolved in a suitable solvent, and then coated with a transparent protective layer E using a bar coater or the like.
Alternatively, it can be applied to the surface of the metal thin film or thin layer C, or other methods such as dipping, spraying, spinner coating, machine coating, etc. can be used as is, and the solution can be dried in a dryer or the like. It can be heat treated.

At this time, water and a curing accelerator may be added to the solution in order to increase the curing speed of the organosilicon compound.

In the present invention, by sequentially forming each layer, a laminate that is _highly effective in preventing the occurrence of spot-like stains can be obtained. The laminate is
It shows particularly remarkable durability.

As a thermal initiator, an azone compound such as azobisisobutyronitrile, benzoyl peroxide,
Examples include peroxides such as lauryl peroxide, di-tert-butyl peroxide, and dicumenyl peroxide. These peroxides can also be used in combination. The amount used is in the range of 0.01 to 10% by weight based on the organic transparent protective layer resin component.

In order to demonstrate the superior durability of the selective light transmitting laminate of the present invention, the following experiment was performed.

The sample was attached to the glass surface on the indoor side of a window facing south, a nozzle was installed at a distance from the laminate, and tap water was sprayed at a cycle of 1 minute every 2 hours. The sprayed tap water wetted the laminate almost uniformly, and the deposited tap water had dried before the next water spray was applied.

Hereinafter, the effects of the laminate of the present invention will be described based on Examples.

Example 1 A solution consisting of 3 parts of tetrabutyl titanate tetramer, 65 parts of isopropyl alcohol, and 32 parts of n-hexane was applied onto a transparent biaxially stretched polyester film using a bar coater, and the coated material was
A titanium oxide layer with a thickness of 250 Å was formed by heating at ℃ for 3 minutes, and a thin film of an alloy of silver and copper (silver/copper = 90/10) with a thickness of 180 Å was further formed on this titanium oxide layer.

Silver-copper alloy layer is silver-copper alloy (70% silver, 30% copper)
Vacuum deposition was performed using a resistance heating method. Next, a 250 Å titanium oxide layer was formed on the silver-copper alloy layer in the same manner as the second layer, and on top of that was a β-(3.4
- An organosilicon compound solution prepared in a ratio of 1 part - epoxycyclohexyl)enaltrimethoxysilane, 1 part water, and 8 parts isopropyl alcohol was coated with a bar coater, heat-treated at 130°C for 5 minutes, and a thickness of 0.1 μm was applied. A membrane was provided.

Furthermore, a cyclohexanone solution of polymethacrylonitrile was applied on top of this using a bar coater.
Drying at 130° C. for 5 minutes provided a 2 μm thick film.

The obtained laminate was pasted on the window of the above-mentioned mounting durability testing device and evaluated.

The laminate of this example did not develop any speckled stains even after 30 days. Also, infrared wavelength 4μm ~ 25μm
The average value of infrared reflectance at m was 84%.

Comparative Example 1 A laminate was formed in exactly the same manner as in Example 1 except for the organosilicon compound layer with respect to the other layers. Paste this on the window of the mounting durability test equipment,
When tested, many spots appeared after 3 days.

Example 2 A 250 Å thick titanium oxide layer was provided on a transparent biaxially stretched polyester film in the same manner as in Example 1, and on top of that a 180 Å thick silver and gold alloy (silver/gold = 80/20) was used as a metal. was installed using the sputtering method. A 250 Å thin film layer of titanium oxide was applied on top of this using the same method, and then a solution prepared in a ratio of 1 part vinyltris(β-methoxyethoxy)silane, 1 part water, and 8 parts isobutabyl alcohol was applied using a bar coater. Then, heat treatment was performed at 130°C for 5 minutes to form a film with a thickness of 0.1 μm. On this membrane,
Furthermore, a solution prepared in a ratio of 1 part of polymethacrylonitrile to 9 parts of cyclohexane and 0.02 parts of benzoyl peroxide was applied with a percoater, heat-treated at 130°C for 5 minutes, and a 2μ
A film of m was obtained. The obtained laminate was evaluated by pasting it on the window of the mounting durability test device mentioned above, but
No spot-like stains appeared even after a day had passed. Also, the average infrared reflectance at an infrared wavelength of 4 to 25 μm is
It was 84%.

Comparative Example 2 A laminate was formed in exactly the same manner as in Example 2 except for the organosilicon compound layer with respect to the other layers.

Regarding this, paste it on the window of the mounting durability test equipment,
When tested, numerous spots appeared after 7 days.

Example 3 Similar to Example 1, on a polyester film
A 250 Å titanium oxide layer is placed on top of a 180 Å thick titanium oxide layer.
A silver-copper alloy metal (90 silver/10 copper) was prepared.

Next, a solution prepared in a ratio of 1 part N-β (aminoethyl) γ-aminopropyltrimethoxysilane to 1 part water and 8 parts isopropyl alcohol was applied onto this using a bar coater, and heat treatment was performed at 130°C for 10 minutes. , a film with a thickness of 0.1 μm was provided.

Furthermore, a dimethylformamide solution of polyacrylonitrile was applied on top of this using a bar coater, and 130
Drying was performed at ℃ for 5 minutes to provide a 2 μm thick membrane. When the obtained laminate was tested by pasting it on the window of a mounting durability testing device, no abnormality was observed even after 30 days had passed.

Example 4 A 240 Å titanium oxide film was provided on a transparent biaxially stretched polyester film by an electron beam method.
A 180 Å silver-copper alloy thin film layer (silver/copper = 90/10) was formed thereon by the resistance heating method as in Example 1, and then a 240 Å titanium oxide film was formed thereon by the electron beam method.

Furthermore, a solution prepared in a ratio of 1 part of γ-mercaptopropyltrimethoxysilane to 1 part of water and 8 parts of isopropyl alcohol was coated with a bar coater, and heat treated at 130°C for 5 minutes to a thickness of 0.1 μm.
A membrane was provided.

Furthermore, a cyclohexanone solution of polymethacrylonitrile was applied on top of this using a bar coater.
Heat treatment was performed at 130° C. for 5 minutes to form a 2 μm film. When the obtained laminate was pasted on the window of a mounting durability testing device and tested, no abnormality was observed even after 30 days had passed.

Example 5 A 170 Å thick layer of silver was deposited on a polyester film.
A gold-copper alloy layer (silver/gold/copper = 75/20/5) was formed by sputtering, and then a 240 Å titanium oxide layer was formed by coating a tetrabutyl titanate solution in the same manner as in Example 1. was formed.

Next, a solution prepared in a ratio of 1 part β-(3,4 epoxycyclohexyl)ethyltrimethoxysilane to 1 part water and 8 parts isopropyl alcohol was applied onto it using a bar coater, and heat treatment was performed at 130°C for 5 minutes. A film with a thickness of 0.1 μm was obtained. Furthermore,
A 2 μm film of polymethacrylonitrile was provided thereon by the method described above.

When the laminate of this example was tested using a mounting durability tester, no abnormality was observed even after 30 days.

Comparative Example 3 A laminate of polyester film\silver-gold-copper alloy\titanium oxide\polymethacrylonitrile was formed using the same method as in Example 5 except for the hardened layer of the organosilicon compound. When tested using a durability testing device, numerous spot-like stains appeared within 4 days.

Example 6 On both sides of a transparent biaxially stretched polyester film, a 250 Å titanium oxide layer, a 180 Å silver-copper alloy layer (silver/copper = 90/10),
250 Å titanium oxide layer, 0.1 μ β-(3,4 epoxycyclohexyl)ethyltrimethoxysilane layer
A layer of 2 μm of polymethacrylic nitrile was sequentially provided and evaluated by attaching it to the window of a mounting durability testing device.

This laminate did not develop any speckled stains even after 25 days.

Claims (1)

[Scope of Claims] 1. A selectively permeable membrane including a metal thin film layer is provided on at least one side of a transparent molded substrate, and an intermediate layer and an organic material are provided on the selectively permeable membrane on the opposite side to the molded substrate. In the laminate provided with a transparent protective layer, the intermediate layer has the following formula R ¹ Si(OR ² ) ₃ [where R ¹ is at least one group selected from a vinyl group, an epoxy group, an amino group, and a mercapto group. is an organic group having 10 or less carbon atoms, and R ² is a methyl group, an ethyl group, or a methoxyethyl group. ] A laminate characterized by comprising an organic silane compound represented by: 2. A laminate according to claim 1, comprising an intermediate layer made of an organic silane compound containing a vinyl group and a transparent protective layer formed from a thermal initiator.