JP5791453B2 - Method for manufacturing composite structure - Google Patents

Description

  The present invention relates to a sheet-like composite structure having heat insulating properties and hydrophobic properties.

The energy problem has become a global issue, and energy consumption reduction and alternative energy technology development are actively carried out. There are also many related products on the market.
For example, as global warming has progressed, the rise in indoor temperatures of buildings, houses, cars, etc. due to thermal energy from sunlight is serious. Important from the point of view. For this reason, thermal barrier films, low-e double glazing, and the like are rapidly spreading.

Moreover, the transparent heat insulation film used by sticking to the window glass which suppresses that indoor temperature (heat) hold | maintained by winter heating is scattered outside through a window glass is also marketed.
On the other hand, especially in winter, the outdoor temperature is low compared to the room temperature, and the window glass condenses, which impedes visibility, and the window glass is contaminated and moldy due to condensed water droplets for safety and environmental protection of the living space. It is a problem. Especially in the case of automobiles, fogging of glass in winter is a big safety issue and consumes electric power to solve it. As the shift from conventional automobiles that use fossil fuel combustion as a power source to hybrid and electric cars using batteries together, the load on the batteries increases. Anti-fogging measures have become an urgent issue to reduce battery load.

  As a method for suppressing dew condensation on window glass or the like, there is a method for preventing fogging by interposing a heat insulating film or the like on the glass surface to prevent a temperature drop of the inner surface due to the low temperature outer surface, and many products are sold. Moreover, the anti-fogging heat insulation sheet which improved the anti-fogging function by forming the hydrophilic film bridge | crosslinked by electron beam irradiation on the surface of a heat insulation film is proposed (refer patent document 1).

Japanese Patent No. 2711857

  As shown in Patent Document 1, there has been a sheet that exhibits the antifogging function by making the surface hydrophilic, but an antifogging heat insulating sheet capable of obtaining high hydrophobicity that repels fine water droplets has been proposed. Absent.

  The objective of this invention is providing the composite structure which has heat insulation and hydrophobicity, and the manufacturing method of the said composite structure.

The composite structure made in order to solve the above-mentioned problem has, as a main component, at least one selected from the group consisting of a first film mainly composed of a fluororesin and polyethylene, polyester, and polycarbonate. A second film, and an intermediate layer mainly composed of titanium oxide and formed between the first film and the second film, the intermediate layer and the second film, Is a composite structure joined by a silane coupling agent or a titanate coupling agent.

  Conventionally, it has been difficult to join the first film and the second film, but the inventor of the present invention forms a titanium oxide layer on the first film, and the layer and the second film. It was discovered that the first film and the second film can be joined by joining the film with a silane coupling agent.

  In the composite structure having the above structure, the first film has high hydrophobicity (water repellency), and the second film has high heat insulation. Therefore, this composite structure has both heat insulating properties and hydrophobic properties, and can be used in various situations.

By forming the composite structure of the present invention into a sheet shape, it can be used by being attached to a glass surface, a wall, or the surface of various objects.
As the first film and the second film in the composite structure of the present invention, those having a visible light transmittance of 75% or more may be used. By configuring the composite structure as described above, it can be used on a surface requiring visibility such as a glass surface. In particular, when used as vehicle glass, excellent effects can be exhibited.

  The intermediate layer described above may be a titanium oxide film having a thickness of 2 nm to 1000 nm. Thus, the visibility as the whole composite structure can be improved by forming a thin titanium oxide film.

The invention according to claim 1 , which has been made to solve the above-described problem, includes a step of forming an intermediate layer mainly composed of titanium oxide on a first film mainly composed of a fluorine-based resin, A step of forming a first silane coupling agent film on the first film on which the intermediate layer is formed, and a second main component comprising at least one selected from the group consisting of polyethylene, polyester, and polycarbonate. A step of forming a second silane coupling agent film on the film; an intermediate layer on which the first silane coupling agent film is formed; and a second film on which the second silane coupling agent film is formed. And a step of bonding the composite structure.

  In such a production method, the first film and the second film can be bonded via the intermediate layer, and a composite structure having heat insulating properties and hydrophobic properties can be produced.

Schematic sectional view of the composite structure of the present invention

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the composite structure 1 includes a water-repellent film 11 mainly composed of a fluororesin, and a heat insulating film mainly composed of one or more selected from the group consisting of polyethylene, polyester, and polycarbonate. 13 and an intermediate layer 15 which is mainly composed of titanium oxide and is formed between the water repellent film 11 and the heat insulating film 13. In addition, the water repellent film 11 is an example of the 1st film of this invention, and the heat insulation film 13 is an example of the 2nd film of this invention.

  The composite structure 1 has a heat insulating function and an antifogging function. The anti-fogging function is realized by the water repellent film 11. Specifically, by making the surface hydrophobic (water-repellent), the condensed water droplets become minute water droplets on the water-repellent surface, and a plurality of water droplets aggregate to form water droplets and slide down due to gravity. Demonstrate.

The water-repellent film 11 includes a PCTFE (ethylene trifluoride chloride) film, an FEP (tetrafluoroethylene-hexafluoropropylene copolymer) film, a PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer) film, and PTFE. A (poly) ethylene-based transparent film containing fluorine such as (polytetrafluoroethylene) can be used. In these films, a remarkable water repellency can be obtained by using a film having a surface energy of 18 to 50 dyn / cm (= mN / m), particularly 18 to 30 dyn / cm.
Conventionally, a sheet with improved water repellency by providing fine irregularities on the surface has been proposed, but such surface-modified films are damaged by touching or rubbing with a hand, and the surface microstructure is broken. In addition, the attached fats and oils (for example, hand oil is mostly oleic acid) are embedded in the fine structure and become dirty. In particular, there was no water-repellent surface that could pass the strict durability test that can be used in the window glass of the driver's seat and passenger seat.
However, it is known that the above-described ethylene-based transparent film containing fluorine is relatively expensive, is a bulk film, and has a low coefficient of friction. That is, although these films may be inferior to the surface microstructure film in terms of water repellency, even if they are scratched and worn, they are bulk films and can maintain a certain water repellency.

Moreover, by using a film having a visible light transmittance of 75% or more as the water repellent film 11, it can be used in places where high visibility is required.
Further, when a tetrafluoroethylene film is used, it usually becomes cloudy and opaque, so that it can be formed very thin or a structure whose structure is adjusted to have transparency.

A film thickness of 50 μm to 300 μm can be used. These water-repellent films have the effect of preventing the adhesion of water droplets.
As the heat insulation film 13, a polyethylene, polyester, or polycarbonate resin film may be used. A film thickness of 50 μm to 100 μm can be used. Further, hollow nanoballoons may be mixed and dispersed by about 10 to 50%.

  The intermediate layer 15 is a titanium oxide (TiOx, x = 1.5 to 2.0) layer. Specific methods for forming the intermediate layer 15 include a method of forming a TiOx layer by hydrolysis of organometallic titanium, and a method of forming a TiOx layer on the water repellent film 11 by a vacuum film forming method. The thickness of the intermediate layer 15 is preferably as thin as possible, but is usually 2 nm to 1000 nm.

  The surface energy of the fluororesin of the water-repellent film 11 is approximately 20 dyn / cm and exhibits a water-repellent surface, so that it is difficult to bond to many objects, but titanium oxide is bonded relatively well. be able to. The surface of the water repellent film 11 on which titanium oxide is formed may be subjected to surface treatment such as plasma treatment in advance.

  The intermediate layer 15 is first formed on the water repellent film 11. A silane coupling agent or a titanate coupling agent is used for joining the intermediate layer 15 and the heat insulating film 13. At that time, for example, an epoxy silane coupling agent can be used on the heat insulating film 13 side, and an amino silane coupling agent can be used on the bonding layer 15 side.

Examples of the present invention will be described below. In addition, this invention is not limited to an Example at all, and as long as it belongs to the technical scope of this invention, it cannot be overemphasized that various forms can be taken.
[Example 1]
In this example, a heat insulating anti-fogging film comprising the composite structure of the present invention was prepared.

As a water-repellent film, a commercially available Niraco FEP (ethylene tetrafluoride-hexafluoropropylene copolymer resin film, 50 μm thick) was used as a fluorine-based film.
As the heat insulating film, Toyo Packaging CA80 (PET film, 80 μm thickness) was used. Both the FEP and CA80 have a visible light transmittance of 80%.

  In this example, the intermediate layer made of a very thin Ti oxide film is inserted into the bonding interface between the water repellent film and the heat insulating film, thereby realizing the bonding between the water repellent film and the heat insulating film. The joining procedure will be described below.

First, the surface of the water-repellent film was subjected to reduced-pressure glow-plasma treatment (RF 300 W, 10 minutes), and a titanium oxide film (TiO ₂ film) was formed to a thickness of 100 nm or less by a sputtering method without being exposed to the atmosphere.

  Next, the surface of the intermediate layer formed on the water repellent film is treated with atmospheric corona plasma, and then exposed to the gas vapor of silane coupling agent KBM903 (amino) manufactured by Shin-Etsu Chemical Co., Ltd. to expose the surface of the intermediate layer to the silane coupling agent. Was adsorbed.

  Next, the heat insulating film was subjected to an air corona treatment in the air, and then exposed to a gas vapor of a silane coupling agent KBM403 (epoxy system) manufactured by Shin-Etsu Chemical Co., Ltd. to adsorb the silane coupling agent on the surface of the heat insulating film.

  Next, the surfaces of the intermediate layer and the heat insulating film on which the silane coupling agent was adsorbed (the silane coupling agent film was formed) were bonded together by a laminator, and the joining was completed by heat treatment at 130 ° C. for 10 minutes. Thus, the heat insulation anti-fog film was manufactured. As a bonding method using a silane coupling agent, the technique described in WO / 2011/010738 can be used.

The heat-insulating anti-fogging film produced in this way was confirmed to have an anti-fogging property due to the high water-repellent property of the FEP film, together with an effect of about 30% of heat insulation in terms of energy saving of the air conditioner.
The composite structure (heat-insulating anti-fogging film) of the present invention can be expected to have a certain anti-fogging effect because the temperature decrease of the dew condensation surface is reduced by about 30% by the heat-insulating film. However, in cold districts and the like, it is predicted that the dew point will dew due to a severe temperature difference, but dew condensation can be further mitigated by the presence of a water repellent film such as an ethylene water repellent film.

DESCRIPTION OF SYMBOLS 1 ... Composite structure, 11 ... Water-repellent film, 13 ... Heat insulation film, 15 ... Intermediate layer

Claims (3)

Forming an intermediate layer mainly composed of titanium oxide on the first film mainly composed of a fluororesin;
Forming a first silane coupling agent film on the first film having the intermediate layer formed thereon;
Forming a second silane coupling agent film on a second film comprising as a main component one or more selected from the group consisting of polyethylene, polyester, and polycarbonate;
A method of manufacturing a composite structure, comprising: joining an intermediate layer on which the first silane coupling agent film is formed and a second film on which the second silane coupling agent film is formed. .   The method for producing a composite structure according to claim 1, wherein the first film and the second film have a visible light transmittance of 75% or more.   The method for producing a composite structure according to claim 1, wherein the intermediate layer is a titanium oxide film having a thickness of 2 nm to 1000 nm.