JP2011127199A - Transparent body and method for producing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent body with a hard coat structure having an ultraviolet shielding function and having high resistance to acid rain. <P>SOLUTION: The transparent body includes a transparent base material 1, and an ultraviolet absorption layer 2 and a hard coat layer 3 arranged on the base material 1 in order, and, as the ultraviolet absorption layer 2. an amorphous TiO<SB>2</SB>film is used. In the space between the ultraviolet absorption layer 2 and the hard coat layer 3, a mixed layer 4 made of a mixture between the amorphous TiO<SB>2</SB>and the material composing the hard coat layer is disposed. The TiO<SB>2</SB>film shows high acid resistance, and further, the amorphous TiO<SB>2</SB>film does not include photocatalytic performance, thus its adhesion with the base material is high. The mixed layer 4 increases the adhesion between the ultraviolet absorption layer 2 and the hard coat layer 3, and prevents film peeling in the case it is subjected to a thermal cycle. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a transparent body having a hard coat structure on a substrate, and particularly to a transparent body having a hard coat structure having an ultraviolet shielding function.

  Conventionally, a transparent member such as a lens is provided with a hard coat layer in order to prevent scratches and cracks on the surface. As the hard coat layer, a silicon oxide (SiOx) thin film is generally used.

In addition, when the base material of the transparent member is made of polycarbonate (hereinafter referred to as PC), since the PC has a property of yellowing by ultraviolet rays having a wavelength of 250 to 360 nm, a layer for shielding ultraviolet rays is provided separately from the hard coat layer. Need to prevent yellowing. As the layer for shielding ultraviolet rays, an ultraviolet absorbing layer made of a metal oxide thin film such as zinc oxide (ZnO) is used. ZnO is a semiconductor having a band gap of about 3.3 eV and absorbs ultraviolet rays of about 380 nm or less, and can prevent yellowing of PC with a film thickness of several thousand angstroms. In addition, an ITO (indium tin oxide) film, a TiO ₂ film, or the like can be used. The ZnO film is formed by vacuum deposition or coating such as ion plating or sputtering.

  When the ultraviolet absorbing layer and the hard coat layer are used in combination, the ultraviolet absorbing layer is disposed on the transparent substrate, and the hard coat layer is provided as the uppermost layer. A hard coat having such a two-layer structure and an ultraviolet shielding function is disclosed in, for example, Patent Document 1. However, when a hard coat structure composed of two layers of an ultraviolet absorbing layer (ZnO film) and a hard coat layer is provided on the PC substrate, the hard coat structure is easily peeled off from the interface between the PC substrate and the ZnO film. Therefore, Patent Document 2 proposes that a buffer layer is inserted between the PC base material and the ZnO film so that the hard coat structure has three layers. For example, a silicon oxide (SiOx) film is disclosed as the buffer layer.

  Patent Document 3 discloses a transparent laminated layer that is transparent, blocks ultraviolet rays, and has high weather resistance by forming a titanium oxide layer containing carbon at a predetermined ratio on a transparent substrate as a protective film. It is disclosed that the body can provide. In Patent Document 3, the titanium oxide layer contains carbon at a predetermined ratio because the photocatalytic ability of the titanium oxide causes the base material to change in quality, and the transparency of the base material deteriorates or the titanium oxide layer peels off. This is to prevent it from becoming easy.

  A hard coat structure composed of two layers of an ultraviolet absorbing layer and a hard coat layer is used, for example, in an automobile headlamp. The structure of the headlamp is such that a PC lens is hermetically bonded to the front surface of the housing to which the lamp is fixed as described in Patent Document 4. The incident light on the inner wall of the lens is limited to the light from the lamp, and does not include the wavelength that causes the PC lens to turn yellow. Therefore, no ultraviolet absorbing layer is required on the inner wall of the lens. Therefore, by providing a laminated structure of an ultraviolet absorbing layer and a hard coat layer on the outer wall of the lens where sunlight enters, even if the lens substrate is a PC, scratches and damage can be prevented, and yellowing can be prevented. can do.

JP-A-7-267683 JP 2008-105313 A JP 2008-45160 A JP 2000-207908 A

  Since automobile headlamps may be exposed to acid rain, the lenses are required to have acid resistance. However, a zinc oxide (ZnO) film used as an ultraviolet absorbing layer has a property of being weak against acids. Although the ultraviolet absorbing layer is covered with a silicon oxide (SiOx) film, which is a hard coat layer, the silicon oxide film has a slight water permeability, and part of the acid reaches the zinc oxide film. Sometimes. In this case, the portion where the acid has reached disappears as the zinc oxide film dissolves, and loses the yellowing prevention ability of the PC substrate. On the other hand, it is very difficult to form a transparent hard coat layer having no water permeability so that an acid does not reach the zinc oxide film.

  Further, in order to form a titanium oxide layer containing carbon at a predetermined ratio as in Patent Document 3, it is necessary to form a film by a plasma CVD method using an organic titanium compound as a raw material. However, since the organic titanium compound is expensive, it is difficult to realize a low-cost hard coat structure.

  The headlamp may be exposed to an environment such as high temperature and high humidity or low temperature drying depending on the place of use of the automobile. There is also the possibility of repeated exposure to such an environment. For this reason, as a hard coat for headlamps, resistance to temperature changes is also desired.

  An object of the present invention is to provide a transparent body having a hard coat structure having an ultraviolet shielding function and excellent resistance to acid rain and temperature change.

In order to achieve the above object, according to the first aspect of the present invention, the following transparent body is provided. A transparent body having a transparent substrate and an ultraviolet absorbing layer and a hard coat layer arranged in order on the substrate, and an amorphous TiO ₂ film is used as the ultraviolet absorbing layer. A mixed layer made of a mixture of amorphous TiO ₂ and a material constituting the hard coat layer is disposed between the ultraviolet absorbing layer and the hard coat layer. The TiO ₂ film has high acid resistance, and the amorphous TiO ₂ film does not have photocatalytic performance, and therefore has high adhesion to the substrate. The mixed layer improves adhesion between the ultraviolet absorbing layer and the hard coat layer, and prevents film peeling when subjected to a cooling and heating cycle.

It is desirable that the amorphous TiO ₂ film does not contain microcrystals.

  The thickness of the mixed layer is preferably 8000 angstroms or more. Thereby, film peeling when subjected to a predetermined cooling / heating cycle can be prevented.

According to the 2nd aspect of this invention, the manufacturing method of the following transparent bodies is provided. That is, the step of generating direct current plasma with a plasma gun, and heating and evaporating TiO ₂ or Ti filled in the crucible, passing the direct current plasma and depositing it on the transparent substrate, thereby making amorphous TiO _2. The step of forming a layer and the introduction of siloxane into the DC plasma while heating and evaporating TiO ₂ or Ti filled in the crucible, the amorphous TiO ₂ and SiO on the amorphous TiO ₂ film. a step of forming a mixed layer comprising a mixture of _{y (0 <y),} on the mixed layer, a method for producing a transparent body having a step of forming a SiO _x (0 _<x) layer. Thus, by forming a TiO ₂ film using DC plasma, an amorphous TiO ₂ film and a mixed film can be easily formed using TiO ₂ as an evaporation source.

  In the film formation step of the mixed layer, the film formation rate is preferably set to 15 angstrom / sec or more and 50 angstrom / sec or less.

In the step of forming the amorphous TiO ₂ layer, it is desirable to maintain the transparent substrate at a temperature of 150 ° C. or lower.

According to the present invention, by using an amorphous TiO ₂ film as an ultraviolet absorption layer, it is possible to provide a transparent body having a hard coat structure highly resistant to acid rain, ultraviolet rays, and temperature changes.

It is sectional drawing which shows the structure of the transparent body of embodiment. It is a block diagram of the film-forming apparatus used for manufacture of the transparent body of embodiment. In an embodiment, it is a graph which shows the spectral transmittance of hard coat layer 3 formed by changing the amount of oxygen introduced. It is a block diagram of the film-forming apparatus of another structure which can be used for manufacture of the transparent body of embodiment. Is a graph showing the X-ray diffraction measurements of amorphous TiO ₂ film formed in Example. It is a graph which shows the thermal cycle of the cold-heat cycle property test done with respect to the transparent sample of an Example. It is a graph which shows the spectral transmittance of the transparent body sample of an Example.

  An embodiment of the present invention will be described with reference to the drawings.

  First, the structure of the transparent body of this embodiment is demonstrated using FIG. The transparent body of the present embodiment includes a PC (polycarbonate) base material 1 and a hard coat structure 5 for protecting it from scratches and damage. The hard coat structure 5 is a PC base material. 1 has the function of shielding the ultraviolet rays that turn yellow. Examples of such a transparent body include a headlamp PC lens, a spectacle PC lens, a building material such as a window using a PC, and an automobile window using a PC. Is not limited to these, but can be applied to transparent bodies for other purposes.

Specifically, the hard coat structure 5 is a three-layer structure of an ultraviolet absorbing layer 2, a mixed layer 4, and a hard coat layer 3 that are sequentially laminated on the substrate 1 as shown in FIG. 1. The material of the ultraviolet absorbing layer 2 is amorphous TiO ₂ . It is desirable that amorphous TiO ₂ does not contain microcrystals. By using an amorphous TiO ₂ film as the ultraviolet absorbing layer 2, since the TiO ₂ film does not have photocatalytic performance, the adhesion to the PC base material 1 is high, and the phenomenon that the photocatalytic performance deteriorates the PC base material 1 is also caused. Can be suppressed.

The film thickness of the ultraviolet absorbing layer (amorphous TiO ₂ film) 2 is desirably set to a value larger than 1.0 μm. We, when provided with a TiO ₂ film in the PC substrate 1 as the ultraviolet absorbing layer 2, a result of the previously measured transmittance of the ultraviolet absorbing layer 2 to not cause yellowing PC substrate 1, wavelength It is visually confirmed that yellowing does not occur when the transmittance at 350 nm is less than 30%. On the other hand, the film thickness of the amorphous TiO ₂ film and the transmittance at a wavelength of 350 nm have a relationship as shown in Table 1. From Table 1, it is desirable to set the film thickness of the ultraviolet absorbing layer (amorphous TiO ₂ film) 2 to a value larger than 1.0 μm because the transmittance can be made smaller than 30%.

The film thickness of the ultraviolet absorbing layer (amorphous TiO ₂ film) 2 is desirably 3.0 μm or less. The reason is that, when the film thickness exceeds 3.0 μm, the absorption rate of TiO ₂ having a wavelength of 350 nm is saturated in the vicinity of 2%, so that even if the film thickness exceeds 3.0 μm, the ultraviolet absorption ability does not increase. Because. Moreover, since the adhesiveness with the base material 1 made from PC or the hard-coat layer 3 falls from the thickness exceeding 3.0 micrometers, and it becomes easy to peel, it is preferable that it is 3.0 micrometers or less in film thickness.

  The material of the hard coat layer 3 is SiOx. x is preferably 1.5 <x <2.0.

  The film thickness of the hard coat layer (SiOx film) 3 is preferably 1000 angstroms or more, and more preferably 5000 angstroms or more and 10 μm or less in order to generate hardness that can function as a hard coat.

The mixed layer 4 is disposed to improve the adhesion between the ultraviolet absorbing layer 2 and the hard coat layer 3 and prevent the hard coat layer 3 from being peeled off from the ultraviolet absorbing layer 2 when a cooling cycle is applied. . The mixed layer 4 is composed of a mixture of TiO ₂ and SiO _y . The TiO ₂ constituting the mixed layer 4 is desirably amorphous. The y value of SiO _y constituting the mixed layer 4 is preferably y <2.

The ratio of TiO ₂ and SiO _y constituting the mixed layer 4 is preferably 1: 1. The film thickness of the mixed layer 4 is desirably 8000 angstroms or more.

Next, the function of each layer of the hard coat structure 5 will be described. The hard coat layer 3 is disposed on the outermost layer in order to prevent the substrate 1 from being scratched or cracked. The amorphous TiO ₂ film constituting the ultraviolet absorbing layer 2 has a band gap of 3.0 to 3.3 eV, and has a property of absorbing ultraviolet light of around 380 nm or less. Therefore, by arranging an amorphous TiO ₂ film between the hard coat layer 3 and the substrate 1 as the ultraviolet absorption layer 2, ultraviolet rays having a wavelength of 250 to 360 nm that cause yellowing of the PC substrate 1 are absorbed by the ultraviolet absorption layer. 2 can be absorbed.

Since the ultraviolet absorbing layer 2 made of an amorphous TiO ₂ film not containing microcrystals does not have photocatalytic performance, even if it is directly disposed on the PC substrate 1, high adhesion can be obtained. The structure 5 can be firmly arranged on the substrate 1. Moreover, since it does not have photocatalytic performance, the PC base material is not deteriorated by the photocatalytic performance.

The ultraviolet absorbing layer 2 that is an amorphous TiO ₂ film has high adhesion to the hard coat layer 3, but in order to further improve the adhesion between the two when a temperature change is applied, the ultraviolet absorbing layer 2 and the hard coating layer 3 are hardened. A mixed layer 4 is disposed between the coating layer 3 and the coating layer 3. Thereby, when a temperature change is added, it can prevent that the hard-coat layer 3 peels from the ultraviolet absorption layer 2. FIG.

A TiO ₂ film is known to have high acid resistance. This property does not change even with an amorphous TiO ₂ film. Therefore, even when acid rain penetrates into the hard coat layer (SiOx film) 3, the ultraviolet absorbing layer (amorphous TiO ₂ film) 2 and the mixed layer 4 do not dissolve and disappear, and the PC substrate The ability to prevent yellowing can be continuously exhibited.

  Below, the manufacturing method of the transparent body of this embodiment is demonstrated. In this case, the transparent hard coat structure 5 is formed by a direct current plasma assist ion plating method using a direct current plasma and a chemical vapor deposition (CVD) method using the film forming apparatus of FIG. 2 using direct current plasma. Form continuously.

  The film forming apparatus shown in FIG. 2 includes a plasma gun 31 and a film forming chamber 7. In the film forming chamber 7, an anode electrode 38 is disposed at a position facing the plasma gun 31, and DC plasma is generated from the plasma gun 31 toward the anode electrode 38. Between these, a reaction gas introduction pipe 8 and a crucible 33 for introducing the reaction gas 37 are provided. A base material holder 36 for holding the base material 1 is provided at a position facing the reaction gas introduction pipe 8 and the crucible 33. The crucible 33 includes an electron gun 133 and heats the evaporation source 34 with an electron beam (EB). A power source 10 is connected to each of the plasma gun 31 and the anode electrode 38. The electromagnets 12 are arranged outside the plasma gun 31 and outside the film forming chamber 7 so that the central axes thereof coincide with each other. The electromagnet 12 acts to converge the plasma 35 generated by the plasma gun 31 into a beam shape.

The manufacturing method of a transparent body is demonstrated. First, an ultraviolet absorbing layer (TiO ₂ film) 2 is formed by a direct current plasma assist ion plating method. The crucible 33 is filled with Ti. After the substrate 1 is set on the substrate holder 36 and the film formation chamber 7 is evacuated to a predetermined pressure, a carrier gas 32 is introduced into the plasma gun 31 and plasma 35 is generated between the anode electrode 38. In this state, the electron beam 133 is irradiated onto the Ti 34 from the electron gun 133 of the crucible 33 and is heated and evaporated. Further, oxygen gas is introduced from the reaction gas introduction tube 37, and the plasma 35 is changed to a mixed plasma of carrier gas and oxygen. As a result, Ti evaporated from the crucible 33 is oxidized by passing through the mixed plasma, and is deposited on the substrate 1 to form a TiO ₂ film (DC plasma assisted ion plating method).

In the DC plasma assist ion plating method, the amorphous TiO ₂ film (ultraviolet absorption layer) 2 can be easily formed using Ti as an evaporation source by maintaining the substrate temperature at 150 ° C. or lower. The other film formation conditions are preferably set to, for example, a film formation speed of 5000 angstrom / min or less and a DC discharge power of 10 kW or less. However, the film formation conditions except for the substrate temperature are not limited to these film formation conditions.

Subsequently, the mixed layer 4 is formed. After the ultraviolet absorbing layer 2 is formed, heating of the Ti 34 in the crucible 33 by the electron gun 133 and generation of the plasma 35 are continued without opening the film forming chamber 7. In this state, siloxane is introduced from the reaction gas introduction pipe 8 in addition to the oxygen gas. As a result, the ion plating and the polymerization reaction proceed simultaneously to form the mixed layer 4 of TiO ₂ and SiO _y .

At this time, the film formation rate of the entire mixed layer 4 is desirably 15 to 50 angstrom / sec. By forming the film at such a film formation speed, when the mixed layer 4 is formed under a constant pressure, the ratio of TiO ₂ and SiO _y in the mixed layer 4 can be made substantially 1: 1. The amount of oxygen gas introduced is preferably set to be less than 70 sccm. Thereby, the y value of SiOy of the mixed layer 4 can be set to y <2. The substrate temperature is desirably 150 ° C. or lower. Accordingly, the TiO ₂ mixed layer 4 can be made amorphous.

As the vapor deposition source, TiO ₂ can be used. However, when Ti is used as the vapor deposition source, the Ti evaporation rate can be easily controlled.

  Subsequently, a hard coat layer 3 is formed. After the mixed layer 4 is formed, the generation of the electron beam of the electron gun 133 is stopped and the generation of the plasma 35 is continued without opening the film formation chamber 7. Siloxane is introduced as a reaction gas 37 from the reaction gas introduction pipe 8 to cause a polymerization reaction, and SiOx is deposited on the substrate 1 to a predetermined thickness. This is a so-called plasma CVD method. Thereby, a hard coat layer (SiOx layer) 3 is formed. However, the hard coat layer 3 is formed in the predetermined film thickness described above in order to exhibit the function as a hard coat.

Further, if the hardness of the hard coat layer 3 is further improved, it is preferable to introduce oxygen together with siloxane as a reaction gas to promote the oxidation reaction. However, in the case where the film is formed on the resin base material 1 as in the present embodiment, if the hard coat layer 3 is too hard as compared with the base material 1, the thermal cycle resistance is inferior. FIG. 3 shows measurement results of the spectral transmittance of the hard coat layer 3 when only the hard coat layer 3 is formed under the same conditions using hexamethyldisiloxane. When only hexamethyldisiloxane is formed without introducing oxygen, light in the wavelength range of 200 nm to 300 nm is hardly transmitted, and a transmittance of 90% or more is exhibited in the long wavelength range of 430 nm to 800 nm. When a film is formed by introducing 300 sccm of oxygen as a reaction gas, a flat region having a transmittance of 90% or more in a wide wavelength region of 200 nm to 800 nm is shown. In addition, the hardness was higher in the case where oxygen was introduced than in the case where oxygen was not introduced. That is, when oxygen of at least 300 sccm or more is introduced, it is presumed that it is SiO ₂ . In the present embodiment, the heat cycle resistance is emphasized, and oxygen is not introduced when the hard coat layer 3 is formed, and the film is formed under the condition of the SiO _x film (x <2).

  By the above, the transparent body provided with the hard coat structure 5 of the three-layer structure on the base material 1 as shown in FIG.

Here, although the ultraviolet absorbing layer 2, the mixed layer 4, and the hard coat layer 3 were formed using the film forming apparatus of FIG. 2, the present invention is not limited to this film forming method. For example, the same result can be obtained even when the film forming apparatus shown in FIG. 4 is used to form a film by vacuum vapor deposition and chemical vapor deposition (CVD). 4 does not include the electron gun 133 of the apparatus of FIG. 2, but a voltage is applied to the crucible 33 and a part of the direct current plasma is guided to the crucible 33 to heat the evaporation source 34. In the case of the apparatus of FIG. 4, TiO ₂ is used as the evaporation source 34. Moreover, although it is inferior in the point of the continuous film-forming in the same film-forming apparatus, it will also be possible to form each layer in order by a coating method or other vapor phase growth methods, for example.

As described above, the transparent body of the present embodiment improves the acid resistance by using a TiO ₂ film as the ultraviolet absorbing layer 2, and has a photocatalytic performance by making TiO _{2 an} amorphous structure that does not contain microcrystals. Without causing it, adhesion to the PC base material can be improved, and deterioration of the PC base material due to photocatalytic performance can be prevented. Therefore, the hard coat layer 3 can prevent the substrate 1 from being scratched or damaged while the ultraviolet absorbing layer 2 prevents yellowing of the PC substrate 1.

  Further, since the mixed layer 4 is disposed between the ultraviolet absorbing layer 2 and the hard coat layer 3, the hard coat layer 3 is peeled off from the ultraviolet absorbing layer 2 even when used in an environment with a large temperature change. The durability can be improved without any problems.

In addition, in this embodiment, by using DC plasma, the amorphous TiO ₂ film (ultraviolet absorption layer 2) and the mixed layer 4 can be easily formed using Ti or TiO ₂ as an evaporation source, which is expensive. There is no need to use a material, and the hard coat structure 5 having excellent acid resistance can be formed at low cost.

  The structure of the transparent body of this embodiment can be applied to building materials such as a PC lens for a headlamp, a PC lens for spectacles, a window using a PC, and a window using a PC of an automobile. For example, when used in an automobile headlamp, the hard coat structure 5 of the present embodiment can be applied to a PC lens hermetically bonded to the front surface of a housing to which the lamp is fixed. That is, the hard coat structure 5 can be provided on the surface of the PC lens as the base material 1. The incident light on the inner wall of the PC lens is limited to the light from the lamp, and does not include the ultraviolet wavelength that causes the PC lens to turn yellow. Therefore, no ultraviolet absorbing layer is required on the inner wall of the lens. Therefore, the hard coat structure 5 of the present embodiment is provided on the outer wall of the lens on which sunlight or the like is incident. Thereby, even if a lens base material is PC, a damage | wound and damage can be prevented, and also yellowing can be prevented.

Hereinafter, an embodiment of the present invention will be described.
In this example, a transparent body having the structure shown in FIG. 1 was produced. The material of the ultraviolet absorption layer 2 is amorphous TiO ₂ that does not contain microcrystals. The material of the hard coat layer 3 is SiOx (1.5 <x <2.0). The material of the mixed layer 4 is amorphous TiO ₂ and SiOy (y <2.0). The substrate 1 is a PC and has a plate shape with a thickness of 3 mm.

Film formation of each layer was performed using the film formation apparatus of FIG. 2 according to the manufacturing procedure described in the embodiment. He was used as the carrier gas 32. This is because abnormal discharge around the electron gun can be suppressed as compared with the case where Ar is used as the carrier gas 32. Ti was used as the evaporation source. During the film formation of the ultraviolet absorbing layer 2, 50 sccm of oxygen gas was introduced, and the pressure of the film forming apparatus was 3 × 10 ⁻¹ Pa. When the mixed layer 4 was formed, hexamethyldisiloxane was introduced while being controlled by a needle valve while oxygen gas was introduced at 50 sccm. The amount of hexamethyldisiloxane introduced was adjusted so that the pressure of the film forming apparatus when the carrier gas (He) 32, oxygen gas, and hexamethyldisiloxane were introduced was 1.3 to 2.0 Pa. The deposition rate of the ultraviolet absorbing layer 2 was 4000 angstrom / min, and the DC discharge power was 4.5 KW. The evaporation rate of Ti and the introduction amount of hexamethyldisiloxane were adjusted so that the film formation rate of the mixed layer 4 was 15 to 50 Å / sec. Further, when the mixed layer 4 was formed, the ratio of the amount of evaporated Ti and the amount of introduced hexamethyldisiloxane were adjusted so that the ratio of Ti: Si was approximately 1: 1. When the ultraviolet absorbing layer 2 and the mixed layer 4 were formed, the substrate 1 was not heated, and the temperature of the substrate 1 was controlled to be 150 ° C. or lower. When the hard coat layer 3 was formed, the supply of oxygen gas was stopped and hexamethyldisiloxane was introduced. The amount of hexamethyldisiloxane introduced was adjusted so that the pressure of the film forming apparatus when the carrier gas (He) and hexamethyldisiloxane were introduced was 1.3 to 2.0 Pa.

When the crystal structure of the ultraviolet absorbing layer (TiO ₂ film) 2 formed under the same film forming conditions as in this example was measured by X-ray diffraction, the diffraction intensity was broad and amorphous as shown in FIG. Was confirmed. The film of the ultraviolet absorbing layer 2 was heat-treated at 600 ° C. for 30 minutes and then measured by X-ray diffraction. As a result, an anatase TiO ₂ crystal peak was confirmed. From this, it was confirmed that the TiO ₂ of the ultraviolet absorbing layer 2 that was not heat-treated was amorphous. Similarly, when the crystal structure of the mixed layer 4 was measured by X-ray diffraction, the diffraction intensity was broad like the ultraviolet absorbing layer 2. Therefore, TiO _{2 of the} mixed layer 4 is also assumed to be amorphous because it is the same as the film forming conditions of the ultraviolet absorbing layer 2. Further, the mixed layer 4 formed under the same conditions as the mixed layer 4 having a film thickness of 8000 angstrom, which was evaluated for the thermal cycle resistance described later, was analyzed by X-ray photoelectron spectroscopy. As a result, the ratio of TiO ₂ and SiO _y was 1: 1.

<Evaluation>
(Acid resistance)
In order to confirm the acid resistance of the transparent ultraviolet absorbing layer 2 of this example, the mixed layer 4 is not provided, but the ultraviolet absorbing layer (amorphous TiO ₂ ) 2 and the hard coat layer (SiOx) 3 are provided on the substrate 1. The sample for evaluation provided only with was produced. The film thickness of the ultraviolet absorbing layer 2 was 2 μm, and the film thickness of the hard coat layer 3 was 0.5 μm, 1 μm, 1.5 μm, 2.0 μm, and 2.5 μm as shown in Table 2.

  As a comparative example, a sample having only the ultraviolet absorption layer 2 without the hard coat layer 3 was produced. Table 2 shows a sample having a hard coat layer 3 having a thickness of 0 μm.

Further, as a comparative example, the ultraviolet absorbing layer is an In ₂ O ₃ film (thickness 0.5 μm), and the hard coat layer 3 is an SiOx film (film thickness: 0 μm, 0.5 μm, 1 μm, 1.5 μm, 2.0 μm, A comparative sample having a thickness of 2.5 μm was manufactured.

  As yet another comparative example, a SiOx layer (thickness 0.5 to 1 μm) is disposed as a buffer layer on the PC substrate 1, and then a ZnO film (thickness 0.2 μm) is formed as an ultraviolet absorbing layer. A comparative example sample in which a SiOx film (film thickness: 0 μm, 0.5 μm, 1 μm, 1.5 μm, 2.0 μm, 2.5 μm) was formed as the hard coat layer 3 was produced. The reason why the buffer layer is arranged under the ZnO film is that when the ZnO film is directly formed on the PC substrate 1, it is easy to peel off as shown in Table 3 to be described later, and it becomes difficult to perform an acid resistance test. is there.

  The comparative sample was manufactured in the same manner as in this example using the film forming apparatus shown in FIG.

The acid resistance test was performed by dropping 0.2 ml of a 0.1 N H ₂ SO ₄ solution onto the hard coat structure 5 of the sample of the example and the comparative example, leaving it to stand for 24 hours, washing it with water, and then leaving it for another hour. It was. After the test, the state of the substrate was visually observed and evaluated. The results are shown in Table 2.

From Table 2, in the comparative example using the ZnO film as the ultraviolet absorbing layer, all the ZnO film disappeared regardless of the film thickness of the hard coat layer (SiOx film) 3, and 0.1N H ₂ it was found that there is no acid resistance against SO _4.

Comparative examples using _In 2 _{O 3} film as the ultraviolet absorbing layer, a hard coat layer as long as the thickness of the (SiOx film) 3 is 2μm or more, but _In 2 _{O 3} film is not lost, if thinner than 2μm Shows that the In ₂ O ₃ film disappears.

In contrast, in the sample using the amorphous TiO ₂ film as the ultraviolet absorbing layer 2 of the present example, the amorphous TiO ₂ film does not disappear regardless of the film thickness of the hard coat layer (SiOx film) 3. I understand. Furthermore, even in the comparative example not including the hard coat layer (SiOx film) 3 (0 μm), the amorphous TiO ₂ film is not lost.

From this, the amorphous TiO ₂ film as the ultraviolet absorbing layer 2 is very excellent in acid resistance compared to the In ₂ O ₃ film and the ZnO film, and does not dissolve regardless of the water permeability of the hard coat layer 3. confirmed. Therefore, even when it is exposed to acid rain, it can continue to exhibit ultraviolet absorption performance without disappearing, and yellowing of the PC substrate 1 can be prevented.

(Adhesion)
In order to measure the adhesion between the transparent ultraviolet absorbing layer 2 of this example and the substrate made of PC, an evaluation sample having only the ultraviolet absorbing layer (amorphous TiO ₂ ) 2 on the substrate 1 was prepared. did. The film thickness of the ultraviolet absorbing layer 2 was 2000 angstroms.

As a comparative example, a sample in which an In ₂ O ₃ film (film thickness 2000 angstrom) is disposed on a PC substrate and a sample in which a ZnO film (film thickness 2000 angstrom) is disposed on a PC substrate are formed by vapor deposition. In the same manner, the adhesion was measured.

  The adhesion was measured by a gobang eye test according to JIS D0202 8.12.

As a result, as shown in Table 3, the adhesion between the PC substrate 1 of the example and the amorphous TiO ₂ film (ultraviolet absorption layer 2), and the comparison between the PC substrate and the In ₂ O ₃ film of the comparative example. The Gobang eye test results were all 1 and it was found that these adhesions were good. On the other hand, the result of the Gobang eye test of the PC base material of the comparative example and the ZnO film was 4, and the adhesion was low. Thereby, it was confirmed that the amorphous TiO ₂ film (ultraviolet absorption layer 2) has high adhesion to the PC base material and does not cause film peeling. Therefore, it is not necessary to arrange a buffer layer or the like between the PC base material and TiO _2, and the manufacturing process can be simplified.

(Cool and heat cycle resistance)
In order to confirm the heat and heat cycle resistance of the ultraviolet absorbing layer 2 of the transparent body of this example, the mixed layer 4 has a plurality of kinds of film thicknesses in the three-layer structure of the ultraviolet absorbing layer 2, the mixed layer 4, and the hard coat layer 3. A sample for evaluation was prepared. The film thickness of the ultraviolet absorbing layer 2 was 1.0 μm, and the film thickness of the hard coat layer 3 was 2.0 μm.

  These samples for evaluation were subjected to a test in which 10 cycles of thermal cycles varying from −40 ° C. to 80 ° C. (humidity 90%) as shown in FIG. 6 over 8 hours were performed, and the state of the film was visually observed. did.

  As shown in Table 4, it was confirmed that when the thickness of the mixed layer 4 was 8000 angstroms or more, a hard coat that would not be peeled off in the thermal cycle resistance test could be obtained.

(Spectral transmission)
Furthermore, the hard coat structure 5 of this example (a laminated body of an amorphous TiO ₂ film (thickness 2.0 μm), a mixed layer 4 (thickness 8000 angstroms), and a SiOx film (thickness 1.0 μm)). When the spectral transmittance was measured, the transmittance at 350 nm was 20% or less as shown in the graph of FIG. 7, and the condition that the transmittance at 350 nm to prevent yellowing of the PC substrate 1 was 30% or less was satisfied. As is apparent from the graph of FIG. 7, the hard coat structure of the example has a higher ultraviolet transmittance than the sample in which the ZnO film is formed as the ultraviolet absorbing layer 2, but sufficient yellowing prevention performance can be obtained.

The reason why an amorphous TiO ₂ film can provide sufficient yellowing prevention performance even if its ultraviolet transmittance is higher than that of a ZnO film is not clear at this time. The sample using the amorphous TiO ₂ film of the example was subjected to an accelerated ultraviolet irradiation test (a test in which light having a wavelength of 295 to 450 nm and an intensity of 100 mw / cm ² was irradiated for 72 hours), and confirmed that yellowing did not occur. ing.

DESCRIPTION OF SYMBOLS 1 ... PC base material, 2 ... Ultraviolet ray prevention layer, 3 ... Hard coat layer, 4 ... Mixed layer, 5 ... Hard coat structure, 7 ... Deposition chamber, 8 ... Reactive gas introduction pipe, 10 ... Power supply, 12 ... Electromagnet, 31 ... plasma gun, 32 ... carrier gas, 33 ... crucible, 34 ... vapor source _TiO 2, 35 ... plasma, 36 ... substrate holder, 37 ... reaction gas, 38 ... anode electrode.

Claims (6)

A transparent base material, and an ultraviolet absorbing layer and a hard coat layer disposed in order on the base material;
The ultraviolet absorbing layer is an amorphous TiO ₂ film,
A transparent body, wherein a mixed layer made of a mixture of amorphous TiO ₂ and a material constituting the hard coat layer is disposed between the ultraviolet absorbing layer and the hard coat layer. The transparent body according to claim 1, wherein the amorphous TiO ₂ film does not contain microcrystals.   The transparent body according to claim 1 or 2, wherein the mixed layer has a thickness of 8000 angstroms or more. Generating DC plasma with a plasma gun;
A step of forming an amorphous TiO ₂ layer by heating and evaporating TiO ₂ or Ti filled in the crucible, passing the DC plasma, and depositing it on a transparent substrate;
By introducing siloxane into the DC plasma while heating and evaporating TiO ₂ or Ti filled in the crucible, amorphous TiO ₂ and SiO _y (0 <y) are formed on the amorphous TiO ₂ film. A step of forming a mixed layer containing a mixture of
Forming a SiO _x (0 <x) layer on the mixed layer.   5. The method for producing a transparent body according to claim 4, wherein in the film forming step of the mixed layer, a film forming speed is set to 15 angstrom / sec or more and 50 angstrom / sec or less. . In the manufacturing method of the transparent body according to claim 4 or 5,
In the film formation step of the amorphous TiO ₂ layer, the transparent substrate is maintained at a temperature of 150 ° C. or lower.

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