Manufacturing method for transparent laminates

Abstract

Provided is a method for producing a see-through or daylighting, transparent multilayered product for use as the windshield of a transport machine such as a vehicle, e.g., a motor vehicle or a railroad car, an air plane, or a ship. A silicone-based resin layer 3 is formed over a resinous base 1. A polysilazane mixture obtained by mixing an organopolysilazane and a perhydropolysilazane so that the solid proportion of the former to the latter, O / P, is 1-25 wt% is applied to the surface of the silicone-based resin layer 3 and cured to form a polysilazane mixture layer 4. The coated resinous base 1 is irradiated from above the polysilazane mixture layer 4 with vacuum ultraviolet light having a wavelength of 200 nm or less, thereby modifying the silicone-based resin layer through the polysilazane mixture layer 4 to convert some thereof into a silicon dioxide film.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a transparent laminate used for visibility or light transmission, which is used as a windbreak for vehicles such as automobiles and railways, airplanes, ships, and other transportation equipment. [Background technology]

[0002] Windshields for vehicles such as automobiles and trains, as well as aircraft and ships, are used in environments exposed to the outdoors or subjected to continuous friction by wipers. Resin substrates such as polycarbonate are lighter than glass substrates and are expected to replace glass substrates as window materials for transparency and light transmission. While resin substrates have excellent moldability, their surfaces are very easily scratched. Therefore, to enable resin substrates to be used in harsh environments such as windshields, a modified film mainly composed of silicon dioxide is formed on the resin substrate to improve scratch resistance. This modified layer is formed by applying acrylic resin or a hard coat to the surface of the resin substrate to form a hard thin film.

[0003] For example, according to Patent Document 1, a modified film mainly composed of silicon dioxide is formed by applying a siloxane resin by a dip coating method and irradiating its surface with vacuum ultraviolet light. According to the same document, a problem is disclosed in which cracks occur when the thickness of the modified film is increased to 0.6 μm or more.

[0004] According to Patent Document 2, a laminate is disclosed for use as a window material for vehicles, in which a hard coat layer (I) containing a siloxane-based polymer component and an organic polymer component is laminated on a plastic substrate, and a silica film (II) converted from polysilazane is further formed on the hard coat layer (I). Polysilazane is an inorganic polymer soluble in organic solvents, with -(SiH2NH)- as its basic unit.

[0005] In the laminate described in the patent document, the hard coat layer (I) is formed such that a relatively large amount of siloxane polymer components are present on the side in contact with the silica film (II), and a relatively large amount of organic polymer components are present on the substrate side. The formation of such a hard coat layer (I) is performed by curing the hard coat layer by irradiation with active energy rays after application. The formation of the silica film (II) is performed by applying a polysilazane-containing coating composition. By having a relatively large amount of siloxane polymer components on the side in contact with the silica film (II), the adhesion to the silica film (II) is improved.

[0006] Patent Document 3 describes a technology for flexible gas barrier films used in electronic devices such as solar cells and liquid crystals. This technology involves applying a coating solution containing a polysilazane composition onto an adjacent layer, followed by modification treatment by vacuum ultraviolet irradiation to form a barrier layer containing inorganic material. Furthermore, according to the same document, by providing an adjacent layer, silanol groups and the like are not generated in the polysilazane coating film before vacuum ultraviolet irradiation. Subsequent vacuum ultraviolet irradiation breaks the molecular bonds of the polysilazane, resulting in ceramicization (silica modification) of the coating film surface. It is stated that when the polysilazane layer thickness is 150 nm, a film is created in which a continuous region of approximately 5 to 100 nm (equivalent to SiO2 thermal oxide film) exists with a depth of 2 nm or more, where the ratio of Si, N, and O atoms is almost constant.

[0007] Furthermore, the same document states that perhydropolysilazane is particularly preferred as the polysilazane, and also suggests the use of a mixture of perhydropolysilazane and organopolysilazane. However, only examples of perhydropolysilazane are shown in the examples.

[0008] The method for manufacturing a transparent laminate according to Patent Document 4 involves applying a composition mainly composed of polysilazane to the surface of a silicone resin layer formed on a resin substrate, curing it to convert it to silica to form a cured polysilazane layer, and then irradiating the cured polysilazane layer with vacuum ultraviolet light with a wavelength of 200 nm or less, thereby modifying a portion of the silicone resin layer through the cured polysilazane layer into a modified silicon dioxide film. The gas volatilized by the irradiation of the silicone resin layer with vacuum ultraviolet light diffuses into the resin substrate due to the gas barrier properties of the cured polysilazane layer, improving crack and delamination performance in ultra-accelerated weathering tests (SUV) without roughening the surface or causing scratches.

[0009] The same document states that perhydropolysilazanes are preferable as polysilazanes, but also suggests the possibility of selecting organopolysilazanes. However, only examples of perhydropolysilazanes are shown in the examples.

[0010] Perhydropolysilazane is a polysilazane (also called PHPS) in which R1, R2, and R3 in the general formula (Chemical Formula 1) below are all hydrogen atoms. Furthermore, organopolysilazanes are polysilazanes (also called OPSZs) in which the hydrogen atoms bonded to Si in the following general formula (Chemical Formula 1) are partially replaced with alkyl groups, alkenyl groups, cycloalkyl groups, aryl groups, alkylsilyl groups, alkylamino groups, or alkoxy groups.

[0011] [ka] [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Patent No. 4536824 [Patent Document 2] Patent No. 6256858 [Patent Document 3] Japanese Patent No. 5935263 Publication

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0013] In Patent Document 4, by allowing vacuum ultraviolet rays to reach the interface between the cured polysilazane layer and the silicone-based resin layer to induce an interfacial reaction, a part of the silicone-based resin layer is modified into a silicon dioxide modified film through the cured polysilazane layer to improve adhesion. As a result, it has been shown that weather resistance and heat resistance are improved compared to the case where vacuum ultraviolet rays are irradiated onto a silicone-based resin layer not coated with polysilazane.

[0014] The applicant of the present application has conducted intensive studies to further improve weather resistance and heat resistance. Furthermore, in the above document, the recommended film thickness of polysilazane is 10 to 100 nm. Controlling the film thickness quality over a large area and curved surface of windshields for transportation equipment such as automobiles, railway vehicles, airplanes, and ships within such an extremely narrow range requires high costs, so this improvement has also been studied.

[0015] An object of the present invention is to provide a method for producing a transparent laminate for perspective or daylighting that is used as a windshield for transportation equipment such as automobiles, railway vehicles, airplanes, and ships.

Means for Solving the Problems

[0016] The method for producing a transparent laminate according to the present invention is characterized in that: A transparent laminate for a windbreak, wherein a silicone resin layer made of alkoxysilane-based siloxane resin is formed on a resin substrate, a mixed polysilazane in which organopolysilazane is mixed with perhydropolysilazane in a solid content ratio (O / P ratio) of 1 wt% to 25 wt% is applied to the surface of the silicone resin layer and cured to form a mixed polysilazane layer with a film thickness of 11 nm to less than 565 nm, and vacuum ultraviolet light with a wavelength of 200 nm or less is irradiated from above the mixed polysilazane layer at an irradiation dose of 2 J / cm². 2 More than 8J / cm 2 By irradiating as described below, the silicone resin layer is passed through the mixed polysilazane layer. a part of [the aforementioned layer] is modified into a silicon dioxide modified film.

Effects of the Invention

[0017] According to the present invention, it has been found that mixing organopolysilazane with perhydropolysilazane facilitates coating on silicone resin layers compared to the case of using organopolysilazane alone. Subsequently, the thickness of the mixed polysilazane layer was examined when vacuum ultraviolet rays with a wavelength of 200 nm or less were irradiated onto the coated and cured mixed polysilazane layer, and it was found that by setting the film thickness to less than 565 nm, a transparent laminate with excellent SUV weather resistance can be obtained. Since the range of the film thickness of the mixed polysilazane layer can be widened, it is possible to improve productivity and control the film thickness quality for large-area and curved windshields of transportation equipment such as vehicles including automobiles and railways, airplanes, and ships.

[0018] Furthermore, by setting the thickness of the polysilazane layer after ultraviolet irradiation to 100 to 300 nm, a transparent laminate excellent in SUV weather resistance can be obtained. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0019] [Figure 1] It is a diagram showing an example in which organopolysilazane is applied onto a silicone resin layer by spin coating. [Figure 2] It is a diagram schematically showing a cross-section of a transparent laminate produced by the modification method of the present invention. [Figure 3] It is a diagram showing the results of SUV weather resistance and heat resistance tests. [Figure 4] It is a diagram showing wear resistance test results when the O / P ratio is changed. [Figure 5] It is a diagram showing test results regarding the effect of a catalyst on SUV weather resistance. [Figure 6] It is a diagram showing test results regarding the effect of increasing the irradiation dose of vacuum ultraviolet rays. [Figure 7] It is a diagram showing the results of a heat resistance test, an SUV weather resistance test, and a Taber abrasion test for each film thickness. [DESCRIPTION OF THE PREFERRED EMBODIMENTS]

[0020] While perhydropolysilazanes form an inorganic coating, organopolysilazanes form an inorganic-organic hybrid coating. Because organopolysilazane coatings contain organic compounds, they are expected to have improved toughness compared to perhydropolysilazane inorganic coatings, and crack formation is anticipated to be suppressed even when the film thickness is increased.

[0021] Therefore, the inventors attempted to use organopolysilazane, as shown in Patent Document 4, by applying a composition mainly composed of organopolysilazane to the surface of a silicone resin layer formed on a resin substrate, curing it to convert it to silica to form a mixed polysilazane layer, and irradiating the mixed polysilazane layer with vacuum ultraviolet light of a wavelength of 200 nm or less, and evaluated the resulting samples.

[0022] Figure 1 shows an example of applying organopolysilazane to a silicone resin layer by spin coating. The silicone resin layer to be coated is a hard coat layer formed by applying a siloxane resin, obtained by hydrolyzing a siloxane sol obtained via a condensation reaction based on alkoxysilane, using a dip coating method and then curing it. The organopolysilazane used was 1033 from the DURAZANE 1000 series (DURAZANE is a registered trademark of Merck Komandeitgesellschaft auf Aktchen AG). DURAZANE 1033 is a liquid, low-viscosity, solvent-free resin.

[0023] According to Patent Document 3, organopolysilazanes have improved adhesion to the substrate due to the presence of alkyl groups such as methyl groups. However, in the applicant's tests, DURAZANE1033 was repelled and formed droplets, making it impossible to form a film. The samples tested were prepared by adding a solvent to undiluted DURAZANE1033 (Figure 1C, 100 wt%) to adjust the ratio of DURAZANE1033 to 25 wt% (Figure 1A) and 50 wt% (Figure 1B). Thus, it is actually difficult to apply organopolysilazanes to silicone resin layers. Figure 1D is the nominal chemical formula.

[0024] Next, the inventors found that mixing organopolysilazane with perhydropolysilazane made it easier to coat the silicone resin layer than with organopolysilazane alone. Even when the organic / inorganic ratio (O / P ratio) of organopolysilazane solids to perhydropolysilazane solids was adjusted to 3 times (100g of perhydropolysilazane solids to 300g of organopolysilazane solids), a film with a thickness of 100nm could be formed on the silicone resin layer by spin coating at 3000rpm (1 minute). The perhydropolysilazane used here is Tresmile #100-15 from Sanwa Chemical Co., Ltd. (Tresmile is a registered trademark of Sanwa Chemical Co., Ltd.).

[0025] Furthermore, using a sample containing a mixture of organopolysilazane and perhydropolysilazane (hereinafter referred to as mixed polysilazane), we investigated the process of coating the surface of a silicone-based resin layer formed on a resin substrate with the mixed polysilazane, curing it to convert it into silica, and then irradiating the mixed polysilazane layer with vacuum ultraviolet light of a wavelength of 200 nm or less to modify a portion of the silicone-based resin layer into a modified silicon dioxide film through the mixed polysilazane layer.

[0026] In Patent Document 4, it has been observed that when a silicone resin layer (hard coat layer) made of a polymer having siloxane bonds is formed and irradiated with vacuum ultraviolet light, the organic components of the polymer volatilize from the surface of the silicone resin layer, and the surface roughness of the modified film, which is mainly composed of silicon dioxide, increases. The initial surface roughness (Rmax) was 3 nm or less, but when the irradiation energy was 8400 mJ / cm², it increased. 2 When this is reached, the surface roughness (Rmax) exceeds 10 nm. Results from accelerated weathering (SUV) tests using metal halide lamps show that as the irradiation energy increases and the surface roughness increases, the time to cracking and delamination decreases. Reducing this surface roughness is one way to further improve SUV weather resistance.

[0027] When the mixed polysilazane was further applied to the surface of the comparative example before irradiation with vacuum ultraviolet light, the surface roughness was smoothed. Furthermore, even after irradiation with vacuum ultraviolet light, the surface roughness (Rmax) remained almost unchanged at 3 nm or less. Therefore, the inventors investigated whether using mixed polysilazane would improve weather resistance and heat resistance compared to using perhydropolysilazane alone (Patent Document 4), or whether, even if the weather resistance and heat resistance were similar, it would be possible to achieve a larger film thickness than the polysilazane film thickness (10-100 nm) recommended in Patent Document 4, thereby reducing the cost of quality control of the film thickness.

[0028] Figure 2 is a schematic diagram showing a cross-section of a transparent laminate 10 manufactured by the modification method of the present invention. It consists of a resin substrate 1, a primer layer 2 formed thereon, a silicone resin layer 3 formed thereon, and a mixed polysilazane layer 4 formed thereon.

[0029] There are no particular restrictions on the resin substrate 1, but suitable materials include resins such as acrylic resin, polycarbonate, polyarylate, polystyrene, polyethylene terephthalate, or styrene-based polymers, or various olefin-based resins.

[0030] The primer layer 2 is provided for purposes such as improving adhesion between the resin substrate 1 and the silicone resin layer 3, and improving impact resistance. In the present invention, it also has the effect of eliminating scratches on the surface of the resin substrate 1. Such a primer layer 2 can be formed by applying and curing various resins such as polyester resin, acrylic resin, polyurethane resin, epoxy resin, melamine resin, polyolefin resin, and urethane acrylate resin using a dip coating method.

[0031] Specifically, the silicone resin layer 3 can be formed by applying a siloxane resin, obtained by hydrolyzing a siloxane sol obtained via a condensation reaction based on an alkoxysilane, using a dip coating method and then curing it. Alternatively, other polymers containing siloxane bonds may be used as the silicone resin layer 3. Examples of other polymers containing siloxane bonds include acrylic polymers containing siloxane bonds. However, if an acrylic polymer containing siloxane bonds is used, the primer layer 2 is not required.

[0032] The mixed polysilazane layer 4 is formed by mixing organopolysilazane and perhydropolysilazane, diluting the mixed polysilazane with a solvent as appropriate to adjust the film thickness and viscosity, and then applying it to the silicone resin layer 3 using methods such as dipping, flow coating, spraying, and spin coating, and curing it to convert it into a silica film. The mixed polysilazane can be cured by leaving it at room temperature for several days (in experiments conducted by the applicant, no significant difference was detected in curing time (10 minutes to 3 days) or curing temperature (room temperature to 120°C).

[0033] Vacuum ultraviolet light with a wavelength of 200 nm or less, such as a xenon excimer lamp (vacuum ultraviolet light, wavelength 172 nm), is irradiated onto the mixed polysilazane layer 4. The vacuum ultraviolet light penetrates the mixed polysilazane layer 4 and modifies the silicone resin layer 3 at the interface between the mixed polysilazane layer 4 and the silicone resin layer 3 into a film mainly composed of silicon dioxide. The modified film mainly composed of silicon dioxide is composed of the thickness of the silicon dioxide film from the mixed polysilazane layer 4 and the thickness of the silicon dioxide film modified from the silicone resin layer 3.

[0034] (Experimental Example 1) DURAZANE 1033 was used as the organopolysilazane, and Tresmile #100-15 from Sanwa Chemical Co., Ltd. was used as the perhydropolysilazane.

[0035] Organopolysilazane and perhydropolysilazane were mixed to create seven samples with different organic / inorganic solid content ratios (O / P weight ratio: O / P ratio): 1 wt% (organic g / inorganic g = 1 g / 100 g), 5 wt% (organic g / inorganic g = 5 g / 100 g), 10 wt% (organic g / inorganic g = 10 g / 100 g), 25 wt% (organic g / inorganic g = 25 g / 100 g), 50 wt% (organic g / inorganic g = 50 g / 100 g), 75 wt% (organic g / inorganic g = 75 g / 100 g), and 90 wt% (organic g / inorganic g = 90 g / 100 g). Note that Tresmile #100-15 is sold diluted to 5 wt% with a solvent, so the O / P ratio is the ratio of solids excluding the solvent, not the ratio including the solvent.

[0036] Furthermore, these are diluted with dibutyl ether to a concentration of 5%. A silicone resin layer 3, as shown in Figure 2, is prepared, and the surface of the silicone resin layer 3 is spin-coated at 3000 rpm for 1 minute and cured to form a mixed polysilazane layer 4 with a thickness of 100 nm.

[0037] (Comparative Example 1) The silicone resin layer 3 is directly exposed to vacuum ultraviolet light at 2 J / cm². 2 The silicone resin layer 3 was modified from the top to a film mainly composed of silicon dioxide by irradiation.

[0038] (Comparative Example 2) A perhydropolysilazane, Tresmile #100-15, is applied to the silicone resin layer 3, and vacuum ultraviolet light is applied at 2 J / cm². 2 The silicone resin layer 3 was modified from the top to a film mainly composed of silicon dioxide by irradiation. As mentioned earlier, Tresmile #100-15 is a drug that is originally diluted to 5 wt% with a solvent. This Comparative Example 2 is a sample prepared according to the technique described in Patent Document 4.

[0039] The above samples were subjected to accelerated weathering tests (SUV weathering) using a metal halide lamp, and the time until cracks or delamination occurred was measured. In the SUV weathering tests, irradiation, darkness, and water spray were combined and checked every 120 hours for the occurrence of cracks or delamination (data in 120-hour increments is shown in the figure). The target for SUV weathering was 1200 hours and for heat resistance testing was 1000 hours.

[0040] The results of the SUV weather resistance and heat resistance tests are shown in Figure 3. In Figure 3A, regarding the target weather resistance time of 1200 hours for SUVs, Comparative Example 1 did not reach the target time, but Comparative Example 2 did.

[0041] When the O / P ratio was between 1 wt% and 25 wt%, the target time could be reached. On the other hand, when the O / P ratio exceeded 25 wt%, the effect tended to decrease to the same extent as in Comparative Example 2 (perhydropolysilazane only, 0 wt%). As a result, the desirable range for the O / P ratio in terms of SUV weather resistance is between 1 wt% and 25 wt%.

[0042] Figure 4 shows the abrasion resistance test results when the O / P ratio is changed. In the figure, the "hard coat layer" is an example where the mixed polysilazane was not applied. Of these, the examples from the second "hard coat layer" onwards have undergone modification treatment by vacuum ultraviolet irradiation. Comparative Example 2 is the second "hard coat layer".

[0043] Vacuum UV irradiation yielded a ΔHAZE of ≤2%, indicating that the O / P ratio does not depend on the results of the Taber wear test.

[0044] (Experimental Example 2) A catalyst may be used to cure the mixed polysilazane applied to the silicone resin layer 3. The effect of a catalyst on SUV weather resistance was investigated when a mixed polysilazane containing a catalyst was used. Figure 5 shows the results for a typical metal-based catalyst: palladium acetate, and an amine-based catalyst: 4,4-trimethylenebis-(1-methylpiperidine). The mixed polysilazane used had an O / P ratio of 5 wt% (organic g / inorganic g = 5 g / 100 g), and the experiment was conducted by forming a mixed polysilazane layer 4 with a thickness of 100 nm.

[0045] The results for palladium acetate (Figure 5A) and 4,4-trimethylenebis-(1-methylpiperidine) (Figure 5B) show no difference depending on the type of catalyst, and it was confirmed that catalyst amounts of 0.5% or less do not affect SUV weather resistance. The catalysts expected to be used for curing polysilazanes are as follows.

[0046] Amine-based: Ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, isopropylamine, di-n-propylamine, diisopropylamine, tri-n-propylamine, n-butylamine, isobutylamine, di-n-butylamine, diisobutylamine, tri-n-butylamine, n-pentylamine, di-n-pentylamine, tri-n-pentylamine, dicyclohexylamine, aniline, 2,4-dimethylpyridine, 4,4-trimethyl Nbis-(1-methylpiperidine), 1,4-diazabicyclo[2.2.2]octane, N,N-dimethylpiperazine, cis-2,6-dimethylpiperazine, trans-2,5-dimethylpiperazine, 4,4-methylenebis(cyclohexylamine), stearylylamine, 1,3-di-(4-piperidyl)propane, N,N-dimethylpropanolamine, N,N-dimethylhexanolamine, N,N-dimethyloctanolamine, N,N-diethylethanolamine, 1-piperidineethanol, 4-piperidinol

[0047] Organic acids: Acetic acid, propionic acid, butyric acid, valeric acid, caproic acid

[0048] Metallic: Palladium, palladium acetate, palladium acetylacetonate, palladium propionate, nickel, nickel acetylacetonate, silver, silver acetate, silver acetylacetonate, platinum, platinum acetylacetonate, ruthenium, ruthenium acetylacetonate, ruthenium carbonyl, gold, copper, copper acetylacetonate, aluminum acetylacetonate, aluminum tris(ethylacetoacetate)

[0049] (Experimental Example 3) The effects of increasing the amount of vacuum ultraviolet irradiation were investigated. The mixed polysilazane used had an O / P ratio of 5 wt% (organic g / inorganic g = 5 g / 100 g), and the experiment was conducted by forming a mixed polysilazane layer 4 with a thickness of 100 nm.

[0050] The Taber test was performed according to ASTM D1044. Furthermore, the conditions for the wiper test are as follows: A 400nm long wiper was used to drop sand (JIS test powder type 1 (silica sand, particle size 45-300μm)) at a constant flow rate of 5mm / min (7.3g / min) into the center of the wiping area. 990 back-and-forth passes were performed (test time: 30min x 33 back-and-forth passes / min).

[0051] Figure 6 shows the results. Vacuum ultraviolet irradiation dose was 10 J / cm². 2 At these levels, cracks or delamination occurred in SUV weather resistance and heat resistance tests. Therefore, the vacuum ultraviolet irradiation dose should be 2 to 10 J / cm². 2 Less than is preferable.

[0052] Furthermore, in Patent Document 4, when the film thickness is 88 nm using perhydropolysilazane alone, the irradiation dose of vacuum ultraviolet is 2.9 J / cm². 2When the above value was exceeded, a tendency for the Taber test results to deteriorate was observed. However, in the present Experimental Example 2, in the case of the polysilazane layer 4 having a film thickness of 100 nm, as the irradiation amount of vacuum ultraviolet light increases, the Taber test result becomes favorable. When the irradiation amount of vacuum ultraviolet light is 10 J / cm 2 , ΔHAZE ≤ 1% was achieved for the items of the Taber test and the wiper test. This is the opposite result to the case of Patent Document 4. Therefore, in applications specialized for resistance in the Taber test, the irradiation amount of vacuum ultraviolet light can be used even when it is 10 J / cm 2 or more.

[0053] (Experimental Example 4) In the above experiments, the film thickness of the mixed polysilazane layer 4 was set to 100 nm, but a heat resistance test, an SUV weather resistance test, and a Taber abrasion test were also performed for other film thicknesses. The results are shown in Figure 7. The content is 5 wt% (organic g / inorganic g = 5 g / 100 g), and the irradiation amount of vacuum ultraviolet light is 2 J / cm 2 .

[0054] Regarding the heat resistance test, when the film thickness of the mixed polysilazane layer 4 reached 565 nm, the target 1000 hours was not reached. Further, regarding SUV weather resistance, when the film thickness of the mixed polysilazane layer 4 reached 772 nm, the target 1200 hours was not reached. Therefore, to satisfy the targets for heat resistance and SUV weather resistance, the film thickness is desirably less than 565 nm. On the other hand, even when the film thickness of the mixed polysilazane layer 4 was 11 nm, the target 1200 hours for SUV weather resistance was achieved. Therefore, the film thickness of the mixed polysilazane layer 4 is preferably 11 nm or more and less than 565 nm.

[0055] In this embodiment, it was found that mixing organopolysilazane with perhydropolysilazane makes application to the silicone resin layer 3 easier than when organopolysilazane is used alone. Next, the film thickness of the mixed polysilazane layer 4 was examined when vacuum ultraviolet light with a wavelength of 200 nm or less was irradiated from above the applied and cured mixed polysilazane layer 4, and it was found that if the film thickness is less than 565 nm, a transparent laminate with excellent SUV weather resistance can be obtained. In Patent Document 4, 100 nm was considered the limit for increasing the film thickness when using perhydropolysilazane alone, but by mixing 5 g of organopolysilazane with 100 g of perhydropolysilazane (5 wt%), the film thickness could be dramatically increased. Since the range of film thickness of the mixed polysilazane layer can be widened, it is possible to increase productivity and control the quality of the film thickness for large areas and curved surfaces of windshields for vehicles such as automobiles and railways, airplanes and ships, etc.

[0056] Furthermore, according to this embodiment, the O / P ratio of organopolysilazane and perhydropolysilazane was investigated, and it was found that if the mixed polysilazane layer 4 has an O / P ratio of 1 wt% to 25 wt%, a transparent laminate with excellent SUV weather resistance can be obtained.

[0057] In this embodiment, as vacuum ultraviolet light with a wavelength of 200 nm or less, light obtained from an excimer laser or excimer lamp with wavelengths of 157 nm (F2 laser), 172 nm (Xe2), or 193 nm (ArF) can be used. By making the penetration depth of the vacuum ultraviolet light into the silicone resin layer 3 longer than the thickness of the mixed polysilazane layer 4, a silicon dioxide film with a larger proportion on the silicone resin layer 3 side can be formed. [Explanation of Symbols]

[0058] 1. Resin substrate 2. Primer layer 3. Silicone resin layer 4. Mixed polysilazane layer 10 Transparent Laminate

Claims

[Claim 1] A transparent laminate for a windshield, wherein a silicone resin layer made of an alkoxysilane-based siloxane resin is formed on a resin substrate, A mixed polysilazane, in which organopolysilazane is mixed with perhydropolysilazane in a solid content ratio (O / P ratio) of 1 wt% to 25 wt%, is applied to the surface of the silicone resin layer and cured to form a mixed polysilazane layer with a film thickness of 11 nm to less than 565 nm. A method for manufacturing a transparent laminate, characterized in that a portion of the silicone resin layer is modified into a modified silicon dioxide film through the mixed polysilazane layer by irradiating the mixed polysilazane layer with vacuum ultraviolet light of a wavelength of 200 nm or less at an irradiation dose of 2 J / cm² to 8 J / cm², and the modified silicon dioxide film is composed of a silicon dioxide film made from the mixed polysilazane layer and a silicon dioxide film modified from the silicone resin layer.

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