JPS6118901A - Low reflection working agent - Google Patents

Abstract

PURPOSE:To improve the durability by forming the low reflection working agent of a bis-silane compound containing a polyfluoroalkylene group shown by a formula or condensate, or a cocondensate of the compound shown by the formula and another silane compound. CONSTITUTION:The low reflection working agent is formed of the bis-silane compound containing the polyfluoroalkylene group shown by the formula [X is Cl, OR<1>, R<1>COO (R<1>: lower alkyl group) and Rf is a polyfluoroalkylene group having at least one CnF2n+1 (m: integer between 1-6) branch and may contain -(CH2)m- (m: integer between 1-3), -O-, -S-, etc.] or condensate, or condensate shown by the formula and another silane cocondensate. This working agent when used is diluted with an organic solvent of acetone, alcohol, etc.

Description

[Detailed description of the invention]

The present invention relates to a low-reflection finishing agent useful for reducing the surface reflection of a transparent substrate such as glass or transparent plastic by treating the surface of the substrate. Windows, doors, and shop windows of buildings and vehicles. For showcases, optical lenses, eyeglass lenses, sunglasses, etc., it is essential to use transparent materials such as glass or transparent plastic. However, the surface of such transparent materials is prone to glare and dazzle due to reflection of sunlight and illumination light.
Another drawback is that the transparency and see-through characteristic of the material are impaired due to the reflection of the surrounding scenery. In addition, when using sunlight, for example, in solar water heaters, in order to improve the heat collection efficiency, it is necessary to eliminate reflection loss of the transparent material used for the heat collection part, reduce the reflection loss, and allow a large amount of energy to pass through. It is. Conventionally, antireflection on the surface of transparent substrates such as glass and transparent plastics has been developed mainly for optical components. For example, to prevent reflection of visible light on the glass surface, M
gF2. Single-layer films made of quartzite, etc., and single-layer films made of Sin, 0e02°ZnS, etc. for infrared use, Si
A multilayer film consisting of O-MgF, argon trisulfide-WO2-cryolite, etc. is used, and for ultraviolet use, 5to2.
A single-layer film made of LiIP or the like is formed as an antireflection film by a vacuum evaporation method or a sputtering method, and is put into practical use in optical lenses, eyeglass lenses, filters, and the like. Recently, these methods of forming antireflection films have also been applied to heat-reflecting glass sheets. On the other hand, on the surface of a transparent substrate such as glass or transparent plastic, a low-reflection treatment agent made of a polymeric substance is completely coated, sprayed,
Alternatively, a low-reflection treatment agent or treatment method has been proposed for forming a low-reflection coating film by immersing it in a treatment agent. From this perspective, adaptive articles are limited to relatively small precision optical components and are not suitable for continuous production. When a coating film of a low-reflection treatment agent is formed by coating, spraying, or dipping, the adhesive strength between the transparent substrate and the low-reflection treatment agent is weak, and the durability of the formed low-reflection coating film may be affected. For example, the formed low-reflection coating film is easily contaminated, is damaged by cleaning operations to prevent contamination, and has shortcomings in hardness and durability, such as being easily peeled off. Based on the recognition of the above-mentioned problems, the inventors of the present invention have devised a technique for coating, spraying, or deep dipping on the surface of a transparent substrate such as glass or transparent plastic without impairing its transparency or see-through. Various studies have been carried out in order to provide a highly durable low-reflection finishing agent that can make the surface of the substrate low-reflectivity by the known method and maintain its performance over a long period of time.
We have considered this. Conventionally, polyfluoro group-containing compounds have a low polarizability of fluorine atoms and a low refractive index, for example, osF+s.
The refractive index of
'9)s N ke 1.290, (OF!=OF, 10
The polymer of 1r3001F==OF't) is 1.
330, and it is known that low reflectivity can be imparted by forming a coating film of such a compound on the entire surface of a transparent substrate such as glass or transparent plastic. 5. Among polyfluoro group-containing compounds, polyfluoro group-containing silane compounds have excellent adhesion to transparent substrates, for example, Rf02H4x3 (where, Rf is a polyfluoroalkyl group, and X is 01゜Alkoxy group)V
i) It is useful as a component of a low-reflection finishing agent that has low reflectivity and adhesive properties. However, since the coating film hardness of the low-reflection treatment agent formed on the surface of the transparent substrate is low, the coating film hardness? Enhanced low-reflection finishing agents are disclosed in Japanese Patent Application Laid-open Nos. 58-167448 and 1983 by the same applicant as the present invention.
It is disclosed in Japanese Patent Application Laid-Open No. 59-26944. On the other hand, as a cylindrical polyfluoro group-containing silane compound with high coating film hardness, for example, X@8101H4
0ny! The polyfluoroalkylene group-containing bissilane compound No. H481X3 (or the same as above, n is an integer of 1 to 20) is attracting attention. However, the refractive index is high compared to the fluorine content, and even if the surface of a transparent substrate is treated with a single compound as a low-reflection agent, the low-reflectivity is poor, and it is not suitable as a component of a low-reflection agent. Therefore, the present inventor developed a polyfluoroalkylene group-containing bissilane compound as a component of a low-reflection finishing agent that has low reflectivity and can form a low-reflection coating film with high adhesion to transparent substrates and high hardness. We investigated its suitability as a low-reflection finishing agent. As a result, in polyfluoroalkylene group-containing bissilane compounds, by specifically branching the fluoroalkyl chain in the structure, the low surface energy property of the fluoroalkyl chain is improved, and therefore a coating film with a low refractive index and high hardness can be formed. The present invention was completed based on the knowledge that it can be used as a low-reflection processing agent. The present invention provides a low-reflection treatment agent for treating the surface of a transparent substrate, which has the following general formula xs 83. Rf -slxm II (X is 01. OR'I OOR', n, Jd
A polyfluoroalkylene group having at least one anF'tn++ branch in its composition. -o-, -s-, etc. may be contained, R1#i is a lower alkyl group, m is an integer of 1 to 6, and n is an integer of 1 to 3 t-. ) The present invention provides a low-reflection finishing agent characterized by being composed of a polyfluoroalkylene group-containing bissilane compound or a combination thereof, or a co-condensate of the compound and another silane compound. In the present invention, the polyfluoroalkylene group-containing bissilane compound represented by the general formula x3si-Rf-8iXs (where X and Rf are the same as above) has at least one On'? Typical examples of such compounds are polyfluoroalkylene group-containing trichlorobissilane compounds such as OFS 0F3 0, F, 02 F, which have a QQ+1 fluoroalkyl group as a branch. Examples include polyfluoroalkylene group-containing trimethoxysilane compounds such as and polyfluoroalkylene group-containing triethoxybissilane compounds such as . In the present invention, the polyfluoroalkylene group-containing bissilane compound may be a co-condensate with another silane compound for the purpose of improving adhesiveness. Silane compounds suitable for such co-condensation are preferably those that do not increase the refractive index, and examples thereof include 0H381(00)Is)s, C)-81, (OO
H3)3, (OH,0)3SiO6H,,5i(O
OH3)3゜H81013, 0H3EIi013 and other trimethoxysilane or trichlorosilane compounds, or "("Hm)4 + 81(
Tetraalkoxysilanes and tetrachlorosilanes represented by OO1H6)4*EIiO14 and the like can be used. The blending ratio of the co-condensate is appropriately selected depending on the relationship between the refractive index and adhesiveness of the coating film formed as the low-reflection finishing agent. Said 2 tons of polyfluoroalkylene group-containing alcohol? The process is carried out in the presence of acetic acid as a catalyst in solution A, and a 1% aqueous solution of acetic acid is used. The low-reflection finishing agent of the present invention is used in a diluted form with an organic solvent such as acetone or alcohol. The processing method for transparent substrates is particularly limited.
It is applied by conventional brushing, rolling, spraying and dipping methods. The thickness of the coating film is 1 μm or less, preferably 0.2 μm to 0.05 μm, and if it is 1 μm or more, the low reflection effect tends to decrease. This film thickness is determined, for example, by the dilution conditions with an organic solvent and the pulling-up speed after dipping during coating. 100℃~20℃ after application
30 minutes at a temperature of 0°C, preferably 120°C to 150°C
Hold for 180 minutes, preferably 45 to 120 minutes to cure. The low-reflection finishing agent of the present invention has adhesive properties that can withstand practical use when directly applied to transparent substrates such as glass or transparent plastics, but depending on the type of transparent substrate, the adhesive properties may be poor or even stronger. In order to
It is also possible to treat a coating film previously formed on a transparent substrate with a primer. Such primers include, for example, OH3 0H2=0000(OH2)3Si(OOH3)3.
H8(OH2)3EIi(OOH3)3゜N00(O
Hz) 3 days 1. (002H5)3, O'1(
OH2)3Eli(OOI(3'13 +0H2=O
H()OH2NH(01(2), NH(OH2)3Si
(OOH,)3゜0te) ”hOH2Sj (OCHs
) a + CH35i (OOH3)s. A condensate of silane coupling agents or a co-condensate of two or more of them are used. The refractive index of the condensate or co-condensate of such a silane coupling agent is 1.47 to 1.60, which is comparable to or slightly higher than that of glass or transparent plastic. Brimer also contains inorganic oxides,
It may also contain an organic resin. Primer is an organic solvent, for example acetone. Dissolved in tetrahydrofuran, lower alcohol, etc.,
A solution of ~50 tbsp, preferably 15 to 40 tbsp, is applied onto a transparent substrate and dried for 10 minutes to 1 hour at room temperature or, if necessary, at a temperature of about 100°C, to ensure that crosslinking is partially removed. It is preferable to apply the low-reflection finishing agent of the present invention when the surface is in an advanced state. Brimer film thickness is at least 0
．． 1μ, preferably 0.5μ to 3μ, and the higher the At, the harder the coating film of the low-reflection agent formed on the upper layer will be. It is not preferable to make it thicker than necessary. The visible light reflectance of the transparent substrate treated with the low-reflection finishing agent of the present invention and on which a coating film is formed is 0.8 to 1.5.
The reflectance of ordinary soda lime glass is 4.2%,
Excellent effects are recognized since the reflectance of methacrylic resin is 3.9% and the reflectance of polycarbonate is 4.8%. Furthermore, the hardness of the formed coating film is a pencil hardness of H to 5H, and the effect is also recognized because the pencil hardness of the coating film made of a condensate of a polyfluoroalkyl group-containing silane compound is B. The low-reflection finishing agent of the present invention is suitably used not only for glass but also for transparent plastics such as polyvinyl chloride, polymethyl methacrylate, polycarbonate, polydiethylene glycol bisallyl carbonate, polystyrene, unsaturated polyester, etc., and the applications of treated articles are particularly limited. Building windows, doors, show windows,
Showcases, vehicle windows/windshields, optical lenses, eyeglass lenses, safety glasses, filters. It can be used for television display front anti-glare 1 watch glasses, sunlight condensing members, and other glass or transparent plastic products. EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples. In addition, in the examples, the evaluation method of the coating film formed with the low-reflection finishing agent is as follows. Reflectance measurement: Using a self-recording spectrophotometric needle specular reflection light metering accessory device (newly manufactured by Hitachi: Model 323) at a wavelength of 400 $7~7
Measure the average reflectance at an incident angle of 5° at 00nμ. Film thickness measurement = 1 Tayl step' (Rank Tail
It is determined by measuring the stylus force using a stylus (manufactured by Or Hobson). Pencil hardness: lead edge scratch tester (, R-tech s-x 5401
)use. Synthesis example】 0H2-CIHO1120(OH2)ssi(00zH
s) s 139F+ 0.1N −ゝ. ' HO127F was placed in a four-bottle flask with an internal volume of 500 txl equipped with a stirrer, and after reacting at room temperature for 48 hours,
A primer was prepared consisting of 150 t of a 30% methanol solution of silica sol, 51 f of methanol, and a condensate of a silane coupling agent with a viscosity of a and 5 op. Synthesis example 2 0H, -0HOH, 0(OH)ssi(OO2Hs)
s 83.4 t.ゞ. ' H2N(OH2)2 NH(OH2)3 Si(OOH
3) m 66.6 is the temperature needle. Equipped with a stirrer and a cooling tube, the mixture was placed in a four-bottle flask with an internal volume of 500 d, and reacted at 80°C for 2 hours, then cooled to room temperature, added with isopropyl alcohol 17 Off, and mixed with a silane coupling agent with a viscosity of 17 cp. A primer consisting of a condensate was prepared. Example 1 The following formula [A] (OH30)ms102H40F(07=)sOF02 as a polyfluoroalkylene group-containing bissilane compound
H4Si(00Ha)3[AlI3 0F3C! F3 total 2.9 parts (parts by weight, same below), t-butanol 96
．． 7 parts and 64 parts of a 1% aqueous acetic acid solution were reacted by stirring at room temperature for 12 hours, and then filtered to prepare a low-reflection finishing agent. Separately, glass plates (soda-lime glass) and polydiethylene glycol bisallyl carbonate (hereinafter referred to as carbonate plates) were washed with detergent, washed with water, and then dried.
, all of which are 5 tm x 5 tm square, were immersed in the above-mentioned low-reflection processing agent solution prepared in advance, and 6 cm
After pulling up at a speed of 1 minute, heat treatment was performed at a temperature of 120° C. for 1 hour to form a coating film. The thickness of each coating film formed was 0.1 μm. The pencil hardness and reflectance of the coating film were as follows: Pencil hardness Reflectance (correspondence) Glass plate ■1.2 Garponate plate ■1.0. Example 2 A glass plate and a carbonate plate similar to those in Example 1 were immersed in the primer prepared in Synthesis Example 1 and dried at 9c≠ to form a primer coating. A coating film was formed by processing the processing agent. The thickness of the entire coating film formed was 21 μm for both the glass plate and the carbonate plate. The measurement results of physical property values are shown in Table 1. Example 3 The same glass plate and carbonate plate as in Example 1 were immersed in the primer prepared in Synthesis Example 2, pulled up at a speed of 9 m/min, and dried at room temperature for 1 hour to form a primer coating. Thereafter, it was treated with the same low reflection agent as in Example 1 to form a coating film. The thickness of the coating film formed on the glass plate and the carbonate plate was 2.1 μm. The measurement results of physical property values are shown in Table 1. Table 1 Examples 4 to 5 In the low reflection finishing agent of Example 1, the polyfluoroalkylene group-containing bissilane compound was expressed by the following formula [B] and

It was prepared in the same manner as in Example 1 except that [0] was replaced. Separately, a glass plate and a carbonate plate on which a primer coating was formed were prepared in the same manner as in Example 2, immersed in the above-mentioned pre-prepared low-reflection finishing agent solution, and pulled up at a speed of 15 m/min. Thereafter, heat treatment was performed at a temperature of 120° C. for 1 hour to form a coating film. The total thickness of the coating film formed on the glass plate and the carbonate plate was 21 μm. The measurement results of physical property values are shown in Table 2. Table 2 Examples 6 to 8 In the low reflection finishing agent of Example 1, the polyfluoroalkylene group-containing bissilane compound is represented by the above formula (A), and the third
A low reflection finishing agent was prepared by co-condensing with other silane compounds shown in the table in the same manner as in Example 1. Separately, a glass plate and a carbonate plate on which a primer coating had been formed were prepared in the same manner as in Example 2, immersed in the above pre-prepared low-reflection finishing agent solution, and pulled up at a rate of 15 g/min. Thereafter, heat treatment was performed at a temperature of 120° C. for 1 hour to form a coating film. The total thickness of the coating film formed on the glass plate and the carbonate plate was 2.1 μm. The measurement results of physical property values are shown in Part 3. Comparative Examples 1 to 3 Comparative examples 1 to 3 were prepared in the same manner as in Example 1, except that the polyfluoroalkylene group-containing bissilane compound in the low-reflection finishing agent of Example 1 was replaced with the polyfluoroalkylene group-containing silane compound shown in Table 4. Next, a glass plate and a carbonate plate were immersed in the prepared liquid in the same manner as in Example 1, and treated in the same manner as in Example 1 to form a coating film. The thickness of the formed coating film is 0 in all cases.
．． It was 1μ. The physical property values of the coating film were shown to the fourth group, and when the coating film is hard, the reflectance is high, and on the other hand, when the reflectance is low, the coating film is weak, and as in Examples 1 to 8, both physical property values were satisfied. Not yet. The hardness of the carbonate plate in Comparative Example 3 is 0, which indicates the surface hardness of the carbonate plate.

Claims (1)

[Claims] A low-reflection finishing agent for treating the surface of a transparent substrate has the following general formula: at least one CnF_2n_+
A polyfluoroalkylene group having a branch in its structure, which may contain -(CH_2)-_m, -O-, -S-, etc., R^1 is a lower alkyl group, and m is an integer from 1 to 6. , n represents an integer from 1 to 3. ) A low-reflection finishing agent comprising a polyfluoroalkylene group-containing bissilane compound or condensate, or a co-condensate of the compound and another silane compound.