JPH03265547A - Surface treatment of glass - Google Patents

Abstract

PURPOSE:To improve the defective wettability of the bottom of glass and ununiformity in the adhesion of coating on the top of the glass by bringing an acidic aq. soln. of a specified pH contg. phosphate ions into contact with the clean glass, washing and drying the glass. CONSTITUTION:An acidic aq. soln. of pH <=5.0 contg. >=0.1g/l phosphate (PO4) ions is brought into contact with clean glass and this glass is washed and dried. In the case of <0.1g/l phosphate ion content, the pH of the soln. rises and the wettability improving effect of phosphate ions on the surface of glass is reduced. Since high phosphate ion concn. causes the corrosion of an apparatus and the reduction of work efficiency, the desirable concn. is usually 1-10g/l. The wettability of the surface of glass can further be improved by bringing an aq. phosphoric acid soln. contg. fluorine ions and/or fluorine complex ions by >=0.1g/l (expressed in terms of F) into contact with the glass.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention applies to the surface of glass, especially float glass, with excellent adhesion, such as silicate coatings (Silvie Coat (Yotoral Kagaku), CRM Coat Okuno Pharmaceutical Co., Ltd.), Ceramic Power (Nichiban Research Institute Co., Ltd.), This invention relates to a novel glass surface treatment method as a pretreatment for inorganic coating such as )) or metal coating by various metal plating. [Prior Art] In order to obtain high smoothness, recent plate glasses are manufactured by a method in which molten glass is floated on molten metal tin, that is, a float method. Glass produced by this method is called float glass. The surface of the glass plate manufactured by this method has tin diffused into the glass due to contact with molten tin, so the glass surface (bottom surface) that came into contact with tin has poor wettability and is coated directly with inorganic coating. Since there is a problem in that the adhesion of the coating film is very poor when applying molten tin, conventional methods are to analyze whether it is the bottom surface or the glass surface (top surface) that does not come in contact with molten tin, and then coat the top surface with an alkaline coating. After cleaning the surface with a cleaning agent, coating was performed. [Problems to be Solved by the Invention] However, even on the top surface, the adhesion of the coating film varies considerably and may be poor. A follow-up study of the variable factors revealed that the factors include the number of days that have passed from the date of manufacture of the glass to the time of coating, and the storage period when the manufactured glass is stored with a mount in between. In the industry, the poor wettability induced on the glass surface due to storage with a backing paper in between is called interleaving fading. Therefore, the inventors of the present invention conducted extensive studies with the aim of improving poor wettability and variations in the adhesion of the top surface coating, which are factors that reduce the adhesion of the inorganic coating on the bottom surface of float glass. [Means for solving the problem] As a result, by bringing the surface of the float glass, which has a clean surface, into contact with an aqueous solution containing phosphoric acid at a specific concentration, the wettability of the bottom surface can be greatly improved, and the inorganic coating on the top surface can be adhered. We discovered that it is possible to eliminate gender disparities. As a result of further studies, the present inventors found that the inorganic coating film greatly contributes to improving the adhesion not only to float glass but also to other glass materials and various optical lenses.
Furthermore, they have discovered that it provides excellent coating adhesion as a pretreatment for various metal coatings. That is, the present invention uses phosphate (PO4) ions at 0.1 g/l.
The present invention relates to a method for surface treatment of glass, which comprises contacting a surface-clean glass with an acidic aqueous solution having a pH of 5.0 or less containing the above, followed by washing with water and drying. The composition and treatment method of the treatment liquid of the present invention will be explained below. The phosphoric acid content of the acidic aqueous solution used in the present invention is 0.1 g/i as phosphoric acid (PO4) ion! , or more is required. When O is less than 1 g/ρ, the pH becomes high and the effect of improving the wettability of the glass surface by phosphoric acid is weakened. If the phosphoric acid concentration is high, there is no problem in applying the treatment method of the present invention, but equipment corrosion and workability become problems, so 1 to Log/ρ is usually desirable. Phosphoric acid (PO,) ions It can be supplied to the treatment solution of the present invention in the form of sodium and potassium phosphate salts. As a result of further studies, the present inventor discovered that by contacting a phosphoric acid aqueous solution containing 0.1 g/l or more of F, which is one or more types of ions selected from fluorine ions and fluorine complex ions, to the glass surface. It has been found that the wettability of the surface is further improved. In this case, the content is F
The ideal value is 0.1g/12 or more, and usually 0.1g/12 or more.
．． 1 to 10 g/l is desirable. Next, the pH of the acidic aqueous solution needs to be 5.0 or less;
．． When it exceeds 0, the effect of improving the wettability of the glass surface becomes weak. Further, the method of bringing the phosphoric acid aqueous solution into contact with the glass surface is not particularly limited, but may be any conventionally known method such as spraying or dipping. The contact time is related to temperature and time, and the contact time can be shortened by increasing the temperature. However, since the object to be coated is glass, it is not preferable to subject it to sudden temperature changes. In consideration of workability, the contact temperature is preferably 40 to 70°C and the contact time is preferably 5 to 20 minutes. Processing steps usually include, for example, alkaline cleaning →
Washing with water - treatment with the acidic aqueous solution of the present invention - washing with water → drying → coating is performed in this order, but the washing with water and drying steps after the acid treatment in the treatment with the acidic aqueous solution of the present invention are important.
During the initial washing, it is necessary to thoroughly wash with fresh water to remove excess acid, and then dry thoroughly to evaporate the water. Preferably, the initial drying is performed at room temperature so as not to distort the glass. However, the acidic aqueous solution used in the present invention does not only contain the above-mentioned components, but may also contain a cellosolve system such as butyl cellosolve as a water-soluble organic solvent and/or a surfactant to lower the surface tension. By adding an agent or the like, it is possible to impart cleaning properties for organic substances, and thus it becomes possible to carry out acid treatment and cleaning in the same process. [Effect] It is not clear why the adhesion of an inorganic coating or a metal coating to the bottom surface of a float glass is improved by pre-treating that surface with an acidic aqueous solution of phosphoric acid, but the following is true. It is inferred. In other words, for the bottom surface, phosphoric acid efficiently removes the tin oxide present on the surface; in this case, a small amount of F is added to the phosphoric acid aqueous solution.
Addition of ions promotes the removal action of tin oxide;
Phosphoric acid effectively removes trace amounts of carbonate present on the glass surface that are harmful to coating adhesion; furthermore, phosphoric acid adsorbed on the glass surface contributes to improving coating adhesion. [Example] The present invention will be described in detail below with reference to Examples. 0 substrate: float glass plate (75x50xO, 3/mm
) 0 coating: Alkaline silicate-based inorganic paint Nippon Bariki Rising Co., Ltd. Pulcera Coat-700S (white) Spray coating, baking: 230°C x 20 minutes, film thickness: 20 μm Example 1 Treatment process Alkaline cleaning - water washing → Acidic aqueous solution (processing according to the present invention) - water washing → air blow → drying at room temperature - Coating 1, alkaline cleaning process FC-4360 (manufactured by Nippon Parkerizing Co., Ltd.: strong alkaline cleaner) 10 g/il Immersion temperature 60°C Immersion time 5 minutes 2 , acidic aqueous solution treatment component Phosphoric acid 0.2g/ρ (as PO4) pH 3.2 Immersion temperature 60°C Immersion time 20 minutes Example 2 Treatment process Alkaline cleaning - water washing → acidic aqueous solution (processing according to the present invention) - water washing → air blow → Room temperature drying - Coating 1, Alkaline cleaning process FC-4360 (manufactured by Nippon Vercalizing Co., Ltd.: strong alkaline cleaner) 10 g/l Immersion temperature 60°C Immersing time 5 minutes 2, Acidic aqueous solution treatment component Phosphoric acid 100 g/l (as PO4 ) pH 0,8 Immersion temperature 40°C Immersion time 20 minutes Example 3 Treatment process Alkaline cleaning → Water washing → Free aqueous solution (processing according to the present invention) → Water washing → Air blow → Room temperature drying → Coating 1, Alkaline cleaning process FC-4360 (Japan) Manufactured by Bariki Rising Co., Ltd.: Strong alkaline cleaner) Log/l Immersion temperature 60℃ Immersion time 5 minutes 2, Acidic aqueous solution treatment components Phosphoric acid 10g/ρ (as PO4) Sulfuric acid 10g/ρ (as SO2) pH 1.0 Immersion Temperature: 40°C Immersion time: 20 minutes Example 4 Treatment process Alkaline cleaning → Water washing – Acidic aqueous solution (treatment according to the present invention) – 4 Water washing → Near blow – Room temperature drying → Coating 1, Alkaline cleaning process FC-4360 (Nihon Buriki Rising Co., Ltd.) ) Manufactured by: strong alkaline cleaner) 10 g/l Immersion temperature 60°C Immersion time 5 minutes2, acidic aqueous solution treatment components Phosphoric acid 10 g/42 (as PO4) Hydrofluoric acid 0.5 g/Q (as F) pH 1.5 Immersion Temperature: 40°C Immersion time: 20 minutes Example 5 Treatment process Alkaline cleaning → Water washing - Acidic aqueous solution (treatment according to the present invention) - Water washing → Air blow → Room temperature drying - Coating 1, Alkaline cleaning process FC-4360 (Nippon Pariki Rising Co., Ltd.) Made by strong alkaline cleaner) 10g/l Immersion temperature 60℃ Immersion time 5 minutes2, Acidic aqueous solution treatment ingredients Phosphoric acid 10g/ρ (as PO4) Silicic acid 0.5g/flood (as F) pH 1.6 Immersion temperature 40 °C Immersion time 20 minutes Comparative example 1 (method outside the scope of the present invention) Treatment process Alkaline cleaning → Water washing - Acidic aqueous solution - Water washing → Near plow - Drying at room temperature → Coating 1, Alkaline cleaning process FC-4360 (Nihon Buriki Rising Co., Ltd.) Manufacturer: strong alkaline cleaner) 10g/ρ Soaking temperature 60°C Soaking time 5 minutes 2, Acidic aqueous solution treatment component Phosphoric acid 0.05g/l2 (as PO4) pH 5,8 Soaking temperature 80°C Soaking time 40 minutes Comparative example 2 (conventional) Method) Treatment process Alkaline cleaning → Water washing → Drying → Coating 1, Alkaline cleaning process FC-4360 (manufactured by Nihon Pariki Rising Co., Ltd.: strong alkaline cleaner) 10 g/l Immersion temperature 60°C Immersion time 5 minutes Evaluation method Usually, coating The adhesion of the film is evaluated by the grain adhesion test, Erichsen test, DuPont impact test, etc. However, since the object to be coated in the present invention is glass, the Erichsen test and DuPont impact test, in which the object to be coated is deformed, are not suitable. Can not. Furthermore, this inorganic coating film had a smaller adhesion to Scotch tape than a normal organic coating film, and the difference in adhesion was difficult to show in the cross-cut adhesion test, so it could not be evaluated. Therefore, we conducted an adhesion test using duct tape and further tested the back side of the glass (
Visual evaluation was performed from the non-coated side). This visual evaluation takes advantage of the transparent property of glass, allowing the contact surface between the coating film and the glass surface to be observed. This visual evaluation has the advantage of allowing a more detailed judgment of adhesion that does not occur when peeling off the tape. Judgment Criteria 1, Gum tape peeling test 0: No abnormality O: 1-10% peeling △: 1 1-50% peeling ×: 50% or more peeling 2° Visual observation 0: No abnormality ○: 1-10% abnormality △: 1- 50% abnormality ×: 50% or more abnormality (margin below)

【Effect of the invention】

The glass pretreatment method of the present invention can improve the adhesion of inorganic coatings or metal coatings not only to float glass but also to various glasses. Furthermore, when coating float glass, the conventional step of detecting the top surface by analysis can be omitted, and the coating can be applied to any surface.

Claims (1)

[Claims] 1. A glass characterized by contacting a surface-clean glass with an acidic aqueous solution containing 0.1 g/l or more of phosphate (PO_4) ions and having a pH of 5.0 or less, followed by washing with water and drying. surface treatment method. 2. The acidic aqueous solution further contains one or more ions selected from fluorine ions and fluorine complex ions as F.
．． The method for surface treatment of glass according to claim 1, wherein the glass surface treatment method contains 1 g/l or more. 3. A method for surface treatment of glass, which comprises applying an inorganic coating or a metal coating to the surface of the glass after the surface treatment according to claim 1 or 2.