【LUCK GLASS]How to prevent glass mold? What are the methods to prevent glass mold?

1.Overview

In the process of preparing the glass product by the traditional melting method, in order to reduce the cost, the soda ash is selected as the flux, and then the glass product is easily weathered under the certain conditions. Moldy glass also known as anti-alkali glass is due to glass storage time is too long or wet weather caused by chemical reaction; in the sunlight under the surface of a rainbow, mold, watermark, ink, paper and so on. Moldy glass is a storage and transportation problems that occur after the glass moldy surface will lose luster, loss of transparency, showing rainbow, white or patch phenomenon and so on. Glassy mildew usually occurs on the air side of the float glass because the lower surface of the float glass comes in contact with the tin liquid and the surface is infiltrated with a thin layer of tin which protects the glass.

2. Glass Mold Can Be Divided Into the Following Stages:

1) Initially, water or moisture is adsorbed on the glass surface.

2) Then, water or moisture diffuses into the glass.

3) The soluble silicate in the surface layer is hydrolyzed and destroyed. First, sodium silicate and potassium silicate, etc. are hydrolyzed and destroyed. Caustic soda (NaOH) is formed and SiO2 is separated.

4) The separated SiO 2 forms a silicone gel and forms a protective film on the glass surface, which prevents further erosion.

5) Hydrolysis caustic soda formed, and the role of carbon dioxide in the air to produce sodium carbonate, gathered in the glass surface, forming the surface of the film soluble salt. Because of its strong hygroscopicity, moisture absorption and deliquescence, the final formation of lye droplets. When the ambient temperature and humidity changes, the concentration of these droplets also changes. If the condensed lye droplets come in contact with the glass over a prolonged period of time, the gel-like silicon oxide film may be partially dissolved therein, causing severe localized erosion of the glass surface to form blobs. This is a migration of sodium ions from the glass body out of white air with the reaction of alkali-rich ion groups. Scanning electron microscopy white particles can be observed.

3.Moldy Identification and Inspection Methods

Visual ppearance Topography is the most concise and feasible method. Both in concentrated glare, the sample is placed in the reflected light and transmitted light to observe the glass surface with spots and fog. These spots and mist can not be rubbed with cloth or water. The appearance of the glass, said the sample has mold. A few moldy and misty molds were observed with the naked eye under concentrated glare. If under concentrated glare, many spots and light mist are observed with the naked eye as medium moldy. Some naked spots and haze are seriously moldy if left unattended. Mildew can also be observed under natural light through the spray moisturizing method.

4.Prevent Glass Moldy

On the one hand with the surface properties of the glass itself, but also with the anti-mildew treatment taken before the float glass packaging, packaging and sealing, storage conditions are closely related. When the float glass forming, annealing, generally taken online packaging, the temperature of the glass is about 50 ~ 100 ℃. Packaged glass subject to inventory, transport to the user, sometimes a long time. If you encounter high temperature, high humidity season, improper storage and transportation, box glass will appear moldy. Moldy appears in the air side of the float glass,because the glass tin surface (under the surface) is because ① ② ③ ④ ⑤ ⑥ ⑦ ⑧ mechanism glass defects, the original packaging mold process P45 at room temperature or slightly above room temperature, the fresh glass surface The adsorption of moisture and grease from the surrounding environment, the adsorption of water OH-based forms combined with Si4 +, affecting the structure of the glass surface.

Since OH- ions can form hydrogen chains and adsorb other substances, the clean glass surface can be rendered hydrophilic by the surface of water, ethanol or sulfuric acid, but only becomes hydrophobic due to the attachment of other substances.

The glass surface has the following characteristics: ① During the annealing process, alkali ions move toward the glass surface; ② The surface easily reacts with O2, SO2, H2O and HCL; ③ The surface strength is low and Griffith cracks easily occur; ④ The glass surface is easy to carry out Ion exchange; ⑤ on the surface of the glassy Sio2 can be hydrolyzed, so that Si-O bond fracture; ⑥ surface components easily evaporate and decomposition; ⑦ surface easily crystallized;

Glass Surface Defects:

① There are pores on the glass surface or voids

Mainly due to the volatilization of the surface composition of the formation, due to alkali evaporation, the formation of the location on the surface, scanning electron microscopy, float glass surface than the lower surface (tin surface) have more protrusions and depressions

. The porosity of the glass surface facilitates the ion exchange of the glass on the surface and allows the surface to react easily with O2, SO2, H2O and HCL. As a result, the upper surface of the float glass is moldy and the surface is easily colored.

②There is a crack in the glass surface:

These cracks are not mechanical damage, but rather internal structure: low surface strength, prone to Griffith cracks.

③ Storage and transportation of moldy:

Moldy glass occurs mainly during storage or transport after packaging, which is related to packaging, storage and transportation.

Packaging can be in the hot state, cold state packaging packing paper or mold powder,

① Usually stored in a well-ventilated warehouse;

② Do not allow the glass box directly on the wet ground in the warehouse;

③ It is not allowed to store the glass outdoors and in the sunshine.