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​Knowledge Of Glass Life

Common glass (sodium calcium glass) has no "aging" problem in the natural environment.

The chemical composition of glass is very stable. In the natural state, the glass is not affected by the sunlight and rain fog. The common acid base is not harmful to the glass, and we think about the chemical laboratory utensils of reading.

Usually the glass life is affected only by two, humid air and high temperature. Continuous moist air can make the glass mould, but under the situation of the glass mould speed is very slow, usually need a couple of months, there are very few in normal use environment moist air in the last few months, so the glass exposed in air is not going to happen the mildew. The mildew of general glass occurs in glass overlapping stored procedure, the glass is in damp storehouse inside or open stacking the rain is more prone to musty change. In general, the untempered glass is more likely to be mildewed than tempered glass.

Don't consider the factor of thermal cracking, below 300 ℃ temperature has no effect on the stability of glass life and chemistry. But as temperatures above 300 ℃, the chemical and physical properties of the glass will change with the increase of temperature. In physical terms, the average glass begins to soften at about 600 degrees. In terms of chemical properties, the temperature rise causes the glass to produce the crystallization phenomenon, so that the glass gradually changes from transparent to fuzzy. Under the condition of 700 ℃ lose transparent glass crystallization process need a few days, in the case of a 300 ℃ may require months or even years. In the case of normal temperature, it may take thousands of years to crystallization of glass, so it is not considered.

The life of tempered glass

Physical steel is to heat the glass before it is cold, changing the structure between the molecules and the molecules in the glass. Chemical steel is used to exchange the molecular structure of the glass surface at high temperature. Both are permanent changes in the microstructure of glass materials. Therefore, unless there is a high temperature and reinforcement, the characteristics of steel under normal use will not attenuate or change with the change of time.


The life of the insulating glass

Hollow glass is a combination of glass substrate, spacer frame (aluminum bar), desiccant (molecular sieve), sealing material (butyl glue, polysulfide or structural glue). In the composition of insulating glass, glass and aluminum frame are usually very stable, and the life of insulating glass depends on the life of molecular sieve and sealing material.

In the composition of the hollow glass system, the glass is very stable, and the glass substrate we talked about in the past is basically normal use without considering the aging problem; Standard hollow recommended aluminum bars are treated with surface anodization. The physical and chemical properties of aluminum bars treated with surface anodization are very stable under normal conditions. Even if there is no aluminum strip treated with surface anodization, the aluminum strip will lose its luster during the process of use, but it has no significant effect on the performance of the aluminum bar itself.

For hollow glass, we should see that the value of the hollow system construction is that the insulating and dry hollow glass can be insulated and soundproof. Due to the change of environmental temperature of gas is always empty cavity is in a state of expansion or compression, make hollow glass sealing system always is in a state of stress, and at the same time, the ultraviolet ray in the environment, water and moisture will accelerate the aging of sealing systems, leading to water vapor to accelerate into the empty cavity. The hollow glass has been invalidated by the large amount of water vapor in the empty glass cavity, and the failure of insulating glass means that the service life of insulating glass is terminated. The key to ensure that insulating glass is not lapsed is desiccant and sealant.

As for the life of insulating glass, the concept of 10-year warranty period is given by the first Chinese glass enterprise reference American standard. In the standard GB/T11944-2012, the concept of "life expectancy of hollow glass should be greater than 15 years" was proposed for the first time. , in fact, the service life of hollow glass and hollow glass material selection, processing technology have close relations, hollow glass layout structure, using the environment at the same time the influence of many factors, such as simple difficult to quantify. For the insulating glass that has been installed on the wall, the simpler measure is actually the dew point or the interval layer air humidity.

The life of low-e glass

The life of low-e glass depends on the life of the hollow sealed system. We know that the main components of the low-e film layer are metals, alloys, metal oxides and metal nitrides. Metal nitride is generally used as the protective layer in the membrane structure, and its performance is very stable. The metal oxide and alloy layer are generally used as the medium layer in the film layer to connect the silver layer and the protective layer, and the properties are also stable. The silver layer in low-e is relatively active, but its oxidation is conditional on the need for water vapor.

So as long as the insulating glass does not fail, the life of the low-e film layer is not considered separately.

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The life of the laminated glass

The laminated glass is a compound glass product which is sandwiched between the glass and a layer or layer of organic polymer, which is processed by the process to make the glass and the intermediate film permanent. The laminated glass can be glued to the film even when the glass is broken, effectively preventing the debris from puncturing and penetrating the falling event to ensure the safety of the person.

The life of the laminated glass depends on the intermediate layer of the interlayer. Normally wet process laminated glass and EVA laminated glass are mainly used for indoor partition, not applicable to building doors and Windows or curtain walls. Wet - layer glass and EVA laminated glass will accelerate aging under the sun exposure. After 1-2 years, there will be a yellowing phenomenon. In 2-3 years, there will be a number of degumming bubbles, ice flowers and fog. Generally speaking, the speed of the wet process of laminated glass is much faster than the EVA sandwich glass. EVA laminated glass prevents direct sunlight from being used indoors for more than 10 years.

The PVB and SGP laminated glass used as Windows or curtain walls are much better. The most typical failure of the sandwich glass PVB and SGP is the gelatine, which means that the glass and the spacer are removed, and the security features of the laminated glass are lost. The life of PVB and SGP sandwich glass is not standard and standard in China. At present, domestic glass processing enterprises generally refer to foreign PVB and SGP supplier related materials to give the product quality guarantee period of 5-7 years.

In fact, the life of PVB and SGP sandwich glass, besides being influenced by the middle layer material, the thickness of the mesointerval layer, the quality of the laminated glass substrate and the control of the sandwich glass process control are very influential.

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