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Analysis of quality identification and quality control ways of insulating glass

In recent years, the insulating glass industry has developed rapidly, and its penetration rate in glass curtain wall industries has increased. However, due to the lack of basic theory of insulating glass in some developing countries and the actual service life of insulating glass does not reach the time limit mentioned in the publicity at all, it has already expired.

Some glass curtain walls failed after only 10 years after they were built, resulting in hidden frame curtain walls that are likely to have safety accidents. This not only failed to achieve the purpose of energy-saving and efficiency enhancement but also increased a lot of social costs. This article introduces several simple methods to distinguish the pros and cons of insulating glass, for readers' reference only.

If any piece of insulating glass is extracted from the finished product, and any one of the following phenomena is found, the consumer can judge it as an unqualified product and request a return.

1. Use a knife to cut the second seal into a cross-section. If there are many small pores (small honeycombs) in the cross-section, this indicates two possibilities. One is manual gluing, which entraps air and produces bubbles; the other is to use the secondary sealant produced by low-level technology will have pores even if it is glued by a machine. As long as there are pores in the cross-section, its life will be very short.

2. Use a knife to cut any joint corner of the insulating glass to see if the joint corner is effectively wrapped with butyl glue. The actual theory shows. The double-channel sealed insulating glass made by the connecting angle method has the water permeability path mainly at 4 corners, and its water permeability is 70%, while the edge water permeability only accounts for 30%. So try to use continuous elbow aluminum strips or use butyl glue to effectively wrap the 4 connecting corners, which can greatly extend the service life of the insulating glass. If the 4 corners are not effectively wrapped with butyl glue, double-sealed The actual meaning is not great.

3. Use a knife to cut the two sections of the second seal and glass bonding a few centimeters, and then tear the sealant outward by hand. If the surface of the glass is relatively smooth after tearing, there is no residual glue, indicating that the sealant and the glass surface have no adhesion, then the sealing effect can be imagined.

4. Supplement the above methods to check whether standard molecular sieves are used, whether the butyl rubber is continuous (without disconnection), if it is not polysulfide, whether the other two sealants have been tested for compatibility (must be compatible with Experiment, otherwise it is likely to have endless troubles). If the window frame is not sealed with standard rubber strips, but with ordinary silicone rubber, the compatibility test of the silicone rubber and the edge sealant of the insulating glass must be done, otherwise, there may be endless troubles (some door and window installations) The company purchases low-quality oil-extended silicone rubber to seal the window frames. Over time, mineral oil migrates out and erodes the entire insulating glass sealing system. Since it takes a while for this evil effect to manifest, it must be prevented in advance).

Figure 1 the difference between the plug-in corners of insulating glass 1

Figure 1 the difference between the plug-in corners of insulating glass 1

Related articles about the compatibility experiment of insulating glass secondary sealant using silicone glue, please refer to the following article for the experiment process and results: 

The performance comparison analysis report of polysulfide glue and silicone glue for insulating glass

Although the basic theory of insulating glass in some developing countries is not perfect at present, the rapid development of insulating glass in some developing countries in recent years and various types of insulating glass production equipment has been widely used in production practice. At the same time, in the nearly 20 years of insulating glass development history, it has accumulated a lot of practical experience in both positive and negative aspects. Jinan LIJIANG Glass now summarizes the following quality control methods as follows.

1. A better process is an effective way to improve the quality of insulating glass. 

For the insulating glass industry, a good production process must have the following requirements. 

First, a continuous and stable-working insulating glass production line. Only a continuous production line can ensure that the insulating glass products have the consistent quality from the original glass to the qualified finished product, and can maximize the production efficiency; 

Second, whether it is the first Road sealing is still the second sealing equipment. Sealing equipment with a high degree of automation should be used as much as possible. Only in this way can the impact of human factors on quality be minimized.

2. Improve the production environment of insulating glass. 

The insulating glass must be produced in an environment free of dust, solvent pollution, and suitable temperature. Dust pollution in the production workshop will have a great adverse effect on the bonding effect of each component of the insulating glass sealing system. The sealing performance and functional life of hollow glass products with poor bonding effects can be imagined. Due to the presence of solvents, the butyl rubber (PIB) will lose its adhesion, and the first seal will fail. Therefore, do not use volatile substances in the workshop and keep the air unobstructed. A suitable temperature is a necessary condition for the formation of effective results for the second seal. The supply temperature of the second sealant should be kept above 10℃ as far as possible. Only a suitable temperature can allow the sealant to achieve the use effect within the specified time, such as initial adhesion. Relay, shear strength, elastic modulus, sealing performance, etc.

3. With excellent insulating glass production equipment

A good production environment, and good management, you will never be able to make insulating glass with stable quality and excellent performance. The particularity of insulating glass production determines that the following aspects of management are particularly important.

①Aluminum strips are connected by plug-in angle type, check whether the 4 connection angles are effectively sealed with butyl rubber (PIB);

②Whether the molecular sieve is filled with the second sealant within 40 minutes specified in the regulations;

③Whether the coated glass that needs to be edged meets the edging requirements;

④Whether the width and thickness of butyl rubber (PIB) and secondary sealant meet the required values of relevant standards;

⑤Whether the second sealant has been tested for compatibility with silicone sealant (according to the insulating glass sealant industry standard, if the second sealant uses silicone rubber, the compatibility test should be performed).

For how to choose excellent insulating glass production equipment, please refer to the following links:

Manual insulating glass two-component sealant sealing machine
Automatic insulating glass sealing robot machine

4. Choosing qualified supporting materials is a necessary and sufficient condition for the production of qualified insulating glass. 

It is impossible to produce high-performance hollow glass products without qualified supporting materials. Therefore, the selection of materials is a very critical link. According to the current domestic production status of insulating glass, double-pass sealing is the mainstream production process, and other processes are in a complementary position. Therefore, the quality of the various components that constitute the double-pass sealing process is the focus of people’s discussion and constitutes the main component of the double-pass sealing process. There is butyl rubber (PIB), polysulfide rubber, silicone rubber, aluminum strips, desiccants, connectors, etc., as a relatively mature and reliable double-channel sealing process formed by butyl rubber + polysulfide rubber, due to energy-saving The door and window industry has been successfully used for more than 25 years, so it has been recognized by the industry as the first choice for the production of high-airtight hollow glass products.

With the continuous innovation and development of modern architecture, the emergence of glass curtain walls puts forward higher requirements on the double-pass sealing process of insulating glass. The insulating glass of curtain walls must not only show beauty but also achieve energy-saving effects within the functional life. At the same time, it is necessary to reflect the safety performance. Since silicone rubber has excellent properties such as UV resistance and shear strength, it has become the first choice for the secondary sealing material of insulating glass for hidden frame curtain walls. To ensure the functional life of its sealing, the thickness of the glue layer should be listed as the content of designer’s main considering, this is mainly because although silicone rubber has excellent aging resistance, its airtight performance is relatively insufficient, especially once the manufactured hollow glass has water vapor in it, the functional life of the hollow glass will immediately end. The moisture condensed in the hollow glass will have a fatal impact on the entire hollow glass component, which in turn will cause the production of non-safety factors, which will increase the social cost. 

Figure 2 The moisture condensed inside the insulated glass 1

Figure 2 The moisture condensed inside the insulated glass 1

Therefore, the appropriate thickness of the adhesive layer is designed to extend the functionality of the sealant. The best choice, which is to ensure the safety of curtain wall insulating glass and extend its functional life. Compatibility experiments on various sealing materials and the use of bendable aluminum strips and molecular sieves with appropriate adsorption rate as much as possible are also effective ways to control the quality of the insulating glass and extend the functional life.

For more information about Jinan LIJIANG Glass insulating glass processing equipment and insulating glass processing accessories, please click here to learn more. 

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