Bookbinding hot melt adhesive

[China Aluminum Industry Network] Currently, energy conservation and environmental protection have become one of the themes for humans to improve the living environment and society seeks healthy development. With the continuous development of economic development and people's quality of life, building energy consumption has accounted for more than 40% of the national energy consumption and has become a non-negligible part of energy consumption. Doors and windows as an indispensable part of the building envelope structure can ensure the lighting and ventilation of the building, improve the aesthetics of the building and the comfort of living, but at the same time, it is also a factor that consumes more energy in the building envelope structure. Studies have shown [1,2] that in building energy consumption, the energy consumption caused by glass doors and windows accounts for about 50% of the total energy consumption of buildings; among them, energy consumption analysis of multi-story buildings in the literature [3] shows that doors and windows Heat dissipation accounts for more than one-third of the total heat dissipation of the building. Therefore, improving the energy-saving performance of doors and windows has become the key to building energy efficiency. Energy-saving doors and windows that use new energy-saving materials, efficient insulation systems, and lighting, sunshade design and other energy-saving technologies can reduce the energy loss of the entire building by nearly 40% [4]. Aluminum doors and windows with thermal insulation and breakage are favored by the majority of owners because of their excellent energy-saving, sound-proof, noise-proof, dust-proof and waterproof functions. In the production process of such doors and windows, there is an inevitable need for cutting and assembly processes. Simply relying on precision cutting equipment, proper corner connections and corners of the door and corners of the unit corners, it is easy to be damaged by various forces during production, transportation, installation and long-term use.[5] . The use of a special group of corner glue can effectively solve the problem of corners of aluminum doors and windows, improve the heat insulation, airtightness, watertightness, sound insulation and other properties of aluminum doors and windows, and ensure the energy saving effect of aluminum doors and windows. This article summarizes the reasons for the formation of the corners of the aluminum doors and windows, the role and characteristics of the group glue, and the status quo of the application technology of the corner glue.

1 Causes of Corner Problems

1.1 Temperature difference

The material itself usually causes a certain stress due to the change of temperature, which shows a linear expansion/contraction rate.

The dimensional change of the aluminum alloy profile within the normal operating temperature range, ie, the linear expansion/contraction rate, is calculated as:

In the formula - the length after the change;

- the original length;

- The expansion / contraction coefficient, in the range of -40 - 50 ° C, the value of 2. 4 × 10-5 ° C;

- Celsius temperature changes.

Calculated by the formula, the change amount of 1m long aluminum alloy profile under the temperature difference of 90°C in the range of -40°C to 50°C: This 2.16mm change rate is enough to make the parts of the door and window corners misaligned or deformed, resulting in corners. Department of strength and sealing performance, energy saving is no longer talked about.

1.2 External Force

Many unavoidable, unavoidable inevitable and accidental external forces cause deformation stresses that can lead to corners of doors and windows. For example, during production, transportation, and installation, various degrees of collisions and knocks are generated; doors and windows are installed. After a long period of time, its static weight is affected by its own weight and the deformation of window openings and walls; vibration effects such as opening and closing windows, wind pressure, and environmental sound waves are also affected. These can lead to airtight doors and windows, heat insulation, sound insulation, dust performance decreased, in serious cases will cause deformation of doors and windows, becoming the main reason for the energy consumption of doors and windows.

The role and characteristics of 2 sets of glue

In order to solve the problem of the corners of aluminum doors and windows, to produce aluminum doors and windows that meet the energy-saving performance requirements, an effective method is to use a corner sealant designed for doors and windows (referred to as the corner glue), the corners or inserts and profile cavity The wall is bonded to form a structure to strengthen and seal, to avoid the door and window frame due to temperature and external force deformation caused by dislocation deformation, thus ensuring the doors and windows of airtight, heat insulation, noise, dust and other properties.

Therefore, the performance of the adhesive is required to meet: (1) high hardness, high strength, good toughness, can make the structural connection between the corner and the profile wall, and also have excellent waterproof performance; (2) Slightly foaming and expanding to form an elastic pad between the metal and the metal to weaken the conduction of various forces and act as a shock absorber and a buffer pad. (3) It has better aging resistance and can withstand -40°C. 80°C temperature change.

At present, professional group of rubber adhesives are mostly polyurethane sealants. Polyurethane rubber structure contains very polar and chemically active -NCO (isocyanate), -NHCOO- (urethane groups), has excellent chemistry for materials such as metal, glass, plastic, etc. Adhesive force, high strength, hardness and excellent impact resistance, suitable for a variety of structural bonding areas, through the formulation and process design can meet the performance requirements of the group of angle glue.

The application status and development prospects of 3 groups of Adhesive Glue

3.1 Status of Application Technology of Group Glue

With the implementation of energy conservation and consumption reduction measures in China, the building industry gradually takes the renovation of doors and windows and energy-saving design as an important development direction of building energy efficiency. Therefore, the application of group glue is getting more and more attention. However, due to the late development of energy-saving technologies for doors and windows in China, there are still many problems in the application of corner glue in door and window groups.

The first is the problem of counterfeit compound glue. The above mentioned that professional group glue is a kind of polyurethane sealant that can meet the performance requirements, with high hardness, high strength, good resistance to aging and so on. Some door and window factories mistakenly use silicone adhesives, epoxy adhesives, and the like as aluminum alloy door and window adhesives. Silicone adhesives have very low hardness and high elasticity when they are cured. Colloids do not swell when cured. It is closely integrated with the cavity; however, the epoxy glue is not elastic after being cured, and it is easy to be crumbled and broken. It can not adapt to the form of microseism, and it will cause cracking and dregsing after long-term use.

The second is that many manufacturers do not completely establish a unified standard production process. The requirements for the construction time and curing speed of the compound glue are different. To select a suitable compound glue, we can better ensure product quality. According to investigations, currently there are two main production processes for the production of plastics and door glues for group applications, namely the open injection process and the overall injection process. (1) Open glue injection process: Direct extrusion of the corner glue near the inner surface of the profile cavity, insert the corner code, connect two sections of the profile, the angle of the upper set of corner units can be fixed, the process requires sufficient construction time, In order to prevent the assembled adhesive glue from being assembled, it can not work effectively; (2) Integral rubber injection process: directly insert the corners to connect two sections of materials, and the upper group of corner units is fixed and prefabricated to the inside of the prefabricated hole. The glue is injected until the glue is overflowed at the carding point. This process is a standardized production process that is currently being vigorously promoted. It requires that the corner glue be quickly cured in a closed environment. Generally, two components are used to cure the two components. Polyurethane corner glue, and one-component polyurethane corner glue, rely on room temperature moisture curing, curing is relatively slow, generally do not recommend.

Again, based on the market demand for the design of polyurethane adhesive, one-component and two-component products are very different in terms of technical parameters. For example, the single-component adhesive is easy to operate and convenient to construct. Generally, it can be completely cured after seven days. The shear strength can reach 6MPa or more, and it can expand after being cured. The two-component adhesive needs a special glue-making equipment. Fast curing, short construction time, hardness after curing up to shoreD70 - shoreD80, shear strength can reach 10MPa or more, after curing can be slightly expanded but not foaming. It can be seen that the single component angle has better shock absorption and buffering effects, but the curing is slow, and the effect on the production efficiency and corner strength is far inferior to that of the two-component adhesive. At present, there is no real evidence to prove which group of corner glue is more effective.

The latter is the lack of authoritative industry standard specification group performance indicators, while the technical description often only describes dry time, construction time, curing speed, and final shear strength. It is difficult to ensure that the corners of windows and doors are in the long term. There is no problem during use. Based on investigations and investigations, our company adopts harsh high-temperature and high-temperature and high-humidity aging projects, and consults technical specifications, construction guides, and test reports of similar foreign products, citing climate change, cold strength, thermal strength, and other performance indicators. The company's standard Q/ZZY 037-2015 "Building doors and windows with polyurethane adhesive". According to the inspection of Q/ZZY 037-2015, the performance of our company's group Jiaojiao is basically the same as that of similar foreign products. It has excellent heat resistance and heat and humidity resistance, and the attenuation rate after high-temperature aging does not exceed 10%. The decay rate after aging does not exceed 25%. Individual domestic brands, after being treated with high temperature and high temperature and high humidity aging items, have an attenuation rate of 80% and almost no basic bonding effect.

3.2 The development prospects of the group glue

The issue of resources has become a worldwide problem, and the construction industry is no exception. Doors and windows are also moving in this direction through continuous reforms. At present, the proportion of developed countries using high-performance energy-saving doors and windows has reached 70% of the total amount of doors and windows. In China, high-performance energy-saving doors and windows account for only 0.5% of the total amount of doors and windows. The low penetration rate of energy-saving doors and windows has caused China’s building energy consumption to be far greater than that of developed countries. With the deepening of the concept of energy conservation and environmental protection, energy-saving doors and windows will be greatly promoted and applied. The application of group glue is also highly valued.

Each year, China has about 2.1 billion square meters of housing construction, which is equivalent to the sum of Europe and the United States. Usually the area of doors and windows in the building area accounts for about 25% - 30%, according to this projection, China has about 500 million square meters of doors and windows per year. According to the calculation of the amount of glue used per square meter of door and window group is about 0.1kg, the amount of glue used in each group is about 50,000 tons, and the demand is huge. Adapting to changing market demands, continuously improving and optimizing corner glue and breaking foreign monopolies are of great significance in promoting the development of energy-saving doors and windows, and will inevitably form good economic and social benefits.

4 Conclusion

The corner glue is designed for aluminum alloy door and window corner structure reinforcement and sealing. It can meet a variety of assembly angle requirements and can effectively improve the performance of aluminum alloy doors and windows such as heat insulation, airtightness, watertightness and sound insulation. The use of a special group of adhesives to create a high level of aluminum alloy doors and windows products will effectively promote the development of energy conservation in China's doors and windows.

references

[1] LI Na, XU Jinhua. Application of energy-saving doors and windows in buildings. Building Energy Efficiency, 2008(5):49-51.

[2] Zhu Wenpeng. Research and application of energy-saving windows. Architecture Technology, 2001 (10): 673-675.

[3] Chen Hongbing, Li Deying et al. Study on the effect of windows on building energy consumption. Journal of Beijing Institute of Architecture and Engineering, 2004.20 (4): 9-11.

[4] Zhan Xingqiong. Application and control measures of energy-saving technology for building curtain wall windows and doors. Industrial Design, 2016(3): 155-156

[5] Wang Yongbo. Corner structure strengthening and sealing of aluminum alloy doors and windows. Hebei Coal, 2007(3):53-54