Types of adhesives
Early human civilization knew to use natural materials such as batter, animal glue and asphalt to connect various materials. When the synthetic adhesive appeared, it was like “paper instead of bamboo slips” and integrated into our life.
The adhesive is suitable for the connection of different materials, different thicknesses, especially ultra-thin materials and complex structural parts. Bonding between automobile parts, laminating of food packaging, fitting of clothing cloth / cloth & cloth / film, splicing of home decoration plates It can be said that adhesive involves all aspects of “food, clothing, housing and transportation”, and plays an indispensable role.
What is adhesive?
A kind of organic or inorganic, natural or synthetic substance that can connect the same or two or more homogeneous or heterogeneous parts (or materials) together and have sufficient strength after curing, collectively referred to as adhesive or adhesive, adhesive, or customarily referred to as adhesive.
The adhesive consists of main agent and auxiliary agent:
Main agent: such as synthetic resin (the largest amount of binder), rubber and elastomer, natural polymer, inorganic binder, etc
Auxiliaries: such as curing agent, solvent, plasticizer, filler, toughener, coupling agent, etc
Types of adhesives
Pollution sources of adhesives
The environmental problems of adhesives are mainly environmental pollution and human health hazards, which are caused by harmful substances in adhesives, such as toxic and harmful solvents, auxiliaries, volatile organic compounds, etc.
Volatile organic compounds (VOC)
Toxic and harmful substances
Some poisonous fillers
Environmental protection is the key to ensure the sustainable development of economy and the healthy survival of human beings in the 21st century. The adhesive industry is responsible for the environmental impact. It is advisable to take effective measures as soon as possible.
First of all, we need to change the traditional concept, not only focus on the immediate local interests, but ignore the damage to the ecological environment; not only focus on the temporary economic benefits, but at the expense of the environment. The adhesive industry should pay attention to social and environmental benefits while pursuing economic benefits, and make new contributions to environmental protection.
- Develop environmental friendly adhesives
In order to avoid environmental pollution and ecological damage, it is imperative to develop environmental friendly adhesives with low pollution or no pollution. The so-called environmental friendly green adhesive refers to the adhesive that has no pollution to the environment, no toxicity to human body and meets the three requirements of “environmental protection, health and safety”.
The water-based adhesive is made by using water as solvent or dispersing medium. Because no organic solvent is used, the solvent pollution is eliminated. It should be noted that not all water-based adhesives are pollution-free, for example, urea formaldehyde adhesive and 107 adhesive are also water-based adhesives, but the pollution is very serious. Water based laminating adhesive has begun to replace solvent based laminating adhesive, which is non-toxic, non combustible, pollution-free and safe to use.
Solventless means that there is no solvent in the adhesive, because no solvent volatilizes to the atmosphere, it will not cause pollution and harm. The vast majority of epoxy adhesive, anaerobic adhesive, α – cyanoacrylate adhesive, aerobic modified acrylate structural adhesive, solventless polyurethane adhesive and light curing adhesive are all solventless.
The solid form of adhesive is used in solid form, such as hot-melt adhesive, hot-melt pressure-sensitive adhesive, water-soluble powder adhesive, reactive rod-shaped adhesive, solid adhesive rod for office use, etc. there is no volatiles released during the coating and bonding process, and there is no environmental pollution at all.
Adhesive belongs to the new field of fine chemical products, has always been playing the “best supporting role” in our lives, creating infinite value for us, but it is often ignored and forgotten. Finally, the focus of attention is environmental pollution and health hazards. But with the development of environmental friendly adhesive, we hope to recognize it again.