Adhesive refers to a material with good bonding properties that can form a thin film between the surfaces of two objects and firmly bond them together. It is generally formulated from components such as bonding material, curing agent, toughening agent, filler, diluent and modifier.
1. Bonding material, also known as adhesive. It is the basic component in the adhesive and plays a bonding role. Its properties determine the performance, use and use conditions of the adhesive. Generally, various resins, rubbers and natural polymer compounds are used as bonding materials.
2. Curing agent. Curing agent is a component that promotes the curing of the bonding material through chemical reaction, which can increase the cohesive strength of the adhesive layer. The resin in some adhesives, such as epoxy resin, cannot become a hard solid by itself without the addition of curing agent. Curing agent is also the main component of adhesive, and its properties and dosage play an important role in the performance of adhesive.
3. Toughening agent. Toughening agent is a component used to improve the toughness of the bonding layer after the adhesive is hardened and improve its impact strength. Commonly used ones include dibutyl phthalate and dioctyl phthalate.
4. Diluent. Also known as solvent, it mainly reduces the viscosity of the adhesive to facilitate operation and improve the wettability and fluidity of the adhesive. Commonly used organic solvents include acetone, benzene, toluene, etc.
5. Filler. Fillers generally do not react chemically in adhesives. They can increase the viscosity of adhesives, reduce thermal expansion coefficients, reduce shrinkage, and improve the impact toughness and mechanical strength of adhesives. Commonly used varieties include talcum powder, asbestos powder, aluminum powder, etc.
6. Modifier. Modifiers are some components added to improve the performance of a certain aspect of the adhesive to meet special requirements. For example, to increase the bonding strength, a coupling agent can be added, and anti-aging agents, preservatives, mildew inhibitors, flame retardants, stabilizers, etc. can also be added separately.
There are many types of adhesives, and there are many classification methods. The commonly used ones are:
1. Classification by chemical composition: It can be divided into organic adhesives and inorganic adhesives. Organic adhesives are further divided into synthetic adhesives and natural adhesives. Synthetic adhesives include resin type, rubber type, composite type, etc.; natural adhesives include animal, plant, mineral, natural rubber and other adhesives. Inorganic adhesives include phosphates, silicates, sulfates, borates and many other types according to chemical components.
2. Classification by form: It can be divided into liquid adhesives and solid adhesives. There are solution type, emulsion type, paste, film, tape, powder, granules, glue sticks, etc.
3. Classification by use: It can be divided into three categories: structural adhesives, non-structural adhesives and special adhesives (such as high temperature resistance, ultra-low temperature resistance, electrical conductivity, thermal conductivity, magnetic conductivity, sealing, underwater adhesive, etc.).
4. Classification by application method: There are room temperature curing type, thermosetting type, hot melt type, pressure sensitive type, rewetting type and other adhesives.
Adhesives can be used in construction, wood, automobiles, packaging, book binding and other fields. The following focuses on construction adhesives and wood adhesives.
Construction adhesives
Adhesives are mainly used for board bonding, wall pretreatment, wallpaper pasting, ceramic wall and floor tiles, various floors, carpet laying bonding and other aspects in the process of building decoration. In addition to reflecting a certain strength, the use of adhesives in building decoration also has a series of comprehensive properties such as waterproofness, sealing, elasticity, and impact resistance, which can improve the quality of building decoration, increase beauty and comfort, improve construction technology, and improve construction efficiency and quality.
Adhesives for building decoration can be divided into water-based adhesives, solvent-based adhesives and other adhesives. Among them, water-based adhesives include polyvinyl acetate emulsion adhesives (white latex), water-soluble polyvinyl alcohol building adhesives and other water-based adhesives (108 glue, 801 glue); solvent-based adhesives include rubber adhesives, polyurethane adhesives (PU glue) and other solvent-based adhesives.
