Amino resins and plastics

The English abbreviation of amino resin is AF. AF includes urea-formaldehyde (urea-formaldehyde) resin (UF), melamine formaldehyde (melamine) resin (MF), aniline formaldehyde resin, urea-melamine formaldehyde resin and urea-thiourea formaldehyde resin and many other varieties, and there are currently two kinds of UF and MF that are more widely used. The largest use of amino resins is the adhesive of particleboard and plywood, followed by coatings and fibers, and only about 10% is used in plastic products.
It has the advantages of high mechanical strength, good electrical insulation, high surface hardness, scratch resistance, colorless transparency, and can be made into brightly colored products, and is widely used in tableware, daily necessities, building electrical insulation and decorative veneer.
(1) Urea-formaldehyde resins and plastics
Urea-formaldehyde resin (UF) is formed by the polycondensation reaction of urea and formaldehyde in a certain ratio. The curing of urea-formaldehyde resin is generally formed by reaction at 130~160 °C. In order to speed up the curing speed, acid curing agents such as oxalic acid, phthalic acid and zinc sulfate can be added.
1. Urea-formaldehyde molding compound
Urea-formaldehyde molding compounds, also known as compression powder and electric jade powder, are important amino plastic varieties. The color of urea-formaldehyde molding compound products is bright, smooth and clean like jade, resistant to oil, weak acid and organic solvents, high surface hardness, odorless and tasteless.
The tensile and impact properties of urea-formaldehyde molding compounds are the best at about 0°C, and the high performance decreases rapidly with the increase of temperature, and the compressive properties and creep properties are the best at room temperature.
It has excellent electrical insulation performance and good arc resistance, and can be used for low-frequency insulation, but the electrical properties are greatly affected by temperature and humidity.
Urea-formaldehyde molding compounds can be molded by pressing and injection molding. Generally, products with simple structure are produced by pressing method, and products with complex structure are produced by injection molding.
Urea-formaldehyde molding compounds are mainly used in brightly colored daily necessities, decorations and low-frequency electrical insulation parts, such as buttons, bottle caps, tableware, hairpins, clock shells, telephone parts, electrical sockets, plugs and switches.
2. Urea-formaldehyde laminated plastic
The application of urea-formaldehyde laminated plastics is not as extensive as other thermosetting resins, and is mainly used for table and chair panels, furniture, carriages, cabins, drawing boards and building decoration materials.
3. Urea-formaldehyde foam
The main advantages of urea-formaldehyde foam are light weight, the relative density is only 0.01~0.02, less than 1/10 of cork, the thermal conductivity is very low, only 0.024~0.031W/m•K, half of that of cork, in addition, it also has corrosion resistance, and it is non-combustible after adding dihydroamine phosphate. The main disadvantages are instability to water and water vapor, low strength and poor impact.
Urea-formaldehyde foam is mainly used for building thermal insulation and sound insulation materials, and is often foamed during construction on site because of its brittleness.
(2) Melamine, formaldehyde resin and plastics
Melamine formaldehyde resin (MF) is also known as "melamine" resin, and the amount of melamine formaldehyde resin is not as large as urea-formaldehyde resin, only about half of it. The curing of melamine formaldehyde resin is similar to that of urea-formaldehyde, and can be cross-linked and cured without reinforcing agent when heated to 130~150 °C.
1. MF molding compound
MF molding compounds, also known as compression powders or melamine powders, have superior properties over UF plastics. It has low water absorption (0.15%), good insulation under humid and high temperature conditions, good arc resistance, higher surface hardness, scratch resistance, colorability, heat resistance, juice resistance and oil resistance.
MF molding compounds can be molded by both pressing and injection molding. Its main use is in the manufacture of tableware, which accounts for half of consumption, and it can also be used in daily necessities such as clocks and watches, electrical insulation materials, etc.
2. MF laminated plastic
MF laminate has excellent water resistance, high mechanical strength, heat resistance and wear resistance, and can be made into panels with color patterns, which are widely used in decorative panels such as interior wall panels of vehicles and ships, and various furniture panels.