Unsaturated Polyester Resin

Unsaturated Polyester Resin (UPR)** is a thermosetting resin that is widely used in construction, transportation, marine, electronics, and electrical applications. It is mainly a cross-linked material formed by the polymerization reaction of an unsaturated dibasic acid (e.g., maleic anhydride) with a diol (e.g., ethylene glycol) to produce a polyester, which is then copolymerized with a vinyl monomer (usually styrene).
1. Basic Information:
Chemical name: Unsaturated Polyester Resin (Unsaturated Polyester Resin)
Appearance: light yellow transparent or semi-transparent liquid at room temperature, hard solid after curing.
Composition: Unsaturated dibasic acid (such as maleic anhydride), saturated dibasic acid (such as phthalic acid), dibasic alcohol (such as ethylene glycol) and vinyl monomer (styrene) copolymerization composition.
Curing method: Add initiator (e.g. methyl ethyl ketone peroxide, MEKP) and cure by room temperature or heat.
2. Physical properties:
Viscosity: 500-2000 mPa.s (according to different product formulations)
Solid content: 35%-70% (depending on product type)
Gel time: 5-30 minutes (depending on the initiator and ambient temperature)
Tensile strength: 40-100 MPa
Flexural strength: 80-150 MPa
Hardness: Barcol hardness can reach 40-50
Water absorption: low, with good moisture resistance.
3. Product type:
Unsaturated polyester resins can be classified into the following categories according to usage and performance:

Standard UPR: suitable for the production of general FRP products.
Reinforced UPR: enhanced mechanical strength, suitable for the manufacture of high-strength composite materials.
Flame-retardant UPR: Contains flame retardants and is suitable for applications where fire resistance is required.
Low shrinkage UPR: suitable for the manufacture of high surface quality products.
Corrosion-resistant UPR: Suitable for chemical equipment and anti-corrosion materials.
4. Application fields:
FRP products: such as ship hulls, yachts, car body parts, storage tanks and pipes.
Building decoration materials: such as artificial stone, decorative panels, sanitary ware products.
Anti-corrosion equipment: such as chemical storage tanks, chemical equipment lining.
Coatings: for industrial anti-corrosion coatings, floor paints, etc.
Mould making: used in the production and manufacture of precision molds.
5. Packaging and storage:
Packing: usually packaged in 25kg or 200kg iron or plastic drums.
Storage: Store in a cool and ventilated place, avoid direct sunlight and prevent contact with open flame. Usually storage temperature is 15°C-25°C, avoid too high temperature leading to early curing.
Shelf life: usually 3-6 months, depending on storage conditions.
6. Caution:
Avoid prolonged contact with moisture in the air and UV rays during use to avoid affecting the curing effect of the resin.
Protective gloves and masks should be worn during operation to avoid skin and eye contact with unsaturated polyester resin and its volatile styrene monomer.