Polyester Resin & Gel Coats

On this page you will find:

  • General information on polyester resin and gel coats
  • Special protection information
  • Effects of exposure
  • First aid procedures
  • Spill or leak procedures
  • Fire extinguishing procedures
  • Storage and handling procedures

About polyester resin & gel coats

In a composite part, the resin binds the fibres together, allows loads to be transferred between the fibres and provides a barrier to weather, water and/or chemicals.

Polyester resins used in the composites industry are made up of three main components, the base resin, styrene monomer and additives. There are many types of base resin:

  • Orthophthalic resins (ortho or general purpose)
  • Isophthalic resins (iso)
  • Terephthalic resins
  • Dicyclopentadiene resins (DCPD)
  • Neopentyl glycol resins (NPG or iso-NPG or ortho-NPG)

There are also various types of vinyl ester resin used in composites manufacturing. Vinyl ester resins are another class of base resin, which have styrene monomer and additives included, so that they can be manufactured like polyester resins.

The styrene monomer part of resin reduces the viscosity, which makes it flow better. The styrene also takes part in the curing reaction allowing the resin to turn from a liquid to a solid. Additives in resins may include any one of the following: thixotrope, pigment, filler, UV absorbers, fire retardant, inhibitor and promoter.

Gelcoats are specialised resins. Gelcoats differ from resins in that they contain pigment and usually contain less filler to give the most durable surface possible. When choosing a resin to form the base of the gelcoat, the resins with superior properties are usually chosen. The gelcoat is usually the first layer applied to the mould and its purpose is to:

  • Provide an attractive finish to the surface of the product
  • Act as a barrier against absorption of water or chemicals
  • Act as a barrier against UV radiation from sunlight which can degrade the part
  • Provide an abrasion resistant surface
  • Act as a screen against protruding surface reinforcing fibres.

The styrene monomer and in some cases the additives in polyester resins and gelcoats are relatively small in size. This allows them to be absorbed through the skin or inhaled and cause damage to the body. Polyester resins and gelcoats are also flammable.

Special protection information

Respiratory Protection: Adequate ventilation should be provided. If above NOHSC exposure standard level, use SA approved respiratory protective equipment. If dust is generated during cutting or machining/grinding/sanding of cured product, wear disposable dust mask (Type P1). Or better as determined by your risk assessment. When using resin system with fibres, use combination mask with vapour and dust particle filter.
Eye Protection: Use SA approved chemical splash goggles.
Protective Clothing: Wear chemical resistant gloves such as butyl rubber or neoprene rubber gloves. Apply barrier creams to uncovered skin. Wear full length trousers, long sleeved shirts and safety boots. CONSULT SAFETY EQUIPMENT SUPPLIERS FOR RECOMMENDATIONS.

Effects of exposure

Eyes: Can cause severe irritation and redness.
Inhalation: Can cause upper respiratory tract irritation, nausea and CNS depression. Severe over-exposure can lead to death by suffocation.
Skin: Can cause moderate irritation – defatting and dermatitis.
Swallowing: Can cause CNS depression and stomach upset. Aspiration of material can cause potentially fatal damage to the lungs. Some formulations are carcinogenic.

First aid procedures:

Eyes: Flush with water for at least 15 minutes.
Inhalation: Remove to fresh air. If breathing is difficult, seek immediate medical assistance.
Skin: Wash with soap and water. Do NOT use solvents.
Swallowing: Do NOT induce vomiting. If person is conscious, they should drink large quantities of water. Seek medical advice immediately.

Spill or leak procedures

Eliminate all sources of ignition and ventilate area. Wearing protective equipment, stop spill at source, dam area and, if possible, pump liquid into salvage tank. Alternatively, absorb spill with vermiculate or sand. Scoop up using non-sparking tools into labelled waste container. Dispose of waste in accordance with local, state and federal regulations. Seek advice from supplier. Reporting of spills/leaks may be required under EPA and Dangerous Goods regulations.

Fire extinguishing procedures

Wear protective equipment including selfcontained breathing apparatus. Use foam, dry chemical or carbon dioxide to put out fires. Avoid use of direct stream of water. Product may float or re-ignite. Cool fire exposed containers with water spray.

Storage and handling procedures

DG Class 3 (Flammable liquid). Store properly in closed, labelled containers in a cool, well ventilated area. Keep away from sources of ignition and oxidizing agents. Earth containers when pouring to prevent discharge of static electricity. Do not transfer to unmarked containers. Provide both floor level and breathing zone ventilation.

KEY to abbreviations – CNS: Central Nervous System EPA: Environmental Protection Authority NOHSC: National Occupational Health & Safety Commission (Worksafe Australia) PVC: Polyvinyl chloride SA: Standards Australia

Disclaimer: Facts and information reported on this page are believed by Composites Australia to be accurate at the date of printing. No responsibility is accepted by Composites Australia for the use or misuse of information on this page. Composites Australia accepts no responsibility for damage or injury caused by information or omissions contained on this page.