Here in this blog, these materials also present high strength to density ratio, high resistance against corrosion, and low conductivity to electricity, magnetic fields, and heat. The matrix of an FRP composite is plastic resin.

1. Principal Types Of Polyester
Resins Used In FRP

2. • FRP stands for fibreglass reinforced plastic. This is a composite material
made of polymer reinforced with fibres. The fibres combine with a resin
matrix to form a single unit called FRP. Common types of fibres used are
glass, carbon and aramid. Many types of resin systems used in making FRP
include polyester, vinyl, epoxy, phenolic, polyurethane and hybrid.
Polyester resin for FRPs exhibits better load carrying
capacity as compared to conventional construction
materials such as steel and aluminium. These materials
also exhibit high strength to density ratio, high resistance
against corrosion and low conductivity to electricity,
magnetic fields and heat. FRPs are widely used in
constructing walkways, stairways and platforms in
industrial settings, underground piping, offshore
installations, reinforcements for concrete structures and
many more.

3. Importance of Resin
• The matrix of an FRP composite is plastic resin. The plastic resin is a
synthetic product which is different chemically from natural resin but
exhibits some of the characteristics of natural resin. The type of resin
system used in the FRP has a profound effect on its chemical, thermal and
electrical properties. The resin matrix also binds the fibres in the structural
unit.
Thermoset resins are commonly used in FRPs. These
type of resins do not melt or flow after curing.
Thermoplastic resins are uses for making FRPs for low
temperature applications. There are many types of
additives which can be added to the resin matrix to
impart extra beneficial properties to the FRP.

4. Properties of Polyester Resin
• Unsaturated polyester resin is a condensation polymer formed by reaction
of a diol such as ethylene glycol, propylene glycol or diethylene glycol with
unsaturated or saturated dibasic acid such as maleic acid or fumaric
annhydride. The resulting polyester resin for FRP is a very viscous liquid.
Thus, polyester resin comesas a combination of polyester in a reactive
monomer, usually styrene. The reactive monomer such as styrene lowers
the viscosity of the polyester resin.

5. • Polyester resins for FRP cure fast and are resistant to high temperatures
and catalysts. They also impart high dimensional stability, high chemical
resistance and good mechanical and electrical properties. Glass FRPs make
up the largest segment in which unsaturated polyester resins are used.
• There are two types of polyester resin used in FRPs: Orthophthalic and
Isophthalic resin. Both differ in many aspects which influence the type of
FRPs manufactured using these polyester resins.

6. Orthophthalic vs Isophthalic
• Orthophthalic polyester resin is used in making low cost FRPs. This is also
known as general purpose polyester. FRPs in which the resin matrix is
orthophthalic polyester resin are suitable for applications not requiring
high mechanical strength and corrosion resistance. Such FRPs cannot be
used in chemical industries because orthophthalic polyester resin has low
tolerance against chemicals. However, orthopthalic resin FRPs perform
well in water including seawater.
• Isophthalic polyester resin imparts higher strength and
flexibility to FRPs as compared to orthopthalic polyester
resin. Isophthalic polyester resin FRP panel exhibits 20%
higher tensile strength and 10% more flexibility as compared
to an FRP panel made of orthophthalic polyester resin. High
chemical resistance of isophthalic polyester resin makes it
suitable for making FRPs for use in underground petroleum
tanks and other chemical applications. Isophthalic FRPs are
also suitable for marine applications because of high water
resistance of isophthalic polyester resin.

7. Advantages of Polyester Resins
• Polyester resins for FRP provides high grade binding to the fibres in FRP
unit. The resins can tolerate temperatures up to 80 degrees C. The
shrinkage during curing is low at about 4% to 8%. FRPs made of polyester
resins provide satisfactory level of resistance to water, chemicals,
weathering and general wear and tear. FRPs made of polyester resins are
also lower in cost as compared to FRPs using other kinds of resins.

8. https://www.hasonchem.com
C-301, Copper Stone Apartment,
Opp. Oscar City, Sadhu Vasvani
Road, Rajkot – 360005.
Tel: +919033093933
Tel: +912751240365
info@hasonchem.com