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ISO Polyester Resin — isophthalic unsaturated polyester resin; Samrat Poly Resins product graphic
ISO Resins

ISO Polyester Resin

Isophthalic unsaturated polyester resin for laminates facing water immersion, chemical service or sustained outdoor conditions.

Price

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Industrial resin pricing varies based on:

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  • Resin Grade
  • Current Raw Material Rates
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Product details

Product RoleIsophthalic unsaturated polyester resin
Colour / AppearanceOff-white to light beige liquid
Acceleration StatusNon-accelerated
Packaging225 kg industrial drum
Shelf Life3 months
Storage Temperature15–25 °C
Country of OriginIndia

Technical specifications

Resin TypeIsophthalic Unsaturated Polyester Resin
Curing SystemMEKP catalyst with cobalt octoate accelerator
Recommended DosageMEKP 1.5% and cobalt octoate 0.4% by weight of resin
Viscosity500 cPs (mPa·s) at 25 °C
Gel Time15 minutes at 25 °C
Peak Exotherm190 °C, reached in 25 minutes
Specific Gravity1.12 g/cm³ at 25 °C
Styrene Content40% by weight
Acid Value16 mg KOH/g
Heat Deflection Temperature90 °C (cured resin)
Tensile Strength / Modulus75 MPa / 3,500 MPa (cured resin)
Elongation at Break3.0% (cured resin)
Flexural Strength / Modulus125 MPa / 3,700 MPa (cured resin)
Barcol Hardness42
Water Absorption0.15% by weight after 24 h
Flash Point34 °C, closed cup

ISO Polyester Resin is an isophthalic unsaturated polyester resin manufactured by Samrat Poly Resins. Isophthalic resins are built on isophthalic acid rather than the phthalic anhydride used in general-purpose orthophthalic grades. In general industry terms that difference allows a higher-molecular-weight polyester chain, which is why isophthalic resins are normally specified where a laminate faces water immersion, chemical service or sustained outdoor conditions rather than routine dry FRP work. Samrat Poly Resins supplies this grade for those more demanding FRP applications.

Where the requirement is routine general-purpose FRP lamination rather than chemical or water service, our orthophthalic grades such as GP Clear Resin and Unsaturated Polyester Resin are the usual route. Where the service medium is aggressive and a stated chemical-resistance requirement applies, review Vinyl Ester Resin as well. Share the FRP component, service medium and operating condition with your enquiry so the right grade can be confirmed.

Key features

  • Isophthalic backbone rather than the orthophthalic chemistry used in general-purpose grades
  • Positioned for chemical, water and hydrolysis resistance in FRP service
  • Room-temperature cure with MEKP catalyst and cobalt octoate accelerator
  • Supplied in 225 kg industrial drums
  • Manufactured by Samrat Poly Resins at Doraha, Punjab

Applications

  • Laminates facing water immersion or sustained damp service
  • Chemical service FRP where a resistance requirement applies
  • Components in sustained outdoor conditions
  • Tanks, linings and corrosion-resistant FRP

Industries we serve

  • Chemical process & storage
  • Marine & boat building
  • Water & effluent treatment
  • FRP & composites manufacturing

Why choose Samrat Poly Resins

  • ISO 9001:2015 certified quality management system
  • GST-registered Indian manufacturer (GSTIN 03ALBPS3446G1ZB)
  • Dispatch across North & East India, with exports to Nepal and Bangladesh
  • Enquiry can begin with the FRP component, service medium and expected quantity

Frequently asked questions

It is an isophthalic unsaturated polyester resin — a resin built on isophthalic acid rather than the phthalic anhydride used in general-purpose orthophthalic grades. Samrat Poly Resins supplies it for FRP work that needs better chemical and water resistance than a standard GP resin.

No. In resin naming, ISO is short for isophthalic and describes the chemistry of the resin. It is unrelated to ISO 9001:2015, the quality management system standard Samrat Poly Resins is certified to. The two terms mean different things.

The difference is the diacid used to build the polyester chain — isophthalic acid instead of phthalic anhydride. General industry literature attributes better hydrolytic stability, chemical resistance and heat distortion performance to isophthalic resins, which is why they are normally specified for immersion and chemical service. Confirm the requirement for your component with us before selecting.

Vinyl ester is a further step for aggressive chemical service. Vinyl Ester Resin is Samrat's documented bisphenol-A epoxy vinyl ester grade. Share the service medium, concentration and temperature and we will advise which route fits the duty.

No. ISO Fire Retardant Resin is an isophthalic grade formulated for fire performance. This grade is the general isophthalic resin without that fire-retardant package.

Yes. The Technical Data Sheet for this grade (SPR-TDS-IPR) can be downloaded from this page and from the technical document library.

Isophthalic resin selection

ISO Polyester Resin guides

These guides cover what the isophthalic backbone actually changes, where the grade is genuinely specified, the alkali limit that decides when to step up to vinyl ester, and what to send with an enquiry so a grade can be matched to a real service condition.

What Is ISO Polyester Resin? Isophthalic UPR Explained

ISO Polyester Resin is an isophthalic unsaturated polyester resin. Understand what the isophthalic backbone actually changes, why it resists water and chemicals better than a general-purpose grade, where it is specified, and what ISO does and does not mean in this product name.

14 min readRead Article →

ISO Polyester Resin Applications: Where Isophthalic Grades Are Used

Where isophthalic polyester resin is genuinely specified: chemical tanks and bunds, process pipework and ducting, marine skin coats, water and effluent equipment, sanitaryware, pultrusion and filament winding, and how the laminate is built in each case.

6 min readRead Article →

ISO Polyester Resin vs GP Resin: When Is the Step Up Worth It?

Isophthalic and orthophthalic resins look and handle almost identically in the workshop. Understand what actually changes in the backbone, where the difference shows up in service, and the cases where paying for isophthalic is simply wasted.

5 min readRead Article →

ISO Polyester Resin vs ISO Fire Retardant Resin

Two Samrat products share the ISO prefix and are routinely confused. Both are isophthalic, but only one is formulated for fire behaviour. Understand what each ISO means, how fire retardancy is actually achieved, and which grade your requirement points to.

5 min readRead Article →

ISO Polyester Resin vs Vinyl Ester: Where the Line Falls

Vinyl ester is the usual step up from isophthalic polyester for aggressive service. Understand the structural reason vinyl ester resists chemicals and heat better, what it costs in money and process discipline, and how to judge which side of the line your duty sits on.

5 min readRead Article →

How to Specify and Buy ISO Polyester Resin

A practical procurement guide for isophthalic polyester resin: the service data that actually determines the grade, the construction decisions that matter more than resin choice, the documents worth requesting, and the questions that avoid a mis-specified vessel.

5 min readRead Article →

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