Blended Polyether & Polyester System

Tailor made formulated Polyol systems are manufactured by using majority of the basic polyurethane raw materials. Shakun Industries expertise lies in manufacturing -ready to use- systems according to specific requirements.

A range of polyethers is manufactured using various starters such as sucrose, sorbitol, glycols, pentaerythritol, ethylene diamine, triethylamine and their mixtures. These polyether polyols are marketed under the brand name of Shakun Polyol R100. These are short chain polyethers being used in rigid polyurethane foam formulations.

Polyether polyols' major use is in polyurethane foams. Rigid foam's largest consumer is the construction industry where it is mostly used for insulation. Rigid foam is also used in commercial Refrigeration and packaging. Smaller uses for polyether polyols include Sandwich Panels, Telecommunication shelters, Pipes and chemical storage tanks, Roof spray, Thermoware, Electric heaters, Elastomers, Adhesives and sealants, Surface coatings and Polyurethane fibres.

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Polyester Polyol

A wide range of aliphatic as well as aromatic polyester polyols are manufactured mainly from dibasic acids and diols for varied polyurethane applications. This class of polyols is marketed under the brand names Shakun Polyol. Even while a large selection is available from our standard grades of polyester polyols, Shakun Industries takes pride in taking up development and production of polyesters as per a customer specification.

In comparison with PU based polyether polyols, the PU based polyesters are more resistant to oil, grease, solvents and oxidation. They possess better properties related to: tension and tear strength, flex fatigue, abrasion, adhesion and dimensional stability. On the other hand PU based esters are more sensitive to hydrolysis and microbiological attack. The high mechanical properties of PU based polyester can be explained by the greater compatibility between polar polyester flexible segments and polar rigid segments, causing a slower phase separation resulting in better distributed small crystalline rigid blocks.


Methylene diphenyl diisocyanate, most often abbreviated as MDI, is an aromatic diisocyanate. It exists in three isomers, 2,2-MDI, 2,4-MDI, and 4,4-MDI, however, the 4,4 isomer is most widely used. This isomer is also known as Pure MDI. MDI reacts with polyols in the manufacture of polyurethane.

The major application of 4,4-MDI is the production of rigid polyurethane. Typically, one tonne of polyurethane foam needs 0.616 tonne of MDI and 0.386 tonne of polyol, with 0.054 tonne pentane as a blowing agent. These rigid polyurethane foams are good thermal insulators and used in nearly all freezers and refrigerators worldwide, as well as buildings. Typical polyols used are polyethylene adipate (a polyester) and poly(tetramethylene ether) glycol (a polyether).
4,4-MDI is also used as an industrial strength adhesive, which is available to end consumers as various high-strength bottled glue preparations.