Premium diol for high performance polyester, unsaturated polyester and polyurethane resins

Synthomer’s SYNOXOL™ BEPD (butyl ethyl propanediol) is a high performance aliphatic diol, with primary OH groups, for the synthesis of saturated and unsaturated polyesters. It is also an excellent choice for use as a chain extender or as part of polyester polyols in polyurethane systems.


Its branched structure increases hydrophobicity (water resistance), improves hydrolytic resistance and offers a reduction in crystallinity in the saturated polyester resin; whilst delivering harder but flexible mechanical performance. SYNOXOL™ BEPD also increases solvent compatibility and gives strong UV resistance for outdoor exposed  applications.


Delivering an effective formulation design for high molecular weight, low viscosity unsaturated polyester resins (UPRs), SYNOXOL™ BEPD reduces VOC and styrene content with no adverse impact on outdoor durability or mechanical performance. In fact, it reduces water absorption and shrinkage upon cure, allowing the use of cost effective glycol blends as part of UPR formulation designs for demanding applications


SYNOXOL™ BEPD can be used both in the polyester polyol and as a chain extender in polyurethane systems. The use of SYNOXOL™ BEPD improves hydrolysis resistance and abrasion resistance. It’s branched structure reduces crystallinity, thus increasing transparency. When used within a polyurethane dispersion, it provides good film formation at low MFFT (minimum film forming temperature) leading to excellent aesthetics and high gloss finishes.

Key application areas:


Saturated Polyester Applications

Unsaturated Polyester Applications

Polyurethane Applications

(PES Polyol, Chain Extender, PUD)

Coil & Extrusion Coatings


Automotive, Wood & Industrial Coatings

Can Coatings

Engineered stone/marble

RHM, 2K Solvent /
Waterbased Adhesives

Powder Coatings


Artificial Leather


Outdoor fabric & Sportswear


TPU plastic & components

Key Features:

Polyester Coil Coatings

Polyester Powder Coatings

UPR Gelcoats & Composites

Polyurethane Applications

Increased hardness

Improved bloom resistance down to 140-160°C cure temp

Reduced viscosity

Higher hydrolysis resistance

Lower VOC & Styrene content

Improved abrasion resistance

Improved flexibility

Reduced gel time

Lower water absorption

Improved water resistance

Higher UV resistance

Higher UV resistance

Higher flexural strength

Higher transparency

Increased spreading rate (m²/Lt)

Increased reactivity

Lower shrinkage upon cure

Lower MFFT

Improved cost/m²

Reduced energy cost

Improved UV resistance

Higher gloss

Recommended Products

Tradename Chemistry Description
SYNOXOL™ BEPD OTH 2-Butyl-2-Ethyl-1,3-PropanediolWhite crystalline solidDiol containing primary hydroxyl groupsThe product is FDA approvedCAS number: 115-84-4EC (EINECS) number: 204-111-7HS number: 2905 39
SYNOXOL™ BEPD70L OTH BEPD 70L is a mixture of 2-Butyl-2-Ethyl-1,3-Propanediol (BEPD), Neopentyl Glycol and waterClear and colourless liquid at room temperatureDiol containing primary hydroxyl groupsCAS number: 115-84-4, 126-30-7, 7732-18-5EC (EINECS) number: 204-111-7, 204-781-0, 231-791-2 HS number: 3824 99

Discover how SYNOXOL™ BEPD and SYNOXOL™ BEPD70L can add value to your high performance polyester and polyurethane resins

Contact our technical specialists and customer services team for further information.


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