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CYMEL® 303 LF Resin

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Function: Crosslinking Agent
Compatible Polymers & Resins: Alkyds, Polyesters, Acrylics, Epoxies (EP)
End Uses: Waterborne Coating
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TypeDocument Name
Technical Data Sheet
CYMEL® 303 LF Resin Technical Data Sheet (ZH)
CYMEL® 303 LF Resin Technical Data Sheet (ZH)
Technical Data Sheet
Technical Data Sheet
CYMEL® 303 LF Resin Technical Data Sheet (EN)
CYMEL® 303 LF Resin Technical Data Sheet (EN)
Technical Data Sheet
Technical Data Sheet
CYMEL® 303 LF Resin Technical Data Sheet (RU)
CYMEL® 303 LF Resin Technical Data Sheet (RU)
Technical Data Sheet

Knowde Enhanced TDS

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Identification & Functionality

CYMEL® 303 LF Resin Features & Benefits

Product Highlights


  • Solvent free
  • Excellent balance of hardness and flexibility
  • Fast catalyzed cure response
  • Excellent stability
  • Low free formaldehyde


  • Coil coatings
  • Can and container coatings
  • Automotive finishes
  • High solids and waterborne coatings
  • General industrial finishes
  • Inks

Applications & Uses


Physical Form
Clear Liquid
Insoluble in
Partially Soluble in
Aliphatic Hydrocarbons
Typical Properties
ValueUnitsTest Method / Conditions
Standard Solvent Tolerancemin. 100--
Colormax. 70APHA-
Non-Volatile Contentmin. 98%wt-
Free Formaldehyde Contentmax. 0.1%-
Dynamic Viscosity (23°C)3000-6000mPa.s-
Solubility & Compatibility


Alcohol Complete
Esters Complete
Ketones Complete
Aromatic hydrocarbons Complete
Aliphatic hydrocarbons Partial
Water Insoluble



Acrylic resins Very good
Alkyd resins Very good
Polyester resins Very good
Epoxy resins Very good

Technical Details & Test Data

Backbone Polymer Selection

CYMEL 303 LF resin contains mainly methoxymethyl functional sites making it a highly effective crosslinker for backbone polymer resins containing hydroxyl, carboxyl, or amide functional groups, such as those found on alkyd, polyester, or acrylic resins. Its high monomer content, and low tendency to self-condense result in films with high flexibility and formability when paired with inherently flexible polymers, such as polyester resins. The effective equivalent weight of CYMEL 303 LF is typically 130-190 g/eq, however, its optimum loading should be determined experimentally for each formulation with consideration of the performance properties to be optimized.


Because of its high extent of alkylation, CYMEL 303 LF resin responds best to sulfonic acid catalysts, like CYCAT® 4040 catalyst or CYCAT ® 600 catalyst. Generally, 0.5 to 1.0% of CYCAT® 4040 catalyst on total resin solids of the formulation is sufficient to provide good cure at normal baking schedules (15-20 minutes at 120-150°C) in solvent-borne systems. Water-borne systems generally require temperatures of 150°C or higher to effect cure. Higher concentrations of catalyst might be necessary if there are basic pigments or additives present in the formulation.



The stability of formulated systems containing CYMEL 303 LF resin can be enhanced by the addition of primary alcohols, amines or a combination of these. Low molecular weight primary alcohols, such as ethanol and n-butanol, are most effective. Recommended amines are DMEA or 2-AMP at a concentration of 0.5- 1.0% on total resin solids. Package stability can also be enhanced by the use of a blocked acid catalyst such as CYCAT 4045 catalyst. For waterborne systems, pH should be adjusted to 7.5-8.5 to achieve optimum stability.


CYMEL 303 LF resin has a shelf life of 1800 days from the date of manufacture when stored at temperatures below 32°C. Although low temperatures are not detrimental to stability, its viscosity will increase, possibly making the resin difficult to pump or pour. The viscosity will reduce again on warming, but care should be taken to avoid excessive local heat, as this can cause an irreversible increase in viscosity.

WARNING: CYMEL 303 LF resin may turn hazy when cold due to crystallization of hexamethoxymethylmelamine (HMMM). Warming will return the product to normal with no adverse impact on performance.

Storage & Handling

Shelf Life
1800 Days
CYMEL® 303 LF Resin