Laropal A 81, which is manufactured by BASF, is a condensation product of urea and aliphatic aldehydes. This low molecular weight resin comes in the form of small pale color pellets. It has a glass transition temperature (Tg) of 57 °C. Its very pale color and good pigment wetting are two properties that make Laropal A81 particularly suitable for producing all-purpose pigment preparations. The low viscosity of its solutions enable high-pigment content pastes to be produced.
This pale, yellowing-resistant aldehyde resin is soluble in almost all paint solvents and compatible with practically all coatings materials. Its main uses are combination with other resin binders and the production of all-purpose pigment paste.
|Property ||Unit ||Amount |
|Softening range (DIN 53180) ||°C ||80–95 |
|Iodine color (DIN 6162) || ||max. 3 |
|Acid value (ISO 3682, DIN 53402) ||mg KOH/g ||max. 3 |
|Density @ 20 °C (ISO 2811, DIN 53217) ||g/cm3 ||approx. 1.11 |
|Hydroxyl value (ISO 4629) ||mg KOH/g ||approx. 40 |
|Saponification value (ISO 3681, DIN 53401) ||mg KOH/g ||approx. 50 |
|Glass transition temperature Tg (DSC) ||°C ||approx. 57 |
Occasional slight fluctuations in color are unavoidable, but do not affect the product’s performance characteristics.
Laropal A 81 is soluble in all common paint solvents but insoluble in water. Its solubility/diluent tolerance in aliphatic solvents such as mineral spirit is limited. Such solutions tend to separate, particularly at temperatures below 15 °C, but can be stabilized by the addition of 2–5% of an aromatic solvent (eg, Solvesso® 100*).
Laropal A 81 is compatible with many coatings materials including:
• alkyd resins
• cellulose nitrate
• cellulose acetobutyrate
• vinyl chloride copolymers
• chlorinated rubber
• melamine-formaldehyde resins
• aromatic and aliphatic epoxy resins
• hydrocarbon resins
• phthalate plasticizers
Laropal A 81’s excellent solubility and compatibility enable it to be used in many types of paints. t can be used to improve gloss, hardness, body, adhesion and yellowing resistance, depending on the coating’s intended application.
A very pale color and good pigment wetting are two properties that make Laropal A 81 particularly suitable for producing all-purpose pigment preparations. The low viscosity of its solutions enable high-pigment-content pastes to be produced.
Since it has good heat resistance, Laropal A 81 is also used for baking finishes, particularly since it does not cause any odors or discoloration of the resin.