Solvent-based coatings, inks and adhesives: which sample form can be sent for analysis

A solvent-based coating, ink or adhesive changes as it is applied and dried. The wet product contains a volatile phase as well as material intended to remain on the surface. A cured or dried film preserves much of the latter but cannot preserve solvent that has evaporated. A separated solids fraction can also differ from the original liquid if preparation selectively loses or enriches ingredients. Before asking for deformulation, decide whether you need to know the incoming liquid, the nonvolatile formulation or the chemistry of the finished film.

For overseas receipt, we do not accept these solvent-based products in liquid form. We can review a cured film or solids fraction instead, subject to the declaration and SDS. The same limit applies to other liquids that are not water-based, such as UV-curable inks, solvent-free liquid resins and lubricating oils: we receive only solids, water-based products and cured samples. Where the product can be cured, a cured sample can be proposed instead. If the same product can be bought or delivered within mainland China, for example by your Chinese supplier, say so in your declaration: no import is involved on that route. The declaration, quotation, payment and acceptance number still come first. This is a change in the sample, not merely a shipping workaround. If the question is the original solvent blend, a cured film is not an adequate proxy. If the question concerns the binder, pigment or retained additive package, a film may be a more relevant object, although it still has its own limits.

A solids fraction is a preparation of the original material, not the original material itself. Its value depends on how it was separated and whether any semi-volatile or soluble ingredients moved with the discarded phase. If you prepare it, record the preparation method and keep the untouched product description in the declaration. Do not label the solids simply as the complete liquid formulation. The resulting estimate describes the analyzed fraction and cannot be multiplied into a full wet recipe without defensible information about the missing phase.

Physical-form review remains necessary even when the label says "solid fraction". We need photographs and an SDS for the actual product, and we may ask for a full component list before acceptance. A mixture that still contains free solvent should not be presumed to meet the cured or solid category. Declare the actual state, including any residual liquid, and wait for our acceptance decision.

We accept overseas industrial samples after declaration review. Use the sample declaration form and read the related guide. Our reports are research-grade analytical reports from a laboratory that is not accredited. They cannot be used for product registration or legal proceedings.