Web material with an ultrathin coating varnish allowing rapid sustained spreading and/or very rapid, sustained transport of fluids

1. Material in web form comprising a carrier material coated on one or both sides with a coating solution consisting essentially of at least one anionic surfactant based on a sulphosuccinic ester salt, the coating solution forms an ultrathin coating varnish having a dried coating application weight of 5 to 52 mg/m 2 , wherein the sulphosuccinic ester salt has the following chemical structure:

R′OOC—CH 2 —CH(SO 3 − )—COOR″M +

wherein,

M + =Na + , and

R′ and R″=an alkyl chain.

2. Web material according to claim 1 , wherein the ultrathin coating varnish possesses the following properties:

a surface tension of at least 65 mN/m

a contact angle with water of less than 30° and/or

an areal spread with 0.5 ml of water of at least 10 cm 2 .

3. Web material according to claim 2 , wherein the areal spread is 0.5 ml of water on the ultrathin coating varnish after storage at 40° C. for 10 weeks or at 70° C. for 10 weeks is at least 85% of the original value prior to storage.

4. Web material according to claim 1 , wherein the coating solution is applied over the whole area.

5. Web material according to claim 1 , wherein the dried coating application of the ultrathin coating varnish is 15-30 mg/m 2 .

6. Web material according to claim 1 , wherein the at least one anionic surfactant consists essentially of sodium bis-2-ethylhexyl sulphosuccinate.

7. Web material according to claim 1 , wherein the carrier material is composed of a polyester film having a thickness of 12 to 350 μm.

8. Web material according to claim 1 , wherein the transport rate of an aqueous test fluid (deionized water and 0.1% by weight of methyl blue) in a channel (75 μm×1 mm) in which the ultrathin coating varnish forms one wall of the channel, is at least 20 mm/s.

9. Web material according to claim 1 , wherein the transport rate of an aqueous test fluid (deionized water and 0.1% by weight of methyl blue) in a channel (75 μm×1 mm), in which the ultrathin coating varnish forms one wall of the channel, after storage at 40° C. for 10 weeks or at 70° C. for 6 weeks is at least 20 mm/s.

10. A diagnostic strip, biosensor, point-of-care device or microfluidic device used to analyse biological fluids, wherein said diagnostic strip, biosensor, point-of-care device or microfluidic device comprises web material according to claim 1 .

11. Process for producing a web material according to claim 1 , comprising applying a coating solution comprising a solvent consisting essentially of in solution at least one anionic surfactant based on a sulphosuccinic ester salt, the solids content in the coating solution being less than 2% by weight, to a carrier material and the carrier material with the coating solution is dried so that, after drying, a coating application in the form of an ultrathin coating varnish of 5 to 52 mg/m 2 is produced, wherein the sulphosuccinic ester salt has the following chemical structure:

R′OOC—CH 2 —CH(SO 3 − )—COOR″M +

wherein,

M + =Na + , and

R′ and R″=an alkyl chain.

12. Process according to claim 11 , wherein the carrier material is coated on both sides with the coating solution and then dried.

13. Process according to claim 11 , wherein the coating of the ultrathin coating varnish takes place with an alcoholic solution that is subsequently dried.

14. Process according to claim 13 , wherein the alcoholic solution comprises exclusively the anionic surfactant based on a sulphosuccinic ester salt without further additives.

15. Web material according to claim 1 , wherein the alkyl chain is selected from the group consisting of butyl, hexyl and 2-ethylhexyl.

16. Process according to claim 11 , wherein the alkyl chain is selected from the group consisting of butyl, hexyl and 2-ethylhexyl.