Surfactant, dispersion and adhesive composition
The invention relates to a surfactant comprising a grafted rosin ester which is a rosin ester grafted with a capped polyalkylene glycol, wherein the capped polyalkylene glycol is a polyalkylene glycol capped by an alkyl ether and an aqueous dispersion consisting of an aqueous phase and resin particles dispersed in the aqueous phase, wherein the dispersion comprises the surfactant according to the invention.
1. A surfactant, comprising:
a grafted rosin ester which is a rosin ester grafted with a capped polyethylene glycol, wherein the capped polyethylene glycol is a end-capped by an alkyl ether, wherein the capped polyethylene glycol has a Mw of 2000 to 8000, and wherein the alkyl ether has 1 to 4 carbon atoms.
2. The surfactant according to claim 1 , wherein the molar ratio between the rosin ester and the capped polyethylene glycol is 0.05:1 to 1:1.
3. A process for the preparation of the surfactant according to claim 1 , comprising the steps of: (2a) grafting the rosin esterwith an unsaturated carboxylic acid or anhydride, and (3a) esterifying the product obtained by step (2a) with the capped polvethylene glycol to obtain the grafted rosin ester; or (2b) esterifying an unsaturated carboxylic acid or anhydride with the capped polyethylene glycol, and (3b) grafting the rosin ester with the product of step (2b) to obtain the grafted rosin ester.
4. The process according to claim 3 , further comprising the step of: (1) esterifying a rosin with an alcohol.
5. The process according to claim 3 , wherein the unsaturated carboxylic acid or anhydride is selected from the group consisting of maleic acid, maleic anhydride, fumaric acid or mixtures thereof.
6. An aqueous dispersion comprising an aqueous phase and resin particles dispersed in the aqueous phase, wherein the dispersion comprises the surfactant according to claim 1 .
7. The aqueous dispersion according to claim 6 , wherein the resin particles are made of a resinous material and the surfactant, wherein the resinous material is selected from the group consisting of a hydrocarbon resin, an alkyd resin, a polyamide resin, a rosin resin and mixtures thereof.
8. The aqueous dispersion according to claim 6 , wherein the dispersion has a solids content of at least 61 wt. %.
9. The aqueous dispersion according to claim 6 , wherein the dispersion has a Brookfield viscosity measured using spindle 3 and operated at 50 rpm at 20° C. of at most 2000 mPa-s.
10. The aqueous dispersion according to claim 6 , further comprising an anionic emulsifier, wherein the amount of the anionic emulsifier is with respect to the resinous material is at most 3.0 wt. %, at most 2.5 wt. %, at most 2.0 wt. %, at most 1.5 wt. %, at most 1.0 wt. % or at most 0.5 wt. %.
11. The aqueous dispersion according to claim 6 , wherein the particles have a multimodal particle size distribution.
12. A process for the preparation of the aqueous dispersion according to claim 6 , comprising the step of mixing a melt of the resinous material, the surfactant and water.
13. An adhesive composition comprising a polymer latex and the aqueous dispersion according to claim 6 .
14. An article obtained by or obtainable by applying the adhesive composition according to claim 13 on a carrier and drying the adhesive composition.