HMPSA incorporating a plasticiser made from a renewable raw material

1. An HMPSA composition which comprises, on the basis of the total weight of said composition:

from 31%-45% by weight of a composition (a1) of styrene block copolymers which comprise at least one elastomer block;

from 40%-55% by weight of one or more tackifying resins (a2); and

from 10%-19% by weight of a plasticizer (a3);

wherein the plasticizer (a3) has a composition (a3) comprising a stand oil (a3-1) of a vegetable oil.

2. The HMPSA composition as claimed in claim 1 , wherein the composition (a1) of styrene block copolymers comprises, on the basis of its total weight:

from 30% to 90% by weight of at least one copolymer selected from the group consisting of SI, SIB, SB, SEB and SEP, and

from 10% to 70% by weight of at least one copolymer selected from the group consisting of SIS, SIBS, SBS, SEBS and SEPS;

wherein the total content of styrene units of said composition (a1) ranges from 10% to 40% by weight on the basis of the total weight of (a1).

3. The HMPSA composition as claimed in claim 1 , wherein the one or more tackifying resins (a2) is selected from the group consisting of:

(i) rosins of natural origin or modified rosins and derivatives of both rosins of natural origin and modified rosins which are hydrogenated, dehydrogenated, dimerized, polymerized or esterified with monoalcohols or polyols;

(ii) resins obtained by hydrogenation, polymerization or copolymerization (with an aromatic hydrocarbon) of mixtures of unsaturated hydrocarbons having 5, 9 or 10 carbon atoms derived from petroleum cuts;

(iii) terpene resins resulting from the polymerization of terpene hydrocarbons in the presence of Friedel-Crafts catalysts, which are optionally modified by the action of phenols; and

(iv) copolymers based on natural terpenes.

4. The HMPSA composition as claimed in claim 1 , wherein the vegetable oil stand oil (a3-1) is obtained by a process comprising a step of heating said vegetable oil in the absence of dioxygen at a temperature above 200° C.

5. The HMPSA composition as claimed in claim 4 , wherein the stand oil (a3-1) has a Brookfield viscosity, measured at 20° ° C., of greater than or equal to 50 mPa·s.

6. The HMPSA composition as claimed in claim 1 , wherein the stand oil (a3-1) is a stand oil of a vegetable oil, wherein the vegetable oil is a composition of triple esters of fatty acids and glycerol, wherein at least 75% of the fatty acids in the triple esters include from 16 to 22 carbon atoms, said proportion being expressed as a percentage by weight on the basis of the total weight of the fatty acids in the triple esters.

7. The HMPSA composition as claimed in claim 1 , wherein the stand oil (a3-1) is a stand oil of a vegetable oil selected from the group consisting of sunflower, rapeseed, linseed and soybean oil.

8. The HMPSA composition as claimed in claim 1 , wherein the plasticizer composition (a3) consists of the stand oil (a3-1).

9. The HMPSA composition as claimed in claim 1 , wherein the plasticizer composition (a3) comprises, in addition to the stand oil (a3-1), a vegetable oil (a3-2) selected from the group consisting of sunflower, rapeseed, linseed and soybean oil, wherein the vegetable oil is a composition of triple esters of fatty acids and glycerol, wherein at least 75% of fatty acids in the triple esters include from 16 to 22 carbon atoms, said percentage being a percentage by weight expressed on the basis of the total weight of the fatty acids in the triple esters.

10. A multilayer system comprising:

an adhesive layer (A) comprising the HMPSA composition as defined in claim 1 ;

a support layer (B) adjacent to the adhesive layer (A); and

a nonstick protective layer (C), adjacent to the adhesive layer (A).

11. The multilayer system as claimed in claim 10 , wherein a thickness of the adhesive layer (A) is strictly greater than 10 μm.

12. The multilayer system as claimed in claim 10 , wherein the multilayer system is packaged in the form of a winding around a reel.

13. The multilayer system as claimed in claim 12 , wherein the protective nonstick layer (C) comprises a silicone-based material coated on a face of the support layer (B) which is opposite a face in contact with the adhesive layer (A).

14. A self-adhesive article comprising the multilayer system as defined in claim 10 .