HMPSA INCORPORATING A PLASTICISER MADE FROM A RENEWABLE RAW MATERIAL

Abstract

1) An HMPSA composition comprising from 20% to 50% of a composition of styrene block copolymers; from 35% to 65% of tackifying resin; and from 7% to 25%, as plasticizer, of a vegetable oil is chosen from sunflower, rapeseed, linseed and soybean oil. 2) A multilayer system comprising: an adhesive layer (A) consisting of the composition 1); a support layer (B) adjacent to the adhesive layer (A); and a nonstick protective layer (C), adjacent to the adhesive layer (A). 2) The use of said system for the manufacture of self-adhesive articles.

Claims

1-15. (canceled)

16. An HMPSA composition (a) comprising, on the basis of the total weight of said composition: from 20% to 50% by weight of a composition (a1) of styrene block copolymers which comprise at least one elastomer block; from 35% to 65% by weight of one or more tackifying resins (a2); and from 7% to 25% by weight of a plasticizer (a3); wherein the plasticizer (a3) comprises a vegetable oil selected from the group consisting of sunflower, rapeseed, linseed and soybean oil, and of which the derived fatty acids comprise a proportion of at least 75% of fatty acids including 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 derived from the vegetable oil.

17. The HMPSA composition (a) as claimed in claim 16, 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 diblock copolymer selected from the group consisting of SI, SIB, SB, SEB and SEP, and from 10% to 70% by weight of at least one triblock 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).

18. The HMPSA composition (a) as claimed in claim 16, wherein the tackifying resin (a2) comprises: (i) rosins of natural origin or modified rosins and derivatives thereof 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 around 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; or (iv) copolymers based on natural terpenes.

19. The HMPSA composition (a) as claimed in claim 16, wherein the tackifying resin (a2) has a softening temperature of between 80° C. and 120° C.

20. The HMPSA composition (a) as claimed in claim 16, wherein it comprises from 7% to 20% by weight of the vegetable oil (a3).

21. The HMPSA composition (a) as claimed in claim 16, wherein its viscosity, measured by a Brookfield® RVT viscometer at 163° C., is between 4 and 50 Pa.Math.s.

22. A multilayer system comprising: an adhesive layer (A) consisting of the HMPSA composition (a) as defined in claim 16; a support layer (B) adjacent to the adhesive layer (A); and a nonstick protective layer (C), adjacent to the adhesive layer (A).

23. The multilayer system as claimed in claim 22, wherein a thickness of the adhesive layer (A) is strictly greater than 10 μm.

24. The multilayer system as claimed in claim 22, wherein the support layer (B) comprises paper or a film comprising one or more homogeneous layers of a polymer.

25. The multilayer system as claimed in claim 22, wherein the support layer (B) is based on acrylic polymers, on polyethylene (PE), polypropylene (PP), which is oriented, non-oriented or biaxially oriented, polyimide, polyurethane, or polyester.

26. The multilayer system as claimed in claim 22, wherein the protective nonstick layer (C) comprises a silicone-based material.

27. The multilayer system as claimed in claim 22, wherein it is packaged in the form of a winding around a reel.

28. The multilayer system as claimed in claim 27, 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).

29. A self-adhesive article comprising the multilayer system as defined in claim 22.

Description

EXAMPLES A (REFERENCE) AND EXAMPLES 1 TO 3 (ACCORDING TO THE INVENTION)

[0120] The compositions appearing in table 1 below are prepared by simple hot mixing at 180° C. of the ingredients indicated.

[0121] The Brookfield viscosity of these compositions was measured at a temperature of 163° C. The result is indicated in table 2 in mPa.Math.s.

[0122] These compositions were also tested according to the tests described below.

[0123] Adhesive Strength: Peel Test

[0124] The adhesive strength of the compositions is evaluated by the 180° peel test on a plate of a certain substrate, as described in the FINAT test method No. 1, published in the FINAT Technical Handbook, 6.sup.th edition, 2001. FINAT is the International Federation of Self-Adhesive Label Manufacturers and Converters.

[0125] The principle of this test is as follows: A support layer consisting of a 50 μm thick PET film is precoated with the HMPSA in an amount of 20 g/m.sup.2.

[0126] A test specimen in the form of a rectangular strip (25.4 mm×175 mm) is cut from the self-adhesive support thus obtained. This test specimen is fastened to a plate consisting of a certain substrate. The assembly obtained is left at ambient temperature for 20 minutes. It is then introduced into a tensile testing device capable of performing the peeling or detachment of the strip at an angle of 180° and with a separation speed of 300 mm per minute. The device measures the force required to detach the strip under these conditions.

[0127] The result is expressed in N/2.54 cm and is indicated, along with the nature of the substrate of the plate, in table 2.

[0128] Immediate Tack: Loop Tack Test

[0129] The immediate tack of the compositions is evaluated by the loop tack test described in FINAT test method No. 9.

[0130] A support layer consisting of a 50 μm thick PET film is precoated with the HMPSA in an amount of 20 g/m.sup.2 so as to obtain a rectangular strip of 25.4 mm by 175 mm. The two ends of this strip are joined together so as to form a loop, the adhesive layer of which is facing outward. The two joined ends are placed in the movable jaw of a tensile testing device capable of imposing a rate of displacement of 300 mm/minute along a vertical axis with the possibility of back-and-forth motion. The lower part of the loop placed in the vertical position is first brought into contact with a horizontal plate of a certain substrate of 25 mm by 30 mm over a square area measuring about 25 mm per side. Once this contact has been established, the direction of displacement of the jaw is reversed. The immediate tack is the maximum value of the force required for the loop to become completely detached from the substrate plate.

[0131] The result is expressed in N/2.54 cm and is indicated, along with the nature of the substrate of the plate, in table 2.

[0132] The peel and tack results obtained for examples 1 to 3 based on a plasticizer consisting of vegetable oil are generally inferior to those of example A, the plasticizer of which is of petroleum origin. However, these results are perfectly acceptable, with regard to the expected values for self-adhesive articles, and very particularly for self-adhesive labels, as indicated in the description of the present application.

EXAMPLE B (COMPARATIVE)

[0133] The same ingredients as those of example 1 and in the same proportions, with the exception of the replacement of sunflower oil by castor oil, are hot mixed at 180° C.

[0134] The composition obtained is cloudy and inhomogeneous with the presence of solid deposits.

[0135] Such a composition is not suitable as an HMPSA composition.

TABLE-US-00001 TABLE 1 Content in wt % of the ingredient Example Exam- Exam- Exam- Ingredient A (ref.) ple 1 ple 2 ple 3 (a1) Europrène ® Sol T 4.5 4.5 4.5 — 166 Kraton ® D1183 PT 3 3 3 — Solprene ® 1205 26.6 26.6 26.6 — Kraton ® D1118 — — — 33.9 (a2) Sylvalite ® RE 34 34 34 37.4 100S Escorez ® 2203LC 11 11 11 13.4 (a3) Nyflex ® 223 17.5 — — — Sunflower oil — 17.5 — — Rapeseed oil — — 17.5 — Linseed oil — — — 14.8 (a4) Irganox ® 1010 1.4 1.4 1.4 0.5 (a5) A-C ® 8 2 2 2 —

TABLE-US-00002 TABLE 2 Results Example Exam- Exam- Exam- Measurement and tests A (ref.) ple 1 ple 2 ple 3 Brookfield Viscosity at 13250 14000 13650 8900 163° C. (in mPa .Math. s) Peel on stainless steel 15.4 5.6 8.3 17.6 (N/2.54 cm) Peel on HDPE (N/2.54 15.3 5.4 7.5 7.8 cm) Peel on PP (N/2.54 cm) 15.7 5.8 7.6 19.0 Peel on Fipago 10.1 3.4 3.3 4.6 cardboard (N/2.54 cm) Loop tack on glass 32.2 15.7 17.9 25.2 Loop tack on HDPE 22.2 15.6 17.5 15.3 (N/2.54 cm) Loop tack on PP 29.2 16.1 17.4 16.0 (N/2.54 cm) Loop tack on Fipago 8.4 5.9 5.9 8.5 cardboard (N/2.54 cm)