Elastomeric compositions providing improved wet grip
View Patent ↗The disclosure relates to elastomeric compositions having improved soft touch feel to skin, and in particular grip, especially during wet/humid conditions. In one embodiment, the compositions are part of a composite system, wherein the compositions are connected, for example bonded, molded, over-molded or co-extruded to a substrate, such as a thermoplastic, wood, glass or metal. The elastomeric composition comprises: (a) one or more copolymers present in an amount of 10 wt. % to 90 wt. %, selected from styrenic block copolymers and isoprene polymers; (b) one or more resins an amount of 2 wt. % to 20 wt. %; and optionally (c) at least one softener, filler, antioxidant or the like present in an amount up to 80 wt. %. The resin is selected from coumarone-indene resin, petroleum hydrocarbon resin, terpene based polymers, styrene-alpha-methyl-styrene resins, rosin derived resins, and mixtures thereof.
1. An elastomeric composition comprising:
a) from 3 to 50 wt. % of a resin selected from the group consisting of a petroleum hydrocarbon resin, terpene based resins, styrene-alpha-methyl-styrene resins, and copolymers and/or mixtures thereof;
b) a first polymer in an amount of 40-95 wt % based on the total weight of the elastomeric composition, the first polymer selected from the group consisting of:
i) a selectively hydrogenated block copolymer having a general configuration A-B-A, (A-B)n, (A-B-A)n, (A-B-A)nX, (A-B)nX or mixtures thereof,
wherein n is an integer from 2 to 30, and X is a coupling agent residue, and
wherein prior to hydrogenation,
A is a polymer block of one or more mono alkenyl arenes, having a number average molecular weight between 3,000 and 60,000; and
B is a controlled distribution copolymer block of at least one conjugated diene and at least one mono alkenyl arene, having a number average molecular weight of 30,000 to 300,000;
ii) a selectively hydrogenated block copolymer having the general configuration S-E-S, (S-E1) n , (S-E1) n S, (S-E1) n X or mixtures thereof,
wherein n has a value of 2 to 6, and X is a coupling agent residue, and
wherein prior to hydrogenation,
S is a polystyrene block,
E is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a number average molecular weight of from 20,000 to 220,000, and
E1 is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a number average molecular weight of from 20,000 to 220,000;
iii) a homopolymer of isoprene, or a copolymer of isoprene and another conjugated diene and/or an olefinically unsaturated monomer, wherein the copolymer can be of random, tapered, or block structure;
and combinations thereof;
c) a second polymer in an amount of 5-55 wt %, wherein the second polymer is selected from the group of a styrene isoprene styrene (SIS), a styrene-ethylene-butadiene-styrene (SEBS), and combinations thereof, and wherein the second polymer is different from the first polymer;
d) optionally, at least one of a softener, a plasticizer, an antioxidant, a stabilizer, a colorant, and a filler, in an amount up to 80 wt. %; and
e) 0.03-25 wt % of a curing agent, said curing agent comprising a peroxide;
wherein the composition has a static coefficient of friction in wet state of at least 1.2 and a kinetic coefficient of friction in wet state of 1.2.
2. The elastomeric composition of claim 1 , wherein
the first polymer is a homopolymer of isoprene, or a copolymer of isoprene and another conjugated diene and/or an olefinically unsaturated monomer, wherein the copolymer can be of random, tapered, or block structure,
the curing agent further comprises x) sulphur or, sulfur-containing compounds; and y) a co-agent selected from the group consisting of monofunctional-, difunctional- and trifunctional methacrylic monomers; and
wherein the composition is cured at a temperature between 135° C.-185° C. for at least 5 minutes.
3. The elastomeric composition of claim 1 , wherein the composition has a static coefficient of friction in a wet state of at least 1.6 and a kinetic coefficient of friction in wet state of at least 1.6.
4. The elastomeric composition of claim 1 , wherein
the first polymer is a selectively hydrogenated block copolymer having a general configuration A-B-A, (A-B)n, (A-B-A)n, (A-B-A)nX, (A-B)nX or mixtures thereof,
wherein n is an integer from 2 to 30, X is a coupling agent residue, and
wherein prior to hydrogenation,
B is a controlled distribution copolymer block of at least one conjugated diene and at least one mono alkenyl arene, having a number average molecular weight of 30,000 to 300,000; and
each block A is a polymer block of one or more mono alkenyl arenes having a number average molecular weight between 3,000 and 60,000.
5. The elastomeric composition of claim 1 , wherein
the first polymer is a selectively hydrogenated block copolymer having a general configuration S-E-S, (S-E1) n , (S-E1) n S, (S-E1) n X or mixtures thereof,
wherein n has a value of 2 to 6 and X is a coupling agent residue, and
wherein prior to hydrogenation,
S is a polystyrene block,
E is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a number average molecular weight of from 20,000 to 220,000, and
E1 is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a number average molecular weight of from 20,000 to 220,000.
6. The elastomeric composition of claim 1 , wherein the first polymer is a homopolymer of isoprene, or a copolymer of isoprene and another conjugated diene and/or olefinically unsaturated monomer, wherein the copolymer can be of random, tapered, or block structure.
7. The elastomeric composition of claim 2 , wherein the co-agent is selected from the group consisting of ethylene glycol dimethacrylate (EGDMA), diethylene glycol dimethacrylate (DEGDMA), triethylene glycol dimethacrylate (TiEGDMA), 1,3-butylene glycol dimethacrylate (BGDMA), trimethylolpropane trimethacrylate (TMPTMA) triallyl isocyanurate, triallyl cyanurate, diethylene glycol diacrylate, neophenylene glycol diacrylate and mixtures thereof.
8. The elastomeric composition of claim 2 , wherein the curing agent is 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, and the co-agent is trimethylolpropane trimethacrylate.
9. The elastomeric composition of claim 6 , wherein the composition has a tensile strength at break, measured according to ASTM D412, of at least 1000 psi.
10. The elastomeric composition of claim 6 , wherein the composition has a 300% modulus, measured according to ASTM D412, of at least 200.
11. The elastomeric composition of claim 1 , wherein the composition has a Type A Durometer hardness, measured at 30 seconds, of at least 35.
12. The elastomeric composition of claim 1 , wherein the resin is a terpene based resin.
13. The elastomeric composition of claim 1 , wherein the resin is a terpene phenol resin having a Tsp ranging from 85° C. to 160° C., and a hydroxyl number ranging from 5 mg KOH/g to 240 mg KOH/g.
14. The elastomeric composition of claim 1 , wherein the resin is a vinyl aromatic resin having a Tsp from 80° C. to 130° C.
15. The elastomeric composition of claim 1 , wherein the resin is selected from the group consisting of terpene polymers, styrene-alpha-methyl-styrene resins, copolymers thereof, and mixtures thereof.
16. The elastomeric composition of claim 1 , wherein the resin is selected from the group consisting of indene resins, aromatic vinyl polymers, and C9 hydrocarbon resins.
17. An article comprising the elastomeric composition of claim 1 .
18. A composite formed by bonding the elastomeric composition of claim 1 with a substrate by any of bonding, molding or using an adhesive, wherein the substrate comprises a polymer.
19. A method for making an elastomeric composition having improved wet grip, the method comprises:
a) mixing:
i) from 3 to 50 wt. % of a resin selected from the group consisting of a petroleum hydrocarbon resin, terpene polymers, styrene-alpha-methyl-styrene resins, and copolymers and/or mixtures thereof;
ii) 40-95 wt % of a homopolymer of isoprene, or a copolymer of isoprene and another conjugated diene and/or an olefinically unsaturated monomer, wherein the copolymer can be of random, tapered, or block structure;
iii) 5-55 wt % of a styrene-butadiene rubber;
iv) a curing agent, said curing agent comprising a peroxide;
v) a co-agent selected from monofunctional-, difunctional- or trifunctional methacrylic monomers; and
vi) optionally, at least one of a softener, a plasticizer, an antioxidant, a stabilizer, a colorant, a filler, and mixtures thereof in an amount of 0 to 80 wt. %;
b) curing the mixture for at least 5 minutes at a temperature between 135° C. and 185° C.;
wherein the composition has a static coefficient of friction in a wet state of at least 1.2 and a kinetic coefficient of friction in wet state of at least 1.2.
20. A method for making an elastomeric composition having improved wet grip, the method comprises mixing:
a) from 3 to 50 wt. % of a resin selected from the group consisting of a petroleum hydrocarbon resin, terpene polymers, styrene-alpha-methyl-styrene resins, and copolymers and/or mixtures thereof;
b) 40-95 wt % of a first polymer selected from the group consisting of:
i) a selectively hydrogenated block copolymer having a general configuration A-B-A, (A-B)n, (A-B-A)n, (A-B-A)nX, (A-B)nX or mixtures thereof,
wherein n is an integer from 2 to 30, and X is a coupling agent residue, and
wherein prior to hydrogenation,
A is a polymer block of one or more mono alkenyl arenes, having a number average molecular weight between 3,000 and 60,000; and
B is a controlled distribution copolymer block of at least one conjugated diene and at least one mono alkenyl arene, having a number average molecular weight of 30,000 to 300,000;
ii) a selectively hydrogenated block copolymer having the general configuration S-E-S, (S-E1) n , (S-E1) n S, (S-E1) n X or mixtures thereof,
wherein n has a value of 2 to 6, and X is a coupling agent residue, and
wherein prior to hydrogenation,
S is a polystyrene block,
E is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a number average molecular weight of from 20,000 to 220,000, and
E1 is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a number average molecular weight of from 20,000 to 220,000;
iii) a homopolymer of isoprene, or a copolymer of isoprene and another conjugated diene and/or an olefinically unsaturated monomer, wherein the copolymer can be of random, tapered, or block structure;
and combinations thereof;
c) 5-55 wt % of a second polymer selected from the group consisting of a styrene isoprene styrene (SIS), a styrene-ethylene-butadiene-styrene (SEBS), and combinations thereof, and wherein the second polymer is different from the first polymer;
d) optionally, at least one of a softener, a plasticizer, an antioxidant, a stabilizer, a colorant, and a filler, in an amount of 0 to 80 wt. %; and
e) 0.03-25 wt % of a curing agent, said curing agent comprising a peroxide;
wherein the composition has a static coefficient of friction in a wet state of at least 1.2 and a kinetic coefficient of friction in wet state of at least 1.2.