Compositions having reduced tack and articles made thereof
A oil gel composition, consisting essentially of: 65-80 wt. % of a mineral oil, 15-25 wt. % of a hydrogenated styrenic block copolymer (HSBC), 1 to 15 wt. % of glass spheres having an average particle size of at least 15 microns, 1 at least 50 wt. % of a plasticizer selected from mineral oil, a paraffinic oil, an oil-enriched in paraffin, and mixtures thereof, and 0.25-5 wt. % of a tack reducing component selected from the group of steric acid, metal stearates, long chain fatty acids, fatty acid salts, fatty acid esters, amide waxes, ethylene-bis-stearamides, erucamide, polyester modified siloxanes, and mixtures thereof. The oil gel composition has an average peel strength of less than 0.3 lbf/in measured according to ASTM D 1876. Articles formed from the oil gel composition are characterized as being tack-free.
1. An article molded from an oil gel composition consisting essentially of:
10-40 wt. % of a hydrogenated styrenic block copolymer (HSBC), having a general formula of A-B, A-B-A, A-B-A-B, (A-B-A)nX, (A-B)nX, or mixtures thereof, where each A block is a mono alkenyl arene polymer, each B block is a conjugated diene, n is an integer from 2 to 30, and X is a coupling agent residue;
up to 15 wt. % of a filler;
at least 50 wt. % of a plasticizer selected from mineral oil, a paraffinic oil, an oil-enriched in paraffin, and mixtures thereof;
0.25-5 wt. % of a tack reducing component selected from the group of stearic acid, metal stearates, long chain fatty acids, fatty acid salts, fatty acid esters, amide waxes, ethylene-bis-stearamides, erucamide, polyester modified siloxanes, and mixtures thereof, based on the total weight of the oil gel composition;
wherein the article is molded in a process without additional application of an external mold release surface coating or a powder coating to mold surface, and wherein the oil gel composition does not stick to the mold surface; and
wherein the article has an average peel strength of less than 53 N/m (0.3 lbf/in) according to modified ASTM D 1876.
2. The article of claim 1 , wherein the hydrogenated styrenic block copolymer comprises:
a tetra-branched block copolymer (IV) having a styrene equivalent peak molecular weight of 100,000 to 800,000 represented by the general formula (A-B) 4 X;
a tri-branched block copolymer (III) having a styrene equivalent peak molecular weight of from 75,000 to 600,000 represented by the general formula (A-B) 3 X;
a di-branched block copolymer (II) having a styrene equivalent peak molecular weight of from 50,000 to 400,000 represented by the general formula (A-B) 2 X; and
a linear diblock copolymer (I) having a styrene equivalent peak molecular weight of from 25,000 to 200,000 represented by the general formula A-B;
wherein:
A represents a polymer block of a mono alkenyl arene;
B represents a polymer block of a conjugated diene selected from the group consisting essentially of butadiene and mixtures of isoprene and butadiene;
X represents the residue of an alkoxy silane coupling agent having the formula Rx-Si—(OR′)y, where x is 0 or 1, x+y=4, R and R′ are the same or different, R is selected from aryl hydrocarbon radicals, linear alkyl hydrocarbon radicals and branched alkyl hydrocarbon radicals, and R′ is selected from linear and branched alkyl hydrocarbon radicals; and
wherein the relative amounts of copolymers I, II, III and IV are from 0 to 5 weight percent IV, from 0 to 60 weight percent III, from 40 to 95 weight percent II and from 2 to 10 weight percent 1, where the total of I, II, III and IV equals 100 weight percent.
3. The article of claim 1 , wherein the hydrogenated styrenic block copolymer is a styrene-ethylene-butylene-styrene (SEBS) or styrene-ethylene-ethylene-propylene-styrene (SEEPS) block copolymer.
4. The article of claim 1 , wherein the article is formed by any of injection molding, compression molding, rotomolding, thermoforming, casting, extrusion, profile extrusion, or blow molding.
5. The article of claim 1 , wherein the article is any of a mattress, a pillow, a mattress topper, a footwear cushion, an arm pad, a wrist or arm rest, a seating apparatus, a bedding product, upholstery, a pet bed, a medical cushioning foam, a seat cushion, an automotive foam, a sport cushion, a transportation cushion, a headrest, a personal protective equipment, or a toy.
6. The article of claim 1 , wherein the plasticizer is a mineral oil.
7. The article of claim 1 , wherein the tack reducing component is selected from stearic acid, fatty stearate salts, and mixtures thereof, and wherein the oil gel composition has an average peel strength of less than 35 N/m (0.2 lbf/in).
8. The article of claim 1 , wherein the tack reducing component is polycaprolactone-polydimethysiloxane block copolymer.
9. The article of claim 1 , wherein the tack reducing component is a lubricating grease selected from the group of organic fatty acids, esters, amides, and mixtures thereof, and wherein the lubricating grease has a drop melt point of at least 65° C., as defined by ASTM-127.
10. The article of claim 1 , wherein the tack reducing component is selected from ethylene-bis-stearamide, erucamide, or mixtures thereof.
11. A method of forming a molded article, the method comprising:
providing an oil gel composition has an average peel strength of less than 53 N/m (0.3 lbf/in) measured according to ASTM D 1876, the oil gel composition consists essentially of
10-40 wt. % of a hydrogenated styrenic block copolymer (HSBC), having a general formula A-B, A-B-A, A-B-A-B, (A-B-A)nX, (A-B)nX, or mixtures thereof, where each A block is a mono alkenyl arene polymer, each B block is a conjugated diene, n is an integer from 2 to 30, and X is a coupling agent residue;
1 to 15 wt. % of glass spheres having an average particle size of at least 15 microns;
at least 50 wt. % of a plasticizer selected from mineral oil, a paraffinic oil, an oil-enriched in paraffin, and mixtures thereof;
0.25-5 wt. % of a tack reducing component selected from the group of stearic acid, metal stearates, long chain fatty acids, fatty acid salts, fatty acid esters, amide waxes, ethylene-bis-stearamides, erucamide, polyester modified siloxanes, and mixtures thereof, based on the total weight of the oil gel composition;
injecting the oil gel composition into a mold to form the molded article without application of any mold release surface coating or a powder coating to mold surface; and wherein the oil gel composition does not stick to the mold surface.
12. The method of claim 11 , wherein providing the oil gel composition consists essentially of
forming a mixture with 10-40 wt. % of a hydrogenated styrenic block copolymer (HSBC), having a general formula A-B, A-B-A, A-B-A-B, (A-B-A)nX, (A-B)nX, or mixtures thereof, where each A block is a mono alkenyl arene polymer, each B block is a conjugated diene, n is an integer from 2 to 30, and X is a coupling agent residue;
1 to 15 wt. % of glass spheres having an average particle size of at least 15 microns; and
adding to the mixture
the at least 50 wt. % of a plasticizer selected from mineral oil, a paraffinic oil, an oil-enriched in paraffin, and mixtures thereof, and
the 0.25-5 wt. % of a tack reducing component selected from the group of stearic acid, metal stearates, long chain fatty acids, fatty acid salts, fatty acid esters, amide waxes, ethylene-bis-stearamides, erucamide, polyester modified siloxanes, and mixtures thereof, based on the total weight of the oil gel composition.
13. The method of claim 11 , wherein the hydrogenated styrenic block copolymer is a styrene-ethylene-butylene-styrene (SEBS) or styrene-ethylene-ethylene-propylene-styrene (SEEPS) block copolymer.
14. The method of claim 11 , wherein the hydrogenated styrenic block copolymer comprises:
a tetra-branched block copolymer (IV) having a styrene equivalent peak molecular weight of 100,000 to 800,000 represented by the general formula (A-B) 4 X;
a tri-branched block copolymer (III) having a styrene equivalent peak molecular weight of from 75,000 to 600,000 represented by the general formula (A-B) 3 X;
a di-branched block copolymer (II) having a styrene equivalent peak molecular weight of from 50,000 to 400,000 represented by the general formula (A-B) 2 X; and
a linear diblock copolymer (I) having a styrene equivalent peak molecular weight of from 25,000 to 200,000 represented by the general formula A-B;
wherein:
A represents a polymer block of a mono alkenyl arene;
B represents a polymer block of a conjugated diene selected from the group consisting essentially of butadiene and mixtures of isoprene and butadiene;
X represents the residue of an alkoxy silane coupling agent having the formula Rx-Si—(OR′)y, where x is 0 or 1, x+y=4, R and R′ are the same or different, R is selected from aryl hydrocarbon radicals, linear alkyl hydrocarbon radicals and branched alkyl hydrocarbon radicals, and R′ is selected from linear and branched alkyl hydrocarbon radicals; and
wherein the relative amounts of copolymers I, II, III and IV are from 0 to 5 weight percent IV, from 0 to 60 weight percent III, from 40 to 95 weight percent II and from 2 to 10 weight percent 1 , where the total of I, II, III and IV equals 100 weight percent.
15. The method of claim 11 , wherein the molding is any of injection molding, compression molding, rotomolding, or thermoforming.
16. The method of claim 11 , wherein the tack reducing component is polycaprolactone-polydimethysiloxane block copolymer.
17. The method of claim 11 , wherein the tack reducing component is selected from stearic acid, fatty stearate salts, or mixtures thereof.
18. An article formed by the method of claim 11 .