Copolyester/controlled distribution styrenic block copolymer blends and methods of making and using same
A composition comprising (i) a controlled distribution styrenic block copolymer and (ii) a thermoplastic copolyester wherein the composition has a Shore A hardness of from about 50 to about 90 and a melt flow rate of from about 15 g/10 min. to about 50 g/10 min. as determined in accordance with ASTM D 1238.
1. A composition consisting essentially of (i) a controlled distribution styrenic block copolymer and (ii) a thermoplastic copolyester wherein the composition has a Shore A hardness of from about 50 to about 90 and a melt flow rate of from about 15 g/10 min. to about 50 g/10 min. as determined in accordance with ASTM D 1238;
wherein the thermoplastic copolyester comprises at least one segment containing butylene terephthalate, tetramethylene terephthalate, or ethylene terephthalate units and at least one segment containing poly(alkylene oxide) glycols having a total of about 3 to about 12 carbon atoms;
wherein the controlled distribution styrenic block copolymer has a melt flow rate of greater than 30 g/10 min. as determined in accordance with ASTM 1238 at 230° C. and 2.16 kg.
2. The composition of claim 1 wherein composition comprises about 50 to about 79 wt. % of the thermoplastic copolyester and about 21 to about 50 wt. % of the controlled distribution styrenic block copolymer based on the total weight of the composition; and wherein the controlled distribution styrenic block copolymer has a first block comprising a styrenic polymer, a midblock comprising a terpolymer, and an end block comprising a styrenic polymer.
3. The composition of claim 1 wherein the controlled distribution styrenic block copolymer comprises styrene, alpha-methylstyrene, para-methylstyrene, vinyl toluene, vinylnaphthalene, para-butyl styrene or combinations thereof.
4. The composition of claim 2 wherein the terpolymer comprises styrene and a conjugated diene.
5. The composition of claim 4 wherein the conjugated diene comprises 1,3-butadiene, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, 1-phenyl-1,3-butadiene, or combinations thereof.
6. The composition of claim 2 wherein the midblock comprises an ethylene/butadiene/styrene terpolymer.
7. The composition of claim 1 wherein the controlled distribution styrenic block copolymer has a polystyrene content of from about 20% to about 60%.
8. The composition of claim 1 wherein the controlled distribution styrenic block copolymer has a melt flow rate of from about 40 g/10 min. to about 100 g/10 min. as determined in accordance with ASTM 1238 at 230° C. and 2.16 kg.
9. The composition of claim 1 wherein the controlled distribution styrenic block copolymer has a Shore A hardness of from about 20 to about 90.
10. The composition of claim 1 wherein the copolyester has one or both of a Shore D hardness of from about 22 to about 60 or a Shore A hardness of about 76 to about 97.
11. The composition of claim 1 wherein the thermoplastic copolyester comprises the butylene terephthalate.
12. The composition of claim 1 wherein the composition excludes a plasticizer, a flow promoter or combinations thereof.
13. The composition of claim 12 wherein the plasticizer or flow promoter comprises mineral-based oil, treated distilled aromatic extract (TDAE), mild extract solvate (MES), residual aromatic extract (RAE), treated aromatic extract (TAE), naphthenic oil, white oil, black naphthenic oil, vegetable oils, sunflower oil, carnauba oil, linseed oil, rape seed oil, derivatives thereof, or combinations thereof.
14. The composition of claim 1 which when formed into a test specimen has a tear strength of from about 25 kN/m to about 145 kN/m as determined in accordance with ASTM D624.
15. The composition of claim 1 which when formed into a test specimen has a static coefficient of friction when sliding over itself of from about 0.15 to about 0.8 as determined in accordance with ASTM D1894.
16. The composition of claim 1 which when formed into a test specimen has an elongation at break of from about 200% to about 1300% as determined in accordance with DIN 53504.
17. The composition of claim 1 which when formed into a test specimen has an elongation at break of greater than about 200% as determined in accordance with DIN 53504.
18. The composition of claim 1 which when formed into a test specimen has a peel adhesion of from about 25 N/25 mm to about 300 N/25 mm as determined in accordance with ISO 8510-2.
19. An overmolding prepared from the composition of claim 1 .
20. A composition comprising:
(i) about 21 to about 50 wt. % based on the total weight of the composition of a controlled distribution styrenic block copolymer having a first block comprising a styrenic polymer, a midblock comprising a terpolymer, and an end block comprising a styrenic polymer; wherein the controlled distribution styrenic block copolymer has a polystyrene content of from about 20% to about 60%; wherein the controlled distribution styrenic block copolymer has a melt flow rate of from about 1 g/10 min. to about 100 g/10 min. as determined in accordance with ASTM 1238 at 230° C. and 2.16 kg and a Shore A hardness of from about 20 to about 90; and
(ii) about 50 to about 79 wt. % based on the total weight of the composition a thermoplastic copolyester comprising at least one segment containing butylene terephthalate, tetramethylene terephthalate, or ethylene terephthalate units and at least one segment containing poly(alkylene oxide) glycols having a total of about 3 to about 12 carbon atoms; wherein the copolyester has a melt flow rate of 9 to 39 g/10 min;
wherein the composition excludes a plasticizer, a flow promoter, or combinations thereof and has a melt flow rate of from about 15 g/10 min. to about 50 g/10 min. as determined in accordance with ASTM D 1238;
wherein the composition has a Shore A hardness of from about 50 to about 90.