Crosslinkable and foamable composition, foam obtained by the same, composition for foaming and use thereof
A crosslinkable and foamable composition is provided, which comprises a hydrogenated styrenic diblock copolymer, a free radical initiator and a foaming agent, wherein the hydrogenated styrenic diblock copolymer comprises: a first block comprising a conjugated diene monomer unit; and a second block comprising a styrene unit, wherein the hydrogenated styrenic diblock copolymer comprises 10 to 60 wt % of the styrene unit, 50 mol % or more of the conjugated diene monomer unit is hydrogenated, and the hydrogenated styrenic diblock copolymer has a weight average molecular weight of 30000 to 200000. In addition, a foam obtained by crosslinking and foaming the aforesaid crosslinkable and foamable composition is also provided.
1 . A crosslinkable and foamable composition, comprising a hydrogenated styrenic diblock copolymer, a free radical initiator, and a foaming agent, wherein the hydrogenated styrenic diblock copolymer comprises:
a first block comprising a conjugated diene monomer unit; and
a second block comprising a styrene unit,
wherein the hydrogenated styrenic diblock copolymer comprises 10 to 60 wt % of the styrene unit, 50 mol % or more of the conjugated diene monomer unit is hydrogenated, and the hydrogenated styrenic diblock copolymer has a weight average molecular weight of 30000 to 200000.
2 . The crosslinkable and foamable composition of claim 1 , wherein the first block is a polymer block of a butadiene unit, an isoprene unit, or a mixture thereof, and the second block is a polymer block of the styrene unit.
3 . The crosslinkable and foamable composition of claim 1 , wherein the first block is a polymer block of a butadiene unit, an isoprene unit, or a mixture thereof, and the second block is a polymer block of the styrene unit and a conjugated diene monomer unit, wherein the conjugated diene monomer unit is a butadiene unit, an isoprene unit, or a mixture thereof, and a content of the conjugated diene monomer unit in the second block is less than or equal to 15 wt % based on a total weight of the second block.
4 . The crosslinkable and foamable composition of claim 1 , wherein the first block is a polymer block of a butadiene unit, and the second block is a polymer block of the styrene unit.
5 . The crosslinkable and foamable composition of claim 1 , wherein the first block is a polymer block of a butadiene unit, and the second block is a polymer block of the styrene unit and a butadiene unit, wherein a content of the butadiene unit in the second block is less than or equal to 15 wt % based on a total weight of the second block.
6 . The crosslinkable and foamable composition of claim 2 , wherein a 1,2-vinyl bond content in the butadiene unit is in a range of 5 to 60 mol % prior to hydrogenation.
7 . The crosslinkable and foamable composition of claim 3 , wherein a 1,2-vinyl bond content in the butadiene unit is in a range of 5 to 60 mol % prior to hydrogenation.
8 . The crosslinkable and foamable composition of claim 4 , wherein a 1,2-vinyl bond content in the butadiene unit is in a range of 5 to 60 mol % prior to hydrogenation.
9 . The crosslinkable and foamable composition of claim 5 , wherein a 1,2-vinyl bond content in the butadiene unit is in a range of 5 to 60 mol % prior to hydrogenation.
10 . The crosslinkable and foamable composition of claim 2 , wherein a 3,4-vinyl bond content in the isoprene unit is in the range of 5 to 60 mol % prior to hydrogenation.
11 . The crosslinkable and foamable composition of claim 3 , wherein a 3,4-vinyl bond content in the isoprene unit is in the range of 5 to 60 mol % prior to hydrogenation.
12 . The crosslinkable and foamable composition of claim 1 , wherein 60 to 95 mol % of the conjugated diene monomer unit is hydrogenated after hydrogenation.
13 . The crosslinkable and foamable composition of claim 1 , wherein the free radical initiator is an organic peroxide, wherein the organic peroxide is selected from the group consisting of dicumyl peroxide, bis(1-(tert-butylperoxy)-1-methylethyl)-benzene, and a combination thereof.
14 . The crosslinkable and foamable composition of claim 1 , wherein the foaming agent is a chemical foaming agent, wherein the chemical foaming agent is azodicarbonamide.
15 . The crosslinkable and foamable composition of claim 1 , further comprising a crosslinking co-agent.
16 . A crosslinkable and foamable composition of claim 1 , further comprising an ethylene copolymer, wherein a weight ratio of the ethylene copolymer to the hydrogenated styrenic diblock copolymer is from 50/50 to 95/5.
17 . The crosslinkable and foamable composition of claim 16 , wherein the ethylene copolymer comprises an ethylene-vinyl acetate copolymer, an ethylene-α-olefin copolymer, or a combination thereof.
18 . The crosslinkable and foamable composition of claim 16 , wherein the ethylene copolymer is an ethylene-vinyl acetate copolymer, and a content of vinyl acetate is in a range of 15 to 40 wt % based on a total weight of the ethylene copolymer.
19 . The crosslinkable and foamable composition of claim 16 , further comprising a crosslinking co-agent.
20 . A foam obtained by crosslinking and foaming a crosslinkable and foamable composition of claim 1 .
21 . The foam of claim 20 , wherein the foam has a specific gravity of 0.05 to 0.5 g/cm3, a compression set of 30 to 65%, a hardness of 20 to 80, and an impact resilience of 40 to 80%.
22 . The foam of claim 20 , wherein the foam has a specific gravity of 0.05 to 0.5 g/cm3, a compression set of 30 to 65%, a hardness of 20 to 80, and an impact resilience of 55 to 80%.
23 . The foam of claim 20 , which is a component of footwear.
24 . The foam of claim 23 , which is a midsole of the footwear.
25 . A foam obtained by crosslinking and foaming a crosslinkable and foamable composition of claim 16 .
26 . The foam of claim 25 , wherein the foam has a specific gravity of 0.05 to 0.4 g/cm 3 , a compression set of 30 to 65%, a hardness of 30 to 70, and an impact resilience of 40 to 80%.
27 . The foam of claim 25 , wherein the foam has a specific gravity of 0.05 to 0.4 g/cm 3 , a compression set of 30 to 65%, a hardness of 30 to 70, and an impact resilience of 50 to 80%.
28 . The foam of claim 25 , which is a component of footwear.
29 . The foam of claim 28 , which is a midsole of the footwear.
30 . The foam of claim 20 , wherein a method of crosslinking and foaming comprises the following steps:
preparing by mixing the crosslinkable and foamable composition of claim 1 at a temperature at or below 120° C.; and
foaming at a mold temperature of about 150 to 200° C.
31 . The foam of claim 25 , wherein a method of crosslinking and foaming comprises the following steps:
preparing by mixing the crosslinkable and foamable composition of claim 16 at a temperature at or below 120° C.; and
foaming at a mold temperature of about 150 to 200° C.