High melt flow hydrogenated styrenic block copolymers

Abstract

A viscosity-reducing and cracking hydrogenated styrene block copolymer (m-HSBC) is provided. The m-HSBC comprises at least one vinyl aromatic block S and at least one rubbery block R derived from a hydrogenated diene unit. It is prepared by a controlled chain scission reaction of an HSBC precursor. The chain scission process forms a low molecular weight substance and increases the melt flow rate (MFR). The molecular weight (Mp) of the main peak of the m-HSBC by gel permeation chromatography (GPC) is 10-200 kg / mol, the residual unsaturation (RU) is at most 0.5 meq / g, and the melt flow rate (MFR) at 190°C / 2.16 kg is 10-2000 g / 10 min. The m-HSBC can be functionalized with anhydride, epoxy, silane, or (meth)acrylate groups. The m-HSBC or functionalized m-HSBC exhibits high MFR, good elasticity, and improved substrate wettability. These materials are suitable for adhesives, sealants, coatings, copper clad laminates (CCL), and other melt processing applications.

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