Scorch-Proof Polyurethane Foams


 Number/Link: WO2018/064521

Applicant/Assignee:  Vanderbilt Chemicals

Publication date: 5 April 2018

Gist”: A synergistic mixture of antioxidants prevents scorch

Why it is interesting: “Scorch” is a discolouration of the center of (especially low-density flexible) polyurethane slabstock foams as a consequence of excessive heat build-up during production. It is believed to be the result of free-radical reactions of foaming components and additives, like the dimerisation of BHT – a common antioxidant. According to this invention the combination of three to (optionally) 5 specific antioxidants show an unexpected synergy towards prevention of scorch. The inventive composition consists of 2,2,4-trimethyl-1,2-dihydroquinoline, a lactone (e.g. 3-alkyl- benzofurane-2-one), a phenolic compound (e.g. an alkylated monophenol) and optionally a tocopherol (a vitamine E-type phenolic compound) and a phosphite compound.  The composition is said to have the added advantage of showing low volatile chemical emissions.



Flexible Foams from Inverse NOP Prepolymers

Title: Polyurethane Foam


Applicant/Assignee: Green Urethanes

Publication date: 06-11-2014 (priority PCT)

Gist”: Flexible polyurethane foams based on OH-ended natural-oil polyol prepolymers

Why it is interesting: Polyols based on natural oils (NOPs) such as rapeseed-, soy-, castor oil and the like are hydrophobic, have sterically hindered hydroxyl groups and are therefore not compatible with conventionally used polyols and isocyanates.   The amount of natural oil-based polyols that can be used is therefore limited to less than about 30% for conventional flexible slabstock and even less (5-10%) for HR foams. According to the current invention, prepolymerizing the NOP with a multifunctional isocyanate to form an OH-ended (‘inverse’) prepolymer, improves compatibility and reactivity and even reduces or eliminates the typical smell associated with these compounds. In the examples about 10% of the OH groups of different types of NOPs are pre-reacted with polymeric MDI using a gelling catalyst.  The prepolymers are then foamed using TDI, water and conventional polyols. Flexible foams are produced containing 50-75% NOP on the total amount of polyol used.

Castor Oil

Typical castor oil component