5301 S. Graham Rd.
Saint Charles, MI 48655
989-865-8200 email us
(c) 2005
Lendell Manufacturing, Inc.
Our Services
Our
Production Process
LMI utilizes a truly unique polyurethane production
process for the manufacture of a diverse range of
hydrophilic foam products. Traditional urethane systems
employ a one-shot methodology wherein the two main raw
materials (the polyglycol and the diisocyanate) are
metered and mixed concurrently with the foaming process
with the minimal addition of water. LMI uses a two-shot
process which employs a protic functionally reactive
urethane prepolymer and a separate aqueous phase as the
only two principle components in the foam. The liquid
prepolymer imparts structural integrity and stability to
the foam, while the use of large amounts of water (up to
300% stoichiometric equivalents) allows a wide range of
foam product possibilities. A high speed mix-head
intimately mixes the two components at specific
temperatures, pressures, and weight ratios and dispenses
the pre-foam on a moving conveyer to produce continuous
slab stock hydrophilic foam.
The prepolymer, PrePol™,
is independently synthesized by the combination of a
dialcohol and TOLUENE DIISOCYANATE (TDI). Polymerization
variables include reactant stoichiometries, additives,
temperature exotherms, and mode of addition; all are
intimately related and lead to the specific and unique
properties of PrePol™.
The viscous liquid is stored in nitrogen blanketed
barrels for subsequent use or sale.
The isocyanate end groups of PrePol™
are capable of reacting with any active
hydrogen-containing compound, specifically water, to
generate a cross-linked foam. Because such atypical
amounts of water are incorporated during the foaming
process, any water-compatible component can be
intimately dispersed into the foam. Careful control of
surfactants and fillers allows for a plethora of foam
properties; from soft, resilient, and smooth textured
cosmetic foams to open celled, semi-rigid foams.
As the prepolymer and water mix, the chemical reaction
cross links the polymer chains and expels CO2 gas. The
latter acts as the foaming or rising agent and is vital
to the soft feel and overall density of the foam. The
timing of such dynamic events is important and the final
properties of the system are not realized for up to 24
hours after initial reaction. The slab stock hydrophilic
foam can be cut into various shapes and sizes to meet
the ever growing and diverse product demands at LMI.
