ISOPA-FACTSHEET Recycling and RecoveryPolyurethanes V02

FACT SHEET
RECYCLING AND RECOVERY

POLYURETHANES
Rebonded Flexible Foam
Bonded foam, or rebond, is a moulded poly- Typical bonded foam equipment using
urethane product made from pieces of shredded batch moulding process
flexible polyurethane foam, held together with
a binder. Its relative high density and excellent
resilience make it suitable for applications including
vibration sound dampening, flooring, sport mats,
cushioning, packaging and carpet underlay. In fact,
rebond has been in use for decades. Up to 50,000
tonnes of rebonded foam are processed each year
in Western Europe and new applications are con-
stantly being developed.
Typical bonded foam equipment using continuous moulding process
Bonded foam properties can be varied over a wide

Foam pieces from various sources - production
range by careful selection of base material, particle
trim and post-consumer waste - can be suitable
size, compression ratio, type and quantity of the
for rebonding, although in practice production
binder. As a consequence, rebonded flexible foam
trim and cuttings are by far the most commonly
is gaining acceptance in applications which so far
processed. Granulators and flock-mills are normally
could not be satisfied by virgin foam material.
used to shred the foam into pieces approximately
The Process one centimeter in diameter. There are other
technologies available to handle large foam pieces
o foam collection and sorting by cutting them into very thin strips, which can then
o shredding be reduced into smaller pieces.
o coating with adhesive binder The ISOPA Fact Sheet “Options in Practice” lists
o compression to desired density and shape companies which are practicing foam rebonding.
The technologies used vary according to the market
o activation of adhesive binder requirements and the final use of the rebond articles.
o curing of adhesive binder
Rebonding of polyurethane foam can be carried
o converting of rebonded foam parts out through batch or continuous moulding. The
foam blocks are further processed to fabricate parts
and articles, resulting in trim which in turn can be
reused in the process. Rebonding is also applied
in the moulding¬-to-final-shape technology which
allows processors to optimise material use and cost.
RECYCLING AND RECOVERY
POLYURETHANES
Rebonded Flexible Foam
From a storage hopper, the small foam pieces are Rebond characteristics
fed into a blend tank by means of an Archimedean
The quality of rebond depends on several factors like:
screw. In the tank, the foam is sprayed/mixed with
a polyurethane binder. Once coated with the binder, o the types and grades of the foams used
the foam is fed into a mould. In the batch process,
o the particle size and uniformity of the shredded
a rectangular or cylindrical mould is used. A piston
foam pieces
compresses the foam in the mould to the desired
density. Steam is then introduced to activate and o the density required of the end product
cure the binder. After curing, the mould can be
o the quality of the binder
opened, the rebond removed from it and allowed
to dry. o the binder / foam ratio
Typical physical properties of rebonded foam
Density kg/m³ 60 - 300
Tensile strength kPa 40 - 150
Elongation at break % 40 - 90
CLD hardness at 10% compression 4 - 20

at 25% 5 - 50
at 50% 15 - 150
Where a continuous moulding process is used, the

foam binder mixture is deposited from the blend
SUGGESTED READING
tank onto a moving conveyor. Another conveyor ‘Rebonded Foam on the Basis of an NCO Prepolymer’,
Bayer; March 1987
is positioned above this so that the mixture is
compressed as it passes between them. ‘Basics of Bonded Foam’, Dow Plastics, 1991
(Form No. 109-01506-591 SMG)
Conventional cutting and peeling processes are used ‘Remotec Product Information’, Hennecke Polyurethan
to turn the rebond into finished products. ¬Anlagetechnik, October 1995
Recycling companies are kindly invited to submit to ISOPA their references in case they are active in practicing
PU recycling and recovery.
ISOPA
Avenue E. van Nieuwenhuyse 4, Box 9 Brussels 8-1160 Belgium
Tel: +32 2 676 74 75 - Fax: +32 2 676 74
Email: main@isopa.org - Website: www.isopa.org
ISOPA - the European lsocyanates Producers’ Association - is an affiliated organisation within the European Chemical Industry Council
(CEFIC).
Since the original polyurethane material has not been designed for use in articles in contact with food, relevant EU (such as Directive$90/128/
EEC) and nationallegislations need to be consulted, if and when recycled materials are used to manufacture articles and goods for possible
direct and indirect food contact.
The information contained in this publication is, to the best of our knowledge, true and accurate, but any recommendation or suggestions
which may be made are without guarantee, since the conditions of use and the composition of source materials are beyond our control.
Furthermore, nothing contained herein shall be construed as a recommendation to use any product in conflict with existing patents
covering any material or its use.

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FACT SHEET

RECYCLING AND RECOVERY

Typical bonded foam equipment using continuous moulding process

Bonded foam properties can be varied over a wide

Typical physical properties of rebonded foam

Density kg/m³ 60 - 300

Tensile strength kPa 40 - 150

CLD hardness at 10% compression 4 - 20

Where a continuous moulding process is used, the

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