The waste obtained at the bottom of the
distillation tower used in caprolactum recovery contains trapped
caprolactum along with oligomers. After segregating the capralactum
rich waste and oligomer rich waste, the caprolactum rich waste,
which is soluble in water at room temperature, is subjected
to chemical purification and distillation for recovery of
caprolactum. The oligomer rich waste containing both cyclic
and linear oligomers was found to be polymerisable to moderate
molecular weights under controlled reaction conditions. This
material is subjected to either homo and/or co-polymerisation
to produce different types of adhesives and coatings.
Introduction
A specific quantity of Oligomer waste consisting
of cyclic and linear oligomer is taken in a reactor to which
a specified amount of water is added and heated in a heating
bath. Inert gas, preferably Nitrogen is flushed into the reactor
and the temperature of the reaction is raised. After maintaining
the temperature for the desired period a weighed amount of
Manomer I is added. The reactor is heated up again to raise
the temperature to the desired level and maintained for about
30 minutes. Subsequently a weighed amount of Manomer II is
added and the reactor is heated further for attaining another
desired level of temperature. The temperature is maintained
at this level for a specific duration with or without vacuum
so that the required copolymer, Nylon 6 : Polyester or Nylon
6 & 66 is produced. In the case of Homopolymerisation,
nitrogen is flushed through the empty reactor first followed
by the addition of oligomeric waste. The reactor is then fixed
with a stirrer and placed on a heating arrangement. Subsequently,
the reactor is charged with Oligomeric waste and heated with
continuous stirring. On attaining the desired temperature
in about 30 minutes and allowed to remain at this temperature
for a specific duration, homopolymer of desired molecular
weight is produced. The polymers as obtained by the process
described above have been tested for end use application,
particularly as hot metal adhesive by known methods. The lap-shear
and T-peel tests carried out have demonstrated better adhesive
strength which may be attributed to the random structure of
the prepared polymers.
Special Features
Conversion of oligomeric waste or polymeric
waste into a useful hot metal adhesive; Additional step involving
addition flow agents and/or plasticisers as practiced in the
conventional method is eliminated; Reduction in production
cost; Can be used for treating oligomer or polymer waste from
both caprolactum recovery plant as well as nylon 6 processing
units.
Prospective Users
The method is useful for (i) Caprolactum
processing units for producing a valuable by-product (ii)
small/medium chemical industries for conversion of nylon polymeric
and oligomeric waste material to a useful product.
Type of Technology:
Process
Status of Development
Investigations have been carried out in
collaboration with Caprolactum processing industry. Process
has been developed for producing hot metal adhesive The end
product, viz., the hot metal adhesive has been tested as per
ASTM D1876-61T and found satisfactory. Scaling up can be easily
carried out. The process could also be used for the production
of moulding material and coating materials for metals.
Requirement of
Raw Materials/Components:Stainless
Steel batch reactor having a capacity of 800 kgs. with heating
capacity upto 300 deg. Centigrade Vacuum system to be fitted
to reactor to provide pressure of 0.1 mm Hg High power stirrers
Requirement of
Utilities:Electricity Treated
Water
Contact
Managing Director
Foundation for Innovation and Technology Transfer (FITT)
Indian Institute of Technology, Delhi
Hauz Khas, New Delhi-110016, INDIA
Tel : 91-011-26597167, 26857762, 26581013, 26597153
Fax : 91-011-26851169
E-mail : drkdpn@gmail.com
