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PVC - A UNIQUE POLYMER
PVC occupies a unique position amongst the comity of all materials
of construction. It is the only polymer where the basic organic
building block can be extended more than 3 times while converting
into value added end products - the remaining material being
predominantly low cost materials inorganic in nature. It is
the only polymer which transgresses the boundaries of extreme
elasticity to extreme rigidity with a unique range of flexural
modulus values (3 MPa - 3000 MPa) - thereby yielding a versatile
range of products from soft rubber like to very hard metal like
applications. It is the only polymer where 60-70% primary applications
go into very long life (more than 25 years) products thereby
minimizing the waste load on our fragile eco-system It is one
of the few synthetic materials which, while supplementing and
complementing scarce natural resources, have emerged as materials
of construction meeting unique techno-economic requirements
of modern society. PVC is the predominant material that supports
infrastructural requirements across the globe thereby meeting
the developmental needs in this crucial sector; it would be
impossible to conceive modern activities in Building & Construction,
Water Supply, Power Distribution and Telecommunication without
the use of PVC. PVC has also played a very crucial role in meeting
socio-economic needs particularly in developing economies. The
low cost yet aesthetic end products from this polymer have almost
turned around the social lifestyles and societal demands and
in meeting the aspirations of the poorer sections of economy.
No other material can match PVC in its versatile processing
techniques. The polymer can be calendered, extruded into rigid
and flexible profiles, injection moulded, compression moulded,
blow moulded, rotomoulded and slush moulded. It can be coated
by various techniques like spread coating, spray coating, dip
coating, fluid bed coating and it can also be cast. This inherent
flexibility in processing techniques not only yields an amazing
variety of products but also provides impetus in meeting entrepreneurial
aspirations at various levels of skills and investments.
PVC is the world's most thoroughly researched thermoplastic
particularly in terms of Health, Safety and Environment (HSE)
aspects and Life Cycle Analysis (LCA).
Finally, inspite of various sensitive environmental issues and
the adversial role of Green Peace movements, PVC due to technological
developments has not only survived but is indeed slated to be
the eco-friendly star of the decade. Defying the predictions
of several pundits on maturation of these products in the life
cycle we can definitely look forward to strong growth in demand
of PVC not only in traditional sectors but also in emerging
new sectors and applications on the global horizon.
INDIAN SCENARIO
PVC production started in India in the year 1961 when Calico
Industries put up a plant based on Calcium Carbide route. In
1967 the first alcohol based plant was commissioned by Chemplast.
The Company also pioneered the production of paste (emulsion)
grade in the country. The first integrated PVC complex based
on naphtha cracker was established in 1968 by NOCIL. In 1991
Reliance Industries Limited brought about a sea change in local
production with a world scale plant (160 KT enhanced to 300
KT) based on imported feedstock. Today we have an installed
capacity of 750 KT against a demand of 650 KT.
Market share of PVC among the thermoplastics in India is 23%
growing at an annual growth rate of 6-7%. The major consumption
sectors are Irrigation/water supply (38%), Buildings and Construction
(23%), the remaining being used in medical, footwear, profiles,
packaging etc.
ENVIRONMENTAL CONCERN
In recent years, PVC - Vinyls have come under intense scrutiny
on environmental grounds particularly the apprehensions regarding
emission of Chlorine products and dioxins, and adverse aspects
of Phthatates. This note provides authentic information disproving
the widespread misgivings .
VINYL CHLORIDE MONOMER
PVC has been under severe attack for almost 20-25 years when
it was discovered in mid 70s that VCM monomer induces angiosarcoma,
a liver cancer. Initially the problem was restricted to occupational
exposure during manufacture. However concerns were expressed
for risk to human beings. The PVC industry rose to the environmental
challenge in a short time; first to reduce exposure of VCM during
manufacture and then to contain it. The closed reactor technology
coupled with clean reactor systems brought dramatic reduction
in VCM exposure. Further the treatment of VCM by solvent absorption
activated charcoal eliminated the emission to atmosphere. The
occluded residual VCM in PVC particles was brought down from
a level as high as 1000 ppm to the level of 1 ppm by slurry
stripping techniques. PVC industry has passed the critical acid
test. Today most of the PVC produced in the world contains very
insignificant levels of residual VCM. Not surprisingly the Food
and Drug regulatory bodies across the world do not consider
the extremely low levels of VCM in food packaging a human health
or environmental risk. It is even considered to be safe in its
use in medical field.
PVC & DISPOSAL ISSUES - AN INDIAN SCENARIO
Perhaps the biggest contemporary threat to PVC is the issue
of its disposal particularly from municipal solid waste (MSW).
The major volumes of PVC are used in products like Pipes, Profiles
and Cables which have a long life-almost extending upto 50-100
years. PVC in packaging and disposable application (short life
products) does not exceed 10-15% of the total consumption. Latest
figures for 2000-01 show that "short life" PVC Products
form only 8% of total PVC produced. Details are worked out in
the following table. It is therefore not surprising to observe
that PVC component in municipal waste is lowest (less than 0.5%
by weight). PVC on account of its high chlorine content is considered
by the environmentalist to be obnoxious. However the fact remains
that its presence at such low levels in municipal waste streams
could not cause any significant problems. It is argued that
PVC (because of its chlorine) when burnt can form HCI and an
organic chloride product called Dioxin (2, 3, 7, 8 - tetrachlorodibenzo-o-dioxin).
Sectorwise PVC consumption in India
Figures in Thousand tonnes per year
| SECTORS |
2000-01 |
| Pipes |
364 |
| Fittings |
23 |
| Films |
34 |
| Sheets |
14 |
| Roofings |
2 |
| Blow Moulding |
3 |
| Profiles |
17 |
| Flexible Pipes |
22 |
| Cables |
40 |
| Calendered Prod |
34 |
| Blister pack |
17 |
| Compound |
47 |
| Footwear |
25 |
| Medical |
2 |
| Misc |
4 |
| Total |
648 |
In the above table:
* Figures in Bold indicate short term usage items, totaling
up to 54000 tonnes per year.
* Only short-term usage items end up in the MSW
| ANALYSIS OF DATA: for year 2000-01 |
| Total short term usage PVC 54000 Tonnes
per Year |
| So Total short term usage PVC 148 Tonnes per Day |
| Considering total MSW in the Country 100,000 Tonnes
per Day |
| Percent PVC in MSW 0.15 % |
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