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by A.Radhakrishnan, V.R.George Roy & U.S.Sarma, Proceedings of the International Workshop on Wet
Processing of Coir 8-9 December 1997
The output on
Printing on Coir Materials was commenced only after one year of the commencement
of the activities in other outputs of the FAO Project on Softening, Bleaching,
Dyeing and Printing on coir. The
Literature and Industrial Surveys revealed a number of printing techniques in
textiles, but incorporation of designs on coir mats/mattings, rugs could be
effectively made at a low cost only with the stencil.
Printing by all the other printing techniques could not be applied due to
the uneven surface of the coir products
The process of
printing is used to achieve ornamentation and improve the aesthetic sense of the
final product. The coir industry is
an export oriented industry, exporting coir door mats, mattings, rugs, carpets
etc, as decorative floor covering materials.
The designs and patterns with attractive shade connotations are being
applied to these products by printing for achieving more market value and
popularity. The printing method
most commonly adopted in the coir industry is Stenciling. The other printing techniques such as Roller Printing,
Rotating Screen Printing, Hand Screen Printing, Wood Block Printing are not
applied in coir industry due to the uneven surface of the coir products.
Design
development is on of the major needs for the creation of new markets as well as
for upholding the existing markets for coir products.
Designs suitable for the various seasons, suiting the trends and taste of
consumers of different countries has got a great value in the export sector of
coir. The designs evolved by
traditional methods of manual drawing and colouring consumes a lot of time and
energy especially in matching shades and colour mixing of the designs. These designs are made available to the product sector as
design cards for incorporating them to their products. The industrial
survey revealed that newly developed designs evolved for coir products like
mats, mattings, and rugs are transferred to them by two method viz. weaving and
printing. It is a process
of entanglement of warp and weft yarns to form products like mats, mattings and
rugs. Using suitable dyestuffs, the
good quality coir fibre/yarn is dyed in conventional/mechanised dye vats and
processed in traditional wooden looms which require skilled labour.
Weaving require more materials and man power than printing and wastage of
dyestuffs is more than weaving. It is also not possible to make curved lines of
designs on weaving which means that the possibility of making designs by weaving
is limited to polygonal patterns. Printing The process of
printing on coir is mainly based on the use of stencils. For the preparation of
stenciled designs, the sketch of desired design is first prepared in the
required size on paper. It is then
transferred to thin sheet and then cut by hand. It is a stencil plate. Number of stencil plates depend upon the number of colours
used in the design. One plate each for one colour and placed over the mats/mattings
and the dyestuff is applied by spraying or brushing for mats and mattings
respectively. The edges of the stencil plates were guarded with narrow strips of
metal to avoid spreading of dyes while spraying on the coir products.
Care should be taken to avoid over lapping of two colour of the same
design during stenciling. Usually a stenciled design consists of 4-6 colours. The printing
require limited quantity of dyestuffs as it is impressed on the top surface
only. The time consumption and man power is also less and hence cost of
production is low compared to weaving. The Industrial
survey also revealed that creel mats, carnatic mats and fibre mats are the most
common varieties of door coir mats used for printing designs.
Designs can also be applied on these mats using the weaving methods as
detailed below. Cree/Carnatic
Mats:
By arranging dyed yarn in the required colour
combination of the loom It is seen that
the fibre mat is the most popular coir product. The survey confirmed that 20% of
the total production of fibre mat
are marketed as plain mats whereas 80% as woven or printed design mats in
the ratio 40:60 About half (50%)
of the total production of Carnatic/Creel mats are marketed in woven or printed
designs and the rest is in plain form. Almost
all the designs in the above mats are stenciled one due to the practical
difficulties involved in the arrangement of dyed yarns during the weaving
process. The survey also
brought that the consumers are very conscious on printed design on coir which
should be fast to light, washing and rubbing. The taste of consumer is also aimed at
in buying coir products containing eco-friendly dyes/pigments which would not
release the toxic amines.
A list of the
dyestuffs, plastic emulsion paint and synthetic enamel paint used for evolving
floral designs and depicting nature’s beauty by stenciling on creel/fibre coir
mats are furnished in Annexure I Based on the
industrial survey of traditional designs used in coir floor furnishing
materials, it is felt that a major modification is essential in terms of pattern
layout and colour. An album was
made by incorporating the designs evolved for coir products. In
the experimental stage, two types of paints were applied on coir mattings b)
Synthetic enamel paint which is based on a volatile organic solvent. The ready mixed
emulsion/paint, suitably diluted was sprayed on the mattings and the coated
materials allowed to dry in air. Sample cuttings of the shades were exposed on
the Xenotest for the determination of the light fastness. It was observed that
after a slight initial dulling after six to eight hours of exposure there was no
further change in the tone. Suitable length
of the mattings sprayed with the paints were also fixed on to the staircase and
elsewhere to examine the behavior of the coatings under service conditions.
The synthetic enamel paints are observed to abrade or wear off slowly
from the surface resulting in the loss of the gloss or lustre of the film.
With the plastic emulsion paint, the colour is rather subdued, but
comparatively this offers greater resistance to abrasion or wear.
Both the types of paints sprayed and dried on the mattings show excellent
fastness to water. It is of
interest to note that due to the opaque nature of the film one could overprint a
light colour design on a dark coloured background or vice versa using plastic
emulsion paints for the purpose. The application of the paints would be
particularly worth while for producing coir mattings in pastel shades, which are
reportedly in good demand in overseas markets. The specimen of
door mats were stenciled with synthetic enamel paints and coir dyestuffs so as
to achieve different shades to evolve floral designs and nature’s beauty.
These printed designs were exhibited in trade fairs for assessing the
receptivity of consumers. Photographs
of the printed designs were made into an album for reference of the exporters. In
another experiment an apple design was printed with the following receipe based
on reactive dyestuff on fibre mat.
The reactive dye
stuff solution was sprayed on the mat and subsequently dried in room
temperature. It was observed that
the penetration was deeper coupled with brilliant hue. The light fastness was
also measured by subjecting the mat in direct sun light for 15 days. It was observed that the fading occurred to the extent of
only 10% which is better when compared to the traditional printing with basic
dyestuff. The cost aspect
of the printing was calculated at Rs.1.05 to cover 75% of the total area of the
mat. The cost details are furnished
in Annexure-II
Stencil Printing
is the most widely adopted technique
for incorporating designs on coir mats/mattings. Synthetic enamel paints and
reactive dye stuff can be used for achieving prints of better light fastness and
deep penetration. It is desirable to adopt computer Aided Design (CAD) system in
coir industry also for effecting maximum efficiency, speed and accuracy
involving designs suited to the taste and trend of people of different countries
by blending of colour combinations and make copies of designs. It is
advantageous to use eco-friendly dyes so as to avoid the release of toxic and
banned amines. The use of dye
derived from natural resources such as plants, insects, and minerals on coir are
to be encouraged. The designs
already evolved should be transferred to coir materials for assessing the
marketability and receptivity among consumers.
The authors are
indebted to the FAO for extending the assistance in conducting the project and
grateful to the Coir Board in permitting to publish this paper. Reference 1.Terence Conran:
Printed Textile Design, Industrial Printing methods P 13,14 2.Standard
methods for the determination of the colour fastness of Textiles,Colour
fastness to day light P.46-50 3.Dr.Lous
Diserens : The chemical Technology of Dyeing and Printing
Basic Dyestuffs. P.84,Acid Dyes,P.311-315,
Pigments, P.370-410 4.ICI-Procion
Dyestuffs in Textile Printing, Printing of Cellulosic fibres P.1-10 ANNEXURE-1 DETAILS OF MATERIALS USED FOR PRINTING DESIGNS ON COIR
PRODUCTS 1.
Synthetic enamel paints 2.
Compressor/spray Gun 3.
Dye stuffs 4.
Urea 5.
Sodium bicarbonate ANNEXURE-II COST
PARAMETERS OF PRINTING WITH REACTIVE DYESTUFF
Cost
for printing one mat
: Rs.1.05
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