We are at the epicenter of the largest tile production
area in India. In fact, we are the Epicenter. Most of the tiles sold in India
are largely manufactured and supplied from Morbi. However, BA has found many
traders, retailers, sale persons and (surprisingly!)
manufacturers who are not always very much aware of the variety of tiles and
their differences.
We have therefore decided to highlight the Ceramic Tiles
and their variants in a long brief article. Surprised? How contradicting? An
Oxymoron so to say. LONG BRIEF. We know it is puzzling to some and largely
funny to most but yes this series will have articles with LONG BREIFS, because,
we may have to write a hand book to cover everything if we go into the details,
so whatever we will summarize here will be very brief. But as Ceramic tiles
sector has many variants, the article or the series thereof will be quiet long
spanning a number of issues.
To give you an overview of the total series, we will be
covering:
1. Ceramic Wall tiles
2. Ceramic Floor tiles
3. Polished Porcelain tiles
4. Soluble Salts Technology
5. Multi Pipe Technology
6. Salt and Pepper Technology
7. Double charge.
With the preceding list, you will probably agree to our
linguistic adaptation of LONG BRIEF presentation.
Tiles Basics
Ceramic tile
is a complex subject. Let's cut down the complexity and make it simple. There
are two major types of tiles, quarry tile: that is a tile that is made by
extrusion from natural clay or shale and a tile that is made by the pressed
dust method. The pressed category includes wall tiles, mosaic tiles, and floor
tiles. All types of tiles can be glazed or fired as unglazed. Glaze is a
ceramic surfacing material that is used to provide a certain appearance. Let me
restate this point: any ceramic tile type may be glazed or unglazed. This
includes porcelain tiles.
It may be intriguing
to some that how can dust be so strong. When wet dust is pressed under high
pressure, it retains some moisture which helps the body stay together. As all
particles are extremely small and uniform, they compact into a strong body. The
moisture in the tile after pressing is 5%. The tile is then dried and will
still retain moisture of about 2%. Once it is baked in the oven or kiln, its
moisture evaporates and forms a strong body. If the glazing is desired, it
should be applied after drying.
Mostly these
tiles are differentiated on the basis of their water absorption property. Water
absorption of tile is decided by the selection of raw material used for the
body of the tiles and the manufacturing process employed to produce it. In
today’s world a number of technologies are available for manufacture of tiles
and hence there are a number of types of tiles available.
It must be
noted that it is the body that absorbs the water and not the glazed surface. This
water absorption determines the classification of tile.
CERAMIC WALL TILES
A Wall tile
has about 7-20% water absorption. That may be news to some, but it is merely a
fact for the technical experts. This is also the reason why it cannot be used at
a number of places. The water goes into
the body when it rains, dews, from pools and fountains, and even atmospheric
condensation. All these lead to the tile becoming heavy and may even crack due
to temperature variations and the water effect in these variations.
Wall tile is
made for a purpose, sticking on a wall, although in India, people have found
alternative uses for the same, including on floors, where the foot traffic is
very low. A wall tile should be beautiful as it is largely used for Decorative purposes.
Moreover the size must be close to uniform as there is usually a small space
between each tile (called a grout joint).
The relatively soft body of wall tile makes it easy to cut to fit (including
round holes for plumbing fixtures) and helps the tile to stick to the wall
without sliding.
It is normally
argued by laymen that GLAZING is water proof and hence the tiles are safer even
in water logged areas. Yes it is true that glazing is water proof, but water
seeps into the tiles body through GROUTS at the JOINTS. It is worth noting that
the water absorption is in the body and not the glaze. With advancement of
technology, high quality water proofing material can be used to protect the
body of the tiles.
CERAMIC FLOOR TILES
Ceramic Floor
tiles as the name says are manufactured for flooring. The first generation of
Ceramic floor tiles has lower water absorption. This is largely due to better
compaction and very low porosity. Normally porosity and water absorption are
directly related. Lower the porosity, lower the water absorption. The water
absorption of ceramic floor tiles is 5-6%.
As these tiles
are more compact, they tend to be heavier than wall tiles. So, they cannot be
used on walls. Because of low porosity, the cement and mortar cannot bind with
the body of the tile. It is easy to stick the wall tiles which have higher
porosity, on walls, but not these floor tiles.
They can be
glazed and in the Indian context they are actually glazed. This enables the
tiles to be more beautiful and extremely aesthetic. The glazing also prevents
water absorption. However, at the joints, water proofing needs to be done.
The
flexibility of Ceramic tiles is that it can be cut at the site while laying on
the floors.
It is
recommended that these tiles be used indoors and not outdoors as they cannot
resist consistent downpour of water or tremendous foot traffic. They are for
medium range traffic. In high traffic areas, the glazing will give away, making
them futile.
Polished Porcelain Tiles
This is one of
the best inventions of modern day ceramics. These tiles have very low water
absorption- as low as less than 0.5% which is just miraculous. These tiles are
highly compact and dense. They are very much like natural stone and can be
polished similarly. Polishing gives a very good shine to the surface of these
tiles. Moreover, as it is like stone, on further polishing, the tile does not lose
its color. Through the thickness, it has the same color and grain structure.
They can be
used in high traffic areas as well. Homes, Dining rooms, drawing rooms, living
rooms, bed rooms etc. all can be floored with polished porcelain tiles.
They have very
high scratch resistance. They are also very good abrasion resistors. Hence they
can be used in commercial spaces like malls, shopping complexes, airports etc.
Does this mean
that porcelain tiles are the best for all purposes? No. To further elaborate let
us take a look at some of their drawbacks.
Having virtually
no water absorption, they are not recommended for walls. However, if you wish
to use them on walls, the adhesives have to be very good and a good supporting
element in needed in the structure.
Its advantage
is, it can be cut like stone, but you need a special cutting agent of high cost
to cut it and shape it to your purpose of application.
There are
little holes on the surface. These do not absorb and take water downwards in
the tile body, but are not stain resistant. (Though
technological breakthroughs have been made to reduce staining in these tiles.)
These tiles
also suffer from limited color availability. They are found mostly in natural
colors and stone type looks.
Most of these
are quite costly compared to the previous two that we have assessed.
Polished
Porcelain Tiles can further be divided into four categories on the basis of the
manufacturing technology used. These divisions are done to achieve better
designs.
[A]: Soluble Salts
Technology
As already mentioned,
one of the many limitations of polished porcelain tiles is the limited color
availability. SST employs a method to fight this challenge to a certain extent.
In SST, the
soluble salts are dissolved in water. The green tiles are then sprayed with
this water. This forces the water to penetrate within the depths of the tiles.
The printing is done with different mesh size for getting the required designs.
The tiles then pass through three water sprays. This makes the salt penetrate
to 2-3mm in the surface. On firing, the water evaporates and the salt remains
in the tile, giving it a design. This design is visible after polishing the
tile to about 1-1.5mm.
One
major limitation of this technology is that the availability of colors
available is limited to Brown, Yellow, Grey and Green. So, if we want a
replacement of Red Elegante the red
king of Italian marble, SST would fall short.
[B]
An innovation of SST: Multiple Pipe Technology
To
overcome the limitation of SST, multi pipe technology was invented. It uses 3
to 4 color powders to impart print. The powders are applied before pressing,
through the powder feeder. White and Ivory are directly fed on the feeder
grill. This mixture of powders is taken to the cavity of press to feed the
powder and then pressing is done on the tile. So these powders penetrate the
tile, forming delightful designs.
Using
Multiple Pipe tiles is a practical solution. Technically, however, the powders
used in this process are quite costly, making the technology commercially
unviable in many countries. Moreover, homogenous colors were not found in the
produced tiles, which again put off buyers who wanted a large stock.
(C)
Salt & Pepper Tiles
This is another innovative technology, developed to offset the color
print and design limitation of the polished porcelain tiles.
Here, the main body powder, which is Ivory and white, is mixed with
other colored powders, by use of screen vibrators. These powders are chosen
based on the required color of the tile. The tiles are then pressed. The colors
are already mixed with the body, so they form a homogenous mix within the
pressed green tile.
Once these pressed tiles are fired, we get unique black spots on the
tile, as if a lot of salt has been sprayed with a tinge of pepper. This is why
they are known as Salt and Pepper tiles.
The reverse can be done by having Black as the base powder for the body
and white being used sparsely at about 3-4%. This makes the tile totally black
with white spots.
Instead of Black, orange or other colors can also be used, thereby giving
a granular output.
These tiles are used in homes as well as commercial buildings. However,
they still have some color and design limitations.
D]
Double Charge technology: The Presently accepted solution.
The
very popular technology that has replaced both the above technologies is the
DOUBLE CHARGE TECHNOLOGY or the DOUBLE LOADING TECHNOLOGY.
In
this technique 70% of the thickness is manufactured using low cost base powder
and clay. The 30% of the surface side of the tile contains base powder and
three different color powders.
Double
charge or double load means, the cavity is loaded twice. First, only base
powder that is employed for 70% of the tile; then the other base powder and
three other color powders that form the surface. When these powders drop on
grill of the feeder, a uniform pattern is formed as all the three powders have
different density.
Depending
on the feeder grill, different types of designs are formed on the surface of
the tiles. Both these different charges are pressed to make a tile.
To
achieve a balanced combination of Surface patterns, Hardness and Stain
resistance, double charged tiles are upgraded from 1st generation to
3rd Generation. In the third generation, micronized powder is fed
inside the tiles, requiring more pigments and stains, eventually increasing the
cost. However, the final result is three dimensional, a perfect replacement for
natural stones.
In
double loading, the surface with the patter has a very low porosity giving it a
more glossy shine and very less water absorption, compared to SST. The Low
porosity enables it to be highly stain resistant.
Commercial Success
It
seems that Double Charge or Double Loaded technology has proven to be a
commercially viable option. The manner in which many manufacturers are already
manufacturing these tiles and many more are planning to move ahead with the same
certainly portrays a very bright future for this technology.
However,
as the production time and double pressing process add to the costs, there will
always be a big question mark over its long-term sustainability as a solution.
It is believed that till nothing else is there to beat double charge technology
given its cost/value proposition; the technology is here to stay. It seems the
TINA (There is no alternative) factor seems to be working in its favour right
now!
As
we mentioned at the start of the article that humans are always thirsty for things
better and innovative, we are sure, next year in the same period, we may have
something else challenging the Double Loaded technology.
But
for now, it is widely accepted as a great solution for tile manufacturers.
