| Melfores 101 P is an unmodified melamine
formaldehyde powder resin suitable for impregnation of base / decorative papers and
overlay in the manufacture of high-pressure decorative laminates, low-pressure melamine
surfaced wood boards / panels etc. It is soluble in water; clear to slightly hazy
solution. Melfores 101 P can also be used in the modification of Urea glues
by physical blending, for achieving overall improved properties of the wood boards,
especially for enhanced moisture resistance. This is more common in case of plywood
gluing.
Generally, Melfores 101 P content
does not exceed 25% by weight in such mixtures. The powder resin first dissolved in water
and the solution is then blended with the Urea glue.
TYPICAL PHYSICAL PROPERTIES |
| APPEARANCE: |
White free
flowing powder |
| APPARENT
DENSITY: |
0.7 g/cm3 |
| MOISTURE
CONTENT: |
< 3.0 % |
STORAGE
LIFE
of powder resin when stored in original packing, below 20oC: |
> 6 months |
SOLUTION
DENSITY / 25oC:
(55 Pbw powder and 45 Pbw-water) |
1.23 g/cm3 |
SOLUTION
STORAGE LIFE
(55:45 at 25oC) |
5 days
(depends on dilution and temperature) |
| pH OF
SOLUTION: |
9.3 - 10.5 |
| WATER
TOLERATION / 25oC: |
Dilutable up
to 30% solid without precipitation. |
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Preparation of Impregnating Resin Solution:
Generally, aqueous solutions of
40 - 60% concentration by weight of Melfores 101 P are used, however, actual
percentage depends on the characteristics of the paper and the resin pick-up required for
the application.
The requisite quantity is taken
in a mixing vessel fitted with a propeller agitator. The required amount of Melfores
101 P is added in lots with the agitator running and the stirring is continued
until the powder resin completely dissolved to give a uniform clear to slightly hazy
solution. The dissolving process can be expedited by using warm water (40 - 50oC)
Addition of a
small amount of industrial methylated spirit or isopropyl alchohol in the mix (up to a
maximum of 15% replacement of the water) improves the solubility of powder resin, faster
wetting out and reduced effect on the wet strength of the paper, and lower drying time.
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Storage Life of the Resin Solution
The usable life of the
impregnating resin solution is about 5 days, depending on the temperature and dilution. If
the solution is stored for longer periods, it may flocculate or even solidify, which can
normally be re-dissolved by warming to about 70 - 75oC. However, it should be
cooled immediately to the working temperature, under stirring, to avoid further
polymerisation of the resin.
It is strongly
recommended, however, to process and consume fresh resin solutions daily.
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Guidance for Impregnation and Drying of Papers
The resin
solutions based on Melfores 101 P are conveniently used in all types of
impregnating / coating machines. The following typical parameters may be considered as a
guide to process different types of papers for use in the manufacture of laminates.
| Material |
Paper |
Resin Solution
(Concentration) |
Impregnated and Dried Sheets |
Resin*
Content |
Volatiles
Content |
Resin Flow |
Print Sheet
(When used with overlay) |
80 - 140 gsm |
40-50% |
35 - 40% |
4 - 6% |
----- |
Decorative base
sheet
(When used with overlay) |
120 - 160
gsm |
55-60% |
55 - 60% |
4 - 6% |
2 - 4% |
| Overlay |
25 -
40
gsm |
50% |
60 - 70% |
3.5 - 6% |
2 - 4% |
*as percentage of impregnated paper stock
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Drying of the Impregnated Stocks
Drying and further
polymerisation of the impregnated papers may be carried out at about 90 - 145oC
(or higher) in a vertical or horizontal type of drying tunnels and the drying time much
depends on a number of factors such as the type and length of the drying tunnel, paper
through-put speed, resin pick-up, temperature, volatile content, resin flow required on
the impregnated and dried stock etc. It is not practical to recommend optimum drying
schedules with accuracy, but are best standardised by trials under actual manufacturing
conditions.
The impregnated
and dried paper sheets are to be stored under 25oC and 40% relative humidity.
If exposed to higher percentage of relative humidity, there will be considerable pick-up
in the volatile content due to moisture ingress which in turn will affect the flow
properties, surface finish, etc.
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Curing / Pressing Conditions
Generally, curing
is carried out at press temperatures of 135 - 155oC and at pressure range 800 -
1000 PSI. It is also possible to cure under low pressure laminating applications such as
the surfacing of the wood boards / panels. For achieving better surface finish and the
overall improved dimensional stability of the finished products, it is recommended to cool
the laminated sheets, after curing, to about 45oC while still under pressure.
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Post - forming of Impregnated Stocks
Melfores 101 P solution
can be modified by incorporating water soluble plasticisers / flexibilisers at site for
use in the impregnation of paper stocks suitable for manufacture of post-forming
laminates. Generally, such additives content do not exceed 15% by weight. However, the
degree of modification depends on the application requirement.
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Packing
Melfores 101 P is packed
in multi-wall paper bags with inner polyethylene, generally 25 Kgs. net. Higher capacity
packing can be considered, if necessary.
Storage
Melfores 101 P should
be stored in original bags in a dry place and kept as cool as possible (below 20oC).
When stored at higher temperatures, the storage stability will impair remarkably. It is
very sensitive to moisture and hence the bags should be kept well closed to avoid the
formation of lumps.
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© Saudi Formaldehyde Chemical
Company Ltd. 1999
Information in this site is of the best of
our knowledge. However, since conditions under which our products may be used are beyond
our control, recommendations are made without warranty or guarantee. |
