--
Applications
LIWEI CHEMICAL CO. LTD
Usage | PVA type |
Adhesive | PVA2499/2699/1788/2488/2099 |
Sealant of type | PVA2499/2699/2688/2488 |
Adhesive of paper | PVA2499/2699/1799/2099/1788/0588 |
Plywood/ timber processing/ Man-made board | PVA1799/2099/2499 |
Emulsion Stabilizer | PVA2499/1899/2099/1799/1788 |
Construction | PVA2099/2488/0588/2499 |
PVA film | PVA2099/2499/1795/1788 |
Hydrophobic fiber | PVA1799/2095/1795 |
Hydrophilic fiber | PVA1588/1788/2088 |
Printing | PVA2488/1788 |
Non-woven agents/ architectural coating | PVA1799/2499/2699 |
Casting Industry | PVA1788/ |
Agriculture | PVA1788/2499/2099 |
Glue | PVA1788 |
1.
PVA Film
Polyvinyl Alcohol Film
has many unique advantages unmatchable for general polypropylene and
polyvinyl chloride due to its properties of bearing static
electricity, good optical transmission, good gloss, low oxygen
permeability, and coriaceous coating.
In this sector traditional varieties are seldom used. Due to low
viscosity of
PVA 1799
series, generally for membrane not easily soluble,
PVA 2099
and
polyvinyl alcohol 2499
may be used, whereas the PVA 1795 and
PVA 1788
may be often used for production of water-soluble membranes.
2.Papermaking & Processing
In papermaking, water-soluble polymers are mainly applied to surface
sizing agent, pigment binding agent, and paper addictive. In the
past starch-based pigment was used as a surface sizing agent and
casein as a binding agent. Today since the adhesion of
PVA fibers
is stronger than casein, with better film-forming property and
higher intensity of the film, the demand of PVA for paper processing
is on the rise. Along with the large-equipment involving, high
efficiency and high-grade papermaking and reasonable ways of
packing, such demand will be even greater. Main applications: (1)
binding agent for paper; (2) re-moistening agent; (3) paper surface
sizing; (4) paper pigment coating; (5) papermaking (paper internal
sizing). Applicable varieties: PVA 24-99, PVA 20-99, and PVA 1788
etc.
3. Plywood, Artificial Board and Timber Processing
PVA Polyvinyl Alcohol
can be a de-characterizing agent of thermosetting resin mainly used
as a binding agent such as carbamide, formaldehyde resin and
melamine, for plywood, artificial board and timber processing. When
mixed with melamine-formaldehyde resin, the PVA size paste helps
increase the viscosity and shortens both curing and cooling time
with stronger initial cohesion. Commonly used varieties: 1799, 2099,
and 2499 etc.
4. Emulsifying and Stabilizing Agents
With its very low surface tension and its ability to disperse VAC in
water into very fine granules, PVA is applied to produce PVAc
emulsion. It is also a very good protective colloid that enables the
polymerized, colloidal and granular PVAc to form a stable aqueous
emulsion and keep it from coagulation or degradation. Selection from
a variety of PVA products depends on their properties. As for latex
with a strong cohesion at the beginning of production, the complete
alcoholysis type PVA can be selected, such as those labeled 2499,
1899, 2099 and 1799; on the contrary, for production of latex with
low viscosity despite high content of solid, a PVA with a low degree
of polymerization may be mixed with a PVA with high alcoholysis, and
0388 can be used together with 1799.
5. Construction Industry
Polyvinyl alcohol is used as an addictive to cement and mortar for
efficient increase of their cohesion and fluidity, and reduce the
drying time for the concrete surface, thus increasing coating
adaptability and preventing concrete cloth from chapping. Besides,
due to its simple application method with desired effects, PVA is
suitable for wall and ceiling decoration and tile facing.
PVA can be also used as an adhesive agent for profiles, e.g.
prefabricated plasterboard and sound absorption board that are made
of organic fibers (cane, residue and wood-shavings) or non-organic
materials on which highly cohesive and waterproof PVA series can be
applied to make profiles through compression and cohesion.
The PVA solution, a poly vinyl formal PVFM high molecular compound,
finds its wide application in internal wall coating, plasterwork and
joint sealing due to its favorable properties of weather resistance,
waterproof, non-swell with water, non-embrittlement, non-poison,
tastelessness, and inexpensive prices.
In the coating sector the traditional varieties can only be used in
making profiles. PVA with a higher degree of polymerization, such as
the models 20-99 and 24-99, are often selected as a substitute.
6. Printing
For the PVA film which contains dichromatidgelatin or cinnamon acid,
after ultraviolet radiation, part of the PVA combines with
dichromatidgelatin to produce insoluble complex salt, or with
cinnamon acid to have a water-insoluble meshwork due to the bridging
effect. After heat treatment for increase of physical strength, the
meshwork can be used for screen printing.
7. Textile
Functional PVA is now the most efficient synthetic sizing agent for
warp paste with the following advantages:
(1). PVA membrane has a good sizing effect and can improve the
weavability of high-density and high-grade textiles due to its
excellent properties of obdurability, smoothness, wear resistance
and adhesiveness on fibers.
(2). PVA has a powerful cohesive force on fibers as well as good
protective effects to reduce times of textile yarn breaking and
improve weaving efficiency.
(3). PVA size paste doesn’t not get corrosive easily and degraded
without any change in viscosity after long-time heating, which
ensures stable sizing and minimizes hard size spots.
(4). At textile factories the moisture of starch paste must be at
80-85%, while the moisture requirement for PVA size mixture is just
70-75%, which makes it possible to improve operating environment and
production efficiency.
(5). To minimize desizing in the process of sizing and weaving and
keep the factory area clean, PVA series with medium degrees of
polymerization and 90-97 (mol/mol)% alcoholysis, such as 20-95 and
17-95, are applicable.
8. Vinylon
Polyvinyl Alcohol PVA fibers
can be used to made vinylon.Though the clothing property of vinylon
may be far less popular than other synthetic fibers, Vinylon is
still known for its properties of moisture absorption and wear
resistance and can substitute some cotton-made bedding, knitwear,
decorative cloth, canvas, uniform, work clothes, fishing net and
curtain. Other properties of vinylon meet industrial requirements,
such as high strength, low elongation, high modulus,
acid/alkali/weather resistance, good adhesiveness to rubbers. So
high-strength and high-membrane vinylon can be used as an
alternative to asbestos.