PVA Water Solubility

Water solubility of PVA differs a little with different alcoholysises and viscosities. Based on the characteristics of our products, it’s suitable to adopt the dissolving procedures as follow:

1. Add a moderate amount of clean water into the dissolving kettle on condition of room temperature. The temperature shouldn’t over 30℃.As the hot water can form masses which will extend the dissolving time.
2. Add calculated PVA into the dissolving Kettle little by little (better in average and slow speed) and fully stir it. The stirring speed should be controlled at about 80- 100 revolutions per minute, and keep it soaked for 30-60 minutes after finishing stirring.
3.Rising the temperature slowly to 85℃(partly hydrolyzed) or 90℃ – 95℃(totally hydrolyzed)
4. Heat with steam to a proper temperature step by step, and at the same time, keep stirring till PVA is completely dissolved. Heating can be done directly on an open fire without steam, but the density of the mixed liquor can never be higher the 10%. Remember constant stirring can prevent it from being burnt. The right temperature for PVA of thorough alcoholysis is between 95c and 98c, and no boiling has to be dome. Heating to 60c may do to PVA 17-88.
5. Methods to distinguish whether PVA is completely dissolved:
a. Base on the operating experiences.
b. Put some dissolved PVA liquor in a beaker, and observe it in a bright place, if it’s clear and no transparent particles can be seen, and then PVA in the kettle is completely dissolved.
c. Measure the viscosity. The viscosity of the liquid won’t change under the same condition after about 30 minutes.
6. It is natural to blister when PVA is being dissolved. Heating and stirring at interval can be done if this phenomenon is serious, or lower down the dissolving temperature and stirring speed of revolutions to a proper degree. (If necessary, a moderate amount of deformers, such as caprylic alcohol and tributylphosphate can be added in.)
7. When the dissolution of flaky PVA is coming to the end, flow down from the kettle is to be employed, and the valve at the bottom must be opened and part of the bottoms have to be let out (This part can be put into the kettle again for dissolution). So that the valve at the bottom is unblocked.

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Analysis and treatment for frequent abnormal phenomena occurring in PVA use

Abnormal phenomena
Analysis
Solution
Glomerate  occurs in PVA

solution or solution in yellow

1. Not be soaked before dissolving or

feed into the hot water directly

2. Not agitate in a timely manner

3. Temperature raising speed is too fast

4. The dissolving temperature in

early stage is too high

1. Soak at room-temperature

for 30-60m before dissolving

2. Agitate while feed material

3. Raise temperature slowly,

prolong the dissolving time properly

4. The dissolving temperature

of completealcoholysis product

is not lower than 98?

The concentration of pva is

too low or too high

1. Fed water is excess or skimpy,

or added PVA is skimpy or excess

2. The type or specification

of PVA is impropriety

1.Add PVA or water to suitable

concentration

2.Change PVA

Foam mass occurs

when dissolving PVA

Temperature is too high, or it

is raising speed is too fast.

 

Control the speed of raising

temperature,drop the temperature

, add adequate defoamer or keep

the PVA solutionholding for defoaming

After dissolving for a long time,

there is undissolvable grain still

PVA contains trace insoluble ingredient.
Filter the dissolved PVA(120 mesh)
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PVA consumption trends

Polyvinyl Alcohol PVA chemical formula is [C2H4O]n, white sheet, wool or powdered solid, odorless. Physical properties of polyvinyl alcohol effects of chemical structure, alcohol sis, degree of polymerization.
Solubility: insoluble in petroleum ether, insoluble in water. Derivatives of cellulose and starch, synthetic resins, and a variety of surfactants are miscible with each other and have good stability.
At room temperature, its aqueous solution pH value is typically at around 5-7, viscosity stability, almost independent of weak acid, weak alkali or organic solvents (esters, ketones, higher alcohols, hydrocarbons) effect, extremely high oil resistance

The use of PVA
1, The vinyl raw material: polyvinyl alcohol after dissolution, spinning, and then of the acetal with Pooh fibre, it is compatible with, such as cotton, wool, viscose blend made from vinyl textiles, widely used in clothing, tarpaulin, curtain line, fishing net rope. In General, the selected average degree of polymerization of 1750 ± 50 PVA17-99 raw materials as well as spinning.
2, Warp slurry
1) dominated by PVA modulation paste, cotton, linen, polyester and vinylon viscose has a good adhesion, smooth after filming, both robust and wear-resistant, promote well-weave of warp and warps in the weaving process friction reduction, bending. Stretch warp caused by steroid such as break, reducing machine breakage rate. Feel neat and weave cloth. Smooth and delicate, oil on canvas is not rough.
2) Polyvinyl alcohol is a water-soluble polymer , mixing , sizing , desizing are very convenient
3) General election low average degree of polymerization of polyvinyl alcohol ( eg PVA15-99 ,16-99 ,17-99) as a slurry is good.

3, Binder
1) cellulose, polyvinyl alcohol 1788 water solution containing material (such as paper, cloth, wood, etc) very strong adhesion, had the advantage of safe non-toxic, can be used for Board-laminated, adhesive for corrugated board and Office with glue. Packing heavy loads such as kraft paper bags for cement, fertilizer, food and other using PVA as Binder.
2) PVA modified urea-formaldehyde resin and phenolic resin can be used as floor panels and Panel adhesives.
3) PVA water solution (by adding suitable fillers, additives) is also widely used in preparation of printing and binding, paper, carton and other paper adhesive needed for the connection.
4) and polyvinyl alcohol under acid catalysis,, butyric aldehyde, Glyoxal and formaldehyde other aldehydes or condensation, can generate more water resistance, adhesion, mechanical strength of polyvinyl-formaldehyde (such as PVAF, PVB) is widely used in safety glass sandwich construction, paints, adhesives, and other fields. PVA polymerization degree increase, Acetal viscosity increases
PVA Market
United States the main consumption areas of adhesives and textile sizing, 76% per cent of total consumption
European consumption aggregate additives, and paper coatings, 68.7% per cent of total consumption
Japan’s major consumer areas are fibers, adhesives, 72% per cent of total consumption
2012 global polyvinyl alcohol consumption of 1.184 million tons, North American consumption of 156,000 tons, per cent of the global total of 13.18%; Western European consumption of 154,000 tonnes, ratio of 13.01%; the Asia-Pacific region is the world’s largest market for polyvinyl alcohol, annual consumption of 822,000 tons, 69.43% per cent of the global total.
In recent years, the steady growth in world consumption of polyvinyl alcohol
1, Textiles: requires less abroad with or without PVA as a paste, modified starch alternative part of the PVA, PVA textile-related needs may be gradually reduced:
2,Adhesive: basic maintenance of stability, as represented by the 24 series will gradually increase with high viscosity, 17 series as the representative of the demand will be reduced:
3,Paper: gradual reduction in global demand, but on domestic products, future varieties with low polymerization degree can earn a certain amount of market share:
4, PVB: increased demand for high quality requirements;
5, Fabric: with its unique performance of high strength, high modulus fiber, as well as alternatives, such as asbestos, their demand will rise sharply;
6, Other: includes biodegradable materials, liquid-crystal display steady growth

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PVA market analysis——USA&CHINA

Polyvinyl Alcohol PVA is a sort of water —soluble macromolecule polymer.It has innocuity and biodegradation excellent performance ,and completely accord with modern society requirement to environment —protection product. Its water solution has good agglutinating value and film formation ;it could resist most of organic solvent such as oil,lube ,and hydrocarbon on ;it possesses chemical property such as etherify ,a etherify ,and contact Alde Hyde .It mainly used to manufacturing PVB ,oil —p roof pipe ,and Vinyl on fibred ;it also used as ad save for temporary protection fin and leather ,and use as glue feed for binding etc .China has already become maxim al P VA production capacity ,yield ,and consumption country .PVA production is almost balance account for world gross about 50 %
Application
Due to PVA excellent performance, is currently widely used in pharmaceutical preparations, with good results, mainly used in the following aspects:
1 ) as a release agent layer forming material ;
2 ) used as the matrix in Papua paste ;
3 ) as the matrix used in gel formulations ;
4 ) as the binder system of tablets , matrix material and the drug-loaded microspheres or microcapsules or dispersion medium containing porogen.

U.S. PVA market
In recent years, changes in alcohol consumption in general are not particularly large. , In 2009 consumption was l2.20 million tons, accounting for the world’s total consumption of polyvinyl alcohol 11.58%, representing a decrease of approximately 13.47%, of which PVB on polyvinyl alcohol consumption was 41,000 tons / year, accounting for 33.61 percent of total consumption is expected 2009-2014 polyvinyl alcohol consumption in the United States will average growth rate of approximately 4.90% to the total consumption in 2014 will reach about l5.50 million tons. PVB which average annual growth rate of demand for polyvinyl maximum will reach about 10.65% , followed by adhesives, demand will reach an annual growth rate of approximately 2.90 %, while in terms of textile pulp but the demand will average about 1.75 % of the speed reduction

China PVA market
China has become the world’s largest PVA production capacity and output, but also the largest consumption country, production of about 520 000 t / a, the basic balance demand, accounting for about 50% of the world total. But the current production of varieties is relatively simple, the majority of ordinary viscosity and alcohol sis of conventional products, mainly used in construction adhesives, low-grade textile pulp and other fields.
Currently particularly high or particularly low degree , low degree of alcohol sis fine and special varieties of high production technology no major breakthrough , such products market is dominated by Japan , the United States and other manufacturers possession. China’s economic development for the PVA new product development to provide a broad space for development. According to statistics, in 2007 PVA National Statistics actual production was 500,000 t, but the annual import volume is still about 40,000 t , while imports are high in this part of PVA fine and specialty products , expensive , lucrative one . Polyvinyl alcohol consumption since 2012 the situation is more optimistic. A long time in China’s economy will maintain rapid development ask the backdrop , PVA demand will maintain steady growth.

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Film Formation of PVA

Polyvinyl alcohol is one of the few synthetic water-soluble high molecular polymers. Its indexes mainly include the degree of polymerization, the degree of alcoholysis and other special performance indicators. The main production process of PVA is: vinyl acetate is polymerized to form polyvinyl acetate, and then subjected to alcoholysis to form polyvinyl alcohol.

The PVA aqueous solution is easy to form a film, and the formed film is colorless and transparent, has good mechanical strength, and the surface is smooth and not sticky. The film is permeable to water vapor, but the permeability of gases such as hydrogen, oxygen, and carbon dioxide is very low, and the change in external temperature has little effect on the film.

Our company-BouLing Chemical Co., Limited specializes in the production of polyvinyl alcohol and other products, with a wide range of products and abundant supply. Our products are supplied to foreign markets and have a good reputation in foreign markets. If you are interested in cooperation, please contact us.

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Advantages of polyvinyl alcohol

Polyvinyl alcohol BF-17 powder is a water-soluble and environmentally friendly macromolecule polymer, non-toxic and non-polluting binder, which is produced by acetylene method of calcium carbide, petroleum and natural gas with advanced technology and technology.

The series of products (polymer powder) can be dissolved directly in cold water.Pulverized polyvinyl alcohol (PVA) is added to paper making, beating and papermaking together with pulp, so as to produce paper with high strength. It is better to choose polyvinyl alcohol with higher average degree of polymerization.

Our company-BouLing Chemical Co., Limited specializes in the production and development of polyvinyl alcohol series products, if you need, you are welcome to contact us. Or you can choose to visit our company’s website, which contains detailed product information and company information.

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