Process requirements for solvent used in spinning stock
1 Consider from technology
The solvent must also make the concentrated solution have good rheological properties.The lower the viscostly of a solution of equal concentration or the higher the concentration of a solution of equal viscostly.
2 Economic effect and labor protection consideration
Boiling poit should not be too low or too high,usually the solvent boiling poit in the range of 50-160 degree is better.If the boiling point is too low.it will cause waste due to volatilization and pollute the air;If the boiling is too high,it is inconvenient to recycle.
The solvent must be thermally and chemically stable enough not to decompose in the recovery process.
The solvent is required to have low toxicity and low corrosion to the equipment.
In the process of dissolving the polymer, the solvent does not cause damage to the polymer or other chemical changes.
At present,some solvents used in production are more or less unstalble,toxic,difficult to recover,expensive and other disadvantages.An alternative to volatle solvent ionic liquid(Ionic Liquid),is under research and development.
Ionic liquid are organic liquids composed entirely of ions at room temperature and adjust temperature ranges.Ionic iquid has very strong,non-volate,not easy to oxidize,non-flammable and explosive,inorganic and organic compounds have good solubility and stability to most of the reagents and other excellent characteristics,so it is called green solvent.
The solubility of polypropylene wax in concentrated salt water shows that concentrates salt water is a polar sovent,which is generally a good solvent of polar hyperpolymer.And its solubbility to the polypropylene eyeball reaches an optimal value at a certain concentration,when the salt ions almost all solvated
In addition,adding some additives in the solvent can also increase the solubility of polypropylene wax.For example,adding zinc chloride,calcum choride and other electronic in the solution can increase the solubility of polypropene wax and reduce the viscosity of the solution.A similar effect can be achieved by adding some ethanol to the sodium sulphate aqueous solution.
A solvent commonly used in any of several fiber-forming polymers
Boiling poit of solvent(degree)
Minimum temperature of polymer dissolves(degree)
DMAC ethylence carbonate
Acetone plus carbon disulfide(1:1)