Water Solubility

Procedure for dissolving Nichigo G-Polymer™

[Test conditions]
After dispersing Nichigo G-Polymer™ or fully saponified PVOH in water while stirring, heat the solution until dissolution.

Temperature: Raise from 20°C to 85°C (1°C/min)
Concentration: 10%

Note that the dissolution time varies depending on the dispersion state of Nichigo G-Polymer™ and stirring conditions.

[Test conditions]
After dispersing Nichigo G-Polymer™ in water while stirring, heat the solution to the dissolution temperature. After stirring the solution for a specified time period, cool it to check the dissolution state.

Test concentration: 5%

Nichigo G-Polymer™ does not dissolve in most organic solvents.
This polymer exhibits solubility or partial solubility in organic solvents including ethylene glycol, triethylene glycol, glycerin, acetamide, dimethylacetamide and dimethyl sulfoxide.
It also dissolves in mixed solutions of water and lower alcohol.

Sample: Nichigo G-Polymer™ BVE8049Q film

Test temperature: 23°C

Nichigo G-Polymer™: fully saponified

[Test conditions]
Gradually add ethanol to resin aqueous solution while stirring and evaluate the amount added until precipitation (white turbidity) occurs.

Due to its molecular structure, Nichigo G-Polymer™ has excellent low foaming characteristics in aqueous solutions.
Aqueous solutions with excellent workability can be achieved without adding antifoaming agent.

Right: Nichigo G-Polymer™ (fully saponified)
Left: PVOH (fully saponified)

[Test method]
Add a 1% aqueous solution (200 mL) into a 1L graduated cylinder, blow in 300 cc/min of air through a sparger, and observe the height of the foam over time.

Aqueous solutions of Nichigo G-Polymer™ demonstrate excellent viscosity stability when stored at low temperatures.
By controlling crystallinity, the viscosity of the aqueous solution can also be controlled.





Nichigo G-Polymer™: fully saponified

10% aqueous solution stored at 5°C, viscosity measurement: Brookfield viscometer, 10 rpm

Nichigo G-Polymer™ aqueous solution exhibits resistance to the occurrence of flow abnormalities even under high shear conditions.
Therefore, application to high-speed coating and other purposes is expected.



Partially saponified PVOH, degree of saponification: 88 mol%

[Measurement]
Capillary rheometer, 7.5% aqueous solution

Nichigo G-Polymer™ is stable and resists changes in viscosity even in highly concentrated alkaline aqueous solutions.



[Test method]
Mix 12% resin aqueous solution and 20% NaOH aqueous solution 1:1.
Observe the solution state after leaving at 23°C for 3 days.

Dissolution state when dissolving each resin in 10% NaOH aqueous solution

[Conditions]
Polymer concentration: 6%
Dissolution condition : 90°C, 1 hr
Storage temperature : 40°C

Viscosity was measured at different pHs when stored at 5°C and at 23°C.
Fully saponified PVOH stored at 5°C formed a gel in one day. In contrast, the viscosity of Nichigo G-Polymer™ remained stable regardless of pH.

Viscosity stability of aqueous solutions over time

[Test method]
Measured the viscosity of a 7% aqueous solution at a pH adjusted to 3.0 with 10% acetic acid aqueous solution and to 8.0 and 13.0 with 10% NaOH aqueous solution, after storage at 5°C and 25°C for one month

Nichigo G-Polymer™ also dissolves in aqueous solutions containing a large amount of lower alcohol.

Nichigo G-Polymer™ aqueous solution demonstrates high surface tension compared to PVOH.

Addition of a crosslinker

While Nichigo G-Polymer™ is a resin with outstanding water solubility, water resistance can be achieved by using it with a crosslinker.
Nichigo G-Polymer™ also has high crosslinking performance compared to PVOH.