VINYLIDENE FLUORIDE POLYMER POWDER AND VINYLIDENE FLUORIDE POLYMER SOLUTION

摘要

Provided are a vinylidene fluoride polymer powder which is well soluble in an aprotic polar solvent, and a vinylidene fluoride polymer solution prepared from both the powder and an aprotic polar solvent. The vinylidene fluoride polymer powder has an NMP penetration of 12 to 100% as determined by a specific NMP penetration test. The NMP penetration test comprises: forming a lower sea sand layer in a glass tube which has an inside diameter of 8mm and in which a lower section packed with absorbent cotton has been formed; introducing 1g of the vinylidene fluoride polymer powder onto the surface of the lower sea sand layer to form a vinylidene fluoride polymer powder layer; forming an upper sea sand layer on the surface of the powder layer; pouring 5mL of methylene blue-dyed NMP on the surface of the upper sea sand layer; determining, 3 minutes after the pouring, the penetration depth of NMP into the vinylidene fluoride polymer powder layer and the thickness of the vinylidene fluoride polymer powder layer; and calculating the NMP penetration of the powder by dividing the penetration depth by the thickness and multiplying the obtained value by 100.