Packaging and storage
Preserve in tight containers, at a temperature not exceeding 25
for Type A, and not exceeding 30
for Type B. Protect from freezing.
Label it to state whether it is Type A or Type B. Label it to indicate the name and quantity of any added antimicrobial preservative or alkalizing agent.
Use a viscosimeter equipped with a spindle having a cylinder 1.88 cm in diameter and 6.51 cm high attached to a shaft 0.32 cm in diameter. The distance from the top of the cylinder to the lower tip of the shaft is 0.75 cm, and the immersion depth is 8.15 cm. Adjust the temperature to 20 ± 0.10
. With the spindle rotating at 30 rpm, immediately record the scale reading. Multiply the scale reading by the constant for the viscosimeter spindle and speed employed, to obtain the viscosity in centipoises. The viscosity is not more than 100 centipoises.
Residue on ignition 281
Using mild heating conditions (e.g., steam bath, sand bath, etc.) to avoid loss of material, evaporate the dispersion to dryness prior to ignition: not more than 0.5% of residue is obtained, calculated on the undried dispersion basis.
Limit of monomers
Proceed as directed in the test for Limit of monomers
under Ammonio Methacrylate Copolymer:
not more than 0.002% of methyl methacrylate and not more than 0.008% of ethyl acrylate are found.
Accurately weigh a stainless steel sieve having 125-µm openings, and filter 100 g of Dispersion through it. Wash the sieve with distilled water until a clear filtrate is obtained, and dry the sieve to constant weight at 105
: the weight of the residue does not exceed 1000 mg (1%).
Dry under vacuum 2 g of Ammonio Methacrylate Copolymer Dispersion Type A, or 4 g of Ammonio Methacrylate Copolymer Dispersion Type B, at 90
for 30 minutes. Dissolve in 75 mL of glacial acetic acid at about 50
, within about 30 minutes. After the solution has cooled down, add 25 mL of 0.6% cupric acetate solution in glacial acetic acid, and titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Perform a blank titration, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 20.772 mg of ammonio methacrylate (C9