Test method for solids content of additives
Introduction
Solids content (solid content) is one of the common test indicators of printing and dyeing auxiliaries, which can usually reflect the effective content of the auxiliaries, on the one hand, can be used as a reference indicator for a variety of auxiliaries, but also as a batch of auxiliaries for comparison and inspection.
However, do not exclude that some auxiliaries manufacturers through bad means to increase the solid content of non-effective ingredients, the final test is still subject to the use of the effect.
A. Oven method
1, the principle: a certain quality of the specimen at a certain temperature under atmospheric pressure drying for a certain period of time, the percentage of the mass of the heated specimen and the mass of the heated specimen before the solids content.
2、Measurement step gathering
① Take three weighing bottles, dry in the oven at (105±2) ℃ for 1.5h, then cool down in the desiccator for 30min after weighing, and record as m1.
② Weigh 1~2g (accurate to 0.0001g) of the sample in the dried weighing bottle, and record as m.
③ gently turn to the weighing bottle, so that the specimen is evenly distributed in the bottom of the weighing bottle, weighing bottle cover slightly open, placed in the oven at (105±2) ℃, turn on the blower, dry for 3h, cover the bottle tightly, put it into the desiccator to cool for 30min, weigh, and record as m2.
3、Calculation of results
The solid content of the specimen in mass fraction X, the value is expressed in (%), calculated according to formula (1).
X = (m2-m1)/m × 100% (1)
Where.
m – the value of the mass of the specimen. The unit is grams (g).
m1 – the value of the mass of the specimen. Unit in grams (g).
m2 – the value of the mass of the weighing bottle and the specimen after drying. The unit is grams (g).
Take the arithmetic mean of the two parallel measurements, according to GB/T8170-2008 modified to 0.1% of the measurement results, the difference between the two parallel measurements is not more than 0.3%.
B. Brix meter method
1、Principle.
Using the refraction principle of the measured solution brix and its solid content is a certain proportional relationship, through the determination of the solution brix, according to a certain proportional coefficient can be converted to the solid content of the sample.
2. Determination procedure.
The test should be conducted at room temperature, and the sample should be equilibrated to room temperature before measurement.
① Clean the surface of the prism of the saccharimeter, add about 0.3mL of water on its surface, and adjust the zero according to the operating instructions of the saccharimeter.
② Discard the water on the saccharimeter, dry the prism, add about 0.3 mL of the sample drop by drop on its surface, and measure the sugar content of the sample in accordance with the operating instructions of the saccharimeter until the readings are stable for two times before and after, and then record as the sugar content A of the sample.
③ The solid content of the sample was converted according to the ratio coefficient n between solid content and brix obtained by data accumulation.
Note: Because this method is used to test the refractive principle, do not use it for the test of difficult to wash samples, otherwise it will contaminate the prism surface and the test is not accurate.
3、 Calculation of results
The solid content of the sample in terms of mass fraction X, the value is expressed in (%), according to the formula (2) calculation.
X = n × A ———- (2)
Where.
n – the conversion factor of solids and brix
A – Brix of the sample, %
