Pigments are an indispensable element in painting and other art forms, and the quality and performance of pigments directly affect their application effect. Among them, the paraffin resistance of pigments is a particularly important indicator. This article will introduce in detail the method and significance of measuring the paraffin resistance of pigments.
Definition of paraffin resistance of pigments
Paraffin resistance can be defined as the ability of a pigment slurry to resist the staining of paraffin produced by the dissolution of paraffin in molten paraffin. In other words, it is an indicator used to describe the ability of a pigment to maintain its color and integrity in a paraffin environment. This property is mainly expressed in terms of staining series and is suitable for performance testing of most organic pigments.
importance
In some industrial applications, such as the production of certain special printing or packaging materials, pigments may come into contact with paraffin wax. If the pigment is poorly tolerant of paraffin wax, it may dissolve in the paraffin wax, causing a lighter or discolored color. This not only affects the appearance of the product, but also may have an adverse effect on its performance.
Determination of paraffin resistance
3.1 Required instruments and materials
In order to perform the determination of paraffin resistance, we require the following instruments and materials:
Pictorial printing paper shall comply with the standards of QB 2249-1996.
Balance, sensitivity 0.001 g and 0.2 g.
1 mL capacity syringe.
Adjusting knife for preparing ink pulp.
Beaker with a capacity of 50mL.
Electric thermostatic Water Bath
Gray sample card for evaluating staining according to GB 251-1995 standard.
Toner and drying oil.
No. 58 paraffin wax shall comply with the provisions of GB254-75.
3.2 Determination steps
Preparation of sample paper: First, mix the toner and drying oil in a ratio of 85:15, and then grind it into a pulp. The pulp is applied to the pictorial printing paper to form a uniform ink strip, and it is allowed to dry naturally.
Soaking wax: Take 20g of paraffin wax and heat it to 80 ℃, then immerse the prepared sample paper in the molten paraffin wax for 5 minutes, remove it and let it cool.
Blank test: Conduct a controlled experiment, using only blank strips of paper for wax dipping.
Evaluation of staining series: Under natural light, visually evaluate the degree of staining on the ink-free part of the sample paper compared with the gray sample card used for staining.
Result interpretation
According to the results of the measurement, the paraffin resistance can be divided into 5 grades, of which 5 is the best and 1 is the worst. In addition, there are representations between the two grades, such as grade 45, grade 34, etc.
summarize
The paraffin resistance of a pigment is one of the key factors that determine its performance in a specific application. Through the above determination method, we can know the stability of a pigment in a paraffin environment with certainty, thus providing a scientific basis for its selection in practical applications.
