Comparison of determination methods of solubility

Comparison of solubility determination methods of ink raw materials

for many years, resin and binder manufacturers have used traditional titration to determine the solubility of products. This method can show the solid content at the beginning of distillation and the solubility difference of products when different oils or solvents are used

solubility plays an important role in binders and final ink products. This feature (index) will affect the adhesion, adhesion stability, plastic deformation value, flow rate, gloss and precipitation rate of products. In today's actual trend of reducing aromatic components in mineral fractions, the solubility of raw materials has become more important than ever

differences between different determination methods

both turbidity titration and traditional titration can provide numerical test results for technicians, and their results can be used for statistical analysis. The result of traditional titration is in milliliter or gram, while the result of turbidity method is in Celsius

the difference between the test part and the tester is very important for the correct value of solubility determination and the repeatability and reproducibility of the determination method. In the determination process of traditional titration method, there are many steps that will affect the final test results:

◆ weighing

◆ hot plate temperature

◆ heating and cooling slope

◆ stirring

◆ solvent addition rate and method

◆ determination of (titration) end point

turbidity law eliminates many variable factors associated with standard dilution method. The factors that will cause changes in the measurement process of this method are:

◆ weighing

◆ photocell

great importance is attached to the harmony between enterprises and society in the two different measurement processes; It is a cleaner production demonstration enterprise and garden unit in Shanghai; The different change data generated by the "technological innovation demonstration enterprise" recognized by the government will be shown later in this paper

why choose turbidity method

there are many different reasons for the laboratory to change the test method, and most of these reasons are because the laboratory believes that the results obtained by the new method can better show the performance of its products. The author believes that, The turbidity method is selected for the following reasons:

◆ shorten the test time

◆ it can produce more useful data (multiple data points/and a variety of solvents)

◆ reduce the changing factors in the test process

◆ the difference of the test part has little effect on the experimental results

◆ no cleaning

◆ the minimum amount of personnel training required

typical applications of turbidity method include raw material sample testing, in-process binder testing, new material characterization and identification, binder formula assistance and R & D

analysis of experimental results

the typical test of turbidity method is carried out under the content of 10% solid nonvolatile, which produces a single point result. This single point method is usually used for quality control and production testing. It is fast and can be used by technicians to determine the suitability of raw materials on site

when evaluating new materials or comparing different materials, it is best to use the multipoint method under different solid content. Through this method, technicians can intuitively understand the differences between materials and their solubility in different solvents according to the slope of the curve (see Fig. 1 and Fig. 3)

Figure 1: typical multipoint turbidity final closing 522 drop 1.88% method test curve

Figure 3: Multipoint test slope curve

solvents or greases used in the production of thick ink binder have a significant impact on the solubility of the resin system. Figure 2 shows the same resin in three different oils and two different solid contents. The test results can help the formulator select the grease that is most suitable to meet the requirements of adhesion, stability, dryness and fluidity

Figure 2: turbidity results measured in different solutions

Figure 2 shows the test results of the same resin in several standard solutions. This resin has the lowest solubility in Halterman 6/9 grease; Compared with other tested oils, the resin has the highest adhesion and adhesion stability in this kind of oil

when only a single point is tested, the solubility or turbidity of the material may be the same. In Figure 3, two different resins are tested in the same solvent. Results the same turbidity was obtained at 10% solid content; However, at 20% solid content, there is a 35 ° difference between the two resins in the same solvent. This indicates that there is a way to distinguish similar raw materials and provide other technical data according to quality control tests

binder formulation auxiliary

turbidity method can be used to determine the type and quantity of materials used in the binder formulation. There are countless varieties of binders today, which are used to control the solubility or rheology of products. Turbidity method can be used to determine the properties of different solvents, alkyd, grease and solubilizer, so as to produce a more stable final product, or control the solubility to a narrower range. Through it, different materials can be evaluated to determine which has the best solubility to the resin

it is well known that each material has different effects on solubility. The task of the technician is to find the material that performs best in the formula. Now with the turbidity method, the formulator has excellent data, instead of relying on experience or trained guessing as in the past

however, when testing resin mixtures, the measured curve will not always be a linear function. If the solubility of the resin is different, the result will show a curve, because the resin with the lowest solubility first precipitates from the solution. Turbidity is not the weight average of the resin mixture

reduce test differences

in today's world where statistical quality control and Six Sigma quality management systems are widely used, the reliability and repeatability of the test process and the reduction of differences caused by test locations and personnel are crucial

turbidity method meets this requirement. Compared with the standard titration method, the difference between the turbidity method and the standard titration method is relatively small. In addition, because there are too many variable factors mentioned earlier in the article, it is not easy to compare the test results obtained by standard dilution method in different places. Using the turbidity method, both the supplier and the customer can finally agree on the test results without repeating the test or sending samples

turbidity method is a reliable and simple method, which can shorten the test time, produce less test difference, and provide more useful data

bob cook is the deputy director of the linker and additives Department of lawter international, Inc. he has 32 years of experience in resin and ink linkers, and has worked in lawter international, Sun Chemical GPI, Hercules and other companies. Received a Bachelor of Science degree from Kent State University