Solid content analysis of water-based and solvent-based coatings

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automated measurement %NVM - compared to the ASTM method in the United States
analysis of coating solid content (non-volatile percentage content or %NVM) is required for a variety of reasons. Suppliers in the industry often sell products based on solid content. Accurate determination of solid content is critical to understanding their results and customer satisfaction.
U.S. Environmental Protection Agency (EPA) regulations require volatile organic compounds (
). VOCs
) and should comply with regulatory requirements
. The determination of volatile organic compounds includes the determination of the solid content of the product, but the solid content is only part of the VOC determination step. Determining water content using Carl Fissew titration or gas chromatography is also necessary to calculate VOC.
coating professionals regard the solid content as an important indicator of coating quality. The thickness or viscosity itself is not a barometer of the quality of the coating, as it only indicates the amount of thickener used in the formulation (flow aid). To diagnose the problem, a solid content analysis is also performed. For example, a batch with a low viscosity reading may contain too much water or solvent, or it may be inaccurate in the amount of thickener. Solid content testing will solve the problem.
solid content testing is a standard method of oven baking in a laboratory environment using the American Society for Material Testing (ASTM). This requires the testing to be transferred to the production area for quick processing. Because quality control (QC) laboratories require many complex analyses, the production process requires a relatively simple method of measuring conventional solid content. Ideally, a solid content analyzer should be included in the production facility, which has the advantage of being fast and easy to operate, with the same accuracy as the results obtained in the laboratory using traditional ASTM methods.
Mark 3
water analyzer, which can be used on the production floor, meets this accuracy requirement and can be designed to be tested once with a simple one-click operation. The aim of the industry is to shorten the time period required for conventional solid content determination methods. The traditional method requires 60 minutes of baking in an oven from 105 to 110 degrees C and requires weighing the sample tray and sample before and after baking (ASTM standard numbers: D2369 and D2926-80). Because traditional test methods take time, production batches must take time to wait for the results of the analysis before they can be further produced or shipped.
coating manufacturers are looking for ways to perform solid content analysis in minutes so that batch adjustments or treatments can be completed in the shortest possible time. Mark 3 solid content analyzers typically take 3 to 10 minutes to complete the test, depending on the volatile or moisture content and viscosity of the material.
how the analyzer works
using a laptop, the solid content analyzer is essentially an automated oven that tracks the weight change rate of the sample internally. The instrument automatically peels the empty sample tray and filter paper and reminds the user to add the ideal weight sample to the plate. When the cover is closed, the instrument will obtain the starting weight of the sample and begin testing.
the instrument will complete the test once the pre-set weight change (or decrease) rate meets the requirements. Upon completion of the experiment, the instrument will give warning signs and print results at the end of the test, store data inside the instrument, and transmit the data to the company's computer or laboratory information management system (LIMS) in real time.
each test instrument will guide the user to add a sample of a consistent weight. This is called ideal weight. When the user has added the sample and covered it, the instrument is heated to a pre-set temperature and kept at that temperature, which can be ± up and down by less than 1 degree C. The temperature range can be set between room temperature and 210 degrees C. Each resin or coating can be programmed and stored in memory by name. Allows you to save up to 300 complete documents of different substances, neither printouts nor internal statistics and select external downloads.
parameter settings
program variables in each material set by the solid content analyzer include: test temperature, test endpoint setting and ideal sample weight. Sedulis develops different programs for different materials for our customers. This was done by the Applied Laboratory of Sedulis. Compare the test results of the Mark 3 analyzer with 2 results obtained by ASTM or other reference methods. The latter is usually a blowing oven or a vacuum oven. Compare the test values of the Mark 3 analyzer with the reference values to confirm the accuracy and accuracy of the analyzer. Compare the average of the repeat test results with the reference values for accuracy, which is determined by the standard deviation of the Mark 3 analyzer repeat test (Table 1).
1: Results obtained using conv current or vacuum ovens and Mark 3 moisture analyzers.。 Material typeoven reference (%S) Mark 3
results (%S)test time (minutes)standard deviation DuPont titanium white slurry 76.09 76.11 3.0 0.072Conos
Titanium White 76.78 76.76 3.2 0.054 EPS
acrylic 49.14 49.09 12.2

0.101 。 Fluid modifiers 20.64 20.75 10.3 0.040acrylic 54.88 54.88 6.4 0.107 subs Polyurethane 77.89 77.94 13.3 .119 solvent-based coatings 66.48 66.40 5.8 0.122 latex 76.73 76.70 3.1 0.082 Road sign paint 79.26 79.29 6.8 0.068 Nitroculose Solution 01.52 01.49 5.5 0.090
temperature
The instrument heats up rapidly to a pre-set temperature and remains within the set temperature ±1 degrees C during the test. The set temperature should volatile the solvent and moisture, but will not damage the sample and match the reference results.
the test end point setting
function determines when the test is completed. The percentage of time and initial weight of the sample is two variables in the endpoint settings that are used by the instrument to set the program for a given material. In "Actual" mode, the rate of change in the program (initial weight percentage) is set in time. The weight change rate measured by the instrument uses one-third of the set time. For example, if the instrument is set to a one-minute change of 0.10%, the instrument measures every 20 seconds in the most recent minute whether the rate of change has reached 0.10% or less. If the change rate of 0.10% or less is reached, the instrument will end the test. If the rate of change is greater than 0.10%, the instrument will measure the rate of change every 20 seconds for the next minute. This ensures that the sample will be heated to constant weight (Figure 1).
in Calculation mode, the instrument uses the time and percentage functions in a different way. Internally, when calculation mode is enabled, macros that predict the test's approach line or test end point are activated. In increments of a set time or one-third of the window, the instrument records the calculated value. When the last three calculations are consistent with the pre-set percentage range, the instrument completes the test based on the average of the last three predictions. In computational mode, the drying characteristics of the sample must be represented by exponential attenuation, which is critical. Since the calculation mode can predict the remaining moisture content according to the curve of a given sample, the test time can be greatly shortened. In addition, since the instrument averages the last 3 calculations, the results are usually more consistent, which will improve the standard deviation (Figure 2).
, however, the volatiles of many coatings and adhesives flash dry at the beginning of the trial. For these samples, it is recommended to use the "injection" mode in the actual mode. In order to accurately obtain the initial weight of these volatile samples, Sedulis developed an "injection method
on
mark
3
solid content analyzer. Using this method, the instrument guides the user to weigh the weight before and after the syringe fills the sample. The initial weight obtained by the instrument is determined by the difference in weight of the syringe. Manual calculations are not required for the operator (Figure 3).
weight: This
requires the user to add a consistent amount of samples for each and each test. Between 90% and 109% of the set ideal weight, the instrument will send an auditory warning signal and indicate "close the door". A typical sample size range is between 1 and 3 grams. However, the specific ideal sample weight should be determined depending on the type of sample to be tested.
overview
all businesses are currently using quality standards and are facing increasing workloads. The development of instrumentation that provides accurate data and significantly reduces analysis time is both expected and essential. This is especially important when test data determines whether production batches can be shipped on time or whether they need to be processed.
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