First, the detection method of formaldehyde in board
The principle of formaldehyde detection by plate 1 and dryer method is to process the artificial plate into a test block of about 5cm× 15cm, and seal the edge with formaldehyde-free tape to eliminate the problem of large formaldehyde release around it. Put the test block into a dryer with a certain volume (generally 9 ~ 1 1L), put distilled water into the dryer and put it into the dryer. After the formaldehyde released by the board is absorbed by distilled water, the concentration of formaldehyde in the absorption solution is detected by acetylacetone spectrophotometry, and the degree of formaldehyde released by the board is measured by this result.
Detection of formaldehyde in plate 2. Although this detection method is different from the actual use of the board, it can roughly compare the formaldehyde emission of the board, and the method is simple to operate and the instruments used are not expensive, so this method has its use value and is more suitable for the formaldehyde emission detection of blockboard and plywood. In actual detection, there are many factors that affect the accuracy of formaldehyde emission measurement by dryer method, mainly including the influence of sample sizing uniformity, temperature, plate storage method and color development conditions. The influence of the former is mainly overcome by inspectors, who should sample in strict accordance with the sampling methods and rules stipulated in the standard. We mainly discuss the latter factors.
Determination of formaldehyde in board 3. Among the factors affecting the determination of formaldehyde emission by dryer method, temperature has a great influence on the result. With the increase of collection temperature, the absorbance value of the collected liquid gradually increases after color development, especially when the temperature is above 30℃, the cured urea-formaldehyde resin will release formaldehyde, and the decomposition strength will increase with the increase of treatment temperature. Some people have done related experiments, and the test results increase by 10% for every increase in temperature. Therefore, it is necessary to establish a constant temperature laboratory to ensure the spatial uniformity of environmental conditions. The influence of color development conditions is mainly manifested in the color development time.
According to the standard method, after the sample is placed in the dryer for 24 hours, the solution to be tested should be moved to a triangular flask, and acetylacetone and ammonium acetate solution should be added to develop color in a water bath at (40 2℃). It can be seen from the results of measuring the absorbance of the chromogenic solution that the absorbance value is relatively stable after 15min and will not change with the time, so the chromogenic time should be controlled at 65438+. At the same time, we measured the change of absorbance of the chromogenic solution with storage time at room temperature. According to the determination results, the absorbance decreases with the increase of time, and it is generally 1 after color development.
What harm does formaldehyde in board do to people?
1, indoor formaldehyde exceeding the standard induces blood diseases in children.
Medical research has proved that excessive indoor formaldehyde has become the main cause of leukemia. Harbin Institute of Hematology and Oncology treated 1500 children with hematological diseases last year. Among them, leukemia patients are as high as 80%, mostly 4-year-old children. Why do children become a high-risk group of leukemia at present? Ma Jun, director of the institute, said that in addition to the internal causes of children's fragile immune function, harmful gases such as formaldehyde emitted by interior decoration materials are also one of the "killers".
2. Excessive indoor formaldehyde increases the incidence of asthma in children.
It can be seen from the investigation of asthma caused by indoor formaldehyde exceeding the standard by American experts that asthma accounts for 12.4 of the total population in the United States. This disease affects children of all ages, and 65% children suffer from asthma in different degrees. According to the World Health Organization, 654.38 million people worldwide die of asthma every year because of indoor air pollution, of which 35% are children. According to statistics, the prevalence rate of asthma in children in China is 2-5%, and the prevalence rate of children aged 1-5 is as high as 85%! Formaldehyde has become the main cause of asthma in children.
3. Indoor formaldehyde exceeds the standard, which greatly reduces children's intelligence.
200 1 British investment150,000 pounds "global environmental change" research group, after summarizing the research reports of scientists from various countries and conducting a lot of investigation and analysis, announced a shocking conclusion: environmental pollution has greatly reduced the intelligence of human beings, especially children! Dr Williams from the College of Education, University of London, who participated in the study, said: "This result exceeds people's previous estimates. The human brain is being damaged by human behavior. " Therefore, no matter from children's physical or intellectual development, the harm of indoor environmental pollution to children can not be ignored.
In order to have a comfortable and healthy living environment, many factors need to be considered. The specific detection method of formaldehyde board I mentioned can be referred to. In this way, the whole family will live a very healthy and happy life after the exam. You must remember the products of big brands when choosing materials.