Method for detecting formaldehyde emission of artificial board

Abstract

The invention discloses a method for detecting formaldehyde emission of an artificial board, which comprises the following steps of: performing edge sealing treatment on at least part of the side surface of a cut test piece by using a formaldehyde-free aluminum foil adhesive tape, and reserving the upper surface and the lower surface of the test piece, so that the balance time of the test piece can be shortened from seven days in the prior art to 24 hours; therefore, the balance treatment time of the test piece can be greatly shortened, the detection time of the formaldehyde emission of the whole artificial board can be shortened, and the detection of the formaldehyde emission is quicker and more efficient. Besides, compared with a dryer method in the prior art, the method for detecting the formaldehyde emission of the artificial board in the embodiment of the invention can also obtain a detection result which is better in correlation with a standard 1m < 3 > climate box method, and the accuracy and reliability of detection are improved.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and specifically to a method for detecting formaldehyde emission from engineered wood products. Background Technology

[0002] During the production process of engineered wood products, it is usually necessary to test the formaldehyde emission level. The main methods for measuring formaldehyde emission are 1m... 3 Between the climate chamber method and the desiccator method, the climate chamber method, which uses temperature, relative humidity, loading, air exchange rate, and air velocity at the sample surface as influencing factors, most closely approximates the actual usage conditions of engineered wood products and is therefore a more scientific testing method. Thus, the climate chamber method is generally used for testing formaldehyde emissions from engineered wood products. The desiccator method is only used for production control in enterprises, and the formaldehyde emission measured using the desiccator method needs to be compared with the standard 1m³. 3 When comparing the climate chamber method, the higher the correlation between the two methods, the more accurate the formaldehyde release detected by the desiccator method is.

[0003] However, the climate chamber method has a long testing time, requiring at least 18 days and up to 28 days, which is not conducive to production quality control for enterprises. Compared with the climate chamber method, the desiccator method has the advantages of low cost, fast speed, simple operation, and batch operation, making it an important means for enterprises to control production. However, in the current desiccator method, when equilibrating artificial board samples, in order to achieve constant sample quality, the samples usually need to be placed under conditions of relative humidity (65±5)% and temperature (20±2)℃ for seven days. This sample equilibration time not only prolongs the testing time of the desiccator method but also reduces its testing efficiency. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for detecting formaldehyde emission from engineered wood products, which can shorten the specimen equilibration treatment time and improve the accuracy of the detection results compared to the standard 1m. 3 Correlation between climate chamber methods.

[0005] A method for detecting formaldehyde emission from engineered wood products according to a first aspect of the present invention includes the following steps:

[0006] S1: Specimen preparation: The sides of the cut specimen are sealed with formaldehyde-free aluminum foil tape at least partially, while retaining the upper and lower surfaces of the specimen.

[0007] S2: Specimen balancing treatment: After sealing, the specimens are placed for 24 hours under conditions of relative humidity (65±5)% and temperature (20±2)℃.

[0008] S3: Formaldehyde collection: Place a crystallizing dish containing (300±1) mL of distilled water into a desiccator, place a support net on the crystallizing dish, place the test specimen on the support net, seal the desiccator, and place the desiccator at (20±0.5)℃ for 24h±10min. The distilled water in the crystallizing dish can absorb the formaldehyde released from the test specimen and obtain the test solution.

[0009] S4: Formaldehyde release determination: Take out the crystallization dish and measure the formaldehyde concentration in the test solution inside the crystallization dish.

[0010] The method for detecting formaldehyde emission from engineered wood products according to embodiments of the present invention has at least the following beneficial effects:

[0011] In the formaldehyde emission detection method for engineered wood products of this invention, the test specimen is edge-sealed by using formaldehyde-free aluminum foil tape to seal at least part of the sides of the cut specimen, while retaining the upper and lower surfaces. This seals the sides of the specimen, allowing formaldehyde to be released only from the exposed surfaces. This not only simulates the exposed conditions of the specimen in actual use but also ensures that the specimen reaches a constant mass within 24 hours. Therefore, compared to the prior art, this invention, by sealing the specimen, reduces the equilibration time from seven days to 24 hours, significantly shortening the equilibration time and consequently the overall formaldehyde emission detection time, making the detection faster and more efficient. Furthermore, sealing the sides also seals the adhesive, reducing instability in test results caused by differences in the number of adhesive layers or the amount of adhesive applied to specimens of the same thickness. Compared to the existing dryer method, the formaldehyde emission detection method for engineered wood products of this invention can also obtain results comparable to the standard 1m. 3 The climate chamber method yields better correlation results, improving the accuracy and reliability of the detection.

[0012] According to some embodiments of the present invention, in step S1, the dimensions of the specimen are: length L = (225±1) mm and width b = (100±1) mm.

[0013] According to some embodiments of the present invention, in step S1, the size of the specimen is: or the sum of the areas of the upper and lower surfaces of the specimen is 450 cm². 2 .

[0014] According to some embodiments of the present invention, in step S1, when the test piece is a floor, the test piece includes two floor test samples, the upper surface of one floor test sample is attached to the lower surface of the other floor test sample, and the sides of the two floor test samples are completely sealed and bonded with formaldehyde-free aluminum foil tape.

[0015] According to some embodiments of the present invention, in step S1, when the specimen is plywood, the specimen includes a plywood test sample, the side of the plywood test sample is sealed with formaldehyde-free aluminum foil tape, and 68mm is left unsealed in the length or width direction of the specimen.

[0016] According to some embodiments of the present invention, in step S2, when there are multiple specimens, the interval between two adjacent specimens is at least 25 mm.

[0017] According to some embodiments of the present invention, in step S3, one of the test specimens is placed inside one of the dryers.

[0018] According to some embodiments of the present invention, in step S3, the desiccant is placed in a constant temperature test chamber, the temperature inside the constant temperature test chamber is (20±0.5)℃, and a temperature and humidity recorder is installed inside the constant temperature test chamber. The temperature and humidity are continuously monitored for 24 hours by the temperature and humidity recorder, and the temperature and humidity inside the constant temperature test chamber are recorded every 30 minutes during this period.

[0019] According to some embodiments of the present invention, step S4 includes:

[0020] S4.1: Take 10 mL of acetylacetone solution, 10 mL of ammonium acetate solution, and 10 mL of the test solution according to standard operating procedures and place them in a 50 mL Erlenmeyer flask with a stopper. Stopper the flask and mix the acetylacetone solution, the ammonium acetate solution, and the test solution to form a mixed solution.

[0021] S4.2: Place the mixed solution in a constant temperature water bath at (60±1)℃ and heat for 10 min, then store the heated solution in the dark for 1 h;

[0022] S4.3: Using a spectrophotometer, at a wavelength of 412 nm, with distilled water as a control solution, measure the absorbance Ad of the mixed solution and the absorbance Ab of the control solution, and calculate the formaldehyde concentration of the test solution based on the absorbance Ad and the absorbance Ab.

[0023] According to some embodiments of the present invention, in step S4.3, before transferring the mixed solution for formaldehyde concentration determination, the mixed solution can be placed at a temperature of 0℃-5℃ for 0-30h.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 This is a schematic diagram illustrating the correlation between the formaldehyde emission detection method for engineered wood products according to an embodiment of the present invention and the standard 1m³ climate chamber method.

[0027] Figure 2 This diagram illustrates the correlation between the existing dryer method and the standard 1m³ climate chamber method. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0029] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0030] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0031] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0032] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0033] An embodiment of the present invention provides a method for detecting formaldehyde emission from engineered wood products, which specifically includes the following steps:

[0034] S1: Specimen preparation: Use formaldehyde-free aluminum foil tape to seal at least part of the sides of the cut specimen, and retain the upper and lower surfaces of the specimen.

[0035] S2: Specimen balancing treatment: After sealing, the specimens are placed for 24 hours under conditions of relative humidity (65±5)% and temperature (20±2)℃.

[0036] S3: Formaldehyde collection: Place a crystallizing dish containing (300±1)mL of distilled water into a desiccator, place a support net on the crystallizing dish, place the test specimen on the support net, seal the desiccator, and place the desiccator at (20±0.5)℃ for 24h±10min. The distilled water in the crystallizing dish can absorb the formaldehyde released from the test specimen and obtain the test solution.

[0037] S4: Formaldehyde release determination. Take out the crystallization dish and measure the formaldehyde concentration in the solution to be tested in the crystallization dish.

[0038] In the formaldehyde emission detection method for engineered wood products of this invention, an edge-sealing treatment is added to the specimen before the equilibration process. This involves sealing the sides of the cut specimen with formaldehyde-free aluminum foil tape while retaining the top and bottom surfaces. This seals the sides, allowing formaldehyde to be released only from the exposed surfaces. This simulates the exposed state of the specimen in actual use and ensures the specimen reaches a constant mass within 24 hours. Therefore, compared to existing technologies, this invention reduces the equilibration time from seven days to 24 hours by sealing the specimen, significantly shortening the equilibration process and consequently the overall formaldehyde emission detection time, making the detection faster and more efficient. Furthermore, sealing the sides also seals the adhesive, reducing instability in test results caused by differences in the number of adhesive layers or the amount of adhesive applied to specimens of the same thickness.

[0039] Referring to the table below, which compares the formaldehyde emission detection method for engineered wood products according to the present invention, the existing desiccator method, and the standard 1m³ climate chamber method with experimental data, the table also includes relevant data. Figure 1 and Figure 2 , Figure 1 The formaldehyde emission detection method and standard for engineered wood products according to the embodiments of the present invention obtained in the table below are 1m 3 A diagram illustrating the correlation between climate chamber methods. Figure 2 Based on the existing dryer method and standard 1m obtained from the table below 3 A diagram illustrating the correlation between climate chamber methods. See the table below and... Figure 1 , Figure 2 It can be seen that, compared with the existing dryer method, the formaldehyde emission detection method for engineered wood products in this embodiment of the invention yields detection results that are consistent with the standard 1m. 3 The correlation between climate chamber methods is higher, meaning that the formaldehyde emission detection method for engineered wood products in this embodiment of the invention can not only significantly shorten the detection time and improve the detection efficiency, but also obtain results consistent with the standard 1m. 3 The climate chamber method yields better correlation results, improving the accuracy and reliability of the detection.

[0040]

[0041] In some embodiments, in step S1, the dimensions of the specimen are: length L = (225±1) mm and width b = (100±1) mm; this facilitates sealing and testing of the specimen.

[0042] It is understood that, in some embodiments, the dimensions of the specimen may also be set such that the sum of the areas of the upper and lower surfaces of the specimen is 450 cm². 2 This not only facilitates the sealing and testing of specimens, but also enhances the flexibility of specimen preparation during cutting.

[0043] In some embodiments, in step S1, when the specimen is flooring, the specimen includes two flooring test samples. The upper surface of one flooring test sample is attached to the lower surface of the other flooring test sample, and the sides of both flooring test samples are completely sealed and bonded with formaldehyde-free aluminum foil tape. This allows the edge sealing treatment of the specimen to be close to the flooring specimen treatment method of the standard 1m³ climate chamber method, which is beneficial to improve the correlation between the formaldehyde emission detection method of artificial boards in this embodiment of the invention and the standard 1m³ climate chamber method. In this way, detection results with better correlation with the standard 1m³ climate chamber method can be obtained, thereby improving the accuracy and reliability of the detection.

[0044] Understandably, when the test specimen is a floor, the specimen consists of two floor test samples. The upper surface of one floor test sample is attached to the lower surface of the other floor test sample. Specifically, the side surface of the two floor test samples that are attached can be the bottom surface of the floor test sample in actual application. This allows the bottom surfaces of the two floor test samples to be attached back to back, which can more realistically simulate the scenario where the top surface of the floor test sample is exposed in actual application. This results in test results with better correlation to the standard 1m3 climate chamber method, improving the accuracy and reliability of the test.

[0045] In some embodiments, in step S1, when the specimen is plywood, the specimen includes a plywood test sample. The sides of the plywood test sample are sealed with formaldehyde-free aluminum foil tape, and 68mm of the specimen is left unsealed in the length or width direction. This allows the edge sealing treatment of the specimen to be closely similar to the plywood specimen treatment method of the standard 1m³ climate chamber method, which is beneficial for improving the formaldehyde emission detection method of engineered wood products in this embodiment of the invention compared to the standard 1m³ climate chamber method. 3 The correlation between climate chamber methods can be improved, thus obtaining test results with better correlation to the standard 1m³ climate chamber method, thereby improving the accuracy and reliability of the test.

[0046] In some embodiments, in step S2, when there are multiple specimens, the interval between two adjacent specimens is at least 25 mm, which facilitates the free circulation of air on the surface of the specimens, speeds up the equilibrium time of the specimens, and enables the specimens to quickly reach a constant mass.

[0047] It is understood that the aforementioned test specimen can be a floor test specimen containing two floor test samples or a plywood test specimen containing one plywood test sample. The present invention does not specifically limit this, as long as the distance between two adjacent test specimens is set to at least 25mm during the balancing process to facilitate air circulation on the surface of the test specimen.

[0048] In some embodiments, in step S3, a test specimen is placed in a desiccator, which facilitates the subsequent calculation of the formaldehyde concentration in the test solution and also helps to improve the accuracy and reliability of the detection.

[0049] In some embodiments, in step S3, the dryer is placed in a constant temperature test chamber with a temperature of (20±0.5)℃. A temperature and humidity recorder is installed inside the test chamber to continuously monitor the temperature and humidity for 24 hours, recording the temperature and humidity every 30 minutes. This provides a constant temperature environment of (20±0.5)℃ for the dryer and facilitates the detection and control of the temperature inside the test chamber, thus improving the accuracy and reliability of the detection.

[0050] In some embodiments, step S4 includes:

[0051] S4.1: Take 10 mL of acetylacetone solution, 10 mL of ammonium acetate solution, and 10 mL of the test solution according to the standard operating procedure and place them in a 50 mL Erlenmeyer flask with a stopper. Stopper the flask and mix the acetylacetone solution, ammonium acetate solution, and test solution to form a mixed solution.

[0052] S4.2: Place the mixed solution in a constant temperature water bath at (60±1)℃ and heat for 10 min, then store the heated solution in the dark for 1 h.

[0053] S4.3: Using a spectrophotometer, at a wavelength of 412 nm, with distilled water as a control solution, measure the absorbance Ad of the mixed solution and the absorbance Ab of the control solution. Calculate the formaldehyde concentration of the test solution based on the absorbance Ad and absorbance Ab.

[0054] By following the steps described above, it is convenient to calculate the formaldehyde concentration of the test solution and accurately obtain the formaldehyde release from the sample, which helps improve the accuracy and reliability of the detection. It is understood that the mixed solution should be thoroughly mixed before transferring it for formaldehyde determination.

[0055] In some embodiments, in step S4.3, before transferring the mixed solution for formaldehyde concentration determination, the mixed solution can be placed at a temperature of 0℃-5℃ for 0-30 hours. Therefore, if the mixed solution cannot be tested immediately after preparation, it can be stored at 0℃-5℃ for 0-30 hours, i.e., no more than 30 hours. This reduces the impact of prolonged storage on subsequent test results, thereby improving the accuracy and reliability of subsequent tests.

[0056] In some embodiments, in step S4.3, a standard curve is plotted according to standard operation, and the slope f of the standard curve is obtained. The formula for calculating the formaldehyde concentration c of the test solution is c = f × (Ad - Ab). This formula can accurately calculate the formaldehyde concentration of the test solution, making the detection results obtained by the formaldehyde emission detection method of artificial board of the present invention more correlated with the standard 1m3 climate chamber method, which is beneficial to improving the accuracy and reliability of the detection.

[0057] Understandably, following standard operating procedures, a standard curve is plotted, and its slope f is obtained. Specifically, 1.5 mL of formaldehyde standard solution (10.0 mg / mL) in water is transferred to a 20 mL white volumetric flask using a 2 mL graduated pipette, and then diluted to the mark with distilled water to obtain a formaldehyde standard solution with a concentration of 0.75 mg / mL. Then, 2 mL of this solution is transferred to a 10 mL volumetric flask using a 2 mL single-mark pipette, and diluted to the mark with distilled water to obtain a formaldehyde standard solution with a concentration of 150 mg / L. Finally, 5 mL of this solution is transferred to a 250 mL volumetric flask using a 5 mL single-mark pipette, and diluted to the mark with distilled water to obtain a formaldehyde calibration solution with a concentration of 3 mg / L. 0, 5, 10, 20, 50, and 100 mL of this formaldehyde calibration solution are then transferred to 100 mL volumetric flasks using single-mark pipettes, and diluted to the mark with distilled water. Formaldehyde standard solutions with concentrations of 0.00, 0.15, 0.30, 0.60, 1.50, and 3.00 mg / L were obtained. Standard curves were plotted based on the absorbance of formaldehyde solutions of different concentrations (between 0 and 3 mg / L), and the slope f of the standard curves could then be obtained.

[0058] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for detecting formaldehyde emission from engineered wood products, characterized in that, Includes the following steps: S1: Specimen preparation: The sides of the cut specimen are sealed with formaldehyde-free aluminum foil tape at least partially, while retaining the upper and lower surfaces of the specimen. S2: Specimen balancing treatment: After sealing, the specimens are placed for 24 hours under conditions of relative humidity (65±5)% and temperature (20±2)℃. S3: Formaldehyde collection: Place a crystallizing dish containing (300±1) mL of distilled water into a desiccator, place a support net on the crystallizing dish, place the test specimen on the support net, seal the desiccator, and place the desiccator at (20±0.5)℃ for 24h±10min. The distilled water in the crystallizing dish can absorb the formaldehyde released from the test specimen and obtain the test solution. S4: Formaldehyde release determination: Take out the crystallization dish and measure the formaldehyde concentration in the test solution inside the crystallization dish.

2. The method for detecting formaldehyde emission from engineered wood products according to claim 1, characterized in that, In step S1, the dimensions of the specimen are: length L = (225±1) mm and width b = (100±1) mm.

3. The method for detecting formaldehyde emission from engineered wood products according to claim 1, characterized in that, In step S1, the sum of the areas of the upper and lower surfaces of the specimen is 450 cm². 2 .

4. The method for detecting formaldehyde emission from engineered wood products according to claim 2 or 3, characterized in that, In step S1, when the test specimen is flooring, the test specimen includes two flooring test samples. The upper surface of one flooring test sample is attached to the lower surface of the other flooring test sample, and the sides of the two flooring test samples are completely sealed and bonded with formaldehyde-free aluminum foil tape.

5. The method for detecting formaldehyde emission from engineered wood products according to claim 2 or 3, characterized in that, In step S1, when the specimen is plywood, the specimen includes a plywood test sample. The side of the plywood test sample is sealed with formaldehyde-free aluminum foil tape, and 68mm is left unsealed in the length or width direction of the specimen.

6. The method for detecting formaldehyde emission from engineered wood products according to claim 2 or 3, characterized in that, In step S2, when there are multiple specimens, the interval between two adjacent specimens is at least 25 mm.

7. The method for detecting formaldehyde emission from engineered wood products according to claim 2 or 3, characterized in that, In step S3, one of the test specimens is placed inside one of the dryers.

8. The method for detecting formaldehyde emission from engineered wood products according to claim 7, characterized in that, In step S3, the desiccant is placed in a constant temperature test chamber with a temperature of (20±0.5)℃. A temperature and humidity recorder is installed in the constant temperature test chamber to continuously monitor the temperature and humidity for 24 hours, recording the temperature and humidity inside the constant temperature test chamber every 30 minutes.

9. The method for detecting formaldehyde emission from engineered wood products according to claim 2 or 3, characterized in that, Step S4 includes: S4.1: Take 10 mL of acetylacetone solution, 10 mL of ammonium acetate solution, and 10 mL of the test solution according to standard operating procedures and place them in a 50 mL Erlenmeyer flask with a stopper. Stopper the flask and mix the acetylacetone solution, the ammonium acetate solution, and the test solution to form a mixed solution. S4.2: Place the mixed solution in a constant temperature water bath at (60±1)℃ and heat for 10 min, then store the heated solution in the dark for 1 h; S4.3: Using a spectrophotometer, at a wavelength of 412 nm, with distilled water as a control solution, measure the absorbance Ad of the mixed solution and the absorbance Ab of the control solution, and calculate the formaldehyde concentration of the test solution based on the absorbance Ad and the absorbance Ab.

10. The method for detecting formaldehyde emission from engineered wood products according to claim 8, characterized in that, In step S4.3, before transferring the mixed solution for formaldehyde concentration determination, the mixed solution can be placed at a temperature of 0℃-5℃ for 0-30h.

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