Method for determining elemental composition in paint through X-ray fluorescence technology

Abstract

The invention provides a method for measuring elemental composition in paint through an X-ray fluorescence technology, which comprises the following steps: adding the paint to be measured into a cylindrical mold, drying, and forming a paint layer at the bottom of the mold; the thickness of the paint layer is not less than 1mm; uniformly mixing epoxy resin and a curing agent, adding the mixture into the mold, curing the epoxy resin, and firmly bonding the epoxy resin with the paint layer at the bottom; the mold is removed, and a test sample with the epoxy resin layer and the paint layer bonded is prepared; and testing by using an X-ray fluorescence spectrophotometer to obtain the element composition of the dry paint. According to the invention, sufficient paint is injected into the mold at one time, and is fixed by resin after being dried, so that the mold is formed at one time, has a stable structure and has the advantages of convenience in sample preparation, rapidness and accuracy in detection and the like. By means of the method, the composition of various heavy metal elements and other harmful elements in the paint sample can be obtained at a time, green and environment-friendly paint can be rapidly screened out, and good application value is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical and chemical measurement technology, and particularly relates to a method for determining the element composition in paint by X-ray fluorescence technology. Paint is a widely used chemical raw material in daily life. In order to make the paint have good use stability, different colors and textures, various additives need to be added to the paint. Therefore, the paint contains complex element composition, which may contain sulfur, arsenic and some heavy metal elements that are not conducive to human health. Some of these elements will gradually penetrate into the external environment over time. In recent years, people's demand for living quality is increasing, so the detection of element composition in paint has also attracted more attention.

[0002] The traditional element test method of paint mainly uses digestion method. The paint is dried and cut into pieces, and then acid or microwave digestion is directly added. Or the coating on the finished product is scraped off with a tool for digestion. The existing technology has many disadvantages for measuring the elements of paint, for example, some paints are difficult to digest with acid, which causes deviation in the measurement of some components. If microwave assisted digestion is used, it takes too long and is low in efficiency. Secondly, a large amount of gas is released during microwave digestion, which is easy to cause danger. Therefore, the traditional element test method of paint is complicated, low in efficiency, and cannot guarantee the accuracy of the final data. SUMMARY

[0003] In view of the many inconveniences of the digestion method for determining the element composition in paint, the present application provides a method for determining the element composition in paint by X-ray fluorescence technology. X-ray fluorescence test has the advantages of rapidness, accuracy and easy operation, and can determine the full element composition of the material at one time. However, X-ray fluorescence is usually used to determine the element composition of solid substances. In order to detect the element composition in liquid paint, the present application adds liquid paint to a circular mold to solidify it. In order to successfully remove the solidified paint, epoxy resin is added to the surface of the paint. After the resin is solidified, the paint can be bonded to the surface of the resin. Then the mold is removed, and a cylindrical sample with stable structure can be prepared for X-ray fluorescence element test.

[0004] The present application provides a method for measuring the element composition of paint by X-ray fluorescence technology, which has the characteristics of convenient sample preparation, rapidness and accuracy.

[0005] To achieve the above purpose, the method for determining the element composition in paint by X-ray fluorescence technology comprises the following steps: S1 adding the paint to be tested into a cylindrical mold, drying, and forming a paint layer at the bottom of the mold; the thickness of the paint layer is ≥1mm; S2 mix the epoxy resin and the curing agent uniformly, add into the mold to cover the paint layer, make the epoxy resin cure and firmly bond with the paint layer at the bottom; S3 remove the mold to prepare the test sample with the epoxy resin layer and the paint layer bonded; S4 test the test sample by using the X-ray fluorescence spectrometer to obtain the element composition of the dried paint.

[0006] The thickness of the paint layer is 1-5 mm.

[0007] The epoxy resin comprises one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin and alicyclic epoxy resin, and the curing agent comprises one or more of amine type curing agent, acid anhydride type curing agent and phenolic curing agent.

[0008] The mass ratio of the epoxy resin to the paint is 100:20-100:100.

[0009] The mass ratio of the epoxy resin to the curing agent is 100:10-100:100.

[0010] The diameter of the mold is 30-35 mm, and the height is 10-50 mm.

[0011] The curing temperature is 25-200 DEG C, and the curing time is 2-24 h.

[0012] When the X-ray fluorescence spectrometer is used for testing, the paint is faced to the X-ray generator.

[0013] The element composition of the dried paint is calculated to obtain the element composition of the to-be-tested paint, and the calculation method is that the element composition of the dried paint is multiplied by the mass of the dried paint and then divided by the mass of the to-be-tested paint.

[0014] The beneficial effects of the present application are as follows: The present application can obtain the test sample with the epoxy resin and the paint bonded by once injecting a sufficient amount of paint into the mold and then fixing the paint with the resin after drying, and the sample is once formed, the structure is stable, and the method has the advantages of convenient sample preparation, rapid and accurate detection, etc. The method can obtain the composition of various heavy metal elements and other harmful elements in the paint sample at one time, which is helpful for quickly screening out green and environmentally-friendly paint and has good application value. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The preparation flowchart of the present application is shown in the figure; Figure 2 The physical sample of the prepared test sample is shown in the figure. DETAILED DESCRIPTION

[0016] This invention addresses the shortcomings of existing paint elemental measurement techniques by providing a method for measuring the elemental composition of paint using X-ray fluorescence spectroscopy. This method is simple to operate, provides stable and reliable measurement results, and can simultaneously determine the content of multiple elements in paint. The following specific embodiments further illustrate how to prepare test samples and obtain the elemental composition of paint using X-ray fluorescence.

[0017] In the examples, the bisphenol A type epoxy resin and amine curing agent were purchased from Nanchang Chenfang Adhesive Products Co., Ltd.

[0018] Example 1 like Figure 1 As shown, a method for determining the elemental composition of paint using X-ray fluorescence technology includes the following steps: S1 Take a cylindrical mold that is open at the top and sealed at the bottom. The diameter and height of the mold are 30 mm and 15 mm, respectively. S2 Add 2 g of the paint to be tested into the mold and dry it in an oven at 50℃ for 24 h to form a paint layer at the bottom of the mold. Record the weight change of the paint before and after drying. S3. Mix bisphenol A type epoxy resin and amine curing agent at a weight ratio of 1:1. Take 5 g of the mixed resin and add it to the mold so that the epoxy resin completely covers the dried paint surface to be tested. S4 should be left to stand at room temperature for 24 hours to allow the epoxy resin to fully cure. S5 Remove the mold to prepare a test sample for X-ray fluorescence testing, in which the epoxy resin layer and paint layer are bonded together. S6 The prepared test sample is subjected to elemental analysis using a Bruker S8 Tiger X-ray fluorescence spectrometer with a sample cell window of 28 mm. The paint is placed facing the X-ray generator to determine the elemental composition (mass percentage) of the dried paint.

[0019] The paint to be tested is green, red, or white. A sample of the test specimen prepared with green paint is shown in the image below. Figure 2 As shown.

[0020] The results obtained from the three types of dried paint are shown in Table 1.

[0021] Finally, by multiplying the measured mass percentage of elements in the dried paint by the mass of the dried paint and dividing by the mass of the liquid paint, the mass percentage of each element in the liquid paint can be obtained, as shown in Table 2.

[0022] Table 1. Mass percentage of elements in different colored dried paints as determined by X-ray fluorescence. Table 2 Mass percent of elements in different color liquid paints tested by X-ray fluorescence

Claims

1. A method for determining the elemental composition of paint using X-ray fluorescence technique, characterized in that: Includes the following steps: S1 The paint to be tested is added to a cylindrical mold and dried to form a paint layer at the bottom of the mold; the thickness of the paint layer is ≥1mm; S2 Mix epoxy resin and curing agent evenly, add to mold and cover with paint layer to cure epoxy resin and firmly bond it to the bottom paint layer; S3 Remove the mold to prepare a test sample of the bonding between the epoxy resin layer and the paint layer; S4 The elemental composition of the dried paint was determined by X-ray fluorescence spectroscopy.

2. The method for determining the elemental composition of paint using X-ray fluorescence technology as described in claim 1, characterized in that: The thickness of the paint layer is 1-5 mm.

3. The method for determining the elemental composition of paint using X-ray fluorescence technology as described in claim 1, characterized in that: The epoxy resin includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin and alicyclic epoxy resin, and the curing agent includes one or more of amine curing agents, acid anhydride curing agents and phenolic curing agents.

4. The method for determining the elemental composition of paint using X-ray fluorescence technology as described in claim 1, characterized in that: The mass ratio of epoxy resin to paint is 100:20-100:

100.

5. The method for determining the elemental composition of paint using X-ray fluorescence technology as described in claim 1, characterized in that: The mass ratio of epoxy resin to curing agent is 100:10-100:

100.

6. The method for determining the elemental composition of paint using X-ray fluorescence technology as described in claim 1, characterized in that: The mold has a diameter of 30-35 mm and a height of 10-50 mm.

7. The method for determining the elemental composition of paint using X-ray fluorescence technology as described in claim 1, characterized in that: The curing temperature is 25-200 ℃, and the curing time is 2-24 h.

8. The method for determining the elemental composition of paint using X-ray fluorescence technology as described in claim 1, characterized in that: When performing tests with an X-ray fluorescence spectrometer, the paint should be facing the X-ray generator.

9. The method for determining the elemental composition of paint using X-ray fluorescence technology as described in claim 1, characterized in that: It also includes calculating the elemental composition of the paint to be tested from the elemental composition of the dried paint.

Images