A method for infrared testing weather resistance of titanium dioxide

Abstract

The invention discloses a method for infrared testing the weather resistance of titanium dioxide, and belongs to the field of titanium dioxide testing. The invention solves the problems that the titanium dioxide weather resistance testing method in the prior art is time-consuming and there are human errors in the coating process. The invention comprises the following steps: Step 1.1: heat-treating the finished titanium dioxide product to be tested; Step 1.2: mixing the heat-treated titanium dioxide and KBr in a ratio of (1:13.3)-(1:7.5), grinding them, and then pressing them into transparent sheets; Step 2.1: infrared testing the transparent sheets prepared in step 1.2, and recording 3709-4200cm ‑1 Step 2.2: Detection by infrared method, record 3200-3686cm ‑1 Step 2.3: Calculate the proportion of free hydroxyl groups. The present invention characterizes the weather resistance of titanium dioxide by the proportion of free hydroxyl groups, greatly shortens the detection time, improves the detection efficiency, and has higher accuracy, reducing human errors.

Description

Technical Field

[0001] The invention belongs to the field of titanium dioxide testing, and in particular relates to a method for infrared testing the weather resistance of titanium dioxide. Background Art

[0002] Titanium dioxide is an important chemical raw material and an important white pigment. It is non-toxic and environmentally friendly and is widely used in coatings, plastics, papermaking, inks and other industries. In these industries, weather resistance is an indicator that most downstream customers value. Titanium dioxide needs to be coated because of its own catalytic effect. Under the excitation of ultraviolet light, titanium dioxide generates electrons and holes. Holes and hydroxyl groups on the surface of titanium dioxide generate hydroxyl radicals. The generated hydroxyl radicals can easily attack polymer molecules, thereby degrading polymer molecules and affecting weather resistance.

[0003] Common methods for testing the weatherability of titanium dioxide include xenon lamp aging, UV aging, natural outdoor exposure, etc. However, the existing titanium dioxide weatherability testing methods take a long time, generally from a few days to a few months, and some natural exposures even take several years. In addition, the existing titanium dioxide weatherability testing methods have the disadvantage of human error in the coating process.

[0004] In order to overcome the above shortcomings, the present invention provides a rapid and accurate method for testing the weather resistance of titanium dioxide. Summary of the invention

[0005] In view of the problems in the prior art that the weather resistance test method of titanium dioxide takes a long time and there are human errors in the coating process, the present invention provides a method for infrared testing the weather resistance of titanium dioxide, the purpose of which is to quickly and accurately characterize the weather resistance of titanium dioxide, reduce human errors, and increase timeliness.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for infrared testing the weather resistance of titanium dioxide comprises the following steps:

[0008] Step 1: Sample processing;

[0009] Step 1.1: Heat treat the titanium dioxide product to be tested;

[0010] Step 1.2: Mix the heat-treated titanium dioxide and KBr in a ratio of (1:13.3)-(1:7.5), grind, and then press into a transparent sheet;

[0011] Step 2: Sample measurement;

[0012] Step 2.1: Perform infrared detection on the transparent sheet made in step 1.2. After removing the background, measure the sample and then -1Select integration within the wavelength range to obtain the peak area S1;

[0013] Step 2.2: Measure the transparent sheet by infrared method, remove the background, measure the sample, and then -1 Select integration within the wavelength range to obtain the peak area S2;

[0014] There are two kinds of hydroxyl groups with high content on the surface of titanium dioxide. One is at 3709-4200cm -1 The presence of a bound hydroxyl group is at 3200-3686cm -1 The free hydroxyl groups existing under the condition of the titanium dioxide are more easily oxidized into hydroxyl radicals by the holes excited by the titanium dioxide. After adopting the technical solution of the present invention, the weather resistance of the titanium dioxide can be characterized by calculating the proportion of free hydroxyl groups. The larger the proportion of free hydroxyl groups, the worse the weather resistance. The present invention shortens the detection time of the weather resistance detection of titanium dioxide from several days, several months or even several years to about 5 minutes, greatly improving the detection efficiency, and the weather resistance of titanium dioxide can be accurately characterized by the proportion of free hydroxyl groups, reducing human errors.

[0015] Preferably, in step 1.1, the heat treatment temperature is 300-400°C, and the heat treatment time is 30-60 min.

[0016] Preferably, in step 1.2, the mass of titanium dioxide is 15-20 μg, the mass of KBr is 150-200 μg, and the pressure is 10-15 Pa.

[0017] Preferably, in step 1.2, the grinding time of titanium dioxide and KBr is 5-20 min.

[0018] Further preferably, in step 2.1 and step 2.2, Fourier infrared equipment is used for detection.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] The present invention characterizes the weather resistance of titanium dioxide by calculating the proportion of free hydroxyl groups. The larger the proportion of free hydroxyl groups, the worse the weather resistance. The detection time of titanium dioxide weather resistance detection is shortened from several days, several months or even several years to about 5 minutes, which greatly improves the detection efficiency. Moreover, the weather resistance of titanium dioxide can be accurately characterized by the proportion of free hydroxyl groups, which reduces human errors. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Therefore, the following detailed description of the embodiments of the present application is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0022] Example 1

[0023] Step 1: Sample processing

[0024] 1) Heat treat the finished titanium dioxide product to be tested at 300°C.

[0025] 2) Take 15 μg of the treated titanium dioxide and mix it with 150 μg of KBr, grind it for 5 minutes, and make it into a transparent sheet under a pressure of 10 MPa.

[0026] Step 2: Measure the sample

[0027] 1) Use Fourier infrared equipment to detect the transparent sheet by infrared method, and record 3709-4200cm -1 The peak area under S1 = 21900;

[0028] 2) Use Fourier infrared equipment to perform infrared detection on transparent thin films and record 3200-3686cm -1 The peak area under S2 = 18500;

[0029] Weather resistance ΔE is expressed by a ratio calculated using the following formula. The larger the ratio, the worse the weather resistance.

[0030]

[0031] Example 2

[0032] Step 1: Sample processing

[0033] 1) Heat treat the finished titanium dioxide product to be tested at 350°C.

[0034] 2) Take 17 μg of the treated titanium dioxide and mix it with 170 μg of KBr, grind it for 10 minutes, and make it into a transparent sheet at a pressure of 12 MPa.

[0035] Step 2: Measure the sample

[0036] 1) Use Fourier infrared equipment to detect the transparent sheet by infrared method, and record 3709-4200cm -1The peak area under S1 = 20900;

[0037] 2) Use Fourier infrared equipment to perform infrared detection on transparent thin films and record 3200-3686cm -1 The peak area S2 is 17800;

[0038] Weather resistance ΔE is expressed by a ratio calculated using the following formula. The larger the ratio, the worse the weather resistance.

[0039]

[0040] Example 3

[0041] Step 1: Sample processing

[0042] 1) Heat treat the finished titanium dioxide product to be tested at 400°C.

[0043] 2) Take 20 μg of the treated titanium dioxide and mix it with 200 μg of KBr, grind it for 20 minutes, and make it into a transparent sheet at a pressure of 15 MPa.

[0044] Step 2: Measure the sample

[0045] 1) Use Fourier infrared equipment to detect the transparent sheet by infrared method, and record 3709-4200cm -1 The peak area under S1 = 21200;

[0046] 2) Use Fourier infrared equipment to perform infrared detection on transparent thin films and record 3200-3686cm -1 The peak area under S2 = 18900;

[0047] Weather resistance ΔE is expressed by a ratio calculated using the following formula. The larger the ratio, the worse the weather resistance.

[0048]

[0049] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A method for infrared testing of titanium dioxide weather resistance, characterized in that: The following steps are involved: Step 1: Sample processing; Step 1.1: Heat treat the titanium dioxide product to be tested; Step 1.2: Mix the heat-treated titanium dioxide and KBr in a ratio of (1:13.3)-(1:7.5), grind, and then press into a transparent sheet; Step 2: Sample measurement; Step 2.1: Perform infrared detection on the transparent sheet prepared in step 1.

2. After removing the background, measure the sample and then -1 Select integration within the wavelength range of 3709-4200 cm -1 The peak area of ​​the bound hydroxyl group present under the condition is S1; Step 2.2: Measure the transparent sheet by infrared method, remove the background, measure the sample, and then -1 Select integration within the wavelength range of 3200-3686 cm -1 The peak area of ​​free hydroxyl groups present under the condition is S2; Step 2.3: Calculate the free hydroxyl ratio ΔE. Weather resistance is expressed by the ratio calculated using the following formula: ΔE=S2 / (S1+S2) In the formula, ΔE is the proportion of free hydroxyl groups. The larger the ΔE value, the worse the weather resistance.

2. The method for infrared testing weather resistance of titanium dioxide according to claim 1, characterized in that: In step 1.1, the heat treatment temperature is 300-400 °C, and the heat treatment time is 30-60 min.

3. The method for infrared testing weather resistance of titanium dioxide according to claim 1, characterized in that: In step 1.2, the mass of titanium dioxide is 15-20 μg, the mass of KBr is 150-200 μg, and the pressure is 10-15 Pa.

4. The method for infrared testing weather resistance of titanium dioxide according to claim 1, characterized in that: In step 1.2, the grinding time of titanium dioxide and KBr is 5-20 min.

5. The method for infrared testing weather resistance of titanium dioxide according to claim 1, characterized in that: In step 2.1 and step 2.2, Fourier infrared equipment is used for detection.

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