CN105092622A - Method for testing relation between pore structure of cigarette paper and release amount of CO in main stream smoke in cigarette burning process - Google Patents

Abstract

The invention discloses a method for testing the relationship between the pore structure of cigarette paper and the amount of CO released in mainstream smoke during the burning process of cigarettes. Characterize, and then use digital image processing technology to extract and analyze the micropore information of cigarette paper, so as to obtain the pore structure parameters such as the number of micropores, the area of micropores, the ratio of micropore area, and the equivalent pore diameter. CO release data can accurately obtain the relationship between cigarette paper pore structure parameters and CO release in mainstream smoke during cigarette burning. This method has the characteristics of strong operability and reliable results. Provide theoretical guidance with production.

Description

A method for testing the relationship between cigarette paper pore structure and CO release in mainstream smoke during cigarette burning

technical field

The invention relates to a cigarette paper pore structure characterization technology, in particular to a scanning electron microscope characterization method for the pore structure of the incompletely cracked area and the completely cracked area of the cigarette paper during the burning process of the cigarette, belonging to the field of cigarettes.

Background technique

How to reduce the harm of smoking to human health is an important research topic in the cigarette industry. With the continuous improvement of people's living standards, consumers are becoming more and more aware of the safety of smoking. Therefore, the development of low-harm cigarettes is not only an inevitable trend in the development of the tobacco industry, but also the State Tobacco Monopoly Administration's policy on reducing the tar and harm of cigarettes in the industry. One of the development strategies.

The pore structure parameters of cigarette paper (micropore number, pore area, pore area ratio, and equivalent pore diameter), especially the pore structure parameters of cigarette paper near the carbonization line 2-4mm, can significantly affect the volatile harmful component CO in mainstream smoke. The diffusion of oxygen and the amount of oxygen entering the combustion cone will affect the release of harmful substances such as CO and tar in the mainstream smoke. It is of great significance to study the characterization method of cigarette paper pore structure near the carbonization line to guide the design and production of low-tar and low-hazard cigarettes. So far, in the field of cigarette paper at home and abroad, only the physical parameter of air permeability is roughly used to characterize the air permeability of cigarette paper, and a set of detailed characterization methods for the pore structure parameters of cigarette paper have not been established; there is no pore structure parameter of cigarette paper A detailed report on the effects on CO emissions in mainstream smoke. Therefore, finding a simple and effective method that can accurately characterize the structural parameters of cigarette paper has important guiding significance for cigarette design and research on harm reduction and tar reduction in the tobacco industry.

Contents of the invention

In view of the fact that the existing technology cannot accurately characterize the influence of pore structure parameters such as the number of micropores, micropore area, micropore area ratio, and equivalent pore diameter of cigarette paper on the CO release in mainstream smoke during the cigarette burning process, it cannot meet the needs of industry development. The purpose of the present invention is to provide a method that is simple to operate and can accurately characterize the relationship between pore structure parameters such as the number of micropores and equivalent pore diameter of cigarette paper during the combustion process of cigarettes, and the CO release in mainstream smoke. Research and production provide theoretical guidance.

In order to achieve the technical purpose of the present invention, the present invention provides a method for testing the relationship between the cigarette paper pore structure and the amount of CO released in mainstream smoke during cigarette burning, the method comprising the following steps:

(1) Collect the cigarette paper in the 2-4 mm area near the carbonization line during the cigarette burning process in situ, fix the cigarette paper on the sample platform, and spray gold to obtain the sample to be tested;

(2) Obtain the micropore image of the cigarette paper by the scanning electron microscope of the obtained sample to be tested, then randomly select the micropore image of a certain local area of the cigarette paper for binarization, and perform edge processing on the micropore image of the local area of the cigarette paper Finally, calculate the aperture and area of each micropore; count the number of micropores, and carry out distribution statistics on the distribution of micropores;

(3) Calculate micropore area A and micropore average area by ImageJ software Micropore area ratio ρ _i and equivalent pore diameter D;

(4) Combining the data of CO release in mainstream smoke during cigarette burning and the micropore parameters of cigarette paper obtained in (3), it is concluded that CO release in mainstream smoke is related to the number of micropores and equivalent pore diameter in cigarette paper near the carbonization line , and the more the number of micropores and the smaller the equivalent pore size, the lower the CO emission in mainstream smoke.

The technical solution of the present invention combines in-situ sampling and scanning electron microscopy techniques with statistical methods to obtain the micropore area A and the average micropore area of cigarette paper during the burning process of cigarettes more intuitively and accurately. Data such as micropore area ratio ρ _i and equivalent pore diameter D, and then correlated with the CO release in mainstream smoke in cigarettes, can quickly, intuitively and accurately determine the relationship between the cigarette paper pore structure and CO release in mainstream smoke during cigarette burning. quantitative relationship.

In a preferred solution, the 2-4mm area near the carbonization line of the cigarette paper includes a part of the cigarette paper not completely cracked and a part of the cigarette paper where the combustion cone end is completely cracked. During the burning process of cigarettes, the cigarette paper near the charring line is generally divided into three different areas according to the burning state (see Figure 1). The unburned area outside the range of 2-4 mm from the charring line is the preheating area; the area within 2-4 mm near the charring line includes the incomplete cracking area of the cigarette paper and the complete cracking area of the cigarette paper at the burning cone end. The 2-4 mm area near the carbonization line of cigarette paper can most accurately characterize the relationship between the pore structure of cigarette paper and the amount of CO released in mainstream smoke during cigarette combustion.

In a preferred method, the cigarette paper is fixed on the sample stage by conductive double-sided adhesive tape.

In the preferred method,

Micropore area A=SUM(A _i ,i=1,2,...,n), A _i is the area of the i-th micropore;

average micropore area $\stackrel{\‾}{A}=(1/\mathrm{no})\×Sum(A_i,i=1,2,...,\mathrm{no}),$ A _i is the area of the ith micropore;

Micropore area ratio ρ _i =A/A _measure , where A _measure. is the local area of the cigarette paper;

Equivalent pore size $\mathrm{D.}=\sqrt{4\×\stackrel{\‾}{\frac{A}{\mathrm{\π}}}}.$

In a more preferred method, during the calculation of the micropore area, any connected area among all the micropores of the cigarette paper is treated as a micropore and included in the micropore area.

In a preferred solution, the working voltage of the scanning electron microscope is 10.00kV, the overall micropore image of the cigarette paper is measured at a resolution of 100 μm, and then the local micropore image of the cigarette paper is measured and selected at a resolution of 20 μm.

The scanning electron microscope adopted in the method of the present invention can be a conventional scanning electron microscope, such as a ZESSEVO18 scanning electron microscope (Germany ZEISS company).

In a preferred solution, edge processing is performed on the image, also called edge detection, for the purpose of marking points with obvious brightness changes in the digital image, which is a process of identifying holes caused by cracking of cigarette paper. The edge processing method is to detect the boundary by finding the maximum and minimum values in the first derivative of the image, usually locating the boundary in the direction of the largest gradient.

In the present invention, the CO emission data of the mainstream smoke during the combustion process of the test cigarettes is obtained by testing with conventional methods, such as testing with a rotary smoking machine.

Compared with the prior art, the beneficial effect brought by the technical solution of the present invention: the present invention adopts the in-situ sampling method combined with the SEM characterization means for the first time, and establishes the cigarette paper holes in the incomplete cracking area and the complete cracking area near the charring line in the cigarette burning process. The structural characterization method can more accurately characterize the change of cigarette paper pore structure during cigarette burning, and further combine the data of CO release in mainstream smoke during cigarette burning, and can accurately obtain the number of micropores and equivalent pore diameter of cigarette paper pores. Relationship between structural parameters and CO release in mainstream smoke. The results of a large number of experimental verifications show that the amount of CO released from mainstream smoke is closely related to the number of micropores and the equivalent pore diameter of cigarette paper in the incompletely cracked area and the completely cracked area, that is, the more the number of micropores and the smaller the equivalent pore size, the greater the CO release rate in mainstream smoke. The test method is simple and effective, and can provide theoretical guidance for the research and production of cigarette paper with low CO emission.

Description of drawings

[Figure 1] Different combustion state areas of cigarette paper near the carbonization line; 1 is the cigarette paper in the completely cracked area, 2 is the cigarette paper in the incompletely cracked area, and 3 is the preheating area of the unburned cigarette paper.

[Figure 2] is the SEM image of the cigarette paper in the incompletely cracked area in Example 1, Example 2 and Example 3: Figure 2(a) is Example 1, Figure 2(b) is Example 2, and Figure 2( c) is embodiment 3.

[Figure 3] is the SEM image of cigarette paper in the completely cracked area in Example 1, Example 2 and Example 3: Figure 3(a) is Example 1, Figure 3(b) is Example 2, Figure 3(c ) is embodiment 3.

Detailed ways

The following examples are intended to illustrate the present invention, rather than to further limit the protection scope of the present invention.

Example 1

The cigarette paper in the completely decomposed area and the cigarette paper in the incompletely decomposed area were gently picked up with tweezers and fixed on the sample stage with conductive double-sided adhesive for gold spraying treatment. The prepared sample was placed in the ZESSEVO18 scanning electron microscope sample chamber and vacuumized. The morphology of the cigarette paper was observed under the working voltage of 10.00kV, and the magnification of the SEM was adjusted to obtain the overall and local micropore images. Binarize the image, then process the edge of the image, further calculate the aperture and area of each micropore, and count the number of micropores. Finally, the distribution statistics of the micropore distribution are carried out. Calculation of micropore area (A) and micropore average area by optimized and improved software Micropore area ratio (ρ _i ) and equivalent pore diameter (D). The pore structure parameters of the cigarette paper in the incompletely cracked area and the completely cracked area are shown in Table 1 and Table 2. The results in Table 1 and Table 2 show that the number of micropores in the cigarette paper in the incompletely cracked area and the completely cracked area in Example 1 were respectively There are 6730 and 10555 pieces; the equivalent pore diameters are 1.09 and 1.38 μm.

After the cigarette paper is made into cigarettes, a rotary smoking machine is used to test the CO release in the mainstream smoke during the cigarette combustion process (see the data in Table 3); combined with the SEM characterization results of the cigarette paper pore structure, the CO release in the mainstream smoke during the cigarette burning process can be obtained The relationship between the number of pores in cigarette paper and the equivalent pore size. The results show that the CO release in mainstream smoke is related to the number of micropores in the incompletely cracked area and the completely cracked area of cigarette paper and the equivalent pore size, and the more the number of micropores and the smaller the equivalent pore size, the lower the CO release in mainstream smoke .

Example 2

The cigarette paper in the completely decomposed area and the cigarette paper in the incompletely decomposed area were gently picked up with tweezers and fixed on the sample stage with conductive double-sided adhesive for gold spraying treatment. The prepared sample was placed in the ZESSEVO18 scanning electron microscope sample chamber and vacuumized. The morphology of the cigarette paper was observed under the working voltage of 10.00kV, and the magnification of the SEM was adjusted to obtain the overall and local micropore images. Binarize the image, then process the edge of the image, further calculate the aperture and area of each micropore, and count the number of micropores. Finally, the distribution statistics of the distribution of micropores are carried out. Calculation of micropore area (A) and micropore average area by optimized and improved software Micropore area ratio (ρ _i ) and equivalent pore diameter (D). The pore structure parameters of the cigarette paper in the incompletely cracked area and the completely cracked area are shown in Table 1 and Table 2. The results in Table 1 and Table 2 show that the number of micropores in the cigarette paper in the incompletely cracked area and the completely cracked area in Example 2 were respectively There are 8457 and 12570 pieces; the equivalent pore diameters are 0.96 and 1.21 μm.

After the cigarette paper is made into cigarettes, a rotary smoking machine is used to test the CO release in the mainstream smoke during the cigarette combustion process (see the data in Table 3); combined with the SEM characterization results of the cigarette paper pore structure, the CO release in the mainstream smoke during the cigarette burning process can be obtained The relationship between the number of pores in cigarette paper and the equivalent pore size. The results show that the CO release in mainstream smoke is related to the number of micropores in the incompletely cracked area and the completely cracked area of cigarette paper and the equivalent pore size, and the more the number of micropores and the smaller the equivalent pore size, the lower the CO release in mainstream smoke .

Example 3

The cigarette paper in the completely decomposed area and the cigarette paper in the incompletely decomposed area were gently picked up with tweezers and fixed on the sample stage with conductive double-sided adhesive for gold spraying treatment. The prepared sample was placed in the ZESSEVO18 scanning electron microscope sample chamber and vacuumized. The morphology of the cigarette paper was observed under the working voltage of 10.00kV, and the magnification of the SEM was adjusted to obtain the overall and local micropore images. Binarize the image, then process the edge of the image, further calculate the aperture and area of each micropore, and count the number of micropores. Finally, the distribution statistics of the micropore distribution are carried out. Calculation of micropore area (A) and micropore average area by optimized and improved software Micropore area ratio (ρ _i ) and equivalent pore diameter (D). The pore structure parameters of the cigarette paper in the incompletely cracked area and the completely cracked area are shown in Table 1 and Table 2. The results in Table 1 and Table 2 show that the number of micropores in the cigarette paper in the incompletely cracked area and the completely cracked area in Example 3 were respectively There are 9936 and 15815 pieces; the equivalent pore diameters are 0.84 and 1.05 μm.

After the cigarette paper is made into cigarettes, a rotary smoking machine is used to test the CO release in the mainstream smoke during the cigarette combustion process (see the data in Table 3); combined with the SEM characterization results of the cigarette paper pore structure, the CO release in the mainstream smoke during the cigarette burning process can be obtained The relationship between the number of pores in cigarette paper and the equivalent pore size. The results show that the CO release in mainstream smoke is related to the number of micropores in the incompletely cracked area and the completely cracked area of cigarette paper and the equivalent pore size, and the more the number of micropores and the smaller the equivalent pore size, the lower the CO release in mainstream smoke .

Table 1 Micropore structure parameters in the incompletely cracked area of cigarette paper

Table 2 Micropore structure parameters in the completely cracked area of cigarette paper

Table 3 Cigarette mainstream smoke conventional smoke release

Claims (6)

1. A method for testing the relationship between the cigarette paper hole structure and the amount of CO release in the mainstream smoke during the burning process of a cigarette, characterized in that it comprises the following steps: (1) Collect the cigarette paper in the 2-4 mm area near the carbonization line during the cigarette burning process in situ, fix the cigarette paper on the sample platform, and spray gold to obtain the sample to be tested; (2) Obtain the micropore image of the cigarette paper by the scanning electron microscope of the obtained sample to be tested, then randomly select the micropore image of a certain local area of the cigarette paper for binarization, and perform edge processing on the micropore image of the local area of the cigarette paper Finally, calculate the aperture and area of each micropore; count the number of micropores, and carry out distribution statistics on the distribution of micropores; (3) Calculate micropore area A and micropore average area by ImageJ software Micropore area ratio ρ _i and equivalent pore diameter D; (4) Combining the data of CO release in mainstream smoke during cigarette burning and the micropore parameters of cigarette paper obtained in (3), it is concluded that CO release in mainstream smoke is related to the number of micropores and equivalent pore diameter in cigarette paper near the carbonization line , and the more the number of micropores and the smaller the equivalent pore size, the lower the CO emission in mainstream smoke. 2. The method for testing the relationship between the pore structure of the cigarette paper and the amount of CO released in the mainstream smoke during the combustion process of the cigarette according to claim 1, characterized in that the 2-4mm area near the carbonization line of the cigarette paper includes a part of the cigarette paper that is not completely cracked area and a portion of the burning cone of the cigarette paper completely cracks the area. 3. The method for testing the relationship between cigarette paper pore structure and CO release in mainstream smoke during cigarette burning according to claim 1, characterized in that the cigarette paper is fixed on the sample stage by conductive double-sided adhesive. 4. the method for the relationship between the cigarette paper pore structure and the amount of CO released in the mainstream smoke in the test cigarette burning process according to claim 1, characterized in that, Micropore area A=SUM(A _i ,i=1,2,...,n), A _i is the area of the i-th micropore; average micropore area A _i is the area of the ith micropore; Micropore area ratio ρ _i =A/A _measure , where A _measure. is the local area of the cigarette paper; Equivalent pore size $\mathrm{D.}=\sqrt{4\×\stackrel{\‾}{\frac{A}{\mathrm{\π}}}}.$ 5. the method for the relationship between the cigarette paper pore structure and the amount of CO released in the mainstream smoke in the test cigarette burning process according to claim 4, it is characterized in that, in the calculation process of the micropore area, all the micropores of the cigarette paper are arbitrarily A connected area is treated as a micropore and counted into the micropore area. 6. The method for testing the relationship between the pore structure of cigarette paper and the amount of CO released in mainstream smoke during the burning process of cigarettes according to claim 1, characterized in that, the operating voltage of the scanning electron microscope is 10.00kV, and the magnification is 500 Measure the overall micropore image of cigarette paper under the condition of magnification of 2000 times, and then measure and select the local micropore image of cigarette paper under the condition of magnification of 2000 times.