Coated paper and detection method and detection device for coating weight of coating of coated paper

Abstract

The invention provides coated paper and a detection method and a detection device for the coating weight of a coating of the coated paper. The detection method comprises the following steps: acquiring a section electronic scanning graph and an element distribution graph of the paper; superposing the element distribution diagram and the electronic scanning diagram to obtain an element superposition diagram; and counting the number of pixel points in the area occupied by the elements, and calculating to obtain the coating weight of each coating. According to the method for detecting the coating weight of the coating of the coated paper provided by the embodiment of the invention, the areas contained in the prime coat and the top coat are distinguished by obtaining the section electronic scanning graph and the element distribution graph of the paper and through the difference of the composition of the pigments in the coatings of different layers; and image analysis software is utilized to calculate the pixel area of each coating so as to obtain the coating weight of each coating, and the method has the characteristics of convenience in operation and accuracy in detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paper detection, in particular to a coated paper and a detection method and device for the coating amount of the coating layer of the coated paper. BACKGROUND

[0002] The core feature of multi-layer coating of paper is to achieve comprehensive performance that a single coating layer cannot achieve by coating different functional coatings multiple times. It has the following advantages:

[0003] 1. Functional diversification: Different coatings can assume different functions, such as enhancing paper strength with the bottom layer, improving smoothness with the middle layer, and achieving waterproofness or print adaptability with the surface layer, which can meet multiple use requirements at the same time.

[0004] 2. Better performance: Multi-layer coating can precisely control the thickness and composition of each layer, reduce coating defects (such as bubbles and pinholes), and improve the surface uniformity, gloss, and printing effect (such as color reproduction and ink adhesion) of the paper.

[0005] 3. High material utilization rate: Select cost-effective materials according to the needs of each layer, such as low-cost fillers for the bottom layer and high-performance resins for the surface layer, which can reduce costs while ensuring performance.

[0006] 4. Strong adaptability: It can customize coating combinations for different application scenarios (such as packaging paper, copper plate paper, and special paper) to meet the special requirements (such as folding resistance and corrosion resistance) of specific industries.

[0007] Currently, there is no method to measure the coating amount of each coating layer when multi-layer coating is used in paper analysis, which causes difficulties in evaluating experimental results, reducing costs, and analyzing the physicochemical properties of the coating layer. SUMMARY

[0008] The first aspect of the embodiment of the present application provides a detection method for the coating amount of the coating layer of a coated paper, which comprises:

[0009] Obtaining a cross-sectional electron scanning image and an element distribution image of the paper;

[0010] Superimposing the element distribution image and the electron scanning image to obtain an element superimposed image;

[0011] Counting the number of pixel points in the area occupied by the element and calculating the coating amount of each coating layer.

[0012] In some optional embodiments, the step of obtaining the cross-sectional electron scanning image of the paper comprises embedding and solidifying the paper to be detected, cutting out the sample cross-section to be photographed, and using an electron microscope to scan and photograph the sample cross-section to obtain the cross-sectional electron scanning image.

[0013] In some optional embodiments, the step of embedding and curing the paper to be detected uses transparent resin to embed and cure the paper.

[0014] In some optional embodiments, the step of obtaining the cross-section element distribution map uses an x-ray spectrometer to scan different elements of different coatings and obtain a distribution map of different elements of different coatings.

[0015] In some optional embodiments, the step of using an x-ray spectrometer to scan different elements of different coatings uses different elements of adjacent coatings as target elements to be scanned.

[0016] In some optional embodiments, the target elements to be scanned include any one of Si, Al, Mg, Ca, and Ti.

[0017] In some optional embodiments, the step of superimposing the element distribution map and the electron scanning map to obtain an element superimposed map includes superimposing the distribution map of target elements of different layers and the electron scanning map of the corresponding coating to obtain an element superimposed map.

[0018] In some optional embodiments, the step of counting the number of pixel points of the area occupied by the elements and calculating the coating amount of each coating includes using image processing software to count the number of pixel points of the area occupied by the target elements and the total number of pixel points of all coatings, and calculating the coating amount ratio according to the pixel point ratio of the target elements.

[0019] In a second aspect, the embodiments of the present application provide a paper coating coating amount detection device, the detection device comprising:

[0020] An acquisition module is configured to acquire a cross-section electron scanning map and an element distribution map of the paper.

[0021] A superimposition module is configured to superimpose the element distribution map and the electron scanning map to obtain an element superimposed map.

[0022] A calculation module is configured to count the number of pixel points of the area occupied by the elements and calculate the coating amount of each coating.

[0023] In a third aspect, the embodiments of the present application provide a coated paper, which is coated by using the detection method described in the above embodiments.

[0024] The coating amount detection method of the coating layer of the coated paper provided by the embodiment of the application has the characteristics of convenient operation and accurate detection. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and all other drawings obtained by those skilled in the art without any creative effort are within the protection scope of the application.

[0026] Figure 1 is a flowchart of the coating amount detection method of the coating layer of the coated paper according to an embodiment of the application;

[0027] Figure 2 is the cross-section electron scanning of the coated paper according to an embodiment of the application; Figure 1 is a flowchart of the coating amount detection method of the coating layer of the coated paper according to an embodiment of the application;

[0028] Figure 3 is the cross-section electron scanning of the coating layer of the coated paper;

[0029] Figure 4 is the Si and Ca element distribution diagram of the coating layer of the coated paper and Figure 3 is the element superimposed diagram obtained by superimposing the Si and Ca element distribution diagram of the coating layer of the coated paper;

[0030] Figure 5 is a schematic diagram of the image processing process using the lasso tool in the PC;

[0031] Figure 6 is a structure composition block diagram of the coating amount detection device of the coating layer of the coated paper according to an embodiment of the application. DETAILED DESCRIPTION

[0032] The application will be described in further detail below in combination with the drawings and embodiments. It is particularly pointed out that the following embodiments are only used to illustrate the application, but do not limit the scope of the application. Similarly, the following embodiments are only some embodiments of the application, but not all embodiments of the application, and all other embodiments obtained by those skilled in the art without any creative effort are within the protection scope of the application.

[0033] The terms "first", "second", "third" in the embodiments of the present application are only used for descriptive purpose and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second", "third" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise explicitly and specifically limited. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly. The terms "include" and "have" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or components inherent to the process, method, product or device.

[0034] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase that the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described herein can be combined with other embodiments.

[0035] The coating amount of coated paper is usually 5-50g, and the coating amount of some high weight paper can be more than 50g. The most common coating is 2 or 3 layers. Since the layers are tightly combined, there is no test method for the coating amount of each layer of the composite coating.

[0036] The present application obtains the cross-sectional picture of the surface coating of the paper and tests the element composition by electron microscope and EDS spectrometer, and distinguishes the areas contained by the base coating and the top coating through the difference in the pigment composition of the different layers. Then the coating amount of each layer is obtained by calculating the pixel area of each layer by image analysis software.

[0037] The embodiments of the present application first provide a detection method for the coating amount of the coating of coated paper, please refer to Figure 1 , Figure 1 is a flowchart of the detection method for the coating amount of the coating of coated paper, which includes but is not limited to the following steps.

[0038] In step S100, the cross-sectional electron scanning picture and the element distribution picture of the paper are obtained.

[0039] This step first describes the method for obtaining a cross-sectional electronic scan of the paper. Please refer to [link / reference]. Figure 2 , Figure 2 This application obtains a cross-sectional electronic scan of the paper. Figure 1 The flowchart of the embodiment shows that the method includes the following steps.

[0040] Step S110: Embed and solidify the paper to be tested.

[0041] In this step, the copper plate sample (coated paper) to be tested can be cut into a paper sample of a suitable size for the resin embedding plate (in this embodiment, it can be 1cm*2cm), and the sample can be cured using a suitable transparent resin embedding solution (in this embodiment, the 812 resin kit is used).

[0042] Step S120: Cut out the cross-section of the sample to be photographed.

[0043] In step S120, the cured sample is prepared by using a suitable microtome (in this case, a Leica RM2165 with a diamond blade) to create a smooth observation surface. Preparation requirements: smooth surface, no missing coating.

[0044] Step S130: Scan the sample cross-section using an electron microscope and obtain a cross-sectional electron scan image.

[0045] In this step, a scanning electron microscope (SEM) can be used (in this case, a JSE6360 from NEC) to take SEM images of the sample end face. The magnification of the end face images is typically chosen between 500-1000x, depending on the specific paper weight and coating thickness. Generally, 1000x is used for low weights (128g and below), while 500-1000x is used for weights above 128g.

[0046] Step S100 also includes obtaining an elemental distribution map of the paper. Specifically, this step may involve using an X-ray spectrometer to scan different elements in different coatings and obtain a distribution map of the different elements in the coatings. Adjacent coatings are selected with different elements as the target elements to be scanned, and the target elements include any one of Si, Al, Mg, Ca, and Ti.

[0047] The copper plate paper using porcelain clay as pigment in surface coating paint is taken as an example to test the coating amount of the base coating and the surface coating. The element distribution maps of the different elements of the base coating and the surface coating are superimposed to form the boundary line between the different coatings. For example, calcium carbonate is often used as pigment in the base coating. The surface coating needs to provide different gloss and printing suitability, and the common elements are Si, Al, Mg and the like. The Ca and Si elements are selected as the target elements. The Si element is selected as the characteristic element of the surface coating, and the Si element distribution map is derived. The Ca element is selected as the characteristic element of the base coating, and the Ca element distribution map is derived.

[0048] Please continue to refer to Figure 1 The detection method in the embodiment further includes the step S200 of superimposing the element distribution map and the electron scanning map to obtain an element superimposed map.

[0049] In this step, the distribution map of the target element of different layers can be superimposed with the electron scanning map of the corresponding coating layer to obtain an element superimposed map.

[0050] In the embodiment, the Si and Ca element distribution maps derived above can be superimposed with the corresponding SEM map, and a picture is generated. Please refer to Figure 3 and Figure 4 , Figure 3 is a cross-sectional electron scanning map of the coating layer of the coated paper, Figure 4 is the element superimposed map obtained by superimposing the Si and Ca element distribution maps of Figure 3 .

[0051] Please continue to refer to Figure 1 The detection method in the embodiment further includes the step S300 of counting the number of pixel points of the area occupied by the element and calculating the coating amount of each coating layer.

[0052] In this step, the number of pixel points of the area occupied by the target element and the total number of pixel points of all coating layers can be counted by using image processing software, and the coating amount ratio can be calculated according to the pixel point number ratio of the target element.

[0053] The image tool software such as PS can be used to process the picture. Please refer to Figure 5 , Figure 5 is a picture processing process diagram using the lasso tool in the PC, in which the lasso tool in the PS is used to select the Si element distribution area (red part) in the picture and the area (yellow area) in the coating layer not containing the Si element. The record measurement under the analysis menu is used to automatically calculate the pixel points in the picture. The pixel point number statistics can be used to calculate the ratio of the Si element distribution area in the total coating layer.

[0054] Si element area pixel points 182648 Si element-free area pixel points 182850 total coating pixel points 365498

[0055] In the formula, the pixel points of the Si element region are the face coating region. The pixel points of the region without Si element (or the region with Ca element) are the base coating region.

[0056] The calculation method of the coating amount of each layer is as follows.

[0057] A. Calculation of the coating amount of each pixel point

[0058] The copper plate paper with known coating amount is made in the laboratory, and the total pixel points of the total coating layer are obtained according to the above steps.

[0059] Coating amount / pixel points in the coating layer = total coating amount / total pixel points in the coating layer

[0060] Coating amount = known coating amount made in the laboratory (g / m 2 )

[0061] Pixel points in the coating layer = the number of pixel points counted by the PS tool in the cross-sectional picture

[0062] B. Calculation of the coating amount of the base coating and the face coating

[0063] Coating amount of the base coating = coating amount / each pixel point * the number of pixel points of the base coating counted by the PS tool in the cross-sectional picture

[0064] Coating amount of the face coating = coating amount / each pixel point * the number of pixel points of the face coating counted by the PS tool in the cross-sectional picture

[0065] The detection method of the coating amount of the coating layer of the coated paper provided in the embodiments of the present application obtains the cross-sectional electron scanning picture and the element distribution picture of the paper, and distinguishes the regions contained in the base coating and the face coating according to the difference in the pigment composition in different layers of the coating layer, and then calculates the pixel area of each coating layer by using the image analysis software to obtain the coating amount of each coating layer, so that the method has the characteristics of convenient operation and accurate detection.

[0066] In addition, the embodiments of the present application also provide a detection device for the coating amount of the coating layer of paper. Please refer to Figure 6 , Figure 6 is a structure composition block diagram of an embodiment of the detection device for the coating amount of the coating layer of paper, and the detection device 600 includes but is not limited to the following modules: an acquisition module 610, a superposition module 620 and a calculation module 630. The acquisition module 610 is used to acquire the cross-sectional electron scanning picture and the element distribution picture of the paper; the superposition module 620 is used to superimpose the element distribution picture and the electron scanning picture to obtain an element superposition picture; and the calculation module 630 is used to count the number of pixel points of the region occupied by the element and calculate the coating amount of each coating layer. The specific execution method of each module can be referred to the related description of the foregoing embodiments, which will not be described here again.

[0067] The coating amount detection device of the coated paper in the embodiment has the characteristics of convenient operation and accurate detection by obtaining the cross-section electron scanning image and the element distribution image of the paper, distinguishing the areas contained by the base coat and the top coat through the difference of the pigment composition in different layers of the coating, and calculating the pixel area of each coating layer by using the image analysis software to obtain the coating amount of each coating layer.

[0068] The above only describes some embodiments of the application, and does not limit the protection scope of the application, and any equivalent device or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the application.

Claims

1. A method of detecting a coating amount of a coating layer of a coated paper, characterized by, The detection method comprises: obtaining a cross-section electron scanning image and an element distribution image of the paper; superimposing the element distribution image and the electron scanning image to obtain an element superimposed image; counting the number of pixel points of the area occupied by the element and calculating the coating amount of each coating layer.

2. The detection method according to claim 1, characterized in that, The step of obtaining the cross-section electron scanning image of the paper comprises: embedding and curing the paper to be detected; cutting out a sample cross-section to be photographed; scanning and photographing the sample cross-section by using an electron microscope to obtain the cross-section electron scanning image.

3. The detection method according to claim 2, characterized in that, In the step of embedding and curing the paper to be detected, the paper is embedded and cured by using transparent resin.

4. The method of claim 1, wherein, The step of obtaining the cross-section element distribution image of the paper comprises: scanning different elements of different coating layers by using an x-ray spectrometer, and obtaining a distribution image of different elements of different coating layers.

5. The detection method according to claim 4, characterized in that, In the step of scanning different elements of different coating layers by using the x-ray spectrometer, different elements are selected as target elements to be scanned for adjacent coating layers.

6. The detection method according to claim 5, characterized in that, The target elements to be scanned include any one of Si, Al, Mg, Ca and Ti.

7. The detection method according to claim 5, characterized in that, The step of superimposing the element distribution image and the electron scanning image to obtain the element superimposed image comprises: superimposing the distribution image of the target element of different layers and the electron scanning image of the corresponding coating layer to obtain the element superimposed image.

8. The method of claim 1, wherein, The step of counting the number of pixel points of the area occupied by the element and calculating the coating amount of each coating layer comprises: counting the number of pixel points of the area occupied by the target element and the total number of pixel points of all coating layers by using image processing software, and calculating the coating amount ratio according to the pixel point ratio of the target element.

9. A device for detecting the coating amount of paper, characterized in that, The detection device comprises: an acquisition module for obtaining a cross-section electron scanning image and an element distribution image of the paper; a superimposition module for superimposing the element distribution image and the electron scanning image to obtain an element superimposed image; a calculation module for counting the number of pixel points of the area occupied by the element and calculating the coating amount of each coating layer.

10. A coated paper, characterized by The coated paper is subjected to coating layer coating amount detection by using the detection method according to any one of claims 1-8.

Images