An online film-forming system on the surface of gypsum board

Abstract

The present invention discloses an on-line film-forming system on the surface of a gypsum board, comprising: a coating device and a dryer; the dryer is used for drying the wet gypsum board; the coating device is used for applying an alkaline solution mixed with methylhydrogen siloxane on the front surface of the lower facing paper before the wet gypsum board is dried. It applies an alkaline solution mixed with methylhydrogen siloxane on the front surface of the lower facing paper. There are multiple chemically active Si-H groups in methylhydrogen siloxane. Then the wet gypsum board is dried. During the process of drying the gypsum board under alkaline conditions, the unhydrolyzed Si-H continues to hydrolyze with the water molecules evaporated from the board core to form Si-OH. Part of the Si-OH combines with the facing paper fibers to fix the hydrophobic groups to the front surface of the gypsum board, and the other Si-OH forms a more stable -Si-O- covalent network through self-condensation and covers the front surface of the gypsum board, so that a hydrophobic film is formed on the front surface of the gypsum board.

Description

Technical Field

[0001] The present invention relates to the field of gypsum board production lines, and particularly to an on-line film forming system for the surface of paper-faced gypsum boards. Background Art

[0002] The main components of paper-faced gypsum boards are gypsum, facing paper, and some additives. Both gypsum and facing paper are hygroscopic, and the surface of the facing paper is hydrophilic. In a humid environment, moisture will penetrate through the paper surface into the gypsum core layer.

[0003] To solve this problem, a hydrophobic film can be formed on the front surface of the gypsum board to prevent moisture from penetrating through the paper surface into the gypsum core layer. It is known that the lower facing paper of the gypsum board is the used surface, and one side of the upper facing paper of the gypsum board usually faces the wall or ceiling and is generally not affected by the humid environment. Therefore, it is usually only necessary to form a hydrophobic film on the front surface of the lower facing paper. Summary of the Invention

[0004] The purpose of the present invention is to provide an on-line film forming system for the surface of paper-faced gypsum boards to solve the technical problem of how to form a hydrophobic film on the front surface of the lower facing paper of the gypsum board.

[0005] To solve the above technical problem, the present invention specifically provides the following technical solutions:

[0006] An on-line film forming system for the surface of paper-faced gypsum boards, comprising: a coating device and a dryer; the dryer is used for drying the wet gypsum board; the coating device is used for applying an alkali solution mixed with methylhydrogen siloxane on the front surface of the lower facing paper before the wet gypsum board is dried.

[0007] Further, the coating device is arranged before the lower facing paper scoring machine of the gypsum board production line.

[0008] Further, the coating device is arranged after the lower facing paper deviation rectifier of the gypsum board production line.

[0009] Further, the coating device includes a coating component and a spray gun; both the coating component and the spray gun are arranged on the transmission path of the lower facing paper. The spray gun is connected to an alkali solution source and is used for spraying the alkali solution mixed with methylhydrogen siloxane on the surface of the lower facing paper, and the coating component is used for smoothing the alkali solution on the front surface of the lower facing paper.

[0010] Further, the number of the coating components is at least 2, and the plurality of coating components form a continuous and uninterrupted coating area in the width direction of the lower facing paper, and the position of at least 1 coating component in the width direction of the lower facing paper can be adjusted to change the overall width of the coating area.

[0011] Furthermore, the number of the spray guns is several, and the several spray guns are arranged side by side at equal intervals along the width direction of the lower facing paper, and each spray gun can be independently turned on or off.

[0012] Furthermore, the coating device further includes a support member, and the support member is arranged on the side of the lower facing paper facing away from the coating member. The support member includes a smooth line or surface for supporting the back surface of the lower facing paper to offset the acting force exerted by the coating member on the front surface of the lower facing paper.

[0013] On the other hand, the coating device further includes a belt conveyor, and the belt conveyor is arranged on the side of the lower facing paper facing away from the coating member. The conveying surface of the belt conveyor is attached to the back surface of the lower facing paper. The conveying speed of the belt conveyor is in the same direction and at the same speed as the linear speed of the lower facing paper, and the width of the conveying surface of the belt conveyor is greater than the width of the lower facing paper.

[0014] Furthermore, the coating device further includes a color sensor and a controller. The color sensor is installed between the lower facing paper aligner and the belt conveyor, and the detection end of the color sensor faces the front surface of the lower facing paper. The color sensor is used to detect the printed pattern on the front surface of the lower facing paper. The controller calculates the linear speed of the lower facing paper based on the interval time between the appearances of two adjacent printed patterns to adjust the conveying speed of the belt conveyor.

[0015] On the other hand, the coating device further includes a second lower facing paper aligner, and the coating member and the spray guns are arranged between the lower facing paper aligner and the second lower facing paper aligner.

[0016] The present application has the following beneficial effects compared with the prior art:

[0017] A surface online film-forming system for gypsum board is provided. An alkali solution mixed with methylhydrogen siloxane is coated on the front surface of the lower facing paper. There are multiple chemically active Si-H groups in the methylhydrogen siloxane. Then, the wet gypsum board is dried. During the process of drying the gypsum board with the lower facing paper under alkaline conditions, the unhydrolyzed Si-H continues to hydrolyze with the water molecules evaporated from the board core to form Si-OH. Part of the Si-OH combines with the fiber of the facing paper to fix the hydrophobic group to the front surface of the gypsum board, and the other part of the Si-OH forms a more stable -Si-O- covalent network through self-condensation and covers the front surface of the gypsum board, so that a hydrophobic film is formed on the front surface of the gypsum board. Description of the Drawings

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0019] Figure 1 Stereogram of the coating device according to an embodiment of the present invention;

[0020] Figure 2 Bottom view of the coating device according to an embodiment of the present invention;

[0021] Figure 3 For Figure 2 Cross-sectional view in the A-A direction of, and enlarged view of the partial structure of;

[0022] The reference numerals in the figure are respectively represented as follows:

[0023] 1 - Lower facing paper; 11 - Blank area; 2 - Coating component; 21 - Rag; 22 - Elastic plate; 3 - Spray gun; 31 - Solenoid valve; 4 - Servo slide; 5 - Pipeline; 6 - Belt conveyor; 7 - Color sensor. Specific embodiments

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] The following provides an on-line film-forming system on the surface of gypsum board, including a coating device and a dryer; the method it executes includes the following steps: before drying the gypsum board, apply an alkaline solution mixed with methyl hydrogen silicone oil on the front side of the lower facing paper 1, and then dry the gypsum board.

[0026] The hydrophobic film is formed through the following principle:

[0027] The alkaline solution can use potassium hydroxide. Methyl hydrogen silicone oil is a highly polymerized organic compound, and there are multiple chemically active Si-H groups in its molecules. During the process of drying the gypsum board under alkaline conditions, the unhydrolyzed Si-H continues to hydrolyze with the water molecules evaporated from the board core to form Si-OH. Part of the Si-OH combines with the facing paper fibers to fix the hydrophobic groups on the front side of the gypsum board, and the other Si-OH forms a more stable -Si-O- covalent network through self-condensation and covers the front side of the gypsum board, finally forming a hydrophobic film on the front side of the gypsum board.

[0028] It can be seen that no other steps of the method for producing gypsum boards need to be changed. It is only necessary to add a coating device before the dryer of the gypsum board to coat the front side of the lower facing paper 1 with an alkaline solution mixed with methyl hydrogen silicone oil, and then a gypsum board with a hydrophobic film formed on the front side can be obtained.

[0029] Preferably:

[0030] Before the lower facing paper 1 passes through the lower facing paper scoring machine, coat the front side of the lower facing paper 1 with an alkaline solution mixed with methyl hydrogen silicone oil.

[0031] The position for coating the alkaline solution mixed with methyl hydrogen silicone oil is selected between the lower facing paper aligning machine and the lower facing paper scoring machine on the gypsum board production line. This is because it is difficult to coat the alkaline solution at the scored part of the lower facing paper 1, and it is difficult to form a hydrophobic layer at the edge of the lower facing paper 1 of the finally obtained gypsum board. Therefore, it is necessary to coat the alkaline solution before scoring, so that hydrophobic layers can be formed on both sides of the scored part of the lower facing paper 1.

[0032] Furthermore, since the top surface of the turned-up edge after the upper facing paper stands up needs to be coated with glue so that the upper facing paper can be pasted on the top surface of the turned-up edge, the edges on both sides of the upper facing paper cannot be coated with the alkaline solution, otherwise it will reduce the adhesiveness of the glue to the front side of the lower facing paper 1.

[0033] In the step of coating the front side of the lower facing paper 1 with an alkaline solution mixed with methyl hydrogen silicone oil, the following conditions also need to be specified:

[0034] Leave blank areas 11 with a width of 10 mm to 15 mm on both sides of the lower facing paper 1, and coat the alkaline solution mixed with methyl hydrogen silicone oil on the parts outside the blank areas 11.

[0035] Since the offset of the lower facing paper 1 during transmission will make it difficult to control the position of the blank areas 11, the following conditions also need to be specified: After the lower facing paper 1 passes through the lower facing paper aligning machine, coat the front side of the lower facing paper 1 with an alkaline solution mixed with methyl hydrogen silicone oil.

[0036] Furthermore, since the widths of the lower facing papers 1 of gypsum boards of different specifications are different, coating devices with different widths need to be prepared for the lower facing papers 1 with different widths.

[0037] The coating device includes at least two coating components 2, and the coating components 2 are arranged on the transmission path of the lower facing paper 1 and are used for coating the alkaline solution on the front side of the lower facing paper 1;

[0038] Two spreading members 2 can move along the width direction of the lower facing paper 1 so that the edges of the spreading members 2 can approach one side of the lower facing paper 1 and be away from the other side of the lower facing paper 1. The projections of the two spreading members 2 in the width direction of the lower facing paper 1 are staggered from each other, and the projections of the two spreading members 2 in the length direction of the lower facing paper 1 are partially overlapped, so that the two spreading members 2 can respectively spread from the middle of the lower facing paper 1 to one side of the lower facing paper 1 and repeatedly spread in the middle of the lower facing paper 1.

[0039] If the width of the gypsum board with the largest specification is twice or more the width of the gypsum board with the smallest specification, at this time, the two spreading members 2 are not sufficient to adapt to gypsum boards of any specification. The operator needs to replace the spreading members 2 with different lengths to adapt to the change in the width of the gypsum board, or expand the number of spreading members 2 to three or more.

[0040] When the spreading device includes three spreading members 2, one of the spreading members 2 is fixed in the middle of the lower facing paper 1 and is symmetrical with respect to the center line of the lower facing paper 1, and the other two spreading members 2 are respectively located on both sides of this spreading member 2.

[0041] More embodiments can be derived from the above embodiments. For example:

[0042] The spreading device includes three spreading members 2; one of the spreading members 2 is fixed in the middle of the lower facing paper 1 and is symmetrical with respect to the center line of the lower facing paper 1; the other two spreading members 2 are respectively located on both sides of this spreading member 2, and both of these two spreading members 2 can move along the width direction of the lower facing paper 1, and the projections in the width direction of the lower facing paper 1 are overlapped with each other.

[0043] Therefore, in many embodiments, the spreading member 2 only needs to meet the following conditions:

[0044] The overall width of the multiple spreading members 2 in the width direction of the lower facing paper 1 is adjustable, and the multiple spreading members 2 do not interfere with each other when adjusting the overall width.

[0045] The spreading member 2 can adopt existing tools such as a rag 21, a brush, a roller brush, a spray gun 3, etc. for applying liquid to the surface of the product. The alkaline solution can be quantitatively transported to the rag 21, the brush, the roller brush or the spray gun 3 through a pipeline.

[0046] The following preferred technical means are adopted in this embodiment.

[0047] The spreading device includes: a spray gun 3 and a linear driver;

[0048] A plurality of spray guns 3 are arranged side by side at equal intervals along the width direction of the lower facing paper 1. Each spray gun 3 is connected to an alkali solution source, and each spray gun 3 can be independently opened to spray alkali solution onto the surface of the lower facing paper 1;

[0049] The number of linear drivers is at least two. Two linear drivers are respectively connected to one application member 2. The driving direction of the linear driver is parallel to the width direction of the lower facing paper 1. When the number of application members 2 is three, the application member 2 located in the middle does not require the drive of the linear driver.

[0050] Specifically, the linear driver adopts a servo slide 4.

[0051] Each spray gun 3 is connected to a pipeline 5 with flowing alkali solution through a separate solenoid valve 31. The alkali solution can be stored inside a box (not shown in the figure). This box is connected to the pipeline 5 and is located at a high position, so that the pipeline 5 has a pressure that enables the alkali solution to be sprayed out through the spray gun 3.

[0052] The application member 2 includes: a rag 21 and an elastic plate 22; the rag 21 is fixedly connected to the elastic plate 22. The part where the elastic plate 22 is connected to the rag 21 is rectangular, and the edge of the rag 21 extends beyond the edge of the elastic plate 22. The rag 21 always adheres to the surface of the lower facing paper 1 under the action of the resilience of the elastic plate 22.

[0053] When the size of the gypsum board changes, the solenoid valve 31 selectively opens and closes to change the spraying width of the spray gun 3. At the same time, the servo slide 4 drives the elastic plate 22 to move, so that after the alkali solution sprayed by the spray gun 3 is leveled by the rag 21, it just covers the part outside the blank areas 11 on both sides of the lower facing paper 1.

[0054] Furthermore, since at least two application members 2 are asymmetric with respect to the center line of the lower facing paper 1, when each application member 2 applies alkali solution to the front side of the lower facing paper 1, it will cause the lower facing paper 1 to deflect towards one side, resulting in the deflected lower facing paper 1 shifting again.

[0055] To solve this problem, a device that can prevent the application member 2 from applying a force that causes the lower facing paper 1 to shift is required, or a lower facing paper deviation rectifier (not shown in the figure) is added between the coating device and the lower facing paper scoring machine.

[0056] Among them, the device that can prevent the application member 2 from applying a force that causes the lower facing paper 1 to shift includes: a support member. The support member is arranged on the side of the lower facing paper 1 facing away from the application member 2. The support member is used to support the back of the lower facing paper 1, so that when the application member 2 applies a force to the front side of the lower facing paper 1, the support member applies a reverse force, and the two forces cancel each other out to prevent the lower facing paper 1 from shifting.

[0057] The supporting member can adopt existing technical means such as roller shafts and smooth metal plates that will not damage the back surface of the lower facing paper 1 when rubbing against the back surface of the lower facing paper 1.

[0058] The following preferred technical means are adopted in this embodiment.

[0059] The device for preventing the coating member 2 from applying a force to the lower facing paper 1 to cause it to shift includes: a belt conveyor 6, the conveying surface of the belt conveyor 6 is attached to the back surface of the lower facing paper 1, the conveying speed of the belt conveyor 6 is in the same direction and at the same speed as the linear speed of the lower facing paper 1, and the width of the conveying surface of the belt conveyor 6 is greater than the width of the lower facing paper 1.

[0060] Further, in order to ensure that the conveying speed of the belt conveyor 6 is the same as the linear speed of the lower facing paper 1, in this embodiment, the linear speed of the lower facing paper 1 is also detected by a color sensor 7. The color sensor 7 is installed between the lower facing paper alignment machine and the belt conveyor 6, and the detection end of the color sensor 7 faces the front surface of the lower facing paper 1. The color sensor 7 is used to detect the printed pattern on the front surface of the lower facing paper 1.

[0061] The printed pattern is printed on the surface of the lower facing paper 1 by a printing roller before the lower facing paper 1 passes through the alignment machine. Usually, the printed pattern is the manufacturer's name, specification, and batch number of the gypsum board. Usually, the color sensor 7 is set in the middle of the lower facing paper 1, and the sensed color is black.

[0062] The controller calculates the linear speed of the lower facing paper 1 according to the interval time between the appearances of two adjacent printed patterns, and then adjusts the conveying speed of the belt conveyor 6 so that the conveying speed of the belt conveyor 6 is equal to the linear speed of the lower facing paper 1. There is no relative movement between the conveying surface of the belt conveyor 6 and the lower facing paper 1, and thus no relative friction will be generated.

[0063] The operator can also use an optical encoder to replace the color sensor 7. The optical encoder is used to detect the rotational speed of the roller shaft for conveying the lower facing paper 1, and then the linear speed of the lower facing paper 1 is calculated by the controller. However, this calculation result is not accurate, and there is a problem of slipping between the lower facing paper 1 and the roller shaft.

[0064] The above embodiments are only exemplary embodiments of the present invention and are not used to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present invention. Such modifications or equivalent replacements should also be regarded as falling within the protection scope of the embodiments of the present invention.

Claims

1. An online film-forming system for the surface of a gypsum board, characterized in that: include: Application devices and dryers; The dryer is used for drying wet gypsum board; The coating device is used to coat the front surface of the lower face paper with an alkaline solution mixed with methyl hydrogen silicone oil before the wet gypsum board is dried; The coating device is arranged before the lower face paper scoring machine and after the lower face paper deviation correcting machine of the gypsum board production line; The coating device comprises a coating component (2) and a spray gun (3); The smearing component (2) and the spray gun (3) are both arranged on the transmission path of the lower face paper, the spray gun (3) is connected to an alkali solution source and is used to spray an alkali solution mixed with methyl hydrogen silicone oil onto the surface of the lower face paper, and the smearing component (2) is used to smooth the alkali solution on the front side of the lower face paper; The number of the smearing components (2) is at least 2, and the plurality of smearing components (2) form a continuous and uninterrupted smearing area in the width direction of the lower face paper, wherein the position of at least one of the smearing components (2) in the width direction of the lower face paper can be adjusted to change the overall width of the smearing area; The coating device further comprises a belt conveyor (6), wherein the belt conveyor (6) is arranged on a side of the lower protective paper facing away from the coating component (2), the transmission surface of the belt conveyor (6) is in contact with and supports the back side of the lower protective paper to offset the force applied by the coating component (2) to the front side of the lower protective paper, the transmission speed of the belt conveyor (6) is in the same direction and at the same speed as the linear speed of the lower protective paper, and the width of the transmission surface of the belt conveyor (6) is greater than the width of the lower protective paper.

2. The online film-forming system for the surface of gypsum board according to claim 1, characterized in that: The number of the spray guns (3) is several, and the several spray guns (3) are arranged side by side at equal intervals along the width direction of the lower face paper, and each of the spray guns (3) can be opened or closed independently.

3. The online film-forming system for the surface of gypsum board according to claim 1, characterized in that: The coating device further comprises a color sensor (7) and a controller. The color sensor (7) is installed between the lower face paper deflection correction machine and the belt conveyor (6), and the detection end of the color sensor (7) faces the front side of the lower face paper. The color sensor (7) is used to detect the printed pattern on the front side of the lower face paper. The controller calculates the linear speed of the lower face paper according to the interval time between two adjacent printed patterns to adjust the transmission speed of the belt conveyor (6).

4. The online film-forming system for the surface of gypsum board according to claim 1, characterized in that: The coating device also includes a second lower face paper deflection corrector, and the coating component (2) and the spray gun (3) are arranged between the lower face paper deflection corrector and the second lower face paper deflection corrector.

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