CN115837347A

CN115837347A - Circuit board and coating process thereof

Info

Publication number: CN115837347A
Application number: CN202210042702.0A
Authority: CN
Inventors: 焦晓飞
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-01-14
Filing date: 2022-01-14
Publication date: 2023-03-24

Abstract

The invention relates to a circuit board and a coating process thereof. A coating process for a circuit board comprising: coating a paint layer on the surface of the substrate and curing the paint layer; and coating a waterproof layer on the surface of the paint layer opposite to the substrate, and solidifying the waterproof layer. According to the circuit board and the coating process thereof, the surface of the circuit board is covered with the double-layer coating, and the paint layer contains hydrophobic groups, so that moisture in the external environment can be prevented from permeating the paint layer and entering the substrate, and a moisture-proof effect is achieved; the surface covering of lacquer layer has the waterproof layer, and the waterproof layer can prevent effectively that the bright water among the external environment from permeating lacquer the layer, effectively keeps apart the hydrone outside lacquer the layer, plays dampproofing and waterproof dual function, is favorable to improving the dampproofing and waterproofing performance of circuit board.

Description

Circuit board and coating process thereof

Technical Field

The invention relates to the technical field of circuit boards, in particular to a circuit board and a coating process thereof.

Background

The circuit board is a carrier for electrically connecting electronic components with other assemblies, and is widely applied to electronic products such as electronic communication equipment, electronic computers, household appliances and the like. When the electronic product is used in a humid environment, the internal components of the electronic product can be affected with damp and damaged, particularly, the circuit board with a precise structure has poor resistance to water vapor, once the electronic product enters water or is affected with damp, a thick water molecule film is formed on the surface of the circuit board, the insulation resistance of the circuit board is greatly reduced, short circuit is caused, and the quality of the product is seriously affected.

Disclosure of Invention

In view of the above, it is necessary to provide a circuit board and a coating process thereof to solve the problem of poor waterproof performance of the existing circuit board.

A circuit board comprises a substrate, a paint layer and a waterproof layer, wherein the paint layer covers the surface of the substrate, and the waterproof layer covers the surface of the paint layer, which is back to the substrate. In the circuit board, the surface of the circuit board is covered with the double-layer coating, and the paint layer contains hydrophobic groups, so that moisture in the external environment can be prevented from permeating the paint layer and entering the substrate, and a moisture-proof effect is achieved; the surface covering of lacquer layer has the waterproof layer, and the waterproof layer can prevent effectively that the bright water among the external environment from permeating lacquer the layer, effectively keeps apart the hydrone outside lacquer the layer, plays dampproofing and waterproof dual function, is favorable to improving the dampproofing and waterproofing performance of circuit board.

In one embodiment, the thickness of the lacquer layer is in the range of 100 μm 20 μm. Through this setting, can effectively prevent the moisture infiltration base plate among the external environment, compromise the heat dispersion of base plate simultaneously, be favorable to improving the life of base plate.

In one embodiment, the thickness of the waterproof layer ranges from 2.0mm to 2.5mm. Through the arrangement, the defect that only a single-layer coating of the paint layer has poor waterproof performance is overcome through the waterproof layer covered on the surface of the paint layer; the paint coating can effectively prevent the clear water in the external environment from permeating into the paint layer, and simultaneously, the heat dissipation performance of the substrate is taken into consideration, thereby being beneficial to prolonging the service life of the substrate.

In one embodiment, the paint layer and the waterproof layer are transparent. Through this setting, make the base plate surface visual when making the base plate have dampproofing waterproof performance, be convenient for observe the electronic components on base plate surface, avoid sheltering from the base plate because of lacquer layer and waterproof layer.

In one embodiment, the paint layer is a three-proofing paint, and the waterproof layer is silicone adhesive. Through this setting, can make the circuit board have better dampproofing and waterproof performance, and be difficult for causing stress damage to the base plate.

A coating process of a circuit board comprises the following steps: coating a paint layer on the surface of the substrate and curing the paint layer; and coating a waterproof layer on the surface of the paint layer opposite to the substrate, and solidifying the waterproof layer. According to the coating process of the circuit board, the surface of the circuit board is covered with the double-layer coating, and the paint layer contains hydrophobic groups, so that moisture in the external environment can be prevented from permeating the paint layer and entering the substrate, and a moisture-proof effect is achieved; the surface covering of lacquer layer has the waterproof layer, and the waterproof layer can prevent effectively that the bright water among the external environment from permeating lacquer the layer, effectively keeps apart the hydrone outside lacquer the layer, plays dampproofing and waterproof dual function, is favorable to improving the dampproofing and waterproofing performance of circuit board.

In one embodiment, before the step of coating the surface of the substrate with the paint layer and curing the paint layer, the method further comprises the following steps: and acquiring first coating parameters of the paint layer, and setting the first coating parameters on first coating equipment. Through the step, the first coating equipment can uniformly coat the paint layer on the surface of the substrate, and the coating uniformity of the paint layer is facilitated.

In one embodiment, the first coating parameter comprises a thickness range of the paint layer, which is obtained by applying different thicknesses of the paint layer on the template and performing a comparative test. Through the step, the first coating equipment can uniformly coat the paint layer on the surface of the substrate, and the coating uniformity of the paint layer is facilitated.

In one embodiment, the step of applying a paint layer on the surface of the substrate and curing the paint layer comprises: uniformly coating a paint layer on the first surface of the substrate through first coating equipment, and curing the paint layer; and uniformly coating a paint layer on the second surface of the substrate by the first coating equipment, and curing the paint layer, wherein the second surface and the first surface are positioned on different sides of the substrate. Through this step, through at first surface and second surface coating lacquer layer respectively, can make the surface of base plate by the parcel of lacquer layer, be favorable to improving the humidity resistance of base plate.

In one embodiment, the step of applying a paint layer on the surface of the substrate and curing the paint layer further comprises: the paint layer was cured by room temperature for 7 days or by heating for 15 minutes. Through the step, the paint layer can be tightly adhered to the surface of the substrate, and the subsequent coating process is prevented from being influenced by incomplete curing of the paint layer.

In one embodiment, before the step of applying the waterproof layer on the surface of the paint layer opposite to the substrate and curing the waterproof layer, the method further comprises the following steps: and eliminating bubbles in the waterproof layer and enabling the bubbles in the waterproof layer to reach a preset limit value. Through this step, before waterproof layer coating to lacquer layer surface, can effectively reduce the production of the bubble in the waterproof layer, prevent the influence of bubble to the coating homogeneity of waterproof layer, improve the water-proof effects of waterproof layer to can effectually protect the circuit board.

In one embodiment, the method comprises the following steps: the waterproof layer is accommodated in the container, the container is positioned in the closed space and vacuumized, and the container is rotated centrifugally until bubbles in the waterproof layer reach a preset limit value, and vacuumizing and centrifugally rotating the container are stopped; the container was inverted and left to stand. Through the step, the bubbles in the waterproof layer are removed through centrifugal vacuumizing and waterproofing, and the bubbles are prevented from being further generated in a standing mode after the completion, so that the bubbles in the waterproof layer are effectively reduced.

In one embodiment, after the step of eliminating the bubbles in the waterproof layer and making the bubbles in the waterproof layer reach the preset limit value, the method further includes the following steps: and acquiring second coating parameters of the waterproof layer, and setting the second coating parameters on second coating equipment. Through the step, the second coating equipment can uniformly coat the waterproof layer on the surface of the paint layer, and the coating uniformity of the waterproof layer is facilitated.

In one embodiment, the second coating parameter includes a thickness range of the waterproof layer, and the thickness range of the paint layer is obtained by coating the template with paint layers of different thicknesses and performing a comparative test. Through this step, can make second coating equipment evenly coat the surface of waterproof layer on the lacquer layer, be favorable to the coating uniformity of waterproof layer.

In one embodiment, the step of coating a waterproof layer on the surface of the paint layer opposite to the substrate and curing the waterproof layer comprises: obtaining a coating area; setting a second coating parameter; planning a coating path according to the second coating parameter; and controlling the second coating equipment to move on the coating path and coating the waterproof layer. Through the step, the waterproof layer can be uniformly coated on the surface of the paint layer, and the phenomenon that the waterproof layer is unevenly distributed on the surface of the paint layer is avoided.

In one embodiment, the waterproof layer is cured by room temperature for 24 to 48 hours. By this step, the waterproof layer can be tightly bonded to the surface of the substrate.

Drawings

FIG. 1 is a schematic diagram of a circuit board according to an embodiment;

FIG. 2 is a schematic view illustrating a coating process of a circuit board according to an embodiment.

Reference numerals: 100. a substrate; 200. a paint layer; 300. and a waterproof layer.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are merely used to more clearly illustrate the technical solutions of the present application, and therefore are only examples, and the protection scope of the present application is not limited thereby.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present application, the technical terms "first", "second", and the like are used only for distinguishing different objects, and are not to be construed as indicating or implying relative importance or to implicitly indicate the number, specific order, or primary-secondary relationship of the technical features indicated. In the description of the embodiments of the present application, "a plurality" means two or more unless specifically defined otherwise.

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 in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is only one kind of association relationship describing an associated object, and means that three relationships may exist, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two), and similarly, "plural sets" refers to two or more (including two), and "plural pieces" refers to two or more (including two).

In the description of the embodiments of the present application, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships that are based on the orientations and positional relationships shown in the drawings, and are used for convenience in describing the embodiments of the present application and for simplification of the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are used in a broad sense, and for example, may be fixedly connected, detachably connected, or integrated; mechanical connection or electrical connection is also possible; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the embodiments of the present application can be understood by those of ordinary skill in the art according to specific situations.

In order to achieve the purpose of water proofing or moisture proofing, some schemes adopt various waterproof structures added in the structural design of electronic products to avoid the invasion of water vapor. However, the above arrangement makes the electronic product have a complex structure and high design and manufacturing requirements, so that the production cost cannot be reduced.

Based on the consideration, through intensive research, a circuit board with high waterproof and moistureproof performances and a coating process thereof are designed.

As shown in fig. 1, the circuit board in one embodiment includes a substrate 100, a paint layer 200 and a waterproof layer 300, wherein the paint layer 200 covers a surface of the substrate 100, and the waterproof layer 300 covers a surface of the paint layer 200 opposite to the substrate 100.

Through the arrangement, the surface of the circuit board is covered with the double-layer coating, the paint layer 200 contains hydrophobic groups, so that moisture in the external environment can be prevented from permeating the paint layer 200 and entering the substrate 100, and a moisture-proof effect is achieved; the surface of lacquer layer 200 covers has waterproof layer 300, and waterproof layer 300 can prevent effectively that the bright water among the external environment from permeating lacquer layer 200, effectively keeps apart the hydrone outside lacquer layer 200, plays dampproofing and waterproof dual function, is favorable to improving the dampproofing and waterproofing performance of circuit board.

It should be noted that the circuit board may be a rigid circuit board or a flexible circuit board, and may also be a single-sided circuit board, a double-sided circuit board, or a multi-layer circuit board. The shape and thickness of the circuit board may be designed according to actual use requirements, and are not specifically limited herein.

In a specific embodiment, the circuit board is a carrier for electrically connecting electronic components with other components, and after various types of electronic components, such as capacitors, resistors, triodes, and other chip components that realize various functions, are disposed on the surface of the substrate 100, the surface of the substrate 100 is covered with the paint layer 200 and the waterproof layer 300. The shape and thickness of the substrate 100 may be designed according to the actual use requirement, and are not limited in detail. For example, the substrate 100 may be rectangular, circular, or other shapes.

Specifically, the substrate 100 may include a substrate and at least one conductive layer, wherein the conductive layer is formed on one surface of the substrate by pressing or bonding. For example, the base material has a first surface and a second surface opposite to the first surface, and the first surface and the second surface are both formed with conductive layers, so as to obtain a substrate 100 with both sides covered with conductive layers. Alternatively, a conductive layer is formed only on the first surface or the second surface of the base material, thereby obtaining a substrate 100 with a single surface covered with the conductive layer.

In a specific embodiment, the conductive layer is a copper foil.

In a specific embodiment, the substrate 100 includes a first surface and a second surface opposite to each other, the first surface and the second surface are covered with the paint layer 200, a surface of the paint layer 200 of the first surface facing away from the substrate 100 is covered with the waterproof layer 300, and a surface of the paint layer 200 of the second surface facing away from the substrate 100 is covered with the waterproof layer 300.

In the embodiment shown in fig. 1, the thickness of the lacquer layer 200 is in the range of 100 μm ± 20 μm.

It can be understood that, if the paint layer 200 covered on the surface of the substrate 100 is too thin, the substrate 100 is very exposed after the paint layer 200 is peeled off, and moisture in the external environment is very easy to permeate into the substrate 100, which results in poor moisture resistance; if the paint layer 200 covering the surface of the substrate 100 is too thick, the substrate 100 dissipates heat slowly during use, and thus the heat dissipation performance is poor.

Through the above arrangement, the thickness range of the paint layer 200 is preferably 100 μm ± 20 μm, which can effectively prevent moisture in the external environment from permeating into the substrate 100, and simultaneously, the heat dissipation performance of the substrate 100 is considered, which is beneficial to improving the service life of the substrate 100.

In the present embodiment, the thickness range of the paint layer 200 is obtained by a comparative test after the stencil is coated with the paint layer 200 of different thickness. In other embodiments, the thickness range of the paint layer 200 may be other value ranges, and can be set according to actual use requirements.

In the embodiment shown in fig. 1, the waterproof layer 300 has a thickness ranging from 2.0mm to 2.5mm.

It can be understood that, if the waterproof layer 300 covered on the surface of the paint layer 200 is too thin, the paint layer 200 is easily exposed after the waterproof layer 300 is peeled off, and the open water in the external environment easily penetrates into the paint layer 200 and enters the substrate 100, at this time, the waterproof performance is poor; if the waterproof layer 300 covered on the surface of the paint layer 200 is too thick, the heat cannot be dissipated quickly in the using process, and the heat dissipation performance is poor.

Through the arrangement, the thickness range of the waterproof layer 300 is preferably 2.0 mm-2.5 mm, and the defect that only a single-layer coating of the paint layer 200 is poor in waterproof performance is overcome by covering the waterproof layer 300 on the surface of the paint layer 200; the transparent water in the external environment is effectively prevented from permeating into the paint layer 200, and the heat dissipation performance of the substrate 100 is taken into consideration, which is beneficial to improving the service life of the substrate 100.

In the present embodiment, the range of the thickness of the waterproof layer 300 is obtained by a comparative test after the waterproof layer 300 of different thickness is coated on the form. In other embodiments, the thickness range of the waterproof layer 300 may be other value ranges, and may be set according to actual use requirements.

In the embodiment shown in fig. 1, both the paint layer 200 and the waterproof layer 300 are transparent.

It can be understood that, if the paint layer 200 and the waterproof layer 300 are not transparent, the surface of the substrate 100 covered with the paint layer 200 and the waterproof layer 300 is not visible, and the circuit pattern on the surface of the substrate 100 cannot be seen, which may affect the subsequent electrical connection with each electronic component.

Through the arrangement, the substrate 100 has the moisture-proof and waterproof properties, and the surface of the substrate 100 is visible, so that the electronic components on the surface of the substrate 100 can be observed conveniently, and the substrate 100 is prevented from being shielded by the paint layer 200 and the waterproof layer 300.

In this embodiment, as shown in fig. 1, the paint layer 200 is a three-proof paint, and the waterproof layer 300 is a silicone adhesive.

It can be understood that if the hardness of the paint layer 200 and the waterproof layer 300 is too high, stress damage may occur on the surface of the substrate 100 after the paint layer 200 and the waterproof layer 300 are cured, and the surface of the substrate 100 may be damaged and may not be used normally. Through the arrangement, the circuit board has better moisture-proof and waterproof performances, and stress damage to the substrate 100 is not easy to cause.

In a specific embodiment, the chemical component of the three-proofing paint is at least one of acrylate, silicone and polyurethane. The three-proofing paint has good high and low temperature resistance, can form a layer of transparent film after being cured, can effectively protect the substrate 100, and plays a good role in moisture prevention.

In a specific embodiment, the chemical component of the silicone adhesive is at least one of polydimethylsiloxane and silicon dioxide. The silicone adhesive has low hardness and high viscosity at normal temperature and normal pressure, and can form a layer of rubber solid protective film after being cured, and the protective film can be tightly adhered to the surface of the three-proofing paint. The silicone adhesive and the three-proofing paint are not easy to delaminate and crack in the long-term use process, and the substrate 100 is not easy to cause stress damage due to low hardness after the silicone adhesive is cured.

In other embodiments, the paint layer 200 may be other types of moisture-proof paint, and the waterproof layer 300 may be other types of waterproof paint or glue.

Referring to fig. 2, an embodiment of a coating process of a circuit board includes the following steps:

s1, coating a paint layer 200 on the surface of a substrate 100, and curing the paint layer 200;

and S2, coating a waterproof layer 300 on the surface of the paint layer 200 opposite to the substrate 100, and curing the waterproof layer 300.

Through the steps, the surface of the circuit board is covered with the double-layer coating, the paint layer 200 contains hydrophobic groups, moisture in the external environment can be prevented from permeating the paint layer 200 and entering the substrate 100, and a moisture-proof effect is achieved; the surface of lacquer layer 200 covers has waterproof layer 300, and waterproof layer 300 can prevent effectively that the bright water among the external environment from permeating lacquer layer 200, effectively keeps apart the hydrone outside lacquer layer 200, plays dampproofing and waterproof dual function, is favorable to improving the dampproofing and waterproofing performance of circuit board.

It should be noted that the circuit board may be a rigid circuit board or a flexible circuit board, and may also be a single-sided circuit board, a double-sided circuit board, or a multilayer circuit board. The shape and thickness of the circuit board may be designed according to actual use requirements, and are not specifically limited herein.

In a specific embodiment, the circuit board is a carrier for electrically connecting electronic components with other components, and various types of electronic components, such as capacitors, resistors, triodes, and other chip components for implementing various functions, may be disposed on the surface of the substrate 100. The shape and thickness of the substrate 100 may be designed according to actual use requirements, and are not limited in detail. For example, the substrate 100 may be rectangular, circular, or other shapes.

In a specific embodiment, the conductive layer is a copper foil.

In the embodiment shown in fig. 2, before the step S1 of coating the surface of the substrate 100 with the paint layer 200 and curing the paint layer 200, the following step S12 is further included:

s12, acquiring a first coating parameter of the paint layer 200, and setting the first coating parameter on first coating equipment.

Through the steps, the first coating device can uniformly coat the paint layer 200 on the surface of the substrate 100, which is beneficial to the coating uniformity of the paint layer 200.

Specifically, the first coating parameter includes a thickness range of the paint layer 200, and the thickness range of the paint layer 200 is obtained by coating the paint layer 200 of different thickness on the stencil and performing a comparative test.

For example, a plurality of comparative tests are provided, in which the template types and parameters are identical, and only the thickness of the paint layer 200 covering the template is different. The optimum thickness range of the paint layer 200 is obtained by performing a life test, a use environment test, and an impact test.

Here, the template is a metal template, the surface of the template is smooth, and no electronic component is disposed on the template.

In the present embodiment, the thickness range of the paint layer 200 is preferably 100 μm ± 20 μm. Moisture in the external environment can be effectively prevented from permeating into the substrate 100, and the heat dissipation performance of the substrate 100 is also considered, which is beneficial to prolonging the service life of the substrate 100. In other embodiments, the thickness range of the paint layer 200 may be other value ranges to meet the actual use requirement.

In this embodiment, as shown in fig. 2, the first coating parameter includes parameters such as a coating speed, a coating pressure, and a coating path, in addition to the thickness range of the paint layer 200.

In the embodiment shown in fig. 2, in the step S1 of coating the surface of the substrate 100 with the paint layer 200 and curing the paint layer 200, the method further includes the steps of:

s13, uniformly coating the paint layer 200 on the first surface of the substrate 100 through first coating equipment, and curing the paint layer 200;

and S14, uniformly coating the paint layer 200 on a second surface of the substrate 100 through the first coating device, and curing the paint layer 200, wherein the second surface and the first surface are positioned on different sides of the substrate 100.

It can be understood that the substrate 100 has a first surface and a second surface opposite to each other, and the first surface and the second surface are coated with the paint layer 200 respectively, so that the surface of the substrate 100 can be wrapped by the paint layer 200, which is beneficial to improving the moisture resistance of the substrate 100.

In the embodiment, the uniform coating of the paint layer 200 on the first surface of the substrate 100 and the uniform coating of the paint layer 200 on the second surface of the substrate 100 are sequentially performed. That is, the first surface of the substrate 100 may be uniformly coated with the paint layer 200 and the paint layer 200 may be cured, or the second surface of the substrate 100 may be uniformly coated with the paint layer 200 and the paint layer 200 may be cured.

In this embodiment, the paint layer 200 is uniformly applied to the first surface of the substrate 100 and the second surface of the substrate 100 by spraying or brushing.

In one embodiment, as shown in fig. 2, the first coating apparatus is a spray coater, and the paint layer 200 is uniformly sprayed on the first surface of the substrate 100 and the second surface of the substrate 100 through a nozzle of the spray coater.

For example, the substrate 100 is placed on a stage of a coating machine with the first surface facing upward, and the paint layer 200 is uniformly coated on the first surface of the substrate 100 by reciprocating the nozzle; after the paint layer 200 is cured on the first surface, the substrate 100 is turned over and the second surface is turned upward, the paint layer 200 is uniformly sprayed on the second surface of the substrate 100 by the nozzle moving in a reciprocating manner, and the paint layer 200 is cured on the second surface.

In another embodiment, the first coating apparatus is a sprayer, and the paint layer 200 is uniformly brushed onto the first surface of the substrate 100 and the second surface of the substrate 100 by a brush head of the sprayer.

For example, the substrate 100 is placed on a placing table of a spraying machine, the first surface of the substrate is upward, and the brush head moves back and forth to brush the paint layer 200 to the first surface of the substrate 100; after the paint layer 200 is cured on the first surface, the substrate 100 is turned over and the second surface is turned upward, the brush head is moved in a reciprocating manner to brush the paint layer 200 on the second surface of the substrate 100, and the paint layer 200 is cured on the second surface.

s15, curing the paint layer 200 for 7 days at room temperature or 15 minutes by heating.

Through the above steps, the paint layer 200 can be tightly adhered to the surface of the substrate 100, and the subsequent coating process is prevented from being affected by incomplete curing of the paint layer 200.

In this embodiment, the paint layer 200 is cured at room temperature for 7 days or at heating for 15 minutes to enable the paint layer 200 to be tightly adhered to the surface of the substrate 100 due to the kind of the paint layer 200, the thickness of the paint layer 200, and the area of the paint layer 200. In other embodiments, when the types of the paint layers 200, the thickness of the paint layers 200, and the area size of the paint layers 200 are different, the time period for curing the paint layers 200 at room temperature or heating may also be adjusted according to actual conditions.

In a specific embodiment, the paint layer 200 is a three-proofing paint, and the chemical composition of the three-proofing paint is at least one of acrylate, silicone and polyurethane. The three-proofing paint has good high and low temperature resistance, can form a layer of transparent film after being cured, can effectively protect the substrate 100, and plays a good role in moisture prevention.

In the embodiment shown in fig. 2, before the step S2 of applying the waterproof layer 300 on the surface of the paint layer 200 opposite to the substrate 100 and curing the waterproof layer 300, the method further comprises the following steps:

and S21, eliminating the air bubbles in the waterproof layer 300 and enabling the air bubbles in the waterproof layer 300 to reach a preset limit value.

It is understood that if too many bubbles are formed in the waterproof layer 300, the coating uniformity of the waterproof layer 300 may be affected, and the waterproof layer 300 having too many bubbles may have a thinner thickness than the waterproof layer 300 having no bubbles, which may easily result in poor waterproof performance of the waterproof layer 300.

Through the above steps, before the waterproof layer 300 is coated on the surface of the paint layer 200, the generation of bubbles in the waterproof layer 300 can be effectively reduced, the influence of the bubbles on the coating uniformity of the waterproof layer 300 is prevented, the waterproof effect of the waterproof layer 300 is improved, and thus the circuit board can be effectively protected.

In this embodiment, as shown in fig. 2, step S21 specifically includes the following steps:

the waterproof layer 300 is accommodated in the container, the container is positioned in the closed space and vacuumized, and the container is centrifugally rotated until the bubbles in the waterproof layer 300 reach a preset limit value, and vacuumizing and centrifugally rotating the container are stopped;

the container was inverted and left to stand.

Through the steps, the air bubbles in the waterproof layer 300 are removed through centrifugal vacuumizing and waterproofing, and the air bubbles are prevented from being further generated in a standing mode after the air bubbles are removed, so that the air bubbles in the waterproof layer 300 are effectively reduced.

It should be noted here that the container is tubular, the second coating device has a centrifugal chamber, a closed space is provided in the centrifugal chamber, the container is placed in the centrifugal chamber for centrifugal rotation, the centrifugal chamber is vacuumized until the air bubbles in the waterproof layer 300 reach a preset limit value, the vacuumized and centrifugally rotated container is stopped, the container is inverted and stood after completion, the container after inversion and standing is directly transferred to the second coating device for coating, the waterproof layer 300 in the container does not need to be transferred to other placing cavities again, and the air bubbles in the waterproof layer 300 are prevented from being increased in the transferring process.

In this embodiment, the container is inverted and left to stand for 30 minutes. In other embodiments, the length of time that the container is inverted and left standing can be adjusted to the actual situation.

In this embodiment, the rate of centrifugal rotation of the vessel is 500 to 1000r/min. In other embodiments, the rate of centrifugal rotation of the container may also be other values.

In the embodiment shown in fig. 2, after step S21 of removing air bubbles in the waterproof layer 300 and making the air bubbles in the waterproof layer 300 reach a preset limit value, the method further includes the following steps:

and S22, acquiring second coating parameters of the waterproof layer 300, and setting the second coating parameters on second coating equipment.

Through the above steps, the second coating apparatus can uniformly coat the waterproof layer 300 on the surface of the paint layer 200, which is beneficial to the coating uniformity of the waterproof layer 300.

Specifically, the second coating parameter includes a thickness range of the waterproof layer 300, and the thickness range of the waterproof layer 300 is obtained by coating waterproof layers 300 of different thicknesses on a template and performing a comparative test.

For example, a plurality of comparison tests are provided, and the types and parameters of the templates in the comparison tests are consistent, and only the thickness of the waterproof layer 300 covered on the templates is different. The optimal thickness range of the waterproof layer 300 is obtained by comparing the size of the bubbles, the permeation time, and the permeation rate.

It should be noted here that the template is a metal template and has a smooth surface, and no electronic component is disposed on the template.

In the embodiment, the thickness range of the waterproof layer 300 is preferably 2.0 mm-2.5 mm, and the defect that only a single-layer coating of the paint layer 200 is poor in waterproof performance is overcome by covering the waterproof layer 300 on the surface of the paint layer 200; the transparent water in the external environment is effectively prevented from permeating into the paint layer 200, and the heat dissipation performance of the substrate 100 is taken into consideration, which is beneficial to improving the service life of the substrate 100. In other embodiments, the thickness range of the waterproof layer 300 may be other value ranges to meet the actual use requirement.

In this embodiment, as shown in fig. 2, the second coating parameters include parameters such as a coating speed, a coating pressure, and a coating path, in addition to the thickness range of the waterproof layer 300.

In the embodiment shown in fig. 2, the step of coating the waterproof layer 300 on the surface of the paint layer 200 opposite to the substrate 100 and curing the waterproof layer 300 includes the following step S23, where the step S23 is specifically:

obtaining a coating area;

setting a second coating parameter;

planning a coating path according to the second coating parameters;

the second coating apparatus is controlled to move on the coating path and coat the waterproof layer 300.

Through the above steps, the waterproof layer 300 can be uniformly coated on the surface of the paint layer 200 opposite to the substrate 100, and the waterproof layer 300 is prevented from being unevenly distributed on the surface of the paint layer 200 opposite to the substrate 100.

In a specific embodiment, the second coating device is a dispenser, and the dispensing valve of the dispenser is controlled to move on the coating path, so that the waterproof layer 300 is uniformly coated on the surface of the paint layer 200. The dispensing point of the dispensing valve can be in any shape, such as rectangle, convex character, ellipse, etc. The shapes can be spliced according to the coating precision requirement, for example, the dispensing point in one area is rectangular, and the dispensing point in the other area is oval.

In one embodiment, the specific position of the coating area may be located by a coordinate system in the computer, such that the position of the dispensing valve is controlled by the coordinate system in the computer, and the coating of the waterproof layer 300 is achieved by the movement of the dispensing valve. In other embodiments, there are multiple ways to obtain the coated area. For example, the position information input by the user through the input device is received, and the dispensing area is determined according to the position information. The user can directly select the frame or finely adjust the frame after selecting the frame, or directly input the coordinates by the keyboard.

In one embodiment, the coating path may be from top to bottom, from left to right, or from outside to inside. When the coating path is planned, if the waterproof layer 300 is required to be filled to the edge of the coating area, the distance from the center line of the coating path close to the edge of the coating area is matched with the size of the dispensing point, that is, the waterproof layer is just filled to the edge of the coating area.

For example, the coating path may be dispensing point by point in the transverse direction, and the dispensing points on the adjacent transverse paths are connected end to end, that is, the dispensing starts in the next row and the dispensing ends in the previous row are connected for dispensing, so that the coating time can be saved. In addition, the coating path can also be dispensing point by point in the longitudinal direction, and the dispensing points on the adjacent longitudinal paths are connected end to end.

In the embodiment shown in fig. 2, the step of coating the surface of the paint layer 200 opposite to the substrate 100 with the waterproof layer 300 and curing the waterproof layer 300 comprises the steps of:

s24, curing the waterproof layer 300 at room temperature for 24-48 hours.

It is understood that since the waterproof layer 300 contains chemical components, heat curing may affect the chemical components in the waterproof layer 300 and generate bubbles, and the waterproof layer 300 can be cured only by room temperature.

In this embodiment, the waterproof layer 300 is cured at room temperature for 24 to 48 hours to allow the waterproof layer 300 to be closely adhered to the surface of the substrate 100 due to the type of the waterproof layer 300, the thickness of the waterproof layer 300, and the area of the waterproof layer 300. In other embodiments, when the type of the waterproof layer 300, the thickness of the waterproof layer 300 and the area of the waterproof layer 300 are different, the time period of the room temperature curing or the heating curing of the waterproof layer 300 can be adjusted according to actual conditions.

In a specific embodiment, the chemical component of the silicone adhesive is at least one of polydimethylsiloxane and silicon dioxide. The silicone adhesive has low hardness and high viscosity at normal temperature and normal pressure, and can form a layer of rubber solid protective film after being cured, and the protective film can be tightly adhered to the surface of the three-proofing paint. The silicone adhesive and the three-proofing paint are not easy to delaminate and crack in the long-term use process, and the substrate 100 is not easy to be damaged by stress due to low hardness after the silicone adhesive is cured.

According to some embodiments of the present application, referring to fig. 2, the present application provides a circuit board including a substrate 100, a paint layer 200 and a waterproof layer 300, wherein the paint layer 200 covers a surface of the substrate 100, and the waterproof layer 300 covers a surface of the paint layer 200 facing away from the substrate 100. The thickness range of the paint layer 200 is 100 mu m +/-20 mu m, and the thickness range of the waterproof layer 300 is 2.0 mm-2.5 mm. The paint layer 200 is three-proofing paint, and the waterproof layer 300 is silicone adhesive.

According to some embodiments of the present application, referring to fig. 2, the present application provides a coating process of a circuit board, comprising the steps of: rinsing and drying the surface of the substrate 100 to remove the residual impurities on the surface of the substrate 100; acquiring a first coating parameter of the paint layer 200, and setting the first coating parameter on first coating equipment, wherein the first coating parameter comprises parameters such as coating speed, coating pressure and coating path besides the thickness range of the paint layer 200; uniformly coating the paint layer 200 on the first surface of the substrate 100 by a first coating apparatus and curing the paint layer 200, wherein the paint layer 200 is cured for 7 days by room temperature or for 15 minutes by heating; uniformly coating the paint layer 200 on a second surface of the substrate 100 by a first coating device and curing the paint layer 200, wherein the paint layer 200 is cured for 7 days by room temperature or for 15 minutes by heating, and the second surface and the first surface are positioned on different sides of the substrate 100; accommodating the waterproof layer 300 in a container, enabling the container to be in a closed space, vacuumizing, centrifugally rotating the container until bubbles in the waterproof layer 300 reach a preset limit value, stopping vacuumizing and centrifugally rotating the container, inverting the container, and standing for 30 minutes; acquiring second coating parameters of the waterproof layer 300, and setting the second coating parameters on second coating equipment, wherein the second coating parameters comprise the thickness range of the waterproof layer 300, and parameters such as coating speed, coating pressure, coating path and the like; acquiring a coating area, setting a second coating parameter, planning a coating path according to the second coating parameter, controlling a second coating device to move on the coating path, and coating a waterproof layer 300 on the surface of the paint layer 200 back to the substrate 100; the waterproof layer 300 is cured at room temperature for 24 to 48 hours.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present disclosure, and the present disclosure should be construed as being covered by the claims and the specification. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. The present application is not intended to be limited to the particular embodiments disclosed herein but is to cover all embodiments that may fall within the scope of the appended claims.

Claims

1. A circuit board, comprising:

a substrate (100);

a paint layer (200) covering the surface of the substrate (100);

and the waterproof layer (300) covers the surface of the paint layer (200) back to the substrate (100).

2. The circuit board according to claim 1, characterized in that the thickness of the lacquer layer (200) is in the range of 100 μm ± 20 μm.

3. The circuit board according to claim 1, wherein the waterproof layer (300) has a thickness ranging from 2.0mm to 2.5mm.

4. The circuit board according to claim 1, wherein the lacquer layer (200) and the waterproof layer (300) are transparent.

5. The circuit board according to claim 1, wherein the lacquer layer (200) is a three-proof lacquer and the water-proof layer (300) is a silicone adhesive.

6. A process for coating a circuit board, comprising:

coating a paint layer (200) on the surface of a substrate (100) and curing the paint layer (200);

coating a waterproof layer (300) on the surface of the paint layer (200) opposite to the substrate (100), and curing the waterproof layer (300).

7. The process for coating a circuit board according to claim 6, wherein the step of applying the paint layer (200) on the surface of the substrate (100) and curing the paint layer (200) is preceded by the steps of:

a first application parameter of the paint layer (200) is obtained, and the first application parameter is set on a first application device.

8. The process for coating a circuit board according to claim 7, wherein the first coating parameters comprise a thickness range of the lacquer layer (200), the thickness range of the lacquer layer (200) being obtained by applying different thicknesses of the lacquer layer (200) on a stencil and performing a comparative test.

9. The process for coating a circuit board according to claim 7, wherein the step of applying the paint layer (200) on the surface of the substrate (100) and curing the paint layer (200) comprises:

uniformly coating the paint layer (200) on the first surface of the substrate (100) by the first coating device, and curing the paint layer (200);

uniformly coating the paint layer (200) on a second surface of the substrate (100) by the first coating device, wherein the second surface is positioned on a different side of the substrate (100) from the first surface, and curing the paint layer (200).

10. The coating process of the circuit board according to claim 6, wherein in the step of applying the paint layer (200) on the surface of the substrate (100) and curing the paint layer (200), further comprising:

the paint layer (200) is cured by room temperature for 7 days or heating for 15 minutes.

11. The process for coating a circuit board according to claim 6, wherein the step of applying a water-repellent layer (300) on the surface of the lacquer layer (200) facing away from the substrate (100) and curing the water-repellent layer (300) is preceded by the steps of:

eliminating the air bubbles in the waterproof layer (300) and enabling the air bubbles in the waterproof layer (300) to reach a preset limit value.

12. The process for coating a circuit board according to claim 11, further comprising the steps of:

accommodating the waterproof layer (300) in a container, enabling the container to be in a closed space, vacuumizing, centrifugally rotating the container until bubbles in the waterproof layer (300) reach a preset limit value, and stopping vacuumizing and centrifugally rotating the container;

the container was inverted and left to stand.

13. The process for coating a circuit board according to claim 11, wherein the step of eliminating the air bubbles in the waterproof layer (300) and bringing the air bubbles in the waterproof layer (300) to a preset limit value is followed by the steps of:

and acquiring second coating parameters of the waterproof layer (300), and setting the second coating parameters on second coating equipment.

14. The process for coating a circuit board according to claim 13, wherein the second coating parameters comprise a thickness range of the waterproof layer (300), and the thickness range of the paint layer (200) is obtained by coating the paint layer (200) with different thicknesses on a template and performing a comparative test.

15. The process for coating a circuit board according to claim 13, wherein the step of applying a water-repellent layer (300) to the surface of the lacquer layer (200) facing away from the substrate (100) and curing the water-repellent layer (300) comprises:

obtaining a coating area;

setting the second coating parameter;

planning a coating path according to the second coating parameter;

controlling the second coating device to move on the coating path and coat the waterproof layer (300).

16. The process for coating a circuit board according to claim 11, wherein the waterproof layer (300) is cured by room temperature for 24 to 48 hours.