FPC surface treatment process

Abstract

The invention discloses an FPC (Flexible Printed Circuit) surface treatment method, which comprises the following steps: S1, preparing surface treatment liquid, and conveying the surface treatment liquid into a treatment tank; s2, immersing the FPC to be treated into the treatment tank containing the surface treatment liquid, and keeping the FPC in the surface treatment liquid for 30-50 seconds; s3, drying the FPC processed in the step S2, transplanting the FPC into an atmospheric pressure plasma cleaning machine, and carrying out atmospheric plasma processing on the surface; wherein the surface treatment liquid is an organic alkaline solution, the PH of the surface treatment liquid is 9.5-10.5, and the temperature of the treatment liquid in the treatment tank is controlled to be 49-55 DEG C. According to the invention, the surface of the FPC is subjected to infiltration cleaning treatment by adopting the organic alkali solution, so that the surface activity of the product can be improved, the surface of the product has better adhesive force, and compared with a box type plasma treatment mode, the cost can be greatly controlled, and meanwhile, the surface performance of the FPC is not reduced.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit boards, in particular to a FPC surface treatment process. Background Art

[0002] Flexible circuit board is a kind of highly reliable and extremely flexible printed circuit board made of polyimide or polyester film as the substrate. It is referred to as soft board or FPC. It has the characteristics of high wiring density, light weight and thin thickness. As the most basic electronic component in modern electronic equipment, FPC plays the role of connecting and carrying electronic components. The surface energy of FPC has an important influence on the pasting and assembly of the product, so the surface of the product needs to be treated before assembly.

[0003] The existing processing methods are: first, atmospheric plasma treatment, which only adds a plasma layer on the surface of the product. It can meet the surface energy requirements without high temperature, but after high temperature welding, the plasma fails. Second, box-type plasma equipment is used for treatment, using carbon tetrafluoride / argon / oxygen / nitrogen and other gases for ionization in a vacuum state to roughen the FPC surface and increase plasma. This operation is cumbersome and has low production efficiency.

[0004] Therefore, a FPC surface treatment process is proposed to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a FPC surface treatment process to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a FPC surface treatment process, comprising the following steps:

[0007] S1, preparing a surface treatment liquid, and conveying the surface treatment liquid into a treatment tank;

[0008] S2, immersing the FPC to be treated into a treatment tank containing a surface treatment liquid, and keeping the FPC in the surface treatment liquid for 30-50 seconds;

[0009] S3, drying the FPC after being processed in step "S2" and then transferring it into an atmospheric pressure plasma cleaning machine for surface atmospheric plasma treatment;

[0010] Wherein, the surface treatment liquid is an organic alkaline solution with a pH of 9.5-10.5, and the temperature of the treatment liquid in the treatment tank is controlled to be 49-55°C.

[0011] Preferably, the drying temperature of the FPC in step S3 is 40-55°C.

[0012] Preferably, the surface treatment liquid is heated in the treatment tank.

[0013] Preferably, the surface treatment liquid is heated before being transported to the treatment tank, and at this time, the temperature of the surface treatment liquid needs to be heated to 49.5-55.5°C.

[0014] Preferably, the treatment tank comprises a liquid inlet, a liquid outlet, a first opening and a second opening, the first opening and the second opening are arranged on the tank wall of the treatment tank, the first opening and the second opening are on the same horizontal line, wherein the surface treatment liquid is input from the liquid inlet and discharged from the liquid outlet, the first opening and the second opening, and the input amount of the surface treatment liquid is equal to the output amount of the liquid outlet, the first opening and the second opening.

[0015] Preferably, the FPC is transported through a horizontal conveyor line, and the horizontal conveyor line enters from the first opening and is output from the second opening.

[0016] Preferably, the surface treatment liquid needs to submerge the upper surface of the FPC located on the horizontal conveyor line body.

[0017] Preferably, the line speed of the horizontal conveyor line is set to 0.45-0.55 M / min.

[0018] Preferably, the surface treatment liquid comprises a saponifier, a catalyst and an activator.

[0019] Preferably, the saponifier is triethanolamine, the catalyst is potassium dihydrogen phosphate, and the activator is OP emulsifier.

[0020] The beneficial effects of the present invention are:

[0021] The present invention uses an organic alkaline solution to wet and clean the surface of the FPC, which can improve the surface activity of the product and make its surface have good adhesion, replacing the box-type plasma treatment method commonly used in the prior art. Compared with the box-type plasma treatment method, it can greatly control the cost without reducing the surface performance of the FPC. Through verification, the FPC treated by the two methods was tested, and there was no obvious difference in its surface energy, humorous adhesion, gold surface weldability and aging test performance. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The present invention will be further described below in conjunction with the embodiments.

[0024] Example 1

[0025] The present invention provides a FPC surface treatment process, comprising the following steps:

[0026] S1, preparing a surface treatment liquid, conveying the surface treatment liquid into a treatment tank, and heating the treatment liquid in the treatment tank to 40° C. and maintaining a constant temperature;

[0027] S2, immersing the FPC to be treated into a treatment tank containing a surface treatment liquid, and keeping the FPC in the surface treatment liquid for 30 seconds;

[0028] S3, drying the FPC after the treatment in step "S2" and transferring it into an atmospheric pressure plasma cleaning machine for surface atmospheric plasma treatment, and setting the temperature of the drying machine to 40°C.

[0029] Wherein, the surface treatment liquid is an organic alkaline solution, and its pH value is 9.5.

[0030] Preferably, the surface treatment liquid comprises a saponifier, a catalyst and an activator, the saponifier is triethanolamine, the catalyst is potassium dihydrogen phosphate, and the activator is OP emulsifier.

[0031] Example 2

[0032] The present invention provides a FPC surface treatment process, comprising the following steps:

[0033] S1, preparing a surface treatment liquid, conveying the surface treatment liquid into a treatment tank, and heating the treatment liquid in the treatment tank to 50° C. and maintaining a constant temperature;

[0034] S2, immersing the FPC to be treated into a treatment tank containing a surface treatment liquid, and keeping the FPC in the surface treatment liquid for 40 seconds;

[0035] S3, drying the FPC after the treatment in step "S2" and transferring it into an atmospheric pressure plasma cleaning machine for surface atmospheric plasma treatment, and setting the temperature of the drying machine to 50°C.

[0036] Wherein, the surface treatment liquid is an organic alkaline solution, and its pH is 10.

[0037] Preferably, the surface treatment liquid comprises a saponifier, a catalyst and an activator, the saponifier is triethanolamine, the catalyst is potassium dihydrogen phosphate, and the activator is OP emulsifier.

[0038] Example 3

[0039] The invention provides a FPC surface treatment process, comprising the following steps:

[0040] S1, preparing a surface treatment liquid, conveying the surface treatment liquid into a treatment tank, and heating the treatment liquid in the treatment tank to 55° C. and maintaining a constant temperature;

[0041] S2, immersing the FPC to be treated into a treatment tank containing a surface treatment liquid, and keeping the FPC in the surface treatment liquid for 50 seconds;

[0042] S3, drying the FPC after the treatment in step "S2" and transferring it into an atmospheric pressure plasma cleaning machine for surface atmospheric plasma treatment, and setting the temperature of the drying machine to 55°C.

[0043] Wherein, the surface treatment liquid is an organic alkaline solution, and its pH value is 10.5.

[0044] Preferably, the surface treatment liquid comprises a saponifier, a catalyst and an activator, the saponifier is triethanolamine, the catalyst is potassium dihydrogen phosphate, and the activator is an OP emulsifier.

[0045] In the above three embodiments, the surface of the FPC is treated by infiltration and cleaning with an organic alkaline solution, which can improve the surface activity of the product and make the surface have better adhesion. Then, the atmospheric plasma is treated by atmospheric plasma to form a plasma film on the surface of the FPC. Compared with the direct use of the atmospheric plasma treatment method, the FPC has better high temperature resistance, and the FPC still has good performance after welding. Compared with the box-type plasma treatment method, the method of treating the surface of the FPC in this application is lower in cost, and the surface performance of the FPC can be equal to that of the two treatment methods.

[0046] Example 4

[0047] The present invention provides a FPC surface treatment process, comprising the following steps:

[0048] S1. Prepare the surface treatment liquid, and transport the surface treatment liquid heated to 49.5°C into the treatment tank;

[0049] S2, immersing the FPC to be treated into a treatment tank containing a surface treatment liquid, and keeping the FPC in the surface treatment liquid for 30 seconds;

[0050] S3, drying the FPC after being processed in step "S2" at a temperature of 40°C, and then transplanting it into an atmospheric pressure plasma cleaning machine to perform atmospheric plasma treatment on the surface;

[0051] Wherein, the surface treatment liquid is an organic alkaline solution, and its pH value is 9.5.

[0052] In an embodiment, the processing tank includes a liquid inlet, a liquid outlet, a first opening and a second opening. The first opening and the second opening are arranged on the tank wall of the processing tank, and the two are on the same horizontal line. A horizontal conveying line is arranged to pass through the first opening and exit from the second opening. The horizontal conveying line is used to carry the FPC to be processed into and out of the liquid to be processed.

[0053] Preferably, the surface treatment liquid is input from the liquid inlet and discharged from the liquid outlet, the first opening and the second opening. To maintain relative balance, the input amount of the surface treatment liquid is equal to the output amount of the liquid outlet, the first opening and the second opening.

[0054] It should be noted that in order to achieve the purpose of FPC surface treatment, it is necessary to ensure that the surface treatment liquid always covers the upper surface of the FPC located on the horizontal conveyor line body. Therefore, in order to meet the above conditions, at the beginning, the input amount of the surface treatment liquid is much larger than the output amount, until the treatment liquid in the treatment tank can cover the FPC. At this time, the injection flow rate is changed to make the two the same.

[0055] As an example, the discharged surface treatment liquid will be recycled and its concentration and pH value will be tested. If it meets the conditions, it will be directly heated and used. If it is different from the required conditions, it will be adjusted and then heated for use.

[0056] In the embodiment, the line speed of the horizontal conveyor line is set to 0.45 M / min, and the corresponding length of the processing tank is 2 / 3 meters.

[0057] In an embodiment, the surface treatment liquid includes a saponifier, a catalyst and an activator. As an example, the saponifier is triethanolamine, the catalyst is potassium dihydrogen phosphate, and the activator is OP emulsifier.

[0058] Example 5

[0059] The present invention provides a FPC surface treatment process, comprising the following steps:

[0060] S1. Prepare the surface treatment liquid, and transport the surface treatment liquid heated to 52°C into the treatment tank;

[0061] S2, immersing the FPC to be treated into a treatment tank containing a surface treatment liquid, and keeping the FPC in the surface treatment liquid for 40 seconds;

[0062] S3, drying the FPC after being processed in step "S2" at a temperature of 48°C, and then transplanting it into an atmospheric pressure plasma cleaning machine to perform atmospheric plasma treatment on the surface;

[0063] Wherein, the surface treatment liquid is an organic alkaline solution, and its pH is 10.

[0064] In an embodiment, the processing tank includes a liquid inlet, a liquid outlet, a first opening and a second opening. The first opening and the second opening are arranged on the tank wall of the processing tank, and the two are on the same horizontal line. A horizontal conveying line is arranged to pass through the first opening and exit from the second opening. The horizontal conveying line is used to carry the FPC to be processed into and out of the liquid to be processed.

[0065] Preferably, the surface treatment liquid is input from the liquid inlet and discharged from the liquid outlet, the first opening and the second opening. To maintain relative balance, the input amount and output amount of the surface treatment liquid are equal.

[0066] It should be noted that in order to achieve the purpose of FPC surface treatment, it is necessary to ensure that the surface treatment liquid always covers the upper surface of the FPC located on the horizontal conveyor line body. Therefore, in order to meet the above conditions, at the beginning, the input amount of the surface treatment liquid is much larger than the output amount, until the treatment liquid in the treatment tank can cover the FPC. At this time, the injection flow rate is changed to make the two the same.

[0067] As an example, the discharged surface treatment liquid will be recycled and its concentration and pH value will be tested. If it meets the conditions, it will be directly heated and used. If it is different from the required conditions, it will be adjusted and then heated for use.

[0068] In an embodiment, the line speed of the horizontal conveyor line is set to 0.5 M / min, and the corresponding length of the processing tank is 1 / 3 meter.

[0069] In an embodiment, the surface treatment liquid includes a saponifier, a catalyst and an activator. As an example, the saponifier is triethanolamine, the catalyst is potassium dihydrogen phosphate, and the activator is OP emulsifier.

[0070] Example 6

[0071] The present invention provides a FPC surface treatment process, comprising the following steps:

[0072] S1. Prepare the surface treatment liquid, and transport the surface treatment liquid heated to 55.5°C into the treatment tank;

[0073] S2, immersing the FPC to be treated into a treatment tank containing a surface treatment liquid, and keeping the FPC in the surface treatment liquid for 50 seconds;

[0074] S3, drying the FPC after the treatment in step "S2" at a temperature of 55°C, and then transplanting it into an atmospheric pressure plasma cleaning machine to perform atmospheric plasma treatment on the surface;

[0075] Wherein, the surface treatment liquid is an organic alkaline solution, and its pH value is 10.5.

[0076] In an embodiment, the processing tank includes a liquid inlet, a liquid outlet, a first opening and a second opening. The first opening and the second opening are arranged on the tank wall of the processing tank, and the two are on the same horizontal line. A horizontal conveying line is arranged to pass through the first opening and exit from the second opening. The horizontal conveying line is used to carry the FPC to be processed into and out of the liquid to be processed.

[0077] Preferably, the surface treatment liquid is input from the liquid inlet and discharged from the liquid outlet, the first opening and the second opening. To maintain relative balance, the input amount of the surface treatment liquid is equal to the output amount of the liquid outlet, the first opening and the second opening.

[0078] It should be noted that in order to achieve the purpose of FPC surface treatment, it is necessary to ensure that the surface treatment liquid always covers the upper surface of the FPC located on the horizontal conveyor line body. Therefore, in order to meet the above conditions, at the beginning, the input amount of the surface treatment liquid is much larger than the output amount, until the treatment liquid in the treatment tank can cover the FPC. At this time, the injection flow rate is changed to make the two the same.

[0079] As an example, the discharged surface treatment liquid will be recycled and its concentration and pH value will be tested. If it meets the conditions, it will be directly heated and used. If it is different from the required conditions, it will be adjusted and then heated for use.

[0080] In the embodiment, the line speed of the horizontal conveyor line is set to 0.55 M / min, and the corresponding length of the processing tank is 11 / 24 meters.

[0081] In an embodiment, the surface treatment liquid includes a saponifier, a catalyst and an activator. As an example, the saponifier is triethanolamine, the catalyst is potassium dihydrogen phosphate, and the activator is OP emulsifier.

[0082] The above three embodiments all use an organic alkaline solution to carry out an infiltration cleaning treatment on the surface of the FPC, which can improve the surface activity of the product and make its surface have better adhesion. Then, the atmospheric plasma treatment is carried out by an atmospheric plasma method, so that a plasma film is formed on the surface of the FPC. Compared with the direct use of the atmospheric plasma treatment method, it has better high temperature resistance, and the FPC still has good performance after welding; compared with the box-type plasma treatment method, the method of treating the FPC surface in the present application has lower cost, and the surface performance of the FPC can be equal to that of the two treatment methods.

[0083] Compared with Examples 1-3, a horizontal conveyor line is added to carry FPC, and a corresponding processing tank is set up, so that FPC can be continuously and uninterruptedly fed, products can be produced continuously, the operation is simple, and the timeliness is excellent.

[0084] Comparative test

[0085] Materials preparation:

[0086] (1) After the following operation process: screen printing → assembly → assembly → box-type plasma treatment → molding, 6 FPC products were obtained, numbered A1;

[0087] (2) After the following operation flow: screen printing → assembly → assembly → (using Example 2 and Example 5 disclosed in the present invention to process FPC in sequence) → molding, two groups of FPC products are obtained, numbered B1 and B2, respectively, and each group of FPC products has 6 pieces;

[0088] (3) After the following processing flow: silk screen printing → assembly → assembly → molding, 6 FPC products are obtained, numbered C1.

[0089] Comparative Example 1 (dyne value detection)

[0090]

[0091]

[0092] Comparative Example 2 (CVL color difference)

[0093]

[0094]

[0095] Comparative Example 3 (Ink Adhesion Test)

[0096]

[0097] Comparative Example 4 (Gold Surface Weldability Test)

[0098]

[0099]

[0100] Comparative Example 5 (Aging Test)

[0101]

[0102]

[0103] It can be seen from the above table that the flexible circuit board obtained by the FPC processing process of the present invention can achieve the same level of performance in all aspects as that of the box-type plasma processing process.

[0104] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0105] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A FPC surface treatment process, characterized in that: The steps include: S1, preparing a surface treatment liquid, and conveying the surface treatment liquid into a treatment tank; S2, immersing the FPC to be treated into a treatment tank containing a surface treatment liquid, and keeping the FPC in the surface treatment liquid for 30-50 seconds; S3, drying the FPC after being processed in step "S2" and transferring it into an atmospheric pressure plasma cleaning machine for surface atmospheric plasma treatment; Wherein, the surface treatment liquid is an organic alkaline solution with a pH of 9.5-10.5, and the temperature of the treatment liquid in the treatment tank is controlled to be 49-55°C.

2. The FPC surface treatment process according to claim 1, characterized in that: The drying temperature of the FPC in step S3 is 40-55°C.

3. The FPC surface treatment process according to claim 1, characterized in that: The surface treatment liquid is heated in the treatment tank.

4. The FPC surface treatment process according to claim 1, characterized in that: The surface treatment liquid is heated and then transported to the treatment tank. At this time, the temperature of the surface treatment liquid needs to be heated to 49.5-55.5°C.

5. The FPC surface treatment process according to claim 1, characterized in that: The processing tank comprises a liquid inlet, a liquid outlet, a first opening and a second opening, wherein the first opening and the second opening are arranged on the tank wall of the processing tank, and the first opening and the second opening are on the same horizontal line, wherein the surface treatment liquid is input from the liquid inlet and discharged from the liquid outlet, the first opening and the second opening, and the input amount of the surface treatment liquid is equal to the output amount of the liquid outlet, the first opening and the second opening.

6. The FPC surface treatment process according to claim 5, characterized in that: The FPC is transported through a horizontal conveyor line, and the horizontal conveyor line enters from the first opening and is output from the second opening.

7. The FPC surface treatment process according to claim 6, characterized in that: The surface treatment liquid needs to cover the upper surface of the FPC located on the horizontal conveyor line body.

8. The FPC surface treatment process according to claim 1, characterized in that: The line speed of the horizontal conveyor line is set to 0.45-0.55 M / min.

9. The FPC surface treatment process according to any one of claims 1 to 5, characterized in that: The surface treatment liquid comprises a saponifier, a catalyst and an activator.

10. The FPC surface treatment process according to claim 8, characterized in that: The saponifier is triethanolamine, the catalyst is potassium dihydrogen phosphate, and the activator is OP emulsifier.

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