Process for improving burrs of PTFE (Polytetrafluoroethylene) gong plate and application of process

Abstract

The invention discloses a process for improving PTFE (polytetrafluoroethylene) routing board burrs and application thereof.The process for improving the PTFE routing board burrs comprises the following steps that S1, the upper surface and the lower surface of a PTFE board are each coated with a removable coating, S2, the PTFE board is subjected to coating curing, S3, the PTFE board is subjected to routing treatment, and S4, after routing, the PTFE board is placed in water at the temperature of 20-100 DEG C to remove the coatings, and the condition that the PTFE board generates burrs is observed, the washing-fading coating takes water-soluble resin as a main body, and further comprises an adhesion promoter. According to the process for improving the burrs of the PTFE routing board, the number of the burrs after the PTFE board is subjected to routing can be small, the binding force between the coating coated on the board and the PTFE board is high, meanwhile, the coating can be easily removed through tap water after the board is subjected to routing, the performance of the PTFE board cannot be affected, and the process further has the advantages of being simple and easy to operate and can be widely applied.

Description

Technical Field

[0001] The invention relates to the field of printed circuit board gong plate processing, and in particular to a process for improving burrs of PTFE gong plates and an application thereof. Background Art

[0002] PCB high-frequency board PTFE is a polymer material with special properties and has broad application prospects in the field of high-frequency circuits. Due to its excellent electrical properties and low dielectric loss, PTFE can be used to manufacture high-frequency circuit boards, especially in the fields of wireless communication and radar. PTFE materials can provide lower signal attenuation and higher signal transmission speed, making high-frequency circuits have better performance and stability. With the rapid development of high-frequency communication and radar technology, the requirements for PCB high-frequency boards are getting higher and higher. In the preparation process of PTFE high-frequency boards, the gong cutting step is a crucial process that affects the quality of high-frequency circuit boards. In the prior art, when the PTFE sheet is formed, the gong knife directly contacts the PCB substrate during the cutting process. The PTFE sheet has good toughness and is not easy to cut. A large amount of hair and burrs will be generated in the notch. The use of ordinary gong knives to mill the high-frequency board will make the burrs very many and uneven. At present, manual repair, special auxiliary materials (special milling cutters, kraft paper, etc.) or reducing the milling board cutting speed are mainly used to reduce burrs, but this will lead to problems such as poor repair, rising costs and low efficiency. In addition, the current gong knife type has insufficient cutting capacity and is prone to entanglement. The knife is very easy to break when cutting the corner of PTFE high-frequency plate, and high-frequency knife is expensive, and knife breakage leads to increased costs; the swarf entangled with the knife needs to be cleaned in time, but the limited space during processing makes it difficult to remove the chips. Continuing to use the knife with chips is very likely to lead to quality problems such as inaccurate size or swarf deviation. Stopping the machine to clean the chips will also affect production efficiency and require cleaning fees, increasing production costs.

[0003] The current solutions to the burrs on PTFE gong plates in the industry include: 1. Using a double-edged high-frequency gong cutter to gong the PTFE high-frequency board. By changing the shape of the gong cutter, the chip entanglement is improved, but burrs still exist, and the cost of double-edged high-frequency gong cutters is relatively high; 2. Tinning or printing solder mask ink on the surface of PTFE. The solder mask ink or tin layer has a protective effect during gong cutting and can reduce the generation of burrs on the gong plate. However, the ink cannot be removed after welding, and the tin layer needs to be removed with chemicals. The chemicals can easily corrode the board, causing performance degradation and the operation process is more complicated. Summary of the invention

[0004] In view of the defects in the prior art, the present invention proposes a process for improving the burrs of PTFE gong plates and its application.

[0005] The present invention provides a process for improving burrs of a PTFE gong plate, comprising the following steps:

[0006] S1. Coat a washable coating on both the upper and lower surfaces of the PTFE plate;

[0007] S2. Curing the coating on the PTFE plate;

[0008] S3. Perform gong plate treatment on the PTFE plate;

[0009] S4. After rubbing, place the PTFE plate in 20-100℃ water to remove the coating and observe the burrs on the PTFE plate;

[0010] The washable coating is mainly composed of a water-soluble resin and also includes an adhesion promoter; the water-soluble resin has excellent film properties, can form a tough and durable coating, and has strong adhesion, which can ensure a firm bond between the coating and the substrate.

[0011] In the process of improving the burrs of the PTFE gong plate of the present invention, a layer of washable coating is coated on the surface of the PTFE plate. The washable coating is applied to the surface of the PTFE plate before gonging by utilizing the strong bonding force, high hardness and easy washability of the washable coating, and is cured. The cured washable coating increases the strength of the PTFE plate and improves the chip removal ability of the gong plate. During gonging, the PTFE sample has high strength, which makes up for the defect that burrs are easily generated during cutting due to its soft characteristics. The high strength makes the PTFE plate easy to cut, which significantly improves the effect of suppressing the burrs of the gong plate. After gonging, the coating can be washed off with tap water, which does not pollute or corrode the plate.

[0012] Furthermore, the washable coating comprises the following components: water-soluble resin, solvent, defoamer, dispersant, leveling agent, adhesion promoter. In parts by weight, the specific components are as follows: 20-90 parts of water-soluble resin, 5-50 parts of solvent, 0.01-1 part of defoamer, 0.01-1 part of dispersant, 0.01-1 part of leveling agent, 0.01-10 parts of adhesion promoter;

[0013] It may also include 0-50 parts of filler, 0-5 parts of thixotropic agent and 0-20 parts of starch.

[0014] The water-soluble resin is a mixture of one or more of water-based epoxy or modified resins, water-based polyurethane or modified resins, water-based acrylate or modified resins, water-based polyester or modified resins, etc. This type of resin can be dissolved in water after curing, and is preferably a water-soluble modified acrylic resin.

[0015] The solvent is any one or more of water, acetone, ethanol, dibasic lipids, propylene glycol methyl ether or N,N-dimethylformamide.

[0016] The filler is an organic filler or an inorganic filler, including but not limited to calcium carbonate, talc, aluminum hydroxide, silicon dioxide, and glass powder, preferably one or two of talc and silicon dioxide, with an average particle size of 1250-10000 mesh.

[0017] The thixotropic agent includes but is not limited to any one of fumed silica or organic bentonite, preferably fumed silica.

[0018] The defoaming agent can be selected from silicone defoaming agents or polyether defoaming agents.

[0019] The dispersant can be a polymer dispersant or an ionic dispersant.

[0020] The leveling agent can be an acrylic leveling agent, a polyester leveling agent, an organic silicon leveling agent or a fluorocarbon leveling agent.

[0021] The adhesion promoter may be at least one of a silane coupling agent or a modified epoxy copolymer.

[0022] The starch includes but is not limited to any one of sweet potato starch, wheat starch and corn starch.

[0023] The preparation process of the water-soluble coating is as follows: weigh the water-soluble resin, solvent, defoamer, dispersant, leveling agent, and adhesion promoter by weight, use a high-speed disperser (speed 500-2000r / min), stir for 10-60min, then add filler, starch, and thixotropic agent by weight, and continue stirring for 20-120min to obtain a coating composition.

[0024] Furthermore, the hardness of the washable coating after curing is ≥4B; the high hardness of the coating after curing can provide strong supporting force to the PTFE plate and inhibit the generation of burrs during gong operation.

[0025] Furthermore, the bonding strength between the washable coating and the PTFE plate after curing is ≥2B.

[0026] Furthermore, the coating thickness of the washable coating on the PTFE plate is 20-300 μm, preferably 50-150 μm, and more preferably 50-100 μm; the best effect can be achieved when the thickness is 100 μm. If the film thickness is further increased, the coating will be difficult to solidify, reducing production efficiency, and the material cost is high, which will increase costs.

[0027] Furthermore, the washable coating is cured by any one of baking, room temperature, and UV curing, with a curing temperature of 20-150° C. and a curing time of 10-60 min.

[0028] Furthermore, the coating method is any one of brushing, spraying, roller coating and silk screen printing.

[0029] Furthermore, the washable coating has a viscosity of 500-50000 mpa·s.

[0030] The invention also provides application of the process in processing PTFE gong plates.

[0031] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0032] (1) The process for improving the burrs of PTFE gong plates provided by the present invention can improve the strength of the PTFE plates and the chip removal capacity of the gong plates;

[0033] (2) In the process for improving burrs of PTFE gong plates provided by the present invention, the coating has a strong bonding force with the PTFE plate after curing, and can maintain the stability of the gong plate processing process;

[0034] (3) The process for improving the burrs of PTFE gong plates provided by the present invention does not require the use of chemical agents to remove the coating, does not pollute or corrode the plate, and has a simple process and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 This is a schematic diagram of the structure of the PTFE plate obtained in step S2 of the present invention.

[0037] Reference numerals: 1 - washable coating; 2 - PTFE plate. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0039] Example

[0040] The present invention is further described below in conjunction with specific examples and comparative examples. The following specific examples are all preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and are particularly not limited to the types of the various component raw materials used in the following specific examples.

[0041] 1. The sources of raw materials for the embodiments and comparative examples are as follows:

[0042] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present invention are commercially available.

[0043] Coating #1: 60 parts by weight of water-soluble polyurethane resin, 10 parts by weight of propylene glycol methyl ether, 20 parts by weight of 5000 mesh talc, 1 part by weight of fumed silica, 0.5 parts by weight of silicone defoamer, 0.3 parts by weight of polymer dispersant, 0.2 parts by weight of acrylic leveling agent, 2 parts by weight of KH560, 6 parts by weight of corn starch, viscosity 2000 mPa·s;

[0044] Coating #2: 70 parts by weight of water-soluble acrylic resin, 5 parts by weight of propylene glycol methyl ether, 25 parts by weight of 5000 mesh talc, 0.4 parts by weight of silicone defoamer, 0.3 parts by weight of polymer dispersant, 0.2 parts by weight of acrylic leveling agent, 0.1 parts by weight of KH560, viscosity 1000 mPa·s;

[0045] Coating #3: 60 parts by weight of water-soluble acrylic resin, 5 parts by weight of propylene glycol methyl ether, 20 parts by weight of 3000 mesh calcium carbonate, 1 part by weight of fumed silica, 0.5 parts by weight of silicone defoamer, 0.3 parts by weight of polymer dispersant, 0.2 parts by weight of acrylic leveling agent, 2 parts by weight of KH560, 11 parts by weight of corn starch, viscosity 1500 mPa·s;

[0046] Coating #4: 50 parts by weight of water-soluble polyester resin, 10 parts by weight of propylene glycol methyl ether, 25 parts by weight of 5000 mesh talc, 1 part by weight of fumed silica, 0.5 parts by weight of silicone defoamer, 0.3 parts by weight of polymer dispersant, 0.2 parts by weight of acrylic leveling agent, 2 parts by weight of KH560, 11 parts by weight of corn starch, viscosity is 3000 mPa·s.

[0047] 2. Various performance test methods

[0048] (1) Coating hardness test: Test according to the national standard GB 6739-86 "Coating hardness pencil hardness method".

[0049] (2) Coating thickness test: Use instrument (coating thickness gauge) for testing.

[0050] (3) Test of burr count of PTFE plate: Observe the rear section of the gong plate with naked eyes, and the number of burrs per meter should be ≤10.

[0051] (4) Test of adhesion between PTFE plate and coating: Test according to GBT9286-1998 “Scratch test for paint and varnish”.

[0052] Example 1

[0053] Embodiment 1 The process of improving the burr of PTFE gong plate comprises the following steps:

[0054] S1. Select the above coating #1, and apply a coating with a thickness of 20μm, 50μm, 100μm, and 150μm on the upper and lower surfaces of the PTFE plate by roller coating;

[0055] S2. The PTFE plate of step S1 is baked at 100°C for 30 min to cure the coating. After curing, the coating hardness is 2B and the bonding strength with the PTFE plate is 5B;

[0056] S3. The obtained PTFE plate is subjected to gong plate;

[0057] S4. After the gong plate is completed, soak the PTFE plate in 50℃ tap water to remove the coating and observe the burrs generated on the PTFE plate.

[0058] Example 2

[0059] Embodiment 2 The process of improving the burr of PTFE gong plate comprises the following steps:

[0060] S1. Select the above coating #2, and apply a coating with a thickness of 20μm, 50μm, 100μm, and 150μm on the upper and lower surfaces of the PTFE plate by roller coating;

[0061] S2. The PTFE plate of step S1 is baked at 120°C for 30 min to cure the coating. After curing, the hardness of the coating is F and the bonding strength with the PTFE plate is 5B;

[0062] S3. The obtained PTFE plate is subjected to gong plate;

[0063] S4. After the gong plate is completed, soak the PTFE plate in 50℃ tap water to remove the coating and observe the burrs generated on the PTFE plate.

[0064] Example 3

[0065] Embodiment 3 The process of improving the burr of PTFE gong plate comprises the following steps:

[0066] S1. Select the above coating #3, and apply a coating with a thickness of 100 μm on the upper and lower surfaces of the PTFE plate by roller coating;

[0067] S2. The PTFE plate of step S1 is baked at 150°C for 30 min to cure the coating. After curing, the coating hardness is H and the bonding strength with the PTFE plate is 5B;

[0068] S3. The obtained PTFE plate is subjected to gong plate;

[0069] S4. After the gong plate is completed, soak the PTFE plate in 50℃ tap water to remove the coating and observe the burrs generated on the PTFE plate.

[0070] Example 4

[0071] Embodiment 4 The process of improving the burr of PTFE gong plate comprises the following steps:

[0072] S1. Select the above coating #4, and apply a coating having a thickness of 100 μm on the upper and lower surfaces of the PTFE plate by roller coating;

[0073] S2. The PTFE plate of step S1 is baked at 120°C for 30 min to cure the coating. After curing, the hardness of the coating is HB, and the bonding strength with the PTFE plate is 5B;

[0074] S3. The obtained PTFE plate is subjected to gong plate;

[0075] S4. After the gong plate is completed, soak the PTFE plate in 50℃ tap water to remove the coating and observe the burrs generated on the PTFE plate.

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 2 is that no coating is applied on the surface of the PTFE plate.

[0078] Table 1 Effects of Examples and Comparative Examples

[0079]

[0080] The processes for improving the burrs of PTFE gong plates of Examples 1-4 all include the operation of coating a coating on a PTFE plate, and the high strength of the coating and the strong bonding force between the PTFE plate and the coating are utilized, so that the PTFE plate can not only suppress the generation of burrs but also improve the chip removal capacity when processing the gong plate. The number of burrs on the PTFE plate after gong plate is less than 5, and the bonding force between the coating and the PTFE plate is also above 2B, which can better cooperate with each other to improve the product quality during the gong plate processing, and the coating can be washed off by soaking in tap water of a certain temperature, and will not cause damage or pollution to the PTFE plate. Therefore, the process for improving the burrs of PTFE gong plates of the present invention is suitable for large-scale application.

[0081] Comparative Example 1 is compared with Example 2. The coating mainly composed of the water-soluble resin of the present invention is not coated on the PTFE plate before the gong plate is processed, so that the PTFE plate after the gong plate processing has serious burrs, and subsequent burr repair and other work are required, which increases the complexity of the operation and is difficult to directly apply. The above comparative examples cannot suppress the generation of burrs on the PTFE plate during the gong plate processing, which makes the gong plate processing of the PTFE plate more complicated.

[0082] Based on the test data on the hardness of the coating, the bonding strength between the coating and the PTFE plate, and the burrs generated after PTFE plate gong plate processing, the process of improving the burrs of PTFE gong plates using Examples 1-4 has obvious advantages over the control example in the field of PTFE plate gong plate processing, and can effectively meet the high standards of customers and the market.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for improving burrs of PTFE gong plates, characterized in that: The steps include: S1. Coat a washable coating on both the upper and lower surfaces of the PTFE plate; S2. Curing the coating on the PTFE plate; S3. Perform gong plate treatment on the PTFE plate; S4. After rubbing, place the PTFE plate in 20-100℃ water to remove the coating and observe the burrs on the PTFE plate; The washable coating is mainly composed of a water-soluble resin and also includes an adhesion promoter.

2. The process according to claim 1, characterized in that The washable coating has a hardness of ≥4B after curing.

3. The process according to claim 1, characterized in that The bonding strength between the washable coating and the PTFE plate after curing is ≥2B.

4. The process according to claim 1, characterized in that The washable coating has a coating thickness of 20-300 μm on the PTFE plate.

5. The process according to claim 1, characterized in that The water-soluble resin is a mixture of one or more of water-soluble epoxy or modified resins thereof, water-soluble polyurethane or modified resins thereof, water-soluble acrylate or modified resins thereof, and water-soluble unsaturated polyester or modified resins thereof.

6. The process according to claim 1, characterized in that The washable coating is cured by any one of baking, room temperature and UV curing.

7. The process according to claim 1, characterized in that The coating method is any one of brush coating, spray coating, roller coating and silk screen printing.

8. The process according to claim 1, characterized in that The viscosity of the washable coating is 500-50000 mpa·s.

9. Application of the process described in any one of claims 1 to 8 in PTFE plate gong plate processing.

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