Conductive polymer patterning hollow transfer printing method

Abstract

The invention provides a conductive polymer patterning hollowed-out transfer printing method, which comprises the following steps of: preparing a template with a hollowed-out pattern, pasting the template on a substrate, coating a conductive polymer material on a hollowed-out pattern area, and carrying out graded curing on the coated conductive polymer material, namely, carrying out preliminary curing before stripping the template, and completely curing after stripping the template, and finally transferring the cured conductive polymer pattern to a target substrate through a transfer film. According to the conductive polymer patterning printing method, the patterning problem of polymer materials with different viscosities is effectively solved in the mode that the hollowed-out template is combined with the blade coating process, accurate patterning treatment can be achieved for low-viscosity or high-viscosity conductive polymers, and the conductive polymer patterning printing method has wide applicability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of conductive polymer material printing, and particularly relates to a conductive polymer patterning hollow transfer printing method. BACKGROUND

[0002] Traditional conductive polymer patterning technologies mainly include screen printing, inkjet printing, and photolithography technology. However, many new conductive polymer materials often exhibit low or high viscosity characteristics due to their unique molecular structure and physical properties, which makes it difficult for traditional screen printing processes to be applicable. Low-viscosity conductive polymers are prone to capillary penetration and edge diffusion during screen printing, resulting in blurred pattern edges and increased line width deviation. High-viscosity materials have problems such as insufficient shear thinning, mesh blockage, and uneven printing, which seriously affect the pattern quality and production efficiency.

[0003] Although inkjet printing technology has high precision, it is expensive and has very strict requirements for the rheological properties of the ink. Although photolithography technology has the highest precision, it is complex and requires expensive photolithography equipment and strict environmental control, which is not suitable for large-scale industrial production.

[0004] In the prior art, some researchers have proposed stencil printing technology, but most of the schemes have the following problems: first, the stencil preparation precision is limited, and it is difficult to achieve micron-level precision; second, the stress control during polymer curing is insufficient, which easily leads to pattern deformation; third, the transfer process is imperfect, and the transfer efficiency is low and the pattern is easily damaged.

[0005] In addition, the cross-linking and curing characteristics of conductive polymer materials also pose special requirements on the patterning process. The material may shrink in volume and release stress during curing, which affects the pattern precision and integrity. The existing process lacks effective stress control and pattern protection mechanisms. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides a conductive polymer patterning hollow transfer printing method to solve the technical problems of low precision, narrow material range, and high process complexity in the prior art, and to realize high-precision patterning of polymer materials with a wide viscosity range.

[0007] The present application achieves the above technical objectives through the following technical means.

[0008] A conductive polymer patterning hollow transfer printing method, comprising the following steps:

[0009] Template preparation: preparing a template with a hollow pattern;

[0010] Template application: applying the template to the substrate;

[0011] Polymer coating: coating conductive polymer material on the area of the hollowed-out pattern;

[0012] Hierarchical curing: hierarchical curing of the coated conductive polymer material, including preliminary curing before peeling off the template and complete curing after peeling off the template;

[0013] Pattern transfer: transferring the cured conductive polymer pattern to the target substrate through a transfer film.

[0014] Further, the substrate is a glass substrate or kraft paper board, and the surface roughness requirement is ≤5 μm.

[0015] Further, the template is a polyvinyl chloride substrate, and the hollowed-out pattern is made by laser engraving.

[0016] Further, before the template is applied, a transfer film is pasted on the surface of the hollowed-out pattern as protection; after the template is applied, the transfer film is peeled off.

[0017] Further, in the polymer coating step:

[0018] For viscosity ≤1000 cP, the doctor blade speed is 1-3 cm / s, the doctor blade pressure is 0.2-0.5 MPa, and the doctor blade angle is 60-75°;

[0019] For viscosity of 1000-5000 cP, the doctor blade speed is 2-5 cm / s, the doctor blade pressure is 0.4-0.8 MPa, and the doctor blade angle is 45-60°;

[0020] For viscosity ≥5000 cP, the doctor blade speed is 0.5-2 cm / s, the doctor blade pressure is 0.6-0.8 MPa, and the doctor blade angle is 30-45°.

[0021] Further, in the hierarchical curing step:

[0022] The preliminary curing temperature is 25-40℃, the curing time is 5-25 min, the curing degree is 30-50%, and the relative humidity of the curing environment is 45-65%;

[0023] After preliminary curing, the template is peeled off at an angle of 30-45° and a speed of 2-8 mm / s; when a sudden change in peeling force occurs during peeling, the peeling is paused and stress release treatment is performed;

[0024] After the template is peeled off, the patterned polymer remaining on the substrate is subjected to complete curing treatment, and the final crosslinking degree requirement is ≥95%.

[0025] Further, the curing method is any of the following:

[0026] Thermal curing, temperature 60-150℃, time 15-300 min;

[0027] UV light curing, wavelength 365nm, time 1-10min;

[0028] Chemical crosslinking curing.

[0029] Further, the template pasting process adopts pressure pasting, the pasting pressure is 0.2-0.8MPa, the pasting duration is 30-60s, and exhaust treatment is carried out after pasting.

[0030] Further, in the pattern transfer step, a flexible transfer film is adopted, and pressure assistance is adopted in the transfer process, the transfer pressure is 0.2-0.5MPa, the transfer temperature is 25℃, and the transfer time is 30-180min.

[0031] Further, the laser engraving adopts a CO2 laser, the laser power is 20-35W, the scanning speed is 400-800mm / min, and the pulse frequency is 15-25kHz.

[0032] The present application has the following beneficial effects:

[0033] (1) The present application provides a conductive polymer patterned hollow transfer printing method, which effectively solves the patterning problem of different viscosity polymer materials by means of hollow template combined with the way of blade coating process, whether it is low viscosity or high viscosity conductive polymer, accurate patterning process can be realized, and it has wide applicability.

[0034] (2) The present application adopts high-precision laser engraving technology to prepare a hollow template, combines precise coating and hierarchical curing process, realizes pattern line width accuracy ±10μm, and edge sharpness ≥90%, which meets the technical requirements of precision electronic devices.

[0035] (3) The present application effectively controls the stress distribution and release in the polymer curing process through hierarchical curing and peeling process, greatly reduces the pattern deformation and cracking phenomenon, and improves the yield.

[0036] (4) The whole process of the present application does not need complex equipment investment and strict environmental control, and the operation is simple and easy to industrialization. Compared with the traditional photolithography process, the production cost and technical threshold are greatly reduced. And there is no need to use organic solvents and toxic chemicals in the process, and the transfer film used can be reused, which meets the green manufacturing requirements. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 It is a pasting diagram of template and substrate in the present application;

[0038] Figure 2 It is a template and substrate state diagram when coating;

[0039] Figure 3 For Figure 1 and Figure 2 the positive projection of the hollowed-out pattern on the template;

[0040] Figure 4 For Figure 1 the actual test sample picture corresponding to the schematic diagram.

[0041] Reference signs:

[0042] 1 - template; 2 - substrate; 3 - hollowed-out pattern; 4 - first transfer film. DETAILED DESCRIPTION

[0043] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0044] The conductive polymer patterned hollow transfer printing method of the present application comprises the following steps:

[0045] Step 1, substrate pretreatment

[0046] As shown in Figures 1 to 4 , a flat plate is selected as the substrate 2, such as a glass substrate, kraft paper board, etc. The surface of the substrate 2 is cleaned to remove dirt such as oil and dust. The surface roughness of the substrate 2 is required to be ≤5 μm. For the substrate 2 of hydrophilic material, hydrophobic treatment can also be performed to facilitate subsequent template peeling.

[0047] Step 2, template preparation

[0048] A polyvinyl chloride base material is selected to make the template 1, and the required printing pattern is made on the surface of the template 1 by laser engraving. The engraving depth completely penetrates the template 1, forming a hollow pattern 3 structure.

[0049] After the pattern engraving is completed, the first transfer film 4 is pasted on the surface of the hollow pattern 3 (the side not in contact with the substrate 2) to protect the hollow pattern 3 structure and prevent the hollow pattern 3 from deforming. The first transfer film 4 can specifically use a polyester transfer film.

[0050] Step 3, template pasting

[0051] The template 1 with the prepared hollow pattern 3 is pasted on the surface of the substrate 2. The pasting process uses pressure bonding, and the pasting pressure is controlled at 0.2-0.8 MPa, and the pasting time is 30-60 s. After pasting, air removal treatment is performed to remove the air bubbles between the template 1 and the substrate 2, and to ensure that the two are tightly bonded. After the template 1 is pasted, the first transfer film 4 is peeled off.

[0052] Step 4, polymer coating

[0053] The conductive polymer material is coated on the hollow pattern 3 area of the template 1. According to the rheological properties of the conductive polymer material, different coating parameters are adopted:

[0054] For low viscosity materials (≤1000 cP), the coating speed is 1-3 cm / s, the coating pressure is 0.2-0.5 MPa, and the coating angle is 60-75°;

[0055] For medium viscosity materials (1000-5000 cP), the coating speed is 2-5 cm / s, the coating pressure is 0.4-0.8 MPa, and the coating angle is 45-60°;

[0056] For high viscosity materials (≥5000 cP), the coating speed is 0.5-2 cm / s, the coating pressure is 0.6-0.8 MPa, and the coating angle is 30-45°;

[0057] The filling quality is monitored in real time during the coating process.

[0058] Step 5, preliminary curing

[0059] A staged curing process with temperature gradient control is adopted, in which preliminary curing is carried out in this step, the preliminary curing temperature is 25-40℃, the curing time is 5-25 min, the curing degree is controlled at 30-50%, and the relative humidity of the curing environment is controlled at 45-65%; the curing degree is monitored in real time during the preliminary curing process, and the process is stopped when the required curing degree is reached.

[0060] Step 6, template peeling

[0061] After the conductive polymer material reaches the set preliminary curing degree, the template 1 is peeled off from the substrate 2. The peeling angle is controlled at 30-45°, and the peeling speed is 2-8 mm / s. The peeling force change is continuously monitored during the peeling process, and the peeling is paused when the peeling force changes suddenly, and stress release treatment is carried out to avoid pattern damage.

[0062] Step 7, complete crosslinking

[0063] After the template 1 is peeled off, the patterned polymer left on the substrate 2 is subjected to complete curing treatment. According to the characteristics of the conductive polymer material, specific curing methods can be selected, including thermal curing (60-150℃, 15-300 min), ultraviolet light curing (365 nm, 1-10 min), and chemical crosslinking curing. The final crosslinking degree is required to be ≥95%, to ensure the mechanical strength and electrical stability of the pattern.

[0064] Step 8, pattern transfer

[0065] The second transfer film is used to transfer the cured polymer pattern to the target substrate. The second transfer film is a flexible transfer film. The transfer process is assisted by pressure, with a transfer pressure of 0.2-0.5 MPa, a transfer temperature of 25°C, and a transfer time of 30-180 min. After the transfer is complete, the second transfer film is peeled off, and the final patterned product is obtained on the desired target substrate.

[0066] Example 1, printing of a low-viscosity conductive polymer

[0067] For an aqueous conductive polyaniline solution with a viscosity of 500 cP, the patterned product is prepared as follows:

[0068] Step 1: A soda-lime glass substrate with a thickness of 1.0 mm is selected as the base. The base is cleaned with ethanol and deionized water, respectively, to remove dirt on the surface of the base. The surface roughness is measured to be 1.15 μm using a contact profilometer, which meets the process requirements.

[0069] Step 2: A polyvinyl chloride substrate with a thickness of 0.8 mm is used to prepare a conductive line pattern with a line width of 50 μm using a CO2 laser engraving machine. The laser parameters are set as follows: power 25 W, scanning speed 600 mm / min, and pulse frequency 20 kHz. After engraving, a polyester transfer film with a thickness of 0.5 mm is attached to the pattern surface.

[0070] Step 3: The hollowed-out template is attached flat to the surface of the glass substrate, with an attachment pressure of 0.5 MPa and an attachment time of 45 s. A vacuum pump is used to exhaust for 30 s to ensure that no air bubbles remain. After the attachment is complete, the polyester transfer film is peeled off.

[0071] Step 4: The hollowed-out pattern area of the template is coated. Since the viscosity of the coated conductive polymer material is low, a slow and precise coating is used. The coating speed is set to 2 cm / s, the coating pressure is 0.3 MPa, and the coating angle is 70°. The ambient temperature is maintained at 25°C and the relative humidity is 55% during the coating process.

[0072] Step 5: The coated sample is placed in a constant-temperature oven for preliminary curing, with a temperature setting of 35°C and a curing time of 15 min.

[0073] Step 6: The template is slowly peeled off at an angle of 35° in the semi-cured state, with a peeling speed controlled at 5 mm / s.

[0074] Step 7: The sample after the template is peeled off (polymer pattern) is further cured at 80°C for 60 min.

[0075] Step 8: A flexible polyurethane transfer film is used for transfer at a pressure of 1.5 MPa, with a transfer temperature of 40°C and a transfer time of 30 s. After the transfer is complete, a high-precision patterned conductive polymer film pattern is obtained.

[0076] Example 2, printing of high viscosity conductive polymer

[0077] A pattern was prepared for the epoxy-based conductive silver paste with a viscosity of 8000 cP:

[0078] Based on Example 1, the process parameters were adjusted as follows: the doctor blade speed was 1 cm / s, the doctor blade pressure was 0.8 MPa, and the doctor blade angle was 40°. The preliminary curing temperature was increased to 40 °C, and the curing time was extended to 20 min. A high viscosity conductive polymer film pattern was finally obtained.

[0079] Example 3, printing for a flexible substrate as the target substrate

[0080] A smooth kraft paper film was selected as the target substrate, and the conductive polymer was a medium viscosity polyurethane mixture doped with conductive carbon black (viscosity of about 3000 cP).

[0081] Based on Example 1, the process parameters were adjusted as follows: the doctor blade speed was 3 cm / s, the doctor blade pressure was 0.6 MPa, and the doctor blade angle was 55°. Thermal curing was used, with a preliminary curing temperature of 35 °C and a curing time of 12 min. The pattern transfer used a gradual pressure release technique to avoid deformation of the flexible substrate.

[0082] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0083] The present application is not limited to the above-described embodiments, and any obvious improvements, replacements, or modifications made by those skilled in the art without departing from the essential content of the present application are within the scope of the present application.

Claims

1. A conductive polymer patterned hollow transfer printing method, characterized by: The steps include: Template preparation: preparing a template with a hollow pattern; Template application: Apply the template to the substrate; Polymer coating: coating the conductive polymer material on the hollow pattern area; Gradual curing: The coated conductive polymer material is cured in stages, which includes preliminary curing before stripping the template and complete curing after stripping the template. Pattern transfer: The cured conductive polymer pattern is transferred to the target substrate via a transfer film.

2. The conductive polymer patterned hollow transfer printing method according to claim 1, characterized in that: The substrate is a glass substrate or kraft paperboard, and the surface roughness is required to be ≤5μm.

3. The conductive polymer patterned hollow transfer printing method according to claim 1, characterized in that: The template is made of polyvinyl chloride, and the hollow pattern is made by laser engraving.

4. The conductive polymer patterned hollow transfer printing method according to claim 1, wherein: Before the template is applied, a transfer film is pasted on the upper surface of the hollow pattern for protection; after the template is applied, the transfer film is peeled off.

5. The conductive polymer patterned hollow transfer printing method according to claim 1, wherein: During the polymer coating step: For viscosity ≤1000cP, the scraping speed is 1-3cm / s, the scraping pressure is 0.2-0.5MPa, and the scraping angle is 60-75°; For viscosity of 1000-5000 cP, the scraping speed is 2-5 cm / s, the scraping pressure is 0.4-0.8 MPa, and the scraping angle is 45-60°; For viscosity ≥5000 cP, the scraping speed is 0.5-2 cm / s, the scraping pressure is 0.6-0.8 MPa, and the scraping angle is 30-45°.

6. The conductive polymer patterned hollow transfer printing method according to claim 1, characterized in that: During graded curing: The initial curing temperature is 25-40°C, the curing time is 5-25 minutes, the curing degree is 30-50%, and the relative humidity of the curing environment is 45-65%. After initial curing, peel off the template at a peeling angle of 30-45° and a peeling speed of 2-8 mm / s; When a sudden change in peeling force occurs during the peeling process, the peeling is suspended and stress release is performed; After the template is peeled off, the patterned polymer remaining on the substrate is fully cured, and the final cross-linking degree is required to be ≥95%.

7. The conductive polymer patterned hollow transfer printing method according to claim 6, characterized in that: The curing method is any of the following: Thermal curing, temperature 60-150°C, time 15-300 minutes; UV curing, wavelength 365nm, time 1 to 10 minutes; Chemical cross-linking curing.

8. The conductive polymer patterned hollow transfer printing method according to claim 1, characterized in that: The template is laminated using pressure, with a laminating pressure of 0.2 to 0.8 MPa and a laminating time of 30 to 60 seconds. Exhaust treatment is performed after laminating.

9. The conductive polymer patterned hollow transfer printing method according to claim 1, characterized in that: In the pattern transfer step, a flexible transfer film is used, and the transfer process is pressure-assisted, with a transfer pressure of 0.2 to 0.5 MPa, a transfer temperature of 25° C., and a transfer time of 30 to 180 min.

10. The conductive polymer patterned hollow transfer printing method according to claim 3, characterized in that: Laser engraving uses a CO2 laser with a laser power of 20 to 35W, a scanning speed of 400 to 800 mm / min, and a pulse frequency of 15 to 25 kHz.

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