CN106750431A - A kind of preparation method of polymer flexible film - Google Patents

Abstract

The present invention relates to a method for preparing a polymer flexible film, and specifically to a coating-ultra-low temperature grinding composite preparation method for a high-precision polymer flexible film substrate, belonging to the field of precision and ultra-precision machining technology. A method for preparing a polymer flexible film, the method comprises coating a polymer on an ultra-smooth substrate and solidifying it to obtain a polymer film; vitrifying the polymer film; and grinding the surface of the vitrified polymer film. The method of the present invention realizes the mechanical processing of a high-precision polymer flexible film, improves the precision of the polymer film, and uses a mechanical processing method that does not rely on the precision of the template, thereby improving the processing efficiency.

Description

A kind of preparation method of polymer flexible film

technical field

The invention relates to a preparation method of a polymer flexible film, in particular to a coating-ultra-low temperature grinding compound preparation method of a high-precision polymer flexible film substrate, belonging to the technical field of precision and ultra-precision processing.

Background technique

Flexible electronic technology is an emerging electronic technology that fabricates organic or inorganic material electronic devices on flexible and ductile plastic or thin metal substrates. With the further development of flexible electronics research and the continuous improvement of the preparation process of flexible electronic devices, related flexible electronic products will be greatly enriched and flood the market in the future. Significant impact.

Flexible electronics technology has shown great development potential in the fields of solar cells, electronic skin, flexible display and lighting. Flexible display and lighting products have gradually become the representatives of the new generation of products due to their advantages of impact resistance, shock resistance, light weight, small size and easy portability. Taking Organic Light-Emitting Diode (OLED) as an example, because of its self-illumination, no need for backlight, high contrast, thin thickness, wide viewing angle, fast response speed, can be used for flexible panels, and has a wide temperature range It is applied to flexible lighting and display devices, and is considered to be the next generation of emerging lighting display application technology.

Polymer flexible films have good physical and chemical properties, and have better biocompatibility, electrical insulation, and thermal isolation than silicon-based materials. Commonly used flexible film materials include polydimethylsiloxane (PDMS), polyethylene terephthalate, polycarbonate, etc., and their thickness needs to be controlled in the range of tens of microns to hundreds of microns according to actual needs. In the actual application process, polymer flexible films not only need to withstand large deformations such as stretching and curling, but also need to provide a flat surface for the processing of the upper structure. Performance has a significant impact.

Contents of the invention

The purpose of the present invention is to provide a polymer flexible film grinding compound preparation process to solve the problem of unsatisfactory surface shape and surface roughness in the process of polymer film processing and preparation. The method of the invention adopts coating and ultra-low temperature grinding to compositely process the polymer without designing a special template, and is also suitable for various batch production and development of multi-variety and new products.

A preparation method of polymer flexible film, described method is:

Coating polymer on an ultra-smooth substrate and curing it to obtain a polymer film; vitrifying the polymer film; grinding the surface of the vitrified polymer film,

Wherein, the surface accuracy PV value of the ultra-smooth substrate is 5 μm to 10 μm, and the surface roughness is less than 5 nm; the polymer is a high molecular polymer with a glass transition temperature lower than -20°C.

In the above technical solution, preferably, the polymer film is vitrified by contacting the polymer film with liquid nitrogen.

Further, the surface of the vitrified polymer film is subjected to grinding treatment while maintaining the liquid nitrogen in contact with the surface of the polymer film.

In the above technical solution, further, the polymer film after the grinding treatment is placed under normal temperature and pressure to obtain the target polymer film.

In the above technical solution, the ultra-smooth substrate is a substrate material that can be polished. After processing, its surface shape and roughness can reach the surface shape accuracy PV (Peak Value) value of 5 μm to 10 μm, and the surface roughness Less than 5nm, such as silicon substrates, glass substrates, etc.

In the above technical scheme, the polymer is a thermosetting polymer, which is in a liquid state at normal temperature and can be cured after heating. Preferably, the polymer is polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA ), polyvinyl chloride (PVC).

In the above-mentioned technical scheme, when the polymer is coated on the substrate, the liquid polymer itself can be used directly, or the solution formed after the polymer is dissolved in a solvent can be used, which is a prior art in this field. Those skilled in the art can use the method disclosed in the prior art to prepare a polymer film on a substrate to complete the above operations.

In the above technical solution, it is preferable to coat the polymer on the ultra-smooth substrate by means of spin coating on the ultra-smooth substrate.

Further, it is preferable to spin-coat the polymer on the ultra-smooth substrate by using a coater, the speed of the coater is 500r/min-9000r/min; the curing temperature is 30°C-95°C, and the curing time is at least 1 hour.

The preparation method of the flexible polymer film of the present invention preferably grinds the surface of the vitrified polymer film, so that the PV value of the surface shape accuracy of the polymer film surface is less than 1 μm, and the surface roughness is less than 10 nm.

The preparation method of the flexible polymer film of the present invention preferably uses an ultra-precision numerical control grinder to process the surface shape and surface roughness of the vitrified polymer film.

Further, the grinding can use ultra-precision milling equipment with grinding wheels or grinding heads of different meshes to grind the vitrified polymer film so that the surface shape accuracy is less than 1 μm and the surface roughness is less than 10 nm.

The preparation method of the polymer flexible film of the present invention preferably performs the step of vitrification on the surface of the polymer film in the following vitrification device:

The vitrification device includes a box, the box has a built-in container, and the container is provided with a side plate and a bottom plate, and the bottom plate is fixed to the bottom plate of the box; the height of the side plate of the container and the side plate of the box is Same, used to support the box cover; the box cover is made of transparent material, and a processing hole is provided in the center of the box cover, and the processing hole is used to allow the grinding tool to enter the container for processing; the container The central part of the base plate is fixed to the stage, and the two sides of the stage are fixed to the pressure strips through threaded connection parts.

Further, the substrate on which the polymer film is attached is fixed on the stage with a bead, and fastened with a screw connection part; liquid nitrogen is poured into the container at a speed of 0.5 L/min until the polymer film is submerged Let stand for 3-5 minutes.

The above-mentioned vitrification device can realize vitrification by immersing the sample to be processed in liquid nitrogen, and can also fix the sample to be processed to avoid the influence of ultra-low temperature.

A preferred technical scheme of the preparation method of polymer flexible film of the present invention is:

(1) Use an ultra-precision polishing machine to process an ultra-smooth spin-coated substrate, control the PV value of its surface shape accuracy to 5 μm to 10 μm, and the surface roughness to be less than 5 nm;

(2) Spin-coat the polymer film on the substrate prepared in step (1) using a coater, and cure it, the curing temperature is 30°C to 95°C, and the curing time is at least 1 hour;

(3) Use a vitrification device to carry out "vitrification" treatment of the polymer film;

(4) Utilize ultra-precision grinding equipment to process the surface shape and surface roughness of the vitrified polymer film surface;

(5) Return to room temperature to obtain a polymer film with target surface shape accuracy and surface roughness.

Beneficial effects of the present invention: the method of the present invention realizes the mechanical processing of high-precision polymer flexible films, improves the precision of polymer films, and uses the mechanical processing method without depending on the precision of the template, thereby improving the processing efficiency. Compared with the prior art, the method for compounding and preparing high-precision polymer films of the present invention has the following advantages: 1, through the preparation of high-precision spin-coated substrates, it is guaranteed to have high dimensional accuracy and high surface quality spin-coated substrates, which is Machining of polymer films reduces machining allowances. 2. The present invention can realize high-efficiency and precise composite preparation of polymer flexible film materials in an ultra-low temperature environment, and effectively improve efficiency.

Description of drawings

Fig. 1 is the schematic diagram of vitrification device;

Figure 2 is a schematic diagram of the ultra-low temperature grinding platform;

Fig. 3 is the surface height characteristic after the normal temperature processing of embodiment 1 polymer, wherein, the abscissa in the figure is the distance from the zero point in the X-axis direction, and the zero point is the center of the circular polymer film obtained by spin coating;

Fig. 4 is the comparison of the surface height characteristics between the original surface of the polymer in Example 1 and the surface after ultra-low temperature grinding, wherein the surface height after the ultra-low temperature grinding is measured by placing the polymer film after grinding at normal temperature;

Fig. 5 is the comparison of the surface height characteristics between the original surface of the polymer in Example 2 and the surface height after ultra-low temperature grinding, wherein the measured surface height after ultra-low temperature grinding is measured by placing the polymer film after grinding at normal temperature,

Reference signs are as follows: 1. Box cover, 2. Box body, 3. Bead, 4. Threaded connection part, 5. Stage, 6. Container, 7. Electric spindle, 8. Knife handle, 9. Liquid nitrogen, 10. Force sensor, 11. Grinding head, 12. Ultra-precision machine tool, 13. Rack.

Vitrification device and grinding device used in the following examples, as shown in Figures 1 and 2,

Described vitrification device comprises box body 2, and described box body 2 is built-in container 6, and described container 6 is provided with side plate and bottom plate, and described bottom plate is fixed with the bottom plate of box body; The side plates of the body have the same height and are used to support the case cover 1; the case cover 1 is made of transparent material, and a processing hole is provided in the center of the case cover 1, and the processing hole is used to allow the grinding tool to enter the The processing is carried out in the container 6; the central part of the bottom plate of the container 6 is fixed with the stage 5, and the two sides of the stage 5 are fixed with the bead 3 through the screw connection part 4. The threaded connection part 4 is a screw.

The vitrification device is placed on the force sensor 10, the force sensor 10 is placed on the frame 13 of the ultra-precision machine tool 12, the grinding head 11 of the ultra-precision machine tool 12 is fixed on the tool handle 8, and the tool handle is connected to the electric spindle 7. The grinding head 11 penetrates into the container 6 to process the polymer film.

detailed description

Embodiment one

In the OLED manufacturing process, the substrate is required to be flat to reduce the impact of "unevenness" on the display of the device. Therefore, the global film thickness uniformity and local surface flatness are highly required. A relatively flat substrate can greatly improve the performance of the device. The luminescent performance of the substrate film is usually used with a film thickness of 10-200 μm, and the thickness uniformity is less than 2 μm. At the same time, some researchers have proposed that when the surface roughness (Ra) of the film is less than 0.5nm, it will provide a better substrate for the subsequent sputtering of the metal layer of 0.5-1.0nm, which can improve the color display clarity of OLED devices , which is more conducive to the preparation of OLED devices with good display performance and flexible properties.

The PDMS polymer thin film used to prepare the OLED can be obtained by the spin coating-ultra-low temperature grinding composite preparation method.

The specific processing steps are as follows:

(1) Obtain an ultra-smooth spin-coated substrate. In this implementation case, a silicon wafer is selected as the substrate, and the silicon wafer is finished by polishing, so that the PV value of the surface shape accuracy is less than 10 μm, and the surface roughness Ra is less than 0.5 nm, ultrasonically cleaned before spin-coating to obtain a clean and smooth spin-coated substrate;

(2) Mix the silicone rubber prepolymer Sylgard 184 with the curing agent (Dow Corning, USA) in a ratio of 10:1, and stir evenly, vacuumize to make it free of air bubbles, and use a homogenizer to spin coat, spin coat Thickness 15μm, rotation speed 3000r/min, rotation 120s, heating and curing in 90℃ oven;

(3) Take out the cured polymer film, use a flatness meter and a white light interferometer to measure its surface shape accuracy of 1 μm and surface roughness of 0.01 μm; the surface shape accuracy is required to be less than 0.7 μm, and compare with the demand, and estimate the removal amount 0.3 μm.

(4) Clamp the substrate with the polymer film attached on the stage 5 of the vitrification device, pour liquid nitrogen into the container 6 at a speed of 0.5 L/min, and pour it for 5 minutes until the film material is submerged , let stand for 5 minutes;

(5) After the film is vitrified, use an ultra-precision grinding head for grinding, so that the surface shape of the film is less than 0.7 μm and the surface roughness is less than 10 nm. Return to room temperature to obtain a polymer film with target surface shape precision and surface roughness.

The surface shape characteristics of the surface vitrified PDMS after grinding in the ultra-low temperature environment of liquid nitrogen can be seen from Figure 3 and Figure 4, the PV value is reduced to 0.02 μm, the surface roughness Ra is 0.008 μm, the surface of this sample The quality is better than that of the film surface obtained by the spin coating method.

Embodiment two

The PMMA polymer film used to prepare the solar thin film cell can be obtained by the spin coating-ultralow temperature grinding composite preparation method.

The specific processing steps are as follows:

(1) Obtain an ultra-smooth spin-coated substrate. In this implementation case, a silicon wafer is selected as the substrate, and the silicon wafer is finished by polishing, so that the PV value of the surface shape accuracy is less than 10 μm, and the surface roughness Ra is less than 0.5 nm, with ultrasonic cleaning before spin-coating, obtains clean and smooth spin-coated substrate, identical with embodiment one;

(2) PMMA particles are dissolved in the anisole solution to prepare a PMMA solution with a PMMA content of 6%, and spin-coated with a homogenizer, and stirred evenly, and spin-coated with a homogenizer, with a spin-coating thickness of 30 μm , rotate at 1000r/min, rotate for 120s, heat and cure in an oven at 90°C;

(3) Take out the cured polymer film, measure its surface shape accuracy of 3 μm and surface roughness of 0.01 μm with a flatness meter and a white light interferometer, and require the surface shape accuracy to be less than 1 μm, and compare it with the requirement, and estimate the removal amount as 2 μm.

(4) Clamp the substrate with the polymer film attached on the stage 5 of the vitrification device, pour liquid nitrogen into the container 6 at a speed of 0.5 L/min, and pour it for 5 minutes until the film material is submerged , let stand for 5 minutes;

(5) After the film is vitrified, use an ultra-precision grinding head for grinding, so that the surface shape accuracy of the film is less than 0.7 μm and the surface roughness is less than 10 nm. Return to room temperature to obtain a polymer film with target surface shape precision and surface roughness.

The surface shape characteristics of the vitrified PMMA after grinding in the ultra-low temperature environment of liquid nitrogen can be seen from Figure 5, the PV value is reduced to 0.01 μm, and the surface roughness Ra is 0.005 μm. The surface quality of this sample is better than Film surface obtained by spin coating method.

Embodiment Three

The polyvinyl chloride (PVC) polymer used for auxiliary medical supplies can also be obtained by the spin coating-ultra-low temperature grinding composite preparation method. The specific processing steps are as follows:

(1) Obtain an ultra-smooth spin-coated substrate. In this implementation case, a silicon wafer is selected as the substrate, and the silicon wafer is finished by polishing, so that the PV value of the surface shape accuracy is less than 10 μm, and the surface roughness Ra is less than 0.5 nm, before spin-coating, use ultrasonic cleaning to obtain a clean and smooth spin-coated substrate, which is the same as in Examples one and two;

(2) Dissolve PVC particles in cyclohexanone or tetrahydrofuran to prepare a solution with a PVC content of 15%, and spin-coat with a homogenizer, and stir evenly, and spin-coat with a homogenizer, with a spin-coating thickness of 20 μm , rotating at 2000r/min, rotating for 100s, heating and curing in an oven at 90°C;

(3) Take out the cured polymer film, measure its surface shape accuracy of 3.7 μm and surface roughness of 0.01 μm with a flatness meter and a white light interferometer, and require the surface shape accuracy to be less than 1 μm, compare with the demand, and estimate the removal amount is 2.7 μm.

(4) Clamp the substrate with the polymer film attached on the stage 5 of the vitrification device, pour liquid nitrogen into the container 6 at a speed of 0.5 L/min, and pour it for 5 minutes until the film material is submerged , let stand for 5 minutes;

(5) After the film is vitrified, use an ultra-precision grinding head for grinding, so that the surface shape accuracy of the film is less than 0.8 μm and the surface roughness is less than 10 nm. Return to room temperature to obtain a polymer film with target surface shape precision and surface roughness.

The surface shape characteristics of the surface vitrified PVC after grinding in the liquid nitrogen ultra-low temperature environment, the PV value is reduced to 0.3 μm, and the surface roughness Ra is 0.007 μm. The surface quality of this sample is better than that of the film surface obtained by the spin coating method.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (10)

1. a kind of preparation method of polymer flexibility film, it is characterised in that：Methods described is：

Coated polymer and solidify it on ultra-smooth substrate, obtain thin polymer film；Make thin polymer film that vitrifying to occur； Surface to vitrified thin polymer film carries out grinding treatment,

Wherein, the surface figure accuracy PV values of the ultra-smooth substrate are 5 μm~10 μm, and surface roughness is less than 5nm；The polymer High molecular polymer for glass transition temperature less than -20 DEG C.

2. method according to claim 1, it is characterised in that：Thin polymer film is contacted with liquid nitrogen sends out thin polymer film Raw vitrifying.

3. method according to claim 2, it is characterised in that：Maintaining what liquid nitrogen was in contact with the surface of thin polymer film In the case of, the surface to vitrified thin polymer film carries out grinding treatment.

4. method according to claim 1, it is characterised in that：The polymer is dimethyl silicone polymer, poly- methyl-prop E pioic acid methyl ester, polyvinyl chloride.

5. method according to claim 1, it is characterised in that：It is described to be surpassed by the way of spin coating on ultra-smooth substrate Coated polymer in smooth substrate.

6. method according to claim 1, it is characterised in that：Using sol evenning machine on ultra-smooth substrate spin on polymers, Spin coating machine speed is 500r/min~9000r/min；The temperature of the solidification is 30 DEG C~95 DEG C, at least 1 hour hardening time.

7. the method according to claim 1 or 3, it is characterised in that：Surface to vitrified thin polymer film is carried out Grinding is processed, and makes the surface figure accuracy PV values of polymeric film surface less than 1 μm, and surface roughness is less than 10nm.

8. method according to claim 1, it is characterised in that：There is vitrified step and exist in the polymeric film surface Carried out in following vitrifying devices：

The vitrifying device includes casing (2), and the casing (2) built-in receptacle (6), the container (6) is provided with side plate and bottom Plate, the base plate is mutually fixed with the base plate of casing；The side plate of the container (6) is highly identical with the side plate of casing, for supporting Case lid (1)；The case lid (1) is obtained by transparent material, and is provided with processing hole in the centre of case lid (1), and the processing hole is used Enter when making grinding knife tool in processing and be processed in container (6)；The baseplate centre portion of the container (6) fixes objective table (5), (5) two sides of objective table are connected through a screw thread the fixed press strip (3) of part (4).

The substrate press strip (3) of polymer attached film thereon is fixed on objective table (5), and with threaded connection element (4) Fastening；Liquid nitrogen is poured into container (6) with the speed of 0.5L/min, untill thin polymer film is submerged, 3~5 points is stood Clock.

9. method according to claim 1, it is characterised in that：Using ultraprecise numerically control grinder to vitrified polymer Film carries out face shape and surface roughness working process.

10. method according to claim 1, it is characterised in that：The ultra-smooth substrate is silicon substrate, glass substrate.