Composite film containing glass layer and preparation method and application thereof

Abstract

The invention relates to a composite film containing a glass layer and a preparation method and application thereof, and relates to the technical field of composite film preparation. The composite film containing the glass layer comprises a base film and the glass layer, the glass layer is obtained by coating the surface of the base film with glass melt, and the base film comprises a polymer film or a surface modified polymer film. The glass layer in the composite film is obtained by coating a continuous and homogeneous melt, and gaps or bubbles are fully removed in advance, so that the composite film containing the compact and continuous glass layer with good adhesive force can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of composite film preparation, in particular to a composite film containing a glass layer and a preparation method and application thereof. Background Art

[0002] High-barrier films are primarily used in food packaging, pharmaceutical packaging, and electronic device packaging, protecting food, pharmaceuticals, or electronic devices from corrosive environments such as water vapor and oxygen. Materials capable of achieving high barrier properties generally possess dense atomic structures, and currently, high-barrier films typically rely on dense inorganic layers. While metals possess excellent barrier properties due to the dense atomic arrangement within their crystals, their electrical conductivity and opacity significantly limit their applicability.

[0003] With the development of materials science, the heat resistance temperature of some organic polymer materials has exceeded the processing temperature of inorganic glass, which provides the possibility of processing glass layers on organic polymer substrates.

[0004] Glass is an important high-barrier packaging material. Glass with a thickness of less than 1mm is generally referred to as ultra-thin glass, and some companies have already achieved ultra-thin glass products with thicknesses of only tens of microns. Ultra-thin glass is generally manufactured using processes such as float, overflow down-draw, and slot-draw. The production equipment required is more expensive, the process is more complex, and the technical requirements are higher than those for ordinary flat glass. For example, float glass requires a side-drawing machine to draw the molten glass over a molten tin bath, gradually thinning it. Currently, the industry can produce ultra-thin float glass with a thickness of 120μm. Furthermore, subsequent processing steps such as cutting, thinning, ion implantation, and microcrystal growth are required to obtain the final ultra-thin glass product. This method is associated with high energy consumption, low production efficiency, high costs, and chemical pollution. While ultra-thin glass has improved brittleness compared to ordinary thick glass, it remains relatively fragile compared to polymer materials. Once a crack appears in ultra-thin glass, it will rapidly expand under stress, causing the glass to shatter and fail, significantly reducing its barrier and packaging properties. Therefore, how to overcome the fragility of ultra-thin glass is a key issue that needs to be urgently solved as a high-barrier packaging material.

[0005] At present, dense inorganic barrier layers are mainly prepared by chemical vapor deposition methods. Among them, plasma enhanced chemical vapor deposition (PECVD) and atomic layer deposition (ALD) are two representative deposition technologies. The conventional CVD deposition temperature is 700-900°C, which is difficult to use for heat-sensitive polymer substrates. PECVD uses plasma to ionize reactants into active particles, so that deposition can be achieved at a lower temperature (usually 300-400°C). ALD technology uses surface self-limiting reactions to achieve precise atomic-level thickness control, and can prepare ultra-thin inorganic layers with high density, high purity and high uniformity. However, PECVD and ALD equipment are expensive, have low deposition rates, and are costly, which is not conducive to large-scale applications. Summary of the Invention

[0006] In response to the above problems, the present invention provides a composite film containing a glass layer, in which the glass layer is obtained by continuous and homogeneous melt coating. By fully eliminating gaps or bubbles in advance, a composite film containing a dense, continuous, and well-adhesive glass layer is obtained.

[0007] To achieve the above object, the present invention provides a composite film containing a glass layer, comprising a base film and a glass layer, wherein the glass layer is obtained by coating a glass melt on the surface of the base film, and the base film comprises a polymer film or a surface-modified polymer film.

[0008] In this technology, the inventors hope to take advantage of the excellent flexibility, film-forming properties and high heat resistance of some high-temperature resistant polymer materials, and prepare a dense inorganic glass layer on their surface by coating a glass melt, thereby obtaining a composite film with both flexibility and high barrier properties. Common high-temperature resistant polymer materials include polyimide (PI), polybenzoxazole (PBO), polybenzimidazole (PBI), polybenzothiazole (PBT), polyoxadiazole (POXA), polyquinazolinedione (PQZO), polyquinoxaline (PQ), polyphenylquinoxaline (PPQ), etc. Unlike the traditional process of firing enamel and glass enamel on metal substrates at high temperatures (usually >800°C), the heat resistance temperature of organic polymer substrates usually does not exceed 600°C. Therefore, in order to prepare a glass coating on a polymer film, it is necessary to use a glass formula with fusible characteristics and a highly heat-resistant polymer to match the forming temperature of the glass with the heat resistance temperature of the polymer substrate. At the same time, it is also necessary to design a reasonable coating structure and forming process to obtain a dense, continuous, and well-adhesive glass coating while ensuring that the polymer substrate is not damaged by high temperature.

[0009] In previous studies, the inventors prepared composite films by coating glass paste or glass powder on a polymer substrate and then treating it at high temperature. However, this method has some problems:

[0010] (1) Glass slurry (suspension) itself is an unstable system, in which glass particles cannot be evenly dispersed, which makes it difficult to prepare a powder layer of uniform thickness.

[0011] (2) Due to the large specific surface area, the powder particles in the glass paste will adsorb solvent molecules during the preparation and storage process. The organic solvent cannot be completely removed during high-temperature treatment, and carbonization and blackening will occur, which will damage the optical properties of the film and the formation of a dense structure. Some solvents, such as water, will react with some components in the glass. When the powder is heated again, it cannot be fully vitrified, and crystals will form inside, resulting in the glass having a frosted appearance and reduced optical transparency.

[0012] (3) High-temperature resistant polymers are generally insulators. It is difficult to spread the electrostatically charged powder particles evenly and densely on their surface by relying on the electric field after being energized, like a metal plate. It is difficult to prepare a powder layer of uniform thickness.

[0013] (4) Glass powder shrinks in volume during high-temperature melting, and gaps are likely to remain between the particles, which is not conducive to obtaining a completely dense glass layer, resulting in poor barrier properties of the composite film.

[0014] (5) In order to obtain a continuous glass coating, the thickness of the powder layer needs to be increased. However, the thick powder layer is prone to cracking and peeling during drying, and needs to be repaired and filled through multiple cycles of coating and sintering, which greatly prolongs the preparation time and causes additional thermal damage to the substrate.

[0015] (6) The self-leveling of the glass melt to achieve uniform spreading requires very high fluidity of the glass melt, and the glass components that can meet the requirements are very limited. Improving the fluidity of the melt requires the introduction of alkali metal ions or disconnecting some of the glass network connections, which generally deteriorates the water resistance and chemical stability of the glass.

[0016] Therefore, the inventors propose the following technical solutions:

[0017] (1) The glass is pre-prepared into a continuous, homogeneous melt, eliminating the need for a suspension (slurry). This avoids the instability of the glass slurry encountered in prior art, and eliminates the difficulty of producing a powder layer of uniform thickness. Furthermore, because no solvent is used, organic solvent molecules are not adsorbed, and carbonization and blackening problems do not occur; nor does the problem of solvent-induced crystallization occur.

[0018] (2) The gas and voids in the glass melt are removed before coating to avoid the problem of residual voids between powders or particles during high-temperature treatment in the prior art.

[0019] (3) The melt is formed into a thin layer through a mechanical coating process. During the coating process, the mechanical force of the die head, scraper, etc. is used to achieve uniform spreading of the glass layer, and work is done on the layer formation process of the thin layer. It does not rely solely on the self-leveling of the melt to obtain a flat surface, reducing the dependence on low-viscosity glass melt, so that higher viscosity, more stable and water-resistant glass components can be used.

[0020] (4) Glass requires long-term high-temperature heat treatment to fully remove voids and obtain good fluidity, while polymers only need to meet the stress requirements of the composite film after the coating is cooled to room temperature. The polymer does not need to accompany the glass to withstand the harsh high-temperature environment. The heating of the two should be distinguished. By heating the glass melt and the polymer substrate separately and at different temperatures, the manufacturing strategy of shortening the time the glass and substrate are heated at the same time can greatly reduce the thermal damage to the polymer substrate caused by high temperature during the forming process;

[0021] (5) By utilizing the interfacial effect of the polymer substrate surface, the formation of the glass layer follows the interfacial film-forming mechanism, which is more conducive to obtaining an ultra-thin glass layer with uniform thickness compared to the independent film-forming mechanism.

[0022] In one embodiment, the surface modified polymer film includes a polymer film and a modified layer, the modified layer covers the surface of the polymer film, the modified layer includes an inorganic layer, the inorganic layer includes at least one of a wetting layer having a surface energy close to that of a glass melt, an anti-corrosion layer having strong bond energy, an adhesive layer having strong bonding effect with a substrate, and a thermal insulation layer.

[0023] The provision of the modified layer can further improve the wettability and bonding strength between the glass layer and the polymer film, and improve the corrosion resistance and heat resistance of the polymer film.

[0024] In one embodiment, the difference in surface energy between the wetting layer in the polymer film or surface-modified polymer film and the glass melt is ≤ 200 mJ m -2 .

[0025] In one embodiment, the strong bond energy is a bond energy ≥ 300 kJ mol -1 .

[0026] In one embodiment, the strong adhesion is an adhesive adhesion strength ≥ 2 MPa.

[0027] In one embodiment, the thermal conductivity of the thermal insulation layer is less than 10 W m -1 K -1 .

[0028] In one embodiment, the raw material of the glass melt includes fusible glass, and the maximum heat-resistant temperature of the base film is greater than or equal to the coating temperature of the glass melt.

[0029] By controlling the maximum heat-resistant temperature and making full use of the excellent heat resistance of certain high-performance polymers, it is possible to directly form a glass layer on their surface.

[0030] In one embodiment, the softening temperature of the fusible glass is ≤550°C, and the viscosity of the fusible glass corresponding to the softening temperature is 10 6.6 Pa s.

[0031] The present invention also provides a method for preparing the composite film, comprising the following steps: at a predetermined temperature, making the base film straight in the width direction; heating the raw material of the glass melt to above the de-gap temperature to remove the voids in the glass melt; at a coating temperature, coating the glass melt on the surface of the base film; and performing heat treatment to obtain a composite film containing a glass layer.

[0032] The above-mentioned preparation method can manufacture flexible high-barrier composite films at low cost, high efficiency, continuously, and on a large scale. It can promote the industrial development of polymer-based glass-lined technology and produce new functional film materials with practical value. The above-mentioned linear shape is the geometric form of the polymer film or surface-modified polymer film in the coating area due to the mechanical structure. This shape is conducive to achieving a uniform thickness of the glass melt. It is understandable that in the actual production process, the above-mentioned step of making the base film linear in the width direction may not achieve a perfect linear shape due to factors such as increased temperature or insufficient machining precision. Therefore, slight deformation caused by temperature changes or machining is allowed, but the deformation should not significantly affect the uniformity of the coating layer thickness. The coating area includes but is not limited to a straight line or a nearly straight line area.

[0033] In one embodiment, room temperature ≤ the predetermined temperature ≤ process temperature, the process temperature is higher than the coating temperature, and the coating temperature is the viscosity of the glass melt between 0.01 and 10 6.6 Pa s between any temperature corresponding to the temperature, the gap temperature is the viscosity of the glass melt is 10 5 Temperature at Pa s.

[0034] The aforementioned predetermined temperatures refer to the temperatures of various components in the coating system, derived through theoretical derivation and experimental optimization. These include, but are not limited to, the temperatures of multiple components in the coating system, such as the extruder (front, middle, and back), die head, support rollers, guide plates, scrapers, squeegees, annealing zones, etc. In other words, these are the temperatures set for the system to ensure normal operation of the equipment in the coating system.

[0035] The above-mentioned process temperature refers to the maximum operating temperature of the heating element itself in the coating system. Compared with the predetermined temperature, it is a higher temperature existing in the coating system. There are usually multiple heating elements distributed in different components in the coating system. Each heating element has its own operating temperature, and the process temperature specifically refers to the highest temperature value among all these heating elements. For example, a heating element acts as a heat source to provide heat to a system component. The temperature of the component surface is one of the predetermined temperatures, and the temperature of the heating element is the process temperature of the component. Since there are multiple heating elements in the system and the heating elements are usually not heated uniformly, the process temperature specifically refers to the highest temperature point of all the heating elements in the entire system. This distinction between the predetermined temperature and the process temperature enables the temperature state of the system to be fully summarized, which helps to accurately describe the coating process.

[0036] In one embodiment, the method for preparing the composite membrane comprises the following steps:

[0037] Step (1) basement membrane treatment:

[0038] The high-temperature resistant polymer film or the surface-modified high-temperature resistant polymer film is tensioned and secured using a film tensioning device or rollers so that the film has a straight surface profile in the coating area across its width at at least one temperature between room temperature and the process temperature. The maximum heat-resistant temperature of the high-temperature resistant polymer film or the surface-modified high-temperature resistant polymer film is higher than the coating temperature of the molten glass.

[0039] To ensure that the straight surface contour is maintained during coating, support rollers, support plates or support lines can be used on the other side of the film. When using support rollers or support plates, prefabricated deformations can be used to ensure that the mechanical structure remains straight during operation.

[0040] The surface-modified polymer film includes: modifications made to improve the wettability of the glass melt to the high-molecular polymer film, so that the surface of the film is covered with an inorganic layer with a surface energy similar to that of the glass melt; modifications made to improve the bonding strength of the glass layer to the polymer film, so that the surface of the film is connected to the inorganic layer with strong bonding strength to the glass; modifications made to prevent the glass melt from corroding the polymer film, so that the surface of the film is covered with a corrosion protection layer with strong bond energy; modifications made to prevent the high temperature of the glass melt from damaging the polymer film, so that the surface of the film is covered with a heat-insulating layer.

[0041] Step (2) preparing a glass melt:

[0042] The fusible glass powder or particles are heated in a container to above the deinterstitial temperature to fully remove voids and bubbles to obtain a homogeneous and dense glass melt. The deinterstitial temperature is the viscosity of the glass melt of 10 5The temperature corresponding to the extruder at 100 Pa s. A metering pump can be connected to the end of the extruder to achieve precise metering of the material. The end of the extruder, melt pump, or metering pump is connected to the die head, scraper, or melt delivery pipeline.

[0043] Another option is to directly use fusible glass batch materials instead of fusible glass powder or granules. The batch materials are heated to or above the melting temperature, and mechanically extruded or stirred to remove voids in the powder or granules and small molecules generated during the melting process, resulting in a bubble- and pore-free glass melt. The melting temperature refers to the temperature required for the batch materials to undergo physical and chemical changes such as dehydration, decomposition, and combination, and is generally higher than the coating temperature.

[0044] The container includes an extruder or other devices that can provide a high-temperature melt containing function, such as a hot melt adhesive machine, a high-temperature metering pump, a crucible (with a heating device), etc.

[0045] Step (3) Glass melt coating:

[0046] The straight or nearly straight surface area of ​​the stretched and fixed polymer film is coated with glass melt; to ensure that the coated area can remain straight when subjected to the extrusion force during coating or the weight of the melt, support can be provided on the other side of the film; during the coating process, the optimized design of structures such as the support roller, coating die head, and scraper (prefabricated deformation, etc.) is conducive to obtaining a glass coating with uniform thickness.

[0047] Step (4) heat treatment:

[0048] The polymer film coated with the glass melt is heat treated to obtain a composite film containing a glass layer. The heat treatment includes annealing, cooling, quenching, and laser treatment. The purpose of the annealing treatment is to eliminate stress in the glass layer and / or the flexible substrate film. Generally, the annealing treatment is carried out at the strain point temperature of the glass (corresponding to a glass viscosity of 10 13.5 Pa s) to glass transition temperature (corresponding to glass viscosity 10 12 The heat treatment can also include quenching to develop the glass layer into a tempered glass layer, improving its surface hardness and scratch resistance. Laser irradiation can also be used to extend the flow time of the molten glass, resulting in a glass layer with lower surface roughness. Short-wavelength lasers act only on the surface of the glass, reducing thermal damage to the polymer film caused by high temperatures.

[0049] In one embodiment, the coating comprises at least one of: engraved wheel coating, reverse coating, slot die coating, lip coating, blade coating, scraper coating, plate coating, liquid cavity blade coating, rod coating, air blade coating, and dimple coating;

[0050] The heat treatment includes at least one of annealing, cooling, quenching, and laser irradiation treatment.

[0051] In one embodiment, the annealing temperature is the strain point temperature of the glass (10 13.5 Pa s) to glass transition temperature (10 12 Any temperature between 1000 and 2000 Pa s).

[0052] The present invention also provides the use of the composite film in preparing a functional film, wherein the functional film is a high barrier film, an impact-resistant film and / or a hardened film, and the functional film is used for packaging or encapsulation.

[0053] In one embodiment, the functional film includes at least one of a food packaging film and a medicine packaging film, and the packaging film includes at least one of a flexible electronic device packaging film and an integrated circuit packaging film.

[0054] The present invention also provides a film for packaging or encapsulation, comprising the composite film.

[0055] The present invention also provides a device packaging method, comprising the following steps: covering the film on the upper surface and / or lower surface of the device, setting a packaging wall on the periphery of the device, connecting the packaging wall to the film on the upper surface and / or lower surface to form a sealed cavity, and the device is wrapped in the sealed cavity.

[0056] In one embodiment, the raw material of the packaging wall includes low-temperature sintered ceramics, and the connection between the packaging wall and the thin film on the upper surface and / or the lower surface is achieved by sintering.

[0057] In one embodiment, the low-temperature sintered ceramic is sintered below 600°C.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The present invention discloses a composite film containing a glass layer, its preparation method, and its application. The glass layer in the composite film is obtained by continuous, homogeneous melt coating, with voids or bubbles fully removed beforehand, resulting in a composite film containing a dense, continuous, and well-adhesive glass layer. This preparation method enables the low-cost, high-efficiency, continuous, and large-scale production of flexible, high-barrier composite films, promoting the industrialization of polymer-based glass-lined technology and enabling the preparation of novel functional film materials with practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 Schematic diagram of the forming part structure of the equipment in Example 1, wherein 1 is the die, 2 is the glass layer, 3 is the support roller, 4 is the polyimide film, 5 is the polyimide film, 6 is the glass melt, and 7 is the die lip;

[0061] Figure 2 Schematic diagram of the forming part structure of the equipment in Example 2, wherein 8 is a glass layer, 9 is a support roller, 10 is a (modified) polyimide film, 11 is a glass melt, and 12 is a lip die;

[0062] Figure 3 Schematic diagram of the forming part structure of the equipment in Example 3, wherein 13 is a glass melt, 14 is a comma scraper, 15 is laser irradiation, 16 is a glass layer, 17 is a support roller, and 18 is a (modified) polyimide film;

[0063] Figure 4 Schematic diagram of linear doctor blade coating in Example 4, wherein 19 is a glass melt, 20 is a support arm, 21 is a linear doctor blade, 22 is a glass layer, 23 is a (modified) polyimide film, and 24 is a base;

[0064] Figure 5 Schematic diagram of scraper blade coating in Example 5, wherein 25 is a (modified) polyimide film, 26 is a tension control roller, 27 is a scraper, 28 is a glass layer, 29 is a support plate, 30 is a fixture, 31 is a grating ruler, and 32 is a base;

[0065] Figure 6 Schematic diagram of liquid chamber doctor blade (micro-gravure printing) coating in Example 6, wherein 33 is a melt chamber, 34 is a (modified) polyimide film, 35 is a driving roller, 36 is a glass layer, and 37 is a coating roller. DETAILED DESCRIPTION

[0066] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0068] source:

[0069] Unless otherwise specified, the reagents, materials, and equipment used in this example are all commercially available; and the experimental methods, unless otherwise specified, are all conventional experimental methods in the art.

[0070] Example 1

[0071] The structure of the forming part of the equipment is as follows Figure 1 shown.

[0072] Step (1) Base Film Treatment: Take a colored polyimide film Upilex-S (25 μm thick) with a width of 125 mm. Use a take-up roller to tension the film, and place a heated support roller on the back of the film to ensure that the extrusion force and the weight of the melt during extrusion coating do not damage the straightness of the film coating area and allow the film to be preheated. The support roller and the lip of the slit die are pre-deformed to ensure that under a predetermined temperature condition below 550°C (the predetermined temperature is a set of temperatures between room temperature and process temperature. Those skilled in the art can select a temperature that allows for normal operation based on the conditions of the various equipment and components in the coating system), the die lip and the adjacent support roller area are linear. In particular, the film attached to the support roller is linear in the width direction to ensure that the glass melt can rely on this linear structure to form a glass layer of uniform thickness. The heat resistance temperature of Upilex-S is 500°C higher than the coating temperature.

[0073] Step (2) Preparation of glass melt: colored lead-free fusible glass (softening temperature 380 ° C, the viscosity of fusible glass at the softening temperature is 10 6.6 Pa s) was made into powder and added into a single screw extruder. The end of the extruder was connected to a slit die with a width of 110 mm. The temperature of the extruder was gradually increased in sections until the temperature at the end reached 500°C (higher than the degating temperature of the glass, which is the viscosity of the glass melt of 10 5 As the screw in a single-screw extruder rotates, the material automatically expels the gas trapped in the gap backward, resulting in a dense glass melt. The support roller and the lip of the slot die are both linear in their relative positions.

[0074] Step (3) Glass melt coating: The obtained glass melt is extruded through a slot die to produce a melt film with uniform thickness, and the melt film is brought into contact with the substrate for coating (the coating temperature is such that the viscosity of the glass melt is between 0.01 and 10 6.6 Pa s corresponds to a temperature between 100°C and 500°C (in this embodiment, the coating temperature is 500°C). The substrate film moves at a certain speed. The entire device is placed in a glass isolation cover and protected by nitrogen to prevent dust, water vapor, oxygen, etc. from affecting the process during operation.

[0075] Step (4) Heat treatment: After coating, the composite film is annealed at a temperature equal to the glass transition temperature of glass (330°C), corresponding to a glass viscosity of 10 12 Pa s to eliminate thermal stress in the glass. After annealing, the composite film is cooled to room temperature, rolled up, and packaged.

[0076] The water vapor permeability of the composite film is less than 10 -3 gm-2 day -1 , does not contain heavy metal lead, and can be used to package food and medicine that need to be stored in a dark place.

[0077] Example 2

[0078] The structure of the forming part of the equipment is as follows Figure 2 shown.

[0079] Step (1) Substrate film treatment: Select a 125 mm wide polyimide film Upilex-S and deposit a layer of SiO2 on the film surface by PECVD to improve the wettability of the glass melt to the substrate. The surface energy difference between the surface modified polymer and the glass melt is less than 200 mJ m -2 The film is stretched by a film stretching device, and the geometric shapes of the support roller and the lip die at the coating temperature are ensured to be linear at a predetermined temperature below the process temperature of 600°C (the predetermined temperature is a set of temperatures between room temperature and process temperature. Those skilled in the art can select the temperature for normal operation based on the conditions of the various equipment and components in the coating system) through prefabricated deformation, so as to ensure that the forming area is linear.

[0080] Step (2) Preparation of glass melt: Lead-containing colorless fusible glass (softening temperature ≤ 550 ° C, the viscosity of the fusible glass at the softening temperature is 10 6.6 Pa s, the gap temperature is when the viscosity of the glass melt is 10 5 After being pelletized at a temperature of 100 Pa s, the glass melt is fed into a single-screw extruder. The temperature is raised in stages, reaching 550°C (well above the degating temperature) at the mid-section. The extruder is terminated with a lip die with a 110 mm discharge opening. As the screw rotates, the air between the particles is expelled, resulting in a dense glass melt. After passing through the lip die, the melt is prepared for preforming.

[0081] Step (3) coating of glass melt: coating the glass melt obtained in step (2) on the straight surface area of ​​the film fixed by tension in step (1) (coating temperature is such that the viscosity of the glass melt is between 0.01 and 10 6.6 Pa s between the corresponding temperature), the film moves relative to the material area to complete the coating.

[0082] Step (4) heat treatment: the composite film coated with the glass melt is subjected to quenching and cooling treatment to obtain a composite film with excellent surface hardness (>4H).

[0083] Example 3

[0084] The structure of the forming part of the equipment is as follows Figure 3 shown.

[0085] Step (1) Base film treatment: A polyimide film with a width of 125 mm is selected. The film surface is treated with alkali to open some of the imide rings. After washing with deionized water, an Al2O3 layer is prepared on the film surface by a sol-gel method. The Al2O3 layer has a strong bonding ability with the polyimide, with an adhesive strength of ≥3 MPa, which can improve the adhesive adhesion of the glass layer to the substrate. The film is tensioned using a film tensioning device. Prefabricated deformation ensures that the film is under a predetermined temperature condition below 550°C (the predetermined temperature is a set of temperatures between room temperature and the process temperature. Those skilled in the art can select a temperature that allows normal operation based on the conditions of the various equipment and components in the coating system). The geometric shapes of the support roller and the comma scraper during operation ensure that the forming area is linear. A melt pump is used to feed the melt tank. The heat-resistant temperature of the film is higher than the coating temperature. To ensure the stable performance of the polyimide film under high temperature conditions, the equipment is enclosed in a glass cover to provide a water-free, oxygen-free, and dust-free working environment for the manufacturing process.

[0086] Step (2) Preparation of glass melt: Lead-free colorless fusible glass particles (softening temperature ≤ 450 ° C, the viscosity of fusible glass at the softening temperature is 10 6.6 Pa s) into the melt pump and heated to the working point (10 3 Pa s) temperature (higher than the deinterstitial temperature) to fully remove the gas in the voids and obtain a homogeneous and dense glass melt. The melt is pumped onto an inclined heating plate at a 45-degree angle to the vertical. The heating plate, support rollers, and comma scrapers together form a melt trough with an opening width of 110 mm. A comma scraper is used to ensure uniform material flow across the width of the melt.

[0087] Step (3) coating of glass melt: coating the glass melt of step (2) on the straight surface area of ​​the film fixed by tension in step (1) (coating temperature is the viscosity of the glass melt between 0.01 and 10 6.6 Pa s between the corresponding temperature), the film moves relative to the material area to achieve roll-to-roll continuous coating.

[0088] Step (4) heat treatment: The coated composite film is heat treated by ultraviolet laser irradiation. The short-wave laser acts on the surface of the glass layer, and the heat causes little damage to the base polyimide. This treatment can extend the self-leveling time of the glass melt and obtain a composite film with lower surface roughness.

[0089] The water vapor permeability of the composite film is less than 10 -3 gm -2 day -1 , free of heavy metal lead, colorless and transparent, and can be used for the encapsulation of flexible electronic devices (thin-film solar cells) that require light transmission.

[0090] Example 4

[0091] Step (1) Base film treatment: Select a polyimide film with a width of 125 mm and deposit a layer of Si3N4 on the surface of the film by PECVD. The bond energy of the Si-N bond in Si3N4 is greater than 300 kJ mol -1 This layer can prevent the glass melt from corroding the polyimide substrate. The film is tensioned using a film tensioning device. Prefabricated deformation ensures that the film remains straight across the width of the film at the forming position, while maintaining a predetermined operating temperature below 550°C (a predetermined temperature range between room temperature and the process temperature. Those skilled in the art can select a temperature that allows for normal operation based on the conditions of the various devices and components in the coating system). The support roller and linear scraper maintain a straight line across the film width at the forming position.

[0092] Step (2) Preparation of glass melt: glass ceramic (amorphous glass as the main body, crystalline phase as the auxiliary, a small amount of voids not fully removed, softening temperature ≤ 550 ° C, the viscosity at the softening temperature is 10 6.6 The glass ceramic melt is made into granules by adding a metering pump with a heating and stirring device to obtain a glass ceramic melt and precisely control the melt output flow rate. The glass ceramic contains a small amount of refractory (nanoscale) ceramic particles or crystalline particles. The glass ceramic melt is pumped to the area adjacent to the linear scraper on the surface of the polyimide film for coating. The discharge width of the linear scraper is 110mm. The schematic diagram of the linear scraper coating is shown in the figure. Figure 4 shown.

[0093] Step (3) coating of glass melt: on the straight surface area of ​​the film fixed by tension in step (1), the glass ceramic melt measured in step (2) is coated with a linear scraper (the coating temperature is such that the melt viscosity is between 0.01 and 10 6.6 Pa s between the corresponding temperature), the film moves relative to the scraper to achieve continuous coating.

[0094] Step (4) heat treatment: the coated composite film is slowly cooled to room temperature to obtain a composite film with excellent barrier properties and impact resistance, which can be used for packaging of integrated circuits.

[0095] Compared with other die heads or scrapers and blades, the deformation of the linear scraper after heating is mainly reflected in the length direction, and the thermal expansion deformation in the diameter direction is small. Therefore, the thermal deformation of the mechanical structure is not easy to interfere with the control of the thickness of the glass melt layer. The composition of polyimide and glass is diverse. In order to adapt to a variety of different needs, it is necessary to develop a series of composite films, and the equipment needs to work under different temperature conditions. The price of a single meter-long slit die is more than one million yuan, and it can only adapt to one material system through prefabricated deformation design. The linear scraper in this embodiment can adapt to a variety of different material systems.

[0096] Example 5

[0097] Step (1) Base film treatment: A colorless polyimide film with a width of 125 mm was selected and a TiO2 layer was deposited on the film surface by magnetron sputtering technology. The thermal conductivity of the layer was 0.5 W m -1 K -1 It provides thermal insulation, preventing thermal damage to the polyimide substrate from the molten glass. The film is tensioned using a rewinding and unwinding device, and a support plate is placed on the back of the film to ensure the straightness of the coating area at a predetermined temperature below the process temperature of 550°C (the predetermined temperature is a range between room temperature and the process temperature; those skilled in the art can select a temperature that allows for normal operation based on the conditions of the various equipment and components in the coating system).

[0098] Step (2) Preparation of glass melt: colorless lead-containing fusible glass (softening temperature 380°C, viscosity of fusible glass at softening temperature is 10 6.6 Pa s) into a crucible in a resistance heating furnace and heated to a temperature above the working temperature (higher than the degap temperature, which is the viscosity of the glass melt of 10 5 The air in the gaps was fully removed to obtain a homogeneous glass melt. The hot glass melt was poured into a graphite tank and formed into long strips. After cooling, a glass strip with a length of 110 mm was obtained.

[0099] Step (3) Glass melt coating: Place the glass strip on the heating plate, cover it with a lid, and maintain the temperature in the chamber at 500°C. The glass strip melts and contacts the moving modified polyimide film under the action of gravity. The glass melt is evenly coated on the surface of the polyimide film (the coating temperature is when the viscosity of the glass melt is between 0.01 and 10 6.6 Pa s corresponds to a certain temperature). The schematic diagram of scraper blade coating is as follows Figure 5 shown.

[0100] Step (4) Heat treatment: The coated composite film is annealed at 350°C for 30 minutes to eliminate residual stress. After annealing, the temperature is cooled to room temperature to obtain a colorless and transparent composite film.

[0101] Example 6

[0102] Step (1) Base film treatment: Select a colorless polyimide film with a width of 125 mm, treat the surface of the polyimide film with alkaline solution to open some of the imide rings, wash with deionized water, and then prepare an Al2O3 layer on the film surface by a sol-gel method. The Al2O3 layer has a strong bonding ability with the polyimide, and the adhesive strength is ≥3MPa, which can improve the adhesive strength of the glass melt to the substrate. The film is tightened with a take-up roller, and a drive roller is set on the back of the film to ensure that under a predetermined temperature condition lower than the process temperature of 550°C (the predetermined temperature is a set of temperatures between room temperature and the process temperature. Those skilled in the art can select a temperature that allows normal operation according to the conditions of the various equipment and components in the coating system), the pressure during coating will not damage the straightness of the film in the width direction.

[0103] Step (2) Preparation of glass melt: Lead-free colorless fusible glass batch material (the softening temperature of the obtained glass is ≤550℃, and the viscosity of the fusible glass at the softening temperature is 10 6.6 The glass is then fed directly into an extruder (Pa s), where it undergoes glass melting and degassing. (The melting temperature refers to the temperature required for the batch to undergo physical and chemical changes such as dehydration, decomposition, and combination, and is typically much higher than the temperature used for coating.) The extruder is then connected to a melt chamber, where a micro-concave roller contacts the liquid surface, filling the micro-concave grooves on the roller surface. Because the melt is not cooled to room temperature or broken into powder or granules, this step reduces energy consumption and avoids dust pollution compared to previous solutions.

[0104] Step (3) Glass melt coating: In the linear surface area of ​​the film tensioned and fixed in step (1), the glass melt prepared in step (2) is coated on the colorless polyimide film by micro-gravure printing (the coating temperature is a temperature corresponding to the temperature when the glass melt viscosity is between 0.1-1 Pa s). The micro-gravure roller rotates and the film moves relative to the micro-gravure roller to achieve continuous printing and coating. The schematic diagram of liquid cavity doctor blade (micro-gravure printing) coating is shown as follows: Figure 6 shown.

[0105] Step (4) Heat treatment: The coated composite film is annealed at 350°C for 30 minutes to eliminate residual stress. After annealing, the temperature is cooled to room temperature to obtain a colorless and transparent composite film that can be used for packaging flexible electronic devices (flexible displays or flexible solar devices).

[0106] Example 7

[0107] Low-temperature sintered ceramics are used as side sealing materials for electronic devices. The low-temperature sintered ceramics are borate ceramics with a specific formula of 60wt.% B2O3, 25wt.% SiO2, 10wt.% Al2O3, and 5wt.% ZnO.

[0108] The above raw materials are mixed according to the proportions and dry-milled in a ball mill for 4 hours to ensure uniformity. The milled powder is then mixed with an organic binder system (total content not exceeding 3 wt.%) to form a slurry, wherein the organic component is a low-temperature decomposable binder and the balance is solvent.

[0109] The composite film prepared in Example 4 or Example 6 is covered on the upper and lower surfaces of the electronic device, and the low-temperature sintered ceramic raw material slurry is coated on the area to be sealed of the electronic device (including the periphery of the electronic device and between the composite films on the upper / lower surfaces) by screen printing technology. The thickness of the slurry body is controlled at 100-150 μm.

[0110] The sample was placed in a glove box with a high-purity nitrogen (99.999% purity) atmosphere. The sample was pre-dried on an 80°C hot plate for 30 minutes, and then treated in a vacuum environment at 150°C for 20 minutes to remove organic components. At this temperature, organic matter can slowly decompose and volatilize without causing damage to electronic devices. The ultrasonic packaging equipment was turned on, and the ultrasonic frequency and power were adjusted to allow the green body to be sintered and densified under ultrasonic vibration. By optimizing the ultrasonic parameters, the sintering temperature was maintained below 550°C to avoid high temperature damage to the polymer film. At the same time, ultrasonic vibration helps to improve the density inside the ceramic and improve the airtightness of the package.

[0111] The borate ceramics are sintered under ultrasonic action to form a dense edge sealing structure after sintering.

[0112] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0113] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A composite film containing a glass layer, characterized in that The invention comprises a base film and a glass layer. The glass layer is obtained by coating a glass melt on the surface of the base film. The base film comprises a polymer film or a surface-modified polymer film.

2. The composite membrane according to claim 1, characterized in that The surface-modified polymer film includes a polymer film and a modified layer, wherein the modified layer covers the surface of the polymer film, and the modified layer includes an inorganic layer, which includes at least one of a wetting layer having a surface energy close to that of a glass melt, an anti-corrosion layer having strong bond energy, an adhesive layer having a strong bonding effect with a substrate, and a thermal insulation layer.

3. The composite membrane according to claim 1, characterized in that The raw material of the glass melt includes fusible glass, and the maximum heat-resistant temperature of the base film is greater than or equal to the coating temperature of the glass melt.

4. The composite membrane according to claim 3, characterized in that The softening temperature of the fusible glass is ≤550°C, and the viscosity of the fusible glass corresponding to the softening temperature is 10 6.6 Pa s.

5. The method for preparing the composite membrane according to any one of claims 1 to 4, characterized in that: The following steps are involved: At a predetermined temperature, the base film is made straight in the width direction; the raw material of the glass melt is heated to above the de-interstitial temperature to remove the voids in the glass melt; at a coating temperature, the glass melt is coated on the surface of the base film; and heat treatment is performed to obtain a composite film containing a glass layer.

6. The preparation method according to claim 5, characterized in that Normal temperature≤the predetermined temperature≤process temperature, the process temperature is higher than the coating temperature, the coating temperature is the viscosity of the glass melt between 0.01 and 10 6.6 Pa s between any temperature corresponding to the temperature, the gap temperature is the viscosity of the glass melt is 10 5 Temperature at Pa s.

7. The preparation method according to any one of claims 5 to 6, characterized in that The coating method includes at least one of: engraving wheel coating, reverse coating, slot die coating, lip coating, blade coating, scraper coating, plate coating, liquid cavity blade coating, rod coating, air blade coating, and micro-dimpled coating; The heat treatment includes at least one of annealing, cooling, quenching, and laser irradiation treatment.

8. Use of the composite film according to any one of claims 1 to 4 in the preparation of a functional film, wherein the functional film is a high barrier film, an impact-resistant film and / or a hardened film, and the functional film is used for packaging or encapsulation.

9. A film for packaging or encapsulation, characterized in that The composite film comprises the composite film according to any one of claims 1 to 4.

10. A device packaging method, characterized in that: The method comprises the following steps: covering the film described in claim 9 on the upper surface and / or lower surface of the device, setting a packaging wall on the periphery of the device, connecting the packaging wall to the film on the upper surface and / or lower surface to form a sealed cavity, and the device is wrapped in the sealed cavity.

Images