A film material for laser transfer printing

Abstract

The application discloses a film material for laser transfer printing, and belongs to the technical field of laser transfer printing, which comprises a slurry transfer printing layer and a laser transmission layer which are bonded by an adhesive layer. The slurry transfer printing layer is provided as a multilayer structure including a surface layer, an intermediate layer and a bottom layer. The material composition, mixing ratio and thickness of each structure layer are further optimized, and the corresponding additives in the surface layer and the intermediate layer are added, so that the film material suitable for laser transfer printing is finally obtained. The film material for laser transfer printing has simple structure and reliable performance, can effectively meet the application in the laser transfer printing process, ensure the setting and use reliability of the film material in the pattern processing process, the slurry filling process and the slurry laser transfer printing process, improve the efficiency and precision of the slurry laser transfer printing, prolong the service life of the film material when used as a transfer film, and has good practical value.

Description

Technical Field

[0001] This invention belongs to the field of laser transfer technology, and specifically relates to a film material for laser transfer. Background Technology

[0002] In the process of photovoltaic cell processing, laser transfer printing, as a non-contact grid electrode processing method, can prepare grid electrodes with high aspect ratios and is increasingly used in the field of photovoltaic cell processing. With the development of photovoltaic cell technology and the increase in demand, higher requirements are placed on the efficiency and quality of laser transfer printing.

[0003] Existing laser transfer methods require the fabrication of a transparent carrier with a specified transfer pattern (grooves), and the filling of the grooves in the transparent carrier with photovoltaic paste using a squeegee. A specific wavelength laser is then used to scan the back of the groove area of ​​the transparent carrier, transferring the paste from the grooves to the silicon wafer beneath the transparent carrier.

[0004] In the aforementioned laser transfer process, the transparent carrier is typically a film, called a transfer film. Its quality and performance stability directly affect the laser transfer quality. Currently, flexible polymer materials of a single material are commonly used for laser transfer, such as PP (polypropylene), PE (polyethylene), and APET (amorphous polyethylene terephthalate). However, due to the relatively low tensile strength and elastic modulus of PP or PE, they are ill-suited to the tension required for pattern processing and the transfer process, making them prone to deformation. Typically, to resist deformation, the film thickness needs to be increased, which not only increases material costs but also negatively impacts subsequent use. Furthermore, the processing temperature during pattern processing often needs to be close to or higher than the material's melting point. PP, with its high melting point (160-170℃), increases processing energy consumption. Additionally, due to the thermal shrinkage of polymer materials, the pattern will distort (lines will bend) after hot pressing, especially with PE films, where excessive distortion can affect the alignment of the laser and the pattern during the transfer process.

[0005] Although amorphous PET has certain advantages in terms of mechanical strength, during the transfer process, the film material comes into contact with the transfer paste. Chemical reagents in the paste, such as butyl carbitol and terpineol, can cause stress cracking in amorphous PET.

[0006] In addition, the applicant found in the research that existing technologies have problems such as difficulty in demolding or even inability to demold when preparing transfer patterns; or, due to excessive demolding force, the processed structure cannot meet the requirements, affecting the process effect at the transfer end; or, after the transfer film is made, it still faces friction and extrusion during the process of filling the grooves of the transparent carrier with photovoltaic paste by a scraper, resulting in severe surface scratches and structural changes, affecting the final use effect. Summary of the Invention

[0007] In view of one or more of the above-mentioned defects or improvement needs of the prior art, the present invention provides a film material for laser transfer, which can effectively ensure the reliability and stability of the transfer film in the pattern processing process, the paste filling process and the laser transfer process, and reduce the material cost and energy consumption cost of laser transfer.

[0008] To achieve the above objectives, the present invention provides a film material for laser transfer printing, comprising a paste transfer layer and a laser transmission layer bonded together by an adhesive layer;

[0009] The paste transfer layer has a multi-layer structure, and the melting point of the part used to process the transfer pattern does not exceed 135°C. It includes a surface layer, an intermediate layer and a bottom layer that is bonded to the adhesive layer on one side, arranged sequentially from the outside to the inside. The sum of the thicknesses of the surface layer and the intermediate layer is not less than the groove depth of the transfer pattern.

[0010] The main components of the surface layer and the intermediate layer are a mixture of LDPE and HDPE or a mixture of LDPE, HDPE and EVA; and the main component of the bottom layer is LDPE or LLDPE.

[0011] The surface layer contains 1% to 2% of a release agent, 1% to 2% of a slip agent, and 0% to 1% of an opening agent, which are added by weight of the main components; the intermediate layer contains 1% to 2% of a release agent; and the bottom layer contains no additives.

[0012] As a further improvement of the present invention, the adhesive layer is a heat-resistant curing adhesive layer with a heat resistance temperature of not less than 120°C;

[0013] and / or

[0014] The adhesive layer is made of polyurethane adhesive or silicone adhesive;

[0015] and / or

[0016] The laser transmission layer is a support layer for the film material, which is made of BOPET or BOPA.

[0017] As a further improvement of the present invention, the release agent is a silicone masterbatch;

[0018] and / or

[0019] The slip agent is one or more of oleamide, erucamide, stearamide, and polyethylene wax.

[0020] As a further improvement of the present invention, the opening agent is one or more of talc, diatomaceous earth, dicalcium phosphate, and SiO2.

[0021] As a further improvement of the present invention, the thickness of the paste transfer layer is not less than 30 μm;

[0022] and / or

[0023] The thickness of the adhesive layer is no greater than 2 μm;

[0024] and / or

[0025] The thickness of the laser transmission layer is not less than 25 μm.

[0026] As a further improvement of the present invention, in the paste transfer layer, the thickness ratio of the surface layer, the intermediate layer and the bottom layer is (2~3):4:(2~3).

[0027] As a further improvement of the present invention, the groove is prepared by hot pressing process, and after hot pressing, the slip agent migrates to the groove wall and surface.

[0028] As a further improvement of the present invention, the main components of the surface layer and the intermediate layer are both a mixture of LDPE and HDPE, wherein the mass fraction of LDPE is 80~90wt% and the mass fraction of HDPE is 10~20wt%.

[0029] As a further improvement of the present invention, the main components of the surface layer and the intermediate layer are both mixtures of LDPE, HDPE and EVA, wherein the mass fraction of HDPE is 10~20wt% and the mass fraction of the remaining substances is 80~90wt%.

[0030] Of the remaining substances, the mass fraction of EVA is 10-60 wt%, and the mass fraction of LDPE is 20-80 wt%.

[0031] As a further improvement of the present invention, the melt index of LDPE is 2~4 g / 10 min, the melt index of EVA is 3~4 g / 10 min, and the melt index of HDPE is 2~3 g / 10 min.

[0032] The aforementioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0033] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include:

[0034] (1) The film material used for laser transfer in this invention includes a paste transfer layer and a laser transmission layer bonded together by an adhesive layer. By setting the paste transfer layer as a multi-layer structure including a surface layer, an intermediate layer and a bottom layer, and then optimizing the material composition, mixing ratio and thickness of each structural layer, and adding corresponding additives in the surface layer and intermediate layer, a film material suitable for laser transfer is finally obtained. This effectively meets the performance requirements of the film material when used as a transfer film, facilitates the demolding of the graphic mold during the transfer graphic processing, and ensures the anti-deformation ability of the film material during graphic processing, paste filling and paste transfer processes, and ensures the accuracy of the paste during laser transfer.

[0035] (2) The film material for laser transfer of the present invention, by optimizing the selection and type of adhesive layer, can match the performance of the paste transfer layer; at the same time, by optimizing the selection of laser transmission layer and matching its performance design, it can effectively provide support for the pattern processing of film material and its use as a transfer film, reduce the deformation of transfer film material in pattern processing, paste filling and paste transfer process, and improve the accuracy of laser transfer.

[0036] (3) The film material for laser transfer of the present invention, by optimizing the types of release agent, slip agent and opening agent, can further ensure the accuracy of film material preparation, improve the performance of film material in graphic processing and paste transfer, reduce the difficulty of film material demolding, improve the quality of graphic processing, and provide conditions for ensuring the accuracy of subsequent paste transfer.

[0037] (4) The membrane material for laser transfer of the present invention further specifies the proportion of the main components of the surface layer and the intermediate layer in the slurry transfer layer, so that the performance of the membrane material after preparation is more controllable, and further improves the adaptability of the membrane material in the application scenario of transfer membrane, and obtains a membrane material with stable structure and excellent performance.

[0038] (5) The film material used for laser transfer in this invention has a simple structure and reliable performance. It can effectively meet the application requirements in the laser transfer process, ensure the reliability of the film material in the graphic processing process, the slurry filling process and the slurry laser transfer process, improve the efficiency and accuracy of slurry laser transfer, and has good practical value. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of the film material used for laser transfer in an embodiment of the present invention;

[0041] Figure 2 This is a cross-sectional schematic diagram of the film material used for laser transfer printing in an embodiment of the present invention after pattern processing;

[0042] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically:

[0043] 1. Paste transfer layer; 101. Surface layer; 102. Intermediate layer; 103. Bottom layer; 2. Adhesive layer; 3. Laser transmission layer; 4. Grooves. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0045] In the description of this invention, it should be understood that, unless otherwise expressly specified and limited, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0047] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0048] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0049] Example:

[0050] Please see Figure 1 In a preferred embodiment of the present invention, the film material for laser transfer has a multi-layer structure, comprising a paste transfer layer 1 and a laser transmission layer 3 bonded together by an adhesive layer 2. The surface of the paste transfer layer 1 facing away from the laser transmission layer 3 is used for processing the transfer pattern, and grooves 4 for filling the transfer paste can be formed after pattern processing. The laser transmission layer 3 is located on the side of the film material facing away from the transfer pattern; as the substrate of the film material, it plays a role in maintaining the shape of the film structure and supporting the film material to complete the laser transfer process.

[0051] Specifically, for the membrane material in the preferred embodiment, it needs to be laser-transfer printed. To ensure the reliability of the laser transfer, the membrane material needs to have a high transmittance to a specific wavelength laser (processing laser), which is preferably not less than 90%.

[0052] Meanwhile, for the paste transfer layer 1 in the preferred embodiment, it needs to be processed to form a transfer pattern. That is, transfer grooves 4 with a certain depth and specific pattern are processed on the surface of the paste transfer layer 1 according to the transfer requirements. These grooves are then used to fill the transfer paste into the transfer paste. Figure 2 As shown, it is understandable. Figure 2 The diagram illustrates a rectangular groove, but in practical applications, the groove can be an inverted trapezoidal groove or a triangular groove, etc. Those skilled in the art will understand that when it is an inverted trapezoidal or triangular groove, the groove width refers to the width of the opening.

[0053] It is understood that the film material used for laser transfer in the preferred embodiment of the present invention, as an application of laser transfer, requires not only good laser transmittance, but also the following properties:

[0054] On the one hand, it needs to have good processing performance to hot-press the grooves 4 of the transfer pattern; on the other hand, it needs to have sufficient flexibility and strength to allow the photovoltaic paste to be scraped into the grooves 4 using a squeegee without causing excessive deformation or damage to the film material. In addition, it also needs to have good resistance to paste corrosion and polarity so that the transfer layer (including the grooves) is not damaged by the paste, and that the photovoltaic paste can fill the grooves 4 well, so as to obtain transfer grid electrodes that are closer to the groove design dimensions.

[0055] After research, the applicant sets the paste transfer layer 1 as a multi-layer structure, including at least a surface layer 101, an intermediate layer 102 and a bottom layer 103 arranged sequentially from the outside to the inside along the thickness direction; wherein, the surface layer 101 is located on the side of the paste transfer layer 1 away from the adhesive layer 2, and the bottom layer 103 is located on the side close to the adhesive layer 2, which is used to fix and bond the film material to the laser transmission layer 3 through the adhesive layer 2 to form an integral structure.

[0056] In actual setup, the main component of the slurry transfer layer 1 in the preferred embodiment is polyolefin, and its processing temperature is low when processing the groove 4 pattern, and it has good resistance to chemical reagents, which can ensure the stability and reliability of the film material performance during the interaction with the slurry.

[0057] More specifically, for the slurry transfer layer 1 in the preferred embodiment, the main components of its surface layer 101 and intermediate layer 102 are preferably the same, and more preferably both are a mixture of LDPE (low-density polyethylene) and HDPE (high-density polyethylene), or both are a mixture of LDPE, HDPE and EVA (ethylene-vinyl acetate copolymer). Meanwhile, in the preferred embodiment, the main component of the bottom layer 103 in the slurry transfer layer 1 is LDPE or LLDPE (linear low-density polyethylene).

[0058] In the mixture of LDPE and HDPE, the mass fraction of LDPE is 80~90wt%, with any range or point value in between, and the mass fraction of HDPE is 10~20wt%, with any range or point value in between.

[0059] In the mixture of LDPE, HDPE and EVA, the mass fraction of HDPE is 10~20wt%, with any value or point value in between, and the mass fraction of the other substances is 80~90wt%, with any value or point value in between. For example, the mass fraction of EVA is 10~60wt%, with any value or point value in between, and the mass fraction of LDPE is 20~80wt%, with any value or point value in between.

[0060] More specifically, the melt index of LDPE is 2~4 g / 10 min, any range or point value in between; the melt index of EVA is 3~4 g / 10 min, any range or point value in between; and the melt index of HDPE is 2~3 g / 10 min, any range or point value in between.

[0061] Since the processing temperature of EVA and LDPE can be controlled below 115°C, and that of EVA can even be controlled below 105°C, the material selection of the surface layer 101 and intermediate layer 102 of the aforementioned paste transfer layer 1 effectively reduces the difficulty of processing the film material for the (groove 4) pattern, and also reduces energy consumption, thereby effectively reducing the cost of transfer processing. In a preferred embodiment, the melting point of the area used for processing the transfer pattern is preferably not more than 135°C, and more preferably not more than 125°C.

[0062] Meanwhile, HDPE has a higher hardness than LDPE (LDPE Shore hardness 40~50D, LDPE Shore hardness 65~70D). Therefore, the hardness of the membrane material after adding HDPE to LDPE is higher than that of LDPE alone, falling between that of LDPE and HDPE.

[0063] However, the melting temperature of LDPE is below 115℃, or even below 110℃; while the melting temperature of HDPE is generally above 130℃. When HDPE is mixed into LDPE to form a blend, there are two situations regarding its melting temperature: (1) The two are completely compatible, and the differential thermal analysis curve of the blend shows only one melting peak, with the melting point peak between LDPE and HDPE; (2) The two are partially compatible, and the differential thermal analysis curve of the blend shows two melting peaks, one appearing at a point where the melting peak of LDPE is shifted towards a higher temperature, and the other appearing at a point where the melting peak of HDPE is shifted towards a lower temperature.

[0064] In other words, the addition of HDPE results in a higher melting point for the blend compared to LDPE. When the HDPE content is controlled at a low level, such as below 20%, the blend is often only partially compatible. In this case, only a 5-10°C increase in temperature is needed compared to the original LDPE pattern processing temperature for pattern processing. Since the blend is not completely melted when the temperature is increased by 5-10°C (compared to single LDPE pattern processing), the surface adhesion between the mold and the film material is reduced, thereby lowering the demolding force. This avoids the problem of poor laser transfer accuracy caused by a large demolding force affecting the processing accuracy of groove 4.

[0065] In another preferred embodiment, the slurry transfer layer 1 is a blend of LDPE, HDPE, and EVA. Since EVA has a low melting point, typically below 100°C, the pattern processing temperature of its blend with LDPE and HDPE is lower than that of the aforementioned LDPE and HDPE blend. Furthermore, the addition of EVA can improve the surface polarity of the film material, allowing the photovoltaic slurry to better contact and fill the trenches 4.

[0066] Furthermore, in addition to the aforementioned main components, a certain percentage of additives is added to the slurry transfer layer 1. In a preferred embodiment, the surface layer 101 contains 1% to 2% of a release agent (any range or point value within which), 1% to 2% of a slip agent (any range or point value within which), and 0% to 1% of an opening agent (any range or point value within which); the intermediate layer 102 contains 1% to 2% of a release agent (any range or point value within which); correspondingly, no additives are added to the bottom layer 103.

[0067] More specifically, in the preferred embodiments, the slip agent is one or more of oleamide, erucamide, stearamide, polyethylene wax, and fluoropolymer; the release agent is silicone masterbatch; and the opening agent is preferably one or more of talc, diatomaceous earth, dicalcium phosphate, and SiO2.

[0068] Since grooves 4 need to be processed in the surface layer 101 when the film material is patterned, the addition of a release agent to the surface layer 101 can improve the processing performance of plastic particles when they are processed into film, and lubricate the film surface and the mold surface, thereby reducing the release force, ensuring good release effect when the grooves 4 are processed and ensuring the processing accuracy of the grooves 4, thus ensuring the processing accuracy during laser transfer.

[0069] Meanwhile, the slip agent functions similarly to a release agent, lubricating the film and mold surfaces to reduce release force. It also lowers the film surface friction coefficient, facilitating film movement during processing. Furthermore, because the slip agent reduces surface friction, it helps minimize scratches on the film surface during the sizing process, preventing damage to the groove edges and thus improving transfer quality and extending the film's lifespan.

[0070] However, the reason for adding the slip agent only to the surface layer 101 is to reduce its migration to the adhesive layer 2 during the film processing, and to prevent the slip agent from migrating to the adhesive layer 2 and affecting the bonding strength between the bottom layer 103 and the laser transmission layer 3.

[0071] In addition, the opening agent is mainly used to prevent the films from sticking together, so as to avoid affecting the processing of the film material itself and the winding and unwinding process of the groove 4 processing.

[0072] More specifically, the thickness of the paste transfer layer 1 in actual setup is preferably not less than 30μm, and the thickness ratio of the surface layer 101, the intermediate layer 102, and the bottom layer 103 is preferably (2~3):4:(2~3), for example 3:4:3 or 1:2:1.

[0073] Through the composition and proportion of the main components of the surface layer 101, intermediate layer 102, and bottom layer 103 in the above technical solution, as well as the setting of additives, the surface layer 101 has good processability, is easy to demold, and is easy to prepare the groove 4 pattern. It has a certain strength, allowing the squeegee to easily scrape the paste into it, forming good filling. It also has good polarity and resistance to paste corrosion, so that the photovoltaic paste can not only fill the groove 4 well, but also detach from the groove 4 better during laser irradiation to achieve transfer. At the same time, the main components of the intermediate layer 102 are the same as those of the surface layer 101, with slight differences in additives. This can prevent the slip agent from migrating to the adhesive layer 2 and affecting the peel strength of the film material, thereby ensuring that the bottom layer 103 can achieve a good bonding effect with the paste transfer layer 1 through the adhesive layer 2. In addition, the bottom layer 103 is a single resin component with good laser transmittance, which can achieve good bonding with the laser transmission layer 3 through the adhesive layer 2.

[0074] More specifically, in a preferred embodiment, grooves 4 of the transfer pattern need to be formed on the slurry transfer layer 1. The grooves 4 are prepared by hot pressing, and the pressing temperature is further preferably 115°C. After hot pressing, the slip agent migrates to the groove wall and surface to form an accumulation, which can reduce the coefficient of friction of the film surface and reduce damage to the film by the doctor blade. At the same time, it can also make the slurry fill the groove more densely.

[0075] In specific settings, the thickness of the paste transfer layer 1 is preferably 30~45µm, and the thickness ratio of the surface layer 101, intermediate layer 102, and bottom layer 103 is preferably 3:4:3 or 1:2:1. Simultaneously, in actual settings, the depth of the grooves 4 will not reach the bottom layer 103; that is, the depth of the grooves 4 does not exceed the intermediate layer 102, meaning the sum of the thicknesses of the surface layer 101 and the intermediate layer 102 is not less than the depth of the grooves 4 in the transfer pattern. For example… Figure 2 As shown in the image.

[0076] In a preferred embodiment, the bottom of the trench 4 is at least 2µm away from the bottom layer 103, meaning the sum of the thicknesses of the surface layer 101 and the intermediate layer 102 is at least 2µm greater than the depth of the trench 4. Meanwhile, the spacing between adjacent trenches 4 is preferably 0.1mm to 1.2mm.

[0077] Furthermore, the thickness of the adhesive layer 2 is preferably no more than 2 μm, and it is even more preferably a heat-resistant curing adhesive layer with a heat resistance temperature of not less than 120°C, to ensure that the adhesive layer 2 does not flow, decompose, or deform significantly when the paste transfer layer 1 is processed into a graphic.

[0078] In actual preparation, the adhesive layer 2 selected in the preferred embodiment can preferably be made of either polyurethane adhesive or silicone adhesive.

[0079] Furthermore, in the actual preparation of the laser transmission layer 3, in addition to ensuring its light transmittance, it is also necessary to ensure its good mechanical properties and heat resistance. In the preferred embodiment, the laser transmission layer 3 serves as a support layer for the film material, undertaking the functions of maintaining structural stability during pattern processing of the paste transfer layer 1 and subsequent transfer operations, reducing structural deformation during film material processing and operation, and ensuring the processing accuracy of the grooves 4, thereby ensuring the accuracy of laser transfer.

[0080] In a preferred embodiment, the laser transmission layer 3 can be made of BOPET (biaxially oriented polyethylene terephthalate film) or BOPA (biaxially oriented nylon film). Taking BOPET as an example, it has excellent mechanical properties (stiffness, tensile strength, tensile modulus, etc.), and a relatively thin thickness can provide good tensile resistance. At the same time, due to the low thermal shrinkage rate of BOPET, it can resist the structural bending caused by the shrinkage of the paste transfer layer 1 during pattern processing, so that the bending of the pattern structure is controlled within a small range.

[0081] For example, for a single LDPE film, the structural bending after patterning can reach 50~100μm; while for a multilayer composite film of LDPE and BOPET, the structural bending after patterning can be controlled within 5~20μm, which is beneficial for the precise alignment of the laser and the filling paste during the transfer process.

[0082] More preferably, in actual preparation, the thickness of the laser transmission layer 3 is preferably not less than 25 μm, and more preferably 36 μm or 50 μm.

[0083] Meanwhile, in the preferred embodiment, the tensile strength of the laser transmission layer 3 is not less than 150 MPa, the heat resistance temperature is not less than 180°C, and the thermal shrinkage rate under 150°C conditions for 30 minutes is not greater than 1%.

[0084] Through the aforementioned settings, a membrane material with good structural stability and structural performance that meets the requirements of laser transfer film can be obtained. This fully ensures the convenience of demolding when the membrane material is patterned, and ensures the deformation resistance of the membrane material during patterning, slurry filling and transfer processes. It also reduces the power consumption of the membrane material and improves the accuracy of slurry laser transfer.

[0085] The aforementioned membrane material will be further described below through several specific preferred embodiments.

[0086] Example 1:

[0087] In this embodiment, the main components of the surface layer 101 and the intermediate layer 102 of the slurry transfer layer 1 are both blends of LDPE and HDPE.

[0088] In the surface layer 101, the melt index of LDPE is 2 g / 10 min and the mass ratio is 90 wt%; the mass ratio of HDPE is 10 wt% and the melt index of HDPE is 2 g / 10 min.

[0089] Meanwhile, 2 wt% of silicone masterbatch, which accounts for the main component, is added to the surface layer 101 as a release agent, and 1 wt% of erucamide, which accounts for the main component, is added as a slip agent.

[0090] Secondly, compared with the surface layer 101, the main components of the intermediate layer 102 are the same as those of the surface layer 101, and the proportion and type of release agent are also the same. The only difference is that no slip agent is added.

[0091] Furthermore, the bottom layer 103 of the paste transfer layer 1 is made of LLDPE with a melt index of 2 g / 10 min, and no additives are added to the bottom layer 103.

[0092] More specifically, in this embodiment, the thicknesses of the aforementioned surface layer 101, intermediate layer 102, and bottom layer 103 are 12 μm, 16 μm, and 12 μm, respectively.

[0093] Meanwhile, when patterning is performed on the membrane material in this embodiment, the groove depth is 20μm, the groove width-to-depth ratio is 0.8, and the spacing between adjacent grooves is 1.2mm.

[0094] Furthermore, the adhesive layer 2 of the membrane material is a two-component polyurethane adhesive with a thickness of less than 2 μm. Correspondingly, the laser transmission layer 3 is made of BOPET material with a thickness of 50 μm.

[0095] Example 2:

[0096] In this embodiment, the main components of the surface layer 101 and the intermediate layer 102 of the slurry transfer layer 1 are both blends of LDPE and HDPE.

[0097] In the surface layer 101, the melt index of LDPE is 2 g / 10 min and the mass ratio is 80 wt%; the mass ratio of HDPE is 20 wt% and the melt index of HDPE is 2 g / 10 min.

[0098] Meanwhile, 1 wt% of silicone masterbatch, which accounts for 1 wt% of the main components, is added to the surface layer 101 as a release agent, and 1 wt% of erucamide, which accounts for 1 wt% of the main components, is added as a slip agent.

[0099] Secondly, compared with the surface layer 101, the main components of the intermediate layer 102 are the same as those of the surface layer 101, and the proportion and type of release agent are also the same. The only difference is that no slip agent is added.

[0100] Furthermore, the bottom layer 103 of the paste transfer layer 1 is made of LLDPE with a melt index of 2 g / 10 min, and no additives are added to the bottom layer 103.

[0101] More specifically, in this embodiment, the thicknesses of the aforementioned surface layer 101, intermediate layer 102, and bottom layer 103 are 12 μm, 16 μm, and 12 μm, respectively.

[0102] Meanwhile, when patterning is performed on the membrane material in this embodiment, the groove depth is 20μm, the groove width-to-depth ratio is 0.8, and the spacing between adjacent grooves is 1.2mm.

[0103] Furthermore, the adhesive layer 2 of the membrane material is a two-component polyurethane adhesive with a thickness of less than 2 μm. Correspondingly, the laser transmission layer 3 is made of BOPET material with a thickness of 50 μm.

[0104] Example 3:

[0105] In this embodiment, the main components of the surface layer 101 and the intermediate layer 102 of the slurry transfer layer 1 are both blends of LDPE and HDPE.

[0106] In the surface layer 101, the melt index of LDPE is 2 g / 10 min and the mass ratio is 85 wt%; the mass ratio of HDPE is 15 wt% and the melt index of HDPE is 2 g / 10 min.

[0107] Meanwhile, 1.5 wt% of silicone masterbatch, which accounts for the main component, is added to the surface layer 101 as a release agent, and 1 wt% of erucamide, which accounts for the main component, is added as a slip agent.

[0108] Secondly, compared with the surface layer 101, the main components of the intermediate layer 102 are the same as those of the surface layer 101, and the proportion and type of release agent are also the same. The only difference is that no slip agent is added.

[0109] Furthermore, the bottom layer 103 of the paste transfer layer 1 is made of LLDPE with a melt index of 2 g / 10 min, and no additives are added to the bottom layer 103.

[0110] More specifically, in this embodiment, the thicknesses of the aforementioned surface layer 101, intermediate layer 102, and bottom layer 103 are 12 μm, 16 μm, and 12 μm, respectively.

[0111] Meanwhile, when patterning is performed on the membrane material in this embodiment, the groove depth is 20μm, the groove width-to-depth ratio is 0.8, and the spacing between adjacent grooves is 1.2mm.

[0112] Furthermore, the adhesive layer 2 of the membrane material is a two-component polyurethane adhesive with a thickness of less than 2 μm. Correspondingly, the laser transmission layer 3 is made of BOPET material with a thickness of 50 μm.

[0113] Example 4:

[0114] In this embodiment, the main components of the surface layer 101 and the intermediate layer 102 of the slurry transfer layer 1 are both blends of LDPE and HDPE.

[0115] Among them, the melt index of LDPE in the surface layer 101 is 4 g / 10 min, and the mass ratio is 80 wt%; the mass ratio of HDPE is 20 wt%, and the melt index of HDPE is 3 g / 10 min.

[0116] Meanwhile, 2 wt% of silicone masterbatch as a release agent, 2 wt% of erucamide as a slip agent, and 1 wt% of SiO2 as an opening agent are added to the surface layer 101.

[0117] Secondly, compared with the surface layer 101, the main components of the intermediate layer 102 are the same as those of the surface layer 101, and the proportion and type of release agent are also the same. The only difference is that no slip agent and opening agent are added.

[0118] Furthermore, the bottom layer 103 of the paste transfer layer 1 is made of LLDPE with a melt index of 2 g / 10 min, and no additives are added to the bottom layer 103.

[0119] More specifically, in this embodiment, the thicknesses of the aforementioned surface layer 101, intermediate layer 102, and bottom layer 103 are 12 μm, 16 μm, and 12 μm, respectively.

[0120] Meanwhile, when patterning is performed on the membrane material in this embodiment, the groove depth is 20μm, the groove width-to-depth ratio is 0.8, and the spacing between adjacent grooves is 1.2mm.

[0121] Furthermore, the adhesive layer 2 of the membrane material is a two-component polyurethane adhesive with a thickness of less than 2 μm. Correspondingly, the laser transmission layer 3 is made of BOPET material with a thickness of 50 μm.

[0122] Example 5:

[0123] In this embodiment, the main components of the surface layer 101 and the intermediate layer 102 of the slurry transfer layer 1 are blends of LDPE, HDPE and EVA.

[0124] The EVA has a melt index of 3 g / 10 min, and the VA (vinyl acetate) content in the EVA is no more than 12%. Correspondingly, the melt index of LDPE is 2 g / 10 min, and the melt index of HDPE is 2 g / 10 min.

[0125] More specifically, in the surface layer 101, the mass ratio of HDPE is 10 wt%, the mass ratio of LDPE is 80 wt%, and the mass ratio of EVA is 10 wt%.

[0126] Meanwhile, 2 wt% of silicone masterbatch, which accounts for the main component, is added to the surface layer 101 as a release agent, and 1 wt% of erucamide, which accounts for the main component, is added as a slip agent.

[0127] Compared to the surface layer 101, no slip agent is added to the intermediate layer 102 in this embodiment, and the other components are arranged in the same way as the surface layer 101.

[0128] Furthermore, the bottom layer 103 of the paste transfer layer 1 is made of LLDPE with a melt index of 2 g / 10 min, and no other additives are added to the bottom layer 103.

[0129] More specifically, in this embodiment, the thicknesses of the aforementioned surface layer 101, intermediate layer 102, and bottom layer 103 are 12 μm, 16 μm, and 12 μm, respectively.

[0130] Meanwhile, when patterning is performed on the membrane material in this embodiment, the groove depth is 20μm, the groove width-to-depth ratio is 1, and the spacing between adjacent grooves is 1.2mm.

[0131] Furthermore, the adhesive layer 2 of the membrane material is a two-component polyurethane adhesive with a thickness of less than 2 μm. Correspondingly, the laser transmission layer 3 is made of BOPET material with a thickness of 50 μm.

[0132] Example 6:

[0133] In this embodiment, the main components of the surface layer 101 and the intermediate layer 102 of the slurry transfer layer 1 are blends of LDPE, HDPE and EVA.

[0134] The EVA has a melt index of 3 g / 10 min, and the VA (vinyl acetate) content in the EVA is no more than 12%. Correspondingly, the melt index of LDPE is 2 g / 10 min, and the melt index of HDPE is 2 g / 10 min.

[0135] More specifically, in the surface layer 101, the mass ratio of HDPE is 20 wt%, the mass ratio of LDPE is 40 wt%, and the mass ratio of EVA is 40 wt%.

[0136] Meanwhile, 2 wt% of silicone masterbatch, which accounts for the main component, is added to the surface layer 101 as a release agent, and 2 wt% of erucamide, which accounts for the main component, is added as a slip agent.

[0137] Compared to the surface layer 101, no slip agent is added to the intermediate layer 102 in this embodiment, and the other components are arranged in the same way as the surface layer 101.

[0138] Furthermore, the bottom layer 103 of the paste transfer layer 1 is made of LLDPE with a melt index of 2 g / 10 min, and no other additives are added to the bottom layer 103.

[0139] More specifically, in this embodiment, the thicknesses of the aforementioned surface layer 101, intermediate layer 102, and bottom layer 103 are 12 μm, 16 μm, and 12 μm, respectively.

[0140] Meanwhile, when patterning is performed on the membrane material in this embodiment, the groove depth is 20μm, the groove width-to-depth ratio is 1, and the spacing between adjacent grooves is 1.2mm.

[0141] Furthermore, the adhesive layer 2 of the membrane material is a two-component polyurethane adhesive with a thickness of less than 2 μm. Correspondingly, the laser transmission layer 3 is made of BOPET material with a thickness of 50 μm.

[0142] Example 7:

[0143] In this embodiment, the main components of the surface layer 101 and the intermediate layer 102 of the slurry transfer layer 1 are blends of LDPE, HDPE and EVA.

[0144] The EVA has a melt index of 3 g / 10 min, and the VA (vinyl acetate) content in the EVA is no more than 12%. Correspondingly, the melt index of LDPE is 2 g / 10 min, and the melt index of HDPE is 2 g / 10 min.

[0145] More specifically, in the surface layer 101, the mass ratio of HDPE is 20 wt%, the mass ratio of LDPE is 20 wt%, and the mass ratio of EVA is 60 wt%.

[0146] Meanwhile, 2 wt% of silicone masterbatch, which accounts for the main component, is added to the surface layer 101 as a release agent, and 2 wt% of erucamide, which accounts for the main component, is added as a slip agent.

[0147] Compared to the surface layer 101, no slip agent is added to the intermediate layer 102 in this embodiment, and the other components are arranged in the same way as the surface layer 101.

[0148] Furthermore, the bottom layer 103 of the paste transfer layer 1 is made of LLDPE with a melt index of 2 g / 10 min, and no other additives are added to the bottom layer 103.

[0149] More specifically, in this embodiment, the thicknesses of the aforementioned surface layer 101, intermediate layer 102, and bottom layer 103 are 12 μm, 16 μm, and 12 μm, respectively.

[0150] Meanwhile, when patterning is performed on the membrane material in this embodiment, the groove depth is 20μm, the groove width-to-depth ratio is 1, and the spacing between adjacent grooves is 1.2mm.

[0151] Furthermore, the adhesive layer 2 of the membrane material is a two-component polyurethane adhesive with a thickness of less than 2 μm. Correspondingly, the laser transmission layer 3 is made of BOPET material with a thickness of 50 μm.

[0152] Example 8:

[0153] In this embodiment, the main components of the surface layer 101 and the intermediate layer 102 of the slurry transfer layer 1 are blends of LDPE, HDPE and EVA.

[0154] The EVA has a melt index of 3 g / 10 min, and the VA (vinyl acetate) content in the EVA is no more than 12%. Correspondingly, the melt index of LDPE is 4 g / 10 min, and the melt index of HDPE is 3 g / 10 min.

[0155] More specifically, in the surface layer 101, the mass ratio of HDPE is 10 wt%, the mass ratio of LDPE is 80 wt%, and the mass ratio of EVA is 10 wt%.

[0156] Meanwhile, 1 wt% of silicone masterbatch as a release agent, 2 wt% of erucamide as a slip agent, and 1 wt% of SiO2 as an opening agent are added to the surface layer 101.

[0157] Compared to the surface layer 101, the intermediate layer 102 of this embodiment does not contain any slip agent or opening agent, and the other components are arranged in the same way as the surface layer 101.

[0158] Furthermore, the bottom layer 103 of the paste transfer layer 1 is made of LLDPE with a melt index of 2 g / 10 min, and no other additives are added to the bottom layer 103.

[0159] More specifically, in this embodiment, the thicknesses of the aforementioned surface layer 101, intermediate layer 102, and bottom layer 103 are 12 μm, 16 μm, and 12 μm, respectively.

[0160] Meanwhile, when patterning is performed on the membrane material in this embodiment, the groove depth is 20μm, the groove width-to-depth ratio is 1, and the spacing between adjacent grooves is 1.2mm.

[0161] Furthermore, the adhesive layer 2 of the membrane material is a two-component polyurethane adhesive with a thickness of less than 2 μm. Correspondingly, the laser transmission layer 3 is made of BOPET material with a thickness of 50 μm.

[0162] Example 9:

[0163] In this embodiment, the main components of the surface layer 101 and the intermediate layer 102 of the slurry transfer layer 1 are blends of LDPE, HDPE and EVA.

[0164] The EVA has a melt index of 4 g / 10 min, and the VA (vinyl acetate) content in the EVA is no more than 12%. Correspondingly, the melt index of LDPE is 2 g / 10 min, and the melt index of HDPE is 2 g / 10 min.

[0165] More specifically, in the surface layer 101, the mass ratio of HDPE is 10 wt%, the mass ratio of LDPE is 80 wt%, and the mass ratio of EVA is 10 wt%.

[0166] Meanwhile, 2 wt% of silicone masterbatch, which accounts for the main component, is added to the surface layer 101 as a release agent, and 2 wt% of erucamide, which accounts for the main component, is added as a slip agent.

[0167] Compared to the surface layer 101, no slip agent is added to the intermediate layer 102 in this embodiment, and the other components are arranged in the same way as the surface layer 101.

[0168] Furthermore, the bottom layer 103 of the paste transfer layer 1 is made of LLDPE with a melt index of 2 g / 10 min, and no other additives are added to the bottom layer 103.

[0169] More specifically, in this embodiment, the thicknesses of the aforementioned surface layer 101, intermediate layer 102, and bottom layer 103 are 12 μm, 16 μm, and 12 μm, respectively.

[0170] Meanwhile, when patterning is performed on the membrane material in this embodiment, the groove depth is 20μm, the groove width-to-depth ratio is 1, and the spacing between adjacent grooves is 1.2mm.

[0171] Furthermore, the adhesive layer 2 of the membrane material is a two-component polyurethane adhesive with a thickness of less than 2 μm. Correspondingly, the laser transmission layer 3 is made of BOPET material with a thickness of 50 μm.

[0172] Comparative Example 1:

[0173] In this embodiment, the adhesive layer 2 and the laser transmission layer 3 are arranged in the same way as in embodiment 1. The difference is that the slurry transfer layer has only one layer of LDPE with a melt index of 2g / 10min, and the thickness is the same as the overall thickness of the slurry transfer layer 1 in embodiment 1.

[0174] Comparative Example 2:

[0175] In this embodiment, the adhesive layer 2 and the laser transmission layer 3 are configured in the same way as in embodiment 1, the only difference being that no additives are added to the surface, intermediate and bottom layers of the paste transfer layer 1.

[0176] Comparative Example 3:

[0177] In this embodiment, the adhesive layer 2 and the laser transmission layer 3 are configured in the same way as in embodiment 1, except that 1 wt% erucamide is added as a slip agent in the middle layer of the paste transfer layer 1.

[0178] Comparative Example 4:

[0179] In this embodiment, the adhesive layer 2 and the laser transmission layer 3 are configured in the same way as in embodiment 7, except that 2 wt% erucamide is added as a slip agent in the middle layer of the paste transfer layer 1.

[0180] By performing pattern processing on the slurry transfer layer 1 and laser transfer operation on the film materials obtained in Examples 1-9 and Comparative Examples 1-4 respectively, the comparison results shown in Table 1 below were obtained.

[0181] Table 1. Comparison of the performance of membrane materials in Examples 1-9 and Comparative Examples 1-4

[0182]

[0183] As shown in Table 1, the membrane materials prepared according to Examples 1-9 above, due to the selection of polyolefin materials and the design of component ratios, can reliably control the pattern processing temperature below 125°C, resulting in lower pattern processing difficulty and energy consumption. Furthermore, due to the layered configuration of release agents, slip agents, and other additives, the release force during pattern processing is controlled within a low range. After microstructure formation, no significant shape or size changes occur due to the pulling effect of the release force, and the membrane does not delaminate. Additionally, due to the selection of heat-resistant and low-shrinkage BOPET, the overall structural deformation after pattern processing is controlled within a low range (all less than 25 μm), indicating good overall performance in pattern processing.

[0184] In contrast, for Comparative Examples 1 to 4, which did not adopt the technical solutions designed in the aforementioned preferred embodiments, the prepared film materials are difficult to use as transfer films for laser transfer printing. They have defects such as difficulty in demolding during pattern processing and / or film material delamination, and cannot meet the actual transfer printing process requirements.

[0185] Furthermore, a more detailed comparison reveals that in Examples 1-4, the addition of an appropriate proportion of HDPE improves the surface hardness of the film, reducing surface scratches caused by the squeegee when filling the slurry at the transfer end. In Examples 5-9, HDPE achieves the same effect, and the addition of an appropriate proportion of EVA results in better filling density of the slurry in the pattern when used at the transfer end, allowing for a slightly higher height of the transfer grid electrode. However, when the amount of EVA added is large, the overall surface hardness of the film decreases, and the pattern deforms downwards more after the squeegee is pressed down. The slurry is filled at this point, and after the squeegee passes over, the deformation recovers, resulting in a larger unfilled space on the shallow surface after the pattern is filled. The actual width after slurry filling decreases (the microstructure is generally set as an inverted trapezoid), thus allowing for narrower grid electrodes.

[0186] The film material used for laser transfer in this invention has a simple structure and reliable performance. It can effectively meet the application requirements in the laser transfer process, ensure the reliability of the film material in the graphic processing, slurry filling and slurry laser transfer processes, improve the efficiency and accuracy of slurry laser transfer, and extend the life of the film material when used as a transfer film. It has good practical value.

[0187] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A film material for laser transfer printing, characterized in that, It includes a paste transfer layer and a laser transmission layer bonded together by an adhesive layer; The paste transfer layer has a multi-layer structure, and the melting point of the part used to process the transfer pattern does not exceed 135°C. It includes a surface layer, an intermediate layer and a bottom layer that is bonded to the adhesive layer on one side, arranged sequentially from the outside to the inside. The sum of the thicknesses of the surface layer and the intermediate layer is not less than the groove depth of the transfer pattern. The main components of the surface layer and the intermediate layer are a mixture of LDPE and HDPE or a mixture of LDPE, HDPE and EVA; and the main component of the bottom layer is LDPE or LLDPE. The surface layer contains 1% to 2% of a release agent, 1% to 2% of a slip agent, and 0% to 1% of an opening agent, accounting for 1% to 2% of the main components by mass; and the intermediate layer contains 1% to 2% of a release agent. Furthermore, no slip agent was added to the intermediate layer, and no additives were added to the bottom layer.

2. The film material for laser transfer printing according to claim 1, characterized in that, The adhesive layer is a heat-resistant curing adhesive layer with a heat resistance temperature of not less than 120°C; and / or The adhesive layer is made of polyurethane adhesive or silicone adhesive; and / or The laser transmission layer is a support layer for the film material, which is made of BOPET or BOPA.

3. The film material for laser transfer printing according to claim 1 or 2, characterized in that, The release agent is silicone masterbatch; and / or The slip agent is one or more of oleamide, erucamide, stearamide, and polyethylene wax.

4. The film material for laser transfer printing according to claim 3, characterized in that, The opening agent is one or more of talc, diatomaceous earth, dicalcium phosphate, and SiO2.

5. The film material for laser transfer printing according to claim 1, 2, or 4, characterized in that, The thickness of the paste transfer layer is not less than 30 μm; and / or The thickness of the adhesive layer is no greater than 2 μm; and / or The thickness of the laser transmission layer is not less than 25 μm.

6. The film material for laser transfer printing according to claim 1, 2, or 4, characterized in that, In the paste transfer layer, the thickness ratio of the surface layer, the intermediate layer and the bottom layer is (2~3):4:(2~3).

7. The film material for laser transfer printing according to claim 6, characterized in that, The groove is prepared by hot pressing, and after hot pressing, the slip agent migrates to the groove wall and surface.

8. The film material for laser transfer printing according to claim 1, 2, 4, or 7, characterized in that, The main components of the surface layer and the intermediate layer are both mixtures of LDPE and HDPE, wherein the mass fraction of LDPE is 80~90wt% and the mass fraction of HDPE is 10~20wt%.

9. The film material for laser transfer printing according to claim 1, 2, 4, or 7, characterized in that, The main components of the surface layer and the intermediate layer are a mixture of LDPE, HDPE and EVA, wherein the mass fraction of HDPE is 10-20 wt% and the mass fraction of the remaining substances is 80-90 wt%. Of the remaining substances, the mass fraction of EVA is 10-60 wt%, and the mass fraction of LDPE is 20-80 wt%.

10. The film material for laser transfer printing according to claim 1, 2, 4, or 7, characterized in that, The melt index of LDPE is 2~4 g / 10 min, the melt index of EVA is 3~4 g / 10 min, and the melt index of HDPE is 2~3 g / 10 min.

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