UV curing method and curing device for glue

Abstract

The invention relates to a UV curing method and device for glue. The UV curing method of the glue comprises the following steps: shielding an ultraviolet lamp by using a UV blocking glue film which can block ultraviolet light of a first wave band and allows ultraviolet light of a second wave band to penetrate through; and irradiating the glue by using the ultraviolet light of the second wave band so as to carry out UV curing on the glue. According to the UV curing method of the glue, under the condition that an ultraviolet lamp in the UV equipment is not replaced, the ultraviolet rays with the specific wavelength can be emitted, so that the glue with better performance is obtained.

Description

Technical Field

[0001] The present application relates to the field of glue, and in particular to a UV curing method and a curing device for glue. Background Art

[0002] Glue, such as pressure-sensitive adhesive, is a viscoelastic body that has both the viscous properties of a liquid and the elastic properties of a solid. It is widely used in various fields. There are solvent-based, emulsion-based, hot-melt-based and UV-curable types. Among them, the prepolymer of UV-curable glue does not contain solvent, so no additional energy is required for solvent evaporation. The reaction speed during the polymerization process is fast, the energy consumption is small, and it is green and environmentally friendly, and will not pollute the air.

[0003] In the UV light curing system, the photoinitiator is one of the important components of the glue. These photoinitiator molecules have a certain light absorption capacity in the ultraviolet region (250nm~400nm) or the visible region (400nm~800nm), and often have more than one ultraviolet absorption peak. For example, the photoinitiator TPO ((2,4,6-trimethylbenzoyl) diphenylphosphine oxide) has different ultraviolet absorption peaks at 295nm and 380nm, and the corresponding maximum absorption rate is also different, which will also affect the UV curing efficiency and the uniform distribution of molecular weight, and thus affect the performance and quality of the cured glue. However, the ultraviolet lamps used in most UV production lines on the market are low-pressure mercury lamps, which emit ultraviolet wavelengths below 420nm, with a relatively wide wavelength range, and cannot emit ultraviolet rays in a specific wavelength range. Therefore, the performance of the glue cured with them needs to be improved. There are also some related technologies that solve the above problems by replacing ultraviolet lamps that can emit different ultraviolet wavelengths, but often a UV production line has hundreds of ultraviolet lamps, and the replacement process is relatively complicated and costly. Summary of the invention

[0004] Based on this, some embodiments of the present application provide a UV curing method for glue, which can emit ultraviolet rays in a specific wavelength range without replacing the ultraviolet lamp in the UV equipment, thereby obtaining glue with better performance.

[0005] In addition, some other embodiments of the present application also provide a UV curing device for glue.

[0006] A UV curing method for glue comprises the following steps:

[0007] shielding the ultraviolet lamp with a UV blocking film, wherein the UV blocking film can block ultraviolet light of a first wavelength band and allow ultraviolet light of a second wavelength band to pass through;

[0008] The glue is irradiated with ultraviolet light in the second waveband to perform UV curing on the glue.

[0009] In some embodiments, the first wavelength band is 280nm~350nm.

[0010] In some embodiments, the second wavelength band is 380nm~400nm.

[0011] In some embodiments, the UV blocking film contains an ultraviolet absorber, and the ultraviolet absorber includes one or more of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, 2,4-dihydroxybenzophenone, 2-hydroxy 4-methoxybenzophenone, 2-hydroxy 4-n-octyloxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole, monobenzoic acid resorcinol ester and 2-(4,6-diphenyl-1,3,5-triazine-2)-5-n-hexaneoxyphenol.

[0012] In some of the embodiments, the glue contains a first photoinitiator, which includes one or more of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, methyl benzoylformate and 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone.

[0013] In some embodiments, the step of shielding the ultraviolet lamp with a UV blocking film includes:

[0014] The UV blocking adhesive film is installed and fixed between the ultraviolet lamp and the glue, so as to use the UV blocking adhesive film to shield the ultraviolet lamp.

[0015] In some embodiments, the ultraviolet lamp is disposed in a box, and the box includes a bottom plate and a plurality of side plates connected to the bottom plate, and a plurality of side plates are provided with a card slot on a side away from the bottom plate, and the card slot is connected to the UV barrier film by a buckle to install and fix the UV barrier film between the ultraviolet lamp and the glue.

[0016] In some of the embodiments, the adhesive layer material in the UV blocking adhesive film includes acrylic optical adhesive.

[0017] In some of the embodiments, the raw materials for preparing the bonding layer in the UV blocking film include, by weight: 400 to 600 parts of acrylate monomers, 0.5 to 1 part of a second photoinitiator, 0.1 to 0.5 parts of a chain transfer agent, 1 to 2.5 parts of a cross-linking agent, 0.15 to 0.3 parts of a silane coupling agent, and 1 to 5 parts of a UV absorber.

[0018] In some of the embodiments, the acrylic acid ester monomers include 250 to 350 parts by weight of alkyl acrylate and 150 to 250 parts by weight of hydroxy acrylate.

[0019] In some of the embodiments, the alkyl acrylate includes one or more of isooctyl acrylate, isooctyl methacrylate, n-butyl acrylate, lauric acrylate and lauryl methacrylate, and the hydroxy acrylate includes one or more of hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxybutyl acrylate.

[0020] In some embodiments, the second photoinitiator includes one or more of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, methyl benzoylformate and 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone.

[0021] In some embodiments, the second photoinitiator includes (2,4,6-trimethylbenzoyl)diphenylphosphine oxide and 1-hydroxycyclohexylphenyl ketone.

[0022] In some embodiments, the adhesive layer in the UV blocking film is prepared by a method comprising the following steps:

[0023] The acrylate monomer, part of the second photoinitiator and the chain transfer agent are mixed to perform a first polymerization to obtain a prepolymer;

[0024] The prepolymer, the remaining second photoinitiator, the crosslinking agent, the silane coupling agent and the ultraviolet absorber are mixed and subjected to a second polymerization to obtain the bonding layer.

[0025] In some of the embodiments, the thickness of the adhesive layer in the UV blocking film is 100 μm to 120 μm.

[0026] In some of these embodiments, the ultraviolet lamp comprises a low-pressure mercury lamp.

[0027] In some embodiments, the glue includes optical glue.

[0028] A UV curing device for glue comprises an ultraviolet lamp and a UV blocking adhesive film, wherein the UV blocking adhesive film is used to shield the ultraviolet lamp to block ultraviolet light of a first wavelength band and allow ultraviolet light of a second wavelength band to pass through.

[0029] In some of the embodiments, the UV curing device further comprises a box, and the ultraviolet lamp is disposed in the box;

[0030] The box body comprises a bottom plate and a plurality of side plates connected to the bottom plate. A card slot is provided on one side of the side plates away from the bottom plate, and the card slot is buckledly connected to the UV barrier film.

[0031] The curing method of the glue in some embodiments of the present application utilizes a UV blocking film that has a certain UV blocking effect to shield the UV lamp, which can block the UV rays of the first band, and utilize the transmitted UV rays of the second band to induce the photoinitiator in the glue to decompose free radicals, thereby initiating a polymerization reaction, thereby improving the UV curing effect and the uniform distribution of the molecular weight of the glue after curing, and obtaining a glue with better performance. In addition, the UV curing method of the glue of the present application is simpler in process than the traditional method of replacing the UV lamp. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A schematic diagram of a process flow of a UV curing method for glue in some embodiments of the present application;

[0034] Figure 2 A schematic diagram of the structure of a UV curing device for glue in some embodiments of the present application.

[0035] Description of reference numerals: box body 210 , bottom plate 212 , side plate 214 , card slot 2142 , ultraviolet lamp 220 and UV blocking film 230 . DETAILED DESCRIPTION

[0036] In order to facilitate the understanding of the present application, the present application will be described more comprehensively below in conjunction with the specific embodiments. The preferred embodiments of the present application are provided in the specific embodiments. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0038] Unless otherwise specified or there is a contradiction, the terms and phrases used in this application have the following meanings:

[0039] In this application, "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0040] In the description of the present application, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0041] In this application, "one or several" refers to any one, any two or more of the listed items. Among them, "several" refers to any two or more of the listed items.

[0042] In this application, the percentage concentration involved, unless otherwise specified, refers to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of the component.

[0043] In this application, "further", "further", "particularly", "for example", "such as", "example", "for example", etc. are used for descriptive purposes, indicating that the previous and subsequent different technical solutions are related in terms of the content covered, but should not be understood as a limitation on the previous technical solution, nor can it be understood as a limitation on the protection scope of this document. In this document, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0044] In this application, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel schemes of "yes" or "no". If multiple "optional" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent of each other. In this application, descriptions such as "optionally contain", "optionally include", etc. mean "contain or not contain". "Optional component X" means that component X exists or does not exist, or means that component X is contained or not contained.

[0045] When a numerical range is disclosed in this application, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed in this application should be understood to include any and all subranges included therein.

[0046] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0047] The terms "including" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or components that are inherent to these processes, methods, products, or devices.

[0048] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0049] In the flowchart of the present application, although the various steps are displayed in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise clearly stated in the text, the execution of these steps is not strictly restricted in order and they can be performed in other orders. Moreover, at least part of the steps in the figure may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily performed at the same time, but can be performed at different times. Their execution order is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of other sub-steps or stages.

[0050] In the UV light curing system, the photoinitiator is one of the important components of the photocurable glue. After being irradiated by ultraviolet light, the photoinitiator absorbs the energy of light and splits into two active free radicals, which trigger the chain polymerization of the photocurable resin and the active diluent, so that the glue is cross-linked and cured. These photoinitiator molecules have a certain light absorption ability in the ultraviolet light region (250nm~400nm) or the visible light region (400nm~800nm). They often have more than one ultraviolet absorption peak, and the corresponding maximum absorption rate is also different, which will also affect the UV curing efficiency and the uniform distribution of molecular weight. Some optical adhesives (OCA) on the market that can be cured twice are realized by using the ultraviolet absorption of different wavelengths of the photoinitiator. For example, a fully bonded OCA optical adhesive for curved screens is disclosed in the related art. After the optical glue is made into an optical adhesive film, it is first irradiated with medium-wave ultraviolet light. The wavelength of ultraviolet light is 330nm~420nm, which only activates the photoinitiator TPO, so that the optical glue is cured once to obtain a semi-cured optical adhesive soft film. After the optical adhesive is bonded, it is irradiated with short-wave ultraviolet light with a wavelength of 220nm~310nm. The photoinitiator 6992 is activated for secondary curing to achieve true curing and bonding. At the same time, (meth)acrylates (such as glycidyl methacrylate) and cationic photoinitiators with cationic heterocyclic alkane structures are further cross-linked and cured when irradiated with short-wavelength radiation, thereby increasing the tensile strength and bonding force of the adhesive film. This secondary curing method facilitates the transportation and use of the optical adhesive and has a good bonding effect.

[0051] However, it is precisely because the photoinitiator has more than one wavelength of ultraviolet absorption peaks, and the ultraviolet lamps used in most UV production lines on the market are low-pressure mercury lamps, which emit ultraviolet wavelengths below 420nm, with a relatively wide range. Within this wide range, the photoinitiator has multiple absorption peaks, which has a greater impact on the performance and quality of the cured glue.

[0052] Based on this, the first aspect of the present application provides a UV curing method for glue, please refer to Figure 1 , including the following steps S110 and S120:

[0053] Step S110: shielding the ultraviolet lamp with a UV blocking film, wherein the UV blocking film can block ultraviolet light of a first wavelength band and allow ultraviolet light of a second wavelength band to pass through.

[0054] Step S120: irradiating the glue with ultraviolet light in the second wavelength band to UV-cure the glue.

[0055] The UV curing method of the glue in some embodiments of the present application utilizes a UV blocking film that has a certain blocking effect on ultraviolet rays to shield the ultraviolet lamp, which can block ultraviolet rays of the first band, and utilize the transmitted ultraviolet rays of the second band to induce the curing of the glue. By optimizing the UV curing process of the glue, a glue with better performance is obtained. Compared with the traditional method of replacing the ultraviolet lamp, the process is simpler. Therefore, the UV curing method of the glue in some embodiments of the present application can utilize the shielding of the UV blocking film to block the ultraviolet rays of the first band without replacing the ultraviolet lamp in the UV equipment, and realize the emission of ultraviolet rays of a specific wavelength, so that the photoinitiator in the glue is efficiently decomposed to induce a polymerization reaction.

[0056] In some embodiments, the first wavelength range is 200 nm to 350 nm. For example, the first wavelength range may be, but is not limited to, 200 nm, 220 nm, 250 nm, 280 nm, 300 nm, 320 nm, 340 nm, 350 nm, or a range consisting of any two of these values. Optionally, the first wavelength range is 280 nm to 350 nm.

[0057] In some embodiments, the second wavelength range is 350 nm to 420 nm. For example, the second wavelength range may be, but is not limited to, 350 nm, 360 nm, 380 nm, 400 nm, 420 nm, or a range consisting of any two of these values. Optionally, the second wavelength range is 380 nm to 400 nm.

[0058] In some embodiments, the glue contains a first photoinitiator. The first photoinitiator has an absorption peak under ultraviolet light in the second band, so that under the irradiation of ultraviolet light in the second band, the first photoinitiator decomposes free radicals and initiates a polymerization reaction, thereby improving the UV curing effect and the uniform distribution of the molecular weight of the glue. It can be understood that the specific type of the first photoinitiator is not particularly limited, and it can have an absorption peak under ultraviolet light in the second band. For example, the first photoinitiator includes one or more of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylacetone, methyl benzoylformate and 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone.

[0059] In some embodiments, the UV blocking film contains an ultraviolet absorber, and the ultraviolet absorber includes one or more of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, 2,4-dihydroxybenzophenone, 2-hydroxy 4-methoxybenzophenone, 2-hydroxy 4-n-octyloxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole, monobenzoic acid resorcinol ester and 2-(4,6-diphenyl-1,3,5-triazine-2)-5-n-hexaneoxyphenol.

[0060] In one example, the UV absorber includes 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol.

[0061] In some embodiments, the step of shielding the ultraviolet lamp with a UV blocking film includes:

[0062] The UV blocking film is installed and fixed between the UV lamp and the glue to shield the UV lamp with the UV blocking film.

[0063] Specifically, the UV lamp is arranged in a box body, and the box body includes a bottom plate and a plurality of side plates connected to the bottom plate. A card slot is provided on the side of the plurality of side plates away from the bottom plate, and the card slot is connected to the UV barrier film buckle to install and fix the UV barrier film between the UV lamp and the glue. The UV barrier film is installed and fixed between the UV lamp and the glue by the above method. When the glue is UV-cured, it is only necessary to install and fix the UV barrier film between the UV lamp and the glue without replacing multiple UV lamps, and the process is simpler. It can be understood that the above only provides a method for installing and fixing the UV barrier film between the UV lamp and the glue, but it is not limited to this. The UV barrier film can also be fixed and installed by other commonly used methods.

[0064] In some embodiments, the adhesive layer material in the UV blocking adhesive film includes acrylate optical adhesive. Acrylate optical adhesive has good pressure sensitivity, adhesion and weather resistance.

[0065] Specifically, the raw materials for preparing the bonding layer include, by weight: 400 to 600 parts of acrylate monomers, 0.5 to 1 part of a second photoinitiator, and 1 to 5 parts of an ultraviolet absorber. Further, the raw materials for preparing the bonding layer include: 400 to 600 parts of acrylate monomers, 0.5 to 1 part of a second photoinitiator, 0.1 to 0.5 parts of a chain transfer agent, 1 to 2.5 parts of a crosslinking agent, 0.15 to 0.3 parts of a silane coupling agent, and 1 to 5 parts of an ultraviolet absorber.

[0066] In some embodiments, the acrylate monomer includes alkyl acrylate and hydroxy acrylate. Specifically, by weight, the acrylate monomer includes 250 to 350 parts of alkyl acrylate and 150 to 250 parts of hydroxy acrylate. At this time, by weight, the raw materials for preparing the bonding layer include: 250 to 350 parts of alkyl acrylate, 150 to 250 parts of hydroxy acrylate, 0.5 to 1 part of the second photoinitiator, 0.1 to 0.5 parts of the chain transfer agent, 1 to 2.5 parts of the crosslinking agent, 0.15 to 0.3 parts of the silane coupling agent and 1 to 5 parts of the ultraviolet absorber.

[0067] Specifically, the alkyl acrylate includes one or more of isooctyl acrylate, isooctyl methacrylate, n-butyl acrylate, lauric acrylate and lauryl methacrylate, and the hydroxy acrylate includes one or more of hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxybutyl acrylate.

[0068] In one example, the acrylic acid ester monomers include isooctyl acrylate and hydroxybutyl acrylate. Specifically, by weight, the raw materials for preparing the bonding layer include: 250 to 350 parts of isooctyl acrylate, 150 to 250 parts of hydroxybutyl acrylate, 0.5 to 1 part of the second photoinitiator, 0.1 to 0.5 parts of the chain transfer agent, 1 to 2.5 parts of the crosslinking agent, 0.15 to 0.3 parts of the silane coupling agent, and 1 to 5 parts of the ultraviolet absorber.

[0069] In some embodiments, the second photoinitiator includes one or more of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, methyl benzoylformate, and 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone. In some of these embodiments, the second photoinitiator includes (2,4,6-trimethylbenzoyl) diphenylphosphine oxide and 1-hydroxycyclohexyl phenyl ketone.

[0070] In some embodiments, the silane coupling agent includes one or more of vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tri(β-methoxyethoxy)silane, and γ-glycidoxypropyltrimethoxysilane.

[0071] In some embodiments, the chain transfer agent includes one or more of 1-dodecanethiol and mercaptoethanol.

[0072] In some embodiments, the crosslinking agent includes one or more of 1,6-hexanediol diacrylate and dipentaerythritol pentapropionate.

[0073] It can be understood that only some relatively specific components are given above, but it is not limited thereto, and other components commonly used in the art may also be used.

[0074] In some embodiments, the adhesive layer in the UV blocking film is prepared by a method comprising the following steps:

[0075] Mixing an acrylate monomer, a portion of a second photoinitiator and a chain transfer agent, and performing a first polymerization to obtain a prepolymer;

[0076] The prepolymer, the remaining second photoinitiator, the crosslinking agent, the silane coupling agent and the ultraviolet absorber are mixed and subjected to a second polymerization to obtain a bonding layer.

[0077] Specifically, the first polymerization step is carried out under an ultraviolet lamp for 5 minutes to 8 minutes. Furthermore, the wattage of the ultraviolet lamp is 18w to 40w.

[0078] Specifically, in the second polymerization step, the polymerization is carried out under ultraviolet light with a wavelength of 300nm to 400nm, and the total energy irradiation is 2000mJ / cm 2 ~4000mJ / cm 2 , time is 10min~15min.

[0079] In one embodiment, both the first polymerization and the second polymerization are carried out under a protective atmosphere, and the protective atmosphere may be, but is not limited to, nitrogen, argon, etc.

[0080] By mixing acrylate monomers with cross-linking agents, second photoinitiators, chain transfer agents, silane coupling agents and ultraviolet absorbers, a fully cured optically transparent adhesive is obtained through a one-time UV curing method. As the bonding layer of the UV blocking adhesive film, it has a certain barrier effect on ultraviolet rays. When it is attached to the ultraviolet lamp in the UV curing device, it can block some wavelengths of ultraviolet rays, and use the remaining wavelengths of ultraviolet rays to induce the photoinitiator in the glue to decompose free radicals and initiate a polymerization reaction, thereby obtaining a glue with better performance.

[0081] In some embodiments, the thickness of the adhesive layer in the UV blocking film is 100 μm to 120 μm. For example, the thickness of the adhesive layer in the UV blocking film can be, but is not limited to, 100 μm, 102 μm, 105 μm, 108 μm, 110 μm, 112 μm, 115 μm, 118 μm, 120 μm, or a range consisting of any two of these values.

[0082] In some embodiments, the UV blocking adhesive film further comprises a release film, which is disposed on two opposite sides of the adhesive layer to support the adhesive layer. Specifically, during the preparation of the adhesive layer, the mixture obtained before the second polymerization is coated between two layers of release films, and then the second polymerization is performed to obtain the adhesive layer and the release films disposed on both sides of the adhesive layer.

[0083] Specifically, the release film may be one commonly used in the art and is not particularly limited herein, such as a polyethylene terephthalate (PET) release film.

[0084] Specifically, the thickness of each release film may be, but is not limited to, 100 μm. It is understood that the material and thickness of the release films on both sides may be the same or different, and are not particularly limited.

[0085] In some embodiments, the ultraviolet lamp comprises a low-pressure mercury lamp. Specifically, the mercury vapor pressure of the low-pressure mercury lamp is 1.3 Pa to 13 Pa (ie, 0.01 mmHg to 0.1 mmHg).

[0086] In some embodiments, the glue includes optical glue. Optical glue (OCA, Optically Clear Adhesive) is a special adhesive used to glue transparent optical elements (such as lenses, etc.), which belongs to the category of pressure-sensitive adhesive. Optical glue has high performance requirements and large demand, and its market competitiveness is also large. The preparation method of some embodiments of the present application can obtain optical glue with better performance, which is conducive to meeting the market demand for high-performance optical glue.

[0087] The specific composition of the glue is not particularly limited in the present application, as long as it can be cured under ultraviolet light.

[0088] A second aspect of the present application provides a UV curing device for glue, comprising an ultraviolet lamp and a UV blocking film, wherein the UV blocking film is used to shield the ultraviolet lamp to block ultraviolet light of a first wavelength band and allow ultraviolet light of a second wavelength band to pass through.

[0089] The specific UV blocking film and UV lamp are as described above and will not be described again here.

[0090] In some embodiments, see Figure 2 The UV curing device also includes a box body 210 , and an ultraviolet lamp 220 is disposed in the box body 210 .

[0091] Specifically, the box body 210 includes a bottom plate 212 and a plurality of side plates 214 connected to the bottom plate 212 . A slot 2142 is provided on one side of the side plates 214 away from the bottom plate 212 . The slot 2142 is snap-connected to the UV blocking film 230 .

[0092] In some embodiments, there are multiple ultraviolet lamps 220 , and the multiple ultraviolet lamps 220 are all placed in the box 210 .

[0093] The above-mentioned UV curing device includes an ultraviolet lamp and a UV blocking film. During the UV curing process, the UV blocking film with a certain blocking effect on ultraviolet rays is used to shield the ultraviolet lamp, which can block ultraviolet rays in the first band, and the transmitted ultraviolet rays in the second band are used to induce the first photoinitiator in the glue to decompose free radicals and initiate a polymerization reaction, thereby improving the UV curing effect and the uniform distribution of the molecular weight of the glue after curing, and obtaining glue with better performance.

[0094] In order to make the purpose and advantages of the present application clearer, the UV curing method of the glue of the present application and its effect are further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and shall not be used to limit the present application. The following embodiments do not include other components except inevitable impurities unless otherwise specified. The drugs and instruments used in the embodiments are conventionally selected in the art unless otherwise specified. The experimental methods for which specific conditions are not specified in the embodiments are implemented according to conventional conditions, such as the conditions described in the literature and books or the methods recommended by the manufacturer.

[0095] Example 1

[0096] This embodiment provides a UV blocking film, and the preparation method thereof comprises the following steps:

[0097] In a 1000mL three-necked flask equipped with a stirring paddle, a nitrogen inlet and a thermometer, the following reagents were added in mass fractions: 300 parts of isooctyl acrylate, 200 parts of hydroxybutyl acrylate, 0.5 parts of 1-hydroxycyclohexyl phenyl ketone and 0.1 parts of 1-dodecanethiol. After the three-necked flask was passed through high-purity (99.99%) nitrogen for 1 hour, an 18w ultraviolet lamp was turned on for the first polymerization reaction for 5 minutes to obtain a prepolymer with a viscosity of about 400cps. After the first polymerization reaction was completed, 1.5 parts of 1,6-hexanediol diacrylate, 0.15 parts of a silane coupling agent, 0.5 parts of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide and 1.2 parts of an ultraviolet absorber 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol were added to the prepolymer. After thorough mixing and degassing, the resulting mixture was coated on two layers of 100 μm thick silicone-treated polyethylene terephthalate (PET) release liner. The resulting PET liner / mixture / PET liner was then exposed to ultraviolet radiation with a spectral output of 300nm~400nm and a total energy exposure of 2000mJ / cm 2 , time is 10min, and the second polymerization is carried out to obtain a UV barrier film with an adhesive layer thickness of 100μm.

[0098] Example 2

[0099] This embodiment provides a UV blocking film, and the preparation method thereof comprises the following steps:

[0100] In a 1000mL three-necked flask equipped with a stirring paddle, a nitrogen inlet and a thermometer, the following reagents were added by mass: 300 parts of isooctyl acrylate, 200 parts of hydroxybutyl acrylate, 0.5 parts of 1-hydroxycyclohexyl phenyl ketone and 0.1 parts of 1-dodecanethiol. After the three-necked flask was passed through high-purity (99.99%) nitrogen for 1 hour, an 18w ultraviolet lamp was turned on to react and the first polymerization reaction was carried out for 5 minutes to obtain a prepolymer with a viscosity of about 400cps. After the first polymerization reaction was completed, 1.5 parts of 1,6-hexanediol diacrylate, 0.15 parts of silane coupling agent, 0.5 parts of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide and 4.7 parts of ultraviolet absorber 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol were added to the prepolymer. After thorough mixing and degassing, the resulting mixture was coated on two layers of 100 μm thick silicone-treated polyethylene terephthalate (PET) release liner. The resulting PET liner / mixture / PET liner was then exposed to ultraviolet radiation with a spectral output of 300nm~400nm and a total energy exposure of 2000mJ / cm 2 , and a second polymerization was carried out for 10 min to obtain a UV-blocking adhesive film with an adhesive layer thickness of 100 μm.

[0101] Comparative Example 1

[0102] Comparative Example 1 provides a barrier film, and its preparation steps are the same as those of Example 1, except that no ultraviolet absorber is added.

[0103] The UV transmittance of the UV barrier films prepared in Examples 1-2 and the barrier film of Comparative Example 1 was tested, and the test method and results are as follows:

[0104] Test method: Use the test instrument CS-700 to cut the UV barrier film into 50mm×60mm sheets, remove the two layers of substrate-free release films, and make the adhesive layer fit the glass plate. Perform a spectrophotometric colorimetric test to observe the transmittance of light of different wavelengths.

[0105] The test results are shown in Table 1 below:

[0106] Table 1

[0107]

[0108] Example 3

[0109] This embodiment provides a UV curing method for glue, comprising the following steps:

[0110] The UV barrier film with an adhesive layer thickness of 100 μm obtained in the above Example 1 is cut into sheets, four slots are set in the box of the UV curing equipment, and the covering film is buckled and connected in the slots to be fixed above the ultraviolet lamp.

[0111] The following reagents were added to a 1000 mL three-necked flask equipped with a stirring paddle, a nitrogen inlet and a thermometer: 260 g of isooctyl acrylate, 125 g of isooctyl methacrylate, 75 g of hydroxyethyl acrylate, 40 g of isobornyl acrylate, 0.5 g of 1-hydroxycyclohexyl phenyl ketone and 0.4 g of 1-dodecanethiol. After the above device was passed through high-purity (99.99%) nitrogen for 1 hour, an 18W UV lamp was turned on for 5 minutes to obtain a prepolymer with a viscosity of about 400 cps. After the polymerization reaction, 0.5 g of 1,6-hexanediol diacrylate, 0.5 g of silane coupling agent, 0.5 g of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 0.5 g of triarylsulfonium salt photoinitiator 6990 and 25 g of glycidyl methacrylate were added to the prepolymer. After thorough mixing and degassing, the resulting mixture was coated on two layers of 100 μm thick silicone-treated polyethylene terephthalate (PET) release liner. The resulting PET liner / mixture / PET liner laminate was then exposed to UV light shielded with a UV barrier film for UV curing. The spectral output was 300-400 nm UV radiation, with a total energy exposure of 2000 mJ / cm 2 , an OCA film with a thickness of 250 μm was obtained.

[0112] Example 4

[0113] This embodiment provides a UV curing method for glue, comprising the following steps:

[0114] The UV barrier film with an adhesive layer thickness of 100 μm obtained in the above Example 2 is cut into sheets, four slots are set in the box of the UV curing equipment, and the covering film is buckled and connected in the slots to be fixed above the ultraviolet lamp.

[0115] The following reagents were added to a 1000 mL three-necked flask equipped with a stirring paddle, a nitrogen inlet and a thermometer: 260 g of isooctyl acrylate, 125 g of isooctyl methacrylate, 75 g of hydroxyethyl acrylate, 40 g of isobornyl acrylate, 0.5 g of 1-hydroxycyclohexyl phenyl ketone and 0.4 g of 1-dodecanethiol. After the above device was passed through high-purity (99.99%) nitrogen for 1 hour, an 18W UV lamp was turned on for 5 minutes to obtain a prepolymer with a viscosity of about 400 cps. After the polymerization reaction, 0.5 g of 1,6-hexanediol diacrylate, 0.5 g of silane coupling agent, 0.5 g of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1.5 g of 4-acryloylhydroxybenzoic acid benzophenone and 25 g of glycidyl methacrylate were added to the prepolymer. After thorough mixing and degassing, the resulting mixture was coated on two 100 μm thick silicone-treated polyethylene terephthalate (PET) release liners. The resulting PET liner / mixture / PET liner laminate was then exposed to UV light shielded with a UV-blocking film for UV curing. The spectral output was 300 nm to 400 nm UV radiation, with a total energy exposure of 2000 mJ / cm 2 , an OCA film with a thickness of 250 μm was obtained.

[0116] Comparative Example 2

[0117] Comparative Example 2 provides a UV curing method for glue, which is similar to the UV curing method for glue in Example 3, except that the ultraviolet lamp is not shielded.

[0118] Comparative Example 3

[0119] Comparative Example 3 provides a UV curing method for glue, which is similar to the UV curing method for glue in Example 4, except that the ultraviolet lamp is not shielded.

[0120] The properties of the OCA adhesive after curing in the above-mentioned Examples 3 and 4, Comparative Examples 2 and 3 were tested, as follows:

[0121] 1. Adhesive layer hardness test

[0122] Using the hardness tester DTAA‖ from Germany, the OCA glue was cut and stacked into a glue layer with a thickness of 2000 microns. The two layers of substrate-free release film were torn off to make the glue layer fit the glass plate and carry out hardness performance test.

[0123] 2. Adhesion test of adhesive layer

[0124] The side of the OCA glue with less release force was torn off and covered on a non-release PET film. A sample with a length of 15 cm and a width of 2.5 cm was cut and placed on a glass plate for 20 minutes before testing its adhesion.

[0125] 3. Aging resistance test

[0126] The OCA glue is bonded to the display module to form a laminate (CG+OCA+OC). The laminate is then irradiated with ultraviolet light without a masking film and with a spectral output of 300-400nm. The total energy exposure is 2,000mJ / cm2. After the samples are placed in high temperature (95°C) and high temperature and high humidity environment (85°C, 85%RH) for 500 hours, the laminate is observed to see if there will be any adverse phenomena such as bubble rebound.

[0127] Table 2

[0128]

[0129] It can be seen from the above-mentioned Examples 3 and 4 that by adding two photoinitiators with different ultraviolet absorption wavelengths, using the UV blocking film to block the ultraviolet rays with a low wavelength of 200nm~350nm, the photoinitiator with a high wavelength absorption peak of 350nm~420nm is cracked, inducing a polymerization reaction, and the OCA glue is bonded to the display module to form a laminate (CG+OCA+OC), which is then irradiated for the second time by ultraviolet rays with no covering film and a spectral output of 300nm~400nm. The OCA glue obtained by the first UV blocking film shielding the ultraviolet lamp curing has a relatively small hardness, has a better ink step filling effect, and has better anti-aging performance.

[0130] Therefore, when using the UV curing method of the embodiment of the present application, each time light curing of a specific ultraviolet wavelength is required, it is only necessary to shield the UV lamp with the UV blocking film, which is more efficient and convenient than replacing UV lamps of different wavelengths.

[0131] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0132] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the contents of the attached claims, and the description and drawings can be used to explain the contents of the claims.

Claims

1. A UV curing method for glue, characterized in that: The steps include: shielding the ultraviolet lamp with a UV blocking film, wherein the UV blocking film can block ultraviolet light of a first wavelength band and allow ultraviolet light of a second wavelength band to pass through; The glue is irradiated with ultraviolet light in the second waveband to perform UV curing on the glue.

2. The UV curing method of glue according to claim 1, characterized in that: The first waveband is 280nm~350nm; Optionally, the second wavelength band is 380nm~400nm.

3. The UV curing method of glue according to claim 2, characterized in that: The UV blocking film contains an ultraviolet absorber, and the ultraviolet absorber includes one or more of 2-(2H-benzotriazole-2-yl)-6-dodecyl-4-methylphenol, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole, monobenzoic acid resorcinol ester and 2-(4,6-diphenyl-1,3,5-triazine-2)-5-n-hexyloxyphenol; And / or, the glue contains a first photoinitiator, and the first photoinitiator includes one or more of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, methyl benzoylformate and 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone.

4. The UV curing method of glue according to claim 1, characterized in that: The steps to shield UV light with UV blocking film include: The UV blocking adhesive film is installed and fixed between the UV lamp and the glue, so as to shield the UV lamp with the UV blocking adhesive film; Optionally, the ultraviolet lamp is arranged in a box body, and the box body includes a bottom plate and multiple side plates connected to the bottom plate, and the multiple side plates are provided with a card slot on the side away from the bottom plate, and the card slot is connected to the UV barrier film by a buckle to install and fix the UV barrier film between the ultraviolet lamp and the glue.

5. The UV curing method of glue according to any one of claims 1 to 4, characterized in that: The adhesive layer material in the UV blocking adhesive film includes an acrylic optical adhesive; Optionally, the raw materials for preparing the bonding layer in the UV blocking film include, by weight: 400 to 600 parts of acrylate monomers, 0.5 to 1 part of a second photoinitiator, 0.1 to 0.5 parts of a chain transfer agent, 1 to 2.5 parts of a cross-linking agent, 0.15 to 0.3 parts of a silane coupling agent, and 1 to 5 parts of an ultraviolet absorber.

6. The UV curing method of glue according to claim 5, characterized in that: Meet one or more of the following conditions: (1) The acrylic acid ester monomer comprises 250 to 350 parts by weight of alkyl acrylate and 150 to 250 parts by weight of hydroxy acrylate; Optionally, the alkyl acrylate includes one or more of isooctyl acrylate, isooctyl methacrylate, n-butyl acrylate, lauric acrylate and lauryl methacrylate, and the hydroxy acrylate includes one or more of hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxybutyl acrylate; (2) The second photoinitiator includes one or more of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, methyl benzoylformate and 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone; Optionally, the second photoinitiator includes (2,4,6-trimethylbenzoyl)diphenylphosphine oxide and 1-hydroxycyclohexylphenyl ketone.

7. The UV curing method of glue according to claim 5, characterized in that: The adhesive layer in the UV barrier film is prepared by a method comprising the following steps: The acrylate monomer, part of the second photoinitiator and the chain transfer agent are mixed to perform a first polymerization to obtain a prepolymer; The prepolymer, the remaining second photoinitiator, the crosslinking agent, the silane coupling agent and the ultraviolet absorber are mixed and subjected to a second polymerization to obtain the bonding layer.

8. The UV curing method of glue according to claim 5, characterized in that: The thickness of the adhesive layer in the UV blocking film is 100 μm to 120 μm.

9. The UV curing method of glue according to any one of claims 1 to 4 and 6 to 8, characterized in that: The ultraviolet lamp comprises a low-pressure mercury lamp; And / or, the glue includes optical glue.

10. A UV curing device for glue, characterized in that: It comprises an ultraviolet lamp and a UV blocking film, wherein the UV blocking film is used to shield the ultraviolet lamp to block ultraviolet light of a first wavelength band and allow ultraviolet light of a second wavelength band to pass through.

11. The UV curing device for glue according to claim 10, characterized in that: The UV curing device also includes a box, and the ultraviolet lamp is arranged in the box; The box body comprises a bottom plate and a plurality of side plates connected to the bottom plate. A plurality of side plates are provided with a card slot on one side away from the bottom plate, and the card slot is connected with the UV barrier film by a buckle.

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