UV curing acrylate pressure-sensitive adhesive and preparation method thereof, and pressure-sensitive adhesive film

Abstract

The present application relates to a UV-curable acrylate pressure-sensitive adhesive, a preparation method, and a pressure-sensitive adhesive film. The UV-curable acrylate pressure-sensitive adhesive comprises the following raw materials, by mass percentage: a monofunctional acrylate soft monomer: 55% to 75%; a monofunctional acrylate hard monomer: 12% to 20%; a multifunctional monomer containing at least two polymerizable double bonds: 1% to 5%; an acrylate functional monomer: 1% to 10%; a first photoinitiator: 0.01% to 1%; a second photoinitiator: 0.01% to 1%; a phosphorus-containing monomer: 1% to 5%; and a flame retardant Doher‑601: 5% to 15%. The UV-curable acrylate pressure-sensitive adhesive of the present application has high flame retardancy, high peel strength, and high cohesive strength and bonding strength.

Description

Technical Field

[0001] The present application relates to the technical field of pressure-sensitive adhesive materials, and in particular to a UV-curable acrylate pressure-sensitive adhesive and a preparation method thereof, and a pressure-sensitive adhesive film. Background Art

[0002] UV curing acrylic pressure sensitive adhesive is well known for its fast curing, low energy consumption, environmental friendliness and excellent pressure sensitive properties of cross-linked products, and has become a bonding solution favored by many industries. Its application range is wide, spanning multiple key fields such as electronic manufacturing, optical devices, automotive industry, medical and health care, and even home decoration, fully demonstrating its high applicability and flexibility.

[0003] However, as a polymer, acrylic pressure-sensitive adhesive will decompose into unstable flammable components when exposed to high temperature or ignition, which may cause fire. In order to ensure the safety of adhesive tape during use and transportation, it is necessary to give it flame retardant properties. The traditional method is to achieve the flame retardant effect by adding sufficient flame retardant to the pressure-sensitive adhesive. However, as the amount of flame retardant added increases, the bonding performance, toughness and pressure-sensitive properties of the pressure-sensitive adhesive are often adversely affected.

[0004] Therefore, how to develop a UV-curable acrylic pressure-sensitive adhesive with high-efficiency flame retardant properties, environmental protection and excellent performance has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] Based on this, in order to solve the above problems, the present application provides a UV-curable acrylate pressure-sensitive adhesive and a preparation method thereof, and a pressure-sensitive adhesive film to solve the above technical problems.

[0006] The first aspect of the present application provides a UV-curable acrylate pressure-sensitive adhesive, which comprises the following raw materials, measured by mass percentage:

[0007] Monofunctional acrylic soft monomer: 55% to 75%;

[0008] Monofunctional acrylic hard monomer: 12% to 20%;

[0009] Multifunctional monomers containing at least two polymerizable double bonds: 1% to 5%;

[0010] Acrylate functional monomer: 1% to 10%;

[0011] First photoinitiator: 0.01% to 1%;

[0012] Second photoinitiator: 0.01% to 1%;

[0013] Phosphorus-containing monomers: 1% to 5%;

[0014] Flame retardant Doher-601: 5%~15%.

[0015] In some embodiments, the monofunctional acrylic soft monomer includes one or more of n-butyl acrylate, isooctyl acrylate, lauryl acrylate, and caprolactone acrylate.

[0016] In some embodiments, the monofunctional acrylic hard monomer includes one or more of isobornyl acrylate, isobornyl methacrylate, isooctyl methacrylate, acryloylmorpholine, methyl acrylate, and methyl methacrylate.

[0017] In some embodiments, the multifunctional monomer containing at least two polymerizable double bonds includes one or more of hexanediol diacrylate (HDDA), ethoxylated bisphenol A diacrylate (BPA3EODA), ethoxylated trimethylolpropane triacrylate (EO-TMPTA), trimethylolpropane triacrylate (TMPTA), and propoxylated glycerol triacrylate (GPTA).

[0018] In some embodiments, the acrylate functional monomer includes one or more of acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, acrylamide, and glycidyl acrylate.

[0019] In some embodiments, the first photoinitiator and the second photoinitiator respectively include one or more of benzoin diethyl ether (Omnirad 651), 1-hydroxycyclohexyl phenyl ketone (Irgacure 184), diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure 819), 2-methyl-4-methylthio-2-morpholinopropiophenone (Irgacure 907), and 2-hydroxy-2methyl-1-phenylpropiophenone (Darocure 1173).

[0020] In some embodiments, the phosphorus-containing monomer is acrylic phosphorus-containing monomer PAM-200 and / or acrylic phosphorus-containing monomer PAM-300.

[0021] The second aspect of the present application provides a method for preparing the UV-curable acrylate pressure-sensitive adhesive provided in the first aspect, comprising the following steps:

[0022] S1. Evenly mix a monofunctional acrylate soft monomer, a monofunctional acrylate hard monomer, a portion of a multifunctional monomer containing at least two polymerizable double bonds, an acrylate functional monomer, a first photoinitiator, a phosphorus-containing monomer, and a portion of a flame retardant to prepare a mixture;

[0023] S2, irradiating the mixture with UV to obtain a prepolymer;

[0024] S3, compounding the prepolymer, the remaining flame retardant, the remaining multifunctional monomer containing at least two polymerizable double bonds and the second photoinitiator, and mixing them evenly to obtain a UV-curable acrylate pressure-sensitive adhesive.

[0025] In some embodiments, in step S2, a 1 MW to 30 MW ultraviolet lamp with a wavelength of 100 nm to 400 nm is used to irradiate the mixture.

[0026] The third aspect of the present application provides a pressure-sensitive adhesive film, which is prepared by the following preparation method:

[0027] The UV-curable acrylate pressure-sensitive adhesive provided in the first aspect or the UV-curable acrylate pressure-sensitive adhesive prepared according to the preparation method provided in the second aspect is coated on a release film substrate, and the release film is covered on the upper surface of the acrylate pressure-sensitive adhesive, and UV light curing treatment is performed to prepare a pressure-sensitive adhesive film.

[0028] The present application adds a specific flame retardant Doher-601 into a UV-curing acrylic pressure-sensitive adhesive system. Under UV curing conditions, the flame retardant causes a photoinitiator in the system to absorb energy and decompose into ultra-highly active free radicals, which then initiates chemical internal crosslinking and branching reactions of phosphorus-containing monomers, flame retardants, monofunctional soft and hard monomers, monofunctional hard monomers, multifunctional monomers containing polymerizable double bonds, and functional monomers in the system. The flame retardant directly participates in the entire reaction system, and a bulk polymerized flame-retardant adhesive is obtained through chemical crosslinking modification, thereby achieving a relatively efficient flame retardant effect with a relatively low content of flame retardant. The UV-curing acrylic pressure-sensitive adhesive prepared by adopting the formula has the characteristics of high transparency, high peel strength, does not contain any organic solvents, and is environmentally friendly and energy-saving.

[0029] The present application improves the adhesive force of the pressure-sensitive adhesive by adding monofunctional acrylic soft monomers into the UV curing acrylic pressure-sensitive adhesive system. The long side chain alkyl groups of these monomers can weaken the interaction between the main chains of the polymer, achieve the internal plasticization effect, and reduce the glass transition temperature of the pressure-sensitive adhesive. At the same time, the introduction of acrylic functional monomers, the functional groups such as carboxyl, hydroxyl, and amine carried by these monomers themselves, under the action of intermolecular polar forces and hydrogen bonds, improve the cohesive strength and bonding strength of the pressure-sensitive adhesive. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a process flow chart of a method for preparing an acrylic pressure-sensitive adhesive in one embodiment of the present application. DETAILED DESCRIPTION

[0031] References to embodiments of the present application will now be provided in detail, one or more embodiments of which are described below. Each embodiment is provided as an explanation rather than a limitation of the present application. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present application without departing from the scope or spirit of the present application. For example, a feature described or described as part of one embodiment may be used in another embodiment to produce a further embodiment.

[0032] Therefore, it is intended that the present application covers such modifications and variations that fall within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present application are disclosed in or are apparent from the following detailed description. It will be appreciated by those of ordinary skill in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the present application.

[0033] 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.

[0034] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each 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 merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0035] In this article, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 100-150nm means that the units of the left endpoint "100" and the right endpoint "150" are both nm (nanometers).

[0036] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0037] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0038] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, it is mentioned that the method may also include step (c), which means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0039] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0040] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0041] UV-curable acrylic pressure-sensitive adhesives are known for their fast curing, low energy consumption, environmental friendliness, and excellent pressure-sensitive properties of their cross-linked products, making them a favored bonding solution in many industries. However, as acrylic pressure-sensitive adhesives are polymers, they will decompose into unstable flammable components when exposed to high temperatures or ignited, which may cause fires. To ensure the safety of adhesive tapes during use and transportation, the traditional method is to add sufficient flame retardants to the pressure-sensitive adhesive to achieve a flame retardant effect. However, as the amount of flame retardant added increases, the bonding performance, toughness, and pressure-sensitive properties of the pressure-sensitive adhesive are often adversely affected.

[0042] The flame-retardant acrylic pressure-sensitive adhesives currently on the market generally have the following problems: (1) Halogen flame retardants are used in pressure-sensitive adhesives. Although they have a good flame retardant effect, they will produce toxic and corrosive gases. (2) Inorganic flame retardants are used in pressure-sensitive adhesives. Although they produce less smoke and no toxic gases when burned, the amount added is large, which will affect the appearance and performance of the adhesive film. (3) The addition of flame retardants causes the pressure sensitivity of pressure-sensitive adhesives to decrease significantly.

[0043] Based on this, in order to solve the above problems, the first aspect of the present application provides a UV-curable acrylate pressure-sensitive adhesive, which comprises the following raw materials in terms of mass percentage:

[0044] Monofunctional acrylic soft monomer: 55% to 75%;

[0045] Monofunctional acrylic hard monomer: 12% to 20%;

[0046] Multifunctional monomers containing at least two polymerizable double bonds: 1% to 5%;

[0047] Acrylate functional monomer: 1% to 10%;

[0048] First photoinitiator: 0.01% to 1%;

[0049] Second photoinitiator: 0.01% to 1%;

[0050] Phosphorus-containing monomers: 1% to 5%;

[0051] Flame retardant Doher-601: 5%~15%.

[0052] In some embodiments, the mass percentage of the flame retardant Doher-601 is 5% to 15%. Preferably, the mass percentage of the flame retardant Doher-601 is 10%.

[0053] In some embodiments, the monofunctional acrylic soft monomer includes one or more of n-butyl acrylate, isooctyl acrylate, lauryl acrylate, and caprolactone acrylate.

[0054] In some embodiments, the monofunctional acrylic hard monomer includes one or more of isobornyl acrylate, isobornyl methacrylate, isooctyl methacrylate, acryloylmorpholine, methyl acrylate, and methyl methacrylate.

[0055] In some embodiments, the multifunctional monomer containing at least two polymerizable double bonds includes one or more of hexanediol diacrylate (HDDA), ethoxylated bisphenol A diacrylate (BPA3EODA), ethoxylated trimethylolpropane triacrylate (EO-TMPTA), trimethylolpropane triacrylate (TMPTA), and propoxylated glycerol triacrylate (GPTA).

[0056] In some embodiments, the acrylate functional monomer includes one or more of acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, acrylamide, and glycidyl acrylate.

[0057] In some embodiments, the first photoinitiator and the second photoinitiator are free radical initiators, which absorb energy of a certain wavelength under UV (ultraviolet light) to generate free radicals to initiate double bond polymerization to form a stable adhesive layer.

[0058] The first photoinitiator and the second photoinitiator respectively include one or more of benzoin diethyl ether (Omnirad 651), 1-hydroxycyclohexyl phenyl ketone (Irgacure 184), diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure 819), 2-methyl-4-methylthio-2-morpholinophenylpropionone (Irgacure 907), and 2-hydroxy-2methyl-1-phenylpropionone (Darocure 1173).

[0059] In some embodiments, the phosphorus-containing monomer is acrylic phosphorus-containing monomer PAM-200 and / or acrylic phosphorus-containing monomer PAM-300.

[0060] The present application adds a specific flame retardant Doher-601 into a UV-curing acrylic pressure-sensitive adhesive system. Under UV curing conditions, the flame retardant causes a photoinitiator in the system to absorb energy and decompose into ultra-highly active free radicals, which then initiates chemical internal crosslinking and branching reactions of phosphorus-containing monomers, flame retardants, monofunctional soft and hard monomers, monofunctional hard monomers, multifunctional monomers containing polymerizable double bonds, and functional monomers in the system. The flame retardant directly participates in the entire reaction system, and a bulk polymerized flame-retardant adhesive is obtained through chemical crosslinking modification, thereby achieving a relatively efficient flame retardant effect with a relatively low content of flame retardant. The UV-curing acrylic pressure-sensitive adhesive prepared by adopting the formula has the characteristics of high transparency, high peel strength, does not contain any organic solvents, and is environmentally friendly and energy-saving.

[0061] The present application improves the adhesive force of the pressure-sensitive adhesive by adding monofunctional acrylic soft monomers into the UV curing acrylic pressure-sensitive adhesive system. The long side chain alkyl groups of these monomers can weaken the interaction between the main chains of the polymer, achieve the internal plasticization effect, and reduce the glass transition temperature of the pressure-sensitive adhesive. At the same time, the introduction of acrylic functional monomers, the functional groups such as carboxyl, hydroxyl, and amine carried by these monomers themselves, under the action of intermolecular polar forces and hydrogen bonds, improve the cohesive strength and bonding strength of the pressure-sensitive adhesive.

[0062] like Figure 1 As shown, the second aspect of the present application provides a method for preparing the UV-curable acrylate pressure-sensitive adhesive provided in the first aspect, comprising the following steps:

[0063] S1. Evenly mix a monofunctional acrylate soft monomer, a monofunctional acrylate hard monomer, a portion of a multifunctional monomer containing at least two polymerizable double bonds, an acrylate functional monomer, a first photoinitiator, a phosphorus-containing monomer, and a portion of a flame retardant to prepare a mixture;

[0064] S2, irradiating the mixture with UV to obtain a prepolymer;

[0065] S3, compounding the prepolymer, the remaining flame retardant, the remaining multifunctional monomer containing at least two polymerizable double bonds and the second photoinitiator, and mixing them evenly to obtain a UV-curable acrylate pressure-sensitive adhesive.

[0066] In some embodiments, in step S2, a 1MW to 30MW ultraviolet lamp with a wavelength of 100nm to 400nm is used to irradiate the mixture to obtain a prepolymer.

[0067] The present application adopts a specific monofunctional acrylate soft monomer, a monofunctional acrylate hard monomer, a multifunctional monomer containing at least two polymerizable double bonds, an acrylate functional monomer, a first photoinitiator, a phosphorus-containing monomer, and a flame retardant Doher-601, and mixes them in a specific proportion, and then performs ultraviolet light reaction to prepare a prepolymer. Then, an appropriate proportion of the flame retardant Doher-601, a multifunctional monomer containing at least two polymerizable double bonds, and a second photoinitiator are added for compounding to obtain a pressure-sensitive adhesive product having both good flame retardancy and bonding properties.

[0068] Compared with traditional flame-retardant glue materials, the UV-curing acrylic pressure-sensitive adhesive prepared by the above-mentioned preparation method in this application does not need to be heated and cured in a high-temperature oven or other energy-consuming process. The preparation method has a simple process, short time consumption, high efficiency, low cost, no solvent, few volatile components, and is green and environmentally friendly.

[0069] The preparation method of the present application has no solvent contact throughout the process, is environmentally friendly and pollution-free, has no solvent volatilization, does not require recovery equipment, and has low cost.

[0070] The third aspect of the present application provides a pressure-sensitive adhesive film, which is prepared by the following preparation method:

[0071] The UV-curable acrylate pressure-sensitive adhesive provided in the first aspect or the UV-curable acrylate pressure-sensitive adhesive prepared according to the preparation method provided in the second aspect is coated on a release film substrate, and the release film is covered on the upper surface of the acrylate pressure-sensitive adhesive, and UV light curing treatment is performed to prepare a pressure-sensitive adhesive film.

[0072] In some embodiments, the coating gap is 100±2 um.

[0073] In some embodiments, the light source is a UV mercury lamp.

[0074] In some embodiments, the light intensity is 10 MW-50 MW, including but not limited to 10 MW, 20 MW, 30 MW, 40 MW, 50 MW.

[0075] In some embodiments, the illumination time is 300s-600s, including but not limited to 300s, 400s, 500s, and 600s.

[0076] In some embodiments, the total absorbed energy is 7200 mj / cm 2 -9600mj / cm 2 , including but not limited to 7200mj / cm 2 、8000mj / cm 2 、8200mj / cm 2 、8600mj / cm 2 、9000mj / cm 2 、9600mj / cm 2 .

[0077] In some embodiments, after the UV light curing treatment is completed, the desired pressure-sensitive adhesive film can be obtained by normally rolling it up and placing it for 24 hours.

[0078] It is understandable that the normal winding and placement time after the UV light curing treatment is completed in the present application is only an example, and as long as the required placement time of the pressure-sensitive adhesive film can be obtained, it is within the protection scope of the present application.

[0079] The present application will be further described below with reference to specific embodiments and comparative examples.

[0080] Example 1

[0081] Preparation of UV Curable Acrylic Pressure Sensitive Adhesive

[0082] S1. Add 64.7% of monofunctional acrylic soft monomer isooctyl acrylate, 15% of monofunctional acrylic hard monomers isooctyl methacrylate and isobornyl acrylate (the mass ratio of isooctyl methacrylate to isobornyl acrylate is 1:2), 2% of multifunctional monomer hexanediol diacrylate containing at least two polymerizable double bonds, 7% of acrylic functional monomer hydroxybutyl acrylate, 0.1% of the first photoinitiator 1-hydroxycyclohexyl phenyl ketone, 3% of phosphorus-containing monomer PAM-200 and 5% of flame retardant Doher-601 into a 2000 ml explosion-proof glass reactor after weighing, mix well and prepare a mixture.

[0083] S2. Irradiate the mixture with a 2MW ultraviolet lamp having a wavelength of 365nm to obtain a prepolymer.

[0084] S3. Add 0.1% of trimethylolpropane triacrylate, a multifunctional monomer containing at least two polymerizable double bonds, 0.1% of benzoin diethyl ether, a second photoinitiator, and 3% of flame retardant Doher-601 (the proportion of flame retardant in the system to the total mass is 8%) into the above prepolymer according to the mass proportion, mix well, and prepare UV-curing acrylate pressure-sensitive adhesive.

[0085] Preparation of pressure-sensitive adhesive film

[0086] The UV-curable acrylic pressure-sensitive adhesive prepared above was directly coated on a double-sided release PET release film substrate, covered with a single-sided PET release film, and cured by UV light. After curing, it was rolled up normally and placed for 24 hours to obtain a pressure-sensitive adhesive film. The coating gap was 100um, the light source was a UV mercury lamp, the light intensity was 20MW, the illumination time was 500s, and the total absorbed energy was 8600mj / cm 2 .

[0087] Example 2

[0088] Preparation of UV Curable Acrylic Pressure Sensitive Adhesive

[0089] S1. 63.65% of monofunctional acrylic soft monomers of isooctyl acrylate and n-butyl acrylate (the mass ratio of isooctyl acrylate and n-butyl acrylate is 1:1), 12% of monofunctional acrylic hard monomers of isooctyl methacrylate and isobornyl acrylate (the mass ratio of isooctyl methacrylate and isobornyl acrylate is 1:5), 1% of multifunctional monomer ethoxylated bisphenol A diacrylate containing at least two polymerizable double bonds, 5% of acrylic functional monomer hydroxyethyl acrylate, 0.1% of the first photoinitiator benzoin diethyl ether, 3% of phosphorus-containing monomer PAM-300, and 3% of flame retardant Doher-601 are weighed, added into a 2000 ml explosion-proof glass reactor, and mixed evenly to obtain a mixture.

[0090] S2. Irradiate the mixture with a 2MW ultraviolet lamp having a wavelength of 365nm to obtain a prepolymer.

[0091] S3. Add 0.15% of a multifunctional monomer hexanediol diacrylate containing at least two polymerizable double bonds, 0.1% of a second photoinitiator benzoin diethyl ether, and 12% of a flame retardant Doher-601 (the flame retardant accounts for 15% of the total mass in the system) into the above prepolymer according to the mass proportions, mix well, and prepare a UV-curing acrylate pressure-sensitive adhesive.

[0092] Preparation of pressure-sensitive adhesive film

[0093] The UV-curable acrylic pressure-sensitive adhesive prepared above was directly coated on a double-sided release PET release film substrate, covered with a single-sided PET release film, and cured by UV light. After curing, it was rolled up normally and placed for 24 hours to obtain a pressure-sensitive adhesive film. The coating gap was 100um, the light source was a UV mercury lamp, the light intensity was 20MW, the illumination time was 500s, and the total absorbed energy was 8600mj / cm 2 .

[0094] Example 3

[0095] Preparation of UV Curable Acrylic Pressure Sensitive Adhesive

[0096] S1. 64.63% of monofunctional acrylic soft monomers including isooctyl acrylate, n-butyl acrylate and lauryl acrylate (the mass ratio of isooctyl acrylate, n-butyl acrylate and lauryl acrylate is 3:2:2), 12% of monofunctional acrylic hard monomers including isooctyl methacrylate and isobornyl acrylate (the mass ratio of isooctyl methacrylate and isobornyl acrylate is 1:5), 2% of multifunctional monomer hexanediol diacrylate containing at least two polymerizable double bonds, 6% of acrylic functional monomer hydroxypropyl acrylate, 0.12% of the first photoinitiator diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, 5% of phosphorus-containing monomer PAM-300 and 5% of flame retardant Doher-601 are weighed, added into a 2000 ml explosion-proof glass reactor and mixed evenly to obtain a mixture.

[0097] S2. Irradiate the mixture with a 2MW ultraviolet lamp having a wavelength of 365nm to obtain a prepolymer.

[0098] S3. Add 0.15% of ethoxylated trimethylolpropane triacrylate, a multifunctional monomer containing at least two polymerizable double bonds, 0.1% of a second photoinitiator 2-hydroxy-2methyl-1-phenylacetone, and 5% of a flame retardant Doher-601 (the proportion of the flame retardant in the system to the total mass part is 10%) into the above-mentioned prepolymer according to the mass proportion, mix well, and prepare a UV-curing acrylate pressure-sensitive adhesive.

[0099] Preparation of pressure-sensitive adhesive film

[0100] The UV-curable acrylic pressure-sensitive adhesive prepared above was directly coated on a double-sided release PET release film substrate, covered with a single-sided PET release film, and cured by UV light. After curing, it was rolled up normally and placed for 24 hours to obtain a pressure-sensitive adhesive film. The coating gap was 100um, the light source was a UV mercury lamp, the light intensity was 20MW, the illumination time was 500s, and the total absorbed energy was 8600mj / cm 2 .

[0101] Example 4

[0102] Preparation of UV Curable Acrylic Pressure Sensitive Adhesive

[0103] S1. Add 64.7% of monofunctional acrylic soft monomer isooctyl acrylate, 15% of monofunctional acrylic hard monomers isooctyl methacrylate and isobornyl acrylate (the mass ratio of isooctyl methacrylate to isobornyl acrylate is 1:2), 2% of multifunctional monomer hexanediol diacrylate containing at least two polymerizable double bonds, 10% of acrylic functional monomer hydroxybutyl acrylate, 0.1% of the first photoinitiator 1-hydroxycyclohexyl phenyl ketone, 3% of phosphorus-containing monomer PAM-200 and 2% of flame retardant Doher-601 into a 2000 ml explosion-proof glass reactor after weighing, mix well and prepare a mixture.

[0104] S2. Irradiate the mixture with a 2MW ultraviolet lamp having a wavelength of 365nm to obtain a prepolymer.

[0105] S3. Add 0.1% of trimethylolpropane triacrylate, a multifunctional monomer containing at least two polymerizable double bonds, 0.1% of a second photoinitiator benzoin diethyl ether, and 3% of a flame retardant Doher-601 (the proportion of the flame retardant in the system to the total mass is 5%) into the above-mentioned prepolymer according to the mass proportion, mix well, and prepare a UV-curing acrylate pressure-sensitive adhesive.

[0106] Preparation of pressure-sensitive adhesive film

[0107] The UV-curable acrylic pressure-sensitive adhesive prepared above was directly coated on a double-sided release PET release film substrate, covered with a single-sided PET release film, and cured by UV light. After curing, it was rolled up normally and placed for 24 hours to obtain a pressure-sensitive adhesive film. The coating gap was 100um, the light source was a UV mercury lamp, the light intensity was 20MW, the illumination time was 500s, and the total absorbed energy was 8600mj / cm 2 .

[0108] Comparative Example 1

[0109] Preparation of solvent-based acrylic adhesive

[0110] Weigh 220 g of isooctyl acrylate, 220 g of butyl acrylate, 24 g of isobornyl methacrylate, 16 g of acrylic acid, 4 g of hydroxyethyl acrylate, 0.02 g of AMSD chain transfer agent, 1.5 g of initiator benzoyl peroxide, and 516 g of a 3:1 uniformly mixed solvent of ethyl acetate and toluene for use.

[0111] 100 g of isooctyl acrylate, 120 g of butyl acrylate, 10 g of isobornyl methacrylate, 8 g of acrylic acid, 1.5 g of hydroxyethyl acrylate, 0.02 g of AMSD chain transfer agent and 180 g of mixed solvent were put into a reactor and heated to 75°C.

[0112] 0.5 g of initiator benzoyl peroxide was dissolved in 20 g of mixed solvent to obtain an initiator solution. The initiator solution was added to the reactor and reacted at 75° C. for 120 min to obtain a prepolymer.

[0113] The remaining 120 g of isooctyl acrylate, 100 g of butyl acrylate, 14 g of isobornyl methacrylate, 8 g of acrylic acid, 2.5 g of hydroxyethyl acrylate, 0.5 g of initiator benzoyl peroxide and 200 g of mixed solvent were mixed evenly, and then added dropwise to the prepolymer for 80 min while maintaining the temperature at 80°C. After the addition was completed, the intermediate product A was obtained by keeping the temperature for 120 min.

[0114] The remaining initiator benzoyl peroxide (0.5 g) was added to the intermediate product A and the mixture was kept at 85° C. for 120 min to obtain the intermediate product B.

[0115] The remaining 116 g of the mixed solvent was added to the intermediate product B, kept at 85° C. for 60 min, and then cooled to below 40° C. to obtain an acrylate adhesive synthesized by a solvent method.

[0116] Add isocyanate curing agent LA-79 and flame retardant Doher-601 to the acrylic adhesive synthesized by the solvent method, stir evenly, and obtain the solvent-based acrylic adhesive with flame retardant properties required for coating. The mass ratio of acrylic adhesive to isocyanate curing agent LA-79 is 500:1; the mass ratio of acrylic adhesive to flame retardant Doher-601 is 5:2.

[0117] Preparation of acrylic adhesive film

[0118] The solvent-based acrylic adhesive is directly coated on the PET release film, and the solvent is dried in an oven to solidify into a pressure-sensitive adhesive film with good performance. The coating gap is 100um, and the 8-section oven temperature is set to 50℃ / 80℃ / 100℃ / 120℃ / 150℃ / 120℃ / 90℃ / 70℃. After high-temperature drying, the film is rolled up normally and placed for 24 hours to obtain an acrylic adhesive film.

[0119] Comparative Example 2

[0120] Preparation of emulsion acrylic adhesive

[0121] Weigh 220 g of isooctyl acrylate, 220 g of butyl acrylate, 28 g of styrene, 22 g of methyl methacrylate, 10 g of acrylic acid, 1 g of buffer sodium bicarbonate, 2 g of initiator ammonium persulfate, 5 g of anionic surfactant DNS-86 allyloxy sulfonate, 2.5 g of reactive surfactant COPS-1 sodium allyloxy hydroxypropyl sulfonate, and 450 g of deionized water for use.

[0122] 180 g of deionized water, 0.8 g of buffer sodium bicarbonate, 1 g of initiator ammonium persulfate, 5 g of anionic surfactant DNS-86 allyloxy sulfonate, and 2.5 g of reactive surfactant COPS-1 sodium allyloxyhydroxypropyl sulfonate were simultaneously put into a pre-emulsification kettle and dispersed with high-speed stirring for 30 min.

[0123] After the stirring is completed, add all the 220g of isooctyl acrylate, 220g of butyl acrylate, 28g of styrene, 22g of methyl methacrylate, and 10g of acrylic acid into the pre-emulsification kettle and stir at high speed while adding. After the addition is completed, continue to stir and disperse at high speed for 30 minutes to perform the pre-emulsification operation. After the emulsification is completed, let it stand without stratification to obtain a pre-emulsion liquid for standby use.

[0124] The remaining buffer 0.2 g of sodium bicarbonate and 220 g of deionized water were added into the reactor at the same time as a bottom liquid, and low-speed stirring was started and the mixture was heated to 85°C.

[0125] Dissolve the remaining initiator ammonium persulfate 1g with the remaining deionized water 50g. At the same time, drop the pre-emulsion and initiator ammonium persulfate into the reactor. The pre-emulsion drop time is 180min, and the initiator drop time is 210min. During the drop addition process, keep the temperature in the reactor at 85℃. After the drop addition is completed, keep the temperature for 60min.

[0126] After the insulation was completed, the system was cooled to 70° C., and 0.5 g of bleaching powder and 0.5 g of tert-butyl hydroperoxide were added for post-elimination reaction, and the temperature was kept for 30 minutes.

[0127] After the insulation is completed, the system is cooled to below 40° C., 14% ammonia water is added to adjust the pH to 7-8, and the discharged material is filtered to obtain the acrylic ester glue synthesized by the emulsion method.

[0128] Add aziridine crosslinking agent SAC-100 and flame retardant Doher-601 to the acrylic adhesive synthesized by the emulsion method, stir evenly, and prepare an emulsion acrylic adhesive. The mass ratio of acrylic adhesive to aziridine crosslinking agent SAC-100 is 1000:1; the mass ratio of acrylic adhesive to flame retardant Doher-601 is 5:2.

[0129] Preparation of acrylic adhesive film

[0130] The emulsion type acrylic adhesive is directly coated on the base material PET release film, dried in an oven to cure into a pressure-sensitive adhesive film with good performance. The coating gap is 100um, and the temperature of the 8-section oven is set to 50℃ / 80℃ / 100℃ / 120℃ / 150℃ / 120℃ / 90℃ / 70℃. After high-temperature drying, it is rolled up normally and placed for 24 hours to obtain an acrylic adhesive film.

[0131] Comparative Example 3

[0132] Preparation of UV Curable Acrylic Pressure Sensitive Adhesive

[0133] S1. Add 64.7% of monofunctional acrylic soft monomer isooctyl acrylate, 15% of monofunctional acrylic hard monomers isooctyl methacrylate and isobornyl acrylate (the mass ratio of isooctyl methacrylate to isobornyl acrylate is 1:2), 2% of multifunctional monomer hexanediol diacrylate containing at least two polymerizable double bonds, 7% of acrylic functional monomer hydroxybutyl acrylate, 0.1% of the first photoinitiator 1-hydroxycyclohexyl phenyl ketone, 3% of phosphorus-containing monomer PAM-200, and 5% of flame retardant dimethyl methylphosphonate into a 2000 ml explosion-proof glass reactor and mix well to obtain a mixture.

[0134] S2. Irradiate the mixture with a 2MW ultraviolet lamp having a wavelength of 365nm to obtain a prepolymer.

[0135] S3. Add 0.1% of trimethylolpropane triacrylate, a multifunctional monomer containing at least two polymerizable double bonds, 0.1% of benzoin diethyl ether, a second photoinitiator, and 3% of dimethyl methylphosphonate, a flame retardant, according to the mass proportion, to the above prepolymer (the proportion of flame retardants in the system to the total mass proportion is 8%) for compounding and mixing evenly to obtain a UV-curing acrylate pressure-sensitive adhesive.

[0136] Preparation of pressure-sensitive adhesive film

[0137] The UV-curable acrylic pressure-sensitive adhesive prepared above was directly coated on a double-sided release PET release film substrate, covered with a single-sided PET release film, and cured by UV light. After curing, it was rolled up normally and placed for 24 hours to obtain a pressure-sensitive adhesive film. The coating gap was 100um, the light source was a UV mercury lamp, the light intensity was 20MW, the illumination time was 500s, and the total absorbed energy was 8600mj / cm 2 .

[0138] Comparative Example 4

[0139] Preparation of UV Curable Acrylic Pressure Sensitive Adhesive

[0140] S1. 55% of monofunctional acrylic soft monomers of isooctyl acrylate and n-butyl acrylate (the mass ratio of isooctyl acrylate and n-butyl acrylate is 1:1), 12% of monofunctional acrylic hard monomers of isooctyl methacrylate and isobornyl acrylate (the mass ratio of isooctyl methacrylate and isobornyl acrylate is 1:5), 1% of multifunctional monomer ethoxylated bisphenol A diacrylate containing at least two polymerizable double bonds, 4.65% of acrylic functional monomer hydroxyethyl acrylate, 0.1% of the first photoinitiator benzoin diethyl ether, 2% of phosphorus-containing monomer PAM-300, and 5% of flame retardant Doher-601 are weighed, added into a 2000 ml explosion-proof glass reactor, and mixed evenly to obtain a mixture.

[0141] S2. Irradiate the mixture with a 2MW ultraviolet lamp having a wavelength of 365nm to obtain a prepolymer.

[0142] S3. Add 0.15% of a multifunctional monomer hexanediol diacrylate containing at least two polymerizable double bonds, 0.1% of a second photoinitiator benzoin diethyl ether, and 20% of a flame retardant Doher-601 (the flame retardant accounts for 25% of the total mass in the system) into the above prepolymer in proportion by mass, mix well, and prepare a UV-curing acrylate pressure-sensitive adhesive.

[0143] Preparation of pressure-sensitive adhesive film

[0144] The UV-curable acrylic pressure-sensitive adhesive prepared above was directly coated on a double-sided release PET release film substrate, covered with a single-sided PET release film, and cured by UV light. After curing, it was rolled up normally and placed for 24 hours to obtain a pressure-sensitive adhesive film. The coating gap was 100um, the light source was a UV mercury lamp, the light intensity was 20MW, the illumination time was 500s, and the total absorbed energy was 8600mj / cm 2 .

[0145] Test Case

[0146] The films prepared in the above examples and comparative examples were tested. The test results are shown in Table 1 below.

[0147] (1) Thickness test: Tested according to ASTM D3652 method.

[0148] (2) Peel strength test: Test the 180° peel strength according to GB / T2792 method.

[0149] (3) Light transmittance test: Tested according to GB2410-80 method.

[0150] (4) High temperature adhesion test: Tested according to GB / T4851-1998 method.

[0151] (5) Tensile length and elongation at break test: Tested according to GB / T1040 method.

[0152] (6) Flame retardant performance test: Tested according to ANST / UL94 2006 method.

[0153] Table 1

[0154]

[0155] By comparing Examples 1-4 with Comparative Examples 1-2, it can be seen that when the flame retardant Doher-601 is applied to the UV curing reaction system in the present application, a chemical internal cross-linking reaction occurs between it and other substances in the system, and it directly participates in the entire reaction system. The bulk polymerized flame-retardant glue is obtained through chemical cross-linking modification, thereby achieving a relatively efficient flame retardant effect with a lower content of flame retardant.

[0156] Comparing Examples 1-4 with Comparative Examples 1-4, it can be seen that the light transmittance of the adhesive film prepared by adopting the technical solution of the present application reaches more than 88%. Compared with the comparative examples, it has better surface properties and is more widely used.

[0157] By comparing Examples 1-4 with Comparative Example 3, it can be seen that the flame retardant Doher-601 of the present application undergoes a chemical internal cross-linking reaction with other substances in the system during UV curing, so the flame retardant products obtained are significantly better than those prepared by the conventional additive flame retardant dimethyl methylphosphonate in various performance indicators tested.

[0158] By comparing Examples 1-4 with Comparative Example 4, it can be seen that the flame retardant film prepared by adopting the technical solution of the present application has more advantages in mechanical properties, optical properties, elongation at break, etc. than the comparative example.

[0159] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above 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.

[0160] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A UV curing acrylate pressure sensitive adhesive, characterized in that: In terms of mass percentage, it includes the following raw materials: Monofunctional acrylic soft monomer: 55% to 75%; Monofunctional acrylic hard monomer: 12% to 20%; Multifunctional monomers containing at least two polymerizable double bonds: 1% to 5%; Acrylate functional monomer: 1% to 10%; First photoinitiator: 0.01% to 1%; Second photoinitiator: 0.01% to 1%; Phosphorus-containing monomers: 1% to 5%; Flame retardant Doher-601: 5%~15%.

2. The UV curing acrylate pressure sensitive adhesive according to claim 1, characterized in that: The monofunctional acrylic soft monomer includes one or more of n-butyl acrylate, isooctyl acrylate, lauryl acrylate, and caprolactone acrylate.

3. The UV curing acrylate pressure sensitive adhesive according to claim 1, characterized in that: The monofunctional acrylic ester hard monomer includes one or more of isobornyl acrylate, isobornyl methacrylate, isooctyl methacrylate, acryloylmorpholine, methyl acrylate, and methyl methacrylate.

4. The UV curing acrylate pressure sensitive adhesive according to claim 1, characterized in that: The multifunctional monomer containing at least two polymerizable double bonds includes one or more of hexanediol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, and propoxylated glycerol triacrylate.

5. The UV curable acrylate pressure sensitive adhesive according to claim 1, characterized in that: The acrylic acid ester functional monomer includes one or more of acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, acrylamide, and glycidyl acrylate.

6. The UV curing acrylate pressure sensitive adhesive according to claim 1, characterized in that: The first photoinitiator and the second photoinitiator respectively include one or more of benzoin diethyl ether, 1-hydroxycyclohexyl phenyl ketone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, 2-methyl-4-methylthio-2-morpholinepropiophenone, and 2-hydroxy-2methyl-1-phenylpropiophenone.

7. The UV curable acrylate pressure sensitive adhesive according to any one of claims 1 to 6, characterized in that: The phosphorus-containing monomer is acrylic acid type phosphorus-containing monomer PAM-200 and / or acrylic acid type phosphorus-containing monomer PAM-300.

8. A method for preparing a UV-curable acrylate pressure-sensitive adhesive as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Evenly mix a monofunctional acrylate soft monomer, a monofunctional acrylate hard monomer, a portion of a multifunctional monomer containing at least two polymerizable double bonds, an acrylate functional monomer, a first photoinitiator, a phosphorus-containing monomer, and a portion of a flame retardant to prepare a mixture; S2, irradiating the mixture with UV to obtain a prepolymer; S3, compounding the prepolymer, the remaining flame retardant, the remaining multifunctional monomer containing at least two polymerizable double bonds and the second photoinitiator, and mixing them evenly to obtain a UV-curable acrylate pressure-sensitive adhesive.

9. The preparation method according to claim 8, characterized in that: In step S2, a 1MW to 30MW ultraviolet lamp with a wavelength of 100nm to 400nm is used to irradiate the mixture.

10. A pressure-sensitive adhesive film, characterized in that: It is prepared by the following preparation method: The UV-curable acrylate pressure-sensitive adhesive according to any one of claims 1 to 7 or the UV-curable acrylate pressure-sensitive adhesive prepared by the preparation method according to claim 8 or 9 is coated on a release film substrate, and the release film is covered on the upper surface of the acrylate pressure-sensitive adhesive, and subjected to UV light curing treatment to obtain a pressure-sensitive adhesive film.

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