Vegetable oil-based acrylate prepolymer, UV adhesive as well as preparation method and application of vegetable oil-based acrylate prepolymer and UV adhesive

Abstract

The invention discloses a vegetable oil-based acrylate prepolymer, a UV (ultraviolet) adhesive as well as a preparation method and application of the vegetable oil-based acrylate prepolymer and the UV adhesive. The preparation method comprises the following steps: uniformly mixing raw materials including vegetable oil-based unsaturated coester, a diacrylate monomer and an initiator under a dark condition, and heating to react to generate the vegetable oil-based acrylate prepolymer. Raw materials including a monomer, a photoinitiator, a vegetable oil-based acrylate prepolymer, a coupling agent and an auxiliary agent are subjected to a dark reaction in vacuum, and the vegetable oil-based acrylate UV adhesive is prepared. The invention provides the plant oil-based acrylate prepolymer, the plant oil-based acrylate prepolymer is applied to the adhesive, a plant oil-based photocuring adhesive system with high adhesive strength and excellent weather resistance is provided, and the adhesive has the advantages of good adhesion firmness, small volume shrinkage, good flexibility and chemical resistance, cheap and easily available raw materials, environmental protection and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives. Further, it relates to vegetable oil-based acrylate prepolymers, UV adhesives, and their preparation methods and applications. Background Art

[0002] Ultraviolet curing (i.e., UV curing) is a new type of green and environmentally friendly technology in which organic small molecules react and polymerize into high molecular materials under the initiation of ultraviolet light. Since it uses light energy as the energy source, produces no greenhouse gases, uses less solvent, and can be cured at room temperature without heating, with a fast curing speed, it has the "5E" advantages of being efficient, enabling, economical, energy-saving, and environmentally friendly, and is known as the new technology for the green industry in the 21st century. It has been widely used in industries such as printing, packaging, communication, and building materials. Among them, the research on acrylate adhesives is particularly active.

[0003] The composition of UV-curing adhesives usually includes acrylate functional monomers, low molecular polymers, photoinitiators, and other functional additives. Among them, the performance of the low molecular weight polymer (prepolymer) basically determines the main performance of the adhesive after curing. Generally speaking, when the prepolymer has a large molecular weight, the volume shrinkage during curing is small, and the curing speed is fast. However, a large molecular weight will cause an increase in the viscosity of the system, thus requiring more monomers for dilution. Therefore, the selection of prepolymers is an important part of the formulation design of vegetable oil-based acrylate UV adhesives. The raw materials for the preparation of traditional prepolymers mainly come from non-renewable petrochemical resources, which are likely to cause environmental pollution. Exploring and developing environmentally friendly raw materials for adhesives is the key to promoting the green and sustainable development of the adhesive industry and has become one of the research hotspots in the field of adhesives. Introducing natural renewable resources into the photo-curing adhesive material system and developing new UV-curing functional monomers and prepolymers using renewable resources have important social and economic significance.

[0004] The fatty acid chain structure in vegetable oil is easy to degrade and harmless to the environment, making it an ideal green raw material. However, natural vegetable oil has defects in terms of hydrolysis stability and low-temperature fluidity, making it difficult to be directly applied industrially. Chemically modifying functional groups such as carbon-carbon double bonds and carboxyl groups in its structure can greatly improve its performance. Tung oil is also known as "Chinese wood oil". China's annual output of tung oil is about 100,000 tons, making it the world's largest tung oil producer, accounting for 80% of the world's total output and 60% of international trade volume. The conjugated double bonds in tung oil can not only participate in photocuring but also serve as excellent modification sites, and are extremely likely to undergo DA reactions with dienophiles. Therefore, it is expected to modify tung oil and introduce it into the UV-curing material system to partially replace the raw materials in the fossil resource route. Developing deep-processed products of tung oil trees, expanding the application scope of tung oil, and increasing the added value of tung oil are of great benefit to alleviating the energy crisis. Summary of the Invention

[0005] To solve the problems in the prior art, the present invention provides a vegetable oil-based acrylate prepolymer, a UV adhesive, and their preparation methods and applications. The present invention chemically modifies tung oil and further prepares a tung oil-based acrylate prepolymer, which is applied to adhesives. By controlling the addition amounts of the components of the adhesive, the prepared tung oil-based UV-curing adhesive has excellent mechanical properties and weather resistance. On the one hand, the product is easily degradable after being discarded, meeting the requirements of environmental friendliness; on the other hand, the introduction of biomass energy can also reduce industrial costs and realize the value-added utilization of biomass energy, having certain prospects for industrial application.

[0006] One of the objectives of the present invention is to provide a vegetable oil-based acrylate prepolymer copolymerized from raw materials including a vegetable oil-based unsaturated copolymer and a diacrylate monomer.

[0007] The vegetable oil-based acrylate prepolymer of the present invention is a mixture with different structures and molecular weights; its viscosity ranges from 5000 to 50000 cps. However, due to its overly complex structure, it is impossible to perform nuclear magnetic resonance characterization to solve the structure, nor is it easy to clarify its specific composition.

[0008] Another objective of the present invention is to provide a preparation method for a vegetable oil-based acrylate prepolymer, including the following steps:

[0009] Mix the raw materials including a vegetable oil-based unsaturated copolymer, a diacrylate monomer, and an initiator evenly in the dark and then heat and react to generate the vegetable oil-based acrylate prepolymer;

[0010] Preferably, it is used to prepare the vegetable oil-based acrylate prepolymer described in one of the objectives of the present invention.

[0011] In the preparation method of the vegetable oil-based acrylate prepolymer of the present invention, preferably,

[0012] The vegetable oil-based unsaturated co-ester is selected from at least one of a tetra-functionalized tung oil-based unsaturated co-ester and a tri-functionalized tung oil-based unsaturated co-ester;

[0013] The structure of the tetra-functionalized tung oil-based unsaturated co-ester (TMPG) is:

[0014]

[0015] The structure of the tri-functionalized tung oil-based unsaturated co-ester (TOAH) is

[0016]

[0017] From the above structures, it can be seen that the vegetable oil-based unsaturated co-esters TOAH and TMPG of the present invention contain both maleate and acrylate carbon-carbon double bond structures; and / or,

[0018] The diacrylate monomer is selected from at least one of ethylene glycol diacrylate and bisphenol A diacrylate; and / or,

[0019] The initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptonitrile, benzoyl peroxide, tert-butyl benzoyl peroxide, and methyl ethyl ketone peroxide.

[0020] In the preparation method of the vegetable oil-based acrylate prepolymer of the present invention, preferably,

[0021] Based on the total weight of the raw materials being 100%,

[0022] The addition amount of the vegetable oil-based unsaturated co-ester is 60 wt% to 74 wt%;

[0023] The addition amount of the diacrylate monomer is 25 wt% to 35 wt%;

[0024] The addition amount of the initiator is 1 wt% to 5 wt%;

[0025] Preferably,

[0026] The addition amount of the vegetable oil-based unsaturated co-ester is 65 wt% to 70 wt%;

[0027] The addition amount of the diacrylate monomer is 28 wt% to 32 wt%;

[0028] The addition amount of the initiator is 1 wt% to 3 wt%; and / or,

[0029] The temperature of the heating reaction is 40 to 70 °C; and / or,

[0030] The time of the heating reaction is 0.5 h to 3 h.

[0031] A third object of the present invention is to provide a vegetable oil-based acrylate UV adhesive, which comprises a monomer, a photoinitiator, a vegetable oil-based acrylate prepolymer, a coupling agent and an auxiliary agent; the vegetable oil-based acrylate prepolymer is selected from the vegetable oil-based acrylate prepolymer described in one of the objects of the present invention or the vegetable oil-based acrylate prepolymer obtained by the preparation method described in any one of Objects 2 to 4 of the second object of the present invention;

[0032] The monomer is selected from at least one of acrylic monomers and acrylate monomers.

[0033] In the UV adhesive containing a vegetable oil-based acrylate according to the present invention, preferably,

[0034] In the UV adhesive, by weight:

[0035]

[0036] In the UV adhesive containing a vegetable oil-based acrylate according to the present invention, preferably,

[0037] The acrylic monomer is selected from at least one of acrylic acid and methacrylic acid; and / or,

[0038] The acrylate monomer is selected from at least one of isobornyl acrylate, isobornyl methacrylate, methyl acrylate, ethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, trifluoroethyl methacrylate, isooctyl methacrylate, 2-hydroxypropyl acrylate, glycidyl acrylate, and glycidyl methacrylate.

[0039] In the UV adhesive containing a vegetable oil-based acrylate according to the present invention, preferably,

[0040] The photoinitiator is selected from at least one of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, diphenylglyoxal, diethylaminodiphenylglyoxal, diphenylacetone sulfonate, dialkoxyacetophenone, α-hydroxyalkylphenone, α-aminoketone compounds, benzophenone, and thioxanthone; preferably, the α-aminoketone compounds are selected from at least one of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone.

[0041] In the UV adhesive containing a vegetable oil-based acrylate according to the present invention, preferably,

[0042] The coupling agent is selected from silane coupling agents;

[0043] Preferably, the coupling agent is selected from trialkoxysilane coupling agents; more preferably, the coupling agent is selected from at least one of phenyltrimethoxysilane, phenyltriethoxysilane, γ-mercaptopropyltriethoxysilane, methyltriethoxysilane, and γ-aminopropyltriethoxysilane.

[0044] In the UV adhesive containing vegetable oil-based acrylate according to the present invention, preferably,

[0045] The auxiliary agent is selected from at least one of co-initiators, stabilizers, and inhibitors; preferably,

[0046] The co-initiator is selected from at least one of isooctyl p-dimethylaminobenzoate, diethanolamine, and triethanolamine; and / or,

[0047] The stabilizer is selected from at least one of borate esters and organic acids; and / or,

[0048] The inhibitor is selected from at least one of hydroquinone, tert-butylcatechol, p-methoxyphenol, and benzoquinone;

[0049] More preferably, the stabilizer is selected from at least one of trimethyl borate, triethyl borate, tri-n-propyl borate, triisopropyl borate, tri-o-tolyl borate, tri-m-tolyl borate, barbituric acid, salicylic acid, lauric acid, fumaric acid, and benzoic acid.

[0050] The fourth object of the present invention is to provide a method for preparing a UV adhesive containing vegetable oil-based acrylate according to any one of the third objects of the present invention, comprising the following steps:

[0051] Reacting raw materials including monomers, photoinitiators, vegetable oil-based acrylate prepolymers, coupling agents, and auxiliary agents in the dark under vacuum to obtain a vegetable oil-based acrylate UV adhesive.

[0052] In the method for preparing a UV adhesive containing vegetable oil-based acrylate according to the present invention, preferably,

[0053] First, add raw materials including monomers, vegetable oil-based acrylate prepolymers, coupling agents, stabilizers, and inhibitors, mix them, and then add photoinitiators and co-initiators to react in the dark under vacuum stirring conditions;

[0054] Preferably,

[0055] The vacuum degree of the dark reaction is -0.1 MPa to -0.01 MPa; and / or,

[0056] The time of the dark reaction is 1 to 2 hours; and / or,

[0057] The temperature of the dark reaction is 20 to 40 °C; and / or,

[0058] The stirring speed is 400 - 600 revolutions per minute.

[0059] The fifth object of the present invention is to provide an application of the UV adhesive containing vegetable oil-based acrylate according to any one of the third objects of the present invention in the bonding of optoelectronic devices, building materials, and medical materials.

[0060] The present invention utilizes the characteristics of the one-component acrylate UV curable adhesive system, which is convenient to operate, has strong adhesion, and is green and friendly. A biomass material, tung oil-based acrylate prepolymer, is introduced into the system. It has an interpenetrating network structure, which strengthens the wetting effect and chemical bond action of the adhesive, increases the internal force of the adhesive molecules, and has high adhesion strength after curing. The highly crosslinked network structure brings a low volume shrinkage rate, low water absorption rate, and good weather resistance. Combining vegetable oil and ultraviolet light curing technology to construct a "double green" application system for vegetable oil-based ultraviolet light curing materials can not only realize the deep development and effective utilization of vegetable oil products, expand the application fields of vegetable oil, reduce production costs, but also reduce the dependence on petrochemical resources, conform to the concept of green environmental protection and environmental friendliness, and help the green transformation of the polymer materials industry.

[0061] In the ranges and any values disclosed in the present invention, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein. In the following text, in principle, the various technical solutions can be combined with each other to obtain new technical solutions, which should also be regarded as specifically disclosed herein.

[0062] Compared with the prior art, the present invention has at least the following advantages:

[0063] The present invention provides a vegetable oil-based acrylate prepolymer and applies it to the adhesive, providing a vegetable oil-based photocuring adhesive system with high adhesion strength and good weather resistance. The adhesive has good adhesion firmness, small volume shrinkage, good flexibility and chemical resistance, and has the advantages of cheap and easily available raw materials, green environmental protection, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a schematic diagram of the preparation reaction of tetrafunctional tung oil-based unsaturated copolymer (TMPG);

[0065] Figure 2 It is a schematic diagram of the preparation reaction of trifunctional tung oil-based unsaturated copolymer (TOAH). DETAILED DESCRIPTION OF THE EMBODIMENTS

[0066] The present invention will be specifically described below in conjunction with specific embodiments. It is necessary to point out here that the following embodiments are only used for further illustration of the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0067] In addition, it should be noted that in the following specific embodiments, the various specific technical features described can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0068] In addition, any combination can be made between various different embodiments of the present invention as long as it does not violate the idea of the present invention. The technical solutions formed thereby belong to a part of the original public content of this specification and also fall within the protection scope of the present invention.

[0069] The present invention will be described in detail below through embodiments. All reagents used are commercially available. Room temperature refers to 25°C. All kinds of acrylate monomers and their synthetic reagents are purchased from InnoChem Co., Ltd.

[0070] In the embodiments of the present invention, the prepolymer is formed from raw materials including tetrafunctional tung oil-based unsaturated co-ester (TMPG), trifunctional tung oil-based unsaturated co-ester (TOAH), hexanediol diacrylate (HDDA), bisphenol A diacrylate (DDA), and an initiator in different formulations and ratios under the condition of slow heating. Among them, TMPG and TOAH are synthesized according to the methods reported in the literature. The specific steps are as follows:

[0071] 1. Preparation of tetrafunctional tung oil-based unsaturated co-ester (TMPG):

[0072] (1) Preparation of methyl eleostearate (ME): Put tung oil (50 g) into a flask equipped with a condenser and a stirrer, and heat it in a constant temperature water bath to 70°C. Then, slowly add a methanol solution containing 0.5 g of sodium hydroxide (12 g of methanol) and stir for 1 hour (300 rpm). Subsequently, adjust the pH value of the reaction system to the range of 6.5 - 7.0 with phosphoric acid (to neutralize the catalyst and have a demulsifying effect). Transfer the reaction solution to a separating funnel, collect the upper layer (methyl eleostearate ME), wash it with hot water 2 - 3 times, remove methanol by rotary evaporation, and add anhydrous calcium chloride for drying to obtain a relatively pure methyl eleostearate product for standby.

[0073] (2) Preparation of the adduct of methyl eleostearate and maleic anhydride (MEMA): Methyl eleostearate (ME, 100 g), maleic anhydride (MA, 34 g), aluminum chloride (AlCl 3, 1 g) and ethyl acetate (as a solvent, 50 g) were added to a flask, heated to 85 °C and reacted for 4 hours. After cooling to 40 °C, aluminum chloride was filtered off, ethyl acetate was removed by rotary evaporation, cyclohexane (100 mL) was added for washing, and the solid precipitate (unreacted maleic anhydride) was filtered. The product was transferred to a separatory funnel and allowed to stand, and the lower yellow liquid was collected (the upper layer was a light yellow cyclohexane solution of unreacted ME). The lower layer liquid was rotary evaporated to remove the residual solvent, and a dark yellow clear product (MEMA) was obtained for standby.

[0074] (3) Preparation of tetrafunctionalized tung oil-based unsaturated co-ester (TMPG): MEMA (30 g) and hydroquinone (0.275 g) were placed in a flask and heated. When the temperature reached 60 °C, N,N-dimethylethanolamine (0.825 g) was added. After stirring evenly, pentaerythritol triacrylate (PETA, 23 g) was slowly added dropwise, and then the mixture was raised to 80 °C. The addition process was completed within 5 min, and the temperature was further raised to 120 °C and reacted for 4 h and then cooled. When the temperature dropped to 60 °C, hydroquinone (0.320 g) was added. After the temperature was raised to 80 °C, N,N-dimethylethanolamine (0.320 g) and glycidyl methacrylate (GMA, 11 g) were added in sequence, and the reaction was carried out at 100 °C for 4 h to obtain a brown liquid tetrafunctionalized tung oil-based unsaturated co-ester (TMPG) for standby. The specific reaction process is as Figure 1 shown.

[0075] 2. Preparation of trifunctionalized tung oil-based unsaturated co-ester (TOAH):

[0076] (1) Preparation of tung oil-based triacrylate (TOAH): First, tung oil (30 g), KOH (10 g), water (10 ml) and ethanol (80 ml) were put into a flask equipped with a condenser and a stirrer, heated to 90 °C, and stirred for 30 minutes (300 rpm). After cooling, hydrochloric acid (5 mol / L) was added to adjust the pH of the system to 2 - 3. The crude product precipitate was dissolved in absolute ethanol, placed in the refrigerator overnight, and then ethanol and water were removed by rotary evaporation to obtain white crystal tung oil acid (TOA).

[0077] (2) Preparation of adduct of tung oil acid and maleic anhydride (tricarboxyl tung oil acid, TOTA): TOA (100 g), MA (35 g), aluminum chloride (1.00 g), and ethyl acetate (as a solvent, 50 g) were added to a flask, heated to 85 °C and reacted for 4 h. After cooling to 40 °C, aluminum chloride was filtered off, and ethyl acetate was removed by rotary evaporation. Water (100 g) and sodium hydroxide (30 g) were added to the flask. After heating to 75 °C, the crude product obtained from the above reaction was added, and the reaction was continued for 2.5 hours. Hydrochloric acid (5 mol / L) was used to adjust the pH of the system to 2 - 3, ethyl acetate (50 g) was added for extraction, washed with distilled water until neutral, and water and ethyl acetate were removed by rotary evaporation to obtain tung oil tricarboxylic acid (TOTA).

[0078] (3) Preparation of trifunctionalized tung oil-based unsaturated co-ester (TOAH): Add TOTA (10 g) and cyclohexane (10 g) into a flask. After heating to 55 °C, slowly add a solution of 2-hydroxyethyl acrylate (HEA, 11.00 g) containing 0.4 g of p-toluenesulfonic acid dropwise using a dropping funnel. Then, introduce nitrogen gas into the system, raise the temperature to 120 °C, react for 5 hours, add ethyl acetate (50 g) to dissolve, transfer to a separating funnel, and wash three times with saturated brine and distilled water respectively. After obtaining the upper clear liquid, dry it with anhydrous magnesium sulfate overnight, and rotary evaporate the filtered solution to remove the solvents (cyclohexane and ethyl acetate) to obtain the product trifunctionalized tung oil-based unsaturated co-ester (TOAH) for standby. The specific reaction process is as Figure 2 shown.

[0079] Preparation Example 1

[0080] Preparation of vegetable oil-based acrylate prepolymer:

[0081] Add 34 parts of TOAH, 34 parts of TMPG, and 30 parts of HDDA into a reactor for mixing, then add 2 parts of azobisisobutyronitrile (AIBN), stir (300 rpm) for 2 hours in the dark until homogeneous, slowly heat to 60 °C, and continue for 3 hours to obtain a viscous liquid for discharging to obtain prepolymer 1.

[0082] Preparation Example 2

[0083] Preparation of vegetable oil-based acrylate prepolymer:

[0084] Add 68 parts of TOAH and 30 parts of HDDA into a reactor for mixing, then add 2 parts of azobisisobutyronitrile (AIBN), stir (300 rpm) for 1 hour in the dark until homogeneous, slowly heat to 60 °C, and continue for 3 hours to obtain a viscous liquid for discharging to obtain prepolymer 2.

[0085] Preparation Example 3

[0086] Preparation of vegetable oil-based acrylate prepolymer:

[0087] Add 48 parts of TOAH, 20 parts of TMPG, and 30 parts of DDA into a reactor for mixing, then add 2 parts of tert-butyl peroxybenzoate, stir (300 rpm) for 2 hours in the dark until homogeneous, slowly heat to 55 °C, and continue for 2 hours to obtain a viscous liquid for discharging to obtain prepolymer 3.

[0088] Preparation Example 4

[0089] Preparation of vegetable oil-based acrylate prepolymer:

[0090] 41 parts of TOAH, 27 parts of TMPG, and 30 parts of DDA were added to a reactor for mixing. Then, 2 parts of methyl ethyl ketone peroxide were added, and the mixture was stirred (400 rpm) for 1 hour in the dark until homogeneous. It was slowly heated to 55 °C and maintained for 3 hours to obtain a viscous liquid, which was discharged to obtain prepolymer 4.

[0091] Preparation Example 5

[0092] Preparation of vegetable oil-based acrylate prepolymer:

[0093] 27 parts of TOAH, 41 parts of TMPG, and 30 parts of HDDA were added to a reactor for mixing. Then, 2 parts of azobisisoheptonitrile were added, and the mixture was stirred (400 rpm) for 2 hours in the dark until homogeneous. It was slowly heated to 60 °C and maintained for 2 hours to obtain a viscous liquid, which was discharged to obtain prepolymer 5.

[0094] Preparation Example 6

[0095] Preparation of vegetable oil-based acrylate prepolymer:

[0096] 20 parts of TOAH, 48 parts of TMPG, and 30 parts of HDDA were added to a reactor for mixing. Then, 2 parts of benzoyl peroxide were added, and the mixture was stirred (300 rpm) for 1 hour in the dark until homogeneous. It was slowly heated to 60 °C and maintained for 3 hours to obtain a viscous liquid, which was discharged to obtain prepolymer 6.

[0097] Preparation Example 7

[0098] Preparation of vegetable oil-based acrylate prepolymer:

[0099] 68 parts of TMPG and 30 parts of HDDA were added to a reactor for mixing. Then, 2 parts of azobisisobutyronitrile (AIBN) were added, and the mixture was stirred (300 rpm) for 1 hour in the dark until homogeneous. It was slowly heated to 60 °C and maintained for 3 hours to obtain a viscous liquid, which was discharged to obtain prepolymer 7.

[0100] Example 1

[0101] 100 parts of acrylate functional monomers (including 58 parts of isobornyl acrylate, 20 parts of 2-hydroxyethyl methacrylate (HEMA), 11 parts of isobornyl methacrylate, 7 parts of acrylic acid (AA), 4 parts of hydroxypropyl methacrylate (HPMA)), 38 parts of prepolymer 1, 1 part of coupling agent phenyltrimethoxysilane, 1 part of stabilizer trimethyl borate, and 1 part of inhibitor tert-butylcatechol were added to a reactor and mixed at a rotation speed of 300 revolutions per minute for 30 minutes until homogeneous. Then, 3 parts of photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 1 part of co-initiator 2-ethylhexyl 4-dimethylaminobenzoate were added. While maintaining a vacuum of -0.02 MPa, the mixture was mechanically stirred at a rotation speed of 400 revolutions per minute for 1 hour in the dark until homogeneous to obtain UV adhesive 1.

[0102] Example 2

[0103] 100 parts of acrylate functional monomers (including 56 parts of isobornyl acrylate, 24 parts of 2-hydroxyethyl methacrylate (HEMA), 9 parts of 2-ethylhexyl methacrylate (EHMA), 7 parts of methacrylic acid (MAA), 4 parts of hydroxypropyl methacrylate (HPMA)), 32 parts of prepolymer 2, 1 part of coupling agent phenyltrimethoxysilane, 2 parts of stabilizer triethyl borate, and 1 part of inhibitor hydroquinone were mixed in a reactor and mixed at a rotation speed of 300 revolutions per minute for 30 minutes until homogeneous. Then, 3 parts of photoinitiator benzoin methyl ether and 2 parts of co-initiator azobisisobutyronitrile were added. While maintaining a vacuum of -0.03 MPa, the mixture was mechanically stirred at a rotation speed of 500 revolutions per minute for 1 hour in the dark until homogeneous to obtain UV adhesive 2.

[0104] Example 3

[0105] 100 parts of acrylate functional monomers (including 51 parts of isobornyl acrylate, 23 parts of 2-hydroxyethyl methacrylate (HEMA), 12 parts of glycidyl acrylate (GA), 9 parts of acrylic acid (AA), 5 parts of hydroxypropyl acrylate (HPA)), 30 parts of prepolymer 3, 3 parts of coupling agent γ-mercaptopropyltriethoxysilane, 1 part of stabilizer tri-n-propyl borate, and 2 parts of inhibitor 4-methoxyphenol were mixed in a reactor and mixed at a rotation speed of 300 revolutions per minute for 30 minutes until homogeneous. Then, 2 parts of photoinitiator benzoin ethyl ether and 1 part of co-initiator diethanolamine were added. While maintaining a vacuum of -0.02 MPa, the mixture was mechanically stirred at a rotation speed of 600 revolutions per minute for 1 hour in the dark until homogeneous to obtain UV adhesive 3.

[0106] Example 4

[0107] 100 parts of acrylate functional monomers (including 53 parts of isobornyl methacrylate, 26 parts of hydroxypropyl acrylate HPA, 11 parts of acrylic acid AA, 6 parts of 2-ethylhexyl methacrylate EHMA, 4 parts of hydroxypropyl methacrylate HPMA), 28 parts of prepolymer 4, 3 parts of coupling agent methyltriethoxysilane, 1 part of stabilizer triisopropyl borate, and 1 part of inhibitor benzoquinone were mixed in a reactor and mixed at a speed of 300 revolutions per minute for 30 minutes until uniform. Then, 3 parts of photoinitiator diphenylglyoxal and 2 parts of co-initiator triethanolamine were added. Under the condition of a vacuum degree of -0.02 MPa and a speed of 400 revolutions per minute, mechanical stirring was carried out in the dark for 2 hours until uniform to obtain UV adhesive 4.

[0108] Example 5

[0109] 100 parts of acrylate functional monomers (including 48 parts of isobornyl methacrylate, 27 parts of glycidyl methacrylate GMA, 10 parts of methacrylic acid MAA, 8 parts of hydroxyethyl acrylate HEA, 7 parts of hydroxyethyl methacrylate HEMA), 28 parts of prepolymer 5, 2 parts of coupling agent γ-aminopropyltriethoxysilane, 2 parts of stabilizer barbituric acid, and 1 part of inhibitor tert-butylcatechol were mixed in a reactor and mixed at a speed of 300 revolutions per minute for 30 minutes until uniform. Then, 3 parts of photoinitiator dialkoxyacetophenone and 2 parts of co-initiator isooctyl p-dimethylaminobenzoate were added. Under the condition of a vacuum degree of -0.01 MPa and a speed of 500 revolutions per minute, mechanical stirring was carried out in the dark for 2 hours until uniform to obtain UV adhesive 5.

[0110] Example 6

[0111] 100 parts of acrylate functional monomers (including 50 parts of isobornyl methacrylate, 22 parts of hydroxypropyl acrylate HPA, 9 parts of acrylic acid AA, 13 parts of glycidyl acrylate GA, 6 parts of trifluoroethyl methacrylate TFEMA), 22 parts of prepolymer 6, 3 parts of coupling agent phenyltrimethoxysilane, 1 part of stabilizer lauric acid, and 1 part of inhibitor hydroquinone were mixed in a reactor and mixed at a speed of 300 revolutions per minute for 30 minutes until uniform. Then, 2 parts of photoinitiator α-hydroxyalkyl phenyl ketone and 2 parts of co-initiator triethanolamine were added. Under the condition of a vacuum degree of -0.03 MPa and a speed of 600 revolutions per minute, mechanical stirring was carried out in the dark for 2 hours until uniform to obtain UV adhesive 6.

[0112] Example 7

[0113] 100 parts of acrylate functional monomers (including 52 parts of isobornyl methacrylate, 22 parts of 2-hydroxyethyl acrylate (HEA), 13 parts of 2-ethylhexyl methacrylate (EHMA), 8 parts of methacrylic acid (MAA), and 5 parts of glycidyl methacrylate (GMA)), 20 parts of prepolymer 7, 1 part of coupling agent γ-aminopropyltriethoxysilane, 2 parts of stabilizer triethyl borate, and 1 part of inhibitor hydroquinone were mixed in a reactor and mixed at a speed of 300 revolutions per minute for 30 minutes until homogeneous. Then, 3 parts of photoinitiator benzoin ethyl ether and 2 parts of co-initiator triethanolamine were added. Under the condition of maintaining a vacuum degree of -0.03 MPa and a speed of 500 revolutions per minute, mechanical stirring was carried out in the dark for 1 hour until homogeneous to obtain UV adhesive 7.

[0114] Example 8

[0115] It adopted a scheme basically the same as that of Example 1, except that prepolymer 2 was used in the formula, and it was mixed and stirred until homogeneous by the same preparation method to obtain UV adhesive 8.

[0116] Example 9

[0117] It adopted a scheme basically the same as that of Example 1, except that prepolymer 7 was used in the formula, and it was mixed and stirred until homogeneous by the same preparation method to obtain UV adhesive 9.

[0118] Comparative Example 1

[0119] The formulation of Preparation Example 1 of a high-strength and high-stability UV bonding system was used, except that the prepolymer used in the formulation was an epoxy acrylate oligomer (Kayin Chemical HE 428, viscosity: 10000 - 25000 cps), and it was mixed and stirred until homogeneous by the same preparation method.

[0120] Performance test: The UV bonding systems described in the examples and Comparative Example 1 were tested as follows:

[0121] (1) Viscosity test method: Measured with a Brookfield-RVT type dial-type rotational viscometer at a test temperature of 25 °C and a condition of 20 rpm.

[0122] (2) Tensile strength test: The mechanical properties of the photocured film were measured using a UTM4204 type universal electronic testing machine in accordance with GB13022-91.

[0123] (3) Linear curing shrinkage rate test: Referring to the ISO 2577 measurement method, the length change of the fixed-length adhesive film before and after curing was measured, and the shrinkage rate was obtained by dividing the reduced value by the original value.

[0124] (4) Flexibility: The flexibility was tested according to the method described in the national standard GB / T 1731-1993 "Method for Determining the Flexibility of Paint Films".

[0125] (5) Water resistance: Water resistance is characterized by water absorption rate and tested according to the method of GB / T 1733-93.

[0126] (6) Chemical resistance: Prepare a film with a dry film thickness of 60 μm, place it in an oven at 100 °C and dry for 1 day, then soak it in 50% ethanol solution for 12 h, and observe whether the film turns white, softens, or becomes sticky. If it turns white, softens, or becomes sticky, it is abnormal.

[0127] The above tests are repeated three times and the average value is taken. The measurement results are shown in the following table.

[0128] Partial performance parameters of each example and comparative example

[0129]

[0130]

[0131] As can be seen from the above table, the viscosity, tensile strength, linear curing shrinkage rate, flexibility, water absorption rate, and chemical resistance performance parameters of each example are different, which is mainly related to the acrylate monomer formula, prepolymer type and content in each system; compared with the comparative example, the examples using vegetable oil-based acrylate prepolymers show greater adhesive strength, lower linear curing shrinkage rate, better flexibility, lower water absorption rate, and better chemical resistance. This is mainly because the cross-linked interpenetrating network structure is formed after the polymerization of the multi-functional tung oil-based unsaturated copolymer and acrylic monomers, which greatly increases the density and cross-linking degree of the adhesive system, enhances the internal molecular force, and thus has higher strength, lower shrinkage rate and water absorption rate, better stability, and better adhesion effect. The addition of vegetable oil-based prepolymers can improve the toughness of the system. Thanks to the flexibility of the tung oil structure, especially the long alkyl chain of the TOAH part, and TMPG can bring high strength and modulus to the system due to more cross-linkable sites. The two can play a synergistic role in the adhesive system, achieving a good balance between the rigidity and toughness of the system.

[0132] In summary, compared with the use of pure petroleum-based oligomers as prepolymers, the use of tung oil-based acrylate prepolymers in UV adhesives in the present invention can achieve comparable mechanical properties and functional characteristics such as high adhesive strength and low shrinkage rate. To a certain extent, it effectively replaces petroleum-based prepolymers for the preparation of adhesives, not only reducing costs but also improving the efficient utilization of vegetable oil as a biomass resource, meeting the green environmental protection requirements in the adhesive application field to a certain extent. Combining vegetable oil and ultraviolet curing technology to build a "double green" application system of vegetable oil-based ultraviolet curing materials can not only expand the application field of vegetable oil but also significantly reduce the use of petrochemical resources, contributing to the green transformation of the polymer materials industry.

[0133] The present invention has been described in detail in connection with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions of the present invention and their implementation manners, and all of these fall within the scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

[0134] All publications, patent applications, patents and other references mentioned in this specification are hereby incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0135] When this specification uses prefixes such as "known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by such prefixes cover those commonly used in the art at the time when this application is filed, but also include those that are not commonly used at present but will become recognized by the art as suitable for similar purposes.

[0136] In the context of this specification, any matter or thing not mentioned, except as expressly stated, shall directly apply those known in the art without any change.

Claims

1. A vegetable oil-based acrylate prepolymer, characterized in that: It is obtained by copolymerizing raw materials including vegetable oil-based unsaturated co-esters and diacrylate monomers.

2. A method for preparing a vegetable oil-based acrylate prepolymer, characterized in that: The following steps are involved: The raw materials including the vegetable oil-based unsaturated co-ester, the diacrylate monomer, and the initiator are mixed evenly under light-proof conditions and then heated to react to generate the vegetable oil-based acrylate prepolymer; It is preferably used to prepare the plant oil-based acrylate prepolymer described in claim 1.

3. The method for preparing the vegetable oil-based acrylate prepolymer according to claim 2, characterized in that: The vegetable oil-based unsaturated co-ester is selected from at least one of a tetrafunctional tung oil-based unsaturated co-ester and a trifunctional tung oil-based unsaturated co-ester; The structure of the tetrafunctional tung oil-based unsaturated co-ester is preferably: The structure of the trifunctional tung oil-based unsaturated co-ester is preferably: and / or, The diacrylate monomer is selected from at least one of hexylene glycol diacrylate and bisphenol A diacrylate; and / or, The initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, tert-butyl benzoyl peroxide, and methyl ethyl ketone peroxide.

4. The method for preparing the vegetable oil-based acrylate prepolymer according to claim 2, characterized in that: Taking the total weight of raw materials as 100%, The amount of vegetable oil-based unsaturated co-ester added is 60wt% to 74wt%; The amount of diacrylate monomer added is 25wt% to 35wt%; The amount of initiator added is 1wt% to 5wt%; Preferably, The amount of vegetable oil-based unsaturated co-ester added is 65wt% to 70wt%; The amount of diacrylate monomer added is 28wt% to 32wt%; The amount of the initiator added is 1 wt% to 3 wt%; and / or, The temperature of the heating reaction is 40 to 70°C; and / or, The heating reaction time is 0.5h to 3h.

5. A vegetable oil-based acrylate UV adhesive, characterized in that: The vegetable oil-based acrylate UV adhesive comprises monomers, photoinitiators, vegetable oil-based acrylate prepolymers, coupling agents and additives; The vegetable oil-based acrylate prepolymer is obtained by the preparation method as described in claim 1 or any one of claims 2 to 4; The monomer is selected from at least one of acrylic monomers and acrylate monomers.

6. The UV adhesive containing vegetable oil-based acrylate according to claim 5, characterized in that: In the UV adhesive, by weight:

7. The UV adhesive containing vegetable oil-based acrylate according to claim 5, characterized in that: The acrylic monomer is selected from at least one of acrylic acid and methacrylic acid; and / or, The acrylic acid ester monomer is selected from at least one of isobornyl acrylate, isobornyl methacrylate, methyl acrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, trifluoroethyl methacrylate, isooctyl methacrylate, hydroxypropyl acrylate, glycidyl acrylate, and glycidyl methacrylate.

8. The UV adhesive containing vegetable oil-based acrylate according to claim 5, characterized in that: The photoinitiator is selected from at least one of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, diphenylethanedione, diethylaminodiphenylethanedione, diphenylacetophenone sulfonate, dialkoxyacetophenone, α-hydroxyalkyl phenone, α-amino ketone compounds, benzophenone, and thioxanthone; preferably, the α-amino ketone compound is selected from at least one of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone.

9. The UV adhesive containing vegetable oil-based acrylate according to claim 5, characterized in that: The coupling agent is selected from silane coupling agents; Preferably, the coupling agent is selected from trialkoxysilane coupling agents; further preferably, the coupling agent is selected from at least one of phenyltrimethoxysilane, phenyltriethoxysilane, γ-mercaptopropyltriethoxysilane, methyltriethoxysilane, and γ-aminopropyltriethoxysilane.

10. The UV adhesive containing vegetable oil-based acrylate according to claim 5, characterized in that: The auxiliary agent is selected from at least one of a self-initiator, a stabilizer, and an inhibitor; preferably, The auxiliary initiator is selected from at least one of isooctyl p-dimethylaminobenzoate, azobisisobutyronitrile, diethanolamine and triethanolamine; and / or, The stabilizer is selected from at least one of boric acid ester and organic acid; and / or, The polymerization inhibitor is selected from at least one of hydroquinone, tert-butylcatechol, p-hydroxyanisole and benzoquinone; Further preferably, the stabilizer is selected from at least one of trimethyl borate, triethyl borate, tri-n-propyl borate, triisopropyl borate, tri-o-cresyl borate, tri-m-benzyl borate, barbituric acid, salicylic acid, lauric acid, fumaric acid and benzoic acid.

11. A method for preparing a UV adhesive containing vegetable oil-based acrylate according to any one of claims 5 to 10, characterized in that: The following steps are involved: Raw materials including monomers, photoinitiators, vegetable oil-based acrylate prepolymers, coupling agents and additives are reacted in a vacuum and in the dark to prepare a vegetable oil-based acrylate UV adhesive.

12. The method for preparing a UV adhesive containing vegetable oil-based acrylate according to claim 11, characterized in that: Firstly, raw materials including monomers, vegetable oil-based acrylate prepolymers, coupling agents, stabilizers and polymerization inhibitors are added and mixed, and then photoinitiators and co-initiators are added to react in the dark under vacuum stirring conditions; Preferably, The vacuum degree of the light-proof reaction is between -0.1MPa and -0.01MPa; The light-proof reaction time is 1 to 2 hours; and / or, The temperature of the light-proof reaction is 20 to 40°C; and / or, The stirring speed is 400-600 rpm.

13. Use of the UV adhesive containing vegetable oil-based acrylate according to any one of claims 5 to 10 in bonding optoelectronic devices, building materials, and medical materials.

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