Ultraviolet curable adhesive composition and method of making same

Abstract

The invention provides an ultraviolet curable adhesive composition and a preparation method thereof. The ultraviolet curable adhesive composition comprises, based on the total weight thereof: 20-35 wt% of a styrene-olefin block copolymer elastomer; 50 to 80 wt% of an acrylate monomer; 0.5 to 2.5 wt% of an acid-containing acrylic monomer; 0.01 to 2 wt% of a photoinitiator; and 0.01 to 2% by weight of a cross-linking agent. The bio-based carbon content of the ultraviolet-curable adhesive composition is greater than or equal to 60%, and the ultraviolet-curable adhesive composition is good in environmental protection property. In addition, the stripping adhesive force and the static shear force after curing are good, and the bonding requirements under different temperature and surface conditions can be met. Besides, the preparation method of the ultraviolet-curable adhesive composition is simple, the components are mixed and then coated, and the ultraviolet-curable adhesive composition can be cured after being irradiated by ultraviolet rays, so that the ultraviolet-curable adhesive composition is suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of adhesives, and specifically relates to a radiation-curable bio-based composition, in particular to an ultraviolet-curable adhesive composition and a preparation method thereof. Background Art

[0002] In the process of industrial development, adhesives, as important functional materials, are widely used in packaging, construction, electronics, automobiles and other fields. However, traditional adhesive products mostly rely on petroleum-derived raw materials, which not only leads to over-reliance on non-renewable resources, but also brings a series of problems such as greenhouse gas emissions and environmental pollution. As the world's emphasis on sustainable development continues to increase, the industrial demand for environmentally friendly materials is becoming increasingly urgent. The development of adhesives with high bio-based carbon content has become an important development direction for the industry. Bio-based materials, with their renewable and degradable properties, can effectively reduce dependence on petroleum resources and reduce greenhouse gas emissions, which is in line with the concept of green and environmentally friendly development. Therefore, how to increase the bio-based carbon content in the adhesive field has become a technical problem that needs to be solved urgently.

[0003] In addition, in the existing technology, increasing the bio-based carbon content of adhesives often faces a contradiction between performance. On the one hand, in order to meet environmental protection requirements, it is necessary to increase the proportion of bio-based raw materials as much as possible; on the other hand, the introduction of bio-based raw materials may have an adverse effect on the key properties of adhesives, such as peel adhesion and static shear force. For example, some studies have tried to use bio-based monomers, but due to the limitations of the structure or polymerization properties of the monomers, the cured adhesives cannot meet the actual application requirements in terms of bonding reliability. How to achieve a high bio-based carbon content while ensuring that the adhesive has good peel adhesion and static shear force has become one of the main challenges faced by those skilled in the art.

[0004] Currently, some existing bio-based adhesives have significant performance deficiencies. For example, certain bio-based epoxy resin compositions, despite having a high bio-based carbon content, exhibit poor peel adhesion and struggle to achieve strong bonds on a variety of surfaces. Furthermore, some biodegradable bio-based acrylate pressure-sensitive adhesives, while exhibiting some degradation resistance, exhibit insufficient static shear strength and are prone to bond failure under high temperatures or prolonged loads. These performance deficiencies limit the broader application of bio-based adhesives.

[0005] With the increasing environmental awareness of consumers and the advancement of corporate sustainable development strategies, more and more industries have put forward dual requirements for adhesives with high bio-based carbon content and excellent performance. For example, in the consumer goods field, especially in footwear manufacturing, adhesives are required to have not only high bio-based content to meet environmental certification requirements, but also good elasticity, damping performance and grip, including wet grip and stable performance over a wide temperature range. In high-end manufacturing fields such as electronics and automobiles, higher requirements are placed on the bonding reliability of adhesives, requiring them to maintain good peel adhesion and static shear force under different temperatures and surface conditions. However, there is a lack of bio-based adhesive products on the current market that can meet these requirements at the same time.

[0006] UV curing technology, with its advantages of fast curing, high production efficiency, low energy consumption, and minimal environmental pollution, is increasingly being used in the adhesive field. However, existing UV-curable adhesives are still mostly based on petroleum-based raw materials with low bio-based content. Combining high-biobased raw materials with UV curing technology to develop adhesives that are both environmentally friendly and exhibit fast curing properties has become a key research and development direction. UV curing technology can further improve production efficiency and reduce energy consumption while maintaining adhesive performance, aligning with the development trend of green manufacturing.

[0007] Therefore, it is of great significance to develop a UV-curable adhesive with high bio-based carbon content, good bonding performance and shear performance. Summary of the Invention

[0008] Based on the technical problems outlined above, the technical objective of this invention is to develop a UV-curable adhesive composition with a biobased carbon content greater than or equal to 60%, while exhibiting excellent peel adhesion and static shear strength, capable of meeting the performance requirements of general bonding applications under varying temperature and surface conditions. By rationally selecting raw materials such as biobased ethylenically unsaturated monomers and biobased block copolymers, and optimizing the formulation and preparation process, a balance between biobased content and performance is achieved, providing an environmentally friendly, high-performance solution for the adhesive industry.

[0009] The inventors of the present invention completed the present invention after intensive and careful research.

[0010] Specifically, according to one aspect of the present invention, there is provided a UV-curable adhesive composition, the UV-curable adhesive composition comprising, based on the total weight thereof:

[0011] 20-35 wt% of a styrene-olefin block copolymer elastomer;

[0012] 50-80% by weight of an acrylic acid ester monomer;

[0013] 0.5-2.5 wt% of an acid-containing acrylic monomer;

[0014] 0.01-2 wt% photoinitiator; and

[0015] 0.01-2 wt% of a cross-linking agent.

[0016] According to another aspect of the present invention, there is provided a method for preparing the ultraviolet curable adhesive composition as described above, the method comprising uniformly mixing the components.

[0017] Compared with the prior art in this field, the advantages of the present invention are:

[0018] 1. By introducing bio-based ethylenically unsaturated monomers (such as 2-octyl ...

[0019] 2. Through formulation design (such as the synergistic effect of bio-based monomers and block copolymers), the cured adhesive performs well in 180° peel strength tests and 70°C static shear tests, meeting the reliability requirements of general bonding applications under various temperatures and surface conditions.

[0020] 3. Clearly define the weight ratio of each component (e.g., 20-35% styrene-olefin block copolymer, 50-80% acrylate monomer, etc.), and optimize crosslinking density and polymerization efficiency by introducing additives such as acid-containing acrylic monomers, photoinitiators, and crosslinkers to further enhance mechanical properties;

[0021] 4. Adhesive preparation can be completed through the steps of solution preparation, mixing and degassing, coating and curing, without the need for complicated processes;

[0022] 5. Compared with traditional curing methods, UV curing is faster and consumes less energy, which can shorten the production cycle and avoid environmental pollution caused by solvent volatilization, meeting the needs of green manufacturing; and

[0023] 6. It has a wide range of application scenarios and is suitable for consumer goods (such as shoes), adhesives and other fields. It has advantages especially in scenarios that require high bio-based content. DETAILED DESCRIPTION

[0024] It should be understood that those skilled in the art can conceive of other various embodiments and can modify them according to the teachings of this specification without departing from the scope or spirit of the present disclosure. Therefore, the following specific embodiments are not intended to be limiting.

[0025] Unless otherwise indicated, all numbers used in the present specification and claims to indicate feature sizes, quantities, and physicochemical properties should be understood as being modified in all cases by the term "about". Therefore, unless otherwise indicated, the numerical parameters listed in the above description and the appended claims are approximate values, and those skilled in the art will be able to appropriately change these approximate values ​​by utilizing the teachings disclosed herein to seek to obtain the desired properties. The use of numerical ranges expressed as endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0026] As previously mentioned, the present invention addresses the technical challenge of developing adhesives that combine high bio-based carbon content with excellent performance. Specifically, it is necessary to increase the proportion of bio-based carbon in adhesives to address industry's demand for sustainable, environmentally friendly materials and reduce reliance on petroleum-derived raw materials. At the same time, while achieving high bio-based carbon content, the adhesive must also exhibit excellent peel adhesion and static shear strength, meeting the performance requirements of typical bonding applications under varying temperature and surface conditions.

[0027] Through systematic research, the inventors of the present invention discovered that by selecting bio-based acrylate monomers and block copolymers with high bio-based content (such as SF-902) as the main raw materials, through reasonable proportions (20-35% styrene-olefin block copolymer elastomer, 50-80% bio-based acrylate monomers, etc.), and adding auxiliary agents such as photoinitiators and cross-linking agents, and through mixing, degassing, UV curing and other processes, an adhesive composition with a bio-based carbon content of ≥60% and good peel adhesion and static shear force was prepared, thereby achieving a balance between environmental protection and performance.

[0028] Specifically, according to one aspect of the present invention, there is provided a UV-curable adhesive composition, the UV-curable adhesive composition comprising, based on the total weight thereof:

[0029] 20-35 wt% of a styrene-olefin block copolymer elastomer;

[0030] 50-80% by weight of an acrylic acid ester monomer;

[0031] 0.5-2.5 wt% of an acid-containing acrylic monomer;

[0032] 0.01-2 wt% photoinitiator; and

[0033] 0.01-2 wt% of a cross-linking agent.

[0034] Specifically, the present invention provides a UV-curable adhesive composition, which aims to solve the problem of difficult balance between bio-based carbon content and performance in bio-based adhesives in the prior art. By optimizing the raw material composition and preparation process, the synergistic improvement of high bio-based carbon content and excellent bonding performance is achieved.

[0035] The UV-curable adhesive composition of the present invention contains the following essential ingredients: 20-35% by weight of a styrene-olefin block copolymer elastomer; 50-80% by weight of an acrylate monomer; 0.5-2.5% by weight of an acid-containing acrylic monomer; 0.01-2% by weight of a photoinitiator; and 0.01-2% by weight of a crosslinker. These components are precisely proportioned to form a synergistic system: the styrene-olefin block copolymer elastomer provides the base viscosity and elastic backbone; the acrylate monomer forms a continuous phase upon polymerization, imparting adhesive properties; the acid-containing acrylic monomer improves crosslinking density and surface affinity through its carboxyl functional groups; the photoinitiator initiates polymerization under UV irradiation; and the crosslinker enhances the mechanical strength of the network structure through multifunctional reactions. This combination results in a composition with a bio-based carbon content of ≥60% while also exhibiting excellent peel adhesion and static shear strength.

[0036] According to certain preferred embodiments of the present invention, the elastomer is a styrene-biobased olefin block copolymer elastomer, wherein the number of repeating units derived from the bio-based olefin, based on the total number of repeating units of the styrene-biobased olefin block copolymer elastomer, is greater than or equal to 40%, and the number of repeating units derived from styrene is less than or equal to 40%. Further preferably, the number of repeating units derived from the bio-based olefin, based on the total number of repeating units of the styrene-biobased olefin block copolymer elastomer, is in the range of 45%-90%, and the number of repeating units derived from styrene is in the range of 10%-40%.

[0037] Preferably, the bio-based olefin is selected from one or more of the group consisting of farnesene, isoprene, limonene, myrcene, β-pinene, myrcene, sesquicitronellene, squalene, bio-based ethylene, bio-based propylene, bio-based 1,3-butadiene and bio-based butadiene. Preferably, the bio-based olefin is selected from natural olefins such as farnesene (such as α-farnesene, β-farnesene), isoprene, limonene, myrcene, β-pinene, myrcene, sesquicitronellene, squalene. Optionally, the bio-based olefin is selected from olefins prepared by biofermentation or plant extraction such as bio-based ethylene, bio-based propylene, bio-based 1,3-butadiene. Most preferably, the farnesene is one or more of α-farnesene and β-farnesene.

[0038] Regarding the styrene-olefin block copolymer elastomer used in this invention, Kuraray Co., Ltd.'s SF-902, a representative product in the SEPTON™ BIO-series, boasts up to 80% biobased content, resulting in a 33% reduction in greenhouse gas emissions compared to traditional SEBS and SEEPS materials. This elastomer not only provides a high biobased carbon source but also exhibits mechanical properties similar to or superior to those of traditional thermoplastic elastomers (TPEs), such as high elasticity, damping performance, and stability over a wide temperature range.

[0039] Preferably, the UV-curable adhesive composition comprises 23.0-30.9 wt % of the styrene-olefin block copolymer elastomer based on the total weight of the UV-curable adhesive composition. More preferably, the UV-curable adhesive composition comprises 24.2-26.4 wt % of the styrene-olefin block copolymer elastomer based on the total weight of the UV-curable adhesive composition.

[0040] According to certain preferred embodiments of the present invention, the acrylate monomer is a bio-based acrylate monomer. Preferably, the bio-based acrylate monomer is a bio-based acrylic acid C 8-18 The alkyl ester monomer is preferably one or more of the group consisting of 2-octyl acrylate (2-OA), 2-octyl acrylate (NOAA), lauryl acrylate (LA), 2-octadecyl acrylate (STA), and isobornyl acrylate (IBXA). Taking 2-octyl acrylate (2-OA) as an example, as a bio-based ethylenically unsaturated monomer, it not only participates in the polymerization reaction to form a polymer network structure, but also serves as a solvent to dissolve bio-based block copolymers (such as SF-902) and adjust the viscosity of the system. Bio-based acrylic acid C 8-18 The long-chain structure of the alkyl ester monomer gives the adhesive good flexibility and surface wettability, enabling it to achieve effective bonding on different substrate surfaces.

[0041] The total weight proportion of acrylic monomers in the composition ranges from 50-80% by weight, further optimized to 52.9-75.5% by weight, with an optimal range of 53.0-57.8% by weight. This ratio ensures that the monomers form a sufficient adhesion foundation after polymerization while providing space for the synergistic effects of other components.

[0042] According to certain preferred embodiments of the present invention, the acid-containing acrylic monomer is acrylic acid, methacrylic acid or a combination thereof, wherein the carboxyl functional group reacts with a crosslinking agent to increase the crosslinking density of the system and enhance the adhesion to polar substrates.

[0043] The acid-containing acrylic monomer preferably accounts for 0.5-2.5% by weight of the composition, with an optimal range of 0.8-2.2% and a most preferred range of 0.9-2.2%. This amount ensures sufficient functional groups for crosslinking while preventing excessive acidity from affecting polymerization stability.

[0044] According to the technical solution of the present invention, a synergistic effect exists between the acid-containing acrylic monomer and the crosslinking agent (such as HDDMA). The carboxyl groups react chemically with the ethylenically unsaturated groups of the crosslinker during UV curing, forming a denser network structure, thereby improving the adhesive's shear resistance and temperature resistance. Furthermore, the presence of the carboxyl groups improves the interfacial interaction between the adhesive and substrates such as metals and plastics, enhancing peel adhesion.

[0045] According to certain preferred embodiments of the present invention, the photoinitiator is selected from one or more of acetophenones (such as 2,2-dimethoxy-2-phenylacetophenone, Irg651) and benzoin ether photoinitiators, which decompose under 365nm ultraviolet light to generate free radicals, initiating the polymerization reaction of the acrylate monomer and the crosslinker.

[0046] The preferred weight percentage of photoinitiator in the composition is 0.01-2% by weight, with an optimized range of 0.05-0.27% by weight and a most preferred range of 0.17-0.27% by weight. This amount ensures sufficient initiation of the UV curing process while preventing residual photoinitiator from affecting the long-term stability of the adhesive.

[0047] According to certain preferred embodiments of the present invention, the crosslinker is a multifunctional ethylenically unsaturated monomer, optionally containing 3-6 ethylenically unsaturated groups, typically 1,6-hexanediol dimethacrylate (HDDMA). Preferably, the crosslinker comprises 0.01-2% by weight of the composition, with an optimized range of 0.05-0.11% and an optimal range of 0.06-0.11%. This multifunctional structure serves as a crosslinking point during polymerization, significantly improving the mechanical strength, solvent resistance, and temperature resistance of the adhesive.

[0048] According to certain preferred embodiments of the present invention, the UV-curable adhesive composition further comprises an unsaturated nitrogen-containing monomer. The unsaturated nitrogen-containing monomer is selected from one or more of an acrylamide-based unsaturated monomer (e.g., N,N-dimethylacrylamide, NN-DMAA), a caprolactam-based unsaturated monomer (e.g., N-vinylcaprolactam, NVC), a vinyl nitrogen-containing heterocyclic monomer (e.g., N-vinylpyrrolidone), and acrylonitrile.

[0049] Preferably, the unsaturated nitrogen-containing monomer is selected from one or more of an acrylamide-based unsaturated monomer, a caprolactam-based unsaturated monomer, a vinyl nitrogen-containing heterocyclic monomer, and acrylonitrile. Preferably, the acrylamide-based unsaturated monomer is selected from one or more of the group consisting of N,N-dimethylacrylamide, acrylamide, tert-butylacrylamide, dimethylaminoethylacrylamide, N-octylacrylamide, and 4-acryloylmorpholine; and / or the caprolactam-based unsaturated monomer is N-vinylcaprolactam; and / or the vinyl nitrogen-containing heterocyclic monomer is selected from one or more of the group consisting of N-vinylpyrrolidone, vinylmethyloxazolidinone, vinylimidazole, and vinylpyridine. Preferably, the unsaturated nitrogen-containing monomer is N,N-dimethylacrylamide, N-vinylcaprolactam, or a combination thereof.

[0050] The introduction of unsaturated nitrogen-containing monomers can adjust the polarity, glass transition temperature (Tg) and hydrogen bonding of the adhesive, thereby improving its bonding properties and cohesive strength at different temperatures.

[0051] According to some preferred embodiments of the present invention, the ultraviolet curable adhesive composition comprises 3-20% by weight of the unsaturated nitrogen-containing monomer based on its total weight. Preferably, when the unsaturated nitrogen-containing monomer includes the acrylamide unsaturated monomer, the ultraviolet curable adhesive composition comprises no more than 6.4% by weight of the acrylamide unsaturated monomer based on its total weight. Preferably, when the unsaturated nitrogen-containing monomer includes the caprolactam unsaturated monomer, the ultraviolet curable adhesive composition comprises no more than 18.8% by weight of the caprolactam unsaturated monomer based on its total weight. Preferably, the ultraviolet curable adhesive composition comprises 14.7-21.5% by weight of the unsaturated nitrogen-containing monomer based on its total weight, wherein the ultraviolet curable adhesive composition comprises 2.7-5.9% by weight of the acrylamide unsaturated monomer based on its total weight; and / or the ultraviolet curable adhesive composition comprises 8.8-18.8% by weight of the caprolactam unsaturated monomer based on its total weight.

[0052] Take N,N-dimethylacrylamide (NN-DMAA) and N-vinylcaprolactam (NVC) as examples: NN-DMAA enhances adhesion to polar substrates through its polar amide group, while NVC modulates the system's flexibility and temperature sensitivity through the ring-opening reaction of the caprolactam ring, maintaining stable bonding performance over a wide temperature range. The combination of these two can simultaneously improve peel adhesion and static shear strength.

[0053] According to certain preferred embodiments of the present invention, the UV-curable adhesive composition has a bio-based carbon content greater than or equal to 60%. According to certain preferred embodiments of the present invention, the bio-based carbon content of the overall composition reaches a level of ≥60% by precisely controlling the ratio of each bio-based component.

[0054] The calculation of bio-based carbon content as mentioned in the present invention is based on the method described in US2012288692A1. Specifically, the ASTM D6866-10 standard is used. 14 C analysis, by measuring the organic radiocarbon ( 14 The ratio of carbon to a modern reference standard (expressed as “pMC” or “percent modern carbon”) determines the proportion of biobased origin of the feedstock.

[0055] According to another aspect of the present invention, there is provided a method for preparing the ultraviolet curable adhesive composition as described above, the method comprising uniformly mixing the components.

[0056] Specifically, a styrene-olefin block copolymer elastomer, an acrylate monomer, an acid-containing acrylic monomer, a photoinitiator, and a crosslinking agent (and optionally an unsaturated nitrogen-containing monomer) are uniformly mixed according to the formula ratio. If a solid or high-viscosity block copolymer is used, it can be first dissolved in an acrylate monomer (such as 2-OA) to form a solution of a certain concentration. The mixed resin is then degassed in a vacuum chamber to remove bubbles in the system and prevent the formation of pores after curing.

[0057] The following detailed description is intended to illustrate the present disclosure by way of illustration and not limitation.

[0058] Specific embodiment 1 is a UV-curable adhesive composition, which comprises, based on the total weight of the UV-curable adhesive composition:

[0059] 20-35 wt% of a styrene-olefin block copolymer elastomer;

[0060] 50-80% by weight of an acrylic acid ester monomer;

[0061] 0.5-2.5 wt% of an acid-containing acrylic monomer;

[0062] 0.01-2 wt% photoinitiator; and

[0063] 0.01-2 wt% of a cross-linking agent.

[0064] Embodiment 2 is a UV-curable adhesive composition according to embodiment 1, wherein the styrene-olefin block copolymer elastomer is a styrene-bio-based olefin block copolymer elastomer.

[0065] Embodiment 3 is a UV-curable adhesive composition according to embodiment 2, wherein the number of repeating units derived from the bio-based olefin is greater than or equal to 40%, and the number of repeating units derived from the styrene is less than or equal to 40%, based on the total number of repeating units of the styrene-bio-based olefin block copolymer elastomer.

[0066] Embodiment 4 is a UV-curable adhesive composition according to embodiment 3, wherein the number of repeating units derived from the bio-based olefin is in the range of 45%-90%, and the number of repeating units derived from the styrene is in the range of 10%-40%, based on the total number of repeating units of the styrene-bio-based olefin block copolymer elastomer.

[0067] Embodiment 5 is a UV-curable adhesive composition according to embodiment 2, wherein the bio-based olefin is selected from one or more of the group consisting of farnesene, isoprene, limonene, myrcene, β-pinene, myrcene, sesquicitronellal, squalene, bio-based ethylene, bio-based propylene, bio-based 1,3-butadiene, and bio-based butadiene.

[0068] Embodiment 6 is the ultraviolet curable adhesive composition according to embodiment 5, wherein the farnesene is one or more of α-farnesene and β-farnesene.

[0069] Embodiment 7 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 23.0-30.9 wt % of the styrene-olefin block copolymer elastomer based on the total weight of the ultraviolet curable adhesive composition.

[0070] Embodiment 8 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 24.2-26.4 wt % of the styrene-olefin block copolymer elastomer based on the total weight of the ultraviolet curable adhesive composition.

[0071] Embodiment 9 is the UV-curable adhesive composition according to embodiment 1, wherein the acrylate monomer is a bio-based acrylate monomer.

[0072] Embodiment 10 is a UV-curable adhesive composition according to embodiment 9, wherein the bio-based acrylate monomer is bio-based acrylic acid C 8-18 Alkyl ester monomers.

[0073] Specific embodiment 11 is a UV-curable adhesive composition according to specific embodiment 10, wherein the bio-based acrylate monomer is selected from one or more of the group consisting of 2-octyl acrylate (2-OA), 2-octyl acrylate (NOAA), lauryl acrylate (LA), 2-octadecyl acrylate (STA) and isobornyl acrylate (IBXA).

[0074] Embodiment 12 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 52.9-75.5 wt % of the acrylate monomer based on the total weight of the ultraviolet curable adhesive composition.

[0075] Embodiment 13 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 53.0-57.8 wt % of the acrylate monomer based on the total weight of the ultraviolet curable adhesive composition.

[0076] Embodiment 14 is the UV-curable adhesive composition according to embodiment 1, wherein the acid-containing acrylic monomer is acrylic acid, methacrylic acid, or a combination thereof.

[0077] Embodiment 15 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 0.8-2.2 wt % of the acid-containing acrylic monomer based on the total weight of the ultraviolet curable adhesive composition.

[0078] Embodiment 16 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 0.9-2.2 wt % of the acid-containing acrylic monomer based on the total weight of the ultraviolet curable adhesive composition.

[0079] Specific embodiment 17 is the ultraviolet curable adhesive composition according to specific embodiment 1, wherein the photoinitiator is selected from one or more of acetophenone-based photoinitiators and benzoin ether-based photoinitiators.

[0080] Embodiment 18 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 0.05-0.27 wt % of the photoinitiator based on the total weight of the ultraviolet curable adhesive composition.

[0081] Embodiment 19 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 0.17-0.27 wt % of the photoinitiator based on the total weight of the ultraviolet curable adhesive composition.

[0082] Embodiment 20 is the UV-curable adhesive composition according to embodiment 1, wherein the crosslinking agent is a multifunctional ethylenically unsaturated monomer.

[0083] Embodiment 21 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the crosslinking agent is a multifunctional ethylenically unsaturated monomer containing 3 to 6 ethylenically unsaturated groups.

[0084] Embodiment 22 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 0.05-0.11 wt % of the crosslinking agent based on the total weight of the ultraviolet curable adhesive composition.

[0085] Embodiment 23 is the ultraviolet curable adhesive composition according to embodiment 1, wherein the ultraviolet curable adhesive composition comprises 0.06-0.11 wt % of the crosslinking agent based on the total weight of the ultraviolet curable adhesive composition.

[0086] Embodiment 24 is the UV-curable adhesive composition according to embodiment 1, further comprising an unsaturated nitrogen-containing monomer.

[0087] Specific embodiment 25 is a UV-curable adhesive composition according to specific embodiment 24, wherein the unsaturated nitrogen-containing monomer is selected from one or more of an acrylamide-based unsaturated monomer, a caprolactam-based unsaturated monomer, a vinyl nitrogen-containing heterocyclic monomer, and acrylonitrile.

[0088] Embodiment 26 is a UV-curable adhesive composition according to embodiment 25, wherein:

[0089] The acrylamide-based unsaturated monomer is one or more selected from the group consisting of N, N-dimethylacrylamide, acrylamide, tert-butylacrylamide, dimethylaminoethylacrylamide, N-octylacrylamide and 4-acryloylmorpholine; and / or

[0090] The caprolactam-based unsaturated monomer is N-vinylcaprolactam; and / or

[0091] The vinyl nitrogen-containing heterocyclic monomer is one or more selected from the group consisting of N-vinyl pyrrolidone, vinyl methyl oxazolidinone, vinyl imidazole and vinyl pyridine.

[0092] Embodiment 27 is a UV-curable adhesive composition according to embodiment 24, wherein the unsaturated nitrogen-containing monomer is N,N-dimethylacrylamide, N-vinylcaprolactam, or a combination thereof.

[0093] Embodiment 28 is the ultraviolet curable adhesive composition according to embodiment 25, wherein the ultraviolet curable adhesive composition comprises 3-20 wt % of the unsaturated nitrogen-containing monomer based on the total weight of the ultraviolet curable adhesive composition.

[0094] Embodiment 29 is a UV-curable adhesive composition according to embodiment 25, wherein when the unsaturated nitrogen-containing monomer includes the acrylamide-based unsaturated monomer, the UV-curable adhesive composition includes no more than 6.4 wt % of the acrylamide-based unsaturated monomer based on the total weight of the UV-curable adhesive composition.

[0095] Embodiment 30 is a UV-curable adhesive composition according to embodiment 25, wherein when the unsaturated nitrogen-containing monomer includes the caprolactam-based unsaturated monomer, the UV-curable adhesive composition includes no more than 18.8 wt % of the caprolactam-based unsaturated monomer based on the total weight of the UV-curable adhesive composition.

[0096] Embodiment 31 is the ultraviolet curable adhesive composition according to embodiment 25, wherein the ultraviolet curable adhesive composition comprises 14.7-21.5 wt % of the unsaturated nitrogen-containing monomer based on the total weight of the ultraviolet curable adhesive composition.

[0097] Embodiment 32 is a UV-curable adhesive composition according to embodiment 31, wherein:

[0098] The ultraviolet curable adhesive composition comprises 2.7-5.9 wt % of the acrylamide-based unsaturated monomer based on the total weight of the ultraviolet curable adhesive composition; and / or

[0099] The ultraviolet curable adhesive composition includes 8.8 to 18.8 wt % of the caprolactam-based unsaturated monomer based on the total weight of the composition.

[0100] Embodiment 33 is the UV-curable adhesive composition according to embodiment 1, wherein the UV-curable adhesive composition has a bio-based carbon content greater than or equal to 60%.

[0101] Specific embodiment 34 is a method for preparing the ultraviolet curable adhesive composition according to any one of specific embodiments 1 to 33, the method comprising uniformly mixing the components.

[0102] The present invention will be described in more detail below with reference to the examples. It should be noted that these descriptions and examples are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The scope of protection of the present invention shall be subject to the appended claims.

[0103] Example

[0104] In the present invention, unless otherwise specified, all reagents used were commercially available products and were used directly without further purification.

[0105] Table 1 below lists the raw material information used in the examples and comparative examples of the present invention.

[0106] Table 1 Information on raw materials used in the examples and comparative examples of the present invention

[0107]

[0108] Test Method

[0109] According to the methods described in detail below, the UV-curable adhesive compositions prepared in the following examples and comparative examples were subjected to peel adhesion performance tests and static shear performance tests, respectively.

[0110] Peel adhesion performance test

[0111] The test of peel adhesion performance was carried out according to ASTM D3330 / D3330M standard using 180° peel force test method. Specifically, a stainless steel plate (SS plate) was prepared, and the protective film on its surface was peeled off to expose a fresh surface. The adhesive prepared in each of the following embodiments and comparative examples was transferred to a PET release film respectively. Then, the adhesive sample on the PET release film was cut into 1 inch × 8 inch adhesive strips. Subsequently, the 1 inch × 8 inch adhesive strip was placed on the stainless steel plate and rolled back and forth with a 1 kg rubber roller 2 times to make the adhesive fit tightly with the stainless steel plate to prepare a test specimen. Then, 365 nm ultraviolet light was used with a total dose of 2000 mJ / cm 2 Radiation curing. The prepared test specimens were placed in an environment with a temperature of 23°C and 50% relative humidity for 30 minutes before peel testing. A 180° peel test was performed on the adhesive sample on a stainless steel plate using a tensile testing machine (Model: 34TM-5; Manufacturer: Instron) at a peel rate of 12 inches / minute. The force during the peeling process was recorded (unit: N / mm) to evaluate the adhesive's peel adhesion performance.

[0112] The evaluation criteria for conventional adhesive applications are as follows:

[0113] When the peel force value is greater than 0.60, it is evaluated as “excellent”;

[0114] When the data is greater than or equal to 0.5 and less than 0.6, the evaluation is “good”;

[0115] When the data is greater than or equal to 0.3 and less than 0.5, it is evaluated as "qualified"; and

[0116] When the data is less than 0.3, it is evaluated as "unqualified".

[0117] Static shear performance test

[0118] The static shear performance test was carried out according to the ASTM D3654 standard using the static shear force test method. Specifically, first, the stainless steel panel was cleaned with isopropyl alcohol (IPA). The adhesive prepared in each of the following examples and comparative examples was transferred to a PET release film. Then, the adhesive sample on the PET release film was cut into 1 inch × 1 inch adhesive strips. Subsequently, the 1 inch × 1 inch adhesive strips were laminated on the cleaned stainless steel panel to prepare a test specimen. Then, ultraviolet light of 365 nm was used at a total dose of 2000 mJ / cm 2 After irradiation curing, the test specimen was placed in a 70°C oven, a 1000-gram load was applied, and the time (in minutes) required for the weight to pull the adhesive away from the stainless steel plate was recorded. If no adhesive failure was observed after 10,000 minutes, it was recorded as "10,000 minutes" to evaluate the static shear performance of the adhesive.

[0119] The evaluation criteria for conventional adhesive applications are as follows:

[0120] When the static shear time value is greater than 1000 minutes, it is evaluated as “excellent”;

[0121] When the static shear time value is greater than or equal to 500 minutes and less than 1000 minutes, it is evaluated as "good";

[0122] When the static shear time value is greater than or equal to 100 minutes and less than 500 minutes, it is evaluated as "pass"; and

[0123] When the static shear time value was less than 100 minutes, it was evaluated as "unacceptable".

[0124] Example 1 (E1)

[0125] 23.0 g of styrene-olefin block copolymer elastomer SF902, 75.5 g of 2-octyl acrylate (2-OA), 1.2 g of acrylic acid (AA), 0.25 g of photoinitiator Irq651, and 0.08 g of 1,6-hexanediol dimethacrylate HDDMA (SR239) were stirred and dissolved at room temperature (23 ± 2°C). The mixture was then transferred to a vacuum degasser and degassed at a vacuum level of ≤ -0.09 MPa for 20 minutes to remove air bubbles from the mixture, thereby obtaining a UV-curable adhesive composition 1. The ratios of the raw materials used to prepare the UV-curable adhesive composition 1 in Example 1 are shown in Table 2 below.

[0126] Then, the UV curable adhesive composition 1 prepared in Example 1 was subjected to a peel adhesion performance test and a static shear performance test according to the peel adhesion performance test method and the static shear performance test method described in detail above, and the results are shown in Table 3 below.

[0127] Examples 2-32 (E2-E32) and Comparative Examples (CE1-CE3)

[0128] Ultraviolet curable adhesive compositions 2-32 and comparative ultraviolet curable adhesive compositions 1-3 were prepared in a similar manner to the above Example 1, except that the raw material ratios were changed as shown in Table 2 below.

[0129] Then, according to the peel adhesion performance test method and static shear performance test method described in detail above, the UV-curable adhesive compositions 2-32 and comparative UV-curable adhesive compositions 1-3 prepared in Examples 2-32 (E2-E32) and Comparative Examples (CE1-CE3) were subjected to peel adhesion performance tests and static shear performance tests, respectively, and the results are shown in Table 3 below.

[0130] Table 2 Ratios of raw materials for preparing UV-curable adhesive compositions in Examples 1-32 (E1-E32) and Comparative Examples (CE1-CE3)

[0131]

[0132]

[0133] Table 3 Performance test of the UV-curable adhesive compositions prepared in Examples 1-32 (E1-E32) and Comparative Examples (CE1-CE3)

[0134]

[0135]

[0136] As can be seen from the results shown in Table 3 above, when a combination of specific amounts of the styrene-olefin block copolymer elastomer, the acrylate monomer, the acid-containing acrylic monomer, the photoinitiator, and the crosslinker is selected within the scope of the present invention, an adhesive composition having a bio-based carbon content of ≥60% and good peel adhesion and static shear strength can be prepared.

[0137] In addition, by further optimizing the ratio of the components in the composition, excellent performance in both peel adhesion and static shear force can be achieved.

[0138] Although specific embodiments have been shown and described in the present invention, it will be understood by those skilled in the art that various alternative and / or equivalent embodiments may be used to replace the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to include any improvements or changes to the specific embodiments discussed in the present invention. It will be understood by those skilled in the art that various modifications and changes may be made without departing from the scope of the present invention. Such modifications and changes are intended to fall within the scope of the present invention as defined in the appended claims.

Claims

1. A UV-curable adhesive composition, comprising, based on the total weight of the UV-curable adhesive composition: 20-35 wt% of a styrene-olefin block copolymer elastomer; 50-80% by weight of an acrylic acid ester monomer; 0.5-2.5 wt% of an acid-containing acrylic monomer; 0.01-2 wt% photoinitiator; and 0.01-2 wt% of a cross-linking agent. 2 . The ultraviolet curable adhesive composition according to claim 1 , wherein the styrene-olefin block copolymer elastomer is a styrene-biobased olefin block copolymer elastomer.

3. The ultraviolet curable adhesive composition according to claim 2, wherein the number of repeating units derived from the bio-based olefin is greater than or equal to 40%, and the number of repeating units derived from the styrene is less than or equal to 40%, based on the total number of repeating units of the styrene-bio-based olefin block copolymer elastomer.

4. The ultraviolet curable adhesive composition according to claim 3, wherein the number of repeating units derived from the bio-based olefin is in the range of 45% to 90%, and the number of repeating units derived from the styrene is in the range of 10% to 40%, based on the total number of repeating units of the styrene-bio-based olefin block copolymer elastomer.

5. The ultraviolet-curable adhesive composition according to claim 2, wherein the bio-based olefin is one or more selected from the group consisting of farnesene, isoprene, limonene, myrcene, β-pinene, myrcene, sesquicitronellal, squalene, bio-based ethylene, bio-based propylene, bio-based 1,3-butadiene, and bio-based butadiene. The ultraviolet curable adhesive composition according to claim 5 , wherein the farnesene is one or more of α-farnesene and β-farnesene. 7 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 23.0 to 30.9 wt % of the styrene-olefin block copolymer elastomer based on the total weight of the ultraviolet curable adhesive composition. 8 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 24.2 to 26.4 wt % of the styrene-olefin block copolymer elastomer based on the total weight of the ultraviolet curable adhesive composition. 9 . The ultraviolet curable adhesive composition according to claim 1 , wherein the acrylate monomer is a bio-based acrylate monomer.

10. The ultraviolet curable adhesive composition according to claim 9, wherein the bio-based acrylate monomer is bio-based acrylic acid C 8-18 Alkyl ester monomers.

11. The ultraviolet-curable adhesive composition according to claim 10, wherein the bio-based acrylate monomer is one or more selected from the group consisting of 2-octyl acrylate (2-OA), 2-octyl acrylate (NOAA), lauryl acrylate (LA), 2-octadecyl acrylate (STA) and isobornyl acrylate (IBXA). 12 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 52.9 to 75.5 wt % of the acrylate monomer based on the total weight of the ultraviolet curable adhesive composition. 13 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 53.0 to 57.8 wt % of the acrylate monomer based on the total weight of the ultraviolet curable adhesive composition. 14 . The ultraviolet curable adhesive composition according to claim 1 , wherein the acid-containing acrylic monomer is acrylic acid, methacrylic acid, or a combination thereof. 15 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 0.8 to 2.2 wt % of the acid-containing acrylic monomer based on the total weight of the ultraviolet curable adhesive composition. 16 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 0.9 to 2.2 wt % of the acid-containing acrylic monomer based on the total weight of the ultraviolet curable adhesive composition. 17 . The ultraviolet-curable adhesive composition according to claim 1 , wherein the photoinitiator is selected from one or more of an acetophenone-based photoinitiator and a benzoin ether-based photoinitiator. 18 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 0.05 to 0.27 wt % of the photoinitiator based on the total weight of the ultraviolet curable adhesive composition. 19 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 0.17 to 0.27 wt % of the photoinitiator based on the total weight of the ultraviolet curable adhesive composition.

20. The ultraviolet curable adhesive composition of claim 1, wherein the crosslinking agent is a multifunctional ethylenically unsaturated monomer. 21 . The ultraviolet curable adhesive composition according to claim 1 , wherein the crosslinking agent is a multifunctional ethylenically unsaturated monomer comprising 3 to 6 ethylenically unsaturated groups. 22 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 0.05 to 0.11 wt % of the crosslinking agent based on the total weight of the ultraviolet curable adhesive composition. 23 . The ultraviolet curable adhesive composition according to claim 1 , wherein the ultraviolet curable adhesive composition comprises 0.06 to 0.11 wt % of the crosslinking agent based on the total weight of the ultraviolet curable adhesive composition. 24 . The ultraviolet curable adhesive composition according to claim 1 , further comprising an unsaturated nitrogen-containing monomer.

25. The ultraviolet curable adhesive composition according to claim 24, wherein the unsaturated nitrogen-containing monomer is selected from one or more of an acrylamide-based unsaturated monomer, a caprolactam-based unsaturated monomer, a vinyl nitrogen-containing heterocyclic monomer, and acrylonitrile.

26. The ultraviolet curable adhesive composition according to claim 25, wherein: The acrylamide-based unsaturated monomer is one or more selected from the group consisting of N, N-dimethylacrylamide, acrylamide, tert-butylacrylamide, dimethylaminoethylacrylamide, N-octylacrylamide and 4-acryloylmorpholine; and / or The caprolactam-based unsaturated monomer is N-vinylcaprolactam; and / or The vinyl nitrogen-containing heterocyclic monomer is one or more selected from the group consisting of N-vinyl pyrrolidone, vinyl methyl oxazolidinone, vinyl imidazole and vinyl pyridine.

27. The ultraviolet curable adhesive composition of claim 24, wherein the unsaturated nitrogen-containing monomer is N,N-dimethylacrylamide, N-vinylcaprolactam, or a combination. 28 . The ultraviolet curable adhesive composition according to claim 25 , wherein the ultraviolet curable adhesive composition comprises 3 to 20 wt % of the unsaturated nitrogen-containing monomer based on the total weight of the ultraviolet curable adhesive composition.

29. The ultraviolet curable adhesive composition according to claim 25, wherein when the unsaturated nitrogen-containing monomer comprises the acrylamide-based unsaturated monomer, the ultraviolet curable adhesive composition comprises no more than 6.4 wt% of the acrylamide-based unsaturated monomer based on the total weight of the ultraviolet curable adhesive composition.

30. The ultraviolet curable adhesive composition according to claim 25, wherein when the unsaturated nitrogen-containing monomer comprises the caprolactam-based unsaturated monomer, the ultraviolet curable adhesive composition comprises no more than 18.8 wt% of the caprolactam-based unsaturated monomer based on the total weight of the composition. 31 . The ultraviolet curable adhesive composition according to claim 25 , wherein the ultraviolet curable adhesive composition comprises 14.7 to 21.5 wt % of the unsaturated nitrogen-containing monomer based on the total weight of the ultraviolet curable adhesive composition.

32. The ultraviolet curable adhesive composition according to claim 31, wherein: The ultraviolet curable adhesive composition comprises 2.7-5.9 wt % of the acrylamide-based unsaturated monomer based on the total weight of the ultraviolet curable adhesive composition; and / or The ultraviolet curable adhesive composition includes 8.8 to 18.8 wt % of the caprolactam-based unsaturated monomer based on the total weight of the composition.

33. The ultraviolet curable adhesive composition of claim 1, wherein the ultraviolet curable adhesive composition has a bio-based carbon content greater than or equal to 60%.

34. A method for preparing the ultraviolet curable adhesive composition according to any one of claims 1 to 33, the method comprising uniformly mixing the components.

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