UV-curable acrylate composite adhesive and preparation method thereof

Abstract

The invention discloses a UV-curable acrylate composite adhesive and a preparation method thereof, and belongs to the technical field of adhesives. The composite adhesive is composed of 10%-40% of UV polymerizable acrylic resin, 30%-55% of acrylate monomer, 15%-25% of filler, 2%-4% of photoinitiator and 1%-5% of auxiliaries, the resin contains specific urethane acrylate and the like, solid acrylate MB-4-G is preferably selected as the filler, only two-step mixing and dissolving are needed for preparation, and the process is simple and safe. The core advantages are as follows: the curing energy under 395nm LED illumination is less than 300mj / cm, and the speed is far higher than that of a conventional product; the bonding strength is high, and the PVC coating of the KT board can be damaged; the solid content is 100%, no solvent exists, and safety risks and waste are avoided; the filler improves the viscosity and the leveling property, the system stability is good, and no layering is caused when the filler is stored at normal temperature and extreme temperature; and the adhesive is transparent and low in cost, and meets the PET and KT plate compounding requirements in the fields of advertisement consumables and the like.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a UV-curable acrylic composite adhesive and its preparation method. Background Technology

[0002] UV acrylate adhesives are generally based on polyurethane acrylates, epoxy acrylates, and polyester acrylates, combined with some monofunctional or polyfunctional acrylic and acrylate monomers. They are obtained by using one or more photoinitiators to generate free radicals under UV light, which then initiates a copolymerization reaction between the UV resin and the acrylate monomers. Due to their fast curing speed, environmental friendliness (solvent-free), and high bonding strength, UV acrylate adhesives are widely used in advertising consumables, electronic component packaging, building material composites, and medical device assembly.

[0003] With rapid economic development, acrylic adhesives have seen large-scale growth in the advertising consumables industry, primarily in the form of water-based and solvent-based acrylic pressure-sensitive adhesives, with oil-soluble acrylic pressure-sensitive adhesives being the most widely used. However, traditional oil-soluble acrylic pressure-sensitive adhesives require large amounts of solvents, posing risks to manufacturers regarding storage and safety during production. For customers, this necessitates solvent recovery and incineration during the coating process, inevitably leading to some solvent waste.

[0004] UV acrylate products are 100% solids with no added solvents, perfectly avoiding the problems associated with oil-soluble acrylate pressure-sensitive adhesives. They are also generally easy to use and have already seen many applications in the market. However, current UV acrylate products still have some issues that urgently need improvement to meet market demands, such as: low-energy curing, high bond strength, high curing speed, curing effects on KT board substrates of different colors, and low cost. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] Therefore, the purpose of this invention is to provide a UV-curable acrylate composite adhesive and its preparation method. The obtained adhesive has excellent mechanical properties after curing, the preparation method is simple and safe, the UV curing requires low energy, the curing speed is fast, and the cost is low.

[0007] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0008] A UV-curable acrylate composite adhesive is composed of the following raw materials by weight percentage: 10%-40% UV-polymerizable acrylic resin, 30%-55% acrylate monomer, 15%-25% filler, 2%-4% photoinitiator, and 1%-5% additives.

[0009] Among them, the UV-polymerizable acrylic resin is one or more of polyurethane acrylates, epoxy acrylates and polyester acrylates of different molecular weights.

[0010] As a preferred embodiment of the UV-curable acrylate composite adhesive of the present invention, the acrylate monomer is one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, isobornyl acrylate, isobornyl methacrylate, vinyl acetate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, tricyclodecanediethanol diacrylate, tetrahydrofuran acrylate, and 2-phenoxyethyl acrylate.

[0011] As a preferred embodiment of the UV-curable acrylate composite adhesive of the present invention, the polyurethane acrylate includes one or more of FJ5513-5, CR92060, 6910M, A2216-8, 2315B, and 7132.

[0012] As a preferred embodiment of the UV-curable acrylate composite adhesive described in this invention, the filler is one or more of TPU dissolved in acrylic monomer, epoxy resin, and solid acrylate.

[0013] As a preferred embodiment of the UV-curable acrylate composite adhesive described in this invention, the solid acrylate is MB-4-G and the epoxy resin is type 0194 epoxy resin.

[0014] As a preferred embodiment of the UV-curable acrylic composite adhesive of the present invention, the photoinitiator is one or more of 1173, TPO, 184, BP and 819.

[0015] In a preferred embodiment of the UV-curable acrylic composite adhesive described in this invention, the additive is one or more of fumed silica, thiol, and adhesion promoter.

[0016] A method for preparing a UV-curable acrylic composite adhesive, comprising the following steps:

[0017] S1. Weigh the required filler and monomer according to the proportion, mix them evenly, and then disperse them with a disperser until the filler is completely dissolved.

[0018] S2. Weigh out the remaining UV-polymerizable acrylic resin, monomer, photoinitiator, some additives and completely dissolved filler according to the proportion, place them in a container and stir continuously until all materials are completely dissolved.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. Compared to ordinary polyurethane acrylates and epoxy acrylates, which require curing energy of 700-800 mj / cm² or higher, certain polyurethane acrylates, due to their unique molecular structure, can efficiently initiate free radical polymerization under 395nm LED light, reducing the energy required for complete curing of the adhesive layer to <300 mj / cm², thus significantly increasing the curing speed. At the same time, this type of polyurethane acrylate forms a synergistic effect with adhesion promoters, strengthening the interfacial bonding between the adhesive layer and PVC-coated KT boards and 50um PET films. When the PET and KT boards are peeled apart after curing, the PVC coating on the KT board surface can be completely destroyed, far exceeding the bonding strength of ordinary UV composite adhesives. Moreover, polyfunctional acrylate monomers cannot replace this core effect.

[0021] 2. Solid acrylate fillers with excellent compatibility, thanks to their similar compatibility with UV acrylate systems, solve the problems of low viscosity and poor leveling properties in specific polyurethane acrylate pure systems, increasing the viscosity to a range suitable for 50µm thick coating processes. They also avoid the colloidal delamination failure issues caused by materials such as TPU, ordinary epoxy resin, and silicone. The 100% solids content solvent-free design avoids the production safety risks and solvent waste associated with traditional oil-soluble pressure-sensitive adhesives. Furthermore, these solid acrylate fillers can replace some high-priced acrylate monomers, reducing raw material costs. The photoinitiator compounding system ensures the colloid is a colorless / pale yellow transparent liquid, not affecting the appearance requirements of advertising consumables. Overall, the application is convenient and highly adaptable. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below.

[0023] Example 1:

[0024] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate CR92060 (Guangdong Haohui New Materials), 50 parts hydroxyethyl acrylate, 25 parts isoborneol acrylate, 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0025] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0026] Example 2:

[0027] Accurately weigh the following materials and mix them evenly: 25 parts epoxy acrylate 3215 (Guangdong Haohui New Materials), 50 parts hydroxyethyl acrylate, 25 parts isoborneol acrylate, 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0028] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0029] Example 3:

[0030] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate 6910M (Nantong Feierbang New Materials), 50 parts hydroxyethyl acrylate, 25 parts isoborneol acrylate, 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0031] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0032] Example 4:

[0033] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate A2216-8 (Guangdong Zicai Chemical), 50 parts hydroxyethyl acrylate, 25 parts isoborneol acrylate, 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0034] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0035] Example 5:

[0036] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate 2315B (Baojun Chemical), 50 parts hydroxyethyl acrylate, 25 parts isoborneol acrylate, 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0037] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0038] Example 6:

[0039] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate 7132 (Nantong Feierbang New Materials), 50 parts hydroxyethyl acrylate, 25 parts isoborneol acrylate, 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0040] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0041] Example 7:

[0042] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate FJ5513-5 (Guangdong Fengjin New Materials), 50 parts hydroxyethyl acrylate, 25 parts isoborneol acrylate, 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0043] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0044] Example 8:

[0045] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate FJ5513-5 (Guangdong Fengjin New Materials), 40 parts hydroxyethyl acrylate, 20 parts isoborneol acrylate, 15 parts TPU, 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0046] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0047] Example 9:

[0048] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate FJ5513-5 (Guangdong Fengjin New Materials), 40 parts hydroxyethyl acrylate, 20 parts isoborneol acrylate, 15 parts epoxy resin 0194 (Nantong Feierbang New Materials), 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0049] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0050] Example 10:

[0051] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate FJ5513-5 (Guangdong Fengjin New Materials), 40 parts hydroxyethyl acrylate, 20 parts isoborneol acrylate, 15 parts solid acrylate MB-4-G (Bolier Chemical), 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0052] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0053] Example 11:

[0054] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate FJ5513-5 (Guangdong Fengjin New Materials), 50 parts hydroxyethyl acrylate, 10 parts isoborneol acrylate, 15 parts solid acrylate MB-4-G (Bolier Chemical), 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0055] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0056] Example 12:

[0057] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate FJ5513-5 (Guangdong Fengjin New Materials), 50 parts hydroxyethyl acrylate, 25 parts solid acrylate MB-4-G (Bolier Chemical), 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0058] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0059] Comparative Example 1

[0060] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate CR92060 (Guangdong Haohui New Materials), 50 parts hydroxyethyl acrylate, 23 parts isoborneol acrylate, 2 parts trimethylolpropane triacrylate, 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0061] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0062] Comparative Example 2

[0063] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate CR92060 (Guangdong Haohui New Materials), 50 parts hydroxyethyl acrylate, 23 parts isoborneol acrylate, 2 parts fumed silica 4740 (Yoshida New Technology), 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0064] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0065] Comparative Example 3

[0066] Accurately weigh the following materials and mix them evenly: 25 parts polyurethane acrylate CR92060 (Guangdong Haohui New Materials), 50 parts hydroxyethyl acrylate, 20 parts isoborneol acrylate, 5 parts fumed silica 4740 (Yoshida New Technology), 2 parts adhesion promoter M221 (Guangdong Haohui New Materials), 1 part 184 and 1 part TPO.

[0067] The prepared composite adhesive is coated on a KT board with a thickness of 50 μm, and then a 50 μm PET is coated on its surface. The laminated sample is then irradiated with a UV lamp to obtain the final cured sample.

[0068] The samples prepared in the above 12 examples and 3 comparative examples were subjected to tear tests on PET and KT boards in the same manner, and the viscosity and thermal stability of the colloids were also tested. The test results are shown in Tables 1 and 2:

[0069] Table 1 Performance test data for Examples 1-12 Example <![CDATA[When the energy < 300 mj / cm 2 is the surface of the KT board completely damaged?]]> Colloidal viscosity (cps) Status after 1 month of storage at room temperature 50℃ storage status after 1 month Stored at -20℃ for 1 month. Energy required for complete curing of adhesive surface 1 no 534 transparent transparent transparent <![CDATA[>800mJ / cm 2 ]]> 2 no 483 transparent transparent transparent <![CDATA[>700mJ / cm 2 ]]> 3 no 513 transparent transparent transparent <![CDATA[>800mJ / cm 2 ]]> 4 no 621 transparent transparent transparent <![CDATA[>800mJ / cm 2 ]]> 5 no 683 transparent transparent transparent <![CDATA[>500mj / cm 2 ]]> 6 no 527 transparent transparent transparent <![CDATA[>700mJ / cm 2 ]]> 7 yes 791 transparent transparent transparent <![CDATA[>250mj / cm 2 ]]> 8 yes 4922 Layering Layering Layering <![CDATA[>250mj / cm 2 ]]> 9 yes 5671 Layering Layering Layering <![CDATA[>250mj / cm 2 ]]> 10 yes 6853 transparent transparent transparent <![CDATA[>250mj / cm 2 ]]> 11 yes 5542 transparent transparent transparent <![CDATA[>250mj / cm 2 ]]> 12 yes 7981 transparent transparent transparent <![CDATA[>250mj / cm 2 ]]>

[0070] Table 2 Performance test data for comparative examples 1-3 Example <![CDATA[When the energy < 300 mj / cm 2 is the surface of the KT board completely damaged?]]> Colloidal viscosity (cps) Status after 1 month of storage at room temperature 50℃ storage status after 1 month Stored at -20℃ for 1 month. Energy required for complete curing of adhesive surface 1 no 542 transparent transparent transparent <![CDATA[>800mJ / cm 2 ]]> 2 no 2117 Layering Layering Layering <![CDATA[>700mJ / cm 2 ]]> 3 no 23752 Layering Layering Layering <![CDATA[>800mJ / cm 2 ]]>

[0071] Examples 1-7 show that when FJ5513-5 is used as the main resin, it can ensure a performance of 300 mj / cm². 2It fully cures under the given energy conditions, and when torn after curing, it can completely destroy the surface of the KT board. However, its viscosity is relatively low, and its leveling properties are poor. Therefore, it is necessary to increase the viscosity to improve its leveling properties. As can be seen from Examples 8-10, monomer-soluble TPU, epoxy resin 0194, and MB-4-G can all improve the viscosity of the colloid. However, with changes in storage conditions and the extension of time, the colloid solutions of the former two are more prone to separation, leading to the failure of the colloid itself. In contrast, Example 10 has better leveling properties and stability. In order to further reduce costs, the monomer and filler ratios were further adjusted to improve the product's cost-effectiveness while ensuring that the performance meets the standards. As can be seen from Comparative Example 1, in order to increase the curing speed and reduce the minimum complete curing energy, multifunctional monomers were tried, but they had almost no effect. It is possible that the curing energy of the system is mainly determined by the main UV resin. As can be seen from Comparative Examples 2-3, fumed silica has a good effect on thickening and improving leveling properties, but it will cause a serious decrease in the overall stability of the system. The filler MB-4-G solid acrylate can not only improve the viscosity, but also has a similarity to the system structure, resulting in a "like dissolves like" effect, which makes the final system more stable.

[0072] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A UV-curable acrylic composite adhesive, characterized in that, It is composed of the following raw materials by weight percentage: 10%-40% UV-polymerizable acrylic resin, 30%-55% acrylate monomer, 15%-25% filler, 2%-4% photoinitiator, and 1%-5% additives. Among them, the UV-polymerizable acrylic resin is one or more of polyurethane acrylates, epoxy acrylates and polyester acrylates of different molecular weights.

2. The UV-curable acrylic composite adhesive according to claim 1, characterized in that, The acrylate monomer is one or more of the following: hydroxyethyl acrylate, hydroxyethyl methacrylate, isobornyl acrylate, isobornyl methacrylate, vinyl acetate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, tricyclodecanediethanol diacrylate, tetrahydrofuran acrylate, and 2-phenoxyethyl acrylate.

3. The UV-curable acrylic composite adhesive according to claim 1, characterized in that, The polyurethane acrylate includes one or more of FJ5513-5, CR92060, 6910M, A2216-8, 2315B, and 7132.

4. The UV-curable acrylic composite adhesive according to claim 1, characterized in that, The filler is one or more of TPU dissolved in acrylic monomer, epoxy resin, and solid acrylate.

5. The UV-curable acrylic composite adhesive according to claim 4, characterized in that, The solid acrylate is MB-4-G, and the epoxy resin is type 0194 epoxy resin.

6. The UV-curable acrylic composite adhesive according to claim 1, characterized in that, The photoinitiator is one or more of 1173, TPO, 184, BP and 819.

7. The UV-curable acrylic composite adhesive according to claim 1, characterized in that, The additive is one or more of the following: fumed silica, thiol, and adhesion promoter.

8. A method for preparing a UV-curable acrylic composite adhesive as described in any one of claims 1-7, characterized in that, The steps are as follows: S1. Weigh the required filler and monomer according to the proportion, mix them evenly, and then disperse them with a disperser until the filler is completely dissolved. S2. Weigh out the remaining UV-polymerizable acrylic resin, monomer, photoinitiator, some additives and completely dissolved filler according to the proportion, place them in a container and stir continuously until all materials are completely dissolved.