Composition capable of being rapidly cured by UV and UV adhesive film

Abstract

The invention relates to the technical field of adhesives, in particular to a composition capable of being rapidly subjected to UV curing and a UV adhesive film. The composition capable of being quickly UV-cured is prepared from the following components in parts by weight: 100 parts of acrylate copolymer, 30 to 60 parts of alicyclic epoxy resin, 1 to 10 parts of epoxy-terminated hyperbranched polyether and 0.1 to 4 parts of cationic photoinitiator. The adhesive film prepared from the composition has proper bonding strength before UV curing, can realize rapid UV curing, and has relatively high stripping force and shearing strength after curing.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, and in particular to a composition and UV-curable adhesive film that can be rapidly UV cured. Background Technology

[0002] Even without UV curing, UV-curable adhesive films provide suitable initial peel force for bonding and fixation, and the initial adhesive force is relatively low, allowing for re-bonding without residue after the film is peeled off. After further UV curing following bonding and positioning, the adhesive film's bonding strength is enhanced, and its peel force and shear strength after curing are further improved.

[0003] Traditional UV-curable adhesive films are divided into UV free radical curing and UV cationic curing. However, UV free radical curing is fast but results in low film strength, which cannot meet the requirements of structural bonding and is mostly used in UV-induced tack reduction. On the other hand, UV cationic curing is slower, and the curing process is generally accelerated by increasing the content of cationic photoinitiator or the light intensity, but this can easily lead to a decrease in the adhesive performance of the film. Therefore, developing an adhesive film that combines rapid UV curing and high bonding strength is of great significance.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a composition and a UV film that can be rapidly UV cured. The film composed of the composition of this invention has suitable adhesive strength before UV curing, can achieve rapid UV curing, and has high peel strength and shear strength after curing.

[0006] To achieve the above-mentioned objectives of the present invention, a first aspect of the present invention provides a composition capable of rapid UV curing, comprising the following components in parts by weight: 100 parts of acrylate copolymer 30-60 parts of alicyclic epoxy resin 1-10 parts of terminal epoxy hyperbranched polyether 0.1 to 4 parts of cationic photoinitiator.

[0007] Further, the composition comprises the following components in parts by weight: 100 parts of acrylate copolymer 40-50 parts of alicyclic epoxy resin 3-7 parts of terminal epoxy hyperbranched polyether 0.5 to 2 parts of cationic photoinitiator.

[0008] Furthermore, the alicyclic epoxy resin has a functionality of not less than 2.

[0009] Further, the acrylate copolymer comprises the following monomer components in parts by weight: 40-60 parts of hard monomer, 20-40 parts of soft monomer and 1-15 parts of functional monomer, wherein the functional monomer comprises (meth)acrylate monomers containing epoxy groups.

[0010] Furthermore, the acrylate copolymer comprises the following monomer components in parts by weight: 45-55 parts of hard monomer, 25-35 parts of soft monomer, and 5-10 parts of functional monomer.

[0011] A second aspect of the present invention provides a UV adhesive film comprising the rapidly UV-curable composition provided in the first aspect of the present invention.

[0012] Furthermore, the thickness of the adhesive film is 10–100 μm.

[0013] Furthermore, the peel force of the adhesive film before UV curing is not higher than 0.25 N / mm, and / or the peel force of the adhesive film after UV curing for 1 min is not lower than 0.7 N / mm.

[0014] Furthermore, the shear strength of the adhesive film before UV curing is not higher than 0.3 MPa, and / or the shear strength of the adhesive film after UV curing for 10 min is not lower than 1 MPa.

[0015] Furthermore, the peel strength of the adhesive film after UV curing for 72 h (final curing) is not less than 1 N / mm and the shear strength is not less than 7 MPa.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The composition of the present invention that can be rapidly UV cured, by introducing a certain amount of alicyclic epoxy resin, under the initiation of a cationic photoinitiator, the epoxy groups of the alicyclic epoxy resin undergo ring-opening and cross-linking polymerization with the acrylate copolymer to rapidly form a cross-linking network structure, thereby improving the peel force and shear strength of the cured film. Furthermore, the alicyclic structure of the alicyclic epoxy resin has a certain rigidity, which can improve the shear strength of the film and reduce the curing shrinkage rate of the film. A small amount of terminal epoxy hyperbranched polyether is added to the composition. Due to its hyperbranched structure, and the fact that the terminal epoxy groups can be ring-opened and cross-linked with the epoxy groups of the alicyclic epoxy resin, the terminal epoxy hyperbranched polyether can be interspersed in the cross-linking network structure of the film, so that the cured film has a certain flexibility and avoids the cured film from being too hard.

[0017] (2) The adhesive film prepared by using the composition of the present invention that can be rapidly UV cured has suitable adhesion before UV curing, and the peel force after UV curing for 1 min can reach more than 0.7 N / mm, the shear strength after UV curing for 10 min can reach more than 1 MPa, and the peel force after final curing (UV curing for 72 h) is not less than 1 N / mm and the shear strength is not less than 7 MPa. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0019] It should be noted that "(meth)acrylate" in this invention refers to one or a combination of two of acrylates and methacrylates.

[0020] The first aspect of the present invention provides a composition capable of rapid UV curing, comprising the following components in parts by weight: 100 parts of acrylate copolymer 30-60 parts of alicyclic epoxy resin 1-10 parts of terminal epoxy hyperbranched polyether 0.1 to 4 parts of cationic photoinitiator.

[0021] The rapid UV-curable composition of this invention, by adding a certain amount of alicyclic epoxy resin, allows a cationic photoinitiator to initiate the ring-opening of the epoxy groups of the alicyclic epoxy resin under ultraviolet irradiation, resulting in rapid crosslinking polymerization with the acrylate copolymer to form a crosslinked network structure. This enhances the peel strength and shear strength of the UV-cured film. The epoxy groups of the alicyclic epoxy resin are located on the alicyclic structure. The geometric tension of the alicyclic structure places the epoxy groups in a high-energy state, lowering the activation energy of the ring-opening reaction and making it easier for the cationic photoinitiator to initiate ring-opening, thereby increasing the curing speed. Furthermore, the rigid alicyclic structure results in less molecular rearrangement during curing, forming a rigid and compact crosslinked network after crosslinking, with a higher crosslinking density, which reduces curing shrinkage.

[0022] This invention introduces terminal epoxy hyperbranched polyethers. Because terminal epoxy hyperbranched polyethers have a hyperbranched structure, the terminal epoxy groups have low steric hindrance and can also crosslink with alicyclic epoxy resins, which helps to increase the crosslinking density and form a three-dimensional network structure containing branched structures. This can disperse the shrinkage stress during the curing process and achieve a good balance between film hardness and flexibility.

[0023] In a specific embodiment of the present invention, the functionality of the alicyclic epoxy resin is not less than 2. The functionality of the alicyclic epoxy resin of the present invention is limited to the above range, which helps to improve the curing speed.

[0024] In a specific embodiment of the present invention, the alicyclic epoxy resin includes at least one of poly[(2-epoxyethylene)-1,2-cyclohexanediol]2-ethyl-2-(hydroxymethyl)-1,3-propanediol ether, (3,4,3',4'-diepoxy)bicyclohexane, and 1,3-bis[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]-1,1,3,3-tetramethyldisiloxane.

[0025] In a specific embodiment of the present invention, the alicyclic epoxy resin in the composition is 30 to 60 parts by weight relative to 100 parts of the acrylate copolymer, specifically 30, 35, 40, 45, 50, 55, or 60 parts, or any value between any two extremes, preferably 40 to 50 parts. Limiting the amount of alicyclic epoxy resin within the above range allows it to both improve the UV curing speed of the film and impart excellent adhesive strength. When the amount of alicyclic epoxy resin is too high, although the UV curing speed is increased, it is detrimental to the flexibility and conformability of the film; when its amount is too low, the improvement in UV curing speed and adhesive strength is not significant.

[0026] In a specific embodiment of the present invention, the terminal epoxy hyperbranched polyether can be prepared according to existing technology, such as HBOPE1 prepared by referring to the method in Yang Su. Preparation of terminal epoxy hyperbranched polyether and its application in high solids coatings ([D]. Jiangnan University, 2021.DOI:10.27169 / d.cnki.gwqgu.2021.000207.).

[0027] In a specific embodiment of the present invention, the amount of the terminal epoxy hyperbranched polyether in the composition relative to 100 parts of the acrylate copolymer is 1 to 10 parts, specifically 1 part, 2 parts, 3 parts, 5 parts, 6 parts, 7 parts, 8 parts, 10 parts, or any value between any two extremes, preferably 3 to 7 parts. Adjusting the amount of terminal epoxy hyperbranched polyether within the above range can balance the strength and flexibility of the adhesive film. When the amount of terminal epoxy hyperbranched polyether is too high, the shear strength of the cured adhesive film is insufficient; when its amount is too low, the toughening effect is not obvious.

[0028] In a specific embodiment of the present invention, the cationic photoinitiator includes at least one of diphenyl[4-(phenylthio)phenyl]-hexafluoroantimonate sulfonium (cationic photoinitiator 1176), isopropylphenylcyclopentadiene iron hexafluorophosphate (cationic photoinitiator 261), and isopropylphenyl ferrocene hexafluoroantimonate (cationic photoinitiator 262).

[0029] In a specific embodiment of the present invention, the amount of the cationic photoinitiator in the composition relative to 100 parts of the acrylate copolymer is 0.1 to 4 parts, specifically 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 4 parts, or any value between any two of these values, preferably 0.5 to 2 parts.

[0030] In a specific embodiment of the present invention, the acrylate copolymer is mainly obtained by copolymerization of (meth)acrylate monomers; it includes the following monomer components in parts by weight: 40-60 parts of hard monomer, 20-40 parts of soft monomer and 1-15 parts of functional monomer.

[0031] In a specific embodiment of the present invention, the hard monomer includes at least one of methyl methacrylate, ethyl methacrylate, and isobornyl acrylate.

[0032] In a specific embodiment of the present invention, the content of the hard monomer in the acrylate copolymer is 40 to 60 parts, specifically 40 parts, 45 parts, 50 parts, 55 parts, 60 parts or any value between any two of these values, preferably 45 to 55 parts.

[0033] In a specific embodiment of the present invention, the soft monomer includes at least one of butyl acrylate, isooctyl acrylate, and lauryl methacrylate.

[0034] In a specific embodiment of the present invention, the content of the soft monomer in the acrylate copolymer is 20 to 40 parts, specifically 20 parts, 25 parts, 30 parts, 35 parts, 40 parts or any value between any two of these values, preferably 25 to 35 parts.

[0035] In a specific embodiment of the present invention, the functional monomer comprises (meth)acrylate monomers containing epoxy groups. Further, the functional monomer comprises at least one selected from glycidyl methacrylate, 3,4-epoxycyclohexylmethyl methacrylate, and 3,4-epoxycyclohexyl methacrylate. In the present invention, a functional monomer containing epoxy groups is introduced into the acrylate copolymer, and during UV curing of the film, the epoxy groups in the acrylate copolymer undergo ring-opening polymerization with the epoxy groups of the alicyclic epoxy resin.

[0036] In a specific embodiment of the present invention, the content of the functional monomer in the acrylate copolymer is 1 to 15 parts, specifically 1 part, 3 parts, 5 parts, 8 parts, 10 parts, 12 parts, 15 parts or any value between any two of these values, preferably 5 to 10 parts.

[0037] In a specific embodiment of the present invention, the acrylate copolymer further includes a thermal initiator for initiating monomer polymerization. The content of the thermal initiator in the acrylate copolymer is 0.1 to 0.9 parts, specifically 0.1 parts, 0.3 parts, 0.5 parts, 0.6 parts, 0.9 parts, or any value between any two extremes thereof.

[0038] In a specific embodiment of the present invention, the thermal initiator may be a conventional azo initiator, including but not limited to at least one of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleratenitrile, and dimethyl azobisisobutyrate.

[0039] In the preparation of the acrylate copolymer, a certain amount of solvent may be added to adjust the solid content and promote the reaction. The solvent may be a conventional organic solvent, including but not limited to at least one of ethyl acetate, toluene, butanone, acetone, and isopropanol. The solid content of the acrylate copolymer may be adjusted to 30-40%.

[0040] In a specific embodiment of the present invention, the acrylate copolymer can be prepared by conventional polymerization methods. The following is a preparation method, which includes: weighing raw materials in proportion and reacting them at 50-80°C for 12-24 h under a protective atmosphere.

[0041] In the preparation of the acrylate copolymer, the protective atmosphere can be nitrogen, but is not limited to it; the reaction temperature can be 50℃, 60℃, 70℃, 80℃ or any value between any two of these two values; and the reaction time can be 12h, 16h, 20h, 24h or any value between any two of these two values.

[0042] In this invention, there are no limitations on the method for preparing the adhesive from the composition; commonly used adhesive preparation methods can be used. This invention provides a method for preparing an adhesive composed of a composition, comprising the following steps: mixing the components in proportion, stirring evenly, and allowing it to stand to defoam, thereby obtaining the adhesive to be coated.

[0043] In a specific embodiment of the present invention, a certain amount of solvent may be added during the preparation of the adhesive to facilitate coating. The solvents may be any of those listed above. The solid content of the adhesive may be set to 30-40%.

[0044] It is understood that, for the convenience of production, transportation and sales, the UV-curable composition of the present invention only limits the composition of the components and not the form in which the components exist; that is, the components can be mixed together or stored separately. The mixed or separate storage method can be selected according to the actual use.

[0045] A second aspect of the present invention provides a UV adhesive film comprising the rapidly UV-curable composition provided in the first aspect of the present invention.

[0046] This invention also provides an optional preparation method for the above-mentioned adhesive film, comprising the following steps: applying the adhesive to be coated onto the surface of a release film, and then drying it to form a UV adhesive film. When a double-sided adhesive film is required, it is coated onto the surface of the release film; when a single-sided adhesive film is required, it is coated onto one side of the substrate. The method can be selected according to actual needs.

[0047] In a specific embodiment of the present invention, the drying temperature is 80-100°C and the drying time is 3-5 min.

[0048] In practice, the coating method of this invention is not limited, and can be roller coating, blade coating, or dip coating, etc. In practice, a coater can be used for coating.

[0049] In a specific embodiment of the present invention, the substrate may include at least one of polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polyimide (PI). The thickness of the substrate can be freely selected according to actual needs and is not particularly limited. For example, it can be 25–75 μm, specifically 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 75 μm, or any value between any two extremes thereto.

[0050] In a specific embodiment of the present invention, the release film can be a PET silicone release film. The thickness of the release film can be freely selected according to actual needs and is not particularly limited. For example, it can be set to 38-50 μm, specifically 38 μm, 40 μm, 45 μm, 50 μm or any value between the two extremes.

[0051] In a specific embodiment of the present invention, in order to facilitate winding and transportation and to avoid dirt on the surface of the film, a release film can be applied to the surface of the UV film.

[0052] In a specific embodiment of the present invention, the thickness of the adhesive film is 10–100 μm. In different embodiments, the thickness of the adhesive film can be 10 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 100 μm, or any value between any two extremes, preferably 30–80 μm.

[0053] In a specific embodiment of the present invention, after the adhesive film is adhered to the surface of the object to be adhered, it is subjected to UV light irradiation; wherein the UV light irradiation includes: irradiation with UVC band UV light, with a radiation energy of 200-400 mJ / cm². 2 .

[0054] In a specific embodiment of the present invention, the peel force of the adhesive film before UV curing is not higher than 0.25 N / mm, and the shear strength is not higher than 0.3 MPa.

[0055] In a specific embodiment of the present invention, the peel strength of the adhesive film after UV curing for 1 min is not less than 0.7 N / mm, and the shear strength after UV curing for 10 min is not less than 1 MPa; after UV curing for 72 h (final curing), the peel strength is not less than 1 N / mm and the shear strength is not less than 7 MPa. It should be noted that the present invention uses UV curing for 72 h as the final curing time. In actual use, the final curing time may vary due to the thickness of the adhesive film and the influence of the surrounding environment, and the specific time is not limited.

[0056] The following specific embodiments further illustrate the purpose and advantages of the present invention, but these embodiments should not be regarded as limitations of the present invention. In the following embodiments, 1g represents 1 part by weight.

[0057] The HBOPE1 described in the following examples was prepared according to the method described in Yang Su. Preparation of End-Epoxy Hyperbranched Polyethers and Their Application in High Solids Coatings ([D]. Jiangnan University, 2021. DOI:10.27169 / d.cnki.gwqgu.2021.000207.).

[0058] Example 1 50 g of methyl methacrylate, 30 g of lauryl methacrylate, 7.5 g of 3,4-epoxycyclohexyl methacrylate and 0.4 g of azobisisobutyronitrile were placed in a reactor and polymerized at 65 °C for 8 h under a nitrogen atmosphere. A certain amount of ethyl acetate was added to obtain an acrylate copolymer with a solid content of 35%.

[0059] 100 g of the acrylate copolymer prepared above, 45 g of alicyclic epoxy resin poly[(2-epoxyethylene)-1,2-cyclohexanediol]2-ethyl-2-(hydroxymethyl)-1,3-propanediol ether, 5 g of terminal epoxy hyperbranched polyether, 1 g of cationic photoinitiator 1173, and a certain amount of ethyl acetate were mixed evenly and allowed to stand to defoam, resulting in an adhesive with a solid content of 35% to be coated.

[0060] The adhesive was applied to the surface of a 50 μm thick PET monosilicone release film and placed in a 90℃ oven for 4 min to form a 50 μm thick adhesive film.

[0061] Example 2 This embodiment is based on Example 1, with the only difference being the amount of some components in the composition. The preparation method and solid content are the same as in Example 1, and the specific differences are as follows: 30 g of alicyclic epoxy resin, 1 g of terminal epoxy hyperbranched polyether and 0.1 g of cationic photoinitiator.

[0062] Example 3 This embodiment is based on Example 1, with the only difference being the amount of some components in the composition. The preparation method and solid content are the same as in Example 1, and the specific differences are as follows: 40 g of alicyclic epoxy resin, 3 g of terminal epoxy hyperbranched polyether and 0.5 g of cationic photoinitiator.

[0063] Example 4 This embodiment is based on Example 1, with the only difference being the amount of some components in the composition. The preparation method and solid content are the same as in Example 1, and the specific differences are as follows: 50 g of alicyclic epoxy resin, 7 g of terminal epoxy hyperbranched polyether, and 2 g of cationic photoinitiator.

[0064] Example 5 This embodiment is based on Example 1, with the only difference being the amount of some components in the composition. The preparation method and solid content are the same as in Example 1, and the specific differences are as follows: 60 g of alicyclic epoxy resin, 10 g of terminal epoxy hyperbranched polyether, and 4 g of cationic photoinitiator.

[0065] Example 6 group This example group is based on Example 1, with the only difference being the amount of monomer used in the acrylate copolymer. The preparation method and solid content are the same as in Example 1, and the specific differences are as follows: Example 6a: 40 g methyl methacrylate, 40 g lauryl methacrylate, 15 g 3,4-epoxycyclohexyl methacrylate and 0.5 g azobisisobutyronitrile; Example 6b: 45 g methyl methacrylate, 35 g lauryl methacrylate, 10 g 3,4-epoxycyclohexyl methacrylate and 0.45 g azobisisobutyronitrile; Example 6c: 55 g methyl methacrylate, 25 g lauryl methacrylate, 5 g 3,4-epoxycyclohexyl methacrylate and 0.35 g azobisisobutyronitrile; Example 6d: 60 g methyl methacrylate, 20 g lauryl methacrylate, 1 g 3,4-epoxycyclohexyl methacrylate and 0.3 g azobisisobutyronitrile.

[0066] Comparative Example 1 This comparative example group was prepared in accordance with Example 1, except that the amount of alicyclic epoxy resin was different. The preparation method and solid content were the same as in Example 1. The specific differences are as follows: Comparative Example 1a: 65 g of alicyclic epoxy resin; Comparative Example 1b: 25 g of alicyclic epoxy resin; Comparative Example 1c: Does not contain alicyclic epoxy resin.

[0067] Comparative Example 2 This comparative example group was conducted in accordance with Example 1, except that the amount of terminal epoxy hyperbranched polyether was different. All other aspects were the same as in Example 1, and the specific differences are as follows: Comparative Example 2a: 0.5 g of terminal epoxy hyperbranched polyether; Comparative Example 2b: 13 g of terminal epoxy hyperbranched polyether; Comparative Example 2c: Hyperbranched polyether without terminal epoxy groups.

[0068] Comparative Example 3 Groups This comparative example group was conducted in accordance with Example 1, except that the amount or type of functional monomer was different. Everything else was the same as in Example 1, and the specific differences are as follows: Comparative Example 3a: 0.5 g of 3,4-epoxycyclohexyl methacrylate; Comparative Example 3b: 20 g of 3,4-epoxycyclohexyl methacrylate; Comparative Example 3c: 2-hydroxyethyl acrylate was used instead of 3,4-epoxycyclohexyl methacrylate by equal mass.

[0069] Test case The films prepared in the above embodiments and comparative examples were subjected to the following tests. The test results are shown in Table 1, and the test methods are as follows.

[0070] 1. 180° peel force test The test was conducted in accordance with the national standard GB / T 2792-2014 "Test Method for Peel Strength of Adhesive Tapes". A 300 mm × 25 mm sample strip was taken (stored away from light). The adhesive film side was attached to a 50 μm PET film, and then the release film was peeled off. The other side of the adhesive film was attached to a clean mirror steel plate and rolled back and forth twice with a 2 kg roller. After being placed at room temperature (RT, 23℃ / 50%RH) for 20 min, the test was conducted. The peel speed was set to 300 mm / min, and the peel force of the adhesive film before UV exposure was recorded.

[0071] The rolled sample was then irradiated with UVC light at an energy of 300 mJ / cm². 2 Peeling force was tested at room temperature for different durations after UV curing. The peeling speed was set to 300 mm / min. Peeling force of the sample was recorded at 1 min, 10 min, 1 h, 12 h and 72 h after UV curing.

[0072] 2. Shear strength test According to the national standard GB / T 7124-2008 "Determination of tensile shear strength of adhesives (rigid material to rigid material)", a 12.5 mm × 25 mm sample strip was taken, and the adhesive film was attached to the center of a 30 mm × 50 mm ternary aluminum plate. The release film was removed, and then another 30 mm × 50 mm ternary aluminum plate was pressed directly on top of the adhesive film, so that the adhesive film adhered to the middle of the two ternary aluminum plates. A 2 kg pressure roller was used to press for 30 s, and the shear strength of the adhesive film before UV exposure was tested at room temperature.

[0073] A 12.5 mm × 25 mm adhesive film sample was attached to a 30 mm × 50 mm triaxial aluminum plate. After removing the release film, the adhesive film surface was irradiated with UVC light at an energy of 200 mJ / cm². 2 Immediately after irradiation, the adhesive film was attached to another 30 mm × 50 mm tri-series aluminum plate and pressed with a 2 kg pressure roller for 30 s. The shear strength of the sample after UV curing at different times was tested at room temperature. The tensile shear rate was set to 10 mm / min. The shear strength of the sample was recorded at 10 min, 1 h, 12 h and 72 h after UV curing.

[0074] 3. Shrinkage test Volume shrinkage rate was determined by density method: Referring to the national standard GB / T 15223-2008 "Determination of density of liquid plastic resins by specific gravity bottle method", the density of the film was tested before UV curing and after 72 hours of UV curing. The UV radiation energy was 200 mJ / cm². 2The volume shrinkage rate is calculated based on the density before and after UV exposure. Shrinkage rate = (ρafter - ρbefore) / ρbefore × 100%.

[0075] Table 1 Performance test results of different embodiments and comparative examples

[0076] The test results above show that the adhesive film made from the composition of the present invention has a peel force of no more than 0.25 N / mm and a shear strength of no more than 0.3 MPa before UV curing, exhibiting suitable adhesive properties. After UV curing for 1 min, the peel force is no less than 0.7 N / mm, and after curing for 10 min, the shear strength is no less than 1 MPa, indicating fast curing speed. After final curing, the peel force is no less than 1 N / mm, the shear strength is no less than 7 MPa, and the curing shrinkage rate is <3%, indicating low curing shrinkage rate, making it suitable for rapid curing and high adhesive strength requirements.

[0077] The test results of Comparative Example 1 show that when the amount of alicyclic epoxy resin in the composition of the present invention is higher than the specified range, the peel force of the film after UV curing is low. This is because the crosslinking density of the film is too strong, which leads to a decrease in peel force. When the amount is lower than the specified range, the shear strength after final curing is low. If alicyclic epoxy resin is not added, the peel force and shear strength are both low due to the decrease in crosslinking within the film.

[0078] The test results of the two comparative examples show that when the amount of terminal epoxy hyperbranched polyether in the composition of the present invention is lower than the limit or no terminal epoxy hyperbranched polyether is added, there is no toughening effect in the system, resulting in a low peel strength of the film after UV curing; while when the amount of terminal epoxy hyperbranched polyether exceeds the limit, the toughening effect of the terminal epoxy hyperbranched polyether is strong, resulting in a low shear strength of the film after curing.

[0079] The test results of the three comparative examples show that when the amount of functional monomers in the composition of the present invention exceeds the limit, it will affect the peel force and shear strength of the film after UV curing. If hydroxyl-containing functional monomers are used instead of epoxy-containing functional monomers, the hydroxyl monomers cannot effectively polymerize to form a crosslinking network under the Lewis acid catalysis generated by the cationic photoinitiator, resulting in a significant reduction in the crosslinking density of the system, curing failure or serious insufficiency, resulting in low peel force and shear strength after UV curing.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composition capable of rapid UV curing, characterized in that, Includes the following components by weight: 100 parts of acrylate copolymer 30-60 parts of alicyclic epoxy resin 1-10 parts of terminal epoxy hyperbranched polyether 0.1 to 4 parts of cationic photoinitiator.

2. The rapidly UV-curable composition according to claim 1, characterized in that, Includes the following components by weight: 100 parts of acrylate copolymer 40-50 parts of alicyclic epoxy resin 3-7 parts of terminal epoxy hyperbranched polyether 0.5 to 2 parts of cationic photoinitiator.

3. The rapidly UV-curable composition according to claim 1 or 2, characterized in that, The alicyclic epoxy resin has a functionality of not less than 2.

4. The rapidly UV-curable composition according to claim 1 or 2, characterized in that, The acrylate copolymer comprises the following monomer components in parts by weight: 40-60 parts of hard monomer 20-40 parts of soft monomer 1 to 15 parts of functional monomer; The functional monomers include (meth)acrylate monomers containing epoxy groups.

5. The rapidly UV-curable composition according to claim 4, characterized in that, The acrylate copolymer comprises the following monomer components in parts by weight: 45-55 parts of hard monomer 25-35 parts of soft monomer 5 to 10 parts of functional monomers.

6. A UV adhesive film, characterized in that, The composition includes the rapidly UV-curable composition according to any one of claims 1 to 5.

7. The UV film according to claim 6, characterized in that, The thickness of the adhesive film is 10–100 μm.

8. The UV film according to claim 7, characterized in that, The peel force of the adhesive film before UV curing is not higher than 0.25 N / mm, and / or the peel force of the adhesive film after UV curing for 1 min is not lower than 0.7 N / mm.

9. The UV film according to claim 7, characterized in that, The shear strength of the adhesive film before UV curing is not higher than 0.3 MPa, and / or the shear strength of the adhesive film after UV curing for 10 min is not lower than 1 MPa.

10. The UV film according to claim 8 or 9, characterized in that, The peel strength and shear strength of the adhesive film after UV curing for 72 h (final curing) shall not be less than 1 N / mm and 7 MPa respectively.

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