Photocurable acrylic adhesive and adhesive tape

Abstract

According to the photocurable acrylic adhesive and the adhesive tape, acrylate is adopted as a monomer, a special reactive diluent is added, and the special ratio of the monomer to an initiator to the reactive diluent is adjusted, so that optimized prepolymer glue is obtained. By selecting halogen-free flame-retardant filling materials and adjusting the specific matching proportion of the filling materials, the finished adhesive tape can reach the flame-retardant grade of UL94V-0 when being used for laminating a battery aluminum plate. Meanwhile, the ratio of the filler to the acrylic resin is adjusted, so that the adhesive tape has a good compression force value, the change of the volume of the battery can be effectively made up during charging and discharging of the battery, the risks of displacement, falling, collision and the like caused by loosening of the battery are reduced, the safety of the battery is greatly improved, and the risk of spontaneous combustion caused by damage of the battery is reduced. And extrusion and curing are performed in a slit coating manner, and the integrally-formed pressure-sensitive adhesive tapes with different thicknesses can be obtained only by adjusting a crack between the upper coating roller and the lower coating roller, so that the production time is greatly shortened.

Description

Technical Field

[0001] The invention relates to the technical field of acrylic resins, in particular to a light-curable acrylic adhesive and an adhesive tape. Background Art

[0002] With the continuous advancement of science and technology and people's continued attention to environmental protection and energy conservation, the automotive industry is gradually transforming from fuel vehicles to new energy vehicles. Among them, electric vehicles, as one of the important representatives of green travel, have been vigorously promoted. Electric vehicles mainly rely on power batteries to provide driving power for the vehicle. Compared with fuel vehicles, they significantly reduce automobile exhaust emissions and make great contributions to environmental protection. Power batteries usually use battery cells as core components, which are assembled into modules and then integrated into battery packs. In this process, various components need to be bonded and fixed. At the same time, due to the risk of thermal runaway of power batteries, their safety performance has attracted much attention. Therefore, the manufacturing process and requirements of electric vehicle power batteries are increasing, and the performance of the bonding materials required for their components is also facing increasingly stringent challenges.

[0003] At present, most of the assembly and fixation of power battery components use rivets, welding, traditional tapes and other methods. Rivet fixation requires drilling, which poses a risk of damaging battery components, and is prone to displacement, loosening and falling off due to wear during long-term use of the car. When welding, the welding temperature and time are difficult to accurately control. Too high a welding temperature or too long a time may cause thermal deformation or heat damage to battery parts, increase internal resistance and other problems. Power batteries are prone to thermal effects during the charging and discharging process. If traditional tapes do not have flame retardant properties, they are prone to spontaneous combustion, have low safety performance, and are not conducive to the long-term use of power batteries. In addition, solvents are added to thermosetting tapes during production, and residual solvents may remain during the curing process. The heat released by the battery will accelerate the volatilization of the residual solvent, which is harmful to the environment and the human body, and runs counter to the environmental protection concept that people are concerned about. Summary of the invention

[0004] In order to improve the above situation, the present invention provides a photocurable acrylic adhesive, characterized in that it comprises the following components in parts by weight, calculated on a solid weight basis:

[0005]

[0006] Furthermore, the UV acrylic resin A / B / C is a pre-polymerized UV acrylic polymer, which is polymerized by double bonds of one or more acrylic acid and its esters, wherein acrylic acid and acrylic acid esters include one or more monomers such as acrylic acid (AA), methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), methyl methacrylate (MMA), ethyl methacrylate (EMA), lauryl acrylate (LA), isooctyl acrylate (2-EHA), hydroxyethyl acrylate (HEA), benzyl methacrylate, and tridecyl acrylate. Among them, the UV acrylic resins A / B / C are mainly different in the main monomers used, the degree of polymerization, the molecular weight, etc.

[0007] Furthermore, the active diluent is one or more of monomers such as ethoxylated bisphenol A dimethacrylate, dipentaerythritol hexaacrylate, glycidyl methacrylate (GMA), dimethylaminoethyl methacrylate (DM), 1,6-hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (BPA-DA), ethylene glycol dimethacrylate (EGDMA), stearic methacrylate, 2-phenoxyethyl acrylate (PHEA), β-hydroxypropyl acrylate, and β-hydroxypropyl methacrylate.

[0008] Furthermore, the photoinitiator A is one or more of BASF Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 819, Irgacure 1300, Irgacure OXE01, Irgacure OXE02, and Darocur TPO.

[0009] Furthermore, the filler A / B is one or more of calcium carbonate, aluminum oxide, magnesium oxide, magnesium hydroxide, barium sulfate, silicon dioxide, boron nitride, aluminum hydroxide, and the like.

[0010] Furthermore, the filler C is one or more of calcium carbonate, silicon dioxide, hydrophobic fumed silica, hydrophilic fumed silica, glass microspheres, white carbon black, quartz powder, mica powder and the like.

[0011] Furthermore, the UV color paste is Clariant Hostatint UV Black N 30.

[0012] In addition, the present invention also provides a light-curable acrylic tape, characterized in that it comprises: a PE release red film 1 and a UV type acrylic resin adhesive layer 2. The thickness of the PE release red film 1 is 120 μm; the thickness of the UV type acrylic resin adhesive layer 2 is 1100 μm or 2300 μm.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. UV light curing technology is used for curing and molding. Unlike traditional thermosetting pressure-sensitive adhesives, it does not contain solvents and has a curing rate of up to 100%. This means that during the use of the tape, there will be no problem of residual solvent volatilization and discharge, which greatly reduces pollution to the environment and is highly consistent with the green environmental protection concept that the public is increasingly concerned about.

[0015] 2. One-piece molding and curing, without substrate in the middle. Compared with most multi-layer structure tapes with substrates on the market, the production thickness can be flexibly changed according to the application scenario, greatly reducing the production time cost.

[0016] 3. It has good bonding ability and can directly bond parts together, which can replace traditional mechanical connection methods such as rivets and welding to fix certain structural parts. There is no need to punch holes in the bonding parts, which avoids wear on the parts.

[0017] 4. After bonding the battery aluminum plate, the flame retardant grade can reach UL94 V-0, which has good flame retardant properties, can effectively reduce the risk of fire and improve the safety of use. The flame retardant filler used in the tape does not contain halogen, which greatly reduces the generation and release of harmful substances during use in heat and other environments, and is more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the curable acrylic tape provided by the present invention. DETAILED DESCRIPTION

[0019] Example 1

[0020]

[0021] UV acrylic resin A / B / C was mixed evenly at a ratio of 65:20:15, fillers A / B / C were added at a ratio of 50:20:10 and stirred evenly, and finally active diluent, photoinitiator and UV color paste were added and stirred evenly to obtain glue, and the finished acrylic tape was obtained by slit coating and UV light curing. The obtained product structure is an acrylic tape with a 120μm PE release red film and a thickness of 1100μm UV acrylic resin.

[0022] Example 2

[0023]

[0024] UV acrylic resin A / B / C was mixed evenly at a ratio of 55:20:25, fillers A / B / C were added at a ratio of 50:20:10 and stirred evenly, and finally active diluent, photoinitiator and UV color paste were added and stirred evenly to obtain glue, and the finished acrylic tape was obtained by slit coating and UV light curing. The obtained product structure is an acrylic tape with a 120μm PE release red film and a thickness of 1100μm UV acrylic resin.

[0025] Example 3

[0026]

[0027]

[0028] UV acrylic resin A / B / C was mixed evenly at a ratio of 65:20:15, fillers A / B / C were added at a ratio of 50:15:10 and stirred evenly, and finally active diluent, photoinitiator and UV color paste were added and stirred evenly to obtain glue, and the finished acrylic tape was obtained by slit coating and UV light curing. The obtained product structure is an acrylic tape with a 120μm PE release red film and a thickness of 1100μm UV acrylic resin.

[0029] Example 4

[0030]

[0031] UV acrylic resin A / B / C was mixed evenly at a ratio of 60:20:20, fillers A / B / C were added at a ratio of 50:20:10 and stirred evenly, and finally active diluent, photoinitiator and UV color paste were added and stirred evenly to obtain glue, and the finished acrylic tape was obtained by slit coating and UV light curing. The obtained product structure is an acrylic tape with a 120μm PE release red film and a thickness of 2300μm UV acrylic resin.

[0032] Example 5

[0033]

[0034] UV acrylic resin A / B / C was mixed evenly at a ratio of 68:20:12, fillers A / B / C were added at a ratio of 50:20:10 and stirred evenly, and finally active diluent, photoinitiator and UV color paste were added and stirred evenly to obtain glue, and the finished acrylic tape was obtained by slit coating and UV light curing. The obtained product structure is an acrylic tape with a 120μm PE release red film and a thickness of 2300μm UV acrylic resin.

[0035] Example 6

[0036]

[0037] UV acrylic resin A / B / C was mixed evenly at a ratio of 65:20:15, fillers A / B / C were added at a ratio of 40:20:10 and stirred evenly, and finally active diluent, photoinitiator and UV color paste were added and stirred evenly to obtain glue, and the finished acrylic tape was obtained by slit coating and UV light curing. The obtained product structure is an acrylic tape with a 120μm PE release red film and a thickness of 2300μm UV acrylic resin.

[0038] Comparative Example 1

[0039] In Comparative Example 1, the amount of UV type acrylic resin B added is 0, and the amounts of UV type acrylic resin A / C added are 85 parts and 15 parts respectively, and the rest are consistent with Example 1.

[0040] Comparative Example 2

[0041] In Comparative Example 2, the amount of filler A added is 0, and the amounts of filler B / C added are 50 parts and 10 parts respectively, and the rest are consistent with Example 1.

[0042] Comparative Example 3

[0043] In Comparative Example 3, the amount of filler B added is 0, and the amounts of filler A / C added are 50 parts and 10 parts respectively, and the rest are consistent with Example 1.

[0044] Performance Testing

[0045] The acrylic tapes prepared in the embodiments and comparative examples were subjected to performance tests. The specific test methods are as follows. The measured results are shown in Table 1.

[0046] (1) Thickness: Use a digital thickness gauge and test according to GB / T7125-2014 method.

[0047] (2) Hardness: Use a portable hardness tester and test in accordance with GB / T3969.3-2021 method.

[0048] (3) Probe initial adhesion: Use a probe initial adhesion tester and test according to ASTM / D2979-01 method.

[0049] (4) Ring initial adhesion: Use a computerized tension and pressure testing machine and test according to the GB / T31125-2014 method.

[0050] (5) Steel plate peeling force: Tested using a computerized tension and compression testing machine in accordance with the method of GB / T2792-2014.

[0051] (6) Shear force: Tested using a computerized tension and compression testing machine in accordance with the GB / T33332-2016 method.

[0052] (7) Holding force: Use a high temperature holding force test chamber and test according to GB / T4851-2014 method.

[0053] Table 1 - Properties of photocurable acrylic tapes prepared in Examples and Comparative Examples

[0054]

[0055]

[0056] In order to illustrate the key components in the present invention, Table 1 shows the key components. It can be seen from the measured results that the addition amount of UV type acrylic resin B in comparative example 1 is 0, the colloid is soft, and the test values ​​of various properties are relatively low compared with other examples; the addition amount of filler A in comparative example 2 is 0, filler B is 50 parts, and the addition amount of filler A in comparative example 3 is 50, filler B is 0 parts, both of which show that the colloid is soft, and the 70% compression strength and retention force are low. In Examples 1-6, when the colloid thickness is 1100μm, the peeling force and shear force of Example 1 are higher than those of Examples 2 and 3; the 30% and 50% compression strengths of Example 2 are high, and the 70% compression strength is low, and the compression strength in Example 3 is overall low. In Examples 1-6, the peeling force and shear force of Example 5 with a colloid thickness of 2300μm are higher than those of Examples 4 and 6; the 70% compression strength of Examples 4 and 6 are both low. In summary, when the colloid thickness is 1100 μm, Example 1 is better; when the colloid thickness is 2300 μm, Example 5 is better.

[0057] The above embodiments do not impose any limitation on the content of the composition of the present invention. Any slight modification, equivalent change and modification made to the above embodiments based on the technical essence or composition ingredients or content of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A photocurable acrylic adhesive, characterized in that: Calculated by solid weight, it includes the following components in parts by weight:

2. The photocurable acrylic adhesive according to claim 1, characterized in that The UV type acrylic resin A / B / C is a pre-polymerized UV type acrylic polymer, which is polymerized by double bonds of one or more acrylic acid and its esters, wherein acrylic acid and acrylic esters include one or more of acrylic acid (AA), methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), methyl methacrylate (MMA), ethyl methacrylate (EMA), lauryl acrylate (LA), isooctyl acrylate (2-EHA), hydroxyethyl acrylate (HEA), benzyl methacrylate, and tridecyl acrylate monomers, and the main monomers, polymerization degrees and molecular weights used in the UV type acrylic resins A / B / C are all different.

3. The photocurable acrylic adhesive according to claim 1, characterized in that The active diluent is one or more of ethoxylated bisphenol A dimethacrylate, dipentaerythritol hexaacrylate, glycidyl methacrylate (GMA), dimethylaminoethyl methacrylate (DM), 1,6-hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (BPA-DA), ethylene glycol dimethacrylate (EGDMA), stearic methacrylate, 2-phenoxyethyl acrylate (PHEA), β-hydroxypropyl acrylate, and β-hydroxypropyl methacrylate monomers.

4. The photocurable acrylic adhesive according to claim 1, characterized in that The photoinitiator A is one or more of BASF Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 819, Irgacure 1300, IrgacureOXE01, Irgacure OXE02, and Darocur TPO.

5. The photocurable acrylic adhesive according to claim 1, wherein The filler A / B is one or more of calcium carbonate, aluminum oxide, magnesium oxide, magnesium hydroxide, barium sulfate, silicon dioxide, boron nitride, and aluminum hydroxide.

6. The photocurable acrylic adhesive according to claim 1, characterized in that The filler C is one or more of calcium carbonate, silicon dioxide, hydrophobic fumed silica, hydrophilic fumed silica, glass microspheres, white carbon black, quartz powder, and mica powder.

7. The photocurable acrylic adhesive according to claim 1, characterized in that The UV color paste is Clariant Hostatint UV Black N 30.

8. An adhesive tape prepared from a photocurable acrylic adhesive according to any one of claims 1 to 7, characterized in that: include: PE release red film 1, UV type acrylic resin adhesive layer 2, wherein the thickness of the PE release red film 1 is 120 μm; The thickness of the UV type acrylic resin adhesive layer 2 is 1100 μm or 2300 μm.

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