Actinic radiation-initiated epoxy adhesive and articles made therefrom

Abstract

There is provided a one part, actinic radiation-activated, and room temperature curable epoxy-based adhesive. There is also provided an adhesive initiator system based on an iodonium salt combined with a thioxanthone photosensitizer such as isopropyl thioxanthone. There are also provided methods of use and articles made using such one part, actinic radiation-activated, and room temperature curableepoxy-based adhesive comprising an adhesive initiator system comprising an iodonium salt combined with a thioxanthone photosensitizer.

Description

technical field

[0001] The present disclosure relates to actinic radiation-initiated epoxy adhesives, methods of using such adhesives, and articles made therefrom. Background technique

[0002] As designs become more complex, manufacturers such as consumer electronics makers, appliance makers, vehicle builders, and more are increasingly switching from tapes to liquid adhesives for product assembly. For example, the rise of larger display areas, curved surfaces, and a variety of material options necessitates alternatives to traditional foam or double-sided tape. Hot melt moisture cure polyurethane adhesives have recently become the primary solution for these bonding needs. These adhesives generally provide very good shear and impact properties, quick handling strength, do not require precision mixing, and allow automated device assembly. However, polyurethane adhesives typically have a very short open time, which inhibits soak-through and sticking, have poor pot life, and r...

Examples

Embodiment 1-6 and comparative example A-F

[0024] For each of the following examples and comparative examples, an approximately 2 mm thick bead of adhesive was dispensed in a 1 inch wide bead using an EFD 1500XL DISPENSER from Nordson EFD, Westlake, Ohio. Measure the entire width of a clear polycarbonate (PC) plastic coupon 4 inches long. Immediately after dispensing, the coupons were placed on the conveyor of the FUSION UV CURING SYSTEM available from Fusion UV Systems Inc., Gaithersburg, Maryland, using a D-type bulb The low intensity mercury vapor lamps expose them to various levels of UV-A energy. Total UV-A (320 nm to 390 nm) energy was measured using a UV POWER PUCK II radiometer from EIT Inc., Sterling, Virginia. The total energy exposure is varied by adjusting the conveyor speed. Immediately after 1 second of UV exposure, a 1-inch by 4-inch PC coupon was placed on top of the bead-coated surface of the first coupon, and was obtained using Eunsung Industrial Co., Ltd., Ansan, Korea. Industrial Co., Ltd., Ansan...

Embodiment 7-14 and comparative example G-N

[0029]Examples 7-14 and Comparative Examples G-N were prepared as described in Examples 1-6 and Comparative Examples A-F, with the following modifications. UV-A exposure was fixed at 2.5 J / cm2 and the time elapsed before coupon bonding was varied. The results are reported in Table 4.

[0030] Table 4

[0031]

Embodiment 15-22 and comparative example O-V

[0033] Examples 15-22 and Comparative Examples O-V were prepared as described in Examples 1-6 and Comparative Examples A-F, with the following modifications. UV-A exposure was fixed at 1.0 J / cm2 and the time elapsed before coupon bonding was varied. The results are reported in Table 5.

[0034] table 5

[0035]

technical field

[0001] The present disclosure relates to actinic radiation-initiated epoxy adhesives, methods of using such adhesives, and articles made therefrom. Background technique

[0002] As designs become more complex, manufacturers such as consumer electronics makers, appliance makers, vehicle builders, and more are increasingly switching from tapes to liquid adhesives for product assembly. For example, the rise of larger display areas, curved surfaces, and a variety of material options necessitates alternatives to traditional foam or double-sided tape. Hot melt moisture cure polyurethane adhesives have recently become the primary solution for these bonding needs. These adhesives generally provide very good shear and impact properties, quick handling strength, do not require precision mixing, and allow automated device assembly. However, polyurethane adhesives typically have a very short open time, which inhibits soak-through and sticking, have poor pot life, and r...

Examples

Embodiment 1-6 and comparative example A-F

[0024] For each of the following examples and comparative examples, an approximately 2 mm thick bead of adhesive was dispensed in a 1 inch wide bead using an EFD 1500XL DISPENSER from Nordson EFD, Westlake, Ohio. Measure the entire width of a clear polycarbonate (PC) plastic coupon 4 inches long. Immediately after dispensing, the coupons were placed on the conveyor of the FUSION UV CURING SYSTEM available from Fusion UV Systems Inc., Gaithersburg, Maryland, using a D-type bulb The low intensity mercury vapor lamps expose them to various levels of UV-A energy. Total UV-A (320 nm to 390 nm) energy was measured using a UV POWER PUCK II radiometer from EIT Inc., Sterling, Virginia. The total energy exposure is varied by adjusting the conveyor speed. Immediately after 1 second of UV exposure, a 1-inch by 4-inch PC coupon was placed on top of the bead-coated surface of the first coupon, and was obtained using Eunsung Industrial Co., Ltd., Ansan, Korea. Industrial Co., Ltd., Ansan...

Embodiment 7-14 and comparative example G-N

[0029]Examples 7-14 and Comparative Examples G-N were prepared as described in Examples 1-6 and Comparative Examples A-F, with the following modifications. UV-A exposure was fixed at 2.5 J / cm2 and the time elapsed before coupon bonding was varied. The results are reported in Table 4.

[0030] Table 4

[0031]

Embodiment 15-22 and comparative example O-V

[0033] Examples 15-22 and Comparative Examples O-V were prepared as described in Examples 1-6 and Comparative Examples A-F, with the following modifications. UV-A exposure was fixed at 1.0 J / cm2 and the time elapsed before coupon bonding was varied. The results are reported in Table 5.

[0034] table 5

[0035]

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