Acrylic pressure sensitive adhesive for microwave door stickers

Ordinary microwave oven door paste is made of transparent polyester film with a thickness of 0.1mm coated with acrylic solvent pressure-sensitive adhesive after drying and releasing polyester film composite, the final die-cutting molding. The appearance requirements of microwave oven door stickers are transparent and clear, and there should be no scratches, bruises, bubbles, and other undesirable phenomena on the surface. The physical property index is 90° peeling strength ≥10N/25mm. Temperature resistance 180℃ (the surface coated with solvent pressure sensitive adhesive polyester film on the microwave door plate in 180℃ environment after heating for 30 minutes, the appearance of the door paste shall not turn yellow, or warped, clarity shall not weaken, distance 1 foot can see the word typeface 4).

High-temperature microwave oven door sticker should be able to withstand 210℃. Microwave oven door paste technical requirements whether appearance or physical indicators single look is not difficult to do, there are a lot of adhesives on the market that can meet the requirements, but comprehending all indicators to meet the requirements is very difficult, with clarity, peel strength and can not reach, vice versa. Although the existing adhesive formula can meet the above basic requirements, the shrinkage rate is large, and can only withstand the temperature of 180℃, only suitable for ordinary microwave ovens, 210℃ baking door paste will still occur warping, fuzzy, and peeling strength reduction phenomenon.

This paper provides a preparation method for acrylic pressure-sensitive adhesive for microwave door pasting. The steps include: (1) adding the viscous monomer, cohesive monomer, modified monomer, crosslinking agent, solvent, and emulsifier into the reaction reactor, stirring and heating up to 85±2℃, holding temperature 1.5 h; (2) Cool the reactor to 75±2℃, then add 1/3 weight part of the initiator, heating reaction for 3-6h, three times continue to add the remaining 2/3 weight part of the initiator, each drop interval time is 0.5 h, reaction 1-2h after dropping, then reduce the temperature to 60℃; (3) Pour defoaming agent, leveling agent and wetting agent into the system of step (2), stir for 30-60min, and then cool down to 40 ℃ for filtration to obtain the acrylic pressure sensitive adhesive.

Beneficial effects: The acrylic pressure-sensitive adhesive for microwave oven door paste prepared by the invention can maintain the basic performance and at the same time make the product have good shrinkage, meet the appearance requirements of all the polyester film door paste for microwave oven, and the rear door paste will not warping, fuzzy, peeling strength reduction and other phenomena after baking at 210℃, so it is very suitable for high-temperature microwave oven such as barbecue microwave oven.