Influence of Acrylic Acid on Kinetics of UV-Induced Cotelomerization Process and Properties of Obtained Pressure-Sensitive Adhesives

Abstract

A new environmentally friendly method of photoreactive pressure-sensitive adhesives (PSAs) preparation was demonstrated. PSAs based on n-butyl acrylate (BA), acrylic acid (AA) and 4-acryloyloxy benxophenone (ABP) were prepared via the UV-induced cotelomerization process in the presence of a radical photoinitiator (acylphosphine oxide) and telogen (tetrabromomethane). Hydroxyterminated polybutadiene was used as a crosslinking agent. Influence of AA concentration (0–10 wt %) on kinetics of the cotelomerization process was investigated using a photodifferential scanning calorimetry method, selected physicochemical features of obtained photoreactive BA/AA/ABP cotelomers (molecular masses, polydispersity, monomers conversion and dynamic viscosity) and self-adhesive properties of obtained PSAs (adhesion, tack and cohesion) were studied, as well. It turned out that AA content is the important factor that influences monomers conversion (thereby the volatile parts content in prepolymer) and PSAs’ properties. As the acrylic acid content increases, the reaction rate increases, but the total monomers conversion and the solid content of the prepolymer decreases. Additionally, the adhesion and cohesion of PSAs were grown up, and their tackiness decreased. However, the AA content has no effect on molecular weights (Mw and Mn) and polydispersity (c.a. 1.5) of photoreactive cotelomers. The optimal AA content necessary to obtain a prepolymer with low volatile parts content and good PSA properties was determined.

Adhesive Films Based on Benzoxazine Resins and the Photoreactive Epoxyacrylate Copolymer

“…The UV-cross-linking process in SATs is possible because the EAC contains photoreactive benzophenone groups (from type II photoinitiator, i.e., ABP). The mechanism of cross-linking of ABP-containing polyacrylate chains is known from the literature [ 38 ]. As can be seen, both SATs before the UV-cross-linking process show high adhesion to steel (32 N/25 mm for SAT-B7 and 43 N/25 mm for SAT-B9) but the cohesive failures effects are visible.…”

The Effect of Type-I Photoinitiators on the Kinetics of the UV-Induced Cotelomerization Process of Acrylate Monomers and Properties of Obtained Pressure-Sensitive Adhesives

“…The structures of photoinitiators are shown in Table 1 .The components were applied without purification. A hydroxyl-terminated polybutadiene resin Hypro 1200X90 HTB (CVC Thermoset Specialties, Emerald Kalama Chemical, Kalama, WA, USA) as a multifunctional monomer of the UV-crosslinking process was used, as previously reported [ 27 ].…”

“…This article is a continuation of the recent research presented on a new solvent-free method of PSA preparation for various applications [ 27 ], i.e., UV-induced cotelomerization process. Telomerization is a reaction of a polymerizable compound (M) in the presence of a chain transfer agent (YZ), which is provided to macromolecules Y (M) n Z, where n is less than 100 but is not 1 [ 28 ].…”

Adhesion Improvement of Solvent-Free Pressure-Sensitive Adhesives by Semi-IPN Using Polyurethanes and Acrylic Polymers

“…Although rubber PSAs generally have excellent adhesion properties, they suffer from low oxidative resistance [ 11 ]. Acrylic PSAs are mainly synthesized from random copolymers containing monomers with low (butyl acrylate and 2-ethylhexyl acrylate) and high (methyl methacrylate and isobornyl acrylate) glass transition temperatures (T g ) [ 9 , 12 ]. Acrylic PSAs require chemical crosslinking because of their low cohesive strength, and they have the advantages of high transparency, water resistance, and controllable adhesive properties [ 6 , 13 , 14 ].…”