Self-Crosslinkable Pressure-Sensitive Adhesives from Silicone-(Meth)acrylate Telomer Syrups

Abstract

In this study, a novel and environmentally friendly method for the preparation of photoreactive pressure-sensitive adhesives (PSAs) was demonstrated. Adhesive binders based on n-butyl acrylate, methyl methacrylate, acrylic acid, and 4-acryloyloxy benzophenone were prepared with a UV-induced telomerization process in the presence of triethylsilane (TES) as a telogen and acylphosphine oxide (APO) as a radical photoinitiator. The influence of TES (0–10 wt. parts) and APO (0.05–0.1 wt. parts/100 wt. parts of monomer mixtures) concentrations on the UV telomerization process kinetics was investigated using a photodifferential scanning calorimetry method and selected physicochemical features of the obtained silicone-(met)acrylate telomeric syrups (K-value, solid content, glass-transition temperature, and dynamic viscosity), as well as properties of the obtained PSAs (Tg, adhesion, tack, and cohesion), were studied. An increase in TES content caused a significant decrease in the Tg values (approx. 10 °C) and K-value (up to approximately 25 a.u.) of the dry telomers, as well as the dynamic viscosity of the telomeric syrups. PSAs were obtained through UV irradiation of thin polymer films consisting only of silicone-(meth)acrylate telomer solutions (without the use of additional chemical modifiers or of a protective gas atmosphere and protective layers). PSAs were characterized by very good adhesion (12.4 N/25 mm), cohesion at 20 °C (>72 h) and 70 °C (>72 h), and low glass-transition temperature (−25 °C).

Influence of Talc on the Properties of Silicone Pressure-Sensitive Adhesives

“…This phenomenon is commonly observed in self-adhesive technologies containing fillers [23,24]. The conventional acceptable limit for adhesion and stickiness, where it is assumed that the tested material can be used as an adhesive tape, is 10 N/25 mm and 8 N, respectively [25]. Only for 3 pph of filler, the samples did not meet the limit values for stickiness.…”

Functional Acrylic Resins Prepared via Photo-Induced Telomerization Using Tetrabromomethane as Telogen

“…A relatively novel method for obtaining functional acrylic resins is telomerization [24,25]. It is a chain reaction of monomer(s) and telogen in polymerization conditions, but the products are polymers/oligomers with relatively low molecular weight and dispersity [26].…”