Butyl acrylate/4-acryloyloxy benzophenone copolymers as photoreactive UV-crosslinkable pressure-sensitive adhesives
It has previously been shown that copolymers of butyl acrylate with 4-acryloyloxy benzophenone can be used as pressure-sensitive adhesives (PSAs). This paper presents the synthesis and application of a solvent-borne polymer system for the preparation of photoreactive UV-crosslinkable acrylic pressure-sensitive adhesives. Butyl acrylate/benzophenone copolymers with molecular mass in the range 180 000 to 480 000 Dalton were prepared by carrying out free-radical solution polymerization. These copolymers were found to be tacky but in some cases to possess insufficient cohesive strength after UV-crosslinking to be useful as PSAs. The other copolymers resulted in materials with the balance of cohesive and adhesive characteristics required of good PSAs. Some of the parameters affecting the pressure-sensitive adhesive properties of the copolymers are the concentration of 4-acryloyloxy benzophenone, the molecular mass of the polymeric components, the UV-reactivity, and properties such as tack, peel adhesion, and cohesion.
Oxidation of hexafluoropropylene to hexafluoropropylene oxide using oxygen
A method for pressure oxidation of hexafluoropropylene (HFP) to hexafluoropropylene oxide (HFPO), using oxygen, is presented. Oxidation was achieved in a batch-fed reactor at temperature range between 130 to 170°C. The influence of temperature and kind of solvents, such as 1,2,2-trichloro-1,1,2-trifluoroethane (CFC-113) and carbon tetrachloride on the yield of HFPO and the course of oxidation was investigated in preliminary studies. The maximum HFPO yield of approximately 83% was noticed.
UV-crosslinkable warm-melt pressure-sensitive adhesives based on acrylics
The target of this article is to show the preparation of new generation of UV-crosslinkable warm-melt acrylic pressure-sensitive adhesives (PSAs) and the experimental test of their adhesive properties in comparison with typical conventional hot-melts adhesives. New generation of UV-crosslinkable acrylic warm-melts PSAs containing unsaturated photoinitiator, incorporated during polymerization process into polymer chain, and photoreactive diluents added to PSA systems after polymerization allows producing of wide range of self-adhesive materials, such as labels, mounting tapes, masking and splicing tapes, and sign and marking films.
Polyurethane pressure-sensitive adhesives as raw materials for the manufacturing of protective films
The present paper relates to water-borne polyurethane pressure-sensitive adhesives (PU-PSA) systems for self-adhesive protective films, and methods of their preparation. The typical protective films are self-adhesive films with excellent removability. Their manufacture is a film conversion process using common materials developed for the packaging industry (PVC and polyolefins). The most often used carrier for the constructions of protective films is PE. Polyurethane PSA layers are characterized by constant low peel adhesion between 3 and 5 N/2,5 cm.
Development of photoreactive UV-crosslinkable solvent-free acrylic pressure-sensitive adhesives coated at room temperature and used for removable and repositionable self-adhesive materials
The goal of this article is to review the development of photoreactive UV-crosslinkable acrylic pressure-sensitive adhesives (PSAs) characterized by low viscosity, which can be coated at room temperature in the form of adhesive layers and are characterized by removable properties after UV-crosslinking. Surfactants and stearic acid have been used to improve the performance of the acrylic PSA, too. They are used for the manufacturing of removable and repositionable self-adhesive products, such as easy peel-able decorative films and wide range version of post-it articles.
Jolanta Świderska, Zbigniew Czech and Agnieszka Kowalczyk
Typical commercial restorative dental compositions in the form of medical resins contain in-organic fillers, multifunctional methacrylates and photoinitiators. The currently used resins for direct composite restoratives have been mainly based on acrylic chemistry to this day. The main problem with the application and radiation curing process is the shrinkage of photoreactive dental materials during and after UV curing. Shrinkage of restorative radiation curable dental composites is a phenomenon of polymerization shrinkage, typical behavior of multifunctional methacrylates during the polymerization process. The important factors in curing of dental composites are: the kind and concentration of the used methacrylate, its functionality, double bond concentration, the kind and concentration of the added photoinitiator and UV dose emitted by the UV-lamp. They are investigated multifunctional 1,3-butanediol dimethacrylate (1,3-BDDMA), diethylene glycol dimethacrylate (DEGDMA), triethylene glycol dimethacrylate (TEGDMA), trimethylolpropane trimethacrylate (TMPTMA), 2,2-bis-[4-(2-hydroxy-3-methacryxloyloxypropyl) phenyl]propane (Bis-GMA), ethoxylated Bis-GMA (EBPDMA) and dodecandiol dimethacrylate (DDDMA). Reduction of polymerization shrinkage of restorative dental compositions is at the moment a major problem of dental technology. This problem can be solved through an application of photoreactive non-tacky multifunctional methacrylates in the investigated dental adhesive fillings.
Thermal degradation of poly(alkyl methacrylates) and polyurethane pressure-sensitive adhesives
Gas chromatography, coupled with the temperature controlled pyrolysis technique, can be used as a quick method of identification of polymers such as acrylates, methacrylates and polyurethanes. Polymers based on alkyl methacrylates are widely used as construction materials and coatings. Polyurethanes are widely used as self-adhesives, sealants and electrical products (due to polyurethane's low glass transition temperature Tg). The aim of this work is to investigate which products can be obtained from polymethacrylates and polyurethanes.
Roland Milker, Zbigniew Czech and Marta Wesołowska
Synthesis of photoreactive solvent-free acrylic pressure-sensitive adhesives in the recovered system
The present paper discloses a novel photoreactive solvent-free acrylic pressure-sensitive adhesive (PSA) systems, especially suitable for the so much adhesive film applications as the double-sided, single-sided or carrier-free technical tapes, self-adhesive labels, protective films, marking and sign films and wide range of medical products. The novel photoreactive solvent-free pressure-sensitive adhesives contain no volatile organic compounds (residue monomers or organic solvent) and comply with the environment and legislation. The synthesis of this new type of acrylic PSA is conducted in common practice by solvent polymerisation. After the organic solvent are removed, there remains a non-volatile, solvent-free highly viscous material, which can be processed on a hot-melt coating machine at the temperatures of about 100 to 140°C.
Thermal decomposition of acrylic pressure-sensitive adhesives
The general aim of this article is to review the state of knowledge on pressure-sensitive adhesives (PSAs) and pyrolysis. Recent research data in the field of pyrolysis gas- chromatography (Py-GC) analysis of acrylic PSAs are presented. First, PSA characteristics and applications, pyrolysis (including Py-GC) as an analytical method, and system solutions, are described. The latest scientific achievements in the analysis of thermal degradation products of acrylic PSAs are then presented.
Zbigniew Czech, Zbigniew Maciejewski and Krystyna Kondratowicz-Maciejewska
The application of water-borne pressure-sensitive adhesives (PSA) based on acrylics is increasing in a variety of industrial areas. The have been used for manufacturing of double sided and carrier free mounting tapes, splicing tapes, marking and sign films, self-adhesive labels, packaging tapes, protective films and diverse high quality medical materials. Nano-sized inorganic fillers can modify diverse adhesive and self-adhesive coating properties such as tack, peel adhesion, shear strength at 20°C and 70°C, and removability Amorphous synthetic silica nanoparticles in form of water dispersions: Ludox PX-30 (30 wt.% silica stabilizing with counter ion sodium), Ludox PT-40 (40 wt.% silica stabilizing with counter ion sodium), Ludox PT-40AS (40 wt.% silica stabilizing with counter ion ammonium), and Ludox PW-50 (50 wt.% silica stabilizing with counter ion sodium) (from Grace) in concentrations between 1 and 5wt.% were used for modifying of water-born pressure-sensitive adhesive acrylics: Acronal 052, Acronal CR 516 (both BASF) and Plextol D273 (Synthomer) properties. It has been found in this study that the nano-technologically reinforced system containing of Acronal 052 and amorphous silica Ludox PX-30 showed a great enhancement in tack, peel adhesion and shear strength. In this paper we evaluate the performance of Acronal 052 modified with amorphous silica Ludox PX-30.