RESUMEN
The article describes new silicone self-adhesive adhesives modified with the addition of talc. The obtained self-adhesive materials were characterized to determine their adhesive properties (adhesion, cohesion, and adhesion) and functional properties (pot life of the composition, shrinkage, and thermal properties of adhesives). Novel materials exhibited high thermal resistance above 225 °C while maintaining or slightly reducing other values (adhesion, cohesion, shrinkage, and tack). Selected composition: T 0.1 was used to prepare self-adhesives in industrial-scale production. Moreover, conducted test results revealed that the addition of talc delayed the thermal decomposition of the adhesive and provided reduced intensity of smoke emissions during combustion as well as the flammability of the adhesive layer.
RESUMEN
This publication describes the influence of residue monomers in synthesized pressure-sensitive adhesives based on acrylics on their main properties-tack, peel adhesion, shear strength and shrinkage-in the form of transfer tapes used for joining wooden elements in the furniture industry. The discussed carrier-free adhesive tapes are synthesized via photo-crosslinking and photopolymerization with UV radiation of the photoreactive prepolymers sandwiched between two adhesive siliconized polyester films. The simultaneous crosslinking and polymerization processes carried out under UV lamps placed simultaneously above and below the crosslinked photoreactive polymer layer lead to the production of a carrier-free adhesive film. The preliminary target of these studies was to investigate how the intensity of UV radiation and the time of its exposure affect the viscosity of the photoreactive compositions and the content of unreacted monomers in them. Next, the influence of the crosslinking agent concentration and UV irradiation time on the content of unreacted monomers after the crosslinking process was tested. The last step of the studies was the investigation of the influence of the residue monomer concentration on the application properties of the obtained pressure-sensitive adhesive layers. The typical PSA application properties were tested on the wood samples: tack, peel adhesion, shear strength (cohesion) and shrinkage.
RESUMEN
The properties of solvent-based pressure-sensitive adhesive (PSA) acrylics, especially shrinkage, are mostly determined by the type and amount of the crosslinking agent added to the prepolymer or by the crosslinking method. The shrinkage profiles of the selected solvent-based acrylic PSA coated on PVC film were investigated using metal chelates (between 0 and 0.55 wt.%), N-methylol acrylamide (up to 8 wt.%), polycarbodiimide and amino resins (up to 6 wt.%), diisocyanate (up to 1 wt.%), multi-functional propylene imines (up to 0.9 wt.%), conventional photoinitiators (up to 3 wt.%) and copolymerizable photoinitiators (up to 2 wt.%). These chemicals were both crosslinking agents that react after the solvent has been evaporated or at higher temperatures, and to the crosslinking agents that react under UV radiation. Some of them were copolymerizable, and others were added to the prepolymer before crosslinking. The best results of shrinkage (0.2%) were obtained by using the UV-crosslinking method and copolymerizable photoinitiators ZLI 3331 and ABP, as well as metal chelates AlACA and TiACA and multifunctional propylene imine Neocryl CX-100 (0.2%). Acceptable results were also achieved for amide BPIA (0.3%), benzophenone derivative PCB (0.4%), N-methylol acrylamide (0.35%) and benzoguanamine resin Cymel 1123 (0.45%).
RESUMEN
The use of ultraviolet radiation (UV) technology for the crosslinking of acrylic pressure-sensitive adhesives (PSA) is the one of various crosslinking methods, being the alternative to the conventional crosslinking process of solvent-based acrylic systems. It also requires a photoinitiator to absorb the impinging UV and induce photocrosslinking. As previously mentioned, a photoinitiator is one of the important and necessary components in UV-inducted crosslinking of acrylic pressure-sensitive adhesives. The activity of multifunctional conventional saturated photoinitiators of type I and type II, especially benzophenone-based in the photoreactive UV-crosslinkable acrylic PSA was described. The effect of the multifunctional type-II photoinitiators on the acrylic PSA, such as tack, peel adhesion and shear strength were summarized.
RESUMEN
In this study, syntheses of acrylate copolymers were performed based on the monomers butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA), and acrylic acid (AA) and the second-type unsaturated photoinitiator 4-acryloyloxybenzophenone (ABP). The structure of the obtained copolymers was confirmed via FT-IR spectroscopic analysis, and the viscosity and the content of non-volatile substances were determined. The adhesive films were then coated and cross-linked using ultraviolet radiation in the UV-C range at various doses (5-50 mJ/cm2). Due to the dependence of the self-adhesive properties of the adhesive layer on the basis weight, various basis weights of the layer in the range of 30-120 g/m2 were tested. Finally, the self-adhesive properties were assessed: tack, peel adhesion, shear strength (cohesion) at 20 °C and 70 °C, as well as the SAFT test and shrinkage. The aim of the study was to determine the effect of the type of monomer used, the dose of ultraviolet radiation, and the basis weight on the self-adhesive and usable properties of the obtained self-adhesive tapes.
RESUMEN
A new class of additionable ultraviolet photoinitiators that can be used, through addition, for modification of the acrylic polymer chain and their influence of main properties of acrylic pressure-sensitive adhesives (PSAs) is described here. The photoinitiators studied are based on benzophenone, dibenzofuran and anthraquinone chromophores. The propyleneimine carbonyl is the reactive additionable group incorporated in the photoinitiator structure. First, the solvent-borne acrylic pressure-sensitive adhesive was synthesized and characterized. Then, a photoinitiator suitable for addition to the acrylic polymer chain possessing a carboxyl group was added before UV-irradiation. A mechanism of UV-initiated cross-linking reaction of acrylic PSA with additionable photoinitiators was done as well. The influence of the concentration and type of photoinitiator, UV-crosslinking time and UV-dose on peel adhesion, shear strength and tack of solvent-borne acrylic pressure-sensitive adhesives cross-linked by UV light was studied and presented here. It was found that the tack depends on the UV-dose and photoinitiator concentration. An increase of UV dose results in an increase of shear strength of acrylic pressure-sensitive adhesive (PSA) formulations.
RESUMEN
The ammonolysis of waste 1,2-dichloropropane (DCP) using liquid ammonia has been investigated. The influence of temperature, molar ratio of NH3/1,2-dichloropropane and reaction time was examined. The highest yield of the synthesis was achieved at a temperature of 140 degrees C, for the reaction time of 3 h and the molar ratio of NH3/1,2-dichloropropane as 20:1. Under these conditions the degree of 1,2-dichloropropane conversion amounted to 97.1 mol% and the selectivity of transformation to 1,2-diaminopropane (DAP) in relation to consumed 1,2-dichloropropane was 25.3 mol%, whereas in relation to consumed ammonia 17.9 mol%. The remaining 1,2-dichloropropane reacts to form polypropyleneamines.