Publikace detail

Rheological characterization of hot melt adhesives based on EVAK copolymers

Autoři: Šiška Bedřich | Machač Ivan | Balcar Miroslav | Vrána Jiří

Rok: 2014

Druh publikace: ostatní - článek ve sborníku

Název zdroje: AERC 2014 - Book of abstracts

Název nakladatele: Deutsche Rheologische Gesellschaft (DRG)

Místo vydání: Karlsruhe

Strana od-do: 175

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
eng	Rheological characterization of hot melt adhesives based on EVAK copolymers	The results of measurements of rheological properties of five hot melt compositions based on polyvinyl acetate-polyethylene copolymer are presented. The compositions tested differ in the content of tackifying resins. Their properties were studied under the steady shear and dynamic conditions (DMA analyser, Haake MARS rheometer). From the DMA, the glass transition temperatures of compositions were determined. The measurements of flow curves, oscillatory, creep&recovery, and tack tests of melted samples were performed in the temperature range of 120-180◦ C. It was found that all the melts tested behave as slightly shear thinning and thixotropic fluids. The viscosities, degree of shear thinning, and thixotropy decrease with the increasing temperature. Due to the wax and resin content, the viscosity of the compositions is significantly lower than that of the basic EVAK components. A semi-empirical equation was proposed for the estimation of composition viscosities. From the oscillatory tests, the storage modulus G’, loss modulus G”, and complex viscosity were evaluated. At lower values of frequency, loss modulus prevails, which predicates that the wetting and adhesive flows can be sufficient to form good contact with the substrate. The results of creep and recovery tests document that the melts exhibit only insignificant degree of linear elasticity at the measurement conditions. The tack was estimated according to the maximum magnitude of the normal force reached in the test. It was verified that this force increases with the increasing speed of lifting and decreasing temperature (increasing melt viscosity). The rheological behaviour of the all compositions tested is not significantly influenced by the kind of tackifying resin and its content in the studied limits.	Rheology; hot melt adhesives; EVAK copolymers; DMA

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