[article]
Titre : |
Taking the pressure out of formulating pressure-sensitive adhesives |
Type de document : |
texte imprimé |
Auteurs : |
Hitesh Soni, Auteur |
Année de publication : |
2016 |
Article en page(s) : |
p. 28-30 |
Note générale : |
Bibliogr. |
Langues : |
Anglais (eng) |
Catégories : |
Adhésifs -- Additifs Adhésifs sensibles à la pression AziridineL'aziridine (n.f.) ou azacyclopropane est le composé organique cyclique de formule brute C2H5N. Elle est aussi le composé parent des aziridines et du groupe fonctionnel qui correspond à un hétérocycle à trois côtés composé d'une amine et de deux groupes méthylène. Cisaillement (mécanique) Epoxydes Essais d'adhésion Essais de pelage Polyacryliques Polymères hydrosolubles Réticulants
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Index. décimale : |
668.3 Adhésifs et produits semblables |
Résumé : |
A new tetrafunctional epoxy reactive modifier is increasingly use as a non-mutagenic, drop-in replacement for polyfunctional aziridine in adhesives and coatings formulations.
Industrial coatings and adhesives formulations often rely on crosslinkers to boost key performance properties, such as strength, wear and chemical resistance. This is especially so in two-component (2K) systems, where crosslinkers are a critical part of the 2K package. While crosslinkers greatly enhance the performance in the end product, they can also present formulating challenges - processing, pot-life or health and safety concerns - and newer alternatives have been developed to address these needs.
Formulating pressure-sensitive adhesives (PSAs) presents a number of complex challenges. The adhesive must flow and set without activation from anything more than the pressure of a hand, remain permanently tacky, exhibit a strong bond - often to a variety of substrates, such as wood, glass or metal for as long as the application requires or until the end user decides to remove it. Once removed, the PSA must exhibit the necessary cohesive strength that it can be easily removed without leaving adhesive residue behind.
The wide span of tapes, labels, protective films and more that use this technology, rely on an effective crosslinker to achieve many of their key performance properties, including cohesion, shear strength, chemical resistance, performance at high or low temperatures and peel adhesion.
Poiyfunctional aziridine is a common choice as a crosslinker in many waterborne PSAs and coatings formulations due to its efficacy and economy. However, polyfunctional aziridine has recently come under fire in both the USA and EU markets, due to its status as a potentiel mutagen. Its reduced efficacy over relatively short dwell times in water is also a concern ; the net effect can lead to a variation in adhesive properties, as well as problems with manufacturing efficiency. These challenges have added to the concerns that a PSA formulator must consider and lead to a growing need for a crosslinker option that is less hazardous to human health, more stable over time and can also offer the same or greater hardness and shear adhesion for adhesive formulations. One alternative, which has been demonstrated as an effective drop-in replacement, is a new tetra-glycidyl m-xylene diamine (ERISYS® GA-240), a tetrafunctional epoxy reactive modifier. |
Note de contenu : |
- Formulation
- Testing and results : Peel adhesion - Shear adhesion
- FIGURES : 1. Polymer chain of water-soluble, acrylic PSAs - 2. Increasing molecular weight will result in improved cohesive strength and shear adhesion along with decreased peel adhesion and tack - 3. Typical structures for a polyfunctional aziridine and ERISYS GA-260 epoxidised metaxylenediamine crosslinkers - 4. Instron machine was used to measure peel adhesion - 5. Above : Results of peel adhesion testing with the new tetra-glycidyl m-xylene diamine reactive modifier - 6. Above right : results of peel adhesion testin gwith a polyfunctional aziridine crosslinker - 7. To test shear adhesion, tape coated with the PSA is affixed to a stainless steel plate and a weight suspended from it - 8. Below : use of the new tetra-glycidyl m-xylene diamine (right) resulted in improved cohesive strength and little to no adhesive transfer compared to control (left) - 9. Shear adhesion, one-day cure at RT (at higher crosslinker levels results exceed 3100 min) - 10. Shear adhesion, three-day cure at RT (at higher crosslinker levels results exceed 3100 min) - 11. Shear adhesion, five-day cure at RT (at higher crosslinker levels results exceed 3100 min) |
En ligne : |
https://drive.google.com/file/d/1wY7MJaLdEBbC52C7FSLheRzpbfSf_wMQ/view?usp=drive [...] |
Format de la ressource électronique : |
Pdf |
Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27741 |
in POLYMERS PAINT COLOUR JOURNAL - PPCJ > Vol. 206, N° 4624 (09/2016) . - p. 28-30
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