Poliuretanski premazi za les iz utekočinjenega lesa : diplomsko delo - univerzitetni študij

Bradeško, Davorin (author), Petrič, Marko (mentor), Poljanšek, Ida (reviewer)

Potreba po proizvodih, narejenih iz obnovljivih virov, v sodobnem svetu vse bolj narašča. Utekočinjen les (UL) je dokaj nova obnovljiva surovina, katero je možno uporabiti tudi za izdelavo poliuretanskih premaznih sredstev. Topolovino smo utekočinjali v reagentu dietilen glikolu (DEG) pri masnem razmerju med lesom in reagentom v razmerju 1:5. Kot katalizator reakcije (95 min, 150 °C - 180 °C) smo dodali 3 % H2SO4 glede na maso DEG. Produkt, iz katerega smo odstranili večino nezreagiranega DEG, smo razredčili z destilirano vodo v razmerju 1:3. Primerno formulacijo premaza smo določili s preizkušanjem kombinacij med vodno disperzijo UL, izocianatnim utrjevalcem (IZ) YCM402 in katalizatorji, ki se uporabljajo v klasičnih poliuretanskih (PU) premaznih sredstvih. Kombinacijo premaznega sredstva, ki je našim kriterijem najbolje ustrezala, smo na leseno površino nanesli s tehniko zračnega brizganja in lastnosti površinskega sistema nato primerjali z lastnostmi komercialno dostopnega PU sredstva na vodni osnovi. Analiza FT-IR je potrdila nastanek uretanske strukture in vodikovih vezi pri utrjenih sistemih iz vodne disperzije UL. Površinskim sistemom smo med utrjevanjem merili trdoto površine po metodi z dušenim nihanjem (SIST ISO 1522), po 21 dneh utrjevanja pa določili še prožnost po Petersu (DIN 53 155:1971), oprijemnost po metodi z odtrgovanjem pečatov (SIST EN ISO 4624), sijaj (SIST EN ISO 2813) in barvo (CIE-L*a*b* sistem vrednotenja barv). Ugotovili smo, da so bile odpornostne lastnosti izbranega sistema UL:IZ (1:1) primerljive s komercialnim premazom YOM750 pri izpostavitvi nekaterim hladnim tekočinam (SIST EN 12720) in suhi toploti (SIST EN 12722). Premazni sistem je bil sicer slabše odporen proti vodi ter delovanju mokre toplote (SIST EN 12721), vendar je izkazoval precej boljšo odpornost proti acetonu in razenju površine (SIST EN ISO 1518).

• Language: Slovenian
• Keywords: utekočinjen les, poliuretanski premazi, FT-IR, odpornostne lastnosti
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [D. Bradeško]
• Year: 2012
• Number of pages: X, 64 f.
• PID: 20.500.12556/RUL-699
• UDC: 630*829.1
• COBISS.SI-ID: 2073481
• Publication date in RUL: 11.07.2014

Secondary language

• Language: English
• Title: Polyurethane wood coatings from liquefied wood : graduation thesis - university studies

Abstract

In the modern world the need for products, made from renewable resources, is growing. Liquefied wood (LW) is a rather new, renewable raw material, which could also be used in the production of polyurethane coatings. Poplar wood was liquefied in a solvolytic reagent diethylene glycol (DEG) in the mass ratio of 1:5, between wood and the reagent, respectively. To catalyse the reaction (95 min, 150 °C - 180 °C) a 3 % of H2SO4 was added, based on the amount of DEG. The product, from which we have removed the major part of the unreacted DEG, was then diluted with distilled water in the 1:3 ratio. The most adequate formulation was determined by testing various combinations of the LW-water dispersion, isocyanate hardener YCM402 and various types of catalysts, commonly used in classical PU coatings. The combination, which best suited our criteria, was then applied on the wooden surface by the air-spraying technique, and the properties of the novel coating system were compared to the properties of a commercially available water-borne 2- component PU coating. FT-IR analysis confirmed the formation of urethane structure and hydrogen bonds in the cured LW-water dispersion systems. During curing, the pendulum dumping test (SIST ISO 1522) has been performed, and after 21 days of curing the chip test for coatings, according to Peters (DIN 53 155:1971), and the pull-off test for adhesion (SIST EN ISO 4624) were performed. Gloss (SIST EN ISO 2813) and colour (calculation of colour differences by CIE-L*a*b*) were also investigated. It was stated that the resistance of the chosen system UL-IZ (1:1) is comparable to that of the commercially available coating YOM750 in the case of exposition to some cold liquids (SIST EN 12720) and dry heat (SIST EN 12722). It showed worse resistance towards water and wet heat (SIST EN 12721). However, the coating system obtained considerably better resistance when exposed to acetone, and scratching (SIST EN ISO 1518).

• Keywords: liquefied wood, polyurethane coating, FT-IR, resistance properties