STUDY UPON THE GLUING SHEARING STRENGTH OF SOME ADHESIVE COMPOSITIONS BASED ON A MIXED UREIC AND FURANIC RESIN

Anca-Maria VARODI
Drd.ing. - Universitatea "Transilvania" din Brasov - Facultatea de Industria Lemnului
Adresa: B-dul Eroilor nr. 29, 500036 Brasov, Romania
E-mail:anknel@yahoo.com

Valeriu PETROVICI
Prof.dr.ing. - Universitatea "Transilvania" din Brasov - Facultatea de Industria Lemnului
Adresa: B-dul Eroilor nr. 29, 500036 Brasov, Romania
Tel: +40 268 412921/int. 166. Fax: +40 268 415315. E-mail:petrovic@unitbv.ro

Abstract: The paper presents the results of some own studies performed at laboratory scale, regarding the gluing shearing strength of some adhesive compositions based on mixed furan resin with furfurylic alcohol of FC-2 URELIT type in equal weight proportions with ureic resin of R URELIT type, which are stipulated to be used for solid wood gluing at environmental temperature.
As catalyst a constant addition of 5% ammonium chloride and IR hardener was used, both in solid state and aqueous solution with the concentration of about 20%, and respectively, 25%.
The gluing shearing strength in dry state and after 24h of water immersion were determined after 4h pressing time at the temperature of 20ºC, whilst using the specific pressure of 0.5 N/mm2 and 0.8 N/mm2.
The specific adhesive consumptions achieved were by 32%-46% lower than the ones for adhesive compositions based only on classical urea resin of R URELIT type, which was used as control sample, while the catalyst type and form were varied.
Compared to the same reference adhesive composition, the gluing shearing strength of the adhesive compositions based on mixed furan resin with furfurylic alcohol of FC-2 URELIT type, calculated in absolute values at the same specific consumption of dry adhesive, was by 43-88% higher in dry state and by 51-164% higher after 24h of water immersion at 20ºC.
The obtained results revealed that, in the case of adhesive compositions that contain mixed furan resin with furfurylic alcohol of FC-2 URELIT type, the pressure of 0.5 N/mm2 leads to higher gluing shearing strengths in dry state, while the pressure of 0.8 N/mm2 leads to higher gluing shearing strengths after 24 hours of water immersion at the temperature of 20ºC. In the same context, using solid catalysts leads to higher gluing shearing strengths than the use of catalysts in aqueous solution, ammonium chloride having a more favorable catalytic effect than the IR hardener.

Key words: furan resin, furfurylic alcohol, adhesive, cold cure, catalyst, gluing shearing strength.

REFERENCES
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VARODI, A.M.; PETROVICI, V.; SALCA, E.A. (2007b). Research Studies Concerning the Jellification and the Gluing Shearing Strength of the Mixed Furan Resin with Furfurylic Alcohol of FC-2 URELIT Type in Mixture with the Urea Resin of R URELIT Type. In: Proceedings of International Conference "Wood Science and Engineering in the Third Millenium", 20-22 June, 2007, Transilvania University of Brasov, Romania, pp.203-213.
*** STAS 12593/1-87. Rasina furanica cu intarire la cald pentru abrazivi (Hot Cure Furan Resin for Abrasives).
*** SR 6643-81 Rasina ureo-formaldehidica si intaritori (Urea-Formaldehyde Resins and Hardeners).