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1 Title <Nte>Prperties f Particlebard f : Albizia falcata Backer Authr(s) SUBIYANTO, Bambang; KAWAI, Shuichi; TAKINO, Shinjir Citatin Wd research : bulletin f the W University (1986), 73: 5-57 Issue Date URL Right Type Departmental Bulletin Paper Textversin publisher Kyt University

2 Nte Prperties f Particlebard frm Lesser-used Species I. Albizia falcata Backer* Bambang SUBIYANTO**, Shuichi KAWAI**, Hikaru SASAKI** and Shinjir TAKINO** (Received September 1, 1986) Abstract--Flakebards in the density range f gjcm 3 were prduced using Albizia falcala as raw material and a urea frmaldehyde resin, a phenl-melamine frmaldehyde resin, and an iscyanate cmpund as adhesives. Mechanical prperties and dimensinal stability f bards were determined. Using lng flakes frm this' lw-density species, high MOE and MOR was btained in relatively lw-density bard. Further imprvements in internal bnd strength and the dimensinal stability in thickness directin may enable t prduce bards sufficient fr stuctural use. Iscyanate bnded bard shwed superir prperties t thse bnded with ther ad-, hesives. 1. Intrductin Utilizatin f lesser-used trpical hardwd species, fr particlebard is cnsidered t be ne f prmissing means f expanding the raw material base fr the wd industry. Technically, it is pssible t make particlebards frm many species f wd in almst any frm, regardless f bard qualities. Hwever, nly limited number f species are being used, and infrmatin n many unused species f hard-. wd is lacking!,2) Albizia falcata and ther fast grwing tree species, fr instance,. still haven't fund any majr use as structural building materials. In this paper the suitability f Albizia falcata, ne f unused species in Indnesia, as a raw material fr particlebard bnded with urea frmaldehyde, phenl-melamine frmalde-' hyde, and iscyanate adhesive resin will be discussed. 2. Experimental Raw material used was Mluccan sau (Albizia falcata Backer) with an air-dry density f.34 g/cm 3 Fingerings were' prepared using a circular saw with nminal size 5 (fiber directin) X 25 X 2 mm,and they were prepared t flake-type par- * This paper was presented at the 35th Annual Meeting f the Japan Research Wd Sciety at Tky, April, ** Research Sectin f Cmpsite Wd. -5 -

3 SUBIYANTO et at.: Prperties f Atbizia Fatcata Flake Bard ticles with a Pallmann knife-ring flaker. The average dimensins f the particles were 3 mm in length, 2. mm in width and.48 mm in thickness. A part f the particles were dried with a vacuum dryer until abut 5 percent misture cntent and the rest were cnditined t 1 percent misture cntent. In additin t a cnventinal urea frmaldehyde resin (UF), U-Lid 555 frmulated by Mitsui Tatsu Kagaku C. Ltd., new types f resin fr particlebard were used; an iscyanate cmpund adhesive (IC), UL-48 frmulated by Gunei Kagaku Kgy C. Ltd., and a phenl-melamine frmaldehyde resin (PMF), U-Lid NV 11 frmulated by Mitsui Tatsu Kagaku C. Ltd. Resin cntent level f bards fr all types glue was 8 percent resin slids based n ven-dry weight f particles. In the iscyanate adhesive frmulatin, acetne was added at 2 percent based n weight f resin slid, while water was added t phenl-melamine frmaldehyde and urea frmaldehyde adhesives t attain 5 percent resin cncentratin, and get a suitable viscsity fr spraying. The resin was sprayed n the particles in a drum-type rtary blender by means f an airless gun. Particles with 5 percent misture cntent were used fr PMF and UF resins, while thse with 1 percent misture cntent fr IC, which were established t be the ptimum misture cntent fr bnding strength in each resin in the previus experiment 3 ). Handfrmed particle mats were pressed at 16 C fr iscyanate resin and 13 C fr phenl-melamine frmaldehyde and urea frmaldehyde resins. Fr IC resin, bth tp and bttm surfaces f the mat was cvered with glass-fiber reinfrced Tefln sheets s as t prevent the mat frm sticking t the platens. Target bard densities were.4,.5 and.65 g/cm 3 in air-dry cnditin. The initial pressures f 15, 2, and 25 kg/cm 2 were applied fr 3 secnds fr the bards with densities f.4,.5,.65 g/cm 3 ), respectively. The ttal pressing time was 7 minute fr UF and PMF resins, and 3.5 minute fr IC resin, applying a step-dwn methd f pressing. Specimens cut ut f bards with the dimensins f 4 X 35 X 12 mm were tested after cnditining fr 2 weeks at 2 C and 65% RH. Mdulus f elasticity (MOE) and mdulus f rupture (MOR) bth in air-dry and wet cnditins, internal bnd strength (IB) and screw-withdrawal resistance (SW) in air-dry cnditin, and thickness swelling (TS) after 24-hurs water immersin were measured accrding t JIS A-598. In additin, linear expansin (LE) was measured with the wetbending test specimens. The wet treatment fr bending test was tw hurs biling, then ne hur water immersin at rm temperature fr PMF and IC bnded bards, and tw hurs immersin at 7 C, then ne hur water immersin at rm temperature fr UF bnded bard. Six replicatins were used fr each cnditin

4 WOOD RESEARCH N. 73 (1986) 3. Results and Discussin The relatinships between MOE, MOR in air-dry cnditin and the bard density'are shwn in Fig. I and Fig. 2, respectively. Bth MOE and MOR f bards bnded with each type f resin increased linearly with an increase f bard density. IC and PMF bnded bards shwed higher MOE than UF bard at the 'same bard density with the IC bards shwing the highest MOR values. Type 2 Fig & Air-dry bard denstiy (g/cm 3 ) Mdulus f elasticity in dry cnditin as a functin f bard density. Legend: IC; Iscyanate bnded bard, PMF; Phenlmelamine frmaldehyde bnded bard, UF; Urea frmaldehyde bnded bard..7 Fig. 2. O a.--, Air-dry bard density (g/cm 3 ) Mdulus f rupture in dry cnditin as a functin f bard density. Nte: Legend is the same as in Fig

5 SUBIYANTO el al.: Prperties f Albizia Falcala Flake Bard particlebard graded by JIS can be btained with Ie, PMF and UF bnded bards at an air-dry density f.45,.5, and.55 gjcm 3 ), respectively. Similar bservatin were reprted in a previus paper 3 ), but the values btained in this experiment were smewhat lwer than thse in the previus experiment at the same bard density level. This is perhaps due t different methds f particle preparatin. Visual bservatin indicated that the ring-flaker used in this experiment prduced mre... '-"' c ':>-. 4 ' IC 3 PMF 2 '" til... '" =' '"3 1 '"C Fig. 3, O'---...L I l Ari-dry bard density (gjcm3) Mdulus f elasticity in wet cnditin as a functin f bard density. Nte: Legend is the same as in Fig. 1. r u bi5.!o: '-../ 'IC PMF Q.) : ='.. :... ='... 1 "3 '"C Fig & a Air-dry bard density (gjcm 3 ) Mdulus f rupture in wet cnditin as a functin f bard density. Nte: Legend is the same as in Fig

6 WOOD RESEARCH N. 73 (1986) damage t particles than drum-baker used in the previus experiment. Figures 3 and 4 shw the relatins f MOE and MOR in wet cnditin t the bard density, respectively. the dry MOE and MOR, respectively. The wet MOE and MOR shwed trends similar t the treatment in the UF bnded bard f higher density. These values were subsequently excluded frm the regressin equatin. Hwever, delaminatin was bserved after The retentins f the MOR f IC, PMF and UF bnded bard were 53%, 58%, and 47/' respectively. The IB f particlebard is a measure f. bnding efficiency. Internal bnd 5 Ie t::.. PMF Fig. 5. """"-_L-....& Air,.dry bard density (g/cm3) Internal bnd strength in relatin t the bard density. Nte: Legend is the same as in Fig. 1. f IC and PMF bnded bard increased with increasing bard density, as shwn in Fig. 5. On the ther hand, IB f UF bnded bard decreased with increasing bard density. This peculiar trend may be due t the lcal delaminatin f UF bards f higher density; The bnding strength f UF resin culd nt exceed the internal stress f bard due t excess misture which culd nt escape frm the mat because f the high cmpactin rati with thin Bakes. This can be bserved in the springback phenmenn after cnditining, as shwn in Fig. 6. Thickness f UF bnded particlebards increased after cnditining. The internal bnd strength f IC and PMF bnded bards is nly ne-half f that f lauan bard' f the same density3). This can be partly explained by the difference in methd f particle preparatin, as previusly discussed. The lw density f raw material als made it mre difficult t btain higher quality particles. The bnd-ability f the wd species may be anther reasn. Further experiments t imprve bard IB f bard with special cnsideratin in particles preparatin is necessary

7 SUBIYANTO el ai.: Prperties f Aibizia Palcala Flake Bard '" 6"2 '-" 15 1 u (1$..c 5.Ṣ b/).... rj) :U F 6. : PMF D :IC Fig Air-dry bard density (g/cm 3 ) Springback f particlebard after cnditining abut 2 weeks. Nte: "Springback" is defined here as the rati f bard thickness after cnditining t the target thickness. Springback (%) =D 1 -!22 X 1 D where; D: target thickness, D 1 : Legend is the same as in Fig. 1. thickness after cnditining.. '-" 8 O_.l--_-_...I-_ """" Fig. 7. Ari-dry bard density (g/cm 3 ) Srew-withdrawal resistance as a functin f bard density. Nse: Legend)(the same as in Fig. 1. The relatinships between srew-withdrawal resistance and bard density is shwn in Fig. 7. SW increased linearly with an increase f bard density. SW seems t be influenced mainly by the density, althugh Ie bnded bard shwed higher values than the ther bards. Fig. 8 shws the thickness swelling after 24 hurs f water immersin In rela

8 WOOD RESEARCH N. 73 (1986) 5 ""' " '-" bo 3 'ii '" 4) I:: :.E E-< 2 1 Fig. 8..".5.6 Air-dry bard density (g/cm 3 ) Thickness swelling after 24 hurs water immersin in relatin t the bard density. Nte: Legend is the same as in Fig. 1. tin t the bard density. TS increased linearly with increasing bard density, which maybe due t greater thickness recvery after cmpressin in higher density bard. Cmpared with the ther bards, UF bnded bard had the greatest amunt f thickness swelling. Principally, TS wuld decrease with increasing the,resin cntent and with decreasmg cmpactin rati, particle thickness, and particle length 4 ). The quality.4 : UF,6:PMF : Ie.3 '-" I::.9 OJ '" Q) 6. ;, 2.' 6. R 4) l ) I:: & O-----' l...L.-,JI;"I,...I.I-_---JL...L...L-.---Ulu...&.IjLJ...I Air-dry bard density (g/cm 3 )' Fig. 9. Linear expansin in relatin t the bard density. Nte: Legend is the same as in Fig

9 SUBIYANTO et al.: Prperties f Albizia Falcata Flake Bard (i.e. particle surface cnditin, fiber damage) f the particles is may be anther factr. Further experiments searching fr suitable cnditins t decrease the TS is necessary. Fig. 9 shws the relatin f linear expansin t the bard density. The LE f IC-bnded bards shwed the lwest values and decreased with an increase f bard density, as is bserved in ther literature 5 ). PMF bnded bard seems t be independent f bard density. On the ther hand, the LE f The LE f UF bnded bard increased with an increase f bard density, and shwed the highest value in spite f cmparatively milder wet treatment. 4. Cnclusins Mechanical and dimensinal prperties f Albizia falcala flakebard with UF, PMF, and IC adhesives were determined. bnded Using lng flakes frm lw density species, high MOE and MOR was btained in relatively lw density bard, but the internal bnd strength and dimensinal stability in thickness directin f bards were nt sufficient. t decrease TS and imprve IB is necessary. prperties t thse bnded with UF and PMF. Further experiments searching fr suitable cnditins Acknwledgetnent IC bnded bard shwed superir The authrs wish t thank Mr. O. Pulid fr his critical reading, and the members f the Cmpsite Wd Sectin, Wd Research Institute, Kyt University fr their help and suggestins. References I) M. IWASHlTA: Prceedings f Tenth Washingtn State University Internatinal Sympsium n Particlebard, (1976), Pullman. 2) B.R. VITAL, et al.: Frest Prd. J., 24, (1974). 3) V. MALLARI, et al.: Mkuzai Gakkaishi, 32, , (1986). 4) S. KAWAI, et al.: Submitted t Mkuzai Gakkaishi. 5) S. KAWAI, H. SASAKI, M. NAKA]I, S. MAKIYAMA and S. MORITA: Wd Research N. 72, (1986)