Uf Pt Board Yemane

8/4/2019 Uf Pt Board Yemane

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Jour na l of Tropical Forest Science 1(1) : 26 - 34.

UREA-FORMALDEHYDE P ART I CL E B O ARD F R O M Y E M A N E(GMELINA ARBOREA)L.T. Chew, C.L. OngForest Research InstituteMalaysia, Kepong, 52109Kuala Lumpur , Malays ia.&Suhaimi MuhammadMara Institute of Technology, Shah Alam,Selangor Darul Ehsan, Malaysia.Received April 1988, accepted July 1988.

C H E W , L.T., O N G , C.L.& S U H A IM I M U H A M M A D . 1988. Urea-formaldehyde particle-board from yemane (Gmelina arborea). Y e m a n e , one of the species of the CompensatoryForest Plantat ion Programme, provides a source of suitable ra w mater ial for themanufac tu re of m edium densi ty urea-form aldehy de par t icleboards. This study indicatesthat yemane can be successfully blended with flakes of other species to produce urea-formaldehyde par t icleboards to meet th e requ i rements of Type 1 Standard Board. T hegood strength proper t ies of urea-fo rm aldeh yd e par t icleboa rds comprising the f lakes ofyemane , ba ta i (Albiziafalcataria) and Acacia mangium indicate that these species arepotent i a l raw mater ia l fo r ure a - fo rma l de hyde p a r ti c l eb o a r d m a n u f a c t u r e .K ey w o r d s : Y e m a n e u r e a - f o r m a l d e h y d e par t i c leboard .

IntroductionYemane (Gmelina arborea), a f a s t growing tropical plantation tree species, has been

selected as one of the species for the industrial tree plantation programme in Malaysia.It holds great promise as a potential source of timber for pulp and other purposes(Wong & Khoo 1980). The timber has excellent working properties. Although ithas been tried for furniture, panelling and matches manufacture, no work has apparent-ly been reported to date on its use for urea-formaldehyde particleboard (U-F board)manufacture. In this paper, we examine the potential of yemane as a source of rawmaterial in the manufactureof medium density U-F board.

Mater i a l s and methodsRaw material

Samples f r o m two 12-year old yemane trees were collected from the plantations in

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K e p o n g . T h e r a w mater i a l used f o r b o a r d m a k i n g t rials w a s f r om those sections of thelogs t h a t were not used for peeling tr ials. M o s t of the samples were in the form o fbil lets of short l eng ths , c. 30 cm. Dens i ty measurements on the wood samples w e r ec a r r i ed out.T h e bil lets were in i t ia l ly cu t into 3 c m t hi ck discs an d fu r ther processed into chipso f a p p r o x i m a t e l y 30 x 20 x 66 cm. These chips were then fed in to a knife-ring f laker ,w i t h k n i v e s set to produce 0 .6 m m t h i c k f l akes . A s the f l akes obtained f rom th e kn i fe -r ing f l aker w e r e f o u n d t o b e o f s u i ta b l e d i m e n s i o n s f o r b o a r d - m a k i n g , n o f u r t h e rprocess ing by the d is in teg ra to r w a s necessary . T h e f lakes were dried to less t h a n 5%m o i s t u r e c o n t e n t b e f o r e sieving to sepa ra te the f ines f rom th e f lakes. Sieve ana lysisa n d b u l k densi t ies of the f l akes w e r e m a d e .

Board-makingSingle- layer U F - b o a r d s

Measured quant i t ies of f lakes and f ines sufficient for the produc t i on of 19 m m th ickU F - b o a r d s o f v a r y i n g densi t ies were sprayed in a Dra i s m i x e r w i t h a resin m ixconta in ing u rea f o r m a l d e h y d e (UF ) , h a r d e n e r a n d w a t e r . The sprayed par t ic les andf ines w i t h a c o n t r o l l e d moisture content of 12% w e r e laid in a wooden mould a n dpre-pressed at 3.5 kg/cm . The conso l ida ted mat was f ina l ly pressed b e t w e e n tw ostainless steel caul plates in an electrically heated hydraulic press maintained at 160Cfo r 8 min. Different sets of single-layer homogeneous UF-boards compr is ing yemanef lakes a nd a n e q u a l a m o u n t o f sepa ra te ly oi l pa lm (Elaeis guineensis), k e r u i n g(Dipterocarpus spp.), industrial wood wastes an d rubberwood (Hevea brasil iensis) w e r ep r o d u c e d . In a d d i t i o n , a set of homogeneous UF-boards compr is ing equa l a m o u n t s o ff lakes o f y e m a n e , m a n g i u m an d batai (A. falcataria) w as produces.

Thre e- l a yer U F-boa rdsFor three-layer UF-boards , th e surface layers consisted of yem a ne f lakes w h i c ha c c oun ted fo r 50% by weight of the m ateria l used fo r m a k i n g each piece of U F- b o ar d .Different sets of UF-boards w e r e made with the core layer comprising flakes f rom

one of the fo l lowing : o il p a l m , keruing , indus t r i a l wood was tes and rubberwood.T h e conditions o f m a n u f a c t u r e for the th ree - l a ye r UF-boards w e r e t he same as that fo rth e single-layer U F -boa rds . Al l the UF-boards were cu t in to test pieces and c ond i t i onedin a c o n s t a n t t e m p e r a t u r e a n d h u m i d i t y room (20C a n d 6 5 % rela t ive h u m i d i t y ) .Strength and dimensional stabi l i ty tests were carried out according to B.S. 5669 : 1979"Specif icat ion o f w ood-c h i pboa rd an d m e t h o d s o f test fo r pa r t i c l eboa rds "(Anonymous 1979).

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Results and discussionT he par t ic le classif icat ion of the f lakes is as follows:Sieve size ( m m ) 0.25 >0.5 >1.0 >1.4 >2.0 >2.8 >3.4 >5.6W e i g h t (%) 2.2 2.8 8.5 9.9 12.3 12.9 7.2 22 .8 21 .4

T h e a v e r a g e b u l k dens i ty o f t h e y e m a n e f l a kes w a s 69.2 g /l at 5% m o i s t u r e c o n t e n twhi le th e average densi ty of the green w o o d o f y e m a n e w as 430.0 g/l .

Single-layer UF-boardsSingle- layer U F -boa rds of densi t ies 481, 561 and 641 kg/m 3 were p r o d u c e d . U F-boa rds of densities a r o u n d 700 kg/m3 gave blowing p rob lems. This was also observedin th e s t u d y of s imilar low density t ropica l hardwood spec ies f rom Pa p u a N ew Gu i n e a

( Iwa sh i ta 1980). M o s l e m i ( 1 9 7 4 ) a t t r i b u t e d t h e b l o w i n g p r o b le m s to the i n t e r a c t i o nb e t w e e n mat m o i s t u r e content and board and the particle dens i t ies d u r i n g hot pressing .The quant i t y o f pa r t i c les in a cer t a in vo lume of pa r t i c le ma t would increase wi th adecrease in the spe c i f i c dens i ty o f the r aw m a t e r i a l r e s u l t i n g in smal l e r o p e n i n g s for thesteam f low with in th e pa r t i c le m at d u r i n g h o t press ing. C o n s e q u e n t ly , a b u i l d - u p o fsteam pressure occurs with in th e b o a r d a n d l eads to b l o w i n g a s steam is not suf f i c i en t l yvented f rom t h e boa rd . H e n c e i t was not possible to produce UF-boards o f densi ty700 kg/rn3 a n d a b o v e f r o m w o o d spec ies w i t h dens i t i es l ower t h a n 0.5 g/ml. A s a fewUF-boards o f density 700 kg/m 3 p r o d u c e d from y e m a n e showed s imilar b lo w in gp r o b l e m s , n o U F - b o a r d s o f s u c h dens i ty were ava i l ab le f o r e v a l u a t i o n . P r e v io u s s tud iesof par t i c leboa rds f rom ba ta i ( W o n g & O ng , u n p u b l i sh e d ) a n d m a n g iu m ( C h e w &J a a f f a r 1 9 8 6 ) s h o w e d t h a t the ir average w o o d dens i t ies a re 0.24 an d 0.41 g/ml ,r e s p e c t i v e l y . In the a b o v e studies, there were a lso b l o w i n g p r o b l e m s d u r i n g par t i c l e -b o a r d m a k i n g .

Table 1 gives some of the strength and d i m e n s i o n a l stability properties of s i n g l el aye r UF-boards m a n u f a c t u r e d from th e y e m a n e f lakes , whi le Tab le 2 gives similarp r o p e r t i e s o f both th e l oca l a n d c o m m e r c i a l particleboards a s we l l a s t h e m e a n q u a l i t ylevels of the d i f fe ren t t y p e s o f b o a r d s s t ipu la ted in Brit ish S t a n d a r d s B.S. 5669 : 1979( A n o n y m o u s 1 9 7 9 ) .

A ll the expe r imen ta l U F - b o a r d s with densit ies above 550 kg/m3 and resin c o n t e n t sin th e r ange of 6 to 12% m et the b e n d in g strength ( M O R ) r e q u i r e m e n t of T y p e Iboa rds as specified in the Bri t ish Standards B.S, 5669 : 1979 (Table 2). For theIn te rna l B o n d ( IB) r e q u i r e m e n t , a m i n i m u m resin c o n t e n t of 8% and density of640 kg/m3 fo r U F - b o a r d s a re nec essa ry ; w i t h a higher res in c o n t e n t o f 10%, l o w e rd e n s i t y U F - b o a r d s o f sl ightly less t h a n 6 00 kg/m3 c o u l d sat is fy the IB of the Brit ishS t a n d a r d s . Increased resin c o n t e n t a n d board dens i ty c o n s i d e r a b l y improved a l l t he

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Table 1 . St rength and dimensional s tabi l i ty proper t ies of single l aye r UF boar ds f r o m y e m a n e

(Press temperatu re : 160 C ; Pressing time : 8 min)

Sample

ABCDEFGHJKLM

Resi nC o n t e n t s

66

.6888

101010121212

Densi ty(kg/m3)

49 75596 4249 856 763 950 958 965 450 259 064 6

BendingStrength( M P a )

13.918.318.613.318.722.913.317.924.712.523.127.0

In te rnalB o n d(MPa)

0.150.190.170.120.220.490.320.660.750.500.710.77

ScrewW i t h d r a w a l(N )

31 841 646 337 947 651 649 760 76 9 154 963 5681

W a t e rA b s o r p t i o n

22.022.610.414.610.7

6. 316.513.5

7.420.78.15.0

ThicknessSwelling

11.110.1

7. 25. 83. 72. 57. 34. 43.47.43.72. 8


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Table 2 . Strength and d ime ns iona l s tabi l i ty proper t ies o f comme r c i a l pa r t i c l e boar ds an ddifferent t y p e s of pa r t i c leboa rds st ipulated in B.S. 5669 : 1979

Density

M a l a y s i a n c o m m e r c i a l pa r t i c l eboa rd ( a ) 714B r i t i sh c o m m e r c i a l p a r t ic l e b o a r d (b) 610 - 640B.S. 5669 - 1979 (c) T y p e I* NAT y p e I I * N AT y p e I I I * N A

(a ) - S t a n d a r d and Indus t r i a l Research Institute of Malaysia(b ) - A n o n y m o u s , 1969(c ) - Br i t ish Standard Ins t i tu t ion , 1979.

BendingSt rength(MPa)26.914.013.817.019.0

(1979)

I n t e r n a lB o n d( M P a )

0.660.350.340.500.50

Screw W a t e rW i t h d r a w a l A b s o r p t i o n

(N ) (%)

5 43 NA360 9.0360 NAN A N AN A N A

ThicknessSwelling

6. 9N A1210

8

T y p e I* S tandardType I I* Floor ingType I I I * I m p r o v e d M o i s tu r e Resistance

N A - NotAvailable


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t h i c k n e s s swel l ings a n d screw w i t h d r a w a l va lue s . All the U F - b o a r d s sat isf ied th e screww i t h d r a w a l r e q u i r e m e n t s a nd ha d t h ickness swel l ing values well below the s t ipu la tedm a x i m u m r a t e of 12% i n the B r i ti s h S t a nd a r d s , w i t h th e e x c e p t i o n of Sa mpl e A ( b o a r ddens i ty 497 kg/m 3 and 6% resin c o n t e n t , T a b le 1). T h u s , to sat isfy a ll r e q u i r e m e n t s o fT y p e I S t a n d a r d B o a r d , U F - b o a r d s m u s t ha ve a m i n i m u m dens i ty of 640 kg/m 3and 8% resin c o n t e n t .

Table 3 gives the s t r eng th and d imens iona l s t ab i l i t y prope r t i e s o f single- layer U F-boards m a n u f a c t u r e d f rom equal amounts o f y e m a n e f l akes a n d separately f lakesf rom keru ing , r u b b e r w o o d , oi l pa lm and indus t r i a l w o o d as well as f rom a n a d m i x t u r e ,c o m p r i s i n g e q u a l a m o u n t s o f f lakes o f y e m a n e , m a n g i u m a nd ba ta i . All thee x p e r i m e n t a l b o a r d s compr is ing flakes o f y e m a n e a n d o t h e r species met the requ i re -m e n t s o f T y p e I boards a s speci f ied in the Br i t i sh S tanda rds . U F - b o a r d s compr i s inge q u a l a m o u n t s of y em a ne , ba ta i a nd m a ng iu m (Sa m ple S) show ed the h ighes t s t reng thva lues .

Three-layer UF-boardsTable 4 gives th e properties of three layer UF-boards comprising flakes o f y e m a n efo r the sur face l ayers and f lakes o f other species for the core layer .A ll th e e x p e r i m e n t a l three l ayer U F - b o a r d s satisfied the r e q u i r e m e n t s of T y p e Ib o a r d , a s speci f ied in the Bri t ish S t a n d a r d s . It is d i f f i c u l t , h o w e v e r , to s p ec i fy w h i c hs a m p l e ha d the best propert ies because n o sa mple disp layed m a x i m u m o r m i n i m u m

v a l u es i n a l l t he d i m ens i ona l s tabi l i ty a n d s t r e n g t h p r o p e r t i e s . S a m p l e U ( c o m p r i s i n gi n d u s t r i a l wood was tes ) , fo r ex ample , gave th e best i n t e r n a l bond, w a t e r absorptionand th ickness swell ing values b u t lost out to s a m p l e W (compr is ing o i l palm f lakes) inb e n d i n g s t r e n g t h a n d screw w i t h d r a w a l . O n t h e other h a n d , S a m p l e V ( c o m p r i s i n grubberwood f l akes) showed the w e a k e s t i n t e r n a l bond, screw w i t h d r a w a l and watera b s o r p t i o n p r o p e r t i e s b u t w a s super io r to S a m p l e T (c ompr i s ing ke ru ing f l akes) int h e b e n d i n g s t r e n g t h a n d t h i c k n e s s swe l l ing v a l u es .

ConclusionsY e m a n e w a s f o u n d t o be a su i t ab le wood species for the m a n u f a c t u r e o f m e d i u mdens i ty UF-boards because single l a ye r U F - b o a r d s w i t h a t least 8% resin c o n t e n t a n d

dens i ty 640 kg/m3 met the r e q u i r e m e n t s o f T y p e I b o a r d , S t a n d a r d B o a r d , a s speci f iedin th e British Standards , 5669 : 1979. Y e m a n e could successfully be blended withf l a k es o f o t h e r denser woods, f o r e x a m p l e , ke ru ing (ave rage dens i ty 0.80 g/ml) a n dr u b b e r w o o d (average density 0.64 g/ml), to p r o d u c e s t a n d a r d m e d i u m densi ty U F-b o a r d s , e i t h e r a s h o m o g e n e o u s single l a ye r U F - b o a r d s o r t h r e e l a ye r U F - b o a r d s .

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Table 3 . St ren g t h and d ime ns iona l stab i l i ty proper t ies of U F - b o a r d s of yemane and other species

( Press tempera tu re : 160C; Pressing time : 8 min; Resi n c o n t e n t :

Sample

NPQR

s

Y e m a n e &Y e m a n e &Y e m a n e &Y e m a n e &Y e m a n e &

Species

k e r u i n gindust r ia l w o o d f lakesr u b b e r w o o doil palmbata i & m a n g i u m

Densi ty(kg/m 3)

6 5 36 6 764 16 7 265 7

Bendi ngSt rength(MPa)

1921 .2221 .

.2

.1

.2

.928.7

I n t e r n a lB o n d( M P a )

0,0.0.0.0.

.4 0

.43

.36

.5 1

.7 1


66 354 956 069 811 1

WaterA b s o r p t i o n

118

221312

.4

.0

.3

.6

.3

ThicknessSwelling(% )

5. 43. 16;36.06.6


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Table 4 . St ren g t h and d ime ns iona l stability pr ope r t i e s o f t h r e e l aye r U F - b o a r d s compris ing f lakes ofy e m a n e for the surface layers and flakes of d i f fe re n t species for the core layer

(P ress t em pera ture : 160 C; Pressing t i m e : 8 m m ; Resi n c o n t e n t : 8 % )

Sample

TUVW

C o r e layer

KeruingIndus t r ia l wood was tesR u b b e r w o o dOil palm

Densi ty(kg/m3)

6 4966 7638648

BendingStrength( MPa )

18.322.520.623.6

In te rnalBond( M P a )

"0.500.550.410.52


68 56 6 265 974 1

WaterAbsorp t ion(%)

16.87.1

39.829.0

ThicknessSwelling

(%)

8. 23.56. 79. 2


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ReferencesA N O N Y M O U S . 1969. B S 1811 : Part 2. Methods of test fo r w o o d chipboard and other part icleboard. BritishStandard Institution, L o n d o n .A N O N Y M O U S . 1979. B S 5669 : 1979. Specification fo r wood ch ipboard and methods o f test fo r particleboard.British S tandard Institution, L o n d o n .C H E W , L.T. & J A A F F A R A H M A D . 1968. "Partic leboards f rom Acacia mangium". Proceedings of the NinthMalaysian Forestry Confe rence,Kuch ing , Sa rawak , 13-20 October , 1986.I W A S H I T A , M . 1980. Mixed t ropical hardwood species f rom Papua N ew Guinea for raw materials of part icleboard.Paper presented at IUFRO Divis ion V Conference, Oxford , U ni ted Kingdom.M O S L E M I , A . A . 1974.Particleboard. Southern Illinois University Press, U.S.A.W O N G , W.C. & K h o o , K . C . 1980. Gmelina arborea - A l i terature review, Forest Research Institute Report No. 14.

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