CA2067824A1 - Method of modifying treatment of timber and the like - Google Patents

Abstract

2067824 9105643 PCTABScor01 Confident that, when cracks occur in a piece of timber due to the heat treatment of the timber, an acoustic emission (AE) should occur, an effective AE signal directly involved with the cracks is discriminated and detected, and, in addition to this, the total (integrated) number of events and the rate of occurrences of AE
are monitored while the drying treatment process and the high temperature treatment process are discriminated to thereby put all above evidences together to predict cracks occurring during the processes of the drying treatment and the high temperature treatment, whereby the temperature and humidity are controlled on the basis of the predicted information to thereby control the atmosphere such that the cracks will not occur. Furthermore, in that case, the timber is impregnated with a specific organic solvent medium to conduct the impregnating treatment where the water and the heat react chemically with each other, whereby the interior of the piece of timber is plasticized and the cracks due to the heating treatment are prevented from occurring and the brittleness in the quality of timber due to the high temperature treatment is greatly bettered, thus improving the workability of the timber.

Description

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~.:,.i, Method or~jModifying :Treatment of Timber and other ~,', Wood Products . ~

Technical Field ~ i '''"
This inveotion relates~ to~a~method for modiying ~"
tr`~aYm~nt of timber and other wood :products;~ wherein, in 1'.;' applying :heat; treatment ~of ~various vegetabLe worked '~
materials such as log, worked timber or bamboo material, '' etc.' ~hereinafter refe~rred to as "t'imber and other wood ,'~, products~ or '~t~imber ,and the like": depending upon ~: ,;,,' c~ircumstances~:' whi~le makin~: use :of~::charac~eristics 'that ,:~"
the~ timber and t~he ~like'~naturally,~have to~ manu~acture ve~e:table~worked~mater1als~to~whLch:va~ious~characterifitic are~added,~tnls;~method~:~is adapted~ to have the ability to l~r pre:yent~a ~c~ack~ln`t1mber~ and: thé~ l1ke subject to heat '","`,i t~rea~tment,~''a~nd~;'to lmp~rove workab~ility, of ~timber and the , ~ j, like,~ whi~ch,~ ha~s~; a~ tendency~ to be deteriorated bv appl1ca~ioni o heat~ t~hus;to a1:low ;su:ch timber and the ~: : ;,~.
':like;~ to~be` vesit`àble~,worked~ materiaIs having a higher~
quality ~and~ more~ ve:rs:at~ile property' as compared to the:
prlor art.

B a~c k g r o u n d: ~ A r t ~

:He~retofore~ a technoLogies ~ :;to~ :apply : high 206~82~ ~
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. , temperature heat treatment to timber and the like to l.~
change them to worked materiaL having new characteristics ~ :
ha~e been:already announced. ~ As the~t~echnology of this kind, there are a m0thod of applylng heat treatment to ~ .
timer~or~bamboo material, etc. at a high temperature in the atmosphere of a incombustibLe ~as to process or work : , : , : : :
: timber so that it :is in a form:of lignite or~ ossil wood ; (Japane.se :L~id Open Patent ~ppLica.ion~o. 135004/81~, a ~ me:thod of manuacturing a smoked :bumboo (J~panesè Laid : Open AppIication No. 212007/82), a:method o modi:ying treatment of vegetabLe worked material such as timber, bamboo:~aterlal, e~tc~.~ The: inventoxs o this application ~ ~ , . . .
are~develop~Lng to put into~practice a new vegetable work~d , .
ma~terial using t~h~se technolog~ies to appLy h~eat treatment ta~ timber and the;~like~:as~ an:artif~icial lignite or ossil wood,~ an artlfic~lal ~smoked bamDoo:~or a hign temperatu~e at:`tirea:ted~mater1aL.~ Such high temperature heat tre~ted mate~r~ aLs:~so::caLled a :ne~w materiaL are not only utilized a~s~;;substitutes :~o~r~nat~u~al _i~nite:: or~foss~le wood in : .
short:~ supply~, bu~t~ also~are utilized~for comblning pieces having~:light and~sha~ding with each ~other.to make up:a ~ ~.
beautiful wooden~mosaic,ior are util1zed for;furniture or ::.
facing material by making use of adhesiveness or machine : ..
workablllty ~whlch~ cannot be ;en~ounte~red`~with: natural ; ; ,;., 1igni~t~é or~fossile~ material, and the; :propbrty; to :give ::lig:ht : and~:shading in . coLor tone:::by a: temperat~ure .'~

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... ;`, ~ difference. Further, in recent years, by mAking use of : ~ the characteristic that~ such new materials are diffi'cult ~ -,. .~ ., to be rot because they are heat-treated, there new materials are exhibit1ng usefulL~ness or utility in various ields such as water related facing material such as bath ;~
: tub, Lavatory or kitchen uni~, etc.
However, :.there are many instances where high .
: t~mperatu~-e heat tre~tment of the timber and the like is uch~t~hat~ there may take~place a~ heat treatment crack ::: during manufacturing, glving rise to the draw~acks that : ~ .
the yleld is lowered~and/or the workability of p~oducts is ,. .
de;te~rlorated to more ~degree as compared to timber and the like~to which no:heat treatment is implemented. For this ~.
reas~on,~ there took place a technical :requirement to :
: : ::improve this. :~
In~the:co.urse of se:arching for ~a cause of "crack" i~
in .timbe:r: and ~other~ wood:~products ~subject to heat .t~ea~tment~to study~mè~thods of preven~ting this, since crack i;
b.y~drying~or heat``~is~a~sort of:destruct~ion of 50~ id,; the :~ t~
LnventorS have ~ass~umed tha;t ~there~should ;be~any: acoustic emLssion ~(AE). ~On~the bas:is of observatLon of such AE, ;they~ began to~ ma~ke~studies of a te~chnology ~to detect a "crac:k":or predict:":crack" by:drying:or :heat. ~t the same `:::time,:they inves~tig~a~ted technical literatures ln regard to~
the:~relat~ionshlp~be~twee.n~ "crack"~o~timber~and AE. As a result,: they noticed a known technology o "Device for .

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predicting and preventing crack of timber by drying : (Japanese Patent Publication No. 7317/88). ~:
. ~ Further, in~recent years, the inventors have obtained the f.inding that timber can be changed to~ a material having a ~lexibility similar to: that oL: plastic ~.
by a simple chemical reaction.
; The inventors take hints from the abo~e facts to :conduct s~udias with a ~iew to reaLizing prevention of : :
crack and~ improvement in workability oE:material in high temperature heat treatment of timber and other wood ;.~;
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: products having a condition more:rlgorous or sever than t~hat~: of~ the drying treatment,: thus to complete the invention of this appL~ication. i.
It is considered that the cause of a crack ¢i:i~
; occurxlng~in a~ timber, etc~when high temperature heat :
: trèatment:is irnplemented thereto is mainly due to movement ,~.j of~molst~ure in the~heatlng and drylng~process, contraction ~ ll :`of~tlss~ue,~and decomposition of cellulose. ..
Fi~rst o~ alL, ~tbe following flnd~ing was obtained in co;nnection with crack of timber, etc:. ollowed by : .`
, ", movement~of~moisture~in the~heating and drying process and::.~
cantraction of~;tissue. As a moisture ln timber, there are ~.
ordinarily a free~water and a~combined or:absorbed water.
Durlng~: drylng,~ only~ free water is~first dlssipated and .
removed .at~the surface layer.~ According as drying lS
developed, combined water will be aLso remaved. In the 4 - :: : :.
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case the ~former movument of free water, capillary phenomenon is dominant, On~the~ other ~hand, the latter movement of combined water~is based on diffusion. In this way, free water and combined~ water at the surface layer of timber are moved, so timber~is dried, However, the inner layer still remains in ~the state having a high moisture pe~centage. Thus, the~dry portion attempts to contract, whereas ~ Lhe molsture ~cont~ined porti~n resists contraction. As a resuLt, at th0 ormer or ~irst part o drying, tensiIe str~s~ is exerted at the surface la~er and compressi~e stress is exerted at ~the inner layer.
According~as drying~is~urt~her developed, these stresses become~ large,~ and~ contractlon spreads internally.
owe~ver, s~i~nce~the~surace layer is s~bject to a large tensile stress~at all times, permane~nt deformation takes plàce~in~ such~ a manner that~ ~he~ surface layer is not ncrmally~contracted. Thereaf~ter, as the result~of the `act~ that~a¢cording às ~;the inside is dried,~the surface layer~a~t~tempts~to;cause a normaL co~ntraction, positive and negative stresses are~ reversed. ~At the latter part of dry~ing, the surace;layer~is subject~to compressive s~tress and the inner! layer is~subject to ,tensile stress. For thls reason, when the;tenslle stress~is more tha~n tensile str n~th ~o the woody ;part, a wood section~ crack or a urfacu crack along the surface tissue takes place at the former part of drying, and an internal crack takes~ place 2 0 ~ 7~ 2 ~
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.~ ,~. i, at ehe latter~ part~ of~ drylng. In add i t ion, surf ace hardening, andlor~defect called~depression also occur with drying.~ It ha~s be-n ~found that they are all directly~
relat~ed to; the ~magnitude of gradient ~o~ a moisture perae~ntage distribution inside timber or~wood. ~In the he:a~t:~d:ryi~ng~,:; i;t~ i~s~required ~that defects such as various ~
cracks,;~etc~ do~not~take place, and that the gradient of a :.~~' ~ois~t~ure~ per~entage~;d~istribut1on insiae wood~ is as great as~ po s s ib le~ ~ to s hor te n the ~ d rying t ime . To irea l:i z e t h i s~i t i 9 important :to . ~ grasp a moisture pè~centage distribution eve~y hou~ inside timber. Further, lt lS
required~to~ dry~tlmber ~while~ad]usting~e~emperature~ or~
hum~i ~it `~ln~ depe d~ency~upon a mo~isture pe~centage of a timber~;b~ing dried.~ ;However, since~; the~ timber tissue~is ;com~Li ~ ted~ and ~various thermal propert~ie~s~ are afected ~ "
by~ à~ humidity~ mo~lstu~e percentage~ and ~ary~ according to the ` ~kin~ woods~
à~mois~tùr~ pe~cen~ g~ d ~st~ri~bution~:ev ry ~hour ins~ide~ wood.
In`add~ on-,~ s~1n~ce~;mechanical streng~h and~/or thickness of 'a mater~ial also ~ tak'e~ part~ in':~a crack ~ta~king place followed :~
.b;y~: dr~yi~ng,~ in ~ the:~ cas:e of; a~ complicated timber tissue, ~ ,~",, having great anislotropy,i it is extremely dif~icult to make' clear on:~: what~ ;co~nd~itlon~ a' ~d~e~ect :~ takes place~
c:~ord~lngly,, ~t~ s~; :;the: present: ~state that,~ in ~ the;
con~ventiona~l dry~ing tréatment, one ~ enter~s: a room ~ in the course of ~',drying~ t~o conf l:rm a crack ~by~;eye measurement to~

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re-adjust the atmosphere~in the room. However, wLth this : method, it is difficult to predict a :crack be'fore . . .
occurrence thereof, and: it is impossible to find out a crack o~curring lnside. In addition, ~ in a high "~
temperature heat :treatment as in the invention of: this 1 .
appllcation. particu}arly in the case of a condition 5uch that~:lncombustible. gas~ i9 filled,~this me.thod Ls unable to : :i; .
b carried out.
Further,: in:the~case oE the`hLgh temperature heat treatment, when a wood is su~ject to high hemperature, cellulose of ~the wood~begins to be dissolved, so the meahanical~strength of material is weakened. As a result, 't~
w;ood: is~apt to :be~ cracked. Accordingly:, in the case of ;;the hLgh~temperature heat treat.mént, by hLgh~ con~ractLon ~,'5j`' fac;tor~of heat~by~high temperature and weakened mechanLcal strength o:f materlal, there:results~the state where it is ,;.
ext~remé}y difficu~l~t~to prevent~ :crack:~rom a technical:
`poin~t;o~f~view as:~compared ~to the~method of simply drying ?.",'~
wood.~
:Meanwhile~:~, in the method of:~orking or processing timber so that it~:is in the form:of lignLte or Eassil wood~
:Japanese~ Laid~OPen~Patent Application No. 135004/81), the ~
method of manu~Eac~turing a smoked bamboo ~Japanese Laid ; ..
Open:~Patent Applicatlon No. 2:120~07/82~j:,; and the method of~
mo~d:if~ying tre;atmen;t~of vegetab~le ~worked material s~uch as timber: or bamb:o.o material,; which ~ were previously ~ .

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~ developed, any measure relating to a crack subject to heat . .
treatment is hardly considered. For this reason; in'the ~ case where these methods are adopted on~ an industrial : ~ ~: scale basis, it is the most important technical subject to ~;~
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allow products :to be free ~rom crack and have high quality, and to manufacture usabLe producta with good yield. Also from a viewpoint of payabil:ity,j this is an ,.
important subject or tneme.
In view of this, the inventors ~have drawn i.
attention to the known technology (Japanese Patent Publication No. 7317/88) t~ carry~out prediction of a .~i crack~ by ~drying~ of timber ~y using the AE~ detectIon techno~Logy~to control~:the ambient:tcmperature ~and humidity o~f~timber, thus to prevent crack. Howcvcr, in the above ;i ncwn 'iterature, lt is only descri~e~ t.~at~a m2~h~d o I:.
prcdi~t~g:an in~tial~crack iD the dry}ng trQatment o~ the :basis~ o~ the numbcr: of ;accumuLatcd and the rate of oc:currcncc of AE. ;~Namcly, even in the drying treatment, prcdict~ion~of an initial crack of drying LD ~a temperature ;zone of 30 to 80~~C~is on1y conducted,~but coDsidcration is not~ma~de in~conncc;tIon with a crack in thc Lattcr part of the drying trcatment and/or a crack in thc treatment to .~`;
carry out a high~temperature heat~tr:catment above 1000C.
F:urther, thc mcthod of predicting an lnitia~I crack onLy a procedure to know~the number of ~accumuLa~ted AE and: the rate~: of occurrence~ of AE immediately::b~fore~timber is .. ,!,, . . .

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cracked to operate a control equipment when the AE
occurrence rate reaches a~limit value to relax tha dr~ing `condition, thus to prevent a crack. In thi.s invention, the correlation between the number of accumulated AE or the rate of occurrence of ~AE and a~crack is effective for an; initial; crack~ by drying, but the correlatlon is not necessarily~exhibited in the case of th~ Latter part o~
urying or high temp~erature hea~ing.
Furt~her, ~it ~has ~been ~ found ~that ~slnce the `occurrence characteristLc ~of AE var.ies according to ; j individual circumstances of a wood ~timber~ subJect to trea~tment, and that~characteristic varies acco~rdlng to the kind~ o~f~woods (timber),~criteria conforming thereto are required.~ The inventors~notlced that cra~ck;of tlmber has a c;losé cor_~lztion~with~the ~mplitude of an ~E s1gna~ in the~ course~of ~abserving and analy~ing occurrenc~
circumstanaes~of cracks of timber and AE signals, thus to pay~ atten~tion to~ the~amplitude o~ the e}ectric signal to discriminate and detèct~ an effective signa.L directly rela~ted ~to~crack~ Thus, in the~case~even when a single AE~ s1gnal is~detected~ where the amp}~ltude of that AE
signa} is largè~ t:hLs slgnal is consLdered~as a dangerous siignal for crack. ~Further, monitoring of the total number of events (accumu}ated va}ue) and~ the~AE occurrence rate 5 conducted by~on~}ine on the basls~of such AE sLgnaLs~to~
synthetically judge the state of timbex, thus to~predict 20~7824 ~

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in the course of treatment. Then, temperature and i;
humidity are controlled on the basis of this predi~ted information to control the atmosphere so that no crack ,;
takes place in the timber, etc,~ This method is applled to .. , .:
the totaL process o~ the drying treatment process step and the high temperature heat treatment process step to prevent a crack of ~imber during treatment,~thereby making ;possible ~o manuracture, witn good yield, usabLe modiying treated products of~tlmber, etc. Namely, a first object is to;provide a new technology capable of efficiently manufacturing~ high temperature heat treated material~ of a high~quaLity from an industrial point of iew.
Furtber, impregnating t~echno}ogy for timber is w dely a~op~ed. Y.oweve~, the-e is not know~ the example where any impregnan~t is used;in adv2nc2 with a view to~
preventing a~crack~in~ drylng or heat treatm2nt. The inventors have obtained the finding that whe~n a speciic organ ic ~ ~: s olvén t ~s e~le~ ted from various impregnan`ts is impregnated lnto timber, ~etc.~ there2fter to app1y he2t tre~atm2n~t~thtereto,~ chemicaI reaction~tak2s pl~ce inside, so internal plasticization occurs so that thermal fluidity rendered to material. Thus, the ~inventors have considered that when this finding is~applied, thermaL
fluidity Lnside ~tlmber may prevent crack in ~the heat treatment, thus to ` develope the~ invention of this 2 0 6 ~ 8 2 ~

,,.''. ' .!~, application. Namely, by impregnating a speci~ic organic solvent to implement impregnating treatment to cause hydrothermaL chemical reaction,; the inside~of timber is plasticl~ed. Thus, there i5 pr~ovided a second ob~ect to prevent crack by heat treatment, to greately improve 1,""
brittleness o wood property occurring by the high temperature~heat t~ea~ment, thus to~imp~rove workability.v ". ",~:
DiscLosure of the Invention ; ~ ~
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The invention of this application contemplates ;~
attaining, by combining the ollowingltechnical means, the technical~subject to preven~ occurrence of crack during ;`~
` heat t~reatment and to prevent lowering oE~ workability as 1:
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;the r~esult of the ~act~timber becomes bri.ttle by thermal r~at~e~nt, ~h sh ~ar~ drawbacks of the method of modifying tr~3~ment~0f~ timber to~ imp~ment ~high temp~rature heat treatment~ in the at~osphere of incombustible gas already n~ented~as previously descr1bed~
As the~result o the fact that the inventors has conducted ~studies ~on a crack in the case where heat and drying treatment of timber, etc. is impLemen~ed, it wa 5 made clear that such a crack takes place by movement of moisture, contraction of tissue and decomposition of celluLose~by high~temperature.~ It lS~ considered that a crack~in heat ;treatment of timber is~ one~of destrutive forms~; of solid,~so~ acoustic emlsslon (AE) should be -!.. ~' i 2 ~ 6 7 8 2 4 ;.....
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produced similarly to crack by drying. Further, it is ; :,;~
considered that if ~that AE signal is detected ~herëby ii~;
~ . making it possibl~ to know its frequency~ and signal ;`
; ~ strength, these information are processed, thus making it possLble to predict occur Ln advance. As the result of studies, the inventors noticed that crack of timber has a ; close correlation wit;h the ampl~tude together with , ~ , occurrence ra~e of AE signals to pay attention to the amplitude of the electric~ signal to discriminate and detect an effective signal directly connected to cr~ck. i~`~
As a result, in the case where the amplitude is large even when only one A~ signal is detected, this signal can be consldered~ as~a dengerous signal ~or~ crack. Further, monitoring of the ;~AE accumulated event number and tha AE
occ,~rrence rate ls made by on Line on the;basis of ~ne above AE ;signa} to discriminat~s pnases or stages or dryi~ng or~heat treat~ent to analyze and; study the meaning o~ an~AE signal deteGted while making a comparison with a re~f~erence~va~lue empirically dete~rmined~in advance to car~y out predict;ive ~udgment of crack in the course o~f !~
t~reatment to control temperature and humiclity~on ~he basis of predictied information to effect a control to relax the tmospherlc condltion~ so that~no~crack~takes place in t~lmb~er, etc. ~It is~further made clear that~since crack of 1~9."' t~imber, etc.~is caused by movement o~moisture followed by the ~ d~yi~ng treatment and ~the~ heat ~treatment, and ~, ::

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denaturat~on of material due to heat, if temperature and `'~
humidity are adjusted as a control factor, crack'~a~ be I~ , su~ficiently prevented. ; '"' !` .i:
Further, when an approach is employed to ~,~;', impregnate an organic impregnant thereafter to contain it '':' into a~high temperature water~more than lOOC to dissolve ,', it by hydrothermal, reaction ~hydrolysis), the woody part i~
is chemically chan~ged ~into the state havins a thermal !j, ~
plas~t,icity ~thermal ~luidity). Thus, it lS made clear ,, that si~ce the woody part i5: de~ormed`in cor~espondenc2 ,~,' , with a difference between the tensile stress and the comprassive ~stress at~the sur~ace layer and the internal ,'' layer, occurring by~ appLlcation of heat, no crack takes ,~
place, and th,at the~Pact~that the woody part i9 chemically ~ c, changed in~to;the state having thermal plasticity (thermal ''~, fluidily) by~impregna~ion or an organic~imgregnant reiaxes l',', brittleness of the~wood property taking place by the high ,',, temp~erature heat treatment~, thus~ to lmprove workability. ,I,~, These three~ideas are recited as follows. I ,`~
First is ~to ~improve workabilit~y by pre~enting~ ,,, crack by~the impregnat~ing treatment by an organic agent, -'~
and by~allowing timber to be chemically modified timber. "
Second is to; detect an AE signal to predict a crack of timber, etc. by ,the information process1ng '',' thereof to carry~ out~;atmosphere~ control uslng,~ as a '~
control factor, temperature and~humidity on the ~basis of~ ~, 13 ~

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the predictied i~formation" thus to prevent crack.
Thixd is to carry out heat and d~ying treatmënt . and high temperature heat treatment at a normal pressure or a hig~ pressure while conducting control o~ atmosphere to thereby irnprove the wood property characteristic and ~.
~ the functional chara~teristic. ~ 1 ;, ~
By suitably combining these ideas, this invention contemplates~providing a new vegeta~le worksd matarial in which timber, etc.~ is e~ficiently subjected to modi~ying ~reatment so that it has a high guality.
Inventions for which the patent is sought to be aranted wil~l now be~described in deteil.
The first~ invention for which the patent is sought to be granted resides in~ a method o~ first impregnating an organic impregnant, e.~g., oxyether such as polyethylene glycol or methyl~celLosolve, etc., polyatomic alcoho~ phenol, natural rubber,~ synthetlc rubber, or mixturè~including~ them in combina~tion into various vegetable;w~rked ma~terial, et~c.~ such as a Log, a worke~
timber~, ~a~ bamboo stuff ttimber or any other wood product) o allow it hydrothe~rmal chemical reaction ~(h;ydrolysis) to , ; take~place,~thus;to carry out impregnating~treatment~
Materia~L subject to treatment o~f this invention ; is~timber, etc., but ~lncLudes~ a~Ll vegetable worked j~
materi;als such~as log, worked~timber,~ bamboa stuff, etc. ~;~
rrespectlve of the~ kind~of vegetables.

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Further, a specific organic impregnant to be ~ impregnated may employ an oxyether suclh as polyethylene ;~
; . glychol, or methyl cellosolve, et~., polyatomic alcohol such as 1 , 4 butanediol, etc., phenol, a natural rubber, 1:~
synthetic rubber, or mixture including them in combination, : . , ~ ~ Change of the wood property ~occurring by the .
; impregnatin~ tr_a~ment will now be d~sc~Lbed~

Chemically, timber is comprised~of celluLose of ~,; .:
~ ~ 40 to 50%, hemic~llulose of 15 to 25%, lign~in of 20 ~4 .'.: ;.
30~, and other sub-ingredient. In addition, in ceL1 walls constituting timber, bundles o aggregate of cellulose molecular chains dodge meshes exlsting in the form of sponge, and hemicelIulose are illed into a gap therebetween. Combination of respective compositions is c`ar~rLed~in a ro~m as stated~above. Further, bundies or !~m aggregates of ths cellulose~molecular chains are regularly arranged to ~orm crystal. 5ince this crystal is a linear high molecular having a cubic arrangement~af rsgularity and ~have many ~hydroxyl group, there is the state where regular hydro~en bond of hydroxyl groups are apt to occur between adjac~nt molecules~ In addition, 70-% of the ~., ent1rsty of cellulose are in such a ~state.~ Slnce such cellulose has a~high melting point of crystal and is thermalLy~dissolvsd bsfore fluid1ty~taks pl~aces even if hsat treatmsnt l S applied, it doss ~not svsntually cause ~ :.
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thermal fluidity, It is considered that such a property of timber, etc. allow a crack to be apt to occur by , movement of moisture, contraction of`tissue, and thermal i :".
decomposition of ctellulose. However, if chemical ~" .
modification to substitute acetyl group (-COCH3), nitrogen group, benzyl group,~or lauroyl group, etc. for hydroxyl group (-OH) of cellulose is caused to take place, internal plastlci ation takes~ pl ce in the tL~ber. ThUs~ ther~a7 fluldity i8 rendered thereto. Namely, ;it~is considered that if cellulose is changed to derivative and the degree of hydrogen band iis weakened, thermal fluidity is provided in~-~timber. It is; further considered that if there is aused to exist the state where crystal of the ce7lulose is~caused to have ~luidity, a~crack by contraction or a arack by~movemen~ of~moisture does not take place even ir hign ~temperature~hea~t treatment 1S impiemen~ed to sucn c~ell~lose.
As~ an actual method,~it is;~lmagined to utilize that;there~results t~h~e state wood;t:lmber the~rmal fluidity the~rmal plasticlty)~ by hydrothermal chemLcal reaction.
Namely,~ as a pre~-t~reatment process,~ ~an approach lS
employed to ;impregnate a specific Qrganic impregnant in timber to contain it in a high temperature water more than 100~~C to allow it to~ cause hydrothermal chemical reaction h~yd~rolysis) to take; place to dissolve a portion of cellulose or lignin, etc. in t~he wood; property to 2067824 ; ~
.!, ' '' "'' partially cleavage several chemical bonds, to change ester in resin to alcohol, or to implement haLogen subst~tu'tion ,~' . : ', of lignin aromatic nuclear to provide lignin chloride, :,.
etc ., th~s: to provide the s tate where the woady part has thermal fluidity'~thermal plastlcity). It is to be noted that it~ is, needless to say that in the case of carrying `out~high temperature~heat treatment more than 100~, thls ',~
t reat~e-~t is `not necessa~ily re~uired as a pr~-~rocessing hydrothermal chemicaL reaction), but rnay be carried out ", later in a manner dou~ling as a high temperature heat ";,~' treatment.
Then,~ the impre~gnation-t~reated timber, etc. aftér ,~
undergoing drying~tre~atmen~t is pLaced in t~.e atmosphere of ',, `incombus~tible ;gas~of~more than 90~, ~and an' AE sensor is `"';
àttache~on the'timoer~, e~c. ~, Here,~tha tar~ called "incombus~tibIe gas~ refers to iner~t~ or Lnactive~gas such as argon, krypton or helium, '~
e~tc~ or~mi'xed~gas inc~lud~ing one or two kinds o anmonium, ;' sul~fùr~dlo~ide,~;carbQn~d1oxide and nitrogen. ~ ;
Attachment~ o~ the AE~ sensor i9 carried out '';~
through a~ wave guidè~;by~ taking tempera~ure and humidity i,,;
ïnto consideration. The,attachment position of t,he wave '', guide~is the test,specimen cross sec~ion.
Then, an~ AE that timber,~ etc. produces in ',, accord~a~nce~ w~ith~ a~ change of~ the woody ~structu~e is ~ ', ,de~te~c~ted as an ~e~lectric signal to ana1yze its Lnformation~

`.`.- 2~7~24 .',' 1 ", i ~
to predict a crack of th~P timber, etc. :: The technology therefor will now be described. ` ' '' .For example, in the case of ~ carrying out .....
processing at a. temperature (160 to ~170Cj and a pressure ~.i ~,2.0 to 2.4 Ky/cm2) o~ a high temperature heat treatment '' (example 1) as shown in FIG. 1, AE signals sent from the ':
sensor fi~re sorted every amplitude classes. Thus, AE event numbers eve~y classes are represented as shown in FI~. 2.
AE~signals are amplified at a pre-ampliier and is then .;' subjected to sfeftting by a cracking mon1tor (more than lV '~
~at 80 dB). By amplifying the signals ~hus processed, the . .
: , , .
number of: AE: events:~ is detected. Recordlng of' such AE
event~ data is shown Ln FIG. 3, and recording of an .. '~
aocumula~ted AE:energy is~ shown in FIG. 4. ~
This~'case~shows the 'examoLe~o exFeriment where because the moisture~percentage prior tO ~treatment is l0 l''''~'~
to~ 12%~;and ~or other reasons~any ~U~crack~ does not take :place~in a test speciimen aft:er experiment.
:On~ the contrary, for example, in ~the c:as0 of - : ' 'carrying out treatmen~t; at~a temperature ~160 to 170~C) and à pre ~ure: (2.0 to 2.4 Kg/cm2j of a~ high temperature heat ~ -~
. ~ ' f: ,: ,',f~ ~ treatment (examplf~ 2) as shown in FIG. 6, when AE signals : `'.
s~ent~lfrom' the ~sensor~are sorted~every amplltude classes, ;':AE~event numbers every respective classes are reDresented ' ~.'' as;~shown in FIG. 7. 'I'hese'AE signals are~;ampLified at the 1~"
pre-~ampllfler to detect the number of AE'events more than ~

206~824 i~. ' . ' .
a set value at the cracking monitor. Recording of AE
event data of more than lV is shown in FIG. ~,-' and recording of an accumulated AE energy thereof is shown in~FIG~ 9. In this case, because~ the initial moisture p~rcentage is 28 to 33% and for other reasons, a crack~ tak~is place at the central portion of a test speclmen after experiment as shown ln FIGS.~lO1a) and (b).
By the A~ si;gnal data of the ~xperiment exampl~
(no~crack~ example) and the exporlment example 2 (crack example), it is possible to clearly specify the time point when the tlmbor, etc. is cracked durlng treatment and the condltlon~at~that tlmo.~ Who~n an approach ls employed to colloct a;large ~numbor of such test data to anaIyze them, it~ b2com~possible to predict a crack from AE data.
Namoly,~ even l~ attention is drawn ~to tho entire AE
slgnals, Yinc~ bocause t~hero are many nolse slgnals, it is poYslblo to cloa~ly recognlze a crack. However, whon AE
signals ~havlng an amplitude more than ~a fixed value empirlcally determ`ined (AE signals mor~ than lV at 80 dB
in~ tho cas~ ;~of ;the experimont ~example) are recorded, everybody can clearly recognize ~elativs rela~ionship with crack (FIG. 8?. In view of this, attention is drawn to AE
Yignals more; than a ~specific amplitude to c~nsider o~ccurrenc- of~t~hls slgnal as a ''warnlng of crack". Then, he~rate~ of o~ccurrences ~FIG. 8, FI~. ll/~) of a specilc amplltuùo~ (more than~ lV in this ~oxporiment examplo) are 20~824 ,i ; .

., ~plotted, and accumulated AÉ ~event numbers are plotted (FIG. 9, FIG. llq)~. When such events thus plotted~are collected to carry out s~tatistical processing by using the ':conditio~ such ~ as~ kind~ of woods, initial: moisture percentage, heat temp~erature, or plate thickness, etc. as a ~parameter, it :is made clear tha~ ~A~ signals above a ~ixed amplitude under a:predet~rmined condition indicate a crac~war~ing 1imi~ value ~FIG. 8, F~G. ~ ). Fur~her, i~
is ~pos~sible~to know tha~t there is:~no crack when wha:t psttern' of the accumulated:`AE en~rgies is: s~lected,::thus to speci~y a crack warning l~mit model pattern:. In view of~;~this,:~ an~ approaan~ is employed to compare the model pat~;tern~ o~f~: the~ speci'ied standard warning llmit A~
ccurence~rate and the:crack warning limit.accumulated AE
event:numbe:rs with~AB:occur~ence cir'Gumstances actually méasured'~and r~cordéd~to analyza the meaning o~ AE signals àt~that~ time:point~ 'thus to carry~out~predictive judgment of~a~crack:of éimber,~.etc. :;~
T;hen,.~this`~invention LS direc~ed: to a method~of mod~ifying,t~reatment of~:timber, et~:., which is~adapted to apply~temperature~so :that~i~ts gradient is~ not st~eep while controlling~the a.~mosphere so that no crack occurs in the timber, : etc . by using; ~ ~ temperature and humad;lty :as a control: factor on the ~basis: of the above predicted information, ~;thus~ ,~to carry:` out ~a predctermined high temperatùre~heat trcatment.

- .

~ 20~24 ::
.. ....
~ "4j Namely, in the case where predictlve judgment of crack is carried out from the AE data as described'above, r; ~' an approach is employed to inject a large~ quantity of vapor f~or ~a ~short time, or ~to stop~ the~operation Oe the '`' heat~ing unit to lower;temperature,~ ~y carrying out this :
, , ,:
approach, the atmosphere where no crack occurs in the ''' wood ,~ etc. is: provided.;~: :As a res:ult , generation oE AE is ''' s~opoed, or ~here r~sults the state where~AE is generated '~
at~a~ level less than~the~ crack warnLng stan~ard level cmpirically deter~ined.~ Namely, by using temperature ahd humidity as a control factor, Lt is possible to carry out '' the~atmosphere cont~rol ~by~ using temperature~;;and humidity "'~
as~a~ control~facxtor.~ The~relationship~ of temperature, ~'' thè~ humidity and the~ AÉ generation is shown in a model i'~
o~ in ~ FIG. 12 .
Further, it~` i5~ empiricaliy recognized that the~
main~ caus~e to gene~ate ~a crack in the high temperature '"
hed;~;`treatment~ is;~not movement~ of moistu~re, but c~ontract~lon~or~ expan's~ion by~ a sudden~temperature chanse.
'Accordingly,~wh~le~;gently~settirg the t-mperature gradient when~t~emperature i's ~appl1ed or ;lowered where a crack "~
occurS meet~s with ~this purpose, since the~limit value of ; '' the ~temperature ~gràdient where a~crack~occurs varies ~ , dèpend~ing upon the ~initial~ moisture percentage, the~kind i'~' of~woods;,~the~ plat~e~thlckncss, and the dev1ce, etc., it is required~ to ~mcasure~AE 'in'advance~under~a~predctcrmined ~' : . ~ .. -.

`: 2067824 i`:
. ~ .
.,.,, `,~
....
condition to set, at all tim~s, the accumulated AE energy increasing rate to a 1ess than a limit value (wari~;ng ,~
limit standard).
The change in the wood property by the high -~
temperature heat treatment will now be~ described.
Meanwhile, in the processing for implementing l ;
I' '.'`.
high~ temp~rature heat treatment to~timber, etc. in this i ;
Lnvention~ the strength is enhanced or ~nc-eased with respect to impact, oompression or bending by increasing lignin, and the tensile strength is weakened~or decreased by reducing cellulose. However, since the crystal of c~eliulose has a high~me~lting temperat~lre,~and is subjected to~thermal decomposition before placed in ~ thermal fluid j;~
state, no thermal fluid st~ate is eventually provided (FIG.
13~.~ Namely, tnis ~reatment is~featured below. By making use or a property such that ~timDer~does no~ cause a -`
thermal- fluid sta~e,~high temperature heat tre tment is further~ carried out und~r incombustible condition, i.e., in ~:the~atm~6phere ~of incqmbustible~ga6 atmosphere to completely remove ;moisture while retaininy tissue of a regula`r cubic arrangement as it is, and to harden or cure the enti~rety by thermal denaturatlon of protein or other ingredients. The wood~property i6 cured or hardened by this~ treatment, resulting in excellent weather resistance l`
or~ w~ter proof.~ On the contra;ry, the wood~ becomes ~'~
brlttle, disadvantageously~lovering workab~ ty.

- 22 - ~ ~
,, ' ' 2067~2~
........ i , .~. ..
., In this instance, in this invention, acetil group or nitro group, etc., are substituted~ for~hydroxyL g~oup of cellulose to change~ the cellulose to derivative to ~ ;;
weaken the degree o~ hydrogen bond, thus alLowing the woody part to have thermal fluidity (thermal plasticity).
This invention reLaxes curlng of wood property by this treatment ta improve brittlen~ess, ~and to recall tenacity or toughness in~rinsic r~ wood ~nus;~o impr~v work~bility suah as~ cutting~property, etc. ;
In the~ second invention for which the patent is~
;sought to be granted, an approach is employed to impregnate an organic impregnant, e.g., as oxyethel such as~ polyethylene gLycol or methyl sellosolve, etc., po;lyatomic alcohol, -phenole, natural rubber, synthetic rubber, or mixture~ including them in combination into va-ious vegetable workad material~ such as a ~log, a worked tLmber, or a bamboo s~tuff, etc.~to lmplement~im~regnating treatment; to cause hydrothermal ch~mical reaction hy~roly9i9)~ Thls pre-processing is~ the; same as that o~
the~ inve~ntion oe claim~
Then, an ~ AE ~ sensor lS ~ attached to the impregnation tréated timber, etc. to detect, as a signal, an AE that the timber, etc. produces in accordance with a ch~ange~ of` the woody~ structure to carry out informatlon proce~s~sing~of that signal to detect a crack;o the timber, e~tc.~ to conduct a heat treatment ~at~a~ temperature ~less ~ ?

23 - ~

, .. .;.

~ 2067824 ~

:,,, ,~
than 80C at a normal pressure while carrying out an~ j;
atmosphere cantrol so that no crack takes place in the ~ I;s timber, etc. on the basis of the predicted information, thus to implement a drying treat~ent. l~ `
I ~ . . .
As stated~above, also in the drying treatment process, by observing AE signaLs, it has beco~e posslble to always grasp the development circumstances in the course of drying o~ timber, etc.
Namely, signals sent from the sensor attached to the wood, etc. are ampLL~ied at a pre-ampli~ier, and a signals below a set level are cut at a cracking monitor.
Ater such signals are amplified, the number o AE events of a specific amplitude is det~ecte~. The AE event data of the specific amplitude is recorded ~FIG. 14). When this LS` illustrated as an accumulated energy, FIG. 15 is provided. The~procedure until.now is ~the same as that in~
t~he~ case of AE in the~high ;temperature heat~ tr~atment.
When a large number of such events are collected to carry ou~t~a stat~istical processing, a standard AE pattern ln a tlmber~d~ry~tre~atment process as shown in FIG. 16 can be provided.~

.
; .

~ 24 ~

2~67824 . -. ~
~;' , . . ~ .
In order to pred~ict ~ crack of t1mber, etc. from the standard AE pattern in the drying ~treatment, the following rule of exp~erience~-can be obtained.
1 In.:the case:where an AE signai above a ~ixed amplitude empirically determined appears, this is ! ~
co~ns;~i~dered:~as a~ precursor or:warning o~ a crack. .~.;
;; 2 The dr~ing ~process is comprised of three .
s~ta~ges. It is~important to va~y criterion`~e~ery stag~
: It is~:conside~red that the first stage (I) is the s:tage; where vapsr ~is infiltrated or penetrated into thc centra} portion o~timber, etc., and the temperature and thc~molsture;percen~tage become uniform, whereby drying is~
gr`adually~dcvelopcd.~ The mo~isture;~percentage at the tii e when~ he~:first~ a~nd~second stages are divided i5 25~, and 1 .
cor`responds~to a~f~lbcr (tissue) saturation po-nt ~abou.t 30 to:~25~%;~ At~a ~point~above :thc fibcr saturation point,~
mois:ture`~in`: a~:liquid~ state exists in timb0r.: At this :~
st:age~s:ince~;cr:aoK~ i~s ea5y~to~0Ccur,~attentio- must~be suff'clc~ ly ~ awn.~
;Fu~rthér,~ it :is~consid~ered:~th~at~the second stage s the st~age~wb0re~moisture~abso:rbed~in~;the form of a ~ ~
c~omb~ined~watcr~lnto the tissuc cuts: the bond, and begins~ :, vaparization~ Aic dlngly, : an ~ energy~ ~requircd for~
duclng~ the~m lsturc~percentagc ~bccomss larger~ than that at~the~ flrst tagc~ It~ls~ con~sidersd~that:~:thc tensile str:ength~::o~: t~é~wood~ suddenLy increases at this~:stage, ~ ~ .

2067824 ,;i .... .
......
. .
thus to have the ability to tolerate a drying condition more severe than that at the first stage. Accordingly, a drying condition~more severe than that a~t the ~irst stage can be applied,' NameLy, at the second stage, it is possible to apply a dry condition more severe than that of 'this expe~iment. Thus, the drying time can be shortened.
The boundary between the second and `third stages corresponds to aDou~ of tAe moisture percen~age. Th~
state of the' ~moisture percentag~ o~ about 15% is considered to 'an equi1ibrium moisture percentage, and corresponds to the air dry state.
` Sinoe ~there are many AE of a~small amplitude at the ~third stagel~ Lt~ is considered that~the phenomenon that orystal water ins~ide the cell is away from the cell takes place~. ~owevqr, since this AE o~ small amplitude is nat complete1y related to a crac~ by drying, it is surficient to set the drying~condLt:on~irrespective of the number of E~ even~s.~ Accordin~gly,~` a idrying conditLon setting furth~er more seve~e than that at the secondistage can be made~ at the thlrd~l~stage. By this experlment,~the drying t~ime~can~be~shortened.~
In this~way,~ when the dry state L S developed and the~mo'i~sture percen~tage~becomes equa~l ~to~a value Less than lO~ the~ numb;er ~of~ ~: AE of ~sma~ amplitude is also decreased.~ Once: ~ t~here resul~ s i such a s~t a te, the~ hea t 'conditlon~ is caused~to`be~severe by;f~ar to shift to a high ~: :

~ ~ 20~7824 ~
,,.i,. ; ~;-i .;
.., .."-,.
, . ..
f: : temperature heat state. ~ '' Accordingly:,~the method of predicting a-'"cr'a'ck"
n~the~drying process comprises:~discrlminating at which ' ~ drying stage a present stage:is present while monitoring the AE occurrence rate and the numbe~ of accumuIated :: : ~
events'by on line, comparing the discriminated state value with the:standard AE occurrence circumstances empirically dete~ined ~E~occurrence rate and~ AE accumulated ev2nt .:;
number), and the ~crack warning~ refe~ence value,; thus to ~`~
:carry aut predictlve iudgment of a cràck in the process o~
treatment. ' : : ' ~ :
Then,~ an:n~approach is~ employed to control the ' ;'.`
temperature condit:~on~and the:humidity condition by using, ...
:.as;~a:reference, an~:`:optimum ~ontrol pattern at that stage ~ ' emp~irlcàlly~dete ~ Lned~on the'basis Oe the crack predicted ~ .''.
i:n~format`ion to e~}ect a control to'relax tne atmospneric conditio:n'~so:th~t ~:no cra~k takes ;pl2ce,::0r to aillow the temperature'~co~ndit:ion ~and the humidl;ty condLtion to be se~ere~ co ~that ~there;~is ~:no:' loss~ Ln~ the t'reatment .
e~fl~clency.~ In this way,~a crack ls~predlcted by analysis '.~
of:;'~AE ~slgnals:~to;~carry ou:t: drying treatment while 'l~;
conducting ~t,he;!:atmosp:heric control by using the. `'.' t~emperature ~and; the: humidity as~a ~control factor to:dry .~''.
the'~.wood~so~that~the'molsture~ ~ercentage~o the timber, :~
etc~.:becomes equal~to a`~value less ~han lO~. In: t he h igh -~
temperature heat;~treatment of the~next process step, since ~1'., ; ~ ~ . . ;

2067~24 ...
,......

.......
material is difficult to be cracked according as the degree of drying becomes~large, and the ~materia~ is'not cracked even i~ the gradient of temperature elevation is reLati~ely steep, lt is desirable to dry the wood, etc.
ulltil the moisture percentage thereof becomes equal to a vaLue less than~ ~10~ thereafter to carr;y out high temperatu;re heat ~treatment.
Subse~uently, the impregnhtion treat-d dri.-d t~imber~, etc.~ is pLaced in an incombustibLe gas atmosphere more than 90% to carry out high t~mperature heat treatment more than lOO~C. When timber,~ etc. is placed in such a hLgh~ temperature state,~ slnce it is carbonized, it is re~erable~t~ place it in an incombustible gas atmosphere.
Also in this instance, an approach i~ employed to 1. ~ ~ , . .
attach an AE sensor to the timber to detect, as a signal, I;
A~ that the timber,~ e~tc.~ produces ln~ accordance with chànges~ -n~the~w~od~y~structure to~carry out information ;processing of that signal to predict a arack of the~ !','~'~,;''~, tLmber~, e~tc.lto carry out~high~temperaturé heat treatment mor~è;~than~10~C under~ a~high pressure or~a normal pressure while~conducting the~atmosphere control so ~that no crack takes placé, by ~U51119; temperature and humidity as a control factor~onl~the~ basls~o~ the predlcted ~inEormation.
The second invention ~is dlrected to~a~method of modifying j~
treatment~ of wood,~etc. in whlch~the above-mentioned approach is adopted. ~The method of predicting a crack~of 28 ~

, 206782~
`:

~imber, etc. in this high temperature heat treatment is the same as that of the invention of claim 1~ Namë~y, ,:
since occurrence of AE signaLs having an amplitude more ~:
than a predetermined width and a limit value of the temperature gradient where a crack occurs vary depending .
pon the ~initial moisture percentage, the kind of woods, the plate thickness, and the device,~ etc., it is j' . . .
preferable to ~easure: in adv2n~s.~E u~nder~ a preA~tf_rmined~ ..
condition to speciy~a limit of crack as;a warning l.imit re~erence vaIue from the AE occurrence rate and the .:~
accumulated AE energy increase rate to compare it with AE...
oc~curren~ce clrcumstances actualLy measured t~o complete the high temperature heat t.reatment while maintaining it at a value~les~s than a limit ~alue~at all times, Namely, ~he~ in~ention o~ this appiication is ~.
direc~ed to a met:hod of first carrying out impregnating treatment to predict~;a ~crack of ~he timber, etc on the .f ba~sis::of AE signal:to dry the tim~er while controlling the :
atmosph~re so ~ that~no crack takes plac by using ::;
te~p~era~ure and humidLty as~a control factor on the basis o:f predicted~ information:to subsequently carry out the ., ~ .
:~ ~ high temperat~ure heat treatment in consistency. .:
It is to be noted that FIG. 17~:shows,: in a model form~ ~:a standard AE~ occurrence pattern of the modifying tre~at:ment~of tlmber, etc. for carrylng out in conslstency such~ùry treatment;ànd hlgh~temperature ;heat treatment.

: : ~ ~ . .
:

, . !i~., , ' ' ~
2 Z0 5 7 ~ 2 ~
: `

The third invention to which the patent is sought :
to be grarlted is directed to a :method of mo~if~ing ..
treatment of timber characterized ln that "the method of :
detecting an AE as a signal to carry out information ,;
processing of that signal to predict a crack o timber, I;
et~. to control the~atmosphere so that no: craZZ_k takes ~.
place 1n the ~timbe~r, etc., by using temperature and ;humidity as a control factor", which is described in the ~ :
above-mentioned first and second in~ention is modiied as: ~$
o110ws. Namely, in the third invention, an approaZch is employed to detect an AE as signal to discriminate ,~
;amplitude of those slgnals from the~ total count number o AE ~ to recognize:~AE~slgnals hav1ng an amplitude ~greater than:~a pred~etermined value as a dangerous signal for crack ~
o ~further~carry out ~ monltoring o~f the~:number of accumulated AE eve~nts and AE occurrenGe race to dlscr1minate at which stage a present stage is an initial, : ~.
:medium~or later;s~t:a~ge, or whether or~ nct:~a ~present stage .
is~at:;a~h~igh~temper~a~ture heat treatment stage to predlct a crack :while;: comparing ~it with a reference: value at the ''j~.
discriminated trea~tmen:t;~stage to con:trol~temperature and ~ ,.
humidity on the basis of predicted information to carry~
out the atmosphere:s~o~that no crack occurs~:~in the tlmber:, etc. ; A model pattern of heat temperature/moisture : ~ ~
percentage, an~accumulated ~AE energy ln~:;that;~1nstance~, and ~ ~ .
:AE occurrence rat.e::standardized. at the t~ime of high j! ~

,:
: _ 30 ~

2 0 6~ ~ 2 4 temperatu;re. 'heat treatment~ is::as ~shown in FIG. ll.
; Further, a model pattern of~temperature/moisture rate an ac~Gumulated~AE~energy~,in~that~c~ase~, and AE~occurrence rate s'ta;ndardi~zed at the time o timber~drying treatment is as shown~ in FIG. 16.:~ In ~;addition~,: a model~ pattern of tempe:rature/moisture:,perce:n~tage,~ an accumula~ed AE energy :in ~that~;inatancé,~ nd~an~AE oc¢urrence~ rate in:the case~of carrying:~ out~ in~ cons'ist~ncy~dry~treatment ~and high tempe~ature,:he~a~t:~t~rea:tment i5 as shown tn~ FIG. 11. Since~
the wa~:,or~:method;'o~:~récognizing~a~:dàngerous ~ignal by an ,amplitude ~`fram measured AE signals, the way of dlsc;r~imLnat;~ln~g~ betwèen;~;.treatment:~,st~a:ges, ~the way of pre ~ ~t~'ng ~a~ c~ra,ck,~ and:~the~ way of~ control~ling the atmospher'e~were, alréady described~in~detail ln the~ first and~ sec:oqd inventlons, the~ir ~ explanat~on ~ is omLtted h0re.

R:IEF~.D~SCR;IP ION OF~ H~ DRAWINGS;~
~ F G.~ i~s~;a~ ~ ph~in~whlch~ temperature:an:d pressu !(1J,~ ` 0~ e.~ h' g- ~:tem era~,ur :~heat trea~tment~(exampl:e 1) are d ~FIG~ 2~-is 'a~'g~raph ~in ~wh~ich :~AE~ event~ number occùrrence:~ rate~ eyery~ ;amplitude~classes~of the high:~
tempe;ra:tureihea~ reatme~,n~t~example l)~ls~recorded, FIG. 3 is~a graph~ in~:which ~AE~ occurrence rate of:~an amplitude more~than. ~lV~,o~f~ e~ high ~:;temperature h`at treatment .ex,ample 1~ FIG.~4,~is~a graph in~ whlc~h~an~accumulated~AE
energy.~ of:~ an:~ ;am~ tude ~more ~than~ lV~of: the: high : 20~7~24 ~;

,i ,.....
......
...
tempera~ure heat t~eatment (example 1) is ~recorded, FIG.
5(a) is an explanatory view showing the state of'a test -',"
specimen after experiment of the high temperature heat 'i~
_. .
treatment',(exam~le 1), and FIG. 5(b) i5: a cross sectional ~"''~
.....
view showing the essential part thereof.
FIG. 6 'is a graph in which temperature a'nd '~
pressure of the high temperatu~e heat treatment (exampLe 2~ ar~ r~cord~d, FI~. 7 is a g_a?h 'n which .~E e~enr l;,~,' number (occurrence percentage) every amplitude classes of '~
the high temperature heat treatment (example 2), FIG. 8 is ,,~
a graph in whish AE occurrence rate of an amplitude more ~'i th~an~lV of the high temperature heat; treatment (example --2)~ FIG. 9 is a~graph in which an accumulated AE energy of~ ;,~,' an amplitude more than lV of the high temperature heat treatmen~ ;(exampLe 23 is recorded, FIG. ~lO~a) is; an "~
explana~ory view showing the state Oe a tast specimen ,~
af ter; experimen- of the hlgh~ te~perature heat treatment ',"' (example 2j, and FIG. lO(b) is a cross sectional view showing the~essentiaL par~ thereof.
FIG. 11 is an AE occurrence model patter at the ' time o~ hlgh tempera,ture heat~ treatment, FIG. 12 ~s a ',~
model view showing temperature/humidity control and AE ''~
occurrence, and FIG. }3 lS a graph showing changes in the , wood~ property ~at ~the time oE ~high ~temperature heat ', treatment.
FIG. 14 ~is a graph in which~temperature and AE

..
, ~ - 32 -: ~ ': ' ', ' - 2067~2~
....
..,~.

: occurrenGe rate of an amplitude more than lV o the drying ,", treatment ~exampLe F3) is re~corded, FIG. ~15 is ~a ~3rap~'in, which accumulated AS~energy of an amplltude more than lV ~,'"
of t~he~drying treatment; (example 3) is ;recorded, FIG. 16 '~,''',', shows~ an AE oCcurrence model pattern at the time of high ~r ;~ t~emp~erature heat treatment,~ FI;G. 17 shows an~AE occurrence "', ~"~ model~pattern at~the time of drying/hLgh temperature heat tr~atme~nt,~ FIG. 18~is ~a graph in which a temperature change;~;of the~ high ~eemperature heat ~treatment in the I"s'' embodiment 1 is recorded, FIG. I9 is ~a graph in which AE ',',','',' event number (occurrence rate)~every respective ~mplitude ,,' class-s~of~aA~un~pr~ocessed~material. IFG.~20 is a graph in whi'c~,AE~event~ number (occurrence rate) every respective ,''"' ampli~tude~ cla~ses~ Oe ~the impregnation tre'ated material oi ~ 'I'i,,'~, '",~ ;the~ emboidment 1 is~recorded, FIG. 21 is a graph in which ;~
,AE~occurrencè ~rate~'o an~amplitude more than lV or the ~ ,',,',' 'unprocess~ed or~non-worked material of the~embodiment 1 is ~ "' ;recorded,~FIG.;~22 is~a~graph~in ~which AE occurrence rate `,'' -o~f~ an~ amplitude'morP~;than lV of the impregnation treàted ma~teria~ of~; the~ emb'od1ment~,1 is ~recorded,,FIG. 23 is a~
graph~ n~which~;àn~accumulated ~AE~energy~o~an ampIitude morelthan~iV;of the unprocessed or~non-worked~material of ',~, the~ embodiment ~ is~re¢or~ded, FIG.;~ 24; lS~ ~a~graph in which accumulated AE energy,of an amplLtude more than~lV of the~ ~ '',,' mpregnation ~,~t~reate~d~material, of~the ,enlbodiment 1 lS ',`
reco'rded,~ ~IG~. 25~'~is ;a graph showing~an~;AE occurrence ~ 'f;

2~5782~

. ..
.....
~ model pattern and a crack limit control reference by the j ;
, ., accumulated AE at the time `of high témperature hëat treatment of the embod1mènt l, FIGS~. 26(a) and ~b) are l~
explanatory views showing the state of a test specimen ;
before and after the high temperature~ heat treatment lj according to tbe emboidment, and FIGS. 27~ai) and (b3 are ~','.''j!', explanatory views showing;a cutting test state of a test ` !,';
timber subjected to tempe,a.ure heat treaitment according !1~
to the embodiment 1. ~ i,''~!

: ~ ~'''.,.';
Best Mode for Carrying Out the Invention ~, Explanation~ wilL now be given on th0 baisis of ~in embodiment for~explalning this invent~on in more detail.
Embodiment 1 A naturally dried ~moisture percentage 30~) naturai raw tlmber log material (lengrA or 200 mm x d~iameter of 80 ~ ) o~a maple treP is prep~red. This log, materlal is first d~ecompressed at~ a room temperature to carry out deaeration ~in ~the timber thereaftQr to pxessure~
in~ect~ polyethylene glycol at 3 to S atm by a pressure pump. Then, the ;impregnated tLmber is lnserted into a high temperature~ water more than 100C to cause .ydrothermal chemlcal reactlon. It lS to~be noted in the case of carry~ing out high temperature heat treatment more ;~
than~100C, this treatment is not~necessarily required as ., ~ the pre-~process~ing (hydrothermal chemical reaction), it is ~
.

~ i - 34 - i :: ~ , ,, 2067~2~ `

.. ....
a mater of course to carry out it in a manner doubling as `~
a subs0quent high temperature heat treatment. The log material pre-treated in this way and the same log material : .. .. .
~ which has not been pre-treated are admitted into a thermal , ."::
treatment charnbe~, and an AE serson is attached to those i; ;
materia~ls through a wave guide. In actual terms, the thermal treatment chamber internal side terminal of the wave guide is ~ixed to test timber section by means of wood screws. The wave guide ls extented to th~ outside passing through a measurement hole provided in the thermal , , : , ! . ~"
treatment chamber. The AE sensor is attached to the externally extended portion of the wave guide, and is : : .
connected to a pre--ampliier, a cracking monitor, and a personal~computer installed ln~ the~viclnlty therewith. ~`
Then,~air is deaerated from the thermal treatme~t chamber~ 1 and nitrogen gas is lnjected or lntroducted from the incombustlble gas ~Lniection unit ~to; provide an incombustible gas atmosphere o~f 47~. After such a state lS~ pr~ovlded,~ thè~thermo-couple;ls ~caused~to be ope~atlve to Lncrease the temperature wlthin~the heat treatment ~ :i chamber, and ~to inject~ vapor from a~vapor insertlon unit,~
t~hus to adjust humldity inside the chamber. As shown in FIG. 18, the teZ~llperature is raised up to lS0C at a stroke ~ ~`
to;c~arry out~hlgh temperature heat;~treatment of about lS0 to~160C for 22 hours thereafter to lower the temperature Z /:
to a normal temperature in about two~hours, thus to ~: . . : : ~ ; ' '` ., ~ 2067~24 ~

j ........
'complet~e~ the treatm~nt 'in about 2 hours.~ Occurren~ce circumstances of AE~for that time period was observëd.
1,, j, j FIG. l9 shows AE event circumstances every respectlve ~amplitude classes ; of the untreated material in that instance. On the contrary, FIG~ 20 is a record indicating i' AE event~ occurrence circumstances every ~ respective 'i'~
~ , . . .
amplltudes of the impregnati~n ~reated material. In both case, since~ther~e a great ~uan~i~y of A~ sign21s wh~ch are n~t related to crack, it is impossible to specify at which time point cracks occur. In view o ~this, when an approach to specify AE having an am'plitude more than lV
with~;the ampLification fac~tor being as 80 dB within one minutes ~to m~ake ~a ~rscord, AE event occurrence circumstances of ~the;~untreated mate~rial'are as ~hown in 'FIG.~;21, and~AE event occurrence circ~nstances o~ the mpregnation ~rea~ed~ma~erlal;are ~as shown in cIG. 22.
Thus, lt h2s~ been~ possible to~ conslderably clearly recognize ~E'signals~ reLate~ to crack~ When one reads these~graphs, the~untreated material and~the lmpregnation reated ~ ma~terial ~both~ have the followin;g tenderlcy.
Namely~ at the~lnltLal stage where tempe-a~turs within the heat treatment~;chamber rlses, a great;quantity of AE are produced. ~ At the~intermediate sta~te,~ ~there is hardly accurrence of AE.~When~the tempera~ture~begins to lower, AE~vents~ take ~place~: ~or a second time.~ However, the occurrence circumstances; of the untreated~ material and , :

.

20~7824 , j ~';' ....

those of the impregnation treated material are extremely , ~ . ... ..
differe~nt from each other. In the case of the impregnation treated material, there results the circumstances ~here AE hardly takes place. Namely, this .",;, clearly teaches that a crack takes place at the initial ., stage o heat treatment in the case of the untreated material, whereas no~crack takes place in the case of the impregnation treat~d material. '~h~n compariaon bet~een FIG, 23 (untreated materlal) and FIG, 24 (~impregnation treated material) indicating ;an accumulated AE ~nergy is made, the above teaching is more clearly recognlzed.
In view of thLs, in the case of~implementing high temperature treatment to timDer easy to crack as in the case of the untreated material, it is required to predict a crack to control the ~atmosDhere. Its control model is as shown in FIG. 25. NameLy, an approach i5 employed to etect Ar as an electric signal to carry out to record and/or analyze that data ~y means o~ the personal computer to compare the result thus analyzed with a reference value empLrically set in advance, thus~to predict a crack in the tlmber, etc. More particularly, ~an approach was adopted :,:
~ to record AEs having an amplitude more than lV with the ~ : , ampllfication factor~being set~to 80% wlthin one minute to udge the present clrcumstances to fall~within a warning ~ ~`
zone~of crack when the accumulated~event;number is~above a reference value, or~ when the amplltude is above a ~;

, ....

:: :: : : ,:, ` ,. ..

~ ~ ;

referencs to allow the: vapor injection unit to be operati~e to in]ect a large quantity of :vapor into'the heat treatment chamber in a short time to ad~ust humidity ~ "
in the heat treatment chamber, and to control the operation o~ the heating unit to ad~ust temperature withln the heat treatm~nt chamber to control the atmosphere so as to main~tain the state where no ~AE takes place rom the imber,~tc., th~occ~r~_~ce~s'ste ~he~e~ha AE s~n~' ls below ~a predetermined re~erence ~o allow the heating unit to be operative while ca~rying out such a .controL of atmbsphere to gradually raise the temperature within the heat ;trea:tment chamber, ;~thus to. carry out a high :temperature h:eat treatment for four hours at ~160 to 180C
so~that no crack takes~place in the timber, etc.
5 a:r~su~l~t, ln~ ~he case~ o~ the impregnation treated~ ~.a~er~ a~ s~tisfoctory modifyi.ng treatment implèmented product in ~the:form of lignite or ~ossil wood was~:mad~e~.~up., Re~erence photograph 3~ shows.this. In the cas~ :of~the~ mQdif~ying: tre~atment~:implemented. timber sub]~ected~to ~lmpregn~ati~n high temperature heat treatment, any ~crac~does ~not~t~ake place. On the c~ontrary, in the case of modifying:~treatment implemented timber which is not :sub]ected: to high temperature heat treatment, a large number~of radial crocks were confirmed.
; Then,~:comparative study on ;cutt~ing property in the;~wood ~sect~ion o~ the ~timber ;subj~ected to modifyLng ~, ~, ~ - , , .

2~67824 ,. ...

. .......

treatment in the form ~o~ lignite or fossil wood was conducted. Al, A2 and B1, BZ of reference photographs 4 show the compared~ results. In connection with the impregna~ionjhlgh ~temperature heat treatment~ implemented timber and the high temperature heat treated timber which is not subjected to impregnation treatment,~a cup byte of a~lathe~ is used to.carry out cutting of~the waod section ; ; at ;~L580~rpm.~ As ~a ~result, in the case~o the ~o~er mpregna~ted/high temperature' heat~treated timber, cutting quality Qf an edge tool ~;is improved, and chips are successive in a belt shape (A1 of reference photograp 4).
The cut~tiog surface~ is ~smooth. ~ ~ Thus, tenacity, orkability~and~strength~intrinsic to t ber are reaalled.
On~ the ~contrary, in the latter non-impregnated high em~era~ure~ hea~t tréated timber,~chip is in~the ~orm a pawder ~BL of reference photogr~ph ~4~ and the cutting 'surface is~rough~ 82 ~of referenc photograph~41. As s~tated~above`,~ in ~the ~case of ~the impregnati~on/~high 'temp~erature~heat t~rea~tment~implemented~timber, brittleness ~which~was the d;rawback~in the prior~art~can be improved to much dègree, ~and chisel~/planér work1ng, ~ woo~d lathe ; working,~ general wood ~machine planer, -~ood screw/nail 'fasteni~ng~working can~be;sufficlen~tl~y~implemented thereto.
Acco~rdingly, such ~ impregnated/h~igh temperatùre heat~
treated ~timbe~r ~can~be~ used~ not~ only ~for artis~tlc~
hàndicrafts but~ ~also~ furnitureu~stuff, building or 2067~24 .....

.

construction materials, rooing materials~ or marine boards, etc.
'~ ~ ' ' ' A~
Industrial Applicability The ~irst invention of ~his application resides in a method of modiying treatment of timber, etc. of impregnating ~a specific impregnant into timber, etc. to allow hydrothermal chemical reaction ~ hyarolysis ) to ta~e place to lmplement high temperature heat treatment to the timber, etc, in the~atmosphere of an incombustible gas, wherein an approach is employed to detect acoustic emission that the timber, etc. produces acoustic emission in accordancé with a change o~ the~timber structure in the high temperature heat treatment to detect~ a crack of the tlmbe~r, ~etc.~ thus to ~carry out high temperature heat tre~atment~while c~ontroiling the atmosphere so that no~
crack~occurs ln the timber~, etc. by using~temperature and humidity as a control factor.~ ~y impregnat~ion o~ the organlc impregnant, thermal plasticity is rendered to wood property.~ By the~high~temperature heat treatment;in the atmosphere of~an incombustible gas, the property o the lignite or fos~sil wood is rendered thereto~ In addition, durlng treatment, an~ atmosphere ~control using AE as a slgnal, ~a~nd using temperature and humidity as ~a control factor is ~ca~rried out.~ Accordingly, when the above effects~are~ combined, any crack during trea~ment becomes ~ ~, ~ 40 -' ~2 0~ 3 14: 01 sEgO3 345~ ~4~9 ~ Ql 002 i 1 2067~4 1~ TABl~E 1 ~, USE OP ~:G IE!!P~I~ E~ IRE~T~ ll~ER

1; ~ , .. . _ _~ _ ._ . . _. _ USE, ~ PRQPEEm ~ A B C
,~ . ~ : : : ,, :
_ .. _ ~: : ~SlIC ~NDI(~FIS; : ~ ~ O (:) ~
~ : ~ :: ~:
: ~: USE . F[ENnU~ ~A~S :~ 0 :: ~ O :
; : ` ~ :: , .
: BUI~DING II~IEBI~LS : 0: x C) :~ ~ : : ~ ~ ~ .
': ~ 9Q~ ~ o X : X :
_ _ _ ~- _ ;~ COLORING:~PROPEE~ O x x ~N~IONAL ~ . DlbiENSI~ Sr~BIL~ ~ o !~ X
~ ~ C;~: ~ ~ ~ ~
',~,`,i;`:`',~ ~ ~ ~P~ : ~ ~o ~ :X

~ ; ~ ~ : ~ ~ , ~: ~ i~ E~SEhT P~lY ~ ~ ; O ~ X
.. , . ,. ~ , . _.. _ _ ' j ~ ~ , ~ , ~ ~ S~i~``~ SCI~ ^ G ~ ~ :
~ ~ ~ ~ :: : ~
:,~,~ 011;11~:(E~;, S~ ~ o x 0 ; ~ ~ERI~ ~ ~ : :
`~ `~ `F~G~ ~C

~ , . ` _ . ~ .............. .. _ _ .. . _ _ _ i;~ B~;NON~3,H~GIE~II~HEATIRE~I~TIMBER: :~

~ . ~

~` 2U~:7824 ~
,, null, 50 the tlmber, etc. is caused to have a peculiar woody property. Thus, the workability is improv~e~ ~o much extent, and the range of use~becomes broder~than that in ~ " , . .
the prior art. ~ '~
The second lnvention of this application resides i'' :: : : , 1 '~;
in a method of impregnating a specific organic irnpregnant into~;the timber, etc. ;to alLow hydrothermal chemical re~ction ~hydrolysis) theréafter to carry out a heat drying process. During this dryirlg treatment, an approach is employed to detea~AE as a signal to predict a crack of the timber, etc. to carry out atmosphere control by using temp~e~rat~ure ~ and ~humidity~ as a ~ controL factor.
'AccordingLy,~ there~ is~;har:dLy crack during treatment. When the degree of drying~;is developed to a level less than 10%
in~thls way,~ the~impregnated~t~imber,~ etc.~is subjected to hlgh~temperature heat ~treatment in the a~mosphere or an ncombustibLe gas~ to~ re~d~er the~ p~roperty of lignite or as~sil~ wood. Als~o ~in th'is instànce,~during treatment, ~n ;approach~is~employed~to~detect AE as~;~a signal to predict a crà~k~of ~timber,~ etc.~ to~carry out atmosphere control by us~ing~temperature;and~humidlty as a control factor. ~ By adopting~such, an approach, even lin the case~ o~ the t re a tme n t f r om ~ g re e n t imbe r hav i n g a ~ h i g h mo i s t u r e perc~entage,~ it~ is po~ssible to carry out in consistency drying ~t~reatment~and~high ~temperature~ hea~t~ treatment~ln 'the~state where~there is hardly crack during treatment.

- 2~7~24 ~

, .: . .,~
. .,:.

As a result, it has become possible to prevent lowexing of. :
yield in the conventional high temperature heat.treatmënt, and to improve the quality~ of the high temperature heat treated timber.
The third invention of: ~his application resides l~.
in a method:basqd on the methods of the first and second 1~:
inven~tion wherein. an~approach i9 empLoyed to detect AE as a signal to analyze it to:pr~dict a crack to ca~y out 1 .
::high temperature heat:treatment while preventing a crack by conducting the atmosphere control. Particularly, this ::
third invention is characterized ln that an approach is employed:to ~have the~ abillty of prsdicting ln advanoe a !~
:crack of timber by~ anaLysis of AE. By adopting this ,.`;
:approaoh, it has beoome possible to industrially and ~' e~ficiently mass-produce ~imber, etc. having good y~iel~ ;
an~ free ~rom~crack.~

- ~ . , , ; .

~;, : ,:,, : - : :: : - 42 ~

. .
":

Claims

Claims:
(1) A method for modifying treatment of timber and other wood products, which comprises the steps of:
impregnating an organic impregnant, e.g., oxyether such as polyethylene glycol or methyl cellosolve, etc., polyatomic alcohol, phenol, natural rubber, synthetic rubber, or mixture including them in combination into various vegetable worked material, etc. such as a log, a worked timber, a bamboo stuff (hereinafter referred as "timber or any other wood product") to allow hydrothermal chemical reaction (hydrolysis) to take place, thus to carry out impregnating treatment, and allowing the impregnated timber or any other wood product in the atmosphere of an incombustible gas more than 90% to attach an acoustic emission sensor (hereinafter referred to as an "AE sensor") to the timber or any other wood product to detect, as a signal, an acoustic emission (hereinafter referred to as an "AE") that the timber or any other wood product): produces in accordance with a change of the timber structure to carry out information processing of that signal to predict a crack of the timber or any other wood product, thus to carry out high temperature heat treatment more than 100°C
under a high pressure or a normal pressure while conducting an atmosphere control so that no crack takes place in the timber or any other wood product, by using temperature and humidity as a control factor on the basis of the predicted information.
(2) A method for modifying treatment of timber and other wood products, which comprises the steps of:
impregnating an organic impregnant, e.g., oxyether such as polyethylene glycol or methyl cellosolve, etc., polyatomic alcohol, phenol, natural rubber, synthetic rubber, or mixture including them in combination into the timber or any other wood products, attaching an AE sensor to the impregnated timber or any other wood products to detect, as a signal, AE that the timber or any other wood product produces in accordance with a change of the timber structure to carry out information processing of that signal to predict a crack of the timber or any other wood product to carry out heat treatment less than 80°C while conducting an atmosphere control so that no crack takes place in the timber or any other wood product, by using temperature and humidity as a control parameter on the basis of the predicted information to implement drying treatment, and subsequently placing the impregnated dried timber or any other wood product in the atmosphere of an incombustible gas to attach an AE sensor to the timber or any other wood product to detect, as a signal, an AE that the timber or any other wood product produces in accordance with a change of the timber structure to carry out information processing of that signal to predict a crack of the timber or any other wood product, thus to carry out high temperature heat treatment more than 100°C
under a high pressure or a normal pressure while conducting an atmosphere control so that no crack takes place in the timber or any other wood product, by using temperature and humidity as a control factor on the basis of the predicted information.
(3) A method for modifying treatment of timber and other wood products wherein "the method of detecting an AE
as a signal to carry out information processing of that signal to predict a crack in the timber or any other wood product to carry out an atmosphere control so that no crack occurs in the timber or any other wood product, by using temperature and humidity as a control factor", which is described in claim 1 or 2, is implemented by detecting AE as signals to discriminates amplitudes of those signals to consider an AE signal having an amplitude more than a predetermined value as a dangerous signal for crack to carry out monitoring of the number accumulated events of AE and the rate of occurrences of AE by on line to discriminate between a drying stage and a high temperature heating stage to predict a crack while comparing current or present values with reference values at the respective discriminated stages to effect a control by using temperature and humidity as a control factor on the basis of the predicted information, thus to carry out an atmosphere control so that no crack occurs in the timber or any other wood product.