Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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:~ DESCRIPTION
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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
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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
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timer~or~bamboo material, etc. at a high temperature in
the atmosphere of a incombustibLe ~as to process or work
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: 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 ~ -
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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
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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
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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
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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
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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
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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
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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
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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:
. ~ :
;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
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produced similarly to crack by drying. Further, it is
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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. ; '"'
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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~ ~,
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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,
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~ ~ 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
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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
3 5
~: . . : : ~ ; ' '` .,
~ 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 ~;
, ....
3 7 -
:: :: : : ,:,
` ,. ..
~ ~ ;
2067824
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 ~
. .
":
