Note: Descriptions are shown in the official language in which they were submitted.
~83~6
1 The present invention relates to surface treatment of
~tones, and more partlcularly to a method for protectin~ the
stone surface from being soiled, faded, discolored, weathered
and erorled by means of particularly applying a particular
protector a~ent, and so treated stones. According to another
aspect of the invention, it relates further to a method for
coloring the stone surface by adding a coloring agent to said
surface protector agent, and ~o treated stones.
Various natural stones have been used with various purposeq
for a very long time. Above all, marbles, ~ranites and the
like stoneq have been used for interior and exterîor building
materials s~ch as flooring, outer and inner wall materials,
furnitures such as de~ks, mantelpiece~, bath tubsJ benche~,
monumentq, tombs and the like, in view of respectively beautiful
colors and patterns, good sence of touch, hi~h strength and
durability and other preferable propertie~.
Such stones have crystal ~rains and consequently fine
gaps or chin~s between ad~acent cr-g~tal ~rain the dimension
of s~id ~ap bein~ varied from ~e~eral microns to ~everal tens
of microns and the total volume of ~aid ~ap~ being arran~ed
frorn C.l~ to G.7~ Or the totai volume Or the stone, so that
various alien matters are apt to penetrate into ~uch ~aps which
cau~es soil, fadin~ and discolorir,~l. Thi3 is particularly
stri~ing in the case of ~Jround and polished stone surrace,
which may be observed for instar~ce on the cor-idor floor
covered with marble stone plates. ~aid cr-yst~l ~rain gaps
can be a cause also of weatherin~ and ero~ior~ of the stone
during the lapRe of a long time above all whe~ such gtones
are used for outdoor str,~ct~res, which na~- be ob e,ved for
3~ instance on the old bench maae o~ C~ranite stone bloc~ in
the parK.
Hitherto wax or any su;table s~nthetic reC ~^. ha^ beeY
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10~8386
1 used for applying on the stone surface to form a transparent
protection coatinp;. This treatment, however, has been found
un~atl~ractory in that not only the coatin~; is readily wiped
~way or the coated film i9 apt to be partly peeled off but also
such coating or film adversely affects on the desired properties
Or marbleQ, graniteQ etc. such as reqpectively- characteri~tic
lu~trous color and sence of touch.
'~he inventor has ~ucceeded in fairly complete protection
of the stone surface by treating ~uch stones of crystal ~rains
and consequently havin~ chin~s or gaps therebetween with a
specific agent in the liquid phase for impregnation which is
then solidiried so as to fill up every cryQtal grain gap open
at the stone surface. Arrangement of the crystal grain~ and
consequently of the gaps are complex and not uniform, but it
can be ~aid that each of saia gaps may not only extend sub-
~tantially vertically so as to be exposed at the ~tone surface
at one end thereof but also be connected with saps substantially
transversely extendin~ at the rear o~ the crystal grains, and
mutually connected gaps ma~3 extend often intG fairly deep inner
portion. ~en a colorin~ a~ent is applied about the time of
applying said filling-up esent, thu~, not only durable but also
natural coloring is attainable.
There have been produced natural ~tones of varlous beautirul
colors and patterns. For instance marbles whicn cGnsi~t al~ost
of crysta] li~e~tone or calcite and fall under the categvr-y
of metamorphite derived from limestone may cGrtain a small
amount of minerals ~uch as carbonaceous subata;~ces, irori oxide,
an~ite or pyroxene, horr.blende, chlorite, clay ard the lii~e
which give the marbles various color~ such as ~reerl, red, purple
and blue as well as patterns. Althoug~ there are pro~luced T~rhite
or grey marbles in large quar.titie_, but cGlored beautif~l
marbleS are hardly obtainable an~ ery expers;-Je. As fGr ~ran1ter,
10!~8386
l these con~ist mainly o~ quarz and feldspar and contain a small ;
amount of minerals such as black and white mica, hornblende
and the like whi¢h impart gives colors Or black, red and blue. ;
Whlte-black granites such as called "Inada-i¢hi" or 1'Inada-
Mikage" and produced in the Kanto Distric of Japan, white-black^
red granites such as called "Mannari-ishi" and produced in the
Chyugoku ~istrict of Japan are common and produced in large
quQntities. However red-bla¢k granites Juch as oalled "~mperial
Red" and blue-black granite~ such as called "B1ue Pearl"~ ar~e
r~re ~d expensive.
The inventor has found it can attaln durable and natural
coloration of marble~, granites and tho li~e stone to apply
a coloring agent in addition to application of said filling-up
ugent in liquid state to be made solld thereafter.
A principal ob~ect o~ the present lnvention i~, thus, to
provide a method for stone surrace treatment which can obviate
and o~srcome the do~ect~ re~erred to abov~.
A particular obJ~ct o~ the invention i~ to provide a
method for protecting the stone ~urface for a considerably
long time without adversely a~ecting on the deslred properties
o~ th~ respective stone such as colors and ~nce of touch.
The other obJect i~ to provide a method for coloring
the stone 3urface durably and in the color tone li~e as
naturally colored stone.
me still other ob~ect is to provide the stone surface
treatment as referred to above to be readily combined with
the conventional stone grinding and polishing treatments.
Various advantage~ and obiects other than the above o~
the invention will be readily appreciated by studyine more
detailed explanation and sxamples of the invention to be given
hereinafter wh-ch ~hall be made not ~or re~tricting it thereto
but merely for making the invention more readily and correctly
1Q98386 ~
',:
1 under~tandable. -~
According to one aspect of the invention, the liquid agent !
with which the mater~al stone i8 impregnated to be ~olidified
later in the cry~tal grain gaps existing at the vicinity of and
opened at the stone surface may be any monomer or lower polymer
to be readily penetratable such gaps and polymerizable when
heating at a fairly low temperature ~o a~ not to adversely affect
on the stone structure and properties to form a transparent, fairly
hard and compact polymer or copolymer. It has been found pref-
erable, however, to use above all styrene monomer and variou~monomers to form ths so-called acrylic resin, among which methyl
acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate,
a-methylcyanoacrylate and a-ethglcyanoacrylate are more preferable.
The lower polymer of the above o~ which polymerization degree i8
le~s than 30~ may al~o be used.
According to another aspect of the invention, said liquid
agent for filling-up gaps i~ a ~olution of paraffin, nitro-
cellulose lacquer, poly~inyl chloride, vinylacetate resin or
the like of which sol~ent is evaporated after impregnation so
that the solidified solute is left in the crgstal grein gaps.
As for the coloring agent, every organic and inorganic
pigment and every dyestuff may be used. Two or more pigments
and/or dyes can be used a~ mixture. They may be di~solved or
dispersed in inorganic solvent such as water and carbon di~ul-
fide; or~anic solvent such as the alcoholic inclu~ive of
methanol, ethanol, the ~etonic inclu~ive of methyli~obutyl-
ketone, butylisobutylketone, the esteric inclusive of
methylacetate, ethylacetate, dibutylphthalate, dioctylphthalate,
and the benzenic inclusive of benzene, toluene. Among the
inor~anic pigments, preferably u~ed are chromimm oxide, Cadmium
~ellow, Chrome Yellow, Pru~sian Blue, Ultramarine Blue and
Cadmium Red. As for the organic pigment~, preferably u~ed are
- 5
1~983~36
1 phthalocyanine, Green ~old, Lithol Red and Hansa 'Yellow. Among .
t'he dye~, there are preferably water soluble direct dyes ~uch as
Dirr.~e~ Yello~r, the Zapon series such as Zapon Red, Zapon Green~
and the Orasol series such as Orasol Red, Orasol ~lue respec-
tively soluble to the above qo]vents. A fillin~-up agent
such as methyl methacrylate itself may be used as solvent for
some colorin~ agent such as Orasol Red.
Impre~nation of the stone with the filling-up agent and/or
the colorin~ a~ent is preferably carried. out by soaking the stone
piece or plate in the bath of said liquld agent or mixture of said
two agr~7nts, although it is posqible by any other mea.ns for instance
by spraying. Applying the filling-up agent and the coloring
agent may be done ~r7parately, in which the latter is preferably
done first.
Example 1
A plate of white marble produce~ in Forrnosa and of 4.G cm
by 20 cm with 10 rnm thlckness of which one si~le surface had
been ~r~round and polished was soaked in the filling-up a~ent
bath consistin~; of methyl methacr~Jlate added with 0.1 mol~
2C benzoyl peroxide as poly~erization initiator at thç room
temperature for 6 hcurs, anr~ then at a tern~eratu-re of oC5 rOr
20 minutes for proceedin~ with prelirninar~ pol~.rnerization. The
stone plate was then taKen out of said 'bath to be i~e~t ;n the
air of 100C for 6 hours7 fo. completing ~ol~.erizatirJrl Or the
fillin~-up agent.
The surface Or the trrated mar'cle Ljlate wa~ ore l~strou~.
than and water repellent in co!~parison ~I tr. ~ne ~treated
similar marble plate a~7 the crjr!tro' The t,.o ~la5e~, one
treated an~ the other untreates, were laid _ -le b~ .eide in
front of the laborator-r office entrarce a.n~ o.p~e~l e~-.S7r-~ ~JaJ
for one mo~th. '~he treatel rQarble piese wa~ a rno.~t sarrle ~itr,
the fresh marble ctone plate but the -~n~reatf~i Grle -~as f'airlJ
"
a83~6
.,~,iled so that said two were clearly distingui shed according
to th~ b'lin(~l p~nel test.
~xr~rn~ le
The marble e,tone ~)late as used ir. :Example 1 was soaked
in the bath of 5 wei~ht~O Ora~cl Rea as the colori.n( agent
di s solved in methyl methacrylate, to which further 20 mol7~
rnethyl acrylate ~las added, for 3C minutes at the room ternpera.-
ture, and then take-n out ther eof to be dried at the surface .
This treatment was repeated ~ times. ~rhe stone plate was then
soaL~ed in said bath to which azobisisobutylnitrile was ad-led
as the pol,ymerization initiator at the room te-,~peratur e for
30 minutes, and then at a temperature of ~GC for 15 minutes.
Ilhe test piece was taken out of thei bath to be xept in the
air of' lGOC for 6 hour~ for completing poly7rlerizat ion of methyl
meth~crylate .
The surface of the treated mar~le etone ~>late ~,ras colored
in vivid and l.ustrou~ red rio less better th~.n tne rlatu.ral.ly
colored marble.
~ample 3
A piece of ~-,rar~ite called "Inada-ishl" pro~ ec~ lrl the
Kanto District, Japan an~ of' 3G c-r. by 30 c~,. bl ~,0 CJn of w'hich
every side was rou~hly grourl(~ waC soaKer3 i rl the bath of'
solution of 5 wei~,ht,~b Orasol Red ln methJl eth~l ,retGrle a~ t'ne
colorirl~- al~er;t to be ~:lfficiently imp-re,gr,ate~J.. ~4f te- ~7ryin~J,
the stone ~iece was eoa~.ed in the 7cath of half-an~l-half
rnixture of st~,rrene and rrlethyl rr.e-thacr,~late ar/~r'e ~,;ith 0.1 mol~O
benzo~l r7eroxide at the roor~ territ,erat7l,~e fc,r ri hours. Ths
graIlite piece was t~en out there~f to be ~e&t irl the alr of
110~ to proceed with copol,-,rmerization o~ s 1i~7 ~.orJorr!erc
30 contalninF the col.orir.,, a ent. O-rie s~ide of~ t,r,e s;,or? r"a-,
sll~htly "rc7~n~l and poli~e'ner~.
The red-blac~ ,-.ra.nlte ~jf li n ~ ter re ~e ~e~ a~, ,bt
1048386
1 to be suitable for the building material.
~xample 4
The ~ranite stone piece as used in Example 3 was soaked
in the bath of the mixture of styrene and acrylonitrile in
: 2 mol ratio added with 0.1% benzoyl peroxide at the room
temperature for 1 hour, and then at a temperature of 80C for
15 minute~ for proceeding with preliminary copolymerization.
The test piece was ta~en out o~ ~aid bath to be kept in the
air of 100C for 6 hours to complete copolymerization.
mere wa~ observed lu~tre and substantially complete
water repellency at the surface in comparison with the untreated
stone piece.
Exam~le 5
The filling-up agent was prepared by dilutin~, Acryl Sirup
which is a trade mark of about 30~0 lower polymer Or acrylic
acid with the ~&me amount of methyl methacrylate. A piece of
gran,ite stone called "Mannari-ishi" produced in the Chyugo~u
District, Japan of 30 cm by 90 cm by 120 cm was put into a
polymerization vessel which was .~ealed and air-evacuated by
means of a vacuum purnp. Into said ves~el was fed said filling-
up agent and filled nitrGgen gas so as to be ~ept at 5 Kk;r/cm2
by gauge pres~ure for ~ hour~ for impregnatini; the st,one piece
with ~aid lig,uid agent. The lia,uid agerlt was tnen excluded ~nd
the stone piece impregnated with the liouid a~ent was heated
in inert atmo~phere at a temperature of 85C for 6 hour~i for
completing copol,ymerizatiorl.
When the stone surrace was sli~htl~J .-Jround ara poli3hed,
the characteristic pattern of sald stone wa~s obser-~ed beautiful
a~ if wetted.
hxample 6
The marble stone plate as used in ~xample 1 ~la.-, .,oa~e~
in the bath of suspension of l wei~Jht~ Cadmil~.m Yello,J in -,~ater
lQ~838~
1 for 1 hour, and then taken out thereo~ to be dried. The stone
plate was soaked in the bath of the lacquer dissolved in the
thinn~r for 30 mlnutes and taXen out thereof to be dried, which
treatment wa~ repeated 4 times.
Thf treated marble plate was tinted in light yellow and
crystal grain ?gaps were completely filled up with the lacf~uer
so that the stone c2urface was lustrous and beautiful no less
better than the naturally 50 colored marble.
~x~mple 7
The marble plate a~ use~ in ~x~mple 1 was soa~ed in the
bath o~ 10 gr. Zapon Fa~t Green di?3solved in 1,000 cc. methanol
for 1 hour and ta~en out to be dried. l'he 3tone plate was
soa~ed in the bath of the lacquer solution in the thinner for
30 minutes which treatment was repeated 3 times.
The treated marble stone was tinted in li~ht green and
?showed beautiful color tone no less better thr~r. the natural
green marble.
~xample 8
The stone plate clit a~ in ~xample 1 but not of marble
but Or "Pocheon Granite" prodljced in ~orea wasl soa~ed in the
bath of 100 ct~r. Ora?2ol ~ed and 30 gr. Orasol ~rown d;s~olved
in 1,000 cc. methanol as the color-in~r age..t at the rtjom
temper~ture for 30 minutes, arl-~ ta~en out frorrl the bath to be
dried, which treatment was repeated 3 times. The yranite stone
plate was so&~ed ir~ the bath of nitrocellJlo e disc,olved in
methyl acetate as the filling-up aC?~ent at t~.e roor?l temperature
for 1 hour and taken out thereof to be dried ~7hitr. treatment
was repeated 3 times.
The granite stone treated a~2 a~o-~re was rJo e-_ better thari
the red granite called Imperial ~e?~ pro?~ute~ wef3en. il?hte
crystal grain C7~aps were -~?el] filled u? ,~ith thC age..t.
5xam~1e '3
lQ~8386
1 The plate Or 3.2 m by 8 m and 5 cm thic~ness of white
marble produced in Formosa was ~round and polished at one
~ide thereo~. It was ;ntended to form a mural painting of
"A~afuji" or "~ed Mount Fuji" by Ukiyoe Artist, Hokusai on
said marble plate. With covering the mountain portion of the
marble plate by means of a plastic material sheet, the solution
of Ora~ol Blue in ~ethanol was applied by 3praying for coloring
the s~y portion. The solution of Orasol Red in the solvent was
similarly applied for coloring the mountain portion and then
the ~olution of Orasol Green was applied at the left lower
portion on the marble plate. The marble plate was then impreg-
nated with the solution of the lacquer in methyl acetate for
filling-up the crystal grain gaps and driecl. The color tone
was not ~o gaudy but placid. Owing to that the coloring agent
was carried by the filling-up agent in e~ery crystal grain gap~,
the colors are to be durable for a long time.
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