Note: Descriptions are shown in the official language in which they were submitted.
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8Z44
This invention relates to novel coDnposition~ u~eful a~
mortar ~or the in~tallation o~ cer~mic wall and floor tile80
More specifically, it relates t:o such a oomposition contain~
lng a novel water-retention agent.
Conven'cional ceram~ c tile cemen~ are mixtures oP
aement, sand, and thickener. U~ually, they al~c~ eontain
small amounts of polyacrylamide and polyvinyl alcohol to
lmprove performance~ ~he dry cement mixture is then mixed
with w~lcer to ~orm a mor tar .
lû . The physicsal ~haracteri~tic~ of a cured conYentional
mortar a~e de~rmined by th~ rate o auring, an~ thus, ~y the
. rate of water removal therefrom during the curing op~ration.
!. ~ny influence which afects these parameter~ by increaæing
i the ra~e o water removal or by dimin~shing the water con~Qn-
tration in the mortar at the onset o~ the curing reac~ion can
cause a deterioration of the phys~ca~ properties of the
i ~ mortir. Most ceramic wall tiles, on their un~la~ed surfaaes,
I ~are highly porou~ and, when ~et on su~h a mortarr ab~orb~
water there~rom, leading to the di~f~cultie~ ~u~ men~ioned.
~0 Likewise, most ~trata to whiah these tiles are applied ~uch
as wallboard, cinderblock, or masonr~, are also porous and
lead to the ~ame problems.
To overcome, or at lea~ minimize, the ~bove-men~ioned
water-loss problems, it has been ~ugges~ed to ~dd to the
25 mortar compo~itions a ~m~ll a~ount o~ a water-~o~uble pol~- i
mer, ~uch as, methylcellulose ~U~S. Pat~ No. 2,934~932)~ ~
hydroxyethylcellulo3e (U~S. Pat~ No. 3,~43,307)~ or phenyl
hydroxyethylGellulose, benzyl hydroXyethyl~ellulos~ or ethyl
hydroxyethylcellulose (U.S. Pat. ~o.l4,065,31g~ a~ a water
:~LZ~8;24'~
retention aid. These polymers prevent escape of the water from
the cement by increasing the viscosity of the water phase, thus,
maintaining the desired water concentration in the mortar during
curing.
In accordance with this invention, it has been found
that a dry mortar-forming composition comprising, by weight,
from about 24% to about 99.4% of hydraulic cement, from about
0% to about 75% sand, and from about 0.3% to about 4% of a
water-retaining thickener, which dry composition is capable,
when mixed with from about 25% to about 40% of its own weight
of water, of producing a mortar which can be applied in thin
layers for setting tile on walls and ceilings, is improved by
using a modified hydroxyethylcellulose having a hydroxyethyl
substitution from about 0.3 to about 4.0 M.S. and a hydroxy-
propyl substitution greater than 0.35 M.5. as the water-
retention aid or thickener. More than 0.35 hydroxypropyl M.S.
is required to lower the set time of the mortar to the desired
level. Preferably the hydroxypropyl substitution is greater
than 0.6 M.S. Most preferably, the hydroxyethyl M.S. will be
from about 0.8 to 1.8, and the hydroxypropyl M.S. will be from
about 0.8 to about 1.5.
The designation M.S. refers to the average number of
moles of hydroxyethyl or hydroxypropyl substituent groups
combined per cellulosic anhydroglucose unit.
Typically from about 0.3% to about 4% of the modified
hydroxyethylcellulose or of blends thereof is used.
When compared with the mortars prepared with conven-
tional hydroxyethylcelluloses as the water-retention agent,
the mortars of this invention are improved in texture, set
times, and adjustability times, which are three important
parameters used widely in the art to characterize tile mortars.
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a2~4~
They also show improvement in tack and cohesiveness.
Set time is defined in ASTM C266-65. Basically set
time is the time the mortar takes to set or harden at a given
thickness. Adjustability time is the time during which the
position of the tile on the wall can be changed without the
tile coming loose from the mortar.
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84. 1/27 07: 21 P03 ~I~HERC MSG CTR
12Q~ 4
; ~he modiied hydroxyethylcellulose which can be u~ed as
thickener in the mortars of this invention i8 ~r~pared by
reacting ethylene oxide ~nd propylene oxide wi~h ce~lulo~e in
: a stron~ly alkaline medium. SpecifiG techniques ~or Garrying
5 out the eth~rification are well known in the art and any
known procedure c~n be employed.
In ~he alternative, a hydroxye~hyloellulose a~n b~
e~heri~i~d w~th a propylene oxida in ~ strongly alkaline
medium. In this case, ~he hydroxyethylcellulose can b~ sub-
10 stantially any grade having M.S. ~rom abou~ 0.3 to about
4.0O ~he pre~erred materlal~ are tho~e ha~ng a vi~cosit~
from about 800 to about 5000 centipoi3e ln a 1% water ~olu-
j t70n. Materials of higher and lower vi~co~ity ~an also be
us2d advantageously, howe~er.
A tile morta~ ba~ed on Portland cement or oth~r hydrau-
lic cement~ oan ~e pr~pared ~ontaining ~nly the hydraul~o l
cement and the water r~tention aid o~ the instant lnv~ntl~n.
Normally, however ! most ormulatîons will in~lude a rather
~ubstantial amount o~ æand.
The amount o~ hydraulic cement ~an be a hl~h as 9g.4% in
the aase of a mortar containing only h~draulia ~ement and the
modified hydroxyethylcellulo~e to as li~tle a~ ~bout 24~ o~
,j the hydraulic cement in the ca~e o~ mor~ar~ containing sand
; and other component~. Sand, i~ used, should be pr~ent in
the amount of rom vne to three volumes o~ ~and p~r volume o~
hydraulic cement. ~or sett~ng porous tiles, a mixture con-
taining equal volumes o~ hydraulic cemen~ and ~an~ up to one
volume ~ hydr~ulic cement per 1 1/2 volume~ o~ sand produces
a mortar which i~ entirely sati~faatoryJ
~he dry mortae compo~ition may also contain ~inely
I . di~ided inorganic or or~ani~ fibers, 3uch ~s, go~ ~xa~ple,
! ~ mineral wool, glass ~i~ers, ~ibr~us (low sub~ti~ution or.
crossl~nked) carboxy~e~hylcellulose, and the like, in amount
of from abou~ to abou~ 2%o ~he incorporatlon o~ ~he
~ibers improves the thixotropic prop~rties o~ th~ mor~ar,
., the use of fibers pre~ents sag o~ the m~ . U~ing
mortar contalning fibers to bond ceramic tile to a ~ertical
wall lessens the tend~nc~ o~ the tile to ~ down the wa~l
.
84. l/27 07: 21 P04 :k HERC MSG CTR
)8~4
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during setting o$ the ~ort~r. More commonly, ~ 11 amount
of polyacrylamide or o~ an anionic or c~ ioni~ aopolymer o~
acrylamide, i.e., about 1~ ba~ed by weight on the thiakener~
is used to improve sag resis~ance. Polyvlnyl al~hol in
small amount r from about 0.~5% to about 2%, based on the
weight o the hydraulic cement ~ is frequently included to
increas~ wet adhesi~n ~nd ~ttain ~e~ter workability.
~hus~ the hydraulic cement dry m~xture of thl~ invention
aonsi~t~ essentially of from about 24% 'co about 99~4%
10 hydraulio c~ment; from al~out 0.3~s to about 4~ ~ th~ modified
hydroxyethylcellulo~e vr of blends ~hereof,o and ~rom about.O~
to ~bo~t 75~ sand.
~ his dry miXture, when add~d to water~ forma a th~n-set
~ortar~ iOe~, a mortar ~hich ~an be used in ~h~n la~er~ on
the order of 1/8 to 1~4 inch. The amoun~ o~ wat~r ~ea iB
su~h that the resultant mixture will not be ~o ~hin a~ to
~lide down a wall or drop of~ a ce~ling ~hen appli~d! In
gene~al, ~rom about ~5:'6 to about ~0% water, ~y weight based
on the ~eight of the ~ry nnixture~ g~ves goo~ re~ul'cs.
ZO In the examples whiah followt var~ou6 embodlments ~ th~
mortar composition~ of this invention are lllustrated~ In
Exa~ples 1 through 11, the ~ormulation ~hown in ~able I i~
employed excep~ t~at a hydroxypropylhydroxyeShylcellulo~e
having the hydroxye~hyl M.S. and the hy~roxylpropyl M~S.
shown in Table II for ~he particular ~xample in ~ tlon i5
used as the thickener.
Table I
. .
Com~nents _ Part~ b~ we~ht
White Portland ~ement 48.8
30 Fine ~and 50.3
Polyacrylamide 0~0~ ~
Thickener 0~6
Polyvinyl alaohol ~.2
Water ~6.0*
The mortar composition~ of thi~ invention are pr~pared by dry
mixin~ the first ~ive component~ o Table I to a ~ubstan-
tially homo~eneous 6tate, adding th~ dry mtx to th~ water,
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84. l/2~ 07: 21 P05 >I~HER~ lSG GT~
12~8Z~
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and m~nually s~irring to obtain a trowelable mlx with
comple~e and vi~ually uni~orm wetting of ~che dry componente.
The wet mass is slaked or 30 minutes (except for ~hat
portion to be used in ~he set ~ime te~t which i8 ~laked for
5 onl~!r 10 minutesj ~ then remixed thoroughly before ~ny evalu-
ation~ are carried out.
~ por~ion o~ the mortar i~ troweled onto the vertical,
surface o~ a dry cinderblock between ~uide strip~ l/4 inch
thick. A Type B ~floor~ ceramlc tile i~ lightl5~ tapp~ onto
10 the mor~ar surface immedia~ely a~ter Application to the
cinderblock with the back r1bs of the ~iles in vartl~:al .
alignment,. The po~i~ion o the top edg~ o~ ~he tile i~
marked~ Sag is the downward displacement of the tile
measuxed 2 hours af~er placement on th~ mortar ~urac~0
lS Ater ano~her hour o~ slaking the mortar i~ trow~le~ a~
room temperature and about 50% relativ~ humidity (P~Ho) ont~
, a ~e tion of gypsum wallboard and 10 Type ~ ~wall~ ceramic
tile~ are pr2s~ed onto ~h~ mor tar leaving 1/1~ ~ n ::h spa~ing
be~ween the tile~ and wallb~ard. At 5-m$nute in~er~als at
20 room temperature, a tile i5 twisted thr~ugh a 90 angle back
to its original position. P.djustability tim~ i~ the lon~3est
time at which a tile remains affixed to the mortar wh~n
~ce~ted in th i~ manner . The ~haracter i~tics o~ the aement ar~
shown in Table I~ .
~5 Set time i9 the time mortar appli~d to a ceraml~ tll~ at
;~ ~ giver~ thickne~s takes to set or harden a~ measured by
~;ilmore needle according to the procedures o~ A8TM C~66-650 ~ . .
Con~istancy, taak, and ~ohesiveness are 3ubjactiva te~ts
which measure trowelabillty, how well the morta~ ~tlck~ to ~ ;
30 metal spatula or trowel, and the overall ~nte~rity o~ the
mortar aompo~ltio~, ~e~pec~ively.
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84. ` l/27 07: 21 P06 ~HER~ MSG l::TR
8244
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In Example~ 12 through 15 ~he fornnulat,ion s~ ~able I i.8
u~ed except that blends o~ hydroxypropyîhydro.xy~hylcellu~
lo~e~ havln~ the hydroxypropyl and 'che hydroxy¢thyl ~.S.
~hown ;ln Ta~le I~I are u~ed. The prop~rties o the
S comlposition~ of Examples 12 through lS are al~o ~hown in
~able III
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~ eatures, advan'cages and o~her ~pe~lfia embodlments o~
~his inventio~ will become read~ ly apparen~ to tho~e ~xer-
cising ordinary skill in the art after readlng th~ ~orogo~ng
di~clo~ure~30 In this regard, while specific embo~iment~ o~
S this in~n~ion have been descr ibed ln considera~le det~
variation~ and modification~ ~f thes~ embodimen~ can be
effe~:'ced wi~hout d¢p~rtlng ~rom th~ 8pi~ri1: and ~cop~ of the
invention as dis&l~sed and cl~ime~
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