CA1088840A - Tile and grout cleaner - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A tile and grout cleaning composition is provided which consists essentially of about 1.5 to 7.0 weight percent of a sequesting agent expressed on a free acid basis; about 1.0 to 3.0 weight percent of an alkaline hydroxide; 1.0 to 4.0 weight percent of 2-heptadecyl-1-carboxymethyl-1-(2-hydroxyethyl)-2-imidazolinium chloride; and the balance is water wherein the composition is capable of existing as a thixotropic gel at room temperature and of forming a water-impermeable outer skin upon application of the composition to the tile or grount surface.

Description

2AC~GRO~D OF T~ '~;~lOII
Many cle~ning products have been developed for cleani~3 cerP~,Ic tile and grout. Specificall~, such cleanlnx in~olves t:~s removal of hard water saLt3, soap scum or curd and gre~sy-t~J~e resi~ues from 6uch surfaces. ~Jpicall~, such products con-t~ ettin~ ~3ents to penetrate the soil) sequesterin~ QgentS for remo~ing hard water salt~ ~nd soap scum and possibly thicXener3 for preventine the running of~ o~ such products when they are applied to vertic~l surfaces. Typical o~ such cleaning compositions are those described in U.S, Patent ~os. 2,371,523 to Xenderson; 2,544,649 to 3ersworth; 3,001,945 to Drew et al; 3,454~500 to L~ncashire; 3,484,373 to Mankowich; 3,870,560 to Shumaker; 3,905,909 to Bauer; 3,g65,04a to Murtaugh; 3,568,o48 to Bolan; 4,020,016 to So~ol ~nd 4,028,261 to Petersen et al.
Although such products perform quite well on ceramic tile surfaces which are relatively non~porous, they do not satisfactoril~
remove stains on grout ~urfaces which are much more porous. In contrast to the a~orementioned prior ~rt, Applicant has surprisingly found that quite effective tile and grout cleaning composition~ can be obtalned for remov~l of the soil and stains a~sociated therewith by pro~iding for a composition which ls capable of existing as a thi~otropic gel Rt room temperature and providing Q water-impermeable outer ~kin u~on application thereof to the tile or grout surface.

'~

, ,~ .. ,.. .. ..... , , , ~

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

:: - .. .. . .. .. . . .. . .. . . .

.: - ~ : ...... . - . : , . . . . . . . , . . . - ~ -SU~1A~ OF Tl~ ~.NVENTIOr~
In accord~nce with Applicant's invention~ a co~position 19 provided for cleanin6 tile Qnd grout which consist~ e~en~ialiy of:
(a) ~rom about 1.5 to 7.0 weisht.percent of a sequestering agent said concentration be.ing expr2ssed on a free acid ba31s;
(b) from about 1.0 to 3.0 weight percent of an alkalino hydroxide selected from the group consisting of the hydroxides of potassium, sodium and ammonium, the amount o~ hydroxide bei~g such a~ to combine with the sequestering agent to form a salt thereof, re~tlng in substant~ally no ~ree hydroxide in the composition;
(c) from about 1~0 to 4.0 weight percent of 2-heptadecyl-l-carboxymethyl-l-(2-hydroxyethyl)-2-imidazolinium chloride; and (d) the bal~nce being water, wherein the composition is capable of exlsting as a thixotropic gel at room temperature and o~ forming a water-impermeable outer skin upon application of the composition to the tile or grout surface.
Optionally~ the composition may additionally i~clude up to about 6.o weight percent of polyethylene gIycol monostearate.. The composition may also contain up to about 0.15 weight percent of sodium lauryl sulfate.
Also,the seques~er~ng agent may be ethylenediaminetetraacetic acid.
. DEIAIL3D DESCRIPTION OF TH3 INVENTION
_ ~ . . , . . _ . .
The no~el compositions o~ the invention for the cleaning o~ ..
tile and grout include a seque~tering agent, an aIkaline hydroxide, 2-heptadecyl-l-caxboxymethyl-l-t2-hydroxyethyl)-2-imidazolinium chloride and water. It is most i~portan~ that the composition be capable of existing as a bhixotropic gel at room temperature and of ~orning a ~ater-impermeable outer skin upon application to the tile or grout . . - 2 -surface. This 1~ neccss~ for thre~ p~poses:
(1) the ~el f(~r~ belng required to keep the compo3itio~
in contact wlth the soiled surface;

(2) the thixotropic property being necessary to allow the composition to be applied or disp~rsed ~rom a pump spraylng applicator, while permitting the product to set up as a semi-rlgid gel u~on applicstio~ to the æoiled surface; and t3) the formation of ~ water-impermeable o~ter ski~
(i.e. "skinning e~fect"~ upon appllcatlon o~ the composition to the surface prevents loss o~ the water content from the ~
composition to the atmosphere, thereby preventing the composition from drying out and losing its cleaning effecti~eness.
Thus, the present tile and grout cleaning composition, in ~ accordance with Applicant's invention, is quite different from and 15 Iql1~ more effectiveit~e~ those previously disclosed in the prior ast in ! .
providin~ for the capability of greater contact time bet~een the c~mposltion and the soiled surface thQn has hereto~ore been obtained.
As ~as previously mentioned, the compositions can be conveniently applied to the tile Qnd grout surface by dispensing from a pump ~pray valve, since the thixotropic behavior allows the compositlon to ~low under the stress applied when the val~e di~penser is actuated.
0~ course, this does n~t mean that the compositian cannot be applled by other means~ such as ~ damp sponge or rag.
~he ~equestering agents which are useful are those agents 2S having the capability o~ chelating or complexing, particularly calcium and magnesium ions which are ~ound in hard water. Thus, typically~ the sequestering agents which are found to be useful are the alkaline hydroxide and ammonium s~ts of alkaline po ~ ne polyca~oxylic aclds and nitrilotriacctic ~cid (i.eO NIA). The alkaline polyamine polycarboxylic acids-generally can be represen~ed by ~he formula:

1~4~
, (~{CCcH2)2rl[ (c~l2)xNcH2cooH]ycH2cooH
whereln x and y may e~ch independently be from 1 to 7.
Representative of some of these salts of amino polycarboxylates especially u~eful in the compositions of this invention are ethylene diaminetetraacetic acid~ N-2-hydroxyethyl-ethylenediaminetetraacetic ac1d~ N-2-hydroxyethyl-nitrilodiacetic acid, ethyl6nediaminetetra~
proprionic acid, and diethyle~etriamine pentaacetic acid. The above described sequester1ng agents can be utilized in the compositions of this invention in all combinations, such as, for example, mlxin~ of nitrilotriacetic acid and an alkylene polyamine polycarboxylic acid.
Generally ~rom about 1.5 to 7.0 weight pe~cent of the sequesterin~-agent is pre~erred, the concentration being based on the free acid (i.e~ not as a salt~. At levels much below 1.5 weight percent, a los~
o~ effectiveness occurs inso~r as the ability of the composition to chelate the magnesium or calcium ions found in hard water stains~
At levels much abo~e 7.0 weight percent, there is a tendency for the gel to lose its stability and break down leading to undesirable phase separation of several ingredients.
The al~aline hydroxides are present in a concentration from sbout 1.0 to 3.0 weight percent and useful for primarily forming a salt o~ the ~forementioned sequestering agents to make them soluble in water.
Stsblc gels ~re obtained provided there is substantially no ~ree exces3 hydroxide in the compo~ition or perhaps only a slight excess tbereo~.
Therefore, the concentration range provided above is most useful with the concentrstions provided for the sequestering agents. Due to their ready availability and price, the alkaline hydroxides of choice ~or use herein may be the hydroxides of potassium, sodium or ammonium.
Amphoteric surfactants ha~ing a quaternary imidazolinium ~ ~tructure have been found to be useful in the cleaning compositlon~
according to the invention, with partlcularly 2-he~tadecyl-1-carboxymethy}-_ 4 _ 8~ 0 1-~2-hydroxyethy1)-2-imid~zolinlum chloride (supplled by the Mlranol as the sodium s~lt Chemical Co., Inc. as a 21 percent solutian of active/cslled Mlranol DM; or by Lonza Chemical Co., Inc. as Amphoterge S) being found to be st preferred because o~ its ability to cause a "skinning effect" when used in the composition. In other words, when the composition is applied to the tile or grout surface, usually vertically inclined, the composition immediately sets on the sur~ace as a thixotropic semi-rigid gel with the outer æurface thereof formlng a thln outer layer or skin which prevents -w~ter from the gel composition from e~aporating into ~he surrounding at~osphere. Thus, the composition may be left in contact with the soiled tile or grout surface for ~ much longer period o~ time (e.g. up to two hours or longer) without lose of cleaning effec~iveness due to the gel drying out, and resulting in much greater cleaning effectiveness than heretofore has been attained.
It has been found useful to use between about 1.0 to 4.0 weight percent of the aforementioned imidazolinium chloride on the pure basis in the compositions of the present invention. At levels much below 1 weight percent, there is a tendency for the gel to become less stable, with Qn attendant loss in the "skinning effect'i in reducing the evaporation rate of water from the gel after Qpplication to a tile surface. Whereas, at levels above 4.0 weight percent, no change in "skinning effect" appears to occur.
At concentrations of the imid~zolinium of about 1.0 to 2.0 weight percent, it has been found preferable to ad~itionally lnclude up ~ to about 6.o ~eight percent of an emNlsifying agent to stabilize the gel and maintain thixotropic properties. A useful emNlsi~yine agent for this purpose has been found to be polyethylene glycol monostearate, which is supplied for example by Glyco Chemical Co. as Pegosperse 400 k~.
Addition~lly, it has been found desirable to incIude foaming agents which can aid in the remo~al of the soap ~cum9 grease and hard 8~) water stains on t~le ~nd grout surf~ces. The ~ddltion of up to about 0.15 weight percen~ of ~uch ~gents have been found to be ef-fective.
Particularly useful are anlonic surfactsnts such as sodium lauryl Slllf'Bte .
Other optlonal additiv~s can be utilized in ~mounts up to about 10.0 weight percent. Included are various surfactants ~or special cleaning purposes such as non-ionics and anionics. Typical o~ the nonionics are ethoxylated octyl and nonyl phenols sold by the Rohm and Ha~5 Co~pa~y a~ their Triton series of surfactants. T~pical of the anionic surfactants which can be included are qodium lauryl ether sulfate. Other optional addit~ves include colorants, perfumes and bactericidal or germicidal agents in minor amounts.
It ls~ of course, preferable that the pH of the resulting g&l composition be above 7 (i.e. alkaline) for gel st&bility and ~aint~nance o~ the sequesterlng agent in the salt form for solubility in the gel.
The cleaning co~position~ in accordance with the present invention, can be made by ~ixing the ingredients in almost any order. However, it is - prefered to separate}y mix the al~aline hydroxide and the sequestering ~gent to obta~n the ~alt form for the sequestering agent prior to mixing with the other ingredients. It is also preferred to initialIy heat the water to approximatel~ 130F and then add the other ingredients thereto to promote rapid dissolution in the water. After such mixing and dissolutlon occurs, the mixture can then be cooled down to approximately 100F, at which point the perfumes and colo~ants may be added as needed. Then the sol~tion may ~e further cooled down to room temperature to allow the thixotropic gel to form.
In debermining the stability o~ the thixotropic gels in the ex~mples that ~ollow, such gels were considered "stable" if they did not sep~rste into mulbiple pha3es and were able to s lntain their semi-rigid gel-like structure under the following conditlon~ after:

~ 4 0 - (1) 2~ dayq at 125~;
(2) 90 days ~t room temperature (i.e. about 68F);

(3) 90 days at 125F; and

(4) a 3 cycle freeze test~ln which one cycle constitut~s ~reezing the compositlon for 24 hours, then lettlng it thaw for 24 hours;and repeating the cycle two more times.
In30~ar as the cle~ning "effectivene~s" of the formulations in the followlng examyles, a 4~point sc~le WBS used: excell~nt, good, falr and poor. If a c~e~nine formulation w~s ~udged fair or poor, la it was not codsidered effective. If the rating was good or excellent, it was considered effecti~e. For rating e~ch of the ~ormulations, two tests were used a3 described below in which 5 t~ 10 people were as~ed to ra~k the formulas according to the previously described rating system by obser~ing the cle~ning results obtained~ us`ing the below described test procedure.
In one test, dirty shower doors were obtained from the home3 o~ several consumers wh~ch had been soiled under normal use. Upon these doors were applied the cleaniDg ~ormulation utllizing a one-inch artlst brush. The cle~nlng ~ormulation was left on the soiled ~ur~ace for at least 10 minu~es, and no greater than 30 min~tes, and the~surface was gently wiped and rlnsed, and the cleQning ef~ectiveness ratings were made based on observation and averaged for a rating either "e~fecti~e"
or "not effective".
The second procedure involved heating a ceramic wall tile to 2S 350F ~n a hot plate, then spraying the entire sur~ace with a 0.2 weight percent solution of FeC ~ in 300 parts per mil}ion hard water ~nd allowing to dry. Then spraylng the entire tile surfac6 heavily with a 0.1 welght percent~solution of~Ivory soap~in 300 parts~per million hard water and ~
~llow to dry. The tile is removed from the hot plate and allowed to cool -3~ to room temperature. With a one-inch artist brush, one-hal~ o~ the tile :
,, , ~8~

i9 coated with the Eormula being tested. AFter leaving the fonnula coatlng on for 10 to 30 minutes~ the tile is gently wiped and rinsed in water.
Cleaning effectiveness ratings are given based on observation. The 300 parts per mlllion hard water was initially preparecl by mixing in 1,000 milliliters of deionized water the following ingredients: 0.2368 grams of CaC12;
0.2104 grams of M~S04 7H20 and 0.2064 grams NaHC03.
To obtain the cleaning effectiveness rating for each formulation in the following examples, a rating indicating "yes" for effective would mean that in both of the aforementioned tests the average rating was at least good or excellent. If either of ~he average ratings for the tests were fair or poor, then the effec-tiveness would be indicated as "no".
In the following examples, unless otherwise indicated, the defini-tions for each of the chemicals referred to in the examples is described below:
Common Name Chemical Name 1. EDTA Ethylenediaminetetraacetic acid 2. EDTA (Na4) Tetrasodium Salt of Ethylenediamineeetraacetic acid 3. EDTA (K4) Tetrapotassium Salt of Ethylenediaminetetraacetic acid 4. EDTA (NH4) Tetraammonium salt of Ethylenediaminetetraacetic acid

5. Versene 100 38% Solution of EDTA (Na4)

6. Equex "S" Sodium Lauryl Sulfate (29% Active)

7. Equex "SP" Sodium Lauryl Sulfate (29% Active)

8. Amphoterge S Substituted Imidazoline (25% Active)

9. Miranol DM 2-Heptadecyl-l-Carboxymethyl~
(2-Hydroxyethyl)-2-Imidazolinium Chloride (20% Active)

10. Pegosperse 400 MS Polyethylene Glycol Monostearate

11. Triton X-100 Octylphenoxy Polyethoxy Ethanol (100% Active)

12. Triton N-101 Nonylphenoxy Polyethoxy Ethanol (100% Active)

13. Sipon-ES Sodium Lauryl Ether Sulfate (27% Active) ~ ~ .

;' ', : ~: . ,. . . - ~ ... . . . ..
.. -- : . .. . . , , ,: . : .:

14. ~TC-2125 Antimlcrob1al ~eent-mixture of ~lkyl Dime-thyl Bsnzyl Ammonium Chloride (50~0 C12, 3Cqo CH14, 17~ C16, 3~0 C18) and AlXyl 5. Dimethyl Ethyl ~enzyl Ammoniu~
Chloride (60~o C14J 3010 C16~
5~ C12, 5% C18) sold b~ the Onyx Chemlcal Company

15. Emcol TS-211 Cationic Sur~actant - Quaternary Ammonium Compound sold by Witco Chemical Corporation

16. Monazoline O Cationic Surfactant - Substituted Imidazoline of Oleic Acid tlO~o Active) Supplied by Mon~ Chemic~ls

17. G~FAC RA_600 Anionic Pho~phate Ester Surf~ctant sold by CAF Corporation

18. ASE 2GO Polymer ~hickener supplied by Rohm and Haas Company .

In the following examples, all percentages are welght 20 . percentages, unless otherwise indicated.

Miranol DM . 5.~ 10.0~ 15. ~ 20.0 . Na4E~IA 3.8 3.8 ~.8 3.8 2 91.2 86.2 81.2 76.2 Added as 10 part~ o~ VERSENE 100, a 3810 Active Solution (Dow Chemical Co.). One gram of e~ch of these formulas were pl~ced on bathroom tile~
and the evapor~tive weight loss determined. ~he results are shown below.
% WEIGHT LOSS
~0 1 2 3 4 .
One Hour ~ 43~ lC~o 7~o ~7~
18 Hours: 92 42 28 30 It;:was concluded that no more than 15~ Miranol DM w~s necessary for weight 106S r~ason3- Formula 3 had acceptable cleaning perform~nce by tile tests and shower d~or test~

_ 9 _ :

.. . ~
.

~8~84~0 EXA~IPLE 5 The followlng composition was prepared.
EDTA (acid) 4.0%
Miranol DM 4.0 Pegosperse 400 MS 3.0 KOH 2.25 Sodium Lauryl Sulfate 0.15 Water 86.6 ~:
This formula had the desired properties with respect to cleaning and thixotropy. :

EDTA acid 1.5 3.0 1.5 0 NaOH 0.4 0.8 0.4 0 Miranol DM lO.l lO.O 15.0 15 H O 88.1 86.2 83.1 85 Tile Cleaning Not Tested Good Good Poor KOH - - 2.25 : :
~2 91.2 81.2 84.75 `
NaOH 0.8 0.8 Miranol DM 5.0 15.0 5.0 :;~
Pegosperse 400 MS - - 4.0 EDTA tacid) 3.0 3.0 4.0 Tile Cleaning Poor Good Good 13 1~ 15 16 17 18 19 ~ 20 :~
H2O (Deionized) 83.080.5 82.5 81.0 79.0 80.5 83.5 81.0 ~ :~
EDTA (H4) 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 KOH (45%) 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 Miranol DM 2.0 4.0 4.0 6.0 8.0 4.0 4.0 6.0 Amphoterge S - - - - - - - -Equex "S" (29%) 0.5 0.5 0.5 - - 0.5 0.5 ":. .

::
: -., :::

: E~LES 1~3 - ? (CO~ ED ) 13 14 15 16 17 18 ~ 20 Pegosperse 400 5.0 5.0 3.0 3.0 3.0 5~0 3~0 3~0 - Triton X-100 0.5 1.0 1.0 1.0 1.0 _ _ 1Ø
Triton N-101 ~ 1.0 - -r Gel Stability yes yes yes yes yes yes ye5 ye~
Cle~ning Ef~ective- yes yes yes yes yes yes yes yes ness E ~
2l 2? 23 : 10 H20 t~eionized) 82.0 82.0 8~.5 ; ED~A (H4) - 4.0 4.0 4.0 KOH (45~) 5. S 0 5 0 Miranol DM 5.0 8.o ~;~ Amphoterge S - 400 Equex "S" (251o) ~ ~ ~5 :~ Pegosperse 400 MS 4,0 1.0 ~3.0 ~ Gel St~bility yes .marginal yes .' Cleaning Effectiveness yes yes yes EXAMP~ES 24 - 31 2l~ 25 26 27 28 2~ 30 31 H20 (Deionized) 85~o 79.5 74,0 73,0 75.075.0 73.5 73.0 EDIA (Na4) 5.0 10.0 EIIA (~t~ 10.0 10.0 ~ E~TA (H4) ~ - - 4.0 4.0 - - 4.0 400 .~
KOH (45~ 7 7.0 - _ _ 7 0 7 5 Miranol DM 10.0 10.0 ~15tO 15.0 1500 - 15.0 15.0 Amphoterge S ~ 15.0 Equex "S" _ o,5 _ _ _ _ _ 0 5 Equex "SP" ~ -5 " ~0 BTC-2125 ~ ^ - 1.0 - - - .
Gel Stability . * * * * * * yes Yes Cleaning Effective- yes yes no no no * yes yes ess * Not.Tested : ~ .

32 33 34 ~5 ~6 37 3~
~0 (Deionized) 72.8 72.8 72.8 72.8 59.o 59.0 63.8 ~OH ~45~o) 7-5 ~-5 7'5 7'5 7~0 7~ 7~0 EDTA (H4) 4. 4- 4~0 4~0 4~0 4~0 4~
Mlranol DM 15.0 15.0 15.0 15.0 500 10.0 10.0 E~col-TS-211 O. 5 0. 5 Equex "S" - _ o,5 o,5 ~ _ _ ~ Sipon ES ~ 2500 ZOOO 15.0 10 ~ Perfume O. 2 0.2 0.2 0.2 ~ - ' Dye - - - 0.001 Gel Stability yes yes no yes yes yes yes Cleaning Effective- yes yes * yesyes .yes yes ness ~S * Not Tested 39_ 40 41 42 H20 (Deionized) 78.8 71.8 79.8 80.8 KO}I (45~) 5.2 5.2 5.2 5.2 ?0 ED~A ~H4) 3- 3. 3. 3.
Mirsnol DM 8.o 15.0 10.0 10.0 . Mlranol C2M-SF 5.0 5.0 2.0 1.0 Gel Stability no no no no ~ Cleaning Effectiveness * * * *
* ~ot Tested , , V

43 44 45 46 47 l~8 ~ . 50 ~0 (Deionized~ al~ 80.0 82.578.5 81.089.5 89~5 GAFAC RA-600 1.5 Monoethanol~mine 4.5 30.0 EDIA (acid) 3~ 20.0 ASE 200 ~10.0 Miranol DM - - 10.010.0 10.010.0 75~ ~ P4 - - 10.0 - 10.0 - 7.5 Citric Acid - - - 7~5 ~ 7~5 ~ 7~5 Monazoline 0 - - - - 1.51.5 200 2.0 BTC-2125 (50~ 1.0L 0 Gel Stability * * * * * * no no Cle~ning Effectiveness no nono no yes no no no * Not Tested EXA2~LES 51 - 57 51_ 52 53 54 55 56 57 ; H20 (Deionized) 85.0 80.0 75.0 70.0 75.0 81.0 82.5 Miranol DM 5.0 10.0 .15.0 20.0 lOoO.10~0 10~0 3 ~0 EDTA (~a4) 10.0 10.0 10.0 10.0 10.0 Triethanolamine ~ 5.0 GAFAC RA_600 - - - - - 1.5 EDTA ~cid) - ~ - - - 3~ 3~
I Monoethanolamine _ _ _ _ ~ 4.5 4.5 Gel Stabllity no yes yes ~ * * *
Cleanin~ E~ectiveness no yes yes noye~ no no .. . .
Not Tested ~`

t 4~
~ IPI.ES 58 - 6?
- 5a 5~ 60 6l 62 H20 (Deionized) 80.0 16.o 85.0 75.0 74.0 Miranol DM 15.0 15.0 15.0 15.0 15.0 3~ ED~A (Na4) 5.0 5.o - lO.o 10.0 t Mo~oeth~nolamine ~ 4.0 - - -5 ~ Sodium Hydroxide - - - - 1.0 Gel Stabllity * * * no no Cleaning Erfecti~eness yes no no yes no * Not Tested h Note that in Example 61~ there was dif~iculty in forming a-¦11 stable gel due to the existence of ~h m~impurities in the 3 ~ solution of EDTA (N84).
* * * * * *

, ,, ', , .

.. . . .

Claims (4)

WHAT IS CLAIMED IS:

1. A composition for cleaning tile and grount consisting essentially of:
(a) from about 1.5 to 7 weight percent of a sequesting agent said concentration being expressed on a free acid basis;
(b) from about 1.0 to 3.0 weight percent of an alkaline hydroxide selected from the group consisting of the hydroxides of potassium, sodium and ammonium, the amount of hydroxide being such as to combine with the sequesting agent to form a salt thereof, resulting in substantially no free hydroxide in the composition;
(c) from about 1.0 to 4.0 weight percent of 2-heptadecyl-1-carboxymethyl-1-1-(2-hydroxyethyl)-2-imidazoliniium chloride; and (d) the balance being water, wherein the composition is capable of existing as a thixotropic gel at room temperature and of forming a water-impereable outer skin upon application of the composition to the tile or grount surface.

2. The composition of Claim 1 additionally including up to about 6 weight percent of polyethylene glycol monostearate.

3. The composition of Claim 1 additionally including up to about 0.15 weight percent of sodium laurly sulfate.

4. The composition of Claim 1 wherein the sequestering agent is ethylenediaminetetraacetic acid.