CA2011351A1 - Hygienic panel of plastic material - Google Patents

Abstract

Abstract of the Disclosure A hygienic panel made of plastic is provided especially for use in a shower enclosure. The panel reliably prevents fungus attack and/or bacterial infestation. The panel includes on at least one exterior side a thin layer containing a disinfectant, particularly a fungicide and/or and antibacterial agent. The plastic of the layer is sufficiently porous that moisture can penetrate into the layer and small amounts of disinfectant agent can carried to the surface during a drying phase.

Description

201~351 ~ac~ground of th~ Inv~ntlon This invention r~latQ~ to a ~anRl made o~ plastic ~or ~e in damp room~, especlally shower enclo8ure6.
Pla~t$c panel~ o~ thl~ klnd are today ~ommonly made by extru~ion methods ~rom 8U~ ta~le thermopla~tlcs and ~erve, a~ do 8h6et~ of ~ cate gla~s, ln room divider~
and the llke for Beparatlng variouD ~paa~s. Such pan~ls o~ thermoplast~cs, having a materlal thiGkness of t~
order o~ mag~tude o~ 5 mm, h~e an inherent st~ff~e6s ~o compar~le or ~llgh~ly lB~a tnan ~hA~ of ~illoate ~lass.
In contrast to pla~tla fllm~ o~ pla~tlc web~, how~ver, lt L9 not po~sible to roll th~m up at room t~mperature, l.e., at ~bout zo C. To ~tlrf~n ~uah panel~, they are ~oun~ed in ~ram~, espeo~ally in ~hower onclo~ures to as6ur~ a 1~ rel~able seal ~rom th~ outs~de, often wlth the uso of ga6kets made of ela3tomer~ Due to lrregularitles in the panel su~ace o~ in th- ga~ket~ or ~a~os, so-called "problem zono~" may be oncountered, lnto which dirt or oth~r forelgr. ~ub tances can p~netrate. Con~d~rabl~ :
~O pro~lem~ may ~ubs~t~uently aris~ wl~h re~pact to hyglen$c requiremente, du0 to microorganl~m~ ~uch a~ ba~t~ria or fungl. EBP~C1a11Y ln aa~p aroa~, sua~ a~ ~now~r room~ ~nd b~throome, th~8 dang~r 1~ ~ubstantlally tn~r~ased d~ t~
th~ ~f~ct~ o~ heat combln~d wlth ~ampn~. Evon th~ t cleaning and c~r~ o~ show~r enclosuro~ ~nd tha ll~e canno~

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20113~1 in pract~co prevent dirt fro~ penetrat~ng and/or fungl an~
~act~ria fro~ ~ettllng in the area of ~oint~ and/o~
Corrl~:L ~ . ~;Ven th~ VC~ . U~
agent~ to co~bat such lnfe~tatlon~ doe~ not lead to 5 la~tlng ~uac~o~, as a rul~, ~lnc4 sven strong cleaning agents act ~or only a ehort ti~e and a~terward hAve to be rlnsed away with cl~an water, ~alling to clean the problem ~on~s completely.
Ger~an pa~ent No. ~E 37 30 820 Al dl~clo~e~ a lo deodorizing and fungu~-co~battlng ~eb or layer of ~inyl chlor~ds r~sln. A dsodor~zing agent and an anti-funga' agent are cont~inod ~n thi~ we~ or lay~r, but they are poorly solu~le or insoluble ln water. ~hls we~ i5 flaxibls and can bQ us~d ln ths mannèr o~ tape~try or wall cov~ring in llvl~g spase ~n the ho~e. Thls w~ treated throughout its thic~nes~ with the agent~ which ar~ poorly ~oluble or in~oluble in wate~ and whlch in some case~ can be ~ppllad wlth an adhe~ve to a text~le material to serve a~ a cover$ng layer.
,o European p~tent No. E~ 304,180 A2 disclose~ a stabillzed antl~icro~lal agent havlng a csrtaln che~ical ~o~posltlon based on a g~ven truotural ~o~mula. ~hl~
agent 1B added to thermopla-tic flber materlals. of ~our~e, ~ib~r materlale and ~br$c6 or the 11~ ~ad~
t~r~fro~ all hav~ a largo sur~aoe ar~a, ~o ~at thQ agènt oontalned ln t~Q flber~ can act on ~h~ mlaroorganl~ms. On the othor hand, co~p~r~tlvely large a~ounts o~ thl6 agent ~re n~ed~, oln~ lt i8 diotrlbuted amonq th~ ~lb~r6 o~r ~helr entlre cros6-sectlonal ~rea..
~0 U.S. pa~ent No. 4,649,07g disolose~ a method by which , ~n ag8nt ~g~ln9t attack by ~roorganl~s can be addsd ~-o ~lb~r~. A partlaular ~truc~ural ~ormula lo glven ~or thi6 ag~nt. Ths flb~r~ manufactured ~y the ~ethod conta~n ~e agent in a lary~ly u~lform dl~trlbution ov~r the cros6 soctlon o~ the f~er~. S~h ~i~sr m~terlal~ ar~ not us~d - 2 ~

- 20113~1 ~ n the pansls ~eecri~ed ~ove. Slnce the agent i5 3ubstantlAlly uni~ormly distr$buted over the aros6-sectional arsa o2 the fib~r~, a large overall amount of ~hi~ agent ~ consu~ed.
Flnally, additivs~ ~or plaetic~ are descrlbed ln the Journal, "Plastver~rbe~t~r," Vol. 28, 1977, No. 5, pages 247-254 whlch g~ve~ a do60rl~tlon o~ the baAic requlremen~ Or and diet~nctlono b~tweon addltive~, such a3 anti-etatlc ag~nt~, dl~ln~octant additivee, blowlng -~
lo agents, etc. With reg~d to d$sln~ctant ~ddltlve~, the articl~ ~tates that it le not tho pla6tlc~, ~uch as ~olyv~nyl chlorid~ ~YC) or polyothylene ~PE), that serve a~ nutriente for the bacteria, b~t speclal additlves such ag ~lller~, plastici2ers, plgm~nt~, ~tablllzers and proce~sin~ aids. In general, the article t~ll3 what ~equirements the dloln~ectant addltlves must eatisty, but ~t ~oe~ not o~fe~ any special tachnloal advlce on how to ~s~t uch reguiroments.

~ummary of ~he Invsn~lgn It 1~ tho ob~at o~ the pre~ent in~sntlon to prov~de a panel of pla6tic wb~ch will ~atl~y hyglenlc .requlre~en~s in damp envir~nm~nte.
It le al~o ~n o~-ct o~ the lnvention 1:o provide a :25 hygienlc plaetic pansl whlch can be rellabl~l and ~economlc~lly manu~acturod.
;Another ob~oct Or tho lnven~ion i~ to provlde a ;:plast~c psnel wh~eh r~ to ac¢umulation Or bactoria and/or r~ngl wl~hout r-qulrlng l~rge Amountl~ ct 30 ~sin$-ctant materl~l. :
A rurth~r ob~ect Or the lnventlon i~ to provide a pla8tlc panel wh~ch malntaln~ the de~irabl~ mAter~a propertie~ of the pla~tlc materlAl ~rom whlch it 15 ~ade~
.T~eoe and oth~r ob~ct~ Or th~ lnv~ntion ar~ ~h$~ved -~
-35 by prov~din~ ~ plastic pan~l for u~ in ar~ ou~ected to 3 - :
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--" 201~ 351 increaaea and deoreaee~ in ambl~nt hu~ldlty, ~aid panel comprlslhg ~ danse core o~ plastlc materlal an~ a porous lay~r of plastl~ ~ate~ial integrally bonded to eal~ cor~
on at l~a~t on~ face o~ eald panel, said po~oU8 layQr having a hygro~coplc antimlcro~lal ag~nt distrlbuted thereln and havLng a ~u~icient poro~lty that wh~n th~
a~blont hum~d~ty lncrease~, moi~ture can ~ig~ate lnto ~Ald 13yer, an~ ~hat when th~ amkl~nt humidlty ~b~eguently decr~aae~, molstur~ will be relea~ed t~o~ sald layor and carry a portton of eald hygro~coplc antimicrobial agent to sal~ p~n-l ~ac~.
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~r~ esarl~tion o~_~he ~rawln~
The lnventlon will ~e deocrl~e~ ln furthRr detal;
1~ with re~erence to the accompanylng drawlngs o~ an illuatrativQ embodim~nt Ln which:
~ lg. l i5 a part~ ctlonal vl~w o~ a plast~c panel accordlng to ~he ~nv~ntion 30unted ~n a ~ra~e member t and F~g. 2 i~ an ~nlar~ed ~ootlonal vl~w o~ a port~on o~
the panel o~ ~lg. 1.

Th~ plastlc panel aocording ~o the inv~ntion avol~
~he ~lsaav2ntages dlscu~sed ~bove and ~atis~les hyglenlc 2s r~qulr~ment6. The panQl contaln~ on at lQas~ one sldo o~ :
a core A thin layer wh~ch con~ain~ an antibact~rial agent an~or di~n~ec~an~ ~nd~or a ~un~cide. ~hls l~yer :-eon~l~t~ ba~ically o~ the ~ame mat~rial a~ ~he ¢ore of the panel, ~o that, esp~ially in ~egard to temperature 3û per~orman~a, nelther manufacturing problem~ nor dif~icultie~ in r~gard to ~tablllty of shap6 wlll re~ult.
~h~ i # ln contras~ to th~ multl-lay~r pan~l~ di~clos~
herato~or~, ln whlch a layer o~ anoth~r ~ntar~al With ~ erent material propsrtiQ~ ha~ b~n diapo~d eith~r ln 3~ rh~ pan~l or on the sur~ace o~ the panel, e~p~c~ally for 2011 3~1 r8in~0rCBment, The core o~ ~he panel and l~kewi~e ~he thln layer have a stlf~ness which correspond~ at least ap~roxl~ately to that o~ s$ltc~te gla~. S~n¢~ ths cor~
a~d the layer con~i~t o~ the Rame materlal, the st~ne~
Or the entire panel 1B not reducoa ~y th~ lay~r 1~8~1f.
This 1~ in ~ontra~ to webs or ~lastic ~ilm~ whlch have a high flexlbllity and wh~n uaed ln ~ sa~dwich construction do not improve the sti~ne~s o~ th~ substrate. Th~ panel in aocord with the inv~ntion ~an th~refore be used in lC ~rame~ $n the ~a~e manne~ a~ conventional panels or, i~
61re~, even w~thout such rrame~, so that a~ far as framQs, hlnge~, ga~k~t~, ~pac$ng from door ~ram~ or th~
are concerned, no de~lgn chang~ have to be m~de, especlally in ~hower enclosur-s.
15In ons advantageou~ embodi~ent, the panel has an smbosse~ texture and/or ind~nt~tlon~ on its sur~ace 80 a~
tC giVB the panel a deslr~d de~lgn~ ~huo, ~trip~d or pebbled text~r~s are provld~d which ~re created ~n thl~
~ thin layer ~fter the production o~ the pan~l with the core : ~0 ant the thln lay~r. It i~ i~portant that the ind~ntation~ .
not b~ do6par than the material thicXn~ o~ the thin outs1d~ layer whl~h contalns t~e antlbac~erlal agent and/or the fungicido. ln ~uch ~trlped, pebbled or bead~d ` texture~ th~r~ 1~ an e~peolally great danger th~t llm~, ; 25 30ap r~lduee o~ even dirt ~ay ~ettl~ in tho~ and that ~icroorgani~m3 or fungl then can ca4l1y ~ain a ~oothold.
Sinc~ the indentation~ how~var, ar~ c~clu~lvely in the : :
outQr layer, ~.e., they do not ~xt~nd all th~ way into the ~or~, ~he ~icroor~an~ n8 th~ ~ungl are killed in them ~0 by the di~infectant ~nd the ~ungiclde in aGGordan~ with the invention . Thc pantl with textur~d ~ur~c~ ~n accordanc~ wl~h ~ne lnvention is th~re~or~ charactarl2ed by a long u~ful 11~ without th~ d~ngsr o~ att~c~ by ~lcroorganism~ ~r fungl. Tha ~GtiVo agont eontaln~d ln ~ 5 ~
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2~1~3~1 the lay~r i8 a dl31n~ectant and/or a ~unglc~de whic~ ~ill6 ~icroorganl~ms an~ h~s a ~l~inrecting actlon.
The dis~n~ectant agent contaln-d in the layer i~
~ygrosaoplc ~nd tne panel $n ~ccordance witb th~ lnv~ntion 1~ used in damp spaces, such AS ~pec~ally ~throom~ and ~hower roo~8. ~he pla~tlo o~ t~ lay~r ha~ an extre~ely ~light, but at the ama time ~u~iclent poro~lty ~o that ln showerlng, ~or ~xample, moi~ture ca~ penetra~e an~ b~
absorbed by the agent. After the ~hower the ~oisture ~0 coht~nt in the shower ~oo~ di~lnish~ snd to establ~ 8h ~quillbrlum th~ mol~ture oontained in the layer alfus~s back out agaln. It 1~ e9paclally import~nt that in th~s -ase tlny ~race~ of th~ a~nt ar~ alBo carried to the sur~ace o~ th~ panel and can the~e perform ~hQlr .5 di~ln~ecting actlon.
~he m~n~mal porosity ot the layer on th~ on~ hand and : ~he hygroscopic action o~ the agent on th~ other ro8ult, ln co~blnatlon, ln an endurlng e~ectivenes~, 6ince the disin~ectant agen~ com~c to th~ ~ur~aae ov8r ~ lon~ perlo~
o~ several years. Thc pan~ u~e~, there~ors, ln damp space~ ln whlch a htgh hu~idi~y i~ no~ perman~ntly pr~snt, but ph~ o~ hlgh humldity are ~ollow~d by dry . pha~ec in which the mol~ture conten~ o~ tha a~bient air 18 sub~tantlally r~duc~d. ~he p~n~l the~e~ore ~ not u~ed in spaces in which a high h~mtd$ty con~tantly prevail~, as ig ~he case, ~or example, ~n are~s o~ p~or ~ir clrculatlo~
or poo~ insulation o~ m~onry ag~n~t mo~u~e. ~ typical location ~or it8 UB~ show~r room or b~throom in wh$ch a high humid~ty 1~ ~st~bl~hed durlng a ~hower over psrlo~ of a hal~-hour or hour, An~ th~n ~or th~ ra~t o~
rhe d~y the humldlty de~ease~ to the level u~ually prevalltng ln rooma ~n th~ ho~Q.
The outer lay~r provided with the disinfsctant, aspscially the germlci~e, and/or ~ ~ung~ctde, 1~ thin in ~5 compari~on wlth thQ total thi~kn~o of the p~nel, A

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2~1~3~1 thlckness "A" o~ the mate~lal rangi~ bBtWOEen 0.15 and 0.4 m~, pref~rably b~tw~en about 0.2 and about 0.3 mm, has p~oven especially er~Qctlve. ~he thlckne~ o~ the lay~r o~ the germic~dal agent ~ange~ fro~ 2% to 15% ~ the total ~hlcknes6 of tho panel, a r~ng~ between 3% and 10% having proven deslrable ln ~ra~t~c~. ~o~t prererably the ~.hlc~ne~ o~ ~he porcu~ laye~ will b~tw~n ~ ~nd 8~ o~ the tetal thic~nes~ of the panel. ~n opti~um i~ Qohi~v~d wlth regard to the longevity an~ e~f~c~lvan~3~ o~ the lo dlsln~e~tant on the one ha~d, and tho ~mount that i5 n~eded in the manuf~cture o~ th~ panel, ~y specifylng the ~aterlal thicXness of tho layer con~aining the dlsin~ectant. ~h~ neaessa~y volumo of dlaln~ectant and fungia1de 1~ k~pt ~all, and li~ewi~e a ~u~iclen~ly larg~
1~ eto~k 1~ produced to cover ~ho ~ntlra expected lire o~ the panel. The total material thicknesq ~" o~ the panel :~
ranges between 2 and 8 mm, e~pe~ially between 3 and 6 m~
the core belng abl~ to OOn~A~ n oolored textures, woven webs and the like, which deter~lne the de8~gn of the whol~
2~ panel.
; The pla~lc o~ th~ lay~r and coro 1~ tran~parent or ~ubstant~ally translucent, 80 th~t the~e toxturea, colors ~tc. will ~e outw~rdly vlsible to the o~server. The thinnes3 o~ the layer a~sures that the lisht tran~mi~ion o~ the thin layer is ~ub~t~ntlally the s~me as t~at o~ the . co~e of the panel. ~hus It i~ pos~ible to u~e even tho5e fungloldes, d$s~n~ectants o~ antibact~lal agent8 w~lCh them~elve~ have a di~orent coloring or together with the pla~tlc chang~ the color ~ect or ~h~ plastic. :~
33 ~he active agont ls oapabl~ of gr~dual~y mlgratlng to : :
*he exterior ~om the layQr an~ beco~l~g ~ective over a long period o~ ~lme of man~ yearB. For u~e ~n damp areas, especially in ~how~r enolo~ure~, lt 18 e~peclally ~eslrable to prov~de comb$natio~ of p~aotlc ~nd ~5 disln~ctan~ ~d fun~iclde which a~orb molstur~ un~r the .`
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20113~1 ac~lon o~ humidlty lntensL~$~d by heat, and thus ~ecome Aygroscopically e~ectlve to ~ c~taln, prc~rably slight, ~xt~nt. When ~u~ec~e~ ~o water vapor ~uring ~howQrlng, th~ pla~tlc panel ab~o~b~ mol~t~re, namely in ~t~ porou~
outer lay~r. Durlng a ~ub~equ~n~ ~rylng ph~Q thLs ~018ture ls ral~a~Qd agaln by the pla~tic p~n~l, wh~le ~t the same time the fungl~de ~n~/or the ant$baotsrlal agen~
i3 brought to ~hc aurfaa~ ln ~ln$~al amoun~ an~ can there produce thelr etSect.
In contraBt to so-oalled protoctive ~11mB which can ~e applied temporar~ly to the sur~ac~ of a panol, th~ th~n iayer providQd 1n aaoor~anc~ with the lnventlon ~nter~
into a unlform bon~ wlth the oore o~ the pan~l. The thin layer cons~sts of the ~a~e plastic a the cor~ and ~ ~ade Lnto an lntegrally bonded unit and panel, s~peclally ~y : coex~ru3ion si~ultaneou~ly wlth th~ oore. T~e : . .
:, ~ntiba~t~rial ~gen~ 1~ ~lxed be~o~e ~xtru~ion w~th a ::
portion o~ the pla~tic that later wLll ~orm tho out~r layer and will b~ bon~ tlghtly and permAnently to tha ~o core. There is a ~r3n~1tion zon~ betwa~n the core ~nd ~h~
~hln layer in which the concentratlon o~ tha dl~inf~ctan~ ~
dl~n~he6. ~ :
I~ th~ ~urfac~ o~ the panel i~ provided with a : ~exture to ach~¢ve a ~pec~al de~gn, ~he d~pest polnt~ ~n Z5 t~ls textured su~ace extend, ln accordance wlth this - lnvQntlon~ all the way to thl~ trans~tlon zone. However, th~s~ indentation8 do not extend lnto the core o~ the pAnel, 60 a~ to prev~nt bacter~a or fung~ ~rom e6~abllshlng them~el~ ln ths~e ln~sntatlons on account or lime or dirt that ~ettlQ thQreln and reslsting ; de~truction because of ~he ~xoe~sl~ely low concentration o~ th~ dis~ n~ectant. ~he comparative thlnne~ o~ th~
out~r l~y~r assures, furthermore, that the l~ght tranomlselon or color e~f wt Or ~he panel wlll not : 35 advsr~ly a~ec~ed ~y ~he di3in~ectant or fungicld~.

20113~1 The panel 1B pr~f~rahly made by ~n extru~lon proa~s~, ln wh~ ch te~perature~ 1~ the range o~ Z00 ~ predominate.
Ther~for~, wlth~n the ~cope o~ the lnvent~on, only tho~e ~ungicldes an~ Anti~t~rlal ag~nts a~e u~ed wh~ch are 5 heat-reslstant Up to 200 ~ ~n~ pre~erably at hlgher t~mper~tur~s ranging up ~o a~out 250 CC. ~hl~ ~sures that ~he che~lo~l compound~ and hen~e the e~ectiv~n~s~ w~ll not be adveraely a~ecte~. Furthermor-, th~ ran~e o~
poss1ble dis~n~sctant~ ~nd ~ungi¢i~e~ 13 consia~rably o ilmlte~ by this selectl~n, but on the other hand i~
~s6ure6 that th~ colorlng and the e~rall che~lcal parformAnce wlll rsma$n unaltered or only mlnimally alterQ~, whllo manufactur~n~ ~an ne~artheles~ bo perto~med ~-w~th conventio~al equlp~ent. ~
A~ mentlon~d ab~ve, the plate o~ the invent~on i~ ~ :
advantag~ously ~or~ed o~ tran~par~nt or tran~lucent plastlc matsrial. ~ranslucsnt acrylate panol~ de~irably ~ay be used. It ls partl¢ularly prs~erred to UB9 a tran~lucent polymethylmethaarylat~ plastlo mat~rlal ~er ~oth t~e aore a~d the porous laye~.
The poroue layer ~ust be su~flclently poreu~ tha~
mol~ture can mlgrate lnto tho lay~r w~n th~ ambi~nt ~.
hum~alty lncr~a~os. The water upta~e aftRr 2~ hour~ at a ~mp~ra~ure o~ 20 C de~lra~ly ~ay range ~om about 0.2 to 2~ 0.5 w~lght-porcent. In one advanta~eous embo~$m~nt, the water vapor permeablllty ie approxl~ately 40 x 10 gram~
p~r o~ntlmeter per hour per Tor~ at a temperature ~rom 20 to 2S C and a ~elative humidity o~ up to 6S ~. At a te~e~ature Or 40 C and a relatl~ hu~l~lty of 90%, th~
w~ter vapor perme~bllity amount~ to abou~ 110 gram~ pex centimeter per hour per Torr.
Tbe sur~ce lay~r ~ay b~ renderod porou~ ~urlng produotlon by extru~lon by sub~ct~ng th~ ~x~ruded layer to a rapld tamperature d~crea~e in order to ~uench i~
35 during or ~r~r rollln~. ~h~ ~xtrud~d w~, whlch : ;~ .: .
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O~l~ 3~1 -comprlse3 th~ oo~xtrud~a cor~ ana porous layer, ~
dvanta~aou~1y pa~s~a whll~ ~tlll ln ~ pl~stlc ~ate ~hrough a roller arrange~ent oo~rl~lng at l~a~t thr~e.
cylindrical roll~rs to smooth the sur~ace and produce _ layar~ of unlfor~ thio~nes~ de~i~ed, ono o~ the~
rollers ~ay be provided with an embos~ng ~ur~ce to ~rodl-c~ ind~ntatlon~ ana/or r~ portion~ on the sur~ac~
o~ th~ pAnel to provlde a textured ~urface wlth a pleasing - app~arance.
'0 E~ther tha a~orementioned embossin~ ~oller or subseguent roller i8 3upplled wlth eoollng water, or a coollng ~an 1~ arranged to ~low cool alr on the extru~ed laye~ downstream o~ thQ roll~r~, to thereby produc~ the de~lr~d poroslty ln ~h~ lay-r through rA~id cooling. ~he lS ~emperature oS the cooling water or alr des~ra~ly w~ll lie ln the ran~e ~ro~ about 20 to abo~t 60 C in order to produce th~ desired rap~d cool~ng. ~h~ poros~y can be r~gulat~d by aa~ustlng th~ ¢oollng ln order ~o adapt the ~olsture uptake o~ the panel to the properties of any o~
~c variou~ commercially avall~ble ~un~lcidG~ and/or ant$-~a~erlal ag~n~ whlch may be us~d ln the pan~l of th~
in~ntlon.
- Re~erring now to th~ draw~ng~, Fig. 1 show~ a portion of a panel 2 accord$ng to the pre~ent ~nvention comprising : 25 a ¢o~o layer 4 and a porou~ layer 8 lntegrally bon~d to : one ~ace o~ the core. Panel 2 l~ 6hown reca1vod in a ~nown manner in a po~tlon of ~ fram~ ~omb~r 10 of a shower door or the ltX~. ~YP1CA1 di~onsion~ Or su~h a panel are ~.7 m~ters hlgh ~y 0.9 ~eter w~de by 4 ~m th~ck.
Flg. 2 iB ~n ~nlarged, seot~o~l view o~ a port~on o~
the panal 2 of Flg. 1. A hy~ro w oplc anti~lcrobial agent ~s represented ~y partiole~ 8 di~tributed wlthin th~
porou~ layer C. Fig~ 2 al~o illu~ate~ lndon~atlon~
~nd ral~sd portion~ 14 provided to ~orm a t~xtur~d ourfac~
3S on the expo~d ~c~ of l~yer G. ~he ~ndent~tlon~ 12 h~ve ;.~} .
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^~ 20113al depth whlch 1~ not gre~ter th~n the thic~nes~ of poroue layer ~. The antlmlcrobl~ agent ~ i8 ~ub~tantially unl~ormly distrlbuted throughout the porou~ layer 6. A
transitl~n zone 16, whl~h conta~n~ a decre~3ing gra~lent s o~ anti~crobl~l agent, i~ ~or~ed at thOE lnter~ace b~tw~n porou~ layer 6 ~nd core 4.
The ~oregoin~ de~c~lption and example~ ha~Q besn set - forth ~orsly to illu~trata th~ Lnvention 3nd are no~
lntende~ ~o ~ limltin~. Sln¢~ mo~lflcation~ o~ the }o de~crlbed embodlmen~e lncorpo~Atlng th~ ~plrl~ and : ~ub~tance of ths inventlon may ocour ~o per~one ~ d in the art, the ~cop~ o~ the 1nvent~on ~hould be ~on~rue~ to lnclude all modi~ica~lons ~ ng wlthln the ambit o~ the appended claims and equivalents thereo~.

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Claims (19)

1. A plastic panel for use in areas subjected to increases and decreases in ambient humidity, said panel comprising a dense core of plastic material and a porous layer of plastic material integrally bonded to said core on at least one face of said panel, said porous layer having a hygroscopic antimicrobial agent distributed therein and having a sufficient porosity that when the ambient humidity increases, moisture can migrate into said layer, and that when the ambient humidity subsequently decreases, moisture will be released from said layer and carry a portion of said hygroscopic antimicrobial agent to said panel face.

2. A panel according to Claim 1, wherein said porous layer is formed of the same plastic material as said core.

3. A panel according to Claim 2, wherein said antimicrobial agent is dispersed in plastic material from which said porous layer is to be formed, and the plastic material containing dispersed antimicrobial agent is subsequently extruded as a porous layer onto said core.

4. A panel according to Claim 1, wherein said porous layer has a thickness in the range from about 0,15 mm to about 0.4 mm.

5. A panel according to Claim 4, wherein said porous layer has a thickness in the range from about 0.2 mm to about 0.3 mm.

6. A panel according to Claim 1, wherein said porous layer has a thickness which comprises from about 2% to about 15% of the total thickness of said panel.

7. A panel according to Claim 6, wherein said porous layer has a thickness which comprises from about 3% to about 10% of the total thickness of said panel.

8. A panel according to Claim 7, wherein said porous layer has a thickness which comprises from about 4% to about 8% of the thickness of said panel.

9. A panel according to Claim 1, wherein said panel comprises two porous, antimicrobial agent-containing plastic material layers integrally bonded to opposite faces of said core.

10. A panel according to Claim 1, wherein said antimicrobial agent is substantially uniformly distributed throughout said porous layer, and a transition zone containing a decreasing gradient of antimicrobial agent is formed ant an interface where said porous layer is integrally bonded to said core.

11. A panel according to Claim 1, wherein said antimicrobial agent is hydroscopic.

12. A panel according to Claim 11, wherein said antimicrobial agent is partially water-soluble.

13. A panel according to Claim 1, wherein said antimicrobial agent is thermally stable to a temperature of at least about 200 °C.

14. A panel according to Claim 13, wherein said antimicrobial agent is thermally stable up to about 250 °C.

15. A panel according to Claim 1, wherein said at least one face of said panel is provided with indentations to form a textured surface; said indentations having a depth which is at most equal to the thickness of said porous layer plus said transition zone.

16. A panel according to Claim 15, wherein said at least one face is provided with a combination of indentations and raised portions to form a textured surface; said indentations having a depth which is at most equal to the thickness of said porous layer.

17. A panel according to Claim 1, wherein said antimicrobial agent is a fungicide.

18. A panel according to Claim 1, wherein said antimicrobial agent is an antibacterial agent.

19. A shower enclosure comprising a frame and at least one panel according to Claim 1, mounted in said frame.