Cellulose Ether

Cellulose etheramapangidwa kuchokera mapadi kudzera anachita etherification wa mmodzi kapena angapo etherification wothandizira ndi youma akupera. Malingana ndi mitundu yosiyanasiyana ya mankhwala a ether substituents, ma cellulose ethers amatha kugawidwa mu anionic, cationic ndi nonionic ethers. Ma Ionic cellulose ethers makamaka amaphatikizapo carboxymethyl cellulose ether (CMC); non-ionic cellulose ethers makamaka amaphatikizapo methyl cellulose ether (MC), hydroxypropyl methyl cellulose ether (HPMC) ndi hydroxyethyl cellulose ether. Chlorine ether (HC) ndi zina zotero. Ma ether osagwirizana ndi ma ether amagawidwa kukhala ma ether osungunuka m'madzi ndi ma ethers osungunuka m'madzi, ndipo ma ether osasungunuka m'madzi amadzimadzi amagwiritsidwa ntchito makamaka muzinthu zamatope. Pamaso pa ayoni calcium, ionic cellulose ether ndi wosakhazikika, choncho kawirikawiri amagwiritsidwa ntchito mu matope owuma osakaniza mankhwala ntchito simenti, slaked laimu, etc. monga simenti zipangizo. Nonionic madzi sungunuka cellulose ethers amagwiritsidwa ntchito kwambiri m'mafakitale opangira zida zomangira chifukwa chakukhazikika kwawo ndikusunga madzi.
 
1. Chemical katundu wa cellulose ethers
Etha ya cellulose iliyonse imakhala ndi kapangidwe ka cellulose - kapangidwe ka anhydroglucose. Popanga cellulose ether, ulusi wa cellulose umayamba kutenthedwa mu njira ya alkaline, kenako umathandizidwa ndi etherifying agent. The fibrous reaction mankhwala amayeretsedwa ndi pulverized kupanga yunifolomu ufa ndi ena fineness.
 
Popanga MC, methyl chloride yokha imagwiritsidwa ntchito ngati etherification agent; kuwonjezera pa methyl chloride, propylene oxide imagwiritsidwanso ntchito kupeza magulu a hydroxypropyl popanga HPMC. Ma cellulose ethers osiyanasiyana amakhala ndi ma methyl ndi hydroxypropyl substitution ratios, omwe amakhudza kuyanjana kwa organic ndi kutentha kwa kutentha kwa ma cellulose ether.
 
2. Zochitika Zogwiritsira Ntchito Cellulose Ether
Ma cellulose ether ndi polima osapangidwa ndi ionic semisynthetic, omwe amasungunuka m'madzi komanso osungunuka. Zili ndi zotsatira zosiyana m'mafakitale osiyanasiyana. Mwachitsanzo, muzinthu zomangira mankhwala, zimakhala ndi zotsatirazi:
①Wosunga madzi ②Thickener ③Leveling katundu ④Katundu wopanga mafilimu ⑤Binder
Mu polyvinyl kolorayidi makampani, ndi emulsifier ndi dispersant; mu makampani opanga mankhwala, ndi binder ndi pang'onopang'ono ndi kulamulidwa kumasulidwa chimango zakuthupi, etc. Chifukwa mapadi ali ndi zotsatira zosiyanasiyana zophatikizana, ntchito yake Munda ndi wochuluka kwambiri. Zotsatirazi zikuyang'ana pa ntchito ndi ntchito ya cellulose ether mu zipangizo zosiyanasiyana zomangira.
 
(1) Mu utoto wa latex:
Mu makampani lalabala utoto kusankha hydroxyethyl mapadi, mfundo wamba wofanana mamasukidwe akayendedwe kukhuthala ndi RT30000-50000cps, lolingana ndi mfundo za HBR250, ndi buku mlingo zambiri za 1.5 ‰ -2 ‰. Ntchito yaikulu ya hydroxyethyl mu utoto wa latex ndi kukhuthala, kuteteza gelation ya pigment, kuthandizira kubalalika kwa pigment, kukhazikika kwa latex, ndikuwonjezera kukhuthala kwa zigawo, zomwe zimathandiza kuti ntchito yomangayo ikhale yolimba: Hydroxyethyl cellulose ndiyosavuta kugwiritsa ntchito. Ikhoza kusungunuka m'madzi ozizira ndi madzi otentha, ndipo sichikhudzidwa ndi pH mtengo. Itha kugwiritsidwa ntchito ndi mtendere wamumtima pamene mtengo wa PI uli pakati pa 2 ndi 12. Njira zogwiritsira ntchito ndi izi: I. Mwachindunji Kuwonjezera pakupanga: Kwa njirayi, mtundu wochedwa wa hydroxyethyl uyenera kusankhidwa, ndi hydroxyethyl cellulose ndi nthawi yosungunuka yopitilira mphindi 30 imagwiritsidwa ntchito. Masitepe ake ndi awa: ① Ikani mu chidebe chokhala ndi chometa chometa kwambiri. Kuchuluka kwa madzi oyera ②Yambani kugwedeza mosalekeza pa liwiro lotsika, ndipo nthawi yomweyo onjezerani hydroxyethyl mu yankho mofanana ③Pitirizani kugwedeza mpaka zida zonse za granular zinyowetsedwa ④Onjezani zowonjezera zina ndi zina zamchere, ndi zina zotero. , kenaka yikani zigawo zina mu ndondomekoyi, ndikupera mpaka mankhwala omalizidwa. Ⅱ. Zokhala ndi chakumwa cha mayi kuti mudzagwiritse ntchito m'tsogolo: Njirayi imatha kusankha cellulose pompopompo, yomwe imakhala ndi anti-mildew effect. Ubwino wa njirayi ndikuti umakhala ndi kusinthasintha kwakukulu ndipo ukhoza kuwonjezeredwa mwachindunji ku utoto wa latex. Njira yokonzekera ndi yofanana ndi masitepe ①-④. Ⅲ. Konzani phala kuti mudzagwiritse ntchito mtsogolo: Popeza zosungunulira za organic ndi zosungunulira zosasungunuka (zosasungunuka) za hydroxyethyl, zosungunulirazi zitha kugwiritsidwa ntchito pokonza phala. Zosungunulira zomwe zimagwiritsidwa ntchito kwambiri ndi zamadzimadzi zomwe zimapangidwa ndi utoto wa latex, monga ethylene glycol, propylene glycol, ndi opanga mafilimu (monga diethylene glycol butyl acetate). Phala la hydroxyethyl cellulose likhoza kuwonjezeredwa mwachindunji ku utoto. Pitirizani kusonkhezera mpaka kusungunuka kwathunthu.
 
(2) Pakhoma scraping putty:
Pakali pano, m'mizinda yambiri m'dziko langa, putty wosamva madzi komanso wosapaka malo otetezedwa ndi chilengedwe wakhala amtengo wapatali kwambiri ndi anthu. Amapangidwa ndi acetal reaction ya vinyl mowa ndi formaldehyde. Choncho, nkhaniyi pang'onopang'ono inathetsedwa ndi anthu, ndi mapadi etere mndandanda mankhwala ntchito m'malo nkhaniyi. Izi zikutanthauza kuti, pakupanga zida zomangira zachilengedwe, cellulose ndiyo yokhayo. Mu putty yosagwira madzi, imagawidwa m'mitundu iwiri: ufa wowuma wa putty ndi putty phala. Mwa mitundu iwiriyi ya putty, methyl cellulose yosinthidwa ndi hydroxypropyl methyl iyenera kusankhidwa. Mawonekedwe a viscosity nthawi zambiri amakhala pakati pa 30000-60000cps. Ntchito zazikulu za cellulose mu putty ndikusunga madzi, kugwirizana ndi kudzoza. Popeza makonzedwe a putty a opanga osiyanasiyana ndi osiyana, ena ndi imvi kashiamu, kashiamu wopepuka, simenti yoyera, etc., ndipo ena ndi gypsum ufa, imvi kashiamu, calcium kuwala, etc., kotero specifications, mamasukidwe akayendedwe ndi malowedwe a mapadi mu njira ziwiri ndi zosiyana. Ndalama zomwe zawonjezeredwa ndi pafupifupi 2 ‰-3 ‰. Pomanga khoma scraping putty, popeza m'munsi mwa khoma ali ndi mlingo wina wa mayamwidwe madzi (mayamwidwe madzi mayamwidwe khoma la njerwa ndi 13%, ndi mlingo mayamwidwe madzi konkire ndi 3-5%), kuphatikiza ndi evaporation ya dziko lakunja, ngati putty kutaya madzi mofulumira kwambiri , Zidzatsogolera ku ming'alu kapena kuchotsa ufa, zomwe zidzafooketsa mphamvu ya putty. Choncho, kuwonjezera cellulose ether kuthetsa vutoli. Koma khalidwe la filler, makamaka khalidwe la phulusa calcium ndi zofunika kwambiri. Chifukwa cha kukhuthala kwakukulu kwa cellulose, kuyanika kwa putty kumakulitsidwanso, ndipo kugwedezeka kwapanthawi yomanga kumapewedwanso, ndipo kumakhala komasuka komanso kopulumutsa ntchito pambuyo pakupala. Ndikosavuta kuwonjezera pa cellulose ether mu powder putty. Kupanga ndi kugwiritsa ntchito kwake ndikosavuta. Zodzaza ndi zowonjezera zimatha kusakanikirana mofanana mu ufa wouma.
 
(3) Dongo la konkriti:
Mu matope a konkire, kuti mukwaniritse mphamvu zomaliza, simenti iyenera kukhala ndi madzi okwanira. Makamaka pomanga chilimwe, matope a konkire amataya madzi mofulumira kwambiri, ndipo miyeso ya hydration yathunthu imagwiritsidwa ntchito kusunga ndi kuwaza madzi. Kuwonongeka kwazinthu ndi ntchito yovuta, chinsinsi ndichakuti madziwo ali pamtunda, ndipo hydration yamkati ikadali yosakwanira, kotero njira yothetsera vutoli ndikuwonjezera othandizira asanu ndi atatu osungira madzi ku konkire yamatope, nthawi zambiri amasankha hydroxypropyl methyl. kapena methyl Cellulose, mawonekedwe a viscosity ali pakati pa 20000-60000cps, ndipo kuchuluka kwake ndi 2% -3%. Mlingo wosungira madzi ukhoza kuwonjezeka kufika pa 85%. Njira yogwiritsira ntchito konkire yamatope ndikusakaniza ufa wouma mofanana ndikutsanulira m'madzi.
 
(4) Popaka gypsum, gypsum yomangika, gypsum yokhotakhota:
Ndi chitukuko chofulumira cha ntchito yomanga, kufunikira kwa anthu kwa zomangira zatsopano kukukulirakuliranso tsiku ndi tsiku. Chifukwa chakuchulukirachulukira kwa anthu pakuzindikira zachitetezo cha chilengedwe komanso kuwongolera mosalekeza kwa zomangamanga, zida za simenti za gypsum zakula mwachangu. Pakalipano, zinthu zodziwika bwino za gypsum ndizo pulasitala gypsum, gypsum yomangirira, gypsum yopaka, ndi zomatira matailosi. Plastering gypsum ndi pulasitala wapamwamba kwambiri pamakoma amkati ndi kudenga. Khoma lopakidwa nalo ndi labwino komanso losalala. Chomatira chatsopano cha board board ndi chinthu chomata chopangidwa ndi gypsum monga maziko ake ndi zowonjezera zosiyanasiyana. Ndizoyenera kulumikizana pakati pa zida zosiyanasiyana zomanga khoma. Sichiwopsezo, Chopanda fungo, mphamvu yoyambirira komanso kukhazikika mwachangu, kulumikizana mwamphamvu ndi mawonekedwe ena, ndizinthu zothandizira matabwa omangira ndi kumanga chipika; gypsum caulking agent ndi chodzaza mipata pakati pa matabwa a gypsum ndi chokonzera makoma ndi ming'alu. Zogulitsa za gypsumzi zimakhala ndi ntchito zosiyanasiyana. Kuphatikiza pa ntchito ya gypsum ndi zowonjezera zowonjezera, nkhani yaikulu ndi yakuti zowonjezera zowonjezera za cellulose ether zimagwira ntchito yaikulu. Popeza gypsum amagawidwa mu gypsum anhydrous ndi hemihydrate gypsum, osiyana gypsum ali ndi zotsatira zosiyana pa ntchito ya mankhwala, kotero thickening, posungira madzi ndi retardation kudziwa khalidwe la gypsum zomangira. Vuto lodziwika bwino la zidazi ndikubowola ndi kung'ambika, ndipo mphamvu zoyambira sizingafikire. Pofuna kuthetsa vutoli, ndikusankha mtundu wa cellulose ndi njira yogwiritsira ntchito pawiri ya retarder. Pachifukwa ichi, methyl kapena hydroxypropyl methyl 30000 nthawi zambiri amasankhidwa. -60000cps, ndalama zowonjezera ndi 1.5% -2%. Pakati pawo, cellulose imayang'ana kwambiri kusunga madzi komanso kuchepetsa mafuta. Komabe, ndizosatheka kudalira cellulose ether monga retarder, ndipo m'pofunika kuwonjezera citric acid retarder kusakaniza ndi kugwiritsa ntchito popanda kukhudza mphamvu yoyamba. Kusunga madzi nthawi zambiri kumatanthauza kuchuluka kwa madzi omwe angatayike mwachilengedwe popanda kuyamwa kwamadzi kunja. Ngati khomalo ndi louma kwambiri, kuyamwa kwamadzi ndi kutuluka kwachilengedwe pamtunda kumapangitsa kuti zinthuzo zitaya madzi mwachangu, ndipo kung'ambika ndi kung'ambika kumachitikanso. Njira yogwiritsira ntchitoyi imasakanizidwa ndi ufa wouma. Ngati mukukonzekera yankho, chonde onani njira yokonzekera yankho.
 
(5) Mtondo wosungunula matenthedwe
Insulation mortar ndi mtundu watsopano wazinthu zotchingira khoma m'chigawo chakumpoto. Ndi khoma lazinthu zopangidwa ndi zinthu zotsekemera, matope ndi binder. Pankhani iyi, cellulose imagwira ntchito yofunika kwambiri pakulumikizana ndikuwonjezera mphamvu. Nthawi zambiri sankhani methyl cellulose yokhala ndi kukhuthala kwakukulu (pafupifupi 10000eps), mlingo nthawi zambiri umakhala pakati pa 2 ‰ -3 ‰), ndipo njira yogwiritsira ntchito ndikusakaniza ufa wowuma.
 
(6) mawonekedwe wothandizira
Sankhani HPNC 20000cps kwa wothandizira mawonekedwe, sankhani 60000cps kapena kuposerapo kwa zomatira matailosi, ndipo yang'anani pa thickener mu mawonekedwe othandizira, omwe amatha kupititsa patsogolo mphamvu zamakokedwe ndi mphamvu zotsutsa-muvi. Amagwiritsidwa ntchito ngati chosungira madzi pomangirira matailosi kuti tilepheretse kutaya madzi mwachangu komanso kugwa.
 
3. Makampani unyolo mkhalidwe
(1) Makampani akumtunda
Zida zazikulu zomwe zimafunikira kupanga mapadi a cellulose ether ndi thonje loyengedwa (kapena zamkati zamatabwa) ndi zosungunulira zina zamankhwala, monga propylene oxide, methyl chloride, madzi a caustic koloko, caustic koloko, ethylene oxide, toluene ndi zida zina zothandizira. Mabizinesi akumtunda amakampaniwa akuphatikiza thonje woyengedwa, mabizinesi opangira matabwa ndi mabizinesi ena amankhwala. Kusinthasintha kwamitengo yazinthu zazikulu zomwe tatchulazi kudzakhala ndi magawo osiyanasiyana pamtengo wopangira komanso mtengo wogulitsa wa cellulose ether.
 
Mtengo wa thonje woyengedwa ndi wokwera kwambiri. Kutengera zomangira kalasi mapadi etero Mwachitsanzo, pa nthawi malipoti, mtengo wa thonje woyengedwa mlandu 31,74%, 28,50%, 26,59% ndi 26,90% ya malonda mtengo wa zomangira kalasi mapadi efa motero. Kusinthasintha kwamtengo wa thonje woyengedwa kudzakhudza mtengo wopangira cellulose ether. Zopangira zazikulu zopangira thonje woyengedwa ndi ma linter a thonje. Makatani a thonje ndi amodzi mwazinthu zomwe zimagwiritsidwa ntchito popanga thonje, zomwe zimagwiritsidwa ntchito kwambiri popanga zamkati za thonje, thonje woyengedwa, nitrocellulose ndi zinthu zina. Mtengo wogwiritsira ntchito ndi kugwiritsa ntchito zingwe za thonje ndi thonje ndizosiyana kwambiri, ndipo mtengo wake mwachiwonekere ndi wotsika kuposa wa thonje, koma uli ndi mgwirizano wina ndi kusinthasintha kwa mtengo wa thonje. Kusinthasintha kwamitengo ya matumba a thonje kumakhudza mtengo wa thonje woyengedwa.
 
Kusinthasintha kwakukulu kwamtengo wa thonje woyengedwa kudzakhala ndi magawo osiyanasiyana pakuwongolera ndalama zopangira, mitengo yamtengo wapatali komanso phindu la mabizinesi pamsika uno. Pamene mtengo wa thonje woyengedwa ndi wokwera komanso mtengo wamtengo wapatali wamtengo wapatali ndi wotsika mtengo, pofuna kuchepetsa ndalama, matabwa a matabwa angagwiritsidwe ntchito m'malo mwa thonje loyengedwa, makamaka popanga ma cellulose ethers okhala ndi kukhuthala kochepa monga mankhwala ndi chakudya kalasi cellulose ethers. Malinga ndi zomwe zachokera patsamba la National Bureau of Statistics, mchaka cha 2013, malo obzala thonje m'dziko langa anali mahekitala 4.35 miliyoni, ndipo thonje ladziko lonse lapansi linali matani 6.31 miliyoni. Malinga ndi ziwerengero zochokera ku China Cellulose Industry Association, mu 2014, thonje woyengedwa wopangidwa ndi opanga thonje woyenga bwino wapakhomo anali matani 332,000, ndipo zopangira ndizochuluka.
 
Zida zazikulu zopangira zida zamakina a graphite ndi chitsulo ndi graphite carbon. Mtengo wa chitsulo ndi mpweya wa graphite umakhala wokwera kwambiri pamtengo wopangira zida zamakina a graphite. Kusinthasintha kwamitengo ya zinthu izi kudzakhala ndi vuto linalake pamtengo wopangira komanso kugulitsa mtengo wa zida zamankhwala a graphite.
 
(2) Makampani otsika a cellulose ether
Monga "industrial monosodium glutamate", cellulose ether ali ndi gawo lochepa la cellulose ether ndipo ali ndi ntchito zosiyanasiyana. Mafakitale akumunsi amwazikana m'mbali zonse zachuma chadziko.
 
Nthawi zambiri, makampani omanga kumunsi ndi malonda ogulitsa nyumba adzakhala ndi zotsatirapo zina pakukula kwa kufunikira kwa zinthu zomangira ma cellulose ether. Pamene makampani omanga m'nyumba ndi malo ogulitsa nyumba akukulirakulira, kufunikira kwa msika wapakhomo pazomangamanga zama cellulose ether kukukulirakulira. Pamene kukula kwa makampani omanga m'nyumba ndi makampani ogulitsa nyumba kumachepetsa, kukula kwa kufunikira kwa zinthu zomanga kalasi ya cellulose ether pamsika wapakhomo kudzachepa, zomwe zidzakulitsa mpikisano mumakampani awa ndikufulumizitsa njira yopulumukira. zabwino kwambiri pakati pa mabizinesi mumakampani awa.
 
Kuyambira mchaka cha 2012, pokhudzana ndi kuchepa kwa ntchito yomanga nyumba ndi malo ogulitsa nyumba, kufunikira kwa zinthu zomangira ma cellulose ether pamsika wapakhomo sikunasinthe kwambiri. Zifukwa zazikulu ndi izi: 1. Kuchuluka kwa ntchito yomanga nyumba ndi malo ogulitsa nyumba ndi aakulu, ndipo kufunikira kwa msika ndi kwakukulu; msika waukulu wa ogula wa zinthu zomangira kalasi mapadi ether pang'onopang'ono ikukula kuchokera kumadera otukuka zachuma ndi mizinda yoyamba ndi yachiwiri-tier kumadera apakati ndi kumadzulo ndi mizinda yachitatu, kukula kwa zofuna zapakhomo ndi kukula kwa malo; 2. Kuchuluka kwa cellulose ether anawonjezera nkhani za gawo lochepa la mtengo wa zipangizo zomangira. Ndalama zomwe zimagwiritsidwa ntchito ndi kasitomala m'modzi ndizochepa, ndipo makasitomala amabalalika, zomwe zimakhala zovuta kufunafuna. Zofunikira zonse pamsika wakumunsi ndizokhazikika; 3. Kusintha kwa mtengo wamsika ndi chinthu chofunikira chomwe chikukhudza kusintha kwa kapangidwe kazinthu zomangira ma cellulose ether. Kuyambira 2012, mtengo wogulitsa wa zinthu zomangira kalasi cellulose ether watsika kwambiri, zomwe zachititsa kutsika kwakukulu kwa mtengo wapakati mpaka-pamwamba-mapeto mankhwala, kukopa makasitomala ambiri kugula ndi kusankha , kuonjezera kufunika kwa m'ma mpaka. -Zogulitsa zapamwamba, ndikufinya kufunikira kwa msika ndi malo amtengo wamitundu wamba.
 
Mlingo wa chitukuko chamakampani opanga mankhwala komanso kukula kwamakampani opanga mankhwala kudzakhudza kufunika kwa mankhwala a cellulose ether. Kuwongolera kwa moyo wa anthu komanso makampani otukuka azakudya ndiwothandiza pakuyendetsa kufunikira kwa msika wama cellulose ether.
 
6. Chikhalidwe cha chitukuko cha cellulose ether
Chifukwa cha kusiyana kwamapangidwe a msika wa cellulose ether, makampani omwe ali ndi mphamvu ndi zofooka zosiyanasiyana amatha kukhalira limodzi. Poona kusiyanitsa koonekeratu kwamapangidwe a msika, opanga mapadi a cellulose ether atengera njira zosiyanitsira mpikisano potengera mphamvu zawo, ndipo nthawi yomweyo, akuyenera kumvetsetsa momwe msika ukuyendera bwino komanso momwe msika ukuyendera.
 
(1) Kuwonetsetsa kuti kukhazikika kwazinthu kudzakhalabe malo opikisana nawo mabizinesi a cellulose ether
Ma cellulose ether amawerengera gawo laling'ono la ndalama zopangira mabizinesi ambiri akumunsi mumsika uno, koma zimakhudza kwambiri mtundu wazinthu. Magulu amakasitomala apakati mpaka apamwamba akuyenera kuyesa mayeso asanagwiritse ntchito mtundu wina wa cellulose ether. Pambuyo popanga chilinganizo chokhazikika, nthawi zambiri zimakhala zovuta kusintha mitundu ina yazinthu, ndipo panthawi imodzimodziyo, zofunikira zapamwamba zimayikidwa pa kukhazikika kwa khalidwe la cellulose ether. Chodabwitsa ichi ndi chodziwika kwambiri m'magawo apamwamba monga opanga zida zazikulu zomangira kunyumba ndi kunja, zopangira mankhwala, zowonjezera zakudya, ndi PVC. Pofuna kupititsa patsogolo mpikisano wazinthu, opanga ayenera kuonetsetsa kuti khalidwe ndi kukhazikika kwa magulu osiyanasiyana a cellulose ether omwe amapereka akhoza kusungidwa kwa nthawi yaitali, kuti apange mbiri yabwino ya msika.
 
(2) Kuwongolera mulingo waukadaulo wogwiritsa ntchito mankhwala ndi njira yachitukuko yamabizinesi apanyumba a cellulose ether
Ndi ukadaulo wochulukirachulukira wopangira ma cellulose ether, luso lapamwamba laukadaulo wogwiritsa ntchito limathandizira kupititsa patsogolo kupikisana kwamabizinesi ndikupanga ubale wokhazikika wamakasitomala. Makampani odziwika bwino a cellulose ether m'maiko otukuka amatengera njira yopikisana ya "kuyang'anizana ndi makasitomala akuluakulu + omwe akupanga magwiritsidwe ntchito ndi magwiritsidwe apansi pamtsinje" kuti apange ma cellulose ether omwe amagwiritsa ntchito komanso mawonekedwe ogwiritsira ntchito, ndikukonza zinthu zingapo molingana ndi magawo osiyanasiyana ogawidwa. kupangitsa kuti makasitomala agwiritse ntchito, komanso kukulitsa kufunikira kwa msika. Mpikisano wamabizinesi a cellulose ether m'maiko otukuka wachoka pakulowa kwazinthu kupita kuukadaulo wogwiritsa ntchito