Ko te Ngongo Porowhita Whakakaha Kirihou Polyurethane (PU) he ngongo mahi-teitei, maha-kaupapa i hangaia hei whakatutuki i ngā tono pakari o ngā mahi ahumahi, arumoni, me te ahuwhenua. Ko tōna hanganga matua e whakakotahi ana i te pakitara o roto PU maeneene, ātete-kakahu me te whakakaha porowhita kirihou whakauru (he waea rino whakakikorua-parahi rānei hei whakakapi mō te marara pateko), e tuku ana i te taurite kore e taea te whakataurite o te ngāwari, te kaha, me te manawanui.
Tuatahi, mā te hanganga o ngā rauemi ka roa te ora: ko te ngongo PU (he mea hanga ki te polyester) e whakamanamana ana ki te pakeketanga o Shore A o te 95±2, e whakarato ana i te ātete pai ki te pakaru, te haehae, me te pānga—e 3–5 ngā wā e pai ake ana i ngā momo rapa, PVC rānei i roto i ngā āhuatanga kakahu nui (hei tauira, te whakawhiti i ngā rauemi kirikiri pēnei i te sima, te witi rānei). Ka whakakorehia e te whakakaha porowhita kirihou te hiahia mō ngā waea whakarewa taumaha (ki te kore e tohua) me te pupuri tonu i te hanganga, ka taea ai e te ngongo te tu atu ki ngā pēhanga pai tae atu ki te 10 pae me ngā pēhanga kino (momi) o te -0.9 pae, e pai ai mō te tuku me te whakahaere rauemi i runga i te korehau.
Tuarua, he whānui te urutau ki te taiao: he pono te mahi i ngā pāmahana mai i te -40°C ki te 90°C (me te manawanui poto ki te 120°C), he ngāwari tonu ahakoa i te tino makariri (kāore i rite ki ngā ngongo PVC pakari) ā, he ātete ki te whakarerekētanga i ngā taiao wera nui. Hei tāpiri, ko te putanga kai-kai (e tutuki ana ki ngā paerewa EU 10/2011 me te FDA) kāore he phthalates, BPA, me ngā konganuku taumaha, he mea haumaru mō te whakawhiti i ngā wai e taea te kai (wai, waina, miraka) me ngā kai maroke rānei—he mea nui mō te tukatuka kai me te hanga inu. Mō te whakamahinga ahumahi, he tino ātete matū ki ngā hinu, ngā waikawa ngawari, ngā kawakore, me ngā whakarewa, e karo ana i te pirau i roto i ngā āhuatanga mahi uaua.
Tuatoru, ko tōna hoahoa e aro ana ki te kaiwhakamahi ka whakarei ake i te whai huatanga o te mahi: ko te pakitara o roto tino maeneene (Ra < 0.5 μm) ka whakaiti i te ngaronga o te waku, ka whakarite kia kore e araia te rere o ngā wai, ngā paura, ngā hau rānei, me te ārai i te kohikohinga toenga (ka māmā ake te horoi me te whakaiti i ngā utu tiaki). Ko te hanganga mama (≈30% te mama ake i ngā ngongo rapa o te diameter kotahi) me te hanganga porowhita ātete-piko ka taea te nekeneke ngāwari, te piko, me te takai - he pai mō ngā wāhi kuiti (hei tauira, te hauhautanga mīhini, ngā wāhanga miihini kaipuke) me ngā tono pūkoro rānei (hei tauira, ngā rehu ahuwhenua, ngā papu papa hanga). Ko ngā rahi ka taea te whakarite (diameter o roto: 25mm–300mm; matotoru pakitara: 0.6mm–2mm) me ngā kōwhiringa tae (mārama, mangu, ritenga rānei) ka urutau atu ki ngā hiahia motuhake, mai i te whakawhiti wai taiwhanga iti ki te kawe paru keri nui.
Hei whakamutunga, ka whānuitia tōna whakamahinga puta noa i ngā ahumahi: i roto i te ahuwhenua, ka mahi hei raina whakamakuku, hei ngongo momi/tukunga papu rānei; i roto i te hanga, ka mahi hei awa hau mō ngā mīhini kakahu, hei paipa kohikohi puehu rānei mō ngā taputapu whakakanapa whakarewa; i roto i te tukatuka kai, ka whakawhiti i ngā kai i waenga i ngā wāhanga whakaputa; ā, i roto i te keri maina, ka whakahaere i ngā matūriki konganuku whakakoi. Ko ngā putanga whakakore-pūmau whiriwhiri (me te whakakaha waea maitai whenua, te ātete < 10² ohm/m) ka tāpiri haumaru mō te whakawhiti rauemi mura, ka whakaiti i te mōrearea o te tukunga hiko pūmau.
Hei whakarāpopototanga, ka whakakotahihia e tēnei ngongo te mahi pakari, te tutuki i ngā whakaritenga akuaku, me te ngāwari o te whakahaere—ka waiho hei otinga utu-whai hua, roa-te-roa mō ngā wero whakahaere rauemi kanorau.