Poliuretan elastomer formed by the polymerization reaction of diisocyanate and active hydrogen compound, the rigid segment containing urea group composed of diisocyanate and diamine chain extender, the glass transition temperature is much higher than room temperature, and it is glassy at room temperature. Subcrystals or microcrystals form the plastic phase; flexible segments of polyether or polyester are gathered together to form the matrix or matrix of the poliuretan rubber. Because its glass transition temperature is lower than room temperature, it is called the rubber phase. The microphase separation of the poliuretan elastomer makes the poliuretan elastomer have the advantages of good wear resistance, wide range of hardness, high strength and high elongation, large load supporting capacity, good shock absorption effect and excellent oil resistance. Choosing a suitable molding and processing method can maximize the performance of poliuretan elastomers and prepare various poliuretan elastomers with excellent properties, which are widely used as plastics, rubber, fibers, adhesives and coatings, and even as functional polymer materials. Such as medical poliuretanbahan
1.1 Prinsip umum kanggo milih cara ngolah mbentuk
(1) Proses pemrosesan biasane kanggo nyawiji utawa mbentuk senyawa polimer ing negara padat (bubuk utawa granular), tempel utawa negara solusi, lan wujud wujud sing dipengini liwat cetakan, lan njaga bentuk sing wis dipikolehi, lan pungkasane entuk produk. proses kerajinan.
(2) Aliran pangolahan cetakan umum: â 'Cara nggawe campuran senyawa polimer kaping siji lan kaping pindho kanggo ngasilake produk; â‘¡Cara nggawe senyawa polimer kanggo ngasilake produk sekaligus; â ‘¢ Cara ngasilake produk saka campuran monomer kanthi sak langkah â‘ £ Cara produksi siji-langkah campuran oligomer.
(3) Kinerja pangolahan lan faktor-faktor pangaribawa: â 'Squeezability, ing extruder, laras mesin injeksi, rol kalender, lan cetakan, nalika bahan kasebut cacat dening ekstrusi, bentuk bahan kasebut dipikolehi lan njaga kemampuan. Faktor sing mbatesi: viskositas lebur, struktur peralatan pangolahan, rheologi lebur lan laju aliran leleh. â‘¡Mableability, ing proses cetakan ing tumindak mesin injeksi, extruder, lan mesin kompresi, bahan kasebut cacat ing tumindak suhu lan tekanan lan kemampuan kanggo dicetak ing cetakan. Faktor sing mbatesi: rheology, sifat termal lan sifat fisik lan mekanik liyane lan reaktivitas kimia senyawa polimer. â ‘¢ Extensibility, ing calendering utawa peregangan, bahan kasebut deformasi kanthi kalender utawa bukaan ing siji utawa rong arah. Faktor sing mbatesi: plastisitas bahan lan efek pengerasan galur. â € £ Spinnability, nozel sajrone cetakan ekstrusi, kemampuan bahan kanggo mbentuk serat padat terus liwat cetakan. Faktor sing mbatesi: rheology, viskositas lan leleh, stabilitas termal lan stabilitas kimia.
1.2 Prinsip umum kanggo milih cara nyetak lan ngolah kanggopoliuretanelastomer
Poliuretan elastomer molding processing system is divided into liquid system and solid system. On the basis of the rapid polymerization reaction of diisocyanate and active hydrogen compound, the molding processing method is conducive to the microphase separation of the poliuretan elastomer. , Liquid system, poliuretan casting glue can be processed by casting (manual casting, centrifugal casting and vacuum casting), reaction injection molding, spraying, knife coating, roller coating, laminating, laminating, bonding, vulcanizing, pasting and rubbing ; Solid system, poliuretan compound rubber can be vulcanized and laminated with mold, poliuretan thermoplastic can be used with thermoplastic, hot injection, calendering, blow molding, spinning and lamination.
1.3 Prinsip sing cocog karo jinis dhasar lan metode pangolahan cetakan
Poliuretanelastomer minangka polimer sing dhuwur ing antarane plastik lan karet ing babagan modulus. Utamane kalebupoliuretan compound rubber, poliuretan cast rubber, poliuretan water emulsion and poliuretan thermoplastic. Poliuretan leather, poliuretan adhesives, poliuretan coatings, poliuretan compounds, poliuretan casting glues, poliuretan fibers, poliuretan water emulsions and poliuretan thermoplastics are all derived from the above four types of glue. The molding and processing methods of poliuretan compound rubber, poliuretan water emulsion and poliuretan thermoplastic generally belong to the molding processing methods of rubber, coatings and plastics.
1.4 The use of poliuretan elastomers and the matching principle of production continuity and molding processing methods
Poliuretan elastomer molding and processing methods are matched with the use of poliuretan elastomers, taking into account the continuity of production. For example, poliuretan leather molding methods usually use poliuretan casting adhesive or foaming layer, poliuretan water emulsion and poliuretan thermoplastic as the surface layer; also available Poliuretan thermoplastic and poliuretan water emulsion are used as leather separately, which are based on the basic rubber molding processing method, supplemented by foam molding processing, usually calender molding processing method is selected. Poliuretan paving materials are made of poliuretan casting glue, mainly due to the large product shape and low precision requirements. Medical poliuretan materials have good chemical stability, tissue compatibility, and resistance to biological aging, so the molding process uses dip coating, pouring and coating methods.
