Polyester-based TPU

However, TPU has several disadvantages (1) its high price (currently TPU is at least four times the cost of PVC), (2) its narrow temperature range for processing, and (3) its tendency to be hydrolyzed especially in the case of polyester-based TPU. 

Differential scanning calorimetry (DSC) is fast, sensitive, simple, and only needs a small amount of a sample, therefore it is widely used to analyze the system. For example, a polyester-based TPU, 892024TPU, made in our lab, was blended with a commercial PVC resin in different ratios. The glass transition temperature (Tg) values of these systems were determined by DSC and the results are shown in Table 1. 

In some cases, satisfactory TPU cannot be found from commercial sources and synthesis is necessary. Since the polyester-based TPU is more frequently used for... 

Several commercial products of PVC/TPU blends are available. The BF Goodrich Chemical Group has a PVC/ TPU blend based on their Estane series TPUs. For example, their Estane 54620, a polyester-based TPU with a °ShA 85 hardness, shows excellent compatibility with flexible PVC. The blends are produced by mixing PVC, TPU, plasticizer, stabilizer, and lubricant in a twin-screw extruder. These polymeric blends show intermediate mechanical properties between PVC and TPU. 

A few noncommercial PVC/TPU systems have been reported. Makarof et al. [13] reported a polymer blend of PVC and polyester-based TPU. The TPU series were made from a polyesterglycol (composed of butanediol... 

A series of polyester-based TPU (566TPU series) were synthesized in our lab and used to blend with PVC to manufacture a modified PVC material for medical uses [14]. Morphological studies showed that 566TPU has very good compatibility with PVC. Detailed mechanical and electronic property tests were also conducted. Some of the data are provided in Tables 3 and 4. 

A series of tests [15] were conducted to compare three types of polymeric modifiers for PVC Du Ponf s Elva-loy 741, a copolymer of ethylene, vinylacetate, and carbon monoxide Goodyear s Chemigum P83, a copolymer of butadiene and acrylonitrile and 566TPU from our lab, a polyester-based TPU. Some of the results are provided in Tables 5 and 6. 

The statements made regarding polyurethane (Section 5.5.9.14) also apply to hydrolysis resistance of TPUs. Polyether-based TPU is considerably more resistant to hydrolysis than polyester-based TPU because of its chemical structure. Rigid TPUs are also typically more resistant than soft ones, because the hard segments in the polymer molecule do not hydrolyze as quickly. 

The 12C Series of low melting polyester-based TPU is currently being developed for a wide range of specialty engineering plastics. The interesting thermal and rheological properties of this series provide enhanced compatibility with a wide variety of other thermoplastics. 

The polyester-based TPU of the 12K Series are very clear, gel free, low color, and easy to extrude film-forming materials of both high and medium... 

Both polyester- and polyether-based TPU could be used to blend with PVC, although the former constitutes the majority of the commercial products. All of the blends should meet the following requirements (I) they must have good or relatively good compatibility with PVC, (2) their processing temperature should be close to or lower than that of PVC, (3) they have to meet the specific requirements of the products, for example, TPUs used for medical purposes should be colorless (if possible), transparent, nontoxic, and able to be sterilized, and (4) they should not be expensive. 

TPU) and either aromatic or aliphatic. Aliphatics are more expensive, but generally have better resistance to ultraviolet radiation and are clearer. PUs are also either polyether-based or polyester-based, where the former has better low temperature flexibility and the latter tends to be tougher and more chemical resistant. 

Table A.40 Swelling behavior of TPU in solvent (3 weeks at 20 °C) results reflect tests with two grades of Elastollan two TPUs based on polyester, one TPU based on polyether [867]...

Material. A thermoplastic polyurethane (TPU) is injection molded from melts of different temperature. The material is a commercial grade polyester based thermoplastic polyurethane (TPU) with 94 Shore A durometer hardness from Huntsman Inc., e.g. for sealing applications. The TPU has been polymerized in a one-step process and is provided in granular form ground from cast film. 

All TPE products, irrespective of type, are listed alphabetically by manufacturer s name with the first appearing on the following pages Polyurethane based (PUR or TPU and Polyether or Polyester chemistry) Polyester based... 

The thermoplastic polyurethane (TPU) adhesives must, of necessity, contain low gel content because they must be processable in an extruder. Most adhesives are relatively linear, with a functionality of 2.0, although small amounts of branching may be introduced, usually at the expense of a lower melt flow. Good physical properties of TPU s are obtained when the thermoplastic urethanes have molecular weights of 100,000 or higher (see p. 56 in [63]). Most TPU adhesives are based on symmetrical polyesters with a fast crystallizing backbone or a backbone slightly modified to increase the open time. 

Dow Plastics Pellethane t TPU elastomers are based on both polyester and polyether soft segments. ... 

In addition, polyester polyols are made by the reaction of caprolactone with diols. Poly(caprolactone diols) are used in the manufacture of TPU elastomers with improved hydrolytic stability (55). The hydrolytic stability of the polyCcaprolactone dioD-derived TPUs is comparable to TPUs based on the more expensive long-chain diol adipates (56). Polyether/polyester polyol hybrids are synthesized from low molecular weight polyester diols, which are extended with PO. 

The thermoplastic elastomer polyurethanes, TPU, may be of two general types partly crystalline elastic fibers (see preceding paragraph) or softer elastomers, depending on the relative length of the soft segment. Those polyurethanes based on polyester soft segments tend to be more resistant to hydrocarbons, while the polyether types are more resistant to hydrolysis but tend to swell more in aqueous environments (144). The block copolymer characteristics of polyurethanes are discussed further in Chapter 13. 

Polyester TPU can also be protected by carbodiimide-based anti-hydrolysis agents that act as acid interceptors. Service life can be doubled or even quadrupled by such an additive, Table 5.101. Outdoor weathering in central European climate has shown that polyester TPU surfaces are not attacked for up to five years, even without hydrolysis protection. Special hydrolysis protection is required under constant contact with moisture, especially at elevated temperature and/or in tropical climates [673]. 

Jelur 75 TPU elastomer, based on polyester diols. Shore hardness 75° Zaklady Chemiczne Jelchem SA, Jelenia Gora, Poland... 

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