K-Resin

Proportion of Hard Segments. As expected, the modulus of styrenic block copolymers increases with the proportion of the hard polystyrene segments. The tensile behavior of otherwise similar block copolymers with a wide range of polystyrene contents shows a family of stress—strain curves (4,7,8). As the styrene content is increased, the products change from very weak, soft, mbbedike materials to strong elastomers, then to leathery materials, and finally to hard glassy thermoplastics. The latter have been commercialized as clear, high impact polystyrenes under the trade name K-Resin (39) (Phillips Petroleum Co.). Other types of thermoplastic elastomers show similar behavior that is, as the ratio of the hard to soft phase is increased, the product in turn becomes harder. 

K-Resin Phillips branched B very high polystyrene content ... 

Tbe system may be used for homopolymers and for block copolymers. Some commercial SBS triblock thermoplastic rubbers and the closely related K-resins produced by Phillips are of this type. Anionic polymerisation methods are of current interest in the preparation of certain diene rubbers. 

Closely related to these but thermoplastic rather than rubber-like in character are the K-resins developed hy Phillips. These resins comprise star-shaped butadiene-styrene block copolymers containing about 75% styrene and, like SBS thermoplastic elastomers, are produced by sequential anionic polymerisation (see Chapter 2). 

Table 16.6 Some typical properties of styrene-butadiene block copolymer thermoplastics (Phillips K-Resins)...

Elexar, Monoprene, Tekron, Tekbond K-Resin, Solprene Tufprene, Asaprene, Asaflex... 

Kraton D, Cariflex TR, Taipol, Vector, Tufprene, Asaprene, Calprene, Europrene Sol T, Stearon, Flexprene, Quintac, Finaprene, Coperbo, Solprene, Stearon, and K-Resin. These products may be branched or linear with varying contents of the various components. 

K-Resin Butadiene-styrene copolymer Phillips Petroleum... 

Estrous cycle disruption effect. Ethanol (95%) extract of the dried aerial parts, administered intraperitoneally to gerbils at a dose of 2.5 mg/animal daily for 60 days, was active . Petroleum ether extract of the dried aerial, administered intraperitoneally to mice and rats at doses of 1 and 5 mg/animal, respectively, for 64 days, was active . Petroleum ether extract of the aerial parts, administered intraperitoneally to female rats, produced weak activity " h Petroleum ether extract of the entire plant, administered by gastric intubation to female mice at doses of 75 mg/kg and 150 mg/kg, was active. A dose of 3 mg/kg produced weak activity ". Petroleum ether extract of the resin, administered intraperitoneally to female rats at doses of 10 and 20 mg/kg, was active k Resin, administered orally to female rats at doses of 3, 15, and 75 mg/kg daily for 72 days, was active . 

This ABA block copolymer consists of stiff polystyrene (PS) and resilient polybutadiene blocks. The domains of these TPEs have characteristic Tt values of 100 and —80 C, respectively. The polybutadiene blocks retain their flexibility at low temperatures, and the polystyrene blocks lose their stiffness when the polymer is heated above 110 C. A related thermoplastic is a transparent AB block copolymer of styrene and butadiene (K-resin). 

X. Dong, G. Geuskens, and C. A. Wilkie, Graft copolymers of melhaciylic acid and SBS and K-Resin by the... 

Styrene-butadiene block copolymers such as Kraton , K-Resin , Styro-lux and Styroflex are examples of the versatility of this method and have long been manufactured via anionic polymerization on a commercial scale. 

The development of high styrene content styrene-butadiene copolymers (SBCs), such as K-Resin SBC, is best thought of as a branch off the history of anionic polymerization and rubber. A number of excellent reviews cover this aspect of the subject in great detail, and should be obtained for detailed examination of the history of rubber and anionically synthesized rubber polymers [1-3]. What follows is a brief overview to fit the high styrene content SBC into a historical context. 

K-Resin SBC was invented by Alonzo Kitchen, a research chemist at Phillips Petroleum Research and Development laboratories. With inventorship came the opportunity to name the new resin, which he called K-Resin . The first pilot plant resins were made in 1967, and commercial samples were prepared for test marketing in 1968. Commercial production started in October of 1972 at the SBC plant in Borger, Texas, on a 10 million pound per year capacity line. Initially, the solution product was steam stripped to remove the hydrocarbon solvent, but this left a significant haze in the resin. The finishing system was quickly converted to a devolatilizing extruder. Commercial production continued at this plant until 1979, ending with the opening of a new production facility at Adams Terminal (later renamed the Houston Chemical Complex) in Pasadena, Texas. The new plant had a nameplate capacity of 120 million pounds per year. Plant expansions increased the production capacity in 1988 and 1994 to a total nameplate capacity around 300 million pounds per year. 

K-Resin SBC synthesis is a batch anionic solution polymerization of styrene and 1,3-butadiene using an n-butyllithium (NBL) initiator in a process referred to as living polymerization . Although often referred to as a catalyst, each NBL gives rise to a distinct polymer chain. Polymer chains grow by adding monomer... 

Figure 22.5 Film properties of K-Resin SBC grades (DK11 and DK13) 1 mil film...

Table 22.7 Physical properties of blends of K- Resin H SBC and styrene-acrylonitrile copolymer"... 

Table 22.10 Physical properties 50 50 K-Resin SBC-GPPS 20 mil blended sheet modified with Dow XL 8028 HIPS...

Hinge Life Study of K-Resin i Blends, Plastics Technical Center Report 421, Chevron Phillips Chemical Co., Bartlesville, OK. 

Fig. 2 Chromatograms of GOS (K resins) and FOS (Ca resins) with different DVB content (8%, 4%, and 2% DVB), injection volume 1 ml, concentration 100 g syrup/1, flow rate 0.S4S ml/min, temperature 60°C.

When block copolymers have broad molecular weight distributions or when blends of monodisperse block copolymers are prepared, the morphologies may be more complex and are no longer determined by considerations of copolymer composition alone. An example of this is found in the two commercially available K-Resin block copolymers, both of which contain 23 wt % polybutadiene and 77 wt % polystyrene. KRO-1 = 179 Si = 132 kg/mole) exhibits a morphology best described as an interconnected network of randomly wavy cylinders of polybutadiene in a polystyrene matrix as shown in Fig. 10a, whereas KRO-3 = 217 = 106 kg/... 

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