Novel olefin copolymers emerge.

For the last two years, Himont Incorporated in Wilmington, Del., has quietly been developing an unusual slate of heterophasic olefin copolymers with high impact strength and excellent puncture and tear resistance. These resins are the first commercial fruits of its much-touted Catalloy process for which a brand-new plant was built in Bayport, Texas. Some inkling of what Catalloy could do was revealed at the K'92 show in Germany when Himont showed off similar materials made by a sister Catalloy plant in Italy (see PT, March ,93, p. 29). Last month, Himont went public with the first commercial U.S. grades and some of their early applications.

There are some 17 to 20 commercial grades presently being made here by this unusual reactor-alloying process. Catalloy-process materials are predominantly ethylene/propylene, but some incorporate other olefinic monomers, and some are terpolymers. All have low density (around 0.9 g/cc). They,re said to run on existing machinery for HDPE or LDPE, and are priced at 55[cts.]-$1/lb.

[TABULAR DATA 1 OMITTED]

Himont categorizes the new resins in three families: flexible, very flexible, and specialty. They can be processed by all thermoplastic methods, including air-quenched blown film, cast film, extrusion coating, injection molding, blow molding, extruded sheet, coextrusion and calendering, Himont says. Broad melting range reportedly aids calendering, while low draw resonance permits high throughputs in cast film.

HIGH-STRENGTH FILMS

Flexible grades for extrusion and blow molding (Table 2) are characterized by excellent chemical resistance, good moisture resistance, calenderability, and heat resistance suitable for autoclave, hot-fill, or under-hood applications. Grade KS 077 is aimed at industrial sacks, where it's said to show higher strength than LLDPE or rubber modified HDPE at equal thickness. It also boasts high coefficient of friction to permit secure palletizing without need for adhesives. It's being tested by Himont for resin pellet sacks. Sacks made of KS 077 film 4.9 mils thick reportedly outperform 7-mil LLDPE bags in drop tests. In a quite different application, medical/sanitary/hygienic film, 0.6-mil KS 077 film can replace 1.25-mil octene-copolymer LLDPE. (CIRCLE 21)

TABLE 2--FLEXIBLE CATALLOY-PROCESS
EXTRUSION GRADES
            MFR,
Grade      g/10 min    Application
KS 026P     0.8        Autoclave bags
KS 077P     0.8        Industrial bags
KS 021P     0.9        Blown, cast film
KS 063P     1.0        Medical packaging
KS 031P     5.5        Flexible cast film

An autoclavable grade KS 026P is used for orange biohazard-disposal bags. These bags have to be sterilized before disposal. And KS 021 is being used for extrusion blow molded, soft-feel squeeze bottles for a liquid bath soap in France. KS 021 has psi and is also recmodulus of 55,000 psi and is also recommended as an impact modifier for PP. (CIRCLE 22)

ULTRA-SOFT GRADES

Ultra-soft extrusion grades (Table 3) are low-crystallinity resins with broad melting ranges. This affords them a broad processing window. Grade KS 068P is used commercially by JPS Elastomerics Corp. in Northhampton, Mass., to make calendered geomembranes. These Catalloy process resins are calendered into 40-mil, unreinforced geomembranes as well as 45-mil, polyesterscrim-reinforced products. The material's low coefficient or thermal expansion (less than 1%) prevents stress on hot-welded seams in landfills. Another advantage of these highly flexible liners is that they can be "festooned." or folded back and forth and shipped in boxes like PVC, whereas PE is weakened by creases and must be shipped on gigantic 40-ft rolls. (CIRCLE 23)

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EASY SEALING & SUPER-TOUGH

What Himont terms "specialty" resins from the Catalloy process (Table 4) include two groups of materials-one for low seal-initiation temperature and one with extremely high toughness for injection molding. Within the first family, grade KT 021 is aimed at hot-tack layers in BOPP film for snack food packaging. It has a seal-initiation temperature of 105 C (221 F), the lowest of any domestic copolymer, Himont says. Next closest is 240 F heat seal, Himont says.

TABLE 4--SPECIALTY CATALLOY-PROCESS GRADES
Seal       MFR,        Init.
Layer     g/10 min     Temp.           Application
KT 021P    4.0         221 F             Hot tack
KT 012P    5.0         240 F             Hot tack
Inject.    MFR,
Molding   g/10 min    Flex. Mod., psi  Application
KS 059P    10.0        18,000            Super tough
KS 041P    10.0        65,000            Super tough

Himont is currently developing a low-temperature sealing grade that may be the lowest anywhere--84 C (183 F). So far, it's only being made in pilot plant quantities. Several Japanese resin producers are believed to make copolymers with hot-tack temperatures down to about 185 F. (CIRCLE 24)

One of two super-tough injection molding grades KS 059P, is commercial in black molded boot tops for blade-type roller skates and ice skates. The low density (0.89) gives it an advantage in being light weight. KS 059 also shows a "No Break" notched Izod at -4 F. It can replace nylon with "only minor modifications" to existing injection mold tooling, Himont says. (CIRCLE 25)