Acetal Copolymer CELCON

Acetal Copolymer (CELCON ) Two types of non-solvent adhesives are used, structural and non-structural. Most structural adhesives are based on thermoset resins and require the use of a catalyst and/or heat to cure. This type of adhesive is normally used in applications which require maximum bond strength and minimum creep of the adhesive joint under sustained loading. Many structural adhesives can be used continuously at temperatures up to 350 F, which is higher than the 

Non-structural adhesives used on CELCXDN arc usually one-component, room-temperature-curing systems based either on thermoplastic resins or elastomeric materials dispersed in solvents. They are normally used in applications which will not be exposed to temperatures over 180°F. Neoprene rubber adhesives are examples. (7). 

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Acetal Copolymer (CELCON ) As with DELRIN , this is a highly crystalline polymer with excellent solvent resistance. It is somewhat more amenable to solvent cementing than the homopolymer, however. The solvent cement recommended by the manufacturer, Hoechst Celanese, is hexafluoroacetone sesquihydrate, available from Allied Signal, Inc. This solvent is a severe eye and skin irritant, however, and should be handled with care (7). 

Random acetal copolymers (Celcon) have the following repeating unit ... 

The most common types of acetal polymers are the acetal homopolymer (Delrin by Du Pont) and the acetal copolymer (Celcon by Hoescht Celanese-Ticona). The homopolymer is produced from polyformaldehyde and the copolymer from trioxane (a crystalline form of formaldehyde). 

The plastic acetal copolymer (Celcon ) is (made by Ticona Corp., www.ticona.com) a highly crystalline copolymer with excellent solvent and chemical resistance. Two suggested surface-preparation methods are as follows ... 

Throughout the remainder of this article the term homopolymer refers to Delrin acetal resin manufactured and sold by Du Pont the term copolymer refers to Celcon acetal copolymer resins (registered trademark of Hoechst Celanese Corporation). 

The first commercially available acetal resin was marketed by Du Pont in 1959 under the trade name Delrin after the equivalent of ten million pounds had been spent in research or polymers of formaldehyde. The Du Pont monopoly was unusually short lived as Celcon, as acetal copolymer produced by the Celanese Corporation, became available in small quantities in 1960. This material became commercially available in 1962 and later in the same year Farbwerke Hoechst combined with Celanese to produce similar products in Germany (Hostaform). In 1963 Celanese also combined with the Dainippon Celluloid Company of Osaka, Japan and Imperial Chemical Industries to produce acetal copolymers in Japan and Britain respectively under the trade names Duracon and Alkon (later changed to Kematal). In the early 1970s Ultraform GmbH (a joint venture of BASF and Degussa) introduced a copolymer under the name Ultraform and the Japanese company Asahi Chemical a homopolymer under the name Tenal. 

For example, Celanese announced Celcon acetal copolymer in February 1961. By the last half of 1962 and the first half of 1963 we carried through on a specific advertising and promotion program which consisted of ... 

Celanese Plastics Co., Chatham, NJ, The CELCON Acetal Copolymer Design Manual, (undated). 

Stable acetal copolymers of formaldehyde, called Hostoform and Celcon were also produced commercially by the cationic copolymerization of formaldehyde with ethylene oxide — ... 

CELCON Acetal Copolymer Properties, Brochure 10M, Celanese Corp., New York, June 1983. 

ALTERNATIVE NAMES, TRADE NAMES Polyacetal, polyoxymethylene, acetal, Delrin , Celcon (copwlymer), Ultraform (copolymer)... 

Polyacetal can be divided into two basic types, acetal homoploymer and acetal copolymer. Both homopolymer and copolymer are available in a range of molecular weights (M = 20 000-100 000). The homopolymer is a polymer of formaldehyde with a molecular structure of repeated oxymethylene units (Staudinger, 1932). Large-scale production of polyformaldehyde, i.e. polyacetal, commenced in 1958 in the USA (US Patent 2 768 994,1956) (British patent 770 717,1957). Delrin (1959) was the first trade mark for this polymer by Du Pont Company. The copolymers were introduced by the Celanese Corporation of America, and the first commercial product named Celcon (1960). One of the major advantages of copolymerization is to stabilize polyacetal because the homopolymer tends to depolymerize and eliminate formaldehyde. The most important stabilization method is structural modification of the polymer by, for example, copolymerization with cyclic ether. 

Celanese Corp., Ticona Engineering Polymers, Celcon Acetal Copolymer Literatnre, www.Ticona.com, 2006. 

A room-temperature solvent, hexafluoroacetone sesquihydrate, when used at full strength, is a very effective bonding agent for bonding acetal copolymer to itself, to nylon, and to ABS. This solvent is available from the Allied Corporation. Bond strengths (in shear mode) for acetal copolymer to itself and acetal copolymer to nylon >5.86 MPa have been obtained on Celcon to ABS. Hexafluoroacetone sesquihydrate is a severe eye and skin irritant and care should be taken in its use. ... 

Figure 3.27 Stress vs. strain for Celanese Celcon M25—high moiecuiar weight, high toughness, high impact acetal copolymer resin.

Figure 3.35 Stress vs. strain plot for 25% glass-reinforced grade of Celanese Celcon acetal copolymer (ISO 527) [3].

Figure 3.38 Flexural modulus vs. temperature for Celanese Celcon M25/M90/M270 acetal copolymer resins.

Figure 3.49 Typical normalized Celanese Celcon acetal copolymer DMA plot [3].

Figure 3.52 Tensile yield strength vs. temperature for Celanese Celcon M90— medium viscosity, general purpose acetal copolymer resin.

Figure 3.82 Dissipation factor vs. frequency at 23°C for unfilled Celanese Celcon acetal copolymer resin [3].

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