Thermoplastics sealants

Thermoplastic sealants are, in general, either preformed sealants or hot-applied polymeric sealants. 

The lower molecular weight PCTFE oils, waxes, and greases are used as inert sealants and lubricants for equipment handling oxygen and other oxidative or corrosive media. Other uses include gyroscope flotation fluids and plasticizers for thermoplastics. 

Hydrocarbon resin is a broad term that is usually used to describe a low molecular weight thermoplastic polymer synthesized via the thermal or catalytic polymerization of coal-tar fractions, cracked petroleum distillates, terpenes, or pure olefinic monomers. These resins are used extensively as modifiers in the hot melt and pressure sensitive adhesive industries. They are also used in numerous other appHcations such as sealants, printing inks, paints, plastics, road marking, carpet backing, flooring, and oil field appHcations. They are rarely used alone. 

In the adhesives area, thermoplastic, fatty polyamides are used in hot-melt and heat-seal adhesives for leather, paper, plastic and metal. Blends of EDA- and DETA-based polyamides are suggested for use in metal can seam sealants with improved toughness (234) pressure sensitive adhesives have been formulated with DETA-based polyamides (235) and anionic and cationic suspensoid adhesives are used as heat-seal coatings in paper converting (236). PIP and certain PIP derivatives are used with EDA in some appHcations (237). 

Polyisobutylene is produced ia a range of mol wts, and has found a host of uses. The low mol wt Hquid polybutenes have appHcations as adhesives, sealants, coatings, lubricants, and plasticizers, and for the impregnation of electrical cables (7). Moderate mol wt polyisobutylene was one of the first viscosity-iadex modifiers for lubricants (8). High mol wt polyisobutylene is used to make uncured mbbery compounds, and as an impact additive for thermoplastics. 

The market is dominated by flexible foam applications (43% in the United States) and rigid and semi-rigid foam (29%). Cast elastomers (4%) and RIM elastomers (3%) have only specialised outlets. The remaining sizeable 21% of the market cover such diverse uses as thermoplastic rubbers, surface coatings, adhesives, sealants and synthetic leathers. 

Organic polymers are sometimes referred to as plastics (although, this should be confined to thermoplastic polymers), macromolecules or resins, though the latter is often used to describe raw polymeric material awaiting fabrication. Many polymers are used in various forms that are not associated with normal plastic materials. These include paints and coatings, elastomers (rubbers), adhesives, sealants (caulks), surfactants and also their use in various industrial applications, e.g., ion-exchange resins, membranes. 

Sealants - [ELASTOMERSSYNTHETIC - POLYISOPRENE] (Vol 9) - [SEALANTS] (Vol 21) -acrylics [ACRYLICESTERPOLYMERS - SURVEY] (Voll) -barium compds in [BARIUM COMPOUNDS] (Vol 3) -based on liquid polysulfides [POLYMERS CONTAINING SULFUR - POLYSULFIDES] (Vol 19) -defoamersin [DEFOAMERS] (Vol 7) -fiom fluorosilicones [FLUORINE COMPOUNDS,ORGANIC - POLY(FLUOROSILICONES)] (Volll) -hydrocarbon resins in [HYDROCARBON RESINS] (Vol 13) -lecithin in (LECITHIN] (Vol 15) -organolithiumcmpdsinprdnof [LITHIUM AND LITHIUM COMPOUNDS] (Vol 15) -polysulfide curing [PEROXIDES AND PEROXIDE COMPOUNDS - INORGANIC PEROXIDES] (Vol 18) -propylene oxide in mfg of [PROPYLENE OXIDE] (Vol 20) -PVB m [VINYL POLYMERS - VINYL ACETAL POLYMERS] (Vol 24) -rheological measurements [RHEOLOGICAL MEASUREMENTS] (Vol 21) -from styrenic block copolymers [ELASTOMERS SYNTHETIC - THERMOPLASTIC ELASTOMERS] (Vol 9) -use of dispersants [DISPERSANTS] (Vol 8)... 

Bulyk. Butyl-based materials are sold in the form of preformed tapes, thermoplastic hot melts, and one-part solvent-releasing sealants. Butyl polymers are made by the copolymerization of 97-98 mol % isobutylene with 2-3% isoprene. Another butyl-based polymer, polyisobutylene, is produced by the polymerization of isobutylene. Formulations of butyl-based sealants also include plasticizer, filler, and lackifier resins. Poly butenes are common plasticizers for butyl sealants. Solvents, such as mineral spirits, are used for the one-part solvent-releasing formulations. As the solvent leaves the typical one-part butyl, the sealant hardens and loses its elastomeric ability. This limits the use of solvents to low movement applications where durability is not of high concern. 

Several organic sealants such as epoxy resins, butyl rubber or silicones prove to be more or less permeable and the tiny amount of solvent in the cell is rapidly lost. Suitable organic sealing materials for this technology turn out to be thermoplastic materials, like polyethylene/carboxylate copolymers. So far, Surlyn 1702 ionomer from Dupont has been the main substance used to optimize cell performance and build module prototypes. However, the softening point of Surlyn is rather low (65° C) and at elevated temperatures (> 70°C), serious solvent loss is observed because the bond between Surlyn and TCO-coated glass is substantially weakened [7]. 

Polysulfide resins combine with epoxy resins to provide adhesives and sealants with excellent flexibility and chemical resistance. These adhesives bond well to many different substrates. Tensile shear strength and elevated-temperature properties are low. However, resistance to peel forces and low temperatures is very good. Epoxy polysulfides have good adhesive properties down to -100°C, and they stay flexible to -65°C. The maximum service temperature is about 50 to 85°C depending on the epoxy concentration in the formulation. Temperature resistance increases with the epoxy content of the system. Resistance to solvents, oil and grease, and exterior weathering and aging is superior to that of most thermoplastic elastomers. 

Sometimes primers can take the place of surface treatments. Two examples are with porous substrates and with certain plastic substrates. With weak porous substrates, such as wood, cement, or porous stone, the primer can be formulated to penetrate and bind weakly adhering material to provide a new, tightly anchored surface for the adhesive. Chlorinated polyolefin primers will increase the adhesion of coatings and adhesives to polypropylene and to thermoplastic olefins. The chlorine atoms in the outer surface of the primer increase surface energy and enhance adhesion of adhesives, sealants, and paints. 

Medium and high molar mass polyisobutenes are used essentially as basic materials for sealants and adhesives, as flexibility improvers for waxes and bitumen and as impact additives for thermoplastics. The low toxicity allows their use in chewing gum formulations. Detailed production is not disclosed but it is probably limited to a few tenths of kilotons. Main producers are BASF (Oppanol Bl-3, B10-50, B80-246) and Exxon Chemical (Parapol, Vistanex LM and MM). 

Adhesives and sealants were some of the first products to be made from block polymer thermoplastic elastomers and remain among the most important... 

Solvent-based acrylic sealants are semi-elastomeric because of their thermoplastic nature. The movement accommodation factor is approximately 20%. However, these sealants perform best in the area from 7.5%... 

MAJOR PRODUCT APPLICATIONS exterior paints, coatings, synthetic plastering compounds, thermoplastic road marking compounds, adhesives, sealants, plastics, abrasives, cables, stucco, kitchen sinks and laminates, dental, mihtary, electronics... 

Hotmelt adhesives are thermoplastics that are processed free of solvents in the melted state and are therefore known as hotmelts. Since the adhesives are 100% solids, no volatile components can be released. No incineration and/or ventilation systems are required to dispose of the solvents. These adhesives are used to fill larger gaps and therefore often function as both adhesives and sealants. Foamed hotmelt adhesives comprise a special category They are capable of filling large gaps with very little material while still bonding the substrates. 

Based on the numbers in Figures 1 and 2, by 1985 RIM and RRIM will require approximately 50 M lbs. of monomeric MDI, which is about one-third of the monomeric MDI supply in 1985 (Table IX based on 20-25% of 85% nameplate capacity, excluding ARCO capacity, = 137-171 M lbs. monomeric MDI). This will leave about 100 M lbs. of monomeric MDI for cast elastomers, thermoplastic polyurethanes, shoe soles, semi-rigid foams, and some adhesives and sealants, a monomeric MDI supply which should be more than sufficient for these applications. As RRIM grows, a need for capacity expansion can be seen in the late 1980 s. No effects on the market will be seen from PUR-SMC until after 1985, and at the present time meaningful projections are impossible. 

Adhesives and sealants, foundry core binders, Spandex fibers, thermoplastic polyurethanes. 

Adhesives and sealants, cast elastomers, microcdWar products, polyurethane stretch fibers (Spandex fibers i, surface coatings, thermoplastic elastomers and Billable gums—... 

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