Sealants preformed

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

Preformed sealants are pre-moulded from a range of materials (synthetic rubber, PVC) with different shapes (in tape, ribbons, beads, or extruded shapes), and are mainly used for glazing. 

Figure 97 Roll of preformed sealant tapes and some sections and shapes available on...

Paterson, D. A., XL Butyl Rubber Improves Preformed Sealant Tapes, Adhesives Age, 25 (Aug. 1969). 

XL Butyl in Preformed Sealant Tape, Polysar Technical Bulletin. 

Sealants. Gaskets, and Beads. All gaskets or beads are required to be at least 3/8 inch wide with a Shore "A" durometer hardness of 50 and conform to ASTM Specification C509-84 (Cellular Elastomeric Preformed Gasket and Sealing Material). 

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. 

Test Method for Adhesion in Peel of Elastomeric Joint Sealants Recommended Practice for Surface Preparation of Concrete for Application of Chemical Resistance Resin Monolithic Surfaces Method of Testing Release Papers Used with Preformed Tape Sealants Test Method for T-Peel Strength of Hot Applied Sealants Test Method for Tensile Adhesive Strength of Preformed Tape Sealants by Disk Method... 

Intumescent sealants are widely used in expansion and compression joints, construction gaps, fire protection panels, fire doors and around cable and pipe penetration. They work with, or replace, fire stops and preformed seals in the creation of compartments which are essential to efficient fire protection. 

Outgasslng of Silicone Polymers. The percent condensable versus time curves at 150°C for the heat vulcanized (HV) preformed silicone seals, and for the room temperature vulcanized (RTV) silicone sealants are shown in Figure 2. Samples of each class of silicone were obtained from several sources for evaluation in this study. For ease of discussion, however, only the high and low extremes for each class of silicone are plotted in Figure 2. All of the other silicones evaluated fell between these extremes. 

ASTM C772-97 Standard Test Method for Oil Migration or Plasticizer Bleed-Out of Preformed T e Sealants... 

ASTM C1281-99 Standard Specification for Preformed T e Sealants for Glazing Applications... 

Apart from the poured joint sealants, particularly for the expansion type of joints, there are also preformed joint seals that are placed after compressing them into the expansion joint. These materials are such that they are always compressed, even when there is a complete expansion of the joint. The preformed joint seals should comply with specifications such as CEN EN 14188-3 (2006), ASTM D 2628 (2011), ASTM 1752 (2013), AASHTO T 42 (2010), AASHTO M 33 (2012), AASHTO M 153 (2011) or AASHTO M 213 (2010). 

CEN EN 14188-3. 2006. Joint fillers and sealants - Fart 3 Specifications for preformed joint seals. Brussels CEN. 

Sealant materials could be hot applied (complying with CEN EN 14188-1 2004 or ASTM D 6690 2012), cold applied (complying with CEN EN 14188-2 2004 or ASTM D 5893 2010) or preformed joint seal material applied by compression (complying with CEN EN 14188-3 2006, ASTM D 2628 2011 or other specifications). When backer material is used, it should comply with ASTM D 5249 (2010) or any other specification. 

Gasketing materials are generally preformed elastomers that are available as o-rings, rope, and other convenient shapes. Gaskets may also be cut from stock material such as thin sheet. However, sealants can be used to make formed-in-place gaskets. A ribbon of uncured sealant is applied to the flange area of the components to be sealed. On assembly of the components, the sealant is compressed to conform exactly to the mating surfaces. 

Coating/dispensing Brush, trowel Spraying, extrusion Roll application (manual or automatic) Hot melt equipment Stencil, dip coating Film adhesives Pressure sensitive adhesives Preformed adhesives and sealants (in solid form)... 

In the last 40 years, many suppliers tried to find methods of clean and easy application of adhesives, glues and sealants. The main idea was to use adhesives in dry form, to avoid the stickiness and dirty application of the old glues. A need for adapted application equipment came from this. The main invention was the pressure sensitive tapes and labels, and then the hot melts supplied as dry solid granulates. There was also the preformed tape sealants, the structural adhesives supplied as film adhesives used in aircraft bonding figure 92, the heat sealable tapes and films, the hot melt sticks and lately the glue sticks for office use. 

Dry adhesives and sealants may be supplied as preformed tapes or ribbons, for instance butyl, acrylic or oleoresinous sealants. They are supplied in rolls and various sections or shapes (Fig. 91) and the surface is protected by a release paper (siliconised paper). 

A Vs-in. thick preformed plain elastomeric pad or fabric pad placed atop the concrete bearing surface or grout pad most economically compensates for any minor surface irregularities. Fully threaded anchor rods can be either cast into the concrete or drilled and grouted into place. An anchor plate can be either bolted or welded to the bottom of the anchor rod to augment uplift capacity in the concrete. If no uplift capacity is required, a swedged rod may be substituted for a threaded one. The swedged rod may be terminated just below the top of the masonry plate and the void filled with a flexible sealant. 

Caulks and sealants made from the isobutylene polymer family are available in three forms. As bulk sealant materials, they are usually one-part, plasticized systems, compounded with suitable inert fillers and solvents and designed for application with a standard caulking gun. As preformed tapes or ribbon sealers, they are 100% solids, tacky materials, supplied in roll form on a release paper backing and designed for easy hand application in areas which usually require compressive confinement for an effective seal. Finally, in a newer format as 100% solids, hot melt compositions, they are specif-... 

Sealing Tapes.The 100% solids, preformed tape sealants, because of their form and ease of handling, provide economies in installation often unattainable with other sealants. Tape rolls are available in a variety of widths and thickness and many times contain an embedded string or cured rubber core to prevent stretching or drawdown in use. All tapes have some degree of pressure sensitivity and are sufficiently soft to allow for ease of compression during installation. 

Other insulated glass sealants are designed as hot melt compounds with regular or partially cured butyl as the base. These compounds are either hot pumped into place or are applied in a thermoplastic, preformed tape construction. 

Extruded Tapes. These are preformed ribbons or profiles of butyl rubber, neoprene, or polyvinyl chloride, and may be either solid or expanded. They may be supplied as composite structures with rubber cores, rubber rod spacer, or aluminum shims surrounded or embedded in an adhesive or sealant. 

Strip Sealants—Hot-Applied Preformed Strips. These sealants are also supplied with backing paper. The backing paper is removed from a suitable length of strip sealant and fit into the slot to be sealed. The strip is then heated to the manufacturer s recommended temperature. Caution must be taken that the heat-softened material achieves continuous... 

Compression Seals. These are preformed cellular elastomeric products available in either precompressed or uncompressed forms. The sealant may utilize external and/or internal adhesive elements. The seal is obtained by placing the preformed material in compression between the joining surfaces. Exact storage, handling, and application instructions must be followed. 

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