Scrim cloth

The viscosity of epoxy resins and curing agents can be used to control the bond line thickness within the adhesive joint. But the bond line can also be regulated by the incorporation of fillers, by the use of scrim cloth or woven tapes as internal shims within the adhesive itself, or by the careful regulation of the cure cycle. 

Nonwovens The textile and paper industries are based on the two oldest (wet and dry) processes. Manufacturers of nonwovens for plastics draw on both. With the wet, there are basically two types namely the Fourdrinier and cylinder machine types that have been modified. In addition, two basic types exist for the process formation of the web and application of the bonding agent or system where mechanical carding of fibers is used. The particular equipment and method of operation to be used, with their many modifications, is influenced by desired requirements such as mechanical properties, softness, surface condition, tenacity, etc. There are certain t) es of so-called nonwoven fabric that are directly formed from short or chopped fiber as well as continuous filaments. They are produced by loosely compressing together fibers, yarns, rovings, etc. with or without a scrim cloth carrier assembled by mechanical, chemical, thermal, or solvent methods. Products of this type include melted and spun-bonded fabrics. 

Bonding of the skins is done in several ways. In one technique, an epoxy cement or cement-impregnated scrim cloth is used to bond already cured facings or aluminum skins to the core. In another technique, noncured resin-impregnated and catalyzed skins are simply laid up on the core stock and cured, usually with a vacuum bag to furnish pressure. B-staged fabrics are often used for these apphcations. 

A scrim cloth can also be used in adhesive bonding as a automatic means of retaining a certain adhesive thickness. In this process, the scrim is used as a cloth spacer, impregnated with adhesive. The glass fibers in the scrim cloth act as shims to separate the two adherends regardless of the amount of pressure placed on the joint. 

As with tissue, woven glass cloth is used for decorative or acoustic purposes. Additionally, close-woven fabrics give improved fire-safety properties and are resistant to mechanical abuse. Glass cloth or scrim of an extremely open weave is used on insulants as a key for mastic or hard-setting finishes. 

There are also other products produced such as foamed vinyl fabrics (Chapter 8). One method of fabrication is to coat a thin layer of solid plastisol on embossed release paper, then coating a thicker coating of foam plastisol and finally layering on a cloth scrim. The composite is... 

In the majority of cases they are produced by needle punching a batt of fibres (a number of layers of carded fibre web formed by means of a cross-laying mechanism) on to both sides of a woven base-cloth or scrim. This may be carried out in a continuous process or by attachment of a preformed and pre-needled batt produced in a separate operation. After tacking the fibre to the scrim, the assembly is consolidated in a secondary, more intensive needle-punching operation, usually with the aid of finer needles. This operation frequently addresses both sides of the felt simultaneously in a single double-punch process. 

The use of a woven scrim, whilst not employed in every case, provides the non-woven with stability and the necessary tensile characteristics in order to withstand the stresses imposed by the predominantly pulse cleaning mechanism, whereas the batt provides the necessary filtration efficiency and also a measure of protection for the base cloth from abrasion caused by constant flexing against the cage wires. Depending on the tensile specification of the finished nonwoven, the area density of scrims is usually in the range of 50-150 gm". ... 

Where the filter medium is in the form of a needle felt (as found in pulse-jet collectors), some manufacturers have offset the deficiencies found in some of the above fibres by producing composite structures, e.g. polyar-amid, polyimide or PPS fibres on the surface of the felt with a PTFE scrim or base-cloth providing a framework of support. Although under certain physicochemical conditions the surface fibres become degraded, it has been found that the skeleton of support provided by the PTFE base-cloth is often sufficient to enable satisfactory performance to continue. 

Fabrics, hessian, sacking, scrim, carpet backing cloth and canvas. 

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