Ply adhesion

Ply adhesion - The force required to separate two adjoining plies in a specified width of a rubber product. 

Table I. Ply Adhesion for Test Samples Glued with Hemicellulose Corrugated Board Adhesive (15% Solids)...

Entry NaOH1 Borax1 Ply Adhesion N/m Ave. Minimum Coeff. Var. (%) Double Backer Fail (%)... 

Ply Adhesion of Soda Bagasse Hemicellulose. First, various hemicellulose mixtures were evaluated solely on a ply adhesion basis. A suspension (15% solids) of hemicellulose, of a particle size below 0.2 mm, was prepared at ambient... 

The results listed in Table I indicate that the ply adhesion of the hemicellulose adhesive increased with increasing amounts of borax and sodium hydroxide. The increase in strength, however, leveled off after an optimum was reached. Optimum strength results were obtained with 3.8% borax and 1.3% NaOH on hemicellulose solids. These quantities of additives were subsequently used in all further experiments. 

Samples were glued and tested for ply adhesion at different solids contents of the adhesives. These results are illustrated in Figure 3. All the adhesives tested gave 100% fiber failure for all the consistencies tested. 

The ply adhesion values of test samples glued with the suspended hemicellulose adhesive leveled off at consistencies above 16% solids. The strength of this adhesive above 16% solids was similar to the strength values of industrial corrugated board samples. The industrial board was collected from the mill that supplied the single-faced and liner material. 

The ply adhesion of the dissolved hemicellulose adhesive was high at low solids content but decreased somewhat at higher solids contents (Figure 3). The set time of this adhesive was, however, long at low consistencies. 

The stability of the hemicellulose adiiesives and the effect of particle size were subsequently assessed. Hemicellulose adhesives were prepared with a portion (one-sixth) cooked and the remainder raw with borax and sodium hydroxide as before. Different particle sizes of hemicellulose were used for the suspended portion. The mixtures were used to glue corrugated board test samples after 4 hours or 4 days standing. The results (also on citrus box material) shown in Table III clearly indicate that the ply adhesion strength of the adhesives was not affected by standing or by particle size. 

Gel Properties. The ply adhesion results so far indicate a good potential for bagasse hemicellulose as an adhesive for corrugated board. The industrial... 

Table II. Ply Adhesion of Hemicellulose-Bonded Corrugated Test Samples (Citrus Box) Employing Different Quantities of Hemicellulose...

Entry Adhesive Thickness Approximate Adhesive Uptake Ply Adhesion Average Coeff. Var. Set Time... 

The studies on the ply adhesion of the hemicellulose adhesive showed that the addition of 2 to 3% of borax on hemicellulose led to substantial improvements in the strength of the adhesive. A hemicellulose solution was subsequently prepared containing 2% borax (on hemicellulose) at pH 8.5. The solution was... 

Soda bagasse hemicellulose gave acceptable ply adhesion of corrugated board when evaluated by a laboratory application procedure. The gel properties of the... 

Chem. Descrip. Aliphatic waterborne PU coating Uses Coating for nylon and polyester syn. threads and narrow web, improving slip, antiwicking and ply adhesion Features Contains heat reactive crosslinker... 

Reasonably attractive properties were also observed with ethylene oxide-propylene oxide copolymers. A blend of 53 percent Union Carbide UCON 75-H fluids 380,000 (molecular weight 21,000 75 percent ethylene oxide) in MCEA was irradiated for 9 sec. and found to have peels of 3.5 pli (adhesive failure) and shears of 31 hours. 

MCEA was found to develop a modest pressure-sensitive adhesive when photocured for 9 sec. (0.4 pli, adhesive failure/40 min. shear). 

Surface quality Sometimes, specific requirements apply to certain parts of the composite structure with respect to surface quality, e g. regarding aerodynamics or hydrodynamics, visnal appearance or fnnctional interfaces. In such cases, good surface quality of the mould is required. Also, the characteristics of the mould surface will determine the ease of first ply adhesion (see below). 

Delamination Insufficient ply-to-ply adhesion (due to contamination or insufficient tack) damage due to rapid cool-down from cure temperature Deteriorated mechanical strength and durability... 

A final use of adhesives for composite structure is as a surfacing ply. In this application a low flow adhesive is applied to the composite surface prior to cure in order to produce a cosmetically smooth surface that is ready for painting without further finishing operations. In addition, surfacing ply adhesives as well as interleaf films have been effective in reducing the porosity of composite skins. This has led to their applications in wet wings to prevent fuel leakage and in composite skin sandwich structure to prevent moisture penetration. 

GM15 Determination of Ply Adhesion of Reinforced Geomembranes D6636... 

Stearic acid has a double function in Thiokol compounds. The first benefit is as in internal lubricant to improve null release and also to aid in releasing from the mold after vulcanization. Note that 0.5 phr is normal for most compounds however, if good tack and ply to ply adhesion is needed, such as for rollers, the level may be reduced to 0.25 phr. The second function of the stearic acid is to aid in the dispersion of fillers and to activate the cure system for a tighter state of cure. 

Calendering of Thiokol FA compounds is best accomplished with the top roll at 42°C and the middle one at 39 C, and the maximum thickness set at 0.08 cm. The feedstock should be well warmed, fed in small strips, and a small rolling bank be maintained. If the compound is to be plied up to obtain a greater thickness, then the compound will need to have tackifiers included for satisfactory ply adhesion. 

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