Flakes, laminated

Blatter erde, /. potassium acetate. Oba. erz, n. foliated tellurium (oagyagite). blatterformig, a. in the form of leaflets or flakes laminated leaf-shaped. 

Some common flake-shaped LCMs consist of shredded cellophane and paper, mica (qv), rice hulls, cottonseed hulls, or laminated plastic. These materials He flat across the opening to be sealed or are wedged into an opening such as a fracture. Some are sufficiently strong to withstand considerable differential pressure, whereas others are weak and the seal may be broken easily. Weaker flake materials typically are used near the surface or in combination with fibrous or granular additives. 

It has been demonstrated that red oak OSL could be used to replace 35% to 40% of the phenol (or phenolic resin solids) in phenol-formaldehyde resins used to laminate maple wood and to bond southern pine flake boards (wafer-board and/or strandboard) without adversely affecting the physical bond properties. While this pulping process and by-product lignin do not commercially exist at this time in the United States, lignins from such processes are projected to cost 40% to 50% less than phenol as a polymer raw material. 

The success obtained in this study on bonding flake board and maple blocks supports the possibility of using OSL in resins for bonding crosswise laminates (i.e., plywood). Subsequent research conducted at the Mississippi Forest Products Utilization Laboratory on OSL-PF resins for bonding plywood has been equally successful. 

Resin Preparation. Two approaches to resin preparation were used with regard to the initial stages of condensation, depending on whether the resin was intended for laminating maple blocks or for bonding southern pine flake boards. For maple block resins, the steps involved were as follows addition of water, sodium hydroxide (optional) and lignin, which were heated and... 

To obtain ballistite with a more progressive rate of burning, attempts were made to produce laminated flakes, with the two outer layers made of attenuated ballistite and an inner one, sandwiched between, made of ordinary ballistite. In the attenuated ballistite DNT was substituted for part of the nitroglycerine. However a powder of this type retained its ballistic characteristics for only a few months, since, due to diffusion, the composition of all three layers gradually became equal. 

This method consists of high-frequency sound waves (0.1-25 MHz) incident upon the test sample and measuring the energy of the reflected beam. Because of the flaws in the sample there will be loss in energy of the beam, known as attenuation. Cracks, laminations, shrinkage cavities, bursts, flakes, disbonds and other discontinuities can be detected by this method. 

Dlsparlure has also been used in mating disruption experiments since the early 1970 s and many of these experiments have demonstrated that mating of tethered females could be reduced by 90% or better in plots treated with controlled-release formulations of 20-50 g of racemic lure per hectare (12). One successful dlsparlure formulation for aerial application has been the laminate dispenser chopped into small flakes and coated with adhesive a special apparatus has been described for the application of these flakes (see later chapters in this symposium by Plimmer et al. and Kydoneieus et al.). Based on the release data obtained with dispensers, the small flakes, which have a high amount of perimeter or edge relative to their surface area, whould be expected to lose lure at a faster rate than larger dispensers made of the same laminate. 

For 1980 tests In Maryland, an effort was made to release a greater amount of the lure during the peak flight period of the insect by reducing the size of the flakes. The laminate (again 3-mll vinyl film) was chopped Into 2.4 x 2.4 mm squares (5.7 mm ). The two, as measured from the lure contents of recovered flakes, had only dropped to 53 days. 

Since a still shorter t, was desired, the size of the flakes was reduced to 1.9 mm (0.8 x 2.4 mm) for the 1981 tests In Wisconsin and Michigan the 3-mil vinyl film was again used as the top and bottom layers of the laminate. The analysis of recovered flakes gave t /o values of 38 days in Wisconsin and 46 days in Michigan this release seems ample for the program needs, especially when one considers that the release from these flakes would be somewhat faster at the warmer temperatures encountered in Eastern states such as Maryland. 

The first plot received 500 g.a.i./h of displarlure as NCR gelatin-walled microcapsules containing 2% ai. The formulation, applied as an aqueous suspension, also contained 1 of sticker to aid adhesion of the formulation to foliage. The second plot received 500 g./h. as Herculite Corporation sprayable laminate flakes containing 9.1 ai. The flakes consisted of two layers of vinyl, each 0.08 mm thick on both sides of a central porous layer containing the disparlure the surface area of the flakes was between 7 and 35 mm2 per side. The same sticker as that in the microcapsules was used. The third plot received 330 g.a.i./h as "Conrel" controlled release hollow fibers containing nominally 11.5% ai. a suitable sticker was also incorporated in the formulation. (Note that the use of trade or proprietary names here or elsewhere does not constitute an endorsement by the USDA). 

The behavior of two other formulations, microcapsules and small plastic laminate flakes, containing tetradecenol formate, were compared in applictions to plots of mature corn at Beltsville, in August 1980. (8) The Z-9-tetradecen-1-ol formate (TDF) is a mating disruptant, rather than a true pheromone, of the Heliothis species of moths. It was selected in these experiments because reliable analytical methods were available (9) and its behavior was expected to be similar to that of the actual pheromones, whose chemical structures and properties are also similar. The two formulations were polyurea-polyamide microcapsules 5-microns in diameter supplied by ICI at Bracknell, Berkshire, England, and a small (3 mm side) plastic laminate formulation supplied by the Herculite Corporation of York, PA. The microcapsules were applied at 300 g of TDF per hectare and the flakes at 285 g/h. Both formulations were applied by air to mature corn 240-270 cm in height in clear, hot weather with a daily maximum temperature of 39°C. 

Persistence The results presented in Figure 2 show that the TDF residues disappeared from the laminates substantially faster than from the microcapsules. Expressed in terms of first-order kinetics the half-life in the capsules was 13-5 days and 5.3 days in the laminates. The latter figure agrees well with laboratory measurements of release rates these also suggest that, in this formulation, the loss rate is controlled by diffusion outward to the edges of the flakes rather than through the exterior layers of vinyl covering. 

Figure 2. Decrease in residues of Z-9-tetradecenol formate in microcapsules (-------) and laminated flakes (----) after field application to mature com (8).

Figure 7. shows the results of a field test of formulation A. The plastic laminated flakes were applied at a very high rate (500 g A.I./ha) on June 29th, 1980 to a mixed spruce/fir stand near Machias, Maine. The two curves represent mid-day (12 00 - 14 00) canopy concentrations of TDAL as well as the temperatures at that time. A period of heavy rain spanning July 1st and 2nd is reflected both in low noon temperatures and low aldehyde concentrations. 

The racemic form is as effective as the (+) enantiomer for disrupting mating. This technique for population suppression has been evaluated in experiments to compare the effects of formulation, dose rate and population density on its efficacy. In light infestations, gypsy moth mating is effectively suppressed. Microcapsules, laminated polymeric "flakes" and hollow fibers were compared as controlled-release formulations. 

Hereon Disrupt, a formulation of polymeric 3-layer laminated flakes ca 3 mm x 3 mm containing racemic disparlure (20 mg/in ) (Health-Chem Corp., New York,... 

In a 1981 study on western pine shoot borer, three sets of traps baited with synthetic pheromone in controlled release PVC (polyvinyl chloride) pellets (12) were placed in ponderosa pine plantations (16 or more ha in size), treated with (a) Health Chemicals Hereon laminated flakes at some 20,000 flakes/ha with a pheromone release capacity of 10 g/ha/season (b) strips of Hereon laminated plastic (30 x 2 cm) at 25 strips/ha stapled on trees at 20 m intervals with a pheromone release capacity of 5 g/ha/season and, (c) an untreated check plot. The Pherocon II adhesive traps were baited with PVC pellets at five different bait strengths of 0.001%, 0.01%, 0.1%, 1.0%, and 10% pheromone by weight. Each of these baits was replicated seven times in each disruption treatment for a total of 35 traps per plantation and 105 overall. The traps were placed in lines of five with each bait concentration represented once in each line. The positions of the traps were randomized by bait concentration within each line, and traps were spaced at least 20 m apart. All traps were left in place through 4-weeks of the shoot borer s seasonal flight. 

From time to time PLASTEC specialists publish technical reports and notes on information felt to be of interest to the technical community. These reports are sold by NTIS, located at 5285 Port Royal Road, Springfield, Virginia 22161 at a price commensurate with their handling and printing cost. A selected list of PLASTEC reports and notes is given under Refs Refs 1) A.M. Shibley, State of the Art, Flake-Glass Laminates , PLASTEC Rept 1 (1960)... 

It is impossible to achieve a dft between 400-500 xm in two coats without fibre glass reinforcement. In some laminate systems, glass flakes are also used as fillers. Their function is to minimise the shrinkage stress. 

Polyester coatings are suitable for concrete and steel substrates. The systems are generally used as laminates in conjunction with the use of glass cloth or glass flakes as the reinforcement. Polyester coatings are particularly useful in areas where resistance to mineral acids is required. Typical properties of polyester coatings are given in Table 9.2. 

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