Liquid Injection Molding
"Liquid injection moldingis an industrial fabrication method that molds stock materials into a range of components and products. It differs from the standard reaction injection molding process in that it relies on mechanical mixing rather than pressurized impingement mixing, and it focuses specifically on liquid silicone rubber and similar elastomeric materials. It is capable of efficiently producing a large number of versatile items, including seals, o-rings, isolators, and electronic contacts."
Thomas Net 12/4/2010
"Typical liquid injection molding processes include the use of high temperature and/or high pressure liquid injection. The molding process and molding device requires use of both an elevated pressure of 24,500 kPa (3,500 psig) and an elevated temperature of 250.degree. C. (480.degree. F.). Upper and lower molds are mated to one to define a mold cavity therebetween. Liquid gasket material, such as epoxy resin or plastic rubber, is pumped into a mold cavity at 2,900 kPa (430 psig). The molds and the gasket material are heated to about 250.degree. C. (480.degree. F.). The gasket material in pumped into the mold cavity. The molds are then clamped together at the elevated pressure of 24,500 kPa (3,500 psig). After the gasket material is cured, the molds and the gasket are cooled to room temperature. The process is described as requiring about one minute to inject and cure the gasket material. The use of such elevated pressures and temperatures at such short cycle times, however, require the use of metallic molds that can withstand such large fluctuations in pressure and temperature."
(Lim et al of the Henkel Corporation, US Patent 7,790,094, 9/7/2010)
Recent US Patents
9/7/2010
7,790,094
Injection molding process, apparatus and material for forming cured-in-place gaskets
Lim et al of the Henkel Corporation has developed a cured-in-place gasket by liquid injection molding. A radiation curable (meth)acrylate-functionalized poly(meth)acrylate is injected into the mold at 65 C or less and 150 PSI. The curing radiation is conducted into the mold by fiber optics. (RDC 11/29/2010)
Recent Journal Articles
10/29/2010
Closed form solution of resin flow from multiple line gates in liquid composite molding
(pages 1434–1441)Polymer Composites 31 #8 (2010)
Markicevic et al showed that two distinct sub-regions of the porous medium exist: inner sub-region which is filled by the liquid from the manifold, and outer sub-region that is filled by fluid from the channel. An analytical model predicts the interface between the two sub-regions which is called the inner sub-region thickness. Comparisons between experimental and analytical results reveal an excellent agreement for various sets of geometric parameters. (RDC 12/15/2010)