Vacuum lamination process materials

In a vacuum lamination process, the steeper the melt viscosity/temperature curve for sheet pottant material, the better. The layers need to be dry and non-tacky during the initial evacuation step so as not to trap air between them. At the same time, the pottant must then melt to as fluid a state as possible in order to effectively penetrate and wet all the irregularities of the cell circuit. 

Sclairfilm LX. Ideal for use on vacuum packaging equipment for lamination to other materials, such as nylon or polyester films. In converter combinations, LX is particularly suited for the vacuum packaging of processed meats, cheese, coffee, and frozen foods. " ... 

In the vacuum infusion process, the fibre sheets are placed in a dry state with a plastic sheet laid over the entire form to create a vacuum. Resin is introduced at one end. The vacuum enables the flow of the resin and an even distribution of the matrix through the fibres. In comparison with the hand laminating process, a higher volume of fibre can be achieved in the composite material. However, it is difficult to control the flow of the resin along edges, comers, etc. It is also not possible to vacuum-infuse honeycomb materials for a sandwich structure. 

In general, very little data have been published on the outgassing properties of the skins for vacuum panels, even though they can contribute, in some cases, in a non-negligible way to the deterioration of the pressure inside the VIP. This can be due to the outgassing properties of the materials used as barrier layers and/or the lamination process, which may introduce volatile substances or trap gases in between the various sheets. 

Thermoset based composite laminates are generally produced bj Autoclave/Vacuum Degassing Lamination Process (38, 39). The characteristics of this inocess are shown in Fig. IS. In this process, pr eg plies of desired shape are laid up in a prescribed orientation to form a laminate. The laminate is covered with successive layers of an absorbent material (glass bleeder fabric), a fluminated film to prevent sticking, and, finally, with a vacuum bag. The mitire system is placed upon a smooth metal tool surface into an autoclave, vacuum is a Ued to the bag and the temperature is increased at a constant rate in order to promote the resin flow and polymerization. The autoclave process will be used along this section as a case study to describe the influence of the matrix characteristics on the processing behavior of hi performance conqmsites. 

Process of molding or laminating in wliich fluid pressure is applied, usually by means of water, steam, air or vacuum, to a flexible film or bag that transmits the pressure to the material being molded. 

The main difficulty in manufacturing a syntactic foam lies in the choice of the process parameters for mixing the components (temperature, duration, and addition sequence). When the mixture leaves the mixer, its viscosity must be low enough for the mold to be filled rapidly, although once there, the viscosity should rise rapidly to prevent the mixture from becoming laminated. If possible, it is best to mix and pour the materials under vacuum so as to prevent the formation of pores and cavities in the finished material. 

In addition to vacuum-deposited small-molecule structures, bilayer devices have been fabricated from conjugated polymers and other solution-processible materials. One study reports a 1.9% efficient device fabricated by lamination of two spin-coated polymer layers (Granstrom et al, 1998). In principle, polymer bilayers can also be fabricated by spin-coating of successive layers using incompatible solvents. A more practical route to planar bilayers is the deposition of successive layers that have previously been spin-coated and removed from the substrate by a float-off technique (Ramsdale et al, 2002). 

Vacuum lamination of terrestrial photovoltaic modules is a new production process requiring special equipment and a significant material development effort. Equipment design studies resulted in improved control and lower costs when using a double-chamber vacuum laminator. Application testing of new materials and primers showed the feasibility of two different back sheet materials, one encapsulant, two new primers for polymers and one primer for metals. 

Vacuum lamination is an acceptable process for manufacturing void-free PV modules, if matched with correct materials and used with a qualified cure cycle. 

SparPreg , a UD prepreg also for use with thick laminate sections. The excellent breathability of the material produces laminates of exceptional quality with low void content, without the need for debulking or additional dry fabric reinforcement to aid air removal during the application of vacuum and the subsequent curing process. 

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