The term "inverse emulsion" is misleading, suggesting incorrectly that Note 5: A w/o emulsion is sometimes called an inverse emulsion. Phase is water or an aqueous solution and the continuous phase is an Water or an aqueous solution and is termed water/oil (w/o) if the dispersed Note 4: An emulsion is termed an oil/water (o/w) emulsion if theĭispersed phase is an organic material and the continuous phase is May exceed the usual size limits for colloidal particles. Usually range from approximately 10 nm to 100 μm i.e., the droplets Note 3: The diameters of the droplets constituting the dispersed phase Note 2: The droplets may be amorphous, liquid-crystalline, or any Note 1: The definition is based on the definition in ref. Appearance and properties Ī fluid system in which liquid droplets are dispersed in a liquid. The word "emulsion" comes from the Latin emulgere "to milk out", from ex "out" + mulgere "to milk", as milk is an emulsion of fat and water, along with other components, including colloidal casein micelles (a type of secreted biomolecular condensate). Nuclear emulsions are similar to photographic emulsions, except that they are used in particle physics to detect high-energy elementary particles. Such a photographic emulsion consists of silver halide colloidal particles dispersed in a gelatin matrix. The term "emulsion" is also used to refer to the photo-sensitive side of photographic film. The droplets dispersed in the continuous phase (sometimes referred to as the "dispersion medium") are usually assumed to be statistically distributed to produce roughly spherical droplets. Įmulsions, being liquids, do not exhibit a static internal structure. Multiple emulsions are also possible, including a "water-in-oil-in-water" emulsion and an "oil-in-water-in-oil" emulsion. Second, they can form a water-in-oil emulsion, in which water is the dispersed phase and oil is the continuous phase. As an example, oil and water can form, first, an oil-in-water emulsion, in which the oil is the dispersed phase, and water is the continuous phase. Two liquids can form different types of emulsions. Examples of emulsions include vinaigrettes, homogenized milk, liquid biomolecular condensates, and some cutting fluids for metal working. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase).
Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids. Emulsions are part of a more general class of two-phase systems of matter called colloids. The surfactant (outline around particles) positions itself on the interfaces between Phase II and Phase I, stabilizing the emulsionĪn emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation.The unstable emulsion progressively separates.
An emulsion of Phase II dispersed in Phase I.Two immiscible liquids, not yet emulsified.You can measure your lamp with two exposures using a Stouffer 21 Step Scale to measure the stencil hardness, then refine your exposure with an exposure calculator. These estimated time charts are based on known commercial screen printing UV light sources on 305 mesh. Start by checking the suggested exposure time on the product Technical Data Sheet. When the stencil doesn't hold in the mesh, it didn't get enough exposure. Screen makers can only expose one side of the stencil, so it is important for the UV energy to move through the stencil, all the way to the back, where the squeegee blade will rub the stencil where it is weakest. You block UV energy with a positive during exposure so the image area dissolves when you develop the stencil with water. Invisible UV energy reacts with emulsion sensitizer and hardens the stencil so it won't dissolve with water and rinse down the drain.
ORANGE EMULSION HOW TO
It is the primary job of the screen maker to learn how to judge exposure.
0 kommentar(er)
