| 词条 | Expandable microsphere |
| 释义 |
Expandable microspheres are microscopic spheres comprising a thermoplastic shell encapsulating a low boiling point liquid hydrocarbon. When heated to a temperature high enough to soften the thermoplastic shell, the increasing pressure of the hydrocarbon will cause the microsphere to expand.[1] The volume can increase by 60 to 80 times. Expandable microsphereThe expandable microsphere is a material that can act as a blowing agent when mixed in a product and subsequently heated to cause expansion within the matrix. The expandable microspheres are off-white, can be 6 to 40 micrometers in average diameter and have a density of 900 to 1400 kg/m³. The expandable microspheres are used as a blowing agent in products like e.g. puff ink,[2] automotive underbody coatings or injection molding of thermoplastics.[3] Here the product must be heated at some point in the process for the expandable microspheres to expand. Expanded microsphereThe expanded microsphere is a material that has been heated to cause expansion. The product acts as a light weight filler in many products. The expanded microspheres are white, can be 15 to 90 micrometers in average diameter and can have a density of 15 to 70 kg/m³. The expanded microspheres are used as a lightweight filler in composite materials such as cultured marble, in waterborne paints and crack fillers/joint compound. CharacteristicsCharacteristics that make expandable microspheres unique,
References1. ^Patent US 3,615,972 ”Expansible thermoplastic polymer particles containing volatile fluid foaming agent and method of foaming the same” 2. ^Expandable microspheres in inks: advances in look and feel, Asia Pacific Coatings Journal, August 2009, page 32-33 3. ^“New developments with expandable microspheres”, Klas Elfving, Expancel. The Fifth International Conference Blowing agents and Foaming Processes 2003, Rapra. See also
2 : Thermoplastics|Hydrocarbons |
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