Hollow glass microspheres used as fillers can effectively enhance the added value of products, and the selection and addition methods are also crucial.
How to choose the appropriate hollow glass microspheres?
The main specifications of hollow glass microspheres are composed of true density, compressive strength, and particle size. Therefore, when selecting, it is necessary to consider the application, process, and desired effect for reference. Let us illustrate with a few examples:
Case One: Thermal insulation coatings
Analysis-
a. Want to achieve a lower thermal conductivity
b. Low density to resist settling, large application area
c. Can avoid high shear processes, so compressive strength does not need to be too high
Recommendation-
In this case, it is recommended to use low-density hollow glass microspheres with a strength of about 5MPa, such as HL20, HL25, HL30. This can achieve better thermal insulation effects, but it should be added later, and simple stirring can achieve excellent dispersion.
Case Two: Rubber soles or products
Analysis-
a. Want lightweight, so density should be low
b. Adding hollow microspheres may cause a decrease in physical properties
c. Process strength is higher, so compressive strength should be high
Recommendation-
In this case, it is recommended to use HS42K, which has been surface silanized, with a strength of about 55MPa. This type of hollow glass microspheres has better adhesion with resin, and the negative effects on physical properties will be reduced. They should be added in the final mixing stage.
How to add hollow glass microspheres?
Because of their extremely low density, they can be added incrementally, with each addition being half of the remaining amount. This gradual addition helps to prevent them from floating in the air, ensuring better dispersion. Additionally, for small-scale additions, it is recommended to use appropriate containers directly with protective masks. However, for larger-scale additions, extraction methods are recommended. One of the biggest concerns with hollow glass microspheres is their high breakage rate during processing, which can lead to a loss of their intended effects. Therefore, besides selecting products of appropriate specifications, mutual cooperation in the process is also essential for complementing each other.
