Thermo expandable microcapsulesKUREHA Microsphere

What is KUREHA Microsphere?

KUREHA Microsphere is a closed cell foaming agent that is sometimes referred to as thermo expandable microcapsules.
The hydrocarbon blowing agent resides inside an acrylic shell. When exposed to heat the shell softens while the pressure inside increases, allowing for rapid expansion.
Expansion starts gradually at the Tstart (activation) and reaches its peak expansion diameter at the Tmax (Maximum expansion temperature).
Once cooled, the microsphere maintains its shape encapsulating the blowing agent.
If the microsphere is heated past the recommended Tmax or heated longer than recommended, the blowing agent will gradually escape the shell and the microspheres will lose their shape.
KUREHA has lineup of microsphere grades suitable for a wide range thermoplastics; including advanced grades that are compatible with higher temperature polymers.
KUREHA Microsphere is used in wide range of applications including ceiling materials, glass run channels, weather strips, shoe soles, foam ink, wallpaper, heat release tape, artificial leather, and 3D printers.

When heated, the volume increases 50 to 170X depending on the grade used.
Expandable microspheres benefits include weight reduction, improved moldability, thermal and sound absorption.
Microspheres are a precision foaming agent that are characterized by easy control of specific gravity, retention of closed cells, small sphere diameter and uniform distribution.
Microspheres provide the flexibility to be foamed in resin and within high permeability materials such as fibers and paints.

Series	Grade	Average particle size before expansion (μm)	Average particle size after expansion¹⁾ (μm)	Expansion ratio	Expansion start temperature (Tstart) （℃）	Maximum expansion temperature (Tmax) （℃）
H	H750	15-25	60-100	50-65	120-160	160-170
	H850	30-45	155-225	125-155	120-135	170-185
	H880	20-35	85-135	55-70	135-160	175-185
S	S2340	15-25	70-140	100-170	170-190	230-245
S	S2640	15-25	70-140	100-170	190-215	250-265
Unique	H1100-S (before heat treatment)	40-55	-	-	170-225	-
Unique	H1100-S (after heat treatment)	40-55	145-210	45-70²⁾	145-160	175-195

1) calculated by expansion ratio
2) after heat treatment (150℃, 5min)

KUREHA Microsphere grades are classified by "H" and "S" or "Unique" according to processing temperatures and expansion characteristics.
H series are suitable for expansion at 160℃-190℃
S series can be used in temperatures above 190 ℃, and are suitable for molding of engineering plastics and elastomers.
Unique series which have unique expansion characteristics.

The values provided on this website are representative values based on our measurement results, not guaranteed values.
Please check laws, regulations and product safety before using the product corresponding to purpose and application.
For safe handling of products, please be sure to check Safety Data Sheet (SDS) in advance.
Please use inquiry form to request SDS.
Information provided on this website is the result obtained based on specific conditions, and we do not guarantee that same result will be obtained by using our materials.

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