US-20260123626-A1 - EXPANDED MICROSPHERES FORMULATION

US20260123626A1US 20260123626 A1US20260123626 A1US 20260123626A1US-20260123626-A1

Abstract

A composition comprises thermally expanded microspheres suspended in a non-Newtonian fluid. The composition can be used for water-based applications, such as emulsion explosives, paint, water based coatings, coatings for thermal printing paper and other, porous ceramics, gypsum board, modelling clay, crack fillers, and cementitious compositions.

Inventors

Per Olov Fredrik SVENSSON
Per Erik AJDÉN

Assignees

NOURYON CHEMICALS INTERNATIONAL B.V.

Dates

Publication Date: 20260507
Application Date: 20251031
Priority Date: 20241031

Claims (16)

1 . A composition comprising thermally expanded microspheres suspended in a non-Newtonian fluid, wherein the composition has a solids content of about 0.5-20 wt.%, relative to the total weight of the composition.
2 . The composition of claim 1 , wherein the non-Newtonian fluid is a liquid comprising a non-Newtonian thickener.
3 . The composition of claim 2 , wherein the liquid is a water-based liquid, an organic liquid, an inorganic liquid, or combinations thereof.
4 . The composition of claim 2 , wherein the non-Newtonian thickener is a polysaccharide.
5 . The composition of claim 4 , wherein the polysaccharide is a diutan gum, a xanthan gum, a cellulose gum, a carrageenan, or combinations thereof.
6 . The composition of claim 4 , wherein the polysaccharide is a diutan gum.
7 . The composition of claim 1 , wherein the composition further comprises a biocide.
8 . The composition of claim 1 wherein the thermally expanded microspheres comprise a polymeric shell encapsulating a hollow core, wherein the hollow core optionally comprises a blowing agent.
9 . The composition of claim 8 , wherein the polymeric shell comprises one or more thermoplastic polymers.
10 . The composition of claim 9 , wherein the one or more thermoplastic polymers is selected from polymers obtained by polymerizing one or more vinyl monomers, lignins, polysaccharides, polysaccharide derivatives, polyesters, polyethers, polyacids, polyols, polyalkenes, polyanhydrides, or a combination thereof.
11 . The composition of claim 2 , wherein the thickener is present in an amount of about 0.01-10 wt.% relative to the total weight of the non-Newtonian fluid.
12 . The composition of claim 1 , that has a solids content of about 1-10 wt.%, relative to the total weight of the composition.
13 . The composition of claim 3 wherein the non-Newtonian thickener is a polysaccharide.
14 . The composition of claim 2 wherein the thermally expanded microspheres comprise a polymeric shell encapsulating a hollow core, wherein the hollow core comprises a blowing agent.
15 . The composition of claim 3 wherein the thermally expanded microspheres comprise a polymeric shell encapsulating a hollow core, wherein the hollow core comprises a blowing agent.
16 . A composition comprising: thermally expanded microspheres comprising a polymeric shell encapsulating a hollow core, wherein the hollow core comprises a blowing agent; and a biocide; wherein the thermally expanded microspheres are suspended in a non-Newtonian fluid; wherein the composition has a solids content of about 1-10 wt.%, relative to the total weight of the composition; wherein the non-Newtonian fluid is a liquid comprising a diutan gum present in an amount of about 0.01-10 wt.% relative to the total weight of the liquid; and wherein the polymeric shell comprises of one or more thermoplastic polymers selected from polymers obtained by polymerizing one or more vinyl monomers, lignins, polysaccharides, polysaccharide derivatives, polyesters, polyethers, polyacids, polyols, polyalkenes, polyanhydrides, or any combination thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of European Patent Application No. 24210159.0, filed on October 31st, 2025, which is hereby expressly incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure relates to a composition comprising thermally expanded microspheres suspended in a non-Newtonian fluid, and the use of said composition in water-based applications, such as for sensitizing emulsion explosives, paint, water based coatings, coatings for thermal printing paper and other, porous ceramics, gypsum board, modelling clay, crack fillers, and cementitious compositions. BACKGROUND Thermally expandable microspheres are known in the art and described in detail in, for example, US Patent No. 3615972. Various grades of expandable microsphere, having different expansion temperature, are commercially available from Nouryon under the trademark Expancel™, both as dry free flowing microspheres and as an aqueous slurry of microspheres. Thermally expandable microspheres typically comprise a blowing agent encapsulated within a thermoplastic shell. Upon heating, the blowing agent evaporates to increase the internal pressure, at the same time as the shell softens, resulting in significant expansion of the microspheres, normally from 2 to 5 times their diameter. Thermoplastic microspheres can be used in various applications as unexpanded or expanded. Examples of products where dry (essentially water free) expanded microspheres are used are as sensitizer in emulsion explosives and as light weight filler in solvent based paints and various thermosetting materials such as cultured marble, polyester putty and artificial wood. In many products, such as water based paints and coatings, thermal printing papers, porous ceramics and emulsion explosives, slurries (i.e., liquid suspensions) of expanded microspheres are used. A significant issue with the use of slurries of expanded microspheres in many applications, however, is slurry stability. It has been found that slurries of the expanded microspheres (prior to use in subsequent applications), which usually have a low final solids content of around 0.5-20 wt.% (typically around 1-10 wt.%), tend to be unstable (which is not typically a problem observed for equivalent slurries of unexpanded microspheres), hence there is generally a limited operating window between slurry formation and subsequent use in applications (usually in the region of a few minutes to a few hours, depending on the type of expanded microsphere, before the slurry becomes too unstable to be successfully used in the intended application). The same stability issue for expanded microspheres is not typically observed in the final application product (e.g., water based paints and coatings, thermal printing papers, porous ceramics, emulsion explosives, etc.) likely due to the presence of application-specific stabilizers/ binders/matrices/etc. and/or the substantial increase in solids content in the application product formulation, In view of this, slurries of expanded microspheres generally need to be produced on-site using specialist equipment and then used immediately. It would be preferable to find a solution to this slurry instability issue, such that said pre-application slurry of expanded microspheres could be produced off-site (e.g., at a single production facility) and transported to the place of application. BRIEF SUMMARY This disclosure provides a composition comprising thermally expanded microspheres suspended in a non-Newtonian fluid, wherein the composition has a solids content of about 0.5-20 wt.%, relative to the total weight of the composition. DETAILED DESCRIPTION The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses of the disclosure . Furthermore, there is no intention to be bound by any theory presented in the preceding background of the disclosure or the following detailed description. Moreover, it is contemplated that, in various non-limiting embodiments, it is to be appreciated that all numerical values as provided herein, save for the actual examples, are approximate values with endpoints or particular values intended to be read as “about” or “approximately” the value as recited. The inventors have found a highly effective solution to this issue: use a non-Newtonian fluid to suspend the expanded microspheres. To the best of the inventors’ knowledge, to date slurries of expanded microspheres have always used a Newtonian liquid to suspend the expanded microspheres (e.g., water, or water comprising an additive (e.g., a thickener) that yields a Newtonian solution, such as a Newtonian starch solution). By using non-Newtonian fluids (e.g., shear-thinning liquids) instead of Newtonian fluids, the resulting slurries were found to be surprisingly stable (i.e., stable for months). Accordingly, in a first aspect, the present disclosure relates to a composi