Thermally expandable microspheres prepared from bio-based monomers

Patent metadata

Field	Value
Publication number	US-11208538-B2
Application number	US-201816758637-A
Country	US
Kind code	B2
Filing date	Nov 20, 2018
Priority date	Nov 21, 2017
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

The present disclosure provides thermally expandable microspheres at least partially prepared from bio-based monomers and a process of their manufacture. The microspheres include a thermoplastic polymer shell encapsulating a blowing agent. The thermoplastic polymer shell includes a copolymer of an itaconate dialkylester and at least one aliphatic or aromatic mono-ethylenically unsaturated comonomer. The itaconate dialkylester has the formula (1):where each of R1 and R2, separately from one another, is an alkyl group having 1-4 carbon atoms, and the copolymer includes 0-50 wt. % of vinyl aromatic comonomers, based on the total weight of the comonomers. The present disclosure further provides expanded microspheres usable in a variety of applications.

First claim

The invention claimed is:

1. Thermally expandable microspheres comprising a thermoplastic polymer shell encapsulating a blowing agent, wherein the thermoplastic polymer shell comprises a copolymer of an itaconate dialkylester and at least one aliphatic or aromatic mono-ethylenically unsaturated comonomer, wherein the itaconate dialkylester is according to formula (1):

wherein each of R 1 and R 2 , separately from one another, is an alkyl group having from 1 to 4 carbon atoms, and
wherein the copolymer includes from 0 to 50 wt. % of vinyl aromatic comonomers, based on the total weight of the comonomers.

2. The microspheres according to claim 1 , wherein the itaconate dialkylester is selected from dimethyl itaconate (DMI), diethyl itaconate (DEI), di(n-propyl) itaconate, diisopropyl itaconate, and dibutyl itaconate (DBI).

3. The microspheres according to claim 1 , wherein the copolymer includes less than 50 wt. % of the itaconate dialkylester monomer, based on the total weight of the comonomers.

4. The microspheres according to claim 1 , wherein the copolymer includes less than 10 wt. % of the vinyl aromatic comonomers.

5. The microspheres according to claim 1 , wherein the at least one aliphatic or aromatic mono-ethylenically unsaturated comonomer is selected from unsaturated lactones, acrylonitrile, methacrylonitrile, methyl methacrylate, vinylidene chloride, methyl acrylate, (meth)acrylic acid and (meth)acrylamide.

6. The microspheres according to claim 5 , wherein the unsaturated lactone is selected from α-methylene-γ-valerolactone (MVL), β-methyl-α-methylene-γ-butyrolactone (MMBL), and α-methylene-γ-butyrolactone (MBL).

7. The microspheres according to claim 1 , wherein the blowing agent is a hydrocarbon.

8. A process for the manufacture of the thermally expandable microspheres of claim 1 , comprising the step of polymerizing ethylenically unsaturated monomer(s) by aqueous suspension polymerization using a free-radical initiator in the presence of a blowing agent, wherein at least one ethylenically unsaturated monomer is the itaconate dialkylester according to the formula (1).

9. The process according to claim 8 , further comprising the step of stabilizing the suspension with SiO 2 , optionally modified with one or more organosilane groups, or Mg(OH) 2.

10. Expanded microspheres obtained by thermal expansion of the microspheres according to claim 1 .

11. A process for the manufacture of expanded microspheres, comprising heating the thermally expandable microspheres according to claim 1 such that the thermally expandable microspheres expand.

12. The microspheres according to claim 1 , wherein the copolymer is free of the vinyl aromatic comonomers.

13. The microspheres according to claim 7 , wherein the hydrocarbon is selected from n-butane, isobutane n-pentane, isopentane, cyclopentane, neopentane, hexane, isohexane, neo-hexane, cyclohexane, heptane, isoheptane, octane, isooctane, decane, dodecane, isododecane, and any combination thereof.

Assignees

• Nouryon Chemicals Int Bv

Inventors

• Nordin Ove
• Ekmarker Anna
• Waltersson Evelina

Classifications

• C08J2335/02

  Characterised by the use of homopolymers or copolymers of esters (C08J2335/06, C08J2335/08 take precedence) · CPC title

• C08J2203/14

  Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons · CPC title

• B01J13/14 Primary

  Polymerisation; cross-linking · CPC title

• C08J9/0066

  Use of inorganic compounding ingredients · CPC title

• C08J9/232 Primary

  by sintering expandable particles · CPC title