A process for surface modification of materials

Patent metadata

Field	Value
Publication number	US-2018117828-A1
Application number	US-201615553350-A
Country	US
Kind code	A1
Filing date	Feb 16, 2016
Priority date	Mar 9, 2015
Publication date	May 3, 2018
Grant date	—

Abstract

The present invention relates to surface modification of materials. In particular the invention relates to a process for surface modification of polymeric materials to make the surface non-stick in order to reduce the ability of materials to stick on it and thus provide an easy flow. The process comprises embossing the surface of an object with a pattern comprising micropillars having different shapes (circle, square, rectangular, polygonal prismatic) with an equivalent circular diameter, height and pitch in the range 10-200 microns; applying a layer of adhesive to get a coverage of 0.1 to 5 mg/cm on the embossed surface either by spray coating or dip coating; depositing 0.2 to 1.2 mg/cm of hydrophobic particles wherein the hydrophobic particles have a particle size in the range 0.1 to 10 microns.

First claim

1 . A process for surface modification of materials comprising:
(i) embossing the surface of an object with an embosser comprising micropillars with an equivalent circular diameter, height and pitch each in the range of 10-200 microns; (ii) applying 0.1 to 5 mg/cm 2 of adhesive on the embossed surface resulting from step (i); (iii) depositing 0.2 to 1.2 mg/cm 2 of hydrophobic particles on the surface resulting from step (ii);
wherein the hydrophobic particles have a particle size with d50 in the range 0.1 to 10 microns.

2 . A process for surface modification of materials as claimed in claim 1 wherein the adhesive has a shear elastic modulus <0.3 MPa at frequency ˜1 Hz.

3 . A process surface modification of materials as claimed in claim 1 wherein the application of the adhesive is by spray coating or dip coating.

4 . A process for surface modification of materials as claimed in claim 1 wherein the hydrophobic particles are a mixture of two different sizes of particles wherein the smaller particles are in the range 2-8 times smaller than the larger particles.

5 . A process for surface modification of materials as claimed in claim 1 wherein the d50 of the smaller hydrophobic particles is in the range 0.2 to 2 microns and the d50 of the larger hydrophobic particles is in the range 0.8 to 8 microns.

6 . A process for surface modification of materials as claimed in claim 1 , wherein the d50 of the smaller hydrophobic particles is in the range 0.2 to 0.5 microns and the d50 of the larger hydrophobic particles is in the range 0.8 to 1 microns.

7 . A process for surface modification of materials as claimed in claim 1 wherein the hydrophobic particles are selected from water insoluble inorganic materials such as metal or non-metal oxides; metal carbonates; metal phosphates; natural or synthetic silicates; or crosslinked polymers such as polystyrene, polyethylene, polyvinyl acrylates.

8 . A process for surface modification of materials as claimed in claim 1 wherein the hydrophobic particles are deposited by applying a solvent with a vapour pressure greater than 50 mm Hg at 25′′C comprising the particles.

9 . A process for surface modification of materials as claimed in claim 8 wherein solvent is selected from methanol, ethanol, isopropanol, hexane, chloroform, benzene, xylene or toluene.

10 . An object comprising an embossed surface obtainable by the process as claimed in claim 1 wherein the embossed surface comprises micropillars with an equivalent circular diameter, height and pitch each in the range of 10-200 microns and wherein the micropillars are surface coated with 0.1 to 5 mg/cm 2 of an adhesive and 0.2 to 1.2 mg/cm 2 of hydrophobic particles wherein the hydrophobic particles have a particle size with d50 in the range 0.1 to 10 microns.

11 . (canceled)

12 . (canceled)

13 . An object as claimed in claim 10 comprising a hydrophobically modified embossed surface.

14 . An object as claimed in claim 10 wherein the object is a polymeric material selected from high density polyethylene (HDPE), low density polyethylene (LDPE), polyethylene terephthalate (PET), polypropylene (PP) or polystyrene (PS) or their derivatives.

15 . An object as claimed in claim 10 wherein the hydrophobically modified surface has a water contact angle greater than 120° and a liquid roll off at tilt angles of ≤10°, for liquids having viscosities above 100 cP.

Assignees

• Conopco Inc Dba Unilever
• Conopco Inc Dba Unilever

Inventors

• Das Somnath
• Muralidharan Girish
• Pramanik Amitava

Classifications

• B05D7/02

  to macromolecular substances, e.g. rubber (treatment or coating of shaped articles made of macromolecular substances C08J7/00) · CPC title

• C08J7/0423 Primary

  with at least one layer of inorganic material and at least one layer of a composition containing a polymer binder · CPC title

• B05D2601/22

  Silica · CPC title

• C08J2325/06

  Polystyrene · CPC title

• B29C59/02

  by mechanical means, e.g. pressing {(B29C59/007 takes precedence; embossing expanded porous articles B29C44/5627)} · CPC title