Polymer hollow particle, a method of preparing the same, and composite comprising the polymer hollow particle

1. A method of preparing polymer hollow particles, the method comprising:

a first step of providing, onto a substrate including an engraved pattern, at least one expandable particle comprising a foaming agent-containing expandable core and a thermoplastic polymer shell;

a second step of removing an excess of the at least one expandable particle from a resulting product of the first step;

a third step of expanding the at least one expandable particle in the engraved pattern of the substrate by thermally treating a resulting product of the second step; and

a fourth step of separating, from the substrate, expanded hollow polymer particles which are a resulting product of the third step,

wherein the at least one expandable particle is provided as monodispersed or polydispersed particles into the engraved pattern of the substrate in the first step, and the hollow polymer particles in the fourth step are monodispersed particles.

2. The method of claim 1 , wherein, in the first step, the at least one expandable particle comprising the expandable core and the thermoplastic polymer shell is provided with a solvent as a mixture onto the substrate including the engraved pattern, or is provided onto the substrate including the engraved pattern in a dry manner.

3. The method of claim 1 , wherein the thermal treating in the third step is performed at a temperature of about 50° C. to about 170° C.

4. The method of claim 1 , wherein the forming foaming agent comprises a non-fluorine-containing hydrocarbon compound that has a low boiling point and is present in a gaseous phase at a temperature equal to or lower than a softening point of a thermoplastic resin in the thermoplastic polymer shell.

5. The method of claim 1 , wherein the thermoplastic resin in the thermoplastic polymer shell of the at least one expandable particle comprises a polymer obtained from a polymerizable monomer or a polymer obtained as a reaction product of a polymerizable monomer and a cross-linking agent,

the polymerizable monomer comprises at least one selected from the group consisting of a nitrile monomer, a carboxylic acid monomer, a (meth)acrylic acid ester monomer, an acrylamide monomer, a maleimide monomer, a vinyl ether monomer, a vinyl ketone monomer, an aromatic divinyl monomer, a N-vinyl monomer, a halogenated vinyl monomer, and a combination thereof, and

the cross-linking agent comprises at least one selected from the group consisting of allyl methacrylate, triacryl formal, triallyl isocyanate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1, 10-decanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycoldi(meth)acrylate, trimethylolpropane trimethacrylate, glycerol dimethacrylate, dimethylol tricyclodecane diacrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, neopentyl glycol acrylate benzoate(Neopentylglycol benzoate acrylate), trimethylol propane acrylate benzoate, 2-hydroxy-3-acryloyloxy propyl methacrylate, hydroxypivalic acid neopentyl glycol diacrylate, ditrimethylolpropane tetraacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, and a combination thereof.

6. The method of claim 1 , wherein the thermoplastic resin in the thermoplastic polymer shell of the at least one expandable particle comprises a terpolymer comprising a (meth)acryl first repeating unit, a nitrile second repeating unit, and a third repeating unit having no reactivity with the (meth)acryl first repeating unit and the nitrile second repeating unit,

an amount of the (meth)acryl first repeating unit is about 10 wt % to about 50 wt %, an amount of the nitrile second repeating unit is about 30 wt % to about 80 wt %, and an amount of the third repeating unit is about 10 wt % to about 80 wt %, based on a total weight of the first to third repeating units in the thermoplastic resin.

7. The method of claim 1 , wherein the foaming agent in the expandable core of the at least one expandable particle comprises at least one selected from the group consisting of propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, petroleum ether, halogenated methane, tetra alkylsilane, azodicarbonamide, and a combination thereof.

8. The method of claim 1 , wherein the substrate including the engraved pattern comprises a line or hole pattern, and the hollow polymer particles each have a line or hole pattern on at least one surface thereof, according to the line or hole pattern of the substrate.

9. The method of claim 1 , wherein the hollow polymer particles each have a specific gravity of about 0.001 g/cm 3 to about 1 g/cm 3 .

10. The method of claim 1 , wherein each of the expanded hollow polymer particles is in the form of a one-body particle.

11. The method of claim 1 , wherein each of the expanded hollow polymer particles is substantially without grain boundary.

12. The method of claim 1 , further comprising surface-treating the hollow polymer particles to prevent agglomeration or binding between the particles.

13. The method of claim 1 , further comprising surface-treating the hollow polymer particles with a fluorine material.

14. The method of claim 1 , further comprising surface-treating the hollow polymer particles with 1,1-difluoroethane.