Methods of manufacturing articles having foam particles

1. A method of forming a cushioning element comprising foam particles, comprising:

providing a first composition comprising a plurality of foam particles dispersed or suspended in a liquid polymerizable composition;

polymerizing a first portion of the liquid polymerizable composition, forming a first layer including a first portion of a polymeric material which is the polymerized reaction product of the polymerizable composition, the first portion of the polymeric material at least partially encapsulating a first portion of the plurality of foam particles;

repeating the polymerizing and forming for a second iteration, polymerizing a second portion of the liquid polymerizable composition, forming a second layer including a second portion of the polymeric material at least partially encapsulating a second portion of the plurality of foam particles, and bonding the second layer to the first layer; and

repeating the polymerizing, forming and bonding for at least a third iteration, thereby forming a cushioning element having at least three layers, each layer including foam particles at least partially encapsulated by the first polymeric material and being bonded to another layer, the total number of layers being equal to the total number of iterations conducted;

wherein the polymerizing step includes a stereolithographic process utilizing a bottom-up process using continuous liquid interface production,

wherein the plurality of foam particles of the first composition includes a foamed thermoplastic material, and

wherein the first composition is maintained at a temperature of at least 10 degrees C. below a melting temperature of the thermoplastic material of the foam particles during the polymerizing, forming, and bonding iteration.

2. The method of claim 1 , wherein each polymerizing step comprises directing actinic radiation the respective portion of the first composition in an amount and for a duration sufficient to polymerize the respective portion of the liquid polymerizable composition.

3. The method of claim 1 , wherein each of the plurality of foam particles is a closed-cell foam particle having an outer skin.

4. The method of claim 1 , wherein each polymerizing step independently comprises polymerizing a predetermined target zone of the liquid polymerizable composition.

5. The method of claim 1 , wherein the method comprises: providing a container having an optically transparent member, and a build surface within the container facing the optically transparent member, forming a build region between the optically transparent member and the build surface; filling the build region with the first composition; irradiating the build region through the optically transparent member; and advancing the optically transparent member and the build surface away from one another to form a subsequent build region between the layer and the optically transparent member; wherein an iteration includes the filling, irradiating and advancing steps, and the irradiating step includes the polymerizing, forming and bonding steps.

6. The method of claim 5 , wherein the irradiating comprises exposing at least a portion of the build region to a source of ultraviolet radiation, directed light radiation, projected light, or a combination thereof.

7. The method of claim 1 , wherein the cushioning element comprises at least one non-polymerized region.

8. The method of claim 1 , wherein the liquid polymerizable composition comprises a precursor to a polymer selected from the group consisting of: a polyurethane, a polysiloxane, a polyurea, a polyamide, a melamine formaldehyde, a polyepoxide, a polyimide, an olyoxybenzylmethylenglycolanhydride, a polycyanurate, a polyester, a urea-formaldehyde, and combinations thereof, wherein the plurality of foam particles comprises a foamed polymeric material that comprises a polymer selected from the group consisting of: polyesters, polyamides, vinyl polymers, polyolefins, polyacrylonitriles, polyphenylene ethers, polycarbonates, polyureas, styrene polymers, co-polymers thereof, and combinations thereof.

9. The method of claim 1 , wherein the plurality of foam particles comprise foam particles having a density of about 0.1 grams per cubic centimeter to about 0.8 grams per cubic centimeter.

10. The method of claim 1 , wherein the plurality of foam particles includes ellipsoidally-shaped foam particles or essentially spherically-shaped foam particles or both.

11. The method of claim 10 , wherein at least 20 percent of the plurality of foam particles are spheroid or ellipsoid in shape.

12. The method of claim 1 , wherein the polymeric material has a first set of mechanical properties, and the plurality of foam particles have a second set of mechanical properties that is different from the first set of mechanical properties.