Expandable polylactic acid-based thermal and protective packaging and method thereof

Abstract

A molded foam article is provided having at least one surface with at least a portion formed with a skin to improve the thermal and mechanical properties of the molded foam article without requiring changes in material, density, or foam particle size.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 369,005, filed July 21, 2022, which is incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to molded foam articles, and specifically to molded foam articles formed from polylactic acid having a skin-formed surface. [Background technology]

[0003] Molded foam is used in a variety of industries, including insulation and protective packaging, construction, infrastructure support, food service, and consumer products such as surfboards. Molded foam articles are typically produced from expandable polystyrene (EPS) using well-known manufacturing processes. However, EPS-based foam articles have various drawbacks that require compensating for the properties of the EPS-based foam articles so that they can be successfully used for their desired purposes.

[0004] Consumer foam articles such as insulated shipping containers are commonly used to transport meal kits, confectionery products, cakes, other perishable foods, and pharmaceuticals such as vaccines. Other insulated shipping containers require a hydrophobic barrier that lacks significant resistance to water transfer and requires more resources than can be recovered through recycling.

[0005] Furthermore, transporting equipment and other heavy items requires protective foam with higher compression and flex properties. EPS-based packaging must be at least 0.5 inches thick and must be produced at an ultra-high density to achieve the higher compression and flex properties. This increases the energy and material usage required for production. In other words, EPS-based packaging uses higher density foam to achieve higher compression strength, but at the expense of increased material content. Keeping material content low while increasing compression strength is desirable, but is not possible with EPS-based packaging.

[0006] The shock and vibration protection provided by protective packaging varies with direction. Conventional EPS-based packaging has mechanical properties in the xy plane compared to the xz or yz plane that vary within 20% for larger, heavier parts and within 10% for smaller, lighter parts. This variation is a by-product of the EPS production method. However, to provide sufficient protection for heavy parts without increasing the weight of the protective packaging, it is desirable to have a low-weight foam product designed to have mechanical properties in different directions that vary by more than 20%.

[0007] Therefore, there is a need for improved molded foam articles to overcome one or more of the technical challenges described above. [Brief explanation of the drawings]

[0008] The detailed description will be set forth with reference to the accompanying drawings. The use of the same reference numbers may indicate identical items and similar things. Various embodiments may utilize elements and / or components other than those shown in the drawings, and some elements and / or components may not be present in various embodiments. Elements and / or components in the drawings are not necessarily drawn to scale. Throughout this disclosure, singular and plural terms may be used interchangeably where appropriate.

[0009] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0010] [Figure 1] FIG. 1 is a perspective view of a molded bead foam article having a skin-forming surface according to the present disclosure. [Figure 2A] FIG. 1 is a side view of a molded bead foam article having a skin-forming surface according to the present disclosure. [Figure 2B] FIG. 1 is a side view of a molded bead foam article having a skin-forming surface according to the present disclosure. [Figure 3A] FIG. 1 is a top view of a molded bead foam article having printed identification information according to the present disclosure. [Figure 3B] FIG. 1 is a top view of a molded bead foam article having a skin-forming surface with printed identification information in accordance with the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Provided herein are molded foam articles, including molded foam articles having one or more skin-forming surfaces. Specifically, it has been unexpectedly discovered that forming a skin on one or more surfaces on a molded bead foam article enhances the properties of the molded bead foam article to a degree greater than, or in some cases impossible to achieve, a comparable EPS molded foam article.

[0012] Throughout this disclosure, various aspects are presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the present disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all possible subranges and individual numerical values within that range. For example, the description of a range such as 1 to 6 should be considered to have specifically disclosed subranges such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., as well as individual numbers within that range, e.g., 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0013] As used herein, the term "about" in reference to a dimension refers to plus or minus 10% of the dimension.

[0014] Molded bead foam articles Molded foam articles are disclosed herein. In some embodiments, the molded foam article comprises polylactic acid (PLA). As used herein, "molded foam article" refers to an article formed from polymeric foam that has undergone an expansion and bead-forming process. The article can be in the form of a two-dimensional panel or a three-dimensional structure, such as a box. Other polymeric foams can be expanded and molded in a manner similar to expandable polystyrene, such as polypropylene, polyethylene, polyurethane, and polylactic acid.

[0015] In some embodiments, a molded bead foam article includes at least one surface, at least a portion of which is skinned. As used herein, a "skinned" surface or portion of a surface is a surface or portion of a surface that has undergone a "skinning" process in which a portion of the surface is exposed to sufficient heat, optionally with the application of pressure, such that the molded beads on the surface of the molded bead foam article experience an increased degree of fusion compared to beads in the interior of the molded bead foam article. Skinning results in a smoother surface compared to non-skinned surfaces, and the skinned surface imparts increased compressive strength, tensile strength, and flexural strength to the molded bead foam article compared to molded bead foam articles without a skinned surface. Furthermore, it has been unexpectedly discovered that skinning can be performed on curved or irregular surfaces, enabling these mechanical and thermal strengthenings on surfaces that previously could not be strengthened, even by conventional means.

[0016] In some embodiments, a portion of the surface is skin-formed. For example, the surface may have a size suitable for use as an insulated shipping container, and the skin-formed portion of the surface may have a size suitable for printing identifying information on the skin-formed portion of the surface. In some embodiments, the entire surface is skin-formed to impart the improved mechanical and thermal properties described herein to the molded bead foam article. In some embodiments, two or more separate portions of the surface are skin-formed, such as two portions, three portions, or more. In some embodiments, the skin-formed portion has a shape, such as a square, rectangle, circle, or another shape, corresponding to a particular object intended to be transported within the molded foam article. In some embodiments, the skin-formed portion is intended for printing identifying information. In other embodiments, the skin-formed portion is intended for creating wrinkles or creases in the molded foam article to facilitate bending or folding.

[0017] In some embodiments, the at least one surface skin-forming portion has a greater resistance to compression than a conventional EPS-based foam article having the same density. In some embodiments, the at least one surface skin-forming portion has a lower density than a conventional EPS-based foam article having the same resistance to compression.

[0018] While not intending to be bound by any particular theory, conventional EPS molding processes produce EPS-based molded foam articles that cannot be skinned due to the presence of pentane blowing agent within the EPS beads. Performing a skin-forming process on a freshly molded, or in some cases aged for up to 72 hours, EPS-based molded foam article results in either excessive expansion of the beads that form the surface of the molded article or subsequent shrinkage of the cells that form a weak crystalline skin, thereby deteriorating the mechanical properties of the article. If a specific compression resistance, tensile strength, or flexural strength is desired in an EPS-based molded foam article, the density must be increased. Similarly, if a specific density and / or weight is desired in an EPS-based molded foam article, some compression resistance or flexural strength must be sacrificed. High compressive strength and modulus in EPS-based molded foam articles are achievable only at densities of at least 2 pcf, even as high as 4 pcf. In contrast, the skin-forming portion of at least one surface of a PLA-based molded bead foam article of the present disclosure has the same compressive strength and modulus at densities of only 1.6 to 1.8 pcf. In some embodiments, at least one surface skin-forming portion has a density of about 1.0 pcf to about 6.0 pcf.

[0019] In some embodiments, the at least one surface skin-forming portion has a compression resistance that is 30% to 50% greater than the same PLA-based molded bead foam article without the at least one skin-forming portion. It has been unexpectedly discovered that precise selection of the at least one surface portion to be skin-formed allows for selective reinforcement of the PLA-based molded bead foam article. For example, skinning only the edges, corners, or multiple edges and / or corners improves the compression resistance of the edges and / or corners, allowing the molded bead foam article to pass a drop test. Conventional EPS-based foam articles require increased density to pass a drop test.

[0020] In some embodiments, the skin-formed portion of at least one surface is leak-proof. Molded foam articles are often used as refrigeration containers, and shipping certain commodities, such as seafood, is ideally carried out in a shipping container that does not secrete any liquid from within the shipping container. It has surprisingly been discovered that skin-forming at least a portion of at least one surface of a molded foam article can increase resistance to water leaching through the skin-formed portion. In some embodiments, the inner surface can be skin-formed to prevent secretion of liquid. In some embodiments, the outer surface can be skin-formed to prevent secretion of liquid. In some embodiments, both the inner and outer surfaces can be skin-formed to prevent secretion of liquid.

[0021] In some embodiments, at least one surface skin-forming portion has an R-value that remains unchanged for at least one year when exposed to water. As used herein, "R-value" refers to an insulating material's resistance to thermal energy transfer and is calculated according to Equation I. In contrast, the R-value of an EPS-based molded foam article decreases by about 6% after prolonged exposure to water, and the R-value of extruded polystyrene (XPS) decreases by about 48% after prolonged exposure to water. The PLA-based molded articles described herein have similar R-values compared to EPS or XPS, but the R-value changes negligibly after prolonged exposure to water.

number

[0022] In some embodiments, molded bead foam articles having at least one skin-forming portion on at least one surface can be used as shipping containers without additional materials. In some embodiments, PLA-based molded bead foam articles include identifying information printed directly onto at least one skin-forming portion on at least one surface. As described above, it has been unexpectedly discovered that the skin-forming process produces a smooth surface, making the skin-forming portion suitable for direct printing of identifying information, eliminating the need for labels.

[0023] In some embodiments, the identifying information is printed with ink containing ethanol, methyl ethyl ketone (MEK), water, or a combination thereof, thereby preserving the recyclability of the PLA-based molded article.

[0024] In some embodiments, molded bead foam articles have anisotropic compression modulus, anisotropic flexural modulus, or both. It has been unexpectedly discovered that by skinning at least a portion of at least one surface to form a skin-forming surface, the mechanical properties of a bead foam article can be anisotropically altered. The use of such bead foam articles can provide differentiated protection when simultaneously exposed to horizontal and vertical vibrations. For example, a tall and heavy object could use an anisotropic foam protective edge that resists vertical compression and potentially damaging vibration while providing simple contact protection in the horizontal direction. In contrast, a high-density EPS-based foam article designed for vertical compression, for example, would have poorer protection in the horizontal direction. The anisotropic nature of skin-forming foam advantageously allows the foam to be more easily manually broken or crushed in one direction than another. Therefore, protective packaging utilizing skin-forming foam with anisotropic mechanical properties can be broken down into small pieces when removed from a box, or allows consumers to break the protective packaging into pieces that fit more easily into a waste container. Additionally, constructing the foam with engineered failure minimizes the creation of floating beads upon failure.

[0025] Molded bead foam articles having at least one skin-forming portion on at least one surface may be intended for use when transporting heavy equipment, and the skin-forming portion may be positioned under the feet or wheels of the heavy equipment because the molded bead foam article has an increased compressive modulus in a direction perpendicular to the skin-forming portion.

[0026] In some embodiments, the molded bead foam article is in the form of a protective guard, such as an edge guard or corner guard with multiple sides. In some embodiments, fewer than all sides of the protective guard have a skin-forming portion. It has been unexpectedly discovered that by forming a box with selected sides having at least one skin-forming portion, the mechanical protection of the protective guard can be tailored to the application or the goods stored / transported therein. Previous attempts to create packaging with customized mechanical properties have sometimes involved the use of additional foam portions formed from different materials or having different densities, requiring secondary molding processes and / or equipment. Skinning at least a portion of the surface of the molded bead foam article to create a skin-forming portion can be performed in the same mold as the molded bead foam article itself, immediately after molding in a small device near the mold, or after receipt of the molded bead foam article by the user but prior to installation as protective packaging, thereby enabling the creation of custom packaging with minimal material and manufacturing costs.

[0027] In some embodiments, the molded bead foam article is in the form of a collapsible shipping container configured to fold into a container for shipping goods. As used herein, "collapsible shipping container" refers to a shipping container that can be unfolded into a flat configuration. For example, a shipping container in the form of a six-sided box can be unfolded so that each of the six sides is flat and connected to at least one other side. It has unexpectedly been discovered that skinning a portion of at least one surface of a molded bead foam article allows for the formation of a surface suitable for printing identification information, such as shipping details and product identification. In some embodiments, the interface between two sides of the collapsible shipping container is interlocked to create a freestanding box. The properties of boxes made with collapsible "C"-shaped panels or individual panels are comparable to molded boxes with similar dimensions. Skinning two or more sides increases tensile and compressive properties. The collapsible shipping container occupies approximately 80% less volume during shipping and storage.

[0028] The skin-forming molded articles described herein can be used in applications such as automobile headrests. For example, shaped foam articles can be selectively skin-formed to achieve a desired balance of compressive, tensile, and shear strength, providing the necessary stiffness to withstand normal stresses within a vehicle while also selectively providing a "softer" or more cushioned feel to the passenger.

[0029] Another potential application for skin-molded articles is for spare tire covers, which may include recesses for tire removal tools or other devices. These covers are often made from expanded polypropylene (EPP). The advantageous ability to skin-molde around holders or grip points allows for the use of PLA for spare tire covers, increasing the compressive strength of the tire cover without compromising the ability to incorporate grips or recesses for tools. Skin-molding around the edges of the spare tire cover provides abrasion resistance and strength.

[0030] Method for producing molded foam articles Also disclosed herein are methods for producing molded foam articles. In one aspect, the method includes producing a molded bead foam article as described above. In another aspect, the method includes molding a plurality of foam beads comprising polylactic acid to produce the molded foam article, and skinning at least a portion of at least one surface of the molded foam article.

[0031] In some embodiments, the method includes skinning at least a portion of at least one surface of the molded bead foam article while the molded bead foam article is in the mold, hi other embodiments, the at least one portion is skinned after the molded bead foam article is removed from the mold.

[0032] In some embodiments, the method includes selectively reinforcing one or more sides and / or one or more corners with a skin-forming portion. As discussed above, skinning one or more sides and / or one or more corners advantageously increases the compression resistance of the sides and / or corners, increasing drop resistance without changing density.

[0033] In some embodiments, the method includes printing identifying information on the skin forming portion.

[0034] In some embodiments, the method is performed in-line. In other words, each step of forming the molded foam article is subsequently performed in approximately the same location. In some embodiments, the method is performed by an automated device. In other words, a device such as a robotic device may perform each step necessary to form the molded foam article, such as delivering foam particles to a mold, forming the molded foam article, removing the molded foam article from the mold, transporting the molded foam article to a skin-forming device, and folding the molded foam article onto a transport device. It has unexpectedly been discovered that skinning at least a portion of one or more surfaces of a molded foam article to form a skin-forming portion increases thermal and mechanical properties over those of common degradable solutions used in place of conventional EPS, such as cotton batts, paper or starch liners, or shipping containers containing extruded starch solutions.

[0035] The methods described herein advantageously allow for the ability to skin the perimeter of, for example, a circular panel without altering the properties of the top or bottom surfaces. This advantageously allows the circular panel to have higher compressive strength. Such modifications can be made to panels having any shape to selectively increase the compressive strength of the panel.

[0036] The methods described herein further advantageously allow for the ability to alternate skin-forming and non-skin-forming areas on the same article for superior protection. In other words, skin-forming can be in discrete areas or locations and is not limited to the entire surface. By forming a molded foam article with discrete skin-forming areas, superior cushioning can be achieved by alternating skin-forming areas with non-skin-forming areas. [Example]

[0037] The present disclosure may be further understood with reference to the following non-limiting examples.

[0038] Example 1: Leak-proof PLA-based panels PLA-based foam panels were produced as described herein. To skin the panel surface, the panels were pressed on a T-shirt press platen at 310°F for 15 seconds. After removal from the platen, the skinned surface was observed to have a smooth appearance due to reduced texturing, as depicted in Figure 1. The panels were then subjected to a standard water leaching test used for EPS-based molded articles. The panels were machined into disks with a 3-inch diameter and a 1.5-inch thickness, and a hollow column was positioned on top of the disk and filled with 1000 mL of water. After 15 minutes, no water was observed to penetrate or leach through the disk. In contrast, PLA-based panels without a skinned surface showed water leaching or water droplets after 2-3 minutes.

[0039] Example 2: Extended leakproof testing of PLA-based panels PLA-based foam panels were produced as described herein and skinned as described in Example 1. The panels had dimensions of 8"x8"x1.5". The panels were manipulated into a "bowl"-like shape. 250 mL of water was placed in the "bowl" and the panels were left overnight. No leaching of water was observed. The panel weight increased by approximately 0.1 g (less than a 1% increase), indicating some water absorption into the panel surface.

[0040] Example 3: Flexural Properties of PLA-Based Molded Foam Articles with Skin-Forming Surfaces PLA-based molded foam articles were produced as described herein. The articles had a thickness of 1.5" and were cut into 2" wide strips according to ASTM C203. Three strips were not skinned. Six strips were skinned for 20 seconds on one side using a platen having a temperature of 310°F. Three skinned strips were tested according to ASTM C203 so that the crossbar used in the standard test was in contact with the skinned surface, and three skinned strips were tested so that the crossbar was in contact with the opposing surface. The three non-skinned strips and the three skinned strips tested so that the crossbar was in contact with the skinned surface (Figure 2A) had a flexural strength of 45.6 psi and a modulus of 416. The three skinned strips tested so that the crossbar was on the opposite side of the skinned surface (Figure 2B) had a flexural strength of 50 psi and a modulus of 637.

[0041] Example 4: Compressive Strength of PLA-Based Molded Foam Articles with Skin-Formed Surfaces PLA-based molded foam panels were produced as described herein. The panels had a density of 1.5 pcf. The top surface of the panels was skinned at 310°F for 20 seconds. The compressive strength of the panels was measured by applying a compressive force to the skinned surface. Before skinning, the panels had a compressive strength of 18 psi. After skinning, the panels had a compressive strength of 20 psi. Because skinning occurred in a direction perpendicular to the measurement, the compressive strength of the panels remained relatively unchanged.

[0042] Example 5: Compressive strength changes from skinning the proximal surface PLA-based molded foam cubes were produced as described herein. The cubes had a density of 1.5 pcf. Two opposing sides of a first cube were skinned, and the compressive strength of the resulting skinned cube was measured by applying a force to the non-skinned side in a direction parallel to the skinned sides. In other words, a force was applied to the "top" of the cube with the "left" and "right" sides skinned. Before skinning, the first cube had a compressive strength of 18 psi. After skinning two opposing sides, the cube had a compressive strength of 28.4 psi. A second cube was skinned on four adjacent sides, and a force was applied in a direction parallel to the skinned sides. In other words, a force was applied to the "top" of the second cube with the "left," "right," "front," and "back" sides skinned. Before skinning, the second cube had a compressive strength of 18 psi. After skinning four sides, the second cube had a compressive strength of 32.4 psi. Without the skinned surface, a similar increase in compressive strength would require an increase in foam density of approximately 60% to 80%.

[0043] Additionally, a second cube with four skinned sides exhibited a compressive strength of 20 psi when measured on any of the four skinned sides (with two skinned and two non-skinned sides parallel to the direction of the force) and 32.4 psi when measured on the non-skinned sides (with all four skinned sides parallel to the direction of the force). These anisotropic properties were obtained without any changes in material, density, or foam particle size.

[0044] Example 6: Printing identification information directly onto the skin formation surface PLA-based molded foam articles were produced as described herein, and barcodes were printed on the surfaces of the articles. The VIAjet™ L12 printer used LS6101 black as the "A1" ink, utilizing ethanol as the solvent, and LS7011 black as the "A2" ink, utilizing MEK as the solvent. Printing was performed on a moving conveyor at a line speed of 50 feet per minute. The inkjet head was selected for printing a QR code with a size of 96x86 pixels at 300 dpi resolution. Printing was performed on both the skin-formed and non-skin-formed surfaces, and the ink was allowed to dry for 2 seconds. In this test, the ability to read / scan the QR code determined print quality. Figure 3A depicts the print quality on the non-skin-formed surface for both the A1 and A2 inks, and Figure 3B depicts the print quality on the skin-formed surface for both the A1 and A2 inks. Only the A2 ink produced a scannable QR code on the non-skin-formed surface, but both inks were viable on the skin-formed surface.

[0045] Example 7: Skin formation process for EPS-based molded articles EPS-based molded articles were formed with a density of 1.2 pcf and a thickness of 1.5 inches. These articles had an initial flexural strength of 0.213 MPa. When the newly molded EPS was exposed to a heated platen at a temperature of 250°F, the foam beads overexpanded, forming a rough, uneven surface. This overexpansion resulted in a slight reduction in flexural strength accompanied by a deterioration in the apparent appearance. When newly molded EPS with a thickness of 1.5 inches was exposed to a heated platen at a temperature of 300°F, the foam beads contracted and melted, forming a highly crystalline skin. This resulted in a 30% decrease in flexural strength and a 20% decrease in resilience when tested according to ASTM C203. When the newly molded EPS was exposed to the heated platen, additional pentane blowing agent was released from the EPS, as evidenced by the strong odor emitted from the panel. Therefore, processing EPS on a heated platen for extended periods requires additional ventilation to prevent the accumulation of VOCs such as pentane in the air. EPS aged for at least 72 hours was less reactive than freshly molded EPS, but also formed crystalline surfaces that reduced the flexural strength and elasticity of the article. The skin formation process resulted in a reduction in flexural strength to 0.146 MPa.

[0046] Example 8: Skin formation process for EPP-based molded articles EPP-based molded articles were formed and aged using a conventional process. One EPP-based article, 1.5 inches thick, was exposed to a heated platen having a temperature of 250°F. At 250°F, no change was observed on the outer surface of the EPP article. At a heated platen temperature of 300°F to 310°F, the surface of the EPP-based article began to change, with the boundaries of the individual beads softening and smoothing. At a heated platen temperature of 310°F to 320°F, the article melted, losing 1 / 8 inch in thickness and forming voids between the beads as they melted. The EPP-based molded article was unable to form a skin due to its sensitivity to such high heat and tendency to melt.

[0047] Example 9: Skin formation process for EPE-based and E(PS-co-PE)-based molded articles Expandable polyethylene (EPE)-based molded articles were purchased from Worldwide Foam, Indiana, USA, and expandable polystyrene / polyethylene copolymer (E(PS-co-PE))-based molded articles were purchased from Engineered Foam Products Ltd., Northampton, England, United Kingdom. E(PS-co-PE) was an Arcel® brand product. The articles were subjected to heated platens at various temperatures ranging from 200 to 320°F. No changes in surface appearance were observed at lower temperatures and dwell times. At higher temperatures, the surfaces of both the EPE-based and E(PS-co-PE)-based articles exhibited rough surfaces and a slight reduction in flexural strength.

[0048] While the present disclosure has been described with reference to several embodiments, it will be understood by those skilled in the art that the present disclosure is not limited to such embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions, or equivalent arrangements not described herein, but which are commensurate with the spirit and scope of the present disclosure. Unless otherwise expressly stated or understood within the context of use, conditional language used herein, such as "can," "could," "may," or "might," is generally intended to convey that a particular embodiment includes certain features, elements, or functional capabilities, while other embodiments are not included. Additionally, while various embodiments of the present disclosure have been described, it should be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure is not to be deemed limited by the foregoing description, but is limited only by the appended claims.

Claims

1. A molded bead foam article comprising polylactic acid, the molded bead foam article comprising at least one surface, at least a portion of the at least one surface being skin-formed.

2. 10. The molded bead foam article of claim 1, wherein the at least one surface skin-forming portion has greater resistance to compression than a conventional EPS-based foam article having the same density.

3. 10. The molded bead foam article of claim 1, wherein the skin-forming portion of the at least one surface has a lower density than a conventional EPS-based foam article having the same compression resistance.

4. 10. The molded bead foam article of claim 1, wherein the skin-formed portion of the at least one surface has a compression resistance that is 30% to 50% greater than a surface of an unskinned PLA-based molded bead foam article.

5. 10. The molded bead foam article of claim 1, wherein the skin-formed portion of the at least one surface comprises a skin-formed corner or a skin-formed edge of the molded bead foam article, the skin-formed corner or skin-formed edge being effective to increase the drop resistance of the molded bead foam article without changing its density.

6. 10. The molded bead foam article of claim 1, wherein the at least one surface skin-forming portion has a density of from about 1.0 pcf to about 6.0 pcf.

7. 10. The molded bead foam article of claim 1, wherein the at least one surface skin-forming portion is leak-proof.

8. 10. The molded bead foam article of claim 1, wherein the at least one surface skin-forming portion has an R-value that remains unchanged for at least one year when exposed to water.

9. 10. The molded bead foam article of claim 1, further comprising identifying information printed directly on the skin-forming portion of said at least one surface.

10. 10. The molded bead foam article of claim 9, wherein the identifying information is printed with an ink comprising ethanol, methyl ethyl ketone, water, or a combination thereof.

11. 10. The molded bead foam article of claim 1, wherein the molded bead foam article has an anisotropic compression modulus and / or an anisotropic flexural modulus.

12. 10. The molded bead foam article of claim 1, further comprising a label having product information printed directly on said skin-forming surface.

13. The molded bead foam article of claim 1 , wherein the molded bead foam article is in the form of a box having multiple sides.

14. 14. The molded bead foam article of claim 13, wherein fewer than all sides of the box have a surface skin forming portion.

15. 10. The molded bead foam article of claim 1, wherein the molded bead foam article is in the form of an automobile headrest.

16. The molded bead foam article of claim 1 , wherein the molded bead foam article is in the form of a spare wheel cover.

18. The molded bead foam article of claim 1 , wherein the at least one surface having a skin-forming portion is curved.

17. The molded bead foam article of claim 1 , wherein the molded bead foam article comprises a blend or copolymer of polylactic acid.

18. 1. A method for producing a molded bead foam article, comprising: molding a plurality of foam beads comprising polylactic acid in a mold to produce the molded bead foam article; and skinning at least a portion of at least one surface of said molded bead foam article.

19. 20. The method of claim 18, wherein the at least one surface skin-forming portion is skin-formed while the molded bead foam article is in the mold.

20. 20. The method of claim 18, wherein the at least one surface skin-forming portion is skin-formed after the molded bead foam article is removed from the mold.

21. 20. The method of claim 18, further comprising printing identifying information on the skin-forming portion of the at least one surface.

22. The method of claim 18 , wherein the method is performed in-line.

23. 20. The method of claim 18, wherein the method is performed near a packaging facility.

24. 20. The method of claim 18, wherein the method is performed by an automated device.

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