Polymer composition and method for coating wooden pallets with a polymer composition - Patents.com

Abstract

A polymer composition for coating wooden pallets is provided. The polymer composition includes a mixture of at least one of polyurea, polyurethane, silicone elastomer, and combinations thereof in a predetermined ratio. The polymer composition imparts desirable properties to the wooden pallet, such as high impact and abrasion resistance, tensile strength, and antistatic properties, along with flexural strength. The present invention also provides a method for coating the polymer composition onto the wooden pallet. The matrix coating process results in much stronger adhesion due to overlapping coatings of the polymer composition on the sides of the wooden pallet, reducing the amount of wear of the polymer composition during the coating of the wooden pallet. The present invention also provides a wooden pallet coated with the polymer composition. The wooden pallet coated with the polymer composition has properties such as high impact resistance, abrasion resistance, and antistatic properties.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Patent Application No. 202123049643, a patent application filed in India entitled "Polymer composition and method for coating wooden pallets with a polymer composition", filed on October 29, 2021. FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to coating wooden pallets, and more particularly to polymer compositions and methods for coating wooden pallets with polymer compositions. [Background technology]

[0002] A pallet is a flat transport structure that provides stable support for goods that can be lifted by a forklift, front loader, pallet jack, electric crane, or jacking device. A pallet provides the structural foundation for a unit load, allowing for efficient handling and storage. Wooden pallets typically consist of three or four spar boards that support several deck boards onto which goods are placed. Pallets are manufactured from a variety of materials. Wooden pallets dominate the market and offer excellent value in terms of price and performance. Wood is a hard material that is cheap and easily machined into a variety of dimensions as required. Wood composite pallets also offer a hard, competitively priced product, are easily recyclable, and are typically stackable, improving space utilisation in transport and storage. However, wooden pallets are not water resistant and are prone to moisture and rot. Wooden pallets require fumigation or heat treatment even for one-time export packaging, which adds additional costs and increases the time for customs clearance. To overcome these problems, sanding and painting techniques are used to protect wooden pallets from water vapor and termites. Sanding helps avoid chemicals, but exposure to wood dust can be harmful to human health. In any case, sanding and painting techniques are less reliable, less durable and time consuming.

[0003] Recent studies have also described the coating of aliphatic polymers on the surface of wooden pallets. Such aliphatic polymer coatings include coating of polyurea or polyurethane on the surface of wooden pallets. However, the use of polyurea for coating wooden pallets makes the product expensive, and polyurethane is very sensitive to humidity conditions. Therefore, there is a need for improved, cost-effective polymer compositions and methods for coating wooden pallets with polymer compositions to impart toughness and flexibility. Summary of the Invention

[0004] According to an embodiment of the present invention, a polymer composition for coating wooden pallets is provided. The polymer composition includes a mixture of at least one of polyurea, polyurethane, silicon elastomer, and combinations thereof in a predetermined ratio. The mixture includes either polyurea and polyurethane in a predetermined ratio of 60:40 to 80:20, or polyurea, polyurethane, and silicon elastomer in a predetermined ratio of 60:37:03 to 78:19:03. The polymer composition provides desirable properties to the wooden pallet, such as high impact and abrasion resistance, elongation strength, and antistatic properties, along with bending strength. According to another embodiment of the present invention, there is provided a method for coating a polymer composition on a wooden pallet. The method includes heating a mixture of at least one of polyurea, polyurethane, silicone elastomer, and combinations thereof in a predetermined ratio at 70°C to 85°C to obtain a polymer composition in a molten state. The mixture includes either polyurea and polyurethane in a predetermined ratio of 60:40 to 80:20, or polyurea, polyurethane, and silicone elastomer in a predetermined ratio of 60:37:03 to 78:19:03. The method also includes coating the wooden pallet with the molten polymer composition to form a layer of a predetermined thickness on the surface of the wooden pallet. The coating of the molten polymer composition is carried out using a matrix coating process. The method further includes drying the coating on the surface of the wooden pallet at room temperature.

[0005] According to yet another embodiment of the present invention, a wooden pallet is provided. The wooden pallet includes a layer of a polymer composition of a predetermined thickness coated on a surface of the wooden pallet. The polymer composition includes a mixture of at least one of polyurea, polyurethane, silicone elastomer, and combinations thereof in a predetermined ratio. The mixture includes either polyurea and polyurethane in a predetermined ratio of 60:40 to 80:20, or polyurea, polyurethane, and silicone elastomer in a predetermined ratio of 60:37:03 to 78:19:03. To further clarify the advantages and features of the present invention, a more detailed description of the invention follows with reference to specific embodiments thereof, illustrated in the accompanying drawings, in which it is understood that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of the scope. The present invention will be described and explained with additional specificity and detail in the accompanying drawings, in which: The invention will be described and explained with additional specificity and detail in the accompanying figures. [Brief description of the drawings]

[0006] [Figure 1]1 is a flow chart depicting the steps involved in a method for coating a polymer composition onto a wooden pallet, in accordance with an embodiment of the present invention. [Diagram 2] FIG. 1 depicts a wooden pallet coated with a polymeric composition in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not necessarily be drawn to scale. Moreover, chemical compounds and parameters used herein with respect to method steps may be represented in the figures by conventional symbols, and the figures may show only certain details pertinent to understanding the embodiments of the present disclosure, so as not to obscure the figures with details that would be readily apparent to one of ordinary skill in the art having the benefit of the description herein. For the purposes of promoting an understanding of the principles of the present disclosure, reference will be made below to the embodiments illustrated in the drawings and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the present disclosure is intended thereby. Such changes and further modifications in the illustrated system, and such further applications of the principles of the present disclosure as would normally occur to one skilled in the art, should be construed as being within the scope of the present disclosure. The terms "comprise", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that includes a list of steps does not include only those steps, but may also include other steps not expressly listed or inherent to such process or method. Similarly, the use of one or more components, compounds, and ingredients following "comprises" does not, without further constraints, exclude the presence of other components or compounds or ingredients or additional components. Throughout this specification, the appearances of the phrases "in one embodiment", "in another embodiment" and similar language may, but do not necessarily, all refer to the same embodiment.

[0008] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The systems, methods, and examples provided herein are illustrative only and are not intended to be limiting. In the following specification and claims, reference will be made to a number of terms which shall be defined to have the following meanings: The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. The present invention relates to a polymer composition for coating wooden pallets. The present invention mainly focuses on a hybrid polymer composition that provides tensile and bending strength to wooden pallets. The present invention also provides a method for coating wooden pallets. The method mainly includes a matrix coating process for coating wooden pallets. The present invention also relates to a wooden pallet coated with the polymer composition.

[0009] As used herein, the term "matrix coating process" refers to a method of finishing a cured coating to improve release and low friction properties. The present invention provides a wooden pallet having improved bending and tensile strength. The wooden pallet is coated with a number of layers of a polymer composition. In an embodiment, the polymer composition comprises a mixture of at least one of polyurea, polyurethane, silicone elastomer, and combinations thereof in a predetermined ratio. The mixture comprises either polyurea and polyurethane in a predetermined ratio of 60:40 to 80:20, or polyurea, polyurethane, and silicone elastomer in a predetermined ratio of 60:37:03 to 78:19:03. The mixture comprises polyurea and polyurethane in a predetermined ratio of 65:35. The mixture comprises polyurea, polyurethane, and silicone elastomer in a predetermined ratio of 65:32:03.

[0010] The wooden pallet is selected from the group consisting of plywood, fuel wood and wood veneer sheets. In one embodiment, the wooden pallet is made from plywood. In another embodiment, the wooden pallet is made from fuel wood. The polyurea and polyurethane blend is designed to impart flexural and tensile strength to the wooden pallet. The polyurea, polyurethane and silicone elastomer blend is designed to impart flexural and tensile strength as well as antistatic properties to the wooden pallet. In polymer compositions containing polyurea and polyurethane, a reaction occurs between an isocyanate and a blend of polyols and enamines. The enamine content helps reduce moisture sensitivity, while the polyol content provides flexural strength. The polyurethane and polyurea mixture provides tensile strength to wooden pallets. Silicone elastomers are antistatic compounds. Polymer compositions including polyurea, polyurethane and silicone elastomers provide wooden pallets with antistatic properties along with high flexural and tensile strength. As used herein, the term "polyurea" refers to a type of elastomer derived from the reaction product through step-growth polymerization of an isocyanate component and a synthetic resin blend component.

[0011] As used herein, the term "polyurethane" refers to a polymer composed of organic units joined by carbamate (urethane) bonds. As used herein, the term "silicone elastomer" refers to a durable and highly resistant elastomer (rubber-like material) composed of silicone (a polymer) that contains silicon along with other molecules such as carbon, hydrogen and oxygen. The structure of a silicone elastomer always contains a siloxane backbone (a silicon-oxygen chain) and organic moieties bonded to the silicon. In another embodiment of the present invention, a method for coating a polymer composition onto a wooden pallet is provided. The method mainly focuses on the matrix coating process for coating the wooden pallet. FIG. 1 is a flow chart depicting the steps involved in a method for coating a polymeric composition onto a wooden pallet, according to one embodiment of the present invention.

[0012] The method for coating a polymer composition on a wooden pallet starts with heating a mixture of at least one of polyurea, polyurethane, silicone elastomer, and combinations thereof in a predetermined ratio at 70°C to 85°C to obtain a polymer composition in a molten state in step 102. The mixture includes either polyurea and polyurethane in a predetermined ratio of 60:40 to 80:20, or polyurea, polyurethane, and silicone elastomer in a predetermined ratio of 60:37:03 to 78:19:03. The wooden pallet is selected from the group consisting of plywood, fuel wood and wood veneer sheets. The mixture comprises polyurea and polyurethane in a predetermined ratio of 65:35. The mixture comprises polyurea, polyurethane and silicone elastomer in a predetermined ratio of 65:32:03. In such an embodiment, since polyurea, polyurethane and silicone elastomer are thermosetting, the mixture is heated to a temperature in the range of 70°C to 85°C to melt the mixture in order to obtain a polymer composition of uniform liquid consistency. In an exemplary embodiment, the mixture is heated at 80°C to obtain a desired mixture viscosity for coating the polymer composition onto the wooden pallet. In an embodiment, in step 104, the wooden pallet is coated with the molten polymer composition to form a layer of a predetermined thickness on the surface of the wooden pallet. The coating of the molten polymer composition is performed using a matrix coating process. The coating of the molten polymer composition on the surface of the wooden pallet is performed using a gun controlled by either a manual spray method or a robotic arm. The coating of the layer of the molten polymer composition on the surface of the wooden pallet is performed in a spray coating chamber. The predetermined thickness of the layer of the polymer composition coated on the surface of the wooden pallet is in the range of 0.5 mm to 1 mm.

[0013] In one embodiment, the predetermined thickness of the layer of polymer composition is uniform across the surface of the wooden pallet, hi such an embodiment, the layer of polymer composition is coated evenly onto the surface of the wooden pallet. In one embodiment, the predetermined thickness of the layer of polymer composition is variable across the surface of the wooden pallet. In such an embodiment, the layer of polymer composition is coated on the surface of the wooden pallet as required. In one embodiment, spraying the molten polymer composition onto the surface of the wooden pallet may include maintaining the temperature of the molten polymer composition between 70° C. and 85° C. In such an embodiment, the temperature of the molten polymer composition is maintained between 70° C. and 85° C. in order to maintain a constant viscosity of the molten polymer composition for proper coating. In one such embodiment, in step 106, the coating on the surface of the wooden pallet is dried at room temperature. The coated wooden pallet is allowed to air dry at room temperature for about 30 minutes. The layer of a predetermined thickness formed by the mixture of polyurea and polyurethane is configured to impart bending and tensile strength to the wooden pallet. The layer of a predetermined thickness formed by the mixture of polyurea, polyurethane and silicone elastomer is configured to impart antistatic properties as well as bending and tensile strength to the wooden pallet.

[0014] The matrix coating process includes forming a matrix of at least four wooden pallets and spray coating them in a specific manner. As used herein, the term "wooden pallet" refers to a wooden structure with a predetermined dimension and shape. First, the flat surface of the base is spray coated and dried for about 30 minutes, and the opposite side of the flat surface is spray coated with the same matrix form of the wooden pallet. In such an embodiment, a fixture may be made and configured to hold at least four wooden pallets. Furthermore, the fixture may be transferred to the spray coating chamber via a conveyor. The spray coating chamber may include side inlet and outlet portions that can be used for coating at least four wooden pallets. In one embodiment, the chamber may be designed to accommodate a four wooden pallet matrix. The coated wooden pallets are subsequently dried. For this purpose, the fixture is designed to hold at least four wooden pallets at the edges and off-center, so that the coating is sprayed on the maximum area of ​​the side of the wooden pallet base of each of the at least four wooden pallets. The process involves moving a fixture holding down at least four half-coated wooden pallets by conveyor out of the spray coating chamber for drying.

[0015] While the at least four half-coated wooden pallets are held for drying, the next set of wooden pallets can be brought into the spray coating chamber for spraying. In a similar manner, the cycle is repeated for about 30 minutes with an average of 1.5 minutes per wooden pallet. Additionally, at least four previously coated wooden pallets may be placed on a fixture to expose the coated surfaces of the remaining sides of the pallets to the additional coating. This provides an overlap from the sides for stronger adhesion. Again, the spray process is repeated on the other side of the wooden pallets, and then the set of fully coated wooden pallets is transferred to air drying. In yet another embodiment of the present invention, a wooden pallet 200 is provided. FIG. 2 depicts a wooden pallet 200 coated with a polymeric composition according to one embodiment of the present invention.

[0016] The wooden pallet 200 includes a layer 202 of a predetermined thickness of a polymer composition coated on a surface of the wooden pallet 200. The polymer composition includes a mixture of at least one of polyurea, polyurethane, silicone elastomer, and combinations thereof in a predetermined ratio. The mixture includes either polyurea and polyurethane in a predetermined ratio of 60:40 to 80:20, or polyurea, polyurethane, and silicone elastomer in a predetermined ratio of 60:37:03 to 78:19:03. The wooden pallet 200 is selected from the group consisting of plywood, fuel wood, and wood veneer sheets. The mixture includes polyurea, polyurethane and silicone elastomer in a predetermined ratio of 65:32:03. The layer 202 of predetermined thickness formed by the mixture of polyurea and polyurethane is configured to impart bending and tensile strength to the wooden pallet 200. The layer 202 of predetermined thickness formed by the mixture of polyurea, polyurethane and silicone elastomer is configured to impart antistatic properties as well as bending and tensile strength to the wooden pallet 200. The predetermined thickness of the layer 202 of polymer composition coated on the surface of the wooden pallet 200 ranges from 0.5 mm to 1 mm.

[0017] The present invention allows for polymer coating of wooden pallets 200. The polymer composition provided by the present invention provides desirable properties to wooden pallets 200, such as high impact and abrasion resistance, tensile strength, and antistatic properties, along with flexural strength. The use of aliphatic compounds in the polymer composition allows for the prevention of rust stains on wooden pallets. The present invention also provides a method for coating the polymer composition onto wooden pallets 200. The method includes a matrix coating process for coating the polymer composition onto wooden pallets 200, which results in much stronger adhesion due to overlapping coatings of the polymer composition on the sides of the wooden pallet 200, reducing the amount of wear of the coating material, i.e., the polymer composition. The present invention also provides wooden pallets 200 coated with the polymer composition. Wooden pallets 200 coated with the polymer composition have properties such as high impact resistance, abrasion resistance, tensile strength, flexural strength, and antistatic properties.

[0018] Although specific language has been used to describe the present invention, no limitation is intended to arise thereby. As would be apparent to one skilled in the art, various operational modifications may be made to the methods for implementing the inventive concepts taught herein. Examples of embodiments are shown in the figures and above specification. Those skilled in the art will understand that one or more of the described elements may be well combined into a single functional element. Alternatively, certain elements may be divided into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, the order of the methods described herein may be changed and are not limited to the manner described herein. Furthermore, the operations of any flow diagrams need not be performed in the order shown, and not all operations necessarily need to be performed. Also, operations that are not dependent on other operations may be performed in parallel with other operations. The scope of the embodiments is in no way limited to these specific examples.

Claims

1. A wooden pallet base; and a polymer composition coated on the surface of a wooden pallet substrate; A coated wooden pallet comprising: The polymer composition comprises: (i) a first mixture comprising polyurea and polyurethane in a first predetermined ratio of 60:40 to 80:20; and (ii) a second mixture comprising polyurea, polyurethane, and silicone elastomer in a second predetermined ratio of 60:37:03 to 78:19:03; and The polymer composition is coated onto the surface of the wooden pallet substrate using a matrix coating process; The matrix coating process includes curing a coating of the polymer composition and polishing the cured coating. Coated wooden pallets.

2. 10. The coated wooden pallet of claim 1, wherein the wooden pallet is selected from the group consisting of plywood, fuel wood, and wood veneer sheets.

3. A coated wooden pallet as described in claim 1, wherein the first mixture comprises polyurea and polyurethane in a third predetermined ratio of 65:

35.

4. The coated wooden pallet of claim 1, wherein the second mixture comprises polyurea, polyurethane and silicone elastomer in a third predetermined ratio of 65:32:

03.

5. The coated wooden pallet of claim 1, wherein the wooden pallet substrate is coated with a predetermined number of layers of the polymer composition.

6. A coated wooden pallet as described in claim 1, wherein the second mixture comprises polyurea, polyurethane and silicone elastomer in a second predetermined ratio, and the polymer composition is coated onto the surface of the wooden pallet substrate at a predetermined thickness of 0.5 mm to 1 mm.

7. 1. A method for coating a polymer composition onto a wooden pallet, comprising: Heating the polymer composition at 70°C to 85°C to obtain a polymer composition in a molten state, The polymer composition comprises: (i) a first mixture comprising polyurea and polyurethane in a first predetermined ratio of 60:40 to 80:20; and (ii) a second mixture comprising polyurea, polyurethane, and silicone elastomer in a second predetermined ratio of 60:37:03 to 78:19:03; a step including one of the steps forming a coating on the surface of the wooden pallet from the polymer composition in a molten state to form a layer of a predetermined thickness on the surface of the wooden pallet; curing the coating on the surface of the wooden pallet; and A method comprising the step of polishing the hardened coating on the surface of the wooden pallet.

8. 8. The method of claim 7, wherein the wooden pallet is selected from the group consisting of plywood, fuel wood, and wood veneer sheets.

9. The method of claim 7, wherein the first mixture comprises polyurea and polyurethane in a third predetermined ratio of 65:

35.

10. The method of claim 7, wherein the second mixture comprises polyurea, polyurethane and silicone elastomer in a third predetermined ratio of 65:32:

03.

11. The method of claim 7, wherein forming a coating on the surface of the wooden pallet comprises forming a predetermined number of layers of the polymer composition on the surface of the wooden pallet.

12. The method described in claim 7, wherein forming a coating on the surface of the wooden pallet with the polymer composition is carried out using a matrix coating process.

13. 8. The method of claim 7, wherein the coating of the molten polymer composition on the surface of the wooden pallet is performed using a gun controlled by one of a manual spray method and a robotic arm.

14. 8. The method of claim 7, wherein the predetermined thickness of the layer of polymer composition is uniform across the surface of the wooden pallet.

15. 8. The method of claim 7, wherein the predetermined thickness of the layer of polymer composition varies across the surface of the wooden pallet.

16. The method of claim 7, further comprising the step of drying the coating on the surface of the wooden pallet at room temperature.

17. A wooden pallet base, and a predetermined number of layers of a polymer composition coated on a surface of a wooden pallet substrate, wherein each of the predetermined number of layers has a predetermined thickness; A wooden pallet comprising: The polymer composition comprises: (i) a first mixture comprising polyurea and polyurethane in a first predetermined ratio of 60:40 to 80:20; and (ii) a second mixture comprising polyurea, polyurethane, and silicone elastomer in a second predetermined ratio of 60:37:03 to 78:19:03; and A predetermined number of layers of the polymer composition are coated onto the surface of the wooden pallet substrate using a matrix coating process; The matrix coating process involves curing and polishing each of a predetermined number of layers of the polymer composition. Wooden pallet.

18. 18. The wooden pallet of claim 17, selected from the group consisting of plywood, fuel wood, and wood veneer sheets.

19. The wooden pallet of claim 17, wherein the second mixture comprises polyurea, polyurethane and silicone elastomer in a third predetermined ratio of 65:32:

03.

20. A wooden pallet as described in claim 17, wherein each of a predetermined number of layers of a predetermined thickness comprises a first mixture including polyurea and polyurethane, and the thickness ranges from 0.5 mm to 1 mm.

21. A wooden pallet as described in claim 17, wherein each of a predetermined number of layers of a predetermined thickness comprises a second mixture of polyurea, polyurethane and silicone elastomer and has a thickness ranging from 0.5 mm to 1 mm.

22. 18. The wooden pallet according to claim 17, wherein the thickness of each of the predetermined number of layers of predetermined thickness of the polymer composition coated on the surface of the wooden pallet substrate ranges from 0.5 mm to 1 mm.

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