Playground equipment with protective coating

Abstract

Playground equipment including one or more structures wherein at least one of the structures includes a protective coating. The coating may be a polyurea and is applied to an exposed surface of the playground equipment structure at a first thickness, and may be applied to an unexposed surface of the playground equipment structure at a second thickness, wherein the second thickness is less than the first thickness. Preferably, the first thickness is between 20 and 50 mils and the second thickness is between 5 and 30 mils. The first thickness and second thickness may also be substantially the same.

Description

DESCRIPTION OF THE INVENTION

1. Field of the Invention

The present invention relates to playground equipment with a protective coating and a method for applying a protective coating thereto.

2. Background of the Invention

Playground equipment, including the decks, steps and landings of the playground equipment, is subject to high levels of exposure and wear since the equipment is usually positioned outdoors and is climbed on during normal use. This results in degradation of the surfaces, particularly the wear surfaces, at a rapid pace. In addition, the sun's rays can heat up surfaces, such as decks and steps, and surface temperatures can easily exceed 200° F. Contact with such hot surfaces by unprotected skin can result in burns. Another problem with most metal playground equipment surfaces in areas where high humidity is common is the growth of mold or fungus. Mold and fungus have been linked as a health risk to children.

Conventionally, some type of protective coating is often applied to the surfaces of playground equipment to guard against wear, environmental degradation, and to provide for insulation from hot surfaces. For example, the coating used on playground equipment surfaces may be vinyl chloride or PVC applied by a dipping method. PVC is a synthetic polymer material (or resin). The PVC used in this application is typically a rigid material that is mechanically tough and resistant to water and chemicals. However, PVC is relatively unstable to heat and light (particularly ultraviolet (“UV”) light). This instability can be improved by the addition of stabilizers. However, stabilizers are undesirable because they often contain toxic and/or expensive materials, such as heavy metals such as lead, barium, calcium or cadmium, or contain organotin compounds. Another way to stabilize PVC is through the addition of low molecular called plasticizers. While these compounds improve the properties of PVC, many contain esters of organic acids, such as phthalates and adipates, which can be toxic and may leach or volatilize into the environment, and again add to the cost of the PVC.

While PVC provides a suitable surface coating for playground equipment, it thus has many undesirable characteristics related to durability, repair, UV stability, and environmental issues. During the manufacture of the building block ingredient of PVC (vinyl chloride monomer), dioxin and other pollutants are emitted and these can present health hazards. In addition, PVC products can leach toxic additives. For example, flooring can release plasticizers called phthalates. When PVC reaches the end of its useful life it can either be land filled, where it leaches toxic additives, or incinerated, again emitting dioxin and heavy metals. If burned, hydrogen chloride gas and dioxin are formed.

As such, PVC is generally undesirable as a coating for playground equipment as it exhibits poor characteristics with regard to expense, stability, durability, and environmental safety.

SUMMARY OF THE INVENTION

The present invention provides playground equipment including one or more structures covered with a protective coating that is a polyurea or other non-PVC material. Preferably, the polyurea is TuffShell™ M25 available from SafeStructure LLC of Solon Ohio.

A protective coating according to this invention preferably exhibits, but is not limited to, the following characteristics:

Tensile Strength                 1500 to 3000 psi
Elongation Percentage (at 25° C.) 280 to 700 percent
Hardness                         40 to 95 Shore A
Tear Strength                    300 to 600 PLI
Thermal Shock Rating             +400 to −80° F.
Notched Izod Impact              65 to 85 inch-pounds/inch (285 to
                                 375 J/m)

The protective coating may be applied on a structure of playground equipment at a uniform thickness or may be applied on an exposed surface of a playground equipment structure at a first thickness, and applied to an unexposed surface of the playground equipment structure at a second thickness, wherein the second thickness is less than the first thickness. If applied in this fashion, the first thickness is preferably between 25 and 50 mils and the second thickness is preferably between 5 and 15 mils.

The protective coating may also include a crinkle finish (i.e., a textured or rough surface, as opposed to a smooth outer surface), and the crinkle finish may be solely on the exposed surface.

It is to be understood that the descriptions of this invention herein are exemplary and explanatory only and are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an example of playground equipment in accordance with the present invention.

FIG. 2 is a flowchart depicting a method for applying a protective coating to playground equipment in accordance the present invention.

FIG. 3 depicts a side view of a structure of playground equipment in accordance with the present invention.

FIG. 4 depicts an example of protective coating with a crinkle finish in accordance with the present invention.

FIG. 5 depicts a side view of a structure of playground equipment with an uneven application of coating in accordance with the present invention.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings.

FIG. 1 depicts one example of playground equipment according to the invention. Playground equipment 100 includes one or more structures 150 that are preferably formed from stamped metal. However, any type of metal, metal alloy, or other material suitable for forming playground equipment may be used. Playground equipment includes any type of recreational structure (e.g., slides, jungle gyms, see saws, climbers, swings, waterpark slides, etc.), as well as site amenities. Site amenities include structures such as shelters, benches, ramadas, bleachers, and bus stop structures (i.e., benches and shelters). Typical structures found in playground equipment or site amenities (hereinafter playground equipment and site amenities are collectively referred to as “playground equipment”) include decks, landings, steps, railings, seating surfaces, roofs, handles and/or ladders. As shown in FIG. 1, structures 150 are the steps and deck of a slide. One or more of structures 150 are covered with protective coating 160.

Protective coating 160 provides for a wear and weather resistant surface. In addition, protective coating 160 may exhibit non-skid characteristics, may reduce the temperature of the playground equipment surface to which it is applied, and may provide a degree of padding. Protective coating 160 is preferably formed from a two component system that, when mixed, creates a polyurea. The two components used to create a polyurea are typically a diisocyanate and a diamine, although a polyurea for use in the invention may be formed in any suitable manner.

Preferably, the polyurea used is TuffShell™ M25 available from SafeStructure LLC of Solon Ohio. The two components of TuffShell™ M25 include a TuffShell™ TM M25 Isocyanate (Part A) and a TuffShell™ M25 Resin (Part B). Part A is a pre-polymerized diisocyanate blend and Part B is a liquid aromatic polyamine/polyoxyalkyleneamine. Part B may include various color pigments in order to produce different colors in the resulting polyurea. Other components, including chain extenders, additives, and/or catalysts can also be included in Part B. Optionally, special materials, such as mildewcides and release agents (e.g. Teflon), may be included in Part A. The protective coating is not be limited to polyureas, but may be any non-PVC coating, and an exemplary coating according to the invention preferably exhibits the following characteristics:

Tensile Strength                 1500 to 3000 psi
Elongation Percentage (at 25° C.) 280 to 700 percent
Hardness                         40 to 95 Shore A
Tear Strength                    300 to 600 PLI
Thermal Shock Rating             +400 to −80° F.
Notched Izod Impact              65 to 85 inch-pounds/inch (285 to
                                 375 J/m)

FIG. 2 depicts an exemplary method for applying a protective coating to a structure of playground equipment according to the invention. Initially, in step 201, a structure of the playground equipment to be coated is selected. This structure may be any part of the playground equipment to which a protective coating is applied, such as a deck, landing, or step.

In step 202, protective coating 160 is applied to an exposed surface of the selected structure. An exposed surface of a structure is defined as any surface of the structure that is typically exposed to greater amounts of environmental exposure and use than other surfaces. Conversely, an unexposed surface of a structure is defined as any surface of the structure that is typically exposed to lesser amounts of environmental exposure and use. Referring back to FIG. 1, in the case of landing structure 150, the horizontal top 156 and vertical surfaces 157 are exposed surfaces because they are subject to more environmental exposure (e.g., sun, rain, wind) and are subject to more use wear (e.g., foot traffic). Conversely, the horizontal under surface 158 of landing structure 150 is an unexposed surface since it receives less environmental exposure and use. It is possible that for some structures, every surface may be an exposed surface or every surface may be an unexposed surface.

In step 202, protective coating 160 is applied to the exposed surface at a first thickness. This thickness may be any thickness desired, but is preferably 25 to 50 mils.

The protective coating may be applied in any manner, but is preferably applied by conventional spraying techniques, most preferably with a plural component spray system and an impingement spray gun. Plural component spray systems are preferable for use with TuffShell™ M25 as it is a two-part polyurea. However, other spray systems, such as a single component spray system, would be acceptable for use with single part polyureas and other coatings.

Preferably the plural component spray system is a Model GX-7 or GX-8 P spray gun and a Model H20/35 Pro plural proportioning pump/control unit both manufactured by Graco/Gusmer Corporation of Lakewood, N.J. The spray system has an adjustable output between 24 lb/min and 38 lb/min and a maximum pressure rating of 3500 psi. It is capable of spraying materials having a viscosity between 250 cps and 1500 cps. In addition to Graco/Gusmer, Glas Craft (Indianapolis, Ind.) or other comparable plural component systems are also acceptable. Other types of spray equipment utilized for plural component spray systems include Fusion (Graco), Probler (Glas Craft) and Gap (Gusmer) spray guns.

Due to the viscosity of certain coatings at room temperature, such as TuffShell™ M25, it is preferable to heat the material and pre-heat the hose lines of the spray system used from ambient temperature to a range of 160° F. to 225° F. for application of the coating. Such heating will allow for easier flow of the material and thus easier coating of the playground equipment.

The protective coating may be applied by hand or be automated, such as through robotic methods. In some cases, the protective coating may be applied with a combination of hand and automated methods. Alternatively, coatings may be applied in any suitable manner, such as through rolling or brushing.

In step 203, protective coating 160 is applied to an unexposed surface in the same manner as the exposed surface. However, the protective coating is applied to an unexposed surface at a second thickness. The second thickness may be of any thickness desired, but is preferably less than the first thickness and is preferably between 5 to 15 mils.

In step 204, the type of finish is selected. If the finish is to be left smooth, additional application of the protective coating may not be required. If a skid resistant finish is desired, a crinkle finish may be applied in step 205.

Crinkle finishes are also known as wrinkle or orange-peel finishes because they have a textured or rough feel. The crinkle finish is typically achieved by applying a light dusting of the protective coating on the surface from a distance greater than the distance used for the initial application of the protective coating, although a crinkle finish may be applied in any manner. This crinkle surface creates a less slippery, skid resistant surface. In addition, the additional texture on the surface may have greater insulating properties, and may reduce the surface area of the coating to which human skin contacts, thereby lessening the heat transfer between the surface and skin.

When applying a crinkle finish, the protective coating that was applied in the previous steps is allowed to dry for approximately 15 to 60 seconds. This drying time applicable when using TuffShell™ M25 and may be longer or shorter depending on the actual coating used. Next, the operator moves back from the distance of application of the initial coats (approximately one to seven feet) and applies a light dust coat using a random circular spray pattern to create the crinkle finish. If the operator moves a shorter distance back to apply the dust coat, the particle size in the crinkle finish will be generally smaller (e.g. like 80 grit sand paper). Conversely, if the operator moves a greater distance back to apply the dust coat, the particle size in the crinkle finish will be generally larger (e.g. like 50 grit sand paper). The size of particle is also dependent on the size of the item being sprayed. If a heaver crinkle finish is desired, this step is repeated.

FIG. 3 shows a side view of a structure 150 that was coated according to the method described in FIG. 2. As shown, exposed surface 152 of structure 150 is coated with a protective coating 160 to a first thickness 162. Unexposed surface 154 of structure 150 is coated with a protective coating 160 to a second thickness 164. Preferably, first thickness 162 is greater than second thickness 164, and first thickness 162 is preferably between 25 to 50 mils while second thickness 164 is preferably between 5 and 15 mils.

As shown in FIG. 3, each thickness of protective coating 160 is preferably applied in a generally uniform manner so that each is surface is substantially flat. However, uniform application of each thickness of coating is not required. Thicknesses may vary across each surface of the structure as may be desired. For example, an uneven application of the protective coating may be desired on surfaces that experience uneven wear patterns. For example, steps may experience greater wear toward the middle where foot traffic is expected, and less wear toward the sides of the step. In such a case, the protective coating may be applied more heavily in the middle of the step to add increased durability. In this regard, it may also be desirable to apply no coating on some areas of a surface, such as areas where little environmental wear or use is expected. FIG. 5 shows one example of an uneven application of protective coating on structure 150. In this case, structure 150 is a step. As can be seen in FIG. 5, protective coating 160 is applied at a greater thickness in the middle of the step than at the side.

FIG. 4 shows an example of the crinkle finish. As shown in FIG. 4, crinkle finish 166 is applied on exposed surface 152 of structure 150. However, any surface desired may have the crinkle finish.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and embodiments disclosed herein. Thus, the specification and examples are exemplary only, with the true scope and spirit of the invention set forth in the following claims and legal equivalents thereof.

Claims

1. Playground equipment comprising:

one or more equipment structures; and

a protective coating on at least one of the equipment structures,

wherein the protective coating is a polyurea.

2. The playground equipment of claim 1 wherein the polyurea is TuffShell™ M25.

3. The playground equipment of claim 1 wherein the at least one structure has multiple surfaces including at least one exposed surface and at least one unexposed surface, and

wherein the protective coating is on the at least one exposed surface and the at least one unexposed surface, and the protective coating has at least a first-thickness and a second thickness, the first thickness being on the exposed surface and the second thickness being on the unexposed surface, the first thickness being greater than the second thickness.

4. The playground equipment of claim 3 wherein the first thickness is 20 to 50 mils.

5. The playground equipment of claim 3 wherein the second thickness is 5 to 20 mils.

6. The playground equipment of claim 1 wherein the protective coating has a crinkle finish.

7. The playground equipment of claim 6 wherein the crinkle finish exhibits insulating properties to lower the extent of a temperature increase of the protective coating upon exposure to sunlight.

8. The playground equipment of claim 1 wherein the polyurea is a two-part polyurea.

9. Playground equipment comprising:

one or more equipment structures; and

a protective coating on at least one of the equipment structures,

wherein the protective coating has the following properties: a tensile strength between 1500 and 3000 psi, and an elongation percentage at 25° C. of between 280 and 700 percent.

10. The playground equipment of claim 9 wherein the protective coating has a hardness between 40 and 95 Shore A.

11. The playground equipment of claim 9 wherein the protective coating has a tear strength between 300 and 600 PLI.

12. The playground equipment of claim 9 wherein the protective coating has a thermal shock rating between +400 and −80° F., and a notched Izod impact rating between 65 to 85 inch-pounds/inch.

13. The playground equipment of claim 9 wherein the protective coating is a polyurea.

14. The playground equipment of claim 13 wherein the polyurea is a two-part polyurea.

15. The playground equipment of claim 9 wherein the at least one structure has multiple surfaces including at least one exposed surface and at least one unexposed surface, and

wherein the protective coating is on the at least one exposed surface and the at least one unexposed surface, and the protective coating has at least a first thickness and a second thickness, the first thickness being on the exposed surface and the second thickness being on the unexposed surface, the first thickness being greater than the second thickness.

16. The playground equipment of claim 15 wherein the first thickness is 20 to 50 mils.

17. The playground equipment of claim 15 wherein the second thickness is 5 to 30 mils.

18. The playground equipment of claim 9 wherein at least one of the structures has an exposed surface and the protective coating on the exposed surface has a crinkle finish.

19. The playground equipment of claim 18 wherein the crinkle finish exhibits insulating properties to lower the extent of a temperature increase of the protective coating upon exposure to sunlight.

20. A method of applying a protective coating to a playground equipment structure, the method comprising the steps of:

selecting a structure of the playground equipment to be coated;

applying the protective coating at a first thickness on at least one exposed surface of the structure; and

applying the protective coating at a second thickness on at least one unexposed surface of the structure,

wherein the second thickness is less than the first thickness.

21. The method of claim 20 wherein the protective coating is a polyurea.

22. The method of claim 20 wherein the protective coating is applied by spraying it on the structure.

23. The method of claim 22 wherein the spraying is achieved with a plural component spray system.

24. The method of claim 23 wherein the plural component spray system utilizes an impingement sprayer.

25. The method of claim 20 wherein the first thickness is 20 to 50 mils.

26. The method of claim 20 wherein the second thickness is 5 to 30 mils.

27. The method of claim 20 further including the step of applying a crinkle finish on at least one exposed surface of the structure.

28. The method of claim 27 wherein the crinkle finish is applied by spraying a dust coat onto the structure from a distance greater than the distance from which the protective coating was applied.

29. The method of claim 24 wherein the impingement sprayer has a material hose lines and that further includes the step of heating the material hose lines.

30. The method of claim 29 wherein the material hose lines are heated to approximately 16020 F. to 225° F.

31. The playground equipment of claim 1 wherein the at least one structure has multiple surfaces including at least one exposed surface and at least one unexposed surface, and

wherein the protective coating is on the at least one exposed surface, the protective coating having an uneven thickness across the exposed surface.

32. The playground equipment of claim 31 wherein the uneven thickness is greatest at points along the exposed surface that experience higher amounts of wear.

33. The playground equipment of claim 9 wherein the at least one structure has multiple surfaces including at least one exposed surface and at least one unexposed surface, and

wherein the protective coating is on the at least one exposed surface, the protective coating having an uneven thickness across the exposed surface.

34. The playground equipment of claim 33 wherein the uneven thickness is greatest at points along the exposed surface that experience higher amounts of wear.

35. A method of applying a protective coating to a playground equipment structure, the method comprising the steps of:

selecting a structure of the playground equipment to be coated;

applying the protective coating at an uneven thickness on at least one exposed surface of the structure.

36. The method of claim 35 wherein the uneven thickness is greatest at points along the exposed surface that experience higher amounts of wear.