Wooden post with protective coating and method for making same

Abstract

A protected wooden post having a coating of a hardened protective material that surrounds the peripheral surface of the post to protect the wood thereunder from marring and abrasion, typically from the use of a nylon string trimmer to trim grass and weeds from around the base of the embedded post. A hardenable protective coating can be applied to a wooden post, either before the wooden post is installed into the ground, or after the wooden post is embedded into the ground. Typical wooden posts include mailbox posts, swing set posts, fence posts and telephone poles. The hardened protective coating typically includes a UV protector to diminish the effect of UV light from sunlight on the integrity of the protective coating material.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claism the benefit of copending U.S. Provisional Patent Application No. 60/579,010, filed Jun. 12, 2004.

BACKGROUND

The United States government has operated a postal service since 1775 when the Continental Congress named Benjamin Franklin the first Postmaster General. Rural free delivery service to individual residences in the rural America first began in 1896, and by 1908, much of America received its main daily by postal delivery.

Presently, a significant proportion of the population receives the U.S. mail in residential mail boxes positioned on or near the resident's property and along the side of the road. There are a variety of mail boxes in use, but the majority of them are shoebox-sized or larger containers that are affixed to the top end of an upright support, such as a wooden post. The bottom end of the support is buried into the ground to secure the mailbox from swaying and falling over.

Many residents position the mailbox in the lawn along side the road. In the course of cutting the grass, the resident or a lawn care professional will use a trimming device to trim grass growing close to the base of the mailbox post that can not cut with a lawn mower. A typical grass trimming device has an electric or gasoline-operated motor that drives a spool hub at an opposite end via an elongated shaft. The hub carries a length of flexible trimming string, a portion of which projecting outwardly from hub 20. As the motor is operated, the hub rotates at great speed. The outwardly-projecting section of line is swung in a circle about the axis of the shaft, whereby it will contact and cut off grass or other material in its path. Examples of such devices are shown in U.S. Pat. Nos. 2,708,335; 3,006,421; 3,608,291; 4,200,978; and 4,584,771.

The flexible plastic string used in the grass trimmers is designed and selected for durability. The string typically is made of a flexible plastic with a high hardness that resists wear and breaking when striking the earth, asphalt, concrete, stones and other hard or sharp articles. Some grass trimming strings are designed with star-shaped profiles that provide the outer surface with edges that improve the cutting function.

The strength, durability and design of the flexible plastic string also causes damage and wear along the base of wooden mailbox posts when trimming grass close to the base. After repeated grass cutting and trimmings, the periphery of the base of the wooden post can experience significant wear. As many mailbox wooden posts are made of pressure-treated wood, the wearing away of the outer wood surface along the base exposes the wood in toward the interior which tends to have less of the water-resistant chemicals. With time, the wood along the worn base of the wooden post begins to deteriorate rapidly with additional wear and water. In certain northern regions, snow that is propelled from a roadway by a snowplow can impact and snap off the mailbox post at its base.

At the same time, lawn mowers housings often strike and gouge the base of the wooden post in the operator's effort to cut the grass as close as possible to the post.

Therefore, a need exists for a means for preventing the wear of the base of wooden posts by grass trimmers and lawn mowers.

SUMMARY OF THE INVENTION

The invention is a protected wooden post for positioning within the ground to an intended depth, comprising a wooden post having a first embedded end, a second upper end, and a ground-level position intermediate the first and second ends, and a hardened protective coating covering the peripheral surface of the wooden post and extending from proximate the ground-level position toward the second end. The wooden post can include a post made from pressure-treated wood.

The invention also relates to a method of protecting the base of a wooden post from wear and abrasion, prior to or after positioning into the ground, comprising the steps of: applying a hardenable protective material to cover the peripheral surface along the length of the post, extending from proximate a ground-level position intermediate the first and second ends of the post, toward the second end; and hardening the protective material into a protective coating.

The wooden post can include, but is not limited to, a mailbox post, a fence post, a swing or play set post, a deck support post, and a telephone pole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a wooden post, used as a mailbox post, having a protective coating that covers a portion of the post intermediate the ends.

FIG. 2 shows a wooden post positioned within the ground and having a protective coating covering the periphery of the post proximate the ground level.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an improved wooden post 60 of the present invention, typically a four-sided post of square or rectangular cross section, having a length defined by an upper end 64 and an embedded end 62 intended to be embedded into the ground to support the upper end 64 of the post 60 in an upright or tilted position. Such a post is typically used for the mounting of a mailbox 100, as shown in FIG. 1, and for other uses including fence posts and wooden play frames and swing sets. Intermediate the embedded end 62 and upper end 64 of the post is a ground-level position 70, where the distance from the ground-level position 70 to the embedded end 62 approximates the depth that the post would be embedded into the ground in an intended use for the wooden post. The wooden post 60 comprises a protective coating 10 that typically covers the outer peripheral surface of the wooden post 60. The protective coating typically extends from proximate the ground-level position 70, toward the upper end 64. The protective coating can also extend from proximate the ground-level position 70 toward the embedded end 62. Preferably, the coating 10 extends from below the ground-level position 70 (that is, toward the embedded end 62) toward the upper end 64. Typically, the protective coating covers a length of the post of from about 5 cm to about 50 cm, more typically from about 10 cm to about 30 cm, and extends from a position 72 about 5 cm to about 20 cm (or more) above the ground-level position 70 (that is, toward the upper end 64), toward the first end 62 to a position 74 about 2 cm to 15 cm, or more, below the ground-level position 70. In other embodiments, the protective coating can extend from above the ground-level position 70, to the very first end of the embedded end 62.

The protective coating is typically formed from a hardenable or curable liquid protective material that is applied as a liquid coating onto the surface of the wooden post to adhere directly thereto. The liquid coating hardens or cures into the hardened, protective coating. The hardenable liquid material can harden or be hardened by a variety of means, including solvent evaporation, melt cooling, and chemical reaction. A protective coating typically hardens or cures, after application of the liquid coating, into a dense, solid, and adherent coating.

The protective coating typically comprises a binder that provides its hardness, uniformity and coherence. The binder ability to form a dense, tight film is directly related to its molecular size and complexity. Binders that have the highest molecular weight can form films by the evaporation of the vehicle, while binders with smaller molecular weight will generally be chemically reacted in situ. Non-limiting examples of the binders can be selected from the group consisting of: oxygen-reactive binders, including alkyds, epoxy esters, urethane alkyds, and silicone alkyds; lacquers, including polyvinyl chloride polymers, chlorinated rubbers, acrylics, and bituminous materials (e.g., tar); heat conversion binders, including hot melt materials, organisols and plastisols; co-reactive binders, including epoxies and polyurethanes; condensation binders; coalescent binders including latex and poly-fluoroethylene/vinyl ether (FEVE); and inorganic binders, including post-cured silicates, self-curing water silicates, and self-curing solvent-based silicates.

The protective material can be transparent, translucent, or opaque, and can have a natural or other color.

An optional component of the protective coating is an opacifying agent. One type of opacifying agent is a pigment. A pigment is essentially a dry powder that is insoluble in the binder and solvent medium, and that consequently needs to be mixed in by a dispersion technique. Other types of opacifying agents can include titanium dioxide, talc and silica powders. The opacifying agent can be naturally occurring or a man-made organic compound. The opacifying agent can contribute several properties, including color, film reinforcement, sag control, increased coverage, gloss control, and adhesion.

Another optional component of the protective coating is a UV absorber or blocking compound, which can diminish the effect of UV light from sunlight on the integrity of the protective coating material. UV absorbers suitable for use in the protective coating are well known and used widely in industrial coatings. Non-limiting examples of UV absorbers include benzophenone and benzotriazole.

The protective coating typically comprises one or multiple solvents. The choice of solvents influences viscosity, flow properties, drying speed, spraying or brushing characteristics, and gloss. There is no universal solvent for protective coatings, the best solvent in one system being often impractical for another. Asphalts, for example, can be readily dissolved by hydrocarbons but are insoluble in alcohols. One of the most serious problems associated with coatings is the wrong choice of solvent since it can severely affect the curing and adhesion characteristics of the final coating. Typical solvents include: aliphatic hydrocarbons or paraffins such as naphta or mineral spirits are typically used with asphalt, oil and vinyl based coatings; aromatic hydrocarbons, such as toluene, xylene or some of the higher boiling homologs, which are typically used with chlorinated rubbers, coal tars and certain alkyds; ketones such as acetone, methyl ethyl ketone, methyl iso-butyl or amyl ketone and many others, which are used with vinyls, some epoxies and other resin formulations; esters such as ethyl, n-propyl, n-butyl or amyl acetates, which are used commonly as latent solvents (a type of solvent that just swells the binder at room temperature) with epoxy and polyurethane formulations; alcohols such as methyl, propyl, iso-propyl or butyl alcohols and cyclo-hexanol, which are good solvents for highly polar binders such as phenolics; ethers and alcohol ethers, such as ethyl ether, which are excellent solvents for some of the natural resins, oils, and fats; and water, which with recent regulations to reduce the emission of volatile organic compounds (VOCs) produced by organic solvents, has been forcing the coating industry to reconsider the applicability of water as a solvent.

The improved wooden post is used to protect the base of the embedded post from wear from both natural causes and from mechanical abrasion. For example, mechanical abrasion can be caused by the use of mechanical string trimmers that use a nylon string to cut grass and weeds around the base of the embedded post. Typically, the protective material used to form the protective coating is selected to have a hardness that is greater than the hardness of the plastic used for the trimming string. Typical protective materials include curable epoxy compositions as described in U.S. Pat. Nos. 4,383,090, 4,177,173, 3,978,151, 6,573,309, 6,084,039, 4,170,613, 4,172,157, 4,377,457, and 4,424,252, all incorporated herein by reference. Use of the layer of protective materials proximate to the based of the embedded post serves to prevent wear of the outer wood surface along the base, which in time could cause the worn base to deteriorate and weaken.

A method of manufacturing a protected wooden post, such as the one shown in FIG. 1, comprises the steps of: providing a wooden post having a first embedded end, a second upper end, and a ground-level position intermediate the first and second ends; applying a liquid coating of a hardenable protective material to the peripheral surface of the post, extending from proximate the ground-level position and toward the upper end; and hardening the liquid coating into the hardened protective coating. The liquid protective material can be sprayed on, brushed on, or roller-applied onto the post. The applied liquid protective coating is then hardened, or allowed to harden, into the hardened protective coating. The hardened protective coating is not tacky or soft, and is typically sufficiently hard and durable to resists mechanical wear. The step of hardening can include allowing the material to harden with time due to solvent evaporation, chemical reaction, and temperature change. Typically, the hardenable protective material is applied at a thickness of from about 0.5 mm to about 3 mm. The material can be uniformly or non-uniformly applied, or intermittently applied to the outer periphery of the post.

The invention also includes a method of applying, as described above, the liquid coating of the hardenable protective material to the base of the wooden post, such as the post 60 shown in FIG. 2, while embedded or positioned within the ground 80, and allowing the hardening of the liquid coating into the hardened protective coating 10. Typically the hardenable protective coating 10 has been applied from a position 72 above the ground-level position 70, down to proximate the ground-level position 70 of the post 60. It is not necessary that the coating be applied completely to the level of the ground; by “proximate” means above the ground-level position, to the ground-level position, or below the ground-level position. The method and the protected post of the invention can prevent marring and damage of the underlying wood of the post near the base when grass 66 or other vegetation is trimmed using a string trimmer.

EXAMPLES

Example 1

A 7-foot long, 6-inch by 6-inch pressure-treated wooden post is provided, and a fresh mixture of an epoxy resin and polymercaptan amines is applied around the peripheral surface of the wooden post to a thickness of about 1 mm, and along a 25 cm length, starting at a distance of from about 30 cm from a first embedded end of the post, toward the second upper end. The protective material begins to harden about five minutes after the mixture is formed, and is typically fully cured and hardened after 10 minutes more. The protected wooden post can then be inserted into the ground, wherein about 10 cm of the hardened protective layer extends about ground level. When a string trimmer device is used to trim grass from around the mailbox post, the periphery of protective material resists scarring or tear by the nylon trimmer string, and protects the wooden post thereunder from the same.

Example 2

An existing vertical mailbox post was provided, which had been embedded into the ground in a grass lawn. The mailbox post was a pressure-treated wooden post, having a height of about 5 feet and a 6-inch by 6-inch cross section. The base of the mailbox post near the ground was substantially free of damage to its outside peripheral surface. A fresh mixture of an epoxy resin and polymercaptan amines was formed and applied with a 2-cm wide plastic bristle brush, around the periphery of the wooden post to a thickness of about 1 mm, from near the ground level to a height of about 15 cm. The epoxy mixture began to harden about five minutes after the mixture was formed, and fully cured into a protective material after 15 minutes. When a string trimmer device was used the next day to trim grass from around the mailbox post, the periphery of protective material resisted scarring or tear by the nylon trimmer string, and protected the wooden post from the same. Repeated use of the nylon string trimmer to trim grass from around the base of the mailbox post resulted in no loss in the integrity of the epoxy protective coating, and protected the surface of the wooden mailbox post from scratches, scarring, and tears in the wood.

Example 3

The wooden legs of an A-frame swing set are coated with a hardenable mixture of epoxy resin and polymercaptan amine, along the lower length of the legs, and the mixture is allowed to harden. The legs are coated so that once the legs are installed into the ground, the hardened coating extends above the ground level for 15-20 centimeters. Grass and weeds that grow around the swing set legs can be trimmed with a nylon string trimmer, which cuts the grass and weeds, but strikes only the hardened coating, thereby not damaging the underlying wooden leg.

Example 4

Similar procedures and results are obtained as in Examples 1 and 2 with a telephone pole, fence posts, and deck support posts.

Claims

1. A protected wooden post for positioning within the ground to an intended depth, comprising a wooden post having a first embedded end, a second upper end, and a ground-level position intermediate the first and second ends, and a hardened protective coating covering the peripheral surface of the wooden post and extending from proximate the ground-level position and extending toward the second end.

2. The protected wooden post according to claim 1 wherein the wooden post is selected form the group consisting of a mailbox post, a fence post, a swing or play set post, a deck support post, and a telephone pole.

3. The protected wooden post according to claim 1 wherein the protective coating comprises a binder that is selected from the group consisting of: oxygen-reactive binders, including alkyds, epoxy esters, urethane alkyds, and silicone alkyds; lacquers, including polyvinyl chloride polymers, chlorinated rubbers, acrylics, and bituminous materials; heat conversion binders, including hot melt materials, organisols and plastisols; co-reactive binders, including epoxies and polyurethanes; condensation binders; coalescent binders; and inorganic binders, including post-cured silicates, self-curing water silicates, and self-curing solvent-based silicates.

4. The protective wooden post according to claim 1 wherein the protective coating extends from below the ground-level position, to above the ground-level position and toward the upper end.

5. The protected wooden post according to claim 1 wherein the protective coating covers a length of the post of from about 5 cm to about 50 cm, and extends from a position about 5 cm to about 20 cm above the ground-level position, to a position about 2 cm to 15 cm below the ground-level position.

6. A method of protecting the base of a wooden post from wear and abrasion, comprising the steps of: applying a hardenable protective material to cover the peripheral surface along the length of the post, extending from proximate a ground-level position intermediate the first and second ends of the post, toward the second end; and hardening the protective material into a protective coating.

7. The method according to claim 6 wherein the hardenable protective material is applied to the wooden post prior to positioning the wooden post into the ground.

8. The method according to claim 6 wherein the hardenable protective material is applied to the wooden post while positioned in the ground.

9. The method according to claim 6 wherein the wooden post is selected form the group consisting of a mailbox post, a fence post, a swing or play set post, a deck support post, and a telephone pole.

10. The method according to claim 6 wherein the protective coating comprises a binder that is selected from the group consisting of: oxygen-reactive binders, including alkyds, epoxy esters, urethane alkyds, and silicone alkyds; lacquers, including polyvinyl chloride polymers, chlorinated rubbers, acrylics, and bituminous materials; heat conversion binders, including hot melt materials, organisols and plastisols; co-reactive binders, including epoxies and polyurethanes; condensation binders; coalescent binders; and inorganic binders, including post-cured silicates, self-curing water silicates, and self-curing solvent-based silicates.

11. The method according to claim 6 wherein the hardenable protective material is applied from below the ground-level position, to above the ground-level position and toward the upper end.

12. The method according to claim 6 wherein the hardenable protective material is applied to cover a length of the post of from about 5 cm to about 50 cm, and to extend from a position about 5 cm to about 20 cm above the ground-level position, to a position about 2 cm to 15 cm below the ground-level position.