Wood flooring with sealed joints for truck trailers and containers

Floor boards and wood flooring for truck trailers and containers as well as methods for making and using the same are disclosed. An example wood floor for truck trailers and containers may include a wood member including a plurality of floor boards. Each of the floor boards may include a plurality of wood strips joined together. Opposing side surfaces of the wood strips may be attached together. Opposing end surfaces of the wood strips may be secured together with an end joint. The end joint may include a sealer disposed within the end joint.

TECHNICAL FIELD

The present disclosure pertains to wood flooring. More particularly, the present disclosure pertains to wood flooring for truck trailers and containers.

BACKGROUND

Conventional truck trailers may utilize wood flooring, for example hardwood flooring, because of the desirable characteristics that the flooring may provide the trailer. For example, hardwood flooring may have a desirable level of strength and stiffness. This may give the flooring a long life and increase its wear resistance. Of the known wood floorings, each has certain advantages and disadvantages. There is an ongoing need to provide additional floorings and methods for making and using floorings.

BRIEF SUMMARY

The disclosure provides design, material, manufacturing method, and use alternatives for floor boards and/or wood floors for truck trailers and containers. An example wood floor for truck trailers and containers may include a wood member including a plurality of floor boards. Each of the floor boards may include a plurality of wood strips joined together. Opposing side surfaces of the wood strips may be attached together. Opposing end surfaces of the wood strips may be secured together with an end joint. The end joint may include a sealer disposed within the end joint.

An example method for manufacturing wood flooring for truck trailers and containers may include providing a plurality of wood strips including a first strip and a second strip, forming a first hook in a first end surface of the first strip, forming a second hook in a second end surface of the second strip, dispensing a sealer or joint sealer on the first hook with a dispensing system, and joining the first hook with the second hook to form a hook joint. The sealer may seal the hook joint.

Another example wood floor for truck trailers and containers may include a plurality of floor boards joined together. An underlay may be disposed along a bottom surface of the floor boards. Each of the floor boards may be made from a plurality of wood strips that are joined together. The plurality of wood strips may be bonded along their side surfaces. Opposing end surfaces of the wood strips may be secured together with a hook joint. A sealer may be disposed within the hook joint that seals the hook joint so that the hook joint is essentially impermeable to liquid water and water vapor.

DETAILED DESCRIPTION

FIG. 1is a plan view of an example wood flooring10disposed in a truck trailer12. Although flooring10is illustrated within trailer12, this is not intended to limit the invention as flooring10may be used, for example, with a number of different structures including containers (e.g., shipping and/or freight containers), railroad box cars, and the like, or any other suitable structure. Trailer12may be structurally similar to typical truck trailers. For example, trailer12may have a pair of opposing side walls14and end doors16that can open and close to provide access to the interior of trailer12. In at least some embodiments, flooring10may extend across the width and along the length of the interior of trailer12. Trailer12may have a plurality of support members18(e.g., “I” beams, “C” beams, hat sections, etc.) that each may have an upper flange or surface that crosses the width of trailer12and are spaced along the length of trailer12. In some embodiments, flooring10may be secured to support member18by screws (not shown) or any other suitable fastener, which may penetrate through the whole thickness of flooring10and the upper flange of support members18.

Flooring10may include one or more floorboards or wood members22. Wood members22may take the form of a floor board of flooring component that is made from a suitable hardwood such as oak, maple (including sugar maple), ash, birch, beech, aspen, elm, poplar, apitong, kapur, para agnelim, and the like, or any other suitable hardwood. Hardwoods may be desirable, for example, due to their high strength, stiffness, and excellent durability. Alternatively, some softer woods may also be used, where appropriate.

Each wood member22may include a plurality of wood strips24that are fastened together as shown inFIG. 2. For example, wood strips24may be arranged in a side-to-side and end-to-end manner in order to form wood members22. To manufacture the individual strips24, green (i.e., not dried) wood logs may be cut into lumber using conventional techniques. The lumber may be kiln-dried so that it has an equivalent moisture content of about 2 to 15% (e.g., about 6 to 10%). Alternatively, the lumber may be seasoned or otherwise allowed to dry to the desired moisture content. The dried lumber may be sanded and planed into the desired thickness. For example, the lumber may be sanded and planed so that it has a thickness of about 0.75 to 1.5 inches, or about 1 to 1.25 inches thick. The lumber may also be cut into the desired width, for example, using a ripsaw. For example, the lumber may be cut to have a width of about 0.75 to 2 inches, or about 1 to 1.4375 (i.e., 1 7/16) inches wide. These are just examples.

During the manufacturing of strips24, any wood defects such as knots, cracks and fractures, bark pockets, cavities and holes by insects, decay by fungi, and stains by molds may be removed by cutting off the defects with, for example, a chop saw or suitable automatic cutting system. It can be appreciated that such cutting may alter the length of strips24. It may be desirable for minimum length of wood strips24to be about 12 inches in wood members22. Overall, the average length of wood strips24may be between about three and three and one-half feet.

Both of the opposing ends of each wood strip24may be cut into a square shape with, for example, a tennoner saw. The squared ends of wood strips24may also be further cut so that end structures or “hooks” are formed therein. These hooks allow wood strips24to be attached end-to-end by mating adjacent hooks and forming an end or “hook” joint26as described in more detail below. The depth or size of hook joint26may vary depending on the application. For example, the depth of hook joints26may be about 0.25 to 0.75 inches, or about 0.25 to 0.5 inches, or about 0.375 inches. Alternatively, any other suitable type of joint may be utilized to join together wood strips24. Some examples of the other joints contemplated are disclosed herein.

The suitably prepared wood strips24may also be fastened together side-to-side using any suitable attachment technique. For example, the vertical sides or edges of each wood strip24may be coated with an adhesive by a roller glue spreader. This may help secure wood strips24across the width of wood members22. A suitable adhesive for this securing may include melamine urea formaldehyde, melamine formaldehyde, phenol formaldehyde, emulsion polymer isocyanate (EPI), crosslinking polyvinyl acetate, polyisocyanate, combinations thereof, and the like. The glue-coated wood strips24may be assembled (e.g., both side-to-side and end-to-end) on a conveyor. This may include manual assembly. The hook joints26may fasten together the adjacent ends of strips24to form a continuous slab, in which they are jointed end-to-end in a number of rows (as illustrated inFIG. 1). It may be desirable to control the number of hook joints26per square foot. For example, it may be desirable to have about 5 to 7 hook joints26per square foot on average. The joined collection of wood strips24may be placed into a steam or radio frequency hot press under vertical and cross-direction pressures for curing of the adhesive.

Once strips24are secured together in the desired fashion, the resultant board may be cut to the desired length. For example, the board may be cut to a length of about 56 feet (or more or less depending on the application). Additionally, the board may also be divided into a number of floorboards or wood members22that each has a width, for example, of about 10 to 14 inches or about 12 inches to 12.25 inches. These wood members22may be planed (and/or sanded) to a desired thickness. For example, wood members22may be planed to a thickness of about 1 to 1.5 inches, or about 1.125 inches, or about 1.3125 inches, or about 1.375 inches, etc.

Trailers like trailer12may include a plurality of wood members22joined together to form flooring10. For example, trailer12may include about 6 to 10 wood members22, or about 8 wood members22, or more or less depending on the application. To facilitate the joining of wood members22, shiplaps28and crusher beads30(as shown inFIG. 2), which may be similar to those known in the art, may be machined on to both edges of each wood member22. Shiplaps28may be convenient for installing floorboards on truck trailers by allowing adjacent wood members22to overlap. Crusher beads30may provide spaces between adjacent wood members22, which may protect members22from buckling due to their expansion in wet conditions.

As may be expected, the underside of flooring10may be exposed to the environment during use. For example, the underside of flooring10may be exposed to moisture (e.g., rain, snow, ice, etc.), road debris, dirt, and the like, which may shorten the lifespan of flooring10. Accordingly, wood members22may include an undercoating or underlay32attached to the bottom surface thereof as shown inFIG. 3. In at least some embodiments, underlay32may provide a moisture barrier. Underlay32may be a coating, layer of latex, reinforced underlay (e.g., fiber reinforced plastic), film, or the like.

While sealing or protecting the bottom of wood members22may help extend the lifespan of flooring10, environmental exposure and/or moisture exposure can pose challenges at other portions of flooring10. For example,FIG. 4illustrates a pair of example wood strips24a/24b, each with a hook34a/34bformed therein. Hooks34a/34bmay be brought together mechanically in a mating relationship to define joint26(e.g., “hook” joint26) as shown inFIG. 5. While hook joints26are mechanically joined (in at least some instances with relatively tight tolerances) and can resist ingress of moisture, these bond points may be a location where moisture can access wood members22, potentially leading to degradation of flooring10. In addition, when underlay32is utilized for flooring10, underlay32can delaminate from wood members22along joints including adjacent to hook joints26. The present disclosure provides alternative end or “hook” joints26for wood members22with a sealer or sealing material that may seal joints26so as to provide a suitable moisture barrier, reduce delamination of underlay32, as well as provide additional benefits.

FIG. 6illustrates wood strips24a/24b. In this example, a sealer or sealing material36may be applied to or otherwise disposed on a portion of one of the hooks (in this example, sealer36is disposed along hook34b). When hooks34a/34bare joined together, the sealer36“seals” the hook joint26as shown inFIG. 7.

In at least some embodiments, sealer36may be a thermoplastic polymer adhesive, a thermosetting-based polymeric adhesive, or a combination thereof, and sealer36may be utilized to block a water or moisture path along the profile of hook joint26or other wood joints and avoid the intrusion of moisture into the trailer cargo. Sealer36may bond tightly with wood in each hook joint section. Moreover, the sealer itself may also have an excellent water resistance and meet the requirements for exterior applications of the resultant trailer flooring.

The form and/or material composition of sealer36can vary. In at least some embodiments, sealer36may include a two-part emulsion polymer isocyanate (EPI). According to this embodiment, sealer36may be applied/dispensed using an adhesive dispersing system or an injection die head under a pressure. For the purposes of this disclosure, EPI may be understood to be a two-component adhesive formed by reacting water-based emulsion polymer latex such as styrene-butadiene rubber (SBR) latex, ethylene vinyl acetate (EVA), polyvinyl acetate (PVAc), acrylonitrile butadiene rubber (NBR) latex, acrylic latex, styrene acrylics, or a combination comprising at least one of the above compounds with an isocyanate hardener (or crosslinker). Because the components/ingredients of EPI and their mixing ratios may vary significantly (and various hardeners may be used), the resultant adhesive may be different in molecular weight, pH value, viscosity, set time, open time, curing time, and the like. In at least some embodiments, an isocyanate hardener may include methylene diphenyl diisocyanate (MDI). MDI is an aromatic diisocyanate, existing in three isomers, 2,2′-MDI, 2,4′-MDI, and 4,4′-MDI. Some suitable isocyanate hardeners may include hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), naphthalene diisocyanate (NDI), dodecamethylene diisocyanate, tetramethylene diisocyanate, and the like. Similarly, TDI may exist in two isomers, 2,4-TDI and 2,6-TDI. Other suitable isocyanate hardeners may mainly come from the diisocyanate derivatives such as 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane, 4,4′-diisocyanatodicyclohexylmethane, 4,4′-diisocyanato-2,2-dicyclohexylpropane, 1,4-diisocyanatobenzene, 2,6-diisocyanatodiphenylmethane, 4,4′-diisocyanato-2,2-diphenylpropane, 4,4′-diisocyanatodiphenylpropane-(2,2), p-xylylene diisocyanate, α,α, α′,α′-tetramethyl-m or p-xylylene diisocyanate, combinations thereof, and the like. These are just examples.

EPI may provide a desirable resistance to moisture ingress and may provide desirable heat resistance. EPI is classified as a “Type I” (waterproof) adhesive (or as D4 by European standard EN 204), suitable for exterior applications like truck trailer flooring. Because EPI is a water-based adhesive, it can be easily applied at hook joint26with an adhesive dispensing system (e.g., the dispensing apparatus disclosed herein, an injecting die under a pressure, or the like). In addition, EPI can be easily cleaned off from the dispensing system or the die after application.

In at least some embodiments, the ratio of the two components of the two-part sealer material36can vary. For example, the ratio (e.g., the ratio of the amount of the water-based emulsions of SBR, EVA, and PVAc to the amount of the isocyanate hardener or crosslinker) may be in the range of about 1:1 to 20:1.

In at least some embodiments, sealer36can be a mixture of two or multiple adhesive resins such as EPI/MUF, EPI/MF, EPI/XPVAc, MUF/XPVAc, MF/XPVAc, MUF/XPVAc/EPI, MF/MUF/XPVAc, respectively. Alternatively, EPI may also be blended with a Type II (water resistant) or Type III (not water resistant) adhesive such as urea formaldehyde (UF), PVAc, or the like. The resultant glue mixture should meet the type I adhesive requirement for exterior applications, in which the Type II or Type III adhesive may be 40% or less of the weight of EPI. These are just examples.

In at least some embodiments, sealer36may also include a non-wood filler material and/or non-wood flour. Some examples of non-wood flours that may be included with sealer36include soybean flour, wheat flour, oat hull flour, corn flour, corncob flour, coconut flour, pecan shell flour, starch, and so on. Other wood and non-wood flours (e.g., which can be from ground natural or synthetic fibers) may also be included with sealer36such as wood fiber, cellulose fiber, reeds, bamboo, papyrus, jute fiber, hemp fiber, kenaf fiber, flax seed fiber, sugarcane bagasse fiber, sisal fiber, abaca fiber, henequen fiber, wheat stalk/chaff, corn stalk, sorghum stalk, cotton stalk, rice straw, wheat straw, oat straw, barley straw, rye straw, flax straw, grass straw, coconut coir, rice husks, peanut hull, cotton linters, Esparto grass, sabai grass, pulp, nitrocellulose, and the like. The mesh size for the non-wood filler material and/or wood flours may be in the range of about 20 to 200 meshes. The amount of non-wood filler material and/or wood flours included with sealer36, if used at all, may be about 1 to 50% or less by weight or about 2 to 44% or less by weight.

In at least some embodiments, inorganic or mineral fillers may also be included to adjust the viscosity of adhesive fillers. Such materials may desirably increase the wearing resistance and hardness of the resultant adhesives. Moreover, the inclusion of fillers may help reduce the cost of sealer36. Some examples of suitable inorganic fillers may include calcium carbonate (CaCO3), magnesium carbonate (MgCO3), silicon dioxide (SiO2), aluminum oxide (Al2O3), sodium oxide (Na2O), potassium oxide (K2O), calcium oxide (CaO), iron oxide (Fe2O3), magnesium oxide (MgO), titanium dioxide (TiO2), and the like. The inorganic fillers may also include mixtures of the above inorganic compounds. The examples may include talc [Mg3Si3O10(OH)2], kaolin [Al2Si2O5(OH)4], gypsum, clays, and the like. In addition, some inorganic minerals like Fe2O3and TiO2may also be used as a colorant or pigment in adhesives. The amount of inorganic fillers used for sealer36may be about 1 to 20% or so by weight (e.g., 1 to 10% or so by weight). These are just examples.

In at least some embodiments, sealer36may include a relatively small fraction of pH buffer, which may be used to maintain the pH value of EPI to be 6.0 to 8.5 or so. Some examples of commercially available pH buffer solutions may include 2-(N-morpholino) ethanesulfonic acid (MES), 3-(N-morpholino)propanesulfonic acid (MOPS), 3-{[tris(hydroxymethyl)methyl]amino}propanesulfonic acid (TAPS), 3-[N-Tris(hydroxyl methyl) methylamino]-2-hydroxypropanesulfonic acid (TAPSO), acetic acid, citric acid, dimethylarsinic acid (Cacodylate), dipotassium phosphate (K2HPO4), disodium phosphate (Na2HPO4), monopotassium phosphate (KH2PO4), monosodium phosphate (NaH2PO4), N-tris(hydroxymethyl)methylglycine (Tricine), piperazine-N,N′-bis(2-ethanesulfonic acid) (PIPES), sodium acetate, sodium citrate, saline sodium citrate (SSC), tris(hydroxymethyl)methylamine (Tris), and the like. These are just examples. The pH buffers used for sealer36generally are selected so that they do not react with the isocyanate catalyst and/or do not interfere with the crosslinking reaction of EPI.

In some of these and other embodiments, a colorant or pigment such as carbon black, SYN-OX HB-1034 and/or HB-1094 (commercially available from Hoover Color, Hiwassee, Va.), and titanium dioxide (commercially available from Lansco Colors, Pearl River, N.Y.) may be included. Other colorants that may be used may include those commercially available from BASF (Florham Park, N.J.) including CIBA CROMOPHTAL Blue 4GNP, CROMOPHTAL Brown 5R, IRGALITE green GFNP, IRGALITE blue BLPO, IRGALITE black 2B-LN, or the like), combinations thereof, or the like. The colorant amount may be about 0.1 to 6% or so by weight (e.g., 0.1 to 4% by weight). These are just examples.

Sealer36may also be selected so as to have additional features and/or characteristics. For example, in at least some embodiments, sealer36may have any overall viscosity in the range of about 1,000 to 1,200,000 cps at room temperature. The open time for sealer36(e.g., the amount of time that sealer36is allowed to set before bringing hooks34into contact) may be in the range of about 10 to 120 minutes and the set time for sealer36(e.g., the amount of time that sealer36is allowed to set after bringing hooks34into contact) may be in the range of about 3 to 60 minutes. These are just examples.

FIG. 8illustrates an example method for forming sealed hook joints26. For example, a dispensing apparatus38may be used to dispense sealer36onto wood members22(e.g., along or otherwise adjacent to hooks34). Other dispensing systems may also be used. For example, an injection die may be used as a dispensing system for dispensing sealer36onto wood members22. Other suitable dispensing systems may also be utilized.

In at least some embodiments, while performing the process, a user can monitor progress and/or alter the process at a user dashboard42. Dispensing apparatus38may include one or more structures such as pumps/motors40a/40b. Dispensing apparatus38may include one or more pails or tanks44a/44b(e.g., of any suitable capacity, depending on the volume required) that can be used to supply sealer36. In embodiments that utilize EPI as sealer36, pail44amay include an isocyanate hardener. Pail44bmay include an emulsion of SBR latex, EVA, PVAc, NBR latex, acrylic latex, styrene-acrylics, or a combination comprising at least one of the above compounds, and the like. It can be appreciated that in embodiments where sealer36is a one-part adhesive material, dispensing apparatus38only needs to include a single supply pail.

Motors40a/40bmay pump or otherwise be used to transport the materials disposed in pails44a/44balong outlets or hoses46a/46b, through valves50a/50b, and to a mixer48. Here, the components of sealer36can be mixed or otherwise readied for dispensing onto hook34of wood strip24. A conveyor or transporting structure54may be used to move or transport each wood strip24to a suitable position so that the sealer36can be dispensed through a dispensing head52and onto, for example, a “valley” of hook34. In at least some embodiments, a bead or suitable quantity of sealer36(e.g., in the range of about 0.05 to 15 grams, or about 0.1 to 10 grams, or about 0.2 to 5 grams) is dispensed onto the valley of hook34on wood strip24. The amount of sealer36dispensed may be adjusted so as to reduce the amount squeezing out from joint26. A pair of wood strips24can be joined together by bringing their respective hooks34into contact. Once joined, sealer36can be cured (e.g., with heat) or otherwise allowed to dry or cure under room conditions so as to seal joints26. Other processes may also be utilized including bonding adjacent wood strips24along their opposing side surfaces.

While sealed hook joints26are disclosed herein, the present disclosure is not intended to be limited as a variety of joints (e.g., end joints) are contemplated.FIGS. 9-15illustrate some examples of the end joints contemplated. For example,FIG. 9illustrates wood strips124a/124bwith hooks134a/134bjoined in hook joint126. Sealer136is disposed along a portion of hook joint126. In this example, hook joint126may be described as partially sealed [e.g., where a bottom and/or top portion of hook joint126(i.e., the vertical walls adjacent to hooks134a/134bof wood strips124a/124b) is sealed at joint126to house sealer136], while sealer136may be expanded to some area of the middle portions of wood strips124a/124bat hooks134a/134bduring the assembly and hot pressing processes.FIG. 10illustrates wood strips224a/224bwith hooks234a/234bjoined in hook joint226. Sealer236is disposed onto a portion of hook joint226. In this example, hook joint226may be only sealed in the middle portion (e.g., where the middle portions of wood strips224a/224badjacent to hooks234a/234bof hook joint226are bonded together with sealer236). In addition, some of the sealer236may be squeezed out from the middle portions of wood strips224a/224badjacent to hooks234a/234bof hook joint226and further fills some area of the vertical walls at hooks234a/234bdue to the vertical and cross-section pressure by a hot press.

Additional joints can be seen inFIGS. 11-15. For example,FIG. 11illustrates wood strips324a/324bjoined with a butt joint326. Sealer336is disposed at joint326, which seals joint326.FIG. 12illustrates wood strips424a/424bjoined with a scarf joint426. Sealer436is disposed at joint426, which seals joint426.FIG. 13illustrates wood strips524a/524bjoined with a lap joint526. Sealer536is disposed at joint526, which seals joint526.FIG. 14illustrates wood strips624a/624bjoined with a finger joint626. Sealer636is disposed at joint626, which seals joint626.FIG. 15illustrates wood strips724a/724bjoined with a gear tooth joint726(i.e., a modified finger joint). Sealer736is disposed at joint726, which seals joint726. In addition, variations and/or modifications to these joints are contemplated. For example, in embodiments that utilize hook joint26(or a modified hook joint) and finger joint626(or gear tooth joint726), respectively, any suitable number of end joint/modified end joint may be utilized without departing from the spirit of the invention. Other variations in shape, number, arrangement, and the like are also contemplated.

EXAMPLES

The invention may be further clarified by reference to the following Examples, which serve to exemplify some of the preferred embodiments, and not to limit the invention in any way.

Preparation of Floorboard Samples

Nine oak floorboard samples were prepared for testing. In each sample, three oak strips (2.8 inches wide by 10.5 inches long by 1 5/16 inches thick) were joined together along their side surfaces with MUF. A hook joint was disposed in the center strip. Sample oak floorboards were prepared using either no sealer at the hook joint or the example sealer from Examples 1 to 5 at the hook joint for testing. When utilizing the sealer, the preparation also included disposing the example sealer36at the hook joints, allowing the sealer36to set for 10 minutes under room conditions, and then the floorboard assemblies were pressed in a lab press at a temperature of 300° F. for 10 minutes. After pressing, the resultant floorboard samples were placed at room temperature for 72 hours.

Water Penetration Test

During the water penetration test, a pressure vessel was mounted with its clamp on the hook joint of an oak floorboard sample. Water was added into the chamber of the pressure vessel. The chamber was closed tightly with a valve. Compressed air connected to the chamber was then turned on. The water pressure was gradually increased from 0 psi until it reached the maximum pressure of 40 psi. The test was stopped when the hook joint started leaking. All the tested samples were further evaluated for wet shear performance (disclosed below).

The sample oak floorboards using the example sealer material from Examples 1 to 5 withstood (e.g., did not leak) water pressures of 40 psi. Conversely, unsealed hook joints leaked immediately at 0 psi.

Hook joint sections of standard oak trailer flooring in the market normally have a water leaking rate of 90% or higher. By using the example sealers, the water leaking rate can be significantly reduced (e.g., the leak rate may be reduced and may approach 0%).

Wet Shear Test

The wet shear performance of the sample oak floorboards were evaluated in accordance with the Fruehauf industry standard. After the wet penetration test, all of the samples were cut into 2-inch long shear blocks, in which hook joint was located at the center of each sample. The wet shear block samples were initially immerged in water (at room temperature) and soaked for 48 hours. The samples were then dried in an oven at a temperature of 140° F. for 8 hours and then subsequently soaked in water for another 16 hours. These cycles were then repeated a second time. Subsequently, all of the shear block samples were removed from water and placed at room temperature for one hour prior to the performance of a shear test with a universal test machine.

The sample oak floorboards with the example sealer had an average wet shear strength higher than those without any sealer. The sample oak floorboards utilizing the sealer from Example 3 were slightly higher in shear strength than those without any filler, while the sample oak floorboards utilizing the sealer from Example 1 improved the wet shear strength of the resultant floorboards by 17% (when compared to those without the sealer). The results of the wet shear testing data is presented in Table 1.

All the sample floorboards with the example sealers exceed (e.g., greatly exceed) the minimum value of 525 psi required by the Fruehauf industry standard for wet shear strength.