JPH04803B2 - - Google Patents

Description

[Detailed description of the invention]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to articles formed from flake-like wood particles, and more particularly to such articles having non-planar portions, such as material handling pallets and the like. Considerable efforts have been made to develop techniques for forming articles containing non-planar parts from inexpensive residue and surplus wood. One area of particular interest in utilizing such wood is in the production of material handling pallets that have at least the same strength, durability and other desirable properties as standard pallets constructed from sawn lumber. The finely ground wood is mixed with a suitable resinous binder, such as a synthetic thermosetting resin, the mixture is formed into a multilayer mat, the mat is then compressed between heated platens, and the wood particles are It is well known to make flat or substantially flat structural boards, ie so-called particle boards, from pulverized wood by bonding them together. This type of method is covered by a U.S. patent
3164511, 3391233 and 3940230. The forming of pallets and other articles containing non-planar portions presents problems that are little or no related to the manufacture of flat or substantially flat particle board. For example, one difficulty that arises in forming pallets is converting a plurality of hollow legs with acceptable crushing strength from a substantially flat mat of wood particles without adversely affecting the strength of the decking members or legs. , there is a need for drawing. Finally, methods of the type described above for making granular particle board have not been previously used for making pallets or other similar articles from wood particles. U.S. Patents 3104085, 3359929 and 3611952
In one prior art method of forming pallets from wood particles, as exemplified by Wood Fibers, the wood fibers are made into a pulp slurry. This pulp slurry is
It typically also contains a resinous binder or other suitable binder. Introduce this slurry into the mold,
Most of the water is removed therein, such as by compression, application of vacuum or positive pressure. This wet molded pallet is transferred to a heated mold and dried under conditions of high pressure and temperature to facilitate the removal of water and, when containing a binder, to cure it. do. When a binder is not included in the slurry, the dried pallets are usually soaked in a resin-containing solution to strengthen and make them waterproof. This prior art method involves several expensive processing steps, and the pallets produced thereby do not have acceptable strength properties or durability for many applications. Promoted in the United States under the trademark “WERZALIT” and U.S. Patents 3,146,285 and 3,354,248
In another prior art method of forming pallets from wood particles, as exemplified by A preform is formed with the binder partially cured or not cured. The preform is transferred to a heated press or mold in which it is compressed to its final size and shape at elevated temperatures to fully cure the binder. This method is
Due to the degree to which the starting material must be finely ground, the amount of binder required to bind the relatively small wood particles together, the capital investment for different presses, and the operating costs associated with the multiple processing steps. , relatively expensive. The main object of the present invention is to provide a material handling pallet-like material handling pallet having a main body and a non-planar portion displaced from this body, the main body and the non-planar portion being molded as an integral unit from low cost wood. , to provide goods. Another object of the present invention is to provide a pallet that is formed from low cost wood and has strength and handling characteristics that are at least comparable to standard pallets made from sawn rods. Another object of the invention is to provide a simplified method of forming such pallets and other articles having non-planar portions from low cost wood particles. Still another object of the present invention is to provide such a method that does not require shaping of a preform before shaping to final dimensions and does not require pulverized wood particles. Other objects, aspects, and benefits of the invention will become apparent to those skilled in the art from the following detailed description, drawings, and claims. A pallet provided by the present invention includes a deck member having a main plane and a plurality of hollow leg members integrally projecting from the deck member, each leg member being spaced apart from the deck member. and a bottom wall and side walls, the side walls sloping outwardly from the bottom wall toward the decking member. The deck members and leg members are formed as an integral unit from a layered mixture of a resinous particle board binder, such as a thermosetting resin, an organic polyisocyanate, or a mixture thereof, and flake-like wood particles; has an average length of about 1.25 to about 6 inches (approx.
3.18 to approx. 15.24 cm), and the average thickness is approx. 0.005 to approx.
about 0.075 inches (about 0.013 cm to about 0.191 cm), and has an average width of less than about 3 inches (about 7.62 cm) and a shorter than average length. Each layer of wood particles forms at least a deck member lying substantially flat in a plane that is generally parallel to the major plane, and the wood particles therein are randomly oriented. The sidewalls of the leg members may extend at an angle of less than about 78° with respect to the major plane of the deck member and have an average thickness that is about 70-110%, preferably about 80-85% of the average thickness of the deck member. can have. The pallet may contain from about 2 to about 15 weight percent binder, based on the dry weight of the wood flakes, and optionally from about 0.5 to about 2 weight percent wax to impart waterproof properties. Organic polyisocyanate is
Alone and in combination with urea-formaldehyde, it is a preferred binder. In a preferred method, wood flakes are mixed with a resinous particle board binder and the resulting mixture or composition is placed in an open mold comprising two separable parts defining a mold chamber having the shape of a pallet. or deposited as a loosely felted layered mat on one part of the press, closing the mold and applying pressure to the mat to substantially compact it to the desired shape and size of the pallet; Join the wood flakes together. In one embodiment, a mat of substantially uniform thickness is formed outside the mold, according to which the flakes in each layer lie substantially flat and are randomly oriented. , and this mat is placed between the M die and the F die of the mold. In other embodiments, the mat is formed outside the mold as described in the previous section, and a mound of the composition is added above the mat at a location corresponding to the leg-forming cavity of the F die. In other embodiments, the leg forming cavity of the F die is first substantially filled with the composition and the mat is then placed between the M die and the F die. In yet other embodiments, the mat is formed directly on the F-die or a remote caul plate having a shape that matches the F-die and subsequently placed over the F-die. This technique and the techniques described in the two previous sections are particularly advantageous for forming leg members having lengths or depths up to about 5 inches (12.7 cm) or more. The present invention generally relates to articles, particularly support members, comprising a main body having a major plane and a non-planar portion displaced from the major plane, both of which are formed as an integral unit from wood flakes. The invention has particular application to material handling pallets and will be described with respect thereto. 1 and 2, a pallet 10 is illustrated. The pallet 10 has a substantially uniform wall thickness and a flat upper surface 1 that serves as a supporting plane.
4 and includes a generally flat rectangular deck member 12 having a diameter of 4. A plurality (e.g., nine) of hollow leg members 16 act as support pads for the pallet.
protrudes downward from the deck member 12. In the particular structure illustrated, each leg member 16 (second
Figure 1) includes a bottom wall 18 having a flat bottom plane 20 and two opposing pairs of flat side walls 22 and 24. The bottom surface 20 of the bottom wall 18 is connected to the decking member 12
spaced a sufficient distance from the lower surface of the deck member to permit entry of the teeth of the forklift below the deck member. Decking member 12 and leg member 16 are molded as a unitary unit from a mixture of a suitable resinous partailboard binder and flake-like wood particles, as described below. The side walls 22 and 24 of the leg members 16 are sloped or tapered to facilitate shaping and also allow for the interlocking of several pallets to minimize the space required for transportation and storage. . In the particular construction illustrated, side walls 22 and 24 are substantially planar and leg member 16 has the general shape of an inverted frustoconical hollow pyramid. If desired, the leg members 16 can be formed to have other suitable cross-sectional shapes, such as the shape of an inverted truncated hollow cone. FIG. 3 diagrammatically illustrates the various steps of the method of the present invention for making pallets 10 from inexpensive residual and surplus wood. The method broadly consists of grinding small logs, branches or rough pipe material into flake-like particles, drying the wood flakes to a predetermined moisture content, and classifying the dried flakes to a predetermined moisture content. wood material particles of a given size, a predetermined amount of a suitable resinous particle board binder, and optionally a liquid wax composition.
Combined with the dried and sized flakes, the resulting mixture or composition of binder, wax and wood flakes is formed into a loosely felted layered mat (single or multi-layered) which is shaped into the desired shape of the pallet. The mold is placed in an open mold or press containing separable M and F dies defining a mold chamber with a mold chamber, the mold is closed, and sufficient pressure is applied to the mat to cause it to form a substantial portion of the pallet. the pallet to the desired shape and size, and the perimeter of the pallet is trimmed to the desired final dimensions using a power saw or the like. The wood flakes used can be made from various species of hardwoods and softwoods suitable for use in making particle board. Typical examples of suitable wood are:
These are poplar, maple, oak, balsam fir, pine, fir, fir, hemlock, false acacia, beech, birch and mixtures thereof. Suitable wood flakes can be produced by a variety of conventional techniques. In certain methods, wood flakes are manufactured by one of two different techniques. In the technique illustrated in the top left part of FIG. 3, pulpwood grade logs, or so-called roundwood, are flaked in one operation using a conventional roundwood flaker. In the technique illustrated in the upper right portion of FIG. 3, logs, wood cutting residues, or whole trees are first cut with a 2- to 6-inch (2- to 6-inch) Cut the fingerlings into fingerlings (5.08 to 15.24 cm) long, and then flake the fingerlings with a regular ring flaker. Round wood flakes generally produce high quality, strong pallets because the length and thickness can be precisely controlled. Round stock also tends to be somewhat flattened, which facilitates efficient blending.
The logs can then be peeled before flaking, which reduces the amount of undesirable fines during flaking and handling. Acceptable flakes can be produced by ring flaking of finger rings, and this technique can readily accommodate inferior forms of wood, thereby allowing the removal of certain types of residual and surplus wood. So it allows full utilization. Regardless of the particular technique used to produce the flakes, the size of the flakes, especially their length and thickness distribution, is of critical importance. Wood flakes are approx. 1.25
Average length of ~6 inches (3.18~15.24 cm),
and approximately 0.005 to approximately 0.075 inch (approximately 0.013 to approximately
It should have an average thickness of 0.191 cm). In any given batch, a portion of the flakes is
It can be shorter than 1.25 inches (3.18 cm) and a portion can be longer than 6 inches (15.24 cm) so long as the overall average length is within the ranges above. The same applies to thickness. The presence of a significant amount of flakes having lengths less than about 1.25 inches tends to pull the mat apart as the leg members are drawn from the mat during the molding process. This undesirable condition is particularly apparent at the corner joints between the leg members and the deck member, as will be described in detail below. The presence of some fines in the pine produces a smooth surface such that the majority of the wood flakes, preferably at least 75%, are longer than 1.125 inches (2.858 cm) and have an average length of at least 1.25 inches (2.858 cm). 3.18 cm) may be desirable for some applications. If the substantial amount of flakes is longer than 6 inches (15.24 cm), intercalation or felting of the flakes tends to occur during handling prior to pine formation and complicates drawing of the leg members. There is. For example, such mutual intercalation may interfere with proper coating of the flakes with binder during the compounding process, resulting in improper bonding of the flakes during molding. The average length of the wood flakes is preferably about 2 to about 3 inches (about 5.08 to about 3 inches).
7.62cm). The actual amount of flakes is approximately 0.005 inch (approximately 0.013
Thicknesses smaller than cm) should be avoided as the amount of binder required to obtain a proper bond will be excessive. On the other hand, about 0.075
Flakes having a thickness greater than an inch (about 0.191 cm) are relatively rigid and tend to overlap each other at some slant when forming into mats.
Eventually, excessively high mold pressures are required to bring the flakes into the desired close contact with each other. Regarding flakes having thicknesses that fall within the above range, thinner flakes produce a smoother surface, while thicker flakes require less binder. These two factors are balanced against each other when choosing the best average thickness for any particular application. The average thickness of the flakes is preferably about 0.015 to about 0.25 inches (approximately
0.038 to about 0.635 cm), most preferably about 0.020 inch (about 0.051 cm). The width of the flakes is not very important. The flakes should be wide enough to ensure that they lie substantially flat when felted during mat formation. The average width should generally be no more than about 3 inches (about 7.62 cm) and less than the average length. For best results, the bulk of the flakes should be around 1/16 ~
It should be approximately 3 inches wide. The thickness of the flakes can be adjusted primarily by a blade placed on the flaker. The length and width of the flakes are highly adjustable by the flaking operation as well. For example, when flakes are being produced by ring flaking finger rings, the maximum length is generally set by the length of the finger rings. Other factors, such as the moisture content of the wood and the amount of bark on the wood, affect the amount of fines produced during flaking. Dry wood is more brittle and tends to produce greater amounts of fines. The skin is
During flaking and subsequent handling, it tends to be more easily broken down into fine particles than wood. Although the flake size is highly controllable during the flaking operation as mentioned above, some sort of classification is usually used to remove undesirable particles, both too small and too large. It is necessary to ensure that the average length, thickness and width of the flakes are within the desired range. When using round stock flaking, it is usually necessary to use both screens and air classification to properly remove both undersized and oversized particles; Can be properly sized by chisel. Flakes from raw wood can contain up to 90% moisture. The moisture content of this mat must be substantially low for molding, as discussed below. Also, wet flakes tend to stick together, complicating classification and handling prior to compounding. The flakes are therefore preferably dried in a conventional type of dryer, for example a tunnel dryer.
Prior to classification, it is dried to the desired moisture content for the compounding process. The flakes are usually dried to about 6% by weight or less, preferably about 2 to about 5% by weight, based on the dry weight of the flakes. If desired, the flakes may be dried to a moisture content of around 10-25% by weight before classification.
It can then be dried to the desired moisture content for post-classification formulation. This two-step drying can reduce the total energy requirement for drying flakes made from green wood. This is because the drying of particles that must be removed during classification is no longer necessary in the second stage of drying. A known amount of dried, classified flakes is introduced into a conventional compounder, such as a paddle batch compounder, where a predetermined amount of resinous particle binder, wax and other additives are added as required. Additives are added while tumbling or stirring the flakes in the compounder. Suitable binders include those used in the manufacture of particleboard and similar pressed textile products, and are thus referred to herein as "resinous particleboard binders." Representative examples of suitable conjugates are: thermosetting resins, e.g.
Formaldehyde, resorcinol-formaldehyde, melamine-formaldehyde, urea-formaldehyde, urea-furfural and condensed furfuryl alcohol resins, and organic polyisocyanates alone or in combination with urea-formaldehyde or melamine-formaldehyde resins. Particularly suitable polyisocyanates are those containing at least two active isocyanate groups per molecule, such as: diphenylmethane diisocyanate, m-phenylene diisocyanate,
p-phenylene diisocyanate, chlorophenylene diisocyanate, toluene diisocyanate, toluene diisocyanate, triphenylmethene triisocyanate, diphenyl ether-2,4,4'-triisocyanate and polyphenyl polyisocyanates, especially diphenylmethane-4,4' -Diisocyanates. The particular type of binder used will depend primarily on the intended use of the pallet. For example, urea-
Pallets using formaldehyde resins have sufficient moisture resistance for many applications where exposure to moisture is minimal, but they generally cannot withstand extended outdoor exposure and have very little reusability. limited. Phenol-formaldehyde and melamine-formaldehyde resins provide excellent moisture resistance but require substantially longer cure times. Polyisocyanates, even in small amounts, provide greater strength and moisture resistance than urea-formaldehyde or phenol-formaldehyde resins, and the resulting pallets can be reused for an extended number of cycles.
Polyisocyanates cure in about the same time as urea-formaldehyde resins. However, polyisocyanates are expensive and tend to stick to metal parts, requiring the use of mold release agents. These factors are balanced against each other when choosing a particular binding agent for use. A binder system containing both a urea-formaldehyde resin and a polyisocyanate in a solids weight ratio of about 4:1 to about 1:1 is less expensive than the polyisocyanate alone, but is less expensive than the urea-formaldehyde or phenol-formaldehyde resin. It provides superior strength properties and moisture resistance than binders obtained alone, and the pallets are reusable, which is beneficial for many applications. The amount of binder added to the flakes during the compounding process is
It depends primarily on the particular binder used, flake size, moisture content and type, and the desired properties of the pallet. Generally, the amount of binder added to the flakes is from about 2% to about 15%, preferably from about 4% to about 10% by weight solids, based on the dry weight of the flakes. When using polyisocyanates alone or in combination with urea-formaldehyde resins, the amounts can always be towards the lower end of these ranges. The binder can be mixed with the flakes in dry or liquid form. For maximum coverage of the flakes, the binder is preferably applied by spraying drops of liquid binder onto the flakes as they are being tumbled or agitated in a blender. When polyisocyanates are used, a conventional mold release agent is preferably applied to the surface of the die or formed mat before pressing. To improve the water resistance of the pallets, preferably a conventional liquid wax emulsion is also sprayed onto the flakes during the compounding process. The amount of wax to add is
Generally, from about 0.5% to about 2% by weight solids based on drying properties of the flakes. Other additives may also be added to the flakes during the compounding process, such as colorants, flame retardants, insecticides, fungicides, etc. Binders, waxes and other additives can be added separately in any order or in combined form. The wet mixture or composition of binder, wax and flakes from the compounding process is formed into a loosely felted single or multilayer mat which is compressed into a pallet. The moisture content of the flakes should be adjusted within certain limits to provide adequate coverage by the blender during the compounding process and to increase binder hardening and flake deformation during molding. The presence of moisture in the flakes promotes the blending of the flakes into intimate contact with each other and forming leg members, and enhances uniform heat transfer throughout the mat during the forming process, thereby providing a uniform Ensure hardening. However, excessive amounts of water tend to decompose some binders, especially urea-formaldehyde resins, and generate water vapor that can cause blistering. On the other hand, if the flakes are too dry, they will contain an excessive amount of binder, leaving an insufficient amount of binder on the surface to obtain good bonding, and the surface will tend to harden. Yes, this prevents the desired chemical reaction between the binder and the cellulose in the wood. The latter condition is
This is particularly the case with polyisocyanate binders. Generally, the moisture content of the composition after completion of compounding will be from about 5 to about 25 percent by weight, including the original moisture of the flakes and any moisture added during compounding with binders, waxes, and other additives. %, preferably from about 8 to about 12% by weight. Generally, high moisture content within these ranges can be used for polyisocyanate binders. This is because polyisocyanate binders do not produce binding products upon reaction with cellulose in wood. The composition is formed into a rectangular, generally flat, loosely felted mat, preferably a multilayer mat, corresponding to the outside dimensions of the pallet. Mats can be formed using conventional dispensing systems similar to those disclosed in US Pat. Nos. 3,391,223 and 3,824,058. Generally, such dispensing systems include a plate-like carriage supported on an endless belt or conveyor and one or more (e.g., three) plate-like carriages spaced along the belt in the direction of travel for receiving the composition. (1) hoppers included. When forming a multilayer mat in accordance with a preferred embodiment, a plurality of hoppers are typically used, each hopper having a dispensing head extending across the width of the carriage that distributes the composition as the carriage moves beneath them. Depositing separate layers of something in succession. In order to produce a pallet with the desired strength properties, the mat should have a substantially uniform thickness, and the flakes should lie substantially in a horizontal plane parallel to the surface of the carriage, and They should be randomly oriented with respect to each other in that plane. Mat thickness uniformity can be controlled by depositing two or more layers of the composition on the carriage and metering the flow of the composition from the forming head. The desired irregular orientation of the flakes is such that the forming head is spaced above the carriage so that the flakes are about 1 to about 3 inches (about 2.54 to about 3 inches) into the carriage.
7.62 cm). When flat flakes fall from that height, they tend to fall downward in a spiral and generally land flat in an irregular pattern. Wider flakes within the aforementioned range enhance this effect. A scraper or similar device spaced above the carriage can be used to ensure uniform thickness or depth of the mat. However, such measures usually tend to align the top layer of flakes, ie, eliminate desired irregularities. Therefore, the thickness of the mat is preferably controlled by precisely metering the flow of composition from the forming bed. The thickness of the pine used depends on the size and shape of the wood flakes, the specific technique for forming the pine, the desired thickness and density of the decking and leg members of the pallet, the shape of the pallet (particularly the size and size of the leg members). shape) and the molding pressure used. For example, if the pallet is
0.5 inch (1.27 cm) deck member and 45 lb/
When using a cubic foot (0.72 g/cm ³ ) density, pine is typically about 3 inches (about 7.62 cm) when using round wood flakes and when using flakes produced by finger ring ring flaking. It will have a thickness of about 4 inches. Of all these variables, the final density of the pallet is the primary factor in determining the thickness of the pine. Referring to FIG. 4, mat 30 is compressed in a heated press or mold 32. This mold 3
2 includes a movable M die 34 and a stationary F die 36, which together define a mold chamber having the shape of a pallet. The F die 36 includes a plurality of cavities 40 (one shown), each cavity defining the exterior of the leg member 16, and the M die 34 includes a plurality of corresponding projections 42 (one shown). each protrusion defines an interior portion of the leg member 16. Mat 30 is removed from the forming carriage and deposited onto F die 36 as illustrated. When the M die 34 is closed, a portion of the mat 30 is drawn or drawn down into the cavity 40 of the F die to form the leg member 16. This is in contrast to the flow of material into the mold when using plastic materials and finely divided fibrous molding compositions. In this way, the leg member 16 and the deck member 1
The corner joints between 2 and 2 are particularly susceptible to structural weakening resulting from the tendency of the flakes to thin out and separate during the forming operation. The method of the present invention uses wood flakes having dimensions mostly within the ranges mentioned above, and uses pine
This tendency is minimized by forming a layer of wood flakes that is substantially flat and irregularly oriented. Instead of pulling the corner joint apart, a number of the flakes bend or deform somewhat around the corner, thereby providing a joint with substantial structural integrity. Because of this drawing or drawing effect on the mat during molding, there are some practical limitations on the shape of the pallet. Referring to FIG. 2, the slope of sidewalls 22 and 24 with respect to the main horizontal plane of deck member 16, indicated by angle A, should not exceed about 78 degrees. If a relatively tight fit between the bottom of deck member 12 and leg member 16 is desired, the outer radius, designated R ₁ , should be substantially larger than the inner radius, designated R ₂ . Large leg members (e.g. 7 inches x 9 inches (17.78 cm x 22.86 cm))
Generally, when the sidewalls are of the same slope, the smaller leg members [e.g., 5 inches (12.7 cm) diameter]
It is easier to mold than. Generally, the slope and depth are smaller for smaller leg members. The side walls 22 and 24 of the leg members are typically 70 to 110 mm thicker than the deck member.
%, preferably about 80-85%.
The thickness of the bottom wall is approximately 60 to 100% of the thickness of the deck member.
can be. Leg members shall not be closer together than approximately 6 inches. Even at this distance, additional amounts of flake may be required to compensate for the amount of flake drawn or drawn down into the F-die cavity during the forming operation, especially when forming deeper or longer leg members. be. For example, as shown in FIG. 4, a pine is formed outside the mold and placed between the M and F dies, and has nine leg members. ), leg members having a depth of up to about 1.75 inches (indicated by dimension D in FIG. 2) can be conveniently drawn from such mats. Figures 5-7 illustrate another technique for depositing flakes in a mold so that longer or deeper leg members can be drawn. In the technique shown in FIG. 5, the cavity 40 of the F-die 36 is first substantially filled with a composition 44 and then formed outside the mold to a substantially uniform thickness, similar to the mat 30 in FIG. After the loosely felted mat 46 is deposited onto the F die 36 over the filled cavity, the mold is closed. In the technique illustrated in FIG. 6, a loosely felted mat 48 of substantially uniform thickness is formed outside the mold, similar to mat 30 in FIG. A mound 50 of additional composition is deposited on top of the mat 48 at a location corresponding to the location of the F die cavity 40, and the mat 48 is then placed in the mold. The technique illustrated in FIGS. 5 and 6 has been successfully used to form pallets with leg members up to 5 inches (12.7 cm) or more deep and sidewall slopes of 56° to 77°. Ta. In the technique illustrated in FIG. 7, mat 52 is loosely felted directly onto F-die 36 by passing F-die 36 under a forming head (not shown). Alternatively, the mat can be deposited on a remote caul plate or pan that matches the F-die, which is subsequently placed over the F-die. Additional compositions required for deep drawing are:
This is provided by the tendency of the F-die cavity 40 or caul plate to absorb excess composition during the felting operation. The temperature, pressure and time of molding will vary widely depending on the thickness and desired density of the pallet, the size and type of wood flakes, the moisture content of the flakes, and the type of binder used. The temperature used is
Within a reasonable amount of time, at least enough to harden the binder and drive water out of the pine without charring the wood. Generally, molding temperatures ranging from ambient temperature to about 450°C (about 232°C) can be used. Temperatures higher than approximately 450°C (approximately 232°C) may char the wood. When using a binder system containing a urea-formaldehyde resin and a polyisocyanate, from about 250 to about 375〓 (from about 121 to about 191
A molding temperature of 300°C is preferred, whereas the phenol-formaldehyde resin binder has a molding temperature of about 300°C.
A molding temperature of ~425°C (149°C to about 218°C) is preferred. The molding pressure used is sufficient to press the wood flakes into close contact with each other without breaking them, to the point where the lignin begins to leach out, breaking the fibers and degrading the integrity of the structure. Should. Molding pressure applied to the net die area typically ranges from about 300 to about 700 psi (about 21.1 to about 49.2
kg/cm ³ ). The time of the molding or pressing cycle is sufficient to at least partially cure the binder to the point that the pallet has suitable structural integrity for handling. Press cycles typically range from about 2 to
It takes about 10 minutes. However, shorter or longer times can be used when using pressure-cure binders or when more complete curing of some thermoset binders is desired. After the pallet is removed from the mold, the edges are trimmed to the desired final dimensions, eg, 40 inches by 48 inches (101.6 cm by 121.9 cm). The forming apparatus may include means for providing built-in trimming during pressing. A typical pallet will contain about 9% resin, about 1% wax and about 92% wood by weight when using a thermosetting resin type binder. The resin content is typically about 5% by weight when a polyisocyanate resin is used and about 7% by weight when the binder is a combination of urea-formaldehyde resin and polyisocyanate. Those skilled in the art can, using the foregoing description, have no trouble
It is believed that the present invention can be utilized to its fullest extent.
This will be further explained by the following examples. These examples should not be considered as limiting the invention. EXAMPLE Poplar round wood flakes [average length 1.75 inches (4.45 cm), average thickness 0.21 inches (0.53 cm)] were made in accordance with the present invention using 9% by weight urea-formaldehyde resin and /% by weight wax. Sample pallets were tested for various strengths. The sample pallets had an average density of 39 pounds per cubic foot (0.63 Kg/cm ³ ). 300~350psi (21.1
~24.6Kg/ ^cm3 ) pressure, 300~325〓(149~163
℃) and a pressing time of 4.5 to 7 minutes were used for molding. Leg crush test is Tinius-Olson)
Olson) test machine, 16 leg sections in dry condition, and 16 soaked for 24 hours and then dried to constant weight at 15% relative humidity and 70°C (21°C).
It was carried out using the leg part of. The average crush strength for maximum load was 3.548 lbs (1.611 Kg) for the first group and 2.727 for the second group.
It weighed 1.238 kg (1.238 kg). Based on these test results, the nine-legged palette is theoretically
Can support up to 24.543 lbs (11.143 Kg) after soaking and redrying. The strength of the deck is 3 inches x 14 inches (7.62 cm x 35.56 cm) cut from the deck of the sample pallet.
Determined by testing samples of The average crush coefficient is 2.435 pounds per square inch (171.2
Kg/cm ³ ). When other samples were soaked for 48 hours and tested when moistened, the average crush modulus was 1000 pounds per square inch (70.3 Kg/cm ³ ). EXAMPLE Pallets with legs of different sizes and shapes were molded from various flakes and binders.
Leg sections from these pallets were tested for crush strength. The legs of these pallets were conditioned at 50% relative humidity and 70°C (21°C) and were subjected to a compressive load perpendicular to the pallet deck surface at a rate of 0.10 in/min (0.254 cm/min).
A maximum bend of 0.5 inch (1.27 cm) was applied at a loading rate of 1 minute). The results from these tests are summarized in the table.

[Table] From these test results, all leg parts are
ASTM Static Load Capacity Test minimum requirements, i.e. the center leg of a 2000 lb (908 Kg) capacity pallet supports 15% of 9750 lb (4426 Kg) or 1462 lb (663.7 Kg) You can see that it far exceeds the requirements that it must be done. From the above description, those skilled in the art can easily ascertain the essential features of the present invention, and can make various changes and modifications to adapt the invention to various uses and conditions without departing from the spirit and scope of the invention. can be adapted.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a pallet having various features of the present invention. Figure 2 shows line 2-2 in Figure 1.
FIG. FIG. 3 is a schematic flow diagram illustrating the various steps of a preferred method of forming pellets of the present invention from residual and surplus wood. Figures 4-7 are simplified schematic side views of a mold or press illustrating various techniques for depositing matts of wood flakes on the F-die before closing the mold. 10...Pallet, 12...Deck member, 14
... Upper surface, 16 ... Hollow leg member, 18 ... Bottom wall, 20 ... Bottom surface, 22 ... Side wall, 24 ... Side wall, 30 ... Mat, 32 ... Press or mold, 34 ... ...Movable M die, 36...Stationary F die, 40...Cavity, 42...Protrusion, 44...
...Composition, 46...Matsuto, 48...Matsuto, 5
0...Mound, 52...Matsuto.

Claims (1)

[Scope of Claims] 1. A rectangular deck member having an upper surface horizontal to the main plane; and a plurality of spaced parallel rows of hollow leg members projecting integrally from the deck member, each of which The leg members in the row are also laterally aligned with the leg members in adjacent rows, and each leg member is spaced apart from the deck member and has a pointed end of a forklift below the deck member. an opposed pair of side walls connecting the bottom wall to the deck member and sloping outwardly from the bottom wall toward the deck member; The deck members and leg members are formed as a unitary unit from a layered mixture of a resinous particle board binder and flake-like wood particles having an average length of 1.25 to 6 inches (3.18 to 6 inches).
15.24 cm), an average thickness of 0.005 to 0.075 inches (0.013 to 0.191 cm), and an average width of no more than 3 inches (7.62 cm) and less than an average length, each layer of the wood particles having a major plane. 1. A pallet characterized in that at least said decking member is formed substantially substantially flat in a plane generally parallel to said pallet, said wood particles therein being irregularly oriented. 2. The pallet of claim 1, wherein the side walls extend at an angle of less than 78 degrees with respect to the major plane of the deck member. 3. The pallet according to claim 1, wherein the average thickness of the side walls is 70 to 110% of the average thickness of the deck member. 4 The average thickness of the wood particles is 0.015 to 0.025 inches (0.038 to 0.064 cm), and the average length is 2
3. The pallet of claim 1, wherein the pallet is 3 inches (5.08-7.62 cm). 5. The pallet of claim 4, wherein the wood particles have an average width of 1/16 to 3 inches (0.159 to 7.62 cm). 6 The molded deck member and leg member are 2-
A pallet according to claim 1 containing 15% by weight of said binder. 7. The pallet of claim 6, wherein said binder comprises an organic polyisocyanate having at least two active isocyanate groups per molecule. 8 a rectangular decking member having an upper surface horizontal to a major plane; and a plurality of spaced parallel rows of hollow leg members projecting integrally from the decking member, the legs in each row The members are also laterally aligned with the leg members in adjacent rows, each leg member being spaced apart from the deck member with sufficient spacing to accommodate the sharp end of a forklift beneath the deck member. a bottom wall; an opposed pair of side walls connect the bottom wall to the deck member and slope outwardly from the bottom wall toward the deck member; Molded as a unitary unit from a layered mixture of a resinous particle board binder and flake-like wood particles having an average length of 1.25 to 6 inches (3.18 to 6 inches)
15.24 cm), an average thickness of 0.005 to 0.075 inches (0.013 to 0.191 cm), and an average width of no more than 3 inches (7.62 cm) and less than an average length, each layer of the wood particles having a major plane. 1. A method of manufacturing a pallet, characterized in that at least said deck member lies substantially flat in a plane generally parallel to said deck member, said wood particles therein being irregularly oriented. , the deck member and the foot member loosely transfer the mixture from the wood particles onto one portion of an open mold comprising two separable portions defining a mold chamber having the desired shape of the pallet. The felted layered pine is deposited, the mold is closed, and sufficient heat and pressure is applied to the pine to substantially compress it to the desired shape and size of the pallet and compress the wood particles. A method of manufacturing pallets formed by joining them together.