JP2008502554A - Pallet and its manufacturing method - Google Patents

Abstract

[0132]
A pallet and a manufacturing method thereof are provided. The pallet includes a pallet body, a skid that reinforces the pallet body, and means for connecting the pallet body and the skid. The pallet body and skid are molded from a moldable composition comprising about 40 to 60% by weight fiber mixture and about 15 to 45% by weight adhesive. The pallet manufacturing process begins with the preparation of this moldable composition. The mold cavity is loaded with the moldable composition to about 90% of its volume, after which a packing pressure of about 435 to 870 psi is applied to the moldable composition. A predetermined gap of about 0.1 to 0.5 mm is maintained between the first mold part that defines the mold cavity and the second mold part. When the moldable composition is substantially cured, the molded product is removed from the mold cavity.

Description

  The present invention relates generally to pallets for handling, storing, or moving materials and luggage.

  Pallets are widely used for collecting, storing, stacking, handling and transporting items as unit packages, and are made primarily of wood, metal or plastic.

  The most commonly used is a wooden pallet. In recent years, however, wooden pallets have become environmentalists due to the deforestation and environmental problems that arise as a result of interstate and continental imports and exports of landfill waste and piercing wood. And has been the focus of attention by various government agencies. As a result, in many countries, the use of wooden solid packaging materials imposes some restrictions, such as ISPM 15 (International Standard 15 for phytosanitary measures) by the World Health Organization (WHO).

  Current alternatives to wooden pallets are plastic and metal pallets. However, since plastic and metal pallets are more costly than wooden ones, the use of such pallets is kept to a minimum. Besides expensive costs, plastic and metal pallets have disposal problems because plastic and metal are not biodegradable and therefore cannot be disposed of efficiently. In addition, the use of recycled plastic in the manufacture of plastic pallets is harmful to the environment, as the decomposition of the plastic releases toxic fumes into the atmosphere and contaminates the soil and water quality.

  In view of the above, it is desirable to have a biodegradable pallet made from an immediately renewable resource and a method for making it.

  The present invention meets these needs by providing a biodegradable pallet and a method for its manufacture. It should be appreciated that the present invention can be implemented in a number of ways including a process, apparatus, system, device or method. Several inventive embodiments of the present invention will be described below.

  One embodiment of the present invention provides a biodegradable pallet comprising a pallet body, a skid that reinforces the pallet body, and means for connecting the pallet body and the skid. The pallet body and skid are molded from a moldable composition comprising about 40-60% by weight fiber mixture and about 15-45% by weight adhesive.

  The moisture content of the moldable composition is preferably less than about 20%. More preferably, the moisture content of the moldable composition is about 4-15%. Most preferably, the moisture content of the fiber mixture is less than about 15%.

  Preferably, the moldable composition further comprises up to about 40% by weight of additives. The additive may be one or more of the group consisting of a curing agent, a glidant and a release agent.

  Preferably, the fiber mixture includes a plurality of fibers, each of the plurality of fibers being up to about 50 mm in length. Each of the plurality of fibers is preferably up to about 2 mm thick and the length to thickness ratio is about 2: 1 to 25: 1.

  Preferably, the fiber mixture comprises about 5-30% by weight of oil palm fibers. The fiber mixture may comprise one of the group consisting of oil palm fiber, beer malt, sugarcane pulp, plasticizer, reinforcing agent and impact modifier.

  Preferably, the adhesive is a thermosetting resin. More preferably, the adhesive is an amino resin. More preferably, the adhesive is melamine. Most preferably, the adhesive is one of the group consisting of melamine formaldehyde and melamine urea formaldehyde.

  In a preferred embodiment, the pallet body includes a load bearing member having legs. Preferably, the load bearing member has a thickness of about 3-5 mm which is substantially constant. Preferably, the load bearing member includes a plurality of ribs, each rib having a tapered groove wall and a draft of about 6-12 degrees (°) from a normal to the surface of the load bearing member 18. With an open groove designed to be

  The legs are preferably formed as concave depressions in the load bearing member. Preferably, the legs are designed to taper towards the base and have a draft of about 11-12 ° from the normal to the surface of the load bearing member 18 and a minimum vertical height of about 95 mm.

  In a preferred embodiment, a blind hole is preferably provided in the base. The blind hole is preferably designed to have a draft of less than about 0.5 ° from the normal to the surface of the load bearing member 18.

  Preferably, a first fillet is formed at a portion where the leg and the load bearing member intersect. Preferably, fins are provided along the outer periphery of the load bearing member.

  In a preferred embodiment, the skid comprises a framework formed from a plurality of tethers. Preferably, a second fillet is formed at a joint where the plurality of connecting materials are joined. Preferably, the skid includes a protruding plug corresponding to a blind hole in the base of the leg. The blind hole connects to this protruding plug. The outer dimension of the protruding plug is preferably about 0.05 mm to 0.1 mm larger than the outer dimension of the blind hole, so that when a force is applied to connect the blind hole and the protruding plug, the skid is caused by an interference fit. Fixed to the pallet body. Preferably, the protruding plug is designed to have a draft of less than about 0.5 ° from the normal to the surface of the skid 14.

  In certain preferred embodiments, the pallet is designed to cover at least about 60% of the upper platform and at least about 35% of the lower platform.

  Another embodiment of the present invention provides a method of producing a high strength molded product. The method begins by providing a moldable composition. The moldable composition comprises about 40-60% by weight fiber mixture and about 15-45% by weight adhesive. The mold cavity is loaded with the moldable composition to about 90% of its volume, after which a packing pressure of about 435-870 psi is applied to the moldable composition. A predetermined gap of about 0.1 to 0.5 mm is maintained between the first mold part defining the mold cavity and the second mold part. When the moldable composition is substantially cured, the molded product is removed from the mold cavity. The pressure is preferably applied for about 20-60 seconds.

  Preferably, the first mold part and the second mold part are maintained at a temperature of about 110-180 ° C. More preferably, the temperature of the first mold part is maintained about 20 ° C. above the temperature of the second mold part.

  The predetermined gap between the first mold part and the second mold part is preferably increased to about 10 mm when the moldable composition is about 90% cured.

  The molded product is preferably compressed to the desired thickness, and the surface of the molded product preferably has a predetermined gap between the first mold part and the second mold part of about 15-60. Reduced by about 0.05 to 0.3 mm per second.

  Preferably, the moldable composition comprises up to about 40% by weight of additives. The additive may be one of the group consisting of a curing agent, a glidant and a release agent.

  Preferably, the water content of the moldable composition is less than about 20%. More preferably, the moisture content of the moldable composition is about 4-15%. Preferably, the moisture content of the fiber mixture is less than about 15%.

  The fiber mixture preferably includes a plurality of fibers, each of the plurality of fibers having a length of up to about 50 mm and a thickness of up to about 2 mm. Preferably, the length to thickness ratio of each of the plurality of fibers is about 2: 1 to 25: 1. The fiber mixture preferably comprises about 5 to 30% by weight of oil palm fibers. Preferably, the fiber mixture comprises one of the group consisting of oil palm fibers, beer malt, sugarcane pulp, plasticizers, reinforcing agents and impact modifiers.

  The adhesive is preferably a thermosetting resin. More preferably, the adhesive is an amino resin.

  Preferably, the adhesive comprises melamine. The adhesive may be one of the group consisting of melamine formaldehyde and melamine / urea / formaldehyde.

  The moldable composition is preferably prepared by individually weighing the components of the moldable composition and then mixing the components of the moldable composition in a mixer. Preferably, each liquid component of the moldable composition is mixed in a second mixer to form a liquid mixture, which is preferably sprayed into the mixer. The mixer is preferably operated at a rotor speed of about 29 rpm.

  In yet another embodiment of the present invention, a method of manufacturing a molded product is provided. The method begins by loading the mold cavity with a moldable composition comprising about 40-60% by weight fiber mixture and about 15-45% by weight adhesive. The mold cavity is loaded to about 90% of its capacity. The mold then operates to apply a packing pressure in the range of 435-870 psi to the moldable composition therein. An outlet is provided for water vapor, which is responsive to the pressure in the moldable composition and which extends the water vapor content to produce a molded product having a predetermined density and strength. It is set to control the pressure in the composition to a predetermined value. When the moldable composition is substantially cured, the molded product is removed from the mold cavity.

  Preferably, the outlet is provided by maintaining a predetermined gap between individual parts of the mold adjacent to the moldable composition. The outlet may be temporarily blocked for a predetermined period of time with a moldable composition to temporarily prevent the release of water vapor.

  The water vapor content is preferably controlled to produce vapor bubbles in the moldable composition and thereby produce a porous molded product of a predetermined density.

  Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

  The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. For ease of explanation, like numbers refer to like structural elements.

  A biodegradable pallet and a manufacturing method thereof are provided. In the following description, certain specific details are set forth in order to provide a thorough understanding of the present invention. However, one skilled in the art will understand that the invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.

  FIG. 1 is a perspective view showing a biodegradable pallet 10 according to an embodiment of the present invention. The pallet 10 includes a pallet main body 12, and the pallet main body 12 is reinforced by being coupled to a detachable skid 14 by a connecting means 16. The skid 14 enhances the rigidity and stability of the pallet 10 and allows the pallet 10 to be specified for material handling applications using various types of transport systems such as forklifts, electric pallet jacks and manual pallet jacks. Adapt.

  The pallet body 12 is substantially provided with legs 20 depending on the center S of the load bearing member 18, the length L and the width W, and the corners and midpoints in order to make the pallet 10 stable. A flat load bearing member 18 is provided. However, one of ordinary skill in the art will recognize that the depending leg 20 may be located in only some of these locations or elsewhere on the load bearing member 18. The load bearing member 18 may have a wall thickness that is substantially constant between about 3 and 5 millimeters (mm).

  Each leg 20 is formed as a concave depression in the load bearing member 18 to allow nested overlap of pallets, thereby reducing space requirements and facilitating use as a cube for transportation and storage. . Furthermore, the hollow leg 20 contributes to the reduction of the weight and material cost of the pallet 10. In some alternative embodiments, the legs 20 may have a solid core.

  Referring to FIG. 2, which is a bottom view of the pallet body 12 according to one embodiment of the present invention, each leg 20 tapers inward toward the base 22. The taper of the legs 20 facilitates removal of the pallet 10 from the mold and separation of the nested pallets. A blind hole 24 is provided in the base portion 22 of the leg 20.

  The legs 20 are designed to have a minimum vertical height of about 95 mm to suit various types of lifting devices such as forklifts, electric pallet jacks and manual pallet jacks.

  A first fillet 26 is formed where the leg 20 contacts the load bearing member 18. The first fillet 26 reduces the tendency for cracks to form at the joint between the leg 20 and the load bearing member 18 and reinforces the pallet body 12.

  Referring again to FIG. 1, a plurality of ribs 28 are provided on the load bearing member 18 to reinforce the pallet body 12. Each rib 28 includes an open groove 30 that allows for nesting stacking of pallets to reduce space requirements and facilitate use as a cube in transportation and storage. The hollow ribs 28 contribute to reducing the weight of the pallet 10 and reducing the material and transportation cost of the pallet 10. Each open groove 30 has a tapered groove wall that facilitates removal of the pallet 10 from the mold and separation of the nested pallets. In certain alternative embodiments, the ribs 28 may have a solid core. It will be appreciated that the arrangement of the plurality of ribs 28 shown in this embodiment is merely exemplary, and that there are several possibilities for the arrangement of the plurality of ribs 28.

  The ribs 28 are about 6 to 12 from the normal to the surface of the load bearing member 18 to facilitate protrusion or removal of the pallet body 12 or skid 14 from the mold and also to assist in separating the nested pallets. Designed to have a taper or draft of degrees (°).

  Along the outer periphery of the load bearing member 18 are provided fins 32 that facilitate the extraction of the pallet body 12 from the mold and the handling of the pallet 10. The fins 32 also serve to reinforce the outer periphery but prevent cracks or foil formation when the pallet 10 is dropped.

  In essence, the fins 32 and the plurality of ribs 28 distribute the tensile and compressive strength to the pallet body 12 so that the pallet 10 has minimal deflection during loading, stacking and warehousing, and any impact during transport. Makes it possible to withstand.

  FIG. 3 is a perspective view showing a skid 14 according to an embodiment of the present invention. The skid 14 includes a frame formed from a plurality of connecting members 34. A second fillet 36 is formed at the joint where at least two binders 34 contact. The second fillet 36 reduces the tendency for cracks to be formed at the joint where the joining members 34 are joined together, and reinforces the skid 14.

  The skid 14 includes a plurality of protruding plugs 38. Each protruding plug 38 corresponds to the blind hole 24 in the base portion 22 of the leg 20 shown in FIG.

  The pallet 10 covers at least about 60% of the upper carrier to fully support the objects loaded on the pallet 10 and covers at least about 35% of the lower carrier to ensure the stability of the pallet 10. Designed as such. The minimum anti-slip requirements are met with at least about 60% upper carrier cover and at least about 35% lower carrier cover. The upper carrier cover is defined as the surface area of the load bearing member 18 expressed as a percentage of the total surface area of the pallet 10 and is calculated by multiplying the length L of the pallet 10 by the width W. The cover of the lower carrier is defined as the total surface area of the base 22 on the legs 20 or the surface area of the skid 14 depending on whether the skid 14 is attached to the pallet body 12, as a percentage of the total surface area of the pallet 10. expressed.

  FIG. 4 is a sectional view showing the connecting means 16 according to an embodiment of the present invention. The connecting means 16 connects the blind hole 24 in the base 22 of the leg 20 to the protruding plug 38. The outer dimension of the protruding plug 38 is blind in order to achieve an interference fit, i.e., one part being larger than the other, so that when fitted, the two tolerance fitting parts always interfere with each other. About 0.05 to 0.1 mm larger than that of the hole 24. The interference fit fixes the skid 14 to the pallet body 12 when a force for connecting the skid 14 and the pallet body 12 is applied.

The legs 20, blind holes 24 and protruding plugs 38 each facilitate loading or removal of the pallet body 12 or skid 14 from the mold and assist in the separation of the nested pallets and load bearing members 18. or from each of about 11 from vertical 12 ° taper or draft angle D _legs with respect to the surface of the skid 14, _projecting tapered or draft D of less than tapered or draft D _{blind hole} of less than about 0.5 ° and about 0.5 ° Designed to have _{a plug} .

  The pallets may be manufactured by a thermoforming process such as that described more fully in the co-pending patent application entitled “Method of Manufacturing High Strength Molded Products” which is included in this disclosure by reference. A molded product consisting of either a pallet body or a skid may be composed of a moldable composition comprising about 40 to 60 weight percent (wt%) fiber mixture and about 15 to 45 wt% adhesive. . The moldable composition may include up to about 40% by weight of additives.

  The moisture content of the moldable composition is preferably less than about 20%, more preferably about 4 to 15%. Higher moisture content reduces the concentration of adhesive in the moldable composition. Thus, longer processing times are required to cure moldable compositions having higher moisture content.

  Further, keeping the moisture content of the moldable composition below about 20% eliminates the need for further processing after curing to remove moisture from the molded product to prevent fungal growth. By minimizing the number of processes / steps, molded products can be produced at lower costs and shorter production cycle times.

  Moisture is inherently present in the fiber mixture and may also be present in adhesives and additives, so no addition of water is necessary. The moisture content of the fiber mixture is preferably less than about 15%. The water content of the moldable composition may rather be reduced by adding about 10 to 20% by weight of a co-solvent, such as an alcohol, which has a lower boiling point than water.

  The fiber mixture may include wood chips, used furniture, used wood pallets and sawdust from building construction and / or agricultural and horticultural waste such as leaves, stems and branches. Fibers from wood chips and agricultural and horticultural wastes are readily available at low cost, giving molded products excellent sound absorption and thermal insulation properties. Furthermore, such fibers also give the molded product firmness and resistance to deformation when stressed.

  The fibers are preferably up to about 50 mm in length, up to about 2 mm in thickness, and have a length to thickness ratio of about 2: 1 to 25: 1. Since the molded product draws its strength from the fibers rather than the bond provided by the adhesive, it is preferred to use longer fibers even though the longer fibers provide less surface area for bonding. Thus, lesser adhesive is required when longer fibers are used in the moldable composition.

  The fiber mixture may contain from about 5 to 30% by weight of oil palm fibers to increase the elasticity and ductility of the molded product, thereby reducing the brittleness of the molded product. However, since oil palm fibers are generally small in size, typically having a length of up to about 50 mm and a thickness of about 0.3 to 1 mm, molding with increased oil palm fiber content The strength of the product may decrease. Accordingly, the composition of the oil palm fibers in the fiber mixture may be varied according to the desired properties of the molded product.

  The addition of oil palm fibers is also preferred because the oil palm fibers have a low moisture content and contain lignin which is an excellent dispersant and acts as a binder under pressure.

  Oil palm fibers can be obtained from various parts of oil palm, such as trunks, leaves and fruits. These parts of oil palm are generally discarded parts. Therefore, the present invention provides a method for reducing waste and minimizing environmental pollution caused by oil palm incineration.

  In addition to its low cost, oil palm fibers are readily available in various sizes throughout the year.

  Oil palm fibers, such as beer malt and sugarcane pulp or chemicals such as plasticizers, reinforcing agents or impact modifiers, but not as suitable as oil palm fibers, but to increase the ductility and elasticity of the molded product Alternatives may be used.

The adhesive is preferably a thermosetting resin such as amino resin, epoxy resin, allyl resin, phenol resin, polyimide, silicone, polyester, polycyclic aromatic, or furan. More preferably, such resins can be well mixed with the fiber mixture to form a homogeneous mixture and ultimately produce a molded product that is resistant to heat, stress and chemicals, The adhesive is an amino resin. An amino resin is a thermosetting plastic material produced by reacting a compound having an amino group (—NH ₂ ) such as aniline, ethylene urea, guanamine, melamine, sulfonamide, thiourea and urea with formaldehyde.

  Suitably, the adhesive comprises melamine which imparts durability, heat resistance and water resistance to the molded product. Examples of adhesives containing melamine include melamine formaldehyde and melamine urea formaldehyde. Molded products manufactured using melamine, urea, and formaldehyde contain very little formaldehyde, which means that during the molding process, almost all the formaldehyde contained in the amino resin vaporizes, and the molded product has very little. This is because only a small amount of formaldehyde remains. Thus, the release of free formaldehyde from such molded products is insignificant and therefore not a health threat.

  The additive may be about 0.1 to 0.4% by weight of a curing agent such as ammonium chloride to accelerate the curing process of the adhesive, about 6 to 18 to reinforce the flow of the moldable composition. Containing about 0.2 to 0.9% by weight of a release agent, preferably soy lecithin, to aid in the removal of the molded product from the mold and a glidant such as weight% tapioca flour. Also good.

  Soy lecithin is a preferred release agent because it is a plant material, is renewable and biodegradable, does not contain toxic additives, and does not release toxic vapors during molding.

  Examples of moldable compositions that may be used in the manufacture of biodegradable pallets according to one embodiment of the invention are shown in Tables 1A, 1B and 1C.

図５は、本発明の一実施形態による生物分解性の成形可能な組成物の準備方法１００を示すフローチャートである。成形可能な組成物は、約４０から６０重量パーセント（重量％）の繊維混合物、約１５から４５重量％のメラミン・ユリア・ホルムアルデヒド、約０．１から０．４重量％の塩化アンモニウム、約６から１８重量％のタピオカ粉及び約０．２から０．９重量％の大豆レシチンを含む。

FIG. 5 is a flowchart illustrating a method 100 for preparing a biodegradable moldable composition according to one embodiment of the invention. The moldable composition comprises about 40 to 60 weight percent (wt%) fiber mixture, about 15 to 45 wt% melamine urea formaldehyde, about 0.1 to 0.4 wt% ammonium chloride, about 6 To 18% by weight tapioca flour and about 0.2 to 0.9% by weight soy lecithin.

  Method 100 begins by individually calibrating 102 each component of the biodegradable moldable composition using the weight gain principle or under vacuum.

  The components of the moldable composition are sequentially mixed 104 in a mixer for about 300 to 600 seconds to produce a substantially homogeneous and fully coated moldable composition.

  First, the fiber mixture is added to the mixer and mixed for about 10 seconds until tapioca flour is added. Tapioca flour and the fiber mixture are mixed for about 20 seconds. Thereafter, soy lecithin is added to the blender followed by melamine urea formaldehyde and then ammonium chloride and mixed for about another 300 seconds until a homogeneous moldable composition is produced.

  Liquid components such as melamine, urea, formaldehyde and ammonium chloride may be supplied to the mixer by pneumatic actuators or positive displacement screw feeders.

  In one preferred embodiment, the liquid component is sprayed 106 into the mixer to uniformly coat the fibers in the fiber mixture. The spray 106 of the liquid component into the mixer ensures a uniform distribution of the liquid component in the moldable composition. A pneumatically driven diaphragm pump or spray nozzle may be used to spray liquid component 106 into the mixer.

  Where the moldable composition includes two or more liquid components, the liquid components are mixed in a second mixer for about 200 seconds to form a liquid mixture prior to spraying 106 into the mixer. 108. The liquid component mixing 108 may occur simultaneously with the mixing 102 of the moldable composition components.

  Use mixers with dual rotor shafts and overlapping paddles to achieve homogeneity of the moldable composition and reduce the mixing time required to create a fluidization zone within the mixer. Is preferred. The creation of a fluidized zone reduces friction during mixing, thus minimizing heat generation and preventing premature curing of the moldable composition.

  The mixer may be operated at a rotor speed of about 10 to 200 revolutions per minute (rpm), but to minimize the generation of shear and heat acting on the moldable composition, it is about 29 rpm. It is preferable to operate at a rotor speed of. A high shear force causes the fibers to break down.

  The mixer may be equipped with a side door that is at least about 600 mm in height and at least about 600 mm in width so that the moldable composition can be efficiently dispensed with a minimum of residue. Large side door equipment also allows for quick inspection, high speed cleaning and good access.

  The moisture content of the moldable composition is preferably less than about 20%, more preferably about 4 to 15%. Higher moisture content causes the moldable composition to have insufficient viscosity to disperse the shear force from the mixer to coat the fibers uniformly.

  FIG. 6 is a flowchart illustrating a fiber mixture preparation method 150 according to an embodiment of the present invention. The method 150 begins when the first crusher receives a certain amount of wood, agricultural or horticultural waste that is sized in the crusher with each piece about 10 to 80 mm long and about 2 to 20 mm wide. 152 to be crushed into a plurality of waste pieces.

  The plurality of waste pieces may be sieved 154 with a first wire mesh having a plurality of openings with a size of about 80 mm in diameter and then conveyed to a second crusher 156 for pulverization into a plurality of fibers. The plurality of fibers, each about 5 to 50 mm in length and about 2 to 10 mm in width, may then be screened 158 with a second wire mesh having a plurality of openings about 50 mm in diameter.

  The plurality of fibers sorts metal pieces 160 using a metal detector. The metal piece is removed from the plurality of fibers before being sent to the third crusher along with the plurality of oil palm fibers. The resulting fiber mixture is made 162 by subsequent grinding into fibers having a length of up to about 50 mm and a thickness of up to about 2 mm. Following this, the fiber mixture may be screened 164 with a third wire mesh having a plurality of openings sized about 20 mm in diameter.

  In preparing a fiber mixture having the desired fiber dimensions, a single crusher can be used, but to minimize material handling and cutter alignment and to prevent crushing of the crusher For this reason, it is preferable to use three separate pulverizers. As an alternative to sieving, foreign materials, oversized particles and large fibers may be removed by hand.

  The fiber mixture is then dried 166 to a moisture content of less than about 15%. Upon drying, the fiber mixture may be spread on the concrete floor of the drying shelter for about 1 to 2 weeks. The fiber mixture may be dried using a rotary dryer with a spotlight, blower, ultraviolet (UV) radiation from the sun or a heating system. Sometimes the fiber mixture may be re-rolled to achieve a uniform dryness. The fiber mixture may be analyzed on its random sample prior to delivery or storage in a silo to determine if the desired fiber size, moisture content and composition has been achieved.

  The fiber mixture may be transported through a manufacturing plant by a screw conveyor. The fiber mixture may be conveyed from the screw conveyor to the storage silo using an aerodynamic conveyor.

  A press for producing a molded product from a moldable composition according to one embodiment of the present invention is shown in FIGS.

  FIG. 7 shows a press 200 for producing a molded product according to an embodiment of the present invention. The press 200 includes a frame 202 having a first platen 204 and a plunger 206 coupled to a second platen 208. A first mold part or female part 210 defining a mold cavity 211 is provided on the first platen 204 and a second mold part or male part 212 defining a mold plunger 213 is a second platen. Coupled to 208. The plunger 206 moves the mold plunger 213 in the direction of the mold cavity 211 or from the mold cavity 211. The second mold part 212 includes one or more cooperating with complementary elongated recesses 215 in the first mold part 210 to align the mold plunger 213 with the mold cavity 211 during operation of the plunger 206. Guide pins 214 may be provided.

  The press 200 may be a mechanical press, a pneumatic press, or a hydraulic press. However, the press 200 gives greater control flexibility and appropriately applies applied force, direction of pressure holding, speed, duration, and the like. The use of a hydraulic press is preferred in that it can be adjusted.

  In manufacturing a molded product, first the mold cavity 211 is loaded with biodegradable moldable composition 216 to about 90% of its capacity. The degree to which the mold cavity 211 is filled depends on the compression ratio of the molded product, that is, the ratio of the wet amount to the dry weight of the molded product. The wet weight of the molded product is the weight of the moldable composition used to manufacture the molded product, and the dry weight of the molded product is the weight after curing of the molded product. The compression ratio is preferably about 4: 1 to 14: 1. The shrinkage rate is preferably about 1% in the horizontal direction and about 1.5% in the vertical direction.

  The first mold part 210 and the second mold part 212 are maintained at a temperature of about 110 to 180 ° C. by a first heat transfer oil heating system 230 and a second heat transfer oil heating system 232, respectively. A thermal controller (not shown) is provided to condition the first mold part 210 and the second mold part 212. The moldable composition 216 compensates for heat loss when the mold cavity 211 is loaded, and the first mold part 210 and the second mold part 212 are used for the first mold part 210 and the second mold part 212. To prevent clogging due to thermal expansion, the first mold part 210 is preferably maintained at a temperature about 20 ° C. above the temperature of the second mold part 212.

  The mold plunger 213 is moved in the direction of the mold cavity 211 at a rate of about 80 millimeters per second (mm / sec) until just before the mold plunger 213 contacts the moldable composition 216. This speed is then reduced to between about 0.5 and 3 mm / sec, abrupt for moldable composition 216, which is undesirable because it induces stress in mold plunger 213 and moldable composition 216. The application of impact is prevented. To reduce the speed at which the mold plunger 213 approaches the mold cavity 211, a limit switch (not shown) may be used.

  The time required from loading the moldable composition 216 into the mold cavity 211 to contacting the mold plunger 213 with the moldable composition 216 is preferably such that the moldable composition 216 is uniformly cured. Minimized to guarantee.

  As mold plunger 213 contacts progressively moldable composition 216, moldable composition 216 is subjected to a packing pressure of about 435 to 870 pressures per square inch (psi) and is maintained throughout the molding process. . Packing pressure is defined as the tonnage of pressure divided by the surface area of mold cavity 211 and the volume of moldable composition 216 in mold cavity 211.

  The movement of the mold plunger 213 in the direction of the mold hole 211 stops when the gap between the first mold part 210 and the second mold part 212 is about 0.1 to 0.5 mm determined in advance. . The second mold portion 212 is held in this position for about 20 to 60 seconds, and the moldable composition 216 is substantially cured.

  The heat generated from the first mold part 210 and the second mold part 212 vaporizes the moisture in the moldable composition 216, so that the moldable composition 216 expands. The moldable composition 216 fills the space between the first mold part 210 and the second mold part 212 in the mold cavity 211 by the applied pressure and its expansion. Moisture is released in the form of water vapor from a predetermined gap between the first mold part 210 and the second mold part 212.

  As the temperature of the moldable composition 216 increases, the adhesive within the moldable composition 216 begins to cure and the viscosity of the moldable composition 216 increases.

  FIG. 8 is an enlarged view showing a first mold part 210 and a second mold part 212 during the manufacture of a molded product according to one embodiment of the present invention. A predetermined gap of about 0.1 to 0.5 mm is maintained between the first mold part 210 and the second mold part 212, and a discharge port 218 is formed.

  Because heat is transferred directly from the first mold portion 210 and the second mold portion 212 to the outer surface layer 220 of the moldable composition 216, the outer surface layer 220 is at a higher temperature than the other portions of the moldable composition 216. Thus, it cures faster and forms a skin 222 around the moldable composition 216. The skin 222 acts as a thermal insulator and reduces heat flow from the first mold part 210 and the second mold part 212 to the moldable composition 216.

  As the moldable composition 216 expands, the outlet 218 closes, preventing the release of water vapor. Accordingly, as the moisture in the moldable composition 216 evaporates, the pressure in the moldable composition 216 increases, but cannot be removed. The trapped water vapor forms a plurality of vapor pockets 224 within the moldable composition 216 and facilitates the formation of a porous structure 226 within the moldable composition 216.

  Also, heat loss due to the loss of water vapor from the moldable composition 216 is prevented, resulting in an increase in the temperature of the moldable composition 216. The size of the plurality of vapor pockets 224 increases with increasing temperature of the moldable composition 216.

  If the first mold part 210 and the second mold part 212 are maintained at a temperature below 90 ° C., the amount of moisture that evaporates is reduced and fewer vapor pockets are formed. Along with this, a molded product with a higher density is produced. Conversely, the higher temperature first mold part 210 and the second mold part 212 will result in a lower density molded product.

  Also, the higher temperature first mold part 210 and second mold part 212 reduce the manufacturing time of the molded product. However, temperatures above about 180 ° C. cause the fibers in the moldable composition 216 to burn and excessively vaporize moisture in the moldable composition 216, resulting in the production of a molded product that is too dry. Not desirable.

  Accordingly, the temperature of the first mold part 210 and the second mold part 212 is preferably maintained at about 110 to 180 ° C. Embodiments show that if the temperature of the first mold part 210 and the second mold part 212 is within such a range, the temperature of the moldable composition 216 will be about 100 to 160 ° C. . Controlling the heat distribution within the moldable composition 216 allows the vaporization of moisture from the moldable composition 216 to reduce the vapor pockets 224 in the porous structure 226 to produce a uniform density molded product. It can be controlled to ensure a uniform distribution.

  When the pressure in the moldable composition 216 exceeds the external pressure, the closure at the outlet 218 is broken, and excess moldable composition 216, water vapor from the moldable composition 216, and adhesive cure Vapor from the evacuated vent 218 is released and the pressure in the moldable composition 216 is reduced.

  The gap C allows for the release of water vapor during the molding process, while maintaining sufficient pressure to fill the space between the first mold part 210 and the second mold part 212 in the mold cavity 211. Calculated. If the gap C between the first mold part 210 and the second mold part 212 is adjusted, the size of the discharge port 218, the pressure in the moldable composition 216 and its temperature, and the excess moldable composition to be discharged The volume of 216 can be controlled.

  For example, a larger gap C allows more water vapor and moldable composition to escape, resulting in less pressure build-up, reduced vapor expansion and higher density molded product production. Conversely, the smaller gap C suppresses the release of water vapor, induces vaporization of the vapor and produces a lower density molded product.

  However, a gap C that is too large is undesirable because the moldable composition 216 cannot close the outlet 218. Eventually, there is no accumulated pressure and the moldable composition does not fill the space between the first mold part 210 and the second mold part 212 in the mold cavity 211. When this occurs, the molded product produced does not have the desired shape.

  The size of the gap C also depends on the water content in the moldable composition 216. If the moldable composition 216 contains less moisture, the use of a smaller gap C is preferred, and if the moldable composition contains more moisture, more water vapor is released under these circumstances. For this reason, it is preferable to use a larger gap C.

  Molded products are produced when the moldable composition 216 is substantially cured, preferably about 90%. The moisture content of the moldable composition is preferably about 2 to 5%. Next, the plunger 206 is actuated to enlarge the gap C to about 10 mm, and all of the undesirable vapor expelled during the molding process is released.

  If the gap C is enlarged before the moldable composition 216 is substantially cured, the amount of moisture removed from the moldable composition 216 becomes insufficient, the molded product becomes soft and the mold cavity 211 and It becomes easy to adhere to the mold plunger 213. Therefore, when the mold plunger 213 is separated from the mold cavity 211, the outer surface layer 220 is distorted and the porous structure 226 is damaged. Thus, removal of moisture from the moldable composition 216 is critical in achieving a molded product that has sufficient strength to withstand stress and strain during processing and handling.

  Following the undesired vapor release, the gap C is approximately 0.05 to 0.3 mm to compress the molded product to the desired thickness and smooth the surface of the molded product to provide a good texture. It may be reduced and held in that state for about 15 to 60 seconds. Occurrence of further vaporization of moisture results in stable molded product manufacture.

  Subsequently, the plunger 206 is activated, the mold plunger 213 is withdrawn from the mold cavity 211, and the molded product is removed for subsequent processing. The molded product may be removed from the mold cavity 211 by a pick and place mechanism.

  The mold cavity 211 is preferably adapted to lift the molded product from the mold cavity 211 and assist in the removal of the molded product from the mold cavity 211 when the gap C is expanded to about 10 mm and undesirable vapor is released. Equipped with a protruding mechanism.

  9A and 9B are cross-sectional views illustrating an ejection mechanism 234 according to one embodiment of the present invention. FIG. 9A shows the ejecting mechanism 234 in a stationary state, and FIG. 9B shows the ejecting mechanism 234 in an operating state.

  First, referring to FIG. 9A, the ejection mechanism 234 is accommodated in the mold cavity 211 and positioned below the molded product 236. The ejection mechanism 234 includes a head 238 that is coupled to the base 240 by a shaft 242 and a spring 244 around the shaft 242. In the stationary state, the spring 244 is in an uncompressed state.

  In this embodiment, the ejector mechanism 234 is actuated by a pneumatic system (not shown). The shaft 242 may be equipped with an O-ring 246 to prevent air loss from the pneumatic system. In certain alternative embodiments, the ejection mechanism 234 may be actuated by a hydraulic system.

  When the gap C is enlarged or when the molded product 236 is taken out from the mold cavity 211, the pneumatic system is activated and a force is applied to the base portion 240, and the ejecting mechanism 234 moves in the direction X as shown in FIG. 9B. And spring 244 is compressed in this process. Accordingly, the molded product 236 is lifted from the mold cavity 211.

  The ejecting mechanism 234 returns to the stationary position shown in FIG. 9A by stopping the pneumatic system. In response, the spring 244 is released from its compressed state. When the spring 244 is extended, a force is applied to the base portion 240, and the protruding mechanism 234 is driven in the direction opposite to the direction X until reaching the rest position.

  The pneumatic or hydraulic system may be activated by the same limit switch that is used to reduce the speed at which the mold plunger 213 approaches the mold cavity 211.

  Referring again to FIG. 8, the moldable composition 216 may absorb heat too much and become burned when the adhesive and fibers are mixed, so the mold cavity 211 is extended over an extended period of time. Should not be left in. Also, if the moldable composition 216 is left in the mold cavity 211 for an extended period of time, excessive moisture is lost, which may cause cracks and strain.

  The degree of loading of the mold cavity 211 affects the density of the molded product. If the moldable composition 216 loaded into the mold cavity 211 is insufficient, the moldable composition 216 will allow sufficient space between the first mold part 210 and the second mold part 212 in the mold cavity 211. And the pressure sufficient to form the porous structure 226 is not accumulated. Thus, if the moldable composition 216 loaded into the mold cavity 211 is insufficient, a dense molded product with a high moisture content is produced.

  FIG. 10 is a flowchart illustrating a method 250 for manufacturing a molded product according to another embodiment of the present invention. The method 250 begins by loading 252 the mold cavity of the first mold part with a moldable composition. The mold cavity may be loaded 252 to about 90% of its capacity.

  A packing pressure of about 435 to 870 psi is applied 254 to the moldable composition for about 20 to 60 seconds to cure the moldable composition. Predetermined between the first mold part and the second mold part to allow discharge of excess moldable composition, water vapor and other vapors released during the curing of the moldable composition. A gap of about 0.1 to 0.5 mm is maintained 256. The first mold part and the second mold part are maintained at a temperature of about 110 to 180 ° C. The moldable composition compensates for heat loss when loaded into the mold cavity, and the first mold part and the second mold part are caused by thermal expansion of the first mold part and the second mold part. In order to prevent clogging, the first mold part is preferably maintained at a temperature about 20 ° C. above the temperature of the second mold part.

  The predetermined gap between the first mold part and the second mold part is preferably about 90% cured when the moldable composition is substantially cured to produce a molded product. 258 enlarged to about 10 mm. When water vapor and other vapors released during the curing of the moldable composition are substantially exhaled, the predetermined gap is between about 0.05 and 0.3 mm over about 15 to 60 seconds. Reduced to 260. This is done to compress the molded product to the desired thickness and smooth the surface of the molded product, which is then removed 262 from the mold cavity.

  Examples of processes and parameters that may be used in the manufacture of biodegradable pallets according to one embodiment of the present invention are shown in Tables 2A and 2B.

本発明の明細書及び実施について考察すれば、当業者には、本発明の他の実施形態が明らかとなるであろう。明細書本文及びクレームに使用されている「を備える」という用語、及び「を備える」という用語の諸形態は、本発明の変形または追加物を除外するように意図されたものではない。さらに、所定の用語法は説明を明確にするために使用されたものであり、本発明の限定を目的とするものではない。これまでに述べた実施形態及び好適な特徴は例示として考察されるべきものであり、本発明は添付の請求の範囲によって規定される。

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. The terms “comprising” and forms of the term “comprising” used in the specification and claims are not intended to exclude variations or additions of the invention. Furthermore, certain terminology is used for clarity of explanation and is not intended to limit the invention. The embodiments and preferred features described so far are to be considered exemplary and the invention is defined by the appended claims.

It is a perspective view which shows the pallet by one Embodiment of this invention. It is a bottom view which shows the pallet main body by one Embodiment of this invention. 1 is a perspective view showing a skid according to an embodiment of the present invention. It is sectional drawing which shows the connection means by one Embodiment of this invention. 2 is a flowchart illustrating a method for preparing a moldable composition according to an embodiment of the present invention. It is a flowchart which shows the preparation method of the fiber mixture by one Embodiment of this invention. 1 shows a press for producing a molded product according to an embodiment of the invention. FIG. 4 is an enlarged view showing a mold cavity and a mold plunger during manufacture of a molded product according to an embodiment of the present invention. It is sectional drawing which shows the protrusion mechanism of a stationary state by one Embodiment of this invention. It is sectional drawing which shows the protrusion mechanism of the operation state by one Embodiment of this invention. It is a flowchart which shows the manufacturing method of the molded product by one Embodiment of this invention.

Claims (79)

The pallet body,
A skid for reinforcing the pallet body;
Means for connecting the pallet body and the skid,
The pallet body and the skid are molded from a moldable composition comprising about 40-60% by weight fiber mixture and about 15-45% by weight adhesive.   The pallet of claim 1, wherein the moldable composition has a moisture content of less than about 20%.   The pallet according to claim 2, wherein the water content of the moldable composition is about 4-15%.   The pallet of claim 2, wherein the moisture content of the fiber mixture is less than about 15%.   The pallet of claim 3, wherein the moldable composition further comprises about 40 wt% or less adhesive.   The pallet according to claim 5, wherein the adhesive is one or more of the group consisting of a curing agent, a glidant and a release agent.   The pallet of claim 1, wherein the fiber mixture includes a plurality of fibers, each of the plurality of fibers being up to about 50 mm in length.   The pallet of claim 7, wherein each of the plurality of fibers is up to about 2 mm thick.   The pallet of claim 8, wherein the ratio of length to thickness of each of the plurality of fibers is about 2: 1 to 25: 1.   The pallet of claim 1, wherein the fiber mixture further comprises about 5-30 wt% oil palm fibers.   The pallet of claim 1, wherein the fiber mixture further comprises one of the group consisting of oil palm fiber, beer malt, sugarcane pulp, plasticizer, reinforcing agent and impact modifier.   The pallet according to claim 1, wherein the adhesive is a thermosetting resin.   The pallet according to claim 12, wherein the adhesive is an amino resin.   The pallet according to claim 12, wherein the adhesive is melamine.   The pallet according to claim 14, wherein the adhesive is one of the group consisting of melamine formaldehyde and melamine urea formaldehyde.   The pallet according to claim 1, wherein the pallet body includes a load-bearing member having legs.   The pallet of claim 16, wherein the load bearing member has a substantially constant overall wall thickness of about 3-5 mm.   The pallet according to claim 16, wherein the load bearing member includes a plurality of ribs.   The pallet of claim 18, wherein each of the plurality of ribs comprises an open groove.   The pallet according to claim 19, wherein the open groove has a tapered groove wall.   The pallet of claim 18, wherein each of the plurality of ribs is designed to have a draft of about 6-12 ° from a normal to the surface of the load bearing member.   The pallet according to claim 16, wherein the leg is formed as a concave depression in the load bearing member.   The pallet of claim 16, wherein the legs taper inward toward the base.   24. The pallet of claim 23, wherein the legs are designed to have a draft of about 11-12 [deg.] From a normal to the surface of the load bearing member.   24. A pallet according to claim 23, wherein the legs are designed to have a minimum vertical height of about 95 mm.   24. A pallet according to claim 23, wherein the base is provided with a blind hole.   27. The pallet of claim 26, wherein the blind hole is designed to have a draft of less than about 0.5 [deg.] From a normal to the surface of the load bearing member.   The pallet according to claim 16, wherein a first fillet is formed at a location where the leg and the load bearing member intersect.   The pallet according to claim 16, wherein fins are provided along an outer periphery of the load bearing member.   The pallet according to claim 1, wherein the skid includes a frame formed from a plurality of tethers.   The pallet according to claim 30, wherein a second fillet is formed at a joint where the plurality of connecting materials are joined.   27. The pallet of claim 26, wherein the skid has a protruding plug corresponding to a blind hole in the base of the leg.   The pallet of claim 32, wherein the blind hole connects with the protruding plug.   34. The pallet of claim 33, wherein an outer peripheral dimension of the protruding plug is about 0.05 mm to 0.1 mm larger than an outer peripheral dimension of the blind hole.   35. A pallet according to claim 34, wherein when a force connecting the blind hole and the protruding plug is applied, the skid is secured to the pallet body by an interference fit.   33. A pallet according to claim 32, wherein the protruding plug is designed to have a draft of less than about 0.5 [deg.] From a normal to the surface of the skid.   The pallet of claim 1, wherein the pallet is designed to cover at least about 60% of the upper carrier.   The pallet of claim 1, wherein the pallet is designed to cover at least about 35% of the lower platform. A method for producing a biodegradable pallet comprising:
Providing a biodegradable moldable composition containing about 40-60% by weight fiber mixture and about 15-45% by weight adhesive;
Loading the mold cavity with the moldable composition to about 90% of its capacity;
Applying a packing pressure of about 435-870 psi to the moldable composition;
Maintaining a predetermined gap of about 0.1 to 0.5 mm between a first mold part and a second mold part defining the mold cavity;
Removing the molded product from the mold cavity when the moldable composition is substantially cured.   40. The method of claim 39, wherein the pressure is applied for about 20-60 seconds.   41. The method of claim 40, wherein the first mold part and the second mold part are maintained at a temperature of about 110-180C.   42. The method of claim 41, wherein the temperature of the first mold part is maintained at about 20 degrees Celsius above the temperature of the second mold part.   41. The method of claim 40, further comprising expanding the predetermined gap between the first mold part and the second mold part when the moldable composition is about 90% cured. .   44. The method of claim 43, wherein the predetermined gap is enlarged to about 10 mm.   45. The method of claim 44, further comprising compressing the molded product to a desired thickness.   46. The method of claim 45, further comprising leveling the surface of the molded product. Compressing the molded product to the desired thickness and leveling the surface of the molded product,
48. The method of claim 46, further comprising reducing the predetermined gap to about 0.05 to 0.3 mm.   48. The method of claim 47, wherein the predetermined gap is reduced in about 15-60 seconds.   40. The method of claim 39, wherein the moldable composition has a moisture content of less than about 20%.   50. The method of claim 49, wherein the water content of the moldable composition is about 4-15%.   50. The method of claim 49, wherein the moisture content of the fiber mixture is less than about 15%.   51. The method of claim 50, wherein the moldable composition further comprises up to about 40% by weight additive.   53. The method of claim 52, wherein the additive is one or more of the group consisting of a curing agent, a glidant and a release agent.   40. The method of claim 39, wherein the fiber mixture comprises a plurality of fibers, each of the plurality of fibers being up to about 50 mm in length.   55. The method of claim 54, wherein each of the plurality of fibers is up to about 2 mm thick.   56. The method of claim 55, wherein the length to thickness ratio of each of the plurality of fibers is about 2: 1 to 25: 1.   40. The method of claim 39, wherein the fiber mixture further comprises about 5-30% by weight of oil palm fibers.   40. The method of claim 39, wherein the fiber mixture further comprises one of the group consisting of oil palm fibers, beer malt, sugarcane pulp, plasticizers, reinforcing agents and impact modifiers.   40. The method of claim 39, wherein the adhesive is a thermosetting resin.   60. The method of claim 59, wherein the adhesive is an amino resin.   60. The method of claim 59, wherein the adhesive is melamine.   62. The method of claim 61, wherein the adhesive is one of the group consisting of melamine formaldehyde and melamine urea formaldehyde. Preparing the moldable composition comprises:
Individually calibrating each component of the moldable composition;
40. mixing the components of the moldable composition in a mixer to form a substantially homogeneous and well-coated moldable composition.   64. The method of claim 63, wherein providing the moldable composition further comprises mixing each liquid component of the moldable composition in a second mixer to form a liquid mixture. .   65. The method of claim 64, wherein providing the moldable composition further comprises spraying the liquid mixture into the mixer.   66. The method of claim 65, wherein the mixer is operated at a rotor speed of about 29 rpm.   40. The method of claim 39, wherein an outlet is provided by maintaining a predetermined gap between individual portions of the mold adjacent to the moldable composition.   68. The method of claim 67, wherein the outlet is temporarily blocked by the moldable composition in the mold to temporarily prevent the release of water vapor for a predetermined period of time.   69. The method of claim 68, wherein the water vapor content is controlled to produce vapor bubbles in the moldable composition and thereby produce a porous molded product of a predetermined density. A method for manufacturing a biodegradable pallet comprising:
Loading the mold cavity with a biodegradable moldable composition comprising about 40-60% by weight fiber mixture and about 15-45% by weight adhesive to about 90% of the volume of the mold cavity; ,
Activating the mold to apply a packing pressure in the range of 435-870 psi to the moldable composition in the mold cavity;
Responsive to the pressure in the moldable composition, the water vapor content and thus the pressure in the composition is set to be controlled as predetermined, thereby having a predetermined density and strength. Providing a water vapor outlet for producing a molded product;
When the moldable composition is substantially cured, removing the molded product from the mold cavity;
Including methods.   71. The method of claim 70, wherein the outlet is provided by maintaining a predetermined gap between individual portions of the mold adjacent to the moldable composition.   71. The method of claim 70, wherein the outlet is temporarily plugged by the moldable composition in the mold to temporarily prevent the release of water vapor for a predetermined period of time.   71. The method of claim 70, wherein the water vapor content is controlled to produce vapor bubbles in the moldable composition and thereby produce a porous molded product of a predetermined density.   71. The method of claim 70, further comprising expanding the predetermined gap between the first mold part and the second mold part when the moldable composition is about 90% cured. .   75. The method for manufacturing a pallet according to claim 74, wherein the predetermined gap is enlarged to about 10 mm.   The method for manufacturing a pallet according to claim 75, further comprising a step of compressing the molded product to a desired thickness.   77. The method for manufacturing a pallet according to claim 76, further comprising a step of leveling a surface of the molded product. Compressing the molded product to the desired thickness and leveling the surface of the molded product,
78. The method of manufacturing a pallet according to claim 77, further comprising the step of reducing the predetermined gap to about 0.05 to 0.3 mm.   A pallet manufactured by the method according to any of claims 39 to 73.

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