A method for manufacturing medium and high-density fiberboard with SOY components

Abstract

The present disclosure relates to a method for making fiberboard with a system comprising a plug flow screw, a cooker, a refiner, a blowline, and a press. The method comprises a), introducing woodchips to the plug flow screw; b). passing the woodchips through the plug flow screw to the cooker, c). adding a soy component having a protein dispersibility index (PDI) less than 50 to the cooker, d). passing the woodchips from step c) through the refiner to produce glued refiner wood fibers, e). passing the glued refiner wood fibers from d) through the blowhne to produce pressable wood fibers, f). optionally adding a water retardant, and g). pressing the pressable wood fibers under heat and pressure to form the fiberboard.

Description

A METHOD FOR MANUFACTURING MEDIUM AND HIGH-DENSITY FIBERBOARD WITH SOY COMPONENTSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 632,069, filed April 10, 2024, which is incorporated by reference herein in its entirety.BACKGROUND

[0002] Medium density fiberboard (MDF) and high density fiberboard (HDF) are engineered wood products that are utilized in furniture, flooring, cabinetry and other end-use applications. Historically, wood adhesives such as phenol-formaldehyde resins (PF) and ureaformaldehyde resins (UF) have been utilized. There are at least two concerns with PF and UF resins. First, volatile organic compounds (VOC), such as formaldehyde, are generated during the manufacture of MDF and HDF. Additionally, formaldehyde may be released from boards made from UF when the boards are exposed to high heat and humidity. The formaldehyde released from board made from PF and UF are undesirable.SUMMARY OF THE INVENTION

[0003] Medium density fiberboard (MDF) and high density fiberboard (HDF) typically are manufactured using a manufacturing system that includes a plug flow screw, a cooker, a refiner, a blowline, a dryer and a press (where the fibers and adhesive utilized are cured through the application of heat and pressure).

[0004] Typically, the adhesives used comprise urea formaldehyde (UF) or melamine urea formaldehyde (MUF). Due to the high heat and pressure present in the cooker and the refiner, the adhesives typically are added to the blowline. At least in part due to the high heat and pressure degrading UF and MUF based adhesives [precuring = condensation / polymerization],

[0005] It has been surprisingly discovered that a binder based on a soy component, such as soy flour, soy flake, and / or soy meal can advantageously be added to the cooker or just upstream of the cooker and provide a MDF or HDF articles (MDF and HDF collectively referred to as Fiberboard, herein) having excellent physical properties, such as density, interior bond strength, thickness swell, water adsorption, modulus of elasticity (MOE) and / or modulus of rupture (MOR).

[0006] It has been surprisingly discovered that soy components with a low protein dispersibility index (PDI) (e.g., less than 50) show benefits even when added before the plug flowscrew during manufacturing in comparison to the more costly high PDI components that are predominantly used in other soy -based concepts. In this fashion, it is thought less binder is lost by the squeeze water of the screw press.

[0007] Additionally, it was surprisingly found that the use of a water retardant, such as glycerol, sorbitol, maltitol, and mixtures thereof may further improve the water-resistant properties of the Fiberboards (such as thickness swell and water absorption) when added to the blowline or cooker in conjunction with a soy component being added to the cooker. Preferably, the water retardant, if added, is added to the blowline.

[0008] Further, an anti -foaming agent, a base, a sulfite agent, and a surfactant may also be added to the cooker or blowline to enhance the physical properties of Fiberboard articles made from the resulting glued fibers and / or processability of the glued fibers during the manufacture of Fiberboard articles, such as panels.

[0009] If desired, a base may be added to the blowline, if desired to maintain a neutral to slightly basic pH in the blowline and drier. Typically, the base comprises sodium hydroxide (NaOH), magnesium oxide, potassium hydroxide (KOH), or mixtures thereof.

[0010] In one aspect, a method is described for making fiberboard using a system comprising a plug flow screw, a cooker, a refiner, a blowline, a dryer and a press, the method comprising: a) introducing woodchips to the plug flow screw; b) passing the woodchips through the plug flow screw to the cooker; c) adding a soy component having a PDI less than 50 selected from the group consisting of soy flour, soy meal, soy flake, and mixtures thereof to the cooker; d) passing the woodchips from step c) through the refiner to produce glued refiner wood fibers; e) passing the glued refiner wood fibers from d) through the blowline to produce pressable wood fibers; f) optionally adding a water retardant selected from the group consisting of glycerol, sorbitol, maltitol, and mixtures thereof to the blowline; and g) pressing the pressable wood fibers under heat and pressure to form the fiberboard.

[0011] Typically, the glued wood fibers are heated to from 140°C to 260°C, preferably from 160°C to 240°C (for example, from 160°C to 220°C) in the press; and at a pressure of from 20 to 400N / cm2, preferably from 100 to 400N / cm2(for example, from 130 to 380N / cm2) to cure the wood fibers and soy component together and form the fiberboard, or other shape. Press factorof 8-12s / mm - describes the duration of pressing per mm of the end thickness of the board. There is also an optional but typically utilized prepressing step to remove the air. For example, one may utilize a Hofer OK 426 lab press at maximum 15 bar for 60 seconds.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein.

[0013] FIG. 1 is a description of the typical production process for a standard MDF material.DETAILED DESCRIPTION OF THE INVENTION

[0014] Reference will now be made in detail to certain embodiments of the disclosed subject matter. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.

[0015] In this document, the terms “a,” “an,” or “the” are used to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” has the same meaning as “A, B, or A and B.” In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.

[0016] The term “substantially” as used herein refers to a majority of, or mostly, as in at least about 90%, 95%, 99,5%, or 100%. The term “substantially free of’ as used herein can mean having none or having a trivial amount of, such that the amount of material present does not affect the material properties of the composition including the material, such that about 0 wt% to about 5 wt% of the composition is the material, or about 0 wt% to about 1 wt%, or about 5 wt% or less, or about 0 wt%.

[0017] According to various aspects of the instant disclosure, an aqueous dispersion binding agent is described together with Fiberboard and method for making such Fiberboard (e.g., MDF and HDF).

[0018] The Fiberboard can be used to make flooring, furniture, cabinets, etc.Soy Component:

[0019] The soy component is selected from the group consisting of soy flour, soy meal, soy flake, and mixtures, thereof. The soy component has been crushed and defatted using methods known to ordinary skill in the art, such as solvent extraction of oil from the material using, hexane and other suitable solvents. The oil content of the soy component typically is from 0. 1 to 2%.

[0020] The soy component typically comprises from 5 to 20 dry weight percent based on the dry weight of wood chips introduced in step a) (e.g., from 5 dry weight percent to 15 dry weight percent of soy component (e.g., 7 dry weight percent to 15 dry weight percent, based on the dry weight of the wood chips in step a).

[0021] The soy component typically has a protein content of from 35 wt% to 65 wt% (for example, from 40 wt% to 60 wt%). The soy component includes non-protein constituents such as a carbohydrate.

[0022] The soy flour and soy meal typically have an average diameter of 3 mm or less, for example an average diameter of 2 mm or less. Soy flakes are typically 7 mm or less.

[0023] The soy component may be added to the cooker in solid or liquid form. Typically, the soy component will be added to dry powder or dry flake form. Alternatively, the soy component may be added as an aqueous slurry or a thick pumpable liquid.

[0024] A screw or positive displacement pump may be utilized to add the soy component to the cooker.

[0025] The term “added to the cooker” includes adding the soy component to a fluid conduit that is operably connected to the cooker, so that adding it to the fluid conduit will cause it to make its way to the cooker. However, the soy component is added downstream of the plug screw. This will help minimize soy protein loss to the squeeze water removed by the plug screw.

[0026] It was surprising found that the soy component could be added to the cooker and still provide Fiberboard with comparable and competitive properties with Fiberboard where the binder system is added downstream of the cooker (for example, in the blowline).

[0027] While not wanting to be bound by theory, it is believed that the usefulness of the protein in the soy component as a wood adhesive is it is not significantly degraded (nor significantly polymerized) by the high heat and steam in the cooker, and that the wood adhesive properties of the carbohydrates in the soy component may be improved by the high heat and steam in the cooker through partial gelatinization of the starch components.

[0028] Soy flour and soy meal have a protein dispersibility index (PDI) from 10 to 90. Surprisingly and unexpectedly, it was discovered that it is of advantage to select a low PDI meal instead of the more costly, high PDI flour, that is predominantly used in current soy-based concepts, especially if added before the plug screw press. Careful choice of protein source can lead to less binding components being lost through the squeeze water of the plug screw press.

[0029] In some aspects, the soy protein source has a PDI of less than 50, or less than 30, or less than 25. In some aspects, the soy protein source has a PDI between 10 and 50 or between 10 and 30.

[0030] If soy flour is utilized, in some aspects the soy flour is selected that passes through a screen sized 100-mesh screen to a 635-mesh screen or a 100-mesh screen to a 400-mesh screen. For example, the soy flour typically has a mesh size of from 100 to 300, or from 100 to 200.

[0031] It has been surprisingly and unexpectedly found that adding the soy component to the cooker and adding water retardant to the blowline produces Fiberboard panels having competitive properties to Fiberboard made using UF Binder.Water Retardant:

[0032] A water retardant, such as polyamidoamine-epichlorohydnn (PAE), polymeric methylene diphenyl diisocyanate (PMDI), epoxidized vegetable oils, (vegetable) wax emulsions, glycerol, sorbitol, maltitol, and mixtures thereof are added to the blowline to further improve the water-resistant properties of the Fiberboards (such as thickness swell and water absorption).

[0033] Typically, from 0- to 8% dry weight percent water retardant is added based on the dry weight of wood chips introduced in step a) (e.g., from 0 dry weight percent to 6 dry weight percent of water retardant (e.g., 0%-5%weight percent, from 0%-4% dry weight percent) based on the dry weight of the wood chips added in step a).

[0034] Preferably, the water retardant is added as a liquid; typically, the water retardant is added as an aqueous solution or dispersion to the blowline. For example, an aqueous solution or dispersion comprising from 10 to 85 wt% water retardant may be added to the blowline.

[0035] The glycerol and sorbitol, if present, typically are present in a weight ratio of from 0: 1 to 1 :0 glycerol component to sorbitol (for example from 0.1 :1 to 1:0.1 glycerol component to sorbitol).

[0036] Preferably, glycerol is utilized without the use of sorbitol or other polyols.

[0037] The glycerol component may be in the form of crude glycerol. An example of a crude glycerol is a mixture including 10 to 20 wt% water (for example 15 wt%), 3 wt% to 5 wt%NaCl (for example 3 wt% to 4 wt%) and 75 wt% to 92 wt% glycerol (for example 80 wt% to 90 wt%) based on the dry substance content. A crude glycerol may include additional materials known to one of skill in the art. Advantageously, it is found that binder systems including crude glycerol can yield superior or at least equivalent performance to a binder system using pure glycerol.

[0038] In some aspects, the glycerol component can include less than 3 wt%, less than 2 wt%, or less than 1 wt% NaCl. In some aspects, the glycerol can be a technical grade glycerol that includes a high concentration of glycerol and less than 1 wt% methanol, less than 0.5 wt% methanol, or less than 0.1 wt% methanol and less than 1 wt% NaCl, less than 0.5 wt% NaCl, or less than 0. 1 wt% NaCl. In some aspects, the technical glycerol includes at least 98 wt% glycerol.Sulfite agent:

[0039] A sulfite agent is optionally added. The sulfite agent typically comprises sodium sulfite, sodium bisulfite, sodium metabisulfite, or mixtures thereof. The sulfite agent typically comprises from 0,005% to 1.0 wt% based on the dry weight of the wood chips added in step a) (for example from 0.025 to 0.8 wt%, from 0.05 to 0.6 wt%, or from O. lto 0.3 wt% based on the dry weight of the wood chips added in step a).

[0040] The sulfite agent can help to increase the strength of the resulting Fiberboard and help increase the increase the modulus of rupture, modulus of elasticity, internal bond strength, or a combination thereof of the Fiberboard panes. Where present, a ratio of sodium sulfite to soy component is in a range of from 1: 100 to 12: 100 or 1: 100 to 4:100. The sulfite agent preferably is introduced into the blowline.Surfactant:

[0041] A surfactant is optionally added. The surfactant typically comprises from 0.005 to0.4 wt% based on the dry weight of the wood chips added in step a) (for example, from 0.01% to 0.1 wt% based on the dry weight of the wood chips added in step a).Substantially -free of urea formaldehyde:

[0042] The process is substantially free of a urea-formaldehyde. For example, the binding system utilized typically includes less than 2 wt% of urea-formaldehyde, less than 1.5 wt% of urea-formaldehyde, or less than 1 wt% urea-formaldehyde. This will enable the board to bemanufactured with low emissions during manufacture and provide a Fiberboard that does not emit significant formaldehyde when exposed to high temperatures and high humidity.

[0043] There are a number of disadvantages associated with using urea-formaldehyde. For example, addition of water, in high temperature, cured urea-formaldehyde can hydrolyze and release formaldehyde, this weakens the glue bond and can be toxic. Additionally, urea- formaldehyde adhesives both during and before curing can release formaldehyde and other volatiles. This will require urea-formaldehyde to be used in well-ventilated areas and can cause air emission issues.

[0044] The materials described herein can address at least some of these drawbacks and, in particular, prevent the outgassing of substantially any formaldehyde.Making the Fiberboard:

[0045] A Fiberboard manufacturing process includes the following described main equipment and unit operations as described in Figure 1 together with additional unit operations and equipment know n to one of ordinary skill in the art.

[0046] Referring to FIG 1, the major unit operations of a Fiberboard panel manufacturing line are shown. A conveyor 11 typically transfers large wood chips that were previously washed to plug screw 13 that compresses the large wood chips to form a plug of wood chips that are transferred into cooker 15. The water content (also known as wood moisture in the art) of the large wood chips carried by the conveyor is typically high (e.g., 50% - 200% by weight water). The plug of wood chips helps maintain a back pressure on the cooker 15 to prevent blowback of wood chips and other materials present in cooker 15 into plug screw 13. Plug screw 13 also removes much of the water from the wood chips and sends the water removed (squeeze water) to wastewater treatment.

[0047] A soy component is added to cooker 15 (or to a fluid conduit that is connected to cooker 15) (but downstream of plug screw 13 so that the soy component will enter cooker 15). A screw, pressure pump or similar device can be utilized to introduce the soy component into cooker 15 at sufficiently high pressure. As mentioned earlier, the soy component may be introduced as a powder, flake, liquid, slurry or in any other form that can be readily introduced into cooker 15 at sufficient high pressure.

[0048] In cooker 15, the wood chips and soy component typically are cooked at pressure (about 5-7 bar) and at 170°C for 3-8 minutes through the direct introduction of steam into cooker 15. The cooked wood chips and soy component exit cooker 15 and are sent through refiner 19.

[0049] Typically, a swell-retardant agent, such as a wax emulsion, (from 0.5 wt% to 1.5 wt% on a dry basis of the wood chips and wax) is added after cooker 15 and prior to refiner 19. Alternatively, a swell-retardant agent may be added to blowline 21.

[0050] Refiner 19 typically comprises a disc refiner with a gap of 0.12 mm to 0.16 mm. As the cooked wood chips and soy component pass through refiner 19 they are converted to refiner wood fibers that have a greatly reduced size compared the wood chips that entered refiner 19 and that are at least partially coated with the soy component. The processes that occur in refiner 19 are sometimes referred to as defibration process. The aspect ratio of the refiner wood fibers existing refiner 19 is large, the refiner wood fibers are fine, and the fibers are relatively homogeneous in size with respect to each other. Refiner wood fibers exiting refiner 19 still have a significant moisture content and are at least partially coated with the soy component.

[0051] Refiner wood fibers exits refiner 19 and are sent through an outlet line to a “blowline 21.” Blowline 21 connects the outlet of refiner 19 to an area where the pressure within the system is greatly reduced. Typically, the blowline 21 is connected to a dryer 23 that typically comprises a larger diameter pipe that is heated along its external wall.

[0052] If utilized, water retardant typically is introduced into blowline 21 downstream of refiner 19 and prior to the pressure drop taking place in blowline 21 (near dryer 23). This can be achieved by introducing the water retardant into blowline 21 upstream of the area where the pressure drop and steam explosion takes place.

[0053] At the end of blowline 21, the pressure is greatly reduced rapidly, thereby causing a steam explosion of water present with the refiner wood fibers and water that may be introduced into blowline 21 (such as water present within water retardant that may be added to blowline 21 (and / or anti-foaming agent, a base, a sulfite agent and / or a surfactant that may be added to blowline 21)). The steam explosion further reduces the sizing variability of the fibers to produce wood fibers that are much finer than the refiner wood fibers exiting refiner 19 (and have soy components and water retardant and any other materials added to the process on them or absorbed by the fibers (e.g., surfactant, anti-foaming agent, etc.)).

[0054] The glued wood fibers typically are dried in a drier 23 (e.g., to a 7-8 wt% moisture level). The dried glued wood fibers may be stored in glued fiber storage. When desired, the dried glued wood fibers are evenly distributed on a continuously running conveyor belt or similar spreading operation 25 (typically in random directions) to form a mat. The mat comprising glued wood fibers is further shaped and typically pre-pressed 26 (at lower temperatures and pressures than used in final press 27 before being introduced to a final press 27 where high heat and pressurecure the mat comprising glued wood fibers into a Fiberboard. The temperatures utilized to form and cure the panels in the final pressing operations typically range from 140°C to 260°C. The pressures utilized ty pically range from 25-380N / cm2in an industrial system. A range of 140°C- 200°C at lObar is typically utilized in lab scale press. In both cases, the press factor is between 8- 12s / mm. The two main types of final presses utilized are a continuous press and multi-opening presses.

[0055] Additional finishing steps such as calibration of the raw panels, sanding, trimming, and sizing of the Fiberboard to produce the final Fiberboard panels using techniques known to one of skill in the art. Typically, a coating or laminate is applied to the Fiberboard near the end of the manufacturing process.

[0056] Physical Properties of the Fiberboard Panels that can be measured are listed in Table 1 below.Table 1.

[0057] Examples of desirable physical properties of the Fiberboard described herein can include the product’s internal bond strength (IB), density, modulus of rupture (MOR), modulus of elasticity (MOE), Thickness Swell Percent (Thickness swell%), or a combination thereof as measured for example in the Working Examples. The modulus of rupture of the Fiberboard product measures the amount of force required to result in rupturing the Fiberboard product. The modulus of rupture can be measured, for example, according to ASTM D1037-06a. While the modulus of rupture value can depend on a variety of factors, including the Fiberboard product’s density, length, width, thickness, or a combination thereof, the modulus of rupture can generally be at least 800 psi or in a range of from 800 psi to 2000 psi or from 800 psi to 1900 psi.

[0058] The modulus of elasticity is a quantity that measures Fiberboard product’s resistance to being deformed elastically (e.g., non-permanently) when a stress is applied to it. The modulus of elasticity can be measured, for example, according to ASTM D1037-06a as describedin the examples herein. The modulus of elasticity value typically depends on a variety of factors, including the Fiberboard product’s density, length, width, thickness, or a combination thereof.

[0059] The thickness swell% is a quantity that measures the Fiberboard product’s resistivity to water penetration. The higher the value, the greater the amount of water that is penetrated. This can result in the Fiberboard product swelling or otherwise deforming. For example, the Fiberboard product may expand past a desired amount. This can be undesirable, if the Fiberboard product has precise features such as bore holes, flanges, grooves, or the like, that are designed to fit precisely with a corresponding feature on another product. The thickness swell% value can be measured, for example, according to ASTM D1037-06a as described in the examples herein. According to some aspects, the thickness swell% after soaking the Fiberboard in water for two hours can be as low as zero. However, other acceptable values include those in a range of from 5% to 40% or from 15% to 25%, measured after soaking the Fiberboard in water for two hours.

[0060] As discussed above, a swell-retardant agent may be introduced onto to refiner fibers. The swell-retardant agent typically can include a wax emulsion that can sustain (e.g., remain stable) even the pHs being used and high temperature environment as utilized in the manufacture of Fiberboard panels descnbed herein. Where present, the swell-retardant can be from 0.1 wt% to 2 wt% or typically from 0.5 wt% to 1.5 wt% of the dry weight of the swell retardant agent and wood fiber present.

[0061] The internal bond strength is a quantity that measures a material’s ability to resist rupturing in the direction perpendicular to the plane of the material’s surface. The internal bond strength can be measured by ASTM D 1037-06a, as described in the examples herein. The Fiberboard panels shows internal bond strength values of at least 40 psi, in a range of 40 psi to 120 psi or 40 psi to 90 psi or 50 psi to 90 psi, or 50 psi to 75 psi.

[0062] A benefit of using the soy component, water retardant (and other optional materials) and the methods described herein to manufacture Fiberboard panels, is that the properties of the Fiberboard panels, ty pically are generally comparable to those of Fiberboard panels that are made using a urea-formaldehyde (UF) binder.

[0063] The wood used to make the Fiberboard described herein can include one or more wood particles, one or more wood components, one or more wood chips, or one or more wood strands. The wood can include a wood material such as pine, hemlock, spruce, aspen, birch, maple, or mixtures thereof. All the wood is treated by a Fiberboard manufacturing process as described above and as further known to one of ordinary skill in the art.WORKING EXAMPLES

[0064] Various aspects of the present disclosure can be better understood by reference to the following Working Examples which are offered by way of illustration. The present disclosure is not limited to the Working Examples given herein. The weight percentages (wt%) indicated refer to weight percent of the indicated component based on the total weight of the material or formulation being referred to, unless otherwise indicated.Table 2. MaterialsMaking Medium Density Fiberboard (MDF) Panels:

[0065] Medium Density Fiberboard panels are manufactured at pilot scale using the method described above for Fiberboard and as depicted in FIG. 1., and as more fully described below. The average throughput of materials used to make the MDF through the equipment was 40 kg / h.

[0066] Wood Chips and the desired soy component (as indicated in Table 2, above) are loaded into a hopper and carried by an elevator / conveyor to a plug flow screw, where the Wood Chips as they move forward are compressed into a plug. As the Wood Chips move forward through the screw, water (squeeze water) is removed from the Wood Chips to lower the moisture content. As moisture content may vary seasonally approximately 30% to 50% of the water weight may be lost in this stage. Any binder or soy component dissolved in the squeeze water will also be disadvantageous^ lost.

[0067] The wood chip plug (containing soy component) flows into cooker 15 where direct steam is introduced at 170°C and 8 to 9 bars. The wood chip plug prevents the material in cooker 15 from backflowing into the plug flow screw. The wood chips remain in cooker 15 for from 3 to 4 minutes and are then transported to the refiner 19 (having a 0.14 mm gap) where a defibration process acts on the cooked wood chips to produce refiner wood fibers. Prior to entering refiner19, one weight percent (1 wt%) (on a dry basis) Wax Emulsion is added to the cooked Wood Chips.

[0068] The refiner wood fibers exit refiner 19 and are transported toward blowline 21. Water retardant and other materials as indicated in Table 2 (and for the control UF-Binder) are added to blowline 21. The weight percent of the binder system used for each sample MDF panel are indicated in Table 3, below. And a control was also made that was binder free. In blowline 21 near the dyer, the pressure is dropped rapidly to atmospheric pressure and thereby causes the water present to flash to steam and further fiberize the wood to reduce the size of the glued wood fibers.Table 3.

[0069] Urea formaldehyde (UF) binders are well known in the industry and can be purchased from a variety of sources. The UF Binder used in the examples is set out as follows. The base binder is an aqueous mixture of urea and formaldehyde commercially available from BASF (K-333). It was mixed with an additional (but optional) amount of urea (7.2% dry basis of urea based on total weight of the K-333 binder). In addition, 3% of an ammonium sulfate hardener was added based on the total weight of the K-333 binder. This mixture was then utilized in the formulations at a 12% dosage based on the dry weight of the wood.

[0070] As indicated in Tables 4, Bio-Binder Composition was prepared by mixing the ingredients below into water.

[0071] As indicated in Table 5, Binder 2 was prepared by mixing the ingredients below into water.Table 4.Table 5.

[0072] The glued wood fibers are dried in dryer 23 to a moisture content of from 7-13 wt%. The glued wood fibers are manually loaded into wooden forming frames (580 mm by 520 mm). The glued wood fibers are pre-pressed to compact the glued wood fibers and then pressed at a pressure of 15 bar for sixty seconds using a Hofer OK 426 press and heated to a temperature of 185°C for 8 to 10 second. The final MDF panels measure 580 mm by 520 mm by 3 mm thick and have a target density of 820 kg / m3. The panels are trimmed and tested for mechanical properties.

[0073] The properties of the resulting panels are set forth below in Table 6.Table 6.*The parameters of Table 6 were measured by the EN and DIN standard methods identified.

[0074] As can be seen in Table 6, even though significant soy component was discharged by plug screw 13 through the squeeze water, the Fiberboard manufactured still provided significant binding properties and show that the soy component can effectively be added to cooker 15 (without negative polymerization or deterioration). It is estimated that between 5 and 50 of the weight % of the soy component was lost with the squeeze water. By adding the soy component downstream of plug screw 13 the loss of soy component by plug screw 13 through the squeeze water can be eliminated. This will result in Fiberboards having higher internal bond strength, MOE, and MOR than Fiberboards made with the same Soy Component and same amount of Soy Component introduced at the inlet of plug screw 13.

[0075] And, as can be seen from Example 1C, addition of water retardant into the blowline provides Fiberboard with improved water retardancy properties compared to Fiberboard made with similar binder system, but without the water retardant added (see Examples ID).

[0076] Finally, as can be seen from Table 6 (and the description above regarding adding the soy component to cooker 15 and downstream of plug screw 13), the properties of Fiberboard made with the addition of a soy component directly to cooker 15 with the addition of a waterretardant to the blowline will perform competitively with the properties of Fiberboard made with UF Binder.

Claims

CLAIMSWhat is claimed is:

1. A method for making fiberboard with a system comprising a plug flow screw, a cooker, a refiner, a blowline, and a press, the method comprising: a) introducing woodchips to the plug flow screw; b) passing the woodchips through the plug flow screw to the cooker; c) adding a soy component having a protein dispersibility index (PDI) less than 50 selected from the group consisting of soy flour, soy meal, soy flake, and mixtures thereof to the cooker; d) passing the woodchips from step c) through the refiner to produce glued refiner wood fibers; e) passing the glued refiner wood fibers from d) through the blowline to produce pressable wood fibers; f) optionally adding a water retardant selected from the group consisting of glycerol, sorbitol, maltitol, and mixtures thereof to the blowline; and g) pressing the pressable wood fibers under heat and pressure to form the fiberboard.

2. The method of claim 1, wherein the method further comprises, adding polyamidoamine- epichlorohydrin (PAE), polymeric methylene diphenyl diisocyanate (PMDI), epoxidized vegetable oils, (vegetable) wax emulsions to the blowline.

3. The method of claim 1, wherein the water retardant selected from the group consisting of glycerol, sorbitol, and mixtures thereof to the blowline.

4. The method of claim 1, wherein the water retardant comprises glycerol.

5. The method of any of claims 1-4, wherein the pressure during step g) is from 20 to 400N / cm2.

6. The method of any of claims 1-5, wherein the temperature during step g) is from 140°C to 260°C.

7. The method of any of claims 1-6, wherein a swell -retardant component is added prior to the refiner.

8. The method of any of claims 1-7, wherein a swell-retardant component is added to the blowline.

9. The method of any of claims 7 and 8, wherein the swell-retardant component comprises a wax.

10. The method of any of claims 1-9, wherein from 5% to 20% dry weight percent soy component based on the dry weight of wood chips introduced in step a) (e.g., from 5 dry weight percent to 15 dry weight percent of soy component) (e.g., 7 dry weight percent to 15 dry weight percent) based on the dry weight of the wood chips added in step a).

11. The method of any of claims 1-10, wherein the soy component has a protein content of from 35 wt% to 65 wt% (for example, from 40 wt% to 60 wt%).

12. The method of any of claims 1-11, wherein the water retardant is selected from the group consisting of glycerol, sorbitol, and mixture thereof, and from 0 to 8 dry weight percent water retardant is added based on the dry weight of wood chips introduced in step a) (e.g., from 0 dry weight percent to 6 dry weight percent of water retardant (e.g., 0 dry weight percent to 4 dry weight percent) based on the dry weight of the wood chips added in step a).

13. The method of any of claims 1-12, wherein an anti -foam agent is added to the blowline.

14. The method of claim 13, wherein the anti-foam agent comprises polypropylene glycol.

15. The method of any of claims 1-14, wherein a surfactant is added to the blowline.

16. The method of claim 15, wherein the surfactant comprises polysorbate 20.

17. The method of any of claims 1-16, wherein a sulfite agent is added to the blowline.

18. The method of claim 17, wherein the sulfite agent selected from the group consisting of sodium sulfite, sodium bisulfite, sodium metabisulfite, and mixtures thereof.

19. The method of any of claims 1-18, wherein a base is added to the blowline.

20. The method of claim 19, wherein the base is selected from the group consisting of sodium hydroxide, magnesium oxide, potassium hydroxide, and mixtures thereof.

21. The method of claim 19, wherein the base comprises sodium hydroxide and from 0.1 to 0.5 weight percent is added based on the dry weight of the wood chips added in step a.

22. The method of claim 2, wherein PAE is added from 0.05 to 0.5 wt%, from 0. 1 to 0.4 wt %, from 0.2 to 0.4 wt% based on the dry wood chips.

23. The method of any of claims 17 and 18, wherein sulfite agent comprises from about 0.1 to 2.0 wt% of the wood chips of step a) (for example from 0.1 to 1.0 wt%, from 0.1 to 0.8 wt%, from 0. 14 to 08 wt% of the wood chips of step a).

24. The method of claim 23, wherein the sulfite agent comprises sodium di-sulfite.

25. The method of any of claims 1-24, wherein a biocide is added to the blowline.

26. The method of claim 25, wherein the biocide comprises from 0.05 to 2.0 wt% of the dry weight of the wood chips of step a) (for example, from 0.1 to 1.0 wt%).

27. The method of claim 9, wherein the wax is in the form of an emulsion and is applied prior to, during or after step a).

28. The method of any of claims 1-27, wherein the glycerol comprises technical grade glycerol.

29. The method of claim 28, wherein the technical grade glycerol comprises at least 95 wt% glycerol, at least 97 wt%, at least 98 wt% or at least 99 wt% glycerol.

30. The method of any of claims 1-28, wherein the glycerol is a crude glycerol mixture comprising 70 wt% to 95 wt% glycerol.

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