GB2524714A

GB2524714A - Distiller's grain (DG) based bio-adhesives: compositions, uses and processes for manufacturing

Info

Publication number: GB2524714A
Application number: GB1401275.1A
Authority: GB
Inventors: Xiaobin Zhao
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-01-27
Filing date: 2014-01-27
Publication date: 2015-10-07
Also published as: GB201401275D0

Abstract

Distiller's Grain (DG) based bio-adhesives consisting of DG biomass, cross linking agents and fillers is disclosed. Optionally, other additives can be included to form aqueous bio-adhesives suitable as substitutes of formaldehyde based wood glue for wood paneling process. There is also provided a process to manufacture such DG bio-adhesives which comprising the steps of : A) blending DG biomass, a cross-linking agent and inorganic fillers to form a blend by mechanical blender; B) micronisation or homogenization of the blend to obtain powdery material and C) mixing the powdery material with additional water, optionally with the addition of other additives such as defoaming agent, thickener, wet-strength agent and another cross linking agent to form DG based bio-adhesives. The DG bio-adhesives can also be used in environmentally friendly construction and packaging industry.

Description

Distillers Grain (DG) based bio-adhesives: Compositions, Uses and Process for Manufacturing

1. Field of Invention

This invention concerns novel water-resistant and versatile adhesive products and glue derived from grain-based ethanol production byproducts including CDS (condensed distiller's solubles), DDG (Distiller's Dried Grain), DDGS (Distiller's Dried Grains and Solubles) and WDG (Wet Distiller's Grain) materials. In this patent, the term Distiller's Grain (DG) is used in general. In particular, the processed DG bio-adhesives according to this invention have strong dry and wet strength and are thus as useful as formaldehyde-free wood adhesives to replace currently used formaldehyde based wood adhesives. The invention further relates to DG-derived glues and adhesive products containing a cross-linked network which can be further processed into powder form to become adhesive gel or aqueous glue.

2. Background Art and Related Disclosures

Due to the inherently finite nature of fossil fuel resources, the world faces the challenge of finding suitable renewable substitutes that can begin to replace petrochemicals both as a source of energy and as a source of materials for plastics, rubbers! fertilizers, and fine chemicals. More recently, biofuels have been endorsed as a key component of national and international strategies to reduce greenhouse gas (GHG) emissions and mitigate potential climate change effects.

Two biofuels, ethanol (ethyl alcohol) and biodiesel from fatty acid methyl esters account for the vast majority of global biofuel production and use today. These biofuels are made primarily from agricultural commodities, such as grain and sugar cane beet molasses, cassava, whey, potato and food or beverage waste for ethanol and vegetable oil for biodiesel.

In 2010, approximately 87 billion litres (23 billion gallons) of ethanol were produced, with the United States, Brazil, and the European Union accounting for 93% of this output (RFA, 2011a), which leaves large quantities of DG byporducts, mainly used for animal feeds.

Two processes are primarily used to make ethanol from grains: dry milling and wet milling. In the dry milling process, the entire grain kernel typically is ground into flour (or "meal") and processed without separation of the various nutritional component of the grain. The flour is slurred with water to form a "mash". Enzymes are added to the mash, which is then processed in a high-temperature cooker, cooled and transferred to fermenters where yeast is added and the conversion of sugar to ethanol begins. After fermentation, the resulting ethanol containing mixture beer" is transferred to distillation columns where the ethanol is separated from the residual "stillage". The stillage is sent through a centrifuge that separates the solids from the liquids. The liquids, or solubles, are then concentrated to a semi-solid state by evaporation, resulting in condensed distiller's solubles (CDS) or "syrup" CDS is sometimes sold direct into the animal feed market, but more often the residual coarse grain solids and the ODS are mixed together and dried to produce distiller's dried grain with solubles (DDGS). In the cases where the CDS is not re-added to the residual grains, the grain solids product is simply called distiller's dried grain (DDG). If the distiller's grain is being fed to livestock in close proximity to the ethanol production facility, the drying step can be avoided and the product is called wet distiller's grain (WDG). Because of various drying and syrup application practices, there are several variants of distiller's grain (one of which is called modified wet distiller's grain), but most product is marketed as DDGS, DDG or WDG.

Some dry-mill ethanol plants in the United States are now removing crude maize oil from the CDS or stillage at the back end of the process, using a centrifuge. The maize oil is typically marketed as an individual feed ingredient or sold as a feedstock for further processing (e.g. for biodiesel production). The co-product resulting from this process is known as "oil extracted" DDGS or "de-oiled" DDGS. These co-products typically have lower fat content than conventional DDGS, but slightly higher concentrations of protein and other nutrients. A very small number of dry-mill plants also have the capacity to fractionate the grain kernel at the front end of the process, resulting in the production of germ, bran, "high-protein DDGS" and other products (RFA, 2011b). In some cases, ethanol producers are considering using the cellulosic portions of the maize bran as a feedstock for cellulosic ethanol. The majority of grain ethanol produced around the world today comes from the dry milling process. In the wet milling process, shelled maize is cleaned to ensure it is free from dust and foreign matter. Next, the maize is soaked in water, called "steepwater", for between 20 and 30 hours. As the maize swells and softens, the steepwater starts to loosen the gluten bonds with the maize, and begins to release the starch. The maize goes on to be milled. The steepwater is concentrated in an evaporator to capture nutrients, which are used for animal feed and fermentation. After steeping, the maize is coarsely milled in cracking mills to separate the germ from the rest of the components (including starch, fibre and gluten). Now in a form of slurry, the maize flows to the germ separators to separate out the maize germ.

The maize germ, which contains about 85% of the maize's oil, is removed from the slurry and washed. It is then dried and sold for further processing to recover the oil. The remaining slurry then enters fine grinding. After the fine grinding, which releases the starch and gluten from the fibre, the slurry flows over fixed concave screens which catch the fiber but allow the starch and gluten to pass through. The starch-gluten suspension is sent to the starch separators. The collected fibre is dried for use in animal feed. The starch-gluten suspension then passes through a centrifuge where the gluten is spun out.

The gluten is dried and used in animal feed. The remaining starch can then be processed in one of three ways: fermented into ethanol, dried for modified maize starch, or processed into maize syrup. Wet milling procedures for wheat and maize are somewhat different. For wheat, the bran and germ are generally removed by dry processing in a flour mill (leaving wheat flour) before steeping in water.

In 2010, an estimated 142.5million tonnes of grain was used globally for ethanol (F.O.

Licht, 2011), representing 6.3% of global grain use on a gross basis. Because roughly one-third of the volume of grain processed for ethanol actually was used to produce animal feed, it is appropriate to suggest that the equivalent of 95 million tonnes of grain were used to produce fuel and the remaining equivalent 47.5million tonnes entered the feed market as co-products. Thus, ethanol production represented 4.2% percent of total global grain use in 201 0/11 on a net basis. The United States was the global leader in grain ethanol production, accounting for 88% of total grain use for ethanol. The European Union accounted for 6% of grain use for ethanol, followed by China (3.4%) and Canada (2.3%). The vast majority of grain processed for ethanol by the United States was maize, though grain sorghum represented a small share (approximately 2%).

Canada's industry primarily used wheat and maize for ethanol, while European producers principally used wheat, but also processed some maize and other coarse grains. Maize also accounted for the majority of grain use for ethanol in China.

There is huge existing market of wood glue for wood panel industry. Organic polymers of either natural or synthetic origin are the major chemical ingredients in all formulations of wood adhesives. Urea-formaldehyde is the most commonly used adhesive, which can release low concentrations of formaldehyde from bonded wood products under certain service conditions. Formaldehyde is a toxic gas that can react with proteins of the body to cause irritation and, in some cases, inflammation of membranes of eyes, nose, and throat. It is a suspected carcinogen, based on laboratory experiments with rats.

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Phenol-formaldehyde adhesives, which are used to manufacture plywood, flakeboard, and fiberglass insulation, also contain formaldehyde. However, formaldehyde is efficiently consumed in the curing reaction, and the highly durable phenol4orrnaldehyde, resorcinol-formaldehyde, and phenol-resorcinol-formaldehyde polymers do not chemically break down in service to release toxic gas. However, it uses the petroleum-based resource and also expensive.

Increasing environmental concerns and strict regulations on emissions of toxic chemicals have forced the wood composites industry to develop environmentally friendly alternative adhesives from abundant renewable substances such as soybean protein, animal, casein, vegetable, and blood. Also, adhesives from lignin, tannin, and carbohydrates have been studied for replacement of synthetic adhesives that are dominatingly used in the manufacture of wood composite products. These adhesives are generally used for non-structural applications, due to their poor water resistance and low strength properties.

Modifications including further purification to obtain high protein contents, increases of the specific surface area of the materials, denaturation of the protein by acid] alkaline and surfactants have been shown to be useful to enhance the wood adhesive strength of soy based glue, or mixed with other synthetic adhesives such as phenol formaldehyde resin which increase the cost for manufacturing.

It would, therefore, be advantageous to provide renewable bio-adhesives which are able to be used as wood adhesives with comparable strength as the synthetic wood adhesives such as formaldehyde based glue.

It is, therefore, a primary objective of the present invention to provide a stable adhesive which is relatively inexpensive and versatile for use in a number of applications..

It is, therefore, a further object of the present invention to provide a stable aqueous adhesive comprising DG-material derived from ethanol production, and that are safe, water-resistant for wood application. The DG materials include DDGS, ODS, DDG and WDG from byproducts of ethanol production plant.

It is a further object of the present invention to prepare DG based adhesive products that are produced by mixing dry DG materials with additives and further milled into fine powder for greater adhesive strength properties to broaden their suitability for adhesive applications, easy in storage for longer shelf-life and transportation.

It is yet a further objective of the invention to prepare DG based adhesive products that are produced by mixing dewatered DG materials, e.g. WDG and CDS (water content less than 70%) with additives and homogenised into aqueous bio-adhesives.

It is yet a further object of the invention to prepare an adhesive that consists essentially of byproducts of after ethanol distillation during ethanol biofuel process.

It is yet another object of the invention to prepare adhesive products that comprise naturally DG materials in dry form (e.g. DDGS and DDG) that are blended with a crosslinking agent to form a crosslinked network to enhance the water resistance of the adhesives.

It is further another object of the invention to mill the above mixture to greater than 8Omeshes for formulation into aqueous adhesives.

It is yet another objective of the invention to prepare adhesive products that comprise above aqueous adhesives and a crosslinking agent and/or wet-strengthen agent for water-resistant wood industry application.

DETAILED DESCRIPTION OF THE INVENTION

The current invention concerns novel bio-adhesives derived from DO materials.

According to a first aspect of the invention there is provided DO based bio-adhesives consisting of DO mass, crosslinking agents and inorganic fillers, optionally other additives for making aqueous DO bio-adhesives.

According to a second aspect of the invention there is provided a process for manufacturing such DO based bio-adhesives, the process comprising the steps of: a. Combining DG material obtained directly from ethanol production plant, such as DDGS DDG, CDS and WDG with defined dryness and suitable protein content, a cross-linking agent, and fillers to form a blend using a mechanical mixer or blender, Whereas in step a: the DG material has the water content less than 70%; preferably less than 40%; most preferably less than 20%; the crosslinking agent is selected from a organic polymeric material with crosslinkable groups such as poly-isocyanate, epoxy resin, or an inorganic material such as silicates, borates or mixture of polymeric crosslinker and the inorganic substance; the fillers are calcium materials such as calcium oxide, calcium hydroxide, calcium chloride, calcium carbonate calcium sulfate, preferably calcium oxide, calcium sulfate which can dewater during the blending process. The DG material in the blend has the content between 50-89%, crosslinking agent has 1.0-20%, and fillers are 10-30%.

b. Milling the blend via a micronisation milling machine or any other chosen mechanical wet or dry milling machine to produce fine powdery material with particle size between 80-600meshes., preferably, between 100-500meshes, most preferably 200-300meshes.

c. Mixing the powdery material with additional water, optionally with addition of a defoamer or an anti-foaming agent, a thickener and optionally with a crosslinking agent or wet-strength agent, wherein defoamer is selected from food grade defomier used in milk, protein process industry, such as mineral oil, vegetable oil or white oil based deforming agent; the thickener selected are food grade water soluble natural polymer such as cellulose derivatives e.g. HPMC, CMC, proteins such as gelatin, alginate, chitosan; and water soluble polymers such as Polyvinyl alcohol (PVA) , sodium polyacrylic acid (PAA) or it's copolymer. The wet strength agent is poyamideamine-epichlorohydrin (RAE), the crosshnking agent is a poymedc isocyanate or polymeric isocyanate with the isocyanate group blocked to obtain DG aqueous bio-adhesives with soUid content between 20-60%, preferably 20-50%, most preferably 20-40%.

According to the invention there is provided a process for manufacturing DC based bio-adhesives, the process comprising the steps of: a. combining DC material, a cross-linking agent and inorganic fillers to form a blend by mechanical blender; b. Micronising or mechanical milling the blend to obtain powdery material and c. Mixing the powdery material with additional water, or optionally with the addition of other additives such as defoaming agent, thickener, wet strength agent and a crosslinking agent to form DC based bio-adhesives.

DC biomass contains lipids, proteins, and carbohydrates that mainly is used for animal feed. Compared to soy meal, the protein content is ranged from 20-40% depending on the process of the byproduct. Typically for DDGS, the protein content is between 20- 30%. Due to the nature of the origin, the cost of DG is much lower than that of soy meal.

For example, the price of DDGS is about 1/2 -1/3 of the price of soy flower.

Surprisingly it was found that DG containing 20-30% protein (dry mass) without further expensive refining to increase the protein content can be used for the current process to produce bio-adhesives. The DG biomass is the by-products directly from ethanol production plant, which are readily available as animal feed material, including CGS, DDG, DDGS and WDG. The quantity required for the formulation can be adjusted according to the protein content and the solid content of the mass.

The crosslinking agent used in current invention is polymeric isocyanate which is used to produce polyurethane. The polyisocyanate functional groups used in current invention include PMDI, PHDI, Polyurethane pre-polymer, blocked polyisocyanates such as polyisocyanates with phenol, s-caprolactam blocked. A blocked polyisocyanate can be defined as an isocyanate reaction product which is stable at room temperature but dissociates to regenerate isocyanate functionality under the influence of heat around 100-250°C. Blocked polyisocyanates based on aromatic polyisocyanates dissociate at lower temperatures than those based on aliphatic ones. The dissociation temperatures of blocked polyisocyanates based on commercially utilized blocking agents decrease in this order: alcohols> c -caprolactam>phenols>methyl ethyl ketoxime>active methylene compounds.

Other crosslinking agent can be used in current invention include epoxy-resins. Epoxy resins, also known as polyepoxides are a class of reactive prepolymers and polymers which contain epoxide groups. Epoxy resins are polymeric or semi-polymeric materials and An important criterion for epoxy resins is the epoxide content. This is commonly expressed as the epoxide number, which is the number of epoxide equivalents in 1 kg of resin (Eq/kg), or as the equivalent weight, which is the weight in grams of resin containing 1 mole equivalent of epoxide (g/mol). One measure may be simply converted to another: Equivalent weight (g/mol) = 1000/ epoxide number (Eq/kg) The epoxy resin can be used in current invention include Bisphenol A epoxy resin, Bisphenol F epoxy resin, Aliphatic epoxy resin and Glycidylamine epoxy resin.

The content of the polymeric crosslinking agent mixed with DG materials is between 1.0-20%.

Other crosslinking agents can be used include inorganic materials such as silicates and borates which can be used separately or mixed with above polymeric crosslinking agent.

The total content is in the range of 1.0-20%, preferably in the range of 1-10%, most preferably in the range of 5-10%.

The fillers used for current application are calcium based inorganic materials. They can be used to adjust the water content of the DG materials and the reheological properties of the final bio-adhesives. They can also be useful to help the subsequent dry milling process. The more calcium materials are incorporated, the more dry blend can be obtained. The typical content of the calcium materials such as single calcium oxide, calcium chloride calcium carbonate and calcium sulfate or their mixtures is in the range of 10-30%. The optimised composition for ease of dry milling with different machines can be adjusted by changing the ratio of DG mass and the fillers.

After the blending with an industrial mechanical blender, the mixture needs to be stored overnight (>8hrs) before milling. The fine powder will give a homogenized mixture in order to swell in water to form bio-adhesives for easy to spray or spread for applications.

The milling process can be performed by readily available micronisation equipment, or mechanical milling machines. The particle size obtained is controlled at 80-600meshes, preferably at 100-500meshes, most preferably at 200-300meshes. When WDG is used, the milling can be achieved by a homogenization process, which can directly lead to final aqueous bio-adhesives.

The DG bio-adhesives can be formulated by adding the above milled powder into premeasured water in a batch vessel with a mixer or pumping into a mechanical static mixer with a calculated amount of water, or into a batch homogeniser or online homogeniser for continuous formulation of the aqueous bio-adhesives.

The solid content of the formed bio-adhesives is between 20-50% and preferably between 20-40%.

Optionally, in the formulation of the aqueous bio-adhesives, some additives can be added for easy manufacturing, optimized viscosity and enhanced wet strength for applications.

The additives include defoamer or an anti-foaming agent, a thickener and optionally with a crosslinking agent or wet-strength agent, wherein the defoamer is selected from food grade deformer used in the milk or protein process industry, such as mineral oil, vegetable oil or white oil based deforming agent; the thickener selected are food grade water soluble natural polymer such as cellulose derivatives e.g. HFMC, CMC, proteins such as gelatin, alginate, chitosan etc; or water soluble hydrogel such as PVA, FAA and FAA copolymer, the wet strength agent is poyamdeamine-*epichlorohydrin (PAL), the crosslinkng agent is a pdymeric socyanate or a polymeric isocyanate with the socyanate group b'ocked. The percentage of the additives considered to be added is in the range of 0.015%, preferab'y in the range of 0.1-5%, most preferab'y in the range of 0.5-5%.

The main application of current invention of DO bio-adhesives is in the field of production of wood based panels to replace formaldehyde based wood adhesives. The wood based panels include plywood, fibreboard and particle board.

The DG bio-adhesives can also be used for making paper-based board such as paper packaging board, cardboard, carton packaging material for recyclable food packaging, gift packaging and medical packaging. Other applications include adhesives for furniture used in hospital and school. The bio-adhesives can also be used to make fibreboard based on non-wood materials such as straw. The straw based fibreboard can be used as packaging materials for food. The DG bio-adheisives can also be used in marine board whereas the highly water-resistant wood board is required. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments, various applications of the described modes of carrying out the invention which are obvious to those skilled in the art are intended to be covered by the present invention.

The invention now will be further exemplified.

Example I

Preparation of DDGS based bio-adhesive: DDGS, water content 10%, protein content 26%, lipid content 5%, was from USA. In a mechanical blender (250KG volume capacity), 50kg of the DDGS, 10kg of calcium oxide powder (200meshes) and 10kg of sodium silicate was added and mixed for 3omins and stored for 4hours. To the mixture, 2kg of PMDI was slowly added during mixing within 2Omins and blended for further 3omins to obtain a well mixed blend. The blend was sealed and stored overnight for lOhours, and then transferred to an Air-Jet milling machine to obtain fine powder with particle size around 300 meshes. In a 500L high-shear mixing vessel for producing coating material, IOOL water was added, and then 50kg of above milled powder was added and mixed for 60mins. 1Kg PVA powder (1788) was added and mixed for another 6omins. lOOg of defoaming agent was added to obtain the DDGS bio-adhesives ready for plywood process. The solid content is about 33%.

Application of DDGS bio-adhesives for plywood: pieces of poplar veneers were cut into size at 36cm X 36cm. The above algal bio-adhesive was brushed onto one side of the first piece, one side of the last piece and the two sides of the rest of 3 pieces. Amount of bio-adhesives on each veneer was controlled with a balance. 5 pieces of poplar veneers were cross-staged. Assembled wood specimens were pressed at 3 MPa and 120°C for 10 mm or 150 00 for 5 mm with a hot press. The wood assemblies were conditioned at 23°C and 50% RH for 48 h and then cut into five pieces with overall dimensions of 80 x 20 mm and glued dimensions of 20x20 mm.

The cut wood specimens were conditioned for 4 additional days at the same conditions before testing. Shear strength testing was performed using an Instron (Model 4465; Canton, MA, USA) at a crosshead speed of I.6mm/mm according to ASTM Standard Method D906 -98(2011). Shear strength, including dry strength and wet strength, were performed following ASTM Standard Methods (ASTM D906-98 2011) at maximum load was recorded. Values reported are the average of five specimen measurements.

Water resistance test: Specimen was boiled at 100°C for 2hours. The specimen is removed from water and visually inspected for evidence of dismemberment.

Comparison of Urea-Formaldehyde (UF) glue and Phenol-Formaldehyde (PF) glue to make plywood: Commercially UF and PF for pressing plywood were carried out as the method shown in Example 1.

Example 2:

Preparation of DDGS based bio-adhesive: DDGS, water content 10%, protein content 26%, lipid content 5%, was from USA. In a mechanical blender (250 KG volume capacity), 50 kg of the DDGS, 10 kg of calcium oxide powder (200 meshes) and 10 kg of sodium silicate was added and mixed for 3Omins and stored for 4 hours. To the mixture, 2 kg of PMDI was slowly added during mixing within 20 mins and blended for further 30 mins to obtain a well mixed blend. The blend was sealed and stored overnight for 10 hours, and then transferred to an Air-Jet milling machine to obtain fine powder with particle size around 300 meshes. In a 500L high-shear mixing vessel for producing coating material, 150L water was added, and then 50kg of above milled powder was added and mixed for 3omins. To the mixture, 12.5kg of PAF and 2.5kg of PMDI was added and mixed for 6omins. bOg of defoaming agent was added to obtain the algal bio-adhesives ready for plywood process. The solid content is about 30%.

The plywood using above DDGS bio-adhesive was produced according to the same

method as example 1.

Example 3

Preparation of DDGS based bio-adhesive: DDGS, water content 10%, protein content 26%, lipid content 5%, was from USA. In a mechanical blender (250KG volume capacity), 50kg of the DDGS, 10kg of calcium oxide powder (200meshes) and 10kg of sodium silicate was added and mixed for 3omins and stored for 4hours. To the mixture, 2kg of PMDI was slowly added during mixing within 2Omins and blended for further 3omins to obtain a well mixed blend. The blend was sealed and stored overnight for lOhours, and then transferred to an Air-Jet milling machine to obtain fine powder with particle size around 300 meshes. In a 500L high-shear mixing vessel for producing coating material, 100L water was added, and then 50kg of above milled powder was added and mixed for 60 mins. To the mixture, 5.0kg of PMDI was added and mixed for 6omins. bOg of defoaming agent was added to obtain the algal bio-adhesives ready for plywood process. The solid content is about 35%.

The plywood using above DDGS bio-adhesive was produced according to the same

method as example 1.

Example 4 Preparation of CDS based bio-adhesive: CDS was obtained commercially from ethanol production manufacturer. The water content is about 20%, protein content 30%. To a 100L blender, 10kg of the CDS, 2kg of calcium oxide powder (200meshes) and 1kg of sodium silicate was added and mixed for 3omins. To the mixture, 1kg of PMDI was slowly added during mixing within 2omins and blended for further 3omins to obtain a well mixed blend. The blend was sealed and stored overnight for lOhours, and then transferred to an Air-Jet milling machine to obtain fine powder with particle size around 300 meshes. In a 100L high-shear mixing vessel for producing coating material, 40L water was added, and then 10kg of above milled powder was added and mixed for 3omins. To the mixture, 1.0kg of PMDI was added and mixed for 6omins. bOg of defoaming agent was added to obtain the algal bio-adhesives ready for plywood process. The solid content is about 20%.

The plywood using above WDG bio-adhesive was produced according to the same

method as example 1.

Example 5 Preparation of WDG based bio-adhesive: WOG was obtained commercially from ethanol production manufacturer. The water content is about 70%, protein content 10%. In a 100L high-shear homogenizer for producing coating material, 40L WDG was added, and to the mixture, 2 Kg sodium silicate, 1Kg PVA(1788) and 1.0kg of PMDI was added one by one and homogenised for 6omins. bOg of defoaming agent was added to obtain the WDG bio-adhesives ready for plywood process. The solid content is about 28%.

The plywood using above WDG bio-adhesive was produced according to the same

method as example 1.

Example 6

Application of DG bio-adhesives for preparation of particle board DG bio-adhesive produced in example 2 was used to prepare particle board. 150g of DG bio-adhesive was added slowly to 600g of pine wood particles having a moisture content of approximately 5% and mixed with a mechanical mixer. A 9-inch x 9inch x 9 inch wood forming box was centered on a 12 inch x 12 inch x 0.1 inch stainless steel plate, which was covered with aluminum foil. The wood-adhesive mixture is slowly added into the forming box to achieve a uniform density of particles coated with bio-adhesive. The mixture was compressed by hand with a plywood board and the wood forming box was carefully removed so that the particle board matte would not be disturbed. Then, the plywood board was removed, a piece of aluminum foil was placed on the matte, and another stainless steel plate was placed on top of the matte. The particle board matte was then pressed to a thickness of % inch using the following conditions: l2Opsi for lOminutes at a press platen temperature of 170°C. The particle board was trimmed to 5inches X 5 inches to check the water resistant property.

Example 7

Application of DO bio-adhesives for preparation of fiber board DC bio-adhesive produced in example 3 was used to prepare fiber board. 200g of DC bio-adhesive was sprayed slowly to 800g of pine wood fiber having a moisture content of approximately 5% while mixing with a mechanical mixer. A 9-inch x 9inch x 9 inch wood forming box was centered on a 12 inch x 12 inch x 0.1 inch stainless steel plate] which was covered with aluminum foil. The wood-adhesive mixture is slowly added into the forming box to achieve a uniform density of fibers coated with bio-adhesive. The mixture was compressed by hand with a plywood board and the wood forming box was carefully removed so that the fiber board matte would not be disturbed. Then, the plywood board was removed, a piece of aluminum foil was placed on the matte, and another stainless steel plate was placed on top of the matte. The fiber board matte was then pressed to a thickness of % inch using the following conditions: l2Opsi for 10 minutes at a press platen temperature of 170°C. The fiber board was trimmed to Sinches X 5 inches to check the water resistant property.

Test results of plywood produced from DC blo-adhesives in example 1-7 Plywood Dry strength (MPa) Wet strength Water resistance (MPa) test (boiling water for two hours) Example 1 1.8 0.8 Intact Example2 3.0 1.8 Intact Example3 2.5 1.3 Intact Example4 2.5 1.2 Intact Example 5 3.0 1.5 Intact

Example 6 / / Intact

Example 7 / / Intact

Formaldehyde-Urea 2.5 / Dismemberment resin Phenol -Urea resin 3.4 1.8 intact

Claims

Claims: 1. DG bio-adhesives consist of DG mass, crosslinking agents and inorganic fillers, optionally other additives for making aqueous DG bio-adhesives.
2. The algae bio-adhesives in claim 1, wherein the DG sources are from ethanol production byproducts to make biofuel.
3. The DG bio-adhesives in claim 1, wherein the DG are DDGS, DGS, CDS, WDG or their mixture.
4. The DG bio-adhesives in claim 1, wherein the DG mass has the water content less than 70%, preferably less than 40%, most preferably less than 20%.
5. The DG bio-adhesives in claim 1, wherein the DG mass is from the WDG without further drying during the process.
6. The DG bio-adhesives in claim 1, wherein the crosslinking agents are synthetic polymeric crosslinking agents and in-organic materials or mixture of them. The synthetic polymeric crosslinking agents are polyisocyanates, polyisocyanates with blocked isocyanate groups and epoxy resins. The inorganic materials are silicates and borates.
7. The DC bio-adhesives in claim 1, wherein the fillers are calcium minerals including calcium oxide, calcium sulfate, calcium carbonate and calcium hydroxide.
8. The DC bio-adhesives in claim 1, wherein the additives include defoaming agent, wet strength agent, thickeners and crosslinking agent.
9. A process to prepare DC bio-adhesives in claim I comprising the steps of: a. Combining DC mass, a cross-linking agent, and fillers to form a blend using a mechanical mixer or blender, b. Milling the blend via a micronisation milling machine or any other chosen wet or dry mechanical milling machine to produce powdery material with particle size between 80-600 meshes, preferably, between 100-500 meshes, most preferably 200-300 meshes.c. Mixing the powdery material with water, optionally with addition of other additives.
10. As claimed in claim 9 in step a, wherein the blend consists 50-89% of the DC material, 1.0-20% of crosslinking agent and 10-30% of fillers.
11.According to claim 9 in step c, the percentage of the each additive to form aqueous bio-adhesives is between 0.01-5%, preferably 0.1-5%.
12. As claimed in claim 9, wherein the defoamer is food grade defoaming agent, such as mineral oil, vegetable oil or white oil based deforming agent.
13.As claimed in claim 9 in step c, wherein, the thickener is water soluble synthetic or natural polymer such as PVA, Polyacrylic acid (PAA) and PAA copolymer, cellulose derivatives, proteins, alginate and chitosan.
14.As claimed in claim 9 in step c, wherein, the wet strength agent is polyamideamine-epichiorohydrin (PAE).
15.As claimed in claim 9 in step c, wherein the crosslinking agent is a polymeric isocyanate such as PMDI, PHDI, and polymeric isocyanate with the isocyanate group blocked.
16.As claimed in claim 9 in step c, the DG aqueous bio-adhesives have the solid content between 20-60%, preferably 20-50%, most preferably 20-40%.
17.DG bio-adhesives as claimed in claim I for use in water-resistant wood panel process as substitute of formaldehyde based wood adhesives.
18.DG bio-adhesives as claimed in claim 1 for use in water--resistant glue for paper packaging industry.
19. DG bio-adhesives as claimed in claim I for use in hospital, school building board decoration, assembling and construction.