Preparation method of waste vinasse-based wood adhesive

Abstract

The invention discloses a preparation method of a waste vinasse-based wood adhesive, and relates to the technical field of biomass waste high-value utilization and adhesives, and the preparation method comprises the following steps: pouring waste vinasse into a sodium periodate aqueous solution, heating and stirring under a dark condition to form oxidized waste vinasse, and then cleaning with deionized water to remove unreacted sodium periodate; the cleaned oxidized waste vinasse is put into a drying oven to be dried, and the waste vinasse-based wood adhesive is obtained; the waste vinasse-based wood adhesive is coated between two wood chips, and the two wood chips are placed in a hot press for hot pressing, so that bonding of the wood chips is achieved. The waste vinasse-based wood adhesive has excellent adhesive performance and solvent resistance, does not contain formaldehyde, greatly reduces the formaldehyde emission, and is beneficial to the environment and human health.

Description

Technical Field

[0001] The invention relates to the technical field of high-value utilization of biomass waste and adhesives, and in particular to a method for preparing a waste dregs-based wood adhesive. Background Art

[0002] The use of wood adhesives is a fundamental aspect of the production of wood composites. Common traditional wood adhesives (such as urea-formaldehyde resins, melamine-urea-formaldehyde resin adhesives, and phenolic resins) have been widely used in industry due to their low price, excellent bonding properties, and high water resistance. However, formaldehyde and other volatile compounds released by traditional adhesives threaten human health and pollute the environment. Therefore, there is an urgent need to develop an environmentally friendly wood adhesive.

[0003] Dried grains (DG) are the residues left after solid-state fermentation and distillation of biomass raw materials such as corn, sorghum, wheat, and barley under the action of complex microbial systems. They are typical by-products of China's traditional fermented food industry. According to industry estimates, China's liquor production will reach about 4.492 million kiloliters in 2023. It is worth noting that only one ton of liquor will produce 3-4 tons of DG. Considering this huge output, efficient processing and utilization of DG remains a key but challenging issue in the industry. The main components of the dried grains are cellulose, lignin, and starch, which can be used to prepare adhesives through chemical modification. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a waste dregs-based wood adhesive. The effective components (cellulose and lignin) in the waste dregs are selectively oxidized in situ by sodium periodate, and the wood is bonded by a hot pressing process. The strong cross-linked network inside the prepared wood adhesive gives it excellent adhesive properties and solvent resistance.

[0005] The object of the present invention is achieved through the following technical scheme: a method for preparing a waste-waste-based wood adhesive, the method comprising the following steps:

[0006] S1. Pour the waste dregs into a sodium periodate aqueous solution, heat and stir in the dark to form oxidized waste dregs, and then wash with deionized water to remove unreacted sodium periodate.

[0007] S2. Put the washed oxidized dregs into an oven for drying to obtain dregs-based wood adhesive.

[0008] S3, applying the waste-wax-based wood adhesive between the two wood chips, and placing them in a hot press for hot pressing to achieve bonding of the wood chips.

[0009] In the step S1, the mass ratio of the waste grains to sodium periodate is 1:2 or 1:1.

[0010] The raw material source of the spent grains is sorghum spent grains or corn spent grains.

[0011] Further, 5-10 g of the waste grains are weighed and poured into the sodium periodate aqueous solution.

[0012] The concentration of sodium periodate in the sodium periodate aqueous solution is 30-45 mg / ml. If the concentration is too high, the oxidation reaction will be too violent, making it difficult to control the reaction process and resulting in poor chemical stability. If the concentration is too low, the kinetic rate of the oxidation reaction will decrease, which may result in prolonged reaction time or even incomplete reaction.

[0013] The time for the waste grains to be oxidized by the sodium periodate aqueous solution is 2-10 hours. If the oxidation time is too short or too long, its adhesive properties will be affected.

[0014] The heating and stirring temperature is 40-50°C. If the temperature is too high, sodium periodate will decompose too quickly, reducing the oxidation efficiency and generating iodate impurities. If the temperature is too low, the reaction rate will be affected.

[0015] The washed oxidized waste is placed in an oven for drying at a temperature of 35° C. Too high a drying temperature may lead to carbonization, while too low a drying temperature may lead to incomplete drying.

[0016] Apply the waste-wax-based wood adhesive between two wood chips and place them in a hot press at 100-110℃ for 0.5-1h with a hot pressing pressure of 2MPa to achieve bonding of the wood chips. Too high a hot pressing temperature or too long a hot pressing time will cause carbonization, while too low a hot pressing temperature or too short a hot pressing time will result in failure to bond.

[0017] The beneficial effects of the present invention are:

[0018] 1. The present invention selectively oxidizes the effective components (cellulose and lignin) in the waste grains in situ with sodium periodate, and then glues the wood by hot pressing. The strong cross-linked network inside the prepared wood adhesive gives it excellent adhesive properties and solvent resistance.

[0019] 2. The oxidation waste of the present invention has an aldehyde content of up to 3.90 mmol / g.

[0020] 3. The best adhesive strength of the waste-waste-based wood adhesive of the present invention is 2.29MPa, and the adhesive energy is 5.21KJ / m 2 .

[0021] 4. After the waste-waste-based wood adhesive of the present invention is soaked in water for 12 hours, the bonding strength can still reach 1.34MPa, and the bonding energy can reach 3.76KJ / m 2 .

[0022] 5. The waste-wax-based wood adhesive of the present invention has excellent solvent resistance (water, salt water, oil, ethanol and other organic solvents, etc.).

[0023] 6. The waste-waste-based wood adhesive of the present invention has excellent stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure after two pieces of wood are bonded using a waste-based wood adhesive;

[0025] Figure 2 The figure on the right shows the adhesive properties of the waste dregs-based wood adhesive, where the figure on the right shows the adhesive strength and adhesive energy of the waste dregs oxidized by sodium periodate aqueous solution at different times;

[0026] Figure 3 The adhesive properties of the waste-based wood adhesive after being immersed in water for different time periods;

[0027] Figure 4 The adhesive properties of waste-based wood adhesive after storage for different time periods;

[0028] Figure 5 The adhesive properties of waste-based wood adhesives after immersion in different solvents include water, dichloromethane, dimethylformamide, tetrahydrofuran, ethanol, oil, and seawater. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0031] In the first embodiment of the present application:

[0032] (1) 5g of DG powder and 10g of sodium periodate NaIO 4Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 2 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0033] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0034] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 100°C and 2MPa for 0.5h. The adhesive strength is 1.50MPa and the adhesive energy is 2.15KJ / m 2 .

[0035] In the second embodiment of the present application:

[0036] (1) 5g of DG powder and 10g of sodium periodate NaIO 4 Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 4 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0037] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0038] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 100°C and 2MPa for 0.5h. The adhesive strength is 1.62MPa and the adhesive energy is 2.46KJ / m 2 .

[0039] In the third embodiment of the present application:

[0040] (1) 5g of DG powder and 10g of sodium periodate NaIO 4 Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 6 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0041] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0042] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 100°C and 2MPa for 0.5h. The adhesive strength is 1.78MPa and the adhesive energy is 2.86KJ / m 2 .

[0043] In the fourth embodiment of the present application:

[0044] (1) 5g of DG powder and 10g of sodium periodate NaIO 4 Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 8 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0045] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0046] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 100°C and 2MPa for 0.5h. The adhesive strength is 1.80MPa and the adhesive energy is 2.95KJ / m 2 .

[0047] In the fifth embodiment of the present application:

[0048] (1) 5g of DG powder and 10g of sodium periodate NaIO 4 Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 10 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0049] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0050] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 100°C and 2MPa for 0.5h. The adhesive strength is 1.81MPa and the adhesive energy is 2.96KJ / m 2 .

[0051] In the sixth embodiment of the present application:

[0052] (1) 5g of DG powder and 5g of sodium periodate NaIO 4 Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 2 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0053] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0054] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 110°C and 2MPa for 1 hour. The adhesive strength is 2.09MPa and the adhesive energy is 6.78KJ / m 2 .

[0055] In the seventh embodiment of the present application:

[0056] (1) 5g of DG powder and 5g of sodium periodate NaIO 4 Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 4 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0057] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0058] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 110°C and 2MPa for 1 hour. The adhesive strength is 2.22MPa and the adhesive energy is 6.28KJ / m 2 .

[0059] In the eighth embodiment of the present application:

[0060] (1) 5g of DG powder and 5g of sodium periodate NaIO 4 Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 6 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0061] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0062] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 110°C and 2MPa for 1 hour. The adhesive strength is 2.27MPa and the adhesive energy is 6.23KJ / m 2 .

[0063] In the ninth embodiment of the present application:

[0064] (1) 5g of DG powder and 5g of sodium periodate NaIO 4 Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 8 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0065] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0066] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 110°C and 2MPa for 1h. The adhesive strength is 2.29MPa and the adhesive energy is 6.25KJ / m 2 .

[0067] In the tenth embodiment of the present application:

[0068] (1) 5g of DG powder and 5g of sodium periodate NaIO 4 Add to 400 ml of deionized water. The mixture is reacted in a dark environment at 50°C for 10 hours. After the reaction is completed, the product is washed at least 3 times with deionized water to remove unreacted sodium periodate and sodium iodide reduction byproducts.

[0069] (2) The washed material was then dried at 35°C to obtain oxidized waste lees and a waste lees-based wood adhesive.

[0070] (3) Apply the waste-wax-based wood adhesive to the surfaces of two pieces of wood and hot-press at 110°C and 2MPa for 1h. The adhesive strength is 2.28MPa and the adhesive energy is 5.21KJ / m 2 .

[0071] The raw material source of the spent grains is sorghum spent grains or corn spent grains, and the concentration of sodium periodate in the sodium periodate aqueous solution is 30-45 mg / ml. In summary, the spent grains-based wood adhesive prepared by the present invention has excellent adhesive properties, as well as excellent stability and solvent resistance.

[0072] The waste dregs-based wood adhesive obtained according to the scheme of this embodiment can be mass-produced because of its wide source of raw materials and simple preparation process.

[0073] The above is only an embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a waste-waste-based wood adhesive, characterized in that: The following steps are involved: S1, pouring the waste into a sodium periodate aqueous solution, heating and stirring in the dark to form an oxidized waste, and then washing with deionized water to remove unreacted sodium periodate; S2, placing the washed oxidized dregs into an oven for drying to obtain a dregs-based wood adhesive; S3, applying the waste-wax-based wood adhesive between the two wood chips, and placing them in a hot press for hot pressing to achieve bonding of the wood chips.

2. The method for preparing a waste-waste-based wood adhesive according to claim 1, characterized in that: The mass ratio of the waste grains to sodium periodate is 1:

2.

3. The method for preparing a waste-waste-based wood adhesive according to claim 1, characterized in that: The mass ratio of the waste grains to sodium periodate is 1:

1.

4. The method for preparing a waste-waste-based wood adhesive according to claim 2 or 3, characterized in that: In the step S1, the raw material of the spent grains is sorghum spent grains or corn spent grains.

5. The method for preparing a waste-waste-based wood adhesive according to claim 4, characterized in that: Weigh 5-10g of the waste grains and pour them into the sodium periodate aqueous solution.

6. The method for preparing a waste-waste-based wood adhesive according to claim 2 or 3, characterized in that: The concentration of sodium periodate in the sodium periodate aqueous solution is 30-45 mg / ml.

7. The method for preparing a waste-waste-based wood adhesive according to claim 2 or 3, characterized in that: The time for the waste grains to be oxidized by the sodium periodate aqueous solution is 2-10 hours.

8. The method for preparing a waste-waste-based wood adhesive according to claim 2 or 3, characterized in that: The heating and stirring temperature is 40-50°C.

9. The method for preparing a waste-waste-based wood adhesive according to claim 2 or 3, characterized in that: The washed oxidized waste was placed in an oven for drying at a temperature of 35°C.

10. The method for preparing a waste-waste-based wood adhesive according to claim 2 or 3, characterized in that: In the step S3, the waste dregs-based wood adhesive is applied between two wood chips, and the two wood chips are placed in a hot press at 100-110° C. for 0.5-1 h, and the hot press pressure is 2 MPa to achieve bonding of the wood chips.

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