CN114686121B

CN114686121B - Biomass adhesive and preparation method and application thereof

Info

Publication number: CN114686121B
Application number: CN202011600076.XA
Authority: CN
Inventors: 施晓旦; 徐丽; 金霞朝
Original assignee: Shanghai Changfa New Materials Co Ltd
Current assignee: Shanghai Changfa New Materials Co Ltd
Filing date: 2020-12-29
Publication date: 2024-06-28
Anticipated expiration: 2040-12-29

Abstract

The invention discloses a biomass adhesive and a preparation method and application thereof. The preparation method of the biomass adhesive comprises the following steps: (1) The lignin is subjected to an oxidative ammonolysis reaction to prepare a mixed material A; (2) In a solvent, the mixture A, starch, an initiator and a dispersing agent react, and then are mixed with polyvinyl alcohol and aged to prepare a mixture B; (3) The mixed material C reacts with the catalyst for the first time, and then reacts with the coupling agent and the amide compound for the second time; wherein the mixture C is a mixture of the mixture B, phenol, aldehyde and alkaline compound. The formaldehyde release amount of the biomass adhesive prepared by the invention is less than or equal to 0.05mg/L, thus the environment-friendly adhesive with low formaldehyde or no formaldehyde release is prepared, and the environment and personnel safety are protected; low cost, good bonding strength and excellent application performance.

Description

Biomass adhesive and preparation method and application thereof

Technical Field

The invention relates to a biomass adhesive and a preparation method and application thereof.

Background

At present, the artificial board industry is vigorously developed, so that the demand of adhesives for artificial boards is increased. Phenolic glue has the advantages of high bonding strength, good durability, weather resistance, water resistance, strong ageing resistance and the like, and is widely applied to the artificial board industry, but has the defects of high formaldehyde release, high cost, high brittleness and the like. To ameliorate these deficiencies of phenolic adhesives, researchers have been looking for certain renewable raw material modified phenolic resins. Industrial lignin is a natural high molecular polymer with wide sources, low price and aromatic structure. At present, the phenolic resin is generally modified by methylolation, demethylation, phenolization and the like of lignin, so that the cost is reduced, the defects of high brittleness and the like are overcome, and meanwhile, the formaldehyde release amount is reduced, but the formaldehyde release amount is still more than or equal to 0.1 percent. For example, chinese patent application CN108003822a is a phenolic adhesive prepared from methylolated modified lignin, and although this method reduces the cost, the formaldehyde release is still 0.06-0.14 mg/L, and on average 0.1mg/L, and although the glue strength is standard, it is still in a low standard state.

Therefore, there is a need in the art to develop an environment-friendly adhesive with low formaldehyde emission and good bonding strength.

Disclosure of Invention

The invention aims to overcome the defects of high formaldehyde release, high cost, unsatisfactory bonding strength and the like of adhesives in the prior art, and provides a biomass adhesive and a preparation method and application thereof. The formaldehyde release amount of the biomass adhesive prepared by the invention is less than or equal to 0.05mg/L, thus the environment-friendly adhesive with low formaldehyde or no formaldehyde release is prepared, and the environment and personnel safety are protected; low cost, good bonding strength and excellent application performance.

The invention adopts the following technical scheme to solve the technical problems:

the invention provides a preparation method of a biomass adhesive, which comprises the following steps:

(1) The lignin is subjected to an oxidative ammonolysis reaction to prepare a mixed material A;

(2) In a solvent, the mixed material A, starch, an initiator and a dispersing agent react, and then are mixed with polyvinyl alcohol and aged to prepare a mixed material B;

(3) The mixed material C reacts with the catalyst for the first time, and then reacts with the coupling agent and the amide compound for the second time; wherein the mixture C is a mixture of the mixture B, phenol, aldehyde and alkaline compound.

In step (1), the lignin preparation method may be conventional in the art, and preferably comprises the following steps: and (3) preserving heat of the papermaking black liquor, and adjusting the pH value of the system to 3-4.

The papermaking black liquor can be waste water generated in an alkaline pulping process commonly referred to in the papermaking field, for example, papermaking black liquor generated in a papermaking process by Shandong solar control clusters.

Wherein the solids content of the black liquor may be conventional in the art, and may generally be from 15% to 20%, preferably from 18% to 20%. In the invention, the solid content generally refers to the mass percentage of dry materials prepared by removing solvent from the papermaking black liquor to the papermaking black liquor.

Wherein, the papermaking black liquor can be the rest materials except sulfate pulp in the sulfate pulp preparation process, and is generally prepared by the following steps: steaming wood, sodium hydroxide water solution with concentration of 0.5-1.5 mol/L and sodium sulfide water solution with concentration of 0.1-0.3 mol/L, spraying, recovering steam, and washing to obtain sulfate pulp; the remainder of the material except the sulfate pulp is the black liquor.

Wherein the temperature of the incubation may be a temperature conventional in the art for such operations, preferably 50-60 ℃.

The time for the heat preservation can be a time which is conventional in the art for such operations, preferably 1 to 3 hours, more preferably 2 to 3 hours.

The conditions and methods for adjusting the pH of the system to 3-4 may be conventional in the art, and generally may be the addition of an acidic pH adjustor. The acidic pH adjustor can be an acidity adjustor conventionally used in the art with a pH of less than 7, and can be generally one or more of sulfuric acid aqueous solution, hydrochloric acid and acetic acid aqueous solution, preferably sulfuric acid aqueous solution. The concentration of the acidic pH adjustor can be conventional in the art and can generally range from 30wt% to 60wt%.

Wherein, preferably, the pH value of the system is adjusted to 3.5-3.7.

Wherein, the operation of adjusting the pH value of the system to 3-4 can further comprise the operation of filtering and collecting filter cakes and/or washing. The conditions and methods of washing may be conventional in the art, and generally may be such that the eluate is neutral. The wash solution used in the wash process may be conventional in the art and may generally be water and/or ethanol, preferably water.

In step (1), the oxidative ammonolysis reaction may be a process conventionally considered by those skilled in the art as covalent reaction of carbonyl and carboxyl groups in the lignin with ammonia, and preferably includes the following steps: and (3) carrying out oxidative ammonolysis reaction on the lignin, the amination agent, the oxidant and the N, N-dimethylformamide, filtering, and collecting a filter cake to obtain a mixed material A.

Wherein the amination agent can be a reagent which is used in the field and can enable the lignin and the N, N-dimethylformamide to generate amine compounds, and can be one or more of ammonia, liquid ammonia, urea and ammonium salt, preferably ammonia. The ammonium salt is preferably ammonium bicarbonate. The ammonia may be added as ammonia water as is conventional in the art, and the concentration of the ammonia water may be conventional in the art, preferably 25wt% to 30wt%. The percentage is the percentage of the mass of ammonia in the ammonia water to the total mass of the ammonia water.

Wherein the oxidizing agent may be an oxidizing agent conventionally used in the art, and may be generally one or more of peroxide, oxygen, hypochlorous acid and hypochlorite, preferably peroxide. The peroxide is preferably hydrogen peroxide. The hypochlorite is preferably sodium hypochlorite.

When the oxidizing agent is the hydrogen peroxide, the hydrogen peroxide may be added as an aqueous hydrogen peroxide solution as is conventional in the art. Wherein the mass percent of the hydrogen peroxide in the hydrogen peroxide aqueous solution can be conventional in the art, and is preferably 20-30%.

Wherein the mass ratio of the lignin to the amination agent can be conventional in the art, preferably 1: (0.5 to 1.5), more preferably 1:0.9.

Wherein the mass ratio of the lignin to the oxidant may be conventional in the art, preferably (6-17): 1, more preferably (10 to 13.3): 1.

Wherein the mass ratio of the lignin to the N, N-dimethylformamide may be conventional in the art, preferably 1: (1 to 4), more preferably 1: (1.2 to 1.7), more preferably 1: (1.2-1.3).

In step (1), the temperature of the oxidative ammonolysis reaction may be a temperature conventional in the art for such reactions, preferably 40 to 80 ℃, more preferably 50 to 80 ℃.

In step (1), the time for the oxidative ammonolysis reaction may be a time conventional in the art for such a reaction, and is preferably 30 to 50 minutes.

In step (2), the mixture a may further comprise a drying operation before use.

Wherein the drying conditions and methods may be conventional in the art and may generally be carried out in an oven.

Wherein the drying temperature may be a temperature conventional in such operations in the art, preferably 80-100 ℃.

The drying time may be a time conventional in this type of operation in the art, and is preferably 3 to 5 hours, more preferably 4 to 5 hours.

In step (2), the initiator may be a reagent conventionally used in the art for initiating the grafting reaction of the material a, the starch and the polyvinyl alcohol, preferably an inorganic peroxide initiator and/or an azo initiator, more preferably an inorganic peroxide initiator. The inorganic peroxide initiator is preferably ammonium persulfate and/or potassium persulfate, more preferably ammonium persulfate. The azo-based initiator is preferably azobisisobutyronitrile.

In the step (2), the dispersing agent may be a dispersing agent conventionally used in the adhesive field, preferably an anionic surfactant, more preferably one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and sodium hexadecyl sulfonate, and still more preferably sodium dodecyl sulfate.

In step (2), the solvent may be a solvent which is known in the art to be a complete solvent for all the reaction materials, and may be generally an aqueous solution of N, N-dimethylformamide. Wherein the mass percentage of the N, N-dimethylformamide in the N, N-dimethylformamide aqueous solution can be conventional in the art, and is preferably 4-8%, more preferably 5-8%.

In step (2), the polyvinyl alcohol may have a number average molecular weight as conventional in the art, preferably 18 to 20 tens of thousands.

In step (2), the mass ratio of the dry material of the mixture a to the starch may be conventional in the art, preferably 1: (0.125 to 0.5), more preferably 1: (0.2 to 0.35), for example, 1:0.25. in the present invention, the dry material of the mixture a may be the remaining material of the mixture a after drying, which is conventionally considered by those skilled in the art.

In step (2), the mass ratio of the dry mass of the mixture A to the initiator may be conventional in the art, preferably 1: (0.12 to 0.7), more preferably 1: (0.4-0.5).

In step (2), the mass ratio of the dry material of the mixture a to the dispersant may be conventional in the art, preferably 1: (0.0001 to 0.005), more preferably 1: (0.0005 to 0.001).

In step (2), the mass ratio of the dry material of the mixture a to the polyvinyl alcohol may be conventional in the art, preferably 1: (0.02 to 0.1), more preferably 1: (0.031 to 0.079), more preferably 1: (0.042-0.079).

In step (2), the temperature of the reaction may be a temperature conventional in the art for such reactions, preferably 50 to 80 ℃.

In step (2), the reaction time may be a time conventional in the art for such reactions, preferably 1 to 3 hours, more preferably 2 to 3 hours.

In step (2), the conditions and methods of aging may be conventional in the art and may generally be static.

In the step (2), the aging time can be the conventional time for the operation in the field, and the reaction between the material prepared after the reaction in the system and the polyvinyl alcohol can be generally completed, preferably 5-8 h.

In step (3), the catalyst may be a catalyst conventionally used in the art for catalyzing a crosslinking reaction, preferably a metal oxide catalyst, more preferably one or more of zinc oxide, titanium oxide, tin oxide and alpha-iron oxide, and still more preferably zinc oxide.

In step (3), the amide compound may be an amide compound which is conventionally used in the art and can undergo a crosslinking reaction with the phenol and the aldehyde, preferably one or more of acrylamide, polyacrylamide and carbonamide, more preferably acrylamide.

In the step (3), the coupling agent may be a coupling agent conventionally used in the adhesive field, preferably one or more of a silane coupling agent, a polyisocyanate coupling agent and a phthalate coupling agent, more preferably a silane coupling agent.

Wherein the silane coupling agent is preferably one or more of vinyltriethoxysilane, vinyltrimethoxysilane and gamma-methacryloxytrimethoxysilane, more preferably vinyltrimethoxysilane.

In the step (3), the phenol may be phenol conventionally used in the adhesive field, preferably one or more of phenol, meta-alkyl-substituted phenol and para-alkyl-substituted phenol, wherein the alkyl groups in the meta-alkyl-substituted phenol and the para-alkyl-substituted phenol are C ₁～C₄ alkyl groups; the phenol is more preferably phenol. The meta alkyl substituted phenol is preferably meta cresol and/or cardanol. The para-alkyl substituted phenol is preferably 4-t-butylcatechol and/or 4-t-butylphenol, more preferably 4-t-butylphenol.

In the step (3), the aldehyde may be an aldehyde conventionally used in the adhesive field, preferably formaldehyde and/or an aldehyde compound having a double bond in the molecular formula, more preferably formaldehyde. The aldehyde compound having a double bond in the formula is preferably one or more of citral, cinnamaldehyde and citral, more preferably citral.

In step (3), the basic compound may be a basic compound conventionally used in the art for catalytic condensation reaction, preferably one or more of alkali metal hydroxide, alkali metal carbonate compound and alkali metal sulfite compound. The alkali metal hydroxide is preferably one or more of barium hydroxide, sodium hydroxide and calcium hydroxide, more preferably sodium hydroxide. The alkali metal carbonate compound is preferably sodium carbonate and/or sodium bicarbonate. The alkali metal sulphite compound is preferably sodium sulphite.

In step (3), the preparation method of the mixture C may be conventional in the art, and generally comprises the following steps: and uniformly mixing the mixed material B, the phenol, the aldehyde and the alkaline compound. Wherein the mixing time may be conventional in the art and may generally be 20 to 30 minutes.

In step (3), the mass ratio of the mixture B to the phenol may be conventional in the art, preferably 1: (0.3 to 0.7), more preferably 1: (0.4 to 0.52), for example, 1:0.51.

In step (3), the mass ratio of the mixture B to the aldehyde may be conventional in the art, preferably 1: (0.1 to 0.3), more preferably 1: (0.16-0.27).

In step (3), the mass ratio of the mixture B to the basic compound may be conventional in the art, preferably 1: (0.1 to 0.27), more preferably 1: (0.12-0.15).

In step (3), the mass ratio of the mixture C to the catalyst may be conventional in the art, preferably 1: (0.1 to 0.35), more preferably 1: (0.15 to 0.2), for example, 1:0.17.

In step (3), the mass ratio of the mixture C to the coupling agent may be conventional in the art, preferably 1: (0.03 to 0.2), more preferably 1: (0.03 to 0.06), for example, 1:0.05.

In the step (3), the mass ratio of the mixture C to the amide compound may be conventional in the art, and preferably is 1: (0.08 to 0.3), more preferably 1: (0.09-0.1).

In step (3), the temperature of the first reaction may be a temperature conventional in the art for such reactions, preferably 70 to 90 ℃, more preferably 70 to 80 ℃.

In step (3), the time for the first reaction may be a time conventional in the art for such reactions, preferably 1 to 3 hours, more preferably 2 to 3 hours.

In step (3), the temperature of the second reaction may be a temperature conventional in this type of reaction in the art, preferably 60 to 80 ℃.

In the step (3), the time of the second reaction may be a time which is conventional in the art in such a reaction, preferably 20 to 50 minutes, more preferably 30 to 50 minutes.

In step (3), the second reaction may further include a cooling operation, which may be generally performed by cooling to room temperature.

In the invention, the first reaction and the second reaction have no special meaning, and only the sequence of the reactions is shown here.

The invention provides a biomass adhesive, which is prepared by the preparation method of the biomass adhesive.

The invention also provides application of the biomass adhesive in the field of artificial boards as an adhesive.

On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the invention.

The reagents and materials used in the present invention are commercially available.

The invention has the positive progress effects that: according to the invention, lignin is modified and grafted with starch, and then the phenolic glue and the modified lignin grafted with starch are better combined by using a coupling agent, so that the novel biomass adhesive is prepared. The formaldehyde release amount of the biomass adhesive prepared by the invention is less than or equal to 0.05%, so that the environment-friendly adhesive with low formaldehyde or no formaldehyde release is prepared, and the environment-friendly adhesive is safe and pollution-free, and protects the environment and personnel safety; the cost is low, the bonding strength is good, and the application performance is excellent; lignin can be extracted from papermaking black liquor, so that the cost is further reduced, and waste is changed into valuable.

Detailed Description

The invention is further illustrated by means of the following examples, which are not intended to limit the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.

The preparation method of the papermaking black liquor used in the following examples comprises the following steps: steaming wood, 0.5mol/L sodium hydroxide aqueous solution and 0.1mol/L sodium sulfide aqueous solution, spraying, recovering steam, and washing to obtain sulfate pulp; the remainder of the material except the sulfate pulp is papermaking black liquor.

Example 1

(1) Firstly, 1L of papermaking black liquor is put into a container, water is added to prepare the solid content of 15%, stirring is started, the temperature is raised to 50 ℃, and the heat is preserved for 2 hours at the temperature; adding 30wt% sulfuric acid water solution to regulate the pH value of the system to 3.5, stirring for 30min, and suction filtering to collect filter cake; and flushing the filter cake with 500mL of purified water;

(2) Mixing the filter cake prepared in the step (1) with 30wt% ammonia water, wherein the mass ratio of the filter cake to the ammonia water is 1:3; transferring the mixture into a container, adding 30wt% hydrogen peroxide, wherein the mass ratio of filter cake to hydrogen peroxide is 3:1, adding 140mL of N, N-dimethylformamide, and stirring uniformly, wherein the mass ratio of lignin to N, N-dimethylformamide is 1:1.7, heating in a water bath at 50 ℃ for 30min, carrying out suction filtration, drying a filter cake in a drying oven at 100 ℃ for 5h, and finally crushing to obtain a dried mixed material A;

(3) 100g of dried mixture A, 25g of starch, 50g of ammonium persulfate, 0.1g of sodium dodecyl sulfate and 5 mass percent of N, N-dimethylformamide aqueous solution are taken for soaking, water bath heating is carried out at 80 ℃ for 2 hours, 100mL of polyvinyl alcohol aqueous solution with 3 mass percent is added, and the mass ratio of the dried mixture A to the polyvinyl alcohol is 1:0.031, the number average molecular weight of the polyvinyl alcohol is 18 ten thousand, and the mixture is aged for 8 hours after being stirred uniformly to prepare a mixed material B;

(4) Mixing the mixed material B prepared in the step (3) with 100mL of 4-tert-butylphenol, 80mL of 32% liquid alkali and 30mL of citral by mass percent, and uniformly stirring, wherein the mass ratio of the mixed material B to the 4-tert-butylphenol is 1:0.52, the mass ratio of the mixture B to the alkaline compound is 1:0.15, the mass ratio of the mixture B to the citral is 1:0.16; heating to 80 ℃, and adding 30g of zinc oxide to perform catalytic reaction for 2 hours; cooling, adding 10g of silane coupling agent vinyl trimethoxy silane and 20g of acrylamide, stirring at 80 ℃ for 30min, cooling and discharging to obtain the biomass adhesive.

Example 2

(1) Firstly, putting 2L of papermaking black liquor into a container, adding water to adjust the solid content to 20%, starting stirring, heating to 50 ℃, and preserving heat for 2 hours at the temperature; adding a sulfuric acid aqueous solution with the concentration of 30wt% to adjust the pH value of the system to 3, stirring for 30min, and then filtering to collect a filter cake; and flushing the filter cake with 800mL of purified water;

(2) Mixing the filter cake prepared in the step (1) with 30wt% ammonia water, wherein the mass ratio of the filter cake to the ammonia water is 1:3; transferring the mixture into a container, adding 30wt% hydrogen peroxide, wherein the mass ratio of filter cake to hydrogen peroxide is 3:1, adding 200mL of N, N-dimethylformamide, and stirring uniformly, wherein the mass ratio of lignin to N, N-dimethylformamide is 1:1.3, heating in a water bath at 50 ℃ for 30min, carrying out suction filtration, drying a filter cake in a baking oven at 100 ℃ for 4h, and finally crushing to obtain a dried mixed material A;

(3) 100g of dried mixture A, 35g of starch, 40g of ammonium persulfate, 0.05g of sodium dodecyl sulfate and 5% of N, N-dimethylformamide water solution by mass percentage are taken for soaking, water bath heating is carried out at 80 ℃ for 2 hours, 80mL of 5% of polyvinyl alcohol water solution by mass percentage is added, and the mass ratio of the dried mixture A to the polyvinyl alcohol is 1:0.042, the number average molecular weight of the polyvinyl alcohol is 20 ten thousand, and the mixture is aged for 8 hours after being uniformly stirred to prepare a mixed material B;

(4) Mixing the mixed material B prepared in the step (3) with 80mL of 4-tert-butylphenol, 60mL of 32% liquid alkali and 50mL of citral by mass percent, and uniformly stirring, wherein the mass ratio of the mixed material B to the 4-tert-butylphenol is 1:0.4, the mass ratio of the mixture B to the alkaline compound is 1:0.1, the mass ratio of the mixture B to the citral is 1:0.27; heating to 80 ℃, and adding 35g of zinc oxide to perform catalytic reaction for 2 hours; cooling, adding 8g of silane coupling agent vinyl trimethoxy silane and 20g of acrylamide, stirring at 80 ℃ for 30min, cooling and discharging to obtain the biomass adhesive.

Example 3

(1) Firstly, putting 2L of papermaking black liquor into a container, adding water to prepare the solid content of 18%, starting stirring, heating to 50 ℃, and preserving heat for 2 hours at the temperature; adding 30wt% sulfuric acid water solution to regulate the pH value of the system to 3.7, stirring for 30min, and suction filtering to collect filter cake; and washing the filter cake with 1000mL of pure water;

(2) Mixing the filter cake prepared in the step (1) with 30wt% ammonia water, wherein the mass ratio of the filter cake to the ammonia water is 1:3; transferring into a container, adding 30wt% hydrogen peroxide, adding 180mL of N, N-dimethylformamide into the container, and stirring uniformly, wherein the mass ratio of the lignin to the N, N-dimethylformamide is 1:1.2, heating in a water bath at 50 ℃ for 30min, carrying out suction filtration, drying a filter cake in a baking oven at 100 ℃ for 5h, and finally crushing to obtain a dried mixed material A;

(3) 200g of dried mixture A, 40g of starch, 80g of ammonium persulfate, 0.1g of sodium dodecyl sulfate and 5% of N, N-dimethylformamide water solution by mass percentage are taken for soaking, water bath heating is carried out at 80 ℃ for 2 hours, 150mL of 5% of polyvinyl alcohol water solution by mass percentage is added, and the mass ratio of the dried mixture A to the polyvinyl alcohol is 1:0.079, the number average molecular weight of the polyvinyl alcohol is 20 ten thousand, and the mixture is aged for 8 hours after being stirred uniformly to prepare a mixed material B;

(4) Mixing the mixed material B prepared in the step (3) with 180mL of 4-tert-butylphenol, 120mL of 32% liquid alkali and 40mL of citral by mass percent, and uniformly stirring, wherein the mass ratio of the mixed material B to the 4-tert-butylphenol is 1:0.5, the mass ratio of the mixture B to the alkaline compound is 1:0.1, the mass ratio of the mixture B to the citral is 1:0.1; heating to 80 ℃, and adding 50g of zinc oxide to perform catalytic reaction for 2 hours; cooling, adding 10g of silane coupling agent vinyl trimethoxy silane and 30g of acrylamide, stirring at 80 ℃ for 30min, cooling and discharging to obtain the biomass adhesive.

Comparative example 1

(2) Mixing the mixed filter cake prepared in the step (1) with 180mL of 4-tert-butylphenol, 120mL of liquid alkali with the mass percentage of 32% and 40mL of citral, and uniformly stirring; heating to 80 ℃, and adding 50g of zinc oxide to perform catalytic reaction for 2 hours; cooling, adding 10g of silane coupling agent vinyl trimethoxy silane and 30g of acrylamide, stirring at 80 ℃ for 30min, cooling and discharging to obtain the biomass adhesive.

Comparative example 2

Compared with the embodiment 1, the difference is that the adding sequence in the step (3) is different, specifically, 100g of the mixed material A, 25g of starch, 50g of ammonium persulfate, 0.1g of sodium dodecyl sulfate, 5% N, N-dimethylformamide water solution and 3% polyvinyl alcohol water solution are taken, 100mL of the mixed material A, soaked, heated in a water bath at 80 ℃ for 2h, stirred uniformly and aged for 8h, and the mixed material B is prepared.

Effect example 1

The biomass adhesives prepared by adopting the examples 1-3 and the comparative examples 1-2 are blended with filler flour, and the mass ratio of the biomass adhesives to the filler flour is 1:0.2, uniformly coating the mixed materials on a plate, carrying out double-sided sizing with the sizing amount of 330g/m ², pressing the plate in a plate pressing machine, and cold pressing for 1-1.5 h at room temperature, wherein the pressure is 1MPa; hot-pressing for 10-15 min at 100-150 deg.c under 1MPa; and then placing the mixture into an oven with the temperature of 60-75 ℃ for curing for 10-15 min to obtain the sample to be tested. Sampling and detecting formaldehyde emission data according to the national standard GBT 20974-2014, wherein the specification of a formaldehyde emission test sample is 15cm x 5cm; and the bonding strength is detected according to national standard GB/T17657-2013, and the bonding strength test sample has the specification that: 10cm x 2.5cm; the results are shown in Table 1 below.

TABLE 1

Numbering device	Bonding strength/MPa	Formaldehyde emission mg/L
			Example 1	1.33	0.01
Example 2	1.54	0.02
			Example 3	1.78	0.01
Comparative example 1	1.15	0.35
			Comparative example 2	1.19	0.22

From the effect data, each performance of the biomass adhesive prepared by the invention meets the national standard requirement. The biomass adhesive has wide sources of raw materials, low price, and can change waste into valuable and improve the resource utilization rate.

The above description is only a partial embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the technical scope of the present invention; the papermaking waste is related to other waste generated in the papermaking process, in addition to what is mentioned in the claims.

Claims

1. The preparation method of the biomass adhesive is characterized by comprising the following steps of:

(4) Mixing the mixed material B prepared in the step (3) with 100mL of 4-tert-butylphenol, 80mL of 32% liquid alkali and 30mL of citral by mass percent, and uniformly stirring, wherein the mass ratio of the mixed material B to the 4-tert-butylphenol is 1:0.52, the mass ratio of the mixture B to the alkaline compound is 1:0.15, the mass ratio of the mixture B to the citral is 1:0.16; heating to 80 ℃, and adding 30g of zinc oxide to perform catalytic reaction for 2 hours; cooling, adding 10g of silane coupling agent vinyl trimethoxy silane and 20g of acrylamide, stirring at 80 ℃ for 30min, cooling and discharging to obtain a biomass adhesive;

Or alternatively

(4) Mixing the mixed material B prepared in the step (3) with 80mL of 4-tert-butylphenol, 60mL of 32% liquid alkali and 50mL of citral by mass percent, and uniformly stirring, wherein the mass ratio of the mixed material B to the 4-tert-butylphenol is 1:0.4, the mass ratio of the mixture B to the alkaline compound is 1:0.1, the mass ratio of the mixture B to the citral is 1:0.27; heating to 80 ℃, and adding 35g of zinc oxide to perform catalytic reaction for 2 hours; cooling, adding 8g of silane coupling agent vinyl trimethoxy silane and 20g of acrylamide, stirring at 80 ℃ for 30min, cooling and discharging to obtain a biomass adhesive;

Or alternatively