CN110655902A - Adhesive and preparation method and application thereof - Google Patents

Abstract

The invention discloses an adhesive and a preparation method and application thereof. The adhesive has the effects of zero formaldehyde, high bonding strength and the like.

Description

Adhesive and preparation method and application thereof

Technical Field

The invention belongs to the field of fine chemical engineering, and particularly relates to an adhesive and a preparation method thereof.

Background

At present, the wood adhesive industry is more and more inclined to prepare formaldehyde-free, green and environment-friendly wood adhesives by using biomass materials. The current adhesives based on biomass materials mainly comprise tannin, lignin, starch, protein and the like. In the adhesives, biomass powder filler adhesives are the mainstream of research and development, and are currently used in the production of artificial boards in large scale abroad. Although the formaldehyde emission of the current domestic adhesive is far lower than that of a formaldehyde-formaldehyde adhesive, the adhesive still has a plurality of problems in the gluing performance, such as easy cracking under the condition of high-temperature boiling, easy moisture absorption and mildew generation under some high-humidity environments in the south and the like, deviation of water resistance, low initial adhesion strength and difficult gluing, so that the further application of the adhesive is limited.

Disclosure of Invention

In view of the above disadvantages of the prior art, the present invention aims to provide an adhesive for artificial boards, which is free of formaldehyde, high in adhesive strength, good in water resistance, good in anti-mildew effect, and easy to apply glue, and a preparation method thereof.

In order to achieve the above objects and other objects, the present invention is achieved by the following technical solution, wherein the adhesive comprises mixed protein, mixed gel, at least one alkaline solution, a crosslinking agent, a thermosetting resin, and at least one polymer additive, wherein a mass ratio of the mixed protein to the thermosetting resin is (0.5-1.5): (1.5-3).

As a further improvement of the above scheme, the adhesive comprises 75-125 parts by mass of mixed protein, 10-42 parts by mass of mixed gel, 10-50 parts by mass of at least one alkali solution, 1-8 parts by mass of a cross-linking agent, 90-150 parts by mass of a thermosetting resin and 0.5-15 parts by mass of at least one polymer additive, wherein the mass ratio of the mixed protein to the thermosetting resin is (1-1.5): (2-3).

As a further improvement of the above, the mixed protein comprises one or more of soybean meal, peanut meal, corn meal and wheat starch. The mixed protein is powdery and has no caking. The mixed protein is white or light yellow. The mixed protein has no peculiar smell. The mixed protein content (on a dry basis) is greater than 50% and the crude fiber content (on a dry basis) is less than 4%. The crude fat content (on a dry basis) of the mixed protein is less than 2.0%. The mixed protein comprises 35-60 parts by mass of soybean protein powder, 15-35 parts by mass of peanut powder, 15-35 parts by mass of corn flour and 3-20 parts by mass of wheat starch.

As a further improvement of the scheme, the mixed gel is a mixture of egg white protein, carrageenan and gelatin. The mixed gel comprises 5-25 parts by mass of egg white protein, 3-12 parts by mass of carrageenin and 2-15 parts by mass of gelatin; the egg white protein glue is an egg white colloid component of poultry eggs or duck eggs.

As a further improvement of the above aspect, the thermosetting resin comprises a polyamide polyamine epichlorohydrin resin. The preparation method of the polyamide polyamine epichlorohydrin comprises the following steps,

dripping polyethylene polyamine into adipic acid to obtain a polyamide polyethylene polyamine aqueous solution;

and (3) dropwise adding epichlorohydrin into the aqueous solution of the polyamide-polyethylene polyamine to obtain the polyamide-polyamine epichlorohydrin resin.

As a further improvement of the above aspect, the alkaline solution includes one or more of a sodium hydroxide solution, a sodium carbonate solution, and a sodium bicarbonate solution. The mass fraction of the alkali solution is 3-12%.

As a further improvement of the above aspect, the polymeric additive includes one or more of a tackifying resin, a surfactant, and a biocide. The bactericide is a compound mixed bactericide of a mildew-proof bactericide and a glutaraldehyde solution, and the compound mass ratio is 2:1-5: 1.

As a further improvement of the above aspect, the cross-linking agent is a combination of glyoxal and glutaraldehyde.

The invention also relates to a preparation method of the adhesive, which at least comprises the following steps,

carrying out heat treatment on the mixed protein through the alkaline solution to obtain a first pretreatment solution;

adding said mixed gel and at least one of said polymeric additives to said first pre-treatment fluid to obtain a second pre-treatment fluid;

and mixing the second pretreatment liquid with the thermosetting resin, and adding a cross-linking agent to obtain the adhesive.

The invention also relates to an application of the adhesive in artificial boards.

Drawings

Fig. 1 is a schematic flow chart of a method according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention is provided by way of specific examples, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. It is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the respective manufacturers.

When numerical ranges are given in the examples, it is understood that both endpoints of each of the numerical ranges and any value therebetween can be selected unless the invention otherwise indicated. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs and the description of the present invention, and any methods, apparatuses, and materials similar or equivalent to those described in the examples of the present invention may be used to practice the present invention.

Note that "%" and "part(s)" shown in the description herein mean "% by mass" and "part(s) by mass", respectively, unless otherwise specified.

Fig. 1 is a schematic flow chart of a method for preparing an adhesive according to an embodiment of the present invention, which at least includes the following steps,

s1, carrying out heat treatment on the mixed protein through the alkaline solution to obtain a first pretreatment solution;

s2, adding the mixed gel and at least one polymer additive into the first pretreatment solution to obtain a second pretreatment solution;

s3, mixing the second pretreatment liquid with the thermosetting resin, and adding a cross-linking agent to obtain the adhesive.

Specifically, in S1, the alkaline solution includes one or more of a sodium hydroxide solution, a sodium carbonate solution, and a sodium bicarbonate solution. The mass fraction of the alkaline solution is 3-12%. The alkaline solution pretreats the mixed protein, so that protein molecular chains in the mixed protein are degraded in the heat treatment process, and more functional groups such as amino groups, carboxyl groups and the like are exposed.

The biomass powder such as soybean meal, peanut powder and the like becomes an important raw material of the wood adhesive because of containing a large amount of protein molecules, but the biomass powder is difficult to meet the application requirement because of poor water resistance and poor anti-mildew performance, so that the performance of the wood adhesive is improved by pretreating mixed protein by using an alkaline solution and matching with other mixed gel components. The method comprises the following steps of weighing 75-125 parts by mass of mixed protein, 10-42 parts by mass of mixed gel, 10-50 parts by mass of at least one alkaline solution, 1-8 parts by mass of a cross-linking agent, 90-150 parts by mass of a thermosetting resin and 0.5-15 parts by mass of at least one polymer additive, wherein the mass ratio of the mixed protein to the thermosetting resin is (1-1.5): (2-3), placing 35-60 parts by mass of soybean flour, 15-35 parts by mass of peanut flour, 15-35 parts by mass of corn flour and 3-20 parts by mass of wheat flour in a three-necked bottle, adding 3-12% by mass of alkaline solution, pretreating at 65-95 ℃ for 1-5 hours, and cooling to room temperature of 25-30 ℃ to obtain a first pretreatment solution. The mixed protein meets the following conditions of powder shape, no caking phenomenon, white or light yellow, no peculiar smell, no foreign substances visible to naked eyes, protein content (calculated by dry basis) > 50%, crude fiber content (calculated by dry basis) < 4%, crude fat content (calculated by dry basis) < 2.0%, solubility value of KOH water soluble protein 65% -80%, urease activity 0.05-0.5 delta pH, fineness of 110-.

In various embodiments, the soy flour may also be used in an amount of 35-40 parts by mass, 55-60 parts by mass, 50-55 parts by mass, or 45-50 parts by mass. The amount of the peanut powder also comprises 19-25 parts by mass, 16-18 parts by mass or 15-16 parts by mass. The amount of the corn flour also comprises 15-18 parts by mass, 16-18 parts by mass, 15-16 parts by mass or 18-20 parts by mass. The wheat flour is used in an amount of 5-8 parts by mass, 10-11 parts by mass, 12-14 parts by mass or 10-11 parts by mass. The dosage proportion of the soybean meal, the peanut meal, the corn meal and the wheat meal in different embodiments influences the adhesive bonding strength of the adhesive. The mass ratio of the mixed protein to the thermosetting resin also comprises 0.8-1:2-2.5, 1-1.5: 3. 0.9-1.1:2.6 or 1-1.5: 2.8. The step of pretreating at 65-95 ℃ for 1-5 hours further comprises pretreating at 80-85 ℃ for 1-2 hours, at 90-95 ℃ for 1-1.5 hours, or at 70-75 ℃ for 1-2 hours.

Specifically, in S2, the polymer additive includes one or more of a tackifying resin, a surfactant, and a biocide. The bactericide is a compound mixed bactericide of a mildew-proof bactericide and a glutaraldehyde solution, and the compound mass ratio is 2:1-5: 1. The method comprises the specific steps of adding 5-25 parts by mass of egg white protein, 3-12 parts by mass of carrageenan and 2-15 parts by mass of gelatin into the first pretreatment liquid, stirring for 0.5-1 hour, uniformly mixing, adding a surfactant such as sodium dodecyl benzene sulfonate and an anti-mildew bactericide, reacting at room temperature for 0.5-2 hours, taking out for later use, and obtaining a second pretreatment liquid. The mixed gel is introduced as a raw material, so that not only can the cost be reduced, but also more functional groups can be exposed on protein molecular chains by matching with alkaline solution, the initial viscosity of the product is increased, meanwhile, the impermeability of the gel can be further reduced, the permeation of glue to a plate can be further reduced, meanwhile, the doping of the gel is more beneficial to the elastic bonding of a bonding layer, the problem that the glue layer is hardened after the glue is completely cured is avoided, and the problem that the glue layer is easy to crack and split under the action of external force is greatly reduced.

In different embodiments, the amount of the egg white protein further comprises 5-10 parts by mass, 12-15 parts by mass or 16-20 parts by mass. The amount of the carrageenan is 5-8 parts by mass, 6-8 parts by mass or 8-10 parts by mass. The gelatin is used in an amount of 3-6 parts by mass, 6-8 parts by mass, 8-10 parts by mass or 10-12 parts by mass. The compound mass ratio of the mixed bactericide also comprises 1.5-2:1, 2-3:1, 3-4:1 or 2-2.5: 1.

Specifically, in S3, the thermosetting resin includes a polyamide polyamine epichlorohydrin resin, and the thermosetting resin has a solid content of 10 to 15%. The synthesis step of the polyamide polyamine epichlorohydrin resin comprises the steps of dropwise adding polyethylene polyamine into adipic acid to obtain an aqueous solution of polyamide polyethylene polyamine; and (3) dropwise adding epichlorohydrin into the aqueous solution of the polyamide-polyethylene polyamine to obtain the polyamide-polyamine epichlorohydrin resin. In different embodiments, the amount of the adipic acid comprises 100-115 parts by mass, 106-109 parts by mass, 108-109 parts by mass or 105-110 parts by mass. The polyethylene polyamine comprises 80-90 parts by mass of diethylenetriamine, 70-78 parts by mass of diethylenetriamine, 90-95 parts by mass of triethylenetetramine or 75-80 parts by mass of diethylenetriamine. The time for dripping the polyethylene polyamine also comprises 0.5-1 hour, 0.2-0.5 hour or 0.5-0.6 hour. The thermosetting resin introduced by the invention has good water resistance after curing, can realize stable adhesion after hot pressing of the plate, and simultaneously, a large number of active functional groups such as amino groups and the like contained on the molecular chain of the thermosetting resin can further react with functional groups such as hydroxyl groups in plant powder, hydroxyl groups on fibers on the surface of the plate and the like, thereby further obviously enhancing the bonding strength through chemical bonding, and simultaneously, the thermosetting resin also has strong water resistance after curing.

Mixing the second pretreatment liquid with the thermosetting resin according to the following ratio of (0.1-2): (1-5) mixing uniformly at room temperature, adding a cross-linking agent, mixing and stirring for 10-30 minutes, adding 3-15 parts by mass of soybean powder and 5-10 parts by mass of corn flour, further adjusting the viscosity of the glue by using tackifying resin to enable the glue to be capable of gluing and the glue not to penetrate through the plate, placing for 5-10 minutes after mixing uniformly, and then starting gluing, wherein the tackifying resin is one or a combination of a modified rosin resin aqueous solution or a terpene resin emulsion, and the introduced tackifying resin can not only adjust the viscosity of the glue, but also improve the water resistance of the adhesive prepared by the invention. The cross-linking agent is a molecular-level cross-linking network formed by the reaction of a protein molecular chain promoting degradation and thermosetting resin, so that the water resistance of the adhesive is further improved, the cross-linking agent is a combination of glyoxal and glutaraldehyde, and the glutaraldehyde in the combination has the mildew-proof and sterilization effects on the adhesive.

The glue applying method of the adhesive comprises the following steps of uniformly coating the adhesive on the surface of a plate to be bonded, wherein the glue applying amount is 250-²The curing period and the open period after coating are controlled to be 20-100 minutes; then the plates are jointed and then are put on a hot press, the gradient hot pressing is carried out for 0.5 to 2.5 hours under the conditions that the pressure is 1.0 to 2.0MPa and the temperature is 120-165 ℃, and then the plates are taken out and cooled to be molded. In various embodiments, the sizing amount further comprises 250-260g/m²、280-300g/m²、420-450g/m²Or 380-400g/m². The process under the conditions of the pressure of 1.0-2.0MPa and the temperature of 120-165 ℃ also comprises the conditions of the pressure of 0.8-2.0MPa and the temperature of 110-165 ℃.

In one embodiment, the invention provides a preparation method of an adhesive, which specifically comprises the following steps of weighing 35-40 parts by mass of soybean flour, 19-25 parts by mass of peanut flour, 15-18 parts by mass of corn flour and 5-8 parts by mass of wheat flour in a three-necked bottle, adding 15-19 parts by mass of 3-12% alkaline solution, pretreating at 80-85 ℃ for 1-2 hours, cooling to room temperature of 25-30 ℃, adding a certain amount of 5-10 parts by mass of egg white protein, 5-8 parts by mass of carrageenan and 3-6 parts by mass of gelatin, stirring for 0.5-1 hour, uniformly mixing, adding 3-5 parts by mass of a surfactant such as sodium dodecyl benzene sulfonate, and 2-5 parts by mass of a mixed bactericide, the mass ratio of the bactericide to the glutaraldehyde solution with the mass fraction of 10-12.5% in the mixed bactericide is 1.5-2:1, and then the mixed bactericide is taken out for later use after reacting for 0.5-1 hour at room temperature.

The invention further improves the adhesive bonding strength and the water resistance of the board by synthesizing the polyamide epichlorohydrin with a certain molecular weight and introducing the polyamide epichlorohydrin into the pretreatment liquid of the mixed protein. The specific synthesis steps are as follows: firstly, weighing 115 parts by mass of adipic acid and 5-10 parts by mass of water, placing the adipic acid and the water in a three-necked bottle, dropwise adding 80-90 parts by mass of diethylenetriamine at 50-60 ℃, controlling the dropwise adding time to be 0.5-1 hour, heating to 160-165 ℃ after the dropwise adding is finished, reacting for 1-2 hours, then cooling, adding 200 parts by mass of 80-90 ℃ hot water for diluting, finally obtaining a bright yellow polyamide-polyethylene polyamine aqueous solution, taking out for later use, and dropwise adding epichlorohydrin to the polyamide-polyethylene polyamine aqueous solution to obtain the polyamide-polyamine epichlorohydrin resin.

Uniformly mixing the pretreatment solution prepared in the two steps and a thermosetting resin aqueous solution at room temperature according to the proportion of 0.8-1:2-2.5, then adding 1-2 parts of a cross-linking agent, mixing and stirring for 10-30 minutes, supplementing 3-5 parts by mass of soybean protein powder and 4-6 parts by mass of corn flour during stirring, and further adjusting the viscosity of glue by utilizing tackifying resin to enable the glue to reach the viscosity capable of gluing and enabling the glue not to penetrate a plate. After mixing, the glue was allowed to stand for 5-10 minutes before application of the glue was initiated, sample a was obtained in this example.

The glue applying method of the adhesive comprises the following steps of firstly processing and preparing a wood board into six square small boards of 8cm x 8cm, for example, then pretreating the boards for 10 to 30 minutes in a wet environment with humidity of 75 to 80 percent, then taking the boards out and respectively and uniformly coating the adhesives on the surfaces of the boards to be bonded, wherein the glue applying amount is 250-²Spreading, standing at 25-30 deg.C, and controlling the aging period and open period at 20-100 min; then the plates are jointed on a hot press under the pressure of 0.8-2.0MPa and the temperature of 110-165 DEG CUnder the condition of gradient hot pressing for 0.5-0.6 h, the heating rate at the temperature of 110-2 ℃/min and the temperature of 150-165 ℃ is 1.5-2 ℃/min, then the mixture is taken out after heat preservation for 3-6 min at the temperature of 160-165 ℃ and cooled to form the mold.

In one embodiment, the invention provides a preparation method of an adhesive, which specifically comprises the following steps of weighing 55-60 parts by mass of soybean meal, 16-18 parts by mass of peanut powder, 16-18 parts by mass of corn flour and 10-11 parts by mass of wheat flour in a three-necked bottle, adding 15-19 parts by mass of an alkaline solution with the mass fraction of 3-12%, pretreating at 90-95 ℃ for 1-1.5 hours, cooling to the room temperature of 25-30 ℃, adding a certain amount of 12-15 parts by mass of egg white protein, 6-8 parts by mass of carrageenan and 6-8 parts by mass of gelatin, stirring for 0.5-1 hour, uniformly mixing, adding 4-5 parts by mass of surfactant sodium dodecyl benzene sulfonate and 6-7 parts by mass of a mixed bactericide, wherein the mass ratio of the bactericide to a glutaraldehyde solution with the mass fraction of 10-12.5% is 2 3:1, then reacting at room temperature for 0.5-1 hour, and taking out for later use.

The invention further improves the adhesive bonding strength and the water resistance of the board by synthesizing the polyamide epichlorohydrin with a certain molecular weight and introducing the polyamide epichlorohydrin into the pretreatment liquid of the mixed protein. The specific synthesis steps are as follows: firstly, 106-109 mass parts of adipic acid and 6-8 mass parts of water are weighed and placed in a three-neck bottle, 70-78 mass parts of diethylenetriamine is dripped at 50-60 ℃, the dripping time is controlled to be 0.2-0.5 hour, the mixture is heated to 160-165 ℃ after the dripping is finished and reacts for 1.5-2 hours, then the mixture is cooled and is added with 180 mass parts of 80-90 ℃ hot water for dilution, finally, the bright yellow polyamide-polyethylene polyamine aqueous solution is obtained, the mixture is taken out for later use, and epichlorohydrin is dripped into the polyamide-polyethylene polyamine aqueous solution to obtain the polyamide-polyamine epichlorohydrin resin.

The pretreatment solution and the thermosetting resin aqueous solution prepared by the two steps are mixed according to the weight ratio of 1-1.5: 3, adding 1-2 parts by mass of a cross-linking agent, mixing and stirring for 10-30 minutes, supplementing 4-6 parts by mass of soybean protein powder and 2-4 parts by mass of corn flour during stirring, and further adjusting the viscosity of the glue by utilizing tackifying resin to enable the glue to reach the viscosity capable of gluing and enabling the glue not to penetrate the board. After mixing, the glue was allowed to stand for 5-10 minutes before application of glue was initiated, sample B was obtained in this example.

The glue applying method of the adhesive comprises the following steps of firstly processing and preparing a wood board into six square small boards of 8cm x 8cm, for example, then pretreating the boards for 10 to 30 minutes in a wet environment with humidity of 75 to 80 percent, then taking the boards out and respectively and uniformly coating the adhesives on the surfaces of the boards to be bonded, wherein the glue applying amount is 280-300 g/m-²Placing at 25-30 deg.C after coating, and controlling the aging period and open period at 20-100 min; then after the plates are jointed, the plates are subjected to gradient hot pressing for 0.5 to 0.6 hours on a hot press under the conditions that the pressure is 0.8 to 2.0MPa and the temperature is 110-165 ℃, the heating rate at 110-150 ℃ is 1 to 2 ℃/min, and the temperature at 150-165 ℃ is 1.5 to 2 ℃/min, then the plates are taken out after being subjected to heat preservation for 3 to 6 minutes at 160-165 ℃, and then the plates are taken out and cooled to be molded.

In one embodiment, the invention provides a preparation method of an adhesive, which specifically comprises the following steps of weighing 50-55 parts by mass of soybean meal, 15-16 parts by mass of peanut powder, 15-16 parts by mass of corn flour and 12-14 parts by mass of wheat flour, placing the soybean meal, 15-16 parts by mass of corn flour and 12-14 parts by mass of wheat flour in a three-necked bottle, adding 20-22 parts by mass of 3-12% alkaline solution, pretreating at 70-75 ℃ for 1-2 hours, cooling to room temperature of 25-30 ℃, adding a certain amount of 16-20 parts by mass of egg white protein, 6-8 parts by mass of carrageenan and 8-10 parts by mass of gelatin, stirring for 0.5-1 hour, uniformly mixing, adding 5-7 parts by mass of surfactant sodium dodecyl benzene sulfonate and 5-6 parts by mass of mixed bactericide, the mass ratio of the bactericide to the glutaraldehyde solution with the mass fraction of 10-12.5% in the mixed bactericide is 3-4:1, and the mixed bactericide is taken out for later use after reacting for 0.5-1 hour at room temperature.

The invention further improves the adhesive bonding strength and the water resistance of the board by synthesizing polyamide epichlorohydrin with certain molecular weight and introducing the polyamide epichlorohydrin into the pretreatment solution of the mixed protein. The specific synthesis steps are as follows: firstly, 108-109 parts by mass of adipic acid and 9-10 parts by mass of water are weighed and placed in a three-neck flask, 90-95 parts by mass of triethylene tetramine is dripped at 50-60 ℃, the dripping time is controlled to be 0.5-0.6 hour, the mixture is heated to 150-160 ℃ after the dripping is finished and reacts for 1-2 hours, then the mixture is cooled and is diluted by adding 280 parts by mass of 80-90 ℃ hot water, finally, the bright-brown polyamide polyethylene polyamine aqueous solution is obtained, the mixture is taken out for later use, and epichlorohydrin is dripped into the polyamide polyethylene polyamine aqueous solution to obtain the polyamide polyamine epichlorohydrin resin.

Uniformly mixing the pretreatment solution and the thermosetting resin aqueous solution prepared in the two steps at room temperature according to the ratio of 0.9-1.1:2.6, then adding 3-3.5 parts by mass of a cross-linking agent, mixing and stirring for 10-30 minutes, supplementing 6-8 parts by mass of soybean protein powder and 1-2 parts by mass of corn flour during stirring, and further adjusting the viscosity of the glue by utilizing tackifying resin to enable the glue to reach the viscosity capable of gluing and enabling the glue not to penetrate the board. After mixing, the glue was allowed to stand for 5-10 minutes before application of glue was initiated, sample C was obtained in this example.

The glue applying method of the adhesive comprises the following steps of firstly processing and preparing a wood board into six square small boards of 8cm x 8cm, for example, then pretreating the boards for 10 to 30 minutes in a wet environment with humidity of 75 to 80 percent, then taking out the boards and respectively and uniformly coating the adhesives on the surfaces of the boards to be bonded, wherein the glue applying amount is 420-²Placing at 25-30 deg.C after coating, and controlling the aging period and open period at 20-100 min; then, after the plates are attached, the plates are placed on a hot press, gradient hot pressing is carried out for 0.5 to 0.6 hours under the conditions that the pressure is 0.8 to 2.0MPa and the temperature is 110-165 ℃, the heating rate at 110-150 ℃ is 2 ℃/min, the temperature at 150-165 ℃ is 1.5 to 2 ℃/min, then the plates are taken out after heat preservation is carried out for 3 to 6 minutes at 160-165 ℃, and then the plates are taken out and cooled to be molded.

In one embodiment, the present invention provides a method for preparing an adhesive, which specifically comprises the following steps: firstly, weighing 45-50 parts by mass of soybean meal, 15-16 parts by mass of peanut powder, 18-20 parts by mass of corn flour and 10-11 parts by mass of wheat flour in a three-necked bottle, then adding 18-21 parts by mass of 3-12% alkaline solution, pretreating at 80-85 ℃ for 1-2 hours, cooling to room temperature of 25-30 ℃, then adding a certain amount of 12-15 parts by mass of egg white protein, 8-10 parts by mass of carrageenan and 10-12 parts by mass of gelatin, stirring for 0.5-1 hour, uniformly mixing, and then adding 4-5 parts by mass of sodium dodecyl benzene sulfonate as a surfactant and 4-5 parts by mass of a mixed bactericide. The mass ratio of the bactericide to the glutaraldehyde solution with the mass fraction of 10-12.5% in the mixed bactericide is 2-2.5:1, and then the mixed bactericide is taken out for later use after reacting for 0.5 hour at room temperature.

The invention further improves the adhesive bonding strength and the water resistance of the board by synthesizing the polyamide epichlorohydrin with a certain molecular weight and introducing the polyamide epichlorohydrin into the pretreatment liquid of the mixed protein. The specific synthesis steps are as follows: firstly, weighing 110 parts by mass of adipic acid and 6-8 parts by mass of water, placing the adipic acid and the water in a three-necked bottle, dropwise adding 75-80 parts by mass of diethylenetriamine at 50-60 ℃, controlling the dropwise adding time to be 0.5-1 hour, heating to 150-160 ℃ after the dropwise adding is finished, reacting for 1-2 hours, then cooling, adding 175 parts by mass of hot water at 80-90 ℃ to dilute the mixture, finally obtaining a bright yellow polyamide-polyethylene polyamine aqueous solution, taking out the solution for later use, and dropwise adding epichlorohydrin to the polyamide-polyethylene polyamine aqueous solution to obtain the polyamide-polyamine epichlorohydrin resin.

Uniformly mixing the pretreatment solution prepared in the two steps and a thermosetting resin aqueous solution at room temperature according to the proportion of 1-1.5:2.8, then adding 2-3 parts by mass of a cross-linking agent, mixing and stirring for 10-30 minutes, supplementing 4-5 parts by mass of soybean protein powder and 4-5 parts by mass of corn flour during stirring, and further adjusting the viscosity of the glue by utilizing tackifying resin to enable the glue to reach the viscosity capable of gluing and enabling the glue not to penetrate the board. After mixing, the glue was allowed to stand for 5-10 minutes before application of glue was initiated, sample D was obtained in this example.

The glue applying method of the adhesive comprises the following steps of firstly processing and preparing a wood board into six square small boards of 8cm x 8cm, for example, then pretreating the boards for 10 to 30 minutes in a wet environment with humidity of 75 to 80 percent, then taking out the boards and respectively and uniformly coating the adhesives on the surfaces of the boards to be bonded, wherein the glue applying amount is 380-²Placing at 25-30 deg.C after coating, and controlling the aging period and open period at 20-100 min; then the plates are jointed and then are placed on a hot press under the conditions that the pressure is 0.8-2.0MPa and the temperature is 110-165 DEG CHot pressing at a lower gradient for 0.6 hour, with the heating rate of 1-2 ℃/min at the temperature of 110-165 ℃ and 1.5-2 ℃/min at the temperature of 150-165 ℃, then taking out after heat preservation for 3-6 minutes at the temperature of 160-165 ℃, and then taking out and cooling to obtain the final product.

Adhesive performance test meter

Note: the test data are tested by adopting a hot-pressing blockboard.

The invention realizes the high-efficiency bonding of 6-8 layers of blockboards and plywood and excellent water boiling resistance by a method of gradient heating of the glued boards. Compared with the existing soy protein-based adhesive, the adhesive prepared by the invention has the characteristics of zero formaldehyde, high bonding strength, good water resistance, mildew resistance, easiness in gluing and the like, the bonding strength reaches the relevant standard of home plate bonding, and the application requirement and the environmental protection requirement of the plate adhesive for furniture life are met.

Furthermore, it is to be understood that one or more method steps mentioned in the present invention does not exclude that other method steps may also be present before or after the combined steps or that other method steps may also be inserted between these explicitly mentioned steps, unless otherwise indicated; it should also be understood that unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention which may be practiced, nor is it intended to limit the relative changes or modifications to the scope of the invention which may be practiced without materially changing the technical details.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (10)

1. An adhesive, comprising: the composite material comprises mixed protein, mixed gel, at least one alkaline solution, a cross-linking agent, a thermosetting resin and at least one polymer additive, wherein the mass ratio of the mixed protein to the thermosetting resin is (0.5-1.5): (1.5-3).

2. The adhesive of claim 1, wherein said adhesive comprises,

75-125 parts by mass of mixed protein,

10 to 42 parts by mass of a mixed gel,

10 to 50 parts by mass of at least one alkali solution,

1 to 8 parts by mass of a crosslinking agent,

90 to 150 parts by mass of a thermosetting resin and

0.5-15 parts by mass of at least one polymer additive, wherein the mass ratio of the mixed protein to the thermosetting resin is (1-1.5): (2-3).

3. The adhesive of claim 1 wherein said protein blend comprises one or more of soy flour, peanut flour, corn flour, and wheat starch.

4. An adhesive according to claim 1, wherein said mixed gel is a mixture of egg white protein, carrageenan and gelatin.

5. An adhesive according to claim 1, wherein said thermosetting resin comprises a polyamide polyamine epichlorohydrin resin.

6. An adhesive according to claim 5, wherein said polyamide polyamine epichlorohydrin is prepared by a process comprising,

dripping polyethylene polyamine into adipic acid to obtain a polyamide polyethylene polyamine aqueous solution;

and (3) dropwise adding epichlorohydrin into the aqueous solution of the polyamide-polyethylene polyamine to obtain the polyamide-polyamine epichlorohydrin resin.

7. An adhesive according to claim 1, wherein the polymeric additive comprises one or more of a tackifying resin, a surfactant and a biocide.

8. The adhesive of claim 1 wherein said cross-linking agent is a combination of glyoxal and glutaraldehyde.

9. A process for the preparation of the adhesive according to any of claims 1 to 8, characterized in that it comprises at least the following steps,

carrying out heat treatment on the mixed protein through the alkaline solution to obtain a first pretreatment solution;

adding said mixed gel and at least one of said polymeric additives to said first pre-treatment fluid to obtain a second pre-treatment fluid;

and mixing the second pretreatment liquid with the thermosetting resin, and adding a cross-linking agent to obtain the adhesive.

10. Use of the adhesive according to any one of claims 1-8 in artificial boards.

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