CN108192564A - A kind of dregs of beans albumen adhesive and preparation method thereof - Google Patents

Abstract

The invention discloses a soybean meal protein adhesive and a preparation method thereof. The adhesive consists of 25 parts by weight of low-temperature defatted soybean meal protein powder, 65-70 parts by weight of dispersion medium water, 1-2 parts by weight of nano calcium carbonate, EMIBF ₄ 3 -4 parts by weight, 2-4 parts by weight of urea, and 4-5 parts by weight of cross-linking agent, the preparation method includes steps such as dispersion, high-pressure homogenizer homogeneous emulsification and ultrasonic treatment; the advantages of the present invention are: protein molecules Fully stretched or partially broken, the molecular weight decreases, the active group increases significantly, the degree of promoting the reaction between the crosslinking agent and the protein, and the crosslinking density increase significantly, and the adhesive has high water resistance and bonding performance, high stability, and good dry strength. The water resistance requirement of the plywood adhesive can be met, the cost of the adhesive is low, and the practical performance of the soybean meal protein adhesive is guaranteed.

Description

A kind of soybean meal protein adhesive and preparation method thereof

technical field

The invention relates to a soybean meal protein, in particular to a soybean meal protein adhesive and a preparation method thereof, which are used in the preparation of plywood and belong to the field of soybean meal protein.

Background technique

my country is short of precious wood resources, but there are abundant artificial forest resources. The wood-based panels prepared by using artificial forest fast-growing wood and agricultural and forestry processing residues through adhesives are the main raw materials for furniture floors and interior decoration in the living environment. In 2015, The total output of wood-based panels in my country is 310 million cubic meters, accounting for about 50% of the world's total output. Based on the average production of 9 cubic meters of wood-based panels per ton of adhesive, the consumption of wood adhesives in my country in 2015 was about 40 million tons (solid content 50%), of which urea-formaldehyde resin and its modified products accounted for 20% of the total output of adhesives. More than 90%, occupying a dominant position. Urea-formaldehyde resin adhesives are widely used in the wood industry due to their advantages, such as sufficient raw materials, low price, good water solubility, and light color of the adhesive layer. However, urea-formaldehyde resin also has some obvious disadvantages. In addition to poor aging resistance and water resistance, it cannot be used to prepare wood-based panels for outdoor use. Its fatal disadvantage is the release of formaldehyde from glued wood-based panels. With the improvement of people's quality of life and the enhancement of health and environmental awareness, people are paying more and more attention to the pollution of urea-formaldehyde resin adhesives to the living environment and the damage to people's health. The use of vegetable protein adhesives to prepare wood-based panels can solve the problem of free formaldehyde release from wood-based panels, but there is a problem of poor water-resistant bonding performance. Usually, a highly reactive cross-linking agent is added to form a network cross-linked structure to improve the water resistance of the adhesive. Adhesive performance, in order to reduce costs, common soybean meal is often used as raw material, but because soybean meal protein is insoluble in water, large in size, and low in reactivity, the raw material particles for preparing protein adhesives are not uniform, and a large number of weak interfacial layer crosslinking structure distributions are formed Unevenness, poor dry strength, and unstable bonding quality. Although the average strength meets the requirements, the bonding quality varies greatly in different areas of wood-based panels, and the product quality is unstable, which seriously affects its promotion.

Contents of the invention

In order to solve the above problems, the present invention designs a soybean meal protein adhesive and its preparation method, the protein molecules are fully stretched or partially broken, the molecular weight is reduced, the active groups are significantly increased, and the degree of reaction between the cross-linking agent and the protein, cross-linking The density is obviously increased, and the adhesive has high water-resistant bonding performance, high stability and good dry strength. The water resistance requirement of the plywood adhesive can be met, the cost of the adhesive is low, and the practical performance of the soybean meal protein adhesive is guaranteed.

Technical scheme of the present invention is:

A soybean meal protein adhesive, comprising the following components by weight:

25 parts by weight of low-temperature defatted soybean meal protein powder, 65-70 parts by weight of dispersion medium water, 1-2 parts by weight of nano calcium carbonate, 3-4 parts by weight of 1-methyl-3 ethylimidazole tetrafluoroboric acid (EMIBF ₄ ), urea 2-4 parts by weight, 4-5 parts by weight of crosslinking agent.

Wherein, the protein content in the low-temperature defatted soybean protein powder is 52% by mass, and the average particle size is 150-180 mesh. Low-temperature defatted soy protein powder can be purchased commercially, such as from Huifu Grain and Oil Co., Ltd., Zhoukou Yihai Grain and Oil Co., Ltd., China Cereals and Oils Co., Ltd., or prepared by conventional degreasing methods. The specific methods are not described in this invention. special limited.

Wherein, the above-mentioned crosslinking agent is trimethylolmelamine.

Among them, the above-mentioned chemical reagents including EMIBF ₄ , nano-calcium carbonate, and urea are all commercially available products, which can be purchased from Tianjin Chemical Co., Ltd., etc. Using the above-mentioned chemical reagent combination treatment method can effectively stretch and partially break protein molecules, promote the crystallization of protein molecules, increase the number and types of reactive groups on protein molecules, promote the reaction of soybean meal protein molecules with cross-linking agents, and form a denser cross-linking structure. Improve adhesive bonding performance.

The dispersion medium water is selected from ordinary tap water or demineralized water.

A preparation method of soybean meal protein adhesive, comprising the steps of:

(1) Weigh each component according to the weight ratio, evenly disperse the protein powder and urea in the dispersion medium water, and stir at 20°C for 20 minutes;

(2) Add nano-calcium carbonate to the mixture obtained in step (1), and use a high-pressure homogenizer to homogeneously emulsify for 20 minutes under the action of 30MPa pressure and 0.5MPa emulsifying force;

(3) Add the cross-linking agent and EMIBF ₄ to the mixture obtained in step (2), and use 20KHz ultrasonic treatment for 10 minutes to obtain the product.

The advantages of the present invention are:

1) The present invention adopts nano-calcium carbonate and high-pressure homogenization, and nano-ion is like a small millstone to promote the effect of high-pressure homogenization, so that the surface of protein particles is small and uniform, and the 3 and 4-level structure of protein after urea denaturation is further destroyed, and soybean protein molecules Fully stretched and partially broken, the number and types of active groups in the molecular system increase, and the reactivity increases. Ultrasound in the presence of ionic liquids destroys the primary and secondary structures of proteins, further stretches and even breaks the molecules, and further improves the reactivity; in addition, ultrasound in the presence of ionic liquids is conducive to the contact and combination of loose protein molecules and cross-linking agents , so that the cross-linking agent molecules can effectively and evenly embed protein molecules;

2) The present invention adopts the combination of nano-calcium carbonate/high-pressure homogenization and ionic liquid/ultrasound to make the protein particles uniform and stable, and the protein molecules change from a curled state to fully stretched and broken at room temperature, forming uniform small molecules with good permeability , the protein is closely combined with the cross-linking agent and is easy to react to prepare an adhesive to solve the problems of low dry strength and poor bonding stability of ordinary protein adhesives, and improve the reactivity, so that the types and quantities of protein molecules increase. Increased reactivity with cross-linking agents, reducing the amount of cross-linking agents used;

3) The present invention does not add toxic substances to the soybean meal protein adhesive, and uses the rigid nano-calcium carbonate, high-pressure homogenization process and ionic liquid to promote the green activation treatment of the protein, which has high efficiency and no harmful substance release. The product has high reactivity, and the combination of cross-linking agent under ultrasound to prepare adhesive can effectively improve the performance of the adhesive, reduce costs, and promote the application of protein adhesives;

The test proves that the adhesive of the present invention is easy to form a cross-linked structure, the cross-linking density is high, the reaction temperature is low, the performance of the prepared adhesive is stable, the weak interface layer is significantly reduced, the cost is reduced, the dry/wet strength is good, and the product quality is stably improved .

The present invention will be further described below in conjunction with specific examples.

Detailed ways

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Without departing from the spirit and essence of the present invention, any modifications or substitutions made to the methods, steps or conditions of the present invention fall within the scope of the present invention.

Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. In addition, all the component raw materials used in the examples are known commercially available products.

The percentage sign "%" involved in the present invention, if not specified, refers to mass percentage; but the percentage of solution, unless otherwise specified, refers to the number of grams of solute contained in 100ml of solution; the percentage between liquids is Refers to the ratio of capacity at 20°C.

Example 1

Example 1

This embodiment provides a method for preparing a soybean meal protein adhesive, and the adhesive is prepared according to the following weight ratio:

Demineralized water 75 kg

Defatted Soy Protein Powder 25 kg

EMIBF ₄ 3kg

Nano calcium carbonate 1kg

Urea 2kg

Cross-linking agent 4Kg

Among them, defatted soy protein powder with a protein content of more than 52% was purchased from Huifu Grain and Oil Co., Ltd.; other materials were purchased from Beijing Chemical Reagent Co., Ltd.

This embodiment also provides the preparation method of the above-mentioned adhesive, and the specific preparation steps are as follows:

(1) Weigh each component according to the weight ratio, evenly disperse the protein powder and urea in the dispersion medium water, and stir at 20°C for 20 minutes;

(2) Add nano-calcium carbonate to the mixture obtained in step (1), and use a high-pressure homogenizer to homogeneously emulsify for 20 minutes under the action of 30MPa pressure and 0.5MPa emulsifying force;

(3) Add the cross-linking agent and EMIBF ₄ to the mixture obtained in step (2), and use 20KHz ultrasonic treatment for 10 minutes to spray dry.

Example 2

This embodiment provides a method for preparing a soybean meal protein adhesive, and the adhesive is prepared according to the following weight ratio:

Demineralized water 75 kg

Defatted Soy Protein Powder 25 kg

EMIBF ₄ 4kg

Nano calcium carbonate 2kg

Urea 4kg

Cross-linking agent 5kg

Among them, defatted soy protein powder with a protein content of more than 52% was purchased from Huifu Grain and Oil Co., Ltd.; other materials were purchased from Beijing Chemical Reagent Co., Ltd.

The preparation method of the adhesive described in this embodiment is the same as that in Example 1.

Comparative example 1-3

Compared with Example 1-2 respectively, the control group 1 is ordinary soybean meal protein powder plus cross-linking agent; Add cross-linking agent after mean; control group 4 and control group 2 add cross-linking agent and EMIBF ₄ and perform sonication.

Test case

Three-layer plywood was prepared by using the active soybean meal protein adhesives of Examples 1-2 of the present invention and Comparative Examples 1-4, respectively.

Poplar veneer: dry to 10% moisture content; size 40cm*40cm*0.15cm.

According to the following normal preparation process:

Glue sizing: the amount of glue applied is 400g/m ² .

Pressure, temperature, time: 0.8MPa, 110°C, 6 minutes.

According to the test method of GB/T17657-1999 "Physical and Chemical Properties of Wood-Based Panels and Decorated Wood-based Panels", the performance test of the horizontal panel products is carried out. The test results are shown in Table 1.

Table 1 Bonding strength of plywood

The experimental results show that the soybean meal protein adhesive of the present invention improves the water-resistant bonding performance of the prepared plywood, and the bonding strength is more than 1.20MPa according to the detection of II plywood, and can reach more than 12 hours of boiling without opening glue, and the dry strength is more than 1.2, which is higher than that of the control group. It has increased by about 50%. The standard deviation calculation shows that the stability of the adhesive prepared from soybean meal protein adhesive is significantly improved, and the enhancement effect is remarkable.

Although the present invention has been described in detail with general descriptions and specific embodiments above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (5)

1. A soybean meal protein adhesive, characterized in that: comprising the following components by weight: 25 parts by weight of low-temperature defatted soybean meal protein powder, 65-70 parts by weight of dispersion medium water, 1-2 parts by weight of nano-calcium carbonate, 3-4 parts by weight of EMIBF ₄ , 2-4 parts by weight of urea, and 4-5 parts by weight of crosslinking agent . 2. A soybean meal protein adhesive according to claim 1, characterized in that: the protein content in the low-temperature defatted soybean protein powder is 52% by mass, and the particle size is 150-180 mesh. 3. A soybean meal protein adhesive according to claim 1, characterized in that: the cross-linking agent is trimethylol melamine. 4. A soybean meal protein adhesive according to claim 1, characterized in that: ordinary tap water or demineralized water is selected as the dispersion medium water. 5. a kind of preparation method of a kind of soybean meal protein adhesive as described in any one of claim 1-4, is characterized in that, comprises the steps: (1) Weigh each component according to the weight ratio, evenly disperse the protein powder and urea in the dispersion medium water, and stir at 20°C for 20 minutes; (2) Add nano-calcium carbonate to the mixture obtained in step (1), and use a high-pressure homogenizer to homogeneously emulsify for 20 minutes under the action of 30MPa pressure and 0.5MPa emulsifying force; (3) Add the cross-linking agent and EMIBF ₄ to the mixture obtained in step (2), and use 20KHz ultrasonic treatment for 10 minutes to obtain the product.