CN105969303B - A kind of dregs of beans base timber adhesive and preparation method thereof - Google Patents

Abstract

The invention discloses a soybean meal-based wood adhesive and a preparation method thereof. It is prepared from 20 parts and 65-73 parts of dispersion medium, and the preparation method includes the steps of dispersing, mixing, heating and stirring; the advantage of the present invention is that it can meet the water resistance requirements of the adhesive for wood-based panels and ensure the practical performance of the protein adhesive; It completely solves the formaldehyde pollution problem in indoor air caused by wood-based panels; the main raw materials are renewable resources, which conform to the principles of environmental protection and sustainable development.

Description

A kind of soybean meal-based wood adhesive and preparation method thereof

technical field

The invention relates to an adhesive and a preparation method thereof, in particular to a soybean meal-based wood adhesive and a preparation method thereof, belonging to the field of adhesives and the preparation thereof.

Background technique

With the improvement of people's living standards and the continuous and stable development of construction, decoration, packaging and other industries, the output of wood-based panels in my country has grown rapidly. In 2014, the total output of wood-based panels in China was 302 million m ³ , accounting for more than 50% of the world's total output. Among them, particleboard was 17 million m ³ , a year-on-year increase of 13%; fiberboard was 69 million m ³ , a year-on-year increase of 16%; plywood was 174 million m ³ , a year-on-year increase of 7%. The total output of wood-based panels, plywood, furniture, and wood flooring has ranked first in the world for many years in a row.

The adhesives commonly used in the production of wood-based panels are formaldehyde-based synthetic resins, mainly urea-formaldehyde resins and their modified products. After years of hard work, the production level of wood-based panel adhesives in my country has been greatly improved, and the environmental protection characteristics of wood-based panels and their products have been greatly improved, but the formaldehyde release of their products cannot be completely eliminated, and many enterprises produce wood-based panels and their products. (Furniture, wood flooring, indoor wood decoration materials, etc.) still have a serious problem of formaldehyde release, which is the main source of formaldehyde pollution in indoor air pollution.

At present, there are mainly four methods to reduce the release of formaldehyde from wood-based panels: 1) Using low molar ratio modified urea-formaldehyde resin adhesive; 2) Adding formaldehyde scavenger to the modified urea-formaldehyde resin adhesive; 3) Post-treatment of wood-based panels ; 4) Use other environmentally friendly adhesives. But all there are many defectives in these technical methods. For example: 1) Although the use of low molar ratio modified urea-formaldehyde resin adhesives can effectively reduce the formaldehyde emission of wood-based panel products, the bonding strength of the products is often reduced, which cannot meet the requirements of use; and it can lead to prolonged curing time and reduced production efficiency; 2) Adding formaldehyde scavenger to urea-formaldehyde resin adhesives for wood-based panels can effectively reduce the release of free formaldehyde from wood-based panels, but it often reduces the bonding strength of wood-based panels at the same time; at the same time, the price of general formaldehyde scavenger is often much higher than that of urea-formaldehyde resin adhesives. Adding improves product cost and reduces product competitiveness; 3) Carry out post-processing to wood-based panels, as the invention patent application with publication number CN1526528 discloses a method for preparing E1/EO grade environment-friendly wood-based panels using ammonia vacuum method. Manufacturing process; the utility model patent with publication number CN2394770 discloses a treatment device for reducing formaldehyde emission from wood-based panels. These post-processing methods not only make the manufacturing process of wood-based panels complicated, but also require huge investment in post-processing equipment and significantly increase production costs. ; 4) The use of other environmentally friendly adhesives, such as isocyanate adhesives, has led to a substantial increase in the production cost of wood-based panels and increased difficulty in the production process, which is difficult for enterprises and users to accept; Open glue. To sum up, although the above measures can effectively reduce the release of free formaldehyde from wood-based panels, they cannot completely solve the problem of formaldehyde release, or cannot be popularized due to reasons such as high production costs.

In addition, the currently widely used wood-based panel adhesives also have the problem of dependence on fossil resources of raw materials, which do not meet the requirements of sustainable development.

Contents of the invention

In order to solve the above problems, the present invention designs a soybean meal-based wood adhesive and a preparation method thereof, which can meet the water resistance requirements of the adhesive for wood-based panels and ensure the practical performance of the protein adhesive; thoroughly solve the problem of indoor air caused by wood-based panels Formaldehyde pollution problem; the main raw materials are renewable resources, in line with the principles of environmental protection and sustainable development.

Technical scheme of the present invention is:

A soybean meal-based wood adhesive, comprising the following components by weight:

20-40 parts of defatted protein powder, 0.0005-0.005 parts of viscosity reducer, 0.1-5.0 parts of emulsifier, 1-5 parts of denaturant, 1-30 parts of reinforcing agent, and 60-80 parts of dispersion medium.

Preferably, the soybean meal-based wood-based panel adhesive includes the following components in parts by weight: 27-33 parts of defatted protein powder, 0.001-0.003 parts of viscosity reducer, 0.5-2.0 parts of emulsifier, and 1-2 parts of denaturant , 7-20 parts of reinforcing agent, 65-73 parts of dispersion medium.

Wherein, the protein content in the defatted protein powder is more than 40%, preferably 43-50%, so as to ensure a more ideal application effect and control costs.

The defatted protein powder can be selected from one or more of defatted soybean protein powder, defatted peanut protein powder, defatted cotton meal powder, defatted blood protein powder, defatted feather protein powder, and defatted bone protein powder, among which defatted soybean protein powder is preferred protein powder or nonfat peanut protein powder.

Further, the particle size of the defatted protein powder is greater than 150 mesh, preferably 200-250 mesh.

The defatted soybean protein powder, defatted peanut protein powder, defatted cottonseed meal powder, defatted blood protein powder, defatted feather protein powder and defatted bone protein powder of the present invention are all commercially available, such as can be purchased from Huifu Grain and Oil Co., Ltd., Zhoukou Yihai Cereals and Oils Co., Ltd., China Cereals and Oils Co., Ltd., etc., or prepared by a conventional degreasing method, and the specific method is not particularly limited in the present invention.

Described viscosity reducing agent is a kind of in papain, bromelain, neutral protease.

The emulsifier is one of polyacrylamide, polyvinyl alcohol and polyetherimide.

The denaturant is selected from one or more of sodium dodecylbenzenesulfonate, urea, guanidine hydrochloride, and sodium carbonate.

The above-mentioned denaturants are all commercially available products, which can be purchased from Tianjin Chemical Co., Ltd., etc. The use of the above-mentioned denaturant can depolymerize the protein molecule to expose the active groups inside the molecule, which is conducive to the reaction with the added enhancer to form a denser cross-linked network, laying the foundation for strengthening the adhesive; the use of a viscosity reducer can degrade the protein molecule, A large number of small molecular proteins are produced. On the one hand, the degradation of molecular chains to form a large number of small molecular proteins is conducive to the exposure of functional groups in the protein. On the other hand, the degradation of small molecular proteins by macromolecular proteins will greatly reduce the viscosity of the adhesive, and the generated small molecular proteins are conducive to penetration. More glue nails are formed in the wood, which increases the dry and wet bonding strength of the adhesive; the use of emulsifiers can make the components of the adhesive mix more uniformly, promote the effective contact of each component, and the added emulsifier can also participate in the reaction and interact with the adhesive system Form a cross-linked network structure.

The enhancer denaturant is selected from one of urea, guanidine hydrochloride, and sodium carbonate (10% solution).

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

The present invention also provides a kind of preparation method of adhesive for artificial board simultaneously, comprises the following steps:

1) Weigh the protein powder, emulsifier, and denaturant according to the weight ratio and disperse them evenly in the dispersion medium, raise the temperature of the water bath to 30°C and stir for 20 minutes;

2) Heat the water bath to 50°C, add the viscosity reducer and stir for 10 minutes, then continue to heat up to 90°C and stir for 20 minutes to inactivate the protease.

3) Cool down to 20°C, add enhancer, and stir evenly.

The advantages of the present invention are:

1) The present invention uses denaturants, emulsifiers, and viscosity reducers to work together, so that soybean protein molecules are stretched from curly macromolecules and then cut into short molecular chain proteins, and are uniformly dispersed under the action of emulsifiers, which is the role of subsequent enhancers. Addition provides suitable molecular weight and large amount of reactive functional groups, and reduces viscosity.

2) The present invention prepolymerizes the adhesive with tannin-resorcinol-glutaraldehyde after denaturation, so that the reinforcing agent interacts with soybean protein molecules to form a cross-linked interpenetrating network structure, which solves the problem of poor water resistance of ordinary protein adhesives 1. The problem of poor water boiling resistance can meet the water-resistant requirements of the adhesive for wood-based panels, ensuring the practical performance of the protein adhesive, and the plywood prepared by the adhesive of the present invention meets the requirements of class II plywood in the national standard;

3) The present invention prepolymerizes tannin-resorcinol-glutaraldehyde as a raw material and uses it as an adhesive for wood-based panels after modification. It does not contain free formaldehyde, and the glued wood-based panels do not have the problem of formaldehyde release, which completely solves the problem of man-made panels. The problem of formaldehyde pollution in indoor air caused by boards;

4) Protein powder and tannin are renewable resources. As the main raw materials of adhesives, they help to solve the problem of depletion of synthetic fossil raw materials used in conventional wood-based panel adhesives, and are in line with the principles of environmental protection and sustainable development;

5) Effective use of agricultural and sideline product processing residues and paper industry waste, comprehensive utilization of resources, saving production costs and increasing the added value of products.

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 the mass percentage of the index finger; but the percentage of the solution, unless otherwise specified, refers to the number of grams of solute contained in 100ml of the solution; the percentage between liquids is Refers to the ratio of capacity at 20°C.

Example 1

This embodiment provides an adhesive for wood-based panels, and the adhesive is prepared according to the following weight ratio:

Demineralized water 73 kg

Defatted Soy Protein Powder 27 kg

Denaturant 1.0kg

Viscosity reducer 0.001kg

Emulsifier 0.5kg

Enhancer 7kg

Among them, the protein content of defatted soybean protein powder is more than 43% (purchased from Huifu Grain and Oil Co., Ltd.); the denaturant is commercially available common guanidine hydrochloride, the viscosity reducer is papain, and the emulsifier is polyvinyl alcohol (purchased from Beijing Chemical Reagent Co., Ltd. Co., Ltd., content 99%); the reinforcing agent is self-made tannin-resorcinol-glutaraldehyde prepolymer (solid content 60%, viscosity 2400mPa.s).

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

1) In a mixer equipped with a stirrer, add all the demineralized water, defatted soybean protein powder, emulsifier, and denaturant, stir evenly, heat up to 30°C and stir for 20 minutes.

2) Raise the temperature to 50°C, add the viscosity reducing agent and stir for 10 minutes, continue to raise the temperature to 90°C and stir for 20 minutes to inactivate the protease.

3) Cool down to 20°C, add enhancer, and stir evenly.

The properties and quality indicators of the obtained adhesive are shown in Table 1.

Example 2

This embodiment provides an adhesive for wood-based panels, and the adhesive is prepared according to the following weight ratio

Tap water 71 kg

Defatted Soy Protein Powder 29 kg

Denaturant 1.5kg

Viscosity reducer 0.002kg

Emulsifier 1.0kg

Enhancer 12kg

Among them, the protein content of defatted soybean protein powder is more than 43% (purchased from Huifu Grain and Oil Co., Ltd.); the denaturant is commercially available urea, the viscosity reducing agent is bromelain, and the emulsifier is polyacrylamide (purchased from Beijing Chemical Reagent Co., Ltd. , content 99%); the enhancer is self-made tannin-resorcinol-glutaraldehyde prepolymer (solid content 60%, viscosity 2400mPa.s).

The preparation method of the adhesive described in this example is the same as in Example 1, and the performance and quality indicators of the obtained adhesive are shown in Table 1.

Example 3

This embodiment provides an adhesive for wood-based panels, and the adhesive is prepared according to the following weight ratio:

Demineralized water 69 kg

Defatted Peanut Protein Powder 31 kg

Denaturant 1.0kg

Viscosity reducer 0.002kg

Emulsifier 1.5kg

Enhancer 18kg

Among them, the protein content of defatted soybean protein powder is more than 43% (purchased from Huifu Grain and Oil Co., Ltd.); the denaturant is commercially available urea, the viscosity reducing agent is neutral protease, and the emulsifier is polyetherimide (purchased from Beijing Chemical Industry Co., Ltd. Reagent Co., Ltd., content 99%); the enhancer is self-made tannin-resorcinol-glutaraldehyde prepolymer (solid content 60%, viscosity 2400mPa.s).

The preparation method of the adhesive described in this example is the same as in Example 1, and the performance and quality indicators of the obtained adhesive are shown in Table 1.

Example 4

This embodiment provides an adhesive for wood-based panels, and the adhesive is prepared according to the following weight ratio:

Demineralized water 67 kg

Defatted Peanut Protein Powder 33 kg

Denaturant 2.0kg

Viscosity reducer 0.003kg

Emulsifier 2.0kg

Enhancer 20kg

Among them, the protein content of defatted soybean protein powder is more than 43% (purchased from Huifu Grain and Oil Co., Ltd.); the denaturant is commercially available ordinary sodium carbonate, the viscosity reducer is bromelain, and the emulsifier is polyetherimide (purchased from Beijing Chemical Reagent Co., Ltd., content 99%); the enhancer is self-made tannin-resorcinol-glutaraldehyde prepolymer (solid content 60%, viscosity 2400mPa.s).

The preparation method of the adhesive described in this example is the same as in Example 1, and the performance and quality indicators of the obtained adhesive are shown in Table 1.

Table 1 Performance indicators of the adhesive prepared in Examples 1-4

Comparative example 1-8

Compared with Examples 1-4 respectively, the control groups 1-4 are adhesives without adding denaturant, viscosity reducer and emulsifier in sequence.

Compared with Examples 1-4 respectively, the control groups 5-8 are adhesives without reinforcing agent.

Comparative example 9

Commercially available 50% solid content low free formaldehyde content melamine modified urea-formaldehyde resin adhesive (the specific formula is: the addition of melamine is 10% of the total weight of the adhesive, the molar ratio is 1.18, and the urea is divided into three batches and the molar ratio is respectively 2.1, 1.45 , 1.18, melamine was added with the second batch of urea, purchased from Xuzhou Anlian Wood Industry Co., Ltd.)

Test case

The adhesives of Examples 1-4 of the present invention and Comparative Examples 1-9 were used to manufacture three layers of 400×400mm plywood.

Poplar veneer: dry to 6-14% moisture content; thickness 1.6mm;

The veneer adhesive used the products of Examples 1-5 of the present invention and the products of Comparative Examples 1-10.

Plywood is prepared according to the normal process as follows:

Glue sizing: Glue is applied on both sides of the core board, and the amount of glue applied is 300-460g/m ² .

Aging method and time: closed aging, 10-30 minutes.

Pre-compression pressure and time: pre-compression 30-40 minutes, pressure 0.8MPa.

Hot pressing pressure: 1.0MPa, hot pressing temperature: 110-120°C, hot pressing time: 70-90s/mm.

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 produced plywood products is carried out. The test results are shown in Table 2.

Table 2 Formaldehyde emission and bonding strength of plywood

The experimental results show that the formaldehyde emission of the plywood manufactured by the formaldehyde-free biomass adhesive of the present invention is very low (for the release of formaldehyde from the wood body), and the bonding strength of the plywood prepared by the biomass adhesive added with the reinforcing agent is detected by II plywood above 1.10MPa , can be boiled for 10 hours without opening the glue, and the dry strength is above 1.2, which is about 50% higher than that of the control group, and the enhancement effect is remarkable.

The formaldehyde-free protein adhesive of the present invention is easy to use, does not need to modify the existing wood-based panel production equipment and process, and therefore does not need to increase equipment investment.

The adhesive prepared by the invention can replace the conventional formaldehyde-containing adhesive for plywood, and the total amount of glue applied when preparing the plywood remains unchanged, so the use cost is equivalent to that of the modified urea-formaldehyde resin adhesive. Therefore, the protein adhesive of the present invention has good application prospects.

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 (7)

1. a kind of wood adhesive, it is characterised in that：Include the component of following parts by weight：

27-33 parts of defatted protein powder, 1-2 parts of denaturant, 7-20 parts of reinforcing agent, 65-73 parts of decentralized medium；The reinforcing agent is one Tannin-resorcinol-glutaraldehyde the prepolymer prepared under fixed condition.

2. a kind of wood adhesive according to claim 1, it is characterised in that：The defatted protein powder is selected from degreasing beans egg One in white powder, defatted peanut protein powder, defatted cotton dregs powder, degreasing hemalbumin powder, degreasing feather albumen powder, degreasing bone protein powder Kind is several.

3. a kind of wood adhesive according to claim 1, it is characterised in that：The grain size of the defatted protein powder is all higher than 150 mesh.

4. a kind of wood adhesive according to claim 1, it is characterised in that：The denaturant be selected from urea, guanidine hydrochloride, One kind in sodium carbonate.

5. a kind of wood adhesive according to claim 1, it is characterised in that：Further include thinner 0.0005-0.005 Part, the one kind of the thinner in papain, bromelain, neutral proteinase.

6. a kind of wood adhesive according to claim 1, it is characterised in that：Further include 0.1-5.0 parts of emulsifier, it is described Emulsifier is selected from polyacrylamide or polyvinyl alcohol.

7. a kind of wood adhesive according to claim 1, it is characterised in that：The decentralized medium selects ordinary tap water Or softened water.