Starch-based furfuryl alcohol adhesive for wood and preparation method of starch-based furfuryl alcohol adhesive

Abstract

The invention discloses a starch-based furfuryl alcohol adhesive for wood. The starch-based furfuryl alcohol adhesive is prepared from the following raw materials in parts by mass: 5 to 10 parts of furfuryl alcohol, 20 to 30 parts of glyoxal, 30 to 40 parts of urea, 20 to 30 parts of starch, 10 to 15 parts of styrene-butadiene latex, 3 to 5 parts of melamine and 3 to 5 parts of polyvinyl alcohol. The invention also provides a preparation method of the starch-based furfuryl alcohol adhesive for wood. The environment-friendly glyoxal, starch, furfuryl alcohol and butylbenzene are used for synthesizing the bio-based adhesive, and through a plywood process, the problem of formaldehyde release is effectively solved, the working environment is improved, damage to human bodies is reduced, and meanwhile, the water resistance is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of wood adhesive preparation, in particular to a starch-furfuryl alcohol adhesive for wood and a preparation method thereof. Background Art

[0002] Urea-formaldehyde resin is the most widely used wood adhesive. Due to its high bonding strength, simple production process and low cost, it is widely used in wood adhesives and is the most widely used wood adhesive among trialdehyde adhesives. However, urea-formaldehyde resin has problems such as poor water resistance and high free formaldehyde, which seriously limit the application of urea-formaldehyde resin. In addition, the free formaldehyde in urea-formaldehyde resin will be released, causing great problems to the health of workers and subsequent use. Therefore, how to reduce the release of harmful chemicals in the resin, such as various monomers, to reduce pollution and improve the production and working environment has become a major problem faced by related companies.

[0003] Invention patent CN118460155 The present invention relates to a highly water-resistant urea-formaldehyde resin adhesive and a preparation method thereof, which uses formaldehyde and is harmful to the human body and the environment; CN117987052 The present invention discloses a preparation method of a modified urea-formaldehyde resin adhesive, comprising: screening raw materials of soy protein, polyurethane and lignan, but the strength is poor.

[0004] Traditional wood adhesives use formaldehyde. As the country's requirements on formaldehyde content become more and more stringent, and even require no formaldehyde, formaldehyde-free adhesives are increasingly valued by scientific researchers. Bio-based adhesives, starch-based adhesives, and protein-based adhesives have emerged.

[0005] The problem to be solved by the present invention is to provide a starch-based furfuryl alcohol adhesive for wood and a preparation method thereof, so as to solve the above-mentioned technical problems existing in the prior art. Summary of the invention

[0006] To solve the above problems, the present invention provides the following technical solutions.

[0007] A starch-based furfuryl alcohol adhesive for wood, wherein the weight percentages of the components in the raw materials are: 5-10 parts of furfuryl alcohol, 20-30 parts of glyoxal, 30-40 parts of urea, 20-30 parts of starch, 10-15 parts of styrene-butadiene latex, 3-5 parts of melamine and 3-5 parts of polyvinyl alcohol.

[0008] The present invention also provides a method for preparing a starch-furfuryl alcohol adhesive for wood, which specifically comprises the following steps:

[0009] (1) adding 5-10 parts of glyoxal to a reaction kettle, adding alkali to adjust the pH to 8-10, starting stirring, and adding 3-5 parts of melamine and 3-5 parts of polyvinyl alcohol to react;

[0010] (2) adding 20-30 parts of starch into water to prepare a starch aqueous solution having a starch content of 40-50%; adding the starch aqueous solution into a reaction kettle to react;

[0011] (3) Add 20-30 parts of urea, add alkali to maintain the pH value, and raise the temperature to 70-85°C to continue the reaction;

[0012] (4) adding 5-10 parts of furfuryl alcohol, adding acid to adjust the pH value of the system to acidic, and reacting to the end point;

[0013] (5) cooling, adding alkali to adjust the system to weak alkalinity, adding 10-15 parts of styrene-butadiene latex to continue the reaction, and cooling and discharging the materials after the reaction is completed to obtain a starch-furfuryl alcohol adhesive.

[0014] Preferably, in step (1), the reaction conditions are: temperature 60-70° C., and reaction time 0.5-2 h.

[0015] Preferably, in step (2), the reaction conditions are: temperature 60-70° C., reaction time 0.5-1 h.

[0016] Preferably, in step (3), the reaction conditions are: reaction time 1-2h.

[0017] Preferably, in step (4), the reaction conditions are: reacting at 80-90° C., adjusting the pH to 4.5-6, and reacting for 1-2 h.

[0018] Preferably, in step (5), the reaction conditions are: reacting at 80-90° C. and adjusting the pH to 7-8.

[0019] Preferably, the base used to adjust the pH value includes sodium hydroxide, potassium hydroxide, triethanolamine, ammonia water, sodium carbonate, potassium carbonate, barium hydroxide or one or more of their aqueous solutions.

[0020] Preferably, the acid used to adjust the acidic pH value includes one or more of formic acid, acetic acid, benzenesulfonic acid, hydrochloric acid and sulfuric acid.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention utilizes environmentally friendly glyoxal, starch, furfuryl alcohol and butadiene benzene to synthesize a bio-based adhesive, and effectively solves the formaldehyde release problem through a plywood process.

[0023] 2. The starch-based furfuryl alcohol adhesive prepared by the present invention has no formaldehyde pollution, and at the same time effectively improves water resistance, improves the working environment, and reduces damage to human body. DETAILED DESCRIPTION

[0024] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0025] Example 1

[0026] A method for preparing a starch-furfuryl alcohol adhesive for wood, the specific steps comprising:

[0027] (1) Add 5 parts of glyoxal into a reaction kettle, add alkali to adjust the pH to 8, start stirring, add 3 parts of melamine and 3 parts of polyvinyl alcohol to react, and react at 60° C. for 0.5 h;

[0028] (2) adding 20 parts of starch into water to prepare a starch aqueous solution with a starch content of 40%; adding the above starch aqueous solution into a reaction kettle and reacting at 60° C. for 0.5 h;

[0029] (3) Add 20 parts of urea, add alkali to maintain the pH at 8, raise the temperature to 70-85°C and continue the reaction for 0.5h;

[0030] (4) Add 5 parts of furfuryl alcohol, add acid to adjust the pH value of the system to 4.5, and react for 1 hour;

[0031] (5) Cooling, adding alkali to adjust the pH to 7, adding 10 parts of butylbenzene and stirring for 0.5 hours, cooling and discharging the materials to obtain a starch-based furfuryl alcohol adhesive.

[0032] Example 2

[0033] A method for preparing a starch-furfuryl alcohol adhesive for wood, the specific steps comprising:

[0034] (1) Add 8 parts of glyoxal into a reaction kettle, add alkali to adjust the pH to 8, start stirring, add 4 parts of melamine and 4 parts of polyvinyl alcohol to react, and react at 60° C. for 0.5 h;

[0035] (2) adding 25 parts of starch into water to prepare a starch aqueous solution with a starch content of 45%; adding the above starch aqueous solution into a reaction kettle and reacting at 60° C. for 0.5 h;

[0036] (3) Add 25 parts of urea, add alkali to maintain the pH at 9, raise the temperature to 70-85°C and continue the reaction for 0.5h;

[0037] (4) adding 8 parts of furfuryl alcohol, adding acid to adjust the pH value of the system to 6, and reacting for 1 hour;

[0038] (5) Cooling, adding alkali to adjust the pH to 7, adding 10 parts of butylbenzene and stirring for 0.5 hours, cooling and discharging the materials to obtain a starch-based furfuryl alcohol adhesive.

[0039] Example 3

[0040] A method for preparing a starch-furfuryl alcohol adhesive for wood, the specific steps comprising:

[0041] (1) Add 10 parts of glyoxal into a reaction kettle, add alkali to adjust the pH to 10, start stirring, add 5 parts of melamine and 5 parts of polyvinyl alcohol to react, and react at 60° C. for 0.5 h;

[0042] (2) adding 30 parts of starch into water to prepare a starch aqueous solution with a starch content of 45%; adding the above starch aqueous solution into a reaction kettle and reacting at 60° C. for 0.5 h;

[0043] (3) Add 30 parts of urea, add alkali to maintain the pH at 10, raise the temperature to 70-85°C and continue the reaction for 0.5h;

[0044] (4) adding 10 parts of furfuryl alcohol, adding acid to adjust the pH value of the system to 5, and reacting for 1 hour;

[0045] (5) Cooling, adding alkali to adjust the pH to 7, adding 15 parts of butadiene, stirring for 0.5 h, cooling and discharging, and obtaining a starch-based furfuryl alcohol adhesive.

[0046] Comparative Example 1

[0047] Same as Example 2, except that glyoxal is not included.

[0048] Comparative Example 2

[0049] Same as Example 2, except that furfural is not included.

[0050] Comparative Example 3

[0051] Same as Example 2, except that starch is not included.

[0052] Comparative Example 4

[0053] Same as Example 2, except that butadiene is not included.

[0054] Comparative Example 5

[0055] Commercially available urea-formaldehyde resin (Henan Yuansheng New Materials Co., Ltd.).

[0056] Implementation effect:

[0057] The national standard GB / T 14732-2017 urea-formaldehyde, phenol-formaldehyde, melamine-formaldehyde resins for wood industry adhesives and the standard GB / T 9846-2015 ordinary plywood were used to measure the various indicators of each resin obtained in the above embodiments and comparative examples. The specific test results are shown in Table 1, where the bonding strength is the average strength of 8 samples.

[0058] Table 1 Test results of various adhesive indicators

[0059]

[0060] As can be seen from the above, compared with the comparative example, in the embodiments of the present invention, the content of free formaldehyde and formaldehyde emission is very small, which improves the working environment, reduces the physical damage to workers, and is very beneficial to the environment. In addition, the water resistance of each adhesive obtained by the present invention also meets the requirements, and the improvement of water resistance expands the application range of the adhesive. In addition, the cost of the adhesive manufactured according to the present invention is not much different from that on the market, and the improvement of cost can also be accepted by the market.

[0061] The above are only preferred embodiments of the present invention. Those skilled in the art should understand that the present invention is not limited to these embodiments. The above embodiments and descriptions only describe the principles of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A starch-furfuryl alcohol adhesive for wood, characterized in that: The mass proportions of the components in the raw materials are as follows: 5-10 parts of furfuryl alcohol, 20-30 parts of glyoxal, 30-40 parts of urea, 20-30 parts of starch, 10-15 parts of styrene-butadiene latex, 3-5 parts of melamine and 3-5 parts of polyvinyl alcohol.

2. The method for preparing a starch-furfuryl alcohol adhesive for wood according to claim 1, wherein: The specific steps include: (1) adding 5-10 parts of glyoxal to a reaction kettle, adding alkali to adjust the pH to 8-10, starting stirring, and adding 3-5 parts of melamine and 3-5 parts of polyvinyl alcohol to react; (2) adding 20-30 parts of starch into water to prepare a starch aqueous solution having a starch content of 40-50%; adding the starch aqueous solution into a reaction kettle to react; (3) Add 20-30 parts of urea, add alkali to maintain the pH value, and raise the temperature to 70-85°C to continue the reaction; (4) adding 5-10 parts of furfuryl alcohol, adding acid to adjust the pH value of the system to acidic, and reacting to the end point; (5) cooling, adding alkali to adjust the system to weak alkalinity, adding 10-15 parts of styrene-butadiene latex to continue the reaction, and cooling and discharging the materials after the reaction is completed to obtain a starch-furfuryl alcohol adhesive.

3. The method for preparing a starch-furfuryl alcohol adhesive for wood according to claim 2, wherein: In the step (1), the reaction conditions are: temperature 60-70° C., reaction time 0.5-2 h.

4. The method for preparing a starch-furfuryl alcohol adhesive for wood according to claim 2, wherein: In the step (2), the reaction conditions are: temperature 60-70°C, reaction time 0.5-1h.

5. The method for preparing a starch-furfuryl alcohol adhesive for wood according to claim 2, characterized in that: In the step (3), the reaction conditions are: reaction time 1-2h.

6. The method for preparing a starch-furfuryl alcohol adhesive for wood according to claim 2, characterized in that: In the step (4), the reaction conditions are: reacting at 80-90° C., adjusting the pH to 4.5-6, and reacting for 1-2 hours.

7. The method for preparing a starch-furfuryl alcohol adhesive for wood according to claim 2, characterized in that: In the step (5), the reaction conditions are: reacting at 80-90° C. and adjusting the pH to 7-8.

8. The method for preparing a starch-furfuryl alcohol adhesive for wood according to claim 2, characterized in that: The alkali used to adjust the pH value includes sodium hydroxide, potassium hydroxide, triethanolamine, ammonia water, sodium carbonate, potassium carbonate, barium hydroxide or one or more of their aqueous solutions.

9. The method for preparing a starch-furfuryl alcohol adhesive for wood according to claim 2, characterized in that: The acid used to adjust the acidic pH value includes one or more of formic acid, acetic acid, benzenesulfonic acid, hydrochloric acid, and sulfuric acid.

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