Woodworking adhesive and preparation method thereof

Abstract

The invention discloses a woodworking adhesive and a preparation method thereof, and the woodworking adhesive comprises the following components in parts by weight: 58-62 parts of a silicone acrylic emulsion, 12-14 parts of a VAE emulsion, 18-22 parts of lignin A, 1-3 parts of zirconium acetate, 1-3 parts of a silane coupling agent, 1-2 parts of a defoaming agent and 2-3 parts of a thickening agent. The adhesive prepared from the lignin A can be applied to plywood with poplar, oak and birch as base materials, the prepared plywood is not prone to warping and deformation, the bonding strength of the plywood is obviously higher than that of class I and class II national standards, and compared with competitive products, the lignin woodworking adhesive prepared through the method has obvious advantages in the aspects of bonding strength and the like. And low-cost waste materials are recycled, so that new balance of environment, society and economy can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesives, and in particular relates to a woodworking adhesive and a preparation method thereof. Background Art

[0003] Lignin is the second most abundant natural polymer in the plant kingdom and the only one containing aromatic rings. It is considered to be an excellent substitute for fossil energy due to its many different types of functional groups in its structure and its natural renewability, easy degradation, and non-toxicity. It is widely used in metallurgy, medicine, construction, home furnishing and other fields. Common lignin is recovered and extracted from pulping waste liquid. Lignin is obtained by alkali recovery and membrane separation. However, both methods have their own inevitable limitations. The alkali recovery method has a simple process, but high energy consumption and low returns. The membrane separation method can obtain high-purity alkali lignin, but it is easy to clog the ultrafiltration membrane and affect its service life.

[0004] In view of the above problems, the present invention discloses a method for extracting highly active lignin from disposable chopsticks, and making it into woodworking adhesive. On the one hand, by recycling disposable chopsticks, the pollution to the environment is reduced, wood resources are saved, and the felling of trees is reduced, which helps to reduce carbon emissions and combat climate change; on the other hand, the lignin A prepared by the present invention is used in woodworking adhesives. Since lignin A can undergo in-situ self-crosslinking and its crosslinking reaction with native lignin in plant cell walls, the addition of lignin A can significantly improve the bonding strength of the adhesive on plywood, and has good performance in bonding three substrates of poplar, oak and birch. Summary of the invention

[0005] The purpose of the present invention is to provide a woodworking adhesive and a preparation method thereof in view of the deficiencies in the prior art.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a woodworking adhesive, which comprises, by weight, 58 to 62 parts of silicone-acrylic emulsion, 12 to 14 parts of VAE emulsion, 18 to 22 parts of lignin A, 1 to 3 parts of zirconium acetate, 1 to 3 parts of silane coupling agent, 1 to 2 parts of defoaming agent, and 2 to 3 parts of thickener.

[0008] Furthermore, the lignin A is prepared by the following method, in parts by weight:

[0009] (1) using a garden grinder to crush the disposable chopsticks into particles, and using a grinder to grind the particles into wood powder with a particle size of 0.02 to 10 μm, preferably 0.5 to 1.5 μm;

[0010] (2) mixing choline chloride and oxalic acid hexahydrate in a molar ratio of 1:1 to 1.2, stirring and reacting at 90 to 110° C. for 1.5 to 2.5 hours to prepare a transparent and uniform low eutectic solvent;

[0011] (3) Weigh 18 to 24 parts of a deep eutectic solvent into a reaction kettle, add 5 to 7 parts of wood powder, heat and stir at 120 to 140° C. for 1 to 2 hours to obtain a solution a;

[0012] (4) then placing solution a in a water bath and subjecting it to ultrasonic treatment at 70-90° C. for 0.5-1.5 h;

[0013] (5) After the ultrasonic treatment, add 30 to 33 parts of ethanol, stir evenly, and filter using an industrial filter;

[0014] (6) Take the filtrate, add 40-45 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter;

[0015] (7) Take the precipitated part and dry it in an oven at 58-63°C to obtain lignin A.

[0016] Furthermore, in step (4), the frequency of the ultrasonic treatment is 60 to 100W.

[0017] In a second aspect, the present invention also provides a method for preparing a woodworking adhesive.

[0018] The beneficial effects of the present invention are:

[0019] 1) The present invention uses disposable chopsticks as the raw material for obtaining lignin, which can save wood resources, create new economic value and social impact, and realize the recycling of resources;

[0020] 2) The present invention uses ultrasound to treat the semi-finished lignin product. Under the action of ultrasound at a certain temperature and power, the LCC structure can be quickly broken, the aromatic ether bond can be broken, and the phenolic hydroxyl content, extraction rate and relative purity of the lignin can be increased, thereby obtaining highly active lignin;

[0021] 3) The present invention applies lignin to woodworking adhesives. On the one hand, lignin can adjust the shrinkage rate during the curing process of the colloid, reduce the difference in thermal expansion coefficients between the adhesive and the adhesive, and prevent crack extension; on the other hand, the woodworking adhesive will soften during the hot pressing process, and the softened lignin can penetrate and fill the intercellular pores such as the vessels of the wood cell wall to form a physical bond; the highly active lignin will undergo in-situ self-crosslinking and its crosslinking reaction with the native lignin in the plant cell wall to form a chemical bond at the interface of the board. The synergistic effect of the two can have a good reinforcement effect on the adhesive. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail in combination with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The invention provides a woodworking adhesive. The woodworking adhesive comprises, by weight, 58 to 62 parts of silicone-acrylic emulsion, 12 to 14 parts of VAE emulsion, 18 to 22 parts of lignin A, 1 to 3 parts of zirconium acetate, 1 to 3 parts of silane coupling agent, 1 to 2 parts of defoamer, and 2 to 3 parts of thickener.

[0024] The lignin A is prepared by the following method, in parts by weight:

[0025] (1) using a garden grinder to crush the disposable chopsticks into particles, and using a grinder to grind the particles into wood powder with a particle size of 0.02 to 10 μm, preferably 0.5 to 1.5 μm;

[0026] (2) mixing choline chloride and oxalic acid hexahydrate in a molar ratio of 1:1 to 1.2, stirring and reacting at 90 to 110° C. for 1.5 to 2.5 hours to prepare a transparent and uniform low eutectic solvent;

[0027] (3) Weigh 18 to 24 parts of a deep eutectic solvent into a reaction kettle, add 5 to 7 parts of wood powder, heat and stir at 120 to 140° C. for 1 to 2 hours to obtain a solution a;

[0028] (4) then placing solution a in a water bath and subjecting it to ultrasonic treatment at 70-90° C. for 0.5-1.5 h;

[0029] (5) After the ultrasonic treatment, add 30 to 33 parts of ethanol, stir evenly, and filter using an industrial filter;

[0030] (6) Take the filtrate, add 40-45 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter;

[0031] (7) Take the precipitated part and dry it in an oven at 58-63°C to obtain lignin A.

[0032] The frequency of the ultrasonic treatment is 60-100W.

[0033] The present invention also provides a method for preparing the woodworking adhesive, which comprises the following steps, measured in parts by weight:

[0034] (a) Add 58-62 parts of silicone-acrylic emulsion and 12-14 parts of VAE emulsion into a stirring tank and stir for 0.4-0.6 hours;

[0035] (b) then adding 18 to 22 parts of lignin A and stirring for 0.4 to 0.6 hours;

[0036] (c) adding 1 to 3 parts of zirconium acetate, 1 to 3 parts of silane coupling agent, 1 to 2 parts of defoaming agent and 2 to 3 parts of thickener, stirring for 0.3 to 0.6 hours, and discharging the material to obtain a woodworking adhesive.

[0037] Example 1

[0038] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0039] (1) Preparation of lignin A1:

[0040] (1.1) Use a garden grinder to crush disposable chopsticks into particles, and use a grinder to grind the particles into wood powder with a particle size of 0.02 to 10 μm.

[0041] (1.2) Choline chloride and oxalic acid hexahydrate were mixed in a molar ratio of 1:1, and stirred at 100° C. for 2 h to prepare a transparent and uniform low eutectic solvent.

[0042] (1.3) Weigh 20 parts of a low eutectic solvent into a reaction kettle, add 6 parts of wood powder, heat and stir at 130°C for 1.5 hours to obtain solution a.

[0043] (1.4) Solution a was then placed in a water bath and subjected to ultrasonic treatment at 70°C for 1 h with a power of 60 W.

[0044] (1.5) After the ultrasonic treatment, add 32 parts of ethanol, stir evenly and filter using an industrial filter.

[0045] (1.6) Take the filtrate, add 43 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter.

[0046] (1.7) Take the precipitated part and dry it in an oven at 60°C to obtain lignin A1.

[0047] (2) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin A1, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0048] (3) Add silicone-acrylic emulsion and VAE emulsion into the stirring tank and stir for 1 hour.

[0049] (4) Slowly add lignin A1 and stir for 30 minutes.

[0050] (5) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0051] (6) Stop stirring and take out the product to obtain the woodworking adhesive.

[0052] Example 2

[0053] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0054] (1) Preparation of lignin A2:

[0055] (1.1) Use a garden grinder to crush the disposable chopsticks into particles, and use a grinder to grind the particles into wood powder with a particle size of 0.02-10 μm.

[0056] (1.2) Choline chloride and oxalic acid hexahydrate were mixed in a molar ratio of 1:1, and stirred at 100° C. for 2 h to prepare a transparent and uniform low eutectic solvent.

[0057] (1.3) Weigh 20 parts of a low eutectic solvent into a reaction kettle, add 6 parts of wood powder, heat and stir at 130°C for 1.5 hours to obtain solution a.

[0058] (1.4) Solution a was then placed in a water bath and subjected to ultrasonic treatment at 70°C for 1 h with a power of 80 W.

[0059] (1.5) After the ultrasonic treatment, add 32 parts of ethanol, stir evenly and filter using an industrial filter.

[0060] (1.6) Take the filtrate, add 43 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter.

[0061] (1.7) Take the precipitated part and dry it in an oven at 60°C to obtain lignin A2.

[0062] (2) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin A2, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0063] (3) Add silicone-acrylic emulsion and VAE emulsion into the stirring tank and stir for 1 hour.

[0064] (4) Slowly add lignin A2 and stir for 30 minutes.

[0065] (5) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0066] (6) Stop stirring and take out the product to obtain the woodworking adhesive.

[0067] Example 3

[0068] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0069] (1) Preparation of lignin A3:

[0070] (1.1) Use a garden grinder to crush the disposable chopsticks into particles, and use a grinder to grind the particles into wood powder with a particle size of 0.02-10 μm.

[0071] (1.2) Choline chloride and oxalic acid hexahydrate were mixed in a molar ratio of 1:1, and stirred at 100° C. for 2 h to prepare a transparent and uniform low eutectic solvent.

[0072] (1.3) Weigh 20 parts of a low eutectic solvent into a reaction kettle, add 6 parts of wood powder, heat and stir at 130°C for 1.5 hours to obtain solution a.

[0073] (1.4) Solution a was then placed in a water bath and subjected to ultrasonic treatment at 70°C for 1 h with a power of 100 W.

[0074] (1.5) After the ultrasonic treatment, add 32 parts of ethanol, stir evenly and filter using an industrial filter.

[0075] (1.6) Take the filtrate, add 43 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter.

[0076] (1.7) Take the precipitated part and dry it in an oven at 60°C to obtain lignin A3.

[0077] (2) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin A3, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0078] (3) Add silicone-acrylic emulsion and VAE emulsion into the stirring tank and stir for 1 hour.

[0079] (4) Slowly add lignin A3 and stir for 30 minutes.

[0080] (5) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0081] (6) Stop stirring and take out the product to obtain the woodworking adhesive.

[0082] Example 4

[0083] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0084] (1) Preparation of lignin A4:

[0085] (1.1) Use a garden grinder to crush the disposable chopsticks into particles, and use a grinder to grind the particles into wood powder with a particle size of 0.02-10 μm.

[0086] (1.2) Choline chloride and oxalic acid hexahydrate were mixed in a molar ratio of 1:1, and stirred at 100° C. for 2 h to prepare a transparent and uniform low eutectic solvent.

[0087] (1.3) Weigh 20 parts of a low eutectic solvent into a reaction kettle, add 6 parts of wood powder, heat and stir at 130°C for 1.5 hours to obtain solution a.

[0088] (1.4) Solution a was then placed in a water bath and subjected to ultrasonic treatment at 80°C for 1 h with a power of 60 W.

[0089] (1.5) After the ultrasonic treatment, add 32 parts of ethanol, stir evenly and filter using an industrial filter.

[0090] (1.6) Take the filtrate, add 43 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter.

[0091] (1.7) Take the precipitated part and dry it in an oven at 60°C to obtain lignin A4.

[0092] (2) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin A4, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0093] (3) Add silicone-acrylic emulsion and VAE emulsion into the stirring tank and stir for 1 hour.

[0094] (4) Slowly add lignin A4 and stir for 30 minutes.

[0095] (5) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0096] (6) Stop stirring and take out the product to obtain the woodworking adhesive.

[0097] Example 5

[0098] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0099] (1) Preparation of lignin A5:

[0100] (1.1) Use a garden grinder to crush the disposable chopsticks into particles, and use a grinder to grind the particles into wood powder with a particle size of 0.02-10 μm.

[0101] (1.2) Choline chloride and oxalic acid hexahydrate were mixed in a molar ratio of 1:1, and stirred at 100° C. for 2 h to prepare a transparent and uniform low eutectic solvent.

[0102] (1.3) Weigh 20 parts of a low eutectic solvent into a reaction kettle, add 6 parts of wood powder, heat and stir at 130°C for 1.5 hours to obtain solution a.

[0103] (1.4) Solution a was then placed in a water bath and subjected to ultrasonic treatment at 80°C for 1 h with a power of 80 W.

[0104] (1.5) After the ultrasonic treatment, add 32 parts of ethanol, stir evenly and filter using an industrial filter.

[0105] (1.6) Take the filtrate, add 43 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter.

[0106] (1.7) Take the precipitated part and dry it in an oven at 60°C to obtain lignin A5.

[0107] (2) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin A5, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0108] (3) Add silicone-acrylic emulsion and VAE emulsion into the stirring tank and stir for 1 hour.

[0109] (4) Slowly add lignin A5 and stir for 30 minutes.

[0110] (5) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0111] (6) Stop stirring and take out the product to obtain the woodworking adhesive.

[0112] Example 6

[0113] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0114] (1) Preparation of lignin A6:

[0115] (1.1) Use a garden grinder to crush the disposable chopsticks into particles, and use a grinder to grind the particles into wood powder with a particle size of 0.02-10 μm.

[0116] (1.2) Choline chloride and oxalic acid hexahydrate were mixed in a molar ratio of 1:1, and stirred at 100° C. for 2 h to prepare a transparent and uniform low eutectic solvent.

[0117] (1.3) Weigh 20 parts of a low eutectic solvent into a reaction kettle, add 6 parts of wood powder, heat and stir at 130°C for 1.5 hours to obtain solution a.

[0118] (1.4) Solution a was then placed in a water bath and subjected to ultrasonic treatment at 80°C for 1 h with a power of 100 W.

[0119] (1.5) After the ultrasonic treatment, add 32 parts of ethanol, stir evenly and filter using an industrial filter.

[0120] (1.6) Take the filtrate, add 43 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter.

[0121] (1.7) Take the precipitated part and dry it in an oven at 60°C to obtain lignin A6.

[0122] (2) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin A6, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0123] (3) Add silicone-acrylic emulsion and VAE emulsion into the stirring tank and stir for 1 hour.

[0124] (4) Slowly add lignin A6 and stir for 30 minutes.

[0125] (5) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0126] (6) Stop stirring and take out the product to obtain the woodworking adhesive.

[0127] Example 7

[0128] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0129] (1) Preparation of lignin A7:

[0130] (1.1) Use a garden grinder to crush the disposable chopsticks into particles, and use a grinder to grind the particles into wood powder with a particle size of 0.02-10 μm.

[0131] (1.2) Choline chloride and oxalic acid hexahydrate were mixed in a molar ratio of 1:1, and stirred at 100° C. for 2 h to prepare a transparent and uniform low eutectic solvent.

[0132] (1.3) Weigh 20 parts of a low eutectic solvent into a reaction kettle, add 6 parts of wood powder, heat and stir at 130°C for 1.5 hours to obtain solution a.

[0133] (1.4) Solution a was then placed in a water bath and subjected to ultrasonic treatment at 90 °C for 1 h with a power of 60 W.

[0134] (1.5) After the ultrasonic treatment, add 32 parts of ethanol, stir evenly and filter using an industrial filter.

[0135] (1.6) Take the filtrate, add 43 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter.

[0136] (1.7) Take the precipitated part and dry it in an oven at 60°C to obtain lignin A7.

[0137] (2) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin A7, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0138] (3) Add silicone-acrylic emulsion and VAE emulsion into the stirring tank and stir for 1 hour.

[0139] (4) Slowly add lignin A7 and stir for 30 minutes.

[0140] (5) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0141] (6) Stop stirring and take out the product to obtain the woodworking adhesive.

[0142] Example 8

[0143] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0144] (1) Preparation of lignin A8:

[0145] (1.1) Use a garden grinder to crush the disposable chopsticks into particles, and use a grinder to grind the particles into wood powder with a particle size of 0.02-10 μm.

[0146] (1.2) Choline chloride and oxalic acid hexahydrate were mixed in a molar ratio of 1:1, and stirred at 100° C. for 2 h to prepare a transparent and uniform low eutectic solvent.

[0147] (1.3) Weigh 20 parts of a low eutectic solvent into a reaction kettle, add 6 parts of wood powder, heat and stir at 130°C for 1.5 hours to obtain solution a.

[0148] (1.4) Solution a was then placed in a water bath and subjected to ultrasonic treatment at 90°C for 1 h with a power of 80 W.

[0149] (1.5) After the ultrasonic treatment, add 32 parts of ethanol, stir evenly and filter using an industrial filter.

[0150] (1.6) Take the filtrate, add 43 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter.

[0151] (1.7) Take the precipitated part and dry it in an oven at 60°C to obtain lignin A8.

[0152] (2) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin A8, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0153] (3) Add silicone-acrylic emulsion and VAE emulsion into the stirring tank and stir for 1 hour.

[0154] (4) Slowly add lignin A8 and stir for 30 minutes.

[0155] (5) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0156] (6) Stop stirring and take out the product to obtain the woodworking adhesive.

[0157] Example 9

[0158] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0159] (1) Preparation of lignin A9:

[0160] (1.1) Use a garden grinder to crush the disposable chopsticks into particles, and use a grinder to grind the particles into wood powder with a particle size of 0.02-10 μm.

[0161] (1.2) Choline chloride and oxalic acid hexahydrate were mixed in a molar ratio of 1:1, and stirred at 100° C. for 2 h to prepare a transparent and uniform low eutectic solvent.

[0162] (1.3) Weigh 20 parts of a low eutectic solvent into a reaction kettle, add 6 parts of wood powder, heat and stir at 130°C for 1.5 hours to obtain solution a.

[0163] (1.4) Solution a was then placed in a water bath and subjected to ultrasonic treatment at 90°C for 1 h with a power of 100 W.

[0164] (1.5) After the ultrasonic treatment, add 32 parts of ethanol, stir evenly and filter using an industrial filter.

[0165] (1.6) Take the filtrate, add 43 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter.

[0166] (1.7) Take the precipitated part and dry it in an oven at 60°C to obtain lignin A9.

[0167] (2) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin A9, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0168] (3) Add silicone-acrylic emulsion and VAE emulsion into the stirring tank and stir for 1 hour.

[0169] (4) Slowly add lignin A9 and stir for 30 minutes.

[0170] (5) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0171] (6) Stop stirring and take out the product to obtain the woodworking adhesive.

[0172] In order to select the best process conditions, the woodworking adhesives prepared in Examples 1 to 9 were subjected to a Class II water resistance test for plywood, and the test substrate was a poplar board in the standard test method for plywood. The test results are shown in Table 1.

[0173] Table 1: Test results of woodworking adhesives prepared in Examples 1 to 9

[0174]

[0175] From the test results, the lignin A5 produced by using an ultrasonic temperature of 80°C and an ultrasonic power of 80W has the best performance. Lignin sulfate is used as a substitute, and the comparative examples and embodiments are as follows:

[0176] Comparative Example 1

[0177] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0178] (1) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 0 parts of lignin, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0179] (2) Add silicone-acrylic emulsion and VAE emulsion into a stirring tank and stir for 1 hour.

[0180] (3) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0181] (4) Stop stirring and take out the product to obtain the woodworking adhesive.

[0182] Comparative Example 2

[0183] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0184] (1) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 20 parts of lignin sulfate, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0185] (2) Add silicone-acrylic emulsion and VAE emulsion into a stirring tank and stir for 1 hour.

[0186] (3) Slowly add lignin sulfate and stir for 30 minutes.

[0187] (4) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0188] (5) Stop stirring and take out the product to obtain the woodworking adhesive.

[0189] Example 10

[0190] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0191] (1) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 15 parts of lignin sulfate, 5 parts of lignin A5 prepared in Example 5, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0192] (2) Add silicone-acrylic emulsion and VAE emulsion into a stirring tank and stir for 1 hour.

[0193] (3) Slowly add lignin sulfate and lignin A5 and stir for 30 minutes.

[0194] (4) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0195] (5) Stop stirring and take out the product to obtain the woodworking adhesive.

[0196] Embodiment 11

[0197] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0198] (1) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 10 parts of lignin sulfate, 10 parts of lignin A5 prepared in Example 5, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0199] (2) Add silicone-acrylic emulsion and VAE emulsion into a stirring tank and stir for 1 hour.

[0200] (3) Slowly add lignin sulfate and lignin A5 and stir for 30 minutes.

[0201] (4) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0202] (5) Stop stirring and take out the product to obtain the woodworking adhesive.

[0203] Example 12

[0204] A preparation method of a woodworking adhesive, in parts by weight, the preparation process and formula thereof are as follows:

[0205] (1) Weigh 60 parts of silicone-acrylic emulsion, 13 parts of VAE emulsion, 5 parts of lignin sulfate, 15 parts of lignin A5 prepared in Example 5, 2 parts of zirconium acetate, 1 part of silane coupling agent, 1 part of defoamer and 3 parts of thickener.

[0206] (2) Add silicone-acrylic emulsion and VAE emulsion into a stirring tank and stir for 1 hour.

[0207] (3) Slowly add lignin sulfate and lignin A5 and stir for 30 minutes.

[0208] (4) Add zirconium acetate, silane coupling agent, defoamer and thickener and stir for 15 minutes.

[0209] (5) Stop stirring and take out the product to obtain the woodworking adhesive.

[0210] In order to compare the change of plywood strength with the amount of lignin A5 and whether the present invention has obvious advantages over competing products, comparative examples 1-2, examples 5, and examples 10-12 were tested for Class I and Class II plywood, and the test substrate was a poplar board in the standard test method for plywood. The test results are shown in Table 2.

[0211] Table 2: Test results of woodworking adhesives prepared in Comparative Examples 1-2, Example 5, and Examples 10-12

[0212]

[0213] From the test results, it can be seen that with the increase in the amount of lignin A5, the strength of Class I and Class II plywood is significantly improved. When the filler part is all made of lignin A5, the strength and wood breakage rate are the highest; in the same group test with competing products, it is found that the strength of competing products is weaker than the lignin wood glue prepared by the present invention. In summary, the use of lignin prepared by the present invention can significantly improve the bonding strength and wood breakage rate of Class I and Class II adhesives, and the lignin wood glue prepared by it has obvious advantages over competing products.

[0214] Taking the test method of Class II plywood as a reference and the type of substrate as the only variable, the bonding strength tests were carried out on poplar boards, oak boards, and birch boards. The test results are shown in Table 3.

[0215] Table 3: Bonding strength test results of woodworking adhesives prepared in Comparative Examples 1-2 and Example 5

[0216]

[0217] From the data of Example 5, the plywood made with oak and birch boards as the base material has a slightly lower bonding strength than poplar, but has good bonding performance. Compared with the comparative examples, the bonding strength of Example 5 on poplar, oak and birch is significantly better than that of Comparative Examples 1 and 2. Therefore, the adhesive prepared by the present invention includes but is not limited to being applied to furniture, particleboard, flooring and other fields with poplar, oak and birch boards as the base material.

[0218] It can be concluded that the present invention recycles lignin from discarded disposable chopsticks, and further prepares the adhesive in a mature process, and the adhesive finally prepared has excellent performance and can meet the glue standards of the woodworking industry. That is, through the technology provided by the present invention, a large number of discarded disposable chopsticks can be recycled to prevent disposable chopsticks from polluting the environment, which can effectively protect the environment and reduce the consumption of forest resources. Discarded disposable chopsticks are also a low-cost source of raw materials for enterprises, which can effectively reduce the glue production cost of adhesive enterprises, improve the market competitiveness of the woodworking adhesive of the system, and then reduce the cost of glue for customers in the entire woodworking industry, and finally benefit consumers and promote the development of market consumption.

[0219] Through a specific process, disposable chopsticks are used to extract lignin, and then the adhesive is prepared through a formula. The performance of the final prepared adhesive is significantly better than the commonly used woodworking adhesives on the market. It proves that the lignin extracted from disposable chopsticks has excellent performance and can be used in woodworking adhesives to significantly improve the performance of the adhesive. It can firmly bond woodworking products. It meets the market demand for high-performance adhesives, provides customers with better quality woodworking adhesives, and then provides end consumers with better performance products.

[0220] Therefore, the present invention is beneficial to environmental protection, the economic benefits of enterprises and the quality requirements of society for products, and helps to achieve balanced development of the environment, society and economy.

[0221] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A woodworking adhesive, It is characterized in that The woodworking adhesive comprises, by weight, 58 to 62 parts of silicone-acrylic emulsion, 12 to 14 parts of VAE emulsion, 18 to 22 parts of lignin A, 1 to 3 parts of zirconium acetate, 1 to 3 parts of silane coupling agent, 1 to 2 parts of defoamer, and 2 to 3 parts of thickener.

2. A woodworking adhesive according to claim 1, It is characterized in that The lignin A is prepared by the following method, in parts by weight: (1) using a garden grinder to crush the disposable chopsticks into particles, and using a grinder to grind the particles into wood powder with a particle size of 0.02 to 10 μm, preferably 0.5 to 1.5 μm; (2) mixing choline chloride and oxalic acid hexahydrate in a molar ratio of 1:1 to 1.2, stirring and reacting at 90 to 110° C. for 1.5 to 2.5 hours to prepare a transparent and uniform low eutectic solvent; (3) Weigh 18 to 24 parts of a deep eutectic solvent into a reaction kettle, add 5 to 7 parts of wood powder, heat and stir at 120 to 140° C. for 1 to 2 hours to obtain a solution a; (4) then placing solution a in a water bath and subjecting it to ultrasonic treatment at 70-90° C. for 0.5-1.5 h; (5) After the ultrasonic treatment, add 30 to 33 parts of ethanol, stir evenly, and filter using an industrial filter; (6) Take the filtrate, add 40-45 parts of water, stir evenly, let stand for 6 hours, and filter using an industrial filter; (7) Take the precipitated part and dry it in an oven at 58-63°C to obtain lignin A.

3. A woodworking adhesive according to claim 2, It is characterized in that In step (4), the frequency of the ultrasonic treatment is 60 to 100W.

4. A method for preparing the woodworking adhesive according to any one of claims 1 to 3, It is characterized in that By weight, the method comprises the following steps: (a) Add 58-62 parts of silicone-acrylic emulsion and 12-14 parts of VAE emulsion into a stirring tank and stir for 0.4-0.6 hours; (b) then adding 18 to 22 parts of lignin A and stirring for 0.4 to 0.6 hours; (c) adding 1 to 3 parts of zirconium acetate, 1 to 3 parts of silane coupling agent, 1 to 2 parts of defoaming agent and 2 to 3 parts of thickener, stirring for 0.3 to 0.6 hours, and discharging the material to obtain a woodworking adhesive.

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