A biomass polyester wood adhesive and preparation method thereof

Abstract

The present invention discloses a biomass polyester wood adhesive, including a biomass polyester wood adhesive molecular structure: a method for preparing a biomass polyester wood adhesive, wherein the raw materials for preparing the biomass polyester wood adhesive include a highly branched polyacid and a biomass polyol; the preparation process of the biomass polyester wood adhesive specifically includes: step 1, preparing the highly branched polyacid, wherein the highly branched polyacid is a pentabasic acid; step 2, preparing the biomass polyester wood adhesive from the biomass polyol and the highly branched polyacid, wherein the preparation method is a mixed reaction. The present invention combines maleic anhydride and xylitol to prepare a highly branched polyacid, and then prepares the biomass polyester wood adhesive with a polyol. The adhesive prepared by the present invention is a completely green and pollution-free material, which is harmless to the human body and has better performance than other adhesives in the prior art.

Description

Technical Field

[0001] The invention discloses a biomass polyester wood adhesive and a preparation method thereof, and relates to the technical field of adhesives, in particular to the technical field of a biomass polyester wood adhesive prepared from biomass highly branched polyacids and biomass polyols and a preparation method thereof. Background Art

[0002] The global wood adhesive market is expected to reach US$6.18 billion in 2025. As the main product in the wood industry, wood-based panels are of great significance to improving wood utilization and saving wood resources. Formaldehyde-based resins in the prior art, such as urea-formaldehyde resins, melamine-formaldehyde resins, phenolic resins, etc., account for about 90% of wood adhesives, which is related to their good bonding properties, water resistance and weather resistance. However, formaldehyde-based wood adhesive materials will pollute the environment both during the manufacturing process and during use, affecting the health of relevant personnel. Compared with the former, formaldehyde-free wood adhesives are regarded as green and environmentally friendly wood adhesives, but most of the formaldehyde-free wood adhesives in the prior art have poor plywood performance. Summary of the invention

[0003] The object of the present invention is to provide a biomass polyester wood adhesive and a preparation method thereof, so as to solve the problem of poor performance of plywood using formaldehyde-free wood adhesive in the prior art.

[0004] In order to achieve the above technical objectives and the above technical effects, the invention is implemented through the following technical solutions:

[0005] A biomass polyester wood adhesive and a preparation method thereof, comprising: the molecular structure of the biomass polyester wood adhesive is:

[0006] Another object of the present invention is to disclose a method for preparing a biomass polyester wood adhesive, wherein the raw materials for preparing the biomass polyester wood adhesive include highly branched polyacids and biomass polyols;

[0007] The preparation process of the biomass polyester wood adhesive specifically includes:

[0008] Step 1: preparing the highly branched polyacid,

[0009] The highly branched polybasic acid is a pentabasic acid;

[0010] Step 2: preparing the biomass polyester wood adhesive from the biomass polyol and the highly branched polyacid,

[0011] The preparation method is a mixing reaction.

[0012] Furthermore, the specific preparation method of the highly branched polyacid is to mix maleic anhydride and xylitol (molar ratio 5:1) and add them into a reactor, raise the temperature to 110°C and stir continuously for 1 hour to obtain the highly branched polyacid.

[0013] Furthermore, the molecular structure of the highly branched polyacid is: .

[0014] Furthermore, the biomass polyol is any one of polyols such as ethylene glycol, glycerol, erythritol, xylitol, mannitol, sorbitol, and maltitol.

[0015] Furthermore, the step 2 specifically includes:

[0016] Step 201, mixing the highly branched polyacid and biomass polyol obtained in step 1 at a molar ratio of 1:0.6-1, placing in a reactor for reaction for 0.5-2h;

[0017] Step 202: After the reaction is completed, the product is cooled to room temperature, and deionized water is added according to the solid content of 40-60% to completely dissolve it.

[0018] Furthermore, the molecular reaction process of the biomass polyester wood adhesive is specifically as follows:

[0019]

[0020]

[0021]

[0022] Preparation of highly branched polyacids

[0023]

[0024]

[0025]

[0026]

[0027] Preparation of Biomass Polyesters

[0028] Another object of the present invention is to disclose a three-layer plywood prepared by using the biomass polyester wood adhesive, characterized in that the specific steps of preparation include:

[0029] Step A, drying,

[0030] The veneer is dried to a moisture content of less than 5-10%;

[0031] Step B, sizing,

[0032] Double-sided adhesive coating;

[0033] Step C, assembly,

[0034] Assemble the blanks based on vertical grain method;

[0035] Step D, hot pressing,

[0036] Hot pressing is performed at a temperature of 100-300°C and a pressure of 0.5-2 MPa for 4-8 minutes.

[0037] Further, the veneer is dried to a moisture content of less than 9%;

[0038] The amount of glue applied on one side of the double-sided coating is 150 g / m 2 , no aging required;

[0039] The hot pressing parameters are as follows: hot pressing temperature is 220°C, hot pressing pressure is 1 MPa, and hot pressing time is 5 min;

[0040] The dry shear strength of the specimen with dimensions of (100 mm × 25 mm) and an adhesive layer area of ​​25 mm × 25 mm is 2.26 MPa. Beneficial Effects

[0041] The present invention combines maleic anhydride and xylitol to prepare a highly branched polyacid, and then prepares the biomass polyester wood adhesive with polyol. The adhesive prepared by the present invention is a completely green and pollution-free material, and is harmless to the human body compared to other adhesives in the prior art. It can be found that the dry shear strength of the three-layer plywood prepared by the adhesive of the present invention can reach 2.26 Mpa, which is better than other formaldehyde-free wood adhesives.

[0042] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a diagram of a method for preparing a biomass polyester wood adhesive according to an embodiment of the present invention;

[0044] Figure 2 This is a diagram of a method for preparing a three-layer plywood according to an embodiment of the present invention; DETAILED DESCRIPTION

[0045] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the present invention will be described in detail with reference to the accompanying drawings. Example 1

[0046] This embodiment provides a method for preparing a biomass highly branched polyacid-biomass polyol wood adhesive, which is prepared according to the following method:

[0047] Step 1, weigh 12.25g of maleic anhydride and 3.8g of xylitol at room temperature, mix and react at 110°C with continuous stirring for 1h;

[0048] Step 2: Mix the highly branched polyacid prepared above and xylitol (2.28 g), and react with continuous stirring at 140° C. for 1 h. After the reaction, cool to room temperature, and add 9.82 g of deionized water to completely dissolve the mixture. Example 2

[0049] This embodiment provides a method for preparing a biomass highly branched polyacid-biomass polyol wood adhesive, which is prepared according to the following method:

[0050] Step 1, weigh 12.25g of maleic anhydride and 3.8g of xylitol at room temperature, mix and react at 110°C with continuous stirring for 1h;

[0051] Step 2: Mix the highly branched polyacid prepared above and erythritol (3.04 g), and react with continuous stirring at 140° C. for 1 h. After the reaction, cool to room temperature, and add 10.03 g of deionized water to completely dissolve the mixture. Example 3

[0052] This embodiment provides a method for preparing a biomass highly branched polyacid-biomass polyol wood adhesive, which is prepared according to the following method:

[0053] Step 1, weigh 12.25g of maleic anhydride and 3.8g of xylitol at room temperature, mix and react at 110°C with continuous stirring for 1h;

[0054] Step 2: Mix the highly branched polyacid prepared above and mannitol (3.8 g), stir and react at 140° C. for 1 h, cool to room temperature after the reaction, and add 10.23 g of deionized water to completely dissolve the mixture. Example 4

[0055] This embodiment provides a method for preparing a biomass highly branched polyacid-biomass polyol wood adhesive, which is prepared according to the following method:

[0056] Step 1, weigh 12.25g of maleic anhydride and 3.8g of xylitol at room temperature, mix and react at 110°C with continuous stirring for 1h;

[0057] Step 2: Mix the highly branched polyacid prepared above and xylitol (3.8 g), and react at 140° C. with continuous stirring for 0.5 h. After the reaction, cool to room temperature, and add 10.23 g of deionized water to completely dissolve the mixture. Example 5

[0058] This embodiment provides a method for preparing a biomass highly branched polyacid-biomass polyol wood adhesive, which is prepared according to the following method:

[0059] Step 1, weigh 12.25g of maleic anhydride and 3.8g of xylitol at room temperature, mix and react at 110°C with continuous stirring for 1h;

[0060] Step 2: Mix the highly branched polyacid prepared above and sorbitol (3.8 g), stir and react at 140° C. for 2 h, cool to room temperature after the reaction, and add 10.23 g of deionized water to completely dissolve the mixture. Example 6

[0061] This embodiment provides a method for preparing a biomass highly branched polyacid-biomass polyol wood adhesive, which is prepared according to the following method:

[0062] Step 1, weigh 12.25g of maleic anhydride and 3.8g of xylitol at room temperature, mix and react at 110°C with continuous stirring for 1h;

[0063] Step 2: Mix the highly branched polyacid prepared above and maltitol (3.8 g), stir and react at 140° C. for 1 h, cool to room temperature after the reaction, and add 10.23 g of deionized water to completely dissolve the mixture.

[0064] In this embodiment, the above-mentioned adhesive is used to prepare a plywood heat treatment process, and the steps include:

[0065] Step A, drying,

[0066] The veneer is dried to a moisture content of less than 5-10%;

[0067] Step B, sizing,

[0068] Double-sided adhesive coating;

[0069] Step C, assembly,

[0070] Assemble the blanks based on vertical grain method;

[0071] Step D, hot pressing,

[0072] Hot pressing is performed at a temperature of 100-300°C and a pressure of 0.5-2MPa for 4-8 minutes.

[0073] In this embodiment, the specific parameters are: the pressing temperature is 210° C., the hot pressing pressure is 1 MPa, and the hot pressing time is 5 min. Example 7

[0074] This embodiment provides a method for preparing a biomass highly branched polyacid-biomass polyol wood adhesive, which is prepared according to the following method:

[0075] Step 1, weigh 12.25g of maleic anhydride and 3.8g of xylitol at room temperature, mix and react at 110°C with continuous stirring for 1h;

[0076] Step 2: Mix the highly branched polyacid prepared above and glycerol (3.8 g), stir and react at 140° C. for 1 h, cool to room temperature after the reaction, and add 10.23 g of deionized water to completely dissolve the mixture.

[0077] Combined with the preparation method of the adhesive board in Example 6, in this embodiment, the hot pressing temperature of the plywood is 220° C., the hot pressing pressure is 1 MPa, and the hot pressing time is 5 min.

[0078] The adhesive and adhesive board prepared by combining the parameters of Examples 1-6 and this example, the bonding strength test is carried out according to the relevant requirements of the national standard GB / T17657-2013. First, the samples are sawed into the same size (100 mm×25 mm), and the grooves are cut. The area of ​​the adhesive layer is 25 mm×25 mm. They are immersed in a water bath at 63±3 ℃ and 93±3 ℃ for 3 hours respectively, and then placed at room temperature for ten minutes after being taken out, and then the bonding strength test is carried out using an electronic universal mechanical testing machine. The test results are shown in Table 1:

[0079] Table 1 Properties of plywood prepared with different adhesives

[0080] Group No. Dry shear strength / MPa 3h hot water (63℃) soaking wet strength / MPa 3h boiling water (93℃) soaking wet strength / MPa Example 1 2.06 1.07 1.12 Example 2 2.17 1.29 1.15 Example 3 1.99 1.42 1.37 Example 4 2.12 1.23 1.31 Example 5 2.06 1.49 1.32 Example 6 2.10 1.45 1.48 Example 7 2.26 1.57 1.51

[0081] The above is only part of the embodiment of the application, and does not limit the application in any form. Any simple modification, equivalent change and modification made to the above embodiment still falls within the scope of protection of the technical solution of the application.

Claims

1. A method for preparing a biomass polyester wood adhesive, characterized in that: The raw materials for preparing the biomass polyester wood adhesive include highly branched polyacids and biomass polyols; The preparation process of the biomass polyester wood adhesive specifically includes: Step 1: preparing the highly branched polyacid, The highly branched polybasic acid is a pentabasic acid; Step 2: preparing the biomass polyester wood adhesive from the biomass polyol and the highly branched polyacid, The biomass polyester wood adhesive is prepared by a mixing reaction; The specific preparation method of the highly branched polyacid is as follows: maleic anhydride and xylitol are mixed and added into a reactor, and the mixture is heated to 110° C. and stirred continuously for 1 hour to obtain the highly branched polyacid; The molar ratio of maleic anhydride to xylitol is 5:1; The biomass polyol is xylitol; The step 2 specifically includes: Step 201, mixing the highly branched polyacid and biomass polyol obtained in step 1 at a molar ratio of 1:0.6-1, placing in a reactor for reaction for 0.5-2h; Step 202: After the reaction is completed, the product is cooled to room temperature, and deionized water is added according to the solid content of 40-60% to completely dissolve it.

2. The method for preparing a biomass polyester wood adhesive according to claim 1, characterized in that: The molecular structure of the highly branched polyacid is: .

3. A biomass polyester wood adhesive prepared by the method for preparing the biomass polyester wood adhesive according to any one of claims 1 to 2.

4. A biomass polyester wood adhesive according to claim 3, characterized in that: The biomass polyester wood adhesive is used for preparing three-layer plywood.

5. A three-layer plywood prepared by a biomass polyester wood adhesive according to claim 4, characterized in that: The specific steps of preparation include: Step A, drying, The veneer is dried to a moisture content of less than 5-10%; Step B, sizing, Double-sided adhesive coating; Step C, assembly, Assemble the blanks based on vertical grain method; Step D, hot pressing, Hot pressing is performed at a temperature of 100-300°C and a pressure of 0.5-2MPa for 4-8 minutes.

6. A three-layer plywood according to claim 5, characterized in that: The veneer is dried to a moisture content of less than 9%; The amount of glue applied on one side of the double-sided coating is 150 g / m 2 , no aging required; The hot pressing parameters are as follows: hot pressing temperature is 220°C, hot pressing pressure is 1 MPa, and hot pressing time is 5 min; The dry shear strength of the specimen with a size of 100 mm × 25 mm and an adhesive layer area of ​​25 mm × 25 mm is 2.26 MPa.

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