High-strength starch adhesive for artificial boards, preparation method and use method thereof

Abstract

The present invention relates to a high-strength starch adhesive for artificial boards, a preparation method and a use method thereof, and belongs to the technical field of starch adhesives. In order to solve the problem that the water resistance and bonding strength of traditional starch adhesives cannot meet the production requirements of artificial boards, the present invention provides a high-strength starch adhesive for artificial boards, a preparation method and a use method thereof. The components of the high-strength starch adhesive for artificial boards of the present invention include prefabricated materials, dry-base starch and isocyanate; wherein the components of the prefabricated materials include oxidized starch, gelatin, a cross-linking agent and distilled water. The high-strength starch adhesive for artificial boards prepared by the present invention is prepared by chemical cross-linking with renewable starch and gelatin as the main materials, and has the advantages of high bonding strength, good water resistance, no formaldehyde generation, and environmental friendliness. It meets the national requirements for Class II plywood and has broad market prospects in the field of artificial board manufacturing.

Description

Technical Field

[0001] The present invention belongs to the technical field of starch adhesives, and in particular relates to a high-strength starch adhesive for artificial boards, a preparation method thereof, and a use method thereof. Background Art

[0002] In modern furniture manufacturing, interior decoration, and construction, wood-based panels are widely used due to their excellent physical and mechanical properties, dimensional stability, and ease of processing. As a key material in the production of wood-based panels, the performance of adhesives directly impacts the quality and performance of the panels. To ensure that wood-based panels meet diverse operating conditions and environmental requirements, adhesives must meet requirements for bond strength, water resistance, and environmental friendliness.

[0003] Currently, the adhesives used in wood-based panel production are primarily "trialdehyde adhesives," namely urea-formaldehyde resins, phenol-formaldehyde resins, and melamine-formaldehyde resins. These adhesives release free formaldehyde during use, posing a threat to the environment and human health. Therefore, the development of environmentally friendly, formaldehyde-free adhesives is crucial for the healthy development of the wood-based panel industry.

[0004] Starch adhesives are made from starch through physical, chemical, or biological modification. As green and environmentally friendly adhesives, their research and application are expected to provide strong support for the environmentally friendly transformation of the wood-based panel industry. However, because starch backbones contain numerous hydrophilic hydroxyl groups and fail to form an effective network cross-linking structure after bonding, their water resistance and bonding strength are relatively weak. Therefore, traditional starch adhesives cannot meet the adhesive requirements of wood-based panel production. Summary of the Invention

[0005] In order to solve the problem that the water resistance and bonding strength of traditional starch adhesives cannot meet the production requirements of artificial boards, the present invention provides a high-strength starch adhesive for artificial boards, a preparation method and a use method thereof.

[0006] The technical solution of the present invention:

[0007] A high-strength starch adhesive for artificial panels comprises the following components in parts by mass: 100 parts of a prefabricated material, 30-70 parts of dry-base starch, and 10-30 parts of isocyanate; the prefabricated material comprises the following components in parts by mass: 60-100 parts of oxidized starch, 80-100 parts of gelatin, 10-30 parts of a cross-linking agent, and 600-1000 parts of distilled water.

[0008] Furthermore, the crosslinking agent is one or a combination of polyethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, long-chain alkyl glycidyl ether, neopentyl glycol diglycidyl ether, polypropylene oxide diglycidyl ether, glycerol diglycidyl ether or 1,4-butanediol glycidyl ether.

[0009] Furthermore, the isocyanate is one or a combination of polymethylene polyphenyl isocyanate, toluene diisocyanate TDI, isophorone diisocyanate IPDI, diphenylmethane diisocyanate MDI, dicyclohexylmethane diisocyanate HMDI, hexamethylene diisocyanate HDI or lysine diisocyanate.

[0010] A method for preparing a high-strength starch adhesive for artificial boards comprises the following steps:

[0011] Step 1: Prepare the prefabricated material: fully mix the oxidized starch, gelatin and distilled water, then add the cross-linking agent and continue the reaction for a certain period of time to obtain the prefabricated material;

[0012] Step 2: preparing starch adhesive: when using, the prefabricated material prepared in step 1, dry starch and isocyanate are mixed and stirred evenly according to parts by mass to obtain starch adhesive.

[0013] Furthermore, the thorough mixing and stirring in step 1 is performed at 60-80° C. for 30 minutes.

[0014] Furthermore, the continued reaction in step 1 is carried out at 60-80° C. for 2-4 hours.

[0015] A method for using a high-strength starch adhesive for artificial boards. When using, the starch adhesive is evenly applied on the wood veneer, and the amount of adhesive applied on one side of the board is 200-300g / m 2 , bonding is completed through pre-pressing and hot pressing.

[0016] Furthermore, the pre-pressing is performed for 30 minutes under a pressure of 2 to 5 MPa.

[0017] Furthermore, the hot pressing is performed at a temperature of 110 to 130° C. using a hot press and applying a pressure of 2 to 3 MPa for 10 minutes.

[0018] Furthermore, the method further includes placing the hot-pressed artificial board in an environment for 24 hours to eliminate internal stress.

[0019] Beneficial effects of the present invention:

[0020] The high-strength starch adhesive for artificial boards prepared by the present invention is prepared by chemical cross-linking with renewable starch and gelatin as the main materials. It has the advantages of high bonding strength, good water resistance, no formaldehyde generation, environmental friendliness, low cost, etc., meets the national requirements for Class II plywood, and has broad market prospects in the field of artificial board manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a photograph of the fracture surface of the plate after wet tensile testing of the high-strength starch adhesive prepared in Example 1;

[0022] Figure 2 This is a photograph of the fracture surface of the plate after wet tensile testing of the high-strength starch adhesive prepared in Example 5;

[0023] Figure 3 This is a photograph of the fracture surface of the board after the wet strength tensile test of the starch adhesive prepared in Comparative Example 1. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below with reference to the embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the scope of protection of the present invention. The process equipment or devices not specifically noted in the following examples are all conventional equipment or devices in the art. Unless otherwise specified, the raw materials used in the examples of the present invention can be obtained commercially; unless otherwise specified, the technical means used in the examples of the present invention are all conventional means well known to those skilled in the art.

[0025] Example 1

[0026] This embodiment provides a high-strength starch adhesive and uses it in the preparation of plywood.

[0027] The method for preparing a high-strength starch adhesive for artificial boards provided in this embodiment comprises the following steps:

[0028] Step 1: Prepare a prefabricated material: thoroughly mix 100 parts of oxidized starch, 80 parts of gelatin, and 800 parts of distilled water, stir in a 70°C water bath for 30 minutes, then add 15 parts of polyethylene glycol diglycidyl ether, and continue stirring and reacting at 75°C for 2 hours to obtain a prefabricated material;

[0029] Step 2: Prepare starch adhesive: When using, mix and stir 100 parts of the prefabricated material prepared in step 1, 50 parts of dry starch and 10 parts of polymethylene polyphenyl isocyanate to obtain starch adhesive.

[0030] The starch adhesive prepared in this example was used to prepare plywood, and the specific method was as follows:

[0031] Apply starch adhesive evenly on the wood veneer, with a single-sided adhesive amount of 240g / m 2 , pre-press at 3MPa for 30min, take out the plywood, place it in a hot press, and press it at 3MPa for 10min at a temperature of 120℃ to obtain the plywood.

[0032] Example 2

[0033] This embodiment provides a high-strength starch adhesive and uses it in the preparation of plywood.

[0034] The method for preparing a high-strength starch adhesive for artificial boards provided in this embodiment comprises the following steps:

[0035] Step 1: Prepare a prefabricated material: fully mix 100 parts of oxidized starch, 80 parts of gelatin, and 800 parts of distilled water, stir in a 70°C water bath for 30 minutes, add 15 parts of bisphenol A diglycidyl ether, and continue stirring and reacting at 80°C for 2 hours to obtain a prefabricated material;

[0036] Step 2: Prepare starch adhesive: When using, mix and stir 100 parts of the prefabricated material prepared in step 1, 50 parts of dry starch and 10 parts of polymethylene polyphenyl isocyanate to obtain starch adhesive.

[0037] The starch adhesive prepared in this example was used to prepare plywood, and the specific method was as follows:

[0038] Apply starch adhesive evenly on the wood veneer, with a single-sided adhesive amount of 240g / m 2 , pre-press at 3MPa for 30min, take out the plywood, place it in a hot press, and press it at 3MPa for 10min at a temperature of 120℃ to obtain the plywood.

[0039] Example 3

[0040] This embodiment provides a high-strength starch adhesive and uses it in the preparation of plywood.

[0041] The method for preparing a high-strength starch adhesive for artificial boards provided in this embodiment comprises the following steps:

[0042] Step 1: Prepare a prefabricated material: fully mix 100 parts of oxidized starch, 80 parts of gelatin and 800 parts of distilled water, stir in a 70°C water bath for 30 minutes, add 15 parts of alkyl glycidyl ether, and continue stirring and reacting at 70°C for 2 hours to obtain a prefabricated material;

[0043] Step 2: Prepare starch adhesive: When using, mix and stir 100 parts of the prefabricated material prepared in step 1, 50 parts of dry starch and 10 parts of polymethylene polyphenyl isocyanate to obtain starch adhesive.

[0044] The starch adhesive prepared in this example was used to prepare plywood, and the specific method was as follows:

[0045] Apply starch adhesive evenly on the wood veneer, with a single-sided adhesive amount of 240g / m 2, pre-press at 3MPa for 30min, take out the plywood, place it in a hot press, and press it at 3MPa for 10min at a temperature of 120℃ to obtain the plywood.

[0046] Example 4

[0047] This embodiment provides a high-strength starch adhesive and uses it in the preparation of plywood.

[0048] The method for preparing a high-strength starch adhesive for artificial boards provided in this embodiment comprises the following steps:

[0049] Step 1: Prepare a prefabricated material: thoroughly mix 100 parts of oxidized starch, 50 parts of gelatin, and 800 parts of distilled water, stir in a 75°C water bath for 30 minutes, then add 20 parts of alkyl glycidyl ether, and continue stirring and reacting at 75°C for 2 hours to obtain a prefabricated material;

[0050] Step 2: Prepare starch adhesive: When using, mix and stir 100 parts of the prefabricated material prepared in step 1, 50 parts of dry starch and 10 parts of polymethylene polyphenyl isocyanate to obtain starch adhesive.

[0051] The starch adhesive prepared in this example was used to prepare plywood, and the specific method was as follows:

[0052] Apply starch adhesive evenly on the wood veneer, with a single-sided adhesive amount of 240g / m 2 , pre-press at 3MPa for 30min, take out the plywood, place it in a hot press, and press it at 3MPa for 10min at a temperature of 120℃ to obtain the plywood.

[0053] Example 5

[0054] This embodiment provides a high-strength starch adhesive and uses it in the preparation of plywood.

[0055] The method for preparing a high-strength starch adhesive for artificial boards provided in this embodiment comprises the following steps:

[0056] Step 1: Prepare a prefabricated material: thoroughly mix 100 parts of oxidized starch, 80 parts of gelatin, and 800 parts of distilled water, stir in a 70°C water bath for 30 minutes, then add 20 parts of polyethylene glycol diglycidyl ether, and continue stirring and reacting at 75°C for 2 hours to obtain a prefabricated material;

[0057] Step 2: Prepare starch adhesive: When using, mix and stir 100 parts of the prefabricated material prepared in step 1, 50 parts of dry starch and 10 parts of polymethylene polyphenyl isocyanate to obtain starch adhesive.

[0058] The starch adhesive prepared in this example was used to prepare plywood, and the specific method was as follows:

[0059] Apply starch adhesive evenly on the wood veneer, with a single-sided adhesive amount of 240g / m 2 , pre-press at 3MPa for 30min, take out the plywood, place it in a hot press, and press it at 3MPa for 10min at a temperature of 120℃ to obtain the plywood.

[0060] Example 6

[0061] This embodiment provides a high-strength starch adhesive and uses it in the preparation of plywood.

[0062] The method for preparing a high-strength starch adhesive for artificial boards provided in this embodiment comprises the following steps:

[0063] Step 1: Prepare a prefabricated material: thoroughly mix 100 parts of oxidized starch, 80 parts of gelatin, and 800 parts of distilled water, stir in a 70°C water bath for 30 minutes, then add 15 parts of polyethylene glycol diglycidyl ether, and continue stirring and reacting at 75°C for 2 hours to obtain a prefabricated material;

[0064] Step 2: Prepare starch adhesive: When using, mix and stir 100 parts of the prefabricated material prepared in step 1, 70 parts of dry starch and 10 parts of polymethylene polyphenyl isocyanate to obtain starch adhesive.

[0065] The starch adhesive prepared in this example was used to prepare plywood, and the specific method was as follows:

[0066] Apply starch adhesive evenly on the wood veneer, with a single-sided adhesive amount of 240g / m 2 , pre-press at 3MPa for 30min, take out the plywood, place it in a hot press, and press it at 3MPa for 10min at a temperature of 120℃ to obtain the plywood.

[0067] Example 7

[0068] This embodiment provides a high-strength starch adhesive and uses it in the preparation of plywood.

[0069] The method for preparing a high-strength starch adhesive for artificial boards provided in this embodiment comprises the following steps:

[0070] Step 1: Prepare a prefabricated material: thoroughly mix 100 parts of oxidized starch, 80 parts of gelatin, and 800 parts of distilled water, stir in a 70°C water bath for 30 minutes, then add 15 parts of polyethylene glycol diglycidyl ether, and continue stirring and reacting at 75°C for 2 hours to obtain a prefabricated material;

[0071] Step 2: Prepare starch adhesive: When using, mix and stir 100 parts of the prefabricated material prepared in step 1, 50 parts of dry starch and 15 parts of polymethylene polyphenyl isocyanate to obtain starch adhesive.

[0072] The starch adhesive prepared in this example was used to prepare plywood, and the specific method was as follows:

[0073] Apply starch adhesive evenly on the wood veneer, with a single-sided adhesive amount of 240g / m 2 , pre-press at 3MPa for 30min, take out the plywood, place it in a hot press, and press it at 3MPa for 10min at a temperature of 120℃ to obtain the plywood.

[0074] Comparative Example 1

[0075] This comparative example provides a starch adhesive and uses it in the preparation of plywood.

[0076] The preparation method of the starch adhesive provided in this comparative example comprises the following steps:

[0077] Step 1: Prepare the prefabricated material: fully mix 100 parts of oxidized starch, 80 parts of gelatin and 800 parts of distilled water, stir in a 70°C water bath for 30 minutes, and then continue stirring at 75°C for 2 hours to obtain the prefabricated material;

[0078] Step 2: Prepare starch adhesive: When using, mix and stir 100 parts of the prefabricated material prepared in step 1, 50 parts of dry starch and 10 parts of polymethylene polyphenyl isocyanate to obtain starch adhesive.

[0079] The starch adhesive prepared in this comparative example was used to prepare plywood, and the specific method was as follows:

[0080] Apply starch adhesive evenly on the wood veneer, with a single-sided adhesive amount of 240g / m 2 , pre-press at 3MPa for 30min, take out the plywood, place it in a hot press, and press it at 3MPa for 10min at a temperature of 120℃ to obtain the plywood.

[0081] The bonding performance of the starch adhesives prepared using Examples 1 to 7 and Comparative Example 1 was tested. In accordance with the national standard GB / T17657-2013 "Test methods for physical and chemical properties of wood-based panels and veneered wood-based panels", the shear strength of the plywood in the dry and wet states was tested. The dry shear strength and wet shear strength data of the plywood are shown in Table 1.

[0082] Table 1

[0083] type Dry strength (MPa) Wet strength (MPa) Comparative Example 1 1.56±0.16 0.19±0.02 Example 1 7.93±0.03 1.40±0.13 Example 2 2.38±0.29 0.80±0.05 Example 3 2.65±0.35 0.46±0.09 Example 4 7.73±0.39 0.33±0.04 Example 5 2.63±0.58 1.64±0.15 Example 6 6.30±0.39 1.99±0.33 Example 7 7.91±0.03 2.00±0.24

[0084] From the comparison of the data in Table 1, it can be seen that the starch adhesive prepared by the present invention has the advantages of high bonding strength, good water resistance, no formaldehyde generation, environmental friendliness, low cost, etc., meets the national requirements for Class II boards, and has broad market prospects in the field of artificial board manufacturing.

[0085] Figure 1-Figure 3 The following are photos of the fracture surfaces of the boards after wet strength tensile testing of the adhesives prepared in Example 1, Example 5 and Comparative Example 1, respectively. It can be seen from the fracture surfaces of the boards that the high-strength starch adhesive prepared by the present invention has good bonding strength and wood breakage rate, and the wet strength is increased from 0.19 MPa to 1.40 MPa and 1.64 MPa, and the bonding stability in a humid environment is significantly improved.

Claims

1. A high-strength starch adhesive for artificial boards, characterized in that: The invention comprises the following components in parts by mass: 100 parts of prefabricated material, 50-70 parts of dry starch and 10-15 parts of isocyanate; the prefabricated material comprises the following components in parts by mass: 100 parts of oxidized starch, 80 parts of gelatin, 15-20 parts of a cross-linking agent and 800 parts of distilled water, wherein the cross-linking agent is polyethylene glycol diglycidyl ether and the isocyanate is polymethylene polyphenyl isocyanate; The preparation method of the high-strength starch adhesive for artificial boards comprises the following steps: Step 1: Prepare the prefabricated material: fully mix the oxidized starch, gelatin and distilled water, then add the cross-linking agent and continue the reaction for a certain period of time to obtain the prefabricated material; Step 2: preparing starch adhesive: when using, the prefabricated material prepared in step 1, dry starch and isocyanate are mixed and stirred evenly according to parts by mass to obtain starch adhesive.

2. The high-strength starch adhesive for artificial boards according to claim 1, characterized in that: The thorough mixing and stirring in step 1 is performed at 60-80° C. for 30 minutes.

3. The high-strength starch adhesive for artificial boards according to claim 2, characterized in that: The continued reaction in step 1 is carried out at 60-80° C. for 2-4 hours.

4. A method for using the high-strength starch adhesive for artificial boards according to claim 1, characterized in that: When using, apply the starch adhesive evenly on the wood veneer, and the amount of glue applied on one side of the board is 200-300g / m 2 The bonding is completed by pre-pressing and hot pressing. The pre-pressing is pre-pressing for 30 minutes under a pressure of 2 to 5 MPa, and the hot pressing is hot pressing for 10 minutes at a temperature of 110 to 130°C using a hot press with a pressure of 2 to 3 MPa.

5. The method for using the high-strength starch adhesive for artificial boards according to claim 4, characterized in that: It also includes placing the hot-pressed artificial board in the environment for 24 hours to eliminate internal stress.

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