A method for rapid bonding of dissimilar materials driven by ethanol

Abstract

The present invention relates to a method for rapidly bonding dissimilar materials driven by ethanol, belonging to the technical field of dissimilar material bonding methods. To solve the problem of slow bonding speed when existing adhesives are used for bonding dissimilar materials, the present invention provides a method for rapidly bonding dissimilar materials driven by ethanol. A polylactic acid composite adhesive layer sheet is prepared from polylactic acid polyol as a raw material; the obtained polylactic acid composite adhesive layer sheet is infiltrated in an ethanol solution to drive the bonding; the infiltrated polylactic acid composite adhesive layer sheet is laid between the dissimilar materials to be bonded, and a certain vertical pressure is applied to the bonding surface until the ethanol volatilizes completely, thus completing the bonding. The present invention drives the rapid bonding performance of the polylactic acid composite adhesive layer with ethanol, which not only facilitates the uniform and rapid application of the adhesive, but also can achieve a bonding strength exceeding 2 MPa under the action of a very small pressure. This method can be applied to the bonding of dissimilar materials such as wood, bamboo, steel, glass, and ceramics, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of dissimilar material bonding methods, and particularly relates to an ethanol-driven rapid bonding method for dissimilar materials. Background Art

[0002] Dissimilar material bonding refers to the process of connecting two or more different materials into an integral whole through adhesives or other connection techniques, and these materials have differences in chemical composition, metallographic structure, physical properties, or mechanical properties. Dissimilar material bonding technology is widely used in many fields such as aerospace, automotive manufacturing, electronics and electrical appliances, medical devices, and construction engineering, and is of great significance for improving the comprehensive performance of products, reducing weight, and lowering costs.

[0003] Common existing methods for dissimilar material bonding include adhesive bonding, welding, mechanical connection, etc. Among them, adhesive bonding is the most common dissimilar bonding method, and by selecting a suitable adhesive, a firm connection between materials can be achieved without damaging the properties of the base materials.

[0004] However, existing adhesives for dissimilar material bonding often have high viscosity, poor fluidity, and are not easily penetrated into the gaps between dissimilar materials, resulting in a slow bonding speed. In addition, the application method and uniformity of the adhesive will also affect the distribution and penetration effect of the adhesive, thus affecting the bonding speed. Summary of the Invention

[0005] In order to solve the problem of slow bonding speed when existing adhesives are used for dissimilar material bonding, the present invention provides an ethanol-driven rapid bonding method for dissimilar materials.

[0006] The technical solution of the present invention:

[0007] An ethanol-driven rapid bonding method for dissimilar materials, comprising the following steps:

[0008] Step 1: Prepare a polylactic acid composite adhesive layer sheet using polylactic acid polyol as a raw material;

[0009] Step 2: Immerse the polylactic acid composite adhesive layer sheet obtained in Step 1 in an ethanol solution to drive bonding;

[0010] Step 3: Lay the polylactic acid composite adhesive layer sheet that has been immersed in Step 2 between the dissimilar materials to be bonded, apply a certain vertical pressure to the bonding surface until the ethanol has completely volatilized, and the bonding is completed.

[0011] Further, the raw materials for preparing the polylactic acid composite adhesive layer sheet in Step 1 include polylactic acid polyol, isocyanate, anhydrous organic solvent, catalyst, and chain extender; the mass-to-volume ratio of polylactic acid polyol, isocyanate, anhydrous organic solvent, and chain extender is 8 - 10 g: 1 - 3 g: 80 - 120 ml: 0.1 - 1.5 g, and the dosage of the catalyst is 0.3% of the total mass of polylactic acid polyol and isocyanate.

[0012] Further, the polylactic acid polyol is one or a combination of several polylactic acid polyols with a molecular weight of 500 - 2000.

[0013] Further, the isocyanate is one or a combination of several of polymethylene polyphenyl isocyanate, toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, or lysine diisocyanate; the anhydrous organic solvent is one of methyl ethyl ketone, dioxane, N,N-dimethylformamide, or dimethylacetamide.

[0014] Further, the catalyst is a tin-based catalyst, specifically stannous octoate or stannous chloride; the chain extender is one or a combination of several of sebacoyl hydrazide, succinyl dihydrazide, or 2,5-bis(benzyloxy)terephthalohydrazide.

[0015] Further, the method for preparing the polylactic acid composite adhesive layer sheet is as follows: Place the polylactic acid polyol, isocyanate, and catalyst under an inert atmosphere and react at 70 - 90 °C for 3 - 5 h to obtain a prepolymer; add the anhydrous organic solvent and chain extender to the obtained prepolymer, lower the reaction temperature to room temperature, and continue the reaction for 24 - 48 h under an inert atmosphere to obtain a composite system; pour the obtained composite system into a mold, let it stand at room temperature, and then volatilize and remove the anhydrous organic solvent in the composite system to obtain the polylactic acid composite adhesive layer sheet.

[0016] Further, the thickness of the obtained polylactic acid composite adhesive layer sheet is 0.02 - 2 mm.

[0017] Further, the volume concentration of the ethanol solution in Step 2 is 50 - 100%, and the infiltration time is 10 - 60 s.

[0018] Further, the dissimilar materials in Step 3 include wood, bamboo, iron, aluminum, copper, stainless steel, glass, ceramics, plastics, and rubber.

[0019] Further, the pressure is not less than 5000 Pa.

[0020] The beneficial effects of the present invention:

[0021] The bonding method provided by the present invention uses the polylactic acid composite adhesive layer of the sheet as the adhesive, and ethanol is used to drive the rapid bonding performance of the polylactic acid composite adhesive layer. It is laid flat between the dissimilar materials to be bonded. It is not only easy to achieve uniform and rapid sizing, but also can achieve a bonding strength of more than 2 MPa under a very small pressure. The rapid bonding method of dissimilar materials driven by ethanol of the present invention can be applied to the bonding of dissimilar materials such as wood, bamboo, steel, glass, and ceramics, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a comparison chart of the bonding strengths of different dissimilar materials bonded by the rapid bonding method in Examples 1-5;

[0023] Figure 2 It is a physical demonstration diagram of the bonding strength of bamboo slices and iron sheets bonded by the rapid bonding method provided in Example 1. The weight of the dumbbell in the figure is 10 kg. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The technical solutions of the present invention will be further described below in conjunction with the embodiments, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall be covered by the protection scope of the present invention. For the process equipment or devices not specifically noted in the following embodiments, conventional equipment or devices in the art are used. If not specifically specified, the raw materials used in the embodiments of the present invention can be obtained commercially; if not specifically specified, the technical means used in the embodiments of the present invention are conventional means well known to those skilled in the art.

[0025] Example 1

[0026] This example provides a rapid bonding method for dissimilar materials driven by ethanol, including the following steps:

[0027] Step 1: Prepare a polylactic acid composite adhesive layer sheet using polylactic acid polyol as the raw material;

[0028] First, weigh 8.82 g of polylactic acid polyol PLA-OH in a four-necked flask connected to a vacuum pump, stir to remove moisture, add 1.03 g of IPDI, add stannous octoate at 0.3% of the total mass of polylactic acid polyol and isocyanate, introduce nitrogen, and react at 80 °C for 3.5 h to obtain a prepolymer; add 100 ml of methyl ethyl ketone to the obtained prepolymer to reduce the viscosity of the reaction system. After the system is cooled to room temperature of 25 °C, add 0.11 g of IPDH for chain extension reaction, and react under nitrogen for 12 h to obtain a composite system; pour the obtained composite system into a mold, let it stand at room temperature overnight, and then send it to an oven at 50 °C for 24 h to volatilize the methyl ethyl ketone in the composite system, and a polylactic acid composite adhesive layer sheet with a thickness of 0.2 mm is obtained.

[0029] Step 2: Immerse the polylactic acid composite adhesive layer sheet obtained in Step 1 in an ethanol solution with a volume concentration of 100% for 30 s to drive bonding;

[0030] Step 3: Lay the polylactic acid composite adhesive layer sheet that has been immersed in Step 2 between two dissimilar materials, namely bamboo and iron sheets, which need to be bonded, and apply a vertical pressure of 5000 Pa to the bonding surface until the ethanol has completely evaporated, thus completing the bonding.

[0031] Example 2

[0032] This example provides a rapid bonding method for dissimilar materials driven by ethanol, which includes the following steps:

[0033] Step 1: Prepare a polylactic acid composite adhesive layer sheet using polylactic acid polyol as the raw material;

[0034] First, weigh 8.82 g of polylactic acid polyol PLA-OH in a four-necked flask connected to a vacuum pump, stir to remove moisture, add 1.03 g of IPDI, add stannous octoate at 0.3% of the total mass of polylactic acid polyol and isocyanate, introduce nitrogen gas, and react at 80 °C for 3.5 h to obtain a prepolymer; add 100 ml of methyl ethyl ketone to the obtained prepolymer to reduce the viscosity of the reaction system, lower the system temperature to room temperature of 25 °C, and then add 0.11 g of IPDH for chain extension reaction. React under nitrogen gas throughout for 12 h to obtain a composite system; pour the obtained composite system into a mold, let it stand at room temperature overnight, and then send it to an oven at 50 °C for 24 h to volatilize and remove the methyl ethyl ketone in the composite system, thus obtaining a polylactic acid composite adhesive layer sheet with a thickness of 0.2 mm.

[0035] Step 2: Immerse the polylactic acid composite adhesive layer sheet obtained in Step 1 in an ethanol solution with a volume concentration of 100% for 30 s to drive bonding;

[0036] Step 3: Lay the polylactic acid composite adhesive layer sheet that has been immersed in Step 2 between two dissimilar materials, namely bamboo and ceramic, which need to be bonded, and apply a vertical pressure of 5000 Pa to the bonding surface until the ethanol has completely evaporated, thus completing the bonding.

[0037] Example 3

[0038] This example provides a rapid bonding method for dissimilar materials driven by ethanol, which includes the following steps:

[0039] Step 1: Prepare a polylactic acid composite adhesive layer sheet using polylactic acid polyol as the raw material;

[0040] First, weigh 8.82 g of polylactic acid polyol PLA-OH in a four-necked flask connected to a vacuum pump, stir to remove moisture, add 1.03 g of IPDI, and add stannous octoate accounting for 0.3% of the total mass of the polylactic acid polyol and isocyanate. Introduce nitrogen gas and react at 80 °C for 3.5 h to obtain a prepolymer; add 100 ml of methyl ethyl ketone to the obtained prepolymer to reduce the viscosity of the reaction system. After cooling the system to room temperature (25 °C), add 0.11 g of IPDH for chain extension reaction. React under a nitrogen atmosphere for 12 h to obtain a composite system; pour the obtained composite system into a mold, let it stand at room temperature overnight, and then send it to an oven at 50 °C for 24 h to volatilize and remove the methyl ethyl ketone in the composite system, thus obtaining a polylactic acid composite adhesive layer sheet with a thickness of 0.2 mm.

[0041] Step 2: Immerse the polylactic acid composite adhesive layer sheet obtained in Step 1 in an ethanol solution with a volume concentration of 100% for 30 s to drive adhesion.

[0042] Step 3: Lay the polylactic acid composite adhesive layer sheet that has been immersed in Step 2 between two dissimilar materials, namely bamboo slices and glass, which need to be bonded. Apply a vertical pressure of 5000 Pa to the bonding surface until the ethanol has completely evaporated, thus completing the bonding.

[0043] Example 4

[0044] This example provides a rapid bonding method for dissimilar materials driven by ethanol, which includes the following steps:

[0045] Step 1: Prepare a polylactic acid composite adhesive layer sheet using polylactic acid polyol as the raw material.

[0046] First, weigh 8.82 g of polylactic acid polyol PLA-OH in a four-necked flask connected to a vacuum pump, stir to remove moisture, add 1.03 g of IPDI, and add stannous octoate accounting for 0.3% of the total mass of the polylactic acid polyol and isocyanate. Introduce nitrogen gas and react at 80 °C for 3.5 h to obtain a prepolymer; add 100 ml of methyl ethyl ketone to the obtained prepolymer to reduce the viscosity of the reaction system. After cooling the system to room temperature (25 °C), add 0.11 g of IPDH for chain extension reaction. React under a nitrogen atmosphere for 12 h to obtain a composite system; pour the obtained composite system into a mold, let it stand at room temperature overnight, and then send it to an oven at 50 °C for 24 h to volatilize and remove the methyl ethyl ketone in the composite system, thus obtaining a polylactic acid composite adhesive layer sheet with a thickness of 0.2 mm.

[0047] Step 2: Immerse the polylactic acid composite adhesive layer sheet obtained in Step 1 in an ethanol solution with a volume concentration of 100% for 30 s to drive adhesion.

[0048] Step 3: Lay the polylactic acid composite adhesive layer sheet that has been infiltrated in Step 2 between two dissimilar materials, namely bamboo and stainless steel, which need to be bonded. Apply a vertical pressure of 5000 Pa to the bonding surface until the ethanol has completely evaporated, thus completing the bonding.

[0049] Example 5

[0050] This example provides a rapid bonding method for dissimilar materials driven by ethanol, which includes the following steps:

[0051] Step 1: Prepare a polylactic acid composite adhesive layer sheet using polylactic acid polyol as the raw material;

[0052] First, weigh 8.82 g of polylactic acid polyol PLA-OH in a four-necked flask connected to a vacuum pump, stir to remove moisture, add 1.03 g of IPDI, and add stannous octoate at 0.3% of the total mass of polylactic acid polyol and isocyanate. Introduce nitrogen gas and react at 80 °C for 3.5 h to obtain a prepolymer; add 100 ml of methyl ethyl ketone to the obtained prepolymer to reduce the viscosity of the reaction system. After cooling the system to room temperature (25 °C), add 0.11 g of IPDH for chain extension reaction, and react under nitrogen gas for 12 h to obtain a composite system; pour the obtained composite system into a mold, let it stand at room temperature overnight, and then send it to an oven at 50 °C for 24 h to volatilize and remove the methyl ethyl ketone in the composite system, thus obtaining a polylactic acid composite adhesive layer sheet with a thickness of 0.2 mm.

[0053] Step 2: Immerse the polylactic acid composite adhesive layer sheet obtained in Step 1 in an ethanol solution with a volume concentration of 100% for 30 s to drive the bonding;

[0054] Step 3: Lay the polylactic acid composite adhesive layer sheet that has been infiltrated in Step 2 between two dissimilar materials, namely bamboo and wood, which need to be bonded. Apply a vertical pressure of 5000 Pa to the bonding surface until the ethanol has completely evaporated, thus completing the bonding.

[0055] Figure 1 The figure shows the comparison of the bonding strengths of the rapid bonding methods in Examples 1 - 5 for bonding different dissimilar materials. The picture shows that the bonding strength of Example 1 for bonding two dissimilar materials, bamboo and iron sheet, is 6.4 ± 1.2 MPa; the bonding strength of Example 2 for bonding two dissimilar materials, bamboo and ceramic, is 6.3 ± 1.6 MPa; the bonding strength of Example 3 for bonding two dissimilar materials, bamboo and glass, is 2.6 ± 0.7 MPa; the bonding strength of Example 4 for bonding two dissimilar materials, bamboo and stainless steel, is 5.3 ± 1.2 MPa; the bonding strength of Example 5 for bonding two dissimilar materials, bamboo and wood, is 11.8 ± 1.1 MPa. Thus, it can be proved that the ethanol-driven rapid bonding method for dissimilar materials provided by the present invention has a good bonding effect on dissimilar materials, and the highest bonding strength can reach 11.8 MPa.

Claims

1. A method for rapid bonding of dissimilar materials driven by ethanol, characterized in that, It includes the following steps: Step 1: Prepare a polylactic acid composite adhesive layer sheet using polylactic acid polyol as the raw material. The raw materials for preparing the polylactic acid composite adhesive layer sheet include polylactic acid polyol, isocyanate, anhydrous organic solvent, catalyst, and chain extender; wherein the mass-volume ratio of polylactic acid polyol, isocyanate, anhydrous organic solvent, and chain extender is 8-10 g: 1-3 g: 80-120 ml: 0.1-1.5 g, and the dosage of the catalyst is 0.3% of the total mass of polylactic acid polyol and isocyanate; the isocyanate is one or a combination of polymethylene polyphenyl isocyanate, toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, or lysine diisocyanate; Step 2: Immerse the polylactic acid composite adhesive layer sheet obtained in Step 1 in an ethanol solution to drive adhesion; Step 3: Lay the polylactic acid composite adhesive layer sheet that has been immersed in Step 2 between dissimilar materials to be bonded, apply a certain vertical pressure to the bonding surface until the ethanol has completely evaporated, and the bonding is completed.

2. The rapid adhesive bonding method of dissimilar materials driven by ethanol according to claim 1, wherein The polylactic acid polyol is one or a combination of polylactic acid polyols with a molecular weight of 500-2000.

3. The rapid adhesive bonding method for dissimilar materials driven by ethanol according to claim 2, wherein The anhydrous organic solvent is one of methyl ethyl ketone, dioxane, N,N-dimethylformamide, or dimethylacetamide.

4. The rapid adhesive bonding method for dissimilar materials driven by ethanol according to claim 3, wherein The catalyst is a tin-based catalyst, specifically stannous octoate or stannous chloride; the chain extender is one or a combination of sebacoyl hydrazide, succinic dihydrazide, or 2,5-bis(benzyloxy)terephthalohydrazide.

5. A rapid bonding method for dissimilar materials driven by ethanol according to any one of claims 1-4, characterized in that, The preparation method of the polylactic acid composite adhesive layer sheet is as follows: Place the polylactic acid polyol, isocyanate, and catalyst under an inert atmosphere and react at a temperature of 70-90 °C for 3-5 h to obtain a prepolymer; add the anhydrous organic solvent and chain extender to the obtained prepolymer, lower the reaction temperature to room temperature, and continue to react under an inert atmosphere for 24-48 h to obtain a composite system; pour the obtained composite system into a mold, let it stand at room temperature, and then volatilize and remove the anhydrous organic solvent in the composite system to obtain the polylactic acid composite adhesive layer sheet.

6. The rapid adhesive bonding method of dissimilar materials driven by ethanol according to claim 5, wherein The thickness of the obtained polylactic acid composite adhesive layer sheet is 0.02-2 mm.

7. The rapid adhesive bonding method of dissimilar materials driven by ethanol according to claim 6, characterized in that, The volume concentration of the ethanol solution in Step 2 is 50-100%, and the immersion time is 10-60 s.

8. The rapid bonding method of dissimilar materials driven by ethanol according to claim 7, characterized in that, The dissimilar materials in Step 3 include wood, bamboo, iron, aluminum, copper, stainless steel, glass, ceramics, plastics, and rubber.

9. The rapid bonding method of dissimilar materials driven by ethanol according to claim 8, characterized in that, The pressure is not less than 5000 Pa.

Images