Modified castor oil-based polyurethane adhesive, and preparation method and application thereof

Abstract

The application relates to the technical field of organic polymer adhesives, and particularly discloses a modified castor oil-based polyurethane adhesive as well as a preparation method and application thereof. The adhesive is a two-component adhesive, wherein, according to weight fractions, the A component is modified castor oil 30.0-50.0 parts and refined castor oil 0.0-30.0 parts; the B component includes polyisocyanate or polyisocyanate modifier 30.0-50.0 parts and water removal agent 0.00-0.05 parts; and the modified castor oil is prepared from refined castor oil and cysteamine through a mercapto-alkene addition reaction. The amine group of the modified castor oil is weakly alkaline, and the reaction speed with the isocyanate group is fast; hydrogen bonds are easily generated between the urea bonds generated by the reaction of the amine group and the isocyanate group, so that the adhesive is endowed with thixotropy and high strength. The adhesive has simple composition, fast reaction speed, good thixotropy and bonding strength.

Description

Technical Field

[0001] This invention belongs to the field of organic polymer adhesive technology, specifically relating to a modified castor oil-based polyurethane adhesive, its preparation method, and its application. Background Technology

[0002] Castor oil is a vegetable oil extracted from castor seeds. Its molecular structure contains both reactive hydroxyl groups and carbon-carbon double bonds in each molecular chain. Compared to other vegetable oils such as tung oil, soybean oil, and linseed oil, castor oil has greater polarity, allowing it to be compatible and react with various isocyanate compounds to prepare polyurethane materials for different applications.

[0003] Various adhesives are used in the assembly process of new energy battery packs. Polyurethane adhesives possess excellent shear strength, impact resistance, and high and low temperature resistance, and can firmly bond to a variety of substrates such as metals, fabrics, leather, wood, and plastics. They are widely used in the potting, bonding, and encapsulation processes of automotive battery packs. The adhesive strength, thixotropy, and curing speed of adhesives are important indicators for evaluating their application and workability, placing higher demands on adhesive formulation design and material selection. In particular, with increasing environmental awareness and a gradual decrease in dependence on petrochemical resources, new challenges arise in the preparation of high-performance adhesives using renewable resources (which face challenges such as limited variety, complex composition, and difficulty in modification).

[0004] To address the problems existing in the prior art, there is a need to provide a castor oil-based polyurethane adhesive that simultaneously possesses thixotropic properties, fast reaction speed, and high adhesive performance. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a thixotropic and rapidly reactive castor oil-based polyurethane adhesive, its preparation method, and its application. The modified castor oil molecular chain allows for the formation of numerous multiple hydrogen bonds between the primary amino group (-NH2) and the acylaminourea bond of the isocyanate group (-NCO), endowing the adhesive with excellent thixotropic properties and high strength. Furthermore, the amine group is weakly basic and can catalyze the reaction between -NH2 and hydroxyl groups (-OH) and -NCO, efficiently completing the curing process.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention is to provide a castor oil-based polyurethane adhesive with thixotropic properties and rapid reaction capability. The adhesive is a two-component adhesive, wherein, by weight, component A comprises 30.0-50.0 parts of modified castor oil and 0.0-30.0 parts of refined castor oil; component B comprises 30.0-50.0 parts of polyisocyanate or polyisocyanate modifier and 0.00-0.05 parts of dehydrating agent.

[0008] The method for preparing the modified castor oil includes the following steps:

[0009] S1. Add the mixture of refined castor oil and cysteine ​​at a molar ratio of 1:2~3, and add 3-8% of initiator and solvent (calcium cysteine ​​molar amount), stir, and obtain a solution with a mass concentration of 25-50%.

[0010] S2. Under a high-purity nitrogen atmosphere, with stirring and at 60-85℃, the reaction is carried out for 10-24 h to obtain the product solution;

[0011] S3. After removing the solvent from the product solution using a rotary evaporator, place it in a vacuum drying oven at 40°C and dry it to constant weight to obtain the modified castor oil product.

[0012] Furthermore, the molecular structural formula of the modified castor oil is as follows: Where ab is a C-C single bond, then R = If ab is a C=C double bond, R = H, and the number of double bonds in ab is ≤1.

[0013] Furthermore, the structural formula of the diisocyanate is as follows: (IPDI) (HMDI) (MDI) (HDI) (TDI) (TDI) (TMXDI) (XDI) (TMDI) or At least one of (TMDI).

[0014] Furthermore, the polyisocyanate and the polyisocyanate modifier are at least one of TDI trimer, HDI trimer, IPDI trimer, polyphenyl polymethylene polyisocyanate (PAPI), PM-200 (Yantai Wanhua), NT-8075 (Wuhan Shiquanxing), S-325 (Wuhan Shiquanxing) or S-310 (Wuhan Shiquanxing).

[0015] Furthermore, the initiator is at least one selected from azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, and azobiscyclohexylformitrile; the solvent is at least one selected from 1,4-dioxane, tetrahydrofuran, methyl ethyl ketone, butyl acetate, ethyl acetate, and toluene.

[0016] Furthermore, the dehydrating agent is at least one of p-toluenesulfonyl isocyanate, 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine, 3-butyl-2-(1-ethylpentyl)oxazolidine, and 2-methyl-2-ethyl-3-hydroxyethyl-1,3-oxazolidine.

[0017] A second aspect of the present invention is to provide a method for preparing the above-mentioned polyurethane adhesive, wherein the preparation method comprises preparing the following components in parts by weight:

[0018] Component A: 30.0~50.0 parts of modified castor oil, 0.0~30.0 parts of refined castor oil; Component B: 30.0~50.0 parts of polyisocyanate or polyisocyanate modifier, 0.00~0.05 parts of dehydrating agent;

[0019] At room temperature, component A is mixed, degassed under vacuum, and then filled into packaging and sealed. Component B is mixed, degassed under vacuum at room temperature, filled into packaging, and sealed to obtain polyurethane adhesive.

[0020] A third aspect of the present invention is to provide the application of the modified castor oil-based polyurethane adhesive described above in the packaging and assembly process of new energy batteries.

[0021] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are:

[0022] (1) Fast reaction rate. The double bond in the castor oil molecule reacts with cysteine ​​through a mercapto-olefin addition reaction, introducing a primary amine functional group into the castor oil molecule structure. The primary amine group (-NH2) is weakly basic and can react rapidly with the isocyanate group, increasing the viscosity of the system and completing the curing process in a short time.

[0023] (2) Imparting thixotropic properties to adhesives. The primary amine groups of modified castor oil react with -NCO to generate urea groups. A large number of intermolecular hydrogen bonds can spontaneously form between urea groups, imparting thixotropic properties and high strength to the adhesives.

[0024] (3) Environmentally friendly and sustainable use of raw materials. Castor oil is derived from plant seeds and is a sustainable resource. Castor oil accounts for a large proportion of the adhesive formulation, which helps reduce the consumption of petrochemical resources and is conducive to environmental protection and sustainable resource development. Attached Figure Description

[0025] Figure 1 Infrared spectra of the modified castor oil and refined castor oil prepared in Example 1;

[0026] Figure 2 Infrared spectra of the modified castor oil and refined castor oil prepared in Example 2;

[0027] Figure 3DSC curves for samples from Example 1 and Comparative Example 1;

[0028] Figure 4 Shear tensile curves of the samples from Example 1 and Comparative Example 1;

[0029] Figure 5 The relationship between thixotropy and reaction time is shown for the samples of Example 1 and Comparative Example 1. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the specific embodiments and accompanying drawings are described in further detail below. Where specific test methods, instruments, or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0031] This invention provides a method for preparing a castor oil-based polyurethane adhesive with thixotropic properties and rapid reaction. The preparation method comprises, by weight, the following components: 30.0-50.0 parts of modified castor oil, 0.0-30.0 parts of refined castor oil, 30.0-50.0 parts of polyisocyanate or polyisocyanate modifier, and 0.00-0.05 parts of dehydrating agent;

[0032] Modified castor oil is degassed under vacuum at room temperature, then filled into packaging materials and sealed; polyisocyanate or polyisocyanate modifier is mixed with dehydrating agent at room temperature, degassed under vacuum, filled into packaging materials, and sealed to obtain polyurethane adhesive.

[0033] The preparation method of modified castor oil includes the following steps:

[0034] S1. Add the mixture of refined castor oil and cysteine ​​at a molar ratio of 1:2~3, and add 3-8% of initiator and solvent (calcium cysteine ​​molar amount), stir, and obtain a solution with a mass concentration of 25-50%.

[0035] S2. Under a high-purity nitrogen atmosphere, with stirring and at 60-85℃, the reaction is carried out for 10-24 h to obtain the product solution;

[0036] S3. After removing the solvent from the product solution using a rotary evaporator, place it in a vacuum drying oven at 40°C and dry it to constant weight to obtain the modified castor oil product.

[0037] The molecular structural formula of modified castor oil is as follows: Where ab is a C-C single bond, then R = If ab is a C=C double bond, R = H, and the number of double bonds in ab is ≤1; the structural formula of the polyisocyanate is: (IPDI) (HMDI) (MDI) (HDI) (TDI) (TDI) (TMXDI) (XDI) (TMDI) or At least one of (TMDI); the polyisocyanate and its modified polyisocyanate are at least one of TDI trimer, HDI trimer, IPDI trimer, polyphenyl polymethylene polyisocyanate (PAPI), PM-200 (Yantai Wanhua), NT-8075 (Wuhan Shiquanxing), S-325 (Wuhan Shiquanxing) or S-310 (Wuhan Shiquanxing); the initiator is azobisisobutyronitrile, azobisisoheptanenitrile, or azobisisobutyric acid. The solvent is at least one of dimethyl ester and azobiscyclohexyl formonitrile; the solvent is at least one of 1,4-dioxane, tetrahydrofuran, methyl ethyl ketone, butyl acetate, ethyl acetate, and toluene; the dehydrating agent is at least one of p-toluenesulfonyl isocyanate, 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine, 3-butyl-2-(1-ethylpentyl)oxazolidine, and 2-methyl-2-ethyl-3-hydroxyethyl-1,3-oxazolidine.

[0038] The modified castor oil-based polyurethane adhesive provided by this invention can be prepared by following the above methods. Specific examples are described below.

[0039] Example 1

[0040] This embodiment provides a method for preparing a modified castor oil-based polyurethane adhesive with thixotropic properties and rapid reaction, as detailed below:

[0041] S1. 20.00 g (0.021 mol) of refined castor oil (hydroxyl value of 36.86 mgKOH / 100g, iodine value of 80 g / 100g), 3.24 g (0.042 mol) of cysteine, and 0.7738 g (3.36 mmol) of dimethyl azobisisobutyrate were added sequentially to a single-necked round-bottom flask, and 24.1 g of tetrahydrofuran was added. The mixture was stirred to obtain a reaction solution with a mass concentration of 50%.

[0042] S2. Under a high-purity nitrogen atmosphere, with stirring and at 60 °C, the reaction was carried out for 24 h to obtain the product solution;

[0043] S3. After removing the solvent from the product solution using a rotary evaporator, place it in a vacuum drying oven at 40°C and dry it to constant weight to obtain the modified castor oil product.

[0044] 50.00 g of modified castor oil and 10.0 g of refined castor oil were mixed, degassed under vacuum, and then filled into packaging materials and sealed to obtain polyurethane adhesive component A. At room temperature, 50.00 g of PM-200 and 0.05 g of 2-methyl-2-ethyl-3-hydroxyethyl-1,3-oxazolidine were mixed, degassed under vacuum, filled into packaging materials, and sealed to obtain polyurethane adhesive component B.

[0045] Comparative Example 1

[0046] 60.00 g of refined castor oil was degassed under vacuum, then filled into packaging materials and sealed to obtain polyurethane adhesive component A; at room temperature, 23.8 g of PM-200 (based on a molar ratio of NCO to OH or NH2 of 1:1) was mixed with 0.05 g of 2-methyl-2-ethyl-3-hydroxyethyl-1,3-oxazolidine, degassed under vacuum, filled into packaging materials, and sealed to obtain polyurethane adhesive component B.

[0047] Example 2

[0048] This embodiment provides a method for preparing a modified castor oil-based polyurethane adhesive with thixotropic properties and rapid reaction, as detailed below:

[0049] S1. 20.00 g (0.021 mol) of refined castor oil (hydroxyl value of 36.86 mgKOH / 100g, iodine value of 80 g / 100g), 4.86 g (0.063 mol) of cysteine, and 0.3104 g (1.89 mmol) of azobisisobutyronitrile were added sequentially to a single-necked round-bottom flask, and 75.51 g of 1,4-dioxane was added. The mixture was stirred to obtain a reaction solution with a mass concentration of 25%.

[0050] S2. Under a high-purity nitrogen atmosphere, with stirring and at 85 °C, the reaction was carried out for 10 h to obtain the product solution.

[0051] S3. After removing the solvent from the product solution using a rotary evaporator, place it in a vacuum drying oven at 40°C and dry it to constant weight to obtain the modified castor oil product.

[0052] 30.00 g of modified castor oil was degassed under vacuum, then filled into packaging materials and sealed to obtain polyurethane adhesive component A; at room temperature, 8.30 g of TDI (mol) and 21.70 g of IPDI (mol) TDI : mol IPDIMix (ratio 1:2), degas under vacuum, fill into packaging materials, and seal to obtain component B of the polyurethane adhesive.

[0053] Comparative Example 2

[0054] 30.00 g of refined castor oil was degassed under vacuum, then filled into packaging materials and sealed to obtain component A of the polyurethane adhesive; at room temperature, 2.76 g of TDI (based on a molar ratio of NCO and OH or NH2 of 1:1) and 7.03 g of IPDI (mol) TDI :mol IPDI Mix (ratio 1:2), degas under vacuum, fill into packaging materials, and seal to obtain component B of the polyurethane adhesive.

[0055] Example 3

[0056] This embodiment provides a method for preparing a modified castor oil-based polyurethane adhesive with thixotropic properties and rapid reaction, as detailed below:

[0057] S1. 20.00 g (0.021 mol) of refined castor oil (hydroxyl value 36.86 mgKOH / 100g, iodine value 80 g / 100g), 4.05 g (0.0525 mol) of cysteine, 0.2810 g (1.15 mmol) of azobiscyclohexylformonitrile, and 0.4967 g (2.00 mmol) of azobisisoheptanenitrile were added sequentially to a single-necked round-bottom flask, and 57.5 g of toluene was added. The mixture was stirred to obtain a reaction solution with a mass concentration of 30%.

[0058] S2. Under a high-purity nitrogen atmosphere, with stirring and at 80 °C, the product solution was obtained after 20 h of reaction.

[0059] S3. After removing the solvent from the product solution using a rotary evaporator, place it in a vacuum drying oven at 40°C and dry it to constant weight to obtain the modified castor oil product.

[0060] 30.00 g of modified castor oil and 30.00 g of refined castor oil were mixed, degassed under vacuum, and then filled into packaging materials and sealed to obtain polyurethane adhesive component A. At room temperature, 50.00 g of TDI trimer and 0.001 g of toluenesulfonyl isocyanate were mixed, degassed under vacuum, filled into packaging materials, and sealed to obtain polyurethane adhesive component B.

[0061] Example 4

[0062] This embodiment provides a method for preparing a modified castor oil-based polyurethane adhesive with thixotropic properties and rapid reaction, as detailed below:

[0063] S1. 20.00 g (0.021 mol) of refined castor oil (hydroxyl value 36.86 mgKOH / 100g, iodine value 80 g / 100g), 3.56 g (0.0462 mol) of cysteine, 0.1174 g (0.51 mmol) of dimethyl azobisisobutyrate, and 0.2956 g (1.80 mmol) of azobisisobutyronitrile were added sequentially to a single-necked round-bottom flask, followed by 16.01 g of methyl ethyl ketone and 20.00 g of toluene. The mixture was stirred to obtain a reaction solution with a mass concentration of 40%.

[0064] S2. Under a high-purity nitrogen atmosphere, with stirring and at 70 °C, the reaction was carried out for 15 h to obtain the product solution.

[0065] S3. After removing the solvent from the product solution using a rotary evaporator, place it in a vacuum drying oven at 40°C and dry it to constant weight to obtain the modified castor oil product.

[0066] 40.00 g of modified castor oil and 20.00 g of refined castor oil were mixed, degassed under vacuum, and then filled into packaging materials and sealed to obtain polyurethane adhesive component A. At room temperature, 20.60 g of XDI, 10.65 g of S-310 (Shi Quanxing) and 0.006 g of 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine were mixed, degassed under vacuum, filled into packaging materials, and sealed to obtain polyurethane adhesive component B.

[0067] Example 5

[0068] This embodiment provides a method for preparing a modified castor oil-based polyurethane adhesive with thixotropic properties and rapid reaction, as detailed below:

[0069] S1. 20.00 g (0.021 mol) of refined castor oil (hydroxyl value of 36.86 mgKOH / 100g, iodine value of 80 g / 100g), 4.54 g (0.0588 mol) of cysteine, and 0.5517 g (3.36 mmol) of azobisisobutyronitrile were added sequentially to a single-necked round-bottom flask, followed by the addition of 36.1 g of 1,4-dioxane and 10.0 g of butyl acetate. The mixture was stirred to obtain a reaction solution with a mass concentration of 35%.

[0070] S2. Under a high-purity nitrogen atmosphere, with stirring and at 65 °C, the reaction was carried out for 24 h to obtain the product solution;

[0071] S3. After removing the solvent from the product solution using a rotary evaporator, place it in a vacuum drying oven at 40°C and dry it to constant weight to obtain the modified castor oil product.

[0072] 50.00 g of modified castor oil was degassed under vacuum, then filled into packaging materials and sealed to obtain polyurethane adhesive component A; at room temperature, 19.80 g of MDI, 20.45 g of TDI trimer and 0.04 g of 3-butyl-2-(1-ethylpentyl)oxazolidine were mixed, degassed under vacuum, filled into packaging materials and sealed to obtain polyurethane adhesive component B.

[0073] Example 6

[0074] This embodiment provides a method for preparing a modified castor oil-based polyurethane adhesive with thixotropic properties and rapid reaction, as detailed below:

[0075] S1. 20.00 g (0.021 mol) of refined castor oil (hydroxyl value 36.86 mgKOH / 100g, iodine value 80 g / 100g), 3.24 g (0.042 mol) of cysteine, 0.1174 g (0.51 mmol) of dimethyl azobisisobutyrate, and 0.2810 g (1.15 mmol) of azobiscyclohexylformonitrile were sequentially added to a single-necked round-bottom flask, followed by the addition of 37.3 g of toluene and 10.0 g of ethyl acetate. The mixture was stirred to obtain a reaction solution with a mass concentration of 33%.

[0076] S2. Under a high-purity nitrogen atmosphere, stirring and at 75 °C, the reaction was carried out for 20 h to obtain the product solution.

[0077] S3. After removing the solvent from the product solution using a rotary evaporator, place it in a vacuum drying oven at 40°C and dry it to constant weight to obtain the modified castor oil product.

[0078] 40.00 g of modified castor oil and 25.00 g of refined castor oil were mixed, degassed under vacuum, and then filled into packaging materials and sealed to obtain polyurethane adhesive component A. At room temperature, 11.91 g of XDI, 10.51 g of PM-200, 13.35 g of HDI trimer and 0.001 g of toluenesulfonyl isocyanate were mixed, degassed under vacuum, filled into packaging materials, and sealed to obtain polyurethane adhesive component B.

[0079] Performance testing and comparative experiments

[0080] (1) Characterization of product structure

[0081] The modified castor oil and refined castor oil prepared in Examples 1 and 2 were subjected to infrared spectroscopy using the potassium bromide tablet method. The test results are shown in the figure. Figure 1 and Figure 2 .

[0082] As shown in the figure, the control sample refined castor oil was tested at a wavenumber of 1739 cm⁻¹. -1A strong absorption peak is observed at 1739 cm⁻¹ (attributed to the CH₂=CH₂ absorption peak in the castor oil structure). Example 1 shows a peak at 1739 cm⁻¹. -1 The decrease in absorption peak intensity at 1739 cm⁻¹ indicates that most of the CH₂=CH₂ bonds underwent a thiol-olefin addition reaction with cysteine; Example 2 showed an absorption peak intensity at 1739 cm⁻¹. -1 The absorption peak at that point has almost disappeared, indicating that the vast majority of CH2=CH2 bonds participated in the reaction. Meanwhile, Figure 1 and Figure 2 Middle, 3417-3445 cm -1 The absorption peaks at this location (attributed to -OH and -NH2) showed significant changes in shape and intensity compared to the absorption peaks of refined castor oil, proving that the modified product was successfully prepared.

[0083] (2) Reaction performance

[0084] The polyurethane adhesives obtained in Example 1 and Comparative Example 1 were mixed in a specific ratio, and their reactivity was determined by Netzsch DSC. The test results are shown in the figure. Figure 3 See Table 1. Test conditions: nitrogen atmosphere, heating rate 20 ℃ / min, test temperature range 30 ~ 200 ℃.

[0085] from Figure 3 As can be seen from Table 1, the initial reaction temperature (T) of the adhesive measured in Example 1 is... on ), exothermic peak temperature (T) peak ), termination reaction temperature (T) end The values ​​of both Example 1 and Comparative Example 1 are lower than those of Comparative Example 1, indicating that the polyurethane adhesive obtained in Example 1 reacts faster. Table 1 shows the reaction enthalpy change (ΔH) values ​​of Example 1 and Comparative Example 1. Compared to Comparative Example 1, Example 1 contains more reactive groups (-OH, -NH2) participating in the reaction in the same mass of adhesive.

[0086] Table 1. DSC measurement results of Example 1 and Comparative Example 1

[0087]

[0088] Figure 4 The figures show the viscosity versus reaction time curves of the mixtures (components A and B) of Examples 1 and Comparative Example 1, measured using a Brookfield viscometer at room temperature (18-20°C). It can be seen that the viscosity of Example 1 increases rapidly within the first 30 minutes, but the rate of increase slows down after 30 minutes. While the viscosity of Comparative Example 1 also increases, the rate of increase is slower. This indicates that the polyurethane adhesive obtained in Example 1 reacts faster than that in Comparative Example 1. Figure 3 , Figure 4The test results demonstrate that the -NH2 introduced into the castor oil molecular chain has a significant catalytic effect on the curing reaction of adhesives.

[0089] (3) Adhesive performance

[0090] Components A and B of Example 1 and Comparative Example 1 were mixed in proportion and cured in a 60 °C forced-air oven for 4 h to prepare specimens for tensile-shear testing. The specimens were subjected to tensile testing on a universal testing machine at a tensile speed of 1 mm / min, and stress-strain curves were obtained. Figure 5 ).from Figure 5 It can be seen that the tensile shear strength of the specimen prepared in Example 1 was 6.13 MPa, and the elongation at break was 1.34%; while the tensile shear strength of the specimen prepared in Comparative Example 1 was 1.76 MPa, and the elongation at break was 0.93%. This indicates that the specimen obtained in Example 1 has higher bonding performance.

[0091] The components A and B of the remaining examples and comparative examples were mixed in proportion and cured in a 60 °C forced-air oven for 4 h to prepare specimens for tensile and shear tests. The tensile strength and elongation at break measured are summarized in Table 2. As can be seen from the data in Table 2, the bonding performance of the examples is much higher than that of the comparative examples.

[0092] Table 2. Adhesive properties of each embodiment and Comparative Example 2

[0093]

[0094] (4) Thixotropic properties

[0095] Components A and B of Examples 1 and 2 and Comparative Examples 1 and 2 were mixed in proportion and left at room temperature for 30 min. The viscosity was measured using a Brookfield viscometer at two shear rates of 10 rpm and 100 rpm, respectively, and the results were η. 10 and η 100 After reacting for 30 min in Examples 1 and 2, the thixotropic indices of Examples 1 and 2 were 1.27 and 1.24, respectively, showing better thixotropic properties than those of Comparative Examples 1 and 2. This indicates that the reaction of the amine group with the isocyanate produces a urea functional group, and the hydrogen bonds between the urea functional groups exhibit some thixotropic properties.

[0096] Table 3. Adhesive properties of each embodiment and comparative example

[0097]

[0098] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0099] 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 within the protection scope of the present invention.

Claims

1. A modified castor oil-based polyurethane adhesive, characterized in that, It includes two components, A and B. By weight, component A includes 30.0-50.0 parts of modified castor oil and 0.0-30.0 parts of refined castor oil, and component B includes 30.0-50.0 parts of polyisocyanate or polyisocyanate modifier and 0.00-0.05 parts of dehydrating agent. The method for preparing the modified castor oil includes the following steps: S1. Add the mixture of refined castor oil and cysteine ​​at a molar ratio of 1:2~3, and add 3-8% of initiator and solvent (calcium cysteine ​​molar amount), stir, and obtain a solution with a mass concentration of 25-50%. S2. Under a high-purity nitrogen atmosphere, with stirring and at 60-85℃, the reaction is carried out for 10-24 h to obtain the product solution; S3. After removing the solvent from the product solution, dry to constant weight to obtain the modified castor oil product; The mass of component A is 50% - 72% of the sum of the masses of components A and B.

2. The modified castor oil-based polyurethane adhesive as described in claim 1, characterized in that, The molecular structural formula of the modified castor oil is as follows: Where ab is a C-C single bond, then R = If ab is a C=C double bond, R = H, and the number of double bonds in ab is ≤1.

3. The modified castor oil-based polyurethane adhesive as described in claim 1, characterized in that, The structural formula of the polyisocyanate is as follows: , , , , , , , , or At least one of them.

4. The modified castor oil-based polyurethane adhesive as described in claim 1, characterized in that, The polyisocyanate modifier is at least one of TDI trimer, HDI trimer, IPDI trimer, polyphenyl polymethylene polyisocyanate, PM-200, NT-8075, S-325 or S-310.

5. The modified castor oil-based polyurethane adhesive as described in claim 1, characterized in that, The initiator is at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, and azobiscyclohexylformitrile; the solvent is at least one of 1,4-dioxane, tetrahydrofuran, methyl ethyl ketone, butyl acetate, ethyl acetate, and toluene.

6. The modified castor oil-based polyurethane adhesive as described in claim 1, characterized in that, The dehydrating agent is at least one of p-toluenesulfonyl isocyanate, 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine, 3-butyl-2-(1-ethylpentyl)oxazolidine, and 2-methyl-2-ethyl-3-hydroxyethyl-1,3-oxazolidine.

7. The method for preparing the modified castor oil-based polyurethane adhesive according to any one of claims 1-6, characterized in that, The preparation method involves preparing the following components by weight: Component A: 30.0~50.0 parts of modified castor oil, 0.0~30.0 parts of refined castor oil; Component B: 30.0~50.0 parts of polyisocyanate or polyisocyanate modifier, 0.00~0.05 parts of dehydrating agent; At room temperature, component A is mixed, degassed under vacuum, and then filled into packaging and sealed. Component B is mixed, degassed under vacuum at room temperature, filled into packaging, and sealed to obtain polyurethane adhesive.

8. The application of a modified castor oil-based polyurethane adhesive as described in any one of claims 1-6 in the packaging process of new energy batteries.

Images