Single-component PUR easy-to-pull adhesive and preparation method thereof

Abstract

The invention provides a single-component PUR easy-to-pull adhesive and a preparation method thereof, and relates to the technical field of easy-to-pull adhesives. The single-component PUR easy-to-pull adhesive is prepared from the following raw materials in parts by mass, comprising the following components in parts by weight: 12 to 18 parts of polyether polyol, 15 to 25 parts of amorphous liquid saturated polyester polyol, 16 to 22 parts of crystalline polyester polyol, 20 to 30 parts of hydroxyl-terminated styrene-butadiene resin, 3 to 8 parts of magnesium strong powder, 0.05 to 0.15 part of an antioxidant, 0.02 to 0.05 part of a water removal agent, 2 to 6 parts of an isocyanate tripolymer, 7 to 13 parts of diisocyanate, 0.3 to 0.6 part of a coupling agent and 0.03 to 0.06 part of a catalyst. The single-component PUR easy-to-pull adhesive has the characteristics of high bonding strength, high impact resistance, high-temperature and high-humidity resistance, stretchability, no residue and the like, is particularly suitable for fixing modules such as batteries and the like, and can realize a residue-free removal function through stretching during replacement.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of easy-peel glue, and in particular to single-component PUR easy-peel glue and a preparation method thereof. BACKGROUND

[0002] With the rapid development of electronic products, the battery of each mobile phone manufacturer is fixedly used with an easy-peel glue tape specially designed for battery replacement of electronic equipment. The easy-peel glue tape has the characteristics of high adhesion, stretchability and no residue, and is mainly used for battery fixing and dismounting of precision equipment such as smart phones, which can significantly improve the maintenance efficiency and safety. However, the complex coating process and die cutting process of the easy-peel glue tape lead to an increase in cost.

[0003] Therefore, it is urgent to develop a new type of hot melt adhesive with high bonding strength, high impact resistance, high temperature and humidity resistance, stretchability, no residue, and improved assembly efficiency by using the high elasticity, wear resistance and aging resistance of polyurethane. SUMMARY

[0004] The application aims to provide single-component PUR easy-peel glue and a preparation method thereof to solve the above problems.

[0005] To achieve the above purpose, the first aspect of the application provides single-component PUR easy-peel glue, the raw materials of which include, by mass fraction: 12-18 parts of polyether polyol, 15-25 parts of non-crystalline liquid saturated polyester polyol, 16-22 parts of crystalline polyester polyol, 20-30 parts of hydroxyl-terminated styrene-butadiene resin, 3-8 parts of magnesium powder, 0.05-0.15 parts of antioxidant, 0.02-0.05 parts of water removal agent, 2-6 parts of isocyanate trimer, 7-13 parts of diisocyanate, 0.3-0.6 parts of coupling agent, and 0.03-0.06 parts of catalyst. The raw materials of the hydroxyl-terminated styrene-butadiene resin include styrene monomer, 1,4-butadiene monomer and 1,2-butadiene monomer.

[0006] Optionally, the polyether polyol includes at least one of propylene oxide glycol, ethylene oxide glycol and polytetrahydrofuran glycol. And / or, the number average molecular weight of the polyether polyol is 2000-6000.

[0007] Optionally, the non-crystalline liquid saturated polyester polyol includes at least one of polydiacid ethylene glycol, polydiacid propylene glycol, polydiacid butylene glycol and polydiacid 1.6 hexanediol. And / or, the number average molecular weight of the non-crystalline liquid saturated polyester polyol is 3000-6000.

[0008] Optionally, the crystalline polyester polyol includes polyethylene terephthalate and / or polybutylene terephthalate; And / or, the number average molecular weight of the crystalline polyester polyol is 3000-5000.

[0009] Optionally, the mass ratio of the styrene monomer, the 1,4-butadiene monomer, and the 1,2-butadiene monomer is 10-15:65-75:15-25; And / or, the magnesium oxide powder has a particle size of <15μm and a specific surface area of ​​8-15m². 2 / g, whiteness ≥90%.

[0010] Optionally, the molar ratio of NCO:OH in the isocyanate trimer is 0.25-0.3:1; And / or, the isocyanate trimer includes at least one of TDI trimer, HDI trimer and IPDI trimer; And / or, the molar ratio of NCO:OH in the diisocyanate is 1.9-2.7:1; And / or, the diisocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, and dicyclohexylmethane diisocyanate.

[0011] Optionally, the antioxidant includes at least one of 3,5-di-tert-butyl-4-hydroxyhydrocinnamate antioxidant, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester and 2,6-di-tert-butyl-p-cresol; And / or, the dehydrating agent comprises isocyanates with monofunctional groups; And / or, the coupling agent includes γ (2,3 glycidoxypropyltrimethoxysilane, γ At least one of (methacryloyloxy)propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-isocyanopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane; And / or, the catalyst comprises at least one of bismorpholino diethyl ether, dibutyltin dilaurate, and organobismuth catalysts.

[0012] A second aspect of this application provides a method for preparing the single-component PUR easy-pull adhesive, comprising: The polyether polyol, non-crystalline liquid saturated polyester polyol, crystalline polyester polyol, hydroxyl-terminated styrene-butadiene resin, magnesium oxide powder and antioxidant are first mixed and dehydrated to obtain a first mixture; Under a nitrogen atmosphere, the first mixture, the dehydrating agent, and the isocyanate trimer are subjected to a second mixing and a first reaction to obtain the first reactant; Under a nitrogen atmosphere, the first reactant and diisocyanate are mixed in a third and a second reaction to obtain the second reactant; Under a nitrogen atmosphere, the second reactant, coupling agent, and catalyst are mixed in a fourth process and reacted in a third process to obtain the single-component PUR easy-pull adhesive.

[0013] Optionally, the vacuum degree of the dehydration is ≤-0.1MPa, and the moisture content of the first mixture is <400ppm; And / or, the temperature of the first reaction is 100-110℃, and the time is 1-1.5h; And / or, the temperature of the second reaction is 100-110℃ and the time is 1-2h; And / or, the temperature of the third reaction is 105-115°C and the time is 25-35 min.

[0014] Optionally, the preparation of the hydroxyl-terminated styrene-butadiene resin includes: mixing tert-butanol, styrene monomer, 1,4-butadiene monomer, 1,2-butadiene monomer, hydrogen peroxide and n-thiol in a fifth mixture and a fourth reaction to obtain a fourth reactant; and mixing the fourth reactant with hydroquinone in a sixth mixture and a fifth reaction. The fourth reaction is carried out at a temperature of 128-135℃ for 4-5 hours. The fifth reaction is carried out at a temperature of 128-135℃ for 1-1.2 hours.

[0015] Compared with the prior art, the beneficial effects of this application include: The single-component PUR easy-open adhesive provided in this application has moderate viscosity, short open time, and smooth dispensing, making it suitable for various dispensing and spraying processes. It exhibits excellent adhesion to various plastics and metals, high impact resistance, high temperature and humidity resistance, stretchability, and leaves no residue. Furthermore, this single-component PUR easy-open adhesive is more convenient to use than traditional easy-open adhesive tapes, eliminating the need for complex coating and die-cutting processes. Assembly and fixation are achieved simply by preheating and spraying; disassembly is achieved by simply stretching the adhesive, resulting in a residue-free removable product. This single-component PUR easy-open adhesive features high bonding strength, high impact resistance, high temperature and humidity resistance, stretchability, and residue-free characteristics, making it particularly suitable for fixing modules such as batteries. Replacement is achieved through simple stretching, resulting in residue-free removal.

[0016] The method for preparing the single-component PUR easy-pull adhesive provided in this application is simple to operate and the raw materials are readily available. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0018] Figure 1 This is a physical image of the single-component PUR easy-pull adhesive provided in Example 1. Detailed Implementation

[0019] First, the solution provided in this application will be explained in more detail as follows: The first aspect of this application provides a one-component PUR easy-pull adhesive, the raw materials of which, by weight, include: 12-18 parts of polyether polyol, 15-25 parts of amorphous liquid saturated polyester polyol, 16-22 parts of crystalline polyester polyol, 20-30 parts of hydroxyl-terminated styrene-butadiene resin, 3-8 parts of magnesium oxide powder, 0.05-0.15 parts of antioxidant, 0.02-0.05 parts of dehydrating agent, 2-6 parts of isocyanate trimer, 7-13 parts of diisocyanate, 0.3-0.6 parts of coupling agent, and 0.03-0.06 parts of catalyst; Optionally, the polyether polyol can be any value between 12, 13, 14, 15, 16, 17, 18 parts or 12-18 parts; the amorphous liquid saturated polyester polyol can be any value between 15, 20, 25, 30, 35 parts or 15-35 parts; the crystalline polyester polyol can be any value between 16, 17, 18, 18, 20, 21, 22 parts or 16-22 parts; the hydroxyl-terminated styrene-butadiene resin can be any value between 20, 25, 30 parts or 20-30 parts; the magnesium oxide powder can be any value between 3, 4, 5, 6, 7, 8 parts or 3-8 parts; and the antioxidant can be 0.05 parts or 0. The following amounts are allowed: 1 part, 0.15 parts, or any value between 0.05 and 0.15 parts; the dehydrating agent can be any value between 0.02 parts, 0.03 parts, 0.04 parts, 0.05 parts, or any value between 0.02 and 0.05 parts; the isocyanate trimer can be any value between 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, or any value between 2 and 6 parts; the diisocyanate can be any value between 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, or any value between 7 and 13 parts; the coupling agent can be any value between 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, or any value between 0.3 and 0.6 parts; and the catalyst can be any value between 0.03 parts, 0.04 parts, 0.05 parts, 0.06 parts, or any value between 0.03 and 0.06 parts. It is important to note that this application uses high-molecular-weight polyether polyols to provide soft segments of the molecular chain, determining the basic flexibility and hydrolysis resistance of the colloid; non-crystalline liquid saturated polyester polyols are used to provide cohesive strength, balancing flexibility and rigidity; crystalline polyester polyols are selected to utilize their crystallization properties to provide initial curing rate and cohesive strength; hydroxyl-terminated styrene-butadiene resins are selected, utilizing the reaction between hydroxyl-terminated styrene-butadiene resins and isocyanates to form a three-dimensional network structure of elastomer, improving the toughness, resilience, and elongation of the adhesive; magnesium oxide powder is selected and added to the adhesive to transform its planar structure into a three-dimensional structure, improving the adhesive's abrasion resistance, toughness, and crack resistance; antioxidants are selected to improve the adhesive's aging resistance; and other additives are selected to improve the adhesive's aging resistance. The water-based formulation addresses the issue of moisture affecting the viscosity and storage stability of raw materials. Isocyanate trimer + diisocyanate introduces a branched structure in the trimer and constructs a main cross-linking network with the diisocyanate, forming a rigid-flexible three-dimensional network structure that improves the toughness and resilience of the cured adhesive. A coupling agent improves interfacial bonding, enhances resistance to damp heat aging, and increases the curing rate. A catalyst alters the chemical reaction rate while maintaining its own mass and chemical properties before and after the reaction. The resulting single-component PUR water-based adhesive replaces easy-pull adhesive tape, eliminating the need for complex coating and die-cutting processes. Customers only need to preheat the adhesive or spray it for assembly and fixation; disassembly is as simple as stretching the adhesive to achieve a residue-free, removable finish.

[0020] The raw materials in the hydroxyl-terminated styrene-butadiene resin include styrene monomer, 1,4-butadiene monomer and 1,2-butadiene monomer.

[0021] In some embodiments, the polyether polyol includes at least one of propylene oxide glycol, ethylene oxide glycol, and polytetrahydrofuran glycol; And / or, the number average molecular weight of the polyether polyol is 2000-6000.

[0022] Optionally, the number average molecular weight of the polyether polyol can be 2000, 3000, 4000, 5000, 6000 or any value between 2000 and 6000.

[0023] It is important to note that the higher the molecular weight of the polyether polyol, the better the flexibility and elongation of the adhesive. Preferably, the number average molecular weight of the polyether polyol is 4000.

[0024] In some embodiments, the amorphous liquid saturated polyester polyol includes at least one of polyethylene glycol dicarboxylate, propylene glycol dicarboxylate, butylene glycol dicarboxylate, and 1,6-hexanediol dicarboxylate. And / or, the number average molecular weight of the amorphous liquid saturated polyester polyol is 3000-6000.

[0025] Optionally, the number average molecular weight of the amorphous liquid saturated polyester polyol can be any value between 3000, 4000, 5000, 6000 or 3000-6000.

[0026] It should be noted that the larger the molecular weight of the polyester resin, the better the flexibility of the adhesive and the longer the elongation.

[0027] Preferably, the number average molecular weight of the non-crystalline liquid saturated polyester polyol is 5500.

[0028] In some embodiments, the crystalline polyester polyol includes at least one of polyethylene terephthalate and polybutylene terephthalate; And / or, the number average molecular weight of the crystalline polyester polyol is 3000-5000.

[0029] Optionally, the number average molecular weight of the crystalline polyester polyol can be 3000, 4000, 5000 or any value between 3000 and 5000.

[0030] Preferably, the number average molecular weight of the crystalline polyester polyol is 3500.

[0031] In some embodiments, the mass ratio of the styrene monomer, the 1,4-butadiene monomer, and the 1,2-butadiene monomer is 10-15:65-75:15-25; Optionally, the mass ratio of styrene monomer, 1,4-butadiene monomer and 1,2-butadiene monomer can be any value between 10:65:25, 15:65:20, 10:70:20, 10:75:15 or 10-15:65-75:15-25; Preferably, the mass ratio of styrene monomer, 1,4-butadiene monomer and 1,2-butadiene monomer is 10:70:20; And / or, the magnesium oxide powder has a particle size of <15μm and a specific surface area of ​​8-15m². 2 / g, whiteness ≥90%.

[0032] Optionally, the particle size of the magnesium oxide powder can be any value of 1μm, 3μm, 6μm, 9μm, 12μm, 14μm or <15μm, and the specific surface area can be 8 m². 2 / g、9 m 2 / g、12 m 2 / g、15 m 2 / g or 8-15 mg 2 Any value between / g, the whiteness can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or any value ≥90%.

[0033] In some embodiments, the molar ratio of NCO:OH in the isocyanate trimer is 0.25-0.3:1; Optionally, the molar ratio of NCO:OH in the isocyanate trimer can be 0.25:1, 0.26:1, 0.27:1, 0.28:1, 0.29:1, 0.3:1, or any value between 0.25 and 0.3:1; And / or, the isocyanate trimer includes at least one of TDI trimer, HDI trimer and IPDI trimer; Preferably, the isocyanate trimer includes TDI trimer; And / or, the molar ratio of NCO:OH in the diisocyanate is 1.9-2.7:1; Optionally, the molar ratio of NCO:OH in the diisocyanate can be any value between 1.9:1, 2:1, 2.2:1, 2.4:1, 2.5:1, 2.7:1, or 1.9:2.7:1; And / or, the diisocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, and dicyclohexylmethane diisocyanate.

[0034] Preferably, the diisocyanate includes diphenylmethane diisocyanate.

[0035] In some embodiments, the antioxidant includes at least one of 3,5-di-tert-butyl-4-hydroxyhydrocinnamate antioxidant, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester and 2,6-di-tert-butyl-p-cresol. Preferably, the antioxidant includes 3,5-di-tert-butyl-4-hydroxyhydrocinnamate antioxidant.

[0036] And / or, the dehydrating agent comprises isocyanates with monofunctional groups; And / or, the coupling agent includes γ (2,3 glycidoxypropyltrimethoxysilane, γ At least one of (methacryloyloxy)propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-isocyanopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane; Preferably, the coupling agent includes γ-mercaptopropyltrimethoxysilane; And / or, the catalyst comprises at least one of bismorpholino diethyl ether, dibutyltin dilaurate, and organobismuth catalysts.

[0037] Preferably, the catalyst comprises bismorpholino diethyl ether.

[0038] A second aspect of this application provides a method for preparing the single-component PUR easy-pull adhesive, comprising: The polyether polyol, non-crystalline liquid saturated polyester polyol, crystalline polyester polyol, hydroxyl-terminated styrene-butadiene resin, magnesium oxide powder and antioxidant are first mixed and dehydrated to obtain a first mixture; Under a nitrogen atmosphere, the first mixture, the dehydrating agent, and the isocyanate trimer are subjected to a second mixing and a first reaction to obtain the first reactant; Under a nitrogen atmosphere, the first reactant and diisocyanate are mixed in a third and a second reaction to obtain the second reactant; Under a nitrogen atmosphere, the second reactant, coupling agent, and catalyst are mixed in a fourth process and reacted in a third process to obtain the single-component PUR easy-pull adhesive.

[0039] In some embodiments, the vacuum degree of the dehydration is ≤-0.1MPa, and the moisture content of the first mixture is <400ppm; Optionally, the vacuum degree for dehydration can be any value of -0.01 MPa, -0.05 MPa, -0.1 MPa or ≤-0.1 MPa, and the moisture content of the first mixture can be any value of 100 ppm, 200 ppm, 300 ppm, 399 ppm or <400 ppm; And / or, the temperature of the first reaction is 100-110℃, and the time is 1-1.5h; Optionally, the temperature of the first reaction can be any value between 100℃, 105℃, 110℃ or 100-110℃, and the time can be any value between 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h or 1-1.5h; And / or, the temperature of the second reaction is 100-110℃ and the time is 1-2h; Optionally, the temperature of the second reaction can be any value between 100℃, 105℃, 110℃ or 100-110℃, and the time can be any value between 1h, 1.5h, 2h or 1-2h. And / or, the temperature of the third reaction is 105-115°C and the time is 25-35 min.

[0040] Optionally, the temperature of the third reaction can be any value between 105℃, 110℃, 115℃ or 105-115℃, and the time can be any value between 25min, 30min, 35min or 25-35min.

[0041] In some embodiments, the preparation of the hydroxyl-terminated styrene-butadiene resin includes: mixing tert-butanol, styrene monomer, 1,4-butadiene monomer, 1,2-butadiene monomer, hydrogen peroxide and n-thiol in a fifth mixture and a fourth reaction to obtain a fourth reactant; and mixing the fourth reactant with hydroquinone in a sixth mixture and a fifth reaction. It is important to note that styrene provides rigidity and strength, while butadiene imparts flexibility and elasticity. Hydroxyl-terminated styrene-butadiene (-OH) can react directly with isocyanates (-NCO) to form a three-dimensional network elastomer, improving the adhesive's toughness, resilience, and elongation. The fourth reaction is carried out at a temperature of 128-135℃ for 4-5 hours. Optionally, the temperature of the fourth reaction can be any value between 128℃, 129℃, 130℃, 131℃, 132℃, 133℃, 134℃, 135℃ or 128-135℃, and the time can be any value between 4h, 4.5h, 5h or 4-5h. The fifth reaction is carried out at a temperature of 128-135℃ for 1-1.2 hours.

[0042] Optionally, the temperature of the fifth reaction can be any value between 128℃, 129℃, 130℃, 131℃, 132℃, 133℃, 134℃, 135℃ or 128-135℃, and the time can be any value between 1h, 1.1h, 1.2h or 1-1.2h.

[0043] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0044] Example 1 The first aspect of this embodiment provides a single-component PUR easy-pull adhesive, the raw materials of which, by weight, include: 15 parts of polyether polyol (polytetrahydrofuran diol), 20 parts of non-crystalline liquid saturated polyester polyol (polyethylene diacid glycol, number average molecular weight of 5500), 19 parts of crystalline polyester polyol (polyethylene terephthalate, number average molecular weight of 3500), 25 parts of hydroxyl-terminated styrene-butadiene resin, and magnesium oxide powder (particle size <15μm, specific surface area of ​​10m²). 2 / g, whiteness ≥90%) 3 parts, antioxidant (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) 0.1 parts, dehydrating agent (monofunctional isocyanate AdditiveTI) 0.05 parts, isocyanate trimer (HDI trimer, NCO:OH molar ratio of 0.3:1) 3.2 parts, diisocyanate (diphenylmethane diisocyanate, NCO:OH molar ratio of 2.1:1) 9 parts, coupling agent 0.45 parts (γ-mercaptopropyltrimethoxysilane), catalyst (bismorpholinodiethyl ether) 0.05 parts.

[0045] The raw materials for the hydroxyl-terminated styrene-butadiene resin include 90 parts of tert-butanol, 10 parts of styrene, 70 parts of 1,4-butadiene, 20 parts of 1,2-butadiene, 20.25 parts of hydrogen peroxide, 1.625 parts of n-thiol, and 3.125 parts of hydroquinone.

[0046] In addition, a second aspect of this application provides a method for preparing a one-component PUR easy-pull adhesive, the specific steps of which are as follows: S1. Preparation of hydroxyl-terminated styrene-butadiene resin: Weigh the raw materials by weight, add 90 parts of tert-butanol to a high-pressure reactor, slowly heat to 85°C, add 10 parts of styrene monomer, 70 parts of 1,4-butadiene monomer, 20 parts of 1,2-butadiene monomer, 20.25 parts of hydrogen peroxide and 1.625 parts of n-thiol, start stirring and heat to 135°C to react for 4 hours, add 3.125 parts of hydroquinone and react for 1 hour, centrifuge, wash with water and remove water to obtain hydroxyl-terminated styrene-butadiene resin (hydroxyl-terminated styrene-butadiene resin 1) for later use; S2. Mix polytetrahydrofuran glycol, polyethylene glycol dicarboxylate, polyethylene terephthalate, hydroxyl-terminated styrene-butadiene resin 1, magnesium oxide powder and 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, start stirring and heat to 135°C, dehydrate under vacuum of ≤-0.1MPa until the moisture content is <400ppm, and cool to 100°C to obtain a mixture; S3. Under nitrogen protection, add AdditiveTI and HDI trimer to the mixture, stir for 15 min, then heat to 110℃ and react for 1 h. S4. Under nitrogen protection, continue to add diphenylmethane diisocyanate and react for 1.5 h; S5. Under nitrogen protection, continue to add γ-mercaptopropyltrimethoxysilane and bismorpholinodiethyl ether, stir for 30 minutes, and then discharge the material and seal it to obtain single-component PUR easy-pull adhesive.

[0047] The actual product of this one-component PUR easy-pull adhesive is as follows: Figure 1 As shown.

[0048] Example 2-3 This application also provides Examples 2 and 3, which differ from Example 1 in that the amount of raw material used for the hydroxyl-terminated styrene-butadiene resin is different, but the preparation method is the same as that in Example 1. The specific amount of raw material used for the hydroxyl-terminated styrene-butadiene resin is shown in Table 1 (in parts).

[0049] Table 1. Raw material usage of hydroxyl-terminated styrene-butadiene resin

[0050] Comparative Example 1 The difference from Example 1 is that HDI trimer is not added, and the amount of diisocyanate (diphenylmethane diisocyanate) is 12.5 parts.

[0051] Comparative Example 2 The difference from Example 2 is that the hydroxyl-terminated styrene-butadiene resin was replaced with maleic anhydride styrene-butadiene copolymer (purchased from Kraton FG1901, USA), the HDI trimer was 2.1 parts, and the diphenylmethane diisocyanate was 6 parts.

[0052] Comparative Example 3 The difference from Example 3 is that no magnesium strengthening powder is added.

[0053] Comparative Example 4 The difference from Example 1 is that no hydroxyl-terminated styrene-butadiene resin is added.

[0054] Comparative Example 5 The difference from Example 1 is that no non-crystalline liquid saturated polyester polyol is added.

[0055] Comparative Example 6 The difference from Example 1 is that no crystalline polyester polyol is added.

[0056] Comparative Example 7 The difference from Example 1 is that the amount of raw materials is different, specifically: 20 parts of polyether polyol, 26 parts of non-crystalline liquid saturated polyester polyol, 23 parts of crystalline polyester polyol, 35 parts of hydroxyl-terminated styrene-butadiene resin, 2 parts of magnesium oxide powder, 0.2 parts of antioxidant, 0.1 parts of dehydrating agent, 7 parts of isocyanate trimer, 14 parts of diisocyanate, 0.6 parts of coupling agent, and 0.1 parts of catalyst.

[0057] To further verify that the single-component PUR easy-pull adhesive provided in this application has good adhesion, high impact resistance, high and low temperature resistance, stretchability, and no residue, the single-component PUR easy-pull adhesives provided in the above embodiments and comparative examples were subjected to performance testing. The specific test results are shown in Table 2.

[0058] The testing standards are as follows: The sample was prepared by spraying adhesive at room temperature and cured at room temperature for 24 hours before the tensile strength was tested. The test method for elongation at break is GB / T 528-2019; the test method for resilience is GB / T 1681-2018. The DuPont impact test method is: ASTM-D2794; Removal test method: After melting the glue, apply the glue to the AL surface using the equipment, attach the aluminum-plastic film, and let it stand at room temperature for 24 hours. Then, use a tensile testing machine to remove the film at angles of 0°, 45°, and 90° and a speed of 300 mm / min to observe the removal effect and mechanical properties.

[0059] Table 2 Performance Tests

[0060] analyze: As can be seen from the above tests, the difference between Example 1 and Comparative Example 1 is that Example 1 uses isocyanate trimer in the same molar ratio to replace part of the isocyanate dimer. The data in the table shows that the elongation, DuPont impact and removability tests of Example 1 are better than those of Comparative Example 1. As can be seen from the above analysis, using isocyanate trimer to replace isocyanate dimer improves the toughness of the adhesive by connecting the linear structure with a partial network structure.

[0061] The difference between Example 2 and Comparative Example 2 is that Example 2 uses hydroxyl-terminated styrene-butadiene resin, while Comparative Example 2 uses maleic anhydride styrene-butadiene copolymer. As can be seen from the data in the table, the elongation, resilience, DuPont impact and removability test results of Example 2 are better than those of Comparative Example 2. The above analysis shows that the use of hydroxyl-terminated styrene-butadiene resin to replace maleic anhydride styrene-butadiene copolymer has good compatibility between the two, making it branch from a linear structure into a partial network structure, thereby improving the toughness and resilience of the adhesive. The difference between Example 3 and Comparative Example 3 is that Example 3 used magnesium powder, while Comparative Example 3 did not add magnesium powder. The data in the table show that the removal effect of Example 3 is better than that of Comparative Example 3.

[0062] The difference between Comparative Example 4 and Example 1 is that no hydroxyl-terminated styrene-butadiene resin is added. In Comparative Example 4, without hydroxyl-terminated styrene-butadiene resin, the entire soft segment system relies only on traditional multi-component systems (PTMEG, polyester, etc.), lacking the contribution of highly elastic long chains. The flexibility of the molecular chains decreases, and the chain segment movement ability is limited. Under the action of external forces, it cannot dissipate energy through chain slip or entropic elasticity, and can only release energy through brittle fracture.

[0063] The difference between Comparative Example 5 and Example 1 is that no non-crystalline liquid saturated polyester polyol was added. The absence of this polyol caused the material to become brittle, its resilience to decrease by 30%, and it broke at both 45° and 90° removal, indicating insufficient flexibility reserve.

[0064] The difference between Comparative Example 6 and Example 1 is that without the addition of crystalline polyester polyol, the initial strength and modulus support are lost: the crystalline region acts as a physical crosslinking point, the tensile strength drops sharply, and all peel tests show breakage, indicating a lack of sufficient structural support.

[0065] The difference between Comparative Example 7 and the actual example is the amount used, which leads to an imbalance in the NCO / OH ratio and causes gelation. This shows that the NCO / OH ratio must be strictly controlled within an appropriate range.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0067] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A single-component PUR easy-pull adhesive, characterized in that, Its raw materials, by weight, include: 12-18 parts of polyether polyol, 15-25 parts of amorphous liquid saturated polyester polyol, 16-22 parts of crystalline polyester polyol, 20-30 parts of hydroxyl-terminated styrene-butadiene resin, 3-8 parts of magnesium oxide powder, 0.05-0.15 parts of antioxidant, 0.02-0.05 parts of dehydrating agent, 2-6 parts of isocyanate trimer, 7-13 parts of diisocyanate, 0.3-0.6 parts of coupling agent, and 0.03-0.06 parts of catalyst; The raw materials in the hydroxyl-terminated styrene-butadiene resin include styrene monomer, 1,4-butadiene monomer and 1,2-butadiene monomer.

2. The single-component PUR easy-pull adhesive according to claim 1, characterized in that, The polyether polyol includes at least one of propylene oxide glycol, ethylene oxide glycol, and polytetrahydrofuran glycol. And / or, the number average molecular weight of the polyether polyol is 2000-6000.

3. The single-component PUR easy-pull adhesive according to claim 1, characterized in that, The amorphous liquid saturated polyester polyol includes at least one of polyethylene glycol dicarboxylate, propylene glycol dicarboxylate, butylene glycol dicarboxylate, and 1,6-hexanediol dicarboxylate. And / or, the number average molecular weight of the amorphous liquid saturated polyester polyol is 3000-6000.

4. The single-component PUR easy-pull adhesive according to claim 1, characterized in that, The crystalline polyester polyols include polyethylene terephthalate and / or polybutylene terephthalate; And / or, the number average molecular weight of the crystalline polyester polyol is 3000-5000.

5. The single-component PUR easy-pull adhesive according to claim 1, characterized in that, The mass ratio of the styrene monomer, the 1,4-butadiene monomer, and the 1,2-butadiene monomer is 10-15:65-75:15-25. And / or, the magnesium oxide powder has a particle size of <15μm and a specific surface area of ​​8-15m². 2 / g, whiteness ≥90%.

6. The single-component PUR easy-pull adhesive according to claim 1, characterized in that, The molar ratio of NCO:OH in the isocyanate trimer is 0.25-0.3:1; And / or, the isocyanate trimer includes at least one of TDI trimer, HDI trimer and IPDI trimer; And / or, the molar ratio of NCO:OH in the diisocyanate is 1.9-2.7:1; And / or, the diisocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, and dicyclohexylmethane diisocyanate.

7. The single-component PUR easy-pull adhesive according to any one of claims 1-6, characterized in that, The antioxidant includes at least one of 3,5-di-tert-butyl-4-hydroxyhydrocinnamate antioxidant, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester and 2,6-di-tert-butyl-p-cresol; And / or, the dehydrating agent comprises isocyanates with monofunctional groups; And / or, the coupling agent includes γ (2,3 glycidoxypropyltrimethoxysilane, γ At least one of (methacryloyloxy)propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-isocyanopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane; And / or, the catalyst comprises at least one of bismorpholino diethyl ether, dibutyltin dilaurate, and organobismuth catalysts.

8. A method for preparing a single-component PUR easy-pull adhesive according to any one of claims 1-7, characterized in that, include: The polyether polyol, non-crystalline liquid saturated polyester polyol, crystalline polyester polyol, hydroxyl-terminated styrene-butadiene resin, magnesium oxide powder and antioxidant are first mixed and dehydrated to obtain a first mixture; Under a nitrogen atmosphere, the first mixture, the dehydrating agent, and the isocyanate trimer are subjected to a second mixing and a first reaction to obtain the first reactant; Under a nitrogen atmosphere, the first reactant and diisocyanate are mixed in a third and a second reaction to obtain the second reactant; Under a nitrogen atmosphere, the second reactant, coupling agent, and catalyst are mixed in a fourth process and reacted in a third process to obtain the single-component PUR easy-pull adhesive.

9. The method for preparing a single-component PUR easy-pull adhesive according to claim 8, characterized in that, The vacuum degree of the dehydration is ≤-0.1MPa, and the moisture content of the first mixture is <400ppm; And / or, the temperature of the first reaction is 100-110℃, and the time is 1-1.5h; And / or, the temperature of the second reaction is 100-110℃ and the time is 1-2h; And / or, the temperature of the third reaction is 105-115°C and the time is 25-35 min.

10. The method for preparing a single-component PUR easy-pull adhesive according to claim 8 or 9, characterized in that, The preparation of the hydroxyl-terminated styrene-butadiene resin includes: mixing tert-butanol, styrene monomer, 1,4-butadiene monomer, 1,2-butadiene monomer, hydrogen peroxide and n-thiol in a fifth mixture and a fourth reaction to obtain a fourth reactant; and mixing the fourth reactant with hydroquinone in a sixth mixture and a fifth reaction. The fourth reaction is carried out at a temperature of 128-135℃ for 4-5 hours. The fifth reaction is carried out at a temperature of 128-135℃ for 1-1.2 hours.

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