Polyurethane-pressure-sensitive adhesive composite structural adhesive and preparation method thereof

Abstract

The invention discloses a polyurethane-pressure-sensitive adhesive composite structural adhesive and a preparation method thereof, and relates to the field of adhesive preparation. According to the invention, the polyurethane and the pressure-sensitive adhesive are compounded to prepare the polyurethane-pressure-sensitive adhesive composite structural adhesive; during compounding, the polyurethane and the pressure-sensitive adhesive can further react, so that the compounding effect is enhanced; the polyurethane comprises polyurethane subjected to chain extension by diamine; the pressure-sensitive adhesive comprises an acrylate resin modified pressure-sensitive adhesive. The polyurethane-pressure-sensitive adhesive composite structural adhesive prepared by the preparation method disclosed by the invention is stronger in cohesive force and adhesive force, simple in preparation process and wide in application value.

Description

Technical Field

[0001] The invention relates to the field of adhesive preparation, in particular to a polyurethane-pressure sensitive adhesive composite structural adhesive and a preparation method thereof. Background Art

[0002] In modern industrial manufacturing and daily life, structural adhesives are widely used in the connection of various materials due to their excellent bonding properties. Traditional structural adhesives mainly include polyurethane structural adhesives, epoxy resin structural adhesives, acrylate structural adhesives, etc., which have good mechanical strength and chemical resistance. However, with the development of science and technology and changes in market demand, the performance requirements for structural adhesives are also constantly increasing, especially in the fields of automobile manufacturing, electronic products, construction industry, etc., which put forward higher requirements for the flexibility, temperature resistance and weather resistance of structural adhesives.

[0003] Polyurethane is a polymer material with excellent abrasion resistance, elasticity and chemical resistance. Pressure-sensitive adhesive is a material that can achieve bonding under slight pressure. It is easy to apply and has a fast bonding speed.

[0004] At present, the common polyurethane structural adhesives on the market are those obtained by simply mixing two components, but there are few structural adhesives prepared by further reacting polyurethane and pressure-sensitive adhesives. This limits the application scope and further improvement of the performance of both to a certain extent.

[0005] A Chinese patent with publication number CN 112608707A discloses a two-component polyurethane structural adhesive and a preparation method thereof. The raw materials for preparing the two-component polyurethane structural adhesive include component A and component B, component A includes castor oil polyol, phosphorus trichloride modified polyether polyol, aromatic polyester polyol, a first thermal conductive filler, a first flame retardant filler and a first auxiliary agent, and component B includes isocyanate-terminated polyurethane prepolymer, polymethylene polyphenyl polyisocyanate, a second thermal conductive filler, a second flame retardant filler and a second auxiliary agent. The two-component polyurethane structural adhesive prepared by mixing components A and B in a certain volume ratio has low density, good flame retardant and thermal conductivity, high temperature shear strength and low temperature curing performance. However, it does not further react polyurethane with pressure-sensitive adhesive to prepare structural adhesive, and the formula composition is very different, and there is still a lot of room for improvement in properties such as adhesion. Summary of the invention

[0006] In summary, the present invention aims to provide a polyurethane-pressure-sensitive adhesive composite structural adhesive, which achieves the complementarity of the performance of the two materials through specific formula design and process optimization, maintaining the excellent properties of polyurethane and giving the structural adhesive better bonding performance. The development of this new structural adhesive will bring more efficient and reliable bonding solutions to related application fields and meet the market demand for high-performance structural adhesives.

[0007] In order to achieve the above objectives, this application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a polyurethane-pressure-sensitive adhesive composite structural adhesive, wherein the polyurethane-pressure-sensitive adhesive composite structural adhesive is obtained by subjecting polyurethane and pressure-sensitive adhesive to a composite reaction; the polyurethane comprises a diamine-chain-extended polyurethane; and the pressure-sensitive adhesive comprises an acrylate resin-modified pressure-sensitive adhesive.

[0009] In a second aspect, the present application provides a method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive, the method for preparing the polyurethane-pressure-sensitive adhesive composite structural adhesive comprising:

[0010] Weigh the solvent, diamine-extended polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0011] Then, the temperature is raised to 150-160°C under nitrogen protection, and then a condensation agent is added to the reaction kettle, followed by stirring and reacting at this temperature for 4-6 hours;

[0012] Finally, the temperature is lowered to 50-60°C, stirring is continued for 0.5-1h, and then the material is discharged to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive.

[0013] Beneficial technical effects:

[0014] The polyurethane-pressure-sensitive adhesive composite structural adhesive prepared in the present application is specifically obtained by a composite reaction of a polyurethane extended by diamine and a pressure-sensitive adhesive modified by an acrylate resin. The polyurethane extended by diamine contains a large number of -NH- groups, in which the nitrogen atom carries a lone pair of electrons and has a strong nucleophilicity; while the acrylate resin modified pressure-sensitive adhesive contains a large number of epoxy groups, in which the oxygen atom has a large electronegativity, so that the carbon atoms on the ring carry a partial positive charge, and are thus easily attacked by nucleophilic reagents. The above two groups can therefore undergo a chemical reaction under certain conditions, and the -NH- group acts as a nucleophilic reagent to attack the carbon atoms on the epoxy group, causing the epoxy group to open its ring, thereby allowing the polyurethane and the pressure-sensitive adhesive to be compounded together through chemical bonds in terms of microstructure, achieving an effect higher than that of compounding by simple physical means.

[0015] The polyurethane-pressure-sensitive adhesive composite structural adhesive prepared in the present application also contains a large number of oxygen atoms and nitrogen atoms, so it can produce stronger cohesive force, and can form more hydrogen bonds with groups such as hydroxyl groups on the surface of the bonded material, thereby greatly enhancing the bonding force.

[0016] The polyurethane-pressure-sensitive adhesive composite structural adhesive prepared in the present application has a simple preparation process, realizes the complementary performance of the two materials, polyurethane and pressure-sensitive adhesive, maintains the excellent properties of polyurethane, and gives the structural adhesive better bonding performance, which has important practical value and broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the diamine-extended polyurethane.

[0018] Figure 2 It is a schematic diagram of the structure of the acrylic resin modified pressure-sensitive adhesive.

[0019] Figure 3 It is a schematic diagram of the composite reaction of the polyurethane and the pressure-sensitive adhesive.

[0020] Figure 4 It is a schematic diagram of the structure of the polyurethane-pressure-sensitive adhesive composite structural adhesive prepared in Example 1.

[0021] Figure 5 It is a schematic diagram of the preparation process of the polyurethane-pressure sensitive adhesive composite structural adhesive. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application is further described in detail below in conjunction with the embodiments. However, this should not be understood as the scope of the present application being limited to the following examples. Without departing from the above-mentioned method ideas of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0023] In this application, the terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit the application.

[0024] As used in this application and the appended claims, the singular forms "for," "or," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0025] In a first aspect, the present application provides a polyurethane-pressure-sensitive adhesive composite structural adhesive, wherein the polyurethane-pressure-sensitive adhesive composite structural adhesive is obtained by subjecting polyurethane and pressure-sensitive adhesive to a composite reaction; the polyurethane comprises a diamine-chain-extended polyurethane; and the pressure-sensitive adhesive comprises an acrylate resin-modified pressure-sensitive adhesive.

[0026] Optionally, the diamine-extended polyurethane may be represented as Figure 1 The structure shown includes:

[0027]

[0028] Wherein: R and R' represent organic groups, including aliphatic or aromatic groups.

[0029] Optionally, the preparation method of the diamine chain-extended polyurethane comprises:

[0030] Weigh diisocyanate, polyethylene glycol and solvent separately and add them into a glass flask;

[0031] Then, the temperature is raised to 90-100° C. under nitrogen protection, and then a catalyst is added to the glass flask, followed by stirring and reacting at this temperature for 4-6 hours to obtain a prepolymer;

[0032] Then, the diamine chain extender is added to the prepolymer, and the reaction is continued at 90 to 100° C. with stirring for 18 to 22 hours;

[0033] Finally, the temperature is lowered to 50-60°C, and the material is discharged after stirring for 2-3 hours to obtain a diamine-chain-extended polyurethane.

[0034] Optionally, the general formula of the diisocyanate is: O=C=NRN=O=C; wherein: R represents an organic group, including an aliphatic or aromatic group.

[0035] Optionally, the solvent comprises xylene.

[0036] Optionally, the catalyst includes one or more of organic tin compounds and organic bismuth compounds.

[0037] Optionally, the general formula of the diamine chain extender is: NH2-R'-NH2; wherein: R' represents an organic group, including an aliphatic or aromatic group.

[0038] Optionally, the mass ratio of the diisocyanate, polyethylene glycol, solvent, catalyst and diamine chain extender is (15-25): (20-30): (30-40): (2-5): (20-30).

[0039] Optionally, the acrylate resin modified pressure sensitive adhesive can be expressed as Figure 2 The structure shown includes:

[0040]

[0041] R" represents a substituent on the vinyl group, including hydrogen (H), methyl (-CH 3 ), ethyl (-CH2CH3).

[0042] Optionally, the preparation method of the acrylic resin modified pressure-sensitive adhesive includes:

[0043] Weigh the acrylic acid ester monomer and solvent respectively, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0044] Then the temperature is raised to 180-200°C, a chain transfer agent and an initiator are added to the glass flask, and the mixture is refluxed and kept warm for 4-6 hours under nitrogen protection;

[0045] Finally, the temperature is lowered to 50-60°C and the material is discharged to obtain the acrylic resin modified pressure-sensitive adhesive.

[0046] Optionally, the general formula of the acrylate monomer is:

[0047]

[0048] Where: R" represents a substituent on the vinyl group, including hydrogen (H), methyl (-CH 3 ), ethyl (-CH2CH3).

[0049] Optionally, the solvent comprises xylene.

[0050] Optionally, the chain transfer agent includes one or more of a mercaptan chain transfer agent and an alkylphenol chain transfer agent.

[0051] Optionally, the initiator includes one or more of an azo initiator and an acyl peroxide.

[0052] Optionally, the mass ratio of the acrylic acid ester monomer, the solvent, the chain transfer agent and the initiator is (45-50): (45-50): (2-5): (2-5).

[0053] Optionally, the composite reaction of the polyurethane and the pressure-sensitive adhesive is as follows: Figure 3 As shown, including:

[0054]

[0055] In a second aspect, the present application provides a method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive, the method for preparing the polyurethane-pressure-sensitive adhesive composite structural adhesive comprising:

[0056] Weigh the solvent, diamine-extended polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0057] Then, the temperature is raised to 150-160°C under nitrogen protection, and then a condensation agent is added to the reaction kettle, followed by stirring and reacting at this temperature for 4-6 hours;

[0058] Finally, the temperature is lowered to 50-60°C, stirring is continued for 0.5-1h, and then the material is discharged to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive.

[0059] Optionally, the solvent comprises xylene.

[0060] Optionally, the condensing agent includes an organic phosphorus condensing agent.

[0061] Optionally, the mass ratio of the solvent, the diamine-extended polyurethane, the acrylate resin-modified pressure-sensitive adhesive, and the condensation agent is (30-40): (25-30): (35-40): (2-5).

[0062] The sources of experimental raw materials used in the present invention are as follows:

[0063] Diisocyanate: Shanghai MacLean Biochemical Technology Co., Ltd.;

[0064] Polyethylene glycol: Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0065] Solvent: Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0066] Catalyst: Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0067] Diamine: Shanghai MacLean Biochemical Technology Co., Ltd.;

[0068] Ethylene glycol: Shanghai MacLean Biochemical Technology Co., Ltd.;

[0069] Acrylate monomer: Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0070] Chain transfer agent: Shanghai MacLean Biochemical Technology Co., Ltd.;

[0071] Initiator: Shanghai MacLean Biochemical Technology Co., Ltd.;

[0072] Condensation agent: Shanghai MacLean Biochemical Technology Co., Ltd.

[0073] The following will specifically describe a polyurethane-pressure-sensitive adhesive composite structural adhesive and a preparation method thereof provided by the present application in combination with different examples.

[0074] Embodiment 1:

[0075] like Figure 5 As shown, a method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive comprises the following steps:

[0076] 1. Weigh toluene diisocyanate, polyethylene glycol and xylene respectively and add them into a glass flask;

[0077] 2. Then, the temperature was raised to 95°C under nitrogen protection, and then dibutyltin dilaurate was added to the glass flask, followed by stirring and reacting at this temperature for 5 hours to obtain a prepolymer;

[0078] 3. Then add 1,6-hexanediamine to the prepolymer and continue to stir and react at 95°C for 20 hours;

[0079] 4. Finally, the temperature was lowered to 60°C, and the material was discharged after stirring for 2 hours to obtain the polyurethane with diamine chain extension;

[0080] In the above steps 1 to 4, the mass ratio of toluene diisocyanate, polyethylene glycol, xylene, dibutyltin dilaurate, and 1,6-hexanediamine is 20:25:30:5:20;

[0081] 5. Weigh glycidyl methacrylate and xylene respectively, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0082] 6. Then raise the temperature to 190°C, add dodecyl mercaptan and dibenzoyl peroxide into a glass flask, and reflux the mixture under nitrogen protection for 5 hours;

[0083] 7. Finally, cool down to 60°C and discharge the material to obtain the acrylic resin modified pressure-sensitive adhesive;

[0084] In the above steps 5 to 7, the mass ratio of glycidyl methacrylate, xylene, dodecyl mercaptan and dibenzoyl peroxide is 48:48:2:2;

[0085] 8. Weigh xylene, diamine-extended polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0086] 9. Then, the temperature was raised to 160°C under nitrogen protection, and then diethyl cyanophosphate was added to the reactor, followed by stirring and reacting at this temperature for 5 hours;

[0087] 10. Finally, the temperature is reduced to 60°C, and the material is discharged after continuing to stir for 0.5h to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive;

[0088] In the above steps 8 to 10, the mass ratio of the xylene, the diamine-extended polyurethane, the acrylate resin-modified pressure-sensitive adhesive, and diethyl cyanophosphate is 35:28:32:5.

[0089] The structure of the polyurethane-pressure-sensitive adhesive composite structural adhesive prepared in Example 1 is as follows: Figure 4 shown.

[0090] Embodiment 2:

[0091] like Figure 5 As shown, a method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive comprises the following steps:

[0092] 1. Weigh 4,4'-diphenylmethane diisocyanate, polyethylene glycol and xylene respectively and add them into a glass flask;

[0093] 2. Then, the temperature was raised to 95°C under nitrogen protection, and then stannous octoate was added into the glass flask, followed by stirring and reacting at this temperature for 5 hours to obtain a prepolymer;

[0094] 3. Then add ethylenediamine to the prepolymer and continue to stir and react at 95°C for 20 hours;

[0095] 4. Finally, the temperature was lowered to 60°C, and the material was discharged after stirring for 2 hours to obtain the polyurethane with diamine chain extension;

[0096] In the above steps 1 to 4, the mass ratio of 4,4'-diphenylmethane diisocyanate, polyethylene glycol, xylene, stannous octoate and ethylenediamine is 18:22:37:3:20;

[0097] 5. Weigh 2-ethyl acrylate and xylene separately, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0098] 6. Then raise the temperature to 190°C, add p-cresol and azobisisobutyronitrile into a glass flask, and reflux the mixture under nitrogen protection for 5 hours;

[0099] 7. Finally, cool down to 60°C and discharge the material to obtain the acrylic resin modified pressure-sensitive adhesive;

[0100] In the above steps 5 to 7, the mass ratio of the 2-ethylacrylate glycidyl ester, xylene, p-cresol, and azobisisobutyronitrile is 47:47:3:3;

[0101] 8. Weigh xylene, diamine-extended polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0102] 9. Then, the temperature was raised to 160°C under nitrogen protection, and then diphenylphosphoryl chloride was added to the reaction kettle, followed by stirring and reacting at this temperature for 5 hours;

[0103] 10. Finally, the temperature is reduced to 60°C, and the material is discharged after continuing to stir for 0.5h to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive;

[0104] In the above steps 8 to 10, the mass ratio of the xylene, the diamine-extended polyurethane, the acrylate resin-modified pressure-sensitive adhesive, and diphenylphosphinoyl chloride is 36:27:33:4.

[0105] Embodiment 3:

[0106] like Figure 5 As shown, a method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive comprises the following steps:

[0107] 1. Weigh hexamethylene diisocyanate, polyethylene glycol and xylene respectively and add them into a glass flask;

[0108] 2. Then, the temperature was raised to 95°C under nitrogen protection, and bismuth isooctanoate was added into the glass flask, followed by stirring and reacting at this temperature for 5 hours to obtain a prepolymer;

[0109] 3. Then add p-phenylenediamine to the prepolymer and continue to stir and react at 95°C for 20 hours; the proportion of diamine chain extender is;

[0110] 4. Finally, the temperature was lowered to 60°C, and the material was discharged after stirring for 2 hours to obtain the polyurethane with diamine chain extension;

[0111] In the above steps 1 to 4, the mass ratio of hexamethylene diisocyanate, polyethylene glycol, xylene, bismuth isooctanoate, and p-phenylenediamine is 17:23:36:4:20;

[0112] 5. Weigh glycidyl acrylate and xylene respectively, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0113] 6. Then raise the temperature to 190°C, add dodecyl mercaptan and dibenzoyl peroxide into a glass flask, and reflux the mixture under nitrogen protection for 5 hours;

[0114] 7. Finally, cool down to 60°C and discharge the material to obtain the acrylic resin modified pressure-sensitive adhesive;

[0115] In the above steps 5 to 7, the mass ratio of glycidyl acrylate, xylene, dodecyl mercaptan and dibenzoyl peroxide is 46:46:4:4;

[0116] 8. Weigh xylene, diamine-extended polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0117] 9. Then, the temperature was raised to 160°C under nitrogen protection, and then n-butyl phosphoric anhydride was added to the reaction kettle, followed by stirring and reacting at this temperature for 5 hours;

[0118] 10. Finally, the temperature is reduced to 60°C, and the material is discharged after continuing to stir for 0.5h to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive;

[0119] In the above steps 8 to 10, the mass ratio of the xylene, the diamine-extended polyurethane, the acrylate resin-modified pressure-sensitive adhesive, and the n-butyl phosphoric anhydride is 37:26:33:4.

[0120] Embodiment 4:

[0121] like Figure 5 As shown, a method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive comprises the following steps:

[0122] 1. Weigh isophorone diisocyanate, polyethylene glycol and xylene respectively and add them into a glass flask;

[0123] 2. Then, the temperature was raised to 95°C under nitrogen protection, and then dioctyltin was added into the glass flask, followed by stirring and reacting at this temperature for 5 hours to obtain a prepolymer;

[0124] 3. Then add ethylenediamine to the prepolymer and continue to stir and react at 95°C for 20 hours;

[0125] 4. Finally, the temperature was lowered to 60°C, and the material was discharged after stirring for 2 hours to obtain the polyurethane with diamine chain extension;

[0126] In the above steps 1 to 4, the mass ratio of isophorone diisocyanate, polyethylene glycol, xylene, dioctyltin and ethylenediamine is 19:21:36:3:21;

[0127] 5. Weigh glycidyl methacrylate and xylene respectively, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0128] 6. Then raise the temperature to 190°C, add p-cresol and azobisisobutyronitrile into a glass flask, and reflux the mixture under nitrogen protection for 5 hours;

[0129] 7. Finally, cool down to 60°C and discharge the material to obtain the acrylic resin modified pressure-sensitive adhesive;

[0130] In the above steps 5 to 7, the mass ratio of glycidyl methacrylate, xylene, p-cresol, and azobisisobutyronitrile is 45:45:5:5;

[0131] 8. Weigh xylene, diamine-extended polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0132] 9. Then, the temperature was raised to 160°C under nitrogen protection, and then diethyl cyanophosphate was added to the reactor, followed by stirring and reacting at this temperature for 5 hours;

[0133] 10. Finally, the temperature is reduced to 60°C, and the material is discharged after continuing to stir for 0.5h to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive;

[0134] In the above steps 8 to 10, the mass ratio of the xylene, the diamine-extended polyurethane, the acrylate resin-modified pressure-sensitive adhesive, and diethyl cyanophosphate is 38:25:32:5.

[0135] Embodiment 5:

[0136] like Figure 5 As shown, a method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive comprises the following steps:

[0137] 1. Weigh toluene diisocyanate, polyethylene glycol and xylene respectively and add them into a glass flask;

[0138] 2. Then, the temperature was raised to 95°C under nitrogen protection, and then dibutyltin dilaurate was added to the glass flask, followed by stirring and reacting at this temperature for 5 hours to obtain a prepolymer;

[0139] 3. Then add 1,4-cyclohexanediamine to the prepolymer and continue to stir and react at 95°C for 20 hours;

[0140] 4. Finally, the temperature was lowered to 60°C, and the material was discharged after stirring for 2 hours to obtain the polyurethane with diamine chain extension;

[0141] In the above steps 1 to 4, the mass ratio of toluene diisocyanate, polyethylene glycol, xylene, dibutyltin dilaurate, and 1,4-cyclohexanediamine is 21:20:37:3:19;

[0142] 5. Weigh glycidyl acrylate and xylene respectively, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0143] 6. Then raise the temperature to 190°C, add dodecyl mercaptan and dibenzoyl peroxide into a glass flask, and reflux the mixture under nitrogen protection for 5 hours;

[0144] 7. Finally, cool down to 60°C and discharge the material to obtain the acrylic resin modified pressure-sensitive adhesive;

[0145] In the above steps 5 to 7, the mass ratio of glycidyl acrylate, xylene, dodecyl mercaptan and dibenzoyl peroxide is 46:46:4:4;

[0146] 8. Weigh xylene, diamine-extended polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0147] 9. Then, the temperature was raised to 160°C under nitrogen protection, and then diphenylphosphoryl chloride was added to the reaction kettle, followed by stirring and reacting at this temperature for 5 hours;

[0148] 10. Finally, the temperature is reduced to 60°C, and the material is discharged after continuing to stir for 0.5h to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive;

[0149] In the above steps 8 to 10, the mass ratio of the xylene, the diamine-extended polyurethane, the acrylate resin-modified pressure-sensitive adhesive, and diphenylphosphinoyl chloride is 35:29:31:5.

[0150] Embodiment 6:

[0151] like Figure 5 As shown, a method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive comprises the following steps:

[0152] 1. Weigh isophorone diisocyanate, polyethylene glycol and xylene respectively and add them into a glass flask;

[0153] 2. Then, the temperature was raised to 95° C. under nitrogen protection, and bismuth neodecanoate was added into the glass flask, followed by stirring and reacting at this temperature for 5 h to obtain a prepolymer;

[0154] 3. Then add p-phenylenediamine to the prepolymer and continue to stir and react at 95°C for 20 hours;

[0155] 4. Finally, the temperature was lowered to 60°C, and the material was discharged after stirring for 2 hours to obtain the polyurethane with diamine chain extension;

[0156] In the above steps 1 to 4, the mass ratio of isophorone diisocyanate, polyethylene glycol, xylene, bismuth neodecanoate, and p-phenylenediamine is 18:22:37:3:20;

[0157] 5. Weigh 2-ethyl acrylate and xylene separately, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0158] 6. Then raise the temperature to 190°C, add p-cresol and dibenzoyl peroxide into a glass flask, and reflux the mixture under nitrogen protection for 5 hours;

[0159] 7. Finally, cool down to 60°C and discharge the material to obtain the acrylic resin modified pressure-sensitive adhesive;

[0160] In the above steps 5 to 7, the mass ratio of the 2-ethylacrylate glycidyl ester, xylene, p-cresol, and dibenzoyl peroxide is 46:46:4:4;

[0161] 8. Weigh xylene, diamine-extended polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0162] 9. Then, the temperature was raised to 160°C under nitrogen protection, and then diethyl cyanophosphate was added to the reactor, followed by stirring and reacting at this temperature for 5 hours;

[0163] 10. Finally, the temperature is reduced to 60°C, and the material is discharged after continuing to stir for 0.5h to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive;

[0164] In the above steps 8 to 10, the mass ratio of the xylene, the diamine-extended polyurethane, the acrylate resin-modified pressure-sensitive adhesive, and diphenylphosphinoyl chloride is 36:27:33:4.

[0165] Comparative Example 1:

[0166] A method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive comprises the following steps:

[0167] 1. Weigh toluene diisocyanate, polyethylene glycol and xylene respectively and add them into a glass flask;

[0168] 2. Then, the temperature was raised to 95°C under nitrogen protection, and then dibutyltin dilaurate was added to the glass flask, followed by stirring and reacting at this temperature for 5 hours to obtain a prepolymer;

[0169] 3. Then add ethylene glycol to the prepolymer and continue to stir and react at 95°C for 20 hours;

[0170] 4. Finally, the temperature is reduced to 60°C, and the material is discharged after stirring for 2 hours to obtain polyurethane;

[0171] In the above steps 1 to 4, the mass ratio of toluene diisocyanate, polyethylene glycol, xylene, dibutyltin dilaurate, and ethylene glycol is 20:25:30:5:20;

[0172] 5. Weigh glycidyl methacrylate and xylene respectively, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0173] 6. Then raise the temperature to 190°C, add dodecyl mercaptan and dibenzoyl peroxide into a glass flask, and reflux the mixture under nitrogen protection for 5 hours;

[0174] 7. Finally, cool down to 60°C and discharge the material to obtain the acrylic resin modified pressure-sensitive adhesive;

[0175] In the above steps 5 to 7, the mass ratio of glycidyl methacrylate, xylene, dodecyl mercaptan and dibenzoyl peroxide is 48:48:2:2;

[0176] 8. Weigh xylene, polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0177] 9. Then, the temperature was raised to 160°C under nitrogen protection, and then diethyl cyanophosphate was added to the reactor, followed by stirring and reacting at this temperature for 5 hours;

[0178] 10. Finally, the temperature is reduced to 60°C, and the material is discharged after continuing to stir for 0.5h to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive;

[0179] In the above steps 8 to 10, the mass ratio of xylene, polyurethane, acrylate resin modified pressure-sensitive adhesive, and diethyl cyanophosphate is 35:28:32:5.

[0180] Comparative Example 2:

[0181] A method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive comprises the following steps:

[0182] 1. Weigh toluene diisocyanate, polyethylene glycol and xylene respectively and add them into a glass flask;

[0183] 2. Then, the temperature was raised to 95°C under nitrogen protection, and then dibutyltin dilaurate was added to the glass flask, followed by stirring and reacting at this temperature for 5 hours to obtain a prepolymer;

[0184] 3. Then add 1,6-hexanediamine to the prepolymer and continue to stir and react at 95°C for 20 hours;

[0185] 4. Finally, the temperature was lowered to 60°C, and the material was discharged after stirring for 2 hours to obtain the polyurethane with diamine chain extension;

[0186] In the above steps 1 to 4, the mass ratio of toluene diisocyanate, polyethylene glycol, xylene, dibutyltin dilaurate, and 1,6-hexanediamine is 20:25:30:5:20;

[0187] 5. Weigh ethyl methacrylate and xylene separately, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0188] 6. Then raise the temperature to 190°C, add dodecyl mercaptan and dibenzoyl peroxide into a glass flask, and reflux the mixture under nitrogen protection for 5 hours;

[0189] 7. Cool down to 60°C and discharge the material to obtain ethyl methacrylate modified pressure-sensitive adhesive;

[0190] In the above steps 5 to 7, the mass ratio of ethyl methacrylate, xylene, dodecyl mercaptan and dibenzoyl peroxide is 48:48:2:2;

[0191] 8. Weigh xylene, diamine-extended polyurethane and ethyl methacrylate modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0192] 9. Then, the temperature was raised to 160°C under nitrogen protection, and then diethyl cyanophosphate was added to the reactor, followed by stirring and reacting at this temperature for 5 hours;

[0193] 10. Finally, the temperature is reduced to 60°C, and the material is discharged after continuing to stir for 0.5h to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive;

[0194] In the above steps 8 to 10, the mass ratio of the xylene, the diamine-extended polyurethane, the ethyl methacrylate-modified pressure-sensitive adhesive, and the diethyl cyanophosphate is 35:28:32:5.

[0195] Comparative Example 3:

[0196] A method for preparing a polyurethane-pressure-sensitive adhesive composite structural adhesive comprises the following steps:

[0197] 1. Weigh toluene diisocyanate, polyethylene glycol and xylene respectively and add them into a glass flask;

[0198] 2. Then, the temperature was raised to 95°C under nitrogen protection, and then dibutyltin dilaurate was added to the glass flask, followed by stirring and reacting at this temperature for 5 hours to obtain a prepolymer;

[0199] 3. Then add ethylene glycol to the prepolymer and continue to stir and react at 95°C for 20 hours;

[0200] 4. Finally, the temperature is reduced to 60°C, and the material is discharged after stirring for 2 hours to obtain polyurethane;

[0201] In the above steps 1 to 4, the mass ratio of toluene diisocyanate, polyethylene glycol, xylene, dibutyltin dilaurate, and ethylene glycol is 20:25:30:5:20;

[0202] 5. Weigh ethyl methacrylate and xylene separately, add them into a glass flask, stir and slowly heat up under nitrogen protection;

[0203] 6. Then raise the temperature to 190°C, add dodecyl mercaptan and dibenzoyl peroxide into a glass flask, and reflux the mixture under nitrogen protection for 5 hours;

[0204] 7. Finally, cool down to 60°C and discharge the material to obtain ethyl methacrylate modified pressure-sensitive adhesive;

[0205] In the above steps 5 to 7, the mass ratio of ethyl methacrylate, xylene, dodecyl mercaptan and dibenzoyl peroxide is 48:48:2:2;

[0206] 8. Weigh xylene, polyurethane and ethyl methacrylate modified pressure-sensitive adhesive respectively, and add them into the reaction kettle;

[0207] 9. Then, the temperature was raised to 160°C under nitrogen protection, and then diethyl cyanophosphate was added to the reactor, followed by stirring and reacting at this temperature for 5 hours;

[0208] 10. Finally, the temperature is reduced to 60°C, and the material is discharged after continuing to stir for 0.5h to obtain a polyurethane-pressure-sensitive adhesive composite structural adhesive;

[0209] In the above steps 8 to 10, the mass ratio of xylene, polyurethane, ethyl methacrylate modified pressure-sensitive adhesive, and diethyl cyanophosphate is 35:28:32:5.

[0210] Referring to GBT 7124-2008, a tensile testing machine was used to test the tensile shear strength of the polyurethane-pressure sensitive adhesive composite structural adhesive, and the strength of the adhesion of the polyurethane-pressure sensitive adhesive composite structural adhesive was evaluated by the tensile shear strength.

[0211] Table 1 Performance test results of polyurethane-pressure-sensitive adhesive composite structural adhesives prepared in Examples and Comparative Examples

[0212] Tensile shear strength (MPa) Example 1 59 Example 2 63 Example 3 62 Example 4 68 Example 5 64 Example 6 65 Comparative Example 1 35 Comparative Example 2 37 Comparative Example 3 31

[0213] As can be seen from Table 1, the tensile shear strength of Examples 1 to 6 is higher than that of Comparative Examples 1 to 3. This is because the polyurethane-pressure-sensitive adhesive composite structural adhesive prepared in Examples 1 to 6 is obtained by a composite reaction of a polyurethane extended by diamine and a pressure-sensitive adhesive modified by an acrylate resin. The polyurethane extended by diamine contains a large number of -NH- groups, in which the nitrogen atom carries a lone pair of electrons and has a strong nucleophilicity; while the acrylate resin modified pressure-sensitive adhesive contains a large number of epoxy groups, in which the oxygen atom has a large electronegativity, so that the carbon atoms on the ring carry a partial positive charge, which makes it easy to be attacked by nucleophilic reagents. Therefore, the above two groups can react chemically under certain conditions, and the -NH- group acts as a nucleophilic reagent to attack the carbon atoms on the epoxy group, causing the epoxy group to open the ring, so that the polyurethane and the pressure-sensitive adhesive are compounded together through chemical bonds from a microscopic structure, achieving an effect higher than that of compounding by simple physical means. Moreover, the polyurethane-pressure-sensitive adhesive composite structural adhesive contains a large number of oxygen atoms and nitrogen atoms, so it can produce stronger cohesive force, and can form more hydrogen bonds with hydroxyl groups on the surface of the bonded material, greatly enhancing the bonding force.

[0214] In Comparative Examples 1 to 3, there is no reaction between the -NH- group and the epoxy group, so the polyurethane and the pressure-sensitive adhesive cannot be composited together in terms of microstructure, resulting in poor performance.

[0215] The above results show and describe the basic principles and main features of the present invention as well as the advantages of the present invention.

[0216] Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the equivalents of the appended claims.

Claims

1. A polyurethane-pressure-sensitive adhesive composite structural adhesive, characterized in that: The polyurethane-pressure-sensitive adhesive composite structural adhesive is obtained by compounding polyurethane and pressure-sensitive adhesive; the polyurethane includes polyurethane extended by diamine; and the pressure-sensitive adhesive includes acrylate resin modified pressure-sensitive adhesive.

2. The polyurethane-pressure-sensitive adhesive composite structural adhesive according to claim 1, characterized in that: The structure of the diamine-extended polyurethane comprises: Wherein: R and R' represent organic groups, including aliphatic or aromatic groups.

3. The polyurethane-pressure sensitive adhesive composite structural adhesive according to claim 1, characterized in that: The preparation method of the diamine-chain-extended polyurethane comprises: Weigh diisocyanate, polyethylene glycol and solvent separately and add them into a glass flask; Then, the temperature is raised to 90-100° C. under nitrogen protection, and then a catalyst is added to the glass flask, followed by stirring and reacting at this temperature for 4-6 hours to obtain a prepolymer; Then, the diamine chain extender is added to the prepolymer, and the reaction is continued at 90 to 100° C. with stirring for 18 to 22 hours; Finally, the temperature is lowered to 50-60°C, and the material is discharged after stirring for 2-3 hours to obtain a diamine-chain-extended polyurethane.

4. The polyurethane-pressure-sensitive adhesive composite structural adhesive according to claim 3, characterized in that: The general formula of the diisocyanate is: O=C=NRN=O=C; wherein: R represents an organic group, including an aliphatic or aromatic group; the solvent includes xylene; the catalyst includes one or more of an organic tin compound and an organic bismuth compound; the general formula of the diamine chain extender is: NH2-R'-NH2; wherein: R' represents an organic group, including an aliphatic or aromatic group; the mass ratio of the diisocyanate, polyethylene glycol, solvent, catalyst, and diamine chain extender is (15-25):(20-30):(30-40):(2-5):(20-30).

5. The polyurethane-pressure-sensitive adhesive composite structural adhesive according to claim 1, characterized in that: The structure of the acrylic resin modified pressure-sensitive adhesive comprises: Wherein: R" represents a substituent on the vinyl group, including any one of hydrogen, methyl and ethyl.

6. The polyurethane-pressure sensitive adhesive composite structural adhesive according to claim 1, characterized in that: The preparation method of the acrylic resin modified pressure-sensitive adhesive specifically comprises the following steps: Weigh the acrylate monomer and solvent separately, add them into a glass flask, stir and heat under nitrogen protection; Then the temperature is raised to 180-200°C, a chain transfer agent and an initiator are added to the glass flask, and the mixture is refluxed and kept warm for 4-6 hours under nitrogen protection; Finally, the temperature is lowered to 50-60°C and the material is discharged to obtain the acrylic resin modified pressure-sensitive adhesive.

7. The polyurethane-pressure sensitive adhesive composite structural adhesive according to claim 6, characterized in that: The general formula of the acrylate monomer is: Wherein: R" represents a substituent on the vinyl group, including any one of hydrogen, methyl and ethyl; the solvent includes xylene; the chain transfer agent includes one or more of thiol chain transfer agents and alkylphenol chain transfer agents; the initiator includes one or more of azo initiators and acyl peroxides; the mass ratio of the acrylate monomer, the solvent, the chain transfer agent and the initiator is (45-50): (45-50): (2-5): (2-5).

8. The polyurethane-pressure sensitive adhesive composite structural adhesive according to claim 1, characterized in that: The composite reaction of the polyurethane and the pressure-sensitive adhesive comprises:

9. The method for preparing a polyurethane-pressure sensitive adhesive composite structural adhesive according to any one of claims 1 to 8, characterized in that: The preparation method of the polyurethane-pressure sensitive adhesive composite structural adhesive comprises: Weigh the solvent, diamine-extended polyurethane and acrylate resin modified pressure-sensitive adhesive respectively, and add them into the reaction kettle; Then, the temperature is raised to 150-160°C under nitrogen protection, and then a condensation agent is added to the reaction kettle, followed by stirring and reacting at this temperature for 4-6 hours; Finally, the temperature was lowered to 50-60°C, stirring was continued for 0.5h, and then the material was discharged to obtain a polyurethane-pressure sensitive adhesive composite structural adhesive.

10. The method for preparing the polyurethane-pressure sensitive adhesive composite structural adhesive according to claim 9, characterized in that: The solvent includes xylene; the condensing agent includes an organic phosphorus condensing agent; the mass ratio of the solvent, diamine-extended polyurethane, acrylate resin modified pressure-sensitive adhesive, and condensing agent is (30-40): (25-30): (35-40): (2-5).

Images