Anti-aging polyurethane adhesive based on polyurethane synthesis technology and preparation method thereof

Abstract

The invention discloses an anti-aging polyurethane adhesive based on a polyurethane synthesis technology and a preparation method, and relates to the related field of adhesives, a UPy reversible polymer is introduced into an anti-aging polyurethane adhesive system, a dynamic quadruple hydrogen bond network can be constructed in a molecular structure, and the anti-aging polyurethane adhesive is prepared. The adhesive has excellent self-repairing capability and environmental adaptability, the structure can rapidly dissociate, recombine and repair microscopic cracks when subjected to ultraviolet, thermal oxidation or mechanical damage, the aging process is effectively delayed, the service life of the material is prolonged, the reliability of the material is improved, meanwhile, the UPy structure enhances the intermolecular acting force, the bonding strength and toughness are remarkably improved, and the service life of the adhesive is prolonged. And the adhesive layer is prevented from brittle rupture and falling.

Description

Technical Field

[0001] The present invention relates to adhesive related fields, and in particular to an aging-resistant polyurethane adhesive based on polyurethane synthesis technology and a preparation method thereof. Background Art

[0002] Polyurethane adhesives are widely used in construction, electronics, automotive and other fields due to their excellent bonding strength, flexibility and environmental adaptability. However, traditional polyurethane adhesives are easily affected by external environments such as ultraviolet light, heat, oxygen and moisture during long-term use, resulting in molecular chain degradation and destruction of cross-linked structures, resulting in aging problems such as yellowing, embrittlement and peeling, which seriously limit their application in high-durability occasions. In order to improve the aging resistance of polyurethane adhesives, existing technologies usually use methods such as adding anti-ultraviolet agents, antioxidants, and light stabilizers to modify them. Although this can delay performance degradation to a certain extent, it is still difficult to fundamentally solve the structural damage during the aging process. In addition, once microcracks appear in the adhesive during use, conventional materials cannot heal themselves and need to be replaced as a whole, increasing maintenance costs. Summary of the Invention

[0003] Therefore, in order to solve the above-mentioned shortcomings, the present invention provides an aging-resistant polyurethane adhesive based on polyurethane synthesis technology and a preparation method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: an aging-resistant polyurethane adhesive based on polyurethane synthesis technology is prepared from the following raw materials, calculated by weight: 25-40 parts of polyether polyol PPG2000, 5-20 parts of fluorosilicone end-modified polyether, 18-25 parts of HDI / IPDI isocyanate mixture, 0.5-3 parts of UPy reversible polymer, 0.5-3 parts of nano-SiO2, 1-2.5 parts of UV absorber, 0.5-1.5 parts of light stabilizer, 0.5-1.5 parts of antioxidant, 0.1-0.5 parts of DBTDL catalyst, 0.5-1.5 parts of CAB dispersant, and 10-20 parts of diluent.

[0005] Furthermore, the preparation method of the UPy reversible polymer is as follows: (1) Pre-drying the polyether glycol raw material at 80°C under reduced pressure for 2-3 hours; (2) Prepolymerization of polyether and HDI to generate -NCO-terminated prepolymer at a temperature of 70-80°C and a reaction time of 1.5-3h; (3) Add UPy-NH2 end groups dropwise to cap the prepolymer, the temperature is 55-65°C, and the reaction is continued for 2-3 hours; (4) Control the complete reaction of NCO, monitor the temperature, and confirm that there is no residual NCO peak; (5) Remove the solvent and dry under reduced pressure, vacuum degree -0.08 MPa, dry at 40-50 °C for 6 hours; (6) A UPy-terminated polyurethane main chain reversible polymer was obtained as a light yellow transparent viscous substance.

[0006] Furthermore, the present invention provides a method for preparing an aging-resistant polyurethane adhesive based on polyurethane synthesis technology, comprising the following steps: S1 polyether polyol PPG2000 and fluorosilicone end-group modified polyether are added to the reactor in proportion, heated and stirred to mix at 60-70°C and 200-400 rpm. S2 dehydration treatment, remove moisture, vacuum degree: <-0.08 MPa; 70-80℃, 30-60 min; S3: Add HDI / IPDI isocyanate mixture dropwise to continue the reaction to form NCO-terminated prepolymer at a rate of 1 mL / min and a temperature of 80-85°C for 1.5-2.5 h. S4 cools down to 50-55℃, adds UV absorber, HALS light stabilizer and antioxidant and stirs evenly. S5: Add surface treated nano-SiO2 and CAB dispersant, continue stirring until uniform, stirring speed: 400-600 rpm, 20-30 min; S6 adds UPy reversible polymer, temperature control: ≤50℃; S7 added DBTDL catalyst and stirred gently for 10 min; S8 Add diluent to adjust the viscosity to 800-3000 cps; S9 sieve filter, 120-150 mesh, temperature controlled at 30-40℃; S10 filling and sealing, stored in dry nitrogen, humidity <40%; storage temperature: 5-30℃.

[0007] Preferably, the HDI / IPDI isocyanate mixture is typically 2:1.

[0008] Preferably, the nano-SiO2 is surface-treated with silane.

[0009] Preferably, the antioxidant is 1010 plus 168, with a ratio of 1:1.

[0010] Beneficial effects of the present invention: By introducing UPy reversible polymer into the aging-resistant polyurethane adhesive system, the present invention can construct a dynamic quadruple hydrogen bond network in the molecular structure, giving the adhesive excellent self-repair ability and environmental adaptability. This structure can quickly dissociate and reorganize when subjected to ultraviolet, thermal oxygen or mechanical damage, repairing microcracks, effectively delaying the aging process, and improving the service life and reliability of the material. At the same time, the UPy structure enhances the intermolecular force, significantly improving the bonding strength and toughness, and preventing the adhesive layer from cracking and falling off. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 is a comparative schematic diagram of three groups of embodiments of the present invention. DETAILED DESCRIPTION

[0012] In order to further explain the technical solution of the present invention, specific embodiments are described in detail below.

[0013] Example 1 The present invention provides an aging-resistant polyurethane adhesive based on polyurethane synthesis technology, which is prepared from the following raw materials, in parts by weight: 30 parts of polyether polyol PPG2000, 10 parts of fluorosilicone end-group modified polyether, 20 parts of HDI / IPDI isocyanate mixture, 1 part of UPy reversible polymer, 1 part of nano-SiO2, 1.5 parts of UV absorber, 1 part of light stabilizer, 1 part of antioxidant, 0.3 part of DBTDL catalyst, 1 part of CAB dispersant, and 15 parts of diluent; The functions are described as follows: Polyether polyol PPG2000, the main flexible chain segment, determines elasticity and toughness; Fluorosilicone end-group modified polyether improves weather resistance, hydrophobicity and chemical stability; HDI / IPDI isocyanate mixture, typically 2:1, provides -NCO groups to react with polyols to form the backbone; UPy reversible polymer, self-healing, dynamic bond reorganization; Nano-SiO2, hollow silica, treated with silane on the surface to improve UV resistance and aging resistance and enhance the structure; UV absorber, using UV-328, absorbs ultraviolet rays to prevent degradation of the polyurethane main chain; Light stabilizer, using HALS-770, inhibits UV-induced photooxidative chain breakage; Antioxidant, which is antioxidant 1010 + 168, in a ratio of 1:1, to inhibit thermal oxidative aging; DBTDL (dibutyltin dilaurate) catalyst, catalyzes the reaction of NCO and OH; CAB (cellulose acetate butyrate) dispersant to disperse nanoparticles; Diluent, ethyl acetate, adjusts viscosity for ease of construction.

[0014] The preparation method of UPy reversible polymer is as follows: (1) Pre-dry the polyether diol raw material at 80°C under reduced pressure for 2.5 hours; (2) Pre-polymerize the polyether with HDI to generate a -NCO-terminated prepolymer at 75°C for 2.2 hours; (3) Add UPy-NH2 end groups dropwise to cap the prepolymer at 60°C for 2.5 hours; (4) Control the complete reaction of NCO, monitor the temperature and confirm that there is no residual NCO peak; (5) Remove the solvent, dry under reduced pressure, vacuum degree -0.08 MPa, and dry at 45°C for 6 hours; (6) Obtain a UPy-terminated polyurethane main chain reversible polymer as a light yellow transparent viscous solid.

[0015] The preparation method of the aging-resistant polyurethane adhesive based on polyurethane synthesis technology comprises the following steps: S1 polyether polyol PPG2000 and fluorosilicone end-group modified polyether were added to the reactor in proportion, heated and stirred to mix at 65°C and 300 rpm. S2 dehydration treatment, remove moisture, vacuum degree: <-0.08 MPa; 75℃, 45 min; S3: Add HDI / IPDI isocyanate mixture dropwise to continue the reaction to form NCO-terminated prepolymer at a rate of 1 mL / min and a temperature of 82°C for 2 h. S4 cools down to 52℃, adds UV absorber, HALS light stabilizer and antioxidant and stirs evenly. S5 Add surface treated nano-SiO2 and CAB dispersant, continue stirring until uniform, stirring speed: 500 rpm, 25 min; S6 adds UPy reversible polymer, temperature control: ≤50℃; S7 added DBTDL catalyst and stirred gently for 10 min; S8 adds diluent to adjust the viscosity to 1200cps; S9 was sieved and filtered, 135 mesh, and the temperature was controlled at 35℃; S10 filling and sealing, stored in dry nitrogen, humidity <40%; storage temperature: 5-30℃.

[0016] Example 2 An aging-resistant polyurethane adhesive based on polyurethane synthesis technology is prepared from the following raw materials, calculated by weight: 28 parts of polyether polyol PPG2000, 12 parts of fluorosilicone-terminated modified polyether, 22 parts of HDI / IPDI isocyanate mixture, 1 part of UPy reversible polymer, 2 parts of nano-SiO2, 2.5 parts of UV absorber, 1.5 parts of light stabilizer, 1.5 parts of antioxidant, 0.4 part of DBTDL catalyst, 1 part of CAB dispersant, and 16 parts of diluent.

[0017] The preparation method of the UPy reversible polymer and the preparation method of the aging-resistant polyurethane adhesive are the same as those in Example 1. When the temperature is 25° C., the viscosity is controlled at 1400 cps.

[0018] Example 3 An aging-resistant polyurethane adhesive based on polyurethane synthesis technology is prepared from the following raw materials, calculated by weight: 28 parts of polyether polyol PPG2000, 10 parts of fluorosilicone-terminated modified polyether, 22 parts of HDI / IPDI isocyanate mixture, 3 parts of UPy reversible polymer, 1 part of nano-SiO2, 1.5 parts of UV absorber, 1 part of light stabilizer, 1 part of antioxidant, 0.3 part of DBTDL catalyst, 1 part of CAB dispersant, and 15 parts of diluent.

[0019] The preparation method of the UPy reversible polymer and the preparation method of the aging-resistant polyurethane adhesive are the same as those in Example 1. When the temperature is 25° C., the viscosity is controlled at 1250 cps.

[0020] The following table compares the examples:

[0021] A performance comparison of the three groups of examples shows that Example 2 achieves the highest UV aging strength retention and peel strength on the basis of increasing the content of ultraviolet absorber, light stabilizer and antioxidant, reflecting excellent aging resistance; and although Example 3 maintains a moderate ratio in terms of anti-aging additives, by increasing the content of UPy structured polyether and introducing a dynamic reversible hydrogen bond network, it has outstanding performance in elongation at break and self-repair performance, and has strong structural recovery ability and ductility, making it suitable for application scenarios with higher requirements for flexibility and self-healing properties; in comparison, Example 1 is a baseline formula, and all performances are relatively medium, without reflecting any strengthening advantages, verifying the significant effect of the UPy reversible structure in improving the functionality of the adhesive.

[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An aging-resistant polyurethane adhesive based on polyurethane synthesis technology, characterized by: The invention is prepared from the following raw materials in parts by weight: 25-40 parts of polyether polyol PPG2000, 5-20 parts of fluorosilicone end-group modified polyether, 18-25 parts of HDI / IPDI isocyanate mixture, 0.5-3 parts of UPy reversible polymer, 0.5-3 parts of nano-SiO2, 1-2.5 parts of UV absorber, 0.5-1.5 parts of light stabilizer, 0.5-1.5 parts of antioxidant, 0.1-0.5 parts of DBTDL catalyst, 0.5-1.5 parts of CAB dispersant, and 10-20 parts of diluent; The preparation method of the UPy reversible polymer is as follows: (1) Pre-drying the polyether glycol raw material at 80°C under reduced pressure for 2-3 hours; (2) Prepolymerization of polyether and HDI to generate -NCO-terminated prepolymer at a temperature of 70-80°C and a reaction time of 1.5-3h; (3) Add UPy-NH2 end groups dropwise to cap the prepolymer, the temperature is 55-65°C, and the reaction is continued for 2-3 hours; (4) Control the complete reaction of NCO, monitor the temperature, and confirm that there is no residual NCO peak; (5) Remove the solvent and dry under reduced pressure, vacuum degree -0.08 MPa, dry at 40-50 °C for 6 hours; (6) A UPy-terminated polyurethane main chain reversible polymer was obtained as a light yellow transparent viscous substance.

2. A method for preparing an aging-resistant polyurethane adhesive based on polyurethane synthesis technology according to claim 1, characterized in that: The following steps are involved: S1 polyether polyol PPG2000 and fluorosilicone end-group modified polyether are added to the reactor in proportion, heated and stirred to mix at 60-70°C and 200-400 rpm. S2 dehydration treatment, remove moisture, vacuum degree: <-0.08 MPa; 70-80℃, 30-60 min; S3: Add HDI / IPDI isocyanate mixture dropwise to continue the reaction to form NCO-terminated prepolymer at a dropwise rate of 1 mL / min. Temperature: 80-85°C, 1.5-2.5 hours; S4 cools down to 50-55℃, adds UV absorber, HALS light stabilizer and antioxidant and stirs evenly. S5: Add surface treated nano-SiO2 and CAB dispersant, continue stirring until uniform, stirring speed: 400-600 rpm, 20-30 min; S6 adds UPy reversible polymer, temperature control: ≤50℃; S7 added DBTDL catalyst and stirred gently for 10 min; S8 Add diluent to adjust the viscosity to 800-3000 cps; S9 sieve filter, 120-150 mesh, temperature controlled at 30-40℃; S10 filling and sealing, stored in dry nitrogen, humidity <40%; storage temperature: 5-30℃.

3. The method for preparing an aging-resistant polyurethane adhesive based on polyurethane synthesis technology according to claim 2, characterized in that: The HDI / IPDI isocyanate mixture is typically 2:

1.

4. The method for preparing an aging-resistant polyurethane adhesive based on polyurethane synthesis technology according to claim 2, characterized in that: The nano-SiO2 is surface-treated with silane.

5. The method for preparing an aging-resistant polyurethane adhesive based on polyurethane synthesis technology according to claim 2, characterized in that: The antioxidants are 1010 and 168, with a ratio of 1:1.

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