Polyurethane movable glue with high load-bearing persistent viscosity and preparation method thereof

Abstract

The invention belongs to the technical field of polyurethane, and particularly relates to high-load-bearing persistent viscosity polyurethane movable glue and a preparation method thereof. The component A is prepared from the following raw materials in percentage by mass: 2-10% of polyether polyol (1: 1), 1-10% of polyether polyol (2: 1: 1), and the balance of a component B; the content of the polyether polyol 2 is 87.99 to 97.45 percent; 0.5-2% of an anti-aging agent; 0.01%-0.05% of a catalyst; the component B is prepared from the following raw materials in percentage by mass: 11.6 to 43.9 percent of polyether polyol 3; 10.5% to 28.5% of hydroxypropyl methacrylate; the content of the diisocyanate is 45.1%-61.2%; after the prepared polyurethane movable glue is placed for 7 days, the lasting adhesion time of the polyurethane movable glue exceeds 60 minutes under the lasting adhesion test condition that the load is 5kg at the angle of 90 degrees; meanwhile, in a 180-degree stripping force test, the measured stripping force value is greater than or equal to 1300gf.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane, and in particular relates to a high-load-bearing and viscous polyurethane removable adhesive and a preparation method thereof. Background Art

[0002] As an important polymer material, polyurethane elastomer exhibits unique physical and chemical properties due to the presence of a large number of carbamate groups (-NHCOO-) in its main molecular chain. This block copolymer polymer material is usually prepared through a complex polyaddition reaction of polyether or polyester polyols, isocyanates, chain extenders, crosslinkers, catalysts and a small amount of additives. Its properties are between rubber and plastic, with a wide range of hardness and excellent physical and chemical properties, such as good wear resistance, tear strength and elastic recovery ability.

[0003] Among the many applications of polyurethane elastomers, polyurethane removable adhesive has received widespread attention in recent years due to its characteristics of traceless removability, reusability, washability, and excellent colloid strength. For example, in carpet anti-slip stickers, it can effectively prevent carpets from sliding without causing damage to carpets and floors; car anti-slip mats can ensure that items in the car remain stable during driving and improve driving safety; suction cup adhesive plays an important role in various adsorption scenarios; bathroom wall stickers can conveniently fix toiletries and are easy to clean and replace. With the improvement of people's living standards and the continuous improvement of their requirements for quality of life, the application areas of polyurethane removable adhesives are constantly expanding.

[0004] As the application of polyurethane removable adhesive becomes more and more extensive, the market has also put forward higher requirements for its performance. Especially in terms of high-load-bearing adhesion, the traditional polyurethane removable adhesive preparation technology can no longer meet current needs. In practical applications, many scenarios require polyurethane removable adhesive to maintain adhesion for a long time under a certain weight. This requirement poses higher challenges to the formula design, preparation process and raw material selection of polyurethane removable adhesive.

[0005] Therefore, developing a polyurethane removable adhesive with excellent high load-bearing adhesion is of great significance for expanding the application field of polyurethane removable adhesive and meeting market demand. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a high-load-bearing polyurethane removable adhesive. After being placed for 7 days, the polyurethane removable adhesive has a stickiness time of more than 60 minutes under the stickiness test condition of a 90° angle and a load of 5 kg; at the same time, in the 180° peel force test, the measured peel force value is ≥1300gf.

[0007] Another object of the present invention is to provide a method for preparing a high load-bearing adhesive polyurethane removable glue.

[0008] The technical solution adopted by the present invention is as follows: The high load-bearing adhesive polyurethane removable glue is prepared from component A and component B in a mass ratio of 100:(17 - 42). Among them, component A is composed of raw materials in the following mass percentages: Polyether polyol 1: 2 - 10%; Polyether polyol 2: 87.99 - 97.45%; Anti-aging agent: 0.5 - 2%; Catalyst: 0.01 - 0.05%; Component B is composed of raw materials in the following mass percentages: Polyether polyol 3: 11.6 - 43.9%; Hydroxypropyl methacrylate: 10.5 - 28.5%; Diisocyanate: 45.1 - 61.2%; The number average molecular weight of the polyether polyol 1 is 300 - 500, and the functionality is 3 - 4; The number average molecular weight of the polyether polyol 2 is 4800 - 6000, and the functionality is 3; The molecular weight of the polyether polyol 3 is 1500 - 4000, and the functionality is 2.

[0009] The polyether polyol 1 is NJ-403 or MN-500, preferably NJ-403.

[0010] The polyether polyol 2 is EP-330N(G) or EP-3600, preferably EP-3600.

[0011] The polyether polyol 3 is DL-4000D or DL-3000D, preferably DL-4000D.

[0012] The anti-aging agent is one or more of ultraviolet absorber UV-531, ultraviolet absorber UV-2, ultraviolet absorber UV-1, antioxidant 1010 or antioxidant 1076.

[0013] The catalyst is an organic bismuth catalyst or an isooctanoate catalyst, preferably an organic bismuth catalyst. Among them, the isooctanoate catalyst includes lead isooctanoate or zinc isooctanoate.

[0014] The diisocyanate is MDI isocyanate, preferably one or more of MDI-100 or carbodiimide-modified MDI.

[0015] The preparation method of the high-load holding-viscosity polyurethane removable adhesive includes the following steps: (1) Preparation of component A: Mix polyether polyol 1 and polyether polyol 2, heat up to 95 - 110 °C, evacuate to below -0.095 MPa, dehydrate until the water content ≤ 0.05 wt.%, then cool down to 50 - 60 °C, add anti-aging agent and catalyst, and stir evenly to obtain component A; (2) Preparation of component B: Mix polyether polyol 3, hydroxypropyl methacrylate and diisocyanate, and react at 75 - 90 °C until the -NCO content is 10 - 11 wt.% to obtain component B; (3) Mix component A and component B evenly at 25 - 35 °C according to the mass ratio, quickly pour them into a mold at 80 - 100 °C, close the mold and cure for 3 - 5 min, then demold to obtain the high-load holding-viscosity polyurethane removable adhesive.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) For the high-load holding-viscosity polyurethane removable adhesive of the present invention, by introducing hydroxypropyl methacrylate into the molecular structure, the load-bearing holding viscosity of the colloid is significantly improved. The double bond structure in hydroxypropyl methacrylate can participate in the polymerization reaction in the polyurethane system, increasing the proportion of polar groups, enhancing the intermolecular interaction between polyurethane molecules and substrate molecules, and improving the adhesion. At the same time, the formed acrylic system branches increase the contact area between the system and the substrate, improve the wettability, and further enhance the adhesion, making the colloid not easy to fall off when bearing a large load; (2) Through the specific raw material formula and preparation process of the present invention, the high-load holding-viscosity polyurethane removable adhesive prepared has excellent mechanical properties, with an elongation at break greater than 600%. The high elongation at break endows the colloid with excellent flexibility and elasticity, enabling it to maintain good performance within a large deformation range, and adapting to the use scenarios of pasting substrates with different shapes and sizes and under dynamic stress; (3) The high-load holding-viscosity polyurethane removable adhesive prepared by the present invention has a relatively high initial adhesion strength. After the product is formed and placed for 7 days, the 180° peel strength ≥ 1300 gf; (4) The preparation method of the high-load holding-viscosity polyurethane removable adhesive of the present invention has a fast molding speed and a moderate pot life, which is convenient for industrial mass production. Specific embodiments

[0017] The following further illustrates the present invention with reference to embodiments, but it does not limit the implementation of the present invention.

[0018] Unless otherwise specified, the raw materials used in the examples and comparative examples are all conventional commercially available raw materials, and the process methods used in the examples and comparative examples are all conventional methods in the art unless otherwise specified.

[0019] The descriptions of some raw materials used in the examples and comparative examples are as follows: NJ-403, with a functionality of 4 and a number-average molecular weight of 300, was purchased from Jurong Ningwu New Materials Co., Ltd.; MN-500, with a functionality of 3 and a number-average molecular weight of 500, was purchased from Bluestar Dongda Chemical Co., Ltd.; EP-330N(G), with a functionality of 3 and a number-average molecular weight of 4800, was purchased from Bluestar Dongda Chemical Co., Ltd.; EP-3600, with a functionality of 3 and a number-average molecular weight of 6000, was purchased from Bluestar Dongda Chemical Co., Ltd.; DL-4000D, with a functionality of 2 and a number-average molecular weight of 4000, was purchased from Bluestar Dongda Chemical Co., Ltd.; DL-3000D, with a functionality of 2 and a number-average molecular weight of 1500, was purchased from Bluestar Dongda Chemical Co., Ltd.; DL-400, with a functionality of 2 and a number-average molecular weight of 200, was purchased from Bluestar Dongda Chemical Co., Ltd.; MDI-100, was purchased from Wanhua Chemical Group Co., Ltd.; CD-C, is carbodiimide-modified MDI, was purchased from Bayer Group, Germany; Hydroxypropyl methacrylate, with a number-average molecular weight of 144, was purchased from Shandong Yaojia Chemical Co., Ltd.; Antioxidant 1076, was purchased from BASF Group, Germany; Ultraviolet absorber UV-1, was purchased from Guangzhou Zhiyi Chemical Co., Ltd.; Organic bismuth catalyst BiCAT ® 8118, was purchased from Leading Chemical Company, USA.

[0020] Example 1 The high load-bearing tacky polyurethane repositionable adhesive described above is prepared from component A and component B in a mass ratio of 100:17. Among them, component A is composed of raw materials in the following mass percentages: NJ-403: 2%; EP-3600: 97.45%; Antioxidant 1076: 0.5%; BiCAT ® 8118: 0.05%; Component B is composed of raw materials in the following mass percentages: DL-4000D: 11.6%; Hydroxypropyl methacrylate: 27.2%; MDI-100: 27.5%; CD-C: 33.7%; The preparation method of the high load-bearing and sticky polyurethane removable adhesive includes the following steps: (1) Preparation of component A: Mix NJ-403 and EP-3600, heat up to 102.5 ± 7.5 °C, evacuate to -0.095 MPa, dehydrate until the water content is 0.05 wt.%, then cool down to 55 ± 5 °C, and add antioxidant 1076 and BiCAT ® 8118, stir evenly to obtain component A; (2) Preparation of component B: Mix DL-4000D, hydroxypropyl methacrylate, MDI-100 and CD-C, react at 80 ± 5 °C for 3 h, evacuate to -0.095 MPa after the reaction to remove bubbles, and obtain component B, with its -NCO content measured to be 11 wt.%; (3) Mix component A and component B evenly at 30 ± 5 °C according to the mass ratio, quickly pour them into a mold at 90 ± 10 °C, close the mold and cure for 3 min, then demold to obtain the high load-bearing and sticky polyurethane removable adhesive.

[0021] Example 2 The high load-bearing and sticky polyurethane removable adhesive is made from component A and component B in a mass ratio of 100:42. Among them, component A is composed of raw materials with the following mass percentages: NJ-403: 10%; EP-3600: 87.99%; Antioxidant 1076: 2%; BiCAT ® 8118: 0.01%; Component B is composed of raw materials with the following mass percentages: DL-4000D: 12.2%; Hydroxypropyl methacrylate: 28.5%; MDI-100: 26.7%; CD-C: 32.6%; The preparation method of the high load-bearing and sticky polyurethane removable adhesive includes the following steps: (1) Preparation of component A: Mix NJ-403 and EP-3600, heat up to 102.5 ± 7.5 °C, evacuate to -0.095 MPa, dehydrate until the water content is 0.05 wt.%, then cool down to 55 ± 5 °C, and add antioxidant 1076 and BiCAT ® 8118, stir evenly to obtain component A; (2)Preparation of Component B: After mixing DL-4000D, hydroxypropyl methacrylate, MDI-100 and CD-C, react at 80 ± 5 °C for 3 h. After the reaction is completed, evacuate to -0.095 MPa to remove bubbles, obtaining Component B, and its -NCO content is measured to be 10 wt.%; (3)Mix Component A and Component B evenly at 30 ± 5 °C according to the mass ratio, quickly pour them into a mold at 90 ± 10 °C, close the mold and cure for 3 min, then demold to obtain the high load-bearing and high tack polyurethane repositionable adhesive.

[0022] Example 3 The high load-bearing and high tack polyurethane repositionable adhesive is made from Component A and Component B in a mass ratio of 100:37. Among them, Component A is composed of raw materials with the following mass percentages: NJ-403: 10%; EP-3600: 87.99%; Antioxidant 1076: 2%; BiCAT ® 8118: 0.01%; Component B is composed of raw materials with the following mass percentages: DL-4000D: 41.8%; Hydroxypropyl methacrylate: 10.5%; MDI-100: 21.4%; CD-C: 26.3%; The preparation method of the high load-bearing and high tack polyurethane repositionable adhesive includes the following steps: (1)Preparation of Component A: Mix NJ-403 and EP-3600, heat up to 102.5 ± 7.5 °C, evacuate to -0.095 MPa, dehydrate until the water content is 0.05 wt.%, then cool down to 55 ± 5 °C, add antioxidant 1076 and BiCAT ® 8118, stir evenly to obtain Component A; (2)Preparation of Component B: After mixing DL-4000D, hydroxypropyl methacrylate, MDI-100 and CD-C, react at 80 ± 5 °C for 3 h. After the reaction is completed, evacuate to -0.095 MPa to remove bubbles, obtaining Component B, and its -NCO content is measured to be 11 wt.%; (3)Mix Component A and Component B evenly at 30 ± 5 °C according to the mass ratio, quickly pour them into a mold at 90 ± 10 °C, close the mold and cure for 3 min, then demold to obtain the high load-bearing and high tack polyurethane repositionable adhesive.

[0023] Example 4 The described high-load holding tacky polyurethane transfer adhesive is made from component A and component B in a mass ratio of 100:26. Among them, component A consists of raw materials in the following mass percentages: NJ-403: 5%; EP-3600: 93.97%; Antioxidant 1076: 1%; BiCAT ® 8118: 0.03%; Component B consists of raw materials in the following mass percentages: DL-4000D: 43.9%; Hydroxypropyl methacrylate: 11%; MDI-100: 20.3%; CD-C: 24.8%; The preparation method of the described high-load holding tacky polyurethane transfer adhesive includes the following steps: (1) Preparation of component A: Mix NJ-403 and EP-3600, heat up to 102.5 ± 7.5 °C, evacuate to -0.095 MPa, dehydrate until the water content is 0.05 wt.%, then cool down to 55 ± 5 °C, and add antioxidant 1076 and BiCAT ® 8118, stir evenly to obtain component A; (2) Preparation of component B: Mix DL-4000D, hydroxypropyl methacrylate, MDI-100 and CD-C, react at 80 ± 5 °C for 3 h, evacuate to -0.095 MPa after the reaction is completed to remove bubbles, obtain component B, and measure its -NCO content to be 10 wt.%; (3) Mix component A and component B evenly at 30 ± 5 °C according to the mass ratio, quickly pour them into a mold at 90 ± 10 °C, close the mold and cure for 5 min, then demold to obtain the high-load holding tacky polyurethane transfer adhesive.

[0024] Example 5 The described high-load holding tacky polyurethane transfer adhesive is made from component A and component B in a mass ratio of 100:24. Among them, component A consists of raw materials in the following mass percentages: MN-500: 5%; EP-330N(G): 94.47%; Ultraviolet absorber UV-1: 0.5%; BiCAT ® 8118: 0.03%; Component B consists of raw materials in the following mass percentages: DL-3000D: 43.9%; Hydroxypropyl methacrylate: 11%; MDI-100: 20.3%; CD-C: 24.8%; The preparation method of the high load-bearing and adhesive polyurethane removable adhesive includes the following steps: (1) Preparation of component A: Mix MN-500 and EP-330N(G), heat up to 102.5 ± 7.5 °C, evacuate to -0.095 MPa, dehydrate until the water content is 0.05 wt.%, then cool down to 55 ± 5 °C, and add ultraviolet absorber UV-1 and BiCAT ® 8118, stir evenly to obtain component A; (2) Preparation of component B: Mix DL-3000D, hydroxypropyl methacrylate, MDI-100 and CD-C, and react at 80 ± 5 °C for 3 h. After the reaction, evacuate to -0.095 MPa to remove bubbles to obtain component B, and measure its -NCO content to be 10 wt.%; (3) Mix component A and component B evenly at 30 ± 5 °C by mass ratio, quickly pour them into a mold at 90 ± 10 °C, close the mold and cure for 5 min, then demold to obtain the high load-bearing and adhesive polyurethane removable adhesive.

[0025] Comparative Example 1 The difference from Example 1 is that hydroxypropyl methacrylate in component B is replaced with DL-400 with the same mass percentage, and the -NCO content of the prepared component B is 11.2 wt.%, and the others are the same as Example 1.

[0026] Comparative Example 2 The difference from Example 2 is that hydroxypropyl methacrylate in component B is replaced with DL-400 with the same mass percentage, and the -NCO content of the prepared component B is 10.1 wt.%, and the others are the same as Example 2.

[0027] Comparative Example 3 The suction cup hook purchased from JD.com has a main body made of ABS, and the product number is 10145233401657.

[0028] Comparative Example 4 The acrylate pressure-sensitive adhesive, model is Henkel DUR0-TAK 129A from Germany, and the performance test is carried out after being prepared into a finished product according to the product operation manual.

[0029] The adhesive samples of Examples 1-5 and Comparative Examples 1-4 are placed for 7 days respectively and then the performance tests are carried out. The test methods are as follows: Elongation at break: Tested with reference to GB / T 528-2009; 180° peel strength: Tested in accordance with GB / T 15254-2014; 90° angle hanging time: After the polyurethane repositionable adhesives prepared in the examples and comparative examples were placed for 7 days respectively, polyurethane repositionable adhesive samples with a diameter of 6 cm and a thickness of 2 mm were cut. The bonding substrate was a smooth ceramic plate, and a non-adhesive suction cup hook with a diameter of 6 cm was bonded to the other side. Under the condition of a load of 5 kg, it was hung at a 90° angle, and the time until the adhesive layer separated was recorded, and whether there was residual glue on the ceramic plate after separation was observed; The test results are shown in Table 1: Table 1 Performance test results

[0030] From the data in Table 1, it can be seen that the 180° peel strength of the polyurethane repositionable adhesives prepared in Examples 1 to 5 is relatively high. This is because the introduction of acrylic branches increases the contact wettability between the system and the substrate, expands the contact area between the system and the substrate, and then improves the intermolecular force, so the bonding strength is enhanced. Among them, compared with Example 1, in Example 2, the A component contains a higher proportion of high-functional polyether polyol. Under the condition of the same reaction coefficient, the molding effect of the system is better, but the elongation rate is low, and the 180° peel strength is slightly lower than that of Example 1.

[0031] Comparing Example 1 and 2 with Example 3 and 4 respectively, it is found that as the addition amount of hydroxypropyl methacrylate in the system increases, the dropping time of the 90° angle hanging test is significantly improved, that is, the load-bearing holding viscosity effect is good. This is because the acrylic system contains double bonds, which increases the proportion of polar groups in the polyurethane, thereby enhancing the adhesion to the substrate.

[0032] Comparing Example 1 and 2 with Comparative Example 1 and 2 respectively, it is found that the 180° peel strength of the system with the introduction of hydroxypropyl methacrylate in the molecular structure is higher than that of the ordinary polyether polyol system, and the 90° angle hanging time is also greatly improved.

[0033] Comparative Example 3 is a commercially available suction cup hook. It can be seen from the test data that its 90° angle hanging time is much lower than that of the examples.

[0034] Comparative Example 4 is an acrylate pressure-sensitive adhesive. It can be seen from the data that its 180° peel strength is relatively high, and it does not fall off at a 90° angle, and the overall performance is good. However, obvious residual glue appears on the ceramic plate after the test is completed and separated, which is contrary to the performance requirement of the polyurethane repositionable adhesive prepared in the present invention that there is no residual glue on the substrate after separation. This is because the acrylic system contains a large number of double bonds, and the cohesive force and polarity are extremely strong. Excessive acrylic leads to too strong adhesion to the substrate and residual glue appears.

Claims

1. A high load-bearing and viscous polyurethane removable adhesive, characterized in that: It is made of component A and component B in a mass ratio of 100: (17-42), wherein component A is composed of the following raw materials in mass percentage: Polyether polyol 1: 2~10%; Polyether polyol 2: 87.99~97.45%; Anti-aging agent: 0.5~2%; Catalyst: 0.01~0.05%; Component B is composed of the following raw materials in percentage by mass: Polyether polyol 3: 11.6~43.9%; Hydroxypropyl methacrylate: 10.5~28.5%; Diisocyanate: 45.1~61.2%; The number average molecular weight of the polyether polyol 1 is 300-500, and the functionality is 3-4; The number average molecular weight of the polyether polyol 2 is 4800-6000 and the functionality is 3; The molecular weight of the polyether polyol 3 is 1500-4000 and the functionality is 2.

2. The high load-bearing and viscous polyurethane removable adhesive according to claim 1, characterized in that: The polyether polyol 1 is NJ-403 or MN-500.

3. The high load-bearing and viscous polyurethane removable adhesive according to claim 1, characterized in that: The polyether polyol 2 is EP-330N(G) or EP-3600.

4. The high load-bearing and viscous polyurethane removable adhesive according to claim 1, characterized in that: The polyether polyol 3 is DL-4000D or DL-3000D.

5. The high load-bearing and viscous polyurethane removable adhesive according to claim 1, characterized in that: The anti-aging agent is one or more of the ultraviolet absorber UV-531, the ultraviolet absorber UV-2, the ultraviolet absorber UV-1, the antioxidant 1010 or the antioxidant 1076.

6. The high load-bearing and viscous polyurethane removable adhesive according to claim 1, characterized in that: The catalyst is an organic bismuth catalyst or an isooctanoate catalyst.

7. The high load-bearing and viscous polyurethane removable adhesive according to claim 1, characterized in that: The diisocyanate is MDI isocyanate.

8. A method for preparing the high load-bearing and viscous polyurethane removable adhesive according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Preparation of component A: polyether polyol 1 and polyether polyol 2 are mixed, dehydrated to a moisture content of ≤0.05 wt.%, added with an anti-aging agent and a catalyst after cooling, and stirred evenly to obtain component A; (2) Preparation of component B: polyether polyol 3, hydroxypropyl methacrylate and diisocyanate are mixed and reacted until the -NCO content is 10-11 wt.%, to obtain component B; (3) Component A and component B are mixed evenly according to the mass ratio, injected into the mold, molded and matured, and then demolded to obtain a high-load-bearing and viscous polyurethane transfer adhesive.

9. The method for preparing the high load-bearing and viscous polyurethane removable adhesive according to claim 8, characterized in that: In the step (1), the temperature is lowered to 50-60°C; in the step (2), the reaction temperature is 75-90°C.

10. The method for preparing the high load-bearing and viscous polyurethane removable adhesive according to claim 8, characterized in that: In the step (3), the temperature of the mold is 80-100°C, and the mold closing and aging time is 3-5 minutes.

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