High-load holding-tack polyurethane removable adhesive and its preparation method

Abstract

The present invention belongs to the technical field of polyurethanes, and particularly relates to a high-load holding-tack polyurethane removable adhesive and a preparation method thereof. It is made up of component A and component B. 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%. After being placed for 7 days, the holding time of the obtained polyurethane removable adhesive exceeds 60 min under the holding-tack test conditions of a 90° angle load of 5 kg. At the same time, in the 180° peel strength test, the measured peel strength value ≥ 1300 gf.

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 preparation method of a high load-bearing and adhesive polyurethane removable adhesive.

[0008] The technical solution adopted by the present invention is as follows:

[0009] The high load-bearing and adhesive polyurethane removable adhesive 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:

[0010] Polyether polyol 1: 2 - 10%;

[0011] Polyether polyol 2: 87.99 - 97.45%;

[0012] Anti-aging agent: 0.5 - 2%;

[0013] Catalyst: 0.01 - 0.05%;

[0014] Component B is composed of raw materials in the following mass percentages:

[0015] Polyether polyol 3: 11.6 - 43.9%;

[0016] Hydroxypropyl methacrylate: 10.5 - 28.5%;

[0017] Diisocyanate: 45.1 - 61.2%;

[0018] The number average molecular weight of the polyether polyol 1 is 300 - 500, and the functionality is 3 - 4;

[0019] The number average molecular weight of the polyether polyol 2 is 4800 - 6000, and the functionality is 3;

[0020] The molecular weight of the polyether polyol 3 is 1500 - 4000, and the functionality is 2.

[0021] The polyether polyol 1 is NJ - 403 or MN - 500, preferably NJ - 403.

[0022] The polyether polyol 2 is EP - 330N(G) or EP - 3600, preferably EP - 3600.

[0023] The polyether polyol 3 is DL - 4000D or DL - 3000D, preferably DL - 4000D.

[0024] 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.

[0025] The catalyst is an organic bismuth catalyst or an isooctanoate catalyst, preferably an organic bismuth catalyst, wherein the isooctanoate catalyst includes lead isooctanoate or zinc isooctanoate.

[0026] The diisocyanate is MDI isocyanate, preferably one or more of MDI-100 or carbodiimide-modified MDI.

[0027] The method for preparing the high-load-bearing and viscous polyurethane removable adhesive comprises the following steps:

[0028] (1) Preparation of component A: polyether polyol 1 and polyether polyol 2 are mixed, heated to 95-110°C, vacuumed to below -0.095 MPa, dehydrated to a moisture content of ≤0.05 wt.%, then cooled to 50-60°C, an anti-aging agent and a catalyst are added, and stirred evenly to obtain component A;

[0029] (2) Preparation of component B: polyether polyol 3, hydroxypropyl methacrylate and diisocyanate are mixed and reacted at 75-90° C. until the -NCO content is 10-11 wt.%, thereby obtaining component B;

[0030] (3) Component A and component B are mixed evenly according to the mass ratio at 25-35°C, and quickly poured into a mold at a temperature of 80-100°C. After the mold is closed and matured for 3-5 minutes, the mold is demolded to obtain a high-load-bearing and viscous polyurethane transfer adhesive.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The high load-bearing and viscous polyurethane removable adhesive of the present invention significantly improves the load-bearing and viscous properties of the colloid by introducing hydroxypropyl methacrylate into the molecular structure. The double bond structure in hydroxypropyl methacrylate can participate in the polymerization reaction in the polyurethane system, increase the proportion of polar groups, enhance the interaction between the polyurethane molecules and the substrate molecules, and enhance the adhesion. At the same time, the acrylic acid system side chains formed increase the contact area between the system and the substrate, improve the wettability, and further enhance the adhesion, making the colloid less likely to fall off when subjected to a large load;

[0033] (2) The high-load-bearing and viscous polyurethane removable adhesive prepared by the present invention has excellent mechanical properties and an elongation of more than 600%, and the high elongation gives the colloid excellent flexibility and elasticity, so that it can maintain good performance within a large deformation range, and is suitable for the use of substrates of different shapes and sizes and under dynamic stress.

[0034] (3) The high load-bearing and viscous polyurethane removable adhesive prepared by the present invention has a high initial bonding strength. After the product is placed for 7 days after molding, the 180° peeling force is ≥1300gf;

[0035] (4) The preparation method of the high-load holding tack polyurethane removable adhesive of the present invention has a fast molding speed, a moderate operable time, and is convenient for industrial mass production. Detailed implementation manners

[0036] The present invention will be further described below in conjunction with embodiments, but it does not limit the implementation of the present invention.

[0037] 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.

[0038] Some of the raw materials used in the examples and comparative examples are described as follows:

[0039] NJ-403, with a functionality of 4 and a number average molecular weight of 300, purchased from Jurong Ningwu New Materials Co., Ltd.;

[0040] MN-500, with a functionality of 3 and a number average molecular weight of 500, purchased from Bluestar Dongda Chemical Co., Ltd.;

[0041] EP-330N(G), with a functionality of 3 and a number average molecular weight of 4800, purchased from Bluestar Dongda Chemical Co., Ltd.;

[0042] EP-3600, with a functionality of 3 and a number average molecular weight of 6000, purchased from Bluestar Dongda Chemical Co., Ltd.;

[0043] DL-4000D, with a functionality of 2 and a number average molecular weight of 4000, purchased from Bluestar Dongda Chemical Co., Ltd.;

[0044] DL-3000D, with a functionality of 2 and a number average molecular weight of 1500, purchased from Bluestar Dongda Chemical Co., Ltd.;

[0045] DL-400, with a functionality of 2 and a number average molecular weight of 200, purchased from Bluestar Dongda Chemical Co., Ltd.;

[0046] MDI-100, purchased from Wanhua Chemical Group Co., Ltd.;

[0047] CD-C, a carbodiimide-modified MDI, purchased from Bayer Group, Germany;

[0048] Hydroxypropyl methacrylate, with a number average molecular weight of 144, purchased from Shandong Yaojia Chemical Co., Ltd.;

[0049] Antioxidant 1076, purchased from BASF Group, Germany;

[0050] Ultraviolet absorber UV-1, purchased from Guangzhou Zhiyi Chemical Co., Ltd.;

[0051] Organic bismuth catalyst BiCAT ® 8118, purchased from a leading chemical company in the United States.

[0052] Example 1

[0053] The high-load holding-tack polyurethane removable adhesive described above is made from component A and component B in a mass ratio of 100:17. Among them, component A consists of raw materials in the following mass percentages:

[0054] NJ-403: 2%;

[0055] EP-3600: 97.45%;

[0056] Antioxidant 1076: 0.5%;

[0057] BiCAT ® 8118: 0.05%;

[0058] Component B consists of raw materials in the following mass percentages:

[0059] DL-4000D: 11.6%;

[0060] Hydroxypropyl methacrylate: 27.2%;

[0061] MDI-100: 27.5%;

[0062] CD-C: 33.7%;

[0063] The preparation method of the high-load holding-tack polyurethane removable adhesive described above includes the following steps:

[0064] (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;

[0065] (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 to remove bubbles after the reaction is completed to obtain component B, and measure its -NCO content to be 11 wt.%;

[0066] (3) Mix component A and component B evenly at 30 ± 5 °C according to the mass ratio, quickly pour it into a mold at 90 ± 10 °C, close the mold and cure for 3 min, then demold to obtain the high-load holding-tack polyurethane removable adhesive.

[0067] Example 2

[0068] The high-load holding-tack polyurethane repositionable adhesive described above is made from component A and component B in a mass ratio of 100:42. Among them, component A consists of raw materials in the following mass percentages:

[0069] NJ-403: 10%;

[0070] EP-3600: 87.99%;

[0071] Antioxidant 1076: 2%;

[0072] BiCAT ® 8118: 0.01%;

[0073] Component B consists of raw materials in the following mass percentages:

[0074] DL-4000D: 12.2%;

[0075] Hydroxypropyl methacrylate: 28.5%;

[0076] MDI-100: 26.7%;

[0077] CD-C: 32.6%;

[0078] The preparation method of the high-load holding-tack polyurethane repositionable adhesive described above includes the following steps:

[0079] (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;

[0080] (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 to remove bubbles after the reaction is completed, and obtain component B, and measure its -NCO content to be 10 wt.%;

[0081] (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 holding-tack polyurethane repositionable adhesive.

[0082] Example 3

[0083] The described high-load holding-tack polyurethane removable adhesive is made from component A and component B in a mass ratio of 100:37. Among them, component A consists of raw materials in the following mass percentages:

[0084] NJ-403: 10%;

[0085] EP-3600: 87.99%;

[0086] Antioxidant 1076: 2%;

[0087] BiCAT ® 8118: 0.01%;

[0088] Component B consists of raw materials in the following mass percentages:

[0089] DL-4000D: 41.8%;

[0090] Hydroxypropyl methacrylate: 10.5%;

[0091] MDI-100: 21.4%;

[0092] CD-C: 26.3%;

[0093] The preparation method of the described high-load holding-tack polyurethane removable adhesive includes the following steps:

[0094] (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;

[0095] (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 to remove bubbles after the reaction is completed, obtain component B, and measure its -NCO content to be 11 wt.%;

[0096] (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 holding-tack polyurethane removable adhesive.

[0097] Example 4

[0098] The described high-load holding-tack polyurethane removable 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:

[0099] NJ-403: 5%;

[0100] EP-3600: 93.97%;

[0101] Antioxidant 1076: 1%;

[0102] BiCAT ® 8118: 0.03%;

[0103] Component B is composed of raw materials in the following mass percentages:

[0104] DL-4000D: 43.9%;

[0105] Hydroxypropyl methacrylate: 11%;

[0106] MDI-100: 20.3%;

[0107] CD-C: 24.8%;

[0108] The preparation method of the high-load holding viscosity polyurethane removable adhesive includes the following steps:

[0109] (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;

[0110] (2) Preparation of Component B: Mix 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 to obtain Component B, and measure its -NCO content to be 10 wt.%;

[0111] (3) Mix Component A and Component B evenly at 30 ± 5 °C according to the mass ratio, quickly pour it into a mold at 90 ± 10 °C, close the mold and cure for 5 min, then demold to obtain the high-load holding viscosity polyurethane removable adhesive.

[0112] Example 5

[0113] The high-load holding viscosity polyurethane removable adhesive is made of Component A and Component B in a mass ratio of 100:24. Among them, Component A is composed of raw materials in the following mass percentages:

[0114] MN-500: 5%;

[0115] EP-330N(G): 94.47%;

[0116] Ultraviolet absorber UV-1: 0.5%;

[0117] BiCAT ® 8118: 0.03%;

[0118] Component B is composed of raw materials with the following mass percentages:

[0119] DL-3000D: 43.9%;

[0120] Hydroxypropyl methacrylate: 11%;

[0121] MDI-100: 20.3%;

[0122] CD-C: 24.8%;

[0123] The preparation method of the high-load holding viscosity polyurethane repositionable adhesive includes the following steps:

[0124] (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;

[0125] (2) Preparation of Component B: Mix DL-3000D, hydroxypropyl methacrylate, MDI-100 and CD-C, react at 80 ± 5 °C for 3 h, evacuate to -0.095 MPa to remove bubbles after the reaction is completed, obtain Component B, and measure its -NCO content to be 10 wt.%;

[0126] (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 viscosity polyurethane repositionable adhesive.

[0127] Comparative Example 1

[0128] The difference from Example 1 is that hydroxypropyl methacrylate in Component B is replaced with DL-400 with the same mass percentage, the -NCO content of the prepared Component B is 11.2 wt.%, and the others are the same as in Example 1.

[0129] Comparative Example 2

[0130] The difference from Example 2 is that hydroxypropyl methacrylate in Component B is replaced with DL-400 with the same mass percentage, the -NCO content of the prepared Component B is 10.1 wt.%, and the others are the same as in Example 2.

[0131] Comparative Example 3

[0132] The suction cup hook purchased from JD.com Mall has a main body made of ABS, and the product number is 10145233401657.

[0133] Comparative Example 4

[0134] The acrylate pressure-sensitive adhesive, with the model of Henkel DUR0-TAK 129A from Germany, was prepared into a finished product according to the product operation manual and then subjected to performance testing.

[0135] The adhesive samples of Examples 1 to 5 and Comparative Examples 1 to 4 were placed for 7 days respectively and then subjected to performance testing. The testing methods are as follows:

[0136] Elongation at break: Tested with reference to GB / T 528-2009;

[0137] 180° peel strength: Tested with reference to GB / T 15254-2014;

[0138] 90° angle suspension 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 suspended at a 90° angle, and the time until the adhesive layer separated was recorded, and whether there was residual adhesive on the ceramic plate after separation was observed;

[0139] The test results are shown in Table 1:

[0140] Table 1 Performance test results

[0141]

[0142] It can be seen from the data in Table 1 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 increases the intermolecular force, so the bonding strength is improved.

[0143] 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 system has a better molding effect, but the elongation at break is relatively low, and the 180° peel strength is slightly lower than that of Example 1.

[0144] 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 suspension test is significantly improved, that is, the load-bearing holding adhesion effect is good. This is because the acrylic system contains double bonds, which increases the proportion of polar groups in the polyurethane, thus enhancing the adhesion to the substrate.

[0145] 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 significantly improved.

[0146] 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.

[0147] Comparative Example 4 is an acrylate pressure-sensitive adhesive. It can be seen from the data that its 180° peel strength is high, 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 separation after the test, which is contrary to the performance requirement of the polyurethane removable adhesive prepared by the present invention that there is no residual glue on the substrate after separation. This is because the acrylic acid system contains a large number of double bonds, and the cohesive force and polarity are extremely strong. Excessive acrylic acid leads to too strong adhesion to the substrate and residual glue appears.

Claims

1. A high-load holding-tack polyurethane removable adhesive, characterized in that, It is made from component A and component B in a mass ratio of 100:(17 - 42). Among them, component A is composed of raw materials with 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 with 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 said polyether polyol 1 is 300 - 500, and the functionality is 3 - 4; The number-average molecular weight of the said polyether polyol 2 is 4800 - 6000, and the functionality is 3; The molecular weight of the said polyether polyol 3 is 1500 - 4000, and the functionality is 2.

2. The high-load holding-tack polyurethane repositionable adhesive according to claim 1, wherein The said polyether polyol 1 is NJ-403 or MN-500.

3. The high-load holding-tack polyurethane removable adhesive according to claim 1, wherein The said polyether polyol 2 is EP-330N(G) or EP-3600.

4. The high-load holding-tack polyurethane repositionable adhesive according to claim 1, wherein The said polyether polyol 3 is DL-4000D or DL-3000D.

5. The high-load holding-tack polyurethane repositionable adhesive according to claim 1, wherein, The said 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.

6. The high-load holding-tack polyurethane repositionable adhesive according to claim 1, wherein, The said catalyst is an organic bismuth catalyst or an isooctanoate catalyst.

7. The high-load holding-tack polyurethane removable adhesive according to claim 1, characterized in that, The said diisocyanate is MDI isocyanate.

8. A method for preparing a high-load adhesive polyurethane removable glue according to any one of claims 1 to 7, characterized in that, It includes the following steps: (1) Preparation of component A: Mix polyether polyol 1 and polyether polyol 2, dehydrate until the water content ≤ 0.05 wt.%, cool down and then add the anti-aging agent and the catalyst, and stir evenly to obtain component A; (2) Preparation of component B: Mix polyether polyol 3, hydroxypropyl methacrylate and diisocyanate, and react until the -NCO content is 10 - 11 wt.% to obtain component B; (3) Mix component A and component B evenly according to the mass ratio, inject into a mold, demold after closing the mold and curing to obtain a high load-bearing and sticky polyurethane removable adhesive.

9. The preparation method of the high-load holding-viscosity polyurethane repositionable adhesive according to claim 8, characterized in that, In the said step (1), cool down to 50 - 60 °C; in the said step (2), the reaction temperature is 75 - 90 °C.

10. The preparation method of the high-load holding-tack polyurethane transfer adhesive according to claim 8, characterized in that, In the said step (3), the temperature of the mold is 80 - 100 °C, and the time for closing the mold and curing is 3 - 5 min.

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