A wide-temperature-range polyurethane material with excellent adhesion properties and its preparation method

Abstract

This invention relates to a wide-temperature-range polyurethane material with excellent adhesion properties and its preparation method, belonging to the field of polyurethane technology. The polyurethane material is obtained by mixing and curing isocyanate and two polydiols of specific molecular weights in a certain ratio. The selection and dosage of these two components ensure the existence of a complete structural network in the prepared polyurethane material, further controlling the degree of phase separation and improving the adhesion properties of the polyurethane material.

Description

Technical Field

[0001] This invention relates to a wide-temperature-range polyurethane material with excellent bonding properties and its preparation method, belonging to the field of polyurethane technology. Background Technology

[0002] Polyurethane materials are a versatile polymer in both synthesis and application, and their superior properties enable their wide range of uses. On one hand, thermoplastic polyurethanes possess a tunable structure-property relationship, stemming from the presence of thermoplastically incompatible hard and soft segments. The soft segments provide flexibility to the polymer backbone, while the hard segments impart mechanical properties to the polymer.

[0003] Adhesive properties are not typical of polyurethane due to its low viscosity and low peel strength. Existing technologies involve adding tackifiers or blending with other polymers to adjust the glass transition temperature and reduce the elastic modulus of the polyurethane used in adhesives at room temperature. However, these adhesives develop very strong peel strength over time, leading to damage to the substrate upon removal. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a wide-temperature-range polyurethane material with excellent adhesive properties and a method for preparing the same. Through structural design of thermoplastic polyurethane, a thermoplastic polyurethane material with adhesive properties at room temperature was synthesized.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows.

[0006] A wide-temperature-range polyurethane material with excellent adhesion properties is obtained by curing diisocyanate and polyether diol. The total mass of the raw materials used to prepare the polyurethane material is 100%, and the raw material components and their mass fractions are as follows:

[0007] Diisocyanate 30%–40%;

[0008] Polyether diol 60%–70%;

[0009] The polyether diol is composed of two polyether diols with molecular weights of 250 and 650.

[0010] The molar ratio of the active -H in the polyether diol to the -NCO group in the diisocyanate is 1:0.83 to 0.9.

[0011] Preferably, the polyether diol is polyethylene glycol and / or polybutanediol.

[0012] Preferably, the mass fraction of diisocyanate is 30% to 35%, and the mass fraction of polyether diol is 60% to 65%.

[0013] Preferably, based on the total mass of the polyether diols (100%), the mass fraction of polyether diols with a molecular weight of 250 is 70%–90%, and the mass fraction of polyether diols with a molecular weight of 650 is 10%–30%. More preferably, based on the total mass of the polyether diols (100%), the mass fraction of polyether diols with a molecular weight of 250 is 70%–80%, and the mass fraction of polyether diols with a molecular weight of 650 is 20%–30%.

[0014] Preferably, the diisocyanate is toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), or isophorone diisocyanate (IPDI).

[0015] A method for preparing a wide-temperature-range polyurethane material with excellent bonding properties according to the present invention includes the following steps:

[0016] The polyether diol was subjected to vacuum dehydration to obtain the vacuum-dehydrated polyether diol.

[0017] In a protective gas atmosphere, diisocyanate is added to the vacuum-dehydrated polyether diol in 3 to 5 batches at 80 to 90°C, with an interval of 10 to 15 minutes between additions. After all the additions are completed, the reaction continues for 3 to 5 hours to obtain the prepolymer.

[0018] The prepolymer is cured at room temperature to obtain a wide-temperature-range polyurethane material with excellent adhesion properties.

[0019] Preferably, during vacuum dehydration, the vacuum degree is less than or equal to 0.1 MPa, the temperature is 110–120 °C, and the time is 2–4 h.

[0020] Preferably, the protective gas is nitrogen or an inert gas (the gaseous element corresponding to all group 0 elements in the periodic table).

[0021] Preferably, the curing temperature is 20-25℃ and the curing time is 36-48h.

[0022] Beneficial effects

[0023] This invention provides a wide-temperature-range polyurethane material with excellent bonding properties. The polyurethane material is obtained by mixing and curing isocyanate and two polydiols with specific molecular weights in a certain ratio. The selection and dosage of the two components can ensure that a complete structural network exists in the prepared polyurethane material, further controlling the phase separation degree of the polyurethane and improving the bonding performance of the polyurethane material.

[0024] This invention provides a polyurethane material with excellent adhesive properties, which is precisely compounded using a two-component polyether diol system with different molecular weights. By optimizing the ratio of two polyols with different molecular weights, this design achieves the following synergistic effects: significantly improving the internal friction coefficient between molecular chains; optimizing polar groups; and promoting the degree of phase separation between hard segment microdomains and soft segment matrix. This synergistic effect stems from the precise balance between the crystallinity of hard segments and the free volume of soft segments in the molecular design, providing a new solution for the development of high-performance polyurethane adhesives.

[0025] This invention provides a wide-temperature-range polyurethane material with excellent adhesion properties. The R-value (molar ratio of active -H groups in the polyether diol to -NCO groups at both ends of the diisocyanate) is between 0.83 and 0.9. This material has a low glass transition temperature and exhibits certain adhesive properties. Too low an R-value leads to increased polyurethane fluidity, making it difficult to mold and obtain a practically applicable polyurethane material; too high an R-value leads to a surge in reactivity, making it difficult to control the molding and processing of the polyurethane.

[0026] This invention provides a method for preparing a wide-temperature-range polyurethane material with excellent adhesion properties. The process is simple, the conditions are easy to control, and it is easy to achieve industrial production. Adding diisocyanate in batches during the prepolymerization process can keep the system in an excess state of polyether diol, which is beneficial to the preparation of polyurethane with high adhesion and wide temperature range. Attached Figure Description

[0027] Figure 1 The viscosity-temperature curves of the polyurethane materials described in Example 1 and Comparative Example 1 are shown.

[0028] Figure 2 The results show the bond strength of the polyurethane materials described in Example 1 and Comparative Example 1.

[0029] Figure 3 The damping temperature range results are for the polyurethane materials described in Example 1 and Comparative Example 1. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments.

[0031] Example 1

[0032] In this embodiment, the molecular weight of toluene diisocyanate is 174, and the molecular weights of polyether diol (polyethylene glycol) are 250 and 650. The mass ratio of the two polyethylene glycols is 7:3.

[0033] (1) In a three-necked flask, 120g of polyethylene glycol with a molecular weight of 250 and 30g of polyethylene glycol with a molecular weight of 650 were dehydrated at 110℃ and under vacuum of -0.1MPa for 4h.

[0034] (2) Under the protective atmosphere of N2, the temperature is raised to 80°C and stirred continuously (150r / min). 80g of toluene diisocyanate is added to the flask described in (1) in four batches with a time interval of 10min between additions. After the addition is completed, the reaction continues for 4h to obtain the prepolymer.

[0035] (3) The prepolymer obtained in (2) was cured at 25°C for 36 hours to obtain a wide-temperature-range polyurethane material with excellent bonding properties.

[0036] Example 2

[0037] In this embodiment, the molecular weight of toluene diisocyanate is 174, and the molecular weights of polyether diol (polyethylene glycol) are 250 and 650. The mass ratio of the two polyethylene glycols is 8:2.

[0038] (1) In a three-necked flask, 136g of polyethylene glycol with a molecular weight of 250 and 24g of polyethylene glycol with a molecular weight of 650 were dehydrated at 110℃ and under vacuum of -0.1MPa for 4h.

[0039] (2) Under the protective atmosphere of N2, the temperature was raised to 80°C and stirred continuously (150r / min). 87g of toluene diisocyanate was added to the flask described in (1) in four batches with a time interval of 15min between additions. After the addition was completed, the reaction continued for 4h to obtain the prepolymer.

[0040] (3) The prepolymer obtained in (2) was cured at 25°C for 36 hours to obtain a wide-temperature-range polyurethane material with excellent bonding properties.

[0041] Example 3

[0042] In this embodiment, the molecular weight of toluene diisocyanate is 174, and the molecular weights of polyether diol (polybutanediol) are 250 and 650. The mass ratio of the two polybutanediols is 9:1.

[0043] (1) In a three-necked flask, 126g of polybutane glycol with a molecular weight of 250 and 14g of polybutane glycol with a molecular weight of 650 were dehydrated at 110℃ and under vacuum of -0.1MPa for 4h.

[0044] (2) Under the protective atmosphere of N2, the temperature was raised to 85°C and stirred continuously (150r / min). 87g of toluene diisocyanate was added to the flask described in (1) in four batches with a time interval of 10min between additions. After the addition was completed, the reaction continued for 4h to obtain the prepolymer.

[0045] (3) The prepolymer obtained in (2) was cured at 25°C for 36 hours to obtain a wide-temperature-range polyurethane material with excellent bonding properties.

[0046] Comparative Example 1

[0047] In Comparative Example 1, the molecular weight of toluene diisocyanate was 174, and the molecular weight of polyether diol was 250. The R value of the system was 0.86.

[0048] (1) In a three-necked flask, 142g of polyether diol was dehydrated at 110℃ and under a vacuum of -0.1MPa for 4h.

[0049] (2) Heat to 80°C under a protective gas N2 atmosphere, add 86g of toluene diisocyanate to the flask described in (1), stir the raw materials at a rate of 150r / min to mix them evenly, and react with polyether diol for 4h.

[0050] (3) The product obtained in (2) was cured at 25°C for 24 hours to obtain polyurethane material.

[0051] Comparative Example 2

[0052] In this embodiment, the molecular weight of toluene diisocyanate is 174, and the molecular weight of polyether diol is 650. The R value of the system is 0.83.

[0053] Steps (1)-(3) are the same as in Comparative Example 1.

[0054] Comparative Example 3

[0055] In this embodiment, the molecular weight of toluene diisocyanate is 174, and the molecular weight of polyether diol is 2000. The R value of the system is 1.

[0056] Steps (1)-(3) are the same as in Comparative Example 1.

[0057] Comparative Example 4

[0058] In this embodiment, the molecular weight of toluene diisocyanate is 174, and the molecular weights of the polyether diols are 250 and 650. The mass ratio of the two polyether diols is 1:1.

[0059] Steps (1)-(3) are the same as in Comparative Example 1.

[0060] The viscosity of the final products prepared in Examples 1-3 and Comparative Examples 1-4 was tested using a parallel plate fluidization apparatus (Haake Mars 60, Germany). A constant-frequency variable-temperature test was performed at 1 Hz, with a test temperature range of -30℃ to 80℃. According to JGJ / T110-2017, the adhesive strength of the final products prepared in Examples 1-3 and Comparative Examples 1-4 was tested using an integrated adhesive strength tester (HC-6000C, Beijing Haichuang High-Tech Technology Co., Ltd., China). The threaded test block had dimensions of 40mm × 40mm × (6-8)mm, and the test temperature was ambient temperature (20-25℃). DMA testing was performed on the final products prepared in Examples 1-3 and Comparative Examples 1-4. The test conditions were compression mode, using a circular sample with a diameter of 8mm and a thickness of 2mm, and a constant-frequency variable-temperature test was performed at 10 Hz, with a test temperature range of -100℃ to 100℃.

[0061] The results of Example 1 and Comparative Example 1 are as follows: Figure 1-3 As shown, Example 1 exhibits a significantly different bond strength and loss factor peak shape compared to Comparative Example 1. Examples 2-4 have similar bonding effects and damping temperature range effects to Example 1.

[0062] When the R value is between 0.83 and 1, Comparative Examples 2 to 4 all exhibit similar bonding and damping temperature range effects as Comparative Example 1.

[0063] Examples 1-3, through appropriate control of the polyurethane chain structure, deepened the phase separation between hard and soft segments, exhibiting higher bonding strength at room temperature than Comparative Examples 1-4. Not only did they show higher loss factors in the low-temperature region, but they also exhibited higher damping in the high-temperature region, thus broadening the operating temperature range of polyurethane materials as damping materials. Furthermore, the glass transition temperature of the material could be controlled by changing the diol and isocyanate components used, resulting in excellent adhesion properties.

[0064] In summary, the invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered to be within the protection scope of this invention.

Claims

1. A wide-temperature-range polyurethane material with excellent bonding properties, characterized in that: The polyurethane material is obtained by curing diisocyanate and polyether diol, with the total mass of raw materials used to prepare the polyurethane material being 100%. The components and mass fractions of each raw material are as follows: Diisocyanate 30%~40%; Polyether diol 60%~70%; The polyether diol is composed of two polyether diols with molecular weights of 250 and 650; based on the total mass of the polyether diols as 100%, the mass fraction of the polyether diol with a molecular weight of 250 is 70% to 90%, and the mass fraction of the polyether diol with a molecular weight of 650 is 10% to 30%. The molar ratio of the active -H in the polyether diol to the -NCO group in the diisocyanate is 1:0.83~0.

9.

2. The wide-temperature-range polyurethane material with excellent bonding properties as described in claim 1, characterized in that: The polyether diol is polyethylene glycol and / or polybutanediol.

3. The wide-temperature-range polyurethane material with excellent bonding properties as described in claim 1, characterized in that: The mass fraction of diisocyanate is 30%~35%, and the mass fraction of polyether diol is 60%~65%.

4. The wide-temperature-range polyurethane material with excellent bonding properties as described in claim 1, characterized in that: Based on the total mass of the polyether diols as 100%, the mass fraction of polyether diols with a molecular weight of 250 is 70%~80%, and the mass fraction of polyether diols with a molecular weight of 650 is 20%~30%.

5. A wide-temperature-range polyurethane material with excellent bonding properties as described in claim 1, characterized in that: The diisocyanate is toluene diisocyanate, diphenylmethane diisocyanate, or isophorone diisocyanate.

6. A method for preparing a wide-temperature-range polyurethane material with excellent bonding properties as described in any one of claims 1 to 5, characterized in that: The method steps include: The polyether diol was subjected to vacuum dehydration to obtain the vacuum-dehydrated polyether diol. In a protective gas atmosphere, diisocyanate is added to the vacuum-dehydrated polyether diol in 3 to 5 batches at 80 to 90°C, with an interval of 10 to 15 minutes between additions. After all the additions are completed, the reaction continues for 3 to 5 hours to obtain the prepolymer. The prepolymer is cured at room temperature to obtain a wide-temperature-range polyurethane material with excellent adhesion properties.

7. The method for preparing a wide-temperature-range polyurethane material with excellent adhesion properties as described in claim 6, characterized in that: During vacuum dehydration, the vacuum level is less than or equal to 0.1 MPa, the temperature is 110~120℃, and the time is 2~4 hours.

8. The method for preparing a wide-temperature-range polyurethane material with excellent adhesion properties as described in claim 6, characterized in that: The protective gas is nitrogen or an inert gas.

9. The method for preparing a wide-temperature-range polyurethane material with excellent bonding properties as described in claim 6, characterized in that: The curing temperature is 20~25℃, and the curing time is 36~48h.

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