A multipurpose polyurethane adhesive tape and a process for its preparation

Abstract

The application relates to a multipurpose polyurethane adhesive tape and a preparation process thereof, and belongs to the polyurethane technical field. The polyurethane is obtained by mixing and curing A material and B material; according to the total mass of raw materials for preparing the A material, the components and mass fractions of the raw materials are as follows: 94-97% of polyglycol, 3-6% of diol chain extender; according to the total mass of raw materials for preparing the B material, the components and mass fractions of the raw materials are as follows: 45-52% of isocyanate, 48-55% of polyglycol; the polyglycol is a compound of polypropylene glycol and one or more selected from polybutylene glycol and polyethylene glycol; the mass ratio of the polypropylene glycol to the diol chain extender is 13-15:1; the number ratio of isocyanate in the B material to hydroxyl in the A material is 0.93-0.98. The polyurethane adhesive tape can realize the bonding of two-phase interfaces under various working conditions, has high weather resistance, and can self-heal when cracks occur in the polyurethane, thereby prolonging the service life.

Description

A multi-purpose polyurethane tape and its preparation process Technical Field

[0001] This invention relates to a multi-purpose polyurethane tape and its preparation process, belonging to the field of polyurethane technology. Background Technology

[0002] Polyurethane, renowned as the "fifth largest plastic" due to its excellent mechanical properties, good deformation ability, strong biocompatibility and solvent resistance, and diverse applications, is primarily made from isocyanates and polyols. The combination of various isocyanate and polyol structures allows for the design of the polyurethane's molecular structure based on its intended performance. Polyurethane materials are widely used in numerous fields, including the coal industry, transportation and construction, mechanical engineering, electronics and electrical engineering, and biomedicine. However, current research in the field of polyurethane bonding, even in low-cost systems and conventional formulations, still faces bottlenecks such as the lack of adhesive properties, poor weather resistance, and the difficulty in easily adjusting material properties.

[0003] Polyurethane materials in conventional formulations have almost no ability to adhere to objects. Existing methods to improve the adhesion of polyurethane materials include introducing dynamic bonds, introducing active fillers, or developing high-efficiency adhesive components. However, introducing substances with low bond energy, such as dynamic bonds, will reduce the anti-aging performance of the material, which is not conducive to its long-term use; the introduction of fillers will affect its bonding life due to dispersion or spontaneous migration of fillers in polyurethane; and developing its own adhesive components will increase costs and is not conducive to industrial production. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a multi-purpose polyurethane tape and its preparation process. Through improvements and innovations to the basic formulation, a multi-interface bonding, low-cost multi-purpose polyurethane tape was designed and prepared. The designed formulation and system not only possess adhesive properties compared to conventional formulations but also meet the needs of large-scale industrial production. The polyurethane tape can achieve bonding of two-phase interfaces under various working conditions (multi-interface bonding, multi-environment bonding) and has high weather resistance. Furthermore, the polyurethane tape can self-heal cracks, extending its service life.

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

[0006] A multi-purpose polyurethane tape, wherein the polyurethane is obtained by mixing and curing a mixture of component A and component B;

[0007] Based on the total mass of the raw materials used to prepare material A as 100%, the components and their mass fractions of each raw material are as follows: polydiol 94%~97%, diol chain extender 3%~6%;

[0008] Based on the total mass of the raw materials used to prepare material B as 100%, the components and their mass fractions of each raw material are as follows: isocyanate 45%~52%, polydiol 48%~55%;

[0009] The polydiol is a compound of polypropylene glycol (PPG) and one or more selected from polybutanediol (PTMG) and polyethylene glycol (PEG);

[0010] The mass ratio of polypropylene glycol (PPG) to glycol chain extender is 13~15:1;

[0011] The ratio of isocyanate ions in material B to hydroxyl ions in material A is 0.93~0.98.

[0012] Preferably, when mixing, the mass ratio of material A to material B is 8~11:10.

[0013] Preferably, the molecular weight of the polydiol is 960-1200.

[0014] Preferably, the amount of polypropylene glycol (PPG) added is 30% to 40% of the total mass of alcohols in components A and B.

[0015] Preferably, the isocyanate is one or more of diphenylmethane diisocyanate (MDI), toluene diisocyanate (HDI), and isophorone diisocyanate (IPDI).

[0016] Preferably, the diol chain extender is one or more of 1,4-butanediol (BDO), 1,3-propanediol (PDO), and ethylene glycol (EG).

[0017] A preparation process for the multi-purpose polyurethane tape of the present invention includes the following steps:

[0018] (1) Under the protection of protective gas, the isocyanate in material B is mixed with the polydiol and a prepolymerization reaction is carried out to obtain the prepolymerization reaction product, namely material B;

[0019] (2) Under air-isolated conditions, the B material and A material are preheated at 45~50°C and mixed, and after curing, a multi-purpose polyurethane tape is obtained.

[0020] Preferably, in step (1), the prepolymerization temperature is 80~85℃ and the prepolymerization time is 4h~8h.

[0021] Preferably, in step (2), the curing temperature is 70~90℃ and the curing time is 4h~8h.

[0022] Preferably, the isocyanate content of the prepolymer reaction product is determined by titration: the prepolymer reaction product is added to a toluene solution of di-n-butylamine, heated and stirred at 45-55°C to dissolve, and a titration sample solution is obtained; then, the isocyanate content in the prepolymer is obtained by titration using bromocresol green dissolved in isopropanol as an indicator.

[0023] Preferably, the ratio of the polyurethane prepolymer to isopropanol is 3-4 g: 150-250 mL; the volume ratio of the titration sample solution to the di-n-butylamine toluene solution is 2:1; and the ratio of the bromocresol green to the titration sample solution is 1 g: 1000 mL.

[0024] Preferably, the titrating reagent is 0.05~0.2 mol / L dilute hydrochloric acid.

[0025] Preferably, the mass relationship between the polydiol and the diol chain extender in materials B and A satisfies the following formula:

[0026] (m1×a%) / 42=R×((m2 / N1)×2+(m3 / N2)×2)

[0027] In the formula, m1, m2, and m3 are the masses of polydiol and glycol chain extender in component B and component A, respectively; N1 and N2 are the molecular weights of polydiol and glycol chain extender in component A, respectively; a% is the mass fraction of isocyanate in component B obtained by titration; R is the ratio of isocyanate to hydroxyl groups in the system, and R = 0.93~0.98.

[0028] Beneficial effects

[0029] This invention provides a multi-purpose polyurethane tape, which is a novel polyurethane material that can adhere to common materials such as glass and plastic cups. The high hydrogen bond content in the prepared polyurethane tape gives the material a strong ability to adhere to materials, including the ability to adhere to common materials underwater. Most importantly, the material has a low synthesis cost and can be mass-produced.

[0030] This invention provides a multi-purpose polyurethane tape, which is obtained by mixing and curing two components, A and B, at a certain R value (the ratio of isocyanate groups to hydroxyl groups in the material). The selection and dosage of each substance in components A and B ensure that the prepared polyurethane tape contains abundant free hydroxyl groups. These free hydroxyl groups can effectively form hydrogen bonds with substances on the surface of common materials, promoting adhesion between the two. During underwater bonding, the polypropylene glycol in the main chain of the prepared tape has side methyl groups, which can effectively remove moisture from the surface of the bonded object. At the same time, the free hydroxyl groups in the tape interact with the bonded object through hydrogen bonds and other interactions, achieving multi-interface underwater bonding under the combined effect of both. In an anhydrous environment, the side methyl groups of the polypropylene glycol in the main chain of the tape also remove some substances from the two-phase interface, improving the hydrogen bond formation efficiency and adhesion life between the free hydroxyl groups and the bonded object. The synergistic effect of both allows the prepared polyurethane tape to adhere to common objects under various working conditions.

[0031] This invention provides a multi-purpose polyurethane tape. It is necessary to control the polypropylene glycol content in the AB mixture. If the polypropylene glycol content is too low, the underwater adhesion of the prepared polyurethane tape will decrease or even disappear. If the polypropylene glycol content is too high, the polyurethane tape will have difficulty forming hydrogen bonds effectively between the two phase interfaces, which will also reduce the adhesion.

[0032] This invention provides a multi-purpose polyurethane tape. In the preparation of the polyurethane tape, the isocyanate in component B contains -NCO groups at both ends, and the polyol contains -OH groups at both ends. After initial synthesis of the prepolymer, both components can be stored for a long time at room temperature. Subsequently, different types of long-chain polymer segments (such as PTMG, PPG, etc.), crosslinking agents (such as 330N, etc.), and chain extenders (such as BDO, PDO, etc.) from component A can be added according to different production needs. These raw materials can polymerize at room temperature to produce polyurethane material. Afterwards, by adjusting the ratio of components A and B, finished products with different effects can be obtained. The method is simple, the experimental formula can be modified according to production needs, and it can be industrialized.

[0033] This invention provides a multi-purpose polyurethane tape. In the preparation of this polyurethane tape, maintaining the preheating temperature of the prepolymer at 45-50°C is crucial for its preservation. At temperatures of 55-80°C, the prepolymer will undergo self-polymerization. The prepolymer is end-capped with isocyanate (-NCO) groups. At room temperature, it tends to polymerize with hydroxyl groups in the chain extenders and crosslinking agents of the main raw materials. This polymerization method promotes the forward reaction and accelerates the reaction rate.

[0034] This invention provides a multi-purpose polyurethane tape. In the preparation of the polyurethane tape, it is necessary to control the isocyanate content of the prepolymer. If the isocyanate content is too low, the viscosity of the polyurethane will increase, making it difficult to extend the chain and shape the structure, thus making it impossible to obtain a polyurethane that can be used in practice. If the isocyanate content is too high, the reactivity will surge, making it difficult to control the molding and processing of the polyurethane. Attached Figure Description

[0035] Figure 1 shows photographs of the polyurethane adhesive materials at different interfaces described in Example 1.

[0036] Figure 2 shows photographs of the polyurethane adhesive materials described in Example 1 and Comparative Examples 1-2 under different environments and interfaces.

[0037] Figure 3 shows photographs of the polyurethane adhesive materials described in Comparative Examples 3-4 under different environments and interfaces.

[0038] Figure 4 shows photographs of the polyurethane adhesive materials in different environments and interfaces after being placed for six months as described in Example 4. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to specific embodiments.

[0040] Example 1

[0041] In this example, the molecular weight of polybutanediol is 960, and the molecular weight of polypropylene glycol is 1000. The mass ratio of polypropylene glycol to chain extender is 14.51:1. The sample has an R value of 0.93.

[0042] (1) Add 50g of diphenylmethane diisocyanate and 50g of polypropylene glycol to a 250mL three-necked flask, heat to 80℃ in a nitrogen atmosphere, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0043] (2) Take 0.3842g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1023mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 12.00%.

[0044] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0045] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutanediol and 1,4-butanediol to 70°C.

[0046] (4) Add 46.13g of polybutanediol and 1.48g of 1,4-butanediol from step (3) to the container in sequence, then add 42.96g of prepolymer and stir the solution at a stirring rate of 2000r / min for 60s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for 4h to cure, thus obtaining a multipurpose polyurethane tape.

[0047] Example 2

[0048] In this example, the molecular weight of both polybutane glycol and polypropylene glycol is 1000. The ratio of polypropylene glycol to chain extender is 14.79:1. The sample has an R value of 0.95.

[0049] (1) Add 50g of isophorone diisocyanate and 50g of polybutanediol to a 250mL three-necked flask, heat to 80℃ in a nitrogen atmosphere, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0050] (2) Take 0.3760g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat it at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1023mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 11.97%.

[0051] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0052] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutanediol and 1,4-butanediol to 70°C.

[0053] (4) Add 48.95g of polybutanediol and 1.47g of 1,4-butanediol from step (3) to the container in sequence, then add 43.51g of prepolymer and stir the solution at a stirring rate of 2000r / min for 12s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for 4h to cure, thus obtaining a multipurpose polyurethane tape.

[0054] Example 3

[0055] In this example, the molecular weight of polybutanediol is 1080, and the molecular weight of polypropylene glycol is 1000. The mass ratio of polypropylene glycol to chain extender is 13.75:1. The sample has an R value of 0.97.

[0056] (1) Add 50g toluene diisocyanate and 50g polybutanediol to a 250mL three-necked flask, heat to 80℃, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0057] (2) Take 0.3265g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat it at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1023mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 12.53%.

[0058] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0059] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutanediol and 1,4-butanediol to 70°C.

[0060] (4) Add 53.42g of polybutanediol and 1.54g of 1,4-butanediol from step (3) to the container in sequence, then add 42.35g of prepolymer and stir the solution at a stirring rate of 2000r / min for 12s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for 4h to cure, thus obtaining a multipurpose polyurethane tape.

[0061] Example 4

[0062] In this example, the molecular weight of polybutanediol is 1200, and the molecular weight of polypropylene glycol is 800. The mass ratio of polypropylene glycol to chain extender is 14.89:1. The sample has an R value of 0.96.

[0063] (1) Add 50g of diphenylmethane diisocyanate and 50g of polybutane glycol to a 250mL three-necked flask, heat to 80℃, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0064] (2) Take 0.3698g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat it at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1023mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 11.27%.

[0065] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0066] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutanediol and 1,4-butanediol to 70°C.

[0067] (4) Add 55.82g of polybutanediol and 1.50g of 1,4-butanediol from step (3) to the container in sequence, then add 44.68g of prepolymer and stir the solution at a stirring rate of 2000r / min for 12s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for curing for 4h to obtain a multipurpose polyurethane tape.

[0068] (5) Place the multipurpose polyurethane tape at room temperature for 6 months.

[0069] Example 5

[0070] In this example, the molecular weight of polybutanediol is 1200, and the molecular weight of polypropylene glycol is 900. The mass ratio of polypropylene glycol to chain extender is 13.25:1. The sample has an R value of 0.98.

[0071] (1) Add 50g hexamethylene diisocyanate and 50g polybutanediol to a 250mL three-necked flask, heat to 80℃, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0072] (2) Take 0.3965g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat it at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1023mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 12.76%.

[0073] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0074] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutadiene and 1,4-butanediol to 70°C.

[0075] (4) Add 50.53g of polybutanediol and 1.55g of 1,4-butanediol from step (3) to the container in sequence, then add 41.08g of prepolymer and stir the solution at a stirring rate of 2000r / min for 12s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for curing for 4h to obtain a multipurpose polyurethane tape.

[0076] (5) Place the multipurpose polyurethane tape at room temperature for 6 months.

[0077] Example 6

[0078] In this embodiment, the molecular weight of polybutanediol is 1200, and the molecular weight of polypropylene glycol is 1000. The mass ratio of polypropylene glycol to chain extender is 13.85:1. The sample has an R value of 0.95.

[0079] (1) Add 50g of diphenylmethane diisocyanate and 50g of polybutane glycol to a 250mL three-necked flask, heat to 80℃, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0080] (2) Take 0.3754g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat it at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1036mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 11.36%.

[0081] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0082] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutanediol and 1,4-butanediol to 70°C.

[0083] (4) Add 53.69g of polybutanediol and 1.58g of 1,4-butanediol from step (3) to the container in sequence, then add 43.76g of prepolymer and stir the solution at a stirring rate of 2000r / min for 12s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for 4h to cure, thus obtaining a multipurpose polyurethane tape.

[0084] (5) Place the multipurpose polyurethane tape at room temperature for 6 months.

[0085] Comparative Example 1

[0086] In this example, the molecular weight of polybutanediol is 900, and the molecular weight of polypropylene glycol is 1000. The mass ratio of polypropylene glycol to chain extender is 14.51:1. The sample has R=1.

[0087] (1) Add 50g of diphenylmethane diisocyanate and 50g of polypropylene glycol to a 250mL three-necked flask, heat to 80℃ in a nitrogen atmosphere, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0088] (2) Take 0.4263g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat it at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1023mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 12.36%.

[0089] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0090] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutanediol and 1,4-butanediol to 70°C.

[0091] (4) Add 42.63g of polybutanediol and 1.38g of 1,4-butanediol from step (3) to the container in sequence, then add 42.16g of prepolymer and stir the solution at a stirring rate of 2000r / min for 60s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for curing for 4h to obtain polyurethane elastomer.

[0092] Comparative Example 2

[0093] In this example, the molecular weight of polybutanediol is 1080, and the molecular weight of polypropylene glycol is 1000. The mass ratio of polypropylene glycol to chain extender is 14.51:1. The sample has an R value of 1.05.

[0094] (1) Add 50g of isophorone diisocyanate and 50g of polypropylene glycol to a 250mL three-necked flask, heat to 80℃ in a nitrogen atmosphere, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0095] (2) Take 0.3295g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat it at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1023mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 11.69%.

[0096] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0097] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutanediol and 1,4-butanediol to 70°C.

[0098] (4) Add 48.96g of polybutanediol and 1.54g of 1,4-butanediol from step (3) to the container in sequence, then add 41.06g of prepolymer and stir the solution at a stirring rate of 2000r / min for 60s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for curing for 4h to obtain polyurethane elastomer.

[0099] Comparative Example 3

[0100] In this example, the molecular weight of polybutanediol is 1000, and the molecular weight of polypropylene glycol is 900. The mass ratio of polypropylene glycol to chain extender is 11.09:1. The sample has an R value of 0.95.

[0101] (1) Add 50g toluene diisocyanate and 50g polypropylene glycol to a 250mL three-necked flask, heat to 80℃ in a nitrogen atmosphere, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0102] (2) Take 0.2295g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat it at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1023mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 12.44%.

[0103] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0104] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutanediol and 1,4-butanediol to 70°C.

[0105] (4) Add 43.69g of polybutanediol and 1.96g of 1,4-butanediol from step (3) to the container in sequence, then add 43.50g of prepolymer and stir the solution at a stirring rate of 2000r / min for 60s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for curing for 4h to obtain polyurethane elastomer.

[0106] Comparative Example 4

[0107] In this example, both polybutane glycol and polypropylene glycol have a molecular weight of 1000. The mass ratio of polypropylene glycol to chain extender is 18.45:1. The sample has an R value of 0.95.

[0108] (1) Add 50g of dimethylene diisocyanate and 50g of polypropylene glycol to a 250mL three-necked flask, heat to 80℃ in a nitrogen atmosphere, stir the raw materials at a rate of 200r / min to mix them evenly, and obtain polyurethane prepolymer after reacting for 4h.

[0109] (2) Take 0.3539g of the prepolymer obtained in step (1) and dissolve it in 25mL of di-n-butylamine in toluene solution. Heat at 50℃ for 20min to dissolve it completely. Add 4 drops of bromocresol blue indicator and then add 50mL of isopropanol to completely dissolve the indicator. Titrate with 0.1023mol / L dilute hydrochloric acid to find that the isocyanate content in the prepolymer is 11.59%.

[0110] The ratio of the mass (g) of bromocresol blue in the indicator to the volume (mL) of the solvent sodium hydroxide is 1:1000, and the concentration of sodium hydroxide is 0.1 mol / L.

[0111] (3) Preheat the prepolymer titrated in step (2) to 50°C, and preheat the dehydrated main raw materials polybutanediol and 1,4-butanediol to 70°C.

[0112] (4) Add 52.43g of polybutanediol and 1.18g of 1,4-butanediol from step (3) to the container in sequence, then add 43.55g of prepolymer and stir the solution at a stirring rate of 2000r / min for 60s; pour it into a polytetrafluoroethylene container and place it in an oven at 70℃ for 4h to cure, thus obtaining polyurethane elastomer.

[0113] The adhesiveness of the final products prepared in Examples 1-3 and Comparative Examples 1-4 was tested under different environments. Tap water at different temperatures was first added to test containers (plastic cups, glass beakers, and polytetrafluoroethylene dishes). The samples to be tested were placed in the containers, submerged in the water, and pressed against the side for five seconds before releasing. The solution was then stirred, and the adhesiveness of the samples was observed. The results are shown in Figures 1-3. The sample marked R=0.95 is the final product prepared in Example 1; the samples marked R=1 and R=1.05 are the final products prepared in Comparative Examples 1 and 2, respectively; and the samples marked 11:1 and 18:1 are the final products prepared in Comparative Examples 3 and 4, respectively. As can be seen from the figures, the polyurethane described in Example 1 can not only bond to the surfaces of common materials in a dry environment, but also exhibits adhesiveness to common objects in cold, room temperature, and hot water environments, and can bond two different types of substances on both sides. Polytetrafluoroethylene is a material commonly used in non-stick cookware, and the polyurethane described in Example 1 can still effectively bond it. The samples prepared within the R-value and two-component mass ratio range determined above demonstrated superior adhesive properties compared to other configurations of the base formulation. The four samples used as comparative examples did not exhibit adhesive properties, and the test results for samples in Examples 2 and 3 were similar to those in Example 1.

[0114] The adhesive properties of the final products prepared in Examples 4-6 were tested under different environments. First, tap water at different temperatures was added to the test containers: a plastic cup, a glass beaker, and a polytetrafluoroethylene dish. The sample to be tested was placed in the container, submerged in the water, and pressed down on the side for five seconds before releasing. The solution was then stirred, and the adhesive properties of the sample were observed. The results are shown in Figure 4. The sample marked with R=0.95 is the final product prepared in Example 4. As can be seen from the figure, the polyurethane in Example 4, after being stored for six months, exhibited adhesive properties to common objects in cold, room temperature, and hot environments, and could adhere to two different types of substances on both sides. Polytetrafluoroethylene is a material commonly used in non-stick cookware; the polyurethane in Example 4, after being stored for six months, only showed adhesive properties to it at room temperature. In summary, the sample, after being stored for six months, can still effectively adhere to glass and plastic in various environments, showing potential for long-term use. The test results for the samples in Examples 5-6 were similar to those in Example 4.

[0115] 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 multi-purpose polyurethane tape, characterized in that: The polyurethane tape was prepared by the following method, the steps of which included: (1) adding 50g of diphenylmethane diisocyanate and 50g of polypropylene glycol to a 250mL three-necked flask, heating to 80℃ in a nitrogen atmosphere, stirring the raw materials at a rate of 200r / min to mix them evenly, and reacting for 4h to obtain a polyurethane prepolymer; (2) taking 0.3842g of the prepolymer obtained in step (1) and dissolving it in 25mL of di-n-butylamine in toluene solution, heating it at 50℃ for 20min to fully dissolve it, adding 4 drops of bromocresol blue indicator and then adding 50mL of isopropanol to completely dissolve the indicator; titrating with 0.1023mol / L dilute hydrochloric acid to obtain an isocyanate content of 12.00% in the prepolymer; the bromocresol blue indicator was added to the prepolymer. The ratio of the mass of bromocresol blue in the phenol blue indicator to the volume of the solvent sodium hydroxide is 1g:1000mL, and the concentration of the sodium hydroxide is 0.1mol / L; (3) preheat the prepolymer obtained in step (1) to 50°C, and preheat the dehydrated polybutanediol and 1,4-butanediol to 70°C; (4) add 46.13g of polybutanediol and 1.48g of 1,4-butanediol from step (3) to the container in sequence, and then add 42.96g of prepolymer and stir the solution at a stirring rate of 2000r / min for 60s; pour it into a polytetrafluoroethylene container and place it in an oven at 70°C to cure for 4h to obtain a multipurpose polyurethane tape; wherein, the molecular weight of polybutanediol is 960 and the molecular weight of polypropylene glycol is 1000.

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