Polyurethane prepolymer and preparation method thereof

Abstract

The present invention provides a polyurethane prepolymer, comprising isocyanate, polyol and ion adsorbent, wherein the content of the ion adsorbent is not higher than 2% by mass percentage of the polyurethane prepolymer. The present invention solves the problem of instability of the polyurethane prepolymer in the prior art. At the same time, the present invention also provides a method for preparing the polyurethane prepolymer.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane materials, and in particular to a polyurethane prepolymer and a preparation method thereof. Background Art

[0002] Polyurethane is an organic polymer material formed by the reaction of polyisocyanates and polyols and having multiple carbamate segments. With the advancement of chemical research, product manufacturing, process technology and the continuous expansion of application fields, polyurethane materials have gradually become the sixth largest synthetic material in the world and can be widely used in light industry, construction, automobiles, textiles, electromechanics, ships, petrochemicals, metallurgy, energy and military industry.

[0003] Polyurethane prepolymers play an important role in the research and development of polyurethane materials. Their main application areas include polyurethane adhesives, coatings, elastomers, foams and fibers. Polyurethane prepolymers are reactive semi-finished products obtained by controlling the reaction of polyisocyanates and polyols in a certain ratio. Since there are many types of polyisocyanates and polyols and the reaction ratios are different, polyurethane prepolymers of various specifications can be made. However, polyurethane prepolymers have the problem of poor stability in the application of adhesives. Due to poor stability, polyurethane prepolymers will react with water vapor, and polyurethane prepolymers will also self-polymerize, thereby affecting the performance of downstream products. When the adhesive prepared using polyurethane prepolymers is used, it will affect the service life and process performance of the adhesive.

[0004] Therefore, it is necessary to provide a new polyurethane prepolymer and a preparation method thereof to solve the above-mentioned problems existing in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a polyurethane prepolymer and a preparation method thereof, so as to solve the problem of instability of the polyurethane prepolymer in the prior art.

[0006] To achieve the above object, the polyurethane prepolymer of the present invention comprises isocyanate, polyol and ion adsorbent, wherein the content of the ion adsorbent is not higher than 2% by mass percentage of the polyurethane prepolymer.

[0007] The beneficial effect of the polyurethane prepolymer of the present invention is that when the polyurethane prepolymer is used to prepare an adhesive and when the prepared adhesive is used, problems may occur in the preparation process and the use process of the adhesive due to the instability of the polyurethane prepolymer. There are various reasons for the instability of the polyurethane prepolymer. The present invention finds that the polyurethane prepolymer is unstable due to the presence of metal ions in the polyurethane prepolymer. Therefore, in order to solve the problem of the instability of the polyurethane prepolymer, the present invention adds an ion adsorbent to the polyurethane prepolymer and controls the content of the ion adsorbent to be no more than 2%, so that the ion adsorbent and the metal ions in the polyurethane prepolymer complex the metal ions through charge and dipole action and coordinated covalent bond action, thereby reducing the metal ions in the polyurethane prepolymer and finally improving the stability of the polyurethane prepolymer.

[0008] Optionally, the ion adsorbent includes at least one of dibenzo-18-crown-6, 15-crown-5 and 12-crown-4. The beneficial effect is that the crown ether molecule is electrically neutral as a whole, and the oxygen atom in the molecule has a higher electronegativity than the carbon atom and the hydrogen atom, so more electrons gather to the oxygen atom, so that the metal ions in the polyurethane prepolymer can be complexed through the charge and dipole action and the coordinated covalent bond action, thereby improving the stability of the polyurethane prepolymer.

[0009] Optionally, the content of the isocyanate is 12-20%, the content of the polyol is 78-87%, and the content of the ion adsorbent is 0.6-1.8% in terms of mass percentage of the polyurethane prepolymer. The beneficial effect is that the stability of the polyurethane prepolymer is improved by more than 10%.

[0010] Optionally, the isocyanate includes at least one of diphenylmethane diisocyanate, polymeric MDI, modified MDI and aliphatic isocyanate.

[0011] Optionally, the polymeric MDI includes at least one of Wanhua PM400 and Wanhua PM200, the modified MDI includes Wanhua CDMDI-100L, and the aliphatic isocyanate includes at least one of isophorone diisocyanate, hexamethylene diisocyanate and methylcyclohexane diisocyanate.

[0012] Optionally, the polyol includes at least one of polyether polyol, polyester polyol, polycarbonate polyol and oil polyol.

[0013] Optionally, the polyether polyol includes at least one of 330NG, N210 and MN3050D, the polyester polyol includes at least one of HF8001 and HF8025, the polycarbonate polyol includes at least one of POL-3195 and POL-12, and the oil polyol includes at least one of castor oil and SovermaL805.

[0014] Optionally, another object of the present invention is to provide a method for preparing a polyurethane prepolymer, comprising the following steps:

[0015] S0: Provide isocyanate, polyol and ion adsorbent;

[0016] S1: dehydrating the polyol to obtain a dehydrated polyol, and then adding isocyanate to carry out a prepolymerization reaction to obtain a polyurethane prepolymer before treatment;

[0017] S2: adding an ion adsorbent to the polyurethane prepolymer before treatment and mixing them thoroughly to obtain the polyurethane prepolymer.

[0018] The beneficial effect of the preparation method of the polyurethane prepolymer of the present invention is that the preparation method provided by the present invention is simple, and the prepared polyurethane prepolymer has high stability.

[0019] Optionally, the temperature of the prepolymerization reaction is 80-90 degrees Celsius, and the prepolymerization reaction is carried out under vacuum, and the pressure of the vacuum is ≤-0.09 MPa.

[0020] Optionally, the water content of the dehydrated polyol is ≤0.05%, the temperature of the dehydrated polyol is <60 degrees Celsius, and the temperature of the polyurethane prepolymer before treatment is <60 degrees Celsius. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a schematic diagram of a method for preparing a polyurethane prepolymer. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0023] An embodiment of the present invention provides a polyurethane prepolymer, comprising isocyanate, polyol and an ion adsorbent, wherein the content of the ion adsorbent is not higher than 2% by mass of the polyurethane prepolymer.

[0024] Specifically, when preparing an adhesive from a polyurethane prepolymer and when the prepared adhesive is used, problems may occur during the preparation process and the use process of the adhesive due to the instability of the polyurethane prepolymer. There are various reasons for the instability of the polyurethane prepolymer. The present invention finds that the polyurethane prepolymer is unstable due to the presence of metal ions in the polyurethane prepolymer. Therefore, in order to solve the problem of the instability of the polyurethane prepolymer, the present invention adds an ion adsorbent to the polyurethane prepolymer and controls the content of the ion adsorbent to be no more than 2%, so that the ion adsorbent and the metal ions in the polyurethane prepolymer complex the metal ions through charge and dipole effects and coordinated covalent bond effects, thereby reducing the metal ions in the polyurethane prepolymer and ultimately improving the stability of the polyurethane prepolymer.

[0025] In some embodiments of the present invention, the content of the ion adsorbent is any one of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8% and 1.9%.

[0026] In some embodiments of the present invention, the ion adsorbent includes at least one of dibenzo-18-crown-6, 15-crown-5 and 12-crown-4. The crown ether molecule is electrically neutral as a whole, and the oxygen atom in the molecule has a higher electronegativity than the carbon atom and the hydrogen atom, so more electrons gather to the oxygen atom, so that the metal ions in the polyurethane prepolymer can be complexed through charge and dipole action and coordinated covalent bonding, thereby improving the stability of the polyurethane prepolymer.

[0027] In some specific embodiments of the present invention, the molecular formula of dibenzo-18-crown-6 is C 20 H 24 O6, CAS No. 14187-32-7, English name Dibenzo-18-Crown-6; the molecular formula of the 15-crown ether-5 is C 10 H 20 O5, CAS No. 33100-27-5, English name 15-Crown-5; the molecular formula of 12-crown-4 is C8H 16 O4, CAS number is 294-93-9, English name is 12-Crown-4.

[0028] In some embodiments of the present invention, the content of the isocyanate is 12-20%, the content of the polyol is 78-87%, and the content of the ion adsorbent is 0.6-1.8%, based on the mass percentage of the polyurethane prepolymer, so that the stability of the polyurethane prepolymer is improved by more than 10%.

[0029] In some embodiments of the present invention, the isocyanate includes at least one of diphenylmethane diisocyanate, polymeric MDI, modified MDI and aliphatic isocyanate.

[0030] In some embodiments of the present invention, the polymeric MDI includes at least one of Wanhua PM400 and Wanhua PM200, the modified MDI includes Wanhua CDMDI-100L, and the aliphatic isocyanate includes at least one of isophorone diisocyanate, hexamethylene diisocyanate and methylcyclohexane diisocyanate.

[0031] In some embodiments of the present invention, the polyol includes at least one of polyether polyol, polyester polyol, polycarbonate polyol and oil polyol.

[0032] In some specific embodiments of the present invention, the polyether polyol includes at least one of 330NG, N210 and MN3050D, the polyester polyol includes at least one of HF8001 and HF8025, the polycarbonate polyol includes at least one of POL-3195 and POL-12, and the oil polyol includes at least one of castor oil and SovermaL805. In some specific embodiments, the manufacturer of the 330NG is Bluestar Dongda, the manufacturer of the N210 is Zhongshan Chemical, the manufacturer of the MN3050D is Bluestar Dongda, the manufacturer of the HF8001 and the manufacturer of the HF8025 are both Zhejiang Huafeng New Materials Co., Ltd., the manufacturer of the POL-3195 and the manufacturer of the POL-12 are both Qingdao Xinyutian Chemical Co., Ltd., and the manufacturer of the SovermaL805 is BASF.

[0033] Figure 1 The present invention is a schematic diagram of a method for preparing a polyurethane prepolymer.

[0034] The embodiments of the present invention refer to Figure 1 , provides a method for preparing a polyurethane prepolymer, comprising the following steps:

[0035] S0: Provide isocyanate, polyol and ion adsorbent;

[0036] S1: dehydrating the polyol to obtain a dehydrated polyol, and then adding isocyanate to carry out a prepolymerization reaction to obtain a polyurethane prepolymer before treatment;

[0037] S2: adding an ion adsorbent to the polyurethane prepolymer before treatment and mixing them thoroughly to obtain the polyurethane prepolymer.

[0038] Specifically, the preparation method provided by the present invention is simple, and the prepared polyurethane prepolymer has high stability.

[0039] In some embodiments of the present invention, the temperature of the prepolymerization reaction is 80-90 degrees Celsius, and the prepolymerization reaction is carried out under vacuum, and the pressure of the vacuum is ≤-0.09 MPa.

[0040] In some embodiments of the present invention, the water content of the dehydrated polyol is ≤0.05%, the temperature of the dehydrated polyol is <60 degrees Celsius, and the temperature of the polyurethane prepolymer before treatment is <60 degrees Celsius.

[0041] The technical solution of the embodiment of the present invention is described in detail below through specific examples.

[0042] Example

[0043] The preparation steps of comparative sample 1 and sample 1-6 are as follows:

[0044] Weigh the isocyanate, polyol and ion adsorbent according to Table 1, wherein the isocyanate is diphenylmethane diisocyanate, the polyol is polyether polyol 330NG, and the ion adsorbent is dibenzo-18-crown-6;

[0045] Dehydrating the polyol until the water content of the polyol is ≤0.05%, then cooling to <60 degrees Celsius to obtain a dehydrated polyol, then adding isocyanate to carry out a prepolymerization reaction under vacuum stirring at a temperature of 80-90 degrees Celsius until the NCO value reaches a theoretical value, and then stopping the prepolymerization to obtain a polyurethane prepolymer before treatment, wherein the theoretical value is 3.10%;

[0046] After the temperature of the polyurethane prepolymer before treatment is reduced to below 60 degrees Celsius, an ion adsorbent is added to the polyurethane prepolymer before treatment, and the polyurethane prepolymer is obtained after being fully mixed.

[0047] The prepared samples 1-6 and comparative sample 1 were subjected to stability test. The stability was characterized by the viscosity growth of samples 1-6 and comparative sample 1. The stability test steps were as follows: firstly, the initial viscosity of samples 1-6 and comparative sample 1 was tested. Then, samples 1-6 and comparative sample 1 were placed in a 50 degree Celsius oven for 7 days to accelerate the aging of samples 1-6 and comparative sample 1. Then, the viscosity of samples 1-6 and comparative sample 1 was tested to obtain the viscosity after aging. The test standard of the initial viscosity and the viscosity after aging was ASTMD-2196. The results of the initial viscosity, the viscosity after aging and the viscosity growth rate are shown in Table 1.

[0048] Tensile strength test: After placing samples 1-6 and comparative sample 1 at room temperature for 7 days, cured samples 1-6 and cured comparative sample 1 were obtained, and tensile strength tests were performed on the cured samples 1-6 and the cured comparative sample 1. The standard for the tensile strength test is GB / T-528. The results of the tensile strength of the cured samples 1-6 and the cured comparative sample 1 are shown in Table 1.

[0049] Table 1

[0050]

[0051] Note: Viscosity growth rate = (viscosity after aging - initial viscosity) / initial viscosity × 100%.

[0052] It can be seen from Table 1 that when no ion adsorbent is added to the polyurethane prepolymer, the viscosity growth rate is 42.81%. When the ion adsorbent is added to the polyurethane prepolymer, as the amount of ion adsorbent added increases, the viscosity growth rate first decreases and then increases. Therefore, by adding an appropriate amount of ion adsorbent to the polyurethane prepolymer, the viscosity growth of the polyurethane prepolymer can be reduced, thereby improving the stability of the polyurethane prepolymer. When the amount of ion adsorbent added is 3.2 grams, the viscosity growth rate of the polyurethane prepolymer is low, and the viscosity growth rate is small, indicating that the stability of the polyurethane prepolymer is good. The tensile strength of the cured sample 1-6 is not much different from the tensile strength of the cured comparative sample 1, so the addition of the ion adsorbent does not affect the tensile strength of the cured sample 1-6. The amount of ion adsorbent added should not be too little or too much. Too little or too much cannot maintain the stability of the polyurethane prepolymer, especially too much ion adsorbent is easy to cause material waste.

[0053] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A polyurethane prepolymer, characterized in that: The invention comprises isocyanate, polyol and ion adsorbent, wherein the content of the ion adsorbent is not higher than 2% by weight of the polyurethane prepolymer; the ion adsorbent comprises at least one of dibenzo-18-crown-6, 15-crown-5 and 12-crown-4.

2. The polyurethane prepolymer according to claim 1, characterized in that Calculated by mass percentage of the polyurethane prepolymer, the content of the isocyanate is 12-20%, the content of the polyol is 78-87%, and the content of the ion adsorbent is 0.6-1.8%.

3. The polyurethane prepolymer according to claim 1, characterized in that The isocyanate includes at least one of diphenylmethane diisocyanate, polymeric MDI, modified MDI and aliphatic isocyanate.

4. The polyurethane prepolymer according to claim 3, characterized in that The polymeric MDI includes at least one of Wanhua PM400 and Wanhua PM200, the modified MDI includes Wanhua CDMDI-100L, and the aliphatic isocyanate includes at least one of isophorone diisocyanate, hexamethylene diisocyanate and methylcyclohexane diisocyanate.

5. The polyurethane prepolymer according to claim 1, characterized in that The polyol includes at least one of polyether polyol, polyester polyol, polycarbonate polyol and oil polyol.

6. The polyurethane prepolymer according to claim 5, characterized in that The polyether polyol includes at least one of 330NG, N210 and MN3050D, the polyester polyol includes at least one of HF8001 and HF8025, the polycarbonate polyol includes at least one of POL-3195 and POL-12, and the oil polyol includes at least one of castor oil and SovermaL805.

7. A method for preparing a polyurethane prepolymer according to any one of claims 1 to 6, characterized in that: The following steps are involved: S0: Provide isocyanate, polyol and ion adsorbent; S1: dehydrating the polyol to obtain a dehydrated polyol, and then adding isocyanate to carry out a prepolymerization reaction to obtain a polyurethane prepolymer before treatment; S2: adding an ion adsorbent to the polyurethane prepolymer before treatment and mixing them thoroughly to obtain the polyurethane prepolymer.

8. The method for preparing a polyurethane prepolymer according to claim 7, characterized in that: The temperature of the prepolymerization reaction is 80-90 degrees Celsius, and the prepolymerization reaction is carried out under vacuum, and the pressure of the vacuum is ≤-0.09 MPa.

9. The method for preparing a polyurethane prepolymer according to claim 8, characterized in that: The water content of the dehydrated polyol is ≤0.05%, the temperature of the dehydrated polyol is <60 degrees Celsius, and the temperature of the polyurethane prepolymer before treatment is <60 degrees Celsius.

Images