CN111234733B

CN111234733B - Eutectic solvent, environment-friendly adhesive and preparation method thereof

Info

Publication number: CN111234733B
Application number: CN202010112262.2A
Authority: CN
Inventors: 谭志坚; 董盛谊; 王朝云; 吴双根; 易永健; 蔡昌湧; 曾粮斌; 余旺; 汪洪鹰; 杨媛茹; 李懋
Original assignee: Institute of Bast Fiber Crops of CAAS
Current assignee: Institute of Bast Fiber Crops of CAAS
Priority date: 2020-02-24
Filing date: 2020-02-24
Publication date: 2021-07-02
Anticipated expiration: 2040-02-24
Also published as: CN111234733A

Abstract

The invention discloses a eutectic solvent, an environment-friendly adhesive and a preparation method thereof, wherein the eutectic solvent is formed by mixing a hydrogen bond donor and a hydrogen bond acceptor, the hydrogen bond donor is one of citric acid, malic acid and tartaric acid, and the hydrogen bond acceptor is cyclodextrin; the cyclodextrin is one of alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin; the malic acid is L- (-) -malic acid; the tartaric acid is L- (+) -tartaric acid. The preparation method of the environment-friendly adhesive is characterized by being prepared from any one of the eutectic solvents as a raw material. The eutectic solvent provided by the invention can be used for preparing the environment-friendly adhesive, and the prepared environment-friendly adhesive has the advantages of environmental friendliness, strong viscosity, simple preparation method, easily available raw materials, strong applicability, organic solvent resistance and the like, so that the eutectic solvent has great potential in the aspect of being used as the adhesive.

Description

Eutectic solvent, environment-friendly adhesive and preparation method thereof

Technical Field

The invention relates to the technical field of adhesives, and particularly relates to a eutectic solvent, an environment-friendly adhesive and a preparation method thereof.

Background

The adhesive is one of the most important auxiliary materials and is widely applied to packaging operation. Adhesives are sticky substances that, by virtue of their sticky properties, join two separate materials together. The adhesive is a general term for various stress materials which are used for connecting or jointing the same or different materials. There are three types, liquid, paste and solid.

The adhesives are natural adhesives, such as starch, protein, dextrin, animal glue, shellac, hide glue, rosin and other biological adhesives; also includes mineral adhesives such as asphalt. The other is artificially synthesized, and comprises inorganic adhesives such as water glass and the like, and organic adhesives such as synthetic resin, synthetic rubber and the like. The natural adhesive has the defects of narrow applicability, poor stability and the like; the synthetic adhesive has the defects of high cost, environmental pollution and the like.

Therefore, the development of the adhesive which has the advantages of wide application range, high stability, easily available raw materials, environmental friendliness and organic solvent resistance has important significance.

Deep Eutectic Solvents (DESs) are a new class of green solvents developed in recent years and are generally formed by mixing hydrogen bond donors (such as amides, carboxylic acids, polyols, and other compounds) and hydrogen bond acceptors (such as quaternary ammonium salts, etc.) in stoichiometric ratios, with the components associated by interacting ammonia bonds. The eutectic solvent has the characteristics of ionic liquid, so the eutectic solvent is also called as 'ionic liquid', most of the eutectic solvents have the advantages of low price, biodegradability, no toxicity, no harm, simple synthetic method, no use of organic solvent and the like, and are considered as substitutes of traditional volatile organic solvents. At present, most of researches on eutectic solvents are utilized in the fields of extraction separation, catalysis and the like, and few researches and reports are made on the application of the eutectic solvents in the aspect of environment-friendly adhesives.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a eutectic solvent, which can be used to prepare an environment-friendly adhesive.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the eutectic solvent is formed by mixing a hydrogen bond donor and a hydrogen bond acceptor, wherein the hydrogen bond donor is one of citric acid, malic acid and tartaric acid, and the hydrogen bond acceptor is cyclodextrin.

Preferably, the cyclodextrin is one of alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin.

Preferably, the malic acid is L- (-) -malic acid; the tartaric acid is L- (+) -tartaric acid.

The second purpose of the invention is to provide a preparation method of the environment-friendly adhesive, which is prepared by taking any one of the eutectic solvents as a raw material.

Preferably, the hydrogen bond acceptor and the hydrogen bond donor are mixed, heated and stirred to obtain the product.

Preferably, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1: 5 to 20.

Preferably, the heating temperature is 75-85 ℃, and preferably 80 ℃.

Preferably, the stirring time is 1-2 h, preferably 1.5 h.

The invention also aims to provide the environment-friendly adhesive prepared by any one of the preparation methods.

The invention has the beneficial effects that:

the eutectic solvent generally has higher viscosity, which is a big disadvantage limiting the application of the eutectic solvent in the field of extraction and separation, however, the invention provides a novel eutectic solvent based on cyclodextrin by utilizing the characteristic of high viscosity, which can be used for preparing environment-friendly adhesives, and the prepared environment-friendly adhesives have the advantages of environmental protection, strong viscosity, strong applicability, organic solvent resistance and the like, so the eutectic solvent has great potential in the aspect of being used as adhesives; the adhesive disclosed by the invention is simple in preparation method and easy in raw material acquisition.

Drawings

Fig. 1 is an infrared spectrum of six adhesives: (a) AM-1 and AM-2; (b) BM-1 and BM-2; (c) GM-1 and GM-2.

FIG. 2 shows three adhesives¹H NMR Spectrum (400MHz, D)₂O, room temperature): (a) AM-1; (b) BM-1; (c) GM-1.

Fig. 3 is an XRD spectrum of three adhesives: (a) AM-2; (b) BM-2; (c) GM-2.

Fig. 4 is a thermogravimetric analysis spectrum of three adhesives: (a) AM-2; (b) BM-2; (c) GM-2.

FIG. 5 is a graph of rheometer test results of adhesive AM 2: (a) frequency sweep test at 25 ℃, G' and G "are storage modulus and loss modulus, respectively; (b) carrying out frequency scanning test at 25 ℃, wherein eta is the composite viscosity; (c) performing temperature-changing rheological test at 25 ℃, wherein G 'and G' are respectively a storage modulus and a loss modulus; (d) and (3) carrying out variable temperature rheological test at 25 ℃, wherein eta is the composite viscosity.

FIG. 6 is a graph showing the adhesion strength of different adhesives to different materials, wherein a) is a glass plate, b) is a steel plate, c) is an organic glass plate, and d) is a polytetrafluoroethylene plate.

FIG. 7 is a graph showing the adhesion strength of different adhesives to different materials at different temperatures, wherein a) is glass, b) is steel, c) is organic glass, and d) is polytetrafluoroethylene.

Fig. 8 is a picture of adhesive BM-2 soaked in dichloromethane.

FIG. 9 is an experimental graph of adhesion performance test of the adhesive BM-2 to different biological tissues, wherein a) the graph and b) the graph are chicken hearts; c) the figure is chicken liver; d) the figure is chicken kidney; e) the figure is pigskin; f) FIG. is a pig bone; g) figure is a bovine articular bone; h) the figure is pork chop; i) the figure is pigskin; j) and k) the picture is pigskin.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Example 1

Respectively selecting citric acid, malic acid and tartaric acid as hydrogen bond donors; alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin are taken as hydrogen bond receptors. 22 adhesives based on eutectic solvents are prepared according to different proportions. See in particular table 1 below.

Table 1 adhesive component composition

Example 2

And weighing the hydrogen bond donor and the hydrogen bond acceptor according to the proportion in the table 1, adding the hydrogen bond donor and the hydrogen bond acceptor into a round-bottom flask, heating and stirring the mixture for 1 hour at the temperature of 80 ℃ until the solid is molten, and continuously stirring the mixture on a magnetic stirrer for 20 minutes to obtain 22 adhesives based on the eutectic solvent.

Example 3 Performance testing

The prepared adhesive was subjected to various performance tests as follows.

1. Adhesive characterization

The method comprises the first step of determining the chemical structure of 22 adhesives by adopting Fourier infrared spectroscopy and nuclear magnetic hydrogen spectroscopy, wherein the detection results of infrared spectroscopy of six representative adhesives AM1 and AM2, BM1 and BM2, and GM1 and GM2 are shown in figure 1, the detection results of nuclear magnetic resonance hydrogen spectroscopy of three representative adhesives AM-1, BM-1 and GM-1 are shown in figure 2, and the synthesized substances can be judged to be the required adhesives according to the results.

And secondly, researching the crystal form, the thermal stability and other physical properties of the 22-adhesive by adopting a powder X single crystal diffractometer and a thermogravimetric analyzer. Wherein XRD detection results of the three representative adhesives AM-2, BM-2 and GM-2 are shown in figure 3, and thermogravimetric analysis detection results of the three representative adhesives AM-2, BM-2 and GM-2 are shown in figure 4.

Thirdly, a rheometer is adopted to study amplitude and frequency scanning of the 22-degree-of-freedom adhesive at 25 ℃ and viscosity performance of the 22-degree-of-freedom adhesive at 15-80 ℃, a circulation test is carried out to obtain rheological data, and a detection result of a representative adhesive AM2 is shown in figure 5.

2. Tack Performance test

The first step, adopting a stretching instrument to test the adhesion performance of 22 adhesives to four materials, namely a glass plate, an organic glass plate, a polytetrafluoroethylene plate and a steel plate at 25 ℃ and 50% of humidity. The test results are shown in fig. 6, wherein a is a glass plate, b is a steel plate, c is an organic glass plate, and d is a polytetrafluoroethylene plate; the results show that various adhesives based on the cyclodextrin eutectic solvent have better adhesive performance to 4 materials.

And secondly, selecting three adhesives of AM2, BM2 and GM2 from 22 eutectic agents to test the adhesion performance of the adhesives to various materials (glass, organic glass, polytetrafluoroethylene and iron blocks) at different temperatures (-80-130 ℃). The test results are shown in FIG. 7, wherein a is glass, b is steel, c is plexiglass, and d is polytetrafluoroethylene. The result shows that the three adhesives of AM2, BM2 and GM2 have good adhesive performance to different materials at room temperature.

Thirdly, selecting three adhesives of AM2, BM2 and GM2 to test the adhesion performance of the adhesives to various materials (glass, organic glass, polytetrafluoroethylene and iron blocks) under different humidity conditions, wherein the test results are shown in the following tables 2 to 4.

Table 2: adhesion of adhesive AM-2 to 4 materials at different humidities (23,55 and 99%) (2 h at room temperature)

Table 3: adhesive BM-2 adhesion to 4 materials at different humidities (23,55 and 99%) (2 h at room temperature)

Table 4: adhesion of Adhesives GM-2 to 4 materials at different humidities (23,55 and 99%) (2 h at room temperature)

The fourth step: and (3) measuring the adhesive property of the adhesive after being soaked in a dichloromethane solution. The procedure was as follows, the adhered material was soaked in methylene chloride as shown in FIG. 8, taken out after soaking for 14 days, and the adhesion strength was measured using a tensile tester, and the results are shown in Table 5. The detection result shows that the adhesive has better organic solvent resistance.

Table 5: the two materials are adhered by three adhesives, and then are soaked in dichloromethane for 14 days to obtain the adhesive strength (the temperature is 25 ℃ and the humidity is 50%)

Fifthly, testing the adhesion performance of the adhesive BM-2 to biological tissues, as shown in figure 9, wherein a) and b) are chicken hearts; c) chicken liver; d) chicken kidney; e) pigskin; f) pig bone; g) bovine articular bone; h) pork ribs; i) pigskin; j) and k) pigs; it was found to have a good adhesion effect also on biological tissues.

In conclusion, the adhesive based on the eutectic solvent prepared by the invention has the advantages of environmental protection, strong viscosity, strong applicability, organic solvent resistance and the like, and has great economic and social benefits.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The preparation method of the environment-friendly adhesive is characterized by being formed by mixing a hydrogen bond donor and a hydrogen bond acceptor, wherein the hydrogen bond donor is one of citric acid, malic acid and tartaric acid, and the hydrogen bond acceptor is cyclodextrin; the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1: 10-20, heating to 75-85 ℃, and stirring to obtain the product; the cyclodextrin is one of alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin, and the malic acid is L- (-) -malic acid; the tartaric acid is L- (+) -tartaric acid.

2. The preparation method of the environment-friendly adhesive according to claim 1, wherein the stirring time is 1-2 h.

3. The environment-friendly adhesive prepared by the method according to any one of claims 1-2.