1. A preparation method of an oxidized chitosan/polydopamine composite cross-linking agent is characterized by comprising the following steps: the method comprises the following specific steps:

step one, obtaining an oxidized chitosan alkaline solution: putting powdered oxidized chitosan into a container, adding an alkaline solvent, and stirring to accelerate dissolution to obtain an oxidized chitosan alkaline solution;

step two, mixing and stirring: injecting the oxidized chitosan alkaline solution obtained in the step one into a stirring container, wherein the stirring speed is changed according to the gradual addition amount of dopamine hydrochloride, and the dopamine hydrochloride is synchronously added according to the compounding ratio of the dopamine hydrochloride and the oxidized chitosan;

step three, defoaming: pumping air from the inside of the closed stirring container by using a vacuum pump, and observing whether bubbles emerge through an observation window which is higher than the liquid level on the stirring container;

step four, standing: placing the mixed fluid defoamed in the third step in a low-temperature environment to obtain an oxidized chitosan polydopamine alkaline fluid;

step five, regeneration: placing the obtained oxidized chitosan polydopamine alkaline fluid in a non-solvent for regeneration;

step six, obtaining a finished product: and washing the oxidized chitosan polydopamine alkaline stream placed in the non-solvent with water to obtain the oxidized chitosan polydopamine composite cross-linking agent.

2. The preparation method of the oxidized chitosan/polydopamine composite cross-linking agent according to claim 1, wherein the preparation method comprises the following steps: the alkaline solvent contains lithium hydroxide, potassium hydroxide, urea and water, and the mass ratio of the components is 5:7:8: 80.

3. The preparation method of the oxidized chitosan/polydopamine composite cross-linking agent according to claim 1, wherein the preparation method comprises the following steps: and (3) freezing and storing the oxidized chitosan alkaline solution obtained in the first step at-40 to-25 ℃.

4. The preparation method of the oxidized chitosan/polydopamine composite cross-linking agent according to claim 1, wherein the preparation method comprises the following steps: the mass ratio of the dopamine hydrochloride and the oxidized chitosan which are compounded and synchronously added is 10-60%.

5. The preparation method of the oxidized chitosan/polydopamine composite cross-linking agent according to claim 1, wherein the preparation method comprises the following steps: and in the second step, the stirring speed of the stirrer is gradually increased along with the increase of the amounts of the dopamine hydrochloride and the chitosan oxide, the highest rotating speed is 20 revolutions per second, and the stirring time is 40-50 minutes.

6. The preparation method of the oxidized chitosan/polydopamine composite cross-linking agent according to claim 1, wherein the preparation method comprises the following steps: and in the third step, when no bubbles emerge from the liquid level within 2 to 3 minutes through the observation window, stopping the operation of the vacuum pump, sealing and standing for 20 to 30 minutes.

7. The preparation method of the oxidized chitosan/polydopamine composite cross-linking agent according to claim 1, wherein the preparation method comprises the following steps: and in the fourth step, the low-temperature environment is the low-temperature environment of 0-4 ℃ in the refrigerator, and the refrigerator is refrigerated for 10-36 hours.

8. The preparation method of the oxidized chitosan/polydopamine composite cross-linking agent according to claim 1, wherein the preparation method comprises the following steps: the non-solvent in the fifth step is widely used industrial alcohol.

9. The preparation method of the oxidized chitosan/polydopamine composite cross-linking agent according to claim 1, wherein the preparation method comprises the following steps: the concentration of the oxidized chitosan in the oxidized chitosan alkaline solution is 3-7 wt%.

10. The preparation method of the oxidized chitosan/polydopamine composite cross-linking agent according to claim 1, wherein the preparation method comprises the following steps: and judging whether the water washing is finished in the sixth step according to whether the monitoring fluid still contains the alkaline solvent component.

Background

The cross-linking agent is a substance which can play a bridging role between linear molecules so as to enable a plurality of linear molecules to be mutually bonded and cross-linked into a net structure, and has different names in different industries, such as: is customarily called "vulcanizing agent" in the rubber industry; known in the plastics industry as "curing agents", "hardeners"; the materials are called as 'curing agent', 'hardener' and the like in the adhesive or coating industry, and although the names are different, the reflected chemical properties and mechanisms are the same.

The traditional composite cross-linking agent is relatively complex to prepare, high in cost, relatively low in strength, and not excellent in performance, and some by-products can affect the environment. Therefore, the preparation method of the oxidized chitosan polydopamine composite cross-linking agent is provided for solving the problems.

Disclosure of Invention

The embodiment provides a preparation method of an oxidized chitosan polydopamine composite cross-linking agent, which is used for solving the problems in the prior art.

According to one aspect of the application, a preparation method of an oxidized chitosan polydopamine composite cross-linking agent is provided, which comprises the following steps:

step one, obtaining an oxidized chitosan alkaline solution: putting powdered oxidized chitosan into a container, adding an alkaline solvent, and stirring to accelerate dissolution to obtain an oxidized chitosan alkaline solution;

step two, mixing and stirring: injecting the oxidized chitosan alkaline solution obtained in the step one into a stirring container, wherein the stirring speed is changed according to the gradual addition amount of dopamine hydrochloride, and the dopamine hydrochloride is synchronously added according to the compounding ratio of the dopamine hydrochloride and the oxidized chitosan;

step three, defoaming: pumping air from the inside of the closed stirring container by using a vacuum pump, and observing whether bubbles emerge through an observation window which is higher than the liquid level on the stirring container;

step four, standing: placing the mixed fluid defoamed in the third step in a low-temperature environment to obtain an oxidized chitosan polydopamine alkaline fluid;

step five, regeneration: placing the obtained oxidized chitosan polydopamine alkaline fluid in a non-solvent for regeneration;

step six, obtaining a finished product: and washing the oxidized chitosan polydopamine alkaline stream placed in the non-solvent with water to obtain the oxidized chitosan polydopamine composite cross-linking agent.

Preferably, the alkaline solvent contains lithium hydroxide, potassium hydroxide, urea and water, and the mass ratio of the components is 5:7:8: 80.

Preferably, the oxidized chitosan alkaline solution obtained in the first step is stored at a temperature of between-40 ℃ and-25 ℃ in a freezing way.

Preferably, the dopamine hydrochloride and the oxidized chitosan are compounded and synchronously added in a mass ratio of 10-60%.

Preferably, in the second step, the stirring speed of the stirrer is gradually increased along with the increase of the amounts of the dopamine hydrochloride and the chitosan oxide, the maximum rotation speed is 20 revolutions per second, and the stirring time is 40 to 50 minutes.

Preferably, when no bubbles emerge in 2 to 3 minutes after the liquid level is observed through the observation window in the third step, the vacuum pump stops running, and the sealing is kept still for 20 to 30 minutes.

Preferably, the low-temperature environment in the fourth step is the low-temperature environment of 0-4 ℃ in the refrigerator, and the refrigerator is refrigerated for 10-36 hours.

Preferably, the non-solvent in the fifth step is widely used industrial alcohol.

Preferably, the concentration of the oxidized chitosan in the oxidized chitosan alkaline solution is 3-7 wt%.

Preferably, the criterion for judging whether the water washing is completed in the sixth step is to detect whether the alkaline solvent component is still contained in the fluid.

Through the above-mentioned embodiment of this application, can obtain the high and high compound cross-linking agent of concentration of intensity, adopt the vacuum pump to discharge the bubble to the fluid inside, it is rotten to reduce the fluid and take place the oxidation when depositing, adds alkaline solvent with powdered oxidized chitosan and obtains oxidized chitosan alkaline solution, reaches the effect of existing preparation at present, and powdered oxidized chitosan is stored more easily simultaneously, and environmental pollution is little, and product property can be excellent.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

Fig. 1 is a flow chart of a preparation method of the present application.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In this application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings. These terms are used primarily to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation.

Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meaning of these terms in this application will be understood by those of ordinary skill in the art as appropriate.

Furthermore, the terms "mounted," "disposed," "provided," "connected," and "sleeved" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The composite crosslinking agent in this embodiment may be suitable for encapsulation of an adhesive film, for example, the following POE encapsulation adhesive film for photovoltaic module encapsulation is provided in this embodiment.

The POE packaging adhesive film for packaging the photovoltaic module comprises the following raw materials in parts by mass in a formula system: the Melt Flow Rate (MFR) of the POE resin is 15g/10 min-40 g/10min, and the light transmittance is more than or equal to 90%; the composite cross-linking agent comprises three components, namely high-activity peroxide, low-activity peroxide and a cross-linking synergist, and is a mixture of the three components; the temperature of the high-activity peroxide is 130-170 ℃ when the decomposition half-life period is 1min, and more preferably 155-166 ℃; the temperature of the low-activity peroxide is 175-185 ℃ when the decomposition half-life period is 1min, and more preferably 178-181 ℃; the high-activity peroxide is one of 1, 1-di-tert-butylperoxy-3, 3, 5-trimethylcyclohexane, peroxy-2-ethylhexyl tert-amyl carbonate, tert-butylperoxy-2-ethylhexyl carbonate, 1-di-tert-butylperoxy cyclohexane and peroxy-2-tert-butyl ethylhexanoate; the low-activity peroxide is 2, 5-dimethyl-2, 5-dihexyl.

Of course, the present embodiment can also be used for packaging other adhesive film structures. The details are not repeated here, and the preparation method of the composite crosslinking agent of the embodiment of the present application is described below.

The first embodiment is as follows:

as shown in fig. 1, a preparation method of an oxidized chitosan polydopamine composite cross-linking agent comprises the following steps:

step one, obtaining an oxidized chitosan alkaline solution: putting powdered oxidized chitosan into a container, adding an alkaline solvent, and stirring to accelerate dissolution to obtain an oxidized chitosan alkaline solution;

step two, mixing and stirring: injecting the oxidized chitosan alkaline solution obtained in the step one into a stirring container, wherein the stirring speed is changed according to the gradual addition amount of dopamine hydrochloride, and the dopamine hydrochloride is synchronously added according to the compounding ratio of the dopamine hydrochloride and the oxidized chitosan;

step three, defoaming: pumping air from the inside of the closed stirring container by using a vacuum pump, and observing whether bubbles emerge through an observation window which is higher than the liquid level on the stirring container;

step four, standing: placing the mixed fluid defoamed in the third step in a low-temperature environment to obtain an oxidized chitosan polydopamine alkaline fluid;

step five, regeneration: placing the obtained oxidized chitosan polydopamine alkaline fluid in a non-solvent for regeneration;

step six, obtaining a finished product: and washing the oxidized chitosan polydopamine alkaline stream placed in the non-solvent with water to obtain the oxidized chitosan polydopamine composite cross-linking agent.

Further, the alkaline solvent contains lithium hydroxide, potassium hydroxide, urea and water, and the mass ratio of the components is 5:7:8: 80.

Further, the oxidized chitosan alkaline solution obtained in the first step is stored at a temperature of between 40 ℃ below zero and 25 ℃ below zero in a freezing way.

Further, the mass ratio of the dopamine hydrochloride and the oxidized chitosan which are compounded and synchronously added is 10-60%.

The preparation method of the oxidized chitosan polydopamine composite cross-linking agent has the advantages that: the composite cross-linking agent with high strength and high concentration can be obtained, and the vacuum pump is adopted to discharge air bubbles inside the fluid, so that the fluid is prevented from being oxidized and deteriorated during storage.

Example two:

as shown in fig. 1, a preparation method of an oxidized chitosan polydopamine composite cross-linking agent comprises the following steps:

step one, obtaining an oxidized chitosan alkaline solution: putting powdered oxidized chitosan into a container, adding an alkaline solvent, and stirring to accelerate dissolution to obtain an oxidized chitosan alkaline solution;

step two, mixing and stirring: injecting the oxidized chitosan alkaline solution obtained in the step one into a stirring container, wherein the stirring speed is changed according to the gradual addition amount of dopamine hydrochloride, and the dopamine hydrochloride is synchronously added according to the compounding ratio of the dopamine hydrochloride and the oxidized chitosan;

step three, defoaming: pumping air from the inside of the closed stirring container by using a vacuum pump, and observing whether bubbles emerge through an observation window which is higher than the liquid level on the stirring container;

step four, standing: placing the mixed fluid defoamed in the third step in a low-temperature environment to obtain an oxidized chitosan polydopamine alkaline fluid;

step five, regeneration: placing the obtained oxidized chitosan polydopamine alkaline fluid in a non-solvent for regeneration;

step six, obtaining a finished product: and washing the oxidized chitosan polydopamine alkaline stream placed in the non-solvent with water to obtain the oxidized chitosan polydopamine composite cross-linking agent.

Further, the alkaline solvent contains lithium hydroxide, potassium hydroxide, urea and water, and the mass ratio of the components is 5:7:8: 80.

Further, the oxidized chitosan alkaline solution obtained in the first step is stored at a temperature of-40 ℃ in a freezing way.

Further, the mass ratio of the dopamine hydrochloride and the oxidized chitosan which are compounded and synchronously added is 10%.

Further, in the second step, the stirring speed of the stirrer gradually increases with the increase of the amounts of the dopamine hydrochloride and the chitosan oxide, the maximum rotation speed is 20 revolutions per second, and the stirring time is 40 minutes.

And further, in the third step, when no bubbles emerge from the liquid surface within 2 minutes through the observation window, the vacuum pump stops running, and the sealing and the rest are carried out for 20 minutes.

The preparation method of the oxidized chitosan polydopamine composite cross-linking agent has the advantages that: the powdered oxidized chitosan is added into an alkaline solvent to obtain an oxidized chitosan alkaline solution, so that the effect of the existing preparation is achieved, and the powdered oxidized chitosan is easier to store.

Example three:

as shown in fig. 1, a preparation method of an oxidized chitosan polydopamine composite cross-linking agent comprises the following steps:

step one, obtaining an oxidized chitosan alkaline solution: putting powdered oxidized chitosan into a container, adding an alkaline solvent, and stirring to accelerate dissolution to obtain an oxidized chitosan alkaline solution;

step two, mixing and stirring: injecting the oxidized chitosan alkaline solution obtained in the step one into a stirring container, wherein the stirring speed is changed according to the gradual addition amount of dopamine hydrochloride, and the dopamine hydrochloride is synchronously added according to the compounding ratio of the dopamine hydrochloride and the oxidized chitosan;

step three, defoaming: pumping air from the inside of the closed stirring container by using a vacuum pump, and observing whether bubbles emerge through an observation window which is higher than the liquid level on the stirring container;

step four, standing: placing the mixed fluid defoamed in the third step in a low-temperature environment to obtain an oxidized chitosan polydopamine alkaline fluid;

step five, regeneration: placing the obtained oxidized chitosan polydopamine alkaline fluid in a non-solvent for regeneration;

step six, obtaining a finished product: and washing the oxidized chitosan polydopamine alkaline stream placed in the non-solvent with water to obtain the oxidized chitosan polydopamine composite cross-linking agent.

Further, the alkaline solvent contains lithium hydroxide, potassium hydroxide, urea and water, and the mass ratio of the components is 5:7:8: 80.

Further, the oxidized chitosan alkaline solution obtained in the first step is stored at a temperature of-25 ℃ in a freezing way.

Further, the mass ratio of the dopamine hydrochloride and the oxidized chitosan which are compounded and synchronously added is 60%.

Further, in the second step, the stirring speed of the stirrer gradually increases with the increase of the amounts of the dopamine hydrochloride and the chitosan oxide, the maximum rotation speed is 20 revolutions per second, and the stirring time is 50 minutes.

And further, in the third step, when no bubbles emerge from the liquid surface within 3 minutes through the observation window, the vacuum pump stops running, and the vacuum pump is sealed and stands still for 30 minutes.

Further, the low-temperature environment in the fourth step is the low-temperature environment at 4 ℃ in the refrigerator, and the refrigerator is refrigerated for 36 hours.

Further, the non-solvent in the fifth step is widely used industrial alcohol.

Further, the concentration of the oxidized chitosan in the oxidized chitosan alkaline solution is 7 wt%.

Further, the criterion for judging whether the water washing is completed in the sixth step is to detect whether the fluid still contains alkaline solvent component.

The preparation method of the oxidized chitosan polydopamine composite cross-linking agent has the advantages that: little environmental pollution and excellent product performance.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.