CN111748255B - A kind of photothermal thermal insulation composite leather finishing agent based on Pickering emulsion polymerization method and preparation method thereof - Google Patents

Abstract

The invention discloses a photothermal thermal insulation type composite leather finishing agent based on Pickering emulsion polymerization method, a preparation method and application thereof, and belongs to the technical field of leather finishing agent preparation. In the present invention, the amphiphilicity of Ti ₃ C ₂ is regulated by polydopamine modification, and the amphiphilic polydopamine modified Ti ₃ C ₂ nanosheets, co-emulsifier, vinyl monomers and water are ultrasonically emulsified together to obtain a pre-emulsion. , using the Pickering emulsion polymerization method to initiate the polymerization of the pre-emulsion to obtain a photothermal thermal insulation composite leather finishing agent. _The photothermal thermal insulation composite leather finishing agent prepared by this method contains amphiphilic polydopamine modified _{Ti3C2 nanosheets} with synergistic photothermal conversion effect, which avoids the sedimentation when _Ti3C2 is introduced by the blending method. To solve the problem of agglomeration, the obtained photothermal thermal insulation composite leather finishing agent is then used in the leather finishing process to obtain leather products that rapidly self-heat under natural light, thereby reducing the total heat dissipation of the human body by reducing the temperature difference between the human body and the leather products. , to improve the warmth of leather products.

Description

A kind of photothermal thermal insulation composite leather finishing agent based on Pickering emulsion polymerization method and preparation method thereof

technical field

The invention belongs to the technical field of leather finishing agent preparation, and relates to a light-thermal thermal insulation type composite leather finishing agent based on a Pickering emulsion polymerization method and a preparation method thereof.

Background technique

Leather industry is one of the important pillar industries of my country's light industry. However, the poor warmth retention of leather limits the use of garment leather and shoe upper leather in cold outdoor environments, which is not conducive to the development of the leather industry. Improving the warmth retention of clothing leather in the outdoor environment in winter is an important development direction to realize the high value of leather. The development of thermal insulation leather finishing agent is expected to solve the defect of insufficient thermal insulation of clothing leather and break through the development shackles of clothing leather in the winter outdoor clothing market.

The existing design ideas of thermal insulation leather finishing agents are mainly to improve the thermal insulation performance of leather coatings by adding hollow nanomaterials to introduce air with low thermal conductivity. Chinese patent 201710210661.0A discloses a method for preparing a thermal insulation coating by introducing hollow titanium dioxide nanoparticles into a polyacrylate emulsion by a physical blending method. The method first prepares hollow titanium dioxide nanoparticles by a template-free method, but introduces them into In the polyacrylate emulsion, the obtained composite coating has certain thermal insulation performance, but the improvement of its thermal insulation performance is very limited. Usually, the thickness of the coating on the leather surface is only about 20 μm, and it is difficult to greatly improve the overall thermal insulation performance of the leather if the thickness is too low. Therefore, the practical application of the method of improving the thermal insulation performance of leather coatings by introducing hollow nanomaterials is not effective.

According to the principle of heat transfer, the temperature difference between the human body and the outside world is the fundamental reason for the heat dissipation of the human body. Increasing the surface temperature of clothing leather will reduce the total heat dissipation between the human body and the outside world, thereby improving the warmth retention of leather products. _Ti3C2 is a new type of _two -dimensional material with excellent photothermal conversion properties, capable of converting light energy into heat energy with a photothermal conversion rate close to 100%. In the early stage, the inventor introduced Ti ₃ C ₂ into the polyacrylate emulsion by the physical blending method, and obtained a composite leather finishing agent emulsion with photothermal conversion function. The relevant results were published in Langmuir (DOI: 10.1021/acs.langmuir.9b03943) . However, due to the high density of Ti ₃ C ₂ , the composite leather finishing agent emulsion prepared by blending method is prone to the problem of sedimentation and agglomeration during actual use, which affects the light-to-heat conversion performance and other properties of the leather finishing agent.

The current method of adding hollow nanoparticles to leather finishing agent by physical blending method cannot greatly improve the thermal insulation performance of leather coating. However, the method of introducing the photothermal conversion filler Ti ₃ C ₂ into the leather finishing agent emulsion by physical blending method cannot solve the problem of Ti ₃ C ₂ sedimentation and agglomeration. Therefore, the above methods are insufficient in improving the thermal insulation performance of leather.

SUMMARY OF THE INVENTION

In order to overcome the shortcoming of the above-mentioned prior art, the object of the present invention is to provide a kind of photothermal thermal insulation type composite leather finishing agent based on Pickering emulsion polymerization method and preparation method thereof, which can avoid the introduction of Ti by physical blending method through the preparation method of the present invention. The problem of sedimentation and agglomeration at ₃ C ₂ , the photothermal thermal insulation composite leather finishing agent prepared by this preparation method is used in the leather finishing process, and the surface temperature of the leather can be rapidly increased by light, thereby reducing the surface temperature of the human body and clothing leather. The temperature difference will eventually reduce the total heat dissipation of the human body.

In order to achieve the above object, the present invention adopts the following technical solutions to be realized:

The invention discloses a preparation method of a light-thermal thermal insulation type composite leather finishing agent based on a Pickering emulsion polymerization method, comprising the following steps:

1) using the self-polymerization reaction of dopamine hydrochloride to modify Ti ₃ C ₂ nanosheets to obtain amphiphilic polydopamine modified Ti ₃ C ₂ nanosheets;

2) using the amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets prepared in step 1) as an emulsifier, and cooperating with a co-emulsifier to perform ultrasonic emulsification of vinyl monomers in water to prepare a pre-emulsion;

3) Using Pickering emulsion polymerization method, in an inert atmosphere, using water as a solvent and ammonium persulfate as an initiator, the pre-emulsion obtained in step 2) is used to initiate polymerization to obtain a product system, and the pH value of the product system is adjusted to 7.5 after cooling. ~8.5, obtain a weakly basic product mixture, filter the weakly basic product mixture and collect the filtrate to prepare a light-thermal thermal insulation type composite leather finishing agent.

Preferably, in step 1), the mass ratio of dopamine hydrochloride and Ti ₃ C ₂ nanosheets is (1-5):1.

Preferably, in step 2), the co-emulsifier is n-butanol.

Preferably, the mass ratio of the amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheet, co-emulsifier, vinyl monomer and water is (0.1-0.5):(0.5-2):100:125.

Preferably, in step 2), the ultrasonic power is 600W, and the ultrasonic time is 10 minutes.

Preferably, in step 2), the vinyl monomer is a mixture of methyl methacrylate or styrene and butyl acrylate, and the mass ratio of methyl methacrylate or styrene to butyl acrylate is (4-6 ): (4 to 6).

Preferably, in step 3), the mass ratio of ammonium persulfate, vinyl monomer and water is 3:100:375.

The invention also discloses a photothermal heat preservation type composite leather finishing agent prepared by the above preparation method.

Preferably, by adjusting the content of the amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets, the heating rate of the leather after being finished with the heat-insulating composite leather finishing agent based on the Pickering emulsion polymerization method can be regulated.

Compared with the prior art, the present invention has the following beneficial effects:

The invention discloses a preparation method of a photothermal thermal insulation type composite leather finishing agent. _The preparation method prepares amphiphilic polydopamine modified _Ti3C2 nanosheets (amphiphilic polydopamine modified _Ti3C2 nanosheets) by modifying _Ti3C2 with polydopamine (PDA). Ti ₃ C ₂ @PDA nanosheets) and in-situ introduction of amphiphilic Ti ₃ C ₂ @PDA nanosheets by Pickering emulsion polymerization to prepare photothermal thermal insulation polyacrylate/Ti ₃ C ₂ @PDA composite leather finishing agent lotion. Among them, it is through the method of in situ introduction of amphiphilic _Ti3C2 @PDA nanosheets that the sedimentation problem of high _- density _Ti3C2 in the traditional physical blending method is solved. _At the same time, _Ti3C2 and _PDA have synergistic The photothermal conversion effect can quickly increase the surface temperature of the leather through light, thereby reducing the temperature difference between the human body and the surface of the garment leather, and finally reducing the total heat dissipation of the human body. It is beneficial to the stability of the emulsion of the finally obtained photothermal thermal insulation composite leather finishing agent. The existing method of introducing hollow nanoparticles into the leather finishing agent emulsion to improve the thermal insulation performance of the leather coating cannot greatly reduce the overall thermal insulation performance of the leather, but the photothermal leather finishing is prepared by introducing Ti ₃ C ₂ through the blending method. The problem of sedimentation and agglomeration of high-density Ti ₃ C ₂ cannot be avoided by the method of the agent.

Further, by selecting the mixed monomer system composed of methyl methacrylate or styrene and butyl acrylate as the reaction monomer, it is for the consideration of the choice of material hardness, because methyl methacrylate and styrene belong to Hard monomer, butyl acrylate is a soft monomer, so through the design of the mixed monomer system and the adjustment of the appropriate ratio, the coating formed by the photothermal thermal insulation composite leather finishing agent after use can have an appropriate softness. hardness.

The invention also discloses a light-thermal thermal insulation type composite leather finishing agent prepared by the method. _The photothermal thermal insulation composite leather finishing agent improves the dispersion of _Ti3C2 by in _- situ introduction of amphiphilic _Ti3C2 @PDA nanosheets with synergistic photothermal conversion effect by adopting the Pickering emulsion polymerization method. It solves the problem of sedimentation of high-density Ti ₃ C ₂ in the leather finishing agent emulsion, and obtains a uniform and stable photothermal thermal insulation composite leather finishing agent. The photothermal thermal insulation composite leather finishing agent of the present invention is used in the leather finishing process, and the leather after finishing is rapidly self-generated under natural lighting conditions by utilizing the synergistic photothermal conversion effect of Ti ₃ C ₂ and PDA, without the need for additional supply. It can achieve the purpose of reducing the total heat dissipation of the human body by reducing the temperature difference between the human body and the surface of the garment leather.

Further, since the amphiphilic Ti ₃ C ₂ @PDA nanosheets are photothermal conversion materials, the heating rate of the leather after finishing can be regulated by adjusting the proportion of the amphiphilic Ti ₃ C ₂ @PDA nanosheets. With the increase of the amount of amphiphilic Ti ₃ C ₂ @PDA nanosheets, the heating rate of the final finished leather is accelerated.

Description of drawings

Fig. 1 is the heating curve diagram of embodiment 1 of the present invention;

FIG. 2 is a heating curve diagram of Example 2 of the present invention.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only Embodiments are part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first", "second" and the like in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used may be interchanged under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

A method for a light-thermal thermal insulation type composite leather finishing agent based on the Pickering emulsion polymerization method disclosed in the invention, the steps are as follows:

(1) Using the self-polymerization reaction of dopamine hydrochloride under the weak alkaline condition of Tris buffer (pH=8.5) at room temperature to modify Ti ₃ C ₂ nanosheets, after 24 hours of reaction, suction filtration and rinse with water to prepare Amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets (amphiphilic Ti ₃ C ₂ @PDA nanosheets);

(2) Using amphiphilic Ti ₃ C ₂ @PDA nanosheets as emulsifier, and phacoemulsification with co-emulsifier n-butanol, vinyl monomers, and water to prepare a pre-emulsion, wherein the ultrasonic power is 600W, Ultrasound time is 10 minutes;

(3) Aqueous ammonium persulfate solution with a concentration of 0.8 wt% was prepared, 1/3 of the aqueous ammonium persulfate solution was added to a round-bottomed flask and heated to 75°C, nitrogen was introduced as a protective gas to remove air, and the remaining persulfuric acid was removed. The ammonium aqueous solution and the pre-emulsion were added dropwise into the round-bottomed flask simultaneously within 2 hours, and then cooled to room temperature naturally after being incubated for 2 hours. The pH value was adjusted to 7.5-8.5 with ammonia water, filtered and discharged, and the filtrate was collected to obtain photothermal insulation. Type polyacrylate/Ti ₃ C ₂ composite leather finishing agent emulsion was prepared to obtain a light-thermal thermal insulation type composite leather finishing agent.

Preferably, the pH value of the Tris buffer is 8.5, and the dosage ratio of Tris buffer, dopamine hydrochloride and Ti ₃ C ₂ is (1-5) L: (1-5) g: 1 g; the emulsifier amphiphilic Ti ₃ The mass ratio of C ₂ @PDA nanosheets, co-emulsifier, vinyl monomers and water is (0.1-0.5):(0.5-2):100:125; the vinyl monomers are methyl methacrylate and benzene The combination of a kind of ethylene and butyl acrylate, its mass ratio is (4-6): (4-6); The mass ratio of ammonium persulfate, vinyl monomer and water is 3:100:375; Ethylene The mass ratio of the base monomer to the amount of water in steps (2) and (3) is 1:5.

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

Example 1

Preparation of photothermal thermal insulation composite leather finishing agent based on Pickering emulsion polymerization:

(1) 100 mg of dopamine hydrochloride was added to 100 mL of Tris buffer at room temperature, and 100 mg of Ti ₃ C ₂ nanosheets were modified by its self-polymerization reaction under weak alkaline conditions (pH=8.5), and after 24 hours of reaction, Suction filtration and rinse with water to prepare amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets (amphiphilic Ti ₃ C ₂ @PDA nanosheets);

(2) Take 100 mg of the amphiphilic Ti ₃ C ₂ @PDA nanosheets obtained in step (1) as an emulsifier, mix it with 200 mg of n-butanol, 10 g of methyl methacrylate, 10 g of butyl acrylate, 25 g of water Ultrasonic emulsification to prepare a pre-emulsion, wherein the ultrasonic power is 600W, and the ultrasonic time is 10 minutes;

(3) 0.6g of ammonium persulfate was dissolved in 75g of water, 1/3 of the ammonium persulfate aqueous solution was added to the round-bottomed flask and heated to 75°C, nitrogen was introduced as a protective gas to remove air, and the remaining persulfuric acid was removed. The ammonium aqueous solution and the pre-emulsion prepared in step (2) were added dropwise to the round-bottomed flask simultaneously within 2 hours, cooled to room temperature naturally after being incubated for 2 hours, the pH value was adjusted to 8 with ammonia water, and the material was filtered and discharged to obtain a gray Emulsion of photothermal thermal insulation polyacrylate/Ti ₃ C ₂ @PDA composite leather finishing agent based on Pickering emulsion polymerization.

Spray application of photothermal thermal insulation composite leather finishing agent:

The above composite leather finishing agent emulsion was sprayed on the leather, the sizing amount was 20g/m ² , and the leather sample after finishing was placed in an oven at 105 ° C to dry for 3 minutes, and then taken out. Temperature 13°C.

As shown in Figure 1, under natural illumination in winter for only 20 minutes, the surface temperature of the leather sample after the photothermal thermal insulation composite finishing agent based on Pickering emulsion polymerization prepared in Example 1 increased to 27.7 °C, which was higher than that of the control group. 7.5°C higher.

Example 2

Preparation of photothermal thermal insulation composite leather finishing agent based on Pickering emulsion polymerization:

(1) 200 mg of dopamine hydrochloride was added to 200 mL of Tris buffer at room temperature, and 150 mg of Ti ₃ C ₂ nanosheets were modified by its self-polymerization reaction under weak alkaline conditions (pH=8.5), and after 24 hours of reaction, Suction filtration and rinse with water to prepare amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets (amphiphilic Ti ₃ C ₂ @PDA nanosheets);

(2) Taking 150 mg of the amphiphilic Ti ₃ C ₂ @PDA nanosheets obtained in step (1) as an emulsifier, and phacoemulsification with 500 mg of n-butanol, 30 g of styrene, 20 g of butyl acrylate, and 62.5 g of water , the pre-emulsion was prepared, wherein the ultrasonic power was 600W, and the ultrasonic time was 10 minutes;

(3) Dissolve 1.5 g of ammonium persulfate in 187.5 g of water, add 1/3 of the ammonium persulfate aqueous solution to the round-bottomed flask and heat it to 75°C, pass nitrogen as a protective gas to remove air, and remove the remaining The ammonium sulfate aqueous solution and the pre-emulsion were added dropwise into the round-bottomed flask simultaneously within 2 hours, and after being incubated for 2 hours, it was naturally cooled to room temperature, and the pH value was adjusted to 8 with ammonia water. Photothermal thermal insulation polyacrylate/Ti ₃ C ₂ @PDA composite leather finishing agent emulsion.

Spray application of photothermal thermal insulation composite leather finishing agent:

The above composite leather finishing agent emulsion was sprayed on the leather, the sizing amount was 30g/m ² , and the leather sample after finishing was placed in an oven at 105 ° C to dry for 3 minutes, and then taken out, and the leather sample was placed in the outdoor natural light. Temperature 13°C.

As shown in Figure 2, under natural illumination in winter for only 30 minutes, the surface temperature of the leather sample after the photothermal thermal insulation composite finishing agent based on Pickering emulsion polymerization prepared in Example 2 increased to 26.8 °C, which was higher than that of the control group. 6.3°C higher.

Example 3

Preparation of photothermal thermal insulation composite leather finishing agent based on Pickering emulsion polymerization:

(1) 300 mg of dopamine hydrochloride was added to 300 mL of Tris buffer at room temperature, and 100 mg of Ti ₃ C ₂ nanosheets were modified by its self-polymerization reaction under weak alkaline conditions (pH=8.5), and after 24 hours of reaction, Suction filtration and rinse with water to prepare amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets (amphiphilic Ti ₃ C ₂ @PDA nanosheets);

(2) Take 100 mg of the amphiphilic Ti ₃ C ₂ @PDA nanosheets obtained in step (1) as an emulsifier, and phacoemulsification with 500 mg of n-butanol, 23 g of styrene, 27 g of butyl acrylate, and 62.5 g of water , the pre-emulsion was prepared, wherein the ultrasonic power was 600W, and the ultrasonic time was 10 minutes;

(3) Dissolve 1.5 g of ammonium persulfate in 187.5 g of water, add 1/3 of the ammonium persulfate aqueous solution to the round-bottomed flask and heat it to 75°C, pass nitrogen as a protective gas to remove air, and remove the remaining The aqueous ammonium sulfate solution and the pre-emulsion were added dropwise into the round-bottomed flask simultaneously within 2 hours, and after being incubated for 2 hours, it was naturally cooled to room temperature, and the pH value was adjusted to 8.5 with ammonia water. Photothermal thermal insulation polyacrylate/Ti ₃ C ₂ @PDA composite leather finishing agent emulsion.

Example 4

Preparation of photothermal thermal insulation composite leather finishing agent based on Pickering emulsion polymerization:

(1) 500 mg of dopamine hydrochloride was added to 500 mL of Tris buffer at room temperature, and 200 mg of Ti ₃ C ₂ nanosheets were modified by its self-polymerization reaction under weak alkaline conditions (pH=8.5), and after 24 hours of reaction, Suction filtration and rinse with water to prepare amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets (amphiphilic Ti ₃ C ₂ @PDA nanosheets);

(2) Taking 200 mg of the amphiphilic Ti ₃ C ₂ @PDA nanosheets obtained in step (1) as an emulsifier, and phacoemulsification with 400 mg of n-butanol, 27 g of styrene, 23 g of butyl acrylate, and 62.5 g of water , the pre-emulsion was prepared, wherein the ultrasonic power was 600W, and the ultrasonic time was 10 minutes;

(3) Dissolve 1.5 g of ammonium persulfate in 187.5 g of water, add 1/3 of the ammonium persulfate aqueous solution to the round-bottomed flask and heat it to 75°C, pass nitrogen as a protective gas to remove air, and remove the remaining The ammonium sulfate aqueous solution and the pre-emulsion were added dropwise into the round-bottomed flask at the same time within 2 hours, and then cooled to room temperature naturally after being incubated for 2 hours, and the pH value was adjusted to 7.5 with ammonia water. Photothermal thermal insulation polyacrylate/Ti ₃ C ₂ @PDA composite leather finishing agent emulsion.

Example 5

Preparation of photothermal thermal insulation composite leather finishing agent based on Pickering emulsion polymerization:

(1) 150 mg of dopamine hydrochloride was added to 150 mL of Tris buffer at room temperature, and 50 mg of Ti ₃ C ₂ nanosheets were modified by its self-polymerization reaction under weak alkaline conditions (pH=8.5), and after 24 hours of reaction, Suction filtration and rinse with water to prepare amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets (amphiphilic Ti ₃ C ₂ @PDA nanosheets);

(2) Taking 50 mg of the amphiphilic Ti ₃ C ₂ @PDA nanosheets obtained in step (1) as an emulsifier, and phacoemulsification with 500 mg of n-butanol, 25 g of styrene, 25 g of butyl acrylate, and 62.5 g of water , the pre-emulsion was prepared, wherein the ultrasonic power was 600W, and the ultrasonic time was 10 minutes;

(3) Dissolve 1.5 g of ammonium persulfate in 187.5 g of water, add 1/3 of the ammonium persulfate aqueous solution to the round-bottomed flask and heat it to 75°C, pass nitrogen as a protective gas to remove air, and remove the remaining The aqueous ammonium sulfate solution and the pre-emulsion were added dropwise into the round-bottomed flask simultaneously within 2 hours, and after being incubated for 2 hours, it was naturally cooled to room temperature, the pH value was adjusted to 8 with ammonia water, and the material was filtered and discharged to obtain a light gray-green emulsion polymerization based on Pickering. Method of photothermal thermal insulation polyacrylate/Ti ₃ C ₂ @PDA composite leather finishing agent emulsion.

Example 6

Preparation of photothermal thermal insulation composite leather finishing agent based on Pickering emulsion polymerization:

(1) 100 mg of dopamine hydrochloride was added to 100 mL of Tris buffer at room temperature, and 100 mg of Ti ₃ C ₂ nanosheets were modified by its self-polymerization reaction under weak alkaline conditions (pH=8.5), and after 24 hours of reaction, Suction filtration and rinse with water to prepare amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets (amphiphilic Ti ₃ C ₂ @PDA nanosheets);

(2) Take 20 mg of the amphiphilic Ti ₃ C ₂ @PDA nanosheets obtained in step (1) as an emulsifier, mix with 100 mg of n-butanol, 10 g of methyl methacrylate, 10 g of butyl acrylate, 25 g of water Ultrasonic emulsification to prepare a pre-emulsion, wherein the ultrasonic power is 600W, and the ultrasonic time is 10 minutes;

(3) 0.6g of ammonium persulfate was dissolved in 75g of water, 1/3 of the ammonium persulfate aqueous solution was added to the round-bottomed flask and heated to 75°C, nitrogen was introduced as a protective gas to remove air, and the remaining persulfuric acid was removed. The ammonium aqueous solution and the pre-emulsion were added dropwise into the round-bottomed flask at the same time within 2 hours, cooled to room temperature naturally after being incubated for 2 hours, the pH value was adjusted to 7.5 with ammonia water, and the material was filtered to obtain a gray light based on Pickering emulsion polymerization method. Emulsion of thermal insulation polyacrylate/Ti ₃ C ₂ @PDA composite leather finish.

Example 7

Preparation of photothermal thermal insulation composite leather finishing agent based on Pickering emulsion polymerization:

(1) 500 mg of dopamine hydrochloride was added to 500 mL of Tris buffer at room temperature, and 100 mg of Ti ₃ C ₂ nanosheets were modified by its self-polymerization reaction under weak alkaline conditions (pH=8.5), and after 24 hours of reaction, Suction filtration and rinse with water to prepare amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets (amphiphilic Ti ₃ C ₂ @PDA nanosheets);

(2) Take 100 mg of the amphiphilic Ti ₃ C ₂ @PDA nanosheets obtained in step (1) as an emulsifier, mix it with 400 mg of n-butanol, 10 g of methyl methacrylate, 10 g of butyl acrylate, 25 g of water Ultrasonic emulsification to prepare a pre-emulsion, wherein the ultrasonic power is 600W, and the ultrasonic time is 10 minutes;

(3) 0.6g of ammonium persulfate was dissolved in 75g of water, 1/3 of the ammonium persulfate aqueous solution was added to the round-bottomed flask and heated to 75°C, nitrogen was introduced as a protective gas to remove air, and the remaining persulfuric acid was removed. The aqueous ammonium solution and the pre-emulsion were added dropwise into the round-bottomed flask simultaneously within 2 hours, cooled to room temperature naturally after being incubated for 2 hours, the pH value was adjusted to 8.5 with ammonia water, and the material was filtered to obtain a gray light based on Pickering emulsion polymerization. Emulsion of thermal insulation polyacrylate/Ti ₃ C ₂ @PDA composite leather finish.

Specifically, the mass ratio of the vinyl monomer to the water consumption in step (2) and step (3) is 1:5; by selecting the mass ratio of the vinyl monomer to the total amount of water to be 1: 5, the solid content in the emulsion of the thus obtained photothermal thermal insulation type composite leather finishing agent is 20wt%, which is due to the actual emulsification effect of the amphiphilic Ti ₃ C ₂ @PDA nanosheets (high solid content (35%). ) emulsion is difficult to prepare), if the solid content is too high, the effect of the emulsion system is not stable enough for the photothermal thermal insulation composite leather finishing agent with high solid content, so in order to achieve better practical use effect, vinyl-based The mass ratio of the total amount of monomer to water used was optimized to be 1:5.

Specifically, the present invention adopts the Pickering emulsion polymerization method for anionic emulsion polymerization. The anionic emulsion is acidic, the groups are not ionized, and the electrostatic repulsion is not enough to stably suspend the latex particles in water, which is prone to coagulation. By adjusting the pH value to a weak After being alkaline, the acidic groups are ionized, the surface of the latex particles is negatively charged, and the electrostatic repulsion becomes large enough to maintain stability under the action of electrostatic repulsion.

_In summary, the present invention discloses a method for preparing a photothermal thermal insulation type polyacrylate/Ti ₃ C _{2 @PDA} composite leather finishing agent by Pickering emulsion polymerization. The amphiphilic Ti ₃ C ₂ @PDA nanosheets, co-emulsifier n-butanol, vinyl monomers and water were phacoemulsified together to obtain a pre-emulsion, wherein the mass ratio of dopamine hydrochloride and Ti ₃ C ₂ was (1 -5):1, the mass ratio of Ti ₃ C ₂ , n-butanol, vinyl monomers and water is (0.1-0.5):(0.5-2):100:125, and 0.8wt% ammonium persulfate is configured The aqueous solution was used as the initiator solution, and the photothermal thermal insulation polyacrylate/Ti ₃ C ₂ @PDA composite leather finishing agent emulsion was prepared by Pickering emulsion polymerization. The mass ratio of ammonium persulfate to vinyl monomer was 3:100. The invention utilizes Pickering emulsion polymerization method to introduce in-situ amphiphilic Ti ₃ C ₂ @PDA nanosheets with synergistic photothermal conversion effect, avoids the problem of sedimentation and agglomeration when Ti ₃ C ₂ is introduced by blending method, and the composite finishing agent emulsion It is used in the leather finishing process to obtain leather products that quickly self-heat under natural light. By reducing the temperature difference between the human body and the leather products, the total heat dissipation of the human body can be reduced, thereby improving the warmth retention of the leather products.

The above content is only to illustrate the technical idea of the present invention, and cannot limit the protection scope of the present invention. Any modification made on the basis of the technical solution proposed in accordance with the technical idea of the present invention falls within the scope of the claims of the present invention. within the scope of protection.

Claims (3)

1. a preparation method based on the light-thermal insulation type composite leather finishing agent of Pickering emulsion polymerization, is characterized in that, comprises the following steps: 1) using the self-polymerization reaction of dopamine hydrochloride to modify Ti ₃ C ₂ nanosheets to obtain amphiphilic polydopamine modified Ti ₃ C ₂ nanosheets; 2) using the amphiphilic polydopamine-modified Ti ₃ C ₂ nanosheets prepared in step 1) as an emulsifier, and cooperating with a co-emulsifier to perform ultrasonic emulsification of vinyl monomers in water to prepare a pre-emulsion; 3) Using Pickering emulsion polymerization method, in an inert atmosphere, using water as a solvent and ammonium persulfate as an initiator, the pre-emulsion obtained in step 2) is used to initiate polymerization to obtain a product system, and the pH value of the product system is adjusted to 7.5 after cooling. ~8.5, obtaining a weakly basic product mixture, filtering the weakly basic product mixture and collecting the filtrate to obtain a light-thermal thermal insulation type composite leather finishing agent; In step 1), the mass ratio of dopamine hydrochloride and Ti ₃ C ₂ nanosheets is (1～5):1; In step 2), the ultrasonic power is 600W, the ultrasonic time is 10 minutes, the co-emulsifier is n-butanol, the amphiphilic polydopamine modified Ti ₃ C ₂ nanosheet, n-butanol, vinyl monomer and water mass ratio It is (0.1～0.5):(0.5～2):100:125, the vinyl monomer is a mixture of methyl methacrylate or styrene and butyl acrylate, methyl methacrylate or styrene and butyl acrylate The mass ratio of ester is (4～6):(4～6); In step 3), the mass ratio of ammonium persulfate, vinyl monomer and water is 3:100:375. 2. The photothermal thermal insulation type composite leather finishing agent obtained by the preparation method of claim 1. 3. the photothermal thermal insulation type composite leather finishing agent based on Pickering emulsion polymerization method according to claim 2, is characterized in that, by regulating the content of amphiphilic polydopamine modified Ti ₃ C ₂ nanosheets, it is possible to regulate and control the process described in the The heating rate of the leather after the thermal insulation composite leather finishing agent based on Pickering emulsion polymerization.

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