CN117209727A - Preparation method and application of hyperbranched succinate bio-based plasticizer - Google Patents

Abstract

The application discloses a preparation method and application of a hyperbranched succinate bio-based plasticizer. The preparation method comprises the following steps: (1) Carrying out melt polymerization reaction on glycerol and succinic acid under the action of a tin catalyst; (2) And (3) carrying out high-temperature vacuum treatment on the product obtained by melt polymerization to remove micromolecule monomers and byproduct water, wherein the temperature of the high-temperature vacuum treatment is the same as the melt polymerization reaction temperature in the step (1), so as to obtain the hyperbranched succinate bio-based plasticizer. The application provides application of a prepared hyperbranched succinate bio-based plasticizer in plasticized PVC. The hyperbranched succinic acid plasticizer synthesized by the application has excellent biocompatibility, has more excellent plasticizing effect when being used for plasticizing PVC, and can greatly improve the mechanical property and migration resistance of PVC materials.

Description

Preparation method and application of a hyperbranched succinate bio-based plasticizer

Technical field

The invention relates to a preparation method of a hyperbranched succinate bio-based plasticizer and its application in plasticized PVC, and belongs to the field of plastic additives.

Background technique

Polyvinyl chloride (PVC) is one of the most important thermoplastic polymers and is commonly used in various applications, namely construction, medical devices, toys and food packaging. However, this polymer has very limited applicability at room temperature due to low thermal stability and inherent rigidity (having a glass transition temperature (Tg) around 80°C). In order to adjust its properties and extend its scope of application, different additives are used, with special emphasis on low molecular weight plasticizers. Plasticizers are additives that are added to plastics to increase their softness, plasticity, and deformability. The introduction of plasticizers can improve the performance, cost-effectiveness and production efficiency of PVC. There are many types of plasticizers. Currently, the commonly used plasticizers mainly include phthalates, epoxidized soybean oil, epoxidized fatty acid esters, phosphates, polyamides, polycarbonates, and acetic acid. Propyl esters, etc. Phthalates are low molecular weight plasticizers that account for more than 80% of the total consumption of plasticizers used in the production of flexible PVC, mainly because of their good compatibility with PVC and competitive prices. However, due to their Due to their low molecular weight, their migration from the PVC matrix is inevitable. However, this undesirable migration leads to the deterioration of the material's mechanical properties and may also pose some risks to human health.

Therefore, some countries have begun to restrict the use of certain illegally added plasticizers and require plasticizers to undergo strict safety testing and supervision. In this sense, some strict restrictions have been introduced on the use of phthalates in certain applications.

In recent years, with the increasing awareness of environmental protection and sustainable development, bio-based plasticizers have gradually become a popular research field. Bio-based plasticizers are mainly made of natural or synthetic polymer materials obtained from renewable resources, and are renewable, degradable, and environmentally friendly. They have broad application prospects in plastics, rubber, coatings and other fields. At present, the synthesis process of biologically based linear polymer plasticizers is complex and difficult to achieve industrial production. Although the migration problem can be improved, the plasticizing efficiency is significantly reduced due to low chain mobility caused by entanglement or crystallization, and high addition amounts are required to achieve good plasticizing effects. Furthermore, their safety remains questionable, and the effects on humans of non-phthalate plasticizers developed as alternative plasticizers have not yet been proven.

Contents of the invention

In order to solve the problems existing in the above technology, the object of the present invention is to disclose a preparation method of hyperbranched succinate bio-based plasticizer and its application in plasticized PVC.

In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

In a first aspect, the present invention provides a method for preparing a hyperbranched succinate bio-based plasticizer, which includes the following steps:

(1) Carry out melt polymerization of glycerin and succinic acid under the action of tin catalyst; the feeding ratio of glycerin and succinic acid is calculated based on the molar ratio of hydroxyl and carboxyl groups contained in each: [-OH]:[-COOH] =1.7-2.3;

(2) The product obtained by melt polymerization is then subjected to high-temperature vacuum treatment to remove small molecular monomers and by-product water. The temperature of the high-temperature vacuum treatment is the same as the melt polymerization reaction temperature in step (1) to obtain hyperbranched succinate. bio-based plasticizer and stored in a vacuum oven.

In step (1) of the present invention, the raw material monomers glycerol and succinic acid are bio-based raw materials, and the feeding of glycerol and succinic acid is based on the molar ratio of their respective hydroxyl groups and carboxyl groups. When [-OH]:[-COOH] is less than a certain value Cross-linking reaction will occur, preferably [-OH]:[-COOH]=1.7-2.3, and optimally [-OH]:[-COOH]=1.7.

Preferably, the tin catalyst is dibutyltin oxide, and the added amount is 0.10wt%-0.20wt% of the total mass of glycerol and succinic acid, with the optimum being 0.15wt%.

Preferably, in step (1), the melt polymerization temperature is 150°C-180°C, more preferably the reaction temperature is 150°C; the reaction time is 8-20h, more preferably 20h.

Preferably, in step (1), the high-temperature vacuum treatment conditions are: the temperature is 150°C-180°C, more preferably 150°C, and the treatment time is 15min-45min, further preferably 30min.

Preferably, in step (2), the storage temperature in the vacuum drying oven is 50°C-70°C, and more preferably 60°C.

In a second aspect, the present invention provides an application of a hyperbranched succinate bio-based plasticizer prepared according to the preparation method described in the first aspect in plasticized PVC.

The specific application is as follows: dissolve the hyperbranched succinate bio-based plasticizer and polyvinyl chloride powder (PVC) in a solvent, stir and mix thoroughly and let it stand until the solution is clear and has no obvious bubbles, and finally the resulting solution is The film is titrated on the glass plate through solvent evaporation method, and finally the film is peeled off to obtain the PVC film.

In the present invention, commercially available products are selected as PVC.

Preferably, the mass ratio of the hyperbranched succinate bio-based plasticizer to PVC is 0.05-0.15, preferably 0.1.

Preferably, the solvent is tetrahydrofuran, ethanol, or dimethylformamide, and more preferably tetrahydrofuran.

Preferably, the solvent volatilization conditions are: drying in a blast oven at 45°C-80°C for 1-3 hours, and optimally drying in a blast oven at 80°C for 2 hours.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The synthesis route of the hyperbranched succinate bio-based plasticizer of the present invention is mature, the reaction device is simple, the operation is simple, the raw materials are easy to obtain, the raw materials are renewable, non-toxic and environmentally friendly, and the production cost is reduced;

(2) The hyperbranched succinate bio-based plasticizer of the present invention is produced by a melt polymerization method, does not require solvent conditions, eliminates intermediate product purification and other steps, and can be used for industrial large-scale production.

(3) The hyperbranched succinic acid plasticizer synthesized in the present invention has excellent biocompatibility.

(4) The hyperbranched succinate bio-based plasticizer synthesized in the present invention has a better plasticizing effect when used to plasticize PVC, and can greatly improve the mechanical properties and migration resistance of PVC materials.

Description of the drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the drawings needed to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. Those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting any creative effort. in:

Figure 1 is a hydrogen nuclear magnetic spectrum of the bio-based hyperbranched polyester plasticizer prepared in Example 1 of the present invention.

Figure 2 shows the cytotoxicity experimental results of the bio-based hyperbranched polyester plasticizer prepared in Example 1 of the present invention and the fluorescence photos of live cells and dead cells (green is live cells, red is dead cells), in which (a) group picture It is a blank control group, and group (b) shows the bio-based hyperbranched polyester plasticizer prepared in Example 1 of the present invention.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased on the market or can be prepared by known methods.

Example 1

Add 2.5g succinic acid and 2.2g glycerin (the molar ratio of hydroxyl and carboxyl groups is 1.7) into the reactor. The amount of dibutyltin oxidation catalyst is 0.15wt% of the total monomer mass. The reaction is carried out in an anhydrous and oxygen-free nitrogen environment. The reaction temperature is 150°C, the reaction time is 20h, and then vacuum treatment is performed at the same high temperature of 150°C for 0.5h to remove small molecular monomers and by-product water to obtain hyperbranched succinic acid polyester, which is stored in a 60°C vacuum oven. . The product is a succinic acid honey-like viscous substance with a yield of 85.2% and a number average molecular weight of 3369 Da.

The hydrogen nuclear magnetic spectrum of the product of Example 1 is shown in Figure 1. The hydrogen nuclear magnetic spectrum can prove that the synthesized polymer structure is a hydroxyl-terminated hyperbranched polyester.

A biocompatibility test was conducted on the hyperbranched succinic acid plasticizer synthesized in Example 1 of the present invention according to GB/T 16886.5-2017. The experimental results are shown in Figure 2. At a concentration of 0.2 mg/ml, the cell activity was 85%. Meet the requirements of this standard (cell activity is greater than 70%).

Example 2

Add 2.5g succinic acid and 2.2g glycerin (the molar ratio of hydroxyl and carboxyl groups is 1.7) into the reactor. The amount of dibutyltin oxidation catalyst is 0.15wt% of the total monomer mass. The reaction is carried out in an anhydrous and oxygen-free nitrogen environment. The reaction temperature is 150°C, the reaction time is 12h, and then vacuum treatment is performed at the same high temperature of 150°C for 0.5h to remove small molecular monomers and by-product water to obtain hyperbranched succinic acid polyester, which is stored in a 60°C vacuum oven. . The product was a succinic acid honey-like viscous substance with a yield of 77.6% and a number average molecular weight of 2773 Da.

Example 3

Add 2.5g succinic acid and 2.2g glycerin (the molar ratio of hydroxyl and carboxyl groups is 1.7) into the reactor. The amount of dibutyltin oxidation catalyst is 0.15wt% of the total monomer mass. The reaction is carried out in an anhydrous and oxygen-free nitrogen environment. The reaction temperature is 150°C, the reaction time is 8h, and then vacuum treatment is performed at the same high temperature of 150°C for 0.5h to remove small molecular monomers and by-product water to obtain hyperbranched succinic acid polyester, which is stored in a 60°C vacuum oven. . The product was a succinic acid honey-like viscous substance with a yield of 82.9% and a number average molecular weight of 2575 Da.

Example 4

Add 2.5g succinic acid and 2.6g glycerin (the molar ratio of hydroxyl and carboxyl groups is 2.0) into the reactor. The amount of dibutyltin oxidation catalyst is 0.15wt% of the total mass of the monomer. The reaction is carried out in an anhydrous and oxygen-free nitrogen environment. The reaction temperature is 150°C, the reaction time is 20h, and then vacuum treatment is performed at the same high temperature of 150°C for 0.5h to remove small molecular monomers and by-product water to obtain hyperbranched succinic acid polyester, which is stored in a 60°C vacuum oven. . The product is a succinic acid honey-like viscous substance with a yield of 79.3% and a number average molecular weight of 2415 Da.

Example 5

Add 2.5g succinic acid and 2.4g glycerol (the molar ratio of hydroxyl and carboxyl groups is 2.3) into the reactor. The amount of catalyst used to oxidize dibutyltin is 0.15wt% of the total mass of the monomer. The reaction is carried out in an anhydrous and oxygen-free nitrogen-protected environment. The reaction temperature is 150°C, the reaction time is 20h, and then vacuum treatment is performed at the same high temperature of 150°C for 0.5h to remove small molecular monomers and by-product water to obtain hyperbranched succinic acid polyester, which is stored in a 60°C vacuum oven. . The product is a succinic acid honey-like viscous substance with a yield of 78.6% and a number average molecular weight of 2199 Da.

Example 6

Add 2.5g succinic acid and 2.2g glycerin (the molar ratio of hydroxyl and carboxyl groups is 1.7) into the reactor. The amount of dibutyltin oxidation catalyst is 0.15wt% of the total monomer mass. The reaction is carried out in an anhydrous and oxygen-free nitrogen environment. The reaction temperature is 180°C, the reaction time is 20h, and then vacuum treatment is performed at the same high temperature of 150°C for 0.5h to remove small molecular monomers and by-product water to obtain hyperbranched succinic acid polyester, which is stored in a 60°C vacuum oven. . The product is a succinic acid honey-like viscous substance with a yield of 80.7% and a number average molecular weight of 2983 Da.

Comparative example 1

Add 2.5g succinic acid and 2.23g ethylene glycol to the reactor. The amount of catalyst used to oxidize dibutyltin is 0.15wt% of the total mass of the monomer. The reaction is carried out in an anhydrous and oxygen-free nitrogen-protected environment. The reaction temperature is 150°C. The time is 12h. After the reactor temperature drops, use 50ml of the solvent dimethylformamide to dissolve the polymer, pour it into a beaker and add a magnet. Add 0.5g sodium hydroxide and 0.5g activated carbon, stir for 2h, and filter with 50μm filter paper. Filter the mixture and use a 20ml glass bottle to collect the filtrate. Move the glass bottle containing the filtrate into a vacuum oven at 80°C and dry it for 24 hours to remove the solvent in the filtrate. Then, a light yellow waxy linear succinate is obtained. And stored in a vacuum oven at 60°C, the yield was 77.6%, and the number average molecular weight was 1936Da.

Comparative example 2

Add 2.5g succinic acid and 1.69g glycerol (the molar ratio of hydroxyl and carboxyl groups is 1.3) into the reactor. The amount of dibutyltin oxidation catalyst is 0.15wt% of the total mass of the monomer. The reaction is carried out in an anhydrous and oxygen-free nitrogen environment. The reaction temperature is 150°C, the reaction time is 20h, and then vacuum treatment is performed at the same high temperature of 150°C for 0.5h to remove small molecular monomers and by-product water to obtain hyperbranched succinic acid polyester, which is stored in a 60°C vacuum oven. . The product is a gum-like viscous substance with a yield of 66.2% and a number average molecular weight of 2530 Da.

Comparative example 3

Commercial dioctyl phthalate (Sinopharm Chemical Reagent Co., Ltd.).

Example 7

The substances obtained in Example 1 and Comparative Examples 1 and 2 were used as plasticizers to plasticize PVC to obtain plastic test pieces. The specific preparation method is: dissolve 0.3g plasticizer, 3g PVC and 50ml tetrahydrofuran in a beaker container, stir evenly, and let stand for 20 minutes. Use the titration film-forming method to drop-coat the mixture in the container on a 50cm*80cm glass plate, dry it in a blast oven at 80°C for 2 hours, and remove the film after the glass plate is cooled in the air to obtain a PVC film. . For comparison, pure PVC films without plasticizer were prepared. The prepared films were used for performance testing.

Conduct plasticization performance evaluation, mechanical properties and migration performance tests on the obtained PVC film:

(1) Plasticizing performance evaluation

The plasticizer-plasticized PVC film of Example 1 and Comparative Example 1 and the pure PVC film were tested using a differential scanning calorimeter to determine the glass transition temperature of the film to evaluate the plasticizer effect of the plasticizer. The results As shown in Table 1, it can be seen from Table 1 that compared with the plasticizer-plasticized PVC film and pure PVC film of Comparative Example 1, the glass transition of the plasticizer-plasticized PVC product of Example 1 The temperature decreases significantly (the lower the glass transition temperature, the better the plasticizing effect). This is because the molecular structure of hyperbranched plasticizers is relatively complex and usually contains multiple branched structures. These branched structures can be used in PVC. A certain degree of randomness and activity is introduced into the molecular chain, thereby reducing the interaction force of the PVC molecular chain, increasing the reactivity of the molecular chain, and making the PVC molecules more susceptible to glass transition. At the same time, the hyperbranched plasticizer can form a strong interaction with PVC molecules, but has a small impact on the main chain mobility of the PVC molecular chain. This means that the hyperbranched structure plasticizer will not hinder the movement of the main chain of the PVC chain, thereby lowering the glass transition temperature of the PVC chain. The interaction force of linear plasticizers is relatively weak and has a greater impact on the mobility of the main chain of the PVC chain. Therefore, the glass transition temperature of the PVC chain is relatively high.

Table 1: DSC test result table

(2) Mechanical property evaluation

The PVC film plasticized by the plasticizer of Example 1, Comparative Example 1, and Comparative Example 2 was cut to obtain a stretched film sample, and a tensile test was performed according to relevant standards to evaluate its mechanical properties. The results obtained are shown in Table 2. It can be seen from Table 2 that compared with the PVC products plasticized by the plasticizer of Comparative Examples 1 and 2, the mechanical strength of the PVC products plasticized by the plasticizer of Example 1 is higher. High, which shows that the hyperbranched succinic acid plasticizer provides better plasticizing effect for PVC and also improves its tensile strength. This is because the high molecular weight polymer or resin in the hyperbranched plasticizer has cross-linking ability, which can form stronger connections between PVC molecular chains through cross-linking with PVC molecular chains, thus improving the mechanics of PVC products. strength. At the same time, the high molecular weight polymer or resin in the hyperbranched structure plasticizer has high ductility and can play a certain tensile and tear resistance role when PVC products are subjected to external forces, thus improving the mechanical strength of PVC products. Therefore, hyperbranched structural plasticizers not only provide better plasticizing effects for PVC products, but also significantly increase the tensile strength of the material. This gives hyperbranched structural plasticizers significant advantages in the application of PVC products.

Table 2: Tensile test results table

(3)Migration performance evaluation

The migration properties of the PVC films plasticized by the plasticizers of Example 1, Comparative Example 1, and Comparative Example 2 were studied according to ASTM D1239-14. The specific steps are: immerse the PVC test piece in deionized water and place it at 50°C for 24 hours. Then take it out, wash it with ethanol, place it in the oven to dry at 40°C for 2 hours, move it into a desiccator, cool it to room temperature, and weigh it. Calculate the mass loss of the PVC test piece before and after the experiment (there are only PVC and plasticizer in the mixture, so it can be considered The reduction is the amount of plasticizer migration). The results are shown in Table 3. It can be seen from Table 3 that the migration amount of the plasticizer-plasticized PCV film of Example 1 is twice as low as that of the plasticizer-plasticized PVC films of Comparative Examples 1 and 2. The above fully reflects the advantages of the hyperbranched structure, and its migration resistance is better. This is because hyperbranched structure plasticizers have a higher molecular weight, which means they are less soluble in PVC materials and less compatible with PVC. This poor compatibility makes it more difficult for hyperbranched plasticizers to migrate out of PVC materials. At the same time, hyperbranched plasticizers usually have the ability to form chemical bonds with PVC. The formation of this chemical bond allows the plasticizer to be more firmly fixed in the PVC material, reducing the possibility of its migration. Spatial barrier effect: The molecular structure of hyperbranched plasticizers is relatively complex and usually has branches or other special structures. This structure can form a certain spatial barrier effect between molecules. This spatial barrier effect can effectively limit the migration of plasticizers and improve the anti-migration performance of PVC products.

Table 3: Migration test results table

First of all, the hyperbranched plasticizer synthesized in the embodiments of this application has the characteristics of complex molecular structure, good solubility and diffusibility, and good thermal stability, which makes it perform better than linear plasticizers in terms of plasticizing properties of PVC products. Secondly, the characteristics of hyperbranched plasticizers such as their more complex molecular structure, less impact on the mobility of the main chain, and better plasticization effect enable them to reduce the interaction force of PVC chains and improve the reactivity of PVC molecular chains. , thereby reducing the glass transition temperature of PVC products. Finally, compared with linear plasticizers, hyperbranched plasticizers have higher molecular weight, chemical bond formation ability and steric barrier effect. These characteristics make them have better anti-migration properties in PVC products.

In summary, the present invention provides a method for producing a hyperbranched succinic acid plasticizer. The plasticizer is solvent-free and can avoid cumbersome post-processing steps. On the basis of renewable raw material sources, it is easier to Achieve industrialization, and at the same time prove its good biocompatibility through standard tests, making it more widely used and safe, and it has good plasticizing effect. The hyperbranched succinic acid plasticizer synthesized in the present invention can greatly improve the mechanical properties and migration resistance of PVC materials. Therefore, the hyperbranched succinic acid plasticizer of the present invention has broad application prospects and has a positive impact on the environment and human health.

The above descriptions are only examples of the present application and are not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included in the protection scope of this application.

Claims (10)

1. A preparation method of hyperbranched succinate bio-based plasticizer, characterized in that: the preparation method includes the following steps: (1) Carry out melt polymerization of glycerin and succinic acid under the action of tin catalyst; the feeding ratio of glycerin and succinic acid is calculated based on the molar ratio of hydroxyl and carboxyl groups contained in each: [-OH]:[-COOH] =1.7-2.3; (2) The product obtained by melt polymerization is then subjected to high-temperature vacuum treatment to remove small molecular monomers and by-product water. The temperature of the high-temperature vacuum treatment is the same as the melt polymerization reaction temperature in step (1) to obtain hyperbranched succinate. Bio-based plasticizer. 2. The preparation method as claimed in claim 1, characterized in that: in step (1), the feeding ratio of glycerol and succinic acid is calculated as: [-OH]:[-COOH] according to the molar ratio of hydroxyl and carboxyl groups contained in each. =1.7. 3. The preparation method according to claim 1, characterized in that: the tin catalyst is dibutyltin oxide, and the added amount is 0.10wt%-0.20wt% of the total mass of glycerin and succinic acid. 4. The preparation method according to claim 1, characterized in that: in step (1), the melt polymerization temperature is 150°C-180°C; the reaction time is 8-20h. 5. The preparation method according to claim 1, characterized in that in step (1), the high temperature vacuum treatment conditions are: the temperature is 150°C-180°C, and the treatment time is 15min-45min. 6. Application of a hyperbranched succinate bio-based plasticizer prepared according to the preparation method of any one of claims 1 to 5 in plasticized PVC. 7. Application as claimed in claim 6, characterized in that: the application specifically includes: dissolving the hyperbranched succinate bio-based plasticizer and polyvinyl chloride powder in a solvent, stirring thoroughly and then leaving it alone. Until the solution is clear and has no obvious bubbles, the resulting solution is titrated on a glass plate through the solvent evaporation method to form a film, and finally the film is peeled off to obtain a PVC film. 8. The application according to claim 7, characterized in that: the mass ratio of the hyperbranched succinate bio-based plasticizer to polyvinyl chloride is 0.05-0.15. 9. The application according to claim 7, wherein the solvent is tetrahydrofuran, ethanol or N,N-dimethylformamide. 10. The application as claimed in claim 7, characterized in that the solvent evaporation conditions are: drying in a blast oven at 45°C-80°C for 1-3 hours.