A preparation method of PVC processing aid

Abstract

The present application relates to the technical field of plastic processing aids, and specifically discloses a method for preparing a PVC processing aid. A method for preparing a PVC processing aid, based on elaiophyllic acid, introduces a rigid benzene ring structure through esterification with benzyl alcohol, introduces a ketal and an ester structure through reaction with ethyl levulinate, then reacts with palmitoleic acid to introduce a double bond, and forms an epoxy structure through cyclization with m-chlorobenzene peroxyformic acid, and finally prepares a PVC processing aid, and the prepared PVC processing aid has higher plasticity, lower volatility and lower mobility. In addition, the PVC processing aid of the present application uses biomass renewable resources as raw materials, is non-toxic and harmless, and is environmentally friendly.

Description

Technical Field

[0001] The present application relates to the technical field of plastic processing aids, and more specifically, to a method for preparing a PVC processing aid. Background Art

[0002] Polyvinyl chloride (PVC) is a material that is currently used in a huge amount in the field of polymer materials and has a wide range of applications. PVC is used in floors, cables, packaging, pipes, and medical fields. The pure resin of PVC is easy to decompose during processing, has poor fluidity, low impact strength, and poor weather resistance. Therefore, various auxiliary materials need to be added during the processing to improve its performance. Such as: lubricants, heat stabilizers, impact modifiers, processing aids, etc. Among them, since PVC is a polar polymer, it has strong rigidity at room temperature and exhibits the characteristics of brittle materials. At the same time, its high-temperature processing is often accompanied by degradation, which limits its wider application. Therefore, in order to improve the determination of insufficient toughness of PVC, it is very necessary to plasticize it.

[0003] However, the current mainstream conventional plasticizers, phthalates (accounting for about 80% of the total market share), not only cause damage to the peripheral nervous system, have embryotoxicity and teratogenicity, but also interfere with the secretion of hormones in the body, causing carcinogenesis and promoting cancer cell proliferation. With the improvement of environmental awareness in countries around the world, Europe, the United States, Japan and other countries have issued restrictions or even directly banned them. To this end, researchers have actively developed a variety of bio-based plasticizer alternatives. Bio-based plasticizers are a new type of plasticizers that are non-toxic, harmless and environmentally friendly, prepared from renewable biomass resources through a series of different synthetic methods such as esterification, such as epoxy fatty acid methyl esters, epoxy soybean oil, epoxy cottonseed oil, cardanol crotonate, citrate, polyester plasticizers, etc., which are intended to replace traditional petroleum-based plasticizers to reduce harm to the environment and humans. Because it has good renewable, low-toxic and environmentally friendly characteristics. Summary of the invention

[0004] In order to further enrich the selectivity of bio-based plasticizers, the present application provides a method for preparing a PVC processing aid.

[0005] In the first aspect, the present application provides a method for preparing a PVC processing aid, using the following technical solution:

[0006] A method for preparing a PVC processing aid comprises the following steps: S1, mixing elaioic acid, benzyl alcohol, p-toluenesulfonic acid and toluene in proportion, reacting at 110-120°C for 10-12h under a nitrogen atmosphere, cooling to room temperature, washing with a sodium bicarbonate solution until neutral, and removing the solvent to obtain a product a; S2, mixing the product a, ethyl levulinate, p-toluenesulfonic acid and toluene in proportion, reacting at 80-90°C for 40-60min under a nitrogen atmosphere, and then heating to 11 0-120℃, react for 40-60min, remove excess ethyl levulinate to obtain product b solution; S3, add palmitic acid and p-toluenesulfonic acid to product b solution, heat to 160-170℃, react for 2-3h, wash with sodium bicarbonate solution until neutral, remove the solvent to obtain product c; S4, dissolve product c in dichloromethane, add m-chlorobenzene peroxyformic acid, react at room temperature for 30-40min, wash twice with potassium carbonate solution, remove the solvent to obtain PVC processing aid.

[0007] By adopting the above technical scheme, based on elaiophyllic acid, a rigid benzene ring structure is introduced through esterification with benzyl alcohol, and then a ketal and ester structure are introduced through reaction with ethyl levulinate, and then a double bond is introduced through esterification reaction with palmitoleic acid, and an epoxy structure is formed through cyclization with m-chlorobenzene peroxyformic acid, and finally a PVC processing aid is prepared, which uses biomass renewable resources as raw materials, is non-toxic, harmless, and environmentally friendly.

[0008] Preferably, the molar ratio of elaeuric acid, benzyl alcohol, p-toluenesulfonic acid and toluene in S1 is 1:(1-1.2):(0.02-0.03):(1-1.2).

[0009] Preferably, the molar ratio of product a, ethyl levulinate, p-toluenesulfonic acid and toluene in S2 is 1:(4-5):(0.03-0.05):(1.6-1.8).

[0010] Preferably, the molar ratio of the product a in S2 and the palmitoleic acid to p-toluenesulfonic acid in S3 is 1:(0.9-1.1):(0.001-0.002).

[0011] Preferably, the molar volume ratio of the product c, m-chlorobenzene peroxyformic acid, and dichloromethane in S4 is 1 mol: (1.2-1.4) mol: (80-100) mL.

[0012] Preferably, the toluene, ethyl levulinate and dichloromethane are removed by rotary evaporation under reduced pressure.

[0013] In a second aspect, the present application provides a PVC processing aid, which is prepared using the above method.

[0014] The prepared PVC processing aid has a longer side chain, a larger molecular weight and relatively abundant functional groups such as ketal, epoxy, and ester groups, which can produce a stronger interaction force with the PVC molecular chain to obtain a better plastic effect, and at the same time has a lower volatility and mobility.

[0015] Preferably, the amount of the PVC processing aid added in PVC processing is 5-30% by mass.

[0016] Preferably, when the PVC processing aid is used in PVC processing, a heat stabilizer is added, and the amount of the heat stabilizer added is 1.5-2.5% by mass.

[0017] The PVC processing aid has a plasticizing effect.

[0018] In summary, this application has the following beneficial effects:

[0019] 1. The present application is based on elaiophyllic acid, and introduces a rigid benzene ring structure through esterification with benzyl alcohol, and then introduces a ketal and ester structure through reaction with ethyl levulinate, and then introduces a double bond through esterification with palmitoleic acid, and forms an epoxy structure through cyclization with m-chlorobenzene peroxyformic acid, and finally prepares a PVC processing aid, which uses biomass renewable resources as raw materials, is non-toxic, harmless, and environmentally friendly.

[0020] 2. The PVC processing aid prepared by the preparation method of the present application has a longer side chain, a larger molecular weight and relatively abundant functional groups such as ketal, epoxy, and ester groups, which can produce a stronger interaction force with the PVC molecular chain to obtain a better plastic effect, and at the same time has a lower volatility and mobility.

[0021] 3. The PVC processing aid prepared by the preparation method of the present application has a high plastic effect, which is comparable to commercial terephthalate plasticizers. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 : Flow chart of the preparation method of PVC processing aid of the present application.

[0023] Figure 2 : Hydrogen spectrum of PVC processing aid in this application.

[0024] Figure 3 : SEM image of the cross-sectional morphology of the PVC-10 sample of the present application (the left corresponds to the pure PVC sample, and the right corresponds to the PVC-10 sample). DETAILED DESCRIPTION

[0025] The present application is further described in detail below in conjunction with embodiments.

[0026] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available.

[0027] Example

[0028] Example 1

[0029] A method for preparing a PVC processing aid (such as Figure 1 ), including the following steps:

[0030] S1, 1 mol of elaioacic acid, 1 mol of benzyl alcohol, 0.02 mol of p-toluenesulfonic acid and 1 mol of toluene are mixed, reacted at 110°C for 10 h under a nitrogen atmosphere, cooled to room temperature, washed with a 5% sodium bicarbonate aqueous solution until neutral, and evaporated under reduced pressure to remove solvents such as toluene (toluene is used as a water-carrying solvent here), to obtain product a;

[0031] S2, 1 mol of product a, 4 mol of ethyl levulinate, 0.03 mol of p-toluenesulfonic acid and 1.6 mol of toluene are mixed, reacted at 80° C. for 40 min under a nitrogen atmosphere, then heated to 110° C. and reacted for 40 min, and the excess ethyl levulinate is removed by vacuum rotary evaporation to obtain a product b solution;

[0032] S3, adding 0.9 mol of palmitic acid and 0.001 mol of p-toluenesulfonic acid to the product b solution, heating to 160°C for 2 h, washing with 5% sodium bicarbonate solution until neutral, and removing toluene and other solvents (toluene is used as a water-carrying solvent here) by vacuum rotary evaporation to obtain product c;

[0033] S4, dissolving 1 mol of product c in 80 mL of dichloromethane, adding 1.2 mol of m-chlorobenzene peroxyformic acid, reacting at room temperature for 30 min, washing with potassium carbonate solution twice, removing the dichloromethane solvent by vacuum rotary evaporation, and obtaining product d, i.e., PVC processing aid.

[0034] Using H NMR spectroscopy ( 1 HNMR) was used to test the prepared PVC processing aid, and the solvent used was deuterated chloroform. Figure 2 As shown, 1HNMR (400MHz: CDCl3, δ, ppm, J in Hz)) δ7.32-7.33 (t, J = 4.7Hz, 5H), 5.15 (s, 2H), 4.13 (q, J = 5.2Hz, 2H), 4.01 (q, J = 8.3Hz, 2H), 3.72 (m, J = 6.5Hz, 2H), 2.35 (T, J = 4.5Hz, 2H), 2.34 (m, J = 9.1Hz, 2H), 2.32 (m, J = 8.1Hz, 4H), 1.92 (T, J = 6.5Hz, 2H), 1.66-1.60 (m, J = 6.3Hz, 6H), 1.43-1.38 (m, J = 10.1Hz, 10H), 1.33-1.25 (m, J = 12.5Hz, 31H), 1.07 (T, J = 7.4Hz, 3H), 0.08 (T, J = 6.9Hz, 3H)

[0035] Example 2

[0036] A method for preparing a PVC processing aid (such as Figure 1 ), including the following steps:

[0037] S1, 1 mol of elaioacic acid, 1.1 mol of benzyl alcohol, 0.03 mol of p-toluenesulfonic acid and 1.1 mol of toluene were mixed, reacted at 115°C for 11 hours under a nitrogen atmosphere, cooled to room temperature, washed with a 5% sodium bicarbonate aqueous solution until neutral, and evaporated under reduced pressure to remove solvents such as toluene (toluene is used as a water-carrying solvent here), to obtain product a;

[0038] S2, 1 mol of product a, 4.5 mol of ethyl levulinate, 0.04 mol of p-toluenesulfonic acid and 1.7 mol of toluene are mixed, reacted at 85° C. for 50 min under a nitrogen atmosphere, then heated to 115° C. and reacted for 50 min, and the excess ethyl levulinate is removed by vacuum rotary evaporation to obtain a product b solution;

[0039] S3, adding 1.0 mol of palmitic acid and 0.002 mol of p-toluenesulfonic acid to the product b solution, heating to 165°C for reaction for 2.5 h, washing with 5% sodium bicarbonate solution until neutral, and removing toluene and other solvents (toluene is used as a water-carrying solvent here) by vacuum rotary evaporation to obtain product c;

[0040] S4, dissolving 1 mol of product c in 90 mL of dichloromethane, adding 1.3 mol of m-chlorobenzene peroxyformic acid, reacting at room temperature for 35 min, washing with potassium carbonate solution twice, removing the dichloromethane solvent by vacuum rotary evaporation, and obtaining product d, i.e., PVC processing aid.

[0041] Example 3

[0042] A method for preparing a PVC processing aid (such as Figure 1 ), including the following steps:

[0043] S1, 1 mol of elaioic acid, 1.2 mol of benzyl alcohol, 0.03 mol of p-toluenesulfonic acid and 1.2 mol of toluene were mixed, reacted at 120°C for 12 h under a nitrogen atmosphere, cooled to room temperature, washed with a 5% sodium bicarbonate aqueous solution until neutral, and evaporated under reduced pressure to remove solvents such as toluene (toluene is used as a water-carrying solvent here), to obtain product a;

[0044] S2, 1 mol of product a, 5 mol of ethyl levulinate, 0.05 mol of p-toluenesulfonic acid and 1.8 mol of toluene are mixed, reacted at 90° C. for 60 min under a nitrogen atmosphere, then heated to 120° C. and reacted for 60 min, and the excess ethyl levulinate is removed by vacuum rotary evaporation to obtain a product b solution;

[0045] S3, adding 1.1 mol of palmitic acid and 0.002 mol of p-toluenesulfonic acid to the product b solution, heating to 170°C for reaction for 3 h, washing with 5% sodium bicarbonate solution until neutral, and removing toluene and other solvents (toluene is used as a water-carrying solvent here) by vacuum rotary evaporation to obtain product c;

[0046] S4, dissolving 1 mol of product c in 100 mL of dichloromethane, adding 1.4 mol of m-chlorobenzene peroxyformic acid, reacting at room temperature for 40 min, washing twice with potassium carbonate solution, removing the dichloromethane solvent by vacuum rotary evaporation, and obtaining product d, i.e., PVC processing aid.

[0047] Preparation process of PVC plasticized with PVC processing aid: polyvinyl chloride is vacuum dried at 80°C for 10 hours to remove moisture, and then melt-processed with PVC processing aid and 2% by mass of methyl tin heat stabilizer at 165°C for 3 minutes using a double-roll mill to obtain PVC samples plasticized with PVC processing aid, wherein the addition amounts of PVC processing aid are 5%, 10%, 15%, 20%, 25% and 30%, respectively. The prepared PVC samples are respectively recorded as PVC-5, PVC-10, PVC-15, PVC-20, PVC-25 and PVC-30. Among them, PVC-5 represents the PVC sample prepared when the addition amount of PVC processing aid is 5%; PVC-10 represents the PVC sample prepared when the addition amount of PVC processing aid is 10%; PVC-15 represents the PVC sample prepared when the addition amount of PVC processing aid is 15%; PVC-20 represents the PVC sample prepared when the addition amount of PVC processing aid is 20%; PVC-25 represents the PVC sample prepared when the addition amount of PVC processing aid is 25%; PVC-30 represents the PVC sample prepared when the addition amount of PVC processing aid is 30%.

[0048] Comparative Example

[0049] Comparative Example 1

[0050] DOTP (dioctyl terephthalate) was used instead of the PVC processing aid prepared in the present application to prepare a PVC sample plasticized by the PVC processing aid.

[0051] Comparative Example 2

[0052] Pure PVC samples were prepared using only PVC as raw material.

[0053] Performance testing

[0054] (1) Mechanical properties test: Each PVC sample was compression molded at 165°C to prepare notched impact specimens (V-notch, 100 mm × 10 mm × 5 mm) and dumbbell-type tensile test specimens (75 mm × 5 mm × 2 mm). An impact tester was used for impact testing, and a tensile machine was used for tensile performance testing at a tensile rate of 50 mm / min.

[0055] (2) Hardness test: The hardness of each PVC sample was tested using a Shore hardness tester. The test process was carried out in accordance with ISO868:2003 standard.

[0056] (3) Migration resistance and volatility resistance test: The migration resistance test and volatility resistance test methods are carried out in accordance with ISO177:1988 (E) test standard (using deionized water as solvent).

[0057] The results are shown in Table 1:

[0058] Table 1. PVC processing aid performance test results

[0059]

[0060] As can be seen from Table 1, the comprehensive plasticizing effect of the PVC processing aid prepared in the present application is stronger. Both the PVC processing aid and DOTP significantly improve the impact properties of PVC. The impact strength of the PVC sample and the amount of PVC processing aid added show a trend of first increasing and then decreasing. Compared with DOTP, the PVC processing aid has a better effect on improving the impact strength of PVC, indicating that the PVC processing aid has a good plasticizing effect on PVC resin. This may be due to the fact that the molecular structure of the side chain of the PVC processing aid is longer than that of the side chain of DOTP. At the same time, the acetyl, ketal, epoxy functional groups it has enable it to better interact with the PVC molecular chain, and can better produce a "cage effect" at a low addition amount (<20%), which slightly weakens the interaction between PVC molecules and obtains better plasticity, thereby showing that its impact strength is more significantly improved; the Shore hardness D of the PVC sample is lower than that of pure PVC, and shows a linear downward trend with the increase of the addition amount. Compared with DOTP, PVC processing aid has a lower Shore hardness, and its change pattern is consistent with the change pattern of mechanical properties test, which shows that the synthesized PVC processing aid has a plasticizing effect that is comparable to that of the commercial plasticizer DOTP; compared with DOTP, PVC processing aid has stronger anti-migration and anti-volatility. This may be due to the large relative molecular mass and rich functional groups of PVC processing aid. There are more polar functional groups such as acetyl, ketal, and epoxy functional groups, which have a strong interaction force with the PVC molecular chain, making it more stable and reducing volatility and migration.

[0061] (4) Thermal gravimetric test: The thermal stability of each PVC sample was tested using a thermal gravimetric analyzer. The test conditions were a nitrogen atmosphere, the mass of the PVC sample was 6 mg, and the temperature conditions were a heating rate of 10°C / min, a range of 25-500°C, and the temperature at which the thermal gravimetric loss was 5% was recorded.

[0062] The results show that the temperature at which the PVC sample with the participation of DOTP loses 5% of its thermogravimetric value is in the range of 199.1-201.5°C, and the temperature at which the PVC sample with the participation of the PVC processing aid of the present application loses 5% of its thermogravimetric value is in the range of 202.2-204.8°C, which indicates that the thermal stability of the PVC processing aid of the present application is stronger than that of DOTP. This may be because the PVC processing aid of the present application has a higher relative molecular mass and a rich functional group structure such as epoxy groups, which enhances the thermal stability of PVC and increases its thermal decomposition temperature.

[0063] (5) Use scanning electron microscopy to observe the cross-section of plasticized PVC samples. The microscopic morphology of PVC and PVC-10 samples is as follows: Figure 3 shown.

[0064] from Figure 3 It can be seen that pure PVC has a brittle fracture morphology, and the microscopic fracture morphology of the PVC-10 sample becomes rougher than that of pure PVC, with more fracture sites, indicating that PVC-10 has a good plasticizing effect and its flexibility has been improved; in addition, Figure 3 It can also be seen that there are no holes and agglomeration in PVC-10 due to the compatibility problem between PVC processing aids and PVC, indicating that the PVC processing aids can be well dispersed in the PVC matrix.

[0065] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, a person skilled in the art may make non-creative modifications to the present embodiment as needed, and such modifications shall be protected by the patent law as long as they are within the scope of protection claimed in the present application.

Claims

1. A method for preparing a PVC processing aid, characterized in that: The method comprises the following steps: S1, mixing elaioidal acid, benzyl alcohol, p-toluenesulfonic acid and toluene in proportion, reacting at 110-120° C. for 10-12 hours under a nitrogen atmosphere, cooling to room temperature, washing with sodium bicarbonate solution until neutral, and removing the solvent to obtain product a; the structure of product a is: ; S2, product a, ethyl levulinate, p-toluenesulfonic acid, and toluene are mixed in proportion, reacted at 80-90° C. for 40-60 min under a nitrogen atmosphere, then heated to 110-120° C., reacted for 40-60 min, and excess ethyl levulinate was removed to obtain a product b solution; the structure of product b in the product b solution is: ； S3, adding palmitic acid and p-toluenesulfonic acid to the product b solution, heating to 160-170°C for reaction for 2-3h, washing with sodium bicarbonate solution until neutral, removing the solvent, and obtaining product c; The structure of product c is: ; S4, dissolving product c in dichloromethane, adding m-chlorobenzene peroxyformic acid, reacting at room temperature for 30-40 minutes, washing with potassium carbonate solution twice, removing the solvent, and obtaining a PVC processing aid; the structure of the PVC processing aid is: .

2. The method for preparing a PVC processing aid according to claim 1, characterized in that: The molar ratio of elaiolic acid, benzyl alcohol, p-toluenesulfonic acid and toluene in S1 is 1:(1-1.2):(0.02-0.03):(1-1.2).

3. The method for preparing a PVC processing aid according to claim 2, characterized in that: The molar ratio of product a, ethyl levulinate, p-toluenesulfonic acid and toluene in S2 is 1:(4-5):(0.03-0.05):(1.6-1.8).

4. The method for preparing a PVC processing aid according to claim 3, characterized in that: The molar ratio of the product a in S2 and the palmitoleic acid to p-toluenesulfonic acid in S3 is 1:(0.9-1.1):(0.001-0.002).

5. The method for preparing a PVC processing aid according to claim 4, characterized in that: The molar volume ratio of the product c, m-chlorobenzene peroxyformic acid, and dichloromethane in S4 is 1 mol: (1.2-1.4) mol: (80-100) mL.

6. The method for preparing a PVC processing aid according to claim 5, characterized in that: The toluene, ethyl levulinate and dichloromethane are removed by rotary evaporation under reduced pressure.

7. A PVC processing aid, characterized in that: The PVC processing aid is prepared by the preparation method of any one of claims 1 to 6.

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