Modified cardanol ester, multi-arm cardanol ester, preparation of modified cardanol ester and multi-arm cardanol ester, and application of multi-arm cardanol ester as plasticizer

Abstract

The invention discloses modified cardanol ester, multi-arm cardanol ester, preparation of the modified cardanol ester and the multi-arm cardanol ester, and application of the multi-arm cardanol ester as a plasticizer. The structure of the modified cardanol ester is as shown in a formula (I), or as shown in a formula (II), or a mixture of compounds as shown in a formula (III) and a formula (IV). The structure of the multi-arm cardanol ester is shown as a formula (V) or (VI). The invention provides application of the multi-arm cardanol ester as a plasticizer, especially a PLA (polylactic acid) plasticizer. The prepared multi-arm cardanol ester can effectively improve the migration resistance of a plasticizer in plastic, and the problem that the plasticizer is easy to separate out in the actual processing process is effectively solved. # imgabs0 # imgabs1 #

Description

Technical Field

[0001] The present invention relates to the field of processing aids for polymer materials, and particularly to a modified cashew phenol ester, a multi-arm cashew phenol ester, a preparation method thereof, and an application of the multi-arm cashew phenol ester as a plasticizer. Background Art

[0002] Cashew phenol is a compound refined from natural cashew nut shell liquid by advanced technology. It has antibacterial properties and is thus used as an additive in many formulations such as surfactants. Current research has shown that reacting cashew phenol with acetic anhydride can prepare a cashew phenol acetate plasticizer; epoxidizing cashew phenol can prepare an epoxidized cashew phenol acetate plasticizer; reacting maleic anhydride with cashew phenol can prepare a cashew phenol carboxylate surfactant. Cashew phenol has multiple advantages such as biodegradability, strong biological activity, and renewability, and is a natural compound with important application value and development prospects.

[0003] In the field of plastic processing aids, cashew phenol has been widely used due to the presence of a rigid benzene ring and flexible and hydrophobic long side chains in its structure. However, due to the lack of an ester group in its structure, its compatibility with plastics is poor. Although existing cashew phenol ester plasticizers have improved compatibility in plastics, their easy migration characteristics still limit their applications. Traditional petroleum-based plasticizers such as dioctyl phthalate (DOP) and dioctyl terephthalate (DOTP) contain benzene rings, ester bonds, and long alkyl chains, have relatively high compatibility with plastics, good plasticizing effects, and low migration rates, so there are few bio-based substitutes with comparable performance. Currently, most work is to improve the migration resistance of plasticizers by increasing the molecular weight of plasticizers and their compatibility with plastics, such as epoxidized soybean oil, tributyl citrate, triethyl citrate, and butyl acetyl citrate. However, existing plasticizers have problems such as unclear plasticizing effects when the addition amount is small, inability to be mixed and kneaded with plastic processing when the addition amount is large, and easy precipitation of the resulting products, thus affecting the properties of materials.

[0004] In the prior art, CN117229233A discloses a cashew phenol-based plasticizer. This method mainly adds the prepared epoxidized cashew phenol acetate and acetylated cashew phenol acetate plasticizers to PLA for plasticizing modification. The epoxidized cashew phenol acetate is prepared by stirring cashew phenol acetate with sulfuric acid at a certain temperature and dropping acetic acid and hydrogen peroxide for reaction; the cashew phenol acetate is prepared by stirring cashew phenol, acetic anhydride, and zinc perchlorate hexahydrate at room temperature and washing after the reaction is completed. Therefore, there is no relevant report on improving the migration resistance performance of cashew phenol ester plasticizers. Summary of the Invention

[0005] Based on the above, the technical problem to be solved by the present invention is to overcome the defects of the above-mentioned prior art, and provide a modified cashew phenol ester and its preparation method, a multi-arm cashew phenol ester and its preparation method, the application of the multi-arm cashew phenol ester as a plasticizer, and a PLA plasticized product. The multi-arm cashew phenol ester has a multi-arm structure while increasing the molecular weight of the plasticizer, which can not only improve the compatibility with PLA, but also effectively reduce the migration rate of the plasticizer.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a modified cashew phenol ester, whose structure is shown in formula (I), or shown in formula (II), or a mixture of compounds shown in formula (III) and (IV):

[0008]

[0009] Wherein n = 0, 2, 4 and / or 6.

[0010] In the second aspect, the present invention provides a preparation method of the modified cashew phenol ester described in the first aspect, including the following steps: adding cashew phenol and cyclic anhydride into a reaction vessel, the cyclic anhydride being succinic anhydride, maleic anhydride or itaconic anhydride, starting stirring, adding a catalyst into the reaction vessel after stirring evenly at room temperature, and reacting at room temperature to 150 °C for at least 1 hour to obtain the modified cashew phenol ester. The reaction equation is as follows:

[0011]

[0012]

[0013] Wherein n = 0, 2, 4 and / or 6.

[0014] Preferably, the catalyst is at least one of p-toluenesulfonic acid and N,N'-dicyclohexylcarbodiimide.

[0015] Preferably, the mass ratio of cashew phenol, cyclic anhydride and catalyst is (300 - 310):(110 - 130):(40 - 70).

[0016] Preferably, the reaction is carried out for more than 24 hours at room temperature or for 1 - 4 hours by heating to 80 - 150 °C.

[0017] In the third aspect, the present invention provides a multi-arm cashew phenol ester, whose structure is shown in formula (V) or (VI):

[0018]

[0019]

[0020] Among them, R1 is C 15 H 31-n , n = 0, 2, 4 and / or 6; each R2 is -(CH2)2- or -CH=CH-, or each R2 independently represents where * represents that this end group is connected to the phenoxycarbonyl group.

[0021] Fourthly, the present invention provides a preparation method of the multi-armed cardanol ester described in the third aspect, comprising the following steps:

[0022] (2) Add the modified cardanol ester described in the first aspect, the multi-functional group-containing compound, and the tertiary amine catalyst into a reaction vessel. After starting stirring and mixing evenly, heat up to 150-180 °C and react for 3-5 hours to obtain the multi-armed cardanol ester; the multi-functional group-containing compound is one of triglycidyl isocyanurate (TGIC) shown in formula (VII) and epoxidized soybean oil (ESO) shown in formula (VIII);

[0023]

[0024] Preferably, in step (2), the tertiary amine catalyst is at least one of 2-methylimidazole, 2-ethylimidazole, N,N-dimethylaniline, dodecyldimethylethylamine, and triphenylethylphosphonium bromide.

[0025] Preferably, in step (2), the mass ratio of the modified cardanol ester, the multi-functional group-containing compound, and the tertiary amine catalyst is (320-380):(100-150):(1-5).

[0026] Fifthly, the present invention provides the application of the multi-armed cardanol ester described in the third aspect as a plasticizer.

[0027] Preferably, the plasticizer is a PLA plasticizer.

[0028] Sixthly, the present invention provides a PLA plasticized product, which is made from raw materials of the following components:

[0029] PLA: 100 parts;

[0030] Plasticizer: 10-30 parts;

[0031] The plasticizer is the multi-armed cardanol ester described in the third aspect.

[0032] The preparation method of the PLA plasticized product includes the following steps:

[0033] Weigh each raw material by weight parts, melt and knead PLA and the plasticizer, and take out and let it cool naturally to obtain the PLA plasticized product.

[0034] Preferably, the melt mixing is carried out in a Haake torque rheometer. The temperature for melt mixing in the Haake torque rheometer is set at 150 - 180 °C, the mixing time is 5 - 20 minutes, and the rotor speed is 30 - 90 revolutions per minute.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention uses cyclic anhydride as a bridge to introduce ester bonds and more reactive groups into cardanol. On the one hand, the presence of ester bonds can improve the compatibility between the plasticizer and the plastic; on the other hand, the reactive groups can react with compounds containing polyfunctional groups to form multi - armed cardanol esters; the long side chain contained in cardanol itself can also endow the material with flexibility and hydrophobicity; in addition, the multi - armed structure also increases the molecular weight of the plasticizer, effectively reducing the migration rate of the plasticizer while plasticizing the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the infrared absorption spectrum of cardanol used in the present invention;

[0038] Figure 2 is the infrared absorption spectrum of the modified cardanol ester LS prepared in the present invention;

[0039] Figure 3 is the infrared absorption spectrum of the modified cardanol ester LM prepared in the present invention;

[0040] Figure 4 is the 1 HNMR spectrum of the modified cardanol esters (LS, LM) prepared in the present invention;

[0041] Figure 5 is the 1 HNMR spectrum of the multi - armed cardanol esters (LST, LSE) prepared in the present invention;

[0042] Figure 6 is the 1 HNMR spectrum of the modified cardanol ester LM and the multi - armed cardanol ester LMT prepared in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] The technical solutions of the present invention will be further described below through specific examples, but the protection scope of the present invention is not limited thereto.

[0044] In the examples of the present invention, those not specified under specific conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through conventional technical means or purchased commercially.

[0045] Cardanol, triphenylethylphosphonium bromide, 2-ethylimidazole and triglycidyl isocyanurate (TGIC) were provided by Jiangsu Alliance Chemical Co., Ltd. Epoxidized soybean oil, N,N'-dicyclohexylcarbodiimide, maleic anhydride and p-toluenesulfonic acid were all purchased from Macklin Reagent Co., Ltd. Succinic anhydride was provided by Kaiyuan Pharmaceutical Co., Ltd. The PLA used was a PLA product with the trade name REVODE101, provided by Zhejiang Hisun Biomaterials Co., Ltd.

[0046] The parts mentioned in the embodiments of the present invention are all parts by mass.

[0047] Example 1

[0048] A: According to the parts by mass ratio, 300 parts of cardanol (whose infrared absorption spectrum is as Figure 1 shown, 1 HNMR spectrum is as Figure 4 shown), 110 parts of succinic anhydride were added to the reaction vessel, stirring was started, and stirred at room temperature for 5 minutes, then 10 parts of p-toluenesulfonic acid and 40 parts of N,N'-dicyclohexylcarbodiimide were added to the reaction vessel, and reacted at room temperature for 24 hours to obtain the modified cardanol ester (LS) shown in Formula II, whose infrared absorption spectrum is as Figure 2 shown, 1 HNMR spectrum is as Figure 4 shown;

[0049] B: 320 parts of modified cardanol ester (LS), 100 parts of triglycidyl isocyanurate, and 4 parts of triphenylethylphosphonium bromide were added to the reaction vessel equipped with a condensation reflux device. After starting stirring and mixing evenly, the temperature was raised to 170 °C and reacted for 4 hours to obtain the multi-armed cardanol ester (LST), whose 1 HNMR spectrum is as Figure 5 shown.

[0050] C: 100 parts of PLA and 15 parts of multi-armed cardanol ester (LST) were kneaded with a Haake torque rheometer at 160 °C and 60 rpm for 10 minutes to obtain a PLA plasticized product.

[0051] Example 2

[0052] A: According to the parts by mass ratio, 310 parts of cardanol and 120 parts of maleic anhydride were added to the reaction vessel, stirring was started, and stirred at room temperature for 5 minutes, then 50 parts of N,N'-dicyclohexylcarbodiimide were added to the reaction vessel, and reacted at 120 °C for 2 hours to obtain the modified cardanol ester (LM) shown in Formula I, whose infrared absorption spectrum is as Figure 3 shown, 1 HNMR spectrum is as Figure 4 and Figure 6 shown;

[0053] B: Add 350 parts of modified cardanol ester (LM), 110 parts of triglycidyl isocyanurate, and 3 parts of 2-ethylimidazole into a reaction vessel equipped with a condensation reflux device. After starting stirring and mixing evenly, heat up to 160 °C and react for 5 hours to obtain multi-armed cardanol ester (LMT), whose 1 HNMR spectrum is as Figure 6 shown.

[0054] C: Knead 100 parts of PLA and 15 parts of multi-armed cardanol ester (LMT) with a Haake torque rheometer at 160 °C and 60 rpm for 10 minutes to obtain a PLA plasticized product.

[0055] Example 3

[0056] A: According to the mass ratio, add 350 parts of cardanol and 130 parts of succinic anhydride into a reaction vessel. Start stirring and stir at room temperature for 5 minutes. Then add 10 parts of p-toluenesulfonic acid and 40 parts of N,N'-dicyclohexylcarbodiimide into the reaction vessel and react at room temperature for more than 24 hours to obtain modified cardanol ester (LS);

[0057] B: Add 320 parts of modified cardanol ester, 150 parts of epoxidized soybean oil, and 5 parts of triphenylethylphosphonium bromide into a reaction vessel equipped with a condensation reflux device. After starting stirring and mixing evenly, heat up to 160 °C and react for 3 hours to obtain multi-armed cardanol ester (LSE), whose 1 HNMR spectrum is as Figure 5 shown.

[0058] C: Knead 100 parts of PLA and 15 parts of multi-armed cardanol ester (LSE) with a Haake torque rheometer at 160 °C and 60 rpm for 10 minutes to obtain a PLA plasticized product.

[0059] Comparative Example 1

[0060] Knead 100 parts of PLA and 15 parts of tributyl acetylcitrate (plasticizer) with a Haake torque rheometer at 160 °C and 60 rpm for 10 minutes to obtain a PLA plasticized product.

[0061] Comparative Example 2

[0062] Knead 100 parts of PLA and 15 parts of epoxidized soybean oil (plasticizer) with a Haake torque rheometer at 160 °C and 60 rpm for 10 minutes to obtain a PLA plasticized product.

[0063] Comparative Example 3

[0064] Mix 100 parts of PLA and 15 parts of epoxidized cashew phenol acetate plasticizer (prepared according to the method disclosed in paragraphs 0035 - 0040 of the specification of CN 117229233 A) using a Haake torque rheometer at 160 °C and 60 rpm for 10 minutes to obtain a PLA plasticized product. Evaluation method:

[0065] Characterize and test the products prepared in each example and comparative example. The characterization and testing methods are as follows:

[0066] 1. Migration test:

[0067] According to ISO 177:1988, use a circular specimen with a thickness of 0.5 mm, and the contact material is absorbent cotton. Assemble the weighed specimen and absorbent cotton, cover it with two glass plates, press a 5 kg weight on it, place it in an oven at 70 °C, take it out after 24 h, weigh the mass change of the specimen and absorbent cotton. The blank control is PLA without plasticizer. The experimental results are shown in Table 1.

[0068] Table 1 Comparison of migration test results

[0069] Blank Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Mobility / % 0 0.22 0.23 0.25 0.85 0.35 0.54

[0070] According to the results in Table 1, the migration rates of Examples 1 - 3 are significantly lower than those of Comparative Example 1 and Comparative Example 3, slightly lower than that of Comparative Example 2. It can be obtained that the migration rate of the bio - based multi - arm plasticizer prepared by the present invention is lower than that of the commonly used plasticizers for PLA.

[0071] 2. Mechanical property test:

[0072] On a universal material testing machine controlled by Jiangsu Qiantong (QT - 6201S), conduct mechanical property tests on the spline according to GB / T 1040.1 - 2006 to obtain the elongation at break (EB, %) and tensile strength (TS, MPa) of the sample. Among them, the spline is a 5A - type spline, the fixture spacing is set to 30 mm, the tensile speed is 50 mm / min, 3 - 5 samples are prepared for each group for testing, take the average value, calculate the error, and the blank control is PLA without plasticizer. The experimental results are shown in Table 2.

[0073] Table 2 Comparison of mechanical property test results

[0074] Tensile strength (MPa) Elongation at break (%) Blank 69.7 9 Example 1 32.6 223 Example 2 31.4 234 Example 3 32.0 210 Comparative Example 1 27.4 267 Comparative Example 2 31.9 113 Comparative Example 3 28.6 297

[0075] According to the results in Table 2, compared with the blank control, Examples 1 - 3 all have obvious plasticizing effects. Their plasticizing effects are similar to those of Comparative Example 1, better than those of Comparative Example 2, and slightly lower than those of Comparative Example 3.

[0076] 3. Hardness & density test:

[0077] On the HLX-AC type hardness tester, the hardness of the test specimen was measured according to GB / T 2411-2008. The hardness tester was of type A. Five hardness values were measured on the same specimen, and their average value was calculated. On the FK-120DT type electronic density meter, the density of the test specimen was measured by the immersion method according to GB / T1033.1-2008. Five density values were measured on the same specimen, and their average value was calculated. The blank control was PLA without plasticizer. The experimental results are shown in Table 3.

[0078] Table 3 Comparison of Hardness & Density Test Results

[0079] Hardness (A / 1) <![CDATA[Density (g / cm 3 )]]> Blank 98 1.23 Example 1 96 1.21 Example 2 96 1.22 Example 3 95 1.20 Comparative Example 1 97 1.25 Comparative Example 2 94 1.18 Comparative Example 3 96 1.20

[0080] According to the results in Table 3, the hardness and density of Examples 1 to 3 were lower than those of the blank control and were similar to those of Comparative Example 3.

[0081] 4. Fourier Transform Infrared Spectroscopy (FT-IR) Analysis:

[0082] Fourier Transform Infrared Spectroscopy (FT-IR) analysis was performed using a PerkinElmer 782 infrared spectrometer with a scanning frequency of 32 and a scanning range of 400 - 4000 cm -1 , and a resolution of 4 cm -1 .

[0083] Figure 1 、 Figure 2 and Figure 3 at 3008 - 3009 cm -1 are the characteristic absorption peaks of unsaturated olefins, and at 2924 - 2925 cm -1 and 2853 - 2854 cm -1 are the characteristic absorption peaks of methyl and methylene groups. By comparing Figure 1 and Figure 2 , it can be seen that the new absorption peaks of the modified cashew phenol intermediate LS at 1761 cm -1 and 1713 cm -1 are the characteristic peaks of the carbonyl groups in carboxyl and ester bonds respectively. At the same time, the characteristic peak of the hydroxyl group at 3354 cm -1 disappears, indicating that the phenolic hydroxyl group of cashew phenol reacts completely with cyclic anhydride and the target product is successfully obtained; by comparing Figure 1 and Figure 3 , it can be seen that the new absorption peaks of the modified cashew phenol intermediate LM at 1750 cm -1 and 1688 cm -1 are the characteristic peaks of the carbonyl groups in carboxyl and ester bonds respectively, and the target product is successfully obtained.

[0084] 5. Nuclear Magnetic Resonance Hydrogen Spectrum ( 1 HNMR) Analysis:

[0085] 1H nuclear magnetic resonance ( 1 HNMR) spectra were recorded on a Bruker Ascend TM 600 MHz instrument operating at a magnetic field frequency of 600 MHz, using deuterated chloroform as the solvent.

[0086] From Figure 4 it can be seen the structural changes of LS and LM formed after the reaction of cardanol with cyclic anhydride. A new methylene proton peak appears at 2.92 ppm for LS, and new proton peaks located at the double bond appear at 6.40 ppm and 6.60 ppm for LM. From Figure 5 and Figure 6 it is known that for multi-arm cardanol ester plasticizers (LST, LSE, and LMT), proton peaks on the carbon atoms connected to the generated hydroxyl groups after epoxy ring opening all appear at 4.00 - 4.50 ppm.

[0087] The technical scope of the present invention is not limited only to the content described above. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of the present invention, and these deformations and modifications should all fall within the scope of the present invention.

Claims

1. A modified cashew phenol ester, characterized in that: The structure of the modified cardanol ester is shown in formula (I), or formula (II), or a mixture of compounds shown in formula (III) and (IV): where n = 0, 2, 4 and / or 6.

2. A preparation method of the modified cardanol ester as described in claim 1, characterized in that: The preparation method includes the following steps: adding cardanol and cyclic anhydride into a reaction vessel, where the cyclic anhydride is succinic anhydride, maleic anhydride or itaconic anhydride, starting stirring, after stirring evenly at room temperature, adding a catalyst into the reaction vessel, reacting at room temperature to 150 °C for at least 1 hour to obtain the modified cardanol ester, and the reaction equation is as follows: where n = 0, 2, 4 and / or 6.

3. The preparation method according to claim 2, characterized in that: The catalyst is at least one of p-toluenesulfonic acid and N,N'-dicyclohexylcarbodiimide.

4. The preparation method according to claim 2 or 3, characterized in that: The reaction is carried out by reacting at room temperature for more than 24 hours or heating to 80 - 150 °C and reacting for 1 - 4 hours.

5. A multi-arm cardanol ester, characterized in that: The structure of the multi-arm cardanol ester is shown in formula (V) or (VI): Among them, R1 is C 15 H 31-n , n = 0, 2, 4 and / or 6; each R2 is -(CH2)2- or -CH=CH-, or each R2 independently represents where * represents that this end group is connected to the phenoxycarbonyl group.

6. A preparation method of the multi-arm cashew phenol ester as described in claim 5, characterized in that: The preparation method includes the following steps: (2) Adding the modified cardanol ester, multi-functional group-containing compound, and tertiary amine catalyst described in claim 1 into a reaction vessel, starting stirring and mixing evenly, then heating to 150 - 180 °C and reacting for 3 - 5 hours to obtain the multi-arm cardanol ester; the multi-functional group-containing compound is one of triglycidyl isocyanurate shown in formula (VII) and epoxidized soybean oil shown in formula (VIII); 7. The preparation method according to claim 6, characterized in that: In step (2), the tertiary amine catalyst is at least one of 2-methylimidazole, 2-ethylimidazole, N,N-dimethylaniline, dodecyldimethylethylamine, and triphenylethylphosphonium bromide.

8. The application of the multi-arm cardanol ester as described in claim 5 as a plasticizer.

9. The application according to claim 8, wherein: The plasticizer is a PLA plasticizer.

10. A PLA plasticized product, characterized in that: The PLA plasticized product is made from raw materials of the following components: PLA: 100 parts; Plasticizer: 10 - 30 parts; The plasticizer is the multi-arm cardanol ester as described in claim 5.

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