阅读说明：本技术 一种聚酯增塑剂的制备方法及其产品和应用 (Preparation method of polyester plasticizer, product and application thereof ) 是由 于跃 邓利 韩志跃 王芳 杨众 杨兴 于 2021-09-16 设计创作，主要内容包括：本发明公开一种聚酯增塑剂的制备方法及其产品和应用。包括以下步骤：在氮气氛围下,将二元醇与二元酸混合物进行酯化反应,得到预聚物；将脂肪酶加入到预聚物中进行缩聚反应,得到聚酯粗品；以聚酯粗品和聚二甲硅氧烷为原料,在催化剂作用下进行接枝反应,得到改性聚酯粗品；对得到的改性聚酯粗品进行分离纯化,得到聚酯增塑剂。本发明具有绿色环保,存在副反应少,溶剂消耗少,分散系数小,操作简单,分子量可控等优点。获得的聚酯增塑剂具有耐抽出、耐迁移、无毒的特点,能够显著提高NBR的力学性能和耐低温性能。(The invention discloses a preparation method of a polyester plasticizer, and a product and application thereof. The method comprises the following steps: carrying out esterification reaction on dihydric alcohol and a dibasic acid mixture in a nitrogen atmosphere to obtain a prepolymer; adding lipase into the prepolymer to carry out polycondensation reaction to obtain a polyester crude product; taking a crude polyester product and polydimethylsiloxane as raw materials, and carrying out grafting reaction under the action of a catalyst to obtain a crude modified polyester product; and separating and purifying the obtained crude modified polyester product to obtain the polyester plasticizer. The method has the advantages of environmental protection, less side reaction, less solvent consumption, small dispersion coefficient, simple operation, controllable molecular weight and the like. The obtained polyester plasticizer has the characteristics of extraction resistance, migration resistance and no toxicity, and can obviously improve the mechanical property and the low-temperature resistance of the NBR.)

1. The preparation method of the polyester plasticizer is characterized by comprising the following steps of:

(1) carrying out esterification reaction on dihydric alcohol and a dibasic acid mixture in a nitrogen atmosphere to obtain a prepolymer;

(2) adding lipase into the prepolymer to carry out polycondensation reaction to obtain a polyester crude product;

(3) taking the crude polyester product and polydimethylsiloxane as raw materials, and carrying out grafting reaction under the action of a catalyst to obtain a crude modified polyester product;

(4) and separating and purifying the crude modified polyester product to obtain the polyester plasticizer.

2. The process according to claim 1, wherein the diol of step (1) is two or more selected from the group consisting of 1, 3-propanediol, 1, 2-propanediol, butanediol, pentanediol, hexanediol, and octanediol; the dibasic acid is one or more of succinic acid, adipic acid, sebacic acid, fumaric acid and malic acid.

3. The method according to claim 1, wherein the molar ratio of the diol to the diacid in step (1) is 8:1 to 1: 1; the esterification reaction temperature is 100-180 ℃, and the time is 1-8 h.

4. The method according to claim 1, wherein the Lipase in step (2) is one of Novozym435, Novozym40086, porcine pancreatin, Candida rugosa, Lipozyme RM IM, Lipozyme TL IM and Lipase AS.

5. The preparation method according to claim 1, wherein the lipase is added in the step (2) in an amount of 1-10% of the mass of the prepolymer; the polycondensation reaction temperature is 50-80 ℃, the time is 12-48h, and the pressure is 200-500 Pa.

6. The method according to claim 1, wherein the molar ratio of the crude polyester and the polydimethylsiloxane in step (3) is 1: (0.1-0.3), wherein the dosage of the catalyst is 5 per mill of the total molar mass of the crude polyester and the polydimethylsiloxane; the catalyst is dibutyl tin dilaurate.

7. The method as claimed in claim 1, wherein the grafting reaction temperature in step (3) is 140 ℃ and 180 ℃ for 3-5 h.

8. A polyester plasticizer obtainable by the production process according to any one of claims 1 to 7.

9. The preparation method of the nitrile rubber is characterized by comprising the following steps: adding carbon black, zinc oxide, stearic acid, an accelerator TMTD, an accelerator CZ, a vulcanizing agent and the polyester plasticizer according to claim 8 into raw nitrile rubber, mixing and vulcanizing.

10. A nitrile rubber as obtained according to the preparation process of claim 9.

Technical Field

The invention belongs to the field of polyester plasticizers and rubber additives, and particularly relates to a preparation method of a polyester plasticizer, a product and application thereof.

Background

Nitrile-butadiene rubber (NBR) is a synthetic rubber widely used in the fields of automobiles, aviation, construction, and the like, and is an unsaturated polymer obtained by copolymerizing two monomers, namely butadiene and acrylonitrile. The NBR has better oil resistance, wear resistance and the like, but the existence of acrylonitrile with larger polarity leads to poorer cold resistance, but the reduction of the proportion of the acrylonitrile in the NBR leads to the reduction of the oil resistance, so that a proper polymer auxiliary agent needs to be found to improve the low temperature resistance of the NBR and widen the use temperature range of rubber products.

The plasticizer is a solvent-like additive, and can improve the processability of the material, the mechanical property, the cold resistance and the like of the material. The most commonly used plasticizer is mainly o-benzene plasticizer which has better plasticizing effect, but with the wider application, researches show that the plasticizer has potential toxicity and can interfere the endocrine system of the organism, so that many countries have already commendably banned the corresponding o-benzene plasticizer in the fields of food, medicine, children toys and the like which can be contacted with human bodies. At present, a substitute of the o-benzene plasticizer, namely a novel environment-friendly plasticizer, is researched at home and abroad.

The polyester plasticizer is a novel non-toxic environment-friendly plasticizer with the advantages of extraction resistance, migration resistance and volatilization resistance, but the scale of the domestic polyester plasticizer market is not formed at present, and the synthesis of the polyester plasticizer needs to be further researched. The common method for synthesizing polyester is a chemical method, strong acid or metal is used as a catalyst, the catalytic efficiency is high, the reaction is rapid, but the reaction temperature is high, so that a plurality of byproducts are generated, and the products are not easy to separate. With the establishment of enzyme-catalyzed reaction in nonaqueous phase, lipase becomes a research hotspot in the field of biochemical engineering, and the lipase also belongs to renewable energy sources and is applied to industrial production at present. Compared with the traditional chemical synthesis method, the enzyme catalysis method has high-efficiency selectivity, comprises corresponding selectivity and regioselectivity, can be used for reaction in various different media, belongs to a green renewable resource, is non-toxic and harmless, enables the reaction to be carried out under mild conditions, and is a novel environment-friendly green biocatalyst. However, only some commercial lipases and immobilized enzymes are currently used for the research on the synthesis of polyester, and the current polyester synthesis catalyzed by enzymes has a gap from practical application, on one hand, the reaction cost is high, the efficiency is low, the reaction time is usually from hours to days, the catalyst dosage is large, and some of the catalysts are even equivalent to the monomer quality; on the other hand, many of the products have low molecular weights and are difficult to be used as polymer materials independently.

The halolon adopts tetrabutyl titanate and the like as catalysts, and ethylene glycol and 2-methylsuccinic acid are subjected to condensation polymerization at high temperature (230 ℃) in a high-pressure reaction kettle to form ethylene glycol polyester with the number average molecular weight of 2800-. Wangshi Zhen et al synthesized itaconic acid polyester by a biocatalysis process using itaconic acid and a diol as substrates and lipase as a catalyst. Firstly, preparing a prepolymer by enzymatic esterification for 12-24h under normal pressure; then under the vacuum condition, the itaconic acid polyester (CN 109251942A) is obtained after polycondensation for 18 to 48 hours. The method disclosed in the patent has mild reaction conditions for synthesizing the itaconic acid polyester through enzyme catalysis, reduces energy consumption, but has slow reaction speed of enzyme catalysis and longer required time.

Therefore, the development of a more efficient biocatalytic polymerization method is the focus of research.

Disclosure of Invention

In view of the above, the invention provides a preparation method of a polyester plasticizer, a product and an application thereof, and the synthesis method of the polyester plasticizer is green and environment-friendly, and has the advantages of less side reaction, less solvent consumption, small dispersion coefficient, simple operation, controllable molecular weight and the like. The polyester plasticizer obtained by the invention has the characteristics of extraction resistance, migration resistance and no toxicity, and can improve the mechanical property and low-temperature resistance of NBR.

In order to achieve the technical purpose, the invention provides the following technical scheme:

the first technical scheme is as follows: a preparation method of a polyester plasticizer comprises the following steps:

(1) carrying out esterification reaction on dihydric alcohol and a dibasic acid mixture in a nitrogen atmosphere to obtain a prepolymer;

(2) adding lipase into the prepolymer to carry out polycondensation reaction to obtain a polyester crude product;

(3) taking a crude polyester product and polydimethylsiloxane as raw materials, and carrying out grafting reaction under the action of a catalyst to obtain a crude modified polyester product;

(4) and separating and purifying the obtained crude modified polyester product to obtain the polyester plasticizer.

Further, the dihydric alcohol in the step (1) is two or more than two of 1, 3-propanediol, 1, 2-propanediol, butanediol, pentanediol, hexanediol and octanediol; the dibasic acid is one or more of succinic acid, adipic acid, sebacic acid, fumaric acid and malic acid.

Further, the molar ratio of the dihydric alcohol to the dibasic acid in the step (1) is 8:1-1: 1; the esterification reaction temperature is 100-180 ℃, and the time is 1-8 h.

Further, the Lipase in the step (2) is one of Novozym435, Novozym40086, porcine pancreatin, Candida rugosa, Lipozyme RM IM, Lipozyme TL IM and Lipase AS.

Further, the addition amount of the lipase in the step (2) is 1-10% of the mass of the prepolymer; the polycondensation reaction temperature is 50-80 ℃, the time is 12-48h, and the pressure is 200-500 Pa.

Further, the molar ratio of the crude polyester and the polydimethylsiloxane in the step (3) is 1: (0.1-0.3), wherein the dosage of the catalyst is 5 per mill of the total molar mass of the crude polyester and the polydimethylsiloxane; the catalyst is dibutyl tin dilaurate.

Further, the grafting reaction temperature in the step (3) is 140-.

Further, the separation and purification of the step (4) comprises the following specific steps: and (3) filtering the crude modified polyester product solvent by using a solvent to remove enzyme particles, removing the solvent by rotary evaporation, and drying in vacuum to obtain the polyester product. The solvent is one of tetrahydrofuran, ethyl acetate, trichloromethane and cyclohexane.

The second technical scheme is as follows: a polyester plasticizer obtained by the preparation method.

The third technical scheme is as follows: a preparation method of nitrile rubber comprises the following steps: adding carbon black, zinc oxide, stearic acid, an accelerator TMTD, an accelerator CZ, a vulcanizing agent and the polyester plasticizer according to claim 8 into raw nitrile rubber, mixing and vulcanizing.

The mass ratio of the nitrile rubber raw rubber to the polyester plasticizer is 10: (1-6).

The technical scheme is as follows: the nitrile rubber prepared by the preparation method.

Compared with the prior art, the invention has the beneficial effects that:

(1) the preparation process is simple, greatly reduces the reaction energy consumption and the difficulty of separation and purification, and compared with a direct enzyme catalysis method, the self-catalysis prepolymerization reaction reduces the acidity and polarity of the system, provides a favorable environment for the next enzyme catalysis, accelerates the reaction progress and improves the yield. The acid autocatalytic prepolymerization provides a proper catalytic environment for subsequent enzymatic reaction, so that the polycondensation reaction effect is greatly improved, the acid value of the product is low, and the thermal stability is good.

(2) The invention uses siloxane to modify polyester, the dissociation energy of Si-O-Si bond structure and Si-O bond of the main chain is far larger than that of C-O and C-C bonds, so the stability of the polyester can be improved by adopting siloxane to improve the polyester, and meanwhile, because the side chain of polydimethylsiloxane is methyl and has small volume, the flexibility of the chain is large, the cold resistance is good, and the low temperature resistance of the NBR can be obviously improved by applying the polydimethylsiloxane into the NBR.

(3) The polyester plasticizer has good compatibility with NBR, can improve the mechanical property of NBR, reduces the internal consumption of rubber products, has glass transition temperature lower than DOP, and has good low-temperature resistance. The nontoxic polyester plasticizer can be applied to various fields, and can improve the production efficiency of products.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

The parts used in the following examples are parts by weight unless otherwise specified.

The polyester product was characterized as follows:

molecular weight: after dissolving tetrahydrofuran, the solution is filtered through a 0.22 micron nylon filter membrane, polystyrene is used as an internal standard substance, and the average relative molecular weight and the molecular weight distribution index of the product are measured by a Waters 1525 gel chromatograph.

Acid value: the measurement was carried out according to the standard GB/T7304-.

Mechanical properties: the mechanical properties of the NBR test pieces were determined according to the standard GB/T528-1998.

Shore hardness: the Shore hardness of the samples was tested according to the standard GB/T531-1999.

The diols used in the following examples were mixed in equal volumes.

Example 1

(1) Succinic acid, butanediol and 1, 3-propylene glycol are used as raw materials, and the molar ratio of the alkyd is 1.5: 1, carrying out normal pressure esterification reaction, heating to 120 ℃ under the protection of nitrogen, and continuously stirring for reaction for 3 hours to obtain a prepolymer;

(2) reducing the temperature to 70 ℃ under the protection of nitrogen, adding Novozym435(5 wt% calculated by the total mass of the substrate), starting a vacuum device, controlling the pressure to 500Pa, reducing the pressure and removing water, and reacting for 12 hours to obtain a crude polyester product;

(3) mixing the polyester crude product and polydimethylsiloxane in a molar ratio of 1:0.2, carrying out grafting reaction under the action of dibutyl tin dilaurate (the dosage is 5 per mill of the total molar mass of the polyester crude product and the polydimethylsiloxane), starting the reaction at 140 ℃ for 1h, gradually heating to 180 ℃, and reacting for 3h to obtain a modified polyester crude product;

(4) adding trichloromethane into the crude modified polyester product for dissolving, filtering to remove the enzyme preparation, and performing rotary evaporation to remove the trichloromethane to obtain the polyester plasticizer.

Example 2

(1) Adipic acid, butanediol, 1, 3-propanediol and alcohol acid in a molar ratio of 1.5: 1, carrying out normal pressure esterification reaction, heating to 120 ℃ under the protection of nitrogen, and continuously stirring for reaction for 3 hours to obtain a prepolymer;

(2) reducing the temperature to 70 ℃ under the protection of nitrogen, adding Novozym435(5 wt% calculated by the total mass of the substrate), starting a vacuum device, controlling the pressure to 500Pa, reducing the pressure and removing water, and reacting for 12 hours to obtain a crude polyester product;

(3) mixing the polyester crude product and polydimethylsiloxane in a molar ratio of 1:0.2, carrying out grafting reaction under the action of dibutyl tin dilaurate (the dosage is 5 per mill of the total molar mass of the polyester crude product and the polydimethylsiloxane), starting the reaction at 140 ℃ for 1h, gradually heating to 180 ℃, and reacting for 3h to obtain a modified polyester crude product;

(4) adding trichloromethane into the crude modified polyester product for dissolving, filtering to remove the enzyme preparation, and performing rotary evaporation to remove the trichloromethane to obtain the polyester plasticizer.

Example 3

(1) Succinic acid, sebacic acid, pentanediol, octanediol and hexanediol are used as raw materials, and the molar ratio of the alkyd is 1.5: 1, carrying out normal pressure esterification reaction, heating to 120 ℃ under the protection of nitrogen, and continuously stirring for reaction for 3 hours to obtain a prepolymer;

(2) reducing the temperature to 70 ℃ under the protection of nitrogen, adding Novozym435(5 wt% calculated by the total mass of the substrate), starting a vacuum device, controlling the pressure to 500Pa, reducing the pressure and removing water, and reacting for 12 hours to obtain a crude polyester product;

(3) mixing the polyester crude product and polydimethylsiloxane in a molar ratio of 1:0.2, carrying out grafting reaction under the action of dibutyl tin dilaurate (the dosage is 5 per mill of the total molar mass of the polyester crude product and the polydimethylsiloxane), starting the reaction at 140 ℃ for 1h, gradually heating to 180 ℃, and reacting for 3h to obtain a modified polyester crude product;

(4) adding trichloromethane into the crude modified polyester product for dissolving, filtering to remove the enzyme preparation, and performing rotary evaporation to remove the trichloromethane to obtain the polyester plasticizer.

Example 4

(1) Malic acid, 1, 2-propylene glycol and hexanediol are used as raw materials, and the molar ratio of the alkyd is 8:1, carrying out normal pressure esterification reaction, heating to 100 ℃ under the protection of nitrogen, and continuously stirring for reaction for 8 hours to obtain a prepolymer;

(2) reducing the temperature to 80 ℃ under the protection of nitrogen, adding porcine pancreatin (10 wt% calculated by the total mass of the substrate), starting a vacuum device, controlling the pressure to 250Pa, reducing the pressure and removing water, and reacting for 36 hours to obtain a crude polyester product;

(3) mixing the polyester crude product and polydimethylsiloxane in a molar ratio of 1:0.1, carrying out grafting reaction under the action of dibutyl tin dilaurate (the dosage is 5 per mill of the total molar mass of the polyester crude product and the polydimethylsiloxane), starting the reaction at 140 ℃ for 1h, gradually heating to 180 ℃, and reacting for 3h to obtain a modified polyester crude product;

(4) adding trichloromethane into the crude modified polyester product for dissolving, filtering to remove the enzyme preparation, and performing rotary evaporation to remove the trichloromethane to obtain the polyester plasticizer.

Example 5

(1) Sebacic acid, pentanediol, hexanediol and octanediol are used as raw materials, and the molar ratio of the alkyd is 1:1, carrying out normal pressure esterification reaction, heating to 180 ℃ under the protection of nitrogen, and continuously stirring for reaction for 1 hour to obtain a prepolymer;

(2) reducing the temperature to 50 ℃ under the protection of nitrogen, adding Lipase AS (1 wt% calculated by the total mass of the substrate), starting a vacuum device, controlling the pressure to 400Pa, reducing the pressure and removing water, and reacting for 15 hours to obtain a polyester crude product;

(3) mixing the polyester crude product and polydimethylsiloxane in a molar ratio of 1:0.3, carrying out grafting reaction under the action of dibutyl tin dilaurate (the dosage is 5 per mill of the total molar mass of the polyester crude product and the polydimethylsiloxane), starting the reaction at 140 ℃ for 2h, gradually heating to 180 ℃, and reacting for 3h to obtain a modified polyester crude product;

(4) adding trichloromethane into the crude modified polyester product for dissolving, filtering to remove the enzyme preparation, and performing rotary evaporation to remove the trichloromethane to obtain the polyester plasticizer.

Example 6

The difference from example 1 is that step 4 is not carried out.

Example 7

The difference from example 2 is that step 4 is not carried out.

Example 8

The difference from example 3 is that step 4 is not carried out.

Comparative example 1

The difference from example 1 is that succinic acid and 1, 3-propanediol are mixed in step (1).

Comparative example 2

The difference from example 1 is that no lipase is added in step (2).

Comparative example 3

The difference from example 1 is that the pressure in step (2) is 150 Pa.

Comparative example 4

The difference from example 1 is that the esterification reaction is carried out by mixing the lipase with the diol and the diacid. Namely, the step (1) is to mix succinic acid, butanediol, 1, 3-propanediol and Novozym435 for normal pressure esterification reaction; and (2) performing polycondensation reaction on the prepolymer. The remaining steps and parameters were the same as in example 1.

Test example 1

The polyester plasticizers obtained in examples 1 to 8 and comparative examples 1 to 4 were examined for the number average molecular weight Mn, PDI, acid value and yield, and the results are shown in Table 1.

TABLE 1

As can be seen from Table 1, the number average molecular weight of the synthesized polyester of the present invention can be controlled to 2000-4000, the dispersion coefficient is lower than 1.1-1.7, and the yield can reach as high as 97%, while the yield of the polyester plasticizer which is not prepared by the method of the present invention is significantly lower than that of the examples, which shows that the raw materials and the steps of the present invention are interactive and have synergistic effect.

Test example 2

In the preparation of nitrile rubbers using polyester plasticizers obtained in examples 1 to 8, comparative examples 1 to 4 and a control (dioctyl phthalate (DOP) as a plasticizer), the specific preparation method is as follows:

weighing 100 parts of NBR raw rubber, 50 parts of carbon black CB (N330), 10 parts of polyester plasticizer, 5 parts of ZnO, 2 parts of stearic acid SA, 0.5 part of accelerant TMTD, 0.6 part of CZ and 1.5 parts of S according to parts by weight, putting the materials into a mixing roll to be mixed uniformly, and then vulcanizing and tabletting the materials by using a flat vulcanizing machine to obtain the rubber test piece.

The results of the property test of each rubber test piece are shown in Table 2.

TABLE 2

The test result shows that the polyester plasticizer prepared by the invention is beneficial to improving the hardness and tensile strength of NBR vulcanized rubber, and simultaneously has good low-temperature resistance, compared with a control group and a comparative example, the polyester plasticizers prepared by the examples 1 to 8 of the invention have obvious extraction resistance in petroleum ether, and particularly the examples 1 to 5 have the most obvious effect.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included therein.