阅读说明：本技术 一种乙二胺四乙酸酯类物质及其在制备聚氯乙烯防粘釜剂的应用 (Ethylene diamine tetraacetic acid ester substance and application thereof in preparation of polyvinyl chloride anti-sticking agent ) 是由 梁高珲 徐丹 徐彦龙 秦中宇 王磊 张起政 张宏科 于 2020-07-22 设计创作，主要内容包括：本发明公开了一种聚氯乙烯防粘釜剂,其由乙二胺衍生的羧酸酯类化合物作为前驱体,与甲醛反应得到。所述前驱体具有如下结构：<Image he="366" wi="700" file="DDA0002596624160000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>本发明的防粘釜剂合成手段简单,原料易得,并且得到的产物对釜壁的粘附力更强,是一种有效的防粘釜剂化合物。(The invention discloses a polyvinyl chloride anti-sticking agent for a kettle, which is obtained by reacting a carboxylic ester compound derived from ethylenediamine with formaldehyde as a precursor. The precursor has the following structure: the anti-sticking kettle agent has simple synthesis means and easily obtained raw materials, and the obtained product has stronger adhesion to the kettle wall, thereby being an effective anti-sticking kettle agent compound.)

1. A polyvinyl chloride kettle-sticking preventing agent precursor is characterized by having a structure shown as the following formula (I):

wherein R is¹The group is selected from H, C1-C3 alkoxy, C1-C3 acylamino, C1-C4 amino, preferably H, methoxy, methylamino, dimethylamino, acetamido.

2. The polyvinyl chloride anti-sticking agent is characterized by being obtained by reacting ethylene diamine tetraacetic acid compounds shown as a formula (I) with aldehydes, such as formaldehyde.

3. The polyvinyl chloride kettle adhesion preventing agent is characterized in that the preparation method comprises the following steps:

a) reacting ethylenediamine, an alkali solution and hydroxyacetonitrile in a reactor, and performing acidification treatment after the reaction is finished to obtain a reaction solution containing ethylenediamine tetraacetic acid;

b) adding a compound of a formula (II) into the reaction liquid obtained in the step a), adding a certain amount of acid, naturally cooling to room temperature after the reaction is finished, and neutralizing to obtain an aqueous solution containing ethylene diamine tetracetate;

c) adding aldehyde into the aqueous solution obtained in the step b) for reaction, and naturally cooling to room temperature to obtain the kettle adhesion preventing agent.

4. The polyvinyl chloride kettle adhesion preventing agent as claimed in claim 3, wherein in the step a), the alkali solution is potassium hydroxide and/or sodium hydroxide solution, and the mass ratio of alkali to ethylenediamine is 3: 1-5: 1;

the mass ratio of the hydroxy acetonitrile to the ethylenediamine is 4: 1-6: 1.

5. The polyvinyl chloride kettle-releasing agent according to claim 3 or 4, wherein in the step a), the reaction temperature is 95-110 ℃ and the reaction time is 24-36 h.

6. The polyvinyl chloride kettle-sticking preventing agent as claimed in any one of claims 3 to 5, wherein in the step a), acidification is carried out by using sulfuric acid until the pH of the reaction solution is less than 7.

7. The polyvinyl chloride kettle release agent according to any one of claims 3 to 6, wherein the molar ratio of the compound of formula (II) added to the initial ethylenediamine in step b) is from 4:1 to 5: 1.

8. The polyvinyl chloride kettle-sticking preventing agent as claimed in any one of claims 3 to 7, wherein in the step b), the supplemented acid is concentrated sulfuric acid;

the reaction temperature is between 100 ℃ and 120 ℃, and the reaction time is between 20 and 28 hours.

9. The polyvinyl chloride kettle-releasing agent according to any one of claims 3 to 8, wherein in step c), the aldehyde is formaldehyde, the concentration of the formaldehyde solution is 20 to 50 wt%, preferably 37 wt%, and the formaldehyde is added in an amount of 4 to 15 times the molar amount of the initial ethylene diamine.

10. The polyvinyl chloride anti-sticking agent for kettle as claimed in any one of claims 3 to 9, wherein in step c), the reaction temperature is 140 ℃ and the reaction time is 40-50 h.

Technical Field

The invention relates to the technical field of organic composite materials, in particular to an anti-sticking kettle agent product used in a PVC polymerization process and a preparation method thereof.

Background

Polyvinyl chloride is one of five general-purpose plastics, has excellent comprehensive performance and low price, is widely applied in various fields, and has the dosage second to that of polyethylene. The polyvinyl chloride is white amorphous structure powder, and can be used for preparing sheets, pipes, sectional materials, wires and cables, sealing plastics and preparing various food packaging and building consumables through different additives.

Depending on the polymerization process, polyvinyl chlorides can be classified into four categories: suspension process polyvinyl chloride, emulsion process polyvinyl chloride, bulk process polyvinyl chloride, and solution process polyvinyl chloride. The suspension method has the maximum yield of polyvinyl chloride, which accounts for about 80 percent of the total yield of the polyvinyl chloride. The suspension polymerization method is characterized in that the monomers are suspended and dispersed in a water phase in a microdroplet shape, an oil-soluble initiator is selected to be dissolved in the monomers, initiation is carried out in dispersed liquid drops, and the final PVC product is obtained through polymerization.

Various additives including an anti-sticking kettle agent, a dispersing agent, a defoaming agent and an initiator are required to be added in the production process of the suspension method polyvinyl chloride, and the whole polymerization process is a free radical process. Free radical single electrons can be generated in the free radical reaction process, and on one hand, the single electrons have extremely high reaction activity and react with iron with high activity to cause a kettle sticking phenomenon; on the other hand, the formation of coordination bonds between the radical singlet electrons and the wall of the reactor also causes the problem of sticking to the reactor. The superposition of the two factors leads to a more serious kettle sticking phenomenon. The kettle sticking phenomenon causes PVC to be greatly limited in the production process, and the kettle needs to be cleaned continuously. Meanwhile, the unclean kettle wall also causes the problems of a large amount of impurity particles, fish eyes and the like in the product, so that the product quality is reduced and the profit is lost.

The anti-sticking kettle agents used by various polyvinyl chloride manufacturers for producing polyvinyl chloride are mainly the following three types: "American Red", "European blue" and "Italian yellow", wherein the "Italian yellow" is used with the best effect. Italian yellow is essentially a polymer obtained by intermolecular condensation of formaldehyde and a condensed ring phenolic compound, and is mainly characterized in that oxygen is used as a ligand to form a coordination bond with metal ions between kettle walls, and an organic film is formed on the surfaces of the kettle walls and covers the surfaces of the kettle walls. Because the medium on the surface of the kettle wall has hydrophobicity, the suspension can not be in direct contact with the kettle wall, and the effect of preventing the kettle from being stuck is achieved. However, oxygen, which is a compound having a very large electronegativity, still causes the adhesion of the anti-sticking agent to the kettle wall due to its strong binding force to its peripheral electrons, resulting in the generation of impurities, foreign particles, fish eyes, and the like.

In order to better solve the problem that the adhesion between the anti-sticking agent and the kettle wall is not firm, a novel anti-sticking agent is developed so as to be better applied to actual production.

Disclosure of Invention

The invention aims to mainly solve the problem that an anti-kettle agent used in the production process of polyvinyl chloride by the existing suspension method is not firmly adhered to the kettle wall, and provides a novel anti-kettle agent.

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

in a first aspect of the present invention, there is provided an ethylenediaminetetraacetic acid ester compound having a structure represented by the following formula (I)

Wherein, in the formula (I), R¹The group can be H, C1-C3 alkoxy, C1-C3 acylamino, C1-C4 amino, preferably H, methoxy, methylamino, dimethylamino, acetamido, R¹The group may be in the para or meta position relative to the ester group.

The invention also relates to the application of the ethylene diamine tetraacetic acid ester compound in preparing the polyvinyl chloride anti-sticking agent, which is used as a precursor of the anti-sticking agent and reacts with formaldehyde to obtain the anti-sticking agent.

The invention also relates to a preparation method of the polyvinyl chloride kettle adhesion preventing agent, which comprises the following steps:

a) adding ethylenediamine into a reactor, then adding an alkali solution, slowly adding hydroxyacetonitrile into the reactor for reaction, stopping the reaction when the ethylenediamine is completely reacted, and performing acidification treatment to obtain a reaction solution containing ethylenediamine tetraacetic acid;

b) adding a compound of a formula (II) into the reaction liquid obtained in the step a), slowly adding a certain amount of acid for reaction, naturally cooling to room temperature after the reaction is finished, and neutralizing with alkali liquor to obtain an aqueous solution containing ethylene diamine tetracetate;

wherein R is¹As defined above;

c) adding formaldehyde solution into the aqueous solution obtained in the step b), reacting until red solid is generated, and naturally cooling to room temperature to obtain the anti-sticking kettle agent.

In the preparation method, the alkali solution in the step a) is potassium hydroxide and/or sodium hydroxide solution, the concentration is not particularly limited, for example, the concentration can be 10-20% (g/ml), and the mass ratio of the effective alkali to the ethylenediamine after the alkali solution is added is 3: 1-5: 1;

the mass ratio of the hydroxy acetonitrile to the ethylenediamine is between 4:1 and 6: 1;

the reaction temperature is 95-110 ℃, and the reaction time is 24-36 h;

the acidification can be carried out by adopting sulfuric acid with the concentration of 8-15% (V/V) until the pH value of the reaction solution is less than 7;

in step b), the molar ratio of the added compound of the formula II) to the initial ethylenediamine is between 4:1 and 5: 1;

the supplemented acid is concentrated sulfuric acid which is used as a catalyst for esterification reaction and provides a strong acid environment, and the addition amount of the supplemented acid is conventional and can be determined by a person skilled in the art according to actual conditions;

the reaction temperature is between 100 ℃ and 120 ℃, and the reaction time is 20-28 h;

the alkali liquor used for neutralization is 30-45 wt% potassium hydroxide and/or sodium hydroxide solution, and the pH value is about neutral.

In said step c), the formaldehyde solution may be added in an amount of 20 to 50 wt%, preferably 37 wt% of formaldehyde in water, the formaldehyde being added in excess with respect to the starting ethylenediamine, for example in a molar amount of 4 to 15 times the starting ethylenediamine;

the reaction temperature is 140 ℃ and 160 ℃, and the reaction time is 40-50 h.

The anti-sticking agent prepared by the invention is prepared into aqueous solution by the same method as the commercially available anti-sticking kettle, and is directly sprayed by a high-pressure water gun.

The invention has the beneficial effects that:

the anti-sticking agent prepared by the invention is firmly combined with the kettle wall by combining with various coordination actions of aromatic ring, carbonyl and nitrogen, is not easy to fall off in production, greatly reduces the kettle cleaning times, simplifies the production process and improves the production efficiency; the prepared product has few fish eyes and high plasticizer absorption, all reaches the high-grade product standard, and is easy for downstream processing.

Detailed Description

The specific embodiments of the present invention are further illustrated by the following examples, which are only for the understanding of the present invention and the scope of protection is not limited by the following examples.