阅读说明：本技术 一种食品接触材料用高分子聚酯的制备方法 (Preparation method of high-molecular polyester for food contact material ) 是由 徐文军 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种食品接触材料用高分子聚酯的制备方法,按原料配比投入1号反应釜,加入硫酸铜作催化剂；将第一步反应的混合物抽入1号静置塔中,将上层水液放出,中层酯化物抽入2号反应釜,下层少量固体物为硫酸铜,经烘干投入1号反应釜；在2号反应釜中加入正辛醇,与第二步抽入的酯化物混合,加入硫酸铜作催化剂；将第三步反应的混合物抽入2号静置塔中,上层水液放出,中层聚酯物抽入真空釜,下层少量固体物为硫酸铜,经烘干投入2号反应釜；将第四步抽入真空釜的聚酯进行脱水,抽真空即得高分子聚酯。本发明可合成符合食品接触材料法规正清单中的高分子聚酯,从而满足食品接触材料领域对于高分子聚酯的应用需求。(The invention discloses a preparation method of macromolecular polyester for food contact materials, which comprises the steps of putting the raw materials into a No. 1 reaction kettle according to the mixture ratio, and adding copper sulfate as a catalyst; pumping the mixture obtained in the first step into a No. 1 standing tower, discharging the upper layer water solution, pumping the middle layer esterified substance into a No. 2 reaction kettle, drying the lower layer solid substance which is copper sulfate, and putting into the No. 1 reaction kettle; adding n-octanol into the No. 2 reaction kettle, mixing with the ester extracted in the second step, and adding copper sulfate as a catalyst; pumping the mixture obtained in the third step into a No. 2 standing tower, discharging the upper layer water solution, pumping the middle layer polyester into a vacuum kettle, drying the lower layer with a small amount of solid copper sulfate, and putting into a No. 2 reaction kettle; and dehydrating the polyester pumped into the vacuum kettle in the fourth step, and vacuumizing to obtain the high-molecular polyester. The invention can synthesize the high molecular polyester which meets the positive list of food contact material regulations, thereby meeting the application requirements of the food contact material field for the high molecular polyester.)

1. A preparation method of high molecular polyester for food contact material is characterized by comprising the following steps:

(1) putting 76 parts of 1, 2-propylene glycol, 90 parts of 1, 3-butanediol, 90 parts of 1, 4-butanediol and 438 parts of adipic acid into a No. 1 reaction kettle, simultaneously adding 10 parts of copper sulfate as a catalyst, and reacting for 1-3 hours at the temperature of 185 ℃ and the stirring speed of 30-80 rpm;

(2) pumping the mixture of the first step into a No. 1 standing tower, discharging the upper layer water liquid after 1 hour, pumping the middle layer esterified substance into a No. 2 reaction kettle, drying the lower layer of the mixture to put the mixture into the No. 1 reaction kettle, and recycling the catalyst;

(3) adding 50-90 parts of n-octanol into a No. 2 reaction kettle, mixing with the ester extracted in the second step, adding 12 parts of copper sulfate as a catalyst, and reacting for 2-3 hours at the temperature of 120-;

(4) pumping the mixture obtained in the third step into a No. 2 standing tower, discharging the upper layer water liquid after 1 hour, pumping the middle layer polyester into a vacuum kettle, drying the lower layer with a small amount of solid copper sulfate, and putting into a No. 2 reaction kettle, so that the catalyst can be recycled;

(5) and (3) dehydrating the polyester pumped into the vacuum kettle in the fourth step, and vacuumizing for 0.5-1.0 hour under the condition of-0.1 MPa to obtain the high-molecular polyester.

2. The process for producing a high-molecular polyester for food contact materials according to claim 1, wherein: the copper sulfate in the step (2) is not compatible with various raw materials, has a density higher than that of each raw material, and is always positioned at the bottom layer of the mixture.

3. The process for producing a high-molecular polyester for food contact materials according to claim 1, wherein: when 60 parts of n-octanol is used in the step (3), 1200 dalton polyester with a viscosity of 1.0Pa.s at 25 ℃ can be obtained.

Technical Field

The invention relates to the field of preparation methods of food-grade high-molecular polyester, in particular to a preparation method of high-molecular polyester for food contact materials.

Background

ZL201110432374.7 patent discloses a low viscosity unsaturated polyester and its application, mainly by dihydric alcohol, saturated dibasic acid and unsaturated dibasic acid polymerization to get final product, this preparation method has selected and similar sebacic acid smell heavier raw materials, and phthalic acid this is apt to produce phthalate ester toxic substance, the polyester prepared by this invention is although the viscosity is low, the molecular weight is only 500-.

ZL201310228615.5 patent discloses an environment-friendly polyester resin and a production process, the patent takes purified terephthalic acid, diethylene glycol, ethylene glycol, neopentyl glycol, plastic chip waste and the like as raw materials to synthesize the polyester resin, the molecular weight of the synthesized polyester resin is overlarge, and meanwhile, the plastic chip waste is taken as the raw material, so that the polyester resin obviously cannot be used in the field of food contact materials.

ZL201210237138.4 patent discloses a PVC polyester plasticizer material, which is prepared by melt polycondensation of adipic acid, trimethylolpropane, PVC and other raw materials, the preparation method has more side reactions and poor controllability of intermediate products, belongs to the application field of polyester, and cannot be used in the application field of food contact materials.

ZL201310244270.2 patent discloses a high molecular polyester plasticizer and a preparation method and application thereof, the preparation method takes 2-propyl heptanol, 1-3-dimethyl propylene glycol, neopentyl glycol and adipic acid as raw materials to prepare high molecular polyester, and the raw materials do not belong to raw materials allowed by Chinese GB9685 and European Union 10/2011/EU food contact material regulations and cannot be applied to the field of food contact materials.

Disclosure of Invention

The invention aims to overcome the technical defects and provides a preparation method of high polymer polyester for food contact materials, which selects raw materials recommended by food contact material laws and regulations in China and European Union to synthesize the high polymer polyester in accordance with the positive list of the food contact material laws and regulations, thereby meeting the application requirements of the field of the food contact materials on the high polymer polyester.

In order to solve the problems, the technical scheme of the invention is as follows: a preparation method of high molecular polyester for food contact material comprises the following steps:

(1) putting 76 parts of 1, 2-propylene glycol, 90 parts of 1, 3-butanediol, 90 parts of 1, 4-butanediol and 438 parts of adipic acid into a No. 1 reaction kettle, simultaneously adding 10 parts of copper sulfate as a catalyst, and reacting for 1-3 hours at the temperature of 185 ℃ and the stirring speed of 30-80 rpm;

(2) pumping the mixture of the first step into a No. 1 standing tower, discharging the upper layer water liquid after 1 hour, pumping the middle layer ester into a No. 2 reaction kettle, drying the lower layer to put into the No. 1 reaction kettle, and recycling the catalyst;

(3) adding 50-90 parts of n-octanol into a No. 2 reaction kettle, mixing with the ester extracted in the second step, adding 12 parts of copper sulfate as a catalyst, and reacting for 2-3 hours at the temperature of 120-;

(4) pumping the mixture obtained in the third step into a No. 2 standing tower, discharging the upper layer water liquid after 1 hour, pumping the middle layer polyester into a vacuum kettle, drying the lower layer with a small amount of solid copper sulfate, and putting into a No. 2 reaction kettle, so that the catalyst can be recycled;

(5) and (3) dehydrating the polyester pumped into the vacuum kettle in the fourth step, and vacuumizing for 0.5-1.0 hour under the condition of-0.1 MPa to obtain the high-molecular polyester.

Further, the copper sulfate in the step (2) is not compatible with various raw materials, has a density higher than that of each raw material, and is always positioned at the bottom layer of the mixture.

Further, when 60 parts of n-octanol is used in the step (3), a 1200 dalton polyester with a viscosity of 1.0pa.s at 25 ℃ can be obtained.

Compared with the prior art, the invention has the advantages that:

(1) the catalyst copper sulfate can be recycled, and the environmental pollution caused by concentrated sulfuric acid in the traditional esterification reaction is avoided;

(2) the synthetic raw materials are recommended by laws and regulations of Chinese and European Union food contact materials, do not have pungent smell, and the polyester obtained after esterification reaction is basically tasteless and meets the requirements of laws and regulations of food contact materials;

(3) the reaction adopts an intermittent operation mode, can realize continuous production and has high efficiency;

(4) the molecular weight of the polyester can be controlled to be more than 1000 daltons through a key process, the viscosity at 25 ℃ is 0.9-1.8Pa.s, and the polyester is very suitable for being used in downstream industries.

Detailed Description

The present invention is further described below by way of specific examples, but the present invention is not limited to only the following examples. Variations, combinations, or substitutions of the invention, which are within the scope of the invention or the spirit, scope of the invention, will be apparent to those of skill in the art and are within the scope of the invention.

Example one

A preparation method of high molecular polyester for food contact material comprises the following steps:

(1) putting 76 parts of 1, 2-propylene glycol, 90 parts of 1, 3-butanediol, 90 parts of 1, 4-butanediol and 438 parts of adipic acid into a No. 1 reaction kettle, adding 10 parts of copper sulfate as a catalyst, and reacting for 1 hour at 160 ℃ and at a stirring speed of 30 revolutions per minute;

(2) pumping the mixture of the first step into a No. 1 standing tower, discharging the upper layer water liquid after 1 hour, pumping the middle layer ester into a No. 2 reaction kettle, drying the lower layer to put into the No. 1 reaction kettle, and recycling the catalyst;

(3) adding 50 parts of n-octanol into a No. 2 reaction kettle, mixing with the ester extracted in the second step, adding 12 parts of copper sulfate as a catalyst, and reacting for 2 hours at the temperature of 120 ℃ and the stirring speed of 60 r/min;

(4) pumping the mixture obtained in the third step into a No. 2 standing tower, discharging the upper layer water liquid after 1 hour, pumping the middle layer polyester into a vacuum kettle, drying the lower layer with a small amount of solid copper sulfate, and putting into a No. 2 reaction kettle, so that the catalyst can be recycled;

(5) and (3) dehydrating the polyester pumped into the vacuum kettle in the fourth step, and vacuumizing for 0.5 hour under the condition of-0.1 MPa to obtain the high-molecular polyester.

Example two

A preparation method of high molecular polyester for food contact material comprises the following steps:

(1) putting 76 parts of 1, 2-propylene glycol, 90 parts of 1, 3-butanediol, 90 parts of 1, 4-butanediol and 438 parts of adipic acid into a No. 1 reaction kettle, adding 10 parts of copper sulfate as a catalyst, and reacting for 3 hours at 185 ℃ and at a stirring speed of 80 r/min;

(2) pumping the mixture of the first step into a No. 1 standing tower, discharging the upper layer water liquid after 1 hour, pumping the middle layer ester into a No. 2 reaction kettle, drying the lower layer to put into the No. 1 reaction kettle, and recycling the catalyst;

(3) adding 90 parts of n-octanol into a No. 2 reaction kettle, mixing with the ester extracted in the second step, adding 12 parts of copper sulfate as a catalyst, and reacting for 3 hours at the temperature of 155 ℃ and at the stirring speed of 90 revolutions per minute;

(4) pumping the mixture obtained in the third step into a No. 2 standing tower, discharging the upper layer water liquid after 1 hour, pumping the middle layer polyester into a vacuum kettle, drying the lower layer with a small amount of solid copper sulfate, and putting into a No. 2 reaction kettle, so that the catalyst can be recycled;

(5) and (3) dehydrating the polyester pumped into the vacuum kettle in the fourth step, and vacuumizing for 1.0 hour under the condition of-0.1 MPa to obtain the high-molecular polyester.

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 present invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.