阅读说明：本技术 二元醇改性petg聚酯切片及其生产工艺 (Glycol modified PETG polyester chip and production process thereof ) 是由 马德义 王祖宏 胡士清 杜永峰 胡耀 那海锋 夏佳 于 2019-08-30 设计创作，主要内容包括：本发明公开了一种二元醇改性的PETG聚酯切片,是由以下原料制成：对苯二甲酸、新戊二醇、二甘醇、乙二醇的摩尔比为1：(0.1～0.5)：(0.05～0.1)：(0.6～0.8)。本发明采用成本相对较低、易得的对苯二甲酸、新戊二醇、二甘醇、乙二醇作为反应原料,在连续聚合装置上生产质量稳定、颜色透明性等满足片材、板材、瓶用的二元醇改性的PETG聚酯切片。(The invention discloses a glycol modified PETG polyester chip, which is prepared from the following raw materials: the molar ratio of terephthalic acid, neopentyl glycol, diethylene glycol and ethylene glycol is 1: (0.1-0.5): (0.05-0.1): (0.6-0.8). The invention adopts terephthalic acid, neopentyl glycol, diethylene glycol and ethylene glycol which are relatively low in cost and easy to obtain as reaction raw materials, and produces the glycol-modified PETG polyester chip which has stable quality, color transparency and the like and meets the requirements of sheets, plates and bottles on a continuous polymerization device.)

1. The glycol-modified PETG polyester chip is characterized by being prepared from the following raw materials:

the molar ratio of terephthalic acid, neopentyl glycol, diethylene glycol and ethylene glycol is 1: (0.1-0.5): (0.05-0.1): (0.6-0.8).

2. The glycol-modified PETG polyester chip according to claim 1, wherein the molar ratio of neopentyl glycol is 0.15-0.5.

3. The glycol-modified PETG polyester chip according to claim 1, further comprising a catalytic amount of catalyst, wherein the catalyst is ethylene glycol antimony, antimony acetate, cobalt acetate.

4. The glycol-modified PETG polyester chip according to claim 1, wherein the melt intrinsic viscosity of the glycol-modified PETG polyester chip is controlled to be in the range of 0.70-0.85 dl/g.

5. A process for the preparation of glycol-modified PETG polyester chip as claimed in any one of claims 1 to 4, comprising the steps of:

mixing terephthalic acid, neopentyl glycol, diethylene glycol and ethylene glycol according to the proportion, and carrying out copolymerization reaction under the action of a catalyst to obtain the glycol modified PETG polyester chip.

6. The method for preparing the glycol-modified PETG polyester chip according to claim 5, wherein the catalyst is ethylene glycol antimony, antimony acetate or cobalt acetate.

7. The method of making the glycol-modified PETG polyester chip of claim 5, comprising the steps of:

firstly, preparing slurry in batches according to a ratio, adding neopentyl glycol, diethylene glycol and ethylene glycol into a preparation tank, then adding terephthalic acid and finally adding a catalyst, wherein the pulping time of each batch is 30-80 minutes, preparing the two pulping tanks in turn, putting the prepared slurry into a slurry finished product tank, and continuously feeding the slurry into a first esterification reaction kettle from the finished product tank;

and the second step, the esterification reaction is completed in two steps: the first esterification reaction kettle has the reaction pressure of about 100Kpa, the temperature of 255-265 ℃ and the reaction time of 2-3 h, and then the mixture is sent into a second esterification reaction kettle, the reaction pressure of the second esterification reaction kettle is about 20Kpa, the reaction temperature of 265-270 ℃ and the reaction time of 1-2 h;

third, polycondensation reaction

The polycondensation reaction is carried out under vacuum condition and is completed in three steps: the reaction temperature of the pre-polycondensation reaction kettle is 270-275 ℃, the vacuum degree is required to be 6000-12000 Pa, and the reaction time is 50-90 minutes; the reaction temperature of the secondary polycondensation reaction kettle is 275-280 ℃, the vacuum degree is required to be 600-1200 Pa, and the reaction time is 50-90 minutes; the reaction temperature of the final polycondensation reaction kettle is 280-290 ℃, the vacuum degree is required to be 60-200 Pa, and the reaction time is 50-90 minutes;

the materials are continuously overflowed among the reaction kettles through potential difference, pressure difference and gear pumps, and the liquid level, pressure and temperature of each reaction kettle are controlled by a distributed control system provided by Zhejiang central control, so that the continuous and stable quality of the PETG product is ensured;

the PETG is obtained from the final polycondensation reaction kettle in a molten state, and the intrinsic viscosity of the melt is controlled within the range of 0.70-0.85 dl/g;

fourthly, discharging and granulating

And discharging the PETG melt from the final polycondensation reaction kettle through a melt gear pump, pressurizing and filtering, and feeding the filtered melt into a finished product bin after belt casting, underwater grain cutting, drying and vibration separation to obtain the glycol modified PETG polyester chips.

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a glycol modified PETG polyester chip and a production process thereof.

Background

The PVC heat-shrinkable film used for printing, labeling and the like of food packaging has toxic PVC heat-shrinkable films which are used for more than 20 ten thousand tons in China every year, and PVC materials are forbidden by legislation in developed countries such as Europe, America, Japan and Korean. China is also gradually banning toxic PVC products from being used in packaging in the food and beverage industries.

The PETG polyester is fully called polyethylene glycol terephthalate-1, 4-cyclohexane dimethanol ester, is a non-crystalline polyester, and has the characteristics of toughness, weather resistance, chemical resistance, environmental protection, economy and the like. PETG is the best product for replacing PVC with good transparency, printing performance, high heat shrinkage rate and environmental protection. Moreover, PETG products have great development space in the packaging industries of sheets, plates, bottles and the like. PETG polyester was first copolymerized from terephthalic acid, ethylene glycol, and 1, 4-Cyclohexanedimethanol (CHDM) by Eschmann (EASTMAN) USA. This production technology is also adopted by SK corporation of korea. The main raw material CHDM of the technology is expensive and not easy to obtain; the synthesized PETG polyester has higher price; the CHDM copolymerization modification is adopted to generate harmful chemical substance methanol in the reaction process, and the methanol is toxic and flammable, pollutes the environment and is harmful to the personal safety and health.

Several companies exist in China, neopentyl glycol (NPG) is used for replacing CHDM to carry out modification copolymerization to produce PETG, for example, CN102558517A discloses ecological multifunctional ternary copolymerization PETG polyester, a preparation method thereof and a method for preparing a unidirectional stretching heat shrinkage film by the polyester, wherein the ecological multifunctional ternary copolymerization PETG polyester is prepared by copolymerizing terephthalic acid, neopentyl glycol and ethylene glycol, and the molar ratio of the terephthalic acid, the neopentyl glycol and the ethylene glycol is 1: 0.1-0.65: 1.2-1.75.

Neopentyl glycol (NPG) is used for replacing CHDM to modify and copolymerize to produce PETG, and the produced neopentyl glycol modified PETG has poor toughness and brittle products; in addition, the production process needs to use a batch device for production, so that the following problems are generally existed: batch production is carried out, and the production cost is high; the product of each batch is different, and the head and tail materials of one batch are different; the product has color difference, can only be used in the industry of 'shrink film' with low requirements on color phase, and can not enter the industries and products with high requirements on transparency and color, such as sheets, plates, bottles and the like.

Disclosure of Invention

The invention aims to provide a novel glycol-modified PETG polyester chip which has good toughness, high transparency and no color difference.

Another object of the present invention is to provide a continuous non-batch process for producing the above-described glycol-modified PETG polyester chip.

The invention provides a glycol modified PETG polyester chip, which uses a certain amount of neopentyl glycol in a formula, simultaneously adds diethylene glycol, and the combined use of the neopentyl glycol and the diethylene glycol not only replaces CHDM in the American technology, but also has better performance than the PETG polyester chip prepared by only using the neopentyl glycol when reducing the cost; moreover, the inventor finds that: due to the addition of the diglycol, the dosage of the glycol is also reduced unexpectedly, and the cost of the PETG is also greatly reduced.

The invention provides a glycol-modified PETG polyester chip, which is prepared from the following raw materials:

the molar ratio of terephthalic acid (PTA), neopentyl glycol (NPG), diethylene glycol (DEG) and ethylene glycol (MEG) is 1: (0.1-0.5): (0.05-0.1): (0.6-0.8).

The molar ratio of the neopentyl glycol is preferably 0.15-0.5.

The glycol-modified PETG polyester chip also comprises a catalytic amount of catalyst, wherein the catalyst is ethylene glycol antimony, antimony acetate and cobalt acetate.

The melt intrinsic viscosity of the glycol modified PETG polyester chip is controlled within the range of 0.70-0.85 dl/g.

The invention also provides a preparation method of the glycol modified PETG polyester chip, which comprises the following steps:

mixing terephthalic acid, neopentyl glycol, diethylene glycol and ethylene glycol according to the proportion, and carrying out copolymerization reaction under the action of a catalyst to obtain the glycol modified PETG polyester chip.

The catalyst can be ethylene glycol antimony, antimony acetate, cobalt acetate and the like.

The preparation method of the glycol-modified PETG polyester chip comprises the following steps:

firstly, preparing slurry in batches according to a ratio, adding neopentyl glycol, diethylene glycol and ethylene glycol into a preparation tank, then adding terephthalic acid and finally adding a catalyst, wherein the pulping time of each batch is 30-80 minutes, preparing the two pulping tanks in turn, putting the prepared slurry into a slurry finished product tank, and continuously feeding the slurry into a first esterification reaction kettle from the finished product tank;

and the second step, the esterification reaction is completed in two steps: the first esterification reaction kettle has the reaction pressure of about 100Kpa, the temperature of 255-265 ℃ and the reaction time of 2-3 h, and then the mixture is sent into a second esterification reaction kettle, the reaction pressure of the second esterification reaction kettle is about 20Kpa, the reaction temperature of 265-270 ℃ and the reaction time of 1-2 h;

third, polycondensation reaction

The polycondensation reaction is carried out under vacuum condition and is completed in three steps: the reaction temperature of the pre-polycondensation reaction kettle is 270-275 ℃, the vacuum degree is required to be 6000-12000 Pa, and the reaction time is 50-90 minutes; the reaction temperature of the secondary polycondensation reaction kettle is 275-280 ℃, the vacuum degree is required to be 600-1200 Pa, and the reaction time is 50-90 minutes; the reaction temperature of the final polycondensation reaction kettle is 280-290 ℃, the vacuum degree is required to be 60-200 Pa, and the reaction time is 50-90 minutes;

the materials are continuously fed between the reaction kettles through potential difference, pressure difference and a gear pump, and the parameters of liquid level, pressure (vacuum), temperature and the like of each reaction kettle are controlled to be stabilized within a certain range by a Distributed Control System (DCS) provided by Zhejiang central control, so that the continuous and stable quality of the PETG product is ensured;

the PETG is obtained from the final polycondensation reaction kettle in a molten state, and the intrinsic viscosity of the melt is controlled according to different purposes, wherein the control range is between 0.70 dl/g and 0.85 dl/g;

fourthly, discharging and granulating

The PETG fusant discharged from the final polycondensation reaction kettle is discharged through a fusant gear pump, pressurized and sent into a candle core type filter (the filtering precision is 20-40 um) under certain pressure (7-20 MPa), impurities and condensed particles in the fusant are filtered, and the filtered fusant enters a finished product bin after being cast, granulated under water, dried and separated by vibration to obtain the glycol modified PETG polyester chips.

The invention also tries to use other dihydric alcohol, such as benzene ring-containing dihydric alcohol and aliphatic dihydric alcohol, but the requirements on the catalyst in the production are particularly high, and the production process is difficult.

Due to the adoption of the technical scheme, the invention has the following advantages and beneficial effects:

the invention adopts terephthalic acid (PTA), neopentyl glycol (NPG), diethylene glycol (DEG) and ethylene glycol (MEG) which have relatively low cost and are easy to obtain as reaction raw materials, and produces the glycol modified PETG polyester chip which has stable quality, color transparency and the like and meets the requirements of sheets, plates and bottles on a continuous polymerization device.

Compared with PETG polyester chips prepared by CHDM modification, the invention has the advantages of great cost: when the invention is used for producing one ton of product PETG, the consumed raw materials are 860 kg of terephthalic acid (PTA), 50-270 kg of neopentyl glycol (NPG), 25-55 kg of diethylene glycol (DEG), 190 kg of ethylene glycol (MEG), the raw material consumption of PETG prepared by CHDM in the prior art is 860 kg of PTA, 250-340 kg of MEG and 100-300 kg of CHDM, because the price of CHDM is higher than that of NPG by about 20000 RMB per ton on average, and the MEG consumption is more when CHDM is used, although the amount of DEG added may be reduced compared to when NPG is used, since the amount of DEG added and the cost of price are low, through data comparison and combination with the current raw material market, the cost per ton of NPG and DEG modification can be reduced by 3000-; the production process does not produce any toxic and harmful by-product, and has environmental protection advantage; the raw materials are easily available.

Compared with the PETG which is modified by NPG, the product of the invention has better performance, and particularly, the toughness of the product is obviously improved compared with the PETG which is modified by NPG; color transparency and the like for sheets, plates and bottles; the MEG dosage is reduced, and the production cost is lower.

Compared with the production of an intermittent device, the production process has stable product quality; the product quality is better (especially on the product color phase); the production cost is lower. Can be produced stably in large batch and meet the increasing requirements.

Detailed Description

The following examples are provided to illustrate specific embodiments of the present invention.

Terephthalic Acid (PTA) used in the examples of the present invention was obtained from Jiangyin Hanbang petrochemical Co., Ltd., neopentyl glycol (NPG) was obtained from Ginksfelder BASF Co., Ltd., diethylene glycol (DEG) was obtained from Sabite petroleum base Co., ethylene glycol (MEG) was obtained from Sabic Co., Ltd., and ethylene glycol antimony catalyst was obtained from Liaoyang synthetic catalyst Co., Ltd.