CN1931893A

CN1931893A - Prepn process of PET/PTT copolyester

Info

Publication number: CN1931893A
Application number: CN 200610117034
Authority: CN
Inventors: 崔晶; 王朝生; 张玉梅; 王华平; 王强华; 张传雄
Original assignee: Donghua University
Current assignee: Donghua University
Priority date: 2006-10-12
Filing date: 2006-10-12
Publication date: 2007-03-21

Abstract

The present invention discloses preparation process of PET/PTT copolyester with terephthalic acid, 1, 3-propylene glycol and glycol, and the preparation process includes one esterification course and one ester exchange course. The PET/PTT copolyester has intrinsic viscosity of 0.65-0.8 dL/g. The present invention has the advantages of simple process, need of only one polymerizing kettle, high product purity, high product quality and wide application foreground in fiber and engineering plastic fields.

Description

The preparation method of PET/PTT copolyesters

Technical field

The present invention relates to field of textiles, relate in particular to the preparation method of a kind of little blocked copolyester PET/PTT.

Background technology

Poly(Trimethylene Terephthalate) (PTT) is the newcomer of thermoplastic polyester, it is the successful first synthetic resin of nineteen forty-one U.S.'s shell chemical company (Shell), be with terephthalic acid (TPA) and 1, ammediol (PDO) is by the polyester of polycondensation preparation.PTT is used for fiber industry the earliest, but PTT has the physicals close with PET, and processing forming is better than PBT, is a kind of very promising engineering plastics therefore.However, PTT is with respect to the high still comparison distinct issues of traditional polyester material price.Do not realize suitability for industrialized production at China PDO especially, most of from external import, and the polymerization process more complicated of conventional P TT, production unit is required so just to make the price of PTT be higher than conventional polyester far away also than higher.Moreover polymerization gained PTT product can not satisfy the application of spinning and engineering plastics aspect because limiting viscosity is lower.Secondly, PTT compares with PET exactly and replaces ethylene glycol to make with propylene glycol since in molecular chain many methylene radical, molecular flexibility increases, so fusing point obviously reduces, and only has an appointment about 227 ℃, second-order transition temperature also obviously reduces.So just do not caused poor heat stability, the intensity of PTT high and high temperature dimensional stability fiber is bad, particularly many predicted performances of PTT can not demonstrate fully in post-treatment.

With this understanding, Many researchers is conceived to seek a kind of mode of economical rationality, can make the premium properties of PTT be able to maximum performance.Adopt PTT and PET copolymerization mode that it is carried out modification, can optimize product performance and also can reduce production costs to a certain extent.2003, people such as Won Sik Yoon adopted the DMT route to successfully synthesize the PTT/PET multipolymer, but also had following problem with regard to its performance: at first the polymerization degree is not high; Secondly, this method is produced copolyesters product more complicated on control of process condition, is attended by more by product and generates; Moreover prepared copolymerization product is a segmented copolymer, and from macroscopic perspective, such multipolymer morphological structure heterogeneity produces a very large impact later performance.

Summary of the invention

Technical problem to be solved by this invention is to provide the preparation method of a kind of little blocked copolyester PET/PTT, to address the deficiencies of the prior art.

The present invention adopts the production unit of traditional polyester, with terephthalic acid (TPA), 1, ammediol (PDO), ethylene glycol (EG) are raw material, adopt the production route of TPA, change ethylene glycol (EG) and 1, the ingredient proportion of ammediol (PDO), produce the little blocked copolyester of PTT/PET of a series of different ratioss, the concrete steps of this method are:

1) phthalic acid (TPA) and 1, ammediol (PDO), ethylene glycol (EG) carry out esterification: its molar ratio is TPA/ (PDO+EG)=1: 1.4, temperature of reaction is 240-250 ℃, the fractional column column top temperature is 80-120 ℃, whether reaction was carried out 3-4 hour, weigh with the amount of water generation reaction to react completely.

2) esterification reaction product carries out precondensation: temperature of reaction is 260-270 ℃, reacts 20-40 minute.

3) the precondensation product is carried out polycondensation: vacuumize, temperature of reaction is 270-285 ℃, and reacting kettle inner pressure is at 50-150Pa.

When wherein carrying out polycondensation, bigger as PDO content, copolymerization temperature can omit low spot, otherwise can cause thermal destruction.

Above-mentioned reaction all is to finish in a polymeric kettle.

The most handy high-purity nitrogen bubbling is driven oxygen away before esterification feeds intake, anti-oxidation.

In described esterification, preferably add tetrabutyl titanate, its amount ranges is 10～100ppm/gTPA, tetrabutyl titanate is the catalyzer as esterification.

In described polycondensation, preferably add tetrabutyl titanate, zinc acetate and trimethyl phosphite 99; Wherein the total content of tetrabutyl titanate and zinc acetate is 150～400ppm/gTPA, and the consumption of trimethyl phosphite 99 is 50～150ppm/gTPA.Wherein tetrabutyl titanate and zinc acetate are as composite catalyst, and trimethyl phosphite 99 is as stablizer.

The molar ratio of composite catalyst tetrabutyl titanate and zinc acetate can be adjusted according to the input ratio of PDO and EG.

Essence of the present invention is to use traditional polyester production facility, adopts the production route of TPA to produce the PET/PTT copolyesters, and other parts in preparation process are then similar to traditional PET production technique.Can also add additive according to product needed in process of production, as matting agent, lubricant etc.Add stablizer and can reduce the DeR of copolyesters in polymerization process, reduce the generation of by product, improve chipping qualities.It is 0.65～0.8dL/g that products obtained therefrom gets inherent viscosity, and this viscosity has satisfied the application that can satisfy spinning and part engineering plastics aspect.

Method of the present invention can the good copolyester section of obtained performance, can reduce production costs greatly again, satisfies the demand of actual production.

Embodiment

To come by concrete example the present invention is further described below, production technique of the present invention near with the production process of traditional polyester, below carried out detailed elaboration, therefore the example below describes main consumption to material and catalyzer and additive.

The part index number testing method of PET/PTT is as follows in example:

Limiting viscosity (IV):

Use Ubbelohde viscometer, solvent is 1: 1 phenol-tetrachloroethane (mass ratio), and temperature is 25 ± 0.1 ℃, and strength of solution is 0.5g/100ml.

Content of carboxyl end group (COOH):

Adopt chemical titration.Copolyesters is dissolved in the mixing solutions (mass ratio 7: 3) of neighbour-cresols and chloroform, adds dibromothymolsulfonphthalein as indicator, the ethanolic soln with the potassium hydroxide of 0.05N carries out titration then.

Adopt 3L to have the stainless steel polymeric kettle of whipping appts in example, still adopts the oil bath heating jacket outward and has the water of condensation interlayer to carry out temperature control.Still top has and links to each other with vacuum pump and channel of nitrogen, every temperature employing computer observing and controlling of whole process are arranged.

Example 1:(EG: PDO=5: 5)

In the esterification stage, according to TPA: (EG+PDO)=feed intake at 1: 1.4, EG: PDO=5 wherein: 5.The reaction beginning slowly heats up, and treats to begin to stir after the fusion, and esterification reaction temperature is controlled at 240 ℃, and the temperature control of fractional column capital is at 100 ℃, and reaction is carried out stopping in 3.5 hours, weighs with aquifer yield.Polycondensation begins slowly to vacuumize, and temperature slowly rises, and whole temperature control is at 280 ℃, drives oxygen away with high purity nitrogen bubbling, anti-oxidation before esterification and polycondensation feed intake.Add tetrabutyl titanate (50ppm/gTPA) as catalyzer in Esterification Stage; Polycondensation phase adding zinc acetate (200ppm/gTPA) and tetrabutyl titanate (100ppm/gTPA) mixture are as catalyzer, the catalyzer of all proportionings is that optimum proportion is thrown in according to ET5 all, other adds the stablizer trimethyl phosphite 99, reaction late phase reaction still internal pressure is controlled at 120Pa, and reaction terminating is judged according to the moment of torsion that screw rod rotates.

Example 2～5

Below the catalyzer and the temperature of reaction of different EG and PDO ratio are tabulated, other processes are similar to example 1.

Table 1

	EG/PDO	Esterification Stage		Polycondensation phase
		Esterification Stage		Polycondensation phase				Tetrabutyl titanate (ppm/g TPA)	Temperature of reaction (℃)	Tetrabutyl titanate (ppm/g TPA)	Zinc acetate (ppm/g TPA)	Trimethyl phosphite 99 (ppm/g TPA)	Temperature of reaction (℃)
		Example 2	2/8	80	240	160	80	Tetrabutyl titanate (ppm/g TPA)	Temperature of reaction (℃)	Tetrabutyl titanate (ppm/g TPA)	Zinc acetate (ppm/g TPA)	Trimethyl phosphite 99 (ppm/g TPA)	Temperature of reaction (℃)	100	270
Example 3	4/6	Example 2	2/8	80	240	160	80	60	240	120	160	100	275	100	270
Example 3	4/6	Example 4	6/4	40	250	80	240	60	240	120	160	100	275	100	285
Example 5	8/2	Example 4	6/4	40	250	80	240	20	250	40	320	100	290	100	285

Table 2

	Limiting viscosity (dL/g)	Content of carboxyl end group (mol/t)
	Limiting viscosity (dL/g)	Content of carboxyl end group (mol/t)	Example 1	0.667	16
Example 2	0.696	20	Example 1	0.667	16
Example 2	0.696	20	Example 3	0.734	19
Example 4	0.792	34	Example 3	0.734	19
Example 4	0.792	34	Example 5	0.801	21

。

Claims

1. the preparation method of a copolyesters PET/PTT is characterized in that this method comprises the steps:

1) TPA and PDO, EG carry out esterification: its molar ratio is TPA/ (PDO+EG)=1: 1.4, temperature of reaction is 240-250 ℃, the fractional column column top temperature is 80-120 ℃, and reaction was carried out 3-4 hour, and whether the amount of water generation reaction is weighed and reacted completely;

2) esterification reaction product carries out prepolymerization reaction: temperature of reaction is 260-270 ℃, reacts 20-40 minute;

2. preparation method according to claim 1 is characterized in that driving oxygen away with high purity nitrogen bubbling before esterification feeds intake.

3. preparation method according to claim 1 is characterized in that in the described esterification, adds tetrabutyl titanate, and its amount ranges is 10～100ppm/gTPA.

4. preparation method according to claim 1 is characterized in that in the described polycondensation, adds tetrabutyl titanate, zinc acetate and trimethyl phosphite 99; Wherein the total content of tetrabutyl titanate and zinc acetate is 150～400ppm/gTPA, and the consumption of trimethyl phosphite 99 is 50～150ppm/gTPA.