CN1187413A

CN1187413A - Improved process for production of polyester resins

Info

Publication number: CN1187413A
Application number: CN97117432A
Authority: CN
Inventors: H·阿尔加塔
Original assignee: Sinco Engineering SpA
Current assignee: Sinco Engineering SpA
Priority date: 1996-08-01
Filing date: 1997-07-31
Publication date: 1998-07-15

Abstract

Process for the crystallization of aromatic polyester resins having intrinsic viscosity between 0.5 and 0.7 dl/g wherein the resin is extruded in the form of a strand at extruder exit or the chips obtained by cutting the strand are crystallized maintaining them at temperature between 160 DEG C and 220 DEG C for sufficient time to obtain a crystallized product wherein the DSC curves do not show the presence of practically any premelt peaks.

Description

The method of improved production mylar

The present invention relates to a kind of method of improved production aromatic polyester resin.

Aromatic polyester resin can require HMW (corresponding inherent viscosity (IV) uses in generally greater than 0.65～0.75dl/g) operation similar such as the application of molding, extrusion molding, injection moulding neutralization.

Otherwise it is low with the resin IV value of system fiber to be used to make film.Between 0.65～0.70dl/g.

The preparation of resin is to adopt aromatic dicarboxylic acid, and normally the polycondensation reaction of terephthalic acids or its alkyl diester and aliphatic diol is carried out, and operates under the condition for the temperature of the resin that obtains the about 0.4～0.7dl/g of final IV value and pressure.

The resin that is used for molding and similar operations carries out polycondensation and handles (SSP) solid-state, and purpose is that IV is increased to desirable numerical value.

Before SSP handled, resin carries out crystallization under the condition that can obtain sufficiently high degree of crystallinity (35～40%) handled, and does not occur in the defective that can cause the particle adhesion of equipment downtime under the harsh conditions in the SSP treatment step so that make.

This crystallization is handled and is carried out in fluidized-bed reactor or similar preparation, and polymer is heated to about 160 ℃～220 ℃.

The SSP treatment temperature is usually between 180 ℃ and 220 ℃; Because the particle adhesion phenomenon that the polymer imperfect crystalization causes, high temperature can improve the kinetic energy of polycondensation reaction significantly.High temperature can not adopt in practice.

The crystallization speed of known mylar with higher inherent viscosity (greater than 0.5%dl/g) is well below the crystallization speed of low IV value (being lower than 0.4dl/g) resin.Also knownly can obtain the crystalline resins that the pre-fusion peak does not appear in its DSC curve by the low IV value resin crystallization that makes fusion.

Found unexpectedly at present by IV value greater than 0.4 and generally the molten resin crystallization between 0.55～0.7dl/g can obtain the resin that the pre-fusion peak does not appear in the DSC curve with crystalline structure, perhaps if the pre-fusion peak, their melting enthalpy is lower than 5J/g.

The result who points out above obtains by the form that resin is extruded into the bar thigh, the outlet of extruder place make these thighs between 150 ℃～220 ℃ crystallization and be incubated the sufficiently long time so as to obtain desired degree of crystallinity and above pointed crystalline structure.

If consider by the IV value can not obtain to have the crystalline resins that does not in fact occur the DSC curve at pre-fusion peak accordingly greater than the mylar of 0.55dl/g from the molten state cool to room temperature and then with the crystallisation procedure does that temperature is increased to the temperature (150 ℃～220 ℃) that is suitable for crystallization, the results were quite startling for this.

In the Polyethylene Terephthalates's (PET) who obtains according to the inventive method situation, the temperature at the pre-fusion peak is about 260 ℃～262 ℃ and the pre-fusion peak in fact do not occur.

The crystallization PET of Huo Deing can adopt than the high a lot of temperature of the common temperature that adopts of conventional junction crystallization method in next step SSP stage and handle like this.Thereby the time that SSP handles reduces significantly.

The crystallization of the polymer that carries out according to method of the present invention is handled, and not only can obtain to have the polymer of sufficient crystallising tissue, and simplify the preparation technology of this resin significantly.

In fact unnecessaryly polymer is cooled to room temperature and then pelletizing is heated to crystallized temperature in order to carry out granulation.

The inherent viscosity of mylar of carrying out method of the present invention is usually greater than 0.55dl/g and between 0.55～0.70dl/g.The dianhydride that in the past added a kind of tetrabasic carboxylic acid in this resin, preferred aromatics, for example 1,2,4,5-benzenetetracarboxylic acid dianhydride, its consumption are 0.01～2% weight.

Preferred 170 ℃～200 ℃ of crystallized temperature, crystallization time is 5～30 minutes.

The crystalline resins that adopts method of the present invention to obtain is being higher than 160 ℃ temperature and is generally carrying out enough polycondensation for a long time at 170 ℃～230 ℃ and handle to obtain the raising of desired inherent viscosity solid-state.

The SSP of the crystallisation procedure does of this resin and this follow-up resin handles and can carry out continuously.To remain on the temperature that is suitable for crystallization from the firm bar thigh that comes out of extruder and be cut into graininess then, and when remaining heat, these pelletizings just they are delivered to the SSP stage, or the bar thigh from extruder firm when coming out still to be in the temperature of crystallization temperature and Geng Gao by pelletizing, then will deliver to the SSP stage after these pelletizing crystallizations again.Preferably make after the temperature heat-set treatment of these pelletizings between 160～200 ℃ 10～60 minutes, under still crystallized temperature or lower a little temperature (5～20 ℃), deliver to the SSP stage.

Crystallization stage and the pelletizing of bar thigh are carried out under inert gas atmosphere, for example use the nitrogen from the circulation in SSP stage, because this nitrogen temperature is enough high, can use its heat to be used for the heating of crystallization stage.

The mylar that uses method of the present invention is to pass through aromatic dicarboxylic acid, and---terephthalic acids and its dialkyl group diester for example ethylene glycol, butanediol, 1 of terephthalic acids dimethyl ester---with the glycol that has 1～10 carbon atom---for example preferably, 4-cyclohexanedimethanol---in accordance with known methods polycondensation reaction obtains.

Preferred resin is Polyethylene Terephthalates and its ethylene terephthalate copolymer (unit that maximum approximately 15% terephthalic acids are derived among the latter is replaced by isophthalic acid and/or naphthalene dicarboxylic acids derived units), and poly-terephthalic acids butanediol ester, poly-naphthoic acid alkylene ester and their copolymer.

The resin that obtains with method of the present invention is applied in the preparation of the molded article of other technology that adopts known injection moulding, blowing, extrusion molding and notes-blow molding, thermoforming technology or use in the plastic material field.

Do not carry out the resin that is higher than 0.5dl/g (generally between 0.5～0.7dl/g) that SSP handles, their DSC curve shows and do not have the pre-fusion peak, if or exist, its melting enthalpy is a new product less than 5J/g.

Embodiment given below specifies of the present invention but does not limit the present invention.

Inherent viscosity is according to ASTM 4603-86, with the 0.5g polymer in the mixed solution of 100ml 60/40 (weight) phenol and tetrachloroethanes 25 ℃ of measurements.

The DSC curve is surveyed and drawn with 10 ℃/minute firing rate.

Embodiment 1

Be extruded from the PET of the IV=0.60dl/g of molten state polycondensation phase and form the bar thigh, the bar thigh is in 185 ℃ at outlet of extruder and keeps pelletizings then in 10 minutes in nitrogen atmosphere.

So the DSC curve (Fig. 1) of the pelletizing that obtains is presented at 216 ℃ a peak, at 173 ℃ a little pre-fusion peak is arranged, and its Δ H is 1.991J/g.

Then these pelletizings are packed into and carry out the solid state condensation reaction in the reactor that is heated to 230 ℃, and keep the sufficiently long time to reach desired viscosity value added in this temperature.

Embodiment 2

The technology identical as embodiment 1, difference are to use the COPET that contains 2% isophthalic acid unit.

There is not the pre-fusion peak in the DSC curve of the polymer that is obtained.

Embodiment 3

The technology identical as embodiment 2, difference are that the bar thigh kept 20 minutes at 180 ℃.The DSC curve of the polymer that obtains is shown among Fig. 2.

Embodiment 4

The technology identical as embodiment 1, difference are that the bar thigh kept 20 minutes at 175 ℃.

The DSC curve is shown among Fig. 3.

Claims

1, inherent viscosity comprises the steps: greater than the method for the crystallization processing of the mylar of 0.5dl/g

-this molten resin extruded be strand shape;

-these are kept the necessary time at the bar thigh at outlet of extruder place or by cutting pelletizing that these thighs obtain 150 ℃～220 ℃ temperature, in order to obtain the resin of crystallization, the DSC curve of this resin shows and do not have the pre-fusion peak, if or exist, its melting enthalpy is less than 5J/g.

2, the mylar of crystallization before solid state condensation is handled, has the inherent viscosity greater than 0.5dl/g, and its DSC curve shows and do not have the pre-fusion peak, if or exist, its melting enthalpy is less than 5J/g.

3, according to the mylar of claim 2, wherein said resin is selected from the Polyethylene Terephthalates, contains the copolymerization of maximum 20% mole of isophthalic acid and/or naphthalene dicarboxylic acids derived units to diacid glycol ester and poly-terephthalic acids butanediol ester.

4, the mylar that method obtained that adopts claim 1 to describe.

5,, be selected from the Polyethylene Terephthalates, contain the copolymerization ethylene terephthalate of maximum 20% mole of isophthalic acid and/or naphthalene dicarboxylic acids derived units according to the mylar of claim 4.

6, the preparation method of the mylar between 0.55～0.70dl/g, wherein said resin carries out crystallization according to the method for claim 1 to be handled, and carries out polycondensation and handles solid-state then.

7, according to the method for claim 6, the pelletizing of wherein said crystallization after the heat-set treatment of the temperature between 160 ℃～200 ℃, is carried out solid state condensation and is handled when they still are in crystallized temperature or low a little some temperature.

8, according to the method for claim 7, wherein said resin is selected from the Polyethylene Terephthalates, contains the copolymerization ethylene terephthalate and the poly-terephthalic acids butanediol ester of maximum 20% mole of isophthalic acid and/or naphthalene dicarboxylic acids derived units.

9, according to the method for claim 6 or 7, wherein said resin has added a kind of tetracarboxylic dianhydride of 0.05～2% weight.

10, according to the method for claim 9, wherein said dianhydride is 1,2,4,5-benzenetetracarboxylic acid dianhydride.