CN1073582C - Method of synthesis for biodegradable copolyester - Google Patents

Abstract

The present invention relates to a method for synthesizing biodegradability copolyester by a one-step method, particularly to a method for synthesizing PET/PCL copolyester (PETCL). The one-step method comprises: bis-2-hydroxyethyl tere-phthalate and epsilon-hexanolactone (epsilon-CL) are used as raw materials, and tetrabutyl titanate is used as a catalyst; the raw materials and the catalyst respectively react for 0.5 to 5.0 hours at 160 to 220 DEG C and for 0.5 to 8.0 hours at 230 to 270 DEG C under 6.66*10<-6> to 2.66*10<-4> MPa to prepare the biodegradability copolyester. The synthetic method has the advantages of simple polymerization technology, polymerization process contraction, reaction equipment reduction, easy control of polymerization reactions and stable product composition and performance, which is favourable for the realization of industrial production.

Description

A kind of synthetic method of biodegradable copolyester

The present invention relates to a kind of synthetic method of biodegradable copolyester, specially refer to the method for the synthetic poly terephthalic acid binaryglycol ester (PET) of a kind of employing single stage method/polycaprolactone (PCL) copolyesters (PETCL).

Since this century, the '30s polymer science was established, high molecular synthetic material was just developed rapidly along with the petrochemical industry progress, had realized scale operation to the sixties.Because in light weight, advantages such as intensity big, easy machine-shaping that high molecular synthetic material possesses are so be widely applied to every field such as industry, agricultural, national defence, communications and transportation, building, food, clothes and medicine.Macromolecular material has become indispensable integral part in the human society life at present, and progressively substituted metal becomes centurial main raw down.Yet because a large amount of uses of high molecular synthetic material, the problem of environmental pollution of Chan Shenging is also realized by people gradually therefrom.Degradation speed is slow because most of synthesized polymer materials all have satisfactory stability under the nature condition, and a large amount of wastes remains in public place, arable land or the ocean, and the physical environment of depending on for existence to the mankind has caused serious pollution.Therefore how to reduce and prevent that this pollution from having become an important topic of scientific circles.Since the seventies, developed multiplely in the world at the degradable macromolecular material of nature, become one of main method that solves these serious problems.Thus, some country has also stipulated the product scope of necessary use Biodegradable polymer material with the form of rules.So in today and future that environmental issue becomes more and more outstanding, developing the novel degradable type macromolecular materials with excellent properties will be a very important and urgent task for human society more.

In ecology or internal milieu, can be called Biodegradable polymer material owing to the macromolecular material that biology or body fluid erosion, metabolism are degraded.Usually this is meant the material that has the obvious degradation behavior to take place between its usage period.The biodegradable macromolecular material by sources can be divided into chemosynthesis polymer, biotechnology synthetic macromolecule and natural polymer, in addition because by having biological disintegrating property with the natural polymer blended synthetic macromolecule that does not possess biodegradability originally that also can make such as starch, the biological disintegration product of plastics such as therefore existing polyethylene, polystyrene, polymeric amide, polyvinyl acetate (PVA), ABS by adding starch conversion.

Poly terephthalic acid binaryglycol ester (PET) have intensity height, hardness big, be difficult for good performance characteristics such as degradation with aging, therefore except important materials such as conduct weaving, electrical equipment, building materials, packing, also be widely used in preparing the bigger medical products such as artificial organ of artificial blood vessel, operating sutures and volume.Yet can not degrade at nature because the amylose regularity of PET is big, degree of crystallinity is high, become one of primary pollution source that causes environmental pollution.So PET is carried out modification, makes it have the important subject that biodegradability is current high molecular scholar.

Polycaprolactone (PCL) is the aliphatic polyester that a class has biological degradability, and it can be hydrolyzed and microbiological deterioration, so can make it to give biological disintegrating property with polymer blend such as PET.Research to the copolymer p ETCL of PET and PCL has English Patent 1,076,887, at Zn (OAc) ₂, Sb ₂O ₃, Ca (OAc) ₂, MeOLi, (PrO) ₄Dimethyl terephthalate (DMT) (DMF) and ethylene glycol (EG) reaction before this under the saline catalyst effects such as Ti, the back adds the method preparation that caprolactone (CL) carries out polycondensation, but reacts not exclusively, and big content of starting materials unreacted is arranged.It is the preparation method of raw material pyroreaction that Japanese patent laid-open 3-6258 has proposed with PET and monomer ε-CL; Te Kaiping 2-252729 has proposed the technology that the continuously feeding preparation contains the PETCL of PET section more (PET 80mol%), and the color and luster of polymkeric substance is better; Te Kaiping 3-263425 has proposed with Ti (OBu) ₄Make the method for ε-CL open loop and PET copolymerization for catalyzer; Te Kaiping 4-72325 has then proposed the method for directly at high temperature synthesizing PETCL with PCL and PCL reaction.The something in common of these methods all is to come synthetic by two steps, promptly at first prepare homopolymer (PCL or PET), and then with a kind of homopolymer and another kind of monomer (BHET or ε-CL) carry out pyrocondensation, or with two kinds of homopolymer (PCL and PET) at high temperature transesterification reaction make copolyesters.The shortcoming of these class methods is to synthesize homopolymer, needs to consume the more time and the energy; In addition, high molecular weight reactive both had been difficult for evenly, also was difficult to control.

The present invention has overcome the shortcoming that adopts polymerization technique complexity, product lack of homogeneity in the synthetic PETCL copolyesters of two methods in the prior art, and provide a kind of shorten polymerization flow process, technology simple, with the method for the synthetic PETCL copolyesters of single stage method.

The present invention adopts bishydroxyethyl terephthalate (BHET) and 6-caprolactone, and (ε-CL) be raw material, wherein BHET and ε-CL are 90: 10～10: 90 in molar ratio, with Ti (OBu) ₄Be catalyzer, catalyst levels is 1～100/10000wt% of BHET.

The method of one-step synthesis PET/PCL copolyesters of the present invention (PETCL), step is carried out in the following order:

1. be that adding in 90: 10～10: 90 is equipped with in the reactor of agitator, airway and water distilling apparatus in molar ratio with BHBT and ε-CL, add catalyzer metatitanic acid four butyl esters [Ti (OBu) ₄];

2. reacted 0.5-5.0 hour for 160～220 ℃ at normal pressure under nitrogen protection, preferred temperature is 190～210 ℃, is warmed up to 230～270 ℃, reduces pressure 6.66 * 10 ^-6MPa～2.66 * 10 ^-4MPa, preferable pressure are 1.33 * 10 ^-5MPa～1.33 * 10 ^-4MPa reacted 0.5～8.0 hour again, productive rate 90～99%.Above-mentioned BHET can adopt industrial BHET.

The present invention adopt the synthetic PETCL copolyesters of single stage method have simplification polymerization technique, shortened the polymerization flow process, reduced conversion unit, and make that polyreaction is easy to control, the composition and performance of product is stable, help realizing suitability for industrialized production, have following characteristics simultaneously: the 1.PETCL multipolymer can be at Ti (OBu) ₄Katalysis under, the method by BHET and ε-CL direct copolymerization is synthetic.Industry BHET raw material also can successfully generate copolymer p ETCL; 2. the composition of copolyesters can be controlled by the method for conditioned reaction thing feed ratio; 3. copolymer p ETCL is a thermoplastic elastomer; 4. the wetting ability of multipolymer increases along with the increase of PCL component; 5.PETCL composition with degradation speed substantial connection is arranged, the PCL component concentration is high more, copolymer degradation speed is fast more; 6. along with the degraded of copolyesters PETCL, the mechanical property of material significantly decreases, so PETCL is a kind of well behaved degradability macromolecular material, can reduce the PET pollution on the environment; 7. copolyesters PETCL is a kind of novel biological degradability superpolymer, biodegradation rate difference under the effect of different bacterium.

Example 1. adds reaction ax that agitator, airway and water distilling apparatus be housed with BHET with 40: 60 mol ratios with 15.0 gram ε-CL, is incorporated as the butyl (tetra) titanate of BHET weight 5/10000 then.System is passed to nitrogen,, system is warmed up to 250 ℃ again, 1.33 * 10 200 ℃ of reactions 2 hours ^-4Air pressure reacted 2 hours down in the MPa, discharging while hot under nitrogen protection.

The purification process of copolyesters is after polymkeric substance is made into 5% chloroformic solution, under agitation slowly to be added drop-wise to redeposition in the industrial alcohol (volume ratio 1: 10), and drying under reduced pressure 24 hours at room temperature places exsiccator to preserve then.

The intrinsic viscosity of copolyesters adopts one point method to measure.After sample ligand being made the chloroformic solution of 0.5g/dl, use dark type viscometer in the relative viscosity η of 30 ℃ of specimen _r, be calculated as follows again: $\&lsqb;\mathrm{\&eta;}\&rsqb;=\sqrt{2({\mathrm{\&eta;}}_{\mathrm{sp}}-\ln {\mathrm{\&eta;}}_r)}/C$ In the formula: [η]-intrinsic viscosity (d1/g) η _r-relative viscosity

η _Sp[η]=1.34 of copolyesters behind-specific viscosity C-sample concentration (g/dl) purifying, actual ratio of components is BHET: ε-CL=50.0: 50.0 (mol%).The stretch breaking strength of sample is 45.1MPa, and extension at break is 1430%.

The palliating degradation degree (45 ℃, 4 weeks) of copolyesters sample under difference degraded environment

	Before the degraded	Degraded is pH5.0 pH9.0 0.1NNaOH 0.1NHCL during 4 weeks
			Mn(×10 -4)	13.4	11.8 12.2 10.8 9.5
[η](dl/g)	1.34	0.97 0.97 0.98 0.82

The degraded situation (28 ℃, t=15 days) of copolyesters sample under different fungi effects

Fungi name molecular weight (* 10 -4) molecular weight and molecular weight (%)
	Hypocrea, (meat seat Pseudomonas) 11.8 11.9 Fasarium, (Fusarium) 12.0 10.0 Polyoporus, (Polyporus) 12.2 9.0 Tiametes, (trametes) 12.5 6.7 Marasmius, (Agaricus) 13.0 3.0

Example 2: reacting and purifying with example 1 the same terms, but feed ratio BHET: ε-CL=50: 50 (mol%), [η]=0.97 of gained copolyesters, actual ratio of components BHET: ε-CL=55.8: 44.2 (mol%).The stretch breaking strength of sample is 46.1MPa, and extension at break is 1350%.Example 3: to react and purifying with example 1 the same terms, that still feed intake is industry byproduct BHET, reacts [η]=0.84 of gained copolyesters 3.0 hours.Example 4: reacting and purifying with example 1 the same terms, but feed ratio BHET: ε-CL=66.7: 33.3 (mol%), [η]=0.96 of gained copolyesters, actual ratio of components BHET: ε-CL=73.1: 26.9 (mol%).Example 5,6,7: reacting and purifying with example 1 the same terms, but the synthesis under normal pressure phase temperature is respectively 160,200 and 240 ℃ in the copolyesters building-up process, and the reaction times is 4 hours, and [η] of gained copolyesters is respectively 1.16,1.38 and 1.54.Example 8,9,10: reacting and purifying with example 1 the same terms, but catalyst levels is respectively 1/10000wt%, 5/10000wt% and 10/10000wt%, and [η] of gained copolyesters is respectively 1.24,1.31 and 1.38.

Claims (3)

1, a kind of synthetic method of biodegradable copolyester is characterized in that described synthetic method is to adopt single stage method, and step is carried out in the following order:

(1) be that 90: 10～10: 90 and butyl (tetra) titanate add in the reactor in molar ratio with industrial goods bishydroxyethyl terephthalate and 6-caprolactone, the butyl (tetra) titanate consumption is 1～100/10000wt%;

(2) under nitrogen protection, reacted 0.5～5 hour for 160～220 ℃ at normal pressure;

(3) be warmed up to 230～270 ℃, in decompression 6.66 * 10 ^-6MPa～2.66 * 10 ^-4Under the MPa, reacted productive rate 90～99% again 0.5～8.0 hour.

2, the synthetic method of a kind of biodegradable copolyester according to claim 1 is characterized in that described temperature is 190～210 ℃.

3, the synthetic method of a kind of biodegradable copolyester according to claim 1 is characterized in that described pressure is 1.33 * 10 ^-5MPa～1.33 * 10 ^-4MPa.