CN1159462A - Legradable thermoplastics from lactides - Google Patents

Abstract

The present invention relates to a plasticizer polymer for lactide and its mixture. They can be made into various biodegradable products which possess the characteristics of conventional plastics and can be substituted for them. Moreover, it also relates to a material which can be used as a substitute for crystalline polystyrene and its preparation method. Besides, it also relates to a blending process of conventional thermoplastic plastics and polylactic acid to prepare a new-type packing material, and relates to a blending process of compatible elastomer and polylactide so as to obtain a modified polylactide with resistance to shock.

Description

Biodegradable composition and method of making the same

First embodiment of the present invention is about L-rac-Lactide, D-rac-Lactide, D, and the plasticized polymer of L-rac-Lactide and composition thereof, this polymkeric substance are suitable for being used for preparing the wrapping material that prepared by nondegradation plastics (as polyethylene) usually; Also relate to and prepare flexible film and the method for other wrapping material and exclusive goods thereof.The present invention can be used to prepare biodegradable goods, and these goods also have the feature of conventional plastics simultaneously.

Second embodiment of the present invention is about a kind of material and preparation method thereof, and this material can be used as the surrogate of crystal polystyrene (be also referred to as sometimes and can be orientated polystyrene or OPS).This material is the indemnity of OPS, by forming at biodegradable polyester in about 1 year internal environment.The polyester that this material is made up of polymeric lactic acid, by D-lactic acid or L-lactic acid and D, the preparation of L-lactic acid.Definite physicals is determined by ratio, processing mode and some auxiliary (in some cases) of above-mentioned two kinds of polymeric monomeric units, so that satisfied needs as the OPS surrogate.For example, as L-lactic acid/D, the ratio of L-lactic acid is approximately at 90/10 o'clock, and the lactic acid polymer of gained (PLA) is a kind of good thermoplastic plastics, transparent, colourless and very stiffening, be very suitable for being used for preparing film, foam materials and other thermoformed articles of disposable (one way) plastics.After PLA used as packing plastics, slowly biological degradation was harmless material in environment.This harmless processing can relax serious day by day plastic pollution problem of environment.

Third embodiment of the invention relates to conventional thermoplastics and polylactic acid blend.This provides the novel thermoplastics that can degrade in environment.This thermoplastics that can degrade in environment can be applicable to many fields.Also relate to the method for preparing flexible film and other wrapping material, the goods that it is exclusive.The present invention can be used to prepare to degrade in environment possesses the goods of conventional plastic features simultaneously again.

The 4th embodiment of the present invention relates to compatible elastomerics and polylactide blend.This provides impact-resistant modified polylactide, and this polylactide can be applicable to many fields, comprises those fields of using impact-resistant modified polystyrene.Also relate to the method for preparing wrapping material and exclusive goods thereof.The present invention can be used to prepare the goods that can degrade and possess conventional impact resistant plastics feature in environment.

Because a large amount of depleted Plastic Packaging Materialss cause environmental problem, thus need can be in environment biodegradable thermoplastics wrapping material.In the U.S., the plastics sales volume was 24,400,000,000 kilograms in 1987, and wherein 57.7 hundred million kilograms are listed in Plastic Packaging Materials.A large amount of plastics go out of use, and become the plastic pollution source, their not only big stop-tendency scapes, but also threatening halobiontic life.Estimate therefore annual and dead seabird number up to 1,000,000 of 1-2, mammiferous mortality is given birth to up to 100000 in the sea.

Another problem relevant with handling Plastic Packaging Materials is that refuse landfill is also dwindled day by day.The existing garbage loading embeading place that is used to handle solid waste of most of main cities of the early 1990s will run out according to estimates.The solid waste that generally contains 3% (weight) or 6% (volume) in the Plastic wastes approximately.

Another shortcoming of conventional plastics is that they by the oil preparation, therefore will be subjected to the instable restriction of foreign crude oil import after all.Raw material should derive from reproducible domestic source preferably.

Yet, have sufficient reason to use wrapping material.The beautiful packing that the specified quantitative product is housed that can process rapidly can produce a kind of moving aesthetic feeling.These packings can keep clean and package stability, also have other required performance, as so that the transparency of observed content thing.These known package material produce costs are low, the chemical stability height.Yet this just stability makes these plastics have the very long life-span, so that after disposable the finishing using, depleted be packaged in the environment will be difficult to calculate long-time in existence.

Known lactic acid polymer and multipolymer are a sharp unique material in some cases, because they can biological degradation, have biocompatibility, and are thermoplastic.These polymkeric substance are good thermoplastic plastics, and they in animal body can be in several months absolutely biological degradation to the year by hydrolysis.They begin to demonstrate signs of degradation after several weeks in wet environment, be placed in soil or the seawater, can disappear about 1 year.Degraded product is lactic acid, carbonic acid gas and water, and these products all are harmless.

Be actually lactic acid is converted into the cyclisation lactide dimer, rac-Lactide is the monomer of polyreaction.Lactic acid can obtain by the double valency raw material of fermented maize starch or maize treacle and so on, also can be from the petroleum chemistry feedstock production of ethene and so on.Lactide monomer normally is converted into resin by catalytic fusion polymerization (a kind of universal methods of known preparation plastics).By carrying out polymerization with the intermediate monomer, above-mentioned resinous principle can change to some extent.Molecular weight is easy to control.Can change and form so that obtain special performances.

The homopolymer and the multipolymer of various cyclic esters (as glycollide, rac-Lactide and lactone) are disclosed in many patent documentations and publication.The high-molecular weight polymer that the method for the early stage disclosed polymerization lactic acid of patent documentation, rac-Lactide or both mixtures can not obtain having good physical behavior.The goods of these polymkeric substance often are the adhesive materials that is clamminess, and physicals is bad.Referring to US1995970, US2362511 and US2683136.US2668162 proposes to use pure glycollide and rac-Lactide to prepare high molecular lactide homopolymers and multipolymer first.Rac-Lactide is the dilactone of lactic acid.When forming rac-Lactide, discharge water byproduct.Rac-Lactide can ring-opening polymerization be the high molecular linear polyesters, need not complicated polycondensation method.Compare with homopolymer, the multipolymer of rac-Lactide and glycollide can improve toughness and thermoplasticity processing characteristics.Adopt intermediate lactide can make PLA homopolymer and multipolymer with superior physical properties.US2668162 discloses the multipolymer of rac-Lactide and glycollide, and this multipolymer is a toughness and transparent, can be cold drawn, but drawing-off can form self-supporting films in 210 ℃.

The homopolymerization and the multipolymer method of rac-Lactide are also disclosed at this patent and other document, tough in order to prepare, can be orientated, stiffening crystalline polymer, this multipolymer can be processed into have the physiologically acceptable biodegradable fiber and the alternative of (be sometimes referred to as and can absorb).These polymkeric substance slowly disappear by hydrolytic action.Referring to U.S. Patent number 2703316,2785987,3297033,3463158,3531561,3620218,3636956,3736646,3797499,3839297,3982543,4243775,4438253,4496446; European patent application 0146398; International Patent Application WO 86/00533 and Offenlegundsschrift 2118127.

Some other patent proposes these polymkeric substance are used for toughness surgical operation element, as biomedical fastening piece, screw, drift bolt, nail, hone lamella etc.Referring to US3739773, US4060089 and US4279249.

Utilize the sustained release device of the mixture preparation of biologically active substance and rac-Lactide and/or glycollide homopolymer and multipolymer to disclose already.Referring to U.S. Patent number 3773919,3887699,4273920,4419340,4471077,4578384,4728721; EnvironmentalScience and Technology, 7 (10), 955 (1973); The 5th international biologically active substance sustained release discussion, minutes (R.G.Sinclair, 5.12 and 8.2, Universityof Akron Press, 1978.).These application need toughness or vitreous materials of lactide polymer and multipolymer, this material be can polish and do not demonstrate as the required physicals of thermoplastic package material.

The some application of lactide copolymer as wrapping material are disclosed in the prior art.For example, the transparent self-supporting film among the above-mentioned patent US2668162 is by rac-Lactide and glycolide copolymer preparation.In US2703316, with the orientable lactide polymer of toughness as the film forming precursor.Disclose a kind of pliable and tough, strong, matter is crisp or softish " wrapping paper ".Yet, must use the wetting polylactide of volatile solvent for obtaining kindliness, otherwise can only obtain hard and crisp polymkeric substance.The fusing point that requires lactide monomer is greater than 120 ℃.L-lactide monomer fusing point is 95 ℃, D, and L-rac-Lactide fusing point is 128 ℃.This be in the prior art modification lactide polymer to obtain the specific examples of kindliness.In US3021309, with rac-Lactide and δ-Wu Neizhi and caprolactone copolymerization, so that the modification lactide polymer obtains the flexible white crystalline solid.Wherein only mention and contain caprolactone and 2, the flexible solid copolymer compositions of the multipolymer of 4-dimethyl-4-methoxyl methyl-5-hydroxyl valerolactone does not obtain the composition of rac-Lactide.US3284417 relates to the method for preparing polyester, and this polyester can be used as the intermediate of softening agent and preparation elastomerics and foams.This patent does not adopt rac-Lactide, but uses the composition based on 7-9 membered ring lactone (as 6-caprolactone) to obtain required intermediate.Do not provide tensile strength, modulus and elongation rate data.US3297033 proposes to prepare opaque material with glycollide and glycolide-lactide copolymer, can be made into after this opaque material orientation and is suitable for use as sutural fiber.Wherein write " softening agent hinders crystallization, but can be used for cavernous body and film ".In these disclosures, can obviously see, unless carry out plasticising, above-mentioned lactide homopolymer and multipolymer are crisp hard.US3736646 also is this situation, and wherein rac-Lactide-glycolide copolymer is that solvent with methylene dichloride, dimethylbenzene or toluene and so on softens.In US3797499, point out, L-rac-Lactide and D, the L-lactide copolymer has bigger snappiness, can be used for drawing the fiber as absorbable suture.This fibre strength is greater than 50000psi, and elongation is about 20%, and modulus is about 1000000psi.Compare with the most flexible wrapping material composition, it is quite crisp hard that these fibers remain, and this is relevant as sutural purposes with it.US3844987 discloses and has utilized biodegradable polymers and exist the blend and the graftomer of biodegradable product (as cellulose materials, soyflour, husk, brew-house's saleratus) to prepare some goods naturally, as is used for splendid attire and promotes seed or seedling to germinate and the container of the medium of growing.These goods are unsuitable for as wrapping material.

US4620999 discloses a kind of composition for preparing biodegradable disposable plastic bag, and it contains 3-hydroxybutyric acid polymkeric substance and 3-hydroxybutyric acid/3-hydroxyl pentanoate copolymer.Lactic acid is 2 hydroxy propanoic acid as you know.US3982543 proposes as softening agent lactide copolymer to be carried out plasticising with volatile solvent, to obtain kindliness.US4045418 and US4057537 are by with caprolactone and rac-Lactide (L-rac-Lactide or D, L-lactide) copolymerization and obtain kindliness.US4052988 utilizes poly-(to-diethyleno dioxide ketones) (kink of poly (p-dioxanone) preparation absorbable suture and kink insurance.US4387769 and US4526695 only disclose at the just submissiveer rac-Lactide of higher temperature and the polymkeric substance and the multipolymer of glycollide.European patent 0108933 adopts and obtains a kind of ternary block polymer by poly ethyldiol modified glycolide copolymer, it is said to can be used as suture material.As mentioned above, any is arranged is consistent, promptly has only the fugitive volatile solvent softening agent of employing or other comonomer just can make lactide polymer have kindliness.

L-rac-Lactide and D, the multipolymer of L-rac-Lactide are known in the prior art, are not the intrinsic physical properties but the document of quoting shows kindliness.US2758987 discloses L-rac-Lactide or D, and the homopolymer of L-rac-Lactide allegedly can fusion be pressed into transparent tough alignment films.The performance of poly-L-propyl ester is as follows: tensile strength 29000psi, elongation 23%, tensile modulus 710000psi.Poly-D, the performance of L-rac-Lactide is: tensile strength 26000psi, elongation 48%, tensile modulus 260000psi.50/50 L-rac-Lactide and D weight ratio are only disclosed are, the multipolymer of L-rac-Lactide, i.e. L-lactic acid and D, the multipolymer of L-lactic acid.Only provided sticky point character (example 3).It is said and adopt a kind of enantiomorph monomer (as optically active L-rac-Lactide) to help obtaining high strength.US2951828 has introduced L-rac-Lactide and D, and L-lactide homopolymers and weight ratio are L-rac-Lactide/D of 75/25,50/50 and 25/75, and the L-lactide copolymer wherein discloses the bead polymerization of alpha-hydroxy carboxylic acid compounds.The softening temperature of gained multipolymer is 110-135 ℃.Do not provide the data relevant, just provided the data of relevant bead size and softening temperature with hardness and kindliness.In US3636956 and US3797499, mentioned weight ratio and be 95/5,92.5/7.5, L-rac-Lactide/D of 90/10 and 85/15, the L-lactide copolymer.Estimate the performance of its drawn fiber long filament, its tensile strength is greater than 50000psi, and modulus is about 1000000psi, and elongation is about 20%.The same with above-mentioned US3636956, improve flexible with softening agent.Offenlegundsschrift2118127 discloses a kind of obvious crystalline polymkeric substance of snowy white, comprises 90/10 L-rac-Lactide/D, the L-lactide copolymer.But do not provide the physicals of this multipolymer.This patent points out that described material can be used for surgical device.

US3297033,3463158,3531561,3636956,3736646,3739773 and 3797499 discloses lactide polymer and multipolymer, and they are the be orientated polymkeric substance that are applicable to the strong crystallization tendency of having of fiber and suture material.The material of high-crystallinities is used in these disclosure introductions, with this kind material orientation, obtains tensile strength and modulus respectively greater than the oriented material of 50000psi and 1000000psi by drawing-off and annealing.Can be molded as various moulded products though mention, not mention the physicals of non-oriented extrudate and moulded work.For example, US3636956 discloses preparation 90/10 (weight) L-rac-Lactide/D, L-rac-Lactide, and the method for draw orientation fiber.Yet above-mentioned document proposes preferably to adopt pure L-lactide monomer, so that improve the intensity of degree of crystallinity and drawn fiber.

US3797499 discloses a kind of 95/5 (weight) L-rac-Lactide/D, the multipolymer of L-rac-Lactide (routine V), however this material is used for preparing long filament.The performance that provides at the 5th hurdle the 1st row is not so good as respective performances of the present invention, has wherein adopted the softening agent of triacetin, ethyl benzoate and diethyl phthalate and so on.

US3736646,3773919,3887699,4273920,4471077 and 4578384 discloses the matrix that discharges as carrier medicament with lactide polymer and multipolymer, and it can biological degradation, and is biocompatible.Wherein do not mention physicals by the polymer materials of ordinary hot forming method (extruding or moulding method) preparation as film.

Make us the interested US4719246 of being especially, wherein disclose blend L-lactide homopolymers, D-lactide homopolymers, their mixture or the method for the multipolymer of polymkeric substance and L-rac-Lactide or D-rac-Lactide and at least a non-lactide comonomer.This blend method is intended to preparation and contains synergistic poly-L-rac-Lactide segment and poly-D-rac-Lactide segmental composition.

Canadian Patent discloses a kind of L-rac-Lactide and D No. 808731, and the multipolymer of L-rac-Lactide contains II family divalent metal in its chain structure.It is said this 90/10 L-rac-Lactide/D, L-lactide copolymer (example 2) and L-lactide homopolymers are suitable for makes film and fiber.This 90/10 multipolymer is the multipolymer of snow-white color, and the L-lactide homopolymers can be made into transparent film (the polymer crystallization degree is high more opaque more, or is the homopolymer material of snowy white).Write " it is significant to contain this fact of metallic catalyst constituents that exists with the lactic acid salt form in the novel polylactide of the present invention " in this patent, " described polylactide can be made film and fiber with conventional thermoplastic resin working method ".But do not provide the data of physicalies such as film strength and snappiness.

Canadian Patent discloses L-rac-Lactide and D No. 863673, the composition of L-lactide copolymer, and wherein L-rac-Lactide and D, the ratio of L-rac-Lactide is respectively 97/3,95/5,92.5/7.5, and 90/10 and 85/15.The feature of these compositions is to can be used as the drafting that surgery is used.Tensile strength is very high, is about 100000psi, and elongation is about 20%.Wherein mention and use softening agent to increase flexibility.Should be mentioned that in the claim that percent by weight is less than 15 D, L-lactide composition.

Canadian Patent discloses L-rac-Lactide and D No. 923245, the multipolymer of L-rac-Lactide (example 15).It is said the polylactide that this 90/10 multipolymer is snow-white color.It is said that available conventional thermoplastic resin working method makes film and fiber with this polylactide.

US4719246 discloses the short-cut method of the multipolymer of the poly-L-rac-Lactide of a kind of blend, the polymkeric substance that gathers D-rac-Lactide, both mixtures and L-rac-Lactide or D-rac-Lactide and at least a non-rac-Lactide comonomer.The example that provides all is a mechanical mixture.Its special " interlocking " performance be because formed racemic compound (" carbon compound stereochemistry ", E.L.Eliel, McGraw-Hill, 1962, P.45).Racemic compound is made up of " interlocking " enantiomorph, and promptly D type and L type (or R type and S type) are attracted each other by polar forces each other.This can decide on power between D and the D (or L and L) and the power relative size between D and the L so that crystalline melt point rises or descends.Should adopt D and L homopolymer or long molecular chain for strengthening the required racemize polymer composition of this effect (referring to US4719246, the 4th hurdle, the 48th row).The high symmetry of this structure or regularity make them enough very strong polar forces to coincide each other or interlocking, also are identical or are mutually mirror image because of them.This has caused intensive crystallization tendency.The racemic compound technology has very long history, can trace back to classical chemistry.

US4661530 discloses a kind of poly (l-lactic acid) and/or poly-D, the mixture of L-lactic acid and block polyester carbamate or polyethers carbamate.The biodegradable material made of mixture can be used as the synthetic surrogate of biological tissue and organ in the outer material shaping technique thus.

The lactide polymer of making softening agent from unexposed mistake with the oligopolymer of lactide monomer, lactic acid and lactic acid or rac-Lactide in the prior art can be made into the submissive composition with highly-malleable.Above-mentioned prior composition all is not suitable for the thermoplastic polymer wrapping material.

Those skilled in the art understand, and the performance of a kind of performance of thermoplastics and another kind of thermoplastics is superimposed, and the result is unpredictable.For example, with regard to crystal polystyrene or OPS, be starved of this polyethylene and have satisfied performance, and polystyrene was developed many years, to satisfy processing and the final needs that use different grades OPS.

The universal of the present invention and first embodiment are, L-lactide homopolymers, D-lactide homopolymers, D, the multipolymer of L-lactide homopolymers and their monomer mixture, they can be used as well behaved thermoplastics with lactide monomer, lactic acid, rac-Lactide oligopolymer or lactic acid oligomer plasticising, and they can simulate the performance of the plastics that usually can not degrade (as polyethylene etc.) in environment.The polymkeric substance of this composition has following general formula And be with the elasticizer plasticizing that is selected from rac-Lactide, lactic acid, lactic acid oligomer and composition thereof.Lactic acid oligomer is preferably suc as formula shown in the II M is an integer in the formula, and 2≤m＜75, best 2≤m≤10.Softening agent preferably accounts for the 2-60% (weight) of polymkeric substance.Described polymkeric substance can be by being selected from L-rac-Lactide, D-rac-Lactide, meso D, the lactide monomer preparation of L-rac-Lactide and composition thereof.N is an integer, and best 150≤n≤20000.

Lactide monomer content is the 5-40% (weight) of polymkeric substance, and the content of rac-Lactide oligopolymer or lactic acid and oligopolymer thereof is 2-60% (weight).This composition possesses many required poly character, as kindliness, and the transparency and toughness.

A kind of method for preparing this Biodegradable composition also is provided in addition.This method comprises: mix heating and one or more lactide monomer of fusion and catalyzer; The above-mentioned monomer solution of polymerization forms polymkeric substance, and polymerization temperature is enough low, so that polymerization still imperfect tense can be stopped; The monitoring monomer content; Stopped reaction when residual monomer reaches a certain amount of before polymerization fully; Thereby unreacted monomer is trapped in the polymkeric substance.

A kind of method for preparing the polylactic acid plasticize polymkeric substance also is provided, has comprised: mixed heating and one or more lactide monomer of fusion and catalyzer; The above-mentioned monomer solution of polymerization forms polymkeric substance, midway stopped reaction not; Add softening agent in this polymkeric substance, described softening agent is selected from D-rac-Lactide, L-rac-Lactide, meso D, L-rac-Lactide, lactic acid, lactic acid oligomer and their mixture.

Second embodiment of the present invention comprise a kind of preparation can be in environment biodegradable method for compositions and be suitable for use as the polystyrene surrogate can be in environment biodegradable composition.Described composition contains the poly(lactic acid) unit of formula I, and (wherein n is an integer, 75≤n≤10000, alpha-carbon is the mixture of L configuration and D configuration, the D configuration is on the high side or the L configuration is on the high side), polymkeric substance wherein is by L-rac-Lactide or D-rac-Lactide (85-95 weight part) and D, L-rac-Lactide (15-5 weight part) preparation, the tensile strength of this polymkeric substance is at least 5000psi when non-oriented, tangent modulus is at least 200000psi, wherein is dispersed with the softening agent of 0.1-5% (weight).

The 3rd embodiment of the present invention provides the method for compositions that a kind of preparation can be degraded in environment, with contain poly(lactic acid) and one or more are selected from the ethylene glycol terephthalate polymkeric substance, degradation composition in the environment of the polymkeric substance of vinylbenzene, ethene, propylene, vinylchlorid, vinyl-acetic ester, alkyl methacrylate, alkyl acrylate or the blend of multipolymer and physical mixture thereof.

The 4th embodiment of the present invention provides method for compositions and a kind of composition that can degrade that a kind of preparation can be degraded in environment in environment.Said composition comprises poly(lactic acid) and can improve the blend of the compatible elastomeric physical mixture of blend of impact property.For example, this elastomerics can be Hytrel, i.e. the block polyester of polybutylene terephthalate crystallization hard segment and polyether glycol Great Wall Software segmental block polymer and so on.The block polyester that commodity are called Hytrel4056 (Du Pont) is a known embodiment.

Fig. 1 is as the rac-Lactide percentage composition of softening agent and the curve of tensile strength relation in the expression composition.

Fig. 2 is as the rac-Lactide percentage composition of softening agent and the curve of Young's modulus relation in the expression composition.

Fig. 3 be the expression composition in as the hundred parts of content of oligopolymer of softening agent and the curve of tensile strength relation, wherein curve A is represented 90/10 multipolymer, curve B is represented the 92.5/7.5 multipolymer.

Fig. 4 be the expression composition in as the oligopolymer percentage composition of softening agent and the curve of Young's modulus relation, wherein curve A is represented 90/10 multipolymer, curve B is represented the 92.5/7.5 multipolymer.

Fig. 5 is unannealed 90/10 L/D of example 5B, the differential scanning calorimetry of L-lactide copolymer (DSC) curve.

Fig. 6 is that the material of example 5B is in 70 ℃ of DSC curves after placing 100 minutes.

Fig. 7 is the DSC curve of material after 85 ℃ of annealing are spent the night of example 5B.

Fig. 8 is the DSC curve that is mixed with the example 5B material of 5% calcium lactate.

Fig. 9 provides the melt viscosity of lactide polymer of polystyrene and example 8B preparation and the correlation data of shearing rate.

Figure 10 is the DSC curve of example 8B multipolymer.

Figure 11 is the DSC curve that adds the L-lactide homopolymers in the example 8B multipolymer to.

Figure 12 is the DSC curve of blend composition that contains the example 23 of example 8B multipolymer and L-lactide homopolymers.

Figure 13 is 90/10 L-/D that is mixed with 5% (weight) polystyrene, the DSC curve of L-lactide copolymer.

The first general embodiment

Disclosed hereinly can in environment, can be degraded to environmentally acceptable compatible material fully by biodegradable composition.The intermediate product of degraded, promptly the short chain oligomer of lactic acid and lactic acid or rac-Lactide is the material that nature extensively exists, these materials are easy to the metabolism by various Institute of Micro-biology.Their natural final degradation production is carbonic acid gas and water.By suitable selection material, the expection equivalent of these compositions (as containing the composition of other material, filler or extender on a small quantity) also can degraded fully in environment.Above-mentioned composition provides acceptable material on the environment because with compare by the conventional nondegradation plastics of their alternate, it is faster and complete that their physical degradations and degradation process are wanted.In addition, because the whole or major portion of this composition is a poly(lactic acid) and/or by the rac-Lactide and the oligopolymer of lactic acid derivatives, so do not have or only residual the slower material of small amount of degradation speed arranged.This residue bulk product more higher than degradation rate has bigger surface-area.

General application the present invention has caused the of the present invention first general embodiment.D-rac-Lactide, L-rac-Lactide, D, the multipolymer of the homopolymer of L-rac-Lactide and D-rac-Lactide and L-rac-Lactide, L-rac-Lactide and D, the multipolymer of L-rac-Lactide, D-rac-Lactide and D, the multipolymer of L-rac-Lactide and D-rac-Lactide, L-rac-Lactide and D, the multipolymer of L-rac-Lactide, after with lactide monomer, lactic acid, rac-Lactide oligopolymer, lactic acid oligomer and their mixture plasticising, all can be made into and be applicable to material of the present invention.Softening agent can form by termination reaction when polymerization is incomplete as yet.The additional softening agent of adding in the polymkeric substance be can choose wantonly, lactide monomer (D-rac-Lactide, L-rac-Lactide, D, L-rac-Lactide or their mixture), lactic acid, lactic acid or rac-Lactide oligopolymer and their mixture comprised.Above-mentioned polymkeric substance is defined by formula I: N represents the polymerization degree (number of repeat unit) in the formula.Described polymkeric substance be by its incomplete polymerization residual monomeric plasticizer plastifying.Softening agent is more integrated with this polymkeric substance, and performance is good more.If desired, can monomer or oligopolymer in remaining in composition add additional monomer or oligopolymer.The lactic acid oligomer that can be used as softening agent is defined by formula II: M is an integer in the formula, and 2≤m≤75, best 2≤m≤10.

L-rac-Lactide, D-rac-Lactide and D, the ratio of L-rac-Lactide is unimportant to obtaining submissive thermoplastics.L-rac-Lactide, D-rac-Lactide and D, the component of L-rac-Lactide can change at very large-scale part by weight, to make homopolymer or multipolymer.The lactide monomer of Shi Yonging can be buied from market in the methods of the invention, so just needn't use monomer reactant itself, also need not preparation method of the present invention prepare.

The D-rac-Lactide is the dilactone or the cyclic dimer of D-lactic acid.Similarly, the L-rac-Lactide is the cyclic dimer of L-lactic acid.Meso D, L-rac-Lactide are the cyclic dimers of D-and L-lactic acid.Racemize D, the L-rac-Lactide comprises the mixture of D-and L-rac-Lactide.When this uses term " D, L-rac-Lactide " separately, it is meant and comprises meso D, L-rac-Lactide or racemize D, L-rac-Lactide.

One of Ji Lu method for preparing rac-Lactide is with acid by dehydrating lactic under high vacuum in the literature.Product distills under high temperature and low pressure.Rac-Lactide and preparation method thereof is discussed in following document: W.H.Carothers, G.L.Dorough and M.J.Johnson (J.Am.Chem.Soc.54,761-762[1932]); J.Gay-Lussac and J.Pelouse (Ann, 7,43[1833]); C.A.Bischoff and P.Walden (Chem.Ber.26,263[1903]; Ann.279.171[1984]); With Heinrich Byk (Ger.Pat.267,826[1912]); And Chem.Abstr.8,554,2034[1914]).

Optical activity acid can utilize various bacteriums to belong to Lactobacillus, as Lactobacilusdelbrueckii, and L.Salirarius, the almost any nontoxic hydrocarbons of L.casei or the like direct fermentation, by product or refuse prepare.Optical activity acid also can be taken racemic mixture apart with the salt of zinc ammonium salts or alkaloid such as morphine and be prepared.The L-rac-Lactide is that molecular weight is 144 white powder.Be used for the present invention if buy impure L-rac-Lactide, be preferably with anhydrous methyl iso-butyl ketone (MIBK) and come recrystallization purifying from market.Snowy white L-rac-Lactide crystalline fusing point is 96-98 ℃.

Be used to prepare D, the D of L-rac-Lactide, L-lactic acid can be buied.D, L-lactic acid can prepare with synthesis method, and with lactonitrile (acetaldehyde cyanhydrin) hydrolysis, or almost any kind of nontoxic hydrocarbons, by product or refuse prepare to belong to Lactobacillus direct fermentation with various bacteriums.D, L-rac-Lactide are that molecular weight is 144 white powder.If the not pure products that uses market to buy in the present invention, available anhydrous methyl iso-butyl ketone (MIBK) recrystallization purifying.With this commercially available product methyl iso-butyl ketone (MIBK) recrystallization that contains the semi-solid thing of fused mud coal under 90-130 ℃ of temperature, decolour with charcoal again.Like this behind the recrystallization three times, product under vacuum, nitrogen gas stream and room temperature tumble dried 8-24 hour.The snowy white crystal that makes like this comprises D, and L-rac-Lactide mixture, fusing point are 115-128 ℃.

When preparing composition, be preferably in airtight autoclave, having in the presence of the carboxylic acid tin ester of 18 carbon atoms at the most, liquid phase reaction and carrying out according to the inventive method.Composition also can be under the normal atmosphere, to prepare with the polyreaction under rare gas element such as the nitrogen protection.If polyreaction is carried out under oxygen or air, then decolouring to be arranged, so just make molecular weight and tensile strength descend.This method is to carry out under such temperature, makes polyreaction carry out slowly residual monomer being trapped in the viscid polymer melt in its later stage.The better temperature that can reach this purpose generally at the fusing point of pure L-rac-Lactide to pure D, between the fusing point of L-rac-Lactide, promptly at 95-127 ℃.Think at present that under about 129 ℃ of temperature this can not be limited in scope surely to of the present invention, and following situation can take place:

1.L-and D, the lactide monomer mixture fusion of L-lactide monomer forms eutectic mixture, this mixture is melt into a kind of flowable fluid, it is one, two or three kind of monomeric homogeneous solution.

2. mobile melt catalyzed polymerization becomes the solution of viscosity higher, and final unreacted monomer is trapped in the polymkeric substance, becomes solution rather than the phase that is uniformly dispersed.Because reaction is easy to decentralised control, and can not touch the polymer active end group of low levels, monomer no longer reacts.

3. polyreaction stops or slowing down greatly, and so at room temperature, the blend of monomer and polymkeric substance becomes solid solution, makes composition have plasticity, transparent and pliable and tough.

4. catalyst deactivation can not promote polyreaction in the fusion preparation so afterwards.

5. the plastifying composition is very stable, is following 142 ℃ of 1064Pa because remaining monomer has the boiling point of very high boiling point such as rac-Lactide, and closely related with its open chain changeization.

In addition, this method can be carried out under fusing point to the 200 ℃ temperature of L-rac-Lactide, and lactic acid or rac-Lactide fusion or solvent are blended into and are used for the polymkeric substance in step down then.Desired temperature is not higher than 200 ℃, because make multipolymer be easy to degraded.Elevated temperature can improve polymerization rate usually in 95-200 ℃ of temperature.Heating L-rac-Lactide and D under about 110 ℃ of-160 ℃ of temperature, the mixture of L-rac-Lactide can obtain a good result.

Catalyst system therefor of the present invention is to contain the carboxylic acid tin ester of 18 carbon atoms at the most.The example of this class acid is formic acid, acetate, propionic acid, butyric acid, valeric acid, caproic acid, sad, n-nonanoic acid, capric acid, lauric acid, tetradecanoic acid, hexadecanoic acid, stearic acid and phenylformic acid.Can good effect with stannous acetate and stannous octoate.

Catalyzer is to use by the custom catalysts amount.In general, catalyst levels is L-rac-Lactide and D, about 0.01-2% (weight) of L-rac-Lactide gross weight.Catalyst levels is about 0.01-1.0% (weight) preferably.Best catalyst levels is about 0.02-0.5% (weight).Under particular case, the accurate consumption of catalyzer depends on that to a great extent catalyst system therefor, processing conditions comprise time and temperature.The condition those skilled in the art is easy to determine accurately.

The reaction times of polymerization procedure itself is to be controlled by other reaction conditions, and reaction conditions comprises temperature of reaction, special catalyst, catalyst levels and whether uses liquid vehicle.According to the used reaction conditions of specific examples, the reaction times can change to several hours or several days from several minutes.The continuous heating of monomeric mixture is reached the degree that requires up to determining polyreaction.The degree of polyreaction can be determined by analyzing residual monomer.As previously discussed, can select temperature of reaction and improve monomeric incorporation, and by directly obtaining the plastifying composition in the polymerization reactor.When conversion of monomer is that the transformation efficiency of polymkeric substance reaches desired degree, when the composition of acquisition had required soffening, reaction stopped.Preferably in the embodiment, according to desired plasticizing rate, approximately the 2-30% rac-Lactide does not react in the present invention.

In general, when carrying out polyreaction, be preferably and do not have the impurity that contains reactive hydrogen, make catalyst deactivation and/or increased induction time because this impurity exists.Carrying out polyreaction is preferably under anhydrous basically condition and finishes.

Multipolymer of the present invention is preferably mass polymerization, suspension polymerization or solution polymerization and prepares.Polyreaction is to be to carry out in the presence of the liquid organic carrier having under inert, the normality, and this carrier for example has aromatic hydrocarbon such as benzene,toluene,xylene, ethylbenzene or the like; The dimethyl ester of the organic compound of oxidation such as methyl-phenoxide, 1,2 ethylene glycol and diethyl ester; Be generally cyclic saturated hydrocarbon that liquid stable hydrocarbon comprises that open chain, ring-type and alkyl replace such as hexane, heptane, hexanaphthene, alkyl cyclohexane, naphthane or the like.

Polymerization process can be in batches, semicontinuous or carry out continuously.When preparation is used for the lactide monomer reactant of later polyreaction and catalyzer, they can be admixed according to any method of known polymerization methods.Like this, catalyzer can be added in any monomer reactant.After this, the monomer that contains catalyzer can be admixed with other monomer.Another kind method is that monomer reactant is admixed each other, then catalyzer is joined in the reaction mixture.If desired, can or be suspended under inert, the normality catalyst dissolution in the liquid organic carrier.If desired, also monomer reactant can be joined in catalyzer, catalyst solution or the catalyst suspension with the solution of inertia organic carrier or the suspension of inertia organic carrier.Also have, catalyzer and monomer reactant can join in the reactor together.Reactor can be equipped with heat exchanger commonly used and/or mixing device.Reactor can be used any common equipment in the preparation catalyst technology.For example, the stainless steel still is the reactor that is suitable for.

Biodegradable composition in environment by the present invention's preparation, according to L-rac-Lactide, D-rac-Lactide, meso D, the different ratios of L-rac-Lactide can be used for making in the goods, for example film, fiber, moulded product and laminate, and these goods can be by manufacture method preparation commonly used.These goods can be non-medical, both external use, and they can replace non-ambient degradative plastics commonly used at this.

For example, silk can melt extrude multipolymer by spinneret and makes.Being prepared as follows of film with the solution-cast of biodegradation compound, removed then and desolvated, and also can suppress solid-state biodegradation compound with the hydropress that has heated platen, or extrude by die head.

Can make and in all sorts of ways as cooling and cooling cause copolymer moulded product of the present invention at a slow speed fast.

The expection equivalent of the present composition is the composition that contains a small amount of other material.If desired, the multipolymer of the present invention's preparation can come modification by adding linking agent, softening agent, tinting material, filler or the like.

Crosslinked action is with composition and free-radical initiator such as cumene hydroperoxide chemical combination, carries out in higher temperature lower mould then.Can improve thermotolerance and solvent resistance like this.Curing also can be carried out like this, and multipolymer and polyfunctional compound such as polyvalent alcohol chemical combination are also molded, or thermoforming under heating and vacuum.For grafting one extrusion reaction of carrying out curable polyester is the apparent method that makes crosslinking copolymers and chainpropagation.

When the preparation moulded product, can add filler to composition before solidifying.Filler can improve the performance of moulded product, comprises hardness, intensity, hot warm nature or the like.Known filler comprises aluminium powder, calcium carbonate powders, silica, kaolin (clay), Magnesium Silicate q-agent or the like.Best filler is a starch, it can with the abundant blend of composition to make the blend of the degraded of environmental organism fully.The improvement of other performance can obtain by other polymkeric substance and the multipolymer melt blending with composition and rac-Lactide, glycollide and caprolactone.

Composition of the present invention can be made the enhancement layer stampings according to currently known methods.Usually, the preparation of laminated product is, the matrix that fiber cluster or multi-layer sheet are molded into is consolidated into modular construction, and fixed is that fusion precursor or composition are flowed into filamentary material, and in mould or hydraulically-setting make polymkeric substance.Preparation during matrix used fiber comprise that natural and synthon are as the Mierocrystalline celluloses of wood, cotton, linen thread, hemp etc., glass, nylon, typel element or the like.

Composition of the present invention and preparation thereof further specify by following specific examples.

Example 1

80/20, L-rac-Lactide/racemize D, L-rac-Lactide

To be highly purified 160 gram L-rac-Lactides and 40 gram racemize D, L-rac-Lactide (Purac company produces, triple crystallizations) installs in 500 milliliters of round-bottomed flasks, is blown into drying nitrogen and spends the night.10 milliliters of stannous octoates are dissolved in 60 milliliters of dry toluenes, 10 milliliters of solvents are distilled in the dean stark trap, so that pass through the azeotropic point distillment this catalyst solution drying.From 50 milliliters of anhydrous toluene solutions of 10 milliliters of stannous octoates, take out 0.2 milliliter of part with syringe, be injected in the rac-Lactide in reaction flask.Continuation is blown into nitrogen with syringe needle, and this syringe needle links to each other by the outlet of the segment pipe that diaphragm of rubber links to each other with bubbler, and feeds reaction flask.Nitrogen flow remains on a per second 1-3 bubble.Flask is heated to 123-127 ℃ in oil bath.Add in the first step and to pine for, the rac-Lactide fusion and by shake with its thorough mixing.After this, the product very thickness that becomes.Heat after 20 hours, flask and colourless, transparent product are shifted out from heating bath, flask is smashed in cooling, washes to remove the glass in the product with liquid nitrogen.This multipolymer heating fluid press molding.88964.4N depress with 170 ℃ of temperature under in 2 minutes, can be compression molded into the 0.13-0.25mm thick film.Tensile property with Instron trier mensuration film the results are shown in table 1.Also want molding to be used for impact strength test into about 3.2 mm thick samples.Product is carried out thermogravimetic analysis (TGA) (TGA), record with sample in 4 minutes internal heating to 150 ℃ and 150 ℃ keep 60 minutes after the loss of weight.The weightlessness of sample is 19.5%, and no longer continues weightless after 60 minutes basically.Weightlessness is owing to the lactide monomer loss causes.The result of dsc (DSC) shows that composition begins heat absorption at about 110 ℃, and along with temperature rises to 200 ℃, it is crooked more that curve becomes.Do not observe fusing point.Sample is annealed under 85 ℃ of temperature and is spent the night, and test again.They are still transparent, colourless and flexible.The multipolymer sample can be repeated molding 6 times, and not have variable color or significantly loss of strength.Although molding repeatedly, it is transparent, colourless and very flexible that film is still.Table 1 is L-rac-Lactide and D when with rac-Lactide plasticising, the multipolymer of L-rac-Lactide ^(a)Examples of properties number 123 film thickness mm, 0.2 0.2 0.2 hot strength 1000psi, 3.9 1.7 7.9ASTM D638 percentage elongation %, 280 806 3.5100% modulus 1000psi 0.74--200% modulus 1000psi 1.20--tangent modulus 1000psi 36.6-289 notched Izod impact strength 0.63-0.40.3m-0.45kg/2.5cm^(b)-Mw, X1000 540 281 341Mn, X1000 270 118 97.5 residual lactide ^(c)% 19.5 27.8 2.7

(a) L-rac-Lactide/D, the weight ratio of L-rac-Lactide is 80/20

(b) about 3.2 millimeters, notched specimen

(c) 150 ℃ of temperature isothermal TGA weightlessness

Example 2

In 3 liters of round-bottomed flasks, pack into 1.84 kilograms of L-rac-Lactides, 0.46 kilogram of racemize D, L-rac-Lactide and 2.3 milliliters of stannous octoate solutions, similar to example 1.Fed argon gas 3 hours to this mixture, then isothermal heating in 125 ℃ of oil baths.This mixture fusion, thorough mixing under the shake has been made even, transparent, colourless fluids, and after several hours, this fluidic viscosity has improved in fact.After 64 hours, flask is taken out from heating bath, cooling, and from transparent solid product, remove glass fragment.The rubbery state composition is thinly sliced, and grinds to form 3.2mm or small grain size more with dry ice in shredder.Abrasive material in 38 ℃ air circulation oven dry several hours, at room temperature vacuum-drying is spent the night then.According to example 1 described preparation compression molded films, and the tensile property and the TGA weightlessness of mensuration film, list in table 1.

Example 3

The 79.98 gram L-rac-Lactides, 20.04 of packing in 250 milliliters of round-bottomed flasks restrain racemize D, and L-rac-Lactide and 0.20 milliliter of stannous octoate solution are similar to example 1.Nitrogen is blown in the flask, and in 125 ℃ of oil baths, heats.This mixture fusion is become colourless flowable liquid, and shaking flasks is come this liquid of thorough mixing.After 2 hours, oil bath temperature rises to 147 ℃, heats altogether 14 hours.Product is transparent, colourless vitreous state.Process mensuration and above-mentioned example class seemingly the results are shown in table 1.

Example 1 to 3 has illustrated the influence of temperature of reaction to performance of copolymer in the resulting composition.

Example 4

With the co-polymer membrane of example 1 and example 3 some months under water.After 3 week, the multipolymer of example 1 has fogged, and the multipolymer of example 3 is still transparent at about 2 months, and after 3 months, it is obviously fuzzy that the film of example 3 becomes, and the film of example 1 is a white and opaque.The water that contacts with example 1 is tasted for acid, and tasteless with the contacted water of the film of example 3.

The multipolymer that studies show that example 1 of table 1 data is biodegradable and can replace polyethylene in environment.Those skilled in the art of the present technique are not difficult to find out that in many kinds of packaging application, the comprehensive physicals of above-mentioned multipolymer is excellent.In the application of for example plastics rubbish suction box, universaling packing film, plastic shopping bag, multi-layer packaging paper, strap or the like, what their tensile strength and initial tangent modulus will be excellent compared with polyethylene composition.This multipolymer is roughly the same with the shape of the stress-strain curve of the LLDPE composition that is usually used in the rubbish container composition.Performance relatively list in table 2.

The comparison performance LDPE of table 2 polyethylene and polylactic acid polymer ^(a)NA272 LLDPE ^(b)Lactide copolymer ^(c)Tensile strength 1000psi 2.18 2.9 3.90ASTN standard C elongation % 216 500 280 tangent modulus 1000psi 54.9 51.0 36.6100% modulus 1000psi 1.77-0.74200% modulus 1.82-1.20HDT ^(d)264psi, ℃ 35 37 50

(a) LLDPE in this experiment, 5-10 mil, 2 inch per minute clocks.

(b) LLDPE obtains data by computer data.

(c) the L-rac-Lactide/D of example 1, the L-lactide copolymer.

(d) heat-drawn wire.

In controllable technology, above-mentioned rac-Lactide polyreaction can not stop when monomer is converted into polymkeric substance as yet fully.This has illustrated at example 1 and 2.Lactide monomer and lactide polymer agglutinating are very tight.In addition, said composition also can be prepared by rac-Lactide and prefabricated mixed with polymers.In this case, the three-dimensional chemical configuration of the rac-Lactide of adding can be identical or different, i.e. L-, and D-or D, the L-rac-Lactide is to be used for preparing polymkeric substance.

Mixing process is with the blend and carrying out in processing units commonly used such as mill roll or twin-screw mixer machine of molten polymer and lactide monomer.To use stiffening, vitreous state lactide polymer rac-Lactide plasticising always, and still keep transparent, colourless and tasteless basically.Rac-Lactide is not very unsettled, needs heating and nitrogen purging, is generally under 170 ℃ of-200 ℃ of temperature 20-60 minute, to remove the rac-Lactide in the gravimetric analysis.Under opticmicroscope, can not see that rac-Lactide is arranged in the film.The rac-Lactide domain structure belongs to submicroscopic level dimensionally.But the tough flexibility of this poly(lactic acid) can make it be used as the surrogate of environmental organism degraded, comes the polyolefine packing film of substituting disposable use.

Example 15-16:

A series of test is performed such, preparation L-and racemize D, and the L-lactide copolymer, with the rac-Lactide melt blending of various amounts, mensuration is as the physicals of the blend of the function of lactide composition content.Lactide monomer content is to be measured by known isothermal, thermogravimetric analysis (TGA) method.Lactide content mix and be molded as film before and measure afterwards.

According to observations, opening roller, two rollers grinds and makes rac-Lactide in the temperature required volatilization down of very high molecular weight lactide copolymer.This loss can be led to rolled-to-death rubber or be adopted lower molecular weight lactide copolymer (and corresponding than low mixing temperature with them) to reduce.Mixing and blend method are to use twin screw extruder with passing through preferably, can reduce the evaporable loss like this.Some the results are shown in table 3.The blend of polylactide and rac-Lactide softening agent is very flexible, and improves along with the increase of lactide content.They are colourless and transparent.Only can measure very weak rac-Lactide smell (preferably), and can not to pick out significantly be rac-Lactide flavor.But the plasticising film sample of table 3 is tear strength, easy folding and acanthopore and not broken or tear.When being placed in the refrigerator (5 ℃, 40), they are that some is hard, but still pliable and tough and collapsible and not broken.This film feel is very soft, and second-order transition temperature is lower than 37 ℃.When lactide content is lower than 20%, have during this film movement typical polyolefin film the sort of crackling.When lactide content was big, film had fold and " warming up " sense of polyvinyl chloride.

As shown in table 3, Young's modulus (initial tangent modulus) can be quite high, is similar to LLDPE (LLDPE).This shows the in stable condition of them.Low modulus is similar to new LDPE (film grade) (LDPE) with tensile strength.Physicals as the function of lactide content is depicted among Fig. 1 and 2.About table 3, when the lactide content of about 17-20%, tensile property is similar to the polyethylene that is used for rubbish container and shopping bag.

When hanging down lactide content, blend is similar to polypropylene.Some data is compared with table 3.Table 4 has illustrated and has been used for correlated common plastics.

Table 3: the tensile property of plasticising PLA (a) composition relatively

Mobile

Strain instance number composition % when rac-Lactide Young's modulus 1% secant modulus yield strength limit rupture strength is broken, TGA 1000psi 1000psi 1000psi % 1000psi %5 90/10, L-/D, L-1.3 289 291 00 7.5 3

Lactide copolymer 6 ＂ 17.3 119 119 2.23 4 2.29 2887 ＂ 19.2 95.5 90.3 1.97 5 4.24 5368 ＂ 19.6 88.7 88.7 1.72 4 2.12 2889 ＂ 20.5 50.3 50.3 1.21 5 2.16 33810 ＂ 25.5 33.7 22.9 0.32 4 2.44 546

(a) ASTM882; All samples are compression molded into the 0.13-0.25mm film, and except example 13 and 14, strain rate is 1cm/cm/min, D, and the L-rac-Lactide is racemic.

Continuous table 3: the tensile property of plasticising PLA (a) composition relatively

Mobile

Strain instance number composition % when rac-Lactide Young's modulus 1% secant modulus yield strength limit rupture strength is broken, TGA 1000psi 1000psi 1000psi % 1000psi %11 LDPE ^(b)--41.3 40.6 1.51 17 1.60 36512 LLDPE ^(c)--44.4 42.7 1.66 16 1.66 59913 diaxial orientation PE ^(d)--38.9 41.1 1.69 16 4.78 83814 ＂ ^(e)--35.6 38.5 1.68 16 5.20 94015 HDPE ^(f)--127.8 120.9 3.48 9 1.95 21616 pp ^(g)--174 174 5.08 5 7.34 6 (b) USI new LDPE (film grade) (polyethylene 213).(c) Exxon LLDPE (LLPE6202,57).(d) axial.(e) intersecting axle to.(f) Philips's high density polyethylene(HDPE) (HMN5060).(g) Clisso polypropylene (XF1932, melting index is 0.52).

Table 4: process data

Surrender the melt temperature Young's modulus melting index that crooked raw material trade mark and/or grade density are recommended

Gm/cu cm ℃ of tensile strength 35psi gm/10minLDPE (USI) polyethylene 0.924 182-288 1,820 0.37 8.0

No.213LLDPE, (Exxon) 6202.57 0.926 218 1,700 0.53 12.0HDPE, (Phillips) HMN 5,060 0.950 218-274 3,600 1.75 6.080%LLDPE, (Exxon) LPX 86 0.927 127----0.820%HDPE, (Octene, (process and use oily base) polypropylene XF1932 0.91 232-260 5,872 3.05 0.52, (PP-Chisso) polystyrene RI 1.05 204 7,900 4.50 1.8, (Amoco)

Table 3 has provided some data of rac-Lactide and polylactide mixture.The result is significantly different with the analogous composition of the example 1 for preparing with other method and 2.But those skilled in the art of the present technique will be appreciated that the variation that physicals is trickle a bit, the processing technology that this depends on compactness, the tension test condition of mixture and prepares this film.Show that from the contrast situation of table 3 component of rac-Lactide-polymeric blends can be controlled in the very wide scope, they are similar to many general non-degradable plastics.

Example 17:

Oligomeric poly(lactic acid) (OPLA) is to mix polylactide as follows and prepare.88% solution of L-lactic acid (956 gram) is joined in the three-necked flask (1 liter) that has thermometer in mechanical stirrer and the bottle.Reaction mixture is being led under the nitrogen in 150-190 ℃ of temperature and 2.66 * 10 ⁴Pa pressure concentrates 1 hour, removes up to the theoretical water of dilution.Except lactic acid and its oligopolymer, without catalyzer.Keep this temperature and vacuum, and continuous still battery 2 hours is up to 73% theoretical water of removing dehydration.

Required total time is 3 hours.At this moment reaction stops.With oligopolymer 0.5N NaOH titration in water sample and the bottle.26.2 gram lactic acid are arranged in distillating water liquid.Oligopolymer in the bottle (OPLA) is refluxed with excessive 0.5N NaOH, use the titration again of standard sulfuric acid then.Data are listed in table 5.When hot, the OPLA flowing property is good, and some cold flow.The polymerization degree is 3.4.After the polymer melt blend of example 19, be used for example 20.

The performance of table 5 example 17OPLA: the ester of the titrating acidometric titration of theoretical dehydrating amount is expressed as the total amount polymerization degree of lactic acid

％ ％ ％ ％

58 34.4 82.4 116.8 3.4

Example 18

Repeat the method for example 17, difference is to distill slowlyer.Heated 8 hours, during this period 2.66 * 10 ⁴Under the Pa pressure temperature is slowly risen to 175 ℃ by 63 ℃, sample has been removed 62.2% of theoretical water with proof in the titration bottle.The titration explanation polymerization degree is 4.3.By under 179 ℃ of temperature, heating and using the vacuum pump meter 2 hours, the molecular weight of OPLA is further improved.OPLA can not dissolve in 0.1N NaOH, and it is a white water liquid and can cold flow.This material is to have compared with example 1 second kind of example of the OPLA preparation method of high-polymerization degree more.In example 22 to 25, it mixes with polylactide.After measured, the polymerization degree is about 6-10.

Example 19

According to preparing the polymkeric substance of rac-Lactide with example 3 similar methods.L-/racemize the D of 90/10 weight ratio, the L-lactide copolymer carries out melt polymerization, is catalyzer with 0.02 part of (per hundred parts) anhydrous stannous octoate.Use similar methods, make 100%L-lactide homopolymers (L-PLA).With the multipolymer of 90/10 (weight)/homopolymer than in twin screw extruder under 177 ℃ of temperature with above-mentioned multipolymer and homopolymer melt blending.The weight-average molecular weight (Mw) that records blend with gel permeation chromatography is 182,000, and number-average molecular weight (Mn) is 83,000.With thermogravimetric analysis (TGA), residual lactide monomer is 1.7% (weight).This blend mixes the compound that can obtain example 20 with the oligomeric poly(lactic acid) (OPLA) of example 17.Tensile property is listed in table 6.

Example 20

The OPLA of the polymkeric substance of example 19 and example 17 on open type two roller mills under 163 ℃ of temperature melt blending 20 minutes.This mixture is compression molded into film and mensuration as shown in table 6.The gel permeation chromatography molecular weight is smooth, unimodal distribution, and Mw/Mn is 2.6, and Mw is 192,000, and Mn is 73,000.The performance of the melt blended material of table 6:90/10 polylactide and oligomeric poly(lactic acid)

Young's modulus breaking tenacity breaking strain Tg,

Composition % (weight) rac-Lactide 1000psi psi % C instance number polymer oligomer %, TGA (a) be (a) (b) 19 100 (a) ^(c)0 1.7 298 7,500 3 5,520 91 ^(c)9 ^(d)1.8 275 6,113 2--21 100 ^(e)0 1.6 308 7,478 3 5,822 70 ^(e)30 ^(f)0.4 254 5,052 3 4,223 60 ^(e)40 ^(f)0.0 202 3,311 2 3,824 50 ^(e)50 ^(f)0.0 106 2,334 25 3,525 40 ^(e)60 ^(f)0.0 36 1,180 129 35

(a) ASTM882; 0.13-0.25mm compression molded films, strain rate are 1cm/cm/min.

(b) by the determine with dsc method glass transition temp.

(c) 90% 90/10 L-/D, the blend of L-rac-Lactide * multipolymer and 10% poly-(L-rac-Lactide), example 19.

(d) the oligomeric PLA of example 17.

(e) 80% 90/10 L-/D, the blend of L-rac-Lactide * multipolymer and 20% poly-(L-rac-Lactide).(f) the oligomeric PLA * racemize of example 18

Example 21-25:

Multipolymer and 20% example, 9 described L-PLA melt blendings with example 19.This blend is the example 21 of listing in table 6, and its analytical data and tensile property also are listed in the table.With the polymkeric substance of example 21 successively with the OPLA melt blending of the example 18 of various consumptions, the listed mensuration example of table 6 22-25 as described above.Table 7 has been listed the GPC molecular weight of these compounds.Tensile strength and modulus are compared with OPLA% (weight) (lower curve) among Fig. 3 and Fig. 4.The molecular weight and the second-order transition temperature of table 7:90/10 polylactide and oligomeric poly(lactic acid)

(a)

Composition % (weight) residual monomer GPC * 10 ^{-3 (b)}Tg, ^(c)Instance number multipolymer oligopolymer % M _nM _wM _zM _w/ M _nC 21 100 ^(d)0 1.6 76 175 410 2.3 58 22 70 ^(e)30 ^(f)0.4 67 ^(g)136 299 2.0 42 23 60 ^(e)40 ^(f)0.0 61 ^(g)112 211 1.8 38 24 50 ^(e)50 ^(f)0.0 62 ^(g)114 223 1.8 35 25 40 ^(e)60 ^(f)0.0 69 ^(g)120 207 1.7 35 (a) measure residual monomer by TGA.(b) by the GPC determining molecular weight.(c) measure second-order transition temperature by DSC.(d) 90% 90/10 L-/D is after blend (e) example 21 (f) example 18 (g) blend of L-lactide copolymer and 10% L-Pla; Under 163 ℃ of temperature, use open type grinding roller melt blending.All D, the L-rac-Lactide is racemic modification.

Example 26-30

With second series multipolymer and OPLA blend.With preparing 92.5/7.5 L-/D, the L-lactide copolymer with example 19 and 21 similar methods.Here it is table 8 and 9 example 26.In an open type, two roller mill, blend is about 20 minutes under 163 ℃ of temperature with the OPLA of itself and example 18.Blend is compression molded into the 0.075-0.13mm thick film, and measures their tensile property and GPC molecular weight.Various performance inventories are plotted in Fig. 3 and 4 in table 8 and 9.Though can find out that the molecular weight of second series blend is lower, their tensile property value is high significantly.This is because of lactide monomer residual in the high polymers composition and/or changes less.All OPLA polylactide blends can easily be compression molded into tack-free transparent film.Table 9:92.5/7.5L-/racemize D, the molecular weight of L-lactide copolymer

% GPC * 10 ^-3(a) instance number OPLA M _nM _wM _zM _w/ M _nThe melt blended material performance of 26 0 63 124 228 1.9527 20 60 108 189 1.8128 30 48 80 125 1.6629 40 59 96 151 1.6530 50 56 92 141 1.64 (a) GPC table 8:92.5/7.5 polylactide and oligomeric poly(lactic acid)

Composition % (weight) breaking strain

Polymer oligomer rac-Lactide Young's modulus breaking tenacity %Tg ^(b)Instance number (c) is % (d), TGA (a) is (a) C 26 100 0 0.2 338 10 (a), 527 4 61 27 80 20 0.3 346 9,144 4 52 28 70 30 0.2 346 5,675 2 46 29 60 40 0.6 249 5,617 3 36 30 50 50 1.5 112 1,984 119 36 (a) ASTM882; 0.075-0.13mm compression molded films; Strain rate is 1cm/cm/min.(b) determine with dsc method glass transition temp.(c) 92.5/7.5 L-/D, the L-lactide copolymer.(d) example 18 all D, the L-rac-Lactide is a racemize

Example 31 and 32:

Contain or not the film sample of plasticizer-containing be exposed in the seawater of Daytona.Florida in March to the May.The pH value of water is 7.3-7.6, and saltiness is 33.2-38.4ppt.In test, water is warm gradually warm from 15 ℃-27 ℃.Sample is cut into galley proof, be placed in the seawater before, afterwards with certain hour measuring space tensile property.The results are shown in table 10.All samples have shown and have brightened and mechanical degradation, increase progressively in time.Do not have the sample of softening agent in seawater, to brighten after 6 weeks and degrade.The very fast degraded of OPLA rac-Lactide blend just has significant degraded after 3 weeks.The compound that is added with 20% rac-Lactide brighten immediately and expose 1 week the back with regard to obvious degradation.Table 10: the physicals after in seawater, exposing

Tensile property .1000psi ^(a)

The seawater strain, % instance number composition exposure duration Young's modulus 1% secant modulus yield strength breaking tenacity surrender fracture

All 31 90/10 multipolymers 0 305 292--7.6-4.7

5％L-PLA 3 ^(b) 315 301 -- 7.1 -- 3.1

6 ^(c) 317 317 -- 7.3 -- 3.0

9 ^(d) 228 230 -- 6.2 -- 3.0

12 ^(e)355 343--3.9--1.020 90/10 multipolymers 0 275 275--6.1--2.0

10% oligopolymer 3 ^(b)291 281--6.8--2.9

6 ^(c) 246 246 -- 3.9 -- 2.0

9 ^(d) 211 105 2.2 1.4 3 2.0

12 ^(e)103 103--1.7--1.032 90/10 multipolymers 0 300 298--7.0--3.0

1% fumaric acid 3 ^(b)292 291--6.5--2.5

6 ^(c) 318 318 -- 6.9 -- 2.0

9 ^(d) 226 223 -- 6.1 -- 3.0

12 ^(e)70 122--0.8--1.0 9 92.5/7.5 copolymer 1s ^(e)----------------Tai is crisp can't to measure----------------

20% rac-Lactide (a), 1.27 * 127mm film tape, 0.3-0.43mm; Strain rate: 1cm/cm/min.(b) 15-21 ℃ of Xian Haishui (d) 22-23 ℃ of Xian Haishui (c) 20-22 ℃ of Xian Haishui (e) 22-27 ℃ of Xian Haishui that refresh the water periodically that refresh the water periodically that refresh the water periodically refreshes the water periodically

Above-mentioned example confirms that all lactic acid compositions are flexible thermoplasticss, and is used for flexible plastic container.In order to compare, the homopolymerization of non-plasticizing (L-rac-Lactide) is a high-crystallinity copolymer, and their tensile strengths are about 7000psi, and unit elongation is 1%, and initial modulus is 500,000psi.It is highly brittle, and is opaque and be easy to split.It does not have thermoplasticity, and is opaque yet.Poly-(racemize D, L-rac-Lactide) is amorphous glassy polymers, and the second-order transition temperature of this polymkeric substance is about 50 ℃, and tensile strength is about 6300psi, and elongation is about 12%, and initial modulus is 160,000psi.Though it is transparent, also be highly brittle.Opposite fully, with lactide monomer plastifying L-rac-Lactide/racemize D, the polymkeric substance of L-lactide copolymer is different fully.For example, the tensile strength of plastifying polymkeric substance is about 3900psi, and elongation is 431%, and initial modulus is 56,000psi.The plastifying polymkeric substance is transparent and colourless, and blend must be heated to more than 100 ℃ just can remove softening agent.

Though, estimate that in theory the plastifying result has more non-crystalline structure, surprisingly generated rubbing property, transparent, stable composition, with and performance classes be similar to polyethylene, just be suitable for the needs of some packaging application.Owing to can in environment, can alleviate the plastic pollution problem by biodegradable material, can possess above-mentioned initial performance simultaneously so wish this material, the present invention has satisfied this needs just.

Present technique field professional as can be known superpolymer and softening agent very closely compatible blend be rare.Plastification makes initial physical performance and environmental organism separate the time of falling can in very large range to change.

The amount of softening agent depends on the characteristic of desired composition in the polymkeric substance.If rac-Lactide is used as softening agent, consumption is preferably 5-40% (weight), if only with rac-Lactide or lactic acid oligomer then consumption is 2-60% (weight).Find that surprisingly oligopolymer adds does not influence tensile strength or modulus basically when reaching 30% (weight).Referring to Fig. 3 and 4.Adding 30-60% (weight) oligopolymer can produce tangible plastification and weaken physicals.It is very economical adding lact-acid oligomer in composition, because it is more cheap than lactic acid superpolymer.Oligopolymer is by lactic acid or the preparation of any rac-Lactide.Notice it is important that lactic acid oligomer contains a large amount of lactic acid usually, unless be removed.This is an important consideration when preparing the composition with specified property.Those skilled in the art and the personnel that understand the technology of the present invention can select polymkeric substance, selective polymer and the softening agent ratio of reaction conditions to make suitable chain length, but so that obtain having and the common used packaging thermoplastics secondary processing composition of class physicals and the very fast degraded of phase intercommunication mutually.For example, the softening agent of higher dosage makes physicalies such as the flexibility of polymkeric substance and toughness improve, and still, its degradation speed has also improved.In addition, short chain polymer needs less softening agent, just can obtain the performance identical with long chain polymer.

First embodiment of the invention provided the method for preparing the environmental organism degradation composition, the plasticized polymer of the formula that said composition is (I) lactic acid on the other hand.This method comprises one or more lactide monomer of preparation and catalyzer; This monomer of polymerization, to form polymkeric substance, polymerization temperature is wanted enough low so that before the polymerization polyreaction is stopped fully; Measure monomeric amount to determine last monomeric amount; Before polyreaction is finished, stopped reaction when reaching the booking list body burden, thus this true quantitative unreacted monomer is trapped in the polymkeric substance.The lactide monomer of present method is to be selected from D-rac-Lactide, L-rac-Lactide, meso D, L-rac-Lactide, racemize D, L-rac-Lactide and composition thereof.Can at random join additional softening agent in the polymkeric substance, softening agent also is selected from L-rac-Lactide, D-rac-Lactide, racemize D, L-rac-Lactide, meso D, L-rac-Lactide, lactic acid, lactic acid oligomer, rac-Lactide oligopolymer and composition thereof.Monomer polymerization preferably carries out being lower than 129 ℃ of temperature.When in addition plasticized polymer being made final product, preferably under enough low temperatures, carry out, softening agent can be retained in the polymkeric substance.This temperature is approximately 129 ℃.If added additional monomer and/or oligopolymer, certain monomeric reservation is just so unimportant.

First embodiment of the invention also provides a kind of method of preparation I compound, and this method comprises one or more lactide monomer of preparation and catalyzer; Polymerization single polymerization monomer forms polymkeric substance; With another step softening agent is joined in the polymkeric substance, this softening agent is selected from D-rac-Lactide, L-rac-Lactide, D, oligopolymer of L-rac-Lactide, lactic acid and composition thereof.

It is 300-20 that composition of the present invention has tensile strength, and 000psi, elongation at break are 50-1000%, and tangent modulus is 20,000-250,000psi.As polyolefine surrogate preferably, the tensile strength of this composition is at least 3000psi, and elongation at break is at least 250%, and tangent modulus is at least 50,000psi.

Homopolymer of the present invention and multipolymer are water-fast, but continue to contact and will degrade at leisure with water.But compared with the displaced polyolefin compositions of polymkeric substance of the present invention, Degradation is faster.Thereby, after throwing away by the material of this polymer manufacture, in environment, be degraded into harmless material at leisure.If will be burned by the material of present composition preparation, they send purified blue flame.

Having provided on the other hand of first embodiment of the present invention uses biodegradation compound of the present invention to substitute the method for thermoplastic compounds, wherein thermoplastic compounds comprises first kind of orientable polymer unit, this method is to substitute first kind with second kind of orientable polymkeric substance can be orientated polymer unit, second kind of non-orientation of orientable polymkeric substance connects that to stretch intensity be 300-20, and 000psi, elongation at break are 50-10,000%, tangent modulus is 20,000-250,000.Wherein second kind of polymkeric substance comprises the poly(lactic acid) unit of formula (I) structure, and wherein n is a number of repeat unit, is integer, and 150≤n≤20,000, second kind of polymkeric substance elasticizer plasticizing, softening agent is selected from rac-Lactide, lactic acid oligomer, rac-Lactide oligopolymer and composition thereof.This method can be used for polyolefin compositions, particularly polyethylene and polypropylene, and polyvinyl chloride and polyethylene terephthalate.Except above-mentioned listed, this method also is applicable to the polymkeric substance of alternative vinylbenzene, vinyl-acetic ester, alkyl methacrylate, alkyl acrylate.Should be appreciated that the multipolymer that made by listed monomeric mixture and the mechanical mixture of above-mentioned multipolymer and polymkeric substance also are replaceable.

The second general embodiment:

As second embodiment biodegradation compound in environment is to be degraded into environmentally acceptable compatibiliser fully.The intermediate product of degraded is a lactic acid, and it can extensively be distributed in naturally and take place on the thing, and this thing can be by the very fast metabolism of multiple organism.Its Natural Degradation final product is carbonic acid gas and water.The expection equivalent of these compositions also can make its complete environment degradable by suitable selection material as the composition that contains a small amount of other material, filler or expansion agent.This composition is environmentally acceptable material, because their physical degradation and Degradation are faster and complete compared with the commonly used non-degradative plastics that is replaced by them.In addition, because the major portion of all compositions or composition is rac-Lactide or oligopolymer that poly(lactic acid) and/or poly(lactic acid) generate, the resistates that does not have residue or only have small part to degrade more slowly stays.The surface-area of this residue is greater than the surface-area of bulk product, and degradation rate is faster arranged.

Better composition of the present invention comprises the polygalacto acid unit of (I) repeating unit that has formula, and wherein n is 75-10, and 000 integer, alpha-carbon atom are D and L (or R and S) random mixture and have a kind of pure enantiomorph on the high side.When n hour, polylactic acid PLA is processing easily, but thinks it than n weakness when big, when n was very big, as 7000 or bigger, PLA was very tough, but was difficult to injection moulding.N is approximately 500-3000 preferably, can obtain the preferably comprehensive of melt processable and final use physicals.Monomer is selected from L-(or D)/D, the polymerization lactic acid of L-ratio or their cyclisation dipolymer, rac-Lactide, and this discusses afterwards.Lactic acid and rac-Lactide all can provide the PLA repeating unit, and as mentioned above, but rac-Lactide is better, because its easier required high molecular of better physicals that obtains.Because the structure of rac-Lactide is:

It has two symmetrical alpha-carbon atoms, so three types of rac-Lactides are arranged, i.e. D, D-(or D-); L, L-(or L-); With meso D, the L-rac-Lactide.

The D-rac-Lactide is the dilactide or the cyclic dimerization thing of D-lactic acid.Similarly, the L-rac-Lactide is the cyclic dimerization thing of L-lactic acid.Meso D, L-rac-Lactide are the cyclisation dipolymers of D-and L-lactic acid.Racemize D, L-rac-Lactide comprise 50/50 mixture of D-and L-rac-Lactide.When this uses separately, term " D, L-rac-Lactide " is meant and comprises meso D, L-rac-Lactide or racemize D, L-rac-Lactide.This used term " dispersive " be meant material be uniformly or fully with mixed with polymers.

The processing characteristics of pure L-PLA is very poor, splits easily and becomes opaque.Pure D, L-PLA processes easily, but does not have enough rigidity to satisfy the OPS compensation.The present invention's embodiment preferably is L-rac-Lactide/D in the multipolymer, and L-rac-Lactide ratio is 85/15-95/5, is preferably 90/10.When ratio greater than 95/5 the time, the multipolymer thermoforming is very easily broken, and it is opaque at room temperature to become easily.When ratio was lower than 85/15, lactide copolymer had and is lower than the required modulus of OPS compensation.Multipolymer between these two limit is in the preparation/processing units of general plastics technology, and fusion is quenched down, obtains transparent, colourless and special inflexible film and moulded product.By the above-mentioned product properties of making is very close with the performance of OPS.

Another advantage of the present invention is that all lactic acid copolymers can utilize cheap raw material.The maize treacle that is obtained by starch and corn can be fermented into L-or racemize D, L-lactic acid, and this depends on microorganism.Racemize D, L-lactic acid can be obtained economically by ethene,, makethes oxidation of ethylene to acetaldehyde that is, forms lactonitrile with the reaction of hydrogenation cyanogen again, and this lactonitrile is hydrolyzed into racemize D, L-lactic acid.The lactic acid distillation is easily obtained rac-Lactide.With common distillation/method of condensing lactic acid is converted into rac-Lactide, the stereochemical structure of unsymmetrical carbon is less than changing.

When L-rac-Lactide and D being discussed, during the reaction of L-rac-Lactide, be to be understood that specific reaction also can be used for the D-rac-Lactide to the L-rac-Lactide at this.Thereby, according to method in this narration, D-rac-Lactide and D, the product that L-rac-Lactide reaction obtains being equal to, the opticity that only different is at different directions.

Multipolymer of the present invention prepares preferably, heat monomeric mixture and form even molten mass, add catalyzer and make rac-Lactide carry out ring-opening polymerization, polyreaction is preferably in inertia, anhydrous atmosphere such as nitrogen or argon gas, carries out under normal atmosphere or the vacuum.Suitable catalyzer comprises bivalent metal oxide and organometallic compound such as stannous octoate, zinc acetate, cadmium acetate, aluminum acetate or butyric acid aluminium, titanium chloride, titanium benzoate and weisspiessglanz.Stannous octoate is a catalyzer preferably, because its higher solvability in monomer is made anhydrous form easily, and low toxicity.Required catalyst levels is based on monomeric about 0.02-2% (weight), even more preferably about 0.2%.The molecular weight of multipolymer and melt viscosity are to be controlled by the consumption of catalyzer and/or chain commentaries on classics section agent such as oxyacetic acid.The temperature of polyreaction is about 100-200 ℃.Minimum color forms will be below 140 ℃, and polymerization velocity is best more than the temperature at 135 ℃.Because racemize D under 127 ℃ of temperature, the fusion of L-rac-Lactide is preferably in 127 ℃ and carries out the polyreaction that conversion of monomer is a polymkeric substance more than the temperature.

As needing when pure and transparent with OPS compensation, multipolymer of the present invention is in inert atmosphere, on their fusing point, is generally 125-150 ℃ of following polymerization.The molten lactide multipolymer, is quenched, makes particle and be stored in the bag with knitted material shape and bar-shaped extruding by polymerizer, so that be used for molding and extrusion molding later on.

Similarly, transparent thermoforming packing film and moulding product are like this preparations, at the above temperature molding of multipolymer fusing point with extrude, and cool off this processed goods fast.Thereby multipolymer is still transparent, unless heating several hours more than the glass transition temperature Tg and below the fusing point Tm.The slowly cooling of thermoset sheet material, chunk, film and moulded work can produce spherulites in multipolymer, this has improved the thermostability of processed goods, but makes some decline of transparency.Use nucleator such as Sodium Benzoate, calcium lactate or the like also can quicken and strengthen crystallization.Between Tg and Tm, suitably stretched copolymer can cause the polymer molecule orientation, and can improve physicals basically and the transparency does not descend.

Dissimilar lactide polymer or copolymer blendedly can change its physicals substantially.For example, the crystallization that can obtain having q.s and type of the melt blending of high-melting-point L-lactide polymer and low melting point lactide copolymer keeps a kind of transparent material of transparency.Those skilled in the art of the present technique will be appreciated that the transparency of mold film, big rigidity, and higher heat-drawn wire, better hot workability and environmental organism degradation property, this is more rare good over-all properties.Thereby, but the polymkeric substance blend, and nucleation, orientation and control with molecular weight, with the processibility that obtains final bonded thermoplastics and final performance in wide variation very.

Lactic acid is got back in multipolymer of the present invention hydrolysis under moisture content.In air and under the humidity, obvious hydrolysis in 12 months-18 months, multipolymer become thickness, some is opaque and be highly brittle.In immersing water, multipolymer with 1-4 month with regard to hydrolysis, time length is determined in composition, molecular weight, room temperature, S/V, particularly the water content of multipolymer environment of living in.Microorganism can make lactic acid become carbonic acid gas and water.Roughly measure, be some months the storage period of multipolymer, just disappeared in 1 year under unusual humidity.

Following examples further specifies the present invention.Example 1B to 7B is preparation and evaluation composition class.Can find, opposite with prior art, L-rac-Lactide/D, the processing characteristics of L-lactide copolymer is different fully and prior art with physicals.

Example 1B:

The 160 gram L-rac-Lactides (Purac company makes, " Samsung " level) and 40 of packing in the dry flask of 500 milliliters of round bottoms restrain racemize D, L-rac-Lactide (Purac company makes, " Samsung " level).This mixture heated about 1 hour under 123-129 ℃ of temperature, and the entrance and exit by stopper is blown into nitrogen continuously simultaneously.Monomer becomes transparent molten mass, shakes this molten mass and comes thorough mixing.Preparation catalyst solution and azeotropic distillation drying just, are dissolved in 10 milliliters of stannous octoates (manufacturing of Polysciences company) in 60 milliliters of toluene; 10 milliliters of toluene distillations that will contain trace water are discharged by a drying tube in dean stark trap then.0.20 milliliter of stannous octoate solution suction is moved on in the melts, and thorough mixing.Be blown into nitrogen continuously, the viscosity of melts has increased in 3 hours afterwards.Under 123-127 ℃ of temperature, heated 20-24 hour continuously.The mixture placement is cooled to room temperature, under protective guard, puts into liquid nitrogen and further cool off flask.Vial is broken and remove glass cullet with liquid from polymkeric substance.Multipolymer is colourless and transparent, and has carried out a series of tests, lists in table 1B.Under 170 ℃ of temperature,, be used for tension test with hydrothermal solution platen press compression molded films.Be molded as the thick chunk of 3.2mm be used for shock test (notched izod test, ASTM, D256) and heat-drawn wire (ASTM, D648) mensuration.Measure glass transition temperature (Tg) and fusing point (Tm, the center of endotherm) with dsc (DSC).

Example 2B-7B

Repeat the method for example 1B, difference is L-and racemize D, and the ratio of L-rac-Lactide changes shown in table 1B, and test-results is listed in table 1B.It is good that the pure L-lactide polymer of example 7B always can not molding under 170-200 ℃ of temperature, because during the molding cooling, its is always serious broken.Usually, cooled off, it is just opaque.

Table 1B:L-rac-Lactide/racemize D, L-rac-Lactide/D in the performance composition of L-lactide copolymer, L-rac-Lactide (racemize)

Weight ratio 80,/20 85/15 87.5/12.5 90,/10 90,/10 9,5/5 100/0 instance number 1B 2B 3B 4B 5B 6B 7B color/transparency water white transparency----------------------------------→ White-opalescent thickness mil 10 5 15 11 5 10 5 hot strength 7.9 6.9 8.3 8.6 8.2 9.2 (a) 1000psi; ASTM D882 percentage elongation % 3.5 5.8 6.0 7.1 7.2 5.1 (a) tangent modulus 1000psi 289 221 694 210 268 748--notched Izod impact strength (b); Ft-lb/in.--0.44 0.34 0.31--0.41 (a) Mw, 1000 ' s--928---------M_n, 1000 ' s--218----------T _g, C (c) 53 53 48 44--46--T _m,--fragmentation of--125 133--152 190 (a) when cooling too crisply can not be tested (b) notched specimen to C (c), and the thick sample of-5/-8-inch impacts on the breach limit.(c) with carrying out dsc under 10 ℃/minute heating rate and the nitrogen.

Example 8B:

Similar to example 4B with 5B, preparation L-rac-Lactide/racemize D, the weight ratio of L-rac-Lactide is 90/10 multipolymer.With adding 1045.8 gram L-rac-Lactides and 116.4 gram racemize D, L-rac-Lactide in 2 liters of dry flasks of nitrogen purging.Add 1.0 milliliters of anhydrous stannous octoate solutions (every milliliter of toluene is 0.2 milliliter).This flask spends the night with nitrogen purging, is heated to molten monomer and thorough mixing then in 141 ℃ of oil baths, reduces Heating temperature to 125 ℃ and continuous 72 hours at leisure.Bleach at leisure during the polymkeric substance cooling.After removing glass, obtain muddy, colourless, vitreous state multipolymer.Gel permeation chromatography weight-average molecular weight (Mw) is 522,000, and number-average molecular weight (Mn) is 149,000.

The DSC of lactide polymer shows that Tm is 145 ℃ really, referring to Figure 10.Test with lactide polymer fusion, quenching with DSC, presentation of results does not have degree of crystallinity or fusing point again.But Tg is about 50-55 ℃.The result shows that this polymkeric substance is crystalline or amorphous, and this depends on its thermal process.

Example 9B-12B:

Method with example 1B prepares composition series, and difference is to use other L-and racemize D, the ratio of L-rac-Lactide, and heating is 2 hours under 125 ℃ of temperature, and heating is 14 hours under the 125-147 ℃ of temperature, and heating is 2 hours under the 147-131 ℃ of temperature.The results are shown in table 2B.

Table 2B:L-rac-Lactide and D, the stretching of L-lactide copolymer and modulus properties composition L-rac-Lactide and D, the weight ratio instance number 9B 10B 11B 12B color/transparency of L-rac-Lactide 70,/30 60,/40 20,/80 0/100 (racemize) is colourless/transparent--------------------------thickness, (mm) 0.15-0.23 0.1-0.15 0.1-0.13 0.13-0.18 tensile strength 1000psi ASTM D638 (a) 6.9 6.7 5.8 5.6 elongation % 3.2 3.0 2.7 2.8 tangent modulus 1000psi 287 293 275 278

(a) film separates the speed stretching with the folder mouth of 5.1mm/min, and chary speed is 127mm/min.

The presentation of results of above-mentioned example has only some composition to have the required performance of OPS compensation.To the required salient features of OPS class material be transparent and colourless, tensile strength greater than 7000psi, tangent modulus (measurement of rigidity) is greater than 400,000psi and thermoplasticity preferably.Table 3B has listed crystal polystyrene (OPS) and 87.5% (weight) L-rac-Lactide and 12.5% (weight) racemize D, and some of L-rac-Lactide random copolymers contrasts item by item. shows 3R:physical property is performance PLA example 3B crystal polystyrene notched Izod impact strength 0.3m-0.45Kg/2.5cm 0.4 0.4 ultimate tensile strength psi 8,300 7400 percentage elongation % 6.0 4.0 elastic modelling quantity psi 694 relatively; 000 450,000 deformation temperature ℃ (under 264psi load) (a)/10 fens (e) D1238 (G) of 84 proportions, 1.25 1.05 Rockwell hardness (b) M75 Vicat softening points, ℃ (c) 107 melt flow rate (MFR) 40-46 (d), 1.7 grams 1.6 grams/10 minutes (f) (a) depends on thermal process. (b) Tm=125 ℃ of of 10 ℃/minute of Shore D=97. (c) DSC is under (257 °F). (d) velocity of flow descends at a lower temperature. (e) listed by the preparation method. (f) this experiment.

Example 13B:

With the copolymer molding of example 2B, and molding and keeps high molecular weight several times determining whether occurring color on film repeatedly.This has determined whether processing capable of circulation of multipolymer, and this is an important parameter of implementing processing scheme.The result of table 4B shows, multipolymer although multipolymer is exposed in the air repeatedly, remains complete transparent and colourless under higher temperature behind heating and molding repeatedly.

Table 4B: lactide copolymer molding situation instance number process outward appearance Mwx1000 Mnx1000 Mw/Mn example 2B (a) do not have molding fully transparent 928 218-

Direct polymerization and colourless example 13B (a) example 2B multipolymer ＂ 301 13.5 2.22

(b) example 13B (a) example 2B multipolymer ＂ 137 56.7 2.42 behind the molding

Behind the molding 6 times (b)

(a) 85/15, L-rac-Lactide/racemize D, L-lactide copolymer.

(b) mould 167 ℃ of (333) temperatures and became the 5=mil films in 7 minutes.

Example 14B-18B:

The multipolymer compression moulding of example 2B, 3B and 6B becomes the thick film of about 0.54-0.75mm, and puts into the Instron trier of heating, with this film 5 times with the length that is stretched to it under 12.7 millimeters/minute speed and the 83 ℃ of temperature.After this film took out from the Instron trier, cooling obtained the thick film of about 0.13mm fast.These films are transparent and colourless.Measure tensile property and be listed in table 5B.In the time of the 8-10 that is stretched to their length times, it is opaque that optical haze and some appear in film, illustrates to have formed crystallization.

Gained presentation of results, the extremely thin film that makes have the suitable hardness and the transparency to the OPS compensation.Thereby, although the density of lactide copolymer is higher compared with polystyrene, there is not other material to compensate basically to OPS hardness.

Table 5B: orientation ^(a)Back L-rac-Lactide/racemize D, the performance composition L-rac-Lactide/D of L-lactide copolymer, weight ratio instance number 14B 15B 16B 17B 18B thickness (mm) 0.14 0.13 0.16 0.13 0.1 tensile strength 1000psi 14.0 14.7 15.0 13.0 16.0 elongations of L-rac-Lactide 85,/15 85,/15 85/15 87.5/12.5 95/5 (racemize), % 31.5 15.4 30.0 23.8 37.4 tangent modulus 1000psi-564 419 432 513 (a) are on the Instron machine, with the 12.7mm/min rate of extension, 5X orientation under 83 ℃ of temperature.

Example 19B:

The lactide copolymer film of table 1B is immersed the some months time in the water.About 2 months, multipolymer still was transparent, occurred some optical hazes after 3 months, and after being placed in the damp atmosphere on the shelf and repeatedly handling, in fact about 1 year of film does not still change.Though behind the some months, the Instron testing data of intensity and elongation has decline lentamente.In landfill, the film of putting into disappeared at 6 months-2 years, and time length depends on humidity, pH, temperature, composition, the surface-volume ratio of landfill, and biological activity.The burning of all films is purified blue look flame.

Example 20B:

The lactide copolymer of example 5B (quenching, compression molded films) is measured with DSC, learns that degree of crystallinity is less than 2%, referring to Fig. 5 under contiguous 130 ℃ of temperature.3.2 mm thick samples of example 5B multipolymer were annealed 16 hours in 85 ℃ of baking ovens.The sample optical haze that becomes, and the DSC of sample shows that (referring to Fig. 7) degree of crystallinity significantly improves.The heat-drawn wire (HDT) of this sample under 264psi is 90～95 ℃.The heat-drawn wire that does not have the similar sample of annealed to have is 50～55 ℃, and is identical with its Tg value.

Example 21B

5% (weight) calcium lactate and example 5B lactide copolymer in the hot-rolling grinding machine, under 170 ℃ of temperature, about 5 minutes of blend.Blend is pulled out from roller with sheet, and test.It is hard, and is tough and optical haze.Measure non-homogeneous zone under 82 times of opticmicroscopes, area size is several microns～30 microns.DSC shows that degree of crystallinity has increased (referring to Fig. 8) basically under about 145 ℃ of temperature, still hardenable and heating repeatedly.The above results and example 8B, 20B and 21B comparison shows that nucleator can better effectively produce crystallization in lactide copolymer.The salt of spendable nucleator such as carboxylic acid is preferably the salt of lactic acid.

Example 22B

At 500 milliliters that mechanical stirrer and nitrogen inlet and outlet are housed, in the three neck round-bottomed flasks, the 180.7 gram L-rac-Lactides and 40.2 of packing into restrain racemize D-, L-rac-Lactide (all being that Boehringer and Ingelheim make the S level).Under nitrogen purging, the inclusion of flask is heated to 110 ℃ with molten lactide, add 20.1 gram polystyrene (melting index is 3.5 grams/10 minutes for Amoco, R3).The swelling that polystyrene is bigger, and be heated in advance under 185 ℃ of temperature to stir and spend the night and be partly dissolved.Cool the temperature to 141 ℃, add 0.2 milliliter of first water stannous octoate solution (0.2 milliliter of/milliliter toluene).Stop to stir, under 3 day time, 141 ℃ of temperature, allow the rac-Lactide polymerization.After stopping to stir, big swollen polystyrene floats over top.The polylactide phase of cooling lower curtate is tested with DSC.Sample has lower Tg, and about 35 ℃, it lacks the apparent temperature conversion on the other hand.Compression molded films is transparent, colourless and very flexible.These results show that polystyrene is complete alternate formation crystallization.

Example 23B

The L-lactide homopolymers grinding roller blend of the lactide copolymer of example 8B and 20% (weight) example 7B preparation.The sample of homopolymer is analyzed with the DSC method, referring to Figure 11.The sample of blend is measured with the DSC method, learns that Tg is 59～63 ℃, and Tm is 150 and 166 ℃, referring to Figure 12.Film is transparent in a small amount of optical haze is arranged, and this depends on after the compression moulding their rate of cooling.The quenching sample when being heated to about 80～90 ℃, easily crystallization.As a result, the heat-drawn wire of blend is very high.Under 80～90 ℃ of temperature, the blend optical haze, but do not resemble thermal distortion 90/10 multipolymer of non-blend.The tensile property of non-orientation compression molded films is listed in table 6B, and compares with the similar gained data of polystyrene.

Table 6B: the comparison of example 23B polylactide and crystal polystyrene blend

Example 23B ^(a)Crystal polystyrene ^(a.b)Thickness: (mm) 0.2 0.3 tensile strength ASTMB882 * 1000psi, 7.7 6.0 elongation % are to 6.5 3.2 tangent modulus that rupture * 1000psi 323 267 (a) film, non-orientation, compression molding sample (b) melting index: 1.7

The explanation of this example, melt blending is an excellent process of improving performance of copolymer, can obtain the excellent properties similar to polystyrene like this.Have the homopolymer consumption of L-rac-Lactide (or D-rac-Lactide) of polymkeric substance big more based on blend, heat-drawn wire is high more, but turbidity has also improved.This adding homopolymer can be used with other method that improves the polystyrene type performance, and still keeps transparency.

Another example is, can improve tensile property by the oriented film of polymer manufacture.Doubly stretch with 8-10, physicals still improves, but material has become optical haze.Thereby orientation degree also needs control, and merges consideration with other performance of improving one's methods, to obtain excellent polystyrene type performance.

Example 24B～27B

Example 24B～27B is that rac-Lactide is having polymerization under the controllable amounts chain-transfer agent, illustrates with chain-transfer agent such as oxyacetic acid may command molecule amount, the results are shown in table 7B.Between the inverse of chain-transfer agent consumption and weight-average molecular weight approximate linear is arranged.Chain-transfer agent is a lactic acid preferably.Table 7B: control molecular weight with chain-transfer agent

PPH of ^(a)Instance number CTA M _n ^(b)M _w ^(b)M _w/ M _n24B 0.22 13,500 107,300 8.025B 0.45 12,800 66,700 5.226B 0.90 7,300 29,900 4.127B 1.80 4,700 13,900 2.9 (a) in polymerization formula, oxyacetic acid chain-transfer agent (CTA) umber of per 100 parts of rac-Lactides.(b) gel permeation chromatography, in tetrahydrofuran solvent, under 23 ℃ of temperature, with 106,

10 ⁵, 10 ⁴With 10 ³Anhstrom post, number-average molecular weight Mn and weight-average molecular weight Mw are relatively

The monodisperse polystyrene criterion calculation.

Example 28B

The thick compression moulding film of 0.1mm of example 2B lactide copolymer is measured as protective film with the ASTM method.The results are shown in table 8B.Lactide copolymer is more much better than polystyrene to the protection of carbonic acid gas and nitrogen.Other protective polymer films compared with some, lactide copolymer is the protective film that is applicable to many packaging application.

Table 8B: example 8B is to the perviousness of gas ^(a)The crystallization of gas lactide copolymer is poly-to benzene two vinylidene chlorides

Example 2B vinylbenzene ^(b)Acid esters one vinylchlorid

Multipolymer ^(b)Cm ³/ 645cm ²Under/24 hours/normal atmosphere

CO ₂ 32.1 900 15～25 3.8～44

O ₂350 6～8 0.8～6.9 19.9 (a) ASTM D1434～75, example 2B is the thick compression mould of 0.1mm.(b) get data by modern plastics encyclopedia.

Example 29B

Sheet example 1B～6B lactide copolymer that 3.2mm is thick is immersed in the mixture of sherwood oil and methylene dichloride and spends the night, and the ratio of sherwood oil/methylene dichloride is 70/30～60/40, and in being placed on boiling water, multipolymer becomes foams.Formed the irregular foam of abundant foaming.

Example 30B

The crystal polystyrene (201 types, Huntsman Chemical company produces) and the melt viscosity of example 8B lactide polymer of industry are compared.With 5 kilogram load of standard with under 200 ℃ of temperature, the melting index of polystyrene (ASTM D1238 (G)) is 1.6 grams/10 minutes.Under the same conditions, the melting index of lactide polymer is 40-46 gram/10 minutes, still, is 8.0 grams/10 minutes under 160 ℃ of temperature.The molten viscosity of touching of two kinds of polymkeric substance by observing the Instron capillary viscosimeter is come in more detail relatively melt viscosity.Relatively the results are shown in Fig. 9.Extrude with injection molding in the shearing rate that is subjected to usually be about 100-1000 second ^-1The data of analysis chart 9 show, under 160 ℃ of temperature under the melt viscosity of lactide polymer and the 200 ℃ of temperature melt viscosity of polystyrene very close.

The The above results explanation, lactide polymer can be lower than under the temperature of polystyrene processing temperature in temperature, with very close method melt-processed.

Example 31B-34B:

(recrystallization is also dry) Study of Meso-Lactide (meso D, L-rac-Lactide) of purifying is carried out a spot of tentative polymerization, becomes homopolymer and multipolymer.With GPC method determining molecular weight and and D, the analogue of L-rac-Lactide is relatively.The results are shown in table 9B.Polymer melt is pressed into film, measures their physicals and also compares, and is shown in table 10B.Test with molecular weight with different sheets are thick, the tentative shortcoming of multipolymer is similar.The homopolymer of Study of Meso-Lactide is more weak.Table 10B:D, the physicals of L-and Study of Meso-Lactide polymkeric substance and multipolymer relatively

Polymer composition elastic modelling quantity fracture tensile strength elongation at break thickness strain rate instance number 100psi 100psi % mm 2.54cm/min31B D, L-lactide homopolymers 278 5.6 2.8 0.13-0.18 0.2532B Study of Meso-Lactide homopolymers 345 3.8 3.5 0.23 0.2533B 90/10L-/mesos 190 7.9 3.8 0.3-0.38 0.25

Lactide copolymer 34B 90/10L-/D.L-323 8.6 4.6 0.1-0.15 0.25

1 lactide copolymer (a) compression molded films table 9B: the GPC molecular weight ratio of meso and rac-lactide polymkeric substance and multipolymer

GPC×10 ^-3

Res. instance number composition Mon., % M _nM _wM _zM _w/ M _n31B D, L-PLA--97.5 341 757 3.4932B meso PLA, 2.76 62.5 152 264 2.4233B 90/10, L-/meso 1.67 29 142 301 1.6734B 90/10, L-/D, L--91.3 201 350 2.20

The general introduction of second embodiment of the invention composition comprises a kind of polymkeric substance of environmental organism degraded, this polymkeric substance comprises formula (I) topology convergence lactic acid units, wherein n is 75-10,000 integer, alpha-carbon atom is the mixture of L-and D-form, and or the D-unit is on the high side or the L-unit is on the high side, and wherein polymkeric substance is the suitable alternative of polystyrene.The D-of polymkeric substance and L-unit are preferably by 85-95 weight part L-rac-Lactide or D-rac-Lactide and 15-5 weight part D, the preparation of L-rac-Lactide.

More the biodegradation compound in environment that improves performance similar in appearance to having of polystyrene comprises that (wherein n is 75-10 for the polygalacto acid unit of formula (I) structure, 000 integer, alpha-carbon atom be L-and D-form random mixture and or the D-unit is on the high side or the L-unit is on the high side, with the blend of the lactide homopolymers of D-rac-Lactide or L-rac-Lactide.N is 150-10, and the composition of 000 integer has the over-all properties of intensity and melt processable preferably.

The method for compositions summary for preparing second embodiment comprises L-rac-Lactide or D-lactide monomer and D, L-lactide monomer and catalyst mix, heating and fusion, thereby the content of L-lactide monomer or D-lactide monomer is the 85-95 weight part, D, the content of L-lactide monomer is the 15-5 weight part, and makes homogeneous solution; This solution of polymerization; Handle this polymkeric substance improving its performance, thereby make the polymkeric substance that is suitable for replace polystyrene.The performance of composition can be regulated with the following method, adds nucleator; Blend adding D-rac-Lactide or L-lactide homopolymers are to make a kind of mechanical mixture; Polymer orientation; Blend adds nucleator and D-rac-Lactide or L-lactide polymer; Blend adds nucleator and D-rac-Lactide or L-lactide polymer and makes polymer orientation; In polymerization procedure, add chain-transfer agent and become the polystyrene surrogate to regulate their performances, under comparatively high temps, anneal, and add additional softening agent, this softening agent is selected from D-rac-Lactide, L-rac-Lactide, meso D, L-rac-Lactide, lactic acid, rac-Lactide oligopolymer, lactic acid oligomer and composition thereof.Be softening agent if a kind of monomer is elected to be, add with composition in the oligopolymer of the used different stereochemical structure of gained polylactide, can make the product of uniqueness.Under inert atmosphere neutralization reaction temperature is preferably 140 ℃ or low temperature, carry out polymerization, can not make coloring matter.In case understand technology of the present invention, can use the various comprehensive of above-mentioned processing, make the excellent properties that those skilled in the art see fit.

Mention as above-mentioned first embodiment, the higher dosage of monomer or oligopolymer can have positive effect.Second embodiment herein, the less consumption of monomer and oligopolymer can obtain hardness preferably.Plasticizer dosage is that 0.1-5% is better.Usually contain the add-on after plasticizer dosage depends on polymerizing condition or polymerization in the composition.Additional monomer as softening agent is selected from D-rac-Lactide, L-rac-Lactide, meso D, L-rac-Lactide, racemize D, L-rac-Lactide and composition thereof.The oligopolymer that also can add rac-Lactide or lactic acid.Monomer or oligopolymer that the adding stereochemical structure is different from polymkeric substance in the composition can make the unique combination thing.

Second embodiment of the invention also provides the method that substitutes thermoplastic compounds with biodegradation compound of the present invention, and thermoplastic compounds comprises first kind of oriented polystyrene unit, the polymkeric substance of available second kind of orientation substitutes first kind of orientated polymer, have tensile strength during the non-orientation of second kind of orientated polymer and be at least 5,000 and tangent modulus be at least 200,000; Wherein second kind of orientated polymer comprises the poly(lactic acid) unit of formula I structure, wherein n is a number of repeat unit, n is 75≤n≤10,000 integer, alpha-carbon atom is the mixture of L-and D-form, and or the D-unit is on the high side or the L-unit is on the high side, wherein polymkeric substance is 85-95 weight part L-or D-rac-Lactide and 15-5 weight part D, the preparation of L-rac-Lactide, this polymkeric substance can be used 0.1-5.0% (weight) elasticizer plasticizing, and softening agent is selected from the oligopolymer of rac-Lactide, lactic acid, oligopolymer of rac-Lactide and composition thereof.

The expection equivalent of the present composition is the composition that contains a small amount of other material.If desired, can add the composition that linking agent, other softening agent, tinting material, filler or the like come modification the present invention preparation.

Composition melt-processable at this becomes the useful article have from support structure, as application container, tableware, plate, plate, beverage cup, part meal dish, syringe, medical basin, packing film or the like.Said composition has the characteristic and the alternative polystyrene of common polystyrene, goes back degraded by environment.Said composition is specially adapted to disposable goods, or the goods that the short period of time uses before losing.

The 3rd general embodiment:

The 3rd embodiment discloses the blend of poly(lactic acid) (PLA) with polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET) and polypropylene (PP).It is compatible with thermoplastic molten commonly used that the present embodiment discloses poly(lactic acid), and to the effectiveness of their physicalies.

Disclosed herein in environment degradation composition be to degrade to small part.The poly(lactic acid) part of composition can be decomposed quite apace compared with the steady component of blend, and causes the physicals deterioration of blend.For example, when composition is closely, and with the even blend of small grain size, the deterioration of its physicals has been destroyed original product.Provide environmentally acceptable material at this composition, because their physical degradation and degraded are faster compared with non-degradative plastics commonly used.In addition, because the overwhelming majority of this composition is rac-Lactide or oligopolymer that poly(lactic acid) and/or lactic acid generate, only leave a small amount of thermoplastics (as polystyrene) of degraded very slowly.This residue has bigger surface-area and wishes more faster than the decomposition of body shape product.

The D-rac-Lactide is D-lactic acid binary lactone or cyclic dimer.Similarly, the L-rac-Lactide is the cyclic dimer of L-lactic acid.Meso D-, L-rac-Lactide are the cyclic dimers of D-and L-lactic acid.Racemize D, L-rac-Lactide comprise 50/50 mixture of D-and L-rac-Lactide.When this uses separately, term " D, L-rac-Lactide " is meant and comprises meso D, L-rac-Lactide or racemize D, L-rac-Lactide.Poly(lactic acid) can be by above-mentioned one or more rac-Lactide preparations.

Example 1C:

Polystyrene and the blend of poly(lactic acid) solvent and use the ethylene dichloride solvent casting are to determine best consistency.The solvent casting film is translucent, and appearance does not resemble dried cheese.The sample appearance looks like uniformly, and folding and anti-moving back and forth and can be broken.Under 310 times opticmicroscope, observe, demonstrate 3 microns or littler non-uniform area.This blend has extraordinary consistency.More than 2 years, sample does not have " albefaction " phenomenon of fugitive material, does not prove that the physicals of its degraded changes yet.

Example 2C:

Polypropylene 8525 (Hercules) and poly(lactic acid) about 204 ℃ of following melt blendings in the Brabender machine.The ratio of made PP/PLA is 100/0 (control group), 90/10 and 75/25.

Example 3C-5C:

Poly(lactic acid) and polystyrene melt blending.Promptly can use high molecular weight polystyrene (Piccolastic, E-125, Hercules), also can use low-molecular-weight polystyrene (Piccolastic, D-100).Can also use general purpose polystyrene (Huntsman polystyrene 208), crystal polystyrene.They are mixed under about 163 ℃ in the Brabender machine with poly(lactic acid) with different ratios.

The ratio of used polystyrene/poly(lactic acid) is 100/0 (control group), 90/10 and 72/25 (Huntsman 208, general purpose polystyrene).

Example 6C-7C

Use two types polyethylene terephthalate (the Kodapak TN-0148 that " Clearstuff " that Goodyear is produced and Eastman are produced).With them 90 ℃ of following dried overnight, with poly(lactic acid) about 274 ℃ of following melt blending several minutes in the Brabender machine.The melt viscosity of poly(lactic acid) descends.

Example 8C-16C:

The contrast and the blend of polypropylene, general purpose polystyrene and the polyethylene terephthalate (Eastman is produced) of example 2C-7C are ground with the Abbey shredder, and compression moulding is into about the thick film of 0.13mm.At about 204 ℃ of temperature lower mould polypropylene-polylactic acid films, preparation polystyrene-poly lactic acid film under 121-149 ℃ of temperature; At about 274 ℃ of temperature lower mould polyethylene terephthalate one polylactic acid films.After placing 24 hours under 50% relative humidity and the 23 ℃ of temperature condition, test with Instron.Control group is also handled with similar methods.The sample of compression molded films is placed in the Atlas weatherometer measures weathering resistance, trier is 102 minutes solar light irradiations and rainwater circulation in 18 minutes.1C is shown in the results are shown in of these examples.

Example 17C-19C

100% poly(lactic acid) with poly-(D, L-lactic acid) preparation is made three samples as stated above, and different is that film thickness is 0.25-0.38mm.Test is carried out according to the method for following example 20C-27C, and different is that second sample is to test after exposing 82 hours under 50% relative humidity and the about 22 ℃ of temperature.

Example 20C-27C:

(HDPE is 0.960g/cc) with poly(lactic acid) melt blending 10 minutes under 151 ℃ of temperature in BrabenderPlasticorder with high density polyethylene(HDPE).The blend ratio of high density polyethylene(HDPE)/poly(lactic acid) is 100/0 (control group), 90/10,80/20 and 50/50.Two samples of every kind of blend preparation.This blend grinds with the Abbey shredder, and is compression molded into the 0.25-0.38mm film.This film sprays with the carbon arc irradiation in 51 minutes of Atlas aging sample machine and 9 minutes water and tests.Temperature is from room temperature to 60 ℃.The type of the tensile strength of this sample, elongation at break and tension fracture all is listed among the table 2C.

Example 28C-33C:

(LDPE is 0.917g/cc) with poly(lactic acid) melt blending 10 minutes under 151 ℃ of temperature in BrabenderPlasticorder with new LDPE (film grade).The blend ratio of new LDPE (film grade)/poly(lactic acid) is 100/0 (control group), 90/10 and 50/50.Two samples of every kind of blend preparation.This sample is handled and is measured according to the method for example 20C-27C.The results are shown in table 2C.

Example 34C:

In having mechanical stirrer and nitrogen gangway 500 milliliters, three neck round-bottomed flasks, put into 180.7 gram L-rac-Lactides and 40.2 gram racemize D, L-rac-Lactide (Boehringer and Ingelheim, S level).The inclusion of flask is heated to 110 ℃ under nitrogen purging, makes the rac-Lactide fusion, add 20.1 gram polystyrene (Amoco R3, melting index is 3.5g/10min).Spend the night and be heated in advance under 185 ℃ of temperature when stirring, the abundant swelling of polystyrene also is partly dissolved.Cool the temperature to 141 ℃ of temperature, add 0.2 milliliter of anhydrous stannous octoate solution (0.2 milliliter of/milliliter toluene).Stop to stir, allow rac-Lactide polymerization three days under 141 ℃ of temperature.After stopping stirring, high swollen polystyrene floats over the top.The polylactide phase of cooling lower is measured with dsc (DSC).The Tg of sample is lower, and about 35 ℃, its apparent temperature transforms less in addition.Compression molded films is transparent, colourless and very pliable and tough.This result shows that under such condition polystyrene is complete discontinuous formation crystalline.

Example 35C:

Poly(lactic acid) and crystal polystyrene roll-in blend.Blend demonstrates polystyrene and is dispersed in superior compatibility in the poly(lactic acid).In end runner mill, 5% (weight) polystyrene is dispersed in L-/racemize D of 90/10 under 170 ℃ of temperature, in the L-lactide copolymer.The material preformed casse that becomes, and learn to have very large degree of crystallinity with heat analysis.This example explanation, under such condition, polystyrene is easy to produce crystallization in poly(lactic acid).The heat analysis (referring to Figure 13) of this material shows that after heating and cooling this material is still crystalline.

Example 34C and 35C explanation, the non-degradative plastics blend of poly(lactic acid) and environment can obtain the final performance of mixture according to mixing or the used method of blend.

All types of Brabender melt blended materials all have 10 microns or littler inhomogeneous small-particle.Before the simulation weathering test, measure tensile strength afterwards.After the Atlas weatherometer carried out 1248 hours (52 days) test, all polypropylene samples all bleached, crisp especially and can not test.The polypropylene sample is tested behind the short period interval again, the results are shown in table 1C.In the Atlas weatherometer, after the about 300 hours weathering tests, sample has tangible environment degradable.

The blend of polystyrene and poly(lactic acid) has environment degradable after simulating weathering test in 300 hours.The polyethylene terephthalate blend also has the visible environment degradable after test in about 300 hours.Table 1C: the tensile strength of film before accelerated weathering test and afterwards ^(a)Blend ratio and tensile strength of material ^(b)/ % elongation

Before (hour)

310 340100/0?PP/PLA ^(c) 1665/61 585/1.6 494/1.790/10，PP/PLA 1568/51 954/3.2 346/--75/25，PP/PLA 1124/14 370/1.1 254/1.0100/0?PP/PLA ^(d) 3200/2.0 1066/1.0 --90/10，PS/PLA 2350/2.0 582/1.0 --75/25，PS/PLA 1493/1.6 484/1.0 --100/0?PET/PLA ^(e) 3036/-- 3509/3.0 --90/10，PET/PLA 2147/-- 1378/3.0 --?75/25，PET/PLA 2743/-- 2041/3.0 --

(a) weatherometer, 102 minutes solar radiation and rainwater circulation in 18 minutes.

(b) 0.05in/min uses the Instron trier.

(c) the Hercules polypropylene 825.

(d)Huntsman?208。

(e)Tennessee?Eastman，Kodapak?TN?0148。

Before simulating weathering test and afterwards, measure the physical strength of poly(lactic acid), high density polyethylene(HDPE), new LDPE (film grade) and their blend, the results are shown in table 2C.

Table 2C: before in weatherometer, exposing and afterwards, the physicals of polyethylene (PE), poly(lactic acid) (PLA) and their blend

Polymkeric substance/weathering test in the material (c) is the fail in tension material (d) ^(a)The Class1 00%PLA of the blend ratio exposure duration hour tensile strength psi elongation at break % of PLA ^(e)0/,100 06,030 2.2 fragility 100%PLA 0/,100 0 ^(f)5,670 2.1 fragility 100%PLA, 0/,100 92 too crisp can not the test--fragility 100 %HDPE ^(g)10,0/0 03,540 8 ductility 100 %HDPE 10,0/0 233 1,400 1 fragility HDPE/PLA 90,/10 03,480 7 ductility HDPE/PLA 90,/10 233 1,720 1 fragility HDPE/PLA 80,/20 03,180 4 fragility HDPE/PLA 80,/20 125 2,150 2 fragility HDPE/PLA, 50,/50 02,720 2 fragility HDPE/PLA, 50,/50 233 too crisp can not the test--fragility 100 %LDPE ^(h)10,0/0 01,320 80 ductility 100 %LDPE 10,0/0 125 1,250 67 ductility LDPE/PLA 90,/10 01,190 31 ductility LDPE/PLA, 90,/10 125 855 14 ductility LDPE/PLA, 50,/50 01,160 4 ductility LDPE/PLA, 50,/50 125 too crisp can not the test--fragility

(a) compression molded films, 0.25-0.38mm is thick.

(b) melt blending 15 minutes under 151 ℃ of temperature in Brabender Plasticorder.

(c) per hour in the irradiation of 51 minutes carbon arcs and 9 minutes water spray and circulate.Temperature is a room temperature

To 60 ℃.

(d) maximum elongation rate in strain curve.

(e) poly-(D, L-lactic acid) (η) is 1.16dl/g, under 25 ℃, among the THF.

(f) in 50% relative humidity with after exposing 82 hours 22 ℃ times.

(g) high density polyethylene(HDPE), density are 0.960g/cc, and melting index is 0.6g/10min.

(h) new LDPE (film grade), density are 0.917g/cc, and melting index is 0.25g/10min.

Poly(lactic acid) and blend thereof are compared with pure new LDPE (film grade) or high density polyethylene(HDPE) environment degradable very easily.The high density polyethylene(HDPE) sample degradation does not have weightlessness basically, and high density polyethylene(HDPE)-polylactic acid blend has weightlessness, particularly is exposed to the surface of film to poly(lactic acid) with microscopic examination.High density polyethylene(HDPE) exposes under photochemistry light and degrades, and available microscopic examination is arrived.

Make a general survey of all samples, when the percentage composition of poly(lactic acid) rose, before the simulation weathering test and afterwards, tensile strength descended.Adding poly(lactic acid) falls the blend of polypropylene, polystyrene, polyethylene terephthalate and height and new LDPE (film grade) quickly.According to estimates, the hydrolysis of photochemical light and polyester makes polymer degradation.Blend spherical, the uneven zonule of microcosmic must be a poly(lactic acid), they are submerged basically.Thereby the hydrolysis of poly(lactic acid) is slower.Distribution by the control poly(lactic acid) utilizes hydrolysis to degrade quickly.This during again with melt blending the rheology of blend relevant.The inhomogeneous sub-district of dispersive shows that the blended polymkeric substance has consistency.

When the mimic landfill, light is by barrier, and control group and blend all shown extremely slow degradation speed.When at duration of test, the quality of blend does not change, and only is hydrolysis, and the poly(lactic acid) sample is bleached.

On the contrary, in poly(lactic acid), add a small amount of non-degraded thermoplastics and make for example Compatibilized blends of polypropylene, polystyrene, polyethylene terephthalate and height and new LDPE (film grade), can make the degradation speed of poly(lactic acid) slack-off.In the composition, the content of poly(lactic acid) is 80-99% (weight) preferably.

Generally say, the environment degradable composition comprises the mechanical mixture of poly(lactic acid) (polylactide) and the blend of polymkeric substance, this polymkeric substance is selected from the polycondensate of terephthalic acid monoethylene glycol, the polymkeric substance of vinylbenzene, ethene, propylene, vinylchlorid, vinyl-acetic ester, alkyl methacrylate, alkyl acrylate and mechanical mixture thereof or multipolymer.Other possible composition blend is listed in the discussion of following embodiment of the present invention.

Blend is preferably the mechanical mixture and the blend that is selected from polystyrene, polyethylene, polyethylene terephthalate and polyacrylic polymkeric substance of the poly(lactic acid) (n is 75-10,000 integer) of formula I, and other composition is discussed below.Composition is wherein to contain the composition that poly(lactic acid) is 5-50% (weight) preferably.Better composition is that poly(lactic acid) content is 10-20% (weight).

Be selected from above-mentioned polymkeric substance, also can think the polymkeric substance that adds can use or merge use separately.Polymkeric substance is not subjected to above-mentioned restriction, because the polymkeric substance of other type also can be compatible with poly(lactic acid).These polymkeric substance comprise the polymkeric substance and the multipolymer of ethene, propylene, vinylbenzene, vinylchlorid, vinyl-acetic ester, alkyl methacrylate and alkyl acrylate.Will be understood that, comprise the polymkeric substance for preparing by above-mentioned monomeric mixture at this used term multipolymer.In addition, the above-mentioned polymkeric substance and the mechanical mixture of multipolymer also can be applicable to the present invention.

The 3rd embodiment also provides the preparation method for compositions, and this method comprises provides poly(lactic acid); By following selective polymer, the polycondensate of terephthalic acid monoethylene glycol, the polymkeric substance of vinylbenzene, ethene, propylene, vinylchlorid, vinyl-acetic ester, alkyl methacrylate, alkyl acrylate and mechanical mixture thereof and multipolymer; With polymer blending.Blend can be on mill roll melt blending, perhaps use forcing machine chemical combination, or carry out blend with other mechanical means.Be preferably obtain the having general formula poly(lactic acid) of (I).

Also provide the another kind of method for preparing the present composition at this, this method comprises provides a kind of rac-Lactide, and it is selected from D-rac-Lactide, L-rac-Lactide, meso D, L-rac-Lactide, racemize D, L-rac-Lactide and composition thereof; Select a kind of polymkeric substance, it is selected from the polymkeric substance or the multipolymer of vinylbenzene, ethene, terephthalic acid monoethylene glycol, propylene, vinylchlorid, vinyl-acetic ester, alkyl methacrylate, alkyl acrylate and mechanical mixture thereof.Selected rac-Lactide and mixed with polymers also is heated to the rac-Lactide fusion and is partly dissolved polymkeric substance at least.Rac-Lactide has the partially polymerized blend that obtains polylactide at least, and being does not at last have polymeric lactide monomer and selected polymkeric substance.It is the amount of measuring residual lactide that polyreaction is controlled preferably, and stops polyreaction on required degree.If desired, polyreaction can be carried out fully.The amount that additional lactide monomer, lactic acid, rac-Lactide oligopolymer, lactic acid oligomer and composition thereof can prepare pliable and tough thing adds as softening agent, to obtain at the described desired characteristic of the first general embodiment.

According to the mutual solubility of poly(lactic acid) and institute's addition polymerization compound, their ratio can change within a large range, and this is conspicuous to present technique field personnel.Solubleness changes with abundant degree of blended and mixing temperature again.The polymkeric substance of poly(lactic acid) and adding is put into mutual solvent solution can be evenly compatible, and this solvent can not use in many commercial runs.Mechanically mixing is as being easily to implement with mill roll or forcing machine melt blending, but must control it become evenly compatible, just need be required evenly compatible to obtain with high-shear.It also is inconsistent both having made mixed uniformly different polymkeric substance, and just they are divided into sizable non-uniform areas, for example 10-100 micron or bigger.Obtain the blend of " cheese " shape mixture or very poor performance like this.Surprisingly, poly(lactic acid) is easy to compatible with many other polymkeric substance (comprising polarity and non-polar polymer) blend.

The melt blending variable temperaturesization of poly(lactic acid) and other polymkeric substance is with the ratio of the polymkeric substance of regulating poly(lactic acid) and one or more addings.Lesser temps can not obtain suitable solubleness, and the too high mixture that makes again of temperature decomposes.General temperature range is 100-220 ℃, and scope is 130-180 ℃ preferably.The sign that is equal to is the melt viscosity of different polymeric constituents.Along with the increase of molecular weight, viscosity increases sharply.Ratio, temperature, hybrid mode and the time of one or more polymkeric substance by control poly(lactic acid) and adding, and molecular weight, can obtain multiple mixture.For example, poly(lactic acid) can be dispersed in one or more polymkeric substance of adding, otherwise or, and the size of disperse phase and structure can have bigger variation, and can be by the spherical silk of dispersive to different diameter or length.This make they in environment physicals and degradation time in wide variation very.The weight percent of poly(lactic acid) and selected polymkeric substance is 99: 1-1: 99.

Be used to dissolve the polymkeric substance of adding in lactide monomer, then during the rac-Lactide polymerization, mix and the polymeric temperature must be suitable for the mutual cosolvency and the reactivity of rac-Lactide.Comparatively high temps is made generally in the lower molecular weight poly(lactic acid).Another embodiment of the present invention is to mix under a certain temperature, and polymerization under another temperature, to obtain the improvement of disperse phase structure as discussed above.

Can make by fusion preparation method at this composition and to have from the useful article of support structure such as disposable use container, tableware, drum, plate, beverage cup, disposable pallet, syringe, medical basin, packing film or the like.Said composition is useful, and they have the characteristic of common plastics and can replace plastics, go back degraded by environment.The goods that this composition is specially adapted to only disposable use or uses in short-term before processing.

The four-way embodiment:

The 4th embodiment of the present invention comprises elastic and compatible with polylactic acid blend impact modified thing.Compatible all polymkeric substance that are meant of blend can closely mix with poly(lactic acid), discuss as the 3rd general scheme.This mixing can obtain basically blend uniformly.

Environment degradable composition disclosed herein is the component environment degraded at least.The poly(lactic acid) of composition part compared with blend than steady component decompose quite fast, and make the physicals deterioration of blend.For example, when composition be that the deterioration of physicals has been destroyed former preparation product when having the tight and even blend of zonule.The material that this composition can provide environment to be suitable for is because their physical degradation and degraded are more faster than non-degradative plastics commonly used.In addition, because rac-Lactide or oligopolymer that the major part of composition is poly(lactic acid) and/or lactic acid to be made, only remaining small portion is the elastomerics resistates (as block polyester) of degrading more slowly.This resistates has high surface area, and decomposes quickly than bulk product.

Following example has illustrated poly(lactic acid) (PLA) and Hytrel ^TMBlend, Hytrel ^TMBe a kind of block polyester, it is the crystallization hard segment of polybutylene terephthalate and the soft long segmental segmented copolymer of polyether glycol.Poly(lactic acid) and elastomerics are that melting is compatible, and influence its physicals.

The D-rac-Lactide is the dilactide or the cyclic dimer of D-lactic acid.Similarly, the L-rac-Lactide is the cyclic dimer of L-lactic acid.Meso D, L-rac-Lactide are the cyclic dimers of D-and L-lactic acid.Racemize D, L-rac-Lactide are 50/50 mixtures of D-and L-rac-Lactide.When this uses separately, term " D, L-rac-Lactide " is meant and comprises meso D, L-rac-Lactide or racemize D, L-rac-Lactide.Poly(lactic acid) can be by one or more above-mentioned rac-Lactide preparations.

Example 1D:

Do not contain Hytrel ^TMThe polylactide multipolymer of block polyester is to be the method preparation of the example 1B of second kind of general embodiment of 229,939 with serial number, and the notched Izod impact strength of testing it.The results are shown in table 1D.For further comparison, the table 1B of the second general embodiment has listed L-rac-Lactide and D, the notched Izod impact strength of other ratio of L-rac-Lactide.

Example 2D:

In 250 milliliter of three neck round-bottomed flask weighing pack into 10.96 the gram D, the L-rac-Lactide, 108.86 the gram L-rac-Lactides and 5.27 the gram Hytrel ^TM4056 block polyesters (DuPont makes, thermoplastic elastomer).Hytrel ^TM4056 block polyesters are a kind of polyester elastomers, and its hardness is Shore D, low modulus in flexure, and higher melt viscosity, melting index is 7, and proportion is 1.17, and fusing point is 168 ℃, and vicat softening temperature is 112 ℃, extrusion temperature is 171-204 ℃.This flask is equipped with mechanical stirrer and import and export of nitrogen.Inclusion heats with oil bath.Hytrel ^TMBlock polyester is dissolved in the molten lactide under 170 ℃ of temperature.The preparation of catalyst solution is 10 milliliters of stannous octoates to be dissolved in 60 milliliters of toluene, and to distill out 10 milliliters of toluene.100 micro litres of catalyst solution are injected into rac-Lactide and Hytrel ^TMIn the solution of block polyester.This mixture stir about 64 hours under 155 ℃ of temperature and nitrogen.

Viscosity increases immediately, and it is muddy that mixture becomes.Product is tough and opaque.Be moulded the thick film of 0.2-0.23mm 155 ℃ of temperatures, measure tensile property, shown in table 1D.

Be compression molded into the thick plate of 3.2mm, and measure their notched Izod impact strength with 0.9 kilogram pendulum.Outcome record can and not contain Hytrel with data at table 1D ^TMThe similar polylactide multipolymer of the example 1D of block polyester is compared, and table 1D also has the data of so-called medium impact polystyrene (example 7D).

Example 3D:

With 800.0 gram L-rac-Lactides and 202.3 gram racemize D, L-rac-Lactide similar methods with example 2D is used 1.0 milliliters of catalyst solution copolymerizations, does not add Hytrel ^TMSegmented copolymer.Lactide copolymer is transparent and colourless.In another polyreaction, 104.0 gram L-rac-Lactides are with 100 micro litres of catalyst melt polymerizations.Polymkeric substance (L-PLA) is white, crystalline, is easy to crack when meeting when impacting.

Electrically heated two-roller mill machine is heated to 190 ℃, then with 8.4 gram Hytrel ^TMBlock polyester and 19.2 gram L-PLA colligations are on roller.Add 172.4 gram lactide copolymers to this.The very easy blend of this mixture is also removed from roller, compression moulding, and according to the method test of example 2D.The results are shown in table 1D.

Example 4D:

With 80 gram example 3D lactide copolymers, 10 gram example 3DL-PLA and 10 gram Hytrel ^TM4056 block polyesters by the method for previous examples 3D with two rolling grinder blend.Blend is pressed the preceding method test, and outcome record is at table 1D.

Example 5D

The blend of 100 gram example 3D and 20 gram Hytrel ^TMThe further blend of 4056 block polyesters.Mixture is easy to mix on roller, and appearance is very compatible.Measure physicals and be recorded among the table 1D by preceding method.

Example 6D and 7D:

To use crystal polystyrene always and the medium impact polystyrene is tested, be used for the control group of comparison.

The above results clearly illustrates that polylactide can be impact modified.Blend has obviously high notched Izod impact strength compared with the crystal polystyrene of control group, and than the polystyrene of medium impact, its shock strength is lower slightly or identical.Those skilled in the art is not difficult to find out that the impact strength data of table among the 1D can further improve by the consumption and the type of preferred impact modifying agent.

Described in the aforementioned the 3rd general embodiment, because polylactide is compatible with the thermoplastics blend with many other compounds, impact modified polylactide is to belong to polylactide and elastomeric blend compatible blend.The present technique field professional also can learn, it is that opposite with compression molding, because the former often makes orientation of test specimen, shock strength has bigger improvement then because blend is injection molding that the data of table 1D are improved.Table 1D: the physicals of impact modified polylactide relatively

Composition % (weight) notched Izod impact strength

Tensile strength elongation % tangent modulus 0.3m-0.45Kg instance number lactide copolymer L-lactide homopolymers Hytrel ^TM(a) psi (b, c) percent psi/2.5cm (c) 1D 80 (d) 20 07,667 3.4 322,679 0.3-0.4 2D 95.8 (e), 0 4.2 (f) 8,636 3.1 359,409 0.40 3D 86.2 (g), 9.6 4.2 (h) 7,823 3.1 346,502 0.51 4D 80.0 (g) 10.0 10.0 (h)------0.53 5D 71.2 (g) 7.9 20.9 (h)-------0.61 6D (i) 0006,118 3.2 267,245 0.18 7D (j) 0006,090 4---0.7 (a) DoPont makes, Hytrel 4056, thermoplastic polyester elastomer (f) is before 170 ℃ of polymerizations, and Hytrel is dissolved in the lactide monomer.(b) ASTM D882, the 0.18-0.38mm thick film.(f) 80/20 L-D/L-lactide copolymer.(c) compression molding sample.(h) two rolling grinders are 185-190 ℃ of blend.(d) control group, 90/10 L, D-/L-lactide copolymer.(i) control group, crystal polystyrene, melting index is 1.7.(e) 91/9 L-D/L-lactide copolymer.(j) control group, the medium impact polystyrene.

This composition is useful thermoplastics, and available method commonly used such as extrusion molding and compression molding are come melt-processed.

Blend is preferably with the poly(lactic acid) of formula I (n is 75-10,000 integer) and the mechanical mixture that comprises the polymkeric substance of block polyester.Useful composition is that poly(lactic acid) content is the composition of 50-99% (weight).The poly(lactic acid) content of composition is 70-80% (weight) preferably.

Two kinds of embodiments of the general method of preparation composition comprise that (1) is with PLA and the blend compatible polymeric melt blending that can improve shock-resistance such as block polyester, (2) solution blending in the described PLA polymerization process as example 2D, Hytrel in polymerization ^TMBlock polyester is dissolved among the PLA.Used poly(lactic acid) is preferably has general formula I.If desired, softening agent joins in the blend with the amount that can produce pliability, and it is selected from lactide monomer, lactic acid oligomer, lactic acid and composition thereof.Add softening agent and can obtain additional peculiar physical properties, as what in above-mentioned first and second and three general embodiments, discuss.

Hytrel ^TMThe measurement microscope of the mixture of block polyester/poly(lactic acid) shows, dispersive Hytrel ^TMBlock polyester is to exist with several microns or little coccoid zone.The size in this zone is by mixing condition such as blended time, speed and temperature decision.

For example: one or more polymkeric substance that are added in the poly(lactic acid) generally are little heterogeneous zones (less than 10 microns), and are submicroscopic or are dissolved in the poly(lactic acid).In addition, this impact modifying agent must be elastic.

Also do not obtain any concrete theory, but it is believed that the successive substrates that the invention provides poly(lactic acid), this poly(lactic acid) contains the tight mixing microscopic region as the Hytrel block polyester of crackle stagnation agent, because this polyester is the thermoplastic elastomer compatible with poly(lactic acid).

For this purpose, impact modifying agent must be elastic, and combines closely with discontinuous heterogeneous poly(lactic acid).The polymkeric substance that adds is that impact modifying agent should be a thermoplastic elastomer, or crosslinkable rubber, to obtain elastic performance.Such example has natural rubber and styrene-butadiene copolymer.

Test material is placed in the water 5 months, and this material is crisp compared with the material that is not placed in the water.In addition, water becomes tart, shows that poly(lactic acid) fragments into lactic acid.Further illustrate, the degraded that only is poly(lactic acid) is compared with Hytrel ^TMIt is fast that block polyester/poly-lactic acid mixture is wanted.Thereby, Hytrel ^TMBlock polyester also can be used for the slowing down degradation speed of poly(lactic acid).

Adding can with the 3rd component of other component compatibility of above-mentioned discussion, to improve consistency.When the consistency of poly(lactic acid) and impact modifying agent is relatively poor, can adds the 3rd component and improve consistency.When the 3rd component can be compatible respectively with other two component, and this two component (poly(lactic acid) and impact modifying agent) will add the 3rd component when can not be fine compatible usually.Do like this and can improve mutually combining between poly(lactic acid) and elastic impact modifying agent.But what come in and go out expectation is that poly(lactic acid) and other type polymer (comprising polarity and nonpolar) have consistency in a big way.This can consult the 3rd general embodiment.

Composition at this can be made useful goods such as container, tableware, tray, plate, beverage cup, disposable use dish, syringe, medical basin or the like with the melt-processed method.Said composition is specially adapted to disposable goods, or the goods that use in short-term before discarded.

Above-mentioned various specific exampless and the embodiment discussed of the present invention should be appreciated that example and embodiment that the present invention should not be illustrated limit, and in the scope of claim below multiple variation can be arranged.

Claims (16)

1. the composition that can degrade in environment comprises the mechanical mixture of following each component:

A. poly(lactic acid),

B. be selected from the polymkeric substance of ethylene glycol terephthalate polymkeric substance, vinylbenzene, ethene, propylene, vinylchlorid, vinyl-acetic ester, alkyl methacrylate, alkyl acrylate or the polymkeric substance of multipolymer and their mechanical mixture.

2. by the composition of claim 1, wherein the weight ratio of poly(lactic acid) and selected polymkeric substance is between 99: 1 to 1: 99.

3. prepare claim 1 method for compositions, comprising:

A., poly(lactic acid) is provided,

B. from the ethylene glycol terephthalate polymkeric substance, the polymkeric substance of vinylbenzene, ethene, propylene, vinylchlorid, vinyl-acetic ester, alkyl methacrylate, alkyl acrylate or multipolymer, and choose polymkeric substance in their mechanical mixture,

C. blend step (a) and polymkeric substance (b).

4. by the composition of claim 1, wherein contain and be selected from D-rac-Lactide, L-rac-Lactide, meso D, the softening agent of L-rac-Lactide, lactic acid, rac-Lactide oligopolymer, lactic acid oligomer and their mixture.

5. the composition that can degrade in environment comprises the blend of being made up of the mechanical mixture of following each component:

A. poly(lactic acid),

B. the blend compatible polymers that can improve the poly(lactic acid) impact resistance.

6. by the composition of claim 5, wherein poly(lactic acid) accounts for the 50-99% (weight) of said composition.

7. by the composition of claim 5, wherein blend compatible polymers is a block polyester.

8. by the composition of claim 7, wherein blend compatible polymers is polybutylene terephthalate crystallization hard segment and polyether glycol Great Wall Software segmental segmented copolymer.

9. prepare the method for compositions of claim 5, comprising:

A., poly(lactic acid) is provided,

B. select to improve the blend compatible polymeric of shock-resistance,

C. blend step (a) and polymkeric substance (b).

10. by the method for claim 9, wherein select block polyester for use.

11., wherein select segmented copolymer or natural rubber and the styrene-butadiene copolymer formed by polybutylene terephthalate crystallization hard segment and polyether glycol Great Wall Software segment for use by the method for claim 9.

12. the method for compositions of preparation claim 5 comprises:

A. one or more are selected from D-rac-Lactide, L-rac-Lactide, D, the rac-Lactide of L-rac-Lactide and composition thereof mixes mutually with a kind of blend compatible polymers that is changing impact resistance that can provide,

B. heating and this blend compatible polymers is dissolved in the rac-Lactide of step (a) forms a kind of solution,

C. the rac-Lactide in this solution of polymerization.

13. the method by claim 12 comprises by melt-processed above-mentioned composition is processed into useful form.

14. the method by claim 12 comprises and selects the blend compatible polymers that contains block polyester for use.

15., comprise from segmented copolymer, natural rubber and the styrene-butadiene copolymer formed by polybutylene terephthalate crystallization hard segment and polyether glycol Great Wall Software segment or its mixture and select the blend compatible polymers for use by the method for claim 12.

16. the method by claim 5 comprises:

E. add softening agent in this blend, described softening agent is selected from lactide monomer, rac-Lactide oligopolymer, lactic acid oligomer, lactic acid and their mixture.

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