CN103668541A - Degradable fibers containing PBAT (poly(butylene adipate-co-terephthalate)) and preparation method thereof - Google Patents

Abstract

The invention relates to a degradable fiber containing PBAT and a preparation method thereof, which is made of the following components by weight: 30-90 parts of polyadipate/butylene terephthalate (PBAT), polymerized 10-70 parts of the product; vacuum-dry the poly(butylene adipate/terephthalate) and the high molecular weight polymer until the water content is below 100ppm, and mix them in proportion to carry out melt spinning, and cooling, winding and forming, The pre-drawn filaments of degradable fibers containing PBAT were obtained. Compared with the prior art, the fiber obtained by the present invention has better spinnability, higher mechanical strength and continuous and stable soft hand feeling, and has a wide range of application fields. At the same time, the preparation method of the present invention is simple and easy to operate. The spinning equipment can be industrially produced without equipment modification, which saves costs.

Description

A kind of degradable fiber containing PBAT and preparation method thereof

technical field

The invention relates to a degradable fiber in the technical field of polymer materials and a preparation method thereof, in particular to a degradable fiber containing PBAT and a preparation method thereof.

Background technique

Among the degradable materials, polybutylene adipate/terephthalate (PBAT) is a terpolymer of terephthalic acid, adipic acid and butanediol, which is easy to process, has strong toughness and good Biodegradability, decomposes into carbon dioxide, biomass and water under soil or compost conditions, and other properties are similar to low-density polyethylene. At the same time, PBAT fiber material has good biodegradability, softer hand feeling than PLA and other fiber materials, good elasticity, good heat resistance, and high temperature resistance than ordinary materials. These advantages determine its broad application prospects. However, since the synthesis process of PBAT adopts random copolymerization, it is not easy to crystallize, which restricts the development of PBAT fiber preparation technology and the application of PBAT as a fiber material. Therefore, using PBAT as a raw material to prepare a degradable fiber that meets the requirements of environmental protection and sustainable development can expand its application field and has important market significance.

Chinese patent CN 101760796A introduces a method for making PBT high elastic yarn. The strength of the fiber obtained by this method is 30.91-35.52cN/tex, the elongation is 30-60%, and it has excellent elongation elastic recovery rate. And the characteristics of soft and easy to dye. However, its spinning temperature is high and it is prone to thermal degradation. Kan Ruijun used PBAT to change the crystal form of PHBV. The PHBV/PBAT blend has a wider processing window than pure PHBV, which broadens its melt spinnability, but the effect of the blend's melt-blown non-woven fabric is not good. , to be further improved (Donghua University, Master Thesis, 2010). Qi Zhonghua used electrospinning technology to prepare ultrafine fiber mats of PHBV/Ecoflex (PBAT) blend system, and analyzed the effect of the addition of Ecoflex on the average diameter and diameter distribution of electrospun fibers, but PHBV needs to be configured before spinning /Ecoflex/dichloromethane solution, the process is more complicated (Synthesis Technology and Application, 2008).

In view of the above problems, the present invention adopts PBAT to blend with other macromolecular materials to carry out melt spinning, wherein, the molecular weight of the linear polyester used for spinning is high, and when the distribution is relatively uniform, the performance of the fiber obtained is better, and in The cooling distance is lengthened during the spinning process, thus effectively improving the problem that PBAT is not easy to cool and easy to stick during the spinning process. At the same time, the process is simple and easy, which can improve the performance of the PBAT fiber and effectively broaden the application field of the PBAT fiber material.

Contents of the invention

The purpose of the present invention is to provide a PBAT-containing degradable fiber with good spinnability, high mechanical strength and continuous and stable soft hand feeling and its preparation method in order to overcome the above-mentioned defects in the prior art.

The purpose of the present invention can be achieved through the following technical solutions:

A kind of degradable fiber containing PBAT is made of components comprising the following parts by weight:

Polybutylene adipate/terephthalate (PBAT) 30-90 parts

High molecular polymer 10-70 parts.

The polybutylene adipate/terephthalate has a melting point of 110-160° C., a thermal decomposition temperature higher than 300° C., a weight-average molecular weight of 40,000-120,000, and a molecular weight dispersion of 1.5-3.

The melting point of the polybutylene adipate/terephthalate is preferably 130-150° C., the weight-average molecular weight is preferably 8-100,000, and the molecular weight dispersion is preferably 2-2.5.

Described macromolecular polymer is selected from the one in polyhydroxybutyric acid (PHB), polyhydroxybutyrate-valerate (PHBV), polybutylene succinate (PBS) or polylactic acid (PLA) or two.

The weight average molecular weight of the polyhydroxybutyric acid is 70,000 to 300,000, the weight average molecular weight of the polyhydroxybutyrate-valerate is 100,000 to 400,000, and the polybutylene succinate The weight average molecular weight is 90,000 to 150,000, and the weight average molecular weight of the polylactic acid is 60,000 to 160,000.

A preparation method of degradable fiber containing PBAT, the method comprises the following steps:

(1) Vacuum drying the poly(butylene adipate/terephthalate) and polymer until the moisture content is below 100ppm;

(2) The dried polybutylene adipate/terephthalate and high molecular weight polymer are mixed in proportion to carry out melt spinning, and cooling, coiling and forming, directly obtain the preform of the degradable fiber containing PBAT Draw wire.

In this method, after mixing the dried polybutylene adipate/terephthalate and the high molecular weight polymer in proportion, melt blending, extruding, and granulating with a twin-screw extruder to obtain blended granules and then vacuum-dry the blended particles until the moisture content is below 100ppm, then melt-spin, cool, and roll into shape to obtain pre-drawn filaments of degradable fibers containing PBAT.

The time of the vacuum drying is 24-48 hours, the temperature of the vacuum drying is 70-100°C, the temperature of the melt-spinning is 180-245°C, and the cooling is extended distance cooling, the cooling distance The winding speed is 3-5m, and the winding speed is 500-1500m/min.

The melt spinning adopts a screw-type spinning machine.

The extruding temperature is 170-220° C., and the screw speed of the twin-screw extruder is 100-500 rpm.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

Compared with ordinary PBAT fibers, the fibers obtained by the present invention have better spinnability, higher mechanical strength, and continuous and stable soft hand feeling, so their application fields can be expanded and widely used in textile and other fields. At the same time, the preparation method of the present invention is simple and easy to operate, and the general spinning equipment can be industrially produced without equipment modification, which saves costs. In the present invention, the performance of the PBAT fiber is improved by adding a high molecular polymer, and the method of lengthening the cooling distance is adopted to effectively improve the problem of thread sticking in the spinning process, and obtain a fiber material with good performance.

Description of drawings

Figure 1 is a schematic structural view of a screw-type spinning machine.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1

(1) Polybutylene terephthalate-butylene adipate (PBAT, with a weight-average molecular weight of 100,000), polyhydroxybutyrate-valerate (PHBV, with a weight-average molecular weight of 300,000) and The particles of polylactic acid (PLA, with a weight average molecular weight of 80,000) were vacuum-dried until the water content was 100 ppm, the drying temperature was 95° C., and the drying time was 30 h.

(2) Take 47 parts of PBAT after drying, 45 parts of PLA and 8 parts of PHBV and mix them with a twin-screw extruder to melt and blend, extrude and granulate to make master batches. The extrusion temperature is 180 °C and the screw speed 300rpm.

(3) Dry the masterbatch until the moisture content reaches 100ppm, and process through melting, extruding, filtering, and metering of the hopper 1, screw 2, box 3, and metering pump 4 in the screw-type spinning machine shown in Figure 1 , extruded from the spinneret 5, extended distance 6 after cooling, through the cluster oiling device 7 and winding roller 8, to obtain the degradable fiber containing PBAT.

Among them, the spinning temperature is 190°C, the temperature of zone I/II/III/IV is 180/190/190/190°C respectively, the temperature of the box is 190°C, the temperature of the pipeline is 190°C, and the temperature of the metering pump is 190°C , the winding speed is 800m/min, the cooling distance is 3m, the strength of the obtained fiber is 1.5cN/tex, the elongation is 69%, and the hand feels soft. After being placed at room temperature for a week, the hand feel is still soft.

Example 2

(1) Polybutylene terephthalate-butylene adipate (PBAT, with a weight-average molecular weight of 120,000), polyhydroxybutyrate-valerate (PHBV, with a weight-average molecular weight of 200,000) particles Carry out vacuum drying until the water content is 100ppm, the drying temperature is 80°C, and the drying time is 48h.

(2) After getting 30 parts of PBAT after drying, the PHBV of 70 parts mixes through hopper 1 in the screw type spinning machine as shown in Figure 1, screw rod 2, casing 3, the melting of metering pump 4, extrusion, Filtration, metering treatment, extruding from spinneret 5, lengthening distance 6 and cooling, passing through cluster oiling device 7 and winding roller 8 to obtain degradable fibers containing PBAT.

Among them, the spinning temperature is 200°C, the temperature of zone I/II/III/IV is 190/200/200/200°C respectively, the temperature of the box is 200°C, the temperature of the pipeline is 200°C, and the temperature of the metering pump is 200°C , the winding speed is 1200m/min, the cooling distance is 4m, the strength of the obtained fiber is 1.1cN/tex, the elongation is 92%, the hand feel is soft, and after being placed at room temperature for a week, the hand feel is still soft.

Example 3

(1) Polybutylene terephthalate-butylene adipate (PBAT, weight-average molecular weight is 60,000), polybutylene succinate (PBS, weight-average molecular weight is 100,000) particles Vacuum-dry until the water content is 100ppm, the drying temperature is 85°C, and the drying time is 40h.

(2) After mixing 90 parts of PBAT and 10 parts of PBS after drying, they are melted, extruded, filtered and metered through hopper 1, screw 2, casing 3 and metering pump 4, extruded from spinneret 5, After lengthening the distance 6 and cooling, the degradable fiber containing PBAT is obtained through the clustering and oiling device 7 and the winding roller 8 .

Among them, the spinning temperature is 245°C, the temperature of zone I/II/III/IV is 235/245/245/245°C respectively, the box temperature is 245°C, the pipeline temperature is 245°C, and the metering pump temperature is 245°C , the winding speed is 1500m/min, the cooling distance is 3.5m, the fiber strength is 1.2cN/tex, the elongation is 84%, and the hand feel is soft.

Example 4

(1) Polybutylene terephthalate-butylene adipate (PBAT, weight-average molecular weight is 100,000) and polylactic acid (PLA, weight-average molecular weight is 120,000) particles are vacuum-dried until moisture It is 100ppm, the drying temperature is 95°C, and the drying time is 28h.

(2) After mixing 65 parts of PBAT and 35 parts of PLA pellets after drying, they were melt-blended with a twin-screw extruder, extruded and granulated to make master batches. The extrusion temperature was 170°C and the screw speed was 100rpm.

(3) Then the masterbatch is dried until the moisture content reaches 100ppm, melted, extruded, filtered, and metered by the hopper 1, the screw 2, the box body 3, and the metering pump 4, and then extruded from the spinneret 5 to extend the distance 6 After cooling, the degradable fibers containing PBAT are obtained through the bundle oiling device 7 and the winding roller 8 .

Among them, the spinning temperature is 210°C, the temperature in zone I/II/III/IV is 200/210/210/210°C respectively, the box temperature is 210°C, the pipeline temperature is 210°C, and the metering pump temperature is 210°C , The winding speed is 1000m/min, the cooling distance is 4m, the fiber strength is 1.4cN/tex, the elongation is 78%, and the hand feel is soft.

Example 5

(1) Polybutylene terephthalate-butylene adipate (PBAT, with a weight average molecular weight of 40,000), polylactic acid (PLA, with a weight average molecular weight of 60,000) and polybutylene succinate Alcohol ester (PBS, weight-average molecular weight: 90,000) granules were vacuum-dried until the water content was 100 ppm, the drying temperature was 85° C., and the drying time was 30 h.

(2) Take the dried 40 parts of PBAT, 40 parts of PLA and 20 parts of PBS granules and mix them with a twin-screw extruder to melt and blend, extrude and granulate to make masterbatches. The extrusion temperature is 190 °C and the screw speed 500rpm.

(3) Then the masterbatch is dried until the moisture content reaches 100ppm, melted, extruded, filtered, and metered by the hopper 1, the screw 2, the box body 3, and the metering pump 4, and then extruded from the spinneret 5 to extend the distance 6 After cooling, the degradable fibers containing PBAT are obtained through the bundle oiling device 7 and the winding roller 8 .

Among them, the spinning temperature is 220°C, the temperature of zone I/II/III/IV is 210/220/220/220°C respectively, the box temperature is 220°C, the pipeline temperature is 220°C, and the metering pump temperature is 220°C , the winding speed is 500m/min, the cooling distance is 3.5m, the fiber strength is 1.7cN/tex, the elongation is 53%, and the hand feel is soft.

Example 6

(1) Polybutylene terephthalate-butylene adipate (PBAT, weight-average molecular weight is 90,000), polyhydroxybutyric acid (PHB, weight-average molecular weight is 170,000) particles are vacuum-dried, Until the water content is 100ppm, the drying temperature is 80°C, and the drying time is 48h.

(2) After mixing 70 parts of PBAT and 30 parts of PHB after drying, they are melted, extruded, filtered and metered through hopper 1, screw 2, casing 3 and metering pump 4, extruded from spinneret 5, After lengthening the distance 6 and cooling, the degradable fiber containing PBAT is obtained through the clustering and oiling device 7 and the winding roller 8 .

Among them, the spinning temperature is 230°C, the temperature of zone I/II/IN/IV is 220/230/230/230°C respectively, the temperature of the box is 230°C, the temperature of the pipeline is 230°C, and the temperature of the metering pump is 230°C , the winding speed is 900m/min, the cooling distance is 4.5m, the fiber strength is 1.3cN/tex, the elongation is 77%, and the hand feel is soft.

Example 7

A kind of degradable fiber containing PBAT is made of components comprising the following parts by weight:

Polybutylene adipate/terephthalate (PBAT) 30 parts

High molecular polymer 70 parts.

Among them, polybutylene adipate/terephthalate has a melting point of 110° C., a thermal decomposition temperature higher than 300° C., a weight average molecular weight of 80,000, and a molecular weight dispersion of 1.5.

The polymer is a mixture of polyhydroxybutyrate (PHB) and polyhydroxybutyrate-valerate (PHBV), each accounting for 35 parts. Wherein the weight average molecular weight of polyhydroxybutyric acid is 70,000, and the weight average molecular weight of polyhydroxybutyrate-valerate is 100,000.

A preparation method of degradable fiber containing PBAT, the method comprises the following steps:

(1) Vacuum drying the poly(butylene adipate/terephthalate) and polymer until the moisture content is below 100ppm;

(2) mixing the dried polybutylene adipate/terephthalate and high molecular weight polymer in proportion, melt blending, extruding and granulating with a twin-screw extruder to obtain blended granules;

(3) Dry the blended particles obtained in step (2) until the moisture content is below 100ppm, and then use a screw-type spinning machine to carry out melt spinning, and cooling, winding and forming, to obtain the pre-drawing of the degradable fiber containing PBAT Silk.

The time of step (1) vacuum drying is 24 hours, and the temperature of vacuum drying is 100°C; the temperature of step (2) extrusion is 220°C, and the rotating speed of the screw is 500rpm; the temperature of step (3) melt spinning is 180°C , the cooling is extended distance cooling, the cooling distance is 3m, and the winding speed is 500m/min. The strength of the obtained fiber is 1.2cN/tex, the elongation is 80%, and the handle is soft.

Example 8

A kind of degradable fiber containing PBAT is made of components comprising the following parts by weight:

Polybutylene adipate/terephthalate (PBAT) 90 parts

Polymer 10 parts.

Among them, polybutylene adipate/terephthalate has a melting point of 130°C, a thermal decomposition temperature higher than 300°C, a weight average molecular weight of 80,000, and a molecular weight dispersion of 2.

The polymer is a mixture of polyhydroxybutyric acid (PHB) and polylactic acid (PLA), each accounting for 5 parts. Among them, the weight average molecular weight of polyhydroxybutyric acid is 300,000, and the weight average molecular weight of polylactic acid is 160,000.

A preparation method of degradable fiber containing PBAT, the method comprises the following steps:

(1) Vacuum drying the poly(butylene adipate/terephthalate) and polymer until the moisture content is below 100ppm;

(2) The dried polybutylene adipate/terephthalate and high molecular weight polymer are mixed in proportion to carry out melt spinning, and cooling, coiling and forming, directly obtain the preform of the degradable fiber containing PBAT Draw wire.

Melt spinning uses a screw type spinning machine.

The time of step (1) vacuum drying is 48 hours, and the temperature of vacuum drying is 70 DEG C. The temperature of step (2) melt spinning is 180 DEG C, and cooling is to adopt extended distance cooling, and the distance of cooling is 5m, and the speed of coiling is 1500m/min. The strength of the obtained fiber is 1.4cN/tex, the elongation is 91%, and the hand feeling is soft.

Example 9

A kind of degradable fiber containing PBAT is made of components comprising the following parts by weight:

Polybutylene adipate/terephthalate (PBAT) 50 parts

Polymer 50 parts.

Among them, polybutylene adipate/terephthalate has a melting point of 150° C., a thermal decomposition temperature higher than 300° C., a weight average molecular weight of 100,000, and a molecular weight dispersion of 2.5.

The polymer is a mixture of polyhydroxybutyrate-valerate (PHBV) and polybutylene succinate (PBS), each accounting for 25 parts. Among them, the weight average molecular weight of polyhydroxybutyrate-valerate is 400,000, and the weight average molecular weight of polybutylene succinate is 150,000.

A preparation method of degradable fiber containing PBAT, the method comprises the following steps:

(1) Vacuum drying the poly(butylene adipate/terephthalate) and polymer until the moisture content is below 100ppm;

(2) mixing the dried polybutylene adipate/terephthalate and high molecular weight polymer in proportion, melt blending, extruding and granulating with a twin-screw extruder to obtain blended granules;

(3) Dry the blended particles obtained in step (2) until the moisture content is below 100ppm, and then use a screw-type spinning machine to carry out melt spinning, and cooling, winding and forming, to obtain the pre-drawing of the degradable fiber containing PBAT Silk.

The time of step (1) vacuum drying is 48 hours, and the temperature of vacuum drying is 70°C; the temperature of step (2) extrusion is 170°C, and the rotating speed of the screw is 400rpm; the temperature of step (3) melt spinning is 180°C , the cooling is extended distance cooling, the cooling distance is 4.5m, and the winding speed is 1000m/min. The obtained fiber has a strength of 1.2cN/tex, an elongation of 71%, and a soft hand.

Example 10

A kind of degradable fiber containing PBAT is made of components comprising the following parts by weight:

Polybutylene adipate/terephthalate (PBAT) 60 parts

High molecular polymer 40 parts.

Among them, polybutylene adipate/terephthalate has a melting point of 160°C, a thermal decomposition temperature higher than 300°C, a weight average molecular weight of 80,000, and a molecular weight dispersion of 3.

The high molecular polymer is selected from polyhydroxybutyric acid (PHB). Wherein, the weight average molecular weight of polyhydroxybutyric acid is 200,000.

A preparation method of degradable fiber containing PBAT, the method comprises the following steps:

(1) Vacuum drying the poly(butylene adipate/terephthalate) and polymer until the moisture content is below 100ppm;

(2) The dried polybutylene adipate/terephthalate and high molecular weight polymer are mixed in proportion to carry out melt spinning, and cooling, coiling and forming, directly obtain the preform of the degradable fiber containing PBAT Draw wire.

Among them, a screw type spinning machine is used for the melt spinning. The time of step (1) vacuum drying is 24 hours, and the temperature of vacuum drying is 100°C; the temperature of step (2) melt spinning is 245°C, and the cooling is to adopt extended distance cooling, the cooling distance is 5m, and the winding speed It is 800m/min. The obtained fiber has a strength of 1.1cN/tex, an elongation of 87%, and a soft hand.

Comparative example 1

(1) The particles of polybutylene terephthalate-adipate (PBAT, with a weight average molecular weight of 80,000) were vacuum-dried until the moisture content was 100 ppm, the drying temperature was 80° C., and the drying time was 24 hours.

(2) The dried PBAT is melted, extruded, filtered, and metered through the hopper 1, the screw 2, the box body 3, and the metering pump 4, extruded from the spinneret 5, cooled by the extended distance 6, and passed through the cluster Oil device 7 and winding roll 8 to obtain PBAT degradable fibers.

Among them, the spinning temperature is 240°C, the temperature of zone I/II/III/IV is 230/240/240/240°C respectively, the box temperature is 240°C, the pipeline temperature is 240°C, and the metering pump temperature is 240°C , the winding speed is 1000m/min, the cooling distance is 4m, the fiber strength is 0.78eN/tex, the elongation is 237%, and the hand feel is soft. Its strength is 0.78cN/tex and its elongation is 237%. During the spinning process, bonding and broken filaments occur, and the strength of the resulting fiber is poor.

Comparative example 2

(1) Polybutylene terephthalate-5-dioic acid butylene glycol ester (PBAT, weight-average molecular weight is 80,000) and polybutylene succinate (PBS, weight-average molecular weight is 120,000) Vacuum drying to 100ppm moisture, drying temperature is 90°C, and drying time is 30h.

(2) After mixing 95 parts of PBAT and 5 parts of PBS after drying, they were melt-blended with a twin-screw extruder, extruded and granulated to make master batches. The extrusion temperature was 180° C., and the screw speed was 200 rpm.

(3) Then the masterbatch is dried until the moisture content reaches 100ppm, melted, extruded, filtered, and metered by the hopper 1, the screw 2, the box body 3, and the metering pump 4, and then extruded from the spinneret 5 to extend the distance 6 After cooling, the degradable fibers containing PBAT are obtained through the bundle oiling device 7 and the winding roller 8 .

Among them, the spinning temperature is 220°C, the temperature of zone I/II/III/IV is 210/220/220/220°C respectively, the box temperature is 220°C, the pipeline temperature is 220°C, and the metering pump temperature is 220°C , the winding speed is 900m/min, the cooling distance is 3.5m, the fiber strength is 0.71cN/tex, the elongation is 241%, and the hand feel is soft. Because the amount of PBS added is too small, and after two melting processes, the spinnability decreases and the phenomenon of broken filaments occurs.

Comparative example 3

(1) Polylactic acid (PLA, with a weight-average molecular weight of 80,000) was vacuum-dried until the moisture content was 100 ppm, the drying temperature was 100° C., and the drying time was 32 hours.

(2) The dried PLA is melted, extruded, filtered, and metered through the hopper 1, the screw 2, the box body 3, and the metering pump 4, extruded from the spinneret 5, cooled by the extended distance 6, and passed through the cluster Oil device 7 and winding roll 8 to obtain PLA fibers.

Among them, the spinning temperature is 250°C, the temperature of zone I/II/III/IV is 240/250/250/250°C respectively, the box temperature is 250°C, the pipeline temperature is 250°C, and the metering pump temperature is 250°C , the winding speed is 1000m/min, the cooling distance is 5m, the strength of the obtained fiber is 2.35cN/tex, and the elongation is 89%. The PLA fiber is inelastic and hard, which limits its application field.

According to the results of the above examples and comparative examples, the degradable fiber containing PBAT obtained in the present invention has a strength ≥ 1.1 eN/dtex and an elongation of 70-100%. When the cooling distance is lengthened, it can effectively improve the sticking problem in the spinning process. At the same time, PBAT has good elasticity and heat resistance. Blending with other degradable polymer materials for spinning can not only improve the blending fiber Performance, and the obtained PBAT-containing fiber feels soft and still has degradability.

Claims (10)

1. containing a biodegradable fiber of PBAT, it is characterized in that, by the component that comprises following weight portion, made:

Poly-adipic acid/butylene terephthalate (PBAT) 30-90 part

High molecular polymer 10-70 part.

2. a kind of biodegradable fiber containing PBAT according to claim 1, it is characterized in that, the fusing point of described poly-adipic acid/butylene terephthalate is 110～160 ℃, and heat decomposition temperature is higher than 300 ℃, weight average molecular weight is 4～120,000, and molecular weight dispersity is 1.5～3.

3. a kind of biodegradable fiber containing PBAT according to claim 2, is characterized in that, the fusing point of described poly-adipic acid/butylene terephthalate is preferably 130～150 ℃, and weight average molecular weight is preferably 8～100,000, and molecular weight dispersity is preferably 2～2.5.

4. a kind of biodegradable fiber containing PBAT according to claim 1, is characterized in that, described high molecular polymer is selected from one or both in poly butyric, poly butyric-valerate, poly butylene succinate or PLA.

5. a kind of biodegradable fiber containing PBAT according to claim 4, it is characterized in that, the weight average molecular weight of described poly butyric is 7～300,000, the weight average molecular weight of described poly butyric-valerate is 10～400,000, the weight average molecular weight of described poly butylene succinate is 9～150,000, and the weight average molecular weight of described PLA is 6～160,000.

6. a preparation method for the biodegradable fiber containing PBAT as described in as arbitrary in claim 1～5, is characterized in that, the method comprises the following steps:

(1) will gather adipic acid/butylene terephthalate and high molecular polymer vacuumize to moisture is below 100ppm;

(2) carry out melt spinning after dried poly-adipic acid/butylene terephthalate is mixed in proportion with high molecular polymer, and cooling, around roll forming, directly obtain the preliminary draft silk containing the biodegradable fiber of PBAT.

7. the preparation method of a kind of biodegradable fiber containing PBAT according to claim 6, it is characterized in that, after the method can also be mixed dried poly-adipic acid/butylene terephthalate with high molecular polymer in proportion, with double screw extruder melt blending, extrude, granulation, obtain blended particles; By blended particles vacuumize to moisture, be to carry out melt spinning after below 100ppm again, and cooling, around roll forming, obtain the preliminary draft silk containing the biodegradable fiber of PBAT.

8. according to the preparation method of a kind of biodegradable fiber containing PBAT described in claim 6 or 7, it is characterized in that, the described vacuum drying time is 24～48 hours, vacuum drying temperature is 70～100 ℃, the temperature of described melt spinning is 180～245 ℃, described being cooled to adopts lengthening distance cooling, and cooling distance is 3～5m, and the speed of coiling is 500～1500m/min.

9. according to the preparation method of a kind of biodegradable fiber containing PBAT described in claim 6 or 7, it is characterized in that, described melt spinning adopts screw type spinning machine.

10. the preparation method of a kind of biodegradable fiber containing PBAT according to claim 7, is characterized in that, the described temperature of extruding is 170～220 ℃, and the rotating speed of the screw rod of double screw extruder is 100～500rpm.