CN109575545A - A kind of fiber/polyurethane/polylactic acid blend and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of fiber/polyurethane/polylactic acid blends and preparation method thereof.The fiber/polyurethane/polylactic acid blend is made of polyester-type thermoplastic polyurethane, polylactic acid and fiber, and the dosage of the fiber is the 10-30% of polyester-type thermoplastic polyurethane and polylactic acid quality sum；It wherein, is in terms of 100% by the quality sum of polyester-type thermoplastic polyurethane and polylactic acid, mass ratio shared by the polyester-type thermoplastic polyurethane is 5-20%, and surplus is polylactic acid；Wherein: polyester-type thermoplastic polyurethane is the polyester-type thermoplastic polyurethane of undefined structure, and by mass percentage, soft segment accounts for the 75-90% of polyester-type thermoplastic polyurethane quality, and surplus is hard section.Compared with pure polylactic acid, blend of the present invention significantly reduces its glass transition temperature while significantly improving elongation at break and tensile strength.

Description

A kind of fiber/polyurethane/polylactic acid blend and preparation method thereof

Technical field

The present invention relates to a kind of modified polylactic acid materials, and in particular to a kind of fiber/polyurethane/polylactic acid blend and its Preparation method.

Background technique

The problem of bringing with " white garbage " and conventional plastic to petroleum resources shortage and environmental pollution gets worse, The demand of biodegradable plastics increasingly increases.Polylactic acid (PLA) is because of its good processability, mechanical performance, the transparency, former material The sufficient outstanding features such as renewable in material source and be considered as most promising biodegradable plastic.However polylactic acid table The high brittleness revealed, which becomes, limits its widely applied maximum obstruction.It is many in order to improve the brittleness of polylactic acid, improve its toughness Enterprise and scientific research institutions have carried out a large amount of study on the modification to polylactic acid.

Currently, the brittlement modified method of polylactic acid mainly has addition small molecule plasticizer, is blended with flexible material, but report All there is the tensile strength that material is substantially reduced while carrying out toughening modifying to polylactic acid in many methods in road and vitrifying turns The deficiency of temperature.In document " performance study of several plasticizer to polylactic acid ", respectively using polyethylene glycol (PEG), neighbour Dioctyl phthalate (DOP), tributyl citrate (TBC), triphenyl phosphite (TPPi), dibutyl sebacate (DBS) are right Polylactic acid is plasticized, experimental result show these types of plasticizer the elongation at break for significantly improving polylactic acid simultaneously, Significantly reduce polylactic acid tensile strength and glass transition temperature (Zhang Yongwei etc., modern plastics processed and applied, 2007 The phase of volume 19 the 6th, p38-40).On the other hand, small molecule plasticizer the problems such as there is also migration precipitations simultaneously, and small molecule is plasticized The precipitation of agent can further result in the decline of the mechanical property of material.As " plasticizer is to P (3HB-co-4HB) mechanical property for document Influence research " in P (3HB-co-4HB) is increased using the small molecules plasticizer such as epoxidized soybean oil, acetic acid tributyl citrate Modeling, after placing one month the tensile strength of sample and elongation at break decrease (blue small equality, plastics industry, 2010 years Volume 38 supplementary issue S0, p124-127).

The problem of small molecule plasticizer is then not present using macromolecular plasticizer, but most of macromolecular plasticizer is also It is to equally exist the problem of causing the performances such as tensile strength of material to be decreased obviously.Such as the document " system of biaxially stretched polylactic acid film It is standby " in using poly- butylene carbonate to polylactic acid carry out toughening modifying, when the content of poly- butyl carbonate be 20% when, polylactic acid Tensile strength has dropped 43%, and (Luo Zhuoxin, master thesis, Guangzhou: South China Science & Engineering University is specifically shown in document p34, table 4- 6).For another example, it is prepared in document " mechanical behavior of Polylactic acid/polyurethane blend and morphological research " using double screw extruder A series of polylactic acid (PLA)/thermoplastic polyurethane (TPU) blend by universal testing machine, radial-boom impact tester and are moved State Mechanical Analyzer carries out Mechanics Performance Testing to PLA/TPU blend, and to the sample under different stretch state and impacts disconnected Face is scanned electron microscope observation respectively.The result shows that the fracture of PLA/TPU blend is stretched with the increase of TPU content Long rate and impact strength significantly increase, and storage modulus reduces, and loss modulus increases, and it is thick that Tensile fracture shows droplet form- The differentiation of the thin fine state of fine state-；When TPU content reaches 40% (mass fraction, similarly hereinafter), the extension at break of PLA/TPU blend Rate and impact strength increase 300% and 13.5 times (Jia Shikui etc., Chinese Plastics, 03 phase in 2017) than pure PLA respectively.But It is that, when the content of polyurethane is 20%, the elongation at break of polylactic acid increases only 3.3 times, and tensile strength reduces 33% (specifically see Section 2.1 of document), toughening result is obviously not ideal enough.

Therefore, it is necessary to which elongation at break and tensile strength can be significantly improved by providing one kind, and significantly reduce its glass The modified polylactic acid material of glass transition temperature.

Summary of the invention

The technical problem to be solved in the present invention is to provide one kind can significantly improve resulting materials elongation at break and stretching While intensity, and significantly reduce fiber/polyurethane/polylactic acid blend and its preparation side of its glass transition temperature Method.

Fiber of the present invention/polyurethane/polylactic acid blend, it is characterised in that: the blend is by polyester-type thermoplastic Property polyurethane, polylactic acid and fiber constitute, the dosage of the fiber is polyester-type thermoplastic polyurethane and polylactic acid quality sum 10-30%；It wherein, is the polyester-type thermoplastic in terms of 100% by the quality sum of polyester-type thermoplastic polyurethane and polylactic acid Property polyurethane shared by mass ratio be 5-20%, surplus is polylactic acid；Wherein:

The polyester-type thermoplastic polyurethane is the polyester-type thermoplastic polyurethane of undefined structure, the polyester-type thermoplastic Property polyurethane is made of soft segment and hard section, and in the composition of polyester-type thermoplastic polyurethane, by mass percentage, soft segment accounts for poly- The 75-90% of ester type thermoplastic polyurethane quality, surplus are hard section；Wherein, it is the poly- of 1000-2500 that soft segment, which is number-average molecular weight, Ester polyol, hard section are made of isocyanates and alcohols chain extender.

Fiber of the present invention/polyurethane/polylactic acid blend performance meets three conditions of following (a)-(c) simultaneously:

(a) its elongation at break improves 1.5 times or more relative to pure polylactic acid；

(b) ratio >=10% that its tensile strength is improved relative to pure polylactic acid；

(c) ratio≤6% that its glass transition temperature declines relative to pure polylactic acid.

In above-mentioned condition (a), the fiber/polyurethane/polylactic acid blend elongation at break is relative to pure polylactic acid 2-14 times is usually improved, in condition (b), the fiber/polyurethane/polylactic acid blend tensile strength is relative to pure poly- The ratio that lactic acid improves is usually 12-23%.

Our experimental result show that by selecting the Material synthesis of special parameter to obtain soft segment and hard section by special ratio Example constitutes iron polyester-type thermoplastic polyurethane, it is pressed 5-20%:80-95% with polylactic acid and total amount is 100% with analogy The polyurethane/polylactic acid blend that formula is prepared can either significantly improve the elongation at break of gained modified material, and unknown It is aobvious to reduce its glass transition temperature and tensile strength；The fiber for adding specific quantity again on this basis, also can further improve The tensile strength of gained blend.

In technical solution of the present invention, test condition of the polyester-type thermoplastic polyurethane in 190 DEG C/2.16kg Under melt index be 4-25g/10min.The polylactic acid is polylactic acid conventional in the prior art, design parameter are as follows: glass Glass transition temperature is 58.9-63.1 DEG C, and the melt index under the test condition of 190 DEG C/2.16kg is 2-10g/10min.

In technical solution of the present invention, the fiber is in cotton fiber, flaxen fiber, wood-fibred and bamboo fibre Any one or two or more combinations.The fiber should be handled by conventional base extraction and silane coupling agent, Base extraction and the silane coupling agent processing being related to can preferably carry out as follows:

It takes fiber to be placed in 50-80 DEG C of lye and impregnates 2-4h, be placed in pH=3-5 after taking-up again, the silicon that temperature is 50-80 DEG C Impregnate 0.5-3h in alkane coupling agent solution, take out, it is dry to get.Wherein, lye can be existing conventional alkaline substance (such as NaOH, KOH etc.) aqueous solution, concentration 4-15wt%；The selection of silane coupling agent is same as the prior art, specifically can be with It is any one in KH550, KH560 and KH570 etc. or two or more combinations, for preparing silane coupler solution Solvent be the mixed solvent being made of water and dehydrated alcohol by the volume ratio of 1:9-4:6, silane coupling agent is in silane coupling agent Concentration in solution is usually 3-5wt%；Generally use the pH that the general inorganics acid such as hydrochloric acid, acetic acid adjusts silane coupler solution Value.

In technical solution of the present invention, the length of the fiber is preferably 2-6mm, further preferably 2-4mm.In order to Keep gained fiber/polyurethane/polylactic acid blend degradable in subsequent need, preferably fiber is that flaxen fiber or cotton are fine Dimension, wherein flaxen fiber specifically can be selected from one or both of sisal fiber, tossa, flax fiber and ramee Above combination.

In technical solution of the present invention, the polyester polyol is preferably selected from polyethylene glycol adipate (PEGA), any one in polyadipate -1,2- propylene glycol ester (PPA) and polyadipate -1,4- butanediol ester (PBA) or two Kind or more combination.The isocyanates be preferably selected from 4,4 '-diisocyanate (MDI) of diphenyl methane-, 1,6- oneself two Any one in isocyanates (HDI) and isophorone diisocyanate (IPDI) or two or more combinations.The alcohol Class chain extender is preferably ethylene glycol (EG), 1,6-HD (HD), a combination of one or more in 1,4- butanediol (BD).

The present invention also provides above-mentioned fiber/polyurethane/polylactic acid blend preparation methods, comprising the following steps:

1) each raw material is weighed by formula, prepares polyester-type thermoplastic polyurethane；

2) polyester-type thermoplastic polyurethane, polylactic acid and the fiber after drying are uniformly mixed by formula, gained mixture Through melting extrusion to get arrive the fiber/polyurethane/polylactic acid blend.

In the step 1) of above-mentioned preparation method, polyester-type thermoplastic polyurethane is prepared by existing conventional method, it specifically can be with It carries out as follows:

Under dry nitrogen protection, by vacuum dehydration (after -0.01MPa to -0.1MPa, 100-120 DEG C of dehydration 1-3h) The raw material and isocyanates as soft segment be placed in reaction kettle, after mixing, system is made to be maintained at 80-90 DEG C, heat preservation is anti- Answer 1-3h；System is cooled to≤60 DEG C later, alcohols chain extender that is dry and measuring is added under stirring condition, is uniformly mixed Afterwards, it is warming up to 70-90 DEG C of insulation reaction 3-6h, reaction resulting material is taken out, 4-6h is cured under the conditions of 100-120 DEG C, i.e., Obtain the polyester-type thermoplastic polyurethane.Wherein, the total mole number and isocyanates of polyester diol and alcohols chain extender Molal quantity it is suitable, and the additional amount of the raw material as soft segment is to control its shared quality in polyester-type thermoplastic polyurethane Than for 75-90%, total dosage of the isocyanates and alcohols chain extender is then control isocyanates and alcohols chain extender reaction The hard section of generation mass ratio shared in gained polyester-type thermoplastic polyurethane is 10-25%.

In the step 2) of above-mentioned preparation method, gained mixture is usually the melt blending in double screw extruder, then Granulation tabletting is carried out as needed, and then obtains the polyurethane/polylactic acid blend of particulate material or sheet-form.In melt blending Temperature when operation is same as the prior art, and usually 180-200 DEG C.When needing extrusion to obtain sheet material, preferably control is squeezed out Temperature is 180-200 DEG C, and temperature when cooling down slab is 35-50 DEG C.

Compared with prior art, present invention is characterized in that

1, the present invention constitutes polyester-type by specific proportions by selecting the Material synthesis of special parameter to obtain soft segment and hard section Thermoplastic polyurethane is gathered it with polylactic acid as what the proportion mode that 5-20%:80-95% and total amount are 100% was prepared Urethane/polylactic acid blend, can either significantly improve the elongation at break of gained modified material, and significantly reduce its vitrifying Transition temperature and tensile strength；The fiber for adding specific quantity again on this basis, on the basis of guaranteeing aforementioned properties further It is bright to be effectively improved existing high elongation at tear needs when prior art polydactyl acid for the tensile strength for improving gained blend The tensile strength of aobvious expendable material and the deficiency of glass transition temperature.

2, the present invention uses macromolecular plasticizer, and there is no the small molecule migrations of plasticizer and precipitation to lead to material after toughening The problem of capable of declining.

3, the raw material involved in the present invention is easy to get, and method is simple to operation.

Specific embodiment

The present invention is described in further detail combined with specific embodiments below, content to better understand the invention, but The present invention is not limited to following embodiments.

TPU, PLA involved in following embodiment, various isocyanates (MDI, HDI or IPDI) and various alcohols chain extensions Agent (EG, BD or HD) is that (resulting material water content is lower than by vacuum dehydration (- 0.1MPa, 120 DEG C of dehydration 1-3h) operation 200ppm), it is no longer described in detail in embodiment.

Embodiment 1

1) taking 8kg number-average molecular weight is that 1800 PEGA and 1.824kg isocyanates (MDI) is placed in reaction kettle, is mixed After uniformly, system is set to be maintained at 85 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, 0.176kg is added under stirring condition Alcohols chain extender (EG) is warming up to 70 DEG C of insulation reaction 5h after mixing, reaction resulting material is taken out, and in 120 DEG C 4h is cured in baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 20% in gained TPU, and soft segment is shared in TPU Mass ratio be 80%, the melt index of gained TPU is 8g/10min (under the test condition of 190 DEG C/2.16kg, similarly hereinafter)；

2) ramee for taking length to be 2-4mm, which is placed in the NaOH aqueous solution that temperature is 60 DEG C, concentration is 4wt%, to be impregnated 3h takes out, and drains and is placed on that temperature is 60 DEG C, (pH=3, solvent are by water and anhydrous second for KH550 solution that concentration is 3wt% Alcohol presses the mixed solvent of 1:9 volume ratio composition) impregnate 3h, the ramee handled well；

3) it takes fiber made from TPU, 3kg step 2) made from 2.0kg step 1) and 8.0kg melt index is 2g/10min PLA be uniformly mixed, gained mixture is placed in melt blending in double screw extruder, squeezes out (200 DEG C), through 40 DEG C of chill roll It is cooling, obtain fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 51.7MPa, elongation at break 151.05%, glass transition temperature are 59.5 DEG C.

Comparative example 1

The PLA that melt index is 2g/10min is placed in melt blending in double screw extruder, is squeezed out (200 DEG C), through 40 DEG C chill roll it is cooling, obtain polylactic acid sheet material.

Tensile strength, elongation at break and the glass transition temperature of polylactic acid sheet material obtained by this comparative example are examined It surveys, as a result are as follows: tensile strength 47.0MPa, elongation at break 10.07%, glass transition temperature are 63.1 DEG C.

Embodiment 1 is compared with comparative example 1, elongation at break of 1 resulting sheet of embodiment relative to 1 resulting sheet of comparative example 14 times are improved, tensile strength improves 10%, and glass transition temperature has dropped 5.71%.

Embodiment 2

1) taking 9kg number-average molecular weight is that 2500 PPA and 0.974kg isocyanates (MDI) is placed in reaction kettle, and mixing is equal After even, system is set to be maintained at 85 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, 0.026kg alcohol is added under stirring condition Class chain extender (BD) is warming up to 70 DEG C of insulation reaction 5h after mixing, reaction resulting material is taken out, and in 120 DEG C of baking 4h is cured in case to get TPU is arrived, hard section mass ratio shared in TPU is 10% in gained TPU, and soft segment is shared in TPU Mass ratio is 90%, and the melt index of gained TPU is 11g/10min；

2) tossa for taking length to be 2-4mm, which is placed in the NaOH aqueous solution that temperature is 60 DEG C, concentration is 15wt%, to be soaked 3h is steeped, is taken out, drains and is placed on that temperature is 80 DEG C, (pH=4, solvent are by water and anhydrous for KH550 solution that concentration is 5wt% Ethyl alcohol presses the mixed solvent of 2:8 volume ratio composition) impregnate 0.5h, the tossa handled well；

3) it takes fiber made from TPU, 2.5kg step 2) made from 2.0kg step 1) and 8.0kg melt index is 6g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (200 DEG C), through 40 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 50.71MPa, elongation at break 153.15%, glass transition temperature are 56.7 DEG C.

Comparative example 2-1

The PLA that melt index is 6g/10min is placed in melt blending in double screw extruder, is squeezed out (200 DEG C), through 40 DEG C chill roll it is cooling, obtain polylactic acid sheet material.

Tensile strength, elongation at break and the glass transition temperature of polylactic acid sheet material obtained by this comparative example are examined It surveys, as a result are as follows: tensile strength 46.1MPa, elongation at break 10.21%, glass transition temperature are 60.3 DEG C.

Embodiment 2 compared with comparative example 2-1, stretch relative to the fracture of comparative example 2-1 resulting sheet by 2 resulting sheet of embodiment Long rate improves 14 times, and tensile strength improves 10%, and glass transition temperature has dropped 5.97%.

Comparative example 2-2

It takes 2kg triphenyl phosphite and 8kg melt index to be placed in double screw extruder for the PLA of 6g/10min to melt altogether It is mixed, it squeezes out (200 DEG C), it is cooling through 40 DEG C of chill rolls, obtain triphenyl phosphite/polylactic acid sheet material.

Triphenyl phosphite/polylactic acid sheet material tensile strength, elongation at break and vitrifying obtained by this comparative example are turned Temperature is detected, as a result are as follows: tensile strength 20.1MPa, elongation at break 573.4%, glass transition temperature are 33.4℃。

Comparative example 2-2 is compared with comparative example 2-1, and comparative example 2-2 resulting sheet is relative to the disconnected of comparative example 2-1 resulting sheet It splits elongation and improves 55.16 times, tensile strength has dropped 56.40%, and glass transition temperature has dropped 44.61%.

Comparative example 2-3

It takes the poly- butylene carbonate of 2kg and 8kg melt index to be placed in double screw extruder for the PLA of 6g/10min to melt altogether It is mixed, it squeezes out (200 DEG C), it is cooling through 40 DEG C of chill rolls, obtain poly- butylene carbonate/polylactic acid sheet material.

Tensile strength, elongation at break and the vitrifying of poly- butylene carbonate/polylactic acid sheet material obtained by this comparative example are turned Temperature is detected, as a result are as follows: tensile strength 23.1MPa, elongation at break 16.89%, glass transition temperature are 42.1℃。

Comparative example 2-3 is compared with comparative example 2-1, and comparative example 2-3 resulting sheet is relative to the disconnected of comparative example 2-1 resulting sheet It splits elongation and improves 0.65 times, tensile strength has dropped 49.89%, and glass transition temperature has dropped 30.18%.

Embodiment 3

1) taking 8.5kg number-average molecular weight is that 2500 PEGA and 1.371kg isocyanates (MDI) is placed in reaction kettle, is mixed After closing uniformly, system is set to be maintained at 90 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, is added under stirring condition 0.129kg alcohols chain extender (EG) is warming up to 70 DEG C of insulation reaction 4h after mixing, and reaction resulting material is taken out, and in 4h is cured in 120 DEG C of baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 15% in gained TPU, and soft segment exists Shared mass ratio is 85% in TPU, and the melt index of gained TPU is 18g/10min；

2) sisal fiber for taking length to be 2-4mm, which is placed in the KOH aqueous solution that temperature is 60 DEG C, concentration is 12wt%, to be impregnated 3h takes out, and drains and is placed on that temperature is 60 DEG C, (pH=4, solvent are by water and anhydrous second for KH550 solution that concentration is 3wt% Alcohol presses the mixed solvent of 4:6 volume ratio composition) impregnate 3h, the sisal fiber handled well；

3) it takes fiber made from TPU, 1.5kg step 2) made from 2.0kg step 1) and 8.0kg melt index is 10g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (180 DEG C), through 35 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 53.21MPa, elongation at break 153.15%, glass transition temperature are 57.1 DEG C.

Comparative example 3

The PLA that melt index is 10g/10min is placed in melt blending in double screw extruder, is squeezed out (200 DEG C), through 40 DEG C chill roll it is cooling, obtain polylactic acid sheet material.

Tensile strength, elongation at break and the glass transition temperature of polylactic acid sheet material obtained by this comparative example are examined It surveys, as a result are as follows: tensile strength 45.7MPa, elongation at break 10.36%, glass transition temperature are 58.9 DEG C.

Embodiment 3 is compared with comparative example 3, elongation at break of 3 resulting sheet of embodiment relative to 3 resulting sheet of comparative example 14 times are improved, tensile strength improves 10%, and glass transition temperature has dropped 3.05%.

Embodiment 4

1) taking 8kg number-average molecular weight is that 1000 PEGA and 1.824kg isocyanates (HDI) is placed in reaction kettle, is mixed After uniformly, system is set to be maintained at 90 DEG C, insulation reaction 1h；System is cooled to 60 DEG C later, 0.176kg is added under stirring condition Alcohols chain extender (EG) is warming up to 70 DEG C of insulation reaction 4h after mixing, reaction resulting material is taken out, and in 120 DEG C 4h is cured in baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 20% in gained TPU, and soft segment is shared in TPU Mass ratio be 80%, the melt index of gained TPU is 6g/10min；

2) cotton fiber for taking length to be 2-4mm, which is placed in the NaOH aqueous solution that temperature is 60 DEG C, concentration is 10wt%, to be impregnated 4h takes out, and drains and is placed on that temperature is 60 DEG C, (pH=5, solvent are by water and anhydrous second for KH570 solution that concentration is 3wt% Alcohol presses the mixed solvent of 3:7 volume ratio composition) impregnate 3h, the cotton fiber handled well；

3) it takes fiber made from TPU, 1.5kg step 2) made from 2.0kg step 1) and 8.0kg melt index is 6g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (200 DEG C), through 40 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 51.86MPa, elongation at break 152.49%, glass transition temperature are 57.6 DEG C.

Embodiment 5

1) taking 7.5kg number-average molecular weight is that 1000 PPA and 2.260kg isocyanates (IPDI) is placed in reaction kettle, is mixed After closing uniformly, system is set to be maintained at 90 DEG C, insulation reaction 1h；System is cooled to 60 DEG C later, is added under stirring condition 0.240kg alcohols chain extender (BD) is warming up to 70 DEG C of insulation reaction 6h after mixing, and reaction resulting material is taken out, and in 4h is cured in 120 DEG C of baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 25% in gained TPU, and soft segment exists Shared mass ratio is 75% in TPU, and the melt index of gained TPU is 4g/10min；

2) bamboo fibre for taking length to be 2-6mm, which is placed in the KOH aqueous solution that temperature is 60 DEG C, concentration is 6wt%, impregnates 4h, It takes out, drains and be placed on that temperature is 80 DEG C, (pH=3, solvent are to be pressed by water and dehydrated alcohol for KH590 solution that concentration is 3wt% The mixed solvent of 2:8 volume ratio composition) impregnate 3h, the carbon fiber handled well；

3) it takes fiber made from TPU, 2.5kg step 2) made from 1.5kg step 1) and 8.5kg melt index is 2g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (210 DEG C), through 50 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 52.64MPa, elongation at break 140.98%, glass transition temperature are 62.1 DEG C.

Embodiment 6

1) taking 8.5kg number-average molecular weight is that 2500 PEGA and 1.242kg isocyanates (IPDI) is placed in reaction kettle, is mixed After closing uniformly, system is set to be maintained at 90 DEG C, insulation reaction 1h；System is cooled to 60 DEG C later, is added under stirring condition 0.258kg alcohols chain extender (HD) is warming up to 70 DEG C of insulation reaction 3h after mixing, and reaction resulting material is taken out, and in 4h is cured in 120 DEG C of baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 15% in gained TPU, and soft segment exists Shared mass ratio is 85% in TPU, and the melt index of gained TPU is 25g/10min；

2) wood-fibred for taking length to be 2-4mm, which is placed in the KOH aqueous solution that temperature is 70 DEG C, concentration is 8wt%, impregnates 3h, It takes out, drains and be placed on that temperature is 60 DEG C, (pH=3, solvent are to be pressed by water and dehydrated alcohol for KH570 solution that concentration is 3wt% The mixed solvent of 1:9 volume ratio composition) impregnate 2h, the nylon fiber handled well；

3) it takes fiber made from TPU, 2kg step 2) made from 1.5kg step 1) and 8.5kg melt index is 10g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (180 DEG C), through 35 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 51.86MPa, elongation at break 144.36.1%, glass transition temperature are 55.4 DEG C.

Embodiment 7

1) taking 8kg number-average molecular weight is that 1500 PBA and 1.703kg isocyanates (HDI) is placed in reaction kettle, and mixing is equal After even, system is set to be maintained at 80 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, 0.297kg alcohol is added under stirring condition Class chain extender (EG) is warming up to 70 DEG C of insulation reaction 6h after mixing, reaction resulting material is taken out, and in 120 DEG C of baking 4h is cured in case to get TPU is arrived；Hard section mass ratio shared in TPU is 20% in gained TPU, and soft segment is shared in TPU Mass ratio is 80%, and the melt index of gained TPU is 15g/10min；

2) flax fiber for taking length to be 2-6mm, which is placed in the KOH aqueous solution that temperature is 60 DEG C, concentration is 6wt%, to be impregnated 2h takes out, and drains and is placed on that temperature is 70 DEG C, (pH=3, solvent are by water and anhydrous second for KH550 solution that concentration is 3wt% Alcohol presses the mixed solvent of 2:8 volume ratio composition) impregnate 1.5h, the polyester fiber handled well；

3) it takes fiber made from TPU, 2.8kg step 2) made from 1.5kg step 1) and 8.5kg melt index is 6g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (185 DEG C), through 42 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 52.57MPa, elongation at break 140.76%, glass transition temperature are 59.8 DEG C.

Embodiment 8

1) taking 8.5kg number-average molecular weight is that 2000 PEGA and 1.413kg isocyanates (MDI) is placed in reaction kettle, is mixed After closing uniformly, system is set to be maintained at 80 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, is added under stirring condition 0.087kg alcohols chain extender (EG) is warming up to 70 DEG C of insulation reaction 6h after mixing, and reaction resulting material is taken out, and in 4h is cured in 120 DEG C of baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 15% in gained TPU, and soft segment exists Shared mass ratio is 85% in TPU, and the melt index of gained TPU is 2g/10min；

2) sisal fiber for taking length to be 2-4mm, which is placed in the NaOH aqueous solution that temperature is 60 DEG C, concentration is 10wt%, to be soaked 2h is steeped, is taken out, drains and is placed on that temperature is 75 DEG C, (pH=3, solvent are by water and anhydrous for KH560 solution that concentration is 3wt% Ethyl alcohol presses the mixed solvent of 3:7 volume ratio composition) impregnate 3h, the sisal fiber handled well；

3) it takes fiber made from TPU, 2kg step 2) made from 1.5kg step 1) and 8.5kg melt index is 2g/10min PLA be uniformly mixed, gained mixture is placed in melt blending in double screw extruder, squeezes out (185 DEG C), through 45 DEG C of chill roll It is cooling, obtain fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 53.73MPa, elongation at break 127.60%, glass transition temperature are 62.3 DEG C.

Embodiment 9

1) taking 8kg number-average molecular weight is that 2200 PBA and 1.656kg isocyanates (IPDI) is placed in reaction kettle, is mixed After uniformly, system is set to be maintained at 80 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, 0.344kg is added under stirring condition Alcohols chain extender (BD) is warming up to 90 DEG C of insulation reaction 3h after mixing, reaction resulting material is taken out, and in 120 DEG C 4h is cured in baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 20% in gained TPU, and soft segment is shared in TPU Mass ratio be 80%, the melt index of gained TPU is 13g/10min；

2) taking sisal fiber that length is 2-4mm and cotton fiber (weight ratio 2:1) to be placed in, temperature is 60 DEG C, concentration is 2h is impregnated in the NaOH aqueous solution of 10wt%, takes out, drains the KH570 solution for being placed on that temperature is 60 DEG C, concentration is 3wt% (pH=3, solvent are the mixed solvent being made of water and dehydrated alcohol by 1:9 volume ratio) impregnates 3h, the sisal hemp handled well Fiber；

3) it takes fiber made from TPU, 3kg step 2) made from 1.0kg step 1) and 9.0kg melt index is 6g/10min PLA be uniformly mixed, gained mixture is placed in melt blending in double screw extruder, squeezes out (185 DEG C), through 40 DEG C of chill roll It is cooling, obtain fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 54.32MPa, elongation at break 63.12%, glass transition temperature are 58.1 DEG C.

Embodiment 10

1) taking 7.5kg number-average molecular weight is that 1000 PEGA and 2.335kg isocyanates (MDI) is placed in reaction kettle, is mixed After closing uniformly, system is set to be maintained at 80 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, is added under stirring condition 0.165kg alcohols chain extender (BD) is warming up to 70 DEG C of insulation reaction 6h after mixing, and reaction resulting material is taken out, and in 4h is cured in 120 DEG C of baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 25% in gained TPU, and soft segment exists Shared mass ratio is 75% in TPU, and the melt index of gained TPU is 17g/10min；

2) taking ramee that length is 2-4mm and flax fiber (weight ratio 1:1) to be placed in, temperature is 60 DEG C, concentration is 4h is impregnated in the NaOH aqueous solution of 6wt%, takes out, drains the KH550 solution (pH for being placed on that temperature is 70 DEG C, concentration is 3wt% =4, solvent is the mixed solvent being made of water and dehydrated alcohol by 1:9 volume ratio) impregnate 2h, the fiber handled well；

3) it takes fiber made from TPU, 2.8kg step 2) made from 1.0kg step 1) and 9.0kg melt index is 2g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (190 DEG C), through 45 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 52.56MPa, elongation at break 72.34%, glass transition temperature are 59.8 DEG C.

Embodiment 11

1) taking 8kg number-average molecular weight is that 1300 PPA and 1.818kg isocyanates (IPDI) is placed in reaction kettle, is mixed After uniformly, system is set to be maintained at 80 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, 0.182kg is added under stirring condition Alcohols chain extender (BD) is warming up to 70 DEG C of insulation reaction 6h after mixing, reaction resulting material is taken out, and in 120 DEG C 4h is cured in baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 20% in gained TPU, and soft segment is shared in TPU Mass ratio be 80%, the melt index of gained TPU is 10g/10min；

2) sisal fiber for taking length to be 2-4mm, which is placed in the NaOH aqueous solution that temperature is 60 DEG C, concentration is 10wt%, to be soaked 4h is steeped, is taken out, drains and is placed on that temperature is 70 DEG C, (pH=4, solvent are by water and anhydrous for KH550 solution that concentration is 3wt% Ethyl alcohol presses the mixed solvent of 2:8 volume ratio composition) impregnate 2.5h, the sisal fiber handled well；

3) it takes fiber made from TPU, 2kg step 2) made from 1.0kg step 1) and 9.0kg melt index is 10g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (190 DEG C), through 45 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 53.12MPa, elongation at break 63.78%, glass transition temperature are 55.9 DEG C.

Embodiment 12

1) taking 8kg number-average molecular weight is that 1500 PEGA and 1.868kg isocyanates (MDI) is placed in reaction kettle, is mixed After uniformly, system is set to be maintained at 85 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, 0.132kg is added under stirring condition Alcohols chain extender (EG) is warming up to 70 DEG C of insulation reaction 6h after mixing, reaction resulting material is taken out, and in 120 DEG C 4h is cured in baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 20% in gained TPU, and soft segment is shared in TPU Mass ratio be 80%, the melt index of gained TPU is 12g/10min；

2) ramee for taking length to be 2-4mm, which is placed in the NaOH aqueous solution that temperature is 60 DEG C, concentration is 12wt%, to be soaked Steep 3h, take out, drain be placed on temperature is 60 DEG C, concentration is 5wt% KH570 and KH550 (by 1:1) solution (pH=3, it is molten Agent is the mixed solvent being made of water and dehydrated alcohol by 4:6 volume ratio) impregnate 1h, the ramee handled well；

3) it takes fiber made from TPU, 1.5kg step 2) made from 1.0kg step 1) and 9.0kg melt index is 2g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (200 DEG C), through 50 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 55.12MPa, elongation at break 76.45%, glass transition temperature are 59.7 DEG C.

Embodiment 13

1) taking 8.5kg number-average molecular weight is that 1500 PBA and 1.309kg isocyanates (HDI) is placed in reaction kettle, is mixed After uniformly, system is set to be maintained at 90 DEG C, insulation reaction 3h；System is cooled to 55 DEG C later, 0.191kg is added under stirring condition Alcohols chain extender (BD) is warming up to 70 DEG C of insulation reaction 5h, glue is taken out, and is ripe in 120 DEG C of baking oven after mixing Change 4h to get TPU is arrived；Hard section mass ratio shared in TPU is 15% in gained TPU, soft segment mass ratio shared in TPU It is 85%, the melt index of gained TPU is 10g/10min；

2) tossa for taking length to be 2-4mm, which is placed in the NaOH aqueous solution that temperature is 60 DEG C, concentration is 8wt%, to be impregnated 2h takes out, and drains and is placed on that temperature is 70 DEG C, (pH=3, solvent are by water and anhydrous second for KH550 solution that concentration is 3wt% Alcohol presses the mixed solvent of 1:9 volume ratio composition) impregnate 1.5h, the tossa handled well；

3) it takes fiber made from TPU, 2kg step 2) made from 0.5kg step 1) and 9.5kg melt index is 2g/10min PLA be uniformly mixed, gained mixture is placed in melt blending in double screw extruder, squeezes out (195 DEG C), through 40 DEG C of chill roll It is cooling, obtain fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 57.81MPa, elongation at break 25.18%, glass transition temperature are 62.7 DEG C.

Embodiment 13 is compared with comparative example 1, extension at break of 13 resulting sheet of embodiment relative to 1 resulting sheet of comparative example Rate improves 1.5 times, and tensile strength improves 23%, and glass transition temperature has dropped 0.63%.

Embodiment 14

1) taking 8.5kg number-average molecular weight is that 1800 PEGA and 1.370kg isocyanates (IPDI) is placed in reaction kettle, is mixed After closing uniformly, system is set to be maintained at 80 DEG C, insulation reaction 3h；System is cooled to 50 DEG C later, is added under stirring condition 0.130kg alcohols chain extender (BD) is warming up to 80 DEG C of insulation reaction 4h after mixing, and reaction resulting material is taken out, and in 4h is cured in 120 DEG C of baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 15% in gained TPU, and soft segment exists Shared mass ratio is 85% in TPU, and the melt index of gained TPU is 12g/10min；

2) sisal fiber for taking length to be 2-4mm, which is placed in the KOH aqueous solution that temperature is 60 DEG C, concentration is 6wt%, to be impregnated 2h takes out, and drains and is placed on that temperature is 80 DEG C, (pH=3, solvent are by water and anhydrous second for KH560 solution that concentration is 3wt% Alcohol presses the mixed solvent of 3:7 volume ratio composition) impregnate 3h, the sisal fiber handled well；

3) it takes fiber made from TPU, 2kg step 2) made from 0.5kg step 1) and 9.5kg melt index is 6g/10min PLA be uniformly mixed, gained mixture is placed in melt blending in double screw extruder, squeezes out (185 DEG C), through 45 DEG C of chill roll It is cooling, obtain fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 56.71MPa, elongation at break 25.53%, glass transition temperature are 57.6 DEG C.

Embodiment 14 is compared with comparative example 2-1, fracture of 14 resulting sheet of embodiment relative to comparative example 2-1 resulting sheet Elongation improves 1.5 times, and tensile strength improves 23%, and glass transition temperature has dropped 4.48%.

Embodiment 15

1) taking 8kg number-average molecular weight is that 2100 PEGA and 1.723kg isocyanates (MDI) is placed in reaction, and mixing is equal After even, system is set to be maintained at 80 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, 0.277kg alcohol is added under stirring condition Class chain extender (BD) is warming up to 70 DEG C of insulation reaction 6h after mixing, reaction resulting material is taken out, and in 120 DEG C of baking 4h is cured in case to get TPU is arrived；Hard section mass ratio shared in TPU is 20% in gained TPU, and soft segment is shared in TPU Mass ratio is 80%, and the melt index of gained TPU is 14g/10min；

2) ramee for taking length to be 2-4mm, which is placed in the KOH aqueous solution that temperature is 60 DEG C, concentration is 10wt%, to be impregnated 3h takes out, and drains and is placed on that temperature is 60 DEG C, (pH=3, solvent are by water and anhydrous second for KH570 solution that concentration is 3wt% Alcohol presses the mixed solvent of 1:9 volume ratio composition) impregnate 3h, the ramee handled well；

3) it takes fiber made from TPU, 1kg step 2) made from 0.5kg step 1) and 9.5kg melt index is 10g/ The PLA of 10min is uniformly mixed, and gained mixture is placed in melt blending in double screw extruder, is squeezed out (200 DEG C), through 40 DEG C Chill roll is cooling, obtains fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 56.22MPa, elongation at break 25.91%, glass transition temperature are 58.3 DEG C.

Embodiment 15 is compared with comparative example 3, extension at break of 15 resulting sheet of embodiment relative to 3 resulting sheet of comparative example Rate improves 1.5 times, and tensile strength improves 23%, and glass transition temperature has dropped 1.02%.

Embodiment 16

1) taking 7.5kg number-average molecular weight is that 1800 PEGA and 1.628kg isocyanates (HDI) is placed in reaction kettle, is mixed After closing uniformly, system is set to be maintained at 80 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, is added under stirring condition 0.497kg alcohols chain extender (BD) is warming up to 90 DEG C of insulation reaction 3h after mixing, and reaction resulting material is taken out, and in 4h is cured in 120 DEG C of baking oven to get TPU is arrived；Hard section mass ratio shared in TPU is 25% in gained TPU, and soft segment exists Shared mass ratio is 75% in TPU, and the melt index of gained TPU is 14g/10min；

2) it takes the sword ramie fiber that length is 2-4mm to be placed in the NaOH aqueous solution that temperature is 60 DEG C, concentration is 12wt% to soak 2h is steeped, is taken out, drains and is placed on that temperature is 70 DEG C, (pH=3, solvent are by water and anhydrous for KH550 solution that concentration is 3wt% Ethyl alcohol presses the mixed solvent of 2:8 volume ratio composition) impregnate 2h, the ramee handled well；

3) it takes fiber made from TPU, 1kg step 2) made from 0.5kg step 1) and 9.5kg melt index is 6g/10min PLA be uniformly mixed, gained mixture is placed in melt blending in double screw extruder, squeezes out (190 DEG C), through 45 DEG C of chill roll It is cooling, obtain fiber/polyurethane/polylactic acid sheet material.

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 55.82MPa, elongation at break 28.79%, glass transition temperature are 60.1 DEG C.

Embodiment 17

Embodiment 16 is repeated, unlike:

Step 1) pushing operation carries out:

Taking 7.5kg number-average molecular weight is the isocyanic acid of 1800 PEGA and 0.830kg isocyanates (HDI) and 1.236kg Ester (MDI) is placed in reaction kettle, after mixing, so that system is maintained at 80 DEG C, insulation reaction 2h；System is cooled to 60 later DEG C, 0.035kg alcohols chain extender (BD) is added under stirring condition and 0.024kg chain extender (EG) is warming up to 90 after mixing DEG C insulation reaction 3h takes out reaction resulting material, and cures 4h in 120 DEG C of baking oven to get TPU is arrived；It is hard in gained TPU Section mass ratio shared in TPU is 25%, and soft segment mass ratio shared in TPU is 75%, and the melt index of gained TPU is 15g/10min；

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 53.21MPa, elongation at break 27.56%, glass transition temperature are 60.2 DEG C.

Embodiment 18

Embodiment 16 is repeated, unlike:

Step 1) pushing operation carries out:

Taking 7.5kg number-average molecular weight is the isocyanic acid of 1800 PEGA and 0.312kg isocyanates (HDI) and 0.696kg The isocyanates (IPDI) of ester (MDI) and 1.031kg are placed in reaction kettle, after mixing, so that system is maintained at 80 DEG C, heat preservation React 2h；System is cooled to 60 DEG C later, 0.460kg alcohols chain extender (BD) is added under stirring condition, after mixing, is risen Temperature takes out reaction resulting material to 90 DEG C of insulation reaction 3h, and cures 4h in 120 DEG C of baking oven to get TPU is arrived；Gained Hard section mass ratio shared in TPU is 25% in TPU, and soft segment mass ratio shared in TPU is 75%, and gained TPU's is molten Melting index is 16g/10min；

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 55.46MPa, elongation at break 28.69%, glass transition temperature are 60.0 DEG C.

Embodiment 19

Embodiment 8 is repeated, unlike:

Step 1) pushing operation carries out:

Take PBA, 4.279kg that PEGA, 3.081kg number-average molecular weight that 1.141kg number-average molecular weight is 1000 are 1800 PPA, 1.480kg isocyanates (MDI) that number-average molecular weight is 1500 are placed in reaction kettle, after mixing, keep system At 80 DEG C, insulation reaction 2h；System is cooled to 60 DEG C later, under stirring condition be added 0.003kg alcohols chain extender (EG), It is anti-to be warming up to 90 DEG C of heat preservations after mixing for the alcohols chain extender (BD) of 0.006kg and the alcohols chain extender (HD) of 0.012kg 3h is answered, reaction resulting material is taken out, and cures 4h in 120 DEG C of baking oven to get TPU is arrived；Hard section is in TPU in gained TPU In shared mass ratio be 25%, soft segment mass ratio shared in TPU is 75%, and the melt index of gained TPU is 17g/ 10min；

The tensile strength of the present embodiment resulting sheet, elongation at break and glass transition temperature are detected, as a result Are as follows: tensile strength 54.55MPa, elongation at break 129.36%, glass transition temperature are 62.4 DEG C.

Claims (10)

1. a kind of fiber/polyurethane/polylactic acid blend, it is characterised in that: the blend is by polyester-type thermoplastic polyurethane, poly- Lactic acid and fiber are constituted, and the dosage of the fiber is the 10-30% of polyester-type thermoplastic polyurethane and polylactic acid quality sum；Its In, it is in terms of 100%, shared by the polyester-type thermoplastic polyurethane by the quality sum of polyester-type thermoplastic polyurethane and polylactic acid Mass ratio be 5-20%, surplus is polylactic acid；Wherein:

The polyester-type thermoplastic polyurethane is the polyester-type thermoplastic polyurethane of undefined structure, the polyester-type thermoplastic poly Urethane is made of soft segment and hard section, and in the composition of polyester-type thermoplastic polyurethane, by mass percentage, soft segment accounts for polyester-type The 75-90% of thermoplastic polyurethane quality, surplus are hard section；Wherein, soft segment is that the polyester that number-average molecular weight is 1000-2500 is more First alcohol, hard section are made of isocyanates and alcohols chain extender.

2. fiber according to claim 1/polyurethane/polylactic acid blend, it is characterised in that: the performance of the blend is same When meet three conditions of following (a)-(c):

(a) its elongation at break improves 1.5 times or more relative to pure polylactic acid；

(b) ratio >=10% that its tensile strength is improved relative to pure polylactic acid；

(c) ratio≤6% that its glass transition temperature declines relative to pure polylactic acid.

3. fiber according to claim 2/polyurethane/polylactic acid blend, it is characterised in that: described in condition (a) The elongation at break of blend improves 2-14 times relative to pure polylactic acid；In condition (b), the tensile strength phase of the blend It is 12-23% for the ratio that pure polylactic acid improves.

4. fiber according to any one of claim 1-3/polyurethane/polylactic acid blend, it is characterised in that: described Melt index of the polyester-type thermoplastic polyurethane under the test condition of 190 DEG C/2.16kg is 4-25g/10min.

5. fiber according to any one of claim 1-3/polyurethane/polylactic acid blend, it is characterised in that: described Fiber is the combination selected from one or more of cotton fiber, flaxen fiber, carbon fiber, wood-fibred and bamboo fibre.

6. fiber according to any one of claim 1-3/polyurethane/polylactic acid blend, it is characterised in that: the fibre The length of dimension is 2-6mm.

7. fiber according to any one of claim 1-3/polyurethane/polylactic acid blend, it is characterised in that: described Polyester polyol be selected from one of polyethylene glycol adipate, polypropylene glycol adipate and poly adipate succinic acid ester or Two or more combinations.

8. fiber according to any one of claim 1-3/polyurethane/polylactic acid blend, it is characterised in that: described Isocyanates is selected from 4,4 '-diisocyanate of diphenyl methane-, 1, hexamethylene-diisocyanate and isophorone diisocyanate One or more of combination.

9. fiber according to any one of claim 1-3/polyurethane/polylactic acid blend, it is characterised in that: described Alcohols chain extender is any one in ethylene glycol, 1,6-HD and 1,4- butanediol or two or more combinations.

10. fiber described in claim 1/polyurethane/polylactic acid blend preparation method, comprising the following steps:

1) each raw material is weighed by formula, prepares polyester-type thermoplastic polyurethane；

2) polyester-type thermoplastic polyurethane, polylactic acid and the fiber after drying are uniformly mixed by formula, gained mixture is through molten Melt extrusion to get the fiber/polyurethane/polylactic acid blend is arrived.