Embodiment
The manufacture method of poly(lactic acid) of the present invention, it is to make plants starch and lactobacillus-fermented and generate lactic acid, make described acid by dehydrating lactic polycondensation again and the poly(lactic acid) manufacture method of synthesizing polylactic acid, it is characterized in that, comprise following operation: the fermentation enrichment process, has at least one pair of electrode, in the fermentor tank of the cathode side that next door and the concentrated portion that is separated by described next door and described concentrated portion are located at described electrode, to containing described plants starch, feed direct current in the mixture of described milk-acid bacteria and described lactic acid, make described lactic acid be transferred to described concentrated portion and store in described concentrated portion by osmosis; Polymerization process has in supply to store in the polymerization tank of the described lactic acid of described concentrated portion, heats described lactic acid, makes its dehydration polycondensation and synthesizing polylactic acid.
According to the manufacture method of poly(lactic acid) of the present invention (below, be sometimes referred to as " manufacture method of the present invention "), be used for the lactic acid manufacturing processed of production poly(lactic acid), utilizing electro-osmotic effects the lactic acid in the fermentor tank can be separated from unfermentable milk-acid bacteria and plants starch.Thereby it is low to keep in the mixture directly related with the generation of lactic acid concentration of lactic acid in fermentor tank, and the pH that can suppress said mixture reduces.Thus, manufacturing method according to the invention can obtain the lactic acid of high density, by using this lactic acid, can efficient make the poly(lactic acid) with desired molecular weight well.So-called above-mentioned " osmosis " is meant that the neutral solvent that is caused by potential difference is with electrical way moving by porous materials such as films.
In addition, manufacturing method according to the invention, can also comprise the electro-dewatering operation, described electro-dewatering operation is to be located in the electro-dewatering jar of cathode side of described electrode having at least one pair of electrode, next door and the dehydration portion that is separated by described next door and described dehydration portion, the lactic acid polymer that obtains of dehydration polycondensation feeds direct current in described polymerization process, makes water in the described lactic acid polymer be transferred to described dehydration portion by osmosis.
Manufacturing method according to the invention in the electro-dewatering operation, can make the water that contains in the lactic acid polymer (poly(lactic acid)) that the dehydration polycondensation forms in the polymerization process be transferred to dehydration portion by osmosis.Thus, even in the polymerization of carrying out lactic acid polymer and the state that viscosity uprises also can efficient dewater well.In addition, in this manual, so-called " lactic acid polymer " is meant the poly(lactic acid) in the stage reach the poly(lactic acid) with desired molecular weight in manufacture method of the present invention and each device before, be the oligopolymer of lactic acid and the poly(lactic acid) that does not also reach desired molecular weight, described lactic acid polymer comprises that lactic acid polymer contains the state of the moisture that produces in the dehydration polycondensation of lactic acid.
In manufacture method of the present invention, can preferably use W-Gum as plants starch.
Lactic acid manufacturing installation of the present invention is characterised in that, have fermentor tank and raw material gatherer, the concentrated portion that described fermentor tank has at least one pair of electrode, next door and separated by described next door, and described concentrated portion is located at the cathode side of described electrode, and described raw material gatherer imports described fermentor tank with plants starch and milk-acid bacteria; In the mixture of lactic acid, described plants starch and described milk-acid bacteria, feed direct current, make described lactic acid be transferred to described concentrated portion by osmosis, described lactic acid in described fermentor tank with described plants starch and described lactobacillus-fermented and obtain.
In the lactic acid manufacturing installation of the present invention, feed direct current, utilize electro-osmotic effects, the lactic acid in the fermentor tank can be separated from unfermentable milk-acid bacteria and plants starch by the mixture in fermentor tank.Thereby it is low to keep in the mixture directly related with the generation of lactic acid concentration of lactic acid in fermentor tank, and the pH that can suppress said mixture reduces.Thus, the lactic acid of can efficient making high density according to lactic acid manufacturing installation of the present invention well.In addition, in the lactic acid manufacturing installation of the present invention, the anode of described electrode can form netted.
Lactic acid manufacturing installation of the present invention can also have as lower unit: vent pipe is used for the lactic acid that is transferred to described concentrated portion is discharged; Lactic acid stores jar, is supplied with so far by the described lactic acid that described vent pipe is discharged, and this stores jar and is used to store described lactic acid; Supply-pipe is used for that described lactic acid is stored jar interior lactic acid and is supplied to described concentrated portion; Discharger is used for that described lactic acid is stored jar interior described lactic acid and is discharged to the outside.
In lactic acid manufacturing installation of the present invention, the concentrated portion of fermentor tank and lactic acid store jar and form circulation by vent pipe and supply-pipe, can further improve concentration of lactic acid.
Poly(lactic acid) manufacturing installation of the present invention is characterised in that to have as lower unit: the lactic acid gatherer is used to import lactic acid; Poly-unit, heating make its dehydration polycondensation by the lactic acid that described lactic acid gatherer imports; And apparatus for electrodewatering, the dehydration portion that it has at least one pair of electrode, next door and is separated by described next door, and described dehydration portion is located at the cathode side of described electrode; In described apparatus for electrodewatering, in the lactic acid polymer that obtains by described poly-unit dehydration polycondensation, feed direct current, make water in the described lactic acid polymer be transferred to described dehydration portion by osmosis and dewater.
According to poly(lactic acid) manufacturing installation of the present invention, can make the water that contains in the lactic acid (poly(lactic acid)) that the dehydration polycondensation forms in the polymerization tank move to dehydration portion by osmosis.Thus, even in the polymerization of carrying out poly(lactic acid) and the state that viscosity uprises also can efficient dewater well, and can high-level efficiency and make with the short period of time and to have the poly(lactic acid) of desired molecular weight.
In addition, poly(lactic acid) manufacturing installation of the present invention also has raw material gatherer and the fermentor tank that is used to import plants starch and milk-acid bacteria, in described fermentor tank, be equipped with the fermentation concentrating unit, at least one pair of electrode, next door be housed in the described fermentation concentrating unit and separate and be located at the concentrated portion of the cathode side of described electrode by described next door; In described fermentation concentrating unit, in the lactic acid that obtains to the described plants starch that in described fermentor tank, imports and lactobacillus-fermented by described raw material gatherer, feed direct current, make described lactic acid be transferred to described concentrated portion by osmosis, and store in described concentrated portion, the lactic acid that will store again in described concentrated portion is supplied to described poly-unit.
Poly(lactic acid) manufacturing installation of the present invention is owing to also having the fermentation concentrating unit, so can supply with the lactic acid of high density to polymerization tank.And, lactic acid be can carry out continuously and operation and poly lactic acid polymerized operation generated, can efficient make poly(lactic acid) well.
In poly(lactic acid) manufacturing installation of the present invention, described fermentation concentrating unit has as lower unit: vent pipe is used to discharge the described lactic acid that stores in described concentrated portion; Lactic acid stores jar, is supplied with so far by the described lactic acid that described vent pipe is discharged, and this stores jar and is used to store described lactic acid; Supply-pipe is used for that described lactic acid is stored jar interior lactic acid and is supplied to described concentrated portion; And feedway, be used for that described lactic acid is stored jar interior described lactic acid and be supplied to described poly-unit.
In poly(lactic acid) manufacturing installation of the present invention, make the concentrated portion of fermentor tank and lactic acid store a jar formation circulation by vent pipe and supply-pipe, can further improve concentration of lactic acid.And in the poly(lactic acid) manufacturing installation of the present invention, the anode of described electrode can be made of netted.
In the poly(lactic acid) manufacturing installation of the present invention, described poly-unit has as lower unit: hollow matrix, its two ends have peristome and supply with described lactic acid from the peristome of an end to it; Bar-shaped rotator, it is built in described hollow matrix and has spiral groove, and the width of described groove narrows down to the peristome of the above-mentioned the other end from the peristome of an above-mentioned end; With the heating unit that is used to heat described hollow matrix inside; Can rotate by making described bar-shaped rotator, and heat the described lactic acid of force feed to the peristome of the described the other end, make described lactic acid compression from the peristome of a described end.Above-mentioned bar-shaped rotator also can have spiral groove, and the width of groove narrows down to the peristome of the above-mentioned the other end from the peristome of an above-mentioned end.
According to poly(lactic acid) manufacturing installation of the present invention, when bar-shaped rotator rotates, lactic acid is in the heated while, by along its spiral groove from the lactic acid supply side that is located at hollow matrix one end to the extrusion oral-lateral force feed of the other end, and can compress based on desired pressure.Thus, can efficient heat the lactic acid and the polycondensation of dewatering well.
For the internal structure of hollow matrix, the cross section can constitute by arbitrary shapes such as circle, ellipse, rectangle, squares, and still, the pressure that gives lactic acid based on the bar-shaped rotator of matrix inside rotation is that uniform angle is considered, is preferably formed rounded section.When spiral groove was built in the hollow matrix, the mode that can narrow down gradually to outlet side from the lactic acid supply side with screw pitch (furrow width) was provided with to the other end by an end of bar-shaped rotator, and the force feed plant material.Therefore, from can efficient well evenly the angle of compression consider that bar-shaped rotator is preferably made the rhoptry that the cross section is a circular.
In the poly(lactic acid) manufacturing installation of the present invention, described apparatus for electrodewatering has ducted body and a plurality of agitating vane, described ducted body is inserted logical described lactic acid, described a plurality of agitating vane is arranged on the inside of described ducted body and is the turning axle rotation with the direction of inserting logical described lactic acid, and the mutual opposite spin of the blade of disposed adjacent.
Poly(lactic acid) manufacturing installation of the present invention preferably is subjected to by the hydrodynamicpressure that fluid produced of inserting logical ducted body inside, promptly be subjected to the hydrodynamicpressure that flows and produced of the lactic acid polymer that polymerization obtains in polymerization tank (poly(lactic acid)), and the structure that makes agitating vane rotation (for example, have the foliated stator of spiral etc. for the power that is subjected to flow direction rotates), thus can not connect driving part and continuously stirring.Described a plurality of agitating vane is inserted logical direction with fluidic and is rotated as turning axle, and the mutual opposite spin of the blade of disposed adjacent (that is, alternately opposite spin), thereby by stirring lactic acid polymer, can easily separate water outlet by osmosis.Consequently, can make the dewatering unit miniaturization, and not be attended by the reduction of dewatering efficiency.In the formation of agitating vane, also can be rotated by motor or the magnetic force that is connected with power supply.The internal structure of ducted body constitutes in the mode that can insert logical lactic acid polymer etc., and the cross section can form arbitrary shapes such as circle, ellipse, rectangle, square, and special preferred cross-sections be the ducted body of circle.
In addition, preferably on above-mentioned agitating vane, connect power supply, its anode as electrode in the above-mentioned apparatus for electrodewatering is played a role.Thus, along with the stirring of agitating vane, be mixed in the easily close anode of the water capacity in the lactic acid polymer, thereby can dewater more expeditiously.
Plant amylum as using in lactic acid manufacturing installation of the present invention and the poly(lactic acid) manufacturing installation preferably uses W-Gum.Plants starch among the present invention can use any plants starch, but considers from the quality equal angles of the difficulty or ease of operating efficiency, acquisition, the poly(lactic acid) that obtains, preferably uses W-Gum.
Below, with reference to the description of drawings embodiments of the present invention.In addition, following in main explanation use the situation of W-Gum as plants starch, but the present invention is not limited to these embodiments.
[manufacture method of poly(lactic acid)]
The manufacture method of poly(lactic acid) of the present invention roughly is divided into W-Gum and lactobacillus-fermented and generates lactic acid and carry out the polymeric polymerization process with its spissated fermentation enrichment process with the lactic acid that obtains.Below, in each operation, use the situation of lactic acid manufacturing installation of the present invention and poly(lactic acid) manufacturing installation with example explanation.
<fermentation enrichment process 〉
Describe with Fig. 1~3 pair lactic acid manufacturing installation of the present invention.Fig. 1 is a sketch of schematically representing the structure of lactic acid manufacturing installation of the present invention.As shown in Figure 1, have mixing device 20, fermentor tank 30 and lactic acid in the formation of lactic acid manufacturing installation 10 of the present invention and store jar 50.In the lactic acid manufacturing installation 10, the mixture that blended contains W-Gum and milk-acid bacteria in mixing device 20 ferments in fermentor tank 30 and generates lactic acid, again with the lactic acid of generation and other mixture separation, concentrate by circulating store jars 50 at fermentor tank 30 and lactic acid between, and obtain the lactic acid of high density.
Mixing device 20 is not particularly limited, and is the device with known mixing devices such as stirrers.In described mixing device 20, also supplying with except that W-Gum and milk-acid bacteria has water and other additives such as enzyme etc.At this moment, the ratio of mixture of W-Gum in the mixture (x) and milk-acid bacteria (y) (mass ratio x: y) be preferably 1000: 0.1 to 1000: 10, more preferably 1000: 0.5 to 1000: 5.In addition, can be after in advance W-Gum being applied saccharification processing etc., mix with milk-acid bacteria again and constitute mixture.As above-mentioned additive, can enumerate salt, lime carbonate, various enzymes etc.At this moment, be preferably the 0.5 quality %~1 quality % of mixture as the content of above-mentioned lime carbonate.The W-Gum that mixing device 20 will be supplied with etc. mixes, and makes mixture, and this mixture is imported in fermentor tank 30.
In fermentor tank 30, be built-in with at least one pair of electrode that forms by anode 32 and negative electrode 34, these electrodes are connected and omit on the illustrated power supply.In addition, separating between anode 32 and negative electrode 34 with next door 36 in the jar of fermentor tank 30, is boundary with next door 36, is provided with in the side with negative electrode 34 and concentrates portion 38, and be provided with fermentation portion 40 in the side with anode 32.The mixture of being supplied with by mixing device 20 is imported into fermentation portion 40.In addition, the material as constituting fermentor tank 30 is not particularly limited, but considers preferred titanium (Ti) from the angle of rust-preventing characteristic.
Anode 32 and negative electrode 34 preferably are made of platinum precious metals such as (Pt), preferably use the material after titanium (Ti) is gone up plating platinum or add material after adhering to ruthenium etc. on its surface.For example can add and adhere to platinum (Pt) back plating ruthenium (Ru), in oxygen atmosphere, it be burnt till again, and obtain above-mentioned electrode by calendering on titanium (Ti) sheet material.And above-mentioned electrode also can and burn till in oxygen atmosphere by electroplatinizing on titanium sheet material and obtain.In addition, firing temperature is all preferred 650 ℃~700 ℃.
Anode 32 and negative electrode 34 are connected and omit on the illustrated power supply, by being made by described power supply supply electric current in the mixture in the direct current feeding fermentation portion 40.Like this, if feed direct current in the mixture in fermentation portion 40, then lactic acid or water as liquid are moved in the direction (arrow A Fig. 1) from anode 32 side direction negative electrodes 34 sides by electro-osmotic effects.
As long as next door 36 can make the liquid (lactic acid) in the mixture pass through by also suppressing solid matters such as W-Gum, just can be any structure, can make for example netted.As the material that constitutes next door 36, so long as lactic acid etc. is had the to a certain degree material of patience, just can use and have no particular limits, consider to be preferably titanium (Ti) from the angle of rust-preventing characteristic.In addition, as hereinafter described, also can form next door 36 self with the metal that constitutes anode 32, and with described next door 36 self as anode 32.At this moment, the space that separates by next door 36 and with concentrated portion 38 forms fermentation portion.And then, also preferably use polyimide film etc.
Concentrate portion 38 and form, and be located at a side with negative electrode 34 by separate fermentor tank 30 inside with next door 36.In concentrated portion 38, because of the lactic acid of electro-osmotic effects by next door 36 stores in this.The lactic acid of below will be by next door 36 and moving to the portion that concentrates is called " high density lactic acid ".In addition, in concentrated portion 38, an end of vent pipe 42 is connected with an end of supply-pipe 44, and is formed on and concentrates the structure that portion 38 and lactic acid store the high density lactic acid that can circulate between jars 50.
One end of circulation tube 46 is connected in the fermentation portion 40 of fermentor tank 30.In addition, the other end of circulation tube 46 is connected on the mixing device 20, forms following structure, and unreacted W-Gum (starch) or milk-acid bacteria etc. in the fermentation portion 40 are supplied in the mixing device 20 once more, can utilize again.And then, in fermentation portion 40, being provided with and omitting illustrated relief outlet, formation can be discharged to the outer structure of device with the fermentation residue of the W-Gum after the fermentation etc.In addition, in the present embodiment, formed the mixture round-robin mode between mixing device 20 and fermentation portion 40 that makes, but described Recycle design is arbitrarily.
Lactic acid stores the structure of jar 50 can accept the supply of fermentation, isolated high density lactic acid in the fermentor tank 30, and stores this high density lactic acid.In addition, store in jars 50 at lactic acid, an end of vent pipe 42 and an end of supply-pipe 44 are connected respectively, can make high density lactic acid lactic acid store jars 50 and the concentrated portion 38 of fermentor tank 30 between circulation.Like this, by making high density lactic acid store circulation between the jar 50, the lactic acid that can further be concentrated in concentrated portion 38 and lactic acid.In addition, in the present embodiment, formed and made high density lactic acid round-robin mode between concentrated portion 38 and lactic acid store jars 50, but described Recycle design is arbitrarily.
Lactic acid vent pipe 52 is connected lactic acid and stores on jars 50, and formation can store high density lactic acid in jars 50 at lactic acid and is expelled to structure outside the device storing.
Lactic acid manufacturing process in the lactic acid manufacturing installation of the present invention is described.At first, supply to milk-acid bacteria, W-Gum and water etc. in the mixing device 20 and mix, import then in the fermentation portion 40 of fermentor tank 30.Keeping temperature to be roughly 40 ℃, the pH of mixture in the fermentation portion 40 is 5~6, the fermentation several hrs.At this moment, the mixture in the fermentation portion 40 circulates with for example per minute 10 quality % between itself and mixing device 20.
In fermentation portion 40, during fermenting mixture, in this mixture, feed direct current by anode 32 and negative electrode 34.As the volts DS of this moment, the angle that the lactic bacteria activity that causes from the free hydrochloric acid ion that produced by electrode etc. hinders is considered, is preferably 1.0V~4.0V, more preferably 1.2V~3.0V.Like this, the lactic acid that fermentation produces is gone up by electro-osmotic effects and at the sense of current (direction of the arrow A of Fig. 1) and is moved, and by storing behind the next door 36 in concentrated portion 38.At this moment, water also can move to concentrated portion 38, but because the translational speed of lactic acid is fast, thereby lactic acid is concentrated.In addition, be detained in the fermentation portion 40 under the situation of a certain amount of fermentation residue, discharge fermentation residue from omitting illustrated relief outlet.
Store high density lactic acid in concentrating portion 38 and store between the jar 50 at concentrated portion 38 and lactic acid and circulate, after further being concentrated, can obtain high density lactic acid by lactic acid vent pipe 52.In addition,, can be provided with concentration sensor, after reaching finite concentration or discharge lactic acid when above, perhaps can being formed on the circulation certain hour, discharge the such structure of lactic acid for the circulation of high density lactic acid.
Then, use Fig. 2 and Fig. 3 that the concrete mode of the fermentor tank that uses in the lactic acid manufacturing installation of the present invention is described.Fig. 2 is the sectional view of using for the concrete mode of the fermentor tank among explanation the present invention, and Fig. 3 is the explanatory view of using for the concrete mode of the fermentor tank among explanation the present invention.
As shown in Figure 2, the fermentor tank among the present invention can form tubular.In addition, be provided with the negative electrode 62 of tubular as shown in Figure 3 along inwall in the inside of tubular fermentor tank 60, and then side is provided with and has cancellated tubular anode next door 64 within it.In described mode, as shown in Figures 2 and 3, formed the portion 66 that concentrates by the space of negative electrode 62 and 64 encirclements of anode next door, only the space that is surrounded by the anode next door forms fermentation portion 68.
In tubular fermentor tank 60, further be provided with raw material supplying mouth 70 and circulation fluid supplying opening 72.Raw material supplying mouth 70 and fermentation portion 68 communicate, and formation can import raw material (mixture) structure of fermentation portion 68.In addition, the mixtures in the fermentation portion 68 can be discharged from raw material relief outlet 74 with certain proportion, and get back in the mixing device 20 among Fig. 1.Thus, will in fermentation portion 68, sneak in the mixture by unreacted W-Gum etc., thereby can utilize again.Circulation fluid supplying opening 72 be for make the lactic acid of high density lactic acid in Fig. 1 store jars 50 and concentrated portion 66 between circulation and being provided with, the high density lactic acid of supplying with by circulation fluid supplying opening 72 and newly deliver to lactic acid Fig. 1 by lactic acid relief outlet 76 simultaneously and store jars 50 to concentrating lactic acid that portion 66 moves from fermentation portion 68.
In tubular fermentor tank 60, for the lactic acid that produces by W-Gum and lactobacillus-fermented in the fermentation portion 68 in tubular anode next door 64, if feed direct current from negative electrode 62 and anode next door 64 to the mixture that contains these materials, then this lactic acid is moved to concentrated portion 66 by fermentation portion 68.Thus, can be from mixture separating lactic acid.Like this, by fermentor tank is formed tubular, can efficient carry out the separation of lactic acid well and concentrate.
In addition, above-mentioned in, explanation be the mode of only using a fermentor tank, but the present invention is not limited to this structure, also can be with the tank connected structure of a plurality of fermentations.
<polymerization process 〉
Then use Fig. 4~6 pair poly(lactic acid) manufacturing installation of the present invention to describe.Fig. 4 is the sketch that schematically illustrates the structure of poly(lactic acid) manufacturing installation of the present invention.As shown in Figure 4, poly(lactic acid) manufacturing installation 80 of the present invention constitutes by having mixing device 82, polymerization tank 90 and electro-dewatering jar 100.For poly(lactic acid) manufacturing installation 80, in mixing device 82, catalyzer is mixed with lactic acid, in polymerization tank 90, heat again and this mixture of dehydration polycondensation, and then, in electro-dewatering jar 100, dewater by electro-osmotic effects, thus the poly(lactic acid) that can obtain expecting.Poly(lactic acid) manufacturing installation of the present invention 80 is by connecting polymerization tank 90 and electro-dewatering jars 100 with circulation tube 116, with predefined number of times or time polymerization repeatedly, drying, can obtain having the poly(lactic acid) of the molecular weight of expectation.
Mixing device 82 is not particularly limited, and is the device with known mixing devices such as stirrers.Lactic acid and catalyzer are fed in the described mixing device 82.At this moment, the ratio of mixture of lactic acid in the mixture (q) and catalyzer (w) (mass ratio q: w) be preferably 100: 1 to 100: 10, more preferably 100: 3 to 100: 5.As above-mentioned catalyzer, so long as can be used for the catalyzer of acid by dehydrating lactic polycondensation, just can use and have no particular limits, preference is as with mass ratio being 50 quality % blended ruthenium oxide and titanium oxide.In addition, the weight average particle volume diameter as above-mentioned catalyzer is preferably 0.1 micron~1 micron.Mixing device 82 is used for lactic acid and the catalyst mix that will be supplied to, makes mixture, and this mixture is imported in polymerization tank 90.
The polycondensation of dewatering of lactic acid that polymerization tank 90 is supplied with by mixing device 82 by heating and mixture of catalysts.In polymerization tank 90, lactic acid can form the poly(lactic acid) of the molecular weight with expectation through the lactic acid polymerizes operation in two steps.The first step lactic acid polymerizes operation is the operation by lactic acid synthesis of oligonucleotides thing, and the Heating temperature of this moment preferably is roughly 110 ℃~160 ℃, more preferably 130 ℃~150 ℃.In addition, the second step lactic acid polymerizes operation is to connect the operation of oligopolymer with the poly(lactic acid) of synthetic molecular weight with expectation, and the Heating temperature of this moment preferably is roughly 110 ℃~140 ℃, more preferably 115 ℃~120 ℃.
In addition, as hereinafter described, heat lactic acid while stirring and carry out polyreaction in order to improve the polymerization efficiency polymerization tank 90 preferred whipping apptss that adopt.
In polymerization tank 90, be provided with lactic acid polymer vent pipe 92, the lactic acid polymer that is used for certain hour internal heating and the polycondensation of dewatering are obtained (contain oligopolymer, do not reach the poly(lactic acid) and the water of desired molecular weight) supplies to electro-dewatering jar 100.
In electro-dewatering jar 100, be built-in with at least one pair of electrode that forms by anode 102 and negative electrode 104, these electrodes are connected with the illustrated power supply of omission.In addition, separating between with next door 106 anodes 102 and negative electrode 104 in the jar of electro-dewatering jar 100, is boundary with next door 106, is provided with dehydration portion 108 in the side with negative electrode 104, and is provided with dehydrated 110 in the side with anode 102.The mixture of being supplied with by polymerization tank 90 is imported into dehydrated 110.
Anode 102 and negative electrode 104 preferably are made of platinum precious metals such as (Pt), preferably use the material after titanium (Ti) is gone up platinum plating or add material after adhering to ruthenium etc. on its surface.Anode 102 and negative electrode 104 are connected and omit on the illustrated power supply, can feed direct current to the lactic acid polymer in dehydrated 110 by supplied with electric current by described power supply.Like this, if the lactic acid polymer in dehydrated 110 feeds direct current, then the water that is included in the lactic acid polymer is moved in the direction (arrow B Fig. 4) from anode 102 side direction negative electrodes 104 sides by electro-osmotic effects.
As long as next door 106 can make the water in the mixture pass through by also suppressing solid matters such as poly(lactic acid), just can be any structure, can make for example netted.And, as the material that constitutes next door 106, so long as lactic acid etc. is had the to a certain degree material of patience, just can use and have no particular limits.In addition, also can form next door 106 self with the metal that constitutes anode 102, and with described next door 106 self as anode 102.At this moment, by next door 106 and form dehydrated portion with space that dehydration portion 108 separates.And then, also preferably use polyimide film etc.
Dehydration portion 108 forms by separate electro-dewatering jar 100 inside with next door 106, and is located at the side with negative electrode 104 of electro-dewatering jar 100.In dehydration portion 108, be connected with glycerine supply-pipe 112 and glycerine vent pipe 114, form glycerine and flow through in the dehydration portion 108 and carry out the round-robin structure.Absorbed by anhydrous glycerol and form aqueous glycerol from dehydrated 110 moisture that is transferred to dehydration portion 108, and discharge by dehydration portion 108.The aqueous glycerol that dehydration portion 108 discharges can be removed moisture by known method such as for example underpressure distillation, forms anhydrous glycerol and is reused.
One end of circulation tube 116 is connected on dehydrated 110 of electro-dewatering jar 100.And the other end of circulation tube 116 is connected on the polymerization tank 90, forms following structure: the poly(lactic acid) in dehydrated 110 circulates between polymerization tank 90 and electro-dewatering jar 100 until forming desired molecular weight.And then, in dehydrated 110, being provided with and omitting illustrated relief outlet, formation can be discharged to the poly(lactic acid) that reaches desired molecular weight the outer structure of device.In addition, above-mentioned relief outlet also can be located on the polymerization tank.Be not particularly limited as the material that constitutes polymerization tank 90 and electro-dewatering jar 100, but consider to be preferably titanium (Ti) from the angle of rust-preventing characteristic.
Describe at the poly(lactic acid) manufacturing process in the poly(lactic acid) manufacturing installation of the present invention.At first, after lactic acid and catalyzer are fed into and mix in the mixing device 82, be imported among dehydrated 110 of electro-dewatering jar 100.Import to lactic acid in dehydrated 110 in polymerization tank 90 after the dehydration polycondensation, electricity consumption water knockout 100 dewaters, and obtains the purpose poly(lactic acid) by carrying out described operation repeatedly with expectation number of times or certain hour.Carry out molecular weight that the number of times of described operation or time can consider the purpose poly(lactic acid) repeatedly and suitable the setting.At this moment, between polymerization tank 90 and electro-dewatering jar 100, circulate with for example per minute 10 quality %.
Temperature in the polymerization tank 90 is different in above-mentioned second step of the first step lactic acid polymerizes operation neutralization lactic acid polymerizes operation.At this moment, the change of the temperature in the polymerization tank 90 can change according to predefined number of times or time.In addition, in the present invention, carry out before the first step lactic acid polymerizes operation, preferably through too 110 ℃~120 ℃ operations that make the moisture evaporation in the lactic acid.
In electro-dewatering jar 100, feed direct current to lactic acid polymer by anode 102 and negative electrode 104.Volts DS as this moment is preferably 3.0V~6.0V, more preferably 4.0V~5.0V.Like this, the moisture that the lactic acid polymerizes reaction generates is gone up by electro-osmotic effects and at the sense of current (direction of the arrow B of Fig. 4) and is moved, and moves to dehydration portion 108 by next door 106.And, between polymerization tank 90 and electro-dewatering jar, circulate with the number of times or the time of expectation, can obtain being blended into the poly(lactic acid) of desired molecular weight.
Then, the polymerization tank that uses Fig. 5 to illustrate to use in the poly(lactic acid) manufacturing installation of the present invention and the concrete mode of electro-dewatering jar.Fig. 5 is the sectional view of using for the concrete pattern of polymerization tank among explanation the present invention and electro-dewatering jar.
As shown in Figure 5, tubular polymerization tank 120 constitutes by the built-in screw rod in inside (bar-shaped rotator) 126 at the cylindrical shell (hollow matrix) 124 of the hollow that is provided with lactic acid supply unit 122, and described screw rod 126 has spiral groove from a side direction opposite side (being the screw front end side) that is provided with lactic acid supply unit 122; And then be provided with lactic acid polymer outlet 128 at the opposite side (screw front end side) of the cylindrical shell 124 that is not provided with lactic acid supply unit 122, and, by making screw rod 126 rotations, in heating lactic acid, stir, stir down and the lactic acid polymer after the polymerization can be shifted output from lactic acid polymer outlet 128.The lactic acid polymer of being discharged by lactic acid polymer outlet 128 is imported in the electro-dewatering jar 150.In addition, a side that is provided with lactic acid supply unit 122 at screw rod 126 is provided with motor (drive unit) 130, screw rod 126 is connected with motor 130 by the not shown speed reduction gearing with former moving gear and follower gear, supplies with and can rotate from the electric power of power supply (not shown) by acceptance.
By the rotation of screw rod 126, the lactic acid that is supplied to goes on foot the temperature dehydration polycondensation of lactic acid polymerizes operation corresponding to the first step and second in the cylindrical shell inherence.In the outside of cylindrical shell 124, be provided for heating inner electricradiator 132 to cover cylindrical shell mode on every side, thereby can carry out heating equably inner barrel, described well heater 132 heats inside through barrel walls.
In addition, on tubular polymerization tank 120, be provided with lactic acid polymer introducing port 134, be used for the lactic acid polymer after 150 dehydrations of electro-dewatering jar is imported in the polymerization tank 120, can the round-robin structure thereby between tubular polymerization tank 120 and electro-dewatering jar 150, form poly(lactic acid).
In Fig. 5, electro-dewatering jar 150 is communicated with tubular polymerization tank 120 by the pipe arrangement that is connected lactic acid polymer outlet 128.As shown in Figure 5, electro-dewatering jar 150 is by constituting as lower unit: cylinder 156, and it at one end has lactic acid polymer supplying opening 152 and has dehydrate relief outlet 154 at the other end; Tubular polyimide film 158 cylindraceous, it is located at the inside of cylinder 156; And static mixer 160, its inside at tubular polyimide film 158 is provided with three sections in abutting connection with the agitating vane that is provided with, described blade can rotate as turning axle to be parallel to the axle center of inserting logical direction (direction of arrow C among Fig. 4), and the blade alternate opposite spin of adjacent setting, in the electro-dewatering jar 150, insert the logical lactic acid polymer of supplying with by lactic acid polymer supplying opening 152 on one side, Yi Bian make its reverse backflow and mixing in turn, thus carry out processed.In addition, the wall of cylinder 156 is made of titanium (Ti).
The tubular polyimide film 158 that is located at the inside of cylinder 156 has the thin reticulated structure of mesh, among lactic acid polymer and the water, water is seen through.The inside of cylinder 156 is boundary with tubular polyimide film 158, and the tubular polyimide film is inner to form dehydrated 162, is formed with dehydration portion 164 in the outside of tubular polyimide film 158.
In addition, on the wall of cylinder 156, be provided with to dehydration portion 164 and supply with the glycerine relief outlet 165 that anhydrous glycerol glycerine supplying opening of using 166 and the aqueous glycerol of discharging dehydration portion inside are used, carry out the round-robin structure in the dehydration portion 164 thereby formation glycerine is flowed through.
In electro-dewatering jar 150, the wall of static mixer 160 and cylinder 156 is connected with the illustrated power supply of omission respectively, and static mixer 160 constitutes anode electrodes, and cylinder 156 constitutes cathode electrodes.Therefore, if electric current flows in the mixture that is imported by tubular polymerization tank 120, then move in inboard direction laterally by the dissociated moisture of lactic acid polymer from cylinder 156 by electro-osmotic effects.The moisture that moves laterally from the inboard of cylinder 156 sees through tubular polyimide film 158 and moves to dehydration portion 164.164 supplies have anhydrous glycerol in dehydration portion, and the moisture that sees through tubular polyimide film 158 is absorbed by anhydrous glycerol, form aqueous glycerol and also are discharged to outside the electro-dewatering jar 150.Be discharged to electro-dewatering jar 150 outer aqueous glycerol and outside system, remove moisture, form anhydrous glycerol and also supply with by glycerine supplying opening 166 once more by appropriate means such as for example underpressure distillation.
The static mixer 160 that becomes electro-dewatering jar 150 anode electrodes for example has the structure of three sections agitating vane 160a~160c adjacency as shown in Figure 6, described agitating vane is made by the plating plate left handed twist or the right side being reversed (for example windup-degree is 90 °), and described plating plate further adds on its surface after titanium (Ti) is gone up plating platinum (Pt) and adheres to ruthenium (Ru) and form.Static mixer 160 is subjected to the hydrodynamicpressure of direction of arrow C and can rotates along the direction of reversing when lactic acid polymer is inserted the inside of logical cylinder 156.By the static mixer 160 of this spline structure is set in electro-dewatering jar 150, the moisture in the lactic acid polymer can be brought into play electro-osmotic effects effectively easily near anode, and can improve the dewatering efficiency of lactic acid polymer.
In addition, dehydrated lactic acid polymer is with circulations between tubular polymerization tank 120 and electro-dewatering jar 150 such as the number of times of expectation or times, until forming desired molecular weight in electro-dewatering jar 150.Dehydrated lactic acid polymer in electro-dewatering jar 150 is discharged from dehydrate relief outlet 154, is imported into once more in the tubular polymerization tank 120.
Like this, in order to form desired molecular weight, lactic acid polymer circulated between tubular polymerization tank 120 and electro-dewatering jar 150 with predefined number of times or time, for such lactic acid polymer, its poly(lactic acid) as desired molecular weight is discharged from the poly(lactic acid) relief outlet 136 of tubular polymerization tank 120.Like this, if use poly lactic acid polymerized device of the present invention, then compare and to make poly(lactic acid) with the low-yield and only about half of time with desired molecular weight with the situation that adopts decompression dehydration in the past.That is, can be with short period of time and the low-yield synthetic poly(lactic acid) of desired molecular weight that has, and can high-level efficiency and obtain having the poly(lactic acid) of enough molecular weight with the short period of time.
Like this, according to poly(lactic acid) manufacturing installation of the present invention, all can implement continuously from the polymerization that is generated to poly(lactic acid) of lactic acid, the easy of the miniaturization of equipment, cost degradation, operation and the minimizing of manufacturing cost become possibility.In addition, in above-mentioned, the mode of only using a polymerization tank and electro-dewatering jar respectively has been described, but the present invention being not limited to this structure, also can be the structure that connects a plurality of polymerization tanks and electro-dewatering jar.
Embodiment
Below, be described more specifically the present invention in an embodiment.But the present invention is not limited to embodiment.
Embodiment 1
1. the generation of lactic acid
The lactic acid manufacturing installation that use has Fig. 2 and tubular fermentor tank shown in Figure 3 generates lactic acid according to following step.
(1) modulation of raw material suspension liquid
Use mixing device that 30 mass parts W-Gums, 0.5 mass parts salt, 69.5 mass parts water were stirred 5 minutes with 150rpm, modulate the raw material suspension liquid.
(2) modulation of liquefying starch
95 ℃ to by the above-mentioned raw material suspension liquid boiling that obtains 15 minutes, modulate pasty state starch.Pasty state starch, 0.5 mass parts lime carbonate and the 0.1 mass parts starch liquefacation enzyme that 99.4 mass parts are obtained (trade(brand)name: コ Network ゲ Application T, big and change into (strain) system), with behind the acetate adjusting pH (pH=6~7), stirred 10 minutes in 90 ℃ temperature with 30rpm with mixing device again.Further in pH=6~7,90 ℃, the mixture that obtains was placed 60 minutes, modulated liquefying starch.
(3) modulation of starch saccharification
With 99.9 mass parts by the above-mentioned liquefying starch that obtains be cooled to be not higher than 70 ℃ after, add 0.1 mass parts starch and cut an enzyme (trade(brand)name: Network ラ イ ス one ゼ PL, big and change into (strain) system), with behind the acetate adjusting pH (pH=5~6), stirred 10 minutes in 65 ℃ with 50rpm with mixing device again.Further, the mixture that obtains was placed 60 minutes, modulated starch saccharification in 65 ℃, pH=5~6.
(4) generation of lactic acid
With 99.9 mass parts by the above-mentioned starch saccharification that obtains be cooled to be not higher than 45 ℃ after, add 0.1 mass parts milk-acid bacteria, stirred 10 minutes in 45 ℃ with 150rpm with mixing device A.At this moment, the pH of mixture is 5~6.
The mixture that obtains is imported the fermentor tank shown in Fig. 2 and Fig. 3.The limit feeds the direct current limit and ferments, and obtains the lactic acid of 20 quality %.At this moment, fermentation condition is: temperature is 40 ℃, and pH is 5~6, and the reaction times is 240 minutes, and osmosis voltage is direct current 2.4V.And mixture circulates between fermentor tank and mixing device A with per minute 10 quality %.
[evaluation]
To 1kg with the starch saccharification that obtains equally in above-mentioned 1. condition in, add the 1g milk-acid bacteria, use and embodiment 1 same fermentor tank is determined at 40 ℃ of relations that put on the concentration of lactic acid of interelectrode voltage of osmosis and generation.At this moment, be that 0V, 1.2V, 2.4V and 3.6V measure to osmosis voltage respectively.The results are shown among Fig. 7.
Fig. 7 is the chart of the relation between expression lactic acid concn and osmosis voltage.As shown in Figure 7, between electrode not (0V) during circulating current, lactic acid concn does not reach more than or equal to 5.6 quality %, yet when osmosis voltage was changed to 1.2V, concentration was increased to 16.3 quality % after 8 hours.And then when osmosis voltage was changed to 2.4V, the lactic acid concn after 8 hours was increased to 24.5 quality %.In contrast, when osmosis voltage was changed to 3.6V, the concentration of lactic acid that obtains was about 14 quality %.The result as can be known, as above-mentioned osmosis voltage preferably between 1.2V~3.0V.
2. poly(lactic acid) is synthetic
Use has the polymerization tank of tubular shown in Figure 5 and the lactic acid manufacturing installation of electro-dewatering jar generates lactic acid according to following step.
(1) drying process
Use mixing device that lactic acid and 0.5 mass parts of catalyst (with mass ratio 50 quality % blended ruthenium oxide and titanium oxide) of 99.5 mass parts by the above-mentioned concentration that obtains 20% stirred 10 minutes with 150rpm.At this moment, the pH of mixture is 3.5~4, and temperature is 90 ℃.Then, with the mixture that obtains 110 ℃~120 ℃ evaporation dryings 0.5 hour.At this moment, concentration of lactic acid is about 60 quality %.
(2) polymerization and dehydration procedure
Use polymerization tank shown in Figure 5 and electro-dewatering jar, the lactic acid and the mixture of catalysts that obtain are circulated between polymerization tank and electro-dewatering jar with per minute 10 quality %, carry out 240 minutes polymerization and dehydration simultaneously.At this moment, in the electro-dewatering jar, be that 4.8V feeds direct current to poly(lactic acid) with interelectrode osmosis voltage, dewater.In addition, for the temperature of polymerization tank, 90 minutes of beginning are set at 140 ℃~145 ℃, and remaining 150 minutes are set at 115 ℃~120 ℃.The weight-average molecular weight of measuring the poly(lactic acid) that obtains with dsc (DSC) is 120000.
[evaluation]
At the polymerization and the dehydration procedure of lactic acid, will use and the mode of the present invention of above-mentioned 2. same methods (initial stage lactic acid concn be 60 quality %, osmosis voltage be 120000, use polymerization tank and electro-dewatering jar shown in Figure 5 as 4.8V, terminal point poly(lactic acid) weight-average molecular weight) compares with the special mode (the initial stage lactic acid concn is that 60 quality %, reduced vacuum degree are that 0.08 (MPa), terminal point poly(lactic acid) weight-average molecular weight are 120000) of opening the decompression dehydration method of putting down in writing in the 2003-335850 communique in the past.The results are shown among Fig. 8.Fig. 8 is the polymerization temperature of polyreaction of expression poly(lactic acid) and the chart of the relation between the polymerization time.
As shown in Figure 8, when carrying out polymerization and dehydration by the mode of the present invention of having used the electroosmotic dewatering jar, the time that the first lactic acid polymerizes operation needs (T1 ') be approximately 20 minutes, the time that the second lactic acid polymerizes operation needs (T2 ') is approximately 160 minutes, thereby comprises that dry evaporization process is 120000 poly(lactic acid) just can obtain weight-average molecular weight in about 240 minutes.
Relative therewith, when the mode of use decompression dehydration method is in the past carried out polymerization and dehydration, the time (T1) that the first lactic acid polymerizes operation needs is approximately 30 minutes, the time (T2) that the second lactic acid polymerizes operation needs is approximately 390 minutes, thereby comprises that it is 120000 poly(lactic acid) that dry evaporization process needs obtained weight-average molecular weight in 480 minutes.Therefore, as described herein, compare, adopted the polymerization time of the present invention of osmosis formula water knockout approximately can obtain having the poly(lactic acid) of desired molecular weight with half the time with the situation of using decompression dehydration mode in the past.
In addition, known to Fig. 8, use under the situation of mode of the present invention, the polymerization temperature that the first lactic acid polymerizes operation (T1 ') needs is 137 ℃, the polymerization temperature that the second lactic acid polymerizes operation (T2 ') needs is 118 ℃, yet the polymerization temperature that the first lactic acid polymerizes operation (T1) needs is 145 ℃, the polymerization temperature that needs in the second lactic acid polymerizes operation (T2) is 123 ℃, can know, compare with the situation of using decompression dehydration mode in the past, can reduce by 4%~6% polymerization temperature under the situation of use mode of the present invention.
As mentioned above, according to the present invention, can provide can high-level efficiency and obtain having the poly(lactic acid) manufacture method of the poly(lactic acid) of desired molecular weight, obtain the lactic acid manufacturing installation of high density lactic acid and high-level efficiency and obtain having the poly(lactic acid) manufacturing installation of the poly(lactic acid) of enough molecular weight with the short period of time expeditiously with the short period of time.
In addition, by adopting poly(lactic acid) manufacture method of the present invention, lactic acid manufacturing installation and poly(lactic acid) manufacturing installation, can carry out continuously from the polymerization that is generated to poly(lactic acid) of lactic acid.And, also can realize equipment miniaturization, cost degradation, operation easy and reduce manufacturing cost.