Summary of the invention
In view of this; Technical problem to be solved by this invention is to provide a kind of starch composites; Starch composites provided by the invention is made up of the amylose starch of different molecular weight, has good processing properties, and the starch material that obtains through processing has the good mechanical performance.
The invention provides a kind of starch composites, comprising:
The HMW amylose starch of 90~100 weight parts, the molecular weight of said HMW amylose starch are 100000~999999, and the purity of said HMW amylose starch is 90%~100%;
The low molecular weight linear starch of 1~10 weight part, the molecular weight of said low molecular weight linear starch are 10000~90000, and the purity of said low molecular weight linear starch is 90%~100%;
The softening agent of 1~15 weight part.
Preferably, said HMW amylose starch prepares according to following method:
A) with carrying out coarse reduction after the cereal immersion, obtain coarse starch milk behind the separated plumule;
B) said coarse starch milk is carried out fine crushing, obtain milk of starch behind separating protein and the fiber;
C) in said milk of starch, add alkaline solution, form starch solution, said starch solution is 40 ℃~60 ℃;
D) be that the microfiltration membrane of 0.6 μ m~1.5 μ m is the said starch solution of filter media with the aperture, obtain amylose starch solution;
E) be the said amylose starch solution of filter media with the aperture less than the microfiltration membrane of 0.6 μ m, obtain the HMW amylose starch.
Preferably, said alkaline solution is sodium hydroxide solution or potassium hydroxide solution.
Preferably, said softening agent is glycerine or water.
The invention provides a kind of starch composites, comprising:
The HMW amylose starch of 80~90 weight parts, the molecular weight of said HMW amylose starch are 100000~999999, and the purity of said HMW amylose starch is 90%~100%;
The low molecular weight linear starch of 10~20 weight parts, the molecular weight of said low molecular weight linear starch are 10000~90000, and the purity of said low molecular weight linear starch is 90%~100%;
The softening agent of 1~15 weight part.
Preferably, the molecular weight of said HMW amylose starch is 150000~600000.
Preferably, the molecular weight of said low molecular weight linear starch is 20000~50000.
The present invention also provides a kind of starch composites, comprising:
The HMW amylose starch of 60~80 weight parts, the molecular weight of said HMW amylose starch are 100000~999999, and the purity of said HMW amylose starch is 90%~100%;
The low molecular weight linear starch of 20~40 weight parts, the molecular weight of said low molecular weight linear starch are 10000~90000, and the purity of said low molecular weight linear starch is 90%~100%;
The softening agent of 10~50 weight parts.
Preferably, said HMW amylose starch is 60~70 weight parts.
Preferably, said low molecular weight linear starch is 30~40 weight parts.
Compared with prior art; The present invention is that amylose starch more than 90% is a raw material with purity; The amylose starch of different molecular weight is made up; Obtain having the compsn of different processing characteristicies, have the different mechanical performance after the processing: the starch mixture as being made up of 90~100 weight part HMW amylose starchs and 1~10 weight part low molecular weight linear starch can be used as the injection grade starch material, through having the good mechanical performance after the injection moulding; And the starch composites of low molecular weight linear starch that comprises HMW amylose starch and 10~20 weight parts of 80~90 weight parts can be used as sheet material level starch material, has the good mechanical performance through after the extrusion moulding; And the starch composites of the low molecular weight linear starch of the HMW amylose starch of 60~80 weight parts and 20~40 weight parts can be used as film level starch material, through having the good mechanical performance behind blowing film forming or the casting film-forming.The present invention is a raw material with high-purity linear-chain starch directly, has reduced pulullan and has mixed the detrimentally affect that is brought with amylose starch, has improved the performance of starch material.Simultaneously; HMW amylose starch and low molecular weight linear starch that the present invention will have different performance make up, and improve the processing fluidity of starch composites, make it be suitable for different processing modes; Thereby obtain different starch materials, enlarged the application of starch at polymeric material field.In addition, starch composites provided by the invention also has edibility.
Embodiment
The present invention is that amylose starch more than 90% is a raw material with purity, and HMW amylose starch and low molecular weight linear starch are made up by different ratios, obtains having the compsn of different processing characteristicies, has the different mechanical performance after the processing.
The invention provides a kind of starch composites, comprising:
The HMW amylose starch of 90~100 weight parts, the molecular weight of said HMW amylose starch are 100000~999999, and the purity of said HMW amylose starch is 90%~100%;
The low molecular weight linear starch of 1~10 weight part, the molecular weight of said low molecular weight linear starch are 10000~90000, and the purity of said low molecular weight linear starch is 90%~100%;
The softening agent of 1~15 weight part.
Said starch composites comprises the HMW amylose starch of 90~100 weight parts and the low molecular weight linear starch of 1~10 weight part, the molecular weight broad, and processing fluidity is better, is suitable for injection moulding.Simultaneously, the HMW amylose content is higher in the said starch composites, and intensity, modulus and the thermostability of the injection grade starch material that obtains are all better.
The present invention also provides a kind of starch composites, comprising:
The HMW amylose starch of 80~90 weight parts, the molecular weight of said HMW amylose starch are 100000~999999, and the purity of said HMW amylose starch is 90%~100%;
The low molecular weight linear starch of 10~20 weight parts, the molecular weight of said low molecular weight linear starch are 10000~90000, and the purity of said low molecular weight linear starch is 90%~100%;
The softening agent of 1~15 weight part.
Said starch composites comprises the HMW amylose starch of 80~90 weight parts and the low molecular weight linear starch of 10~20 weight parts, is suitable for extrusion moulding and obtains sheet material level starch material.
The present invention also provides a kind of starch composites, comprising:
The HMW amylose starch of 60~80 weight parts, the molecular weight of said HMW amylose starch are 100000~999999, and the purity of said HMW amylose starch is 90%~100%;
The low molecular weight linear starch of 20~40 weight parts, the molecular weight of said low molecular weight linear starch are 10000~90000, and the purity of said low molecular weight linear starch is 90%~100%;
The softening agent of 10~50 weight parts.
Said starch composites comprises the HMW amylose starch of 60~80 weight parts and the low molecular weight linear starch of 20~40 weight parts, is suitable for extrusion moulding and obtains sheet material level starch material.In said starch composites, the HMW amylose starch is preferably 60~70 weight parts, and low molecular weight linear starch is preferably 20~30 weight parts.
In above-mentioned three kinds of starch composites provided by the invention; Except the blending ratio of HMW amylose starch, low molecular weight linear starch and softening agent is different, not other differences of HMW amylose starch, low molecular weight linear starch and softening agent itself.Exactly because and the blending ratio of each raw material is different, make the processing characteristics of the starch composites that obtains different, the performance of the starch material that obtains after the process processing is difference to some extent also.
According to the present invention, the molecular weight of said HMW amylose starch is 100000~999999, is preferably 150000~600000, more preferably 200000~500000, most preferably be 300000~500000; Its purity is more than 90%, more preferably more than 95%.
According to the present invention, the molecular weight of said low molecular weight linear starch is 10000~90000, is preferably 20000~70000, more preferably 20000~50000; Its purity is more than 90%, more preferably more than 95%.
Amylose starch according to the invention is meant well known to those skilled in the art only with α-1, and the glucose high polymer that the 4-glycosidic link connects is preferably cereal starch, and is concrete like W-Gum, pea starch and yam starch etc., more preferably W-Gum.According to the present invention, said HMW amylose starch and low molecular weight linear starch are preferably according to following method preparation:
A) with carrying out coarse reduction after the cereal immersion, obtain coarse starch milk behind the separated plumule;
B) said coarse starch milk is carried out fine crushing, obtain milk of starch behind separating protein and the fiber;
C) in said milk of starch, add alkaline solution, form starch solution, said starch solution is 40 ℃~60 ℃;
D) be that the microfiltration membrane of 0.6 μ m~1.5 μ m is the said starch solution of filter media with the aperture, obtain amylose starch solution;
E) be the said amylose starch solution of filter media with the aperture less than the microfiltration membrane of 0.6 μ m, obtain the HMW amylose starch.
According to the present invention, carry out coarse reduction after at first cereal being soaked, obtain coarse starch milk behind the separated plumule.According to the present invention, at first cereal is soaked, to break proteinic reticulated structure in the cereal, improve the permeability of cereal epidermis, the passivation plumule is so that separate plumule, protein, fiber etc. with starch.The present invention preferably uses sulfurous acid to soak, and the concentration of said sulfurous acid is preferably 0.1wt%~0.3wt%, more preferably 0.2wt%~0.25wt%; Said soak time is preferably 30h~60h, more preferably 36h~55h; Said soaking temperature is preferably 45 ℃~55 ℃, more preferably 49 ℃~53 ℃.In immersion process, sulfurous acid can destroy the reticulated structure of corn protein, the washing that helps starch with separate.
Cereal after soaking is carried out corase grind well known to those skilled in the art, and the purpose of roughly grinding is that cereal is ground, with germ separation.According to the present invention, the temperature of said corase grind is preferably 40 ℃~60 ℃, and the granularity of the coarse starch milk that obtains after the corase grind is preferably 20 orders~60 orders.Mixture after the corase grind is filtered can be with germ separation.
As carrying out fine grinding well known to those skilled in the art, the purpose of carrying out fine grinding is that protein and fiber and starch are separated to said thick starch in continuation.According to the present invention, the temperature of said fine grinding is preferably 40 ℃~60 ℃, and the granularity of the milk of starch that obtains after the fine grinding is preferably 150 orders~300 orders.Mixture after the fine grinding is carried out filtration well known to those skilled in the art can protein and fiber separation be obtained containing the milk of starch of amylose starch and pulullan.
After obtaining milk of starch, in said milk of starch, add alkaline solution, obtain starch solution.Amylose starch is dissolved in the higher solution of temperature, and pulullan is insoluble, therefore can said amylose starch be separated with pulullan through filtering.According to the present invention, said alkaline solution is preferably sodium hydroxide solution or potassium hydroxide solution, more preferably potassium hydroxide solution.The consumption of said alkaline solution is preferably 0.1%~10% of said milk of starch weight, and more preferably 1%~10%, most preferably be 1%~4%.The temperature of said starch solution is 40 ℃~60 ℃, and more preferably 45 ℃~55 ℃, the pH value is preferably 10~12.
After obtaining starch solution, be that the microfiltration membrane of 0.6 μ m~1.5 μ m is the said starch solution of filter media with the aperture, the insolubles that obtains is a pulullan, filtrates to be the solution of amylose starch.Continuation is that filtration medium filter with the aperture less than the microfiltration membrane of 0.6 μ m to said filtrating; Can the high-molecular weight amylose starch be separated with low-molecular-weight amylose starch; Insolubles is the HMW amylose starch, filtrates to be the solution of low molecular weight linear starch.To filtrate cooling, can obtain the high purity and low molecular weight amylose starch after centrifugal.In order to improve the separating effect of high-molecular weight amylose starch and low-molecular-weight amylose starch, before carrying out step e), the pH value of filtrate that preferably step d) is obtained transfers to 9~11.The present invention preferably uses hydrochloric acid that the filtrating that step d) obtains is carried out the adjusting of pH value.
After step d) and twice filtration of step e), the HMW amylose starch all is able to separate with low molecular weight linear starch, obtains high purity HMW amylose starch and high purity and low molecular weight amylose starch, and purity is all more than 90%.
Also comprise softening agent in three kinds of starch composites provided by the invention, the effect of said softening agent is the plasticity that increases the starch material that obtains after the processing.In order to make the starch material that obtains have edibility, said softening agent is preferably water or glycerine.
Compared with prior art, the present invention is a raw material with high-purity linear-chain starch directly, has reduced pulullan and has mixed the detrimentally affect that is brought with amylose starch, has improved the performance of starch material.Simultaneously; HMW amylose starch and low molecular weight linear starch that the present invention will have different performance make up, and improve the processing fluidity of starch composites, make it be suitable for different processing modes; Thereby obtain different starch materials, enlarged the application of starch at polymeric material field.
In order to further specify the present invention, starch composites provided by the invention is described in detail below in conjunction with embodiment.
Embodiment 1
The late-maturing corn in the Northeast that with the amylose content is 28wt% is a raw material, and the corn of results is air-dry, and water ratio is 14wt%.
In the 20L mass concentration was 0.25% sulfurous acid, 50 ℃ were soaked 50h with the 10kg corn soaking; Corn after soaking dropped in the stirrer roughly grind, obtain coarse starch milk after the slurry that obtains after the corase grind is crossed 40 mesh sieves; Coarse starch milk dropped into carry out fine grinding in the stirrer, the slurry that obtains after the fine grinding is crossed 200 mesh sieves, obtain milk of starch;
Get the 5kg milk of starch, adding 0.15kg mass concentration is 5% sodium hydroxide solution, obtains starch solution, and the temperature of starch solution is 45 ℃, and the pH value is 10; With the aperture is that the microporous membrane of 1.5 μ m is that filter membrane carries out the first time and filters, and with the double wave regular way the said thing that leaches is detected, and wherein the content of pulullan is 85wt%; In the time of 25 ℃ be that solvent carries out weight-average molecular weight with GPC to said pulullan and measures with the DMSO 99.8MIN., its MWD section is 1,600,000~1,800,000;
Using mass concentration is that 1% hydrochloric acid will filter the pH value of filtrate that obtains for the first time and transfer to 9; With the aperture is that the microporous membrane of 0.55 μ m is that filter membrane carries out the second time and filters; Detect filtering the thing that leaches that obtains for the second time with the double wave regular way; Its amylose content is 90wt%, in the time of 125 ℃ is that solvent carries out weight-average molecular weight with GPC and measures with the DMSO 99.8MIN., and its MWD section is 400,000~600,000;
Reduce to room temperature with filtering the filtrating that obtains for the second time; Spinning then; With the double wave regular way material that obtains is detected; Its amylose content is 92wt%, in the time of 25 ℃ is that solvent carries out weight-average molecular weight with GPC and measures with the DMSO 99.8MIN., and its MWD section is 30,000~50,000.
Embodiment 2
The early ripening maize that with the amylose content is Shandong, Hebei and the Henan of 28wt% is a raw material, and the corn of results is air-dry, and water ratio is 14wt%.
In the 20L mass concentration was 0.25% sulfurous acid, 50 ℃ were soaked 50h with the 10kg corn soaking; Corn after soaking dropped in the stirrer roughly grind, obtain coarse starch milk after the slurry that obtains after the corase grind is crossed 40 mesh sieves; Coarse starch milk dropped into carry out fine grinding in the stirrer, the slurry that obtains after the fine grinding is crossed 200 mesh sieves, obtain milk of starch;
Get the 5kg milk of starch, adding 0.2kg mass concentration is 5% sodium hydroxide solution, obtains starch solution, and the temperature of starch solution is 50 ℃, and the pH value is 12; With the aperture is that the microporous membrane of 1.2 μ m is that filter membrane carries out the first time and filters, and with the double wave regular way the said thing that leaches is detected, and wherein the content of pulullan is 87%; In the time of 25 ℃ be that solvent carries out weight-average molecular weight with GPC to said pulullan and measures with the DMSO 99.8MIN., its MWD section is 1,800,000~2,000,000;
Using mass concentration is that 1% hydrochloric acid will filter the pH value of filtrate that obtains for the first time and transfer to 10; With the aperture is that the microporous membrane of 0.45 μ m is that filter membrane carries out the second time and filters; Detect filtering the thing that leaches that obtains for the second time with the double wave regular way; Its amylose content is 92wt%, in the time of 25 ℃ is that solvent carries out weight-average molecular weight with GPC and measures with the DMSO 99.8MIN., and its MWD section is 180,000~200,000;
Reduce to room temperature with filtering the filtrating that obtains for the second time; Spinning then; With the double wave regular way material that obtains is detected; Its amylose content is 92wt%, in the time of 25 ℃ is that solvent carries out weight-average molecular weight with GPC and measures with the DMSO 99.8MIN., and its MWD section is 50,000~60,000.
Embodiment 3
With the molecular weight of 90kg embodiment 1 preparation is that the molecular weight of 400,000~600,000 amylose starch, 1kg embodiment 1 preparation is that 30,000~50,000 amylose starch and 15kg glycerine are behind the blender premix; Send into injection moulding machine material mouth, injection obtains smooth-going batten during 120 ℃ of temperature outs.
Said batten is carried out Mechanics Performance Testing, and its tensile strength is 26MPa, and elongation at break is 90%, and the injection moulding shrinking percentage is 6 ‰, and flexural strength is 30MPa, and notched Izod impact strength is 100kJ/m
2
Embodiment 4
With the molecular weight of 95kg embodiment 2 preparation is that the molecular weight of 180,000~200,000 amylose starch, 5kg embodiment 2 preparations is that 50,000~60,000 amylose starch and 15kg glycerine are behind the blender premix; Send into injection moulding machine material mouth, injection obtains smooth-going batten during 120 ℃ of temperature outs.
Said batten is carried out Mechanics Performance Testing, and its tensile strength is 25MPa, and elongation at break is 98%, and the injection moulding shrinking percentage is 9 ‰, and flexural strength is 28MPa, and notched Izod impact strength is 86kJ/m
2
Embodiment 5
It with the molecular weight of 85kg embodiment 2 preparation 180,000~200,000 amylose starch; The molecular weight of 10kg embodiment 1 preparation is that 30,000~50,000 amylose starch and 15kg water are behind the blender premix; Send into forcing machine material mouth, extrude smooth-going sheet material exemplar during 120 ℃ of temperature outs.
Said sheet material exemplar is carried out Mechanics Performance Testing, and its tensile strength is 24MPa, and elongation at break is 99%, and flexural strength is 26MPa, and notched Izod impact strength is 96kJ/m
2
Embodiment 6
It with the molecular weight of 80kg embodiment 1 preparation 400,000~600,000 amylose starch; The molecular weight of 10kg embodiment 2 preparation is that 50,000~60,000 amylose starch and 15kg glycerine are behind the blender premix; Send into forcing machine material mouth, extrude smooth-going sheet material exemplar during 120 ℃ of temperature outs.
Said sheet material exemplar is carried out Mechanics Performance Testing, and its tensile strength is 28MPa, and elongation at break is 115%, and flexural strength is 30MPa, and notched Izod impact strength is 85kJ/m
2
Embodiment 7
With the molecular weight of 65kg embodiment 1 preparation is that the molecular weight of 400,000~600,000 amylose starch, 25kg embodiment 2 preparations is that 50,000~60,000 amylose starch and 45kg glycerine are behind the blender premix; Send into forcing machine material mouth, blown film obtains smooth-going exemplar during 120 ℃ of temperature outs.
Said exemplar is carried out Mechanics Performance Testing, and its tensile strength is 30MPa, and elongation at break is 120%.
Embodiment 8
With the molecular weight of 55kg embodiment 1 preparation is that the molecular weight of 400,000~600,000 amylose starch, 15kg embodiment 2 preparations is that the molecular weight of 180,000~200,000 amylose starch, 30kg embodiment 2 preparations is that 50,000~60,000 amylose starch and 30kg glycerine are behind the blender premix; Send into forcing machine material mouth, blown film obtains smooth-going exemplar during 120 ℃ of temperature outs.
Said exemplar is carried out Mechanics Performance Testing, and its tensile strength is 26MPa, and elongation at break is 120%.
Embodiment 9
With the molecular weight of 70kg embodiment 1 preparation is that the molecular weight of 400,000~600,000 amylose starch, 25kg embodiment 2 preparations is that 50,000~60,000 amylose starch and 30kg glycerine are behind the blender premix; Send into casting machine material mouth, curtain coating obtains smooth-going exemplar for 50 ℃ during 120 ℃ of temperature outs.
Said exemplar is carried out Mechanics Performance Testing, and its tensile strength is 22MPa, and elongation at break is 110%.
Embodiment 10
With the molecular weight of 60kg embodiment 1 preparation is that the molecular weight of 400,000~600,000 amylose starch, 5kg embodiment 2 preparations is that the molecular weight of 180,000~200,000 amylose starch, 25kg embodiment 2 preparations is that 50,000~60,000 amylose starch and 35kg glycerine are behind the blender premix; Send into casting machine material mouth, curtain coating obtains smooth-going exemplar for 50 ℃ during 120 ℃ of temperature outs.
Said exemplar is carried out Mechanics Performance Testing, and its tensile strength is 25MPa, and elongation at break is 100%.
The explanation of above embodiment just is used for helping to understand method of the present invention and core concept thereof.Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention, can also carry out some improvement and modification to the present invention, these improvement and modification also fall in the protection domain of claim of the present invention.