WO2019082684A1 - Polylactic acid bottle separation and recovery method - Google Patents
Polylactic acid bottle separation and recovery methodInfo
- Publication number
- WO2019082684A1 WO2019082684A1 PCT/JP2018/038035 JP2018038035W WO2019082684A1 WO 2019082684 A1 WO2019082684 A1 WO 2019082684A1 JP 2018038035 W JP2018038035 W JP 2018038035W WO 2019082684 A1 WO2019082684 A1 WO 2019082684A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- polylactic acid
- bottles
- bottle
- peak
- absorption
- Prior art date
Links
- 229920000747 poly(lactic acid) Polymers 0.000 title claims abstract description 70
- 239000004626 polylactic acid Substances 0.000 title claims abstract description 70
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000000926 separation method Methods 0.000 title abstract description 23
- 238000011084 recovery Methods 0.000 title abstract description 7
- 238000010521 absorption reaction Methods 0.000 claims abstract description 44
- 238000005259 measurement Methods 0.000 claims abstract description 16
- 229920003023 plastic Polymers 0.000 claims description 46
- 239000004033 plastic Substances 0.000 claims description 46
- 230000009102 absorption Effects 0.000 claims description 41
- 239000002699 waste material Substances 0.000 claims description 18
- 230000014509 gene expression Effects 0.000 claims description 3
- 239000010924 used plastic bottle Substances 0.000 abstract 2
- 230000001747 exhibiting effect Effects 0.000 abstract 1
- -1 polyethylene terephthalate Polymers 0.000 description 28
- 229920000139 polyethylene terephthalate Polymers 0.000 description 26
- 239000005020 polyethylene terephthalate Substances 0.000 description 26
- 239000004743 Polypropylene Substances 0.000 description 23
- 229920001155 polypropylene Polymers 0.000 description 23
- 239000004698 Polyethylene Substances 0.000 description 21
- 238000012937 correction Methods 0.000 description 21
- 229920000573 polyethylene Polymers 0.000 description 21
- 239000000463 material Substances 0.000 description 20
- 238000000862 absorption spectrum Methods 0.000 description 16
- 238000006243 chemical reaction Methods 0.000 description 16
- 238000001228 spectrum Methods 0.000 description 16
- 239000004800 polyvinyl chloride Substances 0.000 description 14
- 238000002835 absorbance Methods 0.000 description 13
- 239000004793 Polystyrene Substances 0.000 description 11
- 229920001432 poly(L-lactide) Polymers 0.000 description 11
- JVTAAEKCZFNVCJ-REOHCLBHSA-N L-lactic acid Chemical compound C[C@H](O)C(O)=O JVTAAEKCZFNVCJ-REOHCLBHSA-N 0.000 description 9
- 238000012545 processing Methods 0.000 description 9
- 238000004064 recycling Methods 0.000 description 9
- 239000011347 resin Substances 0.000 description 9
- 229920005989 resin Polymers 0.000 description 9
- 230000005484 gravity Effects 0.000 description 7
- 230000003287 optical effect Effects 0.000 description 7
- 229920000915 polyvinyl chloride Polymers 0.000 description 7
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 6
- 238000004364 calculation method Methods 0.000 description 5
- JVTAAEKCZFNVCJ-UWTATZPHSA-N D-lactic acid Chemical compound C[C@@H](O)C(O)=O JVTAAEKCZFNVCJ-UWTATZPHSA-N 0.000 description 4
- 229940022769 d- lactic acid Drugs 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 229920002223 polystyrene Polymers 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 239000004310 lactic acid Substances 0.000 description 3
- 235000014655 lactic acid Nutrition 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000012935 Averaging Methods 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 2
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 2
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 2
- 229920002472 Starch Polymers 0.000 description 2
- 229920000704 biodegradable plastic Polymers 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229910052733 gallium Inorganic materials 0.000 description 2
- 230000009477 glass transition Effects 0.000 description 2
- 229910052736 halogen Inorganic materials 0.000 description 2
- 150000002367 halogens Chemical class 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 2
- 238000002329 infrared spectrum Methods 0.000 description 2
- 235000019698 starch Nutrition 0.000 description 2
- 239000008107 starch Substances 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- 239000002028 Biomass Substances 0.000 description 1
- 244000205754 Colocasia esculenta Species 0.000 description 1
- 235000006481 Colocasia esculenta Nutrition 0.000 description 1
- 102000004190 Enzymes Human genes 0.000 description 1
- 108090000790 Enzymes Proteins 0.000 description 1
- 241000233866 Fungi Species 0.000 description 1
- 240000003183 Manihot esculenta Species 0.000 description 1
- 235000016735 Manihot esculenta subsp esculenta Nutrition 0.000 description 1
- 244000061456 Solanum tuberosum Species 0.000 description 1
- 235000002595 Solanum tuberosum Nutrition 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 240000008042 Zea mays Species 0.000 description 1
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 1
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229920003232 aliphatic polyester Polymers 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 235000005822 corn Nutrition 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000000539 dimer Substances 0.000 description 1
- 238000012850 discrimination method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- JJTUDXZGHPGLLC-UHFFFAOYSA-N lactide Chemical compound CC1OC(=O)C(C)OC1=O JJTUDXZGHPGLLC-UHFFFAOYSA-N 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 238000000491 multivariate analysis Methods 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000013502 plastic waste Substances 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 238000007151 ring opening polymerisation reaction Methods 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
- B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
- B07C5/34—Sorting according to other particular properties
- B07C5/342—Sorting according to other particular properties according to optical properties, e.g. colour
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/359—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using near infrared light
Definitions
- the present invention relates to a method for separating and collecting biomass-derived polylactic acid bottles from plastic bottle wastes.
- PLA polylactic acid
- Polylactic acid is a polymer using L-lactic acid as a monomer obtained from starch starch such as corn, tuberous roots such as cassava, tubers such as potato, or starchy lactic acid fermented from corms such as taro. Generally, it is produced from the direct polycondensation method or the ring-opening polymerization method of lactide which is a dimer.
- Such polylactic acid is a plastic derived from agricultural products, so unlike conventional plastics relying on petroleum resources, there is no risk that its use will lead to resource depletion.
- a global environment-friendly resin since it is decomposed into water and carbon dioxide by microorganisms in the natural world, it is known as a global environment-friendly resin as a completely recycled material that is produced from plants and returned to plants without accumulation of carbon dioxide in the atmosphere. ing.
- polylactic acid is highly transparent, and its glass transition temperature is 60 ° C., which is close to the glass transition temperature Tg (70 ° C.) of polyethylene terephthalate (PET), and its specific gravity is 1.27 g / cm for polyethylene terephthalate.
- PET polyethylene terephthalate
- Polylactic acid is similar to 1.24 g / cm 3 (amorphous / crystalline), while it is 3 (amorphous) to 1.33 g / cm 3 (crystalline). Because the strength is also comparable to PET, it is difficult to distinguish polylactic acid products from polyethylene terephthalate products.
- plastic waste discarded from home is burnt or buried.
- plastic products such as bottles that can be easily separated have been promoted to be reused by mechanical recycling, chemical recycling, and other recycling, and separate collection of bottles has been promoted.
- polyethylene terephthalate PET
- PS polystyrene
- PP polypropylene
- PVC polyvinyl chloride
- PE polyethylene
- PET polyethylene terephthalate
- PS polystyrene
- PP polypropylene
- PVC polyvinyl chloride
- PE polyethylene
- PET polyethylene terephthalate
- PS polystyrene
- PP polypropylene
- PVC polyvinyl chloride
- PE polyethylene
- Patent Documents 1 to 3 and the like propose a method of sorting plastics, but none of them are unsatisfactory for identification and separation of polylactic acid bottles.
- separation using specific gravity or optical separation using near infrared light / infrared light is used.
- the optical separation method is a method that has been proposed in recent years, but in many cases it is necessary to pre-treat a process such as mechanical crushing or a flaking process due to pressure. It has hardly been studied as a means for identifying and recovering plastic.
- an object of the present invention is to provide a method for identifying and separately collecting polylactic acid bottles from plastic bottle waste collected in a bottle collection box or the like.
- a method of separately collecting polylactic acid bottles from plastic bottle waste The plastic bottle waste was subjected to near-infrared measurement in the wavelength range of 1600 to 1800 nm, and two absorption peaks of the short wavelength side absorption peak observed near 1680 nm and the long wavelength side absorption peak observed near 1718 nm A method is provided for recovering peak bottle waste as polylactic acid bottles.
- the method of the present invention focuses on the near infrared absorption of polylactic acid, measures the near infrared absorption spectrum of the recovered plastic bottle, and detects the short wavelength side absorption peak observed around 1680 nm which is characteristic of polylactic acid What shows two absorption peaks with the long wavelength side absorption peak observed near 1718 nm is identified as a polylactic acid bottle, and it separates and collects from another bottle. That is, polylactic acid bottles from other general purpose plastic bottles, such as PET bottles, polystyrene bottles, polypropylene bottles, polyethylene bottles, polyvinyl chloride bottles, etc., are identified by identifying two infrared absorption peaks as polylactic acid bottles. Can be separated and recovered, which makes it possible to recycle polylactic acid.
- the figure which shows the correction spectrum (the largest peak intensity is normalized to 1) which carried out A / D conversion and baseline correction about the near-infrared absorption spectrum about PP.
- the figure which shows the correction spectrum (maximum peak intensity is normalized to 1) which carried out A / D conversion and baseline correction about the near-infrared absorption spectrum about PVC.
- the method of the present invention separates and recovers a bottle showing two near infrared absorption spectra (a short wavelength side absorption peak observed near 1680 nm and a long wavelength side absorption peak observed near 1718 nm) as a polylactic acid bottle . That is, although the absorption spectrum in the near-infrared region (1600 to 1800 nm) of various plastics is shown in FIG. 1, as understood from this FIG. 1, polylactic acid is observed at around 1680 nm It has a short wavelength side absorption peak and a long wavelength side absorption peak observed around 1718 nm.
- baseline correction can be performed by linearly approximating valley-valley in the range of the short wavelength side end (1600 nm) and the long wavelength side end (1800 nm) of the measured near infrared absorption spectrum, Such a correction makes it possible to clearly distinguish the absorption spectra for various plastics. Further, by performing the above-described baseline correction, baseline drift correction can also be automatically performed, and peak sharpening and calculation accuracy of the absorbance ratio can be improved.
- FIGS. 2 to 7 show absorption spectra of various plastics subjected to baseline correction and peak sharpening as described above, it is possible to reliably identify various plastics by such correction.
- the polylactic acid bottle can be identified, separated and recovered from the presence of the above-mentioned short wavelength side absorption peak (around 1680 nm) and long wavelength side absorption peak (around 1718 nm).
- the short wavelength side absorption peak (around 1680 nm) and the long wavelength side absorption peak (around 1718 nm) Formulas (1) and (2): I S ⁇ I L (1) 1.2 ⁇ I L / I S ⁇ 3.0 (2)
- I S is the intensity of the absorption peak on the short wavelength side
- I L is the intensity of the absorption peak on the long wavelength side
- the absorption spectrum can be clarified by the above-described baseline correction, peak sharpening, and the like, and bottle waste free from contaminants and the like can be identified as a polylactic acid bottle.
- the resin forming the bottle is either poly-L-lactic acid or poly-D-lactic acid which is an optically active isomer. It may also be, for example, a mixture of poly-L-lactic acid and poly-D-lactic acid. Usually, as long as 95% by mass or more of the resin forming the bottle is poly-L-lactic acid and / or poly-D-lactic acid, even if other resins are blended, the above two absorption peaks , Poly lactic acid bottle is determined.
- the observation peak may cause saturation in transmission method measurement because the thickness of the bottle is usually large, etc., and it may not be applied as the original data of the arithmetic processing. It is possible. Also, there are cases where the observed spectrum is not suitable for calculation due to the change of the spectrum shape due to the label of the bottle or the like. Therefore, the measurement method by the reflection method is suitably adopted.
- the positions of the near infrared light source and the condensing optical system are adjusted according to the size of the input bottle in order to identify and separate the material of bottles different in size from 350 mL to 2 L. It is preferable to have a mechanism for adjusting automatically.
- a bottle inserted from a bottle insertion port is allowed to stand along an inclined surface provided for allowing the bottle to stand, and after observing the distance to the mouth with a CCD camera based on the bottom position reference, near red
- a method of automatically setting the position of the light irradiation light and the position of the focusing optical system is applied.
- a method of interlocking the optical system to selectively emit near infrared light and collect (receive) near infrared light on the shoulder and bottom calculated from the distance between the bottle bottom and the mouth The method of adjusting the near-infrared light which generate
- a device for identifying plastic materials based on near-infrared light includes a near-infrared light source using a halogen lamp, and a light-receiving element (detection from Pbs and InGaAs (indium gallium element) near infrared light condensed by a condensing optical system)
- the detection signal is amplified and digitally converted by an amplifier and A / D conversion (analog / digital conversion), and then processed by a personal computer to perform material identification.
- the near-infrared light spectrum is observed as data points of 200 points to 20000 points in the wavelength range of 1600 nm to 1800 nm, and after measurement of spatial resolution 1.0 nm to 0.01 nm, A / D change processing changes by first derivative. Calculate the curve point. (At least two peaks are observed using an algorithm that identifies two points (two peak components), but if only one point (one peak) is observed, it is recognized as one point.) 1600 nm The peak intensity and the peak intensity at 1,800 nm are linearly corrected, and after baseline correction, it is preferable to perform normalization processing with the peak intensity at 1 for the peak with the largest peak intensity, and perform noise removal and peak sharpening processing is there.
- the material is identified as a polylactic acid material, and collected in a collection box dedicated to polylactic acid bottles.
- variable (x, y) data after A / D conversion is data in which x indicates the wavelength (nm) and y indicates the intensity (I: intensity), and the peak determined with the inflection point of the first derivative as the peak top
- the remaining peak components are normalized to 0, leaving two points before and after the center wavelength (nm) of the peak wavelength. In this case, no peak is recognized for peak components not at the inflection point in the first derivative, and 0 standard
- the absorbance ratio can be calculated using the bivariate values (x, y) of the strongest peak component and the second peak component obtained as described above.
- the absorbance ratio is calculated from the intensities of the peaks at 1680 nm and 1718 nm, respectively, and thereby the conditional expression (1) described above It can be determined whether or not (2) is satisfied.
- the algorithm used for the calculation can calculate the absorbance ratio (I L / I S ) by setting the intensity of the long wavelength side peak component to be divided by the intensity of the short wavelength side peak component.
- the absorbance ratio (I L / I S ) is in the range of 1.2 to 3.0, and polylactic acid bottles are more accurately identified and separated and recovered from the numerical value range of this absorbance ratio. be able to.
- variable values of the near-infrared spectrum standardized by the above-mentioned method have the advantage of improving baseline waviness and drift, which are a problem in spectroscopy measurement and calculation thereof, and facilitating numerical analysis, and label objects And separation of peaks derived from contamination components such as residual contents, and the separation and collection accuracy of bottle identification is improved.
- even in the case of identifying and separating plastic materials using the absorbance ratio since the accuracy of the calculated value itself is improved, it can be used as a system for identifying and separating bottle materials with higher accuracy.
- the stick spectrum obtained by the above method is one peak standardized at 1655 nm, it is collected as a polyethylene terephthalate bottle (PET) in a dedicated collection box.
- PET polyethylene terephthalate bottle
- PS polystyrene
- Other plastic bottles C Bottles other than polylactic acid use commercially available bottles of similar size. After discarding the contents, it was lightly rinsed and used.
- the above polylactic acid (PLLA or PDLA) was injection molded into a preform mold having a mold temperature of 15 ° C. in an injection molding machine at a temperature of 190 ° C. to 240 ° C. It was created. Then, the preform was reheated to 90 ° C. with an infrared heater and blow molded into a 500 ml volume bottle with a blow mold having a mold temperature of 85 ° C. to obtain the above polylactic acid bottles A and B.
- a light receiving element (detecting a near infrared light source using a halogen lamp and a near infrared light collected by a light collection optical system adjacent to a dark room part of a slope where the bottle can be placed) made of InGaAs (indium gallium element) Container collection box to be detected by The detection signal was subjected to digital processing through an amplifier and A / D conversion (analog / digital conversion) and then processed by a personal computer.
- the light source and the light receiver were installed at six arbitrary positions in total, two at the front and back, centering on the bottle at the shoulder and the bottom.
- the measurement is integrated 20 times, and the detection signal obtained can be detected in the polylactic acid bottle by transmitting the signal to the personal computer after passing through the amplifier circuit and A / D converter, performing averaging processing, baseline correction, calculation.
- the air was discharged into a polylactic acid-only box of a collection box divided into a plurality of parts.
- the collection box prepared six collection boxes of polylactic acid (PLLA) and polyethylene terephthalate (PET), polyvinyl chloride (PVC), polystyrene (PS) and polypropylene (PP), and polyethylene (PE).
- Example 2 Five polylactic acid bottles B (PDLA), three PET bottles, three PVC bottles, three PS bottles, three PP bottles, three PE bottles (total 20 bottles) Randomly colored bottles near the red separation box It was introduced into the outside measurement room. In this case, the spectrum information after A / D conversion was used to identify, separate, and collect the observed wavelength. The results are shown in Table 1
- Example 3 Near-infrared measurement room of the bottle separation and collection box at random: 5 polylactic acid bottles A, 3 PET bottles, 3 PVC bottles, 3 PS bottles, 3 PP bottles, 3 PE bottles (20 total) Put in the In this case, it is a bottle in which two components of 1680 nm and 1718 nm are observed (identified) using spectrum information after A / D conversion, and peak intensities of long wavelength peak component intensity and short wavelength peak component intensity Arithmetic values of the ratio (absorbance ratio I L / I S ) were calculated, and recognition was performed using the observation wavelength and multivariate analysis using the absorbance ratio. The results are shown in Table 1.
- Wavelength analysis of polylactic acid bottles has not been performed by the material discrimination analysis method based on the near infrared wavelength, which has been proposed conventionally, and the accuracy of separation and recovery is insufficient only by the discrimination method by wavelength discrimination . Although the cause has not been completely elucidated completely, it is presumed that residual content and noise derived from the label are related.
- polylactic acid bottles are accurately separated from various plastic bottle wastes by using absorption peaks specific to two polylactic acids in a predetermined near infrared region It can be recovered, and recycling of polylactic acid and other resins can be effectively performed.
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- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Biochemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
- Sorting Of Articles (AREA)
Abstract
The polylactic acid bottle separation and recovery method according to the present invention is a method for separating and recovering polylactic acid bottles from used plastic bottles, the method being characterized in that near-infrared measurement is performed upon the used plastic bottles in a wavelength range of 1,600–1,800 nm, and used bottles exhibiting two absorption peaks, a short-wavelength absorption peak observed around 1,680 nm and a long-wavelength absorption peak observed around 1,718 nm, are recovered as polylactic acid bottles.
Description
本発明は、バイオマス由来のポリ乳酸ボトルを、プラスチック製ボトル廃棄物から分別回収する方法に関するものである。
The present invention relates to a method for separating and collecting biomass-derived polylactic acid bottles from plastic bottle wastes.
プラスチックの理想的廃棄という観点から、自然界で消滅するプラスチックが注目されてきており、中でも真菌類やバクテリアが体外に放出する酵素の作用で炭酸ガスに分解する生分解性プラスチックが注目されている。このような生分解性プラスチックの中でも、工業的に量産され入手が容易な、環境に優しい脂肪族ポリエステルとして、特にポリ乳酸（ＰＬＡ）が各種の用途に使用されている。
From the viewpoint of ideal disposal of plastic, plastic that disappears in the natural world has attracted attention, and in particular, biodegradable plastic that decomposes into carbon dioxide by the action of enzymes released from fungi and bacteria outside the body has attracted attention. Among such biodegradable plastics, polylactic acid (PLA) is used in various applications as an environmentally friendly aliphatic polyester which is industrially mass-produced and easily available.
ポリ乳酸は、トウモロコシなどの穀物澱粉や、キャッサバなどの塊根類、ジャガイモなどの塊茎類、または、タロイモなどの球茎類の澱粉質の乳酸発酵物から得られるＬ－乳酸をモノマーとした重合体で、一般にその直接重縮合法やダイマーであるラクタイドの開環重合法から製造される。このようなポリ乳酸は、農産物を原料とするプラスチックであることから、石油資源に依存する従来プラスチックと異なり、その使用が資源の枯渇化をもたらすおそれもない。また、自然界の微生物により、水と炭酸ガスに分解されることから、植物から生まれ植物に帰る完全リサイクル型の素材として、大気中への炭酸ガスの蓄積がなく、地球環境に優しい樹脂として知られている。
Polylactic acid is a polymer using L-lactic acid as a monomer obtained from starch starch such as corn, tuberous roots such as cassava, tubers such as potato, or starchy lactic acid fermented from corms such as taro. Generally, it is produced from the direct polycondensation method or the ring-opening polymerization method of lactide which is a dimer. Such polylactic acid is a plastic derived from agricultural products, so unlike conventional plastics relying on petroleum resources, there is no risk that its use will lead to resource depletion. In addition, since it is decomposed into water and carbon dioxide by microorganisms in the natural world, it is known as a global environment-friendly resin as a completely recycled material that is produced from plants and returned to plants without accumulation of carbon dioxide in the atmosphere. ing.
しかしながら、ポリ乳酸は、高透明で、且つ、ガラス転移転温度が６０℃とポリエチレンテレフタレート（ＰＥＴ）のガラス転移点温度Ｔｇ（７０℃）点に近く、比重も、ポリエチレンテレフタレートが１．２７ｇ／ｃｍ３（非晶）～１．３３ｇ／ｃｍ３（結晶）であるのに対し、ポリ乳酸は１．２４ｇ／ｃｍ３（非晶・結晶）と類似している、更に、延伸成形品の機械的強度もＰＥＴと同等であることから、ポリ乳酸製品をポリエチレンテレフタレート製品と区別することが困難である。
However, polylactic acid is highly transparent, and its glass transition temperature is 60 ° C., which is close to the glass transition temperature Tg (70 ° C.) of polyethylene terephthalate (PET), and its specific gravity is 1.27 g / cm for polyethylene terephthalate. Polylactic acid is similar to 1.24 g / cm 3 (amorphous / crystalline), while it is 3 (amorphous) to 1.33 g / cm 3 (crystalline). Because the strength is also comparable to PET, it is difficult to distinguish polylactic acid products from polyethylene terephthalate products.
一般に、家庭から廃棄されるプラスチックゴミの多くは、燃焼処分、または、埋め立処分されている。近年、分離が容易なボトルなどのプラスチック製品は、メカニカルリサイクルやケミカルリサイクルなどのリサイクルによる再利用も促進され、ボトルの分別回収が進められている。
In general, most plastic waste discarded from home is burnt or buried. In recent years, plastic products such as bottles that can be easily separated have been promoted to be reused by mechanical recycling, chemical recycling, and other recycling, and separate collection of bottles has been promoted.
しかしながら、廃棄されたプラスチックを再利用する場合、プラスチック材を材料別に分別回収しなければならない。現在のプラスチックのリサイクルによる再利用技術では、再生された製品の品質や物性を管理するため、廃棄物からできるだけ純粋なプラスチックを回収し、これを原料として再生製品を得ているため、リサイクル処理前の素材識別による分別が重要な課題となっている。
However, when recycling discarded plastic, it is necessary to separate and collect plastic materials separately. In the current recycling technology by plastic recycling, in order to control the quality and physical properties of the recycled product, as much pure plastic as possible is recovered from the waste, and the recycled product is obtained from this as a raw material. Classification by identification of materials is an important issue.
一般に、プラスチックボトルとしては、ポリエチレンテレフタレート（ＰＥＴ）、ポリスチレン（ＰＳ）、ポリプロピレン（ＰＰ）、ポリ塩化ビニル（ＰＶＣ）、及びポリエチレン（ＰＥ）が主に使用されており、近年では、前述した環境に対する優しさなどから、ポリ乳酸ボトルも提案されている。しかしながら、従来のプラスチック製品のリサイクル事業をベースとした商品の流通の中では、ポリエチレンテレフタレートとの判別が困難であることから、その分別回収についての課題が多く、実際には使用されていないのが現状である。そのため、従来のプラスチック素材の分別回収技術に加え、ポリ乳酸についての分別回収方法の開発が望まれている。
Generally, as a plastic bottle, polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP), polyvinyl chloride (PVC), and polyethylene (PE) are mainly used, and in recent years, the above-mentioned environment has been described. Polylactic acid bottles have also been proposed because of their tenderness. However, in the distribution of products based on the conventional plastic products recycling business, it is difficult to distinguish it from polyethylene terephthalate, so there are many problems with its separate collection and it is not actually used. It is the present condition. Therefore, in addition to the conventional separation and recovery technology for plastic materials, development of a separation and recovery method for polylactic acid is desired.
リサイクルに関してのプラスチック業界の技術的課題は、前記したようにポリ乳酸とＰＥＴが類似し、分別が難しいことに起因しており、つまるところ、ボトルの分別回収では、より確実に、より迅速に、ポリ乳酸とＰＥＴを識別分離回収し、且つ、他汎用樹脂、ポリスチレン（ＰＳ）、ポリプロピレン（ＰＰ）、ポリ塩化ビニル（ＰＶＣ）、及び、ポリエチレン（ＰＥ）ともポリ乳酸を識別分離することが必要である。
例えば、特許文献１～３等には、プラスチックの選別方法が提案されているが、何れの方法も、ポリ乳酸ボトルの識別分離には不満足である。 The technical challenges of the plastics industry for recycling are due to the fact that polylactic acid and PET are similar and separation is difficult as mentioned above, and finally, separate collection of bottles more reliably, faster, poly It is necessary to separate and collect lactic acid and PET, and to separate and separate polylactic acid from other general-purpose resins, polystyrene (PS), polypropylene (PP), polyvinyl chloride (PVC), and polyethylene (PE). .
For example,Patent Documents 1 to 3 and the like propose a method of sorting plastics, but none of them are unsatisfactory for identification and separation of polylactic acid bottles.
例えば、特許文献１～３等には、プラスチックの選別方法が提案されているが、何れの方法も、ポリ乳酸ボトルの識別分離には不満足である。 The technical challenges of the plastics industry for recycling are due to the fact that polylactic acid and PET are similar and separation is difficult as mentioned above, and finally, separate collection of bottles more reliably, faster, poly It is necessary to separate and collect lactic acid and PET, and to separate and separate polylactic acid from other general-purpose resins, polystyrene (PS), polypropylene (PP), polyvinyl chloride (PVC), and polyethylene (PE). .
For example,
従来のプラスチックボトル廃棄物からのプラスチック素材ごとの分別回収方法では、比重による分別や近赤外光・赤外光による光学的分別手法が用いられている。
比重による分別としては、液体サイクロンを用い、ブラスチックの比重差を利用してプラスチック素材の分類をする方法が知られている。かかる方法では、比重差による分別に先立って、機械的破砕や押圧による薄片化行程の前処理が必要である。また、比重法では、比重がほぼ同じプラスチック、例えばポリエチレン（ρ＝０．９３ｇ／ｃｍ３）とポリプロピレン（ρ＝０．９０～０．９１ｇ／ｃｍ３）とは分離が行えず、比重差の小さいプラスチック素材の識別分離が困難であった。
また、光学的分別手法は、近年になって提案されている手法であるが、機械的破砕や押圧による薄片化行程等の前処理が必要な場合が多く、このため、ボトル廃棄物から特定のプラスチックを判別して回収する際の手段としては、ほとんど検討されていない。 In the conventional method for separating and collecting plastic materials from plastic bottle waste, separation using specific gravity or optical separation using near infrared light / infrared light is used.
As separation by specific gravity, there is known a method of classifying plastic materials using a hydrocyclone and utilizing the difference in specific gravity of plastic. In such a method, it is necessary to pretreat the flaking process by mechanical crushing or pressing prior to separation by specific gravity difference. Further, the density method, the specific gravity is substantially the same plastic, such as polyethylene (ρ = 0.93g / cm 3) and not performed separation and polypropylene (ρ = 0.90 ~ 0.91g / cm 3), the difference in specific gravity Identification and separation of small plastic materials was difficult.
Also, the optical separation method is a method that has been proposed in recent years, but in many cases it is necessary to pre-treat a process such as mechanical crushing or a flaking process due to pressure. It has hardly been studied as a means for identifying and recovering plastic.
比重による分別としては、液体サイクロンを用い、ブラスチックの比重差を利用してプラスチック素材の分類をする方法が知られている。かかる方法では、比重差による分別に先立って、機械的破砕や押圧による薄片化行程の前処理が必要である。また、比重法では、比重がほぼ同じプラスチック、例えばポリエチレン（ρ＝０．９３ｇ／ｃｍ３）とポリプロピレン（ρ＝０．９０～０．９１ｇ／ｃｍ３）とは分離が行えず、比重差の小さいプラスチック素材の識別分離が困難であった。
また、光学的分別手法は、近年になって提案されている手法であるが、機械的破砕や押圧による薄片化行程等の前処理が必要な場合が多く、このため、ボトル廃棄物から特定のプラスチックを判別して回収する際の手段としては、ほとんど検討されていない。 In the conventional method for separating and collecting plastic materials from plastic bottle waste, separation using specific gravity or optical separation using near infrared light / infrared light is used.
As separation by specific gravity, there is known a method of classifying plastic materials using a hydrocyclone and utilizing the difference in specific gravity of plastic. In such a method, it is necessary to pretreat the flaking process by mechanical crushing or pressing prior to separation by specific gravity difference. Further, the density method, the specific gravity is substantially the same plastic, such as polyethylene (ρ = 0.93g / cm 3) and not performed separation and polypropylene (ρ = 0.90 ~ 0.91g / cm 3), the difference in specific gravity Identification and separation of small plastic materials was difficult.
Also, the optical separation method is a method that has been proposed in recent years, but in many cases it is necessary to pre-treat a process such as mechanical crushing or a flaking process due to pressure. It has hardly been studied as a means for identifying and recovering plastic.
一方、欧米市場では、近年、ボトル廃棄物から、素材ごとにボトルを識別分離して回収するシステムも採用されるようになってきている。このシステムでは、ボトル回収ボックスにボトル廃棄物を挿入し、回収ボックス内で、ボトルが素材ごとに分別されるのであるが、その多くが、金属、ガラス及びプラスチックを分離して回収するというものであり、プラスチックボトルの廃棄物から、プラスチック素材別に識別分離するまでには至っていない。
On the other hand, in the European and US markets, in recent years, a system has been adopted in which bottles are identified and separated for each material and separated from bottle waste. In this system, bottle waste is inserted into the bottle collection box, and the bottles are separated by material in the collection box, but many of them separate and collect metal, glass and plastic. Yes, they have not been able to identify and separate plastic material separately from plastic bottle waste.
また、プラスチックボトル廃棄物から、ボトル素材ごとに分光学的に分離回収する方法も提案されている。しかしながら、この方法においても、各種のプラスチックボトルから、ポリ乳酸ボトルを識別して分離回収する方法は検討されていない。
There is also proposed a method of spectroscopically separating and recovering each bottle material from plastic bottle waste. However, even in this method, methods for identifying, separating and recovering polylactic acid bottles from various plastic bottles have not been studied.
従って、本発明の目的は、ボトル回収ボックス等に回収されたプラスチック製ボトル廃棄物から、ポリ乳酸ボトルを識別して分別回収する方法を提供することにある。
Therefore, an object of the present invention is to provide a method for identifying and separately collecting polylactic acid bottles from plastic bottle waste collected in a bottle collection box or the like.
本発明によれば、プラスチック製ボトル廃棄物から、ポリ乳酸ボトルを分別回収する方法において、
前記プラスチックボトル廃棄物について、１６００～１８００ｎｍの波長範囲での近赤外測定を行い、１６８０ｎｍ付近に観測される短波長側吸収ピークと１７１８ｎｍ付近に観測される長波長側吸収ピークとの２つの吸収ピークを示すボトル廃棄物を、ポリ乳酸ボトルとして回収する方法が提供される。 According to the present invention, there is provided a method of separately collecting polylactic acid bottles from plastic bottle waste,
The plastic bottle waste was subjected to near-infrared measurement in the wavelength range of 1600 to 1800 nm, and two absorption peaks of the short wavelength side absorption peak observed near 1680 nm and the long wavelength side absorption peak observed near 1718 nm A method is provided for recovering peak bottle waste as polylactic acid bottles.
前記プラスチックボトル廃棄物について、１６００～１８００ｎｍの波長範囲での近赤外測定を行い、１６８０ｎｍ付近に観測される短波長側吸収ピークと１７１８ｎｍ付近に観測される長波長側吸収ピークとの２つの吸収ピークを示すボトル廃棄物を、ポリ乳酸ボトルとして回収する方法が提供される。 According to the present invention, there is provided a method of separately collecting polylactic acid bottles from plastic bottle waste,
The plastic bottle waste was subjected to near-infrared measurement in the wavelength range of 1600 to 1800 nm, and two absorption peaks of the short wavelength side absorption peak observed near 1680 nm and the long wavelength side absorption peak observed near 1718 nm A method is provided for recovering peak bottle waste as polylactic acid bottles.
本発明方法においては、
（１）ポリ乳酸ボトルの判定の根拠となる前記２つの吸収ピークについて、短波長側の吸収ピークの強度をＩＳ、を、長波長側の吸収ピークの強度をＩＬで表したとき、前記２つの吸収ピークが、下記条件式（１）及び（２）：
ＩＳ＜ＩＬ （１）
１．２≦ＩＬ／ＩＳ≦３．０ （２）
を満足していること、
が好適である。 In the method of the present invention,
(1) With regard to the two absorption peaks that are the basis of the determination of the polylactic acid bottle, when the intensity of the absorption peak on the short wavelength side is I S and the intensity of the absorption peak on the long wavelength side is I L , The two absorption peaks are represented by the following conditional expressions (1) and (2):
I S <I L (1)
1.2 ≦ I L / I S ≦ 3.0 (2)
Be satisfied,
Is preferred.
（１）ポリ乳酸ボトルの判定の根拠となる前記２つの吸収ピークについて、短波長側の吸収ピークの強度をＩＳ、を、長波長側の吸収ピークの強度をＩＬで表したとき、前記２つの吸収ピークが、下記条件式（１）及び（２）：
ＩＳ＜ＩＬ （１）
１．２≦ＩＬ／ＩＳ≦３．０ （２）
を満足していること、
が好適である。 In the method of the present invention,
(1) With regard to the two absorption peaks that are the basis of the determination of the polylactic acid bottle, when the intensity of the absorption peak on the short wavelength side is I S and the intensity of the absorption peak on the long wavelength side is I L , The two absorption peaks are represented by the following conditional expressions (1) and (2):
I S <I L (1)
1.2 ≦ I L / I S ≦ 3.0 (2)
Be satisfied,
Is preferred.
本発明方法は、ポリ乳酸の近赤外吸収に着目し、回収されたプラスチック製ボトルについて近赤外吸収スペクトルを測定して、ポリ乳酸に特有の１６８０ｎｍ付近に観測される短波長側吸収ピークと１７１８ｎｍ付近に観測される長波長側吸収ピークとの２つの吸収ピークを示すものをポリ乳酸ボトルとして識別し、他のボトルから分離して回収するものである。
即ち、２つの赤外吸収ピークを示すものをポリ乳酸ボトルと識別することにより、他の汎用プラスチック製ボトル、例えばＰＥＴボトル、ポリスチレンボトル、ポリプロピレンボトル、ポリエチレンボトル、ポリ塩化ビニルボトルなどからポリ乳酸ボトルを分離して回収することができ、これにより、ポリ乳酸の再生利用を図ることができる。 The method of the present invention focuses on the near infrared absorption of polylactic acid, measures the near infrared absorption spectrum of the recovered plastic bottle, and detects the short wavelength side absorption peak observed around 1680 nm which is characteristic of polylactic acid What shows two absorption peaks with the long wavelength side absorption peak observed near 1718 nm is identified as a polylactic acid bottle, and it separates and collects from another bottle.
That is, polylactic acid bottles from other general purpose plastic bottles, such as PET bottles, polystyrene bottles, polypropylene bottles, polyethylene bottles, polyvinyl chloride bottles, etc., are identified by identifying two infrared absorption peaks as polylactic acid bottles. Can be separated and recovered, which makes it possible to recycle polylactic acid.
即ち、２つの赤外吸収ピークを示すものをポリ乳酸ボトルと識別することにより、他の汎用プラスチック製ボトル、例えばＰＥＴボトル、ポリスチレンボトル、ポリプロピレンボトル、ポリエチレンボトル、ポリ塩化ビニルボトルなどからポリ乳酸ボトルを分離して回収することができ、これにより、ポリ乳酸の再生利用を図ることができる。 The method of the present invention focuses on the near infrared absorption of polylactic acid, measures the near infrared absorption spectrum of the recovered plastic bottle, and detects the short wavelength side absorption peak observed around 1680 nm which is characteristic of polylactic acid What shows two absorption peaks with the long wavelength side absorption peak observed near 1718 nm is identified as a polylactic acid bottle, and it separates and collects from another bottle.
That is, polylactic acid bottles from other general purpose plastic bottles, such as PET bottles, polystyrene bottles, polypropylene bottles, polyethylene bottles, polyvinyl chloride bottles, etc., are identified by identifying two infrared absorption peaks as polylactic acid bottles. Can be separated and recovered, which makes it possible to recycle polylactic acid.
本発明方法は、２つの近赤外吸収スペクトル（１６８０ｎｍ付近に観測される短波長側吸収ピークと１７１８ｎｍ付近に観測される長波長側吸収ピーク）とを示すボトルを、ポリ乳酸ボトルとして分別回収する。
即ち、図１には、各種プラスチックの近赤外領域（１６００～１８００ｎｍ）での吸収スペクトルが示されているが、この図１から理解されるように、ポリ乳酸は、１６８０ｎｍ付近に観測される短波長側吸収ピークと１７１８ｎｍ付近に観測される長波長側吸収ピークとを有する。
一方、ボトル用樹脂として汎用されている他のプラスチック、具体的には、ポリエチレンテレフタレート（ＰＥＴ）、ポリスチレン（ＰＳ）、ポリプロピレン（ＰＰ）、ポリエチレン（ＰＥ）、ポリ塩化ビニル（ＰＶＣ）についての近赤外領域での吸収ピークは、１本乃至２本の吸収ピークから形成されているが、ポリ乳酸と同じ位置に吸収ピークを有しているものはないことが図１から理解される。 The method of the present invention separates and recovers a bottle showing two near infrared absorption spectra (a short wavelength side absorption peak observed near 1680 nm and a long wavelength side absorption peak observed near 1718 nm) as a polylactic acid bottle .
That is, although the absorption spectrum in the near-infrared region (1600 to 1800 nm) of various plastics is shown in FIG. 1, as understood from this FIG. 1, polylactic acid is observed at around 1680 nm It has a short wavelength side absorption peak and a long wavelength side absorption peak observed around 1718 nm.
On the other hand, other plastics commonly used as resin for bottles, specifically, near red for polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC) It is understood from FIG. 1 that although the absorption peak in the outer region is formed of one or two absorption peaks, it has no absorption peak at the same position as that of polylactic acid.
即ち、図１には、各種プラスチックの近赤外領域（１６００～１８００ｎｍ）での吸収スペクトルが示されているが、この図１から理解されるように、ポリ乳酸は、１６８０ｎｍ付近に観測される短波長側吸収ピークと１７１８ｎｍ付近に観測される長波長側吸収ピークとを有する。
一方、ボトル用樹脂として汎用されている他のプラスチック、具体的には、ポリエチレンテレフタレート（ＰＥＴ）、ポリスチレン（ＰＳ）、ポリプロピレン（ＰＰ）、ポリエチレン（ＰＥ）、ポリ塩化ビニル（ＰＶＣ）についての近赤外領域での吸収ピークは、１本乃至２本の吸収ピークから形成されているが、ポリ乳酸と同じ位置に吸収ピークを有しているものはないことが図１から理解される。 The method of the present invention separates and recovers a bottle showing two near infrared absorption spectra (a short wavelength side absorption peak observed near 1680 nm and a long wavelength side absorption peak observed near 1718 nm) as a polylactic acid bottle .
That is, although the absorption spectrum in the near-infrared region (1600 to 1800 nm) of various plastics is shown in FIG. 1, as understood from this FIG. 1, polylactic acid is observed at around 1680 nm It has a short wavelength side absorption peak and a long wavelength side absorption peak observed around 1718 nm.
On the other hand, other plastics commonly used as resin for bottles, specifically, near red for polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC) It is understood from FIG. 1 that although the absorption peak in the outer region is formed of one or two absorption peaks, it has no absorption peak at the same position as that of polylactic acid.
また、図１の各種プラスチックについての吸収波形をみると、１６００ｎｍ～１８００ｎｍの近赤外領域の両末端波長（１６００ｎｍ及び１８００ｎｍ）において、何れのプラスチックも特有の近赤外吸収ピークが存在していない。従って、測定された近赤外吸収スペクトルを、短波長側端部（１６００ｎｍ）と長波長側端部（１８００ｎｍ）の範囲で谷－谷を直線近似することにより、ベースライン補正することができ、かかる補正により、各種プラスチックについての吸収スペクトルを明確に区別することができる。
また、上記のベースライン補正を行うことにより、ベースラインドリフト補正も自動的に行うことができ、ピークの先鋭化や、吸光度比率の演算精度が向上する。ピークの先鋭化により、近赤外測定点を多重測定し積算することで平均化処置、及び、ノイズ処理が行え、最終的な演算処理の精度をより向上させることになる。
例えば、図２～図７には、上記のようにベースライン補正及びピーク先鋭化処理された各種プラスチックの吸収スペクトルが示されているが、かかる補正により、各種プラスチックの識別を確実に行うことができ、上記の短波長側吸収ピーク（１６８０ｎｍ付近）と長波長側吸収ピーク（１７１８ｎｍ付近）のピーク存在から、ポリ乳酸ボトルを識別して分離回収することができる。 Also, looking at the absorption waveforms for various plastics in FIG. 1, no characteristic near infrared absorption peak exists in any plastic at both end wavelengths (1600 nm and 1800 nm) in the near infrared region of 1600 nm to 1800 nm. . Therefore, baseline correction can be performed by linearly approximating valley-valley in the range of the short wavelength side end (1600 nm) and the long wavelength side end (1800 nm) of the measured near infrared absorption spectrum, Such a correction makes it possible to clearly distinguish the absorption spectra for various plastics.
Further, by performing the above-described baseline correction, baseline drift correction can also be automatically performed, and peak sharpening and calculation accuracy of the absorbance ratio can be improved. By sharpening the peak, averaging processing and noise processing can be performed by multiplex measurement and integration of near infrared measurement points, and the accuracy of the final arithmetic processing will be further improved.
For example, although FIGS. 2 to 7 show absorption spectra of various plastics subjected to baseline correction and peak sharpening as described above, it is possible to reliably identify various plastics by such correction. The polylactic acid bottle can be identified, separated and recovered from the presence of the above-mentioned short wavelength side absorption peak (around 1680 nm) and long wavelength side absorption peak (around 1718 nm).
また、上記のベースライン補正を行うことにより、ベースラインドリフト補正も自動的に行うことができ、ピークの先鋭化や、吸光度比率の演算精度が向上する。ピークの先鋭化により、近赤外測定点を多重測定し積算することで平均化処置、及び、ノイズ処理が行え、最終的な演算処理の精度をより向上させることになる。
例えば、図２～図７には、上記のようにベースライン補正及びピーク先鋭化処理された各種プラスチックの吸収スペクトルが示されているが、かかる補正により、各種プラスチックの識別を確実に行うことができ、上記の短波長側吸収ピーク（１６８０ｎｍ付近）と長波長側吸収ピーク（１７１８ｎｍ付近）のピーク存在から、ポリ乳酸ボトルを識別して分離回収することができる。 Also, looking at the absorption waveforms for various plastics in FIG. 1, no characteristic near infrared absorption peak exists in any plastic at both end wavelengths (1600 nm and 1800 nm) in the near infrared region of 1600 nm to 1800 nm. . Therefore, baseline correction can be performed by linearly approximating valley-valley in the range of the short wavelength side end (1600 nm) and the long wavelength side end (1800 nm) of the measured near infrared absorption spectrum, Such a correction makes it possible to clearly distinguish the absorption spectra for various plastics.
Further, by performing the above-described baseline correction, baseline drift correction can also be automatically performed, and peak sharpening and calculation accuracy of the absorbance ratio can be improved. By sharpening the peak, averaging processing and noise processing can be performed by multiplex measurement and integration of near infrared measurement points, and the accuracy of the final arithmetic processing will be further improved.
For example, although FIGS. 2 to 7 show absorption spectra of various plastics subjected to baseline correction and peak sharpening as described above, it is possible to reliably identify various plastics by such correction. The polylactic acid bottle can be identified, separated and recovered from the presence of the above-mentioned short wavelength side absorption peak (around 1680 nm) and long wavelength side absorption peak (around 1718 nm).
また、本発明方法においては、上記のような近赤外領域での吸収スペクトルを測定したとき、前記短波長側吸収ピーク（１６８０ｎｍ付近）と長波長側吸収ピーク（１７１８ｎｍ付近）とが、下記条件式（１）及び（２）：
ＩＳ＜ＩＬ （１）
１．２≦ＩＬ／ＩＳ≦３．０ （２）
上記式中、
ＩＳは、短波長側の吸収ピークの強度であり、
ＩＬは、長波長側の吸収ピークの強度である、
を満足していることが好ましい。即ち、各種のプラスチック製ボトル廃棄物について近赤外測定を行ったとき、夾雑物等の存在により吸収スペクトルの強度がばらついたり、或いは不明確になることがある。しかるに、前述したベースライン補正やピーク先鋭化等により、吸収スペクトルを明確にすることができ、夾雑物等のないボトル廃棄物を、ポリ乳酸ボトルとして識別することができる。 Moreover, in the method of the present invention, when the absorption spectrum in the near infrared region as described above is measured, the short wavelength side absorption peak (around 1680 nm) and the long wavelength side absorption peak (around 1718 nm) Formulas (1) and (2):
I S <I L (1)
1.2 ≦ I L / I S ≦ 3.0 (2)
In the above formula,
I S is the intensity of the absorption peak on the short wavelength side,
I L is the intensity of the absorption peak on the long wavelength side,
It is preferable to satisfy That is, when near-infrared measurement is performed on various plastic bottle wastes, the intensity of the absorption spectrum may vary or be unclear due to the presence of impurities and the like. However, the absorption spectrum can be clarified by the above-described baseline correction, peak sharpening, and the like, and bottle waste free from contaminants and the like can be identified as a polylactic acid bottle.
ＩＳ＜ＩＬ （１）
１．２≦ＩＬ／ＩＳ≦３．０ （２）
上記式中、
ＩＳは、短波長側の吸収ピークの強度であり、
ＩＬは、長波長側の吸収ピークの強度である、
を満足していることが好ましい。即ち、各種のプラスチック製ボトル廃棄物について近赤外測定を行ったとき、夾雑物等の存在により吸収スペクトルの強度がばらついたり、或いは不明確になることがある。しかるに、前述したベースライン補正やピーク先鋭化等により、吸収スペクトルを明確にすることができ、夾雑物等のないボトル廃棄物を、ポリ乳酸ボトルとして識別することができる。 Moreover, in the method of the present invention, when the absorption spectrum in the near infrared region as described above is measured, the short wavelength side absorption peak (around 1680 nm) and the long wavelength side absorption peak (around 1718 nm) Formulas (1) and (2):
I S <I L (1)
1.2 ≦ I L / I S ≦ 3.0 (2)
In the above formula,
I S is the intensity of the absorption peak on the short wavelength side,
I L is the intensity of the absorption peak on the long wavelength side,
It is preferable to satisfy That is, when near-infrared measurement is performed on various plastic bottle wastes, the intensity of the absorption spectrum may vary or be unclear due to the presence of impurities and the like. However, the absorption spectrum can be clarified by the above-described baseline correction, peak sharpening, and the like, and bottle waste free from contaminants and the like can be identified as a polylactic acid bottle.
尚、本発明において、上記のようにして識別されるポリ乳酸ボトルにおいて、ボトルを形成する樹脂は、ポリ－Ｌ－乳酸、及び、光学活性異性体であるポリ－Ｄ－乳酸の何れであってもよく、例えばポリ－Ｌ－乳酸とポリ－Ｄ－乳酸との混合物であってもよい。通常、ボトルを形成する樹脂の９５質量％以上がポリ－Ｌ－乳酸及び／またはポリ－Ｄ－乳酸である限りにおいて、他の樹脂がブレンドされている場合においても、上記の２つの吸収ピークにより、ポリ乳酸ボトルと判定される。
In the present invention, in the polylactic acid bottle identified as described above, the resin forming the bottle is either poly-L-lactic acid or poly-D-lactic acid which is an optically active isomer. It may also be, for example, a mixture of poly-L-lactic acid and poly-D-lactic acid. Usually, as long as 95% by mass or more of the resin forming the bottle is poly-L-lactic acid and / or poly-D-lactic acid, even if other resins are blended, the above two absorption peaks , Poly lactic acid bottle is determined.
尚、ボトル廃棄物について近赤外測定を行うとき、通常、ボトルは肉厚であることなどから、透過法測定では観測ピークがサチュレーションを生じる場合があり、演算処理の元データーとして適用できない場合もありうる。又、ボトルのラベルなどによるスペクトル形状の変化から観測スペクトルが演算に適していない場合もありうる。そのため、反射法による測定手法が好適に採用される。
In addition, when performing near-infrared measurement on bottle waste, the observation peak may cause saturation in transmission method measurement because the thickness of the bottle is usually large, etc., and it may not be applied as the original data of the arithmetic processing. It is possible. Also, there are cases where the observed spectrum is not suitable for calculation due to the change of the spectrum shape due to the label of the bottle or the like. Therefore, the measurement method by the reflection method is suitably adopted.
また、実際のボトル分別回収装置では、３５０ｍＬ～２Ｌのサイズの異なるボトルの素材の識別分離を行うため、投入ボトルのサイズに合わせ、近赤外光源と集光光学系（受光系）の位置を自動的に調整する機構が付いていることが好ましい。
一例としては、ボトル投入口から投入されたボトルが、ボトルを静置させるために設けた傾斜面にそって静置させ、底位置基準で口部までの距離をＣＣＤカメラで観測後、近赤光の照射光位置と集光光学系の位置を自動設定する方法が適用される。ボトル底部と口部間の距離から算出される、肩部、底部に選択的に近赤外光を照射、集光（受光）するように光学系を連動作動させる方法であり、近赤外光源から発生した近赤外光を反射鏡で該当位置に調整する方法などが適用される。 Also, in an actual bottle sorting and collecting apparatus, the positions of the near infrared light source and the condensing optical system (light receiving system) are adjusted according to the size of the input bottle in order to identify and separate the material of bottles different in size from 350 mL to 2 L. It is preferable to have a mechanism for adjusting automatically.
As an example, a bottle inserted from a bottle insertion port is allowed to stand along an inclined surface provided for allowing the bottle to stand, and after observing the distance to the mouth with a CCD camera based on the bottom position reference, near red A method of automatically setting the position of the light irradiation light and the position of the focusing optical system is applied. A method of interlocking the optical system to selectively emit near infrared light and collect (receive) near infrared light on the shoulder and bottom calculated from the distance between the bottle bottom and the mouth The method of adjusting the near-infrared light which generate | occur | produced from to the applicable position with a reflective mirror etc. is applied.
一例としては、ボトル投入口から投入されたボトルが、ボトルを静置させるために設けた傾斜面にそって静置させ、底位置基準で口部までの距離をＣＣＤカメラで観測後、近赤光の照射光位置と集光光学系の位置を自動設定する方法が適用される。ボトル底部と口部間の距離から算出される、肩部、底部に選択的に近赤外光を照射、集光（受光）するように光学系を連動作動させる方法であり、近赤外光源から発生した近赤外光を反射鏡で該当位置に調整する方法などが適用される。 Also, in an actual bottle sorting and collecting apparatus, the positions of the near infrared light source and the condensing optical system (light receiving system) are adjusted according to the size of the input bottle in order to identify and separate the material of bottles different in size from 350 mL to 2 L. It is preferable to have a mechanism for adjusting automatically.
As an example, a bottle inserted from a bottle insertion port is allowed to stand along an inclined surface provided for allowing the bottle to stand, and after observing the distance to the mouth with a CCD camera based on the bottom position reference, near red A method of automatically setting the position of the light irradiation light and the position of the focusing optical system is applied. A method of interlocking the optical system to selectively emit near infrared light and collect (receive) near infrared light on the shoulder and bottom calculated from the distance between the bottle bottom and the mouth The method of adjusting the near-infrared light which generate | occur | produced from to the applicable position with a reflective mirror etc. is applied.
近赤外によるプラスチック素材の識別装置は、ハロゲンランプを用いた近赤外光源と、集光光学系で集光された近赤外光をＰｂｓ及びＩｎＧａＡｓ（インジウムガリウム素子）からなる受光素子（検出器）で検出する検出器から構成され、検出信号は、増幅器とＡ／Ｄ変換（アナログ／デジタル変換）を通して信号強度の増幅とデジタル変換後、パーソナルコンピュターで演算処理され、材料識別が行われる。
A device for identifying plastic materials based on near-infrared light includes a near-infrared light source using a halogen lamp, and a light-receiving element (detection from Pbs and InGaAs (indium gallium element) near infrared light condensed by a condensing optical system) The detection signal is amplified and digitally converted by an amplifier and A / D conversion (analog / digital conversion), and then processed by a personal computer to perform material identification.
例えば、近赤外光スペクトルを１６００ｎｍ～１８００ｎｍ波長領域で２００ポイント～２００００ポイントのデーター点として観測し、空間分解能１．０ｎｍ～０．０１ｎｍの測定後、Ａ／Ｄ変化処理、１次微分で変曲点を算出する。（２ポイント（２本のピーク成分を）識別するアルゴリズムを用い、少なくとも２本のピークを観測するが、１ポイント（１本のピーク）しか観測されない場合は１ポイントと認識とする。）１６００ｎｍのピーク強度と１８００ｎｍのピーク強度を直線補正し、ベースライン補正後、ピーク強度が最大のピークについて、ピーク強度を１とする規格化処理を行い、ノイズ除去とピーク先鋭化処理を行うことが好適である。
For example, the near-infrared light spectrum is observed as data points of 200 points to 20000 points in the wavelength range of 1600 nm to 1800 nm, and after measurement of spatial resolution 1.0 nm to 0.01 nm, A / D change processing changes by first derivative. Calculate the curve point. (At least two peaks are observed using an algorithm that identifies two points (two peak components), but if only one point (one peak) is observed, it is recognized as one point.) 1600 nm The peak intensity and the peak intensity at 1,800 nm are linearly corrected, and after baseline correction, it is preferable to perform normalization processing with the peak intensity at 1 for the peak with the largest peak intensity, and perform noise removal and peak sharpening processing is there.
例えば１６８０ｎｍと１７１８ｎｍの２つのピークが観測された場合は、ポリ乳酸素材として素材識別し、ポリ乳酸ボトル専用の回収箱に回収する。
For example, when two peaks at 1680 nm and 1718 nm are observed, the material is identified as a polylactic acid material, and collected in a collection box dedicated to polylactic acid bottles.
Ａ／Ｄ変換後の変量（ｘ・ｙ）データーは、ｘが波長（ｎｍ）・ｙが強度（Ｉ：強度）を示すデーターであり、１次微分の変曲点をピークトップとして求めたピークの中心波長（ｎｍ）の前後２ポイント分を残し、残りのピーク成分を０に規格化処理するが、この場合、１次微分で変曲点でないピーク成分に関しては、ピーク認識せず、０規格化の対象とすることで、ピーク成分のみをスティックスペクトルに変換（二値化）することができる。このようにして得られた、一番強いピーク成分と２番目の第２ピーク成分の２変量値（ｘ、ｙ）を用い、吸光度比の演算を行うことができる。
The variable (x, y) data after A / D conversion is data in which x indicates the wavelength (nm) and y indicates the intensity (I: intensity), and the peak determined with the inflection point of the first derivative as the peak top The remaining peak components are normalized to 0, leaving two points before and after the center wavelength (nm) of the peak wavelength. In this case, no peak is recognized for peak components not at the inflection point in the first derivative, and 0 standard By making it a target of conversion, only peak components can be converted (binarized) into a stick spectrum. The absorbance ratio can be calculated using the bivariate values (x, y) of the strongest peak component and the second peak component obtained as described above.
１６８０ｎｍと１７１８ｎｍの２つのピーク成分が観測された（認識された）ポリ乳酸ボトルについては、１６８０ｎｍと１７１８ｎｍそれぞれのピークの強度から、吸光度比の算出を行い、これにより、前述した条件式（１）及び（２）を満足しているか否かを判定することができる。
この場合、計算に用いるアルゴリズムは、長波長側ピーク成分の強度を短波長側ピーク成分の強度で除するように設定することで、吸光度比（ＩＬ／ＩＳ）を算出することができる。即ち、ポリ乳酸の場合、吸光度比（ＩＬ／ＩＳ）が１．２～３．０の範囲になり、この吸光度比の数値範囲から、ポリ乳酸ボトルを、より正確に識別分離し回収することができる。 With regard to the polylactic acid bottle in which two peak components of 1680 nm and 1718 nm were observed (recognized), the absorbance ratio is calculated from the intensities of the peaks at 1680 nm and 1718 nm, respectively, and thereby the conditional expression (1) described above It can be determined whether or not (2) is satisfied.
In this case, the algorithm used for the calculation can calculate the absorbance ratio (I L / I S ) by setting the intensity of the long wavelength side peak component to be divided by the intensity of the short wavelength side peak component. That is, in the case of polylactic acid, the absorbance ratio (I L / I S ) is in the range of 1.2 to 3.0, and polylactic acid bottles are more accurately identified and separated and recovered from the numerical value range of this absorbance ratio. be able to.
この場合、計算に用いるアルゴリズムは、長波長側ピーク成分の強度を短波長側ピーク成分の強度で除するように設定することで、吸光度比（ＩＬ／ＩＳ）を算出することができる。即ち、ポリ乳酸の場合、吸光度比（ＩＬ／ＩＳ）が１．２～３．０の範囲になり、この吸光度比の数値範囲から、ポリ乳酸ボトルを、より正確に識別分離し回収することができる。 With regard to the polylactic acid bottle in which two peak components of 1680 nm and 1718 nm were observed (recognized), the absorbance ratio is calculated from the intensities of the peaks at 1680 nm and 1718 nm, respectively, and thereby the conditional expression (1) described above It can be determined whether or not (2) is satisfied.
In this case, the algorithm used for the calculation can calculate the absorbance ratio (I L / I S ) by setting the intensity of the long wavelength side peak component to be divided by the intensity of the short wavelength side peak component. That is, in the case of polylactic acid, the absorbance ratio (I L / I S ) is in the range of 1.2 to 3.0, and polylactic acid bottles are more accurately identified and separated and recovered from the numerical value range of this absorbance ratio. be able to.
また、図１に示されている様に、１６００ｎｍ～１８００ｎｍ波長領域の近赤外スペクトルでは、ポリピロピレン（ＰＰ）やポリ塩化ビニル（ＰＶＣ）では、互いに近接したダブルピークが観測されるが、ポリプロピレン（ＰＰ）の場合は、１７０２ｎｍ（短波長側ピーク）と１７２２ｎｍ（長波長側ピーク）位置に特性吸収ピークが観測され、１７００ｎｍより短波長側にはピークがないため、ポリ乳酸との識別が容易に行える。また、長波長側ピーク強度を短波長側ピーク強度で除した吸光度比（ＩＬ／ＩＳ）は、１．１以下となることから、吸光度比の値からも、ポリプロピレン（ＰＰ）とポリ乳酸ボトルを容易に識別分別して回収することができる。
In addition, as shown in FIG. 1, in the near infrared spectrum in the wavelength range of 1600 nm to 1800 nm, double peaks close to each other are observed in polypyropyrene (PP) and polyvinyl chloride (PVC). In the case of PP), characteristic absorption peaks are observed at 1702 nm (short wavelength side peak) and 1722 nm (long wavelength side peak), and there is no peak at less than 1700 nm, so identification with polylactic acid is easy. It can do. Further, since the absorbance ratio (I L / I S ) obtained by dividing the long wavelength side peak intensity by the short wavelength side peak intensity is 1.1 or less, polypropylene (PP) and polylactic acid are also obtained from the value of the absorbance ratio. Bottles can be easily identified and separated and collected.
同様に、塩化ビニル（ＰＶＣ）も１７１０ｎｍと１７４５ｎｍに特性吸収ピークが観測されるが、吸収波長によるポリ乳酸との識別が行うと同時に、吸光度比（ＩＬ／ＩＳ）が＝０．８となり、ポリ乳酸ボトルとより正確に識別分離できることになる。又、ポリエチレン（ＰＥ）も１７２４ｎｍと１７６０ｎｍに特性吸収ピークが観測されるが、吸収波長によるポリ乳酸との識別を行うと同時に、吸光度比（ＩＬ／ＩＳ）が＝０．３５となり、ポリ乳酸ボトルとより正確に識別分離できることになる。
Similarly, characteristic absorption peaks are also observed at 1710 nm and 1745 nm for vinyl chloride (PVC), but the absorbance ratio (I L / I S ) is equal to 0.8 at the same time as discrimination with polylactic acid is performed by the absorption wavelength. , Can be more accurately identified and separated from the polylactic acid bottle. In addition, polyethylene (PE) also shows characteristic absorption peaks at 1724 nm and 1760 nm, but at the same time it discriminates from polylactic acid by the absorption wavelength, the absorbance ratio (I L / I S ) becomes 0.35, and poly It will be able to distinguish and separate more accurately from lactic acid bottles.
前述した手法で規格化された近赤外スペクトルの変量値は、分光学測定とその演算で問題となるベースラインのうねりやドリフトが改善され、数値解析が容易にできる利点があるほか、ラベル物や残留内容物などの供雑成分由来のピークとの分離が行え、ボトル識別の分離回収精度が向上する。また、吸光度比を用いたプラスチック素材の識別分離する場合においても、算出値そのもの精度が向上することから、より精度の高いボトル素材の識別分離システムとして用いることができるようになる。
The variable values of the near-infrared spectrum standardized by the above-mentioned method have the advantage of improving baseline waviness and drift, which are a problem in spectroscopy measurement and calculation thereof, and facilitating numerical analysis, and label objects And separation of peaks derived from contamination components such as residual contents, and the separation and collection accuracy of bottle identification is improved. In addition, even in the case of identifying and separating plastic materials using the absorbance ratio, since the accuracy of the calculated value itself is improved, it can be used as a system for identifying and separating bottle materials with higher accuracy.
さらに、上記方法で求めたスティックスペクトルが１６５５ｎｍで規格化された１本のピークであれば、ポリエチレンテレフタレートボトル（ＰＥＴ）として専用の回収箱に回収される。また、スティックスペクトルが１６８２ｎｍで規格化された１本のピークであれば、ポリスチレン（ＰＳ）ボトルとして専用の回収箱に回収される。
Furthermore, if the stick spectrum obtained by the above method is one peak standardized at 1655 nm, it is collected as a polyethylene terephthalate bottle (PET) in a dedicated collection box. In addition, if the stick spectrum is one peak standardized at 1682 nm, it is collected as a polystyrene (PS) bottle in a dedicated collection box.
本発明の優れた効果を次の実験例で説明する。なお、実験例の内容に限定されるものではない。
The excellent effects of the present invention will be described in the following experimental examples. In addition, it is not limited to the content of an experiment example.
実験に用いた各ボトルとしては、以下のものを使用した。
ポリ乳酸ボトルＡ：
重量平均分子量（ＭＷ）がＭＷ＝２００，０００で、且つ、光学活性異性体（ｄ）比率が１．５％のポリ－Ｌ－乳酸（ＰＬＬＡ）樹脂製のボトル。
ポリ乳酸ボトルＢ：
重量平均分子量（ＭＷ）がＭＷ＝２５０，０００で、且つ、光学活性異性体（ｄ）比率が９９．０％のポリ－Ｄ－乳酸（ＰＤＬＡ）樹脂。
他のプラスチックボトルＣ：
ポリ乳酸以外のボトルはサイズの近い市販品ボトルを使用。
内容物を廃棄後、軽く水洗して用いた。 The following were used as each bottle used for experiment.
Polylactic acid bottle A:
A bottle made of poly-L-lactic acid (PLLA) resin having a weight-average molecular weight (MW) of MW = 200,000 and an optically active isomer (d) ratio of 1.5%.
Polylactic acid bottle B:
Poly-D-lactic acid (PDLA) resin having a weight average molecular weight (MW) of MW = 250,000 and an optically active isomer (d) ratio of 99.0%.
Other plastic bottles C:
Bottles other than polylactic acid use commercially available bottles of similar size.
After discarding the contents, it was lightly rinsed and used.
ポリ乳酸ボトルＡ：
重量平均分子量（ＭＷ）がＭＷ＝２００，０００で、且つ、光学活性異性体（ｄ）比率が１．５％のポリ－Ｌ－乳酸（ＰＬＬＡ）樹脂製のボトル。
ポリ乳酸ボトルＢ：
重量平均分子量（ＭＷ）がＭＷ＝２５０，０００で、且つ、光学活性異性体（ｄ）比率が９９．０％のポリ－Ｄ－乳酸（ＰＤＬＡ）樹脂。
他のプラスチックボトルＣ：
ポリ乳酸以外のボトルはサイズの近い市販品ボトルを使用。
内容物を廃棄後、軽く水洗して用いた。 The following were used as each bottle used for experiment.
Polylactic acid bottle A:
A bottle made of poly-L-lactic acid (PLLA) resin having a weight-average molecular weight (MW) of MW = 200,000 and an optically active isomer (d) ratio of 1.5%.
Polylactic acid bottle B:
Poly-D-lactic acid (PDLA) resin having a weight average molecular weight (MW) of MW = 250,000 and an optically active isomer (d) ratio of 99.0%.
Other plastic bottles C:
Bottles other than polylactic acid use commercially available bottles of similar size.
After discarding the contents, it was lightly rinsed and used.
ポリ乳酸ボトルの作製
上記のポリ乳酸（ＰＬＬＡ或いはＰＤＬＡ）を、射出成形機において１９０℃～２４０℃の温度条件下、金型温度１５℃のプリフォーム金型に射出成形し、口径３５ｍｍφのプリフォームを作成した。
次いで、プリフォームを赤外線ヒーターで９０℃に再加熱後、金型温度８５℃のブロー金型で５００ｍｌ容積のボトルにブロー成形し、上記のポリ乳酸ボトルＡ，Ｂを得た。 Preparation of Polylactic Acid Bottle The above polylactic acid (PLLA or PDLA) was injection molded into a preform mold having a mold temperature of 15 ° C. in an injection molding machine at a temperature of 190 ° C. to 240 ° C. It was created.
Then, the preform was reheated to 90 ° C. with an infrared heater and blow molded into a 500 ml volume bottle with a blow mold having a mold temperature of 85 ° C. to obtain the above polylactic acid bottles A and B.
上記のポリ乳酸（ＰＬＬＡ或いはＰＤＬＡ）を、射出成形機において１９０℃～２４０℃の温度条件下、金型温度１５℃のプリフォーム金型に射出成形し、口径３５ｍｍφのプリフォームを作成した。
次いで、プリフォームを赤外線ヒーターで９０℃に再加熱後、金型温度８５℃のブロー金型で５００ｍｌ容積のボトルにブロー成形し、上記のポリ乳酸ボトルＡ，Ｂを得た。 Preparation of Polylactic Acid Bottle The above polylactic acid (PLLA or PDLA) was injection molded into a preform mold having a mold temperature of 15 ° C. in an injection molding machine at a temperature of 190 ° C. to 240 ° C. It was created.
Then, the preform was reheated to 90 ° C. with an infrared heater and blow molded into a 500 ml volume bottle with a blow mold having a mold temperature of 85 ° C. to obtain the above polylactic acid bottles A and B.
（近赤外測定とボトル分別装置）
ボトルが静置できる斜面の暗室部位に隣接し、ハロゲンランプを用いた近赤外光源と、集光光学系で集光された近赤外光をＩｎＧａＡｓ（インジウムガリウム素子）からなる受光素子（検出器）で検出するボトル回収箱を作成した。検出信号を、増幅器とＡ／Ｄ変換（アナログ／デジタル変換）を通してデジタル変換後、パーソナルコンピュターで演算処理した。 (Near infrared measurement and bottle sorter)
A light receiving element (detecting a near infrared light source using a halogen lamp and a near infrared light collected by a light collection optical system adjacent to a dark room part of a slope where the bottle can be placed) made of InGaAs (indium gallium element) Container collection box to be detected by The detection signal was subjected to digital processing through an amplifier and A / D conversion (analog / digital conversion) and then processed by a personal computer.
ボトルが静置できる斜面の暗室部位に隣接し、ハロゲンランプを用いた近赤外光源と、集光光学系で集光された近赤外光をＩｎＧａＡｓ（インジウムガリウム素子）からなる受光素子（検出器）で検出するボトル回収箱を作成した。検出信号を、増幅器とＡ／Ｄ変換（アナログ／デジタル変換）を通してデジタル変換後、パーソナルコンピュターで演算処理した。 (Near infrared measurement and bottle sorter)
A light receiving element (detecting a near infrared light source using a halogen lamp and a near infrared light collected by a light collection optical system adjacent to a dark room part of a slope where the bottle can be placed) made of InGaAs (indium gallium element) Container collection box to be detected by The detection signal was subjected to digital processing through an amplifier and A / D conversion (analog / digital conversion) and then processed by a personal computer.
光源及び受光器は、ボトルの肩部と底部の２カ所を中心に、前後に２カ所、計６箇所の任意部位に設置した。測定は２０回積算し、得られた検出信号は増幅回路、Ａ／Ｄ変換装置を経過後、パソコンに信号を伝達させ、平均化処理・ベースラインコレクト・演算を行い、ポリ乳酸ボトルに検出できた場合、複数に仕切られた回収箱のポリ乳酸専用箱にエアー排出させた。回収箱は、ポリ乳酸（ＰＬＬＡ）とポリエチレンテレフタレート（ＰＥＴ）、ポリ塩化ビニル（ＰＶＣ）、ポリスチレン（ＰＳ）及びポリプロピレン（ＰＰ）、ポリエチレン（ＰＥ）の六個の回収箱を準備した。
The light source and the light receiver were installed at six arbitrary positions in total, two at the front and back, centering on the bottle at the shoulder and the bottom. The measurement is integrated 20 times, and the detection signal obtained can be detected in the polylactic acid bottle by transmitting the signal to the personal computer after passing through the amplifier circuit and A / D converter, performing averaging processing, baseline correction, calculation. In this case, the air was discharged into a polylactic acid-only box of a collection box divided into a plurality of parts. The collection box prepared six collection boxes of polylactic acid (PLLA) and polyethylene terephthalate (PET), polyvinyl chloride (PVC), polystyrene (PS) and polypropylene (PP), and polyethylene (PE).
（評価）
分離精度を確認するため、ポリ乳酸ボトルとポリ乳酸ボトル以外のボトルを組み合わせ、順不同に２０本連続に、ボトル識別分離回収ボックスに投入、分別した。
回収ボックスに分別されたボトルと回収ボックスの関係を確認した。それぞれの素材がそれぞれの指定回収ボックスに１００％分離された場合は◎、ポリ乳酸ボトルのみポリ乳酸ボトル回収ボックスに１００％分離されていた場合は○、ポリ乳酸ボトルが他の回収箱に回収された場合は×とした。 (Evaluation)
In order to confirm the separation accuracy, a polylactic acid bottle and a bottle other than the polylactic acid bottle were combined, and 20 bottles in order were put into the bottle identification separation and recovery box and sorted in random order.
The relationship between the bottles separated in the collection box and the collection box was confirmed. If each material is separated 100% in each designated collection box ボ ッ ク ス, if only polylactic acid bottle is separated 100% in polylactic acid bottle collection box ○, polylactic acid bottle collected in another collection box In the case of failure, it was marked as x.
分離精度を確認するため、ポリ乳酸ボトルとポリ乳酸ボトル以外のボトルを組み合わせ、順不同に２０本連続に、ボトル識別分離回収ボックスに投入、分別した。
回収ボックスに分別されたボトルと回収ボックスの関係を確認した。それぞれの素材がそれぞれの指定回収ボックスに１００％分離された場合は◎、ポリ乳酸ボトルのみポリ乳酸ボトル回収ボックスに１００％分離されていた場合は○、ポリ乳酸ボトルが他の回収箱に回収された場合は×とした。 (Evaluation)
In order to confirm the separation accuracy, a polylactic acid bottle and a bottle other than the polylactic acid bottle were combined, and 20 bottles in order were put into the bottle identification separation and recovery box and sorted in random order.
The relationship between the bottles separated in the collection box and the collection box was confirmed. If each material is separated 100% in each designated collection box ボ ッ ク ス, if only polylactic acid bottle is separated 100% in polylactic acid bottle collection box ○, polylactic acid bottle collected in another collection box In the case of failure, it was marked as x.
＜実験例１＞
ポリ乳酸ボトルＡ（ＰＬＬＡ）を５本、ポリエチレンテレフタレート（ＰＥＴ）ボトル３本、ポリ塩化ビニル（ＰＶＣ）ボトル３本、ポリスチレン（ＰＳ）ボトル３本、ポリプロピレン（ＰＰ）ボトル３本、ポリエチレン（ＰＥ）ボトル３本（合計２０本）をランダムにボトル分別回収ボックスの近赤外測定室に投入した。この場合、Ａ／Ｄ変換後のスペクトル情報を用い、観測波長の認識にて識別分離回収した。結果を表１に示した。 Experimental Example 1
Five polylactic acid bottles A (PLLA), three polyethylene terephthalate (PET) bottles, three polyvinyl chloride (PVC) bottles, three polystyrene (PS) bottles, three polypropylene (PP) bottles, polyethylene (PE) Three bottles (total 20 bottles) were randomly placed in the near-infrared measurement chamber of the bottle separation and collection box. In this case, the spectrum information after A / D conversion was used to identify, separate, and collect the observed wavelength. The results are shown in Table 1.
ポリ乳酸ボトルＡ（ＰＬＬＡ）を５本、ポリエチレンテレフタレート（ＰＥＴ）ボトル３本、ポリ塩化ビニル（ＰＶＣ）ボトル３本、ポリスチレン（ＰＳ）ボトル３本、ポリプロピレン（ＰＰ）ボトル３本、ポリエチレン（ＰＥ）ボトル３本（合計２０本）をランダムにボトル分別回収ボックスの近赤外測定室に投入した。この場合、Ａ／Ｄ変換後のスペクトル情報を用い、観測波長の認識にて識別分離回収した。結果を表１に示した。 Experimental Example 1
Five polylactic acid bottles A (PLLA), three polyethylene terephthalate (PET) bottles, three polyvinyl chloride (PVC) bottles, three polystyrene (PS) bottles, three polypropylene (PP) bottles, polyethylene (PE) Three bottles (total 20 bottles) were randomly placed in the near-infrared measurement chamber of the bottle separation and collection box. In this case, the spectrum information after A / D conversion was used to identify, separate, and collect the observed wavelength. The results are shown in Table 1.
＜実験例２＞
ポリ乳酸ボトルＢ（ＰＤＬＡ）を５本、ＰＥＴボトル３本、ＰＶＣボトル３本、ＰＳボトル３本、ＰＰボトル３本、ＰＥボトル３本（合計２０本）をランダムにボトル分別回収ボックスの近赤外測定室に投入した。この場合、Ａ／Ｄ変換後のスペクトル情報を用い、観測波長の認識にて識別分離回収した。結果を表１に示した <Experimental Example 2>
Five polylactic acid bottles B (PDLA), three PET bottles, three PVC bottles, three PS bottles, three PP bottles, three PE bottles (total 20 bottles) Randomly colored bottles near the red separation box It was introduced into the outside measurement room. In this case, the spectrum information after A / D conversion was used to identify, separate, and collect the observed wavelength. The results are shown in Table 1
ポリ乳酸ボトルＢ（ＰＤＬＡ）を５本、ＰＥＴボトル３本、ＰＶＣボトル３本、ＰＳボトル３本、ＰＰボトル３本、ＰＥボトル３本（合計２０本）をランダムにボトル分別回収ボックスの近赤外測定室に投入した。この場合、Ａ／Ｄ変換後のスペクトル情報を用い、観測波長の認識にて識別分離回収した。結果を表１に示した <Experimental Example 2>
Five polylactic acid bottles B (PDLA), three PET bottles, three PVC bottles, three PS bottles, three PP bottles, three PE bottles (total 20 bottles) Randomly colored bottles near the red separation box It was introduced into the outside measurement room. In this case, the spectrum information after A / D conversion was used to identify, separate, and collect the observed wavelength. The results are shown in Table 1
＜実験例３＞
ポリ乳酸ボトルＡを５本、ＰＥＴボトル３本、ＰＶＣボトル３本、ＰＳボトル３本、ＰＰボトル３本、ＰＥボトル３本（合計２０本）をランダムにボトル分別回収ボックスの近赤外測定室に投入した。この場合、Ａ／Ｄ変換後のスペクトル情報を用い、１６８０ｎｍと１７１８ｎｍの２つの成分が観測された（識別された）ボトルであり、且つ、長波長ピーク成分強度と短波長ピーク成分強度のピーク強度比（吸光度比ＩＬ／ＩＳ）の演算値を行い、観測波長の認識と吸光度比による多変量解析にて識別した。結果を表１に示した。 <Experimental Example 3>
Near-infrared measurement room of the bottle separation and collection box at random: 5 polylactic acid bottles A, 3 PET bottles, 3 PVC bottles, 3 PS bottles, 3 PP bottles, 3 PE bottles (20 total) Put in the In this case, it is a bottle in which two components of 1680 nm and 1718 nm are observed (identified) using spectrum information after A / D conversion, and peak intensities of long wavelength peak component intensity and short wavelength peak component intensity Arithmetic values of the ratio (absorbance ratio I L / I S ) were calculated, and recognition was performed using the observation wavelength and multivariate analysis using the absorbance ratio. The results are shown in Table 1.
ポリ乳酸ボトルＡを５本、ＰＥＴボトル３本、ＰＶＣボトル３本、ＰＳボトル３本、ＰＰボトル３本、ＰＥボトル３本（合計２０本）をランダムにボトル分別回収ボックスの近赤外測定室に投入した。この場合、Ａ／Ｄ変換後のスペクトル情報を用い、１６８０ｎｍと１７１８ｎｍの２つの成分が観測された（識別された）ボトルであり、且つ、長波長ピーク成分強度と短波長ピーク成分強度のピーク強度比（吸光度比ＩＬ／ＩＳ）の演算値を行い、観測波長の認識と吸光度比による多変量解析にて識別した。結果を表１に示した。 <Experimental Example 3>
Near-infrared measurement room of the bottle separation and collection box at random: 5 polylactic acid bottles A, 3 PET bottles, 3 PVC bottles, 3 PS bottles, 3 PP bottles, 3 PE bottles (20 total) Put in the In this case, it is a bottle in which two components of 1680 nm and 1718 nm are observed (identified) using spectrum information after A / D conversion, and peak intensities of long wavelength peak component intensity and short wavelength peak component intensity Arithmetic values of the ratio (absorbance ratio I L / I S ) were calculated, and recognition was performed using the observation wavelength and multivariate analysis using the absorbance ratio. The results are shown in Table 1.
＜実験例４＞
ポリ乳酸ボトルＡを５本、ＰＥＴボトル３本、ＰＶＣボトル３本、ＰＳボトル３本、ＰＰボトル３本、ＰＥボトル３本（合計２０本）をランダムにボトル分別回収ボックスの近赤外測定室に投入した。この場合、Ａ／Ｄ変換後のスペクトル情報を用い、ポリ乳酸（ＰＬＬＡ）の近赤外の観測波長、１６８０ｎｍと１７１８ｎｍの波長情報を除き、ＰＥＴ、ＰＶＣ、ＰＳ、ＰＰ及びＰＥの波長情報を用いた分離回収試験を行った。結果を表１に示した。 <Experimental Example 4>
Near-infrared measurement room of the bottle separation and collection box at random: 5 polylactic acid bottles A, 3 PET bottles, 3 PVC bottles, 3 PS bottles, 3 PP bottles, 3 PE bottles (20 total) Put in the In this case, the spectrum information after A / D conversion is used, and the wavelength information of PET, PVC, PS, PP and PE is used except for the wavelength information of 1680 nm and 1718 nm of near infrared observation wavelength of polylactic acid (PLLA). The separation and recovery test was conducted. The results are shown in Table 1.
ポリ乳酸ボトルＡを５本、ＰＥＴボトル３本、ＰＶＣボトル３本、ＰＳボトル３本、ＰＰボトル３本、ＰＥボトル３本（合計２０本）をランダムにボトル分別回収ボックスの近赤外測定室に投入した。この場合、Ａ／Ｄ変換後のスペクトル情報を用い、ポリ乳酸（ＰＬＬＡ）の近赤外の観測波長、１６８０ｎｍと１７１８ｎｍの波長情報を除き、ＰＥＴ、ＰＶＣ、ＰＳ、ＰＰ及びＰＥの波長情報を用いた分離回収試験を行った。結果を表１に示した。 <Experimental Example 4>
Near-infrared measurement room of the bottle separation and collection box at random: 5 polylactic acid bottles A, 3 PET bottles, 3 PVC bottles, 3 PS bottles, 3 PP bottles, 3 PE bottles (20 total) Put in the In this case, the spectrum information after A / D conversion is used, and the wavelength information of PET, PVC, PS, PP and PE is used except for the wavelength information of 1680 nm and 1718 nm of near infrared observation wavelength of polylactic acid (PLLA). The separation and recovery test was conducted. The results are shown in Table 1.
従来から提案されてきた近赤外波長による素材の識別分析法ではポリ乳酸ボトルの波長解析が行われておらず、また、波長識別による識別分離法のみでは分離回収の精度が不十分であった。原因は正確に完全に究明できていないが、残留内容物やラベル由来のノイズが関係しているものと推察されている。これら従来法に比べ、本発明によれば、所定の近赤外領域での２つのポリ乳酸に特有の吸収ピークを利用して、種々のプラスチックボトル廃棄物から、ポリ乳酸ボトルを精度よく、分別回収することができ、ポリ乳酸、さらには他の樹脂についても、そのリサイクルを有効に行うことができる。
Wavelength analysis of polylactic acid bottles has not been performed by the material discrimination analysis method based on the near infrared wavelength, which has been proposed conventionally, and the accuracy of separation and recovery is insufficient only by the discrimination method by wavelength discrimination . Although the cause has not been completely elucidated completely, it is presumed that residual content and noise derived from the label are related. Compared to these conventional methods, according to the present invention, polylactic acid bottles are accurately separated from various plastic bottle wastes by using absorption peaks specific to two polylactic acids in a predetermined near infrared region It can be recovered, and recycling of polylactic acid and other resins can be effectively performed.
Claims (2)
- プラスチック製ボトル廃棄物から、ポリ乳酸ボトルを分別回収する方法において、
前記プラスチックボトル廃棄物について、１６００～１８００ｎｍの波長範囲での近赤外測定を行い、１６８０ｎｍ付近に観測される短波長側吸収ピークと１７１８ｎｍ付近に観測される長波長側吸収ピークとの２つの吸収ピークを示すボトル廃棄物を、ポリ乳酸ボトルとして回収する方法。 In a method of separately collecting polylactic acid bottles from plastic bottle waste,
The plastic bottle waste was subjected to near-infrared measurement in the wavelength range of 1600 to 1800 nm, and two absorption peaks of the short wavelength side absorption peak observed near 1680 nm and the long wavelength side absorption peak observed near 1718 nm A method of collecting bottle waste that shows peaks as polylactic acid bottles. - ポリ乳酸ボトルの判定の根拠となる前記２つの吸収ピークについて、短波長側の吸収ピークの強度をＩＳ、を、長波長側の吸収ピークの強度をＩＬで表したとき、前記２つの吸収ピークが、下記条件式（１）及び（２）：
ＩＳ＜ＩＬ （１）
１．２≦ＩＬ／ＩＳ≦３．０ （２）
を満足している請求項１に記載の方法。 When the intensity of the absorption peak on the short wavelength side is I S , and the intensity of the absorption peak on the long wavelength side is I L , of the two absorption peaks that are the basis of the determination of the polylactic acid bottle, the two absorptions The peaks have the following conditional expressions (1) and (2):
I S <I L (1)
1.2 ≦ I L / I S ≦ 3.0 (2)
The method according to claim 1, which is satisfied.
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| Publication number | Publication date |
|---|---|
| TW201922362A (en) | 2019-06-16 |
| JP2019078678A (en) | 2019-05-23 |
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