Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D1/00—Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/02—Separating plastics from other materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/04—Disintegrating plastics, e.g. by milling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D1/00—Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
  • B65D1/02—Bottles or similar containers with necks or like restricted apertures, designed for pouring contents
  • B65D1/0207—Bottles or similar containers with necks or like restricted apertures, designed for pouring contents characterised by material, e.g. composition, physical features
  • B65D1/0215—Bottles or similar containers with necks or like restricted apertures, designed for pouring contents characterised by material, e.g. composition, physical features multilayered
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D7/00—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D7/00—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal
  • B65D7/02—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal characterised by shape
  • B65D7/04—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal characterised by shape of curved cross-section, e.g. cans of circular or elliptical cross-section
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
  • C08J11/04—Recovery or working-up of waste materials of polymers
  • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
  • C08J11/14—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with steam or water
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/02—Separating plastics from other materials
  • B29B2017/0213—Specific separating techniques
  • B29B2017/0286—Cleaning means used for separation
  • B29B2017/0289—Washing the materials in liquids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/02—Separating plastics from other materials
  • B29B2017/0213—Specific separating techniques
  • B29B2017/0293—Dissolving the materials in gases or liquids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/04—Disintegrating plastics, e.g. by milling
  • B29B2017/0424—Specific disintegrating techniques; devices therefor
  • B29B2017/0436—Immersion baths
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2003/00—Use of starch or derivatives as moulding material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
  • B29K2067/04—Polyesters derived from hydroxycarboxylic acids
  • B29K2067/043—PGA, i.e. polyglycolic acid or polyglycolide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
  • B29K2067/04—Polyesters derived from hydroxycarboxylic acids
  • B29K2067/046—PLA, i.e. polylactic acid or polylactide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2667/00—Use of polyesters or derivatives thereof for preformed parts, e.g. for inserts
  • B29K2667/04—Polyesters derived from hydroxycarboxylic acids
  • B29K2667/043—PGA, i.e. polyglycolic acid or polyglycolide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2031/00—Other particular articles
  • B29L2031/712—Containers; Packaging elements or accessories, Packages
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2031/00—Other particular articles
  • B29L2031/712—Containers; Packaging elements or accessories, Packages
  • B29L2031/7158—Bottles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/40—Properties of the layers or laminate having particular optical properties
  • B32B2307/402—Coloured
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2439/00—Containers; Receptacles
  • B32B2439/40—Closed containers
  • B32B2439/60—Bottles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D2565/00—Wrappers or flexible covers; Packaging materials of special type or form
  • B65D2565/38—Packaging materials of special type or form
  • B65D2565/381—Details of packaging materials of special type or form
  • B65D2565/385—Details of packaging materials of special type or form especially suited for or with means facilitating recycling
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
  • C08J2367/04—Polyesters derived from hydroxy carboxylic acids, e.g. lactones
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/582—Recycling of unreacted starting or intermediate materials
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/62—Plastics recycling; Rubber recycling
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]

Definitions

• the present invention relates to a bottle with excellent recyclability comprising a glycolic acid polymer layer in addition to a principal resin layer and also to a recycling method therefor.
• the term “bottle” refers not only to a bottle in its narrow or ordinary sense having a small size of mouth or neck relative to its internal volume but also refers to a (hollow) shaped container in general for containing contents material therein. It is believed readily understandable from the following description that the effect of the present invention is not restricted by a strict shape of containers.
• Resin-made bottles are used widely and in large masses as containers for various liquid materials, such as drinking water, seasonings, edible oil, alcoholic beverages, fuels, and detergents, because of their lightness, transparency allowing seeing therethrough of the content materials, etc.
• PET bottles made of polyester resins, especially bottles made of PET (polyethylene terephthalate).
• bottles are required to suppress the transmission therethrough of carbon dioxide gas or oxygen gas for improving the preservability of contents therein.
• a multiple layer structure of providing a gas barrier coating or disposing a gas barrier resin layer as an intermediate layer e.g., a multiple layer structure of providing a gas barrier coating or disposing a gas barrier resin layer as an intermediate layer.
• An object of the present invention is to provide a bottle which has a laminate structure including an additional resin layer in addition to a principal resin layer and is yet provided with excellent recyclability, and also an efficient method of recycling the bottle.
• the bottle excellent in recyclability according to the present invention is characterized by having a laminate structure including at least one layer of glycolic acid polymer in addition to a principal resin layer.
• the bottle recycling method according to the present invention is characterized by comprising the steps of: breaking a bottle having a laminate structure including at least one layer of glycolic acid polymer in addition to a principal resin layer, and washing broken pieces of the bottle with alkaline water, water or acidic water to remove the glycolic acid polymer layer, thereby recovering the principal resin.
• glycolic acid polymer is particularly excellent as a resin constituting an additional resin layer of a bottle to be recycled are as follows.
• Glycolic acid polymer has an extremely high gas-barrier property as high as ca. 3 times or higher (i.e., ca. 1 ⁇ 3 or lower in terms of an oxygen transmission coefficient) as that of EVOH (ethylene-vinyl alcohol copolymer) which is a representative gas-barrier resin used heretofore, so that a bottle with a remarkably improved gas-barrier property can be obtained by including a thin layer thereof in addition to the principal resin layer. Accordingly, it becomes possible to effectively prevent the degradation of contents due to oxidation or poorer quality due to dissipation of carbon dioxide gas.
• EVOH ethylene-vinyl alcohol copolymer
• glycolic acid polymer used in the present invention has a substantial hydrolyzability with alkaline washing liquid, water (particularly, warmed water) or acid water, so that it can be easily separated by washing from the principal resin material to be recovered.
• glycolic acid formed by hydrolyzation of the glycolic acid polymer in the washing waste liquid can be biologically decomposed into carbon dioxide gas and water by subjecting the washing waste liquid to neutralization and treatment with activated sludge, thus being obviated from functioning as a load to the environment.
• polylactic acid-based polymer which is a conventionally known representative biodegradable resin does not exhibit gas-barrier property like that of glycolic acid polymer, and can only show a slower hydrolyzation speed with alkaline water, water or acidic water.
• Glycolic acid polymer is a hydrolyzable polyester having a recurring unit represented by a formula (1) below: —(OCH 2 CO)— (1)
• glycolic acid homopolymer consisting only of the above recurring unit, but another recurring unit can be contained provided that a structure having a main chain which can be cut by hydrolysis is preferred.
• Preferable structures may include ester structures including carboxylic acid esters and carbonic acid esters, and amide structure. Particularly, an aliphatic ester structure is preferred because of easiness of hydrolysis. Examples thereof may include the following: —(OCHCH 3 CO)— (2) —(OCH 2 CH 2 CH 2 OCO)— (3) —(OCH 2 CH 2 CH 2 CO)— (4)
• the proportion of such another recurring unit structure is below 50 wt. %, preferably below 30 wt.
• glycolic acid polymer it is possible to incorporate a thermal stabilizer, a plasticizer, etc., as may be required for melt-processing, and further a colorant, such as a pigment, within an extent not adverse to the object of the present invention.
• thermoplastic resins As a principal resin forming the bottle together with a layer of the glycolic acid polymer, various species and grades of thermoplastic resins may be used, inclusive of polyesters as represented by PET (i.e., polyethylene terephthalate) and polyethylene naphthalate (PEN); polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polycarbonate (PC), polystyrene (PS) and polylactic acid (PLA).
• PET i.e., polyethylene terephthalate
• PEN polyethylene naphthalate
• PVC polyvinyl chloride
• PE polyethylene
• PP polypropylene
• PC polycarbonate
• PS polystyrene
• PLA polylactic acid
• glycolic acid polymer has a remarkably higher gas-barrier property than these general-purpose resins, and can form a bottle with an improved gas-barrier property in case of being laminated with any of these resins.
• PET as a principal resin for the bottle from the view point of economy and also energy consumption for the recovery and recycling. It is preferred to use PET having an inherent viscosity in the range of 0.5-1.5 dl/g, particularly 0.6-1.2 dl/g.
• glycolic acid polymer is contained in the principal resin layer, but the content thereof should preferably be at most 10 wt. %, further preferably at most 3 wt. %, most preferably at most 1 wt. %.
• a principal resin layer containing glycolic acid polymer is generally found in the case where the principal resin layer is formed of a recycled resin layer comprising the principal resin and glycolic acid polymer, etc. Accordingly, in this case, the amount of the glycolic acid polymer can depend on the level of gas-barrier property required of the bottle of the present invention. If a resin material substantially free from glycolic acid polymer is desired to be recovered, it is preferred to use a principal resin free from glycolic acid polymer.
• the glycolic acid polymer layer is preferably formed as an intermediate layer sandwiched between an outer layer and an inner layer composed as principal resin layers forming the bottle.
• the intermediate layer may be formed in a single layer or plural layers.
• the formation ratio between the inner and outer layer resin and the glycolic acid polymer may be arbitrarily determined depending on a performance and a quality desired of the bottle.
• the weight ratio (substantially corresponding to a layer thickness ratio) between the principal resin and the glycolic acid polymer is preferably in the range of 99/1-55/45, particularly 98/2-80/20.
• the glycolic acid polymer layer is formed in a thickness of at least 3 ⁇ m so as to exhibit a good gas-barrier property.
• the thickness should preferably be retained in the body or trunk portion which occupies a major area of a bottle and, in some cases, the glycolic acid polymer layer can be not present at the bottom or neck portion.
• a recovery resin layer comprising a mixture of the principal resin and the glycolic acid polymer and in such a case, the content of glycolic acid polymer in the recovery resin layer should preferably be at most 50 wt. %, further preferably at most 30 wt. %, most preferably at most 10 wt. %.
• examples of the laminate layer structure in the case of including a recovery resin layer may include: principal resin/recovery resin/glycolic acid polymer/principal resin, principal resin/glycolic acid polymer/recovery resin, etc.
• an adhesive resin as desired, e.g., between the principal resin layer and the glycolic acid polymer layer, but it is preferred not to insert such a layer if it obstructs the recyclability.
• Bottle recycling has been actually performed with respect to PET bottles.
• PET bottles are broken or cut, washed with alkaline water and recovered as PET resin.
• the bottles of the present invention are recycled through recycling steps similar to those in the above-mentioned PET bottle recycling system.
• the separation of glycolic acid polymer can also be made by utilizing a difference in specific gravity, but the utilization of washing with alkaline water, water or acid is more efficient and reliable.
• the alkaline water washing may be performed, e.g., by using 0.01-5 normal of alkaline water washing liquid at 20-100° C., preferably 40-98° C., for 5 min.-10 hours, and can efficiently hydrolyze the glycolic acid polymer in a short time into glycolic acid.
• the water washing may be performed by using water at an elevated temperature of at least 40° C. (and optionally under pressure) so as to accelerate the hydrolysis.
• Acidic water also has an effect of accelerating the glycolic acid polymer similarly as alkaline water and is used at 20-100° C. preferably 40-98° C.
• As the acid glycolic acid per se is preferred.
• the washing may be performed at one time or plural times.
• the adhesion strength between a glycolic acid polymer layer and a PET layer is not so strong, and partial peeling therebetween may frequently occur during the bottle breaking step. This is also a factor of accelerating the removal by dissolution of the glycolic acid polymer during the washing with alkaline water, water or acidic water.
• the washing waste liquid formed by washing with alkaline water, etc., containing glycolic acid resulting from hydrolysis of the glycolic acid polymer can possibly be discharged as it is after neutralization as glycolic acid is an organic acid occurring in nature but may preferably be subjected to activated sludge treatment to biologically decompose glycolic acid into. H 2 O and CO 2 , thereby alleviating the load to the ecological system.
• the activated sludge treatment is a step also contained in the conventional PET bottle recycling system, and the bottle recycling method according to the present invention can be practiced without new equipment investment and only with a slight increase in the load of the activated sludge treatment.
• the aqueous washing liquid containing glycolic acid produced by hydrolysis may be recycled to be used as washing water having an effect of accelerating hydrolysis of the glycolic acid polymer to form a condensed glycolic acid aqueous solution (of which the concentration is suitably at most 70%), which is then further condensed and polycondensed to be recovered as glycolic acid oligomer.
• the glycolic acid oligomer may be converted into glycolide (cyclic dimer ester of glycolic acid) useful as a starting material for polyglycolic according to a process disclosed in International Publication WO-A 02/14303. More specifically, the process of WO-A 02/14303 allows a process including the steps of:
• the glycolic acid polymer layer is colored.
• a colored bottle is obtained and can suppress photodegradation, etc., of the content material by controlling the transmission of light rays.
• the glycolic acid polymer layer may be uniformly colored but an arbitrary pattern of colored layer can be disposed thereover to provide an increased aesthetic design effect.
• the colorant may be selected from any known ones to develop a desired color but, in view of load to the environment after the recycling, it is preferred to use a biodegradable dye or pigment, e.g., edible red dye for coloring in red.
• Another advantage accompanying the coloring of the glycolic acid polymer layer is that it allows the determination of the condition, such as the number and time, of washing for the recycling through eye observation. More specifically, the remaining of glycolic acid polymer results in the remaining of solid colored resin, thus allowing easy judgment of incomplete separation of the glycolic acid polymer. As a result, the quality control of the recovered principal resin after the recycling can be remarkably simplified.
• a colored bottle with a colored intermediate layer may be applied to intermediate layer resins other than glycolic acid polymer, but this is not practical since it does not provide a sufficient function (such as gas-barrier property) other than an improved design effect by the coloring.
• a sufficient function such as gas-barrier property
• the presence of a colored resin layer has made difficult the separation of the resins for the recycling to provide an obstacle factor in the recycling, but this is utterly contrary in case of the bottom of the present invention.
• the thus-formed bottle was cut into 2 cm-square pieces and washed for 5 hours in a 1 normal-caustic soda aqueous solution at 80° C.
• the washed pieces were filtered out, washed with water and dried to obtain 36 g of recovered resin.
• the thus-recovered resin was analyzed with respect to infrared absorption spectrum whereby absorption peaks attributable to only PET were observed, thereby confirming complete removal of PGA.
• a bottle was prepared in the same manner as in Example 1 except that PGA colored with 0.1 part of carbon black per 100 wt. parts thereof was used.
• the thus-formed bottle were cut into 2 cm-square pieces and washed for 5 hours in a 1 normal-caustic soda aqueous solution at 80° C.
• the washed pieces were filtered out, washed with water and dried to obtain colorless recovered resin.
• the thus-recovered resin was analyzed with respect to infrared absorption spectrum whereby absorption peaks attributable to only PET were observed, thereby confirming complete removal of carbon black and PGA.
• a bottle prepared in the same manner as in Example 2 was cut into 2 cm-square pieces, which were then washed for 3 min. in a 1 normal-caustic soda aqueous solution at 80° C.
• the washed pieces were filtered out but some black-colored solid remained on the pieces.
• the pieces were again washed for further 3 hours in a 1 normal-caustic soda aqueous solution at 80° C.
• Example 2 The PET resin recovered in Example 2 was melt-pressed at 270° C. and cooled by a cooling press at room temperature to obtain a colorless transparent PET sheet. As a result, it was confirmed that the recovered resin was formable and the principal resin PET could be recycled.
• the alkaline aqueous solution after the washing in Example 1 was analyzed by liquid chromatography, whereby glycolic acid was detected.
• the solution was neutralized, diluted with 100 times of water and fed to activated sludge matured by aeration, followed by culturing in an aerobic environment at room temperature for 1 month. After the one month, the reaction liquid was again analyzed by liquid chromatography, whereby no glycolic acid was detected at all.
• the reaction liquid was further analyzed with respect to dissolved organic carbon by a total organic carbon meter (“TOC-5000A”, made by Shimadzu Seisakusho K.K.), whereby no organic carbon was detected, and the reaction liquid was discharged as it was.
• TOC-5000A made by Shimadzu Seisakusho K.K.
• a bottle which has a laminate structure including a glycolic acid polymer layer showing good gas-barrier property in addition to a principal resin layer and is yet provided with excellent recyclability, and also an efficient method of recycling the bottle.

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• Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
• Processing Of Solid Wastes (AREA)
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• Laminated Bodies (AREA)
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• 2003
  • 2003-05-16 US US10/514,048 patent/US20050175801A1/en not_active Abandoned
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• 2008
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