Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
  • C08L77/06—Polyamides derived from polyamines and polycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/42—Polyamides containing atoms other than carbon, hydrogen, oxygen, and nitrogen
• • 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
• • 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
• • 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
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
  • C08J3/09—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids
  • C08J3/11—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids from solid polymers
• • 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
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/12—Powdering or granulating
  • C08J3/14—Powdering or granulating by precipitation from solutions
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/60—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyamides
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
  • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
  • D01F8/12—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyamide as constituent
• • 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
  • B29B17/0005—Direct recuperation and re-use of scrap material during moulding operation, i.e. feed-back of used 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
  • B29B2017/001—Pretreating the materials before recovery
  • B29B2017/0021—Dividing in large parts
• • 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
  • B29B2017/0203—Separating plastics from plastics
• • 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
  • 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
  • B29K2077/00—Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, 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
  • B29K2083/00—Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material
• • 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
  • B29L2022/00—Hollow articles
  • B29L2022/02—Inflatable articles
  • B29L2022/027—Air bags
• • 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
  • C08J2300/00—Characterised by the use of unspecified polymers
  • C08J2300/30—Polymeric waste or recycled polymer
• • 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
  • C08J2377/00—Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers
  • C08J2377/06—Polyamides derived from polyamines and polycarboxylic acids
• • 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
  • C08J2483/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
  • C08J2483/04—Polysiloxanes
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2331/00—Fibres made from polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polycondensation products
  • D10B2331/02—Fibres made from polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polycondensation products polyamides
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2401/00—Physical properties
  • D10B2401/06—Load-responsive characteristics
  • D10B2401/063—Load-responsive characteristics high strength
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2505/00—Industrial
  • D10B2505/12—Vehicles
  • D10B2505/124—Air bags
• • 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

Definitions

• the present invention relates to a polyamide composition that is less likely to clog during melt processing and can therefore prevent clogging of processing equipment over long periods of time, as well as a method for producing the same, and to fibers, woven fabrics, and airbags.
• Polyamides including polyamide 6 and polyamide 66, are representative engineering plastics that have excellent heat resistance and mechanical properties and are widely used in textiles, automotive parts, electrical appliance parts, and more. They are one of the irreplaceable materials in modern society. Among these, polyamide 66 is extremely important, as it is used in applications that require heat resistance and durability in particularly harsh environments.
• Recycling can be broadly divided into material recycling, which re-pelletizes molded products, and chemical recycling, which reuses monomers through depolymerization.
• Material recycling raises concerns that the quality of the polymers contained in the molded products may not be stable because the polymer degradation and additives remain in the recycled polymer.
• material recycling is chosen when recycling is intended for a fixed purpose, since it does not involve chemical reactions and requires fewer auxiliary materials, and therefore requires fewer resources and energy.
• additives and coatings are removed from processed and used polyamides collected from factories and markets before chemical recycling, a process of recovering clean polyamide is carried out in the same way as material recycling, so material recycling technology is also useful for chemical recycling.
• polyamides have a wide range of applications, but one of the applications of polyamide 66 is automotive applications, which require high safety. For example, it is used in engine parts that require high heat resistance and in airbag base fabrics that require durability when bursting. Among them, airbag base fabrics are least likely to deteriorate and are suitable for material recycling. Not only used airbags, but also scraps generated when cutting parts during the manufacture and sewing of airbag base fabrics can be recycled.
• the base fabric of an airbag is made by spinning and weaving polyamide 66 into a woven fabric, which is then coated with silicone resin. Therefore, in order to material recycle the airbag base fabric, it is necessary to separate this coating from the polyamide 66.
• Patent Document 1 As a physical method for removing impurities from polyamide containing impurities to make it in a clean state, there is a method of crushing the recovered material and then separating it by specific gravity (Patent Document 1). Although this method can separate the impurities with little energy, it is difficult to separate the impurities from the polyamide in the case of an airbag base fabric in which the polyamide and the impurities are strongly bound together by mixing, joining, adhesion, etc. There is also a method of dissolving or removing all or a part of unnecessary impurities such as silicone with a solvent (for example, Patent Document 2). The recovered polyamide is recovered in the form of crushed cloth. Used airbags and scraps from manufacturing have various shapes, and it is difficult to reuse them as they are or in the form of fiber waste obtained by cutting them, so they need to be melted and pelletized.
• Patent Document 4 describes a method in which a silicone-coated polyamide cloth is treated with a methanol solution of calcium chloride to dissolve the polyamide, and the polyamide is diluted with a large amount of water or methanol to obtain the desired polyamide as a powder.
• the object of the present invention is to provide a polyamide composition that is less likely to clog the flow paths of filters and other equipment during melt processing such as melt spinning, and that allows the equipment to operate continuously for long periods of time. Furthermore, the present invention preferably provides a polyamide yarn that suppresses weaving bar defects in the base fabric without restricting the production deadline for the yarn.
• silicone resin mixed into the polyamide.
• silicone resin When silicone resin coats a polyamide base fabric, it penetrates into the fibers of the base fabric and hardens. Therefore, even if you try to peel off the silicone, the silicone resin that remains inside the polyamide fibers will remain in the regenerated polyamide.
• the polyamide recovery method using a calcium chloride methanol solution the polyamide is dissolved, which reduces the amount of silicone resin remaining inside the polyamide fibers.
• the coated silicone resin is thin and fine, some of the silicone resin is finely chopped by the stirring blades, etc., and is mixed in.
• the present invention is as follows.
• [1] A polyamide composition containing a silicon compound, the polyamide composition having a silicon atom content of 1000 ppm or less as determined by X-ray fluorescence analysis.
• [3a] The recycled polyamide composition according to any one of [1] to [3], which is in the form of a powder.
• [3b] The recycled polyamide composition according to any one of [1] to [3a], which is for use in fibers.
• polyamide composition according to any one of [1] to [5], wherein the polyamide comprises polyamide 66.
• a method for producing a polyamide composition comprising a step of dissolving polyamide from a silicone-coated polyamide base fabric, the step being carried out using a vessel having a mechanism for preventing contact between a part rotated by an external power source and the silicone-coated polyamide base fabric during dissolution.
• [7a] A method for producing a polyamide composition according to any one of [1] to [6], comprising a step of dissolving polyamide from a silicone-coated polyamide base fabric, the step being carried out using a vessel having a mechanism for preventing contact between a part rotated by an external power source and the silicone-coated polyamide base fabric during dissolution.
• [7b] A method for producing a recycled polyamide composition according to any one of [1] to [6], comprising a step of dissolving polyamide from a silicone-coated polyamide base fabric, the step being carried out using a vessel having a mechanism for continuously recovering the silicone resin generated during dissolution.
• the method comprises the steps of: placing a polyamide-containing material containing a polyamide and a component insoluble in a metal chloride alcohol solution in a container having a liquid passage hole made of an insoluble resin; adding the metal chloride alcohol solution containing a metal chloride and an alcohol; stirring at 120° C. or less to dissolve the polyamide; and separating the insoluble component in the container.
• a method for producing a polyamide solution comprising: [20] The method according to [19], wherein the insoluble resin is at least one of polyethylene, polypropylene, polyurethane, polystyrene, polydimethylsiloxane, and polyester.
• the present invention provides a recycled polyamide composition that is less likely to clog filters during melt spinning and allows for long-term continuous operation. It also provides polyamide fibers that can improve the quality of airbag base fabrics.
• the present invention relates to a polyamide composition which is less likely to clog flow paths such as filters in a processing device during melt processing such as melt spinning, and which enables the processing device to be operated continuously for long periods of time, and a method for producing the same.
• polyamide refers to a polymer polymerized through amide bonds, such as a polycondensation product of a diamine compound and a dicarboxylic acid compound, or a ring-opening polymerization product of a cyclic lactam.
• Diamine compounds are not particularly limited, but examples include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, nonanediamine, methylpentanediamine, and p-phenylenediamine.
• Dicarboxylic acid compounds are not particularly limited, but examples include oxalic acid, glutaric acid, adipic acid, sebacic acid, terephthalic acid, and isophthalic acid.
• Cyclic lactams include, but are not limited to, ⁇ -caprolactam, undecane lactam, lauryllactam, etc.
• the combination of diamine compounds, dicarboxylic acid compounds and cyclic lactam compounds is not particularly limited, and multiple types of each type may be used in combination.
• the polyamide is not particularly limited, but examples include those containing aliphatic polyamides such as polyamide 66, polyamide 6, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 46, polyamide 6T, polyamide 6I, copolymers thereof and mixtures thereof, with those containing aliphatic polyamides being preferred and those containing polyamide 66 being most preferred.
• Those containing polyamide 66 are melt spinnable, have a high melting point, excellent heat resistance, are highly flexible, have a not too high water absorption rate and are easy to handle.
• the polyamide composition of the present invention contains a silicon compound.
• silicon compounds include organosilicon compounds used to coat polyamides. In other words, they include fine particles of silicone resin itself and organically treated silica, which is a filler and reinforcing material for silicone resin.
• the method for quantifying the silicon compounds contained in the polyamide composition is preferably X-ray fluorescence analysis, which can analyze both inorganic and organic silicon compounds. There are no specific analytical conditions, and it is sufficient to use conditions that can correctly quantify the amount of trace impurities contained in the polyamide composition.
• the amount of silicon compounds contained in the polyamide composition is 1000 ppm or less, preferably 700 ppm or less, and more preferably 500 ppm or less, as the silicon atom content quantified by X-ray fluorescence analysis. If the amount of silicon compounds is large, clogging occurs easily and continuous operation cannot be performed. Also, it is preferable that the amount is 30 ppm or more.
• the fiber loses plasticity and its stretchability is impaired, but if the silicon atoms are contained in an amount of 30 ppm or more, uniform stretching is performed with the silicon compounds as the fulcrum during fiber production, and the decrease in stretchability due to the decrease in low oligomer components can be compensated for.
• the elements not derived from silicon or polyamide contained in the polyamide composition of the present invention include, but are not limited to, calcium and zinc (e.g., in the form of calcium compounds and zinc compounds).
• the amount of calcium contained in the polyamide composition is preferably 1000 ppm or less, more preferably 700 ppm or less, and even more preferably 500 ppm or less, as the calcium atom content quantified by X-ray fluorescence analysis.
• the amount of zinc contained in the polyamide composition is preferably 1000 ppm or less, more preferably 700 ppm or less, and even more preferably 500 ppm or less, as the zinc atom content quantified by X-ray fluorescence analysis.
• the content of polyamide components (hereinafter sometimes referred to as "oligomers") having a degree of polymerization of 5 or less in the polyamide composition is preferably 10,000 ppm or less, more preferably 5,000 ppm or less, even more preferably 2,500 ppm or less, and even more preferably 2,000 ppm or less, as determined by GPC analysis.
• the degree of polymerization in this embodiment refers to the number of minimum repeating unit structures constituting the polyamide, and the unit structures may be repeated in a linear or cyclic manner. If there are many polyamide components having a degree of polymerization of 5 or less, the mechanical strength during molding decreases, so it is preferable that the content of polyamide components having a degree of polymerization of 5 or less in the polyamide composition is small.
• the method for evaluating the coloration of a polyamide composition is not particularly limited, but the Yellowness Index (hereinafter referred to as YI, ASTM E313) can be used based on the coloration tendency. If the coloration is light and close to white, the Whiteness Index (hereinafter referred to as WI, CIE Whiteness) can also be used.
• YI Yellowness Index
• WI CIE Whiteness
• the coloration of a polyamide composition is preferably 20 or less, more preferably 17 or less, and most preferably 13 or less.
• WI CIE Whiteness
• the shape of the polyamide composition is not particularly limited, and examples include polyamide melted and pelletized during production (e.g., regeneration), or polyamide dissolved in a solvent and then precipitated into a powder.
• the amount of polyamide components with a degree of polymerization of 5 or less in the polyamide fiber of this embodiment is 20,000 ppm or less, preferably 10,000 ppm or less, and more preferably 5,000 ppm or less. If the amount of polyamide components with a degree of polymerization of 5 or less in the fiber is 20,000 ppm or less, the mobility of the molecules can be suppressed in the low to normal temperature range, and the 3-month shrinkage reduction rate of the raw yarn described below can be suppressed. Although the amount of polyamide components with a degree of polymerization of 5 or less in the polyamide fiber increases by melt spinning the polyamide composition, the shrinkage rate of the fiber increases over time because the amount is 20,000 ppm or less.
• the amount of polyamide components with a degree of polymerization of 5 or less is 100 ppm or more in absolute value due to the unavoidable increase due to the influence of heat during melting.
• the amount of silicon compound contained in the polyamide fiber of this embodiment is 30 ppm to 1000 ppm, preferably 50 ppm to 700 ppm, more preferably 100 ppm to 500 ppm, as the silicon atom content quantified by X-ray fluorescence analysis.
• the silicon compound contains 30 ppm or more of silicon atoms, uniform stretching is performed with the silicon compound as the fulcrum, and the decrease in stretchability due to the decrease in low oligomer components can be compensated for.
• the content of the silicon compound is 1000 ppm or less of silicon atoms, spinning clogging is unlikely to occur and continuous operation is possible.
• the silicon compound is basically derived from the organic silicon compound used to coat polyamide products.
• silicone resin itself or organically treated silica, which is a filling and reinforcing material for silicone resin, and while it is compatible with polyamide, it acts as a stretching fulcrum that is thinly and evenly dispersed as an extremely fine solid, improving stretchability.
• the polyamide fiber of this embodiment preferably has no peak in tan ⁇ in the -50°C to +50°C range in dynamic viscoelasticity measurement.
• the value of tan ⁇ in the -50°C to +50°C range in dynamic viscoelasticity measurement is 0.05 or less.
• tan ⁇ has a peak in the +90°C to +130°C range, and the tan ⁇ peak value is preferably 0.100 to 0.150, more preferably 0.105 to 0.140, and even more preferably 0.110 to 0.130.
• Dynamic viscoelasticity measurement can be performed by the method described in the Examples below.
• the polyamide fiber of the present embodiment has the following physical properties (1) to (7): (1) a total fineness of 150 dtex or more and 2500 dtex or less; (2) Strength of 6.0 cN/dtex or more and 11.0 cN/dtex or less; (3) Elongation of 15% or more and 30% or less; (4) boiling water shrinkage of 4.0% or more and 11.0% or less; (5) a finish deposition rate of 0.5% by weight or more and 1.5% by weight or less; (6) 30 to 400 single yarns; (7) 3-month shrinkage decline of 12% or less; It is preferable that the yarn is a multifilament yarn having the following structure:
• the total fineness of the polyamide fibers of this embodiment is preferably 150 dtex or more, more preferably 175 dtex or more, and even more preferably 200 dtex or more, from the viewpoint of sufficient mechanical properties when used in airbags and airbag base fabrics.
• the total fineness of the polyamide fibers is preferably 2500 dtex or less, more preferably 1500 dtex or less, and even more preferably 1000 dtex or less.
• the tensile strength of the polyamide fiber of this embodiment is preferably 6.0 cN/dtex or more, more preferably 7.0 cN/dtex or more, even more preferably 8.0 cN/dtex or more, and preferably 11.0 cN/dtex or less, more preferably 10.0 cN/dtex or less, and even more preferably 9.0 cN/dtex or less. If the tensile strength is equal to or greater than the lower limit, the tensile strength is excellent and sufficient mechanical properties for airbag applications are obtained. On the other hand, if the tensile strength is equal to or less than the upper limit, production is possible without a significant decrease in process stability due to an increase in fuzz or thread breakage.
• the elongation of the polyamide fiber of this embodiment is preferably 15% or more, more preferably 16% or more, even more preferably 17% or more, and preferably 30% or less, more preferably 28% or less, and even more preferably 25% or less. If the elongation is equal to or greater than the lower limit, sufficient toughness (strength index) for airbag applications can be obtained. Furthermore, there is a trade-off between elongation and strength, and in order to achieve a balance with strength, it is preferable that the elongation be equal to or less than the upper limit.
• the boiling water shrinkage rate of the polyamide fiber of this embodiment is preferably 4.0% or more, more preferably 5.0% or more, even more preferably 6.0% or more, preferably 11.0% or less, more preferably 10.0% or less, and even more preferably 9.0% or less. If the boiling water shrinkage rate is equal to or higher than the lower limit, the fabric can be shrunk in the processing step after weaving, which contributes to making the finished fabric denser. On the other hand, taking into consideration other characteristics and production costs, etc., it is preferable that the boiling water shrinkage rate is substantially equal to or lower than the upper limit.
• the number of single threads of the polyamide fiber in this embodiment is preferably 30 or more, more preferably 50 or more, even more preferably 70 or more, and preferably 400 or less, more preferably 300 or less, and even more preferably 200 or less.
• the number of single threads of the multifilament yarn be equal to or greater than the above lower limit, the specific surface area increases and the fabric can flexibly respond to external stress, improving the breathability and tear resistance of the base fabric.
• the number of single threads of the multifilament yarn be equal to or less than the above upper limit, fusion of the single threads to each other during melt spinning can be avoided.
• the three-month shrinkage reduction rate of the polyamide fiber of this embodiment is preferably 12% or less. More preferably, it is 11% or less, and even more preferably, it is 10% or less.
• the three-month shrinkage reduction rate refers to the value obtained by measuring the rate of change in boiling water shrinkage rate over time after the product is wound up, comparing it immediately after winding with that after three months of storage.
• the total fineness, strength, elongation, boiling water shrinkage rate, finishing agent adhesion rate, and 3-month shrinkage reduction rate can be measured, for example, by the method described in the Examples.
• the polyamide fiber of this embodiment also has excellent yarn breakage suppression during spinning (yarn breakage resistance). Yarn breakage resistance can be evaluated, for example, by the method described in the examples.
• the polyamide examples of the polyamide fiber of this embodiment are the same as the polyamide examples exemplified as the "polyamide composition".
• the polyamide fiber of this embodiment may be, for example, polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 46, polyamide 6T, polyamide 6I, copolymers thereof, and mixtures thereof.
• polyamide 66 fiber mainly made of polyhexamethylene adipamide fiber is preferred.
• Polyhexamethylene adipamide refers to polyamide fiber composed of 100% hexamethylene diamine and adipic acid and having a melting point of 250°C or higher.
• the polyamide 66 fiber of the present invention may be a fiber made of a polymer obtained by copolymerizing or blending polyhexamethylene adipamide with polyamide 8, polyamide 6I, polyamide 10, polyamide 6T, etc., as long as the melting point is not less than 250°C.
• the spinning temperature in melt spinning is preferably 290° C. or higher and 310° C. or lower. Setting the spinning temperature to 310° C. or lower is preferable because thermal decomposition of the polyamide can be suppressed, more preferably 300° C. or lower, and even more preferably 295° C. or lower. On the other hand, a spinning temperature of 290° C. or higher is preferable because the polyamide exhibits sufficient melt fluidity, the discharge amount between the discharge holes is uniform, and high-magnification drawing is possible.
• the residence time is preferably 30 minutes or less, more preferably 15 minutes or less, and even more preferably 0.5 to 7 minutes.
• a short residence time is preferable because the amount of polyamide components with a degree of polymerization of 5 or less in the polymer increases at the melting temperature.
• a copper compound for thermal stability in high temperature and high humidity environments, it is preferable to add a copper compound to the polyamide so that the copper concentration is 1 to 500 ppm, and more preferably 30 to 500 ppm.
• the copper concentration is 1 to 500 ppm, and more preferably 30 to 500 ppm.
• the copper compound is not particularly limited in type, and for example, an organic copper salt such as copper acetate, or a copper halide such as cuprous chloride or cupric chloride can be preferably used.
• the copper compound is more preferably used in combination with a metal halide compound.
• the metal halide compound include potassium iodide, potassium bromide, and potassium chloride.
• the preferred combinations are cuprous iodide and potassium iodide, and copper acetate and potassium iodide.
• the copper content in the polyamide can be measured by atomic absorption spectrometry, colorimetry, or the like.
• Stabilizers that may be added include, but are not limited to, organic antioxidants such as hindered phenol antioxidants, sulfur antioxidants, and phosphorus antioxidants, heat stabilizers, light stabilizers such as hindered amines, benzophenones, and imidazoles, and ultraviolet absorbers.
• organic antioxidants such as hindered phenol antioxidants, sulfur antioxidants, and phosphorus antioxidants
• heat stabilizers such as hindered amines, benzophenones, and imidazoles
• ultraviolet absorbers ultraviolet absorbers.
• the amount of additive may be selected appropriately, and can be added in an amount of 1 to 1000 ppm based on the polyamide. These additives may be used in combination of several types, or in a single type.
• melt spinning process it is preferable to use a single-screw or twin-screw extruder in the melting section.
• This extruder allows the polyamide resin to be guided to the polymer piping, gear pump, and spinning pack while applying an appropriate amount of pressure.
• the polyamide resin it is preferable to filter the polyamide resin with a metal fiber nonwoven filter or sand before it is discharged from the spinneret, since this stabilizes the spinning operation.
• a metal fiber nonwoven filter or sand it is necessary to perform precision filtration to remove impurities such as coarse silicon compounds so that the fiber can withstand high draw ratios, but if there are a lot of impurities, the filter will become clogged and continuous production will be impossible.
• the precision filtration is preferably performed with an opening of 50 ⁇ m or less, more preferably 30 ⁇ m or less.
• the shape of the spinneret holes may be selected according to the cross-sectional shape of the single fibers constituting the filaments to be produced.
• the yarn spun from the spinneret is solidified with cooling air, a process oil is applied, and the yarn is taken up, stretched, and heat-treated to obtain the polyamide fiber used in the present invention.
• the adhesion rate of the finishing agent applied to the yarn in the spinning process is in the range of 0.5% by weight or more and 1.5% by weight or less.
• Yarn with an adhesion rate of finishing agent of 1.5% by weight or less rarely has stickiness (tackiness) that makes it difficult for the weft yarn to fly.
• a finishing agent adhesion rate of 0.5% by weight or more can suppress the occurrence of fuzz in the single yarn during drawing in the spinning process.
• ⁇ Polyamide base fabric> In weaving, a water jet loom, an air jet loom, a rapier loom, or the like can be used as the loom.
• the airbag base fabric is a high-density woven fabric, and it is preferable to manufacture the fabric with good processability by increasing the warp tension in the warping and weaving processes.
• the warp tension is set high, the weft is inserted without a shuttle, and effective beating conditions are created to form a high-density woven fabric.
• the shuttleless insertion of the weft is performed by the loom using water, air, or rapier, and the weft is instantly transported across the width of the fabric at high speed.
• the woven fabric can be subjected to a scouring process to wash off the process oil from the polyamide fibers.
• the refining step may be performed using hot water or hot compressed water, and the treatment step may be a one-stage treatment or a multi-stage treatment having two or more stages. It is also preferable to perform refining by applying a conventionally known refining agent.
• the woven fabric is preferably heat-set in a heat-setting process.
• the heat-setting temperature is preferably 110° C. or higher and 200° C. or lower, and the heat-setting time may be appropriately selected within a range of 0.1 minutes or higher and 30 minutes or lower.
• the woven fabric is preferably dried under tension so that the shrinkage force of the woven fabric is maintained at a predetermined force. Heat-setting the woven fabric can stabilize the processability of the subsequent resin application process.
• the fabric after the scouring step may be dried as necessary before the heat setting step.
• the drying temperature is preferably in the range of 80° C. to 130° C., more preferably 100° C. to 120° C.
• the treatment time is preferably selected appropriately from 0.1 minutes to 30 minutes. The drying may be performed with the fabric in a relaxed state or in a tensed state.
• Polyamide base fabric can be used as an uncoated base fabric by subjecting polyamide woven fabric to a heat setting process. Furthermore, polyamide woven fabric can be processed into a coated airbag base fabric by applying a coating agent such as silicone or urethane to the fabric or by heat laminating a thin film.
• a coating agent such as silicone or urethane
• Methods of coating the surface of a woven fabric include immersing the fabric in a resin solution tank and then forming and homogenizing the excess resin using a mangle, vacuum, or even a coating knife; bar coating methods such as a comma coater; and spraying the resin using a spray device or forming device.
• the knife coating method is preferred from the viewpoint of applying a small amount of resin evenly.
• the coating amount is 5 g/ m2 to 100 g/ m2 , more preferably 10 g/ m2 to 70 g/ m2 , and even more preferably 15 g/ m2 to 30 g/ m2 .
• a coating amount of 5 g/m2 or more provides the required airtightness.
• a coating amount of 100 g/ m2 or less provides flexibility to the coated fabric, good storage properties, and reduced weight of the entire bag.
• a vulcanization treatment After coating, it is preferable to carry out a vulcanization treatment at 150°C to 190°C.
• the treatment time is preferably selected appropriately between 0.5 and 3.0 minutes. It is also preferable to carry out the treatment while keeping the base fabric taut so that the shrinkage force is maintained at a specified force. Heat fixing the base fabric can stabilize the dimensions of the product.
• the airbag may be appropriately selected from airbags that are commonly used for the driver's seat, passenger seat, side (including inflatable curtain), rear seat, etc., and the cut shape of the airbag body may be any shape, such as circular, oval, elliptical, rectangular, polygonal, or a combination of these, as long as it satisfies the desired deployed shape.
• the stitch shape may be a single straight line or multiple parallel straight lines, a zigzag pattern, a combination of straight lines and zigzags, a straight line and a diagonal line, etc.
• the sewing method may be a commonly used method such as a lock stitch or a double chain stitch, and the stitch pitch may be selected from the range of 20 to 60 times/10 cm.
• the sewing thread thickness may be selected from the range of 420d to 3000d, and commercially available sewing threads such as polyamide fiber, polyester fiber, vinylon fiber, aramid fiber, and glass fiber may be used as the thread material.
• Step 1 Dissolution step> A process is performed in which the polyamide is dissolved and extracted from the silicone-coated polyamide base fabric using an alcoholic solution of metal chloride.
• the shape of the polyamide base fabric used for dissolution is not particularly limited. Scraps from fabric production or used airbags may be added in their original shape, or may be cut according to the size of the device used for dissolution.
• the temperature for dissolving is not particularly limited, but is preferably 40 to 90°C, and more preferably 40 to 60°C. If it is below 40°C, dissolution will be slow, and if it exceeds 90°C, the temperature will be higher than the boiling point, which is undesirable from the standpoint of corrosiveness and decomposition.
• the dissolution may be carried out in either a batch or continuous manner.
• a batch method there is no particular limitation as to whether or not stirring is performed, but stirring is preferred, as stirring increases the dissolution rate of the polyamide solid.
• the solvent may be continuously passed through the solid, or the solution may be circulated. Circulation is preferred because it allows the amount of solvent used to be reduced.
• the shape of the container is not particularly limited, and any shape such as a tank type or a circulation type may be used.
• the container may have a mechanism that prevents contact between the part that rotates by an external power source during dissolution and the silicone-coated polyamide base fabric.
• the container may also have a mechanism for continuously collecting the silicone resin generated during dissolution.
• the dissolution time is not particularly limited, but is preferably from 5 minutes to 100 hours.
• a net bag having fine liquid passages is suspended, and equipment is used that has a structure in which silicone pieces are accumulated inside.
• the separated silicone resin and other coatings are preferably washed to recover the polyamide, since the polyamide solution is attached to them.
• the solvent for washing is not particularly limited, but a metal chloride alcohol solution is preferred.
• the metal chloride in the metal chloride alcohol include zinc chloride and calcium chloride, with calcium chloride being preferred.
• Examples of the alcohol in the metal chloride alcohol include alcohol that is a good solvent, such as methanol, ethanol, and isopropanol, with methanol being preferred.
• the washing method is not particularly limited, but examples include stirring washing in a tank-type reactor and flow washing in a filter.
• the polyamide solution from which the silicone resin and other coatings have been removed is preferably filtered using a stainless steel mesh filter or a membrane filter.
• the size of the filter opening can be appropriately selected according to the method described above for preventing the inclusion of fine silicone resin.
• the size of the filter opening is preferably 30 ⁇ m or less, more preferably 10 ⁇ m or less.
• Step 2 is a step of recovering polyamide from the polyamide solution obtained in step 1 from which the silicone resin has been removed.
• the method for precipitating the dissolved polyamide from the solution is not particularly limited, but several precipitation methods are possible depending on the dissolved state.
• the polyamide is dissolved by heating, it may be possible to cause precipitation by cooling, taking advantage of the temperature dependency of the solubility of the polyamide.
• the dissolved polyamide is precipitated from the solution containing the dissolved polyamide without adding additional solvent to the solution, thereby obtaining the precipitated polyamide.
• the polyamide may be mixed with a poor solvent for the polyamide to reduce the solubility and precipitate it.
• a poor solvent is added to a solution containing dissolved polyamide, and then the dissolved polyamide is precipitated from the solution to obtain precipitated polyamide.
• the poor solvent is not particularly limited, but examples thereof include water and alcohols such as ethanol, n-propanol, and isopropanol.
• the method of adding the poor solvent to the polyamide may be either a method of adding a polyamide solution to the poor solvent or a method of adding the polyamide to the poor solvent, and the addition speed, temperature, stirring speed, etc. during addition are not particularly limited.
• the amount of poor solvent added is not particularly limited, but is preferably 0.5 to 50 times the weight of the polyamide solution, and more preferably 1 to 10 times the weight of the polyamide solution. The smaller the amount added, the lower the recovery rate, and the larger the amount added, the larger the amount of solution becomes, requiring more time and energy for treatment.
• the solubility of the polyamide can also be reduced by reducing the concentration of calcium chloride.
• concentration of calcium chloride there are no particular limitations on the method of adding methanol to reduce the concentration of calcium chloride, but either a method of adding a polyamide solution to methanol or a method of adding polyamide to methanol may be used, and there are no particular limitations on the addition speed, temperature, stirring speed, etc.
• the shape of the container is not particularly limited, and any shape such as a tank type or a circulation type may be used.
• the precipitated polyamide is preferably recovered by solid-liquid separation. Examples of the solid-liquid separation method include filtration, centrifugation, and sedimentation. Either method may be used in a batch or continuous manner.
• the polyamide obtained by solid-liquid separation is preferably washed with a solvent.
• the washing liquid is not particularly limited, but for example, a solution having the composition of the liquid portion at the time of precipitation, a good solvent, and a solvent capable of dissolving calcium chloride and the like are used.
• the additional washing liquid used here is, for example, water, and alcohols such as methanol, ethanol, n-propanol, and isopropanol.
• the additional washing liquid is preferably methanol. Washing may be performed multiple times as necessary.
• the washing method is not particularly limited, and examples thereof include a batch washing method, a continuous washing method in which a solid is placed in a solid-liquid separation device such as a filter or a centrifugal separator and water is passed through it, and a combination of these methods.
• the recovered polyamide may be added in solution to the above-mentioned copper compounds, metal halide compounds, and stabilizers such as organic antioxidants, such as hindered phenol antioxidants, sulfur antioxidants, and phosphorus antioxidants, heat stabilizers, and light stabilizers, such as hindered amine, benzophenone, and imidazole stabilizers, and ultraviolet absorbers.
• the additives may be added in an amount of 1 to 1000 ppm relative to the polyamide. These additives may be used alone or in combination of several types.
• the polyamide After washing, the polyamide can be dried and solidified by distilling off the washing solvent through heating and/or reduced pressure to obtain a powdered polyamide.
• the present invention can provide a method for producing a polyamide composition in high yield from a composition in which a polyamide useful as an engineering plastic is coated with silicone.
• the polyamide composition of the present embodiment can be spun to obtain a fiber.
• the fiber of the present embodiment can be woven to obtain a woven fabric.
• the woven fabric of the present embodiment can be used for an airbag.
• the present specification further discloses an invention related to a method for producing a polyamide solution.
• the method for producing a polyamide solution of the present disclosure may be, for example, a method for producing a polyamide solution that efficiently dissolves polyamide from a polyamide-containing material.
• the method for producing a polyamide solution includes the steps of placing a polyamide-containing material containing polyamide and a component insoluble in a metal chloride alcohol solution into a container having a liquid passage made of an insoluble resin, adding the metal chloride alcohol solution containing a metal chloride and alcohol, stirring at 120°C or less to dissolve the polyamide, and separating the insoluble component into the container (sometimes referred to as a "separation step" in this specification). Other steps may also be included.
• polyamide is dissolved from a polyamide-containing material.
• the polyamide-containing material is a recycled polyamide raw material, and examples of the polyamide-containing material include fibers using polyamide as a raw material, and process waste materials and waste materials of molded products such as automobile parts and electrical appliance parts.
• Specific examples of the polyamide-containing material include, but are not limited to, process waste materials and waste materials of clothing, airbags, tire cords, engine compartments, intake systems, fuel system parts, connectors, fishing nets, UD tapes, etc.
• the polyamide-containing material contains at least a polyamide and a component insoluble in an alcohol solution of a metal chloride.
• the total mass ratio of the component insoluble in an alcohol solution of a metal chloride and the polyamide to 100% by mass of the polyamide-containing material is preferably 50 to 100% by mass, more preferably 60% by mass or more, further preferably 70% by mass or more, and particularly preferably 80% by mass or more.
• the mass ratio of the polyamide relative to 100% by mass of the polyamide-containing material is preferably 10 to 100% by mass, more preferably 20 to 99% by mass, and further preferably 70 to 98% by mass.
• the insoluble matter in the alcohol solution of the metal chloride include silicone, carbon fiber, glass fiber, polyolefins such as polyethylene and polypropylene, polyester, fluororesin, etc.
• the insoluble matter may be the component remaining after mixing a sample with an alcohol solution of the metal chloride (e.g., a 20 wt % solution of calcium chloride in methanol) in an amount 10 times by mass and stirring at a temperature of 60° C. for 24 hours.
• an alcohol solution of the metal chloride e.g., a 20 wt % solution of calcium chloride in methanol
• Metal chloride alcohol solution In the manufacturing method according to the embodiment of the present disclosure, an alcoholic solution of a metal chloride is used to dissolve the polyamide.
• the metal chloride alcohol solution contains a metal chloride and an alcohol, and may further contain other components.
• the total mass ratio of the metal chloride and the alcohol to 100 mass% of the metal chloride alcohol solution is preferably 80 mass% or more, more preferably 90 mass% or more, and even more preferably 100 mass%.
• the metal chloride is not particularly limited as long as it dissolves in the alcohol used, but is preferably any one of calcium chloride, zinc chloride, and lithium chloride because of its high solubility in polyamide. It may be used alone or in combination. Either a hydrate or an anhydride may be used, but it is preferable to use an anhydride from the viewpoint of the solubility of polyamide.
• the water content in the metal chloride alcohol solution is preferably 15 wt % or less, more preferably 10 wt % or less, and even more preferably 7 wt % or less.
• the water content in the metal chloride alcohol solution can be measured by a known method (e.g., a Karl Fischer moisture meter).
• alcohols having 1 to 4 carbon atoms are preferred because they have high solubility for the metal chlorides, with methanol and ethanol being particularly preferred, and methanol being the most preferred.
• the solubility of polyamide in the metal chloride alcohol solution is preferably a maximum of 1 wt% or more at 120°C or less. More preferably, it is a maximum of 3 wt% or more, and even more preferably, it is a maximum of 5 wt% or more. Also, from the viewpoint of achieving a moderate viscosity and good handling properties, it is preferably a maximum of 20 wt% or less, more preferably a maximum of 18 wt% or less, and even more preferably a maximum of 15 wt% or less.
• the manufacturing method of the embodiment of the present disclosure uses a container made of an insoluble resin and having a liquid passage hole.
• the container may consist of only the insoluble resin, or may contain other components.
• the insoluble resin refers to a resin that is insoluble in a metal chloride alcohol solution.
• insoluble means that the weight loss when immersed in a metal chloride alcohol solution at 120° C. for 24 hours is 1 wt % or less.
• the insoluble resin is not particularly limited, but from the viewpoints of ease of processing, flexibility, ease of introduction into a reactor, and low risk of equipment damage, preferred examples include polyethylene, polypropylene, polyurethane, polystyrene, polydimethylsiloxane, and polyester. They may be used alone or in combination.
• the above-mentioned liquid passage holes separate impurities such as those insoluble in the alcohol solution of metal chlorides as insoluble matter within the container, and selectively allow the solution to pass through.
• impurities such as those insoluble in the alcohol solution of metal chlorides as insoluble matter within the container
• the mesh size it is desirable for the mesh size to be 0.05 cm to 10 cm.
• the liquid passage holes may be punched holes or mesh-like.
• the polyamide-containing material By placing the polyamide-containing material in the container with a liquid passage, even if the impurities are fragile, they are less likely to be cut more than necessary by stirring and mixing, so they can be used in conjunction with a stirrer.
• the container with a liquid passage hole can be of a size that can be poured through the manhole of the reactor, so no special equipment or operations are required.
• multiple containers can be used, allowing the amount of liquid to be poured in to be increased.
• Containers with liquid passage holes can be used by simply throwing them into the reactor without fixing them.
• the container rotates when stirred, preventing the liquid passage holes from becoming clogged with impurities. Also, as long as the liquid passage holes are in one direction and not fixed, there is no problem with hanging them.
• the temperature at which the polyamide-containing material is stirred in the metal chloride alcohol solution is 120° C. or lower. If the temperature is 120° C. or lower, decomposition of the polyamide due to alcoholysis can be suppressed.
• the temperature is preferably 100° C. or lower, more preferably 80° C. or lower.
• the temperature is preferably 0° C. or higher, more preferably 10° C. or higher, and even more preferably 20° C. or higher.
• the amount of the metal chloride alcohol solution added is preferably at least twice the mass of the polyamide-containing material, and from the viewpoint of the efficiency of dissolving the polyamide, is more preferably 3 to 100 times, even more preferably 5 to 50 times, and particularly preferably 10 to 20 times.
• the polyamide-containing material may be chopped into pieces of a size that will prevent residues, such as those insoluble in the metal chloride alcohol solution, from passing through the liquid passage hole and then placed in the container.
• the polyamide solution may be further subjected to solid-liquid separation in order to remove the insoluble impurities contained in the polyamide solution after the separation step and discharged from the container through the liquid passage hole. Since most of the impurities are separated in the container in the separation step, the filterability is good.
• the solid-liquid separation method include filtration and centrifugation. Either method may be a batch type or a continuous type.
• Polyamide can be produced by precipitating the polyamide from the polyamide solution obtained by the manufacturing method of the embodiment of the present disclosure.
• the precipitation method is not particularly limited, but possible methods include crystallization by cooling, which utilizes the temperature dependency of the solubility of polyamide, and a method of lowering the solubility by mixing with a poor solvent for polyamide, thereby causing precipitation.
• the poor solvent is not particularly limited.
• the solubility of polyamide can also be lowered by lowering the concentration of a metal chloride (e.g., calcium chloride).
• the poor solvent may be added by either adding a polyamide solution to a poor solvent or adding a poor solvent to the polyamide, and the addition rate, temperature, stirring speed, etc. during addition are not particularly limited.
• the precipitated solid may be separated from the solution.
• Methods for solid-liquid separation include filtration, centrifugation, and sedimentation. Either method may be used in a batch or continuous manner.
• the solid obtained by solid-liquid separation may be washed with a solvent.
• a solvent there are no particular limitations on the solvent, but it is preferable to use a solution with the same composition as the liquid portion at the time of precipitation, a good solvent, or a solvent that can dissolve metal chlorides.
• the metal chloride alcohol solution contained in the polyamide solution after separation of the polyamide may be concentrated, purified and reused.
• a polyamide solution having a low mass ratio of impurities such as insoluble matter in the alcohol solution of a metal chloride can be efficiently obtained.
• the polyamide solution obtained by the manufacturing method according to the embodiment of the present disclosure can be used as a raw material for precipitating and regenerating polyamide.
• the precipitated polyamide can be used as a raw material for polyamide fibers, polyamide base fabrics, airbags, etc.
• the manufacturing method of the embodiment of the present disclosure can efficiently separate impurities from polyamide-containing materials without using special equipment or reactors, and is therefore expected to be applicable to mass production of polyamide solutions and polyamide recycling.
• the method for GPC analysis is as follows:
• the method for measuring dynamic viscoelasticity is as follows:
• the method for measuring fineness is as follows:
• the methods for measuring tensile strength, tensile strength, and elongation are as follows.
• the method for evaluating the finishing agent adhesion rate is as follows:
• the methods for measuring the boiling water shrinkage rate and the 3-month shrinkage reduction rate are as follows.
• the method for evaluating yarn breakage during spinning is as follows.
• the method for evaluating weaving defects is as follows:
• Weaving bars are defects that occur mainly due to density variations in the base fabric, resulting in poor appearance in the form of wrinkle patterns in the weft and width directions of the base fabric.
• the evaluation method involves placing the fabric on an inspection table and inspecting it, and a technician with more than three years of experience in airbag base fabric inspection visually inspects the fabric to determine whether or not there are wrinkle patterns in the weft and width directions of the base fabric before and after the change in the weft yarn supply package. Ten points on the base fabric at the change in the weft yarn supply package were checked, and defects were judged according to the following criteria.
• B Wrinkle pattern is observed, but density variation is less than ⁇ 5%.
• C Wrinkle pattern is observed, and density variation is ⁇ 5% or more.
• Example 1 50 kg of polyamide 66 base cloth (hereinafter, "coated base cloth") composed of 90 wt% polyamide 66 and 10 wt % silicone resin was cut into approximately 20 cm squares, and then evenly packed into 20 cylindrical containers made of polyethylene mesh with a diameter of 20 cm, a height of 20 cm, and an opening of 5 mm. Next, 480 kg of methanol (manufactured by Wako Pure Chemical Industries, Ltd.) and 120 kg of anhydrous calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a 1 m3 glass-lined reaction kettle and mixed with a stirring blade to prepare a 20 wt% calcium chloride methanol solution.
• coated base cloth composed of 90 wt% polyamide 66 and 10 wt % silicone resin was cut into approximately 20 cm squares, and then evenly packed into 20 cylindrical containers made of polyethylene mesh with a diameter of 20 cm, a height of 20 cm, and an opening of 5 mm.
• the cylindrical container filled with the polyamide 66 base cloth was immersed and stirred at 60 ° C for 24 hours to dissolve the polyamide. After dissolution, the silicone resin, which is an impurity, was separated in the cylindrical container.
• the obtained polyamide solution was pressure-filtered using a polyethylene filter with an opening of 10 ⁇ m to remove a small amount of silicone resin that had leaked. The filterability was good.
• the filtrate was then dropped into 600 kg of methanol to precipitate a solid.
• the precipitated solid was separated by pressure filtration, mixed with 300 kg of water, and washed by vacuum filtration. After washing with water was repeated five times, the mixture was dried under reduced pressure at 80° C. to recover 40 kg of polyamide (regenerated polyamide composition).
• the resulting recycled polyamide composition was analyzed by X-ray fluorescence analysis and found to contain 300 ppm of silicon atoms and 1,230 ppm of polyamide components (oligomers) having a degree of polymerization of 5 or less. This operation was repeated several times to obtain a powder, which was melted at 300°C using an extruder and spun by a melt spinning method with a residence time of 180 seconds at 290°C. The spun polymer was cooled and solidified by cold air to form a thread. An aliphatic synthetic ester spinning oil was applied to the solidified thread, which was then stretched and heat-treated to obtain a regenerated polyamide 66 fiber filament with a total fineness of 233 dtex and a single thread count of 36.
• the regenerated polyamide 66 fiber When the regenerated polyamide 66 fiber was analyzed by X-ray fluorescence analysis, it contained 320 ppm of silicon atoms. In addition, the content of polyamide components (oligomers) with a degree of polymerization of 5 or less was 4850 ppm. This fiber was warped without twist or sizing, and the same yarn was used for the weft to produce a plain weave of a regenerated polyamide 66 base fabric at a rotation speed of 650 rpm on a water jet loom having a width of 2.0 m. The evaluation results of the obtained regenerated polyamide 66 fibers and regenerated polyamide 66 base fabric are shown in Table 1.
• Example 2 The same procedure as in Example 1 was repeated, except that in the spinning process, regenerated polyamide 66 fiber filaments with a total fineness of 490 dtex and a single yarn count of 136 were used. The results are shown in Table 1 below.
• Example 3 The same procedure as in Example 2 was repeated, except that 25 kg of the coated base fabric and 25 kg of 100 wt % polyamide 66 base fabric (hereinafter referred to as "uncoated base fabric") were used in the production process of the polyamide composition. The results are shown in Table 1 below.
• Example 4 The same procedure as in Example 2 was repeated, except that 10 kg of the coated base fabric and 40 kg of the uncoated base fabric were used in the production process of the polyamide composition. The results are shown in Table 1 below.
• Example 5 The same procedure as in Example 2 was carried out except that in the dissolution step, the openings of the 20 cylindrical containers were set to 10 mm. The results are shown in Table 1 below.
• the relative viscosity ⁇ r was measured by dissolving 2.5 g of a sample in 25 cc of concentrated sulfuric acid (98%) and measuring it with an Ostwald viscometer at a constant temperature in a thermostatic bath (25°C).
• the obtained polymer was subjected to the same melt spinning process and weaving process as in Example 2. The results are shown in Table 1. Although high strength yarn could be spun, poor weaving bars occurred when the yarn was fed at a time separate from the production deadline in airbag weaving.
• Example 6 The pellets obtained in Comparative Example 1 and the powder obtained in Example 1 were fed in equal amounts to an extruder, and the melt spinning process and weaving process were carried out in the same manner as in Example 2. The results are shown in Table 1 below.
• Example 7 The pellets obtained in Comparative Example 1 and the powder obtained in Example 5 were fed in equal amounts to an extruder, and the melt spinning process and weaving process were carried out in the same manner as in Example 2. The results are shown in Table 1 below.
• Example 2 The same procedure as in Example 2 was repeated except that 50 kg of uncoated base fabric was used in the polyamide composition production process. The results are shown in Table 1 below. The spinning of high-strength yarn was poor. This is thought to be due to the loss of plasticity of the low molecular weight polyamide.
• Example 4 The same procedure as in Example 2 was repeated, except that 3 kg of the coated base fabric and 47 kg of the uncoated base fabric were used in the production process of the polyamide composition. The results are shown in Table 1. The amount of silicon compound in the polyamide was small, and the stretchability was poor.
• Example 5 The same procedure as in Example 2 was carried out except that the dissolution step was carried out without using a cylindrical vessel. The results are shown in Table 1. The spinning filtration pressure increased too rapidly and spinning was not possible.
• the silicone-coated polyamide 66 base fabric (hereinafter referred to as polyamide 66 base fabric) used in Example 8 and Comparative Examples 6 and 7 uses a base fabric in which 10% of its weight is made of silicone resin.
• polyamide 66 base fabric was immersed in methanol and polyamide components with a degree of polymerization of 5 or less were extracted and quantified, it was 0.9 wt%.
• Example 8 the YI (ASTM E313) value was used to measure the coloration of the recycled polyamide composition.
• the specific analysis method is shown below.
• Example 8 10g of polyamide 66 base cloth and 100g of 20wt% calcium chloride methanol solution in a polyethylene mesh bag were added to a 300mL glass bottle containing a stirrer, and the mixture was placed in a water bath at 60°C. The mixture was stirred with a magnetic stirrer for 12 hours to dissolve the polyamide (polyamide 66) contained in the polyamide 66 base cloth, thereby obtaining a mixture of polyamide solution (polyamide 66 solution) and silicone resin. The mixture of polyamide solution and silicone resin was passed through a stainless steel mesh with a mesh size of 1mm and a stainless steel mesh with a mesh size of 500 ⁇ m to remove the silicone resin.
• the removed silicone resin was returned to the original 300mL glass bottle, washed with 5g of 20wt% calcium chloride methanol solution, and separated from the polyamide solution (washing liquid after washing) through a stainless steel mesh again.
• the entire recovered polyamide solution was transferred to a 1000mL beaker, and 500g of methanol was added while stirring to obtain a polyamide (polyamide 66) solid precipitate.
• the resulting solid precipitate was filtered and collected through a 1 ⁇ m membrane filter.
• the solid precipitate obtained after filtration was thoroughly washed with water.
• the washed solid precipitate was dried by heating in a vacuum dryer at 40° C. to obtain 8.8 g (yield 97.8%) of a regenerated polyamide composition (regenerated polyamide 66 composition).
• the resulting regenerated polyamide composition was analyzed by X-ray fluorescence analysis and found to contain 400 ppm of silicon atoms, 300 ppm of calcium atoms, and 120 ppm of polyamide components having a degree of polymerization of 5 or less.
• the resulting recycled polyamide composition had a YI of 6.8.
• Regenerated polyamide was obtained in the same manner as in Example 1, without using a polyethylene mesh bag.
• the content of silicon atoms was 1500 ppm
• calcium atoms was 300 ppm
• the content of polyamide components with a degree of polymerization of 5 or less was 130 ppm.
• the resulting recycled polyamide composition had a YI of 20.
• regenerated polyamide composition (regenerated polyamide 66 composition) (yield 95.5%).
• the resulting regenerated polyamide composition was analyzed by X-ray fluorescence analysis and found to contain 20,000 ppm of silicon atoms, no detected calcium atoms, and 7,000 ppm of polyamide components with a degree of polymerization of 5 or less. Since the color of the resulting recycled polyamide composition was non-uniform, it was melted once at 280° C. and pelletized. The YI of the resulting pellets was 37.5.
• Example 9 1 kg of process waste of an airbag composed of 90 wt% polyamide 6,6 and 10 wt% silicone resin was cut into approximately 10 cm squares, and then evenly filled into three cylindrical containers made of polyethylene mesh with a diameter of 10 cm, a height of 10 cm, and an opening of 5 mm. Next, 12 kg of methanol (manufactured by Wako Pure Chemical Industries, Ltd.) and 3 kg of anhydrous calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a 20 L separable flask and mixed with a mechanical stirrer to prepare a 20 wt% calcium chloride methanol solution.
• methanol manufactured by Wako Pure Chemical Industries, Ltd.
• 3 kg of anhydrous calcium chloride manufactured by Wako Pure Chemical Industries, Ltd.
• the cylindrical container filled with the process waste of the airbag was immersed and stirred at 60 ° C for 24 hours to dissolve the polyamide.
• the silicone resin which is an impurity, was separated in the cylindrical container.
• the obtained polyamide solution was passed through a polyethylene mesh with an opening of 500 ⁇ m under its own weight to remove a small amount of silicone resin that had leaked, and then dropped into 30 kg of methanol to precipitate a solid.
• the precipitated solid was separated by pressure filtration, mixed with 20 kg of water, and washed by vacuum filtration. After washing with water was repeated five times, the mixture was dried at 80° C. under reduced pressure to recover 800 g of polyamide.
• Example 10 50 kg of process waste of airbags composed of 90 wt% polyamide 6,6 and 10 wt% silicone resin was cut into approximately 20 cm squares, and then evenly packed into 20 cylindrical containers made of polyethylene mesh with a diameter of 20 cm, a height of 20 cm, and an opening of 5 mm. Next, 480 kg of methanol (manufactured by Wako Pure Chemical Industries) and 120 kg of anhydrous calcium chloride (manufactured by Wako Pure Chemical Industries) were placed in a 1 m3 glass-lined reaction kettle and mixed with a stirring blade to prepare a 20 wt% calcium chloride methanol solution.
• methanol manufactured by Wako Pure Chemical Industries
• anhydrous calcium chloride manufactured by Wako Pure Chemical Industries
• the cylindrical container filled with the process waste of the airbags was immersed and stirred at 60 ° C for 24 hours to dissolve the polyamide.
• the silicone resin which is an impurity, was separated in the cylindrical container.
• the obtained polyamide solution was pressure-filtered using a polyethylene filter with an opening of 10 ⁇ m to remove a small amount of silicone resin that had leaked. The filterability was good.
• the filtrate was dropped into 600 kg of methanol to precipitate a solid.
• the precipitated solid was separated by pressure filtration, mixed with 300 kg of water, and washed by filtration under reduced pressure. After washing with water was repeated five times, the mixture was dried under reduced pressure at 80° C. to recover 40 kg of polyamide.
• Example 11 50 g of UD tape process waste material consisting of 30 wt% random copolymer of polyamide 6,6 and polyamide 6I and 70 wt% carbon fiber was cut into approximately 5 cm squares and then filled into one cylindrical container with a diameter of 5 cm and a height of 5 cm made of polyester mesh with an opening of 1.5 mm. Next, 400 g of methanol (manufactured by Wako Pure Chemical Industries, Ltd.) and 100 g of anhydrous calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a separable flask and mixed with a mechanical stirrer to prepare a 20 wt% calcium chloride methanol solution.
• methanol manufactured by Wako Pure Chemical Industries, Ltd.
• anhydrous calcium chloride manufactured by Wako Pure Chemical Industries, Ltd.
• the cylindrical container filled with the UD tape process waste material was immersed and stirred at 60 ° C for 24 hours to dissolve the polyamide. After dissolution, the carbon fiber, which is an impurity, was separated in the cylindrical container, and no leakage outside the container was visible.
• the polyamide solution was dropped into 1.5 kg of a mixed solution of 50 wt% methanol and 50 wt% water to precipitate a solid, and the precipitated solid was separated by vacuum filtration. The mixture was then mixed with 1 kg of water and filtered under reduced pressure for washing. After washing with water was repeated five times, the mixture was dried under reduced pressure at 80° C. to recover 10 g of polyamide.
• Example 12 50 g of tire cord made of 95 wt % or more polyamide was cut to a length of about 10 cm, and then filled into one cylindrical container made of polyester mesh with a mesh size of 0.5 mm and a diameter of 5 cm and a height of 5 cm. Next, 400 g of methanol (manufactured by Wako Pure Chemical Industries, Ltd.) and 100 g of anhydrous calcium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a separable flask and mixed with a mechanical stirrer to prepare a 20 wt % calcium chloride methanol solution. The cylindrical container filled with the tire cord was immersed and stirred at 60 ° C for 24 hours to dissolve the polyamide.
• Example 13 A polyamide solution was prepared from process waste of airbags in the same manner as in Example 1, except that zinc chloride was used instead of calcium chloride, and 800 g of polyamide was recovered.
• the present invention provides a polyamide composition that is less likely to clog the flow paths of filters and other equipment during melt processing such as melt spinning, allowing the equipment to operate continuously for long periods of time. It also provides polyamide fibers that can improve the quality of airbag base fabrics.

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• 2023
  • 2023-10-27 WO PCT/JP2023/038982 patent/WO2024095932A1/ja not_active Ceased
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