Classifications

• • 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
  • D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/92—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds of polyesters
• • 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
  • D01F6/62—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters

Definitions

• the present invention relates to polyester fibers having high resistance to hydrolysis, in particular monofilaments, which can be used in particular in applications for processing and / or preserving foodstuffs.
• polyester fibers in particular monofilaments for technical applications, are in most cases subjected to high mechanical and / or thermal stresses during use.
• the material must have good dimensional stability and constancy of force-elongation properties over as long as possible usage periods.
• Molding compositions with high chemical and physical resistance and their use for fiber production are known. Commonly used materials for this are polyesters. It is also known to combine these polymers with other materials, for example, to set the hydrolysis resistance targeted.
• polyester-based chemical fibers are approved for contact with food.
• polyesters are prone to hydrolytic degradation.
• polyethylene terephthalate molding compositions containing a polyolefin copolymer, the glycidyl ester of an ethylenically unsaturated carboxylic acid and the barium salt of a long-chain fatty acid.
• the present invention has the object to provide polyester fibers which have excellent hydrolytic stability and which are suitable for the production of food commodities such as conveyor belts or sieves.
• the present invention provides polyester fibers, in particular monofilaments, which on the one hand can be used in the processing and / or storage of foodstuffs and which have one opposite to the other unmodified and having a same carboxyl group number having polyester improved hydrolysis resistance.
• the invention relates to polyester fibers having a content of free carboxyl groups of less than 3 meq / kg, which have been stabilized with an epoxy composition comprising at least one epoxidized fatty acid ester having an epoxide content of at least 1.5 wt.%, Based on the composition.
• the fiber-forming polyesters may be of any nature as long as they are melt-formable and impart to the fiber the properties desired for the particular application.
• thermoplastic polyesters and / or aromatic liquid crystalline polyesters are known per se.
• polyesters such as polycarbonate or aliphatic / aromatic polyesters such as polybutylene terephthalate, polycyclohexanedimethyl terephthalate, polyethylene naphthalate or especially polyethylene terephthalate, but also completely aromatic, liquid crystalline polyesters such as Polyoxibenzonaphtoat.
• Building blocks of thread-forming polyesters are preferably diols and dicarboxylic acids, or appropriately constructed oxycarboxylic acids.
• the main acid constituent of the polyesters is terephthalic acid or cyclohexanedicarboxylic acid, but other aromatic and / or aliphatic or cycloaliphatic dicarboxylic acids may also be suitable, preferably para or transitive aromatic compounds, for example 2,6-naphthalenedicarboxylic acid or 4,4'-biphenyldicarboxylic acid, but also p-hydroxybenzoic acid.
• Aliphatic dicarboxylic acids such as adipic acid or sebacic acid are preferably used in combination with aromatic dicarboxylic acids.
• Typical suitable dihydric alcohols are aliphatic and / or cycloaliphatic and / or aromatic diols, for example ethylene glycol, propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol but also hydroquinone.
• polyesters which have repeating structural units which are derived from an aromatic dicarboxylic acid and an aliphatic and / or cycloaliphatic diol.
• thermoplastic polyesters used are in particular selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexanedimethanol terephthalate, polycarbonate or a copolycondensate comprising polybutylene glycol, terephthalic acid and naphthalenedicarboxylic acid units.
• thermoplastic polyesters used are aromatic, liquid-crystalline polyesters, in particular polyesters comprising p-hydroxybenzoate units.
• the inventively stabilized polyester moldings show a significant reduction in the degradation tendency of the polyester, so that, for example, lifetimes of monofilaments can be achieved, which are equivalent to those of monofilaments based on highly resistant fiber materials, such as polyarylene sulfides or oxides.
• the polyesters used according to the invention usually have Solution viscosities (IV values) of at least 0.60 dl / g, preferably from 0.60 to 1.05 dl / g, particularly preferably from 0.62 to 0.93 dl / g, (measured at 25 ° C in Dichloroacetic acid (DCE)).
• IV values Solution viscosities
• the hydrolysis stabilizers used according to the invention give the polyester fibers excellent hydrolysis protection without being toxic.
• hydrolysis stabilizers used according to the invention can be prepared by simply mixing the components.
• the epoxidized fatty acid esters used as hydrolysis protectors used in the invention are derived from any fatty acids which are esterified with any, preferably aliphatic alcohols.
• the fatty acids have six to thirty carbon atoms, especially ten to twenty carbon atoms.
• the epoxidized fatty acid esters used to prepare the hydrolysis stabilizers used in the invention have at least one double bond. This may be in the alcohol part or preferably in the acid part. It is also fatty acid esters with multiple double bonds used as starting materials. These compounds are, in particular, esters of the so-called omega fatty acids which are found, for example, in fish oils.
• the alcohols may be tertiary, secondary or primary aliphatic alcohols and typically have from one to ten carbon atoms.
• Preferably used hydrolysis stabilizers comprise a) epoxidized fatty acid alkyl esters and b) epoxidized fatty acid glycerides.
• the epoxidized fatty acid glycerides used as component b) are derived from any fatty acids which are esterified with glycerol or partially esterified.
• the fatty acids Preferably, the fatty acids have six to thirty carbon atoms, in particular ten to twenty carbon atoms.
• the fatty acids are preferably unsaturated and may have one or more double bonds.
• Epoxidized fatty acid glycerides which are particularly suitable for preparing the hydrolysis protection agent used according to the invention are epoxidized soybean oil, epoxidized linseed oil, epoxidized rapeseed oil, epoxidized sunflower oil and epoxidized fish oil.
• the epoxidized fatty acid esters used are preferably the thermally stable C 1 -C 8 -alkyl esters, in particular the 2-ethylhexyl esters, unsaturated fatty acids or fatty acid mixtures of rapeseed oil, linseed oil, soybean oil or fish oil.
• the epoxidized products can be prepared by per se known epoxidation of the corresponding starting materials (esters or glycerides) with per compounds, such as peracids or hydrogen peroxide, or with activated oxygen, for example with ozone.
• the epoxide content of the hydrolysis stabilizer used according to the invention can likewise vary within a wide range, but amounts to at least 1.5% by weight of oxygen, based on the total amount of epoxidized components.
• the epoxide content is in the range of 1.5 to 15% by weight, more preferably 4 to 8% by weight.
• the amount ratio of component a) to b) can vary within wide limits. Typically, the amount of component a) 90 to 10 wt.% And the amount of component b) 10 to 90 wt.%, Based on the total amount of components a) and b).
• the type and amount of components a) and b) are preferably chosen so that liquid products are obtained.
• the hydrolysis protection agent used according to the invention preferably also contains at least one carbodiimide as component c).
• the hydrolysis protection agent preferably comprises 90 to 10% by weight of component a), 9.9 to 60% by weight of component b) and 0.1 to 30% by weight of component c) (based on the total amount of components a) to c)).
• the NCN content here is at least 2.0% by weight, based on the total amount of components a) to c).
• hydrolysis protection agent which consists exclusively of components a) and b).
• the amount of epoxide composition added in the preparation of the polyester fibers according to the invention or in the preparation of the polyester should be chosen such that the desired content of free carboxyl groups is from 0 to 3 meq / kg, preferably not more than 2 meq / kg polyester.
• the amount of epoxy composition can be chosen so that after setting the desired content of free carboxyl groups virtually all epoxy groups are consumed.
• the amount of epoxy composition is 0.05 to 30% by weight, based on the polyester fiber.
• 0.1 to 10 wt.% are used.
• polyester fibers are to be understood as meaning any polyester-containing fibers.
• filaments or staple fibers which consist of several individual fibers, but in particular monofilaments.
• polyester fibers according to the invention can be prepared by processes known per se.
• the amount of the epoxy composition should be chosen so that the content of free carboxyl groups in the polyester fiber does not exceed 3 meq / kg.
• the amount of the epoxy composition is to be chosen so that the content of free carboxyl groups in the polyester fiber does not exceed 3 meq / kg.
• the polyester filament formed is drawn one or more times.
• polyester fibers according to the invention can be present in any desired form, for example as multifilaments, as staple fibers or in particular as monofilaments.
• the titer of the polyester fibers according to the invention can likewise vary within wide limits. Examples are 100 to 45,000 dtex, in particular 400 to 7,000 dtex.
• polyester raw material can be used. This typically has levels of free carboxyl groups of 15 to 50 meq / kg of polyester. Preference is given to using polyester raw materials produced by solid phase condensation; in these, the content of free carboxyl groups is typically 5 to 20 meq / kg, preferably less than 8 meq / kg of polyester.
• an already hydrolysis-stabilized polyester raw material can also be used to produce the polyester fibers according to the invention.
• the stabilizer mixture comprising components a) and b) was added during the polycondensation and / or at least one of the monomers.
• this polyester raw material has a content of carboxyl groups of less than or equal to 3 meq / kg.
• the hot polymer filament is cooled, e.g. in a cooling bath, preferably in a water bath, and then wound up or peeled off.
• the removal speed is greater than the injection rate of the polymer melt.
• polyester fiber produced in this way is then preferably subjected to a post-drawing, particularly preferably in several stages, in particular a two- or three-stage post-drawing, with a total draw ratio of 3: 1 to 8: 1, preferably 4: 1 to 6: 1.
• the take-off speed is usually 10 to 100 meters per minute, preferably 10 to 40 meters per minute.
• polyester fibers according to the invention may contain, in addition to the hydrolysis stabilizer, further auxiliaries.
• auxiliaries include processing aids, antioxidants, plasticizers, lubricants, pigments, matting agents, viscosity modifiers or crystallization accelerators.
• processing aids are siloxanes, waxes or longer-chain carboxylic acids or their salts, aliphatic, aromatic esters or ethers.
• antioxidants are phosphorus compounds, such as phosphoric acid esters or sterically hindered phenols.
• pigments or matting agents examples include organic dye pigments or titanium dioxide.
• viscosity modifiers are polybasic carboxylic acids and their esters or polyhydric alcohols.
• polyester fibers according to the invention are used in particular for the production of articles used in the processing and / or storage of foodstuffs.
• polyester fibers of the invention are preferably used for the production of fabrics, in particular fabrics, which are used in the food processing industry.
• polyester fibers in the form of monofilaments according to the invention relates to their use as conveyor belts or as components of conveyor belts in the food processing industry.
• PET polyethylene terephthalate
• hydrolysis stabilizer hydrolysis stabilizer
• PET a solid-phase-condensed type having free carboxyl group content of about 7 meq / kg was used.
• the hydrolysis stabilizer used was a mixture of epoxidized fatty acid alkyl esters and epoxidized fatty acid glycerides (test product Synbio Hystab from Shufer-Additivsysteme GmbH, Slevogtweg 10, 67122 Altrip).

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)
• Polyesters Or Polycarbonates (AREA)
• Woven Fabrics (AREA)
• Belt Conveyors (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (7)

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• 2003
  • 2003-12-19 DE DE10359763A patent/DE10359763B4/de not_active Expired - Fee Related
• 2004
  • 2004-11-22 PT PT04027655T patent/PT1544331E/pt unknown
  • 2004-11-22 ES ES04027655T patent/ES2332718T3/es active Active
  • 2004-11-22 DE DE502004010034T patent/DE502004010034D1/de active Active
  • 2004-11-22 EP EP04027655A patent/EP1544331B1/de not_active Not-in-force
  • 2004-11-22 AT AT04027655T patent/ATE442469T1/de not_active IP Right Cessation
  • 2004-12-15 US US11/013,114 patent/US20050137299A1/en not_active Abandoned
  • 2004-12-17 JP JP2004365326A patent/JP2005179879A/ja not_active Withdrawn

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