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
  • 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
  • D01F8/14—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyester as constituent
• • 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
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2929—Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• • 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
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2929—Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
  • Y10T428/2931—Fibers or filaments nonconcentric [e.g., side-by-side or eccentric, etc.]

Definitions

• the present invention relates to heavy-duty core / sheath monofilaments for technical applications with high dimensional stability and abrasion resistance and very good heat and hydrolysis resistance as well as technical products made therefrom, in particular paper machine screens, fabrics for screen printing and for technical filter materials.
• the core / sheath monofilaments according to the invention have a polyester core and a sheath made from a mixture of a thermoplastic polyester and a thermoplastic elastomeric copolyether ester.
• paper machine screens for the forming and dryer sections are predominantly made from polyethylene terephthalate monofilaments in the warp and weft. These sieves have the disadvantage that they lengthen (lengthen) in the running direction in the course of sieving on the paper machine and therefore retensioning must take place.
• Screen printing fabrics are nowadays made from relatively fine titre monofilaments made of polyethylene terephthalate or polyamide in warp and weft.
• the main disadvantage of the polyamide screens is their high water absorption, which has a negative effect on the elasticity, to which very high demands have to be made for screen printing fabrics; with polyester screens, their inherently poorer elastic behavior interferes. As a result, only relatively short service lives are achieved in such known screens.
• the jacket polyester can contain, for example, isophthalic acid, adipic acid or sebacic acid residues or longer-chain diol residues such as diglycol, butanediol or polyethylene glycol residues, where the polyethylene glycol residues can have a molecular weight of about 600 to 1500.
• the jacket polyester can be, for example, a polyethylene terephthalate which is modified with 8% by weight of polyethylene glycol residues. Although this amount of modifier is sufficient to influence the strength properties and the melting behavior, it does not impart any elastomeric properties to the polyester.
• polyester fibers with very different mechanical and textile properties.
• monofilaments from polyethylene terephthalate by varying the spinning and drawing and relaxation conditions, which cover a broad spectrum of the properties relevant for technical monofilaments.
• polyesters for example, polyethylene naphthalate and copolyester made from 4,4'-biphenyl-dicarboxylic acid and 2,6-naphthalene-dicarboxylic acid, as described, for example, B. have been described in European Patent Application No. 202,631. Fibers made from 4,4'-biphenyl-dicarboxylic acid and 2,6-naphthalene-dicarboxylic acid have already been proposed in WO 93/02122.
• a copolyester of 4,4'-biphenyl-dicarboxylic acid and 2,6-naphthalene-dicarboxylic acid and ethylene glycol, which is said to be suitable for the production of tire cord, has been described in Japanese Patent Application 50-135,333.
• This publication shows that such a copolyester must not contain more than 20 mol% of 4,4'-biphenyl-dicarboxylic acid, because otherwise its initial modulus and softening temperature will drop too much.
• This statement is supported in this document by exemplary embodiments, in which it is shown that the softening temperature, which is 275 ° C. for pure polyethylene naphthalate, drops to 238 ° C.
• monofilaments which have a combination of further improved mechanical properties relevant to application, high stability against actinic radiation and high chemical stability, in particular hydrolysis stability, and which are therefore accessible to an expanded range of technical applications.
• These monofilaments essentially consist of polyesters - the term "polyester” in the sense of the present invention also includes copolyesters - and have a core / shell structure.
• the present invention thus relates to monofilaments with a core / sheath structure with a core made of a thermoplastic polyester or copolyester and a sheath containing a thermoplastic polyester, which are characterized in that the polyester or copolyester of the core has a melting point of 200 to 300 ° C, preferably from 220 to 280 ° C, and at least 70 mol%, based on the totality of all polyester assemblies, from assemblies which are derived from aromatic dicarboxylic acids and from aliphatic diols, and to a maximum of 30 mol%, based on the totality of all polyester assemblies, from dicarboxylic acid assemblies which are different from the aromatic dicarboxylic acid assemblies which form the majority of the dicarboxylic acid assemblies, or from araliphatic dicarboxylic acids with one or more, preferably one or two condensed or uncondensed aromatic nuclei, or derived from cyclic or acyclic aliphatic dicarboxylic
• the jacket made of a polyester mixture of a thermoplastic polyester, the melting point of which is between 200 and 300 ° C., preferably 220 and 285 ° C., and a thermoplastic, elastomeric copolyether ester containing 40-60% by weight of longer-chain polyether diols with an average mol. contains from 600-4000 as soft segments, and which in filament form has a tensile strength (fineness-related maximum tensile strength) of 0.8 to 6.5 cN / tex, preferably 1.0 to 5.5 and an elongation at break (maximum tensile strength elongation) of 300 to 1200% , and optionally conventional non-polymeric additives.
• a tensile strength fineness-related maximum tensile strength
• 0.8 to 6.5 cN / tex preferably 1.0 to 5.5
• an elongation at break maximum tensile strength elongation
• the proportion of the sheath in the total cross-sectional area of the monofilament is 5 to 95%, preferably 10 to 60, in particular 15 to 35%, the proportion of the core 5 to 95%, preferably 40 to 90, in particular 65 to 85%.
• the symbols A 1 in the assemblies I and III denote 1,4-phenylene and D 1 ethylene, and in this polyester the assemblies I and III preferably make up at least 85 mol%, in particular at least 90 mol. % of all assemblies.
• the assemblies I and III mean in the assemblies I and III of the polyester of the core A 1 2,6-naphthylene and D 1 ethylene and preferably also make the assemblies I and III in this polyester at least 85 mol%, in particular at least 90 mol%, of all assemblies.
• the symbols A 1 in the assemblies I and III of the core polyester mean 2,6-naphthylene of the formula VI and biphenyl-1,4-diyl of formula VII and D 1 ethylene, again particularly preferred being those in which the assemblies I and III make up at least 85 mol%, in particular at least 90 mol%, of all assemblies. Furthermore, it is particularly advantageous if the standing for A 1 groups 2,6-naphthylene and biphenyl-1,4-diyl in the mole ratio of maximum 3: 1, preferably in a molar ratio between 6: there are 6: 4 and 4.
• Core polyesters are also preferred.
• the symbols A 1 in the assemblies I and III mean 1,4-phenylene and D 1 1,4-bismethylene-cyclohexane, and in particular those in which the assemblies I and III are at least 85 mol%, in particular at least 90 mol .-% of all assemblies.
• the polyester of the core expediently has a specific viscosity of 0.55 to 1.6, preferably 0.58 to 1.5, measured in a 1% strength by weight solution of the polyester in dichloroacetic acid at 25 ° C.
• the polyesters of different chemical composition can have the same average molecular weight and / or different specific viscosities with the same spinnability and / or filament strength.
• the specific viscosities of polyesters which are essentially based on polyethylene naphthalate and which provide good filaments, are in the range from 0.55 to 0.8.
• polyethylene terephthalate and its copolyesters the range is from 0.7 to 1.0
• poly (1,4-bismethylolcyclohexane) terephthalate and its modifications the range is from 1.15 to 1.5
• polybutylene terephthalate and its modifications the range is from 1.1 to 1.3 particularly useful.
• “Its modifications” are understood to mean those polyesters which, in addition to the main components mentioned, contain up to 15 mol% of the above-mentioned modifying components in the molecule.
• the polymer material of the polyester mixture of the jacket is made 1 to 99% by weight, preferably 30 to 90% by weight, in particular 50 to 80% by weight, of the thermoplastic polyester and 1 to 99% by weight, preferably 10 to 70% by weight, in particular 20 to 50% by weight, from the thermoplastic copolyether ester. It is surprising here that even very small additions of the elastomeric, thermoplastic copolyether ester bring about significant improvements in the application properties. It is therefore often sufficient to work with the smallest additional amounts in the range given above. This results in a price advantage for the monofilament according to the invention, since the elastomer additives are relatively expensive materials. In addition, of course, the addition of elastomers is measured in the context of the above quantities according to the requirements of the individual application.
• the polyester of the polyester mixture of the jacket preferably has a glass point in the range from 60 to 150 ° C., in particular from 70 to 130 ° C., a crystallization point in the range from 135 to 200 ° C., in particular from 140 to 180 ° C., and a melting point in Range from 200 ° C to 300 ° C, especially from 220 to 285 ° C.
• the polyester of the polyester mixture of the jacket consists of at least 70 mol%, based on the totality of all polyester assemblies, of assemblies which are derived from aromatic dicarboxylic acids and aliphatic diols, and a maximum of 30 mol%, based on the totality of all polyester assemblies, from dicarboxylic acid assemblies which are different from the aromatic dicarboxylic acid assemblies which form the majority of the dicarboxylic acid assemblies, or from araliphatic dicarboxylic acids having one or more, preferably one or two condensed or uncondensed aromatic nuclei, or of cyclic ones or acyclic aliphatic dicarboxylic acids with a total of 4 to 12 carbon atoms, preferably 6 to 10 carbon atoms and diol assemblies which are derived from aliphatic diols and are different from the diol assemblies which form the majority of the diol assemblies, or which are branched and / or longer-chain diols with 3 to 10, preferably 3 to 6
• a polyester can be used, for example, in which in the assemblies I and III A 1 is 1,4-phenylene and 1,3-phenylene and D 1 is ethylene, the molar ratio of 1, 4- and 1,3-phenylene is chosen so that the polyester has a melting point in the desired range.
• the polyester contained in the polyester mixture of the sheath also has a specific viscosity of 0.55 to 1.6, preferably 0.58 to 1.5, measured in a 1% by weight solution of the polyester in Dichloroacetic acid at 25 ° C, and / or if both the polyester of the core and the polyester contained in the polyester mixture of the sheath has a melting point between 200 to 300 ° C.
• polyester of the core and the polyester of the polyester mixture of the shell have the same chemical composition.
• the Polyester of the core and polyester of the polyester mixture of the jacket not more than 60 meq / kg, preferably less than 30 meq / kg, blocked carboxyl end groups and less than 5 meq / kg, preferably less than 2 meq / kg, in particular less than 1.5 mVal / kg, has free carboxyl end groups.
• the polyester of the core and the polyester of the polyester mixture of the sheath therefore preferably have end-capped carboxyl groups, for example by reaction with mono-, bis- and / or polycarbodiimides.
• the polyester of the core and the polyester of the polyester mixture of the jacket have a maximum of 200 ppm, preferably a maximum of 50 ppm, in particular 0 to 20 ppm, mono- and / or biscarbodiimides and 0.02 to 0.6% by weight, preferably 0.05 to 0.5% by weight, of free polycarbodiimide with an average molecular weight of 2,000 to 15,000, preferably of 5,000 to 10,000.
• Carbodiimide-based hydrolysis stabilizers are, for example, the ®Stabaxol types from Bayer AG.
• the core / sheath monofilaments according to the invention which consist of the above-described polyesters, in particular of polyethylene terephthalate, are not easily ignited.
• flame retardancy can be increased by using flame retardant modified polyesters.
• flame-retardant modified polyesters are known. They contain additions of halogen compounds, in particular bromine compounds, or, which is particularly advantageous, they contain phosphorus compounds which are condensed into the polyester chain.
• flame-retardant pile goods according to the invention contain, in the back and / or pile, yarns made of polyesters which in the chain contain assemblies of the formula VIII wherein R is alkylene or polymethylene with 2 to 6 C atoms or phenyl and R 1 is alkyl with 1 to 6 C atoms, aryl or aralkyl, contained in condensed form.
• R preferably denotes ethylene and R 1 denotes methyl, ethyl, phenyl, or o-, m- or p-methylphenyl, in particular methyl.
• the components of the formula VIII are expediently contained in the polyester chain up to 15 mol%, preferably 1 to 10 mol%.
• a suitable means for introducing a group of formula VIII is the commercial product ®Phospholan from Hoechst AG.
• the aromatic rings of the polyester of the core and of the polyester of the polyester mixture of the shell can be unsubstituted or can carry one or two non-reactive substituents.
• Suitable substituents are halogen atoms, preferably fluorine or chlorine, lower alkyl groups with up to 4 carbon atoms, such as. As methyl, ethyl, n-butyl isobutyl or tertiary butyl, preferably methyl, lower alkoxy groups with up to 4 carbon atoms, such as.
• the aromatic rings of the elastomeric copolyether ester of the polyester mixture of the jacket of the core-jacket monofilaments can be unsubstituted or can carry one or two substituents from the group -SO 3 H or -CH 3 to modify the properties of the copolyether ester.
• An example of a commercially available elastomeric copolyether ester which is suitable for the production of the polyester mixture of the sheath of the core / sheath monofilaments according to the invention is the product available from HOECHST under the name ®Riteflex.
• the monofilaments according to the invention expediently have a titer of 1 to 24400 dtex (in the case of a round cross section corresponding to filament diameters of 10 to 1500 ⁇ m) and a round, elliptical or n-angular cross-sectional shape, the ratio of the major axis to the minor axis being up to 10 in the case of an elliptical shape : 1 and n ⁇ 4, preferably 4 to 8.
• the core / sheath monofilaments according to the invention preferably also have the following features, which can be present individually or in combination:
• the initial module in the sense of this invention is understood to mean the slope of the secant of the force-strain diagram between the points of 0.3% and 0.5% strain.
• Particularly characteristic initial moduli are in the Range from 15 to 25 N / tex.
• the maximum tensile force stretch is usually in the range of over 7%, preferably from 8 to 18%.
• the monofilaments according to the invention may also contain small amounts of admixtures and additives of a non-polymeric nature, such as, for. B. catalyst residues, modification additives, fillers, matting agents, pigments, dyes, stabilizers, such as UV absorbers, antioxidants, hydrolysis, light and temperature stabilizers and / or processing aids, plasticizers or lubricants.
• additives are usually present in a concentration of at most 10% by weight, preferably 0.01-5% by weight, in particular 0.1-2% by weight.
• the catalyst residues can be, for example, antimony trioxide or tetraalkoxy titanates.
• Processing aids or lubricants which can be used are siloxanes, in particular polymeric dialkyl- or diarylsiloxanes, salts and waxes and longer-chain organic carboxylic acids, that is to say those with more than 6 carbon atoms, aliphatic, aromatic and / or perfluorinated esters and ethers in amounts of up to 1% by weight will.
• the monofilaments can also contain inorganic or organic pigments or matting agents, such as. B. organic dye pigments or titanium dioxide, or carbon black as a color or conductivity additive.
• stabilizers for example, phosphorus compounds, such as. B.
• viscosity modifiers and substances for modifying the crystallite melting point or the glass transition temperature or those which influence the crystallization kinetics or the degree of crystallization can be used.
• a viscosity modifier for example, polyhydric carboxylic acids or their esters, such as trimesic or trimellitic acid, or polyhydric alcohols, such as. B. diethylene glycol, triethylene glycol, glycerin or pentaerytrite. These compounds are either added to the finished polymers in a small amount or, preferably, as copolymerization constituents in the preparation of the polymers in the desired Quantity added.
• the polyester of the core and / or the polyester mixture of the jacket are colored differently.
• the different coloring can be achieved in that the polyester of the core and / or the polyester mixture of the jacket contain different dyes or in that either the polyester of the core or the polyester mixture of the jacket contain up to 5% by weight of one dye and the other filament component is natural colored.
• the dye in the core and / or in the jacket of the monofilaments is expediently a dye or pigment soluble in polyester.
• the different coloring of the core and sheath of the monofilaments according to the invention ensures that, with a certain degree of wear, the monofilaments become discolored.
• Another object of the present invention is a process for producing the core / sheath monofilaments according to the invention described above, wherein the thermoplastic polyester for the core and a polyester mixture for the sheath are melted separately in an extruder, and at melt temperatures of 230 to 330 ° C with a spinning draft of 1: 1.5 to 1: 5, preferably 1: 2 to 1: 3, spun out, cooled in a spinning bath and wound up or drawn off, the spun thread thus produced is then subjected to post-drawing in the total drawing ratio of 1: 4 to 1: 8, and then heat set at temperatures of 160 to 250 ° C, constant length or with approval of 2 to 30% shrinkage.
• a polyester or copolyester is used for the core, which has a melting point of 200 to 300 ° C, preferably 220 to 285 ° C, and at least 70 mol%, based on the totality of all polyester assemblies, from assemblies which are derived from aromatic dicarboxylic acids and from aliphatic diols, and to a maximum of 30 mol%, based on the totality of all polyester assemblies, from dicarboxylic acid assemblies which are different from the aromatic dicarboxylic acid assemblies which form the majority of the dicarboxylic acid assemblies, or from araliphatic dicarboxylic acids with one or more, preferably one or two condensed or uncondensed aromatic nuclei, or derived from cyclic or acyclic aliphatic dicarboxylic acids with a total of 4 to 12 carbon atoms, preferably 6 to 10 carbon atoms and diol assemblies which are derived from aliphatic diols and are different from the diol assemblies which form the
• a polyester mixture which consists of a thermoplastic polyester, the melting point of which is between 200 and 300 ° C., preferably 220 and 285 ° C., and a thermoplastic, elastomeric copolyether ester and, if appropriate, customary non-polymeric additives .
• Spinning can be carried out using a special spinneret provided with a central opening and one or more peripheral jacket openings for the production of core / sheath filaments.
• the melts for core and shell are then filtered in a spin pack, the thermoplastic polyester is fed to the core opening and the abrasion-resistant polyester mixture to the shell opening of a spinneret for the production of core / shell monofilaments.
• the core polyester becomes the center and the polyester mixture for the jacket of the monofilament is fed to the periphery of a spin pack and spun through a simple spinning opening.
• the polymer components for the sheath - which may contain non-polymeric constituents - are combined with one another in the desired quantity ratio immediately before the extruder inlet and the homogenization is carried out in the inlet and mixing area of the extruder screw.
• the polyesters of the core and the polyester mixture of the sheath, prior to spinning are 1.0 to 1.2 times the amount which is equivalent to the amount of free carboxyl end groups contained therein in mono -, Bis- and / or polycarbodiimides added.
• polyesters of the core and the polyester mixture of the sheath, prior to spinning contain an amount of at most 0.6% by weight of a mono- and / or biscarbodiimide and at least 0.05% by weight of one Polycarbodiimids added.
• the mono-, bis- and / or polycarbodiimides are added immediately before spinning, so that the contact time of molten polyester and carbodiimide additives is less than 5, preferably less than 3 minutes.
• Spinning is preferably carried out at a melting temperature in the range from 250 to 310 ° C. and the monofilaments are drawn off at a spinning take-off speed of 5 to 30 m per minute.
• the spinning temperature and the spinning delay which can be determined by setting the injection speed and the spinning take-off speed, and the drawing conditions are chosen so that the monofilaments according to the invention have the following parameters: An initial module at 25 ° C. of greater than 10, preferably greater than 12 N / tex, a fineness-related maximum tensile force of over 18, preferably from 20 to 45 cN / tex, a maximum tensile elongation of more than 7%, preferably 8 to 18%, a dry heat shrinkage at 180 ° C of> 0.5, preferably 1 to 25%.
• composition and spinning parameters to achieve a certain combination of monofilament properties can be carried out routinely by determining the dependence of the monofilament property under consideration on the composition of the polyester and on the spinning parameters mentioned.
• polyesters and copolyesters are prepared by polycondensation of the corresponding dicarboxylic acid and diol components, with polycondensation advantageously expediently first in the melt to an average IV value and then further condensation in the solid phase to the desired final viscosity.
• Dicarboxylic acid and diol components should expediently be present in approximately the same molar ratios. However, if it is appropriate, for example to influence the reaction kinetics, one of the two components, preferably the diol, can also be used in excess. The excess diol is then distilled off in the course of the polycondensation.
• the polycondensation is carried out by customary methods, for example by starting from 50 mol% of the corresponding dicarboxylic acids and / or dicarboxylic acid dialkyl esters, such as the carboxylic acid dimethyl or diethyl ester, and ⁇ 50 mol% of the diol, which may initially be in In the presence of a transesterification catalyst, the mixture is heated to about 200 ° C. until sufficient methyl or ethyl alcohol has been distilled off, a low molecular weight oligo or polyester being formed. This low molecular weight ester then becomes a higher molecular weight polyester in a molten state at a reaction temperature of approx. 240-290 ° C.
• Catalysts which can be used here are the catalysts usually used for polycondensation, such as Lewis acids and bases, polyphosphoric acid, antimony trioxide, titanium tetraalkoxides, germanium tetraethoxide, organophosphates, organophosphites and mixtures thereof, a mixture of triphenyl phosphates and antimony trioxide being preferred, for example.
• the polycondensation in the melt takes less than 10 hours, preferably 2-3 hours.
• the low molecular weight ester produced in the first stage is finely pulverized or pelletized and the temperature is controlled in the range from 220 to 270 ° C. in such a way that the polyester powder or the polyester pellets never agglomerate or sinter together or even melt.
• the high molecular weight copolyester is melt-spun in a manner known per se to give the monofilaments according to the invention.
• the copolyester is dried immediately before spinning, preferably by heating in a dry atmosphere or in a vacuum.
• the core / sheath monofilaments according to the invention are used with particular advantage for or in the manufacture of textile fabrics with high mechanical and chemical resistance.
• Such a technical use of the core / sheath monofilaments according to the invention is the production of paper machine screens.
• One object of the present invention is therefore the use of the core / sheath monofilaments according to the invention for or in the production of Paper machine screens and paper machine screens which consist predominantly, ie at least 65% by weight, of the monofilaments described above, namely both paper machine long screens (forming screens) and paper machine dry screens.
• a forming fabric according to the invention in the paper machine generally has a one- to three-layer structure and has a weight per unit area of 100 to 800, preferably 200 to 600 g / m 2 .
• core / sheath monofilaments according to the invention with a diameter of 0.08 to 0.45 mm, preferably 0.13 to 0.30 mm, are used.
• Core / jacket monofilaments according to the invention with a diameter of 0.20 to 1.00 mm, preferably of 0.40 to 0.8 mm, are generally used for the production of the paper machine dryer fabrics.
• the monofilaments are woven on conventional wide weaving machines with the machine parameters common to the weaving of polyethylene terephthalate to form the paper machine screens. For example, a good screen product is obtained by weaving monofilaments with a diameter of 0.17 mm in the warp with overcuts of 0.2 mm and undercuts of 0.22 mm.
• the fabric has very good dimensional stability and excellent abrasion resistance.
• the fabric obtained is generally post-treated on a suitably dimensioned heat setting device in order to set the specific sieving properties desired in the individual case.
• the paper machine fabric produced in this way from monofilaments according to the invention has a better dimensional stability in the warp and weft directions compared to a material produced from conventional polyethylene terephthalate monofilaments and thereby causes a smoother running in the paper machine, which benefits the quality of the paper produced.
• a special embodiment of the paper machine screens are so-called spiral sieves. These sieves consist of a large number of monofilament spirals (spirals) arranged parallel to one another, the spiral spacing (pitch of the spiral) of which is at least twice the thickness of the monofilament, the spacing of the spirals lying next to one another being such that the spirals interlock.
• a plug wire (“wire” in this context means a polyester monofilament) is inserted into the cavity formed by the helix of the two interlocking spirals, whereby the adjacent spirals are connected to one another.
• a so-called cored wire can also be inserted into the cavity remaining in the center of each spiral.
• the core / sheath monofilaments according to the invention can also be used for or in the production of such spiral screens.
• Another object of the present invention is therefore the use of the core / sheath monofilaments according to the invention for or in the manufacture of spiral sieves and spiral sieves which consist predominantly, ie at least 65% by weight, of the monofilaments described above.
• core / sheath monofilaments with a diameter of 0.4 to 1.0 mm, preferably 0.5 to 0.8 mm are used to produce the spirals.
• the plug wires of these screens are expediently produced from core / sheath monofilaments according to the invention with a diameter of 0.5 to 1.5 mm, preferably 0.6 to 1.2 mm.
• Another object of the present invention is the use of the core / jacket monofilaments according to the invention described above for or in the production of screen printing fabrics and the screen printing fabrics thus obtained containing a proportion of the core / jacket monofilaments according to the invention which decisively determines its properties.
• Such a screen printing fabric generally has - depending on the diameter of the woven monofilaments - a basis weight of 10 to 200, preferably 20 to 100 g / m 2 .
• core / sheath monofilaments according to the invention with a diameter of 10 to 100 ⁇ m (corresponding to approx. 1 to 110 dtex), preferably 10 to 80 ⁇ m (corresponding to approx. 1 to 70 dtex), in particular with a diameter from 20 to 55 ⁇ m (corresponding to approx. 5 to 35 dtex).
• Particularly preferred for the production of the screen printing fabrics are core / sheath monofilaments according to the invention whose sheath and optionally also their core 0.1 to 2.0% by weight of a dye and 0.1 to 0.5% by weight of a UV -Absorbers and less than 0.3 wt .-% TiO 2 contains.
• the core / sheath monofilaments according to the invention are woven on the weaving machines customary today with the machine parameters for the screen printing fabrics which are also customary when weaving polyethylene terephthalate.
• a good screen-printed product is obtained by weaving monofilaments with a diameter of 0.040 mm in warp and weft in plain or twill weave. Because of the high modulus of elasticity of the monofilaments according to the invention, the fabric has a clearly superior, very good dimensional stability and abrasion resistance over a conventional polyester sieve, and thus a longer service life even under high stress. In many cases, the fabric according to the invention can be used to replace screen-printed fabrics which are still made from metal wire today.
• the core / sheath monofilaments according to the invention can also advantageously be used to produce mechanically and chemically outstanding stable, highly resilient and dimensionally stable conveyor belts or reinforcing inserts for conveyor belts.
• Another object of the present invention is therefore the use of the core / jacket monofilaments according to the invention for or in the production of conveyor belts and the conveyor belts thus obtained with a proportion of the core / jacket monofilaments according to the invention which significantly influences their properties.
• the copolyester obtained was cooled to room temperature and had an average molecular weight, corresponding to a specific viscosity of 0.86, measured in a 1% strength by weight solution of the polyester in dichloroacetic acid at 25 ° C.
• the polyester had a crystallite melting point of 285 ° C and a heat of fusion of 34.3 J / g, measured by D.S.C ..
• the polyester thus obtained has an average molecular weight of medium size; it serves as an intermediate for the production of a high molecular weight polyester by solid phase condensation.
• the polyester is pulverized so that it passes through a 20 mesh sieve.
• the powder is then further polycondensed under reduced pressure 24 at 220 ° C. in the solid phase until the polyester reaches an average molecular weight which corresponds to a specific viscosity of 1.37, measured under the conditions specified above.
• the crystallite melting point is then 288 ° C and the heat of fusion 62 J / g.
• the polyester thus obtained has a carboxyl end group concentration of 15 meq / kg.
• the polyester mixture prepared according to section A of this example is melted in an extruder at 300 ° C., and the melt is pressed into a spin pack by means of a metering pump. After filtration in a spin pack the melt of the mixture is fed to the peripheral jacket inlets of the said spinnerets for the production of core / jacket monofilaments.
• the polyester dried according to section B of this example is melted, filtered and fed to the central core feeds of the spinnerets.
• the melt streams were in a weight ratio of 25% by weight jacket mixture and 75% by weight core polyester at a melt temperature of 240 ° C.
• the core / sheath monofilaments obtained are then continuously drawn in two stages at 190 ° C. in the first stage and 175 ° C. in the second stage, the drawing ratio being 1: 6.0 in the first stage and 1: 1.13 in the second stage and fixed in a 4 m long channel at 215 ° C.
• a polyester of the same composition was spun in the manner described in Example 2, but with 0.334% by weight of N, N'-di-p-tolylcarbodiimide and 0.2% by weight in each case in the mixing area of the extruders, based on the respective throughput .-% 1,5-dimethylbenzene-2,4-polycarbodiimide added.
• the properties of the core / sheath monofilaments obtained in this way correspond to those of those produced in Example 2, but the resistance to hydrolysis is significantly increased.

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• Chemical & Material Sciences (AREA)
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• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Multicomponent Fibers (AREA)
• Artificial Filaments (AREA)
• Woven Fabrics (AREA)
• Paper (AREA)
• Printing Plates And Materials Therefor (AREA)
• Spinning Or Twisting Of Yarns (AREA)

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• 1995
  • 1995-03-31 DE DE19511853A patent/DE19511853A1/de not_active Withdrawn
• 1996
  • 1996-03-15 ES ES96104133T patent/ES2139971T3/es not_active Expired - Lifetime
  • 1996-03-15 DE DE59603197T patent/DE59603197D1/de not_active Expired - Fee Related
  • 1996-03-15 AT AT96104133T patent/ATE185172T1/de not_active IP Right Cessation
  • 1996-03-15 EP EP96104133A patent/EP0735165B1/fr not_active Expired - Lifetime
  • 1996-03-26 TW TW085103628A patent/TW351732B/zh active
  • 1996-03-28 MX MX9601189A patent/MX9601189A/es unknown
  • 1996-03-28 US US08/627,940 patent/US5635298A/en not_active Expired - Lifetime
  • 1996-03-29 CA CA002173039A patent/CA2173039A1/fr not_active Abandoned
  • 1996-03-29 CN CN96103948A patent/CN1068642C/zh not_active Expired - Fee Related
  • 1996-04-01 BR BR9601225A patent/BR9601225A/pt not_active Application Discontinuation
  • 1996-04-01 JP JP07896996A patent/JP3831446B2/ja not_active Expired - Fee Related

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