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
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/10—Other agents for modifying properties
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
  • D21F1/0027—Screen-cloths

Definitions

• the present invention relates to elastic threads, in particular monofilaments, with excellent resistance to hydrolysis. These are excellently suited for the production of textile fabrics which are used in applications with aggressive environments, for example in screens for paper machines.
• Threads based on thermoplastic elastomeric polyesters are generally susceptible to hydrolysis. Such threads are therefore unsuitable for applications in which hydrolytic conditions prevail, for example for use as screens in the dryer section of paper machines.
• DE 198 34 008 A1 discloses core-shell monofilaments having very good abrasion resistance.
• the sheath of these monofilaments may be constructed of conventional polyesters, but preferably of elastomeric polyesters derived from dicarboxylic acids, short-chain diols and polyglycols. It is further disclosed that carbodiimides can be used to improve the hydrolytic stability in the sheath component of these threads.
• the core may consist of copolyesters and up to at least 70% of a thermoplastic polyester and from to be constructed to 30% of a thermoplastic elastomeric polyester.
• the jacket can also be constructed from a thermoplastic polyester and from a thermoplastic elastomeric polyester.
• the polyesters of the core and of the shell can be closed by reaction with mono-, bis- and / or polycarbodiimides. The use of monomeric and polymeric carbodiimides is described by way of example.
• polycarbodiimides are preferred for some applications. These compounds are more firmly anchored in the thread due to their molecular weight and are less susceptible to diffusion to the surface and thus less likely to be extracted from the thread.
• thermoplastic elastomeric polyesters which are characterized by a very low modulus of elasticity, one would therefore expect only a small stabilizing effect when using polycarbodiimides.
• the object of the present invention is therefore to provide elastic threads and textile fabrics derived therefrom which characterized by a high hydrolytic stability.
• the invention relates to a thread containing at least 80 wt.%, Based on the mass of the or the thread-forming polymers, one or more thermoplastic elastomeric polyester and a carbodiimide having a molecular weight of at least 2000 g / mol.
• threads are generally understood to mean fibers of finite length (staple fibers), fibers of infinite length (filaments) and multifilaments composed thereof or secondary-spun yarns of staple fibers. Preference is given to melt-spun threads in the form of monofilaments.
• thermoplastic elastomeric polyesters may be compounds known to those skilled in the art under the name TPE-E.
• thermoplastic and elastomeric polyesters can be composed of a wide variety of monomer combinations. As a rule, these are blocks of so-called hard and soft segments.
• the soft segments are typically derived from polyalkylene glycol ethers.
• the hard segments are typically derived from short chain diols. In addition to the diols, the hard and soft segments are usually built up from aliphatic, cycloaliphatic and / or aromatic dicarboxylic acids.
• thermoplastic, elastomeric polyesters are polyether esters. These are preferably block copolymers comprising blocks of polyethylene terephthalate and / or polybutylene terephthalate and blocks of polyalkylene glycol terephthalate.
• thermoplastic elastomeric polyesters are understood as meaning polyesters which, at room temperature, are comparable to the conventional elastomers, but can be plastically deformed under heat supply and thus exhibit a thermoplastic behavior.
• These thermoplastic and elastomeric polyesters have in physical areas physical crosslinking points (e.g., minor valence forces or crystallites) that dissolve on heat without the polymer molecules decomposing.
• the polymer component of the threads according to the invention consists mainly of thermoplastic, elastomeric polyesters.
• the thread according to the invention may also contain small amounts of other thread-forming polymers, for example on other polyesters or on polyolefins.
• the amount of thread-forming polymer or of thread-forming polymers in the thread according to the invention is usually at least 70% by weight.
• carbodiimides are used in the thread according to the invention. These are polymeric carbodiimides which have a molecular weight of at least 2,000 g / mol, preferably at least 3,000 g / mol to 20,000 g / mmol and most preferably from 3,500 to 15,000 g / mol. It is also possible to use mixtures of polymeric carbodiimides.
• Preferably used polymeric carbodiimides have a melting range of 60 to 210 ° C.
• the polymeric carbodiimides used according to the invention are commercially available. Examples are the products R Stabaxol P from Rhein Chemie GmbH, Mannheim or carbodiimides from Raschig GmbH, Ludwigshafen.
• the proportion of polymeric carbodiimides in the thread according to the invention is generally 0.05 to 5.0 wt.%, Preferably 0.1 to 3, 0 wt.%.
• the polymeric carbodiimide is added to the thermoplastic elastomeric polyester preferably in the form of a masterbatch in the preparation of the thread according to the invention.
• the masterbatch contains, in addition to the carbodiimide, a polymer component.
• the proportion of carbodiimide in the masterbatch is usually 10 to 50 wt.%.
• the melting point of the polymer used in the masterbatch may not be above the melting point of thermoplastic, elastomeric polyester.
• suitable polymers used in the masterbatch are polyolefins, such as polyethylene or polypropylene, or in particular polyesters, very preferably thermoplastic, elastomeric polyesters.
• the threads according to the invention may contain, in addition to the thread-forming polymers and the polymeric carbodiimide, further auxiliaries or additives.
• the total proportion of these auxiliaries and additives on the thread according to the invention may be up to 25% by weight, preferably up to 10% by weight.
• auxiliaries and additives are further hydrolysis stabilizers, processing aids, antioxidants, plasticizers, lubricants, pigments, matting agents, viscosity modifiers, crystallization accelerators, UV stabilizers, flame retardant additives and / or dyes.
• hydrolysis stabilizers examples include compounds containing epoxide groups.
• 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.
• UV stabilizers examples include hindered amine light stabilizers (HALS).
• HALS hindered amine light stabilizers
• flame retardant additives are ammonium polyphosphates or melamine cyanurate.
• dyes are commercially available Renol R dyes (Clariant).
• the components required for producing the threads according to the invention are known per se, some are commercially available or can be prepared by methods known per se.
• the threads according to the invention can be in any desired form, for example as multifilaments, as staple fibers, as secondary spun yarns, also in the form of twisted yarns, or in particular as monofilaments.
• the threads according to the invention are present as single-component threads.
• the titer of the threads according to the invention can vary within wide limits. Examples are 1 to 45,000 dtex, in particular 100 to 7,000 dtex.
• the cross-sectional shape of the threads according to the invention may be arbitrary, for example round, oval or n-cornered, where n is greater than or equal to 3, or the threads have a point- or axis-symmetrical cross-section.
• the threads of the invention can be prepared by methods known per se.
• the production of the threads according to the invention can be carried out by conventional melt spinning processes, combined with single or multiple stretching and optionally fixing the threads obtained.
• the threads of the invention are characterized by a particularly good combination of elasticity and hydrolysis resistance.
• the threads of the invention are preferably used for the production of textile fabrics, in particular of woven, laid, knitted, braided or knitted fabrics.
• the fabrics are preferably used in areas where resistance to hydrolytic degradation of the polyester is required.
• the fibers of the invention can be used in all industrial fields. They are preferably used in applications in which increased wear due to mechanical stress and hydrolytic degradation of the polyester is to be expected. Examples include the use in screens, filters or in conveyor belts.
• the threads according to the invention are preferably used for the production of fabrics, in particular fabrics, which are used in screens.
• filaments of the invention in the form of monofilaments relates to their use as conveyor belts or as components of conveyor belts.
• thermoplastic, elastomeric polyetherester (Heraflex E-type, Radici / Chignolo d'Isola, Italy) and a different carbodiimide and TPE-E containing Materbatch (Rhein Chemie, Mannheim, Germany) were used.
• the masterbatch was added to the TPE-E in such an amount that the carbodiimide was introduced into the dope in the amount described below.
• the polymeric masterbatch was gravimetrically metered into the TPE-E Schnitzelstrom in the feed tube of the extruder, melted in the extruder and mixed, fed via a spinning pump to a spin pack and pressed through fine hole nozzles. Subsequently, the resulting filaments were quenched in a water bath, stretched several times under the action of temperature and wound on disc coils by means of a winding machine.
• the process conditions were chosen in all cases to achieve monofilaments of about 0.40 mm in diameter with approximately the same textile values.
• the carbodiimides used are shown in Table 1 and the process data and the resulting textile values of the monofilaments are listed in Table 2.
• Table 1 Carbodiimides used Example no. carbodiimide 1 (comparison) - 2 (comparison) Bis-carbodiimide, molecular weight 362, Stabaxol R 1 3 (according to the invention) Polym. Carbodiimide, molecular weight about 3,500, Stabaxol R KE 9514 4 (according to the invention) Polym.
• Carbodiimide molecular weight about 10,000, Stabaxol R KE 9464 example 1 Example 2 1 )
• Example 3 Example 4 Content of carbodiimide (% by weight) 0.0 1.0 1.6 1.2 Titre (dtex) 1595 - 1611 1572 Strength 2) (cN / tex) 36.9 - 34.6 37.3 rel. Elongation at 15 cN / tex 3) (%) 37.0 - 37.7 35.8 rel. Elongation at 20 cN / tex 3) (%) 3) 40.2 - 41.4 39.4 rel. Elongation at 27 cN / tex 3) (%) 44.4 - 46.6 43.9 free shrink 160 ° C / 30 min.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Textile Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Artificial Filaments (AREA)

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Citations (5)

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• 2007
  • 2007-11-24 DE DE102007056631A patent/DE102007056631A1/de not_active Withdrawn
• 2008
  • 2008-10-23 EP EP08018593A patent/EP2063003A1/fr not_active Withdrawn

Patent Citations (6)

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