Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/14—Other self-supporting filtering material ; Other filtering material
  • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
  • B01D39/1607—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
  • B01D39/1615—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of natural origin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/14—Other self-supporting filtering material ; Other filtering material
  • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
  • B01D39/1607—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
  • B01D39/1623—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
• • 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
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
  • Y10T442/637—Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material
• • 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
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
  • Y10T442/659—Including an additional nonwoven fabric
  • Y10T442/668—Separate nonwoven fabric layers comprise chemically different strand or fiber material
• • 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
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
  • Y10T442/681—Spun-bonded nonwoven fabric

Definitions

• the present invention relates to a heat sealable filter material with excellent hot water resistance and biodegradability, which contains fibers made of a heat sealable, biodegradable and compostable material and a lubricant.
• bags that are brewed for use with hot water.
• These bags usually consist of a first layer of a porous material made of natural fibers and a second layer of hot-melting polymer fibers such as PP, PE or various copolymers. This second layer is used to close the bag by heat sealing on tendon-wrapping machines.
• This bag material can be produced in a known manner according to a wet-laid process on a paper machine, a dry-laid process on a fleece laying machine or a melt-blown process by depositing polymer aers on a carrier layer ⁇ L- ⁇
• the used filter bags are disposed of on a compost heap or via the organic waste bin. After a certain period of time, which depends on other parameters such as temperature, humidity, microorganisms etc., the natural fiber component of the filter bag has disintegrated and biodegraded, while the thermoplastic polymer fiber network is preserved and the quality of the composite is reduced.
• EP-A-0 380 127 describes a heat-sealable tea bag paper with a basis weight of 10-15 g / m 2 , which is provided with polymers such as PP, P ⁇ or a copolymer for heat sealing and is therefore not biodegradable.
• EP-A-0 656 224 describes a filter material, in particular for the production of tea bags and coffee bags or filters with a basis weight between 8 and 40 g / m 2 , in which the heat-sealable layer consists of plastic fibers, preferably of polypropylene or Polyethylene, which is placed in a softened state on the first layer made of natural fibers.
• JP-A-2001-131826 describes the production of biodegradable monofilaments from poly-L-lactide and the subsequent production of fully synthetic tea bags woven therefrom using a dry-laid process.
• German patent application DE-A 21 47 321 describes a thermoplastic, heat-sealable composition which consists of a polyolefin powder (polyethylene or polypropylene) which is embedded in a carrier matrix made of vinyl chloride / vinyl acetate copolymer. This material is also used for the heat-sealable finishing of paper-based fiber material.
• DE-A-197 19 807 describes a biodegradable heat-sealable filter material that consists of at least one layer of natural fibers and at least a second layer of heat-sealable synthetic material that is biodegradable.
• This filter material is obtained by applying on a wire in a first step as aqueous suspension, the natural fibers and the heat-sealable, biodegradable polymer fibers are deposited on the natural fiber layer ⁇ such in a second stage that they can penetrate the natural fiber layer partially.
• the used filter materials such as Tea bags, coffee bags or other filters are often disposed of in a compost heap or in the organic waste bin. After a certain period of time, which depends on other parameters such as temperature, air humidity, microorganisms, etc., the natural fiber component of the filter has disintegrated and biodegraded, while the thermoplastic polymer fiber network of polymer fibers that are not completely biodegradable is retained and the quality of the compost is reduced.
• So-called heat-sealing rollers generally seal the bag at a temperature of 150-230 ° C in a cycle time of less than 1 second. With these short cycle times, the heat-sealing material must melt, adhere to one another and immediately solidify and crystallize again so that the bag is closed again during further transport and no filling material can escape.
• the present invention relates to a filter material which contains fibers from a heat-sealable, biodegradable and compostable material and is characterized in that it additionally contains a lubricant in an amount of 0.5 to 5.0% by weight, based on the weight of the paper of the finished filter material.
• thermoplastic material according to the invention the property that, using the filter material according to the invention (as described above), heat-sealing seams formed with the aid of a heat-sealing roller are extremely stable in hot water.
• hot water stable here means according to the invention a resistance or integrity of a heat seal seam of a filter bag made from the filter material according to the invention during the brewing process for 4 minutes.
• the filter material according to the invention can be heat-sealed by ultrasound treatment.
• biodegradable and compostable polymer fibers that are used according to the invention, we mean completely biodegradable and compostable polymer fibers according to DIN 54900.
• the lubricants which can be used according to the invention are compounds which lead to better sliding behavior of the polymer fibers and thus support and improve the gathering and the orientation of crystalline zones. This increases the proportion of crystalline zones in the polymer fibers.
• Such lubricants are well known to those skilled in the art. It can be hydrocarbon oils or waxes or silicone oils.
• the lubricants which can be used according to the invention consist of fatty acid esters of long-chain fatty acids with a chain length of 10 to 40 carbon atoms, for example around a fatty acid ester sold by Henkel with the name Loxiol.
• the lubricant is preferably present in the filter material according to the invention in an amount of 1.0 to 3.0% by weight.
• the inventors of the present invention currently assume that the use of a lubricant promotes rapid recrystallization of the polymer fibers, which is particularly necessary and helpful for the heat-sealing strength, so that neighboring fibers in the fabric close as quickly as possible find comparable crystallization zones, which then become more pronounced.
• the filter material according to the invention further contains a seed material which supports the crystallization of the fibers from the heat-sealable, biodegradable and compostable material during the heat sealing.
• inorganic materials such as talc, kaolin or similar materials are suitable as the seed material, usually in finely divided form.
• the particle size of the seed material is usually 0.1 to 5 ⁇ m.
• the amount of the seed material added is usually 0.01 to 1.0% by weight.
• the starting materials for the fibers made of the heat-sealable, biodegradable and compostable material are fibers made of polymers which are selected from the group of aluminum phatic or partially aromatic polyester amides and aliphatic or partially aromatic polyesters are selected.
• aromatic acids making up no more than 50% by weight, based on all acids.
• Aliphatic or partially aromatic polyester amides C) from aliphatic bifunctional alcohols, preferably linear C 2 to C 10 dialcohols such as ethanediol, butanediol, hexanediol or particularly preferably butanediol and / or optionally cycloaliphatic bifunctional alcohols, preferably having 5 to 8 carbon atoms in the cycloaliphatic ring , such as cyclohexanedimethanol, and / or partially or completely instead of the diols, monomeric or oligomeric polyols based on ethylene glycol, propylene glycol, tetrahydrofuran or copolymers thereof with molecular weights of up to 4000, preferably up to 1000, and / or possibly low Amounts of branched bifunctional alcohols, preferably with C 2 -C 12 alkyl dicarboxylic acids, such as neopentyl glycol and, if appropriate, small amounts of
• aromatic acids making up no more than 50% by weight, based on all acids
• the ester fraction C) and / or D) is at least 20% by weight, based on the sum of C), D), E) and F), preferably the weight fraction of the ester structures is 20 to 80% by weight, the fraction of Amide structures is 80 to 20% by weight.
• the synthesis of the biodegradable and compostable polyester amides used according to the invention can be carried out either by the "polyamide method” by stoichiometric mixing of the starting components, if appropriate with the addition of water and subsequent removal of water from the reaction mixture, or by the “polyester method” by stoichiometric mixing of the Starting components and addition of an excess of diol with esterification of the acid groups and subsequent transesterification or transamidation of these esters. In this second case, the excess diol is distilled off in addition to water.
• the synthesis according to the described "polyester method” is preferred.
• the polycondensation can be further accelerated by using known catalysts. Both the known phosphorus compounds, which accelerate polyamide synthesis, and acidic or organometallic catalysts for the esterification, as well as combinations of the two, are possible for accelerating the polycondensation. Care must be taken to ensure that the catalysts used, if any, do not have a negative effect on the biodegradability or compostability or the quality of the resulting compost.
• polycondensation to polyesteramides can be influenced by the use of lysine, lysine derivatives or other amidically branching products such as, for example, aminoethylaminoethanol, which both accelerate the condensation and lead to branched products (see, for example, EP-A-0 641 817; DE -A-38 31 709).
• polyesters are generally known or is carried out analogously by known processes (cf. e.g. EP-A-0 592 975).
• the polyesters or polyester amides used according to the invention may further contain 0.1 to 5% by weight, preferably 0.1 to 3% by weight, in particular 0.1 to 1% by weight, of additives, based on the polymer ( see also description of the polymers).
• additives are modifiers and / or fillers and reinforcing materials and / or processing aids such as, for example, nucleating aids, customary plasticizers, mold release aids, flame retardants, impact modifiers, colorants, stabilizers and other additives customary in the field of thermoplastics, with a view to the requirement of Biodegradability, care must be taken to ensure that the compostability is not impaired by the additives and that the additives remaining in the compost are harmless.
• the biodegradable and compostable polyesters and polyester amides generally have a molecular weight of 5,000 to 500,000 g / mol, advantageously 5,000 to 350,000 g / mol, preferably 10,000 to 250,000 g / mol, determined by gel chromatography (GPC), for example in m Cresol against a polystyrene standard.
• GPC gel chromatography
• the biodegradable and compostable polymers preferably have a statistical distribution of the starting monomers .
• the fibers in the heatsealable, biodegradable and compostable Material around stretched, heat sealable, biodegradable and compostable polymer fibers are stretched, heat sealable, biodegradable and compostable polymer fibers.
• heat-sealable, biodegradable and compostable polymeric fibers usually have a linear density (DIN 1301, TI) of 0.1 to 10 dtex, preferably 1.0 to 6 dtex.
• these are usually in an amount of 0.05 to 50% by weight, based on the paper weight of the finished filter material, advantageously in an amount of 0.1 to 45% by weight and preferably in an amount of 1 , 0 to 35% by weight.
• the stretched, heat-sealable, biodegradable and compostable polymer fibers which can be used according to the invention usually have a stretching ratio of 1.2 to 8, preferably 2 to 6.
• the crystallization of the polymer fibers induced by this stretching increases the resistance of these fibers after the heat sealing to boiling water.
• the draw ratio was determined according to the invention in a manner generally known to the person skilled in the art in the relevant field.
• the stretching ratio required according to the invention can be set in the production of the polymer fibers which can be used according to the invention by producing the polymer fibers by a melt spinning process on commercially available spinning systems in such a way that polymer fibers having a stretching ratio of 1.2 to 8, preferably 2 to 6, are obtained.
• the following parameters have proven to be favorable process parameters for the production of preferred stretched polymer fibers which can be used according to the invention:
• Spinning temperature 180 to 250 ° C, preferably 190 to 240 ° C;
• Cooling air temperature 10 to 60 ° C, preferably 20 to 50 ° C;
• - Hot drawing at 85 to 180 ° C, preferably 120 to 160 ° C.
• a hydrophilic substance is also used in the drawing of the polymer fibers in order to improve the water absorption due to their wetting properties.
• the polymer fibers are drawn after drawing, i.e. after receipt on the spinning system, further thermally fixed. This serves to minimize shrinkage of the stretched polymer fibers.
• This thermal fixation is usually carried out by thermal treatment of the stretched polymer fibers at temperatures from 10 to 40 ° C. below the respective melting point of the polymer fibers.
• the stretched polymer fibers obtained are furthermore usually cut to a length of 1 to 20 mm, advantageously 1 to 10 mm and preferably 2 to 6 mm before incorporation of the stretched polymer fibers in the course of the filter material production process.
• This cutting of the polymer fibers obtained is usually carried out with commercially available cutting tools for filaments.
• the filter material according to the invention can be heat-sealed by ultrasound treatment.
• the starting materials for the drawn polymer fibers are polyester amides with an ester content of 40 to 65% by weight and an amide content of 35 to 60% by weight, for example a polyester amide from AH salt, adipic acid , Butanediol with an amide content of 60% by weight and an ester content of 40% by weight and a mass-average molecular weight of 19,300 (determined by means of GPC in m-cresol against polystyrene standard).
• the starting materials used for the stretched polymer fibers are those with a moisture content of 0.1% by weight or less, based on the starting material polymer, preferably those with a moisture content of 0.01% by weight or less to prevent disturbances when spinning and stretching the polymer fibers.
• the filter materials according to the invention contain Ren material natural fibers and / or cellulose derivative fibers in an amount of 50 to 99.95 wt .-%, based on the paper weight of the finished filter material, advantageously in an amount of 65 to 99.9 wt .-% and preferably in an amount of 80 up to 99.5% by weight.
• the natural fibers which can be used according to the invention are the natural fibers known to the person skilled in the relevant art, such as hemp, manila, jute ' , sisal and others, and long-fiber wood pulp.
• the filter materials according to the invention comprise at least one further component which comprises or preferably consists of natural fibers.
• the filter material according to the invention is thus produced from two or more layers of different components, at least one layer containing natural fibers and one layer containing a fiber blend of fibers made from a heat-sealable, biodegradable and compostable material and lubricant, that the at least two layers can partially penetrate one another after the filter material has been produced.
• the degree of penetration of the layers can be controlled by the manufacturing process of the filter material, for example in the case of using a paper machine by adjusting the degree of dewatering on the screen.
• the second layer usually comprises a fiber blend made of natural fibers, fibers made of a heat-sealable, biodegradable and compostable material and lubricants. This can be placed on the paper machine on the first layer made of natural fibers and can be fused to one another as well as to the paper layer.
• the second layer usually comprises a fiber blend of fibers made from a heat-sealable, biodegradable and compostable material and lubricant. This can be deposited on the first layer of natural fibers using the meltblown method and can be fused both to one another and to the paper layer.
• the first layer of the filter material generally has a basis weight between 8 and 40 g / m 2 , preferably from 10 to 20 g / m 2 and an air permeability of 300 to 4000 l / m 2 "s (DIN ISO 9237), preferably of 500 up to 3000 l / m 2 »s.
• the second layer of filter material generally has a weight per unit area between 1 and 15 g / m 2 , preferably between 1.5 and 10 g / m 2 .
• the first layer of the filter material with or preferably made of natural fibers is preferably designed to be wet-strength.
• Known natural fibers such as hemp, manila, jute, sisal and other long-fiber wood pulps and mixtures thereof are preferably used for the first layer with or preferably made of natural fibers.
• the second layer can contain the mixture of fibers from a heat-sealable, biodegradable and compostable material and lubricant, and consist of them.
• the second layer preferably comprises, in addition to the above components, a further component, in particular natural fibers, with mixing ratios of 1/3 natural fibers and 2/3 mixture of cellulose derivative and polymer fibers being particularly preferred.
• the filter material according to the invention can be used, for example, for the production of tea bags, coffee bags or tea or coffee filters.
• the method for producing the filter materials according to the invention can be controlled in such a way that the biodegradable and compostable heat-sealable fibers of the partially penetrate the first layer and envelop the fibers of the first layer, preferably the natural fibers of the first layer, thus in the molten state during the drying process, for example on the paper machine.
• the pores necessary for filtration are left free.
• FIG 1 shows.
• Fig. 1 the formation of the filter material according to the invention is shown in a schematic representation.
• La) shows the formation of a first fiber layer from natural fibers 1 and the formation of a second fiber layer with synthetic, biodegradable and compostable heat-sealable fibers 2.
• the formation of the second layer with the fibers 2 thus takes place by deposition over the first layer, which is formed by the natural fibers 1.
• the natural fibers 1 are hatched horizontally to distinguish them, while the heat-sealable fibers 2 have been hatched approximately vertically.
• Fig. Lb shows how a partial penetration of the two layers is achieved by the described dewatering of the two layers, in particular the second layer with the fibers 2, so that the synthetic fibers 2 get between the natural fibers 1.
• the partially penetrating layers 1 and 2 are dried and heated in such a way that the synthetic fibers 2 melt and, during re-consolidation, lay around the fibers 1 in such a way that they are at least partially covered.
• the filter material has thus become heat sealable (Fig. Lc).
• Fig. 2 shows the basic structure of a paper machine, as used for producing a filter material according to the invention can be.
• a suspension "A” is formed from the ground natural fibers and water.
• the fiber blend is used to produce a suspension "B” from fibers from a heat-sealable, biodegradable and compostable material and lubricant and, if appropriate, a proportion of other fibers, for example natural fibers, and water.
• the suspension 'A is passed onto the screen 5, via the first two dewatering chambers 6, via suitable pipelines and pumping devices, which are not shown in more detail, the water being sucked off through the chambers 6 and the dewatering line.
• a first fiber layer of natural fibers 1 is formed on the moving sieve 5.
• the second suspension B is supplied, the second layer of synthetic fibers being deposited over the dewatering chambers 7 on the first layer , The drainage takes place via the drainage line.
• dewatering is carried out via the dewatering chambers 8, as a result of which the two layers partially penetrate one another. By setting the drainage accordingly, the penetration can be more or less strong.
• the material 9 now formed from natural fibers and polymer fibers is removed from the sieve and fed to drying.
• This drying can be done in different ways, e.g. B. by contact drying or fürströmmedrock ⁇ ung.
• the elements 10 only give a rough schematic indication of corresponding drying elements.
• drying cylinders 10 are drawn, over which the shaped paper web is dried in the contact process.
• the heating of the two-layer fiber material causes the synthetic fibers 2 in the mixed layer 9 to melt.
• the synthetic fibers at least partially envelop the natural fibers and the heat-sealable filter material is rolled up on a roll 11.
• biodegradable and compostable filter material according to the invention can also be produced by the meltblown process, as described below for a two-layer filter material:
• the mixture of biodegradable and compostable polymer and lubricant which forms the second layer is in the form of granules, it can be shaped into fibers using the melt-blown (meltblown fibers) process and in the hot-hot adhesive state on a base, e.g. B. a paper made of natural fibers.
• a base e.g. B. a paper made of natural fibers.
• the dried granulate 12 is transported to an extruder 13, in which it is melted and heated to the temperature required for fiber formation.
• This molten and heated mixture then reaches the MB nozzle 14.
• This nozzle has a large number of small openings through which the molten polymer mixture is pressed and drawn into fibers.
• These fibers 15 are captured directly below this nozzle by a strong air stream, stretched further, torn into different lengths and placed on a base, e.g. B. a paper made of natural fibers 16, which lies on a suction roller 17, filed. Since these fibers are still hot and sticky, they stick to the natural fibers of the paper.
• the material is then rolled up on the winder 18 in the cooled state.
• the typical diameter of these meltblown fibers is between 2 and 7 ⁇ m. 3 is a schematic representation of the meltblown process.
• Example 1 is a schematic representation of the meltblown process.
• a single-layer, approx. 13 g / m 2 filter material made of natural fibers was produced on the paper machine using the wet laying process. (Mixture of 35% by weight of manila fibers and 65% by weight of softwood pulp). The filter material was made wet-proof.
• Tea bags were handmade from this 2-layer filter material and filled with 1.9 g of tea. These manufactured tea bags were then sealed on all four sides with a commercially available sealing device from RDM type HSE-3. Parameters: temperature: 210 ° C
• Infusion test Three arbitrarily selected tea bags made according to the above description were poured with boiling water and allowed to steep for 4 minutes.
• a filter material was produced according to the above information, but instead of the biodegradable heat-sealable polymer fibers, a non-biodegradable vinyl chloride / vinyl acetate copolymer was used.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Filtering Materials (AREA)
• Biological Depolymerization Polymers (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Nonwoven Fabrics (AREA)

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• 2002
  • 2002-02-19 DE DE2002106924 patent/DE10206924B4/de not_active Expired - Fee Related
• 2003
  • 2003-02-19 EP EP03742544A patent/EP1476241A2/de not_active Withdrawn
  • 2003-02-19 WO PCT/EP2003/001672 patent/WO2003070353A2/de active Application Filing
  • 2003-02-19 CN CNA03800075XA patent/CN1533343A/zh active Pending
  • 2003-02-19 JP JP2003569305A patent/JP4571411B2/ja not_active Expired - Fee Related
  • 2003-02-19 US US10/472,086 patent/US7344034B2/en not_active Expired - Fee Related
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  • 2003-02-19 CA CA 2435578 patent/CA2435578A1/en not_active Abandoned
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  • 2008-01-21 US US12/017,150 patent/US7905985B2/en not_active Expired - Fee Related
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