Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
• • 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
  • B01D39/163—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin sintered or bonded
• • 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
• • 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
  • Y10T156/00—Adhesive bonding and miscellaneous chemical manufacture
  • Y10T156/10—Methods of surface bonding and/or assembly therefor
  • Y10T156/1002—Methods of surface bonding and/or assembly therefor with permanent bending or reshaping or surface deformation of self sustaining lamina
  • Y10T156/1043—Subsequent to assembly

Definitions

• the invention relates to impregnated filter materials which release neither during processing nor in use phenol or formaldehyde in the environment, filter elements produced therefrom and a method for producing a filter material.
• Filter materials for the automotive sector and industrial applications are usually made of cellulose and / or synthetic fibers. They are mainly used for the filtration of fuels, oils, gases, water and mixtures thereof. High demands are placed on bursting strength and rigidity in the wet and in the dry state. In addition, they should withstand harsh environmental conditions and high temperatures.
• the base material for these filters are porous webs of cellulose, glass fibers, synthetic fibers or a mixture of these. Since the selection of suitable fiber types is mainly due to the requirements of porosity, air permeability and density of the oriented filter material, the selected fiber types are usually not optimal in terms of strength.
• Phenolic resole resins or phenolic novolac resins the latter in combination with hexamethylene tetramine or other formaldehyde donors (for example salicylic, methylol-containing polymers) as curing agents, have proven useful for many years as suitable binders.
• formaldehyde donors for example salicylic, methylol-containing polymers
• Suitable solvents are lower alcohols and ketones, e.g. Methanol, ethanol, isopropanol, acetone but also water.
• partial curing of the resin occurs, which is controlled by the height of the drying temperature and the duration of the drying.
• the set degree of hardening achieves a certain initial strength of the filter material, which is necessary for its further processing. Of particular importance is the initial strength when the filter material is grooved longitudinally. It must be stiff enough that the grooving remains, but must not be too brittle, so it during further processing, eg when folding, breaks.
• the curing reaction is not easily controlled and the resin is usually over-cured.
• the filter material can thus become brittle.
• the filter material is usually embossed and folded into a bellows. Filter material that has too high a degree of cure is brittle and breaks easily during this processing step.
• the bellows are placed in a curing oven to fully cure the resin.
• the strength and rigidity required for the application is achieved both in the dry and in the wet state and the filter material is resistant to aggressive influences at high temperatures.
• significant amounts of deleterious phenol and formaldehyde are released into the environment.
• the phenol and part of the formaldehyde are contained as an impurity in the resin itself.
• most of the formaldehyde is released as a reaction product during the crosslinking reaction.
• Efforts have therefore been made in the past to replace phenolic resins with phenol and formaldehyde-free binders.
• water-based synthetic resin dispersions are increasingly being used, mostly acrylate resins. These dispersions do not inherently contain free phenol and often no bound or free formaldehyde.
• these binders need to reach the required strength and rigidity, especially when wet and resistant to aggressive influences such as hot engine oil, hardened.
• the curing takes place thermally mostly by means of reactive groups, which are located in the backbone of the synthetic resin polymers.
• a common reactive group for thermal crosslinking is N-methylolacrylamide, which, however, splits off formaldehyde during the crosslinking reaction.
• a further disadvantage of using synthetic resin dispersions as binders for filter materials is the property of these binders to form films even during drying.
• the films bridge the distances between two or more fibers and thus reduce the pore diameter and thus the permeability for the medium to be filtered.
• This negative property is all the more noticeable, the higher the binder content in the filter material.
• phenolic resins do not form films during drying due to the significantly lower chain length of their molecules and therefore do not reduce the permeability of the medium to be filtered.
• the chemical and mechanical stability of such filter media which have been impregnated with such synthetic resin dispersions are inferior and mostly unsatisfactory for applications in fuels and oils compared to phenolic resin impregnated filter media.
• Epoxy resin Another way to make a filter material that does not release any phenol and formaldehyde into the environment is the use of epoxy resin.
• Epoxy resin also contains no production of free phenol and formaldehyde. Also in the various crosslinking reactions no formaldehyde is split off and into the Environment submitted.
• epoxy resin systems have considerable disadvantages in the impregnation and subsequent drying compared to phenolic resin systems. Epoxy resins always require a hardener to cure. There are essentially two types: cold and hot curing hardeners. However, epoxy resin impregnations with exclusively cold-curing curing agents may react so quickly that the filter material is already fully cured after drying or hardened within hours at room temperature. The filter material is thus brittle and can be further processed only under difficult conditions. Embossing and folding is more difficult.
• Epoxy resin impregnations with exclusively hot curing hardeners react much slower than phenol resin systems.
• the filter medium with the epoxy resin impregnation must remain in the dryer much longer than a filter material impregnated with phenolic resin. For these reasons, Epoxidharzim Weggnierungen for filter materials are used only very rarely.
• the object of the invention is therefore to provide a filter material, in particular for motor vehicle and industrial filters, which releases no phenol and formaldehyde to the environment and the excellent properties, in particular with respect to filtration properties, resistance to aggressive influences, even at high temperatures, Has strength and rigidity in the dry and wet state and with respect to a good further processing. Furthermore, an improved filter element and an easy-to-use method for producing the filter material to be created.
• the filter material according to the invention consists of a porous, fibrous sheet material and a binder in the form of an epoxy resin impregnation, which enables a gradual hardening by a combination of a cold-curing hardener and a hot-curing hardener.
• Cold-curing here means that the curing agent begins to crosslink only from a certain temperature, which may be relatively low, but in any case is lower than in the case of the hot-curing hardener.
• the cross-linking the beginning of the cold-crosslinking curing agent can for example under 0'C, in particular between about 0 ° C and about 100 'C, are.
• the start of crosslinking of the "hot-curing" hardener is at higher temperatures, in particular at 130 ° C. or higher. Below these higher temperatures, no crosslinking takes place by the hot-curing hardener.
• phenol and formaldehyde-free substances as well as the use of hardeners, which If no formaldehyde cleavage reaction, the filter material according to the invention at no time releases phenol or formaldehyde into the environment.
• the impregnation advantageously consists of an epoxy resin having two or more epoxide groups from the series of bisphenols A and F and / or the glycidyl ethers of these bisphenols and the aliphatic epoxy resins having two or more epoxide groups. It is in lower alcohols and ketones such. As methanol, ethanol, isopropanol and acetone in any proportions soluble. At least two different types of hardener are added to the epoxy resin.
• the first type of hardener is a cold curing hardener.
• the amount added is substoichiometric with respect to the
• Epoxy resin preferably 30-80% of the stoichiometric
• Ratio and more preferably 50% of the stoichiometric ratio.
• the amount of this hardener is preferably chosen so that the filter medium according to the invention has already hardened so far after drying that it is sufficient for further processing
• the second type of hardener is a hot-curing hardener.
• the amount added is substoichiometric based on the epoxy resin, preferably 30-80% of the stoichiometric ratio and more preferably 50% of the stoichiometric ratio.
• This hardener reacts preferably from 130 "C, more preferably from 150 'C, and develops its effect only when the bellows already fully designed in the curing oven comes.
• Preferred hardeners of the first type are aliphatic hardeners (for example polyamidoamines, polyamides), modified aliphatic hardeners, cycloaliphatic amine hardeners, aromatic amines, ketimines and acid anhydrides.
• Preferred hardeners of the second type are nitrogen-containing hardeners, e.g. Dicyandiamide, guanamine, guanidine, cyanamine, triazines, triazoles, cyanamides or imidazoles.
• Particularly preferred is dicyandiamide and mixtures of dicyandiamide with promoters such as e.g. Imidazoles.
• the final curing which is essentially achieved by the second type of hardener, gives the filter medium the required strength and rigidity in the wet and in the dry state and a good resistance to aggressive influences.
• aggressive influences that act on filter materials are hot engine oil of about 150 'C or hot fuel of about 80' C. Additives in these fluids additionally increase their aggressiveness.
• the filter material according to the invention has a significantly higher resistance to hot engine oil, hot air, Ad Blue, fuels such as diesel and biodiesel and other liquid and gaseous substances to be filtered has as the phenol resin impregnated filter material.
• the porous sheet of the filter material according to the invention can be produced, for example, by the wet-laying method, the air laying method, the meltblown method or the spunbonded method. In addition, it may consist of an open-cell foam.
• the wet-laying process is understood to mean the customary process for producing papers, in which a suspension of short-cut fibers is prepared with water and this suspension, which may additionally contain the auxiliaries customary for papermaking, is spread on a wire and dehydrated. The porous fabric thus formed is then dried and wound up.
• the short cut fibers are fluidized in an air stream and also deposited on a sieve. Subsequently, the porous fabric is bonded by means of needling, water jet needle, heat application, etc. and wound up.
• thermoplastic polymer In the spunbonding process, a thermoplastic polymer is melted in an extruder and forced through a spinneret. The continuous fibers formed in the capillaries of the spinneret are drawn out of the nozzle after exiting, swirled in a storage channel and laid down in a web on a wire belt. Subsequently, the nonwoven is solidified with an embossing calender using pressure and temperature.
• thermoplastic polymer In the meltblown process, a thermoplastic polymer is melted in an extruder and forced through a spinneret.
• the in the capillaries of the spinneret formed endless fibers are stretched after emerging from the hot air nozzle and laid down in a web on a wire belt.
• Polymers for the meltblown and spunbond processes are preferably polyolefins, polyesters, polyamides, polyphenylene sulfide, polycarbonate or copolymers or mixtures thereof.
• Suitable fibers for the wet-laying and air-laying process are e.g. Cellulose, regenerated cellulose, polyester fibers, polyolefin fibers, polyamide fibers, multicomponent fibers, glass fibers, carbon fibers.
• the filter materials according to the invention typically have a basis weight according to DIN EN ISO 536 of 10 to 400 g / m 2 , an air permeability according to DIN EN ISO 9237 of 2 to 10,000 l / m 2 s and a thickness to DIN EN ISO 534 of 0 , 1 - 5.0 mm.
• the filter material according to the invention may be both single-layer and multi-layer, wherein at least one layer is treated with the Epoxidharzim Weggntechnik invention.
• Paper with a basis weight of 100 g / m 2 and an air permeability of 860 l / m 2 s was prepared on a Schrägsiebpapiermaschine, impregnated on the laboratory foulard and dried in a convection oven for 15 min at 80 'C. The impregnation was carried out with a mixture of
• the content of impregnating agent was 19% by weight, based on the weight per unit area of the impregnated medium.
• the bursting strength, the air permeability, the basis weight, the bending stiffness wet longitudinally, the bending stiffness dry longitudinally, the re-drying behavior, the hot oil resistance, the Nachverzu constituents and the phenol and Formaldehydemission were then measured on this medium. The results are shown in Table 1.
• Paper from Example 1 was impregnated under the same conditions as in Example 1 with a standard phenolic resin of the following recipe:
• the content of impregnating agent was 19% by weight, based on the area-related mass of the impregnated medium.
• the bursting strength, the air permeability, the basis weight, the bending stiffness wet longitudinally, the bending stiffness dry longitudinally, the re-drying behavior, the hot oil resistance, the Nachverzu constituents and the phenol and Formaldehydemission were then measured on this medium. The results are shown in Table 1.
• the filter material is cured in a convection oven at 165 ° C. for 10 minutes, then the hardened, flat filter material is stored for 3 weeks at 150 ° C. in the Shell Helix Ultra 5W30 motor oil and then for a further 24 hours in standard climate according to DIN EN ISO 20187 conditioned. Finally, the bursting strength according to DIN EN ISO 2758 is determined on the aged filter material and compared with the bursting strength of the non-aged filter material.
• the sample to be tested is stored for 24 hours at 160 'C in a convection oven. After air conditioning according to DIN EN ISO 20187, the bursting strength is determined according to DIN EN ISO 2758. Dries behavior
• the air permeability according to DIN EN ISO 9237 is determined on the air-conditioned sample according to DIN EN ISO 20187.
• the sample is then placed in distilled water for 10 minutes and then quenched between two blotting boxes for 5 seconds.
• the differential pressure is maintained at 200 Pa.
• read off the air permeability value is Immediately after inserting the sample into the instrument and every 30 seconds.
• Example 1 is significantly better than the previously used phenolic resin-impregnated filter material (Comparative Example). Only the bending stiffness wet longitudinally is slightly lower in the filter material according to the invention, but is still in the usual range for these filter materials.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Filtering Materials (AREA)
• Epoxy Resins (AREA)
• Adhesives Or Adhesive Processes (AREA)

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• 2009
  • 2009-01-29 DE DE102009006584A patent/DE102009006584B4/de not_active Expired - Fee Related
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