MXPA97003863A - Binding composition for fibrous band production and a procedure to produce fibred band articles - Google Patents

Abstract

The present invention relates to: A process and a binder for producing fibrous webs and fibrous web molded articles preferably in tools for molding, wherein the fibrous webs are chemically bonded with powder binders consisting entirely or partially of coating material in powder, preferably recirculated powder coating material

Description

BINDING COMPOSITION FOR THE PRODUCTION OF FIBROUS BANDS AND A PROCEDURE TO PRODUCE BAND MOLDED ARTICLES FIBROSA FIELD OF THE INVENTION J This invention relates to a special binder mixture for producing fibrous webs, and to the use of this binder mixture. Also disclosed are methods for producing ribose bands and fibrous web molded articles that are join «μjirní carnen + o with agluti before.

BACKGROUND OF THE INVENTION In the industry, articles are widely used moldings based on fibrous bands. This comprises felt made of fibers of different sizes that can be mixed with lutin ni. Uninore products, called pre-treated cloths (chemically bonded fibrous bands) can be produced from these fibrous webs, and then molded, cured and optionally trimmed to the appropriate size using the corresponding tools in treatment . It is also possible to produce corresponding products with fibrous strip facts directly from the fibers and binding powders. These molded articles ' > > '- or flat items have a wide range of uses. For example, in the automotive industry, these products are used as molded articles, for example, as an insulating material for machine compartments or wheel protections, or as insulation of the large patch pack. Another area of use is its use as flat items, for example, as insulating material in washing machines, canvas dryers or loudspeakers, in sound absorbing walls. They can be provided with additional coatings, for example lining, covering or lamination. These molded items or flat deliveries that are provided in this way with a The stable and decorative surface covering can then be used, for example, as interior door finishes, cup zippers or roof linings in the automotive industry. It is understood that a fibrous web material is a Bonded textile material produced by the consolidation of fibrous web, particularly spun bonded web (for example parallel, crushed or fitted fibrous web); by a wet or dry route. In the course of this procedure, it is mechanically consolidated (eg felt) ? 0 chipping) or the way of making paper with the help of cellulose fibers, or chemically by bonding with adhesive, sticking or dissolving, the present invention refers to the last mentioned case, in which a binder for the chemical consolidation of the fibrous band. ? The methods of producing fibrous webs and mixing these webs with agglutinated powders are known. In the course of these methods, the fibrous material is ovenified, for example in a fiber mixing chamber, and deposited on a conveyor belt or a loose fibrous layer. Thereafter, the binder mixture is applied to the fibrous material, for example by means of dosing rollers or vibrating channels, and is mixed homogeneously, the homogeneous mixture of fiber and binder powder is deposited to form a continuous fibrous web. The components of this mixture 0 can be adhesively bonded together by means of light heating and subsequent cooling, whereby pre-impregnated fibers are formed, or pianos or cylinders which are already fully cured can be produced. The pre-impregnated fibers are not finally cured, but they are stable in storage. After treating them to their final shape, these pre-impregnated fibers are thermally entangled under the action of heat- at temperatures of up to 210 ° C, whereby thermoformed plastic molded articles are obtained from the materials. In many cases, phenolic resins are used here as binders in many cases. r, e use fibrous webs and fibrous strip molded articles in many areas of daily life, and they are also used in the automotive industry in "> par + icular. Difficulties may arise during use, since phenolic resins contain the chemical compound hexarnet i lentet r ariu na, abbreviated as hexa, as a purified component, which can result in an annoying odor If an insufficient reaction takes place, the object of the present invention is to provide a binder mixture and a process for producing fibrous web molded articles in which the PU resins which are normally used can be replaced with other components that give as a result. The result is stable, reactive binder mixtures, which are suitable for the production of pre-impregnated fibrous webs or cured fi-band articles.An additional object is to reduce the content of harmful substances to health.These binder mixtures must meet the normal requirements for the production of molded articles of fibrous web and thus should increase the stable molded articles cured that can be adapted for different application purposes. Another object is the development of a process for producing fibrous web molded articles with these mixed agglutination blends. It has been shown that this object can be achieved with the use of powder coating waste materials or powder binders. for the production of molded articles from fibrous webs. In particular, it has surprisingly been found that a considerable part of at least one of the resins ue < or used normally, it can be replaced with powder disposal materials.

The present invention relates to a mixture for producing articles molded from fibrous webs, comprising a) from 20 to 45% by weight of a binder mixture in powder form, b) from BO to 55% by weight of organic fibers and or inorganic, which are characterized in that the binder mixture in powder contains ai) from 0 to less than 10% by weight of phenol resin, preferably powdered ream, and 2) from 100 to 70% by weight. Weight of powder coating waste materials. The present invention also relates to the use of powder coating waste materials to produce molded articles containing fibrous web. The invention relates to processes for producing articles molded from fibrous webs and these binder mixtures. In the lacquer industry, the powder is increasingly being used.This has the advantage that a solvent-free application procedure is possible. However, the application procedures for powder coatings have the disadvantage that a suitable proportion of the powder does not reach the nb "je". or to be coated. These powders are collected in the spray coating booth in what is called overspray. The powders are sensitive with respect to their particle size and purity distribution. Therefore, this overspill has to be discarded as waste material. In the last stage of production of powder coating, the shredded powder coating materials, ext noises, are subjected to grinding. Fine powder is produced during this milling operation, which has an adverse effect on the coating process. Therefore, this powder is substantially eliminated. The powder can only be recirculated with difficulty and must be disposed of as a waste. The fibers used for the different fibrous webs comprise woven, felt or mixed fibers. The fibers consist of known materials, for example natural, organic and organic fibers. Examples thereof include glass fibers, mineral wool fibers, polyester fibers, acrylic resin fibers, polyolefin fibers, wool fibers, cotton fibers, flax fibers or the like. Preferably, textile fibers are used, particularly cotton fibers, for example fibrous waste materials from the textile industry. These fibers or fibrous webs made of pot are known in the industry. Also known are the procedures by which they can be produced. The production can be effected by e lim i, by means of ejido or felt formation. The resulting fibrous bands must be substantially dry; optionally, they can be impregnated with additive. Examples of the phenol resins which can be used in the mixtures according to the invention include the common reactive phenolic reams already known in the industpa. These may be reactive powdered phenolic resins containing non-crosslinked OH groups, for example. Resins of this type are already used for the production of mounds from fibrous bands, for example, they can be used Phenol resins based on phenol and formaldehyde, such as those known as resoles or novolacs. These resins may contain a formaldehyde condensation product as possible crosslinking agents. These resins have already been widely described in the literature, for example by R "N. Shreeve, in "The Chemical Process Industries", Plastics chapter, 1945, and are available eornercialrnonte. Further phenolic resins are also described in DE-A-38 33 656, EP-FL-0 363 539 and in EP-FL-0 V6 432. Phenolic resins of the 0 type de novo lac are particularly pre-charged. of phenol resins is determined by the type and amount of interlacing agent used.An inverse reaction will generally be between 120 ° C and 222 ° C. powder form Suitable particle sizes are between 0.1 and 500 μm, for example, preferably between 2 and 150 μm, preferably between 10 and 60 μm .. Particle sizes of the used powder coating waste materials fall within the same scale as those of the resins, for example, and are preferably between l and 300 μm, and preferably between 10 and 60 μrn.If powder coating materials are used, the particle sizes of which are too small for the desired purpose of application, it is possible or To obtain larger particle sizes by agglomeration of the particles. The powder coating waste materials that can be used according to the invention are those obtained from commonly known powder coatings. The binders of these powder coatings may be based on epoxy resin, polyester resins, polyurethane resins or acrylic resins, for example. These powder coating waste materials arise, for example, from the evaporation of spray booths or as defective batches during the production of powder coatings. It is also possible to collect and use filter dust, and residues from the grinding of the powders. The powder coating waste materials which may be used in the mixture according to the invention are not yet in recrystallized. They may contain reactive groups, such as oarboxyl groups, epoxide groups, hydroxyl groups, arnino groups, amide groups or isocyanate derivatives. , for example. These are able to react to each other by heating. The temperature of entrocruzarniento depends on its structure of basic skeleton. It is usually between 120 and 220 ° C. Powder coating materials with recharge temperatures above 130 ° C are used only in small quantities, so that the reclosing of the binder mixture used is as complete as possible, even at curing temperatures. for molded articles of approximately L60 ° C In addition, at high recycling temperatures, particularly when fibrous webs are used that contain plastic fibers, there is a risk that the fibers will degrade, which results in a reduction in the stability of the molding. The reclosing temperatures of the powder coating are proformably less than L60 ° C. The powder coatings used are known systems of binder vehicle. They include the usual resins, for example that! r, a tuse < ? e ov do, p l liter, urethane or acplate. The epoxy powder coatings contain epoxy reams, although their main binder component. These are often cross-linked using curing agents containing hydroxyl groups, or amide or amine groups in the range Lar. In addition, LO powder coatings are known. poly ester in which the main binder component comprises polymers containing carboxyl groups. Reagent agents containing epoxide groups, or recruiting agents containing mino or amide groups, are known as cross-linking agents which are present in proportions, for example. In this regard, it is customary for agents of ent recceza ient o used in each case to be of greater functionality than the main binder component. If epoxy do / pol mixtures are used? s <; er, which are called hybrid systems, are present approximately equal quantitative relationships of polyesters and epoxy resins, respectively. The powder coatings of poly ur-ethane are based on polyesters containing hydroxyl groups, which are capable of crosslinking by reversibly blocked polyisocyanates which are protected with known blocking agents such as caprolact amas or cetoxirna, for example, or which exists as uretdione. The acrylic powder types are generally mixtures of two or more acrylic resins each containing functional groups such as epoxide groups, carboxyl groups, hydroxyl groups or isooianate groups. the groups that react with each other are distributed among different molecules here. These binder vehicle powders are described, for example, in .T. Harps, in "The Technology of Powder Coatmgs", 1976, and by D.A. Bate in "The Science of Powder Coatings", Vol., 1990. Colorless or pigmented powder coating materials can be used, whereby it is possible to employ the usual inorganic or organic coloring pigments known as pigments. It is also possible to incorporate effect pigments, for example, metallic pigments, into the powders. Separation is not necessary according to color. The grain fineness of the powder is not important; simply make sure in general that an average sample of the different dust residues are used for the production of the binder mixture. This results in improved mixing behavior and improvements in the production constancy of the binder mixture. Any powder coating can be used in the binder mixtures. If only small proportions of phenolic resins are mixed with the mixtures (less than 5%), powder coating materials which coinpiped a higher density of ont recruz > rn? ent o. The use of epoxy powders, polyester powders or mixtures thereof as in a2 is preferred. In this regard, optionally up to 60 wt.% Of 2, preferably up to 30 wt.%, May be optionally replaced by poly-ur-ethane powder and / or polyacrylate powder. A particularly preferred embodiment makes use of a mixture of ->? Ox powders? or and polioster powders as in a2. In this regard, it is possible to produce an L2 mix directly, within the desired weight ratios, and save it, or if it is possible to produce this from the individual components by mixing them directly before further processing. The individual chemical types of materials are mixed homogeneously so that a sample that becomes uniformly mixed with respect to particle size distribution, composition and pigmentation. The density of the recrossing or the reactivity of the binder mixture can optionally be influenced by the addition of additional crosslinking constituents. A preferred embodiment employs a mixture of powder reverse resins without additional phenolic resins. In this regard, the powder coating waste materials or powder coating materials can be mixed. An advantageous particle size distribution can optionally be achieved by means of additional trituration or by agglomeration of very fine powder coating constituent. The particle size can preferably be of the order of the mentioned magnitude for phenol resins i c s. Optional additives or adjuvants may be added optionally together with the powders. Examples of the misinos may include catalysts, accelerator or flame retardants. They are preferably used as catalyst compounds of e-ao such as dibutii tin dilaurate, carboxylic acid salts such as lithium benzoate, quaternary ammonium compounds such as tet ramet ilamomo bromide, cyti bromide 11 r net ilarnomo, Fertile bromide, ryrnethylammonium, or triemethylamine chloride, or tertiary amines such as rusopropy, Lamin, or methylimidazole. Examples of suitable accelerators and crosslinking agents include basic compounds containing epoxide groups, such as t rigidylcyanates, glycoliols, di-cyanodi-a or beta-hydroxylamides. These additives can be added separately as pulverized substances. They can also be introduced mixed with binding constituents as a master filler, or they can be added as a mixture with ai binder powder. It is also possible to introduce flame retardant substances. These comprise the usual known substances contained in flame retardant coatings. Examples of compounds such as these include borates such as sodium borate, such phosphates or ammonium phosphate or sodium phosphate, or aluminum hydroxides or oxides. Others of metal oxide compounds include compounds that contain heavy metals such as tin oxide compounds, or per-brominated or perchlorinated compounds, such as phenol oxide. However, flame retardant substances which are free of heavy metals and halogens should preferably be used. These flame retardant substances require dust. They can be introduced by means of a separate masterpiece or they can be added by means of binding powders of i or a, as a homogeneous sample with the powder component in each satin. Pigments can also be introduced into the binder mixture of a). It is generally preferable not to introduce additional pigments, however, if or only the fibrous webs of the fibrous webs or the pigments contained in a2 powder coating materials. The impregnated fibers formed before curing, or the finished molding, generally contain from 55 to 80% by weight of fibers and from 20 to 45% by weight of the binder mixture. In a preferred embodiment, the binder mixture consists of from 0 to 10% by weight of phenolic resins and from 100 to 90% by weight of powder coated binders. The additives and adjuvants described above can be in an amount of up to 20% by weight, preferably up to 15% by weight, wherein the sum of all the components is 100%. Any r-evest powder waste material can be used. It is possible to use only one type of powder coating material or to use a mixture comprising a plurality of? Ni'-rno; an ezcla of resins of »? o? and polyester is preterred, however. In addition, the weight ratio of polyester powder to epoxide powder is preferably from 1: 0.2 to 7 ^ 1, more preferably from 0.8: 1 to 3: 1. When selecting powder coating materials, it should be ensured that they contain a sufficient number of reactive groups. Normal powder coating materials, compared to phenolic resins, often exhibit low interlacing speeds, due Its original purpose of application, where the good properties of flow and humidity are obtained during the coating. Within the scope of the present invention, it has been shown to be advantageous, when using powder coating materials, to adapt the corresponding facilities and processes for the production of chemically bonded fibrous webs and fibrous web molded articles to these binders. new. Therefore, the present invention also relates to processes for producing molded articles from fibrous webs and binder mixtures. These procedures can be adapted to the properties of the powders at first,. The process can be carried out using standard apparatuses which are suitable for the production of fibrous webs and fibrous web molded articles, for example, tools for molding in this respect, it can be advantageous, according to the invention, if they are The apparatus and the process control are adapted accordingly, respectively. One problem that may arise, for example, is that the powder coating materials, and the recirculated powder coating materials par- ticularly, may have flow properties with which they are different from those of the phenolic resins and phenol resin mixtures. . Therefore, it is advantageous to increase the output of a material supply station and to equip it so that its output can be regulated .. In addition, the funnel structure of a dosing roller used to feed the material, can be altered in a that can cover a larger scale of free flow. Another problem that may arise, for example, is the mixing of powder coating material or powder coating material recirculated as evenly as possible with the fibrous web. Therefore, according to the invention, the binder addition can be preferably carried out by means of a proportioning weft band. It is also recommended to subject the band which is provided with agglomeration to a treatment in the heating duct, for example, so as to adapt the temperature-1 temperature ratio. In particular, the melting point and the reaction rate of a powder coating material may differ from those of the phenol reams v. It was often found that a fibrous band bonded to the powder coating material exhibited a considerable tendency higher to paste both the conveyor belts and the press to mold. According to an embodiment according to the invention, in order to reduce this tendency to stick or cut the period in which there is an increased tendency to stick, the agglutinated fibrous web or a molding removed from the tool for molding can be dried. Therefore, a suction is used to dry increased in the conveyor belts. It may also be recommended that a cutting installation be provided to cut the fibrous band bonded to Length. Since the brittleness / hardness of the fibrous web is minor-as a result of the powder coating binder, it is recommended if the cutting knife line is no longer provided by a passive conductor but by a separate conductor, in order to generate friction Problems may also arise when the fibrous web is molded into a tool to be molded. Thus, it is recommended to accelerate the reaction speed and reduce the tendency of the fibrous band to stick. In accordance with the invention, this can be done using superheated steam, which accelerates the curing of the binder due to its high heat capacity. The superheated steam also reduces the adhesion to the tools for molding of the powder coating coating, which in a warm state is still very good. Taking into account the reduced tertiary or reduced properties of the powder coating binder compared to those of the phenolic resins, it is recommended to place the molded articles even in a plastic sheet so that they are removed after they have been removed. the tool for molding.

IH The binder mixture a), the prepregs, and the cured molded articles also contain a reduced proportion of free phenols or formaldehyde. The dangers due to these substances, which are harmful to health, are thus reduced. These molded articles can be r-coated as well or can be used as supports for other components. This can be done, for example, by applying a film to the surface of the molding simultaneously with the interlacing and by shaping the molded articles. It is also possible to obtain a special coating of the surface by the subsequent coating and lamination of the films. M all for laminating molded articles are widely used in the industry. They can be carried out in accordance with the prior art. It is also possible to impart a coating of fluff to the surface of the molded articles. In the course of this process, the short fibers are applied substantially vertically to the surface by means of adhesives, and then result in a smooth, dense surface. The lining methods are also known. The molded articles produced from the materials according to the invention can optionally be coated. In this regard, all coating means known in the industry can be used. the soft, glossy coatings are produced after heating.

The molded articles that are coated in this way exhibit a pronounced decorative effect. Depending on the selected procedure, smooth, smooth, milled or coated surfaces resistant to chemicals can be produced. Molded articles that are fire resistant can also be obtained by the additional use of flame retardant additives. The properties of the powder coating material during the production of fibrous web and fibrous web molded articles are satisfactorily considered by the process according to the invention, because the technical properties produced from the fibrous web and molded articles The fibrous webs are completely equivalent to those of the products that are produced from terrazzo plastics. However, a significant advantage is that even if the reaction of the powder coating materials is insufficient, no odor discomfort occurs. At the same time, an oilet i? Bu < Significant ion »is made to the protection of the environment, since the recirculated powder coating material is reused in the present process. The fibrous webs and molded articles can be used for normal purposes of application in the general fields, for example, in the automotive industry.

EXAMPLE 1 A mixture comprising 9 g of a commercially available powdered phenolic resin (novolac containing hexameti lentp amine), having an average particle size of 35 μm and an interlacing temperature of 150 ° C, and 40 g of a coating material in pigmented powder based on epoxy resin powder commercially available, as well as 50 g of a pigmented powder coating material based on polyester resins, where the powder coating materials had a pigment content of 10%, was furnace in a commercially available mixing unit. (polyester: epoxide - 1.25: 1, 10% phenol resin content i ca) The mixture could be stored for an extended period without additional loss of reactivity.

EXAMPLE 2 A mixture comprising a pigmented epoxy resin powder with 10% barium sulfate and 30.1 g of a non-pigmented polyeste powder coating material was prepared, and 0.4 g of tetrabutylaronium bromine was added, and the total mixture was homogenized completely. Filter powders from the production of powder coating materials were used as polyester powders or epoxy powders. These were furnace, and an average sample of these constituents was used later in the examples. Preprints were produced from the powders of Example 1 or 2 with a fibrous web, in a known manner, and which had more than 80% cotton fibers. For this purpose, the fibrous webs were mixed homogeneously, by means of mechanical movement, with the binder powder supplied by a proportioning weigher band and were passed through a heated pipe (approximately 2-3 minutes).; 80 ° C - 100 ° C). This resulted in preinpregnates that were stable in storage and where the resin and fibers had bound together. The prepreg was dried during cooling, by air flow over it. Molded articles were produced from these pre-impregnated. The prepregs were cut to size using a knife for cutting, articles molded into their desired shape in a press, and cured for 100 to 110 seconds at temperatures between 140 ° C and 160 ° C. In the course of this procedure, the temperature was obtained preferably by heating with superheated steam. After curing, the thermofixed plastic products were obtained and were dimensionally stable during heating. The density can be changed by the amount of prepreg or by the pressure that is adjusted. The interlaced molded articles that were produced were removed from the press molding, optionally dried in a stream of air and laid on a backing sheet. The molded articles obtained in this way were stable diesssionally after cooling, and had no content, or only a low content of free phenol or ld form.

Claims (16)

NOVELTY OF THE INVENTION CLAIMS

1. A process for producing fibrous webs and fibrous web molded articles, preferably in tools for molding, wherein the fibrous webs are chemically bonded with binders, further characterized in that the binder powders consisting entirely or partially of powder coating material, particularly recirculated powder coating material, are added to the fibrous webs.

2. A method according to claim 1, further characterized in that the binder is added by means of an aligning station of material that is adjusted for the binder.

3. A process according to claim 1 or 2, further characterized in that the binder is added by means of one or more dosing lodiiles, wherein the funnel structure of the dosing roller is altered to obtain a larger scale of free flow for the binder.

4. A process according to one of claims 1 to 3, further characterized in that the binder is added by a weigher band, 5.- A method according to one of claims 4, further characterized in that during the fibrous band molding to produce molded articles in tools for heat molding. The reaction is accelerated by the use of superheated steam to obtain more rapid cure of the binder. 6. A method according to one of claims 5, further characterized in that the superheated steam is introduced into the tool for molding at a pressure of 1 to 15 bar. 7. A process according to claim 4 or 5, further characterized in that the tool for molding is driven by superheated steam before introducing the mixture of fibrous web and binder. 8. A method according to one of claims 4 to 7, further characterized in that after the removal of the tool for molding, the molded articles are placed on a support sheet configured for cooling. 9. A method according to at least one of claims 4 to 8, further characterized in that the agglutinated fibrous web or the molding is dried. 10. A binder mixture for producing fibrous webs and molded articles made of fibrous webs according to any of claims 1 to 9, further characterized by having 0 to less than 30% by weight of phenolic resin and 100% by weight. to 70% by weight of materials of 5 powder coating waste. 11. A binder mixture according to claim 10, further characterized in that the epoxy reams and the polyester reams in a mixing ratio of 1: 0.2 to 1: 7 are used as powder coating waste materials. 12. The use of powder coating material, particularly matter of recirculated powder coating, as a binder or in binders to produce chemically bonded fibrous webs and fibrous web molded articles. 13. The use of binder mixtures according to claim 10, further characterized for producing articles molded from fibrous webs. 14. Use according to claim 12 or 13, further characterized in that the powder coating waste materials are reactive powder coatings based on epoxy, polyester, poly ur-ethane and / or Lato acp. 1

5. Use according to claim 12, 13 or 14, character-raised in addition because epoxy resins and polyether resins at a mixing ratio of 1: 0.2 to 1: 7 are used as powder coating waste materials. 1

6. Use according to one of claims 12 to 15, further characterized in that additives, particularly flame retardants, are added.