MXPA97008835A - Combination of melamine fibers / fiber natu - Google Patents

Abstract

The present invention relates to a fiber mixture containing: (a) from 10 to 90, parts by weight of melamine resin fibers, and (b) from 90 to 10, parts by weight of natural fibers, which is useful to produce woven fabrics, non-woven fabrics, threads, ribbons and moldings

Description

COMBINATION OF MELAMINE FIBERS / NATURAL FIBER The present invention relates to a fiber combination consisting of (a) from 10 to 90 parts by weight of melamine resin fibers and (b) from 90 to 10 parts by weight of natural fiber. The fibers composed of the melamine-formaldehyde condensation products are known, for example, from DE-B-23 64 091. These are non-combustible, flame-resistant and heat-resistant. For their properties they are used for the manufacture of fire-resistant textiles. However, there are applications for which the fibers are not strong enough and there are applications where the low resistance to abrasion is a disadvantage. The disadvantage of natural fibers is that they require the addition of flame retardants to make them non-flammable. However, natural flame-retardant fibers, such as cotton, lose some of the combustion resistance during washing, and the result is an increase in the risk of fire, for example, in the case of suits for fire fighting. welders An object of the present invention is to improve the properties of the melamine resin fibers on the one hand and the properties of the natural fibers on the other.

We have found that this goal is achieved by mixing previously defined fibers. This invention further provides mixtures of fibers that additionally include other fibers and / or metallic fibers or conductive polymeric fibers and also a process for their preparation and the use of the fiber blends of this invention to produce woven fabrics, non-woven fabrics, yarns, ribbons and molded parts and the use of melamine resin fibers to produce the fiber blends of this invention. In accordance with DE-B-23 64 091, the melamine resin solution used to spin the melamine resin fibers may have added to it, during spinning, solutions of other fiber-forming polymers, including solutions of polyamides in organic solvents. Preference is given to the addition of the aqueous solutions of the melamine resin solution of the polyvinyl alcohol as a way to improve the mechanical properties of the fibers that are produced by the spinning process. This reference, in this way, includes mixtures or solutions of different spinnable polymers to produce multicomponent fibers (blends of polymers within a single fiber), while the present invention includes the combination of various single-component fibers. already produced, to produce mixtures of fibers (mixtures of different fibers). A. Melamine resin fibers are notable for their resistance to high temperature and incombustibility. Its production and properties are known, for example from DE-A-23 64 091. These are preferably produced from highly concentrated solutions of the melamine-formaldehyde precondensation products after the addition of an acidic agent for curing, by spinning by centrifugation, stretching, extrusion or fibrillation. The fibers obtained are usually pre-dried and optionally stretched, and the melamine resin usually hardens from 120 to 250 ° C. The fibers are usually from 5 to 25 microns thick and from 2 to 2000 mm in length. Particularly thermostable fibers are obtained when up to 30 mol%, in particular from 2 to 20 mol% of the melamine in the melamine resin are replaced by a hydroxyalkylmelamine as described in EP-A 221 330 or EP-A 523 485. These fibers have a sustained use temperature of up to 200 ° C, preferably up to 220 ° C. In addition minor amounts of melamine can be replaced by substituted melamines, urea or phenol. Particular preference is given to the condensation products obtainable by condensation of a mixture that includes as essential components. (A) from 90 to 99.9 mol% of a mixture consisting mainly of (a) from 30 to 99 mol% of melamine and (b) from 1 to 70 mol% of a substituted melamine of the general formula I x wherein X, X 'and X "each are selected from the group consisting of -NH", -NHR and -RR', and X, X 'and X "are not all -NH2 and R and R' each one is selected from the group consisting of C2-C6 hydroxyalkyl / C2-C2 hydroxyalkyl, - (C2-C4 oxaalkyl) n, wherein n is from 1 to 5 and aminoalkyl from 2~2, or mixtures of melamines I, and (B) from 0.1 to 10 ?; mol, based on (A) and (B) of phenols which are unsubstituted or substituted by radicals selected from the group consisting of C1-C9 alkyl and hydroxyl, C?-C4 alkanes substituted by 2 or 3 groups phenols, di (hydroxyphenyl) sulfones or mixtures thereof. with formaldehyde or compounds that provide formaldehyde in a molar ratio of melamines to formaldehyde within the range of 1: 1.15 to 1: 4.5. The following compounds are substituted melamines particularly suitable for this invention: melamines substituted with 2-hydroxyethylamino such as 2- (2-hydroxyethylamino) -4,6-diamine-1,3,5-triazine, 2,4-di (2) -hydroxyethylamino) -6-amino-1,3,5-triazine, 2,4,6-tris (2-hydroxyethylamino) -1,3,5-triazine, melamines substituted with 2-hydroxyisopropylamino such as 2- (2-hydroxyisopropylamino) ) -4,6-diamino-1,3,5-triazine, 2,4-di (2-hydroxyisopropylamino) -6-amino-1,3,5-triazine, 2,4,6-tris (2-hydroxyisopropylamino) ) -1, 3, 5-triazine, melamines substituted with 5-hydroxy-3-oxapentylamino such as 2- (5-hydroxy-3-oxapentylamino) -4,6-diamino-1,3,5-triazine, 2, 4 -di (5-hydroxy-3-oxapentylamino-6-amino-1,3,5-triazine, 2,4,6-tris (5-hydroxy-3-oxapentylamino) -1,3,5-triazine, substituted melamines with 6-aminohexylamino such as 2- (6-aminohexylamino) -4,6-diamino-1, 3,5-triazine, 2,4-di (6-aminohexylamino) -6-amino-1,3,5- triazine, 2, 4, 6-tris (6-aminohexylamino) -1, 3, 5-triazine or mixtures thereof, for example, a mixture of 10 mol% of 2- (5-hydroxy-3-oxapentyl-amino) -4,6-diamino-1,3,5-triazine , 50 mol% of 2,4-di (5-hydroxy-3-oxapentylamine) -6-amino-1, 3,5-triazine and 40% mol of 2,4,6-tris (5-hydroxy-3-) oxapentylamine) -1, 3, 5-triazine. Preferred suitable phenols are phenol, 4-methylphenol, 4-tert-butylphenol, 4-n-octylphenol, 4-n-nonylphenol, pyrocatechol, resorcinol, hydroquinone, 2,2-bis (4-hydroxyphenyl) propane, 4, 4 '-dihydroxydiphenylsulfone, particularly preferably phenol, resorcinol and 2,2-bis (4-hydroxyphenyl) propane. In general, formaldehyde is used as an aqueous solution having a concentration, for example, from 40 to 50% by weight or in the form of compounds that provides formaldehyde during the course of the reaction, with (A) and (B) , for example as oligomeric or polymeric formaldehyde in solid form such as paraformaldehyde or, 1,3,5-trioxane or 1, 3, 5, 7-tetroxocane. The fibers are produced using, conveniently, from 1 to 50, preferably from 5 to 15, in particular from 7 to 12 mol% of the substituted melamine and also from 0.1 to 9.5, preferably from 1 to 5 mol% of one of the aforementioned phenols or mixtures thereof. B. The natural fibers that are generally used are the fibers found in nature based on cellulose, such as cotton, wool, linen or silk, whose natural fibers may also comprise cellulose-based fibers that are of natural origin but that they have been modified or treated by the known and customary processes. According to the German Standard Specification DIN 60001, cotton and wool in particular are natural fibers, cotton belongs to the group of vegetable fibers. The specification of the German standard DIN 60004 defines what is meant by the term wool. For the purpose of this invention, wool may comprise all fine or non-fine hair of animal origin. In addition, the melamine resin fibers may contain customary additives such as fillers, colorants, pigments, metallic powders and delustrants or may already be dyed. In the same way, the natural fibers may have been dyed and lubricated by the yarn before processing. The two fiber varieties are usually intermixed in conventional fiber mixing apparatuses as described in Vliesstoffe, Gerog Thieme Verlag. The initial materials are short fibers usually from 1 to 20 cm in length. These are usually fed through a conveyor medium in a flat cardboard and pre-mixed therein. The intermixing is then completed in a carton of rolls. The wadding obtained is then processed further into non-woven yarns or fabrics, for which the usual processes in the textile industry can be used. Depending on the field of application, these yarns, non-woven fabrics or fabrics can then also be processed into various textile or non-textile structures such as, for example, gloves, fire-fighting suits and also fire-proof blankets. These combined yarns or non-woven articles of these blends are notable for their excellent wearing comfort. However, the overhang characteristic is that the yarns, woven or nonwoven fabrics with melamine resin fiber content, at least 50 to 50% by weight, do not burn, although the natural fibers can be used without any finishing fireproof. A preferred embodiment refers to a fiber combination consisting of: (a) from 10 to 90, preferably from 30 to 70 parts by weight of melamine resin fibers, (b) from 90 to 10, preferably from 70 to 30 parts by weight of natural fibers, and (c) from 2 to 25, preferably from 5 to 15 parts by weight based on (a) and (b), of other fibers. The other suitable fibers include fibers of non-flammable or low-flammable materials such as m- and p-aramides, glass, polyimides, polybenzimidazoles, carbon, pre-oxidized polyacrylonitrile and also fibers composed of thermoplastic polymers such as high density polyethylene, polypropylene, polyesters, polyamides , polyvinyl chloride or polyvinyl alcohols. From observations to date, the addition of other fibers makes it possible to produce woven and nonwoven fabrics with greater strength than woven and non-woven fabrics without the other fibers, without adversely affecting fire behavior. Another preferred embodiment relates to blends of fibers consisting of (a) from 10 to 90, preferably from 30 to 70 parts by weight of melamine resin fibers, (b) from 90 to 10, preferably from 70 to 30 parts by weight of natural fibers, and (c) optionally, from 2 to 25, preferably from 5 to 15 parts by weight, based on (a) and (b) of other fibers as described above, and (d) from 0.1 to 5, preferably from 0.5 to 2 parts by weight, based on the sum of (a) + (b) + (c) of metallic fibers or conductive polymeric fibers.

Suitable metallic fibers include, for example, those based on stainless steel. Suitable conductive polymer fibers include those having a core of polyamide, polyester and a conductive coating and also melamine resin fibers coated with metal as described in EP-A-528 192, preferably those with a polyester core. Another preferred embodiment is to use metal-coated melamine resin fibers, preferably aluminum-coated melamine resin fibers, whereby also mixtures of melamine resin fibers covered or not covered with metal are understood. More particularly, the melamine resin fibers coated with aluminum can be produced in a conventional manner, for example, by adhering an aluminum foil or an aluminized film to the melamine resin fibers or by subjecting the melamine resin fibers. to a process of deposition of aluminum at high vacuum in steam. The thickness of the metal layer, especially the aluminum layer, is usually selected within the range of 10 to 150 microns, preferably within the range of 50 to 100 microns. The metallization is usually carried out by subjecting the fabric to a process of metal deposition in steam at high vacuum (see Ullmann's Enzykiopadie der Technischen Chemie, 3rd edition, vol.15, p.276 and the references mentioned herein) . It is also possible to adhere thin metal sheets to the fabric. These metal foils usually consist of polymeric support films that have been coated with a thin film of metal. These preferably consist of a polymeric support based on polyester. Metallized films are suitable according to German Armed Forces Supply Specification TL 8415-0203 for application to the fabric of the invention on one or preferably both sides thereof, for example by means of an adhesive or by thermal calendering. These sheets are used by different manufacturers for the coating of fabrics (for example, Gentex Corp., Carbondale PA, EU, C.F. Plucquet GmbH &Co., D-89522 Heidenheim, Darmstdter GmbH, D-46485 Wesel). It is also possible to produce the fabrics of the invention from the metallized ones. These wires are preferably coated with aluminum in layer thicknesses in the range of 10-100 microns. These yarns are producible, for example, in the process lines as described in DE-B 27 43 768, DE-A 38 10 597 or EP-A 528 182. Mixtures of 50% by weight of Basofil and 50% by weight of non-flame-retardant cotton comply, in accordance with pr EN 532, with the requirements of the limited flame dispersion index 2 defined in pr EN 533. A mixture of 60% by weight of Basofil and 40% by weight of non-flame retardant cotton achieves a fire rating of s_ according to the specifications of the German standard DIN 54336 and DIN 66083. The composite fabrics of the blends of this invention are very useful for protective suits for welding and steel making, in particular for heat protection conductive, radiant heat and splashes of liquid metal. The woven or nonwoven fabrics of this invention produced from the fiber blends of this invention that include thermoplastic fibers can be processed by conventional methods into articles formed as protective hoods for thermal insulation, in which case the thermoplastic fibers therefore general act as binder or adherent fibers. In addition, the fiber blends of this invention can be used to produce yarns and tapes in a conventional manner.

EXAMPLES Example 1 50 tex / 2 yarns were spun in ring-shaped from a composite mixture of 60% by weight of melamine resin fibers (BASOFIL® from BASF, produced in the same manner as in the example of EP- A 624,665) and 40% by weight of non-fire retardant cotton (from Russia, with an average length of 32 mm). The yarn thus produced was woven in a 2/2 twill with a basis weight of 310 g / m2. The fabric thus produced was tested in accordance with DIN 54336 and the parameters for the fire performance of the textile products were determined in accordance with DIN 66083. The fabric produced according to the invention obtained a fire class St,. For comparison: a woven fabric produced in the same way as cotton was completely consumed under the conditions of the test, so that classification in a class against fire is not possible.

Example 2 A mixture composed of 50 parts of melamine resin fibers (as in Example 1) and 50 parts of non-flame retardant cotton (as in Example 1) was used to produce a load web or web with a basis weight of 400 g / m2 through a work with a Pilo machine. The non-woven fabric thus produced was investigated for its fire behavior as described in Example 1. Result: the non-woven fabric achieved fire classification s_.

The fabric was found to have a final tensile strength of 520 N in a tensile test strip with the guidelines of DIN 53857. Example 3 A mixture of 45 parts of melamine resin fibers (as in Example 1) and parts of non-flame-retardant cotton (as in Example 1) and also 10 parts of polypropylene fibers (15 mm in length, 15 microns in diameter) was used to produce a perforated felt with a basis weight of 400 g / m2 by a work with a Pilo machine. The fabric thus produced was calendered at 200 ° C. The calendered fabric was then investigated for its fire behavior in the same manner as the method of Example 1. Result: the fabric achieved fire classification s_. The calendered fabric was found to have an ultimate tensile strength of 740 N in the tensile test strip DIN 53857.

Example 4 Example 3 was repeated with the mixture of Example 2. The final tensile strength of the calendered fabric was 620 N.

Example 5 A mixture consisting of 601 by weight of BASOFIL® (as in Example 1) and 401 by weight of un-ignited cotton (as in Example 1) was spun with a rotor to produce a yarn with a linear density of 50 tex . Then a double strand was produced in a customary bending machine. This strand was woven in a conventional glove weaving machine to produce gloves with fingers. The weight per glove was 54 g. The base weight was 800 g / ra. A threshold time of 14.6 seconds was determined at a contact temperature of 250 ° C in accordance with the European standard EN 702. For the comparison a para-aramid glove of the same weight was tested. At the same contact temperature, the threshold time was found only of 8.9 seconds.

Example 6 Threads of Nm32 / 2 were spun into ring-shaped from a composite mixture of 64% by weight of melamine resin fiber (BASOFIL® from BASF), 35% by weight of commercially available New Zealand wool and also 1% by weight of steel fiber (diameter 6 microns, 36 mm in length). This yarn was then woven to produce a flat weave with a basis weight of 275 g / m2.

The tests selected in accordance with DIN EN 531: 1995, protective clothing for industry workers exposed to heat. 1. Limited flame dispersion as defined in DIN EN 532: 1995 Continuous combustion towards the upper and lateral edges no Drilling no Dripping by combustion or not Fusing Time after exhaustion 0 seconds Luminescence time 0 seconds Residual As a result, the fabric exceeds by far the requirements of DIN EN 531 (code letter A). This rule in fact allows two seconds for the time after exhaustion and the residual luminescence time. 2. Convective heat as defined in DIN EN 367: 1992 HTI value 6 seconds The fabric reaches a performance level Bl of DIN EN 531: 1995 3. Radiant heat as defined in DIN EN 366: 1993 value t 20 seconds fabric reaches an operating level Cl of DIN EN 531: 1995 Liquid iron splashes as defined in DIN EN 373: 1993 Iron mass that does not cause damage to a PVC film 62 g The fabric achieves an operating level The DIN EN 531: 1995 Tests in accordance with DIN EN 470-1: 1995, protective clothing for welding processes and related .lor of the test Required by the standard 1. Warp resistance 550N > 300N traction ISO 5081 frame 490N > 300N2. Warp resistance 54N > 15N ISO ripping 48N > 15N 4674 3. Warp change -2.5% < + 3% dimensional ISO plot -0.7% < + 3% 6330/5077 4. Response to small metal splashes as defined in DIN EN 348: 1992 Number of metal droplets causing a 4K temperature rise on the reverse side of the sample 33 > fifteen

Claims (6)

2. . A fiber mixture consisting of (a) from 10 to 90 parts by weight of melamine resin fibers and (b) from 90 to 10 parts by weight of natural fibers. . The fiber mixture according to claim 1, wherein the fiber mixture consists of (c) from 2 to 25 parts by weight, based on the sum of (a) and (b), of other fibers. . The fiber blend consists of (a) from 10 to 90 parts by weight of melamine resin fibers, (b) from 90 to 10, parts by weight of natural fibers, and also, optionally, (c) from 2 to 25. , parts by weight, based on the sum of (a) and (b), of other fibers and (d) from 0.1 to 5, parts by weight, based on the sum of (a) (b) (c) , of metallic fibers or conductive polymer fibers. . The fiber mixture according to any one of claims 1 to 3 consists of melamine resin fibers coated with metal or mixtures of uncoated melamine resin fibers coated with metal as component (a).
3. . A process for producing a mixture of fibers, according to claim 1, 2 or 3 by the usual processes, which consists of mixing
4. (a) from 10 to 90 parts by weight of melamine resin fibers, and (b) from 90 to 10 parts by weight of natural fibers, and also, optionally, (c) from 2 to 25 parts by weight based on the sum of (a) and (b), of other fibers and, optionally, (d) from 0.1 to 5 parts by weight, based on the sum of (a) (b) (c), of metal fibers or fibers conductive polymer . The use of the fiber mixture of any of claims 1 to 3 or produced in accordance with claim 4 for producing woven, nonwoven, yarn, ribbons or molded goods, in particular gloves, suits for fire protection, blankets Fireproof, protective clothing for welders and clothing for protection against conductive heat, radiant heat and splashing of liquid metal. . The use of the melamine resin fibers to produce fiber blends, according to any of claims 1 to 3.
5. Gloves, suits for fire protection, fireproof covers, produced by the use of claim
6. 6. Protective clothing for the welder and clothing for protection against convective heat, radiant heat and splashes of liquid metal, by use of claim 6.