MXPA98005481A - Method to make polyamides of metallic effect with development and brightness of color improves - Google Patents

Abstract

A method for preparing improved metal effect nylon materials and the nylon materials produced by this method is described. In particular, the invention relates to a process in which the metallic effect flake pigment is added as a hot feed to fused nylon compositions and then extruded, molded or otherwise configured to an article desired.

Description

METHOD TO MAKE METALLIC EFFECT POLYAMIDES WITH DEVELOPMENT AND IMPROVED COLOR BRIGHTNESS Field of the Invention The present invention relates to a method for improving the metallic appearance of nylon materials produced by this method. In particular, the invention relates to a process in which the aluminum pigment is added as a hot feed to fused nylon compositions and then / "extruded, molded or otherwise configured to a desired article.

Background and Compendium of the Invention Nylon resins are used to make many different products for which good physical properties are important such as tensile strength, stiffness, and the ability to withstand high temperatures. In many of these articles, the aesthetic or design aspects are also of great importance. Although polyamides have displaced metallic materials in many applications due to the good physical properties and the comparatively light weight and ease of fabrication of nylon materials, there remains a doubt in using polyamides in other applications due to the difference in appearance of the polyamide and metallic materials. For example, automotive parts exposed to elevated temperatures in the engine compartment of motor vehicles, such as intake manifolds, cylinder head covers, and engine compartment covers, can advantageously be made of polyamide materials, especially engineered materials. reinforced polyamide. The visual difference between the natural polyamide materials and the metals from which said parts have been made in the past, however, presents a disadvantage in terms of design. In the past, providing articles with a metallic appearance has involved tedious, time-consuming and / or costly methods of treating the articles after molding, extrusion or other training stage. For example, molded or extruded polyamide parts have been painted or metallized to produce a metal-like appearance. In addition, methods such as painting or metallization require specialized equipment and can produce unwanted regulated emissions. In this way, it would be desirable to provide a metallic appearance polyamide material that provides a visually appearing part similar to the metal without any further processing.

In an improved process, the nylons with a metallic effect prepared by mixing nylon granules with a metallic effect pigment, preferably aluminum luster, and then feeding the mixture towards a screw extruder or a Brabender mixer to produce a uniform composition. The resulting composite material can be molded or shaped into parts that have a good metallic appearance. The disadvantage of this method is that the compositions are generally limited to dark gray blue colors as a consequence of a substantial generation of broken and folded aluminum flakes during the composition operation. The addition of white or yellow pigments produces slightly lighter colors; however, substantial additions of pigments attenuate the gloss effect by producing more opaque materials. Parts made with this material in this manner tend to be too dark and have a blue component too strong for many applications where a clear metallic appearance or metallic colored appearance is desirable.

SUMMARY OF THE INVENTION A method has now been discovered to improve both the gloss and the metallic effect of nylon materials which can be achieved by substantially melting the nylon resin component before the addition of a metallic effect flake pigment in a process which will be referred to in this specification as "hot feed" of the metallic effect flake pigment. In a preferred embodiment, the process of the invention includes a step of adding the metallic effect flake pigment directly to a substantially melted nylon material, for example through a gate in the melting zone of an extruder of composition. The invention further provides a nylon material with improved metallic appearance and improved gloss including a nylon resin and a metallic effect flake appearance produced in accordance with the method of the invention which has unexpectedly improved the brightness and color; The nylon materials of the invention have a more pronounced metallic effect, even at a lower content of the metallic effect flake pigment, than the materials produced by cold feeding of metallic effect pigment and the The nylon materials of the invention can be modified with small amounts of other pigments to achieve light-colored metallic appearance materials which could not be obtained by prior methods.

Detailed Description The present invention provides a process for preparing a metallic appearance polyamide (nylon) material with superior gloss and color development. The appearance polyamide materials metal of the present invention include a resin of ^ polyamide, a metallic effect flake pigment, and ^ optionally, a mineral reinforcing agent or other additives. In accordance with the method of the invention, the polyamide resin is substantially melted, and optionally mixed with one or more additives, and then the flake pigment, optionally together with one or more mineral reinforcing agents is mixed into the fusion. The term "substantially molten" is used to describe the polyamide resin in a state in which approximately three-quarters or more of the solid resin has been melted so that the melt forms a substantially continuous phase. The polyamide compound with the metallic effect pigment is then formed into a desired configuration The metallic effect flake pigments which are useful in the methods and materials of the invention include metallic flake pigments and pearls The useful metallic flake pigments they include aluminum, copper metals, nickel, magnesium, zinc, brass and bronze and alloys of these.The important types of pearlescent pigments that are useful as the flake pigments of the invention are micas coated with metal oxides, such as micas. of titanium dioxide and / or coated with iron oxide, and pigments of bismuth oxychloride In general, pigmen are preferred cough % flake of relatively large metallic effect, and these flake pigments can be made at about 1.0 mm in a longer dimension. The pigments of The metal effect flake preferably has a size distribution in which about 90% of the material is less than about 0.5 mm and 50% of the material is less than about 0.3 mm, as measured for the longer dimension. Preferably, the metallic effect flake pigments are at least about 0.05 mm as measured for the longest dimension. Even when the metallic effect flake pigments can be of irregular configurations, especially for foil molding or for compounds of polyamide to be used to form other simple shapes, the pigments with regular configurations, which are commonly called "gloss", are preferably square and / or rectangular flake configurations, preferred for the polyamide compounds that will be used to form configurations more complicated. The gloss generally refers to the metallic particles produced by cutting or stamping uncoated or transparently coated metal films. Stamped metallized plastic films or other metallized carrier materials can also be used. Preferred gloss materials are aluminum, copper and steel bronze coated or uncoated. The gloss is preferably rectangular or square, with an edge length of at least about 0.01 mm, preferably at least about 0.05 mm, or an edge length of up to about 1 mm, preferably up to about 0.4 mm. The square-shaped flakes of about 0.1 mm on one side are particularly preferred. It is also highly preferred to use flake pigments which have substantially uniform sizes, i.e., which have relatively narrow size distributions. Regular shapes and narrow size distributions are considered to minimize the occurrence of flow lines or weld marks when forming articles that have complicated configurations. An important criterion for a narrow size distribution is that there is a minimum amount of "fines", the most small size material. The metallic effect flake pigment preferably contains less than about 1% by weight of material having a length of less than about 50 microns. The fine content of the particles can be determined by sieving, as in accordance with ISO method 787/7. The amount of fines can be determined by the fraction not retained in a * sieve of a specified mesh size. The pearlescent pigments should have an average particle size of at least about 50 micrometers, preferably at least about 100 micrometers. The surfaces of metal flakes that tend to oxidize easily, such as aluminum, are preferably coated by a method known in the art. technique. The aluminum or gloss flakes preferably have a polymeric coating, such as a polyurethane coating, even when aluminum flake pastes in plasticizers such as dioctyl phthalate or diisononyl phthalate may be useful for certain applications. The brightness of aluminum having a polyurethane coating is particularly preferred. Aluminum can also be added as a granule of aluminum-colored concentrate in polyethylene wax. A typical granule has 80 to 90% of * metallic pigment by weight, up to about 5% polyethylene wax, and the rest dispersing agents or other ingredients. Metallic effect flake pigments are widely available commercially, for example, The Mearl Corporation, Briarcliff Manor, Ny under the trade names MEARLIN8M and MEARLITE8B9; EM Industries, Inc., Nawthorne, NY under the trademark AFFLAIR8R9; Obron Atlantic Corp., Painesville, OH, under the brands STANDART8K9, STAPA8M, and MÁSTERSÁFE889; Transmet Corp., Columbus, OH; Glitterex Corp., Cranford, NJ, under the trade name Alu * Flake WSR8R9; Silberline, Tamaqua, PA; Aluminum Company of America, Pittsburgh, PA; Reynold Metals Company, Richmond, VA; and Toyo Aluminum KK, Higashiku, Osaka, Japan. In general, the polyamides included in the polyamide compounds according to the invention have a viscosity of at least about 90, more preferably at least about 100 mL / g. , as determined in accordance with the ISO 307 method for a solution of 0.5% by weight in 96 weight percent of sulfuric acid at 25SC. Semi-crystalline and amorphous polyamides are preferred, particularly those having a weight-average molecular weight of at least 5000, such as those described in the U.S.A. Nos. 2,071,250, 2,071,251, 2,130,523, 2,130,948, 2,241,322, 2,312,966, 2,512,606, and 3,393,210, each of which is incorporated herein by reference. Illustrative examples of suitable polyamides include those derived from lactams with 7- to 13-membered rings, such as polycaprolactam, polylactyl lactam, and polylauryl lactam, as well as polyamides obtained by a reaction of a polycarboxylic acid, preferably an acid Dicarboxylic, with a polyamine, preferably a diamine. Examples of suitable polyacids include, without limitation, alkalicarboxylic acids having at least about 6 carbon atoms and up to about 12, preferably up to about 10, carbon atoms; and aromatic dicarboxylic acids. Particular examples include adipic, azelaic, sebacic, dodecanediocarboxylic, terephthalic, phthalic and isophthalic acids and anhydrides and mixtures thereof. Suitable polyamines include, without limitation, Alkanediamines having at least about 6 carbon atoms and alkanediamines having up to about 12, preferably up to about 8, carbon atoms. Particular examples of useful polyamines are m-xylylenediamine. 25 • ^ sm di- (-aminophenyl) methane, di- (-aminocyclohexyl JMethane, 2, -di- (4-aminophenyl-Jpropanol, 2,2-di- (4-aminocyclohexylpropane, and mixtures thereof. nylons (polyamides) that can be used in the processes and compounds of the invention include, without limitation, nylon-6, nylon-6,6, nylon-6,10, nylon-4,6, nylon-6,12, nylon-11, nylon-12, and nylon 6/66, particularly with from about 5 to about 95% by weight of caprolactam units; nylon copolymers partially aromatic such as nylon-6/6, T, nylon-6, 6/6, 1/6, T; and so on, and mixtures of these. The appropriate nylons are available from BASF Corporation, Mt. Olive, NJ under the trade name ULTRAMID8R9. Preferred among these is nylon-6 and nylon-6,6. The nylons used in the invention have average molecular weights in number preferably at least about 10,000 and more preferably at least about 15,000. The number average molecular weights of preferred nylons can be up to about 40,000 and particularly up to about 20,000. The nylon resins used to prepare the metallic appearance nylon of the invention preferably have a polydispersity of less than about 4 and more preferably less than about 2.5. The nylon resin may be included in the nylon material in an amount of at least about 40%, preferably at least about 505, and even more preferably at least about 60%, based on the weight of the composite nylon material. The nylon resin can also be included in the nylon material in an amount of up to about 99%, preferably up to about 90%, more preferably up to about 80%, and even more preferably up to about 70%, based on the weight of the Composite nylon material. The metal effect pigment can be included in the nylon composition in an amount of at least about 0.1%, preferably at least about 0.5%, more preferably at least about 1%, and particularly preferably over at least about 1.5% by weight, in addition, the metallic effect flake pigment can also be included in the nylon composite in an amount of up to about 5%, preferably up to about 3%, and particularly preferably up to about 2.5% by weight. Because the compositions of the invention have a more pronounced metallic effect compared to compositions ^ -. produced in accordance with other methods, it is usually possible to include the metallic effect flake pigment at lower concentrations to produce the desired metallic effect. Thermal stabilizers should be phenols and hindered phosphites, copper iodide or other stabilizers that would color the materials are not preferred. In a preferred embodiment of the invention, one or more stabilizers such as thermal stabilizers or antioxidants are included in the composite nylon materials. It is usually preferred to include colorless stabilizers so that the addition of the stabilizer does not displace the intended color of the composition. The stabilizers particularly useful include spherically hindered phenolic compounds, phosphorous acid, hypophosphites and combinations thereof. Sterically hindered phenolic compounds include, without limitation, compounds derived from substituted benzenecarboxylic acid and hindered phenols described in the patent of E.U.A. No. 4,360,617, incorporated herein by reference. Specific examples include, without limit, 2 * 2"- methylenebis- (4-methyl-6-tert-butylphenol), 1,6-hexandiolbis- [3- (3, 5-di-tert-butyl-4- hydroxyphenyl) pro- 25. ^ P "pionate], 3,5-di-tert-butyl-4-hydroxybenzyl phosphonate phosphonate, 2,6,7, -trioxa-l-phosphabicyclo [2.2.2. ] oct-4-ylmethyl-3, 5-di-tert-butyl-4-hydroxycinnamate, 3,5-di-tert-butyl-4-hydroxy-3-yl, 5-distearylthiotriacylamine, 2- (2-hydroxy-3-yl) -hydroxy-3i, 5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2,6-di-tert-butyl-4-hydroxymethylphenol, 1,3,5-trimethyl-3, 6-tris- (3 , 5-di-tert-butyl-4-hydroxybenzyl-benzene, 4,4'-methylenebis- (3,6-di-tert-butylphenol, 3,5-di-tert-butyl-4-hydroxybenzyldimethylamine) N, N '-hexamethylenebis-3, 5-di-tert-butyl-4-hydroxycinnamide, and combinations thereof Useful sterically hindered phenolic compounds are available under the brand name Irganox (R), from Ciba-Geigy Corp. , Tarrytotfn, NY, under the Lowinox brand of Great Lakes Chemical, West Lafayet e, IN; and Hos anox, Hoechst AG. Particularly preferred is N, N '-hexamethylbenbis-3, 5-di-tert-butyl-4-hydroxycinnamide, tetrakis- [3- (3, 5-di-tert-butyl-4-hydro? Ifenyl) propionate] of pentaerythritol, twenty n-Octadecanoyl-3-γ 3, 5-di-tert-butyl-4-hydroxyphenyl Jpropion ato, glycolic acid ester bis-3, 3-bis- (4 '-hydroxy-3'-tert-butylphenyl) - butanoic or mixtures thereof, commercially available under the trade names Irganox (R) 1098 (Ciba-Geigy), * Lowinox (R), HD 98 (Great Lakes Chemical), IrganoxCR 1010. { Ciba-Geigy), Hostanox (R) 010 (Hoechst), Irganox (R) 1076 (Ciba-Geigy), h Hostanox (R) 03. { Hoechst). The spherically hindered phenolic compounds are included in amounts of at least about 0.05% by weight, preferably at least about 0.1% by weight, and even more preferably, at least about 0.2% by weight. The sterically hindered phenolic compounds are also included in amounts of up to about 2% by weight, of preferably up to about 1% by weight, and particularly preferably, up to about 0.6% by weight. Preferred compositions of the invention include one or more thermal stabilizers containing , Phosphorus, preferably one or more compounds selected from phosphorous acid and phosphorous acid esters, hypophosphites and mixtures thereof. Phosphorus can be in a valence state of +1 or +3. Thermal stabilizers are included in amounts of At least about 0.05% by weight, and also preferably are included in an amount of up to about 2% by weight, preferably up to about 1% by weight, and particularly preferably up to about 0.5% by weight. The examples Specific to useful compounds in which phosphorus has a valence status of +1 include, without limit, salts such as alkali metal hypophosphites including sodium hypophosphite, calcium hypophosphite, magnesium hypophosphite, and amine salts such as hypophosphite of melamine; double, complex or organic hypophosphites such as cellulose hypophosphite esters, esters of hypophosphorous acids and diols such as 1,10-dodecandiol; substituted phosphinic acid and anhydrides such as diphenylphosphinic acid, di-p-tolylphosphinic acid, dicresylphosphinic anhydride, bis- esters. { diphenylphosphinic acid) of hydroquinone, ethylene glycol or other polyols; and aryl (alkyl) phosphonamides such as dimethylamide diphenylphosphinic acid and sulphonidoaryl (alkyl) phosphinic acid derivatives such as p-tolylsulfonamidodiphenylphosphinic acid.Specific examples of useful compounds in which phosphorus has a valence state of +3 include, without limit, cyclic phosphonates derived from pentaerythritol, neopentyl glycol, and pyrocatechol; triaryl (alkyl) phosphites such as triphenyl phosphite, tri- (4-deCylphenyl) phosphite, tri- (2,4-di-tert-butylphenyl) -phosphite and phenyl-di-decyl phosphite; diphosphites such as propylene glycol 1,2-bis-. {diphosphite); cyclic phosphites; and derivatives of phosphorous acid esters such as 2-. { [2,, 8, 10-tetrakis (1,1-dimethylethyl) -diben [D, F] [1,3, 2] -dioxaphosphepin ~ 6-yl] oxy} -ethyl Jetan-amine and tris-2, -di-tert-butylphenyl) phosphite. These stabilizers are commercially available under the trade names Irgafos (R) of Ciba-Geigy and Hostanox (R) of Hoechst AG. Preferred materials are Irgafos (R) 12, Irgafost) 168, and Hostanox ^ 1 PAR 24. Thermal stabilizers containing phosphorus are included in amounts of at least about 0.05T by weight. Thermal stabilizers containing phosphorus are also included in amounts of up to about 2% by weight, preferably up to about 1% by weight, and particularly preferably up to about 0.5% by weight. The nylon material of the invention may also comprise a reinforcing agent which may be a fibrous material or, preferably, a mineral reinforcing agent. Useful fiber reinforcements include. Without limitation, glass fibers, especially E glass fibers, carbon fibers and graphite, polymeric fibers including aramid fibers, boron filaments, ceramic fibers, metal fibers, asbestos fibers, potassium titanate fibers, fibers of beryllium, silica fibers, silicon carbide fibers and so on successively. The fibers can be surface treated, for example with a silane, for better compatibility with the nylon resin. The fibers can be conductive and said conductive fibers, for example conductive carbon fibers or metal fibers, can be used to produce articles for conductive dissipation or static charge applications or protection • EMI. Among these, fiber fibers, carbon fibers and aramid fibers are preferred. Methods for preparing thermoplastic resins including said fibers with well known in the art. Wicks or staple fibers can be used. In one method, bundles of cut glass fiber are fed into the melting zone of the extruder that is being used to form the metallic effect nylon material.

Alternatively, the fiber is introduced as a continuous fluff or beam towards a port in the extruder. The reinforcing agent of the invention preferably comprises a mineral reinforcing agent. Suitable mineral reinforcing agents include, without limit, wollastonia, micas, glass beads. { solid or hollow), kaolin, calcined kaolin, chalk and talcum. The micas and other reinforcing agents can be treated, for example, with coupling agents such as silanes to improve the mechanical properties or with a nickel coating for special applications. Preferred mineral reinforcing agents are wollastonites, micas, kaolins and talc. Mineral reinforcing agents are typically incorporated into the resin by feeding through a hopper into a melting zone of the extruder. In a particularly preferred embodiment of the invention, the metallic effect pigment is mixed with mineral filler before addition to a substantially melted polyamide resin. Mixing with uii The mineral filler is useful for dilution of the metallic effect pigment, for example, when an amount of the metallic effect pigment would otherwise be difficult to dose accurately towards the polyamide melt, and / or to prevent agglomeration of the effect pigment.

T. Metallic in the addition equipment. Mixing with a mineral filler is particularly useful for pearlescent pigments because blending tends to make the bulky, bulky, less density pearlescent pigments easier to handle. the mixing of a mineral filler and The metallic effect pigment can be achieved, for example, by dry mixing, for example in a drum mixer by stirring until it is uniform. The reinforcing agent can be, and in many # casps is preferred, a combination of reinforcing fibers and reinforcing minerals. For example, in one embodiment the reinforcing agent is a combination of glass fibers and wollastonite. The reinforcing agent or agents are included in amounts of at least about 1%, preferably at least about 5%, more preferably at least about • 15%, and even more preferably at least about 25%, based on the weight of the composite resin. The reinforcing agent or agents are included in amounts up to about 70%, preferably up to about 60%, and even more preferably up to about 50%, based on the weight of the composite resin. Typically, from about 25% to about 60% reinforcing agent is included in the nylon compound. The nylon materials may also include at least one additional additive. Examples of suitable additives include, without limitation, plasticizers; thixotropes; optical brighteners; antioxidants; UV stabilizers, including resorcinols, syncylates, benzophenones, hindered amine light stabilizers such as benzotriazoles, and hindered amide light stabilizers; flame retardants; pigments and dyes; processing aids such as lubricants, mold release agents and slip agents, fragrances; antifoaming agents; antioxidants such as hydroquinone, aromatic secondary amines and derivatives thereof, antistatic agents; antimicrobials; biocides; and so on. Impact modifiers, such as ionomers, malleable elastomers, and * natural and synthetic rubber particles and other materials that would tend to form discrete phases can be included in relatively minor amounts for get good metallic appearance. Processing aids such as polytetrafluoroethylene homopolymers and copolymers may be included. The nylon composition may include one or more pigments or colorants in addition to the flake pigment. From fifteen *?? Preferably, the pigment is present in an amount of up to about 4% by weight, and especially up to about 2% by weight based on the weight of the resin. The appropriate pigments are black, white or colored pigments. Examples of useful pigments include, without limit, titanium dioxide, zinc oxide, zinc sulfide carbon black, iron oxide black, copper chromate black, yellow iron oxides, red iron oxides, brown iron oxides, ocher, siena, hematite , limonite, mixed iron oxides, oxide ^ _W chromium, Prussian blue (ammonium ferrocyanide), chromium green, chrome yellow, manganese violet, cobalt phosphate, cobalt lithium phosphate, groceries, blue and green copper phthalocyanines, metallic and non-metallic azo reds , gold, red, and purple, yellow, mono and diaryluride, naphthol red, pyrrolo-pyrrole, anthranquinone, thioindigo, flavantrone, and other pigments, pigments based on benzimidazolone, dioxazine, perylenes, carbazole violet, periona, isoindoline , and so on. 10 Dyes can be used instead of a pigment or in addition to a pigment. For example, a dye can be used to produce a brighter color than would otherwise be obtained with a composition containing only pigments. The examples of dyes Tools include, without limitation, azo dyes, such as Solvent Yellow 14, Metanil Yellow; anthraquinone dyes, such as Solvent Red 111, Solvent Blue 56, and Solvent Green 3; Xanthene dyes, such as Rhodamine B, Sulfo Rhodamine, Solver Sovent 4, RedAcid 52, Basic Red 1, and Orange Sovente 63; azine dyes, such as indulin and nigrosines; Fluorescent dyes, Brilliant Sulfoflavin (7 amino acid). Orange Sovent 63; azine dye, such as indulin and pigrosines; fluorescent dyes. 25 Brilliant Sulfoflavin (Acid Yellow 7), Sovent Orange 60 (a perinone stain), basic tri enylmethane stains, such as methyl violets and Blue B victoria, and quinoline yellows. Conductive materials include conductive pigments, such as certain grades of carbon black and graphite. Carbon black can function as both a conductive material and a dye. These conductive materials can be incorporated into the coating composition in accordance with the usual methods for incorporating fillers or pigments, which will now be described generally with particular reference to the pigments. The dry pigment can be added, preferably together with the resin, during the composition of the metallic effect nylon material, or it can be pre-dispersed in a carrier resin prior to the composition. The pigment can be dispersed in a carrier resin component, which is preferably a hydrophobic resin component, by a two-step process. In a first step, the pigment agglomerates are broken into smaller particles. In a second step, the air on the surface of the pigment particles is displaced with the resin to "moisten" the pigment to fully develop its hue and color strength. One method for dispersing the pigment in the carrier resin component is to first stir the pigment with granules of the resin and then obtain an intimate mixture by processing the stirred mixture in a roller mill, mixer, Banbury, heavy mixer, or single screw extruder. or double. The resin component is advantageously selected for its ability to disperse a high pigment load and for easy handling. The disperse dye can be, for example, a conventional color concentrate or a liquid color. The color concentrates may include one or more thermoplastic resins and one or more pigments. Examples of suitable thermoplastic resins include, without limit, waxes, polyolefins, homopolymers and copolymers of nylon, and polymers based on styrene. Suitable waxes include naturally occurring waxes such as animal waxes, vegetable waxes, mineral waxes and petroleum waxes, as well as synthetic waxes. Among these, hydrocarbon waxes, such as paraffin waxes, are preferred.; polyalkylene homopolymers and copolymers, especially polyethylene, polypropylene and copolymers of alkenes having from 2 to 10 carbon atoms, particularly copolymers of ethylene with alkenes having from 3 to 10 carbon atoms, especially copolymers with propylene or butylene; microcrystalline waxes; carnauba cers; mountain waxes; Fischer-Tropsch waxes; fatty alcohols; fatty acid derivatives, especially those having from about 12 to about 18 carbon atoms, including stearic acid, palmitic acid, lauric acid, myristic acid, oleic acid, linoleic acid, and castor oil fatty acid, said derivatives including amides and fatty esters of fatty acids; hydrogenated oils, such as hydrogenated castor oil; polyethers, including polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and block copolymers thereof; polytetrahydrofuran; and mixtures of these. Particularly preferred waxes are polyethylene waxes having molecular weights preferably at least about 2000 and preferably less than about 12,000; carnauba waxes; esters of fatty acids; montana waxes and mixtures of these. The pigment may be any of those known in the art, such as those enumerated above, and mixtures of said pigments. The conventional color concentrates can be in the form of granules, cubes, beads, wafers or micro-accounts. The color concentrates can have a pigment load of about 10% by weight to about 80% by weight, typically about 5% by weight. % by weight to about 60% by weight, based on the weight of the color concentrate. Preferably, the color concentrate has a pigment loading of up to about 80% by weight, and preferably at least about 50% by weight, based on the weight of the ^ r color concentrate. The concentration of pigment will vary, depending on the selection of the pigment and carrier. Liquid colors typically have charges pigment of about 10% to about 80% Alternatively, two or more color concentrates or pigments may be added to the metallic effect nylon material during the composition to obtain the desired color. Pigments and color concentrates are readily available from a number of companies, including BASF Corporation, Mt. Olive, NJ; Cabot Corporation, Waltham, MA; Degussa AG, Frankfurt, Germany; ReedSpectrum, Holden, MA; Unifor Color Company, Holland, MI; Americhem Inc., Cuyahoga Falls, OH; and Holland Colors Americos Inc., Richmond, IN. In accordance with the process of the invention, the nylon material, optionally a reinforcing agent, and any additional materials including, without limitation, the additives, color pigments, color concentrates, dyes, or plasticizers, discussed above. , they are added to an apparatus to substantially melt the nylon material and mix the nylon with the other components. Preferably, the apparatus is a single screw or twin screw extruder, such as a 40 mm twin screw extruder. In a preferred embodiment, the extrudator has a melting point temperature of about 270aC and a production rate of about 60kg / min. The nylon resin is preferably added as a granule. Thermoplastic resins are customarily manufactured as granules for further processing or composition. The nylon resin can be added to the composition apparatus as a melt. The nylon resin, together with optional materials such as one or more additives such as UV stabilizers or processing aids, is charged to a hopper and fed into a single screw or twin screw extruder. A thermal stabilizer such as a hindered phenol and a stabilizer containing organic or inorganic phosphorus may be included. The dry pigment or colored concentrate, if used, should be charged together with the nylon resin to ensure homogeneous mixing. A hot feed of the reinforcing agent, particularly fiber reinforcing agents, and, optionally, impact modifier can be introduced into the extruder melting zone. The flake pigment and optionally, as described above, mineral reinforcing agent, is added as a hot feed at a point when the nylon melts substantially. The hot composition melt is then mixed for an additional necessary time to achieve a relatively uniform distribution of the flake pigment in the polyamide matrix. In a preferred embodiment, the metallic effect flake pigment is dry mixed with a mineral reinforcing agent, in particular with wollastonite, mica, solid idrio beads, or hollow glass beads, and then this mixture is used as a hot feed as described in the foregoing. The mixing of the metallic effect flake pigment and the mineral reinforcing agent is preferably carried out under low cutting conditions, for example, by stirring in a drum mixer, to avoid as much as possible, bending or breaking the pieces of flake pigment. Mixing with the mineral reinforcing agent is useful in cases where the flake pigment, such as aluminum pigment, would tend to bridge or form lumps in the feed hopper, as the mineral reinforcing agent tends to improve the capacity of fluidity of the feeding. It is also beneficial to mix the metallic effect pigment with a mineral reinforcing agent when it would otherwise be difficult to measure an appropriate amount of flake pigment due to the low amount of flake pigment used, for example, when feeding equipment is used. type of conventional auger. The metallic effect flake pigment can be added in an exit port after the initial hitting blocks in the extruder melting zone. The material extruded from the die can be cooled, for example in a water bath, and then granulated according to customary methods. In the case of a nylon resin that is suscele to yellowing, the extruded material is preferably rapidly cooled to a temperature below the melting point scale, preferably at a temperature below about 150eC. The granule can then be used to form a final article by any method known in the art to form thermoplastic resins. The term "granules" is understood and used in the present to encompass various geometric shapes, such as squares, trapezoids, cylinders, lenticular configurations, cylinders with diagonal faces, flakes, lumps and substantially spherical shapes including a powder particle or a sphere of larger size. Alternatively, the hot composition melt can be formed directly towards the desired article after the addition of the metallic effect flake pigment. For example, the melt can be extruded as a sheet instead of as the strands that are granulated. The composition melt can also be mixed in a heated appliance and then introduced towards a mold of the desired configuration to cool and solidify to the desired configuration. The method of the invention provides a metallic effect nylon material With improved metallic appearance and clarity compared to materials that can be produced by previously known methods. Additionally, when gloss is employed (ie, metallic effect scale pigment of substantially uniform size and configuration.), The effect polyamide materials The metal of the invention can be molded into complex configurations that have a bright and uniform metallic effect. The metallic effect nylon material of the invention can be formed into articles according to any of the known methods in the branch for thermal fusion processing of thermoplastic resin compositions. For example, compression molding, vacuum molding, injection molding, thermoforming, blow molding, calendering, casting, extrusion, filament winding, rolling, rotational or filling molding, transfer molding, casting or contact molding, stamping , and combinations of these methods can be used with the metallic effect nylon materials formed by the present methods. The metallic effect nylan materials of the invention can be formed into any of the articles generally made with thermoplastic resins. Among the many possibilities, without limit, are chair bases, automotive components including door handles, air intake manifolds, cylinder head covers, engine compartment covers, mirror housings, decorative auto parts, power tool housings; and extruded sheets that can be used, for example, to packaging or thermoforming, power tool bases, automotive engine covers, toys and containers for cosmetics. The invention is further described in the following examples. The examples are merely illustrative 5 ^ 3F and in no way limit the scope of the invention as described and claimed. All parts are parts by weight, unless noted otherwise. Examples 1 and 2 of the invention are prepared in accordance with the following Method of the Invention using the amounts of materials shown in Table I.

Method I: Method of the Invention 0 Nylon-6, cut fiberglass, Organox 1098, Irgafos 168, sodium hypophosphite, and dyes are mixed and fed into an open port at the beginning of a twin screw extruder. Alu * Flake aluminum pigment and wollastonite ore are mixed dry under low shear conditions and loaded into a feed hopper of a borehole type feeding apparatus attached to the side gate beyond the initial kneaded blocks in the melting zone of the extruder. The aluminum pigment mixture is then metered into the molten nylon mixture in the melting zone. The extruded product cools and granulates. Comparison Examples A-C are prepared according to the following Comparison Method using the amounts of materials shown in Table 1.

Method A: Comparison Method Null-6 and aluminum pigment Álu * Flake are mixed dry under low cutting conditions, using a little mineral oil to make the pigment adhere to the nylon granules. The mixture of nylon and aluminum pigment, cut glass fiber, Irganox 1098, Irgafos 168, sodium hypophosphite and dyes are then mixed and fed into an open port at the beginning of a twin screw extruder. The extruded product is cooled and granulated.

Evaluation of the Composite Materials The composite nylon materials prepared in accordance with the above methods were molded in a 100-tonne Engel molding machine at 275sc in test plates of approximately 4.3 cm x 9 cm x 2 cm. A color-view8 * 119 Byk-Gardner Spectrophotometer was used to determine the color in accordance with the color scale L *, a *, b * (CIELAB) using illumination D-65. The results are shown in Table y.

Table 1 All ingredient amounts listed are parts by weight. INGREDIENTS Example 1 Example 2 Example A comparative nylon 61 (remainder) cut glass fibers2 15 15 15 wolastonite mineral3 2 2 0 Irganox 10984 0.3 0.3 0.3 Irgafos 168s 0.1 0.1 0.1 Sodium hypophosphite 0.05 0.05 0.05 Kronos 2220 0 0.3 0 Yellow Filamid R 0 0.014 0 Red Filamid GR 0 0.003 0 Alu * Flake .0046 2 2 2 Method 1 (food- 1 (hot food) hot) hot) L *, a *, b * 50.9, -0.8, 0.8 54.9, 0.6, 43.6, 12.8 -0.9, -0.7 Appearance light brown color light blue khaki with dark gray with shimmer effect with metallic effect memetonic gloss mepronunciado medium a diode, paired pronunpattern and metal flake pattern paescama flake of metal ma fine defimetal well something not defined defined lar 1. Ultramid (B) B3, available from BASF Corporation, Mt. Olive, NJ. 2. PPG 3540, available from PPG Corp., Pittsburgh, PA. 3. 10 Wollastocoa, available from Nyco Minerals, Inc., Willsboro, NY 4. Phenolic antioxidant available from Ciba-Geigy Corporation, Tarrytown, New York 5. Phosphite co-stabilizer available from Ciba-Geigy Corporation, Tarrytown, New York 6. available from Glitterex Corp. , Cranford, NJ As illustrated by the Examples, unexpected and significant improvements and appearance of metallic color and gloss are obtained using the method of the invention.

The invention has been described in detail with reference to the preferred embodiments thereof. It should be understood, however, that variations and modifications may be made within the spirit and scope of the invention and the following claims.

Claims (19)

CLAIMS:

1. - A process for making metallic effect nylon materials, comprising the steps of: (a) heating a nylon material to 5 produce a substantially melted nylon material; and ß (b) adding a portion of metallic effect flake pigment to the substantially melted nylon material; 10 { c) solidifying the substantially melted nylon material to produce a metallic effect nylon material.

2. A process according to claim 1, wherein the portion of flake pigment further includes a mineral reinforcing agent.

3. A process according to claim 2, wherein the mineral reinforcing agent is selected from the group consisting of wollastonite, micas and solid and hollow glass beads.

4. A process according to claim 1, wherein the flake pigment is a metal flake pigment.

5. A process according to claim 4, wherein the metal flake pigment 25 is a gloss.

6. A process according to claim 5, wherein the brightness is of a rectangular or square configuration with an edge length of about 0.05 to about 1.0 mm.

7. A process according to claim 6, wherein the brightness is aluminum brightness.

8. A process according to claim 6, wherein the gloss has scales 10 individual of a substantially uniform size.

9. A process according to claim 4, wherein the metal flake pigment contains less than about 1% by weight of material that is less than about 50 microns in length, ^ 15 lP?

10. A process according to claim 1, wherein the nylon material comprises nylon-6 or n-lll-6, 6.

11. A process according to claim 1, wherein a member selected from From the group consisting of spherically hindered phenolic compounds, phosphorous acid, hypophosphites and mixtures thereof, it is added to the metallic effect nylon material.

12. A process according to claim 25, wherein at least one color pigment is added to the metallic effect nylon material.

13. A process according to claim 1, further comprising a step of forming a metallic effect nylon material towards an article.

14. A nylon material of metallic effect formed by the process of claim 1.

15. A nylon material according to claim 14, wherein the aluminum flake material is an aluminum luster.

16. A nylon material according to claim 15, wherein the gloss is of a rectangular or square configuration with an edge length of about 0.05 to about 1.0 mm.

17. A nylon material according to claim 15, wherein the gloss contains less than about 1% by weight of material less than about 50 microns in length.

18. An article according to claim 13, wherein the article is a molded piece, fiber or film.

19. An article according to claim 13, wherein the article is selected from the group consisting of intake manifolds, cylinder head covers, engine covers, 25 wheel covers, tool boxes, and protective helmets. 10 acJ.5 20 25