MXPA98003517A - Improved process to produce thermoplastic resins manufactured according to specification - Google Patents

Abstract

The present invention describes a method for customizing a thermoplastic resin, in which a thermoplastic resin body is at least partially coated with a molten thermoplastic coating composition containing an additive component and a polymer component. The thermoplastic resin body is at a temperature that is higher than the initiation temperature of the melt processing range of the coating composition. After the coating is applied, the resin body is cooled to solidify the coating composition. Customized thermoplastic resins can be produced more efficiently using the current method than through traditional methods. Customized thermoplastic resins produced according to the invention can be heated above the start temperature of the melt processing range of the resin body, can be mixed to form a substantially uniform mixture and can be formed in an art.

Description

IMPROVED PROCESS TO PRODUCE THERMOPLAS ICAS RESINS MANUFACTURED ACCORDING TO SPECIFICATIONS • Field of the invention The present invention relates to colored thermoplastic resins which are useful for molding articles. In particular, the invention relates to thermoplastic resins manufactured according to specifications, having a thermoplastic resin body, or a base jB resin, coated with a layer of a thermoplastic coating composition of the bottom melting point. The composition of the coating consists of a polymeric component and at least one additive, preferably a dye or pigment and particularly preferably an additive not present in the composition of the body of the thermoplastic resin. In a preferred embodiment, the coating contains as an additive a pigment that is dispersed in the polymeric component. The thermoplastic resin manufactured according to specifications or customized is formed into an article by melting or mixing together the thermoplastic resin body and the thermoplastic coating compositions and extruding, molding or otherwise shaping the combination into the article. BACKGROUND AND SUMMARY OF THE INVENTION • Thermoplastic resins are formed into multiple kinds of articles, for example, by extrusion molding, thermoforming and compression processes, thermoplastic resins are usually made as granules or powders that can be ship with ease and that can be easily and conveniently handled during the formation of the desired items or can be stored for further processing. It is more economical to manufacture the thermoplastic resins as granules in a continuous extrusion process in which the granules are compounded to meet the requirements of multiple uses. However, it is usually the case that a thermoplastic resin must be specially formulated or customized for a specific use or application, such as coloration processes obtainable when molding, for example, including special additives for this use, such as pigments for achieve a specific color or a stabilizer package that meets the specific use requirements.

In particular, the thermoplastic resins can be customized to include certain pigments and / or dyes. It is often desirable that the manufactured item have a specific color. A specific color can, for example, improve the aesthetic appearance of the item or can even serve to help identify the particular brand • or the manufacturer. However, the personalization of the color or additive packages of the thermoplastic resins can present 5 problems. Although general purpose thermoplastic resin, or base resin, can be produced by continuous extrusion operations, colored thermoplastic resins or thermoplastic resins with special additive packages are usually needed in much smaller quantities that are relatively expensive In its production, manufacturing, especially post-production cleaning, is an extremely intense task, and the processing equipment (such as mixers, feeders, extruders and granulation equipment) must be perfectly cleaned after each specific color or color. custom mix to avoid contamination of the thermoplastic resins that will later be produced in the equipment.The cleaning process requires a significant period of interruption in the equipment during which no material must be manufactured, increasing the manufacturing costs of the specialized product. In an alternative way, the colored articles have been produced by combining dry thermoplastic resin without color with a color concentrate (also known as a color masterbatch) which is known in the art as a "salt and pepper mixture". The thermoplastic resin and color concentrate used for these combinations are usually granules or 5 pieces of similar size. The color concentrate is usually a minor amount by weight of the mixture, usually only up to about 5 'by weight, and often much less. The salt and pepper mixture is then introduced directly into the molding or forming equipment used to produce the final article. The melt mixing of the uncolored resin and the color concentrate should be carried out in the molding or forming equipment. However, this process may result in color variations from one piece to another, or even in areas within. of the same piece, due to incomplete mixing, particularly for low mixing ratios of the? color. The segregation of particular additives during packaging and transportation must also be experienced by dry blends and contributes to the lack of homogeneity in the final formed articles. In a method related to the use of a salt and pepper mixture it is possible to introduce plates and liquid colors into the nozzle of an injection molding extruder or other forming equipment. This method also has some disadvantages. First, is it possible that the manufacturer needs complex dosing equipment for f? produce a uniform coloration. Secondly, this method is similar to the salt and pepper method in that the dye material and the colorless resin are introduced practically separately, remaining at the expense of perfect mixing in the forming equipment before the article is finally formed. Incomplete mixing and color variations can be easy. Gose et al., In U.S. Patent No. 5,443,910 and related patents, disclose, the application of certain processing additives, stabilization or other functional polymeric additives to the polymer particles by spraying the particles with an aqueous emulsion of the polymeric additive The emulsion includes an emulsifiable wax (with acid function), surfactant, an additive base and water.This method of customizing the thermoplastic resins, however, has some disadvantages. First, the inclusion of a base compound in the applied material can give rise to unwanted coloration or color deviations, for example, Goce et al., Indicate problems when potassium hydroxide or sodium hydroxide is used. It is also well known that in some systems discoloration can occur from amines. Secondly, the water of the emulsion or the combination of water and base presents problems for hydrophilic resins. In addition, it may be desirable on some occasions to exclude the surfactants from the thermoplastic resin. Finally, the method of application of the emulsion has disadvantages which are inherent in the process, for example, that the applied layer of the emulsion should be dried and the emulsion should be stored and used under carefully maintained conditions to avoid destabilization and separation. Sharma, in U.S. Patent No. 5,300,256 and 10 related patents, also describe the application of an additive to a polymeric particle from an aqueous medium. Sharma describes the handling and storage problems described by Gose and provides a solid, two-phase additive system that can be dispersed in water just before application. The polymeric additives used by Sharma must be melted at a temperature not higher than 100 ° C and may include hydrophilic polymers such as low molecular weight polyolefins with carboxylic moieties. The additives again contain water and are further diluted with water and applied as an aqueous emulsion, still with concomitant problems such as those already mentioned. It is also known to prepare color concentrates by a method in which a mixture is combined together of pigment, low molecular weight polyethylene wax and thermoplastic polyolefin granules. The pigment and the wax are included in relatively high levels, for example, about 40% by weight of the mixture. The wax that disperses the pigment forms a layer on the polymer granules. This masterbatch is combined with unmodified basic polyolefins to form a "salt and pepper" mixture. The high pigment charge and the dispersing wax are required in the masterbatch to achieve the desired final pigment loading in the salt and pepper mixture. These mixtures containing the masterbatch present the same problems already described. In addition, the relatively thick coating of the wax on the granules is undesirable for the reason that these thick coatings tend to split and flake easily, which could give rise to segregation and inhomogeneity in the molded articles, as well as dust problems in production. • In this way, it would be desirable to provide a custom thermoplastic resin that overcomes the disadvantages of those produced by the methods already described. We have now discovered a novel method for preparing custom thermoplastic resins in which the pieces, usually granules, of thermoplastic resins are coated with a coating that consists of a polymer component and an additive component. The polymeric component of the coating has a melting point, softening point or glass transition temperature lower than the melting point, softening point or glass transition temperature of the thermoplastic resin body. The melting point, softening point or glass transition temperature, already mentioned (or other temperature or temperature range where the resin begins to soften or flow), of a specific resin or resin composition may be, for convenience, called the initiation temperature of the fusion processing range. Those skilled in the art will appreciate that the term "initiation temperature for the range of the melt processing" is used herein for convenience, and may indicate a single different temperature or a range of temperatures. In relation to range differences, one can use the difference of the upper, lower or average temperature within a range; the preferred term employs the most significant temperature separation in the application under consideration. In a preferred embodiment, the coating is a color concentrate containing a polymer component and one or more pigments, optionally with other additives. In a process for producing the custom thermoplastic resins of the invention, the thermoplastic resin body or part is brought into contact with the coating at a temperature at which the composition of the coating is a melt. The pieces or coated resin granules are cooled to solidify the coating in a layer on the thermoplastic resin body. In a preferred embodiment a substantially uniform thickness of an outer layer of custom coating is applied. Coated resin parts or granules are easily handled and can be formed into articles Using the same processes and in the same way as the resin granules that have had the color or other additives mixed in an integral manner, the color concentrate or other custom coating composition is covered over the resin 15 after the piece of resin has been formed.The custom thermoplastic resins of the invention in this way can be produced in an easy to clean equipment and do not require time to paralyze the equipment used to manufacture the body of thermoplastic resin, giving as results in a much more versatile and economical process. In addition, because each granule or other body of the thermoplastic resin = is in intimate contact with the pigment or additive necessary to produce the desired custom resin, defects such as lack of homogeneity are avoided, which is especially evident when included. color. In addition, surfactants, water, amines and # resins with hydrophilic functionality used in the prior art compositions are no longer necessary for the coatings of the present invention. In particular, the present invention provides a custom thermoplastic resin having a thermoplastic resin body and an outer layer of the thermoplastic coating, covering at least a part of the body, containing a polymeric component and an additive component. It is particularly preferred that the additive be a pigment.

DETAILED DESCRIPTION The custom thermoplastic resins of the invention have a thermoplastic resin body and an outer layer of thermoplastic coating that at least partially covers the body. The coating includes a polymer component having an initiation temperature for its melt process range that is lower than the melt process range initiation temperature of the thermoplastic resin body. The coating also includes an additive component that contains at least one additive. It is preferred that the additive component contains at least one colorant or pigment as the additive or as one of a plurality of additives. The thermoplastic resin body is preferably a granulate. The thermoplastic resins are custom-made as granulates for further processing in the desired article. The term "granulate" is understood and used herein to comprehend various geometric shapes, such as square shapes, trapezoids, cylinders, lenticulars, cylinders with diagonal faces, flakes, bits and substantially spherical shapes that includes a powder particle or a Larger size sphere. Although thermoplastic resins are often sold as granules, the resin can be in any shape by size suitable for use in the equipment that is used to form the final article. The thermoplastic resin body is preferably a granule. Thermoplastic resins are custom-made as granules for further processing > 'in the desired article. The term "granules" is understood and used herein to comprehend various geometric shapes, such as square shapes, trapezoids, cylinders, lenticulars, cylinders with diagonal faces, scapes, bits and substantially spherical shapes that includes a powder particle or a sphere of larger size. Although thermoplastic resins are often sold as granules, the resin can be in any shape by size suitable for use in equipment that is used to form the final article [sic]. The thermoplastic resin body can contain almost any suitable thermoplastic resin to be formed into articles by thermal processes, molding, extrusion or other of these processes that can be employed in the methods of the invention, with the proviso that the thermoplastic resin of the body resin should have a # 10 initiation temperature for its melting process range higher than the melting process initiation temperature of the polymer component of the outer coating layer. For example, and without limitation, it is possible to use advantageously the following thermoplastic materials: acrylonitrile-butadiene-styrene (ABS), acetal resins such as polyoxymethylene, acrylics, acrylonitrile (AN), allyl resins, * cellulosics, epoxies, polyarylether ketones , polyether ether ketones (PEEK), phenolics, polyamides (nylon), including 20 polyamide-6, polyamide-β, 6, polyamide-6, 10 and others; polyimides, polyamide-imide resins, polyolefins (TPO), including polyethylene, polypropylene and polybutylene homopolymers and copolymers; polycarbonates; polyesters, including polyalkylene terephthalate = as may be polybutylene terephthalate (PBT) and polyethylene terephthalate (PET); polyimides and poly 'ether imides; polyphenylene oxide; polyarylene sulfites, such as polyphenylene sulfite; polyarylene sulfides such as polyphenylene sulfide; polyvinyl resins, including 5 polystyrene (PS) and styrene copolymers such as styrene-acrylonitrile copolymer (SAN) and acrylic-styrene-acrylonitrile copolymer (ASA), polyvinyl polymers including polyvinyl chloride (PVC) and polyvinyl chloride, phenylene; polyurethanes (TPU) and polysulfones, including ? iF 10 polyarylether sulfones, polyether sulfones and polyphenyl sulfones. Mixtures of block copolymers of 2 or more resins can also be used. Preferred materials for the thermoplastic resin body include polyesters, polyamides, polyolefins, polystyrenes and copolymers of polystyrene, polyacetals, polycarbonates, acrylics, polyether ether ketones and mixtures thereof. Polyesters, polyamides, polystyrenes and polystyrene copolymers and mixtures thereof are especially preferred. The thermoplastic resin body of the present custom thermoplastic resins may also contain a fibrous material. These fibers can be included as reinforcing agents. Useful fibers include, without limitation, glass fibers, carbon fibers and graphite, polymeric fibers including aramid fibers, gold filaments, ceramic fibers, metal fibers, asbestos fibers, beryllium fibers, silica fibers, silicon carbide fibers and others. The fibers can be conductive and such conductive fibers, for example carbon fibers or conductive metal fibers, can be used to produce articles for conductive or static charge dissipation applications or the EMI protective cover. Among these, glass fibers, carbon fibers and aramid fibers are preferred. The methods of preparing thermoplastic resins that include these fibers are well known in the art. In one method, bundles of cut glass fibers are fed into the melting zone of the extruder that is used to form the thermoplastic resin body, for example, by introducing the bundle or bundle of fibers through a feeder port. The custom coating or outer layer covers at least part of the thermoplastic resin body, in a preferred embodiment, the thermoplastic resin body is substantially encapsulated by the coating. By "substantially encapsulated" we mean that at least about three quarters of the surface of the thermoplastic resin body is coated, and preferably at least about 9 tenths of the resin body is coated. It is particularly preferred that the coating covers substantially the entire resin body. The coating of the custom thermoplastic resin has a thickness that will give rise to the desired weight ratio of the coating composition to the composition of the thermoplastic resin body when the two are melt combined during the formation of the final article. The weight ratio of the coating to the thermoplastic resin may, in general, be in the range of at least about 0.1% by weight and up to about 10% by weight, based on the weight t ~ 10 of the custom thermoplastic resin. It is preferred that the coating be at least about 0.5% by weight and up to about 5% by weight, based on the weight of the custom thermoplastic resin. In this way, the thickness of the coating will depend on such factors as the surface area of the thermoplastic resin body that is coated and the concentration of the additive and additives in the coating compared to the desired concentration in the final mixture of the resin body. and the coating. For a common cylindrical granule, the coating can be up to an average of about 300 microns thick. In a preferred embodiment, the average thickness of the coating for these granules can be at least about 10 microns and up to about 200 microns. The coating contains a polymer component and an additive component. The polymer component consists of one or more resins or polymers. The examples of * Suitable materials for the polymer component include, without limitation, the thermoplastic materials already mentioned as suitable for the resin body, waxes 5 and mixtures thereof. In a preferred embodiment, the polymer component is a crystalline material. When the thermoplastic resin body contains a water-sensitive material, such as a polyamide, it is preferred that the coating contain a hydrophobic resin component as its polymer component. It is contemplated that a hydrophobic polymer-based coating, such as a wax-containing coating, will slow down or prevent the reabsorption of water in a hydroscopic resin body [sic]. Examples of materials suitable for the hydrophobic resin component include, without limitation, waxes and wax mixtures. Waxes are usually defined as materials that are solid at room temperature, have relatively low melting points and can soften when heated and harden upon cooling. Useful waxes include, without limitation, natural waxes such as animal waxes, vegetable waxes, mineral waxes and petroleum waxes, as well as synthetic waxes. Preferred among these are hydrocarbon waxes, such as paraffin waxes; as polymers and copolymers of polyalkylene, 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 of ethylene with propylene or butylene; microcrystalline waxes; carnauba waxes; ozokerite or lignite wax; Fischer-Tropsch waxes; acid grades, especially those having from about 12 to 18 carbon atoms, including stearic acid, palmitic acid, lauric acid, myristic acid, oleic acid, linoleic acid and tallow oil fatty acids and fatty acid derivatives they include fatty acids dimers, fatty amides, fatty acid soaps - such as zinc stearate and fatty acid esters; hydrogenated oils such as hydrogenated castor oil; polyethers including polyalkylene glycols such as polyethylene glycol, polypropylene glycol and block copolymers thereof; polytetrahydrofuran and mixtures thereof. Especially preferred are polyethylene waxes containing molecular weights preferably of at least about 2000 and preferably below about 12,000; polypropylenes, ethylene copolymers, oxidized polyethylenes, lignite ester waxes, polystyrene and styrene copolymers, carnauba waxes, fatty acid esters and mixtures thereof. Other suitable polymeric materials include polystyrenes and polystyrene derivatives, polyvinyl polymers including chlorinated polyvinyl polymers such as polyvinyl chloride and mixtures thereof. The additive component of the coating includes at least one additive. Examples of suitable additives include, without limitation, plasticizers, thixotropes, optical brighteners, anti-oxidants, UV absorbers, hindered amine light stabilizers, hindered amide light stabilizers, thermal stabilizers, flame retardants, pigments, dyes, conductive materials , non-fibrous reinforcers and particulate fillers such as talcum, shock modifiers such as ionomers, maleinized elastomers and synthetic natural rubber particles, processing aids such as lubricants, mold releasing agents, and glidants, fragrances, antifoaming agents, anti-oxidants, antistatic agents, antimicrobials, biocides and others. Surfactants and acids or bases that are used to salt ionic resins or polymers are not consider additives within the scope of the invention. In a preferred embodiment, the additive component of the coating contains at least one pigment or dye. Preferably, the pigment is present in an amount of up to about 8. by weight and, especially, to about 4% by weight, based on the weight of the custom thermoplastic resin. Suitable pigments are black, white or colored pigments, as well as extenders. Examples of useful pigments include, without limitation, titanium dioxide, zinc oxide, zinc sulphide, barium sulfate, aluminum silicate, calcium silicate, carbon black, black iron oxide, black copper chromite, yellow iron oxides, red iron oxide, brown iron oxides, ocher, - siena, dark ocher, hematite, limonite, mixed iron oxides, oxides of chromium, prussian blue (ammonium ferrocyanide), chrome green, chromium yellow, manganese violet, cobalt phosphate, lithium and cobalt phosphate, groceries, copper phthalocyanines, blue and green, azo metallized and non-metallized reds, gold, red and purple quinacridones, 15 yellow mono-and diaryluro, naphthol red, pyrrolo-pyrrole, anthraquinone, thioindigo, flavantrone and other tub pigments, pigments based on benzidimidazolone, dioxazine, perylenes, carbazole violet, perinone, isoindoline and others. 20 The dyes can be used in place of a pigment or in addition to the pigment. For example, it is possible to use a colorant to produce a brighter color than would otherwise be obtained with a composition containing only pigments. Examples of dyes Useful includes, without limitation, azo dyes, such as Solvent Yellow 14 and Metanil Yellow; anthraquinone dyes such as Solvent Red 111, Solvent Blue 56, and Solvent Green 3; xanthan dyes, such as Rhodamine B, Sulfo Rhodamine, Sovent Green 4, Acid Red 52, Basic Red 1, and Sovent Orange 63; azine dyes such as indulin and nigrosines; fluorescent dyes, Brilliant Sulfoflavine (Acid Yellow 7), Sovent Orange 60 (a perinone dye), basic triphenylmethane dyes, such as methyl violet and Victoria Blue B and yellow quinoline. Conductive materials include conductive pigments, such as certain grades of carbon black and graphite. Carbon black can function as a conductive material and as a colorant. These conductive materials can be incorporated into the coating composition according to the normal methods for incorporating fillers or pigments, which will now generally be described by making specific references to the pigments. The pigment can be dispersed in the carrier, which is the polymeric component or one of the resins of the polymer component, by a two-step process. In a first step, agglomerates of the pigment are broken into smaller particles. In a second step, the air at the surface of the pigment particles is displaced with resin to "soak" the pigment, thereby fully developing its hue and color intensity. A method for dispersing the pigment in resin or polymeric component is to first spin the pigment with the granules of the resin in a drum and then obtain an intimate mixture by processing the mixture in a roller mill, a Banbury mixer, intensive mixer or extruder. of one or double helix. The dispersed colorant may be a conventional color concentrate or a liquid color. If a # 10 liquid color, this should be used at a fairly low level to be encapsulated by the polymer component so that the coating is solid at room temperature. The conventional color concentrates may include one or more thermoplastic resins and one or more pigments. Examples of suitable thermoplastic resins include, without limitation, waxes, as the examples mentioned in the foregoing; polyolefins, polystyrenes and polyvinyl chloride resins. The thermoplastic resin of the color concentrate forms, or forms part of, the polymer component of the coating. The pigment may be any of those known in the art, such as those mentioned above and pigment mixtures. The conventional color concentrates may be in the form of granules, cubes, beads, wafers or microspheres. The colored concentrates can have a pigment loading of from about 10 ° by weight to about 80 ° by weight, usually from about 30 ° by weight to about 60% by weight, based on the weight of the concentrate color. It is preferred that the color concentrate has a pigment loading of up to about 80% by weight, and preferably at least about 50% by weight. The concentration of the pigment will vary depending on the selection of the pigment and carrier. Liquid colors usually have pigment charges from about 10O to up to about 80'W. It is particularly preferred that the coating contains at least one color concentrate. The color concentrate can be prepared according to known means, with at least one pigment and optionally with additional additives as antioxidants, and can be used as the coating during the preparation of the custom resins of the invention, in an alternative way , two or more color concentrates can be combined to obtain the desired color and can be applied as the coating of the invention. Colored concentrates are commercially available from several companies, including ReedSpectrum, Holden, MA; Unifor Color Company, Holland, MI; Americhem Inc., Cuyahoga Falls, OH; and Holland Colors Americas Inc., Richmond, IN.

The thermoplastic resin body may also include one or more additives. When the same additive is present in the thermoplastic resin body composition and in the thermoplastic coating layer, then the coating composition can be used to increase the amount of the additive to customize the concentration of this additive over that of the base resin. When the additive that is present in the coating is not present in the thermoplastic resin body composition, then the addition of a coating layer can be used to customize the granulate including an additive that is not found in the body's 1-resin. . The coating preferably includes at least one additive that is not included in the body of the thermoplastic resin. In a particularly preferred embodiment, the thermoplastic resin body has no pigment-that is, it contains substantially no pigment or dye-and the coating contains at least one pigment or dye. The polymer component of the coating must have an initiation temperature for its melt processing range that is below the melt processing range initiation temperature of the thermoplastic resin body. In this way, the melt of the coating containing the polymer component can be applied as a melt to the composition of the thermoplastic resin body while the latter is solid or substantially solid. The initiation temperature of the melt processing range of the polymeric component of the coating is preferably above about 20 ° C and more preferably is above about 60 ° C and, even more preferably, is at least about of 80 ° C. the initiation temperature of the melting process range of the polymeric component of the coating preferably has an initiation temperature for its melt processing range of at least about 20 ° C below and, even of the initiation temperature for the melting process range of the thermoplastic resin body . Yes the customized thermoplastic resin granules are to be dried using a dryer, then the melting process range of the polymer component is preferably above the dryer temperature. In a preferred embodiment, the coating that encapsulates the granules of The thermoplastic resin is chosen to prevent or slow down the absorption of water so that a drying step before the formation of the desired article is unnecessary is unnecessary. The initiation temperature of the process range of the melting of the coating composition containing The polymeric component must be below the starting temperature of the melting process range of the thermoplastic body composition. A lower initiation temperature of the melt process range can be obtained using a different kind of polymeric material, for example, using a nylon composition for the thermoplastic resin body composition and a polyethylene composition as the coating composition or using resins with the same class of polymeric material that have different process temperature ranges due to different molecular weights, plasticization with lower melting point materials or using different monomers during resin synthesis that tend to reduce their processing temperature range . For example, the composition of the thermoplastic resin body may contain a polyolefin resin and the coating composition may also contain a polyolefin, but with the polyolefin of the coating having an initiation temperature lower than the melt processing range. The thermoplastic resin or the resins that are included in the polymer component of the coating preferably have no detrimental effect on any of the resins of the thermoplastic resin body composition. For example, the polymeric component should not contain resin that is incompatible with a resin of * the composition of the thermoplastic resin body at the expected processing temperatures at which the custom resin will be used to form the final article 5. An example of a damaging interaction would result from a combination of polyvinyl chloride and nylon in which the production of HCl from the PVC during processing would cause the degradation or discoloration of the nylon. A second example of an undesirable interaction * 10 would be a transesterification or transamidation between a nylon and a polyester. Another example of an undesirable interaction would be the stratification of two resins during the step of forming the final article due to incompatibility. Although the use of a combination of resins having these interactions is not preferred, it is still possible to use an otherwise undesirable resin in the coating composition in small amounts, such as less than about 5% by weight and especially less than about 3 'by weight, based on the total weight of the custom thermoplastic resin. For convenience, but not limitation, custom thermoplastic resins of the present invention, in general, will be described in terms of a grainy form, although other forms are contemplated as has mentioned.

In a preferred process for producing the custom thermoplastic resin of the invention, the unmodified thermoplastic resin and, optionally, one or more additives, such as UV stabilizers or processing aids, are charged to a hopper and fed to a a single-screw or twin-screw extruder. A hot feed of glass or mineral reinforcements and, optionally, shock modifiers can be introduced into the melting zone of the extruder, if you want. The extruded product from the nozzle can be cooled, for example, in a water bath and then granulated according to the methods customary to produce the thermoplastic resin body. In the case of a thermoplastic resin which is susceptible to yellowing, the extruded product is preferably cooled rapidly to a temperature below the melting point range, preferably at a temperature of about 150 ° C below and, preferably, at a temperature of not less than about 60 ° C. In general, coating compositions having low melt processing ranges are preferred for thermoplastic resins that tend to yellow. The granules based on hydroscopic thermoplastic materials [sic] must be dried before being coated.

After forming, the granules can then be f coated by the different methods. In one method, the granules are placed in a container with a coating composition while the granulate is still at a temperature above the initiation temperature of the melt processing range of the coating composition. In this case, the composition of the coating may already be melted or melted by the heat of the granulates or by heat # 10 applied externally to the container. For example, without limitation, the coating can be introduced into the container as a powder when the container is to be melted. It is particularly preferred if the coating composition is not melted before being brought into contact with the granulate, that the coating composition has an initiation temperature for its melt processing range which is below the temperature of the granulate in the container, which will usually be above 60 ° C and up to about 150 ° C. He The content of the container is mixed, for example, by rotating in a drum or with a blade blade or a propeller blade. Additional heat can be applied to the container when necessary to obtain the desired coating of the granulate with the composition of the coating. The coated granulate is then cooled using a cooling jacket with stirring of the # contents of the container, direct application of cooling air to the granulate in the container or to the granulate after it leaves the container or by contacting the granulate with a non-reactive refrigerant such as liquid nitrogen or dry ice. It is possible to introduce the granulate in a drum or stir it during cooling so that it does not agglutinate. The granulate is preferably cooled to a temperature at which the coating hardens to easily remove the granulate from the container and can be further cooled when necessary before packaging. In a second method to apply the coating to the granulate, the granulate, after leaving the granulator and While still hot, it is transported to an area where the coating composition is applied as a melt (ie without solvent). The composition of the coating can be applied by spraying, as long as the composition is of a viscosity suitable for the spray equipment, or can be applied by powder coating methods. The coating is preferably applied as a hot melt. Although it is not necessary to apply the coating to all the surfaces of the granulate, care must be taken (as in each of the method of applying the coating layer) to apply an adequate amount of the composition of 9F coating so that obtain the desired weight ratio of the coating to the granulate. Overcoating (that is, the composition of the sprayed coating that is not deposited on the granulate) can be collected, remelted and re-sprayed. The composition of the melted coating can also drip onto the granules instead of spraying it. In the second method, the coating composition can also be applied by transporting the * 10 granulate through a melting bath of the coating composition. The granulate can be transported through the molten bath by means of, for example, and without limitation, a conveyor belt or by batchwise immersion, such as in a porous metal basket. It is also possible to allow the granulate to cool completely and then to heat the granulate to a desired temperature again before coating it. This reheating can be achieved with, for example, hot air or radiant heat. In this way, the granulate that The thermoplastic resin body of the custom thermoplastic resins of the invention can be produced and stored for a period of time, then reheated and coated at a later time to form the custom thermoplastic resin.

In some cases, it may be beneficial to cool the granulate below the initiation temperature of the melt processing range of the coating composition. For example, during the processes described above in which the molten coating composition is applied to the resin granulate, it may be possible to use cooled granulate to activate the cooling and hardening of the coating to be applied. It may be desirable to use granulate that is at room temperature or below to increase the thickness of the coating layer that may be applied, or to activate the production of the coated granulate. It is preferred that the granulate be at least about 30 ° C, more preferably at least about 50 ° C, and even more preferably at least about 70 ° C below the starting temperature of the range of the melt processing of the coating composition. In still another method for coating the granulate, the granulate and the coating composition are charged to a fluidized bed reactor, roller mill, ball mill (with the granulate replacing the steel balls), or disperser equipped with a flat impeller, together with the coating. It is also possible to load the granulate and the individual components of the coating of the polymeric component, such as a polyolefin wax and the additive component consisting, for example, of one or more pigments or dyes and / or optionally one or more other additives. . The materials are then processed at a temperature at which the granulate remains solid. This can be achieved by adding the coating or polymer component as a melt, applying heat to the processing vessel after the ingredients are charged, by the heat generated from the friction and shear force of the materials during processing or by any combination thereof. .

After processing for a sufficient time to produce a substantially homogeneous coating on the granulate, the coated granulate is cooled, preferably with stirring or by means of a rotary drum to prevent the granulate from agglutinating as the coating solidifies. The coated granulate, or the custom thermoplastic resin of the invention, can be formed into articles according to any of the methods known in the art for thermal fusion processing of the thermoplastic resin compositions. for example, compression molding, vacuum molding, injection molding, thermoforming, blow molding, casting calendering, extrusion, filament winding, rolling, rotary molding or casting a hollow cast, two-stage molding, stratification molding. or contact, stamping and f combinations of these methods can be used with custom thermoplastic resins formed by the present methods. The custom thermoplastic resins of the invention can be formed in any of the articles generally made with thermoplastic resins. Among the many possibilities are, without limitation, bases for chairs, connectors and electrical boxes, automotive components that include loudspeaker grilles, mirror boxes and fluid tanks, boxes for mechanical tools, components of electrical items such as refrigerator drawers and handles for oven doors, toys such as plastic building blocks, toothbrushes and films or extruded layers. The invention is further described in the following examples. The examples are merely illustrative and in no way limit the scope of the invention as described and claimed. All parts are parts by weight unless otherwise stated. EXAMPLE A coating composition is produced as follows: 35 parts by weight of phthalocyanine blue (Hliogen Blue K 25 7090, available from BASF Corp., Mt. Olive, NJ) is combined with 65 parts by weight of Luwax 61 (dot fusion = 103-111 ° C, available from BASF Corp., Mt. Olive, NJ) in a split hopper kneader, open, for 20 minutes at 150 ° C. The mixture is allowed to cool, is removed from the kneader and then crushed to a coarse powder. A custom thermoplastic resin is prepared as follows: 70 parts by weight of nylon 6 (Ultramid® B3, available from BASF Corp., Mt. Olive, NJ) is composed of 30 parts by weight of chopped glass fibers (3760 chopped strands of PPG Inc., Pittsburgh, PA) in a continuous, double helix extruder, ZSK 40 (Werner &Pfleiderer) at 260 ° C for a throughput of 80 kg / h. Immediately after leaving the nozzle, the strands are run through a 36-inch water bath, after which they are blown with compressed air to remove excess water and then fed through a knife granulator Rotary Scheer. 50 kg of granulate is collected in a 55 gallon metal drum installed to spin the drum. The temperature of the granulate is approximately 120 ° C. 1.5 kg of the coating composition prepared above is added to the drum and the mixture is rotated for a further 10 minutes until the coating composition has uniformly covered the granulate and the temperature of the granulate has cooled to 60 ° C. The coated granulate is dried to a moisture content of 0.08 '? in weight of the granulate.

The custom thermoplastic resin is then molded by injection into ductile bars having a uniform blue coloration and appearance and excellent physical properties. The invention has been described in detail by making and reference to the preferred embodiments thereof. It should be understood, however, that variations and modifications can be made within the spirit and scope of the invention and the following claims.

Claims (50)

1. A method for customizing a thermoplastic resin comprising the steps of: (a) providing a thermoplastic resin body that is at a first temperature; (b) applying, to at least one part of the thermoplastic resin body, a thermoplastic coating composition containing an additive component and a * 10 polymeric component, wherein the composition of the coating has a range of fusion processing and, furthermore, wherein the first temperature is higher than the initiation temperature of the melt processing range of the coating composition; (c) cooling the coated thermoplastic resin to solidify the coating, to produce a custom thermoplastic resin.

2. The method according to claim 1, wherein the composition of the coating consists of a melt.

3. The method according to claim 1, wherein the coating composition consists of a powder.

4. The method according to claim 1, wherein the thermoplastic resin body has a substantially cylindrical shape.

5. The method according to claim 1, further comprising a step of forming the thermoplastic resin body by means of extruding and granulating a thermoplastic resin.

6. The method according to claim 5, further comprising a step of maintaining the temperature of the granulate at or above the first temperature between the granulation step and the coating passage.

7. The method according to claim 5, further comprising the steps of: cooling the granulate below the first temperature after the granulation step 15 and then heat the granulate at the first temperature for the passage of the coating.

The method according to claim 7, wherein the heating step is carried out using a heating means that is selected from the group 20 consisting of dielectric heating, microwave heating, radiant heating, heating with hot air, contact heating and combinations of these.

9. The method according to claim 7, wherein the granulate is cooled to room temperature after the granulation step.

The method according to claim 1, wherein the thermoplastic resin body consists of a polymeric material that is selected from the group consisting of polyesters, polyamides, polyolefins, polyurethanes, polystyrenes and polystyrene copolymers, polyacetals, polycarbonates, acrylics, 10 polyether ether ketone, and mixtures thereof.

The method according to claim 1, wherein the thermoplastic resin body consists of a polymeric material that is selected from the group consisting of polyesters, polyamides, polystyrenes and polystyrene copolymers and mixtures thereof.

The method according to claim 1, wherein the polymer component of the coating consists of at least one member of the group consisting of waxes and mixtures thereof.

13. The method according to claim 1, wherein the polymer component of the coating consists of a hydrophobic material.

The method according to claim 1, wherein the polymer component of the coating contains at least one member of the group consisting of hydrocarbon waxes, polyalkylene homopolymers and copolymers of alkenes having from 2 to 10 carbon atoms , microcrystalline waxes, carnauba waxes, lignite waxes, Fischer-Tropsch waxes, fatty acids having from about 12 to 18 carbon atoms and derivatives thereof, and mixtures thereof.

The method according to claim 1, wherein the polymer component of the coating comprises at least one member of the group consisting of polyethylenes, polypropylenes, copolymers of ethylene with alkenes having from 3 to 10 carbon atoms, Carnauba waxes, fatty acids having from about 12 to about 18 carbon atoms and derivatives thereof, lignite waxes and mixtures thereof.

The method according to claim 1, wherein the additive component comprises at least one member that is selected from the group consisting of plasticizers, thixotropes, antioxidants, UV haulers, optical brighteners, hindered amine light stabilizers, stabilizers light of hindered amides, thermal stabilizers, flame retardants, pigments, dyes, conductive materials, non-fibrous reinforcers, particulate fillers, shock modifiers, elastomers, natural and synthetic rubber particles, lubricants, mold release agents and slip agents, fragrances , anti-foaming agents, anti-oxidants, antistatic agents, antimicrobials, biocides and mixtures thereof.

The method according to claim 1, wherein the additive component consists of at least one pigment.

The method according to claim 1, wherein the polymer component of the coating has an initiation temperature for its melt processing range that is at least above about 20 ° C.

The method according to claim 1, wherein the polymer component of the coating has an initiation temperature for its melt processing range which is at least above about 60 ° C.

The method according to claim 1, wherein the polymer component has an initiation temperature for its melt processing range which is at least above about 80 ° C.

The method according to claim 1, wherein the first temperature is at least about 20 ° C above the initiation temperature of the melt processing range of the coating composition.

The method according to claim 1, wherein the first temperature is at least about 40 ° C above the initiation temperature of the melt processing range of the coating composition.

The method according to claim 1, wherein the first temperature is at least about 60 ° C.

The method according to claim 1, wherein the first temperature is up to about 150 ° C.

The method according to claim 1, wherein the thermoplastic resin body is non-pigmented and further wherein the coating additive consists of at least one pigment.

The method according to claim 1, wherein the thermoplastic resin body comprises at least one additive which is selected from the group consisting of plasticizers, thixotropes, antioxidants, UV absorbers, optical brighteners, hindered amine light stabilizers, light stabilizers of hindered amides, thermal stabilizers, flame retardants, pigments, dyes, conductive materials, non-fibrous reinforcers, particulate fillers, shock modifiers, elastomers, natural and synthetic rubber particles, lubricants, mold release agents and slip agents , fragrances, antifoaming agents, antioxtants, antistatic agents, antimicrobials, biocides, and mixtures thereof.

27. The method according to claim 1, wherein the thermoplastic resin body contains a fibrous material.

The method according to claim 1, wherein the thermoplastic resin body contains at least one material that is selected from the group consisting of glass fibers, carbon fibers, aramid fibers and combinations thereof.

29. The method according to claim 1, wherein the coating comprises at least one color concentrate.

30. The method according to claim 1, wherein the thermoplastic resin body contains a non-pigmented polyamide resin and, in addition, wherein the coating comprises at least one pigment.

31. The method according to claim 1, where the coating is up to about 300 microns thick.

The method according to claim 1, wherein the coating is up to about 10% by weight of the custom thermoplastic resin.

The method according to claim 1, wherein the coating is up to about 5 'by weight of the custom thermoplastic resin.

The method according to claim 1, wherein the additive is up to about 80% by weight of the coating. .

The method according to claim 1, wherein the coating contains up to about 80o by weight of at least one pigment.

The method according to claim 1, wherein the additive component comprises at least one pigment, the pigment being present in an amount of up to about 8% by weight based on the weight of the custom thermoplastic resin.

The method according to claim 1, wherein the additive component consists of at least one pigment, the pigment being present in an amount of up to about 4% by weight, based on the weight of the customary thermoplastic resin.

The method according to claim 1, wherein the polymeric component of the coating is crystalline.

39. The method according to claim 1, wherein the thermoplastic resin body is substantially encapsulated by the coating.

40. The method according to claim 1, wherein the passage of the coating (b) is carried out in a container having the means for mixing.

41. The method according to claim 40, wherein the mixing means is a blade blade.

42. The method according to claim 40, wherein the container having the means for mixing is an extruder.

43. The method according to claim 2, wherein the passage of the coating (b) is carried out by immersing the resin body in the molten coating composition.

44. The method according to claim 43, wherein the resin body is conveyed through the molten coating composition by means of a conveyor belt.

45. The method according to claim 43, wherein the resin body is placed inside a porous container and then immersed in the composition of the molten coating.

46. The method according to claim 2, wherein the molten coating composition is emptied onto the thermoplastic resin body.

47. The method according to claim 2, wherein the molten coating composition is sprayed onto the thermoplastic resin body.

48. The method according to claim 3, wherein the powder coating composition is sprayed onto the thermoplastic resin body.

The method according to claim 3, wherein the powder coating composition is applied to the fluidized bed thermoplastic resin body

50. A method for producing an article, comprising the steps of: (a) providing a thermoplastic resin body that is at a first temperature, (b) applying, to at least a part of the thermoplastic resin body, a thermoplastic coating composition containing an additive component and a Polymer component, wherein the coating composition has a melt processing range and further wherein the first temperature is higher than the melt processing range initiation temperature of the coating composition; (c) cooling the coated thermoplastic resin body below the initiation temperature of the melt processing range of the coating composition to produce a custom thermoplastic resin; (d) heating the custom thermoplastic resin above the initiation temperature of the melt processing range of the resin body; (e) mixing the resin body and the coating composition to form a substantially uniform mixture; (f) forming an article from the mixture. The method according to claim 50, wherein the mixing step (e) is carried out in an extruder. The method according to claim 50, wherein the forming step (f) is carried out by means which is selected from the group consisting of: compression molding, vacuum molding, injection molding, thermoforming, blow molding, calendering, casting, extrusion, filament winding, lamination, rotary molding or a hollow casting, two-phase molding, stratification or contact molding, stamping and combinations thereof.