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Title:
POLYMER SUBSTRATE WITH ADDITIVES AND THERMALLY INDUCED DIFFUSION PROCESS FOR MAKING
Document Type and Number:
WIPO Patent Application WO/1996/032529
Kind Code:
A1
Abstract:
A stabilized and/or modified polymer substrate is prepared by a solvent-free, thermally induced diffusion process. The process features the steps of electrostatically depositing an effective amount of stabilizer and/or modifier additive(s) as a powder onto selected surfaces of the substrate followed by heating the powder to a temperature above the Tg of the substrate and above the melting point of the additives until the powder melts and diffuses into the substrate. Light stabilized polyester or polyamide woven fabrics which are resistant to fading and degradation by light can be made which have utility in seat belt webbing and industrial webbing. Polyester tire cord and polyester or polyamide woven fabrics with enhanced adhesion to various coatings can also be made which have utility in tires and coated fabrics, respectively.

Inventors:
HOPF FREDERICK ROBERT
HORN KEITH ALAN
HEATH RICHARD BIDWELL
Application Number:
PCT/US1996/005094
Publication Date:
October 17, 1996
Filing Date:
April 12, 1996
Export Citation:
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Assignee:
ALLIED SIGNAL INC (US)
International Classes:
B05D1/06; B05D7/02; B60C9/00; C08J7/06; D06M10/00; D06M10/04; D06M23/08; (IPC1-7): D06M23/08; B05D1/06; B05D7/02; C08J7/06
Domestic Patent References:
WO1992015404A11992-09-17
Foreign References:
FR1209311A1960-03-01
EP0608510A11994-08-03
DE2260213A11973-06-14
BE651292A
EP0643996A11995-03-22
US5057338A1991-10-15
US4990368A1991-02-05
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Claims:
WE CLAIM 31
1. A process for incoφorating an additive within a polymer substrate, comprising the steps of: a. electrostatically depositing an effective amount of a powder onto a surface of a polymer substrate, the powder comprising a plurality of dry, heat fusible, particles selected from the group consisting of heat stabilizers, preservatives, antistatic agents, adhesion promoting agents, light stabilizers, flame retardants, antisoiling agents; antistain agents, mixtures thereof and mixtures thereof with dyeing agents; and b. heating the particles to a temperature above the Tg of the substrate and above the melting point of the particles but below the melting point of the substrate for a time sufficient to melt the particles and cause the melt to substantially diffuse into the substrate.
2. The process of claim 1 wherein the polymer is selected from the group consisting of homopolymers, copolymers, blends and grafts of polyamides, polyesters, polyolefins, polyvinyls, fluoropolymers, acrylics, aramids, acetates, and polycarbonates.
3. The process of claim 2 wherein the substrate is a film, a fiber, or an article manufactured from such a fiber.
4. A solventfree process for incoφorating an additive within a polymer substrate, comprising the steps of: a. electrostatically depositing an effective amount of a dyefree powder onto a surface of a polymer substrate, said powder comprising a plurality of dry, heat fusible, additive particles; and b. heating the particles to a temperature above the Tg of the substrate and above the melting point of the particles but below the melting point of the substrate for a time sufficient to melt the particles and cause the melt to substantially diffuse into the substrate.
5. The process of claim 4 wherein the polymer is selected from the group consisting of homopolymers, copolymers, blends and grafts of polyamides, polyesters, polyolefins, polyvinyls, fluoropolymers, acrylics, aramids, acetates, and polycarbonates.
6. A solventfree process for rendering a surface of a polymer substrate stable to light, comprising the steps of: a. electrostatically depositing an effective amount of a powder onto a surface of a polymer substrate, said powder comprising a plurality of dry, heat fusible, light stabilizing particles; and b. heating the particles to a temperature above the Tg of the substrate and above the melting point of the particles but below the melting point of the substrate for a time sufficient to melt the particles and cause the melt to substantially diffuse into the substrate.
7. The process of claim 6 wherein the light stabilizing particles are ultraviolet light absorbing particles.
8. The process of claim 7 wherein the polymer is polyester.
9. The process of claim 8 wherein the ultraviolet light absorber is chosen from the group consisting of hydroxybenzophenones, hydroxybenzotriazoles, cinnamates, cinnamamides, oxanilides, and combinations thereof.
10. The process of claim 6 wherein the powder further comprises a plurality of dry, heat fusible dye particles, to thereby simultaneously dye the surface on which the powder is deposited and render the surface resistant to fading and degradation by light.
11. The continuous process of claim 10 wherein the substrate is a length of woven fabric which is maintained under tension during the depositing and heating steps.
12. The process of claim 11 wherein the polymer is polyester.
13. A process for rendering a surface of a polyester or polyamide substrate adherent to another material, comprising the steps of: a. electrostatically depositing an effective amount of a powder onto a surface of the substrate, said powder comprising a plurality of dry, heat fusible adhesion promoting particles; and b. heating the particles to a temperature above the Tg of the substrate and above the melting point of the particles but below the melting point of the substrate for a time sufficient to melt the particles and cause the melt to substantially diffuse into the substrate.
14. The process of claim 13 wherein the adhesion promoting particles are selected from the group consisting of epoxides, epoxy silanes, isocyanates, polyhydroxyl compounds, and chlorinated organics.
15. The process of claim 14 wherein the substrate is polyester and the other material is rubber.
16. A tire cord made in accordance with the process of claim 15.
17. A woven polymeric fabric comprising a plurality of multifilament waφ yam bundles and at least one multifilament weft yam bundle, said fabric having diffused therein on at least one surface thereof an additive selected from the group consisting of heat stabilizers, preservatives, antisoiling agents, antistatic agents, adhesion promoting agents, light stabilizers, flame retardants, antistain agents, mixtures thereof and mixtures thereof with dyeing agents, said fabric being characterized by a minimum weight ratio of the additive within the multifilament waφ yam bundle to that within the multifilament weft yam bundle of about 1 to 1. 18.
18. The woven fabric of claim 17 wherein the filaments of said multifilament waφ yam bundles are characterized by intermittent regions containing the diffused additive and intermittent regions that are additivefree.
19. A polyester woven fabric according to claim 18 wherein said additive is a UV light absorbing additive.
20. A seat belt made with the fabric of claim 19.
Description:
POLYMER SUBSTRATE WITH ADDITIVES AND THERMALLY INDUCED DIFFUSION PROCESS FOR MAKING

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a polymer substrate with additives diffused therein and to the thermally induced diffusion process for making the same. More particularly, this invention relates to an organic polymer fiber or article manufactured therefrom with an additive or additives diffused therein to stabilize, modify or enhance properties thereof. This invention specifically relates to woven polyester or polyamide fabric which has a light stabilizer diffused therein by a thermally induced diffusion process to render the fabric resistant to fading and degradation by light without substantially impairing physical properties. This invention also specifically relates to polyester fiber and polyester or polyamide fabric which has an adhesion promoter substantially diffused therein by a thermally induced diffusion process to improve adhesion to various coatings.

2, Prior Art It is known to use dyed narrow web fabrics woven from organic polymer fibers such as polyester and polyamide as seat belt material in automobiles and planes. Prolonged exposure to sunlight (weathering) has a tendency to fade the dyed web material and to reduce its physical properties such as strength retention and resistance to elongation. This occurs when the dye and polymer components of the material absorb damaging wavelengths of light. Significant damage is caused by absorption of ultraviolet (UV) light of wavelengths shorter than » 400 nanometers.

Automotive applications require lightfastness for dyed materials, such as seat belts, to minimize color changes and strength loss on exposure to UV light. Many of the dyes currently used in seat belts are not Lightfast, and it is unlikely that significantly more light stable dyes will become available in the foreseeable future. The established polymers presently used to produce fiber for narrow web are also not likely to be replaced by significantly more light stable polymers in the near future since the more light stable polymers have comparatively unacceptable strength properties.

One approach toward reducing the photodegradation of polymers and/or dyes within them is to add a very light stable, strongly absorbing material which will effectively screen the incoming radiation by competing with the dye and polymer components for absorption of the damaging wavelengths of light. If the screen absorbs and effectively converts the damaging wavelengths of light to harmless thermal energy, the dyed polymer substrate will have improved lightfastness and be able to pass more stringent lightfastness requirements.

Light stabilizers, particularly UV light absorbers, are known for use with polymer substrates such as films, fibers and articles manufactured therefrom. The two most common methods of incorporating the light stabilizers are via mixing with the base polymer and by coating, dipping or overspraying the film, fiber or woven fabric. Since damage to dyes as well as the polymer structure itself occurs primarily near the surfaces where Light is absorbed, mixing with the base polymer, where the stabilizer is uniformly distributed throughout the article, is wasteful, inefficient, and expensive. Clearly, in fabric constructions it is of no effect to place a light stabilizer in regions of a filament or yarn bundle that are not exposed to light, e.g., in fill fibers, or the portions of fibers covered at crossover points. Furthermore, many of the commercially available light stabilizers do not have sufficient thermal stability to survive melt incorporation into the polymer or downstream processing, especially with a polyester such as polyethylene terephthalate where processing temperatures may exceed 300°C. Other typical difficulties arising during the melt processing of additives such as UV light absorbers and other light stabilizers in polymers include the degradation of polymer molecular weight, volatilization, extruder screw lubrication and the formation of undesired color. Coating, dipping or overspraying typically requires the stabilizer be applied in solution, dispersion or emulsion form, after the film, fiber or article has been produced. This type of application has the potential advantage of concentrating the stabilizer where it is most effective. However, the solvents and/or other liquids used as carriers for the stabilizer can pose environmental and workplace hazards. Most solvent based application methods also have the drawback that the solvent carrier penetrates the interstitial spaces of fiber yarns,

woven fabrics and polymer structures with surface texture to carry with it the light stabilizer or other additive. The result is that the additive is placed deep within the object where it is ineffective at stabilization or surface property modification. It would therefore be advantageous to have a solvent-free and thus environmentally friendly process to apply UV light stabilizers and/or other property modifiers or additives to polymeric substrates such as molded objects, fiber and fabric, and in particular to seat belt webbing. Such a process should strategically concentrate the stabilizer in the substrate near its surface where it is most beneficial and economical. It would be particularly advantageous to have an application process that utilizes portions of an existing manufacturing process to accomplish one or more of its steps. The present invention achieves all of this. The closest prior art of which applicants are aware is found in U.S. Patents 3,043,709 and 5,213,847, and in an article by J. Ricker et al entitled, "Use of the Electrostatic Powder Spraying Process for Dyeing Polyester," 71 Melliand Textilber. Issue 7, pp. 533-35 (1990). None of these publications, however, teaches the applicants' solvent-free, thermally induced diffusion process for incorporating additives within a polymer substrate.

SUMMARY OF THE INVENTION The present invention is a solvent-free, environmentally friendly, cost- effective process of incorporating additives within a polymer substrate to stabilize and/or modify the same. The process eliminates the use of solvents, levelling agents, pH modifiers, and dispersing aids while making efficient use of the additives, which are placed only at selected surfaces rather than being uniformly distributed throughout the substrate. It also permits the incorporation of a wider range of additives since many of those that are thermally unstable or cause undesirable color or cut molecular weight or are volatilized at the higher polymer processing temperatures are thermally stable at the treating temperatures used in the process of this invention. This process comprises the steps of a. electrostatically depositing an effective amount of a powder onto a surface of a polymer substrate, the powder comprising a plurality of dry, heat fusible particles selected from the group consisting of heat stabilizers,

preservatives, antistatic agents, adhesion promoting agents, light stabilizers, flame retardants, antisoiling agents, antistain agents, mixtures thereof and mixtures thereof with dyeing agents; and b. heating the particles to a temperature above the T g of the substrate and above the melting point of the particles but below the melting point of the substrate for a time sufficient to melt the particles and cause the melt to diffuse into the substrate. This invention also includes a product made in accordance with this process.

In an alternate embodiment, the present invention is a solvent-free process for incoφorating an additive within a polymer substrate, comprising the steps of a. electrostatically depositing an effective amount of a dye-free powder onto a surface of a polymer substrate, the powder comprising a plurality of dry, heat fusible additive particles; and b. heating the particles to a temperature above the T, of the substrate and above the melting point of the particles but below the melting point of the substrate for a time sufficient to melt the particles and cause the melt to substantially diffuse into the substrate. The product made by this process is also part of the present invention.

The present invention is also a solvent-free process for rendering a surface of a polymer substrate stable to light, with the attendant advantages stated previously. The process comprises the steps of: a. electrostatically depositing an effective amount of a powder onto a surface of a polymer substrate, the powder comprising a plurality of dry, heat fusible, light stabilizing particles; and b. heating the particles to a temperature above the T g of the substrate and above the melting point of the particles but below the melting point of the substrate for a time sufficient to melt the particles and cause the melt to diffuse into the substrate. This embodiment preferably is a continuous process wherein the substrate is a length of woven fabric, preferably polyester, which is maintained under tension during the depositing and heating steps. The preferred tension ranges from about 445 to about 6670 N, more preferably from about 1110 to about

5560 N, and most preferably from about 2200 to about 4450 N, The preferred heat treatment is at a temperature of about 200 to about 250°C, more preferably about 210 to about 240° C, for about 1 to about 6 minutes, more preferably about 1.5 to about 3.5 minutes. In the instance where the substrate comprises a fabric with a plurality of unfixed, heat fusible dye particles already on the surface on which the powder is to be deposited, the heating step also serves to set the dye particles on the surface. Alternatively, this embodiment permits the simultaneous solvent-free dyeing of the substrate when the powder further comprises a plurality of dry, heat fusible dye particles. By this alternative process, the use of leveling agents and the exhaustion of dye bath can be avoided. This invention also includes the product made in accordance with this process, which preferably is a seat belt webbing.

The products made in accordance with the above-described processes of the present invention preferably are characterized by having the additive particles diffused therein at a loading of from about 0.01 to about 10 weight percent, more preferably from about 0.1 to about 5.0 weight percent, and most preferably from about 0.1 to about 2.0 weight percent. The additive is distributed in surface regions of the substrate to modify surface properties.

A particularly preferred product of the present invention is a dyed, woven polyester fabric, preferably a narrow web for seat belts, comprising a plurality of multi-filament waφ and multi-filament weft yarn bundles wherein the powder diffused into the woven fabric at the loadings set forth above comprises a plurality of light stabilizer particles, preferably of a hydroxybenzophenone, and most preferably of 2,4-dihydroxybenzophenone, further characterized by a n inimum weight ratio of the stabilizer within the multi-filament waφ to that within the multi- filament weft yam bundles of about 1 to 1, with higher weight ratios being preferred. At light to medium loadings, the stabilizer is diffused at intermittent regions into the filaments of the multi-filament waφ yarn bundle. Those regions that do not contain any stabilizer correspond to cross-over points in the webbing, i.e., where the waφ yarn bundle crosses over the weft yarn bundle. In the most preferred embodiment, the product comprises at least one multi-

filament yarn bundle characterized by asymmetric stabilizer diffusion therein, with respect to a cross-section thereof.

In yet another embodiment, this invention is a solvent-free process for rendering a surface of a polyester or polyamide substrate adherent to another material, such as polyurethane, polyvinyl chloride, or rubber, comprising the steps of: a. electrostatically depositing an effective amount of a powder onto the surface of the polymer substrate, the powder comprising a plurality of dry, heat fusible, adhesion promoting particles; and b. heating the particles to a temperature above the T g of the substrate and above the melting point of the particles but below the melting point of the substrate for a time sufficient to melt the particles and cause the melt to diffuse into the substrate. By virtue of this process, higher molecular weight materials can be used as adhesion promoters without the attendant environmental concerns regarding disposal, recovery or containment of solvent carriers. This invention includes a polyester tire cord made in accordance with this process and having improved adhesion to rubber, as well as the resulting tire. It also includes a woven polyester or polyamide fabric made in accordance with this process and having improved adhesion to a coating of polyurethane, polyvinyl chloride, or rubber, such as neoprene, as well as the resulting coated fabric.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood and further advantages will become apparent when reference is made to the following detailed description of the invention and the accompanying drawings in which: FIGURE 1 is a perspective view of a partial length of a filament taken from a multi-filament waφ yarn bundle having a medium loading of powder diffused therein, showing the intermittent regions of powder diffused therein; and

FIGURES 2A, 2B, 2C and 2D are views in cross-section of multi-filament waφ yarns having, respectively, no powder diffused therein, a high loading of powder diffused therein, a medium loading of powder diffused therein, and a low loading of powder diffused therein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention permits the incoφoration of a wide range of additives at selective surfaces/sites of a polymer substrate to stabilize and/or modify the same. The process essentially comprises the steps of: (a) electrostatically depositing an effective amount of a powder onto a surface of a polymer substrate, the powder comprising a plurality of dry, heat fusible, additive particles; and (b) heating the particles to a temperature above the T ( of the substrate and above the melting point of the particles but below the melting point of the substrate for a time sufficient to melt the particles and cause the melt to substantially diffuse into the substrate.

The invention will be described for polymer fibers and articles manufactured from such fibers, e.g., mono- or multi-filament fiber, cordage, broad and narrow fabrics (woven, nonwoven, and knitted). However, the polymer substrate can additionally include film, molded objects, and the like, so long as the chosen substrate is capable of having the additive particles substantially diffused thereinto according to the processes to be described. Preferred polychlorotrifluoroethylene films include homopolymers and copolymers of chlorotrifluoroethylene. The more preferred polychlorotrifluoroethylene films are commercially available from AlliedSignal Inc., Morristown, New Jersey as ACLARΘfilm or HALAR®film as indicated in the following Table I:

TABLE I ALLIEDSIGNAL INC. PRODUCTS

FTLM POLYMER

ACL AR® RX 160 Homopolymer of Chlorotrifluoroethylene ACLAR® 22A Copolymer of Chlorotrifluoroethylene and 3-4 weight percent Vinylidene Fluoride

ACLAR® 88 A Copolymer of Chlorotrifluoroethylene and 3-4 weight percent Vinylidene Fluoride

ACLAR® 33 C Teφolymer of Chlorotrifluoroethylene, < 1 weight percent Vinylidene Fluoride, and < 1 weight percent

Tetrafluoroethylene

HALAR® Copolymer of 60 weight percent Ethylene and 40 weight

Chlorotrifluoroethylene

8

The preferred substrates are fabrics, particularly narrow woven fabrics, and cordage.

While the processes of this invention will be described herein primarily in terms of seat belt webbing and tire cordage made from polyester yarns of, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and copolymers and polymer blends thereof, it is clear that the processes can be used to incoφorate additive particles in a wide variety of other polymer substrates, either organic or inorganic. A detailed Listing of various organic and inorganic polymers for fibers and articles made therefrom is found in U.S. Patent 5,376,426 and European Patent 0389427 A2, both of which are hereby incoφorated by reference. Organic polymer substrates are preferred, such as substrates composed of homopolymers, copolymers, blends, and grafts of the following materials: polyamides; polyesters; polyolefins; polyvinyls; fluoropolymers; acrylics; aramids; acetates; and polycarbonates. Inorganic polymer substrates composed of, e.g., polyphosphazenes, polythiazyls, may also be used, although they are less preferred. The substrates may be formed from a combination of different polymers, e.g., fabrics may be formed which utilize different fiber types in a hybrid construction (a fabric blend) taking advantage of the different fiber properties, or a substrate may be formed from fabric layers of different fiber types. These are all deemed to be encompassed by the present invention. The preferred substrates are formed with organic polymers, although blends of organic and inorganic polymeric substrates, e.g., fabric blends of organic and inorganic fibers, are considered to be part of the present invention.

The term polyamide as used herein denotes those synthetic long chain polyamides having recurring amide groups as an integral part of the polymer chain. Exemplary of such polyamides are nylon 6; nylon 6,6; nylon 4,6; nylon 7; nylon 10. nylon 11; nylon 12; etc. The preferred polyamide substrates are the broad woven coated fabrics wherein the coatings can be polyurethanes, polyvinyl chlorides, and various rubbers, such as neoprene. The additive particles are chosen to enhance adhesion of the polyamide substrate to the coating and/or to enhance the UV light stability of the polyamide substrate.

The term polyester as used herein denotes homopolymers, copolymers and polymer blends of polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). The PEN polymer preferably contains at least about 85 mol percent polyethylene naphthalate. This polyester may incoφorate as copolymer units minor amounts of units derived from one or more ester-forming ingredients other than ethylene glycol and 2,6-naphthalene dicarboxylic acid or their derivatives. Illustrative examples of other ester forming ingredients which may be copolymerized with the polyethylene naphthalate units include glycols such as 1,3- propanediol, 1,4-butanediol, 1,6-hexanediol, etc., and dicarboxylic acids such as terephthalic acid, isophthalic acid, hexahydroterephthalic acid, stilbene dicarboxylic acid, bibenzoic acid, adipic acid, sebacic acid, azelaic acid, etc. See U.S. Patent 5,397,527, hereby incoφorated by reference to the extent not inconsistent herewith. The PET polymer preferably contains at least about 85 mol percent polyethylene terephthalate. This polyester may incoφorate as copolymer units minor amounts of units derived from one or more ester-forming ingredients other than ethylene glycol and terephthalic acid or its derivatives. Illustrative examples of other ester-forming ingredients which may be copolymerized with the polyethylene terephthalate units include glycols such as diethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, etc., and dicarboxylic acids such as isophthalic acid, hexahydroterephthalic acid, bibenzoic acid, adipic acid, sebacic acid, azelaic acid, etc. See U.S. Patent 5,234,764, hereby incoφorated by reference to the extent not inconsistent herewith. PET/PEN polymer blends with up to about 35 weight percent of PEN and about 65 to 100 weight percent PET, as PET and PEN are defined above, can be used. Conversely, PEN PET polymer blends with up to about 35 weight percent of PET and about 65 to 100 weight percent PEN, as PET and PEN are defined above, can also be used. The preferred polyester substrates are broad woven fabrics, especially air bags and awnings, where the additive particles are chosen to enhance light stability and adhesion to rubber; narrow woven fabrics, especially automotive seat belt webbing, where the additive particles are chosen to enhance light stability; and tire cordage

where the additive particles are chosen to enhance adhesion of the fiber to a coating which in turn adheres the fiber to rubber.

The term polyolefin as used herein denotes polymers containing at least about 85 percent by weight of ethylene, propylene, or other olefin units. The preferred polyolefins are polyethylene, polypropylene and polytetrafluoroethylene. The preferred polyethylene substrate is a SPECTRAΦSHIELD composite or a woven fabric where the additive particles are chosen to enhance light stability and/or flame retardance. The preferred polypropylene substrates are fibers, ropes and films where the additive particles are chosen to enhance light stability. The term polyvinyls as used herein denotes polymers containing a number of vinyl, CH 2 :CHX, groups units in a polymerized form. Polyvinyl derivatives include polyacrylonitrile, polyacrylate, polyvinyl chloride, and polystyrene. The preferred substrates are fibers or fabrics where the additive particles are chosen to enhance flame retardance or light stability. The preferred polycarbonate substrates are molded objects, such as visors, headlamps, and tail light covers, where the additive particles are chosen to enhance light stability.

Table II below sets forth a preferred list of fibers useful in forming some of the polymer substrates of this invention. These fibers are commercially available from AlliedSignal Inc., and are described in greater detail in the AlliedSignal Fibers Industrial Fibers Guide (1994), hereby incoφorated by reference.

TABLE H ALLIEDSIGNAL INC. PRODUCTS FIBER (POLYMERS PRODUCT DESIGNATION nylon 6 1D70, 1G81, 1R70, 1R79, 1R86, 1R88 polyethylene 1W70, 1W72, 1W86, 1X30, 1X40, 1X50, 1X90 terephthalate polyethylene SPECTRA®900, SPECTRA®1000

By melting point of the polymer in the substrate is meant the temperature at which the first principal endotherm is seen which is attributable to the major polymer constituent in the substrate. By melting point of the particles is meant the temperature at which the solid and liquid states of the additive material coexist in equilibrium. The glass transition temperature, T g , of the polymer substrate is the approximate midpoint of the temperature range over which the glass transition takes place, and is measured using a differential scanning calorimeter (DSC) (See ASTM D883 and E1356-91, and Peyser, "Glass Transition Temperatures of Polymers," Polymer Handbook. 3d Ed., John Wiley & Sons, Inc., pVI-209 et seq. (1989). Melting points of various polymers can be found in the Polymer Handbook and are typically available from the particular manufacturer of the polymer or polymer substrate. By way of example, for PET fibers from Table π, the T g ranges from about 60 to about 85°C, and the melting point ranges from about 240 to about 255°C. For nylon 6 fibers from Table π, T, ranges from about room temperature to about 60°C, depending on the humidity and the melting point ranges from about 210 to about 225°C. (measured @ 20°CJmin. heating rate by DSC).

Descriptions of the electrostatic deposition of powders onto workpieces can be found in U.S. Patents 4,808,432, 5,073,579 and 5,213,847, all of which are hereby incoφorated by reference. Essentially, the workpiece, or in this instance the substrate, is exposed to a cloud of electrostatically charged particles with the substrate at an electrical potential effective to attract the particles of the cloud thereto to form a coating. The substrate can be exposed by passing it over or through a fluidized bed of the particles, or the particles can be projected toward the substrate by using a spray gun especially adapted for that puφose. The preferred application is via an electrostatic fluidized bed process with the substrate at ground potential. A single surface or all surfaces of the substrate can be powder coated in this manner, as preferred.

The particles must be dry, i.e., amenable to electrostatic spray deposition without the use of solvents or other liquid carriers. This is not meant to preclude an absence of all moisture since tacky substances are contemplated for use, so long

as they can be fluidized. Powder is defined in accordance with the British Standards Institution, Chemical Dictionary. 5th ed. (1958), as discrete particles of dry material, the maximum dimension of which is less than 1,000 μ. Average particle size in the powder preferably is less than about 250 μ, more preferably less than about lOOμ.

It is required that the additive particles be heat fusible, which means that they are capable of being reduced to a liquid or molten state by sufficient heat. The melting point of the particles must be below that of the polymer(s) in the substrate so that the particles can be substantially diffused into a surface of the substrate without degradation of the substrate. The molecular weight of the additive(s) is such that the particles can be substantially diffused into a surface of the substrate; a range of up to about 3000 is acceptable, more preferably about 200 to about 1000, and most preferably about 200 to about 800. By substantially diffused is meant the molecular migration of the molten particles into the polymer substrate. This is in contrast to fusion of the particles to form a continuous boundary layer on the surface of the substrate wherein the fused boundary layer is contiguous to and adheres to but does not penetrate the surface of the substrate. The diffusion is thermally induced by the heating step.

The heating step preferably takes advantage of an existing heating step during the manufacture of the polymer substrate. For example, the heat of the thermosol fabric dyeing process is preferably utilized to heat treat polyester seat belt webbing onto which additives have been deposited in accordance with this invention; a hot air oven or steam cans are typical thermosol heating devices (see detailed description of process in U.S. Patent 4,376,802, hereby incoφorated by reference). In this instance, the heating step is part of an existing continuous process - the continuous length of seat belt webbing is maintained under tension in the treating zone to avoid curling or shrinkage and to permit diffusion of the additives thereinto. Preferred tension on the webbing is from about 445 to about 6670 N, more preferably from about 1110 to about 5560 N, and most preferably from about 2200 to about 4450 N. Note, however, that the entire process can occur between thermosol dyeing and overcoating, as an independent step or as a

separate process. Also for illustration, the heat of a drawing step can be utilized to heat treat undrawn polyester fiber onto which adhesion promoting additives have been deposited in accordance with this invention; heated rolls or a draw point localizing jet are typical drawing devices. Heating may, however, be by any appropriate means, and convection (hot air), conduction (contact), irradiation (infrared), induction heating, and the like, are all contemplated as within the scope of the present invention.

The heating temperatures and duration of treatment are dependent to a large degree on the particular polymer substrate. For example, with polyester woven fabric, heating temperatures of about 200 to about 250°C, more preferably about 210 to 240°C, for a time period of about 1 to about 6, more preferably about 1.5 to 3.5, minutes, is effective to melt the additive particles and cause the melt to substantially diffuse into the fabric. These correspond to the thermosol process heating conditions for polyester seat belt webbing. Clearly, lower temperatures correspond to longer treatment times while higher temperatures correspond to shorter treatment times. These temperatures would be too high, however, for heat treating a polyethylene or polypropylene surface, due to their lower melting points. Appropriate adjustment of heat treatment temperatures and durations to accommodate the different substrates should be made.

Likewise, the additives to be applied as well as the loading will depend on the particular polymer substrate. The products of the present invention preferably are characterized by having the additive particles diffused therein at a loading of from about 0.01 to about 10 weight percent, more preferably from about 0.1 to about 5 0 weight percent, and most preferably from about 0.1 to about 2.0 weight percent. Because the additive can be distributed in selected surface regions of the substrate to modify surface properties, lower weight percentages are possible.

There are basically two types of additives: stabilizing additives and end-use modifying additives. Stabilizers increase the lifespan of resin and plastic substrates by preventing their degradation by environmental factors. End-use modifying

additives are self defining - they modify the substrate according to the end use. Both types of additives are encompassed by this invention. Stabilizing additives contemplated for use in this invention include heat stabilizers, preservatives, and light stabilizers. End-use modifying additives contemplated for use in this invention include antistatic agents; antisoiling agents; antistain agents; colorants; adhesion promoters; and flame retardants.

Useful heat stabilizers include the mixed metal stabilizers; organotin and mercaptotin compounds; lead salts; and antimony mercaptides. Preservatives, which prevent biological degradation of plastics by microorganisms, can include bactericides; bacteriostats; fungicides; and fungistats.

Light stabilizers are used in a variety of polymers which are either highly susceptible to degradation by light or are frequently used in outdoor service, e.g., polyolefins, polycarbonates, polystyrenes, polyesters, polyamides, and polyvinyl chlorides. The most typical light stabilizers include antioxidants, UV light absorbers, radical scavengers, nickel organics, benzoates, salicylates, and acrylates. Useful antioxidants include the phenolics, e.g., simple phenols, bisphenols, thiobisphenols and polyphenols; aromatic amines, e.g., largely p-phenylenediamines and diphenylamines; thioesters, e.g., reaction products of fatty alcohols and an organic sulfide, typically thiodipropionates; phosphorous based antioxidants, e.g., phosphites; and others, such as the hydroquinones. The UV light absorbers include hydroxybenzophenones (also sulfonated); benzotriazoles (also sulfonated); cinnamates; cinnamamides; oxanilides; and combinations thereof. Useful radical scavengers include hindered amine light stabilizers; and singlet oxygen scavengers such as 1,3-diphenylisobenzofuran and carotenoids. Examples of organic nickel complexes include nickel dialkyldithiophosphates; nickel xanthates; nickel dibutyldithiocarbamates; nickel schiff base chelates; nickel oxime chelates; nickel hydrazone chelates; nickel salicylates; and nickel pyrazole chelates. A useful benzoate includes resorcinol monobenzoate. See Rabek, J., Photostabilization of Polymers Principles and Applications. Elsevier Applied Science, New York, 1990, hereby incoφorated by reference. The most preferred light stabilizers are the UV

light absorbers, especially the hydroxybenzophenones and benzotriazoles; excellent results have been obtained with 2,4-dihydroxy-benzophenone (UVINUL®3000, BASF Coφ.); 2,2'-dihydroxy-4,4'-dimethoxybenzophenone (UVTNUL®3049, BASF Coφ.); and TINUVTN 326 PST, a benzotriazole (CAS 107-21-1, CIBA- Geigy Coφ.).

Antistatic additives function to reduce the accumulation or increase the rate of dissipation of electrical charge on the surface of polymers. Useful antistatic agents include the amines;tensides; quaternary ammonium compounds; anionic surface active agents, e.g., sulfonates phosphates; and others such as glycol esters, sulfated waxes, fatty amides, and polyhydric alcohol derivatives.

Antisoiling agents useful in the processes of this invention include fluorocarbonylimino biurets; fluoroesters; and fluoroester carbamates. See U.S. Patent 5, 153,046, hereby incoφorated by reference. Antistain agents useful in the processes of this invention include sulfonated aromatic condensates and polymers and copolymers of maleic anhydride. Naturally, these additives must be of sufficiently low molecular weight that diffusion occurs at a reasonable rate.

Colorants useful in this invention include the organic pigments, e.g., phthalocyanine blues, phthalocyanine greens, organic reds, organic yellows; disperse dyes, e.g., azo dyes, bis-azo dyes, nigrosines, anthraquinones, xanthenes, sulfonamide dyes, nitro-aromatic dyes; optical brighteners; fluorescents; phosphorescents; and pearlescents. When disperse dyes are used as additives in the present invention, they are coupled in a powder with other additives.

Adhesion promoting additives that can be used in the processes of this invention include epoxides, like Epon 1001 F available from Shell; epoxy silanes; isocyanates, like caprolactam blocked isophorouediisocyanate available from Huls AG; polyhydroxyl compounds; and chlorinated organics. For fiber applications, these adhesion promoters can be applied at any part of the fiber production process; typically, application would occur just prior to drawing or winding. The adhesion promoters could also be applied after fiber production in processes in the fiber plant such as waφing, be-uning, and rewinding, or further downstream in the process like twisting or weaving. The key is that application of the adhesion

promoter must occur prior to application of the coating to which the fiber is to adhere. The coating is applied to the fiber for adhesion to a secondary substrate. By way of illustration, an epoxide would be applied to a polyester fiber to improve adhesion of the fiber to a resorcinol-formaldehyde-latex (RFL) coating, which in tum would adhere the fiber to rubber (secondary substrate) which subsequently undergoes vulcanization. For broad woven fabrics of polyamide or polyester, the adhesion promoter is applied, preferably subsequent to weaving, to improve adhesion of the fabric to protective coatings such as polyvinyl chloride, polyurethane, or rubber, which enhance end-use performance of the fabric. Flame retardants are used to reduce the combustibility of plastics. Useful retardants include the inorganics; nonreactive organics, e.g., bromine compounds, chlorinated paraffins and cycloaliphatics, and phosphate esters; and reactive organics such as epoxy intermediates, polycarbonate intermediates, polyester intermediates, and urethane intermediates. Several additives may be incoφorated within the polymer substrate via a single powder so long as the particles of the powder can be fluidized and the melting points of the various additives are compatible, i.e., not so disparate that at the higher temperatures required to melt the higher melting additive particles the lower melting additive particles degrade, volatilize or otherwise become unsuitable for use. Preferred powder mixtures include light stabilizers with antisoiling agents, antistain agents, slip or grip modifiers, and colorants for seat belt webbing.

Products made in accordance with the processes of the present invention have a multitude of uses. Applications where weathering or exposure to sunlight are a major concern include, by way of example, outdoor clothing, interior automotive fabrics, marine fabrics, marine slings, marine ropes, cordage, agricultural fabrics, awnings, canopies, tents, flags, banners, outdoor furniture, sports equipment, personal flotation devices, sails, parachutes, soft-sided luggage, geotextiles, animal control webbings, cargo tie-downs, industrial lifting slings, military webbings, parachute harnesses, seat belt webbing, and automotive molded parts such as headlamps and tail light covers. Other applications where adhesion is

a major concern include coated fabrics (e.g., soft truck panels) and industrial fabrics, as well as reinforcement for tires, conveyor belts, hoses, and V-belts.

The preferred process of the present invention is a solvent-free, continuous process for rendering a polyester surface of a length of seat belt webbing resistant to fading and degradation. Additives are placed asymmetrically on upper yam bundles and not uniformly dispersed throughout the seat belt webbing. The seat belt webbing construction is a woven 2/2 twill, knitted lock stitch, nominally about 2.0 inches (about 5 cm) in width with a thickness of about 0.047 inch (about 0.12 cm). Approximately eight webbings are fed in parallel at a speed of up to about 20 yds/min (about 18 m/min) through a treating zone under tension of from about 445 to about 6670 N, more preferably from about 1110 to about 556 N, most preferably from about 2200 to about 4450 N. Maintaining the webbings under tension prevents curling or shrinkage. Tension is preferably provided by running the take-up rollers at the exit end of the treatment zone at a slightly faster speed than the feed rollers to the treatment zone. The feed webbing preferably is pre- dried and dyestuff-coated (unfixed) as described in more detail in Example 1 below. An effective amount of a powder containing a plurality of dry, heat fusible, UV light absorbing particles is deposited on all exterior surfaces of the webbing via a vertical fluidized bed electrostatic powder coater. The preferred UV light absorber is a hydroxybenzophenone or a benzotriazole, more preferably the former. The powder add-on weight is at a loading of from about 0.01 to about 10 weight percent, more preferably from about 0.1 to about 5.0 weight percent, and most preferably from 0.1 to about 2.0 weight percent. The objective, clearly, is to add the minimum amount of UV light absorber necessary to render the seat belt webbing resistant to fading and degradation by light. The dyestuff-coated and additive-coated webbings are then heat treated by exposure to a temperature of about 200 to about 250°C, more preferably about 210 to about 240°C, for about 1 to about 6, more preferably about 1.5 to about 3.5, minutes in the treating zone. The time and temperature are sufficient to melt the powder particles and cause the resulting melt to diffuse into the webbings. Simultaneously, the dyes are heat set. The webbings may then be neutralized, washed with detergent, rinsed, dried, and

taken up. The webbings can then be overcoated with an aqueous dispersion (e.g., ODM- 1 and ODM-FT, commercially available from Dooley Chemical) followed by drying and take-up, all as is well known in the art.

The product of this process is a dyed, woven polyester seat belt webbing comprising a plurality of multi-filament waφ and multi-filament weft yam bundles. The weight ratio of the UV light absorber within a multi-filament waφ yam bundle to that within a multi-filament weft yam bundle ranges from a minimum of about 1 to 1 and up, with higher ratios being preferred. The typical weight ratio ranges from about 1.5 to about 3.5 to 1. At low to intermediate loadings of the additive, the UV light absorber is diffused at intermittent regions along the length of the waφ filaments. Those regions without any diffusion of absorber correspond to crossover points in the webbing, i.e., where the waφ yam bundle crosses under the weft ya bundle. Thus, the UV light absorber can be selectively placed primarily on the surface filaments of the peak fiber bundles where weathering occurs, and thus avoid the waste of uniform concentration of UV light absorber throughout all multi-filament ya bundles. The maximum migration of the UV light absorber into the seat belt webbing is about 40 μ.

In the accompanying examples, seat belt webbing construction was as follows. A 2/2 twill, knitted lock stitch, seat belt webbing was woven utilizing a commercially available Mueller needle loom, Model ND, to be nominally 2.0 inches in width with a thickness of 0.047 inch. The webbing construction consisted of 342 warp ends of 1300 denier, 100 filaments, zero twist polyester yam with a filling ya (weft end) consisting of 16.7 double insertion picks per inch of 840 denier, 70 filaments, zero twist polyester yam. The knitted lock stitch consisted of 500 denier, 70 filaments, zero twist polyester yam. Unless indicated otherwise in the examples, the yams used were polyethylene terephthalate yams commercially available from AlliedSignal, Inc., as, respectively, 1300-100-00- 1W70; 840-70-00- 1W70; and 500-70-00-1W70.

In the accompanying examples, the aqueous dye baths all contained 4.0 g L Hostapur DAD, a nonionic alkyl alcohol polyglycol ether wetting agent, commercially available from Hoechst-Celanese Coφoration; 10.0 g/L Hyonic OP-

5 , a nonionic dispersing agent, commercially available from and proprietary to Henkel Process Chemicals, Inc.; dyes (as detailed in Table III, hereafter); and acetic acid to maintain pH of the bath at 4.8 - 5.0.

Certain processes and tests utilized in illustrating the invention are defined below. All seat belt webbings met the requirements of Federal Motor Vehicle

Safety Standard No. 209 (FMVSS 209) in addition to General Motors Engineering Standards Specification GM2704M (see tests and standards set forth therein), all of which are hereby incoφorated by reference. SAE J1885 (87) specifies the operating procedures for a controlled irradiance, water cooled xenon arc apparatus used for the accelerated exposure of various automotive interior trim components. Under 2.1, This test method is designed to simulate extreme environmental conditions encountered inside a vehicle due to sunlight, heat and humidity for the puφose of predicting the performance of automotive interior trim materials. The xenon arc exposure is widely used in conjunction with Gray Scale or delta E readings to quantify changes in color (fade). Note that for Gray Scale, higher numbers are indicative of better dye lightfastness, while with delta E readings, lower numbers are indicative of better dye lightfastness. The thermosol process for dyeing fabric or seat belt webbing made with polyester yam is set forth in U.S. Patent 4,376,802, hereby incoφorated by reference. EXAMPLE 1

PET seat belt webbing was woven as previously described. The standard disperse dye solutions described above and in Table m were padded on the greige PET seat belt webbing. The dye was applied from a dye bath via a single dip/single squeeze process and the webbing was then passed through an air convection predrier at a temperature of 60°C. with a nominal residence time of two minutes on a lab scale Benz thermosol range. The predried, dyestuff-coated webbing was then powder coated with a UV light absorber, 2,4-dihydroxybenzophenone (UVINUL 3000, commercially available from BASF; mean particle size: volume - 28.3 microns; number - 4.68 microns with a particle geometric diameter range from ca. 2 - 80 microns) containing 0.2 wt% fumed silica as a fluidizing aid on a vertical fluidized bed electrostatic powder coater (Model 602, Electrostatic Technology,

Inc., Branford, CT). The powder add-on wt% was estimated at this stage by sampling and weighing the webbing and comparing to uncoated pieces of webbing of the same length. The weight of the additive deposited on the webbing was estimated to vary from 0 to over 2.5 wt% (based on fiber weight) by a variation in the voltage setting of the electrostatic coater. Typical voltage ranges utilized were 30 to 62kV with resulting estimated add-on percentages between 1.0 and 2.5wt%. Powder coating was carried out at speeds up to 20 yds/min. The samples prepared in Table IV were run at 8 yds/min. The dyestuff-coated (unfixed) and additive- coated web was then passed through a rubber pinch braking roller and into an electric air convection thermosol oven heated at 215°C. at a speed of 1 ydJmin. to complete the dyeing of the webbing and to diffuse the UV light absorber additive into the polyethylene terephthalate filaments of the webbing. The webbing residence time in the thermosol oven was between 1.5 - 2.0 min. with the webbing under a net stretch of about 0.5 to 1.5%. The dyed web with the additive diffused therein was then neutralized in a clearing bath of 2 g/L sodium hydrosulfite at 27°C, washed with detergent in two separate baths at 96-100°C, rinsed with hot water at 96-100°C, and then rinsed in a cold solution of 5 g/L acetic acid (pH 4.5- 5.0). The webbing was then dried by passing over two steam cans and was taken up for testing of dye lightfastness, breaking strength retention (BSR), wet and dry crocking, and water spotting. Control samples were prepared in the same manner but without the addition of any of the UV absorber.

With reference to Table IV, Samples 8 and 14 utilized a voltage setting of 30 kV (estimated 1.0% loading), while Samples 2, 4, 6 and 10 utilized a voltage setting of 35 kV (estimated 1.5% loading), and Samples 12 utilized a voltage setting of 40 kV (estimated 1.9-2.0% loading). Loadings, as measured by extraction and gas chromatography analysis, are set forth in the column headed UV3000 wt%. The scarlet samples (5 and 6) represent the average of two samples. Samples 1 through 6 passed water spotting test; the other samples were not tested. All of the samples passed the wet and dry crocking test. Breaking strength retention (SAE J1885, 225 kJ/m 2 ) showed improvement for Samples 2, 4 and 6, and a slight downturn (from 75 to 73%) for Sample 12; comparative data

was not measured for the other samples. Note the improvement both for Gray Scale (GS) and delta E values at 225kJ/m 2 and 450kJ/m 2 . Measurements were not taken for Samples 7 - 14 for the 450kJ/m 2 .

EXAMPLE 2 In this Example, PET seat belt webbings were woven and fully dyed in accordance with the procedure set forth in Example 1 (pad dyeing without electrostatic deposition of additives). In Table V, the odd numbered samples represent the controls for this Example. The fully dyed webbings of the even numbered samples were electrostatically coated with UVINUL 3000 UV light absorber and heat treated in accordance with the procedure of Example 1 (post treatment). With reference to Table V, Samples 2 and 4 utilized a voltage setting of 65 kV (1.0% loading), while Samples 6 and 8 utilized a voltage setting of 50 kV (0.5% loading). UV testing for fade resistance was then carried out. Note the improvement for both Gray Scale and delta E values at 225 kJ/m 2 . EXAMPLE 3

Commercial greige (undyed) polyethylene terephthalate seat belt webbing of the same construction as that used for the webbings of Example 1 was powder coated with UVINUL 3000 powder using an ETI Model 602 fluidized-bed, powder-coating apparatus. Fumed silica (0.2wt%) was added to the powder to aid in fluidization. The greige webbing was coated at a speed of 8 yds/min with individual high voltage settings of 36k V, 50kV and 64kV on the high voltage grid of the fluidized bed to create three separate webbing samples having low, medium and high loadings of the powdered additive. The three powder coated samples were then thermosoled according to the method described for the dyed webbing of Example 1 including all wash steps.

The concentration of UVINUL 3000 in each sample of greige webbing was determined by extraction and GC analysis. Two 70 - 75 mg samples were cut from each of the greige webbing samples (low, medium, high concentrations), one from the right hand side and one from the left hand side. Each sample was extracted with 2mL of chloroform at ca. 60°C. for 16 h. Gas chromatographic analysis on a 15m OV17 megabore column (1 micron film) using a 20°C/min. temperature ramp

starting at 240°C. with a 5 min. hold at the final temperature of 260°C. followed by comparison of the integrated peak intensities with a standard UW-JUL 3000 calibration curve allowed for the determination of the additive add-on wt%. The wt% loadings are summarized in Table VI. A repeat extraction of a sample that had been through one extraction cycle yielded less than 10% additional UVINUL 3000, thus showing that greater than 90% of the UVINUL 3000 is removed in a single extraction.

The data of Table VI show that increasing the voltage on the high voltage grid of the fluidized bed increases the loadings of powder, with the average concentration of UV absorber in the samples increasing from 0.28 wt% at 36 kV to 0.60 wt% at 50 kV, and finally to 1.28 wt% at 64 kV (average of left and right hand readings).

The spatial asymmetry of the UVINUL 3000 distribution in the webbing was demonstrated via extraction-GC analysis of the waφ and weft fibers separately (Table VI under sample location). The high concentration greige webbing was disassembled and a series of waφ yams were selected for extraction analysis. Similarly samples of weft yams were selected for a separate extraction analysis. The concentration of UVINUL 3000 in the waφ fiber was found to be 2.17 times that in the weft (fill) fiber. The medium, low, and control (zero) concentration greige webbings were also disassembled for extraction analysis of their respective waφ and weft yams. The concentration ratio for the medium concentration webbing waφ fiber was 2.90 times that in the weft fiber, and the concentration ratio for the low concentration webbing waφ fiber was 2.83 times that in the weft fiber. Each greige webbing sample was then examined via UV microscopy. An

Olympus BH-2 microscope fitted with a Photometries Star I UV intensified CCD camera and UVFL 10X, 20X and 40X objectives was used to examine individual filaments pulled from the greige webbing samples. The samples were viewed in transmission with light filtered via a 355nm band pass filter combined with a 357nm interference filter. The resulting ca. lOnm FWHM bandwidth of light was selected

to coincide with the absoφtion of UVINUL 3000 but to be beyond the cutoff edge of the PET webbing.

Three types of samples were prepared for examination of the spatial distribution of UVINUL 3000 in the filaments. First, in order to qualitatively establish the presence of the absorber within the individual filaments, filaments from either waφ or weft yam bundles were selected, mounted longitudinally on a quartz microscope slide and viewed without sectioning (transverse observation = observation transverse to the filament longitudinal direction). Control filaments were mounted in proximity to the UVINUL 3000-treated samples so that both filaments could be viewed simultaneously at 100X magnification. Second, in order to evaluate the spatial distribution of the additive within the filaments, cross sections of the filaments were prepared via standard potting and πύcrotoming techniques. In general, samples of waφ filaments for cross-sectioning were prepared to contain a small number of filaments from several waφ yams. Weft filament samples were prepared by potting single weft yam bundles. Each set of filaments was potted in PMMA and four, 10 micron sections were microtomed from each and mounted on quartz slides. Control filaments of each type were prepared simultaneously and also mounted on quartz slides. Third, waφ or weft yam bundles were placed between dark absorbing yams and compressed in a metal holder which allowed thick sections to be cut. These latter samples were then placed directly on the Olympus microscope stage for viewing at 100X, 200X and 400X. The observations of the spatial distributions for the high and medium loading greige webbing samples are summarized below. The presence of the UVINUL 3000 was indicated by absoφtion of the 357nm light used for the microscopy.

High loading greige webbing: Transverse views of both waφ and weft filaments mounted longitudinally on quartz slides were very strongly absorbing as compared to control filaments which were not treated with UVINUL 3000. In the longitudinal direction, the absoφtion in the waφ and weft filaments seemed to be uniform. There were no distinct pattems of intensity variations along either the waφ or weft fibers that could be associated with variations in UVINUL 3000

concentration due to weaving pattems (e.g. yam or filament crossover points). The distribution of the UVINUL 3000 appeared to be quite uniform for either waφ or weft filaments, and all filaments examined contained UVINUL 3000. Weft filament cross sections were lighter than similar thickness cross sections of waφ filaments, consistent with the lower loading of UVINUL 3000 observed in the extraction data reported in Table VI. Some individual filaments were observed to be as strongly absorbing as the average waφ filament. The distribution of the UVINUL 3000 within the individual waφ filaments was observed to be uniform across any given filament as measured by a line scan taken through the gray-scale imaged cross section data. Thick cross sections (>200 microns) of both waφ and weft yam bundles showed an apparent uniform distribution of the UVINUL 3000 from filament to filament within each yam bundle and across any given filament. See Figure 2B.

Medium loading greige webbing: Transverse views of waφ filaments indicated the presence of UVTNUL 3000 as an increased absoφtion compared with control filaments (no application). However, the absorbance, as indicated by the gray scale values of the digitized image, was significantly less than in the high loading sample. A definite pattern of intensity variations along the filaments was also observed. The lighter regions are dominant, with some being of equivalent intensity to that of the control samples. See Figure 1. Those regions that do not contain any UVINUL 3000 correspond to crossover points in the webbing, i.e., where the waφ yam bundle crosses over the weft yam bundle. In cross section, most of the waφ filaments were found to be absorbing with uniform intensity across an individual filament. In thick sections of waφ yams, a small number of filaments were found to be less strongly absorbing (only slightly more absorbing than control sample waφ filaments). Thus, within waφ yam bundles the UVINUL 3000 can be uniformly distributed across a given filament, yet be asymmetrically placed with respect to the filaments within the yam. See Figures 2C and 2D. The weft filaments, when viewed in thin cross section, appear generally to not contain any UVINUL 3000 (no absoφtion greater than control filaments as indicated by

gray scale values of line scans through the digitized image). A few weft filaments have intermittent dark absorbing sections.

EXAMPLE 4 PET seat belt webbing was woven as previously described. Two powders were formed. The first powder comprised lwt% fumed silica and Scarlet dye powder (see Table III for components). The second powder comprised 75 wt% Scarlet dye powder (see Table m for components), 24wt% UVINUL 3000 UV light absorber, and lwt% fumed silica.

The cavity of a fluidized bed electrostatic coater was filled with the first powder and the voltage set at 75-100 kV. The powder fluidized well. Several one foot lengths of grounded webbing were hand-passed through the powder cloud above the fluidized bed to powder coat the webbings. These powder coated lengths of webbing were then processed as in Example 1 subsequent to powder coating. This procedure was repeated for a second set of webbings and utilizing the second powder.

Both powders deposited easily onto the surface of the webbings despite a slight color discontinuity due to inadequate mixing of the powder prior to application. The samples also dyed well. The samples passed the dry crocking test. It is anticipated that the webbing coated with the second powder will have significantly better dye lightfastness when compared to the webbing coated with the first powder.

This example demonstrates the ability to simultaneously incoφorate additives having different functions within a polymer substrate via a single powder. EXAMPLE 5

Seat belt webbing is woven as previously described for PET yams except that the yams used are PET/PEN yams. The PET/PEN yams are a polymer mixture (90 PET: 10 PEN wt%) whereby the PET and PEN are chip blended and melt-spun into fiber in accordance with the teachings of U.K. Patent 1,343,628, hereby incoφorated by reference. The seat belt webbing is treated as in Example 1. Similar results/data are anticipated.

EXAMPLE 6 An industrial webbing is woven utilizing a needle loom and the following PET yarns, commercially available from AlliedSignal, Inc.: waφ ends of 1300 denier/100 filament zero twist yarn 1300-100-00-1W70; weft yams of 840 denier/70 filament zero twist yam 840-70-00- 1W70; binder yam and lock stitch ya 500 denier/70 filament zero twist 500-70-00- 1W70; filling/stuffer yams 1000 denier/ 192 filament zero twist 1000-192-00- 1W70. The webbing is woven using 342 waφ ends, 16.7 weft ends/inch, and a lock stitch to finish the edge. The webbing is a tubular construction whereby the webbing is woven with two distinct sets of waφ yams (171 ends each) and a common filling yam. The filling yam intersects with each set of waφ selvages to make the tube. As the webbing is being woven, 150 "stuffer" ya s are embedded between the webbing face and back (in effect, to stuff the tube). Approximately 10 evenly spaced binder yams are sewn down the length of the webbing to bind the webbing sandwich. The final webbing is approximately 2 inches in width and 0.060 inch in thickness. The woven webbing is then pigment dyed (water based dye pad) followed by drying in an air convection oven at a temperature of 140°C. for about 5 minutes. A portion of this webbing is reserved for testing as a control. The balance of the webbing is powder coated with a UV light absorber and heat treated in accordance with Example 1 above. It is anticipated that the webbing with the light absorber diffused therein will have significantly better UV stability than the control webbing.

Alternatively, the stuffer yams could be made from PEN yams of 1000 denier/ 192 filament zero twist, generally made in accordance with the teachings of U.S. Patent 5,397,527. It is anticipated that similar results would be obtained. EXAMPLE 7

During the beaming (2000 m/min) of 200 ends of PET 1000 denier/192 filament zero twist yam (1000-192-00-1X50, AlliedSignal Inc.), approximately 0.1 to 0.3 wt% of an epoxide powder (Epon 1001F, Shell) is electrostatically deposited on the yam ends. The yam ends are then passed through an air convection oven at a temperature above the melting point of the epoxide powder and above the T g of the PET ya but below the melting point of the PET yam for

a time period of about 1.5-2.0 minutes. The powder is expected to diffuse into the yam. The ya is then taken up. Subsequently, the yams are twisted into 1000/3, 8.5 X 8.5 tpi cords, which are then treated with a conventional resorcinol- formaldehyde-latex coating (see U.S. Patent 4,054,634) and tensilized by a conventional tensilization procedure. The adhesion between the resulting cord and rubber is tested by a peel adhesion test where the peel force and visual rating of the amount of rubber remaining on the cord is recorded. Any conventional test used by tire manufacturers is acceptable, e.g., the adhesion test disclosed in U.S. Patent 3,718,587 and further described in U.S. Patent 4,054,634, both of which are hereby incoφorated by reference. Peel adhesion is expected to be satisfactory.

TABLEHI. DYEBATHFORMULATIONS-DYES

Symbol Hue Color Index # Amount (g/L)

S Scarlet Disperse Blue 27 0.873

Disperse Red 73 13.65

Disperse Orange 29 5

Disperse Yellow 42 0.53

MA Med Antelope Dorospers* Yellow KLSR 21.45

Dorospers* Red KRG 11.82

Dorospers* Blue AGAF 18

B Dark Blue Terasil Navy 10

G Gray Disperse Yellow 42 2.806

Disperse Blue 80 2.092

Disperse Red 86 2.301

Dorospers Blue KGLFN 3.551

A Antelope Disperse Yellow 42 3.044

Disperse Blue 80 1.59

Disperse Blue 27 1.804

Disperse Red 302 1.958

*proprietary dye mixtures available from M. Dohman GMBH & Co. KG

TABLE IV. UV Testing Results For PET Seatbelt Webbing Treated with 2.4 dihvdroxybenzophenone

# Color Fumed Silica UV3000 Dye Fading wt% wt% 225kJ/m2 450kJ/m2 Delta E/GS Delta E/GS

1 MA 0.0 0 2.7/4 4.0/4

2 MA 0.2 0.38 1.6/4 2.3/4

3 G 0.0 0 2.4/4 5.3/3.5

4 G 0.2 0.62 1.1/4.5 2.1/4.5

5* S 0.0 0 3.0/4 6.4/3

6* S 0.2 0.37 2.4/4 5.3/3

7 MA 0.0 0 3.0/3 -

8 MA 0.5 0.49 1.9/3-4 -

9 A 0.0 0 3.3/2-3 -

10 A 0.5 0.32 1.6/3-4 -

11 S 0.0 0 3.8/2 -

12 S 0.5 0.44 2.4/3-4 -

13 B 0.0 0 12.5/1 -

14 B 0.5 0.30 9.7/1 .

*average of two samples

Table V. UV Testing Results for Treatment of Dyed PET Seatbelt Webbing

(2,4-dihvdroxybenzophenone)

Color Fumed Silica UV3000 Dye Fading wt% wt% 225kJ/m2

Delta E/GS

1 S 0.0 0.00 4.0/3 2 S 0.0 0.17 3.54/3-4 3 MA 0.0 0.00 2.5/3-4 4 MA 0.5 0.73 1.7/4 5 S 0.0 0.00 3.7/3-4 6 S 0.5 0.21 1.7/4 7 B 0.0 0.00 14.3/1-2 8 B 0.5 0.34 7.2/2-3

Table VL Concentration of Uvinul 3000 in Greige Webbing Determined bv Extraction and GC Analysis

Uvinul 3000

Loading Voltage Sample Location (wt%) Ratio Waφ/Weft

High left 1.25

65 kV right 1.31 waφ 1.30 2.17 to 1 weft 0.60

Medium left 0.60

50 kV right 0.61 waφ 0.84 2.90 to 1 weft 0.29

Low left 0.29

36 kV right 0.27 waφ 0.34 2.83 to 1 weft 0.12

Control left 0.00

O kV right 0.00 waφ 0.00 — weft 0.00