Machine-washable Metallized Fibrous Article And Method Of Making Same

Abstract

Fibrous article with heat-and-light reflecting quality provided by a metal coating on synthetic fiber substrates. The metal coating is undercoated and overcoated with resin systems. The article thus produced has functional heat and light-reflecting quality and decorative quality due to the metal coating of the fiber substrates due to the consistent with substantially retaining hand and softness of the fibrous article. The article is machine washable (i.e., retains its metal coat), abrasion and mar resistant, water repellent and dry cleanable consistent with high-moisture vapor transmission of the article (breathability).

Description

This invention relates to fibrous articles e.g., fabric (including woven, nonwoven or bonded or felt and including also a "beam" of fibers, a fibrillated or slit film) or a single fiber (including filament or yarn) to be formed into fabric and particularly to fibrous articles coated with metal to provide heat and light reflectance for decorative and functional (insulation and reflection) purposes. Related applications are Ser. No. 794,399 filed Jan. 24, 1969 now abandoned and Ser. No. 796,930 filed Feb. 5, 1969, both of common assignment with the present application.

The principal known fabric or fiber metallizing methods are (1) application of metal flakes in a plastic matrix, e.g., U.S. Pat. Nos. 2,630,620; 2,767,104 and 3,220,871 embodied Milium (registered trademark of Deering-Milliken Company) and (2) vacuum metallizing of a fabric or fiber, e.g., British Pat. Nos. 663,251; 721,879; 800,093; 816,906; and U.S. Pat. Nos. 2,912,345; 2,921,864; 2,907,678 and German Pat. No. 1,182,631 embodied in Metalon and Insalume (registered trademarks) fabrics (see Man Made Textiles Magazine-Jan. 1965 and Textile World Magazine-May 1965).

Both of these processes have significant limitations in regard to abrasion and mar resistance and launderability of the metal coating and/or moisture vapor transmission (breath ability). It is the primary object of this invention to provide commercially sufficient machine washability to a metallized polyamide (nylon) fibrous article as measured by visually observed retention of substantially all metal throughout the class II machine washability test of the American Association of Textile Chemists & Colorists (AATCC) consistent with retaining full breathability of the article. It is a further object of the invention to similarly improve other metallized synthetic fibers.

It is a further object of the invention to provide improved metallized fibrous articles characterized by improved abrasion and mar resistance, corrosion resistance, launderability, dry cleanability and water repellence consistent with high-moisture vapor transmission of the articles.

It is a further object of the invention to provide very high heat and light reflectance consistent with the foregoing objects.

It is a further object of the invention to provide an economical method of manufacturing such an article.

In general the improved fibrous article is made by precoating a fibrous article with a resin, metallizing the fibrous article in a vacuum chamber, removing the article from the vacuum chamber and top-coating it with a hydrophobic resin.

The process may be practiced on individual fibers such as monofilament fiber or yarn or slit or fabrillated film, which fibers are later formed into a fabric or felt, or practiced directly on a woven or bonded fabric or felt. The latter is preferred in cases where abrasion of weaving or bonding would remove metal coating despite resin protection e.g., in working with glass fiber substrates. The fiber involved should be synthetic but maybe part of a mixture of natural and synthetic fibers as in cotton-polyester woven fabrics. It is preferably wholly synthetic, preferably nylon, to realize the machine washability object to the highest degree.

Preferably the metal is applied to a thickness of about 10.sup..sup.-6 inches but may be as thin as 10.sup..sup.-7 or as thick as 10.sup..sup.-4 inches. The metal forms a single-thin film continuous layer along the individual fibers on at least one side of the fibrous article but without bridging gaps or openings between fibers in the article, to leave the breathability (moisture vapor transmission) of the article unhindered. The continuity of the film provides a better reflectance than a flake coating or a similar metallized film which simulates a flake coating due to crocking or crazing or removal of intermittent portions thereof due to abrasion or laundering or the like. The metal is vapor deposited, preferably vacuum deposited; it may be applied also through sputtering, pyrolytic or chemical vapor deposition or electroless vapor plating. Broad areas of the substrate may omit metal (through masking during deposition or removal of metal) for functional or decorative purposes.

The invention will be best understood from the following specific description taken in conjunction with the accompanying drawings wherein

FIG. 1 shows a portion of a woven fabric with one of the fibers in cross section and

FIG. 2 shows a typical textile process flow chart including as a portion thereof the use of the present invention.

In FIG. 1, the fibers shown in the article W (a woven fabric) are warp W and fill F with a high spot of the weave indicated at H. In the cross section, it is seen that the fiber comprises in this instance a monofilament synthetic, e.g., nylon (polyamide). A first under-or base-coat layer 12 of resin surrounds the fiber substrate. A midlayer 14 of metal is deposited over the base-coated fiber and a topcoat of hydrophobic resin 16 imparts water repellency.

The metal layer is applied by vacuum evaporation of metal and condensation of it on the fibrous article W. The metal vapors move in the direction M, through crossover points of the fabric as indicated at C are masked and receive no metal. However such points do receive top and base-coats if applied by immersion.

The fibrous article substrate is preferably, and with distinct advantage in the combination selected from nylon and polyester (e.g., Dacron brand) fiber. The fiber may be in the form of multifilament yarn or in monofilament form, but the latter is particularly advantageous in connection with the invention. A woven fabric substrate provides the best utilization of the invention's breathability retaining and high-reflectance characteristics.

The base coat layer 12 has a weight of 3-15 percent of the weight of the fibrous article (nylon fabric) and conforms to individual fiber surfaces, essentially without bridging adjacent fibers. The base coat is the polymenzation product of a hydrophillic polar unsaturated resin deposited in an emulsion bath and cured after deposition to form a surface coating on the fiber of improved level (smoothness) compared to the uncoated surface. The midlayer 14 of vapor deposited metal has sufficient thickness, as indicated above, to afford reflectances to light and heat radiation. Curing of the base coat should be complete so that it does not outgas during metallizing and interfere with metal adhesion. The top coat layer 16 is a cured hydrophobic resin with a weight of 0.5 to 5 percent of the fibrous article weight (including base coat and metal).

It is preferred and distinctly advantageous to have the top coat extend beyond the metallized area of the fibrous article to prevent edge attack by water in washing or usage of the article. Preferably the top coat surrounds the fibers. The base coat should also extend beyond the metallized area, under the top coat and preferably completely surrounding the fibers to provide a bondable surface for the top coat.

FIG. 2 diagrammatically illustrates the method of producing the machine washable metallized fibrous article of the invention. The diagram in part includes steps beyond the intended scope of the invention and old in the art, which are listed for purposes of establishing context of the invention.

Step A is conventional production or selection of fiber.

Step B is convention consolidation of fibers through weaving, bonding or the like.

Step C is the conventional cleaning and sizing e.g., "scour and heat set" of the fibrous article whether it be a fiber or fabric. Conventional textile processing procedures are involved and the resultant fibrous article is then said to be "ready for finish" e.g., through water proof coats, "hand" and finish modifying coats, strengthening coats, etc. If a fiber is to be eventually incorporated into a fabric it is preferable to complete the fabric production prior to the coating steps listed below to avoid damage to the coatings through abrasion, heat and chemical attack inherent in weaving procedures.

The present process invention includes as a first step (d) the precoating of the fibrous article. Preferably, this is done by immersion in an emulsion containing an acrylic resin in prepolymer form, squeezing (or otherwise removing excess emulsion pickup) and heating in an air oven to dry and polymerize the resin coat. It is preferred to support side edges of a long web on a tenter frame during this curing step. However the step may include other means of application and drying and choices of coating offering equivalent functioning in the total coating system described herein. To the extent practical, it is preferred to consolidate portions of (or eliminate redundant portions of) the steps of cleaning and sizing (c) and of precoating (d). For instance, the conventional cleaning step which generally involves immersion in a solvent cleaner, rinsing and drying could be modified to insert the precoating immersion step after rinsing, and before drying (heat-set sizing) to eliminate one redundant drying step.

The metallizing step involves placing the precoated fibrous article in a vacuum chamber, evacuating the chamber, outgassing the precoated fibrous article if necessary and then exposing the fibrous article to a source of evaporating metal in the chamber which metal condenses on the fibrous article. In commercial practice a roll of fabric yard goods constitutes the fibrous article and it is metallized in apparatus of the kind shown in U.S. Pat. No. 2,971,862 of Baer et al. The roll of goods is unrolled, passed over the metal source at speeds of several hundred feet per minute and rerolled. Prior to metallizing the goods should be unrolled and rerolled in vacuum to assure freedom from outgassing. It is sufficient if the outgassing does not raise chamber pressure above 10-.sup.3 torr. For small scale runs, a bell jar coater can be used with no relative movement of substrate (the precoated fibrous article) and metal source. The metallization increases opacity by about 75 percent. It is checked for adequate adhesion by the conventional Scotch tape test. At this point, the metallized article is hand washable and dry cleanable.

The metallized fibrous article is then topcoated preferably by immersion in a solution containing a silicon resin in prepolymer form, squeezing and heating in an air oven to dry and polymerize the resin, as in the precoat process. This renders the article machine washable and water repellent.

Subsequent steps can include cutting, stitching and other processing of the fibrous article.

The preferred embodiments of the invention are now further illustrated through the following nonlimiting examples.

EXAMPLE I

A scoured and heat set nylon woven fabric cloth of 90 .times. 108 taffeta weave was precoated by immersion in a bath containing the following constituents (with percentages indicated on a weight basis):

Rohm & Haas HA-8 acrylic emulsion (50% solids in water) 30 % oxalic acid catalyst 0.15% Philadelphia Quartz "N" sodium silicate 0.25% water balance

The bath was maintained at a temperature of 75.degree. F. The cloth was squeezed between nip rolls after immersion and passed through a drying chamber, containing air heated at 315.degree. F., in 90 seconds. The precoating produced, after drying, a solids pickup of 6 percent of weight of the original cloth.

After precoating, the cloth was passed through a vacuum coater and vacuum aluminized to produce a metal coating of about 10-.sup.6 inches on one side. The coating corresponds to what would be a 2 ohm per square coating on a film substrate.

Then the cloth was immersed in another bath having the following ingredients (by weight):

Silicon (Dow Corning FC-227) 30 % Catalyst (Dow Corning 27) 0.6% Adhesive (Dow Corning X(-4-2067) 0.9% Toluene balance

The bath was at 75.degree. F. Drying was accomplished as in the precoat step to produce a solid weight pickup of 1% (based on the precoated and metallized cloth).

The cloth was successfully machine washed in accordance with AATCC-II Test. No loss of metal was observed. The fabric was as breathable as before treatment.

EXAMPLE II

Processing as in Example I with a topcoat mix of

Silicone 20 % Catalyst 0.4% Adhesive 0.6% Toluene balance

(including metallizing and base coating as in I) was apparently similarly successful on white nylon cloth, but showed spots of blue in metallized blue cloth after washing, leading to the observation that the total coating system cracks or abrades at high spots (which is functionally acceptable but esthetically less desired).

EXAMPLE III

The results of Examples I and II were repeated in processes in which the base coat composition was varied to

UCar 891 acrylic-latex copolymer emulsion (50% in water) 20 % diammonium phosphate powder 0.5% water balance

Unsuccessful results re machine washability (i.e., failure to hold metal through AATCC-II Test) were obtained when the systems described in the above cited patent applications Ser. Nos. 794,399 and 796,930 were used. Unsuccessful results were obtained from:

a. direct metallizing with no base coat or top coat

b. precoat plus metallizing without top coat

c. top coated metallized cloths without precoat

d. acrylic base (as in Example I), metallize, acrylic top coat

e. silicon base, metallize, silicone top coat

It is desirable to assure uniformity of base and top coats, e.g., by the use of rubber surfaced nip rolls in the drying process and avoidance of abrasion in handling the cloth. In the above examples, handling conditions were less than ideal, including use of a chrome surfaced nip roll.

Addition of fireproofing agents to the base coat is also desirable. Chlorinated resin substitutes for the base coat resin accomplish this. Dispersion of fireproofing salts in the base coat as in Example III, above, is another way to accomplish the same result.

It is thus apparent that there is a synergistic effect in the combinations of the type illustrated in the above examples. Alternative ingredients for the base coat in lieu of or with acrylic and acrylic-latex polymers and copolymers are epoxy resins, polyvinyl chloride, cross linkable olefins, vinyl acrylic, vinylester copolymers. Alternative ingredients for the top coat in lieu of or with silicone are epoxy resins. Urethane resin top coat may be utilized but is less advantageous because it reduces transmission of infrared heat radiation to a substantially greater extent than silicone resin.

Water repellent resin coating systems are described in U.S. Pat. Nos. 3,081,193; 3,398,017; 3,326,713; 2,588,366; 3,434,875 and 3,076,926. See also the references cited above at the beginning of this specification.

The scope of the invention includes various other metals copper, zinc, tin, gold, silver, bright platinum, bronze, Wood's metal and equivalent metals. The metal coating may also be in sublayers providing iridescent reflective effects, but such sublayers would add up to a single-thin deposited layer in contrast the three dimensional structure of Milium coatings which have overlapping and nonparallel metal flakes in a plastic matrix.

Still further equivalents within the scope of the invention will be apparent to those skilled in the art once given the benefit of the foregoing disclosure. Accordingly it is intended that the foregoing disclosures shall be read as illustrative and not in a limiting sense.

Claims

What is claimed is:

1. A metallized fibrous article comprising individual synthetic fiber substrates which are coated with a multilayer coating comprising:

a. a base-coat layer of cured resin with a total weight of 3 to 15 percent of the article weight and conforming to individual fiber surfaces, essentially without bridging adjacent fibers, said cured resin selected from the group consisting of acrylic and acrylic-latex polymers and copolymers, epoxy resins, polyvinyl chloride, cross linkable olefins, vinyl acrylic and vinyl ester copolymers;

b. a midlayer of vapor deposited metal in sufficient thickness to afford reflectance to light and heat radiation;

c. a topcoat layer of cured hydrophobic resin with a total weight of 0.5 to 5 percent of the fiber weight and conforming to individual fiber surfaces, essentially without bridging adjacent fibers.

2. The article of claim 1 as a woven fabric.

3. The article of claim 1 with the fibrous article substrate composition selected from the class consisting of nylon and polyester.

4. The article of claim 1 with individual fiber substrates comprising monofilaments.

5. The article of claim 1 with the individual fiber substrates comprising multifilament yarn.

6. The article of claim 1 with the individual fiber substrates comprising a monofilament.

7. The article of claim 1 with the base-coat layer completely surrounding the fiber substrates in cross section.

8. The article of claim 1 with the hydrophobic topcoat layer completely surrounding the fiber substrates in cross section.

9. The article of claim 1 wherein the base-coat layer is acrylic resin and the topcoat layer is silicone resin.

10. The article of claim 1 wherein portions of the base-coat layer and the topcoat layer extend beyond the midlayer such that the base-coat and topcoat layers are directly bonded to each other.