US3825435A

US3825435A - Flocking method utilizing in line mixing of adhesive

Info

Publication number: US3825435A
Application number: US00221607A
Authority: US
Inventors: H Hunt
Original assignee: Crown Crafts Inc
Current assignee: Crown Crafts Inc
Priority date: 1972-01-28
Filing date: 1972-01-28
Publication date: 1974-07-23
Anticipated expiration: 1991-07-23

Abstract

THE ADHESIVE APPLICATION RATHER THAN A SOLID FILM IS A FOAM AND THE PREPARATION OF THE ADHESIVE RATHER THAN IN LARGE BATCH MIXTURE IS IN SMALL BATCHES EASILY CONTROLLED AS TO DELIVERY AND FORMULATION AND MIXING AND FOAMING IS IN A FOAMING HEAD AND NOT IN SEPARATE AND ADDITIONAL OPERATIONS. CHEMICAL FEED PUMPS AND AN ADHESIVE FED PUMP DELIVER IN A PRE-CONTROLLED AMOUNT TO A MIXING AND FOAMING HEAD WHICH IS REFRIGERATED AND THE ADHESIVE MIXTURE IS FILTERED AND DELIVERED TO THE MACHINE FOR APPLICATION. THE CHEMICAL PUMP IS A SERIES 200 CHEM-TECH INTERNATIONAL AND THE ADHESIVE PUMP IS A MOYNO BY ROBBINS AND MEYERS, INC. A TYPIICAL ADHESIVE IS "RHOPLEX" E-358 FROM ROHM AND HAAS, PHILADELPHIA, PA.

AN IMPROVED METHOD OF PREPARING AND DIRECTING A SUBSTRATE MATERIAL FOR ELECTROSTATIC APPLICATION OF FLOCKING MEMBERS TO AN ADHESIVE TO PRODUCE A DENSE PILE FABRIC SUCH AS A VELVEL FABRIC, A BLANKET FABRIC OR A CARPET FABIC. A CONTINOUS SUBSTRATE MATERIAL IS DELIVERED FROM A ROLL AROUND A HEATED DRUM TO CONTROL MOISTURE TO AN ADHESIVE APPLICATOR ASSEMBLY WHICH EMPLOYS AN IMPROVED SYSTEM OF DELIVERING ADHESIVE AND CONTROLLING SAME ON THE SUBSTRATE. THE ELECTROSTATIC GRID SYSTEM COMPRISES HIGH VOLTAGE (H.V.) PLASTIC PIPE ELECTRODES ARRANGED DIAGONALLY TO THE LINE OF TRAVEL OF THE SUBSTRATE AND EACH PIPE HAS AN ELECTRICAL CONDUCTOR CABLE CONNECTED TO IT FORM A HIGH VOLTAGE SYSTEM. THE DIAGONAL ARRAGEMENT OF THE GRID SYSTEM IS WITHIN A GROUNDED FIELD OF METAL TUBING WHICH PRODUCES A WEAK ELECTROSTATRIC FIELD ABOVE THE H.V. ELECTRODES AND ELECTRICALLY REMOVES ANY EXCESS FLOCKING MATERIAL WITHOUT DAMAGING THE FLOCKING FIELD.

Description

H. D. HUNT July 23, 1974 FLOCKING METHOD UTILIZING IR LINE MIXING OF ADHESIVE 3 Sheets-Sheet 1 Filed Jan. 28, 1972 July 23, 1974 H, H NT 3,825,435

FLOCKING METHOD UTILIZING IN LINE MIXING OF ADHESIVE Filed Jan. 28, 1972 3 Sheets-Sheet :2

IE] go I 2 2 z nnnnnnn n United States Patent O U.S. Cl. 117-33 7 Claims ABSTRACT OF THE DISCLOSURE An improved method of preparing and directing a substrate material for electrostatic application of flocking members to an adhesive to produce a dense pile fabric such as a velvet fabric, a blanket fabric or a carpet fabric. A continuous substrate material is delivered from a roll around a heated drum to control moisture to an adhesive applicator assembly which employs an improved system of delivering adhesive and controlling same on the substrate. The electrostatic grid system comprises high voltage (H.V.) plastic pipe electrodes arranged diagonally to the line of travel of the substrate and each pipe has an electrical conductor cable connected to it from a high voltage system. The diagonal arrangement of the grid system is within a grounded field of metal tubing which produces a weak electrostatric field above the H.V. electrodes and electrically removes any excess flocking material without damaging the flocking field.

The adhesive application rather than a solid film is a foam and the preparation of the adhesive rather than in large batch mixture is in small batches easily controlled as to delivery and formulation and mixing and foaming is in a foaming head and not in separate and additional operations. Chemical feed pumps and an adhesive feed pump deliver in a pre-controlled amount to a mixing and foaming head which is refrigerated and the adhesive mixture is filtered and delivered to the machine for application. The chemical pump is a Series 200 Chem-Tech International and the adhesive pump is a Moyno by Robbins and Meyers, Inc. A typical adhesive is Rhoplex E358 from Rohm and Haas, Philadelphia, Pa.

BACKGROUND OF THE INVENTION (1) Field of the Invention Textiles and particularly flocked materials and especially flocked materials produced electrostatically.

(2) Prior Art Discussion Electrostatic production of flocked material is old and well known. Adhesives are mixed in large batches and delivered to the flocking apparatus. The prior art electrodes (field producing elements) are arranged at right angles to the material and for Widths of over 7 feet, because of sag, supports are required that interfere with the flocking and the accumulation of flock material above the substrate causes streaks. The accumulated material eventually falls onto the substrate causing a defect in the material. Sometimes opposing electrostatic fields cause an accumulation of flock material to be suspended for a period then released.

Usually in the flocking procedure the flocking adhesive is applied as or becomes an almost complete film impervious to air. This can be a serious disadvantage in clothing, bedclothing, and upholstery where moisture from the human body must escape and ventilation is desired. A porous adhesive solves the problem but is not easy to obtain by previous methods. Also, prior art flocking adhesive methods require a precoat on the substrate 3,825,435 Patented July 23, 1974 to prevent the flock adhesive from penetrating through the substrate, to produce a smoother flocking surface, and to permit the application of a thin coating of flock adhesive with conventional equipment thus keeping the finished weight of adhesive within an acceptable limit.

The usual method of mixing adhesives is the large batch method involving mixing a large batch for a period of time. This involves mixing, checking as to mixture, etc. and sometimes the correction of an incorrect batch. Incorrect batches cause delays and waste material, excessive clean-up, expensive mixing and handling equipment and more labor cost.

SUMMARY OF THE INVENTION By directing the material through electrodes in the form of plastic pipes arranged at an angle other than a right angle to the line of travel of the material streaks caused by the suppport structure of the previous grids are substantially eliminated.

Continuous mixing substantially eliminates the abovenoted problem of the adhesive not being properly applied and foaming reduces the problem of too solid a film on the substrate and no pre-coat is necessary. Also, the foamed adhesive does not penetrate and therefore can be controlled, including density control to relieve weight.

Large batch mixtures have been eliminated by the present use of in-line mixing where chemicals are metered. The adhesive is metered through a pump from a tank into a foam mixing head where air is used to foam. Pumps are used to distribute the chemicals and adjustments are simpler than in the batch method. Usually once the equipment is set there is less chance of error and less checking is required. Cleaning consists of attaching a water hose to the unit and flushing it out.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view top and bottom showing the movement of the material starting at the lower righthand and continuing from the lower left-hand to the upper right-hand.

FIG. 2 is a cross-sectional view through one of the electrostatic high voltage electrodes.

FIG. 3 is a top plan view of the high voltage electrode grid system.

FIG. 4 is a side elevation view of the grid system shown in FIG. 3.

FIG. 5 is a flow process diagram for the preparation and delivery of the adhesive used on the substrate.

FIG. 6 is a diagrammatic view of the components used in the flow diagram of FIG. 5.

FIG. 7 is a cross-sectional view of the foaming and mixing head equipment shown in FIG. 6.

FIG. 8 is an enlarged plan view of some of the elec trodes in FIG. 3.

FIG. 9 is an enlarged side elevation view with parts of the electrode support in FIG. 3 broken away.

FIG. 10 is an enlarged elevation view of the end of an electrode and support therefor.

DESCRIPTION OF PREFERRED METHOD OF AN APPARATUS FOR FLOCKING Referring initially to the apparatus shown in FIG. 1, a continuous substrate material 10 is delivered from a roll 12 supported on shaft 14 across guide rollers 16, 18 and in contact with and across applicator roller 20 in an open trough or pan 22 containing water which is applied to the substrate 10. The substrate 10 is a conventional material in the trade and may be cotton sheeting approximately 3.3 ounces per square yard of the sort that can be obtained from Bibb Mfg. Co. or Thomaston Mills.

After receiving the application of water and moisture from the roller 20 the substrate continues across and about roller 24 and around a large heated drum 26 rotatably supported on shaft 28 whereat the moisture in the substrate 10 is removed and the substrate 10 sheeting is ironed smooth to remove wrinkles and creases. Substrate 10 then continues guided across rollers 3-2, 34, 36 around a pull roller 38 and thence across an idler roller 40 about a speed control roller and dancer bar 42 to the adhesive applying means designated generally by reference numeral 44 at which place and time the adhesive to be mentioned hereinafter is applied. As will be apparent, it is applied in coherent form. The adhesive is delivered from a foaming nozzle 45 through a hose 46 on a traverse assembly 48 in front of a coating knife assembly 50 and the distribution of the adhesive across the width is obtained through the motion of the traverse assembly 48 and also as to thickness and/or weight by adjusting the gap between a rubber-covered back-up roller 52 and the coating knife 54 after the substrate 10' is directed across a direction changing roller 56. Knife assembly 50 comprises an adjustable doctor bar or knife to control adhesive thickness during adhesive application. Having received the adhesive the substrate 10 continues into the flocking chambers the first of which is designated generally by reference numeral 60 having a screened bottom hopper 62 thereon which contains a supply of flocking fibers or filaments distributed into the chamber defined by a wall structure 64 in which is located the electrostatic grid system 66 supplied from high voltage (H.V.) transformers 67 which creates an electrostatic field to electrostatically attract the fibers or filaments and direct them against the adhesive coating on the substrate 10. In conventional manner moving rakes in the hopper 62 sift the flocking filament through the screens. The flocking filaments or fibers fall free until passed through the high voltage grid system 66 whereat the filaments or fibers are overtaken by strong electrostatic field created between grid 68 and a ground plate 70. The flocking fibers or filaments are propelled by the electrostatic force at a high rate of speed thus embedding into the adhesive coating on the substrate 10 which is still tacky and will hold a high percentage of the fibers or filaments directed thereagainst. Two flocking zones are provided so as to obtain the desired density of flocking fibers or filaments embedded in the adhesive on the substrate 10 and the second flocking chamber 80 is identical to the chamber 60 in the first zone flocking chamber operation. A vibrator 71 helps align the flock and embed it into substrate 10 and to loosen excess flock.

After the substrate 10 leaves the flocking chambers there is a small amount of excess fibers and filaments that are still in the pile or on the surface and must be removed. This is done by beating the material, which is now designated by reference numeral 84, having received the pile thereon and changing character from the original substrate 10. Material 80 is beat with a beater bar rotating assembly 86 and loosens the unstuck flock fibers and filaments so that a vacuum system 88 can remove it. The flocking chambers 60, 80 are separated from the rest of the operation by walls or baflles constructed in the plant and designated by reference numeral '90, 92. Pile material 84 continues into a curing oven 96 where the acrylic adhesive is cured for 10 minutes at 300 degrees F. (example). The material 84 then continues through a series of rollers 98, 1.00, 102 through the oven 96 and therefrom in response to a speed control delivering the material 84 to a brush cleaning unit after having changed direction by means of a series of small rollers 110 through a dancer bar speed control roller 112 (same as roller 42, etc.) across rollers 114, 116, 118 to a brush cleaning unit 120 which includes a rotating brush 122 in contact with the nap or pile 84 fabric to remove any loose fibers and filaments and thence from there through a pull roller system 126 to a roller machine 128.

A typical flocking fiber or filament would be 5.5 denier rayon obtainable from American Viscose; .080-1050 long blended 50%50=% supplied by Precision Fibers, Inc. or Flock Industries.

A.C. GRID SYSTEM The AC. grid system designated generally by reference numeral 68 in FIG. 1 is designed to operate in the upper 10% of the power supply that is provided which is typically 50 kv. 40 ma. The grid system comprises a plurality of diagonally disposed electrodes which may be polyvinyl chloride plastic tubes (or PVC tubes) which act as resistors and are selected to obtain the strongest field possible while keeping the leakage through arcing at a minimum. The tubes are designated generally by reference numeral 150 in FIG. 3 and a typical tube in cross section is shown in FIG. 2. Each tube is an elongated plastic pipe 152 with an inner tube 154 to which is attached the electric cable 156 through the conduit 158 and through an end cap 160 on one end closing that end of the tube 152 and there is an end cap 162 on the other end. The tubes 152 are diagonally disposed from a rectangular frame 164 constructed from wood frame member 165 and each tube is supported by a Plexiglas tube support 166 in holes 167 on frame 164. The inside pipe 154 is a tube conductor which may be /2 inch thin wall conduit. The electrodes 152 are installed in the diagonal position permitting the electrodes 152 to be supported without interfering with the flock flow on the electrostatic field. Since they support at right angles to the material to be flocked there is no adverse effect to the electrostatic field or the finished product any reasonable number may be added to support the electrodes. This permits the size of the grid 68 to be extended to any width and length desired. Grid 68 includes a grounded field comprising a grounded conductor over each high voltage electrode 150 and the grounded conductors comprise steel tubing 170 located and supported in frames 165 in holes 172 at a distance above the electrodes 150 equal twice the distance between the electrodes in the grounded plate 84. This grounded field is to remove electrically the flock that accumulates on top of the electrodes 150 and to assist in the removal of any accumulated flock on the grid 68. There is provided a vibrator I168 which may be of the brand name Syntron.

The power unit (not shown) designed for electrostatic field production is a high voltage AC electrostatic source such as that provided by Peschel Instruments, Inc. of Industrial Park, 1412 Viscay Parkway, Cape Coral, Fla. 33904, according to Technical Bulletin Serial No. 4393 of Mar. 26, 1971, Model No. K60-2.4FL. This power unit is connected to the grid 68 in the manner instructed by the manufacturer. The grid system is designed, in one embodiment, to operate in the upper 10% of the power supply of about 50 kv. at 40 ma. The PVC tubes act as resistors and are selected to obtain the strongest field possible while keeping the leakage through arcing at a minimum.

ADHESIVE PUMPING AND FOAMING ASSEMBLY The adhesive preparation, pumping and foaming is illustrated diagrammatically by the flow chart shown in FIG. 5. There is a mixing and foaming unit designated generally by reference numeral 200 which eliminates large batch mixing common with flocking adhesive and is versatile in that the delivery and formulation is changed by a Substance: v1

5 acrilic which is 60% solids (no filler) having a typical formulation as follows;

I. a Parts E-358 Rhoplex 1 (60% solids-no filler) 1000 Catalyst A (curingcatalyst) 7 Ammonium hydroxide thickening reactant Acrysol ASE-60 1 (thickening agent) 10 Acrysol ASE-95 1 (thickening agent) 5 Ethylene' 'glycol (humectant) 20 123 21 9 u t f piex E-358 arr-- The adhesive;E-358, or any other suitable adhesive ,such as another acrylic, is pumped from reservoirs 210 b y means of aqpump such as the Moyno progressing cavity pump 212 from Robbins and Meyers, Inc., Springfield, Ohio, Bulletin No. 105-a, and compressed air is introduced from an air pump and supply apparatus 214 vvthru a line 216-into the foaming and mixing head made vby and obtainable from Textile Rubber and Chemical Company and sold as a latex foaming machine. The chemicals are supplied from three small tanks or

reservoirs

220, 222' and 224 each respectively containing a mixture (A), (B) and (C), as follows:

Pumps

202, 204, 206 and 212 are variable speed and can be controlled to control the amount supplied at any time. The compressed air is supplied into the system as itenters the, foaming head 200 which is a power driven mixing machine used to mix and foam latex. Foaming head 200 is driven from a small pulley drive 230 which turns shaft 232 in the housing 234 which is cooled and refrigerated by coils 236 from a refrigerating unit 240 which includes a cooling tank of water 242. All mixing of the adhesive is done at the head 200 thereby eliminating previous large batch mixtures. After formulation and mixing the adhesive mixture is forced under pressure of from about 40 p.s.i. to about 80 p.s.i. to and through a straining and filter arrangement 243 through a flexible hose that conveys the adhesive mixture to the applicator means comprising hose 46, coating knife assembly 50, etc. mentioned previously. Head 200 is provided with chemical in-

ports

250, 252 and an adhesive in-port 254. The foamed adhesive is forced out through the tube 256.

[Foaming head 200 has a rotor 248 with small blades 249 turning inside of internal blades 251 supported on the inside of the housing 234, thereby causing the agitation that produces the foam. Foaming head 200 is a common item of commerce and may be purchased on the open market.

While I have shown and described a particular form of my methods and apparati this is only for illustration of the preferred embodiments and does not represent the only forms since there are alterations, changes, amendments, variations, additions, substitutions, combinations, deviations and departures within the scope of this invention defined only by proper interpretation of the appended claims.

What is claimed is:

1. In a method of flocking a moving substrate material including the steps of: applying to the moving substrate material a coherent formulated mixture comprised of an adhesive, a curing catalyst, an adhesive thickening agent, a thickening reactant to react with the thickening agent, and a humectant, adhering a plurality of electroapplied flocking membersto the" mixture, and heating the flocked substrate to cure the mixture, the improvement comprising:

maintaining said adhesive in a first reservoir;

maintaining said adhesive thickening agent and said humectant in a second reservoir; maintaining said thickening reactant and said curing catalyst in a third reservoir; said reservoirs being isolated from one another; providing for changes in the formulation of said mixture to be applied to said substrate by separately and adjustably metering quantities of: said adhesive from said first reservoir, said adhesive thickening agent and said humectant from said second reservoir, and said thickening reactant and said curing catalyst from said third reservoir into a mixing head;

mixing, while so metering, said quantities of material supplied to said mixing head; and

while so mixing in said mixing head, delivering mixed coherent material of a selected formulation from said mixing head to said moving substrate.

2. The improvement according to claim 1 including the steps of introducing air into said mixing head along with said metered quantities from said reservoirs and foaming the mixture in said mixing head.

3. In a method of flocking a substrate material including the steps of: applying to the substrate a coherent formulated mixture comprised of an adhesive, an adhesive thickening agent and a thickening reactant, adhering a plurality of flocking members to the mixture, and heating the flocked substrate to cure the mixture, the improvement comprising:

establishing a first feed path for delivery of said adhesive from a first supply station toward said substrate;

establishing a second feed path for delivery of said adhesive thickening agent from a second supply station toward said substrate;

establishing a third feed path for delivery of said thickening reactant from a third supply station toward said substrate;

metering quantities of:

said adhesive along said first feed path, said adhesive thickening agent along said second feed path, and said thickening reactant along said third feed path into a mixing station providing a continuation of said first, second and third feed paths, where separately and adjustable metered quantities of said adhesive, adhesive thickening agent, and thickening reactant are continuously mixed together along their feed paths of travel toward said substrate to provide for changes in the formulation of said mixture to be applied to said substrate, and delivering the metered coherent mixture of a selected formulation provided at said mixing station to said moving substrate.

4. In a method of flocking a substrate material conditioned by a coherent formulated mixture, comprised of an adhesive, an adhesive thickening agent, and a thickening reactant, delivered onto the substrate, the improvement comprising:

delivering a metered coherent mixture of a selected formulation of said adhesive, adhesive thickening agent and thickening reactant onto said substrate, said metered mixture being provided by in-line mixing of separately and adjustably metered quantities of said adhesive, adhesive thickening agent and thick- 7 ening reactant delivered along independentfeed baths to a mixing head to provide for changes "in' thef formulation of said mixture?" 5. The method according to c1ai rn 4 Wherei rf saidtthickening reactant is supplied'along 'i'ts feed pathjwitha' cliring catalyst. i I

6. The method according to c1aim4 wherein said'fadhesive thickening agent is 'suppli'edlal o ngf its"fe d" iiith with a humectant. i

7. The method according to claim 4.inclfi'din'thesteps of introducing air into said mixing'head 'andf foaming the mixture therein. V

References" Cited UNITED STATES PATENTS 2,941,900 6/1960 Schrder-Stranz 117-105.5 3,049,439 8/1962 Cotfrnan 117105.5 3,097,764 7/1963 Loeser 117-105.5 3,105,745 10/1963 Vieli 117105.5 3,147,137 9/1964 Glass et a1. 117l05.5

, V 8 4/1965 P1353131; 1/ 1969 McGregor" 4/1969 MICHAEL SOF CifibU,