US3148235A - Method of making plastic gloves - Google Patents

Description

Sept. 8, 1964 s. G. VELONIS ETAL 3,148,235

I METHOD OF MAKING PLASTIC GLOVES Filed May 31, 1961 2 Sheets-Sheet 1 INVENTOR5 STAMATIS GEORGE vewzws HERBER 's-scmwrzen HENR v RICHARDSON A T TORNE Y3 Sept. 8., 1964 VELONIS ETAL emos OF MAKING PLASTIC GLOVES 2 Sheets-Sheet 2 Filed May 31, 1961 INVENTORS STAMATIS 6OR6 V'lON/S HERBERT s. scHNrrzER HNRY M. RICHARDSON BY 8 M ATTORNEYS United States Patent This invention relates to moisture-impervious gloves. This is a continuation-in-part of an earlier application, Serial No. 796,850, filed March 3, 1959, now Patent No.

One object of this invention is to provide a method for making low cost, lightweight, moisture-impervious plastic gloves of a character which provides a high degree of touch sensitivity for the hands of the wearer.

It is another object of this invention to provide improved methods for manufacturing gloves of the above type which efifect substantial production economies, and wherein the method produces gloves having non-blocking characteristics superior to those made by prior processes.

The above and other objects of the invention will be more apparent from the following description with reference to the accompanying drawings in which:

FIG. 1 is a generally perspective view of a glove having a thumb and two finger stalls and embodying this invention, parts being broken away;

FIG. 2 is a plan View of a dipping form for producing the glove of FIG. 1;

FIGS. 3 and 4 are generally perspective views showing modifications of the form shape;

FIG. 5 is a fragmentary diagrammatical cross sectional view of the glove film and the surface portion of the form with the dimensions greatly magnified;

FIG. 6 is a perspective view of an alternative type of dipping form;

FIG. 7 is an elevational view of a dipping form for a five-fingered glove;

FIG. 8 is a perspective view of an ambidextrous fivefingered glove;

FIG. 9 is a perspective view of another alternative type of dipping form for making ambidextrous gloves such as shown in FIG. 8;

FIG. 10 is a section taken along line 1010 of FIG. 9; and

FIG. 11 is a section taken along line 11-11 of FIG. 9.

One form of glove embodying this invention is shown generally at 10 in FIG. 1. The glove shown is seamless, comprising three finger-receiving stalls including a thumb stall 11, a first or index finger stall 12, a second finger stall 13, and a skirt or metacarpal-receiving portion 15.

The glove is formed of a flexible film of fused plasticized synthetic resin having a finely roughened or mat outer surface, as generally indicated at 17, and a relatively coarse, overall uneven inner surface, as generally indicated at 18, with an average film thickness which may be from 1 to 10 mils. For surgical and similar purposes a film of approximately 2 to 3 mils in thickness has been found suitable. The ratio of the peripheral dimension of the free edge of the skirt portion 15 to the distance between that edge and the base of the finger stalls 11-12-13 is between 3 and S-to-l, preferably, and as shown this ratio is approximately 4.6-to-1. Preferably the outer surface of the glove "ice is provided with an annular rib 16 spaced a short distance from the free edge of the skirt.

The preferred material for the glove is plasticized polyvinyl chloride resin, but it will be understood that other flexible resin systems may be used.

In general, the glove is formed by applying a thin coat ing of a suitable liquid solution, dispersion or latex to a form or mold, fusing, drying, or curing the coating, and then stripping the glove inside out from the form or mold.

Methods of making gloves embodying this invention include utilizing dipping forms such as generally indicated at 20. The form is made from a suitable material, such as aluminum, which may be sheet stock about inch thickness, having a portion 21 for attaching the form to conventional dipping instrumentalities, and conforming beyond a normal dipping line 22 to the form of the glove generally shown in FIG. 1. This particular form includes portions 23, 24 and 25 lying in a common plane with a portion 26. The portions 23, 24 and 25 form respectively the three- finger stalls 11, 12 and 13, portion 26 forming the skirt portion 15. The edges 28 of the form are carefully rounded and a groove 27 provided adjacent the dip line 22, to form the head 16 on the skirt of the glove. The coplanar relationship of the finger and metacarpal portions provide a form for making ambidextrous gloves such as shown in FIG. 1.

To form a mat surface 17 on the outer surface of the glove, the surface of the form 20 is first polished and then finely roughened as by caustic etching, vapor blasting, anodizing or by a combination of these procedures, or by other suitable methods which do not impart a degree of roughness tending to produce areas of porosity and low strength in the film cast thereon. By these procedures, the surface of the form remains even but dulled, that is, its luster or gloss is removed. If the form 20 is made of aluminum, a satisfactory etch may be obtained by immersing the polished form in a 5% sodium hydroxide solution for about 15 minutes. This etched or otherwise finely roughened surface of the form is diagrammatically indicated at 29 in FIG. 5.

The form 20 is then dipped in a low viscosity deaerated plastisol, the polyvinyl chloride being dispersed in any of the well known plasticizers used for the purpose. For gloves intended for clinical use, the plasticizers should be such as are approved as non-toxic by the Food and Drug Administration. The viscosity of the plastisol should be about 1200 cps., or less, at 20 C. to keep drainage time to a minimum for economic reasons, but higher viscosity up to or somewhat about 3000 cps. can be used by increasing the drain time. In accordance with this invention plastisols are used to obtain the desired coarse, irregular, overall inner surface 18 of the glove in which a minor portion of the granular resin particles in the dispersion is greater in diameter than the average thickness of the glove forming film. When the plastisol is to be cast and fused on the form to about a 2 to 3 mil average film thickness, the major portion of the dispersed resin particles should be of approximately that diameter or less, together with a predetermined minor percentage of particles of about 5 mils in diameter, suflicient in quantity and distribution to provide the coarse, irregular surface 18. Plastisol suitable for the purpose of the invention is commercially available from the Borden Co. Chemical Div. under the trade name Reslac 2336-360. In general,

prior practices have involved application of a coarse textured material or particulated matter, such as flock, to the surface of a film or coating to obtain non-blocking, nonslip surfaces.

In one method of carrying out the invention, the form 20 is dipped in the plastisol to a depth generally indicated by the line 22, representing the desired edge of the skirt of the finished glove, removed from the plastisol and allowed to drain for a period of time sufficient to leave a plastisol film having the desired thickness on the form. The so-coated form is then heated to a temperature of about 450 F. for a period of 3 to 4 minutes to fuse the dispersed resin of the plastisol and to simultaneously effect the incorporation of the plasticizing dispersion medium into the resin. The form is then cooled to about 100 F. to permit stripping of the glove from the form. Lower or higher fusing temperatures may, of course, be employed for appropriately longer or shorter periods, if desired. Since the surface roughening 29 of the form is fine and insuflicient to accommodate a substantial flow of the plasticized resin into the surface interstices of the form, the larger particles of resin fuse to impart a relatively coarse characterizing overall roughness to the outer surface of the film on the form, as diagrammatically shown at 18 in FIG. 5. As previously mentioned, the glove is turned inside out as the glove is stripped from the form, thus the outer surface 18 of the film on the form becomes the inner surface of the glove and the surface 17 cast against the etched surface of the form becomes the outer surface of the glove, and this relation of the surfaces is preferably maintained in the use of the glove.

In carrying out the method described above, after the form is dipped in plastisol and drained, the so-coated form is heated to fuse the plastisol. The step of heating may be accompilshed in any suitable manner, such as by placing the form in a heated atmosphere or by dipping the form in a heated liquid fusing medium.

When the step of fusing the plastisol is carried out in a heated atmosphere, such as an oven, it is preferable that the form be a good conductor of heat, such as aluminum and the like. However, when the gloves are manufactured by a method wherein the fusing step is carried out in a liquid medium, this consideration loses its significance and, in fact, it is preferable that the form be made of a material which is a relatively poor heat conductor so that it will remain at a relatively low temperature during fusing. This means that the glove can be stripped from the form without waiting for the form to cool, as described above.

In addition to reduction in the time required before the completed gloves can be stripped from the form, fusion of the plastisol by dipping in a heated liquid also provides for a reduction in the time required for fusing the resin and thus effects a substantial increase in the number of gloves capable of being produced by a given form. The decrease in fusing time is realized by the superior heat conductivity of a heated liquid over heating in air, which is a poor heat transfer medium. While the rate of fusion is directly proportional to the temperature, when the fusion is carried out by heating in air, the temperature must be limited to prevent undesirable evaporation of the plasticizer. When the glove is heated in a dry atmosphere, unless the temperature and the time are carefully controlled, evaporation of the plasticizer will occur, particularly at the finger tip portions of the glove and these portions of the film can become brittle.

Fusion by dipping in a suitable liquid overcomes the problem of plasticizer evaporation and permits marked reduction in the fusion time. The only limiting factor in the temperature of the liquid is that the heat exposure cannot exceed the heat stability of the resin.

The fusing medium may be any suitable liquid which is a non-solvent for the plasticizer and the resin of the plastisol and one which preferably has a boiling point not lower than the fusing temperature of the plastisol. In

addition, it is preferable that the liquid be one which will drain or evaporate quickly from the surface of the glove without leaving an undesirable residue so that the glove may be stripped from the form and packaged without further processing. Moreover, it may be desirable to select a liquid which is water soluble so that if necessary, it can be easily washed from the surface of the glove. If necessary, drying of the glove on the form may be expedited by directing a stream of air at the form or by blotting excess liquid from the surface of the glove with a suitable absorbent material.

The following liquids have been found suitable for use in fusing a plastisol of polyvinyl chloride: Ethyleneglycol, diethyleneglycol, triethyleneglycol and glycerin. Other suitable materials which may be used to effect fusion of the plastisol include molten salt combinations or molten metals.

Using glycols of the type described above, a temperature in the range of 350 to 400 F. has been found suitable to effect a rapid fusion of plastisol. In this range no residence time of the form in the liquid is required. The form, carrying the film of plastisol, need only be in serted in the liquid and immediately withdrawn. Thus, a form made of non-conducting material does not become heated to any great extent as is the case where the fusion is conducted in an oven using a metal form. This is an important advantage in fusing by immersion, since the form can be immediately reused in a subsequent cycle without extensive delay.

For certain uses the shape and proportions of the glove shown in FIG. 1, as well as the roughening of the inner and outer surfaces of the glove, provides important advantages. In this form of the invention, the length of the glove is preferably such as to reach to the users wrist and as is apparent in FIGS. 1 and 2, the finger stalls 11, 12 and 13 flare relatively widely from the tips to the base of the fingers and this flaring is carried to the edge of the skirt 15. This construction results in a relatively loose, drape fit, providing room for housing the metacarpal portion of the hand and the fourth and fifth fingers pressed lightly against the palm, and makes for easy insertion of the hand into the glove with the thumb and first and second fingers in their proper stalls. This loose fit and in particular the wide flare of the skirt portion furthermore makes for easy removal of the glove after use one or two quick flicks of the hand and wrist being usually suflicient to remove the glove without assistance from the other hand. The glove may thus be removed directly into a suitable disposal receptacle, a substantial hygienic advantage particularly where the glove has been used for physical examination or surgical purposes. In any event the skirt portion may be thus turned inside out over the fingers and the glove removed without contamination.

The above described inner and outer surface characteristics of the glove provide gloves having a high degree of tactile sensitivity as compared with gloves made of thicker materials or having smooth or glossy surface characteristics.

The roughening 18 of the interior surface of the glove approximates that of the skin at the tips of the fingers} and when the gloved fingers are pressed against a surface being examined, or an article being grasped, the thin film of the glove is immobilized with respect to the fingers by the cooperating roughness or intermesh at the interface of the film particles and fingers. At the same time the roughness 17 of the outer surface prevents slipping of the outer surface of the glove over the surface being contacted.

In contrast with gloves formed of resilient materials such as rubber, where a stretched, tight fit is in large measure relied on to achieve sensitivity, the localized nonslipping contact through the thin flexible film, relatively loose fit on the hand, which characterizes the glove of the invention, provides the desired sensitivity and at the same time is an important factor in securing the added hygienic and economic advantages of a single-use article.

In addition to function played by the described rough ened surface of the glove, such surfaces prevent the undesirable tendency, known as blocking, of the film surfaces to adhere together in packaging and storage of the gloves, and makes unnecessary the resort to dusting with talc or the use of other parting materials to prevent blocking. The described manner of effecting the roughening of the surfaces further minimizes the tendency to the formation of pin holes in the cast film. The gloves may be sterilized, before or after packaging, by means of steam, chemical or other acceptable sterilizing methods.

The head 16 gives a slight increase in stiffness adjacent the edge of the skirt portion facilitating the flip-off removal of the glove, as above described, but while preferable, may be omitted.

Without sacrificing the desirable skirt width and length and the resulting drape characteristics, the skirt portion of the glove may, if desired, be given a curved edge, with a saving in glove material and weight, by bending the form about an axis, or axes, inclined from the plane of the form in a direction to reduce the dipping depth of the side portions of the form. For these purposes the form may be bent into the S or fan shape shown respectively in FIGS. 3 and 4, by way of example.

In FIG. 6 is shown an alternative type of form by which a glove, more nearly approximating hand shape, may be produced. As shown in FIG. 6, the form, which may be solid or hollow in cross section, comprises a dome shaped body portion 30 which includes a portion 32 on which the skirt portion of the glove is formed, and from which tapering, generally cylindrical stall forming portions 33, 34 and 35 extend, the several portions being dimensioned to provide a glove generally proportioned as previously described. The surface of the form of FIG. 6 is etched,

or otherwise finely roughened, as indicated at 36, in the manner and for the purposes previously described, and

the plastisol or other material may be applied thereto by dipping, spraying or pouring. The form of FIG. 6 has the advantage that it may be spun about its central axis, indicated at A, to speed the removal of excess material by a combination of gravity and centrifugal forces.

While for certain types of medical examination the three-stall glove of FIG. 1 may be preferable for the reasons described above, the invention is also applicable to a glove having a lesser or greater number of finger stalls. A dipping form for making gloves having a full complement of finger stalls and embodying the invention is shown at 38 in FIG. 7.

In FIG. 8 is shown a five-fingered glove 40 having a more or less form fitting metacarpal receiving portion. The glove is of seamless construction, as described above, and is provided with an overall finely roughened or mat outer surface 17 and a coarsely roughened inner surface 18, of the same characteristics described above. The glove 40 is formed on a dipping form 42 shown in FIGS. 9 and 10.

The dipping form 42 may be made of any suitable material such as cast aluminum, porcelain, or epoxy resin. The surface of the form is finely roughened by any suitable method which is compatible with the material selected for the manufacture of the form, such as caustic etching, vapor or sand blasting, anodizing and the like.

When the step of fusing the plastisol is to be accomplished in a heated atmosphere such as an oven, it is important that the form be a good conductor of heat, and under these circumstances aluminum would be the preferable material. However, as explained above, when the fusing of the plastisol is to be carried out in a liquid medium, it is preferable that the form be made of a material which is a poor heat conductor such as porcelain or filled epoxy resin forms.

The form 42 shown in FIGS. 9 and comprises a metacarpal portion 44, finger forming portions 46, and a thumb forming portion 48 extending from the metacarpal portion. The metacarpal fingers and thumb portions of the form are all disposed in a common plane indicated at a in FIG. 10, which is the plane of symmetry of the form.

The fingers and thumb of the form are of horizontally elongated cross sectional configuration, the larger dimension b thereof being disposed generally at right angles to the plane a. The periphery of the fingers and thumb are made approximately equal to the periphery of the fingers of the human hand for which the glove is intended. The spacing 0 between the fingers of the form is also made approximately equal to the corresponding dimension of the human hand and is curved as indicated at 50 in FIG. 11. The finger spacing must be approximately correct to make a properly fitting glove. While the finger spacing and peripheral size of the fingers is made approximately equal to the human hand, the arrangement of the finger and thumb portions of the form are such that their overall width w is not greater than the width of the palm portion of the form. This construction enables the glove to be easily stripped from the form, even though the glove material is not stretchable to any great extent. By this arrangement one dipping provides a form fitting ambidextrous glove which fits equally well on either hand enabling substantial reductions in mold costs.

While for reasons of simplicity, cost and ease of handling, plastisol is the preferred form of material, the glove may be similarly cast or dipped from solutions, latices of polyvinyl chloride, or other suitable resins. In these latter forms the resin and plasticizers may be in solution in a common solvent or dispersed in water as a common dispersing agent. In addition, polymerizable liquid resins, such as polyurethane and the like, may be used in carrying out this invention. Since roughening of the inner glove surface cannot be readily effected by variations in the resin particle size, roughening may be obtained by dispersing in the solution or latex particles of an inert insoluble granular material such as sand, pumice, thermosetting resin, and the like, the particles being larger than the desired film thickness. Such inert granular materials may be dispersed in the plastisol in lieu of the oversized resin particles.

Polyurethanes suitable for use in making gloves embodying this invention include polyurethane elastomers available in the form of reactive liquids which can be cured to a flexible film by heating, exposure to moist air, by the addition of curing agents, or by combinations of these methods. An example of such a polyurethane is Adiprene L-lOO, manufactured by Du Pont. Since polyurethanes have adhesive-like properties, a suitable mold release agent may be introduced in the liquid resin or applied to the dipping form to enable the cured resin to be easily stripped from the form. Alternatively, a

Teflon or silicone-polymer surfaced dipping form may be used. Diluents of a volatile nature may be added for viscosity control. Although polyurethane elastomers require a fairly long curing time, their toughness and abrasion-resistance are outstanding.

Having thus described this invention, What is claimed is:

1. The method of making a seamless glove possessing tactile sensitivity and non-blocking inner and outer surfaces which comprises applying to a glove form, having a finely roughened surface, a liquid film of a synthetic plastic containing particles of greater diameter than the desired average thickness of the finished glove, allowing excess material to drain until the desired Weight and thickness remains on the form, heating the form to consolidate the film, cooling the form, and stripping the finished glove therefrom.

2. Method of making synthetic plastic gloves possessing tactile sensitivity and non-blocking inner and outer surfaces comprising applying to a glove form, having an overall mat surface, a liquid coating of synthetic plastic material containing particles of generally greater diameter than the thickness of the finished gloves, allowing excess plastic to drain until the desired thickness remains on the form and heating the liquid coated form to'fuse said plastic.

3. Method of making synthetic plastic gloves as set forth in'claim 2 in which said plastic is a plastisol and in which the heating of said plastic is carried out by dipping the liquid coated form in a liqiud fusing medium heated sufliciently to consolidate said plastic, said fusing liquid being a non-solvent of the constituents of the plastic coating material.

4. Method of making synthetic plastic gloves as set forth in claim 3 in which said material is polyvinyl chloride plastisol.

5. Method of making seamless synthetic plastic gloves possessing tactile sensitivity and non-blocking inner and outer surfaces, comprising the steps of applying to a glove form having an overall mat surface, a liquid coating comprising a dispersion of inert particles in a polyurethane elastomer in liquid form, said particles being of generally greater diameter than the average thickness of the n G finished glove, curing the polyurethane coating on said form and stripping the glove, inside out from said form.

References Cited in the file of this patent UNITED STATES PATENTS 1,941,200 Chapman et al Dec. 26, 1933 1,945,256 Clarke Jan. 30, 1934 2,123,343 Rightsell July 12, 1938 2,670,473 Stebie Mar. 2, 1954 2,747,227 Renter May 29, 1956 2,779,025 Perry Jan. 29, 1957 2,847,676 Scott Aug. 19, 1958 2,838,759 Tassie June 17, 1958 2,854,695 Moreau Oct. 7, 1958 2,873,450 Brodeur Feb. 17, 1959 FOREIGN PATENTS Great Britain July 4, 1956

Claims (1)

1. THE METHOD OF MAKING A SEAMLESS GLOVE POSSESSING TACTILE SENSITIVITY AND NON-BLOCKING INNER AND OUTER SURFACES WHICH COMPRISES APPLYING TO A GLOVE FORM, HAVING A FINELY ROUGHENED SURFACE, A LIQUID FILM OF A SYNTHETIC PLASTIC CONTAINING PARTICLES OF GREATER DIAMETER THAN THE DESIRED AVERAGE THICKNESS OF THE FINISHED GLOVE, ALLOWING EXCESS MATERIAL TO DRAIN UNTIL THE DESIRED WEIGHT AND THICKNESS REMAINS ON THE FORM, HEATING THE FORM TO CONSOLIDATE

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