US 3255492 A
Description (OCR text may contain errors)
J1me 1966 s. G. VELONIS ETAL 3,255,492
FORM FOR CASTING SEAMLESS, AMBIDEXTROUS PLASTIC GLOVES Original Filed May 31, 1961 :E' aili- INVENTORS 5 TA MAT! 5 GEORGE VEL alws HEREERT 5. SCHN/ 7'2 ER HNRY M- RICHARDSON 3,255,492 FORM FOR CASTING SEAMLESS, AMBIDEXTROUS 1 PLASTIC GLOVES Starnatis George Velonis, Opportunity, Wash., Herbert S.
Schnitzer, Longmeadow, Mass, and Henry M. Richardson, Somers, Coma, assignors to Galen Enterprises, Inc., Spokane, Wash, a corporation of Washington Original applications May 31, 1961, Ser. No. 113,962, now Patent No. 3,148,235, dated Sept. 8, 1964, and Jan. 15, 1964, Ser. No. 337,945, now Patent No. 3,197,786, dated Aug. 3, 1965. Divided and this application May 5, 1965, Ser. No. 453,299 The portion of the term of the patent subsequent to August 3, 1982, has been disclaimed 9 Claims. (Cl. 1841) This invention relates to casting forms, and more particularly forms for making seamless, ambidextrous plastic gloves, and is a divisional application of Serial No. 337,945, and application Serial No. 113,962, now Patent No. 3,148,235, which is a continuation-in-part of application Serial No. 796,850, now Patent No. 3,072,914.
It is the object of this invention to provide a glove dipping form constructed to produce well fitting, seamless synthetic plastic gloves whereby one form can be used to produce pairs of gloves.
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 perspective view of an ambidextrous fivefingered glove embodying this invention;
FIG. 2 is an elevational view of a dipping form for making ambidextrous gloves such as shown in FIG. 1;
FIG. 3 is a section taken along line 33 of FIG. 2; and
FIG. 4 is a section taken along line 44 of FIG. 2.
A glove embodying this invention, is shown generally at 19 in FIG. 1 on the hand of a wearer, represented generally at h. The glove is formed of a flexible fihn of fused pl-asticized 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 mils. F or surgical and similar purposes a film of approximately 2 to 3 mils in thickness has been found suitable. Preferably the outer surface of the glove 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 coating 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 mold or form.
Methods of making gloves embodying this invention include utilizing dipping forms such as generally indicated at 20 in FIG. 2. The dipping form 20 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.
under these circumstances aluminum would be the preferable material. However, when the fusing of the plastisol is carried out in a liquid medium, it is preferable that the form be made of a material which is a poor heat conductor suchas porcelain or filled epoxy resin forms.
The form 20 shown in FIGS. 24 comprises a met-a- I United StatesPatent carpal portion 24, finger forming portions 26, and a thumb forming portion 28 extending from the metacarpal portion. The metacarpal, finger and thumb portions of the form are all disposed in a common plane indicated at a in FIG. 3, which is the plane of symmetry of the form.
The fingers and thumb of the form are characterized by horizontally elongated cross sectional configurations, the larger dimension b thereof being disposed generally at right angles to the plane a. In spite of this unusual configuration, the periphery of the fingers and thumb are approximately equal to the periphery of the fingers of the human hand for which the glove is intended. The spacing 0 (FIG. 3) 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 30 in FIG. 4. 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 these geometric relationships have been described in connection with the form 20, naturally the glove 10 is characterized by the same relationships. The glove comprises a metacarpal portion 34, finger stalls 36 and a thumb stall 3-8. Both the finger and thumb stalls extend from the metacarpal portion with their longitudinal axes generally parallel and lying in a common plane which is the plane of symmetry of the glove. In general the opposite surfaces of the metacarpal portion 34 of the .glove lie in spaced planes converging toward the finger stalls. With this construction a very nice fitting ambidextrous glove is provided. Of course, when fitted on the hand, as shown in FIG. 1, the glove being flexible assumes the hand contour of the wearer.
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 so lution for about 15 minutes. This etched or otherwise finely roughened surface of the form is indicated in FIG. 2.
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. To keep draining time to a minimum for economic reasons, the viscosity of the plastisol should be about 1200 cps., or less, at 20 C., but higher viscosity up to somewhere in the neighborhood of 3000 cps. can be used with increased 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 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, sufficient 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 Division 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, non-slip surfaces.
In one method of carrying out the invention, the form is dipped in the plastisol to a depth generally indicated by the line 22, representing the open edge of the finished glove. The form is then 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 effect simultaneously 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 of the form is fine and insufficient 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 represented at 18 in FIG. 1. 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 be comes the outer surface of the glove, and this relation of the surfaces is preferably maintained in the use of the glove. I
In carrying out the method described above, after the form is dipped in plastisol and drained, the so-co'ated form is heated to fuse the plastisol. The step of heating may be accomplished 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.
As mentioned above, when the step of fusing the plas tisol 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.
Inaddition 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 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 inserted 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.
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 glove of the invention provides a high degree of tactile sensitivity combined with a relatively loose fit. This combination of sensitivity without tightness is an important aspect of this invention.
In addition to the function played by the described roughened 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, formed by a groove 27 provided in the form adjacent the dip line 22, gives a slight increase in stiffness adjacent the lower edge of the glove facilitating the donning and removal of the glove.
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 100% 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-100, 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. Formfor casting gloves comprising a metacarpal forming portion and finger and thumb forming members extending from the metacarpal portion, the longitudinal axes of said finger and thumb members being generally parallel and lying substantially in a common plane.
2. Form for casting gloves comprising a metacarpal forming portion, and finger and thumb forming members of non-circular cross section extending from the metacarpal portion, the longitudinal axes of said finger and thumb members being generally parallel and lying in a common plane which is the plane of symmetry of the form.
3. Form as set forth in claim 2 in which said form has an overall mat surface.
4. Form as set forth in claim 3 in which said finger and thumb members are of horizontally elongated cross sectional configuration with the larger dimension thereof being disposed transversely of said plane.
5. Form as set forth in claim 4 in which the distances between each of said fingers and thumb equals approximately the corresponding distances of the human hand, the overall width of said finger and thumb members being no greater than said metacarpal portion, said form having an overall mat surface.
6. Form for casting plastic gloves comprising 2. metacarpal forming portion and finger and thumb forming members extending from the metacarpal portion, the longitudinal axes of said finger and thumb forming members being generally parallel and lying in a common plane, which is the plane of symmetry of the form, said form being made of aluminum which is roughened to impart a mat surface to plastic gloves cast thereon, said finger forming members being characterized by a horizontally elongated cross sectional configuration with the larger dimension thereof disposed generally nomal to said plane of symmetry, the maximum width measured across the finger and thumb portion of the form being not greater than the width ofthe metacarpal portion.
7. Form for casting synthetic plastic gloves as set forth in claim 6 in which said form includes a groove disposed to provide a wrist bead on gloves cast thereon and in which the portion of said form between said finger forming members is convexly curved.
8. Form for casting gloves comprising metacarpal forming portions and laterally spaced finger and thumb forming members extending in generally parallel relation from the metacarpal portion, said members being characterized by a horizontally elongated cross sectional configuration with the larger dimension thereof being disposed transversely to the larger dimension of said form.
9. Form for casting gloves comprising a metacarpal portion and finger portion, said finger portion including finger and thumb forming members extending from the metacarpal portion, the longitudinal axes of the finger and thumb forming members being generally parallel and lying substantially in a common plane, the outer surface portions of said finger and thumb forming members defining in part a boundary of the finger portion of said form, the circumference of the metacarpal portion of said form being greater in length than said boundary.
References Cited by the Examiner UNITED STATES PATENTS 1,163,053 12/1915 Williams 1841 T184954 5/ 1916 Hoffman.
1,193,883 8/1916 Emery.
1,369,341 2/1921 Kearns.
1,458,185 6/1923 Hem-phill 18-41 1,951,402 3/1934 Gammeter 1841 2,078,093 4/1937 Miller et a1. 1841 2,078,913 4/1937 Strickhouser et a1. 18-41 XR 2,189,966 2/1940 Spanel 18-41 XR 2,344,960 3/1944 Beal 18-41 References Cited by the Applicant UNITED STATES PATENTS 2,747,227 5/1956 Reuter.
OTHER REFERENCES Annual Report 1964, Lightweight Plastic Gloves, Galen Enterprises, Inc., Spokane, Washington.
WILLIAM J. STEPHENSON, Primary Examiner.