FILM WITH CAPILLARIES IN ANGLE
PREVIOUS TECHNICAL DESCRIPTION The present invention is found in the general field of perforated plastic films and refers especially to the perforation of plastic films. The invention relates particularly to plastic perforated films, to metal screens or molding elements used in the vacuum perforation of plastic films and to a method for manufacturing these screens. Perforated plastic films have many useful applications. They are used in gardens and farms to prevent the growth of grasses and weeds, while allowing moisture to be transmitted through the film to the ground beneath it. Perforated films have a multiplicity of regularly spaced openings, which allow the permeation of liquid and air or other fluids. These films can be used as a component of garments for sanitary purposes, such as towels, diapers or for cushion linings of hospitals, beds or sleeping bags, and the like. In such composite structures, an outer layer of the film, having the desired properties, is provided, which will be adjacent to the skin in a composite garment, and this garment also includes one or more layers of filler from a Absorbent fibrous material. An example of the use of a perforated film to obtain disposable diapers is shown in the patent of E. U. A., No. 3,814,101. A particular kind of perforated film is described by Thompson, US Patent No. 3,929,135, issued on December 30, 1975. Thomson teaches an absorbent structure with a top layer of a perforated film, characterized in that it has a series of small regular openings , spaced, in the form of tapered capillaries of certain dimensions. In the finished article, they are directed to the interior to be in intimate contact with a layer of absorbent fibrous material. The smooth side of the perforated film is thus, in use, in contact with the skin. The film, as described by Thomson, in the structure of the garment, as it is delineated, maintains a dry and comfortable condition, even after the transmission of fluids to the absorbent layer by the combined effects of absorption and resistance. to the posterior flow, as a result of the relative length and surface properties of the tapered capillaries. One of the above methods for vacuum perforation of plastic films is disclosed in U.A. Patent No. 3,054,148. Patenting describes a stationary drum having a molding element or screen mounted around the outer surface of the drum and adapted to rotate freely therewith. A vacuum chamber is used under the screen to create a pressure differential between the respective surfaces of the thermoplastic sheet to be drilled, to cause the plastic sheet to flow into the openings provided in the screen and thus cause the formation a series of openings, holes or perforations in the sheet or plastic film. A method of obtaining the film with the tapered capillaries on one of its sides is shown in the patent of U. U., No. 3,054,148, issued September 18, 1962, to Zimmerli. In this patent, the heated film is supported by a perforated screen and a vacuum is applied to the lower side of the perforated screen. The holes are pulled in the film in the vacuum direction under the screen, thus forming tapered capillaries in the film. A variety of methods and apparatus, including particular types of drilling screens or rotary molding elements, have been developed over the years for particular drilling operations. Examples of them are the patents of E. U. A., Nos. 4,155,693, 4,252,516, 3,709,647, 4,151,240, 4,319,868 and 4,388,056. In the patent of E. U. A., No. 4, 155,693, the screen is comprised of a series of perforated metal strips, preferably welded together to form a cylinder. The patent of E. U. A., No. 4,252,516 provides a screen having a series of hexagonal depressions, with elliptical holes there centered. The patent of E. U. A., No. 3,709,647 provides a rotating roller that forms a vacuum, which has a circulating cooling medium therein. The patent of E. U. A., No. 4,151,240 provides a resource for cooling the film after it has been drilled and roughened. The patent of E. U. A., No. 4,319,868 indicates an apparatus for obtaining a thermoplastic film having raised protuberances with perforated tips. An embossing roll, particularly constructed, is described for effecting the desired film pattern. The patent of E. U. A., No. 4,388,056, discloses an apparatus for continuously forming a fibrous web placed in the air, having cylindrically curled side edges, of opposite phases, and a predetermined weight distribution with base. A drum, which is placed in the air, has an annular, honeycomb-like configuration frame including circumferentially extending ribs and transverse plates. A stationary, adjustable air flow modulating element is disposed adjacent the boundary, disposed radially inwardly, of an arcuate portion of an annular plenum chamber, circumferentially segmented which extends a plurality of segments thereof to adjust the pressure drop through particular areas of the surface of the drum that is placed in the air. Vacuum perforation of thin plastic films involves the extrusion of molten polymeric materials, such as polyethylene and other plastic polymers through a die. The hot melt strip of the film or plastic sheet exiting the die hits a rotating cylindrical screen, which is mounted on a drum or stationary vacuum roller. The vacuum roller has an axial groove and a set of seals, which extend longitudinally along the length of its inner surface, below the area where the plastic band strikes the screen or molding element. A vacuum from inside the screen is directed through the slit in the vacuum roller. The vacuum present within the slit forms or molds the film or sheet of plastic to the screen and pierces it through the holes in the screen. At the same time, an air flow is produced which cools the film. An important component of the vacuum processor equipment is the cylindrical screen. This molding element defines the aesthetic, tactile and mechanical properties of the film, as well as the geometrical pattern of the perforated film. In a preferred screen manufacturing technique, the desired screen pattern is plated with nickel in a cylindrical mandrel, specially prepared. A cylindrical, seamless, nickel screen, of any predetermined or desired pattern, may be produced. Other metals, such as copper, can also be used. However, the prior art screens produce a film with perforations that extend through the film substantially at a right angle to the surface of this film. Such perforations provide a direct line of sight and a direct path through the film. This feature of the prior art film is not convenient when this film is used in catamenial or incontinence applications, because the collected fluid remains visible. Therefore, there is a need for a perforated film having concealment characteristics, which reduces the visible presence of the collected fluids. It is also convenient to have a film that does not provide a direct path through the film for fluids. Such film can be used for protective clothing, because the fluids that make contact with the surface of the film will not have a direct path through the film. This feature greatly improves the protection quality of the clothing. EXPOSITION OF THE INVENTION The invention is directed to a thermoplastic film having a first surface and a second surface. This second surface is spaced from the first surface. A plurality of perforations extend through the film from the first surface to the second surface. The perforations form capillaries extending from the second surface. The capillaries are arranged at an angle of approximately 5 to 60 degrees with respect to a plane, which is perpendicular to the first surface. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic elevation view, showing the interrelation of the main pieces of equipment used to carry out the process. Figure 2 is an enlarged sectional view showing a segment of the forming surface as used in the process. Figure 3 is a schematic, amplified, sectional view of a perforated film of the prior art, having straight capillaries.
Figure 4 is a schematic, enlarged, sectional view of a perforated film of the prior art, having tapered capillaries. Figure 5 is a cross-sectional view of a screen forming a film, according to the present invention. Figure 6 is a cross-sectional view of a perforated film obtained with the use of the screen of Figure 5. Figure 7 is a cross-sectional view of a perforated film obtained with the use of the screen of Figure 11. Figure 8 is a cross-sectional view of a perforated film obtained with the use of the screen of Figure 12. Figure 9 is a cross-sectional view of a perforated film obtained with the use of the screen of Figure 10. Figure 10 is a cross-sectional view of a screen forming a film. Figure 11 is a cross-sectional view of a screen forming a film. Figure 12 is a cross-sectional view of a screen forming a film.
Figure 13 is a cross-sectional view of a fabric containing the perforated film of the present invention. Figure 14 is a gown using the fabric of Figure 13. Figure 16 is a face mask using the fabric of Figure 13. Figure 16 is a cross-sectional view of a cushion or curtain. Figure 17 is a cross-sectional view of a cushion or curtain. Figure 18 is a cross-sectional view of an ornamental fabric. Figure 19 shows a construction of a catamenial cushion using the film of the present invention. Figure 20 is a cross-sectional view, taken along line 20-20 in Figure 19. Figure 21 shows a diaper construction, using the film of the present invention. Figure 22 is a cross-sectional view along the line 21-21 in Figure 21. BEST MODE FOR CARRYING OUT THE INVENTION Referring to Figure 1, an apparatus for carrying out the method of the invention it includes a rotating cylindrical drum 10, supported at each end by a shaft 11, centrally arranged, supported by means of stationary axle supports 12. The cylindrical surface 13 of the drum roller 10 is highly perforated to allow air to pass therethrough. The molding element or screen 14 is mounted around the surface 13 of the drum 10 and adapted to rotate with the drum 10. The element 14 can be formed as an integral unit adapted to be slid on the drum 10 from one of its ends or it can be wound around the drum 10 and then fixed there in a suitable manner. In order to rotate the drum 10, a gear pulse can be employed, which is adapted to engage with the gear provided in the drum element itself, or a pulse pulley can be connected to the drum, by means of ferrules provided at its ends. As shown in Figure 1, a vacuum chamber 15 is used to create a pressure differential between the respective surfaces of the thermoplastic sheet, to cause the plasticized sheet to flow into the perforations provided in the molding element 14 and, therefore, drill the sheet. With reference to Figures 1 and 2, the vacuum chamber 15 is placed inside the drum 10, along the axis of the drum 10 and opens on the surface of the drum on a limited portion of its periphery, in contact with the portion of the surface 13 of the drum 10. Two plates 15A define the chamber. In order to provide an effective seal of the guide and trailing edges of the chamber 15, seals 16 are provided in plates 15A, to form a seal against the surface 13. The seals can be made of metal, HDPE, rubber or other adequate material. The plates 15A are stationary with respect to the rotary direction of the drum and are fixed rigidly to the shaft 11 or other suitable element, so that the chamber 15 remains in a fixed or stationary position in the drum 10. Thusthe chamber 15 is sealed at all points, except at the peripheral openings in the drum 10 and can be evacuated or reduced in pressure by the pumping equipment, connected to the chamber in any suitable manner. As can be seen in Figure 1, placed above and adjacent to the drum 10 is the extruder 21, which has a die 8, which is used to extrude a hot thermoplastic sheet 17 on the drum 10. In practice, it has been found that the polyolefin materials work particularly well as the thermoplastic material which is extruded onto the drum 10. As the sheet material 17 travels downwardly from the die 8, the sheet contacts the screen 14, which rotates clockwise with the drum 10 in Figures 1 and 2. The rotary screen 14 carries the sheet 17 over the vacuum slit 15, which causes the thermoplastic material to be stretched into the openings in the screen 14 and thus pierced. The sheet is cooled to change the hot thermoplastic material from its molten state to a solid state and to place the perforations in the film. The blade 17 continues to travel around clockwise, shown in Figure 1, on the drum 10 and continues to the rollers 19. From the roller 19, the solid sheet material 18 continues upwardly on the roller 21 to the roller 22 which treats the crown. This roller 22 which treats the crown is usually covered with a suitable dielectric material, such as epoxy, fluorinated polyethylene (TEFLON), chlorinated polyethylene (HYPALON) or polyester (MYLAR). However, the treatment of the net roller with a dielectric covered electrode can be used to treat the film. The electrode of the crown bar 23 is suspended parallel to the treatment roll at 1.5875 mm above the roller. The corona bar 23 is energized by a transformer and a corona treatment power source 24. The sheet continues to pass a tension roller 25 to a second tension roller 26 and onto a winding roller 27. It should be understood that the corona treatment operation is not required for all applications for the film and this part of the process may be omitted. Furthermore, it is not always necessary to wind the film on a winding roller 27 if the film is placed in an end-use application in an on-line process. It should be noted that other forming processes can be used to form perforated plastic films of the present invention. The process shown in the patent of E. U. A., No. 4,878,825, which uses a support for the forming screen in the area of the vacuum gap works particularly well in the formation of the perforated film of the present invention. The process shown in U.A. Patent No. 4,839,216, which uses a high pressure liquid stream to perforate a plastic film, can also be used with the present invention. The teachings of the patents of E. U. A., Nos. 4,878,825 and 4,839,216 are expressly incorporated herein by reference in this patent application, as alternative methods for forming the perforations of the present invention. Figures 3 and 4 show prior art types of perforated plastic films that have been produced in the apparatus shown in Figure 1. This film has straight stacks 3, as shown in Figure 3, or tapered capillaries 4, as is shown in Figure 4. In both of these films, the perforations are disposed substantially at an angle of 90 degrees to the surface of the film and provide a direct line of sight and a direct path through the film. A configuration of the screen 14 of the present invention, which is used to form the perforated plastic film, is shown in more detail in Figure 5. The screen 14 is a laminated structure comprised of a stack of individual sheets 31, 32, 33 , 34, 35, 36 and 37. The screen 14 has an external surface 39 which is arranged to be in contact with the thermoplastic sheet 17 and an inner surface 40 facing the vacuum chamber 15. The sheets contain a plurality of openings 41 that extend through the thickness of the individual sheets. The openings 41 all preferably have the same geometric configurationIn a substantial manner, however, it should be understood that the configurations of the openings may be different. The sheets are usually stainless steel, photo-etched metallic material, where the gravure has formed openings 41 in the individual sheets. The leaves generally have a thickness of about 25.4 to 127 microns. In practice, it has been found that leaves having a thickness of about 50.8 microns work particularly well. Usually, about 2 to 20 sheets are used to form the screen 14. The preferred range for the number of sheets forming a screen 14 is approximately 4 to 10 sheets. The effective diameter of the openings 41 in the leaves is from 50.8 to 2540 microns. In practice, it has been found that a range of about 177.8 to 1524 microns for the effective diameter of the openings 41 works particularly well. The sheets of the laminate are joined together at contact points, while the laminate is subjected to heat and pressure. The resulting structure of the laminate is then laminated into a tubular configuration and its free edges are joined together to form a tubular structure. As shown in Figure 5, the openings 41 in the laminate structure are not aligned concentrically. Instead, the openings 41 are circumferentially displaced in the same direction to form a passageway 45 through the laminate structure, which is arranged at an angle. The openings 41 shown in Figure 5 all have the same diameter and each opening has moved about 1 to 50% of the diameter of the openings from the opening in the adjacent sheet, with a preferred range of 5 to 25% of the diameter of the openings. In practice, it has been found that a displacement of about 10% of the diameter of the openings works particularly well. This results in a passage 45 which is arranged at an angle of approximately 6 to 60 degrees with respect to the plane or line 47 extending perpendicular to the external surface 39 of the screen 14. This angle is generally shown as an angle A in Figure 5. The openings 41 in the sheets are generally circular in configuration and the passageway 45 formed through the lamination screen 14 is generally cylindrical. However, it should be understood that the configurations of the openings may vary and that oval, ellipsoidal and other configurations may be used, and multiple-sided shapes, such as a rectangle, square, hexagon or pentagon may be used for the openings. As shown in Figure 10, the screen 14 'has openings 41' which become progressively smaller in each adjacent sheet of the laminate. In this screen structure, the passages 45 'formed will converge as the passages advance through the screen 14'. In this particular structure, each opening 41 'is displaced by a selected percentage of its diameter from the openings in adjacent sheets. This results in a passage 45 'that converges, continuously and uniformly, as the passage advances through the screen 14'.
The screen 14", shown in Figure 11, has openings 41" that become progressively smaller as the openings shown in Figure 10. However, in Figure 11, the openings 41"move in the screen 14" as passage 45"converges in a direction advancing through screen 14". As shown in Figure 12, the screen 14 '• * defines a passage 45''1, which has a composite curve for the passage. In this embodiment, a portion of the sheets forming the screen 14 '' 'is displaced in one direction to form a first portion 51 of the passage 45'11 and a plurality of sheets move in the opposite direction to form a second portion 53. for the passage 45 ll1. Normally, all openings 41 '' 'will be of the same diameter and will be displaced by an equal distance in each layer of the screen 14, 1,. However, it should be noted that the openings 41,,, may vary in size and the amount of displacement may vary to form a converging passage 45 ,,, -. The first portion 51 of the passage 45 '"is arranged at an angle A which is approximately 5 to 60 degrees with respect to a line or plane 47', which extends perpendicular to the external surface 39" 'of the screen 14 The second portion 53 is arranged at an angle B that is approximately 5 to 60 degrees with respect to the plane or line 47. Figure 6 shows a cross section of a film 54 that has been formed using the screen shown in FIG. Figure 5. The film 54 has a first surface 59 and a second surface 64. The first and second surfaces of the film are usually placed in a substantially parallel relationship.This film has a plurality of perforations 52 that form capillaries 56 in the film. The capillaries 55 have a substantially uniform diameter and move at an angle A of approximately 5 to 60 degrees with respect to the plane 47, which is perpendicular to the first surface 59 of the film. The capillaries 55 are of substantially cylindrical configuration, have a side wall 62, define a passage 65, have a first opening 58 in the surface 59 of the film 54 and a second opening 60 in the end 57 of the capillary 55, which is spaced from the first surface 59 of the film 54. The ends 57 of the capillaries 55 are usually spaced from the surface 59 of the film 54 by a distance of about 127 to 1270 microns, with a spacing of 177.8 to 635 microns with the preferred opening 58 and opening 60 both have a center point or geometric center and the center point of opening 58 is displaced from the center point of opening 60. The center point of opening 60 is offset from the center point of opening 58 by a distance that is around 5 to 200% of the diameter of the opening 60, with the preferred range being approximately 75 to 125% of the diameter of the openings 60. As is can be seen in Figure 6, the stacks 55 have a plurality of steps or ridges 56, which are produced by the displaced sheets of the screen 14. These ridges 56 on the film 54 are substantially rounded instead of having sharp corners formed by the edges. displaced sheets forming the screen 14. Figure 9 shows the cross section of a film 54 'that has been formed using the screen shown in Figure 10. This film 54' is substantially similar to the film shown in Figure 6, except that the side wall 52 ', each capillary 55' and the passage 65 'converge as they extend from the first surface 59' of the film. Figure 7 shows a cross section of a film 54"that has been produced using the screen of Figure 11. In this film, the side wall 62" of the capillaries 55"and the passage 65" converge as it moves away from the surface of the film and, in particular, converge on one side in one direction. Figure 8 shows a cross section of a section of the film 54 • • •, produced using the screen shown in Figure 12. In this figure, the capillaries 55 * '* and the passage 65' '' have a first portion 61 that is disposed at an angle A with respect to a plane 47, which is arranged perpendicular to the first surface 59"of the film and a second portion 63, which is disposed at an angle B and both angles are approximately 5 to 60 degrees with respect to plane 47. In Figure 8, the capillary 55 '' * It generally converges as it advances from the first surface 59 '' 'of the film 54' '' However, it should be understood that the capillaries 55 '' 'may have non-convergent walls. they have an angle that acts to block a direct line of sight through the openings, which is perpendicular to the surface of the film, therefore, the films will have hiding characteristics, so that the fluids passing through the movie to a structure Absorbent ura will not be as visible to the user as when the capillaries are perpendicular to the first surface 59 of the film. This is particularly important for catamenial or incontinence applications. The degree of concealment produced by the film will be directly proportional to the angle of the capillaries in the film, its length and the degree to which the capillaries converge in configuration. Such films may also be useful in preventing undesired direct flow of fluid through the film. Since the capillaries are arranged at an angle, the fluid that hits the surface of the film will not have a direct path through the film. Instead, the fluid will have to change direction to pass through the capillaries. Such a film can be used to protect clothing when fluids can come into direct contact with the surface of protective clothing. The film of the present invention reduces the tendency of the fluid to splash directly through the stacks and greatly improves the protective capacity of the clothing. Figure 13 shows a layered fabric material using the film of the present invention. The fabric material 70 in layers has a lightweight, breathable outer layer 73. This outer layer 73 is usually a paper covering material that is very light in weight and also highly breathable. Next is a layer of non-woven material 75, which is breathable, but supplies the passage of fluids through this layer. In particular, the non-woven material provides good resistance to the flow of liquids that come into contact with the non-woven material. A molten polypropylene, polyethylene or polyester can be used for the non-woven layer, since these materials have acceptable levels of fluid resistance. The next layer in the fabric 70 is a thermoplastic film 79, which has a plurality of perforations 81 and the capillaries 83 form perforations and they are arranged at an angle of approximately 5 to 60 degrees with respect to a plane that is perpendicular to the surface 85 of the movie. The thermoplastic film 79 is positioned so that the stacks 83 extend toward and are in contact with the nonwoven material. The capillaries 83, formed by the perforations 81, allow the film 70 to be breathable, while resisting the direct flow of the liquid through the film. Although the film 79 has been shown to be substantially similar to the film 54 shown in Figure 6, it should be understood that the film similar to the films shown in Figures 7, 8 and 9 can also be used for the film 79 in the 70 layer fabric material. The next layer in the fabric 70 is a second layer of nonwoven material 87, which is placed adjacent the surface 85 of the film 79. The second layer of nonwoven material 87 is intended to be a layer that comes into contact with the skin. of the user of the cloth material 70. If the cloth material does not attempt to come into contact with the user's skin, the second layer of the nonwoven material 87 can be omitted. The purpose of the fabric material 70 is to provide a breathable structure having good resistance to the penetration of fluids and more particularly liquids. The fabric 70 is intended to be used in applications where fluids are splashed or sprayed on the material and this material provides resistance to the direct passage through the fluid. This fabric can be used in the medical field, the hazardous waste field and other areas where people are interested in protecting themselves from fluids that are spilled or sprayed. Figure 14 shows a protective gown 89 and Figure 15 shows a protective face mask 91, which can be obtained by using the fabric material 70 in layers. For the protective gown 89, the second layer of non-woven material 87 can be omitted if the gown is to be worn on the garment, so that the inner surface of this gown will not come into contact with the wearer's skin. For both the protective gown 89 and the face mask 91, fluids that are spilled or sprayed will contact the outer layer 73 of the fabric. The fluid will pass through the non-woven material 75, which provides resistance to fluid penetration. The fluid will then come into contact with the thermoplastic film 79 having capillaries 83 at an angle. When the fluid makes contact with the thermoplastic film 79, there is no direct path through the film and the fluid velocity is significantly reduced. The structure of the layered fabric 70 is intended to prevent direct passage of fluids and provides a much higher level of protection than the breathable materials that are currently available. Figure 16 shows the use of the thermoplastic film of the present invention in an absorbent cushion or mat 88. In the structure, the film 79 is placed on a layer of absorbent material 93. This film 79 is arranged so that the capillaries 83 which are formed by the perforations 81 are in contact with the absorbent material 93. With the structure, the capillaries 83 will act to absorb the fluid that is on the surface 85 of the thermoplastic film 79 to the absorbent material 93. The angle for the capillaries 83 prevent a direct line of sight along a line that is perpendicular to the surface of the film, within the absorbent material 83, so that the fluids that are contained in the absorbent material 83 are not easily visible when viewing the surface 85 of film 79. Figure 17 shows another embodiment of a cushion or mat 90 that can be obtained using the film of the present invention. The film 79 is placed with the surface 85 in contact with a layer of the absorbent material 93. The film 79 is positioned so that the stacks 83 formed by the perforations 81, extend in a direction away from the absorbent material 93. With the capillaries 83 extending away from absorbent material 93, there is more resistance to impact of a liquid that is under pressure, such as a spilled or spilled liquid. Figure 18 shows the use of the thermoplastic film 79 as an ornamental fabric 94. In this application, the film is placed with the capillaries 83 extending towards the floor 95, in which the film is to be placed. The perforations 81 and the capillaries 83 allow moisture, such as rain, to pass through the film to the ground. However, the angled capillaries 83 effectively eliminate or minimize the amount of light that can pass through the film 79. This prevents the growth of weeds and other unwanted growth in areas where the film is placed. However, since rain can pass through the film, there is no difficulty with the disposal or accumulation of rainwater. In applications where additional strength is required, a non-woven material 97 can be laminated to the surface 85 of the film 79 to provide additional strength. It should also be understood that the nonwoven material 97 may also be laminated to the opposite side of the film 79 to provide additional strength to the ornamental fabric 94. Figures 19 and 20 show a catamenial cushion or for female hygiene, which can be constructed using the film of the present invention. The cushion 105 has a layer of a perforated thermoplastic film 79, which is placed on an absorbent core 107. The film 79 is positioned so that the ends of the stacks 83, which extend from the film, are in contact with the core. absorbent 107. This absorbent core may include one or more layers of a non-woven material 109, and a highly absorbent wadding or gel 111 material. A non-permeable thermoplastic film 113 is placed on the side of the absorbent core 107, which is opposite the film 79. Figures 21 and 22 show a diaper product 115 that can be constructed with the use of the film herein. invention. The diaper 115 has a layer of a perforated thermoplastic film 79, which is placed on an absorbent core 117. The film 79 is positioned so that the ends of the capillaries 83, which extend from the film are in contact with the absorbent core. 117. This absorbent core may include one or more layers of a non-woven material 119 and a highly absorbent wadding or gel material 121. A non-permeable thermoplastic film 123 is placed on the side of the absorbent core 117 that is opposite the film 79. It should be noted that the film layer 79, shown in Figures 19 to 22, will provide concealment of the fluid that is retained in the film. the absorbent core material, as previously discussed. It should be understood that a film similar to the films shown in Figures 7, 8 and 9 may also be used as the film 79 in the applications shown in Figures 16 to 22. The above description of the invention is provided for of explanation and various modifications and substitutions, in addition to those mentioned, may be made without departing from the scope of the following claims.