METHODS OF MAKING BRUSHES, AND BRUSHES THUS MADE

Abstract: Method of making brushes for cleaning preferably bacteria-polluted surfaces, particularly the skin, gums or teeth, in which the body (1) of the brush shall be provided with a great many bristles (2) designed to collectively form a uniformly distributed bristle covering on the brush body (1) or parts thereof. To apply the bristles (2) to the brush body (1) in a very rapid and solid manner even though the body and the brush are very small, a surface (3) of polyamide material of the brush body (1) is supplied with a water-soluble organic acid (8) to dissolve the brush body surface (3) of polyamide material, whereupon bristles (2) of preferably polyamide material are attracted to the brush body (1) by electrostatic attraction so that those end portions (17) of each bristle which come in contact with the dissolved surface (3) of the brush body (1) are dissolved and caused to fuse with said surface to form a brush in which the body (1) and all bristles (2) are integrated into a unit. A brush product particularly suitable for dental care, which has been produced by this method, has a body (1) comprising an end portion (1a) devoid bristles to permit being grasped during brushing without coming in contact with the bristle-carrying parts of the body (1).

Description: Method of making brushes, and brushes thus made. This invention relates to a method of making brushes for cleaning preferably bacteria-polluted surfaces, particularly the skin, gums or teeth, in which the body of the brush shall be provided with a great many bristles designed to collectively form a uniformly distributed bristle covering on the brush body or parts thereof. The invention also relates to brushes made by the novel method. In many cases, it has proved very difficult to apply the bristles of the brush to the brush body in a rational and be- sides durable manner. These problems are particularly serious where small brushes are concerned, which are designed for clea¬ ning the skin, gums or teeth, because relatively small brush bodies and bristles are required for such brushes. Attempts to secure small bristles by gluing to small brush bodies have not been very successful. The present invention aims at eliminating this problem and providing a novel method -that permits applying the brist¬ les in a very rapid and solid manner to the brush body even though the body and the bristles are very small. This aim is achieved by the invention substantially in that the novel inventive method comprises the features defined by appended claim 1. Furthermore, the invention has the purpose of providing an advantageous brush made by the method according to the inve tion, this brush comprising the features defined in the charac terizing clause of appended claim 10. The invention is elucidated more in detail below with reference to the acc mpaning drawings in which: Figure 1 diagrammatically illustrates the method of the invention; Figure 2 illustrates a finished brush made by the method of the invention; Figure 3 illustrates an enlarged section of the brush shown in Figure 2; Figure 4 illustrates a section on line IV-IV in Figure 2; Figure 5 illustrates .a brush of alternative design; and Figure 6 illustrates a section on line VI-VI in Figure 5. The method of making a brush, which is illustrated in Figure 1, serves to make a relatively small brush for brushing the gums and teeth. The brush comprises a body 1 and a great number of bristles 2. The body 1 to at least the major part consists of polyamide material or has a surface 3 of poly¬ amide material, and bristles 2 of the brush also consist of polyamide material. In this instance, the body 1 suitably is 30-70 mm, preferably about 50 mm, long and at its widest part about 6 mm wide and at its thickest part about 2 mm thick. The body 1 has an elongated and tapering apex 4 which suitably constitutes the major part of the body 1. The brist¬ les 2 of the brush are of a length of approximately 0,5-2 mm (the bristles may be of equal length or of different lengths) and the thickness of the bristles 2 is essentially less than the length thereof. These small bristles 2 are designed to be applied to the relatively small brush body 1 in a rational and extremely solid manner. Figure 1 diagrammatically illustrates how the method of the invention is carried out. If necessary, the brush body 1 at station 5 is dipped into water 6 in its entire length for moistening of the entire body 1, thus making it possible for the surface 3 thereof to become current-conductible. The body 1 is then moved to station 7 where it is dipped into a water- -soluble organic acid 8, preferably formic acid. At station 7, only those parts of the body 1, that is its apex 4, to which bristles shall be applied, are submerged. The water-soluble organic acid causes the surface 3 of the brush body 1 to be dissolved. At the following station 9 the body 1 with the surface 3 in dissolved state is held over a container 10 with an electrode 11 at its bottom, a larger number of bristles 2 and a grid 12 at its top, having such a mesh width that the bristles 2 can pass therethrough. The bristles 2 consist of preferably the same polyamide material as the surface 3 of the brush body 1 (or possibly as the enti- re brush body) , and the bristles lie in a fully loose state in the container 10. The electrode 11 is connected to a current source 13 and the brush body 1 is disposed above the container 10 spaced a suitable distance from the electrode 11. With the body 1 in this position, the current-conductible surface 3 thereof is earthed via a holder, which keeps the body in position, and an earth connection 14 extending from said holder. On supply of current from the current source 13 to the electrode 11 ther is generated an electric field between the electrode 11 and the current-conductible surface 3 of the brush body 1, whereby the bristles 2 are attracted to the body 1 simultaneously as said bristles 2 repel each other, being thus uniformly distributed over the surface 3 'of the brush body 1. By reason of this elec static attraction of the bristles 2 they will orientate them- selves so as to protrude straight outward from the brush body making a substantially right angle with those parts of the brush body surface 3 to which they adhere.. As the end portions 17 of the bristles 2 contact the dis¬ solved surface 3 of the brush body 1, said end portions 17 are dissolved by the action of the water-soluble organic acid 8 which is present on the dissolved surface 3 of the brush body. As a result, the dissolved brush body surface 3 and the end portions 17 of the bristles 2 are fused together and when the fused parts 3, 17 have solidified the bristles 2 will be fully integrated with the brush body 1, thus forming inseperable parts. Of special advantage is that also the narrowest portions of the brush body apex 4 present fully integrated bristles 2, that if the bristles 2 are heavily anchored also to narrow parts of the brush body 1. In addition to the finished brush product obtaining a solidly adhering bristle covering, it can also be given a bacteria-inhibiting effect because it is made of polyamide material and/or because it has been treated with a water-solub organic acid of bacteria-inhibiting action. The effect of the bristle application can be varied by varying the time and/or the effect of the electric charge of the bristles 2. Besides, during the bristle application proce dure the distance of the brush body 1 to the bristles may be variable and/or the length of the attraction moment may be variable. As only the surface 3 of the lower parts 4 (apex 4) of th brush body 1 has been exposed to water-soluble organic acid 8 while the surface of the upper parts la (a handle portion la) of the brush body 1 has not been exposed to said acid 8, only the surface 3 of the lower parts 4 and not that of the upper parts la of the brush body is fused, which implies that the bristles 2 only adhere to the lower parts 4 and not to the upper part la of the brush body. As a result, there is formed in a simple manner a handle portion la devoid of bristles on the brush body 1. The brush body 1 having integrated bristles 2 thereon may be moved to a station 15 in which the finished brush products are washed in water 16 for removal of excess acid possibly remaining on the products. At the same time, loose bristles 2 may be removed from the products by flushing, shaking, rubbing, blowing or otherwise whereafter the products are ready for packaging and deliviery. The invention is not restricted to the process described or the product described, but can be varied within the spirit and scope of the appended claims. Thus, water-soluble organic acids other than formic acid may be employed. The number and type of processing stations may vary, for instance the moiste¬ ning of the brush body 1 may take place by spraying of the body instead of submerging it in water or other suitable liquid at station 5. A particular moistening operation may be dispensed with if the brush body 1 before the submerging thereof in orga¬ nic acid has been stored or transported in so moist an environ¬ ment that it has absorbed a sufficient quantity of moisture to make the surface of the brush body current-conducible. The brush product described in the foregoing and illustra¬ ted in the drawings is small and specifically suited for dental care, and even though the dimensions indicated are specifically suited for a small brush product for such purposes, the dimen- sions indicated may be exceeded without making the product unusable for its purpose. The dimensions of the brush product may still vary essentially beyond those mentioned in the specification in case the brush product is to be used for other purposes, i.e. for care of the skin, for which purpose there are required brush products or larger dimensions than those mentioned. In the brush embodiment illustrated in Figures 5 and 6 the brush body 1 consists of an elongated flexible thread of poly¬ amide material and this thread is of substantially circular cross sectional area and intended for use as dental floss. When submerged in the organic acid 8 at station 7, the floss • end portions lb, lc are not dipped into the acid 8 but only the floss segment intermediate the end portions lb, lc. This implies that the end portions lb, lc of the dental floss are not coated with bristles at station 9 but only the intermediate parts thereof. As a result, the dentai floss will present a first end portion lb or lc by which it can be grasped during the cleaning operation, and a second end portion lc or lb which is adapted to 'serve as a dental floss apex for facili¬ tating the penetration of the dental floss between the teeth. The body 1 in this case is of such rigidity that the dental flo substantially retains its shape at the introduction of the apex thereof between the teeth, while the other end portion devoid of bristles is grasped as a handle portion. The body 1, how¬ ever, is not so rigid that it cannot be easily bent during the cleaning operation. By reason of the bristle covering, the bristle-coated part of the dental floss will be somewhat more rigid than the floss end portions lb, lc.

Claims: Claims. 1. A method of making brushes for cleaning preferably bacteria -polluted surfaces, particularly the skin, gums or teeth, inwhich the body (1) of the brush shall be provided with a great many bristles (2) designed to collectively form a uniformly distributed bristle covering on the brush body (1) or parts thereof, c h a r a c t e r i z e d i n that a surface (3) of polyamide material of the brush body (1) is supplied with a water-soluble organic acid (8) to dissolve the brush body surface (3) of polyamide material, whereupon bristles (2)of preferably the same polyamide material as that of the brush body surface (3) areattracted to the brush body (1) by electrostatic attraction so that those end portions (17) of each bristle which come in contact with the dissolved sur¬ face (3) of the brush body (1) are dissolved and caused to fuse with said surface to form a brush in which the body (1) and all bristles (2) are integrated into a unit. 2. A method as claimed in claim 1, c h a r a c t e r i z i n that bristles (2) are attracted by electrostatic attraction to cause them to orientate in such a manner as to protrude -substantially straight outward from the brush body (1) and to be spaced substantially the same distances apart. 3. A method as claimed in claim l or 2, c h a r a c t e ¬ r i z e d i n that the bristles (2) to be applied to the brush body (1) are electrically charged and attracted to the brush body (1) by imparting, to the dissolved surface (3) of the brush body (1) electrically conducting properities and an electric polarity opposite to the electric charge of the bristles (2) . 4. A method as claimed in any one of the preceding claims, c h a r a c t e r i z e d i n that the time for and/or the effect of the electric charge of the bristles (2) to bring about their attraction to the brush body (1) is variable and/o that the distance of the brush body (1) to the bristles (2) during the attraction moment and/or the length of the attrac- tion moment is variable. 5. A method as claimed in any one of the preceding claims c h a r a c t e r i z e d i n that the brush body (1) is supplied with a water-soluble organic acid (8) such as formic aci / _ 6. A method as claimed in any one of the preceding claims, when only parts (4) of the brush body (1) shall be provided with bristles (2) , c h a r a c t e r i z e d i n that the entire brush body (1) is moistened to make the surface (3) thereof electrically conductible, whereupon only those parts (4) which shall be provided with bristles (2) are supplied with a water-soluble organic acid (8) . 7. A method as claimed in any one of the preceding claims, c h a r a c t e r i z e d i n that excess water- -soluble organic acid (8) is caused to evaporate after the bristles (2) on the brush body (1) have fused with the sur¬ face (3) of the brush body (1) . 8. A brush made in accordance with claim 1 and desig¬ ned for cleaning bacteria-polluted surfaces, particularly the skin, gums or teeth, in which a body (1) having a sur¬ face (3) of polyamide material presents bristles (2) of pre¬ ferably the same polyamide material, c h a r a c t e ¬ r i z e d i n that the brush body (1) has an end portion (la) devoid of bristles to permit being grasped without makin contact with the bristle-carrying parts of the brush body (1) 9. A brush as claimed in claim 8, c h a r a c t e ¬ r i z e d i n that the brush body (1) has two end portions (lb, lc) devoid of bristles, and consists of elongated flexibl dental floss of such rigidity that it is capable of substan- tially retaining its shape when one end portion (Iborlc) devo of bristles and serving as a dental floss apex is introduced between the teeth while the dental floss is grasped by its other end portion (lc or lb) devoid of bristles and serving as a handle portion, the rigidity of the dental floss, howeve being insufficient to prevent easy bending to the floss durin the cleaning operation. 10. A brush as claimed in claim 8, c h a r a c t e ¬ r i z e d i n that the brush body (1) is 30-70 mm, pre¬ ferably about 50 mm, long, at its widest part about 6mm wide, and at its thickest part about 2 m thick, and has an elongated tapering apex (4) constituting the major part of the brush body (1) , that each bristle (2) is of a length of between 0,5 and 2 mm and of a thickness essentially smaller than said length, and that the bristles (2) cover the apex (4 of the brush bod (1) leavin at least the ma or art of the other portions of the brush body (l) free so that there is for¬ med an end portion (la) devoid of bristles.

Inventors: STERN LEIF EINAR, STERN, LEIF, EINAR
Applicants: STERN LEIF EINAR, STERN, LEIF, EINAR
Application year: 1985
Main classification: A46B3
IPC codes: A46B5, A46B9, A46D1, A46D3, A61C15