DE1118650B - Safety razor blade and method for making the same - Google Patents

Description

The invention is concerned with the improvement of single- and double-edged safety blades with the aim of reducing the excessive tensile stress on the stubble attacked by the knife, in order to avoid the skin irritation that occurs particularly when dry shaving. This task So far, it has been done by pretreating the whiskers with emollient materials or by covering them tried to solve the blade cutting edge with some materials.

The invention is based on this second approach and creates using one in the Technique known coating material a cutting edge coating that adheres intimately to the blade With a layered structure that enables particularly comfortable and smooth shaving. This coating consists of a suitably hardened, silicon-containing organopolymer, which the manufacturers for its "adhesive" and water-repellent properties for a long time as a dry, non-oily coating material have suggested for some inorganic and organic bases. It was also as a coating material for metal base layers, including for technical knives and cutting edges, proposed where it prevents stickier organic material from adhering and facilitated one Cleaning made possible. A more or less was used as the curing condition Minutes during heating to 105 to 150 ° C mentioned.

The housewives were also advised to keep pots, pans and other kitchen tools, including knives, forks, spatulas, disc turner, etc., thereby preventing heat discoloration and burning to protect from food ingredients that one does not use this equipment with a solution coated with thermosetting silicone. There are also saucepans and similar metallic cooking utensils inside and outside with a coating of a hardened, non-viscous, high molecular weight, alkylated Provided siloxy compound, in particular to save baking and frying fat.

In medicine, in addition to many other uses, silicone oils are used as sterilizing fluids used for dental handpieces and surgical instruments in place of water, because they do not have a corrosive effect, on the contrary, they have a protective effect on these metal parts and protect against dulling of sharp instruments.

The invention now consists in the use of a coating of a silicon-containing organo-safety razor blade
and methods of making them

Applicant:

The Gillette Company,
Boston, Mass. (V. St. A.)

Representative: Dr. phil. G. Henkel,

Berlin-Schmargendorf, Auguste-Viktoria-Str. 63,

and Dr. rer. nat. W.-D. Henkel, Munich 9,

Patent attorneys

Claimed priority:

V. St. v. America November 25, 1958 (No. 776 203)
and June 22, 1959 (No. 821 623)

Leon Edmund Granahan, Hingham, Mass.,

Meyer Joseph Shnitzler, Brookline, Mass.,

and Edward Morrill Tuckerman, Cohasset, Mass.

(V. St. A.),
have been named as inventors

polymer on metallic cutting edges to improve the shaving properties of safety razor blades through one applied to their cutting edges and through partial or complete crosslinking of the polymeric material on the blade adheres better to the side surfaces of the cutting edges Coating. Thus the invention does not consist in the mere application of a silicone coating to one A cutting tool of a special kind, like a razor blade, but also teaches you how one in the present, special application in which, in contrast to all common types of Use of a cutting blade to cut the object from a one-sided clamped, i.e. flexibly evasive, thread-like body, namely a hair, there is the special problem characteristic of this a reduction in the tension exerted on the hair through a special internal structure the coating adhering to the blade can loosen. This was recognized as crucial according to the invention Layer structure is a gel-like, with that used in the description and claims Expression gel a structure of a networked

109 747/63

Polymer is referred to, which is an insoluble, infusible, coherent, three-dimensional Has network with therein contained liquid material of lower molecular weight. This A structure must be distinguished from a hard, glass-like structure. The shape of the material used is a stable, soft gel that adheres to the steel surface underneath. The term »soft Gel «is intended to express that the gel, in contrast to hard, glass-like materials, is inside or has a low shear resistance on the surface or in both places. The expression On the other hand, "stable" means that a blade cutting edge covered with the soft gel material also then has even better shaving properties if it is used for at least 3 months under normal market conditions has been stored. The gel should preferably be mixed with water and the usual shaving soaps or creams are insoluble and are said to be non-toxic.

In the context of the invention it has now been found that a steel blade, on the cutting edge of which is a to the underlying steel adhering layer of the gel material defined above, both easier shaving as well as a noticeable reduction in tension, namely a reduction in the Cutting or severing the whiskers required force, reveals the importance of the hitherto usual, complete whisker softening and thereby the duration of the beard softening step to be abbreviated. Under mechanically controlled conditions from - not on the face - Investigations into the cutting ability of coated blades showed that the The force required to cut water-softened hair is greatly reduced. These Reduction of tension and easier shaving can be achieved over several consecutive shaves with the the same, adhesive-coated blade edge continues to exist, although it does not last indefinitely hold on for a long time.

Although the working theory of the invention may not be fully understood and the following explanation is not considered to be binding, it is believed that the reduced drag during shaving is primarily due to shearing of the organosilicon-containing polymer during the cutting process. The total force required for a haircut consists of at least two components, one of which consists of the force required to pierce the outermost cutting edge through the hair and the other of the force required to overcome the jamming and adhesion of the partially severed hair the flanks of the wedge-shaped cutting edge caused friction is required. This latter force is likely to be the larger component of the total force required to sever the hair. For example, in the case of an ax cutting into the side of a tree, the clamping friction on the flanks of the cutting edge will be so great that the ax will stop before going deep into the Wood penetrates. Heretofore, much effort to improve shaving has been directed to perfecting the cutting edge and softening the hair to be cut. Such a composition is preferably obtained by crosslinking a selected organosilicon-containing polymer on the cutting edge itself, which polymer has a plurality of siloxy groups, in which, for example, silicon is bonded via oxygen to silicon or other elements in the polymer structure. This is the case, for example, with an organosiloxane, with a silyl polyester or with a modified organosiloxane in which a small part of the silicon atoms has been replaced by atoms of another material. For example, one of every 20 silicon atoms can be replaced by a tin atom. The cross-linking creates a structure in which some of the silicon atoms in the polymer chains are cross-linked and the polymer adheres to the steel blade underneath. The crosslinking is preferably carried out according to the so-called air crosslinking process, ie by heating in hot air, although longer exposure, for example with rays of radioactive material at room temperature, is also useful. It is not important that the networking be done entirely locally; the organosilicon-containing polymer can rather be partially crosslinked in advance and then completely crosslinked on the blade itself.

The gel material layer can extend over the entire wedge surfaces from the outermost edge away extend inwards or even beyond these areas or only the area of the last, cover the facet immediately adjacent to the outermost edge. Experience has shown that they give in some cases even incredibly thin layers, on the order of 0.03μ thick or less, which are so thin that their presence can only be detected with considerable difficulty, still recognizable beneficial effect during the first face shave with the blade. For the thickness of the adhesive coating there is no exact upper limit, and experience has shown that in some cases there are still Thicknesses many times greater than the aforementioned order of magnitude give useful results. The thickness is usually not uniform over the entire layer surface and needs to be not to be either, but rather diminishes towards the edges.

Coated razor blades according to the invention, which under the interference microscope magnified several hundred times, perpendicular illumination with white light and perpendicular position of the test surface to the optical axis of the microscope a pattern of spectral Show interference fringes. In certain blades of the invention having excellent shaving properties the total number of seams made in that from the outermost cutting edge was 0.05 mm inwardly extending area were observed, an average of twelve. That means that the Thickness of the coating, starting from the outermost edge, gradually increasing to an average thickness of 2.5 μ increased at a distance of 0.05 mm. To achieve these values, a refractive index of 1.5 and a half-wavelength for white light of 0.3 μ is used.

Experience has shown that when using monochromatic lighting, for example the yellow sodium or the green mercury line, depending on the thickness and contour of the film, far more seams watch. Shaving soaps and creams have little effect on reducing the risk of hair loss Hair parting requires total force, unless it is applied until it does

Soften the beard by wetting it. The invention obviously reduces this force in a more novel way Way, by inserting a material between the blade and the hair, which during the entire shaving process firmly adhered to the flanks of the cutting edge, but either inside or on the contact surface with the hair easily shears off. This shearing can result from pressing out be accompanied by liquid from the material of the adhesive coating.

In the sense of the working theory described, certain advantages exist for achieving the advantages mentioned Conditions. The adhesion or bonding of the adhesive coating material to that of the blade suddenly May have breaks. A blade provided with such a coating is referred to in FIG Shaving properties no better and possibly even worse than an untreated blade.

Blades with a very thin initial coating on the order of 1 to 2 microns thick from the same material show largely the same behavior with increasing degree of crosslinking, only has then, as can be seen from the absence of interference fringes, that after removal of the overlying fringes Liquid or the very soft gel remaining directly on the metal Thickness less than 0.2μ.

Very thick covers made of the same material,

are crosslinked beyond the above point in which the top coat layer at first use of the blade is repelled.

The useful range of crosslinking is wide, but not unlimited, and depends on the one used special organosilicon-containing polymer. In the case of methyl hydrogen siloxane, this is the case Area fairly wide, but by no means unlimited.

The facets adjacent to the edge must be so large that the ΙΟ-μ coating, which is much greater than the thickness of the film during shaving, should not be removed if the facet surface adjacent to the cutting edge is not removed. Cohesion within the
Material of the adhesive coating or its adhesion to the
Hair must be smaller than its adhesion or bond 20
be on the metal surface so that it can be sheared from the metal without complete removal
can. The one required for such a shear
The force, on the other hand, must be so small that the total force required to cut hair with a treated blade that is both too weak and too strong is less than that of an unsatisfactory coating, which must be the shaving properties of the treated blade. Don't improve the sound. The organo-material coating of the adhesive coating must also have so much silicon-containing polymer in the event of insufficient or compressive force that there is no overall insufficient crosslinking, little or no adhesive contact between hair and metal. These 30 on the steel blade surface. Probably requirements are met by a treated blade based on this inefficiency and lead to a strong reduction in the poorly crosslinked coating due to the lack of pulling on the hair and the resulting adequate adhesion to the steel surface, resulting in shaving inconvenience. Since the number of shaves is limited to a few shaves due to the coating already in the first few shaving processes in which the mentioned material effect 35 strokes of a shaving process are retained by the blade. If the crosslinking is too extensive, a certain material appears to occur during use - on the other hand, the polymer transition adheres firmly to abrasion. the steel blade surface, but does not shear in its

The extent of the coating shear depends on the interior of the surface in contact with the the networking status. If a relatively thick 40 hair off easily enough. Probably the Coating, namely from 10 μ in 0.125 to 0.15 mm Poor performance of one understood too much from the outermost edge, made of methyl-water-reticulated coating on this high shear resistance. substance-siloxane, as used in Example 1 later, there is therefore between undercrosslinking and overlinking is, is crosslinked for a short time, usually remains an area of useful crosslinking conditions, the the uppermost coating layer, liquid, becomes the one that has never been achieved before, on the first 45 of the blade Blade use removes and leaves on giving shaving properties.

Organosiloxanes that can be used include the organosilicon-containing polymers. they consist of chemical compounds with a network of 50 alternating silicon and oxygen atoms, in which most of the silicon atoms are attached organic through carbon-silicon bonds Carry substituents. By their nature they are polymeric substances in the form of linear chains or the underlying, less than 2 μ thick layer in the 55 cyclic polymers.

from the outermost edge of the blade inwards. While the nature of the various substitute

extending about 0.05 to 0.125 mm wide zone generating groups both chemically and physically sheared will. The remaining, firmly rooted in the sical properties of the organosiloxanes A thin layer of metal adhering to it flows, the chain length and the number of cross-linking processes occurring during a larger number of shaving or crosslinking acts effective. fertilize primarily on the physical properties

Metal surface a layer of polymeric material less than 1 μ thick! Gel that is at least one more further shave creates the achieved substantial improvement in the shaving characteristics.

If the same type of coating is crosslinked for a little longer, the entire coating mass is converted into a Gel around, but still so soft and weak that the uppermost part of the layer of the first shave

The 10 μ thick coating can be crosslinked much longer until the entire coating mass becomes stiffer and still retains its effectiveness.

However, if a film of the same material and thickness is even more crosslinked, it will form a hard, glass-like coating that occasionally

buy in. In general, organosiloxanes grow with special alkyl substituents the viscosity with the chain length. If more of the Substituents consists of hydrogen atoms, the organosiloxane can easily be crosslinked by oxidation. at Presence of aromatic substituents, such as. B. phenyl groups, it is less sensitive to oxidation.

If there is no or only slight crosslinking, the dimethylsiloxanes are liquid. With increasing chain length of the siloxane, the viscosity of the liquid increases to a rubbery state. When a liquid dimethylsiloxane is crosslinked, it turns into a gel and becomes with increasing crosslinking harder and more fragile, until it finally loses its gel-like character and becomes increasingly one hard and inflexible resinous material becomes.

Obviously, the ratio of structural units of the organosiloxane is determined by its composition, and therefore its mean functionality is indicated by both the mean or empirical composition and the structural formula. Accordingly, the mean compositions correspond to [(CH ₃ ) 1, Si O] _n and [(CH ₃ ) HSiO] _n organosiloxane polymers composed of bifunctional units, such as. B. a viscous liquid, a soft rubber or an elastomer, while a combination [CH ₃ Si O ₁ ^] _n corresponds to a polymer that consists of units with an average functionality of three and is therefore a largely cross-linked siloxane resin. Since the composition is CH ₃ SiO _1-5 in the same way either a completely off

CH ₃

- O - Si - O units

composite polymer or one which can be composed of the same number of

CH ₃ O

—O — Si — O and —O — Si — O units

CH,

it follows that the average composition is the usual way of describing a given siloxane polymer is. For the person skilled in the art, however, it is evident that very high proportions of tri- or tetrafunctional Units even with compensation by a corresponding number of monofunctional Units in the condensation process stereochemical disturbances and thereby a change in the crosslinking properties of the polymer. For this practical reason, every organosiloxane system must and indeed in any organosilicon-containing polymer system, the substitution with trifunctional - or tetrafunctional - plus corresponding ones monofunctional units are limited to a minimum so that they are not used in the Crosslinking to the desired soft gel adhering to the steel interferes.

The organosiloxanes used for crosslinking on the blade itself can, with regard to the in The preceding paragraphs are generally defined as initially liquid polymers that composed of molecules in the form of a chain of alternating silicon and oxygen atoms are, where one of the many silicon atoms within the chain is substituted by two groups is. A considerable number of these groups must be composed of either methyl groups or hydrogen atoms exist to enable crosslinking to form the desired soft gel. It can but also all possible other groups, such as ethyl, n-propyl, isopropyl, η-butyl, n-amyl, Vinyl, allyl, or phenyl, provided yours

The proportion remains low enough that the crosslinking does not lead to the desired adherence to the steel upset soft gel. In the case of hydrogen as the only substituent, the liquid polymer tends to too strong networking up to the undesirable hard-

th, glass-like state. Both the lower and the upper limit of the number of other substituents replaceable hydrogen atoms depends on their nature. For example, from the hydrogen atoms 40 to 100% by methyl groups, but only about 40 to 80% by ethyl groups and even only 40 to 50% can be replaced by n-propyl or n-butyl groups. Although also organosiloxanes applied to blades with an even higher proportion of hydrogen atoms than those mentioned above

ao and then be effective for a short time after networking, experience has shown that Such organosiloxanes tend to be stored for a normal length of time between manufacture and use networked too much by the consumer.

Therefore, such organosiloxanes can only be used under special conditions, for example when immediately prior to application being applied to the cutting edges. Phenyl, isopropyl, Vinyl, allyl and n-amyl groups may only be present in the molecule if other, additional substituents are present as hydrogen alone.

In the case of dimethylsiloxane, about 15% of the methyl groups can be replaced by phenyl groups, up to about 30% by isopropyl groups, up to about 50% by n-propyl or n-amyl groups and up to about 70% 'are replaced by ethyl groups without affecting the performance of the Material of the adhesive coating is destroyed. In the case of methyl hydrogen siloxane, on the other hand, from up to 40% of the methyl groups have been replaced by phenyl groups and up to about 60% by isopropyl groups will. Furthermore, in the dimethylsiloxane, a very small part of the methyl groups can be replaced by vinyl or Allyl groups are replaced.

The polymers can be of a cyclic or open-chain nature, with the two end groups in the latter case the individual polymer chains are usually composed of hydroxyl or aliphatic or aromatic Groups exist.

The desired organosiloxanes can also be referred to as originally liquid polymers with a structure according to the formula [(RR'-Si-O)] ", in which R or R 'is hydrogen or organic groups as defined above and η has an average value of up to 5000 and mean about it.

Experience has shown that the polymers are low

.. «values are difficult to use for various reasons. If their boiling points are too low,

they evaporate and cannot be networked at the job site. If they have non-condensable end groups, such as B. trimethylsiloxy groups, and have a low molecular weight, they evaporate not, but they do not form the desired soft gel. In both cases, however, may be due to the presence a very small amount of higher polymer material in the mixture is a useful coating develop. Low molecular weight materials with

condensable end groups, such as. B. hydroxyl groups are more useful than those with non-condensable End groups. In the case of linear dimethylsiloxanes with terminal hydroxyl groups or cyclic dimethylsiloxanes, in which at If the ring breaks condensable end groups, a polymer with an n-value can be formed of 7 or above easy to use. Preferably difficulties are encountered through the use of materials with much higher molecular weight avoided.

Obviously, a material can also be applied to the blade cutting edge that is not itself an originally liquid organosiloxane, but is only converted into a siloxyn on site. If, for example, octamethylcyclotetrasilazane [(CH ₃ ) ,, - Si — NH] _{4 is} applied to a razor blade cutting edge and left in the air for a long time, it hydrolyzes to form a liquid siloxane that can easily be crosslinked in the usual way.

The best results are obtained with those organosiloxanes in which R consists of methyl and R 'consists of hydrogen or methyl. Among them, in turn, the liquid methyl hydrogen siloxanes of the formula [(CH ₃ ) HSiO] _n , in which η has the mean value mentioned above, are particularly preferred, but liquid dimethylsiloxanes with a higher mean value are also very useful. Obviously, the compositions given above are only those of an intermediate nature, and any given linear polymer molecule need not be made up of a chain of consistently identical units. In fact, mixtures of different polymeric molecules can also be used, provided they have the mean composition given above. So z. B. methyl hydrogen siloxane from a mixture of polymer molecules with

CH ₃

- Si - O groups

CH ₃

and polymer molecules
H

• Si —O groups

as well as polymer molecules
CH ₃

- Si - O groups

40

45

-50

55

60

exist.

In fact, the material can also contain polymer molecules, each made up of two or even all of them There are three types of groups mentioned above. Such mixtures can, for example, by common Hydrolysis of a combination of dimethyldichlorosilane, methyldichlorosilane and dichlorosilane obtained will.

Of course, the optimal crosslinking conditions for a polymer of the formula [(CH ₃ ) ₂ Si O] _{n are} different from those for a polymer of the formula [(CH ₃ ) H Si O] _n , since the silicon-hydrogen bond is known to be lighter than the silicon -Methyl bond oxidized. Similarly, the crosslinking conditions must be matched to the molecular weight of the siloxane composition, since a volatile polymer with a low molecular weight already evaporates at too high a temperature before it can crosslink by oxidation.

The originally liquid polymer is preferably applied to clean surfaces in some known manner Applied to the razor blade cutting edge by, for example, either inserting the blade edge into the liquid Polymer is immersed or countersunk or the liquid polymer is sprayed onto the cutting edge, is applied by means of a capillary or by pulling off the blades. In order to achieve the best Adhesion or bonding of the polymer to the underlying blade part is expedient the polymer application all foreign material, such. B. organic fat or oil, removed from the blade surfaces. This can be done, for example, by cleaning the blade with a volatile solvent, such as B. benzene, trichlorethylene or carbon tetrachloride, washes off and then dries. To the It may be desirable to facilitate the application of the polymer to the sharpened razor blade edge Polymer by adding a suitable inert, volatile, organic solvent or diluent, such as B. carbon tetrachloride, hexamethyldisiloxane or 1,4-dioxane to dilute. After covering a blade cutting edge and evaporation of any solvents or thinners the liquid polymer can be crosslinked to form a gel material at the application site.

When crosslinking is done by heating the coated blades in a hot air oven then the required amount of time and temperature depends on both the volume of air inside Furnace and the air circulation speed as well as the size, mass and shape of the individual blades and their coating and on the total number of blades simultaneously present in the furnace, because of these factors the rate of heat transfer to the coating and its rate of heating depends. If the crosslinking remains so inadequate that the organosilicon-containing Polymer remains essentially liquid, like it is not much more effective than other liquids z. B. lubricating oil, and can therefore neither improve the apparent sharpness of the blades nor the he. reduce necessary pulling force. But even if the networking time is too long, the desired results do not occur Results on, and under certain circumstances, even over-networking in particular if the coating is initially fairly thick, one Blade that is more deficient than the original, uncoated blade. For the purpose of avoidance In many cases, it is advisable to use the heated blade quickly if the crosslinking is too strong to cool in a stream of air.

In the case of siloxane chains of the formula [(CH ₃ ) HSiO] _n , effective crosslinking can be achieved by heating the blade to about 150 ° C. for about 15 minutes in the presence of air. Generally speaking, is a

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Heating at 140 to 170 ° C for 2 to 15 minutes in the presence of air is preferred. However, effective crosslinking can also be achieved if the blades coated with the liquid polymer are kept at a lower temperature for a longer period of time, for example for 2 ¹ k hours at about 95 ° C., or, on the other hand, for a shorter period of time at higher temperatures, for example 20 seconds long to 200 ⁰ C, heated. If desired, it is also possible to use additives which are either chemically inert or, as in Examples 2 and 3, chemically active.

The time and temperature required for the desired degree of crosslinking can thereby be reduced be that the liquid polymer composition with suitable, known catalysts added, to which, for example, choline bicarbonate, ammonium hydroxide, piperidine, dibutyltin dilaurate, Include tin laurate and zinc naphthenate. The smallest possible networking time for any given Starting material from liquid, organosilicon-containing polymer also depends on the chain length, the longer the chain, the lower the temperatures required and the times required get shorter.

When the liquid, organosilicon-containing polymer has achieved the desired degree of crosslinking, can be determined by simple investigations. If, in the case of liquid siloxanes, the chains of which are composed according to the formula [(CH ₃ ) HSiO] _n , the material is completely removed when wiped with felt or cloth or is completely dissolved away by carbon tetrachloride at room temperature, then the crosslinking is below the minimum value required . One of the best types of exams, however, is of course to shave with treated and untreated blades and compare the results.

Some embodiments of the invention are explained in more detail in the following examples. In in all cases except for example 8 the blades used consisted of hardened, lacquered, double-edged blades Safety razor blades made of standard carbon steel 0.152 mm thick, namely the blades known under the trade name of Gillette Blue Blades blades. In all examples, by actual shaving tests, the marked improvement in the shaving properties of the treated blades compared to a similar but untreated blade.

Example 1 . ""

An endless steel conveyor belt that protrudes on its upper, horizontal surface with Was provided with lugs to keep blades with their edges parallel to the feed direction, was mounted in such a way that it continuously slides the blades into, through it, an elongated heating furnace led through and out of it. The tape was less than half the blade wide and 1.25 mm thick, and its retaining lugs were arranged so that successive blades were a little less than 10 mm diverged. The furnace consisted of a 0.9 m long, essentially rectangular block of aluminum, which weighed the multiple of an equally long band and blade length and an inner one in the middle arranged longitudinal channel, which in cross-section was only slightly larger than the band and blades was. Electrical resistance heating strips were arranged on the top and bottom of the furnace Temperature was regulated by thermocouples arranged in bores of the furnace near the passage. The belt speed was adjusted so that each blade was allowed to pass through the oven heated to 160 ° C.

The blades to be treated were washed with trichlorethylene, dried, reapplied to the moving conveyor belt and conveyed through an application station which was located about 1.1 m in front of the furnace entrance. In this application station, each blade was drawn with its two cutting edges in the longitudinal direction through narrow, open channels that were fed with a 12 percent by volume solution of methyl hydrogen siloxane in carbon tetrachloride. This siloxane corresponded to the formula [(CH ₃ ) HSiO] _n and had a reduced, specific viscosity of 0.08, measured using an Ostwald-Cannon-Fenske viscometer ASTM series 50. The test solution consisted of 5 ecm of a xylene solution which at 27 ° C. in 100 ecm solution contained 10 g of the silicon oxane to be investigated. As a result, each blade received a coating of this solution on both cutting edges. The carbon tetrachloride evaporated as the blades moved towards the furnace. After a single oven pass, the blades were allowed to air cool. The blades treated in this way had a coating of soft gel on their cutting edges, which adhered to the steel underneath and showed a pattern of seven interference fringes in the 0.025 mm wide zone adjoining the outermost edge.

Example 2

The procedure was the same as in Example 1 except that the coating material was 12 percent by volume Solution of the same organosiloxane in double-distilled hexamethyldisiloxane as solvent used, the solution at the same time still 1 percent by weight disperse, finely divided Molybdenum disulfide contained, as is commercially available under the trademark Molykote Type GX is. The finished blades had a coating of a steel adhesive on their cutting edges soft gel material, the coating shows no interference fringing pattern, "was 0.025 mm wide in the zone adjoining the outermost edge_ a thickness of less than 0.2μ.

Example 3

The procedure was the same as in Example 2, but the molybdenum sulfide was finely divided Replaced silica as used by Godfrey L. Cabot, Inc., under the registered trademark Cab-o-sil Fluffy 2491 is put on the market. The one formed on the cutting edges The coating consisted of a soft violin structure adhering to the steel and showed no interference fringes. Its thickness was therefore 0.025 mm in the width adjoining the outermost edge Zone less than 0.2μ.

Example 4

The procedure was largely the same as that described in example 1. The coating material

however, it was composed of a mixture of 1 part by volume of a solution of the methyl-hydrogen-siloxane according to Example 1 in 1 part by volume of 1,4-dioxane and the same volume of one added with vigorous stirring Mixture, half of which by volume consist of a 44 weight percent aqueous solution of choline bicarbonate and 1,4-dioxane. The entire mixture was applied before application let the blades stand for 15 minutes at room temperature. It was also compared to the example 1 increases the running speed of the belt conveyor so that each blade only lasts 9.5 seconds for the Oven passage required. It was found that each blade had one on its cutting edges on the underneath had a soft gel coating adhering to the steel, which was attached to the outermost edge subsequent 0.025 mm wide zone showed five interference fringes.

Example 5

A high molecular weight dimethylsiloxane of the formula [(CHg) ₂ SiO] _n was obtained by catalytic isomerization and polymerization of the cyclic tetramer and, according to the measuring method described in Example 1, had a reduced specific viscosity of 0.4, although the test solution was not 10 g, but only contained 5 g of siloxane in 100 ecm solution. The application was carried out in a similar manner to Example 1, except that a 12 percent by volume solution of this siloxane in carbon tetrachloride was used and the conveyor belt was stopped so long that each blade remained in the oven for 30 minutes. The blades treated in this way had a thin layer of soft gel adhering to the steel on their cutting edges, which had four interference fringes in the 0.025 mm wide zone adjacent to the outermost edge.

Example 6

In this case, ethyl-hydrogen-siloxane of the formula [(C ₂ H ₃ ) HSiO] _n and a reduced specific viscosity of 0.03, measured by the method according to Example 1, was used as the coating composition without any solvent. A stack of about 50 blades, which had previously been washed with trichlorethylene, dried and arranged with their flat sides aligned with one another and with their edges parallel to one another, were dipped by hand into a layer of the liquid siloxane so far that each of their sharpened edges was along its entire length just touched the liquid surface. The blades wetted in this way were then mounted on pairs of steel spindles, each blade being kept at a distance of about 1 mm from the one below in the stack with the aid of a pair of about 14 mm wide intermediate rings. Seven such spindle pairs with a total load weight of about 650 g were placed on a carrier in such a way that the edges of adjacent stacks of blades were about 6 mm apart, in a hot air oven set at 160 ° C (type Thelco No. 18-AD-9 from Precision Scientific Co.) and left in it for 20 minutes. The blades were then removed and allowed to air cool. Each blade had a thin layer of soft gel material adhering to the steel on its cutting edges, which showed five flexion seams in the 0.025 mm wide zone adjoining the outermost edge.

Example 7

The coating composition used in this example consisted of a 50 volume percent solution of n-Propyl-Hydrogen-Siloxane and was applied to the blades in the manner described in Example 6. The siloxane corresponded to the formula

ίο [(C ₃ H ₇ ) HSiO] _n and had a reduced, specific viscosity of 0.03, measured according to the method described in Example 1, but the xylene solution contained 20 g of siloxane in 100 ecm solution.

The blades were placed on their holding spindles in a hot air oven set at 160 ° C (Blue-M model OV-50 from Blue M Electric Co.), stored in it for 2V2 hours and then cooled in air. The finished blades had a thin one on their cutting edges that stuck to the steel

ao layer of soft gel material which is 0.025 mm wide in the one adjacent to the outermost edge Zone three boundary seams showed. In this case, too, the seams were all in the rear zone section grouped, while in the first, edge-adjacent zone quarter no diffraction fringes at all were visible.

Example 8

A 12 percent by volume solution of the methyl hydrogen siloxane according to Example was used as the coating compound 1 in twice distilled hexamethyldisiloxane used as a solvent. The coating compound was following the procedure of Example 1 on double-edged safety razor blades purchased over the counter applied from stainless steel. The finished blades had on their cutting edges a soft gel coating that adheres to the steel, the one adjacent to the outermost edge 0.025 mm wide zone showed three flexion fringes.

Example 9

In the manner described in Example 6, liquid, solvent-free ethyl-methyl-hydrogen-siloxane was applied to the blade edges. The siloxane had the formula [RRSiO] _n , where 13 "Vo of the R groups consisted of ethyl, 40% of methyl and 47% of hydrogen, and had a specific viscosity of 0.06 according to that described in Example 1 Investigation method.

After wrapping their edges, the blades were stacked on spindles and held for 6 minutes heated in a hot air oven according to Example 7. After cooling in air, the blades had on theirs Cutting edges have a thin coating of soft gel material adhering to the steel, which is used in the the outermost edge of the adjacent 0.025 mm wide zone showed six interference fringes.

Example 10

Liquid ethyl-methyl-hydrogen-siloxane of the formula [RRSiO] _n , in which the R groups consisted of 29% ethyl, 23% methyl and 48% hydrogen, was used as the coating material. According to the measuring method described in Example 1, the siloxane had a reduced specific viscosity of 0.02. The coating material was applied by hand to the blade edges in the manner described in Example 6, and the

15 16

coated blades were stacked on spindles, Example 14

For 10 minutes in an oven according to Example 7, liquid phenyl-methyl-

heats and then cooled in air to room temperature. Siloxane of the formula [RRSiO] _{n is} used, in which the cools. On their cutting R groups, 15 "/ O of phenyl and 85% of edges consisted of a firmly adhering coating of soft 5-methyl. Determination method described in Example 1, a hard 0.025 mm wide zone six interference-reduced, specific viscosity of 0.02.

. . applied by hand to the edge of the blade,

Example 11 _{1Q and} ut> _Erzo g _ene n blades were on spindles

In this case, the coating was solvent-stacked and free, liquid ethyl-methyl-siloxane of the formula as in Example 7 was heated for 30 minutes in the same oven. After cooling in [RRSiO] _n , in which the R groups were used at 30 ° / »air to room temperature, the finished blades were made of ethyl and 70% of methyl. The one layer of polymer material siloxane adhering to the steel had, according to the 15 described in Example 7, in the form of a soft gel structure, which in the test method had a reduced, specific outermost edge 0.025 mm wide zone twelve inter-viscosity of 0.09. The siloxane application on the reference seams showed.
Blade edging was done by hand in the manner described in Example 6, and the Klin Example 15
genes were stacked on spindles, for 5 hours in 20

heated in an oven according to Example 7 and finally the coating composition in this case was a

cooled in air to room temperature. The finished 20 percent by volume solution of modified Me blades has a layer of ethyl hydrogen siloxane on their cutting edges in double-distilled hexa from adhering polymeric material in the form of a methyl disiloxane used as a solvent. The soft gel structure, which in this case had no inter- 25 methyl-hydrogen-siloxane, showed the middle merging seams, because its thickness in the outer composition [(CH ₃ ) HSiO] _n , and its polymer chains next to the edge, was 0.025 mm Zone ended with the group —OCH ₂ (CF ₂ ) ₃ CF ₂ H. was below 0.2 µ. According to the method described in Example 12, the polymer had

. . _{1 1} benign examination method a reduced, special

Example Ll _{30 fish} viscosity of 0.03. The crowd was in the

Liquid n-butyl-water was used as the coating compound in the manner described in Example 6 on the blade material siloxane of the formula [(C ₄ H ₉ ) HSiO] _n , applied to the edges, and the coated blades had a reduced specific viscosity of 0, 14 were stacked on spindles and had for 10 minutes. The viscosity measurement was carried out after heating in the same oven as in Example 7. According to the method described in Example 1, but the test solution contained not 10 g, but only 2 g of the siloxane had been cooled in air to room temperature. The finished blades had a 100 ecm solution on their cutting edges. The material was applied to the blade edges of the 0.025 mm adjacent to the outermost edge in the layer of soft violin structure adhering to the steel, the manner described in game 6, and the coated blades remained wide zone showing twelve interference fringes.
For 24 hours in the 40 described in Example 7

Oven and were then air cooled. The ferti- Example 16

gen blades have a on their cutting edges

Layer of adhesive polymeric material in liquid methyl-water-

Form of a soft gel structure, which in the outer material siloxane of the formula [(CH ₃ ) HSiO] _n used, the most edge adjacent 0.025 mm wide zone 45 that showed interference fringes described in Example 1. search method had a reduced specific viscosity of 0.08. About 1000 blades were made

Example 13 first washed with trichlorethylene, dried

and then on their flat sides with

As the coating composition, liquid methyl-water was stacked towards the edges. The stack was in hydrogen siloxane with a reduced, specific hot air oven heated to around 170 ° C (type Viscosity of 0.08, measured according to the Blue M model OV-50 from Blue M Electric Co. in Example 1) method described. Put the material in and leave it in for 26 minutes, was carried out according to the procedure described in Example 6. During this time, the blade edges heated up Ren applied to the blade edges and cross-linked, 55 to 160 ° C. The stack of blades heated in this way was now however, the oven was removed from the oven at a temperature of 167 ° C for 30 seconds instead of 160 ° C and the blades in it and during this time on the edges with the only 3 minutes remained. sprayed siloxane described above. The so over-

After cooling in air, the drawn blades were then subsequently an additional 10 mi-coated Blades refluxed for 21 hours in the same oven for 60 minutes, again temperature in a under the name Soxhlet device and so long in about 10 ° C cooler known device extracted with benzene. Air was retained here until it settled down to approximately 35 ° C Part of the gel on the cutting edges had cooled. The finished blades had on theirs materials dissolved and taken away by the benzene. Cutting edges a thin layer adhering to the steel The benzene extracted blades then became 6g of soft gel structure. The coating showed in dried in air at room temperature and showed no interference fringes in this case, since it was in the in the 0.025 mm outermost edge adjacent to the outermost edge wide zone five interference fringes. Zone was less than 0.2μ thick.

Example 17

In this case, the liquid dimethyl-sul-polyester of ethylene glycol was used as the coating material used of the middle composition

[(CHg) ₂ SiOCH ₂ CH ₂ O] ,,

and according to the test method described in Example 1, a reduced specific viscosity of 0.008. The material was applied to the blade edges in the manner described in Example 6 and the coated blades were placed in the same oven as in for 2 hours Example 7 heated and then cooled to room temperature in air. The finished blades bore on their cutting edges a layer of adherent polymeric material in the form of a soft Gel structure. The coating showed no interference fringes because its thickness was in that of the outermost edge adjacent 0.025 mm wide zone was less than 0.2 μ.

Example 18

A modified, liquid dimethylsiloxane, in which the silicon atoms were partially replaced by tin atoms. Its composition corresponded to the formula

[(CH ₃ ) ₂ SiO (CH ₃ ) ₂ SnO] _n

with an atomic ratio of about 19: 1 between Silicon and tin. According to the test method according to Example 12, the liquid polymer had a reduced specific viscosity of 0.01. The mass was made in the manner described in Example 6 Hand applied to the blade edges, heated in the same oven as Example 7 for 2 hours and finally cooled to room temperature in air. The finished blades had a coating made of adhering polymeric material in the form of a soft gel structure. The coating showed no interference fringes, since its thickness is less in the 0.025 mm wide zone adjacent to the outermost edge than 0.2 µ.

Example 19

Liquid vinyl-methyl-siloxane was used as the coating compound, which _{corresponded to the formula [RRSiO] n} , in which the R groups consisted of 0.5% vinyl and 99.5% methyl. According to the measuring method described in Example 5, the siloxane had a reduced specific viscosity of 0.009. The material was applied to the blade edges and crosslinked in the oven in the manner described in Example 7, but with a residence time of 75 minutes. After cooling in air to room temperature, the blades had on their cutting edges a thin coating of soft gel material adhering to the steel, which however in this case showed no interference fringes because its thickness in the 0.025 mm wide zone adjacent to the outermost edge was less than 0.2 μ was.

Example 20

Liquid allyl-methyl-siloxane of the formula [RRSiO] _n , in which the R groups consisted of 0.5% allyl and 99.5% methyl, was used as the coating compound. According to the measuring method described in Example 5, the siloxane had a reduced specific viscosity of 0.106. The material was applied to the blade edges and crosslinked in the manner described in Example 1, but the speed of the belt through the oven was adjusted so that each blade remained in it for 2 minutes. The blades treated in this way had on their cutting edges a thin layer of soft gel material adhering to the steel, which showed ten interference fringes in the 0.025 mm wide zone adjacent to the outermost edge.

Example 21

A liquid n-amyl-methyl-siloxane of the formula [RRSiO] _n , in which the R groups consisted of 50% amyl and 50% methyl, was used as the coating material. According to the method described in Example 1, the siloxane had a reduced specific viscosity of 0.015. After application to the blade edges, the material was crosslinked in the manner described in Example 7, but with the blades remaining in the oven for 3 hours. After cooling in air to room temperature, the blades had on their cutting edges a thin coating of soft gel material adhering to the steel, which showed six interference fringes in the 0.025 mm wide zone adjacent to the outermost edge.

Example 22

Liquid isopropyl-methyl-hydrogen-siloxane of the formula [RRSiO] _n , in which the R groups consisted of 30% isopropyl, 20% methyl and 50% hydrogen, was used as the coating material. According to the test method described in Example 1, the siloxane had a reduced specific viscosity of 0.06. The material applied to the blade edges was crosslinked in the manner described in Example 7, but with the blades remaining in the oven for 30 minutes. After cooling in air to room temperature, the blades had on their cutting edges a thin coating of soft gel material adhering to the steel, which showed six interference fringes in the 0.025 mm wide zone adjacent to the outermost edge.

The application of the coating can represent a work step during the blade manufacture. For example, a thin strip of high-carbon steel in the rolled state, its width is slightly larger than that of the finished razor blades, initially a hole and notch punch treatment are subjected and then hardened. The strip is then placed on a longitudinal edge or sharpened both long edges. After this sharpening process, the coating according to the invention applied to the sharpened edges and crosslinked. The next step is splitting of the tape into the individual blades. Of course, if desired, the coating can only be applied after Tape division process are applied. Of course, the term "blades" also includes very long, flexible, ribbon-shaped blades like those used in ribbon-blade razors.

Claims (1)

PATENT CLAIMS: 1. Use of a coating made of a silicon-containing one Organopolymer on metallic 109 747/63 Cutting edges to improve the shaving properties of safety razor blades by a applied to their cutting edges and through partial or total crosslinking of the polymer Material on the blade adheres better to the side surfaces of the cutting edges Coating. 2. Blade using the coating according to claim 1, characterized in that the Polymer contains a plurality of siloxy groups. 3. Blade according to claim 2, characterized in that the coating consists of the crosslinking product of a polymer which is a chain of alternating silicon and oxygen atoms, with each of a considerable number Silicon atoms are bonded to two substituents, some of which are hydrogen or Methyl and the remainder of methyl, ethyl, n-propyl, η-butyl and only in the case of presence a substituent other than hydrogen is isopropyl, n-amyl, vinyl, allyl, or phenyl. 4. Blade according to claim 3, characterized in that the substituents are hydrogen and methyl. 5. Blade according to claim 4, characterized in that about half of all substituents consists of hydrogen and the remainder of methyl. 6. Blade according to claim 5, characterized in that the substituted with hydrogen and methyl Polymer subjected to crosslinking for 2 to 15 minutes in hot air at 140 to 170 ° C was. 7. Blade according to claim 3, characterized in that the polymer substituents for the lesser Part of allyl and vinyl and the rest of methyl. 8. Blade according to claim 2, characterized in that the coating of the crosslinking product a silyl polyester, in particular a dimethylsilyl polyester of ethylene glycol. 9. Blade according to claim 2, characterized in that the coating consists of the crosslinking product a polymer that is a chain of alternating silicon and oxygen atoms having, wherein a small part, for example 5%, of the silicon atoms is replaced by tin and preferably two methyl substituents are bonded to each silicon and tin atom. 10. Blade according to one of claims 1 to 9, characterized in that the coating tapers towards its edge. 11. Blade according to one of claims 1 to 10, characterized in that the blade is made of steel consists. 12. A method for making a coated safety razor blade according to any one of Claims 1 to 11, characterized in that there is a coating on a blade cutting edge applied polymeric material and this cross-linked to form a gel adhering to the cutting edge will. 13. The method according to claim 12, characterized in that an organosilicon-containing, polymeric material, such as an organosiloxane, applied to the cutting edge and at higher temperature in the air is crosslinked to a soft gel. 14. The method according to claim 13, characterized in that the blade prior to application of the coating is heated to a higher temperature. 15. The method according to any one of claims 12 to 14, characterized in that the coating after hardening a steel blade is applied to its cutting edge. 16. The method according to any one of claims 12 to 15, characterized in that the cutting edge cleaned of foreign material prior to application of the coating, for example with a volatile solvent is washed. 17. The method according to any one of claims 12 to 16, characterized in that the coating and networking are carried out as sections of a sequence of processing steps, These include the hardening of a strip of high-carbon steel and the sharpening of at least one The longitudinal edge of the tape and the splitting of the tape into individual blades belong. Considered publications:
U.S. Patent Nos. 2462242, 2470 593;
Journal: Military Medicine, Vol. 121 (December 1957), pp. 397 to 402;
Prospectus 8-206 from Dow Corning Corp., Midland Michigan, November 1953. © 109 747/63 11.61