Polymeric cutting edge structures and method of manufacturing polymeric cutting edge structures
10518429 ยท 2019-12-31
Assignee
Inventors
- Matthias Gester (Farnborough, GB)
- Roman Kiyan (Hannover, DE)
- Ulf Hinze (Garbsen, DE)
- Kestutis Kurselis (Garbsen, DE)
Cpc classification
B29C37/0028
PERFORMING OPERATIONS; TRANSPORTING
B26B21/4068
PERFORMING OPERATIONS; TRANSPORTING
B29K2995/0027
PERFORMING OPERATIONS; TRANSPORTING
B29K2833/12
PERFORMING OPERATIONS; TRANSPORTING
B29C33/3857
PERFORMING OPERATIONS; TRANSPORTING
B29K2105/0005
PERFORMING OPERATIONS; TRANSPORTING
B29C33/3842
PERFORMING OPERATIONS; TRANSPORTING
B29C33/005
PERFORMING OPERATIONS; TRANSPORTING
B29K2105/0094
PERFORMING OPERATIONS; TRANSPORTING
B29L2031/756
PERFORMING OPERATIONS; TRANSPORTING
B29K2883/00
PERFORMING OPERATIONS; TRANSPORTING
B29L2031/72
PERFORMING OPERATIONS; TRANSPORTING
B29C35/0805
PERFORMING OPERATIONS; TRANSPORTING
B29C39/10
PERFORMING OPERATIONS; TRANSPORTING
B29C39/02
PERFORMING OPERATIONS; TRANSPORTING
B29C39/026
PERFORMING OPERATIONS; TRANSPORTING
International classification
B29C39/00
PERFORMING OPERATIONS; TRANSPORTING
B29C35/08
PERFORMING OPERATIONS; TRANSPORTING
B29C39/02
PERFORMING OPERATIONS; TRANSPORTING
B29C39/10
PERFORMING OPERATIONS; TRANSPORTING
B29C33/00
PERFORMING OPERATIONS; TRANSPORTING
B29C37/00
PERFORMING OPERATIONS; TRANSPORTING
B29C33/44
PERFORMING OPERATIONS; TRANSPORTING
B29C33/38
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A functional polymeric cutting edge structure and methods for the manufacturing cutting edge structures using polymeric materials are provided. A razor blade for use in a razor cartridge or a blade box for assembly in a razor cartridge frame may be formed using the present invention.
Claims
1. A method for manufacturing at least one cutting edge structure comprising the steps of: providing a first polymeric material in liquid form in a container; providing at least one cutting edge template within said first polymeric material; curing said first polymeric material while said at least one cutting edge template is disposed in said first polymeric material to form a base structure; removing said template to obtain a cavity in said base structure; filling said cavity with a second material, said second material being a precursor for a polymeric material; curing said second material; and separating said base structure and said cured second polymeric material, said at least one cutting edge structure comprised of said cured second polymeric material, wherein said at least one cutting edge structure is a razor blade or a portion of a blade box and wherein a tip radius of said at least one cutting edge structure is less than 1 micrometer.
2. The method of claim 1, wherein said second material being said precursor material for said polymeric material is comprised of a monomer material, an oligomer material, or any combination thereof.
3. The method of claim 1, wherein said at least one cutting edge structure comprises a gothic arch, a roman arch, or one or more undercuts.
4. The method of claim 1, wherein said first polymeric material is comprised of Poly (methyl methacrylate) (PMMA) or Polydimethylsiloxane (PDMS).
5. The method of claim 1, wherein said second material being said precursor material for said polymeric material is comprised of an acrylic material or an epoxy material.
6. The method of claim 1, wherein a viscosity of said second material being said precursor material for said polymeric material is less than about 10,000 centiPoise.
7. The method of claim 1, wherein said base structure is comprised of only one part.
8. The method of claim 1, wherein the cavity is entirely comprised in a single part in said base structure.
9. The method of claim 1, wherein a portion of the cavity is not enclosed by said base structure after formation.
10. The method of claim 1, wherein at least one of said second material being said precursor material for said polymeric material, said cured second polymeric material and at least one side of the cavity is transparent to electro-magnetic radiation at a wavelength in the range of 250 to 1500 nanometers.
11. The method of claim 1, wherein the separating step comprises physical or chemical removal of the base structure from said cured second polymeric material cutting edge structure.
12. The method of claim 1, wherein a photo-initiator of about 1 to about 3% by weight of composition is added to the second material being said precursor material for said polymeric material prior to the curing step.
13. The method of claim 1, wherein the first polymeric material is compliant.
14. The method of claim 1 wherein said steps of curing comprise cross-linking or polymerization.
15. The method of claim 1, wherein said steps of curing are mediated by heat, light, or a combination thereof.
16. The method of claim 15, wherein one or both of said curing steps comprise UV light.
17. The method of claim 1, further comprising the step of securing said razor blade or said blade box into a razor cartridge housing or frame.
18. The method of claim 1 wherein said blade box is comprised of different types of cutting edge structures.
Description
DETAILED DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE INVENTION
(12) The methods of the present disclosure provide for the manufacture of cutting edge structures (e.g., razor blades which may be used in shaving devices or razors). Specifically, disclosed are methods for manufacturing cutting edges or razor blades for shaving devices from polymeric material.
(13) As used herein, a polymeric material signifies a material that is formed of a polymer, the latter being a large, chain-like molecule made up of monomers, which are small molecules. Generally, a polymer can be naturally occurring or synthetic. In the present invention, preferred embodiments comprise synthetic or semi-synthetic polymers. The synthetic or semi-synthetic polymer materials generally can occur in two forms or states. The first state may be a soft or fluid state and the second state may be a hard or solid state. Generally synthetic polymers are molded or extruded when in the first state (e.g., liquid or soft) and subsequently formed into an object that is in a second state (e.g., hard or solid). In some instances, the material is reversible (e.g., a material in the second state can be converted back to its first state) while in others, the polymerization is irreversible (e.g., the material cannot be converted back to its first state).
(14) A thermoplastic polymer is a type of reversible polymer that is in a soft or liquid first state at elevated temperatures (e.g. 200 C. and above) and converts to a solid second state when cooled to ambient temperatures. Thermoplastic polymers are typically used for injection molding or extrusion techniques of the prior art.
(15) For those polymeric materials where the second state is obtained from the first state via irreversible polymerization, the first state of the polymeric material may generally be thought of as being a precursor for the second state of the polymeric material. As such, in the present invention, a polymeric material may be generated from a precursor material or a material in a first state.
(16) The materials that are generally desired for the present invention cutting edge structures are materials in the first, soft or liquid, states which comprise monomers or short chain length (e.g., low molecular weight) polymers known as oligomers or both. Both monomers and oligomers are referred to herein as precursors. These precursors are converted into long chain length polymeric material in the second, solid state through a polymerization or cross-linking process, herein referred to as a curing process. Curing the precursor material can generally be achieved under the influence of heat, light, ionic or high energy radiation, or any combination thereof. After curing, the solid polymeric material is achieved.
(17)
(18) In
(19) Generally, it is desired that the first polymeric material 220 of the present invention used to form the base structure 405 has a first uncured fluid state, so that it can be dispensed into the container 105 at step 200a. There is generally no limitation to the types of first polymeric material that can be used to form the base structure 405. In a preferred embodiment, the first polymeric material and related precursors are Poly (methyl methacrylate) (PMMA), Polydimethylsiloxane (PDMS), or other materials commonly used for micro-replication or nano-imprint lithography, and as such, the first polymeric material 220 of step 200a is preferably comprised of SYLGARD 184 from Dow Corning. The viscosity of SYLGARD is about 5100 centiPoise. The container 105 may be kept or removed at the end of the process as will be described below.
(20) It should be noted that the base structure 405 can be considered to be a portion of a mold that will form the cutting edge structure (e.g., razor blade). In the flow diagram 20a of the present invention, the base structure 405 effectively represents a single part mold which cannot generally be split into further parts. The base structure 405 can be considered to be a half of a typical mold (e.g., the bottom half) since the other (e.g., upper half) half is not a component of the present invention. This contrasts the base structures of the prior art shown in
(21) A cutting edge template 310 is inserted into the liquid first polymeric material 205 at step 300a. The cutting edge template 310 may be of any type desired, but is generally preferably a three-dimensional stainless steel blade of the type shown in
(22) After the cutting edge template 310 is inserted into the first polymeric material and while the template 310 is disposed in the first polymeric material 205 at step 300a, the first polymeric material 205 is polymerized at step 400 such that the liquid first polymeric material 205 becomes a solid polymeric material, thereby forming the base structure 405. For example, if the first polymeric material 205 is comprised of PDMS, the PDMS is heated so as to become cured or polymerized. PDMS typically cures or solidifies through a chemical reaction involving water (e.g., absorbing water from the air) which is not reversible. While the process to fully cure the material may generally be a relatively slow process, it can preferably be accelerated with heat 420.
(23)
(24) At step 300b in
(25) The base structure 405 can be considered to be a portion of a mold that will form the cutting edge structure (e.g., razor blade). As with flow diagram 20a of
(26) It should be noted that the process steps beyond step 300a in
(27) It should be noted that, as shown in
(28) As shown in step 600, the cavity 510 formed in the base structure 405 made from a first polymeric material 220 is filled with a second polymeric material 620, generally in a form of a precursor for the second polymer. A precursor in the present invention may preferably be a monomer or a short chain length or low molecular weight oligomer material.
(29) Desirably the filling or pouring step 600 of the present invention occurs at ambient temperature ranging from about 10 degrees Celsius to about 40 degrees Celsius or may be heated up to 100 degrees Celsius to further reduce its viscosity. While generally there is no limitation to the types of second polymeric materials that can be used to fill the cavity, it is desirable that the polymeric precursor be more fluid and less viscous at ambient or near ambient temperatures than polymeric materials used in melt flow processing in order to achieve full penetration of the material in the cavity 510 and to fill the cavity 510 with a shape of a razor blade and tip desired. As such, a preferred viscosity of the second polymeric material precursor of the present invention is less than about 10000 centiPoise, more preferably less than about 5000 centiPoise, and most preferably about 3000 centiPoise or less.
(30) In the present invention, the second precursor material is preferably an acrylic based material, more preferably a polymer with monomer or oligomer formulations such as Femtobond 4B, and most preferably polymeric materials from the ORMOCER family, such as ORMOCORE, supplied by Microresist Technology GmbH. The ORMOCORE material has a viscosity of about 2900 centiPoise at ambient temperature. Another material named E-SHELL 300 which may be used as a precursor has a viscosity of about 340 centiPoise. The precursor material has a viscosity that is lower than the viscosity of the base structure or first polymeric material. It is noted in the present invention that a non-polymerized material, such as ORMOCORE, may be heated, up to 100 degrees Celsius to further reduce the viscosity. Generally, heating above 100 degrees Celsius may undesirably result in shrinkage when cooling down the cured structure.
(31) Alternatively, epoxy based materials, such as SU8 supplied by MicroChem, with a range of viscosities from 2.5 to 1250 centiPoise can be utilized as the second polymeric material.
(32) A photo-initiator of about 1 to about 3% by weight of composition may be added to the second polymeric material prior to the curing step 700 in
(33) The curing of the second polymeric material 620 to create a solid polymer 710 is performed at step 700 in
(34) In a preferred embodiment, the first polymeric material 220 and related precursors that form the base structure 405 are Poly (methyl methacrylate) (PMMA) or Polydimethylsiloxane PDMS). The material to form the base structure is preferably compliant, signifying that the material is flexible or deformable, so that the replicated cutting structure 710 formed from the second material, such as ORMOCORE or Femtobond 4B or SUB, can be easily removed from the base structure 405 after curing. With a PDMS-formed base structure 405, the elasticity and low surface energy properties of the PDMS material allow desirable removal of the cutting edge template 310. The elasticity provides deformation of the base structure 405 to release the cutting edge template 310 while also allowing the base structure 405 to return to its original shape after the cutting edge template 310 is removed. The low surface energy of the PDMS material prevents sticking of the cutting edge template 310 to the base structure 405 and also prevents damage to the base structure 405 during removal. Having these two properties, the base structure material plays an advantageous role in assisting the removal of the cutting edge template.
(35) At step 800, the base structure 405 is removed from the cutting edge structure 810. The base structure can be removed by physical or chemical means. A physical removal may include bending the base structure 405 apart and away from the cutting edge structure 810. If the base structure is removed by physical means, the container 105 may need to be first separated from the base structure. In some cases, the base structure 405 may have a rubbery attribute making a physical removal between the base structure and cutting edge structure and/or the container 105 feasible. A chemical removal process may include dissolving the base structure 405. If the base structure is dissolved then the container 105 may remain. The type of chemistry for dissolving the base structure may include organic solvents and if made from PMMA may include solvents such as acetone, acetonitrile, 1,2-dichloroethane, and dichlorobenzene, and if made from PDMA, may include solvents such as solution of TBAF (tetrabutylammonium fluoride) in NMP (N-Methylpyrrolidinone) or in DMF (dimethylformamide) or in THF (tetrahydrofuran) or in PMA (propylene glycol methyl ether acetate) or any combination thereof.
(36) The removal process may be achieved by dissolving, wet etching (e.g., via a chemical solution), melting, or any combination thereof.
(37) The cutting edge structure 810 represents the structure in the shape of a final cutting edge or razor blade edge.
(38) Flashing has been avoided with the present invention process since the base structure of the present invention is capable of forming the polymeric blade within one portion of the base structure as the base structure is formed of one part as opposed to the two mating parts or halves of the prior art (
(39) In
(40) The tip radius of the cutting edge structure produced by the present invention process is desirably in the range of less than about 1 micrometer. The hardness of a polymeric cutting edge structure formed, such as with ORMOCER, may reach near 100 MPa after curing. In the case of SUB, the cutting edge structure may be pyrolised after removing it from the base structure in step 800 of
(41) As shown in
(42) While a conventional razor blade wedge profile is shown in
(43) It should be noted that the base structure 405 of
(44) Once free from the base structure, each cutting edge structure that is produced can generally be assembled individually into a razor cartridge. For example, one or more polymer razor blades may be adhered to blade supports (e.g., with glue, ultrasonic welding) and assembled into razor cartridge housings. Once removed from the base structure, the blades can then be processed or coated if necessary and assembled into a razor cartridge at step 900 of
(45) A razor cartridge 60 having one or more cutting edge structures or razor blades 62 made of polymer 64 of the present invention can be assembled as shown in
(46) While the methods of manufacturing described herein have been referred to with primary reference to a single cutting edge structure (e.g., razor blade), the methods are easily applicable to the manufacture of multiple cutting edge structures simultaneously.
(47) In
(48) Turning to
(49) Assembling the razor cartridge in such a manner eliminates the somewhat time consuming or difficult steps of affixing each individual razor blade to a blade support or to a housing, inserting each blade support-razor blade pair or each blade in the razor cartridge housing, and aligning each separate razor blade to the desired blade height, angle, and spacing. By utilizing the method described herein, the plurality of razor blades are aligned and secured in the blade box, thereby eliminating the need to affix individual blade supports and the difficult process of aligning 3 or more separate razor blades into the razor cartridge housing. While
(50) While the blades illustrated in the figures thus far have generally linear blade edges, other blade shapes and edge patterns can be produced by the methods described herein.
(51) To that end, in a still further alternative embodiment, different cutting structures in addition to straight edged or wedge-shaped configuration for blade edges are also contemplated in the present invention.
(52) These other shapes are produced by using a cutting edge template in step 300a/200b that comprises a different profile. In some instances, a sheet of material or a frame 153 with openings 154 that contain internal cutting edges 152 that are non-linear as shown in the blade box 150 of
(53) Any number of shapes or profiles for the cutting edge template, and hence, for the cutting edge structure or structures that will be formed, is contemplated in the present invention. The present invention includes, but is not limited to, the additional illustrative embodiments depicted in
(54) One of the many advantages of producing razor blades for shaving from polymer in the manner described herein is that resultant cutting edge structures or blade edges formed have very similar surface roughness as the template cutting edge. Thus, when replicating a steel blade, grind marks of the steel template cutting edge are also replicated. Very smooth facet surfaces without grinding marks can be created, if the template is produced from single crystal material such as silicon or sapphire. Accordingly, the resultant cutting edge structure has a similar surface roughness to that of the template cutting edge. A change in the template cutting edge material would change the surface roughness of the resultant cutting edge.
(55) Accordingly, other embodiments are within the scope of the following claims.
(56) The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as 40 mm is intended to mean about 40 mm.
(57) Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.
(58) While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.