# US 11,078,319 B2 · Method for forming a cast elastomer

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- Number: US 11,078,319 B2
- Document ID: US11078319B2
- Status: Granted
- Kind: B2
- Application number: 15/895,971
- Filed: 2018-02-13
- Published: 2018-08-16
- Granted: 2021-08-03
- Earliest claimed: 2017-02-13
- Assignees: Tactus Technology, Inc.
- Applicants: Tactus Technology, Inc.
- Inventors: Justin Virgili; Curtis Takagi
- Web page: https://patentgrep.com/patent/US11078319B2

## CPC

- C08G 18/10: Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
- B05D 1/265: {Extrusion coatings}
- B05D 3/12: by mechanical means
- B05D 7/04: to surfaces of films or sheets (producing layered products by applying coatings of pasty or pulverulent plastics B29C41/00)
- B05D 7/24: for applying particular liquids or other fluent materials
- C08G 18/246: {containing also tin-carbon bonds}
- C08G 18/3206: {aliphatic}
- C08G 18/3237: {aromatic (C08G18/3234 takes precedence)}
- C08G 18/34: Carboxylic acids; Esters thereof with monohydroxyl compounds
- C08G 18/42: Polycondensates having carboxylic or carbonic ester groups in the main chain
- C08G 18/7621: {being toluene diisocyanate including isomer mixtures}
- C08K 5/053: Polyhydroxylic alcohols
- C09D 175/04: Polyurethanes
- G06F 3/016: {Input arrangements with force or tactile feedback as computer generated output to the user}
- G06F 3/041: Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- B05D 1/36: Successively applying liquids or other fluent materials, e.g. without intermediate treatment
- B05D 3/0272: {with ovens}
- B05D 7/542: {the two layers being cured or baked together}
- B05D 2201/02: Polymeric substrate
- B05D 2252/02: of indefinite length
- B05D 2252/04: of definite length in a continuous process
- B05D 2508/00: Polyesters
- G06F 2203/04103: Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

One variation of a method for directly casting a thin layer onto a substrate includes: combining a prepolymer, a solvent, and a curing agent to define a viscous material; advancing a substrate from a roll across a surface continuously at a first speed; depositing the viscous material at a viscosity through a deposition head onto the substrate, the viscous material flowing laterally across the substrate to form a thin layer of substantially uniform thickness over the substrate over a period of time while the substrate advances along the surface; and, at a distance from the deposition head depositing the viscous material onto the substrate corresponding to a duration of time for the viscous material to flow laterally across the substrate, heating the viscous material to evaporate solvent and to induce reaction between the curing agent and the prepolymer to cure the viscous material to form a layer.

## Claims

### Claim 1

A method for directly casting an elastomer film onto a substrate comprising:
combining a first prepolymer, a first solvent, and a first chain extender to define a first material;
advancing a substrate from a first roll across a surface continuously at a first speed;
depositing the first material onto the substrate, the first material flowing laterally across the substrate while the substrate advances along the surface;
after self-levelling of the first material across the substrate to form a first layer of substantially uniform thickness over the substrate, heating the first layer to induce a first reaction between the first chain extender and the first prepolymer and to evaporate the first solvent to cure the first layer exhibiting a first relaxation time in response to impacts;
combining a second prepolymer, a second solvent, and a second chain extender to define a second material, the first layer being soluble in the second solvent;
advancing the substrate and the first layer across the surface continuously at a second speed proportional to a flow rate of the second material;
depositing the second material onto the first layer opposite the substrate, the second material flowing laterally across the substrate first layer while the substrate and the first layer advance along the surface; and
after self-levelling of the second material across the first layer to form a second layer of substantially uniform thickness over the first layer, heating the second layer to induce a second reaction between the second chain extender and the second prepolymer and to evaporate the second solvent to cure the second layer:
comprising physically and chemically cross-linked polymer chains; and
exhibiting a second relaxation time distinct from the first relaxation time and configured to recover from impacts displacing the second layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein combining the first prepolymer, the first solvent, and the first chain extender to define the first material comprises mixing a first solution and a second solution, the first solution comprising the first prepolymer and the first solvent, the second solution comprising a catalyst, a cross-linking agent, and the first chain extender configured to promote polymerization of the first prepolymer and cross-linking of polymer chains to form physically and chemically cross-linked polymer chains that define the first layer.

### Claim 3 (depends on 2)

The method of claim 2, wherein mixing the first solution and the second solution comprises:
mixing the first prepolymer comprising a TDI-terminated polyester prepolymer and the first solvent comprising methyl ethyl ketone to define the first solution; and
mixing the catalyst comprising dibutyltin dilaurate, the first chain extender comprising an aromatic diamine curative for polyurethane, and the cross-linking agent comprising ditrimethylolpropane to define the second solution.

### Claim 4 (depends on 1)

The method of claim 1, wherein depositing the first material onto the substrate comprises depositing the first material onto the substrate translating a first direction during deposition of the first material, the first material distributing across the substrate to form the first layer of substantially uniform thickness extending contiguously across the substrate.

### Claim 5 (depends on 4)

The method of claim 4, wherein depositing the first material onto the substrate comprises depositing the first material onto the substrate comprising polyethylene terephthalate removable from the first layer after curing.

### Claim 6 (depends on 1)

The method of claim 1, wherein heating the first layer to evaporate the first solvent comprises heating the first layer for a first duration to cure the first layer to a first curing level less than a final curing level.

### Claim 7 (depends on 1)

The method of claim 1:
wherein combining the first prepolymer, the first solvent, and the first chain extender comprises mixing the first prepolymer, the first solvent, and the first chain extender within a mixing head;
wherein advancing the substrate across the surface comprises progressing the substrate over a mirror-finish surface toward an oven;
wherein depositing the first material onto the substrate comprises dispensing the first material onto the substrate translating over a mirror-finish surface through a slot die coater; and
wherein heating the first material comprises translating the first layer and the substrate through the oven for a predetermined duration, the oven configured to heat the first layer and the substrate to a target temperature, the predetermined duration defined by a cure time and a target cure level upon exiting the oven.

### Claim 8

A method for directly casting an elastomer film onto a substrate comprising:
combining a first prepolymer, a first solvent, and a first chain extender to define a first material;
while advancing a substrate across a surface:
depositing the first material onto the substrate, the first material flowing laterally across the substrate to form a first layer of substantially uniform thickness over the substrate; and
heating the first layer to:
induce a first reaction between the first chain extender and the first prepolymer;
evaporate the first solvent; and
form a cured first layer exhibiting a first relaxation time;
combining a second prepolymer, a second chain extender, and a second solvent to define a second material; and
while advancing the substrate and the cured first layer across the surface:
depositing the second material onto the cured first layer opposite the substrate, the second material:
flowing laterally across the cured first layer to form a second layer of substantially uniform thickness over the cured first layer; and
dissolving a top portion of the cured first layer due to solubility of the cured first layer in the second solvent; and
heating the cured first layer and the second layer to:
induce a second reaction between the second chain extender and the second prepolymer;
evaporate the second solvent; and
form a cured second layer, the cured second layer exhibiting a second relaxation time greater than the first relaxation time.

### Claim 9

A method for directly casting an elastomer film onto a substrate comprising:
combining a first prepolymer, a first solvent, and a first chain extender to define a first material;
while advancing a substrate across a surface:
depositing the first material onto the substrate, the first material flowing across the substrate to form a first layer over the substrate; and
heating the first layer to form a cured first layer over the substrate exhibiting a first relaxation time;
combining a second prepolymer, a second chain extender, and a second solvent to define a second material; and
while advancing the substrate and the cured first layer across the surface:
depositing the second material onto the cured first layer opposite the substrate, the second material flowing across the cured first layer to form a second layer over the cured first layer; and
heating the cured first layer and the second layer to form a cured second layer, the cured second layer exhibiting a second relaxation time greater than the first relaxation time.

### Claim 10 (depends on 9)

The method of claim 9, wherein combining the first prepolymer, the first solvent, and the first chain extender to define the first material comprises mixing a first solution and a second solution, the first solution comprising the first prepolymer and the first solvent, the second solution comprising a catalyst, a cross-linking agent, and the first chain extender.

### Claim 11 (depends on 10)

The method of claim 10:
wherein heating the first layer to form the cured first layer comprises heating the first layer to a first cure temperature to form the cured first layer; and
wherein mixing the first solution and the second solution comprises mixing the first solution and the second solution, the second solution comprising the cross-linking agent, the first chain extender, and a snap-cure catalyst inactive in catalyzing polymerization of the first prepolymer below the first cure temperature.

### Claim 12 (depends on 10)

The method of claim 10, further comprising:
measuring a first viscosity of the first solution;
measuring a second viscosity of the second solution; and
in response to a deviation of the second viscosity from the first viscosity exceeding a threshold deviation of twenty percent, adding solvent to the second solution.

### Claim 13 (depends on 9)

The method of claim 9, wherein depositing the first material onto the substrate comprises dissolving a top portion of the substrate in the first solvent of the first material.

### Claim 14 (depends on 9)

The method of claim 9:
wherein heating the first layer to form the cured first layer exhibiting the first relaxation time comprises heating the first layer at a first cure temperature to form the cured first layer exhibiting the first relaxation time correlated with the first cure temperature; and
wherein heating the cured first layer and the second layer to form the cured second layer comprises heating the cured first layer and the second layer at a second cure temperature to form the cured second layer, the cured second layer exhibiting the second relaxation time longer than the first relaxation time and correlated with the second cure temperature.

### Claim 15 (depends on 9)

The method of claim 9, further comprising depositing an anti-scratch coating over the cured second layer.

### Claim 16 (depends on 9)

The method of claim 9, further comprising depositing a self-healing protective coating over the cured second layer.

### Claim 17 (depends on 9)

The method of claim 9, further comprising, prior to depositing the first material onto the substrate, heating the first material to reduce a viscosity of the first material to less than 3500 centipoise.

### Claim 18 (depends on 17)

The method of claim 17, further comprising, prior to depositing the second material onto the cured first layer opposite the substrate, heating the second material to reduce a viscosity of the second material to less than 3500 centipoise.