Method of forming a monolayer of particles, and products formed thereby
AssigneeLoctite (R&D) Limited
InventorsCiaran B. McArdle, Joseph Burke, Edward K. Welch, II
Life of this patent
Estimating the term…
Abstract
The present invention provides a number of interrelated methods for the production of random and ordered arrays of particles and recesses as well as films containing such arrays and recesses. The present invention also relates to the random and ordered arrays of particles and films prepared therefrom. The ordered arrays are obtained by the use of ferrofluid compositions which may be curable, solidifiable on non-curing/non-solidifiable. The arrays and films may contain electrically-conductive particles useful in electronic applications for effecting contact between leads or pads.
Claims42
A method of forming a monolayer of substantive particles, said method comprising the steps of:
- (a) applying to a substrate a curable composition having substantive particles contained therein, said substantive particles having a particle size on at least one dimension thereof of at least one micrometer;
- (b) exposing the substantive particle-containing curable composition to a source of energy suitable for effecting polymerization of the curable composition for a sufficient time to effect polymerization of a thin film layer of the curable composition having a thickness of no more than 50% of the height of the largest substantive particles, said thin film layer maintaining the substantive particles in place on the substrate;
- and
- (c) removing uncured curable composition that remains.
A method of forming a monolayer non-random array of substantive particles, said method comprising the steps of:
- (a) applying to a substrate a curable ferrofluid composition, the composition comprising a colloidal suspension of ferromagnetic particles in a non-magnetic carrier liquid, the composition having substantive particles contained therein, said substantive particles having a particle size of at least 1 micrometer, the curable ferrofluid composition applied so as to form a monolayer of substantive particles on the substrate;
- (b) exposing the substantive particle containing ferrofluid composition to a source of energy suitable for effecting polymerization of the curable ferrofluid composition for a sufficient time to effect polymerization of a layer of the curable ferrofluid composition to form a layer of cured composition having a thickness of no more than 50% of the height of the largest substantive particles, while the substantive particles are arrayed in non-random pattern as a result of application of a magnetic field;
- (c) optionally, removing the uncured curable ferrofluid composition;
- (d) applying an adhesive film over the surface of the arrayed substantive particles, opposite to the layer of cured composition;
- (e) optionally, heating the adhesive film;
- (f) pressing the substantive particles into the adhesive film;
- and
- (g) separating the adhesive film with the arrayed substantive particles adhered thereto away from the layer of cured ferrofluid composition;
- and
- (h) optionally, removing any residual cured or uncured ferrofluid composition from the adhesive film or on the substantive particles.
A method of forming a film having a monolayer of particles contained therein, said method comprising the steps of:
- (a) applying to a substrate a curable composition having particles contained therein, said particles having a particle size on at least one dimension thereof of at least 1 micrometer;
- (b) exposing the particle-containing curable composition to a source of energy suitable for effecting polymerization of the curable composition for a sufficient time to effect polymerization of a layer of the curable composition having a thickness of no more than 50% of the height of the largest particles;
- and either
- (I)
- (c) removing the uncured curable composition;
- (d) applying a film-forming material to fill the interstitial spaces between the particles and optionally to cover areas of the substrate flanking the particles to a film thickness similar to that in the particle-containing area;
- (e) optionally, at least partially solidifying the film-forming material;
- and
- (f) optionally, removing the so-formed film from the substrate;
- or
- (II)
- (c) optionally, removing the uncured curable composition;
- (d) applying an adhesive film over the surface of the particles, remote from the layer of cured composition, said film having an adhesiveness with respect to the particles greater than that of the cured composition;
- (e) pressing the adhesive film onto the particles;
- (f) separating the adhesive film with the particles adhering thereto away from the layer of cured composition;
- (g) optionally, removing any substantial amount of uncured or cured curable composition remaining on the adhesive film or on the particles adhered thereto;
- (h) applying a film-forming material to fill the interstitial spaces between the particles and, optionally, to cover areas of the adhesive film flanking the particles to a film thickness similar to that in the particle-containing area;
- (i) optionally, at least partially solidifying the film-forming material;
- and
- (j) optionally, removing the so-formed film from the substrate.
A method of forming a film having a monolayer non-random array of substantive particles therein, said method comprising the steps of:
- (a) applying to a substrate a curable ferrofluid composition, the composition a colloidal suspension of ferromagnetic particles in a non-magnetic carrier liquid, the composition having substantive particles contained therein, said substantive particles having a particle size on at least one dimension thereof of at least 1 micrometer, the curable ferrofluid composition applied so as to form a monolayer of substantive particles;
- (b) exposing the substantive particle containing ferrofluid composition to a source of energy suitable for effecting polymerization of the curable ferrofluid composition for a sufficient time to effect polymerization of a layer of the curable ferrofluid composition having a thickness of no more than 50% of the height of the largest substantive particles, while the substantive particles are arrayed in a non-random pattern as a result of application of a magnetic field;
- and either
- (I) (c) removing the uncured curable ferrofluid composition;
- (d) applying a film-forming material to fill the interstitial spaces between the so-formed array of substantive particles and optionally to cover areas of the substrate flanking the substantive particles to a film thickness similar to that in the substantive particle containing area;
- (e) optionally, at least partially solidifying the film-forming material;
- and
- (f) optionally, removing the so-formed film from the substrate;
- or
- (II ) (c) optionally, removing the uncured curable ferrofluid composition;
- (d) applying an adhesive film over the surface of the arrayed substantive particles, opposite to the layer of cured composition, said film having an adhesiveness with respect to the substantive particles greater than that of the cured composition;
- (e) pressing the adhesive film onto the substantive particles;
- (f) separating the adhesive film with the arrayed substantive particles adhered thereto away from the layer of cured ferrofluid composition;
- (g) optionally, removing any substantial amount of uncured or cured curable ferrofluid composition remaining on the adhesive film or on the substantive particles adhered thereto;
- (h) applying a film-forming material to fill the interstitial spaces in the array of substantive particles and, optionally, to cover areas of the adhesive film flanking the substantive particles to a film thickness similar to that in the substantive particle-containing area;
- and
- (i) optionally, at least partially solidifying the film-forming material.
An article comprising sequential laminae of a first substrate, an adhesive matrix entraining an ordered monolayer array of substantially non-magnetic substantive particles of at least 1 micrometer to 500 micrometers and a second substrate joined to the first substrate by the adhesive matrix, wherein the adhesive matrix is substantially free of ferromagnetic particles smaller than about 1 micrometer.
An article comprising sequential laminae of:
- a first substrate;
- an adhesive matrix substantially free of ferromagnetic particles smaller than about 1 micrometer entraining an ordered monolayer array of substantive particles of at least 1 micrometer to 500 micrometers, the adhesive matrix comprising at least two discrete layers of different adhesive compositions wherein one of said discrete adhesive layers is formed of a thermoplastic adhesive and at least one of said discrete adhesive layers is not thermoplastic;
- and
- a second substrate joined to the first substrate by the adhesive matrix.
An article comprising a support tape substrate, and an ordered monolayer array of transferable substantive particles of at least 1 micrometer to 500 micrometers bound thereto by an adhesive, the adhesive being substantially free of ferromagnetic particles and the adhesive strength of the adhesive being less than the cohesive strength of the particles and being greater to the support tape substrate than to the transferable particles.
An article comprising a support tape substrate, and an ordered monolayer array of transferable substantive particles of at least 1 micrometer to 500 micrometers temporarily bound thereto, the substrate contacting no more than 50% of the surface area of the transferable substantive particles and the adhesive strength of the adhesive being less than the cohesive strength of substantially all of the transferable particles and being greater to the support tape substrate than to the transferable substantive particles.
A method for forming an adhesive film having a regular array of recesses in the surface thereof, the method comprising the steps of:
- (a) applying to a substrate a curable ferrofluid composition containing substantive particles having a particle size on at least one dimension thereof of at least 1 micrometer;
- (b) subjecting the particle-containing curable ferrofluid composition to a magnetic field for a sufficient time to array the substantive particles in a non-random manner in the composition;
- (c) exposing the composition having the particles arrayed therein to a source of energy suitable for effecting polymerization of the curable ferrofluid composition for a sufficient time to effect polymerization of a layer of the curable ferrofluid composition having a thickness of no more than about 50% of the height of the largest substantive particles;
- (d) applying an adhesive film over the surface of the arrayed substantive particles, opposite to the layer of cured composition, said film having an adhesiveness with respect to the particles at least greater than that of the cured composition;
- (e) pressing the adhesive film onto the particles;
- (f) separating the adhesive film with the arrayed substantive particles adhered thereto away from the layer of cured ferrofluid composition;
- (g) applying to the arrayed particles and adhesive film a second adhesive film having an adhesiveness with respect to the substantive particles greater than that of the first adhesive film;
- and
- (h) removing the second adhesive film whereby the first adhesive film has a regular array of recesses on the surface thereof.
Dependencies are inferred from the claim text.