Aqueous dispersions

a technology of dispersions and water, applied in the field of water dispersions, can solve the problems of reducing the effective heat resistance, affecting the adhesion of film/foil adhesives, and reducing the viscosity of application, and conventional psas may not have sufficient strength to hold and maintain adhesion on certain substrates

Inactive Publication Date: 2013-03-07
DOW GLOBAL TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The proposed solution enables the formation of strong, durable adhesive bonds on a wide range of substrates, including difficult-to-bond materials, while allowing for low-temperature application and improved resistance to environmental stressors, enhancing their suitability for applications like packaging and optical products.

Problems solved by technology

While adhesive formulations that can be applied at temperatures below 150° C. can be prepared using low molecular weight components or a high wax content, application viscosity and adhesive properties suffer.
While softer or more amorphous components may be added in order to improve adhesion, these components reduce the effective heat resistance.
For a more permanent and highly smooth bond, some conventional PSAs may not necessarily have sufficient strength to hold and maintain their adherence on certain substrates.
Furthermore, conventional PSA when applied to certain materials, may not be able to withstand exposure to elevated temperatures or high humidity.
For example, application of a PSA on acrylic sheets and polycarbonate sheets, known to be “outgassing materials” and difficult to bond, can result in bubbling and delamination.
Certain optical products are exposed to harsh environmental conditions, such as heat, UV (solar) light, water, etc.
The materials may become optically obstructed if the adhesion between the layers is damaged or compromised.

Method used

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  • Aqueous dispersions
  • Aqueous dispersions
  • Aqueous dispersions

Examples

Experimental program
Comparison scheme
Effect test

example hma

and PSA Precursor Dispersion Formulations

example 1

[0145]An aqueous dispersion of a National Starch Cool-Lok 34-2116 Hot Melt Adhesive (HMA), which includes a polymer, wax, and a dispersing agent (and is available from the National Starch & Chemical Company, Berkeley, Calif.) is produced in the following manner:

[0146]The HMA is melted in a hot melt feeder tank set at a temperature of 135° C. The liquid HMA is fed using the hot melter gear pump at a rate of 85 g / min into a heated conduit leading to the mixer. While in the conduit to the mixer, the liquid HMA is injected with 2.8 g / min of Industrene 106 (primarily Oleic Acid). At the mixer (Oakes M-4 4″ rotor-stator operated at 800 RPM) the HMA is combined with 12.35 g / min water and 1.26 g / min of 45% (w / w) KOH solution in water, both of which are pre-heated to about 120° C. before injection into the mixer. In the mixer, an HMA-in-water dispersion is generated.

[0147]After exiting the mixer, 52 g / min of water is pre-heated to 100° C. and added into the dispersion. A 150 PSIG spring-oper...

example 2

[0148]An aqueous dispersion of a H.B. Fuller HM-2055PI HMA (available from H.B. Fuller Company, St. Paul, Minn.), which includes a polymer (polyethylene in this case) and a wax is produced in the following manner:

[0149]The HMA is melted in a hot melt feeder tank set at a temperature of 135° C. The liquid HMA is fed using the hot melter gear pump at a rate of 50 g / min into a heated conduit leading to the mixer. While in the conduit to the mixer, the liquid HMA is injected with 1.8 g / min of Industrene 106 (primarily Oleic Acid). At the mixer (Oakes M-4 4″ rotor-stator operated at 500 RPM) the HMA is combined with 4 g / min water and 0.7 g / min of 45% (w / w) KOH solution in water, both of which are pre-heated to about 120° C. before injection into the mixer. In the mixer, an HMA-in-water dispersion is generated.

[0150]After exiting the mixer, 45 g / min of water is pre-heated to 100° C. and added into the dispersion. A 150 PSIG spring-operated check valve is used at the process outlet to main...

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Abstract

A method and composition for forming an adhesive bond is described. The method includes depositing an aqueous dispersion on a substrate to form a selectively activatable coating, the aqueous dispersion including (A) a polymer capable of forming an adhesive, (B) at least one dispersing agent; and (C) at least one of a tackifying resin, a wax, or an oil wherein the dispersion has at least one of an average particle size of from about 0.1 to about 100 microns and a polydispersity of less than 5; and selectively activating at least a portion of the coated substrate to form the adhesive bond.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority, pursuant to 35 U.S.C. §119(e) to U.S. Provisional Application No. 60 / 697,087, which is incorporated by reference in its entirety.BACKGROUND OF INVENTION[0002]Adhesives are widely used for various commercial applications such as product assembly and packaging. Two specific types of adhesives are known as pressure sensitive adhesives (PSAs) and hot melt adhesives (HMAs). PSAs are a distinct category of adhesive, which, in dry (solvent free) form, are aggressive and permanently tacky at room temperature and adhere to a variety of surfaces without the need of more than pressure. They do not require activation by water, solvent, or heat. In contrast, HMAs are typically applied to a substrate while in its molten state and cooled to harden the adhesive layer.[0003]Most commercially available HMAs require temperatures of 175° C. or greater to ensure complete melting of all the components and also to achieve a sat...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): C09J153/00C09J123/12C09J123/08B32B5/16C09J123/16C09J7/02B05D5/08C09J123/06C09J123/14
CPCC09J5/06C09J201/00Y10T428/254Y10T428/28C08L2666/02C09J123/04C08L23/0869C09J7/20
InventorMAAK, KEVIN D.YALVAC, SELIMLEVINSON, MIKE J.SCHMIDT, DALE C.MONCLA, BRAD MAURICEKALINOWSKI, MATTHEW JAMES
OwnerDOW GLOBAL TECH LLC