CN113316602A

CN113316602A - Adhesive composition for magnetic flooring systems

Info

Publication number: CN113316602A
Application number: CN201980089185.9A
Authority: CN
Inventors: 彼得·保罗·罗森
Original assignee: Obac Ltd
Current assignee: Obac Ltd
Priority date: 2019-01-29
Filing date: 2019-01-29
Publication date: 2021-08-27
Also published as: ZA202106230B; EP3917986A1; KR20210113984A; WO2020157541A1

Abstract

A liquid adhesive coating composition which cures to a solid form for non-permanently adhering an interior floor or wall covering to a substrate floor or wall surface, respectively, the composition comprising a polymer incorporating iron or other paramagnetic, superparamagnetic, ferromagnetic or ferrimagnetic components which, when cured, permanently adheres to the substrate and, when cured, provides a low tack adhesive surface which is also magnetically attractive on which a magnetized floor or wall covering may be subsequently mounted, said covering including certain types of carpet, linoleum, vinyl materials, wallpaper and other types of magnetically backed coverings. The combination of the low tack adhesion and the magnetic adhesion of the cured composition of the present invention allows the magnetic backed floor or wall covering to adhere sufficiently well to the surface of the cured adhesive composition to remain in place during normal use while maintaining the ability of the covering to be subsequently removed, repositioned, or replaced without damaging the respective covering, adhesive coating composition layer, or substrate.

Description

Adhesive composition for magnetic flooring systems

Technical Field

The present invention relates to magnet and adhesive coating compositions for adhering indoor floor and wall coverings to substrate surfaces, particularly flexible coverings with magnetic backings, which are typically in the form of sheets or rolls, such as certain types of linoleum, vinyl, carpet and wallpaper.

Background

Modern indoor rigid floor coverings evolved from slate, stone, ceramic, clay and other types of sheet material that were loosely or intimately placed or grouted onto a clay or clay substrate, or placed or adhered to a wood or cementitious substrate using cementitious liquids and pastes that dried or otherwise cured into a solid form. These early types of rigid flooring were still in common use. Modern floor adhesives still include these types, but have generally turned to the use of polymers, either alone or in combination with cementitious materials, to adhere rigid floor coverings to corresponding substrate floors. Rigid composite laminate flooring systems have also become very popular in recent years and are a modern example of closely placed interlocking pieces that are typically not adhesively bonded to a substrate floor.

Rigid floor coverings of various types remain important, but not as important as before. Flexible floor coverings now form a large part of the floor market. The evolution of rigid wall coverings is similar to floor coverings, and ceramic sheets often used in kitchens and bathrooms are a common modern example of a rigid wall covering system.

Early crimpable or bendable indoor flexible floor coverings included animal skins, mats or carpets made from plant, animal hair (e.g., wool) and other textiles, fibrous materials, and fabrics made into various woven and non-woven types. There are a wide variety of carpet types and styles that evolve along different paths around the world. Carpets, linoleum, vinyl and flexible laminate flooring, which are now commonly made from synthetic polymers, evolved from earlier types.

Indoor flexible floor coverings are loosely placed or adhered to a substrate using tacks, nails, screws, and/or other types of mechanical fasteners. They can also be adhered to a substrate using a liquid or paste adhesive that dries or otherwise cures into a rigid or flexible (elastomeric) adhesive layer, with or without the use of mechanical fasteners. Cementitious liquids and pastes are not typically used to adhere flexible floor coverings to their respective substrates. Currently, flexible floor coverings employing adhesives include non-cementitious adhesive polymers, often in combination with mechanical fasteners. In the case of carpets and some other floor types, various padding such as flexible foam boards can and often are sandwiched between the carpet and the substrate floor.

Many of the flexible floor coverings described above may also be used as wall coverings. However, the most common type of interior wall covering is paint, and wallpaper is also a very important type. Wall substrates currently in use include stone, brick, concrete blocks and wood panels and older types of plaster, although modern interior wall systems are constructed primarily using gypsum wallboard, which has smooth joints and is receptive to one or more layers of paint, wallpaper or other types of coverings.

Various types of paints, varnishes and other finishes are applied as liquids using a brush, roller or spray, and then dried or otherwise cured to a solid decorative post-coat. Wallpaper is typically adhered using a non-cementitious liquid adhesive that similarly dries or cures into a solid form. Wallpaper is often installed using starch-based adhesives. Vinyl wallpaper, which is peel and stick, may be used, but is less common than conventional wallpaper requiring a separate adhesive layer.

For indoor floors and walls, flexible coverings have historically and now often been used on top of rigid or flexible coverings. For example, the bear skin may be hung on a painted wall or loosely placed on top of a mat or carpet that, in one example of further layering, is installed on a sheet of stone flooring where the sheet of stone has been grouted and adhered to wood or concrete flooring substrates using a cementitious compound.

Flexible covers are typically delivered and installed from rolls, flat strip packs, or baled or boxed sheets.

Paints and other types of coating compounds that are applied in liquid form and dried or cured to a solid form and permanently adhered to a wall substrate are also used on floor substrates, although not as common as their use on walls. In the case of flooring, the most common situation with liquid applied painted or coated flooring is in the commercial and industrial flooring fields, typically on concrete or steel flooring substrates. The bottom of the vessel, often referred to as the deck, is generally covered in this manner.

As is apparent from the above description, it is generally desirable that a floor or wall covering is not permanently adhered to a corresponding floor or wall substrate except in the case where paint is thus generally relatively easy to reapply without removing the earlier paint covering. This is particularly preferred in the case of many flexible cover applications. The need for non-permanent adhesion of the rigid flooring type is less common, although some desire to be able to change rigid flooring sheets to replace damaged flooring sheets or change styles from time to time without having to perform difficult and expensive removal and replacement procedures that often damage or destroy the removed covering, adhesive layer, and/or substrate.

Floor and wall adhesives are generally considered to be permanent, meaning that they are used only once to secure a covering to a corresponding substrate. When the existing cover is removed and a new cover is installed, the adhesive layer is damaged and needs to be replaced. The covering is also usually destroyed and replaced with a new covering. Such removal and replacement typically does not occur with paint. When paint is used as a covering, the existing paint covering is simply painted one or more additional layers of paint on top of the existing paint. While this may indeed happen in some cases, it is not the case with other types of floor or wall coverings. For example, wallpaper may be pasted with another layer on the existing wallpaper, but this is not considered the best method. While more costly and difficult, it is better to peel off the old wallpaper and adhesive layer, and then apply the new adhesive and new wallpaper. Non-permanent adhesives are generally not very effective for use in carpets and other floor or wall coverings because they degrade over time and/or repeated use.

For wall-to-wall carpet installations, it is generally preferred to glue the carpet, especially for large area installations. For vinyl sheet installations, as with most types of sheet flooring, whether flexible or rigid, it is generally believed necessary to adhere the sheet to the substrate using an adhesive. Because large areas are often involved, such adhesives need to be cost effective based on installation cost calculations per unit area. In the case where the adhesive layer needs to be replaced, it is generally considered that the cost is not excessively high.

In recent years, magnetic bonding systems for attaching wall and floor coverings to corresponding wall and floor substrates have gained limited market acceptance. They tend to be quite expensive compared to conventional adhesives. However, the benefits of being able to remove, reposition and/or replace covers without damaging them, the substrate or the magnetically attractive layer of the substrate have shown considerable benefits.

Disclosure of Invention

A liquid adhesive coating composition which cures to a solid form for non-permanent adhesion of an interior floor or wall covering to a substrate floor or wall surface, respectively, said composition comprising a polymer incorporating iron or other paramagnetic, superparamagnetic, ferromagnetic or ferrimagnetic elements which when cured permanently adheres to the substrate and provides a low tack adhesive surface which is also magnetically attractive after adhesion, on which surface a magnetized floor or wall covering may then be mounted, including certain types of carpets, linoleum, vinyl, wallpaper and other types of magnetically backed coverings. The combination of the low tack adhesion and magnetic attractiveness of the cured compositions of the present invention allows the magnetically backed floor or wall covering to adhere sufficiently well to the surface of the cured adhesive composition to remain in place during normal use while maintaining the ability of the covering to be subsequently removed, repositioned, or replaced without damaging the respective covering, cured adhesive coating composition, or substrate.

As further described in the detailed description herein, the combined magnetic attraction and low tack adhesive effect of a repositionable floor or wall covering mounted on a corresponding substrate coated with a composition of the present invention can be altered by altering either or both of the aspects of magnetic attraction and non-permanent chemical adhesion.

The compositions of the present invention include embodiments in which the adhesive compound is cured in the form of an elastomeric foam, which is generated by a secondary chemical reaction when the composition is cured from a liquid to a solid form. The elastomeric foam also combines magnetic attraction with low tack adhesion, as well as additional cushioning and sound damping.

The compositions of the present invention include embodiments wherein the adhesive composition is cured at ambient or elevated temperatures. Exemplary embodiments include adhesive compounds that are applied as liquids to a substrate floor or wall, as well as adhesive compounds that can be manufactured in roll or sheet form, placed on a substrate floor or wall, and then heated to adhere them to the corresponding substrate.

According to a first aspect of the present invention, there is provided a composition comprising magnetic and/or magnetisable particles plasticised by polyurethane and derived from a mixture of:

(a) a first component comprising a polymerizable isocyanate comprising from about 5% to about 20% by weight of the composition; and

(b) a second component comprising:

a glyceride; and

magnetic and/or magnetizable particles, the magnetic and/or magnetizable particles comprising from about 50% to about 90% by weight of the second component, the balance being glycerides.

According to some embodiments, the mixture of components may contain about 11% by weight of isocyanate, the balance being substantially equal, e.g. equal amounts by weight of magnetic and/or magnetizable particles and glycerides.

According to some embodiments, the glycerides may be derived from one or more starting materials of agricultural origin.

According to some embodiments, the glyceride may be castor oil.

According to some embodiments, the isocyanate may be a mixture of 4,4' -diphenylmethane diisocyanate (MDI) and polymethylene polyphenyl isocyanates. According to some embodiments, the MDI may comprise about 30% to 60% by weight of the mixture.

According to some embodiments, the magnetic and/or magnetizable particles may be selected from paramagnetic, superparamagnetic, ferromagnetic and/or ferrimagnetic substances. According to some embodiments, the particles may be selected from: iron, cobalt, nickel, gadolinium, dysprosium, iron-nickel alloys (permalloy), iron (II, III) oxide (magnetite), iron (III) oxide (hematite), ferrosilicon, mixed iron oxides, iron oxides mixed with other metal oxides from the transition element group, such as iron-nickel oxides, or combinations thereof. According to some embodiments, the magnetic and/or magnetizable particles may comprise iron in the form of ferrosilicon containing at least 50% by weight of iron.

According to some embodiments, the composition may further comprise a pigment. According to some embodiments, the pigment may comprise 2% by weight of the first component.

According to some embodiments, the composition may further comprise a desiccant. According to some embodiments, the desiccant may comprise about 1% by weight of the first component. According to some embodiments, the desiccant may be a synthetic zeolite.

According to some embodiments, the composition may further comprise an accelerator to accelerate curing. According to some embodiments, the accelerator may comprise an organometallic compound. According to some embodiments, the organometallic compound may include dioctyltin Dilaurate (DOTL). According to some embodiments, the accelerator may comprise a tertiary amine. According to some embodiments, the tertiary amine may include Dimethylethanolamine (DMEA).

According to a second aspect of the present invention, there is provided a composition comprising iron plasticised with polyurethane and derived from a mixture of:

(a) a first component comprising from about 5 wt% to about 20 wt% of a polymerizable isocyanate; and

(b) a second component comprising a mixture of magnetic and/or magnetizable particles and glycerides, the mixture of magnetic and/or magnetizable particles and glycerides containing in the range of about 50% to about 90% by weight magnetic and/or magnetizable particles, the balance being glycerides.

According to another third aspect of the present invention, there is provided a composition comprising:

(a) a first component comprising a polymerizable isocyanate; and

(b) a second component comprising a mixture of magnetic and/or magnetisable particles and a glyceride.

According to a further fourth aspect of the present invention, there is provided a composition comprising:

(a) a binder; and

(b) magnetic and/or magnetizable particles mixed into the binder, the particles having a smallest diameter of more than 100 nm.

According to some embodiments, the particles may comprise from about 30% to about 80% by weight of the total composition. According to some embodiments, the particles may comprise about 67% by weight of the total composition.

According to some embodiments, the adhesive may comprise an ambient temperature curing adhesive.

According to some embodiments, the adhesive may comprise a moisture curable adhesive.

According to some embodiments, the adhesive may comprise a polymer-based adhesive.

According to some embodiments, the adhesive may comprise a hot melt cured adhesive.

According to some embodiments, the adhesive may comprise a pressure sensitive adhesive.

According to some embodiments, the adhesive may comprise a one-component adhesive. According to some embodiments, the adhesive may comprise a two-component adhesive.

According to some embodiments, the adhesive may comprise polyurethane.

According to some embodiments, the adhesive may comprise an elastomer.

According to some embodiments, the particles are iron-based particles comprising at least 90 wt% iron (Fe), preferably at least 95 wt% iron, preferably 99 wt% iron.

According to some embodiments, the particles are iron-containing ferrosilicon particles comprising 15 to 50 wt.% silicon (Si). The granules may be ferrosilicon containing 85% iron.

According to a fifth aspect of the present invention there is provided a cured composition derived from a mixture comprising:

(a) a first component comprising a polymerizable isocyanate;

(b) a second component comprising a glyceride, and

(c) magnetic and/or magnetizable particles mixed into at least one of the first and second components;

wherein the polymerizable isocyanate comprises from about 10 wt% to about 45 wt% of the cured composition and the magnetic and/or magnetizable particles range from about 30 wt% to about 80 wt% of the cured composition as a whole.

According to some embodiments, the glyceride may comprise castor oil. According to some embodiments, the castor oil may be modified by including about 1 to 2 weight percent of a pigment. According to some embodiments, the castor oil may be modified by including about 0.5 to 1% by weight of a drying agent. According to some embodiments, the castor oil may be modified by including about 0.01 to 1% by weight of a foaming agent. According to some embodiments, the castor oil may be modified by including at least one of an emulsifier and a surfactant. According to some embodiments, the castor oil may be modified by including at least a small amount of a curing agent.

According to some embodiments, the magnetic and/or magnetizable particles may be added to the resulting mixture of the first and second components while the resulting mixture of the first and second components is still in a liquid state.

According to some embodiments, the magnetic and/or magnetizable particles may be added to the second component, and the resulting mixture is then mixed with the first component.

According to some embodiments, the magnetic and/or magnetizable particles may be granular or in the form of powder, flakes or filings or a combination thereof.

According to some embodiments, the magnetic and/or magnetizable particles may be granular or in powder form and have an average diameter between about 10nm to about 500 microns. According to some embodiments, the magnetic and/or magnetizable particles may have an average diameter of more than 100nm and less than about 500 microns.

According to some embodiments, the magnetic and/or magnetizable particles may comprise iron.

According to some embodiments, the magnetic and/or magnetizable particles may comprise iron and/or ferrosilicon, the total iron content of which is at least about 80% by weight.

According to some embodiments, the magnetic and/or magnetizable particles may comprise steel or iron particles encapsulated in a corrosion-resistant coating, the steel or iron particles encapsulated in the corrosion-resistant coating comprising a minimum of about 80% by weight iron.

According to some embodiments, the magnetic and/or magnetizable particles may be selected from paramagnetic, superparamagnetic, ferromagnetic and/or ferrimagnetic substances. According to some embodiments, the particles may be selected from: iron, cobalt, nickel, gadolinium, dysprosium, iron-nickel alloys (permalloy), iron (II, III) oxide (magnetite), iron (III) oxide (hematite), ferrosilicon, mixed iron oxides, iron oxides mixed with other metal oxides from the transition element group, such as iron-nickel oxides, and combinations thereof.

According to a sixth aspect of the present invention there is provided an article comprising a cured composition derived from a mixture comprising the following components:

(b) a second component comprising magnetic and/or magnetizable particles and a glyceride, the magnetic and/or magnetizable particles comprising from about 50% to about 90% by weight of the second component, the balance being a glyceride.

According to some embodiments, the article may be in the form of an elastomeric adhesive. According to some embodiments, the article may be in the form of a floor or wall covering. According to some embodiments, the article may be in the form of a permanent adhesive coating. According to some embodiments, the article may be in the form of a coating of a non-permanent adhesive that is permanently adhered to a substrate.

According to some embodiments, the composition may comprise:

about 177 parts by weight of magnetic and/or magnetizable particles;

about 69 parts by weight castor oil;

about 30 parts by weight of an isocyanate;

about 1 part by weight of a zeolite.

According to some embodiments, the magnetic and/or magnetizable particles may comprise iron and/or ferrosilicon containing 85% iron.

According to some embodiments, the glyceride may comprise castor oil.

The cured composition according to the fifth aspect and/or the article according to the sixth aspect of the invention may be obtained by curing a composition according to the first, second, third or fourth aspect of the invention.

Detailed Description

Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. The terminology includes the words specifically mentioned, derivatives thereof and words of similar import. The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed. The embodiments were chosen and described in order to best explain the principles of the invention, its applications, and practical use, and to enable others of ordinary skill in the art to best utilize the invention.

Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. The same applies to the term "implementation".

As used in this application, the word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion.

Furthermore, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless specified otherwise, or clear from context, "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, if X employs A; b is used as X; or X employs A and B, then "X employs A or B" is satisfied under any of the foregoing circumstances. In addition, the articles "a" and "an" as used in this application and the claims should generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form.

Unless otherwise expressly stated, each numerical value and range should be interpreted as being approximate as if the word "about" or "approximately" preceded the value of the numerical value or range.

It should be understood that the steps of the exemplary methods set forth herein do not necessarily need to be performed in the order described, and the order of the steps of these methods should be understood to be merely exemplary. Likewise, additional steps may be included in such methods, and certain steps may be omitted or combined, in methods consistent with various embodiments of the present invention.

Although the elements of a method claim, if any, are recited in a particular order and provided with corresponding labeling, unless the claim recitations otherwise imply a particular order for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular order.

Without different wording it is understood that in the case of referring to percentages (%) of components in the composition, this refers to weight percentages, i.e. the weight of the components in the total weight of the composition in which the particles are then located, expressed as percentages.

The prior art is replete with elastomeric adhesives including silicones, latexes and other types of rubber-based latexes, elastomeric polyurethanes, and the like.

It would be a rather cumbersome and exhaustive task to attempt to list or describe in any detailed quantity, in its entirety, many suitable substances that can be effectively combined with magnetic and/or magnetizable particles. The preferred method employed here to make it a more manageable task is to narrow down to the current most preferred by focusing on certain preferred attributes.

Broadly, the compositions of the present invention comprise a polymeric binder having dispersed throughout magnetic and/or magnetizable particles, which polymeric binder permanently adheres to a substrate when the binder is cured to a solid form. The cured composition has relatively high elasticity and the exposed surface of the cured composition has low tack adhesion.

Exemplary elastomeric adhesive coating compositions of the present invention may be in a one-component or two-component configuration (also referred to as a two-part configuration or two-part composition) in which the magnetic and/or magnetizable particles are incorporated into one or both of the components, or, in the alternative, can be added and incorporated into one of the components in the field and then the other component, or, in the alternative, can be added in the field and incorporated after the two components are first mixed together.

Exemplary embodiments of the elastomeric adhesive coating composition have a sufficiently low viscosity in both respective components such that a maximum amount of magnetic and/or magnetizable particles can be incorporated into the composition of the invention while keeping the effort required to mix the components together at a dynamic viscosity of less than about 250cPs at about 25 degrees celsius or about 77 degrees fahrenheit (prior to addition of the magnetic and/or magnetizable particles) to a minimum. The incorporation of the magnetic and/or magnetizable particles can be carried out using a simple hand tool, for example a stirring rod or an electric drill with mixing paddles. Industrial paint shakers or other cumbersome or expensive equipment are not required and should not be used to mix the compositions in field applications.

Although moisture curing adhesives may be used within the scope of the present invention, exemplary embodiments of the composition do not rely on atmospheric moisture for curing. Exemplary embodiments of the present invention also include liquid or solid one-component binders having magnetic and/or magnetizable particles incorporated into the binder. While one-part solvent-based, latex and acrylic liquid compositions are less desirable than two-part liquid compositions, such one-part adhesives are within the scope of the present invention, although it may not be convenient to mix the two-part compositions in the correct proportions.

Exemplary embodiments include non-liquid or solid adhesive compounds, which are adhesive compounds having magnetic and/or magnetizable particles incorporated into an adhesive, which may be manufactured in solid form, such as a roll or sheet, placed on a substrate floor or wall, and then heated or pressed to adhere them to the corresponding substrate floor or wall. Such adhesives may be hot melt adhesives or have pressure sensitive adhesive aspects, respectively. Hot melt adhesives are solid and have good strength at temperatures below about 50 degrees celsius (about 120 degrees fahrenheit) and typically melt at temperatures above about 200 degrees celsius (about 400 degrees fahrenheit). Such adhesives begin to re-cure at temperatures below about 150 degrees celsius (about 300 degrees fahrenheit).

Moisture-curing one-component adhesives typically cure slowly and there is no mechanism to control the rate of cure during application. The rate of cure also depends on ambient temperature and humidity. Air-drying adhesives typically contain solvents to control the curing process. Thus, for such air-drying adhesives, the rate of cure depends on temperature and humidity. While two-part adhesives are contemplated as the preferred adhesive component of the present invention, the present invention is intended to encompass single-part adhesives, including those discussed above, in which the two components of the adhesive described in detail below are replaced by a single-part adhesive.

For environmental reasons, the elimination of solvents, which are generally considered undesirable, is becoming a more important consideration, especially in the case of indoor applications. Latex, vinyl, and acrylic adhesives are very popular, although once cured, they tend to have shorter lifetimes and less moisture resistance than exemplary two-component systems. The magnetic and/or magnetisable particles may be pre-mixed into these components or mixed into the composition in situ.

Minimizing cost is a key driver, which is normal for bringing commercial products to market. Conversely, it is advantageous to maximize the storage or shelf life of the unmixed components to at least one year, preferably to ten years or more. The unmixed components of the exemplary embodiments of the present invention are expected to have a long shelf or shelf life.

Another driving factor is the shift to renewable ingredients and the ability to produce compositions in the most sustainable manner.

In recent years, there have been LEEDS, for example^TMThe benefits of authentication, which are becoming increasingly important for residential and commercial construction projects.

Open time, working time or pot life, defined as the time after mixing during which the mixed composition can be applied before the composition cures to such an extent that the composition is no longer useable, is typically in the range of 10 to 30 minutes, and fully cures within about 24 hours (to at least 90% of the final hardness). Exemplary embodiments of the present invention may optionally include the use of curing additives for setting both the cure rate, open time, and full cure time.

For a two-part "unit" per package, the package volume can be maintained in a mixed volume range of 2 to 15 liters (0.5 to 4 U.S. gallons), with the unit weight (including magnetic and/or magnetizable particles) maintained below the maximum weight one can safely handle for all manual applications, less than 45kg (100 pounds). The maximum weight includes the addition of magnetic and/or magnetizable particles. One notable exception is in the case of large spray systems where the components can also be packaged in large quantities.

Two-part urethane (polyurethane) adhesives are well known and widely used as structural adhesives. In general, polyurethane adhesives are generally selected for their superior flexibility, bond strength, shock and impact resistance, durability, chemical inertness, and other desirable properties as compared to other classes of adhesives. Such adhesives typically consist of two components, one of which contains an isocyanate-terminated compound having at least two reactive isocyanate groups and the second component contains a hydroxyl-terminated compound having at least two reactive hydroxyl groups.

Most prior art adhesives, including those described above, are permanent adhesives, meaning that once applied and cured, the adhesive cannot be reused. Attempts to reposition articles attached with permanent adhesives often result in damage or destruction of the adhesive and the attached article.

Pressure sensitive adhesives are adhesives that adhere when pressure is applied to join the adhesive to an adherend. No solvent, water or heat is required to activate the adhesive. Most pressure sensitive adhesives are also of the permanent type, but such adhesives include many non-permanent adhesives that are capable of retaining their adhesiveness very sufficiently so that an article such as a tape strip can be reapplied or repositioned. Such non-permanent or repositionable adhesives form a relatively small subset of the general class of adhesives.

Some adhesives are intended to exhibit different adhesion at different times. For example, it is known in the art that certain compositions can be partially cured in a rapid manner at room temperature under atmospheric conditions to give partially cured compositions in a few minutes that exhibit properties similar to those of pressure sensitive adhesives having excellent tack, shear and peel strength. In such adhesives, development of full strength proceeds over a longer time frame. When a composition comprising a blocked isocyanate prepolymer obtained by reacting a poly (alkylene oxide) polyol and a diol or triol with a diisocyanate in an equivalent ratio of two isocyanate groups per hydroxyl group and then blocking the remaining isocyanate groups with a phenolic blocking agent such as phenol is mixed with a polyamine, a flexible structural adhesive composition is obtained which exhibits a long open time with excellent tack and peel strength before complete gelling or curing.

Exemplary pressure sensitive adhesives comprise the reaction product of at least one alkyl acrylate liquid polymer containing terminal and random hydroxyl functionality, and a prepolymer of at least one polyester diol or polyalkylene ether glycol with an excess of an aromatic diisocyanate. Such adhesives have desirable properties including excellent rolling ball tack, peel adhesion, and shear adhesion. However, such adhesives tend to be permanent adhesives.

Repositionable or non-permanent adhesives of interest include the following exemplary adhesives: comprising tacky elastomeric copolymer hollow or solid microspheres and an adhesive copolymer containing a macromer. These adhesives may also comprise at least one acrylate. These microsphere-type repositionable adhesives tend to be quite expensive compared to other pressure sensitive adhesives known in the art.

Combining magnetic and/or magnetizable particles with any such binder produces interesting and useful embodiments of the invention, but there are other embodiments, which also tend to be less costly, made from two-component polyurethane binders with more of the preferred attributes described earlier in this specification. Specific examples of exemplary embodiments of the invention are provided below with respect to, among other things, chemical composition, desirable and/or advantageous properties and related characteristics.

Example 1

In the two-part low viscosity polyurethane adhesive coating compounds of the present invention, the first component of the adhesive of the present invention is a polymerizable isocyanate including any isocyanate known in the polyurethane art to polymerize with hydroxyl containing compounds. Exemplary isocyanates are those containing 4,4' -diphenylmethane diisocyanate (MDI) alone or in combination with its 2,2' -isomer, 2, -4' -isomer and/or polymethylene polyphenyl isocyanate. In an exemplary embodiment, the MDI comprises from about 30% to about 60% by weight of the combination. Currently manufactured by the Dow chemical company under the name of PAPI-27^TMThe products of (a) are exemplary polymerizable isocyanates. This combination of isocyanates is commonly referred to in the art as "polymeric MDI". It is also generally classified as aromatic in type, generally more expensive than various aliphatic type isocyanates known in the art but with some desirable characteristics, such as a greatly reduced possibility of changing color upon exposure to ultraviolet radiation.

The second component of this two-part low viscosity polyurethane adhesive coating compound comprises a specific class of polyols known as glycerides or acylglycerols, which are esters formed between glycerol and one or more fatty acids. Glycerides are commonly found in vegetable oils and animal fats. In some cases, glycerides can also be produced synthetically from a range of starting materials. In an exemplary embodiment, the glyceride is a vegetable oil. In a further exemplary embodiment, the glyceride is castor oil. Castor oil is a natural and renewable product, a triglyceride of fatty acids containing an average of 2.7 secondary OH groups per molecule, the fatty acid being mainly ricinoleic acid. This includes some preferred modified polyols or glycerides, which will be described in detail below, and will be referred to herein as "modified castor oil".

The ratio of second component to first component in the example 1 mixture, prior to inclusion of the magnetic and/or magnetizable particles, where the first component was the polymeric MDI described above and the second component was the first and second components of the modified castor oil described above and in the subsequent paragraphs, was 70:30 parts by weight or 3:1 parts by volume. This is a deliberately derived set of ratios because the probability ratios are easier to measure in the field, especially by volume, than the fractional ratios. Standard mixing drums used in the coatings and paints industry are typically pre-printed with indicia showing, for example, 1:1, 2:1, 3:1 and 4:1 volume ratios.

A 3:1 volume ratio is preferred because there is sufficient liquid volume in the second component (modified castor oil in this example 1) to accommodate a large number of magnetic and/or magnetizable particles in the mixture (as will be described in detail in the later part of this specification), where these particles are pre-mixed into the second component at the factory, mixed into the second component on site, or mixed into a mixture of the first and second components. However, despite the stated preferred features, a wide range of ratios is possible, actually ranging from 1:1 to 4:1 (by volume), and they need not be approximate or integer increments. The pre-polymerization of some castor oil or other ingredients into the first component, including the addition of varying amounts of active or inert ingredients to the first component or the second component or both, is among the techniques that can be used to adjust the two-component formulation to meet the particular volume and/or weight ratio of the components. There are many methods known in the art because many two-component formulations need to be designed to specific ratios to match the equipment design that is typically set to specific volume ratios, the most common being 1:1, 1.5:1, 2:1, 3:1 and 4:1 parts by volume or PBV.

The magnetic and/or magnetizable particles used in the composition of the invention are preferably added to the castor oil component in example 1 for a variety of reasons. First, it is considered a good practice not to add anything to the isocyanate component, as it is more reactive and easily contaminated than the castor oil component. The isocyanate component is typically packaged in a sealed container with a blanket of nitrogen gas, the non-reactive nitrogen gas displacing any atmospheric moisture or oxygen. Second, the castor oil component, which is primarily an oil, more readily incorporates magnetic and/or magnetizable particles therein and produces a smoother and more easily stirred mixture. Designing the composition with a relatively large oil component makes it relatively easy to mix all the desired magnetic and/or magnetizable particles into the binder coating compound of the invention without increasing the viscosity too much. Third, the incorporation of magnetic and/or magnetizable particles into the second component does not initiate any chemical reaction. This is advantageous because one can spend as much time as necessary mixing the magnetic and/or magnetizable particles until they are sufficiently dispersed without consuming any working time (pot life). If the magnetic and/or magnetisable particles are subsequently added to the mixture of the first and second components, the time taken to mix and dispense the magnetic and/or magnetisable particles correspondingly reduces the remaining working time, since the mixture of the first and second components immediately starts to react when they come into contact with each other. After the magnetic and/or magnetizable particles have been dispersed in the second component, it takes relatively little time to mix in the first component.

Historically, the price and supply of castor oil has proven to be quite variable. Thus, ring-opening products of epoxidized fatty acid esters with fatty alcohols having a functionality of 1 to 10 can be used. Renewable starting materials include: epoxidized soybean oil with an epoxy value of 5.8 to 6.5, epoxidized sunflower oil with an epoxy value of 5.6 to 6.6, epoxidized linseed oil with an epoxy value of 8.2 to 8.6 and epoxidized whale oil with an epoxy value of 6.3 to 6.7. The epoxidized triglycerides can be fully or even partially ring opened with polyols or monohydric alcohols. Partial ring opening results in the formation of modified triglycerides containing, on average, epoxides and hydroxyl groups, as well as other groups. This subset of ring-opening products of epoxidized triglycerides includes compounds that are readily available and can be produced in a variety of variations.

Various epoxidized triglycerides of agricultural origin (in other words, of vegetable or animal origin) can be used as starting materials for the production of ring-opened products, the main requirement being that a large proportion of the epoxide groups should be present. For example, epoxidized triglycerides containing from about 2 wt.% to about 10 wt.% epoxide oxygen are suitable. Products having an epoxide oxygen content of between about 3% and about 5% by weight are particularly suitable for certain applications. The epoxide oxygen content can be adjusted by starting from triglycerides with relatively low iodine values and fully epoxidizing them or by starting from triglycerides with high iodine values and only partially reacting them to form epoxides.

Another group of products suitable for adhesive applications are based on epoxidized triglycerides having an epoxide oxygen content of between about 4% and about 8.5%. Products such as this may also be produced from the following fats and oils (in order of increasing initial iodine value): tallow, palm oil, lard, castor oil, peanut oil, rapeseed oil and cottonseed oil.

Some relatively simple modifications to the crude oil, sometimes after filtering out any remaining solids, are made to produce a particularly preferred embodiment of the invention, starting from crude castor oil which is generally classified in the art as crude oil No. 1. Such modifications may include the optional addition of pigments such as titanium dioxide (white) and black iron oxide in amounts of about 2% by weight. Black iron oxide is also magnetic, but at this amount as small as 2%, its level is insignificant. The oil needs to be free of moisture, which can be achieved by heating, adding a desiccant, such as synthetic zeolite, in an amount of about 1 wt%, or heating followed by both such additions to remove excess moisture.

In certain exemplary embodiments, a foaming or blowing agent may be incorporated. These blowing or blowing agents react with isocyanates to form carbon dioxide. Small amounts of water, or alcohol, may be added. Various blowing agents may be used alone or in combination to produce different amounts and amounts of foam upon curing. Thus, cell size and structure (closed cell, open cell, size distribution, etc.) can be affected.

Surfactants and/or emulsifiers may also be used to modify the castor oil.

Plasticizers such as plasticizing oils may optionally be added. Solvents may also be used. Conductive materials may be added, although many of the preferred magnetic and/or magnetizable particles are conductive. Metallic and/or non-metallic flakes may be added to achieve a visual effect. Materials resistant to the effects of ultraviolet radiation and antioxidants may also be incorporated.

Other materials may be included such as abrasives, carbonate or boron components or other additives to enhance fire resistance. Additives for improving absorption resistance, cellulose or glass fibers for reinforcing strength, and various fillers may also be used. Toxins and antimicrobial additives may be added to prevent bacterial growth or other forms of fouling.

Although the example 1 composition of the present invention will cure to at least about 90% of the final hardness in about 24 to 36 hours at ambient temperature, in one exemplary embodiment, an accelerator may be added to the composition to accelerate the cure in each case. These accelerators include tertiary amines, such as Dimethylethanolamine (DMEA), or organometallic compounds, such as dibutyltin Dilaurate (DBTL) or dioctyltin Dilaurate (DOTL). Various accelerators may be used alone or in combination to achieve different cure rates during different portions of the cure cycle. Such accelerators may also be selected to bias or preferentially cure different aspects at different rates. For example, some accelerators accelerate primary curing without accelerating secondary foaming reactions and vice versa.

Exemplary magnetic and/or magnetizable particles are selected from paramagnetic, superparamagnetic, ferromagnetic and/or ferrimagnetic substances, in particular from: iron, cobalt, nickel, gadolinium, dysprosium, iron-nickel alloys (permalloy), iron (II, III) oxide (magnetite), iron (III) oxide (hematite), ferrosilicon, mixed iron oxides, iron oxides mixed with other metal oxides from the transition element group, such as iron-nickel oxides, and combinations thereof.

The magnetic or magnetisable particles are granular or in the form of powder, flakes or filings or a combination thereof. Preferred particles are granular or in powder form and have an average diameter of from about 100nm to 1000 microns, especially from about 1 micron to about 350 microns. Lower threshold diameters greater than about 100nm are selected due to viscosity limitations, improved magnetic properties, and current cost considerations.

Particles smaller than 100nm tend to increase viscosity too quickly to incorporate enough particles to obtain a sufficient density of magnetic and/or magnetizable particles in the cured adhesive coating composition of the invention to meet the minimum magnetic attraction requirements for floor or wall coverings. It is well known that for many magnetic and/or magnetizable materials, coarser particles having larger particle sizes generally provide increased permeability, which is an advantage of using larger particle sizes. The current cost of larger particle sizes also tends to decrease, but this trend may change.

Exemplary magnetic or magnetizable particles include steel or iron having iron contents of up to about 99% by weight, such as steel and iron powder used in powder metallurgy and powder forging applications. However, despite the ability of the polymer compositions of the present invention to disperse them therein to encapsulate them, these particles are very susceptible to staining.

For certain applications, particularly where high or potentially high moisture levels are of concern, the following magnetic and/or magnetisable particles may be used: it consists of steel particles or iron particles encapsulated in silica or other corrosion-resistant coating and contains a minimum of about 80% iron, although the associated costs are generally higher compared to powdered or granular iron or steel.

The magnetic ferrosilicon has a certain corrosion resistance. Magnetic ferrosilicon is typically produced in an electric arc furnace and typical grades contain about 15% to about 50% silicon. Silicon inhibits oxidation of the iron so that the particles do not rust. Another form of magnetic ferrosilicon is one that has been atomized to a more spherical form than conventional comminuted and ground forms. This atomized form tends to mix more easily into the polymer. It may be beneficial to keep the iron content of ferrosilicon relatively high, with a particularly preferred grade containing about 85% iron (about 15% silicon).

When these above-described exemplary iron-based magnetic and/or magnetizable particles are used, the polymer typically comprises from about 1/4 to 1/2 by total weight of the composition, while the iron-based magnetic and/or magnetizable particles comprise the remainder 1/2 to 3/4 by weight of the inventive composition. In the embodiment of example 1, the iron-based magnetic and/or magnetizable particles comprise iron and/or 85% iron grade ferrosilicon and comprise about 2/3 by weight of the composition.

The composition of the present invention provides an adhesive floor or wall surface whose adhesive effect is a combination of magnetic attraction superimposed on or combined with a low tack adhesive effect and a surprisingly enhanced shear adhesion effect in the horizontal plane (in the case of a floor) and in the vertical plane (in the case of a vertical surface such as a wall). The tensile adhesion in the case of a floor is a measurement of the vertical tensile force.

Although the following description is based on measurements made in the case of floor applications, the description is also applicable to walls.

The method of determining the vertical (tensile) adhesion to the floor is performed by measuring the force per unit area required to pull (to separate) the magnetic floor covering vertically from the cured surface of the composition of the present invention. It is a measurement well known in the art of coatings or coverings as a measure of pull-off strength. In the context of the present invention, to determine the horizontal (shear) adhesion of a floor covering, the force per unit area required to pull horizontally (until there is a visible horizontal displacement or movement) the magnetic floor covering from a cured surface coating comprising the adhesive composition of the present invention is measured. Shear measurements are particularly important for flexible floor coverings. If insufficient shear adhesion is present, the carpet, sheet, web vinyl, etc. tends to shift and wrinkle, bunch, pop up and overlap, or otherwise move in an undesirable manner. While pull-off strength is often measured and compared, shear strength may be a characteristic that is often more important but less often measured. For extreme examples illustrating the importance of high shear strength relative to pull-off strength, the tendency of a load-carrying forklift to lift the floor covering is much less than the tendency to cause the floor covering to move horizontally when a brake or acceleration is rapidly applied. A less dramatic but more common problem is that in high traffic situations, the carpet may move horizontally in small increments with each passing person. These cumulative movements can result in relatively large horizontal motions. The carpet is typically pre-stretched and held tightly at the edges to maintain its orientation during installation so that any slight incremental movement caused by traffic or other causes will return to its original shape after each passage of a person or other movement. In cases with relatively high shear resistance, such as when floor coverings are used with various embodiments of the adhesive coating composition of the invention, little or no pre-stretching of the floor covering is required.

For the tensile pull-off strength test, a 2 inch by 2 inch (50.8mm by 50.8mm) square magnetic floor sheet can be used. For the shear test, square magnetic floor sheets of 18 inches by 18 inches (457mm by 457mm) can be used. The floor sheets used for this test included increasingly widely used samples of the type of flexible floor sheet, commonly referred to as "LVT" or "luxury vinyl sheet", having a magnetic backing. This 2 inch by 2 inch magnetic backing LVT has a mass of 15g and due to its mass, exerts a force of about 0.15 newtons (about 0.03 pounds force) downward. The larger 18 inch by 18 inch square magnetic backing LVT has a 1.42kg mass, due to which about 14N (about 3 pounds force) is applied downward. The LVT thicknesses were each about 3mm (0.125 inch or 1/8 inch).

The tensile and shear measurements performed on various embodiments of the inventive composition may be compared to cured epoxy, polyurea, polyurethane, polyaspartic acid, and/or other coatings without any adhesive tack.

Comparative example

Polyaspartic acid (polyurea) two-part aspartate polyurea (AE-PUREA) compositions were used to produce comparative (non-tacky) compositions, hereinafter "comparative", containing magnetic and/or magnetizable particles consisting of a Ferrosilicon cyclic 60 alloyed Ferrosilicon 15% containing about 85% iron, available from M & M Alloys, with a ratio of part a to part B of 1.35:1 parts by volume or 100:79 parts by weight, with a typical batch containing about 4.5kg (about 10 pounds) of Ferrosilicon mixed into about 2.35 liters of AE-PUREA. Reference non-tacky magnetic and/or magnetizable floor coatings of the prior art were prepared at a thickness of about 0.5mm (0.020 inches) by curing the comparative example composition. The final hardness of the cured comparative composition was greater than about shore D55.

Example 2

Another embodiment of the magnetic and/or magnetizable binder coating composition of the invention, which is a more narrowly specified exemplary embodiment of example 1 and is hereinafter referred to as example 2, comprises a mixture of: 177 parts by weight of magnetic and/or magnetizable particles in the form of atomized ferrosilicon, containing about 85% iron, as used in the comparative examples; 70 parts by weight of modified castor oil; and 30 parts by weight of polymeric MDI, which is cured to a thickness of about 0.5mm (about 0.020 inches). The final hardness of the cured example 2 composition was less than about shore D45.

The vertical tensile and horizontal shear tests performed on the cured composition of this example 2 were compared to the same tests performed on the cured composition of the comparative example. The test results revealed that shear enhancement was disproportionately high compared to the vertical tensile pull-off test results. The type and amount of magnetic and/or magnetizable particles, and the density of particles per unit area, are approximately the same.

Some vertical pull-off test results were about 120g (about 1.2 newtons or about 0.26 pounds force) for the example 2 embodiment and about 90g (about 0.9N or about 0.2 pounds) for the comparative example (measured at 5 minutes in both cases). The vertical tensile test result of example 2 was calculated and found to be 33% higher than that of the comparative example. The difference in vertical pull test results is due to the additional low tack adhesion, since the magnetic attraction of the two is about the same.

For additional comparison, tensile pull-off strength test results for comparative examples and example 2 were 0g (0 newtons or 0 pounds force) and 20g (about 0.2 newtons or about 0.05 pounds force), respectively, when installed without the inclusion of magnetic and/or magnetizable particles. The difference is due entirely to the adhesive tack properties of example 2, whereas in the comparative example there is no adhesive tack properties at all.

The horizontal shear test of example 2 resulted in about 10kg (about 98 newtons or about 22 pounds force) versus about 7kg (about 69 newtons or about 15 pounds force) for the comparative example, with a 50% difference measured in less than 30 seconds, respectively. The horizontal shear test was also conducted at 5 minutes, with results of about 15kg (about 147 newtons or about 33 pounds) being obtained for example 2, and about 11kg (about 108 newtons or about 24 pounds) being obtained for the comparative example, with a difference of 40%. It is also worth noting that the magnetic attraction increases over time due to the nature of the magnetic material. When subjected to a strong magnetic field, magnetic materials tend to align magnetically, becoming more magnetically attractive.

While the low tack adhesive properties increased the tensile pull off value by about 30% to 40% compared to the non-tacky comparative examples, the corresponding horizontal shear strength increased by about 40% to 50%. Without intending to be bound by a particular theory, this unexpected disproportionate high shear test result is a desirable result, which appears to be caused by the magnetic attraction of the floor covering pressing down on the binder compound of the invention and increasing the frictional resistance as part of the magnetic attraction. This may be due to the hardness of the preferred compositions of the present invention (below shore D45) being lower than the hardness of the harder, non-stick comparative magnetic coating compositions, which appear to generally have higher hardness values (above shore D50, more commonly about shore D60 to shore D85). The additional properties of the low tack adhesive as a softer material appear to allow the floor covering to be pulled down and somehow more tightly "dig" into the cured adhesive than harder prior art coating materials. This magnetic pulling action also serves to prevent dust and other contaminants from entering under the cover and contaminating the system during normal use, thereby avoiding premature reduction or elimination of the low tack adhesive effect. As previously mentioned, low tack adhesives generally do not work well for floor coverings because such adhesives are too easily contaminated and lose their adhesion too easily. The magnetic attraction is largely unaffected by dust or other contaminants that enter between the cover and the magnetic adhesive coating.

In addition, the relative softness may contribute to shear resistance by allowing localized defects (ridges or raised portions of the adhesive coating) to become somewhat flattened and/or compressed, thereby increasing the actual physical contact area between the coverstock and the adhesive coating as compared to harder, less compressible coatings. Even a slight increase in contact area allows the low-tack adhesive to become more effective.

For additional comparison, the horizontal shear strength test results for comparative examples and example 2 were 0kg (0 newtons or 0 pounds force) and less than 2kg (about 20 newtons or about 5 pounds force), respectively, when installed without the inclusion of magnetic and/or magnetizable particles. The difference is due entirely to the adhesive tack properties of example 2, whereas in the comparative example there is no adhesive tack properties at all. Interestingly, the isolated low tack adhesive properties (in terms of non-magnetic attraction) are somewhat less than expected. This seems to be consistent with the above theory that without magnetic attraction, the sheet is more easily separated or "popped" from the adhesive coating, as the absence of a constant magnetic force during testing increases the friction between the LVT covering and the adhesive coating. The performance on the isolated low tack adhesive is not as good at all as when operating in conjunction with the magnetic attraction aspect. This is an unexpected result. It is expected that these two effects are simply added, rather than multiplied as the measurements reveal.

About 2.5 liters of the example 2 embodiment mixture and a similar amount of comparative reference readily enable easy incorporation of iron powder (about 99% iron in the sample used, with a maximum particle size of about 250 microns) or atomized ferrosilicon (about 85% iron in the sample used, with a maximum particle size of about 150 microns) having a median particle size in the range of about 1 to 100 microns, respectively, of about 4.5kg (about 10 pounds) at ambient temperature, or a median particle size average smaller but still in the same range of about 1 to 100 microns. This can be done mechanically using a drill with a paddle, by other mechanical means, or manually using a simple wood, plastic or metal stir bar, with mixing times not exceeding a few minutes. Such amounts provide an adhesive coating of about 0.5mm (or about 0.020 inches or about 20 mils) thickness at a coverage of about 6.5 square meters or about 70 square feet with sufficient magnetic attraction between the floor covering and the substrate floor or wall coated with the cured adhesive coating composition. The actual minimum threshold magnetic attraction using the horizontal shear strength test procedure described above is about 10kg (about 98 newtons or about 22 pounds force) when the test is conducted about 5 minutes after the start of the test. Attempt to agitate a similar amount of primary particle sizeMagnetite-Iron Oxide powder (Huntsman-Davis Colors-860 Synthetic Iron Oxide Black) of 0.20 micron or 200nm^TM) Without success because the viscosity increased too much, too quickly. Only about half the amount or about 2.5kg (about 5 pounds) is the total amount that can be easily hand stirred at ambient temperature. This is generally found to be less than a satisfactory amount of magnetic and/or magnetizable magnetite iron oxide particles, as such concentrations generally do not provide sufficient magnetic attraction to hold the floor sheet in place. In this case, the horizontal shear test result measures about 5kg (about 49 newtons or about 11 pounds force). However, the use of elevated temperatures and mechanical mixing in the form of a high viscosity paste to make a flake form of the binder composition of the present invention can include a substantial amount of dry magnetic and/or magnetizable particles, such as the magnetite iron oxide particles described herein in this example, in the mixture. Similarly, the density of other magnetic and/or magnetizable particles in the various compositions of the invention may be increased in this way.

It is another feature of the present invention that both the combined total and relative amounts of adhesion caused by the magnetic attraction and the low tack adhesive can be varied and adjusted to achieve a net effective adhesion that meets the specific needs of a particular application while optimizing cost aspects.

Changing the low tack adhesive properties is very inexpensive, as it can be done as follows: for example, in the case of example 2, slightly increasing the ratio of the second component to the first component from about 70:30 parts by weight to 72:28 produced slightly softer and more tacky results. Changing the ratio to 68:32 in the other direction will produce a stiffer and less viscous result. The amount of magnetic and/or magnetizable particles used in the composition can be increased by incorporating more and/or increasing the mounting thickness in the composition, thereby changing the magnetic attraction. Selecting a magnetic and/or magnetizable material with higher magnetic properties is another option, but is generally more costly. Increasing the relative amount of magnetic material or the mass of these materials is often expensive. The magnetic attraction can also be increased by enhancing the magnetic properties of the magnetic backing of a carpet, sheet or other floor or wall covering by one or more of a variety of known means, which also tend to be more expensive than adjusting the adhesive coating composition formulation.

Exemplary embodiments of the composition have good self-leveling properties when used in flooring applications and sag resistance when used in wall applications. The tack is low enough that the person installing the floor covering is able to walk on the surface of the cured composition without their footwear becoming so sticky that these persons are unable to walk freely enough to install the floor covering without being worn with spiked shoes or other specialized feet.

Exemplary thicknesses for exemplary embodiments of the cured composition are about 0.50mm (about 0.020 inches), with thicknesses ranging between about 0.20mm to about 8mm (about 0.008 inches to about 0.30 inches). In the case of flooring applications for exemplary embodiments of the compositions, the good self-leveling properties allow the compositions to fill cracks, voids, depressions, and low points in imperfect flooring substrates. Substrates may include, but are not limited to, concrete and/or other cementitious materials, wood, composite materials, and metallic materials.

The field test of the embodiment of example 2 compared to the comparative example shows that the filling of voids and the like is improved due to the better self-leveling property compared to the embodiment of comparative example. Low spots or voids are highly undesirable under LVT floor sheets and other floor coverings, as are ridges, raised areas and/or ridges. Such high points are typically mechanically removed using a grinder and/or other means known in the art. Use in the presence of voids under floor coverings such as LVTs can result in the sheet beginning to crack and fail, especially in high traffic areas. Such failures are a big problem in applications such as supermarket floors, where various trolleys and other wheeled devices carrying loads are often used. The wheels (and the shoe heel) tend to quickly cause such depressions or voids under the floor sheet to be revealed by the deformation of the sheet. Such deformation often leads to sheet failure. Removing any ridges prior to applying the adhesive coating composition and allowing the adhesive composition of the invention to flow into and fill any such voids prior to installing the floor covering reduces or eliminates this problem. In the presence of such voids, the maximum thickness of the compositions is not limited, but their depth is typically no more than about 1cm (1/2 inches). Although the compositions of the present invention perform this function satisfactorily, it is common practice to pre-fill and level these floors by selecting from a large number of commonly used compounds.

Primers and/or sealants may be used in conjunction with the magnetic adhesive coating compositions of the present invention. Such primers and/or sealants are typically installed and cured onto the substrate prior to application of the composition, although some do not require full curing prior to application of the composition. Such primers and sealants are used to improve the adhesion of the composition to the substrate and/or to prevent excess moisture from migrating through the substrate and reducing the performance of the composition and/or the covering applied to the cured composition. Various embodiments of the present invention may be formulated to have different water vapor transmission rates and moisture vapor permeability characteristics as desired for various applications. For example, in some cases it may be desirable to have high moisture vapor permeability to allow moisture to migrate freely, while in other cases it may be desirable to completely seal the surface so that little or no moisture may migrate. It may also be desirable in some cases to formulate compositions to seal and prevent migration of radon and/or other toxic gases.

Foaming the adhesive coating composition of the present invention can provide sound and vibration damping as well as greater cushioning under floor or wall coverings. This may be important in areas where acoustic properties play an important role, such as auditoriums or hotels. For example, hotel corridors and rooms often use carpet rather than vinyl floors in order to reduce noise from footsteps and other sources of sound and/or vibration transmitted between floors and/or walls.

Liquid coatings such as paints, varnishes or sealants may also be used on top of the composition, but if another coating is applied on top before installing the magnetically backed floor or wall covering, the low tack adhesion effect becomes diminished. The magnetic attraction force may also be reduced if the top coating is too thick, resulting in a greater distance between the respective magnetically attractive surfaces.

May existIn cases where increased bond strength is required locally, for example at the edges or corners of a sheet flooring. It is helpful to mount the composition in a greater thickness so that a greater density of magnetic and/or magnetizable particles per unit area is present at the edges. This can also be achieved by applying some different type of additional adhesive on top of the cured composition before placing the magnetically backed floor (or wall) covering. If the use of permanent adhesives for this purpose is not ideal, a suitable Repositionable Adhesive may be used, such as that sold by 3M under the designation reproducible 75 Spray Adhesive^TMThe adhesive of (1). The product is packaged in an aerosol spray can and contains about 10% parts by weight of a synthetic elastomer and various solvents and propellants (acetone 30-40%, heptane isomers 20-30%, isobutylene 20-30%, propane 7-13%). The product is easily sprayed onto the surface of the cured composition of the present invention.

The compositions of the present invention may also be used as part of the floor or wall covering itself, for example, applied and cured to the underside of a conventional (non-magnetic backed) floor sheet in the factory or in the field. Such sheets or coverings can be magnetized using known methods while providing an improvement over prior art magnetic backing sheets because the adhesive coating composition has additional low tack inherent adhesive properties. Such low tack magnetic covers, when mounted on a substrate having a cured layer of the adhesive coating composition of the present invention, will actually provide an increase in low tack adhesion due to the low tack adhesion aspect from each respective surface in contact with each other, thereby adding or multiplying the shear adhesion strengths.

Specific examples of compositions, composition components, uses, systems, methods, and apparatuses have been described herein for illustrative purposes.

These are examples only. The techniques provided herein may be applied to systems other than the example systems described above. Many variations, modifications, additions, omissions, and permutations are possible in the practice of this invention. The invention includes variations of the described embodiments that are obvious to a person skilled in the art, including variations obtained by: replacement of features, elements and/or actions with equivalent features, elements and/or actions; mixing and matching features, elements and/or acts from different embodiments described herein with features, elements and/or acts of other technologies; and/or omit combination features, elements, and/or acts from the described embodiments.

While the present invention has been disclosed in its preferred form, the specific embodiments thereof as disclosed herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed herein. Features from different claims or aspects as described above and below may be combined with features of other claims or aspects as described above and below. No single feature, function, element or characteristic of the disclosed embodiments is essential. The claims define certain combinations and subcombinations that are regarded as novel and nonobvious. Other combinations and subcombinations of features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower or equal in scope to the original claims, also are regarded as included within the subject matter of the present disclosure. The invention also covers all embodiments and all applications which will be immediately understood by the expert, after reading the present application, on the basis of his knowledge and optionally simple routine tests. Furthermore, the various embodiments described above can be combined to provide further embodiments.

It is therefore intended that all claims in the claims be interpreted to include all such modifications, permutations, additions, omissions and sub-combinations as may be reasonably inferred. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

1. A composition comprising magnetic and/or magnetizable particles plasticized by polyurethane and derived from a mixture of:

(a) a first component comprising from about 5% to about 20% by weight of the composition of a polymerizable isocyanate; and

(b) a second component comprising:

glycerol esters; and

magnetic and/or magnetisable particles, the magnetic and/or magnetisable particles comprising between about 50% and about 90% by weight of the second component, the remainder being the glyceride.

2. A composition according to claim 1, wherein the mixture of components contains about 11% by weight of isocyanate, the balance being substantially equal amounts by weight of the magnetic and/or magnetizable particles and the glycerides.

3. The composition according to any one of claims 1 to 2, wherein the glycerides are derived from one or more starting materials of agricultural origin.

4. The composition according to any one of claims 1 to 3, wherein the glyceride is castor oil.

5. The composition of any one of claims 1 to 4, wherein the isocyanate is a mixture of 4,4' -diphenylmethane diisocyanate (MDI) and a polymethylene polyphenyl isocyanate.

6. The composition of claim 5, wherein the MDI comprises from about 30% to 60% by weight of the mixture.

7. The composition according to any one of claims 1 to 6, wherein the magnetic and/or magnetizable particles are selected from paramagnetic, superparamagnetic, ferromagnetic and/or ferrimagnetic substances.

8. The composition of claim 7, wherein the particle is selected from the group consisting of: iron, cobalt, nickel, gadolinium, dysprosium, iron-nickel alloys (permalloy), iron (II, III) oxide (magnetite), iron (III) oxide (hematite), ferrosilicon, mixed iron oxides, iron oxides mixed with other metal oxides from the transition element group, such as iron-nickel oxides, or combinations thereof.

9. A composition according to claim 8, wherein the magnetic and/or magnetisable particles comprise iron in the form of ferrosilicon containing at least 50% by weight of iron.

10. The composition of any one of claims 1 to 9, further comprising a pigment.

11. The composition of claim 10, wherein the pigment comprises about 2% by weight of the first component.

12. The composition of any one of claims 1 to 11, further comprising a desiccant.

13. The composition of claim 12, wherein the desiccant comprises about 1% by weight of the first component.

14. The composition of claim 12 or 13, wherein the desiccant is a synthetic zeolite.

15. The composition of any one of claims 1 to 14, further comprising an accelerator to accelerate curing.

16. The composition of claim 15, wherein the accelerator comprises an organometallic compound.

17. The composition of claims 14-15, wherein the organometallic compound comprises dioctyltin Dilaurate (DOTL).

18. The composition of claim 15, wherein the accelerator comprises a tertiary amine.

19. The composition of claim 16, wherein the tertiary amine comprises Dimethylethanolamine (DMEA).

20. A composition comprising iron plasticized by polyurethane and derived from a mixture of:

(b) a second component comprising a mixture of magnetic and/or magnetizable particles and a glyceride, containing from about 50% to about 90% by weight of the magnetic and/or magnetizable particles, the remainder being the glyceride.

21. A composition, comprising:

(a) a first component comprising a polymerizable isocyanate; and

22. A composition, comprising:

(a) a binder; and

(b) magnetic and/or magnetizable particles mixed into the binder, the particles having a minimum diameter of more than 100 nm.

23. The composition of claim 22, wherein the particles comprise from about 30% to about 80% by weight of the total composition.

24. The composition of claim 23, wherein the particles comprise about 67% by weight of the total composition.

25. The composition of any one of claims 22 to 24, wherein the adhesive comprises an ambient temperature cured adhesive.

26. The composition of any one of claims 22 to 25, wherein the adhesive comprises a moisture-curing adhesive.

27. The composition of any one of claims 22 to 26, wherein the adhesive comprises a polymer-based adhesive.

28. The composition of any one of claims 22 to 27, wherein the adhesive comprises a hot melt cured adhesive.

29. The composition of any one of claims 22 to 28, wherein the adhesive comprises a pressure sensitive adhesive.

30. The composition of any one of claims 22 to 29, wherein the adhesive comprises a one-part adhesive.

31. The composition of any one of claims 22 to 29, wherein the adhesive comprises a two-part adhesive.

32. The composition of any one of claims 22 to 29, wherein the binder comprises polyurethane.

33. The composition of any one of claims 22 to 32, wherein the adhesive comprises an elastomer.

34. The composition according to any one of claims 22 to 33, wherein the particles are iron-based particles comprising at least 90 wt% iron (Fe).

35. The composition of any one of claims 22 to 33, wherein the particles are iron-containing ferrosilicon particles comprising 15 to 50 weight percent silicon (Si).

36. A cured composition derived from a mixture comprising:

(a) a first component comprising a polymerizable isocyanate;

(b) a second component comprising a glyceride; and

wherein the polymerizable isocyanate comprises from about 10 wt.% to about 45 wt.% of the cured composition and the magnetic and/or magnetizable particles comprise from about 30 wt.% to about 80 wt.% of the total composition.

37. The composition of claim 36, wherein the glyceride comprises castor oil.

38. The composition of claim 37, wherein the castor oil has been modified by comprising about 1 to 2 weight percent of a pigment.

39. The composition of claim 37 or 38, wherein the castor oil has been modified by including about 0.5 to 1% by weight of a drying agent.

40. A composition according to any of claims 37 to 39 wherein the castor oil has been modified by the inclusion of about 0.01 to 1% by weight of a foaming agent.

41. The composition of any one of claims 37-40, wherein the castor oil has been modified by comprising at least one of an emulsifier and a surfactant.

42. The composition of any of claims 37-41, wherein the castor oil has been modified by inclusion of a curing agent.

43. A composition according to any one of claims 37 to 42, wherein the magnetic and/or magnetisable particles are added to the resulting mixture of first and second components while the resulting mixture is still in a liquid state.

44. A composition according to any one of claims 37 to 42, wherein the magnetic and/or magnetisable particles are added to the second component and the resulting mixture is then mixed with the first component.

45. The composition according to any one of claims 37 to 44, wherein the magnetic and/or magnetisable particles are granular or in the form of powder, flakes or filings or a combination thereof.

46. The composition according to claim 45, wherein the magnetic and/or magnetizable particles are granular or in the form of a powder and have an average diameter of about 10nm to about 500 microns.

47. The composition according to claim 46, wherein the magnetic and/or magnetizable particles have an average diameter greater than 100nm and less than about 500 microns.

48. The composition of any one of claims 37 to 47, wherein the magnetic and/or magnetizable particles comprise iron.

49. A composition according to any one of claims 37 to 48, wherein the magnetic and/or magnetisable particles comprise iron and/or ferrosilicon having a total iron content of at least about 80% by weight.

50. The composition of any one of claims 37 to 49, wherein the magnetic and/or magnetizable particles comprise steel or iron particles encapsulated in a corrosion-resistant coating, comprising a minimum of about 80% by weight iron.

51. A composition according to any one of claims 37 to 50, wherein the magnetic and/or magnetisable particles are selected from paramagnetic, superparamagnetic, ferromagnetic and/or ferrimagnetic substances.

52. The composition of claim 51, wherein the particle is selected from the group consisting of: iron, cobalt, nickel, gadolinium, dysprosium, iron-nickel alloys (permalloy), iron (II, III) oxide (magnetite), iron (III) oxide (hematite), ferrosilicon, mixed iron oxides, iron oxides mixed with other metal oxides from the transition element group, such as iron-nickel oxides, and combinations thereof.

53. An article comprising a cured composition derived from a mixture comprising:

(b) a second component comprising magnetic and/or magnetizable particles and a glyceride, the magnetic and/or magnetizable particles comprising from about 50% to about 90% by weight of the second component, the balance being the glyceride.

54. The article of claim 53 in the form of an elastomeric adhesive.

55. An article according to any one of claims 53 to 54 in the form of a floor or wall covering.

56. The article of any one of claims 53 to 55, in the form of a permanent adhesive coating.

57. The article of any one of claims 53 to 56, in the form of a non-permanent adhesive coating that is permanently adhered to a substrate.

58. The article of any one of claims 53 to 57, wherein the composition comprises:

about 177 parts by weight of magnetic and/or magnetizable particles;

about 69 parts by weight castor oil;

about 30 parts by weight of an isocyanate;

about 1 part by weight of a zeolite.

59. The article of claim 58, wherein the magnetic and/or magnetizable particles comprise iron and/or ferrosilicon with 85% iron.

60. The article of any one of claims 53 to 59, wherein the glyceride comprises castor oil.