Patent Description:
An adhesive is a substance applied to the surface of materials for binding them together and resisting separation. The term "adhesive" may be used interchangeably with glue, cement, mucilage, or paste. The use of adhesives offers many advantages over other binding techniques such as sewing, mechanical fastening, thermal bonding, etc. These advantages include the ability to bind different materials together and to distribute stress more efficiently across a joint.

Moisture curing adhesives cure on exposure to moisture present in the substrate, atmosphere or environment. The curing reaction generally takes place from <NUM>° to <NUM> at a relative humidity of <NUM> to <NUM>%. Under low humidity conditions or where the substrates are impermeable to moisture, moisture can be added during the assembly process to facilitate curing.

Moisture curing polyurethanes are formulated to cure with ambient water and are synthesized from isocyanates, such as aromatic diisocyantes, toluene diisocyanate (TDI) or methylene diphenyl diisocyanate (MDI) and polyols, such as polyether polyols or polyester polyols. Although moisture curing polyurethanes have been and are used in adhesive and coating industries, a major drawback of these adhesives is the inherent use and presence of highly toxic isocyanates. Amongst others considering the high toxicity of isocyanates, there is a continuous need in the art for alternative for moisture curing polyurethane based adhesives.

<CIT> discloses a floor adhesive comprising a polyether modified with silane groups, more particularly a polyether terminated or end-capped with reactive silane groups.

<CIT> discloses a solvent-free and anhydrous hardenable composition that contains at least one polymer A obtainable by reacting a polyether with at least one ethylenically unsaturated silane in the presence of a radical starter, the ethylenically unsaturated silane carrying at least one hydrolyzable group on the silicon atom. The composition provides low viscosity prior to curing along with good elasticity after curing and a broad adhesion spectrum in a solvent-free and water-free hardenable composition.

It is an object of the present invention, amongst other objects, to provide alternatives for polyurethane based adhesives.

The above object, amongst other objects, is met by the present invention through providing a high strength and moisture curing adhesives as outlined in the appended claims.

Specifically, the above object, amongst other objects, is, according to a first aspect, met by the present invention by providing high strength and moisture-curing adhesives comprised of:.

wherein the present adhesive further comprises one or more compounds selected from the group consisting of a radical scavenger, a moisture scavenger, an anti-oxidant, a rheological modifier, and a catalyst, and
wherein the one or more filler material is Neuburg Siliceous earth.

Neuburg siliceous Earth is a natural combination of corpuscular, cryptocrystalline and amorphous silica and lamellar kaolinite and is available from Hoffmann Mineral GmbH (Neuburg, Germany). A preferred Neuburg Siliceous Earth according to the present invention is Sillitin V85 available from Hoffmann Mineral GmbH (Neuburg, Germany).

According to an especially preferred embodiment of this first aspect, the present invention relates to strength and moisture-curing adhesives comprised of:.

Within the context of the present invention weight percentage or % (wt) is defined as the weight of the indicated compound, or composition, as a percentage of the total weight of the present high strength and moisture curing adhesive.

Within the context of the present invention, high strength is defined as:.

According to a preferred embodiment of this first aspect of the present invention, the present silane modified polyether has a dynamic viscosity in the range of <NUM> to <NUM>,<NUM> mPa. , preferably <NUM> to <NUM>,<NUM> mPa. wherein <NUM> Pa. s is <NUM>·m-<NUM>·s-<NUM>.

According to another preferred embodiment, the present modified polyether is composed of one or more α-silane modified polyethers such as <NUM> or <NUM> silane modified polyethers or α-silane modified polyethers although polyethers composed of four, five, six or seven or more are contemplated within the context of the present invention.

Silane modified polyethers are comprised of silane moieties coupled to polyether backbones. Alternatively, polyether chains can also be end-capped with di-or trialkoxysilyl groups provided through urethane coupling with an aliphatic bridge positioned between the urethane group and the silane. This aliphatic bridge can be a methylene group providing an α-silane-terminated polyether. An especially preferred α-silane modified polyether according to the present invention is a silane-modified polymers designated as GENIOSIL® XB <NUM> (viscosity <NUM> to <NUM> mPa. ), GENIOSIL® STP-E10 (viscosity <NUM>,<NUM> to <NUM>,<NUM> mPa. ) and GENIOSIL® STP-E30 (viscosity <NUM>,<NUM> to <NUM>,<NUM> mPa. ) available from Wacker (Munich, Germany).

According to a preferred embodiment of the invention, the present high strength and moisture resistant adhesives comprise <NUM> to <NUM>% (wt%), of a silane modified polyether preferably <NUM> to <NUM>% (wt). Examples of suitable weight percentages of the present modified polyether include <NUM>%, <NUM>% or <NUM>%.

According to yet another preferred embodiment of this first aspect of the invention, the present high strength and moisture resistant adhesives comprise <NUM>% to <NUM>% (wt) of one or more filler material, preferably <NUM>% to <NUM>% (wt). Examples of suitable weight percentages of the present filler material include <NUM>%, <NUM>% or <NUM>%.

The present high strength and moisture resistant adhesives comprise one or more adhesion promotors, such as two or more or three or more. Preferably, the present one or more adhesion promotors are present in an amount a total amount of <NUM> to <NUM>% (wt) such as <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% , <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or <NUM>%.

According to the present invention, preferred one or more adhesion promotors suitable to be used are chosen from the group consisting of.

According to an especially preferred embodiment of the present invention, the present adhesion promotors are selected from the group consisting of an epoxy functionalized alkoxy silane, in an amount of <NUM> to <NUM>% (wt) and an amino functionalized alkoxy silane, in an amount of <NUM> to <NUM>% (wt) and an amino functionalized siloxane, preferably cyclo[<NUM>-((<NUM> aminoethyl)amino)propyl] methylsiloxaan, poly[<NUM>-(<NUM>-aminoethyl)aminopropyl]methyl siloxaan in amount of <NUM> to <NUM> % (wt).

Preferably, the present one or more adhesion promotors are present in an amount of <NUM> to <NUM> % (wt) such as <NUM>,%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>,<NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>,<NUM>%, <NUM>%, <NUM>%, <NUM>,<NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or <NUM>% (wt).

Epoxy functionalized alkoxy silanes hydrolyze in the presence of moisture to form silanols, which than can react with themselves to produce siloxanes. In addition, it leads to an increase in water resistance.

According to yet another preferred embodiment of this first aspect of the invention, the present high strength and moisture resistant adhesives comprise <NUM>% to <NUM>% (wt) of one or more epoxy functionalized alkoxy silane, preferably <NUM>% to <NUM>% (wt), more preferably <NUM>% to <NUM>% (wt). Examples of suitable weight percentages of the epoxy functionalized alkoxy silane include <NUM>%, <NUM>% or <NUM>%.

Amino functionalized alkoxy silanes as an adhesion promotor to improve the mechanical properties e.g. mechanical strength. In addition, it leads to an increase in water resistance. Due to the nature of the amino group, this substance reacts as a base. The silane hydrolyzes autocatalytically in the presence of moisture (methanol is released) to form silanols, which can subsequently react with themselves to produce siloxanes or can bind to inorganic substrates.

According to yet another preferred embodiment of this first aspect of the invention, the present high strength and moisture resistant adhesives comprise <NUM>% to <NUM>% (wt) of one or more amino functionalized alkoxy silane, preferably <NUM>% to <NUM>% (wt), more preferably <NUM>% to <NUM>% (wt). Examples of suitable weight percentages of the amino functionalized akoxy silane include <NUM>%, <NUM>% or <NUM>%.

Amino functionalized siloxanes are used as an adhesion promotor to improve, amongst others, hydrophobicity e.g. improvement of water resistance. In addition, amino functionalized siloxanes provide an improved adhesion on wood. An especially preferred amino functionalized siloxane according to the present invention is an amino functionalized siloxane designated as Wacker GF <NUM> available from Wacker Munich, Germany.

According to yet another preferred embodiment of this first aspect of the invention, the present high strength and moisture resistant adhesives comprise <NUM>% to <NUM>% (wt) of one or more amino functionalized siloxane, preferably <NUM>% to <NUM>% (wt), more preferably <NUM>% to <NUM>% (wt). Examples of suitable weight percentages of the amino functionalized siloxane include <NUM>%, <NUM>% or <NUM>%.

The high strength and moisture resistant adhesive comprise a radical scavenger preferably selected from the group of hindered amine light stabilizers or UV absorbers such as benzotriazole, benzophenone, oxanilide or hydroxyphenyltrianzine.

The high strength and moisture resistant adhesive comprise a moisture scavenger preferably selected from the group of vinyl functionalized alkoxy silanes such as vinyltriethoxysilane, vinyltrimethoxysilane, dichloromethylvinylsilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, vinyltriacetoxysilane, chlorodimethylvinylsilane, vinyltrichlorosilane, vinyltris(<NUM>-methoxyethoxy)silane, <NUM>,<NUM>,<NUM>,<NUM>-tetravinyl-<NUM>,<NUM>,<NUM>,<NUM>-tetramethylcyclotetrasiloxane, oligomeric vinylsilane, Vinyltri(isopropoxy)silane, Vinyl silane Polymer, Vinylsilane preparation, Vinyltriacetoxysilane.

The high strength and moisture resistance adhesive comprise an antioxidant such as a primary antioxidant or a secondary antioxidant, hindered phenyl AO, phosphite AO or thioether AO.

The present high strength and moisture resistant adhesive comprise a rheological modifier preferably selected from the group consisting of a polyolefin blend, hydrophobic silica, hydrophilic silica, polyamide wax and ultra fine precipitated calcium carbonate grades.

The high strength and moisture resistant adhesive comprise a catalyst a dibasic Amine, tin compounds and a titanate catalyst.

According to a second aspect, the present invention relates to the use of a combination of a silane or α-silane modified polyether, Neuburg Siliceous Earth filler material and the combination of an epoxy functionalized alkoxy silane an amino functionalized alkoxy silane and an amino functionalized siloxane for providing an adhesive.

The present invention will further be illustrated in the following example of an especially preferred embodiment of the present invention.

The following composition providing a high strength and moisture resistant adhesive was prepared (amounts are indicated in %(wt)):.

The above adhesive was tested in conformity with EN204/EN205 and the test conditions can be summarized as:.

Under the above conditions, the present adhesives provided:.

Claim 1:
High strength and moisture resistant adhesive suitable to be used as a moisture curing adhesive, said adhesive comprises:
a) <NUM> to <NUM> % (wt) of one or more modified polyethers, wherein the one or more modified polyethers are silane modified polyethers;
b) <NUM> to <NUM>% (wt) of one or more filler material;
c) <NUM> to <NUM>% (wt) adhesion promotors said adhesion promotors are a combination of an epoxy functionalized alkoxy silane, an amino functionalized alkoxy silane and an amino functionalized siloxane;
wherein said adhesive further comprises one or more compounds selected from the group consisting of a radical scavenger, a moisture scavenger, an anti-oxidant, a rheological modifier, and a catalyst;
wherein said one or more filler material is Neuburg Siliceous Earth; and
wherein high strength is defined as:
<NUM>) having a strength of more than ≥<NUM> N/mm<NUM> after <NUM> days in a standard atmosphere;
<NUM>) having a strength of more than ≥<NUM> N/mm<NUM> after <NUM> days in a standard atmosphere and <NUM> days in water at <NUM> ± <NUM>;
<NUM>) having a strength of more than ≥<NUM> N/mm<NUM> after <NUM> days in a standard atmosphere <NUM> hours in boiling water and <NUM> hours in water at <NUM> ± <NUM>;
wherein the present strength is determined in accordance with EN <NUM>: Classification of thermoplastic wood adhesives for non-structural applications and EN205: Wood adhesives for non-structural applications or determination of tensile shear strength of lap joints.
<NUM>) having a strength of more than ≥ <NUM> N/mm<NUM> after <NUM> days in standard atmosphere <NUM> hour in a preheated fan oven, at <NUM> ± <NUM>,<NUM> for <NUM> ± <NUM>
wherein the present strength is determined in accordance with EN <NUM>: Determination of tensile strength of lap joints at elevated temperature (WATT <NUM>)