DESC:Field of Invention
The present invention provides for an adhesive formulation favouring high grab holding capability such as of objects on substrates, which adhesive formulation is also easily removable free of any damage caused to the object/ substrate.
Preferably the present invention relates to liquid adhesive formulation comprising dimethoxy silyl polyether terminated PU polymer resin blended with select nano- & micron- sized inorganic fillers and polymeric filler/s including polytetrafluroroethylene, polystyrene, polyethylene, polypropylene, enabling high load holding capability and can even replace nail. Said adhesive formulation of the present invention is advantageously further easy to apply without the need of tools/technician, and is easily squeezable for optimal application.
Background of the Invention
Current practice for fixing household objects is by using nails. Many a times technicians and tools like drilling machine, hammer, screwdriver etc are required for fixing objects. During fixing there are likely chances of damage to the objects and substrates (wall, ceramic, wooden, concrete, floor panel or other rigid surfaces). More importantly there will be permanent damages to the substrates and/or objects while removal which also spoils the aesthetics.
Technical deficiency: There are few adhesive products currently available in Indian market which are nail free with high grab. However, they do not address other issues such as ease of application, easy removability, requirement for special application tool, odor.
Existing product compositions are based on branched dimethoxysilane MS (modified silicone) polymer with fillers and additives.
EP3255113A1 teaches a method for manufacturing a composition (C) suitable for use as a sealant and/or adhesive which comprises the steps of: step 1: mixing at least one silane-modified polymer (P) with at least one hydrophobic fumed silica (S) having a BET surface area of at least 50 m2/g so as to obtain a mixture (M), wherein said mixture (M) has a tack value To, measured in accordance with the rheological tack test method, equal to or less than 1000 Pa; step 2: adding to the mixture (M) as obtained in step 1, at least one rheology modifier (R) thereby forming the composition (C).
EP3617249 A1 method for manufacturing a composition (C) suitable for use as a sealant and/or adhesive which comprises the steps of: step 1: providing a container comprising a mixture (M) [filled container (F), herein after], wherein the mixture (M) is prepared by mixing at least one silane-modified polymer [silane-modified polymer (P), herein after] with at least one heat activatable rheology modifier having an activation temperature T [rheology modifier (R), herein after], wherein the mixing is carried out at a mixing temperature below the activation temperature T of the rheology modifier (R); step 2: heating the filled container (F) to above the activation temperature T of the rheology modifier (R), thereby transforming the mixture (M) into a composition (C) inside the filled container (F).
WO 2010/105814 teaches adhesive composition comprising : - at most 15 % of a PolyPropylene (or PP) having a melting point between 300C and 100°C; - from 30 to 60 % of a cross-linkable polymer with silyl end groups comprising cross- linking groups bonded to the silicon atom, said cross-linkable polymer having a functionality of on average 3-12 cross-linking groups; - a cross-linking catalyst for the polymer; - a water scavenger; and - a rheology controller. The composition of this prior art is suitable for direct glazing of a windscreen on a metallic automotive frame.
EP2682432A1 provides a curable composition useful as a contact adhesive which has a high rate of initial tack development, high tack strength, and long retention time of the developed tack. The curable composition includes an organic polymer (Q) containing a reactive silyl group, and a linear organic polymer (P) having a number average molecular weight larger than that of the polymer (Q) and having a reactive silyl group containing three hydrolyzable groups at only one terminal. The organic polymer (P) and the organic polymer (Q) are mixed at a mixing ratio (P):(Q), in terms of parts by weight, of 60:40 to 5:95.
Traversal of the prior art reveals that while various prior adhesive compositions are known there is still a need in the art to explore for formulations/ compositions that can replace nail in having high grab holding capability for high loads and would be easy to apply without the need of tools/ technician and would also be easily squeezable for optimal application and most importantly would be easily removable.
Objectives of the Invention
Thus the primary object of the present invention is to provide for adhesive formulations that would have high grab holding capability for high loads and at the same time would also be easily removable.
It is another object of the present invention to provide for said high grab adhesive formulation that would be easy to apply free of any need of tools and technicians and would also be easily squeezable for optimal application.
It is yet another object of the present invention is to provide for said high grab adhesive formulation that would also be easily removable without any damage to the substrate/object.
Summary of the Invention
Thus according to the basic aspect of the present invention there is provided high grab adhesive formulation comprising synergistically co-acting 20-25 wt.% dimethoxy silyl polyether terminated PU polymer resin blended with 29-35 wt.% polymeric fillers, 25-32 wt.% nano- & micron- sized inorganic fillers adapted for high grab attributes having high load holding capability on multiple surfaces that is a replacement to nails with easy removability without the need for nails.

Preferably said high grab adhesive formulation is provided wherein such polymeric filler/s include >400 Mesh-max 35 to <400 Mesh-Min 65 microparticles of polytetrafluroroethylene, polystyrene, polyethylene, polypropylene; and said nano- & micron- sized inorganic fillers include CaCO3.

According to another preferred aspect of the present invention there is provided said high grab adhesive formulation wherein said formulation incorporates plasticizers including Diisononyl phthalate, hindered amine based stabilizers including bumetrizole 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol, amine based adhesion promoters including N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane, Aminopropyltriethoxysilane, moisture scavengers including Vinyltrimethoxysilane, and said dimethoxy silyl polyether terminated PU polymer resin have viscosity levels of 19.5-28.5 Pa·s at 25-40 ?C.

Advantageously said high grab adhesive formulation is neutral curing, odourless, is isocyanate free, is non-corrosive towards metals, and is also free of any shrinkage or bubble.

According to another preferred aspect of the present invention there is provided said high grab adhesive formulation having improved rheological property for improved consumer comfort, adheres to varied surfaces free of primers and even on damp surfaces including Beach wood, Stainless Steel Plate, Mild Steel Plate, High Density Polyethylene, Acrylic Sheets that is easy to remove by hand pressure from surface free of causing any surface stain.

According to another aspect of the present invention there is provided a process for manufacturing the high grab adhesive formulation comprising the step of
(i) providing selective ingredients of 20-25 wt.% dimethoxy silyl polyether terminated PU polymer;
(ii) providing 29-35 wt.% polymeric filler/s,
(iii) providing 25-32 wt.% nano- & micron- sized inorganic fillers;
(iv) blending the same in presence of curing catalyst to obtain said high grab adhesive formulation in the form of paste.

Preferably in said process for manufacture said blending is done in the presence of catalyst and plasticizers including Diisononyl phthalate, hindered amine based stabilizers including bumetrizole 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol, amine based adhesion promoters including N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane, Aminopropyltriethoxysilane, moisture scavengers including Vinyltrimethoxysilane.

More preferably in said process said catalyst includes Dibutyltin dilaurate.

Detailed Description of the Invention
As stated hereinbefore, the present invention relates to an adhesive formulation favouring high grab holding capability such as of objects on substrates, which adhesive is also easily removable without causing any damage to the objects/ substrate.
Thus according to an aspect of the present invention there is provided high grab adhesive formulation preferably liquid adhesive formulation comprising dimethoxy silyl polyether terminated PU polymer resin blended with select nano- & micron- sized inorganic fillers and polymeric filler/s including polytetrafluroroethylene, polystyrene, polyethylene, polypropylene, adapted for high grab attributes having high load holding capability and can even replace nail with easy removability on multiple surfaces without the need for nails.

Said adhesive formulation of the present invention is advantageously further easy to apply without the need of tools/technician, and is easily squeezable for optimal application.
While the current adhesives available in Indian market are based on branched dimethoxysilane PU polymer with fillers and additives which has only high grab property, in the backdrop of which the present formulation/ composition comprises select dimethoxy silyl- polyether terminated PU polymer which when blended with select inorganic and polymeric fillers gets adapted for high grab attributes having high load holding capability and can even replace nail with easy removability on multiple surfaces without the need for nails. The test examples are given under the Tables below:

EXAMPLES:

Table 1

Type / Category Ingredients including optional ingredients T-1 T-2 T-3 T-4 T-5 T-6
Resin Dimethoxy Silyl- polyether terminated PU polymer 25 23 24 21 21 21
Viscosity of the above resin Viscosity : 19.5 – 28.5 Pa·s at 25-40 ?C, Moisture : 0.1% by wt.% or <1000 ppm or less

Plasticizer Diisononyl phthalate 7.8 8.8 8.8 7.8 7.8 7.8
Filler Nano Calcium Carbonate (CaCO3) 47.65 46.65 46.65 16.65 21.65 11.65
Filler 2 micron CaCO3 10 11 10 10 10 10
Filler Polystyrene Microparticles
> 400 Mesh - max 35
<400 Mesh - Min 65 35 30 40
Pigment Titanium dioxide 4.5 5.5 5.5 4.5 4.5 4.5
Fumed Silica Pyrogenic silica 2.2 2.2 2.2 2.2 2.2 2.2
Antioxident 0.2 0.2 0.2 0.2 0.2 0.2
Hindered amine light stabilizers bumetrizole 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol 0.2 0.2 0.2 0.2 0.2 0.2
UV absorber Bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate 0.2 0.2 0.2 0.2 0.2 0.2
Moisture Scavenger Vinyltrimethoxysilane 0.9 0.9 0.9 0.9 0.9 0.9
Amine Based Adhesion Promoter N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane 0.7 0.7 0.7 0.7 0.7 0.7
Amine Based Adhesion Promoter Aminopropyltriethoxysilane 0.2 0.2 0.2 0.2 0.2 0.2
Catalyst DBTDL- Dibutyltin dilaurate 0.45 0.45 0.45 0.45 0.45 0.45
Total 100 100 100 100 100 100

Grab Medium Medium Low High High No Bonding
Wet Load Bearing (after 30 sec of application) 100 gms 95 gms Sagging 90 gms 75 gms No Bonding
Easy Removability after 7 days of curing No No No Yes Yes No Bonding

From the above table it can be inferred that the variants covered are not only extremely important for working of the high grab formulation of the present invention but also the levels in which it is involved are important as is flowing from the results of sample T6.

Easy removability of present adhesive from substrate is the additional attribute suiting the consumers demand and bringing them comfort willing to remove bonded articles after 7 days, and normally post seven days they are strong and requires force for removal while removing bonded articles adhered to it.

Dimethoxy silyl-polyether terminated PU polymer is the selective ingredient as it is found to have better storage stability when in synergistic combination with other ingredients due to lower reactivity compared to Trimethoxy Silyl polyether terminated PU Polymer. Typically Trimethoxy Silyl polyether terminated PU Polymer in being fast curing resins while may be suitable for high grab adhesive, but due to its lower stability Dimethoxy Silyl polyether terminated PU Polymer is preferred over Trimethoxy Silyl polyether terminated PU Polymer that synergizes with other ingredients of the formulation to provide for the desired attributes.

Table 2

Trial No. Test Standard T-1 T-2 T-3 T-5 T-4 T-6
1 Colour White White White White White White
2 Consistency Thick Paste Thick Paste Thick Paste Thick Paste Thick Paste Thick Paste
4 Skin Formation time, min ASTM C679 10 10 10 10 10 10
5 Volume shrinkage after 7 days, % ASTM C 1241 2.63 2.35 2.35 2.45 2.68 2.1
6 Solid by mass, % 99.67 99.64 99.64 99.87 99.68 99.85
7 Drying time for 3mm bed, hrs ASTM C679 24 24 24 24 24 24
8 Elongation, %, ASTM D 412
7 Days 230 210 180 190 210 189
9 Tensile strength, Mpa, ASTM D 412
7 days, 2.48 2.38 2 1.67 2.04 2.01
10 Shore A hardness ASTM C661
7 Days 62 53 50 58 54 52
11 Peel Adhesion,
C/F - Cohesive Failure ASTM D 4541
7 Days, on glass plate, N/ inch 63 C/F 63 C/F 62 C/F 65 C/F 62 C/F 68 C/F
7 Days, on Aluminium 60 C/F 60 C/F 59 C/F 67 C/F 65 C/F 67 C/F
12 Lap sheer adhesion on multiple substrates, Mpa, 24 hrs ASTM D 4541/ASTM D3163
Beach wood 1.91 1.87 1.8 1.35 1.31 1.54
Stainless Steel Plate 1.4 1.68 1.6 1.06 1.01 1.15
Mild Steel Plate 2.7 2.01 1.98 1.78 1.68 1.25
High Density Polyethylene 0.35 1.31 1.21 1.02 1.01 0.87
Acrylic Sheets 2.1 0.98 0.9 1.17 0.67 0.98
12 Lap sheer adhesion on multiple substrates, Mpa, 7 Days ASTM D 4541/ASTM D3163
Beach wood 2.1 1.89 1.8 1.28 1.29 1.52
Stainless Steel Plate 1.99 1.75 1.7 1.21 1.10 1.12
Mild Steel Plate 2.54 1.48 1.39 1.07 1.05 1.21
High Density Polyethylene 0.53 0.54 0.49 0.99 0.89 0.82
Acrylic Sheets 2.12 1.8 1.7 1.2 1.19 0.85
15 Pull of Adhesion on multiple substrates, 1 Day, Mpa, 0.08 g/ 20 mm dolly material is deposited. ASTM D 454
Stainless Steel Plate 2.37 1.78 1.7 1.62 1.28 1.43
Mild Steel Plate 2.3 1.89 1.79 1.45 1.35 1.61
Marble - Grey Colour 2.5 1.98 1.8 1.34 1.65 1.54
Granite 2.4 1.86 1.8 1.38 1.24 1.24
Concrete 2.86 2.05 1.9 1.35 1.12 1.11
14 Pull of Adhesion on multiple substrates, 7 Day, Mpa
0.08 g/ 20 mm dolly material is deposited. ASTM D 454
Stainless Steel Plate 2.42 2.02 1.9 1.41 1.39 1.42
Mild Steel Plate 2.51 2.09 1.89 1.49 1.49 1.09
Marble - Grey Colour 2.57 2 1.9 1.42 1.69 2.38
Granite 2.62 1.92 1.85 1.41 1.48 1.69
Concrete 2.8 1.98 1.89 1.57 1.24 1.59

According to an embodiment of the present invention a process for manufacture of high grab adhesive formulation is provided based on the steps of
(i) providing selective ingredients of 20-25 wt.% dimethoxy silyl polyether terminated PU polymer;
(ii) providing 29-35 wt.% polymeric filler/s,
(iii) providing 25-32 wt.% nano- & micron- sized inorganic fillers;
(iv) blending the same in presence of curing catalyst to obtain said high grab adhesive formulation in the form of paste; and wherein said blending is done in the presence of catalyst and plasticizers including Diisononyl phthalate, hindered amine based stabilizers including bumetrizole 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol, amine based adhesion promoters including N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane, Aminopropyltriethoxysilane, moisture scavengers including Vinyltrimethoxysilane.

The adhesive formulation of the present invention has the following advantages:
(a) Higher grab as compared to available commercial product
(b) Improved rheological property for improved consumer comfort
(c) Easy to remove by hand pressure
(d) No stain on the surface post removal of the adhesive
(e) Product is neutral curing and odourless
(f) Isocyanate free
(g) Adheres perfectly without primer on most, even damp surfaces
(h) No shrinkage and bubble free
(i) Non-corrosive towards metals.

It is thus possible for the present invention to provide for adhesive formulations preferably liquid adhesive formulations comprising of synergistically co-acting 20-25 wt.% dimethoxy silyl polyether terminated PU polymer blended with 29-35 wt.% polymeric filler/s, 25-32 wt.% nano- & micron- sized inorganic fillers adapted for high grab attributes on multiple surfaces having high load holding capability that is a an easy replacement to nails with easy removability also from multiple surfaces without the need for nails.
,CLAIMS:We Claim:

1. High grab adhesive formulation comprising synergistically co-acting 20-25 wt.% dimethoxy silyl polyether terminated PU polymer resin blended with 29-35 wt.% polymeric fillers, 25-32 wt.% nano- & micron- sized inorganic fillers adapted for high grab attributes having high load holding capability on multiple surfaces that is a replacement to nails with easy removability without the need for nails.

2. The high grab adhesive formulation as claimed in claim 1 wherein such polymeric filler/s include >400 Mesh-max 35 to <400 Mesh-Min 65 microparticles of polytetrafluroroethylene, polystyrene, polyethylene, polypropylene; and said nano- & micron- sized inorganic fillers include CaCO3.

3. The high grab adhesive formulation as claimed in claim 1 wherein said formulation incorporates plasticizers including Diisononyl phthalate, hindered amine based stabilizers including bumetrizole 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol, amine based adhesion promoters including N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane, Aminopropyltriethoxysilane, moisture scavengers including Vinyltrimethoxysilane, and said dimethoxy silyl polyether terminated PU polymer resin have viscosity levels of 19.5-28.5 Pa·s at 25-40 ?C.

4. The high grab adhesive formulation as claimed in claims 1-3 wherein said formulation is neutral curing, odourless, is isocyanate free, is non-corrosive towards metals, and is also free of any shrinkage or bubble.

5. The high grab adhesive formulation as claimed in claims 1-4 having improved rheological property for improved consumer comfort, adheres to varied surfaces free of primers and even on damp surfaces including Beach wood, Stainless Steel Plate, Mild Steel Plate, High Density Polyethylene, Acrylic Sheets that is easy to remove by hand pressure from surface free of causing any surface stain.

6. A process for manufacturing the high grab adhesive formulation as claimed in claims 1-5 comprising the step of
(i) providing selective ingredients of 20-25 wt.% dimethoxy silyl polyether terminated PU polymer;
(ii) providing 29-35 wt.% polymeric filler/s,
(iii) providing 25-32 wt.% nano- & micron- sized inorganic fillers;
(iv) blending the same in presence of curing catalyst to obtain said high grab adhesive formulation in the form of paste.

7. The process for manufacture as claimed in claim 6 wherein said blending is done in the presence of catalyst and plasticizers including Diisononyl phthalate, hindered amine based stabilizers including bumetrizole 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol, amine based adhesion promoters including N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane, Aminopropyltriethoxysilane, moisture scavengers including Vinyltrimethoxysilane.

8. The process for manufacture as claimed in claims 6 or 7 wherein said catalyst includes Dibutyltin dilaurate.

Dated this the 8th day of December, 2023 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent & Advocate)
IN/PA-199