Claims:WE CLAIM:

1. A coating composition prepared by reacting by blending a component A and component B wherein
said component A comprises:
i) a first polyol resin having hydroxyl (OH) content in the range of 1.4 to 2.0, in an amount in the range of 7 wt% to 11 wt%;
ii) a second polyol resin having hydroxyl (OH) content in the range of 3.0 to 4.0, in an amount in the range of 14 wt% to 22 wt%;
iii) a liquid carrier in an amount in the range of 45 wt% to 55 wt%;
iv) a matting agent in an amount in the range of 3 wt% to 10 wt%;
v) a metal based catalyst, in an amount in the range of 0.5 to 1.5 wt%;
vi) a surface feel additive in an amount in the range of 5 wt% to 9 wt%; and
vii) a slip additive in an amount in the range of 0.1 wt% to 1 wt%
said component B comprises
i. a polyisocyanate having isocyanates (NCO) content in the range of 22 to 24, in an amount in the range of 8 wt% to 12 wt%;
wherein the weight percentages are with respect to the total weight of the coating composition.
2. The coating composition as claimed in claim 1, wherein the component A comprises:
i) a first polyol resin having hydroxyl content in the range of 1.4 to 2.0, in an amount in the range of 7 wt% to 11 wt%;
ii) a second polyol resin having hydroxyl content in the range of 3.0 to 4.0, in an amount in the range of 14 wt% to 22 wt%;
iii) butyl acetate as a liquid carrier, in an amount in the range of 45 wt% to 55 wt%;
iv) amorphous silica as a matting agent in an amount in the range of 3 wt% to 10 wt%;
v) dibutyl tin dibutyl laurate as a catalyst, in an amount in the range of 0.5 to 1.5 wt%;
vi) a dispersion of an oxidized high density polyethylene (HDPE) wax as a surface feel addtive in an amount in the range of 5 wt% to 9 wt%; and
vii) polyether-modified polydimethylsiloxane as a slip additive in an amount in the range of 0.1 wt% to 1 wt%; and
the component B comprises
hexamethylene diisocyanate trimer as a polyisocyanate having isocyanates (NCO) content in the range of 22 to 24, in an amount in the range of 8 wt% to 12 wt%;
wherein the weight percentages are with respect to the total weight of the coating composition.
3. The composition as claimed in claim 1, wherein the weight ratio of said first polyol resin to said second polyol resin is 1:2.
4. The composition as claimed in claim 1, wherein said liquid carrier is at least one selected from Butyl acetate and ortho xylene.
5. The composition as claimed in claim 1, wherein said first polyol resin is at least one selected from the group consisting of polycarbonate polyol, polycarbonate polyester polyol and linear aliphatic polycarbonate polyester polyol.
6. The composition as claimed in claim 5, wherein said linear aliphatic polycarbonate polyester polyol is based on hexane diol-1,6 e caprolactum having hydroxyl (OH) content in the range of 1.5 to 1.9.
7. The composition as claimed in claim 1, wherein said second polyol resin is at least one selected from polyester polyol, branched polyester polyol, and solvent free polyester polyol.
8. The composition as claimed in claim 7, wherein said branched polyester polyol has a hydroxyl (OH) content in the range of 3.2 to 3.8.
9. The composition as claimed in claim 1, wherein said matting agent is a synthetic amorphous silica having an average particle size in the range of 7 – 10 µm, pore volume (H2) 1.8 ml/g, and carbon content in the range of 6.0 - 9.0 %.
10. The composition as claimed in claim 1, wherein said composition is applied on wooden substrate followed by curing at a temperature in the range of 25 oC to 30 oC.
11. The composition as claimed in claim 1, wherein
the component A comprises
i) linear aliphatic polycarbonate polyester polyol based on hexane diol-1,6 e caprolactum, as a first polyol resin having hydroxyl (OH) content in the range of 1.5 to 1.9, in an amount of 9 wt%;
ii) branched hydroxyl polyester, as a second polyol resin having hydroxyl (OH) content in the range of 3.2 to 3.8, in an amount of 18 wt%;
iii) butyl acetate having moisture content upto 0.2 wt% of the liquid carrier, in an amount of 50.8 wt%;
iv) amorphous silica in an amount of 4 wt%;
v) dibutyl tin dilaurate, in an amount of 1 wt%;
vi) a dispersion of an oxidized high density polyethylene (HDPE) wax in an amount of 7 wt%; and
vii) polyether-modified polydimethylsiloxane in an amount of 0.2 wt%;
wherein the weight ratio of said first polyol to said second polyol is 1:2.
component B comprises
i. hexamethylene diisocynate trimer as a polyisocyanate having isocyanates (NCO) content in the range of 22 to 24, in an amount of 10 wt%.
wherein the weight percentages are with respect to the total weight of the coating composition.
12. The coating composition as claimed in claim 1, where said coating composition includes a thinner added in predetermined quantity to adjust the viscosity of the coating composition, said thinner comprising a combination of butyl acetate and ortho xylene in a ratio in the range of 70:30 to 50:50.

13. The coating composition as claimed in claim 12, wherein a viscosity of said coating composition is in the range of 30 to 54 centipoise.
14. A process for preparing the coating composition as claimed in claim 1,said process comprising the following steps:
i. mixing a first polyol resin having hydroxyl (OH) content in the range of 1.4 to 2.0, a second polyol resin having hydroxyl (OH) content in the range of 3.0 to 4.0, and at least one liquid carrier under stirring to obtain a mixture;
ii. adding a matting agent to said mixture to obtain a dispersion;
iii. mixing a predetermined quantity of a surface feel additive, a slip additive, and a metal based catalyst in said dispersion to obtain a component A;
iv. obtaining a component B comprising polyisocyanate having isocyanate (NCO) content in the range of 22 to 24; and
v. blending and reacting said component B in an amount in the range of 8 wt% to 12 wt% with with said component A at a temperature in the range of 25 oC to 30 oC to obtain the coating composition to be applied on a substrate.

15. The process as claimed in claim 14, wherein said process includes steps of i) adding a thinner in predetermined quantity to adjust the viscosity of the coating compositions, ii) aging the coating composition after addition of said thinner.

16. The process as claimed in claim 15, wherein, said thinner comprising a combination of butyl acetate and ortho xylene in a ratio in the range of 70:30 to 50:50.
17. The process as claimed in claim 14, wherein a weight ratio of said polyol resin to said matting agent is in the range of 8:1 to 6:1.
18. The process as claimed in claim 14, wherein said thinner is at least one selected from butyl acetate and ortho xylene.
19. The process as claimed in claim 14, wherein a weight ratio of said first polyol resin to said second polyol resin is 1:2.
20. The process as claimed in claim 14, wherein said first polyol resin is at least one selected from the group consisting of polycarbonate polyol, polycarbonate polyester polyol and linear aliphatic polycarbonate polyester polyol.
21. The process as claimed in claim 14, wherein said liquid carrier is at least one selected from butyl acetate and ortho xylene.
22. The process as claimed in claim 14, wherein said second polyol resin is at least one selected from polyester polyol, branched polyester polyol, and solvent free polyester polyol.
23. The process as claimed in claim 14, wherein said branched polyester polyol has a hydroxyl (OH) content in the range of 3.2 to 3.8.
24. The process as claimed in claim 14, wherein said substrate is wooden substrate.
25. A kit for a coating composition comprising:
I. Container A containing component A in an airtight manner, wherein component A comprises:
i) a first polyol resin having hydroxyl (OH) content in the range of 1.4 to 2.0, in an amount in the range of 7 wt% to 11 wt%;
ii) a second polyol resin having hydroxyl (OH) content in the range of 3.0 to 4.0, in an amount in the range of 14 wt% to 22 wt%;
iii) butyl acetate as liquid carrier having moisture content in the range of 0 wt% to 0.2 wt% of the liquid carrier, in an amount in the range of 45 wt% to 55 wt%;
iv) amorphous silica as matting agent in an amount in the range of 3 wt% to 10 wt%;
v) dibutyl tin dilaurate as metal based catalyst in an amount in the range of 0.5 wt% to 1.5 wt%;
vi) a dispersion of an oxidized high density polyethylene (HDPE) wax as surface feel additive in an amount in the range of 5 wt% to 9 wt%; and
vii) polyether-modified polydimethylsiloxane as slip additive in an amount in the range of 0.1 wt% to 1 wt%;
II. Container B containing component B, in an airtight manner, wherein component B comprises:
i) hexamethylene diisocynate trimer as polyisocyanate having isocyanates (NCO) content in the range of 22 to 24, in an amount in the range of 8 wt% to 12 wt%;
wherein the weight percentages are with respect to the total weight of the coating composition.
III. Container C for housing the container A and the container B therewithin and an instruction sheet explaining how the component A has to be mixed with the component B to obtain the coating composition just before application of the coating composition on a substrate, which is in need of the coating composition.
26. The kit as claimed in claim 25, wherein the instruction sheet provides instructions for mixing every 1 part of the component B with 7-11 parts of the component A and blending the components A and the component B to form a homogeneous blend to be applied as the coating composition on said substrate.
27. The kit as claimed in claim 26, wherein said kit includes container D containing a thinner which can be added to the homogeneous blend to alter its viscosity.
28. The kit as claimed in claim 27, wherein the thinner comprising a combination of butyl acetate and ortho xylene in a ratio in the range of 70:30 to 50:50
29. The kit as claimed in any one of the claims 25, 26 and 27 which includes a spatula for blending the components.
30. The kit as claimed in claim 25, wherein said substrate is wooden substrate.
, Description:FIELD
The present disclosure relates to a coating composition.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Isocynate content – The term “isocyanate (NCO) content” refers to the the concentration of the active NCO groups in the sample. The NCO content is given in g of isocyanate per 100 g of sample. NCO content is calculated by reacting NCO containing sample with excess of primary amine and back titrating the unreacted primary amine with hydrochloric acid.
Hydroxyl content referes to a weight percentage of hydroxyl groups of a polyol compound and can be calculated from OH number by the following equation:

Hydroxyl Number/Hydroxy value (OH number) refers to a number arising from a wet analytical method for the hydroxyl content of a polyol. It is the milligram of Potassium hydroxide equivalent to the content of free hydroxyl groups in one gram of the polyol.

OH Number = (56.1 x 1000)/ equivalent weight
where 56.1 is the atomic weight of Potassium hydroxide and 1000 is the number of milligram in one gram of the sample.

Matting Agent – The term “Matting Agent” refers to additives based on silicas, waxes, organic materials and fillers, which are added to the paint, to form a micro-rough surface after the drying process to achieve a matty appearance.
Ambient conditions – The term “ambient conditions” refers to the standard conditions of temperature and pressure for experimental measurements. In the present disclosure the standard temperature is in the range of 25 to 30 °C, whereas the standard pressure is atmospheric pressure (i.e. 1 atmosphere).
Stain resistance – The term “stain resistance” refers to the ability of a surface to withstand discolouration or surface damage caused by contact with liquids, including oil and grease, and/or solid surfaces. Commonly, a liquid stain occurs as a result of a material surface being wetted, and on drying the surface of the material becomes unintentionally discoloured i.e. stained.
Soft Feel Coating – The term “Soft Feel Coating” refers to a coating that, when applied, not only protects the material surface but also imparts a soft, grippy or rubbery feel to the otherwise hard material, and creates a velvety texture and the surface becomes "soft" to touch or feel, and increases the tactile appeal.
Equivalent Weight - classically defined as the molecular weight of a polyol divided by its functionality. In practice, the equivalent weight is calculated from the analyzed hydroxyl (OH) value. The equivalent weight is necessary for isocyanate requirement calculations and is derived from the following expression:
Equivalent weight of NCO sample = (4200/ NCO content)
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Wood substrate has fibrous hydrophilic groups on the surface. Further, the uneven grainy pattern and the porous surface, makes the coating on a wooden substrate difficult. Further, due to the absorption, adsorption and chemical reactions taking place at the surface of the wooden substrate, coating on the wooden surface becomes even more challenging.
Conventionally, a coating composition providing a soft feel comprises a soft resin which is primarily linear in nature and has a wax additive to impart surface softness. Linear structure and the wax additive lead to the coating composition that is extremely slow at drying. As a result of which it becomes essential and necessary to cure the coating composition at an elevated temperature to reduce the drying time. The curing of the coating composition at high temperature leads to improved surface hardness of the coating in terms of pencil hardness, however it leads to dust pickup. In order to prepare a coating composition that can be cured at an optimum rate and at ambient conditions, it must inherently have a faster curing rate, which will result in compromising on soft feel. Therefore, it is a challenge to provide the coating composition that has the required strength to withstand resistance to domestic stains, normal wear & tear, and at the same time has a soft feel.
There is, therefore, felt a need for a coating composition that alleviates the aforementioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a coating composition for a wooden surface.
Another object of the present disclosure is to provide a coating composition for a wooden substrate that cures at ambient conditions i.e, 27 – 30°C and relative humidity 60% maximum, to provide a soft feel.
Yet another object of the present disclosure is to provide a coating composition for a wooden substrate that undergoes curing under ambient conditions and forms a tough film.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
In a first aspect, the present disclosure relates to a coating composition prepared by reacting by blending a component A and a component B.
The component A comprises:
i) a first polyol resin having hydroxyl (OH) content in the range of 1.4 to 2.0, in an amount in the range of 7 wt% to 11 wt%;
ii) a second polyol resin having hydroxyl (OH) content in the range of 3.0 to 4.0, in an amount in the range of 14 wt% to 22 wt%;
iii) a liquid carrier in an amount in the range of 45 wt% to 55 wt%;
iv) a matting agent in an amount in the range of 3 wt% to 10 wt%;
v) a metal based catalyst, in an amount in the range of 0.5 to 1.5 wt%;
vi) a surface feel additive in an amount in the range of 5 wt% to 9 wt%; and
vii) a slip additive in an amount in the range of 0.1 wt% to 1 wt%;
wherein the weight ratio of the first polyol to the second polyol is 1:2.
The component B comprises:
i. a polyisocyanate having isocyanates (NCO) content in the range of 22 to 24, in an amount in the range of 8 wt% to 12 wt%;
wherein the weight percentages are with respect to the total weight of the coating composition.
In a second aspect, the present disclosure relates to a process for preparing a coating composition. The process comprises mixing a first polyol resin having hydroxyl (OH) content in the range of 1.4 to 2.0, a second polyol resin having hydroxyl (OH) content in the range of 3.0 to 4.0, and at least one liquid carrier under stirring to obtain a mixture. A matting agent is added to the mixture to obtain a dispersion. A predetermined quantities of a surface feel additive, slip additive and a metal based catalyst are mixed in the dispersion to obtain a component A. Component B comprising hexamethylene diisocynate trimer as a polyisocyanate having isocyanate (NCO) content in the range of 22 to 24 is obtained. Subsequently, component B is blended and reacted in an amount in the range of 8 wt% to 12 wt% with component A at a temperature of in the range of 25 oC to 30 oC to obtain the coating composition to be applied on a substrate.
In the third aspect of the present disclosure relates to a kit for the coating composition. The kit comprising:
I. Container A containing component A in an airtight manner, wherein component A comprises:
i) a first polyol resin having hydroxyl (OH) content in the range of 1.4 to 2.0, in an amount in the range of 7 wt% to 11 wt%;
ii) a second polyol resin having hydroxyl (OH) content in the range of 3.0 to 4.0, in an amount in the range of 14 wt% to 22 wt%;
iii) a liquid carrier having moisture content in the range of 0 wt% to 0.2 wt% of the liquid carrier, in an amount in the range of 45 wt% to 55 wt%;
iv) a matting agent in an amount in the range of 3 wt% to 10 wt%;
v) a metal based catalyst in an amount in the range of 0.5 wt% to 1.5 wt%;
vi) a surface feel additive in an amount in the range of 5 wt% to 9 wt%; and
vii) a slip additive in an amount in the range of 0.1 wt% to 1 wt%.
II. Container B containing component B, in an airtight manner, wherein component B comprises:
i. hexamethylene diisocynate trimer as polyisocyanate having isocyanates (NCO) content in the range of 22 to 24, in an amount in the range of 8 wt% to 12 wt%;
wherein the weight percentages are with respect to the total weight of the coating composition.
III. Container C for housing the container A and the container B therewithin and an instruction sheet explaining how the component A has to be mixed with the component B to obtain a coating composition just before application of the coating composition on a substrate, which is in need of a coating composition.
DETAILED DESCRIPTION
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details, are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
The present disclosure provides a coating composition that on its application to the surface of a substrate, cures at ambient conditions, and is capable of providing a right balance between soft touch attributes and performance, without compromising the hardness of the coating, including chemical and stain resistance. This fine balance of coating between hardness to withstand resistance to domestic stains and normal wear and tear and softness to have the haptic effect is the work of art. The composition of the present disclosure overcomes one or more drawbacks of the prior art soft feel coating composition.
The present disclosure provides a two component solvent based soft feel coating, suitably designed for wood coating application which can be cured at ambient conditions with good resistance to domestic stains like water, tea, coffee, diluted acid and soap solution.
In the present disclosure, by employing various hard and soft segments and varying their molecular weights, the coating compositions that exhibit different attributes of haptic effects and at the same time provides protection to the substrate, which includes chemical resistance and stain resistance is provided.
In a first aspect, the present disclosure provides a coating composition prepared by reacting by blending a component A and a component B.
The component A comprises:
i) a first polyol resin having hydroxyl (OH) content in the range of 1.4 to 2.0, in an amount in the range of 7 wt% to 11 wt%;
ii) a second polyol resin having hydroxyl (OH) content in the range of 3.0 to 4.0, in an amount in the range of 14 wt% to 22 wt%;
iii) a liquid carrier in an amount in the range of 45 wt% to 55 wt%;
iv) a matting agent in an amount in the range of 3 wt% to 10 wt%;
v) a metal based catalyst, in an amount in the range of 0.5 to 1.5 wt%;
vi) a surface feel additive in an amount in the range of 5 wt% to 9 wt%; and
vii) a slip additive in an amount in the range of 0.1 wt% to 1 wt%;
The component B comprises:
i. a polyisocyanate having isocyanates (NCO) content in the range of 22 to 24, in an amount in the range of 8 wt% to 12 wt%;
wherein the weight percentages are with respect to the total weight of the coating composition.
In the present disclosure, the coating composition comprises solvent based two components (2K), where a chemical reaction occurs, causing cross-linking of the molecular chains (curing) at ambient conditions with haptic effect. Polyurethane polymer is synthesized by reacting a polyisocyanate from component B and a polyol containing an active hydrogen (-OH) from component A.
The present disclosure provides for two component solvent based coating composition suitable for wood coating application at ambient conditions with good resistance to domestic stains like water, tea, coffee, diluted acid and soap solution. The coating composition of the present disclosure withstands hot an cold tack resistance for more than 7 cycles without any compromise film integrity.
In accordance with the embodiments of the present disclosure, the first polyol resin is selected from the group consisting of polycarbonate polyol, polycarbonate polyester polyol and linear aliphatic polycarbonate polyester polyol. In an exemplary embodiment, the first polyol resin is linear aliphatic polycarbonate polyester polyol based on hexane diol-1,6 e caprolactum having hydroxyl (OH) content in the range of 1.4 to 2.0. In another exemplary embodiment, the first polyol is linear aliphatic polycarbonate polyester polyol based on hexane diol-1,6 e caprolactum having hydroxyl (OH) content in the range of 1.5 to 1.9.
Typically, the amount of first polyol in the coating composition of the present disclosure is in the range of 7 wt.% to 11 wt.%. In an embodiment, the amount of the first polyol is 9 wt.%.
The linear aliphatic polycarbonate polyester polyol are used as building blocks for synthesizing cross linked polyurethane polymer.
The polycarbonate polyester polyol has medium viscosity, average molecular weight of 2000 and hydroxyl (OH) content of 1.5 - 2.5, which enables easy penetration into porous substrate like wood.
Polyol resins can form complex with themselves upon self-cross-linking or with other compounds such as polyisocyanates, owing to their co-cross-linking mechanism. Polyol resins also provide flexibility to the composition to form a polyurethane polymer film on substrates having various shapes and sizes. Poly(methyl methacrylate), are also used for making impact modifiers.
In accordance with the embodiments of the present disclosure, the second polyol resin is selected from polyester polyol, branched polyester polyol, and solvent free polyester polyol. In an exemplary embodiment, the branched polyester polyol is a branched hydroxyl (OH) bearing polyester having hydroxyl (OH) content in the range of 3.0 to 4.0. In another exemplary embodiment, the branched polyester polyol is a branched hydroxyl (OH) bearing polyester having hydroxyl (OH) content in the range of 3.2 to 3.8.
Typically, the amount of the second polyol in the coating composition of the present disclosure is in the range of 14 wt.% to 22 wt.%. In an embodiment, the amount of the second polyol is 18 wt.%.
In the present disclosure, branched and hydroxyl-bearing polyester (polyols) are used as building blocks for synthesizing cross linked polyurethane polymer.
In accordance to an embodiment of the present disclosure, the ratio of the amount of first polyol resin to the amount of second polyol resin is in the range of 1:1 to 1:3. In an exemplary embodiment, the ratio is 1:2.
Typically, the liquid carrier used in the coating composition of the present disclosure is at least one selected from Butyl acetate and ortho xylene. In an embodiment, the butyl acetate is having moisture content up to 0.2 wt.%. In another embodiment, the liquid carrier is combination of butyl acetate and ortho xylene in the ratio of 60:40.
The amount of liquid carrier is in the range of 45 wt.% to 55 wt.%. In an exemplary embodiment, the amount is 50.8 wt.%.
In accordance with the embodiment of the present disclosure, the matting agent is amorphous silica. In an exemplary embodiment, the matting agent is synthetic amorphous silica having an average particle size in the range of 7 - 10 µm, pore volume (H2) 1.8 ml/g, and carbon content of 6.0 - 9.0 %.
The amount of matting agent is in the range of 3 wt.% to 10 wt.% of the total weight of the composition. In an embodiment, the amount is 4 wt.%.
Use of amorphous silica particles as matting agent improves the resistance to household chemicals and imparts soft feel to the surface.
In accordance with the present disclosure, the metal based catalyst is dibutyl tin laurate.
The amount of the metal based catalyst is in the range of 0.5 to 1.5 wt%. In an exemplary embodiment, the amount of catalyst used is 1 wt.%.
Metal based catalyst is used to increase the rate of chemical crosslinking reaction.
In accordance with the embodiment of the present disclosure, the surface feel additive is a dispersion of an oxidized high density polyethylene (HDPE).
The amount of the surface feel additive is in the range of 5 wt.% to 9 wt%. In an exemplary embodiment, the amount is 7 wt.%.
HDPE wax imparts hardness and smoothness to the coating composition in order to provide softness to the surface.
In accordance with the embodiment of the present disclosure, the slip additive is used. In an embodiment, the slip additive is polyether modified polydimethoxysilane.
The amount of the the slip additive is in the range of 0.1 wt.% to 1 wt%. In an exemplary embodiment, the amount is 0.2 wt.%.
Polyether-modified polydimethylsiloxane helps in increasing the slip or mar resistance by reducing the surface tension of the cured film.
In accordance with the present disclosure, component B of the coating composition is a polyisocyanate having isocyanates (NCO) content in the range of 22 to 24. In an embodiment, the polyisocyanate is hexamethylene diisocyanate trimer.
The amount of the polyisocyanate is in the range of 8 wt.% to 12 wt.%. In an exemplary embodiment, the amount is 10 wt.%
Hexamethylene diisocyante trimer polyisocyanate from the component B imparts maximum softness to the film matrix due to easy distortion of cyclic isocyanate at faster drying rate. The polyisocyanate, is in an amount in the range of 8 to 12 wt% of the total composition to ensure maximum crosslinking.
When components A and B are blended and reacted together, mixture of polyols in the component A reacts with the polyisocynate in the component B and allowed to cross link and cure at an ambient temperature prior to the application. The reaction of mixture of polyols from component A and polyisocyanates from component B of the present disclosure produces polyurethane polymer based coating composition.When component A and B are mixed together, chemical reaction between mixture of polyols and polyisocyanate leads to the cross-linking of the molecular chains (curing) at ambient conditions with haptic effect.
Curing and drying is carried out at ambient conditions inspite of presence of HDPE wax for surface softness.
The use of an appropriate soft feel additive like synthetic wax, a matting agent and their proper orientation in the polyurethane polymer results into soft touch at the surface.
The solvent based two component composition is applied on chemically and morphologically uneven compositional substrate like wood to give an effect of soft feel in a single coat.
The present disclosure provides a two component solvent based coating composition suitable for wood coating application capable of curing at an ambient conditions with good resistance to domestic stains like water, tea, coffee, diluted acid and soap solution. The coating composition of the present disclosure withstands hot and cold tack resistance for more than 7 cycles without compromising on film integrity.
In an embodiment, the coating composition is prepared by reacting by blending a component A and component B.
The component A comprises:
i) a first polyol resin having hydroxyl content in the range of 1.4 to 2.0, in an amount in the range of 7 wt% to 11 wt%;
ii) a second polyol resin having hydroxyl content in the range of 3.0 to 4.0, in an amount in the range of 14 wt% to 22 wt%;
iii) butyl acetate as a liquid carrier, in an amount in the range of 45 wt% to 55 wt%;
iv) amorphous silica as a matting agent in an amount in the range of 3 wt% to 10 wt%;
v) dibutyl tin dibutyl laurate as a catalyst, in an amount in the range of 0.5 to 1.5 wt%;
vi) a dispersion of an oxidized high density polyethylene (HDPE) wax as a surface feel addtive in an amount in the range of 5 wt% to 9 wt%; and
vii) polyether-modified polydimethylsiloxane as a slip additive in an amount in the range of 0.1 wt% to 1 wt%.
The component B comprises
hexamethylene diisocyanate trimer as a polyisocyanate having isocyanates (NCO) content in the range of 22 to 24, in an amount in the range of 8 wt% to 12 wt%;
wherein the weight percentages are with respect to the total weight of the coating composition.
In an exemplary embodiment, the composition is prepared by reacting by blending
component A comprising:
i) linear aliphatic polycarbonate polyester polyol based on hexane diol-1,6 e caprolactum, as a first polyol resin having hydroxyl (OH) content in the range of 1.5 to 1.9, in an amount of 9 wt%;
ii) branched (OH) bearing polyester, as a second polyol resin having hydroxyl (OH) content in the range of 3.2 to 3.8, in an amount of 18 wt%;
iii) butyl acetate having moisture content upto 0.2 wt%, in an amount of 50.8 wt%;
iv) amorphous silica in an amount of 4 wt%;
v) dibutyl tin dilaurate in an amount of 1 wt%;
vi) dispersion of an oxidized high density polyethylene (HDPE) wax in an amount of 7 wt%; and
vii) polyether-modified polydimethylsiloxane in an amount of 0.2 wt%;
wherein the weight ratio of the first polyol to the second polyol is 1:2.
component B comprising
i. hexamethylene diisocynate trimer as a polyisocyanate having isocyanates (NCO) content in the range of 22 to 24, in an amount of 10 wt%.
wherein the weight percentages are with respect to the total weight of the coating composition.
In accordance with the some of the embodiments of the present disclosure, the coating composition includes a predetermined quantity of thinner to adjust the viscosity the coating compositions. In embodiments of the present disclosure, the thinner is a combination of butyl acetate and ortho xylene in a ratio in the range of 70:30 to 50:50. In an exemplary embodiment, the ratio is 60:40.
In accordance with the some of the embodiments of the present disclosure, the viscosity of the coating composition after addition of the thinner is in the range of 30 to 54 centipoise.
In accordance with the embodiments of the present disclosure, the composition is applied on a wooden substrate followed by curing at a temperature in the range of 25 oC to 30 oC.
In a second aspect, the present disclosure relates to a process for preparing a coating composition.
The process comprises a preparation of component A, by mixing a first polyol resin having hydroxyl (OH) content in the range of 1.4 to 2.0, a second polyol resin having hydroxyl (OH) content in the range of 3.0 to 4.0, and a liquid carrier under stirring to obtain a mixture. A matting agent is added to the mixture to obtain a dispersion. A pre-determined quantity of a slip additive, a surface feel additive, a metal based catalyst are mixed with the dispersion to obtain a component A.
Next, a component B comprising a polyisocyanate having isocyanate (NCO) content in the range of 22 to 24 is obtained.
Component B is blended and reacted in an amount in the range of 8 wt% to 12 wt% with component A at a temperature of 25 oC to 30 oC to obtain the coating composition to be applied on a substrate.
In accordance with some of the embodiments of the present disclosure, the process includes step of addition of a predetermined quantity thinner to adjust the viscosity of the coating compositions. Further, the coating composition was aged after addition of said thinner. In an exemplary embodiment of the present disclosure, the thinner is added during the step of blending and reacting the component A and the component B. In another exemplary embodiment, the thinner is added to the after the step of blending and reacting component A and component B.
In accordance with the embodiments of the present disclosure, the thinner is at least one selected from butyl acetate and ortho xylene. In an embodiment, the thinner is a combination of butyl acetate and ortho xylene having a ratio in the range of 70:30 to 50:50. In another embodiment, the thiner is acombination of butyl acetate and ortho xylene having a ratio of 60:40.
The coating composition is applied to a wooden substrate and is allowed to cure at an ambient condition, to obtain a substrate having a soft feel.
In accordance to an embodiment of the present disclosure, the ratio of the amount of first polyol resin to the amount of second polyol resin is in the range of 1:1 to 1:3. In an exemplary embodiment, the ratio is 1:2.
In accordance with the embodiments of the present disclosure, the weight ratio of the polyol resin to the matting agent is in the range of 8:1 to 6:1. In an exemplary embodiment, the ratio is 6.75:1.
After curing, the coating on the wooden substrate has an enhanced chemical resistance due to highly crosslinked polyurethane linkage formed between hydroxyl groups of polyester and polycarbonate resin and NCO group of polyisocyanate at 1:0.7 to 1:1.3 mole ratio.
The composition of the present disclosure is a two component system where each of the components, Component A and Component B, are separately packed in containers. Such packing is usually made of tin. As Component A and Component B both, being very reactive in nature, they are mixed in given ratio and suitable amount of the thinner is added just before the application to tune the viscosity of the coating composition as per the required for the film formation on the substrate.
In accordance with the embodiments of the present disclosure, the substrate is wooden substrate.
In the third aspect of the present disclosure, a kit for the coating composition is provided. The kit comprising:
I. Container A containing component A in a airtight manner, wherein component A comprises:

i) a first polyol resin having hydroxyl (OH) content in the range of 1.4 to 2.0, in an amount in the range of 7 wt% to 11 wt%;
ii) a second polyol resin having hydroxyl (OH) content in the range of 3.0 to 4.0, in an amount in the range of 14 wt% to 22 wt%;
iii) a liquid carrier having moisture content in the range of 0 wt% to 0.2 wt% of the liquid carrier, in an amount in the range of 45 wt% to 55 wt%;
iv) a matting agent in an amount in the range of 3 wt% to 10 wt%;
v) a metal based catalyst in an amount in the range of 0.5 wt% to 1.5 wt%;
vi) a as surface feel additive in an amount in the range of 5 wt% to 9 wt%; and
vii) a slip additive in an amount in the range of 0.1 wt% to 1 wt%.
II. Container B containing component B, in a airtight manner, wherein component B comprises:
i. a polyisocyanate trimer having isocyanates (NCO) content in the range of 22 to 24, in an amount in the range of 8 wt% to 12 wt%;
wherein the weight percentages are with respect to the total weight of the coating composition.
III. Container C for housing the container A and the container B therewithin and an instruction sheet explaining how the component A has to be mixed with the component B to obtain the coating composition just before application of the coating composition on a substrate, which is in need of the coating composition.
In accordance with the embodiments of the present disclosure, the instruction sheet provides instructions for mixing every 1 part of the component B with 7-11 parts of the component A and blending the components A and the component B to form a homogeneous blend to be applied as the coating composition on said substrate.
In accordance with the embodiments of the present disclosure, the kit includes container D containing a thinner which can be added to the homogeneous blend to alter its viscosity.
In accordance with the embodiments of the present disclosure, the thinner comprising a combination of butyl acetate and ortho xylene in a ratio in the range of 70:30 to 50:50. In an embodiment, the ratio is 60:40.
In accordance with the embodiments of the present disclosure, the kit includes a spatula for blending the components.
In accordance with the embodiments of the present disclosure, containers A, B, C and D are made of tin.
In accordance with some of the embodiments of the present disclosure, the kit for the coating composition of the present application can readily applied at the point of application. Both, Component A and Component B, being very reactive in nature, they are mixed in given ratio and suitable amount of the thinner is added just before the application to tune the viscosity of the coating composition as per the required for the film formation on the substrate.
In accordance with the embodiments of the present disclosure, the substrate is a wooden substrate.
Advantages of the coating composition of the present disclosure:
The compositions of the prior art are largely based on water based Polyurethane dispersions (PUDs) cured by forced drying for attaining hardness. The advantage of the present disclosure is based on the solvent based chemistry of blend of polyols and an isocyanate that is cured at ambient condition which also provides better durability of the coating.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not be construed for limiting the scope of the present disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS:
Preparation of Component A:
Comparative example 1: Preparation of component A1 based on Acrylic polyol resin. (only one polyol is use and not the mixture)
57 wt.% Acrylic polyol resin having hydroxyl (OH) content between 2.4 to 3, as first polyol (second polyol not used in this Example), was mixed with 17.8 wt.% butyl acetate- ortho xylene mixture (60:40) as liquid carrier, under stirring in a stainless steel vessel. The mixture was stirred using cowl disc stirrer for 10 minutes with tip speed of 9 – 11 m/s, to obtain a thinned mixture. Wax treated synthetic amorphous silica (Syloid ED 50, 7 wt%) was mixed with thinned mixture in the vessel at a slow rate to obtain a dispersion. The tip speed was maintained at 9 – 11 m/s to achieve smooth finish. Finish of minimum 5.5 was obtained on Hegmann gauge. Polyether-modified polydimethylsiloxane (0.2 wt%) as slip additive, and dibutyl tin dilaurate (1 wt%) as catalyst, were added to the dispersion to obtain Component A1.
Comparative example 2: Preparation of component A2 based on aliphatic polycarbonate polyester resin. (only one polyol is use and not the mixture)
The Component A2 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.5 to 1.9): 64 wt.%
ii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 17.8 wt.%
iii) Wax treated silica (Syloid ED 50): 7 wt.%
iv) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
v) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Comparative example 3: Preparation of component A3 based on branched polyester resin. (only one polyol is use and not the mixture).
The Component A3 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) Branched polyester polyol (hydroxyl content 3.5) : 57 wt.%
ii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 24.8 wt.%
iii) Wax treated silica (Syloid ED 50): 7 wt.%
iv) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
v) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Comparative example 4: Preparation of component A4 based on solvent free polyester polyol resin. (only one polyol is use and not the mixture).
The Component A4 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) solvent free polyester polyol (hydroxyl content 3.5) : 57 wt.%
ii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 24.8 wt.%
iii) Wax treated silica (Syloid ED 50): 7 wt.%
iv) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
v) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Comparative example 5: Preparation of component A5 (mixture polyols used, ratio of first polyol to second is 1:1)
The Component A5 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) First polyol- Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.7): 15 wt.%
ii) Second polyol- Branched polyester polyol (hydroxyl content - 3.5) : 15 wt.%
iii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 51.8 wt.%
iv) Wax treated silica (Syloid ED 50): 7 wt.%
v) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
vi) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Comparative example 6: Preparation of component A6 (mixture polyols used, ratio of first polyol to second is 2:1)
The Component A6 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) First polyol- Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.7): 18 wt.%
ii) Second polyol- Branched polyester polyol (hydroxyl content -3.5) : 9 wt.%
iii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 54.8 wt.%
iv) Wax treated silica (Syloid ED 50): 7 wt.%
v) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
vi) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Comparative example 7: Preparation of component A7 (mixture polyols used, ratio of first polyol to second is 3:1)
The Component A7 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) First polyol- Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.7): 21 wt.%
ii) Second polyol- Branched polyester polyol (hydroxyl content -3.5) : 7 wt.%
iii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 53.8 wt.%
iv) Wax treated silica (Syloid ED 50): 7 wt.%
v) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
vi) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Comparative example 8: Preparation of component A8 (mixture polyols used, ratio of first polyol to second is 1:2)
The Component A8 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) First polyol- Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.7): 9 wt.%
ii) Second polyol- Branched polyester polyol (hydroxyl content -3.5) : 18 wt.%
iii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 54.8 wt.%
iv) Wax treated silica (Syloid ED 50): 7 wt.%
v) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
vi) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Comparative example 9: Preparation of component A9 (Use of non wax treated silica)
The Component A9 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) First polyol- Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.7): 9 wt.%
ii) Second polyol- Branched polyester polyol (hydroxyl content -3.5) : 18 wt.%
iii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 54.8 wt.%
iv) Non wax treated fumed silica: 7 wt.%
v) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
vi) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Comparative example 10: Preparation of component A10 (Replacement of the silica by HDPE based wax)
The Component A10 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) First polyol- Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.7): 9 wt.%
ii) Second polyol- Branched polyester polyol (hydroxyl content -3.5) : 18 wt.%
iii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 54.8 wt.%
iv) a dispersion of an oxidized high density polyethylene (HDPE) wax: 7 wt.%
v) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
vi) Dibutyl tin dilaurate as a metal based additive: 1 wt.%.

Comparative example 11, 13 : Preparation of component A11, A13 (Use of Untreated silica and HDPE wax in a ratio 1:1)
The Component A11 and A13 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) First polyol- Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.7): 9 wt.%
ii) Second polyol- Branched polyester polyol (hydroxyl content -3.5) : 18 wt.%
iii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 53.8 wt.%
iv) a dispersion of an oxidized high density polyethylene (HDPE) wax: 4 wt.%
v) non treated fumed silica: 4 wt.%
vi) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
vii) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Comparative example 12 : Preparation of component A12 (Use of Fischer Tropsch wax instead of HDPE based wax)
The Component A12 was prepared in a similar manner as that of component A1 except following ingradients were used:
i) First polyol- Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.7): 9 wt.%
ii) Second polyol- Branched polyester polyol (hydroxyl content -3.5) : 18 wt.%
iii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 53.8 wt.%
iv) Fischer Tropsch wax : 4 wt.%
v) non treated fumed silica: 4 wt.%
vi) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
vii) Dibutyl tin dilaurate as a metal based additive: 1 wt.%

Examples according to the present disclosure: Preparation of component A14, A15: The Component A14 and A15 were prepared in a similar manner as that of component A1 except following ingradients were used:
i) First polyol- Linear aliphatic polycarbonate polyester polyol (based on hexane diol 1, 6 E with hydroxyl content 1.7): 9 wt.%
ii) Second polyol- Branched polyester polyol (hydroxyl content -3.5) : 18 wt.%
iii) Butyl acetate- ortho xylene mixture (60:40) as liquid carrier: 50.8 wt.%
iv) a dispersion of an oxidized high density polyethylene (HDPE) wax: 7 wt.%
v) amorphous silica having average particle size in the range of 7 - 10 µm, pore volume (H2) 1.8 ml/g, and carbon content of 6.0 - 9.0 %: 4 wt.%
vi) Polyether-modified polydimethylsiloxane as slip additive: 0.2 wt.%
vii) Dibutyl tin dilaurate as a metal based additive: 1 wt.%
Component B: :
Comparative examples B1-B11: Hexamethylene diisocynate biuret with 255 equivalent weight and 16±0.5 NCO content was used as Component B.
Comparative examples B12-B13: Hexamethylene diisocynate trimer having functionality of 3.8, with 380 equivalent weight and 11±1 NCO content was used as Component B.
Examples B14-B15: Hexamethylene diisocynate trimer having functionality of 3.6, with 185 equivalent weight and 23±0.5 NCO content was used as Component B.
Thinner: Combination of butyl acetate and ortho-xylene in the ration of 60:40.
Preparation of two component coating composition:
Comparative example C1: Preparation of composition C1.
Component A1 (90 g) and Component B1 (10 g), were mixed to form a coating composition. Prior to the application, the thinner was added to the coating composition to adjust the viscosity to 15 – 20 sec using Ford cup or B4 cup viscometer (FCB4) i. e 30-54 centipoise. The coating composition was allowed to mature for 10 minutes prior to the application.
Comparative Examples C2-C13: Preparation of Composition C2 to Composition C15:
Composition C2 to Composition C13 were prepared according to the process comparative example C1, except that the corresponding components A (A2-13) were mixed with corresponding components B (B2-b13) to obtain the corresponding coating compositions C (C2-C13).
Examples according to present disclosure - C14 and C15: Preparation of Composition C14 and C15:
Composition C14 and C15 were prepared according to the process of Experiment C, Example C1, except that that the component A14 was mixed with component B14 to obtain the coating compositions C14 and component A15 was mixed with component B15 to obtain the coating compositions C15.
Procedure for coating a wooden substrate with the coating composition of the present disclosure:
Veneer panel having moisture content between 15 -25% was sanded using a sand paper (No. 120) to even out the rough surface and create surface profile for coating application. The two components A and B were mixed to obtain a coating composition and a thinner is added so as to have a viscosity between 15 – 20 seconds, measured using FCB4. The coating composition was applied using air assisted spray gun to ensure proper atomization of the composition. The panel was coated to deposit ~125 micron wet film thickness (W.F.T.) per coat on a clear sealed/ primed surface. Two coats were applied at an interval of 16 hours to obtain a two component polyurethane coated veneer panel. The coated panel was tested for soft feel effect and the toughness of the coating on the panel. Coating composition C1 to C15 were coated on the panel and the results are presented in Table-1.
Table-1: Component A1-A15, and Component B1-B15, used for preparing respective Component C1-C15.
Component A
Component B (Amount)

Hexamethylene diisocynate
Coating
Composition
(Results)
Coating composition First Polyol

(parts by weight) Second Polyol

(parts by weight) Liquid carrier

(parts by weight) Surface feel additive

(HDPE polyethylene wax) (parts by weight) Slip additive

(Polyether modified polydimethyl siloxane) Matting Agent

(parts by weight) Catalyst

(dibutyl tin dilaurate)
C1 Acrylic polyol (57 wt%) - 24.8wt % 0.2 wt% 7 wt%
(wax treated) 1 wt% B1 (10 wt%)
biuret Composition C1

Very hard film
C2 Linear aliphatic polycarbonate polyester (64 wt%) - 17.8 wt% 0.2 wt% 7 wt%
(wax treated) 1 wt% B2
(10 wt%)
biuret
Composition C2

Very tough film without any softness

C3 - Branched hydroxyl-bearing polyester (57 wt%) 24.8 wt% 0.2 wt% 7wt%
(wax treated) 1 wt% B3
(10 wt%)
biuret
Composition C3

Very rubbery film without any undulation and had non uniform appearance

C4 - Solvent free polyester polyol (57 wt%) 24.8 wt% 0.2 wt% 7 wt%
(wax treated) 1 wt% B4
(10 wt%)
biuret Composition C4

Film cured partially leading to residual tack

C5 Linear aliphatic polycarbonate polyester (15 wt%) Branched hydroxyl-bearing polyester (15 wt%) 51.8wt% 0.2 wt% 7 wt%
(wax treated) 1 wt% B5
(10 wt%)
biuret Composition C5

Hard film
C6 Linear aliphatic polycarbonate polyester (18 wt%) Branched hydroxyl-bearing polyester (9 wt%) 54.8 wt% 0.2 wt% 7wt%
(wax treated) 1 wt% B6
(10 wt%)
biuret Composition C6

Low degree of film softness but no surface smoothness and softness observed

C7 Linear aliphatic polycarbonate polyester (21 wt%) Branched hydroxyl-bearing polyester (7 wt%) 53.8 wt% 0.2 wt% 7wt%
(wax treated) 1 wt% B7
(10 wt%)
biuret Composition C7

Very hard film
C8 Linear aliphatic polycarbonate polyester (9 wt%) Branched hydroxyl-bearing polyester (18 wt%) 54.8 wt% 0.2 wt% 7 wt% 1 wt% B8
(10 wt%)
biuret Composition C8

Soft film but no surface softness and smoothness

C9 Linear aliphatic polycarbonate polyester (9 wt%) Branched hydroxyl-bearing polyester (18 wt%) 54.8 wt% 0.2 wt% 7
wt%
(non treated) 1 wt% B9
(10 wt%)
biuret Composition C9

Excellent surface softness but limited smoothness, marginal film softness

C10 Linear aliphatic polycarbonate polyester (9 wt%) Branched hydroxyl-bearing polyester (18 wt%) 54.8 wt% 7 wt% 0.2 wt% 0 wt% 1 wt% B10
(10 wt%)
biuret Composition C10

Good surface smoothness and softness and marginal improvement in film softness

C11 Linear aliphatic polycarbonate polyester (9 wt%) Branched hydroxyl-bearing polyester (18 wt%) 53.8 wt% 4 wt% 0.2 wt% 4 wt%
(non treated) 1 wt% B11
(10 wt%)
biuret Composition C11

Good surface smoothness and softness but not film softness as whole

C12 Linear aliphatic polycarbonate polyester (9 wt%) Branched hydroxyl-bearing polyester (18 wt%) 53.8 wt% 4 wt%
(Fisher tropsh wax was used instead of HDPE) 0.2 wt% 4 wt%
(non treated) 1 wt% B12
(10 wt%)
Trimer
Composition C12

Residual tack and poor surface softness
C13 Linear aliphatic polycarbonate polyester (9 wt%) Branched hydroxyl-bearing polyester (18 wt%) 53.8wt% 4 wt% 0.2 wt% 4 wt%
(non treated) 1 wt% B13
(10 wt%)
Trimer Composition C13

Residual film tack
C14 Linear aliphatic polycarbonate polyester (9 wt%) Branched hydroxyl-bearing polyester (18 wt%) 53.8 wt% 7 wt% 0.2 wt% 4 wt%
1 wt% B14
(7 wt%)
Trimer Composition C14

Excellent surface smoothness and softness

C15 Linear aliphatic polycarbonate polyester (9 wt%) Branched hydroxyl-bearing polyester (18 wt%) 50.8 wt% 7 wt% 0.2 wt% 4 wt%
1 wt% B15
(10 wt%)
Trimer
Composition C15

Excellent surface smoothness. High degree of film softness and toughness

It is evident from the table 1 that the coating composition of the present disclosure (composition C15) comprising the following blend of polyols and an isocyanates (see Table-2), can be cured at ambient conditions with better durability of the coating and provides soft feel to the surface of the coated substrate.
Table-2: Coating composition of the present disclosure
Coating composition of the present disclosure
Component A
Ingredients PBW
Linear aliphatic polycarbonate polyester (First polyol) 9
Branched hydroxyl-bearing polyester (Second polyol) 18
Butyl acetate (Liquid carrier) 50.8
HDPE Wax (Soft feel additive) 7
Matting agent 4
Polyether modified polydimethyl siloxane (Slip additive) 0.2
Dibutyl tin dilaurate (Catalyst) 1
Component B
Hexamethylene diisocynate trimer 10
TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a two component coating composition:
? provides soft feel to the surface of the coated substrate;
? can be cured at ambient conditions;
? has longer durability; and
? is economical.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveals the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.