US-20260125512-A1 - WATER SOLUBLE CO-POLYESTER

Abstract

The present invention discloses a water soluble co-polyester precursor comprising: (a) at least one dicarboxylic acid or ester thereof; (b) at least one diol; and (c) at least dimethyl sulfoisophthalate (DMSIP) or isophthalic acid sulfonate (SIPA) having a weight percentage in the range of 0 to 20 wt % or 0 to 18% trimellitic anhydride. The water-soluble co-polyester of the present invention has an excellent solubility in hot water at low-temperature. The water soluble co-polyester precursor can be used in the films or coatings which can be then used to form top coats that exhibit good resistance to scratches and solvents, and improved ink adhesion, improved metallic bonding strength and image quality.

Inventors

• Balasundaram Dillyraj
• CHANDRAKANT OMKAR VYAS
• Gokal KUMAR
• F. Louis JOSEPH
• Gaurav Ojha
• Ravindra Chandra SHARMA

Assignees

• ESTER INDUSTRIES LIMITED

Dates

Publication Date

20260507

Application Date

20240216

Priority Date

20230217

Claims (17)

1. 1 . A water soluble co-polyester precursor comprising: a. at least one dicarboxylic acid or ester thereof, b. at least one diol; and c. at least dimethyl sulfoisophthalate (DMSIP) or isophthalic acid sulfonate (SIPA) having weight percentage in the range of 0 to 20 wt % or 0 to 18% trimellitic anhydride
2. 2 . The co-polyester precursor as claimed in claim 1 , wherein said dicarboxylic acid is selected from aromatic and/or aliphatic acid the group consisting of terephthalic acid, isophthalic acid, 2,6-napthalene dicarboxylic acid, 3,4′-diphenyl ether dicarboxylic acid, hexahydrophthalic acid, 2,7-naphthalenedicarboxylic acid, phthalic acid, 4,4′-methylenebis(benzoic acid), oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, 3-metyhladipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,11-undecanedicarboxylic acid, 1,10-decanedicarboxylic acid, undecanedioic acid, 1,12-dodecanedicarboxylic acid, hexadecanedioic acid, docosanedioic acid, tetracosanedioic acid, dimer acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,1-cyclohexanediacetic acid, fumaric acid, maleic acid, and hexahydrophthalic acid.
3. 3 . The co-polyester precursor as claimed in claim 1 , wherein said diol is selected from the group consisting of mono ethylene glycol (MEG), diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, dimer diol, (cis, trans) 1,4-cyclohexanedimethanol, di(ethylene glycol), tri(ethylene glycol), poly(ethylene ether) glycols, poly(butylene ether) glycols, branched diols, hexane diol or combinations or derivatives thereof.
4. 4 . The co-polyester precursor as claimed in claim 1 , where ratio of DIMSIP/SIPA may vary 0 to 20 wt % or 0 to 18 weight % Trimellitic anhydride.
5. 5 . The co-polyester precursor as claimed in claim 1 , wherein the dicarboxylic acid is terephthalic acid having 80 to 90 mol % based on the acid content.
6. 6 . The co-polyester precursor as claimed in claim 1 , wherein the dicarboxylic acid is isophthalic acid having 10 to 20 mol % based on the acid content.
7. 7 . The co-polyester precursor as claimed in claim 1 , wherein the diol is 1, 6 hexane diol having 20 to 25 mol % based on the diol content, and wherein the remainder diol proportion comprises said ethylene glycol.
8. 8 . The co-polyester precursor as claimed in claim 1 , wherein the water soluble co-polyester has a melting point between 80 to 180° C.
9. 9 . The co-polyester precursor as claimed in claim 1 , wherein the water soluble co-polyester has a glass transition temperature of above 45° C.
10. 10 . The co-polyester precursor as claimed in claim 1 , wherein the water soluble co-polyester has a melt flow index, measured according to ASTM D 1238 at 265° C., less than 80 gm/10 min.
11. 11 . The co-polyester precursor as claimed in claim 1 , wherein the water soluble co-polyester are in chips/pellets/Powder/flakes form.
12. 12 . The co-polyester precursor as claimed in claim 1 , wherein in the water soluble co-polyester, a polymer IV can be adjusted in melt polymerization from 0.300 dl/g to 0.500 dl/gm.
13. 13 . The co-polyester precursor as claimed in claim 1 , wherein the water soluble co-polyester has minimum Dv (Surface Tension) value of 56 after film coating.
14. 14 . The co-polyester precursor as claimed in claim 1 , wherein a Resin Coated A4 size Film after Boiling-½ an hour pass ink test and Dye shade test is used for measuring film coating efficiency.
15. 15 . The co-polyester precursor as claimed in claim 1 , wherein a Resin Coated A4 size Film, First Ink & Dye Coating Then Boiling water pass ink test and Dye shade test is used for measuring film coating efficiency.
16. 16 . The co-polyester precursor as claimed in claim 1 , wherein the composition optionally comprises an additional diol selected from the group consisting of diethylene glycol 0 to 20 mol %, 0 to 25 mol % 2-Methyl-1,3-propanediol, 0 to 30 mol % Neopentyl glycol based on the diol content, wherein the remainder diol proportion comprises said ethylene glycol.
17. 17 . A film comprising the water soluble co-polyester as claimed in claim 1 .

Description

FIELD OF THE INVENTION The present invention relates to the field of water-soluble co-polyester. Particularly, the present invention relates to a water-soluble co-polyester having an excellent solubility in hot water at low-temperature. It can be used as an adhesive based on a high glass transition temperature (Tg) and it has better surface tension properties. The films or coatings made by using present invention's co-polyester can be used to form top coats that exhibit good resistance to scratches and solvents, and improved ink adhesion, improved metallic bonding strength and image quality. These features make the co-polyester of the present invention a special grade for flexible packaging especially for pasturisable/retortable liquid packaging. BACKGROUND OF THE INVENTION Aqueous coating compositions of a resinous thermoplastic coating material (clear coat) such as thermoplastic, (meth)acrylic or (meth)acrylic-styrene copolymer in the form of emulsions are well known in the printing industry. In today's world, wherein Climate change and its prevention is one of the sustainable goals of UN it is important that use of organic solvents is restricted and such a product is made for which water can be used as a solvent and the product can be used for various industrial purposes. For example, a reference is made to Japanese Patent Laid-Open No. Hei9-296100 that discloses an aqueous dispersion of polyester resin obtained by dispersing polyester resin with an acid value of 10 to 40 mg KOH/g and a weight average molecular weight of 9,000 or higher in an aqueous medium, and it is described that a coating film excellent in properties such as processability and solvent resistances can be produced using such an aqueous dispersion. Similarly, another reference is made to U.S. Pat. No. 5,384,160 that provides a method for depositing an aqueous coating composition onto an ink layer or uninked surface in a printing process. Yet another reference is made to U.S. Pat. No. 6,818,699 that provides an aqueous dispersion of polyester resin that can be used as a coating agent for a variety of substrates and is capable of forming a high-quality polyester resin coating film with a high adhesion strength, but if the dispersion is stored for a long duration, the molecular weight of the polyester resin tends to be lowered. Therefore, it is probable to cause a problem of deterioration of the properties. Thus, there continues a need in the art for water soluble co-polyester which has improved properties and can be used in various industries. SUMMARY OF THE INVENTION An object of the present invention is to develop a water-soluble co-polyester with improved surface tension and adhesion. Another object of the invention is to develop a water-soluble co-polyester based on terephthalic acid, isophthalic acid and aliphatic diols. Yet another object of the invention is to provide a method of manufacturing the water-soluble co-polyester which can be produced in pellet, flake, powder or liquid form. Further another object of the invention is to provide water soluble co-polyester having excellent solubility in hot water at low-temperature which can be used as an adhesive and has better surface tension properties. Another object of the present invention is to provide water soluble co-polyester films or coatings that can be used to form top coats that exhibit good coating composition. Yet another object of the present invention is to provide a water-soluble co-polyester which can be used as a coating to improve one or more than one surface properties of polyester films. The surface properties that are improved can be selected from but are not limited to improved surface tension, adhesion, printing, metallizing properties and/or glossiness of the film. Still further object of the present invention is to provide a water-soluble co-polyester that can be used directly as a coating by dissolving it in water without the use of any other organic or inorganic solvent. Another object of the invention is to provide a water-soluble co-polyester that can be used to form top coats that exhibit good resistance to scratches and solvents, and improved ink adhesion and image quality. Further another object of the invention is to provide water soluble co-polyester that has increased bond strength and improved dyne values that leads to efficient printing and the printed matter is not wiped off. The co-polyester of the present invention has improved surface tension, adhesion, bond strength, dyne value, resistance and solubility in water making its applications wide in the field of packaging. DETAILED DESCRIPTION Definition of Terms For convenience, before further description of the present invention, certain terms employed in the specification, examples and appended claims are collected here. These definitions should be read in light of the remainder of the disclosure and understood as by a person of skill in the art. Unless defined otherwise, all technical and scient