A water- thinnable polyester resin suitable for use in paint or varnish materials and a method for its production

Abstract

The invention relates to a polyester resin with high film release properties, high heat resistance and water-thinnability, especially for electrical coils of motors and generators, heat-resistant decorative coatings, water-based paint and varnish systems for cookware.

Description

[0001] A WATER- THINNABLE POLYESTER RESIN SUITABLE FOR USE IN PAINT OR VARNISH MATERIALS AND A METHOD FOR ITS PRODUCTION

[0002] Technical Field

[0003] The invention relates to a polyester resin having high film release properties, high heat resistance and water-thinnability (water dilutability) for water-based paint and varnish materials for particularly electrical coils of motors and generators, heat-resistant decorative coatings cookware, and a method for producing the same.

[0004] In another aspect, the invention relates to a water-based paint or varnish obtained from a polyester resin having water-soluble properties, especially suitable for use in electrical coils of engines and generators, heat-resistant decorative coatings, cookware.

[0005] Prior Art

[0006] Since engines, generators and cooking appliances are exposed to high temperatures during operation, they are often coated with thermally stable and highly resistant resin-based coating materials. The specific task of these coatings is to ensure that the elements and coils in these devices remain intact even when their temperature rises. In addition, the coatings used for such heat resistance are expected to be able to maintain their mechanical properties at high temperatures.

[0007] In the relevant technical field, resins are used as thermally stable and high-strength coating materials. As coating materials that provide these properties, solvent-based polyester resins, solvent-free silicone resins or resins in emulsion form are used.

[0008] In the state of the art, solvent-based polyester resins are known to have disadvantages such as not being environmentally friendly, being flammable, effects on human health, application difficulties on surfaces such as rough surfaces and long drying times.

[0009] Solvent-free silicone resins are known to have disadvantages such as application difficulties, long drying times, low adhesion properties.

[0010] In the relevant technical field, efforts are ongoing to develop coating materials that provide thermal stability and mechanical strength at high temperatures and do not cause high VOC emissions for the environment and human health. Experts in the relevant technical field foresee that instead of solvent-based paints, coating materials used for high thermal and mechanical resistance should be developed with low VOC emissions, improved adhesion and flexibility, and curable properties at low temperatures.

[0011] Brief Description Of The Invention

[0012] In the relevant technical field, it is known that apparatus or devices such as electrical coils of engines and generators operating at high temperatures, heat-resistant decorative coatings, cookware are coated with coating materials with high film release properties and high heat resistance. Paint or varnish materials used in the coating of such apparatus and devices generally contain solvent-based polyester resins, solvent-free silicone resins or emulsion forms as raw materials. The paint or varnish materials obtained with these resins have some disadvantages compared to each other, such as high VOC emissions, low adhesion, curing at long times and temperatures, low flexibility, and difficulties in applying to surfaces. The present inventors provide a polyester resin for paint or varnish materials that provides thermal and mechanical resistance for apparatus and devices operating at high temperatures for the relevant technical field. As is known in the art, the raw materials that provide the main properties of paint or varnish materials are resin formulations. The present invention relates to the production of water-thinnable (water dilutability) polyester resins suitable for use in paint or varnish materials.

[0013] The primary object of the invention is to provide a method for obtaining a polyester resin suitable for use as a raw material in paint or varnish materials and having low VOC emissions compared to solvent-based polyester resins.

[0014] Another primary object of the invention is to provide a method for obtaining a polyester resin suitable for use as a raw material in paint or varnish materials and more flexible than solvent- free silicone resins and with other possible auxiliary resins in the paint formulation.

[0015] Another primary object of the invention is to provide a method for obtaining a polyester resin suitable for use as a raw material in paint or varnish materials and having high mechanical and chemical resistance compared to resins in emulsion form.

[0016] Detailed Description Of The Invention

[0017] In this detailed description, the subject matter of the invention relates to a polyester resin suitable for use as a raw material in paint or varnish materials, and is described only by way of non-limiting examples for a better understanding of the subject matter. The paint or varnish material referred to in the invention is a coating material, especially for electrical coils of engines and generators, heat-resistant decorative coatings, cookware. The main feature desired from the coating material in question is that it has a water-based formulation. For this purpose, the present invention provides a polyester resin which can be diluted with water and provides the desired properties for the coating materials in question.

[0018] In this respect, the present invention relates essentially to the production of polyester resin for paint or varnish materials. As known in the art, polyester resins are thermosetting resins and are frequently used in coating materials due to their good thermal and mechanical strength at high temperatures. In the relevant technical field, polyester resins are known to have disadvantages, such as the fact that they often contain solvents or VOCs and are therefore harmful to the environment.

[0019] The primary objective of the present inventors is to reduce the VOC values of paint or varnish materials and thus to have a feature compatible with human-environmental health. Accordingly, it has been determined that the polyester resin to be used as raw material in the paint or varnish materials to be obtained should be dilutable with water (water-thinnable).

[0020] The polyester resin to be obtained in the present invention contains free acidic functional groups. In this way, the polyester resin can be water dilutable (water-thinnable) for water-based paint or varnish materials. During the production of paint or varnish materials, polyester resin with water-thinning properties can enter into neutralization reaction with at least one base according to the targeted pH value. The neutralizable polyester resin can produce water-based varnish or paint formulations.

[0021] For this purpose, the polyester resin of the invention is expected to have an acid value in the specified mg / KOH range. In the present invention, the acidity value determined for polyester resin is in the range of 35 to 55 mgKOH / g. Polyester resin with these acidity values can be neutralized with at least one amine to be added during the production of paint or varnish material and can be provided in a form that can be diluted with water.

[0022] Based on the information provided herein, the first process of the present invention is the production of a polyester resin having an acidity value in the range of 35 to 55 mgKOH / g.

[0023] Synthesis of polyester resins with high acid value

[0024] At least one polybasic acid and at least one polyhydric alcohol are subjected to esterification reactions at a temperature between 200 and 250cC. The water obtained as a result of the reaction is removed from the reaction medium. Before this reaction is carried out, the molar amount of at least one polyhydric alcohol should be greater than the other reactant, at least one poly basic acid, in order to increase the chemical reaction efficiency. In the present invention, at least one reactant selected from the group consisting of citric acid, isophthalic acid, adipic acid, phosphoric acid, boric acid, glutamic acid is used as a polybasic acid for the production of polyester resin. In a preferred embodiment, more than one reactant selected from the group consisting of citric acid, isophthalic acid, adipic acid, phosphoric acid, boric acid, glutamic acid may be used as polybasic for the production of polyester resin. In a most preferred embodiment, a mixture of isophthalic acid and adipic acid is used as a reactant in the production of polyester resin as polybasic acid.

[0025] In the present invention, at least one reactant selected from the group consisting of glycol, glycerin, sorbitol, xylitol, mannitol, trimethylol propane, neopentyl glycol is used as polyhydric alcohol for the production of polyester resin. In a preferred embodiment, more than one reactant selected from the group consisting of glycol, glycerin, sorbitol, xylitol, xylitol, mannitol, trimethylol propane, neopentyl glycol may be used as polyhydric alcohol for the production of polyester resin. In one of the most preferred applications, a mixture of trimethylol propane and neopentyl glycol is used as a reactant in the production of polyester resin as polyhydric alcohol.

[0026] In order to carry out esterification reactions at targeted stoichiometric ratios, at least one polybasic acid reactant in an amount of 25 to 65 wt% and at least one polyhydric alcohol in an amount of 35 to 75 wt% of the polyester resin chain to be obtained is added to the reaction medium.

[0027] In a most preferred embodiment, for the production of polyester resin, the reaction medium comprises 20 wt% to 40 wt% of isophthalic acid and 5 wt% to 25 wt% of adipic acid as polybasic acid, 25 wt% to 45 wt% of trimethylol propane and 10 wt% to 30 wt% of neopentyl glycol as polyhydric alcohol. For said esterification reaction, the mixture is first heated to a temperature of 180 to 190 O, where it is kept for at least 1 hour. Subsequently, the temperature of the reaction medium is increased to a value between 200 and 250 'C and the esterification reaction kinetics in the reaction medium is increased. The acidity value of the polyester resin obtained for the waiting time at this temperature is controlled. The target acidity value is between 5 and 12 mgKOH / g.

[0028] After reaching this value, the temperature of the reaction medium is adjusted to a value between 180 and 190cC. After reaching this temperature, at least one of Trimellitic anhydride, ethyl acid anhydride, propionic acid anhydride, methyl acetate anhydride is added to the reaction medium to obtain polyester resin with high acidity value. The compound that will provide the high acidity value mentioned here is added to the reaction medium at a value between 5% and 15% by weight depending on the amount of polyester resin to be obtained. The wt% of the mentioned acid is determined according to the targeted high acidity polyester resin. At the same reaction medium temperature, the reaction is continued until the acidity value of the polyester resin obtained is 35 to 55 mgKOH / g. The reaction is continued at the same temperature and the reaction medium is cooled when the acidity value reaches a value between 35 and 55 mgKOH / g. When the temperature of the reaction medium reaches 100cC, glycol derivatives or ether derivatives are added as water-soluble solvents to bring the volumetric solid content of the synthesized resin to the desired ratio. The amount of water soluble solvent in question is added at a value between 50% and 75% by weight of the amount of solid polyester resin to be obtained.

[0029] The water obtained during this process is continuously removed from the reaction medium.

[0030] After this process step, polyester resin with high acidity value can be obtained.

[0031] In this invention, polyester resin with high acidity is modified with silicone to provide additional technical properties. The aim of this process is to provide additional chemical, mechanical and thermal resistance properties for water-thinnable polyester resin. In the invention, this is referred to as silicone modification. The amount of silicone resin is variable so that the water-thinnable polyester resin has the targeted thermal and / or mechanical strength. In addition, the amount of silicone resin may vary depending on the amount of water-thinnable polyester resin to be obtained.

[0032] Water-thinnable polyester resin modified with silicone resins has a more flexible structure and is more compatible with possible auxiliary resins in the paint formulation and can be cured at lower temperatures thanks to the ester functional groups in its structure compared to solvent-free silicone resins.

[0033] Modification of the obtained water-thinnable polyester resins with silicone resin

[0034] The polyester resin subject to the invention is modified with silicone resins. The silicone resin preferably comprises at least one of hydroxyl, methoxy or ethoxy functional groups and also methyl-phenyl functional groups.

[0035] The modification process is preferably carried out at a temperature of between 120 and 150cC.

[0036] A silicone comprising at least one of hydroxyl, methoxy or ethoxy functional groups as well as methyl-phenyl functional groups is added to the reaction medium at a value in the range of 20% to 40% by weight of the amount of polyester resin in the reaction medium. In this range of values, targeted silicone modification processes are possible.

[0037] At least one catalyst is used for silicone modification processes. Preferably at least one titanate- based compound is used as said catalyst. The catalyst is added to the reaction medium in an amount not exceeding 3% by weight of the added silicone resin. This value is preferred in order to keep the reaction rate under control as targeted and to keep the stability of the final product under control.

[0038] The silicone modification process step is continued until the condensation reaction ends with the formation of water, methanol or ethanol, which can be a by-product depending on the silicone resin used. Accordingly, the duration of the silicone modification process is in the range of 2 to 8 hours.

[0039] The polyester resin obtained in this invention can be used as raw material in many technical fields. In particular, the inventors state that it can be used as raw material for electrical coils of engines and generators, heat-resistant decorative coatings, water-based paint and varnish systems for cookware. Apart from these areas, the use of polyester resin with the aforementioned configuration as a raw material may offer obvious solutions for the relevant technical field.

[0040] In another aspect, the invention relates to the use of polyester resin having a high acidity value, with or without silicone modification, as a raw material for paint or varnish materials. Accordingly, the polyester resin having a high acidity value can be diluted with water (water thinnable). This is achieved by neutralizing the high acidity polyester with at least one base.

[0041] Neutralization of polyester resins with high acidity so that they can be diluted with water

[0042] In this process step, the polyester resin chain with an acid value in the range of 35 to 55 mgKOH / g is neutralized. In this process step, the polyester resin chain is expected to react with at least one base. Preferably, at least one amine-based compound is used in this invention. In this invention, at least one of methylamine, ethylamine, aniline, triethylamine, trimethylamine, diethanolamine group can be preferably selected as amine-based basic compound.

[0043] After the polyester resin has an acid value of 35 to 55 mgKOH / g, it is expected to react with at least one base in order to be in a water thinnable form, which is the next process. In this invention, at least one amine-based compound is used as a base. In this invention, preferably at least one of methylamine, ethylamine, aniline, triethylamine, trimethylamine, diethanolamine group can be selected as amine-based basic compound.

[0044] During the production of paint or varnish materials subject to the invention, the water-thinnable polyester resin subject to the invention reacts with at least one crosslinker and is subjected to crosslinking processes. In this invention, melamine resins are preferably used as crosslinkers. Melamine is added at a value between 5% and 30% by weight of the polyester resin. Between these values, melamine can exhibit the target crosslinking properties. Water-based paint or varnish materials containing water-thinnable polyester resin subject to the invention have lower VOC emissions than solvent-based polyester resin-containing paint or varnish materials commonly used in the technique due to the embodiments contained therein.

[0045] The water-based paint or varnish materials containing water-thinnable polyester resin subject to the invention are more flexible and compatible with other possible auxiliary resins in the paint formulation than the paint or varnish materials containing solvent-free-based polyester resin commonly used in the technique due to the embodiments contained therein.

[0046] Water-based paint or varnish materials containing water-thinnable polyester resin subject to the invention are more flexible and compatible with other possible auxiliary resins in the paint formulation than solvent-free-based paint or varnish materials containing polyester resin, which are commonly used in the technique, thanks to the arrangements it contains.

[0047] The water-thinnable polyester resin subject to the invention will pave the way for the production of environmentally friendly solutions in paint systems by reducing VOC emissions due to the fact that it can be thinned with water thanks to the embodiments it contains. The paint formulation prepared with water-thinnable silicone-modified polyester resin has stronger mechanical and chemical resistance compared to emulsion form resins since it can be used as oven cured with strong cross-linking with the melamine resins it contains.

[0048] In addition, water-thinnable polyester resin provides advantages over solvent-free silicone resins used for heat resistance, such as the ability to adjust the flexibility due to the polyester chain in its structure, more compatibility with other possible auxiliary resins in the paint formulation and the possibility of curing at lower temperatures. The curing temperature is the temperature required for the resin to form a dry film on the surface where the paint and / or varnish system is applied. The curing temperature and curing time of the resin subject to the invention may vary between 150-170 'C and 30-45 mi nutes.

[0049] The scope of protection of the invention is set out in the appended claims and cannot be strictly limited to what is described in this detailed description for the purpose of illustration. This is because it is clear that a person skilled in the art can come up with similar constructions in the light of the above without departing from the main theme of the invention.

Claims

CLAIMS1. The invention is a method for the production of a polyester resin suitable for use as a raw material in paint or varnish materials, in particular for electrical coils of motors and generators, heat-resistant decorative coatings, paints or varnish materials for coating cookware characterized by comprising the following process steps that make it water- thinnable: enabling at least one polybasic acid and at least one polyhydric alcohol to undergo an esterification reaction in a reaction medium, the temperature of the reaction medium referred to herein must first be between 180 and 190 O and kept in this temperature range f or at least 1 hour after this time, the reaction medium temperature is increased to a value between 200 and 250 O and the esterification reaction is t erminated when the acidity value of the polyester resin obtained at this temperature is between 5 and 12 mgKOH / g, Adding at least one acid with a high acidity value to the reaction medium and performing the reaction in order to increase the polyester resin with an acidity value in the range of 5 to 12 mgKOH / g to an acidity value in the range of 35 to 55 mgKOH / g, addition of at least one of trimellitic anhydride, ethylic acid anhydride, propionic acid anhydride, methyl acetate anhydride as the acid with high acidity value mentioned herein, the reaction temperature referred to here is between 180 and 190cC,Cooling the polyester resin, which reaches an acidity value in the range of 35 to 55 mgKOH / g, to 100 O and adding one of the water-solu ble glycol or ether-based compounds to the reaction medium at this temperature.

2. The method according to claim 1 , characterized in that; at least one selected from the group consisting of citric acid, isophthalic acid, adipic acid, phosphoric acid, boric acid, glutamic acid is added as said polybasic acid.

3. The method according to any one of the preceding claims, characterized in that; at least one selected from the group consisting of glycol, glycerin, sorbitol, xylitol, mannitol, trimethylol propane, neopentyl glycol is added as said polyhydric alcohol.

4. The method according to any one of the preceding claims, characterized in that; at least one polybasic acid is added to the reaction medium in an amount of 25% to 65% by weight of the polyester resin chain to be obtained.

5. The method according to any one of the preceding claims, characterized in that; at least one polyhydric alcohol is added to the reaction medium in an amount of 35% to 75% by weight of the polyester resin chain to be obtained.

6. The method according to claims 4-5, characterized in that; isophthalic acid in an amount of from 20% to 40% by weight and adipic acid in an amount of from 5% to 25% by weight as polybasic acid; trimethylol propane in an amount of from 25% to 45% by weight and neopentyl glycol in an amount of from 10% to 30% by weight as polyhydric alcohol are added to the reaction medium.

7. The method according to any one of the preceding claims, characterized in that the amount of at least one acid having a high acidity value added to the reaction medium is in the range of 5 to 15 wt%.

8. The method according to any one of the preceding claims, characterized in that said polyester resin having an acidity value between 35 and 55 mgKOH / g obtained at the end of the process is subjected to modification with a silicone-based compound.

9. The method according to claim 8, characterized in that; said silicone-based compound preferably comprises a methyl-phenyl functional group and at least one of hydroxyl, methoxy or ethoxy functional groups and.

10. The method according to any one of claims 8-9, characterized in that; said silicone- based compound in said silicone-modified reaction is added to the reaction medium in an amount of between 20 and 40 wt%.

11. The method according to any one of claims 8-10, characterized in that; at least one titanate-based compound is added as a catalyst.

12. The method according to claim 11 , characterized in that; said at least one titanate- based catalyst is added to the reaction medium in an amount of not more than 3% by weight of the amount of the silicon-based compound.

13. A method for producing a paint or varnish using polyester resin having an acidity of 35 to 55 mgKOH / g obtained by a method according to any one of the preceding claims and characterized by comprising the following process steps; subjecting polyester resin with an acidity value of 35 to 55 mgKOH / g to neutralization reactions with at least one amine-based compound; and crosslinking processes by adding at least one crosslinking compound to the resulting mixture.

14. The method according to claim 13, characterized in that; said neutralization process uses at least one selected from the group consisting of methylamine, ethylamine, aniline, triethylamine, trimethylamine, diethanolamine as an amine-based compound.

15. The method according to any one of claims 13-14, characterized in that ; melamine is added as said crosslinking compound.

16. The method according to claim 15, characterized in that; said crosslinking compound is added to the reaction medium in an amount of between 5 to 30% by weight of the amount of polyester resin.

17. A water-thinnable polyester resin having an acidity value in the range of 35 to 55 mgKOH / g, obtained by a method according to any one of claims 1-7.

18. A water-thinnable silicone-modified polyester resin having an acidity value in the range of 35 to 55 mgKOH / g obtained by a method according to any one of claims 8-12.

19. A water-based paint or varnish obtained by a method according to one of claims 13-16.