A synthesis method of BIO-based isosorbide derivative epoxy resin

Abstract

The present invention relates to a method for synthesizing a bio-based isosorbide derivative epoxy resin which is safe in terms of the environment and worker health. By means of the inventive method, isosorbide derivative-based epoxy resin is obtained without the need for high temperature and pressure and without the extra step of washing with organic solvent. With this method, the temperatures used in epoxy resin synthesis are reduced and energy is used efficiently.

Description

[0001] A SYNTHESIS METHOD OF BIO-BASED ISOSORBIDE DERIVATIVE EPOXY RESIN

[0002] Technical Field

[0003] The present invention relates to a method for synthesizing a bio-based isosorbide derivative epoxy resin which is safe in terms of the environment and worker health.

[0004] Background of the Invention

[0005] Epoxy resins are polymers that harden as a result of an exothermic reaction and exhibit strong adhesion and durability properties. These resins generally consist of two components: the primary component is the epoxy resin, and the secondary component is the hardener. The most widely used hardener material in the production of epoxy resins is Bisphenol A (BP A) and its derivatives. Bisphenol A causes problems for all living things by spreading into the soil, water and atmosphere and endangers the lives of some animal species. Bisphenol A is harmful to human health and also to the environment. Studies show that BPA may cause infertility. Bisphenol A may disrupt hormonal balance by increasing oestrogen levels by acting like oestrogen hormone in the body. This in turn adversely affects the reproductive, nervous, immune, metabolic and cardiovascular systems by preventing the endocrine system from functioning properly. Endocrine disruptors such as BPA are known to disrupt normal reproductive and thyroid function, as well as interfere with the way vitamin D works in the body. Due to the adverse effects of BPA on health and the environment, especially on the endocrine system, it is important to develop biobased alternatives [1], Isosorbide is a monomer obtained from plant sources and has low toxicity. Isosorbide offers environmentally friendly and safer alternatives in terms of health by being used in the synthesis of bio-based epoxy resins. However, the synthesis of isosorbide-based epoxy resins is carried out in the high temperature range. When the mixture obtained as a result of the reaction is filtered, it is washed with some environmentally unfriendly organic solvents. This process causes adverse environmental impacts due to the use of environmentally unfriendly solvents. The methods used for removing solvents increase energy consumption and lead to additional costs. The non-transparency of the obtained products limits the usage areas of the resin and causes difficulties in achieving the desired properties in terms of transparency and epoxy values [2],

[0006] In the article titled “Synthesis and Properties of Isosorbide-Based Epoxy Resin”, the synthesis and properties of isosorbide-based epoxy resins by using isosorbide and freshly distilled epichlorohydrin are addressed. In the process specified in the article, isosorbide and epichlorohydrin were reacted by being heated to boiling temperature (115-117°C) and then the reaction was completed by adding NaOH. At this stage, water was removed from the medium. After the reaction was completed, the mixture in the form of sludge was filtered and the remaining precipitant was washed several times with acetone. However, this process increases the amount of solvent and is considered as an environmentally unfriendly method. Then, the volatile components need to be removed by using a rotary evaporator under reduced pressure. The product obtained as a result of the reaction was described as a light yellow, viscous and water-soluble liquid. Being yellow in color may limit the usage areas of the resin. While the targeted epoxy number for isosorbide diglycidyl ether was 0.77 mol / 100 g, the epoxy number obtained as a result of the synthesis was determined as 0.44 mol / 100 g. This shows that the method operates with low yield, and the product is not of the expected purity. This result shows that the product with the expected transparency and epoxy value could not be obtained, and the method should be improved [3], The Korean patent document no. KR20160010133, an application included in the state of the art, has carried out a detailed characterization of an isosorbide-based epoxy resin and demonstrated that this resin has mechanical properties comparable to commercial bisphenol A-based resins. In the said patent, the synthesis of epoxy resin using bio-based epichlorohydrin (ECH) and isosorbide is detailed. After the reaction is completed, filtrate filtration process is applied and excess ECH is recovered. However, in this process, reaching high temperatures and using organic solvents such as acetone, which can harm the environment, create adverse environmental and health impacts.

[0007] In conclusion, the drawbacks and limitations of existing methods necessitate the development of alternative methods for synthesizing bio-based isosorbide epoxy resins which are environmentally friendly and have low toxicity.

[0008] Summary of the Invention

[0009] The invention aims to eliminate the disadvantages of existing methods for synthesizing bio-based isosorbide derivative epoxy resins which are safe in terms of the environment and worker health, and to develop a method which provides additional advantages.

[0010] The primary object of the invention is to provide a synthesis method which is cost-effective and reduces energy consumption. The synthesis of isosorbide- or its derivative-based epoxy resins is carried out without the use of high temperatures. The fact that high temperatures are not used both makes the production process more cost-effective and reduces energy consumption.

[0011] Another object of the invention is to provide an environmentally friendly synthesis method which reduces toxic damage to the environment. In the invention, the washing process is carried out without using organic solvents in the reaction process. Organic solvents used in conventional methods are harmful both to the environment and to health, therefore, the present invention reduces environmental impacts by avoiding such solvents.

[0012] A further object of the invention is to provide a synthesis method for producing epoxy resin which does not harm human health and has high strength.

[0013] By means of the present invention, a method which is carried out at low temperature and does not require washing with organic solvents is developed. These properties reduce energy consumption and minimize environmental damage. Energy efficiency reduces costs while at the same time reducing adverse impacts on the environment and providing a more sustainable production process.

[0014] Description of the Figures

[0015] Figure 1. Graphic showing glossmeter measurements on glass surfaces.

[0016] Figure 2. Graphic showing glossmeter measurements on metal surfaces.

[0017] Figure 3. Contact angle test results.

[0018] Figure 4. Crosscut test results.

[0019] Detailed Description of the Invention

[0020] The present invention provides a method for synthesizing isosorbide derivativebased epoxy resin in order to achieve all of the aforementioned objects which will become apparent from the detailed description below.

[0021] The synthesis method of an isosorbide derivative-based epoxy resin comprises the process steps of: i. purifying the reactor at the temperature of 30-60°C from ambient gases by introducing inert gas into it; ii. stirring the isosorbide derivative and epichlorohydrin by loading them into the reactor; iii. increasing the reactor temperature to 40-100°C; iv. dosing by adding base solution to the reactor and then continuing to stir the obtained mixture in the reactor; v. filtering the final mixture under vacuum by filter paper; vi. separating the final mixture into infranatant and supernatant in a separatory funnel after filtration; vii. obtaining an isosorbide-based epoxy resin by removing the supernatant containing isosorbide derivative-based epoxy resin from the solvent by rotary technique.

[0022] The inert gas mentioned in the said method is nitrogen gas. Here, the mole ratio of isosorbide derivative:epichlorohydrin is 1 :3-1 :8. The residence time for phase separation in the separatory funnel is 10-16 hours. The excess solvent remaining in the mentioned supernatant is removed under vacuum at 90-130°C in a rotary device.

[0023] In one embodiment of the invention, the reactor temperature is increased to 50- 70°C. As a result of synthesis attempts at different temperatures, it was observed that the desired physical appearance and chemical properties were obtained within the indicated temperature range. As a result of the conducted optimization studies, it was observed that the desired physical appearance and chemical properties could not be obtained outside the indicated temperature range. The desired epoxy equivalent weight (EEW) is directly related to the yield of the reaction and as the yield increases, the target EEW value is reached. Carrying out the reaction at temperatures outside these ranges causes problems such as yellowing of the color, cloudiness in the resin or failure to reach the desired EEW value. As a result of testing different temperature parameters, it was observed that this temperature range provided the most yielding result and the desired resin in terms of characterization and appearance was obtained in this temperature range. In the preferred embodiment of the invention, the isosorbide derivative is isosorbide granules.

[0024] In another embodiment of the invention, the mentioned reactor is a jacketed reactor.

[0025] In another embodiment of the invention, an inert gas inlet is connected to the reactor in order for the reaction medium to be purified from ambient gases and a reflux arrangement is added in order to prevent the solvent from escaping from the medium.

[0026] In another embodiment of the invention, the mentioned base solution is an NaOH solution of 50%. Here, the ratio of NaOH:isosorbide derivative is 2: 1-2,5: 1 by mole. Dosing duration is 150-300 minutes. In the inventive method, the use of an NaOH solution of 50% and the ratio of NaOH:isosorbide derivative being 2:1- 2,5: 1 by mole enable the desired product to be obtained in a more effective way by increasing the yield of the reaction. By means of the dosing duration being 150-300 minutes, there is no need for reaching high pressures and high temperatures. In turn, this prevents energy consumption.

[0027] In another preferred embodiment of the invention, the salts in the infranatant and the supernatant are separated by filtering them with the aim of increasing the purity of the resin. The salt released during the reaction prevents accurate measurement of the EEW value of the resin. For this reason, it is aimed to pass the salt to the infranatant and remove it from the resin by phase separation method. Water is released during the reaction, and this water is incompatible with the structure of the resin. Since water adversely affects the performance in epoxy applications, water should not be present in the system. For this purpose, phase separation method is preferred, and the formed water and salt are removed from the resin. In order to minimize the damage to the environment, the dissolution and separation of salts in the water phase reduces the energy consumption in the filtration process of the process and is preferred with the aim of reducing the environmental damage of the process.

[0028] The said method involves the reaction of isosorbide and epichlorohydrin in an alkaline medium. The isosorbide derivative compound is shown below (Formula

[0029] Formula I

[0030] Rl : -CsHi?, -C9H19, -C10H21, -C11H23, -C12H23, -C13H25, -C14H27, -C15H29, -C16H31, -C17H33, -C18H35, -OH

[0031] R2: -CsHn, -C9H19, -C10H21, -C11H23, -C12H23, -C13H25, -C14H27, -C15H29, -C16H31, -C17H33, -C18H35, -OH

[0032] Here, Rl may be a C8-C18 alkyl or -OH group; R2 may be a C8-C18 alkyl group or an OH group. In a preferred embodiment of the invention, at least one of the mentioned Rl and R2 is a hydroxyl (-OH) group.

[0033] The preferred structure in order to obtain the best yield from the reaction is the one in which both R1 and R2 functional groups are hydroxyl (-OH) groups. The structure of the isosorbide molecule containing two hydroxyl groups is given below (Formula II): Formula II

[0034] The inventive epichlorohydrin, on the other hand, is an organic compound with the chemical formula of C3H5CIO. Its chemical structure contains an oxirane ring (epoxide group) as well as a chlorine and a hydroxyl group. The epichlorohydrin used in the inventive method is obtained by using glycerin, a natural raw material.

[0035] The general synthesis reaction mechanism of an isosorbide molecule according to the invention with epichlorohydrin in an alkaline reaction medium is shown below (Reaction I):

[0036] Reaction I

[0037] The inventive method comprises the addition of epichlorohydrin to isosorbide derivatives in an alkaline medium. By means of the inventive method, isosorbide derivative-based epoxy resin is obtained without the need for high temperature and pressure and without the extra step of washing with organic solvent. With this method, the temperatures used in epoxy resin synthesis are reduced and energy is used efficiently. As a result of using an NaOH solution of 50%, determining the stoichiometric ratios and optimizing the durations of the reaction steps in the inventive method, there is no need for reaching high pressure and high temperatures in the process. The separation of water and salt released during the reaction by phase separation method reduces the energy used in the process. At the same time, a large portion of the salt is also separated from the resin, which reduces the adverse environmental impact of the step of washing with solvent. The isosorbide derivative-based epoxy resin obtained by the inventive method was cured as a film for 16 hours at 30°C by using polyether amine and isophorone diamine hardeners. As a result of this curing, tests were carried out in order to compare it with BPA-based resin cured under the same conditions. As a result of contact angle, appearance, viscosity, glossmeter, crosscut and ultraviolet (UV) resistance tests, it was found that Bisphenol A (BPA)-based resin and isosorbide- based resin showed very close performance characteristics.

[0038] 100 micrometer films of BPA-based epoxy resin and isosorbide-based epoxy resin were applied on glass and metal surfaces and cured with curing agent. Four glass and metal surfaces were coated with BPA / Polyether amine, Isosorbide / Polyether amine, BPA / Isophorone diamine and Isosorbide / Isophorone diamine. Measurements were carried out on a total of 8 surfaces. All films were taken with a hand applicator at a scale of 100 micrometers. As a result of the measurements carried out on metal and glass surfaces at 20°, 60° and 85° with a glossmeter device, results of the 85° measurement were taken into consideration. The final results were noted by averaging 3 measurements carried out at this degree. In the results of this test, it is seen that the isosorbide-based epoxy resin exhibits similar gloss and surface appearance performance to the BPA-based resin (Figure 1 and Figure 2). The results of the measurement carried out on metal and glass surfaces at 85° with a glossmeter device are shown in Table 1 and Table 2.

[0039] Table 1. Results of measurement carried out with a glossmeter on the glass surface (85°)

[0040] Coating on Glass Surface Average Values (85°)

[0041] BPA / Polyether Amine 103,6

[0042] Isosorbide / Polyether Amine 108,6

[0043] BPA / Isophorone diamine 101,6

[0044] Isosorbide / Isophorone diamine 106,3 Table 2. Results of measurement carried out with a glossmeter on the metal surface (85°)

[0045] Coating on Metal Surface Average Values (85°)

[0046] BPA / Polyether Amine 99,4

[0047] Isosorbide / Polyether Amine 97

[0048] BPA / Isophorone diamine 98,9

[0049] Isosorbide / Isophorone diamine 95,5

[0050] The contact angle test results are shown in Table 3.

[0051] Table 3. Contact angle test results

[0052] Contact Angle Right angle Left Angle

[0053] BPA / Poly ether Amine 62,69 60,73

[0054] Isosorbide Epoxy - Polyether Amine 53,37 53,23

[0055] BPA - Isophorone diamine 72,09 73,02

[0056] Isosorbide Epoxy - Isophorone diamine 59,63 59,53

[0057] BPA molecules are organic compounds and are connected by a methyl group between two phenyl rings in their chemical structure. Due to the effect of the phenyl rings and the methyl group, the BPA molecule shows limited solubility with water and is hydrophobic. BPA contains many carbon-hydrogen and carbonoxygen bonds in its structure. Due to the phenyl rings it contains, it is partially apolar and therefore has limited solubility with water. According to these reasons, it can be said that BPA exhibits hydrophobic properties in general. Isosorbide has two hydroxyl groups (-OH) in its structure. The arrangement of hydrogen and oxygen atoms in the structure provides isosorbide with polar molecular properties and causes it to exhibit good solubility with water. Isosorbide is in hydrophilic structure and dissolves well with water by means of hydroxyl groups that can form hydrogen bonds. BPA- and isosorbide-based epoxy resins cured with polyether amine were filmed and contact angle tests were performed on these films. It is seen that BPA resin films cured with polyether amine exhibit more hydrophobic properties than isosorbide-based resin films with high contact angles. The fact that the films formed with BPA-based resin exhibit higher hydrophobic properties is directly related to the chemical structure of the BPA-based epoxy resin described above. BPA- and isosorbide-based epoxy resins cured with isophorone diamine were filmed and contact angle tests were performed on these films. It is seen that BPA resin films cured with isophorone diamine exhibit more hydrophobic properties than isosorbide-based resin films with high contact angles. The fact that the films formed with BPA-based resin exhibit higher hydrophobic properties is directly related to the chemical structure of the BPA-based epoxy resin described above. In the contact angle results of both resins, it is seen that the contact angles of the films cured with isophorone diamine have higher values, that is, they exhibit more hydrophobic properties. The reason for this can be explained by the chemical structure of the curing agents. The amount of methyl per gram of isophorone diamine being high and its being in cyclic structure provides more hydrophobic properties to the films formed compared to polyether amine and supports the hydrophobic properties of the resins. The values of isosorbide-based epoxy resin and BPA-based epoxy resin synthesized under optimized conditions are shown in Table 4.

[0058] Table 4. Isosorbide-based epoxy resin and BPA-based epoxy resin values

[0059] The crosscut test is a standardized test method used to evaluate the adhesion durability of coating materials. This test measures adhesion strength by creating crosscuts made with sharp blades. The results help to determine how strongly the material adheres to the sub-surface. The crosscut test was performed by using the prepared BPA-based and isosorbide-based epoxy resins on metal surface coating films. In the results of this test, it was seen that the isosorbide-based epoxy resin performed close to the BPA-based resin in terms of surface adhesion and at the same time, the BPA-based epoxy resin coating cured with isophorone diamine hardener exhibited lower adhesion in the crosscut test results (Figure 4). The crosscut test results evaluation scale is shown in Table 5.

[0060] Table 5. Crosscut test results evaluation scale

[0061] Resin Type / Curing Agent Polyether Amine Isophorone Diamine

[0062] Hardener Hardener

[0063] BPA-based Epoxy Resin 0 2

[0064] Isosorbide-based Epoxy Resin 0 0

[0065] In one embodiment of the invention, in Experiment 1, 1 mole of isosorbide and 5 moles of epichlorohydrin are loaded into a 2000 ml jacketed reactor with a stirrer and a nitrogen inlet and stirred at 600 rpm for 30 minutes with the aim of dissolving the isosorbide in the reactor at 30°C. After 30 minutes, the reactor temperature is adjusted to 80°C. Dosing is started with 275 grams of an NaOH of 50% at 300 rpm at 80°C. NaOH is dosed in 205 minutes. At the end of dosing, it is stirred for another 20 minutes. After completion of the reaction, the obtained product is filtered through a filter paper under low pressure and kept in a separatory funnel. After 12 hours, the supernatant of the product is heated under pressure to 110°C and unreacted epichlorohydrin is recovered. The epoxy resin obtained in Experiment 1 has an epoxy equivalent weight (EEW) of 287,25 g / eq and a viscosity of 11221 cps at 25°C. The product is yellowish in color.

[0066] In another embodiment of the invention, in Experiment 2, 1 mole of isosorbide and 8 moles of epichlorohydrin are loaded into a 2000 ml jacketed reactor with a stirrer and a nitrogen inlet and stirred at 600 rpm for 30 minutes with the aim of dissolving the isosorbide in the reactor at 30°C. After 30 minutes, the reactor temperature is adjusted to 60°C. Dosing is started with 275 grams of an NaOH of 50% at 300 rpm at 60°C. NaOH is dosed in 205 minutes. At the end of dosing, it is stirred for another 20 minutes. After completion of the reaction, the obtained product is filtered through a filter paper under low pressure and kept in a separatory funnel. After 12 hours, the supernatant of the product is heated under pressure to 110°C and unreacted epichlorohydrin is recovered. The epoxy resin obtained in Experiment 2 has an epoxy equivalent weigh of 214,3 g / eq and a viscosity of 7365 cps at 25°C. The product is a transparent colored liquid.

[0067] In another embodiment of the invention, in Experiment 3, 1 mole of isosorbide and 8 moles of epichlorohydrin are loaded into a 2000 ml jacketed reactor with a stirrer and a nitrogen inlet and stirred at 600 rpm for 30 minutes with the aim of dissolving the isosorbide in the reactor at 30°C. After 30 minutes, the reactor temperature is adjusted to 75°C. Dosing is started with 275 grams of an NaOH of 50% at 300 rpm at 75°C. NaOH is dosed in 205 minutes. At the end of dosing, it is stirred for another 20 minutes. After completion of the reaction, the obtained product is filtered through a filter paper under low pressure and kept in a separatory funnel. After 12 hours, the supernatant of the product is heated under pressure to 120°C and unreacted epichlorohydrin is recovered. The epoxy resin obtained in Experiment 3 has an epoxy equivalent weigh of 283,72 g / eq and a viscosity of 33450 cps at 25°C. The product is yellowish colored liquid.

[0068] In another embodiment of the invention, in Experiment 4, 1 mole of isosorbide and 8 moles of epichlorohydrin are loaded into a 2000 ml jacketed reactor with a stirrer and a nitrogen inlet and stirred at 600 rpm for 30 minutes with the aim of dissolving the isosorbide in the reactor at 30°C. After 30 minutes, the reactor temperature is adjusted to 75°C. Dosing is started with 250 grams of an NaOH of 50% at 300 rpm at 75 degrees. NaOH is dosed in 205 minutes. At the end of dosing, it is stirred for another 20 minutes. After completion of the reaction, the obtained product is filtered through a filter paper under low pressure and kept in a separatory funnel. After 12 hours, the supernatant of the product is heated under pressure to 120°C and unreacted epichlorohydrin is recovered. The epoxy resin obtained in Experiment 4 has an epoxy equivalent weigh of 257,89 g / eq and a viscosity of 26350 cps at 25°C. The product is yellowish colored liquid.

[0069] In another embodiment of the invention, in Experiment 5, 1 mole of isosorbide and 6 moles of epichlorohydrin are loaded into a 2000 ml jacketed reactor with a stirrer and a nitrogen inlet and stirred at 600 rpm for 30 minutes with the aim of dissolving the isosorbide in the reactor at 30°C. After 30 minutes, the reactor temperature is adjusted to 55°C. Dosing is started with 262,5 grams of an NaOH of 50% at 300 rpm at 50°C. NaOH is dosed in 205 minutes. At the end of dosing, it is stirred for another 20 minutes. After completion of the reaction, the obtained product is filtered through a filter paper under low pressure and kept in a separatory funnel. After 12 hours, the supernatant of the product is heated under pressure to 120°C and unreacted epichlorohydrin is recovered. The epoxy resin obtained in Experiment 5 has an epoxy equivalent weigh of 227,2 g / eq and a viscosity of 11320 cps at 25°C. The product is yellowish colored liquid.

[0070] In another embodiment of the invention, in Experiment 6, 1 mole of isosorbide and 5 moles of epichlorohydrin are loaded into a 2000 ml jacketed reactor with a stirrer and a nitrogen inlet and stirred at 600 rpm for 30 minutes with the aim of dissolving the isosorbide in the reactor at 30°C. After 30 minutes, the reactor temperature is adjusted to 55°C. Dosing is started with 262,5 grams of an NaOH of 50% at 300 rpm at 55°C. NaOH is dosed in 205 minutes. At the end of dosing, it is stirred for another 20 minutes. After completion of the reaction, the obtained product is filtered through a filter paper under low pressure and kept in a separatory funnel. After 12 hours, the supernatant of the product is heated under pressure to 120°C and unreacted epichlorohydrin is recovered. The epoxy resin obtained in Experiment 6 has an epoxy equivalent weigh of 342,3 g / eq and a viscosity of 24100 cps at 25°C. The product is yellowish colored liquid.

[0071] Experiment 2-6 data are given in Table 6 below. Table 6. Viscosity, epoxy equivalent weight and appearance properties of the epoxy resin obtained by Experiments 2-6

[0072] The reaction temperature parameter was observed between Experiment 1 and 5 Experiment 2. When the reaction was carried out by increasing the temperature to 60°C instead of 80°C, it was observed that the reaction was carried out in a more controlled manner. The temperature at which the reaction was carried out affects the reaction rate. As a result, more oxirane rings were obtained and a lower EEW (g / eq) value was obtained. The reaction temperature parameter was observed 10 between Experiment 2 and Experiment 3. When the reaction was carried out by increasing the temperature to 75°C instead of 80°C, it was aimed to observe the sensitivity of the reaction to temperature and how it affected the results. It was observed that a temperature of 5°C did not dramatically change the EEW value resulting from the reaction. As the reaction temperature of the obtained resin 15 increased, yellowing of the resin was observed. This, in turn, showed that temperatures higher than the desired range cause color change by damaging the molecular structures. Between Experiment 3 and Experiment 4, the change caused by NaOH stoichiometry in the reaction was observed. The amount of NaOH being excessive in the reaction medium causes a reaction between isosorbide molecules instead of catalyzing the reaction between epichlorohydrin and isosorbide. This, in turn, decreases the reaction yield, reduces the number of oxirane rings and increases the EEW value. This, consequently, leads to higher density values. The parameter seen in Experiment 5 and Experiment 6 depends on the change in the amount of epichlorohydrin. As a result of the study, epichlorohydrin being present less in the reaction medium decreases the reaction yield. While this causes longer polymer chains to be formed and obtaining higher EEW values due to the scarcity of oxirane rings formed, the longer chains formed lead to an increase in the density.

[0073] References

[0074] [1] Ma, Y., Liu, H., Wu, J., Yuan, L., Wang, Y., Du, X., Wang, R., Marwa, P. W.,

[0075] Petlulu, P., Chen, X., & Zhang, H. (2019). The adverse health effects of bisphenol A and related toxicity mechanisms. Environmental Research,

[0076] 176, 108575. https: / / doi.Org / 10.1016 / j.envres.2019.108575

[0077] [2] Chrysanthos, M., Galy, J., & Pascault, J. (2011). Preparation and properties of bio-based epoxy networks derived from isosorbide diglycidyl ether. Polymer, 52(16), 3611-3620. https: / / doi.Org / 10.1016 / j.polymer.2011.06.001

[0078] [3] Lukaszczyk, J., Janicki, B., & Kaczmarek, M. (2011). Synthesis and properties of isosorbide-based epoxy resin. European Polymer Journal, 47(8), 1601— 1606. https: / / doi.Org / 10.1016 / j.eurpolymj.2011.05.009

Claims

CLAIMS1. A method for synthesizing bio-based isosorbide derivative epoxy resin that is safe in terms of the environment and worker health; characterized in that it comprises the process steps of:

1. purifying the reactor at the temperature of 30-60°C from ambient gases by introducing inert gas into it; ii. stirring the isosorbide derivative and epichlorohydrin by loading them into the reactor; iii. increasing the reactor temperature to 40-100°C; iv. dosing by adding base solution to the reactor and then continuing to stir the obtained mixture in the reactor; v. filtering the final mixture under vacuum by filter paper; vi. separating the final mixture into infranatant and supernatant in a separatory funnel after filtration; vii. obtaining an isosorbide-based epoxy resin by removing the supernatant containing isosorbide derivative-based epoxy resin from the solvent by rotary technique.

2. A method according to Claim 1; characterized in that the isosorbide derivative is an isosorbide granule.

3. A method according to Claim 1 or 2; characterized in that the mentioned base solution is a sodium hydroxide (NaOH) solution of 50%.

4. A method according to Claim 3; characterized in that the ratio of NaOH:isosorbide derivative is 2: 1-2,5: 1 by mole.

5. A method according to any one of the preceding claims; characterized in that the mentioned reactor comprises an inert gas inlet and a reflux arrangement in order to prevent the solvent from escaping from the medium.

6. A method according to any one of the preceding claims; characterized in that the mentioned reactor is a jacketed reactor.

7. A method according to any one of the preceding claims; characterized in that the mentioned inert gas is nitrogen gas.

8. A method according to any one of the preceding claims; characterized in that the reactor temperature is increased to 50-70°C.

9. A method according to any one of the preceding claims; characterized in that the mole ratio of isosorbide derivative:epichlorohydrin is 1 :3-1 :8.

10. A method according to any one of the preceding claims; characterized in that the mentioned dosing duration is 150-300 minutes.

11. A method according to any one of the preceding claims; characterized in that the residence time for phase separation in the separatory funnel is 10-16 hours.

12. A method according to any one of the preceding claims; characterized in that the excess solvent remaining in the mentioned supernatant is removed under vacuum at 90-130°C in a rotary device.

13. A method according to any one of the preceding claims; characterized in that it comprises the step of separating the salts in the infranatant and the supernatant by filtering them.

14. A bio-based isosorbide derivative epoxy resin which is synthesized by a method according to any one of the preceding claims and which is safe in terms of the environment and worker health.

15. A resin according to Claim 14 which is intended to be used in the field of coatings.

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