BIO-based isocyanate-free polyurethane foam and preparation method thereof

Abstract

The invention relates to a bio-based isocyanate-free polyurethane foam curing at room temperature and a preparation method thereof. The invention provides an isocyanate-free polyurethane foam with desirable values of tensile strength, compression strength, and adhesion strength. The invention provides a polyurethane foam that does not pose a threat to the environment and living health. The invention makes an isocyanate-free polyurethane foam that can be cured at room temperature in the range of 1 minute to 2 hours possible. The invention provides an isocyanate-free polyurethane foam without the need for additional catalysts.

Description

[0001] DESCRIPTION

[0002] BIO-BASED ISOCYANATE-FREE POLYURETHANE FOAM AND PREPARATION METHOD THEREOF

[0003] Technical Field of the Invention

[0004] The invention relates to a bio-based isocyanate-free polyurethane foam curing at room temperature and a preparation method thereof.

[0005] State of the Art

[0006] Polyurethanes are polymeric materials with versatile applications in every aspect of our daily lives. Due to their outstanding mechanical (elasticity, adhesion, hardness, durability, etc.) and physical properties, they are widely used in the production of rigid and flexible foams, elastomers, sealants, adhesives, paints, high-strength protective coatings, and biomedical materials. Depending on their composition, polyurethane foams can range in structure from soft flexible foams to rigid foams used in insulation or structural materials. Polyurethane foam serves different applications with its rigid and flexible varieties. Rigid polyurethane foam has excellent performance in thermal insulation while increasing structural durability and for these reasons rigid polyurethane foam is widely used in construction and refrigeration systems. Flexible polyurethane foam offers comfort and support and is preferred in the furniture, automotive, and textile sectors. Industrially, polyurethane foams are mostly obtained by polymerization between a polyisocyanate and a hydroxyl-terminated oligomer (polyol). Foaming is usually initiated by adding water to the formulation, and the water interacting with the reagents to produce carbon dioxide (CO2) in situ. Water triggers the hydrolysis of isocyanate, which is converted into CO2 acting as a blowing agent, and an amine that is incorporated into the growing polyurethane chains. Instead of water, other blowing agents can be used to expand and foam the polymeric matrix.

[0007] In the state of the art, polyurethane-based materials are produced from toxic isocyanates that harm the environment and living health. Under the REACH regulation, a European Union regulation that covers most end-consumer products and requires companies to report on chemicals used in their supply chain and products, industrial and professional use of isocyanate is currently heavily restricted. At the end of their life,polyurethane materials are either incinerated or placed in landfills. However, during combustion polyurethanes are degraded and hydrogen cyanide (HCN), a mainly toxic substance, is also released by the decomposing isocyanates. Global warming, limited petroleum resources, and the detrimental effects of high carbon dioxide (CO2) emissions caused by said polyurethane sources on the environment adversely affect the polyurethane market. In order to prevent the polyurethane foam market from being affected by these negative effects of isocyanate, studies on isocyanate-free polyurethane foam production have started to be carried out.

[0008] From the point of view of the mentioned concerns, although there are many methods to synthesize non-isocyanate polyurethanes (NIPU), the multiple addition reaction of multifunctional bicyclic carbonates and diamines seems to be the most promising NIPU synthesis method. In academic research, the development of polyurethane (NIPU), an environmentally friendly synthesis process that does not use isocyanates as raw materials, has been successfully carried out. The synthesized NIPU molecule was found to have a similar carbamate structure and similar performance to conventional PU.

[0009] One of the methods for the utilization of CO2in environmentally friendly industrial processes is the synthesis of cyclic carbonates, one of the basic raw materials of isocyanate-free polyurethanes, through the addition of CO2to epoxides. Since the formation of cyclic carbonate is a moderately exothermic reaction, the use of catalysts is necessary in this process. For this purpose, various catalysts such as metal and quaternary ammonium salts, ionic liquids, metal oxides, phthalocyanines, and salen complexes are preferred. Kihara et al. investigated the catalytic effect of alkali metal salts on the incorporation of CO2into epoxide and studied the effect of solvent, temperature, and pressure parameters on the activity of these catalysts. In their study, they showed that alkali metal halides exhibited the highest catalytic activity among alkali metal salts due to their favorable nucleophilicity and cleavage ability. They also reported that higher cyclic carbonate conversions were obtained with the use of dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methyl-2-pyrrolidone (NMP) solvents, whereas dimethyl sulfoxide (DMSO) solvent led to lower conversion rates due to oxidation on the catalyst. Although some studies have indicated that high CO2pressure above 20 atmospheres (atm) is required for high cyclic carbonate conversions, Kihara reported that alkali metal halides show high catalytic activity evenunder atmospheric pressure at 100 °C. However, the difficulty of recovering organic solvents such as DMF, DMAc, and NMP limits the environmental friendliness of this process.

[0010] Quaternary ammonium salts containing strong halide ions such as tetrabutylammonium bromide ((n-C4H9)4NBr) (TBAB), tetrabutylammonium iodide ((n-C4H9)4NI) are also very effective in the synthesis of cyclic carbonates. Calo et al. reported a method to synthesize cyclic carbonates from oxiranes using CO2 with molten tetrabutylammonium halides as catalysts under CO2 atmospheric pressure. They also defined the reaction behavior of TBAB as a catalyst. According to their explanation, the tetrabutylammonium ion removes the halide anion from the cation, so the electrostatic interaction between anions and cations is weakened, thus making the anion a stronger nucleophile. The nucleophilic attack reaction of the stronger halide anion allows the epoxy ring to open more easily, which causes the oxy anion to react with CO2 to convert to the corresponding cyclic carbonate.

[0011] Tamami et al. used different catalysts such as Nal, LiBr, benzyl trimethylammonium bromide, Amberlit IR 400 (Cl), and TBAB. They reported that the epoxy group of TBAB showed a higher conversion to cyclic carbonate group than others. They reported that the other catalyst was also insoluble or partially soluble, resulting in low or medium conversion (TBAB melting point 103 °C, LiBr melting point 553 °C).

[0012] Another remarkable group of catalysts are salen complexes. North et al. developed a new pair of bimetallic aluminum (salen) complex and tetrabutylammonium bromide as an active and co-catalyst for the synthesis of cyclic carbonates from terminal epoxides and CO2 at atmospheric pressure and room temperature. They declared that TBAB enables the opening of the epoxy ring through the bromide anion and the in situ generation of the tributylamine cation, which forms the carbamate salt with the addition of CO2. The bimetallic aluminum salen complex brings these two products together and allows them to combine in the molecule to complete the cycle. Although Salen-type catalysts are effective at low pressure and temperature, their use in industrial applications is still not available today due to complex synthesis procedures.

[0013] Although cyclic carbonates are usually synthesized from petroleum-based molecules such as polypropylene glycol), polyethylene glycol, and bisphenol A diglycidylether,recently carbonated vegetable oils (triglycerides) are increasingly used as raw materials for Isocyanate Free Polyurethanes. Tamami et al. first synthesized carbonated soybean oil (CSBO) containing five-membered cyclic carbonates using 5 mol% tetra-nbutylammonium bromide (TBABr) as a catalyst at 110 °C relative to epoxy. The authors also showed that CSBO can easily react with different amines to give the corresponding isocyanate-free polyurethanes at 60 °C, followed by a curing step at 100 °C for 3 hours. Bahr and Mulhaupt showed that TBABr (silica-supported 4-pyrrolidinopyridinium iodide (SiO2) with epoxidized soybean oil (ESBO) / epoxidized linseed oil (ELO) improved carbonation kinetics at CO2 pressures of 10 bar and 30 bar and found that carbonation formation was affected by pressure and catalyst type.

[0014] In the present art, the reactivity of cyclic carbonate compounds used in the production of isocyanate-free polyurethane foam is considerably lower than that of isocyanate compounds and therefore a process time of over 10 hours at a temperature of 80-120°C is required for full curing of the products. Due to the low reactivity of cyclic carbonate groups, processes such as curing etc. to obtain the final crosslinked material require high temperatures and / or long reaction times. For example, to obtain the final crosslinked material, it may be necessary to hold it at 200 °C for 30 minutes or at room temperature for 3 days. The conditions usually reported for NIPU synthesis are a hardening step at >70 °C and a post-hardening step at higher temperatures (>100 °C). Sometimes these periods even exceed 24 hours.

[0015] In the state of the art, another major challenge faced in this field is the development of a simple self-foaming system that operates at room temperature, as in conventional polyurethanes (PU). Polyurethane foams are produced using physical (solvents) and chemical (water) blowing / expanding agents. Blowing agents (physical or chemical) are mandatory components for all types of polyurethane foam. However, in studies on Non-Isocyanate Polyurethane (NIPU) based foams, studies have been limited due to the poor reactivity between cyclic carbonate and amine groups at ambient temperature. However, interest in this topic is intense. The first study to obtain polyhydroxyurethane (PHU) foam was carried out by Cornille et al. In this study, a flexible isocyanate-free polyurethane foam was produced at room temperature using trimethylolpropanetriscarbonate and poly (propyleneoxide) bis-carbonate with diamines in the presence of thiourea catalyst. In this process, poly (methylhydrogensiloxane) was used as a foaming blowing agent, releasing hydrogen during thermal decomposition. Blattmann etal. developed a flexible and biobased PHU foam using fluorohydrocarbon as blowing agent. Xuedong et al. prepared partially biobased glucose-based PHU foam using dimethyl carbonate and hexamethylenediamine in the presence of sodium bicarbonate (NaHCO3) as blowing agent. Grignard et al. produced PHU foams using biologically derived aminotelechelicoligoamide and supercritical carbon dioxide (scCO2) as blowing agents. Furthermore, Monie et al. developed an easily scalable process for self-blowing isocyanate-free polyurethane foams by adding amines and thiols to cyclic carbonates. Clark et al. succeeded in obtaining a sustainable self-foaming material with sorbitol and pentamethylenediamine without the use of isocyanates and blowing agents.

[0016] In the isocyanate-free polyurethane foam production methods of the state of the art, chemicals such as triazabicyclodecene (TBD), amine-based structures, an ionic salt or ionic liquid consisting of a combination of a cation and an anion, an organometallic catalyst and a phosphine-based catalyst, and preferably 1,8-diazabicyclo[5.4.0]undec-7-ene, tetrabutylammonium phenolate, tetrabutyl ammonium hydroxide, potassium carbonate, cesium carbonate or potassium phosphate or hydrogen phosphate are used as catalysts. Especially organometallic catalysts and catalysts containing heavy metals cause environmental pollution and pose occupational health risks. Catalysts, especially when they are specialty or rare compounds, increase the cost of production, making the overall production process more expensive.

[0017] The tensile strength, compression strength, and adhesion strength values of polyurethane foams obtained by isocyanate-free polyurethane foam production methods in the present art do not achieve desirable results. The mechanical properties of polyurethane foams such as tensile strength, compression strength, and adhesion strength are critical to the performance of the product and its success in the application field. If said values are not at the desired levels, many negativities are encountered. When the tensile strength of isocyanate-free polyurethane foams is low, tearing and fragmentation problems are easily encountered. Polyurethane foams used especially in construction and automotive applications can lose their structural integrity and pose safety risks due to their low tensile strength. Foams used as insulation or filling material can lose their functionality and reduce energy efficiency due to their low tensile strength. In polyurethane foams with low compression strength, the load carrying capacity of the foam decreases. This may cause the structural elements to lose their support strength. The adhesion strength shows how strongly the polyurethane foamcan adhere to different surfaces. This is particularly important for assembly and adhesion processes. Good adhesion of the foam to the surfaces ensures that the functional properties of the material such as sealing, insulation, and structural integrity work effectively. Low adhesion strength can cause separation or leakage over time, which adversely affects the performance of the product. The mechanical properties of tensile strength, compression strength, and adhesive strength are critical for the reliable and effective use of polyurethane foams in various application areas. Proper design and testing of these properties of foam, especially in the construction, automotive, packaging, and insulation industries, ensures that products meet quality and performance standards. In the state of the art, there is no polyurethane foam that meets said mechanical properties in a desirable way.

[0018] In isocyanate-free polyurethane foams in the state of the art, although environmental damage is tried to be minimized without the use of isocyanate, petroleum-derived materials are used as raw materials in production. The replacement of polyurethane foam production raw materials with more sustainable alternatives has become a necessity considering the environmental problem.

[0019] The isocyanate-free polyurethane foams and the production methods thereof in the present art have various limitations and inadequacies. Firstly, the processing processes that require high temperatures and long periods of time for full curing of such foams reduce production efficiency. Further, the inability to carry out the reaction without the use of additional catalysts during production with existing methods increases production costs and complexity. In addition, the inability of the foams obtained to show the desired performance in terms of mechanical properties such as tensile strength, compression strength, and adhesion strength limits the industrial applications of these foams. Even if the use of isocyanates is avoided in order to reduce environmental damage, the continued use of petroleum-derived materials as raw materials in production cannot eliminate environmental pollution and threats to living health. All these problems has made it necessary to develop a new isocyanate-free polyurethane foam that minimizes environmental impacts, has improved mechanical properties and a more efficient production process, and a method for the preparation of this foam.Summary and Objects of the Invention

[0020] The invention describes a bio-based isocyanate-free polyurethane foam curing at room temperature and a preparation method thereof. The invention provides an isocyanate-free polyurethane foam with desirable values of tensile strength, compression strength, and adhesion strength. The invention provides a polyurethane foam that does not pose a threat to the environment and living health. The invention makes an isocyanate-free polyurethane foam that can be cured at room temperature in the range of 1 minute to 2 hours possible. The invention provides an isocyanate-free polyurethane foam without the need for additional catalysts.

[0021] The invention provides an isocyanate-free polyurethane foam with desirable values of tensile strength, compression strength, and adhesion strength. A isocyanate-free polyurethane foam with desirable values of tensile strength, compression strength, and adhesion strength are provided in the invention by the combination of polyhydroxy urethanes and epoxies. Thanks to sodium silicate (water glass), an organic-inorganic bond structure is formed in the structure, resulting in a foam system that is more rigid, robust, and having high combustion resistance. The tensile strength of the polyurethane foam of the invention is 21.43 Mpa, compression strength is 42.65 Mpa, and adhesion strength is 2.096 N / mm2. When the tensile strength of isocyanate-free polyurethane foams is low, tearing and fragmentation problems are easily encountered. Polyurethane foams used especially in construction and automotive applications can lose their structural integrity and pose safety risks due to their low tensile strength. Foams used as insulation or filling material can lose their functionality and reduce energy efficiency due to their low tensile strength. The tensile strength of the polyurethane foam of the invention being 21.43 Mpa eliminates all these problems. In polyurethane foams with low compression strength, the load carrying capacity of the foam decreases. This may cause the structural elements to lose their support strength. The compression strength of the polyurethane foam of the invention being 42.65 Mpa eliminates the problems caused by said low compression strength. Low adhesion strength can cause separation or leakage over time, which adversely affects the performance of the product. The adhesion strength of the polyurethane foam of the invention being 2.096 N / mm2prevents the problems of separation or leakage over time and negative effects on polyurethane foam performance. The sodium silicate contained in the polyurethane foam of the invention increases the fire resistance of thepolyurethane foam. Water in sodium silicate is stable in the foam formation process. Foam can decompose rapidly when burning at high temperature and the water in the crystallized compound can be separated into large quantities at a certain temperature. Thus, a large amount of combustion heat can be absorbed and the surface temperature of the material is reduced; at the same time, a large amount of water vapor forms a barrier for air insulation on the surface of the foam and a flame retardant effect is achieved. Furthermore, sodium silicate is also a smoke inhibitor and forms a coating film of silicon oxide structure on the surface of a combustible material, stopping combustion by cutting off contact with oxygen and reducing the formation of smoke and toxic gases. In addition, sodium silicate also increases the mechanical strength of the polyurethane foam by forming an inorganic bond structure within the system and supports the polyurethane foam to reach the set foam structure.

[0022] Another object in the invention is to provide a polyurethane foam that does not pose a threat to the environment and living health. In a polyurethane foam invention that does not pose a threat to the environment and living health; it is ensured by not using isocyanate and minimizing carbon dioxide (CO2) emission. In the isocyanate-free polyurethane foam of the invention, cyclic carbonates, which are the main components of isocyanate-free polyurethanes, are obtained by bonding epoxies with CO2, thus minimizing CO2emissions. In the method of the invention, bio-based ring carbonate polymers are obtained by reacting epoxidized soybean with CO2and these products are bio-based in terms of structure. The epoxy contained in the structure of the polyurethane foam of the invention is obtained from soybean oil and therefore the polyurethane foam of the invention is bio-based.

[0023] The invention provides an isocyanate-free polyurethane foam that can be cured at room temperature in the range of 1 minute to 2 hours. While the ability to cure isocyanate-free polyurethane foam at room temperature is provided by the catalyzing effect of cyclic carbonates on sodium silicate systems in the invention, the ability to cure in a very short time such as 1 minute-2 hours is similarly provided by the catalyzing effect of cyclic carbonates on sodium silicate systems. Full curing times can be achieved from 2 hours to 24 hours without the need for heating. In the invention, polyhydroxy urethanes and epoxies are used in combination in order to shorten the curing process of the bio-based isocyanate-free polyurethane foam of the invention and to improve the material performance, in other words, to improve the strength andadhesion properties of polyurethane foams. Thus, isocyanate-free polyurethanes in hybrid structure are obtained. Epoxy groups react faster with amines and help the reaction to take place in a shorter time at room temperature.

[0024] The invention provides an isocyanate-free polyurethane foam without the need for additional catalysts. In the production of isocyanate-free polyurethane foam of the invention, curing was realized in short periods at room temperature thanks to the catalytic effect of cyclic carbonate on water glass (sodium silicate / water).

[0025] Description of the Drawings

[0026] Fig. 1. The overlaid FT-IR spectrum of epoxidized soybean oil and cyclic carbonate-based soybean.

[0027] Detailed Description of the Invention

[0028] The invention relates to a bio-based isocyanate-free polyurethane foam curing at room temperature and a preparation method thereof. The invention provides an isocyanate-free polyurethane foam having a tensile strength of 21.43 Mpa, a compression strength of 42.65 Mpa, and an adhesion strength of 2.096 N / mm2. The invention provides an isocyanate-free polyurethane foam that is environmentally friendly and does not pose a threat to living health thanks to not using isocyanate, minimizing carbon dioxide (CO2) emission, and obtaining bio-based ring carbonate polymers by the reaction of epoxidized soy with CO2. The invention makes an isocyanate-free polyurethane foam that can be cured at room temperature in the range of 1 minute to 2 hours possible. Full curing times can be achieved from 2 hours to 24 hours without the need for heating. The invention provides an isocyanate-free polyurethane foam without the need for additional catalysts.

[0029] The invention provides an isocyanate-free polyurethane foam that can be cured at room temperature in the range of 1 minute to 2 hours. While the ability to cure isocyanate-free polyurethane foam at room temperature is provided by the catalyzing effect of cyclic carbonates on sodium silicate systems in the invention, the ability to cure in a very short time such as 1 minute-2 hours is similarly provided by the catalyzing effect of cyclic carbonates on sodium silicate systems. Full curing times canbe achieved from 2 hours to 24 hours without the need for heating. In the invention, polyhydroxy urethanes and epoxies are used in combination in order to shorten the curing process of the bio-based isocyanate-free polyurethane foam of the invention and to improve the material performance, in other words, to improve the strength and adhesion properties of polyurethane foams. Thus, isocyanate-free polyurethanes in hybrid structure are obtained. Epoxy groups react faster with amines and help the reaction to take place in a shorter time at room temperature.

[0030] It comprises the process steps of: synthesizing soybean monomer based on cyclic carbonate:

[0031] i. adding epoxidized soybean oil and tetrabutylammonium bromide (TBAB) catalyst to the system equipped with a 500 ml three-necked flask, reflux condenser, gas inlets to provide gas entry and exit, and magnetic stirrer, and providing the mixture,

[0032] ii. sending carbon dioxide (CO2) to the system under atmospheric pressure and continuing the reaction at 110-140°C,

[0033] iii. Dissolving the resulting viscous material in ethyl acetate and then extracting three times with water followed by drying in anhydrous sodium sulfate,

[0034] iv. removing the solvent from the structure by volatilization under low pressure and obtaining cyclic carbonate based soybean.

[0035] Herein, the course of the reactions at the end of process step no. ii was followed by FT-IR analysis, the complete disappearance of the epoxy peaks at 830 cm1and the formation of a prominent cyclic carbonate peak at 1803cm1indicate that the reaction was completed and cyclic carbonate based monomer was obtained. The viscosity value of the product obtained as a result of process step no. iv was 2540 cp at 25°C and the density was measured as 1±0.05g / cm3at 25°C.

[0036] Fig. 1 shows the overlaid FT-IR spectrum of epoxidized soybean oil and cyclic carbonate-based soybean.Synthesis of cyclic carbonate-terminated hydroxyurethane prepolymer:

[0037] Cyclic carbonate-terminated hydroxyurethane prepolymers were synthesized by reacting cyclic carbonate-based soy and amine compounds with a molar equivalence ratio of 1.7 / 1 (cyclic carbonate / amine). The viscosity value of the obtained product was 38000 cp at 25 °C and the density was measured as 1±0.05 g / cm3 at 25 °C.

[0038] The synthesis of cyclic carbonate based monomers, synthesis of amine-terminated hydroxyurethane prepolymers, and synthesis of cyclic carbonate-terminated hydroxyurethane prepolymer, upon examination, showed that the most suitable products for the production of bio-based isocyanate-free polyurethane foam would be compositions consisting of cyclic carbonate-terminated hydroxyurethane prepolymer. The reason for this can be considered as the catalyzing effect of cyclic carbonates on sodium silicate systems. Faster foam formation is observed due to the catalyzing effect of cyclic carbonates on sodium silicate systems.

[0039] Based on these raw materials, suitable formulations were prepared by adding the necessary additives (blowing agent, catalyst, silicones) for foam formulation.

[0040] Method for the preparation of the bio-based isocyanate-free polyurethane foam of the invention comprises the process steps of:

[0041] i. Synthesizing cyclic carbonate-terminated hydroxyurethane prepolymers by reacting cyclic carbonate-based soybean with an amine compound, ii. mixing epoxy resin, trimethyl hexamethylene diamine (TMD), glass water, and blowing agent into the synthesized cyclic carbonate- terminated polyhydroxyurethane prepolymer and pouring the obtained mixture into suitable molds and surfaces.

[0042] In an embodiment of the invention, the method for the preparation of the bio-based isocyanate-free polyurethane foam of the invention comprises the process steps of:

[0043] i. synthesizing cyclic carbonate-terminated hydroxyurethane prepolymers by reacting cyclic carbonate based soybean with trimethylhexamethylene diamine (TMD) or isophorone diamine (IPDA) as amine compound in a mole equivalence ratio of 1.7:1 (cyclic carbonate:amine), ii. mixing 50-100 grams of bisphenol-A based epoxy resin, 20-40 grams of trimethyl hexamethylene diamine (TMD), 40-100 grams of glass water, and 0.5-4 grams of polymethylhydrogensiloxane based blowing agent into cyclic carbonate terminated polyhydroxyurethane prepolymer synthesized as 50-100 grams and pouring the obtained mixture into suitable molds and surfaces.

[0044] In an embodiment of the invention, the method for the preparation of the bio-based isocyanate-free polyurethane foam of the invention comprises the process steps of:

[0045] i. synthesizing cyclic carbonate-terminated hydroxyurethane prepolymers by reacting cyclic carbonate based soybean with trimethyl hexamethylene diamine (TMD) or isophorone diamine (IPDA) as amine compound in a mole equivalence ratio of 1.7:1 (cyclic carbonate:amine), ii. mixing 100 grams of bisphenol-A based epoxy resin, 40 grams of trimethyl hexamethylene diamine (TMD), 60 grams of glass water, and 2 grams of polymethylhydrogensiloxane based blowing agent into cyclic carbonate terminated polyhydroxyurethane prepolymer synthesized as 100 grams and pouring the obtained mixture into suitable molds and surfaces.

[0046] The bio-based isocyanate-free polyurethane foam of the invention comprises epoxy resin, cyclic carbonate terminated polyhydroxyurethane prepolymer, trimethyl hexamethylene diamine (TMD), glass water, and blowing agent. Said epoxy resin here is bisphenol-A based epoxy resin. In addition, said blowing agent here is polymethylhydrogensiloxane.

[0047] In an embodiment of the invention, the bio-based isocyanate-free polyurethane foam of the invention comprises 50-100 grams of epoxy resin, 50-100 grams of cyclic carbonate terminated polyhydroxyurethane prepolymer, 20-40 grams of trimethyl hexamethylene diamine (TMD), 40-100 grams of glass water, and 0.5-4 grams of blowing agent. Said epoxy resin here is bisphenol-A based epoxy resin. In addition, said blowing agent here is polymethylhydrogensiloxane.In an embodiment of the invention, the bio-based isocyanate-free polyurethane foam of the invention comprises 100 grams of epoxy resin, 100 grams of cyclic carbonate terminated polyhydroxyurethane prepolymer, 40 grams of trimethyl hexamethylene diamine (TMD), 60 grams of glass water, and 2 grams of blowing agent. Said epoxy resin here is bisphenol-A based epoxy resin. In addition, said blowing agent here is polymethylhydrogensiloxane.

[0048] After the prepared bio-based isocyanate-free polyurethane foam solution is homogeneously mixed in a container, it was poured into suitable molds and surfaces and samples were prepared for mechanical tests. For the adhesion test, the formulation mixture applied to suitable concrete surfaces was tested after 7 days. The average pull-off result of 5 samples was determined to be 2.096 N / mm2. The samples prepared for mechanical analysis were also subjected to tests after curing at room temperature for 7 days. The compression test result conducted according to ASTM D 695 standard was found to be 42.65 MPa.

[0049] Table 1. Table showing tensile strength (Mpa), compression strength (Mpa), and adhesion strength (N / mm2) values of the bio-based isocyanate-free polyurethane foam of the invention.

[0050]

[0051]

[0052] Reaction 1.

[0053] Reaction 1 shows the conversion of epoxidized soybean oil to cyclic carbonate based 5 soybean oil.

[0054]

[0055]

[0056] 5 Reaction 2.

[0057] Reaction 2 shows the synthesis scheme of the cyclic carbonate-terminated hydroxypolyurethane prepolymer.

Claims

CLAIMS1. An isocyanate-free polyurethane foam, characterized in that it comprises epoxy resin, cyclic carbonate terminated polyhydroxyurethane prepolymer, trimethyl hexamethylene diamine (TMD), glass water, and blowing agent.

2. The isocyanate-free polyurethane foam according to claim 1 , characterized in that it comprises 50-100 grams of epoxy resin, 50-100 grams of cyclic carbonate terminated polyhydroxyurethane prepolymer, 20-40 grams of trimethyl hexamethylene diamine (TMD), 40-100 grams of glass water, and 0.5-4 grams of blowing agent.

3. The isocyanate-free polyurethane foam according to claim 2, characterized in that it comprises 100 grams of epoxy resin, 100 grams of cyclic carbonate terminated polyhydroxyurethane prepolymer, 40 grams of trimethyl hexamethylene diamine (TMD), 60 grams of glass water, and 2 grams of blowing agent.

4. The isocyanate-free polyurethane foam according to any one of claims 1-3, characterized in that said epoxy resin is a bisphenol-A based epoxy resin.

5. The isocyanate-free polyurethane foam according to any one of claims 1-3, characterized in that said blowing agent is polymethylhydrogensiloxane.

6. A preparation method of the isocyanate-free polyurethane foam, characterized in that it comprises the process steps of:i. synthesizing cyclic carbonate-terminated hydroxyurethane prepolymers by reacting cyclic carbonate-based soybean with an amine compound,ii. mixing epoxy resin, trimethyl hexamethylene diamine (TMD), glass water, and blowing agent into the synthesized cyclic carbonate- terminated polyhydroxyurethane prepolymer and pouring the obtained mixture into suitable molds and surfaces.

7. The preparation method according to claim 6, characterized in that it comprises the process steps of:i. synthesizing cyclic carbonate-terminated hydroxyurethane prepolymers by reacting cyclic carbonate based soybean with trimethyl hexamethylene diamine (TMD) or isophorone diamine (IPDA) as amine compound in a mole equivalence ratio of 1.7:1 (cyclic carbonate:amine),ii. mixing 50-100 grams of bisphenol-A based epoxy resin, 20-40 grams of trimethyl hexamethylene diamine (TMD), 40-100 grams of glass water, and 0.5-4 grams of polymethylhydrogensiloxane based blowing agent into cyclic carbonate terminated polyhydroxyurethane prepolymer synthesized as 50-100 grams and pouring the obtained mixture into suitable molds and surfaces.

8. The preparation method according to claim 7, characterized in that it comprises the process steps of:i. synthesizing cyclic carbonate-terminated hydroxyurethane prepolymers by reacting cyclic carbonate based soybean with trimethyl hexamethylene diamine (TMD) or isophorone diamine (IPDA) as amine compound in a mole equivalence ratio of 1.7:1 (cyclic carbonate:amine),ii. mixing 100 grams of bisphenol-A based epoxy resin, 40 grams of trimethyl hexamethylene diamine (TMD), 60 grams of glass water, and 2 grams of polymethylhydrogensiloxane based blowing agent into cyclic carbonate terminated polyhydroxyurethane prepolymer synthesized as 100 grams and pouring the obtained mixture into suitable molds and surfaces.

9. The isocyanate-free polyurethane foam prepared by the method according to any one of claims 6-8.

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