Process for the synthesis and dispersion of polyurethane in an aqueous medium

Abstract

This invention patent pertains to the technical field of polymer dispersion processes in textile articles, comprising specific steps of polyol synthesis, prepolymer synthesis, and aqueous polymer dispersion. More specifically, it presents a first step of polyol synthesis comprising the addition of 10.0 to 40.0% vegetable oil, such as grape seed oil, 1.0 to 10.0% acidifying agent, such as formic acid, 3.0 to 15.0% oxidizing agent, such as hydrogen peroxide; 1.0 to 10.0% alkalizing agent, such as 50% sodium hydroxide, and water q.s.p. 100%; a second prepolymer synthesis step comprising the addition of 30.0 to 70.0% of the polyol obtained in the polyol synthesis step, 4.0 to 20.0% of TDI 80 / 20 isocyanate, 0.07 to 1.50% of DBTL catalyst - dibutyl tin dilaurate, and 10.0 to 45.0% of solvent, such as acetone;and a third aqueous dispersion step of the polymer comprising the addition of 20.0 to 60.0% of the prepolymer obtained in the prepolymer synthesis step, 0.1 to 5.0% of a dispersing agent, such as sodium dioctyl sulfosuccinate, 0.1 to 5.0% of an antifoaming agent, 0.5 to 10.0% of an alkalizing agent, such as triethanolamine, and water q.s.p. 100%.

Description

"PROCESS FOR THE SYNTHESIS AND DISPERSION OF POLYURETHANE IN AN AQUEOUS MEDIUM"

[001] This invention patent pertains to the technical field of polymer dispersion processes in textile articles, comprising specific steps of polyol synthesis, prepolymer synthesis and aqueous polymer dispersion.

[002] Polyurethanes (PUs) are a class of polymers that have a wide range of applications. They can be used as foams, adhesive coatings, elastomers and fibers, and when dispersed in water they can be applied in the processing of textiles in general.

[003] PUs are considered to be segmented block copolymers, formed by the reaction of diisocyanates, polyols and chain extenders. They consist of rigid and flexible segments. The reaction between diisocyanate and chain extenders forms the rigid segment, while the polyol is responsible for the flexible segment.

[004] The history of polymers shows that in 1937, Otto Bayer and colleagues in Germany, in an attempt to find a material to compete with the polyamide developed by Wallace Hume Carothers at DuPont de Nemours, Inc., created the polyurethane polymer.

[005] Industrial production of polyurethane polymer began in 1940 and experienced significant growth during the Second World War, where polyurethane foams were used in airplanes and submarines as thermal and acoustic insulation. However, commercialization only began in the 1950s, with a major boost in the production of polyurethane from Toluene Diisocyanate (TDI) in 1952.

[006] In the following years, a great development of this industry is observed. In the 1960s, the first water-soluble polymers were synthesized through the incorporation of hydrophilic ionic groups into the molecular chain, which allow for high dispersion of the polymer.

[007] From the late 1970s to the present day, there has been a strong development of polymer dispersions in aqueous media. These dispersions were developed with Petition 870260071760, dated 07 / 20 / 2026, page 12 / 31 2 / 11 all reagents directly or indirectly derived from traditional petroleum chemistry. According to what is known in the state of the art, the production of this polymer is approximately 8.5 million tons / year and among the 3 largest consumers are the footwear, coating and insulation industries.

[008] Regarding applications under textiles, according to the innovative application of Polyurethane proposed in the present invention, there are no available and current consumption data. Polyurethane dispersions in aqueous media were therefore the object of the development of the present invention.

[009] Polyurethane dispersions in aqueous media can produce different physical effects on textile products, depending on the amount applied. The advantageous physical effects obtained range from reducing pilling (loose fibers) to using textiles as a dimensional stabilizing agent, leaving textile substrates stable when washed.

[0010] Such aqueous polyurethane dispersions are applied under textile articles, although in small quantities worldwide.

[0011] The reasons for this relatively low consumption range from the limited supply of PU compounds dedicated to this purpose by industries located mainly in Europe and Asia, to their high cost when compared to other conventional acrylic-based polymers.

[0012] Another consideration regarding the use of conventional aqueous PU dispersions under textiles is associated with the high environmental impact generated during synthesis because raw materials synthesized from non-renewable resources are used.

[0013] In particular, regarding the application of polymer dispersions in textile articles, knitted or woven yarns, whether of natural or synthetic origin, may have undesirable characteristics due to certain inherent production factors. Thus, their use in textile articles requires special care, including considerations for the presence of fibrils under the articles, the level of fraying, and dimensional instability.

[0014] The high presence of fibrils under textile articles that, with use, transform into "little balls" (or pilling) that generate discomfort in their use, in addition to an appearance of Petition 870260071760, dated 07 / 20 / 2026, p. 13 / 31 3 / 11 Low-quality mesh or fabric. To eliminate this undesirable characteristic, the application of polyurethane dispersion in an aqueous medium is the most efficient solution.

[0015] Another undesirable characteristic in a textile substrate, woven on a loom, is the high level of fraying when the fabric is subjected to mechanical stresses, even of low intensity. This mechanical stress leads to fraying of the fabric, rendering it unusable. For this condition, it is also possible to minimize or even neutralize the effect with the use of PU polymer dispersions.

[0016] Problems inherent to fabrics or knits related to their dimensional instability are also mentioned. This problem can also be solved with the application of a polyurethane dispersion, and the result of this operation is a significant decrease in the shrinkage levels of fabrics and knits, bringing great benefits by avoiding material waste, as well as the consequent lower generation of waste and reduction in the consumption of textile substrates, which are stabilized by the application of polyurethane dispersions (PUDs).

[0017] Polyurethane dispersions are also used as a vehicle and crosslinking agent for microcapsules containing active ingredients such as oils, essences, moisturizing agents, and other microencapsulable active ingredients where tissue / compound bonding with a polymeric agent is required.

[0018] Furthermore, regarding the importance and motivation for using this polymer on textile substrates, we can mention the non-use of organic solvents, often flammable petroleum derivatives, in the application under textiles.

[0019] This condition provided by the present invention brings occupational safety, because the product is in an aqueous medium, therefore without risk of spontaneous combustion.

[0020] When applied under textiles, aqueous polyurethane dispersions provide extra properties of abrasion resistance, high elasticity, good thermal and chemical resistance, with low negative side impact and alterations to the substrates, such as changes in softness, feel and drape, thus preserving the good comfort conditions for the use of textiles with their application. Petition 870260071760, dated 07 / 20 / 2026, page 14 / 31 4 / 11

[0021] In relation to conventional processes for the synthesis of aqueous polymer dispersions, the acetone process is the most widely used prepolymer process. In particular, such conventional synthesis processes involve the operations of prepolymer formation, prepolymer dispersion in water, and chain extension.

[0022] Based on the good results obtained with textile articles using conventionally obtained polyurethane dispersions, this invention proposes an innovative composition and production steps for polyurethane with properties similar to those of previously produced compounds, but in an unusual way, with sustainable synthesis characteristics and steps.

[0023] According to the solution proposed by the present invention, the innovative composition and process steps involved meet the requirements of sustainability as a principle currently seen as an alternative to modern civilization, so that future generations can live safely and with quality. The subject matter of the present invention corroborates the use of techniques based on sustainability, meeting the four fundamental pillars for products and processes to be considered as positively impacting the environment: ecologically sound, economically viable, socially just, and culturally diverse.

[0024] Particularly within the first pillar (ecologically correct), the present proposal employs the application of the 3Rs tool: Reduce, Recycle, Reuse. To support and enable the productive concept, the material of the present invention results from research in Brazil on waste from its agribusiness, so that this waste can be used as an alternative to the age-old petroleum chemistry. Thus, as an objective of the present invention, alternative compositions and respective processes to traditional petroleum chemistry were developed, using products / raw materials derived from primary activities in the processing of agricultural products.

[0025] Furthermore, according to the present invention, it is the result of research into the availability of materials and their physicochemical properties that prove to be compatible with traditional raw materials for synthesis, and that also Petition 870260071760, dated 07 / 20 / 2026, page 15 / 31 5 / 11 meet the second pillar of sustainability (economically viable).

[0026] As a prerequisite for choosing alternative raw materials to those of traditional petroleum chemistry, properties such as biodegradability are observed, as cited in the publication “Latin American Journal of Energy Research (2017- V.4, N1, Pg 41-51)”, and when it comes to vegetable oils as pre-compounds for the synthesis of polyurethanes, particularly polyols, they have desirable biodegradable characteristics.

[0027] As hydroxylated vegetable oils are alternative sources of polyols, it is proposed that they be used in accordance with the present invention due to their local availability, particularly in Brazil, and that in addition to being renewable unlike petroleum and its by-products, they are sustainable, since they originate from primary activities and if not used can be just extra waste to be deposited in landfills and / or similar. DETAILED DESCRIPTION OF THE INVENTION

[0028] In the case of organic synthesis, the polyols, raw material for the synthesis of the present invention, can have their hydroxyl index normally varying between 40 and 450 degrees of hydroxylation on average, this variable being directly related to the hardness of the resulting polyurethane polymers: from light, transparent and soft, to heavy, opaque and rigid, according to the rule that the higher the degree of hydroxylation, the greater the hardness / resistance of the polymer obtained.

[0029] A preponderant part in determining the essential characteristics necessary for achieving the unusual result of the present invention lies in determining the correlation between the following attributes obtained: - degree of hydroxylation; - physical-chemical properties (such as softness and color); - resulting from the interaction with the textile without compromising its properties; - degree of cross-linking when dry and polymerized, so that it also functions as a pigment binder for printing.

[0030] Based on the balance obtained from the aforementioned needs, the degree of hydroxylation of the mixture between vegetable oils is defined as Petition 870260071760, dated 07 / 20 / 2026, p. 16 / 31 6 / 11 residues must be suitable for polyurethane synthesis, so that they meet various needs in a single formulation.

[0031] Therefore, according to the present invention, at each application concentration under textiles of the proposed polyurethane, made with the defined mixture of these oils that form the polyols, a proposed solution is obtained as per Table 1 below: Table 1 Concentration Effect obtained 5 - 20 g / L anti-pilling effect 5 - 40 g / L anti-fraying effect 5 - 100 g / L dimensional stability effect 5 - 170 g / L binder effect for pigment in printing 5 - 200 g / L microcapsule application carrier under textiles with various active ingredients

[0032] Thus, a polyurethane dispersion in an aqueous medium, produced with raw materials from sustainable sources, in a production process with low environmental impact due to its low energy and water requirements, among others, which are obtained according to the compositions and process of the present invention, has diverse and safe applications that can be successfully used in the textile industry.

[0033] According to the present invention, the process for synthesizing and dispersing polyurethane in an aqueous medium comprises: - a first step in the synthesis of the polyol comprising the addition of 10.0 to 40.0% of vegetable oil, such as grape seed oil; 1.0 to 10.0% of an acidifying agent, such as formic acid; 3.0 to 15.0% of an oxidizing agent, such as hydrogen peroxide; 1.0 to 10.0% of an alkalizing agent, such as 50% sodium hydroxide; and water QSP 100%; - a second prepolymer synthesis step comprising the addition of 30.0 to 70.0% of the polyol obtained in the polyol synthesis step; 4.0 to 20.0% of TDI 80 / 20 isocyanate; 0.07 to 1.50% of DBTL catalyst - dibutyl tin dilaurate; and 10.0 to 45.0% of solvent, such as acetone; and - a third aqueous dispersion step of the polymer comprising the addition of Petition 870260071760, dated 07 / 20 / 2026, page 17 / 31 7 / 11 20.0 to 60.0% of the prepolymer obtained in the prepolymer synthesis step, 0.1 to 5.0% of a dispersing agent, such as sodium dioctyl sulfosuccinate; 0.1 to 5.0% of an antifoaming agent; 0.5 to 10.0% of an alkalizing agent, such as triethanolamine; and water QSP 100%.

[0034] In a non-restrictive manner and according to the present invention, the first stage of polyol synthesis is carried out using various equipment, such as a glass-lined / 316 stainless steel reactor (5000 L) with agitation and jacketing, a cooling tower, a steam line, a vacuum line, an exhaust fan, a transfer pump (from the reactor to a settling tank), and a 10000 L settling tank. In particular, the reactor in which the vegetable oil oxidation reaction will occur must be resistant to an acidic environment (pH 1), and the use of a glass-lined or 316 stainless steel reactor (or superior) is indicated, and any metal part that comes into contact with the reaction medium or its vapors must be made of at least 316 steel. Furthermore, since this first stage of polyol synthesis involves an extremely exothermic reaction, and heat exchange capacity is extremely important, the use of a cooling tower and exhaust system sized accordingly is recommended.

[0035] More specifically, the first step in the synthesis of the polyol involves initially adding the vegetable oil to a reactor and activating the exhaust, and then the acidifying agent is added, and the stirring is activated.

[0036] A steam line is also activated and heating is set to 40 to 50°C. Then the steam line is switched off and a pump for the oxidizing agent is activated, with the temperature being controlled by activating a cooling tower so that it does not exceed 85°C, preferably maintaining an ideal temperature of 65 to 75°C.

[0037] In particular, the reaction is exothermic and the rate of addition controls the rate of heating of the reaction, with the addition of the oxidizing agent being carried out within 30 minutes. Specifically, the oxidizing agent is the reagent responsible for the exothermic reaction and can be used as a temperature regulator for the reaction: the faster the rate of addition, the more heat is generated. Conversely, the slower it is added, the less heat is generated. Petition 870260071760, dated 07 / 20 / 2026, page 18 / 31 8 / 11 Furthermore, adding the oxidizing agent too quickly can cause overheating of the reaction, potentially reaching temperatures above 120°C. It is recommended to add 10 to 20% of the oxidizing agent and wait for the temperature to return to 70°C before resuming additions. In case of overheating (temperature above 85°C), the addition of the oxidizing agent should be completely stopped, and the cooling tower should remain running to ensure the temperature decreases. The reactor should remain open to prevent pressurization, and additions should only resume when the reaction temperature is below 70°C.

[0038] After the addition of the oxidizing agent is complete, the reaction temperature is maintained between 65 and 75°C for 90 minutes.

[0039] Next, 100% of the water is added and the cooling tower is activated.

[0040] Also, in this first stage of polyol synthesis, the alkalizing agent is added, and the mixture is stirred for 30 minutes with cooling activated to maintain the temperature below 45°C and to prevent foam formation. In this case, the neutralization reaction is exothermic, and the rate of addition of the alkalizing agent can be used as a reaction temperature regulator. If the temperature exceeds 45°C, there is a serious risk of foam generation and overflow of the reactor contents.

[0041] Next, the contents of the reactor are transferred to the settling tank and left to stand, and after a period of rest, approximately 60% of the aqueous (lower) phase is drained into an IBC (Intermediate Bulk Container) waste reservoir.

[0042] Next, about 83% of the aqueous phase is separated at rest and 17% is emulsified. In turn, the hydrated polyol (40%) is loaded into the reactor (2 drained batches).

[0043] Finally, in a closed reactor, the steam line and the vacuum line are activated and the reactor is heated, preferably between 105°C and 110°C (not exceeding 120°C), with stirring on, and all the water is evaporated from the polyol.

[0044] Table 2 presents the products obtained, and their respective characteristics, in this first stage of polyol synthesis. Petition 870260071760, dated 07 / 20 / 2026, page 19 / 31 9 / 11 Table 2 Products Generated - 1 Batch Product Quantity Storage Location Characteristics Polyol Intermediate (reactor) 100% 10000 L Settling Tank Product composed of a mixture of polyol and wash water, neutral to alkaline in character Wet Polyol (settling tank) 40% (70% Polyol + 30% water) Can be stored in tanks or IBC reservoir Emulsified hydroxylated vegetable oil, neutral in character Residue (settling tank) 60% IBC reservoir Washing residue of the polyol rich in salts from neutralization, slightly alkaline in character (11% salts) Dry Polyol (reactor) drying of two batches of intermediate 28% Can be stored in tanks or IBC reservoir Hydroxylated vegetable oil, neutral in character

[0045] In a non-restrictive manner and according to the present invention, the second stage of prepolymer synthesis is carried out using various equipment, such as a jacketed and stirred reactor, a cooling tower, a steam line, and an exhaust system. In particular, since this second stage of prepolymer synthesis involves an exothermic reaction, the use of a jacketed reactor is recommended. In turn, the exhaust system is important to prevent the accumulation of toxic fumes.

[0046] Furthermore, some safety measures must be taken when carrying out this step, such as: since the reaction product (pre-polymer) is reactive with water and toxic, it must be stored in a suitable location; and since this reaction product is diluted in a flammable solvent, it must be stored away from ignition sources.

[0047] More specifically, the second stage of prepolymer synthesis initially involves adding the polyol to a clean reactor, turning on the stirring, steam line and vacuum line, and heating to 105°C for 30 min in order to remove any moisture from the reaction medium. Petition 870260071760, dated 07 / 20 / 2026, page 20 / 31 10 / 11

[0048] Next, the steam line is deactivated and cooled to 50°C, and the vacuum line is also deactivated, and a catalyst is added. An isocyanate is also added, maintaining the reaction temperature between 60 and 75°C, considering that the reaction is exothermic and the rate of addition controls the rate of heating of the reaction. After the isocyanate addition is complete, the reaction temperature is maintained between 60 and 70°C for 60 minutes.

[0049] Next, the cooling tower is activated and the temperature is reduced to ambient temperature.

[0050] Finally, a solvent is added and stirred for 10 minutes, during which the prepolymer can be kept in the closed reactor until completely consumed in the dispersion step, and it is still recommended to maintain slow stirring.

[0051] Table 3 presents the product obtained, and its respective characteristics, in this second stage of prepolymer synthesis. Table 3 Products Generated Product Quantity Storage Location Characteristics Pre-polymer 100% Closed reactor Product composed of an intermediate polyurethane resin containing free isocyanate

[0052] In a non-restrictive manner and in accordance with the present invention, the third stage of aqueous polymer dispersion is carried out by means of various equipment, such as a disperser with a colloidal rotor, a dispersion tank, an IBC reservoir and a transfer pump (from the reactor / container to the dispersion tank).

[0053] In particular, in this third stage of aqueous polymer dispersion, some inherent characteristics of the process are important to observe. Firstly, the dispersion process is the critical stage, and a colloidal dispersion system capable of obtaining particle sizes smaller than 20 µm in a baffled tank is indicated. Furthermore, the sizing of the colloidal dispersion system must be such that the mixing time of the product added to the medium until the Petition 870260071760, dated 07 / 20 / 2026, page 21 / 31 11 / 11 Contact with the rotor and particle formation must occur in a time not exceeding 30 seconds. Finally, the addition of the prepolymer should be done below the water level, preferably near the suction zone of the colloidal disperser.

[0054] More specifically, the third stage of aqueous polymer dispersion initially involves adding 100% water, the alkalizing agent, the dispersing agent, and the antifoaming agent to the dispersion tank.

[0055] Next, the colloidal disperser is activated, slowly adding the prepolymer over a 10-minute period, with the colloidal disperser being kept on for up to 5 minutes after the prepolymer addition is complete. Finally, the contents are transferred to the IBC reservoir.

[0056] Table 4 presents the product obtained, and its respective characteristics, in this third stage of aqueous dispersion of the polymer. Table 4. Products Generated: Product, Quantity, Storage Location, Characteristics. 100% PU Dispersion, IBC Reservoir. Product composed of an aqueous polyurethane dispersion.

Claims

1.) “PROCESS FOR THE SYNTHESIS AND DISPERSION OF POLYURETHANE IN AQUEOUS MEDIUM”, characterized by comprising: a first stage of polyol synthesis comprising the addition of 10.0 to 40.0% of vegetable oil, such as grape seed oil; 1.0 to 10.0% of an acidifying agent, such as formic acid; 3.0 to 15.0% of an oxidizing agent, such as hydrogen peroxide; 1.0 to 10.0% of an alkalizing agent, such as 50% sodium hydroxide; and water QSP 100%; a second stage of prepolymer synthesis comprising the addition of 30.0 to 70.0% of the polyol obtained in the polyol synthesis stage; 4.0 to 20.0% of TDI 80 / 20 isocyanate; from 0.07 to 1.50% of DBTL catalyst - dibutyl tin dilaurate; and from 10.0 to 45.0% of solvent, such as acetone; and a third aqueous dispersion step of the polymer comprising the addition of 20.0 to 60.0% of the prepolymer obtained in the prepolymer synthesis step, from 0.1 to 5.0% of dispersing agent, such as sodium dioctyl sulfosuccinate;0.1 to 5.0% antifoaming agent; 0.5 to 10.0% alkalizing agent, such as triethanolamine; and water QSP 100%. 2.) “PROCESS FOR THE SYNTHESIS AND DISPERSION OF POLYURETHANE IN AQUEOUS MEDIUM”, according to claim 1, characterized by: the first step in the synthesis of the polyol comprising: adding vegetable oil to a reactor and activating exhaust; adding the acidifying agent, activating agitation; activating a steam line and heating to 40 to 50°C; turning off the steam line and activating pumping of the oxidizing agent; controlling the temperature by activating a cooling tower, maintaining an ideal temperature of 65 to 75°C, so that it does not exceed 85°C; controlling the exothermic reaction, in which the addition of the oxidizing agent is carried out at 30-minute intervals; Petition 870260071760, dated 07 / 20 / 2026, p. 26 / 31 2 / 3 Maintain the reaction temperature between 65 and 75°C for 90 minutes after the oxidizing agent has finished adding; add 100% of the water; activate the cooling tower;Add the alkalizing agent and stir for up to 30 minutes with cooling activated to maintain the temperature below 45°C and to avoid foam formation; transfer the reactor contents to the settling tank and let it stand, and after the resting period; drain up to 60% of the aqueous phase - lower - into an IBC reservoir; separate 83% of the resting aqueous phase and keep 17% emulsified; load the hydrated polyol - 40% - into the reactor; activate, in a closed reactor, the steam line and the vacuum line; activate and heat the reactor, which is heated between 105°C and 110°C - not exceeding 120°C, with stirring on; and evaporate the water from the polyol; the second stage of prepolymer synthesis comprises: adding the polyol to a clean reactor, turning on the stirring, steam line and vacuum line and heating to 105°C for 30 min in order to remove any moisture from the reaction medium; Deactivate and cool the steam line to 50°C; deactivate and add a catalyst to the vacuum line;Add the isocyanate and maintain the reaction temperature between 60 and 75°C; maintain the reaction temperature between 60 and 70°C for up to 60 minutes; activate the cooling tower and reduce the temperature to room temperature; add and stir the solvent for up to 10 minutes, during which the prepolymer is kept in the closed reactor until total consumption in the dispersion step; and Petition 870260071760, dated 07 / 20 / 2026, pp. 27 / 31; 3 / 3 The third stage of aqueous polymer dispersion comprises: adding 100% of the water, the alkalizing agent, the dispersing agent, and the antifoaming agent to the dispersion tank; activating the colloidal disperser, adding the prepolymer for up to 10 minutes, with said colloidal disperser being kept on for up to 5 minutes after the prepolymer addition is complete; and transferring the contents to the IBC reservoir.