MX2011014044A - Method for the preparation of latices of thermoplastic elastomers and plastomers. - Google Patents

Abstract

A chemical method or process for obtaining an aqueous micellar system forming a stable emulsion, in which discontinuous phase interacts elastomers of the SBS type (radial or linear); as well as other types of polymers which may be of elastomeric nature or plastic nature. Said method mainly refers to the form for preparing aqueous polymeric emulsions resulting from a mixture of a polymer with a resin (hydrocarbonated, hydrogenated or styrene-acrylic), which is diluted in an azeotrope formed from aromatic components (toluene) in ethanol, this dissolution being subsequently mixed with other dissolution formed with emulsifying agents such as polyethoxylated nonylphenol ether in water with an adjusted acidity or alkalinity. The complete mixture is stirred until a homogeneous emulsion is obtained, a vacuum extraction process being used for separating a largest portion of the azeotrope for leaving a content higher than 15% in an emulsion with a liquid phase, which is mainly formed by water a nd which acts as a vehicle. The polymers proposed in the present invention refers to styrene-butadiene-styrene (SBS) copolymers of the radial and linear type, which are considered as thermoplastic elastomers, styrene butadiene copolymers of partial or gradual polystyrene (SB) block, styrene-ethylene-butylene (SEBS)ternary copolymers, ethylene-glycidyl-acrylate (EGA) copolymers and ethylene-vinyl-acetate (EVA) copolymers.

Description

METHOD FOR THE PREPARATION OF LATICES OF THERMOPLASTIC ELASTOMERS AND PLASTERS FIELD OF THE INVENTION The present invention details a chemical method or process for obtaining an aqueous micellar system that forms a stable emulsion, in whose discontinuous phase elastomers of the SBS type (radial or linear) interact; as well as other types of polymers that may be elastomeric in nature or plastic in nature, among which may be mentioned: SEBS, SB diblock copolymer with partial or gradual styrene block. EGA (Polyethylene-Glycidyl-Acrylate plastomer) and EVA (Polyethylene-Vinyl-Acetate plastomer); as well as resins of the aliphatic or vinyl acrylic hydrocarbon type depending on the application to which the formulated emulsion is intended. The formula also includes a vehicle formed by a binary azeotrope consisting of water and hydrocarbons derived from the families of the aromatic or ethyl alcohol with aromatic hydrocarbon.

BACKGROUND The processes to obtain polymer emulsions present the main challenge of having systems formed by mixtures of polymers in water that are stable and that are similar in consistency to latex, which is obtained from natural rubber. This natural rubber latex is essentially a mixture of CIS and TRANS isomers of natural emulsified polyisoprene in water that has tense-active also natural normally of protein origin.

Emulsions by definition are systems of two or more phases that without the action of a surface-active agent or surfactant are immiscible or unstable, but with the help of this form fairly stable micelle systems with a particle population of sizes in the order of 0.1 at 50 microns that in most of the time are imperceptible to the human eye, but can be identified perfectly by microscopic techniques. The stability of these systems makes them look like a single stable phase, which does not form sediments or floating particles on the surface; when this occurs, it is said that the emulsion is unstable or has been "broken", but in general the well formed emulsions have stabilities that last for a long time while maintaining the balance between the phases that comprise it.

The term latex applies to both natural and synthetic emulsions and comes from the botanical name of a "milky" fluid that is obtained from certain trees (such as Hevea Brasiliencis in Brazil, or Guayule in southeastern Mexico), where the sap is housed that allows the circulation of the nutrients of said plants. In Mexico and some countries in Latin America it is usually referred to as "serum", and it has the particularity that all the ingredients are in the form of an emulsion, which has water as the main vehicle or base.

The process for the production of rubber emulsions in water is not new, it is known that since the 1940s there are reports and patents of research aimed at protecting different technologies related to this matter. For example, in 1949, US Pat. No. 2595797 describes the production of copolymers of styrene and isobutylene using silicone oil as an antifoam additive, or US Pat. No. 2799662, which describes the preparation of aqueous emulsions of isobutylene. In these first patents a process was described that involved the following steps to obtain the aqueous polymeric emulsion: 1. Prepare a solution of the rubber in a volatile organic solvent, at a suitable concentration to be emulsified. 2. Casting said solution in water and under pressure, the water containing an emulsifying or surfactant agent such as, for example, di-octyl, sodium dodecyl-benzenesulfonate or sodium sulfo-succinate. 3. Add an antifoaming agent (such as a polysilicone oil) and stir the mixture until the emulsion is obtained. 4. Removal of the solvent by rapid evaporation or flashing (this also avoids the formation of foam). 5. Concentrate the emulsion to the expected level of solids, allowing it to stabilize for 24 hours removing any serum that could form on the surface of the emulsion (which normally contained a solids content of no more than 2% w / w).

The search for alternatives to obtain polymeric aqueous emulsions is very extensive, particularly those whose main use is focused on the preparation of modified asphalt emulsions, where asphalt is mixed with polymers to have better properties such as elastic recovery, to provide media rehabilitation and improvement of damaged pavements (as described in U.S. Patent No. 6,136,899 to Lewandowski Laurend, et al.). The scope of rehabilitation of pavements using this type of emulsions includes both pavements of asphaltic nature and hydraulic concrete.

Some other uses that have this type of polymeric aqueous emulsions are focused on the construction sector, where is the application of anti-dust or palliative to prevent dust from flying when they are building dirt roads in the opening of gaps for rural roads and that will be the basis for the rolling layers of the future pavements.

Perhaps the synthetic polymer latex most commonly used for modified asphalt emulsion applications is the SBR-based aqueous latex (styrene-butadiene elastomeric copolymer in random arrangement of the styrene-butadiene monomers in its structure). Normally, this SBR polymer comes from an emulsion polymerization synthesis, where the polymer is obtained by forming a stable aqueous emulsion from its origin, with the use of surfactants or emulsifiers of a rosin nature. One of the main limitations of this type of latex is the fact that the percentage of solids is less than 20% weight / weight (which is where the polymeric substrate is located); however, U.S. Patent No. 6,737,469B2 (Takamura, et al) proposes methods for increasing the solids content in SBR latices. On the other hand, another patent which also mentions the obtaining of SBR latices is U.S. Patent No. 4,436,850 of the Allied Corporation.

In the search for different types of aqueous polymeric latexes, there are reported patents of polymers that could compete directly on properties with natural rubber latex, such as those describing the use of polyisobutylene and derivative polymers (as described in European patent number EP). 1840153B1 and U.S. Patents 2,799,662 and 3,250,737). Other polymers also reported in aqueous emulsion are the synthetic polyisoprene latices, whose structure is more similar to the base polymer of natural rubber (US Pat. No. 3,920,601).

In addition to other polymeric species, one of the specific searches of interest was to identify copolymers derived from styrene, which would be reported in the form of an aqueous emulsion, among this search was found US Patent No. 2,274,749 which describes the formulation of styrene-styrene copolymer latexes. isobutylene, or the European patent EP 1, 840,153B1 which describes the formulation of styrene-isoprene latices type SIS synthesized by the solution polymerization process using lithium catalysts.

In the search for new technological advances with respect to the subject matter, patent application PCT / CN2000 / 000281, "FULL VULCANIZED POWDERED RUBBER WITH CONTROLLABLE PARTIOLE DIAMETER, PREPARING METHOD AND USES THEREOF", was found in the state of the art. which aims to protect a system based on vulcanized rubber powder, with a particle that goes from 20 to 200 nm, which when combined with latex and by a source of irradiation, is dispersed in it, which makes it possible for said Rubber powder tends to disperse in the plastic substrate, so it can be combined with different plastics to form thermoplastics and hardened plastics.

Likewise, the patent application EP 1085036"FORMALDEHYDE-FREE ADHESION PROMOTER COMPOSITION FOR WAISTBAND FABRIC", refers to a composition that provides adhesive characteristics between rubber latices and flexible textile substrates, which increase the strength and rigidity of the fabrics. Said composition is free of formaldehyde.

Patent application PCT / JP2005 / 013770"FLUOROPOLYMER LATEX, METHOD OF PRODUCING SAID FLUOROPOLYMER LATEX AND FLUOROPOLYMER", refers to a method for the production of a latex fluoropolymer containing a fluoropolymer and a fluorine emulsifier of the formula F (CF2) 40CF2CF20CF2COOA, where A can be a hydrogen atom, an alkali metal or NH4, said polymer is obtained by the coagulation of the latex. The latex fluoropolymer can be used as a coating for different materials, such as metal substrates, oxide-inorganic substrates, polymer substrates, synthetic fiber, glass fiber, carbon fiber or natural fiber. Said latex fluoropolymer has excellent heat resistance, oil resistance, chemical resistance, weather resistance, non-sticky, water repellent, etc.

Likewise, the patent application EP1607429"PROCESS FOR THE PREPARATION OF AQUEOUS DISPERSIONS OF PARTITIONS OF WATER-SOLUBLE POLYMERS", which comprises a method of preparing water-soluble polymer particles, combining an aqueous polymeric solution comprising a polymer soluble in water. water, in particular a polysaccharide, and an aqueous medium, and an oil base medium to form a water-soluble polymer emulsion of drops.

The patent application EP1377451"EPOXY-FUNCTIONAL POLY ERIC MICROBEADS", which aims to protect a system of epoxy polymeric microspheres and their dispersion methods thereof. The dispersion is carried out using a non-aqueous cationic photopolymerization suspension-dispersion. The polymeric microspheres are modified with a variety of additional groups that react with agents with epoxy functional groups.

The patent application with publication number WO2002059172, "PROCESS FOR PRODUCING FINE CURED-RESIN PARTIOLE", aims to protect a process for the production of cured, spherical and fine resin particles, having a diameter of 10 g or less. Said process comprises curing a dispersion of a thermosetting resin obtained also by dispersing a thermosettable polymerizable resin in its aqueous phase, at ordinary temperature or with a heater in the presence of a hardener and optionally an accelerator; Subsequently, remove the water and then dry the resulting particles optionally after washing. By careful selection of the raw materials to be used, the fine particles of cured resin can be regulated in their refractive index, oil absorption, and other properties regulated in wide margins. The degree of hydrophilicity or lipophilicity of the particles can also be regulated. They can be used in various applications, for example, as a crack inhibitor or breakage reducing agent or as a modifier such as, for example, an agent for the reduction of residual monomers contained in a polymer.

Finally, the patent application ES2170257, "METHOD FOR MANUFACTURING SOLIDIFIED RESIN PARTICLES", aims to protect a suspension of aminoplast or hardened phenoplast resin finally divided, in particular of an aqueous melamine resin or its precursors with an insoluble stabilizing agent. in water, in particular a microcrystalline cellulose; enough water is added to exceed the water tolerance level of the resin and thus form a uniform emulsion or suspension of resin particles in water. The curing of the resin is then advanced, by heating for example, to form partially or fully cured resin particles with a relatively uniform particle size.

From the above it follows that large amounts of energy are required for the preparation of polymeric emulsions, in addition to the fact that the systems described above do not guarantee a stability in the components of the emulsion.

Problem to solve: In the state of the art, have been infinity of processes and methods to make suspensions, some with complex systems or methods to make polymeric emulsions, however, the stability of the systems of emulsions found, is not enough to guarantee that the Emulsion does not break with the passage of time, since the balance between the phases does not remain constant. Likewise, some processes require high amounts of energy to make the emulsion, which greatly increases production costs.

In the state of the art, they have found many processes and methods to make suspensions, some with complex systems or methods to make polymeric emulsions, however, although there are millions of detailed processes, no process was found that details the use of azeotropic systems as means of dissolution and that said azeotrope function as a vehicle during the process of latex formation, meaning by azeotrope a mixture of solvents including water, binary or ternary that in a certain composition has properties as if it were a single component (for example in its boiling temperature), and on the other hand, the use of a resin that allows to have a stable system of the polymer mixture with resin in aqueous medium by means of the use of surfactants that allow to maintain the polymer-resin system at the size of particles that form micelles between 2 to 20 microns. .

The processes found in the state of the art, use solvent as means of dissolution of the polymer and present the following disadvantages: o They use high pressure systems or reactors (more than 2 kilos force) when this solution is combined with the aqueous system that includes the surfactants. This is required because the water must necessarily be hot at a higher temperature than the solvent used to achieve the dissolution of the polymer, which means that in the system (which is a closed system), the internal pressure was increased by the sudden flashing of the solvent.

When this abrupt exchange of a medium with agitation is carried out, an excessive formation of foam occurs which is often difficult to control. One of the most used forms of control is low or no agitation (less than 40 revolutions per minute) and a slow flow control of the solution with the aqueous medium. The previous thing causes that this process is slow to separate completely the solvent phase and to avoid at the same time the formation of foam (more than 24 hours), o This foaming process requires the removal of excess foam formation, which when stabilized generates a serum that contains in its composition a polymer content of up to 2% weight / weight that is not used (often an expression that is used to refer to this serum is as residual grout).

Solution: It is an object of the present invention to provide an aqueous polymer emulsion based on or from the production of a polymer mixture with a resin, and which is diluted with a formulated azeotrope.

It is another object of the present invention to provide an aqueous polymer emulsion containing a balance between its phases.

It is another object of the present invention to provide an aqueous polymeric emulsion that does not require high energy consumption for its processing.

It is another object of the present invention to provide an aqueous polymeric emulsion whose formation process is less than 10 hours to completely remove the solvent phase.

It is another object of the present invention to provide an aqueous polymeric emulsion whose formation process prevents foaming and polymer losses.

It is another object of the present invention to propose the use of a hydrocarbon, hydrogenated or styrene-acrylic resin for the polymer emulsion. It is another object of the present invention to propose the use as azeotrope of a water-toluene or ethanol-toluene mixture for the polymer emulsion.

It is also an object of the present invention to propose a method specifically designed for the production of the aqueous polymeric emulsion, which provides the option of varying the mixture according to the desired application.

BRIEF DESCRIPTION OF THE INVENTION: The subject proposed by this patent and which differs from all previous art found is the description of the form for preparing aqueous polymeric emulsions from the preparation of a polymer mixture with a resin (which may be hydrocarbon, hydrogenated or styrene-acrylic) that is diluted in an azeotrope formulated, for example, from aromatic components (such as toluene) in ethanol, once this solution is made, it is mixed with another solution that is formed with emulsifying agents of the ether type of Nonylphenolic polyethoxylated in water with acidity or adjusted alkalinity. The complete mixture is stirred until a homogeneous emulsion is obtained and a greater part of the azeotrope is separated by means of a vacuum extraction process to leave a content greater than 15% of the polymer in an emulsion with a liquid phase which is mostly water and which it acts as a vehicle.

The polymers proposed in this invention are styrene-butadiene-styrene (SBS) copolymers of the radial and linear type considered thermoplastic elastomers, styrene-butadiene block copolymers of partial or gradual polystyrene (SB), ternary copolymers of styrene-ethylene- butylene (SEBS), ethylene glycidyl acrylate (EGA) copolymers and ethylene vinyl acetate (EVA) copolymers.

An azeotrope is a combination of liquid materials (usually between two to three ingredients) that behave in a certain proportion as if it were a single type of compound with unique or equivalent properties for all the components that make it up, such as the temperature of boiling, once the balance of proportions of the ingredients that make up the azeotrope is broken, each ingredient returns to its original properties. The azeotrope of this invention is used as a means that helps to compatibilize the polymer with water in synergy with the resin and allows to generate emulsions of the organic-aqueous phase type, also said azeotrope can be miscible with other solvents of an aromatic and aliphatic nature, also allowing generate emulsions, polymeric type organic phase-organic phase.

The use of emulsifying agents of the polyethoxylated nonylphenol ether type in water or in a solvent medium, allows to work with different levels of acidity or alkalinity, including the neutral state. This is important because it allows to define the character of the emulsion with respect to its cationic, anionic and non-ionic nature, which defines the type of application to which the formulated emulsion is directed.

With respect to the diversity of applications that the polymeric emulsions proposed in the use of this inventive material may have, it is considered that in particular emulsions of cationic nature can be used to formulate modified asphalts that have application in pavements and where the properties are improved of elastic and rheological recovery in the modified asphalt when compared to the virgin asphalt from which it is split.

Perhaps the greatest application of these polymeric emulsions (either cationic or anionic) occurs in the preparation of modified asphalt emulsions, where the polymeric latex, in any of its electric charge character, is mixed with the asphalt by the use of a colloidal mill and where from the nature of the latex and type of emulsifier and the proper pH control of the final emulsion can also have modified cationic, anionic and nonionic emulsions for applications of seal waterings, leagues and surface treatments of pavements that require rehabilitation.

In the waterproofing sector of asphaltic nature, this type of polymeric emulsions proposed can be added in reduced asphalts. { cut backs) with solvents such as naphthas, fuel oils and diesel which are known as asphalt adhesives, for the sealing of cracks in ceilings.

The non-ionic or neutral polymeric latices allow to formulate paints with a seal-like rubberized finish, which covers the porosities particularly in the treatment of hydraulic concrete walls, although paints can also be formulated for garrisons and transit lines on roads; as well as paintings for domestic use.

DESCRIPTION OF THE FIGURES Figure 1 schematically represents the steps of preparing polymeric latex emulsion from an azeotrope: 1. Preparation of a toluene / water or toluene / ethanol mixture. 2. Addition of the polymers in a system with turbulent agitation that maintains a Reynolds number of 10,000 SBS, SEBS, SB, EGA and / or EVA type elastomers. 3. Maintain agitation for three to five hours without heating (room temperature). 4. Add vinyl acrylic or hydrocarbon aliphatic resin and maintain agitation. 5. Add zinc oxide in a proportion of 1 to 3% w / w in the formulation. 6. Separately in another tank with gentle agitation (300 to 600 revolutions per minute), a solution containing 2.5 to 4% w / w of polyethoxylated nonylphenol ether surfactant (hydroxyl number of 80 to 85) is prepared and water, which will be added to the latex preparation system described to point (5) above, in a proportion of 25 to 50% w / w in the formulation. 7. The above aqueous solution is added to the mixture under stirring and from this moment the mixture becomes exothermic with elevation of the temperature, which must be maintained by cooling of the agitation system at maximum 45 ° C. Agitation will continue for another hour. 8. The mixture is transferred to a vacuum pressure system provided with heating, where the temperature between 70 and 90 ° C is controlled. 9. The latex polymer is obtained.

Figure 2 schematically represents the formation of mycelia, where the surfactant surrounds the SBS / Resin mixture.

DETAILED DESCRIPTION OF THE INVENTION The present invention describes a way to prepare aqueous polymeric emulsions from the preparation of a polymer mixture with a resin (which may be hydrocarbon, hydrogenated or styrene-acrylic type) that is diluted in a formulated azeotrope, for example, from aromatic components (such as toluene) in ethanol, once this solution is made, it is mixed with another solution that is formed with emulsifying agents of the nonylphenolic ether type polyethoxylated in water with acidity or adjusted alkalinity.

The polymers to be used in the present invention are styrene-butadiene-styrene (SBS) copolymers of the radial and linear type considered thermoplastic elastomers, styrene-butadiene copolymers of partial or gradual polystyrene block (SB), ternary copolymers of styrene-ethylene- butylene (SEBS), ethylene glycidyl acrylate (EGA) copolymers and ethylene vinyl acetate (EVA) copolymers.

Likewise, the possibility of using two types of azeotropic systems is described, on the one hand the azeotrope formed by the Ethanol / Toluene system (with azeotropic boiling temperature of 76.7 ° C) is used; On the other hand, another azeotropic system formed by the Toluene / water mixture (which has an azeotropic boiling temperature of 84 ° C) is also proposed.

There is also the possibility of selecting the type of resin to be used which, in the case of the examples mentioned in this invention, proposes two types: on the one hand, an aliphatic hydrocarbon resin; and on the other hand, a resin of the vinyl acrylic type. The selection of the resin and elastomer are chosen according to the application that can be given to the type of polymeric emulsion formulated and that will be detailed later. In the same way, you can use another type of resins that can be hydrogenated, acrylic and styrene-acrylic.

With the azeotrope formed by the Ethanol / Toluene system which is richer in ethanol than in toluene, latices or polymeric emulsions can be formulated with elastomeric copolymers of the SBS type (styrene-Butadiene-Styrene thermoplastic elastomer in its radial and linear forms), SEBS (styrene-ethylene-butylene-styrene thermoplastic elastomer); also with diblock-type thermofix copolymer SB (styrene-butadiene copolymer of gradual or partial styrene block); EGA plastomer type copolymer (Polystyrene-Giicidyl-Acrylate plastic) or EVA type (Polyethylene-V'myl-Acetate) from the steps mentioned below in examples (1) and (2). These two examples, described below, mention the use of an aliphatic hydrocarbon type resin. On the other hand, using the same type of azeotropic system, example (3) is mentioned combining the different types of elastomers and plastomers mentioned in the previous paragraph but with the alternative use of vinyl acrylic resin.

EXAMPLES Example 1). Where a polymeric emulsion of elastomers of type SB, SBS or SEBS can be formulated in combination with an aliphatic hydrocarbon resin: 1. Make a Toluene / Ethanol mixture using the molar ratio 0.1905 mol% of toluene molar fraction (molecular weight = 92 g / mol, boiling temperature = 110.6 ° C) with 0.8095 mol% molar fraction of Ethanol (molecular weight = 46 g / mol, boiling temperature = 78.5 ° C). This azeotropic solution will constitute 41% w / w of the total formulation and has a boiling point as azeotrope of 76.7 ° C. 2. In a system with turbulent agitation that maintains a Reynolds number of 10,000, between 5 and 15% weight / weight of type SB, SBS or SEBS elastomer is added. 3. Maintain agitation for three to five hours without heating (room temperature). 4. Without stopping the stirring add aliphatic hydrocarbon resin with melting point of 100 ° C and molecular weight around 1100 Daltons (GPC), in a proportion between 5 and 15% w / w in the formulation. 5. Maintain agitation for three more hours at the same conditions. 6. Zinc oxide is added in a proportion between 0.5 and 3% w / w in the formulation and the stirring conditions described above are maintained for an additional hour. 7. Separately in another tank with gentle agitation (300 to 600 revolutions per minute), a solution containing 2.5 to 4% w / w of polyethoxylated nonylphenol ether surfactant (hydroxyl number of 80 to 85) is prepared and water, which will be added to the latex preparation system described to point (6) above, in a proportion of 25 to 50% w / w in the formulation. 8. The aqueous surfactant solution described above is added to the polymer mixture under agitation and from that moment said mixture becomes exothermic with rise in temperature, which must be maintained by cooling the agitation system to a maximum of 45 ° C. Agitation will continue for another hour. 9. The mixture is transferred to a vacuum pressure system provided with heating, where the temperature is controlled at 76.7 ° C, recovering azeotropic mixture up to a maximum 90% weight / weight ratio with respect to the initial weight used in the formulation. With this formulation, a latex can be obtained even with polymer contents between 7 and 24% w / w of total polymer.

Example (2) Where a polymeric emulsion of EGA or EVA type plastomers can be formulated in combination with an aliphatic hydrocarbon resin: 1. Make a Toluene / Ethanol mixture using the molar ratio 0.1905 mol% of toluene molar fraction (molecular weight = 92 g / mol, boiling temperature = 110.6 ° C) with 0.8095 mol% molar fraction of Ethanol (molecular weight = 46 g / mol, boiling temperature = 78.5 ° C). This azeotropic solution will constitute 41% w / w of the total formulation and has a boiling point of 76.7 ° C.

In a turbulent agitation system that maintains a Reynolds number of 10,000, 9 to 20% weight / weight of EGA or EVA copolymer is added.

Maintain agitation for three to five hours without heating (room temperature).

Without stopping the stirring add aliphatic hydrocarbon resin with melting point of 100 ° C and molecular weight around 1 00 Daltons (GPC), in a proportion of 5 and 15% w / w in the formulation.

Maintain agitation for three more hours at the same conditions.

Zinc oxide is added in a proportion of 0.5 to 3% w / w in the formulation.

Separately in another tank with gentle agitation (300 to 600 revolutions per minute), a solution containing 2.5 to 4% w / w of polyethoxylated nonylphenol ether surfactant (hydroxyl number of 80 to 85) and water is prepared , which will be added to the latex preparation system in a proportion of 21 to 45% weight / weight in the formulation. 8. The above aqueous solution is added to the stirring mixture and from that moment the mixture becomes exothermic with elevation of the temperature, which must be maintained by cooling the stirring system to a maximum of 45 ° C. Agitation will continue for another hour. 9. The mixture is transferred to a vacuum pressure system provided with heating, where the temperature is controlled at 76.7 ° C, recovering azeotropic mixture up to a maximum 90% weight / weight ratio with respect to the initial weight used in the formulation. With this formulation, a latex with 15 to 32% w / w of total polymer can be obtained.

Example (3) Where a polymeric emulsion of elastomers of the type SB, SBS or SEBS can be formulated in combination with an acrylic resin. 1. Make a Toluene / Ethanol mixture using the molar ratio 0.1905 mol% of toluene molar fraction (molecular weight = 92 g / mol, boiling temperature = 1 10.6 ° C) with 0.8095 mol% molar fraction of Ethanol (molecular weight = 46 g / mol, boiling temperature = 78.5X). This azeotropic solution will constitute 41% w / w of the total formulation and has a boiling point of 76.7 ° C. 2. In a system with turbulent agitation that maintains a Reynolds number of 10,000, between 10 and 20% weight / weight of type SB, SBS or SEBS elastomer is added.

Maintain agitation for three to five hours without heating (room temperature).

Without stopping the stirring add vinyl acrylic resin (50% solids content, viscosity from 1700 to 1800 cP, pH from 4 to 4.5) in a proportion between 15 and 25% w / w of dry base resin.

Maintain agitation for three more hours at the same conditions.

Calcium oxide is added in a proportion between 5 and 9% w / w in the formulation.

Separately in another tank with gentle agitation (300 to 600 revolutions per minute), a solution containing 2 to 4% w / w of polyethoxylated nonylphenol ether surfactant (hydroxyl number of 80 to 85) is prepared and water, which will be added to the latex preparation system in a proportion of 20 to 35% w / w in the formulation.

The above aqueous solution is added to the stirring mixture and from that moment said mixture becomes exothermic with elevation of the temperature, which must be maintained by cooling the stirring system to a maximum of 45 ° C. Agitation will continue for another hour.

The mixture is transferred to a vacuum pressure system provided with heating, where the temperature is controlled to 76.7X, recovering azeotropic mixture up to a maximum 90% weight / weight ratio regarding the initial weight used in the formulation. With this formulation a latex with 15 to 25% w / w of total polymer can be obtained.

The diagram (1) summarizes the steps to be followed in the preparation of the polymer emulsion latexes described in examples (1), (2) and (3), starting from toluene / ethanol.

Diagram 1.- Preparation of polymeric latex emulsion from toluene azeotrope / ethanol PREPARATION OF AZEOTROPO TOLUENO / ETANOL ADDITION OF POLYMERS SB, SBS, SEBS, EGA or EVA MAINTAIN AGITATION OF THE POLYMER WITH THE AZEOTROPE, IN A SISTEMAQUEPERMITA TURBULENTA AGITATION (No.

REYNOLS = 10000), P0R3A 5 HOURS ADDITION OF 1CHIDROCARBONED RESIN VINILACRAL CLIFF KEEP AGITATION FOR THREE ADDITIONAL HOURS ADDITION OF ZINC OXIDE OR CALCULATION AND DISSOLUTION OF TENSITIVE PREPARATION OF SOLUTION OF OXID ADDITION OF MAINTAINING TESNSOACTIVE CONTROL TYPE ETER OF ZINC 0 CALCIUM TEMPERATURE AT 45'C AND CONDITIONS NONIL-PHENOL-POLYETOXYLATE (No.

OF AGITATION BY UNAHORAMAS DEHIDROXILODE80A 85) YAGUA PREVIOUS MIXING TRANSFER EVEN AVAILABLE PRESSURE SYSTEM RECOVER MIXING 1 AZEOTROPIC FOR DISTILLATION TO VACUUM? 76.7? OBTAINING LATEX FROM POLIMERO There is another process where another azeotrope is used but now made up of the Tolueno / Agua system, where toluene is 86.5% and water is 13.5% weight / weight. This system, which has a boiling point of 84 ° C, also makes it possible to formulate latexes with elastomeric copolymers of type SB, SBS and SEBS, as well as plastomer-type copolymers such as EGA or EVA. As examples (1), (2) and (3) described above, it is possible to combine with this system hydrocarbon-type resins, as well as vinyl acrylic resins, as described in examples (4), (5) and (6) following.

Example (4) Where a polymeric emulsion of elastomers of type SB, SBS or SEBS can be formulated in combination with an aliphatic hydrocarbon resin: a) Make a Toluene / water mixture using the weight / weight percentage ratio of 86.5% Toluene (molecular weight = 92 g / mol, boiling temperature = 1 0.6 ° C) with 13.5 mol% of water (molecular weight = 18 g / mol, boiling temperature = 100 ° C). This azeotropic solution will constitute 9 to 16% w / w of the total formulation and has a boiling point of 84 ° C. b) In a system with turbulent agitation that maintains a Reynolds number of 10000, 25 to 35% weight / weight of elastomer type is added.

SB, SBSó SEBS. c) Keep stirring for three hours without heating (room temperature). d) Without stopping the stirring add aliphatic hydrocarbon resin with melting point of 100 ° C and molecular weight around 1100 Daltons (GPC), in a proportion of 15 to 19% weight / weight in the formulation. e) Keep the agitation for three more hours at the same conditions. f) Zinc oxide is added in a proportion of 1 to 3% w / w in the formulation. g) Separately in another tank with gentle agitation (300 to 600 revolutions per minute), a solution containing 2.5 to 4.5% w / w of polyethoxylated nonylphenol ether surfactant (hydroxyl number of 80 to 85) is prepared and water, which will be added to the latex preparation system in a proportion between 20 to 30% w / w in the formulation. h) The above aqueous solution is added to the mixture under stirring and from that moment the mixture becomes exothermic with elevation of the temperature, which must be maintained by cooling the agitation system to a maximum of 45 ° C. Agitation will continue for another hour. i) Transfer the mixture to a vacuum pressure system provided with heating, where the temperature is controlled at 84 ° C, recovering azeotropic mixture in a proportion of 90% weight / weight with respect to the initial weight used in the formulation. With this formulation, a latex with 35 to 45% w / w of total polymer can be obtained.

Example (5). Where EGA or EVA plastomers can be used in combination with an aliphatic hydrocarbon resin: 1. Make a Toluene / water mixture using the weight / weight percentage ratio of 86.5% Toluene (molecular weight = 92 g / mol, boiling temperature = 110.6X) with 13.5 mol% of water (molecular weight = 18 g / mol, temperature boiling = 100 ° C). This azeotropic solution will constitute 5 to 15% w / w of the total formulation and has a boiling point of 84 ° C. 2. In a turbulent agitation system that maintains a Reynolds number of 2000, 20 to 30% w / w of EGA or EVA type copolyme is added. 3. Maintain the agitation for three hours without heating (room temperature). 4. Without stopping the stirring add aliphatic hydrocarbon resin with melting point of 100 ° C and molecular weight around 1 100 Daltons (GPC), in a proportion of 13 to 17% w / w in the formulation. 5. Maintain agitation for three more hours at the same conditions. 6. Zinc oxide is added in a proportion of 0.5 to 2% w / w in the formulation. 7. Separately in another tank with gentle agitation (300 to 600 revolutions per minute), a solution containing 2.5 to 4.5% w / w of polyethoxylated nonylphenol ether surfactant (hydroxyl number of 80 to 85) and water is prepared , which will be added to the latex preparation system in a proportion of 15 to 23% w / w in the formulation. 8. The above aqueous solution is added to the stirring mixture and from that moment the mixture becomes exothermic with elevation of the temperature, which must be maintained by cooling the stirring system to a maximum of 45 ° C. Agitation will continue for another hour. 9. The mixture is transferred to a vacuum pressure system provided with heating, where the temperature is controlled at 84 ° C, recovering azeotropic mixture in a proportion of 40% weight / weight with respect to the total weight of the formulation. With this formulation, a latex with 27 to 38% w / w of total polymer can be obtained.

Example (6). Where you can formulate a polymeric emulsion of elastomers of type SB, SBS or SEBS in combination with an acrylic resin: Make a Toluene / water mixture using the weight / weight percentage ratio of 86.5% Toluene (molecular weight = 92 g / mol, boiling temperature = 110.6X) with 13.5 mol% of water (molecular weight = 18 g / mol, temperature boiling = 100 ° C). This azeotropic solution will constitute 9 to 16% w / w of the total formulation and has a boiling point of 84 ° C.

In a turbulent agitation system that maintains a Reynolds number of 10000, 25 to 35% weight / weight of type SB, SBS or SEBS elastomer is added.

Maintain the agitation for three hours without heating (room temperature).

Without stopping the stirring, add vinyl acrylic resin (50% solids content, viscosity from 1700 to 1800 cP, pH from 4 to 4.5) in a proportion between 5 and 25% w / w of dry base resin.

Maintain agitation for three more hours at the same conditions.

Zinc oxide is added in a proportion of 1 to 3% w / w in the formulation.

Separately in another tank with gentle agitation (300 to 600 revolutions per minute), a solution containing 2.5 to 4.5% w / w of polyethoxylated nonylphenol ether surfactant (hydroxyl number of 80 to 85) and water is prepared , which will be added to the latex preparation system in a proportion between 18 to 28% weight / weight in the formulation. 8. The above aqueous solution is added to the stirring mixture and from that moment the mixture becomes exothermic with elevation of the temperature, which must be maintained by cooling the stirring system to a maximum of 45 ° C. Agitation will continue for another hour. 9. The mixture is transferred to a vacuum pressure system provided with heating, where the temperature is controlled at 84 ° C, recovering azeotropic mixture in a proportion of 90% w / w from the initial weight used in the formulation. With this formulation, a latex with 35 to 45% w / w of total polymer can be obtained.

The diagram (2), summarizes the steps for the preparation of polymeric latex emulsion from a toluene / water azeotrope, of the examples (4), (5) and (6), Diagram 2.- Preparation of polymeric latex emulsion from azeotrope of toluene / water.

In relation to the comparative properties of the different types of polymeric latices that can be obtained, the following table 1 summarizes these properties compared to a commercial SBR latex commercialized on the market.

Table 1.- Com- tative properties between different types of latex.

Set at temperature, time and agitation. b. ASTMD1439.

Applications The main applications of the present invention, with their physical-chemical properties described, are detailed below: Application 1. Modified asphalt emulsion (PME).

Since the asphalt is par excellence the bonding or adhesive medium of the stone aggregates of a pavement. Over time and due to friction factors of the tires, as well as climatic variables (changes in seasonal temperature, rain, wind, etc.); the asphalt loses cohesive force and degrades, causing faults such as cracks and ruts between the main ones.

Modified asphalt emulsions have a predominant role in the rehabilitation treatment of worn asphalt pavements, although there are also practices on hydraulic concrete pavements. One of the treatments of greater application is what is known as gravel seal irrigation or "Chip sea /", where the cationic emulsions of fast breakage of asphaltic nature have great application. In these emulsions, the polymers impart resistance and durability to the asphalt seal that remains on the pavement once the emulsion has been laid and when the gravel material is laid over the seal, it is adhered to this seal. Table 2 presents the results of characterization of modified asphalt emulsions that are compared against a conventional unmodified asphalt emulsion.

For the preparation of this modified emulsion of asphalt is used a device known as a colloidal mill that mixes the virgin asphalt in a liquid state (around 145 ° C) with a solution of soap or surfactant that carries within its composition any of the polymeric latices which have been described in this invention particularly those where the hydrocarbon resin of the examples (1), (2), (4) and (5) are used.

The results obtained in table 2 show that the polymer latices allow to improve the properties of the asphalt when they are combined in a modified emulsion of asphalt, particularly highlight the elastic recovery variables in the emulsion residue both at a temperature of 25 ° C with a low temperature, while the conventional asphalt residue does not show elastic recovery.

On the other hand, Table 3 presents the measurement of the particle size of the particles that form the micelles in each modified emulsion of prepared asphalt, determined through fluorescence microscopy.

Table 2.- Properties of modified asphalt emulsions.

Table 3.- Measurement of particle size in modified asphalt emulsions.

Application 2.- Coatings for sidewalk trim and paint traffic From a polymeric formulation of elastomers of type SB, SBS or SEBS in combination with an acrylic resin, can be combined in a proportion from 14 to 20% weight / weight, of loads of kaolin, calcium carbonate or silica type, a pigment like titanium or ferric oxide depending on the color you want give the coating (white or red, for example) and in a ratio between 12 and 18% weight / weight, phenolic antioxidant between 1 and 3% weight / weight and the rest Complete 100% of the formulation with any of the emulsions of the examples mentioned below.

From said formulation, resistance to aging was compared simulating accelerated weather conditions using a computer weatherometer ASTRA with the following conditions: a) Pressure 0.1 Pa b) Temperature cycles: i. Day simulation: 50 ° C with humidity of 70% on the mass of air, 12 hours ii. Night simulation: 25 ° C with humidity of 50% on the mass of air, 12 hours c) forced convection airflow of 40 ml / minute d) Simulation of water spray by spray at 0.4 ml / minute in 15-minute cycles every 168 hours. e) Regulation of Xenon source at 1750 lumens. f) Voltage: 400 milliAmperes g) Total power factor: 0.76 h) Test surface: Test sheets 1 inch x 3 inches and 2 mm thick. Stainless steel material i) Average thickness of applied film: 2 millimeters (microtome) once the surface is dry to 4 bar pitch.

Table 4 presents the performance of the coating formulated against commercial products found in the Mexican market.

Table 4.- Results of failure due to cracking in the films placed in the plates of laboratory sheet.

Claims (12)

1. Method to prepare latices of aqueous polymeric emulsions, characterized by the use of a mixture of azeotropes formed by a system of Toluene / Ethanol and Toleno / Water, which allows to generate a means to disperse the polymer, reduce its particle size and mix with a aliphatic hydrocarbon resin or acrylic vinyl that will serve as a compatibilizing agent between the polymer and the surfactant additive that is in aqueous solution.

2. Method for preparing latices of aqueous polymeric emulsions, from a Toluene / Ethanol mixture according to claim 1, characterized in that it consists of the following steps to carry out the emulsion: a) Make a Toluene / Ethanol mixture using the molar ratio 0.1905 mol% of toluene molar fraction (molecular weight = 92 g / mol, boiling temperature = 110.6 ° C) with 0.8095 mol% of ethanol molar fraction (molecular weight = 46 g / mol, boiling temperature = 78.5X). This azeotropic solution will constitute 41% w / w of the total formulation and has a boiling point as azeotrope of 76.7 ° C. b) In a system with turbulent agitation that maintains a Reynolds number of 10,000, between 5 and 20% weight / weight of type SB, SBS or SEBS elastomer or EGA or EVA copolymer is added. c) Keep stirring for three to five hours without heating (room temperature). d) Without stopping the stirring add aliphatic hydrocarbon resin with melting point of 100 ° C and molecular weight around 1100 Daltons (GPC), in a proportion between 5 and 15% w / w in the formulation, or vinyl acrylic resin (content of solids of 50%, viscosity of 1700 to 800 cP, pH of 4 to 4.5) in a proportion between 15 and 25% w / w of dry base resin. e) Keep the agitation for three more hours at the same conditions. f) Zinc oxide or calcium oxide is added in a proportion between 0.5 and 9% w / w in the formulation and the agitation conditions described above are maintained for one more hour. g) Separately in another tank with gentle agitation (300 to 600 revolutions per minute), a solution containing 2.5 to 4% w / w of polyethoxylated nonylphenol ether surfactant (hydroxyl number from 80 to 85) is prepared ) and water, which will be added to the latex preparation system described up to point (6) above, in a proportion of 20 to 50% w / w in the formulation. h) The aqueous surfactant solution described above is added to the stirring polymer mixture and from that moment said mixture becomes exothermic with elevation of the temperature, which must be maintained by cooling the agitation system to a maximum of 45 ° C. Agitation will continue for another hour. i) The mixture is transferred to a vacuum pressure system provided with heating, where the temperature is controlled at 76.7 ° C, recovering azeotropic mixture up to a maximum 90% weight / weight ratio with respect to the initial weight used in the formulation. With this formulation, a latex can be obtained even with polymer contents between 6 and 35% w / w of total polymer.

3. Method for preparing latices of aqueous polymeric emulsions, from a Toluene / Water mixture according to claim 1, characterized in that it consists of the following steps to carry out the emulsion: a) Make a Toluene / water mixture using the weight / weight percentage ratio of 86.5% Toluene (molecular weight = 92 g / mol, boiling temperature = 110.6 ° C) with 13.5 mol% of water (molecular weight = 18 g / mol, boiling temperature = 100 ° C). This azeotropic solution will constitute 5 to 16% w / w of the total formulation and has a boiling point of 84 ° C. b) In a system with turbulent agitation that maintains a Reynolds number of 10000, 25 to 35% weight / weight of SB type elastomer, SBS or SEBS, is added. c) Keep stirring for three hours without heating (room temperature). d) Without stopping the stirring add aliphatic hydrocarbon resin with a melting point of 100 ° C and molecular weight around 1100 Daltons (GPC), in a proportion of 15 to 19% w / w in the formulation or vinyl acrylic resin (content of solids of 50%, viscosity of 1700 to 1800 cP, pH of 4 to 4.5) in a proportion between 15 and 25% w / w of dry base resin. e) Keep the agitation for three more hours at the same conditions. f) Zinc oxide is added in a proportion of 0.5 to 3% w / w in the formulation. g) Separately in another tank with gentle agitation (300 to 600 revolutions per minute), a solution containing 2.5 to 4.5% w / w of polyethoxylated nonylphenol ether-type surfactant (hydroxyl number of 80 to 85) is prepared and water, which will be added to the latex preparation system in a proportion between 15 to 30% w / w in the formulation. h) The above aqueous solution is added to the mixture under stirring and from that moment the mixture becomes exothermic with elevation of the temperature, which must be maintained by cooling the agitation system to a maximum of 45 ° C. Agitation will continue for another hour. i) Transfer the mixture to a vacuum pressure system provided with heating, where the temperature is controlled at 84 ° C, recovering azeotropic mixture in a proportion of 90% weight / weight with respect to the initial weight used in the formulation. With this formulation, a latex with 27 to 45% w / w of total polymer can be obtained.

4. Method for preparing latices of aqueous polymeric emulsions, characterized in that it gives the possibility of using resins of different nature as hydrogenated, styrenic and styren-acrylic.

5. Method for preparing latexes of aqueous polymeric emulsions, characterized in that the use of the aliphatic hydrocarbon resin with a melting point of 100 ° C and a molecular weight of around 1100 Daltons (GPC) as a compatibilizing agent of the polymer molecules to be emulsified and the surface active agent that is in aqueous solution, forms the micelle of the polymer system in water, since the resin swells less in the solvent medium of the azeotrope and helps to improve the interaction of the surfactant with the polymeric base to have greater affinity for polarity, since the polymer chains with the resin at the end the polymer phase is surrounded by the surfactant.

6. Method for preparing latices of aqueous polymeric emulsions, characterized in that the use of the vinyl acrylic resin used (50% solids content, viscosity of 1700 to 1800 cP, pH of 4 to 4.5) as a compatibilizing agent of the polymer molecules it wishes to emulsify and the surfactant that is in aqueous solution, forms the micelle of the polymeric system in water, since the resin swells less in the solvent medium of the azeotrope and helps to improve the interaction of the surfactant with the polymeric base to have greater Affinity by polarity, since the polymer chains with the resin at the end of the polymer phase is surrounded by the surfactant.

7. Method for preparing latices of aqueous polymeric emulsions, characterized in that the type emulsions prepared from hydrocarbon resins have as their main application the preparation of modified emulsions of asphalt that impart torsional elastic recovery in the asphalt residue of the emulsion.

8. Method for preparing latices of aqueous polymeric emulsions, characterized in that the use of zinc oxide or calcium oxide, help as co-activators of the hydrocarbon resin to exert its function as a compatibilizer, since it reduces the particle size of the polymer to levels comprised in 2 and 15 micras by turbulent agitation and temperature control not higher than 45 ° C.

9. Method for preparing latices of aqueous polymeric emulsions, characterized in that their formation process is less than 10 hours.

10. Method for preparing latices of aqueous polymeric emulsions, characterized in that their formation process avoids foam formation and polymer losses.

11. Method for preparing latices of aqueous polymeric emulsions, characterized in that the aqueous polymeric emulsion formulated consists of a balance between its phases and does not require high energy consumption for its preparation.

12. Method for preparing latices of aqueous polymeric emulsions, characterized in that it provides the option of varying the mixture according to the desired application.