KR20000016607A - Water soluble dispersion solution based on silicon and organic (co)polymer latex substrate of silicon elastic polymer with controllable semi-transparency. - Google Patents

Abstract

PURPOSE: A water soluble dispersion solution based on a silicon compound and organic (co)polymer latex is subjected to cross-linking into elastic polymers having controllable semi-transparency by removal of water in a drying process. CONSTITUTION: The water soluble dispersion solution based on silicon and organic (co)polymer(s) comprises (A) an oil-in-water emulsion comprising 100 parts by weight of oil or α-ω-(dihydroxy)polydiorganic siloxane polymer(A1) and 1 to 100 parts by weight of organic silicon cross-linker(A2); (B) 100 parts by weight of a water soluble dispersion solution of at least one organic (co)polymer based on 100 parts by weight of oil or polymer(A1); and (C) 0.01 to 5 parts by weight of a catalyst metallic hardened compound based on 100 parts by weight of the oil or polymer(A1).

Description

Aqueous dispersions based on silicon and organic (co) polymer latexes for the production of silicon elastomers with adjustable translucency

The present invention relates to aqueous dispersions based on silicone compounds and organic (co) polymer latexes which can be crosslinked with elastomers with adjustable translucent by removal of water through drying under ambient conditions. The present invention also relates to its method of obtaining and its use in the construction industry to produce silicone elastomer products with adjustable translucent, such as, in particular, sealing and weathering mastices, exterior protective coatings and shells.

Aqueous dispersions based on silicones which can be crosslinked with translucent elastomers used in the manufacture of products for the building industry are already known in the art. Thus, in US-A-4,824,890, the basic aqueous dispersion comprises 5 to 30 parts by weight of silicone microemulsion (i) and colloidal silica having a particle size of less than 0.15 μm (150 nm) prepared by emulsion polymerization of cyclopolydiorganosiloxanes. (Per 100 parts of silicone polymer) (2i) and 1 to 5 parts by weight of dialkyltin dicarboxylate catalyst (per 100 parts of silicone polymer) (3i); In EP-A-0,542,498, the basic aqueous dispersion is the product of the crosslinking of alkoxysilanes with silicone oils containing silanol ends in the presence of a tin based catalyst having less than 10% of particles having a particle size of 1 μm (1000 nm). , From 0.7 to 2 parts by weight of a specific surfactant consisting of an aqueous emulsion of crosslinked silicone polymer (i) and an ammonium or alkali metal alkyl sulfate (per 100 parts by weight of crosslinked silicone polymer) (2i), and mechanical properties which make it useful in the construction industry. For the purpose of making the elastomeric product, it is a mixture of 2.5 to 45 parts by weight (per 100 parts by weight of silicone polymer) (3i) of colloidal silica used in the form of an aqueous dispersion with a particle size of less than 0.06 μm (60 nm).

Said aqueous dispersions which can be crosslinked with translucent elastomers nevertheless have disadvantages, among which mention may be made of:

Lack of stability in storage; This is because the system tends to produce gels due to the premature generation of condensation reactions that can occur between silicone polymers and colloidal silica, which are reactive via surface hydroxyl groups;

Semi-transparency, which is mainly adjustable only by adjusting the content of silicic acid feedstock; At present, any change in the silica content tends to substantially modify some of the essential properties of the elastomer, in particular mechanical fracture properties, elasticity and adhesion; Therefore, the translucency of the elastomer cannot be adjusted at the same time without modification of other essential properties.

In the present invention,

Is stable on storage because it is made from a component that does not contain a reactive feedstock such as colloidal silica,

The removal of water, on the one hand, has the advantage of having a translucency that can be adjusted independently of other properties, in particular mechanical properties, and on the other hand, it provides high mechanical properties despite the absence of reinforced inorganic fillers. Aqueous dispersions which can be crosslinked with elastomers having the advantage, which can be advantageously suited for the manufacture of products for construction industry, are commonly used as aqueous dispersions of the above general form which can be crosslinked with silicone elastomers by removal of water. It has been found that the resulting inorganic filler can be obtained by replacing the polymer feedstock in the form of an aqueous dispersion of organic (co) polymer (s).

For the purposes of the present invention, the expression "adjustable opacity" means that the opacity can be easily adjusted to cover the entire range from full opacity to high translucency close to transparency.

Mechanical properties relating to this specification are essential properties for the elastomer to ensure its action of lining joints, regardless of climatic conditions; Particularly at 100% elongation will be mentioned secant modules, elongation at break, fracture strength, elasticity and adhesion.

The use of a combination of silicone (s) and organic latex is already in EP-A-0,410,899 in the form in which reinforcing inorganic fillers are present in order to obtain an elastomeric product with high mechanical properties which is more opaque by removal of water. It is taught to maintain a moderate viscosity while increasing the solids content of the aqueous silicone dispersion.

In the subject matter of the present invention, any of the documents included in the prior art are polymeric feedstocks in order to obtain an elastomeric product that is adjustable translucent for the building industry while maintaining good mechanical properties without the use of reinforced inorganic fillers. Does not teach its use.

More specifically, the present invention consists of the absence of any strengthening inorganic filler and the following components, wherein the aqueous dispersion has a solids content of at least 60% by weight; The translucency of the elastomeric article formed is the desired value (s): the size of the polymer particles in the latex (B); Or the refractive index of the polymer constituting the latex (B) by modification of the chemical composition of the organic (co) polymer; Or simultaneously with adjustable semi-transparent elastomers having high mechanical properties by removal of water through drying under ambient conditions, characterized in that they are adjusted during the preparation of the aqueous dispersion by adjusting to the two variables, size and refractive index mentioned above. Aqueous dispersions based on the crosslinked silicone and organic (co) polymer (s):

(A): Oil-in-water emulsion based on 100 parts by weight of oil or α, ω- (dihydroxy) polydiorganosiloxane polymer (A1) and 1 to 100 parts by weight of organosilicon crosslinking agent (A2) (the emulsion is

Stabilized by at least one surfactant (A3) selected from anionic and nonionic surfactants and mixtures thereof,

Having a particle size of 0.1 μm (100 nm) to 100 μm (100,000 nm),

A solids content of at least 60% by weight);

(B): 1 to 100 parts by weight of an aqueous dispersion of at least one organic (co) polymer having the following per 100 parts by weight of oil or polymer (A1):

Particle size from 0.01 μm (10 nm) to 10 μm (10,000 nm);

Solids content from 10 to 70% by weight;

(C): optionally, 0.01 to 5 parts by weight of the catalytic metallic curing compound, per 100 parts by weight of oil or polymer (A1).

The final aqueous dispersion is prepared by simple contiguous mixing of all components, resulting in a stable homogeneous dispersion upon storage in the absence of air.

Those skilled in the art will appreciate the scattering force of the particles in the continuous medium (in this case the silicone matrix obtained after crosslinking phase (A) by removal of water), which controls the opacity of the elastomer (inversely to its translucency), in this case the latex (B) Polymer particles]

Particle size, and

It is known that it decreases with the difference in refractive index between the particles and the continuous medium.

The teaching follows the Rayleigh scattering law, which allows the scattering force Pd of the particles to be represented by the following equation:

Where x = 2 πr / λ (r = average radius of the particles and λ = wavelength of light), and m = n1 / n2 (n1 = refractive index of the particles and n2 = refractive index of the continuous medium).

Emulsion (A):

Oil or Polymer (A1):

The α, ω- (dihydroxy) polydiorganosiloxane should have a viscosity of at least 100 mPa · s, preferably at least 50,000 mPa · s at 25 ° C.

The reason for this is that obtaining an elastomer with a set of suitable mechanical properties is due to a viscosity in excess of 50,000 mPa · s, especially with regard to elongation and fracture strength at break.

In addition, the higher the viscosity, the more preservation of the mechanical properties during aging of the elastomer.

Preferred viscosities for the invention are 50,000 to 1,500,000 mPa · s at 25 ° C.

The viscosity referred to herein is the dynamic viscosity at 25 ° C .; It is measured using a Brookfield viscometer according to the instructions of AFNOR standard NFT 76102, May 1982.

Organic radicals of the α, ω- (dihydroxy) polydiorganosiloxanes are monovalent hydrocarbon based radicals containing up to 6 carbon atoms, optionally substituted with cyano or fluoro groups. Substituents commonly used because of their availability in industrial products are methyl, ethyl, propyl, phenyl, vinyl and 3,3,3-trifluoropropyl radicals. Typically, in number terms, at least 80% of the radicals are methyl radicals.

Crosslinker (A2):

As above, an organosilicon crosslinking agent is used. The section of recommended crosslinkers will follow with the correct amounts for each of them recommended in emulsion (A), taking into account the properties of the crosslinkers used, said amounts being expressed in parts by weight per 100 parts of oil or polymer (A1):

1 to 15 parts of organosiliconate;

1 to 100 parts of silsesquioxane resin microemulsion according to the combined teachings of US-A-3,355,406 and US-A-3,433,780;

5 to 100 parts of a low molecular weight reactive silicone resin containing alkoxy and acyloxy groups;

5 to 100 parts of high molecular weight toluene insoluble silicone resin;

5 to 100 parts of a hydroxysilicone resin containing at least two different units selected from those of the formula: R ₃ SiO _0.5 (M), R ₂ SiO (D), RSiO _1.5 (T) and SiO _{2 per} molecule (Q) [wherein R is mainly C ₁ -C ₆ alkyl, vinyl or 3,3,3-trifluoropropyl radicals and has a hydroxyl group weight content of 0.1 to 10%]. Among the above resins which are introduced by themselves or in the form of aqueous emulsions, mention may be made of the resins MQ, MDQ, TD and MTD;

Silanes 1-20 parts of the formula: R _a SiX _4-a [where R is a monovalent organic radical, in particular methyl or vinyl, a is 1 or 0, and X is alkoxy, acyloxy, ketiminoxy ( ketiminoxy), alkylamino, imido and alkenyloxy groups and various possible mixtures thereof, preferably condensable and / or hydrolyzable groups. When X is alkoxy, it is preferable to add 2-amino-2-methylpropanol as a stabilizer according to the teachings of EP-A-0,259,734.

The crosslinking agent (A2) used is preferably contained in 5 to 100 parts of the hydroxysilicone resin.

Surfactant (A3):

In the context of the present invention, the surfactant used may be selected from, for example, alkylbenzene sulfonates, alkyl sulfates, alkyl ether sulfates, alkylaryl ether sulfates and dioctyl sulfosuccinates of alkali metals, and mixtures thereof. Anionic surfactants that may be present. Preferred anionic surfactants are polybenzene sulfonates of alkali metals.

The surfactant used may also be nonionic; As examples, alkoxylated fatty acids, polyalkoxylated alkylphenols, polyalkoxylated fatty alcohols, polyalkoxylated or polyglycerolated fatty amides, polyglycerolated α-diols and alcohols, ethylene oxide / propylene oxide block polymers, ethylene jade Polydiorganosiloxanes containing siloxane units having seed chains or propylene oxide chains as well as alkyl glucosides, alkyl polyglucosides, sucroethers, sucrose esters, sucroglycerides, sorbitan esters, of said sugar derivatives Mention may be made of ethoxylated compounds and mixtures of these surfactants. Preferred nonionic surfactants are polyalkoxylated alkylphenols and polyalkoxylated fatty alcohols.

As a further preferred embodiment, a mixture of preferred nonionic surfactant (s) and one (or more) preferred anionic surfactant (s) can be used.

Alone or as a mixture, the surfactant is selected as a function of the nature of the silicone oil or polymer (A1) to be emulsified; An HLB of about 11 to 15 is preferably selected to emulsify the oil or polymer (A1) consisting of α, ω- (dihydroxy) polydiorganosiloxane.

Preparation of Emulsion A:

To prepare emulsion A, an emulsion polymerization process can be used which directly provides emulsion (A). However, this process makes it possible to obtain an emulsion (A) containing ultra high viscosity α, ω- (dihydroxy) polydiorganosiloxane without difficulty.

In the above process, oil-in-water in silicone phase is prepared by an anionic polymerization technique of oil (A1) having a low viscosity in the range of 100 mPa · s to 1000 mPa · s, wherein the polymerization is optionally carried out in another process, after polymerization And in the presence of a crosslinking agent (A2) which can also be added later. Such anionic polymerization processes are described in US Pat. No. US-A-2,891,920 and specifically US-A-3,294,725, incorporated by reference. The polymer obtained is anionic stabilized by a surfactant, preferably an alkali metal salt of a sulfonic aromatic hydrocarbon based acid, according to the teachings of US-A-3,294,725, the free acid also acting as polymerization catalyst.

Preferred catalysts and surfactants are dodecylbenzenesulfonic acid and alkali metal salts thereof, in particular sodium salts thereof. Other anionic or nonionic surfactants may optionally be added. However, this addition is not necessary because in US-A-3,294,725 the amount of anionic surfactant resulting from the neutralization of sulfonic acid is sufficient to stabilize the polymer emulsion. The amount is usually less than 3%, preferably 1.5% of the weight of the emulsion (A).

However, in the present invention, it is well known to those skilled in the art and described in the literature, starting with α, ω- (dihydroxy) polydiorganosiloxane prepolymerized in the presence of a crosslinking agent (A2) and then placing it in an aqueous emulsion. It is preferred to stabilize the emulsion with anionic and / or nonionic surfactants according to the methods described in detail in, for example, patents FR-A-2,064,563, FR-A-2,094,322, FR-A-2,114,230 and EP-A-0,169,098). .

In the above method, the α, ω- (dihydroxy) polydiorganosiloxane polymer (A1) is mixed with a crosslinking agent (A2) and an anionic and / or nonionic surfactant (A3) by simple stirring, and the interface It is possible for the active agent to be an aqueous solution, then water is added and if necessary the mixture is passed through a standard colloid mill to convert to a fine, homogeneous emulsion. The ground material obtained can be optionally diluted with an appropriate amount of water. An emulsion (A) is obtained which is stable upon storage, stabilized by anionic or nonionic surfactants.

The emulsion (A) prepared by emulsion emulsion or by disposing the silicone polymer (A1) in the emulsion is in the form of an oil-in-water emulsion having a solids content of at least 60% by weight and preferably from 80 to 98% by weight.

It should be noted that the highly viscous silicone polymer (A1) having a viscosity of more than 30,000 mPa · s can be advantageously emulsified using the method described in document WO-A-94 / 09058 (cited by reference), on the one hand , Aqueous phase, and on the other hand, are characterized by very precise control over the value of the proportion of the individual viscosities of the silicone phase.

The preparation of all or part of the emulsion (A) by emulsion polymerization technique or by the preferred technique of emulsion does not constitute disclosure from the specification of the present invention, and the polymerization or the emulsification of the (A1) and (A2) constituents Run directly in the presence of latex (B) starting in whole or in part.

Dispersion of Latex (B):

Latex (B)

Formation of the latex (B) of the aqueous suspension of polymer particles derived from emulsion (co) polymerization of polymerizable organic monomer (s).

The main polymerizable monomer consists of at least one main monomer selected from styrene (a), butadiene (b), acrylic ester (c) and vinyl nitrile (d). Acrylic ester term C ₁ ~C ₁₂ alkanols, preferably C ₁ ~C ₈ alkanes with the all-acrylic or methacrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, n- butyl acrylate , Isobutyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and isobutyl methacrylate.

Vinyl nitriles include those containing 3 to 12 carbon atoms, in particular acrylonitrile and methacrylonitrile.

Styrene may be partially or wholly replaced by α-methylstyrene or vinyltoluene.

In addition to the main monomers (a) to (d), it is possible to copolymerize some of the main monomers having up to 40% by weight of at least one other ethylenically unsaturated monomer or compound selected from the following:

(e): vinyl esters of carboxylic acids such as vinyl acetate, vinyl versatate or vinyl propionate;

(f): ethylenically unsaturated monocarboxylic and dicarboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid or fumaric acid;

(g): monoalkyl esters of the dicarboxylic acids and alkanols containing 1 to 4 carbon atoms in (f), and N-substituted derivatives thereof;

(h): unsaturated carboxylic acid amides such as acrylamide, methacrylamide, N-metholacrylamide or N-metallmethacrylamide;

(i): ethylenic monomers containing sulfonic acid groups and ammonium or alkali metal salts thereof, such as vinylsulfonic acid, vinylbenzenesulfonic acid, α-acrylamidomethylpropanesulfonic acid or 2-sulfoethylene methacrylate;

(j): ethylenically unsaturated monomers containing secondary, tertiary or quaternary amino groups or heterocyclic groups containing nitrogen, for example vinylpyridine, vinylimidazole, aminoalkyl (meth) acrylate and aminoalkyl ( Meth) acrylamides such as dimethylaminoethyl acrylate or methacrylate, di-tert-butylaminoethyl acrylate or methacrylate, dimethylaminomethylacrylamide or dimethylaminomethylmethacrylamide, as well as zwitter Ionic monomers such as sulfopropyl (dimethyl) aminopropyl acrylate;

(k): esters of (meth) acrylic acid and alkanediols, preferably containing 2 to 8 carbon atoms, such as glycol mono (meth) acrylate, hydroxypropyl mono (meth) acrylate or 1,4-butanediol mono (meth ) Acrylates, as well as monomers containing two polymerizable double bonds, such as ethylene glycol dimethacrylate.

In addition to the above monomers (e) to (k), unsaturated ethylenic monomers of crosslinkable nature, such as glycidyl (meth) acrylate (1) or vinyl and acrylic, in small amounts of 0.1 to 5% by weight relative to the total weight of the monomers. It is also possible to use silanes (m) such as vinyltrimethoxysilane and vinyltriethoxysilane.

In addition to the above monomers (e) to (m), at least one ethylenically unsaturated monomer (a) to (d) via a radical route is present in an amount in the range of 40% by weight or less based on the total weight of the ethylenically unsaturated monomer or compound. In addition, one or more ethylenically unsaturated functional groups (eg vinyl), which may optionally be reacted with one or more monomers (e) to (m), and optionally one or more other reactive functional groups (eg epoxidation or hydroxy functional groups) Or functionalized polyorganosiloxanes (n) with (meth) acrylic functional groups) can also be used (see in particular EP-A-0,635,526).

As dispersions (B) which can be used in the context of the present invention, mention will be made in particular of containing homopolymers derived from monomers (a), (c) and (e).

As copolymer latex (B), particular mention will be made of latexes containing copolymers derived from:

At least one monomer (a), at least one monomer (d) and at least one monomer (f);

At least one monomer (a) and at least one monomer (c);

At least two monomers of different properties (c);

At least one monomer (c) and at least one monomer (f);

At least one monomer (c), at least one monomer (e) and at least one monomer (g);

At least one monomer (c) and at least one monomer (e);

At least one monomer (c) and at least one monomer (m).

In the Rayleigh dispersion method, for a given silicone matrix, the translucency of the elastomer containing the polymeric feedstock (in this case a latex having a particle size of 0.01 μm (10 nm) to 0.06 μm (60 nm), for example) It has been observed that the polymer particles of B)) contain the same polymeric feedstock but in this case are always larger than those of the elastomer which is substantially larger particle size, ie greater than 0.06 μm (60 nm). It has also been observed that for a given size (small or large) of the particles in the polymeric feedstock, the translucency is always greatly improved by the reduction of the refractive index of the feedstock polymer, ie by the appropriate modification of the chemical composition of the polymer.

In a preferred embodiment of the invention, in order to provide a semitransparent elastomer which is adjustable in medium to expensive zones, latex (B) having the following is used:

Particle size 0.01 μm (10 nm) to 0.08 μm (80 nm), and preferably 0.02 μm (20 nm) to 0.06 μm (60 nm), and

Solid content of 10 to 50% by weight.

In a more preferred embodiment, which achieves the intended purpose of the translucency, latex (B) is used which has the small particle size and solids content and contains the following acrylic (co) polymers:

Acrylic homopolymers obtained from monomers (c), and

At least partially selected from the group formed by acrylic monomer (c) or at least one monomer (c) and monomer (f) taken as (meth) acrylic acid, monomer (h) taken as acrylic derivative and monomer (k) Copolymers obtained from at least one other acrylic monomer.

For copolymers partially derived from acrylic monomers (c) or (c) + (f) and / or (h) and / or (k), 70 to 99% by weight relative to the total weight of the monomers, and preferably To 80 to 99% by weight relative to the total weight of the monomers.

Of course, the mechanical properties of the latex (B) mostly depend on the monomer selected to produce them. The polymer constituting the latex (B) may have a glass transition temperature Tg -70 ° C to + 230 ° C.

In an even more preferred embodiment of the invention, the aqueous dispersion (B) used is a latex as defined above in the specification of the so-called "more preferred" embodiment, wherein the component acrylic polymer has a glass transition temperature of Tg +50 ° C to + 130 ° C. The selection of these Tg values makes it possible to obtain the maximum strengthening efficiency (higher value for the breaking characteristics).

The polymer constituting the latex (B) usually has a refractive index of 1.34 to 1.60. Has The refractive index is measured by the simplified Gladstone-Dale equation:

[Where x _i and Represents the volume fraction and refractive index of each component of the polymer (see the book Polymer Handbook, 1989, VI / 452 to VI / 461).

In the most particularly preferred embodiment of the invention, the aqueous dispersion (B) used is the refractive index of the polymer Which is as defined above in the specification of the so-called "more preferred" embodiment, which is 1.34 to 1.50.

In a different embodiment of the present invention, to provide an elastomer having an adjustable translucent in a zone of a value substantially less than the mid to expensive zone previously mentioned with respect to a preferred embodiment of the present invention,

Particle size values greater than 0.08 μm (80 nm) to 10 μm, and preferably greater than 0.08 μm (80 nm) to 2 μm; And a solids content of 30 to 70% by weight;

Use of latex (B) containing acrylic (co) polymers as defined above in the specification of the so-called "more preferred" embodiments.

In different and preferred embodiments of the present invention, the aqueous dispersion (B) used is a latex as defined above in the specification of the so-called "different" embodiments, wherein the component acrylic polymer has a glass transition temperature of Tg +50 ° C to + 130 ° C.

In a different and more preferred embodiment, the aqueous dispersion (B) used is the refractive index of the polymer. Which is the latex as defined above in the specification of the so-called "different and preferred" embodiments, which are from 1.34 to 1.50.

Preparation of Latex (B)

One skilled in the art knows how to produce the latex (B). There are several ways to prepare aqueous dispersions of organic polymers;

By radical polymerization in emulsion;

By direct polymerization of the microemulsion of the corresponding monomer (s);

By evaporation of the emulsion and solvent (the process dissolves the polymer in a water-immiscible solvent having a boiling point below the boiling point of water, and then emulsifies the polymer solution in water and then evaporates the solvent Consists of removing);

By precipitation in a nonsolvent (the method consists in dissolving the polymer in a water immiscible solvent and then precipitating the polymer from water);

By coacervation (the method starts with a homogeneous solution to obtain phase-demixing with the formation of a (polymer rich) colloidal phase by modification of physical factors such as pH or temperature). It is possible to obtain a dispersion).

The method preferably used for the production of the latex (B) corresponding to the specification of the present invention is a method by radical polymerization in an emulsion.

As for the latex (B) of small particle size of 0.01 μm (10 nm) to 0.08 μm (80 nm), which are used in the specification of the preferred embodiment of the present invention, they are EP-A-0,644,20

Prepared by the more preferred radical polymerization method, which relates to the progressive introduction of monomer (s) into the aqueous reaction medium and also to the selective introduction of free radical initiator (s) described in 5 (cited by reference).

Metallic Curing Compound (C):

In particular, compounds (C) for optional crosslinking agents (A2) such as siliconates are optional, but in the context of the present invention, it is recommended to use (C).

The catalytic metallic curing compound (C) is essentially a carboxylate and a halide of a metal selected from lead, zinc, zirconium, titanium, iron, tin, barium, calcium and manganese.

The component (C) is preferably a catalyst tin compound, usually organotin salt, introduced in the form of an aqueous emulsion. Organotin salts that can be used are described in particular in the book, Chemistry and Technology of Silicones Academic Press (1968), page 337 by Noll. The emulsion can be stabilized, for example, with polyvinyl alcohol if necessary.

The reaction products of alkyl silicates or aryltrialkoxysilanes with dibutyltin diacetate can also be used as described in Belgian patent BE-A-842,305.

Preferred tin salts are tin bischelates (EP-A-0,147,323 and EP-A-0,235,049), diorganotin dicarboxylates, and in particular dibutyltin or dioctyltin diversatates (British patent GB-A). -1,289,900), dibutyltin or dioctyltin diacetate, and dibutyltin or dioctyltin dilaurate. 0.01 to 3, preferably 0.05 to 2 parts of the metallic curing compound (C) per 100 parts of (A1) is used.

Other optional additives:

The aqueous dispersions according to the invention may also contain one or more additive (s), such as in particular:

(D): optionally from 0.1 to 20 parts by weight of adhesive per 100 parts by weight of oil or polymer (A1);

(E): optionally, 0.1 to 5 parts by weight of nonionic, anionic or cationic organosilicon surfactant per 100 parts by weight of oil or polymer (A1);

(F): optionally, antifungal, antifoam, antifreeze such as ethylene glycol and propylene glycol, and thixotropic agents such as carboxymethylcellulose and xanthan gum.

Preferably, the adhesive (D) is amino, ureido, isocyanato (iso-

cyanato), an organic group (1) substituted with a radical selected from the group of epoxy, alkynyl, isocyanurate, hydantoyl and mercapto ester radicals and hydrolyzable groups linked to silicon atoms ( 2) organosilicon compounds having both.

For demonstration purposes, mention may be made of the organosilicon compounds (D) corresponding to the following formulas (with the patent number described):

Preferably, the organosilicon surfactants (E) are ethylene oxide or propylene oxide chains (in preparations of this type are sold under the tradename Tegopren, type 30, 58 or 70 from the company Goldschmidt). Commercially available), or amino chloride groups (the formulations of this type are also commercially available from Goldschmidt under the tradename tegoprene, type 69), or metal sulfonate groups (see, in this regard, books: Surface Functionalized with Phenomena and Additives in Water-Based Coatings and Printing Technology; edited by M.K. Sharma, Plenum Publisher, New York, 1991, pages 73-82. Polyorganosiloxanes.

Preparation of Aqueous Dispersion of the Invention

To prepare an aqueous dispersion according to the invention, the dispersion (B) is first added at room temperature with stirring to the emulsion (A), and then optionally in the form of an aqueous dispersion or emulsion, the metallic curing catalyst (C), and optionally the additive (s) ) It is recommended to add (D), (E) and / or (F). It is recalled that it is possible to effect the emulsion polymerization or emulsification of the emulsion (A) in part or in whole in the presence of the dispersion (B).

The pH of the aqueous dispersion can be acidic, neutral or basic. However, it is recommended to adjust the pH of the dispersion to a value greater than 7, preferably 8 to 13, with a strong organic base, or preferably a strong inorganic base (triethanolamine, and preferably sodium and potassium hydroxide).

The final dispersion obtained is homogenized, then degassed and then packaged in a leak-tight wrap in atmospheric oxygen and water vapor.

Components (A), (B), (C) and optionally (D), (E) and / or (F) to a degree such that the final emulsion has a solids content of at least 60% by weight, preferably 80-95% by weight. Mix in amounts.

To determine the solids content, 2 g of the dispersion are placed in an aluminum weight crucible and heated at 50 ° C. for 3 hours in an oven while circulating dry air. After cooling, the crucible is weighed again to determine the percentage of material remaining in addition to the initial 2 g, which represents the solids content.

In a preferred variable, after preparing a dispersion according to the invention, the dispersion is subjected to a aging step of several hours to several days at room temperature.

The aging step simply consists of leaving the dispersion in the absence of atmospheric oxygen before use.

The dispersion according to the invention translucent silicone elastomeric products, in particular the sealing and weatherproofing mastics, and in the building industry for producing a shell for weather and water-resistant coating or the exterior for when building outer wall contact for the outer wall to be treated contains m ² dispersion 20 to per It can be used in a capacity of 100 g.

Later examples will demonstrate the invention without limiting its scope.

Example 1 (comparative):

An emulsion (A) is prepared by introducing the following into a 5 liter Meili mixer with a striking rod:

1000 g of α, ω- (dihydroxy) polydimethylsiloxane oil having a viscosity of 80,000 mPa · s at 25 ° C .;

Hydrogen introduced as it is, containing 0.5% by weight of hydroxyl groups, consisting of 62% by weight of CH ₃ SiO _1.5 units, 24% by weight of (CH ₃ ) ₂ SiO units and 14% by weight of _0.5 units of (CH ₃ ) ₃ SiO. 60 g of oxysilicone resin; The resin is soluble in toluene and has a molecular weight of about 1000 and a CH ₃ / Si molar ratio of 1.5;

45 g of Genapol X080 sold by the company Hoechst, which is a nonionic surfactant, ie a polyalkoxylated (containing about 13 ethylene oxide units) fatty alcohol (containing 13 carbon atoms); And

35 g of water.

The final mixture obtained is homogenized for 180 minutes.

The obtained emulsion A has an average particle size of 0.5 μm (500 nm) and a solids content of 96.9 wt%.

While stirring for 10 minutes for each of the following components, the following components are incorporated in the same mixer in emulsion (A):

Dispersant 13 in the form of an aqueous solution containing 280 g of precipitated CaCO ₃ , 40% by weight of polysodium acrylate, having an average particle size of 0.07 μm (70 nm), ie a volume equivalent to the particle size in the polymeric feedstock of the later examples. an aqueous dispersion of precipitated CaCO ₃ with a solids content of 43.6%, consisting of g and 323 g of water;

10 g of an aqueous emulsion containing 38% by weight di-n-octyltin dilaurate stabilized with 5% by weight polyvinyl alcohol relative to tin salt; And

22 g of aqueous potassium hydroxide solution with a solid content of 50%.

The final dispersion has a pH 12 and a solids content of 81.3% by weight.

After 4 days of storage, samples are prepared for use in evaluating later target properties:

Mechanical properties of fracture and modulus:

The dispersion was spread on a teflon plate with a scraper paddle to make the film 2.5 mm thick and left to dry for 7 days in an air conditioning chamber (temperature 23 ° C. ± 2 ° C .; relative humidity: 55% ± 5%). do.

The following properties are evaluated on a test piece H2 cut from the dry film:

Elongation at break (EB,%) and breaking strength (BS, MPa) as instructed by AFNOR standard T-46002,

Elastic modulus (E,%) of the mastic by relaxation test under the following conditions: 100% elongation of the sample at a rate of 30 mm / min, followed by relaxation of the sample elongated for 15 minutes. Elastic modulus as% is assessed by Equation 100 (1-C ₁₅ / C ₀ ), which is the constraint that C ₀ and C ₁₅ suffer from the sample on elongation pause (C ₀ ) and after 15 minutes (C ₁₅ ). Modulus of elasticity is evaluated as the average of three test samples.

Translucency:

A flat bottom crucible with a depth of 4 mm is filled with the dispersion and the aggregates are dried for 10 days in an air conditioning chamber (temperature 23 ° C. ± 2 ° C .; relative humidity: 55% ± 5%).

The translucency of a sample is measured by its contrast ratio (CR,%) on a black and white background. The ratio is evaluated with a data color machine sold by Datacolor machine under the following light conditions: Luminance C ₁₀ with diffuse light, anti-UV and anti-glare filters. Translucency is evaluated by the contrast ratio CR = Y black background / Y white background × 100 (%), disposed on a black and white background, respectively, ie CR / 100 is 3 of the light reflected at 90 ° C. by the elastomer sample. The ratio of Y (green light) of the color coordinates.

Adhesive:

The adhesive (A, Newton) of the elastomer was dried for 7 days at 23 ° C. ± 2 ° C. and 55% ± 5% relative humidity, and then 50 mm / min on a transparent glass support of 25 mm wide mastic film. It is evaluated by the T peel test at an angle of 180 ° at speed.

The film of mastic is reinforced with nylon-66 mesh mesh polyamide fibers in the following manner: a first film of 1.5 mm thickness is attached, and the polyamide strip is unpacked thereto; A second layer of aqueous silicone dispersion is attached onto the aggregate using a 2.5 mm scraper paddle to form a mastic-polyamide-mastic sandwich structure.

All measured properties are shown in Table 2 below.

Examples 2-7 (according to the invention)

The same procedure as in Example 1 above was carried out, except that the aqueous CaCO ₃ dispersion was immediately replaced with 330 g of particulate sized latex (B).

Characteristic of the nanolatex used:

Example Composition (% by weight) Solid content (% by weight) Average size nm Tg (° C) (2) (3) MMA STY BuA MAA VTEO 2 90 0 0 10 0 30 40 114 1.493 3 35 0 55 10 0 30 40 One 1.480 4 0 0 90 10 0 30 40 -42 1.472 5 100 0 0 0 0 30 40 105 1.489 6 95 0 0 0 5 30 40 105 1.489

(1) MMA = methyl methacrylate; STY = styrene; BuA = butyl acrylate; MAA = methacrylic acid; VTEO = vinyltriethoxysilane.

(2) Tg is evaluated by differential scanning calorimetry (or DSC) analysis according to the instructions of AFNOR standard T 51-5077.

(3) the refractive index of the (co) polymer : From the refractive index of the homopolymer according to the Gladstone-Dale addition rule: Polystyrene = 1.591, Polyacrylic acid = 1.527, Polymethyl methacrylate = 1.485, Polybutyryl acrylate = 1.4666.

General manufacturing method of nano latex:

Continuously, 0.5 g of an aqueous solution containing 3 g of sodium lauryl sulfate, 240.3 g of water and 30% by weight of ammonium persulfate were continuously fed into a 1 liter stainless steel reactor equipped with a stirrer and a circulating jacket of water for temperature control inside the reactor. It is introduced. The reactor contents are then brought to a temperature of 90 ° C. and then 100 g of a mixture of ethylenically unsaturated monomers are introduced continuously for 2 hours. The dispersion is then cooled and filtered.

A blue-gray latex is obtained having a solids content of 30% by weight and an average particle size of 0.04 μm (40 nm).

The final dispersions of Examples 2-7 obtained have a pH 12 and a solids content of 81.3%.

The properties of the reference elastomer with carbonate as well as the properties of the elastomer reinforced with nanolatex are shown in Table 2 below:

CR (%) EB (%) BS (MPa) E (%) A (N) Example 1 (comparative) 100 935 0.75 26.5 0.1 Example 2 93.0 930 0.89 29.2 0.5 Example 3 88.6 675 0.50 21.3 0.1 Example 4 76.3 640 0.33 26.8 0.1 Example 5 87.9 935 0.51 30.6 10 Example 6 90.0 730 0.77 42.9 15

Compared with carbonate-reinforced elastomers, elastomers reinforced with nanolatex are small, notably more translucent with comparable mechanical properties, if not good.

Claims (18)

Free of any reinforced inorganic filler and the following components, the aqueous dispersion having a solids content of at least 60% by weight; The translucency of the elastomeric article formed is the desired value (s): the size of the polymer particles in the latex (B); Or the refractive index of the polymer constituting the latex (B) by modification of the chemical composition of the organic (co) polymer; Or simultaneously with adjustable semi-transparent elastomers having high mechanical properties by removal of water through drying under ambient conditions, characterized in that they are adjusted during the preparation of the aqueous dispersion by adjusting to the two variables, size and refractive index mentioned above. Aqueous dispersions based on the crosslinked silicone and organic (co) polymer (s): (A): Oil-in-water emulsion based on 100 parts by weight of oil or α, ω- (dihydroxy) polydiorganosiloxane polymer (A1) and 1 to 100 parts by weight of organosilicon crosslinking agent (A2) (the emulsion is Stabilized by at least one surfactant (A3) selected from anionic and nonionic surfactants and mixtures thereof, Having a particle size of 0.1 μm (100 nm) and 100 μm (100,000 nm), A solids content of at least 60% by weight); (B): 1 to 100 parts by weight of an aqueous dispersion of at least one organic (co) polymer having the following per 100 parts by weight of oil or polymer (A1): Particle size from 0.01 μm (10 nm) to 10 μm (10,000 nm); Solids content from 10 to 70% by weight; (C): optionally, 0.01 to 5 parts by weight of the catalytic metallic curing compound, per 100 parts by weight of oil or polymer (A1). The method according to claim 1, wherein the α, ω- (dihydroxy) polydiorganosiloxane (A1) has a viscosity of at least 50,000 mPa · s at 25 ° C. and the organic radicals of the siloxane are optionally substituted with cyano or fluoro groups. A monovalent hydrocarbon based radical containing 6 or less carbon atoms. The dispersion according to claim 1 or 2, wherein the crosslinking agent (A2) is selected from: Organosiliconate; Silsesquioxane resin microemulsion resins; Low molecular weight reactive silicone resins containing alkoxy and acyloxy groups; High molecular weight toluene insoluble silicone resins; Hydroxysilicone resins containing at least two different units selected from the following formulas per molecule: R ₃ SiO _0.5 (M), R ₂ SiO (D), RSiO _1.5 (T) and SiO ₂ (Q), wherein R Is a C _{1 to} C ₆ alkyl, vinyl or 3,3,3-trifluoropropyl radical and has a hydroxyl group weight content of 0.1 to 10%]; Silanes of the formula: R _a SiX _4-a where R is a monovalent organic radical, in particular methyl or vinyl, a is 1 or 0, X is alkoxy, acyloxy, ketiminoxy, alkylamino, amino Condensable and / or hydrolyzable groups, preferably selected from Fig. And alkenyloxy groups and various possible mixtures thereof. The method according to any one of claims 1 to 3, (Co) polymerization of at least one main monomer selected from styrene (a), butadiene (b), acrylic ester (c) and vinyl nitrile (d), Aqueous dispersions, characterized in that some of the main monomers (a) to (d) can be copolymerized to 40% by weight or less of one or more other monomers or unsaturated compounds selected from the group formed by Dispersion characterized in that (B) contains an organic (co) polymer derived from: (e): vinyl esters of carboxylic acids; (f): ethylenically unsaturated monocarboxylic and dicarboxylic acids; (g): monoalkyl esters of the dicarboxylic acids and alkanols containing 1 to 4 carbon atoms in (f), and N-substituted derivatives thereof; (h): unsaturated carboxylic acid amide; (i): an ethylene monomer containing a sulfonic acid group and an ammonium or alkali metal salt thereof; (j): zwitterionic monomers as well as ethylenically unsaturated monomers containing secondary, tertiary or quaternary amino groups or heterocyclic groups containing nitrogen; (k): esters of (meth) acrylic acid with alkanediols, preferably containing 2 to 8 carbon atoms, as well as monomers containing two polymerizable double bonds; (l): glycidyl methacrylate; (m): vinyl or acrylic silane; (n): functionalized polyorganosiloxanes having at least one ethylenically unsaturated functional group capable of reacting with another ethylenically unsaturated monomer via a radical pathway. Dispersion according to any one of claims 1 to 4, characterized in that a latex (B) is used for the purpose of producing an elastomer having a translucent adjustable in a medium to expensive zone. Particle size from 0.01 μm (10 nm) to 0.08 μm (80 nm); And Solid content of 10 to 50% by weight. The method of claim 5 wherein: The aqueous dispersion or latex (B) contains: Acrylic homopolymers obtained from monomers (c), and At least partially selected from the group formed by acrylic monomer (c) or at least one monomer (c) and monomer (f) taken as (meth) acrylic acid, monomer (h) taken as acrylic derivative and monomer (k) Copolymers obtained from at least one other acrylic monomer; In the case of copolymers partially derived from acrylic monomers (c) or (c) + (f) and / or (h) and / or (k), from 70 to 99% by weight of acrylic relative to the total weight of the monomers Dispersion, characterized in that the amount of the monomer is used. A dispersion according to claim 6, wherein the aqueous dispersion (B) contains an acrylic organic (co) polymer having a glass transition temperature of Tg + 50 ° C to + 130 ° C. 8. The aqueous dispersion (B) according to claim 7, wherein the aqueous dispersion (B) is Tg + 50 ° C to + 130 ° C and has a refractive index. Dispersion, characterized in that it contains an acrylic organic (co) polymer of 1.34 to 1.50. 4. A process according to any one of claims 1 to 3 for the purpose of producing elastomers having translucent properties which are adjustable in the medium to expensive zones already mentioned in claim 5, Having a particle size at a value of greater than 0.08 μm (80 nm) to 10 μm; Has a solids content of 30 to 70% by weight; A dispersion characterized in that a latex (B) containing an acrylic (co) polymer as defined in claim 6 is used. 10. The dispersion according to claim 9, wherein the aqueous dispersion (B) contains an acrylic organic (co) polymer having a glass transition temperature of Tg + 50 ° C to + 130 ° C. The aqueous dispersion (B) according to claim 10, wherein the aqueous dispersion (B) is Tg + 50 ° C to + 130 ° C and has a refractive index. Dispersion, characterized in that it contains an acrylic organic (co) polymer of 1.34 to 1.50. 9. The aqueous dispersion according to claim 5, wherein the latex B has a particle size of 0.02 μm (20 nm) to 0.06 μm (60 nm). 12. The aqueous dispersion according to claim 9, wherein the latex B has a particle size of greater than 0.08 μm (80 nm) to 2 μm. The method according to any one of claims 1 to 13, The emulsion (A) has a solids content of 80 to 98% by weight; Aqueous dispersion, wherein the final aqueous dispersion has a solids content of 80 to 95% by weight. The aqueous dispersion according to any one of claims 1 to 14, characterized in that the metallic compound (C) is an organotin salt in the form of an aqueous emulsion. The dispersion (B) is first added to the emulsion (A) at room temperature, and then the metallic curing catalyst (C) and the optional additive (s) are optionally added in the form of an aqueous dispersion or emulsion. Process for the preparation of an aqueous dispersion according to claim 15. 17. The method of claim 16, wherein the pH of the final aqueous dispersion is adjusted to a value greater than 7 by the addition of strong inorganic bases. Use of an aqueous dispersion according to any of claims 1 to 16 in the construction industry for the production of semi-transparent silicone elastomeric products consisting of sealing and weather resistant mastices, protective coatings and exterior shells.