KR19980063275A - Self-crosslinking Paint Formulations - Google Patents

Abstract

The present invention relates to the synthesis of latexes which can be used to prepare water-reducible self-crosslinkable coating compositions, such as paints, which contain no or very little volatile organic compounds. Paints formulated using the latex of the present invention not only have good solvent resistance, flexibility and ultraviolet light resistance but also provide environmental benefits. More specifically, the present invention discloses a water-reducible coating composition consisting of the following (1) to (4): (1) water; (2) about 30 to about 75 weight percent of vinyl aromatic monomer, (b) about 20 to about 65 weight percent of alkyl acrylate monomer, and (c) about 1 to about alkyl propene acid monomer, based on 100 weight percent of monomer About 8 weight percent, and (d) a resin having a repeating unit derived from about 0.5 to about 5 weight percent of an acryloxyalkenyltrialkoxysilane monomer; (3) hydrating agents; And (4) defoamers. Gamma-methacryloxypropyltrimethoxysilane is a representative example of the most preferred acryloxyalkenyl-trialkoxysilane monomers.

Description

Self-crosslinking Paint Formulations

Most conventional paint resins are water insoluble. Thus, in common practice, these resins were dissolved in a suitable organic solvent or dispersed in water with the aid of an emulsifier or surfactant to provide a coating composition suitable for application to the substrate surface. A serious drawback of organic solvent solutions is that they are potentially toxic, flammable and environmental contaminants. Water-reducible paints greatly reduce these problems. For this reason, water-based paints are commonly used as oil-based paint substitutes in many applications.

Various water-reducing paint resins, such as those described in US Pat. No. 4,474,926, have been developed. Water-reducible paints using these resins have been developed for a variety of purposes and have been widely accepted for many applications such as highway stripe paint.

U. S. Patent No. 4,968, 741 describes a coating for a metal substrate with improved corrosion and rust resistance. Such paints are of the water-reducible type and can be advantageously used in the automotive industry and other applications where good rust resistance is required. For example, these paints are excellent for painting bridges and other outdoor metal structures.

It is also important that paints prepared using water-reducible paint formulations provide the desired combination of physical and chemical properties. For example, in many applications, it is important that paints exhibit excellent flexibility, excellent ultraviolet light resistance and good solvent resistance. Excellent corrosion and rust resistance is also typically required for applications involving metal substrates.

For the purposes of the present invention, aqueous coating systems are considered to be colloidal dispersions of resins in water which can be reduced by hydrogenation and form a durable coating upon application to the substrate surface. The term aqueous paint system is used herein interchangeably with the term water-reducible paint. Other names that may be applied to water-reducing paints are water-soluble, water-soluble and water-dilutable.

The present invention relates to the synthesis of latexes that can be used to prepare self-crosslinkable water-reducible paint compositions such as paints, providing good solvent resistance, reduced drying time and improved adhesion to metals and glasses. Paints formulated using the latex of the present invention are also environmentally beneficial because they contain no or very few volatile organic compounds and additionally provide excellent flexibility and excellent ultraviolet light resistance.

More specifically, the present invention discloses a water-reducible coating composition consisting of the following (1) to (4): (1) water; (2) about 30 to about 75 weight percent of vinyl aromatic monomer, (b) about 20 to about 65 weight percent of alkyl acrylate monomer, and (c) about 1 to about alkyl propene acid monomer, based on 100 weight percent of monomer About 8 weight percent, and (d) a resin having a repeating unit derived from about 0.5 to about 5 weight percent of an acryloxyalkenyltrialkoxysilane monomer; (3) hydrating agents; And (4) defoamers.

The present invention also discloses a process for the preparation of neutralized latexes useful for the preparation of self-crosslinkable water-reducible paints comprising the following steps (1) and (2): (1) Based on 100% by weight monomer. (a) about 30 to about 75 weight percent of vinyl aromatic monomer, (b) about 20 to about 65 weight percent of alkyl acrylate monomer, (c) about 1 to about 8 weight percent of alkyl propene acid monomer, and (d) acrylic The monomer mixture comprising about 0.5 to about 5 weight percent of the oxyalkenyltrialkoxysilane monomer is polymerized by free radical aqueous emulsion polymerization at a pH of less than about 3.5 in the presence of at least about 0.2 to 3 phm of one or more alpha-olefin sulfonate soaps. Manufacturing; And (2) neutralizing the latex with ammonia to a pH range of about 7 to about 10.5 to produce a neutralized latex.

The present invention also discloses latexes useful for the preparation of self-crosslinkable water-reducible paints, consisting of the following (1) to (3): (1) water; (2) emulsifiers; And (3) about 30 to about 75 weight percent of a vinyl aromatic monomer, (b) about 20 to about 65 weight percent of an alkyl acrylate monomer, (c) about 1 to about 8 weight percent of an alkyl propene acid monomer, and ( d) a polymer consisting of repeating units derived from about 0.5 to about 5 weight percent of an acryloxyalkenyltrialkoxysilane monomer.

The latex of the present invention is prepared by free radical emulsion polymerization. The fill composition used to prepare the latex of the present invention contains a monomer, at least one alpha-olefin sulfonate surfactant and at least one free radical initiator. The monomer fill composition used for such polymerization may comprise (a) about 30 to about 75 weight percent of vinyl aromatic monomers, (b) about 20 to about 65 weight percent of alkyl acrylate monomers, and (c) about 1 to about 8 alkyl propene acid monomers. Weight percent, and (d) about 0.5 to about 5 weight percent of an acryloxyalkenyltrialkoxysilane monomer.

Preferably, the polymer is about 40 to about 70 weight percent vinyl aromatic monomer, about 25 to about 55 weight percent alkyl acrylate monomer, about 1.5 to about 5 weight percent alkyl propene acid monomer, and (d) acryloxyalkenyltrialkoxy And from about 1 to about 3 weight percent of silane monomers. More preferably, the polymer is about 63 to about 67 weight percent vinyl aromatic monomer, about 27 to about 31 weight percent alkyl acrylate monomer, about 2 to about 4 weight percent alkyl propene acid monomer, and acryloxyalkenyltrialkoxysilane monomer About 1.5 to about 2 weight percent.

Representative examples of vinyl aromatic monomers that can be used include styrene, alpha-methyl styrene and vinyl toluene. Preferred vinyl aromatic monomers are styrene and alpha-methyl styrene. The most preferred vinyl aromatic monomer is styrene because it is relatively inexpensive.

Alkyl acrylate monomers that may be used have alkyl moieties having 2 to about 10 carbon atoms. The alkyl acrylate monomers preferably have alkyl residues having 3 to 5 carbon atoms. Most preferred alkyl acrylate monomers are n-butyl acrylate.

Alkyl propene acid monomers that can be used have the general formula:

[Formula 1]

Where

R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

Thus, the R group can be represented by the formula -C _n H _{2n + 1} , wherein n is an integer from 0 to 4. Representative examples of alkyl propene acid monomers that can be used include acrylic acid, methacrylic acid (2-methylpropenic acid), 2-ethylpropenic acid, 2-propylpropenic acid and 2-butylpropenic acid. Preferred alkyl propene acid monomers are acrylic acid and methacrylic acid.

In most cases, it is advantageous to use a combination of both acrylic acid and methacrylic acid as the unsaturated carbonyl compound component used in latex production. For example, using from about 1 to about 3 weight percent acrylic acid with about 0.5 to about 1.5 weight percent methacrylic acid produces a latex with improved freeze-thaw stability. For example, using about 2% acrylic acid with 1% methacrylic acid as an unsaturated carbonyl compound component yields a latex that can withstand at least 5 cycles of freeze-thaw. It is important that latex transported through cold regions have such improved freeze-thaw stability.

Acryloxyalkenyltrialkoxysilane monomers that can be used have the formula:

[Formula 2]

Where

R ¹ is a hydrogen atom, a methyl group (-CH ₃ ) or an ethyl group (-CH ₂ -CH ₃ ), wherein n represents an integer of 0 to 10;

R ² , R ³ and R ⁴ may be the same or different and are selected from alkyl groups having 1 to 3 carbon atoms.

It is preferable that R ¹ is a hydrogen atom or a methyl group. Most preferably, R ¹ is a methyl group. It is preferable that n is an integer of 2-4, and it is most preferable that it is 3. It is preferable that R <^2> , R <^3> and R <^4> are a methyl group or an ethyl group, and it is most preferable that they are a methyl group. Most preferred acryloxyalkenyltrialkoxysilanes are gamma-methacryloxypropyltrimethoxysilanes having the formula

[Formula 3]

The fill composition used to prepare the latex of the present invention contains a substantial amount of water. The ratio between the fill composition and the total amount of monomers present in the water may range from about 0.2: 1 to about 1.2: 1. It is usually preferred that the ratio of monomer to water in the fill composition is in the range of about 0.8: 1 to about 1.1: 1. For example, it is very satisfactory to use about 1: 1 ratio of monomer to water in the fill composition.

The fill composition also contains about 0.2 to about 3 phm (per 100 parts of monomer) of one or more alpha-olefin sulfonate soaps. It is usually preferred that the alpha-olefin sulfonate surfactant is present in the polymerization medium in an amount ranging from about 0.4 to about 2 phm. It is usually more preferred that the fill composition contains from about 0.5 to about 1 phm of alpha-olefin sulfonate soap.

The higher the amount of alpha-olefin sulfonate soap used in the polymerization medium, the more stable the latex is. However, when the amount of the surfactant used increases, flushing of the final coating also increases, resulting in less rust and corrosion resistance.

The free radical aqueous emulsion polymerization used to prepare the latex of the present invention is initiated by one or more free radical generators. Free radical generators are usually used at concentrations ranging from about 0.01 to about 1 phm. Common free radical initiators include potassium persulfate, ammonium persulfate, benzoyl peroxide, hydrogen peroxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, decanoyl peroxide, la Uryl peroxide, cumene hydroperoxide, p-mentane hydroperoxide, t-butyl hydroperoxide, acetyl peroxide, methyl ethyl ketone peroxide, succinic peroxide, dicetyl peroxydicarbonate, t-butyl peroxyacetate, various peroxy compounds such as t-butyl peroxymaleic acid, t-butylperoxybenzoate, acetyl cyclohexyl sulfonyl peroxide and the like; 2-t-butylazo-2-cyanopropane, dimethyl azodiisobutyrate, azodiisobutyronitrile, 2-t-butylazo-1-cyanocyclohexane, 1-t-amylazo-1-sia Various azo compounds such as nocyclohexane; And various alkyl perketals such as 2,2-bis- (t-butyl-peroxy) butane and the like. Water-soluble peroxygen-free radical initiators are particularly useful for such aqueous polymerizations.

The emulsion polymerization of the present invention is typically carried out at temperatures in the range of about 125 ° F. (52 ° C.) to 190 ° F. (88 ° C.). At temperatures above about 190 ° F. (88 ° C.), alkyl acrylate monomers such as butyl acrylate tend to boil. Thus, a pressure jacket is required to heat such acrylate monomers to temperatures above about 88 ° C. On the other hand, the polymerization proceeds very slowly at temperatures below about 125 ° F. (52 ° C.). Slow polymerization at temperatures below about 125 ° F. (52 ° C.) resulted in polymers with non-uniform distribution of repeat units in the backbone. This slow rate of polymerization proceeds at low temperatures is also undesirable because it greatly reduces the throughput of the polymerization reactor.

The polymerization temperature is usually preferably maintained in the range of about 150 ° F. (66 ° C.) to 180 ° F. (82 ° C.). It is usually more desirable to control the reaction temperature within the range of about 160 ° F. (71 ° C.) to about 170 ° F. (77 ° C.). It is important that the polymerization is carried out at a pH of less than about 3.5 so that no water-sensitive polymer is produced. It is desirable to maintain the pH of the polymerization medium to about 3.0 or less throughout the polymerization. As the polymerization proceeds, the pH of the polymerization medium naturally drops. Thus, good results can be obtained by adjusting the pH of the initial polymer fill composition to within the range of about 3.0 to about 3.5 and proceeding with the polymerization. In this case, the final pH of the polymerization medium is about 1.5 which is quite satisfactory.

In commercial operation, it is usually desirable to add about 15 to about 25% monomer in the initial charge. The initial charge is then reacted for about 30 to about 60 minutes. Subsequently, the monomer residue to be charged can be continuously charged into the reaction zone at a rate sufficient to maintain the reaction temperature within a desired range. Highly uniform polymers can be prepared by continuously adding monomers to the reaction medium while maintaining a relatively constant reaction temperature.

According to the method of the present invention, the synthesized latex is neutralized with ammonia within the range of about 7 to about 10.5 pH. It is usually preferred to neutralize the latex within a range of pH 8 to 10, more preferably to neutralize within a range of about 9.0 to about 9.5. This can be done by simply dispersing ammonia throughout the latex to produce a neutralized latex. Ammonia is typically in the form of ammonium hydroxide.

The latex formed can be diluted to the desired concentration (solid content) with additional water. This latex can be used to prepare water-reducing paints using techniques known to those skilled in the art. In general, various pigments and plasticizers are added to the latex in the preparation of water-reducible paints. In the case of a water-reducing resin, there may be a problem of poor adhesion. Bonding the paint made by the water-reducing resin to the substrate can be greatly improved by adding a plasticizer.

Film-forming water-reducing compositions such as paints can be prepared by mixing latex, one or more pigments and plasticizers. It is not necessary to include coalescing solvents in the membrane-forming water-reducing formulation. For environmental reasons, it is not desirable to include the coalescing solvent in the formulation. However, small amounts (0 to about 50 g / l) of coalescing solvents may be included. When using a coalescing solvent, it is preferable that it is at least water-miscible, and it is still more preferable that it is water-soluble. Among various coalescing solvents, ester-alcohols, such as 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, are generally preferred.

Pigments, plasticizers and optionally coalescing solvents may be mixed directly with the resin in a water emulsion or latex. In this operation, the composite is automatically in the water-reduced form upon full use of ammonia.

Paint formulations can be prepared using the latex of the present invention. Such paint formulations consist of one or more pigments and latexes (water, emulsifiers and resins). Such paints may optionally contain fillers, plasticizers, stabilizers, defoamers, desiccants, fungicides, insecticides, antifouling agents and preservatives.

Pigments are typically added to paint formulations to color the paint and impart hiding power. Titanium dioxide is an example of a widely used pigment that imparts hiding power and whiteness. Representative examples of other widely used pigments include mineral pigments such as oxides of iron and chromium, organic pigments such as phthalocyanine, and active anticorrosive pigments such as zinc phosphate.

Fillers are common inexpensive materials added to paint formulations to achieve the desired concentration and non-settling properties. Fillers may also improve the properties of the paint, such as resistance to degradation and polishing. Representative examples of widely used fillers include chalk, clay, mica, barite and talc, and silica.

Desiccants are chemical compounds that promote drying such as cobalt, lead, manganese, barium and zinc salts. Stabilizers are chemicals that neutralize the damaging effects of heat and ultraviolet radiation. Fungicides and pesticides are commonly added to indoor and outdoor paints. Antifouling compounds are typically added to seawater paints to inhibit seaside growth. Plasticizers are drugs that control the hardness of the membrane or impart flexibility.

Among the various plasticizers, it is preferable to select a liquid having a high enough boiling point, preferably 100 ° C. or higher, even more preferably 150 ° C. or higher, at room temperature such as 25 ° C. to prevent volatilization from the coating composition upon application to a substrate. . Use of plasticizers containing multiple hydroxyl groups may be unstable and should be avoided. The plasticizer enhances the water insolubility of the dried paint of the coalescent resin. In addition, the plasticizer or the plasticizer mixture is characterized by being compatible with the resin itself. Because of this feature, solubility parameters of about 8 to about 16 are required. Such solubility parameters are described in The Encyclopedia of Polymer Science and Technology, Vol. 3, P. 854, 1965, John Wiley and Sons, Inc., and is simply determined by the following equation:

[Equation 1]

δ = (ΣF) / V = F / MW / d

Where

δ is the solubility parameter;

F is Small, P A [J. Appl. Chem. 3, 71, 1953 is the sum of the appropriate molar aspiration constants of the groups determined by;

V is the molar volume at 25 ° C .;

MW is the molecular weight;

d is the density at 25 ° C.

Various plasticizers can be used for this purpose. For example, they may be of the type listed on the Union Series Unit 22 (named plasticizer, issued April 1974) for paint technology as long as it meets melting, boiling and compatibility requirements. Representative examples of preferred plasticizers include butyl benzyl phthalate, a combination of diethylene glycol dibenzoate and dipropylene glycol dibenzoate, and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate.

Representative examples of the various plasticizers include N-cyclohexyl-p-toluene sulfonamide, dibenzyl sebacate, diethylene glycol dibenzoate, di-t-octylphenyl ether, dipropane diol dibenzoate, N-ethyl-p- Toluene sulfonamide, isopropylidenediphenoxypropanol, alkylated naphthalene, polyethylene glycol dibenzoate, op-toluene sulfonamide, trimethylpentanediol dibenzoate and trimethylpentanediol monoisobutyrate monobenzoate as well as phosphate esters, phthalic acid Cyclic plasticizers such as anhydride esters and trimellitic acid esters.

Representative examples of various acyclic plasticizers include adipic acid esters, azelaic acid esters, citric acid esters, acetylcitric acid esters, myristic acid esters, phosphate esters, ricinolic acid esters, acetylrisinolic acid esters, sebacic acid esters, stearic acid esters, and epoxy resins. Esters, and 1,4-butane diol dicaprylate, butoxyethyl pelaronate di [(butoxyethoxy) ethoxy] methane, dibutyl tartrate, diethylene glycol dipelanonate, diisooctyl di Glycolate, Isodecyl Nonanoate, Tetraethylene Glycol Di (2-Ethylbutyrate), Triethylene Glycol Di (2-Ethyl-hexanoate), Triethylene Glycol Diphenylonate and 2,2,4-Trimethyl-1 , 3-pentane diol diisobutyrate.

Additional various cyclic, acyclic and other plasticizers include chlorinated paraffins, hydrogenated terphenyls, substituted phenols, propylene glycols, polypropylene glycol esters, polyethylene glycol esters, melamines, epoxidized soy, oils, melamines, liquid hydrogenation Abietate esters, epoxyphthalate esters, alkyl phthalyl alkyl glycolates, sulfonamides, sebacate esters, aromatic epoxies, aliphatic epoxies, liquid poly (alpha-methyl styrene), maleate esters, meltate esters, benzoates , Benzyl esters, tartrates, succinates, isophthalates, orthophthalates, butyrates, fumarates, glutarates, dicaprylates, dibenzoates and dibenzyl esters. Monoolefins having 4 to 6 carbon atoms, mixtures of monoolefins and diolefins having 4 to 6 carbon atoms, and relatively low molecular weight polymers and copolymers derived from styrene and / or alpha-methyl styrene and the above hydrocarbons and hydrocarbon mixtures may be used. It can be seen that there is.

Preferred esters include carboxylic acids and dicarboxylic acids including fatty acids such as phthalic acid, benzoic acid, dibenzoic acid, adipic acid, sebacic acid, stearic acid, maleic acid, tartaric acid, succinic acid, butyric acid, fumaric acid and glutaric acid having from about 7 to 13 carbon atoms. Prepared by reacting with hydrocarbon diols, preferably saturated hydrocarbon diols.

Representative examples of various phosphate esters include cresyl diphenyl phosphate, tricresyl phosphate, dibutyl phenyl phosphate, diphenyl octyl phosphate, methyl diphenyl phosphate, tributyl phosphate, triphenyl phosphate, tri (2-butoxyethyl) Phosphate, tri (2-chloroethyl) phosphate, tri (2-chloropropyl) phosphate and trioctyl phosphate.

Representative examples of various phthalic anhydride esters include butyl octyl phthalate, butyl 2-ethylhexyl phthalate, butyl n-octyl phthalate, dibutyl phthalate, diethyl phthalate, diisodecyl phthalate, dimethyl phthalate dioctyl phthalate, di (2-ethyl Hexyl) phthalate, diisooctyl phthalate, di-tridecyl phthalate, n-hexyl n-decyl phthalate, n-octyl n-decyl phthalate, alkyl benzyl phthalate, bis (4-methyl-1,2-pentyl) phthalate, butyl Benzyl phthalate, butyl cyclohexyl phthalate, di (2-butoxyethyl) phthalate, dicyclohexyl isodecyl phthalate, dicyclohexyl phthalate, diethyl isophthalate, di n-heptyl phthalate, dihexyl phthalate, diisononyl phthalate, Di (2-methoxyethyl) phthalate, dimethyl isophthalate, dinonyl phthalate, dioctyl phthalate , Dicapryl phthalate, di (2-ethylhexyl) isophthalate, mixed dioctyl phthalate, diphenyl phthalate, 2- (ethylhexyl) isobutyl phthalate, butyl phthalyl butyl glycolate, ethyl (and methyl) phthalyl Ethyl glycolate, polypropylene glycol bis (amyl) phthalate, hexyl isodecyl phthalate, isodecyl tridecyl phthalate and isooctyl isodecyl phthalate.

Representative examples of trimellitic acid esters include triisooctyl trimellitate, tri-n-octyl n-decyl trimellitate, trioctyl trimellitate, tri (2-ethylhexyl) trimellitate, tri-n-hexyl n-decyl trimellitate, tri-n-hexyl trimellitate, triisodecyl trimellitate and triisononyl trimellitate.

Representative examples of various adipic acid esters include di [2- (2-butoxyethoxy) ethyl] adipate, di (2-ethylhexyl) adipate, diisodecyl adipate, and dioctyl adipate (diisoocta Yl adipate), n-hexyl n-decyl adipate, n-octyl n-decyl adipate and di-n-heptyl adipate.

Representative examples of sebacic acid esters include dibutyl sebacate, di (2-ethylhexyl) sebacate, dibutoxyethyl sebacate, diisooctyl sebacate and diisopropyl sebacate.

Representative examples of azelaic acid esters include di (2-ethylhexyl) acelate dicyclohexyl acelate, diisobutyl azelate and diisooctyl azelate. In the practice of the present invention, when using water-reducing compositions of resins, plasticizers and coalescing solvents, the carboxyl groups of the resins are water-reduced by neutralizing with ammonia and mixing with water. The resulting dispersion or solution is generally able to have stable characteristics at about 25 ° C. for at least 30 days, preferably at least 365 days, with little precipitation of the resin.

Generally, for the purposes of the present invention, from about 100 to about 400 parts by weight of water can be used per 100 parts by weight of the neutralized resin, but typically it is required whether a high or low viscosity dispersion or solution is required or a high or low content of Some water may be used depending on whether or not solids are required. It also depends on the coalescing solvent used (if used) and the type and amount of plasticizer. The water-reduced paint composition as an aqueous dispersion or solution is applied as a paint onto suitable substrates such as wood, brick, various plastics and various metals. Water, ammonia and coalescing solvents are typically evaporated from the paint at temperatures ranging from about 20 to about 100 ° C., preferably from about 25 to about 50 ° C., leaving a substantially water insoluble paint of the coalesced resins and plasticizers. In general, such paints can be prepared and applied without the need for additional curing agents to reduce sensitivity.

Thus, an important feature of the present invention is that the crosslinked durable paints are suitable for the preparation of certain resins having balanced hydrophilic and hydrophobic elements and preferably further balanced hard and soft segments, and combinations of pigments and compatible plasticizers. Is formed on a substrate through the formation of a water-reducible paint of such a resin. Crosslinking occurs rapidly at ambient temperature without the need to add a separate hardener or crosslinker. In addition, improved adhesion to metal and glass substrates is also obtained.

The invention is illustrated by the following examples which are not intended to merely exemplify the objects of the invention and to limit the scope or manner of the invention. Unless specified otherwise, parts and percentages are by weight.

Example 1

In this experiment, latex was prepared in a 3 L reactor using the technique of the present invention. The reactor used in this experiment was a butch reactor equipped with an axial flow turbine type stirrer that was used continuously during the polymerization process. Buffer and two monomer solutions were prepared and used for polymerization. The buffer was prepared by mixing 1404 g of water with 68 g of a 39% aqueous solution of sodium alpha-olefin sulfonate surfactant, 2.4 g of sodium acid pyrophosphate (electrolyte) and 3.6 g of ammonium persulfate (initiator).

The sodium alpha-olefin sulfonate soap used was of formula (4):

[Formula 4]

The first monomer solution was prepared by mixing 780 g of styrene, 1.2 g of dodecyl mercaptan, 348 g of n-butyl acrylate, 24 g of acrylic acid and 12 g of methacrylic acid.

After the reactor was evacuated for 30 minutes, the buffer was charged to the reactor. Subsequently, 15% of the first monomer solution was charged to the reactor. The reactor was heated to 135 ° F. (57 ° C.) and polymerized for 45 minutes. Subsequently, 36 g of gamma-methacryloxypropyltrimethoxysilane was added to the remaining monomer solution to prepare a second monomer solution. The second monomer solution was then slowly added over 3 hours and warmed to 165 ° F. (74 ° C.). After the monomer solution was all added, a solution containing 25 g of a 28% aqueous solution of 28% ammonia in 100 ml of water was added and the temperature was maintained at 165 ° F. (74 ° C.). The pH of the latex was adjusted to 8.5 by the final latex with about 41% solids.

Latexes do not contain volatile organic compounds and exhibit a combination of excellent properties used to prepare self-crosslinkable paint formulations such as paints. In fact, the paints produced by these paint formulations exhibited good solvent resistance because they are self-crosslinking. Such paint formulations are particularly useful when used in metals, wood and concrete.

A transparent water-reducible paint formulation was prepared using the latex synthesized in this experiment. This is 0.6 phr of ammonium hydroxide (100 parts per resin), 6 phr of Texanol ^™ ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate) and Kodaflex.

4 phr of a TXIB plasticizer (2,2,4-trimethyl-1,3-pentanediol diisobutyrate) was performed by mixing into a latex. Paints prepared using this paint formulation have proven to have excellent properties for paint substrates, including excellent solvent resistance. In addition, the applied paint was dried in 5 to 7 minutes.

The prepared clear coating formulation was applied to a concrete block dried at room temperature for 4 hours. Paint is Skydrol applied to the surface for 10 minutes.

Not soluble in phosphate esters. The coated concrete surface was also rubbed 100 times with a fabric immersed in methyl ethyl ketone (MEK). The paint on the concrete block remained intact even after rubbing with the fabric soaked in MEK. The results of the rigorous test suggest that the paint has excellent solvent resistance after drying for only 4 hours.

Example 2

In this experiment, the latex synthesized in Example 1 was used to prepare water-reducing self-crosslinking gray paint. This is 14.2 phr of water, 0.86 phr of ammonium hydroxide, texanol ^TM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate) 8.6 phr ^, codaplex ^, TXIB plasticizer (2,2,4- Trimethyl-1,3-pentanediol diisobutyrate) 5.7 phr, Dispersayd.

181 Dispersant 1.4 phr, Titanium Dioxide 22.9 phr, Nytal^TM22.9 phr of the 300 polisher (barium sulfate) and 1.4 phr of carbon black (No. 4) were carried out by high speed mixing into the latex. In the subsequent relaxation phase, 17.1 phr of water, 0.86 phr of hydroxyethyl cellulose and 0.29 phr of Drew L475 defoamer were added under fast mixing conditions.

Paints prepared using this gray paint formulation have proven to have excellent properties for paint substrates, including excellent solvent resistance. In addition, the applied paint was dried in 5 to 7 minutes.

The prepared gray paint formulation was applied to a concrete block dried at room temperature for 4 hours. The paint did not dissolve in skydrol ^or phosphate ester applied to the surface for 10 minutes. In addition, the painted concrete surface was rubbed 100 times with a fabric immersed in MEK. The gray paint on the concrete block remained intact after rubbing with the fabric soaked in MEK. The results of the rigorous test suggest that the paint has excellent solvent resistance after drying for only 4 hours.

Example 3

In this experiment, the latex synthesized in Example 1 was used to prepare a water-reducing self-crosslinking white paint. This is 14.2 phr of water, 0.86 phr of ammonium hydroxide, texanol ^TM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate) 8.6 phr ^, codaplex ^, TXIB plasticizer (2,2,4- 5.7 phr of trimethyl-1,3-pentanediol diisobutyrate) ^, disperside, 1.4 phr of 181 dispersant, 22.9 phr of titanium dioxide and 22.9 phr of Nital ^™ 300 polish remover (barium sulfate) were carried out by high speed mixing. In the subsequent relaxation phase, 17.1 phr of water, 0.86 phr of hydroxyethyl cellulose and 0.29 phr of Dru L475 defoamer were added under fast mixing conditions.

Paints made using this white paint formulation have proven to have excellent characteristics for paint substrates, including excellent solvent resistance. In addition, the applied paint was dried in 5 to 7 minutes.

The prepared white paint formulation was applied to a concrete block dried at room temperature for 4 hours. The paint did not dissolve in skydrol ^or phosphate ester applied to the surface for 10 minutes. In addition, the painted concrete surface was rubbed 100 times with a fabric immersed in MEK. White paint on the concrete block remained intact even after rubbing with a fabric immersed in MEK. The results of the rigorous test suggest that the paint has excellent solvent resistance after drying for only 4 hours.

Example 4

In this experiment, the latex synthesized in Example 1 was used to prepare a water-reducing self-crosslinking black paint. This is 14.2 phr of water, 0.86 phr of ammonium hydroxide, texanol ^TM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate) 8.6 phr ^, codaplex ^, TXIB plasticizer (2,2,4- Trimethyl-1,3-pentanediol diisobutyrate) 5.7 phr, disperside ^, 181 dispersant 1.4 phr, silica 22.9 phr, nital ^TM 300 polish remover (barium sulfate) 22.9 phr and carbon black (No. 4) 1.4 phr This was done by high speed mixing in latex. In the subsequent relaxation phase, 17.1 phr of water, 0.86 phr of hydroxyethyl cellulose and 0.29 phr of Dru L475 defoamer were added under fast mixing conditions.

Paints prepared using this black paint formulation have proven to have excellent properties for paint substrates, including excellent solvent resistance. In addition, the applied paint was dried in 5 to 7 minutes.

The prepared black paint formulation was applied to a concrete block dried at room temperature for 4 hours. The paint did not dissolve in skydrol ^or phosphate ester applied to the surface for 10 minutes. In addition, the painted concrete surface was rubbed 100 times with a fabric immersed in MEK. The black paint on the concrete block remained intact after rubbing with the fabric soaked in MEK. The results of the rigorous test suggest that the paint has excellent solvent resistance after drying for only 4 hours.

Paint formulations made using the latex of the present invention have been demonstrated to provide good shear stability. In addition, the paint formulation has proven to be excellent in can stability. Latex with smaller particle size has been demonstrated to crosslink faster than latex with large particle size. Thus, such latexes preferably have a particle size of about 90 to about 120 nm.

Example 5 (Comparative)

In this experiment, latex was prepared in a reactor using the emulsifier system described in US Pat. No. 4,968,741 and US Pat. No. 5,122,566. The reactor used for this experiment was equipped with a regulator for stirring and operated at about 200 rpm (rpm). Buffers, initiator solutions and monomer solutions were prepared and used for polymerization. The buffer was prepared by mixing 15.6 kg of water with 340 g of alkyl phosphate ester sodium salt and 340 g of dodecanol at pH about 3. An initiator solution was prepared by mixing 1.36 kg of water and 68 g of ammonium persulfate. The monomer solution was prepared by mixing 8.85 kg of styrene, 27 g of t-dodecyl mercaptan, 3.95 kg of n-butylacrylate, 272 g of acrylic acid, 136 g of methacrylic acid and 408 g of gamma-methacryloxypropyltrimethoxysilane. It was.

After the reactor was evacuated for 30 minutes, the buffer was charged to the reactor. Then 20% of the monomer solution was charged to the reactor. The reactor was heated to 165 ° F. (74 ° C.) and half of the initiator solution was added to the reactor. After polymerization for about 30 minutes, the remaining amount of the multimer solution started to be added continuously. Additional monomer solution was added over about 3 hours at a rate sufficient to maintain about 165 ° F. (74 ° C.) in the reactor. The remaining amount of initiator solution was charged to the reactor about 2 hours after polymerization.

The latex prepared using this process had a solid content of 46.0%, a pH of 1.88, a Brookfield viscosity of 583 centipoise and an amount of flocculation 115 g. The pH of the latex was adjusted to 9.5 by adding ammonium hydroxide.

The latex produced in this experiment was so unstable that it could not be formulated with a clear coating composition or paint. Thus, this experiment suggests the importance of using alpha-olefin sulfonate soaps in latex synthesis.

Modifications are possible in the light of the teachings herein. While certain representative embodiments have been presented to illustrate the invention, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention. Accordingly, it is, of course, possible to vary such specific aspects within the scope of the invention as defined by the appended claims.

Paints formulated using the latex of the present invention not only have good solvent resistance, flexibility and ultraviolet light resistance but also provide environmental benefits.

Claims (3)

(1) water; (2) based on 100% by weight of monomer, (a) about 30 to about 75 weight percent of a vinyl aromatic monomer, (b) about 20 to about 65 weight percent of an alkyl acrylate monomer, (c) about 1 to about 8 weight percent of an alkyl propene acid monomer, and (d) resins having repeating units derived from about 0.5 to about 5 weight percent of an acryloxyalkenyltrialkoxysilane monomer; (3) hydrating agents; And (4) defoamer Water-reducible coating composition consisting of. (1) water; (2) emulsifiers; And (3) (a) about 30 to about 75 weight percent of a vinyl aromatic monomer, (b) about 20 to about 65 weight percent of an alkyl acrylate monomer, (c) about 1 to about 8 weight percent of an alkyl propene acid monomer, and (d) a polymer consisting of repeating units derived from about 0.5 to about 5 weight percent of an acryloxyalkenyltrialkoxysilane monomer A latex used in the manufacture of self-crosslinkable water-reducible paints. The method of claim 1, The repeating unit of the resin is about 40 to about 70 weight percent styrene, about 25 to about 55 weight percent butyl acrylate, about 1.5 to about 5 weight percent acrylic and methacrylic acid monomers, and about 1 acryloxyalkenyltrialkoxysilane monomer From about 3% by weight, wherein the acrylicoxyalkenyltrialkoxysilane monomer is gamma-methacryloxypropyltrimethoxysilane.