This invention concerns compositions that are applied to the surface of construction materials to improve resistance to weather and/or environment caused degradation.

Many different compositions and methods have been used in the field to treat the surface of construction materials. The compositions have included organic-based chemicals such as silanes, siliconates, siloxanes, silicone resins, urethanes, methacrylates, styrene-butadiene copolymers, and inorganic-based chemicals such as sodium and potassium silicates. For organic-based materials, they are either water-based or solvent based or water/solvent-based.

A comprehensive evaluation was conducted on concrete sealers available commercially by the National Cooperative Highway Research Program (NCHRP). NCHRP Report 244 disclosed the test results along with the representative commercial products available in 1981. Among 21 products which the NCHRP program evaluated, four of the products could reduce water absorption by 75%. These four materials were two epoxy- based products, one methacrylate-based product, and one urethane-based product. All other materials based on linseed oil, silane, siloxane, siliconate, chlorinated rubber butadiene, etc., failed to reduce water absorption by 75%. Some of the above organic-based products were highly harmful to the environment and unsafe to the user because they were solvent-based solutions.

Many prior art patents disclosed compositions and/or methods to treat the surface of construction materials and render the material water repellent. U. S. Patent No. 3,772,065 disclosed a composition based on alkyltrialkoxysilane solution with alcohol as solvent. The composition was

U. S. Patent No. 3,772,065 disclosed a composition based on alkyltrialkoxysilane solution with alcohol as solvent. The composition was used for water-proofing on masonry applications. U. S. Patent No. 3,819,400 disclosed a composition based on silane and siloxane solution that can be used for surface protection of porous materials. U. S. Patent No. 3,879,206 disclosed a composition based on alkyltrialkoxysilane solution with alcoholic or benzene type solvent. The composition was used for the impregnation of masonry surfaces. U. S. Patent No. 4,341 ,560 disclosed a composition of the combination of alkaline metal alkylsiliconate or phenyl siliconates, calcium hydroxide or calcium oxide, and/or poly-α, β-unsaturated carboxylic acid. The composition was used for waterproofing of gypsum molded products. U. S. Patent No. 4,536,534 disclosed an aqueous primer composition based on an alkali-soluble acrylic resin and siliconates. The composition was used for waterproofing strongly alkaline substrates. U. S. Patent No. 4,814,407 disclosed a composition based on an alkylalkoxysilane or a fluoroalkylalkoxysilane. The composition was used for reducing water absorption of substrates. U. S. Patent No. 4,816,506 disclosed a composition containing aqueous silicone dispersions based on the combination of poly diorganosiloxane, (organo)metallic compound(s), a siliconate, and an optional silicone resin. The composition was used for elastomeric coating or sealant applications. U. S. Patent No. 4,894,405 disclosed a composition based on the combination of a polyurethane and an organosilane. The composition was used for concrete and masonry waterproofing applications. U. S. Patent No. 4,476,282 disclosed a method to produce finely divided, stable oil-in-water emulsions of organo polysiloxanes. U. S. Patent No. 4,517,357 disclosed a composition of silanol solution prepared by hydrolysis of alkyltrialkoxysilanes. U. S. Patent No. 4,648,904 disclosed a composition based on an aqueous silane system. The composition was used for rendering masonry surfaces water repellent. U. S. Patent No. 5,356,716 disclosed a composition based on the

combination of mainly polyurethane, siliconate, and silicate. The composition was used for waterproofing concrete, masonry, and porous surfaces.

All of these prior art compositions are based on formation of a hydrophobic film on the substrates where they are applied. The compositions may provide adequate waterproofing to the substrates for a short period of time, but, the compositions tend to deteriorate over time when exposed to environments such as ultraviolet radiation. They are also easily worn away when the substrates are subjected to frequent abrasion such as occurs in parking garages and on highway pavement. Therefore, an "offensive" approach is needed to provide adequate waterproofing to the substrates to extend service life of the waterproofing and to reduce the possibility of substrate wearing. Such an approach can be enabled by the compositions which have water repellency function, are chemically reactive to form strong bonding with the substrate, are capable of penetrating into substrate to form multilevel waterproofing layers, and can enhance the hardness of the substrate to resist abrasion. The present invention is an example of this offensive approach.

The present invention concerns novel compositions which can be used to treat the surface of construction materials. The treatment can prevent the construction materials from deterioration associated with physical, chemical, and biological processes which in turn are associated with the penetration of moisture into the structures made with these materials. The products in this invention can also be used to prevent the treated construction materials from deterioration associated with solvent attack, such as gasoline and motor oil, etc.

The term "construction materials" as used herein is intended to include concrete materials; wooden materials; natural and artificial stones, plastic, metal, plaster, ceramic materials such as bricks, masonry, tile,

concrete aggregates which are subject to alkali-silica reactions etc.; and other materials with the potential of damage due to water absorption.

The term "concrete materials" as used herein is intended to include the systems containing cementitious materials, water, aggregates, and ASTM C494 defined chemical admixtures such as water reducing, set accelerating and retarding admixtures, and other chemical admixtures added to concrete for various purposes such as corrosion control, shrinkage control, etc. Such systems can be concrete, grout, mortar, and products made therefrom. The term "cemetitious materials" as used herein includes the systems which harden after being mixed with water. Such systems include portland cements such as described in ASTM C150, white portland cements, calcium aluminate cements, etc. Such systems also include the above mentioned cements blended with ASTM C311 defined pozzolanic materials such as fly ash, raw or calcined natural pozzolans, ASTM C989 defined ground granulated blast furnace slag, ASTM C-1240 defined silica fume materials.

The term "structures" as used herein is intended to include the elements made with previously mentioned material and/or materials. Such structures include highways, bridges, parking garages, stadiums, airport runways, sidewalk ways, buildings, landmark architectures, historic structures, sewer pipes, and lining tile, and any other elements need to be protected from moisture/water intake.

The structures made with concrete, wooden, natural stone, plaster, and fibrous ceramic materials have a tendency to absorb water from the environment. The water absorption into these materials can induce damage to the materials by physical, chemical, and biological processes. The processes can be aggravated by the presence of harmful chemicals in the water and surrounding environment.

For example, in the case of concrete structures, water can be transported into and out of the concrete matrix through the continuous capillary pores in the concrete. This mass exchange process of water with concrete will adversely affect the performance of concrete; for example: 1. Chemical deterioration: Water in the environment always contains harmful chemicals such as sulfate, chloride, sodium and potassium, etc. When these chemicals penetrate into concrete accompanying with water, several destructive reactions will take place in concrete and will result in damage to concrete. Typical examples are as follows: (1) sulfate attack;

(2) corrosion;

(3) alkali-silicate aggregate;

(4) leaching and

(5) efflorescence. 2. Physical destruction: When water is subjected to temperature cycles causing freezing and thawing, its volume expands when it freezes. When the water present in the concrete is confined in the pores of the concrete, the volume expansion will exert a force to its surrounding area of concrete. If the stress generated by this force is greater than the strength of the concrete, the concrete will disrupt and cause scaling on the surface and cracking through the body of the concrete.

It is obvious that in order to reduce the potential damage to construction materials due to water absorption, it is important to prevent water/moisture from penetrating into these materials. Water repellency chemicals/products are frequently used to treat or coat the surface of the construction materials to render them repellent to liquid water.

The present invention provides compositions comprising quaternary systems which contain water, organofunctional silanes (referred to silane

thereafter), alkali metal organosiliconates (referred to as siliconate hereinafter), and water soluble alkali metals polysilicates (referred to hereinafter as silicate ).

Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood to be modified in all instances by the term "about".

The water used in the formulation of the compositions of this invention can be from tap water supplies for general public users. The organofunctional silanes used in the practice of this invention should be water soluble and remain stable in the pH range of 7-11 , depending on the water percentage in the formula. The silane used in the inventive compositions may be polymerized, for example to form a dimer or a trimer, as long as the polymerized silanes do not precipitate and separate from the solution. Such silanes include, but are not limited to: vinyl-tris-(2- methoxyethoxy)silane, γ-amino-propyltriethoxysilane, γ- aminopropyltrimethoxysiiane, N-β-aminoethyl-γ-aminopropyl- trimethoxysilane, triaminofunctionalsilanes, N-β-aminoethyl-β- aminopropylmethyldimethoxysilane, β-amino-γ-methylethyltriethoxysilane, γ- aminopropyltriethoxysilane, γ-aminobutyltrimethoxysilane, ω- aminohexyltriethoxy-silaπe, γ-aminopropylmethyldiethoxysilane, γ- aminopropylphenyldiethoxysilane N-methyl-γ-aminopropyltriethoxysilane, N.N-dimethyl-γ-aminopropyltriethoxysilane N-γ-aminopropyl-γ- aminobutyltriethoxysilane, aminomethyltrimethoxysilane, β- aminoethyltrimethoxysilane, β-aminoethyltriethoxysilane,γ- aminobutyltriethoxysilane β-methylaminoethyltriethoxysilane, β- ethylaminoethyltriethoxysilane, γ-methylamino-propyltrimethoxysilane, γ- propylaminopropyltriethoxysilane, γ-ethylaminobutyltriethoxy-silane, γ- phenylaminopropyltrimethoxysilane and γ-phenylaminopropyltriethoxysilane.

All of the above silanes can be hydrolyzed to produce their corresponding silanols and/or siloxanes. The corresponding silanols and/or siloxanes can also be employed in this invention. A typical example is γ- aminopropyltriethoxysilane which can be hydrolyzed to corresponding silanols and/or siloxanes. A commercial example of a hydrolyzed γ- aminopropyltriethoxysilane is Siquest 1106™.

The alkali metal organosiliconates used in the invention can be sodium methyl siliconate and/or potassium methyl siliconate and/or mixtures thereof. The alkali polysilicates used in the invention are selected from sodium silicate, potassium silicate, lithium polysilicate, and mixtures thereof, or the combination of these three. The ratio range of SiO ₂ : M ₂ 0 (M = Na, K, and Li) is preferred to be between 2~10.

The proportion of each component, other than water, useful in practicing this invention is included in the blackened area of the following ternary phase diagram:

0.8 0.6 0.4 0.2 0 Silicate

The percentage of water is between about 60 and about 95%, by weight, and the percentage of active chemicals (combination of silane, siliconate and silicate) is between about 5 and about 40%. The chemical components of the compositions in the ternary mixtures of the phase diagram include compositions containing about 0.1 to 0.6 parts of an alkali metal siliconate, 0.1 to 0.5 parts of an organofunctional silane and 0.2 to 0.8 parts of a water soluble alkali polysilicate.

The proportion of each chemical component is more accurately expressed in the ternary phase diagram of the Figure. Compositions that are contained inside the darkened region of the Figure are useful compositions of this invention. The proportion outside the darkened region will not yield either a stable or an effective product.

The procedure of manufacturing is critical to obtain a stable and an effective composition. General procedure for high percentage of active component (higher than 20%) is as follows:

1. Add silane into water while stirring at the rate between 500 and about 1500 rpm, and let the silane hydrolyze for at least 6 hours, preferably overnight, before adding another ingredient.

2. Add alkali organosiliconate slowly into silane solution while stirring. Optionally step one can be avoided by adding the alkali organosilicate to a hydrolyzed silane. 3. Add above prepared solution slowly into alkali polysilicate solution while stirring.

General procedure for low percentage of active component (less than 20%) is as follows:

1. Add the silane into water while stirring at the rate between 500 and about 1500 rpm, and let silane hydrolyze for at least 6 hours, preferably overnight, before adding other ingredients.

2. Add alkali organosiliconate slowly into the silane solution while stirring. Optionally step one can be avoided by adding the alkali organosiliconate to a hydrolyzed silane. 3. Add alkali polysilicate into above solution while stirring.

The following examples prepared using the foregoing procedures, further illustrate the invention and are not intended as limiting.

Example 1:

Table 1 Formulation of Example 1

Raw Material Supplier % Active Component Batch Wt (g)

Tap Water Any City 75.71 76.7

Dow Corning Z-6020™ Dow Corning 7.29 23.0

Dow Corning 777™ Dow Corning 7 44.5

Lifetech 705™ FMC, Lithium Division 10 113 0

Table 2 Performance of Example 1

Substrate Surface treatment Performance Control Example 1

Porous sandpaper abraded Water Absorption at 21 Days 7 3 1 7 Concrete Water Reduction at 21 Days — 76 8

Dense sandpaper abraded Water Absorption at 21 Days 3.3 0.7 Concrete Water Reduction at 21 Days — 80 1

Dense sand blasted Water Absorption at 21 Days 4.04 0 78 Concrete Water Reduction at 21 Days — 80 8

Abrasion saw cut Weight Loss (g) 2 80 1.70

Wear Index 187 113

Example 2:

Table 3 Formulation of Example 2

Raw Material Supplier % Active Component Batch Wt. (g)

Tap Water Any City 84 4 145

Dow Corning® Z-6020™ Dow Corning 3.6 11.3

Dow Corning® 777™ Dow Corning 7 42 5

Lifetech 705™ FMC, Lithium Division 5 56 5

Table 4: Performance of Example 2

Substrate Surface treatment Performance Control Example 2

Dense sandpaper abraded Water Absorption at 21 Days 3.3 1.0 Concrete Water Reduction at 21 Days — 69.8

Dense sand blasted Water Absorption at 21 Days 4.04 0.83 Concrete Water Reduction at 21 Days — 79.4

Example 3:

Table 5: Formulation of Example 3

Raw Material Supplier % Active Component Batch Wt. (g)

Tap Water Any City 81.2 94

Dow Corning® Z-6020™ Dow Corning 1.8 5.67

Dow Corning® 777™ Dow Corning 7 42.5

Lifetech 705™ FMC, Lithium Division 10 113

Table 6: Performance of Example 3

Substrate Surface treatment Performance Control Example 3

Dense sandpaper abraded Water Absorption at 21 Days 3.3 1.1 Concrete Water Reduction at 21 Days — 67.5

Dense sand blasted Water Absorption at 21 Days 4.04 0.98 Concrete Water Reduction at 21 Days — 75.7

Example 4:

Table 7: Formulation of Example 4

Raw Material Supplier % Active Component Batch Wt. (g)

Tap Water Any City 83.4 113

Dow Corning® Z-6020™ Dow Corning 3.6 11.3

Dow Corning® 777™ Dow Corning 3 18.2

Lifetech 705™ FMC, Lithium Division 10 113

Table 8: Performance of Example 4

Substrate Surface treatment Performance Control Example4

Dense sandpaper abraded Water Absorption at 21 Days 3.3 0.9 Concrete Water Reduction at 21 Days — 72.2

Dense sand blasted Water Absorption at 21 Days 4.04 0.80 Concrete Water Reduction at 21 Days — 80.2

Example 5:

Table 9: Formulation of Example 5

Raw Material Supplier % Active Component Batch Wt. (g)

Tap Water Any City 72.6 37.5

Dow Corning® Z-6020™ Dow Corning 1.8 5.67

Dow Corning® 777™ Dow Corning 7 42.5

Lifetech 705™ FMC, Lithium Division 15 170

Table 10. Performance of Example 5

Substrate Surface treatment Performance Control Example 5

Dense sandpaper abraded Water Absorption at 21 Days 3.3 1.2 Concrete Water Reduction at 21 Days — 63.1

Dense sand blasted Water Absorption at 21 Days 4.04 0.78 Concrete Water Reduction at 21 Days — 80.7

Example 6:

Table 11 : Formulation of Example 6

Raw Material Supplier % Active Component Batch Wt (g)

Tap Water Any City 74.4 31.8

Dow Corning® Z-6020™ Dow Corning 3.6 11.3

Dow Corning® 777™ Dow Corning 7 42.5

Lifetech 705™ FMC, Lithium Division 15 170

Table 12: Performance of Example 6

Substrate Surface treatment Performance Control Example 6

Dense sandpaper abraded Water Absorption at 21 Days 3.3 0.9 Concrete Water Reduction at 21 Days — 73.6

Dense sand blasted Water Absorption at 21 Days 4.04 0.78 Concrete Water Reduction at 21 Days — 80.8

In the foregoing examples Dow Corning Z-6020 ,TM is identified as aminoethyl-aminopropyldimethoxxsilane, Dow Corning777™ as potassium methylsiliconate and Lifetech 705 TM as lithium polysilicate