WO2000058091A1

WO2000058091A1 - Cementitious veneer

Info

Publication number: WO2000058091A1
Application number: PCT/US1999/006934
Authority: WO
Inventors: Chris Wallner
Original assignee: Chris Wallner
Priority date: 1999-03-29
Filing date: 1999-03-29
Publication date: 2000-10-05
Also published as: AU3216599A

Abstract

The veneer composition and method for applying said veneer composition are provided. The veneer includes at least a base layer (20) made from a mixture including acrylic polymer latex, aggregate and water, and at least a second ornamental layer (30) made from a mixture including cement, gypsum, acrylic resin, water and optionally pigment. The compositions are applied to a surface (10) by means including spraying and manual spreading. The second layer (30) can be ornamentally manipulated either prior or subsequent to curing. The veneer can be provided as a kit including the substances used to form the base (20) and ornamental (30) layers.

Description

CEMENTITIOUS VENEER

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to decorative surface coatings and, more particularly, to durable surface coatings which incorporate cement.

2. Description of Related Art

Stone, cement and brick objects have long been valued for both their structural integrity and aesthetic appearance. Since stone, cement and brick are relatively heavy, special measures may be necessary to insure that objects and structures made of such materials are properly supported. Unfortunately, not all existing buildings or other structures are capable of bearing the weight of such objects. Indeed, costly reinforced frames, reinforced flooring, etc. are frequently required to insure such support. In certain cases, the cost of proper support is prohibitive.

In addition, the cost of stone, cement and/or brick (hereinafter collectively referred to as "masonry") can also be expensive. Consequently, economical lighter weight surface coatings which simulate the appearance of masonry have been used to enhance the appearance of both utilitarian and decorative objects.

Fig. 1 is a perspective view of an uncoated surface 10 according to the prior art. It is well known in the prior art to apply a surface coating or covering to such surface, for both structural and aesthetic purposes. Examples of common surface coatings which have been made to simulate the appearance of masonry include vinyl wall coverings, fabrics, paints and plaster. Unfortunately, these materials have certain shortcomings. Vinyl wall coverings usually provide a rubbery appearance and are typically recognizable as imitations. Fabrics and paint may be printed or applied in such manner to give a superficial appearance of masonry but since these materials are so different as compared to masonry, they are also easily detectable as imitations. Moreover, fabrics and paint are relatively delicate and do not withstand a great deal of wear and tear. Plaster may give a better approximation of masonry than the above materials, but plaster is relatively soft and lacks durability which is typically manifest by chipping and cracking.

The search for lightweight durable materials which give the appearance of masonry has lead to masonry-like coatings which may be applied to suitable foundation materials such as wood, metal or polymeric objects. For example, a method and apparatus for producing an ornamental concrete surface is described in U.S. Patent No. 5,502,941.

As described therein, an ornamental coating which appears as brick or flagstone may consist of a waterproof sub-base of epoxy resin and an elastomeric sealant covered with fiberglass webbing. A first mortar layer of cement, sand, color pigment and aqueous solution of adhesive resin is then sprayed or troweled on. When the first layer cures, a template having a pattern of grout lines is placed over the first layer and a second mortar layer having the same composition as the first layer is applied except that a contrasting color is used to give the appearance of grouted brick or flagstones. The ratio of cement to sand is given as 50-50% with solution of acrylic resin varying from 11 2 to 2 gallons per 46 lb. bag of dry cement/sand mix.

U.S. Patent No. 5,447,752 describes a method for making a decorative cementitious pattern on a surface. The surface coating composition is described as comprising cement, sand, a polymer binder and water. The binder is an acrylic latex polymer such as styrene butadiene in water. Cement is mixed with sand (30-40% cement) to form a mixture which is combined with the binder solution in an amount ranging from 2-3 gallons binder solution to 100 pounds cement/sand. The preexisting surface is etched with muriatic acid, brushed and spray washed. A template having a desired pattern is placed on the surface and a layer of the surface coating composition is applied into openings in the template by spraying or by manual spreading.

U.S. Patent No. 3,592,724 describes a cementitious laminate of sulfonated polymers useful for making walls, floors, ceilings and plasterboards having improved water vapor impermeability. As described therein, the laminates consist essentially of a surface sulfonated water insoluble resinous film and an inorganic cementitious material adhering to at least one surface of the film. In one aspect, hydraulic cement is plastered on a wall and sulfonated film is adhered to the plastered wall. The laminated wall may be finished with a coat of gypsum plaster.

There is a continuing need for economical lightweight and durable coatings which can be used to simulate the appearance and function of masonry. The present invention resulted from the search to fill that need.

SUMMARY OF THE INVENTION

A veneer composition is provided which includes at least one base layer including acrylic polymer latex, aggregate, and water and at least one ornamental layer including cement, gypsum, acrylic resin and water. A method of forming a veneer is also provided which includes providing a first mixture including acrylic polymer latex, aggregate and water; applying the first mixture to an underlying surface; allowing the first mixture to at least partially cure; providing a second mixture including cement, gypsum, acrylic resin and water; applying the second mixture over the first at least partially cured mixture: and allowing the second mixture to at least partially cure. Also provided is a kit for forming a veneer which includes a first mixture which includes acrylic polymer latex, aggregate and water and a second mixture which includes cement, gypsum, acrylic resin and water.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of an uncoated surface according to the prior art; Fig. 2 is a perspective view of a surface coated with a first base layer of a cementitious veneer according to the invention; and

Fig. 3 is a perspective view of a decorative cementitious veneer according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a cementitious, masonry-like veneer surface that is economical, lightweight, highly durable and easily applied to a variety of surfaces. The invention can be readily provided in a variety of colors and textures. In addition, the invention can also be shaped, sanded and/or polished to achieve a desired appearance.

The invention provides a highly-accurate simulation of the appearance, feel and durability of natural masonry. Furthermore, the invention has sufficient strength to resist chipping, gouging and cracking, but is light enough to cover desired objects without requiring additional support.

The invention can be applied to cover any appropriate underlying surface on which a masonry-like finish is desired. Examples of such surfaces include wood, metal, masonry, fiberglass, gypsum board, Masonite®, plastics and other common building materials. The surface can be of any shape, such as flat or curved.

The underlying surface should be clean and dry. To provide an optimal bonding surface, the underlying surface can be prepared by etching or sanding. Any method of such surface preparation for bonding known to those with skill in the art may be used herein.

A first base layer is then applied to the underlying surface. This first base layer is formed of a composition including acrylic latex, aggregate and water. This composition is readily prepared by one skilled in the art, using well-known techniques. Suitable acrylic latexes for use herein are those which readily polymerize in water. Such acrylic latexes can include acrylic polymers and acrylic monomers, for example alkyl acrylates, methacrylates, lower alkyl acrylates. butadiene and styrene.

Aggregates for use in accordance with the invention are exemplified by a mixture of course and fine relatively inert materials but may also be of fairly uniform size. Aggregates include sand, gravel, silica, glass, crushed stone such as marble, granite, feldspar, basalt, quartz, etc.

In a preferred embodiment of the invention, a substantially homogeneous mixture is prepared by mixing from 10% to about 60% powdered monomer with water and surfactant. Aggregate can be added before or after the monomer is mixed with water. The concentration of aggregate can vary from about 10% to about 75% of the total mixture. Concentration percentages provided herein are by volume, unless otherwise specified.

An example of a suitable composition for forming the first layer is known as Primus®, commercially available from Dryvit Systems. Inc. of Rhode Island. Primus® is described by the manufacturer as containing 54-62% sand. 26-28% water and 9.9-10.2% acrylic latex polymer/binder.

Polymerization of such acrylic monomers in water is known as emulsion polymerization. Emulsion polymerization is usually rapid and produces high molecular weight polymers at high concentrations and low viscosity. No dangerous volatile solvents are used in emulsion polymerization. Thus, emulsion polymerization is especially well-suited for use in a variety of settings. Moreover, because emulsion polymerization temperatures are relatively low, heat damage to underlying surfaces is avoided.

Initiator and accelerator are added to the composition to catalyze polymerization and curing. Such polymerization catalyst may be added in amounts ranging from about 0J to about 6% of the mixture. For example, a substance such as water soluble peroxide salts can be added to initiate the polymerization process. The reaction can be accelerated with the addition of reducing agents and/or polyvalent metal salts. It is well-known to use a surfactant in emulsion polymerization. Suitable surfactants include anionic, cationic and/or nonionic surfactants such as salts of alkyl sulfates, alkylarene sulfates, alkyl polyoxyethylenes or aryl polyoxyethylenes. Any technique for emulsion polymerization known to those with skill in the art may be incorporated herein.

Fig. 2 is a perspective view of a surface 10 coated with a first base layer of a cementitious veneer according to the invention. The composition for forming the first layer 20 is mixed together to form a liquid. This liquid can be applied by means including spraying or manual spreading, for example using a brush or trowel.

The viscosity of the mixture is dependent upon the concentration of monomer and aggregate. The viscosity can therefore be adjusted to optimize application to the surface. For example, if application by spraying is desired, a relatively low viscosity mixture is prepared. A more viscous mixture can be prepared for manual spreading.

The mixture is applied to an underlying surface prior to curing and hardening. The mixture is then allowed to cure until hard. Curing time will depend on the amount of resin and initiator/accelerator used. The mixture can be applied in amounts sufficient to form a layer having a thickness of between approximately 1/16 inch and approximately 1/8 inch.

Fig. 3 is a perspective view of a decorative cementitious veneer according to the invention. A second ornamental layer 30 is applied over the first base layer 20. The second layer is made from a mixture of cement such as Portland cement, gypsum, acrylic resin, water and optionally pigment.

In the preferred embodiment of the invention, the ratio of gypsum to cement is 20 to 1. An example of a suitable gypsum/cement mixture is Hydrostone®, commercially available from United States Gypsum Company, Illinois.

The cement/gypsum mixture is then combined with water and acrylic resin in an amount ranging from 19 oz. to 22 oz. cement gypsum to 6.8 to 1.2 oz. water to 0.8 to 1.2 oz. acrylic resin. Pigment such as an oxide powder or paste may be added to impart a desired color to the mixture. Any pigment compatible with cement/ gypsum known to those with skill in the art may be used herein.

The resulting mixture is then applied over the first layer by means such as spraying, brushing or troweling. The thickness of the layer preferably ranges from approximately 1/8 inch to approximately 1/4 inch.

The second layer dries relatively quickly, depending upon thickness, the precise composition of the mixture, and environmental conditions. For example, the second layer can harden within approximately 15 minutes. During the drying period, the surface of the layer may be ornamentally manipulated by means including embossing with a template, pressing, stamping, or carving.

After the outer layer has cured, it can be further finished by polishing by, for example, wet or dry sanding. The invention can be coated on a material which can itself be cut. The invention can be cut along with the underlying material. In such case, the invention does not chip or scratch, and any rough edges can be easily polished if desired.

The material of the outer layer hardens to a strength of approximately 2545 psi within about 24 hours. For example, one embodiment of the invention was experimentally tested to determine hardness, durability, and quality. In this experiment, the invention was subjected to the 3M Corporation (Minneapolis, Minnesota) Granule Embedding Machine Test. This test is considered to be an industry standard for testing roofing tiles for their durability and quality. In this test, also known as the bristle test, a sample is subjected to repeated strokes of an extremely hard wire bristle. The test measures the amount of material removed by the scraping action, as well as the depth of any score marks produced by the bristles.

A sample of the invention was stroked 200 times with a wire bristle. The original weight of the sample was 65.34 grams. After the 200 strokes, the sample weighed 65.16 grams. The surface scoring observed was negligible. It should be understood that the embodiments and examples provided herein are for purposes of illustration of the invention. It is envisioned that those with skill in the art can make modifications to the embodiments and examples provided herein which are within the scope and spirit of the invention.

For example, while the above embodiments and examples encompass a first layer and a second layer, it is contemplated that more than two layers can be applied in accordance with the present invention. Additional layers of the above described base mixture can be stacked upon each other. Likewise, additional ornamental layers can be stacked upon each other. Indeed, base layers and ornamental layers can be stacked upon each other in alternating fashion.

The invention can be provided as a kit that includes the substances required to form the first base layer and second ornamental layer. Such substances can be pre-mixed, or can be supplied for mixing by the user. The kit can also include containers for mixing and storing the layer mixtures, as well as means for applying the layers to a surface, such as a trowel.

Further modifications may be made which are considered to be within the scope of the following claims.

Claims

What is claimed is:

1. A cementitious veneer, comprising: at least a first base layer comprising a mixture of acrylic latex, aggregate and water; and at least a second ornamental layer applied over said at least a first base layer, said second ornamental layer comprising a mixture of cement, gypsum, acrylic resin, and water.

2. The cementitious veneer of Claim 1. wherein said acrylic is selected from the group consisting of acrylic polymers, acrylic monomers, alkyl acrylates, methacrylates. lower alkyl acrylates, butadiene, and styrene.

3. The cementitious veneer of Claim 1, wherein said aggregate is selected from the group consisting of sand, gravel, silica, glass, and crushed stone.

4. The cementitious veneer of Claim 1, further comprising a surfactant added to said first base layer.

5. The cementitious veneer of Claim 4. wherein said surfactant is selected from the group consisting of anionic, cationic and nonionic surfactants, salts of alkyl sulfates, alkylarene sulfates, alkyl polyoxyethylenes, and aryl polyoxyethylenes.

6. The cementitious veneer of Claim 1, further comprising a polymerization catalyst added to said first base layer in a concentration by volume of between approximately 0.1 to approximately 6%.

7. The cementitious veneer of Claim 6, wherein said polymerization catalyst includes an initiator or an accelerator.

8. The cementitious veneer of Claim 7, wherein said initiator is water soluble peroxide.

9. The cementitious veneer of Claim 7. wherein said accelerator is selected from the group consisting of reducing agents and polyvalent metal salts.

10. The cementitious veneer of Claim 1. wherein said first base layer comprises between 10%) to about 60%> by volume of powdered monomer.

11. The cementitious veneer of Claim 1. wherein said first base layer comprises between 10% to about 75%o by volume of aggregate.

12. The cementitious veneer of Claim 1. wherein said first base layer forms a layer having a thickness of between approximately 1/16 inch and approximately 1/8 inch.

13. The cementitious veneer of Claim 1, wherein the ratio of gypsum to cement in said second layer mixture is 20 to 1.

14. The cementitious veneer of Claim 1. wherein said second layer comprises between 19 - 22 oz. cement/gypsum mixture, between 6.8 to 1.2 oz. water, and between 0.8 to 1J oz. acrylic resin.

15. The cementitious veneer of Claim 1 , wherein said second ornamental layer includes pigment.

16. The cementitious veneer of Claim 1 , wherein said second layer has a thickness of between approximately 1/8 inch and approximately 1/4 inch.

17. The cementitious veneer of Claim 1, wherein said second layer is ornamentally manipulated prior to drying.

18. The cementitious veneer of Claim 1, wherein said second layer is further finished after curing.

19. A cementitious veneer for a surface, comprising: at least a first base layer comprising a mixture of between 10% to about 60% by volume of acrylic latex, X0% to about 75% by volume of aggregate, and water; a surfactant added to said first base layer mixture; a polymerization catalyst added to said first base layer mixture, said polymerization catalyst comprising an initiator and an accelerator, said polymerization catalyst in a concentration by volume of between approximately 0J to approximately 6%; and at least a second ornamental layer applied over said at least a first base layer, said second ornamental layer comprising between 19 - 22 oz. cement/gypsum mixture, the ratio of gypsum to cement being 20 to 1, between 6.8 to 1.2 oz. water, and between 0.8 to 1.2 oz. acrylic resin.

20. The cementitious veneer of Claim 19, wherein said acrylic is selected from the group consisting of acrylic polymers, acrylic monomers, alkyl acrylates, methacrylates, lower alkyl acrylates, butadiene, and styrene.

21. The cementitious veneer of Claim 19. wherein said second ornamental layer further comprises pigment.

22. The cementitious veneer of Claim 19, wherein said second layer is ornamentally manipulated prior to drying.

23. The cementitious veneer of Claim 19, wherein said second layer is further finished after curing.

24. The cementitious veneer of Claim 19, wherein said surface is selected from the group consisting of wood, metal, masonry, fiberglass, gypsum board, fiberboard, and plastics.

25. The cementitious veneer of Claim 19, wherein said surface is prepared for bonding.

26. The cementitious veneer of Claim 19, wherein said first base layer mixture is prepared using emulsion polymerization.

27. A method for providing a cementitious veneer for a surface, comprising the steps of: coating said surface with at least a first base layer comprising a mixture of between 10% to about 60% by volume of acrylic latex, 10% to about 75% by volume of aggregate, water, surfactant, and between about 0.1 % to about 6% by volume polymerization catalyst; and applying over said at least a first base layer at least a second ornamental layer, said second ornamental layer comprising between 19 - 22 oz. cement/gypsum mixture, the ratio of gypsum to cement being 20 to 1, between 6.8 to 7.2 oz. water, and between 0.8 to lJ oz. acrylic resin.

28. The cementitious veneer of Claim 1, wherein said second ornamental layer constitutes an exposed outer surface of said cementitious veneer.

29. The cementitious veneer of Claim 1 , wherein the mixture of said first base layer is partially cured prior to the application of said second layer over said first base layer.

30. The cementitious veneer of Claim 19, wherein said second ornamental layer constitutes an exposed outer surface of said cementitious veneer.

31. The cementitious veneer of Claim 19, wherein the mixture of said first base layer is partially cured prior to the application of said second layer over said first base layer.

32. The method of Claim 27 further comprising the step of partially curing the mixture comprising said first base layer prior to said step of applying said second ornamental layer. AMENDED CLAIMS

[received by the International Bureau on 23 July 1999 (23.07.99); original claims 28-32 cancelled; original claims 1,2,14,15,19-21 and 27 amended; remaining claims unchanged (4 pages)]

What is claimed is:

1. A cementitious veneer, comprising: at least a first base layer comprising a mixture of acrylic latex, aggregate and water; and at least a second layer applied over said first base layer, said second layer comprising a mixture of cement, gypsum, acryiic resin, and water, wherein said second layer constitutes an exposed outer surface of said cementitious veneer, and wherein the mixture of said first base layer is cured to be in a hard state prior to the application of said second layer over said first base layer.

2. The cementitious veneer of Claim 1. wherein said acrylic is selected from the group consisting of acrylic polymers, acrylic monomers, alkyl acrylates. methacrylates. and lower alkyl acrylates.

3. The cementitious veneer of Claim 1. wherein said aggregate is selected from the group consisting of sand, gravel, silica, glass, ar.α crushed stone.

4. The cementitious veneer of Claim 1. further c mpπsing a surfactant added to said first base layer.

5. The cementitious veneer of Claim 4. wherein said surfactant is selected from the group consisting of anionic. cationic and non:on:c surfactants, salts of alkyl sulfates. alkylarene sulfates. alkyl

ethylenes. anc aryl polyoxyethylenes.

6. The cementitious veneer of Claim 1. further :cmpπsing a polymerization catalyst added to said first base layer in a concentration ?-_■ \ olume of between approximately 0.1 to approximately 6° n

9. The cementitious veneer of Claim 7, wherein said accelerator is selected from the group consisting of reducing agents and polyvalent metal salts.

10. The cementitious veneer of Claim 1, wherein said first base layer comprises between 10%) to about 60%) by volume of powdered monomer.

11. The cementitious veneer of Claim 1 , wherein said first base layer comprises between 10%o to about 75%o by volume of aggregate.

12. The cementitious veneer of Claim 1 , wherein said first base layer forms a layer having a thickness of between approximately 1/16 inch and approximately 1/8 inch.

14. The cementitious veneer of Claim 1 , wherein said second layer comprises approximately 20 parts cement/gypsum mixture. 7 parts water, and 1 part acrylic resin.

15. The cementitious veneer of Claim 1, wherein said second layer includes pigment.

17. The cementitious veneer of Claim 1 , wherein said second layer is ornamentally manipulated prior to drying.

18. The cementitious veneer of Claim 1 , wherein said second layer is further finished after curing.

19. A cementitious veneer for a surface, comprising:

at least a first base layer comprising a mixture of between 10% to about 60% by

volume of acrylic latex, 10% to about 75% by volume of aggregate, and water; a surfactant added to said first base layer mixture;

a polymerization catalyst added to said first base layer mixture, said polymerization catalyst comprising an initiator and an accelerator, said polymerization catalyst in a concentration by volume of between approximately 0J to approximately 6%;

and

at least a second layer applied over said first base layer, said second layer comprising approximately 20 parts cement/gypsum mixture, the ratio of gypsum to

cement being 20 to 1, 7 parts water, and 1 part acrylic resin, wherein said second layer

constitutes an exposed outer surface of said cementitious veneer, and wherein the mixture

of said first base layer is cured to be in a hard state prior to the application of said second

layer over said first base layer.

20. The cementitious veneer of Claim 19, wherein said acrylic is selected from the group consisting of acrylic polymers, acrylic monomers, alkyl acrylates, methacrylates, and lower alkyl acrylates.

21. The cementitious veneer of Claim 19, wherein said second layer further comprises

pigment.

23. The cementitious veneer of Claim 19. wherein said second layer is further finished after curing.

24. The cementitious veneer of Claim 19. wherein said surface is selected from the group consisting of wood, metal, masonry, fiberglass, gypsum board, fiberboard, and plastics.

26. The cementitious veneer of Claim 19. wherein said first base layer mixture is prepared using emulsion polymerization.

27. A method for providing a cementitious veneer for a surface, comprising the steps of:

coating said surface with at least a first base layer comprising a mixture of

between 10%> to about 60%> by volume of acrylic latex, 10% to about 75%) by volume of aggregate, water, surfactant, and between about 0.1% to about 6%> by volume polymerization catalyst; allowing the acrylic latex in said first base layer to cure to a hard state; and

applying over said first base layer at least a second layer, said second layer comprising approximately 20 parts cement gypsum mixture, the ratio of gypsum to cement being 20 to 1 ,

7 parts water, and 1 part acrylic resin, wherein said second layer constitutes an exposed outer surface of said cementitious veneer. Cited in the International Search Repoπ were US 2,760,885 (Larsen et al),

Material Safety Data Sheet, United States Gypsum Co. Product: HYDROSTONE,

Material Safety Data Sheet, Dryvit Systems Inc.. Product: PRIMUS, and US 5,447,752

(Cobb), as being of particular relevance such that the claimed invention cannot be

considered to involve an inventive step when the document is combined with one or more

other such documents, such combination being obvious to a person skilled in the art.

It is respectfully submitted that the amended claims included on the attached

substitute pages involve an inventive step that is not obvious to one skilled in the art in light

of the cited references, either alone or in combination.

It is further respectfully submitted that the amendments made to the claims do not

amend or otherwise impact the description and drawings as originally filed.