Low VOC asphalt composition

Abstract

An asphalt composition having a low VOC content composed of an asphalt material; a volatile methylated siloxane from the group of linear methylated siloxane, cyclic methylated siloxane, branched methylated siloxane and any mixtures thereof and fillers, additives organic VOC solvents conventionally used in such a composition, wherein the composition has a VOC level that allows the composition to be used in venues having restricted low levels of VOC.

Claims

1. A low volatile organic compound (VOC) composition comprising: a) 20-70% by weight of an asphalt material, b) 5-30% by weight of a volatile methylated siloxane selected from the group consisting of linear methylated siloxane, cyclic methylated siloxane, branched methylated siloxane and any mixtures thereof; and c) 10-50% by weight of fillers, additives and organic VOC solvents; wherein the composition has a VOC of 150 g/l and lower.

2. The composition of claim 1 containing thickeners.

3. The composition of claim 1 wherein the organic VOC solvents comprise Stoddard solvent.

4. The composition of claim 1 wherein the volatile methylated siloxane comprises octamethylcyclotetrasiloxane.

5. The composition of claim 4 wherein the asphalt material comprises an asphalt having a penetration grade of about 0.5-30.

6. The composition of claim 1, wherein the composition has a VOC of 10-150 g/l.

7. The composition of claim 1, wherein the volatile methylated siloxane is selected from: linear hexamethyldisiloxane; linear octamethyltrisiloxane; linear decamethyltetrasiloxane; linear dodecamethylpentalsiloxane; linear tetradecamethylhexasiloxane; linear dimethyl silicones; linear dimethyl siloxanes; hexamethylcyclotrisiloxane; octamethylcyclotetrasiloxane; cyclic decamethylcyclopentasiloxane; dodecamethylcyclohexasiloxane; cyclopolydimethylsiloxane; branched 1,1,1,3,5,5,5-heptamethyl 3-[(trimethylsilyl)oxyl]-trisiloxane (C.sub.10H.sub.30O.sub.3Si.sub.4); branched 1,1,1,5,5,5-hexamethyl-3,3,-bis[(trimethylsilyl)oxy]-trisiloxane (C.sub.12H.sub.36O.sub.4Si.sub.5); branched pentamethyl[(trimethylsilyl)oxy]-cyclotrisilozane (C.sub.8H.sub.24O.sub.4Si.sub.4); blends thereof; and mixtures thereof.

8. The composition of claim 7, comprising 5-20% by weight of said volatile methylated siloxane.

9. The composition of claim 8, wherein said volatile methylated siloxane is octamethylcyclotetrasiloxane.

10. The composition of claim 1, wherein the asphalt material comprises an asphalt having a penetration grade of about 0.5-60.

11. The composition of claim 1, wherein the asphalt material is air-blown.

12. The composition of claim 1, wherein the asphalt material is non-air-blown.

13. An asphalt cut back intermediate composition comprising: a) 20-70% by weight of an asphalt material, b) 5-30% by weight of a volatile methylated siloxane selected from the group consisting of linear methylated siloxane, cyclic methylated siloxane, branched methylated siloxane and any mixtures thereof; and c) organic VOC solvents; wherein the composition has a VOC of 150 g/l and lower.

14. The composition of claim 13, wherein the asphalt material comprises an asphalt having a penetration grade of about 0.5-30.

15. The composition of claim 13, wherein the volatile methylated siloxane is selected from: linear hexamethyldisiloxane; linear octamethyltrisiloxane; linear decamethyltetrasiloxane; linear dodecamethylpentalsiloxane; linear tetradecamethylhexasiloxane; linear dimethyl silicones; linear dimethyl siloxanes; hexamethylcyclotrisiloxane; octamethylcyclotetrasiloxane; cyclic decamethylcyclopentasiloxane; dodecamethylcyclohexasiloxane; cyclopolydimethylsiloxane; branched 1,1,1,3,5,5,5-heptamethyl 3-[(trimethylsilyl)oxyl]-trisiloxane (C.sub.10H.sub.30O.sub.3Si.sub.4); branched 1,1,1,5,5,5-hexamethyl-3,3,-bis[(trimethylsilyl)oxy]-trisiloxane (C.sub.12H.sub.36O.sub.4Si.sub.5); branched pentamethyl[(trimethylsilyl)oxy]-cyclotrisilozane (C.sub.8H.sub.24O.sub.4Si.sub.4); blends thereof; and mixtures thereof.

16. The composition of claim 13, wherein the asphalt material comprises an asphalt having a penetration grade of about 0.5-60.

17. The composition of claim 13, comprising 5-20% by weight of said volatile methylated siloxane.

18. The composition of claim 13, wherein said volatile methylated siloxane is octamethylcyclotetrasiloxane.

19. The composition of claim 13, wherein the asphalt material is air-blown.

20. The composition of claim 13, wherein the asphalt material is non-air-blown.

Description

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(1) The novel asphalt composition of this invention has a low level of VOC and can be used in areas wherein EPA requires low VOC levels that cannot be obtained with current asphalt containing compositions formulated with conventional organic solvents.

(2) The asphalt composition of this invention is a low level VOC composition having a VOC of 150 g/l and lower. VOC levels can vary depending on the composition and its use in ranges of 10-150 g/l, 25-125 g/l, 75-140 g/l and the like.

(3) To determine the VOC of the composition either of the following two methods can be used: 1. EPA 24 (U.S. Environmental Protection Agency Technology Transfer Network Emission Measurement Center Method 24), incorporated herein, measures the VOC content of a composition and excludes ingredients exempted by regulatory authorities. 2. The SCAQMD method, incorporated herein, is a calculation based on EPA 24 for measuring the VOC content of a composition according to Rule 1113, adopted Sep. 2, 1977, amended Feb. 5, 2016 and Rule 1168, adopted Apr. 7, 1989, amended Jan. 7, 2005.

(4) As used herein, all percentages expressed are in weight percentages and refer to the percentages in the overall composition unless otherwise noted.

(5) The composition of this invention comprises a mixture of asphalt, a solvent of methylated siloxane(s) and fillers, additives and a lower amount of organic VOC solvents. Generally, the composition contains about 20 to 70% by weight of asphalt and preferably, 35 to 65% by weight of asphalt; 5 to 30% by weight of the methylated siloxane solvent and preferably 5 to 20% by weight the methylated siloxane solvent and 10 to 50% by weight of fillers, additives and organic VOC solvent and preferably 15 to 40% by weight of such fillers, additives and solvents.

(6) Solvents

(7) The methylated siloxane solvent used in the composition is an exempted solvent in the determination of the VOC of the composition. These methylated siloxanes dissolve or partial dissolve or plasticize the asphalt of the composition and are listed as exempted solvents by the SCAQMD. One such solvent is Xiameter PMX-0244 from Dow Corning. Compositions containing such methylated siloxane solvents meet VOC requirements of the region and can be marketed as VOC compliant and as either low or very low VOC compositions. The following are methylated siloxane solvents that are useful in formulating the compositions of this invention:

(8) Linear completely methylated siloxanes, such as hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentalsiloxane, tetradecamethylhexasiloxane, dimethyl silicones and siloxanes and the like;

(9) Cyclic completely methylated siloxanes, such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, cyclopolydimethylsiloxane and the like; and

(10) Branched completely methylated siloxanes, such as 1,1,1,3,5,5,5-heptamethyl 3-[(trimethylsilyl)oxyl]-trisiloxane (C.sub.10H.sub.30O.sub.3Si.sub.4), 1,1,1,5,5,5-hexamethyl-3,3,-bis[(trimethylsilyl)oxy]-trisiloxane (C.sub.12H.sub.36O.sub.4Si.sub.5), pentamethyl[(trimethylsilyl)oxy]-cyclotrisilozane (C.sub.8H.sub.24O.sub.4Si.sub.4) and the like.

(11) The composition can contain VOC solvents such as Stoddard solvent which is a man-made organic solvent from refining crude oil and is a petroleum mixture of distilled alkanes, cycloalkanes (naphthenes) and aromatic compounds. An example of such a solvent is ShellSol D38 from Shell Chemicals. Aromatic solvents such as ShellSol A100 from Shell Chemicals may also be used. Hydrotreated heavy naphthenic petroleum distillates, such as FJC Mineral Oil, may also be used.

(12) The level of these organic VOC solvents is kept to a minimum to maintain the VOC of the resulting composition at or below 150 g/l. Typically, about 1-20% by weight, based on the weight of the composition, of the organic VOC solvents are used in formulating the composition.

(13) Asphalt

(14) Various grades of asphalts can be used to formulate the composition of this invention and include asphalts used for paving, roofing, caulking and sealing and blended asphalts, asphaltenes and recycled asphalts. Useful asphalts can be air blown or non-air blown. Particularly useful grades of asphalts include AC 20 having a performance grade of 64-22. Other grades of asphalt include asphalts having a penetration grade up to 300 can be used. Asphalts having a penetration grade of 60 or less, such as, 40. A range of about 0.5-30 is preferred. The penetration grade of asphalt is an index showing the hardness of the asphalt by determining the penetration of a probe into the asphalt at a temperature of 25? C. under a predetermined load and time. For some applications, DA asphalt (de-asphaltized asphalt) may be used, i.e., asphalt that has a substantially low oil content due solvent extraction during refining process.

(15) Fillers and Additives

(16) Fillers and additive can be added to the composition of this invention that are commonly used in asphaltic compositions and are not limited to the examples listed below. Fine particles of limestone, calcium carbonate, for example, from United States Lime and Minerals, and other particles and pigments also can be added. Typically, limestone having a nominal mesh of 100 or finer is used. Expanded perlite (treated or untreated), such as, Harborlite 900 from Imerys, diatomaceous earth, glass spheres, fly ash, mica, talc, sand, wollastonite and clay are a partial listing of useful fillers.

(17) A variety of type, grade, and particle size of clay can be used. The clay can be a low-swell clay, a medium-swell clay or a high-swell clay. Attapulgite clay, such as, Attagel 15 from BASF is an example of clay that can be used and is a naturally occurring mineral of a crystalline hydrated magnesium alumino-silicate. Other clays, such as bentonite, sepiolite or kaolin clays, also can be used.

(18) Fibers, such as, cellulosic fibers as CF-325 from Central Fiber, polyolefin fibers, fiber glass, fibers of recycled plastics, and aramid fibers (Kevlar?) can be utilized. Fibers can be selected according to length and diameter and ability to absorb liquids to provide the composition with the desired degree of workability.

(19) Suitable polymers and polymeric adhesive can be used that include natural rubber, synthetic rubber, thermoplastic rubber, styrene/butadiene/styrene (SBS) polymers, such as Butofan NS 299 from BASF, ethylene vinyl acetate (EVA) polymers, acrylic polymers, polyurethane polymers, styrenated-acrylic polymers, styrene/butadiene copolymers, polymers of (meth)acrylic acid esters, polyamides polycarbonates, polyesters and thermoplastic polyurethanes.

(20) Surfactants can be added, for example, alkyloxy-alkylamine salts, such as, isodecyloxypropyl amine acetate salt surfactant, chlorine stable, low foaming, hydrotrope surfactant Surtech from Surface Chemists of Florida, alkoxylated fatty amines, alkoxylated ether amines and quaternary ammonium salts.

(21) Additional additives include colorants, aluminum flakes to improve adhesion, such as, AD-HERE 260 LE from ArrMaz, and additives that improve workability, ductility and product life. Aluminum and or other pigments, dyes can be added to improve aesthetics of the composition or for reflectivity or to improve chemical or corrosion resistance or weather related performance resistance. Typically, aluminum roof coatings and adhesives use such additives.

(22) Compositions of this invention are useful, for example, in roofing cements and flashing cements that are environmentally safer than traditional VOC containing compositions and are non-toxic in use and afterwards. Such compositions are workable at ambient temperatures, easy to apply and can be stored over a wide range of temperatures.

(23) Process for Preparation

(24) The compositions of this invention are prepared by adding a portion of the asphalt to a blend of an organic VOC solvent and the methylated siloxane solvent and dissolved. Generally, the adhesion promoter is added and mixed, followed by the surfactant and mixed until homogeneous and other additives, such as, clay (attapulgite clay) is added. Typically, additional portions of the asphalt solvent mixture are added along with additional additives, such as, perlite and cellulose and mixed and blended as necessary to form a homogeneous mixture. Depending on the composition being formulated, additional portions of other additives, such as, limestone particles and other polymer compositions are added and mixed therein. One skilled in the art will utilize the required mixing procedure to form a homogeneous composition useful for its designed purpose.

(25) The following are non-limiting examples that illustrate the invention. The VOC of compositions of the Example are determined using the SCAQMD METHOD described above.

EXAMPLE

(26) The following shows the formulations of asphalt cut back intermediate compositions that are utilized in forming a cement composition. The composition of the invention provides an approximate 50% VOC reduction in comparison to the control that is a conventional composition that typically is used.

(27) TABLE-US-00001 TABLE 1 Composition of Low-VOC Asphalt Cutback Compared to Control % by Weight Invention Control Components Asphalt (PG 64-22, AC-20 Grade) 69.7 74.7 Stoddad Solvent (ShellSol D 38) 13.3 25.3 Octamethylcyclotetrasiloxane 17 0 Property VOC (g/l) 129 240

Example 1

(28) The following low VOC cement composition and a control cement composition were formulated:

(29) TABLE-US-00002 TABLE 2 Composition of Low-VOC Cement Compared to Control % by Weight Invention Control Components Asphalt (PG 64-22, AC-20 Grade) 43.31 42.95 Calcium Carbonate (Nominal 100 Mesh or Finer) 25.21 25.74 Octamethylcyclotetrasiloxane 10.54 0.00 Stoddard Solvent (ShellSol D38) 8.29 18.40 Cellulose Fiber (CF-325/Interfiber ETF of JMC) 4.48 4.58 Attapulgite Clay, (Attagel 15/Minugel FG) 4.20 4.29 Expanded Perlite, Sil-Cell 35 BC/H900 2.52 2.57 SBR Latex, Butofan NS-299 0.88 0.90 Alkykdiamine Surfactant (Surtech AS-309) 0.48 0.49 Amidoamine Adhesion Promoter 0.08 0.09 (AD-HERE 260 LE/MWV PC-1717) Property Density (lbs/gal) 9.17 8.96 VOC (g/l) 98.16 205.54 Asphalt (%) (35-65% per ASTM D 4586) 43.31 42.95 Water (%) (Maximum 3% per ASTM D 4586) 0.83 .84 Filler (%) (15-40% per ASTM D 4586) 35.99 36.75 Nonvolatile Content (%) Minimum 79.78 80.19 70% per ASTM D 4586) Solvent (%) 18.83 18.40 Polymer (%) 0.48 .49

(30) TABLE-US-00003 TABLE 3 Ingredient and Order of Addition to Prepare Low-VOC Cement Quantity (g) Asphalt Cutback prepared above (Asphalt PG 463.9 64-22, AC-20 Grade in Stoddard Solvent and Octamethylcyclotetrasiloxane) Add by weight Amidoamine Adhesion Promoter 1.3 (AD-HERE 260 LE/MWV PC-1717) Add by weight, mix until homogeneous Alkyldiamine Surfactant (Surtech AS-309) 7.6 Add by weight, mix until homogeneous Attapulgite Clay (Attagel 15/Minugel FG) 67.2 Add by weight, mix for 15 minutes Asphalt Cutback 228.8 Add by weight, mix until homogeneous Expanded Perlite (Sil-Cell 35 BC/H900) 40.3 Add by weight, mix until homogeneous Cellulose Fiber (CF-325/Interfiber ETF or JMC) 44.8 Add by weight, mix until homogeneous Asphalt Cutback 153.1 Add by weight, mix until homogeneous Cellulose Fiber (CF-325/Interfiber ETF or JMC) 26.9 Add by weight, mix until homogeneous Asphalt Cutback 148.4 Add by weight, mix until homogeneous Limestone (Nominal 100 Mesh or Finer) 403.4 Add by weight, mix until homogeneous SBR Latex, Butofan NS-299 14.1 Add by weight, mix until homogeneous

(31) The composition of the invention showed a better than 50% VOC reduction in comparison to the control. Each cement composition prepared above was tested for the following physical requirements set forth in ASTM D 4586 for a Type I, Class II Asphalt Roof Cement.

(32) UniformityA thoroughly stirred sample did not show separation of solvent or settling that could not be overcome by moderate stirring after 72 hours at room temperature in a closed container.

(33) WorkabilityThe cement is of a consistency that will spread readily and permit troweling smooth coatings 2 mm to 6 mm thick on prepared roofing, saturated felt and metal surfaces at ambient temperatures of above 10? C.

(34) Behavior at 60? C. The cement shows no evidence of blistering; sag or slide is no greater than 6 mm.

(35) Pliability at 0? C. No cracking or separation of the cement from a metal substrate after application was shown.

(36) Both the low VOC composition and the control prepared above had acceptable physical properties for uniformity, workability, behavior at 60? C. and pliability at 0? C.

(37) Under Water Adhesion

(38) ASTM D 3409 adhesion test is used to determine the adhesion of the cement underwater. The cement is placed on a metal lid and placed underwater and a second flamed metal lid is pressed into the lid while under water. The lids are removed from the water and separated to evaluate if the cement adhered to the flamed lids. The amount of surface that remains coated is estimated and reported. Both the low VOC composition and control prepared above showed 100% underwater adhesion of the composition to the lids.

(39) The above cement composition of the invention had all of the above physical requirements and was considered commercially acceptable as was the control. The desired advantage of the composition of the invention is that it had the desired low VOC content in comparison to the control.

Examples 2-5

(40) Examples 2-5 were prepared according to the invention as above and compared to the control of Example 1.

(41) TABLE-US-00004 TABLE 4 Composition of Low-VOC Cement Compared to Control % by Weight Exam- Exam- Exam- Exam- ple 2 ple 3 ple 4 ple 5 Components Asphalt (PG 64-22, AC-20 Grade) 43.31 40.91 Asphalt (AC-5 Grade) 48.80 55.14 Calcium Carbonate 25.21 9.5 6.05 25.76 Octamethylcyclotetrasiloxane 10.54 11.73 8.07 14.21 Stoddard Solvent 8.29 1.29 1.80 Aromatic Solvent 8.61 9.74 7.83 Cellulose Fiber 4.48 8.30 6.13 4.58 Attapulgite Clay 4.20 9.72 5.07 2.14 Expanded Perlite 2.52 6.55 2.58 SBR Latex 0.88 0.35 0.36 0.90 Alkykdiamine Surfactant 0.48 1.55 1.00 0.49 Amidoamine Adhesion Promoter 0.08 0.15 0.09 0.60 Property Density (lbs/gal) 9.17 9.38 7.33 9.16 VOC (g/l) 98.16 123.47 107.37 91.98 Asphalt (%) (35-65% per 43.31 48.80 55.14 40.91 ASTM D 4586) Water (%) (Maximum 3% per 0.83 1.14 0.67 0.63 ASTM D 4586) Filler (%) (15-40% per 35.99 26.55 23.30 34.84 ASTM D 4586) Nonvolatile Content (%) 79.78 88.01 87.19 76.83 Minimum 70% per ASTM D 4586) Solvent (%) 18.83 21.62 19.60 22.04 Polymer (%) 0.48 0.19 0.19 0.49

(42) Each of the compositions of Examples 2-5 had a significantly lower VOC than the control of Example 1. Also each of the compositions of Examples 2-5 had acceptable physical properties as set forth in Example and with the advantage of low VOC.