Patent Application
20050276960
The present invention relates generally to a sizing composition for glass fibers, and more particularly, to a sizing composition for wet use chopped strand glass fibers that contains a fatty amide lubricant synthesized from a (poly)ethylene amine and an unsaturated C5-C20 fatty acid. A composite roofing material formed from a reinforcing fiber material sized with the sizing composition is also provided.
Glass fibers are useful in a variety of technologies. For example, glass fibers are commonly used as reinforcements in the building composite industry because they do not shrink or stretch in response to changing atmospheric conditions. Roofing materials such as roofing shingles, roll roofing, and commercial roofing, are typically constructed of a glass fiber mat, an asphalt coating on the fibrous mat, and a surface layer of granules embedded in the asphalt coating.
To form a roofing shingle, glass fibers are first formned by attenuating streams of a molten glass material from a bushing or orifice. The molten glass may be attenuated by a winder which collects gathered filaments into a package or by rollers which pull the fibers before they are collected and chopped. An aqueous sizing composition is typically applied to the fibers after they are drawn from the bushing to protect the fibers from breakage during subsequent processing, to retard interfilament abrasion, and to improve the compatibility of the fibers with the matrix resins that are to be reinforced. After the fibers are treated with the sizing composition, they are packaged in their wet condition as wet use chopped strand glass (WUCS).
The wet, chopped fibers are then dispersed in a water slurry which may contain surfactants, viscosity modifiers, or other chemical agents and agitated to disperse the fibers. The slurry containing the dispersed fibers is then deposited onto a moving screen where a substantial portion of the water is removed to form a web. A binder is then applied, and the resulting mat is heated to remove the remaining water and cure the binder. Next, asphalt is applied to the mat, such as by spraying the asphalt onto one or both sides of the mat or by passing the mat through a bath of molten asphalt to place a layer of asphalt on both sides of the mat and fill in the interstices between the individual glass fibers. The coated mat is then cut to an appropriate shape and size to form the shingle.
Conventional sizing compositions for wet use chopped strand glass typically contain a film-forming polymeric or resinous component, a coupling agent, and a lubricant dissolved or dispersed in a liquid medium. Unfortunately, such conventional size compositions are not always compatible with the asphalt used to coat the fibrous mats and form the roofing shingles. Such incompatability may cause processing difficulties, and may result in roofing shingles that have poor physical properties, such as poor tear strength. Further, the amount of binder that is employed in conjunction with the conventional sizing compositions may significantly increase the cost of the roofing shingles.
Therefore, there exists a need in the art for an improved sizing composition for use in wet use chopped strand glass fibers that increases the compatibility of glass fiber mats to the asphalt coatings on asphalt composite articles, that lowers manufacturing costs, and that improves physical properties of the composite.
It is an object of the present invention to provide a sizing composition for wet use chopped strand fibers that includes one or more film forming agents, at least one coupling agent, and a fatty amide lubricant synthesized from a (poly)ethylene amine and a C5-C20 unsaturated fatty acid. The synthesized fatty amide compound is formed of an amine-based hydrophilic midsection with hydrophobic tails at either end. The hydrophobic tails are preferably conjugated and contain a high degree of unsaturation. In preferred embodiments, the (poly)ethylene amine is tetraethylenepentamine and the fatty acid is a conjugated fatty acid. The fatty amide lubricant may or may not be modified by an elastomer such as a maleinized rubber or a carboxylated rubber during the synthesis of the fatty amide lubricant. Secondary lubricants, viscosity modifiers, pH adjusters, biocides, and coalescents such as glycols and glycol ethers may also be included in the sizing composition. The reinforcing fiber material may be one or more strands of glass, natural fibers, carbon fibers, or one or more synthetic polymers. In at least one exemplary embodiment, glass fibers are sized with the sizing composition and packaged as wet use chopped strand glass that is subsequently used to form reinforced building or roofing composites such as shingles.
It is another object of the present invention to provide a composite roofing material that is formed of a plurality of glass fibers sized with a sizing composition that contains one or more film forming agents, at least one coupling agent, and a fatty amide lubricant synthesized from a (poly)ethylene amine and a C5-C20 unsaturated fatty acid as described above.
It is a further object of the present invention to provide a reinforced shingle product formed of a mat of randomly oriented glass fibers sized with a sizing composition that includes one or more film forming agents, at least one coupling agent, and a fatty amide lubricant synthesized from a (poly)ethylene amine and a C5-C20 unsaturated fatty acid as described above.
An advantage of the synthesized fatty amide lubricant is its built-in reactivity with asphalt when forming an asphalt roofing product. Covalent bonding between the glass and the asphalt may be established through a vulcanizing mechanism in which the unsaturated hydrophobic tails on the synthesized fatty amide react with the asphalt in the presence of sulfur at an elevated temperature and crosslink the glass and the asphalt. This interfacial bonding results in increased mechanical performance and improved tear strength in the composite article formed from fibers sized with the inventive sizing composition.
A further advantage of the synthesized fatty amide lubricant is that the high hydrophobicity and low surface energy of the hydrophobic tails on the fatty amide lubricant enhances the compatibility between the glass and the asphalt during the formation of asphalt roofing products and improves glass/asphalt interactions through the reduced interfacial tensions.
The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. It is to be noted that the phrases “size composition”, “sizing composition”, and “size” are used interchangeably herein.
The present invention relates to sizing compositions for wet use chopped strand glass fibers. The sizing composition includes one or more film forming agents, at least one coupling agent, and a fatty amide lubricant synthesized from a (poly)ethylene amine and a C5-C20 unsaturated fatty acid. The fatty amide lubricant may or may not be modified by an elastomer. Conventional lubricants, viscosity modifiers, pH adjusters, biocides, and coalescents such as glycols and glycol ethers may also be included in the sizing composition.
The film forming polymer component of the sizing composition may be any suitable polymer that can be dispersed or dissolved into an aqueous medium and which will coalesce to form a film when the sizing composition has been dried. In addition, the film former is desirably chosen to have compatibility with the matrix resin in which the sized glass fibers will be used. Examples of film forming agents for use in the size composition include polyester polymers, polyurethanes, acrylic polymers, vinyl polymers, mixtures of such polymers, copolymers of the corresponding monomers, carboxylic acid or anhydride modified polyolefins, cellulose, polyvinyl alcohols (PVA), and mixtures thereof. In a preferred embodiment, the film forming polymer is a polyvinyl alcohol, and in an even more preferred embodiment, the film forming polymer is a partially hydrolyzed polyvinyl alcohol having approximately 87-89% hydrolysis and a low to intermediate molecular weight. Examples of suitable polyvinyl alcohols for use in the size include Celvol 203, 205, and 325 from Celanese Chemicals. The film forming agent or agents may be present in the size composition in an amount of approximately 30-80% by weight of dry solids.
In addition, the sizing composition contains one or more coupling agents. Preferably, at least one of the coupling agents is a silane coupling agent. Silane coupling agents function to enhance the adhesion of the film forming polymer to the glass fibers and to reduce the level of fuzz, or broken fiber filaments, during subsequent processing. Examples of silane coupling agents which may be used in the size composition may be characterized by the functional groups amino, epoxy, vinyl, methacryloxy, ureido, isocyanato, and azamido.
Suitable silane coupling agents for use in the size include, but are not limited to, γ-aminopropyltriethoxysilane (A-1100), n-trimethoxy-silyl-propyl-ethylene-diamine (A-1120), γ-glycidoxypropyltrimethoxysilane (A-187), γ-methacryloxypropyltrimethoxysilane (A-174), n-β-aminoethyl-γ-aminopropyltrimethoxysilane (A-1120), methyl-trichlorosilane (A-154), methyl-trimethoxysilane (A-163), γ-mercaptopropyl-trimethoxy-silane (A-189), γ-chloropropyl-trimethoxy-silane (A- 143), vinyl-triethoxy-silane (A-151), vinyl-tris-(2-methoxyethoxy)silane (A-2171), vinyl-triacetoxy silane (A-188), octyltriethoxysilane (A-137), methyltriethoxysilane (A-162), methyltrimethoxysilane (A-1630), Silquest RC-1 vinyl silane, and Silquest RC-2 sulfur silane. All of the silane couplings agents listed herein are Silquest products available from GE Silicones. Preferably, the size composition contains both an aminosilane coupling agent and a vinyl silane coupling agent. The coupling agent or agents may be present in the sizing composition in an amount of from 5-30%, and preferably, in an amount of from 10-20% by weight of the dry solids.
The sizing composition also contains a fatty amide lubricant synthesized from a (poly)ethylene amine and an unsaturated C5-C20 fatty acid such as linoleic acid or oleic acid. In addition, vegetable-based unsaturated fatty acids such as, but not limited to, Agri-Pure 130 (Cargill, Inc.) and Agri-Pure 150 (Cargill, Inc.) may be used to synthesize the fatty amide lubricant. Preferably, the unsaturated fatty acid is a fatty acid containing conjugated double bonds such as linoleic acid, Edenor UKD 5010 (Cognis Corp.), Edenor UKD 5020 (Cognis Corp.), and EdenorUKD 6010 (Cognis Corp.). Non-exclusive examples of (poly)ethylene amines that may be used to form the fatty amide lubricant include tetraethylenepentamine (TEPA), diethylenetriamine (DETA), tetraethylenetriamine (TETA), ethylene diamine, diethylene triamine, triethylene tetramine, and pentaethylene hexamine. In preferred embodiments, the (poly)ethylene amine is tetraethylenepentamine. The synthesized fatty amide compound is formed of an amine-based hydrophilic midsection with hydrophobic tails at either end. The hydrophobic tails are preferably conjugated and contain a high degree of unsaturation. The fatty amide lubricant may be present in the size in an amount of from 5-30% by weight of the dry solids, and more preferably in an amount of from 10-20% by weight of the dry solids.
The fatty amide lubricant may be modified with an elastomer by incorporating a maleinized rubber or a carboxylated rubber during the synthesis of the fatty amide lubricant. Incorporating hydrophobic rubbers or elastomers in the synthesized fatty amide aids in reducing the surface energy of the glass fibers and in enhancing interactions between glass and asphalt. In addition, the elastomers may serve as an energy buffer or barrier to dissipate the energy passed between the high modulus rigid glass and low modulus soft asphalt when asphalt roofing products are subjected to an impact force. Examples of suitable maleinized rubbers include adducts of maleic anhydride and polybutadiene and adducts of maleic anhydric and polybutadiene styrene copolymers. The maleinized rubber or carboxylated rubber may be present in an amount of 5-40% by weight of the fatty amide lubricant, and even more preferably in an amount of from 10-30% by weight of the fatty amide lubricant.
In addition to the synthesized fatty amide lubricant, the size composition may also contain a secondary lubricant to facilitate manufacturing. The secondary lubricant may be any conventional lubricant such as, but are not limited to, water-soluble ethyleneglycol stearates (e.g., polyethyleneglycol monostearate, butoxyethyl stearate, and polyethylene glycol monooleate), ethyleneglycol oleates, ethoxylated fatty amines, glycerine, emulsified mineral oils, organopolysiloxane emulsions, stearic ethanolamide (sold under the trade designation Lubesize K-12 (Alpha/Owens Corning)), Stantex G-8145 (Cognis Corp.), SF-8275 (Cognis Corp.), and Emery 6760 (Cognis Corp). The secondary lubricant may be present in the size in an amount of from 0-10% by weight of the dry solids.
Optionally, the sizing composition may contain a viscosity modifier such as a polyacrylamide, a hydroxyethyl cellulose, or a polyamine viscosity modifier. Specific examples of viscosity modifiers include Nalco 7530 (ONDEO Nalco), 01PF067 (ONDEO Nalco), Superfloc C-507 (Cytec Industries, Inc.), Superfloc MX 40 (Cytec Industries, Inc.), Superfloc MX 80 (Cytec Industries, Inc.), and Superfloc SD-2065 (Cytec Industries, Inc.). The viscosity modifier acts as a secondary dispersant in the size composition. The viscosity modifier may be present in the sizing composition in an amount of from 0-5% by weight of the dry solids.
In addition, the size composition may optionally include a pH adjusting agent such as acetic acid, citric acid, sulfuric acid, or phosphoric acid in an amount sufficient to adjust the pH to a desired level. The pH may be adjusted depending on the intended application, or to facilitate the compatibility of the ingredients of the size composition. Preferably, the sizing composition has a pH of from 3-6, and more preferably a pH of from 4-5.
Further, the size may optionally contain conventional additives such as dyes, oils, fillers, thermal stabilizers, anti-foaming agents, anti-oxidants, dust suppression agents, wetting agents, and/or other conventional adjuvants. In addition, the size may include coalescents such as glycols and glycol ethers to aid in fiber storage stability and/or biocides such as Amerstad 250 (Ashland Chemicals) and Nalco 9380 (ONDEO Nalco).
The balance of the size composition is composed of water. In particular, water may be added to dilute the aqueous sizing composition to a viscosity that is suitable for its application to glass fibers and to achieve the desired solids content. The sizing composition may contain up to approximately 99.5% water.
The size composition may be applied to strands of glass formed by conventional techniques such as by drawing molten glass through a heated bushing to form substantially continuous glass fibers. Any type of glass, such as A-type glass, C-type glass, E-type glass, S-type glass, or modifications thereof, is suitable for use as the fiber material. For example, in one modification of E-type glass, the boron oxide is replaced by magnesium oxide. Such a glass is commercially available from Owens Coming Fiberglass Corporation under the trade name Advantex®.
Alternatively, the sizing composition may be applied to strands of one or more synthetic polymers such as polyester, polyamide, aramid, and mixtures thereof. The polymer strands may be used alone as the reinforcing fiber material, or they can be used in combination with glass strands such as those described above. As a further alternative, natural fibers may be used as the reinforcing fiber material. The term “natural fiber” as used in conjunction with the present invention to refers to plant fibers extracted from any part of a plant, including, but not limited to, the stem, seeds, leaves, roots or bast. Examples of natural fibers suitable for use as the reinforcing fiber material include cotton, jute, bamboo, ramie, hemp, flax, and combinations thereof. Carbon fibers may also be used.
The size composition is preferably applied to the fibers such that the size is present on the fibers in an amount of from about 0.02 to about 0.50 percent by weight based on the total weight of the fibers, and even more preferably in an amount of from about 0.05 to about 0.30 percent by weight. This can be determined by the loss on ignition (LOI) of the WUCS fibers, which is the reduction in weight experienced by the fibers after heating them to a temperature sufficient to burn or pyrolyze the organic size from the fibers. The size composition may be applied to fibers having a diameter of from about 6-23 microns, with fibers of from about 11-20 microns in diameter being more preferred.
The sizing composition may be applied to the fibers in any conventional maimer using any conventional applications such as by spraying or drawing the fibers to be sized across a rotating or stationary roll wet with the sizing composition. The size composition is preferably applied to the fibers in an amount sufficient to provide the fibers with a moisture content of from about 10% by weight to about 15% by weight of the WUCS fibers.
In preferred embodiments, glass fibers are sized with the sizing composition and packaged as wet use chopped strand glass that is subsequently used to form reinforced building or roofing composites such as shingles. For example, the sized glass fibers are chopped while wet and dispersed into a water slurry which may contain surfactants, viscosity modifiers, or other chemical agents. The slurry containing the dispersed fibers is then deposited onto a moving screen where a substantial portion of the water is removed. Next, a binder (e.g., a urea formaldehyde binder or a polycarboxylic acid based binder) is applied, and the resulting mat is dried to remove the remaining water and cure the binder. The formed non-woven mat is an assembly of randomly oriented, dispersed, individual glass filaments. The mat may be dried by in any conventional manner, such as by passing the mat through an oven. Asphalt is then applied to the dried/cured mat in any known manner, such as by passing the mat through a bath containing an asphalt mix that may include molten asphalt, fillers, and optionally sulfur to place a layer of asphalt on at least one side of the mat and fill in the interstices between the individual glass fibers. The asphalt-coated mat is then cut to the appropriate shape and size to form a shingle. The hot asphalt-coated mat may then be passed beneath one or more granule applicators which apply protective surface granules to portions of the asphalt-coated mat prior to cutting into the desired shape.
The synthesized fatty amide is designed not only to function as a lubricant and a dispersant, but also to interact with the asphalt in the asphalt mix. Thus, one advantage provided by the fatty amide is its built-in reactivity with other components. For example, covalent bonding (e.g., interfacial bonding) between the glass and the asphalt can be established through a vulcanizing mechanism in which the unsaturated hydrophobic tails on the synthesized fatty amide react with the asphalt in the presence of sulfur at an elevated temperature and crosslink the glass and the asphalt. In this reaction, the sulfur acts as a catalyst. The interfacial bonding between the glass and the asphalt increases the mechanical strength of the resulting composite article.
In addition, the nitrogens present in the hydrophilic amine-based mid section of the synthesized fatty amide, once neutralized with an acid, become cationic nitrogens. These cationic nitrogens may then form ionic bonds with the anionic charge of the glass fibers which helps to anchor the fatty amide lubricant onto the glass fibers.
Another advantage provided by the fatty amide is that the fatty amide modifies the surface energy of the glass to make the glass more compatible with the asphalt. The high hydrophobicity and low surface energy of the hydrophobic tails on the fatty amide lubricant enhances the compatibility between the glass and the asphalt and improves glass/asphalt interactions through the reduced interfacial tensions. Thus, the new fatty amide also acts as an adhesion promoter.
Having generally described this invention, a further understanding can be obtained by reference to certain specific examples illustrated below which are provided for purposes of illustration only and are not intended to be all inclusive or limiting unless otherwise specified.
Lubesize K-12 is a conventional lubricant that is an adduct of tetraethylenepentamine (TEPA) and stearic acid. It has no degree of unsaturation. The ingredients used to synthesize Lubesize K-12 are set forth in Table 1.
Table 2 illustrates a 1 kg charge based on the ingredients set forth in Table 1.
The stearic acid was charged and melted at 200° F. under a light nitrogen blanket. Once all of the stearic acid was melted, it was agitated under a nitrogen blanket. When the temperature was controlled at 200° F., the heat was removed. Tetraethylenepentamine (TEPA) was then slowly added from a dropping funnel. After an exotherm peak, the heating was resumed. Once all of the TEPA was added, the temperature was raised as fast as the foaming permitted. At approximately 380° F., it was determined that approximately 50% of the distillate had been removed. At this time, the nitrogen blanket was removed and a low nitrogen sparge was applied.
After the low nitrogen sparge was applied, heat was again applied towards a maximum temperature of 480° F. until the distillate stopped. Once the distillate had stopped, the reaction mixture was cooled to a temperature of approximately 160-170° F. by ambient air. The total distillate removed from the stearic acid and TEPA was determined to be approximately 12% of the total charge. Acetic acid was then added over a period of approximately 15 minutes. A slight exotherm of approximately 10° F. was noted as the acetic acid was added. After all of the acetic acid was added, the mixture was agitated for approximately 10 minutes and then poured onto release paper where it was permitted to cool and solidify.
The final product at 1% in water had a pH in the range of 4.5-5.0. In addition, the final product prior to acid neutralization had a residual acid value of 0.4% and a non-detectable iodine value. The solidified product was determined to be Lubesize K-12.
The experiment set forth in Example 1 was repeated except that stearic acid was replaced with linoleic acid on an equivalent basis. The linoleic acid used was Emersol 315 linoleic acid from Cognis Corp. The finished product prior to acid neutralization had a residual acid value of 0.29% and an iodine value of 24.8. The iodine value of Emersol 315 linoleic acid was 27.4. It was determined that approximately 90.5% of the unsaturation in the fatty acid was maintained in the synthesized product.
The experiment set forth in Example 1 was repeated except that stearic acid was replaced with oleic acid on an equivalent basis. The oleic acid used was Emersol 213 oleic acid from Cognis Corp. The synthesized product prior to acid adjustment had a residual acid value of 0.18% and an iodine value of 21.8. The iodine value of Emerson 213 oleic acid was 24.3. It was determined that approximately 90% of the unsaturation in the fatty acid was maintained in the synthesized product.
The experiment set forth in Example 1 was repeated except that the stearic acid was replaced with 90% of Emersol 315 linoleic acid (Cognis Corp.) and 10% Ricon 130MA13 maleinized polybutadiene (Sartomer) on a weight basis. The synthesized product prior to acid neutralization had a residual acid value of 0.21% and an iodine value of 27.7. The iodine value of the raw mixture of linoleic acid and maleinized polybutadiene prior to the condensation reaction was 36.3. It was determined that 76.3% of the unsaturation in the fatty acid was retained in the synthesized product.
The experiment set forth in Example 1 was repeated except that the stearic acid was replaced with 90% of Emersol 315 linoleic acid (Cognis Corp.) and 10% Ricon 184MA6 maleinized polybutadiene styrene rubber (Sartomer) on a weight basis. The iodine content of the starting raw mixture of linoleic acid and polybutadiene styrene rubber prior to the condensation reaction was 32.2. The synthesized product prior to acid neutralization had a residual acid value of 0.25% and an iodine value of 30.7. It was determined that approximately 95.3% of the unsaturation of the fatty acid was maintained in the synthesized product.
Fiber samples were coated with sizing compositions containing the fatty amides prepared in Examples 1 and 2 above. The sized fiber samples were formed into roofing mats on a sheet former. The mat samples were then converted to lab shingle samples by coating the mats with an asphalt mix containing 0%, 0.2%, or 0.8% post-added elemental sulfur. The results are summarized in Table 3.
Note: CD cross direction
Tear strengths were measured on an Elmendorf Tear Strength Tester following the procedure set forth in ASTM D-3462 Units for tear strength are in grams
The performance improvement data in this Example shows that a lab shingle formed from fibers sized with a sizing composition containing a fatty amide synthesized from TEPA and a conjugated fatty acid had improved tear strength with or without external sulfur in the asphalt coating formulation. Although not wishing to be bound by theory, it is believed that the increased performance in the sizing compositions when no sulfur was added was due to the higher hydrophobicity and reduced surface energy of the glass surface by the inventive fatty amide. It is also believed that the reduction of the surface energy improves interactions between the glass and the asphalt added to form the lab shingle.
Fiber samples were coated with sizing compositions containing the fatty amides prepared in Examples 1 and 3 above. The sized fiber samples were formed into roofing mats on a sheet former. The mat samples were then converted to lab shingle samples by coating the mats with an asphalt mix containing 0% and 0.2% post-added elemental sulfur. The results are summarized in Table 4.
Note: CD = cross direction
Tear strengths were measured on an Elmendorf Tear Strength Tester following the procedure set forth in ASTM D-3462 Units for tear strength are in grams
The performance improvement data in this Example shows that a lab shingle formed from fibers sized with a sizing composition containing a fatty amide synthesized from TEPA and a non-conjugated unsaturated fatty acid had improved tear strength with or without external sulfur in the asphalt coating formulation.
The invention of this application has been described above both generically regard to specific embodiments. Although the invention has been set forth in what ed to be the preferred embodiments, a wide variety of alternatives known to those of he art can be selected within the generic disclosure. The invention is not otherwise except for the recitation of the claims set forth below.
