Architectural compositions with improved gloss retention

Abstract

Combinations of UV absorber(s) and / or UV scavengers) to be added to paints and stains to improve gloss retention of the paint films are disclosed. A method of dissolving a solid, water insoluble UV absorber in a liquid, water dispersible UV absorber before adding to paints and stains is also disclosed.

Description

ARCHITECTURAL COMPOSITIONS WITH IMPROVED GLOSS RETENTION FIELD OF THE INVENTION

[8001] The present invention relates to aqueous architectural coating compositions, such as paints and stains, that have improved gloss retention. Specifically, the present invention relates to additives that are post-added to the aqueous architectural coating compositions to improve their gloss retention.BACKGROUND OF THE INVENTION

[0002] Exterior low-VOC (volatile organic compound) aqueous paints are exposed to sunlight including UV radiation, electromagnetic radiation in the visible range, rain, fog, winds, and other adverse environmental factors. Prolonged environmental exposure reduces the glossy appearance particularly for exterior paints with higher initial gloss or sheen. Environmental exposure can also result in a loss of color and increased dirt pickup. The patent literature has reported that aqueous acrylic paints have poor gloss retention losing as much as 70% of gloss from 2,000 hours of exposure. UV absorbers have been added to exterior paints and stains as additives to reduce loss of gloss.

[0003] UV absorbers alone are not sufficient to optimize gloss retention. As discussed in “Additives Reference Guide” by J.V. Koleske, R. Springate and D. Brezinski (2013), available at www.PCIMag.com, UV absorbers are often used with a UV scavenger additive, e.g., a hindered amine light stabilizer (HALS). Koleske et al. stated that UV absorbers are not able to absorb all the UV radiation that the paint films are exposed. Some of the UV radiation penetrate the coating’s surface. HALS’s scavenge free radicals that form within the paint film. HALS’s differ from UV absorbers in that HALS’s remove free radicals from the system and can regenerate themselves.

[0004] The patent literature also discloses a combination of UV absorber and UV scavenger additives, such as photo-initiators and HALS, respectively, to retain gloss. Commonly owned U.S. patent No. 7,754,801 entitled “Translucent Coating Composition Providing Improved UV Degradation Resistance,” teaches a combination of HALS and UV absorber to reduce UV degradation on exterior architectural compositions, i.e., “about 0.41 parts TINUVIN™ 292 (a hindered amine light stabilizer, HALS commercially available from CIBA®) and about 0.69 parts TINUVIN™ 1 130 (a hydroxyphenylbenzotriazole UV absorber, commercially available from CIBA®)” are added to stain compositions. Tinuvin 292 is acombination of (a) bis (1, 2, 2, 6, 6-pentamethyl-4-piperidyl) sebacate and (b) methyl 1, 2, 2, 6, 6- pentamethyl-4-piperidyl sebacate.[0005 j Also reported in the patent literature, benzophenone (BP) photo-initiator has been traditionally added to exterior paints and stains as a UV absorber to improve gloss retention. However, BP is a VOC and its use is being significantly restricted by environmental regulations.

[0006] Substitutes for BP have been suggested in the patent literature. Water insoluble derivatives of BP either alone or with a HALS or coalescent aid are added to paints. Commonly known water insoluble BP derivatives are solid, water insoluble and non- dispersible in water and in aqueous architectural compositions. To mix the insoluble BP derivative photo-initiator to the aqueous architectural compositions, the insoluble BP derivative photo-initiator is first dissolved in acetone or in a coalescent aid. Alternatively, the insoluble photo-initiator is admixed while the latex resins are still at a high temperature typically at the end of a polymerization reaction to melt the photo-initiator. While acetone is legally exempted as a VOC in the environmental regulations, it is a highly volatile, flammable liquid with a characteristic pungent odor. Acetone is commonly used as nail polish remover and paint thinner. Some coalescent aids are volatile compounds and are not needed in all paints. Unnecessarily adding coalescent aids into a paint can adversely affect the properties of paint films. Adding the insoluble photo-initiators or UV absorbers to a high temperature polymer solution restricts its application to the final step in the polymerization process before natural convection cooling occurs, and is impractical.

[0007] Hence, there is a need to overcome the known deficiencies in the art.

[0008] There also remains a need to improve gloss retention in exterior paints or stains, more specifically a need for paint additives, including but not limited to photo-initiators with or without other additives such as HALS, that can be added to architectural coating compositions at any point in the manufacturing process, including post-adding to the architectural coating compositions after the architectural coating compositions are manufactured.SUMMARY OF THE INVENTION

[0009] Hence, the invention is directed to an aqueous architectural composition comprising:- a polymeric latex resin,“ ail optional opacifying pigment,- a water dispersible, liquid UV absorber, wherein the water dispersible, liquid UV absorber comprises 2 -methylbenzophenone- a UV scavenger, wherein the UV scavenger comprises a hindered amine light stabilizer (HALS):~ wherein the water dispersible UV absorber ranges from about 0.50 to about 11.0 wt.% based on polymer solids, preferably from about 1.0 to about 10.5 wt.% based on polymer solids, preferably from about 1.25 to about 10.25 wt.% based on polymer solids, preferably from about 1 .5 to about 10.0 wt.% based on polymer solids; and- wherein the HALS ranges from about 0.1 to about 3.0 wt.% based on polymer solids, preferably from about 1.0 to about 2.5 wt.% based on polymer solids, preferably from about 1.50 to about 2.0 wt.% based on polymer solids.

[0010] The invention is also directed to an aqueous architectural composition comprising:- a polymeric latex resin,- an optional opacifying pigment,- a solid, water insoluble UV absorber, wherein the water insoluble UV absorber comprises either 4-methyIbenzophenone or benzophenone, or both,~ a liquid, water dispersible UV absorber, wherein the liquid, water dispersible UV absorber comprises 2 -methylbenzophenone, wherein the solid, water insoluble UV absorber is dissolved in the liquid, water dispersible UV absorber,- a UV scavenger, wherein the UV scavenger comprises a hindered amine light stabilizer (HALS);~ wherein the solid, water insoluble UV absorber ranges from about 0.03 to about 4.0 wt.% based on polymer solids, preferably from about 0.10 to about3.5 wt.% based on polymer solids, preferably from about 0.40 to about 3.0 wt.% based on polymer solids;- wherein the liquid, water dispersible UV absorber ranges from about 0.25 to about 6.5 wt.% based on polymer solids, preferably from about 0.30 to about5.5 wt.% based on polymer solids, preferably from about 0.35 to about 4.0 wt.% based on polymer solids, preferably from about 1.25 to about 3.5 wt.% based on polymer solids;- wherein the HALS ranges from about 0.10 to about 4,0 wt.% based on polymer solids, preferably from about 0.25 to about 3.5 wt.% based on polymer solids, preferably from about 0.40 to about 3.0 wt.% based on polymer solids, and- wherein a combined insoluble UV absorber, liquid, water dispersible UV absorber and HALS range from 0.5 wt.% based on polymer solids to a sum of the highest values of the combined insoluble UV absorber, liquid, water dispersible UV absorber and HALS based on polymer solids.

[0011] The present invention is also directed to a method for admixing a solid, water insoluble photo-initiator to an aqueous architectural composition comprising the steps of~ mixing the solid, water insoluble photo-initiator in a liquid, water dispersible photo-initiator until the solid, water insoluble photo-initiator is mixed to form a solution; and- mixing said solution in said aqueous architectural composition until said solution is dispersed in said aqueous architectural composition;- wherein preferably the solid, water insoluble and liquid, water dispersible photo-initiators are benzophenone derivatives,- wherein preferably the solid, water insoluble photo-initiator is not dissolved in acetone or another volatile solvent, and- wherein the mixing steps occurred at temperatures below a temperature of about 75°C or below about 50°C, or from about 20°C to about 25°C.

[6012] The present invention is further directed to an aqueous architectural composition comprising an aqueous architectural composition comprising: a polymeric latex resin, and an optional opacifying pigment to provide hiding, wherein a first solid, water insoluble benzophenone (BP) UV absorber, a second solid, water insoluble 4-methylbenzophenone (4MBP) UV absorber, and substantially no UV scavenger, preferably no UV scavenger, are added to the aqueous architectural composition to improve gloss retention, and wherein the BP and 4MBP UV absorbers are dissolved in a solvent, which preferably is acetone or Texanol, before being admixed to the architectural composition,wherein the BP UV absorber ranges from about 0.30 wt.% to about 0.75 wt.% of polymer solids, preferably from about 0,34 wt.% to about 0.625 wt.% of polymer solids, more preferably from about 0.40 wt.% to about 0.50 wt.% of polymer solids; and the 4MBP additive ranges from 0.30 wt.% to about 3 wt.% of polymer solids; preferably from about 0.30 wt.% to about 2.75 wt.% of polymer solids; more preferably from about 0.30 wt.% to about 2.50 wt.% of polymer solids or from about 0.30 wt.% to about 2.0 wt.% of polymer solids.

[0013] The present invention is further directed to an aqueous architectural composition comprising: a polymeric latex resin, and an optional opacifying pigment to provide hiding, wherein a first solid, water insoluble benzophenone (BP) UV absorber, a second solid, water insoluble 4-methylbenzophenone (4MBP) UV absorber, and substantially no UV scavenger, preferably no UV scavenger, are added to the aqueous architectural composition to improve gloss retention, and wherein the BP and 4MBP UV absorbers are combined and added to the architectural composition in a liquid state, wherein the combined BP and 4MBP can be from about 0.75 wt.% to about 6.0 wt.%, preferably about 1.0 wt.% to about 5.5 wt.%, more preferably from about 1.25% to about 5.25 wt.%, and more preferably from about 1.5 wt.% to about 5.0 wt.%.BRIEFd e s ON OF THE DR AWINGS

[0014] In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

[0015] Figure 1 is a bar graph showing the relative gloss retention between a group of paints with a liquid, w'ater dispersible UV absorber and a group of paints with a liquid, water dispersible UV absorber and a HALS;

[0016] Figure 2 is a line or X-Y graph showing the gloss readings of paints with a liquid, water dispersible UV absorber and a UV scavenger in an accelerated weathered test;

[0017] Figure 3 is a line or X-Y graph showing the gloss readings of paints with a solid, water insoluble UV absorber dissolved in a liquid, water dispersible UV absorber and a UV scavenger in an accelerated weathered test;

[0018] Figure 4 is a line or X-Y graph similar to Figure 3 at lower levels of additives, and with some of the solid, water insoluble UV absorber dissolved in acetone, and

[0019] Figure 5 shows the chemical structures of benzophenone and benzophenone derivatives.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The embodiments of the present invention are directed to architectural composition s, including but not limited to exterior paints and stains, that have improved gloss retention.

[0021] An embodiment of the present invention is directed to adding water dispersible photo- initiators) as UV absorber(s) alone or preferably with a UV scavenger, such as hindered amine light stabilizers (HALS), to architectural compositions, including but not limited to exterior paints and stains, to improve the architectural composition’s gloss retention.

[0022] The present inventors have discovered liquid water dispersible photo-initiator(s), such as water dispersible BP derivatives, that when added to architectural compositions along with a HALS without premixing with a solvent or without relying on elevated temperatures improves the gloss retention of the architectural compositions, particularly exterior paints, and stains. Such improvement is not known heretofore in the art. The suitable water dispersible BP derivative photo-in itiator(s) discussed herein are water insoluble and are in a liquid state when added to paints and stains. The water dispersible BP derivative photoinitiators are dispersed as droplets and are well distributed throughout the water. Without being bound to any particular theory, it is believed that the liquid BP derivatives are attracted to the latex particles conform to the free energy argument.

[0023] The suitable water dispersible BP derivative photo-initiators comprise, but not limited to, 2-methylbenzophenone (2MB P). 2MBP is insoluble in water, and is available in a liquid form. As used herein, BP derivatives means that the photo-initiators have chemical structures that are similar to that of BP. Preferably, BP derivatives have chemical structures that includes or incorporates the BP structure with additional moiety(-ies) or substituents). When 2MBP and a HALS are admixed to paints or stains, these additives improve the gloss retention of the paints or stains, as shown below by experiments.

[0024] Another embodiment of the present invention is directed to a novel composition and a novel method of adding solid, water insoluble photo-initiator(s) to an architectural composition without having to pre-mix the solid, water insoluble photo-initiator with a volatile solvent, such as acetone or coalescent aid or without adding the solid, water insoluble photo-initiator(s) to an architectural composition / polymer resin at an elevated temperature. In this embodiment, the solid, water insoluble photo-initiator, e.g., a solid BP derivative, is dissolved in a water dispersible photo-initiator, e.g., a water dispersible BP derivative, before being admixed to an architectural composition with or without HALS.

[0025] The present inventors have also discovered that some solid, water insoluble BP derivative photo-initiators are soluble in liquid, water dispersible BP derivative photoinitiators. Certain solid, water insoluble BP derivatives, such as 4-methylbenzophenone (4MBP), are soluble in 2MBP in a wide range of ratios. The solution of 2-MBP and 4-MBP can be directly added to and mixed with architectural compositions. When 2-MBP / 4-MBP and a HALS are added to paints and stains, these additives improve the gloss retention of paints and stains, as shown below by experiments.

[0026] Photo-initiators are molecules that when subjected to UV radiation produce chemical species, e.g., free radicals, that can initiate polymerization. These photo-initiators are used to polymerize UV -cured polymer resins. As discussed above, photo-initiators are also used as an additive to paints and stains, preferably exterior paints and stains, as UV absorbers to minimize the adverse effects of UV on exterior paint films and to improve gloss retention. Since being added to the paints and stains after the polymerization of the polymer resin, photo-initiators, such as BP and its derivatives, are not used to initiate polymerization, but is used for the generation of radicals after absorbing ultraviolet light and adsorbing electromagnetic radiation in certain visible range. As used herein, photo-initiators are utilized to absorb UV rays and some electromagnetic radiation in the visible range, and not as initiators for polymerization.

[0027] 2MBP has a similar structure as BP and 4MBP but with different physical properties, i.e., water insoluble / water dispersible versus water insoluble / water non-dispersible. 2MBP is a liquid at room temperature (RT at 20-25 °C) and BP and 4MBP are solid at RT. BP has a melting point around 47.8-51 °C, and 4MB P has a melting point at about 59.5°C. 2MBP has a melting point at about -18°C. Their structures are shown in Figure 5. 4MBP and 2MBP incorporate the BP chemical structure plus a methyl group (CH3) attached to one of thephenyl rings at different positions. On 4MBP, the methyl group is at the para position on the phenyl ring, and on 2MBP, the methyl group is at the ortho position.

[0028] The experiments below show improved gloss retention of exterior paints and stains by the preferred embodiments of the present invention. TINUVIN™ 292 is used as the HALS; however, as discussed below', the present invention is not limited to TINUVIN™ 292. Other HALS’s and UV scavengers can be used.

[0029] The paints and stains discussed in the experiments described herein utilized the same polymer resin as the resin binder. This polymer resin binder latex is polymerized as shown in Example I .The latex has a pH of 8,56 and 51.05% solid. The particle size is about 143.5 nm and the minimum film forming temperature is about -1.0 °C (ISO 2115)

[0030] The polymer resin binder latex from Example 1 is used in all paint samples tested herein. Example 2. Representative Faint ExampleMix for 20 minutes with good agitation.

[0031] Paint samples of Example 2 with UV absorber and / or UV scavenger additives added are tested according to the accelerated QU V-A tests, conducted according to the ASTM G154. The QUV-A test reproduces the damage caused by sunlight, including UV rays, rain and dew. This test can reproduce the exterior environmental damage that occur over monthsin a shorter period of days or weeks. The QUV-A test exposes the sample paint films to alternating cycles of UV light and moisture at elevated temperatures. Natural sunlight is simulated with fluorescent UV lamps in the UV-A range, , i.e., 295 nm to 365 nm range of the electromagnetic spectrum, Dew and rain are simulated with condensing humidity and / or water spray. This test is widely used as a weathering tester.

[0832] The gloss or the gloss finish of a dried paint surface indicates the level of shininess or glass-likeness of the surface. The level of gloss ranges from flat / matte to high gloss. The gloss of a surface can be described as the reflection of light from the surface that is independent of color. To measure gloss, a single beam of light is deflected off the surface at a particular angle into a receptor and discussed in commonly owned U.S. patent No.11,155,117, which is incorporated herein by reference in its entirety. The receptor gauges the intensity of that light in gloss units. The equipment is standardized with specially produced, polished, glass or ceramic tiles. ASTM method D 523 provides the procedures for performing this gloss test.

[0033] ASTM method D 523 uses 60° angle for comparing surface glosses and to determine whether other angles such as 20° and 85°are warranted. The 20° angle is used when the surface sample has a 60° gloss value greater than 70 gloss units, and the 85° is used if the 60° gloss value is less than 30 gloss units. The angle is measured from a vertical axis, e.g., a 60° angle is measured from the vertical line or the 0°line, and the 60° angle is 30° above the surface being tested.

[0034] Commonly, the term sheen is used to describe the low angle gloss, e.g., 85° from vertical or 5° above the surface to be measured. The 85° angle is preferred in measuring low gloss coatings, and is generally a more accurate indicator of the transition between flat and eggshell, Steep angles, such as 20°, are more often used with a high gloss surface such as automotive coatings.

[0035] The Master Paint Institute (MPI) categorizes the gloss finishes of paints as follows:TABLE 1. The Reflectivity of Paints with Different Gloss at Different AnglesHigher gloss values indicate shinier surfaces.

[0036] In the experiments conducted for the present invention and discussed herein, Comparative Examples are paint exampies with no or only one of UV absorber and UV scavenger, but not both. Inventive Examples are paint examples that contain both UV absorber and UV scavenger or paint examples that contain at least two (2) UV absorbers.

[9037] Examples 3-8 are Comparative Examples where either 2-MBP or Tinuvin 292 / HALS is added to 450g of paint Example 2 and mixed with good agitation for 10-20 minutes to ensure complete mixture. In Inventive Examples 9-12 an amount of 2MBP was added to 450g of paint in Example 2. The paint was mixed with good agitation for 20 minutes. Then the Tinuvin 292 / HALS was added and the paint was again mixed with good agitation for 10- 20 minutes.

[0938] The percentages of UV absorbers and UV scavengers reported in the Tables of this document are weight percentages based on polymer solids for all the examples discussed herein, including paint examples that have lower initial gloss readings (Examples 13, 14 and 15) and paint examples that are 3-base (Examples 34A-C and 35-39). The other paint examples are 1-base paints. 1-base, 2~base, 3-base and 4~base paints differ in the amount of opacifying pigments contained therein. Paint bases are discussed in commonly owned U.S. patent No. 9,994,722, which is incorporated herein by reference in its entirety. In the rows below'’ the 3 header row's, the left column shows the exterior exposure time (hours) to simulated environment in the acceierated QUV-A testing, and the remaining columns show the corresponding gloss reading at 60° at the indicated time. Unless otherwise indicated, all gloss readings are at 60°.TABLE 2.

[0039] In Table 2, the initial gloss readings of Examples 3-12 show that these Examples have gloss reading in the middle range of the semi-gloss finish. The gloss readings at 0 hours represent the initial gloss reading. Table 3 is similar to Table 2, except that the % of gloss loss are reported instead of the gloss readings.TABLE 3.

[0040] Examples 5-8 have progressively more of the UV absorber. Examples 9-12 have the same amounts of UV absorber, respectively, and 1.90% of the UV scavenger. Figure 1 is a bar graph comparing these Examples to each other. With both UV absorber and UV scavenger, the loss of gloss is between about 10% to 15%, With only UV absorber, the loss of gloss is between about 23% and 31%, which is comparable to the control Example 3.Example 4, which only has UV scavenger, is better than control Example 3. Figure 2 is a line or X-Y graph showing the gloss readings throughout the experiments showing that the group of lines from Examples 9-12 consistently exhibit less loss of gloss.

[0941] Another set of examples of paints, made with the polymer binder resin of Example 1 and lower initial gloss, i.e., in the satin finish, is shown below.TABLE 4 TABLE 5The results show that at satin finishes, Inventive Examples 14 and 15 both outperformedComparative Example 13. The Persoz hardness values also show that the increases in hardness for Inventive Examples 14 and 15 are higher than that of Comparative Example 13, indicating that a certain amount of cross-linking occurred in the Inventive Examples.

[0042] In the embodiment where the water dispersible UV absorber and HALS are added directly to the paints, a. the liquid, water dispersible UV absorber ranges from about 0,50 to about 11.0 wt.% based on polymer solids, preferably from about 1 .0 to about 10.5 wt.% based on polymer solids, preferably from about 1.25 to about 10.25 wt.% based on polymer solids, preferably from about 1.5 to about 10.0 wt.% based on polymer solids; and b. the HALS ranges from about 0.1 to about 3,0 wt.% based on polymer solids, preferably from about 1.0 to about 2.5 wt.% based on polymer solids, preferably from about 1.50 to about 2.0 wt.% based on polymer solids.The range of HALS also relies on the experiments discussed below, where a wider range of HALS was used,

[0043] In another embodiment of the present invention, an insoluble, solid UV absorber, such as BP or 4MBP, is dissolved in a liquid, water dispersible UV absorber, such as 2MBP, before being added to the paints or stains. The paint formulations for these experiments are substantially the same as - preferably the same as - the paint in Example 2. BP and 4MBP are readily dissolved in 2MBP, and this solution is added to the paints and mixed thoroughly. Then, the UV scavenger is added and thoroughly mixed. The order of mixing can be reversed and the present invention is not limited to any mixing order. The present inventors have discovered that up to 1 part of 4MBP (e.g., 0.001 part - Ipart) can be dissolved in 1 part of 2MBP at room temperature (RT at 20-25 °C), and up to 1 -1.3 parts of 4MBP can be dissolved in 1 part of 2MBP at elevated temperatures (e.g., emulsion polymerization temperature range) below about 75CC or below' about 50oC.

[0044] Experiments were conducted with water insoluble UV absorber and w'ater dispersible UV absorber together with HALS admixed into the paints, BP and 4MBP were the water insoluble UV absorbers. In the first experiment, 4MBP is mixed with 2MBP to form a solution to be added to the paints. Thereafter, the UV scavenger Tinuvin 292 is added. Tables 6 and 7 show the results from this experiment.TABLE 6TABLE 7

[0045] As shown in Tables 6 and 7 and in Figure 3, at relatively higher levels of UV scavenger (1.5%-3.0% of polymer solids), relatively high levels of water dispersible UV absorber (3.2%-5% of polymer solids), and water insoluble UV absorber (0.45%-3.2% of polymer solids), the gloss readings increased for significant parts of the QUV-A testing. The gloss increased up to 1,250 hours for all inventive samples and up to 2,347 hours for Example 17. This represents an unexpected result for this embodiment of the present invention. All inventive examples have significantly lower gloss loss than the comparative Example 16 after 2,500 hours. This first set of experiments shows the synergistic results of including liquid, water dispersible UV absorber, water insoluble UV absorber and HALS added to architectural compositions, such as exterior paints and stains. Figure 3 is a line or X-Y graph of the gloss readings throughout the experiments shown in Tables 6 and 7.

[8046] In another experiment, iower levels of UV scavenger and liquid, water dispersible and solid, water insoluble UV absorbers were used. Dissolving the solid, insoluble UV absorber in liquid, water dispersible UV absorber was tested against dissolving solid, insoluble UV absorber in acetone. Examples 22, 24 and 26 were repeated as Examples 23, 25 and 27, respectively, except that in the latter 4MBP was first dissolved in acetone and then mixed into the paints with 2MBP and Tinuvin 292. In the former, 4MBP was mixed with 2MBP and then mixed into the paints with Tinuvin 292.

[0047] Table 8 and 9 show the results from this experiment.TABLE 8TABLE 9| Example [ 21 |

[0048] The results, shown in Figure 4, show that mixing the water insoluble UV absorber in acetone is comparable to mixing the water insoluble UV absorber in liquid, water dispersibleUV absorber. The results also show that the gloss retentions are comparable, and are better than Comparative Example 21.[0(149] The results also show that with lower levels of UV scavenger (0.11%-1.27% of polymer solids), and relatively low levels of liquid, water dispersible UV absorber (0.36%- 4.25% of polymer solids), the loss of gloss increased. It is also shown that Examples 22 and 23 with higher UV scavenger and UV absorber the gloss retention are best, and are comparable to those in Tables 6 and 7, but without the increased gloss. Examples 26-27 show improved gloss retention when compared to Comparative Example 21. Examples 24-25, which have the lowest combined additives - i.e., 0.5 wt.% of polymer solids - have slightly improved gloss retention when compared to Comparative Example 21, and are within the scope of the present invention. Examples 24-25 represent the lower end of the ranges of the additives in accordance with this embodiment of the present invention.[00501 other experiments BP was used instead of 4MBP at the substantially the same weight percentages. Water insoluble BP was mixed with 2MBP to form a solution and water insoluble BP was also dissolved first in acetone before being admixed with UV scavenger- HALS into paints, as shown in Tables §A and 9A.

[0951] Tables 6A and 7A show the results with higher weight % within the first 500 hours in QUV-A testing.TABLE 6ATABLE 7 A

[8052] Table SA and 9A show the results with lower levels of BP, some of which are first dissolved in acetone.TABLE SATABLE 9A

[0053] While gloss and sheen readings at 20° and 85° are recorded for the experiments with BP as the water insoluble UV absorber, these readings are at sharper angles. Gloss readings at 60° are used to compare to control Example 41 , and to the other experiments disclosed herein.

[0054] These experiments show that BP dissolved in 2MBP or in acetone at all the weight percentage levels performed better than the control even at the low 0.04 wt.% and 0.12 wt.% within the first 500 hours. Unexpectedly, these experiments do not show an increase in gloss, as shown with the 4MBP dissolved in 2MBP and acetone.

[8055] Additionally, the co-inventors have determined by experimentation that both BP and 4MBP can be dissolved together in 2MBP and then added to the architectural composition.

[0056] For the embodiment where the water insoluble UV absorber(s) is / are dissolved in the liquid, water dispersible UV absorber: a. the insoluble UV absorber ranges from about 0.03 to about 4.0 wt.% based on polymer solids, preferably from about 0.10 to about 3.5 wt.% based on polymer solids, preferably from about 0.40 to about 3.0 wt.% based on polymer solids;b. the liquid, water dispersible UV absorber ranges from about 0.25 to about 6.5 wt.% based on polymer solids, preferably from about 0.30 to about 5.5 wt.% based on polymer solids, preferably from about 0.35 to about 4.0 wt.% based on polymer solids, preferably from about 1.25 to about 3.5 wt.% based on polymer solids; and c. the HALS ranges from about 0,10 to about 4.0 wt.% based on polymer solids, preferably from about 0.25 to about 3.5 wt.% based on polymer solids, preferably from about 0.40 to about 3.0 wt.% based on polymer solids.The combined water insoluble UV absorber, liquid, water dispersible UV absorber and HALS range from 0.5 wt.% based on polymer solids to the sum of the highest values of all three additives. While the sum of the lowest values of three addi tives discussed in this paragraph is less than 0.5 wt.%, one or more values may be increased so that their sum is at least 0.5 wt.%.

[0057] The present inventors have determined that other solid, water insoluble photoinitiators are also soluble in 2MBP and therefore can be dissolved in 2MBP before being added to the paints and stains.Table 10

[0058] In yet another embodiment of the present invention, two photo-initiator additives are added, preferably without a HALS, to an architectural composition, such as exterior paints, to reduce gloss loss or improve gloss retention. Preferably, one photo-initiator is BP and the other is a BP derivative, preferably 4MBP. In one experiment, the BP and 4MBP are first dissolved in acetone or Texanol solvent before being added to exterior paints.

[0059] Table 10Table 11

[0060] Table 12Table 13

[0061] The data in Tables 10-13 shows that at low levels of BP and less than about 3.0 wt.% of polymer solids of 4MB P the inventive paints show' better gloss retention than Comparative Example 28A and 34A. High levels of 4MBP alone in Comparative Examples 28B and 34B do not necessarily sho w impro ved gloss retention. High levels of BP alone in Comparative Examples 28C and 34C do show improved gloss retention.

[0062] For the embodiment where at least two water insoluble UV absorbers, such as BP and 4MBP, are dissolved and added to the architectural composition:(a) the BP additive ranges from about 0.30 wt.% to about 0.75 wt.% of polymer solids, preferably from about 0.34 wt.% to about 0.625 wt.% of polymer solids, more preferably from about 0.40 wt.% to about 0,50 wt.% of polymer solids;(b) the 4MBP additive ranges from 0.30 wt.% to about. 3 wt.% of polymer solids; preferably from about 0.30 wt.% to about 2.75 wt.% of polymer solids; more preferably from about 0.30 wt.% to about 2.50 wt.% of polymer solids or from about 0.30 wt.% to about 2.0 wt.% of polymer solids; and(c) there is substantially no HALS or other UV scavenger; preferably there is no HALS or other UV scavenger. “Substantially no” means less than 0.05 wt.% of polymer solids.

[0063] In another experiment, a liquid form of BP and 4MB P, commercially available as Omnirad® 81 from IGM Group BV, is added directly to exterior paints. This Omnirad® 81 liquid additive comprises BP and 4MBP with each from 40 wt.% to less than 60 wt.% according to the manufacturer iGM Resins’ Safety Data Sheet, and the remaining minor component(s) are not disclosed by the manufacturer. It has been reported that BP and 4MBP make up about 98 wt.% Omirad® 81.TABLE 14 TABLE 15

[0064] This data also shows that at lower amounts of BP and 4MBP , the paint has improved gloss retention. That is also true for higher amounts of BP and 4MBP. For this embodiment, where BP and 4MBP in a liquid state are added to the architectural composition, the combined BP and 4MBP can be from about 0.75 wt.% to about 6.0 wt.%, due to its performance shown in Table 14, preferably about 1.0 wt.% to about 5.5 wt.%, more preferably from about 1.25% to about 5.25 wt.%, and more preferably from about 1.5 wt.% to about 5.0 wt.%.

[8065] Suitable HALS include those based on the 2,2,6,6-tetramethylpiperidine chemical structure. Exemplary HALS include bis (1, 2, 2, 6, 6-pentamethyl-4-piperidyl) sebacate and methyl 1, 2, 2, 6, 6- pentamethyl-4-piperidyl sebacate.

[0066] Additional suitable HALS’s are disclosed in published international patent application No. WO 2010 / 027487, which are reproduced here: “CYASORB UV-3346 (Cytec Industries, CAS# 90751 - 07-8), CYASORB UV-3529 (Cytec Industries, CAS# 193098-40-7), CYASORB UV- 3641 (Cytec Industries, CAS# 106917-30-0), CYASORB UV-3581 (Cytec Industries, CAS# 79720-19-7), CYASORB UV-3853 (Cytec Industries, CAS# 167078-06-0), CYASORB UV-3853 S (Cytec Industries, CAS# 24860-22-8), TINUVIN 622 (Ciba Specialty Chemicals, CAS# 65447-77-0), TINUVIN 770 (Ciba Specialty Chemicals, CAS# 52829-07-9), TINUVIN 144 (Ciba Specialty Chemicals, CAS# 63843-89-0), TINUVIN 123 (Ciba Specialty Chemicals, CAS# 129757-67-1), CHIMASSORB 944 (Ciba Specialty Chemicals, CAS# 71878-19-8), CHIMASSORB 119 (Ciba Specialty' Chemicals, CAS# 106990-43-6), CHIMASSORB 2020 (Ciba Specialty Chemicals, CAS# 192268-64-7), LOWILITE 76 (Great Lakes Chemical Corp., CAS# 41556-26- 7), LOWILITE 62 (Great Lakes Chemical Corp., CAS# 65447-77-0), LOWILITE 94 (Great Lakes Chemical Corp., CAS# 71878-19-8), UVASIL 299LM (Great Lakes Chemical Corp., CAS# 182635-99-0), UVASIL 299HM (Great Lakes Chemical Corp., CAS# 182635-99-0), Dastib 1082 (Vocht a.s, CAS# 131290-28-3), UVINUL 4049H (BASF Corp, CAS# 109423-00-9), UVINUL 4050H (BASF Corp, CAS# 124172-53-8), UVINUL 5050H (BASF Corp, CAS# 199237- 39-3), MARK LA 57 (Asahi Denka Co, Ltd., CAS# 64022-61-3), MARK LA 52 (Asahi Denka Co, Ltd, CAS# 91788-83-9), MARK LA 62 (Asahi Denka Co, Ltd, CAS# 107119- 91-5), MARK LA 67 (Asahi Denka Co, Ltd, C AS# 100631 -43-4), MARK LA 63 (Asahi Denka Co, Ltd. Co, Ltd. Co, CAS# 115055-30-6), MARK LA 68 (Asahi Denka Co, Ltd, CAS# 100631-44-5), HOSTAVIN N 20 (Clariant Corp, CAS# 95078-42-5), HOSTAVIN N 24 (Clariant Corp, CAS# 85099-51 -1, CAS# 85099-50-9), HOSTAVIN N 30 (Clariant Corp., CAS# 78276-66-1), DIACETAM-5 (GTPZAB Gigiena Truda, USSR, CAS# 76505- 58-3), UVASORB-HA 88 (3 V Sigma, CAS# 136504-96-6), GOODRITE UV-3034 (BF Goodrich Chemical Co, CAS# 71029-16- 8), GOODRITE UV-3150 (BF Goodrich Chemical Co, CAS# 96204-36-3), GOODRITE UV-3159 (BF Goodrich Chemical Co, CAS# 130277- 45-1), SANDUVOR 3050 (Clariant Corp, CAS# 85099-51-0), SANDUVOR PR-31 (Clariant Corp, CAS# 147783-69-5), UV CHECK AM806 (Ferro Corp, CAS# 1546.36-12-1), SUMISORB TM-061 (Sumitomo Chemical Company, CAS# 84214- 94-8), SUMISORB LS-060 (Sumitomo Chemical Company, CAS# 99473-08-2), UVASIL 299 LM (Great Lakes Chemical Corp., CAS# 164648-93-5), UVASIL 299 HM (Great Lakes Chemical Corp., CAS# 164648-93-5), and NYLOSTAB S-EED (Clariant Corp., CAS# 42774-15-2).”

[0067] Suitable emulsion latex particles include but are not limited to acrylic, vinyl, vinylacrylic or styrene-acrylic polymers or copolymers. The latex particles coalesce and / or crosslink to form a paint film on a substrate. Latexes made principally from acrylic monomers are preferred for the present invention, as illustrated in the Examples herewithin. Exemplary, non-limiting monomers suitable to form the emulsion latex particles for the present invention are described below.

[0068] Generally, any (meth)acrylic monomers can be used in the present invention. Suitable (meth)acryiic monomers include, but are not limited to methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, iso-octyl (meth)acryiate, lauryl (meth)acrylate, 2- ethylhexyl (meth)acrylate, stearyl (meth)acrylate, isobomyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-ethyoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acry1ate, 2- hydroxybutyl (meth)acrylate, dimethylamino ethyl (meth)acrylate, di ethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylamide, alkyl (meth)acrylic acids, such as methyl (meth)acrylate acids, (meth)acrylic acids, wet adhesion monomers, such as N-(2- methacryloyloxyethyl)ethylene urea, and multifunctional monomers such as divinyl benzene, diacrylates, for crosslinking functions etc., acrylic acids, ionic acrylate salts, alkacrylic acids, ionic alkacryiate salts, haloacrylic acids, ionic baloacrylate salts, acrylamides, alkacrylamides, monoalkyl acrylamides, monoalkyl alkacry lam ides, alkyl acrylates, alkyl alkacrylates, acrylonitrile, alkacry lonitriles, dialkyl acrylamides, dialkyl alkacrylamides, hydroxyalkyl acrylates, hydroxyalkyl alkacrylates, only partially esterified acrylate esters of alkylene glycols, only partially esterified acrylate esters of non-polymeric polyhydroxy compounds like glycerol, only partially esterified acrylate esters of polymeric polyhydroxy compounds, itaconic acid, itaconic mono and di-esters, and combinations thereof. The preferred alkyl (meth)acrylate monomers are methyl methacrylate and butyl acrylate, and as stated above acid monomers are preferably omitted or included at very' low levels.

[0669] Preferred monomers containing aromatic groups are styrene and a-methylstyrene. Other suitable monomers containing aromatic groups include, but are not limited to, 2,4- diphenyl-4~methyl-l -pentene, 2,4-dimethylstyrene, 2,4,6-trimethylstyrene, 2, 3, 4, 5, 6-pentafluorostyrene, (vinylbenzyl)trimethylammonium chloride, 2,6-dichlorostyrene, 2- fluorostyrene, 2-isopropenylaniline, 3(trifluoromethyl)styrene, 3-fluorostyrene, a- methylstyrene, 3-vinylbenzoic acid, 4-vinylbenzyl chloride, a-bromostyrene, 9- vinylanthracene, and combinations thereof.

[0070] Preferred monomers containing primary amide groups are (meth)acrylamides. Suitable monomers containing amide groups include, but are not limited to, N- vinylformamide, or any vinyl amide, N,N-dimethyl(meth)acryIamide, N-(l,l-dimethyl-3- oxobutyl)(meth)acrylamide, N-(hydroxymethyl)(meth)acrylamide, N-(3- methoxypropyl)(meth)acrylamide, N-(butoxymethyl)(meth)acrylamide, N-- (isobutoxymethyl)acryl(meth)acrylamide, N- [tris(hydroxymethyl)methyl]acryl(meth)acrylamide, 7-[4- (trifluoromethyl)coumarin](nieth)acrylamide, 3 -(3 -fluorophenyl)-2"propenamide, 3 -(4- methylphenyl)(meth)aciylamide, 'N-(tert-butyl)(metb)acry]amide, and combinations thereof. These monomers can be polymerized with acrylic monomers, listed above. General formula for vinyi(form)amides are:and (meth)acrylamides:where R1 and R2 can be -H, -CH3, -CH2CH3, and other substituted organic functional groups and R3 can be -H, an alkyl or an aryl.

[0071] In one embodiment, styrene monomers, such as styrene, methylstyrene, chlorostyrene, methoxystyrene and the like, are preferably co-polymerized with (meth)acrylamide monomers.

[0072] In one embodiment, the aqueous latex polymer may also comprise vinyl monomers. Monomers of this type suitable for use in accordance with the present invention include any compounds having vinyl functionality, i.e., -CH=CH2group. Preferably, the vinyl monomers are selected from the group consisting of vinyl esters, vinyl aromatic hydrocarbons, vinyl aliphatic hydrocarbons, vinyl alkyl ethers and mixtures thereof.

[0073] Suitable vinyl monomers include vinyl esters, such as, for example, vinyl acetate, vinyl propionate, vinyl laurate, vinyl pivalate, vinyl nonanoate, vinyl decanoate, vinyl neodecanoate, vinyl butyrates, vinyl caproate, vinyl benzoates, vinyl isopropyl acetates and similar vinyl esters; nitrile monomers, such (meth)acrylonitrile and the like; vinyl aromatic hydrocarbons, such as, for example, styrene, methyl styrenes and similar lower alkyl styrenes, chlorostyrene, vinyl toluene, vinyl naphthalene and divinyl benzene; vinyl aliphatic hydrocarbon monomers, such as, for example, vinyl chloride and vinylidene chloride as well as alpha olefins such as, for example, ethylene, propylene, isobutylene, as well as conjugated dienes such as 1,3-butadiene, methyl-2-butadiene, 1,3-piperyiene, 2,3-dimethyl butadiene, isoprene, cyclohexene, cyclopentadiene, and dicyclopentadiene; and vinyl alkyl ethers, such as, for example, methyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, and isobutyl vinyl ether.

[0874] Additives including surfactants, initiators, chaser solutions, biocides, rheological modifiers, etc. can be added to the polymerization process.

[0875] Surfactants are described in “Additives Reference Guide” by J.V. Koleske, R. Springate and D. Brezinski at pp. 83-88 (2013), and these pages are incorporated herein in their entirety. The following discussion of surfactants are based on Koleske et al.

[0076] Nonionic surfactants usually refer to polyoxyethylene derivatives although other surfactants are included in this category. They are usually prepared by the addition reaction of ethylene oxide to hydrophobic compounds that contain one or more active hydrogen atoms. Examples of such hydrophobic compounds are fatty alcohols, alkylphenols, fatty acids, faty amines, alkanolamines, fatty mercaptans, fatty amines and certain polyols. The polyols can include oxypropylene polyols, polyesters, and the like. These surfactants do notcarry a charge nor do they dissociate. Their surface-active character comes from the oxyethylene portion of the molecule. Both the nature of the hydrophobe and the length of the oxyethylene chain have an effect on the surface-active character.

[0077] Overall, these groups are weakly hydrophilic in comparison to the hydrophobic portion of the molecule. Also present in many non ionic surfactants are weak ester and amide linkages. Nonionic surfactants are generally compatible with ionic surfactants. For example, many nonionic surfactants function well with anionic surfactants. In such combinations, they impart good freeze-thaw stability to aqueous systems and are less deleterious to mechanical properties than the ionic compounds. Nonylphenol ethoxylate (NPE) is a typical example of such surfactants. Other examples are: octylphenol ethoxylates (OPE), secondary alcohol ethoxylates, trimethyl nonanol ethoxylates (TMN), specialty alkoxylates, and amine ethoxylates. In emulsion polymerization, alkyl ether sulfates are one of the major surfactants necessary to provide for the stabilization of micelles. Traditionally, these sulfates have been based on alkylphenol ethoxylates (APEOs). Typically, emulsion polymerization uses two types of surfactants - one nonionic and the other anionic. Each provides separate stabilization mechanisms for the micelles, but the combination provides better stabilization, especially as temperature increases. The nonionic surfactants bestow' a steric separation between micelle groups, while anionic surfactants yield a charged repulsion between the micelles. Nonionic surfactants generally perform well over a range of pH values, and they will usually foam less than anionic and cationic surfactants. However, nonionic surfactants may not lower the surface tension as well as anionic or cationic surfactants in complex coating formulations. There are nonionic polymeric fluorochemical surfactants that provide low surface tensions in organic coating systems. The lower the surface tension, the more effectively a coating wets, levels and spreads. Consequently, these are excellent wetting, leveling and flow' control agents for a variety of waterborne, solvent bome and high solids coatings systems. Most of the fluoro-surfactants are soluble and compatible with most polymers and continue to be active throughout the drying or curing process. When used in waterborne systems, they tend to reduce the aqueous / organic interfacial tension and remain surface active in the organic portion of the polymer system. There is also an anionic fluoro-surfactant on the market based on ammonium salt, which is soluble in water.

[0078] Anionic surfactants carry' a negative charge on the hydrophi lic portion of the molecule. They are usually phosphates, sulfates and sulfonates. These surfactants may or may not contain an oxyethylene chain in their structure. Examples of anionic surfactants aresulfosuccinates, dioctyl sulfosuccinate (DOSS), polyether sulfates, polyether sulfonates, polyetber phosphates, sodium lauryl sulfate and phosphate ester-modified alcoholethoxylates.

[0079] Surface-active phosphate esters are a class of anionic surfactants prepared by the reaction of alcohols with an activated phosphoric acid derivative - including phosphoric acid anhydrides and acid chlorides. Typically, phosphate ester commercial products are composed of a m ixture of monoester, diester, free-phosphoric acid and free alcohol used in its preparation. The property of the final phosphate ester product is primarily defined by the starting alcohol used as well as on the composition of the four different species. Conversely, the property of the final phosphate product can be tailor-m ade by altering the alcohol used in the preparation as well as controlling the ratio of the four different components present in the final product. Phosphate ester surfactants are made in the free-acid form, but can also be neutralized to the salt form using any base including sodium hydroxide, potassium hydroxide, ammonium hydroxide or any organic amine.

[0080] Typically, the phosphate ester surfactants are added into the formulation during paint manufacture - added either in the grind or letdown depending upon the formulation. These additives have also been tested as post-paint formulation additives and have exhibited comparable properties. It has been speculated, and is the focus of a number of investigations, that use of the phosphate ester surfactant before the paint formulation stage -- use of phosphate esters in emulsion polymerization as well as post polymerization stabilizer or additive in pigment dispersion - should only benefit the final property of the paint as well as reduce the detrimental effects of additional surfactants into the paint system.

[0081] Cationic surfactants carry a positive charge and quaternary’ ammonium compounds are the most common cationic surfactants. Compounds such as alkyl trimethyl ammonium chloride typify these surfactants.

[0082] The Hydrophilic Lipophilic Balance, HLB, system is a numbering system for rating the relative hydrophilic nature of a surfactant. The system is based on an arbitrary numerical scale where zero is assigned to a surfactant that is overwhelmingly hydrophobic and 20 is assigned to a surfactant that is overwhelmingly hydrophilic. The number assigned to the surfactant represents a measure of the balance between its hydrophilic and hydrophobic strengths. A surfactan t with an HLB of 10 has an equal balance of oil-loving and waterloving groups.

[0083] Examples of initiators and chaser solutions useful in the polymerization process may include, but are not limited to, ammonium persulfate, sodium persulfate, azo initiators such as azow’obutyronitrile, redox systems such as sodium hydroxymethanesulfinate (sodium formaldehyde sulfoxylate; reducer) and t-butyl-hydroperoxide (oxidizer), and the like, and combinations thereof, typically in an aqueous solution. Either or both of these components can optionally contain an additional surfactant and / or a pH adjuster, if desired to stabilize the emulsion.

[0084] Examples of pH adjusters useful in the polymerization process may include, but are not limited to, ammonium hydroxide, sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, ammonia, amines such as trimethylamine, triethylamine, dimethylaminoethanol, diethylaminoethanol, AMP-95 and the like, and combinations thereof. In certain cases, compounds that qualify as pH adjusters can be added for purposes other than adjusting pH, e.g., emulsion stabilization, and yet are still characterized herein as pH adjusters.

[0085] Polymer molecular weight control agents are designed to control (usually to limit) the molecular weight of a propagating polymer. While polymer molecular weight control agents may include things like radiation, they are typically molecules added to the polymerization mixture. Examples of polymer molecular weight control agents include, but are not limited to, chain transfer agents (CTAs), e.g., alkyl mercapto-esters such as isooctyl mercaptopropionate, alkyl mercaptans, and the like, and combinations thereof. Chain transfer agents typically operate as polymer molecular weight control agent molecules, for example, by catalytically or consumptively terminating a propagating polymer chain in a way that also initiates a newly propagating polymer chain. In this way, the amount of chain transfer ageni(s) can be tailored to reduce the target polymer molecular weight in a set polymerization system, or alternately, in combination with calculation of the amount of initiator, can be calculated to target a particular average polymer molecular weight (e.g,, within a given range) of a polymerization system.

[0086] Titanium dioxide is commonly used as opacifying pigment as shown in Examples 2A and 2B. Zinc oxide can also be used as opacifying pigment. Extender pigments are commonly added to paints and include aluminum silicate and diatomaceous earth as shown in Examples 2 A and 2B. Other suitable extender pigments include, but are not limited to, calcium carbonate, magnesium silicate, aluminum potassium silicate, nepheline syenite, and arediscussed in commonly owned U.S. patent No. 11,518,893, which is incorporated herein by reference in its entirety.

[0087] Unless indicated otherwise, all percentages are weight percentages, except for percentages of changes in gloss readings.

[0088] As used herein, architectural composition(s) includes interior and exterior paints, and stains, and specifically excludes traffic paints and asphalt compositions since these paints are not used in residential and commercial structures.

[0089] While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the objectives stated above, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention.

Claims

We claim:

1. An aqueous architectural composition comprising: a polymeric latex resin, an optional opacifying pigment, a water dispersible, liquid UV absorber, wherein the water dispersible, liquid UV absorber comprises 2-methylbenzophenone a UV scavenger, wherein the UV scavenger comprises a hindered amine light stabilizer (HALS); wherein the water dispersible UV absorber ranges from about 0.50 to about 11.0 wt.% based on polymer solids, preferably from about i.O to about 10.5 wt.% based on polymer solids, preferably from about 1.25 to about 10.25 wt.% based on polymer solids, preferably from about 1.5 to about 10.0 wt.% based on polymer solids: and wherein the HALS ranges from about 0.1 to about 3.0 wt.% based on polymer solids, preferably from about 1.0 to about 2.5 wt.% based on polymer solids, preferably from about 1 .50 to about 2.0 wt.% based on polymer solids.

2. An aqueous architectural composition comprising: a polymeric latex resin, an optional opacifying pigment, a solid, water insoluble UV absorber, wherein the water insoluble UV absorber comprises either 4-methylbenzophenone or benzophenone, or both, a liquid, water dispersible UV absorber, wherein the liquid, water dispersible UV absorber comprises 2-methylbenzophenone, wherein the solid, water insoluble UV absorber is dissolved in the liquid, water dispersible UV absorber, a UV scavenger, wherein the UV scavenger comprises a hindered amine light stabilizer (HALS); wherein the solid, water insoluble UV absorber ranges from about 0.03 to about 4.0 wt.% based on polymer solids, preferably from about 0.10 to about 3.5 wt.% based on polymer solids, preferably from about 0.40 to about 3.0 wt.% based on polymer solids; wherein the liquid, water dispersible UV absorber ranges from about 0.25 to about 6.5 wt.% based on polymer solids, preferably from about 0.30 to about 5.5 wt.% based onpolymer solids, preferably from about 0.35 to about 4.0 wt.% based on polymer solids, preferably from about 1,25 to about 3.5 wt.% based on polymer solids; wherein the HALS ranges from about 0.10 to about 4.0 wt.% based on polymer solids, preferably from about 0.25 to about 3.5 wt.% based on polymer solids, preferably from about 0.40 to about 3.0 wt.% based on polymer solids, and wherein a combined insoluble UV absorber, liquid, water dispersible UV absorber and HALS range from 0.5 wt.% based on polymer solids to a sum of the highest values of the combined insoluble LTV absorber, liquid, water dispersible UV absorber and HALS based on polymer solids.

3. A method for admixing a solid, water insoluble photo-initiator to an aqueous architectural composition comprising the steps of mixing the solid, water insoluble photo-initiator in a liquid, water dispersible photoinitiator until the solid, water insoluble photo-initiator is mixed to form a solution; and mixing said solution in said aqueous architectural composition until said solution is dispersed in said aqueous architectural composition; wherein preferably the solid, 'water insoluble and liquid, water dispersible photoinitiators are benzophenone derivatives, wherein preferably the solid, water insoluble photo-initiator is not dissolved in acetone or another volatile solvent, and wherein the mixing steps occurred at. temperatures below a temperature of about 75 °C or below about 50°C, or from about 20°C to about 25°C.

4. An aqueous architectural composition comprising: a polymeric latex resin, and an optional opacifying pigment to provide hiding, wherein a first solid, water insoluble benzophenone (BP) UV absorber, a second solid, water insoluble 4-methylbenzophenone (4MBP) UV absorber, and substantially no UV scavenger, preferably no UV scavenger, are added to the aqueous architectural composition to improve gloss retention, and whereinthe BP and 4MBP UV absorbers are dissolved in a solvent, which preferably is acetone or Texanol, or in a liquid, water dispersible UV absorber, which preferably is 2- methylbenzophenone, before being admixed to the architectural composition, wherein the BP UV absorber ranges from about 0.30 wt.% to about 0.75 wt.% of polymer solids, preferably from about 0.34 wt.% to about 0.625 wt.% of polymer solids, more preferably from about 0.40 wt.% to about 0.50 wt.% of polymer solids; and the 4MBP additive ranges from 0.30 wt.% to about 3 wt.% of polymer soiids; preferably from about 0.30 wt.% to about 2.75 wt.% of polymer soiids; more preferably from about 0,30 wt.% to about 2.50 wt.% of polymer solids or from about 0.30 wt.% to about 2.0 wt.% of polymer solids.

5. An aqueous architectural composition comprising: a polymeric latex resin, and an optional opacifying pigment to provide hiding, wherein a first solid, water insoluble benzophenone (BP) UV absorber, a second solid, water insoluble 4-methylbenzophenone (4MBP) UV absorber, and substantially no UV scavenger, preferably no UV scavenger, are added to the aqueous architectural composition to improve gloss retention, and wherein the BP and 4MBP UV absorbers are combined and added to the architectural composition in a liquid state, wherein the combined BP and 4MBP can be from about 0.75 wt.% to about 6.0 wt.%, preferably about 1.0 wt.% to about 5.5 wt.%, more preferably from about 1.25% to about 5.25 wt.%, and more preferably from about 1.5 wt.% to about 5.0 wt.%.

6. The aqueous architectural composition of claim 1 or 2, wherein the HALS is based on the 2,2,6,6-tetramethylpiperidine chemical structure.

7. The aqueous architectural composition of claim I, 2 or 4, wherein the polymeric latex resin is polymerized from (meth)acrylate monomers, except for an optional wet adhesion monomer.

8. The aqueous architectural composition of claims 1, 2 or 4, wherein the aqueous architectural composition is or comprises a paint, preferably an exterior paint.

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