PROSPERSE 704 Acrylic Polyurethane Polymer For Industrial Coatings

Transcription

1 Technical Data Sheet PROSPERSE 704 Acrylic Polyurethane Polymer For Industrial Coatings Description PROSPERSE 704 is an aqueous acrylic polyurethane polymer based on DESIGNED DIFFUSION Resin Technology, which offers a new paradigm in waterborne polymer film formation. It is an ambient self-crosslinking polymer and is manufactured without the use of NMP (N-methylpyrrolidone). PROSPERSE 704 offers rapid early hardness development, improved block, print and dirt pickup resistance, and excellent warmth when applied to wood. These properties make it well suited for factory and field applied, waterborne interior wood finishes. It is especially recommended as a sealer and topcoat in clear coatings and offers excellent clarity and warmth over both dark and light woods. PROSPERSE 704 can facilitate formulation of high performance, lower VOC coatings. Formulations based on PROSPERSE 704 offer films with excellent appearance, early hardness, and early sandability. Its self-crosslinking chemistry is responsible for the development of exceptional chemical and stain resistance. Features and Benefits Typical Physical Properties Low VOC capability Self-crosslinking Fast hardness development Fast release of coalescent from films Quick drying and early sandability Early block and print resistance Excellent water resistance Excellent chemical and solvent resistance Manufactured without the use of APEO surfactant and NMP solvent These properties are typical but do not constitute specifications. Property Appearance Solids, % 39.5 ph 7.6 Viscosity (Brookfield, #3/30rpm) Typical Values White milky liquid 50 cp MFFT 11 C Solvent content (on total) VOC (g/l, as supplied) 58 Approximately 1.9% PROGLYDE DMM Glycol Diether Page 1 of 9 PROSPERSE 704 Acrylic Polyurethane Polymer / Dow Coating Materials 05/2012, Rev. 0

2 Potential Applications Introduction to DESIGNED DIFFUSION Resin Technology Kitchen cabinets Residential and office furniture DIY interior wood coatings Interior joinery General wood finishing Mechanism and Benefits of DESIGNED DIFFUSION Resin Technology Once film formation has occurred, coalescents and co-solvents employed in formulations are no longer needed in the film, and it is desirable for them to leave the dry coating film to enhance properties such as hardness. Some slow coalescents (e.g., Texanol) will remain in acrylic coating films for many weeks or longer. Acrylic/urethane polymers based on DESIGNED DIFFUSION Resin Technology provide a novel mechanism for the faster release of volatile materials, such as coalescents and co-solvents, from the drying film. The result is a dry film which provides faster hardness development and other film properties that rely on hardness such as block, print, mar and dirt pickup resistance. The technology depends on the presence of two polymer phases. The major or dominant phase is a hydrophobic, hard acrylic polymer the hardness development works best with an acrylic having a T g > 25 C. The second, minor phase is a soft polyurethane polymer, which in the wet state is more hydrophilic than the acrylic due to its swollen, hydroplasticized state. In the wet state of the formulated polymer, the coalescent partitions mainly to the more hydrophobic acrylic phase, where it aids in lowering the minimum film formation temperature (MFFT). This partitioning of coalescent has been demonstrated through computer modeling studies and experimentally using NMR techniques. After application of the coating, water evaporates and polymer particles will begin to deform as film formation proceeds, as shown pictorially in Figure 1. When most of the water has left the film, the polyurethane phase changes from being to hydrophilic to hydrophobic this acts as a trigger for the coalescent to diffuse from the acrylic phase to the polyurethane phase. It is known that small molecules, such as coalescent molecules, will diffuse more rapidly through a soft polymer phase, and thus the coalescent will diffuse out of the film via the polyurethane phase more rapidly than it would if the acrylic phase were by itself. One requirement of the mechanism shown in Figure 1 is that the polyurethane phase must form a continuous network through which the coalescent can diffuse. The amount of polyurethane needed to form this percolation network depends on the relative particle sizes of the polyurethane dispersion and acrylic latex employed and the geometry of particle packing, but in general a minimum of about 20% by weight of the total polymer is required. The film formation mechanism of the DESIGNED DIFFUSION Resin Technology facilitates faster coalescent release from a drying film, and impacts properties such as early hardness development, and block, print, mar and dirt pickup resistance. The faster coalescent release also presents the possibility for lowering the TVOC (total VOC) of a factory-applied wood coating, which is the amount of VOC released from a coated part after it has been dried for a certain period of time. Early water resistance can be improved by removing hygroscopic materials such as hydrophilic coalescents and co-solvents from the drying film before the dry film comes into contact with water. The presence of a polyurethane phase also tends to improve toughness, as measured by pencil hardness, compared to an all-acrylic composition. Page 2 of 9 PROSPERSE 704 Acrylic Polyurethane Polymer / Dow Coating Materials 05/2012, Rev. 0

3 Introduction to DESIGNED DIFFUSION Resin Technology Con t. Another key feature of PROSPERSE 704 Acrylic Polyurethane Polymer is its ability to self-crosslink at ambient temperatures and still maintain true one-component package stability. The functional groups present in the resin will crosslink via both oxidative and photolytic curing mechanisms. Formulations based on PROSPERSE 704 Resin will begin to crosslink as soon as they are applied, and may require about 2 to 4 weeks until some properties have reached their maximum performance level. The crosslinking offers enhancements to properties such as dirt pickup resistance, chemical and solvent resistance, and durability. Because PROSPERSE 704 Acrylic Polyurethane Polymer combines both hard acrylic and soft polyurethane phases, it displays lower coalescent demand than the corresponding acrylic phase by itself. This manifests itself in the ability to be formulated at lower VOC, while giving a coating that has better hardness development a combination that is sought after in a variety of applications. In addition, PROSPERSE 704 has a lower polyurethane content than most acrylic/urethane hybrids, and can therefore offer a cost advantage. Figure 1. Mechanism of accelerated coalescent release with DESIGNED DIFFUSION Resin Technology. hard, high T g acrylic soft PUD coalescent molecule water evaporation coalescent transfer to soft polyurethane phase particle deformation polymer diffusion accelerated evaporation Performance Data The typical performance of PROSPERSE 704 Acrylic Polyurethane Polymer is demonstrated in the following Tables and plots. A plot of Konig hardness development vs time is shown in Figure 2, comparing PROSPERSE 704 to a commercial acrylic polymer (Tg = 43 C). The commercial polymer is designed for use over wood and is comparable to the hard acrylic phase in PROSPERSE 704. Both polymers are in the same clear formulations with 20% of the various coalescents on total binder solids. Hydrophobic and hydrophilic coalescents were used, as well as fast- and slow-evaporating coalescents, and in each case PROSPERSE 704 shows the more rapid hardness development expected with the DESIGNED DIFFUSION Technology. The benefit is not present if a non-volatile plasticizer (e.g., dibutylphthalate) is used, as the coalescent must have volatility in order to leave the film. Pencil hardness is usually slightly better for the acrylic/urethane typically pencil hardness is improved by one to two pencil units due to the faster coalescent release and inherent toughness of the polyurethane phase. Block and print resistance are also notably improved. Page 3 of 9 PROSPERSE 704 Acrylic Polyurethane Polymer / Dow Coating Materials 05/2012, Rev. 0

4 Performance Data Con t. Results of block resistance testing on clear films is shown in Table 1, comparing PROSPERSE 704 with the commercial acrylic at equivalent levels of coalescent (20% on polymer solids). Other properties like chemical resistance and flexibility remain largely unchanged by the presence of the polyurethane phase. Water resistance is generally improved by the more rapid release of coalescent from the hybrid film. Figure 2. Comparison of hardness development for PROSPERSE 704 Acrylic Polyurethane Polymer and a hard acrylic latex in clear formulations with different coalescent packages Konig hardness (sec) Time (days) Hard acrylic / Butyl CELLOSOLVE Glycol Ether Hard acrylic / DOWANOL DPnB Glycol Ether Hard acrylic / Texanol Hard acrylic / Dibutylphthalate PROSPERSE 704 / Butyl CELLOSOLVE PROSPERSE 704 / DOWANOL DPnB PROSPERSE 704 / Texanol PROSPERSE 704 / Dibutylphthalate Table 1. Block resistance of clear formulations. 1 day dry 7 day dry 24 hr at RT 30 min at 60 C 24 hr at RT 30 min at 60 C PROSPERSE 704 / Texanol ester alcohol Hard acrylic / Texanol PROSPERSE 704 / Butyl CELLOSOLVE Hard acrylic / Butyl CELLOSOLVE Note: Formulations contained equal levels of the noted coalescent (20% on total polymer solids). Block resistance rated on a 1 to 10 scale, 10 = best. Coatings were dried for either 1 or 7 days before being subjected to the room temperature or 60 C block test. Page 4 of 9 PROSPERSE 704 Acrylic Polyurethane Polymer / Dow Coating Materials 05/2012, Rev. 0

5 Table 2 compares PROSPERSE 704 to the hard acrylic latex, which exhibits excellent performance in wood coatings. Both binders were formulated into the same clear formulation (see Formulation 704-1). The coatings were tested in self-sealed coating systems over maple using test methods typical for wood furniture and general wood coatings. PROSPERSE 704 performed very well, and performed similarly to the hard acrylic in chemical resistance, adhesion and print resistance. Table 2. Evaluation of Clear Coatings for Furniture and General Wood Applications. Coating System PROSPERSE 707 Polymer Hard Acrylic Film Properties: Adhesion Pass Pass Print Resistance (1 day dry / 16 hr print) Chemical resistance (16 hr spots, rated 1 to 10, 10 = no effect) Water 9 8 Hot Coffee % Ethanol Cleaner 5 8 IPA 9 9 7% Ammonia 4 6 Red Ink 5 4 Grape Juice 10 9 PROSPERSE 704 can also be formulated into pigmented coatings, such as the gloss white topcoat detailed in Formulation The improved hardness development and related properties are also observed with the pigmented formulation. Table 3 compares coating performance of PROSPERSE 704 in Formulation to the hard acrylic described above. The hard acrylic was formulated at a similar VOC level in the same formulation. Included in the comparison are two commercial waterborne gloss trim paints. Table 3 lists some of the other properties for the pigmented coatings, and shows distinct benefits in block and print resistance for the DESIGNED DIFFUSION Technology. Formulating Guidelines PROSPERSE 704 Acrylic Polyurethane Polymer can be formulated with common additives available for waterborne coatings. However, because of the crosslinking technology used in this emulsion, additives that contain or release formaldehyde are not recommended in combination with PROSPERSE 704. In addition, application of coatings based on PROSPERSE 704 should not be made to substrates that release formaldehyde. The use of such materials or substrates may cause slight yellowing of the film and degradation of film properties. Coalescents Depending on drying conditions and application methods, the selection of a coalescent is critical to obtaining optimum properties for coatings based on PROSPERSE 704. The starting-point formulations contain a blend of coalescent and plasticizers. Plasticizer, in small quantities, imparts flexibility to the film without detracting from block resistance properties. A blend of water-miscible and water-immiscible coalescents is recommended for industrial applications. Butyl CELLOSOLVE Glycol Ether evaporates quickly and improves the flow of PROSPERSE 704, while DOWANOL DPnB Glycol Ether remains slightly longer in the polymer phase and facilitates good film formation. Page 5 of 9 PROSPERSE 704 Acrylic Polyurethane Polymer / Dow Coating Materials 05/2012, Rev. 0

6 Formulating Guidelines Con t. Care should be taken in adding coalescents to the letdown. For wood coatings, formulating at lower ph is often beneficial for grain raising, but can compromise stability. Add coalescents slowly to avoid the formation of grit or gel, particularly when at lower ph values (below ph 8.0). Mar Aids The addition of Michem Emulsion and Tego Glide 410 offers excellent mar and slip resistance. Levels of 5 6% Michem Emulsion and 0.5 1% of Tego Glide 410 on polymer solids are recommended. Flatting Aids Silica flatting aids, such as Syloid 7000, are recommended for flatting coatings based on PROSPERSE 704 Acrylic polyurethane Polymer. Formaldehyde-containing flatting aids should not be used. Defoamers Tego Foamex 805 is an effective defoamer for formulations containing PROSPERSE 704 and should not cause any surface defects. One percent total defoamer (as supplied) on the total weight of the formulation is recommended. Care should be exercised with high levels of silicone defoamers, as they can cause craters in the film. Table 3. Evaluation of gloss white pigmented coatings for wood coatings applications Coating System PROSPERSE 704 Hard Acrylic Commercial WB trim paint #1 Commercial WB trim paint #2 Gloss ( 60 ) Pencil Hardness (2 wk) HB HB 3B 2B Konig Hardness (2 wk, sec) Block Resistance 1 day dry 24 hr at RT min at 60 C day dry 24 hr at RT min at 60 C Print Resistance 1 day dry 24 hr at RT min at 60 C day dry 24 hr at RT min at 60 C Wetting Aids The addition of an additive such as Surfynol 104DPM offers good surface wetting and reduces the tendency for formulations based on PROSPERSE 704 Resin to crater or picture frame. Page 6 of 9 PROSPERSE 704 Acrylic Polyurethane Polymer / Dow Coating Materials 05/2012, Rev. 0

7 Viscosity Control ACRYSOL RM-825 or RM-8W Rheology Modifier can be used in formulations to control viscosity for conventional, air-assisted, and airless spray applications, curtain coater and roller applications. These rheology modifiers are associative HEUR types and, as such, the addition of surfactants will change the rheology profile of the formulation. Preservatives and Mildewcides Formaldehyde or formaldehyde-releasing preservatives will adversely affect the performance of paints based on PROSPERSE 704 Acrylic Polyurethane Polymer and are not recommended for use with this polymer. When selecting a preservative, check with the raw material supplier to ensure that formaldehyde or formaldehyde-releasers are not present. Formulation Clear gloss wood topcoat formulation based on PROSPERSE 704 Polymer Material Name Pounds Gallons PROSPERSE Premix DOWANOL PnB Glycol Ether DOWANOL DPM DOWANOL DPnB RHOPLEX WP-1 Plasticizer Water Premix Subtotal Tego Foamex 805 defoamer Tego Glide 410 additive Surfynol 104DPM additive Michem Emulsion wax Water Totals Levels without Additives: Volume Solids: 28.4% Weight Solids: 31.5% Density (lb/gal): 8.69 VOC (g/l): 144 Levels with Additives: Volume Solids: 30.5% Weight Solids: 33.5% Page 7 of 9 PROSPERSE 704 Acrylic Polyurethane Polymer / Dow Coating Materials 05/2012, Rev. 0

8 Formulation Gloss white topcoat formulation based on PROSPERSE 704 Polymer Material Name Pounds Gallons PROSPERSE Ammonia (15%) Tego Foamex 1488 defoamer Ti-Pure R-746 slurry TiO Texanol ester alcohol Propylene Glycol Water ACRYSOL RM-2020NPR Rheology Modifier ACRYSOL RM-8W Totals Levels without Additives: PVC 19.1% Volume Solids: 33.1% Weight Solids: 45.7% Density (lb/gal): VOC (g/l): 149 Levels with Additives: Volume Solids: 33.5% Weight Solids: 46.2% Page 8 of 9 PROSPERSE 704 Acrylic Polyurethane Polymer / Dow Coating Materials 05/2012, Rev. 0

9 Handling Precautions Storage Disposal Considerations Before using this product, consult the Material Safety Data Sheet (MSDS)/Safety Data Sheet (SDS) for details on product hazards, recommended handling precautions and product storage. Store products in tightly closed original containers at temperatures recommended on the product label. Dispose in accordance with all local, state (provincial) and federal regulations. Empty containers may contain hazardous residues. This material and its container must be disposed in a safe and legal manner. It is the user's responsibility to verify that treatment and disposal procedures comply with local, state (provincial) and federal regulations. Contact your Dow Coating Materials Technical Representative for more information. Chemical Registration Product Stewardship Customer Notice Many countries require the registration of chemicals, either imported or produced locally, prior to their commercial use. Violation of these regulations may lead to substantial penalties imposed upon the user, the importer or manufacturer, and/or cessation of supply. It is in your interests to ensure that all chemicals used by you are registered. The Dow Chemical Company does not supply unregistered products unless permitted under limited sampling procedures as a precursor to registration. Dow has a fundamental concern for all who make, distribute, and use its products, and for the environment in which we live. This concern is the basis for our product stewardship philosophy by which we assess the safety, health, and environmental information on our products and then take appropriate steps to protect employee and public health and our environment. The success of our product stewardship program rests with each and every individual involved with Dow products - from the initial concept and research, to manufacture, use, sale, disposal, and recycle of each product. Dow strongly encourages its customers to review both their manufacturing processes and their applications of Dow products from the standpoint of human health and environmental quality to ensure that Dow products are not used in ways for which they are not intended or tested. Dow personnel are available to answer your questions and to provide reasonable technical support. Dow product literature, including safety data sheets, should be consulted prior to use of Dow products. Current safety data sheets are available from Dow. Contact: North America: Latin America: (+55) Europe: (+800) Asia-Pacific: (+800) Notice: No freedom from infringement of any patent owned by Dow or others is to be inferred. Because use conditions and applicable laws may differ from one location to another and may change with time, Customer is responsible for determining whether products and the information in this document are appropriate for Customer's use and for ensuring that Customer's workplace and disposal practices are in compliance with applicable laws and other government enactments. The product shown in this literature may not be available for sale and/or available in all geographies where Dow is represented. The claims made may not have been approved for use in all countries. Dow assumes no obligation or liability for the information in this document. References to Dow or the Company mean the Dow legal entity selling the products to Customer unless otherwise expressly noted. NO WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED. Page 9 of 9 PROSPERSE 704 Acrylic Polyurethane Polymer / Dow Coating Materials 05/2012, Rev. 0