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Dispercoll C® ® Disper coll C P oly chlor opr ene Latices for Adhesiv e Applications: P r oper ties and Compounding Guide Helping make our customers’ vision a reality. Bayer MaterialScience, where VisionWorks Dispercoll Solids Content (%) Viscosity (cps) pH Particle size (nm) Crystallization tendency Emulsifier C-74 58 80 13 160 Medium Anionic C-84 55 110 13 160 Strong Anionic C LS 2372H 58 100 13 160 Low Anionic Properties Dispercoll C-74. is a strong crystallizing polymer. Dispercoll C polychloroprene latices have the same chemical structure as Baypren polycloroprenes. Dispercoll C LS 2372H has found its niche in formulations which are designed to have high tack and also the ability to be repositioned. Polychloroprene latices have been sold under the Dispercoll C trade name for adhesive applications for over 25 years. Dispercoll C-84 is a strong crystallizing grade which has high tensile strength. Dispercoll C-74 is a medium crystallizing grade with high heat resistance. One can see from the film data that this gives relatively high elongation and long open time. Other applications for Dispercoll C polychloroprene latices are footwear. mill work and DIY. Dispercoll C latices have been found to be an excellent alternative to solvent based adhesives that used non-flammable solvents.Dispercoll® C Polychloroprene Latices for Adhesive Applications: Properties and Compounding Guide Introduction Bayer has long history with polychloroprene rubber for adhesive applications. Dispercoll C-74 is being used in bonding high pressure laminate to particle board which requires good heat resistance along with a contact bond life of more than one hour. The differences in the softening points between these three products reflect different molecular weights. Each product's unique properties lend themselves to different applications. Applications Bayer Material Science offers three different grades of Dispercoll C polychloroprene latices. This results in high tensile strength and a shorter open time. C-84 and LS 2372H polychloroprene latices are alkaline colloidal dispersions of 2-chlorobutadiene produced by emulsion polymerization. Dispercoll C latices can be used to formulate adhesives which meet many of the VOC regulations and also greatly reduce fire hazards that have been associated with flammable solvents. Dispercoll C-84. Dispercoll C LS 2372H is a low crystallizing grade with high degree of tackiness and long contact bond life. Film Properties Dispercoll Tensile Strength (psi) Elongation at break (%) 100% Modulus Softening Point (°C) Contact Bond Life Pass 1 hour 30 minutes 72 hours 1 C-74 500 1000 120 82 C-84 2900 760 580 61 C LS 2372H 65 1000 60 50 . on the other hand. Dispercoll C latices provide a safe and environmental friendly alternative to solvent based adhesives. so they have the same good weathering properties and chemical resistance. Dispercoll C-74 is a medium crystallizing polymer. Dispercoll C-84 has become the product of choice for applications such as bonding polyurethane foam which needs high wet bond strength. The advantages of using water borne systems have pushed their growth rate above solvent based polychloroprene adhesives. Dispercoll C LS 2372H is a low crystalline with very long open time and lower tensile strength. In Bayer's early screening studies it was observed that a tackifier level of 20 phr did not change the peel strength of the formulation. Levels of 35 and 50 phr gave a good bond strength and contact bond life values. but usually shorten open time. Because each commercial resin dispersion has its own surface active ingredients that may or may not be compatible with a particular grade of Dispercoll C latex. The difference in contact bond life can be seen in the following graph.such as resins. 2 . coumarone-indene resins. the emulsion stability and adhesive properties of each formulation should be evaluated. but average heat resistance. Rosin ester types are known for their good tack characteristics. thickeners and stabilizers . or hydrocarbon resins. antioxidants. and improve wet stability and aging properties. A resin level of 65 phr decreased the peel strength because of a loss of adhesion between the two adhesive films. Terpene phenolic resins are known to give improved heat resistance.to modify adhesion. rosin esters. Resins Resins improve the adhesion of Dispercoll C based adhesives to many substrates and affect their open times.ADHESIVE FORMULATING CONTACT CEMENTS Dispercoll C Latices are normally compounded with other ingredients . The tackifying resins most widely used in water based formulating are dispersions of terpene phenolic resins. Examples of Commercial Resin Dispersions which are compatible with Dispercoll C products. zinc oxide. rheological behavior. Supplier Schenectady DRT Eastman Name HRJ 11112 Dermulsene TR501 Dermulsene TR602 Tacolyn 5002 Tacolyn 5003 Tacolyn 3185 Tacolyn 3400 Aquatac 6085 Aquatac E5375 Resin Type Terpene phenolic Terpene phenolic Terpene phenolic Aromatic modified hydrocarbon Aromatic modified hydrocarbon Rosin ester Rosin ester Rosin ester Rosin ester Arizona The following chart shows the effect of different types of resins on open time. Bayer has also introduced four grades of Dispercoll S silica dioxide sols which enhance the performance of Dispercoll C polychloroprene latices. Several resin manufacturers supply terpene phenolic and rosin ester resins in dispersion form. Those resins that are sensitive to oxidation. Antioxidants Antioxidants are primarily used in polychloroprene based adhesives to protect the tackifying resin that is used in compounding. Rohm & Haas manufactures Acrysol RM-8W associative thickener. Surfactants can also be used to improve the mechanical stability during high shear conditions. The most common is to increase the viscosity of the finished adhesive to provide enough sag resistance to prevent the wet film from flowing off the substrates. Thickeners can also aid in the suspension of pigments. from readily settling out. Examples of compatible surfactants. Associative thickeners based on acrylates and urethanes are a class of thickeners which are now widely used.g. It provides stable viscosity and uniform texture. Both anionic and nonionic surfactants have been to be useful with Dispercoll C products. is recommended to help prevent this oxidative attack. polyacrylates. The types of thickeners which have commonly been used for water based adhesives are polyvinyl alcohols. 3 . which has been found to work well with Dispercoll C-74 and C-84 based formulations. It should be noted that too much of an emulsifying agent can have a negative effect on the properties of the adhesive by decreasing moisture resistance or interfering with the contact properties. e. fillers or metal oxides such as zinc oxide. Typically 2 to 5 parts by weight of Zinkoxyd Aktiv. precipitated zinc oxide. on a hundred parts of polychloroprene polymer are added to the formulation as an aqueous dispersion. which are heavier than the latex.Acid Scavenger Zinc oxide serves as a stabilizer by neutralizing the minute amounts of hydrogen chloride which are split off from the polymer as it ages. rosin esters and coumarone-indene. Both zinc oxide and antioxidants are commercially available as dispersions. alginates and methylcellulose. such as Vulkanox BKF. Elevated temperatures also cause the evolution of hydrogen chloride and destabilization of the latex emulsion. Surfactant Daxad 11KLS Igepal CO 710 Igepal CA 630 Rhodaplex CO 433 Triton X-100 Emulvin W Type Anionic Nonionic Nonionic Anionic Nonionic Nonionic Supplier GEO Specialty Chemicals Stepan Chemicals Stepan Chemicals Rhodia Surfactants Dow Chemical Lanxess Thickeners Thickeners are used in water based systems for a variety of reasons. Higher viscosity will prevent additives. Nonionic surfactants can be used to reduce the tendency to coagulate at low pH values. A hindered phenolic antioxidant. The following table details dispersions from two different suppliers. may become brittle due to aging and cause bond failure. Manufacturer AkroChem Akron Dispersions ZnO Dispersion W-9804 Bostex 422 Antioxidant Dispersion W-9924 Bostex 346 Surfactants Surfactants can be used to improve the compatibility of the various compounding ingredients. 0 4. These silica sols are produced from a sodium silicate dispersion through a process that removes the sodium to a minute level and then builds the molecular weight that is best for long term dispersion stability. They can be used to modify viscosity.Dispercoll S Bayer has developed a series of Silica Sols. which are nano-particulate sized silica dioxide dispersed in an aqueous medium. HIGH INITIAL BOND STRENGTH C-84/TR 85/S3030 FORMULATION INGREDIENTS Wet Weight Solids Content Dispercoll C-84 Desmulsene TR 602 Dispercoll S 3030 ZnO2 Dispersion Latex Resin SiO2 HCl scavenger 100. contact bond life. softening point. act as an acid scavenger and provide wet bond strength. FORMULATIONS The following suggested starting formulations are design to address specific performance requirements. The smaller the particle size Dispercoll S grades show higher viscosities. Each grade of Dispercoll S gives a different viscosity at a defined quantity.0 55% 55% 30% 33% 50% Vulkanox Dispersion Antioxidant Open time Softening point Viscosity 4 hours 69°C 3640 cps 4 . Dispercoll S S 5005 S 4510 S 4020 S 3030 Solids % 50 45 40 30 Density (g/cm3) 1. experiments indicate that levels in the 5 to 15 phl range are better for adhesion to the substrates. These products have been found to improve the adhesive properties of Dispercoll C polychloroprene latices. However in bonding high pressure laminate to particle board. Each adhesive manufacture should test this and adjust according to their needs.0 15.208 Surface (m2/g) 50 100 200 300 Diameter (nm) 55 30 15 9 Formulas with high levels of Dispercoll S 3030 silica sol have shown very good wet bond strength. These levels still show improvements in contact bond life and heat resistance.295 1.34 1.39 1. These formulations are based on Dispercoll C/resin combinations known to be compatible.0 2.0 10. 0 2.0 4.HIGH HEAT RESISTANCE FORMULATION INGREDIENTS Wet Weight Solids Content Dispercoll C-74 Emulvin W Latex Surfactant 100.0 2.0 55% 55% 30% 33% 50% Open time Softening point Viscosity 7 hours 66°C 5100 cps 5 .0 10.0 4.0 15. Defoamer.0 30.0 58% 20% 43% 33% 50% Schenectady HRJ 11112 Tackifier ZnO2 HCl scavenger Vulkanox Dispersion Antioxidant 2.0 Optional Ingredients: Dispercoll S. Thickener LONG CONTACT BOND LIFE FORMULATION INGREDIENTS Wet Weight Solids Content Dispercoll C-84 VTAC 9001 Dispercoll S 3030 ZnO2 Dispersion Vulkanox Dispersion Latex Resin SiO2 HCl scavenger Antioxidant 100. 0 2.0 30.0 4.0 30. Thickener 6 .WET BONDING (Textile) FORMULATION Wet Weight Solids Content INGREDIENTS Dispercoll C-84 Dispercoll S 3030 ZnO2 Dispersion Vulkanox Dispersion Latex SiO2 HCl scavenger Antioxidant 100. Colorant LOW ENERGY SURFACES FORMULATION Wet Weight Solids Content INGREDIENTS Dispercoll C LS 2372H Emulvin W Tacolyn 3185 ZnO2 Dispersion Vulkanox Dispersion Latex Surfactant Tackifier HCl scavenger Antioxidant 100.0 2.0 4.0 2.0 58% 20% 55% 33% 50% Optional Ingredients: Defoamer.0 55% 30% 33% 50% Optional Ingredients: Defoamer. One of the technologies which has gained wide acceptance is the use of 2 component polychloroprene latex based adhesives.1-trichloroethane. The basic principle of a 2 component polychloroprene adhesive is the destabilization of the latex emulsion by a salt or weak acid. A typical fluid delivery ratio is 100 ml of adhesive to 10 ml of salt solution. upper foam Internal foam block foam for construction of box foam with adhesive Bonding of seating using 2K spray mix process with Dispercoll C 7 . Because the coagulation behavior of the polychloroprene is the key to the success of these adhesives the resin normally only added at a level of 20 to 30 parts on 100 latex. Salts like calcium chloride are dissolved into water at a 5% level. Differences in the solution concentration or utilized salt may vary the mix ratio. adhesives containing chlorinated solvents have historically been used. Sometimes wetting agents or defoamers are employed.FOAM TO FOAM BONDING 2-Component Adhesive For the bonding of foams in the manufacture of upholstered furniture and mattresses. Coagulation of the latex occurs in the aerosol phase before it hits the substrate. The utilization of this behavior for adhesives was made possible by the development of spray guns that delivers both the adhesive and salt solution simultaneously from separate delivery nozzles. Each pressure pot has its own pressure and delivery adjustments. Resins are added to modify tack. The effective utilization of this technology is dependent on the proper adjustment of the spray equipment. it became necessary to eliminate adhesives containing 1. With the introduction of regulations on the use of chlorinated solvents. The water that is present in the adhesive film is absorbed by the substrate and eventually evaporates over a period of time. Zinc oxide and antioxidants are added in disperse form to aid in the aging stability of the adhesive bond. Surfactants can be used to modify the mechanical stability of the adhesive. This principle has been used in the manufacture of latex gloves for many years. A two component foam adhesive contains the same ingredients as the typical water based polychloroprene adhesive. The spray gun atomizes both the adhesive and the salt into the spray zone. The type of resin dispersion will influence the heat resistance properties.1. Because the adhesive has been coagulated it has the necessary green strength to immediately bond the foam substrates together. The salt solution is placed in the second of two storage pots that a 2-component spray gun system contains. 2K FORMULATION FORMULATION INGREDIENTS Wet Weight Solids Content Dispercoll C-84 Emulvin W Dermulsene TR 602 ZnO2 Dispersion Vulkanox Dispersion Latex Surfactant Tackifier HCl scavenger Antioxidant 100. Salt Destabilization Normal CR Micelle CICICICI- Polymer CI- Polymer CI- CI- CICI- 8 .0 6. CaCl2 or Zn SO4) Mix ratio 10:1 Optional Ingredients: Defoamer The following figures show that the potassium counter ion associates with the soap used in the emulsion polymerization.0 2.0 55% 20% 50% 33% 50% Coagulation Agent: 5% solution of salt (e.g.0 30.0 2. When the latex is co-sprayed with a salt solution the counter ion is pulled away from the emulsion boundary and coagulation occurs. Also these types of systems tend to have shorter shelf lives because the natural downward pH drift of polychloroprenes will bring the adhesive closer to its coagulation point. Each ingredient that is added to the formulation can affect the emulsion stability. The following is a basic starting point formulation for a one component foam adhesive. To make the adhesive coagulate (break) upon spraying it is necessary to adjust the pH down to the point where the latex is barely stable. one component foam adhesives have become popular because it is not necessary to adjust mix ratios between the latex/resin “Part A” and the salt solution.0 30.1-Component Adhesive More recently. If the pH is adjusted too low the latex will coagulate in the container. This can be done with glycine or dilute hydrochloric acid.5) Discretional Ingredients: Surfactant and/or defoamer 9 . spraying will not cause coagulation. ONE COMPONENT FOAM ADHESIVE FORMULATION INGREDIENTS Wet Weight Solids Content Dispercoll C-84 Dermulsene TR 602 ZnO2Dispersion Vulkanox Dispersion Latex Tackifier HCl scavenger Antioxidant 100.0 to 9.0 55% 50% 33% 50% pH Adjusting Agent 18% Glycine solution (to pH of 9.0 2. If the pH is too high. The challenge of a 1-component formulation is to avoid coagulating the adhesive before it is sprayed.0 6. Low pH Destabilization Dispercoll C Micelle Polymer Polymer Storage conditions The pH value of Dispercoll C polychloroprene latices tends to drop during prolonged storage.5 to 12. On the left is represented a stable polychloroprene emulsion at a typical pH.0 in 4 weeks.5 the potassium counter-ion no longer closely associated with soap. Mixing Procedure Water-based systems are sensitive to being destabilized by different pH levels or emulsification systems. which can result in reduced stability. 10 . During compounding. The stability of the latices may be affected by the addition of compounding ingredients. The general rule for order of addition is to start with the largest amount and work to the smallest amount of ingredient. It is recommended that the pH value of the formulation be readjusted to at least 10. To provide the best pH stability a temperature around 23°C is best.0 units in 7 days. A 5% potassium hydroxide solution is recommended to increase pH. During the spraying process the latex is subjected to shear forces which cause it to coagulate into an adhesive film and be able to bond in a wet state. i. A temperature of 50°C has been shown to reduce the pH 1. For example a temperature of 30°C is likely to reduce the pH of Dispercoll C-84 from 12. The recommended storage temperature range is 5 to 25°C which will minimize the risk of pH change. In the figure below. The exceptions are materials that add stability and compatibility during the mixing process.The following figure gives a representation of the emulsion state of Dispercoll C. The compounding ingredients should be added to mixture slowly with sufficient shear to help ensure a homogenous blend. Temperatures above 25°C can be tolerated for short periods of time. Bayer states that the shelf life of the Dispercoll C latices is six months.e. The order and technique of addition can be critical to a formulation.5 (this is the pH at which there is no excess counter ion) to provide an acceptable shelf life. defoamers and surfactants. If surfactants are used in the formula. the right section shows that by lowering the pH to less than 9. the addition of resin dispersions normally will lower the pH of the finished adhesive. they are added to the latex prior to the other compounding ingredients. It is recommended that inventory be used on a first in first out basis to minimize the storage time of the latex. Thickening agents are normally added last. This reduction of the counter charge on the soap emulsion reduces the tendency for the emulsion particles to come in contact with each other and coagulate. Pittsburgh. PA. proper use. Information is available in several forms. 100 Bayer Road.g. (412) 777-2000. and handling. Safety and Plant Management Department. you must read and become familiar with the available information concerning its hazards. e. Before working with any product mentioned in this publication.. material safety data sheets and product labels. Consult your Bayer Representative acontact the Product Safety Manager within the Health. This cannot be overemphasized. Bayer Corporation. appropriate industrial hygiene and other safety precautions recommended by their manufacturers should be followed. 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