PRODUCT DATA ADIPRENE BLM 500 Water Emulsifiable/Dispersible Reactive Prepolymer ADIPRENE BLM 500 ADIPRENE BLM 500 is an MDI based urethane prepolymer with blocked isocyanate curing sites, which can be activated by heating. The blocked curing sites allow protracted storage of the polymer in the presence of moisture and active vulcanizing agents. Diamine-cured ADIPRENE BLM 500 yields vulcanizates having improved performance over common TDI based urethane materials. MDI is one of the most commonly used diisocyanates in industrial polyurethane applications. However, blocked MDI prepolymer and its application are very limited. Conventional MDI prepolymers generally contain more than 10% free MDI, due to the need of using excess amount of the diisocyanate in prepolymer preparation. Blocked prepolymers are highly viscous and gel-like in appearance. This is from the high tendency of crystallization of the blocked MDI. Urethane Prepolymers ADIPRENE BLM 500 is a novel blocked system based on low free isocyanate technology. With Chemtura s unique process, the residual MDI in the unblocked preoplymer is below 0.5%. The resulting blocked prepolymer has very good processing characteristics, such as low viscosity and melting point. Moreover, the widely used curative for conventional MDI prepolymer is 1,4 butanediol (BDO). Amine cured MDI polyurethanes are preferred for many demanding applications, expecially those requiring toughness and modulus retention at high temperature. Thus, blocked MDI prepolymers open to the opportunity to use amine curatives, for end-use properties not achieved by conventional MDI urethanes. Materials made from ADIPRENE BLM 500 have high tensile strength and high elongation, and especially have excellent tear strength. They are also low in viscous damping indicating low heat generation and more durability in dynamic applications. ADIPRENE BLM 500 is well suited as a vehicle for abrasion resistant coatings for fabric and rubber, and for solvent-resistant adhesives.
POLYMER PROPERTIES TABLE I Typical Properties of ADIPRENE BLM 500 Prepolymer Physical form... Viscous liquid Color... Light yellow to amber Isocyanate content, % Blocked... 4.17 4.63 Free... 0.2 max. Specific Gravity at 77 F (25 C)... 1.08 104 F (40 C)... 1.07 Viscosity (Brookfield), cps (Pa s) @ 122 F (50 C)... 12,000 35,000 (12 35) Raw prepolymer storage stability... Excellent at room temperature. ADIPRENE BLM 500 tends to freeze slowly when stored at 75 F (24 C) or below. It is unharmed by freezing and may be thawed by storing overnight at 125 F (52 C). After thawing, the liquid should be thoroughly mixed before it is used. Solubility... Soluble in most common solvents such as toluene, ethyl acetate, methyl ethyl ketone, and trichloroethylene. Solubility is limited in aliphatic solvents and alcohols. Handling Precautions... During heat cure, the blocking agent (methyl ethyl ketoxime), a volatile flammable liquid (b.p. above 302 F [150 C]), is evolved and provisions must be made for removal of this vapor. Trace amounts of diphenylmethane diisocyanate may also be released during cure. The blocking agent and diphenyl methane diisocyanate are irritants and harmful; exposure to and inhalation of their vapors should be avoided. Note: These data are presented to describe ADIPRENE BLM 500 and are not intended to serve as specifications. 2
TYPICAL VULCANIZATE PROPERTIES VULCANIZATE PROPERTIES Cured films of ADIPRENE BLM 500 urethane rubber are tough, highly extensible and have a high modulus. Table II shows the comparison of amine cured Adiprene BLM 500 and BL 16 (a TDI based prepolymer), and BDO cured conventional MDI prepolymer. Using Lonzacure MDEA and MDA, cured BLM 500 is tougher than BL 16/MDA, and much tougher than conventional MDI prepolymer/bdo, in terms of higher hardness, modulus and tear strength. Material from de-blocked/cured BLM 500 prepolymer also provides improved dynamic performance. Figure 1 demonstrates much lower damping at both low and high temperatures of material obtained with Adiprene BLM 500 (MDI based) vs. Adiprene BL 16 (TDI based.). TABLE II Property Comparison of Chain Extended BLM 500 vs. BL 16 and conventional MDI. B635* BLM 500 BL 16 Curative BDO ** MDEA *** MDA **** MDA Hardness, Shore A...89...95... 97...95 100% Modulus, psi...1100...2200... 2100...1650 300% Modulus, psi...----...3800... 2400...3650 Tensile, psi...6110...6350... 4250...5400 Elongation at break, %...390...410...600...455 Split Tear, pli...80...145... 210...130 * Vibrathane B 635 is a conventional non blocked MDI/PTMEG prepolymer. ** 1,4 Butanediol. *** 4,4 methylene-bis-2,6 diehylaniline **** 4,4 methylene dianiline Figure 1. BLM-500 vs BL-16; Damping Property Comparison 0.2 0.18 0.16 BLM-500/MDA BL-16/MDA 0.14 0.12 Tan Delta 0.1 0.08 0.06 0.04 0.02 0 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 Temperature, C 3
COMPOUNDING CURING SYSTEMS When unblocked by heat, the regenerated NCO groups in ADIPRENE BLM 500 react with any of the materials (containing active hydrogens) normally used as isocyanate reactants. Thus polyols and polyamines can be used as curatives. Polyols are quite slow in reacting with this prepolymer, so the most useful curatives appear to be aromatic diamines such as 4,4 methylene dianiline, and 4,4 methylene-bis-2,6 diethyl aniline. ADIPRENE BLM 500 is unblocked by heating at 212 to 266 F (100-130 C) for a period of time depending upon film thickness; a ten-mil (0.25mm) film of freshly mixed prepolymer and MDA is fully cured after one hour at 266 F (130 C). Aged blends will cure somewhat faster. Vulcanization of ADIPRENE BLM 500 in sections thicker than about 20 mils (0.50 mm) is impractical because of the difficulty of removing the blocking agent from thick films without blowing and subsequent porosity. COMPOUNDING Coatings and adhesives can be prepared in a wide viscosity range by diluting ADIPRENE BLM 500 with such solvents as toluene, xylene, ethyl acetate, or propylene glycol monomethyl ether acetate. Table III shows the viscosity/solvent level relationship of a blend of ADIPRENE BLM 500 and propylene glycol monomethyl ether acetate (PMA). TABLE III Viscosity of Solvent Solutions of ADIPRENE BLM 500 ADIPRENE BLM 500, 100 parts by weight Propylene glycol monomethyl ether acetate, phr Viscosity at 104 F (40 C), cps (Pa s) 0... 70,000 (70) 20... 3,000 (3.0) 40... 650 (0.65) 60... 250 (0.25) A typical solvent-diluted composition is shown in Table IV. This composition can be prepared as follows: mix ADIPRENE BLM 500 and propylene glycol monomethyl ether acetate at 104 F (40 C); melt the MDA at 212 F (100 C) and add to the ADIRENE BLM 500 solution with continuous stirring. MDA may also be added as a solution in solvent. 4
SOLVENT INFORMATION TABLE IV Solvent Diluted Composition Parts by weight: ADIPRENE BLM 500... 100 PMA (Propylene Glycol Monomethyl Ether Acetate)... 60 Methylene dianiline... 10 A substrate having a ten-mil (0.25mm) coating of the formulation in Table IV was heated at 158 F (70 C) for 20-30 minutes to drive off the solvent, followed by one hour at 266 F (130 C) to cure the prepolymer. Properties of this cured coating are listed in Table II. Higher temperature, for example 302 F (150 C), may shorten the time to cure the prepolymer. Pigmented coatings can readily be prepared with ADIPRENE BLM 500. Solventless mixtures of ADIPRENE BLM 500 and MDA can be prepared by melting the MDA at 212 F (100 C) and adding it with continuous agitation to ADIPRENE BLM 500 which has been warmed to about 158 F (70 C). a Viscosity vs. temperature of ADIPRENE BLM 500 is given in Table V. Storage life will be reduced if ADIPRENE BLM 500 is heated above 176 F (80 C). It may be necessary to heat solventless blends during application to achieve a workable viscosity. A blend of ADIPRENE BLM 500 and 10 phr MDA will remain fluid at 158 F (70 C) for more than one hour. ADIPRENE BLM 500 should also be considered in adhesive applications. The ability to be applied without solvents is a desirable feature in such applications. The cured film has a high degree of resistance to dry cleaning solvents and provides a flexible bond to fabric-to-fabric and flock bonding applications. Temperature, F ( C) TABLE V Viscosity of Adiprene BLM 500 Viscosity 122 (50) 13600 cps 140 (60) 6700 cps 158 (70) 510 cps a If the ADIPRENE BLM 500 or the agitator is not warm, molten MDA will crystallize before going into solution. The resulting crystals will dissolve at an extremely slow rate. 5 REV: 12/04dd:7/05dd