Abstract: The physical and chemical properties of dimethyl carbonate and dimethyl carbonate cited (DMC) in the polyurethane shoe adhesive, toluene-free graft neoprene adhesive for shoes in the application can be obtained partial substitution of DMC expensive methyl ethyl ketone, acetone, ethyl acetate, propyl butyricum conclusion.
Keywords: dimethyl carbonate; shoe adhesive; polyurethane; chloroprene rubber as
Dimethyl carbonate (DimethylCarbonate) referred to as DMC, is a new chemical raw material, over the past decade, DMC and its derivatives research and development, has become one of the hot chemical research and development breakthroughs, applications also increasingly to expand. As DMC's unique molecular structure (CH30-CO-OCH3), it not only as a place of dimethyl sulfate methylation reagent instead of phosgene as a dial-based agent, may also increase gasoline octane and oxygen content as the gasoline additive. In addition, DMC also has a fast evaporation rate, solvent compatibility with other good characteristics. Thus, over the past decade the development and application of DMC attracted wide attention at home and abroad the chemical industry.
The main products are shoe adhesive neoprene adhesives, polyurethane adhesives, which are solvent-based adhesive, its components, 75% of which is solvent, its use of organic solvents are toluene, benzene, xylene, acetone, methyl ethyl ketone , ethyl acetate and so on. Most of the organic solvent because of serious health and environmental hazards, therefore, at home and abroad are actively developing low-pollution, low toxicity of the shoe adhesive. DMC as a good low-toxicity solvent, in the production of shoe adhesive showed good development prospects.
DMC physical and chemical properties
DMC at room temperature is a colorless, transparent, slight smell, slightly sweet liquid, melting point of 49C, boiling 90.1cc, density 1.0698/em3, insoluble in water, but with alcohols, ethers, ketones, etc. Almost all of the organic solvent
Agent miscible oDMC low toxicity on mice, rats lethal dose LDP = 6400-12800mg/kg, Europe in 1992 was classified as non-toxic product, is a line of modern, "clean technology" environmental protection requirements organic solvents . Table 1 is commonly used DMC and shoe adhesive solvent part of the physical and chemical nature of the comparison.
DMC in shoe adhesive Production Research
Solvent is the main component of shoe adhesive, solvent adhesive nature of the performance for a great impact. Adhesive viscosity, drying rate, hold time viscosity, tack, construction, toxicity, safety, cost, cleanliness, storage stability, and so closely related with the solvent, nature of the solvent made a lot of requirements, such as stronger solvent power , moderate evaporation rate, the appropriate temperature not gel, odor and toxicity to the small, relatively safe to use price as low as possible, even easy to source and so on. There is no doubt that a single solvent is difficult to meet these requirements, and a mixed solvent system is a good overall performance .According to DMC's solubility parameter, evaporation rate, price, and other indicators of toxicity characteristics of adhesives in the shoe does not advocate a single use, mainly tend to compound with the other solvents used, so as to minimize toxicity and adhesives for shoe production The role of cost.
DMC in solution-based polyurethane shoe adhesive application
Polyurethane structure exists because of the polarity of imino, call the base, ether bond and a reactive isocyanate, and a variety of materials with good adhesion.
Which are often widely used as a polyurethane reactive adhesives. Choose the variety of variable structure, can be obtained with room temperature curing, good low temperature resistance, impact resistance, oil resistance, abrasion resistance, Rao and high peel strength curve of the comprehensive performance of adhesives, polyurethane adhesives in the shoe production become an important class of varieties.
At present, there are a large part of the production of polyurethane adhesives for shoe factories are directly imported polyurethane resin dissolved in methyl ethyl ketone, acetone, the preparation of polyurethane shoe adhesive. In the experiment, we replaced part of the DMC ethyl ketone (MEK), the results shown in Table 2.
As can be seen from Table 2, DMC can replace the PU glue in some of MEK, adhesive bond strength has not changed, but the viscosity, initial adhesive strength has a tendency to become smaller. Therefore, the actual production should be based on the requirements of shoe line, the appropriate amount of the adjustment DMC, the DMC recommended dosage is 30% of the total volume of solvent.
DMC without toluene in the SIN-based polyurethane adhesive for shoe Jing application
SIN-based polyurethane adhesive for shoes without toluene  is that we adapt to the environmental requirements developed new varieties of polyurethane shoe adhesive. It is based on the import of solid polyurethane resin modified, the solvent is methyl ethyl ketone as a mixture of acetone, ethyl acetate, in order to reduce costs, we use the DMC is one of the components of mixed solvents, synthesis of SIN toluene-free polyurethane adhesive for shoes, and the results shown in Table 3.
Table 3 shows, DMC can replace part of the acetone, methyl ethyl ketone, ethyl acetate, polyurethane adhesive for the SIN-based synthesis, and its performance fully able to meet the requirements of DB35/329-1999, and DMC in the SIN-based polyurethane coolthe application of glue is better than ethyl acetate phenol good.
DMC graft neoprene in the application of
Graft-free toluene neoprene shoe adhesive prisoners is a good job with the Fujian Provincial Environmental Protection Bureau, Fujian Province, the footwear industry, "toluene" waste management program implementation, preparation of a composite initiator of A-90/MMA/AA three yuan graft without toluene plastic beach slippers. The solvent system of methyl ethyl ketone and n-propyl acetate, due to methyl ethyl ketone, n-propyl acetate is expensive, so in order to replace part of the DMC-propyl acetate, methyl ethyl ketone or significantly reduce the cost of non-toluene rubber beach slippers, the results of its application shown in Table 4.
Seen from Table 4, DMC can replace part of methyl ethyl ketone, n-propyl acetate, toluene-free graft for the synthesis of neoprene, fully meet the performance standards of the original 141 but no toluene greatly reduced the cost of plastic beach slippers .
Dimethyl carbonate as a low toxicity solvent, laboratory studies have shown that can be used to cool shoe adhesive and polyurethane graft neoprene adhesive, partial substitution of expensive acetone, methyl ethyl ketone, ethyl acetate. n-propyl acetate.Of course, since each shoe adhesive formulations of different manufacturers, DMC should be given in the application of a comprehensive survey.
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