| 摘要 |
Acid-curable, condensation-type resins, particularly phenolic resin prepolymers and urea-formaldehyde and/or furfuryl alcohol-formaldehyde modified phenolic resin prepolymers, have improved properties when admixed with a dibasic acid di-ester of the composition R1O2C(CH2)nCO2R2 where n is from 1 to 8, R1 is furfuryl, and R2 is furfuryl or methyl. The di-esters are preferably added in the amount of 5-35%, by weight of total composition. These compositions are particularly useful in the preparation of sand cores and molds for foundry use which have improved strength and hardness. The dibasic acid di-esters of the composition R1O2C(CH2)nCO2R2 where n is from 1 to 8, R1 is furfuryl, and R2 is furfuryl or methyl are not reported in the literature and are novel compounds. These di-esters are oily liquids having high boiling points and are particularly useful as resin modifiers, diluents and plasticizers. These di-esters are produced by the sodium-catalyzed transesterification reaction of furfuryl alcohol with the liquid dimethyl esters of the C3-C10 linear aliphatic dibasic acids at temperatures of about 214 DEG -240 DEG F.
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