Furan resin sand curing agent selection

Furan sand is acid as a curing agent. Commonly used organic acid benzene sulfonic acid, toluene, xylene yellow yellow acid such as acid, inorganic acid, such as phosphoric acid sulfuric acid ethyl ester. When the phosphate as curing agent, the prepared core hygroscopicity, and phosphate in the sand in easy storage, only in the ductile iron or low carbon stainless steel case, in order to prevent the casting surface permeability S and with small amount of phosphoric acid, general regeneration sand using phosphoric acid as a curing agent;

Sulfuric acid corrosion resistance, preparation time also has the certain risk, although the curing speed, but the final strength is not high, but also in the sand accumulation problem, only in the disposable since the hard sand, but the temperature is too low when used. Generally uses organic acid by curing agent.

Toluene sulfonic acid is a white crystalline powder, soluble in water or alcohol use, according to their acidity and concentration of different, generally suitable for Yu Chun, summer, autumn, xylene yellow acid is more adaptive, according to the acid value and the concentration of the different, a year can be used in four seasons.

Curing agent technology parameters are mainly acid, free sulfuric acid content, viscosity.

ZHUHAI DOUMEN FULIAN MOLDING MATERIALS INDUSTRY CO., LTD
Add: Xinqing 6Rd, Xinqing Ind. Zone, Doumen District,

Zhuhai City, Guangdong Province , China (519180)

Tel:    86-756-5550295
Fax:   86-756-5212666
Mob: 86-15113139527
Skype: rubin.liu1
E-mail: rubin@gdfulian.com
Web: www.gdfulian.com/en

Effects of furan resin sand hardening speed factor

Furan resin hardening speed in the production process is particularly important for sand box size, filling sand and small sectional area of the mold, can improve the rate of hardening resin sand box; the size of filling sand and a large cross-sectional area cast, in order to guarantee the use time, prevent sand mud layer, then to control the rate of hardening. A plant resin sand hardening speed control quality, directly affects the production proceed smoothly. Usually affect the resin sand hardened factors include the following aspects.

1, furan resin in water is relatively high, will inhibit the polycondensation reaction, reduce the rate of hardening; resin pH value is too high, will consume more curing agent, also reduces the rate of hardening.

Curing agent2, total acidity and free acid content was measured in curing agent activity are important indicators, generally with the total acidity and free fatty acid content increased, the prepared resin self hardening hardening speed, conversely, is hardening speed slow down; in addition, the curing agent dosage must be strictly controlled, in 20% to50%, adding more faster, hardening.

3, the temperature and humidity of environment is the impact of hardening speed of important factors, the higher the temperature, curing agent on grease catalysis and more intense, hardening faster; environment with high humidity can affect the moisture evaporation rate, the hardening rate slows down, especially in a long time in the environment humidity is too high or too low, hardening speed very obvious.

In 4, the sand temperature than the air temperature can affect the rate of hardening resin sand, as long as there are sand temperature, solid velocity is accelerated apparently; if the sand temperature greater than 40 DEG C, then mixing the resin sand can use time can not satisfy the need of production.

In 5, the new sand moisture in high and new sand and used sand in the acid consumption value, one can reduce the curing agent for the resin catalysis, on the other hand will consume part of curing agent, from infants to lead hardening speed slows down.

In 6, mixed resin sand equipment after years of use, the components of friction is large, big mixing process will produce heat, and the hardening speed.

7, using the correct sequence of feeding and appropriate mixing time contribute to obtain high quality resin sand, general sand mixing process: sand + curing agent, mixing - about 1 minutes, and resin, mixing - around 0.5 points out of the sand.

The order can not be reversed, or bureau will radically curing reaction, shorten the time of resin can be used; after adding the mixing time can not be too short ( too short mixing unevenly ) and long ( long sand temperature rise, can use a shorter time ).

ZHUHAI DOUMEN FULIAN MOLDING MATERIALS INDUSTRY CO., LTD
Add: Xinqing 6Rd, Xinqing Ind. Zone, Doumen District,

Zhuhai City, Guangdong Province , China (519180)

Tel:    86-756-5550295
Fax:   86-756-5212666
Mob: 86-15113139527
Skype: rubin.liu1
E-mail: rubin@gdfulian.com
Web: www.gdfulian.com/en

Furan resin types and performance

Furan resin as a brownish red, amber viscous liquid, slightly soluble in water, easily soluble in ester, ketone in organic solvent, casting industry ideal sand, core binder. The characteristics of core sand, good accuracy, high strength, low odor, moisture resistant, good sand collapsibility and recyclable use etc..

Furfural furfuryl alcohol itself or by homopolymer or with other monomers by polycondensation and get the condensation product, known as customary furan resin. This type of resin in many varieties, including furfural phenol resin, furfural acetone resin and furfuryl alcohol resin is more important.

(1) furfural phenol resin

Furfural phenol condensation polymerization with two order thermosetting resin condensation reaction with alkaline catalyst, general. Commonly used alkaline catalyst with sodium hydroxide, potassium carbonate or base it alkaline-earth metal hydroxides. Furfural phenol resin is mainly characterized in that the curing speed given longer time of flow, the process properties make it suitable for molding plastic. Using furfural phenol resin preparation of moulding powder is particularly suitable for compacting more complex shapes or larger products. Molded products heat resistance than phenolic resin, using temperature can be increased by 10 ~20 C, dimensional stability, good electrical properties.

(2) of furfural acetone resin

Furfural and acetone under alkaline conditions condensation reactions to form the furfural-acetone monomer fun with formaldehyde in acid conditions further condensation, the furfural-acetone monomer molecular Yici methyl bond linking, formation of furfural acetone resin.

(3) furfuryl alcohol resin

Furfuryl alcohol under acidic conditions are easy to condense into resin. Generally, in the condensation process of furfuryl alcohol molecules in the hydroxymethyl can with another molecule of a hydrogen atom condensation, formation of methylenekeys, condensation product formed is still hydroxymethyl, can continue for condensation reaction, eventually forming linear polycondensation product of furfuryl alcohol resin.

Performance and application of furan resin -- not cured furan resin and thermoplastic and thermosetting resins have good compatibility performance, so it can be with epoxy or phenolic resin mixture to be modified. The cured furan resin resistant to acid ( strong oxidation of nitric acid and sulfuric acid with the exception), alkali and organic solvent erosion, still very stable at high temperatures. Furan resin mainly used for a variety of chemical corrosion resistance and high turbid materials.

(1) chemical corrosion resistant material

Furan resin can be used for preparing anticorrosion clay, used for lining chemical equipment or other corrosion resistant material.

(2) heat resistant materials

Furan glass fiber reinforced composite heat resistance than general phenolic glass fiber reinforced composite material high, usually at about 150 DEG C for long-term use.

(3) and an epoxy or phenolic resin modified

Furan resin and epoxy or phenolic resin can be improved using mixed recuperation, furan glass fiber reinforced compositesmechanical properties and the preparation process and properties of. The composite material has been widely used for thepreparation of chemical reactor with stirring device, storage tank and pipeline and chemical equipment.

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