Resinous of not saturated polyester manufactures technology
Lab synthesis
Not saturated polyester is synthesized in lab, it is new to studying resinous recipe and craft, trial-produce product, important to improve old product to have meaning. Lab synthesis equipment is simple, the operation is convenient, with makings province, be devoted batch unripe antenatal surely classics phase.
Lab synthesizes unit motion to be like graph 5-5. Basically be a 3 buccal flask, how to have beater, device can heat with electric heat or annular gas burner below. The thermometer is inserted to be able to observe reactant temperature at any time in an opening of flask, insert inert gase to provide fluid cover at the same time next undertaking bosomy bubble agitate. Circumfluence valve is installed in the another opening of flask, reclaim mellow and remove moisture, its coping inserts the 2nd thermometer in order to determine vapour temperature. Vent-pipe exit can install small vavuum pump of a bypass, enforce with vacuum in reaction later period dehydration. It is with general polyester exemple, can have operating sequence of the following synthesis. ① rinses the system clean with inert gase. The third that ② adds exact amount to the middle of flask 2 alcohol, benzene anhydride of 2 formic acid and suitable Ding Xi 2 acid anhydride. ③ begins to heat, calm time is 0 when; Inert gase discharge can be S of 2 bubble / ; Begin agitate, agitate undertakes terminus all the time after. Every half hours of record in ④ reaction process reactant temperature and vapour temperature. When reactant temperature rises 175 ℃ to control, begin circumfluence; Temperature falls to be controlled for 160 ℃ namely, continue circumfluence. After ⑤ circumfluence undertakes 15min, with move fluid is in charge of sampling, determine acid value. Later every half hours determine, make a record. Determine the appraise after the method. When ⑥ acid value falls to be controlled to 200mg / G, change condenser, make moisture OK distillation goes out. Raise reactant temperature to come 175 ℃ , vapour temperature must not exceed 105 ℃ , reactant temperature maintains 175 ℃ , make acid value falls for 135mg / G. ⑦ increases inert gase discharge to come 4 ~ S of 6 bubble / . Elevatory reactant temperature reachs 190 ℃ in the meantime, react continuously, amount to to acid value (50±2)mg / G. ⑧ joins pair of benzene 2 phenolic block get together agent, the 0.02 % that dosage is child gross (quality mark) . ⑨ makes colophony cooling, drop in temperature 90 ℃ . ⑩ joins styrene, make child cools as soon as possible. Acid value reflects the hydroxyl volume that the rest in colophony did not react, with titrate of solution of potash of 0.1mol / L, calculates so that every overcome colophony to need titration KOH quality (Mg) , it is acid value namely. Acid value size reflected the rate that synthesis has. Still need to determine in whole reaction process actually viscosity, make a record. Can reach then two curves in reaction process, namely acid value - time-speed-distance curve and viscosity - time-speed-distance curve. Its example sees graph 5-6 and graph 5-7.
Synthesize every time should make actual record to all reaction process. The record must be memoir data, record at that time, cannot cite posthumously of after the event. Acid value curve and viscosity curve are the significant evidence that controls manufacturing process. Basis for many times complex data can make standard curve, in order to contrasts it is normal to examine this second synthesis process. If deviate should take step in time greatly relatively,try to correct. The reaction that above place narrates did not use solvent in the process, it is the process of melt condensation polymerization of binary acid and binary alcohol. But polyester reaction also can exist in proper dissolvent next undertaking. Solvent is commonly used 10 % (quality mark) mixture xylene. In reaction process xylene and water are formed in all boil mixture, make water eliminates faster, quickened condensation polymerization to react greatly thereby, the dissolvent when reaction cease is natural also distillation eliminate. Its lab synthesizes device to see graph 5-8. There is a powerful person of soda water of form of a t-shaped in the circumfluence that flask comes out, make the condensation content of inhomogenous photograph departs automatically for two-phase, solvent returns flask, and take water in below paragraph, can undertake metric. The polyester viscosity that makes with place of this kind of craft is inferior, because reaction undertakes,the likelihood is fast. Temperature is low, cause all get together the reason with less thing.
The workshop manufactures technology
(1) casts material process ① to join all sorts of alcohol first, attenuant dissolvent is joined when need (the 10 % that join a quantity to be reactant total mass control) . ② heats liquid constituent to be controlled to 100 ℃ . ③ actuate mixer, xiang Chunzhong connects affection sex gas. ④ successive joins solid reaction to expect (the) such as acid anhydride. When joining solid reaction to expect, should join 0.02 % of 0.01 % ~ sometimes (quality mark) block gets together agent or stabilizing agent, become angry in order to avoid reaction stock or premature gel. When if need to join ester,changing reaction activator, also joining right now. ⑤ continues agitate warms up. Reaction is right now intense undertake, the rate that produces water is very rapid. Reaction expects to the cubage inside boiler is held to must not exceed 80 % after be being added, can create risk bosomy bubble otherwise. When reaction stock is liquid state entirely, can add cold stock first and warm up, stock heats after, add all sorts of liquid state stock entirely below agitate. When if return,having other solid stock, again by enter into Kong Jia, need to have into aperture remove dust goodly safeguard. (2) warms up speed warms up speed depends on the depart of the boiling point of binary alcohol in reaction makings and fractional column to alcohol and reclaiming efficiency. General and usable rapidder rate warms up, produce cycle in order to shorten. But want to notice, reaction of reaction initial stage undertakes very fast, produce a large number of water, in had warmed up fast when, of water evaporate can take away a large number of alcohol, mellow boiling point is lower, take away more, the ability when fractional column efficiency is very only tall comes out mellow all depart, undertake circumfluence. (Temperature of reaction of 3) reaction temperature rises 190 ~ after 200 ℃ , maintain this temperature namely, until till reaction is complete. The control of fast response temperature inspects different colophony what to use raw material recipe and be decided. Temperature is high, although can make reaction is quickened, but make colophony becomes angry likely reach produce premature gel. If raw material is right in reaction process heat is sensitive (be like) of anti-flammability former division, or when the product asks definition is high, be about to control inferior reaction temperature appropriately. (4) reacts time is below fast response temperature, the accident of reaction time depends on the following element. All sorts of acid and alcohol have the property of ① reactant its specific response is active, decided the discretion of response rate. The pitch that ② reacts the requirement is achieved should not occur gel only commonly, can make reaction is achieved as far as possible complete. The level that reaction may reach is concerned with density of not saturated Shuang Jian in polyester again. When not saturated key is little, the possibility that forms cross-linking and premature gel is little, reaction can have higher rate surely. Total response rate asks related to manufacturing cost, higher response rate asks longer production is periodic, raised manufacturing cost. Synthesize for example get together suitable Ding Xi 2 acid, glycol ester, acid value can amount to left and right sides of 40mg / G, always heat time makes an appointment with 6h; Synthesize oneself is 2 acid, suitable Ding Xi 2 acid, third 2 mellow polyester (oneself 2 acerbity 6mol, suitable Ding Xi 1mol) of 2 acid anhydride, acid value can achieve 5mg / G, reaction time needs 16h. Want to consider many sided element integratedly to decide reaction time consequently. The loss circumstance of ③ alcohol and the loss that excessive excludes efficiency acerbitily to be like alcohol are apparent, react time should shorten appropriately. Sometimes polyester system already achieved viscosity requirement, but acid value is very high still, the inert gase that can use large flow strengthens agitate, make free acerbity monomer is divided from send a manuscript to the compositor of the brandish in reaction mixture, reduce acid value, extended reaction time accordingly namely right now. (The complement of 5) alcohol should volatilize mellowly the loss is bigger, when making acid value backwater is hard to drop, the acid value that determines in reaction process for a short while the curve is apparent deviate standard curve, need seasonable complement to join binary alcohol. Complement joins a quantity to be able to press type calculates:
If represent compensatory and binary mellow quality with △ G; Q represents total mass of the stock inside boiler; △ AN represents number of acid value deviate; Mg represents amount of binary mellow element, go up type can simplify for:
(6) ester changes the activator of reaction to want to quicken ester to convert reaction, effective method is the activator that joins alcoholization reaction in the begining in reaction. Practicable activator has pair of toluene inferior acerbity or sulphur is vitriolic, other if gas is chloridize hydrogen, anhydrous chloridize zinc, tannin, anxious