Gives gathers the body law is produces time CPU to expand the chain reaction (to give gathers response) and expands the chain to hand over the association response to divide two step carries on, also the active weak response (polyols and isocyanogen diethylene glycol dinitrate give gathers response) to have the enough time to carry on, responded thorougher, obtains gives gathers the body with to expand the chain medicinal preparation to respond again, obtains elastomer structure evener, is advantageous forms the hydrogen bond during hard section to the polyurethane macro-molecule, also favor hard Duan Heruan in the section between the strong µç¸ºÐÔ groups and bases to produce the hydrogen bond, enable the product to have the good mechanics performance, the duplication is also better, Therefore present mostly CPU uses gives gathers the body law preparation. This article introduced gives gathers the related craft and the equipment aspect elementary knowledge which the body produces, refers for the related technical personnel.

First, raw material:

1st, the low-molecular polymer polyols (gathers mellowly)

(1)    polyester polyols (PES)

In    (1) polyester member includes more polar ester base (- COO -), may form a stronger intramolecular hydrogen bond, therefore the polyester polyurethane has a higher intensity, is wear-resisting and the oil resistant performance. The polyester price is moderate, is in the majority in CPU by the polyester, the commonly used polyester polyols is the molecular weight (Mn) 1000~3000, a double function linear polymer, under the usual normal temperature is the waxy solid.

Partial polyester trademark and nature (relative molecular weight Mn ¡Ö 2,000)

Note: AA: Adipic acid, EG (or EDO): Glycol, PG (or PDO): Trimethylene glycol, DEG: Two glycol,

TMP: Three methylol propane; TPP: Triphenyl phosphite; BHT: 2, 6- two uncles butyl - methyl phenol (namely antioxidant -264), 1, 4BG (or BDO, BD) 1, 4 butylene-glycol.

(2)    gathers in the oneself the mellow polyols (PCL), is the special polyester, the similar polyester oil resistance, the good mechanics performance, bears the low temperature performance and the thermostable performance, similar polyether fine water resistance, but the price is higher.

(2)    the polyether polyols (PET), the elastomer commonly used poly four hydrogens ß» à« two to be mellow (PTMG) and gathers the oxidized propen.diol (PPG)

(1)    PTMG CPU higher module and the intensity, outstanding bear the hydrolisis, is wear-resisting, bears the mold, oil resistant, the electric insulation performance and the low temperature flexibility. Especially uses in the automobile fitting, the medical supplies, the high performance rubber roller, the oil resistant seal and uses in submarine underground, the mine pit and the low temperature situation product.

(2)    PPG includes more ÃѼü and the side methyl, therefore the system results in the CPU product has a better flexibility and »Øµ¯ÐÔ, but because the side methyl influence elastomer soft section has the foreword to crystallize, also ordinary PPG contains the few single hydroxyl polyether impurity, causes the CPU intensity not too to be high, therefore only uses in the not too important product.

2nd, two isocyanogens diethylene glycol dinitrate, commonly used TDI, produces high grade CPU to be in the majority with T-100, because pure 2, 4TDI (T-100) NCO is located the toluene groups and bases 21 and on 41, responded the active difference several fold, causes it gives when the preparation gathers the body to respond evenly, the production molecular weight distribution narrower, the viscosity is lower, the performance well gives gathers the body. But the T-100 price approximately is high higher than T-80 50%, therefore T-80 also massively uses in the CPU production.

Second, production craft:

1st, gathers the mellow dehydration: Because gathers mellowly possibly contains the few moisture contents, if not responded except the volunteer fire brigade and TDI, not only consumes massive expensive TDI (the 1g water to consume 9.67gTDI), but also can emit the carbon dioxide (the 1g water to produce 1200mLCO₂), the sparging affects the product quality in CPU. Thus gives in the synthesis gathers in front of the body, must to gather mellowly carries on dehydrated processing. Will gather mellowly in the dehydrated cauldron, will stir (60r.p.m) in the low speed and about vacuum degree5~10mgH₂ O, (1mgHg=133pa) will heat up to 120~140 ¡æ (polyether heats up to 100~120 ¡æ), the continual reduced pressure will process the 1~3 hour. The dehydrated time is decided to gathers the mellow quantity, the water content and the dehydrated cauldron structure. Regarding large-scale, industrial production, may use the film evaporator or the spray-drying process dehydration.

2nd, gives gathers the body synthesis:

(1)    formula design: According to the product performance requirement, the use environment and the request life and so on the choice appropriate raw material, presses the design degree of hardness to designate again the appropriate allocated proportion and takes shape the method.

Usually uses gathers mellow TDI is two functional compounds, is different (R=NCO/OH) according to the R value to be able to form three kind of different structures the intermediates:

When R > 2, gives gathers the body is by two isocyanogens diethylene glycol dinitrate sealed end low-molecular polymer polyols and two isocyanogens diethylene glycol dinitrate mixture.

When R = 2, gives gathers the thing is by two isocyanogens diethylene glycol dinitrate sealed end low-molecular polymer polyols product. (Theoretically exactly should be 2 two isocyanogens diethylene glycol dinitrate and 1 polyols responded that, the production end - NCO base gives gathers body).

When 1 < R < 2, gives gathers the thing is the low-molecular polymer polyols and expands the chain by two isocyanogens diethylene glycol dinitrate the product. (Molecular weight bigger, molecular weight score is bigger).

Take R=1.8~2 as good, gives gathers the body viscosity moderately, ÍÑÅÝis easy, the product overall performance is good. R more approaches 1, gives gathers the body viscosity to be bigger. When R will surpass after 2, gives gathers the body viscosity obviously to reduce, is easy the small molecular isocyanogen diethylene glycol dinitrate which has Ö§»¯ the response or appears drifts away, the storing stability drops, will appear the massive isocyanogens diethylene glycol dinitrate gas volatility in the operation to impair the operator health and to pollute the workshop air.

(2)    formula computation:

NCO/OH or - the NCO base content is the attribute gives gathers the body quality important target. Gives gathers in the body - the NCO content to enhance, then gives gathers the body viscosity to reduce, is easy ÍÑÅÝand the mix is even, in the cauldron loss of life, also degree of hardness, the intensity, the module enhance. Often is 3~10%.

   

3rd, the formula gives an example (only to supply reference)

(1)    polyester - TDI - MOCA   [ polyester: Gathers the adipic acid glycol ester two to be mellow (PEA) ]

(2)    polyester - TDI - MOCA (polyester: Gathers the adipic acid glycol, the trimethylene glycol, glycol/trimethylene glycol =80/20, Mn=2000)

Third, technological process and equipment

1st, the present small scale multi- varieties produce CPU to give gather the body mainly to have two kind of technological processes and the equipment

(1) uses the double response cauldron installment: A dehydration, a synthesis gives gathers the body and ÍÑÅÝ:

The polyester (or polyether) (melting) joins in the dehydrated cauldron after the measurement to heat up (polyester 100~140 with the pump circulation heat conduction oil ¡æ, polyether 100~110 ¡æ) dehydrates the 1~2 hour under the 5mmHg vacuum degree (idling speed to stir), when is lower than 0.05% to the water content, with the pump circulation cold heat conduction ÓÍÀäÈ´ to 40~60 ¡æ, relieves the vacuum, joins it after synthesizes the cauldron in TDI (Òµ¾­ °õ³Æ measurement with to pump joins synthesizes in cauldron) to elevate temperature 30~40min after exothermic but the nature, slowly heats up to 80 ¡æ ¡À5 ¡æ, the heat preservation stirs responds 2~3h, the sample analyzes the NCO content, when basically tallies with the design value, After ÍÑÅÝnamely gives gathers the body.

 

In (2) uses the gallbladder activity type response cauldron, will dehydrate, the synthesis and the degasification completes in an equipment. Moistens has the material in the stainless steel the gallbladder to be possible freely to take out, is advantageous for the cleaning up, avoided responding the cauldron the clear cauldron difficult problem, to gave gathers the body variety to change more CPU production factory to be more practical. Its flow and on the chart is similar, will dehydrate the cauldron and the synthesis cauldron merge will only be then.

2nd, main equipment

(1) responds the cauldron: Makes the polyols dehydration, gives gathers the body synthesis and the degasificate using of.

(1)    general structure response cauldron: Uses in the stainless steel the gallbladder, attaches hot or cools the clamp cover and outside a package of polyurethane hardly soaks ¾øÈȲã three structures responses cauldron, attaches the anchor type to stir (attaches precision revolution axis seal) in the cauldron to be equipped with feeding, the material, the observation, measured warm, measured the pressure and the vacuum, safely blow off and craft and so on vacuum ¹Ü¿×. Its volume decides according to the request output, commonly used volume and size: 80L (phi 400¡Á500); 120L (phi 500¡Á500); 200L (phi 600¡Á700) and so on.

(2)    in gallbladder Yi Xieshi responds the cauldron: Four structures responses cauldron stirs which for the belt, the structure and the request and above basic are same, only in the stainless steel the gallbladder, may use the aerial cable car which sets up as an attachment very conveniently to hang in the gallbladder, in order to help clean.

(2) controls warm and the heat conduction ÓÍÑ­»· system: Causes the polyols or gives gathers the body to achieve the request temperature, satisfies dehydrated and the response need.

(1)    heating system: In the hot fuel tank the electric heating tube causes the heat conduction oil to heat up to the request temperature, transports from the circulating oil pump the hot oil to in the response cauldron clamp cover spiral channel, heats up in the cauldron the original fluid (or response fluid), after but the heat conductivity hot oil fills the clamp cover the overflow to return to the hot fuel tank, because the heat conductivity hot oil pump circulation heats up in the cauldron the raw material (or response fluid).

(2)    cooling system: In cold fuel tank cooling water plate tube (when necessity coca refrigerator) causes the heat conduction ÓÍÀäÈ´ to the request temperature, when in the response cauldron clamp cover the hot oil completely puts to the hot fuel tank in after, transports from the circulating oil pump the cold oil to in the response cauldron clamp cover spiral channel, cools in the cauldron the original fluid (or response fluid), after but the cold heat conduction oil fills the clamp cover the overflow to return to the cold fuel tank, because the cold heat conduction oil pump circulation cools in the cauldron the raw material (or response fluid). When in the clamp cover must pass over once more the heat conductivity hot oil heats up, must first the clamp cover in cold heat conduction oil return in the cold fuel tank.

(3)    controls the warm system: Reveals warm by the intelligence time proportion type number controls the meter to control the original fluid, hot oil and cold oil temperature: Heats up (electricity heat pipe and hot oil pump) cools (cold oil pump and cooling water switch and refrigerator), may enable it to achieve the request temperature (error < ¡À2 ¡æ)

(3) vacuum system: Responded the cauldron (commonly used multilayer keeps off beat) after the vacuum cushion pot (commonly used to turn on lathe piece type) to the vacuum pump, responded in the cauldron the vacuum pressure gauge may demonstrate its vacuum degree or the sufficient nitrogen pressure. Requests the pipeline as far as possible short, also the attachment and the valve are few, guards against leaks air. In order to evade shakes, middle may use the hose to join.