Calculation of catalysts in polyurethane soft foam formulations

The kinetics of the reaction between hydroxyl compounds and isocyanates
-D (- NCO)/dt=K0 x (- NCO) x (- OH)
K1 is the forward reaction rate of the formation of complexes between isocyanates and hydroxyl compounds
K2 is the negative reaction rate of the formation of complexes between isocyanates and hydroxyl compounds
K3 is the forward reaction rate at which complexes react with hydroxyl compounds to form aminoformates and hydroxyl compounds.
K0=[K1 x K3 x (- OH)]/[K2+K3 x
Arrhenius equation
K=Ae ^ [- (Ea/RT)]
A: Exponential factor.
E=2.718
Ea: KJ/mol
R=8.31 (J/mol. K)
Calculation of reaction heat for the formation of functional groups such as urea, polyurethane, biuret, and urea formate:
Bond dissociation energy (KJ/mol)
C-N 205.1~251.2
C-C 230.2~293.0
C-O 293.0-314.0
N-H 351.6~406.0
C-H 364.9~393.5
O-H 422.8~460.5
C=C 418.6~523.3
C=O 594.1~694.9
Reactive equation
RNCO+rOH ? RNHCOOr
RNCO+HOH ? RNHCOOH+RNCO ? RNHCONHR+OCO ?
RNHCOOr+RNCO ? RNCONHRCOOr
RNHCONHr+RNCO ? RNCONHRCONHr
The volume ratio of gas to the total volume of the polymerization system (Vg/Vo) in the polymerization system affects the temperature control ability: gas monomers affect the concentration (mol/L), which affects the polymerization heat [Q (KJ/L)=Rp (mol/L) * (- H)]. The heat of polymerization is transferred to the gas dispersion medium, causing the gas to absorb heat and expand (PV=NR/T). After a sudden increase in temperature in the polymerization system, the gas releases and carries away a large amount of heat (approximately in a straight line with Vg/Vo)
When preparing polyurethane in one step, the activation energy of amino acids is about 60 (mol. K), and the activation energy of urea reaction is 17 (mol. K)
The foam system is easier to implement than the solution suspension system. Dispersive polymerization exhibits the Norrish Tromasof effect at the beginning of the reaction, slowing down the rate of change of chain growth parameters over time and improving the monodispersity of the product.
Dispersion polymerization is a method of separating the polymerization system into numerous fine foam by gas, so that the polymerization components can be converted into the surface liquid film of foam and the “polyhedral boundary liquid cell” connecting multiple liquid films can form a special dispersion phase for polymerization.
The foam system uses gas as the dispersion medium, and the gas expands and cools suddenly when it is heated, and the negative pressure generated when the gas escapes will further polymerize the residual single concentration of the system, and accelerate and carry the evaporation of water molecules and the removal of small molecules.
The dispersion effect of gas on the polymerization system is not equivalent to true dilution of monomers.
General formula for half-life of non first-order reactions
T=[2 ^ (n-1) -1]/[a x k x (n-1) x A ^ (n-1)]
Second order reaction rate constant
A+B ? Q+S
Kt=[1/(CA0-CB0)] x ln [(CB0 x CA)/(CA0 x CB)]
CA0 x Kt=[1/(1-M)] x ln {[M (1-xA)]/(M-xA)}, where M=CB0/CA0
Attachment:
Example of calculating the density of polyurethane soft foam
Universal polyether ternary alcohol Ppg: 50 pop: 50 tdi-80:42.8 hoh: 3.17 L-580:1 a33:0.34 sn: 0.17
Calculated: 4.34 2.17 6.51 38.2 112% 17% 5.2 1.74 122 Recalculated, 28kg/cubic meter
Example of Calculation for Polyurethane Soft Foam Catalysts
Universal polyether ternary alcohol ppg: 90 pop: 10 tdi-80:: 35.5 hoh: 2.2 L-580:0.84 Black slurry: 6
Calculated: A33:0.18 T-9:0.25
A33:0.14 T-9:0.24
A33:0.13 T-9:0.35
A33:0.12 T-9:0.30
Tolerance and turning points
Calculation of vertical foam flow rate and lifting speed:
Formula (for example only) PPG: 100, TDI: 80, HOH: 6, SI: 1.5, A33: * * *, SN: * * *, MC: 14.8
The diameter of the vertical bubble circular mold is 1.25.
Polyether flow rate is 12 kilograms per minute.
What is the speed of improvement in meters per minute
Calculate the formula density of 12 kilograms per cubic meter. The total weight of the formula is 173.5 kilograms. The formula volume is 14.46 cubic meters. Circular mold cross-sectional area: 1.23 square meters.
Set a loss rate of 5%.
Boosting speed: [14.46 x 12% x (1-5%)]/1.23=1.34 meters per minute.
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Where isocyanates can be used

Where isocyanates can be used

Isocyanate is an important organic chemical substance with a wide range of applications in several fields. The following are its main areas of application:

Production of polyurethane: Isocyanate is the main raw material for the production of polyurethane. Through the addition reaction with polyol or polyamine, the hardness, viscosity, density, toughness and other properties of polyurethane can be controlled, so as to prepare polyurethane with different applications. Polyurethane has a wide range of applications in foam, elastomers, coatings, adhesives, cellulose reinforcing materials and other fields.


Coatings manufacturing: Isocyanate can be used as a reactive solvent in coatings, reacting with hydroalcohols to generate coating resins, increasing the durability and toughness of coatings and making them more suitable for coatings under various conditions. At the same time, it can also make the adhesion of paint pigments stronger and improve the durability and stain resistance of the paint. This kind of coating is widely used in automotive paints, wood coatings, metal coatings and other fields.
Preparation of adhesives: Isocyanates can be used to produce various types of adhesives, such as water-based polyurethane adhesives, solvent-free adhesives, hot-melt adhesives and so on. These adhesives are widely used in the fields of furniture, shoe materials, automobile interiors, bookbinding and so on.
Biomedical materials: due to the reactivity of isocyanate, it can also be used in the preparation of biodegradable materials and artificial blood vessels, among others. Isocyanates also play an important role in the manufacture of medical equipment and artificial organs.
Other fields: in the printing industry, isocyanate can be used as a component of ink to improve the viscosity, fluidity and adhesion of ink; in the rubber industry, isocyanate can be used as an adhesive; in aquaculture, isocyanate can be used as a water treatment agent to play the role of bactericide and deodorant.
In summary, isocyanates have a wide range of applications in many fields such as polyurethane, coatings, adhesives, printing inks, biomedical materials and so on. However, although isocyanates are widely used, it is still necessary to pay attention to their possible environmental and health impacts in the process of using them, and ensure that they are used in accordance with the relevant safety regulations.

 

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Cyclohexanone – an important intermediate in organic synthesis

Cyclohexanone is a saturated ketone with carbonyl carbon atoms contained within a six membered ring. Although it is cyclic, its properties are similar to those of open chain ketones. It can undergo various reactions such as oxidation, polymerization, and substitution in the presence of a catalyst, and is an important intermediate in organic synthesis.
In the early days, domestic cyclohexanone was only an intermediate product of caprolactam, and the production capacity of manufacturers of cyclohexanone matched that of caprolactam units, with only a small amount of commercial cyclohexanone supplied to the market. The growth and development of cyclohexanone as an independent industry are mainly due to two reasons: firstly, the solvent use of cyclohexanone continues to expand, especially as a high-end organic solvent, it is widely used in industries such as coatings, inks, adhesives, etc., forming a large commodity market; Secondly, with the improvement of domestic production level, cyclohexanone plays an important role in the field of chemical synthesis. In addition to being used for synthesizing caprolactam and adipic acid in the field of chemical fibers, it can also be used to prepare various chemical products such as resins, polycaprolactones, and pharmaceutical intermediates.
Application in the field of chemical synthesis:
1. Caprolactam and Adipic Acid
The main purpose of cyclohexanone is to produce caprolactam and adipic acid, which are important monomers in the production of nylon, nylon 66, and other synthetic resins. In the downstream distribution of cyclohexanone, the chemical fiber industry accounts for over 90% of the total production.
2. Synthetic organic resin
Cyclohexanone can be used to produce cyclohexanone formaldehyde resin, porphyrin resin, aromatic polyamine solid resin, etc. Compared with similar resins, cyclohexanone formaldehyde resin (i.e. ketone formaldehyde resin) has the advantages of high hardness, good weather resistance and oxygen resistance, low viscosity, high glossiness, and compatibility with various paint materials. It is mainly used as a coating resin and is widely used in oil-based resins, alkyd resins, amino resins, acrylic resins, epoxy resins, etc. It can also be used as a dispersant and brightener for inks and ballpoint pen oils. Porphyrin resin has special anti-corrosion properties, which can resist acid corrosion and organic dissolution well, and can be used as an anti-corrosion coating. Aromatic polyamine solid resin can be used as an additive and chain extender for polyurethane rubber.
3. Dehydrogenation to ortho phenylphenol
As an important organic fine chemical product, o-phenylphenol has a wide range of applications and broad prospects. It can be used to synthesize new phosphorus containing flame retardant materials, anti-corrosion and bactericidal agents, printing and dyeing auxiliaries, etc. With further research on o-phenylphenol, its application fields will be wider. The cyclohexanone condensation dehydrogenation method is an ideal production process for preparing o-phenylphenol, with high product purity and wide application range, and has become the mainstream production process.
4. Polycaprolactone
Synthesis of cyclohexanone ?- Caprolactone, ?- Caprolactone is further cyclically polymerized to produce poly (caprolactone) under the action of a catalyst. Polycaprolactone is a white opaque solid with certain rigidity. In addition, it has good biodegradability, drug permeability, and the ability to stably release drugs for a long time. Therefore, polycaprolactone is widely used in drug carriers, coating toughening, biodegradable plastics, polyurethane modification, and other fields.
5. Pharmaceutical intermediates
Cyclohexyl diacetate, abbreviated as CDA, is an important pharmaceutical intermediate prepared from raw materials such as cyclohexanone, acetic acid, and acetic anhydride. It can be used as an intermediate in the production of antiepileptic drugs such as gabapentin.
6. Polyurethane additives
Cyclohexanone can be used to produce polyurethane additive PC8, downstream of which are polyether foaming catalysts, polyurethane foaming catalysts, etc. The terminal includes refrigerator hard foam, board, combination polyether, external wall insulation, insulation layer, etc.
Cyclohexanone is an important organic chemical intermediate with a wide range of applications, involving various fields such as clothing, construction, automotive, pharmaceuticals, packaging, and is closely related to our daily lives. As a major domestic supplier of cyclohexanone, Hualu Hengsheng provides first-class services and stable quality. It has established cooperation with downstream industries and will continue to maintain a stable and high-quality supply of cyclohexanone in the future.
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