The hottest polyurethane reactive extrusion equipm

Polyurethane reactive extrusion equipment

1. Raw materials:

(1) polymer glycol: polyester polyol (PES)

pea (polyethylene adipate) m=2000, hydroxyl value 55 ± 3 mgkoh/g

pda (polyethylene adipate glycol ester) m=2000, hydroxyl value 56 ± 2.5 mgkoh/g

pba (polyethylene adipate glycol ester) m=2000, Hydroxyl value 56 ± 2.5 mgkoh/g

(2) diphenylmethane diisocyanate (MDI) (aromatic)

pure MDI is a white or yellowish solid at room temperature, with irritating odor when heated, melting point ≥ 38 ℃, boiling point 194~199 ℃/5mmhg, density: 1.19

molecular formula and molecular weight: c15h10n2o2; 250

(3) chain extender (low molecular glycol):

1,4 butanediol (BDO) (fat chain opening glycol)

is a colorless oily liquid, which is very easy to absorb water, with relative molecular weight m=90.1, density 1.02, boiling point: 229.5 ℃, melting point 20.1 ℃

2 Formula:

pes (mw2000, difunctional degree) 1 mole

mdi 3 mole

bdo 2 mole

isocyanate index r= (nco/oh) =0.97~1.03

performance: density 1.2 hardness (Shao a)

tensile strength MP 300% modulus MPa

elongation% tear strength MPa

abrasion (gram loss) 0.0025~0.15 embrittlement temperature -17~-30 ℃

3 Production process:

melt the polymer polyester glycol (PES) and add it to the a material tank. Heat it to the required material temperature (100~120 ℃), and then vacuum dehydrate it for 2~3h under low-speed stirring, so that its water content is less than 0.05%. Remove the vacuum and pass nitrogen for standby

melt the MDI and add it into the B material tank. Heat it to the required temperature (60~70 ℃), and then vacuum degasify it for 0.5~1h under low-speed mixing. After it meets the requirements, remove the vacuum and supply nitrogen for standby

add low molecular diol (BDO) into the C material tank, heat it to the required temperature (30~50 ℃), and then vacuum dehydrate it for 0.5~1h under low-speed mixing, so that the water content meets the requirements, remove the vacuum and supply nitrogen for standby

in order to continuously feed each metering pump of the pouring machine, each component is equipped with two sets of charging tanks of the same specification, so as to achieve vacuum dehydration and feed the other metering pump

according to the formula requirements, the raw liquid of each group is accurately measured by the metering pump and transmitted to the pouring head. After uniform initial mixing under high-speed mixing, it is transmitted to the double screw reaction extruder to further mix evenly and react chemically, and then it is granulated and screened

4. Technological process (using twin-screw continuous process)

(1) raw material treatment: melt the raw materials, reach the required temperature and degasify. In order to achieve continuous production, two groups of storage tanks are equipped for degassing. The spline is placed on the two supports of the fixed machine tool of the experimental machine and fed

(2) TPU pouring machine: continuously and accurately measure and initially mix each component

(3) twin screw reaction extruder: further mixing, chemical reaction and transportation of materials. (the two shafts rotate in the same direction, fully engage, and have self-cleaning effect)

has the following characteristics:

① react under high temperature and high PEF with greater polarity pressure than other materials (temperature 140~250 ℃, pressure 4~7mpa) to ensure that the side reactions are minimized, and high pressure can inhibit the decomposition reaction with gas

② reduce the mass fraction of low molecular weight oligomer (~1500g/mol) to the lowest (~0.36%)

③ there should be a high shear velocity gradient (> 2000s-1) between the two relatively moving screws to make the materials well mixed, homogeneous and complete, so that the reaction is uniform, and there will be no local gel. Kneading times can reach 7~15 times/s

④ it is required that the temperature control of each section of the barrel must be uniform and accurate, with rapid heating and cooling functions, and should have good heat transfer efficiency. Examples of temperature control parameters in each section:

temperature control in the first section is 80~180 ℃, temperature control in the sixth section is 150~210 ℃

temperature control in the second section is 100~200 ℃, temperature control in the seventh section is 140~200 ℃

temperature control in the third section is 150~210 ℃, temperature control in the eighth section is 100~190 ℃

temperature control in the fourth section is 150~210 ℃, temperature control in the ninth section is 90~200 ℃

temperature control in the fifth section is 150~210 ℃, temperature control in the head is 90~200 ℃

(4) high pressure water flow pelletizer and centrifugal drying, grading screen and automatic

III. introduction to main equipment:

1. Raw material processing equipment:

(1) pes tank: 2 × 200L（ φ six hundred × 700), three-layer structure: stainless steel liner, heat transfer oil heating jacket, wrapped with polyurethane rigid foam insulation, with frame stirring (rotating speed 30r.p.m, power 0.55kw) and precision shaft seal to ensure the air tightness of the tank. Equipped with feeding port, sight glass, vacuum and N2 port, minimum liquid level alarm device, heating power 2 × 4.5kw。

(2) MDI tank: 2 × 120L（ φ five hundred × 500), three-layer structure: stainless steel liner, heat transfer oil heating jacket, wrapped with polyurethane rigid foam insulation, with frame stirring (rotating speed 30r.p.m, power 0.55kw) and precision shaft seal to ensure the air tightness of the tank. Equipped with feeding port, sight glass, vacuum and N2 port, the lowest liquid level alarm is widely used in the industry, and the heating power is 2 × 4.5kw。

(3) BDO tank: 2 × 80L（ φ four hundred × 500), three-layer structure: stainless steel liner, heat transfer oil heating jacket, wrapped with polyurethane rigid foam insulation, with frame stirring (rotating speed 30r.p.m, power 0.55kw) and precision shaft seal to ensure the air tightness of the tank. Equipped with feeding port, sight glass, vacuum and N2 port, minimum liquid level alarm device, heating power (1+2) kW

(4) vacuum system:

① vacuum buffer tank: 80L（ φ four hundred × 500) stainless steel multilayer baffle type

② vacuum pump: 2x-15a (2.2kW)

(5) heating system: (a, B, C are set up three sets)

① heat transfer oil tank: 70L, heating power 4.5kw

② circulating oil pump: b-bb16 gear oil pump 0.75kw6p

2, TPU pouring machine:

total pouring volume: 1~2kg/min (1440~2880kg/d) design mixing ratio: a:b:c=100:40:10; Measurement error ≤± 0.5%

working temperature: material a: 100~120 ℃; Material B: 60~70 ℃; C material: 30~50 ℃, pouring head: 70~80 ℃

temperature error: ± 2 ℃, vacuum degree: 5~10mmhg

(1) metering pump composed of semiconductor molecules: high precision low-speed metering pump (pressure resistance 10MPa, temperature resistance 450 ℃), driven by high-precision gear reducer motor, and adjusted by imported frequency converter

a pump gj20 speed 30~200r p. M, power 0.75kw 4P, displacement 0.6~4kg/min

b pump gj9, speed 30~200r p. M, power 0.75kw 4P, displacement 0.3~1.8kg/min

c pump gj2.4, speed 30~200r p. M, power 0.75kw 4P, displacement 0.08~0.5kg/min

2) pouring head: three component high-temperature pouring head, which can mix evenly and produce no bubbles, mixing motor 1.5kw2p, rotating speed 3000~8000r p. M (variable frequency speed regulation)

(3) control and electrical appliances:

① digital display intelligent temperature controller is used to make the heating of filter, metering pump and pouring head reliable and accurate

② full digital precision instruments are used for pressure, speed (ratio), etc

③ imported components are used for electrical appliances

3. Twin screw reaction extruder: (for users' reference only when selecting the machine)

lsf-75 (nine stage temperature regulation simplified) (jb/t)

nominal diameter of screw: φ 72. The center distance is 60, the length diameter ratio of the screw is 48, and the gap between the screw and the cylinder is ≤ 0.02mm

the maximum speed of the screw is 400r p. M, (the screw speed should be based on the material staying in the screw barrel for 1~2min) the main motor power is 75kW, and the maximum output is 200kg/h