May 27, 2024 Longchang Chemical

1、Typical formula and performance of block polyether type PU soft foam

Polyether ternary alcohol 100pbw

TDI80/20 46.0pbw

Organic tin catalyst 0.4pbw

Tertiary amine catalyst 0.2pbw

Organosilicon foam stabiliser 1.0pbw

Water 3.6pbw

Auxiliary foaming agent 0~12pbw



Foam density, kg/m3 22.4

Tensile strength, kpa 96.3

Elongation, % 220

Tear strength, N/m 385

Compression set, 50% 6

90% 6

Cavity load, kg


Deformation 25% 13.6

65% 25.6

Ball rebound, % 38


In recent years, in order to meet the needs of the market, some enterprises tend to produce low-density (10kg/m3) or so foam, in the production of ultra-low-density soft foam, not simply increase the blowing agent and auxiliary blowing agent can be done, but also must have a relatively high stability of silicone surfactants and catalysts to cooperate.


Production of low density ultra-low density soft foam reference formula:


Name Medium density Low density Ultra-low density
Continuous box continuous box box box box
Polyether polyol 100 100 100 100 100 100
Water 3.0 3.0 4.5 5.5 6.6
A-33 catalyst 0.2 0.2 0.2 0.2 0.25 0.18
Silicon surfactant B-8110 1.0 1.2 1.1 1.9 3.8
Stannous octoate 0.25 0.28 0.35 0.36 0.40
Foaming aid 7.5 7.5 12.5 15.0 34.0
TDI80/20 41.4 44.0 56.0 73.0 103.0
Density, kg/m3 23.0 23.0 16.5 14.0 8.0

Cylindrical foam formulation:

EO/PO type polyether polyol (OH:56) 100pbw

Water 6.43pbw

MC blowing agent 52.5pbw

Silicon surfactant L-628 6.50pbw

Catalyst A230 0.44pbw

Stannous octoate D19 0.85pbw

TDI80/20 Index 0.99

Dosage 139pbw

Foam density, kg/m3 7.5


2、Liquid CO2 auxiliary blowing agent to make low density foam

Polyether ternary alcohol (Mn3000) 100 100

Water 4.9 5.2

Liquid CO2 2.5 3.3

Silicon surfactant L631 1.5 1.75


Amine catalyst A133 0.28 0.30

Stannous octoate 0.14 0.17

Flame retardant DE60F 0 14

TDI80/20 Index 110 112

Foam density, kg/m3 16 16


Typical machine hair formulations are as follows:

Polyether ternary alcohol (Mn3000) 100pbw

Water 4.0pbw

LCO2 4.0~5.5pbw

Catalyst A33 0.25pbw

Silicon surfactant SC155 1.35pbw

Stannous octoate D19 0.20pbw

TDI80/20 index 110

Foam density, kg/m3 14.0~16.5


3、Full MDI low density polyurethane flexible foam

Flexible PU moulded foam is widely used in the production of car seat cushion. Reducing density without affecting physical properties is the goal of development.


Highly active polyether (OH:26~30mgKOH/g) 80pbw

Polymer polyol (OH:23~27mgKOH/g) 20pbw

Crosslinking agent 0~3pbw

Water 4.0pbw

Amine catalyst A-33 2.8pbw

Silicone oil surfactant B8716 1.0pbw

MDI index 90pbw



Foam centre density 34.5kg/m3

Hardness ILD25% 15.0kg/314cm2

Tear strength 0.8kg/cm

Tensile strength 1.34kg/cm2

Elongation 120%

Resilience 62

Permanent compression set (dry) 5.0%

(Wet) 13.5


4、Low density, full MDI environmentally friendly car seat cushions

Adopting pure MDI homologue: M50–that is, 4,4‘MDI 50% 2,4’MDI 50% of the product, can be room temperature foaming, improve the fluidity, reduce the density of the product, reduce the weight of the vehicle, is a very promising product:


Highly active polyether polyol (OH:28mgKOH/g) 95pbw

310 additives* 5pbw

Dabco 33LV 0.3pbw

Dabco 8154 0.7pbw

Silicon surfactant B4113 0.6pbw

A-1 0.1pbw

Water 3.5pbw

M50 50pbw

Isocyanate index 88


Physical properties:

Drawing time(s) 62

Rise time(s) 98

Free bubble density, kg/m3 32.7

Compression load deflection, kpa:40% 1.5

Elongation, % 180

Tear strength, N/m 220

Note: *310 additives: we have sold, is a special chain growth agent.


5、High resilience, ride comfort PU foam

Recently, the market demand foam seat cushion physical properties remain unchanged, but people sit in the car for a long time without fatigue, no motion sickness high-quality seat cushion . After research, the internal organs of the human body, especially the stomach and other organs in the frequency of about 6Hz, if caused by resonance will cause regurgitation, vomiting and other phenomena.

Generally speaking, the vibration transmissibility of high resilience foam at 6Hz is 1.1~1.3, that is to say, when the vehicle is running, not only does it not weaken but also increase, and some formulated products can be vibration damping to 0.8~0.9. Now we recommend a product formula, whose vibration transmissibility at 6Hz is 0.5~0.55 level.


Highly active polyether polyol (Mn6000) 100pbw

Silicon surfactant, SRX-274C 1.0pbw

Tertiary Amine Catalyst, Minico L-1020 0.4pbw

Tertiary amine catalyst, Minico TMDA 0.15pbw

Water 3.6pbw

Isocyanate prepolymer (NCO%=29.7%)


Physical Properties:

Overall density, kg/m3 48.0

25%ILD, kg/314cm2 19.9

Resilience, % 74

50% compression strength, (dry) 1.9

(wet) 2.5

6Hz vibration transmissibility 0.55


6、Slow rebound or viscoelastic foam

The so-called slow rebound PU foam refers to the deformation of the foam by external forces, the foam is not immediately return to its original shape, but slow recovery, and no residual surface deformation of the foam. It has excellent cushioning, sound insulation, sealing and other properties. It can be used in car engine noise prevention, carpet backing, children’s toys and medical pillows.

Example formula:

Highly active polyether (OH34) 40~60pbw

Polymer polyether (OH28) 60~40 pbw

Cross-bonding agent ZY-108* 80~100 pbw

L-580 1.5 pbw

Catalyst 1.8~2.5 pbw

Water 1.6~2.2 pbw

Isocyanate index** 1.05 pbw

Note: *ZY-108, compound of multifunctional low molecular weight polyether

**PM-200 and liquefied MDI-100 are Wanhua products.

Physical properties:

Foam density, kg/m3 150~165

Hardness, Shore A 18~15

Tear strength, kN/m 0.87~0.76

Elongation, % 90~130

Resilience, % 9~7

Recovery time, sec 7~10


7、Flexural fatigue resistance million times polyether type self-skinned microcellular foam

The foam can be applied to PU shoe sole and steering wheel


Daltocel®F-435 31.64 pbw

Arcol®34-28 10.0 pbw

Daltocel®F-481 44.72 pbw

Arcol®2580 3.0 pbw

Glycol 6.0 pbw

Catalyst Dabco EG 1.8 pbw

A-1 0.3 pbw

Dabco®1027 0.3 pbw

Silicon surfactant DC-193 0.3 pbw

L1 412T 1.5 pbw

Water 0.44 pbw

Modified MDI

Suprasec®2433 71 pbw


Physical properties:

Foam density: around 0.5 g∕cm3

β-belt deflection, KCS between 35 and 50, very good


8、Flame-retardant, low smoke emission, high resilience foam

With the rapid development of the national economy, various departments have higher and higher requirements for the flame-retardant foam products, especially aviation, cars, high-speed buses, household sofas and so on, all of which require flame-retardant, low fume, low smoke toxicity or non-toxicity foam products.

The authors and colleagues for the above situation, developed a flame retardant grade (oxygen index 28 ~ 30%), smoke density is very low (international is 74, this product is only 50 or so), and the foam rebound unchanged, the flame in the production of white smoke.

Example formula:

YB-3081 flame retardant polyether 50 pbw

Highly active polyether (OH34) 50 pbw

Organosilicon surfactant B 8681 0.8~1.0 pbw

Water 2.4~2.6 pbw

DEOA 1.5~3 pbw

Catalyst A-1 etc. 0.6~1.1 pbw

Isocyanate index 1.05


Physical properties:

Foam density,kg/m3 ≥50

Compression strength,kPa 5.5

Tensile strength,kPa 124

Resilience, % ≥60

Compression deformation, 75% ≤8

Oxygen index, OI% ≥ 28

Smoke density ≤50


9、Water as blowing agent, environmentally friendly integral skin foam

Foreign countries have been completely banned HCFC-141b blowing agent, CP system blowing agent is flammable, HFC-245fa, HFC-365mfc system blowing agent price is high, it is difficult to accept, the only way out is to synthesise environmentally friendly integral skin foam with water as blowing agent. In the past, domestic and foreign PU workers, only pay attention to the polyether and isocyanate modification, so the foam made of the surface layer is not clear, high density.

Now recommended a group of formulations, which are characterised by:

The basic polyether polyol remains unchanged, using the conventional Mn5000 or 6000.
The isocyanate remains unchanged, and C-MDI, PAPI or modified MDI can be used.
The use of special additives SH-140, can be solved. –
Basic formula:

Highly active polyether terpolyol Mn5000 65pbw
SH-140* 35pbw
Chain growth agent: 1,4-butanediol 5pbw
Crosslinking agent: Glycerol 7pbw
Pore opener: K-6530 0.2~0.5pbw
Catalyst A-2 1.2~1.3pbw
Colour paste moderate amount
Water 5pbw
MR-200 45pbw
Note: *SH-140 is our product.


Physical properties:

Overall density of foam 340~350kg/m3

Product: Smooth surface, clear crust, low density.

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