Rigid foam leveling agent (hereinafter referred to as “silicone oil”) model selection and dosage definition is of great importance, it is directly related to the final product of the foam pore structure, shrinkage resistance, insulation and other actual performance advantages and disadvantages.
Experimental object
Conventional in the use of rigid foam silicone oil as a reference A, compared to the unknown performance of rigid foam silicone oil B, C, D, E, etc.
Test apparatus
(Here only highlight the parts that are different from the conventional test)
1, variable-speed hand drill: about 300w, available knob gear to adjust the speed;
2, about 100ml size of disposable transparent plastic drinking cup: to be slightly harder, so as not to stir when holding deformation difficult to pinch.
Blank master batch preparation example
A, high moisture, low density type manual slow material
Polyether 4110：100
Water: 1.8
Cyclohexylamine: 1.0~2.0 (depending on the ambient temperature and material temperature control)
141B：25
Second, low moisture, high density type manual slow material
Polyether 4110：100
Water: 0.5
Cyclohexylamine: 1.0~2.0 (depending on ambient temperature and material temperature control)
141B：7
The total amount of the above blank material preparation depends on the number of silicone oil types to be compared to the whole n times enlarged. Overall shake well and then divide into n equal parts.
Foam]
A. High moisture, low silicone oil, low density type manual slow material
Add 0.5 parts of A, B, C and D silicone oil to n equal parts of blank material, shake well and let it stand to see its compatibility and transparency.
Adjust the speed of variable speed hand drill to the right gear: make sure the stirring speed is “medium slow”, never allow high shear fast gear stirring.
Within 20 minutes, each component with 0.5 parts of silicone oil will be foamed at the same speed, the same ratio (about 12g white material + 12g black material) and the same mixing time.
Reminder: Don’t break the mushroom head. After foaming and shaping, you can only make marks at the bottom of the cup separately in order to be objective and fair when comparing.
Second, low moisture, low silicone oil, high-density manual slow material
Operation with (i), about 20 grams of white material + 20 grams of black material
C. High moisture, high silicone oil, low density hand-made slow material
Test (i) in each section of the remaining white material in proportion to the amount of their respective silicone oil to 1.0 parts, and then the same conditions foaming
Fourth, low moisture, high silicone oil, high density type manual slow material
The remaining white materials in test (ii) will be proportionally increased to 1.0 parts of their respective silicone oil, and then the same conditions foaming
Comparison, analysis]
Test one of the foam mixed together with the naked eye to distinguish the apparent advantages and disadvantages of the bubble hole (bubble hole density, uniformity), and then look at the bottom to determine the ranking of these silicone oil;
Test three of the foam mixed together with the naked eye to distinguish the apparent pore superiority (pore density, uniformity), and then look at the bottom to determine the ranking of these silicone oils;
And then one, three experiments in the same silicone oil type of different amounts of foam body put together to compare, to see the amount of silicone oil to increase the fine density of pores, uniformity has improved significantly
The same between the second and fourth
If necessary, a sharp cutting edge can be used to compare the internal pores
Special note]
Usually, the silicone oil with good bubble pore under slow stirring has better performance under high shear stirring, especially the combination of materials to resist “abnormal fluctuation of process parameters during injection molding” (such as: power supply voltage fluctuations, power frequency abnormalities, minor blockage, material viscosity abnormalities) ability is better.
