An Adhesives Sigma Mixer (also known as a Sigma Blade Mixer, Z-Blade Kneader, or Double-Arm Kneader) is a heavy-duty industrial mixing machine specifically designed for processing high-viscosity, sticky, and semi-solid materials. It is widely used in the adhesives industry for manufacturing products like hot melt adhesives, sealants, silicones, caulks, putties, and rubber compounds. The mixer’s robust construction and unique blade design make it ideal for intensive kneading and shearing actions, ensuring uniform blending of raw materials such as resins, polymers, fillers, and curing agents.
Adhesives Sigma Mixer Video
Key Features and Design
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Blade Configuration: The mixer features two counter-rotating, sigma-shaped (Z-like) blades mounted in a horizontal, trough-like mixing chamber. These blades can be tangential (running parallel for high shear) or intermeshing (overlapping for gentler kneading), depending on the viscosity of the adhesive. The blades rotate at differential speeds (typically low tip speeds of 60-70 meters per minute) to pull, shear, compress, fold, and squeeze the material against the trough walls, saddle, and each other.
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Capacity and Versatility: Handles batch sizes from lab-scale (e.g., 5-50 liters) to industrial volumes (up to several cubic meters), with fill volumes of 40-65% of the trough capacity. It processes materials ranging from dry powders to stiff pastes exceeding 2 million centipoise viscosity.
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Construction Materials: Typically made from stainless steel, with options for hardened coatings, Monel, nickel, or other alloys to resist abrasion from fillers like pigments or silica. Blades and trough can be lined for corrosion resistance in acidic or reactive adhesive formulations.
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Additional Capabilities: Many models include heating/cooling jackets for temperature control (essential for melting hot melt adhesives), vacuum systems to remove air bubbles and volatiles, and discharge options like tilting troughs or extrusion screws for easy unloading.
Working Principle
The sigma blades create a tangential or intermeshing action that transfers material from one blade to the other, generating high shear forces and thorough kneading. This results in:
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Uniform dispersion of ingredients, preventing agglomeration.
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Efficient incorporation of high-viscosity components like EVA resins or butyl rubber.
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Reduced mixing times while achieving up to 99% homogeneity.
Power consumption is higher than standard mixers (45-75 kW/m³), but the design ensures noise-free, vibration-resistant operation when mounted on sturdy steel stands.
Benefits
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Efficiency: Shortens processing time and improves product consistency, leading to reliable bonding performance and stability.
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Scalability: Suitable for R&D to full production, with customizable options like vacuum drying for bubble-free adhesives.
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Durability: Handles abrasive materials without frequent maintenance, making it cost-effective for continuous operations.
Salient Features of Sigma Mixer Machine
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Available in Stainless Steel 316, Stainless Steel 304 and Mild Steel materials.
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Stainless Steel polish to matt & mirror finish as per customer’s requirements.
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Mild Steel finish with one coat of red oxide and two coats of epoxy paint.
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Discharge option of hand wheel operated (manual) or hydraulic operated (automatic) offered.
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Jacket for heating or cooling application can be offered.
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Mineral wool insulation with cladding on jacket.
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Tangential designed ‘Z’ blades offered for uniform mixing.
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PTFE made shaft sealing provided for food grade compatibility.
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Minimum gap between trough inner shell & blades removes possibility of sticking product.
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On demand Spray system, vacuum system
Optional Features/Accessories of Sigma Mixer
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Liquid Spray System
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Vacuum System
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Blades Cooling Arrangement
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Screw System
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Automatic Valve Discharge System
Process Operation of Adhesives Sigma Mixer
In Sigma mixer tangential action of mixing and kneading obtained by ‘Z’ type (SIGMA) shaped kneading blades, which rotates very accurately at different speed towards each other causing product to be transferred from one end to another end. Discharge of the finished product is achieved by tilting the container or through the valves at the bottom or by means of an extrusion screw beside the container.
The mixing action is a combination of bulk movement, stretching, folding, dividing, and recombining of the material. The shearing & tearing action of the material against blades and the side walls causes size reduction of the solids. After the time period required for sterilizing the batch has elapsed, the heating circuit shuts of the pneumatics damper (exhaust) opens and cooling operation commences.
In the tangential design, the blades rotate in the trough meeting tangentially. The front blade generally rotates faster than the rear blade usually in the ratio of 3:2. Tangential blades are generally used for material of higher viscosities such as adhesives, rubber compounds, flush colors, dyes, and pigments.
In the overlapping design, the blades overlap above the saddle of the container. Due to the overlapping action, it is necessary that the relative position of the two blades is unchanged, and as a result, both the blades rotate at the same speed. Materials that flow freely or creep down into the blades are mixed using the overlapping blade action. This design offers a faster interchange of material from one blade compartment of the mixer to the other. Overlapping blade action is used for materials of lighter viscosities such as carbon pastes, clay coating, creams, and ointments. The overlapping blade produces a lower kneading and shearing compared to the tangential blade action.
Technical Specification of Sigma Mixer
| Model | Capacity – Liters | Motor (H.P.) | ||
| Working Capacity approx. | Gross Capacity approx. | General | Heavy Duty | |
| ASM – 50 | 50 Liters | 80 Liters | 5 H.P. | 7.5 H.P. |
| ASM – 75 | 75 Liters | 110 Liters | 7.5 H.P. | 10 H.P. |
| ASM – 100 | 100 Liters | 150 Liters | 10 H.P. | 15 H.P. |
| ASM – 150 | 150 Liters | 200 Liters | 15 H.P. | 20 H.P. |
| ASM – 200 | 200 Liters | 300 Liters | 20 H.P. | 25 H.P. |
| ASM – 400 | 400 Liters | 550 Liters | 30 H.P. | 40 H.P. |
| ASM – 500 | 500 Liters | 750 Liters | 40 H.P. | 50 H.P. |
| ASM – 750 | 750 Liters | 1150 Liters | 50 H.P. | 60 H.P. |
| ASM – 1000 | 1000 Liters | 1500 Liters | 60 H.P. | 70 H.P. |
| ASM – 1500 | 1500 Liters | 2100 Liters | 75 H.P. | 80 H.P. |
| ASM – 2000 | 2000 Liters | 2600 Liters | 80 H.P. | 90 H.P. |
| ASM – 3000 | 3000 Liters | 3800 Liters | 100 H.P. | 120 H.P. |
* Power voltage can be adjusted as per customer’s domestic power voltage requirements.
* Rights of technical improvements & modification reserved.
* Illustrations & dimensions are shown for information purpose only.
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