Interlock Fabric: Structure, Properties, and Applications

Interlock fabric is a type of double-knit fabric known for its smooth texture, excellent durability, and balanced stretch. As one of the most versatile knit fabrics, it is widely used in apparel, sportswear, home textiles, and technical applications. Its unique structure allows it to offer the comfort and elasticity of single knits while maintaining superior dimensional stability and opacity.

In this article, we’ll explore the construction, key properties, and applications of interlock fabric, and examine why it continues to be a preferred choice in both fashion and functional textiles.

What is Interlock Fabric?
Interlock fabric is a variety of weft-knit textile, produced using two sets of needles on a circular knitting machine. Unlike single jersey knits that use one needle bed, interlock fabric is made with two needle beds working simultaneously, creating a double-faced fabric where the front and back surfaces look identical.

The name “interlock” comes from the way the loops from the front and back knit structures interlock with each other. This results in a fabric that is:

Thicker and heavier than single jersey
More stable with minimal curling at the edges
Smoother on both sides
More opaque and structured

Key Characteristics of Interlock Fabric
1. Smooth Surface on Both Sides
Because of the double-knit construction, interlock fabric has two right sides, making it extremely soft and smooth on both faces—ideal for garments worn close to the skin.

2. High Stretch and Recovery
Although interlock fabric is less stretchy than rib knits, it offers a moderate amount of four-way stretch with excellent recovery, providing comfort without losing shape over time.

3. Good Opacity
Interlock is denser than jersey, which means it’s not see-through even in lighter colors, making it a good choice for t-shirts, leggings, and dresses.

4. Stable and Durable
The interlocking knit structure resists distortion, pilling, and edge curling. It holds its shape well even after repeated washing and wear.

5. Breathable and Absorbent
Typically made from cotton, cotton blends, or synthetic fibers like polyester and rayon, interlock fabric balances breathability with moisture absorption, depending on the yarn used.

6. Easy to Sew
Interlock’s stability and clean edges make it one of the easiest knit fabrics to handle for sewing and garment construction.

Common Fiber Types Used in Interlock Fabric
100% Cotton: Soft, breathable, ideal for baby clothing, loungewear, and casual wear.

Cotton-Polyester Blend: Enhances durability and wrinkle resistance while maintaining softness.

Rayon Blends: Add drape and silky feel, often used in fashion garments.

Spandex-Enhanced: Provides extra stretch for activewear or fitted garments.

Manufacturing and Finishing
Interlock fabric is typically knitted on circular knitting machines using fine-gauge needles for a tight, smooth finish. After knitting, the fabric can undergo various finishing treatments, such as:
Brushing for added softness
Peaching for a suede-like feel
Moisture-wicking or antimicrobial finishes for activewear
Printing or dyeing for fashion use

Applications of Interlock Fabric
1. Apparel
T-Shirts and Polo Shirts: Comfortable, smooth, and opaque—ideal for everyday wear.

Activewear: With spandex blends, interlock is used for leggings, yoga tops, and training gear.

Undergarments and Sleepwear: Soft against the skin and breathable.

Baby Clothing: Especially popular for onesies, rompers, and baby blankets due to its gentle feel.

Dresses and Tunics: Holds structure better than single jersey but remains comfortable.

2. Home Textiles
Bedding and Pillowcases: Soft and breathable interlock fabric is used in fitted sheets and pillow covers.

Blankets and Throws: Especially those requiring a smooth yet warm surface.

3. Corporate and Uniform Wear
Workwear Polos: Often made from cotton-polyester interlock for a clean look, color retention, and ease of maintenance.

4. Technical and Industrial Use
Interlock fabric may be used as a base layer in laminated fabrics or as part of multi-layer functional textiles, such as in protective gear or moisture management systems.

Advantages Over Other Knit Fabrics

Care and Maintenance
Interlock fabric is generally easy to care for, though recommendations may vary depending on the fiber content:

Machine washable in cold or warm water
Low tumble dry to reduce shrinkage
Cool iron if needed (avoid high heat with synthetic blends)
Avoid bleach to preserve color and fabric integrity
For spandex-blend interlock, avoid fabric softeners as they may degrade the elastic fibers over time.

Conclusion
Interlock fabric combines comfort, structure, and versatility, making it a valuable material in the world of knit textiles. Its double-knit structure provides a stable and smooth fabric suitable for everything from everyday clothing and athletic wear to baby apparel and home textiles. With the right fiber blend and finish, interlock fabric adapts to a wide variety of functional and aesthetic requirements.

Whether you're a designer, manufacturer, or consumer, understanding the properties and potential of interlock fabric can help you make better material choices for your products or wardrobe.