How should the polyester fiber specifications be for bedding pillows? (HCS TDS for pillow use)

The quality of a pillow begins with the selection of its filling fiber.

For bedding manufacturers, brand buyers, and material developers, various factors such as softness, resilience, breathability, and hygiene must be taken into account. Among the many options, Polyester Staple Fiber (PSF) is widely adopted in the bedding industry due to its cost-effectiveness and consistent quality.

In this post, we will outline the recommended specifications of polyester fiber best suited for pillow filling.

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What Specifications of Polyester Fiber Are Best Suited for Pillows?

Pillow filling fiber shouldn't be just soft.

It needs to support the head for extended periods without flattening, offer excellent resilience, and ensure hygiene and ease of processing. Based on these requirements, the recommended fiber specifications are as follows:

Item	Recommended Specification
Type	Hollow Conjugated Fiber
Denier	6D ~ 7D
Cut Length	64 mm
Crimp per Inch (CPI)	5 ~ 7 CPI
Tenacity	≥ 4.0 g/d
Elongation	30 ~ 50%
Silicone Finish	Applied
Oil Content	0.2 ~ 0.3%
Raw Material	Virgin PET or GRS Recycled PET

Denier : For pillow filling, polyester fibers in the range of 6D to 7D are considered ideal.

Fibers that are too fine (e.g., 3D) tend to lack volume and may result in pillows that flatten easily.

Fibers that are too thick (e.g., 15D) can feel stiff and uncomfortable.

Crimp per Inch (CPI) : Crimp per inch indicates the number of waves or crimps in a fiber per inch (approximately 2.54 cm). It quantifies how much the fiber is curled or waved.

For pillow applications, moderate elasticity and recovery are essential. A crimp level of 5 to 7 CPI is typically recommended for optimal resilience and softness.

Tenacity : Tenacity measures the strength of a fiber, or how much force it can endure before breaking. It is usually expressed in grams per denier (g/d) or centinewtons per tex (cN/tex).

For example, if a 7D fiber breaks under 28g of force, its tenacity is 28g ÷ 7D = 4.0 g/d. For pillow use, where softness and durability must coexist, a tenacity of 3.5 to 5.0 g/d is ideal.

Elongation : Elongation refers to the extent to which a fiber can stretch before breaking. For instance, if a 100mm fiber stretches to 140mm before snapping, its elongation is 40%.

In pillow applications: Too low elongation makes the fiber stiff and less cushiony. Too high elongation reduces shape recovery and can make the pillow feel too floppy. An elongation range of 30% to 50% is generally suitable for pillow fibers.

Silicone Finish : Silicone finish involves coating polyester fibers with a thin layer of silicone oil (or emulsion) to improve: Softness, Lubrication, Processability.

This treatment helps prevent tangling and clogging in filling machines, enhances fiber smoothness, and improves bounce-back performance, resulting in a fluffier and longer-lasting pillow.

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Why Hollow Conjugated Fiber?

The hollow structure creates an air layer inside the fiber, enhancing lightness, thermal insulation, and resilience.

The conjugated structure gives the fiber a natural spring effect, resulting in a plush and voluminous cushion feel.

When silicone treatment is applied, the texture becomes silky-soft, and fiber entanglement during carding or filling processes is reduced, improving production efficiency.

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Since bedding pillows are products used daily by customers, the quality of the fiber becomes a key differentiating factor.

It is essential to choose PSF (Polyester Staple Fiber) with the right combination of denier (D), fiber length, crimp level, and silicone finish.

DK FIBER can reliably supply polyester staple fibers optimized for pillow filling.We also accommodate OEM custom specifications and requests for GRS-certified materials.Feel free to contact us anytime for samples or quotations.