Sea-island fiber, also known as super-conjugate fiber or butterfly polyester yarn, is formed by a core component dispersed in another polymer in a longitudinally continuous way. Polymer material forms the core part, which is also called the island phase or dispersed phase. Another polymer is called sea component, sea phase, or continuous phase. Because original dispersed phase fiber presents as an island state in the fiber section, it is called sea-island fiber.

Development History of Sea-island Fiber

Sea-island fiber was first developed in the early 1970s and was mainly used to produce suede-like fabrics.

In 1970, Japan’s Toray Company first introduced the artificial deerskin fabric “ECSAINA” made of soluble superfine fibers (sea-island superfine fibers) to the market, marking the beginning of industrial production of sea-island composite superfine fibers.

In 1972, Japan’s Kanebo Corporation also successfully developed a dissolvable polyester-nylon synthetic fiber with the trade name “BELIMA”.

In recent years, Japan, South Korea, Chinese Taiwan, the United States, and Italy have carried out development and production. Sea-island fibers in Japan, the United States, and Europe have been industrialized with relatively complete technology. South Korea and Chinese Taiwan also have some representative products.

In the early 1970s, our country began to study the sea-island synthetic superfine fiber, but it did not make any substantial progress until the 1990s. And it was added into the national science and technology development plan during the “seventh five-year plan”.

Sea-island Fiber Production Technology

There are two production methods for sea-island fiber, composite spinning method, and blended spinning method. The island component generally uses PET and PA, and the sea component mostly uses COPET, PVA, PE and PS, etc.

According to the difference of soluble components as island phase or sea phase in the fiber, composite island fiber is divided into fixed island type and non-fixed island type.

Fixed and Non fixed island type fiber

Fixed and Non-fixed island type fiber

Hollow fiber is obtained after the island part is dissolved from fixed island type fiber, while sea-island ultrafine fiber is obtained after the sea part is dissolved from non-fixed type.

hollow fiber and ultrafine fiber

hollow fiber &ultrafine fiber

Take the alkali-soluble modified COPET/PA6 sea-island composite ultra-fine short fiber as an example. COPET/PA6 method is conducted with COPET as the “sea” component and PA6 as the “island” component through conjugate composite spinning technology.

Characteristic of Sea-island Fiber

Compared with normal fiber, sea-island fiber enjoys exclusively good characteristics.

1. The sea-island fiber has a very small size, which makes the fabric soft, smooth and perfect in comfort. It can produce a fabric with high density, moisture absorption, water repellency, and unique aesthetics and fashion style. At the same time, a multi-layer structure can be formed on the surface of the fabric, so that the reflective point of the fabric is small, the luster and color are soft, and the appearance is plump, fine, and clean.

2. There are many and dense voids between fibers, and its capillary action can be used to make the fabric have better moisture and oil absorption capacity. In addition, by appropriately changing the gap between the fibers, it can be woven into a sea-island high-density fabric with a gap of only 0.2μm~10μm, which has excellent waterproof and vapor permeability properties. The micro-porous structure between the fabrics allows more static air in the fabrics, so better heat insulation can be obtained.

3. The flexural rigidity of the fiber is small, which makes the fabric easy to obtain an elegant and chic effect. The core layer is high-shrinkage silk, which gives the fabric excellent drape and visual comfort.

4. The fiber has a large specific surface area and many voids, which make the fabric have strong dust absorption, decontamination, and filtration. The fiber is slender and soft, which can protect the cleaned items from injury. It is a high-performance cleaning product.

Application of Sea-island Fiber

Fashion Fabric

Because the number of monofilaments in superfine fiber is more than that in the ordinary filament, the surface area of the fiber is larger, and the air permeability of the fabric is increased. After non-woven weaving, the non-woven fabric is used as the base one. Then after polishing and sand washing, the fabric is made into supernatural fabric. Because its breathability and softness are superior to natural textiles, chemical fiber fabric has gone into the high-end fashion field.

Artificial Leather

The PU leather with fine fiber as the base fabric not only has a microstructure similar to natural leather, good moisture permeability, dimensional stability, and various fastnesses better than natural leather but also avoids natural products due to the type, size, and location of animals Large unevenness and small effective utilization rate caused by the difference. In addition, PU leather overcomes the tendency of natural leather to be damp, moldy, and smelly due to its own protein fiber, which is very popular among consumers.

High-performance wipes

Due to its small size, large specific surface area, good softness, and strong water and dirt absorption capacity, ultra-fine fibers will not only damage the substrate after wiping the thin oil film but also have a clean wipe result without leaving residues. And it can be used as a High-performance wipe, such as advanced lens wipes.