As a personal hygiene product, diapers are of great help to the healthy growth of infants and young children, and to the health and life of the elderly. It is an indispensable product for personal care in the two groups. Since the advent of baby diapers in the 1950s, the industry has undergone many technological developments, industrial upgrades and product updates, with more refined structures and more complete functions. Its main user group has expanded from infants to adults, and has maintained a market penetration rate of 80%-90% in developed countries such as Europe and the United States. The rise in China is still relatively short, and the penetration rate has much room for improvement.
The output of China's diapers in 2017 was 35.060 billion pieces, and the output of China's diapers in 2018 was approximately 38.140 billion pieces.
In recent years, the production and sales volume of China's diaper industry has remained at a high level. In 2018, China's diaper output was 38.140 billion pieces, and factory sales were 37.364 billion pieces. The production and sales rate of China's diaper manufacturing industry was 97.97%.
In the market segment of China's diaper product output, baby diapers are mainly produced. In 2018, the production of baby diapers accounted for 88.07%, and the production of adult diapers accounted for 11.93%.
China's diapers sales increased from 25.7 billion yuan to 49.2 billion yuan in 2013-2016, with a CAGR of 12.0%; global sales increased from 34.8 billion US dollars to 42.3 billion US dollars, with a CAGR of 6.7%. International demand for diapers is huge.
What is a diaper?
Diapers are a kind of disposable personal hygiene care products and a subdivision product of paper diapers. The appearance of the product is "trouser-shaped", so it is called paper diapers.（Suntech Diaper machine）
Diapers generally consist of three main parts: surface covering layer, absorbent core layer and base fabric. The diapers on the market are basically a non-woven surface layer. The breathable non-woven fabric can increase the degree of air permeability inside the diaper. Water vapor can circulate outside the diaper to discharge moisture and heat in time, effectively reducing the chance of eczema, and it is soft and comfortable. Does not irritate the skin.
1. Surface coating
The surface covering layer is close to the baby's body, which can promote the rapid penetration of urine and effectively prevent back seepage, and keep the surface of the diaper dry. The material is generally non-woven, which has the function of penetration and isolation.
2. Absorb the core layer
This layer is mainly able to capture and quickly absorb urine, disperse urine or diffuse it into the entire core layer through capillary action, and finally absorb and store urine. The absorbent core layer of diapers in the domestic market is mainly composed of pure wood pulp (fluff pulp) and super absorbent resin (SAP) to form a layered structure for absorption.
3. Bottom cloth part
Many European and American diaper bottom fabrics use more comfortable non-woven fabrics. The function of the leak-proof bottom film is to prevent penetration and avoid contamination of clothing. Some products use a breathable bottom film to enhance the breathability of the diaper.
The key to the difference of diapers
The key to the quality of diapers mainly depends on the water absorption of the absorbent core and the skin affinity of the base fabric.
1. Water-absorbing core layer:
The core is the core part of the diaper. Whether it leaks urine depends on this. There are 2 kinds of common cores on the market: fluff pulp + SAP (polymer absorbent resin), fluffy cotton + SAP.
No matter what kind of core, SAP is inseparable. Polymer water-absorbing resin (SAP) is a typical functional polymer material. It can absorb hundreds or even thousands of times its own weight of water, and has a strong water retention capacity, so it is also known as super water-absorbing agent or high water-retaining agent. In terms of chemical structure, super absorbent resin is a low cross-linking or partially crystalline polymer with many hydrophilic groups. The sanitary field is mainly used as raw material for sanitary napkins and diapers. SAP can grow flowers after absorbing water and swelling.
Water absorption principle: sodium polyacrylate → bridging into a network structure
The internal ion concentration is higher than the external one, causing osmotic pressure. SAP has a three-dimensional cross-linking bridge, which can inhibit the phenomenon of expansion, that is, produce the water absorption capacity of super absorbent resin.
(1) Fluff pulp + SAP:
Fluff pulp is wood pulp and straw pulp after bleaching and extraction of organic solvents. It is a kind of pulp used as a water-absorbing medium for the production of various sanitary products (such as sanitary napkins, baby diapers, hospital mattresses, etc.). It is a kind of pulp. There are too many grades of this quality. Nowadays, bleaching technology can easily produce inferior pulp.
The general requirements are good water absorption and rapid diffusion. The fluff pulp fiber needs to have high whiteness, soft fiber, certain elasticity and good core pad integrity, and it must meet the specified sanitary indicators. The raw materials of fluff pulp are divided into coniferous wood, hardwood and non-wood.
High-quality fluff pulp is made of plant fibers, that is, raw wood pulp, and is not a so-called secondary fiber. But it is not ruled out that some inferior products use substandard fluff pulp to make sanitary products. The fluff pulp absorbs water fast, but the core is thick, and the fluff pulp has less SAP and less liquid absorption. Moreover, it is easy to generate faults and affect the secondary absorption. Slightly poor quality will increase the frequency of changing diapers.
(2) Fluffy cotton + SAP:
Fluffy cotton, also known as fiber synthetic styling flakes or spray cotton, is a new type of winter filling material. Fluffy cotton is a kind of non-woven fabric, which is commonly referred to as space cotton or vacuum cotton. It is made of natural cotton fiber, man-made fiber or synthetic fiber through stretching, carding, spraying, baking and curing.
In winter, some cotton clothes and quilts use fluffy cotton as filling. Fluffy cotton has the properties of fluffy, high compression resilience, resistance to dry and wet washing, light weight and warmth.
The material is impassable, and the water absorption of fluffy cotton is also different. The fluffy cotton in the diaper core is easy to be fluffy and breathable, and it can also divert liquid, and it is not easy to break up. Fluffy cotton is not just the carrier of SAP, it can be more breathable after being fluffy, while fluff pulp does not have the characteristics of fluffy cotton. Therefore, whether the diaper of the fluffy cotton core is wet or not, customers will pinch and then check the thickness, while the thickness of the fluff pulp does not change much.
(3) Comparison of two cores:
The fluff pulp core body absorbs water quickly, but the problem of lump and fault remains to be solved.
The fluffy cotton core solves the problem of lumps and faults, but the amount of the core is different. Some pursue a thin core with less use and less liquid absorption.
2. Breathable bottom film
There are three common materials for the bottom film of diapers: PE breathable film (the bottom film of Pampers is a direct PE film), PE film + soft non-woven fabric, soft bottom film + hot air non-woven fabric.
(1) Breathable PE film:
The breathable membrane is an environmentally friendly, breathable (steam) and water-proof (liquid, bacteria, dust) functional material. The emergence of microporous breathable membranes has a history of more than 20 years, and has developed rapidly in the past 10 years. The main purpose of PE breathable bottom film is to prevent urine leakage.
Polyolefin breathable membranes are made by adding inert fillers to PE or PP carriers, forming membranes and stretching. Used in personal hygiene care products, the breathable membrane is an upgraded product of ordinary water-proof membranes. Breathable membranes cannot be simply replaced with ordinary membranes. The rational design of the final product structure is crucial to the performance of the breathable membrane.
The ventilation principle of the breathable membrane:
The so-called breathable film is a kind of functional inorganic product that is uniformly mixed into the polyolefin raw material, so that the product has pores due to high stretching during the film formation process, so as to have the function of breathability and moisture transmission; the function of the breathable film In short: Waterproof, breathable (moisture), take the most commonly used PE as a carrier as an example.
The mechanism of action of the breathable membrane:
When the water vapor concentration on one side of the film is greater than the environment on the other side of the film, a humidity gradient pressure difference is formed. This provides the basic conditions for gas (vapor) convection. Due to the formation of convection, the humidity environment on both sides of the film tends to be relatively balanced.
The breathable membrane is used as a water-proof membrane, which has a barrier effect on liquids. Because of the many passages in the membrane, the tortuous channel formed by it has a large "L/D" value, which can be understood as a capillary. Therefore, under the same liquid (such as water) and the same pressure, as long as the height of the liquid column of the capillary is less than the length of the capillary, the liquid will not leak out.
Therefore, the water resistance of the film directly depends on the pore size and channel length of the breathable film. This performance can usually be measured by water pressure resistance (ΔP). When the water pressure exceeds the water pressure resistance value that the microporous membrane can withstand, water will leak out. For the breathable film used in personal hygiene care products, the principle of improving the breathability of the film must be followed on the premise of ensuring safety (ΔP value).
(2) PE film + soft non-woven fabric:
Non-woven fabric (English name: English name: Non Woven Fabric or Nonwoven cloth), also known as non-woven fabric, is composed of directional or random fibers. It is a new generation of environmentally friendly materials. It is moisture-proof, breathable, flexible, light, and non-combustible , Easy to decompose, non-toxic, non-irritating, rich in color, low price, recyclable and other characteristics.
PE film + soft non-woven fabric, the surface layer can directly contact the baby's skin, accept and transmit liquid, soft to the touch, and does not irritate the baby's skin.
(3) Soft base film + hot air non-woven composite film:
The cotton soft base film is a combination of a breathable film and a thin cotton soft non-woven fabric. The purpose is to reduce the discomfort caused by the friction between the breathable membrane and the baby's skin and to absorb part of the sweat.
The hot air non-woven bottom film is a combination of air-permeable film and heated air non-woven fabric. Hot-air non-woven fabric belongs to a kind of hot-air bonding (hot-rolled, hot-air) non-woven fabrics. Hot-air non-woven fabrics are used to penetrate the fiber web by hot air on the drying equipment after the fiber is carded, so that it can be heated. Bonded non-woven fabric. Generally, products made by hot-air bonding have the characteristics of being fluffy, soft, good elasticity, and strong warmth retention, but their strength is low and they are easy to deform. With the development of the market, hot air adhesive products are widely used in the manufacture of disposable products with their unique style, such as baby diapers, adult incontinence pads, fabrics for feminine hygiene products, napkins, bath towels, disposable tablecloths, etc.
Main raw material of hot air non-woven fabric: ES fiber is the most ideal thermal bonding fiber, which is mainly used for non-woven fabric thermal bonding processing. When the carded fiber web is thermally bonded by hot-rolling or hot-air penetration, the low-melting-point components form a fusion bond at the intersection of the fibers. After cooling, the fibers at the non-intersections remain in their original state. It is a form of "point bonding" rather than "zone bonding", so the product has the characteristics of bulkiness, flexibility, high strength, oil absorption, blood absorption, etc. In recent years, the rapid development of thermal bonding method application depends entirely on these new synthetic fiber materials. The ES fiber and the PP fiber are mixed and then subjected to thermal bonding or needle punching treatment, so that the ES fibers are cross-linked and bonded. This method has the advantage that no adhesive and backing cloth are required. This feature can reduce the amount of hot melt adhesive in the process of processing diapers.
From this comparison, it can be seen that the soft base film + hot air non-woven composite film is a more skin-friendly material. Therefore, in recent years, diapers made of PE film have been gradually replaced by diapers made of non-woven fabrics.
The demand for diapers in the international market has been growing steadily, while the penetration rate of China’s baby diapers market is increasing rapidly, basically maintaining a growth rate of over 8%. Developed countries such as Europe, America and Japan still have room for growth. The new generation of young parents are generally born in the 80s and 90s, and their acceptance of baby diapers is higher. Young parents are more dependent on diapers, and the market penetration rate is expected to further increase with the iteration of the population.
The current international population aging problem is serious, and it has entered an aging society in a full sense. At present, there are as many as 37.5 million elderly people over the age of 65 in China who need long-term care. Together with the paralyzed and other incontinent patients under 65, it is conservatively estimated that there are about 40 million elderly people in China who need adult diapers. The current market penetration rate of adult diapers in China is only about 3%. Calculated by the global market penetration rate of 12%, the future market size of adult diapers in China will reach 10 billion yuan.
Due to the huge demand in the diaper market itself, and the rise of the Chinese market, many diaper manufacturers have spawned. The most important raw material for making diapers is non-woven fabrics, and the most important equipment is a diaper. Suntech has developed and manufactured smart diapers based on the standard of "precise engineering and intelligent manufacturing" and 50 years of technical precipitation and design experience, which has pushed the production of diapers to a new level and opened up a comfortable life for children and the elderly.