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Generation after generation, baby diapers have advanced to bring even more features and benefits to families. From cost and absorbency to product convenience, explore seven key areas of improvement—many supported by adhesives—that have led to new baby care products being used by millions of parents every day.

Disposable diapers have been around a long time. Today’s absorbent hygiene industry professionals might be the third or even fourth generation to wear them. Their children could actually be the fifth. But the products we use now have come a long way from those used by our mothers and grandmothers.

As early as the 1930s, industrial researchers in Europe and North America were exploring ways to create a mass-produced, disposable diaper. Since then, continual innovation and breakthroughs have allowed each generation of hygiene products to offer expanded benefits to families and their babies. Where would today’s families be without:

  • Low unit cost
  • High absorbency
  • Leak-through protection
  • Elastic strands
  • Easy closure and removal
  • Thinner designs
  • Wetness indicators

These features that parents rely on daily have evolved over time. In fact, those earliest adopters might not even recognise the diapers we use today. Adhesives, including hot melts, have played a role in enabling many of those enhancements.

From Luxury Good to Family Staple

By the early 2000s, it was estimated that more than nine of every 10 diaper changes in the developed world today were disposables.[1] But it certainly hasn’t always been that way.

For years, families with babies relied on basic cotton diapers. As a product, they were inexpensive, easily laundered, and readily available. In the 1950s, disposable options were found in 80% of American households with infants. Even so, they accounted for less than 1% of diaper changes. Why? Largely because of the expense.[2]

At that time, disposables in the United States cost more—sometimes much more—than 10¢ a diaper. That translates to about $1.15 each in 2023 terms. Consumers considered them a luxury item, reserved for specific situations. Cloth was more economical for general use. But that would change.

Procter & Gamble first tested Pampers® in 1961 in Peoria, Illinois. Whilst consumers rated the product highly, the cost (4-5 times that of cloth diapers) resulted in disappointing sales. The company concluded that the product would not truly succeed until the cost could be reduced by 40 percent or more.[3]

Over the next few years, the production process was simplified and line speeds accelerated. Adhesives were one component in the faster, more efficient process. By 1964, P&G tested the new version in Indianapolis, Indiana. At less than 6¢ per diaper, the product quickly sold out, leaving customers wanting more.

[1] ‘Seven Decades of Disposable Diapers’, Davis Dyer, The Winthrop group, on behalf of EDANA.

[2] Ibid.

[3] Ibid.

Improved Absorbency and SAP

The earliest disposable alternatives had been made with a variety of absorbent materials, from paper to textile fibers. For example, some included stacks of 15 to 25 sheets of tissue paper. They could hold an estimated 100ml of fluid, which meant that they needed to be changed after every use.

Shortly after the original tissue-core diaper was released, Paulistrom introduced the first fluff core, made of cellulose wadding. It was designed to be put into reusable panties to help with fluid absorption and distribution, as well as improved performance.[1] For years, fluff dominated the disposable core, supported by adhesives for construction and stabilization.

Then, in the 1980s, absorbency made another big leap when Unicharm introduced superabsorbent baby diapers in Japan. Compared to an all-fluff core, superabsorbent polymer (SAP) could hold greater volumes of fluid, even under pressure. But SAP alone tends to absorb and wick fluid slowly, so fluff had to stay to provide absorption speed and wicking … and to improve comfort. Core wraps kept the SAP/fluff matrix together. Adhesives helped to ensure the core functioned as intended and to minimize the discomfort that swelling clumps of SAP could cause.

The next generation of parents came to appreciate the thinner diapers enabled by SAP, as well as the higher absorbency. At the time, 30% SAP/70% fluff was common. Over time, manufacturers explored higher and higher percentages of SAP, with adhesives taking on a variety of roles.

In cores with up to 50% SAP, the fluff fibers entangled to create a pad that keeps the SAP in place and supports core integrity. To improve the core’s integrity even more, a core wrap can be used. This wrap surrounds the SAP/fluff and is sealed with a core adhesive.

When the ratio of SAP to fluff increases, manufacturers find themselves facing additional challenges. At 70% SAP, a core wrap and a core adhesive are both needed to prevent the loss of SAP powder. Moreover, a core at 70% SAP may immediately fail if a core integrity adhesive is not used.[2]

[1] Ibid.

[2] Internal studies using Bostik’s Conditioned Core Integrity Test.

Leak-through Protection

One weakness of cotton diapers and their early competitors was the fact that the insult could leak through. In the 1950s, separate rubber pants could be placed over cloth diapers, but they could be uncomfortable, especially in warmer climates.

To combat wet sensation with their disposables, P&G introduced two new substrates into their existing product. The first was a hydrophobic top sheet made of rayon to keep moisture in the absorbent tissue layer. The other was a large plastic back sheet to help contain leakage.[1] Construction adhesives could be used to hold these diverse components in place.

[1] ‘Seven Decades of Disposable Diapers’, Davis Dyer, The Winthrop group, on behalf of EDANA.

Elastics to Support Fit and Protection

The addition of elastics in baby diapers was a case of incremental innovation. The early rubber pants of the 1950s may not have been truly elasticized, but they had a stretchy waistband to provide a snug fit and prevent leakage. For the same reason, some cloth diapers at the time offered rubberized bands embedded in the waist.

Elasticised leg cuffs were introduced in the 1980s, as part of the move toward more ‘anatomical’ shapes.[1] The elastics allowed the diaper to better conform to a baby’s shape, for enhanced comfort and leak protection. Specific adhesives were used that enabled elastics to stretch and contract whilst holding them firmly in place.

Over time, the use of elastics has continued to expand. Today, they can be found in legs, cuffs, belly, and waist. They are also a key component of pant-style diapers.

[1] Ibid

Easy Closure and Removal

For decades, the safety pin (invented in 1849) was the standard closure for baby diapers. But other types of closures began to come into vogue during the 1980s and were definitely appreciated by many parents of that generation. Available options included resealable tabs, Velcro, and other mechanical closures.

Another simplification for the user arrived with the launch of a pant-style diaper. The elastic bands around the waist allow them to be pulled on easily, even by children of potty-training age. In fact, that was the target demographic when Kimberly-Clark first introduced Huggies Pull-Ups® in 1989.

Today the pant-style chassis is used to various degrees in markets around the world. Some regions continue to use them primarily for potty training, whilst in others they are popular even at much earlier ages. For easy removal and reduced mess, styles are available that can be torn open at the sides after use.

Newer, Thinner Designs: Zero-fluff, Compound, and Channel Cores

In recent years, the baby diaper industry has enjoyed a synergy with the adult incontinence market in a drive toward ever thinner cores. One goal is to enable articles that are much closer in thickness and style to underwear. The result has been the introduction of new core designs.

Fluff-free cores use no cellulose fibers to hold the SAP powder in place. Even incorporating new polymers that have better wicking and absorption speed, a core adhesive is needed to avoid cracking. And not all core adhesives will do. In fluff-free cores, the adhesive must allow adequate wicking and expansion as the SAP absorbs the insult.

In China, manufacturers created an entirely new configuration called the compound core, or 复合芯体 in Chinese. Instead of fluff, the SAP is sprinkled on layers of a high-loft nonwoven, commonly PET (polyethylene terephthalate). This structure ensured the core would not crack, but it presented difficulties regarding adequate line speed and SAP loss during production.

To address the issue, some diaper manufacturers choose to use a pre-compound core that is produced off-line. These rolls of cores can be shipped and attached later, during diaper production. Specific adhesives can be used to fix the SAP in place.

Another design that has grown in use is the channel core, which features longitudinal zones free of absorbent material. These areas are formed by bonding the upper and lower core wrap materials with adhesive. Some producers include fluff in their channel cores. Others do not. The number and shape of channels may also vary by manufacturer and brand.

Wetness Indicators: Boosting Convenience and Skin Health

Think way back to your mother’s or even grandmother’s time. With the earliest diapers, they knew a change was needed when the wetness began to seep through. After back sheets were added, mothers waited for the smell (or the baby’s cries), or they put their fingers in the back of the diaper to feel for the insult.

Then in 1978 Kimberly-Clark introduced the visual wetness indicator in their Kleenex® Super Dry line. Printed designs on the diaper’s exterior would fade, blur, or disappear as the product became wet. This competitive advantage allowed for more timely changes. No reaching inside, less chance of a leak, and a lower chance of skin irritation for baby.

Today, visual wetness indicators are a far more common feature, accomplished variously through dyes or hot melt options. Some parents are even looking for enhanced functionality, such as faster reaction times or a more obvious color change.

In 2000, another kind of indicator was released. In their Pull-Ups® training pants, Huggies® introduced ‘Learning Designs®’, featuring haptic wetness indicators. These involved a raised texture on the inner liner that would become smooth or disappear when wet. This offered the child a tactile clue to feel and, potentially, lead to a connection between wetness and needing a change.

Booster Pads with Stay-in-Place Adhesives

Absorbent pads are nothing new. Some of the earliest disposable options were designed to be tucked into underwear or rubber liners. One weakness, however, was their ability to shift out of position, especially when put into regular apparel.

In more recent times, parents can use booster pads to add an extra layer of absorbency. Designed to slip into diapers, today’s booster pads also come with an added feature: the pad attachment adhesive. This sticky strip holds the pad in place firmly and comfortably.

Future Innovations Toward Sustainability

Of course, many of today’s absorbent hygiene products have one weakness. By their very nature of being disposable, they are generally considered not to be as sustainable as cloth diapers. But here, too, innovation is at work.

Companies are exploring the use of new materials in substrates, ranging from hemp and bamboo to bio-sourced polymers.

Research also continues in formulating even more sustainable and bio-based adhesives for diapers. For example, Bostik scientists are working to improve bond strength, flexibility, and skin-friendliness whilst minimizing environmental impact.

Choosing the Right Adhesives for Your Baby Care Products

Looking to bring the next big diaper innovation to the market that benefits babies and their families? We strongly recommend involving Bostik’s absorbent hygiene adhesive experts in the early stages of development. With our expertise, we can help you quickly identify the nonwoven adhesive solutions that best meet your design needs, for products the next generation of parents and babies will love.

Contact an Expert!

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All information contained herein is believed to be accurate as of the date of publication, is provided “as-is” and is subject to change without notice. To review our full U.S. Legal Disclaimer, visit: https://bostik.com/us/en_US/privacy-policy/legal-disclaimer

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