Engineering the disposable diaper

For the mothers of the baby boom, pediatrician Benjamin Spock’s child care handbook was a practical, confidence-boosting essential. Originally published in 1946 as The Common Sense Book of Baby and Child Care, Dr Spock’s baby book sold more than 500,000 copies in its first six months. By the time the second edition came out in 1957, with the simplified title Baby and Child Care, Dr Spock was selling a million copies a year. My mother, who was 24 when I arrived in 1960, still remembers the book’s reassuring tone.

‘You know more than you think you do’, the author told readers. ‘We know for a fact’, he wrote with medical authority, ‘that the natural loving care that kindly parents give to their children is a hundred times more valuable than their knowing how to pin a diaper on just right’.

Dr Spock went on to provide detailed instructions on the practical intricacies of parenthood, including diapers. Buy at least two dozen, he counseled, more if you aren’t washing them daily. Six dozen would cover all contingencies. With a diagram, he showed how to fold a diaper and explained how to position it on a boy versus a girl. ‘When you put in the pin’, he advised, ‘slip two fingers of the other hand between the baby and the diaper to prevent sticking him’. The book covered when to change the diapers and what to do with the dirties.

You want a covered pail partially filled with water to put used diapers in as soon as removed. If it contains soap or detergent, this helps in removing stains. Be sure the soap is well dissolved, to prevent lumps of soap from remaining in the diapers later. When you remove a soiled diaper, scrape the movement off into the toilet with a knife, or rinse it by holding it in the toilet while you flush it (hold tight).

You wash the diapers with mild soap or mild detergent in [the] washing machine or washtub (dissolve the soap well first), and rinse 2 or 3 or 4 times. The number of rinsings depends on how soon the water gets clear and on how delicate the baby’s skin is. If your baby’s skin isn’t sensitive, 2 rinsings may be enough.

On this subject, the 1957 edition contains two telling differences from the original. In 1946, Dr Spock recommended the knife method to those without flush toilets. And starting with the second edition, he advised new parents to buy an automatic washer and dryer if they could possibly afford them. ‘They save hours of work each week, and precious energy’, he wrote. ‘Energy’ in this case referred not to electricity or gas but to maternal stamina.

Disposable diapers did exist, but they accounted for a mere one percent of US diaper changes. They were expensive, specialty products and not that great. ‘The full-sized ones are rather bulky’, noted Dr Spock. ‘The small ones that fit into a waterproof cover do not absorb as much urine as a cloth diaper and do not retain a bowel movement as well’. Disposables were mostly used for travel, when washing diapers wasn’t an option.

But even as the second edition of Baby and Child Care was hitting bookstores and supermarket racks, change was afoot. After buying Charmin Paper Company in 1957, Procter & Gamble began looking for ideas for new paper products. 

Motivated by the less pleasant aspects of spending time with his new grandchild, the company’s director of exploratory development, Victor Mills, suggested disposable diapers. After analyzing existing products and conducting consumer research, P&G created a dedicated diaper research group.

The research this group conducted, like that of its successors and competitors, wasn’t glamorous. It didn’t advance basic science. It wasn’t even an obvious route to profit. (One percent of the market!) It was a high-stakes gamble that required solving difficult engineering problems. How that happened represents the kind of hidden progress that leads to everyday abundance.

P&G’s first design flopped. Tested in the extreme heat of a Dallas summer, the pleated absorbent pad with plastic pants made babies miserable and left them with heat rashes. Starting over, the group had a one piece diaper ready for testing in March 1959. With an improved rayon moisture barrier between the baby and the absorbent tissue wadding, the new diaper was softer and more comfortable. An initial test of 37,000 hand-assembled prototypes went well, with about two thirds of the parents deeming the disposables as good or better than cloth. The next step was mass production.

Designing one well-functioning disposable was hard enough. Turning out hundreds a minute was practically impossible. ‘I think it was the most complex production operation the company had ever faced’, an engineer recalled.

There was no standard equipment. We had to design the entire production line from the ground up. It seemed a simple task to take three sheets of material – plastic back sheet, absorbent wadding, and water repellent top sheet – fold them in a zigzag pattern and glue them together. But glue applicators dripped glue. The wadding generated dust. Together they formed sticky balls and smears which fouled the equipment. The machinery could run only a few minutes before having to be shut down and cleaned.

Eventually, the diaper team mastered the process. In December 1961, Pampers went on the market in Peoria, Illinois. Once again, the test failed.

This time mothers liked the diapers. But the price was way too high for a single use item: ten cents a diaper, equivalent to about one dollar today. By contrast, diaper delivery services, which served about five percent of the market, charged no more than five cents a diaper. Home laundry costs ran to one or two cents.

Lowering the price of a diaper required much larger volumes. Aiming at about six cents a diaper, P&G engineers spent several years developing what Harvard Business School’s Michael E. Porter described as ‘a highly sophisticated block-long, continuous-process machine that could assemble diapers at speeds of up to a remarkable 400 a minute’. After successfully testing Pampers at 5.5 cents each, P&G began a national rollout in 1966. By 1973, disposables accounted for 42 percent of the US diaper market.

A noteworthy success was in Puerto Rico, which Pampers entered in 1972. Although incomes were significantly lower than in the continental US, the island’s poverty actually favored disposables. Many families lacked easy access to washing machines, and line drying diapers was tough in the humid climate. ‘Puerto Rico became one of the most successful Pampers markets’, records Oscar Schisgall in Eyes on Tomorrow, a corporate history of P&G. Disposable diapers turned out to be a particular boon to poor families.

The success of Pampers drew competitors into the growing market. ‘Any diaper maker that carved out a modest market share against Procter & Gamble could expect sales to triple as a result of sheer market growth’, write business historians Thomas Heinrich and Bob Batchelor in Kotex, Kleenex, Huggies, a history of Kimberly-Clark. But there was a catch. The bulky diapers took up so much space on shelves that stores rarely stocked more than two brands, plus maybe a discounted private label. Second place meant profits, third place disaster.

Most entrants gave up within a few years. Scott Paper abandoned the market in 1971. International Paper exited in 1972. Union Carbide left in 1977. Johnson & Johnson held on until 1981. J&J was adept at marketing baby products but couldn’t get its machines to turn out diapers fast enough to keep prices competitive.

Kimberly-Clark was the exception. The company that had introduced the world to Kleenex tissues and Kotex feminine pads, both completely new concepts in the 1920s, created a disposable diaper called Kimbies. It featured tape fasteners and an unusual triangular fold. Buyers liked the tape fasteners, which Pampers soon copied, but complained that the weirdly folded diapers leaked. After a disastrous switch in the glue affixing the cover lining to the pad, Kimbies began losing shelf space to J&J. In 1975, the company decided the only way to survive in the diaper business was to start over with a better design.

The new diapers, introduced as Kleenex Huggies in December 1977, were elasticized along the edge of the crotch to prevent leaks. Manufacturing them was a complicated process requiring custom-designed machines. Heinrich and Batchelor write:

A tissue machine combined layers of absorbent padding into sheets of varying thickness to form the wings and the crotch section, which was 15 percent thicker than the edges. Once the sheet had been cut into individual hourglass shapes, the latter received an elastic band at the crotch section and were combined with the cover and backing sheet to form the diaper.

Huggies had tapes that could be refastened without tearing the plastic cover, an annoyance I remember from my days as a teenage babysitter. Like P&G’s premium Luvs, which included similar features, Huggies cost about 30 percent more than regular disposables. But consumers were willing to pay more for higher quality diapers.

‘At a time of rampant inflation, declining real wages, and economic uncertainty, consumers flocked from Johnson & Johnson’s moderately priced diapers to the Huggies and Luvs premium brands’, write Heinrich and Batchelor. As Huggies expanded nationally, J&J sales cratered.

The following decade saw fierce competition between the two remaining diaper giants, with Huggies eventually becoming the market leader. In the mid-1980s, P&G and Kimberly-Clark replaced paper wadding with superabsorbent polymers (SAPs) that trap water like particles in a net. As manufacturers learned how to work with these wonder materials, disposable diapers got thinner and better.

‘In the early eighties’, wrote Malcolm Gladwell in a 2001 New Yorker feature, ‘they were three times bulkier than they are now, thicker and substantially wider in the crotch. But in the mid-eighties Huggies and Procter & Gamble’s Pampers were reduced in bulk by fifty percent; in the mid-nineties they shrank by a third or so; in the next few years they may shrink still more’.

As diapers got slimmer, they took up less space in trucks and on shelves. Shipping costs dropped, allowing fewer factories farther apart. More shelf space permitted greater variety. ‘We cut the cost of trucking in half’, Ralph Drayer, P&G’s former logistics chief, told Gladwell. ‘We cut the cost of storage in half. We cut handling in half, and we cut the cost of the store shelf in half, which is probably the most expensive space in the whole chain’.

In 1987, Huggies got an unexpected boost from a cameo in the Coen Brothers farce Raising Arizona. It starred Nicolas Cage as a convenience store robber who marries Holly Hunter’s police photographer after she takes his mug shot. Needing diapers for the baby they’ve swiped from a family of quintuplets, Cage’s character hits a convenience store, grabbing a huge package of Huggies and waving a pistol (unloaded). ‘Wake up, son!’, he drawls to the young clerk, who looks up from perusing Juggs magazine. ‘I’ll be taking these Huggies and [shrug], uh whatever cash you got’. The filmmakers picked Huggies, Ethan Coen told a journalist, because ‘it sounded funnier than any other brand name’.

Meanwhile, Kimberly-Clark was secretly working on a product that would shock competitors: disposable training pants for toddlers. It wasn’t a new idea, but the execution was tricky, requiring enough side elasticity to allow little hands to pull up their britches without adult help. What Heinrich and Batchelor describe as ‘an innovative synthetic fabric’ was the key. Huggies Pull-Ups Training Pants debuted in 1989, completely blindsiding Procter & Gamble. ‘Huggies Pull-Ups in fact reigned unchallenged for the next three years, capturing 9 percent of the diaper market and generating more than $200 in annual sales for Kimberly-Clark,’ write Heinrich and Batchelor. In 1992, a smaller competitor, Drypers, finally introduced a rival product.

By this time, disposable diapers had become a nursery necessity, commanding some 95 percent of the diaper market in the United States, Canada, Japan, and most of Europe. (The UK and Netherlands lagged by about a decade.) It was time for a backlash.

In the late 1980s and early 1990s, US environmentalists proposed restrictions on disposable diapers. Florida, Pennsylvania, and Vermont considered outright bans, while bills elsewhere would have exempted only disposables whose materials were biodegradable. New Hampshire’s legislature considered a ten cent tax on every diaper. In California, a 1990 bill supported by the Sierra Club would have required a package label declaring that ‘single-use disposable diapers pose significant environmental problems and costs when disposed. The state of California recommends that you consider reusable diapers for your daily diaper needs’. New York legislators proposed a similarly reproachful label.

None of these laws passed. In part, they failed because their environmental claims were disputed. Research by William Rathje, a University of Arizona archaeologist who spent decades analyzing the contents of landfills, found that disposable diapers made up less than two percent of US trash.

Others pointed to the complexities of measuring environmental harms across the entire diaper lifecycle, which would include water needed for irrigating cotton fields and washing dirty diapers. There were ‘too many ambiguities’ to declare disposables an environmental no-no, said Allen Hershkowitz of the Natural Resources Defense Council, which remained neutral on the issue.

Nonsense, responded green critics. Hershkowitz wasn’t a reliable source, Fred Munson of Greenpeace told the Los Angeles Times. ‘He has a kid and uses disposables’, said Munson, ‘and I personally think he is trying to placate his conscience’.

It was a petty ad hominem, but it contained a truth. Punitive bans, warning labels, and diaper taxes were doomed not because of wonky arguments about landfill contents and lifecycle analysis but because normal people love disposable diapers. Few parents would willingly return to diaper pails and daily loads of diaper laundry. Threaten their Huggies and you’re likely to find yourself out of office.

‘As a mother’, wrote humorist Erma Bombeck in a 1990 syndicated column. ‘I’d rather do away with foam cups and have hot coffee poured into both my hands than do away with disposable diapers’.