Baby Wipes

Background

Baby wipes are disposable cloths used to cleanse the sensitive skin of infants. These cloths are made from non-woven fabrics similar to those used in dryer sheets and are saturated with a solution of gentle cleansing ingredients. Baby wipes are typically sold in plastic tubs that keep the cloths moist and allow for easy dispensing.

History

The technology to create disposable non-woven towelettes was developed in the late 1970s, and the first baby wipe products appeared on the market soon after. Originally, due to the expense of the specialized equipment required to produce these products, major brands like Kimberly-Clark's Huggies and Proctor & Gamble's Pampers dominated the market. As the technology matured and became more affordable, smaller brands began to appear. By the 1990s, many large supermarket chains had their own private label brand of wipes made by contract manufacturers. These private label brands entice consumers with their lower prices and increase profits for the supermarkets.

Baby wipes are sold in the diaper section of supermarkets and generally run from three to five dollars for a 64-count tub. They are important to retailers because they help off-set the small profit margins that diaper sales generate. They are merchandised near diapers in the hope that consumers will purchase wipes along with their other infant care products. Wipes are available in different sizes and styles, and a typical store may carry between 10 and 20 different stock keeping units. Total supermarket sales of these pre-moistened towelettes jumped 5% from $251.4 million in 1996 to $263.9 million in 2000.

Design

Baby wipes are designed to be durable enough for heavy duty cleaning tasks, yet still be disposable. The fabric used for the cloths is chosen on the basis of durability, cost, and absorbency. This fabric is then saturated with a cleansing solution designed to be mild yet effective. Packaging is also an important design component and several patents have been granted for containers made specifically for pre-moistened towelettes. These packages are designed to easily dispense single sheets while keeping the towelettes moist until ready for use. Thermo-formed plastic tubs are most commonly used to package wipes in different amounts ranging from a few dozen to several hundred.

Marketers are continually designing new styles, sizes, and fornulations of baby wipes. Large-pack refills and attractive graphic labels are some of the recent innovations in the category. One private-label manufacturer uses Jim Henson's Muppet Babies to differentiate its product from competitors. Some products even have character outlines imprinted on the actual wipe. In Canada, premium quality wipes are marketed as having the advantages of being thicker, more absorbent, greater stretchability, hypo-allergenic, alcohol-free, pH-balanced, and/or unscented. Another factor that has impacted baby wipe design is the trend toward natural products. Marketers routinely add a variety of natural ingredients, such as aloe vera and oatmeal, to increase the consumer appeal of their products.

An example of a typical box of baby wipes.

Raw Materials

Non-woven fabric

The material used in baby wipes is a non-woven fabric similar to the type used in diapers and dryer sheets. Traditional fabrics are made by weaving together fibers of silk, cotton, polyester, wool, and similar materials to form an interlocking matrix of loops. Non-woven fabrics, on the other hand, are made by a process that presses a single sheet of material from a mass of separate fibers. Fibers, such as cotton and rayon, are used in this process, as well as plastic resins like polyester, polyethylene, and polypropylene.

Cleansing ingredients

Water is the main ingredient and serves as a carrier and diluent for the other ingredients. Baby wipes also contain mild detergents mixed with moisturizing agents, fragrance, and preservatives. The detergents most commonly used are known as amphoteric surfactants, similar to those found in baby shampoos. Sodium diamphoacetate and coco phosphatidyl PG-dimonium chloride are primary surfactants used in wipes. These chemicals don't strip the skin of natural oils and also decrease skin irritation potential. Mildness is a prime consideration given that the wipe solution may be in contact with delicate skin around the anus and genitals.

Humectants such as propylene glycol and glycerine are added to prevent premature drying of the solution and contribute to skin moisturization. In addition, some formulas incorporate oils such as mineral oil, lanolin, or silicones that help to soften skin. Thickeners, such as cellulose derivatives like hydroxymethyl cellulose, control the viscosity of the finished product and keep it the right consistency.

Other ingredients include preservatives, such as methyl and propyl paraben, to ensure the solution does not support microbial growth. Fragrance is usually added to increase consumer appeal and to help over-come body odors, but fragrance-free products are also offered. Featured ingredients may also be added to increase consumer appeal. These include natural ingredients that are known to be kind to the skin such as aloe vera or oatmeal extract.

Packaging components

Packaging used in baby wipes must keep the cloths free from contamination, yet allow for easy dispensing. The package must also prevent the towelettes from drying out. Thermo-molded plastic tubs are the packaging choice for most manufacturers. One common design features a hinged lid that allows easy access to the towelettes. These tubs are produced on injection molding equipment by pumping molten polyethylene plastic into a two part mold. Pressure is applied to the mold externally until the plastic cools. When the mold is opened, the plastic tub is ejected and stored until ready for filling.

The Manufacturing Process

Non-woven preparation

There are two primary methods of assembling non-woven fabrics: the wet laid process and the dry laid process.

• 1 One dry laid process is the "meltblown" method, which is used to make non-woven fabrics from plastic resins. In this method, plastic pellets are melted and then extruded, or forced through tiny holes, by air pressure. As the stream of fibers cools, it condenses to form a sheet. Hot metal rollers are used to flatten the fibers and bond them together.
• 2 A wet laid process is typically used for softer cloths, like diaper wipes, that use cotton blends. In this wet process, the fibers are made into liquid slurries with water and other chemicals. The resultant paste is pressed into flat sheets by rollers and then dried to form long rolls of fabric. These rolls are then further processed and slit into narrow widths and then perforated or cut into individual sheets. The finished cloths are classified by their dry weight that is at least 1.4 oz/in2 (40 g/m2). Absorbency of the wipes is also an important requirement (quality wipes can absorb between 200% and 600% of their weight in solution).

Formula preparation

• 3 The ingredients used in the wipe solution are prepared in large batch tanks. Depending on the formula requirements, the tank is charged with the first ingredient which is usually water. The tank may be heated during manufacturing to facilitate blending of powders that must be dissolved or other solids that must be melted. The other the ingredients are added sequentially and mixed until homogenous.

Non-woven treatment

• 4 Onced prepared, the non-woven cloth is fed from storage rolls onto coating machinery, where the cleansing solution is applied. Several methods can be employed in this process. The cleansing solution can be added by running the fabric through a trough of the solution, or sheets of fabric may be sprayed with the formula from a series of nozzles.
• 5 Alternatively, individual towelettes may be packaged in sealed foil pouches. In this process, sheets of laminated foil are fed into automated equipment which folds them into a small pouch and heat seals three sides to form an open envelope. Simultaneously, another conveyor line feeds the non-woven cloths into the pouch. A liquid feed mechanism, including conduits extending through the stuffing bars, injects moisturizing liquid into the towelette packet simultaneously with the stuffing of the towelette material.
• 6 Immediately following this operation, another heat sealer closes the pouch tightly.

Packaging operations

• 7 The finished cloths are automatically folded, stacked, and transferred to their final package. In one patented method employed by Rockline Inc. of Sheboygan, Wisconsin, the towelettes are folded and stacked so that they can easily be removed one at a time and then the stack is placed in an inner plastic pack. This inner pack is subsequently inserted into an outer tub with a hinged cover.

Quality Control

Each component used in baby wipes must pass a series of quality check points during the manufacturing process. The plastic packaging must be free from mold defects that could cause leakage or improper closure. The non-woven fabric must be uniformly formed and must meet specific tear-strength requirements. Furthermore, prior to manufacture, the cleansing solution must be thoroughly tested. Development chemists evaluate the product to ensure that it is shelf stable and will not undergo any undesirable chemical reactions. They must also test the formula to ensure that it satisfies the requirements for mildness. The most reliable method used to test mildness is known as the Human Repeat Insult Patch Test (HRIPT). In this test an ingredient, or series of ingredients, is applied to human volunteers (usually on the inside of the forearm). The area is then occluded with a patch material and the spot is evaluated by dermatologists or clinicians after a specified time. Any redness or irritation is assigned numerical value and the scores of all the panelists are averaged. A low average score, such as 0 or 1, indicates that the product is essentially non-irritating.

Before ingredients are added to the batch tank, they are assayed to ensure they conform to all relevant specifications. During manufacture, each ingredient is check weighed before it is added to the batch. Then final batch is tested again for basic specifications such as pH, viscosity, and microbial content.

The Future

From a marketing perspective, baby wipes are continually evolving. Supermarkets are planning to boost their declining margins on baby food and national-brand diapers by efficiently promoting private-label baby wipes sales. The market trend is leaning toward larger, more economical size. For example, Huggies recently introduced a 160-count refill package. Smaller travel size packages are also available from some manufacturers. From a technical perspective, as chemists develop new and improved surfactants, future versions of baby wipes will contain milder and more effective cleansing ingredients. Trends in fragrance and featured ingredients will also impact future formulations.