What Is the Crinkly Stuff in Baby Toys? Crinkle Material Explained

ByA Little Bit Brilliant Team
Diagram of what is inside a crinkle toy: fabric on the outside, a sheet of crinkle film in the middle, fabric on the back

In the products and patents we checked, the crinkly stuff in baby toys is a thin sheet of plastic film sewn inside the toy’s fabric. Sewing suppliers sell it as “crinkle material” or “crinkle paper,” and a toy patent application says it is “often called crinkle paper or baby paper.” Sellers list the film as PET or polyamide, and a 1965 baby-toy patent used polyester film sold under the Mylar trademark.

Below: what crinkle material is made of, why it makes that sound, how to check a crinkle toy for safety, and how to wash one without ruining it. Every source we checked is listed at the end.

Diagram of what is inside a crinkle toy: fabric on the outside, a sheet of crinkle film in the middle, fabric on the back

What is crinkle material made of?

The sources we opened do not agree on one plastic. Here is what each one says:

Source What it says the crinkle layer is
US Patent 3,221,444 (1965), a baby “noise producing placater” “The polyester film sold under the trademark Mylar,” between 0.0005 and 0.005 inch thick, inside “washable fabric”
US Patent Application 2016/0158658, an infant sensory toy “Crinkle material, often called crinkle paper or baby paper”
US Patent 5,067,925, an infant’s toy “A plastic material having air pockets therein that cause a crackling sound when squeezed,” the kind used for packing cartons
Two crinkle film sellers on Amazon PET film (seller claim)
One crinkle film seller on Amazon Polyamide film (seller claim)

So crinkle material is a thin plastic film, and the plastic named depends on the source. We could not find a toy brand or industry group that says which plastic most baby toys use.

You will also find crinkle material outside of soft toys. A European patent for a baby mat notes that activity mats often include “crinkle material, mirrors or squeakers.”

What makes the crinkle sound in baby toys?

Physicist Eric Kramer, who recorded crumpled Mylar sheets, asked why candy and cereal packaging is so noisy in a lay-language paper for the Acoustical Society of America. His answer: “The answer seems to be the creases.” What he found:

  • Squeezing stores energy. “Small deformations put energy into the sheet,” and once enough is stored, the sheet “snaps through” to a new shape.
  • Each snap is one click. The sound is a string of “discrete pulses of sound with a typical duration less than 10 ms.”
  • Few creases, little sound. “If you can find a piece with few creases, then small deformations of the material should produce little or no noise.”
  • Thicker film clicks less, but louder. “Thicker sheets produced fewer clicks and were somewhat louder.”

Wrinkling the film first makes it louder. The 1965 patent says the sound “is accentuated after the Mylar film has been pre-wrinkled,” and one crinkle film seller tells sewists to crumple the sheet first for “a louder, more satisfying crinkle sound.”

Why do babies like crinkle toys?

We did not find a CDC or AAP page that explains why babies like crinkle sounds in particular. What they do describe is what babies are learning to do with sounds, hands and mouths in the first months:

Age What the CDC lists (Learn the Signs. Act Early.)
2 months “Reacts to loud sounds” · “Looks at a toy for several seconds” · “Opens hands briefly”
4 months “Holds a toy when you put it in his hand” · “Uses his arm to swing at toys” · “Brings hands to mouth” · “Turns head towards the sound of your voice”
6 months “Reaches to grab a toy she wants” · “Puts things in her mouth to explore them”

The American Academy of Pediatrics lists “textured toys that make sounds” among toys appropriate for 4- to 7-month-olds. In its play guide, it also suggests letting babies “bring safe objects to their mouth to explore and experience new textures.”

Is crinkle material safe for babies?

Crinkle film is meant to stay inside the toy. One supplier’s instructions say to “sew in between 2 layers of fabric,” and one crinkle film listing on Amazon carries the warning “CHOKING HAZARD — Small parts. Not for children under 3 yrs.” On a related note, the CPSC has asked parents to remove the peel-off plastic film that covers parts like mirrors on children’s products, because it “can pose a choking hazard to children.” It reported two cases where young children nearly choked on the protective film from the mirror of a baby jumper.

The rules that apply to the toy itself:

  • The small parts rule. Federal rule 16 CFR 1501 covers toys meant for children under 3, including “squeeze toys; teethers” and “stuffed, plush, and flocked animals.” Any part that fits entirely in the CPSC’s small parts test cylinder fails, and that cylinder “approximates the size of the fully expanded throat of a child under three years old.”
  • The US toy standard. ASTM F963-23 became the mandatory US toy standard on April 20, 2024. The CPSC’s chart of the standard lists sections for “Plastic Film,” “Stuffing Materials,” “Sound-Producing Toys,” and “Stuffed & Bean Bag-Type Toys.”
  • Chemical claims. Several crinkle film sellers say their film meets CPSIA and EN71. Those are the sellers’ own claims, and we could not verify them independently.

A quick crinkle toy check

  1. Squeeze every seam. AAP: “Make sure all the parts are on tight and seams and edges are secure.”
  2. Look for film poking out. CPSC: “Broken toys can develop sharp edges or create small parts. A toy that cannot be repaired should be thrown away immediately.”
  3. Do the toilet paper roll test on tags, rings and add-ons. AAP: make sure toys and parts “can’t fit into a toilet paper roll, to prevent choking (especially for children less than 3 years).”
  4. Keep it out of the crib. AAP: “Soft objects, loose bedding, or any objects that could increase the risk of entrapment, suffocation, or strangulation should be kept out of the crib.”
  5. Check for recalls. AAP: “Toys that are recalled should be removed right away.”
  6. When in doubt, put it away. Nemours KidsHealth: “If you have any doubt about a toy’s safety, don’t let your baby play with it.”

Can you wash crinkle toys?

It depends on the label, and labels differ:

If the label says What to do Source
Machine washable “Launder items (if possible) according to the manufacturer’s instructions.” “Use the warmest appropriate water setting and dry items completely.” CDC (child care guidance)
Surface clean only Do what the label says. One crinkle teether toy’s label says: “Surface clean only. Clean the teether before each use with a damp cloth. Air dry. Do not immerse in water.” Itzy Ritzy product page
It goes in baby’s mouth “Sanitize surfaces that come in contact with children’s mouths, such as infant feeding items and toys.” CDC (child care guidance)

Crinkle film sellers describe their material as “washer, dryer and even low iron safe” and “manufactured to be washed and dried with no issues.” When you shop, the AAP says a stuffed toy “should also be machine washable.”

For a schedule, the child care standard Caring for Our Children lists: washable cloth toys used by one child are cleaned weekly and machine washed and dried completely before another child uses them, and mouthed toys are cleaned before and after each use. That is a standard for child care programs, not a home rule. More in our guides on how often to wash baby toys, cleaning plush toys, and toys that go in the mouth.

What can I use for crinkle in a DIY baby toy?

On sewing forums (for example Quiltingboard and PatternReview), people say they use potato chip bags, cereal box liners, cellophane, or Mylar blankets. We could not find an official source that rules on food bags either way.

Purpose-made crinkle film is sold for this job. Its sellers say it is designed to be “washed, dried, and played with extensively,” and one supplier’s instructions say to “sew in between 2 layers of fabric.” The Amazon crinkle film listing quoted above carries a small parts warning for the loose sheet. Step-by-step instructions are in how to make a crinkle baby toy, and supply options are in where to buy crinkle material for baby toys.

FAQ

What is the crinkle material in baby toys called?

It is sold as crinkle material or crinkle paper. One toy patent application says it is also called baby paper. It is a thin plastic film, not paper.

What do they put in baby crinkle toys?

A sheet of thin plastic film sewn between fabric layers. Sellers list PET or polyamide film, and patents describe polyester (Mylar) film or bubble-style packing plastic.

What makes the crinkle sound in baby toys?

Most likely the creases. Research on crumpled sheets found that stored energy makes the sheet "snap through" to a new shape, and each click typically lasts less than 10 milliseconds. A 1965 toy patent says pre-wrinkling the film makes the sound stronger.

Is crinkle material safe for babies?

Crinkle film is meant to be sewn inside the fabric, and one listing for loose crinkle film warns "CHOKING HAZARD — Small parts. Not for children under 3 yrs." Nemours KidsHealth says to check toys "often for loose or broken parts," and the CPSC says "A toy that cannot be repaired should be thrown away immediately."

Can you put crinkle toys in the washing machine?

Only if the label says so. Some are machine washable, and some, like Itzy Ritzy's crinkle teether toy, say "Surface clean only."

Sources

This guide is general information for parents and caregivers. Always follow the toy’s own label and age range.

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