{
  "patent_number": "US 3489148",
  "country": "US",
  "title": "How Disposable Diapers Keep Skin Dry Using Porous Plastic Sheets",
  "original_title": "Topsheet for disposable diapers",
  "summary": "A 1970 patent by Procter and Gamble describing a specialized plastic top layer for diapers that allows liquid to pass through while keeping the baby's skin feeling dry.",
  "what_it_does": "This patent describes a hydrophobic, porous plastic film used as the inner layer of a disposable diaper. The material is designed with specific hole patterns that allow urine to quickly pass through into an absorbent core. Because the material is hydrophobic, or water-repelling, it prevents the liquid from flowing back to the surface, effectively separating the moisture from the baby's skin. This mechanism was a fundamental shift from using cloth or non-porous materials that would trap wetness against the skin.",
  "what_it_does_not_cover": [
    "Does not cover the absorbent core material itself, only the top layer in contact with the skin.",
    "Does not cover non-plastic or fabric-based top layers that rely on absorption rather than fluid transport through holes.",
    "Does not cover diapers that do not use a hydrophobic material to prevent liquid back-flow."
  ],
  "filed": "1966-12-20",
  "granted": "1970-01-13",
  "expires": "1987-01-13",
  "status": "expired",
  "holder": "Procter and Gamble Co",
  "holder_url": "https://patentbrief.org/company/procter-and-gamble-co",
  "inventors": [
    {
      "name": "Robert C Duncan",
      "url": "https://patentbrief.org/inventor/robert-c-duncan"
    },
    {
      "name": "Dale A Gellert",
      "url": "https://patentbrief.org/inventor/dale-a-gellert"
    }
  ],
  "times_cited": 133,
  "tags": [
    "consumer_electronics",
    "mechanical",
    "materials"
  ],
  "abstract": null,
  "url": "https://patentbrief.org/patent/us/3489148/disposable-diaper-topsheet",
  "markdown_url": "https://patentbrief.org/patent/us/3489148/disposable-diaper-topsheet/md",
  "google_patents_url": "https://patents.google.com/patent/US3489148",
  "relatedPatents": [
    {
      "patentNumber": "3585356",
      "countryCode": "US",
      "title": "How the Modern Waterbed Works",
      "url": "https://patentbrief.org/patent/us/3585356/waterbed-liquid-support"
    },
    {
      "patentNumber": "3220960",
      "countryCode": "US",
      "title": "How Soft Contact Lenses Were Invented Using Hydrogels",
      "url": "https://patentbrief.org/patent/us/3220960/soft-contact-lens-hydrogel"
    },
    {
      "patentNumber": "3953566",
      "countryCode": "US",
      "title": "Making Strong, Porous PTFE: The Gore-Tex Process",
      "url": "https://patentbrief.org/patent/us/3953566/gore-tex-expanded-ptfe"
    },
    {
      "patentNumber": "2982547",
      "countryCode": "US",
      "title": "How the First Modern Water Slide Was Designed",
      "url": "https://patentbrief.org/patent/us/2982547/slip-n-slide-carrier"
    },
    {
      "patentNumber": "3142599",
      "countryCode": "US",
      "title": "How Bubble Wrap Is Manufactured",
      "url": "https://patentbrief.org/patent/us/3142599/bubble-wrap-cushioning"
    }
  ]
}