{
  "spore": "profile",
  "id": "fr-4",
  "spore_version": "0.2",
  "family": "glass-and-composites",
  "name": "FR-4 glass-fibre epoxy laminate",
  "abbreviation": "FR-4",
  "role": "rigid circuit-board substrate, woven glass cloth bonded with epoxy resin",
  "category": "electronics",
  "type": "circuit-board-laminates",
  "summary": "FR-4 is a NEMA grade of rigid laminate made of woven glass cloth bonded with epoxy resin, self-extinguishing and used as the substrate of almost all printed circuit boards. This profile reads the Isola 370HR FR-4 product page, a standard-loss, thermally robust epoxy laminate with a glass transition of 180 °C by DSC, a decomposition temperature of 340 °C at 5 % weight loss, and a dielectric constant of 4.17 at 1 GHz. No space flight data for FR-4 was read in this run.\n",
  "best_for": "Standard printed circuit boards: 180 °C Tg and 60 min T260 for multilayer boards, as printed for Isola 370HR",
  "weakest_at": "Loss at high frequency and expansion above Tg: a Z-axis CTE of 230 ppm/°C above Tg, and a dissipation factor of 0.0210 at 2 GHz",
  "identity": {
    "formula": "Woven E-glass cloth impregnated with an epoxy resin binder; laminate of glass fibre and epoxy, flame-retardant grade",
    "cas": "",
    "designations": [],
    "source": "wikipedia-fr4",
    "where": "Lead section (FR-4 is a NEMA-designated composite of woven glass cloth bonded with an epoxy resin binder)"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "electronics-and-chips"
    ]
  },
  "properties": [
    {
      "benchmark": "tg",
      "label": "Glass transition temperature (DSC), Isola 370HR",
      "value": 180,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "method_as_printed": "DSC, IPC-TM-650 2.4.25C"
      },
      "method": "Typical value printed on the Isola product page, Typical Values table",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Glass Transition Temperature (Tg) by DSC row",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "decomposition_temperature",
      "label": "Decomposition temperature (TGA, 5 % weight loss), Isola 370HR",
      "value": 340,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "method_as_printed": "TGA at 5 % weight loss, IPC-TM-650 2.4.24.6"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Decomposition Temperature (Td) row",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "time_to_delamination",
      "label": "Time to delaminate by TMA at 260 °C (T260), Isola 370HR, copper removed",
      "value": 60,
      "bound": "exact",
      "unit": "min",
      "scope": "material",
      "conditions": {
        "temperature": "260 °C",
        "copper": "removed",
        "method_as_printed": "TMA, IPC-TM-650 2.4.24.1"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Time to Delaminate by TMA, sub-row A. T260",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "time_to_delamination",
      "label": "Time to delaminate by TMA at 288 °C (T288), Isola 370HR, copper removed",
      "value": 30,
      "bound": "exact",
      "unit": "min",
      "scope": "material",
      "conditions": {
        "temperature": "288 °C",
        "copper": "removed",
        "method_as_printed": "TMA, IPC-TM-650 2.4.24.1"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Time to Delaminate by TMA, sub-row B. T288",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Z-axis CTE, pre-Tg, Isola 370HR",
      "value": 45,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "range": "below Tg",
        "method_as_printed": "IPC-TM-650 2.4.24C"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Z-Axis CTE, sub-row A. Pre-Tg",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Z-axis CTE, post-Tg, Isola 370HR",
      "value": 230,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "range": "above Tg",
        "method_as_printed": "IPC-TM-650 2.4.24C"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Z-Axis CTE, sub-row B. Post-Tg",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Z-axis total expansion, 50 to 260 °C, Isola 370HR",
      "value": 2.8,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "range": "50 to 260 °C",
        "method_as_printed": "IPC-TM-650 2.4.24C"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Z-Axis CTE, sub-row C. 50 to 260°C (Total Expansion)",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "X-axis CTE, pre-Tg, Isola 370HR",
      "value": 13,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "range": "below Tg",
        "axis": "X",
        "method_as_printed": "IPC-TM-650 2.4.24C"
      },
      "method": "Typical value printed on the Isola product page, printed as 13/14 for X/Y",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, X/Y-Axis CTE row, first figure",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Y-axis CTE, pre-Tg, Isola 370HR",
      "value": 14,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "range": "below Tg",
        "axis": "Y",
        "method_as_printed": "IPC-TM-650 2.4.24C"
      },
      "method": "Typical value printed on the Isola product page, printed as 13/14 for X/Y",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, X/Y-Axis CTE row, second figure",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, Isola 370HR",
      "value": 0.4,
      "bound": "exact",
      "unit": "W/m·K",
      "scope": "material",
      "conditions": {
        "method_as_printed": "ASTM E1952"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Thermal Conductivity row",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant (permittivity) at 1 GHz, Isola 370HR",
      "value": 4.17,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 GHz",
        "method_as_printed": "IPC-TM-650 2.5.5.9"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Dk Permittivity, sub-row B. @ 1 GHz",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant (permittivity) at 2 GHz, Isola 370HR",
      "value": 4.04,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "2 GHz",
        "method_as_printed": "Bereskin stripline"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Dk Permittivity, sub-row C. @ 2 GHz",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "dissipation_factor",
      "label": "Dissipation factor (loss tangent) at 1 GHz, Isola 370HR",
      "value": 0.0161,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 GHz",
        "method_as_printed": "IPC-TM-650 2.5.5.9"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Df Loss Tangent, sub-row B. @ 1 GHz",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "dissipation_factor",
      "label": "Dissipation factor (loss tangent) at 2 GHz, Isola 370HR",
      "value": 0.021,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "2 GHz",
        "method_as_printed": "Bereskin stripline"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Df Loss Tangent, sub-row C. @ 2 GHz",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "peel_strength",
      "label": "Peel strength, standard profile copper, at 125 °C, Isola 370HR",
      "value": 1.25,
      "bound": "exact",
      "unit": "N/mm",
      "scope": "material",
      "conditions": {
        "temperature": "125 °C",
        "copper": "standard profile",
        "method_as_printed": "IPC-TM-650 2.4.8.3"
      },
      "method": "Typical value printed on the Isola product page; 7.0 lb/inch printed alongside",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Peel Strength, sub-row B. at 125ºC",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Flexural strength, length direction, Isola 370HR",
      "value": 620,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "direction": "length",
        "method_as_printed": "IPC-TM-650 2.4.4B"
      },
      "method": "Typical value printed on the Isola product page; 90.0 kpsi printed alongside",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Flexural Strength, sub-row A. Length direction",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "moisture_absorption",
      "label": "Moisture absorption, Isola 370HR",
      "value": 0.15,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "method_as_printed": "IPC-TM-650 2.6.2.1A"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Moisture Absorption row",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "electric_strength",
      "label": "Electric strength, laminate and laminated prepreg, Isola 370HR",
      "value": 54,
      "bound": "exact",
      "unit": "kV/mm",
      "scope": "material",
      "conditions": {
        "method_as_printed": "IPC-TM-650 2.5.6.2A"
      },
      "method": "Typical value printed on the Isola product page; 1350 V/mil printed alongside",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Electric Strength row",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "volume_resistivity",
      "label": "Volume resistivity after moisture resistance, Isola 370HR",
      "value": 300000000,
      "bound": "exact",
      "unit": "MΩ-cm",
      "scope": "material",
      "conditions": {
        "state": "after moisture resistance",
        "method_as_printed": "IPC-TM-650 2.5.17.1"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Volume Resistivity, sub-row A. After moisture resistance",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "relative_thermal_index",
      "label": "Relative thermal index, Isola 370HR",
      "value": 130,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "method_as_printed": "UL 796"
      },
      "method": "Typical value printed on the Isola product page",
      "status": "ground",
      "source": "isola-370hr-page",
      "where": "Typical Values table, Relative Thermal Index (RTI) row",
      "source_detail": {
        "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
        "id": "Isola Group product page, 370HR laminate and prepreg",
        "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "tg",
      "label": "Glass transition temperature (DSC), Shengyi S1000-2M",
      "value": 180,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "method_as_printed": "IPC-TM-650 2.4.25D, DSC"
      },
      "method": "Typical value printed on the Shengyi datasheet",
      "status": "ground",
      "source": "shengyi-s1000-2m",
      "where": "General Properties table, Tg row, DSC",
      "source_detail": {
        "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03), with prepreg and line-up tables",
        "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf",
        "year": 2018,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "tg",
      "label": "Glass transition temperature (DMA), Shengyi S1000-2M",
      "value": 185,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "method_as_printed": "IPC-TM-650 2.4.24.2, DMA"
      },
      "method": "Typical value printed on the Shengyi datasheet",
      "status": "ground",
      "source": "shengyi-s1000-2m",
      "where": "General Properties table, Tg row, DMA",
      "source_detail": {
        "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03), with prepreg and line-up tables",
        "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf",
        "year": 2018,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "decomposition_temperature",
      "label": "Decomposition temperature (TGA, 5 % weight loss), Shengyi S1000-2M",
      "value": 355,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "method_as_printed": "IPC-TM-650 2.4.24.6, TGA at 5 % weight loss"
      },
      "method": "Typical value printed on the Shengyi datasheet",
      "status": "ground",
      "source": "shengyi-s1000-2m",
      "where": "General Properties table, Td row",
      "source_detail": {
        "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03), with prepreg and line-up tables",
        "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf",
        "year": 2018,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Z-axis CTE, pre-Tg, Shengyi S1000-2M",
      "value": 41,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "range": "below Tg",
        "method_as_printed": "IPC-TM-650 2.4.24"
      },
      "method": "Typical value printed on the Shengyi datasheet",
      "status": "ground",
      "source": "shengyi-s1000-2m",
      "where": "General Properties table, CTE (Z-axis) before Tg row",
      "source_detail": {
        "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03), with prepreg and line-up tables",
        "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf",
        "year": 2018,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Z-axis CTE, post-Tg, Shengyi S1000-2M",
      "value": 208,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "range": "above Tg",
        "method_as_printed": "IPC-TM-650 2.4.24"
      },
      "method": "Typical value printed on the Shengyi datasheet",
      "status": "ground",
      "source": "shengyi-s1000-2m",
      "where": "General Properties table, CTE (Z-axis) after Tg row",
      "source_detail": {
        "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03), with prepreg and line-up tables",
        "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf",
        "year": 2018,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant (permittivity) at 1 GHz, Shengyi S1000-2M",
      "value": 4.6,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 GHz",
        "method_as_printed": "IPC-TM-650 2.5.5.9, C-24/23/50"
      },
      "method": "Typical value printed on the Shengyi datasheet",
      "status": "ground",
      "source": "shengyi-s1000-2m",
      "where": "General Properties table, Permittivity (1GHz) row",
      "source_detail": {
        "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03), with prepreg and line-up tables",
        "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf",
        "year": 2018,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "dissipation_factor",
      "label": "Dissipation factor (loss tangent) at 1 GHz, Shengyi S1000-2M",
      "value": 0.018,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 GHz",
        "method_as_printed": "IPC-TM-650 2.5.5.9, C-24/23/50"
      },
      "method": "Typical value printed on the Shengyi datasheet",
      "status": "ground",
      "source": "shengyi-s1000-2m",
      "where": "General Properties table, Loss Tangent (1GHz) row",
      "source_detail": {
        "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03), with prepreg and line-up tables",
        "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf",
        "year": 2018,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    },
    {
      "benchmark": "resin_content",
      "label": "Prepreg resin content by glass style, Shengyi S1000-2MB",
      "value": 44,
      "value_high": 77,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "basis": "nominal prepreg resin content, range across glass styles 106 to 7628"
      },
      "method": "Range across the glass styles in the Shengyi prepreg table, minimum and maximum as printed",
      "status": "ground",
      "source": "shengyi-s1000-2m",
      "where": "PREPREG PARAMETERS table, Resin content column",
      "source_detail": {
        "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03), with prepreg and line-up tables",
        "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf",
        "year": 2018,
        "kind": "datasheet",
        "license": "manufacturer datasheet, linked not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Humidity with a DC voltage across adjacent vias (CAF test)",
      "headline": "Copper salt filaments grow along the epoxy-glass interface and can short adjacent vias or planes.",
      "effect": "In the NPL CAF test, laminate was held at 85 °C and 85 % RH for up to 1000 hours with a DC voltage across vias. Vias closer together fail sooner, anodic vias fail faster than cathodic ones, and higher voltage shortens time to failure. CAF-resistant DICY-free resins reduce the risk, and identically specified laminates from different suppliers performed differently.",
      "rating": "severe",
      "conditions": {
        "temperature": "85 °C",
        "humidity": "85 % RH",
        "duration": "up to 1000 h"
      },
      "source": "npl-caf-matc155",
      "where": "Abstract (test method), and section 6, Conclusions"
    },
    {
      "environment": "Moisture before and during use",
      "headline": "Moisture starts the leakage path, and BT resin has the best CAF record of the materials compared.",
      "effect": "Turbini describes CAF as a copper hydroxy chloride salt that grows from anode to cathode along the epoxy-glass interface, and as enhanced by high humidity, high voltage gradient, multiple thermal cycles and higher lead-free processing temperatures. In the comparison Turbini cites, bismaleimide triazine (BT) was the most CAF-resistant material, attributed to its low moisture absorption.",
      "rating": "moderate",
      "conditions": {},
      "source": "turbini-caf-history",
      "where": "Introduction paragraphs, and the comparison of FR-4, G-10, polyimide, triazine and MC-2 substrates"
    },
    {
      "environment": "Reflow and lead-free soldering",
      "headline": "A 250 °C reflow peak is potentially harmful to CAF performance.",
      "effect": "NPL lists peak reflow temperatures of 250 °C as potentially harmful to the CAF performance of a laminate. Its conclusions also say the board house's own processing gives laminates different CAF performance, so the laminate must be tested as built.",
      "rating": "moderate",
      "conditions": {
        "peak": "250 °C"
      },
      "source": "npl-caf-matc155",
      "where": "Section 6, Conclusions, Reflow conditions and Manufacturing"
    },
    {
      "environment": "Thermal stress at soldering temperatures",
      "headline": "Shengyi S1000-2M withstands 288 °C solder dip for over 100 s and gives T260 above 60 min.",
      "effect": "Shengyi prints by TMA (IPC-TM-650 2.4.24.1) a T260 above 60 min, a T288 of 30 min and a T300 of 15 min, and a solder-dip thermal stress at 288 °C of over 100 s. These show delamination time falls quickly above 260 °C, which matches the Isola 370HR figures recorded above.",
      "rating": "low",
      "conditions": {
        "temperature": "260 to 300 °C"
      },
      "source": "shengyi-s1000-2m",
      "where": "General Properties table, rows T260, T288, T300 and Thermal Stress"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem record for tetrabromobisphenol A (CID 6618), formula C15H12Br4O2 and molar mass 543.9 g/mol, aggregated GHS: H350 may cause cancer, H400 and H410 very toxic to aquatic life, and H351 suspected of causing cancer in 21.2 percent of notifications. This describes the additive, not the cured laminate. No safety data sheet for an FR-4 laminate was read.",
        "ghs": [
          "H350",
          "H351",
          "H400",
          "H410"
        ],
        "source": "pubchem-tbbpa",
        "where": "Safety and Hazards, GHS Classification (aggregated)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Expansion through thickness above Tg",
        "trigger": "Heating a board above its glass transition, where the Z-axis CTE rises from 45 to 230 ppm/°C",
        "consequence": "Plated-through-hole and copper stress as the board expands; the page prints a 2.8 % total Z-axis expansion from 50 to 260 °C",
        "severity": "moderate",
        "source": "isola-370hr-page",
        "where": "Typical Values table, Z-Axis CTE rows A to C"
      },
      {
        "mode": "CAF short between vias or planes",
        "trigger": "Humidity with a DC voltage across adjacent vias, with anodic vias failing first",
        "consequence": "A copper-salt filament grows along the epoxy-glass interface and causes an electrical short; the NPL test ran at 85 °C and 85 % RH for up to 1000 hours",
        "severity": "critical",
        "source": "npl-caf-matc155",
        "where": "Abstract, and section 6, Conclusions"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Shengyi prepreg keeps 3 months below 23 °C and under 50 % RH, or 6 months below 5 °C, in damp-proof wrap. It should normalise at room temperature for at least 4 h before use, since moisture uptake weakens bonding strength.",
        "source": "shengyi-s1000-2m",
        "where": "Prepreg, Storage Condition"
      }
    ],
    "mitigations": [
      {
        "text": "Specify a CAF-resistant laminate, such as a DICY-free resin, but test the board as the board house builds it, because processing changes CAF results (NPL).",
        "source": "npl-caf-matc155",
        "where": "Section 6, Conclusions"
      },
      {
        "text": "Stagger vias at 45 degrees to the weave, since NPL found this resists CAF better than vias aligned with warp or weft at the same gap.",
        "source": "npl-caf-matc155",
        "where": "Section 6, Conclusions, Alignment to reinforcement"
      },
      {
        "text": "Limit reflow peaks; NPL calls 250 °C potentially harmful to CAF performance.",
        "source": "npl-caf-matc155",
        "where": "Section 6, Conclusions, Reflow conditions"
      }
    ]
  },
  "uses": [
    {
      "application": "electronics-and-chips",
      "device": "Printed circuit board substrate",
      "example": "Isola 370HR, a standard-loss, thermally robust epoxy laminate with a 180 °C Tg and a 1 GHz dielectric constant of 4.17, as printed on the product page.",
      "source": "isola-370hr-page",
      "where": "Product page summary and Typical Values table"
    },
    {
      "application": "electronics-and-chips",
      "device": "Computers and communication equipment",
      "example": "Shengyi S1000-2M, a high-Tg FR-4 with anti-CAF capability, lists computer, communication and automotive electronics as applications.",
      "source": "shengyi-s1000-2m",
      "where": "Features and Applications box, first page of the datasheet"
    },
    {
      "application": "electronics-and-chips",
      "device": "Printed circuit boards in general",
      "example": "FR-4 glass epoxy is described as the most common insulating substrate for printed circuit boards.",
      "source": "wiki-pcb",
      "where": "Printed circuit board article, substrate paragraph"
    }
  ],
  "supply": [
    {
      "subject": "Copper foil",
      "abundance": "Mine production in 2025e, thousand metric tons of copper content: Chile 5,300, Congo (Kinshasa) 3,200, Peru 2,700, China 1,800, United States 1,000. China leads refinery output at 14,000. The US net import reliance was 57 percent of apparent consumption in 2025e. Electrical and electronic products took 23 percent of copper use, per the Copper Development Association.",
      "producers": [],
      "critical_lists": [],
      "recycling": "Not sourced.",
      "substitutes": [],
      "source": "usgs-mcs2026-copper",
      "where": "World Mine and Refinery Production and Reserves table, Salient Statistics, Domestic Production and Use paragraph"
    },
    {
      "subject": "Laminate producers",
      "abundance": "No production volume or country share for FR-4 laminate was printed on the pages read.",
      "producers": [
        {
          "country": "Isola Group"
        },
        {
          "country": "Shengyi Technology Co., Ltd."
        },
        {
          "country": "Panasonic"
        }
      ],
      "critical_lists": [],
      "recycling": "Not sourced.",
      "substitutes": [
        "Bismaleimide triazine (BT) resin was the most CAF-resistant material in the comparison Turbini cites, attributed to its low moisture absorption."
      ],
      "source": "shengyi-s1000-2m",
      "where": "Datasheet footer and copyright line; Isola 370HR product page"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page (typical values)",
      "type": "datasheet",
      "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/"
    },
    {
      "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03)",
      "type": "datasheet",
      "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf"
    },
    {
      "title": "Panasonic MEGTRON 6 R-5775, product page (general properties)",
      "type": "datasheet",
      "url": "https://industrial.panasonic.com/ww/products/pt/megtron/megtron6"
    },
    {
      "title": "NPL Report MATC(A)155, Susceptibility of glass-reinforced epoxy laminates to conductive anodic filamentation",
      "type": "report",
      "url": "https://eprintspublications.npl.co.uk/3017/1/MATC155.pdf"
    },
    {
      "title": "Turbini, Conductive Anodic Filament (CAF) Formation: An Historic Perspective",
      "type": "paper",
      "url": "https://www.electronics.org/system/files/technical_resource/E17&S02-3.pdf"
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026, Copper",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf"
    },
    {
      "title": "PubChem, Tetrabromobisphenol A (CID 6618), GHS classification",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/6618"
    }
  ],
  "gaps": [
    "Isola 370HR PDF datasheet could not be read: WebFetch returned only compressed PDF streams, so its values were taken from the product page instead.",
    "Isola FR408HR product page returned HTTP 404, so no second FR-4 type from Isola was read.",
    "Ventec VT-4 product page redirected and returned HTTP 404, so no Ventec values were read.",
    "The Panasonic MEGTRON 6 page was read, but it is a low-loss grade rather than a standard FR-4, and no Panasonic FR-4 grade was read. Its Dk and Df are at 13 GHz and are not compared with the 1 GHz values here.",
    "everythingrf 370HR page returned HTTP 403.",
    "Dielectric values differ between sources and test methods, so Dk and Df are recorded only at the frequencies and methods printed on the Isola page.",
    "No IPC-4101 grade limits were read in this run. IPC-4101/126 is named only on the Shengyi datasheet, and the IPC standard is named on the Wikipedia IPC article.",
    "Glass cloth (E-glass) and epoxy resin supply shares, producers and abundance were not found in the pages read, so the supply section covers copper foil and laminate makers only.",
    "No NASA source for FR-4 outgassing was read: the NTRS PDF tried in this run returned HTTP 404.",
    "The resin_content property uses a short snake_case name because it is not in the canonical list.",
    "The Shengyi S1000-2M datasheet line-up page is dated July 2018 and marks its Dk and Df values as not guaranteed. Its values appear in the story text only, not as properties, and the current Shengyi datasheet was not read.",
    "Consumer devices such as phones and laptops are not named in any source read here, so the uses list names computers and communication equipment only.",
    "No space flight, outgassing, atomic oxygen, or radiation data for FR-4 was read in this run.",
    "Peel strength values at 125 °C and after thermal stress come from the Isola page layout; the row pairing was read from extracted text and is the page's best reading.",
    "Dielectric breakdown, arc resistance, CTI and flammability (UL 94 V-0) are printed on the Isola page but are not recorded because they are ratings or lower-bound values, not single numbers."
  ],
  "story": {
    "why": "FR-4 is a woven glass cloth bonded with epoxy resin, flame retardant and self-extinguishing. It is the default substrate for printed circuit boards. The Isola 370HR grade prints a glass transition of 180 °C, a decomposition temperature of 340 °C, and a dielectric constant of 4.17 at 1 GHz.",
    "uses": [
      {
        "where": "Computers and communication equipment",
        "line": "Shengyi lists computer, communication and automotive electronics as applications for the S1000-2M grade."
      },
      {
        "where": "Printed circuit boards",
        "line": "Wikipedia describes FR-4 glass epoxy as the most common insulating substrate for printed circuit boards."
      }
    ],
    "can_do": [
      {
        "label": "Survive thermal stress",
        "line": "The 370HR page prints 60 minutes to delaminate by TMA at 260 °C with copper removed, and 30 minutes at 288 °C.",
        "benchmark": "time_to_delamination",
        "scope": "material",
        "value": "60 min T260"
      },
      {
        "label": "Hold a stable board",
        "line": "Below Tg the X and Y CTE are printed as 13 and 14 ppm/°C, close to copper, so plated holes stay under less stress.",
        "benchmark": "cte",
        "scope": "material",
        "value": "13 ppm/°C X-axis CTE"
      },
      {
        "label": "Stay insulating",
        "line": "After moisture resistance the volume resistivity is printed in MΩ-cm, and the electric strength as 54 kV/mm.",
        "benchmark": "electric_strength",
        "scope": "material",
        "value": "54 kV/mm"
      }
    ],
    "compare": "Isola 370HR and Shengyi S1000-2M are both high-Tg FR-4 grades. The 370HR page prints a glass transition of 180 °C by DSC, a decomposition temperature of 340 °C and a Z-axis CTE of 45 ppm/°C below Tg. Shengyi prints 180 °C by DSC and 185 °C by DMA, a decomposition temperature of 355 °C and a Z-axis CTE of 41 ppm/°C below Tg, with anti-CAF capability. At 1 GHz Shengyi prints a permittivity of 4.6 and a loss tangent of 0.018, against 4.17 and 0.0161 for the 370HR, so the 370HR is the lower-loss grade at 1 GHz. Panasonic MEGTRON 6 R-5775 is a different class, a low-loss, high-speed laminate rather than a standard FR-4 grade. Its values are read from the Panasonic product page but are not compared here, because they are taken at a different frequency and for a different product.",
    "compare_rows": [
      {
        "label": "Tg",
        "benchmark": "tg",
        "scope": "material"
      },
      {
        "label": "Dielectric constant",
        "benchmark": "dielectric_constant",
        "scope": "material"
      },
      {
        "label": "Dissipation factor",
        "benchmark": "dissipation_factor",
        "scope": "material"
      }
    ],
    "handling": [
      "Check the grade and the test frequency before comparing dielectric values, since Dk and Df vary with frequency and method.",
      "Use the supplier datasheet for each grade, since the values here are typical values from one product page."
    ],
    "good_for": [
      "Standard printed circuit boards: 180 °C Tg and 340 °C Td on the Isola 370HR page.",
      "Multilayer boards that need a high T260: 60 minutes at 260 °C with copper removed."
    ],
    "watch_out": [
      "Dissipation factor rises with frequency, from 0.0161 at 1 GHz to 0.0210 at 2 GHz on the same page.",
      "Z-axis expansion above Tg is 230 ppm/°C, so boards should stay below Tg in service.",
      "No space or outgassing data for FR-4 was read, so it is not recorded for orbit use.",
      "Humid conditions with a DC voltage can grow CAF shorts between vias. NPL found closer vias and anodic vias fail sooner, and higher voltage shortens time to failure."
    ],
    "verdict": "FR-4 is the standard circuit-board substrate. The Isola 370HR grade read here has a Tg of 180 °C, a Td of 340 °C, a dielectric constant of 4.17 at 1 GHz and a dissipation factor of 0.0161 at 1 GHz. Its high-frequency loss and Z-axis expansion above Tg are the limits, and no space-flight data was read.",
    "recipe": {
      "line": "FR-4 is woven glass cloth impregnated with an epoxy resin binder, then hot-pressed into laminate. The cloth type, the resin and the cloth-to-resin ratio set the laminate's type designation (Wikipedia, PCB article). The resin is a brominated epoxy, using tetrabromobisphenol A as the flame retardant (Wikipedia, TBBPA article). Shengyi cures its prepreg with a hot-pressing cycle of more than 60 min at 185 to 195 °C. The laminate and prepreg standard is IPC-4101, and Shengyi cites specification sheet IPC-4101/126.",
      "parts": [
        {
          "name": "E-glass woven cloth",
          "symbol": "glass",
          "role": "Woven reinforcement. The glass style sets the resin content and cured thickness.",
          "share_note": "Resin content by glass style is printed in the Shengyi prepreg table; the range is recorded as the resin_content property",
          "source": "shengyi-s1000-2m"
        },
        {
          "name": "Epoxy resin binder",
          "symbol": "epoxy",
          "role": "Binds the glass cloth into a rigid laminate. The resin system sets the glass transition and the thermal stress limits.",
          "share_note": "Share not printed on the pages read",
          "source": "wiki-fr4"
        },
        {
          "name": "Tetrabromobisphenol A",
          "symbol": "TBBPA",
          "role": "Brominated flame retardant built into the epoxy. A lower grade of TBBPA is used to prepare epoxy resins for printed circuit boards (Wikipedia). PubChem gives its formula and molar mass.",
          "share_note": "Share not printed on the pages read; atoms C15H12Br4O2",
          "source": "wiki-tbbpa"
        },
        {
          "name": "Copper foil",
          "symbol": "Cu",
          "role": "Conductor layer on the surface of the board.",
          "share_note": "Foil thickness is printed in the Shengyi purchasing table, laminated to the board surface",
          "source": "shengyi-s1000-2m"
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "No safety data sheet for an FR-4 laminate was read. The hazard data below is for TBBPA, the flame-retardant additive in the resin.",
        "points": [
          {
            "label": "Additive",
            "line": "PubChem aggregated GHS for TBBPA: H350 may cause cancer, H351 in 21.2 percent of notifications, and H400 and H410 for aquatic toxicity."
          },
          {
            "label": "Handling",
            "line": "Shengyi prepreg keeps 3 months below 23 °C and under 50 % RH, and must be normalised for at least 4 h before use."
          }
        ],
        "level": 1,
        "verdict": "Additive hazards only"
      },
      {
        "title": "If it fails",
        "lead": "The failure route in the source is thermal expansion through the board thickness above Tg.",
        "points": [
          {
            "label": "Z-axis expansion",
            "line": "The Isola 370HR page prints a Z-axis CTE of 45 ppm/°C below Tg and 230 ppm/°C above Tg, with 2.8 % total expansion from 50 to 260 °C."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-19",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 28,
    "unreachable": 5,
    "caveats": 6,
    "note": "Deepen pass on 2026-10-19 by an AI assistant. Kept the 20 existing properties and 2 existing sources. Added 8 properties for the second FR-4 grade, Shengyi S1000-2M (Tg by DSC and DMA, Td, Z-axis CTE before and after Tg, Dk and Df at 1 GHz, and prepreg resin content). Added recipe, supply, corrosion (ageing), uses, hazards, failure risks, handling, mitigations and story sections, and 9 sources: Shengyi S1000-2M datasheet (read as a PDF via curl and pdftotext), Panasonic MEGTRON 6 product page (second laminate maker, read through WebFetch), NPL MATC(A)155 and Turbini CAF papers (text read via pdftotext), USGS Copper MCS 2026 (PDF), PubChem CID 6618 (TBBPA GHS), and Wikipedia PCB, TBBPA and IPC articles. Unreachable in this run: Isola 370HR PDF (binary only), Isola FR408HR page (404), Ventec VT-4 page (404), everythingrf page (403), NASA NTRS PDF (404). Caveats: the numeric properties still come from one product page; Dk and Df differ by source and frequency; the Shengyi and Panasonic values appear in the story text, not as properties; the TBBPA hazard describes the additive, not the cured laminate."
  },
  "sources": {
    "isola-370hr-page": {
      "title": "Isola 370HR Industry Leading Epoxy Laminate and Prepreg, product page, Typical Values table",
      "id": "Isola Group product page, 370HR laminate and prepreg",
      "url": "https://www.isola-group.com/pcb-laminates-prepreg/370hr-laminate-prepreg/",
      "year": 2026,
      "kind": "datasheet",
      "license": "manufacturer web page, linked not reproduced"
    },
    "wikipedia-fr4": {
      "title": "FR-4, Wikipedia",
      "id": "Wikipedia article FR-4, lead section and Properties table",
      "url": "https://en.wikipedia.org/wiki/FR-4",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA, linked not reproduced"
    },
    "shengyi-s1000-2m": {
      "title": "Shengyi S1000-2M and S1000-2MB technical datasheet (CN-TDS-1901-03), with prepreg and line-up tables",
      "url": "https://www.eurotronics.be/wp-content/uploads/2021/11/Shengyi-S1000-2M-S1000-2MB-datasheet.pdf",
      "year": 2018,
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      "license": "manufacturer datasheet, linked not reproduced"
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      "title": "Panasonic MEGTRON 6 R-5775, product page, general properties table",
      "url": "https://industrial.panasonic.com/ww/products/pt/megtron/megtron6",
      "kind": "web",
      "license": "manufacturer web page, linked not reproduced"
    },
    "npl-caf-matc155": {
      "title": "NPL Report MATC(A)155, Susceptibility of Glass-Reinforced Epoxy Laminates to Conductive Anodic Filamentation",
      "url": "https://eprintspublications.npl.co.uk/3017/1/MATC155.pdf",
      "year": 2004,
      "kind": "report",
      "license": "Crown copyright, extracts reproduced with source given; linked not reproduced"
    },
    "turbini-caf-history": {
      "title": "Conductive Anodic Filament (CAF) Formation: An Historic Perspective, Turbini, ECWC 10 and APEX 2005",
      "url": "https://www.electronics.org/system/files/technical_resource/E17&S02-3.pdf",
      "year": 2005,
      "kind": "paper",
      "license": "conference paper, linked not reproduced"
    },
    "usgs-mcs2026-copper": {
      "title": "USGS Mineral Commodity Summaries 2026, Copper",
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      "year": 2026,
      "kind": "report",
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    },
    "pubchem-tbbpa": {
      "title": "PubChem, Tetrabromobisphenol A (CID 6618), Safety and Hazards",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/6618",
      "year": 2026,
      "kind": "database",
      "license": "public database, linked not reproduced"
    },
    "wiki-tbbpa": {
      "title": "Tetrabromobisphenol A, Wikipedia, Production and use",
      "url": "https://en.wikipedia.org/wiki/Tetrabromobisphenol_A",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA, linked not reproduced"
    },
    "wiki-pcb": {
      "title": "Printed circuit board, Wikipedia, substrate and laminate type",
      "url": "https://en.wikipedia.org/wiki/Printed_circuit_board",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA, linked not reproduced"
    },
    "wiki-ipc": {
      "title": "IPC (electronics), Wikipedia, standards list",
      "url": "https://en.wikipedia.org/wiki/IPC_(electronics)",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA, linked not reproduced"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/fr-4/"
}