Binder for powder metallurgy, mixed powder for powder metallurgy, and sintered body

{
  "publication_number": "US10240032B2",
  "country": "US",
  "kind": "B2",
  "title": "Binder for powder metallurgy, mixed powder for powder metallurgy, and sintered body",
  "abstract": "The present invention provides a binder which has excellent effect on suppression of segregation or dust emission, while exhibiting excellent fluidity both at ordinary temperatures and at high temperatures. The present invention is a binder which is blended for use in a mixed powder for powder metallurgy, said mixed powder containing an iron-based powder and an auxiliary starting material powder. This binder is characterized by being composed of one or more polymers that are selected from among butene polymers having a melting point of from 50° C. to 85° C. (inclusive) and a heated melt fluidity at 190° C. of from 2.0 g/10 minutes to 3.6 g/10 minutes (inclusive) and methacrylic acid polymers having a weight average molecular weight of 1,000,000 or less.",
  "claims": [
    "1. A binder, comprising: a butene polymer having a melting point of 50 to 85° C. and a melt fluidity at 190° C. of 2.0 to 3.6 g/10 min, and optionally a methacrylic acid polymer having a weight-average molecular weight of 1,000,000 or less.",
    "2. The binder of claim 1, comprising the methacrylic acid polymer.",
    "3. The binder of claim 2, comprising the methacrylic acid polymer in an amount of at least 5 mass %.",
    "4. The binder of claim 1, wherein the butene polymer is a copolymer of butene and a lower alkylene.",
    "5. The binder of claim 4, wherein the butene polymer is a butene-propylene copolymer or a butene-ethylene copolymer.",
    "6. A mixed powder, comprising: an iron-based powder; an auxiliary material powder; and the binder of claim 1.",
    "7. The mixed powder of claim 6, wherein a content of the binder is 0.01 to 0.5 mass % relative to a total of 100 mass % of the iron-based powder and the auxiliary material powder.",
    "8. The mixed powder of claim 6, wherein at least some of the iron-based powder and at least some of the auxiliary material powder are covered with the binder.",
    "9. A sintered body, produced by a method comprising: pressing and sintering the mixed powder of claim 6."
  ],
  "description_excerpt": "The present invention relates to a binder for powder metallurgy, which is blended for use in a mixed powder of a principal material powder and an auxiliary material powder, and a mixed powder for powder metallurgy, and a sintered body.\n\nIn a powder metallurgy process for manufacturing a product such as a sintered body using a principal material powder such as an iron-based powder, the principal material powder is mixed with an auxiliary material powder such as a graphite powder in order to improve physical properties, including a strength property and a processing property, of the sintered body, and the mixed powder is formed into a green compact by pressing. The green compact is sintered at a temperature equal to or lower than the melting point of the principal material powder to produce the sintered body.\n\nIt is generally pointed out that problems exist in a method of manufacturing such a sintered body. For example, it is known that when the formed green compact is extracted from a die, a friction coefficient between the green compact and a die surface may be increased, which causes die galling, i.e., scratches on the surface of the die, or damage to the die. A lubricant (for example, as in PTL 1) or the like therefore may be mixedly added into a mixed powder including a principal material powder and an auxiliary material powder in order to improve lubricating ability.\n\nFor example, the graphite, which is generally used as the auxiliary material powder, has a lower specific gravity and a smaller grain size than the iron-based powder as the principal material powder.",
  "cpc": [
    "C22C 38/00",
    "B22F 1/00",
    "B22F 1/0059",
    "B22F 1/10",
    "B22F 3/12",
    "C08L 23/20",
    "C08L 33/02",
    "C22C 33/02"
  ],
  "ipc": [
    "B22F 1/00",
    "B22F 1/10",
    "B22F 3/12",
    "C08L 23/20",
    "C08L 33/02",
    "C22C 38/00"
  ],
  "assignees": [
    "Kobe Steel Ltd"
  ],
  "inventors": [
    "Yoshihiro Ito",
    "Eiichiro Yoshikawa",
    "Nobuaki Akagi",
    "Mitsuhiro Sato"
  ],
  "filing_date": "2014-02-17",
  "publication_date": "2019-03-26",
  "grant_date": "2019-03-26",
  "priority_date": "2013-03-04",
  "application_number": "US-201414762725-A",
  "family_id": "51491078",
  "cited_by_count": 2,
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}