US4244910A
Expired / Lapsed
US
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Method for injection molding of polyolefin containing inorganic filler
Assignee: Mitsubishi Chemical Corp
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Filing: 1979-09-25
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Granted: 1981-01-13
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Expires: 1999-09-25
Abstract
Abstract A method for molding a resin composition comprising a polyolefin and an inorganic filler to form a thin molded article, which comprises shooting said resin composition into a mold at such a high speed that its flow rate at the gate portion of the mold is at least 100 meters per second, thereby reducing the occurrence of short shots and the occurrence of mold flashing and making possible molding within a shorter period of time.
Inventors
- 👤 Hiroshi Yui
- 👤 Yoshihiro Sobajima
- 👤 Ryoichi Ichikawa
- 👤 Shigekazu Ema
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:28
CPC Classifications
B; B29; B29C; B29C70/00; B29C70/58; B29C45/00; B29C45/0013; B29K; B29K2709/00
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
100 words
A method for molding a polyolefin containing an inorganic filler to form articles having a thin wall thickness, which comprises kneading a composition comprising 30 to 95% by weight of a polyolefin and 5 to 70% by weight of an inorganic filler, and injection-molding the kneaded composition by shooting it into a cavity having a shape which will give a molded article the main portion of which has a thickness of about 0.2 to 1.0 mm at such a high speed that its flow rate at the gate portion of a mold is at least about 100 meters per second.
Claim 2
Independent Claim
100 words
A method for molding a polyolefin containing an inorganic filler to form articles having a thin wall thickness, which comprises kneading a composition comprising 30 to 95% by weight of a polyolefin and 5 to 70% by weight of an inorganic filler, and injection-molding the kneaded composition by shooting it into a cavity having a shape which will give a molded article the main portion of which has a thickness of about 0.2 to 1.0 mm at such a high speed that its flow rate at the gate portion of a mold is at least about 100 meters per second.
Claim 3
Dependent Claim
55 words
The method of claim 1, wherein said inorganic filler is at least one member selected from the group consisting of calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, calcium silicate, wollastonite, talc, clay, alumina, silica, iron oxide, mica, glass fibers, glass beads, hollow silica, hollow glass spheres, aluminum hydroxide, magnesium hydroxide and basic magnesium carbonate.
Claim 4
Dependent Claim
15 words
The method of claim 1, wherein said inorganic filler is talc, calcium carbonate or both.
Claim 5
Dependent Claim
20 words
The method of claim 1, wherein said inorganic filler has an average particle diameter of about 0.01 to 200 microns.
Claim 6
Dependent Claim
35 words
The method of claim 1, wherein said polyolefin is at least one member selected from the group consisting of homopolymers of alpha-olefins, copolymers of alpha-olefins with each other and copolymers of alpha-olefins with vinyl monomers.
Claim 7
Dependent Claim
24 words
The method of claim 1, wherein said polyolefin is a propylene-ethylene block copolymer having an ethylene content of about 2 to 15% by weight.
Claim 8
Dependent Claim
25 words
The method of claim 1, wherein the flow rate of said kneaded composition at the gate portion is at least about 400 meters per second.
Claim 9
Dependent Claim
19 words
The method of claim 1, wherein said resin is injected at a rate of at least about 100 ml/sec.
Claim 10
Dependent Claim
22 words
The method of claim 1, wherein said injection-molding is conducted at an injection pressure of at least about 800 kg/cm 2 .
Claim 11
Dependent Claim
17 words
The method of claim 1, wherein said injection molding is conducted at about 180° to 300° C.
Claim 12
Dependent Claim
21 words
The method of claim 1, wherein said kneaded composition has a melt flow rate of at least about 4 g/10 minutes.
Claim 13
Dependent Claim
18 words
The method of claim 1, wherein said kneaded composition is injected at a rate of about 500 ml/sec.
Claim 14
Dependent Claim
17 words
The method of claim 1, wherein said injection pressure is at least about 1,300 kg/cm 2 .
Claim 15
Dependent Claim
20 words
The method of claim 1, wherein said resin composition contains not more than about 20% by weight of another resin.
Claim 16
Dependent Claim
12 words
The method of claim 1, wherein upon kneading said composition is pelletized.
Claim 17
Dependent Claim
18 words
The method of claim 1, wherein the amount of said filler is about 15 to 60% by weight.
References Cited (Backward Citations)
US4067847A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |