US3904342A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for manufacturing of tubular biaxially stretched film having improved thickness uniformity
Assignee: Resonac Holdings Corp
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Filing: 1973-05-03
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Granted: 1975-09-09
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Expires: 1993-05-03
Abstract
Abstract A tubular biaxially stretched film of synthetic resin having little unevenness of thickness is produced by a method with high molding stability whereby the film is uniformly heated, stretched and cooled while the surrounding atmosphere of the film in motion is kept as free from disturbance as possible and the film itself is prevented from vibrating. For the production of this film, there is used as apparatus which comprises in combination a preheater barrel of which the portion for introducing a tubular film of synthetic resin is so constructed as to permit passage of the film alone and preclude passage of gas, a stretching barrel having a larger diameter than the preheater barrel and serving the purpose of stretching the film, and a cooling jacket adapted to give abrupt cooling to the stretched film so as to improve the stretching and molding stability.
Inventors
- 👤 Wasuke Sato
- 👤 Osamu Uemura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:56
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/28
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
226 words
An improved apparatus for the manufacture of a tubular biaxially stretched film of synthetic resin, composed of an upper pair of nip rollers adapted to introduce a tube of film of synthetic resin, a lower pair of nip rollers rotated at a greater speed than said upper nip rollers, a heater unit disposed to intervene between said two pairs of nip rollers, a V-shaped stabilizer plate and a gas-introducing unit, the improvement comprising in combination (a) a preheater barrel consisting of (a'') a head portion adapted to permit passage of the tube of film and impede passage of gas and (a'''') the inner wall of which has a diameter greater than the diameter of the tube of film, gains stepwise in diameter downwardly and outer wall incorporates an indirect heater element and (b) a stretching barrel adjoining the lowermost end of said preheater barrel and formed of an inner wall which has a diameter greater than that of the stretched tube of film and an outer wall which incorporates an indirect heater element and (c) a cooling jacket disposed below half the height of and beyond said stretching barrel around the path of the stretched tube of film to effect abrupt cooling of the tube of film by intercepting the radiant heat emanating from the outer wall of the stretching barrel toward the tube of film.
Claim 2
Dependent Claim
226 words
An improved apparatus for the manufacture of a tubular biaxially stretched film of synthetic resin, composed of an upper pair of nip rollers adapted to introduce a tube of film of synthetic resin, a lower pair of nip rollers rotated at a greater speed than said upper nip rollers, a heater unit disposed to intervene between said two pairs of nip rollers, a V-shaped stabilizer plate and a gas-introducing unit, the improvement comprising in combination (a) a preheater barrel consisting of (a'') a head portion adapted to permit passage of the tube of film and impede passage of gas and (a'''') the inner wall of which has a diameter greater than the diameter of the tube of film, gains stepwise in diameter downwardly and outer wall incorporates an indirect heater element and (b) a stretching barrel adjoining the lowermost end of said preheater barrel and formed of an inner wall which has a diameter greater than that of the stretched tube of film and an outer wall which incorporates an indirect heater element and (c) a cooling jacket disposed below half the height of and beyond said stretching barrel around the path of the stretched tube of film to effect abrupt cooling of the tube of film by intercepting the radiant heat emanating from the outer wall of the stretching barrel toward the tube of film.
Claim 3
Dependent Claim
21 words
An apparatus set forth in claim 1, wherein the head portion of the preheater barrel has the structure of air curtain.
Claim 4
Dependent Claim
51 words
An apparatus set forth in claim 1, wherein the head portion has a plurality of circular sheets of a rubbery substance each having cuts formed from the center toward the circumference are layered in such way that the cuts iN each succeeding layer are staggered from those in the preceding layer.
Claim 5
Dependent Claim
46 words
An apparatus set forth in claim 1, wherein there is additionally incorporated below the cooling jacket a draft tube provided with an air-cooling ring adpated to effect suction of gas so as to establish a current of gas along the surface of the tube of film.
Claim 6
Dependent Claim
27 words
An apparatus set forth in claim 1, wherein there is additionally incorporated prior to the preheater barrel a means for giving preliminary heating to the raw film.
Claim 7
Dependent Claim
34 words
An apparatus set forth in claim 1, wherein there are additionally incorporated prior to the stretching barrel a plurality of slit heaters adapted to effect adjustment of the thickness of the tube of film.
Claim 8
Dependent Claim
27 words
An apparatus set forth in claim 4, wherein there is additionally incorporated prior to the preheater barrel a means for giving preliminary heating to the raw film.
Claim 9
Dependent Claim
34 words
An apparatus set forth in claim 4, wherein there are additionally incorporated prior to the stretching barrel a plurality of slit heaters adapted to effect adjustment of the thickness of the tube of film.
Claim 10
Dependent Claim
22 words
An apparatus set forth in claim 1, wherein there are additionally incorporated shielding plates within the preheater barrel and the stretching barrel.
Claim 11
Dependent Claim
22 words
An apparatus set forth in claim 4, wherein there are additionally incorporated shielding plates within the preheater barrel and the stretching barrel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |