US3923943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for molding synthetic resin hollow articles
Assignee: Nissei Plastic Industrial Co Ltd
•
Filing: 1973-07-31
•
Granted: 1975-12-02
•
Expires: 1993-07-31
Abstract
Abstract This invention is concerned with a novel method for producing biaxially oriented hollow articles from a synthetic resin by blow molding of said resin at a temperature below the melting point of said resin which is characterized in that a parison of said resin is molded in a conventional manner, and that said parison is stretched in axial direction to a degree in which there exist in mixture oriented molecules and non-oriented molecules in said stretched direction, followed by a further stretching of said stretched parison with a pressurized gas.
Inventors
- 👤 Fumio Iriko
- 👤 Yoshihiko Yuzawa
- 👤 Setsuyuki Takeuchi
- 👤 Nobukuni Ibe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:15
CPC Classifications
B; B29; B29C; B29C49/00; B29C49/08; B29C49/10; B29C49/122; B29C49/1226; B29C49/42; B29C49/64; B29C49/6409; B29C49/12; B29C49/121; B29C49/1215
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
136 words
A MOLDING METHOD FOR PRODUCING A BIAXIALLY ORIENTED HOLLOW ARTICLE FROM A PARISON MADE OF A THERMOPLASTIC SYNTHETIC RESIN BY BLOWING THE AT A TEMPERATURE BELOW THE MELTING POINT OF SAID SYNTHETIC RESIN, WHICH IS CHARACTERIZED IN MECHANICALLY STRETCHING THE PARISON IN AN AXIAL DIRECTION AND INITIATING BLOW-MOLDING WITH A PRESSURIZED GAS DURING THE COURSE OF MECHANICAL STRETCHING AND BEFORE THE COMPLETION OF THE AXIAL UNIDIRECTIONAL ORIENTATION WHEREIN THE MECHANICAL STRETCHING IS EFFECTED AT A TEMPERATURE BELOW SAID MELTING POINT AT WHICH THE SYNTHETIC RESIN EXHIBITS A YIELD POINT AND A YIELD LIMIT, SAID BLOW MOLDING IS INTIATED WHEN THE PARISON HAS BEEN STRETCHED TO A LENGTH BETWEEN THE YIELD POINT AND YIELD LIMIT, AND WHEREIN SAID BLOW-MOLDING IS EFFECTED AT A HIGHER TEMPERATURE THAN THE MECHANICAL STRETCHING, WHEREBY AN ARTICLE OF IMPROVED TRANSPARENCY IS OBTAINED.
Claim 2
Dependent Claim
136 words
A MOLDING METHOD FOR PRODUCING A BIAXIALLY ORIENTED HOLLOW ARTICLE FROM A PARISON MADE OF A THERMOPLASTIC SYNTHETIC RESIN BY BLOWING THE AT A TEMPERATURE BELOW THE MELTING POINT OF SAID SYNTHETIC RESIN, WHICH IS CHARACTERIZED IN MECHANICALLY STRETCHING THE PARISON IN AN AXIAL DIRECTION AND INITIATING BLOW-MOLDING WITH A PRESSURIZED GAS DURING THE COURSE OF MECHANICAL STRETCHING AND BEFORE THE COMPLETION OF THE AXIAL UNIDIRECTIONAL ORIENTATION WHEREIN THE MECHANICAL STRETCHING IS EFFECTED AT A TEMPERATURE BELOW SAID MELTING POINT AT WHICH THE SYNTHETIC RESIN EXHIBITS A YIELD POINT AND A YIELD LIMIT, SAID BLOW MOLDING IS INTIATED WHEN THE PARISON HAS BEEN STRETCHED TO A LENGTH BETWEEN THE YIELD POINT AND YIELD LIMIT, AND WHEREIN SAID BLOW-MOLDING IS EFFECTED AT A HIGHER TEMPERATURE THAN THE MECHANICAL STRETCHING, WHEREBY AN ARTICLE OF IMPROVED TRANSPARENCY IS OBTAINED.
Claim 3
Dependent Claim
11 words
The molding method of claim 1 wherein said resin is polypropylene.
Claim 4
Dependent Claim
12 words
The molding method of claim 2 wherein said pressurized gas is air.
Claim 5
Dependent Claim
143 words
A molding method for producing a biaxially oriented hollow article from a parison made of a thermoplastic synthetic resin by blowing at a temperature below the melting point of said synthetic resin, which is characterized in mechanically stretching the parison in an axial direction and initiating blow-molding with a pressurized gas during the course of mechanical stretching and before the completion of the axial unidirectional orientation wherein said mechanical stretching is effected at a temperature below said melting point which does not exhibit a yield point, the blow-molding is effected at a temperature exhibiting a yield point and yield limit, and wherein said blow-molding is initiated when the parison has been stretched to a length which would be between said yield point and yield limit at said temperature exhibiting a yield point and yield limit, whereby an article of improved transparency is obtained.
Claim 6
Dependent Claim
143 words
A molding method for producing a biaxially oriented hollow article from a parison made of a thermoplastic synthetic resin by blowing at a temperature below the melting point of said synthetic resin, which is characterized in mechanically stretching the parison in an axial direction and initiating blow-molding with a pressurized gas during the course of mechanical stretching and before the completion of the axial unidirectional orientation wherein said mechanical stretching is effected at a temperature below said melting point which does not exhibit a yield point, the blow-molding is effected at a temperature exhibiting a yield point and yield limit, and wherein said blow-molding is initiated when the parison has been stretched to a length which would be between said yield point and yield limit at said temperature exhibiting a yield point and yield limit, whereby an article of improved transparency is obtained.
Claim 7
Dependent Claim
11 words
The molding method of claim 4 wherein said resin is polypropylene.
Claim 8
Dependent Claim
11 words
The molding method of claim 5 wherein said gas is air.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |