EP0408874A2
Expired / Lapsed
EP
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Process of molding thermoplastic sheet
Assignee: Idemitsu Petrochemical Co Ltd
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Filing: 1990-05-30
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Granted: —
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Expires: 2010-05-30
Abstract
Abstract This process of molding a thermoplastic sheet can be used for blister packaging. The process particularly includes the premolding step of bringing the sheet into close contact with the outer cylindrical surface of a molding drum, preheating the sheet and concurrently vacuum sucking the sheet into a cavity defined on the outer cylindrical surface of the drum; and the full-molding step of vacuum sucking the sheet and concurrently inserting the sheet into the cavity by means of a plug. The process can well mold a thermoplastic sheet including a layer of polypropylene.
Inventors
- 👤 Kouzaburo C/O Matsuzawa Co. Ltd. Matsuzawa
- 👤 Atsushi C/O Idemitsu Petrochemical Co. Ltd Fujii
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 00:48
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/18; B29C51/20; B29C51/22; B29C51/225; B29C51/26; B29C51/30; B29C51/04; B29C51/06; B29C51/08
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
105 words
A process of molding a thermoplastic sheet comprises the steps of: a premolding step with; bringing a thermoplastic sheet into close contact with the outer cylindrical surface of a molding drum, the molding drum having plural cavities whose each edge surface has a heat insulation layer, externally heating the thermoplastic sheet and concurrently vacuum sucking the thermoplastic sheet through the cavities of the molding drum; and a full-molding step with; vacuum sucking through the cavities of the molding drum the thermoplastic sheet with the pocket premolded in the cavity and concurrently full-molding the pocket by means of a plug, whereby the pocket is thermally molded.
Claim 2
Dependent Claim
105 words
A process of molding a thermoplastic sheet comprises the steps of: a premolding step with; bringing a thermoplastic sheet into close contact with the outer cylindrical surface of a molding drum, the molding drum having plural cavities whose each edge surface has a heat insulation layer, externally heating the thermoplastic sheet and concurrently vacuum sucking the thermoplastic sheet through the cavities of the molding drum; and a full-molding step with; vacuum sucking through the cavities of the molding drum the thermoplastic sheet with the pocket premolded in the cavity and concurrently full-molding the pocket by means of a plug, whereby the pocket is thermally molded.
Claim 3
Dependent Claim
31 words
A process of molding a thermoplastic sheet as recited in claim 1, wherein the thermoplastic sheet is fed under a tension of 0.2 kg/cm to 2.4 kg/cm into the molding drum.
Claim 4
Dependent Claim
23 words
A process of molding a thermoplastic sheet as recited in claim 2, wherein a brake roller or a dancer roller produces the tension.
Claim 5
Dependent Claim
59 words
A process of molding a thermoplastic sheet as recited in claim 1, wherein the degree of the vacuum through said premolding step is 400 mm Hg and the degree of the vacuum through said full-molding step is 600 mm Hg, the degree of the vacuum being defined as a value representing a degree of rarefaction below normal atmospheric pressure.
Claim 6
Dependent Claim
24 words
A process of molding a thermoplastic sheet as recited in claim 1, wherein the thermoplastic sheet comprises at least a layer made of polypropylene.
Claim 7
Dependent Claim
27 words
A process of molding a thermoplastic sheet as recited in claim 1, wherein a temperature of the molding drum is 30 degree Celsius to 80 degree Celsius.
Claim 8
Dependent Claim
40 words
A process of molding a thermoplastic sheet as recited in claim 1, wherein the molding drum is continuously rotated and a rotatable roll plug is inserted into the cavity of the molding drum to thereby fully mold the thermoplastic sheet.
Claim 9
Dependent Claim
27 words
A process of molding a thermoplastic sheet as recited in claim 7, wherein a continuous molding speed of the thermoplastic sheet is no more than 10 m/min.
Claim 10
Dependent Claim
27 words
A process of molding a thermoplastic sheet as recited in claim 7, wherein a temperature of the roll plug is 40 degree Celsius to 130 degree Celsius.
Claim 11
Dependent Claim
30 words
A process of molding a thermoplastic sheet as recited in claim 7, wherein the top surface of the roll plug is tapered toward the rotational direction of the roll plug.
Claim 12
Dependent Claim
90 words
A process of molding a thermoplastic sheet as recited in claim 7, wherein a clearance; between the front bottom edge of the roll plug and the leading edge surface of the cavity and a clearance; between the rear bottom edge of the roll plug and the trailing edge surface of the cavity are selected the thickness of the thermoplastic sheet from (the thickness of the thermoplastic sheet) to (the total of the thickness of the thermoplastic sheet and 250 µm), when the roll plug stays at its bottom dead center.
Claim 13
Dependent Claim
45 words
A process of molding a thermoplastic sheet as recited in claim 1, wherein the molding drum is intermittently rotated and a linearly reciprocating plug is inserted into the cavity of the molding drum when the molding drum stays to thereby full mold the thermoplastic sheet.
Claim 14
Dependent Claim
28 words
A process of molding a thermoplastic sheet as recited in claim 12, wherein a temperature of the linearly reciprocating plug is 20 degree Celsius to 50 degree Celsius.
Claim 15
Dependent Claim
44 words
A process of molding a thermoplastic sheet as recited in claim 12, wherein a cavity-entering speed of the linearly reciprocating plug is no less than 5 cm/sec and a stay time at bottom dead center through its motion is no less than 0.2 second.
Claim 16
Dependent Claim
93 words
A process of molding a thermoplastic sheet as recited in claim 12, wherein a clearance; between the front bottom edge of the linearly reciprocating plug and the leading edge surface of the cavity and a clearance; between the rear bottom edge of the linearly reciprocating plug and the trailing edge surface of the cavity are selected the thickness of the thermoplastic sheet from (the thickness of the thermoplastic sheet) to (the total of the thickness of the thermoplastic sheet and 250 µm), when the linearly reciprocating plug stays at its bottom dead center.
References Cited (Backward Citations)
No citation records indexed.
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