US3887670A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for and method of producing continuous foamed plastic bunstock
Assignee: Pharmacia and Upjohn Co
•
Filing: 1973-07-23
•
Granted: 1975-06-03
•
Expires: 1993-07-23
Abstract
Abstract Apparatus and method are described for improved production of foamed bunstock in continuous length. A generally U-shaped moving mold is utilized within which a thermosetting foam mix is deposited and the bunstock is then formed as a continuous block. This moving mold is configured along a critical portion of its length to conform as closely as practical to the inverted mirror image of the profile defined by the characteristic curve of percent of foam rise as a function of time for any selected foam mix composition. A weir arrangement is employed to control the travel of foam mix while this is still highly liquid. The objective is to maintain a condition of hydrostatic balance throughout the body of developing foam from the point of mix lay down to the point of foam gellation. Features of the invention reside in the concept of and means for changing the weir configuration and mold profile to achieve that condition of operation in which various forces acting on and in the developing foam mix produce the aforesaid hydrostatic equilibrium. By so doing greater flexibility is achieved in terms of ability to adapt a given production installation to handle different foam compositions, production rates, bunstock dimensions and shapes, with better uniformity of foam density and cell isotropicity than heretofore commercially practical.
Inventors
- 👤 Lawrence C Porter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:02
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/20; B29C44/28; Y; Y10; Y10S; Y10S264/00; Y10S264/84
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
269 words
A method of producing lonGitudinally continuous foamed bunstock from a reactive liquid polymeric mix to provide a continuous length expanded cellular product of substantially rectangular cross section, uniform density and cell isotropicity, which comprises the steps of advancing a continuous conveyor surface along a predetermined path of travel, said conveyor surface comprising a lower supporting portion and separate upstanding portions on laterally opposite sides of said lower portion and defining together a generally trough-like moving mold for the developing foam product; depositing reactive liquid polymer mix on said conveyor surface at a first point in its path of travel; advancing said conveyor surface in a generally horizontal plane with reacting liquid mix thereon to a second point along its path of travel; adjusting flow-impeding means disposed across said conveyor path intermediate said first and second points to produce a continuous pooling of said liquid mix therebetween to establish a stable cream line in the pooled liquid transversely of the path of travel and immediately ahead of said second point; adjusting the path travelled by the lower portion of said conveyor between said second point and a third point downstream thereof to conform said path approximately to the mirror image of the characteristic rise profile of the particular polymer mix developed in the time interval of conveyor travel between said second and third points, wherein said third point is adjustably positioned to substantially coincide with the point of maximum rise of the polymer foam; and thereafter continuing said conveyor surface travel from said third point through a curing zone to a point of discharge for the finished expanded cellular product.
Claim 2
Independent Claim
269 words
A method of producing lonGitudinally continuous foamed bunstock from a reactive liquid polymeric mix to provide a continuous length expanded cellular product of substantially rectangular cross section, uniform density and cell isotropicity, which comprises the steps of advancing a continuous conveyor surface along a predetermined path of travel, said conveyor surface comprising a lower supporting portion and separate upstanding portions on laterally opposite sides of said lower portion and defining together a generally trough-like moving mold for the developing foam product; depositing reactive liquid polymer mix on said conveyor surface at a first point in its path of travel; advancing said conveyor surface in a generally horizontal plane with reacting liquid mix thereon to a second point along its path of travel; adjusting flow-impeding means disposed across said conveyor path intermediate said first and second points to produce a continuous pooling of said liquid mix therebetween to establish a stable cream line in the pooled liquid transversely of the path of travel and immediately ahead of said second point; adjusting the path travelled by the lower portion of said conveyor between said second point and a third point downstream thereof to conform said path approximately to the mirror image of the characteristic rise profile of the particular polymer mix developed in the time interval of conveyor travel between said second and third points, wherein said third point is adjustably positioned to substantially coincide with the point of maximum rise of the polymer foam; and thereafter continuing said conveyor surface travel from said third point through a curing zone to a point of discharge for the finished expanded cellular product.
Claim 3
Independent Claim
77 words
A METHOD OF PRODUCING LONGITUDINALLY CONTINUOUS FOAMED BUNSTOCK FROM A REACTIVE LIQUID POLYMERIC MIX TO PROVIDE A CONTINUOUS LENGTH EXPANDED CELLULAR PRODUCT OF SUBSTANTIALLY RECTANGULAR CROSS SECTION, UNIFORM DENSITY AND CELL ISOTROPICITY, WHICH COMPRISES THE STEPS OF ADVANCING A CONTINUOUS CONVEYOR SURFACE ALONG A PREDETERMINED PATH OF TRAVEL, SAID CONVEYOR SURFACE COMPRISING A LOWER SUPPORTING PORTION AND SEPARATE UPSTANDING PORTIONS ON LATERALLY OPPOSITE TROUGH-LIKE MOVING MOLD FOR DEFINING TOGETHER A GENERALLY SIDES OF SAID LOWER PORTION AND
Claim 4
Independent Claim
77 words
A METHOD OF PRODUCING LONGITUDINALLY CONTINUOUS FOAMED BUNSTOCK FROM A REACTIVE LIQUID POLYMERIC MIX TO PROVIDE A CONTINUOUS LENGTH EXPANDED CELLULAR PRODUCT OF SUBSTANTIALLY RECTANGULAR CROSS SECTION, UNIFORM DENSITY AND CELL ISOTROPICITY, WHICH COMPRISES THE STEPS OF ADVANCING A CONTINUOUS CONVEYOR SURFACE ALONG A PREDETERMINED PATH OF TRAVEL, SAID CONVEYOR SURFACE COMPRISING A LOWER SUPPORTING PORTION AND SEPARATE UPSTANDING PORTIONS ON LATERALLY OPPOSITE TROUGH-LIKE MOVING MOLD FOR DEFINING TOGETHER A GENERALLY SIDES OF SAID LOWER PORTION AND
Claim 5
Dependent Claim
27 words
The method as defined in claim 1, which includes the step of varying the longitudinal positioning of said liquid flow-impeding means intermediate said first and second points.
Claim 6
Dependent Claim
22 words
The method as defined in claim 1, which includes positioning a series of liquid flow-impeding means intermediate said first and second point.
Claim 7
Dependent Claim
18 words
The method as defined in claim 3, which includes varying the height of the successive liquid flow-impeding means.
Claim 8
Dependent Claim
16 words
The method as defined in claim 1, which includes adjusting the height of said flow-impeding means.
Claim 9
Dependent Claim
33 words
The method as defined in claim 1, which includes the step of varying the length of travel of said lower conveyor surface between said second and third points in the path of travel.
Claim 10
Dependent Claim
53 words
The method as defined in claim 1, wherein the longitudinal positioning of said liquid flow-impeding means is varied intermediate said first and second points and wherein the slope of said lower conveyor surface portion relative to said opposed lateral portions is varied between said second and third points in the path of travel.
Claim 11
Dependent Claim
24 words
The method as defined in claim 7, wherein the length of travel of said conveyor surface between said second and third points is varied.
Claim 12
Independent Claim
216 words
The method of producing longitudinally continuous foamed bunstock from a reactive liquid polymeric mix to provide a continuous length expanded cellular product of substantially rectangular cross section, uniform denisty and cell isotropicity, which comprises the steps of advancing a continuous conveyor surface along a predetermined path of travel, said conveyor surface comprising a lower supporting portion and separate upstanding portions on laterally opposite sides of said lower portion and defining together a generally trough-like moving mold for the developing foam product; depositing reactive liquid polymer mix on said conveyor surface at a first point in its travel; advancing said conveyor surface in a generally horizontal plane with reacting liquid mix thereon to a second point along its path of travel; adjusting the path traveled by the lower portion of said conveyor between said second point and a third point downstream thereof to conform approximately to the mirror image of the characterIstic rise profile of the particular polymer mix developed in the time interval of conveyor travel between said second and third points, wherein said third point is adjustably positioned to substantially coincide with the point of maximum rise of the polymer foam; and thereafter continuing said conveyor surface travel from said third point through a curing zone to a point of discharge for the finished product.
Claim 13
Independent Claim
216 words
The method of producing longitudinally continuous foamed bunstock from a reactive liquid polymeric mix to provide a continuous length expanded cellular product of substantially rectangular cross section, uniform denisty and cell isotropicity, which comprises the steps of advancing a continuous conveyor surface along a predetermined path of travel, said conveyor surface comprising a lower supporting portion and separate upstanding portions on laterally opposite sides of said lower portion and defining together a generally trough-like moving mold for the developing foam product; depositing reactive liquid polymer mix on said conveyor surface at a first point in its travel; advancing said conveyor surface in a generally horizontal plane with reacting liquid mix thereon to a second point along its path of travel; adjusting the path traveled by the lower portion of said conveyor between said second point and a third point downstream thereof to conform approximately to the mirror image of the characterIstic rise profile of the particular polymer mix developed in the time interval of conveyor travel between said second and third points, wherein said third point is adjustably positioned to substantially coincide with the point of maximum rise of the polymer foam; and thereafter continuing said conveyor surface travel from said third point through a curing zone to a point of discharge for the finished product.
Claim 14
Dependent Claim
33 words
The method as defined in claim 9, which includes the step of varying the length of travel of said lower conveyor surface between said second and third points in the path of travel.
Claim 15
Dependent Claim
44 words
A method as defined in claim 9, which includes the step of varying the rate of downward shifting of said lower supporting portion of said conveyor surface relative to said lateral portions between said second and third points in the path of conveyor travel.
Claim 16
Independent Claim
168 words
A method of producing longitudinally continuous foamed bunstock from a reactive liquid polymeric mix, which comprises the steps of advancing a continuous conveyor surface along a predetermined path of travel from a point of liquid mix lay down to a point of discharge of finished product, said conveyor surface comprising a lower supporting portion and separate upstanding portion on laterally opposite sides of said lower portion and defining together a generally trough-like moving mold for the developing foam product; depositing reactive polymer mix on said conveyor surface at a first point comprising said point of liquid mix lay down; advancing said conveyor surface in a generally horizontal plane with reacting liquid mix thereon to a second point along its path of travel; adjusting weir means disposed transversely of the conveyor path intermediate said first and second points and causing said lower support conveyor portion to travel over said transversely disposed weir means to thereby provide a variably positionable flow-impeding rise in its path of travel between said points.
Claim 17
Independent Claim
168 words
A method of producing longitudinally continuous foamed bunstock from a reactive liquid polymeric mix, which comprises the steps of advancing a continuous conveyor surface along a predetermined path of travel from a point of liquid mix lay down to a point of discharge of finished product, said conveyor surface comprising a lower supporting portion and separate upstanding portion on laterally opposite sides of said lower portion and defining together a generally trough-like moving mold for the developing foam product; depositing reactive polymer mix on said conveyor surface at a first point comprising said point of liquid mix lay down; advancing said conveyor surface in a generally horizontal plane with reacting liquid mix thereon to a second point along its path of travel; adjusting weir means disposed transversely of the conveyor path intermediate said first and second points and causing said lower support conveyor portion to travel over said transversely disposed weir means to thereby provide a variably positionable flow-impeding rise in its path of travel between said points.
Claim 18
Dependent Claim
21 words
The method as defined in claim 12, which includes imposing a series of flow-impeding rises between said first and second points.
References Cited (Backward Citations)
US3476845A
Cited
US3560599A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |