US4104357A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of rotational molding about plural axes at low rotational speeds
Assignee: Monster Molding Inc
•
Filing: 1974-05-17
•
Granted: 1978-08-01
•
Expires: 1994-05-17
Abstract
Abstract Low speed rotational molding of plastic objects at about ambient temperatures from a liquid thermosetting plastic material distributed in a mold substantially under gravitational force; the selected thermosetting plastic is placed as a distributable liquid in a mold having a volume much larger than the volume of the liquid polymer and slowly rotated about two axes at or about room temperature; urethane polymers to which a quantity of diamine curing agent has been added prior to the introduction of the flowable plastic into the rotatable mold are typical thermosetting materials; useful objects or shapes having thin, relatively uniform walls are produced by the disclosed process; repetition of molding steps allows the build up of same or different layers which may have interposed therebetween, lightening, stiffening, and/or strengthening members; precoating of a mold with a variety of coatings which release, interact, or decorate the thermoset resin surface is also disclosed.
Inventors
- 👤 Edgar Allan Blair
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:52
CPC Classifications
B; B29; B29C; B29C41/00; B29C41/02; B29C41/04; B29C41/06; B29C41/003; B29C41/22; B29K; B29K2101/00; B29K2101/10
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
180 words
A process for low rotational velocity molding at a temperature of less than 100° C of a shape comprising the successive steps of: (a) mixing a liquid thermosetting polymer or a liquid polymer with a curing agent capable of hardening said thermosetting polymer or pre-polymer at ambient temperatures, and placing the resulting liquid mixture into a mold; (b) moving said mold, said moving consisting of rotating said mold about two axes at such low rotational velocity, at ambient temperatures such that the centrifugal force on said mixture is negligible and adjusting the rotational velocity about each axis such that, upon observation, a uniform distribution of said polymer is obtained; (c) maintaining the polymer while thus rotating said mold substantially under gravitational force influence with respect to said axes causing said mixture to distribute uniformly over and to coat the walls of said mold taking the form thereof without accumulation of said polymer due to centrifugal force; (d) continuing said rotation until said liquid mixture hardens to a solid shape; and (e) removing the solid shape thus produced from said mold.
Claim 2
Dependent Claim
180 words
A process for low rotational velocity molding at a temperature of less than 100° C of a shape comprising the successive steps of: (a) mixing a liquid thermosetting polymer or a liquid polymer with a curing agent capable of hardening said thermosetting polymer or pre-polymer at ambient temperatures, and placing the resulting liquid mixture into a mold; (b) moving said mold, said moving consisting of rotating said mold about two axes at such low rotational velocity, at ambient temperatures such that the centrifugal force on said mixture is negligible and adjusting the rotational velocity about each axis such that, upon observation, a uniform distribution of said polymer is obtained; (c) maintaining the polymer while thus rotating said mold substantially under gravitational force influence with respect to said axes causing said mixture to distribute uniformly over and to coat the walls of said mold taking the form thereof without accumulation of said polymer due to centrifugal force; (d) continuing said rotation until said liquid mixture hardens to a solid shape; and (e) removing the solid shape thus produced from said mold.
Claim 3
Dependent Claim
27 words
The process as defined in claim 1 wherein said thermosetting polymer is selected from the group consisting of polyurethanes, polyesters, epoxides, silicones, phenolics, urea-formaldehyde, and melamine formaldehyde.
Claim 4
Dependent Claim
14 words
The process as defined in claim 1 wherein said thermosetting polymer is a polysulfide.
Claim 5
Dependent Claim
27 words
The process as defined in claim 1 wherein said curing agent is selected from the group consisting of a diamine, a polyamine, polyhydroxy compounds and a peroxide.
Claim 6
Dependent Claim
21 words
A process according to claim 1 wherein said thermosetting polymer is Adiprene L 100 and said curing agent is 4,4'-methylene bis(2-chloroaniline).
Claim 7
Dependent Claim
21 words
A process according to claim 1 wherein said thermosetting polymer is a polyester resin, and the curing agent is a peroxide.
Claim 8
Dependent Claim
14 words
A process according to claim 1 wherein said thermosetting polymer contains an inert filler.
Claim 9
Dependent Claim
20 words
A process according to claim 1 wherein said mold zone is polyester fiberglass, epoxy-fiberglass, plaster, wood, cardboard, papier-mache, or rubber.
Claim 10
Dependent Claim
11 words
A process according to claim 8 wherein said mold is polyester-fiberglass.
Claim 11
Dependent Claim
11 words
A process according to claim 8 wherein said mold is wood.
Claim 12
Dependent Claim
11 words
A process according to claim 8 wherein said mold is plaster.
Claim 13
Dependent Claim
11 words
A process according to claim 8 wherein said mold is cardboard.
Claim 14
Dependent Claim
11 words
A process according to claim 8 wherein said mold is papier-mache.
Claim 15
Dependent Claim
12 words
A process according to claim 8 wherein said mold is flexible rubber.
Claim 16
Dependent Claim
160 words
A process for low rotational velocity molding at ambient temperatures or up to 1000° C of an object or shape comprising: (a) mixing a liquid thermosetting polymer or a liquid prepolymer with a cursing agent capable of hardening the thermosetting polymer or prepolymer at ambient temperatures to form a thermosetting polymer system, and placing the resulting liquid polymer system into a mold, in combination with (b) moving said mold, said moving consisting of rotating said mold about two axes at such low rotational velocity, at ambient temperatures such that the centrifugal force on said mixture is negligible and adjusting the rotational velocity about each axis such that, upon observation, a uniform distribution of said polymer is obtained thereby causing the polymer system to be distributed uniformly over and to coat the walls of the mold taking the form thereof, and continuing the rotation until the liquid polymer system hardens, and (c) removing a solid shape thus produced from the mold.
Claim 17
Dependent Claim
160 words
A process for low rotational velocity molding at ambient temperatures or up to 1000° C of an object or shape comprising: (a) mixing a liquid thermosetting polymer or a liquid prepolymer with a cursing agent capable of hardening the thermosetting polymer or prepolymer at ambient temperatures to form a thermosetting polymer system, and placing the resulting liquid polymer system into a mold, in combination with (b) moving said mold, said moving consisting of rotating said mold about two axes at such low rotational velocity, at ambient temperatures such that the centrifugal force on said mixture is negligible and adjusting the rotational velocity about each axis such that, upon observation, a uniform distribution of said polymer is obtained thereby causing the polymer system to be distributed uniformly over and to coat the walls of the mold taking the form thereof, and continuing the rotation until the liquid polymer system hardens, and (c) removing a solid shape thus produced from the mold.
Claim 18
Dependent Claim
28 words
The process as defined in claim 15 and wherein the polymer system is placed in said mold at least one additional time and steps (b) and (c) repeated.
Claim 19
Dependent Claim
51 words
The process as defined in claim 16 wherein a reinforcing member is placed in the mold after the first placing of the polymer system in the mold and a predetermined amount of said polymer system is placed in said mold at least one additional time and steps (b) and (c) repeated.
Claim 20
Dependent Claim
152 words
A process for low rotational velocity molding of plastic articles at about ambient temperature comprising: mixing a liquid thermosetting polymer or a liquid thermosetting prepolymer with a curing agent into a liquid mixture, placing a predetermined quantity of said liquid mixture into a mold having a volume greatly larger than the volume of said mixture, moving said mold, said moving consisting of rotating said mold about two axes at such low rotational velocity, at ambient temperatures such that the centrifugal force on said mixture is negligible and adjusting the rotational velocity about each axis such that, upon observation, a uniform distribution of said polymer is obtained thereby coating the entire surface of said mold at a substantially uniform thickness, continuing said rotation at about ambient temperature until said liquid mixture gels and cures in the form resembling the inside of said mold, and removing the solid article thus formed from said mold.
Claim 21
Dependent Claim
152 words
A process for low rotational velocity molding of plastic articles at about ambient temperature comprising: mixing a liquid thermosetting polymer or a liquid thermosetting prepolymer with a curing agent into a liquid mixture, placing a predetermined quantity of said liquid mixture into a mold having a volume greatly larger than the volume of said mixture, moving said mold, said moving consisting of rotating said mold about two axes at such low rotational velocity, at ambient temperatures such that the centrifugal force on said mixture is negligible and adjusting the rotational velocity about each axis such that, upon observation, a uniform distribution of said polymer is obtained thereby coating the entire surface of said mold at a substantially uniform thickness, continuing said rotation at about ambient temperature until said liquid mixture gels and cures in the form resembling the inside of said mold, and removing the solid article thus formed from said mold.
Claim 22
Dependent Claim
55 words
The process as defined in claim 18 wherein the speed of rotation of said mold about each of two mutually perpendicular axes is sufficient to cause said liquid mixture to flow evenly and completely over the entire surface of said mold with negligible effect of centrifugal force on said mixture with respect to said axes.
Claim 23
Dependent Claim
19 words
Process as claimed in claim 19 wherein the speed of rotation of each of said axes is mutually independent.
Claim 24
Dependent Claim
39 words
Process as claimed in claim 19 wherein the speed of rotation of said mold about each of said two mutually perpendicular axes is less than that at which centrifugal rotational forces disturb the substantially uniform thickness of said coating.
Claim 25
Dependent Claim
172 words
In a process for forming plastic articles, the steps comprising: (a) mixing a thermosetting polymer or a prepolymer with a curing agent therefor into a liquid mixture; (b) introducing a predetermined quantity of said liquid mixture into a mold for coating the mold surface of a thickness of less than 1/4 inch; (c) distributing uniformly under substantially gravitational influence only a mixture as a coating on the mold surface by moving said mold, said moving consisting of rotating said mold about two axes at such low rotational velocity, at ambient temperatures such that the centrifugal force on said mixture is negligible and adjusting the rotational velocity about each axis such that, upon observation, a uniform distribution of said polymer is obtained; (d) said mixture reacting under an exothermic gelling reaction as the mold is slowly rotated; (e) transmitting heat generated by said exothermic reaction to the mold, said mold acting as a heat sink; (f) continuing said slow rotation as the thermosetting resin hardens, and (g) removing said article from said mold.
Claim 26
Dependent Claim
172 words
In a process for forming plastic articles, the steps comprising: (a) mixing a thermosetting polymer or a prepolymer with a curing agent therefor into a liquid mixture; (b) introducing a predetermined quantity of said liquid mixture into a mold for coating the mold surface of a thickness of less than 1/4 inch; (c) distributing uniformly under substantially gravitational influence only a mixture as a coating on the mold surface by moving said mold, said moving consisting of rotating said mold about two axes at such low rotational velocity, at ambient temperatures such that the centrifugal force on said mixture is negligible and adjusting the rotational velocity about each axis such that, upon observation, a uniform distribution of said polymer is obtained; (d) said mixture reacting under an exothermic gelling reaction as the mold is slowly rotated; (e) transmitting heat generated by said exothermic reaction to the mold, said mold acting as a heat sink; (f) continuing said slow rotation as the thermosetting resin hardens, and (g) removing said article from said mold.
Claim 27
Dependent Claim
19 words
The process as defined in claim 22 wherein the viscosity of said thermosetting polymer is less than 50,000 cps.
Claim 28
Dependent Claim
19 words
The process as defined in claim 23 wherein the viscosity of said thermosetting polymer is less than 50,000 cps
Claim 29
Dependent Claim
23 words
The process as defined in claim 22 wherein the mold is precoated with a catalyst for said thermosetting polymer and the curative therefor.
Claim 30
Dependent Claim
22 words
The process as defined in claim 22 wherein the mold is precoated with a coating to which said thermosetting polymer adhesively adheres.
Claim 31
Dependent Claim
24 words
The process as defined in claim 22 and wherein the polymer is introduced in said mold in portions and each portion is hardened individually.
Claim 32
Dependent Claim
27 words
The process as defined in claim 27 and wherein a reinforcing component for said thermosetting polymer is introduced in said mold between two portions of said polymer.
Claim 33
Dependent Claim
39 words
The process according to claim 27 and wherein a foam member is introduced in said mold and attached to said first portion of said polymer and thereafter an additional portion of said thermosetting polymer is introduced in said mold.
Claim 34
Dependent Claim
24 words
The process as defined in claim 27 and wherein the first portion of said thermosetting polymer has incorporated therein light stabilizers for said polymer.
Claim 35
Dependent Claim
18 words
The process as defined in claim 22 and wherein said mold is precoated with a mold release agent.
Claim 36
Dependent Claim
17 words
The process as defined in claim 22 and wherein a diluent is incorporated in said thermosetting polymer.
References Cited (Backward Citations)
US1998897A
Cited
US2030200A
Cited
US2558807A
Cited
US2837769A
Cited
US3222439A
Cited
US3347971A
Cited
US3337662A
Cited
GB1136166A
Cited
US3420729A
Cited
US3414456A
Cited
US3410934A
Cited
US3427689A
Cited
US3507950A
Cited
US3539659A
Cited
US3629206A
Cited
US3714312A
Cited
US3694530A
Cited
US3683062A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-31 | 1982-01-30 | 1982-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-31 | 1986-01-30 | 1986-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-31 | 1990-01-30 | 1990-08-01 | $7700.00 | Window Closed / Lapsed |