US4368218A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making expandable thermoplastic polymer beads
Assignee: Kanegafuchi Chemical Industry Co Ltd
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Filing: 1980-03-17
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Granted: 1983-01-11
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Expires: 2000-03-17
Abstract
Abstract Expandable thermoplastic polymer beads and method of producing same, wherein a core of a polymer of one or more vinyl monomers is substantially surrounded by a layer of a polyolefin comprising one or more vinyl monomers, with a foaming agent contained in at least the core.
Inventors
- 👤 Kenichi Senda
- 👤 Tatehiko Nishida
- 👤 Masao Nakagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:01
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/22; C08J9/224; C08F; C08F257/00; C08F257/02; C08F265/00; C08F265/04; C08J9/16; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2998
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
158 words
A method of producing expandable thermoplastic polymer beads, comprising the steps of suspending grains of a polymer made from one or more kinds of vinyl monomers, a powdered polyolefine resin, one or more kinds of vinyl monomers and a cross-linking agent into an aqueous medium containing a dispersing agent at a first temperature thereby to cause said vinyl monomer to impregnate said polymer and said resin and cause said resin to adhere to the surface of said grains of said polymer, and thereafter at a temperature higher than said first temperature, melting said resin onto the surface of said grain thereby forming a skin thereabout and concurrently polymerizing the resulting dispersin mixture in the presence of an initiator, thereby polymerising said monomer with said resin ins said skin, wherein a foaming agent is added to said dispersin mixture during or after polymerization, or said foaming agent is absorbed into grains of said polymer prior to start of polymerization.
Claim 2
Independent Claim
158 words
A method of producing expandable thermoplastic polymer beads, comprising the steps of suspending grains of a polymer made from one or more kinds of vinyl monomers, a powdered polyolefine resin, one or more kinds of vinyl monomers and a cross-linking agent into an aqueous medium containing a dispersing agent at a first temperature thereby to cause said vinyl monomer to impregnate said polymer and said resin and cause said resin to adhere to the surface of said grains of said polymer, and thereafter at a temperature higher than said first temperature, melting said resin onto the surface of said grain thereby forming a skin thereabout and concurrently polymerizing the resulting dispersin mixture in the presence of an initiator, thereby polymerising said monomer with said resin ins said skin, wherein a foaming agent is added to said dispersin mixture during or after polymerization, or said foaming agent is absorbed into grains of said polymer prior to start of polymerization.
Claim 3
Dependent Claim
24 words
The method of claim 1, wherein said grains of polymer are expandable polystyrene previously impregnated with said foaming agent prior to start of polymerization.
Claim 4
Dependent Claim
25 words
The method of claim 1 or 2, wherein said vinyl monomer is selected from the group consisting of styrene, methyl methacrylate, acrylonitrile and vinyl acetate.
Claim 5
Dependent Claim
51 words
The method of claim 1, 2, or 3, wherein the ratio of (A+B):C, is in the range of from 90:10 to 30:70, wherein "A" represents the weight of grains of said polymer, "B" represents the weight of said powdered polyolefine, and "C" represents the weight of one or more vinyl monomers.
Claim 6
Dependent Claim
23 words
The method of claim 1, wherein said cross-linking agent is selected from the group consisting of divinyl benzene, di-tert-butyl peroxide and dicumyl peroxide.
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) | 1986-01-10 | 1986-07-12 | 1987-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-10 | 1990-07-12 | 1991-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-10 | 1994-07-12 | 1995-01-11 | $7700.00 | Window Closed / Lapsed |