Patent US3833897A successfully refreshed from Google Patents.
Patent US3725520A successfully refreshed from Google Patents.
US3725520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for preparing a porous synthetic thermoplastic film or sheet
Assignee: Sanyo Kokusaku Pulp Co Ltd
•
Filing: 1970-04-24
•
Granted: 1973-04-03
•
Expires: 1990-04-24
Abstract
Abstract A method for preparing a porous film or sheet, which comprises admixing together 100 parts by volume of at least one thermoplastic resin, 5 - 150 parts by volume of a solvent, and 20-50 parts by volume of a filler, uniformly dispersing the solvent and the filler in said resin to thereby form a stock, molding a film or sheet from the resulting stock, biaxially stretching the film or sheet at a suitable temperature between the glass transition temperature of the resin and the flow temperature of the resin, and substantially removing the solvent from the film or sheet during the period between the molding and the end of the stretching without foaming.
Inventors
- 👤 S Suzuki
- 👤 K Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:05
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/02; B29C55/10; B29C55/12; B29C67/00; B29C67/20; B29C67/202; C; C08; C08J; C08J9/00; C08J9/28; D; D01; D01F; D01F1/00; D01F1/02; D01F1/10; C08J2201/00; C08J2201/04; C08J2201/05; C08J2201/0502; Y; Y10; Y10S; Y10S264/00; Y10S264/13; Y10S264/17; Y10S264/62; Y10S428/00; Y10S428/91
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
204 words
A method for preparing a porous film or sheet, whIch comprises: A. admixing together: 100 parts by volume of at least one thermoplastic resin, 5-150 parts by volume of a solvent, and 20-50 parts by volume of a filler, B. uniformly dispersing the solvent and the filler in said resin to thereby form a stock, C. molding a film or sheet from the resulting stock, D. biaxially stretching the film or sheet at a suitable temperature between the glass transition temperature of the resin and the flow temperature of the resin, and E. substantially entirely removing the solvent from the film or sheet during the period between the molding and the end of the stretching without foaming, the aforesaid steps being further characterized by the facts that: a. said at least one thermoplastic resin is selected from the group consisting of polyolefins, polyvinyls, polyamides, and polyesters, b. said solvent has a boiling point between 100* and 230*C., c. said solvent is incapable of completely dissolving the resin of (a) at the temperature of molding step (C), but capable of partially swelling the resin, d. said filler is inert to the resin of (a), and e. said filler is stable at the temperature of molding.
Claim 2
Dependent Claim
52 words
a solvent mixture containing at least 60 percent by volume of xylene with the balance being a solvent selected from the group consisting of chlorobenzene, dichlorobenzene, ethylbenzene, diethyl-benzene, decalin, tetralin, terpene oil, chlorinated hydrocarbons having a boiling point of 100* - 230*C and a mixture of at least two of these solvents,
Claim 3
Dependent Claim
98 words
A method according to claim 2 wherein said thermoplastic resin is a polyolefin and said solvent is selected from the group consisting of (a) petroleum- and coal- naphtha containing at least 50 percent by volume of aromatic components and having a boiling point of 160*-230*C and (b) a solvent mixture containing at least 60 percent by volume of xylene, with the balance being a solvent selected from the group consisting of chlorobenzene, dichlorobenzene, ethylbenzene, diethylbenzene, decalin, tetralin, terpene oil, chlorinated hydrocarbons having a boiling point of 100* -230*C and a mixture of at least two of these solvents.
Claim 4
Dependent Claim
62 words
a solvent mixture containing at least 70 percent by volume of a solvent from the group of petroleum naphtha, coal naphtha having a boiling point of 150*-230*C., xylene and a mixture of these two solvents with the balance being a solvent selected from the group consisting of cyclohexanone, nitrobenzene, diacetone alcohol and a mixture of at least two of these compounds and
Claim 5
Dependent Claim
93 words
water, c. said solvent is incapable of completely dissolving the resin of (a) at the temperature of molding step (C), but capable of partially swelling the resin, d. said filler is inert to the resin of (a) and stable at the temperature of molding and comprises at least one member selected from the group consisting of calcium carbonate, magnesium carbonate, barium sulfate, powdered silica, mica, kaolin, clay, diatomaceous earth, talc, gypsum, asbestos, rock wool, alumina, aluminum hydroxide, powdered glass, glass fiber, white carbon, titanium dioxide, pulp floc,wood sawdust, and synthetic polymer short fibers.
Claim 6
Dependent Claim
84 words
A method according to claim 2 wherein said thermoplastic resin is a polyvinyl resin and said solvent is selected from mixtures containing at least 70 percent by volume of a solvent selected from the group consisting of petroleum-and coal-naphtha having a boiling point of 150* - 230*C, xylene and a mixture of at least two of these solvents, with the remainder being a solvent selected from the group consisting of cyclohexanone, nitrobenzene, diacetone alcohol and a mixture of at least two of these compounds.
Claim 7
Dependent Claim
35 words
A method according to claim 2 wherein said thermoplastic resin is polystrene and said solvent is selected from the group consisting of petroleum- and coal- solvent naphtha having a boiling point of 130* - 230*C.
Claim 8
Dependent Claim
58 words
A method according to claim 2, wherein the filler is at least one member selected from the group consisting of calcium carbonate, magnesium carbonate, barium sulfate, powdered silica, mica, kaolin, clay, diatomaceous earth, talc, gypsum, asbestos, rock wool, alumina, aluminum hydroxide, powdered glass, glass fiber, white carbon, titanium dioxide, pulp floc, wood sawdust, and synthetic polymer short fibers.
Claim 9
Dependent Claim
43 words
A method according to claim 2 wherein the biaxially stretched air-permeable film or sheet is thereafter coated with a final thermoplastic polymeric resin having a higher Young''s modulus than that of the thermoplastic polymeric resin that was used to form the stretched film.
Claim 10
Dependent Claim
14 words
A method according to claim 7 wherein said final thermoplastic polymeric resin is polystyrene.
Claim 11
Dependent Claim
15 words
A method according to claim 7 wherein said final thermoplastic polymeric resin is polyvinyl alcohol.
Claim 12
Dependent Claim
18 words
A method according to claim 6 wherein said final thermoplastic polymeric resin is admixed with an antistatic agent.
Claim 13
Dependent Claim
14 words
A method according to claim 10 wherein said antistatic agent is an anionic surfactant.
References Cited (Backward Citations)
US2312623A
Cited
US2360650A
Cited
US2987774A
Cited
US2979774A
Cited
US3154461A
Cited
US3042972A
Cited
FR1333302A
Cited
US3256374A
Cited
US3351569A
Cited
US3327033A
Cited
US3320328A
Cited
US3426754A
Cited
US3470277A
Cited
US3486946A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |