US4409065A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Kraft paper
Assignee: ZEPA CONSULTING AG
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Filing: 1979-06-13
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Granted: 1983-10-11
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Expires: 1999-06-13
Abstract
Abstract Method for the production of kraft paper for increasing its functional quality, particularly its tensile energy absorption, whereby the pulp being prepared in a conventional manner is processed by additional separate curlation directly before web formation for increasing the elastic stretch and a paper bag made of that kraft paper wherein the elastic stretch exceeds 1.8%.
Inventors
- 👤 Alexander Kasser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:24
CPC Classifications
B; B65; B65D; B65D65/00; B65D65/38
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
136 words
In a method for the production of kraft paper comprising the steps of preparing the pulp in a conventional manner including beating or refining or treating the pulp in a Kollergang to produce a refined pulp, the improvement for producing kraft paper for heavy paper bags having increased tensile energy absorption and an elastic stretch exceeding 1.8%, comprising dewatering said refined pulp to a water content of substantially 20% to 60%, processing said dewatered pulp by separate curlation to curl the fibers to an average factor of curl exceeding 1.3, dispersing said curled pulp with water to a curled fiber content of approximately 0.09% to 0.21%, promptly forming a wet web from said pulp before the fibers restraighten, and drying the wet web while maintaining low tension so that the curl of the fiber is maintained.
Claim 2
Dependent Claim
136 words
In a method for the production of kraft paper comprising the steps of preparing the pulp in a conventional manner including beating or refining or treating the pulp in a Kollergang to produce a refined pulp, the improvement for producing kraft paper for heavy paper bags having increased tensile energy absorption and an elastic stretch exceeding 1.8%, comprising dewatering said refined pulp to a water content of substantially 20% to 60%, processing said dewatered pulp by separate curlation to curl the fibers to an average factor of curl exceeding 1.3, dispersing said curled pulp with water to a curled fiber content of approximately 0.09% to 0.21%, promptly forming a wet web from said pulp before the fibers restraighten, and drying the wet web while maintaining low tension so that the curl of the fiber is maintained.
Claim 3
Dependent Claim
135 words
In a method for the production of kraft paper comprising the steps of preparing the pulp in a conventional manner including beating or refining or treating the pulp in a Kollergang to produce a refined pulp, the improvement for producing kraft paper for light paper bags having increased tensile energy absorption and an elastic stretch exceeding 1.8%, comprising dewatering said refined pulp to a water content of substantially 20% to 60%, processing said dewatered pulp by separate curlation to curl the fibers to an average factor of curl exceeding 1.3, dispersing said curled pulp with water to a curled fiber content of less than 0.02% promptly forming a wet web from said pulp before the fibers re-straighten, and drying the wet web while maintaining low tension so that the curl of the fibers is maintained.
Claim 4
Dependent Claim
135 words
In a method for the production of kraft paper comprising the steps of preparing the pulp in a conventional manner including beating or refining or treating the pulp in a Kollergang to produce a refined pulp, the improvement for producing kraft paper for light paper bags having increased tensile energy absorption and an elastic stretch exceeding 1.8%, comprising dewatering said refined pulp to a water content of substantially 20% to 60%, processing said dewatered pulp by separate curlation to curl the fibers to an average factor of curl exceeding 1.3, dispersing said curled pulp with water to a curled fiber content of less than 0.02% promptly forming a wet web from said pulp before the fibers re-straighten, and drying the wet web while maintaining low tension so that the curl of the fibers is maintained.
Claim 5
Dependent Claim
16 words
Paper sack made of kraft paper according to claim 1 wherein the elastic stretch exceeds 1.8%.
Claim 6
Dependent Claim
16 words
Paper sack made of kraft paper according to claim 2 wherein the elastic stretch exceeds 1.8%.
Claim 7
Dependent Claim
25 words
Method according to claim 1 or claim 2 wherein said steps of preparing the pulp in a conventional manner comprises beating or refining the pulp.
Claim 8
Dependent Claim
26 words
Method according to claim 1 or claim 2 wherein the steps of preparing the pulp in a conventional manner comprises treating the pulp in a Kollergang.
Claim 9
Dependent Claim
26 words
Paper sack according to claim 3 or claim 4 wherein the weight per unit area of the kraft paper is at least 65 g/m 2 .
References Cited (Backward Citations)
US2516384A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-10 | 1987-04-11 | 1987-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-10 | 1991-04-11 | 1991-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-10 | 1995-04-11 | 1995-10-11 | $7700.00 | Window Closed / Lapsed |