US3485575A - Modification of linerboard to improve retention of stiffness - Google Patents
Modification of linerboard to improve retention of stiffness Download PDFInfo
- Publication number
- US3485575A US3485575A US528795A US3485575DA US3485575A US 3485575 A US3485575 A US 3485575A US 528795 A US528795 A US 528795A US 3485575D A US3485575D A US 3485575DA US 3485575 A US3485575 A US 3485575A
- Authority
- US
- United States
- Prior art keywords
- stiffness
- paperboard
- isocyanates
- solvent
- dimethylsulfoxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/03—Non-macromolecular organic compounds
- D21H17/05—Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
- D21H17/09—Sulfur-containing compounds
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
- D21J1/00—Fibreboard
Definitions
- a hydrocarbon liquid such as xylene, benzene or toluene is added a composition of an organic polyisocyanate and dimethyl sulfoxide to improve the humidity resisting characteristics thereof with respect to felted paperboard, i.e. linerboard.
- This invention relates to improvements in paperboard containers and relates in particular to a new and novel treatment of boxboard that materially enhances its stiffness retention properties.
- paperboard or boxboard which is a sandwichlike construction composed or corrugated, felted fiber sheets positioned between and glued to felted sheets known as paper-board (sometimes referred to as linerboard).
- Containers constructed of this material possess the requisite strength and durability for ordinary handling during shipping.
- the packaged goods are subjected to a highly humid environment, the pressed cellulosic fibers of the paperboard absorb moisture and swell. This action materially reduces the strength and stiffness retention properties of the paperboard and hence reduces the durability of the containers generally.
- Such moisture impregnated containers rapidly deteriorate and frequently disintegrated during handling exposing their contents to damage.
- a further object of the present invention is to improve the stiffness retention properties of folded boxboard containers used to package manufactured goods that are shipped and warehoused during commercial distribution.
- a still further object of the present invention is to treat paperboard and like felted materials with a polyisocyanate-dimethylsulfoxide-organic solvent solution that will improve the stiffness retention properties of such materials.
- the present invention consists of the discovery that when paperboard (textureboard-boxboard etc.) is contacted with a polyisocyanate-dimethylsulfoxide organic solvent solution that consists essentially of from 1 to 20 percent, by weight, of polyisocyanates and the solvent consists essentially of a mixture of dimethylsulfoxide and a second organic solvent within the ratio of from about 1:1 to 1:10 the paperboard acquires surprising stiffness and strength retention properties, even when exposed to a highly humid environment for extended periods of time.
- isocyanates including di-isocyanates-solvent solutions to waterproof and stiffen cellulosic materials
- Dimethylsulfoxide and benzene are known and useful solvents when applying isocyanates to cellulosic materials.
- Publications and patents such as U.S. Patents 2,339,913 and 3,007,763 reveal the use of these materials for waterproofing cloth.
- Isocyanates are compounds that contain the univalent radical NCO which is an isocyano group united with oxygen.
- the generic formulation is the following:
- Paperboard may be waterproofed with isocyanates in the conventional manner, however, such waterproofing does not materially enhance the stiffness retention properties of this material, particularly when it is exposed to a highly humid environment for an extended period of time.
- Cardboard specimens waterproofed in the usual manner by impregnation with solutions of isocyanates in benzene or isocyanates in dimethylsulfoxide exhibit only slightly improved stiffness retention properties when compared to untreated specimens.
- the stiffness retention properties are significantly enhanced.
- the isocyanates which we have found to be particularly effective in providing resistance to humid environments are the polyisocyanates.
- Polyisocyanates are commercially available materials usually found in a liquid form consisting of a polymer solution of a mixture of diisocyanates and triisocyanates plus small quantities of isocyanates and other impurities. We have found that treatment with solutions that are high in triisocyanate content provide optimum stiffness retention properties and hence the use of triisocyanates is a preferred embodiment of the present invention.
- the isocyanates utilized in the solution and process of the present invention are preferably polyisocyanates. Some substantially pure triisocyanates are available commercially and we have found that best results are obtained with these. A minimum of at least one percent, by weight, of the polyisocyanate is a prerequisite in obtaining significant improved stiffness retention.
- the polyisocyanates of the present invention may be alkyl or aryl polyisocyanates. Although there is no specific limit to the size or length of the radicals, it is preferred that the total number of carbon atoms of the isocyanate compounds not exceed about 33.
- Dimethylsulfoxide (CH SO is a well-known and powerful solvent which has exceptional penetrating powers. The low toxicity of this material reduces handling problems. It is a particularly good solvent for unsaturated hydrocarbons and aromatics such as the present isocyanates.
- isocyanate-dimethylsulfoxide waterproofing solutions employed for waterproofing cellulosic fibrous materials are well known, however, we have found that a second compatible solvent in amounts at least equal to the dimethylsulfoxide is necessary when such solutions are employed to impart significant humidity resistant stiffness to felted cellularosic materials.
- the minimum preferred dimethylsulfoxide content, for the solvent is one-tenth of the compatible solvent.
- the aforementioned compatible solvent may be any volatile organic liquid in which both the isocyanate and the dimethylsulfoxide are miscible and which is not reactive with either of these compounds. These requirements exclude the hydroxyl, amino, and carboxyl containing organic liquids since these reactive groups readily react with the unsaturated linkages of the isocyanates and/ or the dimethyl-sulfoxide molecules.
- Preferred compatible solvents are the aromatic liquids such as benzene, toluene, xylene, and their derivatives that are nonreactive with isocyanate and dimethyl-sulfoxide.
- Other particularly useful solvents are the aromatic ketones and esters.
- the specimens were contacted by the isocyanatesolvent solutions by immersing the 6 x 10" sections into the solutions in open glass trays or by positioning the specimens vertically and drawing down a glass rod over each surface on which the solution was deposited.
- the treated samples or sections were cut into strips one half inch wide and six inches long. These strips were stored for a minimum of one week under humid conditions (as indicated in the table below). One set of strips from each test solution was stored at 50 percent relative humidity, this being substantially a normal constant room temperature humidity. Other strips were stored for varying periods of time equivalent to or in excess of one week minimum time period.
- the ring crush test is regarded to be the most significant test for deter-mining the stiffness resistance of paperboard to highly humid environments. This test was conducted on an Instron Testing Machine (manufactured by the Instron Engineering Corporation, Canton, Mass.) in accordance with the TAPPI specifications Code No. T472M-51 relating to the compression resistance of paperboard (ring crush test). In this test a standard size strip of paperboard is mounted along one edge in a circular track (or slot) in a flat surface of a holder, forming a cylindrical protrusion six inches in circumference and /z-inch in height. Approximately fit-inch of the cylindrically shaped paperboard extends above the holder.
- the holder is seated in the tester so that the cylindrical shaped paperboard sample extends upwardly with its axis vertically disposed.
- An anvil mounted to the apparatus presses downwardly on the cylinder of paperboard until the paperboard buckles.
- the force required to effect such buckling is measured and reported in terms of pounds of force.
- Each figure in the data of the following table is the mean of several determinations using samples out both with, and across, the machine direction of the paper.
- Each test result reported in the table represents several ring crush tests conducted on specimens exposed to the reported humid conditions for a minimum of one week. It was determined substantially all of the loss of stiffness resistance occurred during one weeks exposure to humid conditions so that although some of the tests were conducted for periods longer than a week the comparativeness of the data is valid.
- Specimens treated with Wax exhibited stiffness retention property improvements under similar conditions of less than 200 percent. With the exception of one test wherein a formaldehyde pretreatment was employed, all of the polyisocyanate-dimethylsulfoxide-solvent treated specimens showed superior stiffness retention properties to the wax impregnated specimens.
Description
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US52879566A | 1966-02-21 | 1966-02-21 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3485575A true US3485575A (en) | 1969-12-23 |
Family
ID=24107217
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US528795A Expired - Lifetime US3485575A (en) | 1966-02-21 | 1966-02-21 | Modification of linerboard to improve retention of stiffness |
Country Status (1)
Country | Link |
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US (1) | US3485575A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3932209A (en) * | 1969-02-24 | 1976-01-13 | Personal Products Company | Low hemicellulose, dry crosslinked cellulosic absorbent materials |
US5038997A (en) * | 1990-02-26 | 1991-08-13 | Brown & Williamson Tobacco Corporation | Water resistant paperboard and method of making same |
US5292391A (en) * | 1991-04-29 | 1994-03-08 | Wyerhaeuser Company | Corrugated paperboard strength enhancing process |
US5332458A (en) * | 1991-04-29 | 1994-07-26 | Weyerhaeuser Co | Corrugated paperboard strength enhancing process |
US6620459B2 (en) | 2001-02-13 | 2003-09-16 | Houston Advanced Research Center | Resin-impregnated substrate, method of manufacture and system therefor |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3208875A (en) * | 1962-01-05 | 1965-09-28 | Du Pont | Method of making vapor permeable sheet materials |
-
1966
- 1966-02-21 US US528795A patent/US3485575A/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3208875A (en) * | 1962-01-05 | 1965-09-28 | Du Pont | Method of making vapor permeable sheet materials |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3932209A (en) * | 1969-02-24 | 1976-01-13 | Personal Products Company | Low hemicellulose, dry crosslinked cellulosic absorbent materials |
US5038997A (en) * | 1990-02-26 | 1991-08-13 | Brown & Williamson Tobacco Corporation | Water resistant paperboard and method of making same |
US5292391A (en) * | 1991-04-29 | 1994-03-08 | Wyerhaeuser Company | Corrugated paperboard strength enhancing process |
US5332458A (en) * | 1991-04-29 | 1994-07-26 | Weyerhaeuser Co | Corrugated paperboard strength enhancing process |
US6620459B2 (en) | 2001-02-13 | 2003-09-16 | Houston Advanced Research Center | Resin-impregnated substrate, method of manufacture and system therefor |
US20040063891A1 (en) * | 2001-02-13 | 2004-04-01 | Colvin John C. | Resin-impregnated substrate materials |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: NATIONAL WESTMINSTER BANK PLC Free format text: SECURITY INTEREST;ASSIGNOR:CONTAINER CORPORATION OF AMERICA;REEL/FRAME:004858/0656 Effective date: 19860930 Owner name: BANKERS TRUST COMPANY, 280 PARK AVENUE, NEW YORK, Free format text: SECURITY INTEREST;ASSIGNOR:CONTAINER CORPORATION OF AMERICA;REEL/FRAME:004858/0656 Effective date: 19860930 Owner name: CHEMICAL BANK Free format text: SECURITY INTEREST;ASSIGNOR:CONTAINER CORPORATION OF AMERICA;REEL/FRAME:004858/0656 Effective date: 19860930 Owner name: BANK OF NOVA SCOTIA, THE Free format text: SECURITY INTEREST;ASSIGNOR:CONTAINER CORPORATION OF AMERICA;REEL/FRAME:004858/0656 Effective date: 19860930 Owner name: MANUFACTURERS HANOVER TRUST COMPANY Free format text: SECURITY INTEREST;ASSIGNOR:CONTAINER CORPORATION OF AMERICA;REEL/FRAME:004858/0656 Effective date: 19860930 |