WO1999023308A1 - High speed coating apparatus and method - Google Patents
High speed coating apparatus and method Download PDFInfo
- Publication number
- WO1999023308A1 WO1999023308A1 PCT/US1998/018107 US9818107W WO9923308A1 WO 1999023308 A1 WO1999023308 A1 WO 1999023308A1 US 9818107 W US9818107 W US 9818107W WO 9923308 A1 WO9923308 A1 WO 9923308A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- roll
- coating material
- web
- enclosed
- coater
- Prior art date
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
- D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
- D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
- D21H23/22—Addition to the formed paper
- D21H23/52—Addition to the formed paper by contacting paper with a device carrying the material
- D21H23/56—Rolls
-
- 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
- D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
- D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
- D21H23/22—Addition to the formed paper
- D21H23/52—Addition to the formed paper by contacting paper with a device carrying the material
- D21H23/56—Rolls
- D21H23/58—Details thereof, e.g. surface characteristics, peripheral speed
Definitions
- This invention relates to high speed application of liquid coating material to a paper web.
- the invention relates to utilizing several application stages to apply a uniform coating layer.
- a flooded nip coater One type of applicator apparatus that has been used for a considerable length of time is known as a flooded nip coater.
- This type of coater includes an applicator roll which rotates in a pan of coating material thereby picking up the coating onto the applicator roll and transferring the coating film to a web sheet as it travels on the surface of a backing roll.
- the applicator roll and the sheet move in the same direction and the coating is applied to the sheet at a small gap between the sheet and the applicator roll.
- the high speed of applicator roll in the pan causes splashing of the coating material and pond instability and consequent lack of uniformity in applying the coating to the sheet. Also, if the sheet breaks, broke may collect in the applicator pan resulting in increased cleanup work and downtime.
- a short dwell applicator has an enclosed type of pond of coating material which eliminates the problem of broke collecting in an open pan or pond. It also eliminates the splashing and turbulence of an open pan.
- unstable vortices in the pond immediately adjacent the web being coated form due to the high speed of the web as it passes the pond of coating material. With high viscosity coating materials and as speed increases, coating defects in the form of streaks and blotchy patterns appear on the paper web.
- An effort to solve this problem has been to provide a low angle premetering blade to minimize the unstable vortices and help expel air that is brought in with the passing web. Although this improvement has improved the quality of coating, the basic problem still persists.
- a jet coating applicator which includes an enclosure and a coating applicator nozzle through which coating material is applied to a passing web. Due to the enclosed nature of the jet applicator, there is no turbulence of an open pan or broke falling into the pan. However, there is a high speed turbulence problem in that the high speed of a passing web causes turbulence in the coating material as it is applied to the web causing breakup and non-uniformity of the coating.
- the present invention is directed to a further improvement in the coating process which will permit coating at high speeds using high viscosity coating materials without the turbulence resulting in coating quality defects.
- the invention is carried out in a coating apparatus in which a paper web is advanced at a relatively high speed with a backing roll which provides a backup surface for the web as it advances.
- An enclosed coater applies coating material to a roll applicator which is rotating at a slow linear speed relative to the speed of the web.
- the coating material applied to the roll applicator by the coater is, in turn, applied to the web by the roll applicator moving at the slower speed relative to the web speed.
- the coating material is applied to the web at a spacing gap between the roll applicator and the web on the backing roll with which the web is advancing.
- the use of the enclosed coater eliminates an open pan which may produce turbulence and splashing and also the possibility of broke falling into the pan.
- the application of the coating material by the enclosed coater to a roll applicator moving at a slow speed eliminates the breakup in the coating material due to turbulence at the web or roll surface or the vortice type turbulence, both associated with applying coating material with an enclosed coater to a web or roll moving at high speed.
- the application of the coating material by the roll applicator to the web wherein the roll applicator is moving at a slower speed relative to that of the web also eliminates turbulence in such application and permits a uniform coating of material to be applied to the web.
- the thickness of the coating material applied to the web is controlled by controlling or metering the amount of coating material applied from the enclosed coater to the roll applicator. Utilizing an enclosed coater for controlling the amount of coating material applied to the web permits greater precision in controlling the thickness of the coating on the web than can be obtained with the common method using a doctor. Also, the enclosed coater can be used to vary the thickness of the coating applied to the web across the width of the web.
- Fig. 1 is an end elevation schematic view of the coating apparatus according to the invention.
- Fig. 2 is a side elevation schematic view of the invention shown in Fig. 2;
- Fig. 3 is an end elevation schematic view, partially in cross-section, of one embodiment of an enclosed coater utilized in the invention.
- Fig. 4 is an end elevation schematic view, partially in cross-section, of an alternate embodiment of the invention.
- a web coating apparatus 2 is shown in Figs. 1 and 2.
- the web coating apparatus 2 includes a roll 4 having a circumferential surface 14 and which rotates in the direction of arrow 8 about an axis 6.
- the embodiment of the invention shown in Figs. 1 and 2, and also in Fig. 3, includes an enclosed coating applicator 20 which is of an enclosed pond type of applicator.
- Enclosed coating applicators of the enclosed pond type are well-known in the papermaking industry for coating of continuously moving paper webs.
- Such enclosed pond coating applicators include blades, smooth rods and grooved rods for metering and controlling the coating material applied to the web.
- an enclosed pond coating applicator utilizing a blade metering device is utilized, but it should be understood that other types of enclosed pond applicators including those mentioned above are also suitable.
- the enclosed applicator 20 applies coating material 22 to a roll applicator 30.
- the roll applicator 30 has a circumferential surface 32 onto which the coating material 22 is applied by the enclosed applicator 20 and rotates about an axis 34 in the direction of arrow 36.
- the direction of rotation of the roll applicator 30 immediately opposite the roll 4 and web 10 is thus in the same direction as the advancing movement of the web 10 and the rotation of the roll 4.
- the roll applicator 30 forms a gap 38 with the web 10 and roll 30 in the area at which the web 10 and roll 30 are most adjacent to each other.
- the enclosed applicator 20 includes a tube 24 through which coating material 22 is delivered by a pump (not shown).
- the coating material 22 moves through the tube 24 into a chamber 26 of the applicator 20 which contains a pond 44 of coating material 22.
- the chamber 26 has walls formed by member 28, a premetering element 29, a metering blade 42 of a metering mechanism 40 and a portion of the circumferential surface 32 of the roll applicator as it moves past the enclosed applicator 20.
- the applicator 20 has a width parallel to the axis 34 of the roll 30 at least the width w of the web 10 and a plurality of metering mechanisms 40 mounted along this width
- the roll 4 and paper web 10 travel at a relatively high linear speed which may be, for example, in the range of 200 to 3000 meters per minute.
- the roll applicator 30, traveling in the same direction as the web 10 is moving at a relatively slower linear speed in the range of 5 to 30 per cent of the roll 4 and web 10 speed. Consequently, as the coating material 22 is applied to the circumferential surface 32 of the roll 30 by the enclosed coating applicator 20, the linear speed of the roll 30 will be insufficient to cause vortice or other turbulence typical in the pond of an enclosed coating applicator as would be the case if the coating material application were to a web or roll surface traveling at high speed.
- the gap space between the web 10 and the surface 32 of the roll 30 is such that only the coating material 22 engages the web 10.
- the enclosed coating applicator 20 also controls the thickness and thus the weight of the coating material 22 applied to the surface 16 of the web 10 by a metering action in applying coating material to the surface 32 of the roll 30. This metered amount may be controlled or adjusted by adjusting the position and thereby the pressure applied by the metering blade 42 of the metering mechanism 40. Increasing the pressure of the metering blade 42 reduces the weight and thickness of the coating material 22 and, conversely, reducing the metering blade pressure increases the coating material weight and thickness. Since the enclosed coating applicator 20 extends in the axial direction of the applicator roll 30 across the lateral surface width w of the web, the coating material thickness may be controlled on this entire surface.
- the coating apparatus 2 utilizes an enclosed coating applicator 50 of the jet type.
- the enclosed coating applicator 50 may be used rather than the applicator 20 as shown in Fig. 1.
- the components of the invention, other than the applicator 20, would remain the same as in Fig.
- the enclosed jet coating applicator 50 is well-known in the prior art and includes a casing or enclosure 52 and a coating applicator nozzle 54 extending from the enclosure to a position adjacent the roll applicator 30.
- the applicator nozzle 54 has a nozzle gap 48, an adjustable lip 56, lip adjusting screws 58, and a metering mechanism 60.
- the metering mechanism includes a metering lip 62 which also forms part of the nozzle 54 and a lip control 64.
- the adjustable lip 56 extends across the entire width of the applicator 50 and controls the basic coating thickness applied to the applicator roll by setting the opening size of the nozzle gap 48 across the applicator by manipulation of the screws 58.
- each lip control 64 sets the position of a metering lip 62 to control the thickness and weight of coating material applied to the roll applicator adjacent the particular lip control 64. This permits profiling of the coating material 22 applied to the roll applicator and thus also to the web 10.
- a pump 46 supplies coating material 22 through pipe 66 and passageway 68 to the nozzle 54 at a pressure above atmospheric pressure.
- the roll 4 and paper web 10 travel at a relatively high linear speed of, for example, in the range of 200 to 3000 meters per minute.
- the roll applicator 30 moves at a relatively slower linear speed in the range of 5 to 30 per cent of the roll 4 and web 10 speed.
- the low linear speed of the roll 30 will not create turbulence affecting the coating material which is sufficient to cause breakup of the coating material.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU92134/98A AU9213498A (en) | 1997-10-31 | 1998-09-01 | High speed coating apparatus and method |
CA002325906A CA2325906A1 (en) | 1997-10-31 | 1998-09-01 | High speed coating apparatus and method |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US96215697A | 1997-10-31 | 1997-10-31 | |
US08/962,156 | 1997-10-31 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999023308A1 true WO1999023308A1 (en) | 1999-05-14 |
Family
ID=25505490
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1998/018107 WO1999023308A1 (en) | 1997-10-31 | 1998-09-01 | High speed coating apparatus and method |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU9213498A (en) |
CA (1) | CA2325906A1 (en) |
WO (1) | WO1999023308A1 (en) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB191421892A (en) * | 1913-10-31 | Comet Pierre | Improvements in or relating to the Tinting or Colouring of Paper and other Materials. | |
US2329034A (en) * | 1941-01-15 | 1943-09-07 | Imp Paper & Color Corp | Apparatus for coating paper |
US2428113A (en) * | 1942-11-09 | 1947-09-30 | John R Ditmars | Machine for coating paper |
WO1991015306A1 (en) * | 1990-04-03 | 1991-10-17 | Btg Källe Inventing Ab | Process for two-faced coating of a travelling web |
-
1998
- 1998-09-01 CA CA002325906A patent/CA2325906A1/en not_active Abandoned
- 1998-09-01 WO PCT/US1998/018107 patent/WO1999023308A1/en active Application Filing
- 1998-09-01 AU AU92134/98A patent/AU9213498A/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB191421892A (en) * | 1913-10-31 | Comet Pierre | Improvements in or relating to the Tinting or Colouring of Paper and other Materials. | |
US2329034A (en) * | 1941-01-15 | 1943-09-07 | Imp Paper & Color Corp | Apparatus for coating paper |
US2428113A (en) * | 1942-11-09 | 1947-09-30 | John R Ditmars | Machine for coating paper |
WO1991015306A1 (en) * | 1990-04-03 | 1991-10-17 | Btg Källe Inventing Ab | Process for two-faced coating of a travelling web |
Also Published As
Publication number | Publication date |
---|---|
CA2325906A1 (en) | 1999-05-14 |
AU9213498A (en) | 1999-05-24 |
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