CA2116962A1 - Ultrasonically assisted coating apparatus and method - Google Patents
Ultrasonically assisted coating apparatus and methodInfo
- Publication number
- CA2116962A1 CA2116962A1 CA002116962A CA2116962A CA2116962A1 CA 2116962 A1 CA2116962 A1 CA 2116962A1 CA 002116962 A CA002116962 A CA 002116962A CA 2116962 A CA2116962 A CA 2116962A CA 2116962 A1 CA2116962 A1 CA 2116962A1
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- CA
- Canada
- Prior art keywords
- web
- coating material
- coating
- applying
- exciting
- 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.)
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C9/00—Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important
- B05C9/08—Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important for applying liquid or other fluent material and performing an auxiliary operation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C11/00—Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00
- B05C11/02—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface
- B05C11/023—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface
Landscapes
- Application Of Or Painting With Fluid Materials (AREA)
- Coating Apparatus (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
- Encapsulation Of And Coatings For Semiconductor Or Solid State Devices (AREA)
- Treatment Of Fiber Materials (AREA)
Abstract
An ultrasonically assisted coating apparatus (10', 26', 36', 44', 50', 60') and method for applying a smooth layer of coating material (18) on a surface of a moving web (16) are disclosed. A
coating material (18) is applied onto one web (16) surface. An ultrasonic energy generator (20, 22, 40) excites the line of initial contact between the coating material (18) and the web (16) at a uniform ultrasonic intensity selected in combination with the properties of the coating material (18). The coated web (16) has a thin, uniform crossweb thickness with low thickness variations.
coating material (18) is applied onto one web (16) surface. An ultrasonic energy generator (20, 22, 40) excites the line of initial contact between the coating material (18) and the web (16) at a uniform ultrasonic intensity selected in combination with the properties of the coating material (18). The coated web (16) has a thin, uniform crossweb thickness with low thickness variations.
Description
WO 93/07969 PCI /U~i92/07610 -l- 2116962 ULTRASONICALI.Y ASSISTED COATING APPARATUS AND MET~IOD
The present invention relates to an acoustically assisted coating apparatus and a method for applying one or more layers of a coating material - onto a moving web. More particularly, the present invention relates to using ultrasonic energy to improve the application of a smooth, uniform layer of coating material onto a moving web.
BACKGROUND ART
Ultrasonically created fluid effects have been noted in the literature since the early l900's.
Since the 1960's, the development of improved transducers for~generating ultrasonic energy increased activity in this~field. Ultrasonic phenomena which 20~ . relate to fluid processing or coating technologies include cavitation, viscous heating, increased shear, microturbulence,~;~and~acoustic streaming~ These phenomena generate effects that include enhanced wettability, micromixing, dispersion, emulsification, , 2~5~ deaeration, agglomeration, sep~ration of compo~ents, viscosity reduction, poIymer~chain disentanglement, high polymer degradation, and increased chemical reaction rates.~
::~
~ ~ Last et al , U.S. Patent No. 4,302,485, ~
:, ; 30 discloses using ultrasonic energy in an immersed ~ saturation system to excite a strip of fabric passing ;~ ~ through a bath of~liquid finishing agent. This causes cavitation in the bath and increases the microturbulence to thereby increase wicking. The :
:
WO93/07g69 PCT/US92/07610 21i'~962 -2-fabric is impregnated from both sides, and the liquid is not metered onto the fabric.
In U.S Patent No. 4,307,128 to Nagano et al., ultrasonic energy is used in a molten metal bath to locally lift a portion of the molten metal surface such that it contacts a moving surface of a substrate.
The coating is not metered. Absent ultrasonic energy, this apparatus is apparently inoperative.
U.S.~Patent No. 3,676,216 to Abitboul teaches applying ultrasonic energy to a previously ::
coated web to more uniformly and consistently distribute the coating over the web and to smooth irregularities in the coating. However, the ultrasonic energy is transmitted through the air to - ~ 15 excite the coated~web after the web is completely coated.
Japanese Patent No. 57-187071 discloses applying ultrasonic energy to the backside of a coated web. However, the ultrasonic source is too far from :` : ~ ~ :
20~ ~the~point of coating for the ultrasonic energy to affect the liquid~at the~first contact between the liquid~and the web~or at the la~st contact between the : ~ . , liq~uid and the coating equipment.
In Canadian Patent No. 869,959, a nozzle for 2S~ applying a liquid~coating from a hopper onto a moving web is ultrasonicàlly excited. A horn ultrasonically vibrates the nozzle to prevent the coating from sticking in and~clogging the nozzle. However, the ultrasonic vibrations only affect the coating before it is placed on~the web, and do not affect the process during the initial contact between the coating and the web or thereafter. Thus, the ultrasonic vibrations do not affect the un~iformity of the thickness of the coating as the coating is applied. The Canadian :
The present invention relates to an acoustically assisted coating apparatus and a method for applying one or more layers of a coating material - onto a moving web. More particularly, the present invention relates to using ultrasonic energy to improve the application of a smooth, uniform layer of coating material onto a moving web.
BACKGROUND ART
Ultrasonically created fluid effects have been noted in the literature since the early l900's.
Since the 1960's, the development of improved transducers for~generating ultrasonic energy increased activity in this~field. Ultrasonic phenomena which 20~ . relate to fluid processing or coating technologies include cavitation, viscous heating, increased shear, microturbulence,~;~and~acoustic streaming~ These phenomena generate effects that include enhanced wettability, micromixing, dispersion, emulsification, , 2~5~ deaeration, agglomeration, sep~ration of compo~ents, viscosity reduction, poIymer~chain disentanglement, high polymer degradation, and increased chemical reaction rates.~
::~
~ ~ Last et al , U.S. Patent No. 4,302,485, ~
:, ; 30 discloses using ultrasonic energy in an immersed ~ saturation system to excite a strip of fabric passing ;~ ~ through a bath of~liquid finishing agent. This causes cavitation in the bath and increases the microturbulence to thereby increase wicking. The :
:
WO93/07g69 PCT/US92/07610 21i'~962 -2-fabric is impregnated from both sides, and the liquid is not metered onto the fabric.
In U.S Patent No. 4,307,128 to Nagano et al., ultrasonic energy is used in a molten metal bath to locally lift a portion of the molten metal surface such that it contacts a moving surface of a substrate.
The coating is not metered. Absent ultrasonic energy, this apparatus is apparently inoperative.
U.S.~Patent No. 3,676,216 to Abitboul teaches applying ultrasonic energy to a previously ::
coated web to more uniformly and consistently distribute the coating over the web and to smooth irregularities in the coating. However, the ultrasonic energy is transmitted through the air to - ~ 15 excite the coated~web after the web is completely coated.
Japanese Patent No. 57-187071 discloses applying ultrasonic energy to the backside of a coated web. However, the ultrasonic source is too far from :` : ~ ~ :
20~ ~the~point of coating for the ultrasonic energy to affect the liquid~at the~first contact between the liquid~and the web~or at the la~st contact between the : ~ . , liq~uid and the coating equipment.
In Canadian Patent No. 869,959, a nozzle for 2S~ applying a liquid~coating from a hopper onto a moving web is ultrasonicàlly excited. A horn ultrasonically vibrates the nozzle to prevent the coating from sticking in and~clogging the nozzle. However, the ultrasonic vibrations only affect the coating before it is placed on~the web, and do not affect the process during the initial contact between the coating and the web or thereafter. Thus, the ultrasonic vibrations do not affect the un~iformity of the thickness of the coating as the coating is applied. The Canadian :
patent is representative of a body of art which 211 6 9 62 discloses applying ultrasonic energy to a nozzle during coating to improve flow through and from the nozzle. However, these apparatus are not practical for use in large scale production applications where wide coatinqs are being applied. In the formation of web rolls such as adhesive tapes, it is common to form the rolls in up to 150 cm (60 inch) widths. Rolls this-size could not be formed while achieving uniform ultrasonic excitation of sufficient intensity at the nozzle due to tbè~difficulty in exciting the necessary masses and lengths involved.
None of the known apparatus or systems disclose metering the coating onto only one side of l5~ the web and using acoustic energy to improve the charaateristics of an~applied coating before the coating of the~web~is complete.
DISCLOSURE OF INVENTION
~ The~present~invention overcomes these problems and uses~acoustic energy to assist the coating of a~smooth~continuous or discontinuous layer of a metered quant~ity of liquid aoating material having a substantially uniform crossweb thickness on , 25~ one surface of a~;moving web. The apparatus includes a device which applies a coating material onto at least a~portion of the~surface of the web. The device may be any type of coating system in which the coating can be applied onto~one side of the web, such as, for ::
example, extrusion, curtain, slot-fed knife, hopper, fluid bearing, notch bar, blade, and roll coaters. -~
A coating applicator meters and applies a controlled amount of coating material onto one surface of the web across the width of the web. An ultrasonic -~
~,.
energy source excites the line of initial contact between the coating material and the web preferably at a uniform acoustic intensity, amplitude, and frequency in the low end of the ultrasonic spectrum. Where a downweb structure is used as part of the die or as a separate structure to level or smooth the coating, the ultrasonic energy source can excite the line of final contact between the coating applicator device or downweb structure and the coated web. Additionally, lQ the ultrasonic energy can excite the area between the region of initial contact of the coating material and ~ the web and the~region of final contact between the ;~ coating applicator device or downweb structure and the coating material. The acoustic intensity is selected lS in combination with the properties of the coating material and the web to create a coated web having a substantia}ly uniform crossweb thickness.
When the coating material is applied through a die, the ultrasonic energy generator can apply ultrasonic energy to the coatin~ material-web interface through the die. Alternatively, ultrasonic energy is applied through the back surface of the web, through a backup~horn which replaces a conventional support. The~ultrasonic energy can also be transmitted through~the air or other coupling fluid.
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BRIEF DESCRIPTION OF DRAWTNGS
Figure l schematically illustrates contact extrusion. Figure lA shows contact extrusion without acoustic excitation and Figures lB, lC, lD, lE, lF, and IG show contact extrusion with various ways of applying acoustic energy.
Figure 2 schematically illustrates curtain coating. Figure 2A shows curtain coating without W~ 93/07g6g PCr/USg2/07610 -5- 211 6~ 6 acoustic excitation and Figures 2B, 2C, 2~, and 2E
show curtain coating with various ways of applying acoustic energy.
Figure 3 schematically illustrates slot-fed knife coating. Figure 3A shows slot-fed knife coating without acoustic excitation and Figures 3B, 3C, and 3D
show slot-fed knife coating with various ways of applying acoustic energy.
~igure 4 schematically illustrates slide coating. Figure 4A shows slide coating without acoustic excitation and Figure 4B shows slide coating with acoustic excitation.
Figure S schematically iliustrates roll coating. Figure~5A shows roll coating without acoustic excitation and Figure SB shows roll coating with acoustic excitation.
Figure~6~schematically illustrates non-contact extrusion~coating. Figure 6A shows extrusion coating without acoustic excitation and 20~ Figures 6B and 6C~show extrusion coating with acoustic excitation.
Figure~7A~is a graph of a cross web coating thickness profilè~without ultrasonics and Figure 7B is a graph of the~cross web coating thickness profile ~ coated with~ultrasonics.
Figure 8A is a graph comparing the average percentage coating thickness range variation for test runs with ultrasonics and for test runs without ultrasonics. ~ Figure 8B is a graph comparing the coating thickness standard deviation variation as a : ~ :
percentage for test runs with ultrasonics and for test runs without ultrasonics.
: .
wo9~/oi~9~63g~6æ -6- P~/US92/07610 DETAILED DESCRIPTION
The apparatus and coating method of the present invention apply acoustic energy to the interface between a web and a liquid coating material applied on the web. Although acoustic energy can be applied at various locations in all coating systems, improved coating is best achieved in systems which coat the web on one surface. With this system acoustic energy is used to improve coating thickness uniformity on the coated web, increase wettability (the ability of a liquid to replace a gas in contact with a substrate), reduce edge beads and streaks, reduce viscous drag, increase the coating gap between the coating equipment and the web, yield more stable eguipment operation and self-cleaning equipment, reduce the tendency for air entrainment, coat at higher speeds, and reduce the minimum possible coating thickneæs~ The increased coating uniformity reduces distortion, peaking and gapping, high spots, and 20 ~ telescoping of wound rolls of coated webs.
This invention is described with respect to applying smooth, continuous coatings. Nonetheless, these results also can be attained while applying smooth discontinuous coatings. For example, 25~ ultrasonic energy~ can be used with the coating of a web having a~ macrostructure such as voids which are ; filled with a coating but there is not continuity between the coating in adjacent voids. In this situation, the coating uniformity and enhanced wettability is maintained both within discrete coating regions and from region to region, with the regions separate from each other in both the downweb and crossweb directions.
W~93/07969 PCT/US92/07610 _7_ 21169~2 The web can be any material such as polyester, polypropylene, paper, or nonwoven materials. The improved wetting of the coating is particularly useful in rough textured or porous webs, regardless of whether the pore size is microscopic or macroscopic.
The web and the coating material are excited at a preferably uniform ultrasonic intensity across the width of the coated web. The intensity is selected in combination with the coating material properties to maximize crossweb coating thickness uniformity. Although the frequency and amplitude can be~varied w~ile~maintaining a uniform ultrasonic intensity, ultrasonic waves having uniform amplitude lS and frequency are preferred.
Acoustic waves are longitudinal waves caused -;
by periodic compression and rarefaction of the medium through which they travel. Thése waves also can generate other acoustic waves such as surface 20 ~ transverse acoustic waves. Acoustic waves contain both kinetic energy~of motion and potential energy of compressed matter. ~The acoustic energy density, E, is a measure~of the energy per volu~e in an longitudinal acoustic wave and is represented by:
25~ ~
E = ~2 pof2Xo where pO is;the~density of the medium when no acoustic waves travel throuqh it, f is the frequency of the , ~ :
~ 30 acoustic wave, and xO is the peak-to-peak amplitude.
;~ Where differences in acoustic energy density occur`, forces exist which can manipulate coating liquids.
The ultrasonic energy intensity, I, is a function of the amplitude and frequency of the waves wo23~o~ 6 2 PCT/U~92/07610 and the properties of the medium and is represented by:
I = c ~2 pof2Xo where c is the speed of the acoustic waves in the medium.
When an acoustic wave encounters a boundary between two media~, part of the wave is transmitted through and the~rest is reflected from the boundary.
The proportion of transmission to reflectance depends on how similar~the~acoustic impedances of the two media are. The~characteristic acoustic impedance, R, is as follows:
::
R = poc~
If the impedances~of;two media are similar, most of the wave will be~`transmitted. If the impedances ;~
20 ~ di~ffer~widely, most~of the wave will be reflected.
However,~when;a thin layer is sandwiched between two materials~with similar~acoustic impedances, the thin ;~
layer tr~ansmits~the~acoustic waves e~en though its impèdance differs~from that of the other materials.
25~ The~application of ultrasonic energy provides the~desired results when used with any type ` of coaters in which the coating is metered or measured and applied to one~surface of the web. Extrusion . ~
coaters, both-oontact and non-contact, are illustrated in Figures l~and 6, respectively. Curtain coaters are ; illustrated in Figure 2. Knife coaters include slot-fed knife,~hopper, fluid bearing, notch bar, and blade coaters, and will be discussed with reference to a slot-fed ~nife~coater as illustrated in Figure 3.
:
W~g3/07969 PCT/US92/07610 g 211 ~962 Slide coaters are illustrated in Figure 4. Roll coaters include gravure and kiss coaters and are generically represented in Figure 5. Although other types of coaters are also enhanced by the application of acoustic energy, the systems described below are representative. The operation of the invention is generalIy similar with all of these coating methods.
Re~erring to Figure 1, a contact extrusion coating system is shown. In Figure lA, no ultrasonic excitation is provided.~ A coating system 10, includes ., an extrusion die 12 located adjacent a backup roller 14. A web 16 of material to be coated travels from left to right in-the figure. Coating material 18 is extruded onto and across the web 16 as shown. The coating~material~;18 may be applied across the entire :: : . .
width of~the web 16 or across any fraction of the ;width in the known~manner.
In Figures lB, lC, lD, lE, lF, and lG, ultrasonic energy~is~applied to the system lO such ; that the~ energy acts on the web 16 and coating 18 in the region of initial contact between the web 16 and coating 18. The details of this ultrasonic excitation are~described below. In the coating system lO' of Figure lB, a resonant sonotrode or ultrasonic horn 20 25 ~ replaces the backup roller 14. The ultrasonic horn 20 ; is a specially~designed horn which can vibrate at selected frequencies or amplitudes of vibration. The ~; ultrasonic energy is applied directly to the web 16 and excites the~web 16 and coating 18 at the location 3Q of initial contac between the coating 18 and the web -~ 16.
In Figure lC, both an ultrasonic horn 20 and a backup roller 14 are used in the coating system 10'.
The backup roller 14 is located opposite the extrusion .
WO g3/07~69 PC~/USg2/~7610 2.~ ~;962 -lo-die 12, and the ultrasonic horn 20 is located downweb from this location. The ultrasonic energy is applied directly to the coated web 16 and the energy travels through the web 16 and coating 18 to excite the line of initial contact between the coating 18 and the web 16 Although the horn 20 is shown downweb of the die 12, it also could be located upweb of the die 12.
Additionally, although the ultrasonic energy is not applied directly to the line of initial contact between the coating 18 and the web 16, the energy is applied with a sufficient intensity such that when it reaches the initial contact line it has sufficient energy.
The coating system 10' of Figure lD includes similar components to the known system 10 of Figure lA. The web 16~ passes around a backup roller 14 and the coating material 18 is extruded onto and across the desired width of the web 16. An extrusion die 22 applies the coating material 18 onto the web 16.
20 ~However, in Figure lD, the die 22 is ultrasonically ; ~ excited to excite the coating 18 within the die 22 and the excited coating 18 is extruded onto the web 16.
The ultrasonic die 22 is a specially designed die ~` connected to an~ultrasonic energy generator, either in . ~
25~ a~sinqle housing~as shown, or by externally securing the two together as with a mounting bracket. The ultrasonic energy travels through the co~ting 18 to excite the region of initial contact between the coating 18 and~the web 16.
Referring to Figure 2, a curtain coating system is shown.~ In the coatin~ system 26 of Figure 2A, no ultrasonic excitation is provided. The curtain coating die 28 is spaced above the bac~up roller 14.
The web 16 travels from left to right in the figure.
-11- 21169~
The coating material 18 is extruded from the die 28 and falls in a curtain onto the web l6 across the desired width of the web 16.
In Figure 2B, ultrasonic energy is applied S to the coating system 26' such that the energy acts on the web 16 and coating 18 in the region of initial contact between the web 16 and coating 18. The ultrasonic horn 20 replaces the backup roller 14. The . .
ultrasonic energy is applied directly to the web 16 ~' and excites the web 16 and coating 18 at the location of initial contact between the coating 18 and the web ' :~ 16. In Figurè 2C, both an ultrasonic horn 20 and a '~
backup roller 14 are used. The ultrasonic energy is applied directly to the coated web 16 and the energy ~: 15 travels upweb through the web 16 and coating 18 to :~ excite the line of initial contact between the coating 18~and the web I6. Moreover, when the curtain length , is short, an ultrasonic die (not shown) can be used in a manner similar to, the system 10' of Figure lD.
" 20 Additionally, a downweb structure such as a rigid leveling bar 30 shown in Figure 2D, or a flexible leveling pad 32 shown in Figure 2E may be used to smooth or level the coating material 18 after it is applied to~improve the thickness uniformity.
25: When a downstream element such as the leveling bar 30 or leveling pad:32 is used as part of the coat'ing system 26', application of ultrasonic energy can be beneficially applied in the region of final contact between the-coated web 16 and the downweb leveling : 30 structure. Thus, the ultrasonic energy need not reach the region of initial contact between the web 16 and the coating 18~as~long as it reaches the region of final contact between the coated web 16 and the leveling bar 30 or leveling pad 32. The web beneath 9 62 -12- PCT/USg2/07610 the leveling bar 30 and the leveling pad 32 can be supported (as shown) or unsupported. These devices can be directly ultrasonically excited. An ultrasonically excited unsupported structure could also be used to meter the fluid.
Referring to Figure 3, a slot-fed knife die coating system 36 IS shown. In Figure 3A, no ultrasonic excitation is provided. The coating system 36 includes a slo~ ~éd knife die 38 located adjacent to the backup r~ller 14. The web 16 of material to be coated travels from left to right in the figure, and the coating material 18 is deposited onto the web 16 across the desired web width as shown.
In Figures 3B, 3C, and 3D, ultrasonic energy 15~ is applied to the system 36' such that the energy acts on the web 16 and coating 18 in the region of initial contact between~the web 16 and coating 18. In Figure 3B, the ultrasonic horn 20 replaces the backup roller 14. The ultrasonic energy is applied directly to the web 16 and excites the web 16 and coating 18 at the location of~initial contact between the coating 18 and the web 16, as well~as the coating 18 between the die 38 and the horn~2~0. In Figure 3C, both an ultrasonic horn 20 and a~backup roller 14 are used. The ultrasonic energy~is applied directly to the coated web 16 and the energy travels through the web 16 and coating 18 to excite the line of initial contact between the coating 18 and the web 16. In Figure 3D, the knife die is ultrasonicalIy excited and is shown as knife die 40. The coating 18 i5 excited while still within the knife die 40 and the energy travels through the coating 18 to the region of initial contact between the coating 18 and the web 16.
W093/07~9 PCT/USg2/07610 Additionally, the ultrasonic energy can ~-excite the area between the region of initial contact of the coating material and the web and the region of final contact between the coating applicator device or downweb structure and the coating material. This applies to all discussed coating methods when downweb structures are used.
Referring to Figure 4, a slide coating .
system 44 is shown. In Figure 4A, no ultrasonic excitation is provided. The coating system 44 is a , slide die 46, and~is located adjacent the backup ; roller 14. The'web~16 of material to be coated ~' travels from~left to~right in the figure and the ' coating material 18 is coated onto the web 16 as shown. ~The coating is applied across the desired width of the web 16.
In Figure 4B, ultrasonic energy is applied to the~system 44'~suc~ that the energy acts on the web 16,and~coating~18 in the region of initial contact 2~0~ between the web~16~and coating 18. The ultrasonic horn 20~replaces~the~backup roller 14 and the ultrasonic energy~is applied directly to the web 16 and excites the web 16 and coating 18 at the location of initial contact~between the coating 18 and the web ZS ~16. Moreover,~ an~ultrasonic slide die (not shown) in which the coating, 18 is excited while still within the slide~die and~the~energy travels through the coating ~; 18 to the region of initial contact between the coating 18 and the~web~l6 can be used.
Referring to Figure 5, a roll coating system : : : ~
,~ ~ 50 is shown. In~Figurë 5A, no ultrasonic excitation is provided. The~coating system 50 includes a pan 52 ' containing liqu~id coating material 18 and a roll 54 mounted for rotation within the pan 52. The backup :
W093/07969 PCT/USg2/07610 ~1 lG~2 -14-roller 14 is located adjacent the roll 54. The web 16 of material to be coated travels from left to right in the figure. The coating material 18 is applied to the web 16 across the desired width and a smoother or doctor blade 56 may be used to wipe off excess coating 18 and level or smooth the coating 18 on the web 16.
In Figure 5B, ultrasonic energy is applied to the system 5~' such that the energy acts on the web 16 and coating 18 in the region of initial contact between the web 16 and coating 18. This is accomplished by replacing the backup roller 14 with an : ultrasonic horn 20. The ultrasonic energy is applied directly to the~web 16 and excites the web 16 and coating 18 at the location of initial contact between ~ 15 ~ the coating lg and the web 16. Alternatively, when a :: ~dootor blade 56~is used as part of the coating :: applicator device lO to level or smooth the coating 18 on the web 16, application of ultrasonic energy can be beneficially applied:in the region of final contact 20:~ between the coated web 16 and the downweb doctor blade. Thus, when;the doctor blade is used, the ultrasonic~energy need not reach the region of initial contact:between~the:web 16 and the coating 18 as long as it reaches the region of final contact between the 25~ ~coated web 16 and~;the doctor blade. Ultrasonic energy also performs:well with other coating systems including those~with a plurality of rolls.
: Figures 6A, 6B, and 6C correspond to Figures : : lA, lB, and lC, respectively, and illustrate non-contact extrusion coating systems 60, 60'.
~: : In one~arrangement for all of the coating configurations,~the ultrasonic source is located at the line of initial contact between the coating material and the web. Preferably, the ultrasonic W~93/07~6g PCT/~S~2/07610 -15- ~1 1 G9 ~2 energy is applied at the backside of the web through an ultrasonic horn used in place of a backup roll or other support. However, the ultrasonic source can be located remotely from the initial contact line to S apply energy to the coated or uncoated web as long as sufficient ultrasonic energy reaches the line of initial contact. The maximum distance is about 15 cm although the best results have been found to occur within 8 cm. Alternatively, as discussed with respect to Figure 2, the ultrasonic energy can be applied within 15 cm of the location of any downweb leveling or-smoothing structure. Also, the ultrasonic energy can excite the area between the region of initial contact of the coating material and the web and the lS~ region of final contact between the coating applicator device or downweb structure and the coating material.
The ultrasonic energy can be applied at any one or a combination of these areas.
Regardless of the location of the u}trasonic energy source, the ultrasonic energy adds energy to the coating liquid. As the acoustic energy intensity increases, the coating quality and processability, including the thickness uniformity, improves until an optimum acoustic intensity level is reached. Acoustic energy preferably is applied near this optimum level which is at intensity levels between 0.1 W/cm2 and 40 W/cm2, depending on the kind of coater and the type of material being coated. However, the application of ultrasonic energy can create web vibrations such as surface acoustic waves which apply energy to the coating. Depending on the magnitude of the vibration, this can improve or degrade the coating quality. Care must be taken to avoid adverse affects such as lower W093/07969 PCT/USg2/07610 2~ GQ62 -16-frequency standing waves which yield coating nonuniformity.
The application of ultrasonic energy through a backup horn that generally replaces a backup roller S is the preferred arrangement in all coating configurations. The ultrasonic energy can be applied to the web by direct contact or through any medium which transmits a~sufficient amount of energy such as a coupli:ng fluid. The working surface of the horn itself, and also the web in contact with the horn, is at or near a pressure node in the acoustic standing wave. As the ultrasonic energy is transmitted and , :
reflected by the~web and the coating material, the combined waves~pull coating material toward the horn pressure node and toward the web. This improves drawdown in extrusion coating and provides a more stable liquid contact line in both extrusion and curtain coating.~The coating material is urged to the web and reduces~the~tendency for air entrainment 20 ~ between the~coating and the web. Other desirable effects that improve wettability include phenomena such~as ultrasonic viscosity reduction and contact line and~bulk fluid~dynamics with the associated fluid momentum contributions. Furthermore, because the horn 2~5 is a rigidly mounted, nonrotating, low friction surface, backup roll runout and the associated downweb variations are~eliminated. If desired, a carrier web could be used;to shield the moving coated web from the -~ stationary ultrasonic horn.
3~ I~f the~region of initial contact between the coating material and web is confined by another structure, as with the slot-fed knife system of Figures 3B and 3D, additional effects may occur.
Because the coating material forms a thin layer :, W093/0796g -17- 7f f 6 9 6 2 between two acoustically-matched materials, the transmission of acoustic energy is greatly enhanced.
The acoustic energy density in the coating material between the die and the web is much greater than that outside this region. Moreover, if a low coating weight or void streak occurs in the coating area, the acoustic energy density in this area is lower and an increased fluid crossflow occurs which fills in the streak. The increased energy density of the fluid in the coating area increases the crossweb flow, reduces streaks, reduces the tendency for air entrainment, and results in better~crossweb uniformity and a flow configuration~which is more resistant to external disturbances. Additionally, the system can operate 15~ with larger gaps between the die and the web. This permits operating with larger process tolerances as the die position is not as critical-as when ultrasonic ;energy is not used. The use of larger coating gaps reduces~web tear-out problems. Also, machining 20 ~ variations on the;die faces become a smaller percentage of the~`total coating qap and their adverse ; effect on coating uniformity is reduced.
:
The preferred frequency of vibration for the acousti~ enerqy ~is~at the low end of the ultrasonic ~25 ~ spectrum at 20,000 Hz. However, because the benefits of ultrasonically-assisted coating are not highly dependent on frequency, a broad range of high and low frequencies is functional. Although lower frequencies are audible and~present noise control problems, they can be used when higher amplitudes are required as with more viscous liquids or for scale-up of larger systems. Higher frequency ultrasonic systems present scale-up problems because they are smaller due to the shorter wavelengths that accompany higher frequencies.
WOg3/07g~9 PCT/US92/07610 21 i ~ ~ -18-However, high frequency systems may be preferred for lower viscosity (less than 500 cps) liquids as they generate fewer low frequency resonances.
Peak-to-peak amplitudes of ultrasonic vibration between 0.002 mm and 0.20 mm have been tested in ultrasonically-assisted coating. The higher amplitudes are more useful for highly viscous liquids or thin layers whereas lower viscosity liquids or thick layers require lower amplitudes. For example, in a slot-fed knife system with a S,000 cps solvent-based rubber coating, a peak-to-peak amplitude of 0.03 mm at 20,000 Hz is sufficient to observe the desired improvements in coating quality. If the amplitude is too large, coating uniformity can be disrupted by~localized nonuniformities such as rippling ef~fects.
The~angle~of input of the ultrasonic waves preferably is perpendicular to the direction of web travel, as shown ~in Figures ~B and lC. However, while 20~ this orientation~is preferred, the angle of input can range from perpendicular to parallel to the plane of ;the web l6. Figures lE and lF show systems similar to Figures lB and lC~in which the ultrasonic energy is transmitted through an ultrasonic horn 20 and an 25~ ultrasonic die~2~2,~respectively. In these embodiments, the horn 20 and the die 22 transmit the ;~ ultrasonic enerqy at an angle between 0 and 90. ln ` Figure lG, the~ultrasonic horn 20 transmits the -~
uItrasonic energy in a direction parallel to the plane ~ .
of the web 16 such that the amplitude of vibration of the ultrasonic energy lies in the direction of web 16 tra~el. ~
If~ultrasonic~energy is applied through the `-coating die (as in Figures lD and 3D) it also effects .
:
W~93/07969 PCT/US92/07610 the flow of coating material in the die. It h1sl ~ a~2 found that in some instances when the pumping force is held constant, the flow rate through the die is doubled when ultrasonic energy is applied parallel to the liquid motion and the flow rate is improved by a factor of five when it is applied in the perpendicular direction. In addition, ultrasonic excitation of the die increases the temperature of the coating material which improves the natural flow of coating from the die. Also, debris stuck in die crevices can be coaxed out of the die by ultrasonic excitation, thus ; eliminating the presence of streaks in the coated web due to trapped debris. The die is preferably excited as a standing wave. Alternatively, the ultrasonic vibrations can be appIied as a traveling wave propagating through the die, either with or without the use of a coupling material.
Many series of experiments with various fluids have been run. In one experiment, a 30 cm ~12 ~`20 in) wide knife die with an ultrasonic backup horn was -used. A rubber-based adhesive was coated at a web speed of 7.62 mlmin (25 ft/min) at 0.0635 mm (0.0025 ; in) thick. The~ultrasonic amplitude was about 0.0305 ~mm (0.0012 in) peak-to-peak. One area in the die was .
25 intentionally plugged for about 1 mm ~0.04 in) to ~-~ simulate a clogged die and demonstrate the ability of ; the ultrasonics to compensate with sufficient crossflow in the coating nip to mask streaks. Cross web coating thickness profiles were taken and are 30 illustrated in Figure 7. The coating width on the web -is shown along the x-axis and the coating thickness is shown along the y-axis. Figure 7A shows coating without ultrasonics. A streak at area A was caused by the plug in the~die orifice and a dip at area B was a W0~3~07969~ PCT/US92/07610 naturally occurring thin coating area in the web.
When the ultrasonics was turned on, the area A filled in to within 92% of the overall coating thickness and the area B dip was essentially eliminated, as shown in S Figure 7B.
Pilot plant data also was obtained. A run of 24,689 m (81,000 ft) of 61 cm ~24 in) wide rubber-based adhesive tape was made at 15.24 to 30.48 m/min (50 to 100 ft/min) using a slot fed knife die with an ultrasonic backup horn. The ultrasonic amplitude was varied between 0.015 and 0~025 mm (0.0006 and 0.001 ~inj peak-to-peak. The coating was 0.030 mm (0.0012~in)~ thick and crossweb profiles were measured. Ten consecutive scans of 230 data points each were taken noting the range of the coating : : : ~ :
thickness and~the standard deviation of the last scan, and the average range and standard deviation of all ten scans. (The~range is the minimum to maximum crossweb coating~thickness.) The~ten scan ~roups were 20 ~ ~performed 17 times with ultrasonics and 9 times without ultrasonics.
An indicatîon of transient coating thickness variation can be~determined by considering how much the range~of~a single scan varies from the average ;25 ~ range of severa~ scans before it. The coating range variations that~occur with time therefore can be indicated by subtracting the average range of the ten scans from the tenth scan of a group of ten scans, taking the absolute value, and dividing by the average range. This is~performed for all of the groups of ten scans, then averaged. Figure 8A compares the average range variation as a percentage for the scan groups with ultrasonics with the scan groups without ultrasonics. Ultrasonics reduces the percent :
.. . .. ... . . ... . ~ .. . , . ~ .. .. .. ~ . ... . .
W~93/07969 PCT/US92/07610 -21- 211 69~2 variation from 47% to 15%, a three-fold reduction.
Figure 8B compares the standard deviation variations of the runs with and without ultrasonics. The standard deviation variation percentages were reduced from 25~ to 10% when ultrasonics was used. These figures show the improved consistency of the overall crossweb caliper profile as a function of run time.
- Once a desired coating profile has been established, the profile varies less with time when ultrasonics is present than without ultrasonics.
Various~changes and modifications may be ~-effected therein~by one skilled in the art without departing from the scope or spirit of the invention.
~ For example, instead of using a sonotrode as the 15 ultrasonic energy source, eccentric cams or white ~-noise genera~tors~can be used to improve coatings.
Additionally, acoustic energy can be applied to both sides~of the web. ~
:
:
:
.
: ~ .
f ~ .
None of the known apparatus or systems disclose metering the coating onto only one side of l5~ the web and using acoustic energy to improve the charaateristics of an~applied coating before the coating of the~web~is complete.
DISCLOSURE OF INVENTION
~ The~present~invention overcomes these problems and uses~acoustic energy to assist the coating of a~smooth~continuous or discontinuous layer of a metered quant~ity of liquid aoating material having a substantially uniform crossweb thickness on , 25~ one surface of a~;moving web. The apparatus includes a device which applies a coating material onto at least a~portion of the~surface of the web. The device may be any type of coating system in which the coating can be applied onto~one side of the web, such as, for ::
example, extrusion, curtain, slot-fed knife, hopper, fluid bearing, notch bar, blade, and roll coaters. -~
A coating applicator meters and applies a controlled amount of coating material onto one surface of the web across the width of the web. An ultrasonic -~
~,.
energy source excites the line of initial contact between the coating material and the web preferably at a uniform acoustic intensity, amplitude, and frequency in the low end of the ultrasonic spectrum. Where a downweb structure is used as part of the die or as a separate structure to level or smooth the coating, the ultrasonic energy source can excite the line of final contact between the coating applicator device or downweb structure and the coated web. Additionally, lQ the ultrasonic energy can excite the area between the region of initial contact of the coating material and ~ the web and the~region of final contact between the ;~ coating applicator device or downweb structure and the coating material. The acoustic intensity is selected lS in combination with the properties of the coating material and the web to create a coated web having a substantia}ly uniform crossweb thickness.
When the coating material is applied through a die, the ultrasonic energy generator can apply ultrasonic energy to the coatin~ material-web interface through the die. Alternatively, ultrasonic energy is applied through the back surface of the web, through a backup~horn which replaces a conventional support. The~ultrasonic energy can also be transmitted through~the air or other coupling fluid.
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BRIEF DESCRIPTION OF DRAWTNGS
Figure l schematically illustrates contact extrusion. Figure lA shows contact extrusion without acoustic excitation and Figures lB, lC, lD, lE, lF, and IG show contact extrusion with various ways of applying acoustic energy.
Figure 2 schematically illustrates curtain coating. Figure 2A shows curtain coating without W~ 93/07g6g PCr/USg2/07610 -5- 211 6~ 6 acoustic excitation and Figures 2B, 2C, 2~, and 2E
show curtain coating with various ways of applying acoustic energy.
Figure 3 schematically illustrates slot-fed knife coating. Figure 3A shows slot-fed knife coating without acoustic excitation and Figures 3B, 3C, and 3D
show slot-fed knife coating with various ways of applying acoustic energy.
~igure 4 schematically illustrates slide coating. Figure 4A shows slide coating without acoustic excitation and Figure 4B shows slide coating with acoustic excitation.
Figure S schematically iliustrates roll coating. Figure~5A shows roll coating without acoustic excitation and Figure SB shows roll coating with acoustic excitation.
Figure~6~schematically illustrates non-contact extrusion~coating. Figure 6A shows extrusion coating without acoustic excitation and 20~ Figures 6B and 6C~show extrusion coating with acoustic excitation.
Figure~7A~is a graph of a cross web coating thickness profilè~without ultrasonics and Figure 7B is a graph of the~cross web coating thickness profile ~ coated with~ultrasonics.
Figure 8A is a graph comparing the average percentage coating thickness range variation for test runs with ultrasonics and for test runs without ultrasonics. ~ Figure 8B is a graph comparing the coating thickness standard deviation variation as a : ~ :
percentage for test runs with ultrasonics and for test runs without ultrasonics.
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wo9~/oi~9~63g~6æ -6- P~/US92/07610 DETAILED DESCRIPTION
The apparatus and coating method of the present invention apply acoustic energy to the interface between a web and a liquid coating material applied on the web. Although acoustic energy can be applied at various locations in all coating systems, improved coating is best achieved in systems which coat the web on one surface. With this system acoustic energy is used to improve coating thickness uniformity on the coated web, increase wettability (the ability of a liquid to replace a gas in contact with a substrate), reduce edge beads and streaks, reduce viscous drag, increase the coating gap between the coating equipment and the web, yield more stable eguipment operation and self-cleaning equipment, reduce the tendency for air entrainment, coat at higher speeds, and reduce the minimum possible coating thickneæs~ The increased coating uniformity reduces distortion, peaking and gapping, high spots, and 20 ~ telescoping of wound rolls of coated webs.
This invention is described with respect to applying smooth, continuous coatings. Nonetheless, these results also can be attained while applying smooth discontinuous coatings. For example, 25~ ultrasonic energy~ can be used with the coating of a web having a~ macrostructure such as voids which are ; filled with a coating but there is not continuity between the coating in adjacent voids. In this situation, the coating uniformity and enhanced wettability is maintained both within discrete coating regions and from region to region, with the regions separate from each other in both the downweb and crossweb directions.
W~93/07969 PCT/US92/07610 _7_ 21169~2 The web can be any material such as polyester, polypropylene, paper, or nonwoven materials. The improved wetting of the coating is particularly useful in rough textured or porous webs, regardless of whether the pore size is microscopic or macroscopic.
The web and the coating material are excited at a preferably uniform ultrasonic intensity across the width of the coated web. The intensity is selected in combination with the coating material properties to maximize crossweb coating thickness uniformity. Although the frequency and amplitude can be~varied w~ile~maintaining a uniform ultrasonic intensity, ultrasonic waves having uniform amplitude lS and frequency are preferred.
Acoustic waves are longitudinal waves caused -;
by periodic compression and rarefaction of the medium through which they travel. Thése waves also can generate other acoustic waves such as surface 20 ~ transverse acoustic waves. Acoustic waves contain both kinetic energy~of motion and potential energy of compressed matter. ~The acoustic energy density, E, is a measure~of the energy per volu~e in an longitudinal acoustic wave and is represented by:
25~ ~
E = ~2 pof2Xo where pO is;the~density of the medium when no acoustic waves travel throuqh it, f is the frequency of the , ~ :
~ 30 acoustic wave, and xO is the peak-to-peak amplitude.
;~ Where differences in acoustic energy density occur`, forces exist which can manipulate coating liquids.
The ultrasonic energy intensity, I, is a function of the amplitude and frequency of the waves wo23~o~ 6 2 PCT/U~92/07610 and the properties of the medium and is represented by:
I = c ~2 pof2Xo where c is the speed of the acoustic waves in the medium.
When an acoustic wave encounters a boundary between two media~, part of the wave is transmitted through and the~rest is reflected from the boundary.
The proportion of transmission to reflectance depends on how similar~the~acoustic impedances of the two media are. The~characteristic acoustic impedance, R, is as follows:
::
R = poc~
If the impedances~of;two media are similar, most of the wave will be~`transmitted. If the impedances ;~
20 ~ di~ffer~widely, most~of the wave will be reflected.
However,~when;a thin layer is sandwiched between two materials~with similar~acoustic impedances, the thin ;~
layer tr~ansmits~the~acoustic waves e~en though its impèdance differs~from that of the other materials.
25~ The~application of ultrasonic energy provides the~desired results when used with any type ` of coaters in which the coating is metered or measured and applied to one~surface of the web. Extrusion . ~
coaters, both-oontact and non-contact, are illustrated in Figures l~and 6, respectively. Curtain coaters are ; illustrated in Figure 2. Knife coaters include slot-fed knife,~hopper, fluid bearing, notch bar, and blade coaters, and will be discussed with reference to a slot-fed ~nife~coater as illustrated in Figure 3.
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W~g3/07969 PCT/US92/07610 g 211 ~962 Slide coaters are illustrated in Figure 4. Roll coaters include gravure and kiss coaters and are generically represented in Figure 5. Although other types of coaters are also enhanced by the application of acoustic energy, the systems described below are representative. The operation of the invention is generalIy similar with all of these coating methods.
Re~erring to Figure 1, a contact extrusion coating system is shown. In Figure lA, no ultrasonic excitation is provided.~ A coating system 10, includes ., an extrusion die 12 located adjacent a backup roller 14. A web 16 of material to be coated travels from left to right in-the figure. Coating material 18 is extruded onto and across the web 16 as shown. The coating~material~;18 may be applied across the entire :: : . .
width of~the web 16 or across any fraction of the ;width in the known~manner.
In Figures lB, lC, lD, lE, lF, and lG, ultrasonic energy~is~applied to the system lO such ; that the~ energy acts on the web 16 and coating 18 in the region of initial contact between the web 16 and coating 18. The details of this ultrasonic excitation are~described below. In the coating system lO' of Figure lB, a resonant sonotrode or ultrasonic horn 20 25 ~ replaces the backup roller 14. The ultrasonic horn 20 ; is a specially~designed horn which can vibrate at selected frequencies or amplitudes of vibration. The ~; ultrasonic energy is applied directly to the web 16 and excites the~web 16 and coating 18 at the location 3Q of initial contac between the coating 18 and the web -~ 16.
In Figure lC, both an ultrasonic horn 20 and a backup roller 14 are used in the coating system 10'.
The backup roller 14 is located opposite the extrusion .
WO g3/07~69 PC~/USg2/~7610 2.~ ~;962 -lo-die 12, and the ultrasonic horn 20 is located downweb from this location. The ultrasonic energy is applied directly to the coated web 16 and the energy travels through the web 16 and coating 18 to excite the line of initial contact between the coating 18 and the web 16 Although the horn 20 is shown downweb of the die 12, it also could be located upweb of the die 12.
Additionally, although the ultrasonic energy is not applied directly to the line of initial contact between the coating 18 and the web 16, the energy is applied with a sufficient intensity such that when it reaches the initial contact line it has sufficient energy.
The coating system 10' of Figure lD includes similar components to the known system 10 of Figure lA. The web 16~ passes around a backup roller 14 and the coating material 18 is extruded onto and across the desired width of the web 16. An extrusion die 22 applies the coating material 18 onto the web 16.
20 ~However, in Figure lD, the die 22 is ultrasonically ; ~ excited to excite the coating 18 within the die 22 and the excited coating 18 is extruded onto the web 16.
The ultrasonic die 22 is a specially designed die ~` connected to an~ultrasonic energy generator, either in . ~
25~ a~sinqle housing~as shown, or by externally securing the two together as with a mounting bracket. The ultrasonic energy travels through the co~ting 18 to excite the region of initial contact between the coating 18 and~the web 16.
Referring to Figure 2, a curtain coating system is shown.~ In the coatin~ system 26 of Figure 2A, no ultrasonic excitation is provided. The curtain coating die 28 is spaced above the bac~up roller 14.
The web 16 travels from left to right in the figure.
-11- 21169~
The coating material 18 is extruded from the die 28 and falls in a curtain onto the web l6 across the desired width of the web 16.
In Figure 2B, ultrasonic energy is applied S to the coating system 26' such that the energy acts on the web 16 and coating 18 in the region of initial contact between the web 16 and coating 18. The ultrasonic horn 20 replaces the backup roller 14. The . .
ultrasonic energy is applied directly to the web 16 ~' and excites the web 16 and coating 18 at the location of initial contact between the coating 18 and the web ' :~ 16. In Figurè 2C, both an ultrasonic horn 20 and a '~
backup roller 14 are used. The ultrasonic energy is applied directly to the coated web 16 and the energy ~: 15 travels upweb through the web 16 and coating 18 to :~ excite the line of initial contact between the coating 18~and the web I6. Moreover, when the curtain length , is short, an ultrasonic die (not shown) can be used in a manner similar to, the system 10' of Figure lD.
" 20 Additionally, a downweb structure such as a rigid leveling bar 30 shown in Figure 2D, or a flexible leveling pad 32 shown in Figure 2E may be used to smooth or level the coating material 18 after it is applied to~improve the thickness uniformity.
25: When a downstream element such as the leveling bar 30 or leveling pad:32 is used as part of the coat'ing system 26', application of ultrasonic energy can be beneficially applied in the region of final contact between the-coated web 16 and the downweb leveling : 30 structure. Thus, the ultrasonic energy need not reach the region of initial contact between the web 16 and the coating 18~as~long as it reaches the region of final contact between the coated web 16 and the leveling bar 30 or leveling pad 32. The web beneath 9 62 -12- PCT/USg2/07610 the leveling bar 30 and the leveling pad 32 can be supported (as shown) or unsupported. These devices can be directly ultrasonically excited. An ultrasonically excited unsupported structure could also be used to meter the fluid.
Referring to Figure 3, a slot-fed knife die coating system 36 IS shown. In Figure 3A, no ultrasonic excitation is provided. The coating system 36 includes a slo~ ~éd knife die 38 located adjacent to the backup r~ller 14. The web 16 of material to be coated travels from left to right in the figure, and the coating material 18 is deposited onto the web 16 across the desired web width as shown.
In Figures 3B, 3C, and 3D, ultrasonic energy 15~ is applied to the system 36' such that the energy acts on the web 16 and coating 18 in the region of initial contact between~the web 16 and coating 18. In Figure 3B, the ultrasonic horn 20 replaces the backup roller 14. The ultrasonic energy is applied directly to the web 16 and excites the web 16 and coating 18 at the location of~initial contact between the coating 18 and the web 16, as well~as the coating 18 between the die 38 and the horn~2~0. In Figure 3C, both an ultrasonic horn 20 and a~backup roller 14 are used. The ultrasonic energy~is applied directly to the coated web 16 and the energy travels through the web 16 and coating 18 to excite the line of initial contact between the coating 18 and the web 16. In Figure 3D, the knife die is ultrasonicalIy excited and is shown as knife die 40. The coating 18 i5 excited while still within the knife die 40 and the energy travels through the coating 18 to the region of initial contact between the coating 18 and the web 16.
W093/07~9 PCT/USg2/07610 Additionally, the ultrasonic energy can ~-excite the area between the region of initial contact of the coating material and the web and the region of final contact between the coating applicator device or downweb structure and the coating material. This applies to all discussed coating methods when downweb structures are used.
Referring to Figure 4, a slide coating .
system 44 is shown. In Figure 4A, no ultrasonic excitation is provided. The coating system 44 is a , slide die 46, and~is located adjacent the backup ; roller 14. The'web~16 of material to be coated ~' travels from~left to~right in the figure and the ' coating material 18 is coated onto the web 16 as shown. ~The coating is applied across the desired width of the web 16.
In Figure 4B, ultrasonic energy is applied to the~system 44'~suc~ that the energy acts on the web 16,and~coating~18 in the region of initial contact 2~0~ between the web~16~and coating 18. The ultrasonic horn 20~replaces~the~backup roller 14 and the ultrasonic energy~is applied directly to the web 16 and excites the web 16 and coating 18 at the location of initial contact~between the coating 18 and the web ZS ~16. Moreover,~ an~ultrasonic slide die (not shown) in which the coating, 18 is excited while still within the slide~die and~the~energy travels through the coating ~; 18 to the region of initial contact between the coating 18 and the~web~l6 can be used.
Referring to Figure 5, a roll coating system : : : ~
,~ ~ 50 is shown. In~Figurë 5A, no ultrasonic excitation is provided. The~coating system 50 includes a pan 52 ' containing liqu~id coating material 18 and a roll 54 mounted for rotation within the pan 52. The backup :
W093/07969 PCT/USg2/07610 ~1 lG~2 -14-roller 14 is located adjacent the roll 54. The web 16 of material to be coated travels from left to right in the figure. The coating material 18 is applied to the web 16 across the desired width and a smoother or doctor blade 56 may be used to wipe off excess coating 18 and level or smooth the coating 18 on the web 16.
In Figure 5B, ultrasonic energy is applied to the system 5~' such that the energy acts on the web 16 and coating 18 in the region of initial contact between the web 16 and coating 18. This is accomplished by replacing the backup roller 14 with an : ultrasonic horn 20. The ultrasonic energy is applied directly to the~web 16 and excites the web 16 and coating 18 at the location of initial contact between ~ 15 ~ the coating lg and the web 16. Alternatively, when a :: ~dootor blade 56~is used as part of the coating :: applicator device lO to level or smooth the coating 18 on the web 16, application of ultrasonic energy can be beneficially applied:in the region of final contact 20:~ between the coated web 16 and the downweb doctor blade. Thus, when;the doctor blade is used, the ultrasonic~energy need not reach the region of initial contact:between~the:web 16 and the coating 18 as long as it reaches the region of final contact between the 25~ ~coated web 16 and~;the doctor blade. Ultrasonic energy also performs:well with other coating systems including those~with a plurality of rolls.
: Figures 6A, 6B, and 6C correspond to Figures : : lA, lB, and lC, respectively, and illustrate non-contact extrusion coating systems 60, 60'.
~: : In one~arrangement for all of the coating configurations,~the ultrasonic source is located at the line of initial contact between the coating material and the web. Preferably, the ultrasonic W~93/07~6g PCT/~S~2/07610 -15- ~1 1 G9 ~2 energy is applied at the backside of the web through an ultrasonic horn used in place of a backup roll or other support. However, the ultrasonic source can be located remotely from the initial contact line to S apply energy to the coated or uncoated web as long as sufficient ultrasonic energy reaches the line of initial contact. The maximum distance is about 15 cm although the best results have been found to occur within 8 cm. Alternatively, as discussed with respect to Figure 2, the ultrasonic energy can be applied within 15 cm of the location of any downweb leveling or-smoothing structure. Also, the ultrasonic energy can excite the area between the region of initial contact of the coating material and the web and the lS~ region of final contact between the coating applicator device or downweb structure and the coating material.
The ultrasonic energy can be applied at any one or a combination of these areas.
Regardless of the location of the u}trasonic energy source, the ultrasonic energy adds energy to the coating liquid. As the acoustic energy intensity increases, the coating quality and processability, including the thickness uniformity, improves until an optimum acoustic intensity level is reached. Acoustic energy preferably is applied near this optimum level which is at intensity levels between 0.1 W/cm2 and 40 W/cm2, depending on the kind of coater and the type of material being coated. However, the application of ultrasonic energy can create web vibrations such as surface acoustic waves which apply energy to the coating. Depending on the magnitude of the vibration, this can improve or degrade the coating quality. Care must be taken to avoid adverse affects such as lower W093/07969 PCT/USg2/07610 2~ GQ62 -16-frequency standing waves which yield coating nonuniformity.
The application of ultrasonic energy through a backup horn that generally replaces a backup roller S is the preferred arrangement in all coating configurations. The ultrasonic energy can be applied to the web by direct contact or through any medium which transmits a~sufficient amount of energy such as a coupli:ng fluid. The working surface of the horn itself, and also the web in contact with the horn, is at or near a pressure node in the acoustic standing wave. As the ultrasonic energy is transmitted and , :
reflected by the~web and the coating material, the combined waves~pull coating material toward the horn pressure node and toward the web. This improves drawdown in extrusion coating and provides a more stable liquid contact line in both extrusion and curtain coating.~The coating material is urged to the web and reduces~the~tendency for air entrainment 20 ~ between the~coating and the web. Other desirable effects that improve wettability include phenomena such~as ultrasonic viscosity reduction and contact line and~bulk fluid~dynamics with the associated fluid momentum contributions. Furthermore, because the horn 2~5 is a rigidly mounted, nonrotating, low friction surface, backup roll runout and the associated downweb variations are~eliminated. If desired, a carrier web could be used;to shield the moving coated web from the -~ stationary ultrasonic horn.
3~ I~f the~region of initial contact between the coating material and web is confined by another structure, as with the slot-fed knife system of Figures 3B and 3D, additional effects may occur.
Because the coating material forms a thin layer :, W093/0796g -17- 7f f 6 9 6 2 between two acoustically-matched materials, the transmission of acoustic energy is greatly enhanced.
The acoustic energy density in the coating material between the die and the web is much greater than that outside this region. Moreover, if a low coating weight or void streak occurs in the coating area, the acoustic energy density in this area is lower and an increased fluid crossflow occurs which fills in the streak. The increased energy density of the fluid in the coating area increases the crossweb flow, reduces streaks, reduces the tendency for air entrainment, and results in better~crossweb uniformity and a flow configuration~which is more resistant to external disturbances. Additionally, the system can operate 15~ with larger gaps between the die and the web. This permits operating with larger process tolerances as the die position is not as critical-as when ultrasonic ;energy is not used. The use of larger coating gaps reduces~web tear-out problems. Also, machining 20 ~ variations on the;die faces become a smaller percentage of the~`total coating qap and their adverse ; effect on coating uniformity is reduced.
:
The preferred frequency of vibration for the acousti~ enerqy ~is~at the low end of the ultrasonic ~25 ~ spectrum at 20,000 Hz. However, because the benefits of ultrasonically-assisted coating are not highly dependent on frequency, a broad range of high and low frequencies is functional. Although lower frequencies are audible and~present noise control problems, they can be used when higher amplitudes are required as with more viscous liquids or for scale-up of larger systems. Higher frequency ultrasonic systems present scale-up problems because they are smaller due to the shorter wavelengths that accompany higher frequencies.
WOg3/07g~9 PCT/US92/07610 21 i ~ ~ -18-However, high frequency systems may be preferred for lower viscosity (less than 500 cps) liquids as they generate fewer low frequency resonances.
Peak-to-peak amplitudes of ultrasonic vibration between 0.002 mm and 0.20 mm have been tested in ultrasonically-assisted coating. The higher amplitudes are more useful for highly viscous liquids or thin layers whereas lower viscosity liquids or thick layers require lower amplitudes. For example, in a slot-fed knife system with a S,000 cps solvent-based rubber coating, a peak-to-peak amplitude of 0.03 mm at 20,000 Hz is sufficient to observe the desired improvements in coating quality. If the amplitude is too large, coating uniformity can be disrupted by~localized nonuniformities such as rippling ef~fects.
The~angle~of input of the ultrasonic waves preferably is perpendicular to the direction of web travel, as shown ~in Figures ~B and lC. However, while 20~ this orientation~is preferred, the angle of input can range from perpendicular to parallel to the plane of ;the web l6. Figures lE and lF show systems similar to Figures lB and lC~in which the ultrasonic energy is transmitted through an ultrasonic horn 20 and an 25~ ultrasonic die~2~2,~respectively. In these embodiments, the horn 20 and the die 22 transmit the ;~ ultrasonic enerqy at an angle between 0 and 90. ln ` Figure lG, the~ultrasonic horn 20 transmits the -~
uItrasonic energy in a direction parallel to the plane ~ .
of the web 16 such that the amplitude of vibration of the ultrasonic energy lies in the direction of web 16 tra~el. ~
If~ultrasonic~energy is applied through the `-coating die (as in Figures lD and 3D) it also effects .
:
W~93/07969 PCT/US92/07610 the flow of coating material in the die. It h1sl ~ a~2 found that in some instances when the pumping force is held constant, the flow rate through the die is doubled when ultrasonic energy is applied parallel to the liquid motion and the flow rate is improved by a factor of five when it is applied in the perpendicular direction. In addition, ultrasonic excitation of the die increases the temperature of the coating material which improves the natural flow of coating from the die. Also, debris stuck in die crevices can be coaxed out of the die by ultrasonic excitation, thus ; eliminating the presence of streaks in the coated web due to trapped debris. The die is preferably excited as a standing wave. Alternatively, the ultrasonic vibrations can be appIied as a traveling wave propagating through the die, either with or without the use of a coupling material.
Many series of experiments with various fluids have been run. In one experiment, a 30 cm ~12 ~`20 in) wide knife die with an ultrasonic backup horn was -used. A rubber-based adhesive was coated at a web speed of 7.62 mlmin (25 ft/min) at 0.0635 mm (0.0025 ; in) thick. The~ultrasonic amplitude was about 0.0305 ~mm (0.0012 in) peak-to-peak. One area in the die was .
25 intentionally plugged for about 1 mm ~0.04 in) to ~-~ simulate a clogged die and demonstrate the ability of ; the ultrasonics to compensate with sufficient crossflow in the coating nip to mask streaks. Cross web coating thickness profiles were taken and are 30 illustrated in Figure 7. The coating width on the web -is shown along the x-axis and the coating thickness is shown along the y-axis. Figure 7A shows coating without ultrasonics. A streak at area A was caused by the plug in the~die orifice and a dip at area B was a W0~3~07969~ PCT/US92/07610 naturally occurring thin coating area in the web.
When the ultrasonics was turned on, the area A filled in to within 92% of the overall coating thickness and the area B dip was essentially eliminated, as shown in S Figure 7B.
Pilot plant data also was obtained. A run of 24,689 m (81,000 ft) of 61 cm ~24 in) wide rubber-based adhesive tape was made at 15.24 to 30.48 m/min (50 to 100 ft/min) using a slot fed knife die with an ultrasonic backup horn. The ultrasonic amplitude was varied between 0.015 and 0~025 mm (0.0006 and 0.001 ~inj peak-to-peak. The coating was 0.030 mm (0.0012~in)~ thick and crossweb profiles were measured. Ten consecutive scans of 230 data points each were taken noting the range of the coating : : : ~ :
thickness and~the standard deviation of the last scan, and the average range and standard deviation of all ten scans. (The~range is the minimum to maximum crossweb coating~thickness.) The~ten scan ~roups were 20 ~ ~performed 17 times with ultrasonics and 9 times without ultrasonics.
An indicatîon of transient coating thickness variation can be~determined by considering how much the range~of~a single scan varies from the average ;25 ~ range of severa~ scans before it. The coating range variations that~occur with time therefore can be indicated by subtracting the average range of the ten scans from the tenth scan of a group of ten scans, taking the absolute value, and dividing by the average range. This is~performed for all of the groups of ten scans, then averaged. Figure 8A compares the average range variation as a percentage for the scan groups with ultrasonics with the scan groups without ultrasonics. Ultrasonics reduces the percent :
.. . .. ... . . ... . ~ .. . , . ~ .. .. .. ~ . ... . .
W~93/07969 PCT/US92/07610 -21- 211 69~2 variation from 47% to 15%, a three-fold reduction.
Figure 8B compares the standard deviation variations of the runs with and without ultrasonics. The standard deviation variation percentages were reduced from 25~ to 10% when ultrasonics was used. These figures show the improved consistency of the overall crossweb caliper profile as a function of run time.
- Once a desired coating profile has been established, the profile varies less with time when ultrasonics is present than without ultrasonics.
Various~changes and modifications may be ~-effected therein~by one skilled in the art without departing from the scope or spirit of the invention.
~ For example, instead of using a sonotrode as the 15 ultrasonic energy source, eccentric cams or white ~-noise genera~tors~can be used to improve coatings.
Additionally, acoustic energy can be applied to both sides~of the web. ~
:
:
:
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: ~ .
f ~ .
Claims (16)
1. An apparatus (10', 26', 36', 44', 50', 60') for applying at least one layer of fluid coating material (18) having a substantially uniform crossweb thickness on only one surface of a moving web (16) comprising:
means (12, 28, 38, 46, 52, 54) for metering a controlled amount of coating material (18); and means (12, 28, 38, 46, 52, 54) for applying the metered amount of coating material onto at least a portion of only one surface of the web, said coating material application means operating separately from said metering means;
means (20) for acoustically exciting the line of initial contact between the coating material (18) and the web (16) at a substantially uniform acoustic intensity, while the coating material is fluid and before any substantial drying of the coating material occurs, wherein the acoustic intensity is selected in combination with the properties of the coating material (18) to create a coated web (16) having a sustantially uniform crossweb thickness perpendicular to the direction of movement of the web (16).
means (12, 28, 38, 46, 52, 54) for metering a controlled amount of coating material (18); and means (12, 28, 38, 46, 52, 54) for applying the metered amount of coating material onto at least a portion of only one surface of the web, said coating material application means operating separately from said metering means;
means (20) for acoustically exciting the line of initial contact between the coating material (18) and the web (16) at a substantially uniform acoustic intensity, while the coating material is fluid and before any substantial drying of the coating material occurs, wherein the acoustic intensity is selected in combination with the properties of the coating material (18) to create a coated web (16) having a sustantially uniform crossweb thickness perpendicular to the direction of movement of the web (16).
2. An apparatus (10', 26', 36', 44', 50', 60') for applying at least one layer of fluid coating material (18) having a substantially uniform crossweb thickness on only one surface of a moving web (16) comprising:
means (12, 28, 38, 46, 52, 54) for metering a controlled amount of coating material (18);
means (12, 28, 38, 46, 52, 54) for applying the metered amount of coating material onto at least a portion of, only one surface of the web, said coating material application means operating separately from said metering means; a downweb leveling structure (20, 32, 56); and means (20) for acoustically exciting at least one of the lines of initial contact between the coating material (18) and the web (16), the line of final contact between the downweb leveling structure (30, 32, 56) and the coating material (18), and any point between the lines of initial and final contact at a substantially uniform acoustic intensity, while the coating material is fluid and before any substantial drying of the coating material occurs, wherein the acoustic intensity is selected in combination with the properties of the coating material (18) to create a coated web (16) having a sustantially uniform crossweb thickness perpendicular to the direction of movement of the web (16).
means (12, 28, 38, 46, 52, 54) for metering a controlled amount of coating material (18);
means (12, 28, 38, 46, 52, 54) for applying the metered amount of coating material onto at least a portion of, only one surface of the web, said coating material application means operating separately from said metering means; a downweb leveling structure (20, 32, 56); and means (20) for acoustically exciting at least one of the lines of initial contact between the coating material (18) and the web (16), the line of final contact between the downweb leveling structure (30, 32, 56) and the coating material (18), and any point between the lines of initial and final contact at a substantially uniform acoustic intensity, while the coating material is fluid and before any substantial drying of the coating material occurs, wherein the acoustic intensity is selected in combination with the properties of the coating material (18) to create a coated web (16) having a sustantially uniform crossweb thickness perpendicular to the direction of movement of the web (16).
3. The apparatus (10', 26', 36', 44', 50', 60') of claim 2 wherein the exciting means (20) applies acoustic energy to the back surface of the web (16) to at least part of a region of the web (16) extending from fifteen cm upweb of the line of initial contact between the coating material (18) and the web (16) to fifteen cm downweb of the downweb leveling structure (30, 32, 56).
4. The apparatus (10', 26', 36', 44', 60') of claim 1 or 2 wherein the exciting means comprises a support comprising a backup horn (20) which supports the back surface of the moving web (16) and maintains substantial contact with the web (16) to apply acoustic energy to the coating material (18) from the exciting means (20) to the back surface of the web (16) through the web (16), and wherein the backup horn (20) is disposed substantially opposite the applying means (12, 28, 38, 46, 54) to apply acoustic energy to the back surface of the web (16) substantially at the point of initial contact between the coating material (18) and the web (16).
5. The apparatus (10', 26', 36', 44', 50', 60') of claim 1 or 2 wherein the exciting means (20, 22, 40) attracts the coating material (18) to the web (16), increases the flow into the microstructure and macrostructure of the web (16), and reduces air entrainment between the coating material (18) and the web (16).
6. The apparatus (10', 36') of claim 1 or 2 wherein the exciting means applies acoustic energy to the applying means (22,40) to create acoustic waves in the applying means (22, 40).
7. The apparatus (10', 26', 36', 44', 50', 60') of claim 1 or 2 wherein the exciting means (20, 22, 40) generates ultrasonic waves having substantially uniform amplitude and frequency with the frequency in the low end of the ultrasonic spectrum and the waves are perpendicular to the plane of the web (16).
8. The apparatus (10', 26', 36', 44', 50, 60,) of claim 1 or 2 wherein the exciting means (20, 22, 40) applies acoustic energy to the coating material through an energy transmissive coupling medium.
9. The apparatus (10', 26', 36', 44', 50', 60') of claim 1 or 2 wherein the applying means (12, 28, 38, 46, 52, 54) applies the metered amount of coating material (18) onto a plurality of portions of only one surface of the web (16) wherein the coated portions are discontinuous from each other in both the downweb and crossweb directions and wherein the exciting means (20, 22, 40) creates a coated web having a plurality of coated portions having a substantially uniform and equal crossweb thickness perpendicular to the direction of movement of the web (16).
10. A method of applying on only one surface of a moving web (16) at least one layer of fluid coating material (18) having a substantially uniform crossweb thickness comprising:
metering a controlled amount of coating material (18);
and applying, separately from the metering step, the metered amount of coating material (18) onto at least a portion of only one surface of the web (16);
acoustically exciting the line of initial contact between the coating material (18) and the web (16) from the surface opposite to the surface on which the coating material (18) is applied at a substantially uniform acoustic intensity while the coating material is fluid and before any substantial drying of the coating material occurs; and selecting the acoustic intensity in combination with the properties of the coating material (18) to create a coated web (16) having a substantially uniform crossweb thickness perpendicular to the direction of movement of the web (16).
metering a controlled amount of coating material (18);
and applying, separately from the metering step, the metered amount of coating material (18) onto at least a portion of only one surface of the web (16);
acoustically exciting the line of initial contact between the coating material (18) and the web (16) from the surface opposite to the surface on which the coating material (18) is applied at a substantially uniform acoustic intensity while the coating material is fluid and before any substantial drying of the coating material occurs; and selecting the acoustic intensity in combination with the properties of the coating material (18) to create a coated web (16) having a substantially uniform crossweb thickness perpendicular to the direction of movement of the web (16).
11. A method of applying on only one surface of a moving web (16) at least one layer of fluid coating material (18) having a substantially uniform crossweb thickness comprising:
metering a controlled amount of coating material (18);
and applying, separately from the metering step, the metered amount of coating material (18) onto at least a portion of only one surface of the web (16);
acoustically exciting at least one of the lines of initial contact; between the coating material (18) and the web (16), the line of final contact between the downweb leveling structure and the coating (18), and any point between the lines of initial and final contact, from the surface opposite to the surface on which the coating material (18) is applied at a substantially uniform acoustic intensity while the coating material is fluid and before any substantial drying of the coating material occurs; and selecting the acoustic intensity in combination with the properties of the coating material (18) to create a coated web (16) having a substantially uniform crossweb thickness perpendicular to the direction of movement of the web (16).
(leveling the coating material by means of a downweb leveling structure; and
metering a controlled amount of coating material (18);
and applying, separately from the metering step, the metered amount of coating material (18) onto at least a portion of only one surface of the web (16);
acoustically exciting at least one of the lines of initial contact; between the coating material (18) and the web (16), the line of final contact between the downweb leveling structure and the coating (18), and any point between the lines of initial and final contact, from the surface opposite to the surface on which the coating material (18) is applied at a substantially uniform acoustic intensity while the coating material is fluid and before any substantial drying of the coating material occurs; and selecting the acoustic intensity in combination with the properties of the coating material (18) to create a coated web (16) having a substantially uniform crossweb thickness perpendicular to the direction of movement of the web (16).
(leveling the coating material by means of a downweb leveling structure; and
12. The method of claim 11 wherein the exciting step comprises applying acoustic energy to at least part of a region of the web (16) extending from fifteen cm upweb of the line of initial contact between the coating material (18) and the web (16) to fifteen cm downweb of the downweb leveling structure (30, 32, 56).
13. The method of claim 10 or 11 wherein the exciting step comprises applying acoustic energy to the back surface of the web (16) while supporting and maintaining substantial contact with the back surface of the moving web (16) and applying acoustic energy to the coating material (18) through the web.
14. The method of claim 10 or 11 wherein the applying step comprises using an applying device (12, 28, 38, 46, 52, 54), and the exciting step comprises applying acoustic energy to the applying device to create acoustic waves in the applying device.
15. The method of claim 10 or 11 wherein the exciting step comprises exciting at ultrasonic levels and generating waves having substantially uniform amplitude and frequency at an angle with the web (16) ranging from perpendicular to the plane of the web (16) to parallel to the plane of the web (16).
16. The method of claim 10 or 11 wherein the applying step comprises applying the metered amount of coating material (18) onto a plurality of portions of only one surface of the web (16) wherein the coated portions are discontinuous from each other in both the downweb and crossweb directions, and wherein the exciting step creates a coated web having a plurality of coated portions having a substantially uniform and equal crossweb thickness perpendicular to the direction of movement of the web (16).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US77543691A | 1991-10-15 | 1991-10-15 | |
| US07/775,436 | 1991-10-15 | ||
| PCT/US1992/007610 WO1993007969A1 (en) | 1991-10-15 | 1992-09-09 | Ultrasonically assisted coating apparatus and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2116962A1 true CA2116962A1 (en) | 1993-04-29 |
Family
ID=25104421
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002116962A Abandoned CA2116962A1 (en) | 1991-10-15 | 1992-09-09 | Ultrasonically assisted coating apparatus and method |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP0608265B1 (en) |
| JP (1) | JP3302016B2 (en) |
| KR (1) | KR100215322B1 (en) |
| AU (1) | AU663116B2 (en) |
| BR (1) | BR9206633A (en) |
| CA (1) | CA2116962A1 (en) |
| CZ (1) | CZ67094A3 (en) |
| DE (1) | DE69212329T2 (en) |
| HU (1) | HUT68044A (en) |
| MX (1) | MX9205742A (en) |
| TW (1) | TW216404B (en) |
| WO (1) | WO1993007969A1 (en) |
| ZA (1) | ZA927084B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19627322C1 (en) * | 1996-06-26 | 1997-11-20 | Hielscher Gmbh | Method for controlled application of fluids onto sheet material, e.g. foils used in printing industry |
| DE10001620A1 (en) * | 2000-01-17 | 2001-07-19 | Abb Alstom Power Ch Ag | Process used for coating a blade of a gas turbine comprises exciting the base material during coating in an ultrasound frequency range using a transmitting head connected to a vibrator |
| US6942904B2 (en) * | 2001-12-11 | 2005-09-13 | Ultra Technology Europe Ab | Dry end surface treatment using ultrasonic transducers |
| KR100522453B1 (en) * | 2003-01-14 | 2005-10-20 | 넥슨 주식회사 | Method for impregnation of matters in wood utilizing sound vibration energy |
| CN106824686B (en) * | 2017-03-08 | 2023-04-25 | 江苏集萃有机光电技术研究所有限公司 | Device and method for removing protrusions on sprayed surface |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2017704A1 (en) * | 1970-04-14 | 1971-11-04 | ||
| JPS57187071A (en) * | 1981-05-13 | 1982-11-17 | Toshiba Corp | Paint film forming method |
| NL8202164A (en) * | 1982-05-27 | 1983-12-16 | Philips Nv | METHOD AND APPARATUS FOR TRANSPORTING AND DEPOSITING VISCOUS SUBSTANCES |
| JPH0410902A (en) * | 1990-04-27 | 1992-01-16 | Nec Kansai Ltd | Production of green sheet |
-
1992
- 1992-09-09 KR KR1019940701198A patent/KR100215322B1/en not_active IP Right Cessation
- 1992-09-09 EP EP92920236A patent/EP0608265B1/en not_active Expired - Lifetime
- 1992-09-09 WO PCT/US1992/007610 patent/WO1993007969A1/en not_active Application Discontinuation
- 1992-09-09 JP JP50644493A patent/JP3302016B2/en not_active Expired - Fee Related
- 1992-09-09 CZ CS94670A patent/CZ67094A3/en unknown
- 1992-09-09 DE DE69212329T patent/DE69212329T2/en not_active Expired - Fee Related
- 1992-09-09 AU AU26425/92A patent/AU663116B2/en not_active Ceased
- 1992-09-09 HU HU9401022A patent/HUT68044A/en unknown
- 1992-09-09 CA CA002116962A patent/CA2116962A1/en not_active Abandoned
- 1992-09-09 BR BR9206633A patent/BR9206633A/en not_active IP Right Cessation
- 1992-09-16 ZA ZA927084A patent/ZA927084B/en unknown
- 1992-09-21 TW TW081107436A patent/TW216404B/zh active
- 1992-10-07 MX MX9205742A patent/MX9205742A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| JP3302016B2 (en) | 2002-07-15 |
| TW216404B (en) | 1993-11-21 |
| AU663116B2 (en) | 1995-09-28 |
| DE69212329D1 (en) | 1996-08-22 |
| BR9206633A (en) | 1995-11-07 |
| WO1993007969A1 (en) | 1993-04-29 |
| CZ67094A3 (en) | 1994-07-13 |
| ZA927084B (en) | 1993-03-31 |
| HU9401022D0 (en) | 1994-07-28 |
| MX9205742A (en) | 1993-04-01 |
| EP0608265B1 (en) | 1996-07-17 |
| AU2642592A (en) | 1993-05-21 |
| JPH07500051A (en) | 1995-01-05 |
| DE69212329T2 (en) | 1997-03-06 |
| EP0608265A1 (en) | 1994-08-03 |
| KR100215322B1 (en) | 1999-08-16 |
| HUT68044A (en) | 1995-05-29 |
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