CA2135827C - Transfer roll coating color and a coated paper - Google Patents
Transfer roll coating color and a coated paper Download PDFInfo
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- CA2135827C CA2135827C CA002135827A CA2135827A CA2135827C CA 2135827 C CA2135827 C CA 2135827C CA 002135827 A CA002135827 A CA 002135827A CA 2135827 A CA2135827 A CA 2135827A CA 2135827 C CA2135827 C CA 2135827C
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- Prior art keywords
- color
- coating
- transfer roll
- viscosity
- coated
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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
- D21H19/00—Coated paper; Coating material
- D21H19/36—Coatings with pigments
- D21H19/38—Coatings with pigments characterised by the pigments
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D103/00—Coating compositions based on starch, amylose or amylopectin or on their derivatives or degradation products
- C09D103/04—Starch derivatives
Abstract
A transfer roll coating color comprising a pigment and an adhesive as main components, wherein an average aspect ratio of the pigment is 10 or less, the adhesive being a low viscosity starch adhesive, a solid content in the color being 58 weight % or higher, and a viscosity of the color determined at 60 rpm by using a No.4 rotor of a Brookfield.TM.
viscosimeter being 1,500cps or less, as well as a coated paper which is obtained by transfer roll coating the said color at an amount of 5 g/m2 or higher on one side.
viscosimeter being 1,500cps or less, as well as a coated paper which is obtained by transfer roll coating the said color at an amount of 5 g/m2 or higher on one side.
Description
., A TRANSFER ROLL COATING COLOR AND A COATED PAPER
Field of the Invention The present invention relates to the transfer roll coating color and the quality of coated paper. In more detail, the present invention relates tora transfer roll coating color comprising a novel composition as well as having high solid content and low viscosity and by which coating may be carried out during operation time without affecting the advantages of transfer roll coating, particularly a stable runnability at high speed machine coating, and furthermore relates to high coat weight as well as an excellent gloss, smoothness and printability comparable to those obtained by a blade coating.
Background of the Invention Paints used in conventional transfer roll coatings in which pigments and adhesives are.the main components are highly viscous similar to other coating colors, and characterized in that coat weights are generally low. As the pigment there may be used inorganic pigments such as kaolin, clay, precipitated calcium carbonate, ground calcium carbonate, titanium oxide, aluminium hydroxide, satine white, barium sulfate, magnesium oxide, talc and colloidal silica, as well as organic pigments such as plastic pigments and white urea resin pigments, which are generally used in admixture of two kinds or more. As adhesives, there may be mentioned water-soluble polymer such as casein, r .;, ,: , 1 .' r , , ,: r .,.. ~' . : . ~ '.~ , ,.,. ...., .,'~! .. ::.". '',:.. ' . ' ~.~. . ' '.lr,. .)t.y ~.':~ ~:., e~, ' v.
2i3582'~
oxidized starch, phosphoric esterized starch, soybean protein and carboxymethyl cellulose, as well as synthetic rubber latex such as so-called SBR type, MBR type or MSBR
type and acrylic latex, which are used in an amount of 10 50 weight ~ of the water-soluble macromolecule and 10~ 30 weight ~ of the latex based on 100 weight ~ of the pigment and are generally used in admixture thereof. Furthermore, additives such as an anti-foaming agent, a dispersant, a water-proofing agent, a preservative, a coloring agent and a lubricant may be added, if required, to prepare a color.
A solid content of the thus obtained transfer roll coati ng color is ~.0 ~.55 weight ~o, and a ratio between the pigment and the adhesive (a binder ratio) is such that the adhesive is 30~r50 weight ~ to the pigment, which means that the amount of the adhesive is considarably high.
Furthermore, a starch adhesive and latex are used together in many cases in the adhesive, and it is characterized that the ratio of the starch adhesive is as high as 20-~.50 weight ~ to the pigment. The starch adhesives generally used have a viscosity of at least 3,000 cps, generally 10,000 cps or higher, determined at a solid content of 30 weight ~, a temperature of 50 '~ and 60rpm by means of a No.4 rotor of a BrookfieldTT" viscosimeter. In addition, a ..
coated amount on one side is less than 5 g/m2, particularly less than 3~g/mz, for an effective coating, also being a characteristic thereof.
The transfer roll coating is thus known as suitable for _'' . " ~ , :: Z : ~ : ~ .:. ' ,:,: :1' ,,.:., .'.
a coating of a sizing liquid since a quite light weight coating is possible, and furthermore has many advantages such as (1) the device may be compact, (2) the coating may be carried out with wide webs, (3) on machine coating, (~t) with less paper break, and (5) a continuous operation is possible for several days, (6) a coating on both sides is easily achived, as well as (~) the difference between a surface and a back of a product being small. On the contrary, however, there are also some disadvantages such as (1) a feeling of a coated surface being inferior to that obtined by a blade coating,(2) characteristics of a color being limited, and (3) maintenance of rolls being necessary.
The coated surface obtained by the transfer roll coating has a specific stripy coating pattern, and may not give an even, smooth and glossy coated surface obtained in the case of the blade coating. The stripy pattern can be improved by increasing the coat weight, but a split pattern such as Orange peal or aventurine appearence may then appear and excellent printability cannot be obtained when the transfer roll coated paper is printed. Eor these reasons, in spite of having many advantages described above, the transfer roll coating has been used only for a sizing liquid coating or a light weight coating wherein a high _, coated amount is not necessary or for preparation of a low-grade coated paper wherein printability is not critical.
There has recently been a tendency for grade-up over all coated papers, and for example in art papers the so-. ; . 3; ,, , . ,'~ ..'; .
zi~~s27 called super art papers with more glossy and superior printability have been appeared and additionally higher opacity, stiffness and gloss are required even in the customary grades such as superlight weight coated papers.
This tendency is similar in the low-grade coated papers. Eor improvement in smoothness and gloss of the coated paper, a super calender or a machine calender has hitherto been used, and means such as increase in a calender pressure and a temperature are used to obtaine the more glossy coated papers. However, if these means are applied for the transfer roll coated paper, gloss may be improved somewhat, but calipers become short, as well as qualities such as opacity, whiteness, stiffness and ink acceptability are lowered, by which the problems are not improved at all.
The present inventors thus have studied the subject to supply stably a transfer roll coating color by which an even coated surface without any unevenness of coating surface can be obtained as well as a highly gloss and smooth coated surface can be obtained under a low pressure calendering condition without affecting any of the advantages of the tarnsfer roll coating, particularly a stable runnability at a high speed on machine, and also a coated paper with excellent printability comparable to those obtained by the blade coating method by coating the said color.
Generally, if the coat weight is increased, a more smooth surface can be obtained. The coat weight in the transfer roll coating is controlled by adjusting a nip . :; .: . .: 4 . . :; , ,:. . ., . : =, ° ~: ':
X13582'7 pressure between roll, circumferential speeds of each roll and a solid content in the color.
Therefore, the present inventors considered that increase in the coat weight could dissolve the above-mentioned subject and studied about to the nip pressure between rolls, the circumferential speeds and the solid content in the coating color. In the case that the nip pressure being lowered to enlarge the gap between rolls, the coat weight is increased but a ring-form pattern may be easily produced. In the case that circumferential speeds are differentiated, the feeling of the coated surface worsens. It is thus found that the coat weight may be only slightly controlled in practice by differentiating the nip pressure or circumferential speeds. Therefore, control of the coat weight is mainly due to a function of the solid content in the color. Then, for coating in a high coat weight, the solid content of coating should be increased.
However, if the solid content is increased in such a range of materials as used in the conventional transfer roll coating color, viscosity is also increased to produce a split pattern of the color on an aplicator roll. The said pattern not only appears on the coated surface to damage the feeling of the coated surface, but also produces boiling of ..
the coating, gum-up and scattering of color mists, by which a great advantage of the transfer roll coating namely , wide webs, a high speed and stable operation on the machine is not possible.
Then, by further study, the present inventors found that if the solid content is 58 weight % or higher and the viscosity of the color at the said solid content is 1,500 cps or less determined at 60 rpm by using a No. 4 rotor of a BrookfieldT'" viscosimeter, an even coating can be carried out to give a highly glossy and smooth coated surface under a low calendering condition without affecting the advantages of the transfer roll coating, particularly a high speed stable runnability on the machine, as well as to give a coated paper with excellent printing quality comparable to that obtained by the blade coating method. Furthermore, we found that the coating color wherein the solid content is 58 weight % or higher and the viscosity determined at 60 rpm by using the No. 4 rotor of a BrookfieldT"' viscosimeter is 1,500 cps or less can be obtained by use of a low viscosity adhesive, and also that a coated paper having a good feeling of the coated surface together with the viscosity can be obtained, to complete the present invention.
SUMMARY OF THE INVENTION
An object of an aspect of the present invention is to provide a transfer roll coating color comprising a pigment and an adhesive as main components, characterized in that a solid content in the color is 58 weight % or higher and in that a viscosity of the color determined at 60 rpm by using a No. 4 rotor of a BrookfieldT"' viscosimeter is 1,500 cps or less.
Another object of an aspect of the preset invention is to provide a transfer roll coating color comprising a pigment and an adhesive as main components, wherein the adhesive contains a starch adhesive and the said starch adhesive is a low viscosity starch adhesive with a viscosity less than 3,000 cps determined at a solid content of 30 weight % and a temperature of 50°C at 60 rpm by using a No.4 rotor of a BrookfieldTM viscosimeter.
Yet another object of an aspect of the present invention is to provide a coated paper obtained by coating a transfer roll coating color comprising a pigment and an adhesive as main components, wherein a solid content in the coating color is 58 weight % or higher and a viscosity of the color determined at 60 rpm by using a No. 4 rotor of a BrookfieldTM viscosimeter is 1,500 cps or less. The other objects become apparent by the following description.
In accordance with another aspect of the present invention, there is provided a transfer roll coating color composed mainly of pigments and adhesives, the transfer roll coating color wherein the adhesives are starch type adhesives having a coefficient of viscosity in the range of 580 cps or over and not exceeding 3,000 cps when measured under the following conditions:
viscometer: B-type viscometer (Brookfield~
viscometer);
#4 spindle: 60 rpm;
temperature: 50°C;
concentration of solid materials: 30 wt% or higher;
and the pigments have 10 or lower average aspect ratio and 1,500 cps or lower coefficient of viscosity when measured under the following conditions:
viscometer: B-type viscometer (BrookfieldTM
viscometer);
#4 spindle: 60 rpm; and concentration of solid materials: 58 wt~ or higher.
In accordance with another aspect of the present invention, there is provided a method of making a coated printing paper comprising the steps of:
preparing a raw paper;
preparing a color composed of a pigment and a starch adhesive having the following properties and a small amount of additives as necessary with 58 weight% or higher in solid components, and 1,500 cps or less in coefficient of viscosity when measured at 60 rpm by using a No.4 rotor of a BrookfieldT"" viscometer; the pigment:
or lower in average aspect ratio and containing calcium carbonate having 5 or lower in average aspect ratio and 3 ~m or less in average particle diameter as 30 weight % or higher of the total pigment, the starch adhesive:
3,000 cps or less in coefficient of viscosity when measured at 30 weight o or lower in concentration, at a temperature of 500C and at 60 rpm by using a No.4 rotor of a BrookfieldTM viscosimeter, and coating the color on both surfaces of the raw paper with 5 g/m2 or more in solid components per each surface by a transfer roll coater.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED
EMBODIMENTS
The adhesive used in the present invention should be a water-soluble adhesive which can increase a solid content without increasing viscosity when mixed with a pigment, and should produce a sufficient adhering strength for the pigment. By studying the properties of the coating color and properties of the coated surface when being transfer roll coated, we found that a starch adhesive with a viscosity of less than 3,000 cps (a Brookfield~" viscosimeter, &0 rpm, 50°C; hereinafter, the viscosity of the starch adhesive is determined under the said conditions) at the solid content in the adhesive of 30 weight ~ is most 7a preferably used in the present invention. The said viscosity is quite low, since the viscosity of the conventionally used starch adhesives at the solid content of 30 weight ~o is at least 3,000 cps and in many cases 10,000 cps or higher. As the said low viscosity starch adhesives, there may be mentioned denatured starches such as ethyl-etherized starch, hydroxy ethyl etherized starch and low viscosity oxidized starch, as well as denatured starch adhesives such as starch latex copolymers. Furthermore, from viewpoints of a strength in the coated surface and a printing gloss, the low viscosity starch adhesive is preferably used together with other adhesives, particularly with latex adhesives having relatively low viscosity and large adhering strength, rather than used alone. The amount of the adhesive used is varied according to the kind of the adhesive used and the kind of the pigment as well as the required qualities of the desired coated paper, so that it is not limited to 'a specified one. And, it is important that the viscosity of the obtained coating color at the solid content of 58 weight ~ being 1,500 cps or less.
Generally, coating can be carried out in the transfer roll coating even if the viscosity of the color is low. For example, a coating is carried out at a coating color viscosity of about 10 cp in a sizing liquid coating, and the viscosity is at most 100 cps. The reason why the coating may be carried out at such a low color viscosity is that an object of the sizing liquid coating is to increase . ', :, ,,, 8 ;' , - ~ z ~.~ ~'.
t ._,.. ' ,,,, ; - ~,., . .; ;,. ,. ,~, :~v ,..,.. ,.., ',::
-~ X13582'7 an inside strength and an outside strength. That is, since the inside strength is not increased unless the sizing liquid permeates into an inside of a base paper, the viscosity of the sizing liquid should be low. In the case of a pigment coating, if the viscosity of coating is too low, the amount of the permeated coating color into the base paper much increased, by which the color cannot be remain on the surface of the base paper and a coating distribution deteriorates. As a result, the smoothness of the paper becomes inferior to lose gloss of the paper and printability deteriorates also. Thus, the color used according to the present invention is desirable to have higher viscosity than that of the color used in the clear coating and be a level not to produce a roll pattern such as split pattern in the case of the transfer roll coating, namely from above 100 cps to below 1500 cps. In the viscosity of the pigment coating color, the effect of the starch adhesive is considerable, so that, the viscosity of the color may be varied considerably by the viscosity of the starch adhesive. The viscosity of the starch adhesive used in the said color is thus desirably from above 200 cps to being 3000 cps.
Generally, the pigment is dispersed in a concentration ..
of about '70~, and the starch is formulated in a concentration of about 35,x~ A concentration of latex is about 50~. These are mixed to prepare a final color. The suitable solid content as to each materials are however :.: ..: , . .. u, ::
. : ' , 9 . . , ~, ,: ;,, . . ;: , , .
.~ ~13582'~
limited. For example, if the pigment is used at a higher concentration of 80~ than the conventional one, there may be a tendency to exert undesirable influences such as undispersed materials. Furthermore, if the starch is cooked at a higher concentration, the viscosity is increased too much, which cannot produce an uniform starch solution. Therefore, it may be difficult to adjust the final solids the coating color to 70~ or higher, and the concentration of from above 58%a to below '70~ is practical as the concentration of the transfer roll coating color.
Generally, in the case that being used together with latex, the low viscosity denatured starch is preferably used in an amount of 1 ~15 weight ~ to the pigment. Even at 3 ~-9 weight ~, the required properties of the coating color and the required qualities of the coated paper can be obtained.
In the case of the starch latex copolymer, it can be used alone, and it is suitably used in an amount of 20~ 50 weight ~ to the pigment.
The pigment which can be used according to the present invention is not particularly~limited if an aspect ratio is small, and can be selected from the pigments conventionally used for the transfer roll coating. In addition, some kinds of pigments may be used in admixture .
according to the required qualities of the coated surface.
If the aspect ratio increases, the surface covering property becomes better but the flowability of the coating color decreases to produce a split pattern such as sprinkle-1 0 ' . °_ ,., 213582'7 shaded on an applicator roll at the time of the transfer roll coating. As a result, there is a tendency that an even and smooth coated surface is difficult to obtain, so that the use of a pigment with large aspect ratio is less preferable. If the average pigment size is large, the viscosity of the color becomes low but the evenness and the smoothness of the coated surface are affected. If the average pigment size becomes too small, the viscosity of the coating color increases to produce a split pattern such as Orange peal or aventurine appearance on an applicator roll at the time of the transfer roll coating, by which the even and smooth coated surface may also not be obtained.
Therefore, it is necessary to select a pigment with an appropriate aspect ratio and an average pigment size. Eor these points, kaolinite clay or talc which are conventionally advised for the coating pigment cannot be used alone, since the average aspect ratio thereof is large such as about 20 or about 30. The lower the aspect ratio, the more even coated paper with good printability can be obtained even if a pigment with small pigment size is used.
As the pigments suitable for use according to the present invention, there may be mentioned ground calcium carbonate, precipitated calcium carbonate, calcium sulfite, ..
pyrophilite and plastic pigments.wherein the aspect ratio is or lower and the average pigment size is about 0.1.5 ~t m. Among them, calcium carbonate wherein the average aspect ratio is 5 or lower, more preferably 3 or lower, and the . '.. , .~.~' S ', 1.
,~ . 1 1 , ~
.. '~ .. , ' .:., ',.~:. . . ~:' ~.;, average pigment size being about 0. 5 -r 2 ,~ m is preferably used. The other pigment which may be used with the said calcium carbonate has preferably a low aspect ratio, and from this point an organic pigment may be preferably used together. Furthermore, in the case of the higher requirements in gloss of the coated surface and opacity, a pigment having a relatively large aspect ratio such as kaolin may be used unless damaging characteristics of the transfer roll coating are affected. Even in such cases, the total aspect ratio of the pigment is preferably 10 or lower.
In the case of the pigments used together, the above-mentioned calcium carbonate is preferably used in an amount of 30 weight ~ or higher, more preferably ~0 weight % or higher, based on the total pigment. ' The pigment and the adhesive are mixed, and additives such as a water-proofing agent, an anti-foaming agent, a dispersant, a preservative, a coloring agent and a parting agent are added if required in an amount of about 0.1~. 2 weight ~, to give a final color. The thus obtained color has a viscosity of 1,500 cps~or less even if the color concentration is increased to 58 weight ~ or higher, which is suitable for the transfer roll coating.
The transfer roll coating used in the present invention is a coating method characterized in that a color supplied by a color supplying means is transferred via a metering means and optionally a smoothing means to an applicator roll and then the color on the roll is transferred against ,,. ,; -.1:2 ' . ; ~;, ,:
213582?
a support at a positive rotation. The color supplying means the metering means and the smoothing means are basically constituted by multiple rolls positively rotating against the applicator roll. However, in the case that the object is higher metering or smoothing, a reversibly rotating roll, rod, blade or an air may be arranged in a reverse direction. The present invention may be applied to them without any damage.
Coating of the color according to the present invention is carried out by setting two gate rolls at a specified distance in order to obtain for example the desired coated amount and controlling the relative speeds of the rolls. The color passes through the gate rolls to split the surface of the rolls, by which a half thereof is transferred along the transfer rolls to webs and the remaining half of the color is returned to a color tank. When the color according to the present invention is used, a high coat weight such as 5 g/mZ
or more which cannot be obtained by the conventional transfer roll coating can be obtained without affecting the high speed property of the transfer roll coating. And, by coating 5 g/mZ or more, the coated surface with a high smoothness, a high gloss and good printability can be obtained. The coated amount on one side is preferably 515 g/mZ, more preferably 6 ~ 12 g/mZ.
By using the transfer roll coating color according to the present invention, the coat weight can be increased without producing any uneveness of coating surface specific '. , ,:, 1., ,3 .: . .
-~, ~ ~ 213582' to the transfer roll coating. And, a high speed and stable operation on the machine may be realized without affecting any advantage of the transfer roll coating. Additionally, the coated paper obtained by coating the said transfer roll coating color can be used to achieve a high smoothness and a high gloss under a low calendering condition, and also the paper has a high opacity, a stiffness and printability, particularly an excellent printing gloss and no print mottle, to give a coated paper with high printability comparable to those obtained by blade coating. Therefore, by using the transfer roll coating known hitherto as the method to give a low-grade printing paper, a high-grade printing paper can be obtained, which is a suprising effect.
Furthermore, since the covered layer with a superior covering property can be obtained by a high speed and stable coating on machine, it is excellent for undercoating in the case of multi-layer coating on machine. The reason why the coated paper with a high gloss, a high smoothness and high printability can be obtained by using the transfer roll coating according to the present invention is not clear, but can be considered as follows.
The color according to the present invention is superior in flowability since a viscosity is low in spite -.
of a high solid content, so that even coating can be carried out by forming an even coated film at a roll distance of the transfer rolls. Also, a high coat weight such as 5 g/mz or more can be realized by controlling the t,> ~i .~5.'.~~' "' ~ ~:.. ~ 1 4.:: . ,:
. 2135827 roll distance and a circumferential speed because of the high solid content. Furthermore, since the solid content of the color is high, permeation of liquid component containing a binder into a base paper becomes less, to form a bulky coated layer. Therefore, if opacity increases, a stripy unevenness of coating surface specific to the transfer roll coating can be corrected by a low pressure calendering treatment, to give a high gloss and a high smoothness. Furthermore, a porous coating layer may be formed by a high solids coating, to supplement a decrease of an ink set due to an increase of a coat weight as well as to give a coated paper with good printability and superior printability since stiffness is increased.
Additionally, since the color according to the present invention has a viscosity range suitable for the transfer roll coating, there is not produced boiling of the color or color mists during coating. Since the solid content is high, an absolute water~content becomes less than that of the low solid content color, which causes less contaminant on a lead-out roll, an expander roll and an after dryer just after coating and less amount of water permeating into the coating base paper. Thus, a drying load becomes lighter, so that the high speed coating can be carry out in spite of increased coated amounts.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is illustrated in more detail by the following examples and comparative examples, which do ~ ; .1 5 .. .. . . ''. '.~'~' , t' ocj% 'sEi.n;~ ~t:~w . . -not limit the invention.
First, a formulating method of an adhesive solution used is described and then a formulating method of a transfer roll coating color and preparation examples of coated papers are described.
In the following examples, parts and ~ are by weight unless otherwise described. Furthemore, blending parts in tables are all based on solids.
[Fomulating of an adhesive solution]
Water was added to an adhesive to adjust a solid content to 30%, stirred and dissolved while keeping the temperature at 95 °G or higher. After being dissolved, the temperature was adjusted at 50'G, and a viscosity was determined at 60rpm with use of a BrookfieldT" viscosimeter.
Examples of low viscosity starch adhesives (1) ~.(3) and conventional starch adhesives (1) ~.(2) as well as determined results of the viscosity are shown in Table 1.
,~: 1 6 , . , . ,; .
213582'7 c o '~
U
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o +~ N
i ;~ a a~
i V I
o _ ~ .~:. o o I
U
k 6D I
r S, C
~ +~ O ' J ~'oo ~ U U !
rl~ -N
N tn r: , y ~ O
.r.y ~o O
U
O
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k N
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~ >3.
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N
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1?
=-~ 2135827 [Formulating of a transfer roll coating color) 0. t parts of a dispersant and 0. O~t parts of sodium hydroxide were added to a specified blended pigment and then dispersed in water by means of a Serie''" dispersing device, to formulate a pigment slurry with a content of 73~.
Then, the above-mentioned formulated adhesive solution as an adhesive and SH latex with a solid content of 50~a were added, and furthermore a lubricant and a water-proofing agent were added, and at last water was added, to formulate the target concentration and make a transfer roll coating color.
The preferable pigment used in the following examples and comparative examples is ground calcium carbonate with an average aspect ratio of 2 -r 6.
[Preparation of a coated paper]
By using the obtained color as described above and adjusting a gap between rolls and a circumferential speed to give the desired coat weight, 64 g/m2 of a fine base paper was coated at a speed of 600 m/min by the transfer roll coater. The obtained coat paper was subjected to a seasoning under conditions of 20 'g and 65% relative humidity for a day and night, and then subjected to a calendering treatment.
( Examples 1 ~.. 2, Comparative examp les t ~.. 2 Transfer roll coating color of Examples 1-r2 and Comparative examples t~ 2 were obtained according to the above-mentioned formulating method of the coating color by . 1 8 . _ : . ~ '~~.::;
y 213582?
using blends of pigments and adhesives shown in Table 2. In addition, coated papers were prepared,according to the above-mentioned preparation method of the coated paper as to each color. The viscosity of colors, smoothness of coated paper and printability (gloss, print mottle), determined or evaluated by the following determination and evaluation methods are shown in Table 2.
[Viscosity of the color, a determination method of a smoothness, evaluation method of printability]
[Viscosity of the color) A viscosity at a concentration of a color formulated was determined at a room temperature by means of a Brookfield T" viscosimeter at a rotation number of 60 rpm.
[Unevenness of coating surface]
An unevenness of coating surface in the coating surface of the coated paper was evaluated visually.
Do Unevenness of coating surface was not observed at all.
Q Unevenness of coating surface was hardly observed.
p Unevenness of coating surface was slightly observed.
X Unevenness of coating surface was clearly observed.
X X Unevenness of coating surface was severe and spotty.
[Smoothness]
1. 9 .. ' , ..- _ ..
2135~2'~
.~
Smoothness in the coating surface of the coated paper was determined by means of a Oken-sikiT" smoothness factor.
[Printing gloss]
Printing was carried out with a RI-IIT" type printing tester by using 0.4 cc of ink ftradename: TK MARK-cyan, available from Toyo Ink Co., Ltd.] on the coating surface of the coated paper, and after seasoning for a day and night, 75 ° gloss was determined by means of a glossmeter available from Murakami Shikisai Kenkyusho.
[Print-mottle]
Printing was carried out with a RI-IITM type printing tester by using 0.4 cc of ink ftradename: TK MARK-cyan, available from Toyo Thk Co., Ltd.] on the coating surface of the coated paper, and after seasoning for a day and night, print mottle was evaluated visually by a five points method ( 5 good ~..1 bad ).
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0 lr..~,. s d~ . . . . . ~ , ~~. ~ ~ ~~ ~~'~ . . ~ ~ . . - . ,Y . ~' --,, As is apparent from these examples'and comparative examples, the coated papers obtained by use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle. The color in comparative examples could be coated in 10 g/mz on one side, but unevenness of coating surface (split pattern) specific to the transfer roll coating was produced and print mottle was also increased. In addition, boiling was produced and runnability during coating was inferior since the viscosity of the color was high.
(Examples 3~~, Comparative examples 3~-~~
Color were formulated with the blending ratio of pigments and adhesives shown in Table 3, and then coated papers with coat weight of 5 g/mZ and 7.5 g/mz on one side were prepared as to each color.
Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table 3.
.~;.' .. ,~ ' .,~. . , t ' . ~ a ..
u' ~ X ~ ~
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o n ~ .c .,-~ U .,.~
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X ~ ~
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~ c t ~ ~
~ N
v > ~
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N X ~ ~
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a n ~ ~ O
N ~ ~
U
o ~ flf p~~ U r7 N ~ l ~
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~ ~a ~ N
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cb w ..
N i~ .1~ UJ L.
1~
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g o ' oo n. ~ s s~ ~
a N ~ ~ ~t~ U U V7 c .
p N ~ ~ ~ ~ ~
i~ ~ ~
N ~
1 O J-~ f r O .. ~.. ~ 1 ~
v1 u1 00 ~
cb .r.
8 C C ~ N
~ E
cd .C f/~ N C
cd ' ~
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r-t N 'Cy .-~ > $ ~"..~
U U L' ~ ~ ~ ~.. cd ~.
U ~ V1: fly U. U
> ~.
. 2 3 ; :. .
As is apparent from these examples, the coated paperes with use of the color according to the present invention were excellent in printability, particularly against print mottle. In Comperative examples 4, 6 and 8, smoothness and printing gloss could not be determined since unevenness of coating surface being occured. Furthermore, in the Comparative examples, stripy print mottle specific to the transfer roll coating was observed. Particularly, in the comparative examples 3 and 5, stripy unevenness of coating surface was severe and also print mottle was remarkable.
(Examples 5~-6, Comparative examples 9-rl4J
Color were formulated with the blending ratio of pigments and adhesives shown in Table 4, coated papers were prepared as to each color and then subjected to a calendering treatment under a high linear pressure.
Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table ~..
Field of the Invention The present invention relates to the transfer roll coating color and the quality of coated paper. In more detail, the present invention relates tora transfer roll coating color comprising a novel composition as well as having high solid content and low viscosity and by which coating may be carried out during operation time without affecting the advantages of transfer roll coating, particularly a stable runnability at high speed machine coating, and furthermore relates to high coat weight as well as an excellent gloss, smoothness and printability comparable to those obtained by a blade coating.
Background of the Invention Paints used in conventional transfer roll coatings in which pigments and adhesives are.the main components are highly viscous similar to other coating colors, and characterized in that coat weights are generally low. As the pigment there may be used inorganic pigments such as kaolin, clay, precipitated calcium carbonate, ground calcium carbonate, titanium oxide, aluminium hydroxide, satine white, barium sulfate, magnesium oxide, talc and colloidal silica, as well as organic pigments such as plastic pigments and white urea resin pigments, which are generally used in admixture of two kinds or more. As adhesives, there may be mentioned water-soluble polymer such as casein, r .;, ,: , 1 .' r , , ,: r .,.. ~' . : . ~ '.~ , ,.,. ...., .,'~! .. ::.". '',:.. ' . ' ~.~. . ' '.lr,. .)t.y ~.':~ ~:., e~, ' v.
2i3582'~
oxidized starch, phosphoric esterized starch, soybean protein and carboxymethyl cellulose, as well as synthetic rubber latex such as so-called SBR type, MBR type or MSBR
type and acrylic latex, which are used in an amount of 10 50 weight ~ of the water-soluble macromolecule and 10~ 30 weight ~ of the latex based on 100 weight ~ of the pigment and are generally used in admixture thereof. Furthermore, additives such as an anti-foaming agent, a dispersant, a water-proofing agent, a preservative, a coloring agent and a lubricant may be added, if required, to prepare a color.
A solid content of the thus obtained transfer roll coati ng color is ~.0 ~.55 weight ~o, and a ratio between the pigment and the adhesive (a binder ratio) is such that the adhesive is 30~r50 weight ~ to the pigment, which means that the amount of the adhesive is considarably high.
Furthermore, a starch adhesive and latex are used together in many cases in the adhesive, and it is characterized that the ratio of the starch adhesive is as high as 20-~.50 weight ~ to the pigment. The starch adhesives generally used have a viscosity of at least 3,000 cps, generally 10,000 cps or higher, determined at a solid content of 30 weight ~, a temperature of 50 '~ and 60rpm by means of a No.4 rotor of a BrookfieldTT" viscosimeter. In addition, a ..
coated amount on one side is less than 5 g/m2, particularly less than 3~g/mz, for an effective coating, also being a characteristic thereof.
The transfer roll coating is thus known as suitable for _'' . " ~ , :: Z : ~ : ~ .:. ' ,:,: :1' ,,.:., .'.
a coating of a sizing liquid since a quite light weight coating is possible, and furthermore has many advantages such as (1) the device may be compact, (2) the coating may be carried out with wide webs, (3) on machine coating, (~t) with less paper break, and (5) a continuous operation is possible for several days, (6) a coating on both sides is easily achived, as well as (~) the difference between a surface and a back of a product being small. On the contrary, however, there are also some disadvantages such as (1) a feeling of a coated surface being inferior to that obtined by a blade coating,(2) characteristics of a color being limited, and (3) maintenance of rolls being necessary.
The coated surface obtained by the transfer roll coating has a specific stripy coating pattern, and may not give an even, smooth and glossy coated surface obtained in the case of the blade coating. The stripy pattern can be improved by increasing the coat weight, but a split pattern such as Orange peal or aventurine appearence may then appear and excellent printability cannot be obtained when the transfer roll coated paper is printed. Eor these reasons, in spite of having many advantages described above, the transfer roll coating has been used only for a sizing liquid coating or a light weight coating wherein a high _, coated amount is not necessary or for preparation of a low-grade coated paper wherein printability is not critical.
There has recently been a tendency for grade-up over all coated papers, and for example in art papers the so-. ; . 3; ,, , . ,'~ ..'; .
zi~~s27 called super art papers with more glossy and superior printability have been appeared and additionally higher opacity, stiffness and gloss are required even in the customary grades such as superlight weight coated papers.
This tendency is similar in the low-grade coated papers. Eor improvement in smoothness and gloss of the coated paper, a super calender or a machine calender has hitherto been used, and means such as increase in a calender pressure and a temperature are used to obtaine the more glossy coated papers. However, if these means are applied for the transfer roll coated paper, gloss may be improved somewhat, but calipers become short, as well as qualities such as opacity, whiteness, stiffness and ink acceptability are lowered, by which the problems are not improved at all.
The present inventors thus have studied the subject to supply stably a transfer roll coating color by which an even coated surface without any unevenness of coating surface can be obtained as well as a highly gloss and smooth coated surface can be obtained under a low pressure calendering condition without affecting any of the advantages of the tarnsfer roll coating, particularly a stable runnability at a high speed on machine, and also a coated paper with excellent printability comparable to those obtained by the blade coating method by coating the said color.
Generally, if the coat weight is increased, a more smooth surface can be obtained. The coat weight in the transfer roll coating is controlled by adjusting a nip . :; .: . .: 4 . . :; , ,:. . ., . : =, ° ~: ':
X13582'7 pressure between roll, circumferential speeds of each roll and a solid content in the color.
Therefore, the present inventors considered that increase in the coat weight could dissolve the above-mentioned subject and studied about to the nip pressure between rolls, the circumferential speeds and the solid content in the coating color. In the case that the nip pressure being lowered to enlarge the gap between rolls, the coat weight is increased but a ring-form pattern may be easily produced. In the case that circumferential speeds are differentiated, the feeling of the coated surface worsens. It is thus found that the coat weight may be only slightly controlled in practice by differentiating the nip pressure or circumferential speeds. Therefore, control of the coat weight is mainly due to a function of the solid content in the color. Then, for coating in a high coat weight, the solid content of coating should be increased.
However, if the solid content is increased in such a range of materials as used in the conventional transfer roll coating color, viscosity is also increased to produce a split pattern of the color on an aplicator roll. The said pattern not only appears on the coated surface to damage the feeling of the coated surface, but also produces boiling of ..
the coating, gum-up and scattering of color mists, by which a great advantage of the transfer roll coating namely , wide webs, a high speed and stable operation on the machine is not possible.
Then, by further study, the present inventors found that if the solid content is 58 weight % or higher and the viscosity of the color at the said solid content is 1,500 cps or less determined at 60 rpm by using a No. 4 rotor of a BrookfieldT'" viscosimeter, an even coating can be carried out to give a highly glossy and smooth coated surface under a low calendering condition without affecting the advantages of the transfer roll coating, particularly a high speed stable runnability on the machine, as well as to give a coated paper with excellent printing quality comparable to that obtained by the blade coating method. Furthermore, we found that the coating color wherein the solid content is 58 weight % or higher and the viscosity determined at 60 rpm by using the No. 4 rotor of a BrookfieldT"' viscosimeter is 1,500 cps or less can be obtained by use of a low viscosity adhesive, and also that a coated paper having a good feeling of the coated surface together with the viscosity can be obtained, to complete the present invention.
SUMMARY OF THE INVENTION
An object of an aspect of the present invention is to provide a transfer roll coating color comprising a pigment and an adhesive as main components, characterized in that a solid content in the color is 58 weight % or higher and in that a viscosity of the color determined at 60 rpm by using a No. 4 rotor of a BrookfieldT"' viscosimeter is 1,500 cps or less.
Another object of an aspect of the preset invention is to provide a transfer roll coating color comprising a pigment and an adhesive as main components, wherein the adhesive contains a starch adhesive and the said starch adhesive is a low viscosity starch adhesive with a viscosity less than 3,000 cps determined at a solid content of 30 weight % and a temperature of 50°C at 60 rpm by using a No.4 rotor of a BrookfieldTM viscosimeter.
Yet another object of an aspect of the present invention is to provide a coated paper obtained by coating a transfer roll coating color comprising a pigment and an adhesive as main components, wherein a solid content in the coating color is 58 weight % or higher and a viscosity of the color determined at 60 rpm by using a No. 4 rotor of a BrookfieldTM viscosimeter is 1,500 cps or less. The other objects become apparent by the following description.
In accordance with another aspect of the present invention, there is provided a transfer roll coating color composed mainly of pigments and adhesives, the transfer roll coating color wherein the adhesives are starch type adhesives having a coefficient of viscosity in the range of 580 cps or over and not exceeding 3,000 cps when measured under the following conditions:
viscometer: B-type viscometer (Brookfield~
viscometer);
#4 spindle: 60 rpm;
temperature: 50°C;
concentration of solid materials: 30 wt% or higher;
and the pigments have 10 or lower average aspect ratio and 1,500 cps or lower coefficient of viscosity when measured under the following conditions:
viscometer: B-type viscometer (BrookfieldTM
viscometer);
#4 spindle: 60 rpm; and concentration of solid materials: 58 wt~ or higher.
In accordance with another aspect of the present invention, there is provided a method of making a coated printing paper comprising the steps of:
preparing a raw paper;
preparing a color composed of a pigment and a starch adhesive having the following properties and a small amount of additives as necessary with 58 weight% or higher in solid components, and 1,500 cps or less in coefficient of viscosity when measured at 60 rpm by using a No.4 rotor of a BrookfieldT"" viscometer; the pigment:
or lower in average aspect ratio and containing calcium carbonate having 5 or lower in average aspect ratio and 3 ~m or less in average particle diameter as 30 weight % or higher of the total pigment, the starch adhesive:
3,000 cps or less in coefficient of viscosity when measured at 30 weight o or lower in concentration, at a temperature of 500C and at 60 rpm by using a No.4 rotor of a BrookfieldTM viscosimeter, and coating the color on both surfaces of the raw paper with 5 g/m2 or more in solid components per each surface by a transfer roll coater.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED
EMBODIMENTS
The adhesive used in the present invention should be a water-soluble adhesive which can increase a solid content without increasing viscosity when mixed with a pigment, and should produce a sufficient adhering strength for the pigment. By studying the properties of the coating color and properties of the coated surface when being transfer roll coated, we found that a starch adhesive with a viscosity of less than 3,000 cps (a Brookfield~" viscosimeter, &0 rpm, 50°C; hereinafter, the viscosity of the starch adhesive is determined under the said conditions) at the solid content in the adhesive of 30 weight ~ is most 7a preferably used in the present invention. The said viscosity is quite low, since the viscosity of the conventionally used starch adhesives at the solid content of 30 weight ~o is at least 3,000 cps and in many cases 10,000 cps or higher. As the said low viscosity starch adhesives, there may be mentioned denatured starches such as ethyl-etherized starch, hydroxy ethyl etherized starch and low viscosity oxidized starch, as well as denatured starch adhesives such as starch latex copolymers. Furthermore, from viewpoints of a strength in the coated surface and a printing gloss, the low viscosity starch adhesive is preferably used together with other adhesives, particularly with latex adhesives having relatively low viscosity and large adhering strength, rather than used alone. The amount of the adhesive used is varied according to the kind of the adhesive used and the kind of the pigment as well as the required qualities of the desired coated paper, so that it is not limited to 'a specified one. And, it is important that the viscosity of the obtained coating color at the solid content of 58 weight ~ being 1,500 cps or less.
Generally, coating can be carried out in the transfer roll coating even if the viscosity of the color is low. For example, a coating is carried out at a coating color viscosity of about 10 cp in a sizing liquid coating, and the viscosity is at most 100 cps. The reason why the coating may be carried out at such a low color viscosity is that an object of the sizing liquid coating is to increase . ', :, ,,, 8 ;' , - ~ z ~.~ ~'.
t ._,.. ' ,,,, ; - ~,., . .; ;,. ,. ,~, :~v ,..,.. ,.., ',::
-~ X13582'7 an inside strength and an outside strength. That is, since the inside strength is not increased unless the sizing liquid permeates into an inside of a base paper, the viscosity of the sizing liquid should be low. In the case of a pigment coating, if the viscosity of coating is too low, the amount of the permeated coating color into the base paper much increased, by which the color cannot be remain on the surface of the base paper and a coating distribution deteriorates. As a result, the smoothness of the paper becomes inferior to lose gloss of the paper and printability deteriorates also. Thus, the color used according to the present invention is desirable to have higher viscosity than that of the color used in the clear coating and be a level not to produce a roll pattern such as split pattern in the case of the transfer roll coating, namely from above 100 cps to below 1500 cps. In the viscosity of the pigment coating color, the effect of the starch adhesive is considerable, so that, the viscosity of the color may be varied considerably by the viscosity of the starch adhesive. The viscosity of the starch adhesive used in the said color is thus desirably from above 200 cps to being 3000 cps.
Generally, the pigment is dispersed in a concentration ..
of about '70~, and the starch is formulated in a concentration of about 35,x~ A concentration of latex is about 50~. These are mixed to prepare a final color. The suitable solid content as to each materials are however :.: ..: , . .. u, ::
. : ' , 9 . . , ~, ,: ;,, . . ;: , , .
.~ ~13582'~
limited. For example, if the pigment is used at a higher concentration of 80~ than the conventional one, there may be a tendency to exert undesirable influences such as undispersed materials. Furthermore, if the starch is cooked at a higher concentration, the viscosity is increased too much, which cannot produce an uniform starch solution. Therefore, it may be difficult to adjust the final solids the coating color to 70~ or higher, and the concentration of from above 58%a to below '70~ is practical as the concentration of the transfer roll coating color.
Generally, in the case that being used together with latex, the low viscosity denatured starch is preferably used in an amount of 1 ~15 weight ~ to the pigment. Even at 3 ~-9 weight ~, the required properties of the coating color and the required qualities of the coated paper can be obtained.
In the case of the starch latex copolymer, it can be used alone, and it is suitably used in an amount of 20~ 50 weight ~ to the pigment.
The pigment which can be used according to the present invention is not particularly~limited if an aspect ratio is small, and can be selected from the pigments conventionally used for the transfer roll coating. In addition, some kinds of pigments may be used in admixture .
according to the required qualities of the coated surface.
If the aspect ratio increases, the surface covering property becomes better but the flowability of the coating color decreases to produce a split pattern such as sprinkle-1 0 ' . °_ ,., 213582'7 shaded on an applicator roll at the time of the transfer roll coating. As a result, there is a tendency that an even and smooth coated surface is difficult to obtain, so that the use of a pigment with large aspect ratio is less preferable. If the average pigment size is large, the viscosity of the color becomes low but the evenness and the smoothness of the coated surface are affected. If the average pigment size becomes too small, the viscosity of the coating color increases to produce a split pattern such as Orange peal or aventurine appearance on an applicator roll at the time of the transfer roll coating, by which the even and smooth coated surface may also not be obtained.
Therefore, it is necessary to select a pigment with an appropriate aspect ratio and an average pigment size. Eor these points, kaolinite clay or talc which are conventionally advised for the coating pigment cannot be used alone, since the average aspect ratio thereof is large such as about 20 or about 30. The lower the aspect ratio, the more even coated paper with good printability can be obtained even if a pigment with small pigment size is used.
As the pigments suitable for use according to the present invention, there may be mentioned ground calcium carbonate, precipitated calcium carbonate, calcium sulfite, ..
pyrophilite and plastic pigments.wherein the aspect ratio is or lower and the average pigment size is about 0.1.5 ~t m. Among them, calcium carbonate wherein the average aspect ratio is 5 or lower, more preferably 3 or lower, and the . '.. , .~.~' S ', 1.
,~ . 1 1 , ~
.. '~ .. , ' .:., ',.~:. . . ~:' ~.;, average pigment size being about 0. 5 -r 2 ,~ m is preferably used. The other pigment which may be used with the said calcium carbonate has preferably a low aspect ratio, and from this point an organic pigment may be preferably used together. Furthermore, in the case of the higher requirements in gloss of the coated surface and opacity, a pigment having a relatively large aspect ratio such as kaolin may be used unless damaging characteristics of the transfer roll coating are affected. Even in such cases, the total aspect ratio of the pigment is preferably 10 or lower.
In the case of the pigments used together, the above-mentioned calcium carbonate is preferably used in an amount of 30 weight ~ or higher, more preferably ~0 weight % or higher, based on the total pigment. ' The pigment and the adhesive are mixed, and additives such as a water-proofing agent, an anti-foaming agent, a dispersant, a preservative, a coloring agent and a parting agent are added if required in an amount of about 0.1~. 2 weight ~, to give a final color. The thus obtained color has a viscosity of 1,500 cps~or less even if the color concentration is increased to 58 weight ~ or higher, which is suitable for the transfer roll coating.
The transfer roll coating used in the present invention is a coating method characterized in that a color supplied by a color supplying means is transferred via a metering means and optionally a smoothing means to an applicator roll and then the color on the roll is transferred against ,,. ,; -.1:2 ' . ; ~;, ,:
213582?
a support at a positive rotation. The color supplying means the metering means and the smoothing means are basically constituted by multiple rolls positively rotating against the applicator roll. However, in the case that the object is higher metering or smoothing, a reversibly rotating roll, rod, blade or an air may be arranged in a reverse direction. The present invention may be applied to them without any damage.
Coating of the color according to the present invention is carried out by setting two gate rolls at a specified distance in order to obtain for example the desired coated amount and controlling the relative speeds of the rolls. The color passes through the gate rolls to split the surface of the rolls, by which a half thereof is transferred along the transfer rolls to webs and the remaining half of the color is returned to a color tank. When the color according to the present invention is used, a high coat weight such as 5 g/mZ
or more which cannot be obtained by the conventional transfer roll coating can be obtained without affecting the high speed property of the transfer roll coating. And, by coating 5 g/mZ or more, the coated surface with a high smoothness, a high gloss and good printability can be obtained. The coated amount on one side is preferably 515 g/mZ, more preferably 6 ~ 12 g/mZ.
By using the transfer roll coating color according to the present invention, the coat weight can be increased without producing any uneveness of coating surface specific '. , ,:, 1., ,3 .: . .
-~, ~ ~ 213582' to the transfer roll coating. And, a high speed and stable operation on the machine may be realized without affecting any advantage of the transfer roll coating. Additionally, the coated paper obtained by coating the said transfer roll coating color can be used to achieve a high smoothness and a high gloss under a low calendering condition, and also the paper has a high opacity, a stiffness and printability, particularly an excellent printing gloss and no print mottle, to give a coated paper with high printability comparable to those obtained by blade coating. Therefore, by using the transfer roll coating known hitherto as the method to give a low-grade printing paper, a high-grade printing paper can be obtained, which is a suprising effect.
Furthermore, since the covered layer with a superior covering property can be obtained by a high speed and stable coating on machine, it is excellent for undercoating in the case of multi-layer coating on machine. The reason why the coated paper with a high gloss, a high smoothness and high printability can be obtained by using the transfer roll coating according to the present invention is not clear, but can be considered as follows.
The color according to the present invention is superior in flowability since a viscosity is low in spite -.
of a high solid content, so that even coating can be carried out by forming an even coated film at a roll distance of the transfer rolls. Also, a high coat weight such as 5 g/mz or more can be realized by controlling the t,> ~i .~5.'.~~' "' ~ ~:.. ~ 1 4.:: . ,:
. 2135827 roll distance and a circumferential speed because of the high solid content. Furthermore, since the solid content of the color is high, permeation of liquid component containing a binder into a base paper becomes less, to form a bulky coated layer. Therefore, if opacity increases, a stripy unevenness of coating surface specific to the transfer roll coating can be corrected by a low pressure calendering treatment, to give a high gloss and a high smoothness. Furthermore, a porous coating layer may be formed by a high solids coating, to supplement a decrease of an ink set due to an increase of a coat weight as well as to give a coated paper with good printability and superior printability since stiffness is increased.
Additionally, since the color according to the present invention has a viscosity range suitable for the transfer roll coating, there is not produced boiling of the color or color mists during coating. Since the solid content is high, an absolute water~content becomes less than that of the low solid content color, which causes less contaminant on a lead-out roll, an expander roll and an after dryer just after coating and less amount of water permeating into the coating base paper. Thus, a drying load becomes lighter, so that the high speed coating can be carry out in spite of increased coated amounts.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is illustrated in more detail by the following examples and comparative examples, which do ~ ; .1 5 .. .. . . ''. '.~'~' , t' ocj% 'sEi.n;~ ~t:~w . . -not limit the invention.
First, a formulating method of an adhesive solution used is described and then a formulating method of a transfer roll coating color and preparation examples of coated papers are described.
In the following examples, parts and ~ are by weight unless otherwise described. Furthemore, blending parts in tables are all based on solids.
[Fomulating of an adhesive solution]
Water was added to an adhesive to adjust a solid content to 30%, stirred and dissolved while keeping the temperature at 95 °G or higher. After being dissolved, the temperature was adjusted at 50'G, and a viscosity was determined at 60rpm with use of a BrookfieldT" viscosimeter.
Examples of low viscosity starch adhesives (1) ~.(3) and conventional starch adhesives (1) ~.(2) as well as determined results of the viscosity are shown in Table 1.
,~: 1 6 , . , . ,; .
213582'7 c o '~
U
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o +~ N
i ;~ a a~
i V I
o _ ~ .~:. o o I
U
k 6D I
r S, C
~ +~ O ' J ~'oo ~ U U !
rl~ -N
N tn r: , y ~ O
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k N
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N
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1?
=-~ 2135827 [Formulating of a transfer roll coating color) 0. t parts of a dispersant and 0. O~t parts of sodium hydroxide were added to a specified blended pigment and then dispersed in water by means of a Serie''" dispersing device, to formulate a pigment slurry with a content of 73~.
Then, the above-mentioned formulated adhesive solution as an adhesive and SH latex with a solid content of 50~a were added, and furthermore a lubricant and a water-proofing agent were added, and at last water was added, to formulate the target concentration and make a transfer roll coating color.
The preferable pigment used in the following examples and comparative examples is ground calcium carbonate with an average aspect ratio of 2 -r 6.
[Preparation of a coated paper]
By using the obtained color as described above and adjusting a gap between rolls and a circumferential speed to give the desired coat weight, 64 g/m2 of a fine base paper was coated at a speed of 600 m/min by the transfer roll coater. The obtained coat paper was subjected to a seasoning under conditions of 20 'g and 65% relative humidity for a day and night, and then subjected to a calendering treatment.
( Examples 1 ~.. 2, Comparative examp les t ~.. 2 Transfer roll coating color of Examples 1-r2 and Comparative examples t~ 2 were obtained according to the above-mentioned formulating method of the coating color by . 1 8 . _ : . ~ '~~.::;
y 213582?
using blends of pigments and adhesives shown in Table 2. In addition, coated papers were prepared,according to the above-mentioned preparation method of the coated paper as to each color. The viscosity of colors, smoothness of coated paper and printability (gloss, print mottle), determined or evaluated by the following determination and evaluation methods are shown in Table 2.
[Viscosity of the color, a determination method of a smoothness, evaluation method of printability]
[Viscosity of the color) A viscosity at a concentration of a color formulated was determined at a room temperature by means of a Brookfield T" viscosimeter at a rotation number of 60 rpm.
[Unevenness of coating surface]
An unevenness of coating surface in the coating surface of the coated paper was evaluated visually.
Do Unevenness of coating surface was not observed at all.
Q Unevenness of coating surface was hardly observed.
p Unevenness of coating surface was slightly observed.
X Unevenness of coating surface was clearly observed.
X X Unevenness of coating surface was severe and spotty.
[Smoothness]
1. 9 .. ' , ..- _ ..
2135~2'~
.~
Smoothness in the coating surface of the coated paper was determined by means of a Oken-sikiT" smoothness factor.
[Printing gloss]
Printing was carried out with a RI-IIT" type printing tester by using 0.4 cc of ink ftradename: TK MARK-cyan, available from Toyo Ink Co., Ltd.] on the coating surface of the coated paper, and after seasoning for a day and night, 75 ° gloss was determined by means of a glossmeter available from Murakami Shikisai Kenkyusho.
[Print-mottle]
Printing was carried out with a RI-IITM type printing tester by using 0.4 cc of ink ftradename: TK MARK-cyan, available from Toyo Thk Co., Ltd.] on the coating surface of the coated paper, and after seasoning for a day and night, print mottle was evaluated visually by a five points method ( 5 good ~..1 bad ).
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-> > ~ b ~H
~
cd td x V 'p ~ G 0 O
~ 3 ~ O U
> ~ ~
Q
V ~ ~ t .
.
0 lr..~,. s d~ . . . . . ~ , ~~. ~ ~ ~~ ~~'~ . . ~ ~ . . - . ,Y . ~' --,, As is apparent from these examples'and comparative examples, the coated papers obtained by use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle. The color in comparative examples could be coated in 10 g/mz on one side, but unevenness of coating surface (split pattern) specific to the transfer roll coating was produced and print mottle was also increased. In addition, boiling was produced and runnability during coating was inferior since the viscosity of the color was high.
(Examples 3~~, Comparative examples 3~-~~
Color were formulated with the blending ratio of pigments and adhesives shown in Table 3, and then coated papers with coat weight of 5 g/mZ and 7.5 g/mz on one side were prepared as to each color.
Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table 3.
.~;.' .. ,~ ' .,~. . , t ' . ~ a ..
u' ~ X ~ ~
W > X ~ ~
o n ~ .c .,-~ U .,.~
n ~ ~ ~
N ~
(~. ~ C1 ~ N ~ fb L
N
N.7.~,C~ O
Lt1 ? U~ '~ N r- LC1 ~ ~ ~
~
N ~t .~ O ~'N
X ~ ~
O
>
M ~
...~ U .-i ~
N ~M ~
~
~ E N~N U N'-"' tl~
~ c t ~ ~
~ N
v > ~
N. k tI~ U1 ' ~' tI1 U
W cd X N
tn ~ O M .-U
N X ~ ~
, X ~ ~
'..i C~
>
p U
...
a n ~ ~ O
N ~ ~
U
o ~ flf p~~ U r7 N ~ l ~
I,(1 /] b v N M LCD
~ f M
co ~ ~ X m m ,-a~
H
N ~
~ ~a ~ N
lf1 .
~
> V1 'C7 ~M 6 '~
~
V
cb w ..
N i~ .1~ UJ L.
1~
~
.L~U U . U .4~
g o ' oo n. ~ s s~ ~
a N ~ ~ ~t~ U U V7 c .
p N ~ ~ ~ ~ ~
i~ ~ ~
N ~
1 O J-~ f r O .. ~.. ~ 1 ~
v1 u1 00 ~
cb .r.
8 C C ~ N
~ E
cd .C f/~ N C
cd ' ~
, x ,d .
O .L~ 1~
r-t N 'Cy .-~ > $ ~"..~
U U L' ~ ~ ~ ~.. cd ~.
U ~ V1: fly U. U
> ~.
. 2 3 ; :. .
As is apparent from these examples, the coated paperes with use of the color according to the present invention were excellent in printability, particularly against print mottle. In Comperative examples 4, 6 and 8, smoothness and printing gloss could not be determined since unevenness of coating surface being occured. Furthermore, in the Comparative examples, stripy print mottle specific to the transfer roll coating was observed. Particularly, in the comparative examples 3 and 5, stripy unevenness of coating surface was severe and also print mottle was remarkable.
(Examples 5~-6, Comparative examples 9-rl4J
Color were formulated with the blending ratio of pigments and adhesives shown in Table 4, coated papers were prepared as to each color and then subjected to a calendering treatment under a high linear pressure.
Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table ~..
2 4 ;. ,. .:, y >:: : .. . . ~;:
213582' X I
i y > X I
o I
-' n ~ ~
,a U ,-I
n ~ ~
~. ~ C cd N N tf~
N r- ~
O J.-> .G O
~
> U7 'b N O~ U1 cd U
c~, 'r ''' X I
I
O
o X I
~ I
m ~
U rl n N
L~.~ l ~N ~~ ~ ~ ~'-'t~~
E
O 1.~ _C N
v ~ ~ ~ ~ N ~tt~
"' ~ ~ ~m V ~
~ ~ X I
I
p ?
N
X I
I
O U ~
~
L(1 N C U ~.. l~
Lf1 U7 O
N
c '- "_, ~' ~ ~ m ~
~ ~
. _ .~
> !I7 'CJ N N LIl X
-~ m _ .
O
U
E"' OOCO~
O
N ~' N 1f1 O ~
~ ~ ~N
~ ~
~.~
(V
~ ~ LI1 ~
O
Lf3 ~ 3 f1 M
l O
x ' U
tb W ..
d O
~
\ ue 00 ~1 ~
.. 0 .. C
t V U U 1~ f . .
., ~
~ ~ U U c t~ 0 O ~ O ~
213582' X I
i y > X I
o I
-' n ~ ~
,a U ,-I
n ~ ~
~. ~ C cd N N tf~
N r- ~
O J.-> .G O
~
> U7 'b N O~ U1 cd U
c~, 'r ''' X I
I
O
o X I
~ I
m ~
U rl n N
L~.~ l ~N ~~ ~ ~ ~'-'t~~
E
O 1.~ _C N
v ~ ~ ~ ~ N ~tt~
"' ~ ~ ~m V ~
~ ~ X I
I
p ?
N
X I
I
O U ~
~
L(1 N C U ~.. l~
Lf1 U7 O
N
c '- "_, ~' ~ ~ m ~
~ ~
. _ .~
> !I7 'CJ N N LIl X
-~ m _ .
O
U
E"' OOCO~
O
N ~' N 1f1 O ~
~ ~ ~N
~ ~
~.~
(V
~ ~ LI1 ~
O
Lf3 ~ 3 f1 M
l O
x ' U
tb W ..
d O
~
\ ue 00 ~1 ~
.. 0 .. C
t V U U 1~ f . .
., ~
~ ~ U U c t~ 0 O ~ O ~
a N J.~ O ~
1.~ O
. F.a .G W e--1 .-1 ~0 G 1 O ri 00 ~
O ~ j ~L' V~l U ~, ? ~ ~
~ B .1-~
~
~
.a . e N O C.
.. (d . 00 t O
t U ~
~ cd ~ O ~ C
cd ~
G ~
., ~ ' b .~ .L~
., -~ y . t 'es m s ~ v ~ ~n U
' a a .-~
~n ..:1r ,....,. ' . . ~~.::. . .... . ,.- , , ~.: ., ,.,..' ... ....
213582?
As is apparent from these examples, the coated paperes with use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle, even after being subjected to the calendering treatment under the high linear pressure. On the contrary, in Comperative examples ~., 6 and 8, smoothness and printing gloss could not be determined since unevenness of coating surface occured.
Furthermore, in the comparative examples, stripy print mottle specific to the transfer roll coating was observed, and could not be improved after being subjected to the calendering treatment under the high linear pressure, as well as being inferior in printability. Particularly, in Comparative examples 3 and 5, stripy unevenness of coating surface was severe and also print mottle was marked.
Examples 7~9, Comparative examples 15~20J
In Examples 7~9 and,Comparative examples 15 -r 20, color was formulated with the blending ratio of pigments and adhesives shown in Table 5, transfer roll coated at a coating speed of 1000 m/min. by means of a practical on-machine coater, and subjected to a soft calendering treatment under a linear pressure of 30 kg/cm. Comparative examples 18... 20 were commercially available products , according to a blade coating having the same grades as in the Examples.
Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or ,~ ,...' , . , ., .. . . 2 6 r ...v; '°' , . , ;. . . : .
213582' evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table 5.
r ::..: ; ';' ~..,' ?. ._ 2 7 ~ ; :' . «:' , ,y ,,, '=., 213582' ...... . . . o f/~
r1 Q' O , . . . O\ Lh ; .
~ M
vO
. . ~
W . . . . . . . . . .
.
N O
r r' - ~ a, "~.' ~ M
o ~
r , LI1~OM
., m .? L~O~NN~-C1.
B
O
U O
r-i L(1 M LCD ~
L(~ V ~ ~ X ~ ~
l11 O J.~ S. UI O N
~
~ U ~ ~
~
~
N~ N
C~ ~
~
.
.
N
> U1 'O
C c0 O
U O
~N~~ ~ )( ~~N
~
,~ ~I11N ~
U
'O ,.-~~ !~1 ~D lC~ Lh M tf1 tn OL vOOMN~tf~ ~~ ~
~ ~
~
CY ~ r- Lt1 Nl ll ~
Q.
> O
O
i~ ~
~.. ~
~D111~0~' f..
~' ~ ~ ~ N ~ ~ ~ N Lmtl ~ ~
~
v ..
-~
> V! 'C~
w D LI1 ~ ~
O O N
~
~ ~ ~ N ~ ~ ~ tt1 ~ N lf1 ~ x o ..
o ~ o0 r' '~
s'~
t~
.
. U
E 'N 'N O Se (~l U
~C U U U7 r ~ ..
f.
N
U ~ t~l~ U
U > t%~ ~.
p > 01 p N
1'~.a d V W ..1 ~ G H
~
~
~ 'O J~ y1 ~ ~ O ~
> ~ >
.. ~ N ~ ~
i U O
DC O
U
~
~
U ~ N . -~
r- -~
~ v a ~ V0 ~ t~O.O.
U >
U
f ;,i x r k ~,- a.~. . ~~r ,u.,.
a k.~-,..2 8 ,~..:' ~r,. ~ ,. ,. .~:k.,...
... ' ... . , , :" . ;.:
,~ '~ ~ ~, . ~... , As is apparent from these examples, the coated paperes with use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle. In addition,. the papers according to the present invention had equal or higher printability when compared with the commercially available products obtained by the blade coating, that is, which is superior to those of the transfer roll coated products.
furthermore, the said papers according to the present invention could be prepared without separating a base paper preparation procedure and a coating procedure such as used in the conventional blade coating. Additionally, a speed of on-machine-transfer roll coating according to the present invention was equal to a speed according to the blade coating, and a wide high speed coating which surpassed the blade coating could be carried out.
(Examples 10 ~13, Comparative examples 21 ~.24) Colors were formulated with the blending ratio of pigments and adhesives shown in Table 6, and coated papers with coat weight of 5 g/mZ and~8 g/mz on one side were prepared as to each colors.
Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table 6.
. .. , , ~.. ~.;. :.. ; ., . 2 9.. ;: ;: ~ :~~. f~ ~. . ..- .., ', ,;:., ~ l(1 y0 O
O N
N
~ >
t~' ,-i .~ n O~
~ ~~ ~ ~ ~' ~
~
~
X ~-OM
L
cu O yr O
O
N O~ L(1 X ~
~MN
cb a o U
N
~
Q~oM
,r ~ M ~- M
N
~~~ ~ U~
~ tf1 ~
~
O
> U M
3 cd ~ M lf1 O ~ O~
lf~ M
~
i ~ -' - M
a a~
.a co x ~ mn H ,~ a0 ~
W ' ~
~
~ v~l .~ > ~ ~
O U ~.-~ O
~
U
G.
O
I
O U
N M
~a > V~ 'D 00 L!1 ~
~MM _ O
r-I x, O
O N
U
cb w ..
O ~ p ~
i~
O 8'C
O U a Q
~~ ~ . ti fly t d O
0 ~ ~ U1 C
~ v O ~
~
.1~. 0 .. .C ' r 0 .t-~ f ~ ~~mi~ ' t ~ Nfl 0 Q
.t . o~ ~ ~ o0 ~.
r a ~ ~ ~
~ ~
~ ~ . b ~ + .N c c ~ o ~ ~ ~
~ g ~
o ~ ~ i .
~ ~ , C U ~ ~ U ~ ~ Q. U
1 d.
>
~. .. 3~ ., _,,...
As is apparent from these examples, the coated paperes with use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle. In Comparative examples 21 and 2~, the coat weight of 8 g/mz could not coated due to the structure of the transfer coating machine.
Furthermore, in Comparative examples 22 and 23, unevenness of coating surface occured and stripy print mottle specific to the transfer roll coating was observed.
(Examples 14.1'7, Comparative examples 25~J30) Color were formulated with the blending ratio of pigments and adhesives shown in Table 7, and coated papers with coat weight of 6 g/mz and 7.5 g/mz on one side were prepared as to each color. Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table 7. ' z13582~
~ '_'' X ~c?m o c ~
a > X ~
o s ~ c ..~ v ..~ o ..
O O
cri ~ N
~ ,~
~ m V
> m X
v c> m c~
~ X m N ~
a~
a X ~ O N
N ~ .-m o o ~ m > m ~ m m X N
L N L(~ ~ M
c0 a E
O
U Its c~ > N
1.~ O
. F.a .G W e--1 .-1 ~0 G 1 O ri 00 ~
O ~ j ~L' V~l U ~, ? ~ ~
~ B .1-~
~
~
.a . e N O C.
.. (d . 00 t O
t U ~
~ cd ~ O ~ C
cd ~
G ~
., ~ ' b .~ .L~
., -~ y . t 'es m s ~ v ~ ~n U
' a a .-~
~n ..:1r ,....,. ' . . ~~.::. . .... . ,.- , , ~.: ., ,.,..' ... ....
213582?
As is apparent from these examples, the coated paperes with use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle, even after being subjected to the calendering treatment under the high linear pressure. On the contrary, in Comperative examples ~., 6 and 8, smoothness and printing gloss could not be determined since unevenness of coating surface occured.
Furthermore, in the comparative examples, stripy print mottle specific to the transfer roll coating was observed, and could not be improved after being subjected to the calendering treatment under the high linear pressure, as well as being inferior in printability. Particularly, in Comparative examples 3 and 5, stripy unevenness of coating surface was severe and also print mottle was marked.
Examples 7~9, Comparative examples 15~20J
In Examples 7~9 and,Comparative examples 15 -r 20, color was formulated with the blending ratio of pigments and adhesives shown in Table 5, transfer roll coated at a coating speed of 1000 m/min. by means of a practical on-machine coater, and subjected to a soft calendering treatment under a linear pressure of 30 kg/cm. Comparative examples 18... 20 were commercially available products , according to a blade coating having the same grades as in the Examples.
Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or ,~ ,...' , . , ., .. . . 2 6 r ...v; '°' , . , ;. . . : .
213582' evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table 5.
r ::..: ; ';' ~..,' ?. ._ 2 7 ~ ; :' . «:' , ,y ,,, '=., 213582' ...... . . . o f/~
r1 Q' O , . . . O\ Lh ; .
~ M
vO
. . ~
W . . . . . . . . . .
.
N O
r r' - ~ a, "~.' ~ M
o ~
r , LI1~OM
., m .? L~O~NN~-C1.
B
O
U O
r-i L(1 M LCD ~
L(~ V ~ ~ X ~ ~
l11 O J.~ S. UI O N
~
~ U ~ ~
~
~
N~ N
C~ ~
~
.
.
N
> U1 'O
C c0 O
U O
~N~~ ~ )( ~~N
~
,~ ~I11N ~
U
'O ,.-~~ !~1 ~D lC~ Lh M tf1 tn OL vOOMN~tf~ ~~ ~
~ ~
~
CY ~ r- Lt1 Nl ll ~
Q.
> O
O
i~ ~
~.. ~
~D111~0~' f..
~' ~ ~ ~ N ~ ~ ~ N Lmtl ~ ~
~
v ..
-~
> V! 'C~
w D LI1 ~ ~
O O N
~
~ ~ ~ N ~ ~ ~ tt1 ~ N lf1 ~ x o ..
o ~ o0 r' '~
s'~
t~
.
. U
E 'N 'N O Se (~l U
~C U U U7 r ~ ..
f.
N
U ~ t~l~ U
U > t%~ ~.
p > 01 p N
1'~.a d V W ..1 ~ G H
~
~
~ 'O J~ y1 ~ ~ O ~
> ~ >
.. ~ N ~ ~
i U O
DC O
U
~
~
U ~ N . -~
r- -~
~ v a ~ V0 ~ t~O.O.
U >
U
f ;,i x r k ~,- a.~. . ~~r ,u.,.
a k.~-,..2 8 ,~..:' ~r,. ~ ,. ,. .~:k.,...
... ' ... . , , :" . ;.:
,~ '~ ~ ~, . ~... , As is apparent from these examples, the coated paperes with use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle. In addition,. the papers according to the present invention had equal or higher printability when compared with the commercially available products obtained by the blade coating, that is, which is superior to those of the transfer roll coated products.
furthermore, the said papers according to the present invention could be prepared without separating a base paper preparation procedure and a coating procedure such as used in the conventional blade coating. Additionally, a speed of on-machine-transfer roll coating according to the present invention was equal to a speed according to the blade coating, and a wide high speed coating which surpassed the blade coating could be carried out.
(Examples 10 ~13, Comparative examples 21 ~.24) Colors were formulated with the blending ratio of pigments and adhesives shown in Table 6, and coated papers with coat weight of 5 g/mZ and~8 g/mz on one side were prepared as to each colors.
Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table 6.
. .. , , ~.. ~.;. :.. ; ., . 2 9.. ;: ;: ~ :~~. f~ ~. . ..- .., ', ,;:., ~ l(1 y0 O
O N
N
~ >
t~' ,-i .~ n O~
~ ~~ ~ ~ ~' ~
~
~
X ~-OM
L
cu O yr O
O
N O~ L(1 X ~
~MN
cb a o U
N
~
Q~oM
,r ~ M ~- M
N
~~~ ~ U~
~ tf1 ~
~
O
> U M
3 cd ~ M lf1 O ~ O~
lf~ M
~
i ~ -' - M
a a~
.a co x ~ mn H ,~ a0 ~
W ' ~
~
~ v~l .~ > ~ ~
O U ~.-~ O
~
U
G.
O
I
O U
N M
~a > V~ 'D 00 L!1 ~
~MM _ O
r-I x, O
O N
U
cb w ..
O ~ p ~
i~
O 8'C
O U a Q
~~ ~ . ti fly t d O
0 ~ ~ U1 C
~ v O ~
~
.1~. 0 .. .C ' r 0 .t-~ f ~ ~~mi~ ' t ~ Nfl 0 Q
.t . o~ ~ ~ o0 ~.
r a ~ ~ ~
~ ~
~ ~ . b ~ + .N c c ~ o ~ ~ ~
~ g ~
o ~ ~ i .
~ ~ , C U ~ ~ U ~ ~ Q. U
1 d.
>
~. .. 3~ ., _,,...
As is apparent from these examples, the coated paperes with use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle. In Comparative examples 21 and 2~, the coat weight of 8 g/mz could not coated due to the structure of the transfer coating machine.
Furthermore, in Comparative examples 22 and 23, unevenness of coating surface occured and stripy print mottle specific to the transfer roll coating was observed.
(Examples 14.1'7, Comparative examples 25~J30) Color were formulated with the blending ratio of pigments and adhesives shown in Table 7, and coated papers with coat weight of 6 g/mz and 7.5 g/mz on one side were prepared as to each color. Viscosity of color, smoothness of coated papers and printability (gloss, print mottle) were determined or evaluated by the determination and evaluation methods similar to those in Example 1, and results are shown in Table 7. ' z13582~
~ '_'' X ~c?m o c ~
a > X ~
o s ~ c ..~ v ..~ o ..
O O
cri ~ N
~ ,~
~ m V
> m X
v c> m c~
~ X m N ~
a~
a X ~ O N
N ~ .-m o o ~ m > m ~ m m X N
L N L(~ ~ M
c0 a E
O
U Its c~ > N
m ~ m O
lt1 N
N v !~
N
d y 0 N
~ V
N ~ M
"
N ~
O ~., N
O
N
O ~
O
O U O
H
> N
~
.-r O
r-1 Gl .
~' ~ ~ ~ E
.-r U
~- v0 ~ X
N lf~
O
O ~ ~ ~' O
O
.N
O
d ~
~
U U ~ L
.
U U~
O
.ri~ 1~ C d U1 O ~
. ~'' ~ 0 V ' ~
~ ~ 00 3 O c f y tl! 7 d .. .~ N
d O a ~ N d0 O L.
cUd .t ~w C C 6 U ~ U ~ ' O ~ 1~ ~ 3~
> ~
~C O ~ .
N ~ ~ t1 ~ O
~ 0 . U
r V > ~ t/7d ~.
., , 3 2 :;;: , , , ~ , ~13582'~
As is apparent from these examples, the coated paperes with use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle. In Comparative examples 25~ 30, unevenness of coating surface occured and stripy print mottle specific to the transfer roll coating was observed.
3. -3 . . ; , ':: .
lt1 N
N v !~
N
d y 0 N
~ V
N ~ M
"
N ~
O ~., N
O
N
O ~
O
O U O
H
> N
~
.-r O
r-1 Gl .
~' ~ ~ ~ E
.-r U
~- v0 ~ X
N lf~
O
O ~ ~ ~' O
O
.N
O
d ~
~
U U ~ L
.
U U~
O
.ri~ 1~ C d U1 O ~
. ~'' ~ 0 V ' ~
~ ~ 00 3 O c f y tl! 7 d .. .~ N
d O a ~ N d0 O L.
cUd .t ~w C C 6 U ~ U ~ ' O ~ 1~ ~ 3~
> ~
~C O ~ .
N ~ ~ t1 ~ O
~ 0 . U
r V > ~ t/7d ~.
., , 3 2 :;;: , , , ~ , ~13582'~
As is apparent from these examples, the coated paperes with use of the transfer roll coating color according to the present invention were excellent in printability, particularly against print mottle. In Comparative examples 25~ 30, unevenness of coating surface occured and stripy print mottle specific to the transfer roll coating was observed.
3. -3 . . ; , ':: .
Claims (5)
1. A transfer roll coating color composed mainly of pigments and adhesives, the transfer roll coating color wherein the adhesives are starch type adhesives having a coefficient of viscosity in the range of 580 cps or over and not exceeding 3,000 cps when measured under the following conditions:
viscometer: B-type viscometer (Brookfield.TM.
viscometer);
#4 spindle: 60 rpm;
temperature: 50°C;
concentration of solid materials: 30 wt% or higher;
and the pigments have 10 or lower average aspect ratio and 1,500 cps or lower coefficient of viscosity when measured under the following conditions:
viscometer: B-type viscometer (Brookfield.TM.
viscometer);
#4 spindle: 60 rpm; and concentration of solid materials: 58 wt% or higher.
viscometer: B-type viscometer (Brookfield.TM.
viscometer);
#4 spindle: 60 rpm;
temperature: 50°C;
concentration of solid materials: 30 wt% or higher;
and the pigments have 10 or lower average aspect ratio and 1,500 cps or lower coefficient of viscosity when measured under the following conditions:
viscometer: B-type viscometer (Brookfield.TM.
viscometer);
#4 spindle: 60 rpm; and concentration of solid materials: 58 wt% or higher.
2. A transfer roll coating color of claim 1, wherein the pigments contain 30 wt% or higher calcium carbonate having 5 or lower aspect ratio and 2 µm or lower in average particle size.
3. A printing paper wherein 5 g/m2 or more of the coating color of claim 1 or 2 is coated on each surface of a raw paper by a transfer roll coater.
4. A method of making a coated printing paper comprising the steps of:
preparing a raw paper;
preparing a color composed of a pigment and a starch adhesive having the following properties and a small amount of additives as necessary with 58 weight % or higher in solid components, and 1,500 cps or less in coefficient of viscosity when measured at 60 rpm by using a No.4 rotor of a Brookfield.TM. viscometer; the pigment:
or lower in average aspect ratio and containing calcium carbonate having 5 or lower in average aspect ratio and 3 µm or less in average particle diameter as 30 weight % or higher of the total pigment, the starch adhesive:
3,000 cps or less in coefficient of viscosity when measured at 30 weight % or lower in concentration, at a temperature of 50°C and at 60 rpm by using a No.4 rotor of a Brookfield.TM. viscosimeter, and coating the color on both surfaces of the raw paper with 5 g/m2 or more in solid components per each surface by a transfer roll coater.
preparing a raw paper;
preparing a color composed of a pigment and a starch adhesive having the following properties and a small amount of additives as necessary with 58 weight % or higher in solid components, and 1,500 cps or less in coefficient of viscosity when measured at 60 rpm by using a No.4 rotor of a Brookfield.TM. viscometer; the pigment:
or lower in average aspect ratio and containing calcium carbonate having 5 or lower in average aspect ratio and 3 µm or less in average particle diameter as 30 weight % or higher of the total pigment, the starch adhesive:
3,000 cps or less in coefficient of viscosity when measured at 30 weight % or lower in concentration, at a temperature of 50°C and at 60 rpm by using a No.4 rotor of a Brookfield.TM. viscosimeter, and coating the color on both surfaces of the raw paper with 5 g/m2 or more in solid components per each surface by a transfer roll coater.
5. A method of making a coated paper of claim 4 wherein the pigments contain 30 wt% or higher calcium carbonate having 5 or lower aspect ratio and 2 µm or lower in average particle size.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP286313/1993 | 1993-11-16 | ||
| JP28631393 | 1993-11-16 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2135827A1 CA2135827A1 (en) | 1995-05-17 |
| CA2135827C true CA2135827C (en) | 2006-08-01 |
Family
ID=17702771
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002135827A Expired - Fee Related CA2135827C (en) | 1993-11-16 | 1994-11-15 | Transfer roll coating color and a coated paper |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR100362727B1 (en) |
| CA (1) | CA2135827C (en) |
-
1994
- 1994-11-11 KR KR1019940029659A patent/KR100362727B1/en not_active IP Right Cessation
- 1994-11-15 CA CA002135827A patent/CA2135827C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| KR950014246A (en) | 1995-06-15 |
| KR100362727B1 (en) | 2003-02-05 |
| CA2135827A1 (en) | 1995-05-17 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed | ||
| MKLA | Lapsed |
Effective date: 20121115 |