JP2010281015A - Patterned paper for postcard - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a patterned paper for postcards, having excellent design flexibility and offset printability. <P>SOLUTION: The patterned paper has a pattern formed by randomly scattering white flocks on a colored substrate obtained by a mixed paper-making process of a colored pulp and the white flock, wherein the patterned paper has a density of 0.75-0.85 g/cm<SP>3</SP>, an Oken type smoothness of ≥20 sec and a white flock content of 1-10 mass%, and ratio of white pigments to the sum of the white pulp and the white pigments in the white flock is 10-80 mass%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a postcard paper excellent in design, and more particularly to a postcard pattern paper having offset printing suitability.

In recent years, variations of New Year's cards with New Year's cards have been increasing, and the New Year's greeting cards that are lightly colored, and character New Year's cards with Disney characters printed on the market, are gaining popularity. Postcards for postcards (government-made postcards) are required to have offset printability on at least one side in order to perform offset printing such as the postal code field, fee stamp, and New Year lottery number.

  On the other hand, papers with various design properties are distributed in the market, and are widely used for applications such as pamphlets and catalogs, book covers, covers, flips, and strips. In particular, in the field called fancy paper or fine paper, pattern paper with a pattern on paper has been widely distributed. For example, a method of making a paper by mixing pre-colored fibers with a white stock is “hairy”. It is called “dyed” and has been known for a long time. In addition, as a method of mixing foreign matters other than colored fibers, a method of mixing colored rice bran (Patent Document 1), a method of mixing colored water-soluble polymer (Patent Document 2), a dye is added to soybean protein, etc. For example, a method of mixing dyed floc agglomerated by a method (Patent Document 3), a method of mixing papyrus digested pulp (Patent Document 4), and the like have been proposed. Furthermore, a method of adding a substance capable of flocking the pulp upstream of the paper machine inlet and spraying the dye solution and / or pigment dispersion on the water surface during initial dehydration (Patent Document 5), wetness on the wire of the paper machine A method of supplying a colorant together with a water-soluble polymer to paper or slurry and reacting with a cationic substance in the slurry to partially color (Patent Document 6) has also been proposed. Both of these are methods for forming a dark pattern on a light-colored background, but there is also a method for forming a light-colored pattern on a dark-colored background. For example, white floc obtained by agglomerating white pulp and white pigment is used. Examples include pattern paper mixed with colored pulp (for example, Feather Waltz / Oji Specialty Paper Co., Ltd.).

Pattern paper mixed with white floc and colored pulp is a pattern in which white floc is scattered on a colored base, as if petals and snow flutter, and is suitable as a New Year's postcard paper due to its texture. . However, what is available in the current market is not suitable for offset printing, and if there is a small amount of printing, there is no problem, but it is not suitable for applications that require large-scale printing such as postcards, and this is improved. No attempt was made to try.

63-78099 JP 63-219698 A JP-A 63-295798 JP 10-183489 A JP-A-8-74199 JP 7-279100 A

  The subject of this invention is providing the pattern paper for postcards which was excellent in the designability by providing offset printing aptitude to the pattern paper which mixed white flock with the colored pulp.

As a result of intensive studies on the above problems, the present inventors have achieved the object by the following invention.
(1) A pattern paper in which a pattern in which white flocs are randomly scattered is formed on a base colored by mixing white flocs with colored pulp, and has a density of 0.75 to 0.90 g / cm ³ , king The polishing smoothness is 20 seconds or more, the white floc content is 1 to 10% by mass, the white floc contains white pulp and white pigment, and the total mass of the white pulp and white pigment in the white floc Pattern paper for postcards with a white pigment occupancy of 10 to 80% by mass.
(2) The pattern paper for postcards according to the above (1), wherein the occupancy ratio of the white pigment in the total mass of the white pulp and the white pigment in the white floc is 10 to 40% by mass.
(3) The pattern paper for postcards as described in (1) or (2) above, wherein the white pulp in the white floc is LBKP.
(4) The pattern paper for postcards according to the above (1) to (3), wherein the white pigment in the white floc is titanium dioxide.
(5) The pattern for postcards as described in (1) to (4) above, wherein the white floc is obtained by adding a cationic flocculant to a slurry comprising white pulp, a white pigment and an anionic water-soluble polymer. paper.
(6) The pattern paper for postcards according to the above (1) to (5), wherein an ink receiving layer is provided on at least one side.

  The postcard pattern paper of the present invention is suitable for greeting cards such as New Year's cards because of its texture. In addition, since it has offset printing suitability, it can also be used as a postcard paper requiring mass printing.

Pattern paper for postcards of the present invention (hereinafter also simply referred to as “pattern paper”) is a pattern in which white flocks are randomly scattered on a colored base by mixing white flock and colored pulp, The density needs to be 0.75 to 0.90 g / cm ³ . If the density is less than 0.75 g / cm ³ , the bonding between the colored pulp fibers is insufficient, and picking tends to occur during offset printing, which is not preferable. On the other hand, it is not preferable to obtain a material having a density exceeding 0.90 g / cm ³ because white flocs frequently become transparent. In addition, the white floc in this invention points out the aggregate which has a white pulp and a white pigment as an essential component, and points out what is not easily fibrillated even if it dilutes and stirs. In general, pulp fibers form a flock in the form of lumps at a high concentration, but are mostly defibrated when diluted and stirred.

The patterned paper of the present invention needs to have Oken smoothness of 20 seconds or more. If it is less than 20 seconds, the smoothness is poor and the printed finish is insufficient. Although the upper limit of smoothness is not particularly provided, it is usually 100 seconds or less.

In this invention, it is necessary to make the white floc content rate in a pattern paper into 1-10 mass%. If the white floc content is less than 1%, the pattern is sparse and the texture is poor. On the other hand, if it exceeds 10% by mass, there are too many patterns and the texture is inferior, and picking is liable to occur during offset printing. More preferably, it is 3-7 mass%.

    The white floc in the pattern paper of the present invention contains white pulp and white pigment. Examples of the white pulp include bleached wood pulp, non-wood pulp, and synthetic pulp that are generally used in the industry, and those having a whiteness of 70% or more are preferable, and more preferably, the whiteness is 80% or more. is there. Among them, LBKP (hardwood bleached kraft pulp) or NBKP (softwood bleached kraft pulp) is preferable because it is inexpensive and easily available. However, NBKP has a long fiber length and tends to form a huge flock, so LBKP is used. Is particularly preferred. The freeness of white pulp is not particularly limited, and those having a CSF (Canadian Standard Freeness) of about 100 to 750 ml can be used.

As the white pigment, white pigments generally used in the industry can be widely used, and examples thereof include heavy calcium carbonate, light calcium carbonate, magnesium carbonate, kaolin, calcium sulfate, barium sulfate, titanium dioxide, and zinc oxide. Of these, titanium dioxide having high whiteness and opacity is particularly preferable.

In the present invention, it is necessary that the occupation ratio of the white pigment in the total mass of the white pulp and the white pigment in the white floc is 10 to 80% by mass. If the white pigment occupancy is less than 10% by mass, the opacity of the white floc is low, and the contrast with the ground becomes insufficient due to the effect of the colored pulp under the floc, and the pattern is not easily recognized. On the other hand, if the white pigment occupancy exceeds 80% by mass, the flocs after drying are not flexible, and therefore, it is not preferable because the flocs tend to break or fall off during cutting. In addition, as the white pigment occupancy increases, picking tends to occur more easily at the portion where the white floc is incorporated during offset printing. For the above reasons, the white pigment occupancy is more preferably 10 to 40% by mass.

The method for preparing the white floc of the present invention is not particularly limited, and for example, a method of adding a flocculant to the mixed slurry of white pulp and white pigment and aggregating it can be exemplified. A method is preferred in which a cationic flocculant is added to a mixed slurry of white pulp, white pigment and anionic water-soluble polymer for aggregation.

Examples of the anionic water-soluble polymer component include anionic cellulose derivatives such as CMC (carboxymethylcellulose), anionic starch derivatives such as oxidized starch and phosphated starch, anionic PAM (polyacrylamide), and sodium polyacrylate. , Sodium alginate, anion-modified PVA (polyvinyl alcohol), and the like. Examples of the cationic flocculant include a sulfate band, polyaluminum chloride, cationic PAM, and polyethyleneimine. Among these, a combination of CMC and a sulfate band is preferable from the viewpoint of stability of flock and availability.

The amount of anionic water-soluble polymer and cationic flocculant added cannot be unconditionally because the action varies depending on the type of anionic water-soluble polymer and cationic flocculant selected, but usually white pulp and white pigment The anionic water-soluble polymer may be added in an amount of 10 to 100 parts by mass and the cationic flocculant in an amount of 1 to 50 parts by mass with respect to 100 parts by mass in total.

The pattern paper of the present invention can be obtained by making a mixed slurry of the white floc and colored pulp, but if too much floc is made, it is crushed by a calendar to become transparent, or in a severe case, a paper making process Therefore, it is preferable to remove a huge floc before or after mixing with the colored pulp. An example of a method for removing a huge floc is a method of passing a round hole screen having an opening diameter of about 3 mm. The colored pulp needs to be passed through a screening process such as a screen or a cleaner before mixing with the white floc. This is because the white floc is removed after mixing with the white floc.

The colored pulp is preferably one in which white pulp is dyed with a dye because the color can be freely selected. LBKP or NBKP is suitable as the white pulp for the colored pulp, and it can be used alone or as a mixture, and the freeness is preferably about 300 to 500 ml CSF. The kind of the dye is not particularly limited, and a dye, a colored pigment, a fixing agent and the like generally used in the industry can be used in combination. The white pulp may be dyed in any step as long as it is before mixing with the white floc, and a colored pulp sheet that has been dyed in advance may be separated again and used. As the hue of the colored pulp becomes darker, the contrast with the white floc is obtained, and the visibility of the pattern is improved. However, since it impedes reading of the zip code and the like, it is appropriately adjusted within a practical range.

The paper machine for making the pattern paper of the present invention is not particularly limited, and known paper machines such as a long net machine, a short net machine, a circular net machine, and an inclined wire machine can be widely used. The desired density and smoothness are adjusted by calendar processing. It is of course possible to add auxiliary agents such as fillers, internal paper strength agents, sizing agents, antifoaming agents, lubricants, yield improvers and the like to the mixed slurry of white floc and colored pulp as necessary.

The patterned paper of the present invention is preferably coated with a surface paper strength agent on at least one side (address side). The method for applying the surface paper strength agent is not particularly limited, and known application methods such as a size press coater, a gate roll coater, an air knife coater, a bar coater, a blade coater, a curtain coater, a die coater, and a kiss coater can be exemplified. It can be either machine or off-machine. Examples of the surface paper strength agent include PVA, starch, PAM and the like that are generally used in the art, but a completely saponified PVA is particularly preferable because of its excellent film strength. If the coating amount is too small, the effect of improving the surface strength is insufficient. If the coating amount is too large, the ink absorption is delayed and the set-off tends to occur. Therefore, about 0.5 to 2.0 g / m ² per side, Preferably it is 0.7-1.5 g / m < ² >.

More preferably, the patterned paper of the present invention is provided with an ink receiving layer for inkjet on one side (communication side). The ink receiving layer is not particularly limited, and a known ink receiving layer can be widely used. Examples thereof include an ink receiving layer coated with a paint in which synthetic silica, PVA, a cationic resin, or the like is mixed and dispersed in water. The coating amount is not particularly limited, but if the coating amount is too small, the effect of improving the inkjet suitability is insufficient, and if it is too large, the pattern is concealed, and preferably 1 to 10 g / m ² . Preferably it is 3-7 g / m < ² >. If emphasis is placed on the transparency of the pattern, a swollen ink receiving layer made of a transparent resin may be provided. Examples of the transparent resin include gelatin, PVP (polyvinylpyrrolidone), and PVA.

  The method of providing the ink receiving layer is not particularly limited, and a method of coating by a known coating method such as an air knife coater, roll coater, bar coater, blade coater, curtain coater, die coater, cast coater, film, etc. The method etc. which bond the resin which turned into can be illustrated. Of course, it is also possible to adjust the density and smoothness to a desired level by calendaring on or off machine after coating or after bonding.

  Although offset printing such as a postal code column is performed on one side (address side) of the pattern paper of the present invention, when the smoothness differs between the front and back of the pattern paper, it is preferable to print on the surface with high smoothness. However, when the ink receiving layer is provided on one side, printing is performed on the surface not provided with the ink receiving layer.

<Example>
Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, the numerical values indicating the composition, concentration, etc. are all values based on the solid content or the mass of the active ingredient. Unless otherwise specified, the papers made were conditioned according to JIS P8111 and then subjected to measurements and tests. First, a pattern paper evaluation method will be described.

<Smoothness>
JAPAN TAPPI Paper Pulp Test Method No. Based on 5-2: 2000, the Oken type smoothness of the pattern paper was measured. The measurement was performed at 5 points on each of the felt surface and the wire surface, and the higher average value of the 5 points was defined as the smoothness.

<Print strength>
Using an RI tester (manufactured by Ishikawajima Sangyo Machinery Co., Ltd.), 1.5 cc of printing ink (manufactured by T & K / TOKA Co., Ltd.) was solidly printed on the surface having high smoothness, and visually evaluated according to the following criteria.
A: There is no picking at all.
○: Slight picking, but no problem in practical use.
Δ: Picking and inferior versatility.
X: There are many picking and there is a problem in practical use.

<Ink fillability>
Using an RI tester (manufactured by Ishikawajima Sangyo Machinery Co., Ltd.), 0.5 cc of printing ink (TK high unity ink MZ / manufactured by Toyo Ink Co., Ltd.) was solidly printed on the high smoothness surface and visually evaluated according to the following criteria. .
(Double-circle): There is no unevenness of the meat and is good.
○: There is slight unevenness of the fleshing, but there is no practical problem.
Δ: There is uneven unevenness of the flesh and inferior versatility.
X: Unevenness in meat is severe and there is a problem in practical use.

<Appearance>
The visibility of the pattern, the number, and the transparency of the flock were visually evaluated according to the following criteria.
○: Good.
Δ: Slightly defective
X: It is bad.

Next, the preparation method of the paper stock used in the examples and comparative examples is shown.
<Preparation of colored pulp>
LBKP (whiteness 85%, freeness 590 ml CSF) was thrown into water to break up and beaten to adjust the freeness to 400 ml CSF. To this pulp slurry, 100 parts of dry dry pulp, 0.026 each of violet BBN (manufactured by LANXESS), Scarlet 4BS (manufactured by Toa Kasei) and yellow A (manufactured by Toa Kasei) Parts, 0.0060 parts, 0.0095 parts, 0.5 parts Polystron 1250 (amphoteric PAM / Arakawa Chemical Industries) as a paper strength agent, Size Pine N-111 (Rosin emulsion sizing agent / Arakawa Chemical) as a sizing agent 0.25 part of Kogyo Co., Ltd. and 6 parts of talc as a filler were added, and 0.16 part of sulfuric acid band (as Al2O3 equivalent) was added to obtain a colored pulp slurry.

<Preparation of white frock>
LBKP (85% whiteness, freeness 590 ml CSF) and CMC (CMC Daicel 1153 / manufactured by Daicel Chemical Industries, Ltd.) are added to water and stirred to dissolve CMC, then titanium dioxide is added and stirred to mix A slurry was obtained. To 100 parts of the solid content of the mixed slurry, 10 parts of a sulfuric acid band (in terms of Al2O3) was added and aggregated to obtain white floc slurries A to E. When the obtained slurry was filtered with an 80 mesh wire mesh, the filtrate was colorless and transparent, and only a very small amount of pulp fiber was observed. Therefore, it was judged that the ratio of LBKP to titanium dioxide in the white floc was almost the same as the blending ratio. did. Table 1 shows the solid content ratios of LBKP, CMC, and titanium dioxide, and the white pigment occupancy ratio (based on the total mass of the white pulp and the white pigment).

<Example 1>
The colored pulp slurry and white floc slurry C were mixed at a solid content ratio of 95: 5, and the paper was made with a long mesh multi-cylinder paper machine. When making paper, apply PVA (Denkapoval K-17FE / manufactured by Denki Kagaku Kogyo Co., Ltd.) with a size press so that the amount of adhesion after drying is 1.5 g / m ^{2 on} both sides. A patterned paper having a weight of 190 g / m ² and a density of 0.83 g / cm ³ after processing was obtained.

<Example 2>
Pattern paper was obtained in the same manner as in Example 1 except that white flock B was used instead of white flock slurry C.

<Example 3>
Pattern paper was obtained in the same manner as in Example 1 except that white floc D was used in place of white floc slurry C.

<Comparative Example 1>
Pattern paper was obtained in the same manner as in Example 1 except that white flock A was used in place of white flock slurry C.

<Comparative example 2>
Pattern paper was obtained in the same manner as in Example 1 except that white floc E was used instead of white floc slurry C.

<Comparative Example 3>
A pattern paper was obtained in the same manner as in Example 1 except that the mixing ratio of the colored pulp slurry and the white floc slurry C was 99.5: 0.5.

<Comparative example 4>
A pattern paper was obtained in the same manner as in Example 1 except that the mixing ratio of the colored pulp slurry and the white floc slurry C was 85:15.

<Comparative Example 5>
A pattern paper was obtained in the same manner as in Example 1 except that the calender treatment was strengthened to obtain a density of 0.95 g / cm ³ .

<Comparative Example 6>
Pattern paper was obtained in the same manner as in Example 1 except that the calender treatment was reduced to a density of 0.70 g / cm ³ .

<Comparative Example 7>
A commercially available pattern paper (Feather Waltz Sakura / Oji Specialty Paper Co., Ltd.) was used for evaluation.

    Table 2 shows the evaluation results of the pattern papers of Examples and Comparative Examples. The patterned paper of the present invention has a good appearance and is suitable for offset printing, and can be used for mass printing applications such as postcards.

Claims (6)

A pattern paper in which a pattern in which white flocs are randomly scattered is formed on a colored base by mixing white flocs with colored pulp, and has a density of 0.75 to 0.90 g / cm ³ , Oken type smoothness The white floc content is 1 to 10% by mass, the white floc contains white pulp and a white pigment, and the white pigment in the total mass of the white pulp and the white pigment in the white floc Pattern paper for postcards, characterized in that the occupation ratio is 10 to 80% by mass. The pattern paper for postcards according to claim 1, wherein the occupancy ratio of the white pigment in the total mass of the white pulp and the white pigment in the white floc is 10 to 40% by mass. 3. The pattern paper for postcard according to claim 1, wherein the white pulp in the white floc is LBKP. 4. The pattern paper for postcards according to claim 1, wherein the white pigment in the white floc is titanium dioxide. 5. The pattern paper for postcards according to claim 1, wherein the white floc is obtained by adding a cationic flocculant to a slurry composed of white pulp, a white pigment, and an anionic water-soluble polymer. . The postcard pattern paper according to any one of claims 1 to 5, wherein an ink receiving layer is provided on at least one side.