JP2006159655A - False adhesive paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a conveyance trouble from occurring in an electron photography system recording device. <P>SOLUTION: This false adhesive paper is pretreated based on JIS P 8111, and is characterized in that the measured surface electric resistance value is 6×10<SP>9</SP>to 1×10<SP>12</SP>, the coefficient of surface friction is 0.1 to 0.4 and the residual curl value is not more than 20 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pseudo-adhesive paper that has a function of being primarily bonded but easily peeled off when necessary. In particular, the present invention relates to pseudo-adhesive paper for printing / printing characters / graphics on the surface of the pseudo-adhesive layer using an electrophotographic recording apparatus.

  Pseudo-adhesive paper is, for example, folded with the pseudo-adhesive layer surface on which various information such as confidential information is printed / printed as the inner surface, and the superimposed surface is pseudo-adhered to conceal the information and sent by mail. It is used for postcard systems that read concealment information. For example, in such a postcard system, when printing / printing on pseudo-adhesive paper, frame printing or pattern printing (also called form printing) other than variable information represented by confidential information or personal information is performed at high speed. This is often done by offset printing, which enables high-contrast printing and printing. For recording variable information that differs for each postcard represented by confidential information, personal information, etc., an electrophotographic system represented by a laser printer or NIP printer is used. Often performed by a recording device. Therefore, in pseudo-adhesive paper, these form printability and electrophotographic recordability are important. In particular, maintaining good paper transportability in various devices is an important point indispensable for improving work efficiency.

Among these devices used for printing, printing or pressure bonding of pseudo-adhesive paper, the electrophotographic recording device heat-melts fine toner with a heat roll, flash, etc., and transfers it to the paper for printing.・ Use a configuration to perform printing.
JP 2003-105287 A JP2003-072265 JP2002-023643

  Therefore, the paper is heated by the recording device, the moisture content of the paper changes, and the paper is likely to curl. However, with the recent increase in the speed of the electrophotographic recording device, the pseudo-adhesive paper is discharged in a heated state. The harmful effects caused by this are becoming prominent. That is, when printing pseudo-adhesive paper with an electrophotographic recording apparatus, the pseudo-adhesive paper discharged after printing can be temporarily stored in a cut sheet laminated state, a folded laminated state, or a winding roll state. However, curling occurs due to a change in the moisture content of the paper, and there are many situations in which the paper transportability and the paper stack shape deteriorate.

  Therefore, a main problem of the present invention is to prevent a curling trouble associated with a change in paper moisture content in a pseudo-adhesive paper of a pre-glue method.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
On both sides of the base paper, there is a pseudo-adhesive layer that can be pseudo-bonded in a peelable manner when given conditions are not adhered under normal conditions, and characters and figures are printed and printed on the surface of the pseudo-adhesive layer. A so-called pre-glue type pseudo-adhesive paper,
Pretreated according to JIS P 8111, measured surface electrical resistance value is 6 × 10 ⁹ to 1 × 10 ¹² , surface friction coefficient is 0.1 to 0.4, and the following residual curl value is 20 mm or less. A pseudo-adhesive paper characterized by that.
(Residual curl value)
The residual curl value is calculated according to the following (A) to (F).
(A) The size of the paper sample is 100 mm square.
(B) The center of the diagonal line of the sample is supported at one point.
(C) Ambient humidity in a supported state at 20 ° C. is 50% RH → 65% RH → 80% RH → 65% RH → 50% RH → 35% RH → 20% RH → 35% RH → Change continuously every 4 hours in the order of 50% RH.
(D) After the paper sample has reached equilibrium moisture at the final 50% RH, the paper sample is placed on a horizontal table with the curl convex portion facing downward.
(E) The perpendicular distance from each vertex of the four corners of the paper sample to the horizontal base is measured.
(F) Let the average value of the measured distance be a residual curl value.

<Invention of Claim 2>
The pseudo-adhesive paper according to claim 1, wherein the absolute value of the difference in fiber compounding ratio between the front and back surfaces is 0.4 or less.

<Invention of Claim 3>
The pseudo-adhesive paper according to claim 1 or 2, wherein a difference in coating amount of the pseudo-adhesive on the front and back surfaces is 5 g / m ² or less.

(Function and effect)
According to the present invention, the curling behavior when the environmental conditions change is defined in addition to the surface electrical resistance value and the surface friction coefficient, so that the transportability when printing / printing is performed in an electrophotographic recording apparatus such as a so-called laser printer. Is improved, paper conveyance troubles are prevented, and printing and printing work efficiency is improved.

Next, embodiments of the present invention will be described in detail below.
The pseudo-adhesive paper of the present invention has on both sides of the base paper a pseudo-adhesive layer that is detachably pseudo-adhered when given conditions without being bonded in a normal state. It is a so-called paste-type pseudo-adhesive paper used by printing / printing characters / graphics, and has a surface electrical resistance value of 6 × 10 ⁹ to 1 measured in a preprocessed state based on JIS P 8111. × 10 ¹² , the surface friction coefficient is 0.1 to 0.4, and the residual curl value is 20 mm or less.

  As the base paper, either recycled paper made from used paper or non-recycled paper made from virgin pulp can be used. A preferable base paper is a high-quality paper substantially made of chemical pulp as a raw material pulp, and in particular, a paper using only virgin pulp as a raw material is desirable. The kind of pulp used as the raw material for the base paper is not particularly limited, and conventionally known pulp used for the production of fine paper and the like can be used. Specific examples include sulfite pulp (SP), soda pulp (AP), kraft pulp (KP) such as LBKP and NBKP, chemi-ground pulp (CGP), semi-chemical pulp (SCP), bleached pulp crushed under pressure (BPGW). The raw material pulp is used after bleaching if necessary. In that case, it is desirable to bleach by the bleaching method which does not use chlorine. That is, when bleached pulp is used, it is desirable to use TCF pulp or ECF pulp.

  The base paper can be made by a general paper making technique of western paper. That is, after the raw pulp is made into a slurry, it may be made using a paper machine such as a long paper machine, a round paper machine, a twin wire type paper machine, or a multilayer paper machine.

  It is preferable to add a filler to the base paper within a range necessary for the pseudo-adhesive paper. Fillers include clay, calcite precipitated calcium carbonate forming primary or secondary aggregates, aragonite precipitated calcium carbonate forming secondary aggregates, calcium carbonate, silica, synthetic fine particle silica, Amino surface modified silica, wax surface treated silica, spherical silica, normal calcium, metal oxides such as zinc, magnesium, aluminum or titanium, inorganic pigments such as hydroxide, carbonate, silicate, or the like Organic pigments such as polyethylene pigments used in mixtures, coated paper, etc., urea resin particles, polystyrene resin particles, styrene / acrylic copolymer particles, urea formalin resin particles, micro hollow particles, porous particles, etc. Pigments, or mixtures thereof.

  On the other hand, the pseudo-adhesive layer is a non-peelable adhesive (hereinafter referred to as “adhesive base”) containing a filler having non-affinity in the adhesive base to give a pseudo-adhesive force. Can be applied to the base paper. The mixing ratio of the adhesive base and the filler may be a general mixing ratio of a kind of pseudo-adhesive formed by adding the filler to the adhesive base. Specifically, the amount of the filler is about 5 to 500 parts by weight with respect to 100 parts by weight of the adhesive base. In the present invention, a particularly preferable range is 10 to 300 parts by weight of the filler with respect to 100 parts by weight of the adhesive base.

  The adhesive base may be arbitrarily selected from those conventionally used for usual adhesive bases such as latex, natural rubber, synthetic rubber, etc., but natural rubber is particularly sulfur-free vulcanized. Natural rubber latex mixed with methyl methacrylate, natural rubber latex obtained by graft copolymerization of methyl methacrylate with natural rubber, acrylic modified rubber latex, rubber latex and protective colloidal acrylic copolymer emulsion A mixture is suitable in terms of blocking resistance, deterioration with time, and the like.

  The filler is not particularly limited, and a filler used in the production of a conventionally known pseudo adhesive may be used. Preferably, it contains an inorganic pigment having an oil absorption of 80 to 400 mL / 100 g based on JIS K 5101 because it is excellent in printing and printing with an ink jet recording apparatus. If the oil absorption is less than 80 mL / 100 g, the absorbability of the inkjet ink tends to be insufficient. That is, the printability and printability of the ink jet recording apparatus are likely to be inferior. On the other hand, when it is 400 mL / 100 g or more, the coating layer strength is lowered and the pseudo adhesive layer is easily peeled off. The blending ratio of the inorganic pigment in the pseudo-adhesive is 10 to 70% by weight, preferably 20 to 50% by weight. If it is less than 10% by weight, the ink-jet ink absorbability tends to be insufficient. Specifically, the inorganic pigment includes calcite-based precipitated calcium carbonate (Shiraishi Kogyo Co., Ltd .: PC, Callite KT) that forms primary or secondary aggregates, and aragonite that forms secondary aggregates. Preferred are system precipitated calcium carbonate (Shiraishi Kogyo Co., Ltd .: Callite SA), heavy calcium carbonate, calcined kaolin, synthetic silica and the like. These may be used alone or two or more of them may be mixed. In addition, styrene beads, synthetic fine particle silica, amino surface-modified silica, wax surface-treated silica, spherical silica, ordinary calcium, oxides of metals such as zinc, magnesium, aluminum or titanium, hydroxides, carbonates, Silicate or a mixture thereof may be contained.

  In the present invention, as other auxiliary agents incorporated in the pseudo-adhesive, lubricants, printability improvers, antioxidants, ultraviolet absorbers, conductive agents, fluorescent dyes, colored dyes, preservatives, humectants, inkjets An ink fixing agent or the like can be blended as necessary.

The application of the pseudo-adhesive can be performed by a coating method using a conventionally known coating machine. In the present invention, the coating machine is preferably applied using an air knife coater, blade coater, rod metering coater, curtain coater, or roll coater, and in particular, a colored pseudo-adhesive paint is applied. In some cases, a curtain coater that can be applied more uniformly is desirable. The coating amount is desirably 3 to 15 g / m ² . If it is less than 3 g / m ² , the desired adhesive force cannot be obtained and unintended peeling tends to occur. If it exceeds 15 g / m ² , the adhesive strength becomes too strong to make it difficult to peel again, and glue will adhere to the coating roll at the time of coating, leading to operational and quality problems.

  After applying the pseudo-adhesive on the base paper, it is desirable to smooth the coated surface, and the smoothing process may be performed by a normal calendar process. Calendar processing can be performed with a coater and a series of calendars (on-machine calendar), or with a coater and a series of separate calendars (off-machine calendar). The type of is not particularly limited. Conventionally known calendars such as a calendar provided with a metal roll and an elastic roll, a calendar obtained by combining metal rolls, and the like can be used.

  The residual curl value is calculated by measuring as follows. First, a paper sample cut into a 100 mm square is supported at one point on the center of the diagonal line, and in this supported state, the ambient humidity is 50% RH → 65% RH → 80% RH → 65% RH → 50 in an environment of 20 ° C. % RH → 35% RH → 20% RH → 35% RH → 50% RH In this order, the paper sample is curled after the paper sample has reached equilibrium moisture at the final 50% RH. It is placed on a horizontal table so that the convex portions are on the bottom, and the perpendicular distances from the four corners of the paper sample to the horizontal table are measured, and the average value of the measured distances is calculated.

The residual curl value of the pseudo-adhesive paper of the present invention is 20 mm or less. In order to reduce the residual curl value to 20 mm or less, adjustment of the coating amount of the base paper and / or pseudo adhesive layer and the base paper In this stage, the fiber orientation angle can be adjusted by adjusting the inlet lip angle or the inlet discharge amount. Here, the fiber orientation angle according to the present invention refers to an angle formed by the reference direction and the fiber, and specifically, the MD direction (the paper traveling direction on the paper machine and the paper length direction). It is a value indicated by the angle from. The fiber orientation angle can be measured by, for example, an optical orientation tester (FOT) manufactured by Toyo Seiki Seisakusho Co., Ltd. Specifically, laser light having a wavelength of 685 nm is irradiated at a constant angle with respect to the paper surface, and the fiber orientation angle is measured from the change in the intensity of reflected light. As described above, the fiber orientation angle is obtained by quantitatively measuring the direction of the length direction of the fiber raw material in the flow direction and the width direction of the base paper and quantifying the ratio. When the ratio of the direction (vertical) and the width direction (horizontal) is 1-2, the residual curl value is easily within the range of the value of the present invention. Furthermore, the curl value can also be adjusted by providing a difference in the amount of application of the pseudo adhesive on the front and back surfaces. However, in the case where the coating amount of the adhesive layer is different between the front side and the back side, the difference amount is preferably 5 g / m ² or less. The problem that the function as a pseudo-adhesive paper is impaired appears. Note that, in the method of providing the difference in coating amount and the method of adjusting the fiber orientation angle of the base paper, the adjustment of the fiber orientation angle of the base paper has a higher influence on the residual curl value of the pseudo-adhesive paper. The residual curl value is adjusted in consideration of the above.

On the other hand, the pseudo-adhesive paper of the present invention has a surface electrical resistance value of 6 × 10 ⁹ to 1 × 10 ¹² . Preferably, it is 1.0 × 10 ^{10 to} 1.0 × 10 ¹¹ . If it is less than 6 × 10 ⁹ , toner transfer failure occurs, and if it exceeds 1 × 10 ¹² , double feed, misfeed, and toner scattering occur. The surface electrical resistance is measured by setting a paper sample pretreated based on JIS P 8111 on a surface electrical resistance measuring machine (model number: TR-8601) manufactured by TAKEDA RIKEN. The surface electrical resistance of the pseudo-adhesive paper can be adjusted by adding a conductive material in the base paper, preferably in the pseudo-adhesive. For example, an appropriate amount of a conductive agent may be added to a papermaking raw material or a pseudo adhesive. Conductive agents include inorganic electrolytes such as sodium sulfate, sodium carbonate, lithium carbonate, sodium metasilicate, sodium tripolyphosphate and sodium metaphosphate; anionic interfaces such as sulfonate, sulfate ester, carboxylate and phosphate Activating agents; Cationic surfactants such as quaternary ammonium salts; Nonionic surfactants such as polyethylene glycol, polypropylene glycol, glycerin, and sorbit; and conductive agents such as amphoteric surfactants and polymer electrolytes It is done. If sodium sulfate is used as the conductive agent, the surface electrical resistance value of the present invention can be adjusted by adding about 0.5 to 2.5 parts by weight with respect to 100 parts by weight of the pseudo adhesive in the pseudo adhesive. can do.

  On the other hand, the pseudo-adhesive paper of the present invention has a surface friction coefficient of 0.1 to 0.4. Preferably, it is 0.2-0.3. If it is less than 0.1, the friction with the paper feed roller is reduced and the paper does not feed, and if it exceeds 0.4, the paper feed failure due to the large friction between the paper in the laminated state, The incidence of double feed increases.

  The surface friction coefficient is measured as follows. The paper sample has a size of 100 mm square and is pretreated according to JIS P 8111. Next, a SUS flat plate is placed and fixed on a horizontal table made of aluminum by a friction coefficient test method based on JIS P 8147, and a paper sample is placed on the SUS table in an overlapping manner.

  Next, a 1 kg stainless steel weight is placed directly on the paper sample, moved at a head speed of 500 mm / min, the friction resistance value between the paper and the stainless steel weight is measured with a load cell, and the surface friction coefficient = metal friction resistance. Calculated as value × 0.01. The surface roughness of the friction surface with the paper sample of the stainless steel weight was 0.5 μm as measured with a stylus type surface roughness measuring instrument in accordance with JIS P 0651. As the tensile tester, Strograph M1 manufactured by Toyo Seiki Co., Ltd. or a tensile tester having equivalent performance is used.

  The pseudo adhesive paper according to the present invention (Examples 1 to 12 below) and the pseudo adhesive paper different from the present invention (Comparative Examples 1 to 10 below) were tested and evaluated for transportability in an electrophotographic recording apparatus.

The base paper is a pulp slurry prepared by beating a raw pulp composed of 50% bleached paper pulp 50%, LBKP 40% and bleached PGW 10% with a refiner to a Canadian freeness of 350 cc. AKD) was added, and this prepared raw material pulp was made with a long paper machine. No.1 to No.6 base papers of different types are prepared by adjusting the papermaking raw material discharge rate for the opening papermaking speed of the headbox raw material discharge port (lip) at the time of papermaking, and by shaking the wire in the wire part (rolling). Got. Each base paper was coated on both sides with a general size press solution containing an inorganic pigment and starch on both sides at 1.5 g / m ² . The basis weights were all adjusted to 130.0 g / m ² .
The base paper No. No. 1 was a surface fiber orientation ratio of 1.75, a back fiber orientation ratio of 1.60, and a front and back fiber orientation ratio difference of 0.15.
Base paper No. 2 had a surface fiber orientation ratio of 1.80, a back fiber orientation ratio of 1.65, and a front and back fiber orientation ratio difference of 0.15.
Base paper No. 3 had a surface fiber orientation ratio of 1.90, a back fiber orientation ratio of 1.65, and a front and back fiber orientation ratio difference of 0.30.
Base paper No. No. 4 had a surface fiber orientation ratio of 2.00, a back fiber orientation ratio of 1.60, and a front and back fiber orientation ratio difference of 0.40.
Base paper No. No. 5 had a surface fiber orientation ratio of 2.10, a back fiber orientation ratio of 1.60, and a front and back fiber orientation ratio difference of 0.50.
Base paper No. 6 had a surface fiber orientation ratio of 2.00, a back fiber orientation ratio of 1.60, and a front and back fiber orientation ratio difference of 0.50.

  On the other hand, the pseudo-adhesive layer was prepared by adding 10 parts by weight of a synthetic rubber latex / water-soluble binder to a dispersion containing 30 parts by weight of natural rubber latex, 25 parts by weight of silica (Grace Devison: W500) and 25 parts by weight of raw starch. The pseudo-adhesive produced by addition was applied and formed by a free-fall curtain coater. The amount of the pseudo adhesive applied in each example and comparative example is shown in Table 1 below.

  On the other hand, about the present Example and the comparative example, the flattening process was performed in the flattening processing equipment after coating, and the friction coefficient was adjusted. Since the flattening treatment of this type of pseudo adhesive layer is preferably performed in a combination of a metal roll and a metal roll or a combination of a metal roll and an elastic roll in at least two nips, the metal roll is also used in this embodiment. A friction coefficient was prepared by performing a flattening process by a two-nip process using a combination of an elastic roll and an elastic roll.

  On the other hand, the surface electrical resistance values of the present examples and comparative examples were adjusted by adding sodium sulfate as a conductive agent to the pseudo adhesive. The surface electrical resistance values of the examples and comparative examples are shown in Table 1 below.

  The fiber orientation angle was measured with an optical orientation tester (FOT) manufactured by Toyo Seiki Seisakusho. Specifically, laser light having a wavelength of 685 nm was irradiated at a constant angle with respect to the paper surface, and the fiber orientation angle was measured from the change in the intensity of reflected light.

  The residual curl value was determined by supporting a paper sample cut to 100 mm square at one point on the center of the diagonal line, and in this supported state, the ambient humidity was 50% RH → 65% RH → 80% RH → 65% in an environment of 20 ° C. RH → 50% RH → 35% RH → 20% RH → 35% RH → 50% RH In this order, the paper sample is changed continuously every 4 hours, and the paper sample becomes equilibrium moisture at the final 50% RH. Place the sample on a horizontal table so that the curl convex part is on the bottom, measure the distance of the perpendicular from each vertex of the paper sample to the horizontal table, and calculate the average value of the measured distances. Is the value obtained.

  The surface dynamic friction coefficient was measured based on JIS P 8147, and the surface friction coefficient was measured based on JIS P 0651.

  [Stain] in the evaluation column in the table indicates that when 1000 samples of A3 size were copied on the entire print area using a Canon electrophotographic copying machine model number NP6550 It is evaluated by visually observing and evaluating the presence or absence of stains in the device. ○ indicates that there is no stain, × indicates that the stain is generated, and indicates that there is some stain but that does not interfere with printing. It was evaluated as Δ.

  [Paper jam] is also the same as that for each sample of 1000 A3 size images, using a Canon electrophotographic copier model NP6550 to copy 13-point characters over the entire printing area. Were observed and evaluated. In the evaluation of the paper jam, the case where no paper jam occurred was evaluated as “◯”, and the case where the paper jam occurred was evaluated as “X”.

  [Multi-feeding] is also the same as that of 1000 A3 specimens. Using a Canon-made electrophotographic copying machine, Model No. NP6550, 13-point characters are copied over the entire printing area. Observed and evaluated. In the evaluation of double feedability, the case where double feed did not occur was evaluated as ○, and the case where it occurred was evaluated as ×.

  Here, looking at Table 1, as shown in the evaluation column, the pseudo-adhesive paper (Example) according to the present invention causes paper jams, stains, and double feed when used in an electrophotographic recording apparatus. It is found that they are not. On the other hand, in the comparative example, any of paper jam, dirt, and double feed occurs when used in the electrophotographic recording apparatus. As a result, it can be said that the pseudo-adhesive paper of the present invention has excellent transportability in the electrophotographic recording apparatus.

  It can be used for pseudo-adhesive paper that is printed and printed by an electrophotographic recording apparatus, for example, a front paste type confidential information hiding sheet, a confidential postcard, and a confidential envelope.

Claims (3)

On both sides of the base paper, there is a pseudo-adhesive layer that can be pseudo-bonded in a peelable manner when given conditions are not adhered under normal conditions, and characters and figures are printed and printed on the surface of the pseudo-adhesive layer. A so-called pre-glue type pseudo-adhesive paper,
Pretreated according to JIS P 8111, measured surface electrical resistance value is 6 × 10 ⁹ to 1 × 10 ¹² , surface friction coefficient is 0.1 to 0.4, and the following residual curl value is 20 mm or less. A pseudo-adhesive paper characterized by that.
(Residual curl value)
The residual curl value is calculated according to the following (A) to (F).
(A) The size of the paper sample is 100 mm square.
(B) The center of the diagonal line of the sample is supported at one point.
(C) Ambient humidity in a supported state at 20 ° C. is 50% RH → 65% RH → 80% RH → 65% RH → 50% RH → 35% RH → 20% RH → 35% RH → Change continuously every 4 hours in the order of 50% RH.
(D) After the paper sample has reached equilibrium moisture at the final 50% RH, the paper sample is placed on a horizontal table with the curl convex portion facing downward.
(E) The perpendicular distance from each vertex of the four corners of the paper sample to the horizontal base is measured.
(F) Let the average value of the measured distance be a residual curl value.   The pseudo-adhesive paper according to claim 1, wherein the absolute value of the difference in fiber compounding ratio between the front and back surfaces is 0.4 or less. The pseudo-adhesive paper according to claim 1 or 2, wherein a difference in coating amount of the pseudo-adhesive on the front and back surfaces is 5 g / m ² or less.