JP2005213468A - Self adhesive emulsion coating for compression-bonding paper after applying paste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self adhesive emulsion coating for a compression-bonding paper, without forming a solidly fixed component on a roll surface even after passing through coatings many times, and capable of producing a high quality paper for compression-bonding without forming tensed parts and creases. <P>SOLUTION: This self adhesive emulsion coating used for a compression-bonding method of performing a business form-printing or the business form-printing and a laser printer-printing on a stock paper, then applying the pressure sensitive adhesive, drying, folding and then compression-bonding is provided by including a natural rubber-based adhesive component, an organic filler and/or inorganic filler, wherein the organic filler and/or inorganic filler are particles having smooth surface properties without having sharp points. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a self-adhesive emulsion paint having an adhesive function that can be adhered by applying a high pressure even after drying, and cannot be re-adhered by ordinary means after peeling.

  In recent years, a mail system for sending a postcard has been applied so that the secret of the contents can be kept instead of a sealed letter. Conventionally, as such a mail system, a confidential label that attaches a label to a predetermined part of a postcard and conceals the content of the description is best known, but recently, in the field of various postcards for direct notification, direct mail, A pressure-sensitive adhesive layer is formed on the base paper, folded in half or in three (N-fold), and the contact surfaces (pressure-sensitive adhesive layer) are temporarily bonded together with pressure, and the adhesive surface is subjected to an intentional operation. Crimp postcards that can be easily peeled off are rapidly spreading. An example (N-folding) of such a crimped postcard is shown in FIG. In such a postcard, other surfaces can be concealed and concealed on the surface with the description to be kept secret, and after the adhesive surface is peeled off, it cannot be re-adhered without using a predetermined device. Cheating can also be prevented.

  Conventionally, as a pressure-sensitive adhesive paper as described above, after applying business form printing and laser printer printing on a base paper, a so-called post-glue is applied in the form of a postcard by applying a UV curable pressure varnish as a pressure sensitive adhesive and applying pressure. Crimp paper has been used (see, for example, Patent Documents 1 to 3). FIG. 2 shows a conceptual diagram of such a post glue press sheet. As shown in FIG. 2, in the post-glue pressure-bonding paper, first, a business form print 3 that forms a fixed sentence or chart of a document is applied on the base paper 1, and UV irradiation for fixing the business form printing ink 3 is performed. And print document contents such as personal information with a laser printer or the like. Subsequently, a UV curable crimping varnish is applied, the UV curable crimping varnish is half-cured by UV irradiation, the paper is cut into desired dimensions, and then folded and pressed to perform temporary adhesion. Finally, the film is thermally cured under predetermined conditions to perform main bonding.

  However, on post-glue pressure-bonded paper, UV curing pressure bonding varnish does not have the ability to wear toner for laser printers, so it is not possible to perform off-line printing from above UV curing pressure bonding varnish. There was a problem. Further, since the surface properties until pasting after pasting is semi-dry, there is a problem with blocking resistance, and it is impossible to take up or finish a continuous form.

  In order to improve the printability and blocking resistance, a method of adding a filler composed of an organic filler and / or an inorganic filler is known. In this method, it is required by adding a filler. There was a disadvantage that adhesive strength could not be obtained.

  Therefore, in recent years, as a pressure-sensitive adhesive as described above, development of a self-adhesive emulsion paint having a self-adhesive property that does not lose adhesiveness after the paint is dried has been promoted. This self-adhesive emulsion paint generally has a constitution in which an adhesive component such as natural rubber is emulsified and suspended as emulsion particles in a dispersion medium, and various resins, fillers and the like are added as other non-adhesive components. This self-adhesive emulsion paint is first applied to a roll part of a coating machine, an excess paint is scraped off by a measuring blade, a certain amount is measured, and then transferred to a base paper. The pressure-bonded paper to which the paint has been transferred evaporates the dispersion medium through a drying process, cuts the paper into a desired size, folds and presses it, and temporarily attaches it to form a postcard or the like.

JP-A-11-349854 (Examples, abstract) JP 2000-136320 A (Example, abstract) JP2003-238905 (Examples, abstract)

  However, in the case of conventional self-adhesive emulsion paints, when the application to the base paper is carried out many times (several hundreds or more), the shearing force applied to the paint, such as the measuring blade in the coating measuring section, the paint transfer section to the base paper, etc. In the part where the paint is applied, part of the paint component gradually adheres to the roll, forming a film that accumulates and dries (hereinafter referred to as skin burr), and this skin burr is mixed into the self-adhesive emulsion paint. In other words, it has a problem of being transferred together on the base paper. Further, the unevenness formed on the surface of the roll due to fixation of the solid content causes a problem that unevenness (hereinafter referred to as streak) is also formed on the surface of the paint layer (pressure-sensitive adhesive layer) transferred onto the base paper. Had.

  When these burrs and streaks are formed, the adhesive strength becomes unstable at the stage of folding and pressurizing the crimping paper in the subsequent process, and the transparency of the paint layer becomes unstable, making it difficult to read the document contents. It was a serious defect as a crimped paper. For this reason, it has been necessary to take measures such as periodically stopping the production line and cleaning the transfer roll.

  As a result of intensive studies on the causes and prevention methods of skin burrs and streaks, the present inventors have found that the surface of amorphous particles contained as organic fillers and inorganic fillers in self-adhesive emulsion paints is sharp. The corners break the protective film composed of surfactants and emulsifiers on the surface of the emulsion particles dispersed in the dispersion medium, and the broken emulsion particle components and the other components in the dispersion medium or dispersion medium are mixed. It was found that the properties of the paint as an emulsion are lost, the drying property is enhanced, and a fixing component is generated on the roll surface.

  The present invention has been made in view of the above circumstances, and even when the coating from the roll to the base paper has been performed many times, no fixing component is generated on the surface of the roll, and there is no occurrence of skin burrs or streaks. An object of the present invention is to provide a self-adhesive emulsion paint for a pressure-bonding paper capable of producing a high-quality pressure-bonding paper.

  The self-adhesive emulsion paint for post-glue pressure-bonding paper of the present invention is obtained by applying a business form printing or a business form printing and a laser printer printing on a base paper, applying and drying a pressure sensitive adhesive, folding and pressurizing the adhesive. A self-adhesive emulsion paint for a post-glue pressure-bonding paper used in a post-glue pressure-bonding method, comprising a natural rubber adhesive component, an organic filler and / or an inorganic filler. The organic filler and / or the inorganic filler are characterized by being particles having smooth surface properties without corners.

  Such a self-adhesive emulsion paint of the present invention has a smooth surface property because the particle surface of the organic filler and / or inorganic filler contained in the paint does not have sharp corners. Therefore, the filler does not break the emulsion particles when a shearing force is applied to the paint during metering and coating. Therefore, the properties of the paint as an emulsion are maintained, and no burrs or streaks are generated.

Hereinafter, the self-adhesive emulsion paint of the present invention will be described in detail.
As the self-adhesive emulsion paint, any adhesive may be used as long as it is self-adhesive so that the adhesiveness is not lost even after drying and can be adhered by pressurization. A configuration in which non-adhesive components such as an adhesive component and a filler are added is preferable.

  Examples of such natural rubber-based components include raw natural rubber latex, vulcanized natural rubber latex, and natural rubber latex obtained by graft copolymerization with methyl methacrylate (MMA). Examples of the vulcanizing agent for the vulcanized natural rubber latex include sulfur, a sulfur-containing compound, an organic peroxide, a metal oxide, an organic polyvalent amine, and a modified phenolic resin.

  The filler of the present invention is a particulate filler, and can be classified into an organic filler and an inorganic filler.

  Examples of the organic filler include cellulose powder, sweet potato starch, potato starch, wheat starch, corn starch, rice starch, tapioca starch, styrene beads, and methyl methacrylate beads. Since these organic fillers have a large average particle size of 5 to 30 μm, when added to a pressure-sensitive adhesive, the surface of the pressure-sensitive adhesive layer can be uneven, and the adhesive force can be adjusted. Can improve blocking resistance and can impart slipperiness. Therefore, these organic fillers are preferably added in powder form. Further, for the purpose of the present invention, it is essential that these particles have a spherical or spindle-like smooth surface property, but are not particularly limited to a spherical or spindle-like shape, and may have a smooth surface property. . The effect of the present invention cannot be obtained with particles having a non-smooth surface such as amorphous particles.

  As a compounding ratio of the organic filler in this invention, 20-40 weight part is preferable with respect to 100 weight part of natural rubber-type components. If it is less than 20 parts by weight, it will cause blocking, and if it exceeds 40 parts by weight, the adhesive performance of the natural rubber component will be reduced.

  The inorganic filler is not limited as long as the surface property is smooth as in the case of the organic filler, and various fine particles can be used. In particular, spindle-shaped light calcium carbonate, spherical silica, and glass beads are spherical or spindle-shaped. Therefore, it is preferable. Heavy calcium carbonate, synthetic silica, talc, kaolin clay, zinc oxide, alumina, mica and the like are undesirable because they are amorphous. Among these inorganic fillers, it is desirable to use spherical silica when considering blocking resistance and acceptability of printing ink.

  As a compounding ratio of the inorganic filler in this invention, 10-50 weight part is preferable with respect to 100 weight part of natural rubber-type components. If the amount is less than 10 parts by weight, the inking property between the pressure-sensitive adhesive layer surface and the laser printer toner is reduced, and toner transfer occurs when the printing surfaces are bonded together and pressed. Moreover, when it exceeds 50 weight part, the adhesive performance of a natural rubber-type component will be reduced like the case of an organic filler.

  Moreover, additives such as a dispersant, an antifoaming agent, a surfactant, an anti-aging agent, an ultraviolet absorber, an antifungal agent, and a deodorant are added to the self-adhesive emulsion paint of the present invention as necessary. be able to.

  The base paper used for the pressure-bonded postcard paper of the present invention may be any paper formed from wood pulp as a main raw material, and LBKP alone or a mixture of NBKP and LBKP may be used. When NBKP and LBKP are mixed and used, a ratio in which the blending ratio of NBKP is 50% or less is preferable in consideration of paper quality. Furthermore, waste paper can be blended as long as the strength of the base paper can be maintained.

  Further, a paper strength enhancer can be internally added for the purpose of improving the strength of the wood pulp paper used as the base paper. As paper strength enhancers, polyacrylamide resins, polyamide epichlorohydrin resins, modified starches such as cationized starch and acetylated starch, melamine resins, urea resins, CMC, guar gum, modified guar gum, polyamide resins, polyamine resins, epoxy modified Examples thereof include polyamide.

  The beating degree of the base paper has a close relationship with the strength, and the strength increases as the beating degree increases. However, as the beating degree increases, the dimensional stability deteriorates rapidly. Therefore, it is necessary to compensate for the insufficient strength by adjusting the beating degree while maintaining the beating degree at 40 to 60 ° SR.

  The higher the surface strength of the paper, the better. Specifically, the surface strength (J TAPI No. 1 paper and paperboard—surface strength test method using wax) is preferably 14A or more. As coating chemicals, for example, oxidized starch, modified starch, polyvinyl alcohol (PVA), modified PVA, polyacrylamide resin, CMC, styrene resin, styrene maleic resin, styrene acrylic resin, etc. are applied to the paper surface. As a result, the surface paper strength can be 14 A or more. These are used alone or in combination.

  When a water-based color is used as a dispersion medium for a self-adhesive emulsion paint, it is desirable that the text size (JIS P8122) is 5 seconds or more because the paint penetrates if there is no size effect on the base paper. When the text size is less than 5 seconds, the self-adhesive emulsion paint does not exhibit the predetermined adhesion performance due to the penetration of the paint, and the size effect tends to vary, which is undesirable because the adhesive force varies. . In order to adjust the text sizing degree to 5 seconds or more, a sizing agent may be internally added or coated.

  Examples of the internal sizing agent include rosin, alkyl ketene dimer, alkenyl succinic anhydride, alkenyl succinic acid, and higher fatty acid. Surface sizing agents include styrene resin, styrene maleic acid resin, and styrene acrylic resin. Olefin resin, acrylic resin, diisobutylene-maleic anhydride and the like.

  Furthermore, an undercoat layer such as a clay coat layer can be provided between the base paper and the pressure-sensitive adhesive layer. By providing this clay coat layer, the smoothness of the surface is increased and the printability is improved.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

[Example]
A foam paper (trade name: KPF-N, manufactured by Kishu Paper Co., Ltd.) 81.4 g / m ² was coated with a pressure-sensitive adhesive having the following composition so that the coating amount was 3 g / m ² in solid content. The crimping postcard paper of the example was used.
MMA graft natural rubber adhesive 100 parts by weight Corn starch (manufactured by Nippon Shokuhin Kako) 20 parts by weight

[Comparative Example 1]
A pressure-sensitive adhesive having the following composition was used, and a pressure-bonded postcard paper of Comparative Example 1 was prepared in the same manner as in the Examples.
-MMA-grafted natural rubber adhesive 100 parts by weight-SBR (trade name: Nipol LX-416, manufactured by Nippon Zeon)-10 parts by weight-Synthetic silica (trade name: Cylicia 350, manufactured by Fuji Silysia Chemical) 30 parts by weight-Corn starch ( 20 parts by weight

[Comparative Example 2]
A pressure-sensitive adhesive having the following composition was used, and a pressure-sensitive postcard paper of Comparative Example 2 was prepared in the same manner as in the Examples.
MMA-grafted natural rubber adhesive 100 parts by weight SBR (trade name: Nipol LX-416, manufactured by Nippon Zeon) 10 parts by weight Heavy calcium carbonate (trade name: TR-200, manufactured by Okutama Kogyo) 20 parts by weight Corn starch (manufactured by Nippon Shokuhin Kako) 20 parts by weight

[Evaluation methods]
1. Skin burr Using a small UV / water-based coating machine (trade name: SAC-20, manufactured by Hirose Steel), 1000 pressure-sensitive postcard papers of Examples and Comparative Examples were respectively produced by the above-described composition and method. After the production, the paint on the head part of the coating machine was taken out, and the state of the skin burr of each transfer roll part was visually observed.

2. Streaks Out of the 1000 post-printed and post-crimped postcard papers, the 200th, 400th, 600th, 800th, and 1000th sheets were visually observed to generate streaks. The ones that were not done were marked with ◯, and the ones with streaks were marked with x.

[Evaluation results]
The evaluation results are shown in Table 1.

  As can be seen from Table 1, in the self-adhesive emulsion paint of the example, no burrs were observed even after 1000 sheets of coating, indicating good printability. In addition, streaks were observed on the 400th sheet in Comparative Example 1 and on the 800th sheet in Comparative Example 2, but streaks occurred even when the self-adhesive emulsion paint of the example exceeded 1000 sheets. Was not seen.

It is a schematic diagram which shows the crimping postcard paper of N character folding. It is a schematic diagram which shows the cross section of the conventional back adhesive pressure-bonding paper.

Explanation of symbols

1 Base Paper 2 UV Curing Crimp Varnish 3 Business Form Printing Ink 4 Laser Printer Toner

Claims (3)

Self-adhesive for post-glue pressure-bonding paper used for the post-glue pressure-bonding method, where business form printing or business form printing and laser printer printing are applied to the base paper, and then a pressure-sensitive adhesive is applied and dried, folded, pressed, and bonded. Emulsion paint,
The self-adhesive emulsion paint for post-glue pressure-bonding paper contains a natural rubber-based adhesive component, an organic filler and / or an inorganic filler,
A self-adhesive emulsion paint for post-glue pressure-bonding paper, wherein the organic filler and / or the inorganic filler are particles having smooth surface properties without corners.   The self-adhesive emulsion paint for post-glue pressure-bonding paper according to claim 1, wherein the organic filler and / or the inorganic filler are spherical particles.   The self-adhesive emulsion paint for post-paste pressure-bonding paper according to claim 1, wherein the organic filler and / or the inorganic filler are spindle-shaped particles.

Images