JPH093433A - Adhesive composition for classifying pressure-sensitive copying paper - Google Patents

Abstract

PURPOSE: To obtain the subject composition containing colloidal silica having a specific particle diameter, exhibiting a strong adhesive force between respective paper sheets composing a set, enabling the extremely easy mutual separation of sets, and not expressing stickiness, even when coated on the cut surfaces of the paper sheets. CONSTITUTION: The adhesive composition comprises (A) a water-soluble polymer (e.g. starch, sodium aliginate) and/or a polymer emulsion (e.g. styrene-butadiene copolymer emulsion, vinyl acetate polymer emulsion), (B) a surfactant (e.g. an anionic surfactant such as sodium laurylsulfate), and (C) colloidal silica having an average particle diameter of <=10nm. The component A is preferably mixed in an amount of 5-20wt.% based on the objective composition, and the component C is also preferably mixed in an amount of 20-150wt.% based on the component A. The composition may further be compounded with a plasticizer such as sorbitol, and a sensitivity-reducing agent such as an alkylamine- polyethylene glycol adduct in addition to the components A to C and water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition for assembling pressure-sensitive copying paper forming a set.

[0002]

2. Description of the Related Art A pressure-sensitive copying paper is prepared by dissolving an electron-donating organic color former or the like in oil and coating a color-forming agent microcapsule composition mainly composed of microcapsules encapsulating oil droplets on one side of a support. The above-mentioned upper paper, and one side of the support were coated with a color-developing layer containing an electron-accepting color-developing agent that is colored when contacted with the above-mentioned color-developing agent, and the opposite side was coated with the color-developing agent microcapsule composition. It is composed of a middle sheet and a lower sheet having a color layer coated on one side of the support. Vouchers using these pressure-sensitive copy papers have been put to practical use as a copy set of upper paper / lower paper or a large number of copy sets in which a middle paper is sandwiched between upper paper / lower paper. In the assembly of a plurality of copy sets, the pressure-sensitive copy paper forming such a set is grouped by applying an adhesive to one end of the stacked sheets and then separating them into each set after drying. Be seen.

In this case, strong adhesion is required between the papers forming each set, and it is necessary to easily separate the sets. In addition, in recent years, there have been many opportunities to print slips on printers. In this case, if the cutting surface coated with adhesive has adhesiveness, running troubles such as slips not separating from the feed roll occur, so adhesive It was necessary to suppress the tackiness of the cut surface coated with.

Conventionally, water-soluble polymers, polymer emulsions and the like have been used as adhesives for grouping.
When these were used alone, sufficient adhesive strength could not be obtained between the papers making up each set, and separation between each set was also insufficient. Therefore, it has been proposed to use a water-soluble polymer in combination with a surfactant (Japanese Patent Publication No. 53-12844) and a polymer emulsion in combination with a surfactant (Japanese Patent Publication No. 53-12845). Although the adhesive strength and the separation between the sets have been considerably improved, there is a problem that the cutting surface coated with the adhesive has tackiness and often causes troubles during printing on the printer. This tendency was particularly remarkable under high humidity conditions.

On the other hand, Japanese Patent Laid-Open No. 4-323287 proposes a method in which a water-soluble phosphate is added to a polymer emulsion, but it is not possible to completely prevent the cut surface from sticking. There wasn't.

[0006]

DISCLOSURE OF THE INVENTION The present invention has a strong adhesive force between sheets constituting a set, can be separated from each set very easily, and has a cutting surface coated with an adhesive. The purpose is to obtain an adhesive for assembling pressure-sensitive copying paper having no tackiness.

[0007]

As a result of intensive studies, the present inventors have found that an adhesive composition for assembling pressure-sensitive copying paper composed of a water-soluble polymer or polymer emulsion and a surfactant. It was found that the above problems can be solved by adding colloidal silica having an average particle diameter of 10 nm or less, and the present invention has been completed.

That is, the present invention provides an adhesive composition for assembling pressure-sensitive copying paper comprising a water-soluble polymer and / or polymer emulsion and a surfactant, wherein the adhesive composition is further averaged. The present invention relates to an adhesive composition for assembling pressure-sensitive copying paper containing colloidal silica having a particle size of 10 nm or less.

The adhesive composition of the present invention contains colloidal silica having an average particle size of 10 nm or less in addition to the water-soluble polymer and / or polymer emulsion and the surfactant. Colloidal silica is a colloidal solution in which water is used as a dispersion medium and ultrafine particles of silicic acid anhydride are dispersed in water.
Generally, what is handled as a colloidal solution has a particle size of the dispersoid of 1 nm to 100 nm. The colloidal silica having an average particle size of 10 nm or less used in the present invention is also in this range, but if the average particle size is larger than 10 nm, it is effective in preventing sticking but the adhesion is hindered by the colloidal silica. Sufficient binding strength cannot be obtained between the constituent papers. Therefore, only by using the colloidal silica having an average particle diameter of 10 nm or less, it is possible to obtain both prevention of sticking on the cut surface and sufficient binding strength. In the present invention, the content of colloidal silica is 10 to 400% by weight, more preferably 20% by weight, based on the water-soluble polymer or polymer emulsion.
Is about 150% by weight.

Examples of the water-soluble polymer used in the present invention include starch, sodium alginate, acacia, dextrin, glue, gelatin, casein, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and other natural polymers, polyvinyl alcohol, Examples thereof include water-soluble synthetic polymers such as polyacrylamide, polyethyleneimine, polyacrylic acid, maleic acid copolymer, and acrylic copolymer.

The polymer emulsion used in the present invention means a liquid in which a water-insoluble or sparingly soluble polymer substance is emulsified in water. For example, styrene-butadiene copolymer emulsion, acrylic acid ester copolymer emulsion, styrene-acrylic acid ester copolymer emulsion, butadiene-acrylic acid ester copolymer emulsion, vinyl acetate polymer emulsion, vinyl acetate-acrylic acid ester Examples thereof include copolymer emulsions, but not limited thereto.

The water-soluble polymer and the polymer emulsion used in the present invention may be used alone or in admixture of two or more. The content of these is not particularly limited, but 5 to 20% by weight of the adhesive composition is a desirable range.

The surfactant used in the present invention includes:
Anionic and nonionic surfactants can be used. Examples of the anionic surfactant include sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, and sodium salt of a naphthalenesulfonate formalin condensate. Further, as a nonionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oxypropylene block polymer, polyethylene glycol fatty acid ester,
Examples thereof include sorbitan fatty acid ester and polyoxyethylene sorbitan fatty acid ester.

In the adhesive composition of the present invention, the composition other than the above-mentioned water-soluble polymer, polymer emulsion, surfactant and colloidal silica is water, but polyethylene glycol is used within the range that does not impair the effects of the present invention. , A sorbitol or other plasticizer, and a desensitizer such as an alkylamine polyethylene glycol adduct. Moreover, you may add methyl alcohol and ethyl alcohol as needed.

The adhesive composition for assembling the pressure-sensitive copying paper of the present invention can be applied to various pressure-sensitive copying papers known in the art, and it can be used as a coloring agent or a coloring agent for pressure-sensitive copying paper. The types of microcapsules, binders, etc. are not particularly limited and can be used within the range usually used by those skilled in the art.

[0016]

The adhesive composition of the present invention strongly adheres to each paper constituting a set and separates very easily between each set, and therefore is excellent as an adhesive for assembling pressure-sensitive copying paper. ing. The adhesive composition of the present invention shows a strong adhesive force by penetrating well into the coating layer coated with the color-forming agent microcapsules or the coating layer coated with the color-developing agent in the pressure-sensitive copying paper, but it is not coated. It has no permeability and does not adhere to the surface. Therefore, when used in an assembly of a plurality of copy sets, for example, the surface opposite to the surface having the color former microcapsule layer of the upper paper and the surface having the color former layer of the lower paper, which come into contact when the sets are stacked, are used. It is considered that the opposite surfaces will not be glued and can be grouped into sets.

Further, the cut surface coated with the adhesive does not exhibit tackiness. The reason for this is not clear, but it is speculated that the viscous film (film) is formed by containing the colloidal silica, which is an inorganic substance, and this does not have tackiness, so the tackiness of the adhesive is suppressed. To be done.

[0018]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Example 1 Polyvinyl alcohol (Kuraray Co., PV
7% by weight of A103) as solid content, 0.3% by weight of sodium lauryl sulfate, and 3% by weight of colloidal silica having an average particle diameter of 5 nm (Snowtex ST-XS, manufactured by Nissan Kagaku Co.) as solid content and ethyl alcohol. Add 5% by weight,
The necessary water was added thereto and mixed uniformly to obtain an adhesive composition.

[Example 2] Polyvinyl alcohol (PVA103 manufactured by Kuraray Co., Ltd.) as solid content 6% by weight, sodium lauryl sulfate 0.3% by weight, colloidal silica having an average particle diameter of 5 nm (Nissan Chemical Co., Ltd., Snowtex) ST-
XS) as a solid content of 6% by weight and ethyl alcohol of 3% by weight.
% By weight, necessary water was added thereto, and the mixture was uniformly mixed to obtain an adhesive composition.

Example 3 Styrene-Butadiene Copolymer Emulsion (Sumitomo Nogatac SN316)
As solids, 8% by weight as solids, 0.01% by weight as sodium lauryl sulfate, and 2% by weight as solids colloidal silica having an average particle size of 5 nm (Snowtex ST-XS, manufactured by Nissan Chemical Co., Ltd.), and necessary water Was added and mixed uniformly to obtain an adhesive composition.

[Example 4] Styrene-butadiene copolymer emulsion (SN316 manufactured by Sumitomo Nogatak Co., Ltd.)
As solids, 8% by weight as solids, 0.01% by weight as sodium lauryl sulfate, and 5% by weight as solids, colloidal silica having an average particle size of 5 nm (Snowtex ST-XS, manufactured by Nissan Chemical Co., Ltd.), and water necessary for it Was added and mixed uniformly to obtain an adhesive composition.

[Example 5] 7% by weight of styrene-acrylic copolymer emulsion (KG2010 manufactured by Arakawa Chemical Co., Ltd.) as solid content, 0.1% by weight of sodium lauryl sulfate, and colloidal silica having an average particle size of 5 nm (Nissan Chemical Co., Ltd.) Manufactured by
Snowtex ST-XS) was added as a solid content in an amount of 7% by weight, and necessary water was added thereto and uniformly mixed to obtain an adhesive composition.

[Example 6] Polyvinyl alcohol (PVA103 manufactured by Kuraray Co., Ltd.) as a solid content of 7% by weight, sodium lauryl sulfate 0.3% by weight, and colloidal silica having an average particle diameter of 8 nm (Nissan Chemical Co., Ltd., Snowtex) 3% by weight of S) as solid content and 5% by weight of ethyl alcohol were added, and necessary water was added thereto and uniformly mixed to obtain an adhesive composition.

[Example 7] Polyvinyl alcohol (Kuraray Co., Ltd., PVA103) as a solid content of 7% by weight, polyoxyethylene lauryl ether 2% by weight, and colloidal silica having an average particle size of 5 nm (Nissan Chemical Co., Ltd., Snowtex) (ST-XS) was added as a solid content in an amount of 3% by weight and ethyl alcohol in an amount of 5% by weight, and necessary water was added thereto and uniformly mixed to obtain an adhesive composition.

[Example 8] Polyvinyl alcohol (Kuraray Co., Ltd., PVA103) as solid content 5% by weight, styrene-butadiene copolymer emulsion (Sumitomo Nogatak Co., SN316) as solid content 4% by weight, lauryl Colloidal silica with 0.3% by weight of sodium sulfate and an average particle size of 5 nm (manufactured by Nissan Chemical Co., Ltd., Snowtex ST-
XS) as solid content 3% by weight, ethyl alcohol 5%
% By weight, necessary water was added thereto, and the mixture was uniformly mixed to obtain an adhesive composition.

Example 9 Polyvinyl alcohol (PVA103 manufactured by Kuraray Co., Ltd.) as solid content 3% by weight, sodium lauryl sulfate 0.2% by weight, colloidal silica having an average particle size of 5 nm (Nissan Chemical Co., Ltd., Snowtex) ST-
10% by weight of XS) as a solid content and 5% by weight of ethyl alcohol were added, and necessary water was added thereto and uniformly mixed to obtain an adhesive composition.

Comparative Example 1 The same treatment as in Example 1 was carried out except that the colloidal silica having an average particle diameter of 5 nm (Snowtex ST-XS manufactured by Nissan Chemical Industries, Ltd.) was not used.

[Comparative Example 2] The same treatment as in Example 3 was carried out except that colloidal silica having an average particle diameter of 5 nm (Snowtex ST-XS, manufactured by Nissan Chemical Industries, Ltd.) was not used.

Comparative Example 3 In Example 1, colloidal silica having an average particle diameter of 5 nm (Snowtex ST-XS manufactured by Nissan Chemical Co., Ltd.) was used. Colloidal silica having an average particle diameter of 15 nm (Snowtex ST- manufactured by Nissan Chemical Co., Ltd.) was used. The same treatment as in Example 1 was carried out except that 20) was substituted.

[Comparative Example 4] The same treatment as in Example 1 was carried out except that polyvinyl alcohol (PVA103 manufactured by Kuraray Co., Ltd.) was not used.

Table 1 shows the evaluation results of the examples and comparative examples. The evaluation method is as follows. Commercially available pressure-sensitive copying paper (Jujou CCP Ace) from top to top, middle paper,
One set of the medium paper and the lower paper is set in this order, and after cutting 500 sets, the adhesive compositions obtained in Examples and Comparative Examples are applied to the cut surface with a brush for painting at the same location four times. It was applied so that it would pass. Regarding the adhesive strength and the set separability, the adhesive was applied under the environment of a humidity of 60% and a temperature of 20 ° C., and it was confirmed after 1 hour. Regarding the tackiness, the adhesive was applied under the environment of humidity of 90% and temperature of 35 ° C., and it was confirmed after 1 hour.

(Adhesive strength) The adhesive strength between each piece of paper was measured using a universal tensile tester with a paper width of 5 cm, and the result was expressed as the weight per 1 cm of the width of the adhered paper piece. (Set Separability) 500 sets of pressure-sensitive copying paper were manually separated, and the state of adhesion between the lower paper and the upper paper at that time was observed. ◎ There is no adhesion between the paper and the top paper ○ It adheres, but it easily peels off △ It adheres and does not easily peel off × It adheres and does not peel at all (tacky) On the cutting surface coated with the adhesive composition, Sensory evaluation was performed by touching the hands. ○ No stickiness △ Somewhat sticky feel × Very sticky feel

[0033]

[Table 1]

In Table 1, "upper-middle" means between the upper sheet and the middle sheet. Similarly, the middle-intermediate indicates the distance between the middle paper and the middle paper, and the middle-lower indicates the distance between the middle paper and the lower paper. The adhesives of Examples 1 to 9 satisfying the requirements of the present invention have high adhesive strength between the papers constituting the set, excellent set separability, and excellent adhesiveness on the coated surface. . On the other hand, in the case of Comparative Examples 1 and 2 which did not contain colloidal silica, the adhesive strength was low and the tackiness of the coated surface was remarkable. Also, the average particle size of colloidal silica is 10
Comparative Example 3 in which the average particle size exceeds nm and Comparative Example 4 containing no water-soluble polymer also had poor adhesive strength.

[0035]

As described above, the adhesive composition of the present invention penetrates well between the sheets constituting the set and strongly adheres, but does not penetrate between the sets and has good separability. Therefore, it is possible to easily and smoothly classify the sets of pressure-sensitive copying paper forming the sets. Further, the adhesive composition of the present invention does not exhibit tackiness even when applied to a cutting surface, and when printing a slip with a printer, printing can be smoothly performed without running trouble even under high humidity conditions, It is an excellent adhesive composition with high practicality.

Claims (1)

[Claims] 1. An adhesive composition for assembling pressure-sensitive copying paper comprising a water-soluble polymer and / or polymer emulsion and a surfactant, wherein the adhesive composition further has an average particle size of 10 nm. An adhesive composition for assembling pressure-sensitive copying paper, characterized by containing the following colloidal silica.