JPH066696B2 - Pressure sensitive adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is applied in advance to a predetermined portion of a printing form such as a paper or a form on which information is printed,
The present invention relates to a pressure-sensitive adhesive for binding a printing form by applying pressure, which is an adhesive condition after printing, and is used for sealing envelopes when creating envelopes, sticking when creating postcards, cards, etc. Adhesive for matching,
Alternatively, it is used as an adhesive for binding booklets and the like.

[Prior Art and its Problems] Conventionally, there have been pressure-sensitive adhesives for adhering various printing forms such as paper and forms, which mainly contain natural rubber, synthetic rubber, synthetic resin, etc. It was selected variously and used accordingly.

In recent years, many printers called non-impact printers have begun to be used, and a type of non-impact printer that employs an electrophotographic recording method fixes toner by thermocompression bonding. , For pressure sensitive adhesives composed mainly of synthetic resin,
The adhesive is softened in the printer, and the softened adhesive may be attached to the printer, which is an inconvenience.

In addition, the pressure-sensitive adhesive containing natural rubber as a main component is inconvenient because the adhesive has a low surface strength and the adhesive may adhere to the inside of the printer to damage the printer.

Furthermore, the above-mentioned conventional pressure-sensitive adhesives are not satisfactory in adhesiveness, heat resistance, blocking resistance, and storage stability when they are applied to a printing foam and used.

[Means for Solving Problems] As a result of intensive studies, the present inventor has achieved a desired object by adding silica gel in a specific ratio to NBR latex having a specific range of nitrile ratio. The inventors have found that a pressure-sensitive adhesive that can be obtained is obtained, and completed the present invention.

In the present invention, the nitrile ratio in NBR is 25-40%.
By adding 5 to 40 parts by weight, preferably 15 to 30 parts by weight of silica gel having an average particle size of 20 μ or less, preferably 1 to 10 μ, more preferably 2 to 6 μ to 100 parts by weight of NBR latex of In this way, a pressure-sensitive adhesive having dramatically improved properties, abrasion resistance, blocking resistance, and storage stability, and more excellent performance than conventional pressure-sensitive adhesives could be obtained.

The NBR latex and silica gel in the present invention are
As described in the examples, various nitrile ratios, those having different particle sizes are applicable, and the nitrile ratio is 25 to 40.
% NBR latex 100 parts by weight to which 15 to 30 parts by weight of silica gel having an average particle size of 1 to 10 μm is particularly excellent in adhesiveness and is suitable for use in mail envelopes, postcards and various cards. However, the pressure-sensitive adhesives described in the other examples can also be beneficially used based on the application of paper, forms, and binding.

Even if NBR latex is applied as a pressure-sensitive adhesive to a paper and dried, and then adhesives are brought into contact with each other and pressed, the adhesiveness is weak, and the nitrile ratio of the present invention is 25 to 40%.
Similarly, R-latex itself has weak adhesiveness, but the pressure-sensitive adhesive of the present invention can be used as a pressure-sensitive adhesive by adding 5 to 40 parts by weight of silica gel to 100 parts by weight of NBR latex. It is effective in various performances, and the reason is not clear, but NBR is applied to silica gel.
Are adsorbed to increase the surface area, silica gel acts as a kind of reinforcing agent to increase the strength of the adhesive, and as shown in FIG. 1, the pressure-sensitive adhesive applied to the printing foam 1 in a thickness of about 5 μm. This is probably because the coated surface of the agent 2 becomes uneven due to the silica gel 3.

The pressure-sensitive adhesive of the present invention is SBR latex to which silica gel is added.
A wetting agent, a thickening agent, an antifoaming agent and the like can also be added.

EXAMPLES Next, the present invention will be described in more detail with reference to examples. Since it is apparent that a wide variety of different embodiments can be constructed without violating the spirit and scope of the invention, the invention is restricted to these particular embodiments, except as limited in the following claims. It is not something that will be done.

Throughout the specification, all parts mean parts by weight. The performances of Examples and Comparative Examples were measured by the following method when a pressure-sensitive adhesive was applied on a paper to a thickness of about 5μ.

Adhesiveness: A sealing machine for printing foam pressure bonding was used. The pressing force is about 100 kg / cm ² .

Blocking resistance: After leaving for 1 hour in a constant temperature bath at each temperature of 30 ° to 70 ° C. under a load of about 500 g / cm ² , a peeling test was performed using a Tensilon universal tensile tester.

Abrasion resistance: The adhesive surface is abraded while applying a load of 200 to 500 kg / cm ² .
The strength of the adhesive surface was examined.

Heat resistance: A load of 1 to ³ kg / cm ² was applied, the adhesive surface was pressed against a hot roll at 200 ° C., and the state of the adhesive surface was examined.

Example 1 NBR latex “Nipol 5161” (trade name; manufactured by Zeon Corporation, nitrile ratio 40%, solid content 41%) 100 parts by weight of silica gel “SIPERNAT 22S” (trade name; manufactured by Nippon Aerosil Co., Ltd., particle size 5 μ) Was added to 12 parts by weight and sufficiently stirred to prepare a pressure sensitive adhesive A.

Similarly, 20 parts by weight of silica gel "SIPERNAT 22S" was added to 100 parts by weight of NBR latex "Nipol 5161" to prepare a pressure sensitive adhesive B.

Similarly, 26 parts by weight of silica gel "SIPERNAT 22S" was added to 100 parts by weight of NBR latex "Nipol 5161" to prepare a pressure-sensitive adhesive C.

Example 2 NBR latex "Nipol 5162" (trade name; manufactured by Zeon Corporation, nitrile ratio 32%, solid content 41%) 100 parts by weight of silica gel "Cyloid 244" (trade name; manufactured by Fuji Devison Co., particle size 3 μ) Was added and the mixture was sufficiently stirred to prepare a pressure-sensitive adhesive D.

Similarly, 20 parts by weight of silica gel "Cyloid 244" was added to 100 parts by weight of NBR latex "Nipol 5162" to prepare a pressure sensitive adhesive E.

Similarly, 35 parts by weight of silica gel "Cyloid 244" was added to 100 parts by weight of NBR latex "Nipol 5162" to prepare a pressure sensitive adhesive F.

Example 3 NBR latex "Crosslen NA-10" (trade name; Takeda Yakuhin Kagaku KK, nitrile ratio 35%, solid content 40%) 100 parts by weight of silica gel "N-300A" (trade name; Nippon Silica Industry Co., Ltd.) , Particle size 3 μ) was added and sufficiently stirred to prepare a pressure sensitive adhesive G.

Similarly, 27.4 parts by weight of silica gel "Nipseal N-300A" was added to 100 parts by weight of NBR latex "Crosslen NA-10" to prepare a pressure-sensitive adhesive H.

Example 4 NBR latex "LACSTER 750" (trade name; manufactured by Dainippon Ink and Chemicals, Inc., nitrile ratio, solid content: 42%) 100 parts by weight, silica gel "Cyloid 404" (trade name; manufactured by Fuji Devison, particle size) 15 parts by weight of 10 μ) and sufficiently stirred to prepare pressure-sensitive adhesive I.

Similarly, 26 parts by weight of silica gel "SIPERNA T22S" was added to 100 parts by weight of NBR latex "LACSTER 750" to prepare a pressure sensitive adhesive J.

Comparative Example 1 A pressure-sensitive adhesive K was prepared by adding 3 parts by weight of a tackifier "Hitanol 1501" (trade name; manufactured by Hitachi Chemical Co., Ltd.) to 100 parts by weight of natural rubber latex, and further adding 10 parts by weight of casein. did.

Comparative Example 2 15 parts by weight of silica gel "Cyloid 244" was added to 100 parts by weight of NBR latex "LACSTER 610" (trade name; manufactured by Dainippon Ink and Chemicals, Inc., nitrile ratio 21%, solid content 42%) to obtain a pressure-sensitive adhesive L. Prepared.

Comparative Example 3 NBR latex "CHIMIGUM LCG-3077" (trade name; manufactured by Goodyear, nitrile ratio 45%, solid content 35%) 100
20 parts by weight of silica gel "Cyloid 244" was added to parts by weight to prepare a pressure sensitive adhesive M.

Comparative Example 4 A pressure-sensitive adhesive N was prepared by adding 3.5 parts by weight of silica gel "N-300A" to 100 parts by weight of NBR latex "Crosslen NA-10".

Comparative Example 5 A pressure-sensitive adhesive O was prepared by adding 43.5 parts by weight of silica gel "N-300A" to 100 parts by weight of NBR latex "Crosslen NA-10".

The pressure-sensitive adhesives A to J of the present invention prepared in the above Examples 1 to 4
Table 1 shows the test results of the adhesiveness, blocking resistance, heat resistance, and abrasion resistance of the pressure-sensitive adhesives K to O prepared in Comparative Examples 1 to 5.

[Effects of the Invention] As is clear from the test results, the pressure-sensitive adhesive of the present invention has excellent performance in all items of adhesiveness, blocking resistance, heat resistance, and abrasion resistance. is there.

Therefore, the pressure-sensitive adhesive of the present invention is a kind of printing foam, and is shown in FIG.
It is particularly effective when the pressure-sensitive adhesive 2 of the present invention is applied to the adhesive portion of the double-sided envelope forming form 5 shown in FIG. 3 and applied to a thickness of about 3 to 6 μ. In addition to the print form shown in FIG. 3, a folded envelope form,
It is effective to be applied to print forms such as postcard forms, various notifications, binding, and window-opening folded envelope forms by rough coating.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing a state in which the pressure-sensitive adhesive of the present invention is applied on a printing foam, and FIG. 2 is a kind of printing foam of the pressure-sensitive adhesive of the present invention. FIG. 3 is an explanatory view showing a state in which it is applied to a certain tri-fold envelope form, and FIG. 3 is an explanatory view showing a state in which the pressure-sensitive adhesive of the present invention is applied to a double-layer envelope form, which is a type of print form. DESCRIPTION OF SYMBOLS 1 ... Printing foam 2 ... Pressure-sensitive adhesive 3 ... Silica gel 4 ... Tri-fold enclosing form 5 ... Double-layer enclosing form 6 ... Folding perforation, 7 ... Tearing perforation 8 ... Opening perforation

Claims (1)

[Claims] 1. A NB having a nitrile ratio of 25 to 40% in NBR.
A pressure-sensitive adhesive characterized in that 5 to 40 parts by weight of silica gel is added to 100 parts by weight of R latex.