JPH0649853B2 - 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 foams such as sites 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, when the above conventional pressure-sensitive adhesive is applied to a printing foam and used, the adhesive, heat resistance, blocking resistance, and storage stability are not satisfactory.

[Means for Solving Problems] As a result of intensive studies, the present inventor has improved adhesion by adding a tackifier to chloroprene rubber latex, and further added silica gel fine powder to prevent blocking. By improving the heat resistance, wear resistance and heat resistance,
It was found that a superior pressure-sensitive adhesive can be obtained, and the present invention has been completed.

In the present invention, it has been found that when 100 parts by weight of a tackifier is added to 100 parts by weight of chloroprene rubber latex, the adhesive strength is dramatically improved and the long-term stability of the adhesive strength is also improved.
The mixture of SBR latex and tackifier has an average particle size of 20 μm or less, preferably 1 to 10 μm, more preferably 2 μm.
5 to 40 parts by weight of silica gel fine powder of ~ 6μ, preferably
By adding 15 to 30 parts by weight, the adhesive strength, heat resistance, abrasion resistance, blocking resistance, and storage stability can be dramatically improved, and the feeling of having superior performance to conventional pressure-sensitive adhesives. A pressure-sensitive adhesive could be obtained.

As the chloroprene rubber latex and the silica gel in the present invention, those having various kinds and particle sizes can be applied as described in the examples. Particularly, silica gel having an average particle size of 1 to 10 μ is used as the chloroprene rubber latex.
The addition of 15 to 30 parts by weight to 00 parts by weight is particularly excellent in adhesiveness, and is suitable for use in mail envelopes, postcards, various cards, and the feeling described in the other examples. Pressure adhesives can also be used beneficially based on paper, form bonding, and stitching applications.

After applying chloroprene rubber latex as a pressure sensitive adhesive to paper and drying it, even if the adhesives are contacted and pressed,
Although the adhesiveness is weak, the pressure-sensitive adhesive of the present invention exerts various effective properties as a pressure-sensitive adhesive by adding 5 to 40 parts by weight of silica gel to 100 parts by weight of chloroprene rubber latex. The reason for this is not clear, but chloroprene rubber is adsorbed on silica gel to increase the surface area, silica gel acts as a kind of reinforcing agent, and the strength of the adhesive increases, and as shown in FIG. It is considered that this is because the surface of the pressure-sensitive adhesive 2 applied to the printing foam 1 with a thickness of about 5 μ is made uneven by the silica gel 3.

The tackifier used in the present invention includes rosin, modified rosin and their derivatives, polyterpene-based resin,
A terpene modified product, an aliphatic hydrocarbon resin, a cyclopentadiene resin, an aromatic petroleum resin, a phenol resin, an alkylphenol / acetylene resin, a styrene resin, a xylene resin, a coumarone indene resin and the like are included.

Further, the pressure-sensitive adhesive of the present invention is obtained by adding a tackifier and silica gel to chloroprene rubber latex, but a dispersant, a wetting agent, a defoaming agent and the like may be added if necessary.

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, except that the invention is limited in the above claims.
It is not restricted to these particular implementations.

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 applied pressure is about 10 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 was abraded while applying a load of 200 to 500 Kg / cm ² , and 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 Chloroprene latex "DENKA CHLOROPURENELA-50"
(Product name: Denki Kagaku Co., solid content 50%) 100 parts by weight of tackifier "Nopco EB" (Product name: San Nopco, ester gum system, solid content 46%) 100 parts by weight are added and mixed. Use liquid A. Further, 20, 25, 30 parts by weight of silica gel "CYLOID 404" (trade name; manufactured by Fuji Davison Co., Ltd., particle size: 10 μ) was added to 200 parts by weight of the mixed solution A to form pressure-sensitive adhesives a, b, c, respectively. .

Example 2 Chloroprene latex "DENKA CHLOROPURENELA-50"
100 parts by weight of tackifier "Nopco EB-1" (trade name; San Nopco, aliphatic petroleum hydrocarbon resin, solid content 46
%) To prepare a mixed solution B. Further, to 200 parts by weight of the mixed solution B, 2 parts of silica gel "Cyroid 404"
Add 0, 25, 30 parts by weight of pressure sensitive adhesive d, e,
f.

Example 3 Chloroprene latex "NEOPRENE # 502" (trade name;
Showa Neoprene, solid content 50%) 100 parts by weight of tackifier "Pentaline H" (trade name, Rika Hercules, hydrogenated rosin pentaerythritol ester type) 1
Add 00 parts by weight to prepare a mixed solution C. To 200 parts by weight of the mixed solution C, 20, 25, 30 parts by weight of silica gel "SIPERNAT 22S" (trade name; manufactured by Nippon Aerosil Co., Ltd., particle size 5 µ) was added,
The pressure-sensitive adhesives g, h, and i were used.

Example 4 To 100 parts by weight of chloroprene latex "NEOPRENE # 572" was added 100 parts by weight of a tackifier "Foral 105" (trade name: pentaerythitol ester of hydrogenated rosin, manufactured by Rika Hercules Co., Ltd.) to prepare a mixture D. To do. Further, silica gel "SIPERNAT 22S" is added to 200 parts by weight of the mixed solution D 2
Add 5 or 30 parts by weight of pressure sensitive adhesive j, k,
It was set to l.

Example 5 Chloroprene latex "SKYPREN LA502" (trade name;
Toyo Soda Co., Ltd., solid content 52%) To 100 parts by weight, 100 parts by weight of a tackifier "Stevelite Ester 10" (trade name; hydrogenated rosin glycerin ester by Rika Hercules Co., Ltd.) was added and mixed solution E And Silica gel "SIPERNAT 22S" was added to 200 parts by weight of the mixed solution E in an amount of 20, 25, and 30 parts by weight to obtain pressure-sensitive adhesives m, n, and o, respectively.

Comparative Example 1 To 100 parts by weight of natural rubber latex, 3 parts by weight of a tackifier "Hitanol 1501" (trade name; manufactured by Hitachi Chemical Co., Ltd.) was added, and further 10 parts by weight of casein was added to obtain a pressure-sensitive adhesive p.
And

Comparative Example 2 Pressure-sensitive adhesives q, r, and s were prepared in the same manner as in Example 1 except that the tackifier "Nopco EB" was not used.

Comparative Example 3 A pressure-sensitive adhesive t was prepared in the same manner as in Example 1 except that 3.5 parts by weight of silica gel "Cyroid 404" was added.

Comparative Example 4 A pressure-sensitive adhesive u was prepared in the same manner as in Example 1 except that 43.5 parts by weight of silica gel "Cyroid 404" was added.

The pressure-sensitive adhesives a to o of the present invention prepared in the above Examples 1 to 5
Table 1 shows the test results of the adhesiveness, blocking resistance, heat resistance, and abrasion resistance of the pressure-sensitive adhesives p to u prepared in Comparative Examples 1 to 4.

[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 to apply the pressure-sensitive adhesive 2 of the present invention in advance to a thickness of about 3 to 6 μ on the bonding portion of the double-sided sealed foam 5 shown in FIG. Three
In addition to the print form shown in the figure, it is effective for pre-application to print forms such as double-fold envelope forms, postcard forms, various notifications, binding and window-open double-fold envelope forms. It is a thing.

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. 1 …… Printing foam 2 …… Pressure-sensitive adhesive 3 …… Silica gel 4 …… Tri-fold envelope form 5 …… Double-layer envelope form 6 …… Folding perforation, 7 …… Cutout perforation 8 ...... Perforation for opening

Claims (1)

[Claims] 1. Chloroprene rubber latex 100 parts by weight, tackifier 100 parts by weight and silica gel 5-40.
A pressure-sensitive adhesive in the form of a printing foam consisting of parts by weight.