JPS62273275A - Adhesive for use in waterproof corrugated board - Google Patents

Abstract

PURPOSE:To obtain the titled adhesive outstanding in water resistance and lamination characteristics, capable of low-temperature lamination, free from development of warpage, by dispersing in water, specified proportion of rubber latex, starch and calcium carbonate. CONSTITUTION:The objective adhesive can be obtained by dispersing in water, (A) 100pts.wt. on a solid basis of a rubber latex, (B) 1-100pts.wt. of starch (e.g. potato starch, tapioca starch), and (C) 20-300pts.wt. of calcium carbonate (pref. heavy calcium carbonate with an average particle size 1-20mu).

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention "Technical Field" The present invention relates to an adhesive for corrugators suitable for manufacturing corrugated board, and more specifically, an adhesive that has excellent water resistance and lamination suitability. The present invention relates to a waterproof corrugated board adhesive made of a rubber-based latex composition that can be laminated at low temperatures and suppresses the occurrence of warpage.

"Prior art and its problems" In recent years, cardboard products have been used for a wide range of purposes, such as those in cold chain for fruit, vegetables, and marine products, and those that come into contact with water or ice for a long time inside or outside the box. It has also come to be used in applications where it is used in such conditions.

In addition, cosmetics and composite materials are progressing, and plastic and
By using materials laminated with black film and 8% gold a foil for the liner, we are expanding the range of special applications such as POP displays, moisture-proof corrugated holes, conductive i-corrugated holes, and electromagnetic shielding corrugated cardboard.

Waterproof corrugated cardboard sheets with special functions used for such purposes must have strong water resistance through their paper quality, and the adhesive used to manufacture them must also have water resistance and adhesive properties. It is required to have excellent compatibility. In addition, it is required that the bonding properties be excellent at temperatures that do not exceed the melting point of plastics.

Conventionally, in the production of corrugated board, the so-called stain-hole method, which is a combination of gelatinized starch called the carrier part and non-gelatinized M powder called the main part, has been widely used. It had serious drawbacks such as lack of properties and low-temperature lamination. That is, when a product made using the above-mentioned stain hole is exposed to water, the liner and core peel off within a short period of time.

In addition, the gelatinization temperature must be around 60°, or water containing 75% must be forcibly dried by heating, which may cause problems with low-temperature lamination and warping of the corrugated cardboard sheet due to movement of the material. There was a problem.

In addition, as a method of imparting water resistance to the adhesive described above, it is possible to use high amylose starch or add urea resin, melamine resin, or ketone resin to starch-based adhesives. However, the adhesive thus obtained was unsatisfactory in terms of water resistance, lamination time, pot life, etc.

On the other hand, various compositions using adhesives other than starch, such as polyvinyl alcohol or polyvinyl acetate emulsions, are not sufficiently water resistant and pourable, and are difficult to use when corrugating with conventional stain hole glues and the above adhesives. When switching, there was a problem in that the borax and load sorter during the stain hole period reacted with the above-mentioned throwing and cutting, resulting in thickening and gelling.

To avoid this problem, it may be necessary to pre-clean the glue pan each time, or collect the remaining adhesive after use and wash it with a glue roll or strong acid to prevent it from rusting before switching to stain hole glue. It was necessary. Furthermore, the recovered adhesive could not be treated with wastewater, which caused problems in terms of workability.

``Object of the Invention'' The object of the present invention is to solve the above-mentioned drawbacks of the conventional stain-hole adhesive, polyvinyl alcohol, and polyvinyl acetate adhesive, and to provide a sheet with good water resistance and low-temperature lamination properties, and to prevent water movement. An object of the present invention is to provide an adhesive for waterproof corrugated cardboard that does not cause warpage and has good workability and productivity.

"Structure of the Invention" The present invention provides 1 to 100 parts of starch and 20 to 3 parts of calcium carbonate per 100 parts of rubber latex in terms of solid content.
00 parts of a rubber latex composition with a high solids content dispersed in water.

Comb-based latex is stabilized in the alkaline region and
Under adhesive conditions, it melts and imparts strong normal adhesion, and at the same time forms a film that is insoluble in water. In addition, it does not react with Stinhole adhesive and cause gelation.

In addition, starch not only increases the initial adhesion strength and supports low-temperature and high-speed lamination, but also contributes to the fractional stability of heavy calcium carbonate.

In general, heavy calcium carbonate helps create an adhesive with a high solid content, prevents the adhesive from being absorbed into the paper, and helps develop initial adhesive strength through its quick drying properties.

These compositions work together to create strong water resistance.
This reduces the amount of heating required and improves the adhesion speed.

The rubber latex used in the present invention is a rubber polymer latex that melts under adhesive conditions obtained by overcrowded emulsion polymerization or re-emulsification of a solution polymer and provides relatively strong adhesive strength. Examples of such latexes include polybutadiene rubber latex, polyisoprene rubber latex, styrene butadiene copolymer latex, methyl methacrylate-butadiene copolymer latex, butadiene-acrylonitrile copolymer latex, and Other examples include the above-mentioned rubber polymer latexes modified with copolymerizable olefinic unsaturated compounds. For example, resins used alone or in combination of two or more of copolymerizable ethylenically unsaturated carboxylic acids such as methyl acrylate, ethylenically unsaturated amides such as acrylamide and methacrylamide, and their N-M conversion compounds. A rubber polymer latex with a solid content of 30 to YO% can be used.

As the starch, it is preferable to use cornstarch, wheat starch, starch starch, etc., which are applicable, have a low gelatinization initiation temperature, and have a large water absorption capacity during gelatinization.

Examples include potato N starch, rito sairiki starch, its acetylation, and quaternary ammonium chloride type starch.

The amount of starch is the solid content of rubber polymer latex resin 10
1 to 100 parts of starch to 0 parts is preferred. If this is used in a small amount, there is a risk of calcium carbonate settling or sedimentation, and there is a problem with initial adhesion.If it is added in a larger amount, the viscosity will become high and the coating workability will deteriorate. There are also problems with water resistance and adhesive strength.

As calcium carbonate, heavy calcium carbonate may be used, and in the present invention, heavy calcium carbonate having an average particle size of 1 to 20 U is particularly preferred. That is, if the adhesive is used for less than one day, the viscosity of the adhesive will increase and the coating workability will deteriorate when the adhesive is increased in concentration. On the other hand, if the average particle size exceeds 20 μ, the strength of the adhesive layer itself will be weakened, which will not only reduce the adhesive strength of the cardboard but also cause problems with the stability of the adhesive itself.

The amount of calcium carbonate to be blended is preferably 20 to 300 parts per 100 parts of the solid content of the rubber polymer latex resin. 20
If the amount is less than 300 parts, it will be difficult to achieve high solidity differentiation of the compounded composition, and it will be difficult to improve productivity by speeding up the drying rate, and there will be problems in terms of cost.If it exceeds 300 parts, the desired initial Adhesive strength and permanent adhesive strength cannot be obtained.

In addition, in the present invention, a filler dispersant and an antifoaming agent may be added to the coating as necessary.

"Example J of the Invention Example 1 0.5 parts of sodium tripolyphosphate as a filler dispersant was dissolved and added to 30 parts of the book, 67.5 parts of heavy-duty calcium carbonate with an average particle size of 15 u, and acetyl at a concentration of 40%. Tapioca starch (D, S, 0.03,) slurry 30 parts, solid content 48
% of 38-day latex (5N3 made by Sumitomo Naugatack)
07) Add 100 parts in order while stirring to reduce the solid content to 5.
6%, a viscosity of 1500 cp/25"C, and a pH of 8.7, a waterproof cardboard adhesive was obtained.

Comparative example] Water 330! Add 9 to 75 of high amylose starch. Caustic soda IO, 3k heated to 60°C
q (dissolved water 20β) is added with stirring to form a calice part. Next, 6.3 kq of borax is added to 560 I2 of water (32°C).
, Ketone resin water resistant agent 23 to 9, Chemical main starch 27
Add 9 to 5 to make the main part. Then, by dropping the calice part into the main part while stirring (for 20 to 25 minutes), the result is a finished product with a viscosity of 48 seconds (39°C) and a double water ratio of 2.
A high amylose-based starch waterproof paste No. 6 was obtained.

Next, using the adhesives of Example] and Comparative Example 1, bonding was performed under the following conditions, and the adhesive strength was measured. The results are shown in Table 1.

Manufacturing conditions for cardboard Paper composition: Waterproof RC220X Waterproof RC200X Waterproof RC
220A flute vapor pressure: 12 kq/cm2 Glue clearance: 0.35 mm Lamination speed, 120+n/min Test conditions of laminated sheet Curing after bonding: 20°C 65% RH 24 hours Test piece;
50 x 80 mm 10 sheets Water resistant adhesive strength, measured after being immersed in water at 20°C for one hour (hereinafter referred to as the margin) Table 1. (In the table, SF means the Shinkle Fazer side, and DF means the Double Fazer side.) As shown in Table 1, by using the adhesive of the present invention, there is less resistance. It can be seen that a corrugated cardboard sheet with high water-resistant adhesive strength can be obtained.

Example 2 Instead of the 38-day latex of Example 1, N with a solid content of 58% was used.
BR latex (Sumitomo Naugatac KK SN9+○)
Using 100 parts, in the same way, solids content 60%, type B viscosity lW
A waterproof cardboard adhesive having a temperature of 2000 cp/25°C and a pH of 9.1 was obtained.

Comparative Example-2 Add 4 parts of borax to 390 parts of this book and dissolve it, then add 50 parts of corn starch and 500 parts of vinegar emulsion with a solid content of 48% in order to obtain a solution with a solid content of 31% and a B-type viscosity of 300 cp/2.
A cardboard adhesive having a pH of 4.9 and a temperature of 5°C was obtained.

Then, lamination and adhesive strength measurements were carried out in the same manner as in Example except that the following conditions were changed. The results are shown in Table 2.

Cardboard manufacturing conditions Base paper composition, PP laminated water resistant 220x waterproof RC200XP
22OA flute on P laminated wood Vapor pressure: 4 kq/cm2 Lamination speed, Example 2: 120 m/min Comparative example 2: 70 m/min (hereinafter, blank) Table 2. Physical properties of laminated sheet In the case of Comparative Example 2, the piping pump, group pan, glue roll, doctor roll, etc. had to be washed with water before and after lamination to avoid mixing with stain hole glue.1. Example In the case of No. 2, no problem occurred even when mixed with Steinhole glue.

"Effects of the Invention J As detailed above, the waterproof corrugated adhesive of the present invention consisting of a high solidity composition has excellent water resistance, excellent low-temperature adhesion due to quick drying, and is suitable for use in composite materials for corrugated cardboard. In addition, by mixing the stain-hole adhesive into the glue of the present invention when transferring to the stain-hole adhesive, it can be smoothly bonded to regular corrugated board without collecting it. The manufacturing process is carried out and brings about improvements outside of production.

Patent source: Toppan Printing Co., Ltd.

Claims (2)

[Claims] (1) 1 to 100 parts of starch and 20 to 3 parts of calcium carbonate per 100 parts of rubber latex in terms of solid content weight
A waterproof corrugated board adhesive characterized in that 00 parts are dispersed in water. (2) The adhesive for waterproof corrugated board according to claim 1, which is calcium carbonate or heavy calcium carbonate having an average particle size of 1 to 20 u.